JPH10305779A - Steering device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce differential controlled variable and eliminate deviation of a neutral point by making a transmission ratio varying means of a steering transmission system connecting a steering handle and a steering wheel a frictional type continuously variable transmission. SOLUTION: When vehicle speed detected by a speed sensor 48 is inputted in an electronic controller(ECU) 46, the slide location of a ring body 14e of a continuously variable transmission 14 is determined according to speed and a gear shift instruction value for the slide is outputted. A gear ratio variable motor 30 revolves based on the gear shift instruction value, the revolution is transmitted to a worm gear 32, a guide member 34 moves along a slide pin 36, the ring body 14e of the continously variable transmission 14 moves upward at the time of low speed and moves downward at the time of high speed, each gear ratio is made small or large and the steering of a steering handle 10 can be performed in a quick or slow state. The ECU 46 determines the theoretical value of the gear ratio by the speed detected by the speed sensor 48, compares the value with a target steering angle and corrects deviation, and deviation of a neutral point can be eliminated by operational controlled variable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle steering system capable of changing a transmission ratio of a steering angle of a steering wheel to a steered wheel.

[0002]

2. Description of the Related Art Conventionally, as a steering device for varying a transmission ratio of a steering angle of a steering wheel to a steered wheel, there is a steering device disclosed in Japanese Patent Application Laid-Open No. 3-153467. This steering device includes a transmission ratio variable mechanism using a planetary gear differential mechanism on a steering shaft between a steering handle and a pinion connected to steered wheels.

[0003]

However, in this steering apparatus, since the variable transmission ratio mechanism is a planetary gear type differential mechanism, the differential motor is always driven during steering of the steering wheel, and power consumption is large. Had become something.

[0004] It is an object of the present invention to provide a vehicular steering apparatus that reduces the amount of differential control and does not cause a deviation of a neutral point.

[0005]

According to a first aspect of the present invention, there is provided a steering apparatus for a vehicle, wherein a transmission ratio varying means for varying a transmission ratio is provided in the middle of a steering transmission system connecting a steering wheel and a steered wheel. In a vehicle steering system provided with a control means for variably controlling a ratio variable means according to a vehicle running state, the transmission ratio variable means is a frictionless continuously variable transmission.

According to the vehicle steering system of the first aspect, the deviation of the neutral point can be eliminated with a small differential control amount by interposing the friction type continuously variable transmission in the middle of the steering transmission system. In the event of an abnormality, the gear ratio can be fixed to a predetermined gear ratio.

[0007] A vehicle steering system according to a second aspect of the present invention includes:
The frictionless continuously variable transmission of the vehicle steering system according to claim 1 is provided with a steering angle adjusting mechanism for adjusting a steering angle of the steered wheels to a target steering angle.

According to the second aspect of the present invention, since the frictionless continuously variable transmission includes the steering angle adjusting mechanism for adjusting the steering angle of the steered wheels to the target steering angle, the transmission ratio variable control is performed. During this, the steering angle can be adjusted to the target steering angle, and the deviation from the target steering angle can be eliminated.

Further, the vehicle steering system according to claim 3 is
The transmission ratio variable means is disposed between the two divided steering shafts, and when an axial load of a predetermined value or more is applied in the axial direction of the steering shaft, one of the two divided steering shafts is provided. Is configured to enter the inside of the other shaft.

According to the vehicle steering apparatus of the third aspect, when an axial load of a predetermined value or more acts on the steering shaft in the axial direction, one of the two divided steering shafts is connected to the inside of the other shaft. , And contracts in the axial direction, so that the load in the axial direction of the steering shaft can be absorbed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A steering apparatus for a vehicle according to a first embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a configuration diagram of a vehicle steering system 2. In the drawing, a reference numeral 10 denotes a steering handle, which is connected to an upper end of an upper steering shaft 12a of a vertically divided steering shaft. The lower end of the upper steering shaft 12a is connected to the input shaft 14a of the continuously variable transmission 14. Further, the continuously variable transmission 14 is provided with an output shaft 14d via a pressure adjusting cam 14c, and the output shaft 14d is connected to the lower steering shaft 12
b is connected to the upper end.

