JP4700498B2 - Vehicle steering system - Google Patents

Description

  The present invention includes a steering angle ratio variable mechanism that changes a steering angle ratio between a steering angle of a steering mechanism and a steering angle of a steering member (hereinafter referred to as “steer angle”) between the steering mechanism and the steering mechanism. The present invention relates to a vehicle steering apparatus.

2. Description of the Related Art Conventionally, a vehicle steering apparatus including a steering angle ratio variable mechanism between a steering mechanism and a steering mechanism is known (see, for example, Patent Document 1).
In the vehicle steering apparatus disclosed in Patent Document 1, a steering shaft between a steering member (steering handle) and a steering gear box is divided into a front shaft portion, an intermediate shaft portion, and a rear end shaft portion from the steering member side. A steering angle ratio variable mechanism (transmission ratio variable mechanism) is provided at the intermediate shaft portion.
The intermediate shaft portion includes a housing that houses the rudder angle ratio variable mechanism, upper and lower locking shafts provided above and below the housing, an upper locking shaft for connecting the upper locking shaft and the tip shaft portion, and the like. It comprises a speed joint, and a lower constant velocity joint for connecting the lower locking shaft and the rear end shaft portion. The housing is provided with a cable case (retracting portion) that is deformed by being pressed by relative displacement between the housing and the locking shaft.
JP 2001-211151 (paragraph 0026, FIG. 1 and FIG. 3)

However, since the distance between the constant velocity joints above and below the steering shaft is increased in the vehicle steering device described in Patent Document 1, a reverse amount absorbing member for absorbing the reverse amount of the steering gear box at the time of a collision is provided. There is a problem that installation space is lost.
As described above, the vehicle steering apparatus disclosed in Patent Document 1 has a problem in that the degree of freedom in design is low because the installation space is limited.

  Furthermore, the vehicle steering device of Patent Document 1 requires a dedicated design for making the steering angle ratio variable mechanism, and replacement with an electric power steering device or the like is difficult.

  Accordingly, an object of the present invention is to provide a vehicle steering apparatus that is space-saving and that can easily replace a steering mechanism that uses a steering angle ratio variable mechanism with another steering mechanism.

  As a means for solving the above-mentioned problem, the invention of a vehicle steering apparatus according to claim 1 is directed to a steering mechanism including a steering member operated to steer a wheel, and to steer the wheel. In a vehicle steering apparatus including a steering mechanism and a steering angle ratio variable mechanism interposed between the steering mechanism and the steering mechanism, the steering angle ratio variable mechanism rotates from the steering member. A transmission gear that is speed-changed by a motor between a stator gear coupled to an input shaft through which a bevel is transmitted via a bevel gear, and a driven gear coupled to a pinion gear meshed with a rack provided in the steering mechanism so as not to be relatively rotatable. It is characterized by being connected through the

According to the vehicle steering apparatus of the first aspect, when the driver operates the steering member, the rotation of the steering member is transmitted to the steering angle ratio variable mechanism via the steering mechanism. The speed is changed by the ratio variable mechanism and transmitted to the steering mechanism that steers the wheels. Since the rudder angle ratio variable mechanism is connected to the stator gear with a bevel gear interposed on the input shaft, the rudder angle ratio variable mechanism can be arranged so as to cross obliquely with respect to the input shaft. It becomes possible to reduce the size of the whole by restricting.
Further, when assembling the rudder angle ratio variable mechanism, the input-side stator gear can be engaged with the bevel gear, and the output-side pinion gear can be engaged with the rack of the steering mechanism, so that it can be installed in the vehicle steering apparatus. Therefore, assembly is easy.
Furthermore, the steering angle ratio variable mechanism is replaced with another steering mechanism that does not use the steering angle ratio variable mechanism (for example, an electric power steering device or a hydraulic power steering device). It is only necessary to insert the pinion gear portion of the mechanism, and the replacement is easy as compared with the conventional vehicle steering apparatus.

