JP2019151152A - Steering gear - Google Patents

Abstract

To provide a small-sized steering gear capable of recognizing that a driver reaches a steering limit.SOLUTION: A steering gear includes: a steering shaft 21 rotating together with a steering wheel 11 operated by a driver; a feed nut 31 arranged with the steering shaft 21 centered; a rotation-slide mechanism which rotates the steering shaft 21 and the feed nut 31 together in the peripheral direction and permits the feed nut 31 to slide in the axial direction relative to the steering shaft 21; a cylindrical member 41 arranged to surround the feed nut 31 and is under a non-rotation state; a feed mechanism for axially feeding the feed nut 31 to the steering shaft 21 by a rotational movement of the feed nut 31 relative to the cylindrical member 41; and an upper stopper 43A and a lower stopper 43B which are arranged on both sides of the feed nut 31, respectively and regulates an axial slide movement of the feed nut 31 by an abutment of the feed nut 31.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a steering apparatus.

  In a steering device of SBW (Steer By Wire) method, a steering wheel operated by a driver and a rack shaft that steers a steering wheel are not mechanically connected to each other (see Patent Document 1).

Japanese Patent Laying-Open No. 2006-164017

  Thus, since the steering wheel and the rack shaft are not connected to each other in the SBW type steering device, the driver cannot recognize that the rack end integral with the rack shaft is in contact with the stopper and reaches the steering limit. There is a fear. In this case, the driver may further rotate the steering wheel.

  Therefore, a configuration is conceivable in which the output (torque) of the reaction force motor (reaction force actuator) that applies reaction force to the steering wheel is increased near the steering limit. However, if constituted in this way, the reaction force motor will become large and difficult to mount on the vehicle.

  Therefore, an object of the present invention is to provide a small steering device that allows the driver to recognize the arrival of the steering limit.

  As means for solving the above problems, the present invention provides a steering shaft that rotates integrally with an operating member operated by a driver, an annular member disposed around the steering shaft, the steering shaft, and the annular member. And a rotation-slide mechanism that allows the annular member to slide in the axial direction relative to the steering shaft, and a cylinder that is disposed so as to surround the annular member and is in a non-rotating state And a feed mechanism for feeding the annular member in the axial direction relative to the steering shaft by rotational movement of the annular member relative to the tubular member, and an annular member disposed on both sides of the annular member in the axial direction. And a regulating member that regulates the sliding movement of the annular member in the axial direction by contacting the member. It is a device.

  According to such a configuration, when the operation member operated by the driver and the steering shaft rotate together, the rotation-slide mechanism rotates the steering shaft and the annular member integrally in the circumferential direction. Note that the rotation-slide mechanism allows the annular member to slide in the axial direction with respect to the steering shaft.

  When the annular member rotates with respect to the non-rotating cylindrical member, the feed mechanism sends the annular member in the axial direction with respect to the steering shaft. Next, when the annular member comes into contact with the restricting member, the sliding movement of the annular member in the axial direction is restricted. In this way, when the annular member is restricted from sliding in the axial direction, the annular member cannot rotate, and the steering shaft and the operation member integrated with the annular member also cannot rotate. When the operation member becomes non-rotatable in this way, the driver can recognize that the steering limit has been reached.

  Such a steering device is small because it can be configured by including an annular member, a rotary slide mechanism, a feed mechanism, and a regulating member.

  ADVANTAGE OF THE INVENTION According to this invention, the small steering device which a driver | operator can recognize reaching | attaining to a steering limit can be provided.

It is a lineblock diagram of the steering device concerning this embodiment. It is a longitudinal cross-sectional view of the principal part of the steering apparatus which concerns on this embodiment, and has shown the neutral time. It is a longitudinal cross-sectional view of the principal part of the steering device which concerns on this embodiment, and has shown the time of left rotation. It is a longitudinal cross-sectional view of the principal part of the steering apparatus which concerns on this embodiment, and has shown the time of right rotation.

  An embodiment of the present invention will be described with reference to FIGS.

