GB2060096A

GB2060096A - Wheels Having Brake Discs

Info

Publication number: GB2060096A
Application number: GB8029470A
Authority: GB
Original assignee: KNORR BREMSE GmbH; Knorr Bremse AG
Current assignee: KNORR BREMSE GmbH; Knorr Bremse AG
Priority date: 1979-09-11
Filing date: 1980-09-11
Publication date: 1981-04-29
Also published as: DE2936668B1; DE2936668C2; FR2465123B1; FR2465123A1; GB2060096B

Abstract

A vehicle wheel body incorporates an annular brake disc (6,7) formed by two half rings which are arranged on one side of a web (2) of the wheel, wherein a guide (15) extends parallel to the axis of the wheel body and engages substantially without clearance in aligned bores in each half ring and the web for the fixed mounting of the half ring on the web. The guide being located in a plane passing through the axis of the wheel body and extending perpendicular to the plane of division between the two half rings, and wherein threaded fasteners (12 to 14) associated with each half ring are uniformly distributed on each side of the plane containing the guide (15), the fasteners extending parallel to the axis of the wheel body and with clearance through aligned bores in the half ring and the web in order to provide loose mountings for the half ring on the web. A guide surface (33, 36) is provided on each half ring, and a parallel counter surface on central reinforcement (8) of the web (2) engages with the guide surface to hold and support the half ring on the web. The guide surface and the counter surface engage throughout an arc subtending an angle alpha 2 on each side of the plane containing the guide (15), when the brake disc is in the cold state. When the brake disc heats-up, contact is still maintained between the guide surface and counter surface at contact points (39, 40) so as to provide guidance and support for the half ring during thermal movements in cooperation with the fixed mounting provided by the guide (15). <IMAGE>

Description

SPECIFICATION A Vehicle Wheel Body Incorporating a Brake Disc This invention relates to a vehicle wheel body incorporating a brake disc and is particulariy, though not exclusively, concerned with such a wheel body for use in a rail vehicle.

It is known from German Patent Specification 2,133,235 to provide a rail vehicle wheel body having an annular brake disc formed by two half rings which are arranged on one side of a web of the wheel, each ring being fixedly mounted on the web by means of an axially extending clamping sleeve which engages substantially without clearance in aligned bores in the ring and the web.

The clamping sleeve is arranged in a vertical plane (which is perpendicular to the plane of division between the two half rings), and each half ring is also loosely mounted on the web by means of bolts extending parallel to the axis of the wheel body and which are uniformly distributed on either side of the vertical plane and mounted with clearance within aligned bores. The loosely mounted bolts ailow limited relative thermal movement of each half ring, but in order to avoid pivoting of each half ring about its clamping sleeve, the half rings are joined to each other by means of guide bolts which extend perpendicular to the plane of division between the rings.

Apart from the fact that guide bolts of this type with the associated bores in the half rings require a considerable production cost, corrosion of the guide bolts can be relatively great because of the relatively small surface they offer. In addition the half rings in the region of the bores for the guide bolts must have relatively strong walls, which, however, is not favourable from a thermal point of view.

It is an object of the invention to provide a vehicle wheel body incorporating a brake disc composed of two half rings, having simplified and less expensive guidance for the thermal movements of the half rings and which is more resistant to corrosion than hitherto.

According to the invention there is provided a vehicle wheel body incorporating an annular brake disc formed by two half rings which are arranged on one side of a web of the wheel and comprising: a respective guide extending parallel to the axis of the wheel body and engaging substantially without clearance in aligned bores in each half ring and the web for fixed mounting of the half ring on the web, said guide being located in a plane passing through the axis of the wheel body and extending perpendicular to the plane of division between the two half rings;; and a respective set of threaded fasteners associated with each half ring and uniformly distributed on either side of said plane containing the guide, said fasteners extending parallel to the axis of the wheel body and with clearance through aligned bores in the half ring and the web in order to provide loose mountings for the half ring on the web; in which there is provided a guide surface on each half ring and a parallel counter surface on the web, said surfaces being interengageable to hold and support the half ring on the web, and the axis of the guide being arranged to extend outside the surface normals of the guide surfaces.

One embodiment of vehicle wheel body according to the invention will now be described in detail, by way of example only, with reference to the accompanying drawings in which: Fig. 1 a and 1 b jointly show a quadrant of a wheel hub-brake disc in part section; Fig. 2 is a half section along the lines la-la in Fig. 1 a (right half of Fig. 2) and along the lines Ib--lb in Fig. 1 b (left half of Fig. 2); and Fig. 3 is a schematic representation of a half ring of the brake disc in the cold and in the hot state.

