JP5923957B2 - Vehicle steering device and rack guide mechanism - Google Patents

Description

  The present invention relates to a vehicle steering apparatus and a rack guide mechanism that have a rack shaft that moves in the axial direction and a housing that houses the rack shaft, and that guides the movement of the rack shaft.

  The rack guide mechanism of Patent Document 1 includes a rack guide that guides the movement of the rack shaft, an elastic member that presses the rack guide against the rack shaft, and a sheet member that is provided between the rack guide and the rack shaft.

JP 2008-307966 A

  In the rack guide mechanism, the rack guide may move in a direction approaching the rack shaft (rack direction). The main reason why the rack guide moves in the rack direction is wear of the seat member due to contact with the rack shaft and wear of the meshing portion between the rack shaft and the pinion shaft. When the rack guide moves in the rack direction, the force applied by the elastic member to the rack guide decreases, and the force for pressing the rack guide against the rack shaft decreases.

  In order to solve the above-described problems, an object of the present invention is to provide a vehicle steering apparatus and a rack guide mechanism that can suppress a decrease in the force for pressing the rack guide against the rack shaft.

(1) One form of the vehicle steering device according to the present invention is a guide for movement of the rack shaft, a rack shaft that moves in the axial direction, a housing that houses the rack shaft, and approaches the rack shaft. A rack guide that is housed in the housing in a movable state defined by a rack direction that is a direction and an anti-rack direction that is a direction away from the rack shaft, and an end on the anti-rack direction side of the rack guide A threaded portion formed in a portion, and a rotating member that meshes with the threaded portion and moves in the anti-rack direction with respect to the rack guide when rotating in one rotational direction with respect to the rack guide; , with respect to the rotation direction of force by cooperation with the previous SL rack force and the rotating member the rotating member Is intended to impart a pressing member for contact with the rotary member, and the pressing force imparting mechanism having a first elastic member for applying a force acting on the rack direction to the pressing member, wherein in the moving direction rack A second elastic member provided between the guide and the rotating member; and positioned on the side opposite to the rack with respect to the rotating member, and fixed to the housing, and the rotation in the moving direction When the distance from the member is less than a predetermined amount, the rotation of the rotating member relative to the rack guide is restricted. When the distance from the rotating member in the moving direction is equal to or larger than the predetermined amount, the rotation member relative to the rack guide The gist of the present invention is to provide a regulating portion that allows rotation.

According to this invention, the pressing force applying mechanism applies a force in the rack direction to the rotating member, so that the rotating member and the rack guide move in the rack direction. And when the space | interval of the control part in a moving direction of a rack guide and a rotation member becomes less than predetermined amount from less than predetermined amount, control of rotation of the rotation member by a control part is cancelled | released. Then, the pressing force applying mechanism applies a force in one direction of rotation to the rotating member, so that the rotating member rotates and the rotating member engaged with the screw portion is anti-rack direction with respect to the rack guide. Move to. When the rotating member moves in the anti-rack direction, movement of the pressing member in the rack direction is suppressed, and the first elastic member is suppressed from becoming longer in the moving direction. For this reason, compared with the structure in which the first elastic member becomes longer by the amount of movement of the rack guide in the rack direction, the reduction in the force applied from the first elastic member to the pressing member is suppressed, and the rack guide is rack-mounted. It can suppress that the force pressed on a shaft falls.
Further, the second elastic member positioned between the rack guide and the rotating member in the moving direction can be used to apply a force for moving the rotating member in the anti-rack direction with respect to the rack guide. Accordingly, it is possible to assist the movement of the rotating member in the anti-rack direction with respect to the rack guide.

(2) According to one example of the vehicle steering device, the rotating member has a rotation-side regulating portion formed at an end of the rotating member on the side opposite to the rack, and the rotation-side regulating portion is A rotation side inclined surface that is inclined from the rack direction side toward the non-rack direction side as it goes in the one rotation direction, and a rotation side restriction surface that is continuous with the rotation side inclination surface, and the restriction portion includes: A fixed-side inclined surface having a shape corresponding to the rotating-side inclined surface; and a fixed-side restricting surface having a shape corresponding to the rotating-side restricting surface, wherein the fixed-side restricting surface is the fixed-side inclined surface in the moving direction. When the distance between the surface and the rotation-side inclined surface is less than the predetermined amount, the surface contacts the rotation-side regulating surface, and the distance between the fixed-side inclined surface and the rotation-side inclined surface in the moving direction is equal to or greater than the predetermined amount. When the It is the gist of.

(3) According to an example of the vehicle steering apparatus, a plurality of the restriction portions are formed in a circumferential direction along a direction in which the rotating member rotates. According to this invention, the rotation of the rotating member can be restricted a plurality of times before the rotating member makes one rotation.

