JP2011043222A - Electric brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric brake device having high reliability in strength, which can be constituted inexpensively. <P>SOLUTION: The electric brake device EMB includes a reaction force receiving portion which receives a reaction force in the axial direction from a piston 14 at three or more plurality of contact portions on a flat surface perpendicular to the axial line. A swing permitting mechanism SM which has a conical surface 23d having an axial direction of the piston 14 as a center line, and a spherical surface 41a slidably brought in contact with the conical surface 23d, and which permits the swing relative to a brake caliper 12 of the piston 14 is provided between the piston 14 and the reaction force receiving portion. The diameter of a circle formed by contact between the conical surface 23d and the spherical surface 41a is set smaller than the diameter of a circle inscribed in a polygon formed by connecting a plurality of contact portions of the reaction force receiving portions. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electric brake device, and in particular, a brake caliper assembled to a support, an electric motor and a piston assembled to the brake caliper, and the electric motor interposed between the electric motor and the piston. A rotation-linear motion converting mechanism that converts the rotation of the piston into an axial movement of the piston, and a braking member that is pushed by the axial movement of the piston to brake the braked member, and the axial direction from the piston The present invention relates to an electric brake device including a reaction force receiving portion that receives a reaction force at a plurality of three or more contact points on a plane perpendicular to the axis.

  This type of electric brake device is described in, for example, Patent Document 1 below, and a spherical contact portion slidable between the piston and the reaction force receiving portion (lamp plate of a ball ramp mechanism) has an annular belt shape. The piston can be tilted with respect to a screw shaft that moves the piston in the axial direction (that is, the piston can swing with respect to the brake caliper). For this reason, at the time of braking, the piston can be slid and tilted at the ring-shaped spherical contact portion following the bending of the brake caliper and the uneven wear of the braking member (brake pad). It is possible to press the (brake pad lining) uniformly against the member to be braked (disk rotor).

JP 2004-176773 A

  In the electric brake device described in Patent Document 1 described above, the outermost diameter of the spherical contact portion is a circle inscribed in a polygon formed by connecting a plurality of contact points of the reaction force receiving portion. It is set larger than the diameter. For this reason, if the piston tilts in a state where sliding at the spherical contact portion is hindered by wear or the like, the piston partially lifts at the spherical contact portion, and the piston The spherical contact portion engages with the spherical contact portion at one point of the outermost diameter. As a result, floating occurs at some of the plurality of contact points of the reaction force receiving portion, and the axial reaction force from the piston is accurately distributed to the plurality of contact points of the reaction force receiving portion. There is a possibility that a problem in strength may occur in the reaction force receiving portion.

  The present invention has been made to solve the above-described problems, and includes a brake caliper assembled to a support, an electric motor and a piston assembled to the brake caliper, and an interposition between the electric motor and the piston. And a rotation-linear motion conversion mechanism that converts the rotation of the electric motor into an axial movement of the piston, and a braking member that is pushed by the axial movement of the piston to brake the braked member. An electric brake device including a reaction force receiving portion that receives a reaction force in an axial direction from a piston at a plurality of three or more contact points on a plane substantially perpendicular to the axis, the piston and the reaction force Between the receiving portions, there is a conical surface whose center line is the axial direction of the piston, and a spherical surface that slidably contacts the conical surface, and the brake of the piston A swinging motion allowing mechanism that allows a swinging motion to the caliper, and a diameter of a circle formed by contact between the conical surface and the spherical surface connects a plurality of contact points of the reaction force receiving portion. It is characterized by being set smaller than the diameter of a circle inscribed in the formed polygon.

  In this case, the polygon may be a polygon formed by linking outermost portions at a plurality of contact locations of the reaction force receiving portion, and may be formed at a plurality of contact locations of the reaction force receiving portion. A polygon formed by connecting the innermost portions is desirable.

  In the electric brake device according to the present invention, the rotation of the electric motor is converted into the axial movement of the piston by the rotation-linear motion conversion mechanism. For this reason, by rotating the electric motor, the piston can be moved in the axial direction, and the braking member can be pushed by the piston in the axial direction of the piston. It is possible to brake the member.

