BRAKE PAD FOR A DISK BRAKE SYSTEM AND DISK BRAKE SYSTEM

Abstract

The invention relates to a brake pad for a disk brake system, comprising a backplate, the backplate being delimited by two opposing lateral surfaces and an edge comprising a leading edge and a trailing edge of the backplate, wherein a friction layer is attached to one of said lateral surfaces. The backplate comprises two hammerheads extending in a plane defined by the backplate, a leading hammerhead of the two hammerheads protruding from an outer end of the leading edge of the backplate and a trailing hammerhead of the two hammerheads protruding from an outer end of the trailing edge of the backplate.

Claims

1. A brake pad for a disk brake system, comprising a backplate, the backplate being delimited by two opposing lateral surfaces and an edge comprising a leading edge and a trailing edge of the backplate, wherein a friction layer is attached to one of said lateral surfaces, and wherein the backplate comprises two hammerheads extending in a plane defined by the backplate, a leading hammerhead of the two hammerheads protruding from an outer end of the leading edge of the backplate and a trailing hammerhead of the two hammerheads protruding from an outer end of the trailing edge of the backplate, and wherein the edge of the backplate comprises a chamfer between an inner edge of the leading hammerhead and the leading edge, where the edge of the backplate runs at a non-vanishing angle with respect to the inner edge of the leading hammerhead and with respect to the leading edge, characterized in that a clip having a U-shape is attached to the chamfer, the clip being formed of a strip consisting of a central portion forming a base of the U-shape and two end portions forming two opposite arms of the U-shape, wherein the central portion rests on the chamfer and the two end portions rest on the opposing lateral surfaces of the backplate.

2. The brake pad of claim 1, wherein a width of the clip is smaller than or equal to a width of the chamfer.

3. The brake pad of claim 1, wherein the strip forming the clip has a width of between 2 mm and 10 mm and/or a thickness of between 0.5 mm and 3 mm.

4. The brake pad of claim 1, wherein the two end portions of the clip have a length of at least 3 mm and/or at most 10 mm.

5. The brake pad of claim 1, wherein the clip is made of materials comprising a metal and/or an elastomer.

6. The brake pad of claim 1, wherein the clip comprises a metal layer and an elastomer forming an outer surface of the clip.

7. The brake pad of claim 1, wherein the clip is glued to the backplate.

8. The brake pad of claim 1, wherein the non-vanishing angle between the chamfer and the inner edge of the leading hammerhead lies between 30 and 60.

9. A disk brake system for a vehicle, comprising two brake pads according to any of the preceding claims, a brake disk with two opposing surfaces, a caliper, movably holding the two brake pads on opposite sides of the brake disk, the brake pads being configured to be pressed against the opposing surfaces of the brake disk for braking, a leading edge stop and a trailing edge stop provided at a distance from the brake disk, wherein, the brake pads are movably held between the leading edge stop and the trailing edge stop, such that, upon braking during a forward movement of the vehicle, the brake pads engaging with the brake disk move along with the brake disk until the trailing edges of the brake pads abut against the trailing edge stop, and, upon braking during a backward movement of the vehicle, the brake pads engaging with the brake disk move along with the brake disk until the leading edges of the brake pads and the clips attached to the chamfers of the brake pads abut against the leading edge stop.

10. A disk brake system according to claim 9, wherein the clip is in contact with the leading edge stop in a non-braking condition.

11. A disk brake system according to claim 9, comprising a knuckle which holds the caliper and comprises a first knuckle finger forming the leading edge stop and a second knuckle finger forming the trailing edge stop.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Therein

[0028] FIG. 1 shows an exploded view of a disk brake system,

[0029] FIG. 2 shows a detailed view of a portion of the brake system, exposing a brake pad abutting against a knuckle finger,

[0030] FIG. 3 shows a lateral view of the brake pad,

[0031] FIG. 4a shows a lateral view of a leading portion of a brake pad,

[0032] FIG. 4b shows the lateral view from FIG. 4a, with a clip attached to the brake pad,

[0033] FIG. 4c shows the brake pad as shown in FIG. 4b, the brake pad and the clip abutting against the knuckle finger,

[0034] FIG. 5a shows a front view of the clip, and

[0035] FIG. 5b shows a perspective view of the clip.

DETAILED DESCRIPTIONS

[0036] FIG. 1 shows an exploded view of a disk brake system 1000 for a vehicle. The disk brake system comprises a brake disk 200, a knuckle 300, a caliper 400 and two brake pads 100, 100.

[0037] The two brake pads 100, 100 exhibit essentially the same setup but are mirrored with respect to each other. To distinguish between the two brake pads, reference numerals pertaining to a second brake pad 100 of the two brake pads 100, 100 are hyphenated. All of the features discussed herein in the context of one of the brake pads 100, 100 apply for both brake pads 100, 100 unless stated otherwise.

