JP4876739B2 - Vehicle steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle steering system high in practicability. <P>SOLUTION: The steering system is furnished with: a steering rod 92 to steer left and right wheels by moving in the axial direction; a steering operation member to be operated by a driver; a steering shaft (shaft) 20 rotated by rotation of the steering operation member; and a motion change-over mechanism 100 to change rotation of the shaft to moving motion in the axial direction of the steering rod. A rotating area of the shaft is limited by a rotation restraint mechanism 120, and a steering area of the wheels is also limited by furnishing the shaft rotation restraint mechanism 120 to restrain rotation of the shaft. That is, a load to the motion change-over mechanism is reduced when the steering area is limited. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a vehicle steering apparatus for steering wheels.

In a general vehicle steering apparatus, a steering shaft is rotated by a driver's operation of a steering operation member such as a steering wheel (hereinafter sometimes simply referred to as an “operation member”), and the rotation of the steering shaft is the axis of a steered rod. The wheel is steered by the movement of the steered rod. Further, in general, the limitation of the steering range (also referred to as “steering range”) in which the wheels can be steered is described in Patent Document 1 below. The steering device is subjected to a load due to an operating force applied to the operating member, an inertial force of the operating member, and the like. In particular, in the case of a steering device including a steering assist device as described in Patent Document 2 below, the load is relatively large.
JP 2005-88777 A JP 2005-67295 A

  The mechanism for converting the rotation of the steering shaft into the movement operation of the steered rod is provided in the engaging portion, and is, for example, a rack and pinion mechanism. The load when the steered range is limited is particularly large in the motion conversion mechanism because of its structure, and it is desired to reduce the load in the motion conversion mechanism. By reducing the load, the practicality of the steering device is reduced. It is thought to improve. This invention is made | formed in view of such a situation, and makes it a subject to provide the steering device for vehicles with high practicality.

In order to solve the above problems, a vehicle steering apparatus according to the present invention includes a steering rod that moves in the axial direction to steer left and right wheels, a steering operation member that is operated by a driver, and the steering operation member. A steering shaft that rotates due to rotation of the steering shaft, a motion conversion mechanism that converts the rotation of the steering shaft into an axial movement of the steered rod, and a power source. A steering assist device that assists in the steering of the wheel, a portion of the steering shaft to which a rotational force is applied by the steering assist device, and the motion conversion mechanism, between, further comprising a rotation inhibiting mechanism for inhibiting the rotation of the steering shaft And butterflies.

  In the vehicle steering device of the present invention, for example, the rotation range of the steering shaft can be limited by the rotation suppression mechanism, and the turning range can be limited. When the range is limited to limit the steered range, the rotation suppression mechanism can be configured to suppress the rotation of the steering shaft prior to the limitation. Therefore, according to the vehicle steering device of the present invention, it is possible to reduce the load on the motion conversion mechanism when the turning range is limited.

Aspects of the Invention

  In the following, some aspects of the invention that can be claimed in the present application (hereinafter sometimes referred to as “claimable invention”) will be exemplified and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is merely for the purpose of facilitating the understanding of the claimable inventions, and is not intended to limit the combinations of the constituent elements constituting those inventions to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention.

Note that in the following sections, generally, (1) section and (3) terms and (4) a combination of the term corresponds to claim 1, in claim 2 (2) section (7) The combination of items (9) to (9) is in claim 3 , the combination of items (11) and (12) is in claim 4 , (13) is in claim 5 , and (14). Corresponds to claim 6 , (16) corresponds to claim 7 , and (18) corresponds to claim 8 .

(1) A steering rod that connects the left and right wheels and steers the left and right wheels by movement in the axial direction;
A steering operation member that is rotated by a driver;
A steering shaft that is attached to one end of the steering operation member, engages with the steered rod at the other end, and rotates by rotation of the steering operation member;
An operation conversion mechanism provided at a position where the steering shaft and the steered rod engage with each other, and converting the rotation of the steering shaft into an axial movement of the steered rod;
A vehicle steering apparatus comprising: a shaft rotation suppression mechanism that suppresses rotation of the steering shaft.

  When a mechanism that simply restricts the operation of the steered rod is provided to limit the steered range, the motion conversion mechanism is compared with the operation force applied to the steering operation member, the inertial force of the operation member, etc. A large load acts, and in some cases, a shocking load acts. In the aspect of this section, the above-mentioned shaft rotation suppression mechanism (hereinafter sometimes simply referred to as “rotation suppression mechanism”) that suppresses the rotation of the steering shaft is provided, and the turning range is limited by the function of the mechanism. It is possible to reduce the load on the motion conversion mechanism at the time.

  The rotation suppression mechanism can be, for example, a mechanism that limits the rotation range of the steering shaft, that is, a mechanism that prohibits rotation beyond a certain range of the steering shaft. When such a rotation suppression mechanism is provided, it is possible to limit the steered range by the mechanism itself without using a mechanism that restricts the operation of the steered rod. If such a rotation suppression mechanism is provided, when the steering range is limited, the mechanism receives the rotational force of the steering shaft, and the burden on the motion conversion mechanism at that time is greatly reduced. Will be.

  The rotation suppression mechanism can be, for example, a mechanism that suppresses the rotation of the steering shaft, that is, a mechanism that provides resistance to the rotation of the steering shaft. In the case of limiting the steered range by providing a mechanism that restricts the range of movement of the steered rod, prior to the limit, that is, before the steered range, the rotation suppression mechanism reduces the rotational force of the steering shaft. If reduced, the burden on the motion conversion mechanism when the steered range is restricted is reduced. For example, an elastic force, a friction force, or the like can be used as a force for suppressing the rotation of the steering shaft.

