FIELD

[0001] The present disclosure relates to a transmission gear synchronizer having components formed of thermoplastic material.

BACKGROUND

[0002] Transmission gear synchronizers can be used in mechanical manual transmissions, dual clutch transmissions, automated transmissions, sequential transmissions or any mechanical device that may require differential speed equalization. A transmission gear synchronizer allows for a smooth engagement of gears during shifting events.

SUMMARY

[0003] A transmission gear synchronizer according to one example of the present disclosure includes a sliding sleeve, a hub and an inner synchronization ring. The sliding sleeve has an inner surface defining a sleeve spline. The hub is received within the sliding sleeve. The hub has a plurality of gear teeth extending radially outward from a root diameter of the hub. The plurality of gear teeth are configured to engage the sleeve spline. A notch is disposed proximate the root diameter of the hub and spaced apart from the plurality of gear teeth. The inner synchronization ring is formed of a thermoplastic material.

[0004] According to other features, the transmission gear synchronizer further includes an engagement ring and a blocker ring. The sliding sleeve is prevented from engaging the engagement ring by the blocker ring. The blocker ring is configured to selectively frictionally engage a cone of the engagement ring. The inner synchronization ring is formed by one of injection molding, compression molding and a machining process. The inner synchronization ring is formed exclusively of thermoplastic polymer. The inner synchronization ring is lining-free. The inner synchronization ring is coating-free. The transmission gear synchronizer further includes an intermediate synchronization ring.

[0005] A transmission gear synchronizer according to one example of the present disclosure includes a sliding sleeve, a hub and an intermediate synchronization ring. The sliding sleeve has an inner surface defining a sleeve spline. The hub is received within the sliding sleeve. The hub has a plurality of gear teeth extending radially outward from a root diameter of the hub. The plurality of gear teeth are configured to engage the sleeve spline. A notch is disposed proximate the root diameter of the hub and spaced apart from the plurality of gear teeth. The intermediate synchronization ring is formed of a thermoplastic material.

[0006] According to other features, the transmission gear synchronizer further includes an engagement ring and a blocker ring. The sliding sleeve is prevented from engaging the engagement ring by the blocker ring. The blocker ring is configured to selectively frictionally engage a cone of the engagement ring. The intermediate synchronization ring is formed by one of injection molding, compression molding and a machining process. The intermediate synchronization ring is formed exclusively of thermoplastic polymer. The intermediate synchronization ring is lining-free. The intermediate synchronization ring is coating-free. The transmission gear synchronizer further includes an inner synchronization ring.

[0007] A transmission gear synchronizer constructed in accordance to another example of the present disclosure includes a polymeric synchronizer cone assembly comprising a synchronizer flange, a blocker ring and a synchronizer cone formed of polymeric material. The synchronizer flange is formed of steel. The blocker ring is formed of steel.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a perspective view of a compound manual transmission with the case partially removed; [0009] FIG. 2 is a perspective view of an exemplary transmission gear synchronizer with a sliding sleeve assembly in a neutral position;

[0010] FIG. 3 is a perspective view of an exemplary transmission gear synchronizer with a sliding sleeve in a locked position with a gear;

[0011] FIG. 4 is an exploded perspective view of an exemplary transmission gear synchronizer;

[0012] FIGS. 5A, 5B, are partial sectional views of a sliding sleeve assembly in an engaged position with a blocker ring clutch tooth;

[0013] FIG. 6 is a partial sectional view of a sliding sleeve assembly in an engaged position with a blocker ring clutch tooth;

[0014] FIG. 7 is a perspective view of an exemplary thermoplastic blocker ring;

[0015] FIG. 8 is a partial perspective view of an exemplary thermoplastic blocker ring; FIG. 9 is a perspective view of an exemplary thermoplastic blocker ring;

[0016] FIG. 10 is an exploded perspective view of an exemplary transmission gear synchronizer constructed in accordance to another example of the present disclosure and that incorporates inner rings formed of thermoplastic material;

[0017] FIG. 11 is an exploded perspective view of an exemplary transmission gear synchronizer constructed in accordance to another example of the present disclosure and that incorporates intermediate rings formed of thermoplastic material;

[0018] FIG. 12A is a perspective view of an exemplary transmission gear synchronizer constructed in accordance to another example of the present disclosure and that incorporates a gear cone formed of thermoplastic material;

[0019] FIG. 12B is a sectional view of the gear synchronizer of FIG. 12A;

[0020] FIG. 12C is an exploded perspective view of the gear synchronizer of FIG. 12A;

[0021] FIG. 12D is a top perspective view of the steel synchronizer flange of FIG. 12A; [0022] FIG. 12E is a top perspective view of the polymeric synchronizer cone of FIG. 12A; and

[0023] FIG. 12F is a top perspective view of the steel blocker ring of FIG. 12A.