  In addition, a conical surface having a center line in the axial direction of the piston and a spherical surface slidably contacting the conical surface are provided between the piston and the reaction force receiving portion. A swing motion permission mechanism that allows a swing motion to the brake caliper is provided. For this reason, when the contact portion (ring-shaped contact portion) between the conical surface and the spherical surface is slidable, at the time of braking, following the bending of the brake caliper and the uneven wear of the braking member, The piston can be slid and tilted at an annular contact portion, and the braking member can be uniformly pressed against the member to be braked.

  By the way, in the electric brake device according to the present invention, the diameter of the circle formed by the contact between the conical surface and the spherical surface is within the polygon formed by connecting a plurality of contact points of the reaction force receiving portion. It is set smaller than the diameter of the circle in contact. For this reason, in the unlikely event that sliding at the contact portion (annular contact portion) between the conical surface and the spherical surface is hindered by wear or the like, the piston is tilted and the piston is circular. Even if the piston floats partially at the ring-shaped contact portion and the piston engages with the contact portion at one point of the contact portion, the location where the piston engages with the contact portion is Inside the polygon formed by connecting a plurality of contact points of the reaction force receiving portion, the contact points of the reaction force receiving portion do not float due to the axial reaction force from the piston . Therefore, even in such a state, the axial reaction force from the piston is accurately distributed to the plurality of contact points of the reaction force receiving portion, and the strength reliability is increased.

  Further, in the electric brake device according to the present invention, the reaction force receiving portions that receive the axial reaction force from the piston are set at a plurality of three or more contact points on a plane substantially perpendicular to the piston axis. . Further, the swinging motion allowing mechanism provided between the piston and the reaction force receiving portion has a conical surface whose center line is the axial direction of the piston, and a spherical surface that slidably contacts the conical surface. Thus, the conical surface and the spherical surface are slidably in contact with each other at the ring-shaped contact portion. For this reason, it is possible to accurately disperse the axial reaction force from the piston, and compared with the case where the portion that receives the axial reaction force from the piston is a single point of contact, the member strength of that part is reduced. It can be low and can be inexpensive.

It is principal part sectional drawing which shows one Embodiment of the electric brake device by this invention. It is a disassembled perspective view of the rotation wedge (rotation-linear motion conversion mechanism) in the electric brake device shown in FIG. A polygon (triangle) formed by connecting the outermost portions at the three contact points (rollers) of the reaction force receiving portion in the rotary wedge (rotation-linear motion conversion mechanism) shown in FIGS. 1 and 2; It is the figure which showed the relationship between the circle | round | yen inscribed in this, and the circle | round | yen formed by the contact of the conical surface and spherical surface of FIG. It is the figure which showed the relationship between the 40 contact location (needle) of the reaction force receiving part in the thrust needle bearing shown in FIG. 1, and the circle formed by the contact of the conical surface and spherical surface of FIG. A polygon (triangle) formed by connecting the detection parts (three contact points of the reaction force receiving part) in the load sensor shown in FIG. 1, a circle inscribed therein, and the conical surface of FIG. It is the figure which showed the relationship with the circle | round | yen formed by contact of a spherical surface. It is the figure which showed the structure of the abrasion compensation mechanism in the electric brake device shown in FIG. 1 from the outer side.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The electric brake device according to the present invention shown in FIGS. 1 to 6 is a disc brake device for a vehicle, and this electric brake device EMB is assembled to an axle hub (rotating body not shown) and a wheel (not shown). A disk rotor 11 that rotates integrally with the brake rotor 12, a brake caliper 12 disposed so as to straddle a part of the outer periphery of the disk rotor 11, an electric motor 13 and a piston 14 that are assembled to the brake caliper 12. ing.

  The electric brake device EMB includes a rotary wedge 20 as a rotation-linear motion conversion mechanism interposed between the electric motor 13 and the piston 14, and a cycloid reducer 30 interposed between the rotary wedge 20 and the electric motor 13. , A swing motion allowing mechanism SM and a wear compensating mechanism 40 interposed between the rotary wedge 20 and the piston 14 are provided, and these are assembled in the brake caliper 12.

