Electric braking device

Abstract

Regarding the electric braking system, it is equipped with a mechanism to release residual axial force while suppressing deterioration of kinetic energy transmission efficiency. [Solution] This invention relates to an electric braking device that moves a piston for generating braking force by converting the rotational motion of a rotating part 71, to which the rotational motion of an electric motor is transmitted, into linear motion. The electric braking device includes a release mechanism 20 having an intermediate member 40 to which one end of a torsion coil spring 24 is connected. The release mechanism 20 connects the intermediate member 40 and the rotating part 71 when the rotation angle of the rotating part 71 is less than a first angle, and disconnects them when the rotation angle is greater than or equal to the first angle. When the intermediate member 40 is connected to the rotating part 71, the release mechanism 20 stores elastic force when the rotating part 71 rotates in a direction that increases the braking force, and when the elastic force is released, it rotates the rotating part 71 in a direction that decreases the braking force. The release mechanism 20 can retain the stored elastic force when the intermediate member 40 is disconnected from the rotating part 71.

Description

Technical Field

[0001] The present invention relates to an electric brake device.

Background Art

[0002] Patent Document 1 discloses an electric brake device. The electric brake device disclosed in Patent Document 1 includes a residual axial force releasing mechanism. This mechanism includes a sloped surface provided on an inner clutch, a ball provided in a groove of an outer clutch, and a spring that presses the ball toward the inner clutch. A part of the ball protrudes from the groove of the outer clutch. It is described that this mechanism accumulates elastic force in the spring during normal rotation, and releases the elastic force of the spring during reverse rotation. It is described that in this mechanism, the elastic force accumulated in the spring is held when the rotation amount is equal to or greater than a predetermined rotation amount.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0004] In the residual axial force releasing mechanism as disclosed in Patent Document 1, the ball protruding from the groove of the outer clutch is in contact with the sloped surface of the inner clutch, which prevents the ball from falling off the sloped surface of the inner clutch. In such a configuration, the ball remains in continuous contact with the sloped surface of the inner clutch. For this reason, when the electric motor of the electric brake device is rotated in the normal direction to increase the braking force applied to the wheel, the elastic force of the spring assembled to support the ball acts as a resistance force. There has been a problem that this resistance force reduces the transmission efficiency of kinetic energy.

Means for Solving the Problems

[0005] An electric braking device for solving the above problems is provided, which is driven by an electric motor and includes a linear motion conversion mechanism that converts the rotational motion of a rotating part into linear motion of a linear motion part, and generates braking force on the wheel by pressing a brake friction material, which is linked to the linear motion of the linear motion part, against a brake rotating body that rotates integrally with the wheel, and comprises an energy storage part that, in a connected state connected to the rotating part, is deformed by the rotation of the rotating part in a direction that increases the braking force and stores elastic force, and when the stored elastic force is released, rotates the rotating part in a direction that decreases the braking force, and in an unconnected state separated from the rotating part, holds the stored elastic force, and a switching part that, when the rotation angle of the rotating part is less than a first angle, connects the energy storage part and the rotating part, and when the rotation angle of the rotating part is the first angle or greater, disconnects the energy storage part and the rotating part. [Effects of the Invention]

[0006] It is possible to suppress deterioration of kinetic energy transmission efficiency while incorporating a mechanism to release residual axial force. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic diagram showing the general configuration of the electric braking device of the first embodiment. [Figure 2] Figure 2 is a cross-sectional view showing the release mechanism of the electric braking system shown in Figure 1. [Figure 3] Figure 3 is a plan view showing the terminal member in the release mechanism of Figure 2. [Figure 4] Figure 4 is a plan view showing the intermediate member in the release mechanism of Figure 2. [Figure 5] Figure 5 is a plan view showing the main rotating member in the release mechanism of Figure 2. [Figure 6] Figure 6 is a plan view of the release mechanism shown in Figure 2. [Figure 7] Figure 7 is a schematic diagram illustrating the operation of the release mechanism shown in Figure 2. [Figure 8]Figure 8 is a schematic diagram illustrating the operation of the release mechanism shown in Figure 2. [Figure 9] Figure 9 is a schematic diagram illustrating the operation of the release mechanism shown in Figure 2. [Figure 10] Figure 10 is a schematic diagram illustrating the operation of the release mechanism shown in Figure 2. [Figure 11] Figure 11 is a schematic diagram illustrating the operation of the release mechanism shown in Figure 2. [Figure 12] Figure 12 shows the changes in the rotation angle and generated torque of the rotating part in the electric braking device shown in Figure 1. [Figure 13] Figure 13 is a schematic diagram showing the release mechanism in the electric braking system of the second embodiment. [Figure 14] Figure 14 is a schematic diagram illustrating the operation of the release mechanism shown in Figure 13. [Figure 15] Figure 15 is a schematic diagram illustrating the operation of the release mechanism shown in Figure 13. [Figure 16] Figure 16 is a schematic diagram illustrating the operation of the release mechanism shown in Figure 13. [Figure 17] Figure 17 is a schematic diagram illustrating the operation of the release mechanism shown in Figure 13. [Modes for carrying out the invention]

[0008] (First Embodiment) The electric braking device of the first embodiment will be described with reference to the drawings. <Electric braking device> As shown in Figure 1, the electric braking device 10 comprises an electric motor 63, a transmission mechanism 65, a linear motion conversion mechanism 70, an axial force sensor 66, a thrust bearing 67, a cylinder 61, a piston 62, and a brake friction material 12. The electric braking device 10 is a braking device that generates braking force on the wheels by pressing the brake friction material 12 against a brake rotating body 11 that rotates integrally with the vehicle's wheels.

[0009] The linear motion conversion mechanism 70 includes a rotating portion 71 and a linear motion portion 74. The linear motion conversion mechanism 70 is, for example, a feed screw mechanism, but may also be a ball screw mechanism. The linear motion portion 74 is movable forward and backward in the direction along the rotation axis C1 of the rotating portion 71. Of the directions along the rotation axis C1, one is the forward direction X1, and the other is the backward direction X2.

[0010] The transmission mechanism 65 transmits the rotational motion of the output shaft of the electric motor 63 to the rotating portion 71 in the linear motion conversion mechanism 70. The cylinder 61 is formed in a cylindrical shape inside the cylinder inner wall 61a. The piston 62 has a disk-shaped end wall and a cylindrical portion extending from the end wall. The piston 62 is accommodated in the cylinder 61. The end wall of the piston 62 faces the brake friction material 12. The piston 62 covers the linear motion portion 74 of the linear motion conversion mechanism 70 from the radially outer side. The end of the linear motion portion 74 in the forward direction X1 is in contact with the end wall of the piston 62. The piston 62 moves in conjunction with the linear motion of the linear motion portion 74. The brake friction material 12 can be moved by the linear motion of the piston 62.

[0011] The forward direction X1 corresponds to the direction that increases the braking force. When the linear motion portion 74 moves in the forward direction X1, the linear motion portion 74 moves the piston 62 in the forward direction X1. As a result, the brake friction material 12 can be pressed against the brake rotating body 11, so that a braking force can be generated. On the other hand, the backward direction X2 corresponds to the direction that decreases the braking force. When the linear motion portion 74 moves in the backward direction X2, the linear motion portion 74 moves the piston 62 in the backward direction X2.

[0012] The linear motion conversion mechanism 70 will be described in more detail with reference to Figure 1. The rotating portion 71 has a screw shaft 72 and a flange 73. The rotation axis C1 is a line along the axial center of the screw shaft 72 of the rotating portion 71. The linear motion portion 74 has a screw hole 75. The screw hole 75 corresponds to the screw shaft 72.

