HK1099799B - Brake disk, especially for a rail vehicle - Google Patents

Description

Brake disc, in particular for a rail vehicle

Technical Field

The invention relates to a brake disc, in particular for rail vehicles.

Background

Such brake discs, which are used as so-called axle or wheel brake discs, are subjected to great mechanical and thermal loads during operation, and they require special constructional measures in order to ensure the necessary reliability on the one hand and to carry out assembly or disassembly halfway for better energy conversion on the other hand.

Since the friction ring expands due to the heat generated during braking, it is simply centered on the hub of the axle brake disk, for example, by means of a cylindrical counter bearing, which is not sufficient, in particular, in the case of a two-part high-power brake disk. It is therefore known to fix a slider, in the form of a slider, on the hub. They are guided in radial grooves of the respective friction ring, so that despite the radial expansion of the friction ring, the centering is maintained by the lateral securing of the slide blocks in the radial grooves. This also relates to wheel brake disks, in which case the friction ring is centered on the wheel disk on both sides by means of sliding blocks and is fixed against rotation.

The sliding blocks thus prevent the corresponding friction ring from moving radially as a result of the occurring braking torque or as a result of a dynamic impact, as a result of which an inadmissible imbalance can occur.

Furthermore, friction rings made of ductile materials, such as steel, shrink during operational use due to the plasticizing process in the friction surfaces caused by high braking power and high temperatures. In this case, the friction ring can no longer be removed smoothly from the hub for replacement.

In order to prevent this from happening, the slide block is also used, so that, as already mentioned, the friction ring can expand or contract in a centered manner, for which purpose the cylindrical gap between the friction disk and the hub is correspondingly designed to be comparatively large.

The use of such sliding blocks in wheel brake disks is known, for example, from EP 0683331B 1, EP 0589408B 1, EP 0644349B 1, DE 19727333C 2 and DE 10047980C 2.

The solution disclosed and described there to the stated problem by means of a slide is basically possible. Of course, these ideas can only be realized with comparatively high processing expenditure, which is contrary to an optimized cost-effective production.

In addition, only a relatively small number of sliders, usually three to six, are used, which are correspondingly dimensioned to absorb the necessary loads and therefore require a large spatial space. Also, with known slider layouts and designs, uneven load transfer and the resulting stresses unfortunately result.

The typical width dimension of the slider (about 15-60mm) leads to an increase in the clearance of the sliding guide, i.e. the radial groove, due to the temperature differences occurring during operation of the brake disk. This temperature difference between the radial groove and the slide can be more than 100 ℃ in the friction ring. For example, assume that the slot width bN is 20mm and the temperature difference Δ T is 200K. Then it follows:

Δb＝b·α_th·ΔT20·10^-5·200K＝0.04mm。

this value appears small, but when the friction ring mass is about 100kg (medium size), it has meant an unbalance of U-m-e-4 gm (e-eccentricity). This value is already greater than half the unbalance allowed for high-speed brake discs.

As already mentioned, the radial grooves and the slider are expensive to produce, in particular by the necessary machining operations.

Disclosure of Invention

The object of the invention is therefore to develop brake disks of this type further, which improve their operational reliability and which can be produced more economically.

To this end, the invention provides a brake disk comprising at least one friction ring provided with a radial groove, the friction ring being fastened to a hub or a disk that can be fastened to a shaft by means of clamping screws, wherein, in order to prevent rotation and to center the friction ring, a sliding element connected to the hub or the disk is inserted into the radial groove, characterized in that: each slide is designed as a guide pin made of a semi-finished or standard part, which extends with its rod axis parallel to the clamping screw, and each slide is arranged in an insertion hole of the hub or wheel disc.

The invention firstly allows for the first time the replacement of a small number of micro slide guides with a larger number of so-called micro slide guides, by means of which, for example, the disadvantages described in relation to the prior art relating to the different expansion of the slide and the radial slot and the consequences thereof are overcome. In this connection, the invention provides an excellent improvement in the operational reliability, in particular because no significant imbalance is formed here.

The use of the invention also makes the manufacture of the brake disc simpler and therefore more economical. Furthermore, if the sliding parts are produced, for example, from semi-finished or standard parts, they can be produced, i.e., machined, at low cost. The same applies to the machining of radial grooves in the friction ring, which can also be produced at low cost.

