GB1585159A

GB1585159A - Friction pad assemblies for vehicle disc brakes

Info

Publication number: GB1585159A
Application number: GB4140476A
Authority: GB
Original assignee: Girling Ltd
Current assignee: Girling Ltd
Priority date: 1976-10-06
Filing date: 1976-10-06
Publication date: 1981-02-25
Also published as: JPS5346569A

Description

(54) IMPROVEMENTS IN FRICTION PAD ASSEMBIES FOR VEHICLE DISC BRAKES (71) We, GIRLING LIMITED, a British Company of Kings Road, Tyseley, Birmingham B11 2AH, 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 friction pad assemblies for vehicle disc brakes, each assembly being of the kind comprising opposite sides defining respectively a friction face for engagement with a rotatable disc, and a thrust receiving face for receiving a force from brake applying means, for example an hydraulic piston or other thrust applying member or support, to urge the friction face into engagement with the disc, and the friction pad assembly is provided with location means by means of which the friction pad assembly can be retained in an operative position in a brake housing.

In a known friction pad assembly the location means may comprise an inner edge or steps in side edges of the friction pad assembly for engagement with a complementary shoulder or shoulders in a brake housing and the opposite outer edge of the friction assembly is suitably constructed and arranged to present a plane face which can receive a bias force from resilient means for retaining the inner edge or steps in engagement with the shoulder or shoulders, the resilient means comprising a spring plate of which the edges are received in spaced grooves in the housing and include projections received in notches in the grooves to prevent the plate from moving axially with respect to the housing.

In another known construction the location means may comprise outwardly facing recesses iri the side edges of the friction pad assembly adjacent to its outer edge and which receive resilient tongues On a plate by means of which the pad assembly can be suspended in an Operative position in a brake housing with the plate also including further spring flanges for engagement with parts Of the housing to locate it against movement with respect to the housing in an axial direction.

According to our invention a disc brake assembly comprising a rotatable disc and a caliper straddling the peripheral edge of the disc and including a radial opening through which friction pad assemblies can be installed in the brake on opposite sides of the disc, each friction pad assembly having opposite sides defining respectively a friction face for engagement with the disc and a thrust receiving face receiving a force from brake applying means and having two laterally spaced radial lugs projecting from its outer edge of which the lateral dimension between the inner faces of the lugs at their inner ends is greater than the lateral dimension between the inner faces of the lugs at their outer ends to define a pair of spaced recesses, the caliper being provided on opposite sides of the radial opening with limbs in which are provided pairs of recesses corresponding to the recesses in the pad assemblies, and side edges of a blade spring extending over the peripheral edge of the disc being received in the recesses in the pad assemblies and the limbs, the side edges when the blade spring is unstressed being spaced apart by a distance greater than the spacing between the recesses of pairs so that the blade spring is stressed when in its position of use.

Assembly of the brake can be accomplished simply by engaging one edge of the spring in corresponding recesses in the pad assemblies and deforming the spring into registry at its opposite edge in the other recesses.

Preferably all the recesses are symmetrically arranged and are located in an axially superimposed relationship with the side edges of the blade spring being parallel and substantially continuous.

In one construction the blade spring comprises an axially extending planar central body leading into diverging edge portions of which the angle of divergence corresponds substantially with the angle of convergence of the edges of the lugs and the edge portions are deformed back on themselves in to free edge flanges which lie in a common plane and together with the edge portipns are received in the recesses.

Conveniently at least one tag is deformed from one of the flanges and away from the adjacent edge portions to engage against a part of the brake to locate the spring axially with respect to the brake.

One embodiment of our invention is illustrated in the accompanying drawings in which: - Figure I is a side elevation of an hydraulically operated disc brake for a vehicle including a half section in the plane of the disc; Figure 2 is a side view of a friction pad assembly incorporated in the brake of Figure 1; and Figure 3 is a perspective view of a blade spring for locating the friction pad assemblies in the disc brake.

The disc brake illustrated in the drawings comprises a rigid caliper 1 of generally U shaped outline which is secured to a fixed part adjacent to one face of a rotatable disc (not shown) and which includes spaced limbs 2 and 3.

The limbs 2 and 3 are located on opposite sides of the disc and include a radial opening 4 through which friction pad assemblies 5 can be inserted into, and removed from, the brake in a radial direction.

