JP2006112476A - Motor-driven brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a caliper body further compact, by reducing an incorporating dimension of a motor, a speed reduction mechanism and a motion converting mechanism incorporated into the caliper body, in both directions of the radial direction and the longitudinal direction. <P>SOLUTION: In an electric motor 4, a stator 4a is fixed to the outer peripheral side of a ball screw mechanism 6 as the motion converting mechanism, and a rotor 4b is rotated around the ball screw mechanism 6. By juxtaposing a marvellous planetary gear speed reduction mechanism 5 as the speed reduction mechanism in the shaft direction with the electric motor 4 on the outer peripheral side of the ball screw mechanism 6, the incorporating dimension of the electric motor 4, the marvellous planetary gear speed reduction mechanism 5 and the ball screw mechanism 6, is reduced in both directions of the radial direction and the longitudinal direction, and the caliper body 1 can be made further compact. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electric brake device that converts a rotational force of an electric motor into a linear motion and presses a brake member against a member to be braked.

  Although many hydraulic brake devices have been adopted as a vehicle brake device, in recent years, with the introduction of advanced brake control such as ABS (Antilock Brake System), these controls can be performed without complicated hydraulic circuits. Electric brake devices that can be designed compactly are drawing attention. An electric brake device is provided with a motion conversion mechanism such as a ball screw mechanism that operates an electric motor in response to a brake pedal depression signal or the like and converts the rotational force of the electric motor into a linear motion. In many cases, a speed reduction mechanism such as a gear speed reduction mechanism is provided so that a large braking force can be obtained with a small-capacity electric motor.

  Usually, since an electric brake device is attached under the spring of a vehicle, many electric motors, a speed reduction mechanism, and a motion conversion mechanism are incorporated in a caliper body together with a brake member so as to be easily attached to the vehicle. In order to make the caliper body compact, an electric motor in which the stator is fixed to the caliper body on the outer peripheral side of the motion conversion mechanism and the rotor is rotated around the motion conversion mechanism is adopted ( For example, see Patent Documents 1 and 2).

JP 2002-48170 A JP 2003-247576 A

  In the one described in Patent Document 1, a planetary gear speed reduction mechanism as a speed reduction mechanism is disposed on the outer peripheral side of a ball ramp mechanism or a ball screw mechanism as a motion conversion mechanism, and a rotor and a stator of an electric motor are further provided on the outer peripheral side. Is arranged. For this reason, this electric brake device has a problem that the outer diameter dimension of the caliper body becomes large.

  On the other hand, in what is described in Patent Document 2, a planetary gear speed reduction mechanism as a speed reduction mechanism is disposed on the shaft end side of a ball screw mechanism as a motion conversion mechanism, and a rotor of an electric motor is disposed on the outer peripheral side of the ball screw mechanism. A stator is arranged. For this reason, in this case, the length dimension of the caliper body is increased.

  Therefore, an object of the present invention is to further reduce the size of the caliper body by reducing the assembly dimensions of the electric motor, the speed reduction mechanism, and the motion conversion mechanism incorporated in the caliper body in both the radial direction and the length direction.

  In order to solve the above problems, the present invention provides an electric motor, a speed reduction mechanism for reducing the rotation of the electric motor, and a motion for converting the rotational motion of the electric motor decelerated by the speed reduction mechanism into a linear motion of the linear motion member. In the electric brake device that incorporates the conversion mechanism into the caliper body and presses the brake member against the member to be braked by the linear motion of the linear motion member, the stator is fixed on the outer peripheral side of the motion conversion mechanism, A configuration is adopted in which the rotor rotates around the motion conversion mechanism, and the speed reduction mechanism is arranged side by side with the electric motor on the outer peripheral side of the motion conversion mechanism.

  That is, in the electric motor, the stator is fixed on the outer peripheral side of the motion conversion mechanism, the rotor rotates around the motion conversion mechanism, and the speed reduction mechanism is arranged side by side with the electric motor on the outer peripheral side of the motion conversion mechanism. As a result, the assembly dimensions of the electric motor, the speed reduction mechanism, and the motion conversion mechanism are reduced in both the radial direction and the length direction so that the caliper body can be made more compact.

