GB2158170A

GB2158170A - Spot-type disc brakes

Info

Publication number: GB2158170A
Application number: GB08509400A
Authority: GB
Inventors: Claus-Peter Panek; Uwe Bach
Original assignee: Alfred Teves GmbH
Current assignee: Continental Teves AG and Co OHG
Priority date: 1984-04-28
Filing date: 1985-04-12
Publication date: 1985-11-06
Also published as: ES286149U; SE8502002L; SE8502002D0; IT8520407A0; SE455338B; FR2563596B1; GB8509400D0; IT1184748B; DE3415993A1; ES286149Y; DE3415993C2; FR2563596A1; IT8520407A1; GB2158170B

Abstract

The brake has a caliper (4) in aperture (28) of which which are disposed two brake pads (16, 18) provided with backplates (20, 22) and held, by means of pad retaining pins (34, 36), in the brake caliper on opposite sides of the brake disc. A wire pad retaining spring (50) clamps the brake pads against the pad retaining pins; it comprises a central section (56) exciting pressure from top on backplates (20, 22), and two stems (52, 54) extending substantially in parallel to backplates (20, 22). Provision is made for at least one of the stems (52, 54) to be disposed on the side of the corresponding pad backplate (20, 22) facing the brake disc (6). Lug (66) is provided on at least one stem by U-shaped bend or as separate port. Noses (72, 74) are provided holding the backplate (20), with low axial clearance: this prevents reversed assembly of spring (50). Stems are formed as shown in Fig. 3 - arcuate section (64) extends underneath pin (36). <IMAGE>

Description

SPECIFICATION Spot-type disc brakes The present invention is concerned with a spot-type disc brake comprising a brake disc, a brake caliper in which are disposed two brake pads provided with backplates, which brake pads, by means of pad retaining pins, are held in the brake caliper on opposite sides of the brake disc and are clamped by a wire pad retaining spring against the pad retaining pins, with the wire pad retaining spring comprising a central section in abutment with the brake pads, and two stems extending substantially in parallel to the brake pads, and clamped to a brake caliper portion, preferably to the pad retaining pins, and is concerned with wire pad retaining springs for use therein.

Pad retaining springs in spot-type disc brakes of this type are well known in the art.

In the conventional arrangements, the stems of the pad retaining spring extending in parallel to the pad backplates are respectively guided on the side of the backplates facing away from the brake disc. In order to have sufficient space available for the stems, an axial space must be left between the backplate and the part of the brake caliper in which the pad retaining pins are held. This will reduce the length of the guides and bores for the pad retaining pins which will involve the risk of an inadvertent loosening of the pad retaining pins and, hence, of a failure in operation of the entire brake system.

It is, therefore, an object of the invention to provide a disc brake in which no space of assembly will be required between the pad backplate and the part of the brake caliper designed to hold the pad retaining pins.

According to one aspect of the invention there is provided a spot-type disc brake comprising a brake disc, a brake caliper in which are disposed two brake pads provided with backplates, which brake pads, by means of pad retaining pins, are held in the brake caliper on opposite sides of the brake disc and are clamped by a wire pad retaining spring against the pad retaining pins, with the wire pad retaining spring comprising a central section in abutment with the brake pads, and two stems extending substantially in parallel to the brake pads, and clamped to a brake caliper portion, preferably to the pad retaining pins, characterised in that at least one of said stems is disposed on the side of the respective pad backplate facing the brake disc, and that the central section forms an axial lug axially extending along the respective brake pad and the backplate thereof, respectively, and that the respective backplate, in the direction of the brake disc axis, is in abutment with an anchoring portion of the brake caliper.

According to another aspect of the invention there is provided a wire pad retaining spring for use in a spot-type disc brake comprising a brake disc, a brake caliper in which are disposed two brake pads provided with backplates, which brake pads, by means of pad retaining pins, are held in the brake caliper and clamped in use by said wire pad retaining spring against the pad retaining pins, with the wire pad retaining spring comprising a central section in abutment with the brake pads, and two stems extending in use substantially in parallel to the brake pads and clamped in use to a portion of the brake caliper, preferably to the pad retaining pins, characterised in that at least one of the stems is disposed in use on the side of the respective pad backplate facing the brake disc, and that the central section forms an axial lug axially extending in use along the brake pad and the backplate thereof, respectively.

The solution according to the invention, in simple manner, provides for an arrangement wherein due to the elimination of the assembly space for the stems of the pad retaining spring, the bores and guides, respectively, for the pad retaining pins can be of a more extended length thus being held more safely.

It is only then that it will be possible for the present brake system to be used with small assembly spaces. A left-and-right reversed assembly of the pad retaining spring and, hence, an oblique positioning of the pad in the radial direction will be avoided in that the pad by corresponding positioning means is held with no substantial interspace on the anchor of the brake caliper and/or in that a hump or the like is formed on the caliper, preferably on the part forming a brake cylinder, preventing the lug provided on the spring from being disposed in that area.

According to an advantageous embodiment of the invention, the anchoring portion is a radially extending leg of the brake caliper.