  The electric brake device EMB includes an inner brake pad 15 interposed between the disk rotor 11 and the piston 14, and an outer brake pad 16 interposed between the disk rotor 11 and the arm portion 12 a of the brake caliper 12. Yes. The disc rotor 11 can be clamped by the lining 15a of the inner brake pad 15 and the lining 16a of the outer brake pad 16, and is clamped by the lining 15a of the inner brake pad 15 and the lining 16a of the outer brake pad 16 during braking. Thus, the rotation is braked (braking force is generated).

  As shown in FIG. 1, the brake caliper 12 is formed in a shape straddling a part of the outer periphery of the disc rotor 11, and has the above-described arm portion 12a and a cylinder portion 12b. Further, it is assembled to a vehicle body (support) (not shown) via a mounting 17 and is assembled to the mounting 17 so as to be movable in the rotor axial direction (parallel to the axial direction of the piston 14). ing.

  The electric motor 13 is integrally assembled with the cylinder portion 12b of the brake caliper 12 by the case 13a, and rotates according to the operation amount (depression amount or depression force) of a brake pedal (not shown) as is well known. The driving is controlled by an electric control device (not shown). The electric motor 13 is coupled to the input member 31 of the cycloid reduction gear 30 through the output shaft 13b so as to be able to transmit power.

  The piston 14 is formed in a cup shape and assembled together with a return spring 18 (a compression coil spring that urges the piston 14 in the axial direction toward the electric motor 13) in the cylinder portion 12 b of the brake caliper 12. Thus, it can be moved in an axial direction parallel to the axis of the disk rotor 11 and can be swung (movable along the rotor axial direction and can be swung with respect to the brake caliper 12).

  The piston 14 has a guide groove 14 a extending in the axial direction on the outer periphery thereof, and is allowed to move in the axial direction by a guide pin 19 and is restricted from rotating. The guide pin 19 is detachably assembled to the brake caliper 12, and is slidably engaged with the guide groove 14a at the tip. Further, the piston 14 has a notch 14 b at an end portion that protrudes outside the cylinder portion 12 b of the brake caliper 12.

  For this reason, the piston 14 can be rotated with respect to the brake caliper 12 by using a tool (not shown) that engages with the notch 14b in a state where the guide pin 19 is detached from the brake caliper 12. The piston 14 can be moved into the cylinder portion 12b of the brake caliper 12 by the rotation of the piston 14 (the piston 14 can be returned to the initial position shown in FIG. 1 after the pad replacement). The piston 14 is rotated with respect to an output member 42 (annular adjustment screw) of a wear compensation mechanism 40 described later.

  The rotary wedge 20 converts the rotation of the electric motor 13 into the axial movement of the piston 14 (linear movement or linear movement), and is assembled together with the cycloid reducer 30 and the holder 51 in the cylinder portion 12 b of the brake caliper 12. It has been. Further, as shown in FIGS. 1 and 2, the rotating wedge 20 includes a rotating member 21, three sets of rolling elements 22, and a linearly moving member 23, and an annular shape that rotatably supports each rolling element 22. The support plate 24 is provided.

  The rotating member 21 has a rotating cam 21 a that engages with each rolling element 22, and a cylindrical portion 21 b that penetrates the support plate 24 and the linearly moving member 23. A radial needle is attached to the output shaft 13 b of the electric motor 13. The bearing 61 is rotatably assembled. The rotating member 21 is connected to the output member 32 of the cycloid reduction gear 30 via the key 71 so as to be able to transmit power, and rotates integrally with the output member 32 of the cycloid reduction gear 30.

  Each rolling element 22 is constituted by a pair of rollers arranged coaxially as shown in FIGS. 1 to 3, and is arranged at equal intervals (120 degree intervals) in the circumferential direction. The support plate 24 is assembled so as to be rotatable around a radial axis (around a support shaft arranged in the radial direction). The linear motion member 23 has a rotating cam 23 a that engages with each rolling element 22, and an arcuate stopper projection 23 b that defines an initial position and an amount of rotation of the rotational member 21 with respect to the linear motion member 23. In addition, the key groove 23c (see FIG. 2) formed on the outer periphery is assembled to the holder 51 via the key 72 so as not to rotate and to be movable in the axial direction (see FIG. 1). The arc-shaped stopper protrusion 23b is provided so as to be engageable and disengageable with a fan-shaped stopper protrusion 21bo (see FIG. 2) formed on the cylindrical portion 21b of the rotating member 21.