  The input shaft and output shaft of the speed reduction mechanism are compactly arranged by wrapping the input shaft and output shaft of the speed reduction mechanism in the axial direction and interposing at least one bearing between the input shaft and the output shaft. Can do.

  By using a needle roller bearing as the bearing interposed between the input shaft and the output shaft, the assembly dimension can be further reduced in the radial direction.

  A planetary gear reduction mechanism can be adopted as the reduction mechanism.

  By using the planetary gear reduction mechanism as a mysterious planetary gear reduction mechanism, the reduction ratio can be increased and the electric motor can have a smaller capacity.

  By making the motion conversion mechanism a ball screw mechanism, conversion loss in the motion conversion mechanism can be reduced.

  By providing a linear motion one-way clutch that allows the linear motion of the linear motion member in the forward direction to press the brake member but prevents it in the reverse direction, even if the brake member is worn, The moving member can always be held near the pressed position of the brake member, and the brake member wear compensation mechanism can be incorporated without impairing the compact design.

  In the electric brake device of the present invention, the electric motor is configured such that the stator is fixed on the outer peripheral side of the motion converting mechanism, the rotor rotates around the motion converting mechanism, and the speed reducing mechanism is operated on the outer peripheral side of the motion converting mechanism. Therefore, the caliper body can be made more compact by reducing the assembly dimensions of the electric motor, the speed reduction mechanism, and the motion conversion mechanism in both the radial direction and the length direction.

  The input shaft and output shaft of the speed reduction mechanism are compactly arranged by wrapping the input shaft and output shaft of the speed reduction mechanism in the axial direction and interposing at least one bearing between the input shaft and the output shaft. Can do.

  By using a needle roller bearing as the bearing interposed between the input shaft and the output shaft, the assembly dimension can be further reduced in the radial direction.

  By adopting a planetary gear speed reduction mechanism as the speed reduction mechanism and using the planetary gear speed reduction mechanism as a mysterious planetary gear speed reduction mechanism, the reduction ratio can be increased and the electric motor can have a smaller capacity.

  By making the motion conversion mechanism a ball screw mechanism, conversion loss in the motion conversion mechanism can be reduced.

  By providing a linear motion one-way clutch that allows the linear motion of the linear motion member in the forward direction to press the brake member, but prevents it in the backward direction, the linear motion after braking even if the brake member is worn. The member can always be held near the pressing position of the brake member, and the brake member wear compensation mechanism can be incorporated without impairing the compact design.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, this electric brake device is a disc brake in which brake pads 3 as brake members are disposed opposite to both sides of a disc rotor 2 as a braked member inside a caliper body 1. 1 is incorporated with an electric motor 4, a mysterious planetary gear speed reduction mechanism 5 as a speed reduction mechanism, and a ball screw mechanism 6 as a motion conversion mechanism. The brake pad 3 is pressed against the disc rotor 2 via the member 7. The front end side of the cylindrical portion 1 a is sealed with a boot 8 attached between the caliper body 1 and the pressing member 7, and the rear end side is closed with a lid 9.

  In the electric motor 4, the stator 4a is fixed to the cylindrical portion 1a of the caliper body 1 on the outer peripheral side of the ball screw mechanism 6, and the rotor 4b rotates around the ball screw mechanism 6 in the axial direction of the rotor 4b. The extended cylindrical portion is used as the input shaft 10 of the mysterious planetary gear reduction mechanism 5, and the sun gear 11 is provided on the outer peripheral side thereof. The rotor 4b is supported by a ball bearing 12 on a spacer 20 which will be described later, and the portion where the input shaft 10 wraps in the axial direction with a small diameter portion 17b of the output shaft 17 which will be described later. It is supported.