According to Fig. 1 a, 1 b and 2, there is shown a rail vehicle wheel body incorporating brake disc rings 6 and 7 secured to the side faces 4 and 5 of a web 2 of a wheel. The web 2, which is formed on a hub portion (not shown) of a rail vehicle has, in its radially central section, an annular reinforcement 8 whose flat radial side faces form the sections of the side faces 4 and 5, against which the brake disc rings 6 and 7 abut. Each brake disc ring, as can be seen from Fig. 1 b, is divided into two half rings 10 and 11 along a horizontal plane of dividion 9, which half rings are respectively held on a web 2 by a set of threaded fasteners comprising six securing bolts (12 to 14) and a guide bolt 1 5.Of the six securing bolts shown in Fig. 1 a and 1 b, only the three right hand bolts 12, 13 and 14 and the centre guide bolt 1 5 on the right hand half of the half ring 1 0 are shown. The bolts are uniformly distributed over the half ring. They extend respectively parallel to the axis of the wheel hub from brake disc ring 7 through the web 2 to the other brake disc ring 6.

The heads 16 and the nuts 17 of the bolts 12 to 1 5 are arranged to be countersunk with respect to the axially outer ring surfaces 1 8 and 1 9 of the brake disc rings 6 and 7. As can be seen from Fig.

2, left half, the shanks of the bolts 12 to 14 project directly, but with radial clearance 20, through bores in the web 2 and bores 21 aligned with one another in the brake disc ring 6 and 7.

The guide bolt 15 is located in a vertical plane 22 (perpendicular to the plane of division 9), on the other hand and engages substantially without clearance in bores 23 and 24 aligned with one another in the web and the brake disc ring 6 and 7. It is clear from Fig. 2 that the bolts 12 to 14 are provided with nuts corresponding to nut 1 7 and that the guide bolt 15, having a press fit, has a head corresponding to the head 1 6 of the securing bolt 14.

The two half rings of the brake disc ring 6 and 7 are thus respectively held on the web 2 by a guide or tight-fit bolt 1 5 in the vertical plane 22, and by six securing bolts 12 to 14 uniformly distributed over the circumference symmetrically to the plane 22.

The section of the brake disc rings 6 and 7 facing the web 2, as is generally usual, are constructed as finned bodies with radial ribs 30.

For the formation of guide surfaces, the ribs 30 have axially inner projections 31 (forming part of an annular guide) in an angle zone 2 (Fig. 1 a and 3), which projections define a radially inner annular recess 32 which forms substantially axial guide surfaces 33 in the zone of the individual ribs.

For the formation of additional guide surfaces, the ribs 30 have radially outer projections 34 over the entire circumference of a half ring, which projections define a radially outer annular recess 35 for the formation of further substantially axial guide surfaces 36.

The annular reinforcement 8 on the web engages into the radially inner and the radially outer recesses 32 and 35. In the cold state of the brake disc ring, the radially inner and the radially outer guide surfaces 33 and 36 abut the associated axial counter surfaces on the annular reinforcement 8 of the web, substantially without clearance and without force fit.

When the brake disc ring is heated, with its half rings held fixedly merely by a guide- or tight-fit bolt 15 on the web, the brake disc ring in the zone of the clearances of the securing bolts 12-14 is able to expand radially.

In Fig. 3 there is shown the expansion of a half ring during maximum heating. The thick solid lines show radially inner and outer boundary lines of the heated half ring 6 in contrast to the corresponding boundary lines of the cold half ring in thin outline. In the cold state of the half ring in Fig. 3, the radially inner boundary line 37 of the half ring substantially coincides with a radially outer boundary line 38 of the web. In the zone of the tight-fit bolt 15, the half ring 6 heated to maximum is enlarged radially on both sides of the tight-fit bolt 1 5 and with increasing distance circumferentially from the tight-fit bolt 1 5, the heated half ring bends increasingly upwards at both its ends.In this way the radially inner boundary line 37 of the heated half ring 6, with the radially outer boundary line 38 of the cold web 2 forms two points of intersection 39 and 40 which lie symmetrically to the vertical plane 22.

These points of intersection 39 and 40 define an angle a2 with the centre point of the web 2, and provide support and guidance for the relative thermal movements of each half ring, in cooperation with the fixed central mounting provided by guide bolt 15.

By virtue of the guide surfaces on a half ring of the brake disc ring 6 and 7 extending through the arc 41 in the zone of the inner boundary line 37 determined by the angle a2, and the associated counter surfaces of the web 2 extending through the same arc 41 in the zone of the outer boundary line 38 on the web, then with maximum hub temperature the outermost guide surface sections in the zone of points 39 and 40 manage to touch the associated counter surfaces on the web substantially without clearance and without force.