  The cycloid reducer 30 is known per se, and decelerates the rotation of the output shaft 13 b in the electric motor 13 and transmits it to the rotating member 21 of the rotary wedge 20, and includes an input member 31 and an output member 32. ing. The input member 31 has a protrusion 31 a that engages with an engaging portion 51 a provided on the holder 51, and is assembled to the eccentric shaft portion 13 b 1 of the output shaft 13 b of the electric motor 13 via a radial needle bearing 62. Yes. The output member 32 is disposed on the outer periphery of the input member 31 and is rotatably assembled to the holder 51 via a radial ball bearing 63 and a thrust needle bearing 64 (see FIGS. 1 and 4).

  The holder 51 is assembled to the cylinder portion 12b of the brake caliper 12 via the key 73 so as not to rotate and to move in the axial direction of the piston 14, and a radial needle bearing 65 is attached to the output shaft 13b of the electric motor 13. Is assembled through. Further, as shown in FIGS. 1 and 5, three load sensors 52 are assembled to the holder 51. Each load sensor 52 detects an axial reaction force (corresponding to a braking force) from the piston 14 during braking and outputs it to an electric control device (not shown) that controls the rotational drive of the electric motor 13. Yes, they are arranged at equal intervals (at intervals of 120 degrees) in the circumferential direction around the central axis of the piston 14, and are in contact with the case 13a of the electric motor 13 at the tip (detection unit).

  On the other hand, the swing motion permission mechanism SM allows the swing motion of the piston 14 with respect to the brake caliper 12, and is slidable on the conical surface 23d having the center axis of the piston 14 as the center line and the conical surface 23d. And a spherical surface 41a in contact with. The conical surface 23 d is formed on the inner peripheral portion of the linear motion member 23 in the rotary wedge 20. The spherical surface 41 a is formed on the inner peripheral portion of the input member 41 in the wear compensation mechanism 40. Note that the center line of the conical surface 23d only needs to coincide with the axial direction of the piston 14, and does not need to coincide with the center axis of the piston 14 (it may be parallel to the center axis of the piston 14).

  When the lining 15a of the inner brake pad 15 and the lining 16a of the outer brake pad 16 wear, the wear compensation mechanism 40 intermittently moves the piston 14 toward the disk rotor 11 by a predetermined amount according to the wear amount of the lining. As shown in FIGS. 1 and 6, an input member 41, an output member 42, a lever 43, and a torsion spring 44 are provided.

  As shown in FIG. 1, the input member 41 has the above-described spherical surface 41 a and an annular friction engagement surface 41 b on the left side of the intermediate portion, and the cylindrical portion 21 b in the rotating member 21 of the rotary wedge 20. It arrange | positions so that relative rotation is possible with respect to the outer periphery. The input member 41 is connected to the cylindrical portion 21b of the rotating member 21 of the rotating wedge 20 via the connecting pin 49 and the return torsion spring 48, and is directly connected to the rotating wedge 20 via the key 74 at the outer peripheral portion thereof. The moving member 23 is integrally connected to the moving member 23 so as to be movable in the axial direction, and cannot be rotated with respect to the brake caliper 12. The linear motion member 23 is formed with a key groove 23e for the key 74 as shown in FIG.

  The return torsion spring 48 is locked at one end by a connecting pin 49 fixed to the input member 41, and the other end is locked at a notch 21 b 4 (see FIG. 2) formed in the cylindrical portion 21 b of the rotating member 21. The member 21 is urged to rotate toward the initial position (non-braking position). For this reason, when the rotating member 21 of the rotary wedge 20 is rotated from the initial position by the electric motor 13 to be in a braking state, the return torsion spring 48 is twisted to increase the spring force. Therefore, the rotating member 21 of the rotating wedge 20 in the braking state can be turned off by turning the output shaft 13b freely by cutting off the electric power to the electric motor 13, or the initial position (non-braking position) by the return torsion spring 48. It is possible to return to

