GB1600657A

GB1600657A - Disc brake

Info

Publication number: GB1600657A
Application number: GB4927/78A
Authority: GB
Original assignee: Wabco Fahrzeugbremsen GmbH
Current assignee: Wabco Fahrzeugbremsen GmbH
Priority date: 1977-02-14
Filing date: 1978-02-07
Publication date: 1981-10-21
Also published as: NL182745C; DE2706115A1; ATA49378A; NL182745B; FR2380470A1; SE437553B; SE7800224L; CH626691A5; DE2706115C2; IT1203167B; FR2380470B1; IT7867291A0; PL204596A1; JPS6116853B2; AT382445B; BR7805088A; JPS53100373A; SU698549A3; HU176179B; YU34078A

Abstract

The disc brake has brake anchor plates for accepting the braking torque, which brake anchor plates are connected to brake-lining carriers (24). Provided on the outer periphery of a pull-action application device (26, 28) are partially annular noses (30), behind which there engage cut-outs (31) of brake-lining carriers (24). The noses (30) are axially displaceable and, during their axial displacement, they release the brake-lining carriers (24). The replacement of the brake linings (25) is thus simpler, even when the disc surface is used to the full. <IMAGE>

Description

(54) DISC BRAKE (71) We, WABCO FAHRZEUGBREM- SEN GMBH formerly, WABCO WESTING- HOUSE GmbH, a German Company of 3 Hannover 91, Postfach 91 1280, Federal Republic of Germany, do hereby declare the invention for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to disc brakes and in particular to a so-called "fullcircle" disc brake wherein axially-movable but nonrotatable brake pad carriers encompass the wheel axle.

A full circle disc brake with a circumferential brake housing has been described in German Patent Application No. 2 526 403 and requires that the pads be withdrawn outwards for changing. This disc brake has the disadvantage, that it contains a relatively large number of movable parts to hold and free the pads and that, because of the clearance required between the pad segments for their insertion, only part of the surface is provided with pads. It is considered desirable to provide a full circle disc brake with a construction that permits changing of the pads in a simple manner.

According to this invention there is provided a full circle disc brake including a pair of full circle segmented brake pad carriers axially movable relative to each other, to operate the brake, by an actuating device disposed between the carriers; and means for retaining the pad carriers within the brake; the retaining means being releasable by axial movement thereof to permit the carrier segments to be removed from the disc brake radially thereof.

For simplicity in manufacture and a reduction in the number of movable parts the retaining means are preferably fixed to the actuating device and releasable by a predetermined axial movement of the latter.

Advantageously the retaining means comprise mutually interengaging parts on the carriers and the actuating device. These can be simple to manufacture, can be fixed in position and can provide a simple and effective way to reduce the number of movable parts and to provide a trouble-free method of retaining the brake pad carriers in their position as fitted.

In one preferred form, the interengaging parts comprise dowels which fit into holes in the brake pad carriers. Advantageously the holes have the form of arcuate slots to keep the actuating device free of the braking moment and so as not to transmit stresses due to temperature expansion in the brake pads to the dowels and thus to the actuating device.

In another preferred form the retaining means comprise tangentially directed cutouts and complementarily shaped lugs arranged on the mutually facing sides of neighbouring brake pad carrier segments such that they may fit into each other. This form of retaining means may be suitable not only to locate the brake pad carriers radially but also to take up the twisting moment caused when the brakes are applied.

By way of example, several forms of disc brake embodying the invention will now be described with reference to the accompanying drawings of which: Figs. la and 1b are respectively axial and radial cross-sections through a first disc brake embodying this invention; Figs. 2a and 2b are respectively axial and radial cross-section through a second disc brake embodying this invention; Figs. 3a and 3b are respectively radial and axial cross-sections through a third disc brake embodying this invention; Figs. 4a and 4b are respectively axial and radial cross-sections through a fourth disc brake embodying this invention; Figs. 5a and Sc are respectively radial and axial cross-sections through a fifth disc brake embodying this invention; Figs. 5b and Sd are respectively radial and axial cross-sections through a sixth disc brake embodying this invention; Fig. 6 is an axial cross-section through a seventh disc brake embodying this invention; and Fig. 7 is an axial cross-section through an eigth disc brake embodying this invention.

