JP2007131058A - Steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering device capable of giving the same steering feeling as the conventional one mechanically connecting a steering wheel and a steered wheel to a driver without using electric power. <P>SOLUTION: This steering device is furnished with an elastic member 76 to press cam followers 75, 75 directly operated by following cams 74, 74 rotating in accordance with the rotation of the steering wheel 20 on a cam curved surface 74a, the cam curved surface 74a is curved left and right in the circumferential direction so that a distance between an axis of a rotation shaft 72A and a contact surface to the cam follower 75 becomes longer as a steering angle is increased, and inclination of each part in this circumferential direction is acutely and moderately formed by each of the parts in the axial direction of the cam 74 at the same steering angle. Further, a cam follower position adjusting means 77 to move the cam follower 75 to acutely inclined portions 74b<SB>1</SB>, 74c<SB>1</SB>of the cam curved surface 74a in accordance with the turning of the steering wheel 20 and to move the cam follower 75 to moderately inclined portions 74b<SB>2</SB>, 74c<SB>2</SB>of the cam curved surface 74a in accordance with its turn-back is provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a steer-by-wire type steering apparatus in which there is no mechanical connection between a steering wheel and a steered wheel, and relates to a steering apparatus that can eliminate a driver's uncomfortable feeling when operating the steering wheel.

  2. Description of the Related Art Conventionally, in many steering devices mounted on a vehicle, a steering wheel and a steering wheel are mechanically connected. For example, in this type of steering device, a steering shaft that holds a steering wheel is connected to a steered shaft via a rack and pinion mechanism, and a steered wheel is connected to each tie rod that is connected to both ends of the steered shaft. It adopts a configuration to do. For this reason, in this conventional steering device, the steering torque when the driver steers the steering wheel is directly transmitted to the steered wheels via the steering shaft, the rack and pinion mechanism, and the like. Wheel steering is performed.

  Here, in such a steering device, the steering direction of the driver is determined by the transmission part of the steering torque such as the rack and pinion mechanism, the frictional force in the steering wheel, and the self-aligning torque in the steering wheel at the time of turning. A reverse reaction force (hereinafter referred to as “steering reaction force”) is generated and transmitted to the steering wheel. On the other hand, in this steering device, an inertia according to the steering direction is generated in the steering torque transmission part, the steering wheel, the steering wheel itself, and the like with the steering of the driver, and each of the inertias corresponds to the steering direction. The inertial force in the same direction is transmitted to the steering wheel. For this reason, once the driver starts to steer the steering wheel, the steering reaction force is reduced by the inertial force, so that the steering wheel can be steered without applying excessive steering torque to the steering wheel. However, since there is no inertial force at the start of steering, the driver must steer the steering wheel with a large steering torque.

  Therefore, this steering device is provided with a steering torque assisting means for assisting the steering torque by the driver in order to reduce the burden on the driver. For example, as the steering torque assisting means, there is one utilizing a hydraulic pressure of a pump that is driven in conjunction with rotation of a crankshaft of an internal combustion engine (so-called hydraulic power steering). This type of steering torque assisting means operates the steering shaft, the rack and pinion mechanism, etc. using the hydraulic pressure generated by the pump, thereby reducing the steering torque of the driver.

  However, in this type of steering torque assisting means, since the pump is always driven, a pumping loss is always generated in the internal combustion engine, and the fuel consumption is deteriorated.

  Therefore, a steering torque assisting means has been developed that operates the steering shaft or the like with the driving force of the electric motor instead of the hydraulic pressure, thereby reducing the pumping loss of the internal combustion engine and improving the fuel consumption. For example, as a steering apparatus provided with such steering torque assisting means, a so-called electric motor that drives a steering shaft connected to a steering wheel or a rack connected to the tip of the steering shaft by an electric motor according to the steering angle of the steering wheel. There is power steering.

  Further, as a further development of this electric power steering, by turning the mechanical connection between the steering wheel and the steered wheels, the turning angle imparting means provided with the electric motor and the driving force transmission mechanism for transmitting the driving force thereof. There is a so-called steer-by-wire type steering device that steers a steered wheel to a steered angle corresponding to the steered angle of the steering wheel.

  Here, in the steer-by-wire type steering apparatus exemplified as the latter, since the steering wheel and the steering wheel are not mechanically connected, the conventional steering wheel and the steering wheel are mechanically connected. The steering reaction force expected by the driver to be obtained in the same manner as the steering device is not transmitted to the steering wheel. Strictly speaking, in this steer-by-wire type steering device, the steering reaction force caused by the friction force on the steering wheel side (frictional force accompanying the sliding of the steering shaft, etc.) is transmitted to the steering wheel. The steering reaction force due to the frictional force (frictional force in the turning angle applying means, etc.) and the self-aligning torque in the steering wheel is not transmitted to the steering wheel side. For this reason, the steering reaction force is greatly reduced as compared with the conventional steering device (hydraulic power steering or electric power steering) in which the steering wheel and the steering wheel are mechanically connected. When changing from a vehicle equipped with a steering device to a vehicle equipped with a steer-by-wire type steering device, it feels strange that the steering reaction force during steering wheel steering is small. That is, in this steer-by-wire type steering device, it is impossible to transmit a steering reaction force having a magnitude in line with the actual situation at the time of steering wheel equivalent to the conventional steering device to the driver. Compared to this, the steering feeling is worsened.

  In view of this, the steer-by-wire steering device includes a steering reaction force generating means that virtually applies a steering reaction force to the steering wheel to compensate for the above-described decrease. For example, as this steering reaction force generating means, an electric motor is driven based on the movement of the steering wheel (steering angle, steering torque, etc.), and the torque in the direction opposite to the steering direction of the steering wheel is applied via the gear to the steering shaft. Some of them generate steering reaction force by transmitting to

  In Patent Document 1 below, a cam that interlocks with the rotation of the steering wheel and a cam that is in contact with the origin of the cam when the vehicle goes straight, and changes linearly according to the cam surface shape change that changes with the rotation of the steering wheel. A cam follower, an elastic member (compression coil spring) that is elastically deformed as the cam follower linearly moves, and an electric motor that moves the cam follower in the linear motion direction to change the elastic force of the elastic member. A steering reaction force generating means is disclosed. The steering reaction force generating means applies a steering reaction force to the steering wheel via a cam pressed by the elastic force of the elastic member, and changes the position of the cam follower with an electric motor. It is something to change.

JP 2004-314735 A

  However, in the steer-by-wire type steering device disclosed in Patent Document 1, the steering reaction force similar to that of the conventional steering device in which the steering wheel and the steering wheel are mechanically connected is generated, and good steering is achieved. In order to obtain a feeling, the electric motor is always driven in accordance with the steering of the steering wheel, so that the discharge amount of the storage battery increases every time the steering wheel is steered.

