GB2131507A

GB2131507A - Brake caliper housing

Info

Publication number: GB2131507A
Application number: GB08330564A
Authority: GB
Inventors: Jochen Burgdorf; Rudolf Thiel
Original assignee: Alfred Teves GmbH
Current assignee: Continental Teves AG and Co oHG
Priority date: 1982-12-07
Filing date: 1983-11-16
Publication date: 1984-06-20
Also published as: FR2537229B1; IT1194509B; GB8330564D0; DE3245157A1; GB2131507B; IT8324089A0; FR2537229A1; JPS59113328A

Abstract

A brake caliper housing, in particular for a spot-type disc brake of an automotive vehicle, comprises at least two housing parts (188, 190) which having already been machined, are welded together. As shown, the housing parts are caliper limbs (28, 36) with e.g. welding seem (198) or (196) at right angles or parallel to longitudinal axis of housing. In alternative embodiments, a guide bolt is welded in a bore in a brake caliper (Fig. 6), a cylinder cover is welded in a cylinder bore (Figures 9-14); a pressure plate is welded to a radial housing part (Figure 15). Welding may be electron-beam or laser. Materials of the housing parts are indicated e.g. cast iron, steel, aluminium. <IMAGE>

Description

SPECIFICATION Brake caliper housing The present invention is concerned with a brake caliper housing in particular for a spot-type disc brake of a vehicle, of the kind comprising at least two housing parts which are interconnected.

A brake caliper housing of this kind is known from German printed and published patent application 27 10 511. In this brake caliper housing a first housing part constitutes a radially extending limb which contains a brake cylinder and an axially tangentially extending bridge portion. A second housing part forms a second radial limb which is arranged opposite the first radial limb. The parting plane between the two housing parts extends at right angles to the axis of the brake cylinder. The two housing parts are held together by bolts.

Even though this known brake caliper housing already offers the advantage resulting from the division into two parts, namely that the cylinder bore can be made from the side of the brake disc without the radial limb arranged opposite to it requiring to be furnished with a respective qpening, the known housing does however not permit its being manufactured in an optimum manner as far as its weight is concerned on account of the bolts by which the housing parts are coupled. In addition, this housing does not allow for a radial extraction of the brake shoes.

It is, therefore, an object of the present invention to improve the known brake caliper housing in such a manner as to realise a better solution with regard to weight, space and ease of manufacture.

According to one aspect of the invention, there is provided a brake caliper housing in particular for a spot-type disc brake of an automotive vehicle, of the kind comprising at least two housing parts which are interconnected, characterised in that the already machined housing parts (188, 190) are welded together.

According to another aspect of the invention, there is provided a method of manufacturing a brake caliper housing in particular for a spot-type floating caliper vehicle brake, with at least two of the said housing limbs forming the housing being manufactured as blanks and being substantially already machined, characterised in that the already machined housing limbs are welded together.

In this way, connecting elements, such as bolts, which lead to an increase in weight are avoided. Since connecting elements of this kind also require space, the invention also offers an advantage in this regard. Finally, manufacture and assembly are also facilitated. In particular, those housings which permit a change of pads in a radial direction do not require reaming. Holes in the external radial housing limb need not be provided, so avoiding impairing the stiffness of that limb.

According to an advantageous embodiment of the invention which provides a housing with a first radial housing limb that is furnished with a cylinder bore for accommodation of a piston, a second radial housing limb, and a bridge portion which connects the radial housing limbs it is envisaged to locate the welded joint at the point of transition from the bridge portion of the first housing limb which contains the cylinder bore. It is also of advantage to locate the welded joint at the point of transition from the bridge portion to the second radial housing limb. In both cases the housing parts to be connected to each other are formed with joint faces extending at right angles to the longitudinal axis of the housing. In the second case the housing parts connected to each other can alternatively be provided with joint faces running parallel with the longitudinal axis of the housing.

In another embodiment, an axial cylinder bore provided in a first radial housing limb is configured as a through bore and is covered by a lid which is welded to the radial housing limb. An advantageous further improvement consists in the cylinder bore being formed with a radial enlargement at its internal end facing away from the bridge portion, in the cover lid being inserted in the elargement and in the welding seam connecting the peripheral surface of the cover lid with the inner circumferential surface of the enlargement, the welding seam being axially directed against material of the housing which surrounds the cylinder bore.