DESCRIPTION

[0024] Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

[0025] Referring to FIG. 1 , a transmission 10 may be provided with a vehicle such as an automobile, a truck or the like. The transmission 10 may be configured as a mechanical manual transmission, a dual clutch transmission, an automated transmission, a sequential transmission, or a mechanical device that may require differential speed equalization. The transmission 10 transmits power from a power source, such as an internal combustion engine to a drive axle.

[0026] The transmission 10 may include an input shaft 20 configured to engage the power source (not shown) via a clutch, a fluid coupling, or a flywheel. The transmission 10 may include an output shaft 22 configured to engage a differential or drive member (not shown). The combination of the input shaft 20 and the output shaft 22 is commonly referred to as the transmission main shaft. In at least one embodiment, the output shaft 22 includes a yoke 24 coupled to a differential or a drive member.

[0027] The transmission 10 may include a first gear set 30, a second gear set 32, and a transmission gear synchronizer 34. The first gear set 30, the second gear set 32, and the transmission gear synchronizer 34 each rotatably disposed within a transmission housing 36. The first gear set 30 may include a first plurality of gears 40 disposed concentrically about a first transmission shaft 42 such that the first gear set 30 is supported by the first transmission shaft 42. The first gear set 30 may be journaled on the first transmission shaft 42. In at least one embodiment, the first plurality of gears 40 may include a first gear 44 spaced apart from a second gear 46. The first gear 44 and the second gear 46 may be disposed substantially perpendicular to a longitudinal axis 48 of the first transmission shaft 42. The second gear set 32 may include a second plurality of gears 50 disposed concentrically about a second transmission shaft 52 such that the second gear set 32 is supported by the second transmission shaft 52. The second transmission shaft 52 may commonly be referred to as a countershaft.

[0028] The first transmission shaft 42 may be spaced apart from and disposed substantially parallel to the second transmission shaft 52. In at least one embodiment, the second plurality of gears 50 may include a third gear 54 spaced apart from a fourth gear 56. The third gear 54 and the fourth gear 56 may be disposed substantially perpendicular to a longitudinal axis 48 of the second transmission shaft 52. The second gear set 32 may be journaled on the second transmission shaft 52.

[0029] The first gear set 30 may be rotatably aligned with the second gear set 32. The first plurality of gears 40 of the first gear set 30 engage a corresponding gear of the second plurality gears 50 of the second gear set 32 such that the second gear set 32 are in meshed engagement with the first gear set 30. In at least one embodiment, the first gear 44 may remain in constant mesh or engagement with the third gear 54 and/or the second gear 46 may remain in constant mesh or engagement with the fourth gear 56.

[0030] The first plurality of gears 40 and the second plurality of gears 50 may be configured to transmit torque from the input shaft 20 to the output shaft 22. The first plurality of gears 40 and the second plurality gears 50 are configured to provide multiple forward and/or reverse gear ratios or torque ratios. An operator of a vehicle incorporating the transmission 10 may selectively engage at least one of the gears of the first plurality of gears 40 of the first gear set 30 and/or at least one of the gears of the second plurality of gears 50 of the second gear set 32. The selective engagement of the gears defines a plurality of torque flow paths through the first gear set 30 and the second gear set 32 to vary an output torque or gear ratio of the transmission 10.

[0031] The shift lever 60 may be operatively connected to at least one shift fork 62 by a set of linkages (not shown). The shift fork 62 translates a sliding gear selector, collar, or sliding sleeve 70 between gears of the first plurality of gears 40 and/or gears of the second plurality of gears 50. A sliding sleeve 70 may be rotatably disposed about the first and/or second transmission shaft 42, 52.