  In the steering device disclosed in Patent Document 1, since the heart-shaped cam is used, the cam follower can continue to move on the cam curved surface, and the steering wheel has the maximum turning angle (steering limit). The steering wheel rotation end (hereinafter referred to as the “steering end”) at the time of reaching the position could not be felt by the driver. For this reason, in such a steering apparatus, the driver feels uncomfortable and cannot give the driver a good steering feeling.

  Therefore, the present invention improves the inconvenience of the conventional example, and is similar to the conventional steering device in which the steering wheel and the steering wheel are mechanically connected without using the electric force of the electric motor or the like. It is an object of the present invention to provide a steering device that can give a feeling of steering to a driver.

  In order to achieve the above object, in the invention of claim 1, a cam curved surface is formed on the peripheral wall surface, and the cam rotates in the circumferential direction as the steering wheel rotates, and a cam curved surface of the cam abuts. In addition, in a steering apparatus including a cam follower that linearly follows the rotation of the cam and an elastic member that presses the cam follower against the cam curved surface, the steering angle of the steering wheel from the steering center of the steering wheel is adjusted to the left and right respectively. As the distance increases, the distance between the axis of the rotation axis of the cam and the contact surface of the cam follower becomes longer in the circumferential direction, and each of the left and right curved shapes in the circumferential direction is curved. Gradients are formed in each part of the cam in the axial direction at the same steering angle, and the cam follower is adjusted according to the incision of the steering wheel. The cam follower position is adjusted to move the cam follower toward the steep slope part of the cam curved surface in the axial direction of the cam, while moving the cam follower toward the gentle slope part of the cam curved surface toward the cam slope in response to switching back of the steering wheel. Means are provided.

  In this steering apparatus, the cam follower moves to a steep portion of the cam curved surface according to the rotation of the steering wheel when the steering wheel is cut, and according to the rotation of the steering wheel when the steering wheel is turned back. Move to the gentle slope part of the cam surface. As a result, when the steering wheel is turned, the elastic force of the elastic member becomes larger than when the steering wheel is turned back, and a large steering reaction force can be generated, and the characteristics of the steering reaction force change between the turning time and the turning back time. Can be made. For this reason, according to the steering device of the first aspect, the situation is similar to that of the conventional steering device in which the steering wheel and the steering wheel are mechanically connected depending on whether the steering wheel is cut or turned back. The hysteresis characteristic of the steering reaction force can be provided without using an electric force such as an electric motor.

  In order to achieve the above object, according to the second aspect of the present invention, a cam curved surface is formed on the peripheral wall surface, and the cam rotates in the circumferential direction with the rotation of the steering wheel, and the cam curved surface of the cam. In a steering apparatus comprising a cam follower that is in direct contact with and follows the rotation of the cam and an elastic member that presses the cam follower against the cam curved surface, the cam curved surface is adjusted to obtain a steering angle from the steering center of the steering wheel. The friction between the cam follower and the cam curved surface is formed by curving the left and right in the circumferential direction so that the distance between the axis of the rotating shaft of the cam and the contact surface of the cam follower becomes longer as the left and right are increased. The coefficient is configured to be high.

  In the steering apparatus according to claim 2, in addition to the steering reaction force generated by the torque component accompanying the elastic force of the elastic member when the steering wheel is cut, the torque caused by the frictional force between the cam follower and the cam curved surface Since the steering reaction force is generated depending on the components, a large steering reaction force is transmitted to the steering wheel. On the other hand, the elastic force of the elastic member and the steering reaction force due to the frictional force between the cam follower and the cam curved surface are generated even when the steering wheel is switched back. At the time of switching back, the cam follower moves to the valley side of the cam curved surface. As a result, the frictional force decreases, and the steering reaction force becomes smaller than that at the time of cutting. For this reason, according to the steering device of the second aspect, the characteristics of the steering reaction force can be changed between when the steering wheel is turned and when the steering wheel is turned back by the coefficient of friction between the cam follower and the cam curved surface. It is possible to provide a hysteresis characteristic of a steering reaction force in accordance with the same situation as a conventional steering device in which a wheel and a steering wheel are mechanically connected without using an electric force such as an electric motor.

  In order to achieve the above object, according to a third aspect of the present invention, in the steering apparatus according to the first or second aspect, a protruding portion is provided at each end portion in the circumferential direction on each of the left and right sides of the cam curved surface.

  According to the steering device of the third aspect, the cam follower comes into contact with any one of the projecting portions according to the steering direction when the steering wheel is cut, thereby locking the cam. As a result, the steering wheel cannot be cut in the same direction. For this reason, the driver can feel the steering end when the steering wheel reaches the turning limit only with such a mechanical configuration, and the steering wheel and the steering wheel are mechanically connected to each other. A steering feeling similar to that of the steering device can be obtained.

  The steering apparatus according to the present invention provides the driver with a good steering feeling without any discomfort similar to the conventional steering apparatus in which the steering wheel and the steering wheel are mechanically coupled only by the mechanical configuration described above. be able to. In addition, since this steering device creates a good steering feeling with a simple configuration that does not use electric power such as an electric motor, it also contributes to a reduction in power consumption and an improvement in reliability.

  Hereinafter, embodiments of a steering apparatus according to the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments.

  A steering apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

  Reference numeral 10 in FIG. 1 shows the overall configuration of the steering apparatus according to the first embodiment. In the first embodiment, a mechanical device is interposed between the steering wheel 20 and the left and right steering wheels 100L and 100R of the vehicle. This represents a so-called steer-by-wire system with no connection.

  The steer-by-wire steering device 10 according to the first embodiment includes a steering wheel 20, a rotating shaft (hereinafter referred to as a "steering shaft") 21 connected to the steering wheel 20, and a steering wheel 20, as shown in FIG. A steering angle sensor 22 for detecting the steering angle of the steering wheel 20, a control means 30 to which a detection signal of the steering angle sensor 22 is input, and a steering force for each of the steered wheels 100L and 100R are generated to generate each Steering angle imparting means 40 for giving a steered angle according to a command from the control means 30 to the steered wheels 100L and 100R, and steered wheels connected to both ends by transmitting the steering force of the steered angle imparting means 40 And a shaft 50 for turning 100L and 100R.

  First, as the steering angle sensor 22, for example, a sensor that is disposed on the steering shaft 21 or in the vicinity of the outer peripheral surface of the steering shaft 21 and detects the rotational movement amount or the rotational angle of the steering shaft 21 is used. A detection signal of the steering angle sensor 22 is transmitted to the control unit 30, and the steering angle of the steering wheel 20 is calculated by the control unit 30.