[0013] In the linear motion conversion mechanism 70, the rotation of the rotating part 71 in the first rotational direction R1 allows the linear motion part 74 to move in the forward direction X1, that is, in the direction that increases the braking force. In the linear motion conversion mechanism 70, the rotation of the rotating part 71 in the second rotational direction R2 allows the linear motion part 74 to move in the reverse direction X2, that is, in the direction that decreases the braking force.

[0014] When viewing the rotating part 71 from the end in the retraction direction X2 to the end in the advance direction X1, the clockwise rotation direction is the first rotation direction R1, and the counterclockwise rotation direction is the second rotation direction R2.

[0015] In the following, the forward direction X1 or the backward direction X2 may be referred to as the axial direction. Also, the first rotational direction R1 or the second rotational direction R2 may be referred to as the circumferential direction. The position of the piston 62 at which the brake friction material 12 begins to contact the brake rotating body 11 is called the contact start position. The rotation angle of the electric motor 63 when the piston 62 is positioned at the contact start position is called the contact angle P0. Furthermore, the rotation angle at which the remaining axial force is maximized when the power supply to the electric braking device 10 is lost during braking is called the first angle P1. The first angle P1 is the rotation angle of the electric motor 63 when the rotating part 71 rotates by a predetermined angle in the first rotation direction R1 from the contact angle P0. In other words, the first angle P1 is a rotation angle that is larger than the contact angle P0.

[0016] The second angle P2 is defined as the rotation angle of the electric motor 63 that is larger than the first angle P1 and at which the force with which the piston 62 presses the brake friction material 12 against the brake rotating body 11 is maximized.

[0017] The position where the piston 62 has moved a predetermined distance in the backward direction X2 from the contact start position is called the standby position. The rotation angle of the electric motor 63 when the piston 62 is positioned in the standby position is called the standby position angle PY.

[0018] Furthermore, the operating angle PZ is set as the rotation angle of the electric motor 63 between the standby position angle PY and the contact angle P0 described above. The release mechanism 20, which will be described later, is configured to switch whether or not the elastic force stored in the energy storage unit U1 acts on the rotating unit 71 at the operating angle PZ. The operating angle PZ can be set to any rotation angle as long as it is between the standby position angle PY and the contact angle P0.

[0019] As will be described later, the position at which the main rotating member 30 and the end member 50 engage when the main rotating member 30 is rotated in the second rotation direction R2 is called the rear end position. The rear end position is the position where the piston 62 is moved further back in the reverse direction X2 than the standby position. The rotation angle of the electric motor 63 when the piston 62 is positioned at the rear end position is called the rear end position angle PX.

[0020] The electric braking device 10 adjusts the braking force by controlling the rotation angle between the standby position angle PY and the second angle P2 when applying braking force. In this specification, each of the above rotation angles is described as a rotation angle based on the state in which wear, thermal expansion, aging, etc., due to the use of the brake friction material 12, etc., have not occurred, or more precisely, the state of the electric braking device 10 immediately after manufacture.

[0021] The electric braking system 10 is equipped with a release mechanism 20. The release mechanism 20 is located inside the cylinder 61. As shown in Figure 1, the transmission mechanism 65, axial force sensor 66, thrust bearing 67, flange 73, release mechanism 20, and screw shaft 72 are arranged in this order along the rotation axis C1 in the forward direction X1.

[0022] <Release mechanism> [Outline of the release mechanism] The release mechanism 20 is a mechanical return mechanism that eliminates the braking force by releasing the remaining axial force when the power supply to the electric braking device 10 is lost.

[0023] The release mechanism 20 includes an energy storage unit U1 and a switching unit U2. The energy storage unit U1 can be switched between a connected state, where it is connected to the rotating unit 71, and an unconnected state, where it is not connected.

[0024] The switching unit U2 can switch the connection configuration of the energy storage unit U1 to the rotating unit 71. An example of the switching unit U2 is a ball lamp mechanism. The energy storage unit U1 can store elastic force when the rotating unit 71 rotates in a direction that increases the braking force, while the energy storage unit U1 is connected to the rotating unit 71.

[0025] The energy storage unit U1 can retain the stored elastic force even when it is separated from the rotating unit 71, i.e., when it is not connected. When the energy storage unit U1 is connected to the rotating unit 71, the stored elastic force is released, and the energy storage unit U1 can apply a force to the rotating unit 71 that rotates the rotating unit 71 in a direction that reduces the braking force.

[0026] The switching unit U2 connects the energy storage unit U1 and the rotating unit 71 when the rotation angle of the rotating unit 71 is less than the first angle P1. The switching unit U2 disconnects the energy storage unit U1 and the rotating unit 71 when the rotation angle of the rotating unit 71 is greater than or equal to the first angle P1.

[0027] [Configuration of the release mechanism] The specific configuration of the release mechanism 20 will be explained using Figures 2-6 and Figure 7. The configuration described below is an example of a configuration that functions as an energy storage unit U1 and a switching unit U2.

[0028] As shown in Figure 2, the release mechanism 20 comprises a main rotating member 30, an intermediate member 40, an end member 50, a torsion coil spring 24, a holding member 28, and a regulating member 29. As shown in Figures 2 and 3, the terminal member 50 comprises a peripheral wall 56 with a circular cross-section and an end wall 55 located at one end of the peripheral wall 56. The end of the peripheral wall 56 opposite to the end wall 55 of the terminal member 50 is open. As shown in Figure 2, the terminal member 50 is positioned such that the end wall 55 is located at the end in the retraction direction X2 and the opening is located at the end in the advance direction X1. As shown in Figure 2, a regulating member 29 is positioned in the cylinder 61 having a release mechanism 20 in the retraction direction X2 relative to the end wall 55. The regulating member 29 restricts the terminal member 50 from moving in the retraction direction X2.

[0029] As shown in Figures 2 and 4, the intermediate member 40 is formed in the shape of a disc. As shown in Figures 2 and 5, the main rotating member 30 is formed in the shape of a disc. As shown in Figure 2, the intermediate member 40 is positioned inside the terminal member 50. As shown in Figure 2, the main rotating member 30 is positioned inside the terminal member 50. The intermediate member 40 and the main rotating member 30 are positioned sequentially from the end wall 55 of the terminal member 50 toward the forward direction X1. That is, the terminal member 50 is positioned on the opposite side of the intermediate member 40 from the main rotating member 30. Figure 6 is a plan view of the release mechanism 20 as seen from the main rotating member 30 side. In Figure 6, the main rotating member 30, intermediate member 40 and terminal member 50 of the release mechanism 20 are shown, and the other members are not shown.

[0030] Figure 7 schematically shows the components of the release mechanism 20. The release mechanism 20 includes a ball 22, as shown in Figure 7. As will be described in more detail later, the release mechanism 20 has two balls 22.

[0031] [Ending member] As shown in Figures 2, 3, and 6, the peripheral wall 56 of the end member 50 is provided with a first spring connection portion 54. The first end of the torsion coil spring 24 is attached to the first spring connection portion 54, as will be described later. The first spring connection portion 54 is formed, for example, as a notch at the end of the peripheral wall 56 opposite to the end wall 55.

[0032] As shown in Figure 2, the end wall 55 of the end member 50 is provided with a through-hole, the end shaft hole 51. The end shaft hole 51 penetrates from one of the two planar circular surfaces of the end wall 55 to the other surface. The end shaft hole 51 penetrates the center of the two planar circular surfaces of the end wall 55. The rotating part 71 is inserted into the end shaft hole 51. The end member 50 is positioned such that the center of the end shaft hole 51 is located on the rotation axis C1. The diameter of the end shaft hole 51 is larger than the diameter of the portion of the rotating part 71 that is inserted into the end shaft hole 51. For this reason, the end member 50 is not directly fixed to the rotating part 71.