[0032] The sliding sleeve 70 may translate towards a desired gear responsive to movement of the shift fork 62. The sliding sleeve 70 may be configured to lock onto a freely spinning gear or engagement ring associated with the desired gear to lock the freely spinning gear associated with the desired gear to the transmission shaft such that the transmission shaft 42, 52 spins together with the desired gear. The engagement of the sliding sleeve 70 with the desired gear may result in nibble, notch, or other transmission effects that may negatively affect transmission shift quality if the rotational speed of collar is not substantially similar to the rotational speed of the desired gear. The transmission gear synchronizer 34 may be provided to brake or accelerate the sliding sleeve 70 and/or the desired gear such that the rotational speed of the sliding sleeve 70 and the desired gear are substantially similar to dampen or minimize the effects of notch, nibble, or other undesired transmission shift effects. In at least one embodiment, the transmission gear synchronizer 34 may adjust the rotational speed of at least one of the first transmission shaft 42 and the second transmission shaft 52 and the desired gear.

[0033] Referring to FIG. 2, the transmission gear synchronizer 34 is shown with the sliding sleeve 70 in a neutral position between the first gear 44 and the second gear 46. Referring to FIG. 3, the transmission gear synchronizer 34 is shown with the sliding sleeve 70 translated towards the desired gear (e.g. the first gear 44) responsive to actuation by the shift fork 62. [0034] The transmission gear synchronizer 34 may be disposed concentrically about the first transmission shaft 42 such that the transmission gear synchronizer 34 is supported by the first transmission shaft 42. The transmission gear synchronizer 34 may be disposed between or adjacent to the first gear 44 and the second gear 46 of the first plurality of gears 40 of the first gear set 30. In at least one embodiment, the transmission gear synchronizer 34 may be disposed concentrically about the second transmission shaft 52 such that the transmission gear synchronizer 34 is supported by the second transmission shaft 52. The transmission gear synchronizer 34 may be disposed between or adjacent to the third gear 54 and the fourth gear 56 of the second plurality of gears 50 of the second gear set 32.

[0035] Referring to FIG. 4, an exploded perspective view of an exemplary transmission gear synchronizer 34 is shown. The transmission gear synchronizer 34 may be a triple cone transmission gear synchronizer however other transmission gear synchronizer configurations are contemplated such as a single cone, dual cone, or other multi-cone transmission gear synchronizers. The transmission gear synchronizer 34 may include a sliding sleeve 70, a fixed hub 72, a synchronization ring or blocker ring 74, an inner synchronizer ring assembly 76, and an engagement ring 78. In at least one embodiment, the transmission gear synchronizer 34 may be a single cone transmission gear synchronizer having the inner synchronization ring assembly 76 excluded. In at least one embodiment, the transmission gear synchronizer 34 may be a dual cone transmission gear synchronizer having at least one of an intermediate synchronization ring 80 or the inner synchronization ring 82 excluded.

[0036] Irrespective of the transmission gear synchronizer 34 configuration, the transmission gear synchronization process follows similar steps during a transmission shift event. The transmission shift event may be a transmission upshift event when a transmission gear ratio moves from a lower gear ratio to a higher gear ratio, e.g. N-1 , 1 -2, 2-3, 3-4, etc. The transmission shift event may be a transmission downshift event when the transmission gear ratio moves from a higher gear ratio to a lower gear ratio, e.g. 4-3, 3-2, 2-1 , 1 - N, etc. During a transmission shift event, the sliding sleeve 70 is moved by the shift fork 62 towards the desired gear to be engaged. Responsive to a rotational speed difference between the desired gear and the combination of the sliding sleeve 70 and the fixed hub 72, which may be referred to as a sliding sleeve assembly 84, the sliding sleeve 70 is prevented from engaging the engagement ring 78 by the blocker ring 74.

[0037] The blocker ring 74 is configured to frictionally engage a cone of the engagement ring 78, the intermediate synchronization ring 80, or the inner synchronization ring 82 associated with the desired gear. The frictional engagement generates a frictional torque to brake or accelerate the rotational speed of the sliding sleeve assembly 84 and/or the engagement ring 78, such that the rotational speeds of the sliding sleeve assembly 84 and the engagement ring 78 or the desired gear are synchronized. Responsive to the synchronization of the rotational speeds, the sliding sleeve 70 may be further translated to engage the engagement ring 78 to complete the transmission shift event.

[0038] The sliding sleeve 70 may be configured as a generally cylindrical body disposed concentrically about an axis of the first transmission shaft 42. The sliding sleeve 70 may have an outer surface 90 and an inner surface 92. The outer surface 90 may define an engagement groove 94 that may receive at least a portion of the shift fork 62. The movement of the shift fork 62 within the engagement groove 94 may translate the sliding sleeve 70 away from the neutral position or from a current gear towards the desired gear.

