GB2088499A

GB2088499A - Slidable mounting of disc brake caliper

Info

Publication number: GB2088499A
Application number: GB8133354A
Authority: GB
Original assignee: Rockwell International Corp
Current assignee: Boeing North American Inc
Priority date: 1980-12-01
Filing date: 1981-11-05
Publication date: 1982-06-09
Also published as: GB2140515A; DE3146790A1; FR2495250A1; SE8107094L; AU7691881A; HU188718B; JPS57120739A; BR8107791A; MX155185A; CH658301A5; GB8415594D0; IT8149778A0; IT1142993B; GB2088499B; AU550581B2; CA1171003A

Abstract

A caliper slide pin 19 is carried in an axially extending bore 21 in a boss 24 of a torque plate 30 and is secured by means of a draw key 60 received in a second bore 58 normal to but laterally displaced from axis of bore 21. The draw key is held in the position of Figure 3 by a lock nut 69 but is movable to a position (see Figure 4) to permit withdrawal or insertion of slide pin 19. The pin 19 is undercut at 17 and the key 60 is recessed at 64 but only one of these elements need be recessed. The pin 19 is one of two such pins slidably received in respective pairs of axially spaced bosses 14, 15 of caliper 12. <IMAGE>

Description

SPECIFICATION Disc brake caliper support The present invention relates to a dise brake assembly and more specifically, to improved means for slidably mounting a caliper in a disc brake assembly.

The present invention is particularly applicable to a disc brake assembly which includes a rotor or disc mounted for rotation with a vehicle wheel and a floating caliper straddling the periphery of the rotor.

The caliper is usually mounted on a support plate by means permitting movement of the caliper in an axial direction relative to the torque plate and rotor.

Brake pads are carried by the caliper on opposite sides of the rotor and are movable into contact with oppositely disposed friction brake surfaces of the rotor by means of a suitable actuating mechanism which is usually driving by a fluid motor. In a floating caliper disc brake, each friction pad is located intermediate one depending leg or wall of the caliper and the adjacent friction surface of the rotor. The actuating mechanism is usually carried by a depending wall or leg of the caliper and serves to move the adjacent friction pad axially into contact with the rotor, the reaction force of the contact serving to draw the other leg of the caliper and the other friction pad into contact with the opposite surface of the rotor.

Disc brake assemblies have been provided with calipers mounted for sliding movement on axially oriented rods and pin-like elements carried by a support or torque plate rigidly secured to a vehicle axle. Examples of such prior art arrangements may be found in U.S. Patent Nos. 3,388,774,3,893,546 and 4,093,043.

Although various possibilities exist for slidably mounting a caliper to a torque plate, many of these are beset with problems involving means for satisfactorily securing the slide pins or rods to the torque plate while permitting access to the brake assembly for maintenance purposes as for example, withdrawing and replacing the friction pads. The present invention provides a simple, economical means for securing a caliper slide pin to a torque plate which prevents accidental displacement of the slide pin while providing for ease of assembly and disassembly.

The present invention provides improved means for slidably mounting a caliper to a support in a disc brake comprising a bore extending axially through the support, a second bore intersecting the first bore, a slide pin carried in the first bore with its ends projecting therefrom, the caliper having a pair of axially spaced bosses with each boss including a bore slidably receiving one of the projecting ends of the slide pin and a draw key in the second bore. The draw key is movable in the second bore to a first position wherein the draw key clears said first bore to permit axial movement of the slide pin in the first bore and to a second position partly within said first bore thereby preventing axial movement of the slide pin relative to the first bore. Means for locking the draw key in the second position is also provided.

In the preferred embodiment, the slide pin is undercut by a groove extending circumferentially around the slide pin and the draw key is recessed intermediate its ends and threaded at one end projecting outward of the second bore. The recess of the draw key is drawn into abutment with the undercut grooved portion of the slide pin when said draw key is moved to the aforesaid second position and a nut threaded to the projecting end of said draw key is tightened against the support to lock the recessed portion of the draw key in the second position with the draw key recess abutting the undercut portion of said slide pin. The advantages offered by the present invention will become apparent from the following description of the embodiment shown in the accompanying drawings.

