Electric brake device

Abstract

The invention relates to an electric brake device. In a braking force maintaining mechanism (70), when a ratchet gear (71) rotates in an increasing direction (X1) in a state in which a claw member (72) is engaged with the ratchet gear (71) that rotates in conjunction with driving of an electric motor, engagement between the ratchet gear (71) and the claw member (72) is released, and thus rotation of the ratchet gear (71) in a decreasing direction (X2) is permitted. In an engagement release mechanism (80), when a bolt (81) rotates in a first direction (Y1) due to an external input force, a release claw (86) approaches and comes into contact with a ratchet gear (71). When the bolt (81) rotates in the first direction (Y1) in this state, the ratchet gear (71) is rotated in the increasing direction (X1) by the release claw (86).

Description

Technical Field

[0001] This invention relates to an electric braking device installed in a vehicle. Background Technology

[0002] Patent Document 1 discloses an electric braking device equipped with a parking brake mechanism. The parking brake mechanism includes a rotating body that rotates in conjunction with an electric motor, which serves as the power source for the electric braking device, and an engaging portion that can move forward and backward in both the direction of approach to and separation from the rotating body. The direction of rotation of the rotating body when the braking force increases is defined as the "increasing direction," and the direction of rotation of the rotating body when the braking force decreases is defined as the "decreasing direction." In this case, the parking brake mechanism restricts the rotation of the rotating body in the decreasing direction by engaging the engaging portion with the rotating body. This maintains the state of generating braking force. On the other hand, when the rotating body rotates in the increasing direction while the engaging portion is engaged with the rotating body, the engagement between the engaging portion and the rotating body is released, thereby disengaging the engaging portion from the rotating body. This releases the state of generating braking force.

[0003] However, when the engaging part is engaged with the rotating body, sometimes an abnormality occurs, preventing the electric motor from driving. In this case, since the rotating body cannot rotate, the braking force cannot be released.

[0004] The caliper of the electric braking device in Patent Document 1 is provided with an insertion hole for inserting a special tool into the device. When the tool is inserted into the device through the insertion hole, the tip of the tool contacts the rotating body. With the tip of the tool in contact with the rotating body, the operator can rotate the rotating body in an increasing direction by pressing the tool deeper into the device. When the rotating body is rotated in the increasing direction by the tool, the engagement between the engaging part and the rotating body is released. As a result, the engaging part separates from the rotating body. Therefore, even if the electric motor cannot drive it, the state of generating braking force can be eliminated.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2010-58788

[0006] In cases where the rotating body is forcibly rotated by pressing a tool that has been in contact with the rotating body into the depth of the device, as described above, the operator needs to use very strong force to press the tool into the depth of the device. Summary of the Invention

[0007] An electric braking device for solving the above-mentioned problem is a device in which the rotational motion of a linear motion conversion mechanism is rotated according to the rotational motion of an electric motor, and the rotational motion of the rotational part is converted into the linear motion of the linear motion part of the linear motion conversion mechanism. Based on the linear motion of the linear motion part, braking force is generated on the wheel by adjusting the force applied to the friction material by a first rotating part that rotates integrally with the wheel of the vehicle. This electric braking device includes a braking force maintaining mechanism having a second rotating part and an engaging part. The second rotating part rotates in linkage with the drive of the electric motor. When the engaging part is engaged with the second rotating part, it restricts the rotation of the second rotating part in the decreasing direction and allows the rotation of the second rotating part in the increasing direction. The braking force maintaining mechanism is configured such that when the second rotating part rotates in the increasing direction while the engaging part is engaged with the second rotating part, it releases the engagement of the engaging part with the second rotating part, thereby allowing the second rotating part to rotate in the decreasing direction. The decreasing direction is the direction of rotation of the second rotating part when the braking force is reduced, and the increasing direction is the direction of rotation when the braking force is increased. The rotation direction of the second rotating part when the braking force increases; and the engagement release mechanism, which has a third rotating part and an actuating part, wherein the third rotating part rotates when an external force is input, and the actuating part approaches and contacts the second rotating part when the third rotating part rotates along a first direction, and when the third rotating part rotates along the opposite direction of the first direction, i.e., the second direction, the actuating part moves in a direction away from the second rotating part, and the engagement release mechanism is configured such that when the third rotating part rotates along the first direction with the actuating part in contact with the second rotating part, the external force is increased, and the actuating part causes the second rotating part to rotate along the increasing direction.