[0039] The sliding sleeve 70 may be configured as an internal gear having a sleeve spline disposed about the inner surface 92. The sleeve spline may be configured as a plurality of sleeve teeth 96 that extend radially inward from the inner surface 92 of the sliding sleeve 70 towards the first transmission shaft 42.

[0040] Each sleeve tooth 100 of the plurality of sleeve teeth 96 has a tip 102. The tip 102 may be angled with respect to the longitudinal axis 48 of the first transmission shaft 42. The tip 102 may be defined by a first surface 104 and a second surface 106. The first surface 104 may be disposed at a first angle relative to the longitudinal axis 48 of the first transmission shaft 42. The second surface 106 may be disposed at a second angle relative to the longitudinal axis 48 of the first transmission shaft 42. The first surface 104 and the second surface 106 may define an angle Q.

[0041] Referring to FIGS. 5A, 5B, and 6, a partial sectional view of a sleeve tooth 100 of the sliding sleeve 70 in an engaged position with the blocker ring 74. In at least one embodiment, the first surface 104 and the second surface 106 may be disposed at an obtuse angle Qo with respect to each other. Referring to FIG. 6, in at least one embodiment, the first surface 104 and the second surface 106 may be disposed at an acute angle, QA, with respect to each other.

[0042] The first surface 104 may have a first length, h. The second surface 106 may have a second length, I2. As shown in FIGS. 5A and 5B, the second length, I2, may be greater than the first length, h, such that the first surface 104 and the second surface 106 are asymmetric. As shown in FIG. 6, the first length, h, and the second length, I2, may be substantially similar to each other, such that the first surface 104 and the second surface 106 are symmetric.

[0043] The sleeve tooth 100 may have a body portion 110. The body portion 110 may have a first side surface 112 extending from the inner surface 92 of the sliding sleeve 70 to the first surface 104. The body portion 110 may have a second side surface 114 extending from the inner surface 92 of the sliding sleeve 70 to the second surface 106. The first side surface 112 may be disposed at a third angle relative to the longitudinal axis 48 of the first transmission shaft 42. The second side surface 114 may be disposed at a fourth angle relative to the longitudinal axis 48 of the first transmission shaft 42. The first side surface 112 and the second side surface 114 may be spaced apart from each other and disposed in a non-parallel relationship. The first side surface 112 and the second side surface 114 may become progressively farther apart from one another along an axial direction along the sleeve tooth 100 towards the tip 102.

[0044] The first side surface 112 may have a length, Isi . The second side surface 114 may have a length, IS2. The length, Isi, and the length, Is2, may be substantially similar. The length, Isi, and the length, Is2, may be greater than the first length, Isi, and the second length, Is2, respectively.

[0045] The fixed hub 72 is configured to be slidably received within the sliding sleeve 70 which may define the sliding sleeve assembly 84. The first transmission shaft 42 may include a plurality of splined teeth disposed about an outer surface of the first transmission shaft 42. The fixed hub 72 may engage at least one of the plurality of splined teeth of the first transmission shaft 42 via splined teeth disposed about an inner diameter of the fixed hub 72.

[0046] The fixed hub 72 may have a plurality of gear teeth 120. The plurality of gear teeth 120 extend radially outward from a root diameter of the fixed hub 72. The plurality of gear teeth 120 may be configured to engage or mesh with the sleeve spline or plurality of sleeve teeth 96. The fixed hub 72 may define a notch 122 disposed proximate the root diameter of the fixed hub 72 and spaced apart from the plurality of gear teeth 120.

[0047] The fixed hub 72 may include at least one pre-energizer 130. The pre-energizer 130 may be configured to engage at least one sleeve tooth 100 of the plurality of sleeve teeth 96. The pre-energizer 130 may include a roller, a strut, or a spring disposed about a plunger. The pre- energizer 130 may be received within a cavity extending radially inward from the root diameter of the fixed hub 72. The pre-energizer 130 may be retained within the cavity by the internal diameter of the sliding sleeve 70 or the plurality of sleeve teeth 96.

[0048] Responsive to movement of the gear selector fork 62, the sliding sleeve 70 may be moved towards the desired gear, for example the first gear 44 or the second gear 46. The pre-energizer 130 assists in translating the sliding sleeve 70 towards the desired gear during gear synchronization and engagement.

