Brake shoes and brake control devices

Abstract

This prevents grooving and paint peeling on the non-flange side, and shortens the time it takes for the wheel tread and brake shoe tread to make 100% contact. [Solution] The brake shoe has a plurality of contact portions 11A and 11B with different gradients in the vehicle width direction on the brake shoe tread 11 that contacts the wheel tread 22 of the wheel 20A. Of the plurality of contact portions 11A and 11B, at least the flange-side contact portion 11A located on the flange side of the wheel 20A in the vehicle width direction contacts the wheel 20A.

Description

Technical Field

[0001] The present invention relates to a wheel brake and a brake control device.

Background Art

[0002] Conventionally, a vehicle wheel brake for braking a wheel by pressing against the tread of the vehicle wheel is known (see, for example, Patent Document 1). In such a wheel brake, it takes, for example, several months for the wheel brake tread to contact the wheel tread 100%.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above conventional wheel brake, when the contact rate of the wheel brake tread with respect to the wheel tread is less than 100%, water enters between the wheel tread and the wheel brake tread, the friction coefficient decreases, and the braking performance deteriorates. Therefore, although the same gradient as that of the wheel is provided on the wheel brake side, when the wheel brake gradient becomes larger than the wheel gradient due to product variations, local heat generation occurs on the anti-flange side, and a phenomenon (grooving) in which thin grooves are formed on the wheel tread on the anti-flange side occurs. In order to avoid such grooving on the anti-flange side, by making the magnitude of the wheel brake gradient smaller than that of the wheel, local heat generation may be caused on the flange side having a large heat capacity. However, there is a problem that although the degree of grooving is reduced, it is not a reliable countermeasure.

[0005] The flange side of the wheel has a flange thickness in the vehicle width direction. The distance from the flange side of the wheel to the brake shoe contact end is greater in the vehicle width direction than the distance from the non-flange side end to the brake shoe contact end. In other words, in the wheel, the volume of the non-flange side from the non-flange side end to the brake shoe contact end is smaller in the vehicle width direction compared to the flange side from the flange side end to the brake shoe contact end, and therefore the heat capacity is also smaller. Repeated heating and cooling due to uneven contact of the brake shoe tread on the non-flange side of the wheel can cause the paint on the non-flange side end face of the wheel to peel off. Therefore, rather than accepting product variations, it is necessary to ensure that the flange side of the brake shoe tread makes reliable local contact with the wheel tread.

[0006] Furthermore, when the gradient of the brake shoe is made smaller than the gradient of the wheel, it takes, for example, more than three months longer than with a standard product for the brake shoe tread to make 100% contact with the wheel tread. Therefore, there is a problem in that sufficient braking performance cannot be maintained for a long period of time, and there was room for improvement in that respect.

[0007] The present invention provides a brake shoe and a brake control device that can prevent grooving and paint peeling on the non-flange side, and shorten the time until the wheel tread and the brake shoe tread are in 100% contact. [Means for solving the problem]

[0008] A brake shoe according to one aspect of the present invention has a plurality of contact portions of the brake shoe tread that contact the wheel tread of the wheel, each having a different gradient in the vehicle width direction, and of the plurality of contact portions, at least the contact portion located on the flange side of the wheel in the vehicle width direction contacts the wheel.

[0009] This configuration provides multiple contact points with different gradients on the brake shoe tread. By ensuring that at least the contact points located on the flange side of the wheel in the vehicle width direction make contact with the wheel, the initial contact between the brake shoe tread and the standard wheel tread is reliably on the flange side. In other words, the brake shoe tread contacts the wheel tread from the flange side. This avoids uneven contact on the non-flange side, which has a smaller heat capacity, and prevents grooving and paint peeling on the non-flange side of the wheel. Furthermore, in this case, it becomes unnecessary to make the gradient of the wheel tread greater than the gradient of the brake shoe, thus shortening the time it takes for 100% contact to be made with the wheel tread.

[0010] It is desirable that the gradient of the contact portion on the flange side is greater than the gradient of the other contact portions.

