JP4973589B2 - Brake brake for vehicle drum brake - Google Patents

Description

  The present invention relates to a brake shoe for a vehicular drum brake that is pressed against an inner peripheral surface of a drum to generate a braking force. In particular, the present invention relates to a brake shoe having a lining having a plurality of portions having different material characteristics.

The brake shoe has a lining that generates a braking force by sliding against the inner peripheral surface of the drum brake. The lining is usually formed into a single elongated shape having the same material and the same characteristics. However, a lining having a plurality of portions having different material properties is also known in the art. For example, a lining is known in which both end portions in the longitudinal direction and an intermediate portion therebetween are made of different materials, and the friction coefficient of both end portions is smaller than that of the intermediate portion (see Patent Document 1). This suppresses brake squeal when the brake is operated loosely and ensures the effectiveness of the brake when the brake is operated strongly. Conventionally, there is also known a lining in which both end portions in the short direction of the lining and an intermediate portion therebetween are made of different materials and the friction coefficient of both end portions is smaller than that of the intermediate portion (see Patent Documents 2 and 3). This suppresses brake squeal due to the rigidity of the brake shoe.
JP 2005-291219 A Japanese Patent Laid-Open No. 10-176728 JP-A-10-274264

  However, brake squeal can also occur for other reasons. For example, a drum to which a brake shoe is pressed usually has a disc-shaped disc portion and a cylindrical cylindrical portion standing on the outer periphery of the disc portion, and the disc portion is fixed to one end in the axial direction of the cylindrical portion. is doing. At the time of brake braking, a brake shoe having a lining is pressed against the inner wall of the cylindrical portion to generate a braking force, so that the pressing force of the brake shoe is received by the cylindrical portion of the drum. Therefore, in the cylindrical portion of the drum, the displacement at the time of braking differs between one end portion in the axial direction fixed to the disk portion and the other end portion in the axial direction. Specifically, one end of the cylindrical portion is firmly attached to the disk portion during braking, while the strength is strong, whereas the other end of the cylindrical portion is easily displaced in the diameter increasing direction. It can be estimated that this can cause brake squeal. However, conventionally, there has been no development of a brake shoe that focuses on the shape of the drum or a brake shoe that suppresses brake noise caused by the displacement of the drum. Then, this invention makes it a subject to provide the brake shoe which has a lining which can suppress the brake squeal resulting from the shape of a drum.

  In order to solve the above-mentioned problems, the present invention is a brake shoe for a vehicular drum brake having a configuration as described in each claim. That is, according to the first aspect of the present invention, the cylinder portion and the disk portion fixed to one end in the axial direction of the cylinder portion are pressed against the inner peripheral surface of the cylinder portion of the drum that rotates with the rotation of the wheel. A brake shoe for a vehicular drum brake that generates power, and has a lining that is pressed against the inner peripheral surface of the drum, and the lining has a substantially square shape in which vertex A and vertex C and vertex B and vertex D face each other. Yes, the distance to the vertex A is shorter than the distance to the other vertices B, C, D, and the distance to the vertex B is shorter than the distance to the other vertices A, C, D The distance to an arbitrary point b and the vertex C is shorter than the distance to the other vertices A, B and D, and the distance to the vertex D is the distance to the other vertices A, B and C. If any point d is shorter than the arbitrary point a, b c, the hardness of the lining in d, the most soft hardness at any point a, hardness at the arbitrary point d is that the hardest was.

  By configuring the brake shoe as described above, the strength when the lining of the brake shoe is pressed against the inner peripheral surface of the cylindrical portion of the drum during braking can be adjusted by the hardness of the lining. Therefore, the substantially quadrangular lining is divided into four regions, the hardness at an arbitrary position is adjusted, and the softest arbitrary point a region and the hardest arbitrary point d region are arranged at diagonal positions of the lining. By allowing the lining to be twisted diagonally, it is possible to suppress brake noise and uneven wear of the lining.

According to the invention described in claim 1, it can be suppressed brake squeal the shape of a drum becomes due. At the same time, brake squeaking caused by vibration in the lining in / out direction (longitudinal direction) can also be suppressed. In the former mechanism, the drum is such that the other end side in the axial direction of the cylindrical portion (the side where the disc portion is not fixed) is more radial than the one end side in the axial direction (the side where the disc portion is fixed). Directional displacement increases. On the other hand, in the lining, a region far from the disk portion having a large displacement is softer than a region near the disk portion. Therefore, brake squeal due to the shape of the drum can be suppressed.

