Abstract
The invention relates to a multi-part brake caliper for a vehicle disc brake, the brake caliper comprising: a first part comprising a first portion that is arrangeable at a first side face of a brake disc of the vehicle disc brake; a second part that is formed separately from the first part and comprises a second portion that is arrangeable at a second side face of the brake disc; a middle part connecting the first part and the second part; wherein the middle part is connected to at least one of the first part and second part by a rotational joint.
Claims
1. A multi-part brake caliper for a vehicle disc brake, the brake caliper comprising: a first part comprising a first portion that is arrangeable at a first side face of a brake disc of the vehicle disc brake; a second part that is formed separately from the first part and comprises a second portion that is arrangeable at a second side face of the brake disc; a middle part connecting the first part and the second part; wherein the middle part is connected to at least one of the first part and second part by a rotational joint, the rotational joint comprising: a rounded portion provided at one of the middle part and the respectively connected one of the first part and second part; and a receiving portion receiving the rounded portion and provided at the respective other of the middle part and the respectively connected one of the first part and second part.
2. The brake caliper according to claim 1, wherein the rounded portion comprises at least a spherical segment, in particular wherein the rounded portion comprises an at least half-spherical segment.
3. The brake caliper according to claim 1, wherein the receiving portion is shaped correspondingly to the rounded portion.
4. The brake caliper according to claim 1, wherein the rounded portion is integrally formed with the middle part or wherein the rounded portion is fixed to the middle part.
5. The brake caliper according to claim 1, wherein a rotation axis of the rotational joint extends along at least one of the first portion and the second portion and/or wherein the rotation axis of the rotational joint extends at an angle to a rotation axis of a brake disc of the vehicle disc brake.
6. The brake caliper according to claim 1, wherein a rotation about the rotational joint is limited in at least one direction by a contact between the middle part and the respectively connected first part and second part; and/or wherein a rotation about the rotational joint is enabled in at least one direction by a clearance between the middle part and the respectively connected first part and second part.
7. The brake caliper according to claim 1, wherein the middle part has a side face facing the respectively connected one of the first part and second part, the rounded portion being provided at said side face and said side face being inclined.
8. The brake caliper according to claim 1, further comprising an elastic member that is configured to elastically support the rounded portion when said rounded portion in the receiving portion.
9. The brake caliper according to claim 8, wherein the elastic member is shaped correspondingly to the rounded portion and surrounds at least part of the rounded portion.
10. A method for producing a brake caliper for a vehicle disc brake, the brake caliper comprising: a first part comprising a first portion that is arrangeable at a first side face of a brake disc of the vehicle disc brake; a second part that is formed separately from the first part and comprises a second portion that is arrangeable at a second side face of the disc brake; a middle part for connecting the first part and the second part; the method comprising: connecting the middle part to at least one of the first part and the second part by arranging at least one rounded portion in at least one receiving portion and thereby forming at least one rotational joint, wherein the rounded portion is provided at one of the middle part and the respectively connected one of the first part and the second part and the receiving portion is provided at the respective other of the middle part and respectively connected one of the first part and the second part.
11. The method of claim 10, further comprising: producing at least one of the first part, the second part and the middle part by a production method that is different from a production method of the respective other parts.
Description
BRIEF DESCRIPTION OF DRAWINGS
[0068] Embodiments of the invention are discussed in the following with respect to the attached schematic figures. Similar features may be marked with same reference signs throughout the figures.
[0069] FIG. 1 is a schematic sectional view of a vehicle disc brake according to a prior art solution.
[0070] FIG. 2 is a schematic sectional view of the brake caliper of the vehicle disc brake of FIG. 1 under load.
[0071] FIG. 3 is a schematic side view of a brake caliper according to an embodiment of the invention in a dissembled state.
[0072] FIG. 4 is view of the brake caliper of FIG. 3 in an assembled state.
[0073] FIG. 5 is a schematic side view of a brake caliper according to another embodiment of the invention in a dissembled state.
[0074] FIG. 6 is view of the brake caliper of FIG. 5 in an assembled state.
