Brake device

Abstract

A brake device 1 comprises: a belt-like band member 10 that surrounds an outer peripheral surface of a shaft member 2 rotating around an axis Ax and fastens the shaft member 2 by being deformed; a drive device 20 that is disposed on the band member 10 and executes driving so as to cause deformation of the band member 10; a first contact part 31 that comes into contact with a first end part 10a of the band member 10 to stop rotation of the band member 10 when the band member 10 rotates in a first direction D1 around the axis Ax; and a second contact part 32 that comes into contact with a second end part 10b of the band member 10 to stop rotation of the band member 10 when the band member 10 rotates around the axis Ax in a second direction D2 opposite the first direction D1.

Description

Brake system

[0001] The present disclosure relates to braking systems.

[0002] Patent Document 1 discloses, as an example of a brake device, a brake band device that prevents the brake band from tilting and the lining from coming into contact with the brake drum when the brakes are not applied. The brake device in Patent Document 1 includes a brake band, an apply bracket disposed at a first end of the brake band, and an anchor bracket disposed at a second end of the brake band. The anchor bracket is fixed to a case.

[0003] In the brake device of Patent Document 1, the pressing member presses the apply bracket, causing the brake band to deform and tighten the brake drum, thereby applying the brake pressure to the brake drum.

[0004] Japanese Patent Application Laid-Open No. 2007-107597

[0005] In the brake device of Patent Document 1, when the brake drum rotates in the direction in which the apply bracket is pressed, the brake drum rotates in the direction in which the brake band wraps around itself, which means that the braking force of the brake device increases.

[0006] On the other hand, if the direction in which the apply bracket is pressed is opposite to the direction in which the brake drum rotates, the direction in which the brake drum wraps the brake band around itself is opposite to the direction in which the brake drum rotates, which means that the braking force of the brake device is reduced.

[0007] Therefore, in the brake device of Patent Document 1, the braking force increases or decreases depending on the rotation direction of the brake drum (shaft member), resulting in a difference in braking force. In brake devices that brake the shaft member using a brake band (band member), there is a demand for suppressing the difference in braking force depending on the rotation direction of the shaft member.

[0008] The present disclosure aims to suppress a difference in braking force depending on the rotation direction of a shaft member in a brake device that brakes a shaft member using a band member.

[0009] A brake device according to one aspect of the present disclosure comprises a band-shaped member that surrounds the outer peripheral surface of a shaft member that rotates around an axis and tightens the shaft member by deforming; a drive unit that is disposed on the band member and drives the band member to cause deformation of the band member; a first contact portion that comes into contact with a first end of the band member to stop the rotation of the band member when the band member rotates in a first direction around the axis; and a second contact portion that comes into contact with a second end of the band member to stop the rotation of the band member when the band member rotates in a second direction opposite to the first direction around the axis.

[0010] When the band member tightens around a shaft member rotating in a first direction, the band member rotates together with the shaft member in the first direction, and the first contact portion comes into contact with the first end of the band member, stopping the rotation of the band member. This generates friction between the band member and the shaft member, braking the shaft member. On the other hand, when the band member tightens around a shaft member rotating in a second direction opposite to the first direction, the band member rotates together with the shaft member in the second direction, and the second contact portion comes into contact with the second end of the band member, stopping the rotation of the band member. This generates friction between the band member and the shaft member, braking the shaft member.

[0011] In this way, when the band member rotates in the first direction, the first contact portion contacts the first end, and when the band member rotates in the second direction, the second contact portion contacts the second end. Therefore, the rotation direction of the shaft member can be set to a direction in which the shaft member wraps around itself, both when the shaft member rotates in the first direction and when the shaft member rotates in the second direction. Therefore, in a brake device that brakes the shaft member using a band member, it is possible to suppress differences in braking force depending on the rotation direction of the shaft member.

[0012] In addition, in a brake device according to one aspect of the present disclosure, the band member comprises a belt-shaped main body member and a contact member arranged on the main body member and in contact with the shaft member, and the friction coefficient of the contact member is greater than the friction coefficient of the main body member.

[0013] This allows the band member to improve its braking force.