  In addition to the detection signal from the steering angle sensor 22, the control means 30 uses a vehicle speed signal from the vehicle speed sensor 61, a yaw angle signal from the yaw rate sensor 62, a lateral acceleration signal from the lateral acceleration sensor 63, and the like. The optimum turning angles of the steering wheels 100L, 100R are obtained and transmitted to the turning angle providing means 40. The control means 30 may be dedicated to the steering device 10 or may be provided as a function of an electronic control unit (ECU) that performs integrated control of the vehicle and combustion control of the internal combustion engine. In the first embodiment, the latter case will be exemplified.

  Further, as the turning angle imparting means 40 of the first embodiment, the electric motor 41 is driven based on the command value of the turning angle from the control means 30, and the shaft 50 is linearly moved in the left-right direction of the vehicle by the driving force. What steers the steered wheels 100L and 100R is used. That is, in the turning angle providing means 40, the electric motor 41 is used as a turning force generating means for generating a turning force for the respective steered wheels 100L and 100R. For example, the electric motor 41 according to the first embodiment includes a tubular rotor 41a, a stator 41b that covers the outer periphery of the rotor 41a, and the like, and a shaft 50 is inserted into the rotor 41a.

  Here, the turning angle imparting means 40 of the first embodiment is provided with a turning force transmission mechanism 42 that transmits the turning force of the electric motor 41 to the shaft 50. As shown in FIG. 2, the turning force transmission mechanism 42 is formed on the inner peripheral surface of the rotor 41a of the electric motor 41 or on the outer peripheral surface of the shaft 50 and the ball screw nut 42a attached to the rotor 41a. In addition, a ball screw mechanism including a spiral ball screw portion 42b and a plurality of balls 42c disposed between the ball screw nut 42a and the ball screw portion 42b is used. In this type of steering force transmission mechanism 42, the ball screw nut 42a rotates in the circumferential direction as the electric motor 41 is driven (that is, the rotor 41a rotates), and the shaft 50 is moved to the left of the vehicle according to the rotation direction. Alternatively, the steering wheels 100L and 100R connected to both ends of the shaft 50 are steered by direct movement in the right direction.

  Further, the turning angle providing means 40 is provided with a turning angle sensor 43 that detects the turning angles of the steered wheels 100L and 100R. For example, the turning angle sensor 43 is disposed near the outer peripheral surface of the shaft 50 as shown in FIG. 2, and detects the rotational angle of the shaft 50 or the amount of movement in the axial direction (the left-right direction of the vehicle). Use. In the case of this type of turning angle sensor 43, the control means 30 that has received the detection signal calculates the turning angle based on the rotation angle or the movement amount.

  By the way, in such a steer-by-wire type steering apparatus 10, the steering wheels 100L, 100R and the steering wheel 20 are not mechanically connected, so that the steering reaction force transmitted to the steering wheel 20 is steered from the steering wheel. This is smaller than the conventional steering device that mechanically connects the wheels. For this reason, when a driver who is familiar with the conventional steering device uses the steer-by-wire type steering device 10, the driver feels uncomfortable with the small steering reaction force and feels the deterioration of the steering feeling.

  Therefore, in the first embodiment, the steering reaction force generating means 70 that virtually applies the steering reaction force to the steering wheel 20 is provided. The steering reaction force generating means 70 is provided on the steering shaft 21 and forcibly generates a torque that resists the steering torque applied by the driver to the steering wheel 20 and uses this as a steering reaction force for the driver. It is transmitted via the steering wheel 20. The steering reaction force generating means 70 will be described in detail below.

  The steering reaction force generating means 70 of the first embodiment is disposed at the other end of the steering shaft 21 to which the steering wheel 20 is connected at one end.

  First, as shown in FIGS. 3 to 5, the steering reaction force generating means 70 is meshed with a first spur gear 71A having a rotation center fixed to the other end of the steering shaft 21 and the first spur gear 71A. Second and third spur gears 71B and 71C are provided.

  In the second and third spur gears 71B and 71C, the axes of the rotation shafts 72A and 72B fitted to the respective rotation centers are in the same plane together with the axis of the rotation shaft (the steering shaft 21) of the first spur gear 71A. It arrange | positions so that it may be located, and it fixes so that it can rotate with respect to the housing | casing 73 shown in FIG.4 and FIG.5 via each rotating shaft 72A, 72B.

  In addition, the second and third spur gears 71B and 71C of the first embodiment are each formed as a large gear having more teeth than the first spur gear 71A. For this reason, when the first spur gear 71A rotates (for example, when the driver steers the steering wheel 20), the second spur gear 71B and the third spur gear 71C decelerate with respect to the rotational speed. Can be rotated. For example, the gear ratios between the first spur gear 71A and the second spur gear 71B and between the first spur gear 71A and the third spur gear 71C are the cams 74 described below with respect to the steering angle of the steering wheel 20, respectively. Considering the amount of movement of the cam 74 in the axial direction of the cam follower 75 described below with respect to the rotation angle of the steering wheel 20 and the steering angle of the steering wheel 20 and the like, an optimal one corresponding to the vehicle or the like is appropriately set based on the results of experiments and simulations.

  Here, a cam 74 shown in FIG. 3 having a peripheral wall surface as a cam curved surface 74a is integrally disposed on one end surface of the second spur gear 71B, and the steering reaction force generating means 70 of the first embodiment is provided. Is in direct contact with the cam 74 and the cam curved surface 74a of the cam 74, and moves linearly in the axial direction of the rod-shaped cam follower main body 75a with an operation amount corresponding to the shape change of the cam curved surface 74a when the cam 74 rotates. The steering wheel 20 is moved to the steering wheel 20 by using a cam follower 75 that rotates and a roller 75b at the tip of the cam follower 75 against the cam curved surface 74a of the cam 74 and an elastic member 76 such as a string-wound spring that expands and contracts as the cam follower 75 moves linearly. The steering reaction force to be transmitted is generated, and the magnitude is adjusted. 3 to 5 show a state of the cam 74 and the like when the steering wheel 20 is in a neutral position (hereinafter referred to as “steering center”).

  In the steering reaction force generating means 70, the cam 74 has a rotation shaft 72A of the second spur gear 71B as an axis in the cam contour, and the cam 74 is integrated with the second spur gear 71B. By rotating, the cam follower 75 is linearly moved in the axial direction of the cam follower main body 75a with an operation direction and an operation amount corresponding to the shape change of the cam curved surface 74a. At this time, if the cam follower 75 operates in a direction in which the elastic member 76 is compressed, the elastic force of the elastic member 76 increases in accordance with the operation amount, and the cam follower 75 extends the elastic member 76. If it works, it becomes smaller according to the amount of operation.

  In the steering reaction force generating means 70, the roller 75b of the cam follower 75 is pressed against the cam curved surface 74a with a pressing force corresponding to the elastic force of the elastic member 76, and the rotation direction of the cam 74 according to the pressing force. Torque in the opposite direction acts on the cam 74. For this reason, the steering reaction force generating means 70 transmits the torque to the first spur gear 71A and the steering shaft 21 via the second spur gear 71B, and the torque applied to the steering shaft 21 (hereinafter referred to as “steering reaction force”). A force corresponding to “force torque”) is transmitted to the steering wheel 20 as a steering reaction force.