  Note that the “steering shaft” described in this section is not particularly limited in its structure. For example, as described later, a plurality of shaft members are connected to each other. Also good. When such a steering shaft is employed, the rotation inhibition mechanism may inhibit any rotation of the plurality of shaft members. In addition, the structure of the “motion converting mechanism” described in this section is not particularly limited, and the mode of this section is applicable to various mechanisms such as a rack and pinion mechanism and a ball screw mechanism. Is possible. Furthermore, the aspect of this section is related to the limitation of the steering range, in the case where the steering range is limited at one of the steering limit when turning left and the turning limit when turning right, or The present invention can also be applied to the case where the rotation is restricted in both of them, and the rotation suppression mechanism only needs to restrict at least one of the right rotation and the left rotation of the steering shaft.

  (2) The operation conversion mechanism includes a rack provided on the steered rod and a pinion provided at the other end of the steering shaft and meshing with the rack. Vehicle steering system.

  The mode of this section is a mode in which a rack and pinion mechanism is adopted as the motion conversion mechanism. According to the aspect of this section, since the load on the rack and pinion mechanism when the steering range is limited is relatively small, the strength of the meshing portion between the rack and the pinion can be relatively small.

  A general rack and pinion mechanism is provided with a mechanism that urges the rack toward the pinion so that the rack and the pinion are reliably engaged with each other. For example, when a large load is applied to the meshing portion between the rack and the pinion, it is necessary to increase the urging force by this mechanism, which causes problems such as an increase in the size of the mechanism. From this point of view, the aspect of this section is suitable for a steering device that employs a rack and pinion mechanism because it can enjoy advantages such as downsizing the mechanism.

(3) The vehicle steering device is
(1) or (2) comprising a steering assist device that has a power source and assists the steering of the wheel by applying a rotational force to the steering shaft at an intermediate portion of the steering shaft. Vehicle steering system.

  The steering device described in this section is a so-called power steering device. The “steering assist device” described in this section is a structure that applies a rotational force (hereinafter sometimes referred to as “assist force”) as a force for assisting wheel steering to the steering shaft. Is not particularly limited. For example, an electric motor may be used as a power source, or a hydraulic actuator may be used as a power source. The “intermediate portion of the steering shaft” referred to in this section broadly means between the portion of the steering shaft where the operating member is attached and the portion where the steering rod of the steering shaft is engaged.

  (4) The shaft rotation suppression mechanism is configured to suppress rotation of the steering shaft at a portion of the steering shaft closer to the steered rod than a portion to which rotational force is applied by the steering assist device of the steering shaft. The vehicle steering device according to the item (3).

  According to the aspect of this section, when the steering range of the wheel is limited, it is possible to reduce the load caused by the assist force by the steering assist device. In particular, as will be described in detail later, a mechanism for limiting the moving range of the steered rod is provided to limit the steered range, which is suitable for a steering apparatus configured to suppress the rotation of the steering shaft prior to the limit. .

(5) The steering shaft includes a torsion portion that is a portion that is substantially twisted by the rotation of the steering operation member,
The vehicle steering device according to (3) or (4), wherein the steering assist device applies a rotational force having a magnitude corresponding to a torsion amount of the torsion portion.

  In the aspect of this section, if the rotation of the steering shaft is suppressed in the portion closer to the operation member than the torsion portion of the steering shaft, for example, the twist of the torsion portion after the suppression can be reduced, and the turning range is limited. Or it becomes possible to reduce the load to the motion conversion apparatus resulting from the assist force by the steering assist apparatus after a restriction | limiting. On the other hand, if the rotation of the steering shaft is suppressed in the portion closer to the steered rod than the torsion portion, the assist force when the turning range is restricted or after the restriction is relatively large due to torsion of the torsion portion after the inhibition. Become. In view of this, when the rotation of the steering shaft is suppressed in the portion closer to the steered rod than the torsion portion, the rotation is suppressed in the portion closer to the steered rod than the portion to which the rotational force of the steering shaft is applied. It is desirable to do. This is particularly desirable in a steering apparatus that is configured to limit the steered range by providing a mechanism for restricting the range of movement of the steered rod and to suppress the rotation of the steering shaft prior to the limit.

  (6) The steering shaft includes an operation member side shaft member including the one end portion, a steered rod side shaft member including the other end portion, and between the operation member side shaft member and the steered rod side shaft member. An intermediate shaft member positioned at a position, a first universal joint for connecting the operation member side shaft member and the intermediate shaft member, and a second universal joint for connecting the steered rod side shaft member and the intermediate shaft member. The vehicle steering device according to any one of (1) to (5), comprising:

  The mode of this section is a mode in which the structure of the steering shaft is specifically limited. The “shaft member” described in this section may be configured to be extendable and contractable, for example, in order to ensure a telescopic function, a tilt function, an impact absorption function, and the like. In the aspect of this section, when a steering assist device having a structure for applying a rotational force to the operation member side shaft member is provided, if the rotation of the operation member side shaft is suppressed, When limiting, the load on the portion including the intermediate shaft member, the steered rod side shaft member, and the two universal joints can be reduced, so that the strength of the portion can be relatively reduced.

  (7) The vehicle steering device includes a tube member that is supported by the vehicle body and rotatably holds the portion of the steering shaft that is close to the steering operation member and is inserted into the steering shaft. The vehicle steering device according to any one of (1) to (6), further including a steering column including a portion of the steering shaft close to a steering operation member.

(8) The vehicle steering device is
A steering assist device for assisting the steering of the wheels by providing a power source and applying a rotational force to the steering shaft at an intermediate portion of the steering shaft;
The vehicle steering device according to (7), wherein the steering assist device is provided in the steering column and applies a rotational force to a portion of the steering shaft near the steering operation member.

  The modes described in the above two items are modes having a so-called steering column, and “the portion near the steering operation member of the steering shaft” includes, for example, the steering shaft, the operation member side shaft member, the intermediate shaft member, the rolling shaft. In the case of including a rudder rod side shaft member and two universal joints, for example, an operation member side shaft member corresponds. The latter aspect is simply an aspect in which a steering assist device is incorporated in the steering column.