[0014] In addition, in a brake device according to one aspect of the present disclosure, the drive device includes a screw shaft that passes through the first end and the second end, an actuator that is fixed to the first end and rotates the screw shaft, and a nut that is fixed to the second end and engages with the screw shaft so as to be rotatable relative to the screw shaft.

[0015] This allows the drive device to reliably deform the band member.

[0016] In addition, in a brake device according to one aspect of the present disclosure, the first contact portion is located on the opposite side of the band member from the shaft member and on the first direction side of the first end, and the second contact portion is located on the opposite side of the band member from the shaft member and on the second direction side of the second end.

[0017] According to this, the first contact portion and the second contact portion can each reliably stop the rotation of the band member.

[0018] In addition, a brake device according to one aspect of the present disclosure further includes a housing that has the first contact portion, the second contact portion, and a connection portion that connects the first contact portion and the second contact portion, and that stores the band member.

[0019] This allows the band member to be protected by the housing.

[0020] According to the present disclosure, in a brake device that brakes a shaft member using a band member, it is possible to suppress a difference in braking force depending on the rotation direction of the shaft member.

[0021] Fig. 1 is a front view of a brake device according to an embodiment of the present disclosure. Fig. 2 is a side view of the brake device as viewed along arrow II shown in Fig. 1. Fig. 3 is a diagram illustrating a state in which the brake device brakes a shaft member rotating in a first direction. Fig. 4 is a diagram illustrating a state in which the brake device brakes a shaft member rotating in a second direction. Fig. 5 is a front view of a brake device according to a first modified example of the embodiment of the present disclosure. Fig. 6 is a front view of a brake device according to a second modified example of the embodiment of the present disclosure. Fig. 7 is a front view of a brake device according to a third modified example of the embodiment of the present disclosure.

[0022] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings, but the present disclosure is not limited thereto. The components of each embodiment described below can be combined as appropriate. In addition, some components may not be used.

[0023] Fig. 1 is a front view of a brake device 1 according to an embodiment of the present disclosure. Fig. 2 is a side view of the brake device 1 as viewed along the arrow II shown in Fig. 1.

[0024] The brake device 1 brakes the rotation of a shaft member 2. FIG. 1 shows a state in which the brake device 1 is not braking the rotation of the shaft member 2. The shaft member 2 is cylindrical and has an axis Ax. The shaft member 2 is held by a holding member (not shown) so as to be rotatable about the axis Ax. The shaft member 2 has a rotating state and a stopped state in which rotation is stopped. The shaft member 2 rotates in a first direction D1 about the axis Ax and in a second direction D2 opposite to the first direction D1. In FIG. 1, the first direction D1 is the counterclockwise direction about the axis Ax, and the second direction D2 is the clockwise direction about the axis Ax.

[0025] The brake device 1 includes a band member 10 , a drive device 20 , and a housing 30 .

[0026] The band member 10 is belt-shaped and surrounds the outer peripheral surface of the shaft member 2. The band member 10 has an arc-shaped inner surface facing the shaft member 2. The band member 10 has a first end 10a, a second end 10b, and an intermediate portion 10c that connects the first end 10a and the second end 10b. The first end 10a, the second end 10b, and the intermediate portion 10c are integral. In the band member 10, there is a gap between the first end 10a and the second end 10b.

[0027] The band member 10 includes a main body member 11 , a contact member 12 , a first bracket portion 13 , and a second bracket portion 14 .

[0028] The main body member 11 is in the shape of a band that surrounds the outer circumferential surface of the shaft member 2. The main body member 11 has an arc-like shape with its inner surface facing the shaft member 2.

[0029] The contact member 12 is disposed on the main body member 11 and comes into contact with the shaft member 2. The contact member 12 is disposed on the inner surface of the main body member 11. When the brake device 1 is not braking the shaft member 2, the inner diameter of the contact member 12 is larger than the outer diameter of the shaft member 2. The friction coefficient of the contact member 12 is larger than the friction coefficient of the main body member 11.

[0030] The first bracket portion 13 is plate-shaped and is fixed to the main body member 11. The first bracket portion 13 is included in the first end portion 10a of the band member 10.

