The invention relates to a brake caliper for a vehicle disc brake, in particular, an air disc brake of a commercial vehicle, the brake disc having a pair of brake pads, and a disc positioned in between the brake pads, the brake caliper com- prising: a thrust piece movably mounted in an axial direction in the brake cali- per, wherein the thrust piece is configured to move at least one of the brake pads relative to the disc, an adjuster unit in threaded engagement with the thrust piece, and a spring unit operatively coupled to the adjuster unit and the thrust piece and configured to apply a spring force in the axial direction between the thrust piece and the adjuster unit.

Brake calipers for vehicle brakes of the aforementioned type are generally known in the art and typically employed in trucks, busses and bikes. Upon re- ceiving an actuation signal, for example, from a brake pedal in the driver cabin or from an electronic control unit, a braking force is generated by a brake cylin- der and transmitted to the brake caliper and the thrust piece. In common brake calipers, the thrust piece is part of a clamping unit which is configured to ad- vance the brake pad. After overcoming an air clearance between the brake pads and the brake disc, a frictional force is applied by an inner brake pad ad- vanced by the thrust piece to the rotating brake disc of the brake. At the same time, a frictional force is applied by an outer brake pad advanced by the brake caliper to the brake disc.

In known brake calipers an adjuster unit is used to control the air clearance or air gap between the pair of brake pads and the brake disc.

In common brake calipers of the aforementioned type, a disc spring is opera- tively coupled to the adjuster unit and the thrust piece to eliminate or at least minimize the play between the thrust piece and the adjuster unit. Additionally, a retaining ring engaging the thrust piece is used to provide a turning resistance between the thrust piece and the adjuster unit. Such a retaining ring, for exam- ple, has a number of bores configured to receive screws in order to couple the retaining ring with a thrust piece.

While those disc springs and additional retaining rings provided a sufficient turn- ing resistance and at least minimized the play between the thrust piece and the adjuster unit sufficiently, they were complex to assemble. In seldom cases where failure of either the disc spring or the retaining ring would occur, said fail- ure could result in a failure of the whole assembly.

Therefore, it was an object of the present invention to suggest a brake caliper that overcomes the disadvantages mentioned above as much as possible or to provide at least an alternative to the known solutions. In particular, it was an object to provide a brake caliper with simplified assembly and a higher reliabil- ity, preferably without deteriorating cost efficiency.

The invention attains the aforementioned object by suggesting a brake caliper according to claim 1 . In particular, the invention suggests that the spring unit has a latching element and the adjuster unit has a corresponding latching inter- face, wherein the latching element is arranged to engage the latching interface when the adjuster unit is in threaded engagement with the thrust piece, and in that, the spring unit further has a mounting element in engagement with the thrust piece to provide a resistance against a rotational movement the adjuster unit relative to the thrust piece.

The invention is based upon the realization that by having the spring unit elimi- nate or at least decrease the play between the adjuster unit and the thrust piece and at the same time provide a resistance against rotation, two functions can be combined while at the same time, reliability may be increased, manufacturing costs are reduced and the assembly is simplified already due to a reduction of the number of components required for performing said functions. As the spring unit only engages the adjuster unit when the adjuster unit is in threaded engagement with the thrust piece, the assembly of thrust piece and the adjuster unit is not impeded.

Preferably, the spring unit is coaxially arranged to the adjuster unit and has a central annular aperture receiving the adjuster unit at least partly. Thus, the spring unit is easy to orientate and arrange with respect to the adjuster unit.

In a preferred embodiment, the spring unit has a ring portion that is conically- shaped and extends radially outwards from the central annular aperture. Such a ring portion has an axial extension between an inner circumference defined by the central annular aperture and an outer circumference provided at a front end facing and engaging the thrust piece. Preferably, the ring portion is resiliently deformable and configured to apply a spring force in the axial direction between the thrust piece and the adjuster unit.

In a further preferred embodiment, the latching element is a first latching ele- ment engaging the latching interface at least partly and the spring unit further comprises at least one second latching element that is arranged spaced apart from the first latching element in a circumferential direction, wherein the second latching element engages the latching interface at least partly. Thus, by having at least two, preferably three or more latching elements, the reliability is in- creased as in the case of failure of one latching element, one or more further latching elements will still engage the latching interface thereby ensuring the functionality.

Preferably, the latching interface is formed as an external thread extending in axial direction and having a number of thread pitches, and wherein the latching element is arranged to engage one of the thread pitches. Thus, the latching in- terface can preferably be provided by the same thread engaging the thrust piece in threaded engagement. Thus, the assembly is simplified and the manu- facturing costs are reduced. Further, by engaging an external thread, a good accessibility is provided for the latching elements to engage one of the thread pitches. In a preferred embodiment, the adjuster unit has an adjuster screw in threaded engagement with the thrust piece, and wherein the thread forming the latching interface is formed as an external thread of the adjuster screw. Such an adjust- er unit provided an easy to manufacture part to couple the adjuster unit and the thrust piece in threaded engagement.

