GB2146398A - Disc brake assembly - Google Patents

Abstract

A disc brake assembly comprises a stationary support (1) and a movable frame or caliper (6) rigidly connected to a brake actuating means (9,10) positioned on one side of the braking disc and acting directly on one friction pad (4), while on the other friction pad (5) the brake actuating means acts through the frame or the caliper. The movable frame or the caliper are urged to the surface of the support (1) by a spring and has secured thereon substantially perpendicularly to the plane of rotation of the braking disc at least two pins (15, 16) capable of angular swinging movement relative to the point of attachment and self-adjustable on at least two open bearing surfaces (17) provided on the support (1). <IMAGE>

Description

SPECIFICATION Disk brake assembly This invention relates to disc brakes of motor vehicles and, more particularly, to disc brakes with a single brake actuating means acting on two friction pads.

The invention is applicable to hydraulically operated brakes of motor vehicles.

The present invention consists in a disc brake assembly wherein a stationary support with two surfaces takes up directly braking forces of friction pads disposed, respectively on two sides of the brake disc, a section of the brake disc being embraced by a movable part of the disc brake assembly having the form of a frame or a caliper and rigidly connected to a brake actuating means positioned on one side of the braking disc and acting directly on one friction pad, while acting on the other friction pad through the frame or caliper, the frame or caliper of the movable part being urged against the surface of the support by a spring, for orientation of the movable part relative to the support said movable part has secured thereon substantially perpendicularly to the plane of rotation of the disc at least two pins capable of angular swinging movement relative to the point of attachment and self-adjustable on at least two 2 open bearing surfaces provided on the support so that they overlie the surfaces that take up the braking forces.

The above arrangement makes it possible for the movable part of the disc brake assembly to contact the bearing surfaces of the support along lines parallel with the travel of the movable part, the open areas about the lines of contact being capable of self-cleaning, which facilitates the travel of the movable part when subjected to dust and road debris.

Preferably, the open surfaces of the support are inclined to planes passing through the axes of the pins.

This allows a continuous contact between the bearing surfaces of the support and the pins orientating the movable part and prevents undesirable clearances during deformation and the caliper and during natural wear of its elements. In addition, such an arrangement poses much lower requirements as to the accuracy of the manufacture of the elements of the disc brake assembly.

The open bearing surfaces of the support may be flat or, alternatively, curvilinear with a curvature radius in excess of the radius of the pin. This provides conditions preventing the packing of road dirt and facilitates self-cleaning of the surfaces.

Also, this enables simplification of the production of disc brake elements.

Preferably, the contacting surfaces of the pins and open surfaces of the support are arranged such that with freshly mounted friction pads friction contact would be more extended than after some wear of the friction pads. This avoids shearing of surface contamination of the pins against the support and prevents increased resistance to the travel of the movable part of the disc brake assembly.

The invention will now be described in greater detail with reference to various specific embodiments thereof taken in conjunction with the accompanying drawings, in which Figure 1 is an end view of a disc brake assembly according to the invention with a movable part in the form of a frame; Figure 2 is a side view of the disc brake assembly according to the invention having the movable part in the form of a frame; Figure 3 is a top view of the disc brake assembly with the movable part in the form of a frame.

Figure 4 shows one alternative embodiment of bearing surfaces of the support; Figure 5 shows the manner in which a pin is secured in a cylinder housing of the disc brake assembly; Figure 6 shows a modified form of securing the pin on the housing through a resilient element; Figure 7 is an end view of the disc brake assembly according to the present invention with the movable part in the form of a caliper; and Figure 8 is a side view of the disc brake assembly with the movable part having the form of a caliper.

The disc brake assembly comprises a stationary support 1 (Fig. 1) with two surfaces 2 and 3 (Fig. 2) adapted to directly take up braking forces from friction pads 4 and 5 (Fig. 3). The movable part of the disk brake assembly has the form of a frame 6 (Fig. 1) enclosing a section of a brake disc 7. The friction pads 4 and 5 are disposed, respectively on two sides of the brake disc as seen best in Fig. 3.

Brake actuating means is fixedly secured on the frame 6 and is formed as a cylinder housing 8 accommodating pistons 9 and 10 having sealing rings 11 and 12 and dust protectors 13 and 14. The brake actuating means is positioned on one side of the brake disc to exert force directly on the friction pad 4 directly and on the friction pad 5 through the frame 6.

The frame 6 is mounted on the support 1 (Fig. 1) by means of guiding pins 15, 16 (Fig. 2) slidable along inclined planar bearing surfaces 17 of the support 1. Bearing surfaces 17a of the support may be curvilinear, the radius of curvature in the contact area being in excess of the radius of the pins (Fig. 4). The guiding pins 15, 16 are secured by one end thereof in the cylinder housing 8 (Fig. 3) to be capable of self-adjustment for ensuring contact lengthwise of the bearing surfaces 17 (Fig. 2) of the support 1. For this purpose the pins 15, 16 are capable of angular swinging movement which is ensured by the provision of a clearance between the socket attachment of the pins 15, 16 in the housing 8 of the brake actuating means and the location of the pins (Fig. 5).This clearance therefore provides for angular turning of the axes of the pins, while during deformations of the elements of the brake mechanism the pins can tightly fit against the bearing surfaces of the support which changed their position under the action of deformation, whereby line contact of the bearing surfaces is en sured. For the same purpose the pins 15, 16 may be connected to the brake actuating means through a resilient element, such as a rubber sleeve (Fig. 6).

