JPH02246873A - Rear wheel steering gear - Google Patents

Abstract

PURPOSE:To obtain a rear wheel steering gear to enable the most appropriate steering corresponding to the running condition of a vehicle by constructing the rear wheel steering gear in such a way as to operate stretching link members to stretch according to the output of the first and second power source and control the output of the first and second power source individually according to the running condition of the vehicle. CONSTITUTION:Stretching members 32 are connected to the one sides of the arms 34 of a first and a second trapezoidal link units A, B, the other sides of the arms are fixed, connecting members 42 are hung across the other ends of both arms, and rear wheels 23, 24 are mounted at these connecting members 42 so as to form a first and a second steering gears Sr, Sl. A first motor 25 is linked to the stretching link member 32 of the first steering gear Sr, a second motor 26 is linked to the stretching link member 32 of the second steering gear Sl, and these stretching link members 32 are operated to stretch according to the output of the first and second motors 25, 26 as well as a controller 35 for controlling the output of the first and second motors 25, 26 individually according to the running condition of a vehicle is connected to the first and second motors 25, 26.

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention connects individual steering devices to the left and right rear wheels, controls the steering angles of the left and right rear wheels individually, and maintains the vehicle under optimal conditions. The present invention relates to a rear wheel steering device that allows steering by using the steering wheel.

(Prior Art) The conventional rear wheel steering device shown in FIG.
Connected to sight rod 3.4.

When the handle 1 is turned, the handle 1a rotates together with the handle 1, and this rotational force is transmitted to the front wheels and the side rod 3.4 through the engagement between the rack and the binion of the steering device 2. The side rod 3.4 moves in either the left or right direction in the drawing and steers the front wheels 7.8 via a knuckle arm 5.6 connected to the side rod 3.4.

In addition, a rear wheel steering device 9 is provided separately from the front wheel steering device 2, and this rear wheel steering device 9 includes a motor 10, a shaft driver 11 linked to the motor 10, and a shaft driver 11 that is directly connected to the motor 10. The main elements are an encoder 12 and an electromagnetic brake 13. The output shaft (not shown) of the motor 1O is linked to a shaft (not shown) of the shaft driver 11, and side rods 14, 15 are connected to both ends of this shaft, respectively.

When the motor 10 rotates, this rotational force is transmitted to the side rods 14, 15 via the shaft driver 11. The rotational force of the motor lO is applied to the side rod 14.
15, the side rod 14.15 moves to either the left or right direction in the drawing, and also moves the rear wheel 18.19 via the knuckle arm 16.17 connected to this side rod 14.15. Turn the wheel.

The steering device 9 configured in this manner has its motor lO
and an electromagnetic brake 13 are connected to a controller 20, while a vehicle speed sensor 21,
A front wheel steering angle sensor 22 provided on the side rod 4 of the front wheel and an encoder 12 are connected.

Thus, when the steering wheel 1 is turned and the front wheels 7.8 are steered, the front wheel steering angle sensor 22 detects the actual front wheel steering angle, the vehicle speed sensor 21 detects the actual vehicle speed, and these output signals are detected. The controller 20 is powered manually.

The motor IO rotates according to the input signal.

Furthermore, when the motor IO rotates, the encoder 12 detects the actual rotation amount of the motor IO, and feeds back this output signal to the controller 20 to feedback-control the rear wheel steering angle.

That is, in this rear wheel steering device, the rear wheels 18 and 19 are both connected to a single rear wheel steering device 9 that is linked with a motor IO, and the rotational force of the motor 10 controlled by the controller 20 is transferred to the rear wheels 18 and 19. .19 to control the steering of the rear wheels 18.19.

Therefore, both the left and right rear wheels 18 and 19 are steered by the same angle in the same direction. In this way, the left and right rear wheels are steered in the same manner, so when the vehicle speed is low, the rear wheels can be steered in opposite phases, and when the vehicle is high speed, the rear wheels can be steered in the same phase, but the left and right rear wheels can be steered individually. It is not possible.

(Problems to be Solved by the Present Invention) The conventional rear wheel steering device as described above cannot steer both the left and right rear wheels individually, so the steering angle of the rear wheels can be optimized depending on the driving conditions. Unable to control the condition.

Therefore, there was a problem in that the vehicle could not be steered under optimal conditions depending on the driving conditions of the vehicle.