(4) According to an example of the vehicle steering device, the rotation side restriction portion is formed in a plurality in a circumferential direction along a direction in which the rotation member rotates.

  According to this invention, the rotation-side restriction surface of each of the plurality of rotation-side restriction members is brought into contact with the fixed-side restriction surface of each of the plurality of restriction portions, thereby reliably restricting the rotation of the rotation member. Can do.

( 5 ) According to an example of the vehicle steering device , the vehicle steering device includes a restriction member on which the restriction portion is formed, and further includes an elastic member between the pressing member and the restriction member. Have. According to this invention, the collision between the pressing member and the regulating member can be mitigated.

( 6 ) One form of the rack guide mechanism according to the present invention is a rack guide mechanism that guides the movement of the rack shaft accommodated in the housing in the axial direction, and guides the movement of the rack shaft. A rack guide housed in the housing in a movable state defined by a rack direction that is a direction approaching the shaft and an anti-rack direction that is a direction away from the rack shaft; and the anti-rack direction in the rack guide A threaded portion formed at a side end portion and meshed with the threaded portion, and moves in the anti-rack direction with respect to the rack guide when rotating in one rotational direction with respect to the rack guide. a rotary member, the rotation direction of force by cooperation with the previous SL rack force and the rotating member the Rolling are those given to the member, a pressing member in contact with the rotary member, and the pressing force imparting mechanism having a first elastic member for applying a force acting on the rack direction to the pressing member, wherein A second elastic member provided between the rack guide and the rotating member in the moving direction, and positioned on the side opposite to the rack with respect to the rotating member, and fixed to the housing, When the interval between the rotating member in the moving direction is less than a predetermined amount, the rotation of the rotating member relative to the rack guide is restricted, and when the interval between the rotating member in the moving direction is equal to or greater than the predetermined amount, the rack guide. And a restricting portion that allows rotation of the rotating member with respect to the above.

According to this invention, the pressing force applying mechanism applies a force in the rack direction to the rotating member, so that the rotating member and the rack guide move in the rack direction. And when the space | interval of the control part in a moving direction of a rack guide and a rotation member becomes less than predetermined amount from less than predetermined amount, control of rotation of the rotation member by a control part is cancelled | released. Then, the pressing force applying mechanism applies a force in one direction of rotation to the rotating member, so that the rotating member rotates and the rotating member engaged with the screw portion is anti-rack direction with respect to the rack guide. Move to. When the rotating member moves in the anti-rack direction, movement of the pressing member in the rack direction is suppressed, and the first elastic member is suppressed from becoming longer in the moving direction. For this reason, compared with the structure in which the first elastic member becomes longer by the amount of movement of the rack guide in the rack direction, the reduction in the force applied from the first elastic member to the pressing member is suppressed, and the rack guide is rack-mounted. It can suppress that the force pressed on a shaft falls.
Further, the second elastic member positioned between the rack guide and the rotating member in the moving direction can be used to apply a force for moving the rotating member in the anti-rack direction with respect to the rack guide. Accordingly, it is possible to assist the movement of the rotating member in the anti-rack direction with respect to the rack guide.

  In the present invention, compared with the configuration in which the elastic member becomes longer by the amount of movement of the rack guide in the rack direction, the reduction of the force applied from the elastic member to the pressing member is suppressed, and the force for pressing the rack guide against the rack shaft is reduced. Provided are a vehicle steering device and a rack guide mechanism that can suppress a decrease.

The block diagram which shows typically the whole structure about the steering apparatus for vehicles of embodiment of this invention. Sectional drawing which shows the cross-sectional structure perpendicular | vertical to the axial direction of the rack shaft of FIG. 1 about the rack guide mechanism of embodiment. The perspective view which shows the perspective structure of a rack guide, a thread part, a rotation member, a rotation control member, and a press member about the rack guide mechanism of embodiment. The external view which shows only a rotation member about the rack guide mechanism of embodiment. The external view which shows only a rotation control member about the rack guide mechanism of embodiment. The external view which shows only a press member about the rack guide mechanism of embodiment. The schematic diagram which shows operation | movement of a rotation member, a rotation control member, and a press member about the rack guide mechanism of embodiment. Sectional drawing which shows the state with a small degree of abrasion of a sheet | seat member about the rack guide mechanism of embodiment. Sectional drawing which shows the state with a large abrasion degree of a sheet | seat member about the rack guide mechanism of embodiment.

  FIG. 1 shows a configuration of a vehicle steering apparatus 1 as a column assist type electric power steering apparatus. The vehicle steering device 1 includes a steering shaft 10, a rack shaft 20, an assist device 30, a rack housing 40, a rack and pinion mechanism 1A, a speed reduction mechanism 1B, and a rack guide mechanism 1C.