  The mysterious planetary gear speed reduction mechanism 5 is arranged side by side with the electric motor 4 in the axial direction on the outer peripheral side of the ball screw mechanism 6, and is rotatably supported on each of the three shafts 14a attached to the carrier 14 at a phase of 120 °. The pair of planetary gears 15a and 15b thus meshed with the sun gear 11, the planetary gear 15a is meshed with the internal gear 16a fixed to the cylindrical portion 1a, and the planetary gear 15b is output from the mysterious planetary gear reduction mechanism 5. It is meshed with an internal gear 16 b provided on the shaft 17.

  The output shaft 17 has a double cylindrical shape having a large diameter portion 17a and a small diameter portion 17b. An internal gear 16b is provided on the inner peripheral surface of the large diameter portion 17a, and the inner peripheral surface of the small diameter portion 17b. The nut 6b of the ball screw mechanism 6 is connected, and a collar 18 is press-fitted to the axial rear end side. Further, the output shaft 17 is supported by the caliper body 1 by a ball bearing 19, and the rear end is abutted against a spacer 20 press-fitted into the outer peripheral surface of the collar 18, so that the axial position is regulated. The spacer 20 is rotatably supported by the lid 9 by a ball bearing 21 and a thrust bearing 22. The collar 18 may be integrated with the output shaft 17 or the spacer 20.

  In the mysterious planetary gear reduction mechanism 5, the reduction ratio is determined by the difference in the number of teeth between the internal gear 16a and the internal gear 16b, and a large reduction ratio can be obtained as compared with the ordinary planetary gear reduction mechanism. The rotation of the rotor 4b of the electric motor 4 is transmitted from the input shaft 10 provided with the output to the output shaft 17 provided with the internal gear 16b. The pair of planetary gears 15a and 15b may be integrated.

  The ball screw mechanism 6 is formed by screwing a nut 6b to a screw shaft 6a via a ball 6c, and pressing the rotational movement of the nut 6b connected to the output shaft 17 to transmit the rotation with a bolt 23. This is converted into a linear motion of the screw shaft 6a connected to the member 7 and prevented from rotating by the key 24.

  As shown in FIG. 2, a bolt 25 is screwed to the rear end of the screw shaft 6a, and a retaining ring member 26 as a linear motion one-way clutch is attached to a stepped portion 25a provided on the bolt 25. ing. As shown in FIG. 3, the retaining ring member 26 is annular and has a cutting portion 26 a at one place on the circumference. Also, holes 26b are provided on both sides of the cutting portion 26a so as to hook the claw of the tool so as to reduce the diameter and remove it from the inner peripheral surface of the collar 18 when replacing the brake pad 3 described later.

  As shown in FIGS. 2 (a) and 2 (b), the retaining ring member 26 has an inner peripheral edge that is not in contact with the stepped portion 25a of the bolt 25 and is rotatable around the stepped portion 25a, and is bent to the outer periphery. A portion 26c is provided so that the outer peripheral edge comes into contact with the inner peripheral surface of the collar 18 at an angle inclined so as to protrude toward the opposite side of the forward direction of the screw shaft 6a. Allow movement in the forward direction but prevent it in the backward direction.

  At the time of braking in which the screw shaft 6a moves forward, as shown in FIG. 2A, the retaining ring member 26 abuts against the head of the bolt 25 while rotating following the collar 18, and together with the screw shaft 6a. Move in the forward direction. Further, at the time of releasing the brake when the rotation of the electric motor 4 is stopped, as shown in FIG. 2B, when the screw shaft 6a is retracted by the amount of play of the ball screw mechanism 6, the retaining ring member 26 follows the stepped portion 25a. Thus, the screw shaft 6a moves relative to the rear end side and is locked to the rear end surface of the screw shaft 6a to prevent the screw shaft 6a from further retracting. For this reason, since the screw shaft 6a after braking is allowed to be slightly retracted by a gap in the axial direction of the attachment of the retaining ring member 26 corresponding to the length of the stepped portion 25a, the brake at the time of non-braking is performed. There is no dragging of the pad 3.