[0075] FIG. 7 is a detail view of the brake caliper of FIG. 6 when not under load.
[0076] FIG. 8 is a detail view of the brake caliper of FIG. 7 when under load.
[0077] FIG. 9 is a schematic side view of a brake caliper according to an embodiment of the invention in a dissembled state.
[0078] FIG. 10 is a view of the brake caliper of FIG. 9 in an assembled state.
[0079] FIG. 11 is a schematic side view of a brake caliper according to an embodiment of the invention in a dissembled state.
[0080] FIG. 12 is view of the brake caliper of FIG. 10 in an assembled state.
[0081] FIG. 13 is a partial side view of a brake caliper according to another embodiment of the invention when not under load.
[0082] FIG. 14 is a detail view of the brake caliper of FIG. 13 when under load.
[0083] FIG. 15 is another detail view of the brake caliper of FIG. 13 when under load.
[0084] FIG. 16 is schematic side view of a brake caliper according to another embodiment of the invention.
[0085] FIG. 17 is top view of the brake caliper of FIG. 16.
[0086] FIG. 18 is schematic sectional top view of a brake caliper according to another embodiment of the invention.
DETAILED DESCRIPTION
[0087] FIG. 1 shows a prior art vehicle disc brake 1. The vehicle disc brake 1 comprises a brake caliper 2 that is configured as a one-piece casted member. The brake caliper 2 spans across a brake disc 3 that rotates about a rotation axis R (note: only an upper half of the brake disc 3 is depicted in FIG. 1).
[0088] The caliper 2 carries two brake pads 4. Specifically, it carries one brake pad 4 at a first side face of the brake disc 3 (e.g. the left side face in FIG. 1) and another brake pad 4 at a second side face of the brake disc 3 (e.g. the right side face in FIG. 1). For doing so, the caliper 2 comprises a first portion (or finger side) arranged adjacent said first side face and a second portion (or piston side) arranged adjacent said second side face. These portions confine a space or recess 7 for receiving the brake disc 3.
[0089] The brake caliper 2 also comprises a cavity 5 for receiving a brake piston 6 and defining a hydraulic chamber. The brake piston 6 is hydraulically displaceable to contact and press one of the brake pads 4 against the brake disc 3. In a known floating caliper manner, this also forces the opposite second brake pad 4 into contact with the brake disc 3, so that the brake disc 3 is clamped in between the brake pads 4 and thus braked. Upon releasing the hydraulic pressure in the cavity 5, this clamping is released.
[0090] FIG. 2 indicates main concentrations of mechanical stresses occurring in the brake caliper 2 during braking, i.e. when the brake caliper 2 is under load. The region spanning the brake disc 3 and comprised by the below discussed middle part is focused on. At a radially upper side, pressure forces occur (see the upper arrows indicating an orientation of main stresses and pointing towards one another). At a radially lower or inner side, tension forces occur (see the lower arrows indicating an orientation of main stresses and pointing away from one another).
[0091] This uneven distribution of stresses leads to an elastic bending of the caliper 2. Accordingly, an axial distance X between the first portion and second portion of the brake caliper 2 that are provided on different sides of the brake caliper 2 may increase. Specifically, it increases from the initial distance X to X+a, with a being larger than zero. Importantly, in radial direction, the value of the distance increase a may vary, thus leading to the first and second portion changing their relative orientation. This elastic deformation behaviour of the brake caliper under load is accompanied with the above discussed disadvantages.
[0092] The brake calipers according to the below discussed embodiments of the invention may be arranged similarly relative to a brake disc as the brake caliper 1 of FIG. 1. Also, they may carry brake pads in a similar manner in order to arrange them on different sides of the brake disc. Even though not specifically illustrated in the below embodiments, the respective second part in each case comprises a brake actuating mechanism, e.g. identical to the piston 6 received the cavity 5 of FIG. 1.
[0093] On the other hand, in each of the embodiments the brake actuating mechanism could alternatively be provided in the first part or both of the first part and second part could each comprise at least one respective cavity. Also, there may generally be no such cavity 5 or at least no cavity 5 defining a hydraulic chamber. Instead, a vehicle disc brake comprising the brake caliper may e.g. be actuated electrically.
