JPH03227775A - Power steering device for vehicle - Google Patents

Abstract

PURPOSE:To save energy by constituting a reaction force mechanism so that hydraulic force based on reaction hydraulic pressure from a reaction force hydraulic pressure generating circuit which is controlled according to a vehicle speed functions to a pressure applied element in an apparatus including the reaction force mechanism having the pressure-applied element for transmitting a reaction force to a steering wheel side. CONSTITUTION:A pinion to be engaged with a rack of a steering mechanism is provided at an end, and an intermediate ring 24 of a displacement expansion lever 23 is freely rotatably fitted to an intermediate section of a pinion shaft 14 which is rotated interlocked with a steering wheel. A tip ball part 29 of the displacement expansion lever 23 is engaged with a through hole 32 formed on a spool 31 of a control valve V for controlling supply/ exhaustion of hydraulic oil to a power cylinder C. A reaction force mechanism is integrally provided with the control valve V, while the reaction force mechanism is constituted of pistons 36, 37 which are pressure applied elements energized by springs 34, 35, mutually communicated reaction force hydraulic oil chambers R1, R2 which are partitioned by the respective pistons 36, 37, a reaction force hydraulic pressure generating circuit A for generating reaction force hydraulic pressure to be supplied to the respective reaction force hydraulic oil chambers R2, R2, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a power steering device for a vehicle, and more particularly to a power steering device for a vehicle comprising a reaction force mechanism that transmits a reaction force to a steering wheel side.

[Conventional technology]

This type of power steering device for a vehicle is disclosed in, for example, Japanese Utility Model Application Publication No. 1134573, and includes, as a reaction force mechanism, a pusher that transmits the reaction force to the handle side, and a part of the hydraulic fluid discharged from the hydraulic pump. A reaction oil pressure generation circuit has a variable throttle valve that throttles (hydraulic oil diverted by a diversion valve) according to an increase in vehicle speed, and generates a reaction oil pressure that is low pressure at low vehicle speeds and high pressure at high vehicle speeds; A so-called hydraulic reaction force mechanism is employed, which includes a reaction oil chamber that presses a pusher according to the reaction oil pressure supplied from a hydraulic pressure generation circuit to increase the reaction force.

[Problem to be solved by the invention]

In the conventional vehicle power steering device described above, the reaction force pressure at low vehicle speeds is lowered to reduce the reaction force transmitted to the steering wheel side, and the power steering characteristics at low vehicle speeds are lightened (low rigidity). ), and also increases the reaction force oil pressure at high vehicle speeds to increase the reaction force transmitted to the steering wheel side, making the power steering characteristics heavier (higher rigidity) at high vehicle speeds.

Therefore, in order to obtain a high reaction oil pressure in a power steering system for a vehicle, a large negative force must be applied to the hydraulic pump, and the energy consumption becomes larger than when obtaining a low reaction oil pressure. Further, the time the vehicle travels at low speeds is extremely short compared to the time the vehicle travels at high speeds.

Considering this, in the conventional device described above, the power steering characteristics described above can be obtained while consuming a relatively large amount of energy.

The present invention has been made based on the above considerations,
The purpose is to provide a power steering device for a vehicle that can obtain the above-mentioned power steering characteristics with less energy consumption and can save energy.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a control valve that operates in accordance with the handle operating force to control the supply and discharge of pressure oil from the power cylinder, and a pusher that transmits a reaction force to the handle side. In a power steering device for a vehicle comprising a reaction force mechanism, the reaction force mechanism includes a spring biasing means that acts to elastically press the pusher to increase the reaction force, and a spring biasing means discharged from a hydraulic pump. a reaction oil pressure generation circuit that controls the hydraulic fluid generated according to the vehicle speed to generate a reaction oil pressure of high pressure at low vehicle speeds and low pressure at high vehicle speeds, and the reaction oil pressure supplied from the reaction oil pressure generation circuit. Accordingly, a reaction mechanism including a reaction oil chamber for applying a hydraulic pressure against the repulsive force of the spring biasing means to the presser element is adopted.

[Effect]

In the device according to the present invention, when the vehicle speed is low, high-pressure reaction oil pressure obtained from the reaction oil pressure generation circuit is supplied to the reaction oil chamber, and the pressing force from the reaction oil pressure is used as the elastic force by the spring biasing means. The reaction force that the pusher transmits to the handlebar side is reduced to a small value, and the power steering characteristics are light (low rigidity).

On the other hand, at high vehicle speeds, low-pressure reaction oil pressure obtained from the reaction oil pressure generation circuit is supplied to the reaction oil chamber, and the pressing force from the reaction oil pressure acts against the elastic force of the spring biasing means. The reaction force transmitted by the pusher to the steering wheel side is set to a larger value than at low vehicle speeds, and the power steering characteristics are made heavy (high rigidity).
shall be.

