Electric brake device

Abstract

The invention relates to an electric brake device. A biasing member (56) for biasing the rotating part (52) from the direct-acting part (54) side to the transmission mechanism (36) side is disposed between the direct-acting part (54) and the transmission mechanism (36) in the direction of the rotation axis of the rotating part (52), and the biasing member (56) has a first engagement part that engages with the rotating part (52), and a second engagement part that engages with the housing (14) further toward the transmission mechanism (36) side than the first engagement part.

Description

Technical Field

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

[0002] As a prior art of an electric disc brake, there is a technique disclosed in Patent Document 1. The structure of the electric disc brake according to this prior art is briefly described as follows.

[0003] An outer shell is provided inside the cylindrical cylinder portion of the caliper, and the outer shell accommodates the flange portion of the rotating body (referred to as the driving spindle in Patent Document 1) in the direct-acting conversion mechanism (referred to as the thrust generating mechanism in Patent Document 1). An elastic component that applies force to the rotating body toward the opposite side of the claw portion of the caliper (the other axial side) is provided between the inner wall surface of the outer shell and the flange portion of the rotating body. The elastic component is pressed against the flange portion of the rotating body from one axial side by its elastic force. As a result, the rotating body is held in a state of being unable to move axially relative to the caliper by the force of the elastic component, thereby suppressing the axial displacement of the rotating body caused by the vibration of the wheel, and improving the vibration resistance of the direct-acting conversion mechanism.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2010-265971

[0005] In Patent Document 1, the elastic member applies force to the flange portion of the rotating body from the friction member side to the transmission mechanism side, but the elastic member is supported by an outer housing whose bottom surface is provided on the friction member side. Therefore, since the bottom surface of the outer housing supporting the elastic member needs to be arranged on the direct-acting conversion mechanism side, the degree of freedom in arrangement of the direct-acting conversion mechanism is reduced. Summary of the invention

[0006] In view of this, an object of one aspect of the present invention is to increase the degree of freedom in arrangement of a linear motion conversion mechanism and to improve vibration resistance.

[0007] In order to solve the above-mentioned problems, an electric brake device involved in one embodiment of the present invention transmits the rotation of an electric motor to a direct-acting conversion mechanism through a transmission mechanism, and in the direct-acting conversion mechanism, the rotational motion transmitted by the transmission mechanism is converted from the rotational motion of the rotating part to the linear motion of the direct-acting part, and the friction component linked to the linear motion of the direct-acting part is pressed against a rotating body rotating together with the wheel to generate a braking force on the wheel, wherein the electric brake device comprises: a housing that accommodates the direct-acting conversion mechanism arranged between the friction component and the transmission mechanism in the direction of the rotation axis of the rotating part; and a force-applying component that is arranged between the direct-acting part and the transmission mechanism in the direction of the rotation axis, and has a first engaging portion engaged with the rotating part, and a second engaging portion engaged with the housing on the transmission mechanism side closer to the first engaging portion, and the force-applying component applies force to the rotating part from the direct-acting part side to the transmission mechanism side.

[0008] According to one aspect of the present invention, the degree of freedom in arrangement of the linear motion conversion mechanism can be increased, and the vibration resistance can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic cross-sectional view of an electric disk brake according to an embodiment of the present invention.

[0010] Figure 2 yes Figure 1 An enlarged cross-sectional view of a main portion of an electric disc brake is shown.

[0011] Figure 3 It is along Figure 2 An enlarged cross-sectional view of line III-III in FIG.

[0012] Figure 4 yes Figure 2 An enlarged cross-sectional view of IV.

[0013] Figure 5 This is an enlarged cross-sectional view for explaining another method of joining the peripheral edge portion of the through hole of the leaf spring and the main shaft.

[0014] Figure 6 This is an enlarged cross-sectional view for explaining another method of joining the peripheral edge portion of the through hole of the leaf spring and the main shaft. DETAILED DESCRIPTION

[0015] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, in the specification and the claims, the rotation axis direction refers to the rotation axis direction of the rotating part. One side of the rotation axis direction refers to the direction toward the outside of the vehicle in the rotation axis direction. The other side of the rotation axis direction refers to the direction toward the inside of the vehicle in the axis direction. In the accompanying drawings, "AD" refers to the rotation axis direction, "ADo" refers to one side of the rotation axis direction, and "ADi" refers to the other side of the rotation axis direction.

