JPS61155061A - Steering power control unit for power steering device - Google Patents

Abstract

PURPOSE:To improve a direct feeling by providing a reaction force control means that controls pressure actuated on the pressure chamber of a reaction force mechanism based on the signals of a handle steering angle in addition to the control of the steering power that corresponds to the car speed. CONSTITUTION:A power steering device is provided with a servo valve 30 that controls the supply and exhaust of pressurized oil into a power cylinder according to the relative rotation between an input shaft 23 as the steering shaft and an output shaft 21 as the pinion shaft 23 as the steering shaft and an output shaft 21 as the pinion shaft 23 as the steering shaft and an output shaft 21 as the pinion shaft. In addition, the device is provided with a reaction force mechanism including a moving plunger 54 in the radial direction, that introduces the pressurized oil exhausted from a supply pump 60 and passing through first and second flowrate control valves 61 and 65 operated so as to constantly keep the pressure before and behind metering orifices 62 and 66, from an introduction port 58 and is varied into the handle torque corresponding to the car speed and such. In this case, the introduction port 58 can be connected to a reservoir through a pressure control valve 70 and the pressure control valve 70 can be controlled based on the signals of the handle steering angle.

Description

[Detailed Description of the Invention] <Industrial Field of Application> The present invention provides control pressure according to vehicle speed, etc.! The present invention relates to a steering force control device for a power steering device equipped with a reaction force machine S which supplies a steering torque Z and changes it according to vehicle speed, etc.

<Prior Art> It is known that a control pressure proportional to the vehicle speed or the like is introduced into a reaction force mechanism to control the steering force of the power steering device according to the vehicle speed or the like. After this kind of power steering [GX.

Supplying and discharging pressure oil to the power cylinder? Generally, the servo valve components to be controlled are flexibly connected to the input shaft and the output shaft via a Y-version.

<Problems to be Solved by the Invention> Nowadays, users are required to improve the direct feeling of steering in a power steering device, so it is necessary to increase the rigidity of the steering gear. To achieve this, by increasing the spring constant of the torsion bar,
The valve detection angle becomes small, the neutral pressure increases, and the processing is very difficult. Therefore, even with a structure that includes a torsion bar, there is a limit to the spring constant, making it difficult to meet the requirements.

The present invention utilizes a reaction force mechanism χ that controls the steering angle of a power steering device to increase the gear rigidity commensurate with the rigidity of the torsion bar, thereby improving the direct feeling Y.

<problem? Means for Solving> The present invention provides a servo valve that is operated based on relative rotation between an input shaft and an output shaft to control supply and discharge of pressure oil to a power cylinder, and a pump that is controlled according to vehicle speed, etc. In a steering force control device for a power steering device equipped with a reaction force mechanism Y that introduces pressure oil and changes the steering torque according to vehicle speed, etc., the input shaft and the output shaft are held relatively rotatably, A reaction force control means Z is provided which applies a hydraulic pressure commensurate with the rigidity of the torsion bar or its insufficiency when the steering wheel is in a neutral state, and changes the hydraulic pressure as the steering angle changes. It consists of

Function> The above-mentioned present invention controls the control pressure applied to the reaction force chamber of the reaction force mechanism according to the vehicle speed, and also adjusts the hydraulic pressure commensurate with the stiffness of the torsion bar or the lack thereof based on the steering angle of the steering wheel. The gear rigidity can be arbitrarily set to a large value using a reaction force mechanism.

<Example> Hereinafter, an example of the present invention will be described based on the drawings. In FIG. 1, reference numeral 11 indicates a housing main body χ of the power steering device, and reference numeral 12 indicates a valve housing fixed to the housing main body 11. As shown in FIG. A pinion shaft (output shaft) 21 is rotatably supported in the housing body 11 and the valve housing 12 via a pair of bearings 13.14''k, and a pinion shaft 21 is slidable in a direction crossing the pinion shaft 21. Rack teeth nα of a movable rack axis are in mesh with each other.This rack shaft 22 is connected to a piston of a power cylinder (not shown), and both ends thereof are connected to steering wheels via a required steering link mechanism. There is.

