CN107989931A - Brake pad and rail vehicle - Google Patents

Abstract

The invention provides a brake pad for a rail vehicle (10) having a brake disc and a rail vehicle. The brake pad comprises at least one friction element (100) non-rigidly attached to the pad carrier (20). The friction element (100) includes a friction surface (105) that contacts a brake disc during braking to provide a friction force acting along a friction line (110) on the friction surface (105). The friction element (100) comprises at least one groove (130) extending along the friction surface (105) non-parallel to frictional forces acting during braking of the rail vehicle (10), wherein the at least A groove (130) is arranged symmetrically or asymmetrically with respect to the geometric center of said friction surface (105).

Description

Brake pads and rail vehicles

technical field

The invention relates to a brake pad, and in particular to a brake pad for a rail vehicle, having a sintered friction element with at least one groove.

Background technique

Each brake pad for a rail vehicle may have one or more friction elements held by a pad carrier. During braking action, all friction elements will ideally contact the brake disc with their entire friction surface. The friction elements can be rigidly or removably attached to the pad carrier to ensure an even load distribution on the brake disc.

When friction elements contact metal brake discs, so-called metal pickup (wear material from the brake disc) occurs and reduces the braking efficiency of conventional friction elements and can also damage the brake disc. Also, water or moisture on the brake disc reduces the friction between the friction elements and the brake disc.

There are no solutions available for these problems, and in view of the increasing demands in the braking systems of modern rail vehicles, the detrimental effects of abrasive materials are becoming increasingly significant. Accordingly, there is a continuing need to improve the friction performance of friction elements.

Contents of the invention

At least some of the above problems can be solved by the brake pad and rail vehicle provided by the present invention.

The invention relates to a brake pad for a rail vehicle having a brake disc. The brake pad includes at least one friction element non-rigidly attached to the pad carrier, the friction element including a friction surface that contacts the brake disc during braking to provide a friction force along the friction surface The friction line above works. The friction element comprises at least one groove extending along the friction surface in a non-parallel manner to frictional forces acting during braking of the rail vehicle. The at least one groove is arranged symmetrically or asymmetrically with respect to the geometric center of the friction surface.

Optionally, the at least one groove is configured to collect and transport material along the friction line during braking.

Thus, according to the invention, the friction element comprises a groove extending on the friction surface to pick up material along the friction line or a plurality of grooves extending along the friction surface. Even if only a single groove is present, this groove can eg be arranged symmetrically or asymmetrically with respect to the geometric center of the friction surface.

It will be understood that the term "element" does not imply that there is only one element, but encompasses any number of elements. Thus, the term "groove" only limits the number of grooves to the extent that there is at least one groove. Furthermore, the term "non-rigidly" should be interpreted broadly such that it covers, at least to some extent, any relative movement (eg, tilting, pivoting, rotation) between the friction element and the pad carrier.

It will be understood that a friction line occurs when the friction element is attached to the brake pad carrier and the brake pad carrier and friction element together are pressed against the brake disc. The resulting friction will act along friction lines which can thus become visible. For example, a non-parallel arrangement between the grooves and the friction lines can provide the effect that material between the friction elements and the brake disc can be efficiently collected and conveyed. This material can be anything that reduces friction, for example, metal shavings or other abrasive material from the brake disc, as well as water, moisture, dust, etc.

It is also understood that the desired effects can be achieved in a variety of different ways. For example, the friction element may be configured to attach to the pad carrier in a predetermined manner such that the grooves will always be non-parallel to the friction line. It may also be possible that the rotation of the friction elements is prevented by the arrangement of other friction elements. For example, the friction elements may abut each other, thus preventing relative rotation, which ensures the desired alignment of the grooves. Another possibility is that the shape of the groove is modified (eg non-uniform) so that the circular friction line has to pass through the groove. A further possibility would be to arrange the plurality of grooves or the pattern of grooves independently of the rotational position of the friction elements on the pad carrier in order to ensure the desired effect.

Alternatively, the dimples may extend as holes through the friction element, at least partially housing attachment means for attaching the friction element to the pad carrier. Optionally, the attachment means are configured to attach the friction element to the pad carrier such that the grooves extend in a direction non-parallel to the friction line. It will be appreciated that the attachment means may be any means suitable for attaching the friction element to the pad carrier and includes, for example, a screw connection, a bolted connection with a fixed spring, or any means strong enough to dampen the forces occurring during braking application. other connections.