[0031] The second bracket portion 14 is plate-shaped and is fixed to the main body member 11. The second bracket portion 14 is included in the second end portion 10b of the band member 10. The first bracket portion 13 and the second bracket portion 14 face each other.

[0032] When the brake device 1 brakes the rotation of the shaft member 2, the band member 10 deforms so as to fasten the shaft member 2 (details will be described later).

[0033] The driving device 20 is disposed on the band member 10 and drives the band member 10 to deform the band member 10. The driving device 20 includes a screw shaft 21, an actuator 22, and a nut 23.

[0034] The screw shaft 21 passes through the first end 10a and the second end 10b of the band member 10. Specifically, the screw shaft 21 passes through the first through-hole 13a of the first bracket portion 13 and the second through-hole 14a of the second bracket portion 14.

[0035] The actuator 22 is fixed to the first end 10a of the band member 10 and rotates the screw shaft 21. The actuator 22 is fixed to the first bracket portion 13. The actuator 22 is, for example, a motor. The screw shaft 21 is fixed to the output shaft of the actuator 22 so as to be rotatable integrally therewith.

[0036] The nut 23 is fixed to the second end 10b of the band member 10 so as not to rotate relative to the screw shaft 21, and is fitted to the screw shaft 21 so as to be rotatable relative to the screw shaft 21. The nut 23 is fixed to the second bracket portion 14. When the screw shaft 21 rotates, the nut 23 moves along the screw shaft 21.

[0037] As the screw shaft 21 rotates and the nut 23 moves closer to the actuator 22, the first bracket portion 13 and the second bracket portion 14 move closer to each other. This reduces the gap between the first end 10a and the second end 10b, and the band member 10 is deformed so that the inner diameter of the contact member 12 decreases.

[0038] On the other hand, when the screw shaft 21 rotates and the nut 23 moves away from the actuator 22, the first bracket portion 13 and the second bracket portion 14 move away from each other. This increases the gap between the first end 10a and the second end 10b, and the band member 10 is deformed so that the inner diameter of the contact member 12 increases.

[0039] The housing 30 accommodates the band member 10. The housing 30 is fixed to a holding member that holds the shaft member 2. The band member 10 is movable relative to the housing 30.

[0040] The housing 30 is strip-shaped and has a first contact portion 31 located at the first end, a second contact portion 32 located at the second end, and a connecting portion 33 that connects the first contact portion 31 and the second contact portion 32. The first contact portion 31, the second contact portion 32, and the connecting portion 33 are integral with each other.

[0041] The main body member 11 and contact member 12 of the band member 10 are located inside the housing 30. The first bracket portion 13 and the second bracket portion 14 protrude outside the housing 30 from the gap between the first contact portion 31 and the second contact portion 32. In other words, the housing 30 accommodates the main body member 11 and contact member 12 of the band member 10.

[0042] The first contact portion 31 is located on the opposite side of the band member 10 from the shaft member 2 and on the first direction D1 side of the first end portion 10a. Specifically, the first contact portion 31 is located on the first direction D1 side of the first bracket portion 13. When the band member 10 rotates in the first direction D1 around the axis Ax, the first contact portion 31 comes into contact with the first end portion 10a (first bracket portion 13) of the band member 10 to stop the rotation of the band member 10 (details will be described later).

[0043] The second contact portion 32 is located on the opposite side of the band member 10 from the shaft member 2 and on the second direction D2 side of the second end portion 10b. Specifically, the second contact portion 32 is located on the second direction D2 side of the second bracket portion 14. When the band member 10 rotates in the second direction D2 around the axis Ax, the second contact portion 32 comes into contact with the second end portion 10b (second bracket portion 14) of the band member 10 to stop the rotation of the band member 10 (details will be described later).

[0044] Next, the operation of the brake device 1 when braking the rotation of the rotating member will be described.

[0045] FIG. 3 is a diagram showing a state in which the brake device 1 brakes the shaft member 2 rotating in the first direction D1.