[0016] Reference Figures 1 to 6 , an embodiment of the present invention is described. Figure 1 It is a schematic cross-sectional view of an electric disk brake according to an embodiment of the present invention. Figure 2 yes Figure 1 An enlarged cross-sectional view of a main portion of an electric disc brake is shown. Figure 3 It is along Figure 2 An enlarged cross-sectional view of line III-III in FIG. Figure 4 yes Figure 2 An enlarged cross-sectional view of IV. Figure 5 as well as Figure 6 This is an enlarged cross-sectional view for explaining another method of joining the peripheral edge portion of the through hole of the leaf spring and the main shaft.

[0017] (Electric brake device 10, caliper housing 14)

[0018] like Figure 1 As shown, the electric brake device 10 according to the embodiment is an electric disc brake for braking the wheels of a vehicle. The electric brake device 10 includes a caliper housing 14 (equivalent to the housing in the claims) arranged to span the peripheral portion of the rotating body 12 from both sides in the rotation axis direction of the rotating body 12. The rotating body 12 rotates integrally with the vehicle H.

[0019] (claw portion 16, cylinder portion 18)

[0020] like Figure 1 As shown, the caliper housing 14 is supported by a bracket (not shown) as a non-rotating member provided near the rotating body 12 so as to be movable in the direction of the rotation axis. The caliper housing 14 has a claw portion 16 on one side in the direction of the rotation axis, and the claw portion 16 protrudes in a direction orthogonal to the direction of the rotation axis. The caliper housing 14 has a cylindrical cylinder portion 18 on the other side in the direction of the rotation axis, and the cylinder portion 18 opens toward one side in the direction of the rotation axis.

[0021] (Outer friction member 20, inner friction member 22)

[0022] like Figure 1As shown, the electric brake device 10 includes two friction members 20 and 22 disposed between the claw portion 16 and the cylinder portion 18 of the caliper housing 14, and the two friction members 20 and 22 are supported by a bracket so as to be movable in the direction of the rotation axis. The outer friction member 20 located on one side of the rotation axis direction of the two friction members 20 and 22 presses one side of the rotating body 12. The outer friction member 20 is in sliding contact with one side of the rotating body 12 while pressing one side of the rotating body 12. The inner friction member 22 located on the other side of the rotation axis direction of the two friction members 20 and 22 presses the other side of the rotating body 12. The inner friction member 22 is in sliding contact with the other side of the rotating body 12 while pressing the other side of the rotating body 12.

[0023] (Piston 24)

[0024] like Figure 1 as well as Figure 2 As shown, a bottomed cylindrical piston 24 is provided in the cylinder portion 18 of the caliper housing 14 so as to be movable in the rotation axis direction and to press the inner friction member 22 toward the claw portion side (one side in the rotation axis direction). The other side in the rotation axis direction of the piston 24 is open. The piston 24 is configured to be non-rotatable relative to the cylinder portion 18 of the caliper housing 14 by a stop bolt (not shown) fixed to the cylinder portion 18 of the caliper housing 14. In addition, a circumferential groove 18g is formed on the inner peripheral surface of the cylinder portion 18. A piston seal 26 is embedded and provided in the circumferential groove 24g of the cylinder portion 18, and the piston seal 26 is in sliding contact with the outer peripheral surface of the piston 24.

[0025] (Motor Gear Unit 28, Unit Case 30, Electric Motor 32, Transmission Mechanism 36)

[0026] like Figure 1 as well as Figure 2 As shown, a motor gear unit 28 for driving the electric brake device 10 is provided on the side of the cylinder body 18 of the caliper housing 14. The motor gear unit 28 includes a unit housing 30 provided on the side of the cylinder body 18 of the caliper housing 14, an electric motor 32 provided in the unit housing 30, and a transmission mechanism 36 connected to an output shaft 34 of the electric motor 32 and amplifying the rotational torque of the electric motor.

