JP2015232368A - Electric linear motion actuator and electric brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a cost of an electric linear motion actuator having a lock function which locks a slide member by engaging a lock pin with a lock hole formed at a side part of a gear of a gear speed reducer.SOLUTION: A lock mechanism which can lock and unlock the rotation of a rotor shaft 25 of an electric motor 24 is formed of: a plurality of lock holes 62 which are formed at one side of one gear 33 out of a plurality of gears forming a gear speed reduction mechanism 30; lock pins 63 which are retractably arranged at the lock holes 62, and lock the gear 33 while being engaged with the lock holes 62 at forward movement; and a linear solenoid 64 which makes the lock pins 63 advance and retract. The lock holes 62 are formed at a lock member 61 as a part different from the gear 33, thereby enabling forging and pressing processing of the lock holes 62, to reduce a cost.

Description

  The present invention relates to an electric linear actuator that linearly drives a driven member such as a brake pad, and an electric brake device using the electric linear actuator.

  As an electric linear actuator using an electric motor as a drive source, one described in Patent Document 1 has been conventionally known. In the electric linear actuator described in Patent Document 1, the rotation of the rotor shaft of the electric motor is decelerated by a gear reducer and input to the rotation shaft, and the rotation of the rotation shaft is converted by a rotation / linear motion conversion mechanism. It is converted into a linear motion of a slide member provided so as to be movable in the axial direction along the inner diameter surface of the housing, and the slide member is moved in the axial direction.

  Further, a plurality of locking holes are provided at intervals on one pitch circle centered on the rotation axis of the gear on the side surface of one gear in the gear reducer, with respect to one point on the pitch circle. A lock pin provided so as to be able to advance and retreat is advanced by a linear solenoid, and the slide member is locked at an arbitrary position moved in the axial direction by engagement of the lock pin with one locking hole.

  By adopting the electric linear actuator with the above configuration in the electric brake device, when parking, the brake pad that is moved forward by the slide member presses the disc rotor with the specified pressing force to lock the brake pad. Thus, the vehicle can be held in a stopped state, and an electric brake device having a parking brake function can be obtained.

JP 2012-87889 A

  By the way, in the electric linear actuator described in Patent Document 1, since the locking hole is directly provided in the gear, if the locking hole is provided by forging or sintering, the accuracy of the gear is affected. Become. For this reason, it is necessary to form the locking hole by cutting, and it takes time and effort to process, and there is a point to be improved in reducing the cost.

  Here, when the lock pin is engaged with the locking hole, the rotational force in the braking release direction is applied to the gear by the reaction force (reaction force of the braking force) from the disc rotor and the brake pad after the electric power to the electric motor is cut off. Is done. At this time, when the rotational torque is applied to the engaging portion between the locking hole and the lock pin and the strength is insufficient, the engaging portion is deformed. In order to improve the durability at the engaging portion, it is effective to increase the pitch circle diameter for forming the locking hole. However, since the locking hole is provided directly in the gear, the pitch circle diameter is set to the gear. The outer diameter cannot be larger than the outer diameter. For this reason, the durability at the engaging portion between the lock pin and the locking hole cannot be significantly increased, and there is still a point to be improved in improving the durability.

  An object of the present invention is to provide a lock that engages a lock pin with an engaging portion such as an engaging hole provided on a side portion of a gear of a gear reducer to lock the slide member at an arbitrary position moved in the axial direction. This is to reduce the cost of the electric linear actuator having a function and to improve the durability at the engaging portion of the lock pin.