An object of the present invention is to provide a rear wheel steering device that can perform optimal steering according to the driving conditions of a vehicle.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a steering device that steers rear wheels using the power of a power source such as a motor, and a steering device that steers rear wheels using the power of a power source such as a motor, and a steering device that steers rear wheels using power from a power source such as a motor. In the rear wheel steering device provided with a controller for controlling the output of
A trapezoidal link unit is provided, a telescopic link member is connected to one side of one arm of the first and second trapezoidal link units, one side of the other arm is fixed, and a connecting member is attached to the other sides of both arms. A rear wheel is attached to this connecting member to form a first and second steering device, a first power source is linked to a telescoping link member of the first steering device, and a second power source is connected to a telescoping link member of the second steering device. The power sources are linked and the telescopic link member is configured to extend and contract according to the output of the first and second power sources, and the output of the first and second power sources is individually controlled according to the running conditions of the vehicle. The controller is connected to the first and second power sources.

(Action of the present invention) As described above, a steering device in which a power source such as a motor is linked is individually connected to both left and right rear wheels via its trapezoidal link unit, and the output of the office power source is transmitted by a controller. Since they are controlled individually, the steering angles of both the left and right rear wheels can be controlled individually.

(Effects of the Present Invention) According to the rear wheel steering device of the present invention, both the left and right rear wheels can be controlled individually.

Therefore, the steering angles of the left and right rear wheels can be made different, and both the left and right rear wheels can be steered toward the toe-in side or toward the toe-out side.

Furthermore, by inputting information on the brake state, reverse state, and throttle opening of the vehicle into the controller, the rear wheel turning angle can be individually controlled according to the acceleration/deceleration and traveling direction of the vehicle.

Therefore, the vehicle can be steered under optimal conditions depending on the driving conditions of the vehicle.

(Embodiment of the present invention) In the first embodiment of the present invention shown in Fig. 1.2, a first steering device Sr and a second steering device SfL are connected to the left and right rear wheels 23 and 24, respectively. .

The first and second steering devices Sr and Sl2 include the first and second steering devices Sr and Sl2.
Two motors 25 and 26 are provided, and reduction gears 27 made of worm gears are connected to output shafts 25a and 26a of these first and second motors, respectively. Further, a pinion 28 is attached to the tip of the gear shaft 27a of the reducer 27, and the rotational force of the first and second motors is transmitted to the first and second trapezoidal link units A and H via this pinion 28. .

Since the configurations of the 1.2 trapezoidal link units A and B are the same, regarding the 1.2 link units A and B of each army, please refer to the 1st trapezoidal link unit A shown in Figure 2.3. , will be explained using the same reference numerals.

The first trapezoidal link unit A shown in FIG. 2.3 has a bushing 30a attached to a support member 2.9 provided on one side of the chassis
The arm 30 is fitted with a. This arm 30 is rotatable relative to the support member 29 via a bush 30a.

Furthermore, a gear box 31 containing the reduction gear 27 is installed on the other side of the chassis a, and the gear shaft 27 of the reduction gear 27 is mounted on the other side of the chassis a.
A rack 32a formed on a telescopic link member 32 is meshed with a pinion 28 attached to a. Furthermore, a ball joint 33 is provided on the other side of the telescopic link member 32, and the telescopic link member 3 is connected to the telescopic link member 3 via this ball joint 33.
2. It is connected to the arm 34. The arm 34 is configured to freely rotate in accordance with the stroke of the telescopic link member 32 in the left-right direction in FIG. 3 and the stroke in the front-back direction in the drawing due to the spring action of a suspension (not shown).

The arms 30.34 configured as described above span the connecting member 42 at their tips, and connect both the arms 30.34 and the connecting member 42 in a swingable manner, and the rear wheels 23. 24 are each installed.

In both the above-described steering devices Sr and Sl, when the first and second motors 25 and 26 rotate, the rotational force is transmitted to the telescopic link member 32 through the gear reducer 27 and the pinion 28 and the rack 32a. Then, the telescopic link member 32 telescopically operates. When the telescopic link member 32 expands and contracts, the arm 34 moves in either direction of the arrow y in the drawing via the ball joint 33, thereby steering the rear wheels 23 and 24 individually.