Another version is expedient in which the cover lid is seated on the front side of the housing limb comprising the cylinder and in which the welding seam is located at the circumference of that part of the housing limb which forms the cylinder. In this version, the cover lid is advantageously formed with an axially extending outer collar and the housing limb surrounding the cylinder bore has an external annular recess into which engages the collar of the cover lid so that joint faces extending at right angles to the longitudinal axis of the cylinder are formed which are bonded by a welding seam.

Still other advantageous embodiments result from the housing parts connected to each other being made of different materials. In particular, the housing part containing the cylinder is advantageously made of nodular cast iron, cast aluminium, die-cast aluminium or forged aluminium. The housing part containing the bridge portion is advantageously made of nodular cast iron, forged steel, cast aluminium, forged aluminium or die-cast aluminium. Combinations of these materials can be selected to advantage as the specific case may be.

The method according to the second aspect of the invention results in substantial advantages for the manufacture of the brake caliper housing. In particular, these consist in a simplified manufacture and in improved properties of the housing as already specified above.

In advantageous embodiments of the inventive method it is envisaged that the welded joint is made by electron-beam welding or by laser welding.

The housing parts to be connected are expediently provided with joint faces extending at right angles to the longitudinal axis of the housing.

Another advantageous embodiment covers a method by which the cylinder cover, too, is welded into the cylinder bore.

According to this solution, first the cylinder bore is enlarged at its internal end, then the cover lid is inserted in the enlargement, and the weld made at the internal front side of the housing part comprising the cylinder.

In another embodiment of the method the cover lid may, as an alternative, be seated on the front side of the housing limb comprising the cylinder and the weld be made at the circumference of that housing part comprising the cylinder.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a front view of a spot-type disc brake; Figure 2 is a plan view of a spot-type disc brake shown in Figure 1; Figure 3 is a cross-section through the spottype disc brake along the line A-A in Figure 1; Figure 4 is a partial cross-section through the spot-type disc brake along the line B-B in Figure 1; Figure 5 is a front view of the housing of the spot-type disc brake illustrated in Figures 1 to 4; Figure 6 is a plan view, partly in section, of the housing of the spot-type disc brake as per Figure 5; Figure 7 is a longitudinal 'section through a diagrammatically illustrated housing of a spottype disc brake; Figure 8 is a plan view of the housing as shown in Figure 7;; Figure 9 is the longitudinal section of another embodiment of the housimg of a spot-type disc brake; Figure 10 is a partial sectional view of a cylinder closed by a cover lid; Figure 11 is another embodiment of a cylinder closed by a cover lid; Figure 12 is a further embodiment of a cylinder closed by a cover lid; Figure 13 is a third embodiment of a cylinder closed by a cover lid; Figure 14 is a fourth embodiment of a cylinder closed by a cover lid; Figure 1 5 is the cross-section of a further embodiment of a brake caliper housing.

Reference is made first of all to Figures 1 to 6 which show a complete spot-type disc brake that utilises the invention.

The spot-type disc brake illustrated in Figures 1 to 6 is intended for installation in an automative vehicle. It comprises a brake carrier 2 which is boltable to a steering knuckle, to the axle or to another structural member of the wheel suspension of the vehicle at the side of a brake disc 8 by means of fastening eyes 4, 6. The brake carrier 2 is formed with two brake carrier arms 10, 1 2 arranged tangentially at a distance from each other in a substantially V-shaped configuration, which brake carrier arms 10, 12 are furnished with bores 14, 1 6 at their radially external ends. The bore 14 in the brake carrier arm 10 is arranged in an axially extending attachment 18 at the external end of the brake carrier arm 10.As will be described in more detail later, the bore 14 axially slidably receives a guide bolt 22 which is fitted to a brake caliper 20. In the bore 1 6 of the brake carrier arm 12 is fixed an axially extending guide pin 24 which is arranged in an axially slidable manner in an axially-oriented bore 26 in the brake caliper 20, which will again be explained in more detail later.

