JP2009287691A - Pad for disk brake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively prevent a partial fall of a friction material. <P>SOLUTION: This pad for disk brake 10 comprises a cup 14 formed into a cup-shape by a base part 20 and a side wall part 22, and a sintered friction material 16 held inside the cup 14 at an equal height to the side wall part 22. The cup 14 is made of a spherical graphite cast iron or a gray cast iron. The inner surface of the side wall part 22 of the cup 14 is provided with recessed and protruding parts for holding the sintered friction material 16 after a crack is generated. The recessed and protruding parts are formed to repeatedly appear in a direction for separating from the base part 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a disc brake pad of a vehicle.

Generally, a disc brake pad of a vehicle has a structure in which a friction material is fixed to a reinforcing plate or the like attached to a back metal as disclosed in, for example, Patent Documents 1 and 2 below. Specifically, in the brake pad of Patent Document 1, the friction material is sintered in a state where it is assembled to the reinforcing plate, and it is fastened to the back metal by rivets. On the other hand, in the brake pad of Patent Document 2, a rough ground support covered with a rough ground is welded to a back metal, and a friction material is pressed on the rough ground support.
Japanese Patent Laid-Open No. 7-158673 Special table 2004-522118 gazette

  In the brake pad disclosed in the above-mentioned patent document, by providing a reinforcing plate or a rough ground support, the friction material itself does not come off from these reinforcing plates and the like. However, for example, when using a sintered material in which various substances are dispersed in the base material as the friction material, the thermal expansion coefficient of the dispersed material is different from that of the base material. May be peeled off, and cracks may be generated in the middle portion in the thickness direction of the friction material. In this case, in these brake pads, although the joint portion of the reinforcing plate or the rough ground support and the friction material is firmly bonded, it is difficult to prevent a part of the friction surface side of the friction material from falling off. It is. In other words, when the friction material receives a shearing force during braking and a crack is generated in the direction along the back metal, the crack gradually develops due to continued use. There is a risk of separation and dropout.

  Therefore, the present invention has been made in view of such a point, and an object of the present invention is to effectively prevent partial loss of a friction material in a disc brake pad.

  In order to achieve the above object, the present invention provides a cup formed in a cup shape by a base portion and a side wall portion, and a sintered body held at the same height as the side wall portion inside the cup. A disc brake pad comprising a friction material.

  In the present invention, since the sintered friction material is held in a cup having a side wall portion having the same height as that of the sintered friction material, a shear force is applied to the sintered friction material by the frictional force with the disk. Even if it occurs, its size can be reduced. And since the sintered friction material is hold | maintained at the cup, even if a crack generate | occur | produces in a sintered friction material, it can prevent that a sintered friction material falls and scatters.

  Here, the cup is preferably made of spheroidal graphite cast iron or gray cast iron. In this embodiment, the steel disk can be made less likely to be damaged.

  In this aspect, it is more preferable that the side wall portion of the cup is provided with a hook structure for holding the sintered friction material after generation of cracks. In this aspect, even if a crack is generated in the sintered friction material and a part of the sintered friction material is separated, the part of the separated sintered material is separated by the hook structure of the cup side wall. The friction material is retained. For this reason, it is possible to surely prevent the sintered friction material separated by cracks from falling off and divergence.

  The hook structure may be unevenness formed so as to repeatedly appear toward the direction away from the base portion on the inner surface of the side wall portion to which the sintered friction material is joined. In this aspect, when a crack is generated in the sintered friction material and a part of the sintered friction material is separated, the separated part of the sintered friction material is caught by the unevenness and held. The Moreover, since the unevenness is repeatedly formed in a direction away from the base portion, the unevenness will not disappear even if the side wall portion of the cup is gradually worn away. Therefore, even if the side wall portion of the cup gradually wears out, it is possible to reliably prevent a part of the sintered friction material separated by the cracks from dropping and divergence.

  It is preferable that the internal angle of the concave portion constituting the concave and convex is an obtuse angle. In this aspect, the apex angle of the sintered friction material joined to the concave portion of the side wall portion of the cup becomes an obtuse angle. For this reason, the apex angle portion of the sintered friction material does not become an acute angle, and can have a certain volume. Therefore, it is possible to effectively prevent the vertical angle portion of the sintered friction material from cracking and falling off.

