JP2017010286A - damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a damper having a longer service life which, while braking a moving member that reciprocates along an axial center, applies reaction force having hysteresis characteristics to the moving member.SOLUTION: A cam surface 745 slanted with respect to an axial center O is provided on an outer periphery of a push rod 7 to be braked by a damper 8. The damper 8 has: a cylindrical slider 4 having, on the inner periphery thereof, a cam surface 42 that makes surface contact with the cam surface 745 of the push rod 7; a coil spring 30 for energizing the slider 4 in a direction in which the cam surface 42 of the slider 4 is pressed against the cam surface 745 of the push rod 7; and a cylindrical case 1 for housing them. The slider 4 has a slit 45 formed extending over the whole length thereof. When the push rod 7 moves along the axial center O thereof, the slider 4 is expanded by contact between the cam surface 42 of the slider 4 and the cam surface 745 of the push rod 7, and moves together with the push rod 7 while pressing the entire area of an outer peripheral surface 41 thereof against an inner peripheral surface 12 of the case 1.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a direct acting friction mechanism having hysteresis characteristics, and more particularly to a damper suitable for braking a moving member that moves linearly, such as a push rod of a brake actuator that assists a driver to step on a pedal.

  In Patent Document 1, using a hysteresis characteristic of a damper including a pair of cams, an appropriate load is applied to the depression of the accelerator pedal, and the driver's foot when the accelerator pedal is held at a substantially constant position. An accelerator pedal unit that reduces this burden is described.

  In this accelerator pedal unit, the rotation of the accelerator pedal arm is transmitted to the rotation shaft of the damper via a transmission mechanism composed of a link member or the like, whereby the bidirectional rotation of the accelerator pedal arm is braked. Specifically, one end of the link member is fixed to the rotation shaft of the damper so that the rotation shaft of the damper is rotated by the rotation of the link member. On the other hand, an engaging member is fixed to the accelerator pedal arm at the opposite end of the accelerator pedal across the rotation axis of the accelerator pedal arm, and the engaging member is slidably held by the link member. As a result, when the accelerator pedal arm rotates, the rotation shaft of the damper rotates in the direction corresponding to the rotation direction of the accelerator pedal arm via the link member, and due to the hysteresis characteristic of the damper, an appropriate load is applied when the accelerator pedal is depressed. The load is reduced when the accelerator pedal is returned (paragraphs 0071 to 0084, FIGS. 13 to 19 and the like).

  Patent Document 2 describes a damping mechanism incorporated in a linear tensioner that applies an appropriate tension to a belt with a spring. In this damping mechanism, the cone-shaped piston is pushed into the tapered hole of the cam body urged toward the piston by the spring in accordance with the load from the belt. The cam body is formed with a slot that does not reach the other end face in the axial direction from one end face so that the diameter of the tapered hole of the cam body is increased by pushing the cone-shaped piston (FIG. 9). ) When the cone-shaped piston is pushed into the tapered hole of the cam body, the cam body moves in the direction of compressing the spring while sliding the outer peripheral surface against the inner wall of the housing due to the increase in the diameter of the tapered hole. At this time, a damping force having a hysteresis characteristic is obtained by friction generated between the outer peripheral surface of the cam body and the inner wall of the housing.

JP 2002-12052 A Japanese Patent No. 3792160

  By the way, when a pedal is depressed in an automobile brake or the like, an appropriate load corresponding to the amount of pedal depression is given to the driver's foot, while the pedal operation that the load on the driver's foot is reduced while holding the pedal. In order to realize the feeling, it is necessary to mount a special brake pedal unit incorporating a damper similar to the damper of the conventional accelerator pedal unit on the automobile. For example, any general-purpose brake pedal arm can be selected as long as it can provide the brake pedal arm with a load having hysteresis characteristics according to the required pedal operation feeling from the push rod side of the brake actuator that assists the driver's pedal depression. By simply connecting to the push rod, the required pedal operation feeling can be stably realized.

  However, since the damper incorporated in the accelerator pedal unit described in Patent Document 1 brakes the bi-directional rotation of the accelerator pedal arm, for example, a linearly moving moving member such as a push rod of a brake actuator is used. It is difficult to apply to braking as it is. On the other hand, in the damping mechanism described in Patent Document 2, there is a possibility that the outer peripheral surface of the cam main body does not uniformly contact the inner wall of the housing, and the outer peripheral surface of the cam main body wears unevenly. Thereby, the lifetime of a cam main body may fall.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a longer-life damper that applies a reaction force having hysteresis characteristics to a moving member while braking the moving member that reciprocates along an axis. Is to provide.

  In order to solve the above-mentioned problem, in the present invention, the cam surface on the inner peripheral surface of the cylindrical slider in which the slit extending over the entire length is moved by the elastic force of the elastic body with respect to the cam surface in the outer peripheral surface of the moving member. Since the member is pressed in the axial direction of the member, when the moving member moves along the axial center, the slit is caused to contact the entire inner peripheral surface of the case by the contact between the cam surface of the slider and the cam surface of the moving member. It moves with the moving member while pressing against the surface.