[0033] As shown in Figures 3 and 6, the end wall 55 facing the forward direction X1 is provided with a ball housing portion 52. The ball housing portion 52 is a non-penetrating groove. The ball housing portion 52 is, for example, a ramp groove. The axial depth of the ramp groove changes gradually in the circumferential direction. In the ramp groove, the portion where the depth changes gradually is called the inclined portion. In the ramp groove, the portion with the maximum depth is called the bottom. The end of the bottom of the ramp groove opposite to the inclined portion is called the ramp end. The ball housing portion 52 may also be a groove that does not have a portion where the depth changes gradually in the axial direction.

[0034] As shown in Figures 3 and 6, the terminal member 50 is provided with a connecting portion 53. The connecting portion 53 is columnar in shape and protrudes from the end wall 55 toward the forward direction X1. Details of the connecting portion 53 will be described later.

[0035] The terminal member 50 has two sets, each consisting of one ball housing section 52 and one connecting section 53. As shown in Figures 3 and 6, the ball housing sections 52 and connecting sections 53 are arranged alternately in the circumferential direction. The sets consisting of the ball housing sections 52 and connecting sections 53 are rotationally symmetrical with respect to a point on the axis of rotation C1.

[0036] [Intermediate component] As shown in Figures 2, 4, and 6, the intermediate member 40 is provided with a second spring connector 44. The second end of the torsion coil spring 24 is attached to the second spring connector 44, as will be described later. The second spring connector 44 is formed on the edge of the intermediate member 40, for example, as a notch.

[0037] As shown in Figure 2, the intermediate member 40 is provided with an intermediate shaft hole 41, which is a through hole. The intermediate shaft hole 41 penetrates from one of the two planar circular surfaces of the intermediate member 40 to the other surface. The intermediate shaft hole 41 penetrates the center of the two planar circular surfaces of the intermediate member 40. The rotating part 71 is inserted into the intermediate shaft hole 41. The intermediate member 40 is positioned such that the center of the intermediate shaft hole 41 is located on the rotation axis C1. The diameter of the intermediate shaft hole 41 is larger than the diameter of the portion of the rotating part 71 that is inserted into the intermediate shaft hole 41. For this reason, the intermediate member 40 is not directly fixed to the rotating part 71.

[0038] As shown in Figures 4 and 6, the intermediate member 40 is provided with a ball hole 42, which is a through hole in the axial direction. The ball hole 42 is capable of accommodating a ball 22. For example, the ball hole 42 has a diameter that is the diameter of the ball 22 plus a predetermined clearance. When a ball 22 is inside the ball hole 42, the movement of the ball 22 in the circumferential and radial directions within the hole can be restricted.

[0039] As shown in Figures 4 and 6, the intermediate member 40 is provided with a second connecting hole 43, which is a through hole in the axial direction. The second connecting hole 43 has an arc shape when viewed in the axial direction. Details of the second connecting hole 43 will be described later.

[0040] The intermediate member 40 has two sets, each consisting of one ball hole 42 and one second connecting hole 43. As shown in Figures 4 and 6, the ball holes 42 and the second connecting holes 43 are arranged alternately in the circumferential direction. The sets of ball holes 42 and second connecting holes 43 are rotationally symmetrical with respect to a point on the axis of rotation C1.

[0041] As shown in Figures 6 and 7, the intermediate member 40 is positioned such that the ball hole 42 corresponds to the ball housing portion 52 of the terminal member 50. As shown in Figures 6 and 7, the connecting portion 53 of the end member 50 is inserted into the second connecting hole 43. Therefore, the range in which the intermediate member 40 can rotate relative to the end member 50 is determined by the circumferential length of the second connecting hole 43. Specifically, when the connecting portion 53 contacts the rear end of the second connecting hole 43 in the first rotation direction R1, the rotation of the intermediate member 40 relative to the end member 50 in the first rotation direction R1 is restricted. When the connecting portion 53 contacts the rear end of the second connecting hole 43 in the second rotation direction R2, the rotation of the intermediate member 40 relative to the end member 50 in the second rotation direction R2 is restricted.

[0042] [Main rotating member] As shown in Figures 2, 5, and 6, the main rotating member 30 is provided with a mounting shaft hole 31, which is a through hole. The mounting shaft hole 31 penetrates from one of the two planar circular faces of the main rotating member 30 to the other face. The mounting shaft hole 31 penetrates the center of the two planar circular faces of the main rotating member 30. The main rotating member 30 is positioned such that the center of the mounting shaft hole 31 is located on the rotation axis C1. The main rotating member 30 is fixed to the rotating part 71, which is inserted into the mounting shaft hole 31. The main rotating member 30 rotates integrally with the rotating part 71.

[0043] As shown in Figures 5 and 6, the main rotating member 30 includes a flat portion 30a and a ramp groove 32 formed in the flat portion 30a. The flat portion 30a corresponds to one of the circular surfaces of the main rotating member 30. The main rotating member 30 is positioned such that the flat portion 30a is located in a plane perpendicular to the rotation axis C1 of the rotating part 71. The flat portion 30a is the surface of the main rotating member 30 facing the retraction direction X2. Therefore, the intermediate member 40 is positioned on the main rotating member 30 opposite the flat portion 30a, which is the surface having the ramp groove 32.

[0044] The ramp groove 32 has an arc shape when viewed in the axial direction. The depth of the ramp groove 32 in the axial direction gradually changes in the circumferential direction. As shown in Figure 7, the portion of the ramp groove 32 where the depth gradually changes is called the inclined portion 32a. The portion of the ramp groove 32 with the maximum depth is called the bottom portion 32b. The end of the bottom portion 32b of the ramp groove 32 that is opposite to the inclined portion 32a is called the ramp end 32c.

[0045] As shown in Figures 5 and 6, the main rotating member 30 is provided with a first connecting hole 33, which is a through hole in the axial direction. The first connecting hole 33 has an arc shape when viewed in the axial direction. Details of the first connecting hole 33 will be described later.

[0046] The main rotating member 30 has two sets, each consisting of one ramp groove 32 and one first connecting hole 33. As shown in Figures 5 and 6, the ramp grooves 32 and the first connecting holes 33 are arranged alternately in the circumferential direction. The sets of ramp grooves 32 and first connecting holes 33 are rotationally symmetrical with respect to a point on the rotation axis C1.

[0047] As shown in Figures 6 and 7, the driving rotating member 30 is positioned such that the ramp groove 32 corresponds to the ball hole 42 of the intermediate member 40. A ball 22 is placed in each ball hole 42. In other words, the release mechanism 20 is equipped with two balls 22.

[0048] As shown in Figures 6 and 7, the connecting portion 53 of the end member 50 is inserted into the first connecting hole 33. Therefore, the range in which the main rotating member 30 can rotate relative to the end member 50 is determined by the circumferential length of the first connecting hole 33. Specifically, when the connecting portion 53 contacts the rear end of the first connecting hole 33 in the first rotation direction R1, the rotation of the main rotating member 30 relative to the end member 50 in the first rotation direction R1 is restricted. When the connecting portion 53 contacts the rear end of the first connecting hole 33 in the second rotation direction R2, the rotation of the main rotating member 30 relative to the end member 50 in the second rotation direction R2 is restricted. If the main rotating member 30 is to be rotated further while its relative rotation with respect to the end member 50 is restricted, a force in the same direction as the rotation direction of the main rotating member 30 is applied to the end member 50.