  A steering wheel 2 is connected to the steering shaft 10. The steering shaft 10 includes a column shaft 11 to which the steering wheel 2 is fixed, a pinion shaft 13 that transmits rotation to the rack and pinion mechanism 1A, and an intermediate shaft 12 that connects the column shaft 11 and the pinion shaft 13. .

  The rack and pinion mechanism 1 </ b> A includes a pinion 14 formed on the pinion shaft 13 and a rack 21 formed on the rack shaft 20. The pinion 14 and the rack 21 are meshed with each other in the rack housing 40. That is, the rack shaft 20 and the pinion shaft 13 mesh with each other, and the rack and pinion mechanism 1A connects the steering shaft 10 and the rack shaft 20 to each other. The rack and pinion mechanism 1 </ b> A converts the rotational motion of the pinion shaft 13 into linear motion of the rack shaft 20. The steered wheels 3 are connected to the rack shaft 20.

  The assist device 30 includes an electric motor 31 and a speed reduction mechanism 1 </ b> B that reduces the rotation of the electric motor 31 and transmits it to the column shaft 11. The speed reduction mechanism 1 </ b> B includes a worm shaft 32 that rotates by the output of the electric motor 31 and a worm wheel 33 that meshes with the worm shaft 32. The worm wheel 33 rotates integrally with the column shaft 11.

An operation of the vehicle steering device 1 when the steering wheel 2 rotates will be described.
As the steering wheel 2 rotates, the steering shaft 10 rotates. The rack shaft 20 moves in the axial direction X indicated by the arrow X in the drawing as the steering shaft 10 rotates. The axial direction X corresponds to the “axial direction of the rack shaft”. As the rack shaft 20 moves in the axial direction X, the direction of the steered wheels 3 changes. When the steering shaft 10 is rotating, the electric motor 31 rotates the worm wheel 33 based on the output of a torque sensor (not shown) that detects the torque applied to the steering shaft 10, and via the speed reduction mechanism 1B. Assist torque for assisting the movement of the rack shaft 20 is applied to the steering shaft 10. Thereby, the force required for operating the steering wheel 2 to move the rack shaft 20 is reduced. That is, the assist device 30 assists the operation of the steering wheel 2.

  As shown in FIG. 2, the rack guide mechanism 1 </ b> C includes a rack housing 40, a rack guide 51, a sheet member 52, a screw portion 53, a rotation member 54, a rotation regulating member 55, a pressing member 56, An elastic member 57 and a plug 58 are provided. The pressing member 56 and the elastic member 57 constitute a pressing force applying mechanism 1D.

  FIG. 2 shows a cross section of the rack housing 40 and the like that is perpendicular to the axial direction X (FIG. 1) of the rack shaft 20 and is along the axial direction Y of the pinion shaft 13. A linear direction in which the rack guide 51 moves in the rack housing 40 is referred to as “movement direction Z”. In the movement direction Z of the rack guide 51, the direction approaching the rack shaft 20 is referred to as “rack direction”, and the direction approaching the plug 58 is referred to as “plug direction”. The plug direction is a direction opposite to the rack direction and corresponds to a “counter rack direction” that is a direction away from the rack shaft 20. Therefore, the movement direction Z corresponds to the “movement direction defined by the rack direction and the anti-rack direction”.

  The rack housing 40 accommodates the rack shaft 20, the pinion shaft 13, the rack guide 51, and the like. The rack housing 40 includes a pinion shaft accommodating portion 41 and a rack guide accommodating portion 42. The pinion shaft accommodating portion 41 and the rack guide accommodating portion 42 are formed integrally with the rack housing 40. That is, the rack housing 40 serves as both a pinion housing and a rack guide housing. The rack housing 40 corresponds to a “housing for housing the rack shaft”.

The pinion shaft accommodating portion 41 accommodates the lower end portion of the pinion shaft 13. The pinion shaft housing portion 41 includes a seal member 43, a ball bearing 44, and a needle bearing 45.
The seal member 43 is located between the pinion shaft 13 and the rack housing 40 in the opening 41 </ b> A of the pinion shaft housing 41 that opens toward the outside of the rack housing 40. The seal member 43 suppresses entry of foreign matter into the rack housing 40.

  The ball bearing 44 and the needle bearing 45 are located at locations spaced apart from each other in the axial direction Y of the pinion shaft 13. The ball bearing 44 supports a portion of the pinion shaft 13 above the pinion 14. The needle bearing 45 supports a portion of the pinion shaft 13 below the pinion 14.

  The rack guide accommodating portion 42 accommodates the rack guide 51, the rotating member 54, the rotation restricting member 55, the pressing member 56, the elastic member 57, and the like. The rack guide accommodating portion 42 includes O-rings 46 and 47 and elastic members 48 and 49. The rack guide accommodating portion 42 is formed by a hole having a one-dot chain line C parallel to the moving direction Z as a central axis.