Feasibly, in terms of manufacturing considerations, at leat one nose is provided to form the positioning means disposed in a radially extending aperture of the brake caliper. Such a nose or noses can be readily incorporated into the broaching profile of the brake caliper aperture.

The pad retaining spring is, according to one form of embodiment which is particularly easy to manufacture, such that the central section and the corresponding stem of the pad retaining spring, respectively, is of a curved configuration.

Fixation and compression, respectively, of the spring, can be achieved if the stems embrace one of the pad retaining pins and are guided underneath the other pad retaining pin in order to load the spring.

Embodiments of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a plan view of a spot-type disc brake including brake pads and a pad retaining spring, Figure 2 is a plan view of the pad retaining spring as used with the spot-type disc brake shown in Fig. 1, and Figure 3 is a side view of the pad retaining spring shown in Fig. 2.

Referring to the drawings, Fig. 1 shows a plan view of a spot-type disc brake 2 including a brake caliper 4 and a brake disc 6. The brake caliper 4, in the longitudinal section extending in axially parallel relationship, is of a U-shaped configuration and comprises two radially extending legs 8, 10 and a bridging section 12. Disposed in leg 10 is an actuating means 14 not shown in any detail, that may comprise a piston/cylinder unit. Provided on either side of the brake disc 6 is a brake pad 1 6 and 18, respectively. The brake pad 1 6 associated with the actuating means 1 4 during applying of the brakes is forced directly by the actuating means 14 in axial manner against the brake disc 6.Due to the resultant reaction force, the brake caliper 4 is axially displaced in the opposite direction thereby forcing, by means of leg 8, the other brake pad 18 against the brake disc 6. Brake pads 16, 1 8 respectively composed of a backplate 20, 22 and a pad body 24, 26 disposed thereon are provided in a radially extending aperture 28 of the brake caliper 4. With the circumferentially provided front faces thereof they are supported, in the circumferential direction, on the lateral delimitation walls 30, 32 of the aperture 28 to receive the peripheral pressure arising during the braking operation. For the brake pad 1 6 associated with the actuating means it will also be possible to be supported in a brake carrier aperture (not shown).In the axial direction, the interior brake pad 1 6 is supported on the actuating means 14, preferably on the piston of the said actuating means, whereas the outer brake pad 1 8 is supported on the outer leg 8 of the brake caliper 4. To prevent the brake pads 16, 1 8 from dropping out of the aperture 28, two pad retaining pins 34, 36 extending in axially parallel relationship are provided. The pad retaining pins 34, 36 with the ends thereof are disposed in holes provided in legs 8, 10 of the brake caliper 4, with the holes 38, 40 for the pad retaining pin 34 being shown.For fixing the pad retaining pins 34, 36 in the holes, the pad retaining pins at the inner ends thereof are provided with a deformable element 42 deformed when driving in the pad retaining pins so as to safeguard, by frictional resistance, that the pad The pad retaining pins 34, 36 for retaining the brake pads 16, 1 8 are guided through holes provided in the backplates 20, 22 thereof. Two of these holes through which the pad retaining pin 34 is guided, are designated by reference numerals 44, 46.As the brake pads 16, 1 8 relative to the pad retaining pins 34, 36 must be circumferentially movable in order to be capable, during applying of the brakes, to be supported on the delimitation walls 30, 32 of the aperture, and as a certain clearance is also required in the radial direction, a pad retaining spring 50 is provided by way of which the brake pads 16, 1 8 are forced against the pad retaining pins 34, 36.

The pad retaining spring 50 comprises-as is clearly shown by Fig. 2-two stems 52, 54 extending substantially in parallel to the backplates 20, 22 of the brake pads and disposed in axially spaced relationship with respect to one another, which stems 52, 54 are interconnected via a central section 56 here extending substantially in parallel to the pad retaining pins 34, 36. As shown in Fig. 3, stems 52, 54 comprise an upper section 58 and a lower section 60 interconnected through an arcuate section 62. The ends of the bottom sections 60 are connected by the central section 56. Provided on the side of the upper section 58 facing away from the arcuate section 62, on each stem, is another arcuate section 64 which, however, is openended.Formed on at least one side on the corresponding stem, (stem 54 in the drawing), is a lug 66 axially projecting beyond the corresponding stem 54 of the pad retaining spring 50. Lug 66 is formed by a substantially U-shaped bend of the bottom section 60 and the central section 56, respectively although it and the central section 56, respectively although it can also be formed differently, e.g. in the form of a separate part connected to the stem.

The assembly position of the pad retaining spring 50 which, in the present instance, on one side is provided with a lug 66, is shown in Fig. 1. The stem 52 of the pad retaining spring 50 is disposed in the interspace between the wall 68 of the aperture 28 extending in parallel to the brake disc, and the rear of the backplate 20. The arcuate section 64 disposed on the upper section 58 of the stem 54 extends underneath the pad retaining pin 36.

The arcuate section 64 provided on the upper section 58 of the stem 54 extends underneath the pad retaining pin 36. The upper section 58 is then returned across the other pad retaining pin 34 by means of the arcuate section 62 to the bottom side thereof.

