JPS62258864A - Steering power control device for power steering device - Google Patents

Abstract

PURPOSE:To obtain a characteristic curve giving the smaller inclination with the larger steering angle by providing a non-linear type compression spring in a distribution control valve. CONSTITUTION:A steering power control device comprises a pressurized oil supply source 80, a reaction mechanism 10, a servo valve 20, a distribution control valve 40, a valve device 50 and a power cylinder 90. And the distribution control valve 40 has an inlet port 41 for receiving said oil, a primary outlet port 43 for supplying said oil to a servo valve side passage and a secondary outlet port 45 for supplying said oil to the reaction mechanism 10. And an unequal pitch spring 48 is provided for energizing a spool 47 to a direction for opening the secondary outlet port 45, and the inlet port 41 and the secondary outlet port 45 are made continuous to each other via an orifice 451 formed on the spool 47.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a steering force i, +1 m Vtδ of a power steering device that hydraulically controls a power cylinder of a power steering.

[Conventional technology]

Steering force 11 of a conventional power steering V4 position that controls the reaction force that changes the rotational force of the steering wheel according to vehicle speed etc.
60g1 is operated based on the relative rotation between the input shaft and the output shaft, and supplies and discharges pressure oil to the power cylinder.
A servo valve that controls I, a reaction force IHT that changes handle torque depending on medium speed, etc., and a constant flow of pressure oil discharged from a supply pump are connected to a servo valve side passage and a reaction force mechanism side passage l\flow suspension. It is composed of a diversion control valve that divides the flow by controlling the servo valve side and a fixed throttle valve that connects the servo valve side passage and the reaction force mechanism side passage.

This fixed throttle valve increases the pressure oil in the pressure mechanism side passage by moving a part of the pressure oil from the servo valve side passage to the reaction mechanism side passage in response to the increase in the generated pressure that contributes to steering wheel assist. This is provided to control the reaction force pressure in accordance with the gear generated pressure. In this way, when driving at high speeds, the slope of the characteristic is made smaller, and as the steering angle of the steering wheel (hereinafter referred to as steering angle) increases, a greater actuation force is required.
A steering force control device including a fixed throttle valve has been proposed to increase the steering force of the steering wheel.

Further, a cylindrical coil spring is used in the flow control valve. Therefore, the characteristics of the conventional branch 1Ill Iff valve are as shown in FIGS. 8 to 11. 8th
1 and 10 are characteristic diagrams showing the relationship between gear pressure, reaction force flow, and reaction force pressure using vehicle speed as a parameter when using a fixed throttle valve, respectively.

9 and 11 are characteristic diagrams showing the relationship between gear pressure, reaction flow M, and reaction pressure, respectively, using vehicle speed as a parameter when there is no fixed throttle valve.

[Problems to be Solved by the Invention] However, although satisfactory steering characteristics can be obtained by providing a fixed throttle valve, a so-called throttle noise is generated when fluid passes through the fixed throttle valve. This squeeze sound is
This is an unpleasant sound for vehicle occupants and is an inevitable result of oil passing through an orifice at high speed.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a steering force control device for a power steering device in which the unpleasant noise is not generated and the operating characteristics are not impaired.

[Means for Solving the Problems 1] The steering force 1+1 steering device of the power steering device of the present invention is operated based on the relative rotation between the input shaft and the output shaft, and supplies and discharges pressure oil to and from the power cylinder using 41+ A servo valve that changes if, a reaction force mechanism that changes steering torque depending on vehicle speed, etc.
A flow control valve that controls the flow rate and divides the pressure oil of a constant gt m discharged from the supply pump into the servo valve side passage and the reaction force mechanism side passage; In the steering force control device 11 of a power steering device, which includes a valve device 5 for controlling reaction pressure oil pressure, the branch tIlIII valve has an inlet port that receives pressure oil;
a first outlet port that supplies pressure oil to the servo valve side passage;
a second outlet port that supplies pressure oil to the reaction mechanism through an orifice; a spool that opens and closes the first outlet port and the second outlet port in opposite directions; and a spool that opens and closes the second outlet port in a direction that closes the second outlet port. a pressure chamber that biases the spool;
It is characterized by a configuration consisting of nonlinear compression springs such as unequal pitch springs and conical coil springs that bias the spool in the direction of listening to the outlet port.

That is, the steering force ill-lit device of the power steering device of the present invention includes a servo valve, a reaction force mechanism, a branch control valve, and a valve device.