≪Configuration of steering device≫
The steering device 100 according to the present embodiment is a device that steers the left front wheel 302A and the right front wheel 302B (steering wheel) of the four-wheeled vehicle based on a driver's operation. Further, the steering device 100 is an SBW system, and the steering wheel 11 and the rack shaft 131 are in a disconnected state in a normal state.

  The steering device 100 includes a steering wheel 11, a steering shaft 21, a reaction force motor 24, a stopper mechanism 30, a clutch 110, a first pinion shaft 121, a rack shaft 131, a second pinion shaft 141, and a steering. A motor 145, an angle sensor 151, and the like, and an ECU 200 (Electronic Control Unit) are provided. That is, the steering device 100 is a dual pinion system including a first pinion shaft 121 and a second pinion shaft 141, and the steering force of the steering motor 145 is input to the rack shaft 131 via the second pinion shaft 141. is there. However, other than this, for example, the second pinion shaft 141 is not provided, and the steering force of the steering motor 145 is input to the first pinion shaft 121, or the steering force of the steering motor 145 is input to the rack shaft 131. A rack assist method may be used.

  The steering wheel 11 is an operation member operated by the driver.

  The steering shaft 21 is an elongated cylindrical member, and is rotatably supported on the vehicle body via a bearing (not shown). The upper end of the steering shaft 21 is connected to the steering wheel 11, and the steering shaft 21 and the steering wheel 11 rotate integrally. The lower end of the steering shaft 21 is connected to the clutch 110. However, the steering shaft 21 may have a configuration in which a plurality of shaft members are connected via a universal joint or the like.

  The reaction force motor 24 is a motor that applies a reaction force to the steering shaft 21 in accordance with a command from the ECU 200. The reaction force is a force in a direction opposite to the rotational force of the steering shaft 21 that is rotated by a driver's operation. Specifically, a worm 23 fixed to the output shaft of the reaction force motor 24 meshes with a worm wheel 22 fixed to the steering shaft 21. When the reaction force motor 24 is driven, a reaction force is input to the steering shaft 21 so that the driver can obtain a steering feeling. Here, a worm gear mechanism including a worm wheel 22 and a worm 23 is used as a speed reduction mechanism that decelerates the rotational force of the reaction force motor 24 and inputs it to the steering shaft 21, but other known speed reduction mechanisms are used. You can also. For example, a belt mechanism composed of two large and small pulleys and a belt suspended between both pulleys can be used as the speed reduction mechanism.

  Clutch 110 is a connection / disconnection device that disconnects / connects power between steering shaft 21 and first pinion shaft 121 in accordance with a command from ECU 200. As the clutch 110, for example, a clutch described in Japanese Patent Application Laid-Open No. 2017-180615 or Japanese Patent Application Laid-Open No. 2017-180614, a lock structure described in Japanese Patent Application Laid-Open No. 2015-16827, and other planetary gear mechanisms can be used.

  Specifically, the clutch 110 is controlled to be disconnected by the ECU 200 during normal times. As a result, the steering shaft 21 and the first pinion shaft 121 are normally rotatable relative to each other, and the operating force of the driver is not input to the first pinion shaft 121.

  On the other hand, the clutch 110 is controlled to be in a connected state by the ECU 200 at the time of abnormality or failure. The abnormal time is, for example, when an excessive operation torque is input when an excessive operation torque is input from the driver. The failure time is, for example, when the reaction force motor 24, the steering motor 145, or the angle sensor 151 fails, or when the power source of the reaction force motor 24 or the like is lost. As a result, the steering shaft 21 and the first pinion shaft 121 are unable to rotate relative to each other during an abnormality or failure, that is, rotate together, and the driver's operating force is input to the first pinion shaft 121.

  The first pinion shaft 121 is an elongated cylindrical member, and is rotatably supported by the vehicle body via a bearing (not shown). A first pinion 122 is formed at the lower end of the first pinion shaft 121, and the first pinion 122 meshes with a first rack 132 described later.

  The rack shaft 131 is an elongated rod-like member extending in the vehicle width direction, and is slidably accommodated in a cylindrical housing 134 via a bush (not shown). A first rack 132 and a second rack 133 are formed on the rack shaft 131.