Preferably, the latching element has a curved surface that corresponds to the curvature of one of the thread pitches. By suggesting that the latching element has a curved surface that corresponds to the curvature of the thread pitch, the invention advantageously recognizes that the spring forces applied by the spring unit are more evenly distributed when transmitted by a curved surface corresponding to the curvature of the thread pitches.

Further preferred, the latching element extends radially inwards and comprises a front edge facing the external thread, wherein the front edge is configured for being at least partly received in the thread pitch. Thus, during assembly of the thrust piece and the adjuster unit and bringing the adjuster unit and the thrust piece in a threaded engagement, the latching element is resiliently deformed radially outwards and when the thrust piece and the adjuster unit have been brought into threaded engagement, the latching element will resiliently deform radially inwards again such that the front edge of the latching element is at least partly received in the thread pitch, thereby engaging the thread pitch.

Preferably, the first latching element engages a first thread pitch and the second latching element engages a second thread pitch. Thus, the forces acting be- tween the latching element and the latching interface are more evenly distribut- ed.

In a further preferred embodiment, the thrust piece has a mounting interface corresponding to the mounting element, wherein the mounting interface engag- es the mounting element in a positive connection. By having a mounting inter- face, and a corresponding mounting element in a positive connection, the as- sembling of the thrust piece and the spring unit is simplified. Preferably, the mounting interface is configured to engage the mounting ele- ment upon an axial movement of the spring unit towards the thrust piece. Thus, the spring unit and the thrust piece are easy to assemble, simply by moving the spring unit towards the thrust piece, wherein the adjuster unit is sufficiently se- cured against a rotational movement relative to the thrust piece.

Further preferred, the mounting element is extending radially outwards, and the mounting interface is formed to receive the mounting element at least partly. By suggesting that the mounting element is extending radially outwards, the loca- tion of engagement of the mounting element and the mounting interface is spaced apart from the engagement of the latching element and the latching in- terface. Thus, the engagement between the spring unit and the thrust piece does not impede the engagement of the spring unit and the adjuster unit.

Particularly preferred, the thrust piece has a recess corresponding to the spring unit and configured to receive the spring unit at least partly. Thus, the orienta- tion and arrangement of the spring unit relative to the thrust piece is simplified.

Hereinabove, the invention has been described in a first aspect with respect to a brake caliper.

In a second aspect, the invention also relates to a spring unit for a brake caliper of a vehicle disc brake, preferably a brake caliper according to the preferred embodiments of the invention described above, wherein the spring unit is con- figured to be operatively coupled to an adjuster unit and a thrust piece of the brake caliper and configured to apply a spring force in an axial direction be- tween the thrust piece and the adjuster unit.

According to the second aspect, the invention achieves the initially mentioned object in that the spring unit further has a latching element arranged to engage a latching interface of the adjuster unit when the adjuster unit is in threaded en- gagement with a thrust piece, and in that the spring unit further has a mounting element configured to be in engagement with the thrust piece to provide a re- sistance against a rotational movement the adjuster unit relative to the thrust piece. The benefits and preferred embodiments of the brake caliper of the first aspect as described above are also the preferred embodiments and benefits of the spring unit of the second aspect and vice versa.

For a more complete understanding of the invention, the invention will now be described in detail with reference to the accompanying drawing. The detailed description will illustrate and describe what is considered as a preferred embod- iment of the invention. It should of course be understood that various modifica- tions and changes in form or detail could readily be made without departing from the spirit of the invention. It is therefore intended that the invention may not be limited to the exact form and detail shown and described herein, nor to any- thing less than the whole of the invention disclosed herein and as claimed here- inafter. Further, the features described in the description, the drawings and the claims disclosing the invention may be essential for the invention considered alone or in combination. In particular, any reference signs in the claims shall not be construed as limiting the scope of the invention. The wording “comprising” does not exclude other elements or steps. The wording “a” or “an” does not ex- clude a plurality.

This invention will now be described with reference to the accompanying draw- ings which illustrate, by way of example and not by way of limitation, one of several possible embodiments of the vehicle disc brake proposed herein, and wherein

Fig. 1 : schematically illustrates a brake caliper in a sectional view,

Fig. 2: schematically illustrates a part of the brake caliper, according to

Fig. 1 in a perspective view,

Fig. 3: schematically illustrates a part of the brake caliper in a sectional view, according to Fig. 1 ,

Fig. 4: illustrates a part of the brake caliper, according to Fig. 1 , in a part-sectional side view,

Fig. 5: illustrates a spring unit for the brake caliper, according to Fig. 1 , in a top view, Fig. 6: illustrates the spring unit, according to Fig. 4, in a perspective view.