For example, the damper according to the present invention is
A housing in which a moving member having a first cam surface inclined with respect to the axis around the axis is inserted so as to reciprocate along the axis;
The housing is disposed in the housing so as to be movable along the axis of the moving member, and surrounds the outer peripheral surface facing the inner peripheral surface of the housing, the moving member around the axis of the moving member, and the first A cylindrical slider having an inner peripheral surface including a second cam surface facing the one cam surface;
A first elastic body that biases the slider in the axial direction of the shaft such that the second cam surface is pressed against the first cam surface in the axial direction of the shaft. ,
The slider is formed with slits that pass through both ends of the slider,
When the moving member reciprocates along the axis of the moving member, the slider elastically expands the slit by contact with the first cam surface and the second cam surface. It is deformed and reciprocates along the axis of the moving member together with the moving member while pressing the outer peripheral surface of the slider against the inner peripheral surface of the housing.

In this damper,
The inner peripheral surface of the housing includes first and second regions that are arranged in the moving direction of the moving member and have different friction coefficients with the outer peripheral surface of the slider.
The slider may move along the axis of the moving member while sequentially sliding the outer peripheral surface with the first and second regions.

  According to the present invention, the cylindrical slider having a slit formed over its entire length is slightly expanded by the contact between the cam surface on the inner periphery and the cam surface on the outer periphery of the moving member that moves along the axis. A long-life damper that applies a reaction force having hysteresis characteristics to the moving member while braking the moving member that reciprocates along the shaft center because the entire outer peripheral surface is pressed against the case and moves together with the moving member. Can be realized.

FIG. 1 is a view for explaining a state in which a brake pedal arm 81 is attached to a push rod 7 of an electric brake actuator incorporating a damper 8 according to an embodiment of the present invention. FIG. 2 is a component development view of the damper 8 including the push rod 7. 3 (A) is a front view of the push rod 7, and FIGS. 3 (B) and 3 (C) are AA and BB sectional views of FIG. 3 (A). 3 (D) is a right side view of the push rod 7. 4A is a front view of the case 1, FIG. 4B is a right side view of the case 1, and FIG. 4C is a cross-sectional view taken along the line CC in FIG. 4B. is there. 5A, FIG. 5B, and FIG. 5C are a front view, a left side view, and a right side view of the slider 4, and FIG. 5D is a cross-sectional view of FIG. It is D sectional drawing, and FIG.5 (E) is EE sectional drawing of FIG.5 (C). 6A is a diagram for explaining the state of the slider 4 in a state where the brake pedal is not depressed (initial state), and FIGS. 6B and 6C are diagrams when the brake pedal is depressed. It is a figure for demonstrating the state of the slider 4 in.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the present embodiment, as an example of a damper whose braking target is a moving member that reciprocates along the axial direction, a damper 8 incorporated in an electric brake actuator that assists the depression of a brake pedal is given.

  FIG. 1 is a schematic view showing a state in which a brake pedal arm 81 is attached to a push rod 7 of an electric brake actuator in which a damper 8 according to the present embodiment is incorporated, and FIG. 2 shows a push rod 7 to be braked. FIG.

  As shown in the figure, the damper 8 according to the present embodiment has a push rod 7 that is a moving member that transmits a pedaling force received by the brake pedal to a piston in the brake cylinder along the axis O direction of the push rod 7. A linear motion type damper that is supported so as to be reciprocally movable. For example, a housing (an assembly of the case 1 and the cover 2) having two rod insertion ports 50 and 51 into which the push rod 7 is inserted in the direction of the axis O. 5 and a braking portion 6 that is housed inside the housing 5 (braking portion housing chamber 15 described later: see FIG. 6) and applies a load having a hysteresis characteristic to the push rod 7.

  Here, the housing 5 includes a hollow cylindrical bottomed case 1 surrounding the push rod 7 around the axis O, and a cover 2 that closes the opening 10 of the case 1. As a storage space for the brake unit 6, a cylindrical brake unit storage chamber surrounded by an inner wall surface (inner peripheral surface 12, bottom surface 14) of the case 1 and a back surface (surface directed toward the case 1) 21 of the cover 2. 15 is formed (see FIG. 6).

  On the other hand, the braking unit 6 is moved to the shaft center of the housing 5 (axis O of the push rod 7) together with the push rod 7 while sliding the outer peripheral surface 41 on the inner peripheral surface of the housing 5 (inner peripheral surface 12 of the case 1). A so-called radial section C-shaped slider 4 reciprocating along the bottom surface of the housing 5 (the bottom surface 14 of the case 1) and one end surface of the slider 4 (a surface facing the bottom surface 14 side of the case 1; hereinafter, front end surface) ) 44 and the elastic body 3 that urges the slider 4 toward the back surface 21 of the cover 2 in the direction of the axis of the housing 5 (the axis O of the push rod 7). The push rod 7 is braked with a braking force generated by the frictional resistance between the outer peripheral surface 41 of the slider 4 and the inner peripheral surface 12 of the case 1 that is displaced while compressing the. The elastic body 3 may be anything that urges the slider 4 toward the back surface 21 of the cover 2 with an elastic force corresponding to the displacement of the slider 4 in the axis O direction. The case where the coil spring 30 is provided as such an elastic body 3 is illustrated.