  In order to solve the above problems, in the electric linear actuator according to the present invention, an electric motor, a gear reduction mechanism that decelerates and outputs the rotation of the rotor shaft of the electric motor, and an output gear of the gear reduction mechanism A slide member that is movable in the axial direction by rotation of the motor, a rotation / linear motion conversion mechanism that converts the rotational motion of the output gear into a linear motion in the axial direction of the slide member, and the rotation of the rotor shaft of the electric motor. A locking mechanism that can be locked and unlocked, and the locking mechanism includes a plurality of locking portions provided in one of a plurality of gears forming a gear reduction mechanism, and the locking portions An electric linear motion comprising a lock pin that engages with the engaging portion during forward movement and locks the gear, and a pin drive actuator that moves the lock pin forward and backward. In the actuator, the locking portion is formed on a locking member that is a separate part from the gear, and the locking member is provided on one side of the gear so as to be integrally rotatable by a detent means. .

  In the electric brake device according to the present invention, the brake pad is linearly driven by the electric linear actuator, and the disc rotor is pressed by the brake pad to apply a braking force to the disc rotor. In the type brake device, the electric linear actuator is composed of the electric linear actuator described above according to the present invention, and the brake pad is linearly driven by the slide member of the electric linear actuator.

  In the electric brake device having the above configuration, when the electric motor of the electric linear actuator is driven, the rotation of the rotor shaft of the electric motor is reduced by the gear reduction mechanism and output from the output gear, and the rotation of the output gear Is converted into a linear motion of the slide member by a rotation / linear motion conversion mechanism. For this reason, the slide member moves forward, the brake pad coupled to the slide member is pressed against the disc rotor, and the disc rotor is braked.

  When parking, press the brake pad against the disc rotor and apply the braking force necessary for parking to the disc rotor as described above. The lock pin is engaged with the locking portion of the locking member that rotates in the forward direction to lock the gear. In the locked state of the gear, the energization to the electric motor is cut off to suppress wasteful consumption of electric energy.

  Here, by forming the locking portion with which the lock pin is engaged in the locking member which is a separate component from the gear, a forging or press working method can be adopted for forming the locking portion. The part can be formed very easily.

  Further, by providing the locking member with the locking portion, the locking portion can be provided on the pitch circle on the outer diameter side of the gear. In this case, when the disc rotor is braked, the gear rotates in the braking release direction due to the reaction force of the braking force, and when the pressing force is applied to the engaging portion of the locking portion and the lock pin, the pressing force is The pitch circle diameter can be reduced by the increased radius ratio, and the durability at the engaging portion can be improved.

  In the electric linear actuator according to the present invention, the detent means may be a detent in which a locking member is spline-fitted to a boss portion provided in the gear, or may be a key stop.

  In the electric linear actuator according to the present invention, the lock pin is engaged and disengaged, and the engaging portion that locks the gear when engaged is formed in the engaging member as a separate part from the gear, thereby forming the engaging portion. In addition, forging or pressing can be employed, and the locking portion can be formed very easily, thereby reducing the cost.

  In addition, since the locking portion on which the lock pin is engaged and disengaged can be provided on the large-diameter pitch circle on the outer diameter side of the gear, when the disk rotor is braked, the gear is released in the braking release direction by the reaction force of the braking force The pressing force applied to the engaging portion of the locking portion and the lock pin by rotating can be reduced by the radius ratio obtained by increasing the pitch circle diameter, and the durability at the engaging portion can be improved. .

A longitudinal sectional view showing an embodiment of an electric linear actuator according to the present invention Sectional view along the line II-II in FIG. Sectional view along line III-III in FIG. Sectional drawing which expands and shows a part of gear reduction mechanism shown in FIG. (A) is a cross-sectional view taken along the line V-V in FIG. 4, and (b) is a cross-sectional view taken along the line bb in (a). (C) is a front view which shows the other example of a locking member, (d) is sectional drawing along the dd line of (c). A longitudinal sectional view showing an embodiment of an electric brake device according to the present invention

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 7 shows an electric brake device in which the electric linear actuator A according to the present invention is employed. In this electric brake device, a caliper 11 is provided on the outer periphery of a disc rotor 10 that rotates integrally with a wheel, and a claw portion that axially faces the outer peripheral portion of the outer side surface of the disc rotor 10 at one end portion of the caliper 11. 12 and the claw portion 12 supports the outer brake pad 13.