Optionally, the attachment means are configured to fix the friction element in rotation on the pad carrier or to allow a maximum rotation of eg 50° or 30° about an axis of rotation extending perpendicularly to the pad carrier.

Optionally, the attachment means is configured to movably attach the friction element to the pad carrier, enabling the friction surface to contact the brake disc with maximum surface area, thereby providing an evenly distributed pressure on the brake disc to avoid A local disk is overloaded.

The pad carrier may be configured to hold a plurality of friction elements in a predetermined position. In this case, one of the plurality of friction elements is shaped such that when rotated the friction element abuts another of the plurality of friction elements so that the friction element on the pad carrier can be rotated only to Maximum rotation angle (for example, 10° or 5°). For example, the shape of the friction element may be polygonal (eg, triangular, rectangular, pentagonal, hexagonal, octagonal, etc.) or circular or elliptical. Multiple friction elements may be arranged such that they resist rotation of a single friction element.

Optionally, the groove traverses the optional dimple and comprises a width in the range between 3 and 15 mm or between 4 and 10 mm. The width of the grooves may be modified to effectively collect or pick up wear material (eg, metal shavings) or water, moisture, or other materials and transport these materials to the edge portions of the friction elements.

Optionally, the angle between the direction of the groove and the friction line is in the angular range between 40° and 140°. The angle can be adjusted to facilitate efficient transport of collected material to the edge portion of the friction element.

The friction elements may be made of a sintered material suitable for providing a high level of friction when contacting the brake disc. The brake disc may comprise metal and may or may not be part of the rail vehicle wheel.

The invention also relates to a rail vehicle having a braking system comprising brake pads and a brake disc to brake the rail vehicle by pressing the friction surfaces of the friction elements against the brake disc, and the grooves do not Extends parallel to the braking force applied between the friction element and the brake disc.

Description of drawings

Some examples of friction elements and/or brake pads will be described below by way of example only and with reference to the accompanying drawings, in which:

Figure 1 shows a friction element according to an embodiment of the invention;

Figure 2 shows a brake pad with a plurality of friction elements according to an embodiment;

Figure 3 shows a partial view of the brake pad of Figure 2;

Figure 4 shows an enlarged view of a friction element;

5A, 5B show cross-sectional views through a friction element having symmetrical and asymmetrical grooves according to an embodiment; and

Figures 6A, 6B illustrate an embodiment where a plurality of grooves are arranged along a friction surface.

Figure 7 shows an embodiment for a brake pad.

Figure 8 shows another embodiment for a brake pad.

list of reference signs

20 brake pad carrier

100, 101, 102, 103 friction elements

105 friction surface

110 friction lines

120 Dimples or holes

125 Attachment

126 Back panel

127 bolt/dome element

130, 131, ... Groove

140 sintered material

210 coil spring

220 retaining spring

230 rocker element

Detailed ways

FIG. 1 shows a rectangular friction element 100 according to an embodiment of the invention. The friction element 100 is suitable for a rail vehicle having a brake pad carrier and a brake disc (not shown in FIG. 1 ). The friction element 100 is attachable to the pad carrier and includes a friction surface 105 which contacts the brake disc during braking to provide a friction force which follows a friction line 110 on the friction surface 105 of the friction element 100 effect. The friction element 100 includes: a dimple 120 in the friction surface 105 for attaching the friction element 100 to the pad carrier; and a groove 130 along the friction surface in a direction non-parallel to the friction line 110 extend.

As indicated in FIG. 1 , the friction line 110 extends along the friction surface 105 to form an angle α between the direction of the groove 130 and the friction line. The angle α may be in the range of 40° to 140°. In particular, the angle α may be chosen such that the friction line 110 is perpendicular (90°) to the direction of the groove 130 . The optional dimple 120 may be a through hole (e.g., having a diameter between 10 and 25 mm or about 16 mm) and may accommodate at least a portion of an attachment device (not shown in FIG. 1 ) to attach the friction element 100 to the brake. tablet carrier. The angle α can be ensured by suitable attachment of the friction element on the pad carrier, eg by preventing free rotation of the friction element on the pad carrier.