  By incorporating the damper 8 having such a configuration in the electric brake actuator, the push rod 7 that reciprocates along the axis O in response to the depression of the brake pedal is required to operate the pedal over the entire stroke. It is possible to brake with a load having a hysteresis characteristic according to the feeling. Hereinafter, the push rod 7 to be braked by the damper 8 and the configuration of the damper 8 (housing 5 and braking portion 6) will be described in detail.

  First, the push rod 7 to be braked will be described.

  3A is a front view of the push rod 7, FIGS. 3B and 3C are AA and BB sectional views of FIG. 3A, and FIG. 3D. FIG. 3E is a right side view of the push rod 7, and FIG. 3E is an enlarged view of the rectilinear cam portion 742 of the push rod 7.

  As shown in the figure, the push rod 7 is included in the piston driver 73 that drives the piston in the brake cylinder of the electric brake actuator and the inner peripheral surface 46 of the slider 4 in this order from the one end surface 71 side along the axis O. A stepped shaft portion 74 having a cam surface 745 that is slidably supported by a cam surface 42 described later, and a pedal arm connecting portion 75 to which a brake pedal arm 81 is connected. This push rod 7 is disposed inside the housing 5 (accommodating the braking portion) until the piston drive portion 73 inserted from one rod insertion port 50 of the housing 5 protrudes from the other rod insertion port 51 of the housing 5 (see FIG. 1). Inserted into the chamber 15).

  The piston drive part 73 protrudes from the other rod insertion port 51 of the housing 5 toward the rear end surface of the piston in the brake cylinder to the outside of the housing 5 (outside of the braking part accommodating chamber 15). When the push rod 7 moves (advances) toward the brake cylinder by depressing the brake pedal, the front end surface (one end surface of the push rod 7) 71 of the piston driving unit 73 is abutted against the rear end surface of the piston, and the brake cylinder. The piston moves forward. In addition, this piston drive part 73 should just have arbitrary shapes (for example, cylindrical shape) suitable for butting to the piston rear-end surface in a brake cylinder.

  The stepped shaft portion 74 has a stepped shape in which two cylindrical portions 741 and 743 having different diameters and longer than the maximum stroke of the push rod 7 are formed coaxially. A piston driving unit 73 is connected to one cylindrical part (hereinafter referred to as a small diameter part) 741, and a pedal arm connecting part is connected to the other cylindrical part (hereinafter referred to as a large diameter part) 743 having a diameter larger than that of the small diameter part 742. 75 is connected. Further, between the small diameter portion 741 and the large diameter portion 743, there is formed a frustum-like straight advance cam portion 742 that is tapered so as to connect the outer circumferences of the cylindrical portions 741 and 743. Such a frustum-shaped rectilinear cam portion 742 has an outer diameter that increases as it approaches from the small diameter portion 741 to the large diameter portion 743, and an outer peripheral surface 746 of the frustum-like linearly moving cam portion 742 approaches the large diameter portion 743. A conical surface-shaped curved region 745 inclined with respect to the axis O is included so that the distance from the axis O becomes narrow. The curved surface region 745 functions as the cam surface 745 of the rectilinear cam portion 742 supported by a cam surface 42 described later included in the inner peripheral surface 46 of the slider 4.

  The stepped shaft portion 74 is inserted into the inside of the housing 5 (the braking portion accommodating chamber 15) through one rod insertion port 50 of the housing 5. As will be described later, in the braking portion accommodating chamber 15 of the housing 5, the cam surface 42 of the slider 4 goes straight by the restoring force of the coil spring 30 compressed between the front end surface 44 of the slider 4 and the bottom surface 14 of the case 1. Since it is pressed against the cam surface 745 of the cam portion 742, when the push rod 7 moves forward (moves in the direction α in FIG. 1) by stepping on the brake pedal, the slider 4 moves to the cam surface of the straight cam portion 742. The cam surface 42 is slid by 745 and slightly elastically deformed, and moves forward together with the push rod 7 while pressing the outer peripheral surface 41 against the inner wall surface of the housing 5 (the inner peripheral surface 12 of the case 1).

  The pedal arm connecting portion 75 protrudes from the one rod insertion port 50 of the housing 5 to the outside of the housing 5 (outside of the braking portion accommodating chamber 15) toward the side opposite to the piston driving portion 73. The pedal arm connecting portion 75 has, for example, a cylindrical shape, and a clevis joint 80 for rotatably holding the brake pedal arm 81 is fixed to an end surface (the other end surface of the push rod 7) 72. A screw hole 751 is formed. For example, the brake pedal arm 81 is rotatably connected to the push rod 7 by screwing a bolt 83 fixed to the clevis joint 80 with a nut 84 into the screw hole 751 and fastening the bolt 83 and the nut 85. (See FIG. 1). Accordingly, when the brake pedal arm 81 rotates in both directions around the rotation shaft 82, the push rod 7 reciprocates along the axis O in conjunction with the brake pedal arm 81.

  Such a push rod 7 may be integrally formed as a whole, or individual parts (for example, a part including a piston drive unit 73, a part including a rectilinear cam part 742, a pedal arm connecting part) 75 parts) may be connected.