[0008] The aforementioned electric braking device has the following effect: when a force is input from the outside to the engagement release mechanism in order to release the state in which the reduction of braking force is restricted by the braking force maintaining mechanism, even if the force is relatively small, the state in which the reduction of braking force is restricted can be released. Attached Figure Description

[0009] Figure 1 This is a structural diagram showing the general contents of the electric braking device according to the embodiment.

[0010] Figure 2 This is a schematic cross-sectional view showing a portion of the electric braking device.

[0011] Figure 3 This is a cross-sectional view showing the parking brake device included in the electric braking system.

[0012] Figure 4 This is a cross-sectional view of the parking brake device.

[0013] Figure 5 This is a cross-sectional view of the parking brake device.

[0014] Figure 6 This is a schematic cross-sectional view of the portion of the base component that is engaged with the bolt in the engagement and disengagement mechanism of the parking brake device.

[0015] Figure 7 It is a schematic cross-sectional view showing the connection between the bolt and the release claw in the engagement and disengagement mechanism.

[0016] Figure 8 This is a schematic cross-sectional view showing the insertion of a tool into the electric braking device from the outside.

[0017] Figure 9 This is a perspective view showing the bolts in the engagement / disengagement mechanism of the modified example.

[0018] Figure 10 This is a perspective view showing the case where the front end of the bolt engages with the ratchet gear in the modified engagement / disengagement mechanism.

[0019] Figure 11 This is a cross-sectional view of a parking brake device with an altered engagement release mechanism. Detailed Implementation

[0020] The following is based on Figures 1 to 8 An embodiment of the electric braking device will be described.

[0021] <Overall Structure of Electric Braking System>

[0022] Figure 1 The diagram shows an electric braking device 20 mounted on a vehicle. The electric braking device 20 is a disc-type electric braking device. The electric braking device 20 includes a brake disc 21 that rotates integrally with the vehicle's wheels 11, a caliper 24 supported by the vehicle's body, and an MGU 25 connected to the caliper 24. The brake disc 21 corresponds to the "first rotating part." MGU stands for "motor generator unit."

[0023] The caliper 24 is supported on a brake pad 22 located on one side of the brake disc 21 and a brake pad 23 located on the other side of the brake disc 21, extending in the direction of the axle 12 which rotates integrally with the wheel 11. These brake pads 22 and 23 correspond to "friction materials". The electric braking device 20 generates braking force on the wheel 11 by pressing the two brake pads 22 and 23 against the brake disc 21.

[0024] The electric braking device 20 includes an electric motor 30 as a power source, a reduction mechanism 40, a linear motion conversion mechanism 50, a piston 55, and a parking brake device 60. The linear motion conversion mechanism 50 and the piston 55 are mounted on the caliper 24. The electric motor 30, the reduction mechanism 40, and the parking brake device 60 are mounted on the MGU 25.

[0025] The electric motor 30 has an output shaft 31 that can rotate in both forward and reverse directions.

[0026] The reduction mechanism 40 reduces the rotational motion of the output shaft 31 of the electric motor 30 and outputs it to the linear motion conversion mechanism 50. For example, the reduction mechanism 40 has multiple meshing gears. The multiple gears include an input gear 41 mounted on the output shaft 31 and an output gear 42 that outputs the rotational motion to the linear motion conversion mechanism 50. Hereinafter, the rotational motion of the output shaft 31 of the electric motor 30 will be simply referred to as the "rotational motion of the electric motor 30".