1.2 steering device Sr, SJ as above
I connects these 1.2 motors 25, 26 to the controller 35. On the other hand, this controller 35 includes a front wheel steering angle sensor 22 provided on the side rod 4 on the front wheel side, and a telescopic link member 32 on each of the rear wheels 23 and 24 side.
Rear wheel steering angle sensors 36 and 37 provided at the rear wheels are connected, and a vehicle speed sensor 38, a brake switch 39, a reverse gear switch 40, and a throttle opening sensor 41 are also connected.

Then, the output signals detected by these sensors and the on/off signals of the switches are manually input to the controller 35. On the other hand, the controller 35 processes these human power signals and individually determines rear wheel steering angle target values for the rear wheels 23 and 24.

This determination is carried out by patterns A to K in the rudder angle determination pattern table in Figure 4.
The process is performed as follows according to each pattern shown in .

(a) As shown in patterns A and H in Figure 4, when the vehicle speed is low or low, the steering direction of both left and right rear wheels is reversed to the steering direction of the curved wheel, and the steering angle is is made larger and the steering angles of both rear wheels are made equal.

(b) When the vehicle speed is high as shown in patterns C and D in Figure 4, the steering direction of the left and right rear wheels is set in the same phase as the steering direction of the front wheels, contrary to the above patterns A and B. At the same time, the steering angle is made smaller. Furthermore, the steering angles of both the left and right rear wheels are made equal.

Note that the patterns A to D are similar to the conventional patterns.

(c) Patterns E to H in FIG. 4 are patterns in which the brake switch and reverse gear switch are all turned off. Therefore, its steering mode is similar to the patterns A to D above. However, in this pattern, the left and right rear wheel steering angles are different from each other as shown in FIG.

In other words, in the case of patterns E and F where the vehicle speed is low,
When the vehicle turns due to steering, the steering angle of the inner wheels whose turning radius becomes smaller is increased, and the steering angle of the outer wheels is decreased.

In addition, in the case of patterns G and H, where the vehicle speed is high, when the vehicle turns, the steering angle of the outer wheels, where the load increases due to the centrifugal force of the vehicle, is made smaller, and the inner wheels, where the load decreases. I am trying to increase the rudder angle.

(d) Furthermore, as shown in Patterns I and J in Figure 4, when decelerating with the steering wheel in neutral, both the left and right rear wheels are moved to the toe-in side while making the steering angles of the left and right rear wheels equal. I'm trying to change direction. This also maintains the straightness of the vehicle.

Further, as shown in pattern K in the figure, when the vehicle is traveling backwards, the left and right rear wheels are steered to the toe-out side while the left and right rear wheels are made equal in steering angle regardless of the operation of the steering wheel. In other words, the vehicle is steered toward toe-in in the direction of travel when traveling in reverse, thereby maintaining the straightness of the vehicle.

As described above, according to the rear wheel turning angle determination pattern shown in FIG. 4, in addition to the conventional pattern of four items, a pattern of six new items is added. Then, the left and right wheels can be steered to the toe-in side or toe-out side by individually changing the steering angles of the left and right rear wheels or by individually changing the steering direction.

The rear wheel steering device configured as described above is different from the conventional one in that when the steering wheel 1 is turned, the front wheels 7.8 are steered, and the output signal of the front wheel steering angle sensor 22 for detecting the front wheel steering angle is manually input to the controller 35. The same is true.

Further, the controller 35 is configured to control the steering angle sensor 22.
In addition, vehicle speed sensor 38, throttle opening sensor 41
It receives the output signal of the brake switch 39 and the opening ON/OFF signal of the reverse gear switch 40. Then, the controller 35 determines the rear wheel turning angle target value of each of the left and right rear wheels 23.24 according to these human power signals, and outputs the output signal of this rear wheel turning angle target value to the first and second motors 25.24. 2
6. Manpower individually.

Further, the first and second motors 25.26 that have received the output signal from the controller 35 as described above rotate according to the output signal from the controller 35, and the rear wheels 23.24 rotate according to the direction and amount of rotation. Turn the wheels individually.

Further, at the same time as the rear wheels 23, 24 are steered, the output signal of the rear wheel steering angle sensor 36, 37 that detects the actual steered angle is fed back to the controller 35, and the rear wheels 23, 24 are
The steering angle of the vehicle is controlled by feedback.

Note that the worm gear of the reducer 27 is connected to the 1.2 motor 25.
．． The advance angle of the gear teeth is set small so that only the output from the 26 side is transmitted. And rear wheel 23.24
Worm gear prevents reverse rotation even if external force is applied from the side.
This prevents the rear wheels 23 and 24 from wobbling.