[0094] FIG. 2 shows components of a brake caliper 10 according to an embodiment of the invention in a non-assembled state. The brake caliper 2 comprises a first part 12, a middle part 14 and a second part 16. When viewed along a schematically indicated rotation axis R, these parts (especially in the assembled state, see FIG. 4) form an axial succession with the middle part 14 being axially arranged in between the first part 12 and the second part 16.
[0095] The first part 12 comprises a first portion 13 (e.g. an inner side face) that is arrangeable to face a first side face of a brake disc (not illustrated) and the second part 16 comprises a second portion 17 (e.g. an inner side face) that is configured to face in opposite second side face of the brake disc (not illustrated). The first portion 13 and the second portion 17 thus face one another. They confine at least part of a recess or space in which the brake disc can be received similar to what is depicted in FIG. 1. Also, at each of the first portion 13 and second portion 17, a brake pad can be arranged similar to what is shown in FIG. 1.
[0096] The middle part 14 comprises a rounded portion 18 at both of its axial ends. The rounded portion 18 is ball-shaped and integrally formed with the middle part 14 (e.g. by casting or forging). The rounded portions 18 axially protrude with respect to an axial centre of the middle part 14.
[0097] The first part 12 and the second part 16 both comprise a receiving portion 20. Each receiving portion 20 is formed as a recess or cavity. Its shape and, more precisely, the shape of its inner surface matches a shape of an outer surface of the rounded portions 18. As indicated in FIG. 4, this way each receiving portion 20 is configured to receive and at least partially surround one of the rounded portions 18 to define a form fit therewith. Also, a force fit may be produced to arrange the first part 12, the middle part 14 and the second 16 in a defined manner relative to one another and to maintain said relative orientation.
[0098] Arranging the rounded portions 18 in the receiving portions 20 may include temporarily elastically widening the receiving portions 20. Alternatively, the receiving portion 20 may be defined by at least two sub-parts comprised by the first part 12 and second part 16 that may be temporarily detached from one another to receive the rounded portions 18 in between them. An optional divisional plane D for dividing the first part 12 and the second 16 extends orthogonally to the image plane of FIG. 3 and is indicated with a dotted line. In general, once received in the receiving portion 20, the rounded portion 18 cannot easily be removed or pulled out of the receiving portion 20 during normal brake operation.
[0099] By receiving a rounded portion 18 in a receiving portion 20 a rotational joint 22 is defined. Its (e.g. main) rotation axis J extends orthogonally to the image plane and through a centre of the rounded portion 20.
[0100] The rotational joints 22 are positioned so as to overlap or be axially adjacent to with an axial position of first portion 13 of the first part 14 and second portion 17 of the second part 16. They are positioned in regions in which the shape of the caliper 10 changes from extending along a side face of the brake disc 12 to spanning across the brake disc 12. Put differently, the rotational joints 22 are provided in corner portions or angled portions of the caliper 10. These corner or angled portions are each provided at and/or each comprise an axial outer edge of the middle part 16. Note that this position of the rotational joints 22 in or at an inlet portion is not limited to the depicted embodiment or its further specifics, but may be a general feature of any embodiment disclosed herein.
[0101] In FIG. 4, it can be seen that the middle part 14 and the respectively connected first part 12 and second part 16 contact one another in edge regions surrounding the rounded portions 18 and receiving portions 20, respectively. This contact limits an amount of rotation about the rotational axes J. The contact is formed at both of a radially upper and lower side of the rounded portion 18 (e.g. radially above and below of the centre of the rounded portion 18).