  (9) Item (7) or (8), wherein the shaft rotation inhibiting mechanism is provided in the steering column and inhibits rotation of the steering shaft at a portion near the steering operation member of the steering shaft. The vehicle steering device according to claim 1.

  The mode of this section is a mode in which a rotation suppression mechanism is incorporated in the steering column. According to the aspect of this section, a compact steering device is realized. In addition, if a steering assist device is installed in the steering column together with the rotation suppression mechanism, a more compact steering device is realized, and the rotation of the steering shaft is suppressed in the vicinity of the steering rod side where the assist force is applied. This aspect is easily realized.

(10) The vehicle steering device is
A housing that is fixed to a vehicle body, holds the steered rod so as to be movable in the axial direction thereof, and rotatably holds the other end portion of the steering shaft, and includes a housing that includes the motion conversion mechanism ( The vehicle steering device according to 9).

(11) The vehicle steering device is
A housing that is fixed to a vehicle body, holds the steered rod so as to be movable in the axial direction thereof, and rotatably holds the other end portion of the steering shaft, and includes a housing that includes the motion conversion mechanism ( The vehicle steering device according to any one of items 1) to (8).

  (12) The vehicle steering apparatus according to (11), wherein the shaft rotation suppression mechanism is provided in the housing and suppresses rotation of the steering shaft at the other end.

  The modes of the above three terms are modes in which the motion conversion mechanism is disposed in a housing held by the vehicle body. In the aspect of the last term among the three, since the rotation restraining mechanism is disposed in the housing, the steering device can be made compact. In addition, the dust prevention, waterproofness, and the like for the rotation suppression mechanism are also improved.

  (13) The steering for a vehicle according to any one of (1) to (12), wherein the shaft rotation suppression mechanism limits a turning range of a wheel by limiting a rotation range of the steering shaft. apparatus.

  The aspect of this item is an aspect which restrict | limits the steering range of the wheel which restrict | limits steering shaft rotation as demonstrated previously. According to the aspect of this section, as described above, since the turning range is limited by the rotation suppression mechanism itself, it is possible to significantly reduce the load on the motion conversion mechanism.

  (14) The shaft rotation suppression mechanism engages with the steering shaft and moves in conjunction with the rotation of the steering shaft, and a movement that abuts the moving body to limit the movement of the moving body. The vehicle steering device according to item (13), including a restricting body.

  The aspect described in this section is an aspect in which the structure of the rotation suppression mechanism is specifically limited, and is a structure that limits the steered range by restricting the operation of the moving body that interlocks with the rotation of the steering shaft. Yes. A general steering device has a structure in which the steering shaft rotates a plurality of times within the entire steering range (a rotation when one rotation is 360 °), and thus directly restricts the rotation of the steering shaft. Compared to the case, the steered range can be easily limited.

(15) The shaft rotation suppression mechanism is
A male screw provided on the outer periphery of the steering shaft;
As the moving body that has a female screw that is screwed with the male screw and is not rotatable relative to the steering shaft and is movable in the axial direction, the moving body moves in the axial direction as the steering shaft rotates. The vehicle steering device according to item (14), including a nut member.

  The mode of this section is a mode in which a screw mechanism is adopted as the structure of the rotation suppression mechanism, specifically, a mechanism for linking the rotation of the steering shaft and the moving operation of the moving body. According to the aspect of this section, a rotation suppression mechanism having a relatively simple structure is realized. Note that the ratio of the moving amount of the moving body to the rotating amount of the steering shaft can be arbitrarily set by adjusting the lead angle of the screw.

(16) The vehicle steering apparatus includes a rod operation restriction mechanism that restricts a steered range of a wheel by restricting an operation range of the steered rod,
The shaft rotation suppression mechanism is configured to suppress the rotation of the steering shaft prior to the limitation of the wheel turning range by the rod operation limiting mechanism, according to any one of (1) to (12). Vehicle steering system.

  As described above, the aspect of this section is provided with a mechanism for limiting the moving range of the steered rod in order to limit the steered range, and before the steered range limited thereby, This is a mode in which a mechanism for suppressing rotation, in other words, a mechanism for giving resistance to rotation of the steering shaft is provided. According to the aspect of this section, as described above, after the rotational force of the steering shaft is reduced by the rotation suppression mechanism, the movement operation of the steered rod is limited. It becomes possible to reduce the load. In particular, in the steering device according to the aspect of this aspect, as described above, if the rotation of the steering shaft is suppressed in the portion closer to the steered rod than the portion where the assist force of the steering shaft is applied, the rod operation restriction is performed. When the turning range is limited by the mechanism, it is possible to effectively reduce the load caused by the assist force. For this reason, in the aspect of this section, it is desirable to suppress the rotation of the steering shaft at the above portion.

  In the aspect in which the rotation suppression mechanism described above limits the rotation range of the steering shaft, when the external input from the wheel acts due to road surface unevenness or the like, the rotation suppression mechanism may limit the turning range. In this case, a relatively large load due to external input may be applied to the motion conversion mechanism. In the aspect of this section, even when such an external input is applied, the rotation of the steering shaft is suppressed by the rotation suppression mechanism prior to the limitation of the steering range by the steering rod operation limiting mechanism. It is possible to reduce the load on the motion conversion mechanism due to the above. Moreover, since the steered range is restricted by the steered rod operation restricting mechanism even with respect to the external input after the steered range is restricted, the load on the motion converting mechanism is small.

  (17) The vehicle steering device according to (16), wherein the shaft rotation suppression mechanism suppresses rotation of the steering shaft using an elastic force.

  The mode of this section is a mode configured to suppress the rotation of the steering shaft using an elastic body such as a spring or rubber, for example, and a rotation suppression mechanism with a simple structure is realized.

(18) When the shaft rotation inhibiting mechanism engages with the steering shaft and moves in conjunction with the rotation of the steering shaft, and the movement of the moving body in a state in which the moving body is in contact An elastic body that elastically deforms and applies an elastic force to the moving body,
The vehicle steering device according to (16) or (17), wherein the rod operation restriction mechanism restricts an operation range of the steered rod in a state where an elastic force is applied to the moving body. .