  As shown in FIGS. 1 and 6, the output member 42 is an annular adjustment screw, has a large number of ratchet teeth 42a on the entire inner circumference, and has male threads 42b on the outer circumference. The right side surface can be frictionally engaged with the friction engagement surface 41 b of the input member 41. Each ratchet tooth 42a is for rotating the output member 42 in the clockwise direction of FIG. 6 by the lever 43, and the claw 43a of the lever 43 can be engaged and disengaged. The male screw 42b is screwed to the female screw 14c formed on the inner periphery of the piston 14 so as to be able to advance and retreat in the axial direction, and the output member 42 rotates in the clockwise direction of FIG. The illustrated piston 14 is configured to move in the axial direction toward the outside of the cylinder portion 12b of the brake caliper 12 (moves toward the disc rotor 11).

  As shown in FIG. 6, the lever 43 has the above-described claw 43a, and also has a locking projection 43b, a long hole 43c, and an engagement projection 43d. As shown in FIG. 6, the long hole 43 c is formed in a shape that is long in the vertical direction (the radial direction of the output member 42), and the lever 43 is connected to the lever support pin 45 fixed to the input member 41. The long hole 43c is assembled so as to be movable in the longitudinal direction and rotatable around the pin. The engaging protrusion 43d protrudes toward the inner periphery, and selectively engages / disengages from the first pushing protrusion 21b1 and the second pushing protrusion 21b2 provided on the cylindrical portion 21b of the rotating member 21 of the rotary wedge 20. It is possible.

  As shown in FIG. 6, the torsion spring 44 is assembled to a spring support pin 46 fixed to the input member 41 at the intermediate portion, locked to the input member 41 at the proximal end, and at the distal end portion. The lever 43 is engaged with the locking projection 43 b. The torsion spring 44 always urges the locking projection 43b of the lever 43 toward the upper side in FIG. 6 (the radially outward direction of the output member 42), and the first pushing projection 21b1 and the second pushing motion described above. The movement of the lever 43 is controlled by the protrusion 21b2.

  In this embodiment configured as described above, the electric motor 13 is rotationally driven in the braking direction (the direction in which the rotating member 21 (cylinder portion 21b) of the rotating wedge 20 is rotationally driven in the clockwise direction in FIG. 6). Then, the rotational driving force is transmitted from the output shaft 13 b of the electric motor 13 to the rotating member 21 of the rotating wedge 20 via the cycloid reduction gear 30, and the linearly moving member 23 of the rotating wedge 20 moves toward the disk rotor 11 and the piston 14. Move in the direction of the axis.

  For this reason, the piston 14 is pushed toward the disk rotor 11 from the linear motion member 23 of the rotary wedge 20 via the input member 41 and the output member 42 of the wear compensation mechanism 40, and the brake caliper 12 is caused by the reaction force. It moves in the opposite direction to the piston 14. As a result, the disc rotor 11 is sandwiched and braked by the lining 15a of the inner brake pad 15 and the lining 16a of the outer brake pad 16. At the time of braking, the input member 41 and the output member 42 of the wear compensation mechanism 40 move integrally with the frictional engagement force therebetween, and the output member 42 does not rotate. Further, when the linings 15a and 16a are worn by braking, the piston 14 is intermittently projected toward the disk rotor 11 by a predetermined amount according to the wear amount of the linings 15a and 16a by the wear compensation mechanism 40. Since the operation is not directly related to the present invention, the description thereof is omitted.

  Further, at the time of braking, the axial reaction force from the piston 14 is transmitted from the output member 42 of the wear compensation mechanism 40 to the input member 41, and the conical surface of the linear motion member 23 in the rotary wedge 20 from the spherical surface 41 a of the input member 41. It is transmitted to 23d. Further, the axial reaction force from the piston 14 is transmitted from the linear motion member 23 of the rotating wedge 20 to the output member 32 of the cycloid reduction gear 30 via each rolling element (roller) 22 and the rotation member 21, and further the cycloidal deceleration. It is transmitted from the output member 32 of the machine 30 to each load sensor 52 through the thrust needle bearing 64 and the holder 51 and is received by the case 13 a of the electric motor 13.