  A left rack end 135 </ b> A is fixed to the left end of the rack shaft 131. The left rack end 135A is connected to the left front wheel 302A via a left tie rod 301A. A right rack end 135 </ b> B is fixed to the right end of the rack shaft 131. The right rack end 135B is connected to the right front wheel 302B via the right tie rod 301B. A rubber left stopper 136A having a ring shape is fixed to the left end of the housing 134. Similarly, a right stopper 136B is fixed to the right end.

  When the driver turns the steering wheel 11 counterclockwise when turning left, the rack shaft 131 slides to the right, and the left front wheel 302A and the right front wheel 302B are steered. In this case, when the left rack end 135A comes into contact with the left stopper 136A, the left steering limit is reached.

  On the other hand, when the driver turns the steering wheel 11 to the right when turning right, the rack shaft 131 slides to the left, and the left front wheel 302A and the right front wheel 302B are steered. In this case, when the right rack end 135B contacts the right stopper 136B, the right steering limit is reached.

  The second pinion shaft 141 is an elongated cylindrical member, and is rotatably supported by the housing 134 via a bearing (not shown). A second pinion 142 is formed at the lower end of the second pinion shaft 141, and the second pinion 142 meshes with the second rack 133.

  The steering motor 145 is a motor that applies a steering force to the rack shaft 131 in accordance with a command from the ECU 200. The steering force is a force for steering the left front wheel 302A and the right front wheel 302B. Specifically, a worm 144 fixed to the output shaft of the reaction force motor 24 meshes with a worm wheel 143 fixed to the second pinion shaft 141. When the steering motor 145 is driven, a steering force is input to the rack shaft 131.

  The angle sensor 151 detects the operation angle of the steering shaft 21 and outputs it to the ECU 200. The torque sensor 152 detects an operation torque input from the driver to the steering shaft 21 and outputs the detected operation torque to the ECU 200. The vehicle speed sensor 153 detects the vehicle speed and outputs it to the ECU 200.

  The ECU 200 is a control device that electronically controls the steering device 100, and includes a CPU, a ROM, a RAM, various interfaces, an electronic circuit, and the like, and controls various devices in accordance with programs stored therein. Various processes are executed.

  Specifically, the ECU 200 drives the reaction force motor 24 and the steering motor 145 based on the operation angle, the operation torque, and the vehicle speed. The ECU 200 also has a function of controlling the clutch 110 to be ON (connected) / OFF (disconnected).

  Furthermore, for example, when the operation angle per predetermined time is equal to or greater than the predetermined operation angle, the ECU 200 determines that the excessive operation torque is being input, and is set to turn on the clutch 110. As a result, the steering shaft 21 and the first pinion shaft 121 are connected, and the left front wheel 302A and the right front wheel 302B are steered without delay from the driver's operating force.

<Stopper mechanism>
The stopper mechanism 30 is a mechanism that restricts excessive rotation of the steering shaft 21. As shown in FIGS. 1 and 2, the stopper mechanism 30 includes a part of the steering shaft 21, a feed nut 31 (annular member), a cylindrical member 41, an upper stopper 43A, and a lower stopper 43B. ing.

  A shaft spline 25 is formed on the outer peripheral surface of the steering shaft 21. The feed nut 31 is an annular member disposed around the steering shaft 21, and a hole spline 32 is formed on the inner peripheral surface thereof. The hole spline 32 is combined with the shaft spline 25. That is, the steering shaft 21 and the feed nut 31 are spline-coupled.

  As a result, the steering shaft 21 and the feed nut 31 rotate integrally in the circumferential direction, and the feed nut 31 can slide in the axial direction with respect to the steering shaft 21. That is, in the rotation-slide mechanism that allows the steering shaft 21 and the feed nut 31 to rotate integrally in the circumferential direction and that allows the feed nut 31 to slide relative to the steering shaft 21, the steering shaft 21 and the feed nut 31 are spline-coupled. It is composed of that.

  Thus, since the steering shaft 21 and the feed nut 31 are spline-coupled, even if a torsional torque acts on the steering shaft 21, the slidability of the feed nut 31 with respect to the steering shaft 21 is difficult to decrease. . On the other hand, when the feed nut 31 is screwed onto the steering shaft 21 with a screw, when a twisting torque is applied to the steering shaft 21, a screw pitch shift occurs, and the feed nut 31 slides in the axial direction. There is a possibility that the mobility (sliding property) is lowered.