[0046] When the brake device 1 brakes the rotation of the shaft member 2, the drive device 20 drives the band member 10 to cause deformation that tightens the shaft member 2. Specifically, in the drive device 20, the screw shaft 21 rotates so that the nut 23 approaches the actuator 22 as described above, thereby deforming the band member 10 and reducing the inner diameter of the contact member 12. As a result, the contact member 12 comes into contact with the shaft member 2, and the band member 10 tightens the shaft member 2.

[0047] When the band member 10 tightens around the shaft member 2, the band member 10 rotates integrally with the shaft member 2 in the first direction D1, and as shown in Figure 3, the first bracket portion 13 comes into contact with the first contact portion 31. This stops the rotation of the band member 10, and the rotation of the shaft member 2 is braked by the friction generated between the contact member 12 and the shaft member 2.

[0048] In this case, the rotation direction (first direction D1) of the shaft member 2 is the direction in which the gap between the first end 10a and the second end 10b of the band member 10 becomes smaller. In other words, the rotation direction (first direction D1) of the shaft member 2 is the direction in which the shaft member 2 wraps around the band member 10. Therefore, the braking force of the brake device 1 increases.

[0049] FIG. 4 is a diagram showing a state in which the brake device 1 brakes the shaft member 2 rotating in the second direction D2.

[0050] In the drive device 20, as described above, the screw shaft 21 rotates so that the nut 23 approaches the actuator 22, deforming the band member 10 and reducing the inner diameter of the contact member 12. As a result, the contact member 12 comes into contact with the shaft member 2, and the band member 10 tightens the shaft member 2.

[0051] When the band member 10 tightens around the shaft member 2, the band member 10 rotates integrally with the shaft member 2 in the second direction D2, and as shown in Figure 4, the second bracket portion 14 comes into contact with the second contact portion 32. This stops the rotation of the band member 10, and the rotation of the shaft member 2 is braked by the friction generated between the contact member 12 and the shaft member 2.

[0052] In this case, the rotation direction (second direction D2) of the shaft member 2 is the direction in which the gap between the first end 10a and the second end 10b of the band member 10 becomes smaller. In other words, the rotation direction (second direction D2) of the shaft member 2 is the direction in which the shaft member 2 wraps around the band member 10. Therefore, the braking force of the brake device 1 increases.

[0053] In this way, when the shaft member 2 rotates in the first direction D1 and when the shaft member 2 rotates in the second direction D2, the rotation direction of the shaft member 2 is the direction in which the braking force of the brake device 1 increases.

[0054] When the brake device 1 stops braking the shaft member 2, the drive device 20 rotates the screw shaft 21 so that the nut 23 moves away from the actuator 22. This causes the band member 10 to deform, increasing the inner diameter of the contact member 12, and the contact member 12 moves away from the shaft member 2, thereby stopping braking of the shaft member 2.

[0055] As described above, according to this embodiment, the brake device 1 comprises: a band-shaped band member 10 that surrounds the outer peripheral surface of the shaft member 2 that rotates around the axis Ax and tightens the shaft member 2 by deforming; a drive unit 20 that is disposed on the band member 10 and drives the band member 10 to cause deformation of the band member 10; a first contact portion 31 that comes into contact with a first end portion 10a of the band member 10 to stop the rotation of the band member 10 when the band member 10 rotates in a first direction D1 about the axis Ax; and a second contact portion 32 that comes into contact with a second end portion 10b of the band member 10 to stop the rotation of the band member 10 when the band member 10 rotates in a second direction D2 opposite to the first direction D1 about the axis Ax.

[0056] When the band member 10 tightens around the shaft member 2 rotating in the first direction D1, the band member 10 rotates integrally with the shaft member 2 in the first direction D1, and the first contact portion 31 comes into contact with the first end 10a of the band member 10, stopping the rotation of the band member 10. This brakes the shaft member 2 as described above. On the other hand, when the band member 10 tightens around the shaft member 2 rotating in a second direction D2 opposite to the first direction D1, the band member 10 rotates integrally with the shaft member 2 in the second direction D2, and the second contact portion 32 comes into contact with the second end 10b of the band member 10, stopping the rotation of the band member 10. This brakes the shaft member 2 as described above.