Here, the continuously variable transmission 14 is a friction type continuously variable transmission that uses a planetary cone 14b, which is an umbrella-type friction wheel, and a contact position between the planetary cone 14b and the inner peripheral surface of the ring body 14e. Is changed, the gear ratio (= the rotation speed of the input shaft / the rotation speed of the output shaft) is changed.

The variable gear ratio motor 30 includes a ring body 14e.
Is a motor for changing the contact position between the inner peripheral surface of the lens and the planetary cone 14b. When the gear ratio variable motor 30 rotates, the worm gear 32 rotates and the guide member 34
Moves along the slide pin 36, and the contact position between the inner peripheral surface of the ring body 14e and the planetary cone 14b is changed.

The continuously variable transmission 14 has a ring 1
By rotating the inner peripheral surface around the input shaft 14a and the output shaft 14d with the planetary cone 14b around the input shaft 14a and the output shaft 14d, the rotary shaft 4e also has a function as a differential mechanism. That is, teeth for meshing with the teeth of the worm gear 40 connected to the differential motor 38 are formed on the outer peripheral surface of the ring body 14e. Accordingly, when the differential motor 38 rotates, the ring body 14e rotates around the input shaft 14a and the output shaft 14d while bringing the inner peripheral surface into contact with the planetary cone 14b.

A pinion (not shown) is provided at a lower end of the lower steering shaft 12b, and the pinion is meshed with a rack bar 18 in the steering gear box 16. Further, one end of a tie rod 20 is connected to each end of the rack bar 18, and a knuckle arm 22 is connected to the other end of each tie rod 20.
The steered wheels 24 are connected via the.

The upper steering shaft 12a is provided with a steering angle sensor 42 for detecting the steering angle of the steering handle 10, and the lower steering shaft 12b is provided with a pinion angle sensor 44 for detecting the rotation angle of the pinion. Is provided. The steering angle of the steering wheel 10 detected by the steering angle sensor 42 and the rotation angle of the pinion detected by the pinion angle sensor 44 are input to an ECU (electronic control unit) 46. Further, the ECU 46 receives a vehicle speed output from a vehicle speed sensor 48 that detects the vehicle speed.

On the other hand, the ECU 46 controls the variable gear ratio motor 3
0 to change the gear ratio by changing the position of the ring body 14e with respect to 0, and the differential motor 3
The correction value for changing the target steering angle is output by changing the rotational position of the ring body 14e with respect to 8.

Next, the operation of the vehicle steering system 2 will be described. First, when the vehicle speed detected by the vehicle speed sensor 48 is input to the ECU 46, the shift position map 50 in the ECU 46 is referred to, and the continuously variable transmission 14 according to the vehicle speed is referred to.
The slide position of the ring body 14e is determined. Based on this, a shift instruction value for sliding the ring body 14e of the continuously variable transmission 14 is output from the ECU 46 to the gear ratio variable motor 30.

As a result, the variable gear ratio motor 30 rotates based on the shift instruction value, and this rotation is transmitted to the worm gear 32, and the guide member 34 moves along the slide pin 36, thereby causing the continuously variable transmission 14 to rotate. Ring body 14e
Is performed. That is, at low vehicle speed, the ring body 14e
However, while being moved upward in FIG. 1, the gear ratio is reduced, while at high vehicle speed, the ring body 14e
The gear ratio is increased by being moved downward at. Thus, the steering wheel 10 can be steered in a quick state at a low vehicle speed, and the steering wheel 10 can be steered in a slow state at a high vehicle speed.

When the vehicle speed detected by the vehicle speed sensor 48 is input to the ECU 46, a transmission ratio map 52 in the ECU 46 is referred to, and a transmission ratio corresponding to the vehicle speed, that is, a theoretical value of a gear ratio is obtained. The theoretical value of this gear ratio is
The target steering angle is obtained by multiplying the detected steering angle by the steering angle sensor 42 and multiplying the steering angle by the ECU 46 (gear ratio × steering angle = target steering angle).