In the drawings wherein like reference numerals refer to like parts: Figure lisa side view elevation view of a disc brake incorporating the present invention; Figure 2 is a partial front view of the disc brake of Figure 1; Figure 3 is a sectional view taken along lines 3-3 of Figure 2; Figure 4 is a sectional view similarto Figure 3; Figure 5 is of a draw key utilized in the present invention; and Figure 6 is a perspective view of a slide pin utilized in the present invention.

With reference to the drawings, Figures 1 and 2 show a disc brake assembly generally designated by the numeral 10. The assembly 10 includes a sliding or "floating" floating caliper 12 mounted by means of circumferentially spaced, axially aligned pairs of each 14 and 15, and 16 and 17 on slide pins 19 and 20. The slide pins 19 and 20 are respectively mounted in axially extending bores 21,22 respectively provided to bosses 24, 25 at the radially outer extremities of circumferentially spaced radially extending arms 26 and 28 of the brake supporting torque plate or spider 30. The torque plate 30 is provided with a circular array of apertures 31 which receive a plurality of bolts not shown which, in turn, secure the support or torque plate 30 to a flange welded to a vehicle axle 32. The torque plate 30 will of course be welded directly to the axle 32.A rotor 34 having axially spaced, oppositely disposed friction braking surfaces 35 and 36 is secured for rotation with a wheel hub (not shown) carried by the vehicle axle 32 adjacent to the brake assembly 10.

The caliper 12 is a cast metal component comprised of a leg40 extending radially inward adjacent the friction 5urface 36 of rotor 34, an oppositely disposed leg or wall 41 adjacent to friction surface 35 of rotor 34 and a bridge 42 straddling the periphery of rotor 34 and joining the leg 40 to the wall 41. The wall 41 is formed with a generally cylindrical housing 44 having a bore 45 slidably mounting a piston 43 formed integrally with a load applying plate 47.

The contourofthe load applying plate 47 is similar to the contour of the backing plate of friction pad 52 and moves the pad 52 axially into contact with the rotor surface 35 in response to actuation of the brake assembly. The piston 45 and load plate 47 may be moved by suitable hydraulic or mechanical actuating means, not shown. The bridge 42 of caliper 12 is provided with an aperture 46 partially bounded by circumferentially spaced axially extending, radially converging edges 50 and 51 which support a pair of friction pads 52 and 54. The friction pads, 52, 54 are supported in operative position between the oppositely disposed friction surfaces 35,36 of the rotor 34 and the depending leg 40 and wall 41 of caliper 12 by means of radially extending tabs 55, 56 integrally formed as extensions of the backing plates of friction pads 52,54.The circumferentially spaced edges of the friction pad tabs 55,56 slidably engage the edges 50, 51 of caliper aperature 46 and thereby support the friction pads 52, 54.

The caliper 12 and friction pads 52, 54 are in turn slidably supported by slide pins 19 and 20 projecting from the bores 21,22 of the torque plate bosses 24, 25.

As best shown in Figure 2, the slide pin 19 is supported within the cylindrical bore 21 extending axially through the boss 24 provided atthe radially outer extremity of the torque plate arm 26. The caliper 12 is provided with a pair of axially spaced bosses 14, 15, each of which includes a cylindrical bore slidably receiving one end of the slide pin 19 projecting from the bore 21 of torque plate boss 24.

The slide pin 19 is stepped to a smaller diameter portion 17 forming the bottom of a groove disposed circumferentially around the slide pin 19. The diameter of the ends of the slide pin 19 is about 25.2 millimeters and the portion 17 is undercut to a diameter of about 24 millimeters.

The slide pin 19 is secured within the torque plate boss 24 by means of a draw key 60 positioned within a second bore 58 provided to the torque plate boss 24.

As best shown in Figure 1,the axis of the second bore 58 provided to torque plate boss 24 and the axis of the second bore 59 provided to torque plate boss 25 are respectively normal to but laterally displaced from the axes of the slide pin bores 21,22 of torque plate bosses 24 and 25. The second bore 58 as shown by the section view of Figure 3 is laterally offset from the slide pin bore 21 and intersects only a marginal portion or sector of the slide pin bore 21.

