JP5967431B2 - Steering lock device - Google Patents

Description

  The present invention relates to a steering lock device.

Patent Document 1 proposes a steering lock device in which a lock pin is engaged with a lock hole provided in a worm or worm wheel of a speed reducer that decelerates rotation of an electric motor.
Patent Literature 2 proposes a steering lock device that achieves a steering lock by engaging a lock member with a locked body fixed to a side surface of a worm wheel of a reduction gear.

  Patent Document 3 discloses a steering lock device in which a metal core of a worm wheel of a speed reducer has a protrusion that extends across a plane orthogonal to a rotation axis, and locks the protrusion to achieve a steering lock. Proposed.

JP 2003-327082 A JP 2006-168414 A JP 2006-117038 A

Legally, even when the steering is locked, a torque limiter function is added to the steering device so that slippage occurs between the steering shaft and the lock mechanism when a torque exceeding a predetermined value (for example, 100 Nm or more) is applied. Yes.
For example, in Patent Document 1, a sliding bearing (specifically, a tolerance ring) as a torque limiter is interposed between a worm wheel and a steering shaft.

However, tolerance rings have large variations in slip torque (limit torque) due to manufacturing errors. Therefore, it is conceivable to classify the tolerance ring and the parts fitted to it into layers according to dimensional accuracy, and to select and assemble those having good compatibility. In this case, however, it takes time and the manufacturing cost increases.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a steering lock device that can achieve a torque limiter function and achieve a precise limit torque without using a tolerance ring. .

  In order to achieve the above object, the invention of claim 1 is characterized in that a steering shaft (3) to which a steering member (2) is attached and an outer periphery of the steering shaft are fixed so as not to rotate relative to each other, and an engaging recess (42; 142). ) To be locked (30; 130), a lock member (44; 144) displaced to a lock position for engaging with the engagement recess, and a lock release position for releasing from the engagement recess, and the lock member An urging member (45) for urging the lock member to the lock position, and the engagement recess is adapted to cause the lock member to be urged to the urging member when a predetermined rotational torque is applied to the steering shaft. There is provided a steering lock device (10; 110) including a cam surface (51, 52; 151, 152) which is driven against the unlocking position.

In addition, although the alphanumeric character in a parenthesis represents the corresponding component etc. in embodiment mentioned later, this does not mean that this invention should be limited to those embodiment as a matter of course. The same applies hereinafter.
According to a second aspect of the present invention, the urging member includes an urging spring (45), and the actuator (46) drives the lock member to the locked position against the urging spring as the urging member. ) May be provided.

According to a third aspect of the present invention, the engaging recess includes a first cam surface (51; 151) and a second cam surface (52; 152) that are opposed to each other in the rotation direction of the locked body and are inclined in opposite directions. And may be included.
According to a fourth aspect of the present invention, the lock member may include a cam follower surface (61, 62; 161, 162) that can coincide with the cam surface at the lock position.

  Further, as in claim 5, a metal core (30) fixed to the steering shaft so as to be integrally rotatable, and a resin member (32) fixed to the metal core so as to be integrally rotatable and having teeth (31) on the outer periphery. And a driven gear (27; 127) to which the power of the steering assist electric motor (19) is transmitted, and the locked body may be constituted by a cored bar of the driven gear.

  According to the first aspect of the invention, in the locked state, when a rotational torque exceeding a predetermined value is applied to the steering shaft, the lock member is driven to the unlocked position by the action of the cam surface of the engaging recess. Therefore, the steering member can be rotated while the lock member is engaged and disengaged from the engagement recess, and a torque limiter function can be realized without using a conventional tolerance ring. Moreover, if it is a cam surface, the inclination angle, surface roughness, etc. can be set as required, and a precise limit torque can be realized.

According to the invention of claim 2, the cam surface according to the steering direction of the steering member engages with the lock member, so that the torque limiter function is activated regardless of the steering direction, and the lock member is unlocked. Can be displaced to a position.
According to the invention of claim 3, since the cam surface of the engaging recess coincides with the cam follower surface of the locking member at the locking position, the rotational force of the steering shaft necessary for releasing the locking member from the engaging recess. Can be set with high accuracy.

  According to the invention of claim 4, since the locked body for providing the engaging recess is constituted by the cored bar of the driven gear, the structure can be simplified.