  A vehicle steering apparatus according to a second aspect is the vehicle steering apparatus according to the first aspect, wherein the stator gear is formed in a cylindrical shape and has a stator internal gear portion on an inner peripheral surface thereof. The driven gear is rotatably housed in the stator gear and has a driven internal gear portion, and the transmission gear is provided in the stator internal gear portion and the driven internal gear portion. Each of the gears is formed of a flexible gear having a number of teeth different from the number of teeth of the stator internal gear portion, and a wave generator rotated by the motor is disposed in the transmission gear. It is characterized by that.

  According to the invention of the vehicle steering apparatus of the second aspect, since the rudder angle ratio variable mechanism is configured by a harmonic drive (registered trademark), a reliable power transmission characteristic and a high reduction ratio can be obtained.

  The invention of a vehicle steering apparatus according to claim 3 is the vehicle steering apparatus according to claim 1 or 2, wherein the steering angle ratio variable mechanism has a center axis that is the center line of the input shaft. The stator gear is provided with a bevel gear at one end in the direction of the central axis, and the stator internal gear portion at the other end in the direction of the central axis via an extension portion having a predetermined length. The transmission gear and the driven gear are arranged on the inner periphery of the stator gear.

  According to the vehicle steering apparatus of the third aspect, the rudder angle ratio variable mechanism is arranged such that the center axis is inclined with respect to the center line of the input shaft. The central axis of the rudder angle ratio variable mechanism is arranged in a substantially V shape with respect to the input shaft, and is disposed in a state where the coupling portion between the rudder angle ratio variable mechanism and the pinion gear is wrapped. The overall length is shortened, and space can be saved.

  According to the vehicle steering apparatus of the present invention, a vehicle steering apparatus that is space-saving and easy to assemble and that can easily replace a steering mechanism that uses a steering angle ratio variable mechanism with another steering mechanism is provided. Can be provided.

Next, a vehicle steering apparatus according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a schematic view showing an installation state of a vehicle steering apparatus according to an embodiment of the present invention.

≪Configuration of vehicle steering system≫
As shown in FIG. 1, the vehicle steering device S varies a steering mechanism 1 that is driven according to a steering operation of a steering member 10 performed by a driver via a steering angle ratio variable mechanism 2, thereby turning a steering mechanism. 3 is a device that steers a wheel (not shown). This vehicle steering device S is mainly composed of a steering mechanism 1, a steering angle ratio variable mechanism 2, a steering mechanism 3, and a control device 4.

≪Configuration of steering mechanism≫
As shown in FIG. 1, the steering mechanism 1 transmits the rotation of the steering member 10 operated by the driver to the steering angle ratio variable mechanism 2. The steering mechanism 1 includes a steering member 10 that is operated to steer a wheel, an upper steering shaft 12 that rotates integrally with the steering member 10, and an operation that detects an input (steering angle) to the steering member 10. An input detection unit 13, a universal joint 14 connected to the lower end of the upper steering shaft 12, an input shaft 15 connected to the lower end of the universal joint 14, and a main driving bevel gear 16 provided on the input shaft 15 (FIG. 3). See), and mainly consists of.

The steering member 10 is a so-called steering wheel, and the upper end of the upper steering shaft 12 is fixed to the lower end of the central portion.
The upper steering shaft 12 is a shaft rod that rotates together with the steering member 10, and an input shaft 15 is disposed at the lower end of the upper steering shaft 12 with a universal joint 14 interposed therebetween.

  The operation input detection unit 13 is installed on the upper steering shaft 12 and includes a steering angle sensor that detects a rotation state of the steering member 10, that is, a steering angle, and generates a detection signal. The operation input detection unit 13 is electrically connected to the control device 4. Further, it is assumed that a turning angle sensor (rack position sensor) (not shown) for detecting the turning angle is provided, and the detection signal is output to the control device 4.

The universal joint 14 is a joint member that can connect the upper steering shaft 12 and the input shaft 15 with their directions changed, and is provided so that the steering member 10 can be disposed at an appropriate inclination angle. . As shown in FIG. 1, an input shaft 15 is connected to the lower side of the universal joint 14. The input shaft 15 is disposed at almost the same height as the steering angle ratio variable mechanism 2 from the steering mechanism 3.
The control device 4 outputs a control signal for controlling the rudder angle ratio variable mechanism 2. The control device 4 is electrically connected to a vehicle speed sensor 5 for detecting the vehicle speed, and the vehicle speed is inputted. It has become so.