[0027] (driving gear 38, intermediate large gear 42, intermediate small gear 44, driven gear 48)

[0028] like Figure 2As shown, the transmission mechanism 36 includes a driving gear 38 integrally provided on the output shaft 34 of the electric motor 32, and an intermediate large gear 42 rotatably provided in the unit housing 30 via a gear shaft 40. The intermediate large gear 42 meshes with the driving gear 38, and the outer diameter of the intermediate large gear 42 is larger than the outer diameter of the driving gear 38. The transmission mechanism 36 includes an intermediate pinion 44 coaxially integrally provided on the intermediate large gear 42, and a driven gear 48 rotatably provided in the unit housing 30 via a radial bearing 46. The outer diameter of the intermediate pinion 44 is smaller than the outer diameter of the intermediate large gear 42. The driven gear 48 meshes with the intermediate pinion 44, and the outer diameter of the driven gear 48 is larger than the outer diameter of the intermediate pinion 44. An inner spline portion 48s is formed in the central portion of the driven gear 48.

[0029] (Direct Motion Conversion Mechanism 50, Rotating Unit 52)

[0030] like Figure 2 As shown, a direct motion conversion mechanism 50 for converting the rotational motion transmitted from the transmission mechanism 36 into a direct motion is provided in the cylinder portion 18 of the caliper housing 14. In other words, a cylindrical cylinder portion 18 for accommodating the direct motion conversion mechanism 50 is arranged between the inner friction member 22 and the transmission mechanism 36 in the rotation axis direction. The direct motion conversion mechanism 50 has a rotating portion 52 that rotates by the rotational motion transmitted from the transmission mechanism 36. The rotating portion 52 extends in the rotation axis direction, and an outer spline portion 52s that spline-fits with the inner spline portion 48s of the driven gear 48 is formed on the outer peripheral surface of the rotating portion 52 at a position on the other side in the rotation axis direction. The rotating portion 52 is connected to the driven gear 48 by the outer spline portion 52s of the rotating portion 52 being spline-fitted with the inner spline portion 48s of the driven gear 48. An outer thread portion 52m is formed on the outer peripheral surface of the rotating portion 52 at a position on one side in the rotation axis direction, and the outer diameter of the outer thread portion 52m is larger than the outer diameter of the outer spline portion 52s. A concave portion 52g extending in the circumferential direction is formed near the external spline portion 52s on the outer peripheral portion of the cylindrical rotating shaft portion (a portion between the external thread portion 52m and the external spline portion 52s) concentric with the axis of the rotating portion 52.

[0031] (Direct motion portion 54)

[0032] like Figure 2 As shown, the direct-acting conversion mechanism 50 has a direct-acting portion 54 that directly moves along the rotation axis direction in conjunction with the rotation of the rotating portion 52. The direct-acting portion 54 is threadedly engaged with the external thread portion 52m of the rotating portion 52 and is located on the inner side of the piston 24. The direct-acting portion 54 is formed with an internal thread portion 54f that is threadedly engaged with the external thread portion 52m of the rotating portion 52.

[0033] (Leaf Spring 56)

[0034] like Figures 2 to 4As shown, at the end portion on the other side of the rotation axis direction on the cylinder body portion 18 of the caliper housing 14, a strip-shaped leaf spring 56 is arranged as a force-applying member for applying force to the rotating portion 52 from the direct-acting portion 54 side to the transmission mechanism 36 side. In other words, a strip-shaped leaf spring 56 is arranged between the direct-acting portion 54 and the transmission mechanism 36 in the rotation axis direction. The leaf spring 56 applies pressure to the rotating portion 52 by applying force to the rotating portion 52 toward the transmission mechanism 36 side. In addition, a through hole 56h for inserting the rotating portion 52 is formed in the middle portion of the leaf spring 56, and the inner diameter of the through hole 56h is smaller than the outer diameter of the external spline portion 52s of the rotating portion 52 and the vicinity thereof. In addition, the shape of the leaf spring 56 is not limited to a strip shape.