An advantageous further development of the invention provides for: each clamping screw, by means of which the friction ring is fixed to the hub, is assigned a radial groove and an inserted guide pin, wherein the respective radial groove extends from the through-hole for the passage of the through-screw, outwardly or inwardly in the direction of the center line. In any case, the machining of the radial grooves in this region is particularly simple.

A better centering effect is achieved by the guide pins forming the slide, in particular with a small dimensional design in terms of cross-sectional dimensions, and the clearance between the guide pins and the radial grooves associated therewith during heating is reduced.

The gap which has already been mentioned in connection with the prior art and which is caused by temperature differences is, for example, 0.04mm when the groove width is 20mm, whereas this gap is reduced to 0.01-0.02mm when guide pins are used and the radial groove width is 5-10mm, so that the centering quality is improved more than two times.

The guide pins are inserted appropriately into the bores of the wheel hub in the case of axle brake disks or into the bores of the wheel disks, which likewise remain small, so that, despite the large number, the weakening of the material is small and the strength of the component is increased. This is particularly important for brake discs where the mounting holes are machined directly into the web of the wheel.

The cooperation of the sliding elements, which are formed by the possible greater number of positive connections, with the radial grooves allows a more uniform transmission of the braking torque from the friction ring to the hub or the wheel disk. A friction ring with a larger number of connections can also transmit a larger braking torque, in which case the number of guide pins depends on the portion of the braking torque that is to be transmitted by a form-fitting connection.

The arrangement of the guide pins can be chosen according to the number of friction ring connection flanges or screw connection means, but a symmetrical distribution, i.e. 3, 6, 9, 12 guide pins distributed over the circumference, is preferred.

If the sliding element, i.e. the bearing region of the guide pin, is designed flat on the side wall of the radial groove, a form-locking connection which can withstand high dynamic loads is produced between the sliding element and the radial groove. This makes it possible to dispense with the contact-fitting seat of the friction ring on the hub, with the result that even when the friction ring contracts, it can still be removed without problems.

The high degree of redundancy resulting from the large number of positive-locking connections ensures overall a higher reliability of the positive-locking connections, which is of particular advantage in the case of assembly which may have defects.

The small spatial position required for the placement of the sliding elements on the one hand and the radial slots on the other hand allow the use of such a positive connection in disks of almost all types of construction.

Drawings

Embodiments of the invention are explained below with the aid of the figures.

Wherein:

FIG. 1 is a partial longitudinal section through a brake disk according to the invention;

FIG. 2 is a sectional view of the brake disk according to FIG. 1, taken along the line II-II in FIG. 1;

FIG. 3 is a partial longitudinal cross-sectional view of another embodiment of a brake rotor;

FIG. 4 is a cross-sectional view of the brake rotor shown in FIG. 3, taken along line IV-IV of FIG. 3;

FIGS. 5 and 6 show further examples of the invention in section II-II or IV-IV, respectively;

figure 7 is a perspective view of various embodiments of a brake disc detail.

Detailed Description

Fig. 1 to 6 show a brake disk for an axle brake disk, which in its basic configuration comprises a hub 1 and a friction ring 7, respectively, the hub 1 comprising an axially extending hub body 3 and a surrounding hub flange 2 extending radially with respect to the hub body, the friction ring 7 being fastened to the hub 1 by means of clamping screws 4.

For this purpose, the clamping screws 4 are passed through a clamping ring 5 arranged opposite the hub flange 2, through a connecting flange 12 assigned to each clamping screw 4 by means of the friction ring 7, and through the hub flange 2, wherein the connecting flange 12 has a through-opening 6 for passing through the clamping screws 4 and is clamped between the clamping ring 5 and the hub flange 2.

In the region of each through-opening 6, a radial groove 11 is provided in the connecting flange 12, which radial groove, in the exemplary embodiment shown in fig. 1, extends from the through-opening 6 outward relative to a reference circle diameter 13, on which reference circle diameter 13 the clamping screws 4 or the through-openings 6 are arranged symmetrically.

In the exemplary embodiment according to fig. 3 and 4, the respective radial groove 11, likewise starting from the through-opening 6, extends in an oriented manner inward in the direction of the center line of the hub 1.

The sliding element 8, in the form of a guide pin, is guided in a radial groove 11, the axis of which is parallel to the clamping screw 4, with its shank 9 being inserted in an axially fixed manner into an insertion opening 14 of the hub flange 2.

