GB2136921A

GB2136921A - Improvements in disc assemblies for vehicle disc brakes

Info

Publication number: GB2136921A
Application number: GB08406262A
Authority: GB
Inventors: John Adamson
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1983-03-18
Filing date: 1984-03-09
Publication date: 1984-09-26
Also published as: GB8406262D0; GB2136921B

Abstract

A disc assembly for a vehicle disc brake comprises an annular braking ring (3) adapted to be removably mounted directly on a radial disc mounting seat (2) of a driven axle (1). A connection between the braking ring (3) and the axle (1) comprises a plurality of angularly spaced resilient roll pins (7) which are housed in complementary axially extending openings (5, 6) in the mating faces of the seat and the disc to transmit the braking moment from the ring to the axle and also locate the ring with respect to the axle in a radial sense. Nut and bolt connections (12, 13) are operative to clamp spaced clamp plates (14, 15) into engagement with complementary radially spaced clamp faces at opposite ends of the mounting seat and the ring to restrain movement of the ring (3) with respect to the seat (2) in an axial direction. <IMAGE>

Description

SPECIFICATION Improvements in disc assemblies for vehicle disc brakes This invention relates to disc assemblies particularly for railway vehicle disc brakes.

In known disc assemblies of the kind set forth an annular disc is mounted on a steel hub and, typically, the hub may be mounted as a separate unit on an wheel driven axle to be braked, usually with an interference fit provided between the axle and the hub. Usually the disc is in the form of a cast iron or steel ring attached to the hub by a connection which permits the ring to expand and contract relatively freely without inducing excessive stresses in the disc assembly.

In installations in which the wheels are relatively small in diameter, the spatial constraint imposed in a radial sense by the distance between the outside diameter of the hub, and the loading gauge, severely limits the diametral size and thus the thermal capacity of the disc which can be fitted.

Also when more than one disc is to be fitted to a hub mounted on an axle by means of an interference fit, it is usual to step the outside diameter of the hub in such a manner that the discs are located on surfaces of different diameters. This is necessary to facilitate installation and removal of the discs from the axle.

According to our invention at least one annular disc is mounted on a driven axle having an integral radial disc mounting seat, the disc comprising an annular braking ring removably mounted on the seat, and a connection being provided between the braking ring and the axle, the connection comprising a plurality of angularly spaced resilient roll pins which are housed in complementary axially extending openings in the mating faces of the seat and the ring to transmit the braking moment from the ring to the axle and also locate the ring with respect to the axle in a radial sense.

Making the connection directly between the braking ring and the axle simplifies the construction. The elimination of the hub means that the inner diameter of the ring is effectively reduced. Thus, for a disc of a given outside diameter, the effective area of the braking surface is increased and hence the thermal performance of the disc is improved.

Also more than one disc can be mounted on a common mounting seat on the axle with spacers disposed between adjacent faces of adjacent discs.

In such a construction it is not necessary for the seat to be stepped, and the seat is of a constant diameter throughout its axial length.

Preferably each opening is defined by pairs of superimposed axially extending grooves in the said mating faces and each groove is conveniently of semi-circular outline.

Clamp means may also project through each roll pin to restrain movement of the ring with respect to the seat in an axial direction.

Conveniently the clamp means comprises a nut and bolt connection operative to clamp spaced clamp plates into engagement with complementary radially spaced clamp faces at opposite ends of the mounting seat and the ring.

Two embodiments of our invention are illustrated in the accompanying drawings in which: Figure 1 is an end elevation of a disc assembly for a rail vehicle brake with one nut and bolt connection omitted for clarity; Figure 2 is a plan view including a section through the braking ring; Figure 3 is a perspective view of a disc mounting seat on an axle; and Figure 4 is a longitudinal section similar to Figure 2 but showing two discs mounted on a common axle.

The disc assembly illustrated in the drawings comprises a wheel or motor driven axle 1 provided at at least one suitable location with a locai portion of increased diameter which may be of constant nominal outside diameter throughout its axial length and forms a radial disc mounting seat 2. A braking disc comprising an annular ring 3 of a known ventilated type is removably mounted on the axle 1 with the cytindrical face 4 defining its inner diameter mating with the outer face of the -disc mounting seat 2.