The large circle of the valve housing 12 accommodates a control valve mechanism. The control valve mechanism (servo valve) 30 includes a rotary valve member 31 integrally formed with an input shaft n as a steering shaft;
A sleeve valve member 32a' is a main component that fits concentrically and relatively rotatably around the outer periphery of the rotary valve member 31. The rotary valve member 31 is supported by the pinion shaft 21 via a bearing 91 so as to be relatively rotatable. Further, a plurality of lands and grooves (not shown) extending in the axial direction are formed at equal intervals on the outer periphery of the rotary valve member 31, and a communication path 37 is formed in which the bottom of the groove communicates with the inner circumference. is drilled. A passage 39 is provided in the input shaft B, which communicates the inner peripheral portion with the low pressure chamber in the valve housing 12. On the other hand, a plurality of lands and grooves extending in the axial direction are formed at equal intervals on the inner circumference of the sleeve valve member 32, and distribution holes 40, 41 are provided that open from each groove to the outer circumference of the sleeve valve member 32. ing. When the control valve is in the neutral state, the pressure fluid supplied from the supply boat 35 flows evenly into the grooves on both sides of the land portion, and flows through the communication passage 37 and the passage 3.
After 9 hours, it flows out from the low pressure chamber 38 to the exhaust port 36. In this case, the power cylinders cannot be operated because both distribution boats 33 and 34 are at low and equal pressure. If the control valve deviates from the neutral state, one distribution hole
The fluid discharged from the power cylinder flows into and is discharged to the discharge boat I through the communication passage a, the passage 39, and the low pressure chamber 387a'.

The reaction force mechanism is as follows. As shown in FIG. 2, protrusions (2) protruding from both sides in the radial direction are formed at the end of the rotary valve member 31 on the pinion shaft 21 side. A fitting groove 51 is formed to be loosely fitted around the axis of the 50'Y input shaft B so as to be rotatable through several angles. A tapered engagement groove 52 is formed on the outer peripheral surface between the protrusions, and when the control valve is in a neutral state, an insertion groove is formed in the pinion shaft 21 in the radial direction at a position corresponding to the engagement groove 52. ing. A plunger leg is slidably inserted in the insertion hole 53 in the radial direction, and an annular groove is formed to guide hydraulic oil to the rear part of the plunger leg. The insertion hole 53 and the annular groove define a reaction force chamber. 58
is a passage communicating with an annular groove 55Y, a boat 57 (worker's boat) 58 through which pressure fluid is introduced under controlled pressure from a pump controlled according to vehicle speed, etc.

The reaction force mechanism configured as described above is of a so-called radial type, but may also be a thrust type configured to apply a reaction force in the axial direction.

Reference numeral 60 indicates a supply pump driven by an automobile engine, and the discharge boat of this supply pump ω is connected to the supply boat through a first flow control valve 61. The flow rate control valve 61 is operated according to a metering orifice 62 provided in a passage connecting the discharge boat of the supply pump (a) and the supply boat, and the pressure before and after this metering orifice 62. In order to keep the pressure constant at all times, the supply boat 35 is configured with a bypass passage 63 '5: a bypass valve which controls the opening of the valve, and a constant flow rate necessary for the power steering device is supplied to the supply boat 35 by this flow rate control valve 61. excess flow is bypassed to the bypass passage 63. Bypass passage 63 of first flow control valve 61
Second flow control valve 65? The introduction boat between the reaction force chambers is connected to the swamp via. Such second flow control valve 6
5 is a metering orifice 6 provided in the passage 46 which is connected to the bypass passage 63 and the introduction bow 58.
6, and a bypass valve 68 that is operated according to the longitudinal pressure of this metering orifice 66 and controls the opening of a bypass passage 67 connected to the reservoir so as to keep this longitudinal pressure constant. The flow 1tya introduced into the introduction boat enclosure by the flow control valve 65 of No. 2
- constant control and bypassing of the surplus flow to the reservoir via the bypass passage 67; The introduction boat 58 is connected to the reservoir via a pressure control valve 70Yf, which will be described later.

Next, what is the configuration of the pressure control valve 70? The pressure control valve 70 (engineering), which will be explained based on FIG. The spool 74, the valve seat member 76 formed with a relief passage 71' communicating with the introduction bow 58, and the relief passage 75'f of the valve seat member 76! : Consists of a ball valve 77 that opens and closes, a relief pressure setting spring 78 and a balance spring 79 inserted between the ball valve 77 and the movable spool 74. The movable spool 74 usually has springs 78,7
9 is maintained in the state shown in the figure, and the spring load Z of the relief pressure setting spring 78 is set to the maximum thickness. However, as the movable spool 74 is displaced to the right against the balance spring 79 due to the suction action of the solenoid 73, the spring load of the spring 78 is reduced. The solenoid B has a solenoid drive circuit 8 controlled by a computer.
1 to vehicle speed signal V and steering wheel steering angle e() - rigidity of the steering wheel? A current value corresponding to the input signal taken into consideration is supplied, and the control pressure (relief pressure) PC changes according to this current value.