〔Effect of the invention〕

By the way, in the present invention, a high pressure reaction oil pressure that consumes a large amount of energy is obtained at low vehicle speeds, which account for a small proportion of the total running time, so that low rigidity power steering characteristics are obtained. At high vehicle speeds, which account for a large proportion of the vehicle's total driving time, it is possible to obtain low-pressure reaction oil pressure with low energy consumption, and to obtain highly rigid power steering characteristics. The total amount of energy consumed to obtain the optimal reaction force in the power steering device can be reduced compared to conventional systems, making it possible to save energy and improve the energy efficiency (fuel efficiency) of the vehicle. can be done.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2, a rack 10 is supported by a main body 12 via a rack guide 11 etc., and a steering link (
(not shown), and the pinion 13 is engaged. The pinion 13 is integrally formed with a pinion shaft 14, and the pinion shaft 14 has a pair of ball bearings 15, 16.
It is supported by the main body 12 via.

Each pole bearing 15.16 has a nut 17. They are fitted onto the pinion shafts 14 using snump rings 18 so as not to be movable in the axial direction, and one bearing 16 is installed parallel to the main body 12 along the rack 10, as shown in FIG. The outer race is assembled so as to be movable in the longitudinal direction (horizontal direction in FIG. 3) (in detail, the outer race can be moved) within the elongated hole 21.

Further, the pinion shaft 14 passes through the shaft seal 22 to the main body 12.
The parallel movement along the rack 10 (the first
It is designed to be linked with the handle F through a shaft joint (not shown) that allows movement in the left-right direction in FIGS. 23 is installed.

As shown in FIGS. 1 and 2, the displacement magnifying lever 23 is rotatably fitted onto the binion shaft 14 at an intermediate ring portion 24 via a needle bearing 25, and is rotatably fitted at a proximal spherical pivot portion 26. The support hole of the camp 27 fitted and fixed to the main body 12 is fitted within two days so that it can be tilted and moved in the axial direction, and the tip ball part 29 is fitted into the support hole 32 provided in the spool 31 so that it can be tilted and moved in the axial direction. It is fitted.

As shown in FIG. 1, the spool 31 has two annular grooves and is arranged in a direction perpendicular to the pinion shaft 14, and the spool 31 has a valve body 33 having three annular grooves.
Neutral spring 3 that urges 1 to the neutral position shown in the figure
4.35 and the like constitute a control valve V that controls the supply and discharge of pressure oil to the power cylinder C. Further, a hydraulic pump P, a power cylinder C, and a reservoir tank T are respectively connected to the valve body 33, and when the spool 31 moves to the right or left from the neutral position shown in FIG.
The direction of pressure oil supply to the power cylinder C is switched depending on the direction of movement.

However, in this embodiment, as shown in FIG.
The reaction force mechanism according to the present invention is integrally assembled with the control valve V described above. The reaction force mechanism includes a piston (pushing element) 36.37 that transmits a reaction force to the handle H side, and a reaction force that is formed between each piston 36.37 and each stepped portion 38.39 of the valve body 33 and communicates with each other. It is composed of oil chambers R1 and R2, a reaction oil pressure generating circuit A that generates reaction oil pressure to be supplied to both reaction oil chambers R1 and R2, and the like.

Each piston 36 , 37 is formed in an annular shape and is elastically pressed toward the spool 31 by each spring 34 , 35 .
It is configured to transmit the reaction force to the handle H side via No. 3 and the like. In addition, each screw I/N 36, 37 engages with each step provided at both ends of the spool 31 in the illustrated neutral state, and also engages with each step of the valve body 33, so that both reaction force oil The volumes of chambers R1 and R2 are minimized.

The reaction oil pressure generation circuit A generates a reaction oil pressure that is high pressure at low vehicle speeds and low pressure at high vehicle speeds (more specifically, it generates reaction oil pressure that decreases sequentially as the vehicle speed increases), and Valve (bypass type flow rate adjustment valve) 41. It is composed of an electromagnetic variable throttle valve 42, a fixed orifice 43, etc.

The diversion valve 41 is provided between the hydraulic pump P and the control valve 7, is known per se, and has a function of always allowing a portion (a small amount) of the hydraulic oil discharged from the hydraulic pump P to flow into the branch passage 44. have.

The electromagnetic variable throttle valve 42 is provided on the downstream side of the branch passage 44, and is configured to increase the throttle opening degree as the vehicle speed increases.

The fixed orifice 43 is interposed in a connection passage 47 that connects a passage 45 that connects the diversion valve 41 and the control valve V and a passage 46 that connects the branch passage 44 to both reaction oil chambers R1 and R2. , which is known per se, has a function of increasing the reaction oil pressure in accordance with the operation of the control valve V.