  The O-ring 46 is located between the rack guide housing portion 42 and the rack guide 51. The O-ring 46 reduces the collision between the rack guide housing portion 42 and the rack guide 51. The O-ring 47 is located between the rotation restricting member 55 and the pressing member 56. The O-ring 47 reduces the collision between the rotation restricting member 55 and the pressing member 56. The O-ring 47 corresponds to an “elastic member” positioned “between the pressing member and the regulating member”.

  The elastic member 48 is located between the rack guide 51 and the rotation member 54 in the movement direction Z of the rack guide 51. The elastic member 48 is configured by a square ring. The elastic member 48 has elasticity to separate the rack guide 51 and the rotation member 54 from each other in the movement direction Z. The elastic member 48 corresponds to an “elastic member” located “between the rack guide and the rotating member in the moving direction”.

  The elastic member 49 is located between the rotation restricting member 55 and the pressing member 56 in the movement direction Z of the rack guide 51. The elastic member 49 is configured by a square ring. The elastic member 49 has elasticity to separate the rotation restricting member 55 and the pressing member 56 from each other in the movement direction Z. The elastic member 49 corresponds to an “elastic member” positioned “between the pressing member and the regulating member”.

  The rack guide 51 is located between the rotating member 54 and the rack shaft 20 in the movement direction Z. The rack guide 51 is accommodated in the rack housing 40 so as to be movable in the movement direction Z. The rack guide 51 is pushed in the rack direction by the pressing member 56 via the rotating member 54. The rack guide 51 guides the movement of the rack shaft 20 in the axial direction X (FIG. 1) and presses the rack shaft 20 against the pinion shaft 13 via the seat member 52.

The sheet member 52 is formed of a resin having excellent wear resistance and a low friction coefficient. The seat member 52 is worn by the movement of the rack shaft 20 in the axial direction X (FIG. 1).
The threaded portion 53 is located at the end of the rack guide 51 in the plug direction. That is, the threaded portion 53 corresponds to “a threaded portion formed at the end of the rack guide on the side opposite to the rack direction”. Further, the screw portion 53 is formed integrally with the rack guide 51. That is, the screw portion 53 constitutes an end portion of the rack guide 51 in the plug direction, and the screw portion 53 itself corresponds to the “end portion of the rack guide on the non-rack direction side”.

  The rotating member 54 is positioned between the rotation restricting member 55 and the pressing member 56 and the rack guide 51 in the movement direction Z. The rotating member 54 is engaged with the screw portion 53. When viewed from the plug direction, the rotating member 54 rotates in the clockwise direction with respect to the rack guide 51 around the one-dot chain line C.

  The rotation restricting member 55 is located at a distance from the rack guide 51 in the plug direction, and is located between the plug 58 and the rotating member 54 in the movement direction Z. The rotation restricting member 55 is fixed to the rack guide accommodating portion 42. The rotation restricting member 55 restricts the rotation of the rotating member 54.

  The pressing member 56 is located at a distance from the rack guide 51 in the plug direction and is positioned between the elastic member 57 and the rotating member 54 in the movement direction Z. Further, the pressing member 56 is located in the rotation restricting member 55. The pressing member 56 is configured not to rotate around the alternate long and short dash line C, and is disposed so as to be movable in the movement direction Z. That is, the pressing member 56 does not rotate integrally with the rotating member 54. When the pressing member 56 comes into contact with the rotating member 54 and the sheet member 52 is worn, the rotating member 54 is pushed by the elasticity of the elastic member 57 to move the rotating member 54 and the rack guide 51 in the rack direction.

  The elastic member 57 is located between the plug 58 and the pressing member 56 in the movement direction Z. Further, the elastic member 57 is located in the rotation restricting member 55. The elastic member 57 is configured by a coil spring. The elastic member 57 has elasticity for separating the plug 58 and the pressing member 56 from each other in the movement direction Z. In other words, the elastic member 57 applies a force acting in the rack direction to the pressing member 56. The pressing force applying mechanism 1 </ b> D including the pressing member 56 and the elastic member 57 applies force in the rack direction and the rotation direction R (FIG. 4B) to the rotating member 54.

  The plug 58 is screwed into the inner periphery of the rack guide housing portion 42 at an opening 42A of the rack guide housing portion 42 that opens toward the outside of the rack housing 40. That is, the plug 58 is fixed to the rack guide accommodating portion 42.

  As shown in FIG. 3, the rack guide 51 includes a guide groove 51A in which the seat member 52 and the rack shaft 20 (FIG. 2) are fitted, and a ring groove 51B in which the O-ring 46 (FIG. 2) is fitted. FIG. 3 is a perspective view of the rack guide mechanism 1C of FIG. 2 in an exploded state. FIG. 3 shows only the rack guide 51, the screw portion 53, the rotation member 54, the rotation restriction member 55, and the pressing member 56.