FIG. 2 shows a brake pad according to an embodiment with a pad carrier 20 on which a plurality of friction elements 100 are attached. Each of the friction elements 100 includes an optional recess 120 (indicated as a through hole) arranged in the middle of the friction element 100 in order to attach the friction element 100 to the pad carrier 20 . In this embodiment, friction element 100 comprises a polygonal (hexagonal in the illustrated embodiment) shape. The location of the attachment and the shape of the friction elements ensures that the friction elements 100 cannot rotate relative to each other, or can only rotate within a certain angular range (for example, between ±10°) about an axis of rotation, which can be arranged on the friction surface 105 on the geometric center.

The shown brake pad has the form of a circular arc adapted to contact a circular brake disc. The brake pad also comprises a first attachment portion 21 on the left hand side and a second attachment portion 22 on the right hand side, the two attachment portions 21 , 22 being configured to fix or guide the brake pad so that A brake actuator of an exemplary rail vehicle braking system is capable of actuating brake pads. The friction line thus extends between the first attachment portion 21 and the second attachment portion 22 as a circular portion. Thus, the shape and position of the friction elements 100 on the pad carrier 20 ensures that the grooves 130 in each of the friction elements 100 are substantially perpendicular to the friction line. Additionally, the circular brake disc provides centrifugal force that will transport collected metal debris/water away from the friction surface. As a result, friction increases.

FIG. 3 shows a partial view of the brake pad as shown in FIG. 2 . A plurality of friction elements 100 are still shown attached to the pad carrier 20 with optional dimples 120 formed as through holes for attaching the friction elements 100 to the pad carrier 20 . As is evident from Figure 3, the grooves 130 need not be aligned in the same direction, but there may be a range of possible angular directions along which the grooves 130 may extend. However, to provide the desired effect, it is advantageous when the angle between the groove 130 and the friction line 110 is such that the length of the friction line 110 along the friction surface 105 of each of the friction elements 100 is sufficiently short. These shortened friction lines 110 reduce exemplary metal pickup (or moisture) between the friction element 100 and the brake disc.

FIG. 4 shows an enlarged view of a friction element 100 surrounded by a plurality of further friction elements 101 , 102 , 103 . Friction element 100 includes sintered material 140 and attachment means 125 . Attachment means 125 are arranged on the rear side of the sintered material 140 (opposite the friction surface 105 ), are accessible through the through-hole 120 in the middle of the friction element 100 and provide attachment to the pad carrier 20 .

5A shows a sectional view through the friction element 100 along the section line A-A of FIG. The axis of rotation R passes through the bolt/dome element 127 which is part of the attachment device 125 and is arranged in the middle of the groove 130 .

FIG. 5B shows a similar friction element 100 . However, in this embodiment the grooves 130 are arranged asymmetrically with respect to the axis R of rotation. There is an offset between the axis of rotation R and the position of the groove 130 when viewed in the direction of the groove 130 .

In the two embodiments described above, the friction surface 105 is shown on the bottom of the sintered material 140 and the attachment means 125 is shown on the top. The cross section passes through a dimple 120 which is arranged approximately in the middle of the friction element 100 and is surrounded by a radially outwardly extending sintered material 140 . A groove 130 having a width W is shown within the dimple 120 and extends in a direction perpendicular to the plane of the drawing. The attachment device 125 is thus arranged on the face of the sintered material 140 on the side opposite the friction surface 105 . The attachment means 125 includes, for example, a back plate 126 and a bolt or dome member 127, wherein the bolt/dome member 127 may provide a joint that holds the back plate 126 on the pad carrier 20 (e.g., pivotable, rotating, or rigidly). Alternatively, the sintered material 140 may be fixed/sintered directly (rigidly) on the paddle carrier 20 or on the back plate 126 .

It will be appreciated that the arrangement of the grooves 130 is independent of the number of friction elements 100 arranged on the pad carrier 20 . Therefore, even if the brake pad has only a single friction element 100, this single friction element 100 can be formed as shown in FIG. 5A or FIG. 5B.

It is also understood that if instead of a single straight groove 130, multiple grooves or a pattern of grooves are formed on the friction surface 105, ensuring that at least one groove is not parallel to the friction line 110, collection and transfer can also be achieved The desired effect of picking up the material. The plurality of grooves may be arranged symmetrically or asymmetrically with respect to the point of rotation in the direction of the friction line. For asymmetric arrangements, this angle can be limited to 1-10°.