[0011] With this configuration, the brake shoe tread contacts the wheel tread from the flange side, which has a steeper gradient. This avoids uneven contact on the non-flange side, which has a smaller heat capacity, thus preventing grooving and paint peeling on the non-flange side of the wheel. Furthermore, in this case, on the brake shoe tread, the gradient of the contact points on the non-flange side is smaller and gentler than the gradient of the contact point on the flange side, thus shortening the time required to achieve 100% contact with the wheel tread.

[0012] It is desirable that the ratio of the contact portion on the flange side to the vehicle width in the vehicle width direction be 50 to 95%.

[0013] This configuration ensures a non-contact distance between the brake shoe tread and the wheel tread on the non-flange side, which has a smaller heat capacity, thus more reliably preventing grooving and paint peeling on the non-flange side of the wheel.

[0014] It is desirable that the gradient of the contact portion on the side opposite the flange among the multiple contact portions is greater than the gradient of the other contact portions.

[0015] By configuring it in this way, the gradients of the multiple contact points on the brake shoe tread and the gradients of each contact point on the wheel tread are made the same, allowing the brake shoe tread to reliably make contact with the wheel tread over its entire surface from the beginning, thereby increasing the contact area.

[0016] It is desirable that the length of the contact portion on the flange side in the vehicle width direction is longer than the length of the contact portion on the flange side of the wheel tread in the vehicle width direction.

[0017] With this configuration, the point of gradient change between the contact point on the flange side of the brake shoe tread and the contact point adjacent to the non-flange side of the flange-side contact point is located on the non-flange side of the gradient change point between the flange-side contact point and the non-flange-side contact point on the wheel tread. This ensures that the initial contact between the brake shoe tread and the wheel tread is always on the flange side. In other words, the brake shoe tread contacts the wheel tread from the flange side. Therefore, uneven contact on the non-flange side, which has a smaller heat capacity, can be avoided, preventing grooving and paint peeling on the non-flange side of the wheel.

[0018] It is desirable that the gradient of the plurality of contact points is the same as the gradient of the wheel with which these plurality of contact points make contact.

[0019] By configuring it in this way, the gradients of the multiple contact points on the brake shoe tread and the gradients of each contact point on the wheel tread are made the same, allowing the brake shoe tread to reliably make contact with the wheel tread over its entire length from the beginning, thereby increasing the contact area. In other words, the brake shoe tread and the wheel tread make reliably contact from the beginning, even on the flange side.

[0020] It is desirable that there be two contact portions with different gradients.

[0021] This configuration makes it easier to manufacture brake shoes compared to, for example, brake shoe treads with three or more contact points.

[0022] It is desirable that the material be made of a friction modifier containing a synthetic resin as a main component and at least one of carbon powder and iron powder as an additive.

[0023] By forming a skid with such a material, the contact area with the wheel tread can be improved. Therefore, the time until 100% contact with the wheel tread can be shortened.

[0024] A brake control device according to another aspect of the present invention is a brake control device using the above-described skid, and includes an electric motor provided in a vehicle, a drive control unit that drives the electric motor according to a brake command received from an external device, and a control unit that controls braking of the vehicle by pressing and contacting the contact portion of the skid against the wheel tread of the wheel by driving the electric motor.

[0025] By configuring in this way, by mounting the skid that can obtain the above-described effects, it becomes possible to control the braking of the vehicle by the control unit by pressing and contacting the contact portion of the skid against the wheel tread of the wheel by driving the electric motor, and it is possible to prevent grooving and peeling of the paint on the anti-flange side, and a brake control device that can shorten the time until 100% contact between the wheel tread and the skid tread can be provided.

Advantages of the Invention

[0026] The above-described skid and brake control device can prevent grooving and peeling of the paint on the anti-flange side, and can shorten the time until 100% contact between the wheel tread and the skid tread.