[0038] The brake disk 200 is rotatably connected to the knuckle 300. A rotating direction of the brake disk 200 corresponding to a forward movement is illustrated in FIG. 1 by means of an arrow labelled with the letter F. The knuckle 300 comprises two knuckle fingers 310, 320, arranged at a substantially equal distance from the brake disk and extending orthogonally to a plane defined by the brake disk. The caliper 400 and the two brake pads 100, 100 are arranged between the two knuckle fingers 310, 320. The caliper 400 holds the two brake pads 100, 100 on opposite sides of the brake disk, the brake pads 100, 100 being movably connected to the caliper 400 by means of a piston such that they can be pressed against opposing surfaces 210, 220 of the brake disk 200 for braking.

[0039] The brake pads 100, 100 each comprise a backplate 110, 110 which is in each case delimited by two opposing lateral surfaces 111, 111, 112, 112 and an edge 113, 113. Friction layers 130, 130 are in each case attached to one 112, 112 of the surfaces 111, 111, 112, 112. When the brake pads 100, 100 are pressed against the brake disk 200, their respective friction layers 130, 130 engage with the brake disk 200. The physical properties of the friction layers 130, 130 are tuned to optimize braking performance when the friction layers 130, 130 engage with the brake disk 200.

[0040] In the setup as shown in FIG. 1, upon braking during a forward movement of the vehicle (the brake disk 300 rotating in the direction of the arrow F), a portion of the brake disk 200 entering in contact with the brake pads 100, 100 engages at first with the uppermost section of the friction layers 130, 130. Said portion of the brake disk 200 then slides along the friction layers 130, 130, from top to bottom. Therefore, the upper side of the brake pads 100, 100, as depicted in FIG. 1, is referred to as the leading side L and the lower side of the brake pads is referred to as the trailing side T. The terms leading and trailing are used herein to refer to the parts lying on a particular one of these sides.

[0041] As the brake pads 100, 100 are movably arranged between the knuckle fingers 310, 320, upon engagement with the brake disk 200 during braking, they will be dragged along with the brake disk 200 until they abut against one of the knuckle fingers 310, 320. The knuckle fingers 310, 320 thus act as stops for the brake pads 100, 100. When braking during the forward movement of the vehicle, a trailing edge 119, 119 of the backplates 110, 110 will abut against the bottom one of the knuckle fingers, referred to as the trailing knuckle finger 320. If the direction of movement of the vehicle and thus the rotating direction are altered and the brakes are applied anew, the brake pads 100, 100 are dragged back up towards the upper knuckle finger, referred to as the leading knuckle finger 310. The leading knuckle finger 310 thus acts as a stop for a leading edge 115, 115 of the backplates 110, 110. In particular when applying the brakes for the first time after the rotating direction of the brake disk 200 has been altered, the brake pads 100, 100 will move from one of the knuckle fingers to the other, resulting in an undesired clicking noise.

[0042] It is an object of the present invention to avoid such a clicking noise. It will be explained in the context of the following figures, how the clicking noise is advantageously avoided according to this application.

[0043] It should also be noted that the backplates 110, 110 of the brake pads 100, 100 comprise so-called hammerheads 114, 114, 118, 118. Corresponding to the previously introduced nomenclature, it is herein referred to leading hammerheads 114, 114 and trailing hammerheads 118, 118. The hammerheads 114, 114, 118, 118 form a part of the backplates 110, 110 and protrude at outer ends of the leading and trailing edges of the backplates 110, 110, respectively. The hammerheads 114, 114 118, 118 ensure safe abutment of the edges 113, 113 of the backplates 110, 110 against the knuckle fingers 310, 320. The term outer end is defined with respect to the brake disk 200, i.e., is to be understood as radially outward.

[0044] FIG. 2 shows an enlarged view of a section of the disk brake system from FIG. 1 in an assembled state. Therein, part of the caliper 400, part of the brake disk 200, and part of the leading side L of the brake pad 100 is shown. The leading hammerhead 114 can be seen, as it rests against the leading knuckle finger 310 representing the leading edge stop. This configuration is for instance typical during braking when the vehicle is moving in a backward direction. A U-shaped clip 500 is glued to the backplate 110 of the brake pad 100 near the leading hammerhead 114. The clip 500 extends over portions of the lateral surfaces 111, 112 of the backplate 110 and across the edge 113 of the backplate. The clip 500 also contacts the leading knuckle finger 310. The clip has an influence of the impact of the brake pad 100 onto the knuckle finger 310. It limits the movement of the brake pad 100 and has a surface made of a material that is softer than that of the leading edge, resulting in damping of the clicking noise.

[0045] FIG. 3 shows the brake pad 100 from the previous figures in a side view in greater detail. The lateral surface 112 which holds the friction layer 130 is visible. An arrow labelled by the letter F indicates the rotating direction of the brake disk 200 for forward movement of the vehicle, allowing for the definition of the leading side L and the trailing side T of the brake pad 100.

[0046] The edge 113 runs about the entire backplate 110, including the leading hammerhead 114 and the trailing hammerhead 118. The edge of the backplate thereby runs substantially orthogonal to the planes defined by the lateral surfaces of the backplate. The edge 113 comprises the leading edge 115 and the trailing edge 119 of the backplate 110. The leading edge 115 and trailing edge 119 represent the areas predominantly subject to force upon impact of the brake pad 100 onto one of the stops 310, 320.