(19) The shaft rotation suppression mechanism is
A male screw provided on the outer periphery of the steering shaft;
As the moving body that has a female screw that is screwed with the male screw and is not rotatable relative to the steering shaft and is movable in the axial direction, the moving body moves in the axial direction as the steering shaft rotates. The vehicle steering apparatus according to item (18), including a nut member.

  The modes of the above two terms are modes in which a specific structure of the rotation suppression mechanism using elastic force is limited. The aspects of these terms are similar to the two aspects described above, that is, the aspects related to the specific structure of the rotation suppression mechanism that restricts the rotation range of the steering shaft. According to the two terms, it is possible to enjoy the same advantages as those described above.

  Hereinafter, some embodiments and modifications of the claimable invention will be described in detail with reference to the drawings. In addition to the embodiments described below, the present invention can be claimed in various aspects including various modifications and improvements based on the knowledge of those skilled in the art, including the aspects described in the above [Aspect of the Invention] section. Can be implemented.

(A) First Example << Configuration of Vehicle Steering Device >>
FIG. 1 schematically shows a vehicle steering apparatus according to a first embodiment. The steering device 10 includes a steering wheel 12 as a steering operation member that is rotated by a driver, a steering shaft 14 that transmits an operation force applied to the steering wheel 12, and a steering device 16 that steers the wheel. It consists of The steering shaft 14 is connected to a steering main shaft (hereinafter also simply referred to as “main shaft”) 18 as an operation member side shaft member to which the steering wheel 12 is attached at one end, and a steering device 16 at one end. And an intermediate shaft (hereinafter referred to as “I / M shaft”) as an intermediate shaft member positioned between the main shaft 18 and the input shaft 20. And 22). Furthermore, the end of the main shaft 18 on which the operating member is not attached and the one end of the I / M shaft 22 are connected by a universal joint 24 that functions as a universal joint, and is connected to the steering device 16 of the input shaft 20. The other end of the I / M shaft 22 and the other end of the I / M shaft 22 are connected by another universal joint 26. Note that the steering shaft 14 is disposed so as to extend in the front-rear direction of the vehicle in an inclined posture so that the front end portion is positioned below the rear end portion. Therefore, in this embodiment, in consideration of simplification, the terms “front” and “rear” are used when expressing the steering shaft 14 and the portions, arrangements, and the like of the shafts 18, 20, and 22 constituting the steering shaft 14.

  The main shaft 18 is rotatably held in a state where it penetrates the inside of the column tube 30 as a tube member. A steering column 32 is configured including the main shaft 18 and the column tube 30, and the steering column 32 is mounted on the vehicle body by a bracket 34 provided on the column tube 30 at a substantially central portion in the axial direction of the column tube 30. Is attached. As shown in FIG. 2, the main shaft 18 includes a pipe-like upper shaft 50, a rod-like lower shaft 52, a torsion bar 54, and an output shaft 56. The steering wheel 12 is attached to the rear end portion of the upper shaft 50, while the rear portion of the lower shaft 52 is inserted into the front portion of the upper shaft 50, and these are relatively connected by spline fitting. Non-rotatable and relatively movable. The torsion bar 54 functions as a torsion portion of the steering shaft, and the lower shaft 52 is connected to the output shaft 56 via the torsion bar 54 at the front end portion thereof. The front end of the output shaft 56 is connected to the I / M shaft 22 via the joint 24. On the other hand, the column tube 30 is configured to include an upper tube 60 and a lower tube 62, and a rear portion of the lower tube 62 is inserted into a front portion of the upper tube 30 positioned rearward. Relative movement is possible in the direction. With such a structure, the steering column 32 can be expanded and contracted.

  The steering column 32 is provided with a steering assist device 70 at the front portion thereof for applying a rotational force to the main shaft 18 to assist the steering of the wheels. Specifically, a housing 71 as an outer shell member of the steering assist device 70 is fixed to the front end portion of the lower tube 62. As shown in FIG. The housing 71 includes an electric motor 72 as a power source, a worm 74 that is rotated by the electric motor, and a worm wheel 76 that meshes with the worm 74. A shaft hole 78 is formed at the center of the worm wheel 76, and the output shaft 56 is fixedly inserted into the shaft hole 78, and both the worm wheel 76 and the output shaft 56 rotate within the housing 71. It is possible. The force generated by the electric motor 72 is transmitted by a worm gear mechanism including a worm 74 and a worm wheel 76 to assist the rotation of the output shaft 56. That is, a rotational force (hereinafter sometimes referred to as “assist force”) on the output shaft 56 is applied to a portion that is fitted in the shaft hole 78 of the output shaft 56.

  As shown in FIG. 4, the I / M shaft 22 includes a pipe member 80 located on the rear side and a rod member 82 located on the front side. The rear end of the pipe member 80 is connected to the front end of the output shaft 56 via the joint 24, and the front end of the rod member 82 is connected to the rear side of the input shaft 20 via the joint 26. Connected to the end. On the other hand, the rear part of the rod member 82 is inserted into the front part of the pipe member 80, and the pipe member 80 and the rod member 82 cannot be rotated relative to each other by being spline-fitted. In addition, relative movement in the axial direction is possible. With such a structure, the I / M shaft 22 can be expanded and contracted.

  As described above, since the steering column 32 and the I / M shaft 22 can be extended and contracted, the position of the steering wheel 12 can be changed by the tilt / telescopic mechanism (not shown) of the steering apparatus 10. Is done. Further, for example, when the driver has a secondary collision with the steering wheel 12 due to a vehicle collision, the steering column 32 is contracted and the impact of the secondary collision is weakened. Further, for example, when the steering device 16 is displaced rearward due to a vehicle collision, the I / M shaft 22 is contracted, and the rearward displacement of the main shaft 12 is prevented or suppressed.