Brief Description of the Drawings

[0027] [Figure 1] Side view of the wheel and skid of the first embodiment. [Figure 2] Side view of the skid shown in FIG. 1. [Figure 3] Side view of the wheel and skid of the second embodiment. [Figure 4] Side view of the wheel and skid of the third embodiment. [Figure 5] A side view illustrating the operation of the wheel and brake shoe shown in Figure 4. [Figure 6A] A side view of the wheel and brake shoe of the fourth embodiment, showing the view before contact. [Figure 6B] Figure 6A is a side view of the wheel and brake shoe, showing the situation after contact. [Figure 7A] A side view of the wheel and brake shoe of the fifth embodiment, showing the view before contact. [Figure 7B] Figure 7A is a side view of the wheel and brake shoe, showing the situation after contact. [Modes for carrying out the invention]

[0028] <First Embodiment> Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, brake shoes for four-wheeled automobiles will be used as examples. In the following description, expressions indicating relative or absolute arrangements such as "parallel," "orthogonal," "center," and "coaxial" will not only mean such arrangements strictly, but will also include states in which the components are relatively displaced by an angle or distance that allows for tolerances or the same function to be obtained. In the drawings used in the following description, the scale of each component has been appropriately changed in order to make each component recognizable.

[0029] <Bracelets> Figure 1 is a side view of the brake shoe 1A of the first embodiment. Figure 2 is a side view of the brake shoe 1A shown in Figure 1. As shown in Figures 1 and 2, the brake shoe 1A has multiple contact portions 11A and 11B with different gradients in the vehicle width direction of the brake shoe tread 11 that contact the wheel tread 22 of the wheel 20A, and the vehicle is braked by bringing the brake shoe tread 11 into contact with the wheel tread 22 of the wheel 20A.

[0030] In the following explanation, the Cartesian coordinate system of X, Y, and Z will be used as needed. For example, when a vehicle brake shoe 1 is mounted on a vehicle, the X, Y, and Z directions have the following relationships with respect to each direction of the vehicle: The X direction coincides with the vehicle's longitudinal direction. The Y direction coincides with the vehicle's width direction. The Z direction coincides with the vehicle's height direction (gravity direction), which is perpendicular to the X and Y directions. In the following explanation, the side of the Y and Z directions indicated by the arrows in the diagram will be considered the positive (+) side, and the side opposite the arrows will be considered the negative (-) side. The +Z side corresponds to the upper side in the direction of gravity, and the -Z side corresponds to the lower side in the direction of gravity.

[0031] The vehicle's wheel 20A has an arc-shaped wheel tread 22. The wheel 20A has a flange 21 that protrudes outward in the vehicle radial direction from the entire circumference of the peripheral edge on one end (+Y side) in the width direction (Y direction). The wheel 20A does not have a flange on the peripheral edge on the side opposite to the flange 21 side in the width direction (Y direction) (hereinafter referred to as the anti-flange side (-Y side)).

[0032] The wheel tread 22 of the wheel 20A is the contact surface against which at least a portion of the brake shoe tread 11 of the brake shoe 1A (described later) is pressed. The wheel tread 22 has a first contact portion 22A formed thereon, which has a gradient that gradually decreases in diameter from the flange side end to the non-flange side end. The first contact portion 22A has a constant gradient over the entire width direction of the vehicle. For example, the gradient of the first contact portion 22A is 1 / 15 to 1 / 25. The product tolerance of the wheel tread 22 is ±25%, for example, if the gradient of the first contact portion 22A is 1 / 20. Note that if the gradient is 1 / 15, for example, the horizontal distance is 15 mm and the height relative to the horizontal distance is 1 mm.

[0033] The brake shoe 1A has a roughly arc shape that conforms to the wheel tread 22. The brake shoe 1A generates braking force through friction when the brake shoe tread 11 is pressed against the wheel tread 22. For example, the material of the brake shoe 1A is made of a synthetic resin material containing metal and rubber. For example, the brake shoe 1A is formed mainly of synthetic resin, with friction modifiers such as carbon powder and iron powder mixed in as additives. The material used to form the brake shoe 1A can be changed according to the design specifications.