In this embodiment configured as described above, the pinion shaft 14 moves in parallel along the rack 10 within the elongated hole 21 during steering (moves in the left-right direction in FIGS. 1 and 3).
Accordingly, the displacement magnifying lever 23 swings to the right or left in FIG. let Therefore, the control valve V is operated to switch, and hydraulic assist is applied to the power cylinder C to assist the steering.

By the way, in this embodiment, a reaction force mechanism is integrally provided in the control valve V, and when the vehicle speed is low, the high pressure reaction oil pressure obtained from the reaction oil pressure generation circuit A is applied to both reaction oil chambers R1. ,R2
The pressure from the reaction hydraulic pressure is applied to each spring 3.
4.35, each piston 3
6.37 makes the reaction force transmitted to the handle H side via the spool 31 a small value, and makes the power steering characteristics light (low rigidity). On the other hand, at high vehicle speed, the low-pressure reaction oil pressure obtained from the reaction oil pressure generation circuit A is applied to both reaction oil chambers R1 and R.
2, the pressing force due to the reaction hydraulic pressure acts against the elastic force of each spring 34, 35, and reduces the reaction force that each piston 36, 37 transmits to the handle H side via the spool 3I. The value is large compared to the vehicle speed, and the power steering characteristics are heavy (high rigidity).

By the way, in this embodiment, a high pressure reaction oil pressure that consumes a large amount of energy is obtained at low vehicle speeds, which account for a small proportion of the total running time, so that low rigidity power steering characteristics are obtained. In addition, by making it possible to obtain a low pressure reaction oil pressure that consumes less energy at high vehicle speeds, which account for a large proportion of the total driving time, it is possible to obtain highly rigid power steering characteristics. The total amount of energy consumed to obtain the optimal reaction force in the power steering device can be reduced compared to conventional systems, making it possible to save energy and improve the energy efficiency (fuel efficiency) of the vehicle. can be done.

In the above embodiment, the present invention was described in Japanese Patent Publication No. 63-1511.
The neutral spring 34.35 is commonly used in the control valve of the vehicle power spring device proposed in Publication No. 33.
However, as shown in FIG.
The present invention can be similarly applied to a vehicle power spring device of the type proposed in Japanese Patent No. 573 (in which the pusher of the reaction force mechanism is configured separately from the control valve).

In the device shown in FIG. 4, the piston 1 of the reaction mechanism
36 and 137 are configured separately from the control valve V, and is substantially the same as the device of the above embodiment, so similar components will be given similar symbols and their explanation will be omitted.

In addition, the operation of this device is performed by the piston 136 of the reaction force mechanism,
137 to the handle H side (
In detail, this embodiment is substantially the same as the above embodiment except that the reaction force is transmitted to the steering shaft, so a description thereof will be omitted.

In each of the above embodiments, the fixed orifices 43, 143 were provided in the reaction hydraulic pressure generating circuit A so that the power steering characteristics changed according to the operation of the control valve (2). It is also possible to eliminate the fixed orifice.

Furthermore, in each of the above embodiments, a diversion valve 41.141 is interposed in the passage connecting the hydraulic pump P and the control valve V, and the pressure oil for obtaining the reaction hydraulic pressure is obtained from the diversion valve. , such pressure oil can be supplied from other hydraulic sources (e.g. other hydraulic pumps)
It is also possible to carry out the present invention by obtaining the following information.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of a power steering device for a vehicle according to the present invention, FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line ■■ in FIG. FIG. 4 is a schematic diagram showing another embodiment of the vehicle power steering device according to the present invention. Explanation of symbols 34.35, 134, 135... Spring (spring biasing means), 36.37, 136.137... Screw!・
(push element), A...reaction hydraulic pressure generating circuit, C...power cylinder, H...handle, P...hydraulic pump, ■...control valve, R1, R2...reverse Power oil room.

Claims (1)

[Claims] A power steering device for a vehicle comprising a control valve that operates in response to a steering wheel operating force to control the supply and discharge of pressure oil to a power cylinder, and a reaction force mechanism having a pusher that transmits a reaction force to the steering wheel side, The reaction force mechanism includes a spring biasing means that elastically presses the pusher to increase the reaction force, and a hydraulic fluid discharged from the hydraulic pump is controlled according to the vehicle speed to reduce the speed at low vehicle speeds. A reaction oil pressure generation circuit that generates a reaction oil pressure that is sometimes high pressure and low pressure when the vehicle speed is high; A power steering device for a vehicle, characterized in that it employs a reaction mechanism including a reaction oil chamber that applies hydraulic pressure to the pusher.