  On the other hand, since the magnitude of the elastic force of the elastic member 76 changes according to the shape change of the cam curved surface 74a when the cam 74 rotates, the pressing force of the cam follower 75 corresponding to the change acts on the cam 74. The steering reaction torque corresponding to the pressing force is applied to the steering shaft 21. For this reason, in this steering reaction force generating means 70, a steering reaction force corresponding to the rotation angle of the cam 74 (that is, corresponding to the steering angle of the steering wheel 20) is transmitted to the steering wheel 20 via the steering shaft 21. The

  Here, the steering reaction force generated by the steering reaction force generating means 70 is the same as long as the steering angle from the steering center is the same regardless of whether the steering wheel 20 is steered in the left or right direction from the steering center. It is preferable to generate a large size from the viewpoint of good steering feeling. From a similar viewpoint, it is preferable that the steering reaction force increases as the steering angle increases until the steering angle of the steering wheel 20 from the steering center reaches a predetermined angle.

  On the other hand, when turning the vehicle, the driver cuts the steering wheel 20 at the corner entrance and then turns it back at the corner exit. However, if the steering angle from the steering center at the time of the turning and the turning back is the same, If the generating means 70 generates a steering reaction force of the same magnitude, the difference between the steering feeling at the time of cutting and the steering feeling at the time of switching back will cause a sense of incongruity. This is because, in a conventional steering device in which a steering wheel and a steering wheel are mechanically connected, a steering reaction force is large due to self-aligning torque or the like when the steering wheel is cut. This is because the steering reaction force is reduced due to the inertia of the steering wheel or the like when returning, and it is necessary to generate a steering reaction force having a magnitude different between when the steering wheel 20 is cut and when the steering wheel 20 is turned back in light of the actual situation. .

  Therefore, the cam 74 of the first embodiment forms a three-dimensional curved surface capable of producing the steering reaction force hysteresis characteristics shown in FIG. 6 that are different between when the steering wheel 20 is cut and when the steering wheel 20 is turned back. The three-dimensional curved surface is used as a cam curved surface 74a on which the roller 75b of the cam follower 75 rolls. In FIG. 6, the steering angle from the steering center when the steering wheel 20 is steered to the right is positive, and the steering reaction torque applied to the steering shaft 21 at that time is positive.

  Specifically, as shown in FIG. 3, the three-dimensional curved surface that forms the cam curved surface 74a is such that the distance from the axis of the rotating shaft 72A to the contact surface with the roller 75b of the cam follower 75 is such that the steering wheel 20 is positioned at the steering center. When the steering wheel 20 is shortest, the left and right sides of the steering wheel 20 are curved to the left and right in the circumferential direction so as to gradually and evenly become longer as the steering angle of the steering wheel 20 from the steering center to the left and right is increased. That is, the cam curved surface 74a of the first embodiment is constituted by two curved convex surfaces (hereinafter referred to as “first and second curved convex surfaces”) 74b and 74c shown in FIGS. In the first embodiment, when the steering wheel 20 is at the steering center, the roller 75b is positioned at the boundary point 74d between the first and second curved convex surfaces 74b and 74c, while the steering wheel 20 is moved to the left. When steered, the roller 75b rolls on the first curved convex surface 74b, and when steered to the right, the roller 75b rolls on the second curved convex surface 74c.

  Further, in the first embodiment, the first and second curved convex surfaces 74b and 74c described above are set so that the steering reaction force at the time of turning back becomes smaller than the steering reaction force at the time of turning of the steering wheel 20. Form. For example, if the steering angle from the steering center (in other words, the rotation angle of the cam 74) is the same, the distance from the axis of the rotating shaft 72A to the contact surface of the cam curved surface 74a with the roller 75b is the cam curved surface 74a. The steeper in the circumferential direction, the longer the gradient, and the greater the steering reaction force generated there. For this reason, the first and second curved convex surfaces 74b and 74c of the first embodiment give the slopes of the respective portions in the respective circumferential directions at the respective portions in the axial direction of the cam 74 at the same steering angle. That is, the first and second curved convex surfaces 74b and 74c of the first embodiment have a plurality of curves with different gradient changes in the circumferential direction (hereinafter referred to as “steering reaction force characteristic curves”) in the axial direction of the cam 74. To form a three-dimensional curved surface.

These first and second curved convex surfaces 74b and 74c are provided with steeply inclined portions 74b ₁ and 74c ₁ and gently inclined portions 74b ₂ and 74c ₂ as shown in FIGS. 4 and 5, and a roller 75b of the cam follower 75 is provided. Are moved to the steep slope parts 74b ₁ and 74c ₁ when the steering wheel 20 is cut, and moved to the gentle slope parts 74b ₂ and 74c ₂ when the steering wheel 20 is turned back. The steep slope portion 74b ₁ and the gentle slope portion 74b _{2 of} the first curved convex surface 74b and the steep slope portion 74c ₁ and the gentle slope portion 74c ₂ of the second curved convex surface 74c are gradually increased as shown in FIGS. 4 and 5, respectively. That is, it is changed smoothly in the axial direction of the cam 74.

In the cam 74 of the first embodiment, the second spur gear 71B side (i.e., the second spur gear 71B and the bonding surface side of the cam 74) and low-gradient portion 74b ₂ of the first curved convex surface 74b on the second curved convex surface 74c The steep slope portion 74c ₁ is arranged. For this reason, the cam follower 75 and the elastic member 76 move in a direction away from the second spur gear 71B when the steering wheel 20 is cut to the left, and move in a direction approaching the second spur gear 71B when turning back from there. I have to let it. On the other hand, when the steering wheel 20 is turned to the right, the cam follower 75 and the elastic member 76 are moved in a direction approaching the second spur gear 71B, and when returning from there, the cam follower 75 is moved away from the second spur gear 71B. And the elastic member 76 must be moved. That is, in order to generate a steering reaction force having different magnitudes at the same position (the same steering angle from the steering center) when the steering wheel 20 is cut and turned back, the shape of the cam curved surface 74a described above is used. In addition, the cam follower 75 and the elastic member 76 need to be appropriately reciprocated in the axial direction of the cam 74.

  Therefore, in the first embodiment, the cam follower 75 and the elastic member 76 are configured as follows, and these are moved in the axial direction of the cam 74 as the steering wheel 20 is cut or turned back. Cam follower position adjusting means 77 is provided that adjusts the steering reaction force to a magnitude corresponding to the cut or return, thereby changing the characteristic of the steering reaction force.