[0034] The brake shoe tread 11 has multiple (two in this embodiment) contact portions 11A and 11B with different gradients. The brake shoe tread 11 has a flange-side contact portion 11A located on the flange side (+Y side) of the gradient change point 11a, and a non-flange-side contact portion 11B located on the opposite side (-Y side) of the gradient change point 11a. The flange-side contact portion 11A is set to have a steeper gradient than the non-flange-side contact portion 11B. The flange-side contact portion 11A has the same gradient as the first contact portion 22A of the wheel tread 22. The non-flange-side contact portion 11B has a gentler gradient than the flange-side contact portion 11A. Therefore, the non-flange-side contact portion 11B may include, for example, a gradient of 0 or a negative gradient.

[0035] The length L1 of the flange-side contact portion 11A in the vehicle width direction (Y direction) is 50-95% of the vehicle width dimension L of the brake shoe 1A in the vehicle width direction. For example, the length L1 of the flange-side contact portion 11A in the vehicle width direction is set to 75% of the vehicle width dimension L, and the length L2 of the non-flange-side contact portion 11B in the vehicle width direction is set to 25% of the vehicle width dimension L. That is, for example, if the vehicle width dimension L is 80 mm, the length L1 of the flange-side contact portion 11A can be set to 60 mm, and the length L2 of the non-flange-side contact portion 11B can be set to 20 mm. It is preferable that the length L2 of the non-flange-side contact portion 11B be 5 mm or more.

[0036] The flange-side contact portion 11A contacts the flange-side (+Y side) portion of the first contact portion 22A of the wheel tread 22. The non-flange-side contact portion 11B does not contact the non-flange-side (-Y side) portion of the first contact portion 22A of the wheel tread 22.

[0037] The brake shoe 1A described above can be provided, for example, in a brake control device (not shown). That is, the brake control device includes an electric motor provided on the vehicle, a drive control unit that drives the electric motor according to a brake command received from an external device, and a control unit that controls the braking of the vehicle by pressing the contact portions 11A and 11B of the brake shoe 1A against the wheel tread 22 of the wheel 20A using the drive of the electric motor.

[0038] <Effects and Effects> As described above, the brake shoe 1A according to this first embodiment has a plurality of contact portions 11A and 11B of the brake shoe tread 11 that contact the wheel tread 22 of the wheel 20A, each having a different gradient in the vehicle width direction. Of the plurality of contact portions 11A and 11B, at least the flange-side contact portion 11A located on the flange side of the wheel 20A in the vehicle width direction contacts the wheel 20A.

[0039] In this configuration, the brake shoe tread 11 is provided with multiple contact portions 11A and 11B with different gradients. By ensuring that at least the flange-side contact portion 11A of the wheel 20A contacts the wheel in the vehicle width direction, the initial contact between the brake shoe tread 11 and the standard wheel tread 22 is reliably on the flange side. In other words, the brake shoe tread 11 contacts the wheel tread 22 from the flange side. This avoids uneven contact on the non-flange side, which has a smaller heat capacity, and prevents grooving and peeling of the paint on the non-flange side of the wheel 20A. Furthermore, in this case, it becomes unnecessary to make the gradient of the wheel tread 22 greater than the gradient of the brake shoe 1A, thus shortening the time until 100% contact is achieved with the wheel tread 22.

[0040] In the brake shoe 1A according to this embodiment, it is desirable that the gradient of the flange-side contact portion 11A is greater than the gradient of the other contact portion (the non-flange-side contact portion 11B). With this configuration, the brake shoe tread 11 contacts the wheel tread 22 from the flange-side contact portion 11A, which has a steeper gradient. This avoids uneven contact on the non-flange side, which has a smaller heat capacity, and prevents grooving and peeling of the paint on the non-flange side of the wheel 20A. Furthermore, in this case, on the brake shoe tread 11, the gradient of the contact portion 11B on the non-flange side is smaller and gentler than the gradient of the contact portion 11A on the flange side, so the time until 100% contact with the wheel tread 22 can be shortened.