With increasingly lower friction disc temperature, correspondingly increasingly lower friction disc temperature, correspondingly increasingly larger areas of the guide and counter guide surface sections engage in the arc zone of the angle a2 substantially without clearance and without force.

The half rings of the brake disc ring 6 and 7 are thus carried at least at 3 points (tight-fit bolt 1 5 and contact points 39 and 40). When the brake disc ring is cold, the guide surfaces abut the associated counter surfaces on the web substantially over the entire length of the arc of the angle a2.

Figs. 1 a, 1 b and 2 merely show, as stated above, examples for the construction and arrangement of the guide surfaces 33 on the brake disc ring 6 and 7 and the associated counter surfaces on the reinforcement 8 of the hub 2.

The angle a2 and the arc section determined by it between the points 39 and 40 for the arrangement of the outermost guide surfaces on the brake disc rings and the associated counter surfaces on the web is co-determined by the distance of the axis of the tight-fit bolt 1 5 from the centre point of the web or the brake disc ring; and of course the radial distance of the axis of the tight-fit bolt 15 from the centre point of the web or the brake disc ring is greater than the radial distance of the arc 41 between the outermost contact points 39 and 40 and the centre point.

With the correct design of the position of the right-fit bolt 1 5 (with a larger radius) and of the length of the arc 41 through the angle a2 (with a smaller radius), it is guaranteed that the brake disc ring is sufficiently supported on the hub during each heating although each of its half rings is held fixedly on the wheel hub only by means of a guide (1 5) lying in the plane perpendicular to its plane of division.

As will be evident from the drawings, the axis of the guide 15 is located outside the surface normals of at least two guide surfaces provided, one on each side of the guide 1 5, by means of the guide surface 33. Thus, there will be formed a three point support (1 5, 39, 40) for each half ring.

Claims

1. A vehicle wheel body incorporating an annular brake disc formed by two half rings which are arranged on one side of a web of the wheel and comprising: a respective guide extending parallel to the axis of the wheel body and engaging substantially without clearance in aligned bores in each half ring and the web four the fixed mounting of the half ring on the web, said guide being located in a plane passing through the axis of the wheel body and extending perpendicular to the plane 6f division between the two half rings;; and a respective set of threaded fasteners associated with each half ring and uniformly distributed on either side of said plane containing the guide, said fasteners extending parallel to the axis of the wheel body and with clearance through aligned bores in the half ring and the web in order to provide loose mountings for the half ring on the web; In which there is provided a guide surface on each half ring and a parallel counter surface on the web, said surface being interengageable to hold and support the half ring on the web, and the axis of the guide being arranged to extend outside the surface normals of at least two guide surface portions provided by said guide surface.

2. A wheel body according to Claim 1, in which the guide surface extends substantially in the circumferential direction of the brake disc or the hub.

3. A wheel body according to Claim 1 or 2, in which the guide surface on each half ring comprises circumferential surface segments of an annular guide extending symmetrically relative to the plane containing the guide.

4. A wheel body according to any one of Claims 1 to 3, in which the outermost portions of the guide surface lying furthest away from said plane containing the guide are symmetrical relative to the plane to define an angle a2 at the centre of the wheel body and, dependent upon the selection of this angle, the distance of the axis of the guide from the centre of the brake disc is so selected that with maximum friction disc temperature in operation, the outermost guide surface portions engage the associated counter surfaces on the web substantially without clearance and without force-fit and that, with the friction disc at ambient temperature, guide surface regions extending within said angle also engage the associated counter surfaces on the web substantially without clearnace and without force-fit.

5. A wheel body according to Claim 3, in which said annular guide is located radially inwardly of the axis of the guide and is formed by a recess in an axially projecting brake disc ring portion, and in which the associated counter surfaces are formed on the web by an annular reinforcement on a radially central section of the brake disc which engages in said recess, whereby, in the cold state of the brake disc, at least part of said annular guide abuts over its entire length substantially without clearance and without force fit against the counter surfaces of the web.

6. A wheel body according to Claim 5, in which said annular guide is formed by cooling ribs extending substantially radially and uniformly distributed throughout the circumference of the associated half ring.

7. A wheel body according to any one of the preceding claims, in which each half ring of the brake disc has additional guide surfaces located radially tutwardly of the axis of the guide and extending in the circumferential direction, which surfaces in the cold state of the brake disc abut associated counter surfaces of the web substantially without clearance and without force-fit.

8. A wheel body according to Claim 7, in which said additional guide surfaces extend throughout the entire circumference of the half rings.

9. A wheel body according to any one of the preceding claims, in which said guide is a bolt.

10. A wheel body according to Claim 1 and substantially as hereinbefore described with reference to, and as shown in the accompanying drawings.