[0057] In this way, when the band member 10 rotates in the first direction D1, the first contact portion 31 contacts the first end portion 10a, and when the band member 10 rotates in the second direction D2, the second contact portion 32 contacts the second end portion 10b. Therefore, in both cases where the shaft member 2 rotates in the first direction D1 and where the shaft member 2 rotates in the second direction D2, the rotation direction of the shaft member 2 can be set to a direction in which the shaft member 2 wraps around itself the band member 10. Therefore, in the brake device 1 that brakes the shaft member 2 using the band member 10, it is possible to suppress differences in braking force depending on the rotation direction of the shaft member 2.

[0058] The band member 10 includes a belt-shaped main body member 11 and a contact member 12 that is disposed on the main body member 11 and comes into contact with the shaft member 2. The coefficient of friction of the contact member 12 is greater than the coefficient of friction of the main body member 11.

[0059] As a result, the band member 10 can improve the braking force of the brake device 1.

[0060] The drive device 20 also includes a screw shaft 21 that passes through the first end 10a and the second end 10b, an actuator 22 that is fixed to the first end 10a and rotates the screw shaft 21, and a nut 23 that is fixed to the second end 10b and engages with the screw shaft 21 so as to be rotatable relative to the screw shaft 21.

[0061] This allows the drive device 20 to reliably deform the band member 10 .

[0062] The first contact portion 31 is located on the opposite side of the band member 10 from the shaft member 2 and closer to the first direction D1 than the first end portion 10a. The second contact portion 32 is located on the opposite side of the band member 10 from the shaft member 2 and closer to the second direction D2 than the second end portion 10b.

[0063] This allows the first contact portion 31 and the second contact portion 32 to reliably stop the rotation of the band member 10 .

[0064] The brake device 1 also includes a housing 30 that has a first contact portion 31, a second contact portion 32, and a connection portion 33 that connects the first contact portion 31 and the second contact portion 32, and that houses the band member 10.

[0065] According to this, the brake device 1 can protect the band member 10 by the housing 30 .

[0066] Next, a brake device 1 according to a modified example of the embodiment of the present disclosure will be described, focusing mainly on the differences from the above-described embodiment.

[0067] 5 is a front view showing a brake device 1 according to a first modified example of the embodiment of the present disclosure. In this first modified example, the brake device 1 does not include the housing 30 of the above embodiment, but includes a first contact portion 131 and a second contact portion 132 as separate members. The first contact portion 131 and the second contact portion 132 are each rod-shaped and extend along the axis Ax, and are held by a holding member. The band member 10 is movable relative to the first contact portion 131 and the second contact portion 132.

[0068] 6 is a front view showing a brake device 1 according to a second modified example of the embodiment of the present disclosure. In FIG. 6, a first direction D1 is a clockwise direction around the axis Ax, and a second direction D2 is a counterclockwise direction around the axis Ax.

[0069] In the second modified example, the brake device 1 does not include the housing 30 of the above embodiment, but includes a pillar member 240. The pillar member 240 has a pillar shape extending along the axis Ax. The pillar member 240 is located between the first bracket portion 13 and the second bracket portion 14.

[0070] The pillar member 240 has a first contact portion 241 , a second contact portion 242 , and a connection portion 243 that connects the first contact portion 241 and the second contact portion 242 .

[0071] When the band member 10 rotates in a first direction D1 about the axis Ax, the first contact portion 241 comes into contact with the first end portion 10a (first bracket portion 13) of the band member 10 to stop the rotation of the band member 10. When the band member 10 rotates in a second direction D2 about the axis Ax, the second contact portion 242 comes into contact with the second end portion 10b (second bracket portion 14) of the band member 10 to stop the rotation of the band member 10.

[0072] In this second modified example, the rotation direction (first direction D1) of the shaft member 2 is the direction in which the gap between the first end 10a and the second end 10b of the band member 10 increases when the brake device 1 brakes the rotation of the shaft member 2. In other words, the rotation direction of the shaft member 2 is opposite the direction in which the shaft member 2 wraps around the band member 10. Therefore, the braking force of the brake device 1 decreases.

