TECHNICAL FIELD

The present invention relates to driveshafts provided with protective bellow on the movable parts.

PRIOR ART

In vehicles, transmission means are used to transmit rotational power from the engine or transmission assemblies to rotate one or more wheels. Driveshafts, as a commonly used drivetrain, include a central bearing and a yoke in addition to the universal joint and ensure a smooth transfer of driving force despite relative position changes between the front and rear parts of the vehicle. Due to the high torque transmitted, the driveshafts are designed to have high torsional stiffness and sufficient bending stiffness.

In the driveshaft between the front shaft and the rear shaft is situated hanger assembly. A bellow is mounted on the sliding shaft passing through the bearing assembly, at one end close to the bearing assembly. The bellow is mounted on the slip stub on the one hand to an outer periphery defining a bearing region near the bearing assembly of the sliding shaft. In the present construction a space for the bellow connection is reserved on the sliding shaft.

US5961388A patent publication shows a bellow assembly used in the driveshaft. A sliding yoke and narrowed diameter portion of the driveshaft is shown. In the convoluted bellow structure, a sealing element protects the splined connection between the sliding yoke and the narrowed diameter. The sliding yoke comprises a hollow cylindrical end portion and a yoke portion. A circumferential groove is formed on the outer surface of the sliding yoke tube end in the opposite direction to the yoke.

BRIEF DESCRIPTION OF THE INVENTION

The object of the invention is to shorten the bellow and slip stub length of the driveshaft with spline assembly. In order to reach above objective, the invention relates to a driveshaft comprising an elongated rotary slip stub; a tube sleeve telescopically engaged to the slip stub; a bearing assembly mounted on the slip stub by means of a roller at a vicinity of a movable end of the tube sleeve and a bellow secured to the adjacent tube sleeve from a distal end such that surrounding an outer periphery. The driveshaft further comprises a retaining part which is provided on the bearing assembly and holding the bellow on the bearing assembly such that the bellow is secured directly to the bearing assembly from a proximal end. The retaining part secures the bellow to the bearing assembly, eliminating the need to reserve a further connection part on the shaft. The bearing assembly may be an spacer bearing assembly between the front shaft and the rear shaft of the driveshaft and which provides the mounting the driveshaft to a vehicle, or may also be in the form of a support element having another function which is attached to the shaft close to the movable end of the sleeve at any portion of the driveshaft with the slip stub and the tube sleeve. The bellow may be in the form of a resilient member of a monolithic or segmented structure made of a rubber or synthetic material.

In a preferred embodiment, a cover which is extending radially outwardly from the slip stub covering the roller and having a groove on which the retaining part is mounted. Thus, the cover not only protects the bearing against dust and similar ambient factors, but also allows the bellow to be mounted close to the bearing assembly at one end.

In a preferred embodiment, the cover is having S-shaped cross-section which forms the groove per se. The S-shape provides high structural strength that provides resistance to both axial stresses applied to the groove and radial vibrations from the shaft.

In a preferred embodiment, the retaining part is having a sleeve to engage in the groove from radially inwardly section. The sleeve makes it easy to mount the retaining part securely in the groove on the cover. Alternatively, additional sealing elements or an additional ring to the sleeve may ensure that the holding part is firmly received by the cavity.

In a preferred embodiment, a flange is extending radially outwardly from the sleeve and engaging the bearing assembly in a manner that presses the proximal end. The flange helps to hold the bellow in the cavity after the bellow is installed in the cavity, based on the corresponding end of the bellow from the interior with the fixing element.

In a preferred embodiment of the present invention, the proximal end is having an elbow section bent inwardly towards the flange. The elbow section allows the tubular bellow to be attached to the flange from the inside face. The elbow section can be used in a single piece or in a successive dual structure.

In a preferred embodiment, a cover housing securing the roller is provided on a support element at a vicinity of the roller and into which the cover is mounted. In this way, it is possible to install the cover in the gaps remaining on both sides of the bearing in the support element in which the bearing is located in the bearing assembly.

In a preferred embodiment, the movable end rests against a support wall of the cover in a closed position when the movable end of the tube sleeve is adjacent to the bearing assembly. The support wall stops the axial movement of the tube sleeve in the direction of the bearing assembly. The support wall can be directly integrated in the cover or can be attached to the bearing assembly as a separate part.

In a preferred embodiment, the travel distance is set equal to the stretching distance of the bellow in an open position when the movable end of the tube sleeve is spaced apart from the support wall. Thus, the axial movement of the sliding tool prevents the bellow from being damaged or tear apart.

In a preferred embodiment, the retaining part is made of at least partially by metal. The metal material provides a long-lasting solution against vibrations and other external factors to which the driveshaft will be exposed.

In a preferred embodiment of the invention, the bellow comprises an accordion shaped folding portion. The folding part is provided to be opened at the appropriate distance with the axial advances. With the folding part it is possible to use a compact bellow.

DESCRIPTION OF THE FIGURES

Figure 1 is a front view of a two-piece driveshaft comprising the bellow assembly according to the invention.

Figure 2 is a partial cross-sectional illustration of a sliding assembly comprising a representative embodiment of the bellow assembly.

Figure 3 is an enlarged illustration of the bellow assembly shown in Figure 2. DETAILED DESCRIPTION OF THE INVENTION

In this detailed description, the development according to the invention is explained in no way with any limitation and only with reference to the examples for better illustrating the subject matter.