  The hook structure may be a taper structure formed on the inner surface of the side wall portion to which the sintered friction material is bonded so as to be inclined so that the inner surfaces facing each other approach each other as the distance from the base portion increases. Good. In this aspect, the outer dimension of the sintered friction material becomes a structure that gradually decreases as the distance from the base portion increases. For this reason, when a crack occurs in the sintered friction material and a part of the sintered friction material is separated, the separated part of the sintered friction material falls off and diverges due to the taper structure. Is reliably prevented. In addition, since the tapered structure is continuously inclined from the base portion toward the distal end side of the side wall portion, the tapered structure does not disappear even if the side wall portion of the cup is gradually worn away. Therefore, even if the side wall portion of the cup gradually wears out, it is possible to reliably prevent a part of the sintered friction material separated by the cracks from dropping and divergence.

  When the disc brake pad has a back metal and a fastener for fastening the base part to the back metal, an insertion hole for allowing the fastener to be inserted is formed in the sintered friction material. May be. In this aspect, since the base portion can be fastened to the back metal by inserting the fastener through the insertion hole, the burden of fixing the cup can be reduced.

  In this aspect, it is preferable that the cross sectional area of the sintered friction material and the side wall portion is constant at an arbitrary position in the height direction. In this aspect, since the cross-sectional area of the sintered friction material and the side wall portion is constant at an arbitrary position in the height direction, it is possible to prevent stress concentration from occurring in the sintered friction material and the side wall portion. Accordingly, the hooked structure can prevent the sintered friction material from falling off and scattering after the occurrence of cracks, and more reliably prevent the sintered friction material receiving the shearing force and breakage due to stress concentration on the side wall portion.

  As described above, according to the present invention, it is possible to effectively prevent the friction material from partially falling off.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  1 and 2 show an embodiment of a disc brake pad according to the present invention. 2 is a cross-sectional view taken along line II-II in FIG. The disc brake pad 10 is a brake pad that can be applied to a high-speed train such as a Shinkansen.

  The disc brake pad 10 includes a backing metal 12, a cup 14 attached to the backing metal 12, and a sintered friction material 16 fixed to the cup 14. The back metal 12 is for fixing the cup 14, and is formed in an elongated flat plate shape extending in one direction. The back metal 12 and the cup 14 are made of an iron-based material having iron as a base material.

  The back metal 12 is provided with a number of fastening holes 12 a for fastening the cup 14. The fastening holes 12a are arranged at equal intervals in the longitudinal direction of the back metal 12, and are alternately arranged in two rows.

  The cup 14 is provided corresponding to each fastening hole 12a. The cup 14 is made of spheroidal graphite cast iron or gray cast iron. The cup 14 integrally has a circular flat plate-shaped base portion 20 and a side wall portion 22 erected on the periphery of the base portion 20 and is formed in a cup shape. A through-hole 20 a that penetrates in the thickness direction is provided at the center of the base portion 20.

  A rivet 24 as a fastener is inserted from the fastening hole 12 a of the back metal 12 to the through hole 20 a of the cup 14. The rivet 24 is a head having an enlarged diameter at both ends, and the cup 14 is fixed to the back metal 12.

  The sintered friction material 16 is provided in each cup 14. The sintered friction material 16 is disposed on the inner side of the cup 14 and is formed at the same height as the side wall portion 22. The front end surface (upper end surface in FIG. 2) of the sintered friction material 16 is a friction surface. The friction surface is pressed against a steel brake disc (not shown) to become a sliding surface that slides against the brake disc.

  The sintered friction material 16 is formed with an insertion hole 16a through which the head of the rivet 24 can be inserted. The insertion hole 16 a has a circular cross section, and penetrates in the height direction at the center of the sintered friction material 16. For this reason, when attaching the cup 14 to the back metal 12, the rivet 24 can be inserted into the insertion hole 16 a of the sintered friction material 16 and inserted into the fastening hole 12 a of the back metal 12. In order to fix the sintered friction material 16 to the cup 14, the powdery sintered material is poured into the cup 14 with the insertion hole 16a remaining, and the sintered material is pressed and hardened. Good.

  The sintered friction material 16 is made of a copper alloy, that is, a copper-based material having copper as a base material, and a small amount of additives such as a metal compound such as iron and graphite are dispersed so that a high friction coefficient can be obtained even at a high temperature. It is comprised by the sintered metal made. The hardness of the cup 14 is lower than that of the disk, similarly to the hardness of the sintered friction material 16. Therefore, when the sintered friction material 16 is worn by friction with the disk, the side wall portion 22 of the cup 14 is also worn in the same manner.