The second embodiment shown in FIG. 5 shows another embodiment in which the motors serving as the power sources for the 1.2 steering devices Sr and Sn are replaced with power cylinders.

In the second embodiment shown in FIG. 5, a hydraulic valve (2) which is switched in accordance with an output signal from a controller 35 is connected between a power cylinder S and a pump P. Further, the power cylinder S has a piston 44 slidably installed inside its cylinder body 43, and the piston 44 is provided with a rod 44a which is a telescopic link member of the present invention. Then, oil chambers R, R2 are defined on both sides of the piston 44, and
The tip of the rod 44a is connected to the arm 34 via a ball joint 33.

Since the configuration other than the above is the same as that of the first embodiment, the above description will be quoted as is and the description will be omitted.

As a result, when the hydraulic valve ■ is switched in response to the output signal of the controller 35, and the pump P and one of the oil chambers R, , R2 of the power cylinder S communicate with each other, for example, the oil chamber R1, the other oil chamber R2 and tank T are connected. In this way, when the internal oil chambers R1 and R2 communicate with the pump P and the tank T, pressure oil is introduced into the oil chamber R2, and the hydraulic oil in the oil chamber R2 on the opposite side is returned to the tank T. therefore,
The piston 44 of the power cylinder S moves upward in the drawing in response to the supply of pressure oil. Furthermore, when the pump P and the other oil chamber R2 communicate with each other, it is natural that the piston 44 moves downward in the drawing, contrary to the above.

When the piston 44 of the power cylinder S moves in the vertical direction in the drawing as described above. This stroke amount is joint 3
3 to the 1st and 2nd trapezoidal link units A and B, and the rear wheels 23 and 24 are steered individually, which is the same as in the first embodiment.

A pair of springs 45 are provided on both sides of the piston 44, and when the power cylinder S is under no load, the piston 44 is held at the normal position shown in the figure by the spring force of the springs 45.

The spring 45 also has a two-ale safe function that holds the piston 44 at the normal position and keeps the rear wheels neutral when pressure oil is no longer supplied to the power cylinder S.

According to the above-mentioned Embodiment 1.2, both the left and right rear wheels can be controlled individually.

Therefore, the steering angles of the left and right rear wheels can be made different, and both the left and right rear wheels can be steered toward the toe-in side or toward the toe-out side.

Furthermore, by manually inputting information on the vehicle's braking state, reversing state, and throttle opening to the controller, the rear wheel turning angle can be individually controlled according to the vehicle's acceleration/deceleration and traveling direction.

Therefore, the vehicle can be steered under optimal conditions depending on the driving conditions of the vehicle.

[Brief explanation of drawings]

Drawings 1 to 4 show a first embodiment of this invention.
Fig. 1 is a circuit diagram, Fig. 2 is a plan view of the trapezoidal link unit, Fig. 3 is an enlarged view of the main parts of the trapezoidal link unit, Fig. 4 is a rear wheel steering angle determination pattern table calculated by the controller, and Fig. 5 is a circuit diagram of the second embodiment, and FIG. 6 is a circuit diagram of a conventional rear wheel steering device. S r...first steering device, S2... second
Steering device, A... first trapezoidal link unit,
B...Second trapezoidal link unit, 23.24--Rear wheel, 25...First motor, 26--Second motor, 30
-...Arm, 32--Telescopic link member, 34--Arm, 35--Controller, 42--Connection member,
S-...Power cylinder, 44a... Rod which is the telescopic member of the present invention.

Claims (1)

[Claims] A rear wheel steering device that includes a steering device that steers the rear wheels using power from a power source such as a motor, and a controller that inputs driving conditions of the vehicle and controls the output of the power source. A link unit is provided, a telescoping link member is connected to one side of one arm of the first and second trapezoidal link units, one side of the other arm is fixed, and the connecting member is stretched across the other sides of both arms. , a rear wheel is attached to this connecting member to constitute first and second steering devices, a first power source is linked to the telescopic link member of the first steering device, and a second power source is connected to the telescopic link member of the second steering device. The controller is configured to link the power sources and to extend and retract the telescopic link member according to the outputs of the first and second power sources, and to individually control the outputs of the first and second power sources according to the driving conditions of the vehicle. a rear wheel steering device connected to the first and second power sources.