Each friction pad assembly 5 comprises a pad 6 of friction material carried by a rigid backing plate 7, the outer face of the pad 6 remote from the backing plate 7 comprises a friction face for engagement with the disc, and the outer face of the backing plate 7 remote from the pad comprises a thrust receiving face for receiving a brake applying force from a piston working in an hydraulic cylinder 8 in an adjacent limb 2, 3 of the caliper. The backing plate 7 is formed with parallel ends 9 which engage slidably with drag-taking abutment faces 10 at opposite ends of the opening 4, and with radially innermost and outermost edges 11 and 12. Laterally spaced lugs 14 project radially outwards from the outermost edges 12 and the inner faces 15 of the lugs converge outwardly to define pairs of spaced recesses 16 which are superimposed axially upon complementary recesses 17 in the limbs 2 and 3 of the caliper.

The friction pad assemblies 5 are retained in the caliper 1 in suspended operative positions between the abutment surfaces 10 by means of a detachable blade spring 18 of elongate outline comprising a planar central body 19 leading into diverging edge portions 20, which are inclined at substantially the same angle as the inner faces of the lugs 15, and the edge portions 20 at their parallel outer edges are deformed back on themselves into face edge flanges 21 defining feet which lie in a common plane and are received in the recesses 16 and 17.

In an unstressed condition the free outer edge portions 20 of the blade spring 18 are spaced apart by a greater distance than the spacing between the recesses 16, 17 of each pair so that when installed in the brake the blade spring is in a stressed condition. To assemble the brake the friction pad assemblies are inserted radially through the outer end of the opening 14 and one edge of the blade spring 18 where it joins the adjacent flange 21 is inserted into the corresponding recesses bf the four pairs. The spring 18 is then compressed circumferentially so that the opposite edge can be received within the other recesses by moving that edge radially inwards, and then releasing the spring 18.

A pair of axially spaced tags, of which only one is illustrated at 22, are located in the flanges for engagement with parts of the caliper 1 to locate the spring 18 against movement with respect to the caliper 1 in an axial direction. The tags 22 are spaced inwardly from the ends of the spring 18 for engagement with the inner ends of the limbs 2.

In a modification the tags 22 may be located at the extreme ends of the spring 18 for engagement with the outer faces of the limbs at the extreme opposite ends of the caliper 1.

In the construction described above both tags 22 may be located in the same flange or, alternatively, may be located in different flanges.

WHAT WE CLAIM IS: - 1. A disc brake assembly comprising a rotatable disc and a caliper straddling the peripheral edge of the disc and including a radial opening through which friction pad assemblies can be installed in the brake on opposite sides of the disc, each friction pad assembly having opposite sides defining respectively a friction face for engagement with the disc and a thrust receiving face for receiving a force from brake applying means and having two laterally spaced radial lugs projecting from its outer edge of which the lateral dimension between the inner faces of the lugs at their inner ends is greater than the lateral dimension between the inner faces of the lugs at their outer ends to define a pair of spaced recesses, the caliper being provided on op opposite sides of the radial opening with limbs in which are provided pairs of recesses corresponding to the recesses in the pad assemblies, and side edges of a blade spring extending over the peripheral edge of the disc being received in the recesses in the pad assemblies and the limbs, the side edges