  Next, the configuration of the damper 8 (housing 5 and braking portion 6) will be described.

  As described above, the housing 5 includes the hollow cylindrical bottomed case 1 and the cover 2 that closes the opening 10 of the case 1, and the braking portion 6 is accommodated therein. A braking portion accommodating chamber 15 is formed (see FIG. 2).

  4A is a front view of the case 1, FIG. 4B is a right side view of the case 1, and FIG. 4C is a cross-sectional view taken along the line CC in FIG. 4B. is there.

  As illustrated, the case 1 has a bottomed cylindrical shape shorter than the push rod 7, and a screw portion 11 is formed on the inner periphery of the opening 10. On the other hand, the cover 2 has a disk shape, and a screw portion 23 fastened to the screw portion 11 formed on the inner periphery of the opening 10 of the case 1 is formed on the outer peripheral surface 22 thereof. By attaching the cover 2 to the opening 10 of the case 1 and fastening the screw portion 23 of the outer peripheral surface 22 of the cover 2 and the screw portion 11 of the opening 10 of the case 1, the back surface 21 of the cover 2 and the case 1 A columnar brake portion accommodating chamber 15 surrounded by the inner wall surface (the bottom surface 14 and the inner peripheral surface 12) is formed.

  Further, in the central region of the bottom surface 14 of the case 1, the outer diameter R1 of the piston drive part 73 of the push rod 7 and the stepped shaft part 74 are located at a position where the axis O of the braking part accommodating chamber 15 of the housing 5 passes. A through hole 13 having an inner diameter r1 larger than the outer diameter R2 of the small diameter portion 741 is formed. Similarly, the outer diameter R4 of the pedal arm connecting portion 75 of the push rod 7 and the large diameter of the stepped shaft portion 74 are also located in the central region of the cover 2 at a position where the axis O of the braking portion accommodating chamber 15 of the housing 5 passes. A through hole 24 having an inner diameter larger than the outer diameter R3 of the diameter portion 743 is formed. By attaching the cover 2 to the opening 10 of the case 1, the through hole 24 of the cover 2 becomes one rod insertion port 50 of the housing 5, and the through hole 13 of the bottom surface 14 of the case 1 is the other hole of the housing 5. It becomes the rod insertion port 51.

  Further, an annular spring guide groove 16 surrounding the through hole 13 is formed on the bottom surface 14 of the case 1. When the coil spring 30 is inserted into the case 1, one end 31 of the coil spring 30 is fitted into the spring guide groove 16 and fixed.

  For example, a flange 17 for fixing the damper 8 to a housing of an electric brake actuator or the like is formed on the outer periphery of the case 1 as necessary.

  On the other hand, as described above, the braking unit 6 includes the slider 4 and the coil spring 30 that biases the slider 4 toward the back surface 21 of the cover 2. The push rod 7 is braked by the braking force generated by the frictional resistance between the outer peripheral surface 41 and the inner peripheral surface 12 of the case 1.

  5A, FIG. 5B, and FIG. 5C are a front view, a left side view, and a right side view of the slider 4, and FIG. 5D is a cross-sectional view of FIG. It is D sectional drawing, and FIG.5 (E) is EE sectional drawing of FIG.5 (C).

  As illustrated, the slider 4 is an elastically deformable cylindrical member having a C-shaped radial cross section. Specifically, the slider 4 is formed with a slit 45 in the direction of the axis O extending from one end face (hereinafter referred to as a rear end face) 43 to the front end face 44 so that the width t of the slit 45 extends over the entire length of the slider 4 ( That is, it is a cylindrical integrally molded product made of, for example, resin that can be elastically deformed (so that the outer diameter R5 increases over the entire length of the slider 4). In addition, a groove 47 is formed on the inner peripheral surface 46 of the slider 4 from the rear end surface 43 to the front end surface 44 in the direction of the axis O so that the slider 4 is easily elastically deformed. Also good.

  The slider 4 is disposed in the braking portion accommodating chamber 15 in a state where the rear end surface 43 is brought into contact with the back surface 21 of the cover 2 by being urged by the coil spring 30, and the inner peripheral surface 46 of the slider 4 is one side of the housing 5. The rod insertion hole 40 into which the stepped shaft portion 74 of the push rod 7 inserted from the rod insertion port 50 is inserted is formed. On the inner circumferential surface 46 of the slider 4 surrounding the stepped shaft portion 74 of the push rod 7, the axial center O of the push rod 7 is reduced so that the inner diameter of the rod insertion hole 40 decreases as the distance from the rear end surface 43 of the slider 4 increases. On the other hand, a conical surface-shaped curved region (cam surface 42) inclined substantially at the same angle as the cam surface 745 of the rectilinear cam portion 742 is formed. Such a cam surface 42 has a substantially inverted shape of the outer peripheral surface 746 of the rectilinear cam portion 742 of the push rod 7, and the rectilinear cam portion of the push rod 7 inserted from one rod insertion port 50 of the housing 5. It faces the cam surface 745 of 742 and comes into surface contact with this cam surface 745. Thus, the slider 4 supports the cam surface 745 of the rectilinear cam portion 742 of the push rod 7 with the cam surface 42 of the inner peripheral surface 46, and the outer peripheral surface on the inner peripheral surface of the housing 5 (inner peripheral surface 12 of the case 1). 41 is slid along with the push rod 7 along the axis of the housing 5 (the axis O of the push rod 7).