<Configuration of input shaft>
As shown in FIG. 1, the input shaft 15 is a shaft bar that rotates with the steering member 10 when the rotation from the steering member 10 is transmitted. The input shaft 15 is for transmitting the rotation transmitted from the steering member 10 to the input shaft 15 via the upper steering shaft 12 and the universal joint 14 to the steering angle ratio variable mechanism 2 by the main driving bevel gear 16 (see FIG. 3). It is a member.

  FIG. 2 is an enlarged plan view of a main part showing an installation state of the vehicle steering apparatus according to the embodiment of the present invention. FIG. 3 is an enlarged cross-sectional view when viewed from the direction of the arrow XX in FIG. 2 and shows a state when the cover member is removed. FIG. 4 is an exploded perspective view of FIG.

As shown in FIG. 1, the lower end of the input shaft 15 is covered with a case body 17 fitted with a main driving bevel gear 16 (see FIGS. 3 and 4) and fixed to a steering gear box 32 (see FIG. 2). ).
As shown in FIGS. 3 and 4, a plurality of bearings B <b> 1 and B <b> 2 for rotatably mounting the input shaft 15 to the case body 17 are installed at the lower end portion of the input shaft 15 (see FIG. 2). ).

<Configuration of main driving bevel gear (bevel gear)>
As shown in FIGS. 3 and 4, the main driving bevel gear 16 is engaged with the driven bevel gear 21 a to transmit the rotation of the input shaft 15 to the steering angle ratio variable mechanism 2. The center line O1-O1 of the input shaft 15 of the steering mechanism 1 and the center axis O2-O2 of the steering angle ratio variable mechanism 2 are arranged so as to be inclined in a direction shifted from each other by the intersection angle θ.

The crossing angle θ is an arbitrary angle, and the angle can be appropriately adjusted by adjusting the inclination of the tooth surfaces of the main driving bevel gear 16 and the driven bevel gear 21a.
The main driving bevel gear 16 and the driven bevel gear 21a correspond to a “bevel gear” described in the claims.

≪Configuration of rudder angle ratio variable mechanism≫
As shown in FIGS. 3 and 4, the rudder angle ratio variable mechanism 2 can change the rudder angle ratio between the steered angle of the wheel and the steered angle of the steering member 10 rotated by the driver's steering operation according to the vehicle speed or the like. And is interposed between the steering mechanism 1 and the steering mechanism 3. In other words, the steering angle ratio variable mechanism 2 appropriately shifts the rotation input from the main driving bevel gear 16 of the input shaft 15 to the stator gear 21 by the wave generator 23 and the transmission gear 22, and the steering mechanism from the pinion gear 25. 3 is a device for transmitting to three racks 31.
A housing 28 as a unit case of the steering angle ratio variable mechanism 2 is rotatably covered by a cover member C (see FIGS. 1 and 2) fixed to the steering gear box 32 with a bearing B4 interposed therebetween. Yes.

  The steering angle ratio variable mechanism 2 is, for example, a rotation transmission ratio variable means using a wave generator 23, and includes a wave gear reducer such as a so-called harmonic drive (registered trademark). The rudder angle ratio variable mechanism 2 includes a stator gear 21 connected to an input shaft 15 via a main driving bevel gear 16 and a driven gear connected to a pinion gear 25 meshed with a rack 31 provided in the steering mechanism 3 so as not to be relatively rotatable. 24, a transmission gear 22 that decelerates the rotation of the stator gear 21 to make the driven gear 24 differential, and a wave generator 23 that waves the transmission gear 22 by a rotor (cam) 23b provided on the motor shaft Ma of the motor M. It is mainly configured (see FIGS. 5A and 5B).