At its free end, a head 10 is formed, which preferably has a polygonal, in particular quadrangular or hexagonal, shape in cross section and at least two opposite parallel sides, which bear against corresponding side walls of the radial groove 11.

The temperature-induced radial expansion of the friction disks 7 can therefore be carried out without any difficulty, and since the through-opening 6 of the connecting flange 12 has a corresponding dimensional tolerance with respect to the shank of the clamping screw 4, there is also a sufficiently large clearance here. In this case, the centering of the friction disc 7 is ensured, since the slide 8 is fitted in the radial groove 11.

Fig. 5 and 6 show that the radial grooves 11 are arranged outside the through-hole 6 from the side facing the hub 1. In the exemplary embodiment shown in fig. 5, the radial groove 11 is formed in a web 15 formed on the side of the connecting flange 12, which ends at a distance from the hub 1 and enables particularly easy mounting of the sliding element.

Fig. 7 shows an example of a design of the slide as a guide pin.

Example a) shows the simplest shape of such a sliding element designed as a cylindrical pin. For this purpose, for example, standard components can be used. b) The exemplary slide corresponds to the slide of fig. 3 and 4, in which a square head is connected to the cylindrical rod 9 and is inserted into a corresponding radial groove in the friction disk 7.

This is also the case for the slider shown in c), in which the head 10 inserted into the radial slot 11 has a hexagonal cross-section. The head 10 of example d) is of cylindrical design, as is its shaft 9.

The sliding elements b), c) and d) can be produced from semi-finished products, for example from square, hexagonal or round steel, on which the cylindrical shank 9 is turned.

In principle, it is entirely possible to use other suitable standard parts or correspondingly machined semi-finished products.

List of reference numerals

1 hub 2 hub flange 3 hub body 4 clamping screw 5 clamping ring 6 through hole 7 friction ring 8 slide block 9 rod 10 head 11 radial groove 12 connecting flange 13 pitch circle diameter 14 insertion hole 15 tab

Claims (15)

1. Brake disc comprising at least one friction ring (7) provided with radial grooves (11), which is fastened to a hub (1) or a wheel disc that can be fastened to a shaft by means of clamping screws (4), wherein, in order to prevent rotation and centre the friction ring (7), a sliding element (8) connected to the hub (1) or the wheel disc is inserted in the radial groove (11), characterized in that: each slide (8) is designed as a guide pin made of a semi-finished or standard part, which extends with its shaft (9) axis parallel to the clamping screw (4), and each slide (8) is arranged in an insertion opening (14) of the hub (1) or wheel disc.

2. Disc according to claim 1, characterized in that each radial groove (11) extends from a through hole (6) in the friction ring (7) through which a clamping screw (4) passes, either outwards or inwards towards the centre line of the hub (1).

3. Disc according to claim 1, characterized in that each sliding element (8) is arranged in a hub flange (2).

4. Disc according to one of claims 1 to 3, wherein each sliding element (8) has a head (10) which is guided in an associated radial groove (11).

5. A brake disc according to any one of claims 1 to 3, wherein each radial groove is less than or equal to 10 mm.

6. Brake disc according to one of claims 1 to 3, characterized in that the sliding elements (8) are designed as cylindrical pins.

7. Disc according to claim 4, characterized in that the head (10) of each slide (8) is of polygonal design.

8. Disc according to claim 7, characterized in that the head (10) of each slide (8) is of quadrangular or hexagonal design.

9. Disc according to claim 4, characterized in that the head (10) of each slide (8) has two sides extending parallel to each other and resting against the side walls of the respective associated radial groove (11).

10. Disc according to claim 7, characterized in that each sliding element (8) with a polygonal head is made of multi-ribbed steel, wherein the cylindrical bars (9) are cut.

11. Disc according to one of claims 1 to 3, wherein the sliding elements (8) are distributed symmetrically around the circumference.

12. A brake disc according to any of claims 1 to 3, wherein 3, 6, 9 or 12 sliding elements (8) are provided.

13. A brake disc according to any of claims 1 to 3, wherein more than 6 sliding elements (8) are provided.

14. A brake disc according to any one of claims 1 to 3, wherein the number of sliding elements (8) corresponds to the number of clamping screws (4).

15. Brake disc according to claim 1, wherein the brake disc is a brake disc for a rail vehicle.