  When the push rod 7 is moved forward by the depression of the brake pedal and the straight cam portion 742 is pushed into the rod insertion hole 40 of the slider 4 urged toward the back surface 21 of the cover 2 by the coil spring 30, the slider 4 Due to the force received from the cam surface 745 of the rectilinear cam portion 742, the cam surface 42 is slid on the cam surface 745 of the rectilinear cam portion 742, and the slider 4 is slightly elastically deformed so that the width t of the slit 45 is widened. Thus, the slider 4 pushes the push rod 7 while pressing the entire outer peripheral surface 41 against the inner wall surface of the housing 5 (the inner peripheral surface 12 of the case 1) by a radial component force of the drag from the cam surface 745 of the rectilinear cam portion 742. Along with this, the coil spring 30 is further compressed. At this time, the friction between the outer peripheral surface 41 of the slider 4 and the inner peripheral surface 12 of the case 1 acts on the slider 4 to prevent the slider 4 from moving forward. The slider 4 pushed by the push rod 7 moves forward while receiving the restoring force of the coil spring 30 and the braking force generated by the frictional resistance between the outer peripheral surface 41 of the slider 4 and the inner peripheral surface 12 of the case 1. The driver's foot (drive source) that depresses the brake pedal is given an appropriate load according to the amount of depression of the brake pedal.

  In the present embodiment, the slider 4 is formed with the slit 45 in the axial center O direction over the entire length thereof, but the slit of the slider 4 is formed so as to come out to both end faces 43 and 44 of the slider 4. What is necessary is not to be parallel to the axis O of the push rod 7. For example, the slider 4 may be formed with slits that pass through both end faces 43 and 44 in an inclined direction with respect to the axis O of the push rod 7. Thereby, the outer peripheral surface 41 of the slider 4 can be slid with the whole area of the inner peripheral surface 12 of the case 1 by the reciprocating movement of the slider 4.

  The coil spring 30 is disposed between the bottom surface 14 of the case 1 and the front end surface 44 of the slider 4 with one end 31 fitted in the spring guide groove 16. The coil spring 30 has an axial center O of the slider 4 from the total length in the direction of the axis O of the brake chamber 15 (distance L2 between the back surface 21 of the cover 2 and the bottom surface 14 of the case 1; see FIG. 6A). It has a free length longer than the length obtained by subtracting the direction length L1 (see FIG. 5A). Therefore, the coil spring 30 is compressed (preloaded) between the front end surface 44 of the slider 4 and the bottom surface 14 of the case 1 in the initial state of the damper 8 (the state of FIG. 6A in which the brake pedal is not depressed). When the slider 4 is driven toward the bottom surface 14 of the case 1 by depressing the brake pedal, the compression is further performed between the front end surface 44 of the slider 4 and the bottom surface 14 of the case 1. As a result, the slider 4 is urged in the direction of the axis of the housing 5 (the axis O of the push rod 7) toward the back surface 21 of the cover 2 by an elastic force corresponding to the amount of displacement toward the brake cylinder. The cam surface 42 is pressed against the cam surface 745 of the rectilinear cam portion 742. At this time, on the cam surface 42 of the slider 4, the elastic force of the coil spring 30 and the friction between the outer peripheral surface 41 of the slider 4 and the inner peripheral surface 12 of the case 1 from the cam surface 745 of the rectilinear cam portion 742. A load according to resistance or the like is applied.

  Such a damper 8 is assembled to the push rod 7 by the following procedure, for example, and is assembled to the electric brake actuator.

  First, the coil spring 30 is inserted into the opening 10 of the case 1 from the one end 31 so that the one end 31 of the coil spring 30 is fitted into the spring guide groove 16 of the bottom surface 14 of the case 1. 1 is disposed inside. Next, the slider 4 is inserted from the opening 10 of the case 1 with the front end surface 44 of the slider 4 facing the bottom surface 14 side of the case 1. Thus, the slider 4 is disposed inside the case 1 with the front end face 44 being in contact with the other end 32 of the coil spring 30.

  Then, the cover 2 is attached to the opening 10 of the case 1, and the screw portion 23 of the outer peripheral surface 22 of the cover 2 is fastened to the screw portion 11 of the opening 10 of the case 1. As a result, a braking portion accommodating chamber 15 in which the braking portion 6 is accommodated is formed in the housing 5. As described above, the free length of the coil spring 30 is larger than the distance obtained by subtracting the length L2 of the slider 4 in the axial center O direction from the total length L1 in the axial center O direction of the braking portion accommodating chamber 15. The coil spring 30 accommodated in the accommodation chamber 15 is slightly compressed (preloaded) between the front end surface 44 of the slider 4 having the rear end surface 43 in contact with the back surface 21 of the cover 2 and the bottom surface 14 of the case 1. .