  As described above, this electric brake device rotates the electric motor 4 in one direction at the time of braking, and only stops the electric motor 4 at the time of releasing the brake, to the inner peripheral surface of the collar 18 of the retaining ring member 26. The engagement position moves naturally forward with the progress of wear of the brake pad 3 during braking, and naturally changes so that the standby position of the screw shaft 6a after braking moves forward. FIG. 4 shows a state in which the brake pad 3 is worn, and the screw shaft 6a and the retaining ring member 26 have moved considerably forward due to the accumulation of forward movement little by little.

  Next, a method for replacing the worn brake pad 3 will be described. As shown in FIG. 4, with the screw shaft 6a and the retaining ring member 26 moved considerably forward, as shown in FIG. 5, after removing the lid 9 from the caliper body 1, the retaining ring member 26 is removed with a tool. The diameter is reduced and removed from the inner peripheral surface of the collar 18. After that, the electric motor 4 is reversely rotated to retract the screw shaft 6a to the initial position, and the brake pad 3 is replaced with a new one.

  In the embodiment described above, the mysterious planetary gear speed reduction mechanism is employed as the speed reduction mechanism, and the ball screw mechanism is employed as the motion conversion mechanism. However, these speed reduction mechanisms and motion conversion mechanisms are not limited to those of the embodiment. As the speed reduction mechanism, other planetary gear speed reduction mechanisms or the like can be adopted, and as the motion conversion mechanism, a ball ramp mechanism or the like can be adopted.

A longitudinal sectional view showing an embodiment of an electric brake device a and b are cross-sectional views showing enlarged main parts of FIG. The top view which shows the retaining ring member of FIG. 1 is a longitudinal sectional view showing a state where the brake pad of FIG. 1 is worn FIG. 4 is a longitudinal sectional view for explaining a method of replacing the worn brake pad in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Caliper body 1a Cylindrical part 2 Disc rotor 3 Brake pad 4 Electric motor 4a Stator 4b Rotor 5 Strange planetary gear reduction mechanism 6 Ball screw mechanism 6a Screw shaft 6b Nut 6c Ball 7 Press member 8 Boot 9 Lid 10 Input shaft 11 Sun gear 12 Ball bearing 13 Needle roller bearing 14 Carrier 14a Shafts 15a, 15b Planetary gears 16a, 16b Internal gear 17 Output shaft 17a Large diameter portion 17b Small diameter portion 18 Collar 19 Ball bearing 20 Spacer 21 Ball bearing 22 Thrust bearing 23 Bolt 24 Key 25 Bolt 25a Stepped portion 26 Retaining ring member 26a Cutting portion 26b Hole 26c Bending portion

Claims (7)

  An electric motor, a speed reduction mechanism that decelerates rotation of the electric motor, and a motion conversion mechanism that converts the rotational motion of the electric motor decelerated by the speed reduction mechanism into linear motion of the linear motion member are incorporated in the caliper body, and the linear motion member In the electric brake device that presses the brake member against the member to be braked by linear motion of the motor, the electric motor is fixed on the outer peripheral side of the motion conversion mechanism, and the rotor rotates around the motion conversion mechanism. An electric brake device characterized in that the speed reduction mechanism is arranged side by side with the electric motor on the outer peripheral side of the motion conversion mechanism.   The electric brake device according to claim 1, wherein an input shaft and an output shaft of the speed reduction mechanism are wrapped in an axial direction, and at least one bearing is interposed between the input shaft and the output shaft.   The electric brake device according to claim 2, wherein the bearing interposed between the input shaft and the output shaft is a needle roller bearing.   The electric brake device according to any one of claims 1 to 3, wherein the speed reduction mechanism is a planetary gear speed reduction mechanism.   The electric brake device according to claim 4, wherein the planetary gear reduction mechanism is a mysterious planetary gear reduction mechanism.   The electric brake device according to any one of claims 1 to 5, wherein the motion conversion mechanism is a ball screw mechanism.   The electric type according to any one of claims 1 to 6, further comprising a linear motion one-way clutch that allows linear motion of the linear motion member in a forward direction in which the brake member is pressed, but prevents the linear motion in a backward direction. Brake device.

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