  The latter mechanism corresponds to the fact that unstable vibration can occur when the lining hits the drum at two places, the turn-in side and the turn-out side, during braking. For example, when the lining is pressed against the drum at high pressure, such as when the brake is strongly operated, or when the central part of the lining is consumed more than the both ends, the brake shoe will hit the drum in two places, causing unstable vibration of the brake shoe. Can occur. On the other hand, since the lining is harder at the delivery side than at the entry side, the pressure between the lining and the drum is larger at the lining delivery side that serves as a tilting fulcrum during braking. Therefore, unstable vibration of the brake shoe during braking is reduced, and brake noise can be suppressed. Thus, not only brake squeal due to the shape of the drum but also brake squeal due to unstable vibration of the brake shoe in the turning-in / out direction can be suppressed simultaneously.

The above effect can also be obtained in the inventions of the second, third, and fifth aspects.

Furthermore, according to the invention described in claim 4 , when the sliding contact area slidingly contacting the drum of the first to fourth lining bodies is A1 to A4 and the Young's modulus is E1 to E4,
A2≈A3,
0.8 ≦ (E1 × A1) / (E2 × A2) ≦ 1.2,
0.8 ≦ (E4 × A4) / (E2 × A2) ≦ 1.2
It is set to be.

  Therefore, (E1 × A1), (E2 × A2), (E3 × A3), and (E4 × A4) are set to be substantially equal. As a result, the wear amounts of the first to fourth lining bodies are substantially equal, and uneven wear of the lining can be prevented.

  An embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the drum brake 5 includes a disc-shaped backing plate 7 attached to a member on the vehicle body side, a pair of brake shoes 1 movably provided on the backing plate 7, and a wheel attached to the wheel side. It has a drum 6 that rotates with it.

  As shown in FIGS. 1 and 2, the brake shoe 1 integrally includes a crescent-shaped metal web 4 and a metal rim 3 erected on the outer peripheral edge of the web 4. A lining 2 that is a friction material is fixed to the outer peripheral surface of the rim 3. As shown in FIGS. 1 and 3, the central portion of the web 4 is attached to the backing plate 7 so as not to be lifted and movable by the hold down 10. The web 4 has a toe portion 4a that contacts the wheel cylinder 8 at one end, and a heel portion 4b that contacts the anchor 9 at the other end.

  The anchor 9 is a member fixed to a member on the vehicle body side, and protrudes between the heel portions 4b as shown in FIG. 1 to restrict movement of the brake shoe 1 in the circumferential direction. The wheel cylinder 8 has a main body portion 8a that protrudes between the toe portions 4a and is fixed to the vehicle body side, and a pair of pistons 8b that are movably inserted into the main body portion 8a. The piston 8b presses the brake shoe 1 against the drum 6 by pressing the toe part 4a as the hydraulic pressure in the main body part 8a rises in conjunction with the depression of the brake pedal.

  Between the pair of brake shoes 1, return springs 12 and 13 and a strut 11 are provided as shown in FIG. The return springs 12 and 13 are attached between the toe portion 4a and the heel portion 4b. Therefore, the brake shoe 1 moves to a standby position away from the drum 6 by the urging force of the return springs 12 and 13. The strut 11 has a structure in which the entire length is extended when the lining 2 is thinned in order to keep the gap between the brake shoe 1 and the drum 6 constant.

  As shown in FIGS. 2 and 3, the drum 6 integrally includes a disk-shaped disk portion 6a and a cylindrical cylindrical portion 6b. The disk portion 6a is fixed to one end of the cylindrical portion 6b in the axial direction, and has a central hole 6a2 and a plurality of mounting holes 6a1. The center hole 6a2 is formed in the approximate center of the disk part 6a. The plurality of mounting holes 6a1 are formed at substantially constant intervals near the outer periphery of the disk portion 6a. The mounting hole 6a1 is inserted through a stat bolt 15 fixed to the hub 14. A wheel (not shown) is also attached to the stat bolt 15. Accordingly, the drum 6 rotates together with the wheel and the hub 14 when the vehicle travels. As shown in FIGS. 1 and 3, a brake shoe 1 is disposed on the inner peripheral side of the drum 6. The lining 2 of the brake shoe 1 faces the inner peripheral surface 6 b 1 of the cylindrical portion 6 b of the drum 6. The lining 2 is formed of a friction material, and is pressed against the inner peripheral surface 6b1 of the cylindrical portion 6b during braking to generate a braking force by sliding with respect to the inner peripheral surface 6b1.