[0049] [Torsion coil spring] As shown in Figure 2, the torsion coil spring 24 comprises a coil-shaped spring portion 25, a first arm portion 26 which is the first end of the spring portion 25, and a second arm portion 27 which is the second end of the spring portion 25. Hereinafter, the torsion coil spring 24 may be referred to as spring 24. The first arm portion 26 protrudes radially outward from the coil. The first arm portion 26 is fixed to the first spring connection portion 54 of the end member 50. The second arm portion 27 protrudes radially inward from the coil. The second arm portion 27 is fixed to the second spring connection portion 44 of the intermediate member 40. The spring portion 25 is located inside the end member 50. The driving rotation member 30 and the intermediate member 40 are located inside the spring portion 25.

[0050] The spring portion 25 of the torsion coil spring 24 is formed such that it can store elastic force by deforming when the intermediate member 40 rotates relative to the terminal member 50 by rotating the intermediate member 40 in the first rotational direction R1.

[0051] The release mechanism 20 is configured such that the elastic force of the torsion coil spring 24 is preloaded by a predetermined amount when the intermediate member 40 is restricted from rotating in the second rotational direction R2 relative to the terminal member 50.

[0052] [Retaining member] As shown in Figure 2, the retaining member 28 is interposed between the inner wall 61a of the cylinder and the outer wall 56a of the peripheral wall 56 of the end member 50. The retaining member 28 is, for example, an elastic member with an annular cross-section. A specific example of the retaining member 28 is a tolerance ring.

[0053] The retaining member 28 holds the end member 50 within the cylinder 61 by frictional force. The retaining member 28 slides the end member 50 within the cylinder 61 when the force that rotates the end member 50 in the first rotational direction R1 or the second rotational direction R2 is greater than or equal to a specified value. This specified value is greater than the maximum value of the elastic force stored in the spring 24. Therefore, the retaining member 28 can hold the end member 50 so that it does not rotate relative to the cylinder 61 when the release mechanism 20 stores elastic force in the spring 24 and when the release mechanism 20 releases the elastic force of the spring 24.

[0054] Furthermore, if the inner wall 61a of the cylinder forming the cylinder 61 can be processed to have the same function as the retaining member 28, the retaining member 28 can be omitted and the end member 50 can be held inside the cylinder 61.

[0055] [Energy storage unit and switching unit] The energy storage section U1 in the release mechanism 20 described above includes an intermediate member 40, a terminal member 50, and a torsion coil spring 24. The switching section U2 in the release mechanism 20 includes a main rotating member 30, a ball 22, and an intermediate member 40.

[0056] <Operation of the release mechanism> The operation of the energy storage unit U1 and the switching unit U2 in the release mechanism 20 will be explained using Figures 7 to 11. For the sake of explanation, Figures 7 to 11 schematically show the various components of the release mechanism 20. Therefore, Figures 7 to 11 do not accurately represent the shape and dimensions of each component.

[0057] Figures 7-11 show one ramp groove 32, one ball hole 42 and one ball housing 52, as well as one first connecting hole 33, one second connecting hole 43 and one connecting part 53, respectively. One ball 22 is positioned corresponding to one ramp groove 32, one ball hole 42 and one ball housing 52. The above configurations will be described below. Although not shown in the figures, the other ball 22 is positioned corresponding to the other ramp groove 32, the other ball hole 42 and the other ball housing 52. The other ramp groove 32, the other ball hole 42, the other ball housing 52 and the other ball 22, as well as the other first connecting hole 33, the other second connecting hole 43 and the other connecting part 53, perform the same operations as described below, so their description will be omitted.

[0058] Figure 7 shows the state of the release mechanism 20 when the rotation angle of the rotating part 71 is the operating angle PZ. As described above, the operating angle PZ is less than the contact angle P0. First, we will explain the case where the rotating part 71 rotates in the first rotational direction R1.

[0059] In the state shown in Figure 7, the balls 22 are located in the ramp groove 32 of the main rotating member 30 and in the ball holes 42 of the intermediate member 40. More specifically, the balls 22 are located in the inclined portion 32a of the ramp groove 32 and in the ball holes 42 of the intermediate member 40.

[0060] When the main rotating member 30 is rotated in the first rotation direction R1 from the state shown in Figure 7, the ball 22 is fixed in the ball hole 42 between the inclined portion 32a in the ramp groove 32 of the main rotating member 30 and the intermediate member 40. As a result, the main rotating member 30 and the intermediate member 40 are connected via the ball 22. This connects the rotating part 71 and the energy storage part U1. The release mechanism 20 is configured such that when the rotation angle of the rotating part 71 becomes greater than the operating angle PZ, the elastic force stored in the spring 24 acts on the main rotating member 30 via the intermediate member 40.

[0061] By rotating the intermediate member 40, which is connected to the main rotating member 30, in the first rotational direction R1, the intermediate member 40 rotates relative to the terminal member 50. As the intermediate member 40 rotates relative to the terminal member 50 in the first rotational direction R1, elastic force is stored in the spring 24.

[0062] Figure 8 shows the state in which the main rotating member 30 has been further rotated in the first rotational direction R1 from the state shown in Figure 7. As the intermediate member 40 rotates relative to the terminal member 50, the connecting portion 53 of the terminal member 50 is in contact with the end of the second connecting hole 43 of the intermediate member 40. As shown in Figure 8, when the connecting portion 53 of the terminal member 50 is in contact with the end of the second connecting hole 43 of the intermediate member 40, further rotation of the intermediate member 40 in the first rotational direction R1 is restricted.

[0063] When the main rotating member 30 is further rotated in the first rotation direction R1 from the state shown in Figure 8, the ball 22 is pushed out by the inclined portion 32a of the ramp groove 32 and rides onto the flat portion 30a. Further pushing of the ball 22 by the flat portion 30a causes the ball 22 to move toward the end member 50. As a result, as shown in Figure 9, the ball 22 is housed in the ball hole 42 and the ball housing portion 52 facing the ball hole 42. This separates the main rotating member 30 and the intermediate member 40, making them unconnected. The release mechanism 20 is configured such that when the rotation angle of the rotating portion 71 becomes greater than or equal to the first angle P1, the main rotating member 30 and the intermediate member 40 become unconnected.

[0064] The configuration in which the relative rotation of the intermediate member 40 with respect to the terminal member 50 is suppressed is not limited to the above configuration. For example, when the main rotating member 30 is further rotated in the first rotation direction R1 as described above from the state corresponding to Figure 7, the ball 22 may move from the inclined portion 32a of the ramp groove 32 and be housed in the ball housing portion 52, thereby suppressing the relative rotation of the intermediate member 40 with respect to the terminal member 50. In this case, the intermediate member 40 and the terminal member 50 are connected via the ball 22 as the ball 22 is positioned in the ball hole 42 and the ball housing portion 52. In such a configuration, when the ball 22 is housed in the ball housing portion 52, the connecting portion 53 does not have to be in contact with the end of the second connecting hole 43, or, as in the example described above, the connecting portion 53 may be in contact with the end of the second connecting hole 43.

[0065] As shown in Figure 9, when the ball 22 is located in the ball hole 42 and the ball housing portion 52, if the flat portion 30a faces the ball hole 42, the flat portion 30a restricts the movement of the ball 22 in the forward direction X1. For this reason, the ball 22 is fixed by the intermediate member 40 and the terminal member 50. That is, the intermediate member 40 and the terminal member 50 are connected via the ball 22. In this way, the energy storage unit U1 maintains the elastic force stored in the torsion coil spring 24 by connecting the intermediate member 40 and the terminal member 50 via the ball 22 when the main rotating member 30 and the intermediate member 40 are separated and unconnected. The release mechanism 20 is configured such that the intermediate member 40 and the terminal member 50 are connected when the rotation angle of the rotating portion 71 becomes greater than or equal to a first angle P1.