[0027] The linear motion conversion mechanism 50, for example, has a shaft member 51 that rotates integrally with the output gear 42, and a nut 52 coaxially configured with the shaft member 51. The base end of the shaft member 51 is fixed to the output gear 42. Furthermore, the shaft member 51 extends from its base end toward the brake pad 23. A screw portion 511 with external threads machined on its circumferential surface is provided on the shaft member 51. The inner circumferential surface of the nut 52 is internally threaded. The nut 52 is coaxially configured with the shaft member 51 and engages with the screw portion 511. Although in Figure 1 The details are omitted, but the linear motion conversion mechanism 50 has a rotation limiting part that restricts the rotation of the nut 52. Therefore, when the shaft member 51 rotates, the nut 52 moves linearly in a direction corresponding to the rotation direction of the shaft member 51. In other words, the shaft member 51 corresponds to the "rotating part of the linear motion conversion mechanism" that rotates according to the rotational motion of the electric motor 30. The nut 52 corresponds to the "linear motion part of the linear motion conversion mechanism". Furthermore, in this embodiment, the linear motion part and the rotating part are coaxially arranged.

[0028] Piston 55 is connected to nut 52. Therefore, when nut 52 moves linearly, piston 55 moves linearly in the same direction as the linear movement of nut 52. When piston 55 moves linearly towards brake disc 21, the force pressing the two brake pads 22 and 23 against brake disc 21 increases. On the other hand, when piston 55 moves linearly away from brake disc 21, the force pressing the two brake pads 22 and 23 against brake disc 21 decreases. In other words, the electric braking device 20 can adjust the force pressing the two brake pads 22 and 23 against brake disc 21 by the linear movement of piston 55.

[0029] Parking Braking System

[0030] Reference Figures 1 to 8 The structure of the parking brake device 60 will be described.

[0031] The parking brake device 60 is a device used to maintain the state of generating braking force even when the power supply to the electric motor 30 is stopped.

[0032] like Figure 2 as well as Figure 3 As shown, the parking brake device 60 includes a base component 61, a brake force maintaining mechanism 70, and an engagement / disengagement mechanism 80. The base component 61 is fixed to the MGU 25. Both the brake force maintaining mechanism 70 and the engagement / disengagement mechanism 80 are mounted on the base component 61. Since the MGU 25 is fixed to the caliper 24, the base component 61 can also be said to be fixed to the caliper 24 via the MGU 25.

[0033] <Brake Force Maintenance Mechanism>

[0034] The braking force maintaining mechanism 70 includes a ratchet gear 71, a pawl member 72, a first spring 73, and a solenoid 74. Multiple teeth 711 are arranged circumferentially on the outer peripheral surface of the ratchet gear 71. The ratchet gear 71 corresponds to a "second rotating part" that rotates in conjunction with the drive of the electric motor 30. In this example, the ratchet gear 71 is fixed to the output shaft 31 of the electric motor 30 in a rotatable manner.

[0035] Furthermore, the rotation direction of the output shaft 31 and ratchet gear 71 when the braking force is increased is defined as "increasing direction X1". The opposite direction of increasing direction X1 is defined as "decreasing direction X2". Decreasing direction X2 is also the rotation direction of the output shaft 31 and ratchet gear 71 when the braking force is decreased.

[0036] like Figure 3 as well as Figure 4 As shown, the pawl member 72 is configured to move forward and backward in both the direction of approaching and moving away from the ratchet gear 71. When the pawl member 72 approaches the ratchet gear 71, it engages with the teeth 711 of the ratchet gear 71. Thus, the rotation of the output shaft 31 and the ratchet gear 71 in the decreasing direction X2 is limited by the pawl member 72, thereby limiting the reduction of braking force. On the other hand, even when the pawl member 72 engages with the teeth 711, rotation of the output shaft 31 and the ratchet gear 71 in the increasing direction X1 is allowed, thus allowing an increase in braking force. Therefore, the pawl member 72 corresponds to an "engaging part" that, when engaged with the ratchet gear 71, restricts the rotation of the ratchet gear 71 in the decreasing direction X2, while allowing the ratchet gear 71 to rotate in the increasing direction X1.

[0037] The first spring 73 applies a force to the pawl member 72 in the direction of separation from the ratchet gear 71. Therefore, when the pawl member 72 is not engaged with the teeth 711 of the ratchet gear 71, the force of the first spring 73 causes the pawl member 72 to separate from the ratchet gear 71. On the other hand, when the pawl member 72 is engaged with the teeth 711 of the ratchet gear 71, even if a force is applied to the pawl member 72 from the first spring 73, the pawl member 72 remains engaged with the teeth 711.