As shown in FIGS. 2 and 4, the lining 2 has a strip shape and is formed in an arc shape along the rim 3. When deployed, the lining 2 is substantially square and has vertices AD. Vertex A and vertex D, and vertex B and vertex C are located on a diagonal line, respectively. The lining 2 is composed of a plurality of lining bodies 2a to 2d. When the lining bodies 2a to 2d are deployed, each of the lining bodies 2a to 2d has a substantially rectangular shape, and has sliding contact areas A1 to A4 that are in sliding contact with the cylindrical portion 6b. The Young's moduli E1 to E4 and the hardness (HRS) H1 to H4 of the lining bodies 2a to 2d are set so as to satisfy the expressions (1) to (4).
E1 <E2≈E3 <E4 That is, H1 <H2≈H3 <H4 (Formula 1)
A1>A2≈A3> A4 (Expression 2)
0.8 ≦ (E1 × A1) / (E2 × A2) ≦ 1.2 (Formula 3)
0.8 ≦ (E4 × A4) / (E2 × A2) ≦ 1.2 (Formula 4)

Therefore, the first lining body 2a has the smallest Young's modulus and is soft (soft), and therefore forms the soft portion of the lining 2. Since the fourth lining body 2d has the largest Young's modulus and is hard (hard), it constitutes a hard portion of the lining 2. The material properties such as Young's modulus of the lining bodies 2a to 2d are adjusted by making the material components different. Or it is adjusted by making the material component the same and making the press pressure different. The Young's modulus E2 and E3 and the sliding contact areas A2 and A3 are set to be approximately equal, and the difference between them is set to 5% or less, preferably 3% or less. It is preferable that the Young's moduli E1 to E4 are further set to satisfy (Equation 5).
(E2 / E1) ≈ (E4 / E2) = m (Expression 5)
m is 1.1 or more, preferably 1.2 or more, and 2 or less, preferably 1.5 or less.

  As shown in FIGS. 3 and 4, the drum 6 rotates in the direction of arrow R during braking when the vehicle moves forward. At this time, the 1st lining body 2a is located in the area | region of the inflow side of the cylindrical part 6b of the drum 6, and the other side (upper left side of FIG. 4) of the disk part 6a. The 2nd lining body 2b is located in the area | region on the turn-in side and the disk part 6a side (upper right side of FIG. 4). The 3rd lining body 2c is located in the area | region on the extraction side of the cylindrical part 6b, and the other side (lower left side of FIG. 4) of the disk part 6a. The 4th lining body 2d is located in the area | region on the extraction side and the disk part 6a side (lower right side of FIG. 4).

  As shown in FIG. 4, the lining 2 includes a turn-in side edge 2e into which the cylindrical part 6b is turned in, a turn-out side edge 2f to be turned out, a disk part side edge 2h on the disk part 6a side, and a disk part 6a. It has four edges of the opposite disk part opposite edge 2g. The lining 2 is disposed so that the vertex A is an intersection of the turn-in side edge 2e and the disk part opposite side edge 2g. Thereby, the vertex B is located at the intersection of the turn-in side edge 2e and the disk part side edge 2h. The vertex C is located at the intersection of the delivery side edge 2f and the disk part opposite edge 2g, and the vertex D is located at the intersection of the delivery side edge 2f and the disk part side edge 2h.

  As shown in FIG. 4, the boundary 2p1 between the first and second lining bodies 2a and 2b and the boundary 2p2 between the third and fourth lining bodies 2c and 2d are substantially in a straight line. The boundary 2q1 between the first and third lining bodies 2a and 2c and the boundary 2q2 between the second and fourth lining bodies 2b and 2d are also substantially in a straight line. The boundaries 2p1 and 2p2 divide the entrance side edge 2e or the exit side edge 2f at a ratio of 2m1: 2m2. 2m1 corresponds to the short length of the first and third lining bodies 2a and 2c, and 2m2 corresponds to the short length of the second and fourth lining bodies 2b and 2d. The boundaries 2q1 and 2q2 divide the disc portion opposite edge 2g or the disc portion side edge 2h at a ratio of 2n1: 2n2. 2n1 corresponds to the longitudinal length of the first and second lining bodies 2a and 2b, and 2n2 corresponds to the longitudinal length of the third and fourth lining bodies 2c and 2d. 2m1: 2m2 and 2n1: 2n2 are both preferably m: 1 from (Formula 5), and m is 1.1 or more, preferably 1.2 or more and 2 or less, preferably 1.5. Set to:

  The lining 2 has an arbitrary point a where the distance to the vertex A is shorter than the distance to the other vertices B, C, D, and the distance to the vertex B than the distance to the other vertices A, C, D. And any point c where the distance to the vertex C is shorter than the distance to the other vertices A, B, D, and the distance to the vertex D is the other vertex A, B, C. The hardness of the lining 2 at the arbitrary points a to d is the softest at the arbitrary point a and the highest at the arbitrary point d. hard.

  Further, when the lining 2 is divided into four regions by center lines 2j1 and 2j2 that equally divide the longitudinal direction and the transverse direction into two as shown in FIG. 4, the first region 2k1 is a cylinder of the drum 6. It is located on the return side of the part 6b and on the opposite side of the disk part 6a. The second region 2k2 is located on the turn-in side and on the disk portion 6a side, and the third region 2k3 is located on the return side of the cylindrical portion 6b and on the opposite side of the disk portion 6a. 2k4 is located on the delivery side and on the disk portion 6a side. The average Young's modulus of the first to fourth regions 2k1 to 2k4 is set so that the average Young's modulus of the first region 2k1 is the smallest and the average Young's modulus of the fourth region 2k4 is the largest. .

  The brake shoe 1 set to m = 1.2 was created and a brake squeal test was performed. At the same time, a brake squeal test was conducted on a normal brake shoe. As a normal brake shoe, a brake shoe including a lining having the same material characteristics as the second lining body 2b in all regions was prepared. As a test for brake squeal, a drum brake was mounted on the actual vehicle, and the brake squeeze that could occur during braking was measured. As a result, the brake shoe 1 of this embodiment did not generate measurable brake noise, and the normal brake shoe generated brake noise.

  As described above, the hardness of the lining 2 is adjusted in the diagonal region as shown in FIG. Therefore, the strength when the lining 2 of the brake shoe 1 is pressed against the inner peripheral surface 6b1 of the cylindrical portion 6b of the drum 6 during brake braking can be adjusted by the hardness of the lining 2. Therefore, the substantially quadrangular lining 2 is divided into four regions, the hardness at an arbitrary position is adjusted, and the softest arbitrary point a region and the hardest arbitrary point d region are arranged at diagonal positions of the lining. In addition, by allowing the lining 2 to be twisted in the diagonal direction, it is possible to suppress brake noise and uneven wear of the lining 2.

Further, as shown in FIG. 2, the lining 2 has a soft part (2a) in the upper left area (the area on the side where the cylindrical part 6b of the drum 6 is turned in and the side opposite to the disk part 6a), and the lower right part. There is a hard portion (2d) in the region on the side (region on the delivery side of the cylindrical portion 6b and on the disk portion 6a side). Therefore, brake squeal caused by the shape of the drum 6 can be suppressed. At the same time, brake squeal caused by vibration in the turning-in / out direction (longitudinal direction) of the lining 2 can be suppressed. The former mechanism is such that the other end side in the axial direction of the cylindrical portion 6b (the side where the disc portion 6a is not fixed) is more radial than the one end side in the axial direction (the side where the disc portion 6a is fixed). For example, the displacement in the diameter expanding direction increases. On the other hand, in the lining 2, the area far from the disk part 6a having a large displacement is softer than the area close to the disk part 6a. Therefore, brake squeal due to the shape of the drum 6 can be suppressed.

  The latter mechanism corresponds to the fact that unstable vibration may occur when the lining 2 hits the drum 6 at two places, the turn-in side and the turn-out side, during braking. For example, when the lining 2 is pressed against the drum 6 at a high pressure, such as when the brake is strongly operated, or when the central portion of the lining 2 is consumed more than both ends, the brake shoe 1 Unstable vibration can occur. On the other hand, since the lining 2 is harder at the outlet side than the inlet side, the pressure between the lining 2 and the drum 6 becomes larger at the outlet side of the lining 2 that serves as a tilting fulcrum during braking. Therefore, unstable vibration of the brake shoe during braking is reduced, and brake noise can be suppressed. Thus, not only brake squeal due to the shape of the drum 6 but also brake squeal due to unstable vibration of the brake shoe 1 in the turning-in / out direction can be suppressed at the same time.