The pinion angle detected by the pinion angle sensor 44 and input to the ECU 46 is compared with the target steering angle, and the deviation is input to the gear ratio controller 54.

The gear ratio controller 54 outputs a correction value for correcting the target steering angle to the differential motor 38. Thus, the differential motor 38 rotates according to the correction value and rotates the worm gear 40 to rotate the ring body 14e of the continuously variable transmission 14. Therefore, the continuously variable transmission 14 functions as a differential device, and the target steering angle can be corrected.

That is, in the conventional continuously variable transmission type steering apparatus, the steering handle 10 is steered while the vehicle is running at a constant vehicle speed, and the steering wheel 10 is decelerated to reduce the steering speed.
When 0 is returned, a phase shift (ad in the figure) occurs between the steering angle of the steering wheel 10 and the rotation angle of the pinion as shown in FIG.

On the other hand, in the continuously variable transmission 14 of the vehicle steering system 2 according to the first embodiment, the phase shift is performed by correcting the target steering angle in accordance with the steering angle during acceleration / deceleration. Can be eliminated. That is, FIG.
As shown in (b), when deceleration is performed when the steering angle is b, the ring body 14e of the continuously variable transmission 14 is moved upward in FIG. 1 to obtain a gear ratio corresponding to the vehicle speed. By doing so, the gear ratio is reduced. Accordingly, the continuously variable transmission 14
The target steering angle is corrected by rotating the ring body 14e and correcting the pinion angle from b to c. That is, even when the steering handle 10 is fixed, the turning angle of the steered wheels 24 gradually increases as the vehicle decelerates.

Thus, when the steering angle of the steering wheel 10 is returned to 0, the pinion angle can be set to 0, and the phase shift between the steering angle and the pinion angle (ad in the figure) can be eliminated. .

In the vehicle steering system 2,
The differential motor 38 is used only for correcting the target steering angle during acceleration / deceleration.
, The differential control amount can be reduced, and when the continuously variable transmission 14 is abnormal, the gear ratio can be fixed. Even so, the driver does not feel uncomfortable.

Next, a vehicle steering system 4 according to a second embodiment of the present invention will be described with reference to FIGS. In the description of the vehicle steering device 4, the same components as those of the vehicle steering device 2 according to the first embodiment are denoted by the same reference numerals as those of the components of the vehicle steering device 2. And the detailed description is omitted.

As shown in FIG. 4, the vehicle steering system 4 includes a variable gear ratio section 60 between the upper steering shaft 12a and the lower steering shaft 12b. Also, in this vehicle steering system 4, FIG.
As shown in FIG.
2 and a pinion angle sensor 44 are provided, and the steering angle of the steering wheel 10 detected by the steering angle sensor 42 and the rotation angle of the pinion detected by the pinion angle sensor 44 are input to the ECU 46.

On the other hand, the ECU 46 instructs the variable gear ratio section 60 to change the gear ratio by changing the position of the ring 14 e of the continuously variable transmission 14 and to change the gear ratio. A correction value for changing the target steering angle by changing the rotational position of the ring body 14e is output.

Next, a specific configuration of the gear ratio variable section 60 will be described with reference to FIGS. The gear ratio variable section 60 is mainly constituted by the continuously variable transmission 14 having a differential function. That is, as shown in FIG. 6 and FIG. 6
4. Worm gear 4 for rotating ring body 14e
0 and the like are provided.

The variable gear ratio motor 30 includes a housing 68.
The transmission motor shaft 30a
The first speed change gear 30b provided in the second speed change gear 6
4 is meshed with a gear provided at the center. Here, in addition to the gear that meshes with the first gear 30b provided at the center, the second gear 64 is provided with gears that mesh with the gears provided at the gear guide 62 at both ends. (See FIG. 7).