Figure 1 shows a two-part representative embodiment of the driveshaft according to the invention. The driveshaft comprises a rear shaft (2) with a rear joint (5) and a front shaft (1 ) with a rotary connection by means of a yoke (4). A front joint (3) is provided on the front shaft (1 ), which includes a coaxial coupling. From the gearbox of a vehicle (not shown), the torque applied to the drive train and the coupling assembly is transmitted therefrom via the driveshaft to the rear shaft (not shown) via the rear joint (5).

In Figure 2, a sliding tool on the driveshaft is shown in partial section by being zoomed in on a bearing assembly (20). Above the bearing assembly (20), a roller (24) is supported in a bearing (25) in a radial cavity structure in the middle of a flat upright support element (22).

A slip stub (50) of the sliding tool coaxially passes with the roller (24) through the inner cavity of the roller (24). The suspencion device (209 is suitably mounted from the top of a vehicle chassis base (not shown). A tube sleeve (60) is mounted on the slip stub (50) in an axially movable manner. A space is provided between the tube sleeve (60) and the slip stub (50) to allow movement. A bellow (10) is made of elastic material and is fixed between the tube sleeve 60 and the bearing assembly (20) at its opposite ends. The bellow (10) is attached to the bearing assembly (20) from a proximal end (16) of the tube sleeve (60) proximate the bearing assembly (20), at its opposite distal end (12) it is attached to a corresponding housing in an outer periphery (62) of the tube sleeve (60) by means of a connecting tab (1 1 ) in the form of a radially inwardly extending projection.

The bellow (10) have a folding part (14) of convoluted structure provided between the proximal end (16) and the distal end (12). The folding portion (14) is composed of a plurality of successive radial twisted portions of S-like cross-section close to each other in a folded position of the bellow (10). In the bearing (25) of the roller (24), a cover housing (21 ) is obtained with the distances left by the roller (24) from the edges.

The cover housing (21 ) is closed with a cover (30) that seals the lateral surfaces of the roller (24) in the channel (23) in such a way that the external dirt which will adversely affect the moving parts of the roller (24) does not reach the roller (24) or the bearing (25). The cover (30) is of a bent thin-walled plate structure and has an S-like cross-sectional form. Each cover housing (21 ) is closed by a cover (30), which is positioned in identical form but facing the opposite direction. The cover (30) is a S-shaped radial plate that is bent in the opposite S-shape on the outward-facing portion of the cover housing (21 ) in the portion facing the tube sleeve (60).

The cover (30) comprises a radially outwardly extending exterior edge (32) seated in a short channel (23) extending radially outwardly perpendicular to the bearing (25) on the outside of the support element (22). The cover (30) has a twisted portion at the lower end of the exterior edge (32) which forms a groove (34) which enters the bearing (25). The lower edge of the groove (34) forms a bearing wall (37) formed by a lower wall housing an interior (36) and a lower wall (38) in the opposite direction. The support wall (37) is vertically aligned with the outer edge of the support element (22). The bottom wall (38) sits on the slip stub (50) from the inner face surface.

In Figure 3, the cover (30) is shown partially enlarged. Here, the retaining part (40) secured in the cover (30) is shown as having an L-like cross-sectional form. The retaining part (40), which is hidden in the forming part of the groove (34) of the cover (30), enables the bellow (10) to be secured to the cover (30) from its proximal end (16). At the proximal end (16) of the bellow (10), the bellow (10) are bent radially inward by an elbow section (18). Thus, an inwardly bent rear edge (17) is obtained. The rear edge (17) faces towards the hollow portion of the bellow (10). A form of flange (42) of the retaining part (40) rests against the rear edge (17) from the inside. On the other hand, a portion of the sleeve (44) connected to the flange (42) of the retaining part (40) fits into the interior part (36) by a tight fit. In the meantime, the bellow (10) reaches the closed position by leaning against the support wall (37) from the movable end (64) of the tube sleeve (60).

During operation of the driveshaft, the tube sleeve (60) advances on the slip stub (50). In the meantime, the bellow (10) is opened from the folding part (14) and extends axially. During elongation, the proximal end (16) forms a tension on the flange (42) from its rear edge (17) in the direction of drawing. The flange (42) ensures that the proximal end (169 remains still in the groove (34). The connecting tab (1 1 ) communicates with the outer periphery (62) at the distal end (12) of the bellow (10). Thus, if the movable end (64) of the tube sleeve (60) moves away from the bearing assembly (20) and travels on the slip stub (50), the bellow (30) prevents the entrance of the peripheral foreign elements from the opening of the slide shaft (50) from the slide sleeve (60). When the tube sleeve (60) advances from the movable end (64) towards the cover (30), the movable end (64) rests against the support wall (37). REFERANCE NUMBERS

1 Front Shaft 30 Cover

2 Rear Shaft 32 Exterior Edge

3 Front Joint 34 Groove

4 Yoke 35 Rear Wall

5 Rear Joint 36 Interior Part

10 Bellow 37 Support wall

1 1 Connecting Tab 38 Bottom Wall

12 Distal End 40 Retaining part 14 Folding Part 42 Flange

16 Proximal End 44 Sleeve

17 Rear Edge 50 Slip Stub

18 Elbow section 60 Tube Sleeve

20 Bearing assembly 62 Outer periphery

21 Cover housing 64 Movable End

22 Support Element

23 Channel

24 Roller

25 Bearing