  In other words, the unstable vibration in the short direction and the unstable vibration in the longitudinal direction of the lining 2 can be suppressed at the same time, thereby effectively suppressing brake noise. Brake noise caused by unstable vibration in the shape of the drum 6 and the lateral direction of the lining 2 is particularly likely to appear in large vehicles. Therefore, the brake shoe 1 of this embodiment is particularly effective for large vehicles.

  Moreover, the 1st-4th lining bodies 2a-2d are set so that it may become Formula (1)-(4). Therefore, (E1 × A1), (E2 × A2), (E3 × A3), and (E4 × A4) are set to be substantially equal. Thereby, the wear amounts of the first to fourth lining bodies 2a to 2d are substantially equal, and uneven wear of the lining 2 can be prevented.

Further, the present invention is not limited to the above embodiment, and may be the following form.
(1) For example, the lining 2 of the above embodiment has a plurality of lining bodies 2 a to 2 d as shown in FIGS. 2 and 4, and these are formed separately. However, a form in which a plurality of lining bodies are integrally formed may be used.
(2) The lining 2 of the above embodiment has four lining bodies 2a to 2d as shown in FIGS. However, it has three or five or more lining bodies, and has a lining body that is a soft part with the smallest Young's modulus in the area on the inflow side of the cylindrical part of the drum and the side opposite to the disk part side of the drum. And the form which has the lining body which is a hard part with the largest Young's modulus in the area | region on the distribution side of a cylindrical part and a disk part side may be sufficient.
(3) The lining bodies 2a to 2d of the above embodiment are all rectangular, but are not limited to this shape, and may be, for example, an elliptical shape.
(4) In the lining 2 of the above embodiment, the upper left region in FIG. 2 (the region on the side where the cylindrical portion 6b is inserted and the side opposite to the disk portion 6a) is the softest, and the lower right region (the rotation of the cylindrical portion 6b) The region on the exit side and the disk portion 6a side) was the hardest configuration. However, the upper right area in FIG. 2 is the softest and the lower left area is the hardest, or the lower left area in FIG. 2 is the softest and the upper right area is the hardest, the lower right area in FIG. 2 is the softest, and the upper left area is the most A hard structure may be sufficient.

It is a front view of the drum brake in the state where the drum was cut along a plane perpendicular to the axial direction. It is a perspective view of a brake shoe and a drum. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1. It is a side view of a brake shoe.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Brake shoe 2 ... Lining 2a ... 1st lining body (soft part)
2b ... 2nd lining body 2c ... 3rd lining body 2d ... 4th lining body (hard part)
2e ... Incoming side edge 2f ... Outlet side edge 2g ... Disc part opposite side edge 2h ... Disc part side edge 2j1, 2j2 ... Center line 2k1-2k4 ... Region 3 ... Rim 4 ... Web 5 ... Drum brake 6 ... Drum 6a ... disk part 6b ... cylindrical part 6b1 ... inner peripheral surface 7 ... backing plate 8 ... wheel cylinder 9 ... anchor

Claims (5)