The transmission guide 62 has a bifurcated portion at each end. A gear that meshes with the second transmission gear 64 is provided at one bifurcation at one end, and a transmission guide holding pin 66 is provided at a bifurcated portion at the other end. A holding unit for holding is provided.
Further, a ring body 14e is provided at the center of the speed change guide 62.
Is provided with a ring body holding portion 62a for holding a part of the ring body.

Accordingly, the rotation of the variable gear ratio motor 30 rotates the second transmission gear 64, and the transmission guide 62 moves in the direction of the arrow shown in FIG. 7, that is, in the vertical direction of FIG. As a result, the ring body 14e, a part of which is held by the ring body holding portion 62a, also moves in the up-down direction in FIG. 8 and changes the contact position between the planetary cone 14b and the ring body 14e, thereby changing the gear ratio. .

The differential motor 38 has a housing 68
The worm gear 40 connected to the differential motor shaft 38a meshes with a gear formed on the outer peripheral surface of the ring body 14e.

Therefore, when the differential motor 38 rotates, the worm gear 40 rotates, and the ring body 14e can be rotated. Thus, the continuously variable transmission 14 can be used as a differential device, and the target steering angle can be changed.

The vehicle steering system 4 according to the second embodiment can perform the same control as the vehicle steering system 2 according to the first embodiment (see FIG. 2).
Thus, the vehicle steering system 2 according to the first embodiment
In the same manner as described above, the phase shift between the steering angle and the pinion angle can be eliminated with a small differential control amount.

In the gear ratio variable section 60,
Since both the variable gear ratio motor 30 and the differential motor 38 are fixed to the housing 68, the vehicle steering apparatus of the first embodiment, that is, the guide member for moving the ring body is moved. Responsiveness can be improved as compared with the vehicle steering system 2 in which the differential motor 38 moves, and rattling of each component can be reduced.

Next, a vehicle steering system according to a third embodiment of the present invention will be described with reference to FIGS. In the description of the vehicle steering system, the second
The same components as those of the vehicle steering device 4 according to the embodiment are denoted by the same reference numerals as those of the components of the vehicle steering device 4, and the detailed description is omitted.

In this vehicle steering system, the gear ratio variable unit 60 of the vehicle steering system 4 according to the second embodiment is changed to a gear ratio variable unit 80. This gear ratio variable section 8
0 has substantially the same configuration as the gear ratio variable section 60 according to the second embodiment, but when an axial load of a predetermined value or more acts on the steering shaft (steering shaft) in the axial direction. The lower steering shaft 12b is configured to enter the upper steering shaft 12a.

As shown in FIG. 9, the upper steering shaft 12a is formed of a cylindrical body having an inner circular hole extending in the axial direction therein. The lower steering shaft 12b has a hexagonal column at the upper part and a cylindrical column at the lower part, and the hexagonal column part of the lower steering shaft 12b is fitted to the output side rotation transmitting member 81 of the continuously variable transmission. That is, the output side rotation transmitting member 81 has an inner hexagonal hole extending in the axial direction corresponding to the shape of the hexagonal column of the lower steering shaft 12b inside. The hexagonal column portion of the lower steering shaft 12b is fitted into the hole.

The hexagonal column portion of the lower steering shaft 12b is provided with an engagement recess for engaging the head 82a of the resin pin 82.
The lower steering shaft 12b and the output-side rotation transmission member 81 are connected by the engagement of a with the engagement recess.

In the variable gear ratio portion 80, when an axial load of a predetermined value or more acts on the steering shaft in the axial direction, that is, the upward axial load on the lower steering shaft 12b due to kickback or the like becomes larger than the predetermined value. 10 or when a downward axial load acts on the upper steering shaft 12a to a predetermined value or more, such as when the occupant hits a steering wheel.
As shown in (1), the head 82a of the resin pin 82 is cut, and the lower steering shaft 12b enters the inside of the upper steering shaft 12a.