The version shown in Fig. 1 (a and b) of the disc brake according to the invention has a brake housing 2 connected to a hub 4 of the vehicle wheel 6. The brake housing 2 consists of two ribbed discs 8 and 10 releasably interconnected, e.g. by bolts 14 extending through sleeves or like connecting parts 12. On the axle housing 16 there is a ring 18 with U-shaped channels 20 into which fit right-angle shaped protruberences 22 from the brake pad carrier segments 24, these last being fitted with brake pad segments 25. An annular cylinder 26 encompasses the axle and an annular piston 28 is slidably mounted in the annular cylinder 26 to form the brake actuating device. Cheeks 30 of arcuate shape project axially from the outer surfaces of the annular cylinder and piston, and these cheeks extend into cutouts 31 in the brake pad carriers to interengage therewith and hold the brake pad carriers 24 against movement in the radial direction.

The friction on seals 32 and 34 is so arranged that the ring piston 28 cannot move in the ring cylinder 26 without the influence of external forces.

To change the brake pad carriers 24 with their brake pads 25, the piston 28 and the cylinder 26 are compressed right up against one of the housing discs whereby the cheek 30 frees the brake pad carrier 24 on the opposite side, from the piston or cylinder.

By removing the connecting parts 12, 14 the brake pads can be withdrawn on their carriers and changed. When the brake pad carriers have been changed a single actuation of the brake is sufficient to effect a reengagement of the cheeks 30 with the cutouts 31 on the brake pad carrier 24 and to make the brake ready for use again. It is unnecessary to undo any other parts.

Fig. 2 (a and b) shows another version of a disc brake according to the present invention. The disc brake shown here is of corresponding design to that shown in Fig. 1 with the exception that the cheeks 30 of the actuating device in Fig. 1 are replaced by pins or dowels 40 and that slotted or ovallike holes 42 are provided in the brake pad carrier 24 into which the pins can be passed.

For simplicity, the other parts of the brake which correspond to the further parts in Fig.

1 have been given the same reference numerals as in Fig. 1 and the description of Fig. 1 applies also to them.

The braking moment caused by applying the brake generates a tilting moment on the brake pads and thus on the brake pad carriers; this tries to rotate the brake pad carriers circumferentially about the right-angle protruberences 22. This tilting moment is taken in the version shown in Fig. 1, by the cheek 30 and the brake pad carriers. The cheeks 30 as has been explained, also prevent the brake pads falling out radially.

In the version shown in Fig. 2, the pins 40 take over the tasks of radial retention and absorbing the tilting moment. By the use of slots 42 instead of round holes the danger of jamming is avoided and the thrust is firmly taken up. The contacting faces of the brake pad carrier segments in practice remain stress free.

Another variant of the full circle disc brake according to the invention is illustrated in Fig. 3. In this version, the cheeks 30 of Fig. 1 and the pins 40 of Fig. 2 have been replaced by a closed ring 44 which protrudes and fits into a circumferential groove 46 in the brake pad carrier segments 24. The brake pad carrier segments, the brake pad segments, the annular cylinder and the annular piston have once again been given the reference numerals 24, 25, 26 and 28. In the version shown in Fig. 3 the protruding ring 44 has taken over the task of preventing the brake pad carriers falling out as well as of taking up the tilting moment.

The ring may be replaced by several ring segments and the circumferential groove by several cutouts complementary to the ring segments.

In the versions shown in Figs. 1 to 3, the fact that the protruberences 30 (Fig. 1), 40 (Fig. 2) and 44 (Fig. 3) take up the tilting moment generated when the brake is applied means that forces act on the piston and cylinder 28, 26 which can produce increased operating friction.

Fig. 4 (a and b) shows a version of a brake disc according to the invention, in which the above-mentioned danger of increased friction is reduced because the brake pad carriers are provided with interengaging teeth 48 and 50 on the opposite contact faces.

Thus tipping or tilting of the brake pad carriers which would produce a relative movement at the contact faces, is avoided. The tilting moment is taken up by the brake pad carriers amongst themselves so that no forces act on the remaining parts as a result of the tilting. The direction and/or inclination of the tooth flanks is so chosen that it corresponds to the insertion direction of the brake pad carriers so that an easy changeover capability is ensured.

Since the version shown in Fig. 4 is otherwise similar to the disc brake of Fig. 1 in conception, similar parts have been given the same reference numbers and a further description is similar to the description for Fig. 1.

In Fig. 5 (a, c and b, d) two further versions of the disc brake according to the invention are shown, in which the parts which correspond to those of the disc brake in Figs. 1 to 4 have been given the same reference numbers. Both disc brakes shown in Fig. 5 differ in principle from the disc brakes of Figs. 1 to 4 in that each of the brake pad carriers 24 fitted with brake pads 25 has one or more shallow rectangular cutouts 52 and one or more rectangular lugs 54, the lug(s) of one brake pad carrier fitting into the cutout(s) of the neighbouring carrier.