  Further, an inner brake pad 14 is disposed opposite to the outer peripheral portion of the inner side surface of the disk rotor 10, and the inner brake pad 14 is attached to the disk rotor 10 by an electric linear actuator A provided on the other side of the caliper 11. I try to move it.

  A mount 17 is provided on the outer peripheral portion of the inner side surface of the disk rotor 10. The mount 17 is fixedly supported by a knuckle (not shown). As shown in FIG. 2, a pair of opposed pin support pieces 18 are provided on both sides of the mount 17, and slide pins 19 extending in a direction orthogonal to the disk rotor 10 are provided at the respective ends of the pin support pieces 18. The caliper 11 is slidably supported by each of the slide pins 19.

  Although not shown in detail in the figure, the mount 17 is supported so as to be movable toward the disc rotor 10 in a state in which each of the outer brake pad 13 and the inner brake pad 14 is non-rotatable. doing.

  As shown in FIG. 1, the electric linear actuator A has a housing 20. The housing 20 is integrally provided with the caliper 11 shown in FIG. 7 and has a cylindrical shape, and an outer ring member 21 as a slide member is slidably incorporated therein.

  A base plate 22 is provided at one end of the housing 20 outward in the radial direction, and an outer surface of the base plate 22 and one end opening of the housing 20 are covered with a cover 23.

  An electric motor 24 is supported on the base plate 22, and the rotation of the rotor shaft 25 of the electric motor 24 is reduced and output by a gear reduction mechanism 30 incorporated in the cover 23.

As shown in FIGS. 1 and 2, the gear reduction mechanism 30, the rotation of the input gear 31 attached to a rotor shaft 25 of the electric motor 24 sequentially decelerated by the primary reduction gear train G ₁ to tertiary reduction gear train G ₃ The rotation of the output gear 32 is converted into a linear motion of the outer ring member 21 by the rotation / linear motion conversion mechanism 40 shown in FIG.

  The rotation / linear motion conversion mechanism 40 supports the output gear 32 at its shaft end, and arranges a rotation shaft 41 that rotates integrally with the output gear 32 on the axis of the outer ring member 21. A planetary roller 42 is incorporated between the outer ring member 21 and a spiral groove 44 that meshes with a spiral protrusion 43 having a V-shaped cross section provided on the inner periphery of the outer ring member 21 is formed on the outer periphery of the planetary roller 42. The rotation of the shaft 41 causes the planetary roller 42 to rotate and revolve, thereby causing the outer ring member 21 to linearly move in the axial direction.

  Here, the spiral groove 44 formed on the outer periphery of the planetary roller 42 has the same pitch as that of the spiral protrusion 43 provided on the inner periphery of the outer ring member 21, and the pitch is the same. However, instead of the spiral groove 44, a plurality of circumferential grooves may be formed at the same pitch as the spiral ridge 43.

  The rotating shaft 41 is inserted into a boss portion 46 formed at the center of a bearing member 45 incorporated in one end portion of the housing 20, and is rotatable by a plurality of rolling bearings 47 incorporated in the boss portion 46. It is supported. On the other hand, the bearing member 45 is prevented from moving toward the one end opening side of the housing 20 by a stopper ring 48 attached to the inner periphery of one end portion of the housing 20.

  As shown in FIG. 3, a plurality of planetary rollers 42 are arranged at intervals in the circumferential direction. Each planetary roller 42 is in rolling contact with the outer periphery of the rotating shaft 41 and the inner periphery of the outer ring member 21. The outer periphery of the rotating shaft 41 is a cylindrical surface. When the rotating shaft 41 rotates, the planetary roller 42 revolves around the rotating shaft 41 while rotating around the roller shaft 53. That is, the planetary roller 42 rotates by the rotational force received from the outer periphery of the rotating shaft 41, and accordingly, the planetary roller 42 rolls around the inner periphery of the outer ring member 21 and revolves.