The steering force control device for a power steering device of the present invention is characterized in that it has a branch control valve that supplies pressure oil to an inlet port that receives pressure oil and to the servo valve side passage. a first outlet port that supplies pressurized oil to the reaction force mechanism through an orifice; a spool that opens and closes the first outlet port and the second outlet port in opposite directions; Consists of a pressure chamber that biases the spool in the direction of closing the second outlet port, and a nonlinear compression spring such as an unequal pitch spring or a conical coil spring that biases the spool in the direction of opening the second outlet port. It is.

In other words, the springs attached to the diverter f and II Iff valves are nonlinear compression springs, as opposed to conventional cylindrical coil springs. By doing this,
If the distance between movements of the spool that moves according to the steering angle increases, the load required to generate unit deflection increases. This makes it possible to obtain the same smoothness as the effect of the fixed throttle valve in the conventional device. In other words, in the device of the present invention, a characteristic curve whose slope becomes gentler as the steering angle becomes larger can be obtained without providing an identified throttle valve.

The parts of the Iff valve other than the nonlinear compression spring, the servo valve, the reaction force mechanism, and the valve device can be used as conventional ones or with some modifications.

[Function] In the steering force & 11 sin device of the power steering device of the present invention, the second
The coil spring that biases the spool in the direction of opening the outlet port is composed of a nonlinear compression spring such as an unequal bidge spring or a conical coil spring. Therefore, when the gear generation pressure increases, the spool of the diversion υ1111 valve is displaced in the direction of closing the second outlet port against the resistance from the nonlinear compression spring, but the amount of displacement increases for the same load, and the degree of this displacement is The spring constant increases as the spring constant increases. Therefore, the flow rate diverted from the second outlet port to the reaction force mechanism side passage increases, and the reaction force pressure is reduced in accordance with the gear generation pressure.

[Example] Hereinafter, the steering force control m+ device of the power steering device of the present invention will be described based on specific examples.

This embodiment is applied to a power steering system in an automatic vehicle, and as shown in FIG. 1, the hydraulic circuit diagram of the entire embodiment is as follows: It mainly consists of a reaction force 11ffl110, a 20% diversion control valve 40, a valve device 50, and a power steering device having a power cylinder 90 connected to the device of the present invention. The branch control valve 40, which is a feature of the present invention, is connected to the high pressure side of the pressure oil supply source 80, and the spool 47 is slid by the differential pressure in front of the orifice, which will be described later, and the spring 48, and the spool 47 is slid by the servo valve 20 side passage 20.
1, and also to the reaction force chamber side passage 101. That is, the branch control valve 40 has an inlet port 41 that receives pressure oil, a first outlet port 43 that supplies pressure oil to the servo valve side passage, and a second outlet port 45 that supplies pressure oil to the reaction mechanism 10. , a spool 47 for opening and closing the first outlet port 43 and the second outlet port 1-45 in opposite directions; It is composed of a pressure chamber 49 and an unequal spring 48 whose outer shape is shown in FIG. 3 or FIG.
and the second outlet port 45 are communicated via an orifice 451 formed in the spool 47.

The servo valve 20 is a conventional valve used as is, and is housed in the valve housing 112 of the power steering bag M100. This servo valve 20 includes a rotary valve member 21 integrally formed with an input shaft 123 as a steering shaft;
It is mainly composed of a sleeve valve member 22 fitted to the outer periphery of the 0-tally valve member 21 so as to be concentric and relatively rotatable. This rotary valve member 21 is flexibly connected to a binion shaft 121 via a torsion bar 124 whose one end is connected to an input shaft 123 integrated therewith. Although not shown, on the outer periphery of the rotary valve member 21,
A plurality of land portions and groove portions extending in the axial direction are formed at intervals of M, and a communication passage 27 communicating from the bottom of the groove to the inner peripheral portion is bored. A hole l' is provided in the input shaft 123 to communicate the inner circumference with the low pressure chamber 28 in the valve housing 112.
829 is provided. On the other hand, on the inner periphery of the sleeve valve member 22, land portions extending in the respective axial directions and grooves are formed at equal intervals, and distribution holes 1110 are formed from each groove portion to the outer periphery of the sleeve valve member 22. , 141 are provided. When the servo valve 20 is in the neutral state, the pressure fluid supplied from the supply port 25 flows equally into the grooves on both sides of the land portion, and flows out from the low pressure chamber 28 to the discharge port 26 via the communication passage 27 and the passage 29. In this case, the first hydraulic passage 42
, both distribution ports 23.2 discharging into the second hydraulic passage 44.
Since pressure 4 is low and equal, the power cylinder 90 does not operate. When the servo valve 20 is displaced from the neutral state, one distribution hole 140 or 141 has the supply port 2.
Pressure oil is supplied from 5, and the other distribution hole 141 or 140
The fluid discharged from the power cylinder 90 flows into the discharge port 2 through the communication passage 27, two passages, and the low pressure ff28.
It is designed to be released on the 6th.