The brake disc shown in Figs. Sb and Sd also has protruding ribs 56 (as in the brake disc of Fig. 3) running around the actuating device and locating in circumferential grooves 58 formed in the brake pad carriers.

These grooves and ribs do not appear on the version shown in Figs. Sa and 5c.

The shallow cutouts 52 and the lugs 54 allow each brake pad carrier to abut its neighbouring carrier as in the version shown in Fig. 4. Because the direction of the side flanks of the cutouts 52 and the lugs 54 runs at an angle to the insertion direction this provides security without any further precautions against the carriers falling out while the brakes are not applied. In the version shown in Figs. Sb and Sd the means for ensuring that nothing falls out while the brakes are not applied are the ribs and grooves. The interengaging parts, that is the shallow cutouts 52 and the lugs 54 in the brake pad carriers are so designed that on compression of the actuating device, the brake pads as seen in Figs. Sa and Sb can be freed complete in the order, left upper carrier segment, lower carrier segment, right upper carrier segment.

o avoid the danger of an uneven transmission of braking forces to the brake carriers, segments may be milled out in the reg- lon ot the rectangular cutouts and lugs as shown by the broken lines.

Two further versions of disc brakes according to the invention are shown in Figs. 6 and 7.

With the disc brake shown in Fig. 6, a cover is used which consists of two parts 60 and 62, which are held apart by a spring 64 and whose outer edges fit into annular recesses 66 in the brake pad carriers 68. The space where the spring is located is preferably protected by a sleeve 70. The brake pad carriers can be freed for changing, by pressing together the two cover parts.

With the disc brake shown in Fig. 7, the actuating device comprises an annular cylinder 80 with a circumferential rectangular protruberence 82 which fits into a complementarily shaped groove 84 in a brake pad carrier 86. On the opposite side, a tube-shaped part 88 is fitted into a correspondingly shaped groove 89 in a brake pad carrier 90 and held by means of a suitable fixing arrrangement 92, for example a locking ring, which can be fixed in the annular piston 94. A pad change-over can be simply effected by loosening the means of fixing and by pushing part 88 axially sideways which frees one brake pad carrier 90 and at the same time allows the brake pad carrier 86 to be freed by pressing in the annular cylinder 80 - in the drawing this would be to the right. Both the protruberence 82 as well as the part of the tube-shaped part 88 which fits into the groove 89 need not be made as completely closed circles and it is considered possible to use separate ring segments or lugs distributed around the perimeter which fit into complementarily shaped cutouts in the brake pad carriers.

WHAT WE CLAIM IS: 1. A full circle disc brake including a pair of full circle segmented brake pad carriers axially movable relative to each other, to operate the brake, by an actuating device disposed between the carriers; and means for retaining the pad carriers within the brake; the retaining means being releasable by axial movement thereof to permit the carrier segments to be removed from the disc brake radially thereof.

2. A full circle disc brake as claimed in Claim 1, wherein the retaining means are fixed to the actuating device and releasable by a predetermined axial movement of the latter.

3. A full circle disc brake as claimed in Claim 1, wherein the retaining means are releasable by axial movement relative to the actuating device.

4. A full circle disc brake as claimed in any one of the preceding Claims, wherein the said retaining means are arranged to accommodate the radial forces arising in the disc brake assembly during braking.

5. A full circle disc brake as claimed in Claim 1, wherein the retaining means comprise mutually interengaging parts on the carriers and the actuating device.

6. A full circle disc brake as claimed in Claim 5, wherein the interengaging parts comprise protuberences and receptacles therefor.

7. A full circle disc brake as claimed in Claim 6, wherein the protuberences are formed on the actuating device and project into generally complementarily-shaped apertures or recesses formed in the brake pad carriers.

8. A full circle disc brake as claimed in Claim 7, wherein the protuberences are axially protruding lugs, and the apertures or recesses are correspondingly shaped cutouts on the brake pad carriers.

9. A full circle disc brake as claimed in Claim 8 wherein the lugs are arranged adjacent the outer diameter of the brake pad carriers.

10. A full circle disc brake as claimed in Claim 7 wherein the protuberences are protruding dowels, and the apertures or recesses are holes in the brake pad carriers.