In the area between the pad retaining pins 34, 36, the bottom section 60 passes over into the central section 56 extending substantially in parallel to the pad retaining pins 34 and 36. The pad retaining spring 50, by the central section 56, will exert a pressure from the top on the backplates 20, 22. As the stem 54 of the pad retaining spring 50 is disposed on the side of the backplate 22 facing the pad body 26, the pad retaining spring 50, on that side, with lug 66, is supported on the back plate 22. Clamping of the pad retaining pins 34, 36, incidentally, corresponds to that of stem 52.According to the clear cut illustration in Fig. 1, owing to the internal arrangement of the stem 54, no interspace is required between the rear side of the backplate 22 and the wall 70 of the aperture 28 thus enabling the backplate 22 to be directly supported on the said wall 70 so that the space saved thereby in the axial direction will be available for an extension of hole 40 thereby offering an improved fixation for the pad retaining pins 34, 36.

It will be imperative to avoid an incorrect assembly of spring 50. An incorrect assembly could cause an oblique position of the pad in the radial direction because a spring stem could be located between the pad backplate 22 and the aperture wall 70. To avoid this, noses 72, 74 protruding into the interior of the aperture 28 are provided on the delimitation walls 30, 32 of the aperture 28. The said noses 72, 74 simply formed during broaching of the aperture profile during the manufacturing process serve to hold the brake pad 1 8 with a low axial clearance on the wall 70 of the aperture 28 so that there will be no room left for spring stem 52 and 54, respectively in the interspace between the said wall and the rear side of the backplate 22. To prevent a left-and-right reversed assembly of spring 50, a hump or lug 76 or the like will be provided on the caliper in the area of the central section 56 of the pad retaining spring 50.

Hump 76, in the arrangement as shown, is provided approximately midway of the leg 10 containing the actuating piston in the area of the aperture wall 68 so that lug 66 of spring 50 cannot be located in that area thereby readily safeguarding the proper assembly position.

Claims

1. A spot-type disc brake comprising a brake disc, a brake caliper in which are disposed two brake pads provided with backplates, which brake pads, by means of pad retaining pins, are held in the brake caliper on opposite sides of the brake disc and are clamped by a wire pad retaining spring against the pad retaining pins, with the wire pad retaining spring comprising a central section in abutment with the brake pads, and two stems extending substantially in parallel to the brake pads, and clamped to a brake caliper portion, preferably to the pad retaining pins, characterised in that at least one of said stems (54) is disposed on the side of the respective pad backplate (22) facing the brake disc (6), and that the central section (56) forms an axial lug (66) axially extending along the respective brake pad and the backplate thereof, respectively, and that the respective backplate (22), in the direction of the brake disc axis, is in abutment with an achoring portion of the brake caliper (4).

2. A disc brake according to claim 1, characterised in that means (72, 74) are provided that prevent a left-and-right reversed assembly of the pad retaining spring from occurring.

3. A disc brake according to claim 2, characterised in that the means for preventing a left-and-right reversed assembly comprise positioning means (72, 74) holding the respective backplate, in the axial direction, on the anchoring portion with low allowance for movement.

4. A disc brake according to claim 2 or claim 3, characterised in that the means for preventing a left-and-right reversed assembly comprise a hump or the like disposed on the caliper in the area of the central section of the spring on a leg of the caliper forming a brake cylinder.

5. A disc brake according to any one of the preceding claims, characterised in that the anchoring portion is a radially, with respect to the brake disc axis, extending leg (8) of the brake caliper (4).

6. A disc brake according to claim 3, characterised in that the positioning means comprise at least one nose (72, 74) disposed in a radially, with respect to the brake disc axis, extending aperture (28).

7. A wire pad retaining spring for use in a spot-type disc brake comprising a brake disc, a brake caliper in which are disposed two brake pads provided with backplates, which brake pads, by means of pad retaining pins, are held in the brake caliper and clamped in use by said wire pad retaining spring against the pad retaining pins, with the wire pad retaining spring comprising a central section in abutment with the brake pads, and two stems extending in use substantially in parallel to the brake pads and clamped in use to a portion of the brake caliper, preferably to the pad retaining pins, characterised in that at least one of the stems (52, 54) is disposed in use on the side of the respective pad backplate facing the brake disc (6), and that the central section (56) forms an axial lug (66) axially extending in use along the brake pad and the backplate thereof, respectively.

8. A pad retaining spring according to claim 7, characterised in that the central section and the adjacent stem, respectively, is of a curved configuration to form the axial lug (66).

9. A pad retaining spring according to claim 7 or claim 8, characterised in that in use the stems (52, 54) embrace one of the pad retaining springs (34, 36) and are guided underneath the other pad retaining pin for compressing the spring.

10. A wire pad retaining spring for use in a spot-type disc brake and substantially as herein described with reference to Figs. 2 and 3 of the accompanying drawings.

11. A spot-type disc brake including a wire pad retaining spring and substantially as herein described with reference to the accompanying drawings.