This arrangement permits the draw keys 60, 61 to be respectively moved in their respective bores, 58,59 to a first position where the draw keys clear or do not occupy any portion of their respective intersecting slide pin bores 21,22 thereby permitting axial movement of the slide pins 19,20 in the bores 21,22, respectively to a second position where the draw keys 60,61 are located partly within their respective intersecting slide pin bores 21,22, thereby preventing axial movement of the slide pins 19,20 within their bores 21,22. The second bores 58,59 are open at both ends through the torque plate bosses 24,25 to prevent moisture or dirt from accumulating in the bores 21,22.

The draw key 60 as shown by Figure 5, is an elon gate pin or rod having a shank 62 and an externally threaded head 63 of slightly larger diameter than the shank 62. The shank is recessed or undercut at 64 and a groove 67 is provided to the head 63. The recess 64 is provided laterally through the shank 62 for alignment with the slide pin bore 21 and the groove 67 extends dramatically across the top or projecting end surface of head 63 and parallel the base of the recess 64 to visibly indicate the orientation of the recess 64 within the second bore 58.

The draw keys 60,61 are axially removable against the force of a biasing spring 68 seated against a shoulder formed by an undercut at the open end of the bores 58,59. Springs 68 bias against the under surface of a washer 66. A nut 69 is threaded to the head 63 of draw key 60.

The draw key 60 may be axially moved within the bore 58. As shown in Figure 4, with the lock nut 69 moved to a position adjacent the end of the threaded head 63, the draw key 60 may be axially moved inward against the force of biasing spring 68 to a first position where the recess 64 is aligned with the slide pin bore 21 thereby clearing the bore 21 and permitting axial movement of the slide pin 19 within the bore 21 oftorque plate bar 24 as well as the bores provided to the axially spaced bosses 14, 15 of the caliper 12. With the draw key 60 in this position the slide pin 19 may thus be inserted or withdrawn from the caliper and torque plate assembly.

Once the slide pin 19 is inserted within the slide pin bore 21 of torque plate boss 24 and the axially aligned bores provided to the spaced bosses 14,15 of the arms 26,28 of caliper 12, the draw key 60 is drawn axially outwardly to a second position where, as shown by Figure 3, the tapered portion of the recess 64 engages the undercut smaller diameter portion 17 of the slide pin 19 thereby disposing a portion of the draw key 63 within the slide pin bore 21 and abutting the undercut surface 17 of the slide pin 19 and preventing axial movement of the slide pin relative to the slide pin bore 21 of torque plate boss 24. The nut 69 is then threaded down into abutting engagement with the exterior surface of the torque plate boss 24to lock the draw key in position preventing axial movement of the slide pin 19 within the bore 21.

Slide pin 20 and draw key 61, respectively, are identical to the slide pin 19 and draw key 60. The slide pin 20 is secured within the cylindrical bore provided to boss 25 by means of the draw key 61 disposed within the second bore 59 provided to boss 25. The second bore 59 intersects the cylindrical slide pin bore provided to boss 25 and enables the draw key 61 to either clear the bore for removal and/or insertion of the slide pin 20 orto abut against the slide pin 20 and thereby prevent axial movement of the slide pin within bore provided to caliper boss 25 in the same manner as previously described for the draw key 60 and slide pin 19.

Although the slide pins 19 and 20 and the draw keys 60,61 are respectively undercut at 17 and recessed at 64, in the preferred embodiment described above, the invention would function in the same manner if only one element were recessed. For example, if only the slide pin were recessed, then the draw key could be provided of a length to extend into the slide pin recess and capable of being with drawn from that recess and the slide pin bore when it is desired to withdraw or insert the slide pin. If only the draw key were recessed, then the draw key could be designed to enable the recess to abut the cylindrical surface of the slide pin in one position and to clear the slide pin bore when it is desired two withdraw or replace the slide pin.

The invention thus provided a sirnpleconomical means for securing a slide pin to a disc brake sup- port or torque plate which readily perniits removal and replacement of the slide pin.

The invention may also beembodied in other specific forms without departirçfrom the spirit or the essential characleristicsthereof. The foregoing description is therefore to be considered as illustra- tive and nonrestrictive, the scope of the invention being defined by the appended claims and all changes which come within the meaning and range of equivalency of the claims are therefore irnended to be embraced thereby.

