JPH0630601Y2 - Power steering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a power steering device that utilizes hydraulic pressure to assist the steering force of a vehicle.

(Prior Art) In a conventionally known power steering device using hydraulic pressure, the steering reaction force is controlled by utilizing the switching reaction force of the spool of the switching valve.

(Problems to be Solved by the Present Invention) In the configuration in which the steering reaction force is controlled by utilizing hydraulic pressure as described above, since the hydraulic circuit is required, the entire mechanism becomes complicated and the piping Due to such problems, there is a problem that a large installation space is required.

An object of the present invention is to eliminate the above-mentioned conventional drawbacks by electrically controlling the steering reaction force, eliminating the need for piping when hydraulic pressure is used.

(Means for Solving the Problem) This invention makes a member such as a spool contact with both sides of an action portion of an oscillating lever that oscillates in accordance with the operation of a pinion shaft, and a solenoid is provided on both sides of the member such as the spool. The push rod of each solenoid is brought into contact with both ends of a member such as a spool, and a spring for maintaining the neutral position of the member such as the spool acts on the push rod, at least in accordance with an increase or decrease in vehicle speed. A controller that controls the exciting current of the solenoid and variably controls the pressing force of the push rod against the member such as the spool is provided, and the force of the swing lever that swings against the pushing force of the push rod is used as the steering torque. A torque sensor for detection is provided and the movement of the spool of the control valve is controlled according to the output signal of this torque sensor, It is characterized in that it is configured to control the output of the commander.

(Effect of the Invention) According to the device of the present invention, since the steering reaction force can be controlled by controlling the exciting current of the solenoid, piping or the like is not required unlike the case where hydraulic pressure is used.

(Embodiment of the present invention) FIG. 1 is a schematic view of the entire apparatus, which includes a handle 1
The pinion shaft 3 is connected to the input shaft 2 connected to the pinion shaft 3, and the pinion 4 is formed on the pinion shaft 3.

The rack 5 that meshes with the pinion 4 has its both ends connected to wheels 8 via a steering link 6 and a knuckle arm 7. The rack 5 can be moved left and right by the driving force of the power cylinder 9.

Further, the pinion shaft 3 is supported by a pair of bearings 11 and 12 provided on the gear box 10 as shown in FIG. 2. On both sides of the bearings 11 and 12, as shown in FIG. Spaces 13 and 14 are formed, and the bearings 11 and 12, that is, the pinion shaft 3 can be swung left and right within the range of the spaces 13 and 14.

As shown in FIG. 4, a circular portion 16 of a swing lever 15 is engaged with the pinion shaft 3 which is swingable left and right, and when the swing lever 15 swings left and right, the swing lever 15 15 is the fulcrum
It swings around 17.

The tip of the swing lever 15 thus swingable, that is, the acting portion 19 is inserted into the insertion hole 20 of the plunger 18, and the acting portion 19 has a torque sensor formed of a piezoelectric element.
21 is provided, and the torque sensor 21 is connected to the first controller a that controls the exciting current of the solenoid 22 of the control valve S.

Then, on the outside of both ends of the plunger 18, the solenoid is
23, 24 push rods 25, 26 are provided, and springs 27, 28 are made to act on the large diameter portions of the bush rods 25, 26,
Normally, the spring force of the springs 27 and 28 causes the large diameter portions of the push rods 25 and 26 to act on the end surface of the plunger 18, and the plunger 18 is kept in the normal position shown in the figure.

The solenoids 23 and 24 as described above are connected to the second controller b to which the vehicle speed signal from the vehicle speed sensor 29 is input. Furthermore, the output signal from the first controller a is also input to the second controller b via the discharge pressure sensor 30 and the discharge pressure detection unit 31.
Since the output signal from the first controller a controls the power cylinder 9, the output signal is detected by the discharge pressure sensor 30 and the discharge pressure detector 31 and fed back.

The control valve S, as shown in FIG.
A rod portion 33 is formed at one end of the rod portion 33, and the rod portion 33 is inserted into the solenoid 22. Then, the rod portion 33
The spring force of the neutral springs 34, 35 is applied to the tip of the spool and the spool end opposite to the rod portion, and the spool 32 is normally kept in the neutral position shown in the figure.

The above controllers a and b are shown as one control mechanism A in FIG.

Therefore, the vehicle speed of the vehicle is detected by the vehicle speed sensor 29, and the discharge pressure, which is information to be fed back, is detected by the discharge detection unit 31. The second controller b controls the exciting current to the solenoids 23 and 24 according to the detected vehicle speed and discharge pressure, and adjusts the thrust of the push rods 25 and 26.

When the handle 1 is turned while the thrusts of the push rods 25 and 26 are controlled in this way, the following is obtained.

That is, when a load is applied to the wheels 8, the knuckle arm 7, the steering link 6 and the rack 5 are in a fixed state, so that the pinion 4 rolls on the rack 5 while moving the pinion shaft 3 to the bearings 11, Swing in the range of 12 spaces 13 and 14.

When the pinion shaft 3 swings in this manner, the swing lever 15 rotates about the fulcrum 17 and moves the plunger 18 to the left or right.

At this time, as described above, since the exciting current that depends on the vehicle speed and the pump discharge pressure flows through the solenoids 23 and 24, the thrust proportional to the current acts on the push rod.