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. to free edge flanges which lie in a common plane and together with the edge portipns are received in the recesses. Conveniently at least one tag is deformed from one of the flanges and away from the adjacent edge portions to engage against a part of the brake to locate the spring axially with respect to the brake. One embodiment of our invention is illustrated in the accompanying drawings in which: - Figure I is a side elevation of an hydraulically operated disc brake for a vehicle including a half section in the plane of the disc; Figure 2 is a side view of a friction pad assembly incorporated in the brake of Figure 1; and Figure 3 is a perspective view of a blade spring for locating the friction pad assemblies in the disc brake. The disc brake illustrated in the drawings comprises a rigid caliper 1 of generally U shaped outline which is secured to a fixed part adjacent to one face of a rotatable disc (not shown) and which includes spaced limbs 2 and 3. The limbs 2 and 3 are located on opposite sides of the disc and include a radial opening 4 through which friction pad assemblies 5 can be inserted into, and removed from, the brake in a radial direction. Each friction pad assembly 5 comprises a pad 6 of friction material carried by a rigid backing plate 7, the outer face of the pad 6 remote from the backing plate 7 comprises a friction face for engagement with the disc, and the outer face of the backing plate 7 remote from the pad comprises a thrust receiving face for receiving a brake applying force from a piston working in an hydraulic cylinder 8 in an adjacent limb 2, 3 of the caliper. The backing plate 7 is formed with parallel ends 9 which engage slidably with drag-taking abutment faces 10 at opposite ends of the opening 4, and with radially innermost and outermost edges 11 and 12. Laterally spaced lugs 14 project radially outwards from the outermost edges 12 and the inner faces 15 of the lugs converge outwardly to define pairs of spaced recesses 16 which are superimposed axially upon complementary recesses 17 in the limbs 2 and 3 of the caliper. The friction pad assemblies 5 are retained in the caliper 1 in suspended operative positions between the abutment surfaces 10 by means of a detachable blade spring 18 of elongate outline comprising a planar central body 19 leading into diverging edge portions 20, which are inclined at substantially the same angle as the inner faces of the lugs 15, and the edge portions 20 at their parallel outer edges are deformed back on themselves into face edge flanges 21 defining feet which lie in a common plane and are received in the recesses 16 and 17. In an unstressed condition the free outer edge portions 20 of the blade spring 18 are spaced apart by a greater distance than the spacing between the recesses 16, 17 of each pair so that when installed in the brake the blade spring is in a stressed condition. To assemble the brake the friction pad assemblies are inserted radially through the outer end of the opening 14 and one edge of the blade spring 18 where it joins the adjacent flange 21 is inserted into the corresponding recesses bf the four pairs. The spring 18 is then compressed circumferentially so that the opposite edge can be received within the other recesses by moving that edge radially inwards, and then releasing the spring 18. A pair of axially spaced tags, of which only one is illustrated at 22, are located in the flanges for engagement with parts of the caliper 1 to locate the spring 18 against movement with respect to the caliper 1 in an axial direction. The tags 22 are spaced inwardly from the ends of the spring 18 for engagement with the inner ends of the limbs 2. In a modification the tags 22 may be located at the extreme ends of the spring 18 for engagement with the outer faces of the limbs at the extreme opposite ends of the caliper 1. In the construction described above both tags 22 may be located in the same flange or, alternatively, may be located in different flanges. WHAT WE CLAIM IS: -

1. A disc brake assembly comprising a rotatable disc and a caliper straddling the peripheral edge of the disc and including a radial opening through which friction pad assemblies can be installed in the brake on opposite sides of the disc, each friction pad assembly having opposite sides defining respectively a friction face for engagement with the disc and a thrust receiving face for receiving a force from brake applying means and having two laterally spaced radial lugs projecting from its outer edge of which the lateral dimension between the inner faces of the lugs at their inner ends is greater than the lateral dimension between the inner faces of the lugs at their outer ends to define a pair of spaced recesses, the caliper being provided on op opposite sides of the radial opening with limbs in which are provided pairs of recesses corresponding to the recesses in the pad assemblies, and side edges of a blade spring extending over the peripheral edge of the disc being received in the recesses in the pad assemblies and the limbs, the side edges

when the blade spring is unstressed being spaced apart by a distance greater than the spacing between the recesses of pairs so that the blade spring is stressed when in its position of use.

2. A disc brake assembly according to Claim 1, in which all the recesses are symetrically arranged and are located in an axially superimposed relationship with the side edges of the blade spring being parallel and substantially continuous.

3. A disc brake assembly according to Claim 1 or Claim 2, in which the blade spring comprises an axially extending planar central body leading into diverging edge portions of which the angle of divergence corresponds substantially with the angle of convergence of the edges of the lugs and the edge portions are deformed back on themselves into free edge flanges which lie in a common plane and together with the edge portions are received in the recesses.

4. A disc brake assembly according to Claim 3, in which at least one tag is deformed from one of the flanges and away from the adjacent edge portions to engage against a part of the brake to locate the spring axially with respect to the brake.

5. A friction pad assembly for a disc brake substantially as herein described with reference to and as illustrated in Figure 2 of the accompanying drawings.

6. A disc brake substantially as herein described with reference to and as illustrated in the accompnying drawings.