[0041] In the brake shoe 1A according to this embodiment, the ratio of the flange-side contact portion 11A to the vehicle width in the vehicle width direction is 50 to 95%. This configuration ensures a non-contact distance between the brake shoe tread 11 and the wheel tread 22 on the non-flange side, which has a smaller heat capacity, thereby more reliably preventing grooving and peeling of the paint on the non-flange side of the wheel.

[0042] In the brake shoe 1A according to this embodiment, there are two contact portions 11A and 11B with different gradients, so the brake shoe can be manufactured more easily compared to, for example, a brake shoe tread having three or more contact portions.

[0043] The brake shoe 1A according to this embodiment is made of a material consisting of a friction modifier mainly composed of synthetic resin and containing at least one of carbon powder and iron powder as an additive. By forming the brake shoe 1A with such a material, the contact area with the wheel tread 22 can be improved. Therefore, the time required to achieve 100% contact with the wheel tread 22 can be shortened.

[0044] In the brake control device according to this embodiment, by mounting the brake shoe 1A which provides the above-described effects, the control unit can control the braking of the vehicle by pressing the contact portions 11A and 11B of the brake shoe 1A against the wheel tread 22 of the wheel 20A using the drive of the electric motor. This prevents grooving and paint peeling on the non-flange side, and shortens the time until the wheel tread 22 and the brake shoe tread 11 make 100% contact.

[0045] It should be noted that the technical scope of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention.

[0046] <Second Embodiment> As shown in Figure 3, the brake shoe 1B according to the second embodiment has contact portions 12A and 12B with different gradients, and brakes the vehicle by bringing the brake shoe tread 12 into contact with the wheel tread 23 of the wheel 20B.

[0047] The wheel tread 23 has a first contact portion 23A and a second contact portion 23B, which have a gradient that gradually decreases in diameter from the flange-side end to the non-flange-side end. The second contact portion 23B has a steeper gradient than the first contact portion 23A. The first contact portion 23A is located on the flange side (+Y side) of the gradient change point 23a, which is the intersection with the second contact portion 23B. The second contact portion 23B is located on the non-flange side (-Y side) of the gradient change point 23a.

[0048] Brake shoe 1B has a roughly arc shape that follows the wheel tread 23. Brake shoe 1B generates braking force by friction when the brake shoe tread 12 is pressed against the wheel tread 23. For example, the material of brake shoe 1B is the same as the material of brake shoe 1A in the first embodiment described above.

[0049] The brake shoe tread 12 has multiple contact portions 12A and 12B with different gradients. The brake shoe tread 12 has a flange-side contact portion 12A located on the flange side (+Y side) of the gradient change point 12a, and a non-flange-side contact portion 12B located on the opposite side (-Y side) of the gradient change point 12a. The flange-side contact portion 12A is set to have a smaller gradient than the non-flange-side contact portion 12B. The flange-side contact portion 12A has the same gradient as the first contact portion 23A of the wheel tread 23. The non-flange-side contact portion 12B has a larger (steeper) gradient than the flange-side contact portion 12A. The non-flange-side contact portion 12B has the same gradient as the second contact portion 23B of the wheel tread 23.

[0050] The length L1 of the flange-side contact portion 12A in the vehicle width direction (Y direction) is 50-95% of the vehicle width dimension L of the brake shoe 1B in the vehicle width direction. For example, the length L1 of the flange-side contact portion 12A in the vehicle width direction is set to 75% of the vehicle width dimension L, and the length L2 of the non-flange-side contact portion 12B in the vehicle width direction is set to 25% of the vehicle width dimension L. That is, for example, if the vehicle width dimension L is 80 mm, the length L1 of the flange-side contact portion 12A can be set to 60 mm, and the length L2 of the non-flange-side contact portion 12B can be set to 20 mm. It is preferable that the length L2 of the non-flange-side contact portion 12B be 5 mm or more.

[0051] The flange-side contact portion 12A and the non-flange-side contact portion 12B contact the first contact portion 23A and the second contact portion 23B of the wheel tread 22, respectively.