  The cam follower 75 according to the first embodiment includes the above-described rod-shaped cam follower main body 75a and a roller 75b pivotally supported on one end side of the cam follower main body 75a, and an elastic member (string winding) is provided on the other end of the cam follower main body 75a. A spring receiver 75c for holding one end of the (spring) 76 is provided. The cam follower main body 75a of the cam follower 75 is arranged so that its axis is orthogonal to the axis of the rotating shaft 72A of the cam 74 and is located in the same plane having the axis of the steering shaft 21 and the rotating shafts 72A and 72B. To do.

  Here, in the first embodiment, since the cam follower 75 moves in the circumferential direction and the axial direction of the cam 74 on the cam curved surface 74a formed of the above-described three-dimensional curved surface, the roller 75b smoothly moves on the cam curved surface during the movement. It is configured to be able to roll on 74a. For example, in the first embodiment, a caster mechanism 75d is interposed between the cam follower main body 75a and the roller 75b, and the roller 75b rotates about the axis of the cam follower main body 75a via the caster shaft 75e. Constitute. Thereby, when the cam follower 75 moves in the circumferential direction and the axial direction of the cam 74, the roller 75b can be smoothly rolled in accordance with the shape of the cam curved surface 74a.

  The steering reaction force generating means 70 of the first embodiment is provided with a cam follower guide portion 75f that holds the other end of the elastic member 76 and guides the spring receiver 75c of the cam follower 75 in the axial direction of the cam follower main body 75a. Yes. The cam follower guide portion 75f has a cylindrical shape with one end closed. The cam follower guide portion 75f is inserted through the spring receiver 75c and the elastic member 76 from the opening end to hold one end of the elastic member 76. The other end of the elastic member 76 is held by the wall surface.

  In the first embodiment, the cam follower position adjusting means 77 is provided in the cam follower guide portion 75f, and the cam follower 75 and the elastic member 76 are moved by reciprocating the cam follower guide portion 75f in the axial direction of the cam 74. The cam 74 is reciprocated in the axial direction in accordance with the turning or turning back of the steering wheel 20.

  For example, as the cam follower position adjusting means 77 of the first embodiment, a so-called rack and pinion mechanism including a rack gear 77a and a pinion gear 77b shown in FIGS. 3 to 5 is used. The pinion gear 77b is attached to the rotation shaft 72B of the third spur gear 71C described above. As the rotation shaft 72B rotates, the rack gear 77a is moved in the axial direction of the rotation shaft 72B (that is, the axial direction of the cam 74). ). On the other hand, a cam follower guide portion 75f is integrally attached to the rack gear 77a. Therefore, the cam follower guide portion 75f adjusts the cam follower position in the axial direction of the cam 74 in accordance with the rotation direction of the third spur gear 71C. Move via means 77.

Here, the cam follower position adjusting means 77 is provided with a rack gear guide portion 77 c for guiding the rack gear 77 a described above in the axial direction of the cam 74. The rack gear guide portion 77c has a cylindrical shape whose both ends are closed, and a rack gear 77a is provided on the inside thereof. Therefore, on the wall surface of the rack gear guide portion 77c, a cam follower guide portion 75f fixed to the rack gear 77a protrudes outward, and the cam follower guide portion 75f is reciprocated without being locked by the wall surface. 77c ₁ is formed. In addition, elastic members 77d and 77e such as string-wound springs are disposed inside the rack gear guide portion 77c and at both ends of the rack gear 77a in the reciprocating direction.

  In the steering reaction force generating means 70 described above, the cam follower position adjusting means 77 causes the roller 75b and the elastic member 76 of the cam follower 75 to reciprocate in the axial direction of the cam 74, and responds when the steering wheel 20 is cut or turned back. A large amount of steering reaction force is generated. At this time, in the steering reaction force generating means 70, the roller 75b moves on the cam curved surface 74a in the circumferential direction of the cam 74 and also moves in the axial direction of the cam 74, and when the steering wheel 20 is cut or turned back. Transition is made on various steering reaction force characteristic curves on the cam curved surface 74a corresponding to the time. For this reason, when the steering wheel 20 is cut, the roller 75b moves on the cam curved surface 74a obliquely (circumferential direction and axial direction of the cam 74), and gradually shifts on various steering reaction force characteristic curves. Reaction force increases.

  However, the steering wheel 20 is cut as it is, and when the steering angle from the steering center reaches a certain angle, the rotation of the pinion gear 77b is stopped by the resilience of the elastic member 76 that has been increased. The wheel 20 cannot be cut.

  That is, the elastic force of the elastic member 76 causes the cam follower 75 to generate a pressing force against the cam curved surface 74a for generating a steering reaction force, and between the rack gear 77a and the pinion gear 77b via the rack gear 77a. Increase sliding resistance and frictional resistance. The elastic member 76 increases or decreases the elastic force depending on the compression amount corresponding to the change in the shape of the cam curved surface 74a, and increases the steering reaction force as the compression amount increases. Since the sliding resistance and frictional resistance between the rack gear 77a and the pinion gear 77b are also increased according to the amount of compression, the rotation of the pinion gear 77b is stopped. This stops the operation of the rack gear 77a, and not only the movement of the roller 75b and the elastic member 76 in the axial direction of the cam 74 but also the rotation of the first and second spur gears 71A and 71B are stopped. As a result, the steering wheel 20 cannot be cut any further.

  Therefore, in the first embodiment, a torque limiter 78 is provided on the rotation shaft 72B of the third spur gear 71C. The torque limiter 78 integrally rotates the third spur gear 71C and the pinion gear 77b until an excessive torque is applied to the rotation shaft 72B in the direction opposite to the rotation direction of the rotation shaft 72B. When such excessive torque in the reverse rotation direction is applied to the rotation shaft 72B, the engagement between the third spur gear 71C and the pinion gear 77b can be released to rotate each independently independently. It is.

  For example, when the torque limiter 78 is operated (when the engagement between the third spur gear 71C and the pinion gear 77b is released), excessive torque in the reverse rotation direction applied to the rotation shaft 72B is caused by the elastic member 76. It is set to a value smaller than the torque in the reverse rotation direction applied to the rotating shaft 72B when the rotation of the pinion gear 77b is stopped by the elastic force (hereinafter referred to as “torque limiter operating torque”). As a result, when the torque limiter operating torque in the direction opposite to the rotation direction of the rotation shaft 72B is applied to the rotation shaft 72B, the third spur gear 71C continues to rotate while the pinion gear 77b stops rotating. The steering wheel 20 can be further steered, and the cam follower 75 and the elastic member 76 can be stopped at such positions.

  By the way, when the steering wheel 20 is further cut even after the torque limiter 78 is actuated, the respective steered wheels 100L and 100R reach the maximum turning angle (that is, the turning limit). However, since the steering device 10 of the first embodiment has no mechanical connection between the steering wheel 20 and the steering wheels 100L and 100R as described above, even if the steering wheels 100L and 100R reach the turning limit. The steering wheel 20 continues to turn, which is not preferable.