[0102] A first advantage of the embodiment according to FIGS. 3 and 4 is the configuration of the brake caliper 2 is a multipart member. More precisely, the first part 12, the middle part 14 and second part 16 the can be produced independently from one another and even by generically different production methods. This allows for an individual optimisation of each part, e.g. in terms of costs and/or rigidity without being severely restricted by boundary conditions concerning the respective other parts 12, 14, 16. For example, the first part 12 may be a non-casted part (e.g. produced by metallic shaping), whereas the second part 16 may be a metal-cast part. The middle part 14 may comprise a layer of sheet metals or may be welded from different parts. On the other hand, even if producing each part 12, 14, 16 with the generically same production method (e.g. casting) they can still be individually optimized (e.g. in terms of shapes or dimensions) which can bring about improvements compared to existing one-piece designs.
[0103] Another advantage concerns of the elastic deformation behaviour. The mechanical stresses occurring under load are generally similar to FIG. 2. By way of the rotational joints 22, a rotational degree of freedom is introduced which, however, is limited by the contact between the middle part 14 and each of the first part 12 and second part 16. Yet, given that this contact is formed on both a radially upper and lower side of the rounded portion 18, and due to the expected extents of the mechanical stresses at the radially upper end lower side of the middle part 14 (see FIG. 2) and the resulting deformations, it has been determined that a slight rotation about the rotational axis J can occur that may limit the increase in axial distance marked a in FIG. 2. Also, the rotation may at least dissipate some of the mechanical energy associated with the stresses, thus further limiting the increase in axial distance a.
[0104] FIGS. 5 and 6 show a brake caliper 10 according to further embodiment. FIG. 5 shows a disassembled state, whereas FIG. 6 shows an assembled state. The caliper 10 again comprises a first part 12 a middle part 14 and a second part 16 that are arranged and oriented relative to one another in the same manner as in the first embodiment. A difference compared to the first embodiment concerns the design of the middle part 14. Specifically, the side faces 15 of said middle part 14 which face the respectively adjacent first part 12 and second part 16 are inclined. More precisely, they are tilted towards the respectively adjacent first part 12 and second part 16.
[0105] At the side faces 15, the rounded portions 18 are provided. Merely as an example, these are configured as spheres that are connected to the side faces 15 by a web section 21. The first part 12 and the second part 16 again comprise receiving portions 20 shaped similar to the rounded portions 18. The inclination of the side face 15 is chosen to define different radially upper and lower axial clearances C1 and C2 indicated in FIG. 6. Additionally or alternatively, this difference in clearances C1, C2 can be defined by adjusting the (local) axial width and/or the (local) inclination of inner faces 19 of the first part 12 and the second part 16 that face the respectively inclined side face 15 of the middle part 14.
[0106] As visible in FIG. 6, the radially upper clearance C1 is smaller than the radially lower clearances C2 (e.g. is at most half as large). This means that an angular range of a possible clockwise rotation of the first part 12 towards the middle part 14 is smaller (i.e. is limited to the angular range of the clearance C1) than a rotation in a counter-clockwise direction that corresponds to the angular range of the clearances C2. With regard to the second part 16, a counter-clockwise rotation towards the middle part 14 is equally more limited (i.e. defined by the smaller clearance C1) compared to an opposite clockwise rotation.
[0107] In reaction to the mechanical stresses occurring under load and explained with respect to FIG. 2, this means that the increase a in the axial distance X and in particular its local variations can be limited. This is because a tilting movement of the first and second portions 13, 17 away from one another is restricted.
[0108] FIGS. 7 and 8 show an alternative configuration of the embodiment of FIGS. 5 and 6. These Figures only depict the first part 12 and part of the middle part 14. Yet, an identical configuration may be provided between the middle part 14 and the second part 16. The shape and/or inclination of the side face 15 and/or the opposite inner faces 19 of the first part 12 are chosen so that the radially upper clearances C1 is zero. This already occurs when not under load. The radially lower clearances C2, on the other hand, is present already when not under load and e.g. amounts to not more than 2 mm, e.g. between 0.2 and 0.5 mm. Note that the clearance C2 of FIGS. 5 and 6 may have similar dimensions.