[0052] According to the brake shoe 1B of the second embodiment, the gradient of the contact portion 12B on the non-flange side of the multiple contact portions 12A, 12B is greater than the gradient of the other flange-side contact portions 12A. Furthermore, according to the brake shoe 1B of the second embodiment, the gradients of the multiple contact portions 12A, 12B are the same as the gradient of the wheel 20B that these multiple contact portions 12A, 12B contact. With this configuration, by making the gradients of the multiple contact points 12A and 12B of the brake shoe tread 12 the same as the gradients of the contact points 23A and 23B of the wheel tread 23, the brake shoe tread 12 can reliably make initial contact with the wheel tread 23 over its entire length, thereby increasing the contact area. In other words, the brake shoe tread 12 and the wheel tread 23 can reliably make initial contact even on the flange side.

[0053] <Third Embodiment> As shown in Figure 4, the brake shoe 1C according to the third embodiment has contact portions 13A and 13B with different gradients, and brakes the vehicle by bringing the brake shoe tread surface 13 into contact with the wheel tread surface 24 of the wheel 20C.

[0054] The wheel tread surface 24 has a gradient in which a first contact portion 24A and a second contact portion 24B are formed, with the diameter gradually decreasing from the flange-side end to the non-flange-side end. The second contact portion 24B has a steeper gradient than the first contact portion 24A. The first contact portion 24A is located on the flange side (+Y side) of the gradient change point 24a, which is the intersection with the first contact portion 24B. The second contact portion 24B is located on the non-flange side (-Y side) of the gradient change point 24a.

[0055] The brake shoe 1C has a roughly arc shape that follows the wheel tread 24. The brake shoe 1C generates braking force due to friction when the brake shoe tread 13 is pressed against the wheel tread 24. For example, the material of the brake shoe 1C is the same as the material of the brake shoe 1A in the first embodiment described above.

[0056] The brake shoe tread 13 has multiple contact portions 13A and 13B with different gradients. The brake shoe tread 13 has a flange-side contact portion 13A located on the flange side (+Y side) of the gradient change point 13a, and a non-flange-side contact portion 13B located on the opposite flange side (-Y side) of the gradient change point 13a. The flange-side contact portion 13A is set to have a smaller gradient than the non-flange-side contact portion 13B. That is, the flange-side contact portion 13A is set to have a smaller gradient than the non-flange-side contact portion 13B, which has the largest gradient among the contact portions located on the opposite flange side (-Y side) of the flange-side contact portion 13A. The flange-side contact portion 13A has the same gradient as the first contact portion 24A of the wheel tread 24. The non-flange-side contact portion 13B has a larger (steeper) gradient than the flange-side contact portion 13A. The non-flange-side contact portion 13B has the same gradient as the second contact portion 24B of the wheel tread 24.

[0057] In the brake shoe 1C of the third embodiment, when the brake shoe tread 13 contacts the wheel tread 24, the point of gradient change 13a on the brake shoe side between the flange-side contact portion 13A and the non-flange-side contact portion 13B is located on the non-flange side (-Y side) than the point of gradient change 24a on the wheel side between the first contact portion 24A and the second contact portion 24B of the wheel tread 24. That is, the width dimension B of the second contact portion 24B, which is located on the non-flange side (-Y side) than the gradient change point 24a of the wheel tread 24, is wider than the width dimension A of the non-flange-side contact portion 13B, which is on the flange side (+Y side) than the gradient change point 13a of the brake shoe 1C. In this case, a part of the flange-side contact portion 13A on the flange side (+Y side) contacts the first contact portion 24A, while the other part of the flange-side contact portion 13A on the non-flange side (-Y side) and the non-flange-side contact portion 13B do not contact the wheel tread 24.