6A and 6B show (from different viewing directions) an embodiment for a friction element 100 in which not only a single groove is arranged along the friction surface 105 of the sintered material 140, but also a plurality of grooves 131, 132 along the friction surface 105 of the sintered material. The friction surface 105 of 140 is arranged. For example, the illustrated embodiment includes two grooves: a first groove 131 and a second groove 132 extending across the sintered material 140 and arranged at opposite sides of the axis of rotation R. on the side.

The embodiment of Fig. 6A shows the case where the first groove 131 and the second groove 132 are not parallel, while the embodiment of Fig. 6B shows a friction element in which the first groove 131 and the second groove 132 are parallel to each other. The angle between the first groove 131 and the second groove 132 may range, for example, between 0° to 10° (or at most 5° or at most 20°).

In further embodiments, more than two grooves may be arranged through the sintered material 140 . The advantage of having not only a single groove but a plurality of non-parallel grooves is that the arrangement of the friction elements 100 on the pad carrier 20 can be freely selected. In particular, if only a single friction element 100 is present on the pad carrier 20 , this offers the advantage that all grooves 130 are by no means parallel to the friction line 110 and thus the desired effect is achieved.

The manner of attaching the friction element 100 to the pad carrier by using the bolt/dome element 127 and the back plate 126 may be the same as that shown in Figures 5A, 5B. Furthermore, also as in the previous embodiments, the grooves 131, 132 do not pass through the entire sintered material 140 (see Figs. 6A, 6B). Note also that the embodiment of Figures 6A and 6B does not include any dimples or vias. The sintered material 140 is attached directly to the back panel 126 , for example by a sintering process which ensures a reliable attachment of the sintered material 140 . The back plate 126 may, for example, comprise metal to ensure reliable attachment to the paddle carrier 20 .

When the sintering material 140 is sintered on the back plate 126, the holes shown in the back plate 126 (see FIGS. 6A and 6B, upper left drawings) may be used to secure the back plate 126 during the sintering process.

The width W of the grooves 130, 131, 132 may be between 4mm and 10mm, or between 3mm and 20mm. This width W of the grooves 130, 131, 132 can be adjusted so that abrasive material and water can be collected by the grooves 130, 131, 132 to improve friction. This improvement is achieved by the interrupted contact of the friction element 100 to the brake disc caused by the grooves 130 , 131 , 132 (within the friction surface 105 of the element 100 only a shortening of the friction line 110 is possible).

FIG. 7 shows an embodiment for a brake pad in which the friction element 100 is attached directly to the pad carrier 20 using a bolt/dome element 127 . On the left-hand side, FIG. 7 shows a view of the brake pad carrier 20 with one friction element 100 , and on the right-hand side, FIG. 7 shows a sectional view through the section line shown on the left-hand side.

In particular, the pad carrier includes a plurality of holes through which the bolt 127 of each friction element 100 extends and is fixed on the opposite side of the pad carrier 20 by a fixing spring 220 . The sintered material 140 comprises at least one groove 130 which extends approximately perpendicularly to the longitudinal direction of the brake pad carrier 20 and thus runs non-parallel to the effective braking force when the brake is activated.

In addition, a coil spring 210 is disposed between the pad carrier 20 and the back plate 126, providing a pre-stress force, resulting in a gap between the pad carrier 20 and the back plate 126 in the absence of applied braking force. This play enables the tilting of the friction element 100 relative to the brake pad carrier 20 . Furthermore, the rear plate 126 has a spherical portion which allows tilting of the friction element 100 relative to the pad carrier 20 .

According to an embodiment, the friction element 100 may also be rotatable, at least to some extent, about an axis of rotation passing through the bolt 127 , but not movable perpendicular to the pad carrier 20 or in a lateral direction along the pad carrier 20 .

FIG. 8 shows a further embodiment for a brake pad, in which a rocker element 230 is arranged between the friction element 100 and the pad carrier 20 , but no coil spring 210 is provided. The rocker element 230 may provide a carrier for one or more friction elements 100 attached to the pad carrier 20 .