[0047] It can be seen from FIG. 3 that the two hammerheads 114, 118 extend in a plane defined by the backplate 110, the leading hammerhead 114 protruding from an outer end of the leading edge 115 of the backplate 110 and a trailing hammerhead 118 protruding from an outer end of the trailing edge 119 of the backplate 110, the outer ends once again being defined with respect to the brake disk 200.

[0048] The chamfer 116 is covered by the clip 500. The chamfer 116 lies between an inner edge 117 of the leading hammerhead 114 and the leading edge 115 of the backplate 100. At the chamfer 116, the edge 113 of the backplate 110 runs at a non-vanishing angle with respect to the inner edge 117 of the leading hammerhead 114 and with respect to the leading edge 115.

[0049] A trailing side of the brake pad 100 has a setup identical to that of the leading side, with a further chamfer 120 lying between the trailing edge 119 and an inner edge 121 of the trailing hammerhead 118. No clip is provided on the trailing side.

[0050] For both chamfers 116, 119, an angle with respect to the inner edge 117 of the leading hammerhead 114 lies between 30 and 60, is in particular approximately 45.

[0051] FIGS. 4 a to c show a side view of part of the leading side of the backplate 100. The opposite side from the view of FIG. 3 is shown.

[0052] In FIG. 4a, the leading side is shown before the clip 500 is attached thereto, exposing the chamfer 116 lying between the inner edge 117 of the leading hammerhead 118 and the leading edge 115. A width w.sub.1 of the chamfer 116, extending between the inner edge 117 of the leading hammerhead 118 and the leading edge 115 is marked in FIG. 4a.

[0053] In FIG. 4b, the clip 500 is glued to the backplate 110 in the region of the chamfer 116, the clip 500 covering the chamfer 116. A width w.sub.2 of the clip 500 is indicated in the Figure and is identical to or smaller than the width w.sub.1 of the chamfer 116.

[0054] FIG. 4c shows the setup of FIG. 4b in a non-braking condition, wherein the leading edge 115 but part of the clip 500 remains in contact with the leading knuckle finger 310. When braking during a backward-movement of the vehicle, the leading edge 115 moves towards the knuckle finger 310 and finally abuts against the knuckle finger 310, wherein the clip 500 provides damping during the impact.

[0055] FIGS. 5 a and b show the clip 500, which dip 500 has already been discussed in the context of the previous figures. FIG. 5a displays the clip 500 in a side view and FIG. 5b in a perspective view.

[0056] The clip 500 is formed of a strip which has a U-shape. The strip consists of a central portion forming a base of the U-shape and two end portions 540, 550 forming two opposite arms of the U-shape. The central portion 530 is configured to rest on the chamfer 116 and the two end portions 540, 550 to rest on the opposing lateral surfaces 111, 112 of the backplate. A length of the central portion, i.e. a distance between the arms of the U-shape, is therefore chosen to be identical to a thickness of the backplate 100.

[0057] A width of the clip 500 is chosen to be approximately equal to the width of the chamfer 116, but not larger than the width of the chamfer 116.

[0058] The strip forming the clip 500 has a width of between 2 mm and 7 mm and a thickness of between 0.5 mm and 3 mm.

[0059] The two end portions 540, 550 have a length of between 3 mm and 10 mm.

[0060] The clip 500 comprises steel and rubber, steel being provided on an inner side 520 of the clip 500 to ensure sufficient stability and robustness of the clip 500 and provide a surface which can be glued to the backplate 110. A rubber layer is provided on an outer side 510 of the clip 500 and forms an outer surface of the clip. The rubber layer provides damping when the dip impacts onto the stop.

LIST OF REFERENCE NUMERALS

[0061] 1000 Disk brake system [0062] 100, 100 Brake pad [0063] 110, 110 Backplate [0064] 111, 112, [0065] 111, 112 Surfaces of the backplate [0066] 113, 113 Edge of the backplate [0067] 114, 114 Leading hammerhead [0068] 115, 115 Leading edge [0069] 116, 116 Chamfer [0070] 117, 117 Inner edge of the leading hammerhead [0071] 118, 118 Trailing hammerhead [0072] 119, 119 Trailing edge [0073] 120, 120 Further chamfer [0074] 121, 121 Inner edge of the trailing hammerhead [0075] 130, 130 Friction layer [0076] 200 Brake disk [0077] 210, 220 Opposing surfaces of the brake disk [0078] 300 Knuckle [0079] 310 Leading edge stop [0080] 320 Trailing edge stop [0081] 400 Caliper [0082] 500, 500 Clip [0083] 510 Outer side of the clip [0084] 520 Inner side of the clip [0085] 530 Central portion of the clip [0086] 540, 550 End portions of the clip [0087] F Rotating direction for forward movement [0088] L Leading portion of the brake pad [0089] T Trailing portion of the brake pad