The power steering Si mushroom 100 is a so-called rack and pinion type steering device and has a reaction force n structure, and has a housing main body 111.
, and a valve housing 112 fixed to a housing body 111.

This power steering Wi 100 has this housing main body 111
and a pinion shaft (output shaft) 121 rotatably supported by a pair of bearings 113 and 114 in the valve housing 112;
It has a rack shaft 122 having rack teeth 222 that mesh with this pinion shaft 121. This rack shaft 122 is
It is connected to the piston of the power cylinder 90.

The reaction force mechanism generates its function by a reaction force chamber.

The reaction force chamber 155 is composed of an insertion hole 153 and an annular groove 159, as shown in FIG. 3 in a cross section taken along the cutting line AA in FIG. In other words, this reaction force 1 is generated by the protrusion 150 formed on the end of the rotary valve member 21 on the side of the binion shaft 121 so as to protrude on both sides in the radial direction.
Then, the pinion shaft 121 corresponding to this protrusion 150 can be turned several angles around the axis of the input shaft 123 3! A fitting groove 151 formed to fit i2 and a plunger 15
4 is slidably inserted into the 1ITI through hole 153, a plunger 154, and an annular groove 159 for guiding hydraulic fluid to the rear of the plunger 154.

Note that the port 157 is a port that introduces pressure fluid from a pump that is controlled according to vehicle speed, etc., and the passage 158 is a passage that communicates this port 157 with the annular groove 155.

That is, the reaction mechanism 10 includes the plunger 154 and the rack shaft 12.
This plunger 154 is connected to the valve 12! from the second output port of the diverter valve 40 to generate a mechanical reaction force with the valve 12!
It is activated by the pressure oil flowing through f50.

The reaction force increases as the pressure of this pressure oil increases.

The valve device 50 is for returning pressure oil from the pump 81 and the second output port 45 of the diverter valve 40 to the reservoir, and is constituted by a near solenoid valve 50 which is approximately proportional to the applied current.

The pressure oil supply source 80 includes a supply pump 81 driven by an automobile engine, a flow control valve 83 that controls the pressure oil discharged from the supply pump 81 to a constant flow rate, and a fixed compensating valve 8.
It consists of 5.

In the embodiment configured in this way, the flow rate υl11
The pressure oil discharged from the supply pump 81 is controlled to have a constant flow rate by the 11 valve 83 and the valve system ff150.

The pressure oil subjected to this constant flow is the servo valve 20, the valve system r! ! 50. The action of the oil flowing into the servo valve 20 is similar to the action of the slave valve ξ, so a description thereof will be omitted.

When the vehicle speed is low, the near solenoid valve 50 is fully open due to the applied current applied to the solenoid. Therefore, the pressure oil diverted from the second outlet port 45 to the reaction mechanism side passage flows from the valve device 50 to the reservoir without resistance. Therefore, no back pressure is generated on the inlet side of the valve device 50, and no acting force is generated on the screw 1 hem 54 of the reaction force mechanism. In other words, since the reaction oil pressure is maintained at zero, when the input shaft 123 is rotated 101 times by operating the handle, the plunger 1r154
is easily pushed down, thereby causing the sleeve valve member 22
The rotary valve member 21 and the rotary valve member 21 can be easily rotated relative to each other, and the change in the gear generation pressure PG with respect to the manual torque has the characteristics shown by the low speed, stationary curve 301 in FIG. 12, allowing light steering operation.

Further, when the vehicle speed exceeds a predetermined value, the opening degree of the linear solenoid valve 50 becomes smaller in accordance with the neutral force zero current applied to the solenoid. As a result, the amount returned to the reservoir is ν
j is limited, and the reaction oil pressure is upper bound.

The plunger 154 is pressed against the protrusion 150 by the upper limit of the reaction pressure corresponding to the upper limit of the heavy speed, and as a result, the relative rotation between the sleeve valve member 22 and the rotary valve member 21 is restricted, making it difficult to operate the handle. .