[0066] Figure 10 shows the state in which the main rotating member 30 has been further rotated in the first rotational direction R1 from the state shown in Figure 9. As the main rotating member 30 rotates relative to the end member 50, the connecting portion 53 of the end member 50 is in contact with the end of the first connecting hole 33 of the main rotating member 30. As shown in Figure 10, when the connecting portion 53 of the end member 50 is in contact with the end of the first connecting hole 33 of the main rotating member 30, further relative rotation of the main rotating member 30 is restricted.

[0067] When the main rotating member 30 is further rotated in the first rotation direction R1 from the state shown in Figure 10, the holding member 28 releases the holding of the end member 50, and the main rotating member 30 and the end member 50 rotate relative to the cylinder 61. At this time, because the intermediate member 40 is connected to the end member 50 via the ball 22, the main rotating member 30, the intermediate member 40 and the end member 50 rotate together relative to the cylinder 61. The release mechanism 20 is configured such that when the rotation angle of the rotating part 71 becomes a second angle P2 or greater, the main rotating member 30, the intermediate member 40 and the end member 50 rotate together relative to the cylinder 61.

[0068] In the first embodiment, the first connecting hole 33 of the main rotating member 30 corresponds to the "first engaging portion". The connecting portion 53 of the end member 50 corresponds to the "second engaging portion". The connecting portion 53 is columnar in shape and can engage with the first connecting hole 33, which is a hole. The connecting portion 53 and the first connecting hole 33 can engage with each other via the second connecting hole 43 of the intermediate member 40. Specifically, the portion of the connecting portion 53 that protrudes towards the main rotating member 30 through the second connecting hole 43 can engage with the first connecting hole 33. Therefore, the intermediate member 40 does not interfere with the engagement between the connecting portion 53 and the first connecting hole 33. In this specification, "engaged" means, for example, that two members are fixed together when one member comes into contact with the other member. The two engaged members are connected so as to rotate in conjunction in at least one direction.

[0069] Next, we will describe the case where the rotating part 71 rotates in the second rotation direction R2. When the main rotating member 30 is rotated in the second rotation direction R2 from the state shown in Figure 10, it reaches the state shown in Figure 9. When the main rotating member 30 is rotated in the second rotation direction R2 from the state shown in Figure 9, it reaches the state shown in Figure 8. The release mechanism 20 is such that when the ball housing portion 52 and the ball hole 42 are facing each other, if the ball 22 is not being pushed by the flat portion 30a of the main rotating member 30, the ball 22 will roll in the forward direction X1, i.e., toward the main rotating member 30. When the main rotating member 30 is rotated in the second rotation direction R2 from the state shown in Figure 10 through the state shown in Figure 9 to the state shown in Figure 8, the point of contact between the ball 22 on the main rotating member 30 moves from the flat portion 30a to the inclined portion 32a, and then further to the bottom portion 32b. When the ball 22 moves from the flat portion 30a to the ramp groove 32 in this way, the fixing of the ball 22 by the intermediate member 40 and the terminal member 50 is released. In other words, the connection between the intermediate member 40 and the terminal member 50 via the ball 22 is released. On the other hand, the main rotating member 30 and the intermediate member 40 are connected via the ball 22. The release mechanism 20 is configured such that when the rotation angle of the rotating part 71 becomes less than the first angle P1, the connection between the intermediate member 40 and the terminal member 50 is released. The release mechanism 20 is configured such that when the rotation angle of the rotating part 71 becomes less than the first angle P1, the main rotating member 30 and the intermediate member 40 are connected.

[0070] When the connection between the intermediate member 40 and the terminal member 50 via the ball 22 is released, the elastic force of the spring 24 is released. As a result, a force is applied to the rotating part 71 that rotates it in the second rotation direction R2 via the intermediate member 40 and the main rotating member 30 connected to the intermediate member 40.

[0071] When the main rotating member 30 and the intermediate member 40 rotate in the second rotation direction R2 from the state shown in Figure 8, the state shown in Figure 7 is reached. Here, in the transition from the state shown in Figure 8 to the state shown in Figure 7, the connecting portion 53 of the end member 50 transitions from a state in which it is in contact with one end of the second connecting hole 43 of the intermediate member 40 to a state in which it is in contact with the other end of the second connecting hole 43. As shown in Figure 7, when the connecting portion 53 is in contact with the rear end of the second connecting hole 43 of the intermediate member 40 in the second rotation direction R2, the intermediate member 40 and the end member 50 become one, and the elastic force stored in the spring 24 no longer acts on the main rotating member 30.

[0072] Figure 11 shows the state in which the main rotating member 30 has been further rotated in the second rotation direction R2 from the state shown in Figure 7. When the main rotating member 30 is rotated in the second rotation direction R2 from the state shown in Figure 7, the ball 22 can roll in the ramp groove 32. Therefore, the main rotating member 30 can rotate relative to the intermediate member 40 until the ball 22 contacts the ramp end 32c. In the state shown in Figure 11, the main rotating member 30 is rotating relative to the end member 50, so that the connecting portion 53 of the end member 50 is in contact with the end of the first connecting hole 33 of the main rotating member 30. As shown in Figure 11, when the connecting portion 53 of the end member 50 contacts the end of the first connecting hole 33 of the main rotating member 30, further relative rotation of the main rotating member 30 is restricted. When the main rotating member 30 is further rotated in the second rotation direction R2 from this state, the holding member 28 releases the holding of the end member 50, and the main rotating member 30 and the end member 50 rotate relative to the cylinder 61. At this time, the ball 22 is fixed by the ramp end 32c of the ramp groove 32 and the intermediate member 40. That is, the main rotating member 30 and the intermediate member 40 are connected via the ball 22. Therefore, the main rotating member 30, the intermediate member 40 and the end member 50 rotate together relative to the cylinder 61. The release mechanism 20 is configured such that when the rotation angle becomes less than or equal to the rear end position angle PX, the main rotating member 30, the intermediate member 40 and the end member 50 rotate together relative to the cylinder 61.

[0073] Furthermore, when rotating the main rotating member 30 in the first rotational direction R1 from the state shown in Figure 11, the main rotating member 30 and the intermediate member 40 remain connected until the state shown in Figure 7 is reached. Also, the elastic force stored in the spring 24 does not act on the main rotating member 30. Thus, the release mechanism 20 is configured such that when the rotation angle of the rotating part 71 is less than or equal to the operating angle PZ, the connecting part 53 of the terminal member 50 is in contact with the end of the second connecting hole 43 of the intermediate member 40, so that the elastic force stored in the spring 24 does not act on the main rotating member 30.

[0074] <Operation and Effects of the First Embodiment> Figure 12(a) shows the change in the rotation angle of the rotating part 71. In Figure 12(a), when the rotating part 71 is rotated in the first rotation direction R1, the rotation angle is displaced in the direction indicated by the positive sign. On the other hand, when the rotating part 71 is rotated in the second rotation direction R2, the rotation angle is displaced in the direction indicated by the negative sign.

[0075] Figure 12(b) shows the change in torque generated in the main rotating member 30 of the release mechanism 20 when the rotating part 71 is rotated according to the change in rotation angle shown in Figure 12(a). In Figure 12(b), the positive torque is the torque acting in the second rotational direction R2, i.e., the torque acting in the backward direction X2. On the other hand, the negative torque is the torque acting in the first rotational direction R1, i.e., the torque acting in the forward direction X1.

[0076] As shown in Figure 12(a), the rotation angle of the rotating part 71 is increased during the period up to timing t3. The rotation angle at timing t3 is smaller than the second angle P2.