[0058] In contrast, in the comparative example brake shoe 1C shown in Figure 5, when the brake shoe tread 13 contacts the wheel tread 24, the gradient change point 13a on the brake shoe side is located on the flange side (+Y side) than the gradient change point 24a on the wheel side. That is, the width dimension B of the second contact portion 24B, which is located on the opposite flange side (-Y side) from the gradient change point 24a of the wheel tread 24, is narrower than the width dimension A of the opposite flange side contact portion 13B of the brake shoe 1C, which is on the opposite flange side (-Y side) from the gradient change point 13a. In this case, the flange side contact portion 13A does not contact the first contact portion 24A, and the opposite flange side contact portion 13B contacts the second contact portion 24B, i.e., the wheel tread 24, first, which is unsuitable.

[0059] According to the brake shoe 1C of the third embodiment, the length of the flange-side contact portion 13A in the vehicle width direction is longer than the length of the first contact portion 24A on the flange side of the wheel tread 24 in the vehicle width direction.

[0060] With this configuration, the gradient change point 13a between the flange-side contact portion 13A and the non-flange-side contact portion 13B adjacent to the non-flange side of the flange-side contact portion 13A on the brake shoe tread 13 is located on the non-flange side than the gradient change point 24a between the first contact portion 24A on the flange side and the second contact portion 24B on the non-flange side on the wheel tread 24. This ensures that the initial contact between the brake shoe tread 13 and the wheel tread 24 is reliably on the flange side. In other words, the brake shoe tread 13 contacts the wheel tread 24 from the flange side. Therefore, uneven contact on the non-flange side, which has a smaller heat capacity, can be avoided, and grooving and peeling of the paint on the non-flange side of the wheel 20C can be prevented.

[0061] Furthermore, according to the third embodiment of the brake shoe 1C, since the brake shoe tread surface 13 has two contact portions 13A and 13B, it is easier to manufacture compared to, for example, a case where there are three or more contact portions.

[0062] <Fourth Embodiment> As shown in Figures 6A and 6B, the brake shoe 1D according to the fourth embodiment has a brake shoe tread 14 with three different gradient contact portions. The brake shoe tread 14 of the brake shoe 1D has a flange-side contact portion 14A, a non-flange-side contact portion 14B, and a central contact portion 14C. The gradient of the flange-side contact portion 14A is approximately the same as the gradient of the first contact portion 25A on the flange side of the wheel tread 25 of the wheel 20D. The gradient of the non-flange-side contact portion 14B is approximately the same as the gradient of the second contact portion 25B on the non-flange side of the wheel tread 25 of the wheel 20D, and is greater than the gradient of the flange-side contact portion 14A. The central contact portion 14C is located between the flange-side contact portion 14A and the non-flange-side contact portion 14B. The central contact portion 14C is approximately horizontal (gradient 0).

[0063] The intersection point of the gradient of the flange-side contact portion 14A and the gradient of the central contact portion 14C (the gradient change point 14a on the brake shoe side) is located on the opposite side of the flange (-Y side) from the intersection point of the gradient of the first contact portion 25A and the gradient of the second contact portion 25B of the wheel 20D (the gradient change point 25a on the wheel side). As shown in Figure 6B, in the fourth embodiment, the brake shoe 1D ensures that the flange-side contact portion 14A makes secure contact with the first contact portion 25A when the brake shoe tread surface 14 is in contact with the wheel tread surface 25.

[0064] In the brake shoe 1D of the fourth embodiment, the amount of gap between the anti-flange side contact portion 14B and the second contact portion 25B is easy to control.

[0065] <Fifth Embodiment> As shown in Figures 7A and 7B, the brake shoe 1E according to the fifth embodiment has a brake shoe tread 15 with three different gradient contact portions. The brake shoe tread 15 of the brake shoe 1D has a flange-side contact portion 15A, a non-flange-side contact portion 15B, and a central contact portion 15C. The gradient of the flange-side contact portion 15A is approximately the same as the gradient of the first contact portion 26A on the flange side of the wheel tread 26 of the wheel 20E. The non-flange-side contact portion 15B is approximately horizontal (gradient 0). The central contact portion 14C is located between the flange-side contact portion 15A and the non-flange-side contact portion 15B. The gradient of the central contact portion 15C is approximately the same as the gradient of the second contact portion 26B on the non-flange side of the wheel tread 26 of the wheel 20E, and is greater than the gradient of the flange-side contact portion 15A.