  The steering angle ratio variable mechanism 2 includes a motor M for rotating the wave generator 23, a lock mechanism 26 for restricting the rotation of the motor M, a spiral cable 27, a motor M and a lock. A housing 28 for housing the mechanism 26, a cover member C for fixing the housing 28 to the steering gear box 32, and a pinion gear 25 splined to the driven gear 24 are provided (FIGS. 1 and FIG. 1). 2).

<Configuration of stator gear>
As shown in FIGS. 3 and 4, the stator gear 21 is a gear for transmitting the rotation of the input shaft 15 to the transmission gear 22. The stator gear 21 is made of metal formed in a cylindrical shape, and is fixed to the lower housing portion 28 a of the housing 28. A driven bevel gear 21a is integrally formed on the lower end outer peripheral surface of the stator gear 21, a stator internal gear portion 21b is integrally formed on the upper end inner peripheral surface, and an inner peripheral surface below the upper end inner peripheral surface is formed on the inner peripheral surface. A driven storage portion 21c in which the driven gear 24 is rotatably stored is formed.
In other words, the stator gear 21 is provided with a driven bevel gear 21a in one end in the direction of the central axis O2-O2, and a stator internal gear portion at the other end in the direction of the central axis O2-O2 through an extension portion having a predetermined length. 21 b is provided, and a transmission gear 22 and a driven gear 24 are arranged on the inner periphery of the stator gear 21.

  The driven bevel gear 21 a is a gear provided to tilt the steering angle ratio variable mechanism 2 with respect to the input shaft 15, and is provided on the outer periphery of the lower end portion of the steering angle ratio variable mechanism 2 provided on the top of the pinion gear 25. Has been placed. The cylindrical stator gear 21 meshes the lower driven bevel gear 21a with the main driven bevel gear 16 at the lower end of the input shaft 15, and rotatably inserts the driven gear 24 with the pinion gear 25 mounted thereon. It is inserted. Thereby, each member which comprises the rudder angle ratio variable mechanism 2 other than the pinion gear 25 shown in FIG. 3 is arrange | positioned in the position above the pinion gear 25. FIG. As a result, the entire length of the steering shaft 11 is shortened by substantially the entire height H of the steering angle ratio variable mechanism 2 (see FIG. 3).

The stator internal gear portion 21 b is a gear for transmitting the rotation of the stator gear 21 to the transmission gear 22, and includes an internal gear such as a circular spline formed on the upper inner surface of the cylindrical stator gear 21.
A fitting member 29 for preventing the driven gear 24 stored in the driven storage portion 21c from falling off is fitted in the opening on the rack 31 side (lower side) in the driven storage portion 21c.

<Configuration of transmission gear>
The transmission gear 22 is a gear for shifting the rotation of the stator gear 21 and transmitting it to the driven gear 24. For example, the transmission gear 22 is a flexible gear formed in a ring shape by a metal material that is elastically deformed such as a flexspline. A spline-shaped spline formed on the outer peripheral surface of the transmission gear 22 has a number of teeth different from the number of teeth of the stator internal gear portion 21b (for example, two fewer than the number of teeth of the stator internal gear portion 21b). The tooth profile is integrally formed.

5A is an enlarged cross-sectional view in the direction of the arrow Y-Y in FIG. 3, and FIG. 5B is an enlarged cross-section showing a state when rotated 90 degrees from the state of FIG. 5A. FIG.
As shown in FIGS. 5A and 5B, the transmission gear 22 is deformed into an elliptical shape by being engaged with an elliptical ball bearing 23 a mounted on the outer periphery of the wave generator 23. It is assembled with. For this reason, in the transmission gear 22, two tooth profile portions formed in a portion having a long radius mesh with the stator internal gear portion 21b, and the other tooth profile portions mesh with the stator internal gear portion 21b through a gap. It is not in a state.

  The transmission gear 22 is internally provided with a rotor 23b of a wave generator 23 that is rotated by a motor M via a ball bearing 23a (see FIG. 3). In the transmission gear 22, the control device 4 rotates and vibrates the wave generator 23 based on the vehicle speed signal from the vehicle speed sensor 5, thereby appropriately changing the rotation of the stator gear 21 and transmitting it to the driven gear 24 (see FIG. 3). (See FIG. 1).