  Therefore, the steering reaction force generating means 70 of the first embodiment is provided with a mechanism for transmitting the steering end when the steered wheels 100L and 100R reach the turning limit to the driver. For example, in the first embodiment, the protrusions 74e and 74f shown in FIG. 3 are provided at the respective circumferential end portions on the left and right sides of the cam curved surface 74a, and the respective left and right turning limits are reached. The protrusions 74e and 74f are locked by the roller 75b of the cam follower 75. As a result, the rotation of the cam 74 is stopped and the rotation of the first and third spur gears 71A, 71C is stopped, so that the steering wheel 20 cannot be further cut, and the left and right steering ends are provided to the driver. Can be recognized.

  The operation of the steering device 10 configured as described above will be described below. In the following, a case where the vehicle is turned to the right will be described as an example.

  First, when the driver cuts the steering wheel 20 to the right from the steering center, the first spur gear 71A of the steering reaction force generating means 70 is turned rightward (counterclockwise on the paper surface of FIG. 3) via the steering shaft 21. Start spinning. Accordingly, the second and third spur gears 71B and 71C rotate in the left direction (clockwise on the paper surface of FIG. 3), and the cam 74 and the pinion gear 77b engaged therewith are also interlocked. Rotate in the same direction.

Accordingly, the cam follower 75 linearly moves in the axial direction of the cam follower 75 so as to follow the cam 74, and in conjunction with the movement of the rack gear 77a accompanying the rotation of the pinion gear 77b, together with the elastic member 76, the axial direction of the cam 74 ( It moves to the side of the joint surface with the second spur gear 71B indicated by the arrow A in FIG. At this time, in the cam follower 75, the roller 75b rolls on the cam curved surface 74a from the boundary point 74d between the first and second curved convex surfaces 74b and 74c toward the steeply inclined portion 74c ₁ of the second curved convex surface 74c. Then, along with this rolling, the elastic member 76 is gradually compressed to increase the resilience.

  As a result, in this steering reaction force generating means 70, a pressing force corresponding to the elastic force of the elastic member 76 is applied to the cam curved surface 74 a via the cam follower 75, and the torque resists the rotational torque of the cam 74 by the pressing force. Is generated in the cam 74, torque against the rotational torque is transmitted to the steering shaft 21 as steering reaction force torque, and a steering reaction force corresponding to the steering reaction force torque is transmitted to the steering wheel 20.

  Therefore, in this steering reaction force generating means 70, the elastic force of the elastic member 76 is increased as the steering wheel 20 is cut, and the steering reaction force transmitted to the steering wheel 20 is gradually increased.

  Here, a case where the driver turns back the steering wheel 20 from the position after the cutting will be described.

  In such a case, the driver steers the steering wheel 20 to the left. Accordingly, since the first spur gear 71A starts to rotate leftward, the second and third spur gears 71B and 71C, the cam 74 and the pinion gear 77b engaged therewith rotate rightward.

As a result, in the steering reaction force generating means 70, the cam follower 75 and the elastic member 76 move together with the rack gear 77a in the opposite axial direction (arrow B in FIG. 5), and the roller 75b of the cam follower 75 is applied in the axial direction. to rolling toward the low-gradient portion 74c ₂ of the second curved convex surface 74c of the cam curve 74a according to the rotation of the moving cam 74. For this reason, in this steering reaction force generating means 70, the elastic member 76 expands as the steering wheel 20 is turned back, and its elastic force decreases, so that the steering reaction force transmitted to the steering wheel 20 is reduced. The force gradually decreases.

Here, at the time of turning back, the rack gear 77a is pushed back in the direction of arrow B by the elastic force of the elastic member 77d of the cam follower position adjusting means 77 compressed at the time of turning of the steering wheel 20, so that the roller 75b of the cam follower 75 is turned on. The vehicle is steered on various steering reaction force characteristic curves toward the gentle gradient portion 74c _{2 through} different paths. For this reason, as shown in FIG. 6, the steering reaction force generating means 70 generates a steering reaction force smaller than that at the time of the incision even when the steering angle from the steering center is the same.

  After that, when the steering wheel 20 is turned back to the steering center, the roller 75b of the cam follower 75 returns to the boundary point 74d between the first and second curved convex surfaces 74b and 74c on the cam curved surface 74a.

On the other hand, when the driver further cuts the steering wheel 20 to the right from the above-described cutting position, the cam 74 and the pinion gear 77b further rotate to the left, and the roller 75b of the cam follower 75 has a steep slope portion of the second curved convex surface 74c. Roll to a steeper surface at 74c ₁ slope. As a result, the steering reaction force generating means 70 generates a larger steering reaction force and transmits it to the steering wheel 20.

  As the steering angle of the steering wheel 20 from the steering center increases, the sliding force and the frictional resistance between the rack gear 77a and the pinion gear 77b increase due to the elastic force of the elastic member 76, and the pinion gear A large torque in the direction opposite to the rotation direction of the rotation shaft 72B is applied to the rotation shaft 72B that holds 77b. In this steering reaction force generating means 70, the torque limiter 78 operates when the torque in the reverse rotation direction becomes the torque limiter operating torque described above, and the engagement between the third spur gear 71C and the pinion gear 77b. Is released. Therefore, the rotation of the pinion gear 77b stops, and the movement of the cam follower 75 and the elastic member 76 in the axial direction of the cam 74 stops at this position. As a result, when the steering wheel 20 is further cut, the roller 75b rolls in the circumferential direction on the steering reaction force characteristic curve of the second curved convex surface 74c at the stop position of the cam follower 75, and a larger steering reaction force is generated. generate.

  In the steering reaction force generating means 70 according to the first embodiment, when the steering wheel 20 is turned back from this position, the torque limiter 78 engages the third spur gear 71C and the pinion gear 77b, and the above-described turning back is performed. The steering reaction force is reduced by operating in the same manner as above.

  Further, when the steering wheel 20 is further cut to the right, the protrusion 74f of the cam 74 is locked by the roller 75b, and the rotation of the cam 74 and the first and third spur gears 71A and 71C is stopped. The driver cannot cut the steering wheel 20 any more, and recognizes the steering end.

  As described above, according to the steer-by-wire type steering apparatus 10 of the first embodiment, even when the steering angle of the steering wheel 20 from the steering center is the same, the steering reaction force generating means 70 causes a large steering during turning. A reaction force can be generated, and a smaller steering reaction force can be generated at the time of switching back. In other words, the steering device 10 according to the first embodiment is adapted to the steering reaction force transmitted to the steering wheel 20 according to the same situation as a conventional steering device in which such a steering wheel and a steering wheel are mechanically connected. Hysteresis characteristics can be provided in accordance with the turning or turning back of the wheel 20. For this reason, the steering device 10 of the first embodiment can give a good steering feeling without giving a sense of incongruity to a driver who has switched from a vehicle on which a conventional steering device is mounted.