  The steered device 16 includes a housing 90 as an outer shell member and a steered rod 92 for steering a wheel, and the steered rod 92 has an axial direction as shown in FIG. The housing 90 is movably held in the housing 90 and extends in the vehicle width direction through the housing 90. Both ends of the steered rod 92 are connected via a tie rod 94 to a steering knuckle (not shown) that holds each of the left and right front wheels. Further, as shown in FIG. 5, the input shaft 20 is rotatably held by the housing 90 and is engaged with the steered rod 92 in the housing 90. A pinion 96 is formed at a position where the input shaft 20 and the steered rod 92 are engaged, that is, a front end portion (a lower end portion in the drawing) of the input shaft 20. Since the rack 98 thus engaged is engaged with the pinion 96, the steered rod 92 and the input shaft 20 are engaged with each other.

  The pinion 96 and the rack 98 constitute a rack and pinion mechanism 100 as an operation conversion mechanism. By the rack and pinion mechanism 100, the rotation of the steering shaft 14 moves in the axial direction of the steered rod 92. Is converted to The housing 90 is provided with a steered rod pressing mechanism 102 for reliably engaging the pinion 96 and the rack 98. Specifically, the steering device housing 90 is provided with a guide tube 104 and a plunger 106 is disposed in the guide tube 104, and the plunger 106 is supported by a tube cover 107. The turning rod 92 is biased toward the pinion 96 by the elastic force.

  From the above structure, when the steering wheel 12 is rotated in the steering device 10, the steering shaft 14 is rotated by the operating force applied thereto. The rotation thereof is converted into an axial movement of the steered rod 92 by the rack and pinion mechanism 100. The steering knuckle is rotated by the movement of the steered rod 16 and the wheels are steered. In addition, when the torsion bar 54 is twisted by an operating force, the electric motor 72 of the steering assist device 70 is controlled and operated so as to exert a rotational torque corresponding to the amount of twist, and the assist force corresponding to the amount of twist is generated. It is applied to the steering shaft 14.

  In the present steering device 10, the steered range, which is the range in which the wheels can be steered, is limited by a stopper mechanism 110 as a rod operation limiting mechanism that limits the range of movement of the steered rod 92 in the axial direction. Specifically, as shown in FIG. 6, cup-shaped housing ends 112 are provided at both ends of the steered device housing 90 that holds the steered rod 92, and both ends of the steered rod 92. Extends through the bottom of the housing end 112. As described above, both ends of the extended steering rod 92 are swingably connected to the tie rod 94 via the ball joint, and the rod end 114 functioning as a socket portion of the ball joint is provided in the housing. It can be inserted into the end 112. A buffer rubber 116 is fixed to the inner bottom surface of the housing end 112. With such a structure, the rod end 114 abuts against the inner bottom surface of the housing end 112 via the shock absorbing rubber 116 in accordance with the operation of the steered rod, so that the moving range of the steered rod 92 is limited, and the wheel The steering range is limited.

  Further, the steering device 10 is a shaft rotation suppression mechanism (a type of shaft rotation suppression mechanism) that suppresses the rotation of the steering shaft 14 prior to the limitation of the turning range by the stopper mechanism 110. 120) (sometimes referred to as a “mechanism”). As shown in FIGS. 5 and 7, the rotation suppression mechanism 120 is screwed into a male screw 122 formed at a substantially central position in the axial direction of the outer peripheral portion of the input shaft 20 and the male screw 122 via a bearing ball. And a nut member 126 having an internal thread 124. A pair of grooves 128 are provided on the outer peripheral portion of the nut member 126 so as to extend in the axial direction, and each of the grooves 128 is provided on the inner wall surface of the housing 90 so as to extend in the axial direction. Each of the pair of guides 130 is fitted. An annular rubber member 132 as an elastic body is attached to both ends of the pair of guides 130, respectively.

  The nut member 126 functions as a moving body that moves in conjunction with the rotation of the input shaft 20. The nut member 126 moves along the guide 130 as the steering wheel 12 rotates, and contacts the rubber member 132 at a certain rotation operation position. Touch. More specifically, the nut member 126 contacts the rubber member 132 before the rod end 114 of the steering rod 92 contacts the housing end 112 in the stopper mechanism 110 described above. In the present steering device 10, the rubber member 132 imparts an elastic force to the nut member 126 as the nut member 126 and the rubber member 132 come into contact with each other, thereby restricting the turning range by the stopper mechanism 110. Before, resistance is given to operation of nut member 126, and rotation of input shaft 20 is controlled. Further, in the present steering device 10, before the rubber member 132 is crushed by the nut member 126, in other words, before the rotation suppression mechanism 120 restricts the rotation of the input shaft 20 (that is, the rotation suppression mechanism 120 causes the input shaft 20 Before the rotation is prohibited, the rod end 114 comes into contact with the housing end 112, and the turning range is limited by the stopper mechanism 110. As described above, the present steering device 10 is configured such that the rotation of the steering shaft 12 is suppressed before the steering range of the wheel is limited by the stopper mechanism 110, that is, prior to the limitation of the steering range. It has been done.

≪Load on the steering device when limiting the steering range of the wheel≫
In the present steering device 10, as described above, the rotation of the shaft is suppressed before the wheel turning range is limited. In a steering apparatus that does not include 120, the steered range of the wheels is limited by simply limiting the operation of the steered rod by a mechanism similar to the stopper mechanism 110 described above. In such a general steering apparatus, when the wheel turning range is limited, an impact force acts on the rack and pinion mechanism by the inertial force of the steering wheel 12 and the electric motor 72. Further, when the turning range is limited, twist remains in the torsion bar, and the assist force corresponding to the twist amount acts as an impact force on the rack and pinion mechanism immediately after the limit. Such an impact force becomes a load on the rack and pinion mechanism.