  Thereafter, the push rod 7 is inserted into one rod insertion port 50 of the housing 5 from the piston driving unit 73 side while aligning the axial center O of the push rod 7 with the axial center O of the braking portion accommodating chamber 15. The piston drive part 73 is inserted into the brake part accommodating chamber 15 of the housing 5 from the other rod insertion port 51 of the housing 5 to a position where the piston drive part 73 protrudes by a predetermined length. At this time, in the brake portion accommodating chamber 15 of the housing 5, the piston drive portion 73 of the push rod 7 passes through the rod insertion port 40 of the slider 4 and the inside of the coil spring 30 in this order. For this reason, in the braking part accommodation chamber 15 of the housing 5, the slider 4 and the coil spring 30 are mounted on the outer periphery of the small diameter part 741 of the stepped shaft part 74 of the push rod 7.

  After the damper 8 is assembled to the push rod 7 in this way, the damper 8 is attached to the electric brake actuator so that the front end surface 71 of the piston drive portion 73 of the push rod 7 abuts the rear end surface of the piston in the brake cylinder. Secure to the housing. Thereby, the damper 8 which supported the push rod 7 so that the reciprocation along the axial center O was supported is integrated in an electric brake actuator. Next, the operation of the damper 8 incorporated in the electric brake actuator will be described.

  FIG. 6 is a schematic diagram for explaining a change in the state of the brake unit accommodation chamber 15 before and after the brake pedal is depressed. FIG. 6A shows the slider 4 in a state where the brake pedal is not depressed (initial state). 6 (B) and 6 (C) show the state of the slider 4 when the brake pedal is depressed. However, in FIGS. 6A to 6C, the outline of the coil spring 30 is indicated by a chain line, so that the internal layout of the braking portion accommodating chamber 15 of the housing 5 is simply displayed.

  As shown in FIG. 6A, in the initial state of the damper 8, the slider 4 in the braking portion accommodation chamber 15 of the housing 5 is directed toward the cover 2 in the direction of the axis O of the push rod 7 by the preloaded coil spring 30. And is positioned at an initial position (for example, a position where the rear end surface 43 of the slider 4 and the back surface 21 of the cover 2 are in contact).

  Here, when the driver depresses the brake pedal and the brake pedal arm 81 rotates around the rotation shaft 82 in a predetermined direction A (see FIG. 1), the push rod 7 is interlocked with the brake pedal arm 81 and It moves in the direction α toward the figure. In the following, movement in the direction α toward the brake cylinder is called forward, and movement in the direction away from the brake cylinder (opposite to the direction α) β is called backward.

  As shown in FIG. 6B, when the push rod 7 moves forward and the cam surface 745 of the rectilinear cam portion 742 of the push rod 7 comes into contact with the cam surface 42 of the inner peripheral surface 46 of the slider 4, then the push rod 7 advances while pushing the slider 4 biased toward the back surface 21 of the cover 2 by the coil spring 30 in the direction of the axis O with a force corresponding to the pedaling force received by the brake pedal.

  Here, the slider 4 is slightly elastically deformed so that the width of the slit 45 is widened over the entire length of the slider 4 (t1 <t2), and a radial component force F1 of a drag exerted from the rectilinear cam portion 742 of the push rod 7 is obtained. Thus, the entire outer peripheral surface 41 is pressed against the inner peripheral surface 12 of the case 1 to advance together with the push rod 7. For this reason, during the forward movement of the push rod 7, a frictional resistance that prevents the forward movement of the slider 4 acts on the outer peripheral surface 41 of the slider 4 by sliding with the inner peripheral surface 12 of the case 1.

  Also, as shown in FIG. 6C, the distance between the front end surface 44 of the slider 4 and the bottom surface 14 of the case 1 is gradually narrowed by the advance of the slider 4, and the coil spring 30 is further compressed. As the slider 4 moves forward, the slider 4 is urged toward the cam surface 745 of the rectilinear cam portion 742 of the push rod 7 with a larger elastic force. Therefore, during the forward movement of the push rod 7, the drag force exerted on the cam surface 42 of the inner peripheral surface 46 of the slider 4 from the straight cam portion 742 of the push rod 7 gradually increases, and the radial force component F2 of the drag force causes the case 1 The vertical load that the slider 4 pressed against the inner peripheral surface 12 receives from the inner peripheral surface 12 of the case 1 also gradually increases. For this reason, the frictional resistance between the outer peripheral surface 41 of the slider 4 and the inner peripheral surface 12 of the case 1 gradually increases as the slider 4 advances as the push rod 7 advances. Thus, the forward movement of the slider 4 is hindered by the braking force generated from the frictional resistance that gradually increases with the forward movement of the slider 4.

  As described above, during the forward movement of the push rod 7, the slider 4 pushed by the push rod 7 advances while compressing the coil spring 30 and receives a braking force generated from a frictional resistance that increases as the slider 4 advances. Therefore, an appropriate load corresponding to the amount of depression of the brake pedal is given to the foot (drive source) of the driver who depresses the brake pedal.

  Here, when the driver temporarily stops the depression of the brake pedal and the forward movement of the push rod 7 stops, the outer peripheral surface 41 of the slider 4 is now in a direction that prevents the coil spring 30 from restoring (a direction that prevents the slider 4 from moving backward). ) Is received from the inner peripheral surface 12 of the case 1. For this reason, the load applied to the foot of the driver holding the brake pedal at a fixed position is rapidly reduced.

