JPS6354592B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power steering device, and more particularly to a power steering device in which a control valve for controlling the supply and discharge of pressure fluid to and from a power cylinder is of a rotary type.

A rotary control valve usually has a valve rotor that is integrally provided on the input shaft on the steering wheel side, and an output shaft on the steering wheel side that can rotate around the outer circumference of the valve rotor. When the valve sleeve is operated, the power is generated depending on the direction of the relative rotational displacement from the neutral state caused between the input shaft and the output shaft, that is, between the valve rotor and the valve sleeve. Controls the supply and discharge direction of pressure fluid to and from the cylinder. Conventionally, the input shaft and the output shaft are connected via a torsion bar, and the torsion force of the torsion bar allows the valve rotor and the valve sleeve to be maintained in a neutral state when the valve is not in operation. However, in the torsion bar,
Due to its structure, the valve rotor and valve sleeve must be in a neutral state when the left and right torsional force is zero, and therefore it is impossible to apply preload between the input and output shafts with the torsion bar. .

For this reason, conventionally, in addition to or in place of the torsion bar, a C-shaped spring is used, for example, a link-shaped spring material is partially cut out to form a roughly C-shape.
A protrusion that is integral to the input shaft and a protrusion that is integral to the output shaft are simultaneously held between the notches of the C-shaped spring with a predetermined elastic force, thereby maintaining both shafts in a neutral state and at the same time providing a preload. A power steering device has been proposed that allows this.

However, when sandwiching the pair of protrusions with the C-shaped spring, it is necessary to place each protrusion in advance at a predetermined position with extremely high precision with respect to the valve rotor or valve sleeve, and in the unlikely event that manufacturing errors etc. If one of the protrusions is misaligned in the circumferential direction, the valve rotor and valve sleeve will be assembled with the valve rotor and valve sleeve deviated from their normal neutral position when both protrusions are held between the C-shaped springs. Become. Since it is generally difficult to correct the positional deviation of the protrusion, conventionally, if the amount of deviation exceeds a certain tolerance range, it has been discarded, which is extremely wasteful.

Therefore, the applicant proposed that when a circumferential deviation occurs between a pair of engaging parts such as a pair of protrusions, if both engaging parts are held in the misaligned state by a spring, the control valve becomes neutral. Focusing on the ability to secure the position, a power steering device has been proposed in which a small modification is made to the spring and the modified spring holds both engaging portions in a shifted state. It is an object of the present invention to provide a method and device for detecting the amount of deviation.

The present invention focuses on the fact that when the input shaft is rotated to change the relative position of a pair of control valve elements, the pressure of the fluid supplied to the control valve changes, and the pressure value is minimized. It was confirmed through experiments that the pair of control valve elements are in the neutral state position when and detecting the neutral state position of the pair of control valve elements from the minimum value of the fluctuation of fluid pressure supplied to the control valve due to rotation of the input shaft;
The amount of deviation in the circumferential direction between the two engaging portions is detected from the amount of relative rotational displacement at this neutral state position.

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

In FIG. 1, the input shaft 1 and the output shaft 2 are arranged on the same axis, and the protrusion 3 protruding from the tip shaft of the input shaft 1 is fitted into the distal shaft of the output shaft 2. In this state, the input shaft 1 and the output shaft 2 are rotatably supported in the housing 5 via bearings 6a and 6b. The input shaft 1 is linked to a steering handle (not shown), and a helical pinion 7 is formed at the tip of the output shaft 2. It is easily engaged with the steering wheels that do not operate.

As shown in FIGS. 1 to 4, a roughly rectangular engagement portion 8 is provided at the tip of the input shaft 1 in front of the protrusion 3, and the output shaft 2 receives the engagement portion 8. A groove 9 is formed, and the engaging portion 8 is disposed within the groove 9 with a required gap in the circumferential direction. Therefore, the input shaft 1 and the output shaft 2 are
The gap allows for relative rotation by an amount allowed. Protrusions 10 and 11 are provided in the vicinity of the engagement portion 8, that is, the input shaft 1, and the groove 9, that is, the output shaft 2, respectively.
The engagement portions 12a and 12b of the C-shaped spring 12 are sandwiched between the end faces of the C-shaped spring 12 disposed on the outer periphery of the groove 9.