On the other hand, when driving at high speed, if the handle is turned in, the spool 47 opens the second output port in response to the increase in the gear pressure generated on the servo valve 20 side! As the amount of movement increases, the spring load increases as shown by the solid line in FIG. 6 because a nonlinear compression spring is used. This increases the differential pressure before and after the Lio orifice, increasing the flow rate of pressure oil diverted to the second outlet port, and the reaction oil pressure increases in accordance with the increase in gear generation pressure, resulting in load pressure sensitivity. It will be done. In other words, a large operating force is required to increase the amount of rotation of the steering wheel.

Its counterpart is the high-speed song in Figure 12! ! Like J302,
The slope of the manual torque characteristic is changed to a greater extent than the conventional characteristic in accordance with the gear generation pressure PG, making it clearer to feel the response when turning the steering wheel at high speed.

According to this embodiment, in the steering force υJilt device of the power steering device δ, the shunt control valve is connected to the inlet ports 1 to 1 which receive pressure oil.
and a first outlet port that supplies pressure oil to the servo valve side passage;
a second outlet port that supplies pressurized oil to the reaction mechanism through an orifice; a spool that opens and closes the first outlet port and the second outlet port in opposite directions; and a spool that opens and closes the second outlet port. a pressure chamber that urges the spool in the second direction;
It is composed of non-linear compression springs such as unequal pitch springs and conical coil springs that bias the spool in the direction of opening the exit port, so there is no need to provide a fixed orifice (although the effect of these non-compression springs allows the steering angle to change The reaction force pressure is controlled to increase accordingly.

Further, there is no squeezing noise, and the configuration of the steering force 13111 device can be simplified.

[Effects of the Invention] According to the present invention, the steering force of the auxiliary steering device is connected to the inlet port for receiving pressure oil and the servo valve +
A first outlet port that supplies pressure oil to the 111 passage, a second outlet port that supplies pressure oil to the reaction mechanism through an orifice, and the first outlet port and the second outlet port are arranged in opposite directions. a spool that opens and closes; a pressure chamber that biases the spool in a direction to close the second outlet port; and an uneven pitch spring that biases the spool in a direction to open the second outlet port;
By using a non-linear compression spring such as a conical coil spring, the reaction force pressure is non-linearly controlled according to the steering angle. Due to the +L and deflection characteristics of the nonlinear compression spring, as the steering angle increases, the reaction force of the reaction force mechanism increases, and a larger operating force is required to rotate the steering wheel than before. The operating characteristics of the device can be obtained. Moreover, since no fixed throttle valve is used, there is no throttle noise.

[Brief explanation of drawings]

FIG. 1 is a hydraulic circuit diagram of a steering device having a steering force control device for an auxiliary steering device according to a specific embodiment of the present invention. FIG. 2 is a central sectional view showing the internal structure of the hydraulic 1i7J exchange valve, and FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2. FIGS. 4 and 5 are external views of the springs used in the same embodiment. FIG. 6 and FIG. 7 are characteristic diagrams showing the relationship between deflection and load, gear pressure, gear flow rate, and reaction pressure used in the same embodiment, respectively. 8 to 11 are characteristic diagrams showing the relationship between gear A2 pressure, reaction force outflow, and reaction force pressure using vehicle speed as a parameter. FIG. 12 is a characteristic diagram showing the steering characteristics. 10...Reaction force n 15i 20...→J~
Bo valve 40... Diversion control 11 valve 50... Valve device 41... Inlet port 43... First outlet port 45... Second outlet port 47... Spool 48...
...Nonlinear compression spring patent applicant Toyota Machinery Co., Ltd. agent Patent attorney Okawa Momo Patent attorney Akio Maruyama Figure 3 Figure 4 Figure 5 Figure 7 Tasomi PG

Claims (1)

[Claims] (1) A servo valve that is activated 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, a reaction force mechanism that changes the steering wheel torque according to vehicle speed, etc., and a supply pump. a flow control valve that controls the flow rate and divides a constant flow of pressure oil discharged from the servo valve side passage and the reaction force mechanism side passage; In a steering force control device for a power steering device that includes a valve device that controls hydraulic pressure, the branch control valve has an inlet port that receives pressure oil and a first outlet that supplies pressure oil to the servo valve side passage. a second outlet port that supplies pressure oil to the reaction mechanism through an orifice; a spool that opens and closes the first outlet port and the second outlet port in opposite directions; It is characterized by a configuration consisting of a pressure chamber that biases the spool in the closing direction, and a nonlinear compression spring such as an unequal pitch spring or a conical coil spring that biases the spool in the direction that opens the second outlet port. A steering force control device for a power steering device.