As shown in FIGS. 3 and 4, the upper half of the outer surface of the transmission gear 22 has a number of teeth different from the number of teeth of the transmission gear 22 (for example, two less than the number of teeth of the stator internal gear portion 21 b). The internal gear portion 21b of the stator having the number of teeth) is internally provided and meshed. On the other hand, the lower half of the outer surface of the transmission gear 22 is internally provided and meshed with the driven internal gear portion 24b of the driven gear 24 having the same pitch and the same number of teeth as the transmission gear 22.
Note that when the wave generator 23 is stopped, the transmission gear 22 is decelerated by two pitches having different numbers of teeth and transmitted to the driven gear 24 when the stator internal gear portion 21b rotates once. .
The principle of gear shifting, etc.
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It is described in.

<Configuration of driven gear>
The driven gear 24 is a stepped cylindrical internal gear for transmitting the rotation of the transmission gear 22 to the pinion gear 25, and is made of a ring-shaped rigid body that is rotatably inserted into the driven storage portion 21 c of the stator gear 21. . A ring-shaped cutout portion 24a for rotatably fitting the fitting member 29 is formed on the outer peripheral end of the driven gear 24 on the rack 31 side.
In the opening on the stator internal gear portion 21b side of the driven gear 24, for example, the gear meshes with the transmission gear 22 and is driven by two teeth less than the number of teeth of the stator internal gear portion 21b with the same pitch as the transmission gear 22. An internal gear portion 24b is formed.
A spline joint portion 24c is formed in the center of the driven gear 24 so as to be aligned with the spline shaft portion 25a of the pinion gear 25 and rotate integrally therewith, and a bearing B3 is mounted on the open end of the pinion gear 25 side. ing.
The number of teeth of the driven internal gear portion 24b is the same as that of the transmission gear 22, and is formed, for example, by two less than the number of teeth of the stator internal gear portion 21b.

<Configuration of wave generator and motor>
The wave generator 23 is a so-called wave generator that rotates the wave by rotating the rotor 23b attached to the motor shaft Ma of the motor M to rotate the transmission gear 22 at a variable speed. The wave generator 23 is composed of an elliptical cam and a ball bearing 23a disposed on the outer periphery thereof, and is fixed to a motor shaft Ma that rotates together with the rotor 23b (see FIGS. 5A and 5B).

As shown in FIGS. 3 and 4, the motor M is a power source of electric power steering that assists the steering force of the steering member 10 with a driving force, and includes, for example, a DC brushless motor. The motor M includes a motor shaft Ma to which a wave generating cam provided in the wave generator 23 is fixed, and is fixed in the housing 28 (see FIGS. 5A and 5B).
When the motor M rotates, the transmission gear 22 rotates in the stator gear 21 in a state of being deformed into an elliptic shape along the shape of the cam, and rotates the coaxial driven gear 24. That is, since the number of teeth of the driven gear 24 is smaller than the number of teeth of the stator gear 21, when the wave generator 23 makes one rotation, the driven gear 24 rotates at a reduced speed by a difference in the number of teeth in the direction opposite to the rotation direction of the wave generator 23. It has become.
On the other hand, when the steering member 10 is rotated by the steering operation, the input shaft 15 (stator gear 21) is rotated, and a motor operating angle (motor operating angle = rotational angle of the motor M × tooth number difference / number of teeth of the driven gear 24) is added. Then, it is transmitted to the pinion gear 25 which is an output shaft (see FIG. 1).

The lock mechanism 26 manually locks the motor M so that it does not rotate when the electric power steering function of the vehicle steering device S is in a failed state or when the ignition switch is turned off. It is to be in the state of. The lock mechanism 26 includes, for example, a solenoid (not shown) that moves the plunger when the current from the control device 4 flows through the coil, and one end connected to the solenoid plunger and the other end to the motor shaft Ma of the motor M. A lock lever (not shown) that engages with a lock groove of the fixed lock holder, and the lock holder (not shown) are provided.
A central portion of the lock lever is provided with a return spring for urging the lock lever toward the lock holder and a support portion for swingably supporting the lock lever.