  The planetary roller 42 is rotatably supported by a carrier 50 incorporated between the rotating shaft 41 and the outer ring member 21. The carrier 50 has a pair of opposed disks 51a and 51b supported rotatably about the rotation shaft 41 at both axial ends, and a pair of shaft insertions facing the pair of disks 51a and 51b in the axial direction. A plurality of holes 52 are formed at intervals in the circumferential direction, and both end portions of the roller shaft 53 are inserted into each of the plurality of shaft insertion holes 52, and the planetary roller 42 is rotatably supported by each of the roller shafts 53. ing.

  The shaft insertion hole 52 is a long hole in the radial direction. Each of the plurality of roller shafts 53 is supported by the shaft insertion hole 52 so as to be movable in the radial direction, and penetrates the pair of disks 51a and 51b. Elastic rings 54 are stretched around both ends of the roller shaft 53 facing the outside. The elastic ring 54 is stretched over both end portions of the roller shaft 53 in a state where the diameter is expanded, and an elastic force in the diameter reducing direction is applied, and the planetary roller 42 is pressed against the outer diameter surface of the rotating shaft 41 by the elastic force. ing.

  Among the pair of disks 51 a and 51 b, a thrust plate 55 is incorporated between the inner side disk 51 b positioned on the bearing member 45 side and the facing portion of the bearing member 45, and a thrust bearing 56 is interposed between the thrust plate 55 and the bearing member 45. Is incorporated.

  As shown in FIG. 1, the opening at the other end located outside the other end opening of the housing 20 of the outer ring member 21 is closed by attaching a seal cover 57 to prevent foreign matter from entering the inside.

  One end of a bellows 58 is connected to the other end opening of the housing 20, and the other end of the bellows 58 is connected to the other end of the outer ring member 21. Intrusion is prevented.

  As shown in FIG. 1, the gear reduction mechanism 30 is provided with a lock mechanism 60 that can lock and unlock the rotor shaft 25 of the electric motor 24.

As shown in FIGS. 1, 4 and 5, the lock mechanism 60 has a disk-like shape formed on one side of the intermediate gear 33 on the output side in the secondary reduction gear train G ₂ , which is a separate part from the intermediate gear 33. A locking member 61 is provided on one side of the intermediate gear 33 so as to be integrally rotatable, and a plurality of locking holes 62 as locking portions are formed in the locking member 61 at equal intervals on the same circle. A lock pin 63 provided so as to be able to advance and retreat with respect to one point on the pitch circle of the locking hole 62 is advanced and retracted by a linear solenoid 64 serving as a pin driving actuator. The gear 33 is locked.

Here, the intermediate gear 33 and the engagement member 61, the fitting by serration 65 is fitted to the boss portion 34a provided at the intermediate gear 34 on the input side in the three primary reduction gear train G ₃ is prevented from rotating, boss The stopper ring 66 is attached to the outer periphery of the end portion 34a and is prevented from being pulled out. By the serration fitting of the serration 65, the intermediate gear 33 and the locking member 61 are provided so as to be integrally rotatable. Here, serration fitting by serration 65 has been described as a means for preventing rotation of intermediate gear 33 and locking member 61, but the invention is not limited to this, and spline fitting or rotation by keying may be used.

  The locking member 61 is a forged product, and a locking hole 62 is formed during manufacturing by the forging. The locking hole 62 has an arcuate shape, and one of the end faces opposed in the circumferential direction is a tapered surface 62a that guides the lock pin 63 in the backward movement direction.

  The locking member 61 may be formed by sintering, or may be formed by press forming a metal plate as shown in FIGS. 6 (c) and 6 (d). That is, a plate material made of a material such as SPCC is punched into a circular shape by press molding, and at the same time, a plurality of locking holes 62 are punched and formed at equal circumferences. Further, when the locking hole 62 is formed, a part thereof is bent to form the cylindrical portion and the tapered surface 62a. If the locking member 61 is formed consistently by press molding, the molding becomes low-cost and environmentally friendly.