  The screw portion 53 has a male screw 53A to which the rotating member 54 is fitted. The male screw 53A is a left-hand screw. The rotating member 54 and the rotation restricting member 55 have shapes that are hooked to each other. The pressing member 56 has a shape that rotates the rotating member 54 around the alternate long and short dash line C with respect to the rack guide 51.

  As shown in FIG. 4, the rotating member 54 includes a female screw 54A and an inclined protrusion 54B. FIG. 4B shows a state in which the rotating member 54 of FIG. 4A is viewed from the plug direction. The rotation member 54 rotates in the rotation direction R, which is a clockwise direction when viewed from the plug direction, with the central axis C1 as the center of rotation. The rotating member 54 moves in the plug direction with respect to the rack guide 51 when rotating in the rotation direction R with respect to the rack guide 51 (FIG. 3). The inclined protrusion 54B corresponds to “a rotation-side regulating portion formed at an end of the rotating member on the side opposite to the rack”. The rotation direction R corresponds to “one direction of rotation”.

  The female screw 54 </ b> A constitutes the inner periphery of the rotating member 54. That is, the female screw 54 </ b> A is formed integrally with the rotating member 54. The female screw 54A is a left-hand screw. The female screw 54A is fitted to the male screw 53A.

  The inclined protrusion 54B is located at the end of the rotating member 54 in the plug direction. The inclined protrusion 54B is formed integrally with the rotating member 54. That is, the inclined protrusion 54 </ b> B constitutes an end portion of the rotating member 54 in the plug direction. The inclined protrusion 54B protrudes toward the plug direction in the movement direction Z of the rack guide 51 (FIG. 2). The inclined protrusion 54B has an inclined surface 54C that is inclined with respect to the central axis C1, and a vertical surface 54D that is perpendicular to the rotation direction R. The degree to which the inclined protrusion 54B protrudes in the plug direction increases as the rotation member 54 moves in the rotation direction R. The four inclined protrusions 54B are located at equal intervals in the circumferential direction of the rotating member 54. The inclined surface 54 </ b> C corresponds to “a rotating side inclined surface that is inclined from the rack direction side toward the non-rack direction side as it goes toward the one rotation direction side”. Further, the vertical surface 54D corresponds to “a rotation-side regulating surface continuous with the rotation-side inclined surface”.

As shown in FIG. 5, the rotation restricting member 55 includes an elastic member accommodating portion 55A, a pressing member accommodating portion 55B, and a rotation restricting protrusion 55C. FIG. 5B shows a state where the rotation restricting member 55 in FIG. 5A is viewed from the rack direction.

Pressing member accommodating portion 55 B constitutes the inner circumference of the rotation regulating member 55 which opens in the rack direction. Pressing member accommodating portion 55 B accommodates a pressing member 56 (FIG. 2). The elastic member accommodating portion 55 A constitutes the inner circumference of the rotation regulating member 55 which is open to the plug direction. Elastic member accommodating portion 55 A has a smaller inner diameter than the pressing member accommodating portion 55 B. Elastic member accommodating portion 55 A accommodates the plug-side end and the elastic member 57 of the pressing member 56 (FIG. 2). It is continuous with each other and the pressing member accommodating portion 55 B and the elastic member accommodating portion 55 A.

  The rotation restricting protrusion 55C is located at the end of the rotation restricting member 55 in the rack direction. The rotation restricting protrusion 55 </ b> C is formed integrally with the rotation restricting member 55. That is, the rotation restricting protrusion 55 </ b> C constitutes an end of the rotation restricting member 55 in the rack direction. The rotation restricting protrusion 55C protrudes in the rack direction in the movement direction Z of the rack guide 51 (FIG. 2). The rotation restricting projection 55C has an inclined surface 55D that is inclined with respect to the moving direction Z, and a vertical surface 55E that is perpendicular to the rotating direction R (FIG. 4) of the rotating member 54. The inclined surface 55D guides the rotation of the rotating member 54 that rotates in the anti-rack direction. The vertical surface 55E is caught by the vertical surface 54D (FIG. 4) of the inclined protrusion 54B. The rotation restricting member 55 restricts the rotation of the rotating member 54 in the rotation direction R by hooking the vertical surface 55E of the rotation restricting protrusion 55C and the vertical surface 54D of the rotating member 54 together. The eight rotation restricting protrusions 55C are located at equal intervals so as to form an annular shape with the center point C2 as the center when viewed from the rack direction. The center point C2 is located on the center axis C1 of the rotating member 54. The rotation restricting protrusion 55C is “located on the side opposite to the rack with respect to the rotating member and fixed to the housing. When the distance between the rotating member and the rotating member in the moving direction is less than a predetermined amount, It corresponds to a “restricted portion that restricts rotation and allows the rotation of the rotating member relative to the rack guide when the distance from the rotating member in the moving direction is a predetermined amount or more”. The inclined surface 55D corresponds to “a fixed-side inclined surface having a shape corresponding to the rotating-side inclined surface”. The vertical surface 55E corresponds to “a fixed-side regulating surface having a shape corresponding to the rotation-side regulating surface”.