[0073] Furthermore, the rotation direction of the shaft member 2 (second direction D2) is the direction in which the gap between the first end 10a and the second end 10b of the band member 10 increases when the brake device 1 brakes the rotation of the shaft member 2. In other words, the rotation direction of the shaft member 2 is opposite the direction in which the shaft member 2 wraps around the band member 10. Therefore, the braking force of the brake device 1 decreases.

[0074] As described above, in the second modified example, when the shaft member 2 rotates in the first direction D1 and when the shaft member 2 rotates in the second direction D2, the rotation direction of the shaft member 2 is a direction in which the braking force of the brake device 1 decreases. Therefore, in the brake device 1 that brakes the shaft member 2 using the band member 10, it is possible to suppress the difference in braking force depending on the rotation direction of the shaft member 2.

[0075] FIG. 7 is a front view showing a brake device 1 according to a third modified example of the embodiment of the present disclosure.

[0076] In the third modified example, the driving device 320 is a solenoid device, i.e., a so-called push solenoid, and includes a movable iron core 321 and a case 322.

[0077] The driving device 320 is disposed at a position where the gap between the first end 10a and the second end 10b is reduced by the movable iron core 321 protruding from the case 322 and pressing the first bracket portion 13. The second bracket portion 314 has a U-shaped cross section with the first bracket portion 13 located on the inside. The case 322 is fixed to the second bracket portion 314.

[0078] The movable iron core 321 protrudes from the case 322 and presses the first bracket portion 13. This reduces the gap between the first end 10a and the second end 10b, and the band member 10 is deformed so as to reduce the inner diameter of the contact member 12. Due to the deformation of the band member 10, the rotation of the shaft member 2 is braked as described above.

[0079] Furthermore, in the brake device 1 of the above embodiment and the brake device 1 of each modification, the band member 10 does not have to include the first bracket portion 13 and the second bracket portion 14. In this case, the band member 10 has, for example, a U-shaped cross section, and if the drive device 20 includes a screw shaft 21, the screw shaft 21 passes through the first end portion 10 a and the second end portion 10 b.

[0080] Furthermore, the band member 10 does not need to include the contact member 12. In this case, the band member 10 is deformed, and friction occurs between the main body member 11 and the shaft member 2, thereby braking the rotation of the shaft member 2.

[0081] Furthermore, a contact member 12 may be disposed on the outer peripheral surface of the shaft member 2. In this case, the band member 10 is deformed, and friction occurs between the main body member 11 and the contact member 12, thereby braking the rotation of the shaft member 2.

[0082] REFERENCE SIGNS LIST 1 Brake device 2 Shaft member 10 Band member 10a First end 10b Second end 11 Body member 12 Contact member 20 Drive device 21 Screw shaft 22 Actuator 23 Nut 30 Housing 31 First contact portion 32 Second contact portion 33 Connection portion Ax Axis line D1 First direction D2 Second direction

Claims

1. A brake device comprising: a band-shaped band member that surrounds the outer peripheral surface of a shaft member that rotates about an axis and tightens the shaft member by deforming; a drive device that is disposed on the band member and drives the band member to cause deformation of the band member; a first contact portion that comes into contact with a first end of the band member to stop the rotation of the band member when the band member rotates in a first direction about the axis; and a second contact portion that comes into contact with a second end of the band member to stop the rotation of the band member when the band member rotates in a second direction about the axis that is opposite to the first direction.

2. A brake device as set forth in claim 1, wherein the band member comprises: a strip-shaped main body member; and a contact member disposed on the main body member and in contact with the shaft member, the coefficient of friction of the contact member being greater than the coefficient of friction of the main body member.

3. The brake device according to claim 1, wherein the drive device comprises: a threaded shaft penetrating the first end and the second end; an actuator fixed to the first end for rotating the threaded shaft; and a nut fixed to the second end for engaging with the threaded shaft so as to be rotatable relative to the threaded shaft.

4. A brake device as described in claim 1, wherein the first contact portion is located on the opposite side of the band member from the shaft member and on the first direction side of the first end, and the second contact portion is located on the opposite side of the band member from the shaft member and on the second direction side of the second end.

5. A brake device according to claim 4, further comprising a housing that has the first contact portion, the second contact portion, and a connection portion that connects the first contact portion and the second contact portion, and that houses the band member.

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