  The linear solenoid 64 and the lock pin 63 constitute an assembly unit U. The assembly unit U is disposed between the housing 20 and the electric motor 24 and attached to the base plate 22 as shown in FIG.

  The electric linear actuator A shown in the embodiment has the above-described structure. In the electric linear actuator A, the inner brake pad 14 is attached to the disc rotor 10 by an outer ring member 21 as shown in FIG. It is trying to drive straight.

  When the electric motor 24 shown in FIG. 1 is driven when the electric linear actuator A is used in the electric brake device as shown in FIG. 7, the rotation of the rotor shaft 25 of the electric motor 24 is caused by the gear reduction mechanism 30. The speed is reduced and output from the output gear 32 to the rotary shaft 41, and the rotary shaft 41 rotates at a reduced speed.

  Since the outer diameter surfaces of the plurality of planetary rollers 42 are in elastic contact with the outer diameter surface of the rotating shaft 41, the planetary roller 42 rotates due to contact friction with the rotating shaft 41 due to the rotation of the rotating shaft 41. While revolving.

  At this time, since the spiral groove 44 formed on the outer diameter surface of the planetary roller 42 meshes with the spiral protrusion 43 provided on the inner diameter surface of the outer ring member 21, the engagement between the spiral groove 44 and the spiral protrusion 43 is increased. As a result, the outer ring member 21 moves in the axial direction, and the inner ring brake pad 14 is linearly pressed and moved toward the disk rotor 10 by the outer ring member 21, and the disk rotor 10 is pressed by the inner side brake pad 14. Is done. The caliper 11 moves toward the direction in which the outer brake pad 13 attached to the claw portion 12 approaches the disc rotor 10 by the reaction force of the pressing force, and the outer brake pad 13 contacts the disc rotor 10. The outer brake pad 13 strongly clamps the outer periphery of the disk rotor 10 from both sides in the axial direction with the inner brake pad 14, and a braking force is applied to the disk rotor 10.

  At the time of parking, as described above, the lock pin 63 is moved forward by the operation of the linear solenoid 64 in a state where a braking force is applied so that the outer brake pad 13 and the inner brake pad 14 hold the disc rotor 10 (FIG. 1). reference).

  When the lock pin 63 moves forward, if one of the plurality of locking holes 62 faces the lock pin 63, the lock pin 63 is locked to the locking hole 62 as shown in FIGS. 5 (a) and 5 (b). The pin 63 is engaged, and the engagement member 61 and the intermediate gear 33 that rotates together with the engagement member 61 are locked by the engagement.

  Here, when the lock pin 63 moves forward, if there is a phase shift in the circumferential direction between the lock pin 63 and the locking hole 62, the locking pin 63 cannot be engaged with the locking hole 62. In this case, by driving the electric motor 24 with the lock pin 63 moved forward, the intermediate gear 33 is rotated in the braking direction indicated by the one-dot chain line arrow in FIG. 5 so that the locking hole 62 faces the lock pin 63. The intermediate gear 33 is rotated until the lock pin 63 is engaged with the locking hole 62. The engaging member 61 is locked by the engagement, and the serration 65 locks the intermediate gear 33 that can rotate integrally with the engaging member 61. Therefore, the intermediate gear 33 is locked by engaging the lock pin 63 with the locking hole 62.

  When the intermediate gear 33 is locked, the rotor shaft 25 of the electric motor 24 is also locked. Therefore, the energization of the electric motor 24 can be cut off, and wasteful consumption of electric energy can be suppressed. it can.

  In the locked state of the intermediate gear 33 by the engagement of the locking hole 62 and the lock pin 63 as described above, that is, the locked state of the rotor shaft 25 of the electric motor 24, the reaction force from the disk rotor 10 causes the gear reduction mechanism 30 to move. Since the rotational force in the braking release direction is applied to each gear, the end surface of the locking hole 62 facing the tapered surface 62a is in strong contact with the lock pin 63, and the lock pin 63 is held in the engaged state by the contact. Is done. Therefore, the engagement state is maintained by the reaction force even when the energization to the linear solenoid 64 is released.