The brake caliper 20 is substantially shellshaped and comprises a first radially-extending limb 28 which forms a brake cylinder 30 that receives a brake piston (not shown). The limb 28 is succeeded by a bridge portion 34 extending substantially in axial and circumferential directions which bridge portion 34 straddies the brake disc 8. On the other side the bridge portion 34 merges into a further radially-extending limb 36. Beside the brake cylinder 30 in the limb 28, there is provided an axially extending bore 38 in which the guide bolt 22 is fixed which also extends axially. As already outlined above, the guide bolt 22, with its free end projecting from the bore 38, engages the bore 14 of the brake carrier arm 10 and is axially slidable therein.The diameters of the guide bolt 22 and of the bore 14 are harmonised with each other in such a manner that the guide bolt 22 forms a fixed bearing with the bore 14. The free end of the guide pin 24 secured in the brake carrier arm 10 penetrates through a bore 40 which is provided in the brake caliper 20 on the other side of the brake cylinder 30. In this context, the guide pin 24 is of smaller diameter than the bore 1 6 so that a circular ringshaped gap 42 is formed between the guide pin 24 and the bore 1 6 and the guide pin 24 is radially and tangentially movable in the said gap.

For damping of these movements, an elastic sleeve 44 which may, for example by made of rubber is inserted in the bore 40 located in the brake caliper 20. The elastic sleeve 44 has substantially cylindrical shape and is formed at its external circumference with an annular protuberance 46 which engages a correspondingly shaped annular groove 48 in the bore 40 so that the elastic sleeve 44 is retained in the bore 40.

Thanks to the arrangement described of the guide bolt 22, of the guide pin 24 and of the pertaining bores, the brake caliper 20 is axiallyslidably supported at the brake carrier 2, with the guide bolt 22, as already outlined above, forming a fixed bearing with the bore 38 and the guide pin 24 forming a moving bearing with the bore 40.

In the brake carrier 2, there is formed a guide 50 which presents two abutment faces 52, 54 which are parallel with each other and arranged at a distance in a peripheral direction and in between which abutment faces 52, 54 an internal brake shoe 56 is guided with its back plate 58. An identical guide 60 is provided on the opposite side of the brake disc 8 in the limb 36 of the brake caliper 20. This guide 60, too, comprises two abutment faces 62, 64 in between which an external brake shoe 66 with its back plate 68 is arranged. In the bridge portion 34 of the brake caliper 20, there is provided a substantially rectangular through opening 70 which affords access to the brake shoes 56, 66. Through that opening 70, the brake shoes 56, 66 can be easily inserted in their guides 50, 60 or be removed from these guides in a radial direction.

For securing the brake shoes 56, 66, their back plates 58, 68 are furnished with oblong through openings on either side, of which only one opening in each case, designated 72 or 74, is shown in Figure 2. Axially extending pad retaining pins 76, 78 pass through these openings 72, 74.

The pad retaining pins 76, 78 are seated in opposed bores 80, 82 in the brake caliper 20. In this context, the pad retaining pins 76, 78 are secured by a deformable barrel-shaped element 84 which is located at their internal ends and by means of which the pad retaining pin 76 is clamped in the bore 80.In addition, pad retaining springs 86, 88 are provided which have a substantially H-shaped configuration and extend parallel with the brake shoes 56, 66. Those stems 90, 92, 94, 96 of the pad retaining springs which face the brake disc 8 are longer than the stems 98, 100, 102, and 104 facing away from the brake disc and they reach under the pad retaining pins 76, 78. Centre webs 106, 108 of the pad retaining springs 86, 88 rest on the upper sides of the back plates 58, 68 and the shorter stems 98, 100, 102, and 104 abut against the rear sides of the back plates 58, 68.

The guide bolt 22 comprises a fastening portion 110 and a guide portion 112. The fastening portion 110 is seated in the bore 40 in the brake caliper 20 and is welded to it. The welding seam is applied by an electron-beam welding process which unites the surfaces of the guide bolt 22 and of the bore 40 which are in contact with each other. In order to reduce the weight, a central recess 114 closed by means of a plastic plug 116 is provided in the fastening portion 110. The transition from the fastening portion 110 to the guide portion 112 is formed with a curvature 118 in order to avoid notch strains. An annular groove 120 is provided in the guide portion for accommodation of the inner end of a rubber boot 122 which is fixed with its outer end 124 on a circular circumferential surface of the axial attachment 18 by means of a ring 126.

The guide portion 112 is furnished with a spiralshaped lubricating groove 1 28.