  As shown in FIG. 6, the pressing member 56 includes a pressing protrusion 56A and a ring groove 56B into which the O-ring 47 (FIG. 2) is fitted. FIG. 6B shows a state where the pressing member 56 of FIG. 6A is viewed from the rack direction.

  The pressing protrusion 56 </ b> A is located at the end of the pressing member 56 in the rack direction. The pressing protrusion 56 </ b> A is formed integrally with the pressing member 56. That is, the pressing protrusion 56 </ b> A constitutes an end portion of the pressing member 56 in the rack direction. The pressing protrusion 56A protrudes in the rack direction in the movement direction Z of the rack guide 51 (FIG. 2). The pressing member 56 presses the inclined protrusion 54B (FIG. 4) of the rotating member 54 in the rack direction by the pressing protrusion 56A. The pressing member 56 rotates the rotating member 54 in the rotation direction R (see FIG. 4) by pressing the inclined protrusion 54B. The eight pressing protrusions 56A are positioned at equal intervals so as to form an annular shape with the center point C3 as the center when viewed from the rack direction. The center point C3 is located on the center axis C1 of the rotating member 54.

The operation of the rack guide mechanism 1C will be described with reference to FIG.
As shown in FIG. 7A, the rotation restricting member 55 restricts the rotation of the rotating member 54 when the degree of wear of the sheet member 52 (FIG. 2) is small. As shown in FIG. 7B, when the sheet member 52 is worn, the pressing member 56 pushes the inclined protrusion 54B of the rotating member 54, thereby causing the rotating member 54 and the rack guide 51 (FIG. 2) to move in the rack direction. Move to. As shown in FIG. 7C, when the degree of wear of the sheet member 52 becomes a predetermined level or more, the inclined protrusion 54B of the rotation member 54 can get over the rotation restriction protrusion 55C of the rotation restriction member 55. Become. That is, the restriction on the rotation of the rotation member 54 by the rotation restriction member 55 is released. For this reason, as shown in FIG. 7D, the pressing member 56 presses the inclined surface 54C of the inclined protrusion 54B, whereby the rotating member 54 rotates in the rotation direction R. At this time, the rotary motion of the rotary member 54 is converted into a linear motion in the movement direction Z by the male screw 53A of the screw portion 53 and the female screw 54A of the rotary member 54. As a result, the rotation member 54 moves in the plug direction in the movement direction Z. Then, as shown in FIG. 7E, the rotation restricting member 55 restricts the rotation of the rotating member 54 again.

  FIG. 8 shows the entire rack guide mechanism 1C corresponding to the state shown in FIG. FIG. 9 shows the entire rack guide mechanism 1C corresponding to the state shown in FIG. The degree of wear of the sheet member 52 in FIG. 9 is larger than the degree of wear of the sheet member 52 in FIG. When the sheet member 52 is worn by a predetermined amount or more, the rotation restriction of the rotation member 54 by the rotation restriction member 55 is released, the rotation member 54 rotates, and the rotation member 54 moves in the plug direction. As a result, the dimensions from the rack guide 51 to the rotating member 54 change. That is, the dimension D2 from the rack guide 51 to the rotating member 54 when the degree of wear of the sheet member 52 is larger than the dimension D1 from the rack guide 51 to the rotating member 54 when the degree of wear of the sheet member 52 is small. Becomes larger. Thus, the rack guide mechanism 1 </ b> C compensates for the gap generated by the wear of the sheet member 52, and suppresses a reduction in the force pushing the rack guide 51 in the rack direction. That is, the reduction of the force pressing the rack shaft 20 against the pinion shaft 13 is suppressed.

The vehicle steering device 1 and the rack guide mechanism 1C of the present embodiment have the following effects.
(1) The rack guide mechanism 1C of the vehicle steering apparatus 1 includes a rack shaft 20, a rack housing 40, a rack guide 51, a threaded portion 53, a rotating member 54, a pressing force applying mechanism 1D, and a rotation restricting protrusion. 55C. When the pressing force applying mechanism 1D applies a force in the rack direction to the rotating member 54, the rotating member 54 and the rack guide 51 move in the rack direction. When the interval between the rotation restricting protrusion 55C and the rotating member 54 in the movement direction of the rack guide 51 is changed from less than a predetermined amount to a predetermined amount or more, the restriction on the rotation of the rotating member 54 by the rotation restricting protrusion 55C is released. The pressing force applying mechanism 1 </ b> D applies a force in the rotation direction R to the rotating member 54, whereby the rotating member 54 rotates and the rotating member 54 meshed with the threaded portion 53 becomes the rack guide 51. Move in the plug direction. When the rotating member 54 moves in the plug direction, the movement of the pressing member 56 in the rack direction is suppressed, and the elastic member 57 is suppressed from becoming longer in the moving direction. For this reason, compared with the structure in which the elastic member 57 is lengthened by the amount of movement of the rack guide 51 in the rack direction, a reduction in the force applied from the elastic member 57 to the pressing member 56 is suppressed, and the rack guide 51 is moved to the rack shaft. It can suppress that the force pressed against 20 falls.