  When the lock lever and the lock holder are engaged and the motor shaft Ma of the motor M (see FIGS. 5A and 5B) is locked, the motor M and the wave generator 23 cannot rotate. . At this time, when the steering member 10 rotates, the input shaft 15 rotates in conjunction with it, and the driven gear 24 is rotated through the transmission gear 22 without being shifted. For this reason, even if some abnormality occurs in the motor M and the wave generator 23, the rotation of the steering member 10 is reliably transmitted to the steering mechanism 3 (see FIG. 1).

  For example, when the ignition switch is turned on and the vehicle steering device S is turned on, the lock mechanism 26 is energized to the solenoid, and the lock lever is rotated by the suction force of the solenoid to be unlocked. The transmission ratio variable function of the steering ratio variable mechanism 2 can be executed. That is, the motor operating angle is added to the rudder angle rotated by the steering operation of the steering member 10 and is input to the rack 31.

  The spiral cable 27 is used to electrically connect the motor M provided in the rotating housing 28 and the control device 4 provided on the vehicle body side so as to be rotatable in the forward rotation direction and the reverse rotation direction. It consists of a flexible flat cable wired in a spiral. The spiral cable 27 is provided in a casing that includes a rotating case 27a that is connected to the motor M side and rotates together, and the other that is locked to the vehicle body side and does not rotate. Yes.

<Housing configuration>
As shown in FIG. 3, the housing 28 includes a stepped cylindrical body that is mounted with a stator gear 21 in the lower opening and rotates together with the stator gear 21. The motor M and the lock mechanism 26 are housed inside the housing 28. ing. The housing 28 is rotatably disposed in the cover member C via a bearing B4 installed on the outer periphery.
A driven bevel gear 21a is disposed at the lower end of the housing 28, and a pinion gear 25 is disposed at a lower portion thereof. The motor M is stored in the central storage portion 28b of the housing 28, and the lock mechanism 26 is stored in the upper storage portion 28c.

<Configuration of pinion gear>
The pinion gear 25 is a gear that transmits the rotation of the driven gear 24 to the rack 31, and is a transmission member that converts the rotation of the steering angle ratio variable mechanism 2 into a linear movement in the vehicle width direction by meshing with the rack 31. The pinion gear 25 is rotatably disposed in the cover member C (see FIG. 1) with a bearing B5 mounted at the center.

≪Configuration of steering mechanism≫
The steered mechanism 3 is a mechanism for steering the wheels, and includes a rack and pinion mechanism including a pinion gear 25 and a rack 31. In addition, the steering mechanism 3 includes tie rods 33 that are installed at both ends of the rack 31 and are connected to the wheels via a knuckle (not shown) (see FIG. 1).

≪Assembly and operation of rudder angle ratio variable mechanism≫
Next, assembly and operation of the steering angle ratio variable mechanism 2 in the vehicle steering apparatus S according to the embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 4, when the steering angle ratio variable mechanism 2 is assembled to the vehicle steering device S, first, the stator gear 21 is inserted into the lower housing portion 28a of the housing 28 in which the bearing B4 is mounted. Next, the driven gear 24 fitted with the bearing B3 is inserted into the driven storage portion 21c of the stator gear 21, and the fitting member 29 is inserted into the opening of the driven storage portion 21c and fixed with a set screw. The spline shaft 25a of the pinion gear 25 is inserted into the driven gear 24 and fixed.

  A transmission gear 22 is attached to the periphery of the elliptical wave generator 23. Then, since the annular transmission gear 22 is formed of a metal elastic material or the like, it has an elliptical shape. A spiral cable 27 is installed above the motor M which is a driving source of the wave generator 23 with a lock mechanism 26 interposed.

  As a result, the members of the steering angle ratio variable mechanism 2 are assembled as shown in FIG. 3, and the housing 28, the stator gear 21 and the pinion gear 25 are covered with the cover member C, so that the members shown in FIGS. Thus, it becomes a unitized state.