  In this embodiment, a conical surface 23d having a center line in the axial direction of the piston 14 and a spherical surface 41a slidably contacting the conical surface 23d are provided between the rotary wedge 20 and the piston 14. In addition, a swing motion permission mechanism SM that allows a swing motion of the piston 14 relative to the brake caliper 12 is interposed. For this reason, when the contact portion (ring-shaped contact portion) between the conical surface 23d and the spherical surface 41a is slidable, the brake caliper 12 is deflected and the linings 15a and 16a (braking members) are biased during braking. Following the wear, the piston 14 can be slid by the ring-shaped contact portion and tilted, and the linings 15a and 16a (braking members) are uniformly pressed against the disk rotor 11 (braking member). Is possible.

  By the way, in this embodiment, as shown in FIG. 3, the diameter of the circle Cc formed by the contact between the conical surface 23 d and the spherical surface 41 a is a plurality of contacts of the reaction force receiving portion in the rotary wedge 20. Polygons formed by connecting the outermost portions at the locations (the linear contact locations between the rolling elements 22 and the rotating member 21 and the linear contact locations between the rolling elements 22 and the linear motion members 23) (see triangles in FIG. 3) Is set to be smaller than the diameter of the circle C1 inscribed therein.

  As shown in FIG. 4, the diameter of the circle Cc formed by the contact between the conical surface 23d and the spherical surface 41a described above is such that the contact points (40 Smaller than the diameter of a circle C2 inscribed in a polygon (40-sided) formed by connecting the innermost portions of the needle and the output member 32 and the linear contact portion of the 40 needles and the holder 51). Is set.

  Further, as shown in FIG. 5, the diameter of the circle Cc formed by the contact between the conical surface 23 d and the spherical surface 41 a described above is a point-like contact between the tip of each load sensor 52 and the case 13 a of the electric motor 13. It is set smaller than the diameter of a circle C3 that is inscribed in a polygon (see the triangle in FIG. 5) formed by connecting the locations (a plurality of contact locations of the reaction force receiving portion).

  For this reason, in the unlikely event that sliding at the contact portion (annular contact portion) between the conical surface 23d and the spherical surface 41a is hindered by wear or the like, the piston 14 tilts and the piston 14 becomes a circle. Even if the piston 14 is partially lifted at the ring-shaped contact portion and the piston 14 is engaged with the contact portion at one point of the contact portion, the position where the piston 14 is engaged with the contact portion is described above. The inside of the polygon formed by connecting a plurality of contact points of each reaction force receiving portion, and the plurality of contact points of the reaction force receiving portion are floated by an axial reaction force from the piston 14. There is no. Therefore, even in such a state, the axial reaction force from the piston 14 is accurately distributed to a plurality of contact points of the reaction force receiving portion, and the strength reliability is increased.

  In this embodiment, the reaction force receiving portions that receive the axial reaction force from the piston 14 are set at a plurality of three or more contact locations on a plane perpendicular to the axis of the piston 14. Further, the swing motion allowing mechanism SM provided between the piston 14 and the reaction force receiving portion includes a conical surface 23d whose center line is the axial direction of the piston 14, and a spherical surface that is slidably in contact with the conical surface 23d. 41a, and the conical surface 23d and the spherical surface 41a are slidably in contact with each other at an annular linear contact portion. For this reason, it is possible to disperse | distribute the axial direction reaction force from the piston 14 exactly, and compared with the case where the part which receives the axial direction reaction force from the piston 14 is a contact in one point, the member of the part The strength can be reduced and the cost can be reduced.