As is clear from Figures 6 and 9 in particular, the brake cylinder 30 has a cylinder through bore 130 which is closed by a cylinder cover 132. The cylinder cover is fitted in an enlargement 134 of the cylinder bore and abuts against a shoulder 1 36 that is formed between the cylinder bore 130 proper and the enlargement 134. The bond between the cylinder cover 1 32 and the brake cylinder 30 is carried out by electron beam welding, with this welded joint S-S connecting the peripheral surface of the cylinder cover 132 with the internal surface of the enlargement 134 so that a circular circumferential welding seam 1 38 results.

Further embodiments of the union of a cylinder cover with the housing are shown in Figures 10 and 11. In the embodiment of Figure 10 the cylinder bore 142 is not offset. Instead, the cylinder cover 140 is formed with a hub 144 extending into the internal space of the cylinder bore 142. In this way, a circumferential offset 146 is formed between the hub 144 and the external portion of the cylinder cover 140 and the cylinder cover 140 rests with its radially projecting rim 148 on the end plane 1 50 which bounds the cylinder bore 142. In this design, the welding seam 1 52 is directed at right angles to the axis of the cylinder, between the end plane 1 50 and the rim 148 of the cylinder cover 140.

In the embodiment shown in Figure 11 the cylinder cover 1 54 is externally formed with a collar 1 56 which engages in a circumferential recess 1 58 of the part comprising the cylinder bore 1 60. The end plane 1 62 of the part surrounding the cylinder bore 160 is formed with an offset and the welding seam 1 62 is directed at right angles to the axis of the cylinder in the range of the end plane 164 of the collar 1 56 and of the reievant portion of the end plane 166.

The embodiment shown in Figure 12 comprises a cylinder cover 1 68 which is entirely inserted in a cylinder bore 170. The welding seam 1 72 is in this case directed parallel with the axis of the cylinder bore between the circumferential surface of the cover 168 and the internal surface of the cylinder bore 1 70. In order to avoid the formation of a crater in the internal zone during electron-beam welding, the welding seam which has to be made from the outside is not with full penetration, its depth being instead less than the depth of the cover 1 68. The cylinder cover 1 68 is formed with a recess 1 74 for reduction of weight.

The cover 1 68 is seated in the cylinder bore 1 70 in a force fit. Therefore, the welded joint may be spot-welded only. A slippage-phase 1 69 is provided at the internal rim of the cover 168 to enable its insertion in the cylinder bore in a force fit.

A third embodiment of a cylinder 218 closed by a cover 216 is shown in Figure 13. In this case, both the end wall 220 and the cover 21 6 are formed with offsets. A welded joint 222 is provided between the external portion of the cover 21 6 with minor diameter and the respective external portion of the end wall 220. As the forces due to the pressure formed in the internal space of the cylinder 218 during braking action are absorbed by the offsetting 224, the welded joint substantially serves as a seal only in this case.

A fourth embodiment is shown in Figure 14. In this version, the front wall 226 of the cylinder 228 is more closed so that the diameter of the cover 230 is smaller. Again, a welding seam 232 is provided between the circumferential surface of the cover 230 and the inner wall of the bore which receives the cover 230. The cover is seated in the bore in a force fit and the depth of the weld is less than the depth of the cover. Thanks to the relatively small diameter of the cover 230, the joint between the cover 230 and the front wall 226 will be subject only to a low amount of strain.

A brake caliper housing 20 is illustrated diagrammatically in Figures 7 and 8. In principle, this brake caliper housing 20 corresponds to the brake caliper housing described above in connection with Figures 1 to 6 and 9 to 11.

Figures 7 and 8 serve particularly to illustrate in more detail the division of the brake caliper housing and the position of the welding seams.

As also described already above, the brake caliper housing 20 comprises first and second radial limbs 28, 36 which are interconnected by a bridge portion 34. In the version illustrated in this instance, the limb 28 which contains the brake cylinder 30 forms a first housing part 188, while the bridge portion 34 and the second radial limb 36 constitute a second housing part 1 90. At its end facing the bridge portion 34 the first housing part 1 88 presents a joint face 192 running at right angles to the axis of the cylinder and the second housing part 1 90 forms a corresponding joint face 194 at the end of the bridge portion 34 facing the brake cylinder 30. The abutting joint faces 192, 194 are bonded by a welding seam 196 carried out be electron-beam or by laser welding.