[0049] The blocker ring 74 may be disposed proximate the fixed hub 72. The blocker ring 74 may have a first end region 140 disposed proximate the engagement ring 78. The blocker ring 74 may have a second end 142 spaced apart from the first end region 140 and a generally cylindrical body 144 extending therebetween. The generally cylindrical body 144 may have an outer surface 146 and an inner surface 148. The generally cylindrical body 144 may be disposed concentrically about the axis 48 of the first transmission shaft 42.

[0050] The blocker ring 74 may be disposed between the desired gear, the engagement ring 78, and the sliding sleeve assembly 84. In at least one embodiment, a second blocker ring may be spaced apart from the blocker ring 74. The second blocker ring may be disposed on another side of the fixed hub 72 between another desired gear and another engagement ring.

[0051] The blocker ring 74 is urged towards the desired gear responsive to movement of the gear selector fork 62 and the sliding sleeve 70 towards the desired gear. As the blocker ring 74 is urged towards the desired gear, the blocker ring 74 may engage a cone of the engagement ring 78 associated with the desired gear. The engagement of the blocker ring 74 with the cone of the engagement ring 78 associated with the desired gear may generate friction resulting in rotation of the blocker ring 74. The frictional engagement of the blocker ring 74 with the cone may brake or accelerate at least one of the sliding sleeve assembly 84 and the engagement ring 78 to approximately match the rotational speed of the desired gear to complete the transmission shift event.

[0052] The main function of the blocker ring 74 is intrinsically related to its frictional properties because the blocker ring 74 serves as a frictional member to accelerate or brake various components of the transmission 10 involved in the transmission shift event. The blocker ring 74 and the cone of the engagement ring 78 may act as a frictional clutch when they are engaged. Commonly blocker rings are made out of brass, aluminum, or other ferrous alloys. Various surfaces of the metallic blocker ring may be lined or coated with friction materials such as special papers, fibers, brass, or molybdenum to improve the frictional properties of the metallic blocker ring.

[0053] Metallic blocker rings may be manufactured by employing extensive machining, coating, and heat treatment processes to obtain the desired frictional properties. Some thermoplastic materials may have both mechanical and frictional properties suitable for blocker rings, to enable the use of the thermoplastic material instead of a ferrous alloy and without a separate frictional lining or coating. As such, the blocker ring 74 may be produced by an injection molding process with minimal machining.

[0054] The blocker ring 74 comprising a thermoplastic material lighter in weight than a metallic blocker ring. The blocker ring 74 comprising a thermoplastic material may have comparable strength, stiffness, and endurance as a metallic blocker ring. The blocker ring 74 comprising a thermoplastic material may have additional teeth disposed about the periphery that may improve shift quality and wear life as compared to a metallic blocker ring.

[0055] The thermoplastic material may be a high-performance polymer composite. The high-performance polymer composite may have a tensile strength within a range defined by 200-500 MPa. The high- performance polymer composite may have 20%-40% carbon fill, such as a PEEK grade high-performance polymer composite with carbon fill. The carbon fibers used for the carbon fill may have a length of 0.5 mm to 10 mm and diameter of 0.05 mm to 1 mm.

[0056] In at least one embodiment, the high-performance polymer composite may include glass or aramid fibers, or powdered ceramic fillers from 0-20% in weight. These fillers may improve the mechanical properties and the coefficient of friction of the blocker ring 74. Exemplary material properties of high-performance polymers composites compared to brass are shown in Table 1. Table 1 may define ranges of the material properties for the blocker ring 74.

[0057]

composition including 40% high performance carbon fiber fill. For example, the high performance carbon fiber may have a length of 3 mm and a diameter of 0.4 mm. The 30% CF may be a thermoplastic having a composition including 30% carbon fiber fill. For example, the high performance carbon fiber may have a length of 1 mm and a diameter of 0.1 mm.

[0059] The blocker ring 74 formed of the thermoplastic material may have a first end region 140, a second end region 142, and a cylindrical body 144 extending between the first end region 140 and the second end region 142. The first end region 140 may be disposed proximate the engagement ring 78. The second end region 142 may be disposed proximate the sleeve assembly 84.

[0060] The first end region 140 may be provided with a plurality of molded clutch teeth 150. The second end region 142 may be provided with a molded spline or plurality of molded grooves 152. The cylindrical body 144 may be provided with a molded engagement pad 154.

[0061] The plurality of molded clutch teeth 150 may be disposed continuously about a circumference of the first region 140. The plurality of molded clutch teeth 150 may extend radially outward from a root diameter, Rd, of the blocker ring 74.