In this case, it may be an electromagnetic control valve that changes the variable aperture area Z according to the supplied current value.

Further, the means for supplying control pressure to the reaction force mechanism is not limited to the double flow rate control valve system as in the above embodiment, but may also be a 70-divider system or the like.

Next, the operation in the above configuration will be explained.

The pressure oil discharged from the supply pump 60 is controlled to a predetermined flow rate by a first flow control valve 61, and is supplied to the supply bow 35 of the power steering device. At the same time, the first flow control valve 61
The surplus flow is controlled to a constant flow rate by the second flow control valve 65 and drained into the reservoir via the pressure control valve 70χ. When the vehicle speed is low, the maximum current is supplied to the solenoid 73 of the pressure control valve 70, so that the spring load of the relief pressure setting spring 78 becomes substantially 0, and the control pressure PC & pressure is maintained at 0. Therefore, when the steering shaft is rotated by operating the handle, the plunger 5
The sleeve valve member 32 and the rotor valve member 31 are thereby rotated relative to each other, and a normal power steering action is performed.

When the vehicle speed exceeds a predetermined value, the computer 8 (1: solenoid drive circuit & is controlled according to the input vehicle speed signal V, and the current value supplied to the solenoid '73 of the pressure control valve 70 is adjusted according to the increase in vehicle speed. As a result, the spring load of the relief pressure setting spring 78 increases as the vehicle speed increases, and as a result, the control pressure PC introduced into the reaction force chamber 56 via the introduction boat 58 increases as the vehicle speed increases. In response to this, the plunger 54 is pressed against the engagement groove 52 with a force corresponding to the X control pressure, and the manual torque for relative rotation of the valve member 32 and the rotor valve member 31 is increased.

In addition to controlling the steering force according to the vehicle speed as described above, the present invention also provides a pressure control valve 7 based on the signal of the steering wheel steering angle ρ.
The control pressure applied between the reaction force chambers of the reaction force mechanism is controlled by 0, and as shown by the solid line in Fig. 4, the hydraulic reaction force PCg is shown by the dotted line. The reaction force is controlled by switching. As a result, when the steering wheel is in the neutral position, the gear generation pressure Pk shown in the fifth factor is increased (the gear rigidity is thickened (shifted state)), and the necessary gear rigidity can be obtained without a torsion bar and the gear can be adjusted at low and high speeds. The manual torque can be changed by selecting Hg.Moreover,
Gear rigidity when the steering wheel is in neutral? The magnitude of the determined hydraulic reaction force PC can be set arbitrarily and thickly by changing the current applied to the solenoid 73 of the pressure control valve 7o.

Nao, in the above embodiment, the torsion bar t is omitted and the rigidity corresponding to the torsion bar is controlled by reaction force, but the invention is not limited to this, and if a torsion bar with a weak spring constant is used, Hydraulic pressure to compensate for this lack of spring constant with 7 reaction force control? Control. J: You may set it to 5.

<Effects of the Invention> As described above, the present invention can adjust the hand torque depending on the vehicle speed. The control pressure introduced into the reaction force chamber is controlled based on the steering angle of the steering wheel behind the machine that changes the reaction force, and the hydraulic reaction force is arbitrarily thickened (by adjusting the gear rigidity corresponding to the torsion bar rigidity or the torsion bar). It is possible to compensate for the lack of gear rigidity and increase the gear rigidity, and the gear rigidity at minute angles can be set arbitrarily thick.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a power steering device showing an embodiment of the present invention, with a hydraulic system diagram drawn over it, Fig. 2 is an enlarged sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is a diagram showing the working pressure Main part sectional view of control valve, No. 4
The figure is a diagram showing hydraulic reaction force characteristics, and FIG. 5 is a diagram showing gear generated pressure characteristics. 21...Fist pinion shaft, 2311...Input shaft, 3011
・Number control valve mechanism, secretion...reaction force chamber, ω...supply pump, 70...pressure control valve.

Claims (1)

[Claims] A servo valve operates based on the relative rotation of the input shaft and output shaft to control the supply and discharge of pressure oil to the power cylinder, and a pump controls the pressure oil according to the vehicle speed, etc. by introducing pressure oil from the pump. In a steering force control device for a power steering device, the input shaft and the output shaft are connected and supported so as to be relatively rotatable, and the control pressure introduced into the reaction force mechanism is stopped. A steering force control device for a power steering device, comprising a reaction force control means that generates sufficient pressure to maintain an input shaft in the neutral state when the steering wheel is in the neutral state, and changes the hydraulic pressure as the steering angle changes.