An inner peripheral surface of the cylindrical portion (6b) of the drum (6) having a cylindrical portion (6b) and a disk portion (6a) fixed to one end in the axial direction of the cylindrical portion (6b) and rotating with the rotation of the wheel. A brake shoe (1) of a vehicle drum brake (5) that is pressed against (6b1) to generate a braking force,
A lining (2) pressed against the inner peripheral surface (6b1) of the drum (6);
The lining (2) has a substantially quadrangular shape in which the vertex A and the vertex D and the vertex B and the vertex C are located on the diagonal lines, respectively.
An arbitrary point a where the distance to the vertex A is shorter than the distance to the other vertices B, C, D, and the distance to the vertex B is greater than the distance to the other vertices A, C, D. An arbitrary point b that becomes shorter, an arbitrary point c whose distance to the vertex C becomes shorter than a distance to the other vertexes A, B, and D, and a distance to the vertex D that becomes the other vertex A, When the arbitrary point d is shorter than the distance to B, C, the lining hardness at the arbitrary point a, b, c, d is the softest at the arbitrary point a, hardness at any point d is rather the most hard,
A wrap-in side edge (2e) of the lining located on the lap-in side of the cylindrical part (6b) at the time of braking when the vehicle moves forward, and a lining of the lining located on the other axial end side of the cylindrical part (6b) A brake shoe (1) of a drum brake (5) for a vehicle , wherein the intersection A formed by the side edge (2g) is the vertex A. An inner circumference of the cylindrical portion (6b) of the drum (6) having a cylindrical portion (6b) and a disk portion (6a) fixed to one end of the cylindrical portion (6b) in the axial direction and rotating with the rotation of the wheel. A brake shoe (1) of a vehicle drum brake (5) that is pressed against a surface (6b1) to generate a braking force,
A lining (2) pressed against the inner peripheral surface (6b1) of the drum (6);
The lining (2) is provided on the side of the cylindrical portion (6b) of the drum (6) at the time of braking when the vehicle moves forward and on the side opposite to the disk portion (6a) side of the drum (6) . One region, a second region on the entry side and on the disk portion (6a) side, a third region on the return side of the cylindrical portion (6b) and on the opposite side of the disk portion (6a), A fourth region on the outlet side and on the disk portion (6a) side;
The first region has a soft portion (2a) having a Young's modulus smaller than that of the second region, the third region, and the fourth region , and is provided on the outlet side of the cylindrical portion (6b) and the disc portion ( The brake of the vehicle drum brake (5), wherein the fourth region on the side 6a) has a hard portion (2d) having a Young's modulus larger than that of the first region, the second region, and the third region. Shoe (1). An inner circumference of the cylindrical portion (6b) of the drum (6) having a cylindrical portion (6b) and a disk portion (6a) fixed to one end of the cylindrical portion (6b) in the axial direction and rotating with the rotation of the wheel. A brake shoe (1) of a vehicle drum brake (5) that is pressed against a surface (6b1) to generate a braking force,
A lining (2) pressed against the inner peripheral surface (6b1) of the drum (6);
The lining (2) is disposed on the side of the cylindrical portion (6b) of the drum (6) during braking when the vehicle moves forward and on the opposite side of the disk portion (6a) of the drum (6). The first lining body (2a) to be formed, the second lining body (2b) disposed on the circulation side and the disk part (6a) side, and the delivery side of the cylindrical part (6b) And a third lining body (2c) disposed on the opposite side of the disk portion (6a), and a fourth lining body (2) disposed on the delivery side and on the disk portion (6a) side. 2d)
When the Young's modulus of the first to fourth lining bodies (2a to 2d) is E1 to E4,
E1 <E2≈E3 <E4
The brake shoe (1) of the drum brake (5) for vehicles characterized by setting so that it may become. A brake shoe (1) for a vehicle drum brake (5) according to claim 3 ,
When the sliding contact area of the first to fourth lining bodies (2a to 2d) slidably contacting the drum (6) is A1 to A4 and Young's modulus is E1 to E4,
A2≈A3,
0.8 ≦ (E1 × A1) / (E2 × A2) ≦ 1.2,
0.8 ≦ (E4 × A4) / (E2 × A2) ≦ 1.2
The brake shoe (1) of the drum brake (5) for vehicles characterized by setting so that it may become. An inner circumference of the cylindrical portion (6b) of the drum (6) having a cylindrical portion (6b) and a disk portion (6a) fixed to one end of the cylindrical portion (6b) in the axial direction and rotating with the rotation of the wheel. A brake shoe (1) of a vehicle drum brake (5) that is pressed against a surface (6b1) to generate a braking force,
A lining (2) pressed against the inner peripheral surface (6b1) of the drum (6);
When the lining (2) is divided into four regions, each of which is divided into two in the longitudinal direction and the short direction, the four regions are the cylindrical portions (6) of the drum (6) during braking when the vehicle moves forward. A first region (2k1) on the inflow side of 6b) and on the opposite side of the disc portion (6a) side of the drum (6), and a second region on the ingress side and on the disc portion (6a) side. Area (2k2), a third area (2k3) on the delivery side of the cylindrical part (6b) and on the opposite side to the disk part (6a) side, and the delivery part and the disk part (6a) ) Side fourth region (2k4)
The average Young's modulus of each of the first to fourth regions (2k1 to 2k4) has the smallest average Young's modulus of the first region (2k1), and the average Young's modulus of the fourth region (2k4) is the smallest. A brake shoe (1) for a vehicle drum brake (5), which is set to be large.

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