[0038] The solenoid 74 is the power source for the claw component 72. In other words, when the solenoid 74 is energized, the claw component 72 moves in a direction close to the ratchet gear 71 due to the electromagnetic force generated by the solenoid 74, resisting the force of the first spring 73. Moreover, even if the energization to the solenoid 74 is stopped, the claw component 72 remains engaged with the teeth 711 when it is engaged with the teeth 711 of the ratchet gear 71.

[0039] <Card Release Mechanism>

[0040] like Figure 4 as well as Figure 5 As shown, the engagement / disengagement mechanism 80 includes a bolt 81, a second spring 85, and a release claw 86. The bolt 81 has a head 82 and a shaft 83. The circumferential surface of the shaft 83 is externally threaded. The bolt 81 is supported by a base member 61 in a rotatable state. Specifically, a through hole 61a extending axially along the bolt 81 is provided in the base member 61. The circumferential surface of the base member 61 forming the through hole 61a is internally threaded. Therefore, the bolt 81 engages with the base member 61. Furthermore, the head 82 is located on the side opposite to the position of the ratchet gear 71, separated from the base member 61.

[0041] The direction of rotation of the bolt 81 when the front end of the shaft 83 approaches the ratchet gear 71 is defined as "first direction Y1". The opposite direction of first direction Y1 is defined as "second direction Y2". Second direction Y2 is also the direction of rotation of the bolt 81 when the front end of the shaft 83 separates from the ratchet gear 71. In addition, the direction in which the shaft 83 moves linearly and separates from the base member 61 is defined as "advance direction Z1". The opposite direction of advance direction Z1 is defined as "retraction direction Z2". Retraction direction Z2 is the direction in which the front end of the shaft 83 approaches the base member 61 in the direction in which the shaft 83 moves linearly.

[0042] Here, as Figure 2 As shown, an insertion hole 25a is provided near the location of the engagement / disengagement mechanism 80 in the housing that forms the outline of the MGU25. The insertion hole 25a is normally sealed by a waterproof cover 26. Therefore, the interior of the MGU25, i.e., the interior of the housing, cannot be seen from the outside of the MGU25 through the insertion hole 25a. However, when... Figure 8 When the cover 26 is removed, a tool 100, such as a hex wrench, can be inserted into the MGU25 from the outside via the insertion hole 25a. Then, with the tool 100 already inserted into the MGU25 through the insertion hole 25a, the tip of the tool 100 can be engaged with the head 82 of the bolt 81. When the tool 100 is rotated with the bolt 81 engaged in this state, the bolt 81 rotates in the direction of rotation of the tool 100. In other words, the bolt 81 corresponds to a "third rotating part" that rotates when an external force is applied.

[0043] A second spring 85 is disposed between the head 82 of the bolt 81 and the base component 61. The second spring 85 applies force in the direction that causes the head 82 to separate from the base component 61. Figure 6 As shown, the portion of the shaft 83 to which external threads are machined is defined as "external thread tooth 831", and the portion of the base member 61 to which internal threads are machined is defined as "internal thread tooth 611". At this time, the external thread tooth 831 can be pressed against the internal thread tooth 611 by the force of the second spring 85. This increases the frictional force between the bolt 81 and the base member 61. As a result, the bolt 81 is difficult to rotate in either the first direction Y1 or the second direction Y2. Therefore, the rotation of the bolt 81 along the first direction Y1 is restricted when vibrations accompanying vehicle movement are transmitted to the engagement release mechanism 80. In other words, the second spring 85 corresponds to a "restriction part". This frictional force restricts the rotation of the bolt 81 along the first direction Y1 when vibrations accompanying vehicle movement are transmitted to the engagement release mechanism 80. Furthermore, this frictional force is very small compared to the force required to rotate the bolt 81. Therefore, this frictional force has a very small effect on the force required to rotate the bolt 81.