  A male screw 33 that is a trapezoidal screw is formed on the outer peripheral surface of the feed nut 31. However, the male screw 33 and the female screw 42 to be described later may be, for example, a square screw or a round screw.

  The cylindrical member 41 is a cylindrical member disposed so as to surround the feed nut 31 and is a non-rotating member fixed to the vehicle body via a stay (not shown). A female screw 42 that is a trapezoidal screw is formed on the inner peripheral surface of the cylindrical member 41. The feed screw mechanism is configured by combining the female screw 42 with the male screw 33.

  That is, the feed screw mechanism is configured to feed the feed nut 31 in the axial direction by the rotational movement of the feed nut 31 with respect to the tubular member 41. In the present embodiment, when the feed nut 31 rotates counterclockwise, the feed nut 31 is fed upward in the axial direction (see FIG. 3). On the other hand, when the feed nut 31 rotates to the right, it is sent downward in the axial direction (see FIG. 4).

  The upper stopper 43 </ b> A and the lower stopper 43 </ b> B are arranged on both sides of the feed nut 31 in the axial direction, and are regulating members that regulate the sliding movement of the feed nut 31 in the axial direction when the feed nut 31 contacts.

  Specifically, the upper stopper 43 </ b> A has a ring shape and is fixed to the upper end surface of the tubular member 41 with a bolt or the like. When the feed nut 31 contacts the upper stopper 43A, the upward sliding movement of the feed nut 31 is restricted. Thereby, the left rotation of the steering shaft 21 is also restricted, and the driver recognizes the steering limit on the left rotation side. However, the shape of the upper stopper 43 </ b> A is not limited to this, and may be, for example, a protrusion that protrudes radially inward from the inner peripheral surface of the tubular member 41. The same applies to the lower stopper 43B.

  The timing at which the feed nut 31 contacts the upper stopper 43A is set substantially simultaneously with the timing at which the left rack end 135A contacts the left stopper 136A. However, for example, the feed nut 31 may contact the upper stopper 43A before the left rack end 135A contacts the left stopper 136A.

  Similarly, the lower stopper 43B has a ring shape and is fixed to the lower end surface of the cylindrical member 41 with a bolt or the like. When the feed nut 31 comes into contact with the lower stopper 43B, the downward sliding movement of the feed nut 31 is restricted. Thereby, the right rotation of the steering shaft 21 is also restricted, and as a result, the driver recognizes the steering limit on the right rotation side.

  The timing at which the feed nut 31 contacts the lower stopper 43B is set substantially simultaneously with the timing at which the right rack end 135B contacts the right stopper 136B. However, for example, the feed nut 31 may contact the lower stopper 43B before the right rack end 135B contacts the right stopper 136B.

≪Function and effect of steering device≫
The effects of the steering device 100 will be described.
When the driver turns the steering wheel 11 far left to make a large left turn, the steering shaft 21 and the feed nut 31 rotate left, and the feed nut 31 slides upward relative to the steering shaft 21 while rotating left. As shown in FIG. 3, when the feed nut 31 comes into contact with the upper stopper 43A, the driver recognizes the steering limit on the left rotation side and stops the left rotation of the steering wheel 11.

  As a result, the driver stops the left rotation of the steering wheel 11, so that the steering wheel 11 and the steering shaft 21 do not rotate excessively.

  Similarly, when the driver turns the steering wheel 11 to the right to make a large right turn, the steering shaft 21 and the feed nut 31 rotate to the right, and the feed nut 31 slides downward with respect to the steering shaft 21 while rotating to the right. Moving. As shown in FIG. 4, when the feed nut 31 comes into contact with the lower stopper 43B, the driver recognizes the steering limit on the right rotation side and stops the left rotation of the steering wheel 11.