  The side wall portion 22 of the cup 14 is provided with a hook structure 28 that can hold the sintered friction material 16 even after a crack has occurred. In the present embodiment, the hook structure 28 is an unevenness formed on the inner surface of the side wall portion 22. Specifically, as shown in FIG. 3, the irregularities are formed such that the concave portions 28a and the convex portions 28b repeatedly appear in the height direction of the side wall portion 22, and the concave portions 28a and the convex portions 28b are formed as follows. Each of the vertical cross sections of the side wall portions 22 is configured by combining linear inclined lines inclined in opposite directions. And the recessed part 28a and the convex part 28b are extended in the circumferential direction, respectively. In addition, even if the unevenness | corrugation is formed in the helical form, the structure by which the recessed part 28a and the convex part 28b which are extended in a horizontal direction are formed in the height direction in the state which each became independent may be sufficient. When the concave portion 28a and the convex portion 28b are formed in a spiral shape, the concave portion 28a and the convex portion 28b are formed by one concave portion 28a and the convex portion 28b that are continuous from the distal end to the base end of the side wall portion 22, respectively. It becomes the composition.

  As shown in FIG. 3, it is preferable that the interior angle of the recess 28a is an obtuse angle. If the inner angle of the concave portion 28a is an obtuse angle, the apex angle of the protruding protrusion of the sintered friction material 16 corresponding to the concave portion 28a becomes an obtuse angle, and this protruding portion can have a certain volume. Separation can be prevented. Furthermore, if comprised in this way, the stress concentration of this protrusion part can be relieve | moderated and a crack and the crack generation itself can also be prevented. If constituted in this way, it can also be filled with a powdery sintered material into this protruding part easily and reliably at the time of sintering. In order to effectively exhibit the holding performance, the inner angle of the recess 28a is more preferably about 110 to 130 degrees. In the present embodiment, the inner angle of the recess 28a is 120 degrees. Note that the thickness of the side wall portion 22 is 4 mm, and the height of the convex portion 28b (the difference between the vertex of the convex portion 28b and the vertex of the concave portion 28a) is 1 mm. Further, four recesses 28a are formed in the height direction.

  As described above, according to the present embodiment, the sintered friction material 16 is held by the cup 14 having the side wall portion 22 having the same height as the sintered friction material 16. Even if shear force is sometimes generated in the sintered friction material 16 due to the frictional force with the disk, the magnitude can be reduced. And since the sintered friction material 16 is hold | maintained at the cup 14, even if a crack generate | occur | produces in the sintered friction material 16, it can prevent that the sintered friction material 16 falls off and disperses.

  In particular, in order to apply to high-speed trains, the frictional heat becomes high, so it is important to secure a coefficient of friction in the high temperature region as the sintered friction material 16, and the type and amount of additives are also selected from that viewpoint. Therefore, in some cases, it may be necessary to use a sintered friction material 16 that does not have sufficient toughness in a high temperature region. Even in such a case, in the disc brake pad 10 of the present embodiment, it is possible to prevent a part of the sintered friction material 16 from dropping or scattering due to the presence of the cup 14. In other words, in the disc brake pad 10 of the present embodiment, the cup 14 can prevent the sintered friction material 16 from falling off, so that the degree of freedom in selecting the material such as the type and amount of additive is increased. Can do.

  In addition, in the present embodiment, since the hook structure 28 is provided on the side wall portion 22 of the cup 14, a crack is generated in the sintered friction material 16, and a part of the sintered friction material 16 is separated. Even if it becomes, the part of the separated sintered friction material 16 is held by the hook structure 28 of the cup side wall 22. For this reason, it is possible to reliably prevent the sinter friction material 16 separated by cracks from falling off and diverging.

  Further, in the present embodiment, the hook structure 28 has unevenness that is repeatedly formed in the direction away from the base portion 20, so that a crack is generated in the sintered friction material 16 and a part of the sintered friction material 16 is formed. In the separated state, a part of the separated sintered friction material 16 is caught by the unevenness and held. Moreover, since the unevenness is repeatedly formed in the direction away from the base portion 20, even if the side wall portion 22 of the cup 14 is gradually worn away, the unevenness will not disappear. Therefore, even if the side wall portion 22 of the cup 14 is gradually worn away, it is possible to reliably prevent a part of the sintered friction material 16 separated by the cracks from dropping off and spreading.

  Furthermore, in this embodiment, since the interior angle of the recess 28a constituting the unevenness is an obtuse angle, the apex angle of the sintered friction material 16 joined to the recess 28a of the side wall portion 22 of the cup 14 becomes an obtuse angle. For this reason, the apex angle portion of the sintered friction material 16 does not become an acute angle, and this portion can have a certain volume. Therefore, it is possible to effectively prevent the vertical angle portion of the sintered friction material 16 from cracking and falling off. Furthermore, if constituted in this way, the powdery sintered material can be filled into the protruding portion easily and surely during sintering.