1 is a schematic cross-sectional view showing a schematic configuration of an electric power steering device to which a steering lock device of an embodiment of the present invention is applied. It is the schematic of a steering lock apparatus, and has shown the lock release state. It is the schematic of a steering lock apparatus, and has shown the locked state. It is sectional drawing of the principal part of the electric power steering apparatus with which the steering lock apparatus of another embodiment of this invention was applied. It is a partially broken plan view of the worm wheel periphery of the embodiment of FIG. It is a partially broken schematic diagram of the steering lock device of the embodiment of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of an electric power steering apparatus including a steering lock apparatus according to an embodiment of the present invention.
Referring to FIG. 1, an electric power steering apparatus 1 is connected to a steering shaft 3 to which a steering member 2 such as a steering wheel is attached, and the steering shaft 3 via a universal joint 4, an intermediate shaft 5 and a universal joint 6. A steering mechanism 8 including a rack and pinion mechanism 7, a steering assist mechanism 9 that applies a steering assist force to the steering shaft 3, and a steering lock device 10 that prohibits the rotation of the steering shaft 3 are provided.

The rack and pinion mechanism 7 includes a pinion shaft 11 connected to the intermediate shaft 5 via a universal joint 6, and a rack shaft 12 that meshes with the pinion shaft 11 and serves as a steered shaft extending in the left-right direction (axial direction) of the automobile. I have. A pinion 11 a provided near the end of the pinion shaft 11 meshes with the rack 12 a of the rack shaft 12.
The rack shaft 12 is supported in a rack housing 13 fixed to the vehicle body through a plurality of bearings (not shown) so as to be capable of linear reciprocation. Both end portions of the rack shaft 12 protrude to both sides of the rack housing 13 and are connected to corresponding steered wheels 15 via tie rods 14 and knuckle arms (not shown), respectively. The steered mechanism 8 includes a rack and pinion mechanism 7, a tie rod 14, a knuckle arm, and steered wheels 15.

  The steering shaft 3 has a first steering shaft 16 that can rotate integrally with the steering member 2, a second steering shaft 17 connected to the intermediate shaft 5, and the first steering shaft 16 and the second steering shaft 17 on the same axis. And a torsion bar 18 connected to transmit torque. When the steering member 2 is operated to rotate the first steering shaft 16, this rotation is converted into a linear motion of the rack shaft 12 by the pinion 11a and the rack 12a. Thereby, the turning of the steered wheel 15 is achieved.

The steering assist mechanism 9 includes an electric motor 19 for assisting steering, and a speed reduction mechanism 20 including a worm gear mechanism that decelerates the rotation of the electric motor 19 and transmits it to the second steering shaft 17.
The housing 21 that supports the steering shaft 3 is made of, for example, an aluminum alloy, and is attached to a vehicle body (not shown). The housing 21 includes a first housing 22 (corresponding to a sensor housing) and a second housing 23 (corresponding to a gear housing) fitted together.

The first housing 22 accommodates a torque sensor 24 that detects a steering torque applied to the steering shaft 3 via the steering member 2, a control board 25 on which a control circuit that controls the operation of the electric motor 19 is mounted. Yes. The second housing 23 accommodates the speed reduction mechanism 20.
The reduction mechanism 20 includes a worm 26 as a drive gear connected to a rotating shaft (not shown) of the electric motor 19 via a joint (not shown), and a driven gear (reduction gear) that meshes with the worm 26. And a worm wheel 27.

  The worm wheel 27 is held at an intermediate portion in the axial direction of the second steering shaft 17 so as to be integrally rotatable and immovable in the axial direction. The second steering shaft 17 is rotatably supported by a first bearing 28 held by the first housing 22 and a second bearing 29 held by the second housing 23. The first bearing 28 and the second bearing 29 are disposed on both sides of the worm wheel 27 in the axial direction.

The worm wheel 27 is fixed to the second steering shaft 17 of the steering shaft 3 so as to be integrally rotatable, and to the outer periphery of the core metal (locked body 30) so as to be integrally rotatable. And an annular resin member 32 having teeth 31 formed on the outer periphery.
The steering lock device 10 is constituted by a core metal of the worm wheel 27, and includes a locked body 30 having an annular convex portion 41 protruding from one end surface, and an annular convex portion 41 of the locked body 30 as shown in FIG. The outer periphery 41a is provided with a plurality of engaging recesses 42 arranged at equal intervals in the circumferential direction X1 and opened radially outward.

  Further, the steering lock device 10 has a lock position (see FIG. 3) for engaging with the engagement recess 42 and a lock release position (see FIG. 2) that is disengaged from the engagement recess 42 around the pivot shaft 43 supported by the housing 21. A lock arm 44 as a lock member supported so as to be swingable, a biasing spring 45 as a biasing member that biases the lock arm 44 to the lock position, and against the biasing spring 45, And a solenoid 46 as an actuator for driving the lock arm 44 to the unlocked position.