Fig. 1 illustrates a vehicle brake 1 having a brake caliper 10, a pair of brake pads 20a, b and a brake disc 30 arranged in between the brake pads 20a, 20b.

The brake caliper 10 comprises a clamping unit 100, an adjuster unit 200 and a spring unit 300.

The inner brake pad 20a is operatively coupled to the clamping unit 100. At least a part of the clamping unit 100 is in engagement with the adjuster unit 200. The spring unit 300 is operatively coupled to the adjuster unit 200 and the clamping unit 100.

Figs. 2 to 4 illustrate the clamping unit 100, the adjuster unit 200 and the spring unit 300 in an assembled state.

Fig. 2 illustrates the clamping unit 100 in a perspective view. The clamping unit 100 comprises a thrust piece 110 configured to be movably mounted in the brake caliper 10 (see Fig. 1), the adjuster unit 200 being in threaded engage- ment with the thrust piece 110, and the spring unit 300 being operatively cou- pled to the adjuster unit 200 and the thrust piece 110 and configured to apply a spring force in an axial direction A between the thrust piece 110 and the adjust- er unit 200.

The spring unit 300 is coaxially arranged to the adjuster unit 200.

The thrust piece 110 has a mounting interface 112 engaging the spring unit 300 in a positive connection, and a recess 114 corresponding to the spring unit 300 and receiving the spring unit 300 at least partly.

The adjuster unit 200 has an adjuster screw 210 in threaded engagement with the thrust piece 110. As best shown in Fig. 3, the adjuster unit 200 further has a latching interface 220 that is formed as an external thread of the adjuster screw 210. The latching interface 220 is extending in the axial direction A.

As shown in Figs. 3 and 4, the latching interface 220 has a first thread pitch 221 and a second thread pitch 222 engaged by the spring unit 300.

The adjuster screw 210 is partly received in the thrust piece 110 such that the latching interface 220 is in threaded engagement with an internal thread of the thrust piece 110.

As shown in Fig. 2, the spring unit 300 has a first latching element 310, a sec- ond latching element 320 and a third latching element 330 configured to engage the latching interface 220.

The spring unit 300 further has a mounting element 340 in engagement with the mounting interface 112 of the thrust piece 110.

The spring unit 300 further has a ring portion 350 extending radially outwards from a central annular aperture 360 (see Figs. 5 and 6).

The mounting element 340 is extending radially outwards from the outer circum- ference of the ring portion 350.

As best shown in Fig. 3, the first latching element 310 engages a first thread pitch 221 of the latching interface 220. The second latching element 320 is en- gaging a second thread pitch 222 of the latching interface 220.

As this becomes apparent from Figs. 3 and 4, the outer circumference of the ring portion 350 (see Figs. 5 and 6) rests against the thrust piece 110 and is supported by recess 114. In particular, the spring unit 300 is supported in the radial direction by an inner circumferential side wall 114a of the recess 114 and in the axial direction A by a bottom surface 114b of the recess 114.

Figs. 5 and 6 illustrate the spring unit 300 having the latching elements 310, 320 and 330. The spring unit 300 further has the central annular aperture 360 configured to receive the adjuster unit 200 at least partly.

The mounting element 340 is extending radially outwards from the outer circum- ference of the ring portion 350.

The spring unit 300 further has the ring portion 350 extending radially outwards from the central annular aperture 360.

The latching elements 310, 320, 330 are extending radially inwards from the ring portion 350. Each of the latching elements 310, 320, 330 has a curved sur- face 311 , 321 , 331 with a front edge 312, 322, 332, wherein the front edge 312, 322, 332 is received in a corresponding thread pitch when engaging the latching interface 220 (see Fig.3) of the adjuster unit 200 (see Fig. 2).

Each of the curved surfaces 311 , 321 , 331 is formed corresponding to the cur- vature of one of the thread pitches such that the latching elements 310, 320,

330 engage the corresponding thread pitch.

Reference signs (part of specification)

1 vehicle brake

10 brake caliper

20a, b brake pads 30 brake disc 100 clamping unit 110 thrust piece 112 mounting interface 114 recess 114a side wall, recess 114b bottom surface, recess 200 adjuster unit 210 adjuster screw 220 latching interface, 221 first thread pitch 222 second thread pitch 300 spring unit

310 first latching element

311 curved surface

312 front edge

320 second latching element

321 curved surface

322 front edge

330 third latching element

331 curved surface

332 front edge 340 mounting element 350 ring portion 360 central annular aperture A axial direction