[0062] Each molded clutch tooth 160 of the plurality of molded clutch teeth 150 have an angled end surface 162. The angled end surface 162 may be angled towards the first end region 140 and angled away from the second end region 142. The angled end surface 162 may be defined by a third surface 164 and a fourth surface 166. The third surface 164 and the fourth surface 166 may be angled towards the first end region 140 and inclined with respect to the second end region 142. The third surface 164 may be disposed at an angle relative to the longitudinal axis 48 of the first transmission shaft 42. The fourth surface 166 may be disposed at an angle relative to the longitudinal axis 48 of the first transmission shaft 42. The third surface 164 and the fourth surface 166 may define an angle, Q. Referring to FIGS. 5-6, the third surface 164 and the fourth surface 166 may be disposed at an acute angle, with respect to each other.

[0063] The third surface 164 may have a third length, b. The fourth surface 166 may have a fourth length, U. The third length, b, and the fourth length, U, may be substantially similar to each other, such that the third surface 164 and the fourth surface 166 are symmetric.

[0064] The plurality of molded clutch teeth 150 may be configured to engage the plurality of sleeve teeth 96 during a transmission shift event. As shown in FIG. 5A, during a transmission upshift event the third surface 164 of the molded clutch tooth 160 engages the second surface 106 of the sleeve tooth 100. The engagement between the third surface 164 and the second surface 106 defines a first contact area 170. As shown in FIG. 5B, during a transmission down shift event the fourth surface 166 of an adjacent molded clutch tooth engages the first surface 104 of the sleeve tooth 100. The engagement between the fourth surface 166 and the first surface 104 defines a second contact area 172. The asymmetric design of the first surface 104 and the second surface 106 may enable the first contact area 170 to be a larger than the second contact area 172.

[0065] As shown in FIG. 6, during a transmission upshift event and a transmission downshift event, the symmetric design of the first surface 104 and the second surface 106 may enable the first contact area 170 to be substantially similar to the second contact area 172. The symmetric design of the first surface 104 and the second surface 106 and the symmetric design of the third surface 164 and the fourth surface 166 may improve the wear life of the molded clutch tooth 160.

[0066] The inner surface 148 of the generally cylindrical body 144 may have a plurality of molded grooves 152 defined by the inner surface 148. Each molded groove of the plurality of molded grooves 152 may extend in an axial direction along the inner surface 148 of the cylindrical body 144. Each molded groove may be disposed substantially parallel to the axis 48 of the first transmission shaft 42.

[0067] The plurality of molded grooves 152 may be configured as a friction surface. Responsive to the sliding sleeve 70 translating the blocker ring 74 towards a cone of the engagement ring 78 during a transmission event, the plurality of molded grooves 152 engages the cone of the engagement ring 78 responsive to a difference in rotational speed between the desired gear and the sleeve assembly 84. The plurality of molded grooves 152 engaging the cone of the engagement ring 78 in conjunction with the plurality of molded clutch teeth 150 engaging the plurality of sleeve teeth 96 enables the blocker ring 74 to synchronize the rotational speeds of the desired gear and the sleeve assembly 84.

[0068] The outer surface 146 may have a molded engagement pad 154 extending radially outwardly from the outer surface 146 of the cylindrical body 144. The molded engagement pad 154 may be spaced apart from the first end region 140. The molded engagement pad 154 may be disposed proximate the second end region 142. In at least one embodiment, the outer diameter of the outer surface 146 may be less than the root diameter, Rd, of the first end region 140, such that the first end region 140 and the cylindrical body 144 are stepped with respect to each other.

[0069] The molded engagement pad 154 may be configured to nest within or mate with the notch 122 of the fixed hub 72 of the sliding sleeve assembly 84. The molded engagement pad 154 proximately aligns the plurality of molded clutch teeth 150 relative to the plurality of sleeve teeth 98 of the sleeve spline 96. The molded engagement pad 154 nested within the notch 122 permits relative movement between the blocker ring 74 and the sliding sleeve assembly 84, including the sliding sleeve 70 and the fixed hub 72. Additionally, the second end 142 of the cylindrical body 144 may define a recess 180. The recess 180 may be disposed proximate the molded engagement pad 154 and configured as an indexing slot. The indexing slot clocks the blocker ring 74 relative to the sliding sleeve assembly 84.