  Conventionally, for example, when it is determined that the left rack end 135A is in contact with the left stopper 136A, or when excessive operation torque is input (when excessive operation torque is input), the steering wheel 11 and the like thereafter In order to prevent excessive rotation, the clutch 110 is turned on (connected). However, according to the present embodiment, it is not necessary to turn on the clutch 110, so that the control process of the clutch 110 is simplified. Furthermore, since an excessive operation torque is not input to the clutch 110, the clutch 110 can be reduced in size.

  Further, since the stopper mechanism 30 can be constituted by the feed nut 31, the cylindrical member 41, the upper stopper 43A, and the lower stopper 43B, the steering device 100 is not increased in size. That is, it is not necessary to increase the size of the reaction force motor 24 so that the steering limit can be recognized. Furthermore, the shaft spline 25 can also be used as a shaft spline constituting a telescopic structure, and can be configured simply.

≪Modification≫
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to this, For example, you may change as follows.

  In the above-described embodiment, the configuration in which the stopper mechanism 30 is disposed between the worm wheel 22 for the reaction force motor 24 and the clutch 110 is illustrated, but other layouts may be used. For example, the stopper mechanism 30 may be arranged between the steering wheel 11 and the worm wheel 22 (reaction force motor 24).

  In the above-described embodiment, the rotation-sliding mechanism is exemplified by the configuration in which the steering shaft 21 and the feed nut 31 are spline-coupled, but may be configured as follows. For example, a part of the steering shaft 21 may be cut out in a sectional view to form a notch, and the inner peripheral surface of the feed nut 31 may be formed so as to correspond to the notch. Alternatively, one or a plurality of keys extending in the axial direction may be protruded from the outer peripheral surface of the steering shaft 21, and a key groove may be formed in the inner peripheral surface of the feed nut 31 so as to correspond to the key.

  In the above-described embodiment, the feed mechanism is exemplified as a feed screw mechanism configured by combining the male screw 33 of the feed nut 31 with the female screw 42 of the tubular member 41. However, the feed mechanism is configured as follows. Also good. For example, one or a plurality of short columnar guide portions may protrude from the outer peripheral surface of the feed nut 31, and a spiral guide groove that guides the guide portion may be formed on the inner peripheral surface of the cylindrical member 41. .

  In the above-described embodiment, the configuration in which the steering device 100 is mounted on a four-wheeled vehicle has been exemplified. But you can. For example, when mounted on the ATV, the rack shaft 131 is not provided, a steering plate that rotates around the steering shaft 21 is fixed to the lower end of the steering shaft 21, and the steering plate is connected to the steering wheel via a tie rod. It may be configured.

  In the above-described embodiment, the configuration in which the steering device 100 is the SBW system has been exemplified. However, for example, the steering device 100 may be a normal EPS (Electronic Power Steering). If comprised in this way, the impact at the time of the left rack end 135A colliding with the left stopper 136A can be reduced, for example.

11 Steering wheel (operation member)
21 Steering shaft 25 Shaft spline (Rotation-slide mechanism)
30 Stopper mechanism 31 Feed nut (annular member)
32 hole spline (rotation-slide mechanism)
33 Male thread (feed mechanism)
41 Cylindrical member 42 Female thread (feed mechanism)
43A Upper stopper (Regulator)
43B Lower stopper (regulating member)
100 Steering device

Claims (3)

A steering shaft that rotates integrally with an operating member operated by the driver;
An annular member disposed around the steering shaft;
A rotation-sliding mechanism for rotating the steering shaft and the annular member integrally in the circumferential direction, and enabling the annular member to slide in the axial direction with respect to the steering shaft;
A cylindrical member that is disposed so as to surround the annular member and is in a non-rotating state;
A feed mechanism for feeding the annular member in the axial direction with respect to the steering shaft by the rotational movement of the annular member relative to the tubular member;
A regulating member that is arranged on both sides of the annular member in the axial direction, and that the annular member abuts to regulate sliding movement of the annular member in the axial direction;
A steering apparatus comprising: The steering apparatus according to claim 1, wherein the rotation-slide mechanism is configured by spline coupling the steering shaft and the annular member. The feed mechanism is a feed screw mechanism configured by combining a male screw formed on an outer peripheral surface of the annular member with a female screw formed on an inner peripheral surface of the cylindrical member. The steering device according to claim 1 or 2.

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