  When the driver weakens the pedaling force, the slider 4 receives the restoring force of the coil spring 30 compressed by the front end surface 44 and the bottom surface 14 of the case 1, and the cam surface 42 in contact with the cam surface 745 of the linear cam portion 742. Then, push back the push rod 7 and start moving backward. At this time, the slider 4 is slightly elastically deformed so that the width of the slit 45 becomes narrow over the entire length of the slider 4, and moves backward while pressing the entire outer peripheral surface 41 against the inner peripheral surface 12 of the case 1. For this reason, during the backward movement of the push rod 7, a frictional resistance that prevents the backward movement of the slider 4 acts on the outer peripheral surface 41 of the slider 4 by sliding with the inner peripheral surface 12 of the case 1.

  As shown in FIG. 6B, the distance between the front end surface 44 of the slider 4 and the bottom surface 14 of the case 1 gradually increases due to the retraction of the slider 4, and the coil spring 30 is in the preload state in the initial state of the damper 8. Since the state is gradually restored to the state shown in FIG. 6A, the force that presses the slider 4 against the cam surface 745 of the rectilinear cam portion 742 of the push rod 7 gradually decreases. Therefore, during the backward movement of the push rod 7, the drag force exerted on the cam surface 42 of the inner peripheral surface 46 of the slider 4 from the rectilinear cam portion 742 of the push rod 7 gradually decreases, and the internal force of the case 1 is reduced in the radial direction F1 of the drag force. The vertical load that the slider 4 pressed against the peripheral surface 12 receives from the inner peripheral surface 12 of the case 1 also gradually decreases. For this reason, as the slider 4 moves backward, the frictional resistance between the outer peripheral surface 41 of the slider 4 and the inner peripheral surface 12 of the case 1 gradually decreases. Thus, the backward movement of the slider 4 is prevented by the braking force generated from the frictional resistance that gradually decreases in accordance with the backward movement of the slider 4.

  As described above, since the slider 4 is retracted while pushing back the push rod 7 by the restoring force of the coil spring 30, the slider 4 receives the braking force generated from the frictional resistance that gradually decreases as the slider 4 moves backward. Is gradually retracted so that the brake pedal arm 81 rotates in the reverse direction B (see FIG. 1), and the brake pedal smoothly returns to the initial position in accordance with the movement of the driver's foot.

  As described above, according to the damper 8 according to the present embodiment, the cam surface (with respect to the axial center O of the push rod 7) in the inner peripheral surface 46 of the slider 4 having the radial cross section C shape by the restoring force of the coil spring 30. (Conical inclined surface) 42 is pushed in the direction of the axis O of the push rod 7 against the cam surface 745 of the straight cam portion 742 of the push rod 7 (conical inclined surface with respect to the axis O of the push rod 7) 745. Therefore, when the push rod 7 moves along the axis O, the slider 4 is slightly expanded by the cam surface 745 of the push rod 7 and pushes the outer peripheral surface 41 against the inner peripheral surface 12 of the case 1. It moves with the push rod 7 while applying. As a result, a frictional resistance corresponding to the displacement of the slider 4 acts on the outer peripheral surface 41 of the slider 4, and the slider 4 is braked by the braking force generated by this frictional resistance, so that the push rod 7 is moved along its axis O. A reaction force (a load having hysteresis characteristics) having different magnitudes can be applied to the drive path (driver's foot) that applies a force in a predetermined direction to the push rod 7 in a forward stroke and a return stroke of one stroke. .

  Here, the slider 4 having a C-shaped radial cross section has a slit 45 extending from the rear end face 43 to the front end face 44 and can be elastically deformed so that the width t of the slit 45 extends over the entire length thereof. During the movement of the rod 7, the entire outer peripheral surface 41 of the slider 4 can be uniformly brought into contact with the inner peripheral surface 12 of the case 1. Thereby, since the partial wear of the outer peripheral surface 41 of the slider 4 is prevented, the lifetime reduction of the damper 8 can be prevented.

  In addition, this invention is not limited to said embodiment, Many deformation | transformation are possible within the range of the summary.

  For example, in the above embodiment, the damper 8 incorporated in the electric brake actuator of the automobile is taken as an example. However, the damper according to the present invention has a hysteresis characteristic in the moving member that reciprocates along the axis. Applicable to applications where it is useful to apply a load. For example, the present invention is not limited to an electric brake actuator of an automobile, and can be incorporated into various devices having a linear motion member connected to an operation unit that receives a user operation, such as a musical instrument, a game machine, and various devices.