Therefore, in the vehicle steering system according to the third embodiment, it is possible to absorb a load in the axial direction that is equal to or larger than a predetermined value at the time of a vehicle collision or the like.

In the third embodiment,
When an axial load of a predetermined value or more acts on the steering shaft in the axial direction, the upper steering shaft 12a
The lower steering shaft 12b enters the inside of the lower steering shaft 12b, but when an axial load of a predetermined value or more acts on the steering shaft in the axial direction, the upper steering shaft 12a enters the lower steering shaft 12b. You may do so.

[0046]

According to the first aspect of the present invention, by disposing a friction type continuously variable transmission in the middle of the steering transmission system, it is possible to eliminate the deviation of the neutral point with a small differential control amount, and to further improve the abnormality. Sometimes the gear ratio can be fixed at a predetermined gear ratio.

According to the second aspect of the present invention, since the friction type continuously variable transmission is provided with the steering angle adjusting mechanism for adjusting the steering angle of the steered wheels to the target steering angle, the transmission ratio variable control is performed during the transmission ratio variable control. The steering angle can be adjusted to the target steering angle, and the deviation from the target steering angle vehicle steering system can be eliminated.

According to the third aspect of the invention, when an axial load of a predetermined value or more acts on the steering shaft in the axial direction, one of the two divided steering shafts enters the other shaft. Since it contracts in the axial direction, it is possible to absorb an axial load equal to or more than a predetermined value at the time of a vehicle collision or the like.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a vehicle steering system according to a first embodiment.

FIG. 2 is a block diagram of the vehicle steering system according to the first embodiment;

FIG. 3 is a diagram for explaining a relationship between a steering angle and a gear ratio.

FIG. 4 is a diagram for explaining a mounting position of a variable gear unit of the vehicle steering system according to the second embodiment;

FIG. 5 is a block diagram of a vehicle steering system according to a second embodiment;

FIG. 6 is a diagram for explaining a variable gear unit of the vehicle steering system according to the second embodiment.

FIG. 7 is a diagram for explaining a variable gear unit of the vehicle steering system according to the second embodiment.

FIG. 8 is a diagram for explaining a variable gear unit of the vehicle steering system according to the second embodiment.

FIG. 9 is a diagram for explaining a variable gear unit of the vehicle steering system according to the third embodiment.

FIG. 10 is a diagram for explaining a variable gear unit of the vehicle steering system according to the third embodiment.

[Explanation of symbols]

2,4 ... Vehicle steering device, 10 ... Steering handle, 12a ... Upper steering shaft, 12b ... Lower steering shaft, 14 ... Continuously variable transmission, 14a ... Input shaft, 14b ... Planetary cone, 14c ... Pressure regulating cam, 14d
... output shaft, 14e ... ring body, 16 ... steering gear box, 18 ... rack bar, 20 ... tie rod, 22
... knuckle arm, 24 ... steering wheel, 30 ... variable gear ratio motor, 38 ... differential motor, 42 ... steering angle sensor, 44 ... pinion angle sensor, 46 ... ECU, 48 ... vehicle speed sensor, 6
0,80: Gear ratio variable section.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification code FI B62D 13:00 (72) Inventor Tadashi Kawamuro 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation

Claims (3)

[Claims] 1. A control means for interposing transmission ratio variable means for changing a transmission ratio in the middle of a steering transmission system connecting a steering handle and a steered wheel, and variably controlling the transmission ratio variable means according to a vehicle running state. The vehicle steering system according to claim 1, wherein the transmission ratio varying means is a frictionless continuously variable transmission. 2. The vehicle steering system according to claim 1, wherein the friction type continuously variable transmission includes a steering angle adjusting mechanism for adjusting a steering angle of the steered wheels to a target steering angle. 3. The transmission ratio variable means is disposed between the two divided steering shafts, and is divided into two when an axial load of a predetermined value or more acts on the steering shaft in the axial direction. The vehicle steering apparatus according to claim 1, wherein one of the steering shafts is configured to enter into the other shaft.