In another embodiment, a welding seam 198 runs between the end of the bridge portion 34 which faces the limb 36 and that limb 36. This welding seam 1 98 is outlined by a zigzag line in Figures 7 and 8. A fruther alternative consists in a welding seam 200 positioned parallel with the axis of the cylinder as outlined again by a zigzag line in Figure 7.

The housing parts 188, 190 may be made of different materials. In particular, nodular cast iron, cast aluminium, forged aluminium, and die-cast aluminium would appear expedient for the housing part 188, while nodular cast iron, forged steel, cast aluminium, forged aluminium, and diecast aluminium will advantageously be employed for the housing part 1 90. The most varied combinations of these materials will be adequate as the specific cases of application may be.

During manufacture of the brake caliper housing, the housing parts 188, 190 are ready machined before welding, which means that the housing part 1 88 is provided with the cylinder bore 130 and with the grooves 202 and 204 for accommodation of seals and boots. If the cylinder bore 130, 142, 160 is a through bore such as is shown in Figures 7 to 12, the abutment faces for the cylinder cover will also be ready machined already in this process step. The housing part 190, too, undergoes all operations necessary for its ready machining. After the housing parts 188, 1 90 are so finished, they are joined together by electron-beam or laser welding. The welding of the cylinder cover may be carried out before or after the welding of the housing limbs.

Figure 1 5 shows an embodiment of a brake caliper housing 234 in which the radial housing parts 236, 238 and the bridge portion 240 are formed in one piece. In the external radial housing part 238, a through clearance 242 with U-shaped section is provided through which the cylinder bore 244 can be performed.

The clearance 242 accommodates a pressure plate 246 whose outer contour is at least partly adapted to the contour of the clearance. The pressure plate 246 and the radial housing part 238 are welded together by electron-beam or laser welding or by other appropriate welding processes. Manufacturing is particularly simplified by this embodiment. The pressure plate 246 welded in subsequently offers a surface to apply an external brake pad (not shown) and leads to an increased rigidity of the housing.

Claims

1. A brake caliper housing, in particular for a spot-type disc brake of an automotive vehicle, of the kind comprising at least two housing parts which are interconnected, characterised in that the already machined housing parts (188, 190) are welded together.

2. A brake caliper housing as claimed in claim 1, having a first radial housing limb which is furnished with a cylinder bore for accommodation of a piston, a second radial housing limb, and a bridge portion connecting the radial housing limbs, characterised in that the welded joint is located at the point of transition from the bridge portion (34) to the first housing limb (28) which contains the cylinder bore (130).

3. A brake caliper housing as claimed in claim 1, having a first radial housing limb which is furnished with a cylinder bore for accommodation of a piston, a second radial housing limbs, and a bridge portion connecting the radial housing limb, characterised in that the welded joint is located at the point of transition from the bridge porton (34) to the second radial housing limb (36).

4. A brake caliper housing as claimed in claim 2 or 3, characterised in that the housing parts (1 88, 190) to be connected to each other are formed with joint faces (192, 1 94) extending at right angles to the longitudinal axis of the housing.

5. A brake caliper housing as claimed in claim 3, characterised in that the housing parts (188, 190) connected with each other are provided with joint faces running parallel with the longitudinal axis of the housing.

6. A brake caliper housing as claimed in any one of the preceding claims, with an axial cylinder bore provided in a first housing limb being configured as a through bore and covered by a lid, characterised in that the cover lid (132, 140, 144) is welded to the radial housing limb (28).

7. A brake caliper housing as claimed in claim 6, characterised in that the cylinder bore (130) is formed with a radial enlargement (134) at its internal end facing away from the bridge portion (34), in that the cover lid (132) is inserted in the enlargement (134) and in that the welding seam (138) connects the peripheral surface of the cover lid with the inner circumferential surface of the enlargement, the welding seam being directed axially against material of the housing which surrounds the cylinder bore (130).

8. A brake caliper housing as claimed in claim 6, characterised in that the cover lid (14) is seated on the front side of the housing limb (28) and in that the welding seam (152) is located at the circumference of that part of the housing limb (28) which forms the cylinder.