  The pivot shaft 43 is disposed between the first end 44 a and the second end 44 b of the lock arm 44. The biasing spring 45 is composed of, for example, a torsion coil spring wound around the pivot shaft 43. The solenoid 46 includes a main body 46a fixed to the housing 21 and a movable iron core 46b that moves forward and backward from the main body 46a by the action of an exciting coil (not shown) housed in the main body 46a.

  The distal end of the movable iron core 46b is connected to the first end 44a of the lock arm 44 (lock member). Specifically, the connecting pin 47 provided at the tip of the movable iron core 46 b can slide in the longitudinal direction of the connecting groove 48 in the connecting groove 48 formed of a long groove provided in the first end portion 44 a of the lock member 44. Is engaged. An engagement convex portion 49 that engages with the engagement concave portion 42 is provided at the second end portion 44 b of the lock arm 44.

  When the excitation coil of the solenoid 46 is energized by an ON signal from a control unit (not shown), the movable iron core 46b moves backward by the electromagnetic force of the solenoid 46, and the lock arm 44 is moved against the biasing spring 45 in FIG. As shown, the engaging convex portion 49 is displaced to the unlocking position where the engaging convex portion 49 is disengaged from the engaging concave portion 42. As a result, the rotation of the worm wheel 27 and thus the rotation of the steering shaft 3 is allowed.

On the other hand, when the excitation of the solenoid 46 is released and the electromagnetic force of the solenoid 46 is turned off, the lock arm 44 urged by the urging spring 45 engages the engaging projection 49 as shown in FIG. It is displaced to a lock position for engaging with the mating recess 42. As a result, the rotation of the worm wheel 27 and consequently the rotation of the steering shaft 3 is locked.
In the locked state shown in FIG. 3, each engagement recess 42 is in a direction in which the engagement protrusion 49 of the lock arm 44 is detached from the engagement recess 42 when a rotational torque greater than a predetermined value is applied to the steering shaft 3. As cam surfaces to be driven, a first cam surface 51 and a second cam surface 52 are provided. The first cam surface 51 and the second cam surface 52 are respectively provided on a pair of inner wall surfaces facing the circumferential direction X1 (rotation direction) in the engagement recess 42.

  As shown in FIG. 2, the first cam surface 51 and the second cam surface 52 of the engaging recess 42 are expanded in the circumferential direction X1 and separated from the radial direction Y1 toward the outer side in the radial direction Y1. Are inclined in opposite directions. On the other hand, the engaging projection 49 of the lock arm 44 includes a first cam follower surface 61 that is parallel to the first cam surface 51 at the lock position, and a second cam follower surface 62 that is parallel to the second cam surface 52 at the lock position. have. Depending on the steering direction, one of the first cam surface 51 and the second cam surface 52 coincides with the corresponding cam follower surface 61 or 62.

  According to the present embodiment, the cam surface (first cam surface 51 or second cam surface 52) of the engagement recess 42 is acted upon when a predetermined torque or more is applied to the steering shaft 3 in the locked state. The lock arm 44 as a lock member is driven to the unlock position. Therefore, the steering member 2 can be rotated while the lock arm 44 is engaged and disengaged from the engagement recess 42, and a torque limiter function can be realized without using a conventional tolerance ring. Moreover, if it is a cam surface (the 1st cam surface 51 and the 2nd cam surface 52), the inclination angle, surface roughness, etc. can be set as required, and a precise limit torque can be implement | achieved.

Further, since the first cam surface 51 and the second cam surface 52 facing the circumferential direction X1 are provided as cam surfaces, the cam surface (first cam surface or second cam surface 52 corresponding to the steering direction of the steering member 2 is provided. However, by engaging with the lock arm 44, the lock arm 44 can be displaced to the unlock position by using the torque limiter function regardless of the steering direction.
In the locked position, the cam surface of the engaging recess 42 coincides with the corresponding cam follower surface of the lock arm 44. That is, according to the steering direction, the first cam surface 51 is engaged with the first cam follower surface 61 of the lock arm 44 (see FIG. 3) or the second cam surface 52 is the second cam follower surface. Since the engagement (not shown) coincides with 62, the rotational force of the steering shaft 3 required to disengage the lock arm 44 from the engagement recess 42 can be set with high accuracy.