When the steering angle ratio variable mechanism 2 is installed between the steering mechanism 1 and the steering mechanism 3 of the vehicle steering device S, the pinion gear 25 is meshed with the rack 31 from the lateral direction, and the driven bevel gear 21a is moved to the main driving bevel gear 16. Since the rudder angle ratio variable mechanism 2 can be assembled by meshing from the lateral direction, the assembling work is easy.
Even in the case of manual steering that does not include a power steering device, a main driving bevel gear 16 is installed at the lower end of the steering shaft 11, and the driven bevel gear 21 a of the steering angle ratio variable mechanism 2 is engaged with the main driving bevel gear 16. Can be easily retrofitted to engage the rack 31 of the steering mechanism, and the steering angle ratio variable mechanism 2 can be installed. Of course, the same applies to the production line.

  As shown in FIG. 3, the vehicle steering apparatus S is arranged such that the center axis O2-O2 of the steering angle ratio variable mechanism 2 is tilted in a V shape with respect to the center line O1-O1 of the input shaft 15 and input. On the central axis O2-O2 above the driven bevel gear 21a that meshes with the main drive bevel gear 16 of the shaft 15, a housing 28 that houses the motor M, the wave generator 23, and the lock mechanism 26, and a spiral cable 27 are arranged.

For this reason, the portion indicated by H in FIG. 3, that is, the steering angle ratio variable mechanism 2 can be removed from the steering shaft 11, and can be provided compactly by being unitized with the existing steering mechanism.
As a result, the steering angle ratio variable mechanism 2 itself can be reduced in weight in addition to being easily installed in a small vehicle or the like.

Next, the operation of the vehicle steering device S will be described.
The vehicle steering device S shown in FIG. 1 has, for example, a vehicle speed detected by the vehicle speed sensor 5 and an operation input detected by the operation input detection unit 13 when the ignition switch is turned on and the steering member 10 is operated by a steering wheel. (Steering angle) and a turning angle detected by a turning angle sensor (not shown) are input to the control device 4. Then, the control device 4 calculates the target rudder angle ratio based on the vehicle speed, and a control signal based on the target rudder angle ratio is output to the rudder angle ratio variable mechanism 2. Based on this control signal, the motor M of the steering angle ratio variable mechanism 2 is driven to give the steering member 10 a steering angle ratio corresponding to the target steering angle ratio. In addition, in order to determine whether or not the rudder angle ratio is the target rudder angle ratio, the actual rudder angle ratio is calculated using the detected rudder angle and steered angle.

When a failure of the motor M is detected, the control device 4 outputs a control signal to the solenoid, and locks the lock mechanism 26 that fixes the plunger to the motor shaft Ma.
Then, the operation of the wave generator 23 of the rudder angle ratio variable mechanism 2 is stopped, and the steering member 10 and the wheels are directly connected, so that steering is performed with a constant transmission ratio.

  When the failure of the motor M is resolved, the control device 4 outputs a control signal to the solenoid of the lock mechanism 26 and enters the unlocked state, thereby releasing the connection between the steering member 10 and the wheel. As a result, the operation of the wave generator 23 of the rudder angle ratio variable mechanism 2 is resumed.

  In this case, when the driver operates the steering member 10 shown in FIG. 1, the steering input of the steering member 10 is input to the upper steering shaft 12, the universal joint 14, and the input shaft 15. As shown in FIG. 3, this operation input is transmitted from the main drive bevel gear 16 of the input shaft 15 to the steering angle ratio variable mechanism 2 via the driven bevel gear 21a.

  In the steering angle ratio variable mechanism 2, the motor M is driven by a signal from the control device 4 to rotate the wave generator 23. Then, as shown in FIGS. 5 (a) and 5 (b), the transmission gear 22 is elastically deformed, and the meshing position with the stator internal gear portion 21b and the driven internal gear portion 24b is sequentially moved. The rotation of 23 is transmitted to the driven internal gear portion 24b. In this case, for example, the driven internal gear portion 24b rotates at the same speed as the wave generator 23, but the driven internal gear portion 24b rotates by the number of teeth of two sheets every time the wave generator 23 makes one rotation. Is delayed and rotated, and the wheels are steered via the pinion gear 25 and the rack 31.