[0077] When the rotating part 71, whose rotation angle is the rear end position angle PX, is rotated in the first rotation direction R1, the rotation angle becomes larger than the operating angle PZ at timing t1, and the elastic force of the spring 24 acts on the main rotating member 30. As the elastic force of the spring 24 acts on the main rotating member 30, a first torque Tq1 is generated as a torque applied in the second rotation direction R2, as shown in Figure 12(b). When the rotation angle is further increased while the elastic force of the spring 24 is acting on the main rotating member 30, elastic force is accumulated in the spring 24. The torque increases according to the repulsive force when elastic force is accumulated in the spring 24. When the spring 24 is filled to its maximum elastic force, the generated torque reaches the second torque Tq2. The difference between the first torque Tq1 and the second torque Tq2 represents the magnitude of the torque due to the elastic force accumulated in the spring 24.

[0078] When the rotation angle at timing t2 becomes greater than or equal to the first angle P1, the main rotating member 30 and the intermediate member 40 become disconnected, causing the torque to begin to decrease. Thereafter, as long as the rotation angle remains greater than or equal to the first angle P1, that is, as long as the energy storage unit U1 is disconnected from the rotating part 71, the stored elastic force is maintained.

[0079] When the rotation angle is changed between the first angle P1 and the second angle P2 while the main rotating member 30 and the intermediate member 40 are not connected, that is, between the state shown in Figure 9 and the state shown in Figure 10, the generated torque is the minimum torque Tqmin, as shown in Figure 12(b). The minimum torque Tqmin is equal to the magnitude of the lost torque generated in response to the sliding of the main rotating member 30 against the ball 22, for example, when the main rotating member 30 is not connected to either the intermediate member 40 or the terminal member 50. The lost torque refers to the magnitude of the torque mechanically lost in the torque transmission path of the release mechanism 20. The minimum torque Tqmin is extremely small compared to the first torque Tq1 and the second torque Tq2.

[0080] From timing t3 onward, the rotating part 71 begins to rotate in the second rotation direction R2. During the period from timing t4 to timing t5, when the rotation angle is within the range of less than the first angle P1 and greater than the operating angle PZ, a torque is generated in the second rotation direction R2 due to the release of the elastic force of the spring 24, as shown in Figure 12(b). Subsequently, the rotating part 71 is further rotated in the second rotation direction R2 beyond the operating angle PZ to the standby position angle PY.

[0081] In Figure 12, after the rotating part 71 is rotated to the standby position angle PY from timing t5 onwards, the rotating part 71 is rotated again in the first rotation direction R1 during the period until timing t9. At timing t6, the rotation angle becomes larger than the operating angle PZ, and at timing t7, the rotation angle becomes greater than or equal to the first angle P1. During the period from timing t6 to timing t7, the torque increases according to the repulsive force when the elastic force is stored in the spring 24, similar to the period from timing t1 to timing t2. Subsequently, the torque decreases as the main rotating member 30 and the intermediate member 40 become disconnected.

[0082] From timing t7 onward, after the rotation angle reaches the second angle P2 at timing t8, the rotation angle becomes larger than the second angle P2 at timing t9. When the rotating part 71 is further rotated in the first rotation direction R1 within the range where the rotation angle is greater than or equal to the second angle P2, the main rotating member 30, the intermediate member 40, and the terminal member 50 rotate together relative to the cylinder 61. Therefore, during periods when the rotation angle is increased within the range of greater than or equal to the second angle P2, such as from timing t8 to timing t9, a torque greater than the second torque Tq2 is generated, as shown in Figure 12(b).

[0083] From timing t9 onward, the rotating part 71 begins to rotate in the second rotation direction R2. During the period from timing t10 ​​to timing t11, when the rotation angle is within the range of less than the first angle P1 and greater than the operating angle PZ, torque is generated due to the release of the elastic force of the spring 24, as shown in Figure 12(b).

[0084] From timing t11 onward, after the rotation angle exceeds the operating angle PZ and reaches the standby position angle PY, the rotating part 71 is further rotated in the second rotation direction R2. Subsequently, at timing t12, after the rotation angle reaches the rear end position angle PX, the rotation of the rotating part 71 continues until timing t13. When attempting to rotate the rotating part 71 further in the second rotation direction R2 from the rear end position angle PX, the main rotating member 30, the intermediate member 40, and the terminal member 50 rotate together relative to the cylinder 61. Therefore, during the period from timing t12 to timing t13, a torque is generated in the first rotation direction R1, as shown in Figure 12(b).

[0085] The effects of this embodiment will now be explained. (1) Even if the power supply to the electric brake device 10 is lost during braking, the elastic force stored in the energy storage section U1 of the release mechanism 20 can apply torque to the rotating section 71 in a direction that reduces the braking force. This allows the remaining axial force to be released.

[0086] (2) In the release mechanism 20, the torsion coil spring 24 is preloaded. In addition to the preload, the switching unit U2 determines the connected and disconnected positions of the main rotating member 30 and the intermediate member 40, so that the target torque can be applied by the energy storage unit U1 at the target rotation angle.

[0087] (3) In the release mechanism 20, when the rotating part 71 is rotated in a direction that further increases the braking force after the elastic force has been stored, the rotating part 71 and the energy storage part U1 become disconnected. Therefore, even if the release mechanism 20 is provided in the torque transmission path of the electric brake device 10, deterioration of the kinetic energy transmission efficiency can be suppressed.

[0088] (4) The switching unit U2 as a ball lamp mechanism makes it possible to reduce the torque lost mechanically in response to operation. (5) When the rotating part 71 is further rotated in the first rotation direction R1 within the range where the rotation angle of the rotating part 71 is greater than or equal to the second angle P2, the main rotating member 30, the intermediate member 40 and the terminal member 50 rotate together relative to the cylinder 61. This adjusts the relative positions of the switching part U2 and the energy storage part U1 with respect to the cylinder 61 in the circumferential direction of the cylinder 61.

[0089] For example, as the brake friction material 12 wears down, the rotation angle at which the remaining axial force is maximum shifts from the first angle P1. Similarly, the rotation angle of the electric motor 63 at which the force with which the piston 62 presses the brake friction material 12 against the brake rotating body 11 is maximum also shifts from the second angle P2. In such cases, the operation of the switching part U2 in the release mechanism 20 may not occur at the expected rotation angle.

[0090] In this respect, according to this embodiment, the release mechanism 20 can be rotated relative to the cylinder 61 when the rotation angle is greater than or equal to the second angle P2. This allows adjustment of the relative positions of the switching section U2 and the energy storage section U1 with respect to the cylinder 61 in the circumferential direction. By adjusting the relative positions of the switching section U2 and the energy storage section U1, the second angle P2 can be adjusted. Therefore, the first angle P1 set for the release mechanism 20 can be made to match the rotation angle at which the remaining axial force is maximized when the brake friction material 12 is worn. This allows the release mechanism 20 to be operated with a desired setting regardless of changes due to the usage conditions of the electric braking device 10.

[0091] (6) The switching unit U2 switches whether or not the elastic force stored in the spring 24 acts on the main rotating member 30 at an operating angle PZ where the rotation angle of the rotating part 71 is less than the contact angle P0 and greater than the standby position angle PY. With this configuration, the release mechanism 20 can suppress drag by pulling the brake friction material 12 back in the backward direction X2 beyond the contact point between the brake friction material 12 and the brake rotating body 11. Furthermore, with this configuration, the piston 62 is not pulled back in the backward direction X2 beyond the standby position by the action of the energy storage unit U1. For this reason, it is not necessary to drive the electric motor 63 to keep the brake friction material 12 in the position corresponding to the standby position.

[0092] (Second Embodiment) The electric braking device 110 of the second embodiment will now be described. In the second embodiment, the configuration of the first and second engaging parts of the release mechanism differs from that of the first embodiment. In the second embodiment, components similar to those in the first embodiment are denoted by the same reference numerals. The following description will mainly focus on the components that differ from the first embodiment, while descriptions of components common to the first embodiment will be omitted as appropriate.