  In this embodiment, since the cup 14 is made of spheroidal graphite cast iron or gray cast iron, it is possible to make it difficult to damage the disc. That is, since spheroidal graphite cast iron and gray cast iron contain graphite in the composition, when viewed microscopically, graphite that is dispersed on the surface even when part of the side wall portion 22 is worn is always present between the disc. . Even if the hardness of the material is low, the side wall portion 22 made of spheroidal graphite cast iron and gray cast iron is not fused to the disk as compared with the case where the composition does not contain any graphite or the amount of the material is small. It is difficult to damage the disc.

  Further, in this embodiment, since the rivet 24 can be inserted into the insertion hole of the sintered friction material 16 and the base portion 20 can be fastened to the back metal 12, the burden of fixing the cup 14 can be reduced.

  Further, in this embodiment, since the cross-sectional area of the sintered friction material 16 and the side wall portion 22 is constant at an arbitrary position in the height direction, stress concentration is prevented from occurring in the sintered friction material 16 and the side wall portion 22. can do. Therefore, the fracture of the sintered friction material 16 and the side wall portion 22 that receives a shearing force can be prevented more reliably.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the spirit of the present invention. For example, as shown in FIG. 4, the hooking structure 28 of the side wall portion 22 may be a tapered structure formed in an inclined shape. The inner surface of the side wall portion 22 is inclined so as to gradually approach the opposing inner surface as it goes from the base portion 20 to the tip portion. In other words, the outer diameter of the sintered friction material 16 is gradually increased from the front end portion toward the base portion side.

  In this aspect, the outer dimension of the sintered friction material 16 becomes a structure that gradually decreases as the distance from the base portion 20 increases. For this reason, when a crack occurs in the sintered friction material 16 and a part of the sintered friction material 16 is separated, the separated part of the sintered friction material 16 has a tapered side wall. Since it is held by the portion 22, the sintered friction material 16 is reliably prevented from falling off and divergence. In addition, since the tapered structure is continuously inclined from the base portion 20 toward the distal end side of the side wall portion 22, even if the side wall portion 22 of the cup 14 is gradually worn away, the tapered structure disappears. There is nothing. Therefore, even if the side wall portion 22 of the cup 14 is gradually worn away, it is possible to reliably prevent a part of the sintered friction material 16 separated by the cracks from dropping off and spreading.

  In the embodiment and other embodiments, the cup 14 is fixed to the back metal 12 so as not to move. Instead, the cup 14 is attached to the back metal 12 so as to follow the inclination of the disk. It is good.

1 is a front view of a disc brake pad according to an embodiment of the present invention. It is sectional drawing in the II-II line of FIG. It is a figure which expands and shows the cup in the III section of FIG. It is a figure which shows partially the pad for disc brakes which concerns on other embodiment of this invention.

Explanation of symbols

12 Back metal 12a Fastening hole 14 Cup 16 Sintered friction material 16a Insertion hole 20 Base part 20a Through hole 22 Side wall part 24 Rivet (an example of a fastener)
28 Hook structure 28a Concave portion 28b Convex portion

Claims (8)

A cup formed in a cup shape by the base portion and the side wall portion;
A disc brake pad comprising: a sintered friction material that is held at the same height as the side wall portion and is held inside the cup.   The disc brake pad according to claim 1, wherein the cup is made of spheroidal graphite cast iron or gray cast iron.   The disc brake pad according to claim 2, wherein a hook structure for holding the sintered friction material after generation of a crack is provided on a side wall portion of the cup.   The disc brake according to claim 3, wherein the hook structure is an unevenness formed so as to repeatedly appear in an inner surface of the side wall portion to which the sintered friction material is joined in a direction away from the base portion. pad.   The disc brake pad according to claim 4, wherein an inner angle of the concave portion constituting the concave and convex portions is an obtuse angle.   The hook structure is a tapered structure formed on the inner surface of the side wall portion to which the sintered friction material is joined so as to be inclined so that the inner surfaces facing each other approach each other as the distance from the base portion increases. 3. The disc brake pad according to 3. With the back metal,
A fastener for fastening the base portion to the back metal,
The disc brake pad according to claim 4 or 6, wherein an insertion hole for inserting the fastener is formed in the sintered friction material.   The disk brake pad according to claim 7, wherein a cross-sectional area of the sintered friction material and the side wall portion is constant at an arbitrary position in the height direction.

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