Claims

1. In a disc brake fora vehicle including a support and a caliper slidsblytraversirg said support during operation of saW brake, meansforstidably mounting said caliper compr--ising a first bore extending axially through said support, a second bore intersecting said first bore, a slide pin carried in said first bore with its ends projecting therefrom, said caliper having a pair of axially spaced bosses with each boss including a bore slidably receiving one of sa-id projecting ends of said pin and a draw key in said second bore, said draw key being movable in said second bore to a first position wherein said draw key clears said first bore to permit axial movement of said slide pin in said first bore and to a second position partly within said first bore thereby preventing axial movement of said slide pin relative to said first bore, and means for locking said draw key in said second position.

2. The disc brake defined by Claim 1 wherein said draw key is movable into abutment with said slide pin in said second position.

3. The disc brake defined by Claim 1 wherein said draw key is recessed and is movable to align said recess with said first bore in said first position.

4. The disc brake defined by Claim 1 wherein said draw key is recessed intermediate its ends and one of said ends is threaded and projects outward of said second bore and a nut threaded to said draw key and abutting said supportto lock said draw key in said second position with said recess drawn into abutmentwith said slide pin.

5. The disc brake defined by Claim 1 wherein said slide pin is recessed and said draw key is movable into said recess in said second position.

6. The disc brake defined by Claim 1 wherein said draw key is biased to said second position.

7. A disc brake comprising a fixed support member having a pair of circumferentially spaced arms, a caliper and means slidably mounting said caliper on said support member for transverse movement relative to said support, said mounting means including a bore extending axially through each of said arms, a second bore in each respective arm intersecting said axially extending bore in that arm, a pair of pins, each said pin being undercut intermediate its ends and carried on one of said axially extending bores with said undercut aligned with said second bore and with its ends projecting out of said axially extending bore and a pair of draw keys, each said draw key positioned in one of said second bores and having a recess intermediate its ends of a depth adequate to clear the diameter of one of said pins and movable to a first position wherein said draw key recess is aligned with said first bore to permit insertion and removal of said pin in said bore and to a second position wherein said draw key is positioned in said pin recess to locate said pin relative to said second bore and to retain said pin against axial movement in said first bore and means locking said draw key in said second position.

8. The disc brake defined by Claim 7 including means biasing said draw key to said second position.

9. The disc brake defined by Claim 7 wherein said undercut in each respective pin is a groove extending circumferentially around said pin.

10. Disc brake defined by Claim 9 wherein each said groove is located atthe midpoint of each respective pin.

11. In a brake, a rotor having a pair of axially spaced, friction surfaces, a pair of friction elements, one of said elements being disposed adjacent each of said friction faces, a support member mounted adjacent one of said friction faces, said support member having a pair of circumferentially spaced arms defining a recess therebetween, a caliper straddling said rotor and including elements engaging each of said friction elements for urging the latter into braking engagement with each said adjacent friction face when a brake application is effected, at least one of the friction elements being secured to said straddling member, means slidably mounting said straddling member on said support member for transverse movement relative to said rotor, said slidably mounting means including a bore extending axially through each of said arms, a second bore in each respective arm intersecting said axially extending bore in that arm, a pair of pins, each said pin carried in one of said axially extending bores with its ends projecting therefrom, said caliper having circumferentially spaced bores slidably receiving said projecting ends of said pins, and a draw key positioned in each of said second bores, each said draw key abutting one of said pins to retain said pin against axial movement in said first bore, and having a recess and being movable in said second bore to a position where said recess permits axial movement of said pin in said first bore and means for locking said draw key abutting said pin.

12. An element for insertion within one bore to secure a second element at least partly disposed within said one bore comprising an elongate body having a shank and a head, a recess provided laterally through a portion of said shank and means on said head aligned with said recess to indicate the orientation of said recess within said one bore.

13. Theelementdefined by Claim 12 wherein said means for said head is a groove extending diametrically across the projecting end surface of said head parallel to the base of said recess.

14. A disc brake substantially as hereinbefore described with reference to and as shown in the accompanying drawings.