[0035] The peripheral edge portion of the through hole 56h of the leaf spring 56 is a first engagement portion engaged with 52g of the rotating portion 52. The peripheral edge portion of the through hole 56 of the leaf spring 56 can rotate relative to 52g of the rotating portion 52 and cannot move relative to it. The two end portions 56e of the leaf spring 56 are second engagement portions engaged with the cylinder body portion 18 on the transmission mechanism 36 side of the peripheral edge portion of the through hole 56h of the leaf spring 56 as the first engagement portion. The leaf spring 56 is bent and formed so that the middle portion of the leaf spring 56 protrudes to one side in the direction of the rotation axis. In other words, the leaf spring 56 is bent and formed so that the two end portions 56e of the leaf spring 56 are located on the transmission mechanism 36 side of the peripheral edge portion of the through hole 56h of the leaf spring 56. The peripheral edge portion of the through hole 56h of the leaf spring 56 may be indirectly engaged with the cylinder body portion 18 via other components instead of being directly engaged with the circumferential groove 52g of the rotating portion 52.

[0036] The end portion on the other side in the direction of the rotation axis of the cylinder body 18 is recessed toward one side in the direction of the rotation axis to form two recessed portions 18d that are respectively engaged with the two end portions 56e of the leaf spring 56. In other words, by engaging the two end portions 56e of the leaf spring 56 with the two recessed portions 18d of the cylinder body 18, the two end portions 56e of the leaf spring 56, which serve as the second engagement portion, are prevented from rotating relative to the cylinder body 18. In addition, the two end portions 56e of the leaf spring 56 are sandwiched by the cylinder body 18 of the caliper case 14 and the unit case 30 in a state of engaging with the two recessed portions 18d of the cylinder body 18.

[0037] like Figure 5 As shown in FIG. 1 , the peripheral edge portion of the through hole 56h of the leaf spring 56 may be engaged with the circumferential groove 52g of the rotating portion 52 via a plurality of balls 58 as a sliding member. In this case, the plurality of balls 58 are configured so as not to be separated from the circumferential groove 52g of the rotating portion 52. In addition, the sliding member is not limited to the balls 58, and any member that enhances lubrication such as grease may be used.

[0038] In the outer peripheral portion of the rotating shaft portion of the rotating portion 52, the circumferential groove 52g may be replaced with a Figure 6As shown in FIG. 1 , an annular protrusion 52b is formed as a convex portion extending in the circumferential direction. Furthermore, the peripheral edge portion of the through hole 56h of the leaf spring 56 may be joined to the protrusion 52b of the rotating portion 52. In this case, the inner diameter of the through hole 56h of the leaf spring 56 is smaller than the outer diameter of the protrusion 52b of the rotating portion 52. Instead of forming the annular protrusion 52b near the external spline portion 52s on the rotating portion 52, a plurality of protrusions may be formed at intervals in the circumferential direction.

[0039] (Load sensor 62, transmission member 66)

[0040] like Figure 1 as well as Figure 2 As shown in FIG. 1 , a load sensor 62 is provided inside the cylinder 18 of the caliper housing 14 to detect the pressing load of the inner friction member 22 as a friction member on the rotating body 12. In other words, the load sensor 62 is provided between the linear motion portion 54 and the leaf spring 56 in the direction of the rotation axis. Figure 3 As shown, when viewed from the inner side of the cylinder portion 18 of the caliper housing 14, the sensor connecting portion 64 of the load sensor 62 is located at a position separated from the leaf spring 56. In addition, even when the leaf spring 56 has a shape other than a strip shape, when viewed from the inner side of the cylinder portion 18 of the caliper housing 14, the sensor connecting portion 64 is located at a position separated from the leaf spring 56.

[0041] like Figure 1 as well as Figure 2 As shown, an annular transmission member 66 is provided between the middle portion of the rotating portion 52 and the load sensor 62 via a thrust bearing 68 and a washer 70 to transmit a force from the rotating portion 52 in the rotation axis direction corresponding to (equivalent to) the pressing load of the inner friction member 22 to the load sensor 62. In other words, an annular transmission member 66 is provided between the linear motion portion 54 and the load sensor 62 in the rotation axis direction.

[0042] (Operation of the Electric Braking Device 10)

[0043] Next, the operation of the electric brake device 10 will be described.