[0044] The release pawl 86 is connected to the shaft portion 83, allowing it to rotate relative to the shaft portion 83 of the bolt 81 and to move forward and backward in conjunction with the forward and backward movement of the bolt 81. Therefore, when the bolt 81 rotates along the first direction Y1, the release pawl 86 does not rotate but moves together with the shaft portion 83 in the advancing direction Z1. On the other hand, when the bolt 81 rotates along the second direction Y2, the release pawl 86 does not rotate but moves together with the shaft portion 83 in the withdrawing direction Z2. In other words, the release pawl 86 corresponds to the "operating part".

[0045] Reference Figure 7 An example of a portion of bolt 81 with release claw 86 will be described.

[0046] The release claw 86 has an annular supported portion 861. The shaft portion 83 of the bolt 81 passes through the inner side of the supported portion 861. A nut 87 is provided at the front end of the shaft portion 83 to prevent the supported portion 861 from disengaging from the bolt 81. In addition, an annular limiting member 88 is provided on the shaft portion 83 to restrict the supported portion 861 from approaching the head 82. The nut 87 and the limiting member 88 restrict the relative movement of the release claw 86 with respect to the shaft portion 83 along the axial direction of the shaft portion 83.

[0047] Alternatively, instead of providing the limiting component 88, the shaft diameter of the shaft portion 83 can be increased and a step difference can be provided in the shaft portion 83 to prevent the supported portion 861 from detaching from the bolt 81.

[0048] The supported portion 861 contacts, for example, the housing of the MGU25. Thus, when the bolt 81 rotates along the first direction Y1 and the second direction Y2, the supported portion 861 is restricted from rotating together with the bolt 81.

[0049] like Figure 3 as well as Figure 7 As shown, the release pawl 86 has a straight portion 862 and a pawl portion 863. The straight portion 862 is mounted on the supported portion 861. The straight portion 862 extends axially along the shaft portion 83 from the portion mounted on the supported portion 861. The pawl portion 863 is connected to the front end of the straight portion 862. The pawl portion 863 is configured to approach the rotation center of the ratchet gear 71 as it separates from the connection point with the straight portion 862 along the pushing direction Z1. Therefore, as... Figure 5 As shown, when the claw portion 863 engages with one of the teeth 711 of the ratchet gear 71, it is possible to prevent the teeth 711 adjacent to that tooth 711 in the decreasing direction X2 from contacting the release claw 86. That is, the claw portion 863 corresponds to a "claw portion" configured to engage with one of the teeth 711 of the multiple teeth 711.

[0050] <The function and effects of this implementation method>

[0051] When the braking force reduction is limited by the braking force maintaining mechanism 70, it is assumed that the electric motor 30 cannot be driven due to the occurrence of an abnormality.

[0052] In this case, such as Figure 8 As shown, the operator removes the cover 26 from the MGU25. In this state, the operator inserts a tool 100, such as a hex wrench, into the MGU25 through the insertion hole 25a provided in the housing of the MGU25. Then, the operator engages the tip of the tool 100 with the head 82 of the bolt 81.

[0053] The operator rotates tool 100, causing bolt 81 to rotate in the first direction Y1. This moves bolt 81 and release pawl 86 in the advancing direction Z1. Consequently, the pawl portion 863 of the release pawl 86 approaches ratchet gear 71. Finally, as... Figure 5 As shown, the pawl portion 863 engages with the teeth 711 of the ratchet gear 71. Even in this state, when the operator rotates the bolt 81 in the first direction Y1, the bolt 81 and the release pawl 86 move in the pushing direction Z1, thus the release pawl 86 pushes against the teeth 711. As a result, the ratchet gear 71 rotates in the increasing direction X1.

[0054] When the ratchet gear 71 rotates in the increasing direction X1, the engagement between the pawl member 72 and the ratchet gear 71 in the braking force maintaining mechanism 70 is released. Then, due to the force of the first spring 73, the pawl member 72 moves away from the ratchet gear 71. This allows the ratchet gear 71 to rotate in the decreasing direction X2, and releases the state where the reduction of braking force was restricted.