  (2) When the rotation of the rotation member 54 is not restricted by the rotation restriction protrusion 55C, the rotation member 54 tries to rotate by the force in the rotation direction R applied by the pressing force applying mechanism 1D. When the element vibrates, the rack guide 51 temporarily moves in the rack direction. For this reason, there is a possibility that the force with which the rack guide 51 presses the rack shaft 20 becomes excessive in a state where the vibration is suppressed. According to the present invention, in a state where the rotation restricting protrusion 55 </ b> C restricts the rotation of the rotating member 54, the rotating member 54 does not rotate, and therefore the rotating member 54 does not move in the plug direction with respect to the rack guide 51. For this reason, it is possible to suppress the rack guide 51 from being excessively pressed against the rack shaft 20.

  (3) A plurality of rotation restricting protrusions 55C are formed in the circumferential direction along the direction in which the rotating member 54 rotates. For this reason, the rotation of the rotation member 54 can be regulated a plurality of times before the rotation member 54 makes one rotation.

  (4) A plurality of inclined protrusions 54B are formed in the circumferential direction along the direction in which the rotating member 54 rotates. For this reason, the rotation of the rotating member 54 can be reliably restricted by bringing the vertical surface 54D of each of the plurality of inclined protrusions 54B into contact with the vertical surface 55E of each of the plurality of rotation restricting protrusions 55C.

  (5) The rack guide mechanism 1 </ b> C of the vehicle steering apparatus 1 includes an elastic member 48 between the rack guide 51 and the rotation member 54 in the movement direction Z. For this reason, it is possible to apply a force that moves the rotating member 54 in the plug direction with respect to the rack guide 51 using the elastic member 48. Therefore, the movement of the rotation member 54 in the plug direction with respect to the rack guide 51 can be assisted.

  (6) The vehicle steering apparatus 1 includes a rotation restricting member 55 on which a rotation restricting protrusion 55 </ b> C is formed, and further includes an O-ring 47 and an elastic member 49 between the pressing member 56 and the rotation restricting member 55. For this reason, the collision between the pressing member 56 and the rotation restricting member 55 can be reduced.

  The present invention includes embodiments other than the above-described embodiment. Hereinafter, the modification of the said embodiment as other embodiment of this invention is shown. The following modifications can be combined with each other.

  In the vehicle steering apparatus 1 of the embodiment, the screw portion 53 and the rotating member 54 are fitted together by the female screw 54A of the rotating member 54 and the male screw 53A of the screw portion 53. On the other hand, in the vehicle steering apparatus 1 of the modified example, the rotating member 54 has a male screw (not shown), a screw portion has a female screw (not shown), and the screw portion 53 and the rotating member 54 are the rotating member 54. The male screw and the female screw of the screw part 53 are fitted together.

  In the embodiment, the screw portion 53 is formed integrally with the rack guide 51. On the other hand, the threaded portion 53 of the modification is formed separately from the rack guide 51 and is fixed to the end of the rack guide 51 in the non-rack direction. That is, the screw portion and the rack guide may not be formed integrally.

  The rotation restricting protrusion 55 </ b> C of the embodiment is formed on the rotation restricting member 55. On the other hand, a rotation restricting protrusion (not shown) of the modified example is formed on the plug 58. That is, the member in which the restriction portion is formed can be changed.

  The vehicle steering device 1 of the embodiment is configured as a column assist type electric power steering device. On the other hand, the vehicle steering apparatus according to the modification is configured as a pinion assist type or rack assist type electric power steering apparatus.