  In consideration of such a load on the rack and pinion mechanism, the steering device 10 is provided with the rotation suppression mechanism 120. That is, before the stopper mechanism 110 limits the steered range of the wheel, the rotation suppression mechanism 120 suppresses the rotation of the steering shaft 14 and the load on the rack and pinion mechanism is reduced. is there. In addition, since the location where rotation is suppressed by the rotation suppression mechanism 120 in the steering shaft 14 is a portion ahead of the location where the assist force is applied by the steering assist device 70, the inertia force of the electric motor 72 described above. , The impact force to the rack and pinion mechanism due to the assist force based on the twist of the torsion bar can be effectively reduced.

  Further, in the present steering device 10, even when the wheel is steered by an external input from the wheel caused by road surface unevenness or the like, the operation range of the steered rod 92 is limited by the stopper mechanism 110, and the wheel is turned. Rudder range is limited. Even when the turning is restricted under the action of such an external input, the rotation of the steering shaft 14 is suppressed by the rotation suppression mechanism 120 prior to the limitation, and the load on the rack and pinion mechanism is reduced. It will be. Further, when an external input for turning the wheel beyond the steering range is applied, the operation range of the steering rod 92 is limited by the stopper mechanism 110, and the external input is It hardly acts on the pinion mechanism, and the load on the rack and pinion mechanism in that case hardly occurs.

(B) Second Embodiment A vehicle steering device 10 ′ according to the present embodiment has an overall structure as shown in FIG. 1 as with the previous steering device 10. In contrast, the steering range of the wheel is limited by limiting the rotation range of the steering shaft 14. That is, the present steering device 10 ′ replaces the shaft rotation suppression mechanism 120 provided in the previous steering device 10, and restricts the rotation range of the steering shaft 14 to limit the steering range (of the shaft rotation suppression mechanism). It is a kind). The present steering device 10 ′ has substantially the same configuration as the steering device 10 described above, except for the stopper mechanism. Therefore, in the description of the present device 10 ′, the stopper mechanism will be mainly described. Constituent elements common to the previous apparatus 10 are denoted by the same reference numerals, and description thereof is omitted or simplified. In the present steering device 10 ′, a stopper mechanism that restricts the rotation of the steering shaft 14 is provided. Therefore, as shown in FIG. Stopper mechanism is not provided.

  As shown in FIG. 9, the stopper mechanism 140 provided in the present steering device is provided in the housing 90 of the steering device 16 in the same manner as the rotation suppression mechanism 120 provided in the previous steering device 10. The stopper mechanism 140 includes a male screw 141 formed at a substantially central position in the axial direction of the outer peripheral portion of the input shaft 20, and a nut member 144 having a female screw 142 screwed with the male screw 141 via a bearing ball. It is configured. A pair of grooves 145 are provided on the outer peripheral portion of the nut member 144 so as to extend in the axial direction, and each of the grooves 145 is provided on the inner wall surface of the housing 90 so as to extend in the axial direction. Each of the pair of guides 146 is fitted. An annular member 147 is fixed to both ends of the pair of guides 146, respectively, and an annular buffer rubber 148 is attached to each of the pair of annular members 147.

  The nut member 144 functions as a moving body that moves in conjunction with the rotation of the input shaft 20. The nut member 144 moves along the guide 146 as the steering wheel 12 rotates. At a certain rotational operation position, the nut member 144 passes through a buffer rubber 148. In contact with the annular member 148. Therefore, the annular member 148 functions as a movement restricting body that restricts the movement range of the nut member 144, and the rotation range of the input shaft 20 is limited. Therefore, the steering device 10 ′ is configured such that the wheel turning range is limited by the stopper mechanism 140. Note that, unlike the rubber member 132 included in the previous rotation suppression mechanism 120, the buffer rubber 148 included in the stopper mechanism 140 has a reduced thickness. Therefore, in this stopper mechanism 140, the rotation suppression effect of the input shaft 20 before the turning range is limited is considerably smaller than that of the rotation suppression mechanism 120.

  In the present steering device 10 ′, the portion of the steering shaft 14 whose rotation is restricted by the stopper mechanism 140 is a portion ahead of the portion where the assist force is applied by the steering assist device 70, and the steering rod Since the moving range of 92 is not limited, when the steering range of the wheel is limited, the inertia force of the steering wheel 12 and the electric motor 72, the assist force based on the torsion bar torsion, etc. are hardly applied to the rack and pinion mechanism 100. Does not work. Accordingly, the load on the rack and pinion mechanism 100 when the wheel turning range is limited hardly occurs. However, this is an advantage in the case where the steering range of the wheel is limited with respect to the operation of the steering wheel 12, and in the case where the steering range of the wheel is limited by the action of the external input described above. Cannot enjoy the benefits. That is, in the present steering device 10 ′, the load on the rack and pinion mechanism when the wheel turning range is limited by the action of an external input is larger than that of the previous steering device 10. .

(C) Third Embodiment Similar to the steering device 10 of the first embodiment, the vehicle steering device of the present embodiment rotates the main shaft instead of the input shaft before the wheel turning range is limited. A steering device configured to suppress. FIG. 10 schematically shows the vehicle steering apparatus 150 of the present embodiment. Since the present steering device 150 includes many components common to the steering device 10 described above, the same reference numerals are used for the components common to the previous device 10 in the description of the device 150. The description of will be omitted or simplified.

  A steering shaft 152 included in the steering device 150 is connected to a steering main shaft (hereinafter sometimes simply referred to as “main shaft”) 154 attached to the steering wheel 12 at one end portion and a steering device 155 at one end portion. It includes an input shaft 156 and an intermediate shaft (hereinafter also abbreviated as “I / M shaft”) 158 located between the main shaft 154 and the input shaft 156.

  As shown in FIG. 11, the steering device 155 includes a housing 160 as an outer shell member and a steering rod 92. Similar to the input shaft 20 of the steering apparatus 10, the input shaft 156 is rotatably held by the housing 160 and is engaged with the steered rod 92 by the rack and pinion mechanism 100. Stopper mechanisms 110 are provided at both ends of the housing 160 where the steered rod 92 extends (see FIG. 11).