[0093] The release mechanism 120 of the electric brake device 110 comprises a driving rotating member 130, an intermediate member 140, and an end member 150. Similar to the first embodiment, the release mechanism 120 comprises a ball 22 and a torsion coil spring 24. Although not shown, the release mechanism 120 also comprises a holding member 28 and a regulating member 29, similar to the first embodiment.

[0094] As shown in Figure 13, the main rotating member 130 has a first protrusion 137 instead of the first connecting hole 33 in the first embodiment. The first protrusion 137 projects from the flat portion 30a toward the intermediate member 140.

[0095] The intermediate member 140 has a first recess 147 and a second protrusion 148 instead of the second connecting hole 43 in the first embodiment. The first recess 147 is formed on the surface of the intermediate member 140 facing the main rotating member 130. The first recess 147 is a non-penetrating groove. The shape of the first recess 147 when viewed in the axial direction is an arc shape. The second protrusion 148 is formed on the surface of the intermediate member 140 facing the end member 150. The second protrusion 148 projects toward the end member 150 from the surface of the intermediate member 140 facing the end member 150.

[0096] The terminal member 150 has a second recess 158 instead of the connecting portion 53 in the first embodiment. The second recess 158 is formed on the end wall 55 facing the intermediate member 40. The second recess 158 is a non-penetrating groove. The shape of the second recess 158 when viewed in the axial direction is an arc shape.

[0097] The states shown in Figures 13 to 17 correspond to the states shown in Figures 7 to 11 in the first embodiment, respectively. In the state shown in Figure 13, the first protrusion 137 of the main rotating member 130 is not in contact with either of the circumferential ends of the first recess 147 of the intermediate member 140.

[0098] In the state shown in Figure 13, the second protrusion 148 of the intermediate member 140 is in contact with one end of the second recess 158 of the terminal member 150. The intermediate member 140 is restricted from rotating relative to the terminal member 150 in the second rotational direction R2. That is, in the state shown in Figure 13, the elastic force of the spring 24 does not act on the main rotating member 130. When the main rotating member 130 is rotated in the first rotational direction R1 from the state shown in Figure 13, the state shown in Figure 14 is reached. As the intermediate member 140 rotates relative to the terminal member 150, the second protrusion 148 of the intermediate member 140 comes into contact with the other end of the second recess 158 of the terminal member 150, as shown in Figure 14. When the second protrusion 148 of the intermediate member 140 comes into contact with the other end of the second recess 158 of the terminal member 150, further rotation of the intermediate member 140 in the first rotational direction R1 is restricted. As the intermediate member 140 rotates relative to the terminal member 150 in this manner, elastic force is stored in the spring 24, similar to the first embodiment.

[0099] When the main rotating member 130 is further rotated in the first rotational direction R1 from the state shown in Figure 14, the state shown in Figure 15 is reached. Similar to the first embodiment, the ball ramp mechanism disconnects the main rotating member 130 from the intermediate member 140, while connecting the intermediate member 140 to the terminal member 150. This maintains the elastic force stored in the spring 24.

[0100] If the main rotating member 130 is further rotated in the first rotational direction R1 from the state shown in Figure 15, it reaches the state shown in Figure 16. As the main rotating member 130 rotates relative to the intermediate member 140, the first protrusion 137 of the main rotating member 130 contacts one end of the first recess 147 of the intermediate member 140, as shown in Figure 16. When the first protrusion 137 of the main rotating member 130 contacts one end of the first recess 147 of the intermediate member 140, further relative rotation of the main rotating member 130 is restricted.

[0101] When the main rotating member 130 is further rotated in the first rotational direction R1 from the state shown in Figure 16, the main rotating member 130 and the intermediate member 140 are connected by the first protrusion 137 and the first recess 147. In addition, the intermediate member 140 and the end member 150 are connected by the ball 22. In this embodiment, the intermediate member 140 and the end member 150 are further connected by the second protrusion 148 and the second recess 158. When the main rotating member 130 is further rotated in the first rotational direction R1 from the state shown in Figure 16, the main rotating member 130, the intermediate member 140 and the end member 150 rotate together relative to the cylinder 61.

[0102] In the release mechanism 120 of the second embodiment, when the rotation angle of the rotating part 71 is increased to a second angle P2 or greater than the first angle P1, the first convex part 137, which is the "first engaging part," and the first concave part 147, which is the "second engaging part," engage. This engagement connects the main rotating member 130 and the intermediate member 140, allowing the terminal member 150, which is connected to the intermediate member 140 by the ball 22, to rotate in accordance with the rotation of the rotating part 71.

[0103] From the state shown in Figure 16, rotating the main rotating member 130 in the second rotation direction R2 leads to the state shown in Figure 15. From the state shown in Figure 15, rotating the main rotating member 130 in the second rotation direction R2 leads to the state shown in Figure 14. Similar to the first embodiment, the ball ramp mechanism disconnects the intermediate member 140 and the terminal member 150 via the ball 22. This releases the elastic force of the spring 24. On the other hand, at this time the main rotating member 130 and the intermediate member 140 are connected via the ball 22. Therefore, a force that rotates the rotating part 71 in the second rotation direction R2 is applied to the rotating part 71 via the intermediate member 140 and the main rotating member 130 connected to the intermediate member 140.

[0104] When the main rotating member 130 and the intermediate member 140 rotate in the second rotational direction R2 from the state shown in Figure 14, the state shown in Figure 13 is reached. Figure 17 shows the state in which the main rotating member 130 has been further rotated in the second rotation direction R2 from the state shown in Figure 13. As the main rotating member 130 rotates relative to the end member 150, the first protrusion 137 of the main rotating member 130 is in contact with the other end of the first recess 147 of the intermediate member 140. As shown in Figure 17, when the first protrusion 137 of the main rotating member 130 is in contact with the other end of the first recess 147 of the intermediate member 140, further relative rotation of the main rotating member 130 is restricted. When the main rotating member 130 is further rotated in the second rotation direction R2 from the state shown in Figure 17, the main rotating member 130 and the intermediate member 140 are connected by the first protrusion 137 and the first recess 147. In addition, the intermediate member 140 and the end member 150 are connected by the second protrusion 148 and the second recess 158. When the main rotating member 130 is further rotated in the second rotation direction R2 from the state shown in Figure 17, the main rotating member 130, the intermediate member 140, and the terminal member 150 rotate together relative to the cylinder 61.

[0105] <Operation and Effects of the Second Embodiment> In the electric braking device 110 of the second embodiment, the connection configuration of the main rotating member 130, the intermediate member 140, and the terminal member 150 can be switched at the same rotation angle as in the electric braking device 10 of the first embodiment. That is, the operation of the energy storage unit U1 and the switching unit U2 in the second embodiment is the same as that of the energy storage unit U1 and the switching unit U2 in the first embodiment. The electric braking device 110 of the second embodiment has the same operation and effect as the electric braking device 10 of the first embodiment.

[0106] (Example of change) Each of the above embodiments can be implemented with the following modifications. Each embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0107] The linear motion conversion mechanism may have a screw shaft in the linear motion section. In this case, the rotating section is a nut with a screw hole. The main rotating members 30,130 may be molded integrally with the rotating part 71.

[0108] In the release mechanism 20, it is preferable that the flat portion 30a of the main rotating member 30 and the intermediate member 40 are not in contact in the axial direction, but they may be in contact. If the flat portion 30a and the intermediate member 40 are not in contact, the torque loss associated with the operation of the release mechanism 20 can be reduced. If the flat portion 30a of the main rotating member 30 and the intermediate member 40 are spaced apart, the spacing should be such that it does not hinder the movement of the ball 22 by the ball ramp mechanism. The spacing should also be such that it prevents the ball 22 from falling out by the ball ramp mechanism. The same applies to the space between the intermediate member 40 and the end wall 55 of the terminal member 50 in the axial direction.