  The present invention is not limited to the above-described embodiment, and various modifications and changes can be made within the scope of the technical idea. The present invention extends to these modifications and changes. Of course.

≪Modification≫
FIG. 6 shows a modification of the vehicle steering apparatus according to the embodiment of the present invention. For example, the transmission gear 22 of the steering angle ratio variable mechanism 2 shown in FIG. 5 includes a planetary gear mechanism 6 as shown in FIG. The transmission gear 62 of the steering angle ratio variable mechanism 2 </ b> A using a speed reduction mechanism may be used. That is, the steering angle ratio variable mechanism 2A is provided on the motor shaft Ma of the motor M (see FIG. 3), the sun gear 61, and the stator internal gear portion 21b (see FIG. 3) of the sun gear 61 and the stator gear 21. And a carrier gear 63 that supports each of the transmission gears 62.
In this case, the carrier 63 provided in the transmission gear 62 is connected to a planetary gear that meshes with a driven internal gear portion of a driven gear (not shown).

Even in this case, the rotation of the stator gear 21 can be decelerated by the transmission gear 62 and the rotation of the transmission gear 62 is transmitted to the pinion gear 25 via the carrier 63 and the driven gear 24.
Further, the vehicle steering device S may be configured to include an electric power steering device.

It is the schematic which shows the installation state of the steering apparatus for vehicles which concerns on embodiment of this invention. It is a principal part enlarged plan view which shows the installation state of the steering apparatus for vehicles which concerns on embodiment of this invention. It is an expanded sectional view when it sees from the arrow XX direction of FIG. 2, and shows a state when the cover member is removed. FIG. 4 is an exploded perspective view of FIG. 3. (A) is an expanded sectional view of the YY line direction of FIG. 3, (b) is an expanded sectional view which shows a state when it rotates 90 degree | times from the state of (a). The modification of the steering device for vehicles concerning the embodiment of the present invention is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steering mechanism 2,2A Steering angle ratio variable mechanism 3 Steering mechanism 6 Planetary gear mechanism 10 Steering member 15 Input shaft 16 Main drive bevel gear (bevel gear)
21 Stator gear 21a Driven bevel gear (bevel gear)
21b Stator internal gear section 22, 62 Transmission gear 23 Wave generator 23a Ball bearing 24 Driven gear 24b Driven internal gear section 25 Pinion gear 28 Housing 31 Rack M Motor O1-O1 Center line O2-O2 Center axis S Vehicle steering system

Claims (3)

A steering mechanism including a steering member operated to steer the wheels;
A steering mechanism for steering the wheels;
In a vehicle steering apparatus comprising: a steering angle ratio variable mechanism interposed between the steering mechanism and the steering mechanism,
The steering angle ratio variable mechanism includes a stator gear coupled to an input shaft to which rotation from the steering member is transmitted via a bevel gear;
A driven gear connected to a pinion gear meshed with a rack provided in the steered mechanism so as not to be relatively rotatable;
A vehicle steering apparatus characterized in that the two are connected via a transmission gear that is shifted by a motor. The stator gear is formed in a cylindrical shape and has a stator internal gear portion on the inner peripheral surface,
The driven gear is rotatably housed in the stator gear and has a driven internal gear portion,
The transmission gear includes a flexible gear that is provided in the stator internal gear portion and the driven internal gear portion and meshes with each other, and has a number of teeth different from the number of teeth of the stator internal gear portion. With
2. The vehicle steering apparatus according to claim 1, wherein a wave generator that is rotated by the motor is disposed in the transmission gear. The steering angle ratio variable mechanism is arranged such that a center axis is inclined with respect to a center line of the input shaft,
The stator gear is provided with a bevel gear at one end in the direction of the central axis, and the stator internal gear portion is provided at the other end in the direction of the central axis via an extension portion having a predetermined length.
The vehicle steering apparatus according to claim 1 or 2, wherein the transmission gear and the driven gear are arranged on an inner periphery of the stator gear.

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