[0044] like Figure 1As shown, for example, when the driver depresses the brake pedal (not shown), the electric motor 32 drives the rotating portion 52 to rotate in the forward direction in a state where the rotation torque of the electric motor 32 is increased by the transmission mechanism 36. Then, the linear motion portion 54 moves toward the claw 16 side (one side in the rotation axis direction) of the caliper housing 14 by the screwing action of the external thread portion 52m and the internal thread portion 54f, and the piston 24 also moves toward the claw 16 side of the caliper housing 14 together with the linear motion portion 54. As a result, the piston 24 abuts against the inner friction member 22, and the inner friction member 22 can be pressed toward the claw 16 side of the caliper housing 14. Furthermore, when the piston 24 abuts against the inner friction member 22, the reaction force received from the rotating body 12 causes the caliper housing 14 to move through the sliding pin of the caliper housing 14 (not shown), so that the outer friction member 20 abuts against the rotating body 12. Thus, the two friction members 20 and 22 as the friction members are pressed against the rotating body 12 so as to be sandwiched therebetween, and a braking force can be generated on the wheels of the vehicle.

[0045] (Effect)

[0046] Next, the effects of the embodiment of the present invention will be described.

[0047] In the electric brake device 10, as described above, the leaf spring 56 for urging the rotating part 52 toward the transmission mechanism 36 side (the other side in the rotation axis direction) is arranged between the direct-acting part 54 and the transmission mechanism 36 in the rotation axis direction. Since both end portions 56e of the leaf spring 56, which is a second engagement portion engaged with the cylinder body 18, are arranged closer to the transmission mechanism 36 side than the peripheral edge portion of the through hole 56h of the leaf spring 56, which is a first engagement portion engaged with the rotating part 52, in the rotation axis direction, the leaf spring 56, which is a urging member, urges the rotating part 52 from the direct-acting part 54 side to the transmission mechanism 36 side. Thus, since the both end portions 56e of the leaf spring 56 and the direct-acting part 54 do not interfere with each other, the degree of freedom of arrangement of the direct-acting conversion mechanism 50 can be improved, and the axial displacement of the rotating part 52 caused by the vibration (shock) from the wheel can be suppressed, thereby achieving an improvement in the vibration resistance of the direct-acting conversion mechanism 50.

[0048] In particular, when the peripheral edge portion of the through hole 56h of the leaf spring 56 is relatively rotatably engaged with the circumferential groove 52g of the rotating portion 52 via a plurality of sliding members such as balls 58, the rotational movement of the rotating portion 52 is less likely to be hindered by the leaf spring 56. As a result, the increase in loss torque can be further suppressed, and the working efficiency of the electric brake device 10 can be improved.

[0049] In the electric brake device 10, the load sensor 62 is provided between the direct-acting portion 54 and the leaf spring 56 in the direction of the rotation axis, and the transmission member 66 is provided between the direct-acting portion 54 and the load sensor 62 in the direction of the rotation axis. The transmission member 66 transmits the force in the direction of the rotation axis corresponding to the pressing load from the rotating portion 52 to the load sensor 62, so when the leaf spring 56 applies force to the rotating portion 52 toward the transmission mechanism 36 side, the load sensor 62 is applied to the transmission mechanism 36 side via the transmission member 66. Thus, according to the embodiment of the present invention, the axial displacement of the load sensor 62 caused by the vibration of the wheel is suppressed, and the effect of suppressing the reduction of the detection accuracy of the load sensor 62 and preventing the load sensor 62 from being damaged can be obtained. In addition, by configuring the transmission member 66 separately from the rotating portion 52, there is no portion protruding from the rotating portion 52 in the radial direction of the rotating portion 53, so the rotating portion 52 can be formed by rolling, and the rotating portion 52 can be manufactured at a low cost.

[0050] In addition, in the electric brake device 10, the two end portions 56e of the leaf spring 56 as the second joint portion of the urging member are prevented from rotating relative to the cylinder body portion 18. That is, the leaf spring 56 is prevented from rotating together with the rotational movement of the rotating portion 52, thereby helping to suppress the generation of foreign matter due to sliding wear of the two end portions 56e of the leaf spring 56, and helping to improve the durability of the leaf spring 56 itself.