  In the above-described embodiment, the diameter of the circle Cc formed by the contact between the conical surface 23d and the spherical surface 41a is formed by connecting the outermost portions at a plurality of contact points of the reaction force receiving portion in the rotary wedge 20. The diameter of the circle C1 inscribed in the polygon, the diameter of the circle C2 inscribed in the polygon formed by connecting the innermost portions at the plurality of contact points of the reaction force receiving portion in the thrust needle bearing 64, Although it was carried out by setting it to be smaller than the diameter of the circle C3 inscribed in the polygon formed by connecting the point-like contact points between the tip of the load sensor 52 and the case 13a of the electric motor 13, The diameter of the circle formed by the contact between the conical surface and the spherical surface only needs to be smaller than the diameter of the circle inscribed in the polygon formed by connecting a plurality of contact points of each reaction force receiving portion. Each It is also possible to carry out set to be smaller than the diameter of the circle inscribed in the polygon formed by connecting the innermost of the plurality of contact points of the nest. In this case, the axial reaction force from the piston can be more accurately dispersed, and the strength reliability is further increased.

  In the above-described embodiment, as shown in FIGS. 3 to 5, the reaction force receiving portion in the rotary wedge 20, the reaction force receiving portion in the thrust needle bearing 64, the load sensors 52, the electric motor 13, and the like. In all of the reaction force receiving portions, the diameter of the circle Cc formed by the contact between the conical surface 23d and the spherical surface 41a is formed by connecting a plurality of contact points of each reaction force receiving portion. Although it was carried out by setting it to be smaller than the diameter of a circle inscribed in the square, the circle Cc formed by the contact between the conical surface 23d and the spherical surface 41a in at least one of the reaction force receiving portions described above. It is also possible to carry out by setting the diameter to be smaller than the diameter of a circle inscribed in a polygon formed by connecting a plurality of contact points of the reaction force receiving portion.

  In the embodiment described above, the electric brake is provided with a load sensor 52 that detects an axial reaction force from the piston 14 during braking and outputs it to an electric control device (not shown) that controls the rotational drive of the electric motor 13. Although the present invention is implemented in the device EMB, the present invention is also applied to an electric brake device that does not include such a load sensor 52 (in this case, the braking force is estimated by the amount of current flowing to the electric motor). It is possible to carry out similarly or appropriately.

EMB: Electric brake device, 11: Disc rotor (braking member), 12: Brake caliper, 13 ... Electric motor, 14 ... Piston, 15 ... Inner brake pad, 15a ... Inner brake pad lining (braking member), DESCRIPTION OF SYMBOLS 16 ... Outer side brake pad, 16a ... Outer side brake pad lining (braking member), 17 ... Mounting, 20 ... Rotation wedge (rotation-linear motion conversion mechanism), 22 ... Rolling element (roller), 30 ... Cycloid speed reducer , SM: Swing motion permissible mechanism, 23d: conical surface, 41a: spherical surface, 52: load sensor, 64: thrust needle bearing, Cc: circle formed by contact between conical surface and spherical surface, C1: rotating wedge Inscribed in the polygon formed by connecting the outermost parts at the multiple contact points of the reaction force receiving part C2, a circle inscribed in a polygon formed by connecting innermost portions at a plurality of contact points of the reaction force receiving portion in the thrust needle bearing, C3, a tip portion of each load sensor, and a case of the electric motor A circle inscribed in a polygon formed by connecting point-like contact points

Claims (3)

A brake caliper assembled to the support, an electric motor and a piston assembled to the brake caliper, and interposed between the electric motor and the piston to convert rotation of the electric motor into axial movement of the piston A rotation-linear motion conversion mechanism; and a braking member that is pushed by the axial movement of the piston to brake the braked member, and that the axial reaction force from the piston is on a plane substantially perpendicular to the axis. An electric brake device having reaction force receiving portions that are received at a plurality of three or more contact points,
Between the piston and the reaction force receiving portion, there is a conical surface whose center line is the axial direction of the piston, and a spherical surface that slidably contacts the conical surface, and the brake caliper of the piston It is equipped with a swing motion permission mechanism that allows swing motion against
The diameter of the circle formed by the contact between the conical surface and the spherical surface is set smaller than the diameter of the circle inscribed in the polygon formed by connecting a plurality of contact points of the reaction force receiving portion. An electric brake device characterized by that.   2. The electric brake device according to claim 1, wherein the polygon is a polygon formed by connecting outermost portions at a plurality of contact points of the reaction force receiving portion.   The electric brake device according to claim 1, wherein the polygon is a polygon formed by connecting innermost portions at a plurality of contact points of the reaction force receiving portion.

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