  As shown in FIG. 12, the main shaft 154 passes through the inside of the column tube 170 and is rotatably supported by the main shaft 154. The main shaft 154 includes the main shaft 154 and the column tube 160 to form a steering column 172. Yes. The steering column 172 has a structure provided with a shaft rotation suppression mechanism (a type of shaft rotation suppression mechanism, which may be simply referred to as “rotation suppression mechanism” hereinafter) 174 that suppresses rotation of the main shaft 154. . Specifically, the rotation suppression mechanism 174 includes a male screw 180 formed at a substantially central position in the axial direction of the outer peripheral portion of the output shaft 176 constituting the main shaft 154, and the male screw 180 and the screw through a bearing ball. And a nut member 184 having a mating female screw 182. A pair of grooves 186 are provided on the outer peripheral portion of the nut member 184 so as to extend in the axial direction, and each of the grooves 186 extends in the axial direction on the inner wall surface of the housing 188 of the steering assist device 70. Each of the pair of guides 190 provided in this way is fitted. An annular rubber member 192 as an elastic body is attached to both ends of the pair of guides 190.

  The nut member 184 functions as a moving body that moves in conjunction with the rotation of the output shaft 176. The nut member 184 moves along the guide 190 in accordance with the rotation operation of the steering wheel 12, and contacts the rubber member 192 at a certain rotation operation position. Touch. More specifically, in the present steering device 150, as in the previous steering device 10, the nut member 184 is moved before the contact of the rod end 114 of the steered rod 92 to the housing end 112 in the stopper mechanism 110. It contacts the rubber member 192. Thus, the present steering apparatus 150 is also configured such that the rotation of the steering shaft 14 is suppressed before the wheel turning range is limited by the stopper mechanism 110, that is, prior to the limitation of the turning range. It has been done.

  With this structure, before the steering range of the wheel is limited by the stopper mechanism 110, the rotation of the steering shaft 14 is suppressed by the rotation suppression mechanism 174, and the load on the rack and pinion mechanism 100 is reduced. It is alleviated. It should be noted that the portion of the steering shaft 14 whose rotation is suppressed by the rotation suppression mechanism 120 is a portion in front of the portion where the assist force is applied by the steering assist device 70, and the main shaft 154 and the I / M shaft 158 are connected. It is between the parts to be done. Therefore, in the present steering device 150, when the turning range is limited, not only the load on the rack and pinion mechanism 100 but also the load on the I / M shaft 158, the input shaft 156, the universal joints 24, 26, etc. Has also been reduced.

  In the present steering device 150 as well, as in the previous steering device 10, the rack and pinion mechanism 100 is also used when turning is restricted under the action of external input from the wheels caused by unevenness on the road surface. The load on the rack and pinion mechanism 100 is hardly generated even when an external input is applied to steer the wheel beyond the turning range.

(D) Fourth Embodiment A vehicle steering apparatus 150 ′ according to the present embodiment has the structure shown in FIG. 10 similarly to the steering apparatus 150 according to the third embodiment, and limits the rotation range of the steering shaft 152. Thus, the steering device is configured to limit the steered range of the wheels. This steering apparatus 150 ′ includes a stopper mechanism (a kind of shaft rotation suppression mechanism) that limits the rotation range of the steering shaft 14 instead of the shaft rotation suppression mechanism 174 provided in the previous steering apparatus 150. Since this steering device 150 ′ has substantially the same configuration as the steering device 150 described above except for the stopper mechanism, the description of this device will be focused on the stopper mechanism, and the previous device will be described. Constituent elements common to 150 are denoted by the same reference numerals, and description thereof is omitted or simplified. Note that, in the present steering device, a stopper mechanism for limiting the movement range of the steered rod 92 is not provided as in the steering device 10 ′ of the second embodiment.

  As shown in FIG. 13, the stopper mechanism 200 provided in the present steering device 150 ′ is provided in the housing 188 of the steering assist device 70 in the same manner as the rotation suppression mechanism 174 provided in the previous steering device 150. The stopper mechanism 200 includes a male screw 202 formed at a substantially central position in the axial direction of the outer peripheral portion of the output shaft 176, and a nut member 206 having a female screw 204 screwed to the male screw 202 via a bearing ball. It is configured. A pair of grooves 208 are provided on the outer peripheral portion of the nut member 206 so as to extend in the axial direction. Each of the grooves 208 is provided on the inner wall surface of the housing 188 so as to extend in the axial direction. Each of the pair of guides 210 is fitted. An annular member 212 is fixed to both ends of the pair of guides 210, and an annular cushioning rubber 214 is attached to each of the pair of annular members 212.

  The nut member 206 functions as a moving body that moves in conjunction with the rotation of the output shaft 176, moves along the guide 210 with the rotation operation of the steering wheel 12, and passes through the buffer rubber 214 at a certain rotation operation position. Then, it abuts on the annular member 212. Therefore, the annular member 212 functions as a movement restricting body that restricts the movement range of the nut member 206, and the rotation range of the output shaft 176 is limited. Therefore, in the present steering device 150 ′, the steered range of the wheels is limited by the stopper mechanism 200 having such a structure. In the stopper mechanism 200, the rotation suppression effect of the output shaft 176 before the turning range is limited is considerably smaller than that of the rotation suppression mechanism 174.

  In the present steering device 150 ′, the rotation is restricted by the stopper mechanism 200 at the same location where the rotation of the steering shaft 14 of the previous steering device 150 is suppressed. Thus, the load on the rack and pinion mechanism 100 is hardly generated. Furthermore, almost no load is applied to the I / M shaft 158, the input shaft 156, and the like. However, as described above, the load on the rack and pinion mechanism 100 when the wheel turning range is limited by the action of an external input is larger than that of the steering device 150 described above.