[0109] FIG. 8 shows the brake caliper 10 of FIG. 7 when under load. Load is caused by a reaction force indicated by an arrow and resulting from pressing the brake pad against the brake disc during braking (not illustrated). It is shown that the lower clearance C2 is significantly reduced and may e.g. be reduced to 0, while the upper clearance C1 remains zero at an increased contact pressure. This results from the tension forces occurring in the radially lower section of the middle part 14 (see FIG. 2). Reducing the clearance C2 accordingly may be supported by the rotational joint 20 which supports a respective deformation of the radially lower part of the middle part 14 under load. At the same time, this means that the mechanical stresses occurring under load are at least partially dissipated by said rotational movement, thereby limiting an increase in the axial distance a (see FIG. 2).
[0110] FIGS. 9-12 show embodiments that are comparable to those of FIGS. 3-4, but further include an elastic member 30 in each of the rotational joints 22. FIGS. 9 and 10 correspond to the embodiment of FIGS. 3 and 4 in which the middle part 14 is integrally formed with its rounded portions 18. FIGS. 11 and 12 show a different configuration in which the rounded portions are mechanically connected to the middle part 14, e.g. by a screw connection forming a web section 21.
[0111] The elastic members 30 are formed as elastic rings or as at least part-spherical members having an opening 32 in order to receive the rounded portions 18.
[0112] The elastic members 30, as depicted in FIGS. 10 and 12, are arranged in between the rounded portions 18 and the receiving portions 20, thereby acting as elastic intermediate members. The rounded portions 18 and receiving portions do not directly contact one another, but may be separated from one another by a respective elastic member 30.
[0113] FIGS. 13-15 show a deformation of the elastic member 30 under load. The figures are based on the configuration of FIG. 12. FIG. 13 shows a part of FIG. 12 in a state where the brake caliper 12 is not under (mechanical) load. FIG. 15 is a view similar to FIG. 13 with the brake caliper 12 being under load. FIG. 14 is an enlarged view of the elastic member in the loaded state of FIG. 15. In FIG. 13, the direct contact between the middle part 14 and first part 12 is shown. A clearance C is zero, even when not under load.
[0114] In FIG. 15, the lower arrow marks a reaction force occurring during braking. The upper curved arrow indicates that the first part 12 may in reaction slightly rotate about the rotational joint 22 relative to the middle part 14 while deforming the elastic member 30. As shown in FIG. 14, this may result in the rounded portion 18 no longer being concentrically arranged in the receiving portion (as previously the case in the non-braking state). Also, this may result in a contact pressure between the first part 12 and middle part 14 increasing at the upper reference sign C and decreasing at the lower reference sign C.
[0115] The deformation of the elastic member 30 is an additional means to dissipate at least part of the mechanical stresses. Also, it may act as a dampening element to limit vibrations. Further, its deformation may at least partially compensate for deformations of the first part 12 and second part 14, thereby limiting an increase a of the axial distance (or at least its local variations) as explained with respect to FIG. 2.
[0116] FIGS. 16 (top view) and 17 (side view) indicate possible distributions of rotational joints 22 within a brake caliper 10 according to a further embodiment. The middle part 14 is fixed to at least one (and in the shown case to both) of the first part 12 and second part 16 by a plurality of rotational joints 22. Each rotational joint 22 comprises one spherical rounded member 18. Optionally, each rotational joint 22 may comprise an elastic member 30 of the above-explained type. FIGS. 16 and 17 are highly schematic and maily serve to illustrate positions of the rotational joints 22. It should be understood that the rotational joints 22 may not be visible from outside and housed with the parts 12, 14, 16 of the brake caliper 10.
[0117] FIG. 18 shows a top view of a brake caliper 10 according to an alternative embodiment. In this case, the elastic member 30 is elongated. A horizontal sectional plane is positioned so that this elastic member 30 is visible. Specifically, it is formed with a C-shaped cross-section (see FIG. 9) and extending along the width of the brake caliper 10. The (non-depicted) receiving portion 20 may also extend with a similar cross-section along said width and receive the elastic member 30. The rounded portion 18 that is obstructed by the elastic member 30 may define a hinge with a similar cross-section shape as depicted in e.g. FIG. 3 and may be elongated along the width of the brake caliper 10 as well.