[0070] The blocker ring 74 may be formed by a process comprising injection molding. The blocker ring 74 may be formed as a unitary body including the molded features such as the molded clutch teeth 150, the plurality of molded grooves 152, the molded engagement pad 154, and the recess 180. The injection molding process may inject the thermoplastic material into a mold cavity through at least three injection gates 200.

[0071] At least one injection gate 200 may be located proximate the molded engagement pad 154. In at least one injection molding process, the injection gates 200 may be equally spaced apart such that the resulting molded engagement pad 154 are equally spaced apart at 120 degree intervals. The equal spacing of the injection gates 200 and the resulting molded engagement pads 154 may improve the mechanical properties of the blocker ring 74 such as stiffness, strength, etc. and minimize geometric distortions.

[0072] The engagement ring 78 may be disposed between the desired gear and the blocker ring 74. The engagement ring 78 has a plurality of gear teeth 190 extending radially outward from a root diameter, Re, of the engagement ring 78. The plurality of sleeve teeth 96 may be configured to engage the plurality of gear teeth 190 during a transmission shift event subsequent to or simultaneously with the rotational speed of the desired gear and the sliding sleeve assembly 84 being approximately synchronized.

[0073] The engagement ring 78 may have a cone 192 extending axially away from a surface 194 of the engagement ring 78. The cone 192 of the engagement ring 78 may extend, tapering towards the fixed hub 72 of the sliding sleeve assembly 84. The frictional engagement between the plurality of molded grooves 152 and the cone 192 of the engagement ring 78 defines a cone clutch.

[0074] Turning now to FIG. 10, a transmission gear synchronizer constructed in accordance to additional features is shown and generally identified at reference number 234. Unless otherwise described herein, the transmission gear synchronizer 234 can be used in place of the transmission gear synchronizer 34 in the transmission 10 described above. A first gear 244 is spaced apart from a second gear 246. The transmission gear synchronizer 234 may include a sliding sleeve 70 (see FIG. 3), a fixed hub 72 (see FIG. 3), a synchronization ring or blocker ring 274, an inner synchronizer ring assembly 276, and an engagement ring 278.

[0075] Responsive to a rotational speed difference between the desired gear and the combination of the sliding sleeve 70 and the fixed hub 72, which may be referred to as a sliding sleeve assembly 284, the sliding sleeve 70 is prevented from engaging the engagement ring 278 by the blocker ring 274. The blocker ring 274 is configured to frictionally engage a cone of the engagement ring 278, the intermediate synchronization ring 280, or the inner synchronization ring 282 associated with the desired gear. In FIG. 10, the inner synchronization ring 82 is shown replaced by the inner synchronization ring 282 according to additional features of the present disclosure. The inner synchronization ring 282 is formed of a polymeric material.

[0076] The frictional engagement generates a frictional torque to brake or accelerate the rotational speed of the sliding sleeve assembly 284 and/or the engagement ring 278, such that the rotational speeds of the sliding sleeve assembly 284 and the engagement ring 278 or the desired gear are synchronized. Responsive to the synchronization of the rotational speeds, the sliding sleeve 70 may be further translated to engage the engagement ring 278 to complete the transmission shift event.

[0077] Returning now to the inner synchronization ring 282, the inner synchronization ring 282 can be made of thermoplastic polymers by injection molding, compression molding or machining process. The inner synchronization ring 282 can be used for double and triple cone or any plurality of synchronizer cones. The inner synchronization ring 82 is typically formed of brass or ferrous alloys. The main function of the inner synchronizer rings is intrinsically related to its friction properties. To have this property with durability, inner synchronizer rings are usually lined with friction materials like carbon fibers, Molybdenum, special papers, brass or other material. Some thermoplastics grades have both mechanical and friction properties. In this regard, the thermoplastic material can eliminate the need of linings and/or coatings. The inner synchronization ring 282 can be formed exclusively of a thermoplastic polymer. In other words, the inner synchronization ring 282 can be lining-free or coating-free.

[0078] The inner synchronization ring 282 provides cost advantages over conventional inner synchronization rings. Further, a thermoplastic inner synchronization ring 282 reduces weight and has higher resistance to torsional vibration and provides noise vibration harshness (NVH) improvements such as mitigating blocker ring rattle noise. The teachings of the thermoplastic inner synchronization ring 282 are not limited to mechanical manual transmission. For example, the inner synchronization ring 282 may be used in dual clutch transmission, automated transmission, sequential transmissions and any mechanical devices that requires differential speed equalization.