  Further, in this steering device 10, a steering end for knowing the turning limit of the steered wheels 100L and 100R can be produced, and therefore, a good steering feeling without a sense of incongruity can be obtained.

  Furthermore, in the steering apparatus 10 of the first embodiment, such various effects can be realized only by a simple mechanical configuration without using an electric force such as an electric motor. And reliability can be improved.

  In the first embodiment, the steering shaft 21, the cam 74, and the cam follower position adjusting means 77 are provided in each of the first to third spur gears 71A to 71C. However, the third spur gear 71C is provided. Instead, the rotating shaft 72B of the cam follower position adjusting means 77 may be arranged coaxially with the steering shaft 21. In such a case, the rotation angle of the cam 74 corresponding to the steering angle of the steering wheel 20 and the operation amounts of the rack gear 77a and the pinion gear 77b in the cam follower position adjusting means 77 are set so as to have the same relationship as described above.

  Next, a second embodiment of the steering apparatus according to the present invention will be described with reference to FIGS.

  The steering device of the second embodiment has the same overall configuration as the steering device 10 of the first embodiment described above, and the difference is that the configuration of the steering reaction force generating means 70 of the first embodiment is partially changed. It is in.

  Reference numeral 170 in FIG. 7 indicates a steering reaction force generating means of the second embodiment. The steering reaction force generating means 170 includes first and second spur gears 71A and 71B similar to the steering reaction force generating means 70 of the first embodiment, and the steering shaft 21 is attached to the first spur gear 71A. The second spur gear 71B that is connected is integrally provided with a cam 174 that shares the rotating shaft 72A.

  The cam 174 of the second embodiment is provided with two protrusions 174e and 174f on the peripheral wall surface similar to the cam 74 of the first embodiment, and the peripheral wall surface between these protrusions 174e and 174f is cammed. Used as the curved surface 174a.

  Here, the cam curved surface 174 a provided on the cam 174 of the second embodiment is different from the cam curved surface 74 a of the first embodiment as a curved surface as if the steering reaction force characteristic curves having the same shape are arranged in the axial direction of the cam 174. Form. As the steering reaction force characteristic curve, the distance from the axis of the rotating shaft 72A to the contact surface of the cam follower 175 with the roller 175b is the shortest when the steering wheel 20 is located at the steering center, and from the steering center. In this case, the one that is curved in the circumferential direction so as to gradually become equal to the left and right as the steering angle of the steering wheel 20 to the left and right increases. That is, the cam curved surface 174a according to the second embodiment is a first and second curved convex surfaces that are parallel to the axis of the cam 174 and are symmetrical about the steering center reference line Sc shown in FIG. 174b and 174c. Even in the second embodiment, when the steering wheel 20 is at the steering center, the roller 175b is positioned at the boundary point 174d between the first and second curved convex surfaces 174b and 174c, while the steering wheel 20 is moved to the left. It is assumed that the roller 175b rolls on the first curved convex surface 174b when steered to the right, and the roller 175b rolls on the second curved convex surface 174c when steered to the right.

  Further, the steering reaction force generating means 170 of the second embodiment is in contact with the cam curved surface 174a of the cam 174, and a rod-shaped cam follower with an operation amount corresponding to the shape change of the cam curved surface 174a when the cam 174 rotates. A cam follower 175 that linearly moves in the axial direction of the main body 175a, and a roller 175b at the tip of the cam follower 175 is pressed against the cam curved surface 174a of the cam 174, and elastic members 176 such as a string-wound spring that expands and contracts as the cam follower 175 moves linearly. And are provided.

  In the second embodiment, the cam follower 175 includes a rod-shaped cam follower main body 175a, a roller 175b pivotally supported on one end side of the cam follower main body 175a, and a spring receiver 175c provided on the other end of the cam follower main body 175a. And a spring follower guide 175f for guiding the spring receiver 175c in the axial direction of the cam follower main body 175a. Then, the spring receiver 175c and the elastic member 176 are inserted from the open end of the cam follower guide portion 175f, and the respective end portions of the elastic member 176 are compressed by the inner wall surface of the closed end of the spring receiver 175c and the cam follower guide portion 175f. Hold on.

  Here, the cam follower guide portion 175f of the second embodiment is fixed to the housing 173 as shown in FIG.

  By the way, the steering reaction force generation means 170 of the second embodiment also produces the same steering reaction force hysteresis characteristic as the steering reaction force generation means 70 of the first embodiment.

  In the second embodiment, the steering reaction force shown in FIG. 8 differs depending on whether the steering wheel 20 is cut or not, by increasing the coefficient of friction between the roller 175b of the cam follower 175 and the cam curved surface 174a. Produces hysteresis characteristics. In FIG. 8, the steering angle from the steering center when the steering wheel 20 is steered to the right is positive, and the steering reaction torque applied to the steering shaft 21 at that time is positive. In FIG. 8, the basic characteristics of the steering reaction force when the friction coefficient between the roller 175b and the cam curved surface 174a is not increased are indicated by a two-dot chain line.

  That is, if the friction coefficient between them is high, the frictional force generated between the roller 175b and the cam curved surface 174a in the reverse rotation direction with respect to the cam 174 when the steering wheel 20 that the cam follower 175 compresses the elastic member 176 is cut. Since the torque is applied, the steering reaction torque applied to the steering shaft 21 can be increased. On the other hand, the frictional force between the roller 175b and the cam curved surface 174a is reduced by the elastic force of the elastic member 176 and the rolling direction of the roller 175b at the time of switching back the steering wheel 20 where the elastic member 176 extends. Even if the steering angle from the steering center is the same, the steering reaction torque applied to the steering shaft 21 can be reduced as compared with the time of turning.

  Here, at the start of turning from the steering center, the steering reaction torque is increased from the origin (steering reaction torque is “0”) regardless of whether the steering is to the right or the steering to the left. The steering reaction torque is generated on the above characteristic line without passing through the origin. Further, the increase amount of the steering reaction force torque at the time of cutting and the decrease amount of the steering reaction force torque at the time of turning back with respect to the steering reaction force torque of the basic characteristics are set to be characteristics that are substantially equal at each steering angle. .

  Therefore, in the second embodiment, the friction coefficient of the contact surface with the cam curved surface 174a of the roller 175b of the cam follower 175 is increased. For example, a member having a high friction coefficient may be disposed or coated on the contact surface, and the material of the roller 175b itself may have a high friction coefficient.

  Here, the friction coefficient sets a desired steering reaction torque to be generated on the steering shaft 21, the torque component accompanying the elastic force of the elastic member 176, and the frictional force between the roller 175b and the cam curved surface 174a. It is determined so that a desired steering reaction torque can be generated with the torque component accompanying the. Therefore, the optimum friction coefficient is set as appropriate according to the spring constant of the elastic member 176 and the desired steering reaction torque.