[0066] The intersection point of the gradient of the flange-side contact portion 15A and the gradient of the central contact portion 15C (the gradient change point 15a on the brake shoe side) is located on the opposite side of the flange (-Y side) from the intersection point of the gradient of the first contact portion 26A and the gradient of the second contact portion 26B of the wheel 20E (the gradient change point 26a on the wheel side). As shown in Figure 7B, in the fifth embodiment, the brake shoe 1E ensures that the flange-side contact portion 15A makes secure contact with the first contact portion 26A when the brake shoe tread surface 15 is in contact with the wheel tread surface 26.

[0067] In the brake shoe 1E of the fifth embodiment, it is easier to control the amount of gap in the non-contact area between the anti-flange side contact portion 15B and the second contact portion 26B.

[0068] It should be noted that the present invention is not limited to the embodiments described above, and various design modifications are possible without departing from the spirit of the invention. For example, the present invention may be applied to vehicles other than four-wheeled automobiles. For example, the present invention may be applied to railway vehicles, bicycles, motorcycles, construction vehicles, industrial vehicles, and the like.

[0069] Furthermore, it is possible to replace the components in the above-described embodiments with well-known components without departing from the spirit of the present invention. Also, the above-described modifications may be combined. Among the embodiments disclosed herein, those composed of multiple objects may be integrated, and conversely, those composed of a single object may be divided into multiple objects. Whether or not they are integrated, the invention can be constructed in a way that achieves its objective. [Explanation of symbols]

[0070] 1A, 1B, 1C, 1D, 1E... Brake shoe, 11, 12, 13, 14, 15... Brake shoe tread, 11A, 12A, 13A, 14A, 15A... Fran Contact area on the flange side, 11B, 12B, 13B, 14B, 15B... Contact area on the anti-flange side, 11a, 12a, 13a, 14a, 15a... Change in slope of brake shoe Point, 20A, 20B, 20C, 20D, 20E...Wheel, 21...Flange, 22, 23, 24, 25, 26...Wheel tread, 22A, 23A, 2 4A, 25A, 26A...First contact part, 23B, 24B, 25B, 26B...Second contact part, 23a, 24a, 25a, 26a...Wheel slope change point

Claims

1. The brake shoe tread has multiple contact points with different gradients in the vehicle width direction, which contact the wheel tread. A brake shoe in which, of the plurality of contact portions, at least the contact portion located on the flange side of the wheel in the vehicle width direction contacts the wheel.

2. The brake shoe according to claim 1, wherein the gradient of the contact portion on the flange side is greater than the gradient of the other contact portions.

3. The brake shoe according to claim 2, wherein the ratio of the contact portion on the flange side to the vehicle width in the vehicle width direction is 50 to 95%.

4. The brake shoe according to claim 1, wherein the gradient of the contact portion on the side opposite the flange among the plurality of contact portions is greater than the gradient of the other contact portions.

5. The brake shoe according to claim 4, wherein the length of the contact portion on the flange side in the vehicle width direction is longer than the length of the contact portion on the flange side of the wheel tread in the vehicle width direction.

6. The brake shoe according to claim 4, wherein the gradient of the plurality of contact portions is the same as the gradient of the wheel in contact with the plurality of contact portions.

7. The brake shoe according to claim 1, wherein there are two contact portions with different gradients.

8. The brake shoe according to claim 1, wherein the material is made of a friction modifier mainly composed of synthetic resin and containing at least one of carbon powder and iron powder as an additive.

9. A brake control device using a brake shoe according to any one of claims 1 to 8, The electric motor installed in the vehicle, A drive control unit that drives the electric motor according to a brake command received from an external device, A brake control device comprising: a control unit that controls the braking of the vehicle by pressing the contact portion of the brake shoe against the wheel tread of the wheel using the drive of the electric motor; and a control unit that controls the braking of the vehicle by the electric motor.

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