[0051] In addition, by engaging the two end portions 56e of the leaf spring 56 formed in a strip shape with the two recessed portions 18d of the cylinder body 18, the leaf spring 56 can be prevented from rotating with a simple structure. In addition, here, a convex portion can be provided in the cylinder body 18 instead of the recessed portion 18d, and the rotation is prevented by engaging the convex portion with the two end portions 56e of the leaf spring 56.

[0052] Furthermore, by joining the strip-shaped leaf spring 56 to the cylindrical cylinder 18, a space can be provided between the cylinder 18 and the leaf spring 56 in the radial direction of the rotating portion 52. This allows components of the electric brake device 10, such as the sensor connection portion 64, to be arranged, thus contributing to miniaturization of the electric brake device 10.

[0053] The rotating part 52 has a cylindrical rotating shaft part concentric with its axis, and a concave part (circumferential groove 52g) or a convex part (protrusion 52b) extending in the circumferential direction is formed on the outer peripheral part of the rotating shaft part of the rotating part 52, and the force applying member is constituted by a leaf spring 56 formed with a through hole 52h for inserting the rotating shaft part of the rotating part 52. By setting the peripheral edge part of the through hole 56h of the leaf spring 56 as the first engaging part, the rotating shaft part of the rotating part 52 can be urged with a uniform force, and the durability of the direct motion conversion mechanism 50 can be improved compared with the case where the rotating shaft part of the rotating part 52 is urged with a biased force. In addition, the leaf spring 56 can be engaged with the rotating part 52 only by the process of passing the rotating part 52 through the through hole 56h of the leaf spring 56, so that the assemblability of the electric brake device 10 can be improved.

[0054] 〔appendix〕

[0055] The present invention is not limited to the description of the above-mentioned embodiments, and various changes can be made within the scope indicated by the claims. The embodiments obtained by appropriately combining the technical means disclosed in the embodiments are also included in the technical scope of the present invention. For example, in this embodiment, the electric brake device 10 is described as an example of an electric disc brake, but it can also be applied to a drum brake. In addition, it can also be applied to a structure in which the direct-acting part 54 rotates and the rotating part 52 moves directly.

Claims

1. An electric brake device, which transmits the rotation of an electric motor to a direct-acting conversion mechanism through a transmission mechanism, converts the rotational motion transmitted by the transmission mechanism from the rotational motion of a rotating part to the linear motion of a direct-acting part in the direct-acting conversion mechanism, and presses a friction member linked to the linear motion of the direct-acting part against a rotating body rotating with a wheel to generate a braking force on the wheel, wherein: The electric brake device comprises: a housing for accommodating the direct-acting conversion mechanism disposed between the friction member and the transmission mechanism in the direction of the rotation axis of the rotating portion; and The force-applying component is arranged between the direct-acting portion and the transmission mechanism in the direction of the rotation axis, and has a first engaging portion engaged with the rotating portion, and a second engaging portion engaged with the housing on the transmission mechanism side closer to the first engaging portion. The force-applying component applies force to the rotating portion from the direct-acting portion side to the transmission mechanism side.

2. The electric brake device according to claim 1, wherein: have: a load sensor disposed between the linear motion portion and the force applying member in the direction of the rotation axis, and detecting a pressing load of the friction member on the rotating body; and The transmission member is provided between the linear motion portion and the load sensor in the rotation axis direction, and transmits a force corresponding to the pressing load from the rotation portion in the rotation axis direction to the load sensor.

3. The electric brake device according to claim 1, wherein: The second engagement portion is prevented from rotating relative to the housing.

4. The electric brake device according to any one of claims 1 to 3, wherein: The urging member is a belt-shaped leaf spring, and the housing joined to the leaf spring is cylindrical.

5. The electric brake device according to claim 1, wherein: The rotating part has a cylindrical rotating shaft part which is concentric with its axis. A concave portion or a convex portion extending in the circumferential direction is formed on the outer peripheral portion of the rotating shaft portion. The urging member is a leaf spring having a through hole formed therein for inserting the rotating shaft portion. The peripheral edge portion of the through hole of the leaf spring serves as the first engaging portion.

6. The electric brake device according to claim 3, wherein: The force applying member is a strip-shaped leaf spring. The housing is formed with concave or convex portions that are respectively engaged with both end portions of the leaf spring and restrict the leaf spring from rotating together with the rotating portion.

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