Therefore, when the swing lever 15 tries to swing as described above, the thrust forces of the push rods 25 and 26 together with the spring forces of the springs 27 and 28 act as a reaction force against the movement of the plunger 18. . Then, the reaction force to the plunger 18 is transmitted to the steering wheel 1 via the pinion shaft 3 and the input shaft 2 and becomes a steering reaction force.

In this way, when the swing lever 15 rotates to move the plunger 18, the action portion 19 of the swing lever 15 is inserted into the insertion hole.
The torque sensor 21 provided on 20 is pressed. Then, the pressing force at this time eventually changes according to the exciting currents of the solenoids 23 and 24, and the voltage signal output from the torque sensor 21 changes according to the change.

The torque signal from the torque sensor 21 is input to the first controller a, and the first controller a controls the exciting current to the solenoid 22 of the control valve S according to the torque signal.

As described above, the solenoid 22 moves the spool 32 leftward or rightward according to the direction of the current, and controls the movement amount of the spool 32 in proportion to the magnitude of the current.

Then, by moving the spool 32 to the left or right, one of the chambers of the power cylinder 9 is communicated with the pump P, and the other chamber is connected to the tank T to operate the power cylinder 9.

Further, the movement amount of the spool 32 is controlled according to the magnitude of the exciting current, and the larger the movement amount is, the larger the flow rate supplied to the power cylinder 9 is.

In this embodiment, since the steering reaction force can be controlled in proportion to the exciting currents of the solenoids 23 and 24, the steering reaction force can be increased if necessary.

Further, for example, in the mechanism shown in FIG. 4, when the steering reaction force is to be exerted only by the springs 27 and 28 without using the solenoids 23 and 24, the characteristic becomes as shown in FIG.

That is, when the same output F ₀ is assumed, it is desirable that the steering reaction force be increased as the vehicle speed increases from a to c. Therefore, in order to increase the steering reaction force as the vehicle speed increases, the rocking lever 15 must be rocked by that much. Because, if the displacement x of the swing lever is not increased, the spring 27,
This is because the spring force of 28 does not increase.

In order to increase the steering reaction force as described above, the sliding lever
When the displacement amount of 15 is increased, the rigid feeling is deteriorated and the steering feeling is deteriorated.

On the other hand, in the case of this embodiment, as is clear from the characteristic diagram of FIG. 7, if the exciting currents of the solenoids 23 and 24 are controlled, the lever displacement amount x ₀ of the swing lever 15 becomes constant. Then, the steering reaction force can be changed by controlling the exciting currents of the solenoids 23 and 24. In other words, the swing lever 15
Since the desired steering reaction force can be exerted even if the vehicle is not swung greatly, the problem of reducing the rigid feeling as described above does not occur.

FIG. 9 shows a second embodiment, in which the swing lever 15 is
A torque sensor 21 composed of a strain gauge is provided at the base of the action portion 19 of the above, and the other configurations are the same as those of the above-described embodiment.

Further, in this embodiment, the steering reaction force is detected by the torque sensor 21 composed of a strain gauge, and the detection signal is transmitted to the first controller a.

The third embodiment shown in FIG. 10 is a spool of the control valve S.
At both ends of 32, push rods 38, 39 of solenoids 36, 37
The solenoid 22 of the first embodiment described above.
It is a unit of 24.

Therefore, the exciting current to the solenoids 36 and 37 is controlled according to the vehicle speed and the pump discharge pressure, and the control signal of the torque sensor 21 is fed back to the solenoids 36 and 37.

[Brief description of drawings]

Drawings 1-6 show the 1st example of this invention,
1 is a schematic view of a power steering device, FIG. 2 is a sectional view of a gear box portion, FIG. 3 a, b are sectional views of a bearing portion, and FIG. 4 is a sectional view taken along line IV-IV of FIG. FIG. 5 is a block diagram of a control mechanism, FIG. 6 is a cross-sectional view of a control valve, FIG. 7 is a graph showing control characteristics, FIG. 8 is a graph showing control characteristics when a solenoid is not used, and FIG. FIG. 10 is a sectional view of a main part of the second embodiment, and FIG. 10 is a sectional view of a control valve of the third embodiment. 3 ... pinion shaft, 9 ... power cylinder, 15 ... rocking lever, 19 ... acting part, 21 ... torque sensor, S ... control valve, 23, 24 ... solenoid, 25, 26 ... push Rod, b ... Controller, 27, 28 ... Spring,
32 …… Spool.

Claims (1)

[Scope of utility model registration request] 1. A member such as a spool is brought into contact with both sides of an action portion of a rocking lever that rocks in accordance with the operation of a pinion shaft, and solenoids are provided on both outer sides of the member such as the spool. The solenoid's push rod is brought into contact with both ends of a member such as a spool, and a spring for maintaining the neutral position of the member such as a spool acts on the push rod to control the exciting current of the solenoid at least according to the increase / decrease in vehicle speed. However, a controller for variably controlling the pressing force of the push rod against the member such as the spool is provided, and a torque sensor for detecting the force of the swing lever that swings against the pushing force of the push rod as steering torque is provided. , The structure of controlling the output of the power cylinder by controlling the movement of the spool of the control valve according to the output signal of the torque sensor. Power steering apparatus to.