9. A brake caliper housing as claimed in claim 8, characterised in that the cover lid is formed with an axially extending outer collar (136) and in that the housing limb surrounding the cylinder bore (160) has an external annular recess (158) into which engages the collar (156) of the cover lid so that joint faces extending at right angles to the longitudinal axis of the cylinder are formed which are bonded by a welding seam (162).

10. A brake caliper housing as claimed in claim 8, characterised in that the cover lid is formed with an internal hub (144) extending into the internal space of the cylinder bore and being adapted to the latter.

11. A brake caliper housing as claimed in claim 6, characterised in that the cover lid is entirely inserted in the cylinder bore and in that the welding seam is directed parallel with the axis of the cylinder bore between the circumferential surface of the cover lid and the internal surface of the cylinder, with the depth of the said welding seam being less than the depth of the cover lid at its rim.

12. A brake caliper housing as claimed in any one of the preceding claims, characterised in that the housing parts (188, 190) are made of different materials.

1 3. A brake caliper housing according to claim 12, characterised in that the housing limb (28) containing the cylinder is made of nodular cast iron, cast aluminium, die-cast aluminium or forged aluminium.

14. A brake caliper housing according to any one of the preceding claims, characterised in that the housing part containing the bridge portion (34) is made of nodular cast iron, forged steel, cast aluminium, forged aluminium or die-cast aluminium.

1 5. A method of manufacturing a brake caliper housing, in particular for a spot-type floating caliper vehicle brake, with at least two of the said housing limbs forming the housing being manufactured as blanks and being substantially already machined characterised in that the already machined housing limbs are welded together.

1 6. A method according to claim 15, characterised in that the welded joint is made by electron-beam welding.

17. A method according to claim 15, characterised in that the welded joint is made by laser welding.

1 8. A method as claimed in any one of claims 1 5 to 17, with the housing being formed with a first radial housing limb which is furnished with a cylinder bore for accommodation of a piston, then with a second radial housing limb, and with a bridge portion which connects the radial housing limbs, characterised in that the welded joint is located at the point of transition from the bridge portion to the first housing limb which contains the cylinder bore.

1 9. A method as claimed in any one of claims 15 to 17, with the housing being formed with a first radial housing limb which is furnished with a cylinder bore for accommodation of a piston, then with a second radial housing limb, and with a bridge portion which connects the radial housing limbs, characterised in that the welded joint is located at the point of transition from the bridge portion to the second radial housing limb.

20. A method according to claim 18 or 19, characterised in that the housing limbs to be connected to each other are formed with joint faces extending at right angles to the longitudinal axis of the housing.

21. A method as claimed in claim 19, characterised in that the housing limbs to be connected to each other are provided with joint faces running parallel with the longitudinal axis of the housing.

22. A method according to any one of claims 1 5 to 21, with an axial cylinder bore provided in a first radial housing limb being configurated as a through bore and being covered by a lid, characterised in that the cover lid is welded to the radial housing limb.

23. A method according to claim 21, characterised in that the cylinder bore is enlarged at its internal end, in that the cover lid is inserted in the enlargement and in that the weld is made at the internal front side of the housing limb comprising the cylinder.

24. A method according to claim 22, characterised in that the cover lid is seated on the front side of the housing limb comprising the cylinder and in that the weld is made at the circumference of the housing limb comprising the cylinder.

25. A method as claimed in any one of claims 1 5 to 24, characterised in that the housing limbs are made of different materials.

26. A brake caliper housing according to any one of claims 1 to 14, with the cylinder bore being covered by a lid, characterised in that the cover lid (168) is seated in the cylinder bore (170) in a force fit.

27. A brake caliper housing according to claim 26, characterised in that the cover lid (168) is formed with a slippage phase (169) at its internal rim.

28. A brake caliper housing as claimed in any one of claims 6 to 14, 26 or 27, characterised in that the welded joint is spot-welded.

29. A brake caliper housing as claimed in any one of claims 2 to 14 or 25 to 28, characterised in that the external radial housing part (238) has an axial through clearance (242) which accommodates a pressure plate (246) that is welded to the housing part.

30. A brake caliper housing substantially as described with reference to the accompanying drawings

31. A method of manufacturing a brake caliper housing substantially as described with reference to the accompanying drawings.