[0055] In the electric braking device 20, the force that rotates the ratchet gear 71 in the increasing direction X1 is not directly input to the ratchet gear 71. That is, the ratchet gear 71 is indirectly rotated in the increasing direction X1 by rotating the bolt 81. Therefore, compared with the conventional technology that directly rotates the ratchet gear 71 in the increasing direction X1, the ratchet gear 71 can be rotated in the increasing direction X1 even if the force input from the outside to the engagement release mechanism 80 is smaller.

[0056] In detail, the input that rotates the head 82 along the first direction Y1 is set as "F1", the distance from the rotation center of the bolt 81 to F1 is set as "r", the spacing of the teeth 611 of the external thread is set as "L", and the force that rotates the ratchet gear 71 along the increasing direction X1 is set as "F2". In this case, according to the work done when the bolt 81 rotates one revolution (Equation 1), since "2πr >> L" generally holds, "F1 << F2" holds.

[0057] 2·π·r×F1=L×F2···(Formula 1)

[0058] Therefore, when the electric braking device 20 inputs force from the outside to the engagement release mechanism 80 in order to release the state in which the reduction of braking force is restricted by the braking force holding mechanism 70, even if the force is relatively small, it can release the state in which the reduction of braking force is restricted.

[0059] Generally, the electric brake device 20 is equipped with a mechanism for rotating the output shaft 31 of the electric motor 30 in the decreasing direction X2 when the drive of the electric motor 30 stops. An example of such a mechanism is disclosed in Japanese Patent Application Publication No. 2017-7569.

[0060] Therefore, when the operator rotates the bolt 81 in the second direction Y2, the bolt 81 and the release pawl 86 move in the withdrawal direction Z2. As a result, the engagement between the release pawl 86 and the ratchet gear 71 is released. Consequently, the ratchet gear 71 and the output shaft 31 of the electric motor 30 rotate in the reduction direction X2. This reduces the braking force.

[0061] In this embodiment, the following effects can also be achieved.

[0062] (1) The release pawl 86 is configured to avoid contact with the tooth 711 adjacent to that tooth 711 in the decreasing direction X2 when the pawl part 863 is engaged with one of the teeth 711 of the ratchet gear 71. Thus, when attempting to rotate the bolt 81 in the first direction Y1 and thus rotate the ratchet gear 71 in the increasing direction X1, the state in which the pawl part 72 is engaged with the tooth 711 can be maintained.

[0063] (2) A braking force maintaining mechanism 70 and an engagement / disengagement mechanism 80 are installed on the base component 61. The braking force maintaining mechanism 70 and the engagement / disengagement mechanism 80 can be modularized.

[0064] When the braking force maintaining mechanism 70 and the engagement / disengagement mechanism 80 are not modularized, the braking force maintaining mechanism 70 and the engagement / disengagement mechanism 80 need to be assembled separately for the MGU25 during the assembly of the electric braking device 20.

[0065] In contrast, in this embodiment, since the braking force maintaining mechanism 70 and the engagement / disengagement mechanism 80 are modularized, the assembly time of the electric braking device 20 can be reduced.

[0066] (3) In the engagement / disengagement mechanism 80 of the electric brake device 20, the second spring 85 restricts the bolt 81 from rotating in the first direction Y1. Therefore, even if vibrations accompanying vehicle movement act on the engagement / disengagement mechanism 80, the bolt 81 is unlikely to rotate in the first direction Y1 due to the vibrations acting on the engagement / disengagement mechanism 80. Thus, the electric brake device 20 can prevent the release pawl 86 from unnecessarily engaging with the teeth 711 of the ratchet gear 71. However, if force is applied to the bolt 81 from the outside using the tool 100, the bolt 81 can rotate in the first direction Y1 and the second direction Y2.

[0067] (4) In the electric braking device 20, the bolt 81 functions as the third rotating part of the engagement release mechanism 80. By using a readily available bolt as the bolt 81, a common tool can be used as the tool 100 for rotating the bolt 81.

[0068] <Example of Change>

[0069] The above embodiments can be modified and implemented as follows. The above embodiments and the following modifications can be combined and implemented with each other to the extent that they are not technically contradictory.