Superimposed pairs of complementary angularly spaced grooves 5 and 6 are provided in the mounting faces of the ring 3 and the seat 2 respectively, and the grooves of each pair define a substantially cylindrical opening into which a resilient roll pin 7 is inserted with an interference fit. Each roll pin 7 extends axially through its respective opening. The ends of each roll pin 7 may be substantially flush with the opposed braking faces 8, 9 of th braking ring 3 with which brake pads are engageable, and with shoulders 1 Q, 11 at opposite ends of-the disc mounting seat 2. The roll pins 7 act to transmit the braking moment from the ring 3 to the axle 1, locate the ring 3 with respect to the axle in the radial sense, and compensate for expansion and contraction of the ring 3 with respect to the disc mounting seat 2.

The ring 3 is held against movement with respect to the axle 1 in an axial sense by means of a plurality of headed clamp bolts 12, the shank of each of which projects through a corresponding roll pin 7. The head of each bolt 12 and a corresponding nut 1 3 clamp a pair of clamp plates 14 and 1 5 against the shoulders 10 and 1 and against faced areas 1 6 on the braking faces 8 and 9.

Since the shoulders 10 and 11 are inclined or curved, the clamp plates 1 4 and 1 5 aer suitably shaped. This serves to prevent the plates 1 4 and 1 5 from rotating when the bolts 1 2 are tightened.

More than one ring cn be mounted on the seat 2. As illustrated in Figure 4 two rings 20, 21 are mounted on the seat 2, which is of increased axial length. Each ring 20, 21 is secured to the axle 1 by means of roll pins 7 as described above with reference to Figures 1 to 3. The bolts 12 are increased in length to enable the shanks to extend through both roll pins 7. A spacer 22, in the form of a ring, is clamped between adjacent faces of the two rings 20, 21 to hold them in a spaced relationship, and the spacer 22 is provided with angularly spaced openings 23 through which the bolts 12 also extend with clearance.

This construction of the disc assembly of Figure 4 is otherwise the same as that of Figures 1 to 3, and corresponding reference numerals have been applied to corresponding parts.

Claims

1. In combination: a driven axle, and at least one annular disc, in which the axle has an integral radial disc mounting seat, the disc comprises a hub-less annular braking ring removably mounted on the seat, and a connection is provided between the braking ring and the axle, the connection comprising a plurality of angularly spaced resilient roll pins which are housed in complementary axially extending openings in the mating faces of the seat and the ring to transmit the braking moment from the ring to the axle and also locate the ring with respect to the axle in a radial sense.

2. The combination as claimed in Claim 1, in which each opening is defined by pairs of superimposed axially extending grooves in the said mating faces.

3. The combination as claimed in Claim 2, in which each groove is of semi-circular outline.

4. The combination as claimed in any of Claims 1 to 3, in which clamp means also project through each roll pin to restrain movement of the ring with respect to the seat in an axial direction.

5. The combination as claimed in Claim 4, in which a single disc is mounted on the axle, and the clamp means comprises a nut and bolt connection operative to clamp spaced clamp plates into engagement with complementary radially spaced clamp faces at opposite ends of the mounting seat and the ring.

6. The combination as claimed in Claim 5, in which the shank of each bolt extends through a corresponding roll pin.

7. The combination as claimed in Claim 4, in which at least two discs are mounted on the axle, and the clamp means comprises a nut and bolt connection operative to clamp spaced clamp plates into engagement with complementary radially spaced clamp faces at opposite ends of the mounting seat and at the two outermost ends of the discs, and a spacer is clamped between adjacent faces of the disc.

8. The combination as claimed in Claim 7, in which the seat is of a constant diameter throughout its axial length.

9. The combination as clained in Claim 7, in which the shank of each bolt extends through corresponding aligned roll pins and through a complementary opening in the spacer.

10. The combination as claimed in Claim 5 or Claim 7, in which shoulders of curved or inclusive outline are provided at opposite ends of the seat, and the clamp plates are of complementary shape.

11. The combination of a driven axle and a disc substantially as described herein with reference to and as illustrated in Figures 1 to 3 of the accompanying drawings.

12. The combination of a driven axle and two discs substantially as described herein with reference to as illustrated in Figure 4 of the accompanying drawings.