The friction element 100 is still fixed on the rear side of the brake pad carrier 20 by means of the fixing spring 220 and the spherical dome element 127 enables a tiltable attachment of the friction element 100 to the brake pad carrier 20 . This tilting is effected and limited by the gap formed between the rocker member 230 and the back panel 126 . Similarly, an additional gap may be formed between the rocker member 230 and the pad carrier 20 to enable tilting between the rocker member 230 and the pad carrier 20 . Alternatively, the plurality of friction elements 100 may be attached directly to the rocker element 230 which is secured to the pad carrier 20 . As a result, a set of friction elements 100 can be tilted together relative to the pad carrier 20 .

As already mentioned, the inclination of the at least one friction element 100 increases the frictional contact between the friction element and the brake disc, thereby improving the braking effect.

Embodiments of the present invention provide the following advantages:

Metal pick-up or any other material from the brake disc is reduced, since metal pick-up can only occur if the contact between the friction element and the brake disc is not interrupted (ie the friction line is long).

The transport of moisture or water away from the friction elements is improved and thus the friction during wet conditions is further improved.

The description and drawings merely illustrate the principles of the disclosure. It will thus be appreciated that those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the disclosure and are included within its scope.

Furthermore, although each embodiment may stand on its own as a discrete example, it should be noted that in other embodiments, defined features may be combined differently, i.e., particular features described in one embodiment may also be described in other embodiments. implemented in the embodiment. Such combinations are covered by the disclosure herein unless it is stated that a specific combination is not contemplated.

Claims (10)

CLAIMS 1. A brake pad for a rail vehicle (10) having a brake disc, said brake pad comprising at least one friction element (100) non-rigidly attached to a brake pad carrier (20), The friction element (100) comprises a friction surface (105) which is in contact with the brake disc during braking to provide a friction force along a friction line on the friction surface (105) (110) works, It is characterized in that, At least one groove (130) extending on said friction surface (105) is non-parallel to the friction line (110) of friction forces acting during braking of said rail vehicle (10), wherein said at least one The grooves (130) are arranged symmetrically or asymmetrically with respect to the geometric center of said friction surface (105). 2. The brake pad according to claim 1, characterized in that, The at least one groove (130) is configured to collect and convey material along the friction line (110) during braking. 3. The brake pad according to claim 1 or claim 2, characterized in that, the friction element (100) comprises: a sintered material (140) providing said friction surface (105) comprising said grooves (130) and comprising dimples (120); and attachment means (125) arranged on the face of the sintered material (140) opposite the friction surface (105) and at least partially accessible through the recess (120) Proximity, said attachment means (125) are adapted to attach said sintered material (140) to said brake pad carrier (20) such that said grooves (130) are ) in the direction of extension. 4. The brake pad according to claim 3, characterized in that, The attachment device (125) is configured to attach the sintered material (140) in a rotationally fixed manner to the brake pad carrier (20). 5. The brake pad according to claim 3 or claim 4, characterized in that, The attachment device (125) is configured to actively attach a sintered material (140) to the brake pad carrier (20). 6. Brake pad according to one of the preceding claims, wherein the pad carrier (20) is configured to hold a plurality of friction elements (100, 101, 102, 103) at a predetermined location, characterized by, The friction elements are shaped such that when the friction elements (100, 101, 102, 103) are attached to the pad carrier (20), one of the friction elements The element (100) abuts against another friction element (101, 102, 103) of the plurality of friction elements (100, 101, 102, 103) while rotating, thereby causing the pad carrier (20) to The friction element (100) can only be rotated to a maximum rotation angle. 7. The brake pad according to claim 6, characterized in that, The shape is polygonal, especially hexagonal or pentagonal. 8. Brake pad according to one of claims 3 to 7, characterized in that The groove (130) traverses the dimple (120) and includes a width (W) ranging between 3mm and 15mm or between 4mm and 10mm. 9. Brake pad according to one of the preceding claims, characterized in that The angle (α) between the direction of the groove (130) and the friction line (110) is in the angular range between 40° and 140°. 10. A rail vehicle, characterized in that the rail vehicle comprises: A brake pad according to any one of the preceding claims; and a brake disc for braking the rail vehicle by pressing the friction surface (105) of the friction element (100) against the brake disc, and the groove (130) The friction line runs non-parallel to the friction force exerted between the friction element (100) and the brake disc.