11. A full circle disc brake as claimed in Claim 10, wherein the holes are circumfe

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. brake pad carriers 24 fitted with brake pads 25 has one or more shallow rectangular cutouts 52 and one or more rectangular lugs 54, the lug(s) of one brake pad carrier fitting into the cutout(s) of the neighbouring carrier. The brake disc shown in Figs. Sb and Sd also has protruding ribs 56 (as in the brake disc of Fig. 3) running around the actuating device and locating in circumferential grooves 58 formed in the brake pad carriers. These grooves and ribs do not appear on the version shown in Figs. Sa and 5c. The shallow cutouts 52 and the lugs 54 allow each brake pad carrier to abut its neighbouring carrier as in the version shown in Fig. 4. Because the direction of the side flanks of the cutouts 52 and the lugs 54 runs at an angle to the insertion direction this provides security without any further precautions against the carriers falling out while the brakes are not applied. In the version shown in Figs. Sb and Sd the means for ensuring that nothing falls out while the brakes are not applied are the ribs and grooves. The interengaging parts, that is the shallow cutouts 52 and the lugs 54 in the brake pad carriers are so designed that on compression of the actuating device, the brake pads as seen in Figs. Sa and Sb can be freed complete in the order, left upper carrier segment, lower carrier segment, right upper carrier segment. o avoid the danger of an uneven transmission of braking forces to the brake carriers, segments may be milled out in the reg- lon ot the rectangular cutouts and lugs as shown by the broken lines. Two further versions of disc brakes according to the invention are shown in Figs. 6 and 7. With the disc brake shown in Fig. 6, a cover is used which consists of two parts 60 and 62, which are held apart by a spring 64 and whose outer edges fit into annular recesses 66 in the brake pad carriers 68. The space where the spring is located is preferably protected by a sleeve 70. The brake pad carriers can be freed for changing, by pressing together the two cover parts. With the disc brake shown in Fig. 7, the actuating device comprises an annular cylinder 80 with a circumferential rectangular protruberence 82 which fits into a complementarily shaped groove 84 in a brake pad carrier 86. On the opposite side, a tube-shaped part 88 is fitted into a correspondingly shaped groove 89 in a brake pad carrier 90 and held by means of a suitable fixing arrrangement 92, for example a locking ring, which can be fixed in the annular piston 94. A pad change-over can be simply effected by loosening the means of fixing and by pushing part 88 axially sideways which frees one brake pad carrier 90 and at the same time allows the brake pad carrier 86 to be freed by pressing in the annular cylinder 80 - in the drawing this would be to the right. Both the protruberence 82 as well as the part of the tube-shaped part 88 which fits into the groove 89 need not be made as completely closed circles and it is considered possible to use separate ring segments or lugs distributed around the perimeter which fit into complementarily shaped cutouts in the brake pad carriers. WHAT WE CLAIM IS:

1. A full circle disc brake including a pair of full circle segmented brake pad carriers axially movable relative to each other, to operate the brake, by an actuating device disposed between the carriers; and means for retaining the pad carriers within the brake; the retaining means being releasable by axial movement thereof to permit the carrier segments to be removed from the disc brake radially thereof.

rentially extending slots.

12. A full circle disc brake as claimed in Claim 7, wherein the protuberences are constituted by an axially protruding ring which fits into complementarily shaped grooves in the brake pad carriers, the grooves constituting the said apertures or recesses.

13. A full circle disc brake as claimed in Claim 7, wherein the protuberences are constituted by axially projecting ring segments which fit into complementarily shaped cutouts in the brake pad carriers, the said cutouts constituting the said apertures or recesses.

14. A full circle disc brake as claimed in Claim 12 or 13, in which the ring and grooves or the ring segments and cutouts are arranged adjacent the outer diameter of the disc brake.

15. A full circle disc brake as claimed in Claim 1 wherein the returning means comprise tangentially directed cutouts and complementarily shaped lugs arranged on the mutually facing sides of neighbouring brake pad carrier segments such that they may fit into each other.

16. A full circle disc brake as claimed in Claim 3, wherein the retaining means comprise tangentially directed teeth arranged on the mutually facing sides of neighbouring brake pad carrier segments for mutual intermeshing engagement.

17. A full circle disc brake as claimed in Claim 16, wherein the tooth flanks lie alternately in the radial pull-off direction of the respective neighbouring brake pad carrier segment.

18. A full circle disc brake as claimed in Claim 1, wherein the retaining means comprises a cylindrical cover for the actuating device, which cover releasably engages the pad carriers.

19. A full circle disc brake as claimed in Claim 18, wherein the cover comprises two cylindrical parts which are pre-loaded against each other and retain the brake pad carriers and which can be moved axially against the pre-load to release the brake pad carriers.

20. A full circle disc brake as claimed in Claim 18 or Claim 19, wherein the cover fits into complementarily shaped grooves on the brake pad carriers.

21. A full circle disc brake substantially as herein described with reference to, and as illustrated in, Figs. la and 1b or Figs. 2a and 2b or Figs 3a and 3b or Figs. 4a and 4b or Figs. 5a and Sc or Figs. 5b and 5d or Fig. 6 or Fig. 7 of the accompanying drawings.