[0070] In the engagement / disengagement mechanism 80, the bolt 81, which functions as a third rotating part, and the release pawl 86, which functions as an actuating part, are independent of each other, but are not limited to this. For example, the component that functions as a third rotating part may also function as an actuating part. For example, by setting... Figure 9 The bolt 81A shown can also function as a third rotating part, and can also function as an actuating part.

[0071] For example, such as Figure 9 as well as Figure 10 As shown, a recess 84A with an opening on its front end face is provided at the front end 84A of the shaft portion 83A of the bolt 81A. Thus, the front end 84A of the shaft portion 83A can function as an actuating part. In this case, even when the bolt 81 rotates along the first direction Y1, the front end 84A, which functions as an actuating part, can maintain its engagement with the teeth 711 of the ratchet gear 71.

[0072] Furthermore, an annular groove 83Aa extending circumferentially is formed on the side closer to the base end than the front end 84A. Thus, when the front end 84A engages with one of the teeth 711 of the ratchet gear 71, the shaft portion 83A is prevented from contacting the tooth 711 adjacent to that tooth 711 in the decreasing direction X2.

[0073] The engagement release mechanism 80 can also replace the second spring 85 with a spring that applies force to the head 82 in the direction that brings the head 82 of the bolt 81 closer to the base member 61. In this case, the spring functions as a limiting part of the engagement release mechanism 80.

[0074] If the rotation of bolt 81 along the first direction Y1 can be limited when vibrations from vehicle movement are transmitted to the engagement / disengagement mechanism, then a spring may not be required in the engagement / disengagement mechanism. For example, relative rotation of bolt 81 relative to base member 61 can be suppressed by adhesive or the like. In this case, the adhesive functions as a limiting element.

[0075] • If the bolt 81 can be restricted from rotating in the first direction Y1 when the vibration of the vehicle is transmitted to the engagement release mechanism, then the limiting part of the engagement release mechanism may not restrict the bolt 81 from rotating in the second direction Y2.

[0076] • If the bolt 81 does not rotate in the first direction Y1 even when the vibrations accompanying the vehicle's movement are transmitted to the engagement release mechanism, then the engagement release mechanism may not have a limiting part.

[0077] • Alternatively, the engagement release mechanism and braking force maintenance mechanism may not be modularized.

[0078] • As a mechanism for releasing the card, it can also be adopted Figure 11 The engagement release mechanism 80B is shown. The engagement release mechanism 80B is positioned on the opposite side from the engagement release mechanism 80 described in the above embodiment, separated by the braking force maintaining mechanism 70. The engagement release mechanism 80B includes a bolt 81B as an example of a third rotating part and a release pawl 86B as an example of an actuating part. The bolt 81B can rotate in both a first direction and a second direction by an external force. In the engagement release mechanism 80B, the first direction is the rotational direction for moving the bolt 81B and the release pawl 86B in the withdrawal direction Z2. The second direction is the rotational direction for moving the bolt 81B and the release pawl 86B in the advance direction Z1.

[0079] In the engagement release mechanism 80B, when the bolt 81B rotates in the first direction, the bolt 81B and the release pawl 86B move in the withdrawal direction Z2, thereby engaging the release pawl 86B with the teeth 711 of the ratchet gear 71. When the bolt 81B is rotated in the first direction in this state, the ratchet gear 71 rotates in the increasing direction X1 by the release pawl 86B. As a result, the engagement between the ratchet gear 71 and the pawl member 72 is released.

[0080] The engagement / disengagement mechanism can also have a rotating body, different from the bolt, as a third rotating part. For example, the engagement / disengagement mechanism can also be a structure that includes a cam that rotates under external force and a shaft that moves forward and backward according to the rotation of the cam. With this structure, when the diameter of the cam's rotating shaft is larger than the distance between the rotation center and the shaft contact portion, the force input to the cam from the outside can be increased. In this case, the shape of the front end of the shaft can be machined so that the front end of the shaft functions as an actuating part. Alternatively, an actuating part can be mounted on the shaft. In the above-described engagement / disengagement mechanism, the cam functions as the third rotating part.