[0109] The first arm portion 26 of the torsion coil spring 24 may be fixed to the member forming the cylinder 61 instead of being fixed to the end member 50. In this case as well, the same effects as those of (1) to (4) and (6) in the first embodiment can be obtained.

[0110] In the second embodiment, the terminal member 150 may be omitted. In this case, as in the above modified example, the first arm portion 26 of the torsion coil spring 24 may be fixed to the member forming the cylinder 61. Also, when the terminal member 150 is omitted, the ball hole of the intermediate member 140 is preferably a non-through hole.

[0111] The first and second engaging portions may have complementary shapes. For example, in the first embodiment, the main rotating member 30 may have a columnar engaging portion such as a connecting portion 53 instead of the first connecting hole 33, and the terminal member 50 may have an engaging portion such as the first connecting hole 33 instead of the connecting portion 53. Also, for example, in the second embodiment, the main rotating member 130 may have a recess as an engaging portion instead of the first protrusion 137, and the intermediate member 140 may have a protrusion as an engaging portion instead of the first recess 147.

[0112] • Within the scope that provides the same function as in each of the above embodiments, through holes as engaging parts may be replaced with non-through holes. For example, the first connecting hole 33 in the first embodiment may be a non-through hole. Similarly, non-through holes as engaging parts may be replaced with through holes. For example, the second recess 158 in the second embodiment may be a through hole.

[0113] The specific configurations that function as the energy storage unit U1 and the switching unit U2 are not limited to the configurations exemplified in each of the above embodiments. For example, in each of the above embodiments, a ball ramp mechanism was exemplified as the switching unit U2, but a friction clutch may be used instead of the ball ramp mechanism.

[0114] (Other technological ideas) This document describes the technical concepts that can be understood from the embodiments and modifications described herein. [A] An example of an electric braking system is: The system comprises a piston that moves in conjunction with the linear motion of the aforementioned linear motion unit, and a cylinder that houses the piston. The brake friction material can be moved by the piston, The main rotating member has a first engaging portion, The intermediate member has a shape complementary to the first engaging portion and has a second engaging portion that can engage with the first engaging portion. The terminal member is located inside the cylinder, When the rotation angle of the rotating part is increased to a second angle or greater than the first angle, the first engaging part and the second engaging part engage, and this engagement connects the main rotating member and the intermediate member, so that the end member connected to the intermediate member by the ball can rotate in accordance with the rotation of the rotating part. The main rotating member, the intermediate member, and the terminal member connected to the intermediate member by the ball rotate relative to the cylinder, thereby adjusting the relative positions of the switching unit and the energy storage unit with respect to the cylinder in the circumferential direction of the cylinder. [Explanation of Symbols]

[0115] 10…Electric braking device 11... Brake rotating body 12…Brake friction material 20...Release mechanism 22... Ball 24... Torsion coil spring 28…Retaining member 30… Main rotating member 30a...Flat area 32... Ramp groove 32a…Slope part 33...First connection hole (first engagement part) 40…Intermediate member 42...Ballhole 43…Second connection hole 50…End member 52...Ball storage compartment 53…Connecting section (second engaging section) 61...Cylinder 62... Piston 63… Electric motor 65…Transmission mechanism 70…Linear motion conversion mechanism 71... Rotating part 74…Linear motion section P1…first angle P2…Second angle R1...First rotation direction R2…Second rotation direction U1…Storage section U2...Switching section X1…Forward direction X2…Reverse direction

Claims

1. An electric braking device that is driven by an electric motor and includes a linear motion conversion mechanism that converts the rotational motion of a rotating part into linear motion of a linear motion part, and generates braking force on the wheel by pressing a brake friction material, which is linked to the linear motion of the linear motion part, against a brake rotating body that rotates integrally with the wheel, In the connected state, the energy storage unit deforms as the rotating part rotates in a direction that increases the braking force, thereby accumulating elastic force, and when the accumulated elastic force is released, the rotating part rotates in a direction that decreases the braking force, and in the unconnected state, separated from the rotating part, the energy storage unit holds the accumulated elastic force, The system includes a switching unit that, when the rotation angle of the rotating part is less than a first angle, connects the energy storage unit and the rotating part, and when the rotation angle of the rotating part is equal to or greater than the first angle, disconnects the energy storage unit and the rotating part. Electric braking device.

2. The aforementioned switching unit is a ball lamp mechanism, A main rotating member having a flat portion arranged in a plane perpendicular to the rotation axis of the rotating portion and a ramp groove formed in the flat portion, which rotates integrally with the rotating portion, The ball and, The main rotating member includes an intermediate member positioned opposite the surface having the ramp groove, and having a ball hole capable of accommodating the ball, The energy storage unit includes the intermediate member, The aforementioned switching unit is When the rotation angle of the rotating part is less than the first angle, the ball is positioned in the inclined portion of the ramp groove of the main rotating member and in the ball hole of the intermediate member, and the rotating part and the energy storage part are connected by connecting the main rotating member and the intermediate member via the ball, thereby bringing the rotating part and the energy storage part into the connected state. When the rotation angle of the rotating part is greater than or equal to the first angle, the ball pushed out by the inclined portion and the flat portion in the ramp groove of the main rotating member is located in the ball hole of the intermediate member, and by separating the intermediate member from the main rotating member, the rotating part and the energy storage part are made disconnected. The electric braking device according to claim 1.

3. The ball hole of the intermediate member is a through hole, The intermediate member is positioned on the opposite side from the main rotating member, and further comprises a terminal member having a ball housing portion facing the ball hole of the intermediate member, The switching section, which is a ball lamp mechanism, further includes the terminal member, The switching unit, when the rotation angle of the rotating unit is equal to or greater than the first angle, causes the balls pushed out by the inclined portion and the flat portion in the ramp groove of the main rotating member to be located in the ball hole of the intermediate member and the ball housing portion of the terminal member, thereby separating the intermediate member from the main rotating member and connecting the intermediate member to the terminal member via the balls, thereby disconnecting the rotating unit and the energy storage unit. The energy storage unit further includes the terminal member and a torsion coil spring, one end of which is fixed to the intermediate member and the other end of which is fixed to the terminal member. The energy storage unit, in a state where the main rotating member and the intermediate member are connected via the ball, stores the elastic force in the torsion coil spring by rotating the intermediate member connected to the main rotating member relative to the terminal member by rotating the rotating unit in a direction that increases the braking force. The energy storage unit maintains the elastic force stored in the torsion coil spring by connecting the intermediate member and the terminal member via the ball when the main rotating member and the intermediate member are separated. The electric braking device according to claim 2.

4. The system comprises a piston that moves in conjunction with the linear motion of the aforementioned linear motion unit and a cylinder that houses the piston, The brake friction material can be moved by the piston, The main rotating member has a first engaging portion, The terminal member is located inside the cylinder and has a second engaging portion that is complementary in shape to the first engaging portion and can engage with the first engaging portion. The intermediate member has a connecting hole which is a through hole, and the first engaging portion and the second engaging portion engage through the connecting hole, so that the intermediate member does not interfere with the engagement between the first engaging portion and the second engaging portion. When the rotation angle of the rotating part is increased to a second angle or greater than the first angle, the first engaging part and the second engaging part engage, and this engagement connects the driving rotating member and the end member, allowing the end member to rotate in accordance with the rotation of the rotating part. The main rotating member, the intermediate member connected to the end member by the ball, and the end member rotate relative to the cylinder, thereby adjusting the relative positions of the switching unit and the energy storage unit with respect to the cylinder in the circumferential direction of the cylinder. The electric braking device according to claim 3.

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