  In the above-described embodiment, one coil spring 30 is used as the elastic body 3 interposed between the front end surface 44 of the slider 4 and the bottom surface 14 of the case 1. There is no. For example, an elastic body other than the coil spring 30 such as rubber and a plurality of stacked disc springs may be used as the elastic body 3. In addition, depending on the device to which the damper 8 is to be incorporated, an elastic body having a nonlinear characteristic in which an elastic coefficient changes according to displacement is used as the elastic body 3, for example, a timing at which an operation unit such as a brake pedal is operated to a predetermined position. Thus, the load on the user's limb may be changed abruptly. As such an elastic body, for example, a coil spring in which compression by the front end surface 44 of the slider 4 and the bottom surface 14 of the case 1 is started at a timing when the slider 4 moves forward by a predetermined distance from the initial position, and the above-described coil spring 30. Are combined springs, unequal pitch coil springs, and the like. According to such a configuration, the timing at which the operation unit is operated to a predetermined position (push rod 7 is displaced by a predetermined amount in the direction of its axis O while giving an appropriate load to a user's limb or the like that operates the operation unit. Since the load on the user's limbs and the like can be rapidly increased at the timing), a tactile signal for notifying that the operation unit has been operated to a predetermined position can be given to the user.

  Further, the friction coefficient of the inner peripheral surface 12 of the case 1 on which the outer peripheral surface 41 of the slider 4 slides does not need to be uniform, and a plurality of cylindrical members formed of materials having different friction coefficients are arranged in the direction of the axis O. The case 1 is created by connecting to the inner surface of the case 1, or surface treatment, surface processing, or the like is performed on the inner surface 12 of the case 1, for example, as shown in FIG. 12, two or more annular regions 121 and 122 having different friction coefficients may be arranged in the direction of the axis O. Thereby, during the movement of the slider 4, the outer peripheral surface 41 of the slider 4 sequentially slides with these annular regions 121 and 122. Even with such a configuration, the load on the user's limb or the like increases suddenly or more slowly at the timing when the operation unit is operated to a predetermined position while applying an appropriate load to the user's limb or the like that operates the operation unit. Can be made. Further, since the frictional resistance between the outer peripheral surface 41 of the slider 4 and the inner peripheral surface 12 of the case 1 can be switched for each section included in one stroke of the slider, for example, a load applied to the user's limbs or the like Can be changed more finely according to the tendency or the like appearing in the operation of the operation unit by the user.

  Further, in the above-described embodiment, the frustum-like rectilinear cam portion 742 is formed on the push rod 7 that is a member to be braked, and the cam surface 745 of the rectilinear cam portion 742 is formed by the cam surface 42 on the inner periphery of the slider 4. In the case where such a cam surface 745 cannot be provided on the member to be braked although it is directly supported, for example, a conical outer peripheral surface corresponding to the inverted shape of the cam surface 745 of the rectilinear cam portion 742 is provided. A cylindrical collar member may be prepared, and a push rod may be inserted and held in the collar member.

DESCRIPTION OF SYMBOLS 1: Case, 2: Cover, 3: Elastic body, 4: Slider, 5: Housing, 6: Braking part, 7: Push rod, 8: Damper, 10: Opening part of case, 11: Screw part of case, 12 : Inner peripheral surface of the case, 13: Through hole, 14: Bottom surface of the case, 15: Braking section accommodating chamber, 16: Spring guide groove, 17: Flange, 21: Back surface of the cover, 22: Outer peripheral surface of the cover, 23: Screw part of cover, 24: through hole, 30: coil spring, 41: outer peripheral surface of slider, 42: cam surface of slider inner periphery, 43, 44: end surface of slider, 45: slit, 46: inner peripheral surface of slider 47: Groove on the inner peripheral surface of the slider 50, 51: Rod insertion port 73: Piston drive part 74: Stepped shaft part 75: Pedal arm connecting part 81: Rake pedal arm, 80: clevis joint, 82: rotating shaft of brake pedal arm, 83: bolt, 84, 85: nut, 741: small diameter portion of stepped shaft portion, 743: large diameter portion of stepped shaft portion, 742 : Straight cam portion of stepped shaft portion, 745: Cam surface of straight cam portion

Claims (4)

A housing in which a moving member having a first cam surface inclined with respect to the axis around the axis is inserted so as to reciprocate along the axis;
The housing is disposed in the housing so as to be movable along the axis of the moving member, and surrounds the outer peripheral surface facing the inner peripheral surface of the housing, the moving member around the axis of the moving member, and the first A cylindrical slider having an inner peripheral surface including a second cam surface facing the one cam surface;
A first elastic body that biases the slider in the axial direction of the shaft such that the second cam surface is pressed against the first cam surface in the axial direction of the shaft. ,
The slider is formed with slits that pass through both end faces of the slider,
When the moving member reciprocates along the axis of the moving member, the slider elastically expands the slit by contact with the first cam surface and the second cam surface. A damper that is deformed and reciprocates along the axis of the moving member together with the moving member while pressing the outer peripheral surface of the slider against the inner peripheral surface of the housing. The damper according to claim 1, wherein
The inner peripheral surface of the housing includes first and second regions that are arranged in the moving direction of the moving member and have different friction coefficients with the outer peripheral surface of the slider.
The slider moves along the axial center of the moving member while sequentially sliding the outer peripheral surface with the first and second regions. The damper according to claim 1, wherein
The slider is accommodated in the housing so that the second cam surface is pressed against the first cam surface when the slider is displaced by a predetermined distance or more in a direction in which the first elastic body is compressed. A damper comprising: a second elastic body that urges the moving member in an axial direction of the moving member. The damper according to any one of claims 1 to 3,
A damper comprising the moving member.

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