  Although the case where the friction coefficient of the roller 175b is increased is illustrated here, the friction coefficient of the cam curved surface 174a may be increased instead, and the friction coefficient of both the roller 175b and the cam curved surface 174a may be increased. May be raised.

  Even when the steering reaction force generating means 170 is configured as described above, when the steering angle of the steering wheel 20 is the same angle from the steering center, a large steering reaction force is generated when the steering wheel 20 is turned, and when the steering wheel 20 is turned back. A steering reaction force smaller than that can be generated. That is, also in the second embodiment, it is possible to provide a steering reaction force hysteresis characteristic according to the same situation as a conventional steering device in which a steering wheel and a steering wheel are mechanically coupled. For this reason, also in the steering device 10 of the second embodiment, it is possible to give a good steering feeling without giving a sense of incongruity to a driver who has switched from a vehicle equipped with a conventional steering device.

  Also in the second embodiment, since the steering end for knowing the turning limit of the steered wheels 100L and 100R can be produced by the projecting portions 174e and 174f of the cam 174, a good steering feeling without a sense of incongruity can be achieved. Obtainable.

  Furthermore, also in the steering device 10 of the second embodiment, such various effects can be realized by only a simple mechanical configuration without using electric power such as an electric motor, so that power consumption is reduced. And reliability can be improved.

  Here, the configuration between the roller 175b and the cam curved surface 174a in the second embodiment described above can also be applied to the steering reaction force generating means 70 of the first embodiment described above.

  According to this, for example, when the steering reaction force at the time of cutting according to the steering angle of the steering wheel 20 is set to the same magnitude as in the first embodiment, it is between the roller 175b of the cam follower 175 and the cam curved surface 174a. Since the torque component accompanying the friction of this part bears a part of the steering reaction torque that should be generated in the steering shaft 21, the spring constant of the elastic member 76 can be reduced. For this reason, the elastic member 76 can be smoothly expanded and contracted as compared with the first embodiment. Therefore, in addition to the same effects as those of the first embodiment, when the operation is performed, particularly when the steering wheel 20 is switched between cutting and switching back. Noise and vibration can be reduced.

  Further, for example, when a desired steering reaction torque cannot be generated on the steering shaft 21 only by the elastic force of the elastic member 76, a torque component accompanying friction between the roller 175b of the cam follower 175 and the cam curved surface 174a. Therefore, the desired steering reaction torque can be generated in the steering shaft 21 without increasing the spring constant of the elastic member 76 more than necessary. For this reason, in addition to the effect similar to Example 1, the increase in the sound and vibration at the time of the action | operation of the elastic member 76 can be suppressed.

  As described above, the steering device according to the present invention is useful as a technique for providing a steering feeling similar to that of a conventional steering device in which a steering wheel and a steering wheel are mechanically coupled. It is suitable for a technique that can be obtained without using electric power such as an electric motor.

1 is an overall configuration diagram of a steering apparatus according to the present invention. It is a fragmentary sectional view shown about the turning angle provision means of the steering device which concerns on this invention. It is a fragmentary sectional view shown about the structure of the steering reaction force generation | occurrence | production means in the steering apparatus of Example 1. FIG. FIG. 4 is a partial cross-sectional view of the steering reaction force generating means according to the first embodiment as viewed from line XX in FIG. 3. FIG. 4 is a partial cross-sectional view of the steering reaction force generating means of the first embodiment as viewed from the YY line of FIG. 3. It is a figure which shows the characteristic about the steering reaction force (steering reaction force torque) which the steering reaction force generation means of Example 1 generates according to the steering angle of a steering wheel. It is a fragmentary sectional view shown about the composition of the steering reaction force generating means in the steering device of Example 2. It is a figure which shows the characteristic about the steering reaction force (steering reaction force torque) which the steering reaction force generation means of Example 2 generates according to the steering angle of a steering wheel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Steering device 20 Steering wheel 21 Steering shaft 70 Steering reaction force generation means 71A 1st spur gear 71B 2nd spur gear 71C 3rd spur gear 72A, 72B Rotating shaft 73 Housing | casing 74 Cam 74a Cam curved surface 74b 1st curved convex surface 74b ₁ Steeply sloped part 74b ₂ Slowly sloped part 74c Second curved convex surface 74c ₁ Steeply sloped part 74c ₂ Slowly sloped part 74d Boundary point 74e, 74f Projection 75 Cam follower 75a Cam follower main body 75b Roller 75c Spring receiver 75d Caster mechanism 75e Caster shaft 75f Cam follower guide part 76 elastic member 77 cam follower positioning means 77a rack gear 77b pinion gear 77c rack gear guide portion 77c ₁ through holes 77d, 77e elastic member 78 a torque limiter 170 steering reaction force generating means 17 Housing 174 cam 174a cam curve 174b first curved convex surface 174c second curved convex surface 174d boundary points 174e, 175 cam follower 174f protruding portion 175a cam follower mainly 175b roller 175c spring receiving 175f cam follower guide portion 176 elastic member Sc steering center reference line

Claims (3)

A cam curved surface is formed on the peripheral wall surface, the cam rotates in the circumferential direction as the steering wheel rotates, and the cam follower abuts the cam curved surface of the cam and linearly follows the cam rotation. A steering apparatus comprising: an elastic member that presses the cam follower against the cam curved surface;
The cam curved surface extends in the circumferential direction so that the distance between the axis of the rotating shaft of the cam and the contact surface of the cam follower increases as the steering angle of the steering wheel from the steering center increases to the left and right. Each of the left and right curves is curved, and the gradient of each part in the circumferential direction of each of the left and right curved shapes is formed with a gradual slope at each part in the axial direction of the cam at the same steering angle,
The cam follower is moved toward the steep slope portion of the cam curved surface in the axial direction of the cam curved surface in response to the turning of the steering wheel, while the cam follower is gently inclined in the cam curved surface in response to the turning back of the steering wheel. A steering apparatus comprising cam follower position adjusting means for moving the cam follower toward the site in the axial direction of the cam. A cam curved surface is formed on the peripheral wall surface, the cam rotates in the circumferential direction as the steering wheel rotates, and the cam follower abuts the cam curved surface of the cam and linearly follows the cam rotation. A steering apparatus comprising: an elastic member that presses the cam follower against the cam curved surface;
The cam curved surface extends in the circumferential direction so that the distance between the axis of the rotating shaft of the cam and the contact surface of the cam follower increases as the steering angle of the steering wheel from the steering center increases to the left and right. It is formed by curving to the left and right,
A steering apparatus characterized in that a friction coefficient between the cam follower and the cam curved surface is increased.   The steering apparatus according to claim 1, wherein a protrusion is provided at each circumferential end on each of the left and right sides of the cam curved surface.

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