A lock spring 18 (Fig. 1) secured in bores of the pins 15, 16 (Fig. 3) acts to prevent these pins 15, 16 from axial displacement relative to the housing 8 (Fig. 3). On the side of the brake disc 7 opposite the brake actuating means the frame 6 bears on a projection 19 provided on the outer surface of the bearing plate of the outer friction pad 5 (Fig. 3). In turn, the friction pad 5 is adapted to bear by its projections 20 (Fig. 2) on the free ends of the pins 15, 16 (Fig. 3). For assuring continuous contact of the pins 15, 16 with the surfaces of the support 1 a spring 21 (Fig. 2) is provided bearing on the support on the two sides of the disc.

Ends of the pins 15 and 16 on which the outer friction pad 5 (Fig. 3) bears are loose and the pins tend to fit snugly along the entire contact line against the bearing surfaces 17 of the support 1 (Fig. 1) under the action of the spring 21.

The guiding pins 15 and 16 also serve for preventing the friction pads 4 and 5 (Fig. 3) from falling out.

With reference to Figs. 7 and 8, there is shown a modified disc brake assembly in the form of a caliper.

The caliper 22 (Fig. 7) embraces a section of the disc.

Attached rigidly to the caliper 22 is brake actuating 7 means 23 in the form of a housing with cylinders and pistons arranged similar to that described with reference to Fig. 3.

The caliper 22 contacts with inclined bearing surfaces 26 of a support 27 under the action of the spring 24 (Fig. 7) through guide pins 25 (Fig. 8).

The pins 25 and their attachment on the brake actuating means are constructed similarly to what has been described with reference to the embodiment of the disc brake assembly with the movable portion in the form of a frame.

A pin 29 is used for attachment of the friction pads 28 shown in Fig. 8. The friction pads 28 have lugs 30 on which guide pins 25 may bear.

The movable part also has portions 31 intended to prevent the pins 25 from moving toward each other.

The position of the free ends of the pins 25 is determined by mutual positioning of the bearing surfaces 26 of the support 27, confining surfaces 31 of the movable part of the disc brake assembly and surfaces of the lug of the outer firction pad.

Under the action of the spring 24 the movable part forces the pins 25 to the bearing surfaces of the support through the outer 8 friction pad, whereby the pins secured in the brake actuating means for angular swinging self-adjustment providing line contact with the surfaces of the support ensuring easy displacement of the movable portion of the disc brake assembly even when dust and road debris level is high.

The disc brake embodying the present invention operates as follows.

When the working fluid transmits pressure to the interior of the housing 8 (Fig. 3) the pistons 9 and 10 act to press the inner friction pad 4 against the working surface of the disc 7. Concurrently, the pressure of the working fluid acts on the bottom of the cylinders inside the housing 1 to displace the movable part together with the frame 6 on the guide pins 6 (Fig. 2) and along the bearing surfaces 17 in a direction opposite to the movement of the pistons 9 and 10 (Fig. 3). Therewith, the outer friction pad is caused to be pressed against the disc.

When pressure of the working fluid is relieved, the pistons 9 and 10 return to their initial position releasing the friction pad 4 under the action of the forces of resilient deformation of the sealing rings 11 and 12 (Fig. 3). Simultaneously, pressure force is relieved from the outer friction pad 5 whereby this pad is drawn away from the disc surface due to disc wobbling. 9 The alternative modification of the disc brake assembly where the movable part has the form of a caliper operates in a similar manner.

The use in a disc brake assembly employing the movable part in the form of a frame element or a caliper of pins secured on the stationary element and capable of angular swinging relative to the point of attachment as well as self-adjustable on two open surfaces on the support makes it possible to minimize the contact area of sliding surfaces and prevent clearances between the cooperating supports. This reduces resistance to the frame movement, minimizes wear between friction pairs and helps improve fuel efficiency.

Claims (6)

1. A disc brake assembly wherein a stationary support with two surfaces takes up directly braking forces of friction pads disposed, respectively, on two sides of the brake disc, a section of the brake disc being embraced by a movable part of the disc brake assembly having the form of a frame or a caliper and rigidly connected to a brake actuating means positioned on one side of the braking disc and acting directly On one friction pad, while acting on the other friction pad through the frame or caliper, the frame or caliper of the movable part being urged against the surface of the support by a spring, for orientation of the movable part relative to the support said movable part has secured thereon substantially perpendicularly to the plane of rotation of the disc at least two pins capable of angular swinging movement relative to the point of attachment and self-adjustable on at least two open bearing surfaces provided on the support so that they overlie the surfaces that take up the braking forces.

2. A disc brake assembly as claimed in claim 1 wherein the open bearing surfaces are inclined to a plane passing through the axes of the pins.

3. A disc brake assembly as claimed in claim 1 or 2 wherein the open bearing surfaces of the support are flat.

4. A disc brake assembly as claimed in claim 1 or 2 wherein the open bearing surfaces of the support are curvilinear in cross-section, the curvature radius of these bearing surfaces exceeding the radius ofthe pins.

5. A disc brake assembly as claimed in claim 1 wherein the pins come into contact with the open bearing surfaces of the support in such a manner that during wear of the friction pads the line of contact is continuously reduced.

6. A disc brake assembly substantially as described in the description with reference to the accompanying drawings.