[0079] Turning now to FIG. 11 , a transmission gear synchronizer constructed in accordance to additional features is shown and generally identified at reference number 334. Unless otherwise described herein, the transmission gear synchronizer 334 can be used in place of the transmission gear synchronizer 34 in the transmission 10 described above. A first gear 344 is spaced apart from a second gear 346. The transmission gear synchronizer 334 may include a sliding sleeve 70 (see FIG. 3), a fixed hub 72 (see FIG. 3), a synchronization ring or blocker ring 374, an inner synchronizer ring assembly 376, and an engagement ring 378. Responsive to a rotational speed difference between the desired gear and the combination of the sliding sleeve 70 and the fixed hub 72, which may be referred to as a sliding sleeve assembly 384, the sliding sleeve 70 is prevented from engaging the engagement ring 378 by the blocker ring 374. The blocker ring 374 is configured to frictionally engage a cone of the engagement ring 378, the intermediate synchronization ring 380, or the inner synchronization ring 382 associated with the desired gear. In FIG. 11 , the intermediate synchronization ring 380 is constructed in according to additional features of the present disclosure.

[0080] The intermediate synchronization ring 380 is formed of a polymeric material. The intermediate synchronization ring 380 can be made of thermoplastic polymers by injection molding, compression molding or machining process. The advantages of constructing the intermediate synchronization ring 380 of a polymeric material as similar to those described above with respect to the inner synchronization ring 282.

[0081] The intermediate synchronization ring 380 can be used for double and triple cone or any plurality of synchronizer cones. The intermediate synchronization ring 380 is typically formed of brass or ferrous alloys. The main function of the intermediate synchronizer rings is intrinsically related to its friction properties. To have this property with durability, inner synchronizer rings are usually lined with friction materials like carbon fibers, Molybdenum, special papers, brass or other material. Some thermoplastics grades have both mechanical and friction properties. In this regard, the thermoplastic material can eliminate the need of linings and/or coatings.

[0082] The intermediate synchronization ring 380 can be formed exclusively of a thermoplastic polymer. In other words, the intermediate synchronization ring 380 can be lining-free or coating-free. The intermediate synchronization ring 380 provides cost advantages over conventional intermediate synchronization rings. Further, a thermoplastic intermediate synchronization ring 380 reduces weight and has higher resistance to torsional vibration and provides noise vibration harshness (NVH) improvements such as mitigating blocker ring rattle noise. The teachings of the thermoplastic intermediate synchronization ring 380 are not limited to mechanical manual transmission. For example, the intermediate synchronization ring 380 may be used in dual clutch transmission, automated transmission, sequential transmissions and any mechanical devices that requires differential speed equalization.

[0083] Turning now to FIGS. 12A - 12F, a polymeric synchronizer cone assembly constructed in accordance to another example of the present disclosure is shown and generally identified at reference 410. The polymeric synchronizer cone assembly 410 generally includes a synchronizer flange 420, a blocker ring 430 and a synchronizer cone 440. In the polymeric synchronizer cone assembly 410, the synchronizer flange 420 and the blocker ring 430 are formed of steel however the synchronizer cone 440 is made of polymeric material. The metal was preserved in the flange with the jaw clutch due to the stress limits required for transmitting torque. The synchronizer cone 440 can be formed by injection molding, compression molding or machining process. The resulting hardware can take part of a single, double and triple cone or any plurality of design as a friction element.

[0084] The polymeric synchronizer cone 440 will have two different functions; a structural function and a friction function. As a friction element, it is no longer needed to require honed surfaces to keep the suitable roughness as in the metallic cones described above. Further, friction linings are not needed such as the carbon based stripes at the counter parts as some thermoplastic grades have both mechanical and friction properties. The polymeric synchronizer cone 440 provides similar benefits as described above with the other polymeric components. It will be appreciated that the various polymeric components described herein may be used individually or in various combinations in any of the transmission gear synchronizers described herein.

[0085] While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the present invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the present invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the present invention. For example, while the inner synchronization ring 282, the intermediate synchronization ring 380 and the polymeric synchronizer cone 440 have been described in separate examples, two or all of these components may be used in a single transmission gear synchronizer.

[0086] It should be understood that the mixing and matching of features, elements, methodologies and/or functions between various examples may be expressly contemplated herein so that one skilled in the art would appreciate from the present teachings that features, elements and/or functions of one example may be incorporated into another example as appropriate, unless described otherwise above.