It is a mimetic diagram showing the whole steering device composition of the 1st example. It is a schematic sectional drawing which shows the steering column which comprises the steering apparatus of 1st Example. It is a schematic sectional drawing which shows the steering assistance apparatus which comprises the steering apparatus of 1st Example. It is a schematic sectional drawing which shows the intermediate shaft which comprises the steering apparatus of 1st Example. It is a schematic sectional drawing which shows the steering apparatus which comprises the steering apparatus of 1st Example. It is a schematic sectional drawing which shows the stopper mechanism which comprises the steering apparatus of 1st Example. It is a schematic sectional drawing which shows the shaft rotation suppression mechanism which comprises the steering apparatus of 1st Example. It is a schematic sectional drawing which shows the edge part of the steering rod which comprises the steering apparatus of 2nd Example. It is a schematic sectional drawing which shows the steering apparatus which comprises the steering apparatus of 2nd Example. It is a schematic diagram which shows the whole structure of the steering device of 3rd Example. It is a schematic sectional drawing which shows the steering apparatus which comprises the steering apparatus of 3rd Example. It is a schematic sectional drawing which shows the steering column which comprises the steering apparatus of 3rd Example. It is a schematic sectional drawing which shows the steering column which comprises the steering apparatus of 4th Example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10, 10 ': Steering device for vehicles 12: Steering wheel (steering operation member) 14: Steering shaft 18: Steering main shaft (operation member side shaft member) 20: Input shaft (steering rod side shaft member) 22: Intermediate Eight shaft (intermediate shaft member) 24: universal joint (first universal joint) 26: universal joint (second universal joint) 30: column tube (tube member) 32: steering column 54: torsion bar (torsion part) 70: rolling Rudder assist device 72: Electric motor (power source) 90: Housing 92: Steering rod 96: Pinion 98: Rack 100: Rack and pinion mechanism (motion conversion mechanism) 110: Stopper Structure (rod motion limiting mechanism) 120: Shaft rotation suppression mechanism (shaft rotation suppression mechanism) 122: Male screw 124: Female screw 126: Nut member (moving body) 132: Rubber member (elastic body) 140: Stopper mechanism (shaft rotation suppression mechanism) 141: Male screw 142: Female screw 144: Nut member (moving body) 147: Annular member (movement restricting body) 150, 150 ': Vehicle steering device 152: Steering shaft 154: Steering main shaft (operation member side shaft member) 156 : Input shaft (steering rod side shaft member) 158: intermediate shaft (intermediate shaft member) 160: housing 170: column tube (tube member) 172: steering column 174: shaft Rotation suppression mechanism (shaft rotation suppression mechanism) 180: male screw 182: female screw 184: nut member (moving body) 192: shock absorbing rubber (elastic body) 200: stopper mechanism (shaft rotation suppression mechanism) 202: male screw 204: female screw 206: nut Member (moving body) 212: annular member (movement restricting body)

Claims (8)

A steering rod that connects the left and right wheels and steers the left and right wheels by movement in the axial direction;
A steering operation member that is rotated by a driver;
A steering shaft that is attached to one end of the steering operation member, engages with the steered rod at the other end, and rotates by rotation of the steering operation member;
An operation conversion mechanism provided at a position where the steering shaft and the steered rod engage with each other, and converting the rotation of the steering shaft into an axial movement of the steered rod;
A steering assist device that has a power source and assists the steering of the wheel by applying a rotational force to the steering shaft at an intermediate portion of the steering shaft;
A vehicle steering apparatus comprising: a shaft rotation suppression mechanism that suppresses rotation of the steering shaft between a portion of the steering shaft to which a rotational force is applied by the steering assist device and the motion conversion mechanism .   The vehicle steering according to claim 1, wherein the motion conversion mechanism includes a rack provided on the steered rod and a pinion provided on the other end portion of the steering shaft and meshing with the rack. apparatus. The vehicle steering apparatus includes a tube member that is supported by a vehicle body and rotatably holds a portion of the steering shaft that is close to the steering operation member, and the tube member and the steering are provided. A steering column including a portion of the shaft closer to the steering operation member,
The steering assist device is provided in the steering column and applies a rotational force to a portion of the steering shaft closer to a steering operation member;
The shaft rotation inhibiting mechanism, the provided on the steering column, in the vicinity of the location where the rotational force is applied by the steering assist device of the steering shaft, claims wherein is intended to suppress the rotation of the tearing shaft The vehicle steering apparatus according to claim 1 or 2 . The vehicle steering device is
A housing fixed to a vehicle body, holding the steered rod movably in the axial direction thereof, holding the other end of the steering shaft rotatably, and including the motion conversion mechanism;
The vehicle steering device according to claim 1, wherein the shaft rotation suppression mechanism is provided in the housing and suppresses rotation of the steering shaft in the vicinity of the motion conversion mechanism . The vehicle steering device is
The vehicle steering apparatus according to any one of claims 1 to 4 , wherein the shaft rotation suppression mechanism limits a rotation range of the steering shaft so that a wheel turning range is limited . A moving body that engages with the steering shaft and moves in conjunction with rotation of the steering shaft; and a movement restricting body that abuts the moving body and restricts the movement of the moving body. The vehicle steering apparatus according to claim 5 , comprising: The vehicle steering apparatus includes a rod operation restriction mechanism that restricts a steered range of a wheel by restricting an operation range of the steered rod by contacting a part of the steered rod;
The shaft rotation inhibiting mechanism, the prior by rod operation limiting mechanism to limit the turning range of the wheel, claim is intended to inhibit the rotation of the steering shaft by providing resistance to rotation of the steering shaft 1 The vehicle steering device according to any one of claims 4 to 4 . The shaft rotation suppression mechanism is elastically deformed by the moving body that engages with the steering shaft and moves in conjunction with the rotation of the steering shaft, and the movement of the moving body in contact with the moving body. And an elastic body that gives elastic force to the moving body,
The vehicle steering apparatus according to claim 7 , wherein the rod operation restriction mechanism restricts an operation range of the steered rod in a state where an elastic force is applied to the moving body.

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