Moreover, since the to-be-locked body 30 for providing the engagement recessed part 42 is comprised with the metal core of the driven gear (worm wheel 27), a structure can be simplified.
4 to 6 show another embodiment of the present invention. The present embodiment is mainly different from the embodiment of FIGS.
That is, in the embodiment of FIGS. 1 to 3, the plurality of engagement recesses 42 are provided on the outer periphery 41 a of the annular protrusion 41 of the locked body 30. However, in the steering lock device 110 of this embodiment, FIG. As shown in FIG. 5, in the locked body 130 made of the core metal of the worm wheel 127, a plurality of engagements are made not on the outer periphery 141 a of the annular convex portion 141 of the locked body 130 but on the end surface 141 b of the annular convex portion 141. A recess 142 is provided. As shown in FIG. 5, the engagement recesses 142 are arranged at equal intervals in the circumferential direction X1, and are recessed in the axial direction Z1, as shown in FIG.

  As shown in FIG. 6, the first cam surface 151 and the second cam surface 152 of the engaging recess 142 expand and separate in the circumferential direction X1 toward the one side (lock arm 144 side) in the axial direction Z1. Further, they are inclined in opposite directions with respect to the axial direction Z1. On the other hand, the engagement projection 149 of the lock arm 144 includes a first cam follower surface 161 that is parallel to the first cam surface 151 at the lock position, and a second cam follower surface 162 that is parallel to the second cam surface 152 at the lock position. have.

  In the constituent elements of the present embodiment, the same constituent elements as those of the embodiments of FIGS. 1 to 3 are denoted by the same reference numerals as those of the constituent elements of the embodiments of FIGS. Also in the present embodiment, as in the embodiments of FIGS. 1 to 3, a torque limiter function can be realized without using a tolerance ring, and an accurate limit torque can be realized. In the present embodiment, the annular convex portion 141 may be eliminated and an engaging concave portion may be provided on the end surface of the cored bar (locked body 130).

The present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, the body to be locked 30; 130 is configured by the core metal of the worm wheel 27; 127. The body 30; 130 may be provided separately from the worm wheel and fixed to the steering shaft 3 (second steering shaft 17) so as to be integrally rotatable.
In the embodiment, the biasing member that biases the lock member (lock arm 44; 144) to the lock position is the bias spring 45, and drives the lock member (lock arm 44; 144) to the unlock position. The actuator is the solenoid 46, but instead of this, a solenoid may be used as the biasing member, and a biasing spring may be used as the actuator.

  Further, the lock arm as the lock member may be eliminated, and the movable iron core may function as the lock member by providing an engagement convex portion that engages with the engagement concave portion of the locked body at the tip of the movable iron core of the solenoid. . In addition, various modifications can be made within the scope of the claims of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Electric power steering device, 2 ... Steering member, 3 ... Steering shaft, 8 ... Steering mechanism, 9 ... Steering assist mechanism, 10; 110 ... Steering lock device, 16 ... 1st steering shaft, 17 ... 2nd steering shaft , 19 ... Electric motor, 20 ... Deceleration mechanism, 26 ... Worm (drive gear), 27; 127 ... Worm wheel (driven gear), 30; 130 ... Locked body (core metal), 41; 42; 142 ... engaging recess, 43 ... pivot shaft, 44; 144 ... lock arm (lock member), 45 ... biasing spring (biasing member), 46 ... solenoid, 46a ... main body, 46b ... movable iron core, 47 ... Connection pin, 48 ... Connection groove, 49; 149 ... Engagement projection, 51; 151 ... First cam surface, 52; 152 ... Second cam surface, 61; 161 ... First cam follower surface, 62; 162 ... Second cam Orowa surface, X1 ... circumferential direction, Y1 ... radially, Z1 ... axial

Claims (5)

A steering shaft with a steering member attached thereto;
A locked body fixed to the outer periphery of the steering shaft so as not to be relatively rotatable and having an engaging recess;
A lock member that is displaced to a lock position that engages with the engagement recess and a lock release position that disengages from the engagement recess;
A biasing member that biases the lock member to the lock position,
The engaging recess includes a cam surface that includes a cam surface that drives the lock member to the unlocked position against the biasing member when a predetermined rotational torque is applied to the steering shaft. The biasing member according to claim 1, wherein the biasing member includes a spring,
A steering lock device comprising an actuator that drives the lock member to a lock position against a spring as the biasing member. 3. The steering lock device according to claim 1, wherein the engagement recess includes a first cam surface and a second cam surface that are opposed to each other in a rotational direction of the locked body and are inclined in opposite directions.   4. The steering lock device according to claim 1, wherein the lock member includes a cam follower surface that can coincide with the cam surface at the lock position. 5. 5. The steering assist device according to claim 1, comprising: a cored bar fixed to the steering shaft so as to be integrally rotatable; and a resin member fixed to the cored bar so as to be integrally rotatable and having teeth on an outer periphery thereof. A driven gear to which the power of the electric motor is transmitted,
The locked body is a steering lock device configured by a cored bar of the driven gear.

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