DESCRIPTION OF SYMBOLS 1 ... Vehicle steering device, 1A ... Rack and pinion mechanism, 1B ... Deceleration mechanism, 1C ... Rack guide mechanism, 1D ... Pushing force application mechanism, 2 ... Steering wheel, 10 ... Steering shaft, 11 ... Column shaft, 12 ... Intermediate Ito shaft, 13 ... Pinion shaft, 14 ... Pinion, 20 ... Rack shaft, 21 ... Rack, 30 ... Assist device, 31 ... Electric motor, 32 ... Worm shaft, 33 ... Worm wheel, 40 ... Rack housing (housing), 41 ... Pinion shaft housing part, 41A ... Opening part, 42 ... Rack guide housing part, 42A ... Opening part, 43 ... Sealing member, 44 ... Ball bearing, 45 ... Needle bearing, 46, 47 ... O-ring, 48, 49 ... Elasticity 51, rack guide, 51A, guide groove, 51B, ring groove, 52 Sheet member 53 ... Screw part (screw part), 53A ... Male screw, 54 ... Rotating member, 54A ... Female thread, 54B ... Inclined protrusion (rotation side regulating part), 54C ... Inclined surface (rotating side inclined surface), 54D ... vertical surface (rotation side regulating surface), 55 ... rotation regulating member (regulating member), 55A ... elastic member accommodating portion, 55B ... pressing member accommodating portion, 55C ... rotation regulating projection (regulating portion), 55D ... inclined surface (fixed) Side inclined surface), 55E ... vertical surface (fixed side regulating surface), 56 ... pressing member, 56A ... pressing protrusion, 56B ... ring groove, 57 ... elastic member, 58 ... plug.

Claims (6)

A rack shaft that moves in an axial direction;
A housing that houses the rack shaft;
Guides the movement of the rack shaft and is housed in the housing in a movable state defined by a rack direction that is a direction approaching the rack shaft and an anti-rack direction that is a direction away from the rack shaft. Rack guide to be
A threaded portion formed at an end of the rack guide on the side opposite to the rack;
A rotating member that meshes with the screw portion and moves in the anti-rack direction with respect to the rack guide when rotating in one direction of rotation with respect to the rack guide;
And in the rotation direction of force by cooperation with the previous SL rack force and the rotating member which imparts to the rotating member, and a pressing member in contact with the rotary member, acting on the rack direction A pressing force applying mechanism having a first elastic member that applies force to the pressing member;
A second elastic member provided between the rack guide and the rotating member in the moving direction;
The rotating member is located on the side opposite to the rack direction with respect to the rotating member and is fixed to the housing, and the rotating member with respect to the rack guide when the distance from the rotating member in the moving direction is less than a predetermined amount. A vehicle steering apparatus comprising: a restricting portion that restricts rotation of the rotating member relative to the rack guide when an interval between the rotating member and the rotating member in the moving direction is equal to or greater than the predetermined amount. Before SL rotating member has a rotation-side restricting portion which is formed at an end portion of the counter-rack direction side in the rotating member,
The rotation-side regulating portion includes a rotation-side inclined surface that is inclined from the rack direction side toward the counter-rack direction side toward the rotation one direction side, and a rotation-side restriction surface that is continuous with the rotation-side inclination surface. Have
The restricting portion has a fixed-side inclined surface having a shape corresponding to the rotating-side inclined surface, and a fixed-side restricting surface having a shape corresponding to the rotating-side restricting surface,
The fixed-side regulating surface contacts the rotating-side regulating surface when the distance between the fixed-side inclined surface and the rotating-side inclined surface in the moving direction is less than the predetermined amount, and the fixed-side inclined surface in the moving direction When the distance between the surface and the rotation-side inclined surface is equal to or greater than the predetermined amount, it does not contact the rotation-side restriction surface
The vehicle steering apparatus according to claim 1. Before SL regulating portion is formed in plurality in the circumferential direction along the direction in which the rotary member is rotated
The vehicle steering apparatus according to claim 1 or 2. Before Symbol rotation-side regulating portion is formed in plurality in the circumferential direction along the direction in which the rotary member is rotated
The vehicle steering apparatus according to claim 3, which quotes claim 2. Before Symbol steering apparatus for a vehicle includes a regulating member for the regulating portion is formed, further has an elastic member between the restricting member and the pressing member
The vehicle steering apparatus according to any one of claims 1 to 4. A rack guide mechanism for guiding the axial movement of a rack shaft accommodated in a housing,
Guides the movement of the rack shaft and is housed in the housing in a movable state defined by a rack direction that is a direction approaching the rack shaft and an anti-rack direction that is a direction away from the rack shaft. Rack guide to be
A threaded portion formed at an end of the rack guide on the side opposite to the rack;
A rotating member that meshes with the screw portion and moves in the anti-rack direction with respect to the rack guide when rotating in one direction of rotation with respect to the rack guide;
And in the rotation direction of force by cooperation with the previous SL rack force and the rotating member which imparts to the rotating member, and a pressing member in contact with the rotary member, acting on the rack direction A pressing force applying mechanism having a first elastic member that applies force to the pressing member;
A second elastic member provided between the rack guide and the rotating member in the moving direction;
The rotating member is located on the side opposite to the rack direction with respect to the rotating member and is fixed to the housing, and the rotating member with respect to the rack guide when the distance from the rotating member in the moving direction is less than a predetermined amount. And a restricting portion that restricts rotation of the rotating member relative to the rack guide when the distance between the rotating member and the rotating member in the moving direction is equal to or greater than the predetermined amount.