[0081] The braking force maintaining mechanism may also have a different structure than the braking force maintaining mechanism 70 described in the above embodiments. For example, the braking force maintaining mechanism may be a locking device as described in Japanese Patent Application Publication No. 2023-28816. In this case, the second rotating part of the braking force maintaining mechanism may not be a gear.

[0082] If the second rotating part of the braking force maintaining mechanism is a component that rotates according to the drive of the electric motor 30, it can also be mounted on other components other than the output shaft 31 of the electric motor 30 in a state that allows it to rotate as an integral part. For example, the second rotating body can also be mounted on the shaft component 51 of the linear motion conversion mechanism 50.

[0083] • As a linear motion conversion mechanism, a nut can also function as a rotating part, and a shaft component can function as a linear motion part.

[0084] • Electric braking devices can also be drum-type devices. In this case, the brake drum functions as the first rotating part, and the brake shoes function as the friction material.

[0085] Other Technological Ideas

[0086] The technical ideas that can be grasped based on the above implementation methods and variations are recorded.

[0087] (Note 1) Preferably, the third rotating part of the above-mentioned engagement release mechanism is a bolt that moves forward and backward in accompaniment to rotation in the first direction and the second direction.

[0088] The aforementioned actuating part is connected to the bolt, enabling the actuating part to rotate relative to the bolt and to move forward and backward in conjunction with the forward and backward movement of the bolt.

[0089] (Note 2) Preferably, the limiting part of the above-mentioned engagement release mechanism is a spring that applies a force to the bolt in one of the directions of the bolt's forward and backward movement.

Claims

1. An electric braking device, wherein the rotational motion of a linear motion conversion mechanism is converted into linear motion of the linear motion conversion mechanism based on the rotational motion of an electric motor, and braking force is generated on the wheel by adjusting the force of a first rotating part that rotates integrally with the wheel of the vehicle based on the linear motion of the linear motion conversion mechanism, characterized in that, have: A braking force maintaining mechanism includes a second rotating portion and an engaging portion. The second rotating portion rotates in conjunction with the drive of an electric motor. When engaged with the second rotating portion, the engaging portion restricts rotation of the second rotating portion in a decreasing direction and allows rotation of the second rotating portion in an increasing direction. The braking force maintaining mechanism is configured such that when the second rotating portion rotates in the increasing direction while the engaging portion is engaged with the second rotating portion, rotation of the second rotating portion in the decreasing direction is allowed by releasing the engaging portion from the second rotating portion. The decreasing direction is the direction of rotation of the second rotating portion when the braking force is reduced, and the increasing direction is the direction of rotation of the second rotating portion when the braking force is increased. The engagement / disengagement mechanism has a third rotating part and an actuating part. The third rotating part rotates when an external force is input. The actuating part approaches and contacts the second rotating part when the third rotating part rotates in a first direction. When the third rotating part rotates in the opposite direction of the first direction, i.e., the second direction, the actuating part moves away from the second rotating part. The engagement / disengagement mechanism is configured such that when the third rotating part rotates in the first direction with the actuating part in contact with the second rotating part, the external force is increased, and the actuating part causes the second rotating part to rotate in the increased direction.

2. The electric braking device according to claim 1, characterized in that, The aforementioned second rotating part is a gear having multiple teeth arranged circumferentially. The aforementioned functional part is provided with a claw portion, which is configured to engage with one of the plurality of teeth of the aforementioned gear. The aforementioned functional part is configured to avoid contact with the tooth adjacent to that tooth in the aforementioned reducing direction when the aforementioned claw part engages with one of the aforementioned plurality of teeth.

3. The electric braking device according to claim 1, characterized in that, A base component equipped with the aforementioned braking force maintaining mechanism. The aforementioned engagement / disengagement mechanism is installed on the aforementioned base component.

4. The electric braking device according to any one of claims 1 to 3, characterized in that, The aforementioned engagement / disengagement mechanism is provided with a limiting part, which limits the rotation of the third rotating part along the first direction due to vibrations acting on the engagement / disengagement mechanism.

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