  Here, when the lock of the rotor shaft 25 in the electric motor 24 is released, the energization of the linear solenoid 64 is already released, so the electric motor 24 is driven and the intermediate gear 33 is driven in the braking direction shown in FIG. , The engagement of the end surface of the locking hole 62 with the lock pin 63 is released, and the taper surface 62a on the other side of the locking hole 62 presses the tip of the lock pin 63 to lock the lock pin 63. It is moved backward to the unlocking position where it comes out of the hole 62.

  As shown in FIGS. 4 and 5, the lock pin 63 is engaged and disengaged, and an engagement hole 62 as an engagement portion for locking the intermediate gear 33 when engaged is provided in an engagement member 61 as a separate part from the intermediate gear 33. By forming, the formation method by the forging, the process by press, or sintering can be employ | adopted for formation of the latching hole 62. FIG. As a result, the locking hole 62 can be formed very easily, and the cost can be reduced.

  4 and 5, the pitch circle of the locking hole 62 is provided on the outer diameter side of the intermediate gear 33 that is larger than the diameter of the intermediate position between the tooth bottom of the intermediate gear 33 and the serration hole. By providing the locking hole 62 in the member 61, although not shown, the locking hole 62 can be provided on a pitch circle having a diameter larger than the outer diameter of the intermediate gear 33, for example. When the disk rotor 10 is braked, the intermediate gear 33 rotates in the braking release direction in response to the reaction force of the braking force, and the pressing force is applied to the engaging portion of the locking hole 62 and the lock pin 63. Can be reduced by the radius ratio obtained by increasing the pitch circle diameter, and the durability at the engaging portion can be improved.

10 Disc rotor 14 Brake pad 21 Outer ring member (slide member)
24 Electric motor 25 Rotor shaft 30 Gear reduction mechanism 32 Output gear 33 Intermediate gear 40 Rotation / linear motion conversion mechanism 60 Lock mechanism 61 Lock member 62 Lock hole (lock portion)
63 Lock pin 64 Linear solenoid (Pin drive actuator)
65 Serration

Claims (4)

Electric motor (24), gear reduction mechanism (30) that decelerates and outputs rotation of rotor shaft (25) of electric motor (24), and rotation of output gear (32) of the gear reduction mechanism (30) A slide member (21) movable in the axial direction by means of a rotary / linear motion conversion mechanism (40) for converting the rotational movement of the output gear (32) into the linear movement of the slide member (21) in the axial direction; And a lock mechanism (60) capable of locking and unlocking the rotation of the rotor shaft (25) of the electric motor (24), and the lock mechanism (60) forms a gear reduction mechanism (30). A plurality of locking portions (62) provided in one gear (33) of the plurality of gears, and the locking portions (62) are provided so as to be able to advance and retreat. 62) to engage and lock the gear (33) And Kkupin (63), the electric linear motion actuator consisting its pin driving actuator for advancing and retracting the lock pin (63) (64),
The locking portion (62) is formed in a locking member (61) which is a separate part from the gear (33), and the locking member (61) is integrally formed on one side of the gear (33) by a rotation preventing means. An electric linear actuator characterized in that it is rotatably provided.   The electric linear actuator according to claim 1, wherein the locking member (61) is a molded product formed by forging or pressing.   The electric linear actuator according to claim 1 or 2, wherein the rotation preventing means is a fitting of a serration (65). An electric type in which the brake pad (14) is linearly driven by an electric linear actuator, and the disc rotor (10) is pressed by the brake pad (14) to apply a braking force to the disc rotor (10). In the brake system,
The electric linear actuator comprises the electric linear actuator according to any one of claims 1 to 3, and the brake pad (14) is linearly driven by a slide member (21) of the electric linear actuator. An electric brake device characterized in that the electric brake device is characterized in that

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