At this time, the circumferential spacing l between the engaging portions 12a and 12b of the C-shaped spring 12 in the natural state (see FIG. 2) is set smaller than the length of each protrusion 10 and 11 in the same direction, Therefore, by sandwiching both the protrusions 10 and 11 with this C-shaped spring 12, a desired preload can be applied between the input and output shafts 1 and 2. And again, C
The pair of engaging portions 12a and 12b of the shaped spring 12
are formed to be slightly shifted in the circumferential direction, and the amount of deviation L is between the valve rotor 13 and the valve sleeve 1.
The amount of deviation in the circumferential direction between the protrusions 10 and 11 is made to correspond to the amount of deviation in the circumferential direction when the protrusions 10 and 11 are accurately placed in the neutral position. That is, the pair of engaging portions 12a, 12
b corresponds to the amount of deviation in the circumferential direction between the protrusions 10 and 11 when the valve rotor 13 and the valve sleeve 14 are accurately placed in the neutral position, which is measured by the detection method described later. Therefore, if both protrusions 10 and 11 are held between the engaging portions 12a and 12b having the bias amount L, the valve rotor 13 and the valve sleeve 14 will be separated. is accurately maintained in a neutral state when no external force is acting on the input/output shafts 1 and 2. In this state, the engaging portion 8 is held at approximately the center position of the groove 9 in the circumferential direction.

However, the valve rotor 1 is connected directly to the input shaft 1.
3 is formed, and a valve sleeve 14 is rotatably fitted around the outer periphery of the valve rotor 13, basically forming a conventionally known rotary type control valve. The end portion of the valve sleeve 14 on the output shaft 2 side is formed as a cylindrical portion 14a that can be fitted into the portion 2a of the output shaft 2 provided with the protrusion 11, and the protrusion 11 is attached to the cylindrical portion 14a in the circumferential direction. An axial engagement groove 15 having a width that matches the width, and a through hole 16 that allows the protrusion 10 to pass therethrough and allows the protrusion 10 to be displaced in the circumferential direction are formed. The cylindrical portion 14a is located inside the C-shaped spring 12 as shown in FIGS. The projections 10 are integrally connected in the rotational direction, and the protrusion 10 loosely fits through the through hole 16 with a required spacing at least in the rotational direction. The C-shaped spring 12 is held between a spacer 17 provided on the stepped portion 2b of the output shaft and the stepped portion 14b of the valve sleeve 14.

In the neutral state, the control valve composed of the valve rotor 13 and the valve sleeve 14 simply circulates the pressure fluid (oil) from the pump 18 shown in FIG. 6. That is, the pressurized fluid from the pump 18 is channeled through a supply hole 20 formed in the housing 5, an annular groove 21 formed in the valve sleeve 14, and a radial passage 2, as shown in FIGS. 1, 5, and 6.
2 into the axial supply groove 23 formed in the valve rotor 13, and axial grooves 24, 25 formed on the inner surface of the valve sleeve 14 so as to be able to overlap on both sides of the groove 23 in the circumferential direction; Both grooves 24, 25
It flows into an axial exhaust groove 26 formed in the valve rotor 13 so that it can polymerize. The pressure fluid that has flowed into the discharge groove 26 flows along the groove toward the abutting portion between the input shaft 1 and the output shaft 2, and from there flows into the through hole 16 and the engaging portion 1 of the C-shaped spring 12.
2a and 12b to the outer periphery of the valve sleeve 14, and is further discharged into the oil tank 19 through a discharge hole 27 provided in the housing 5, and then returned to the suction side of the pump 18. Groove 2 on one side of the supply groove 23
4 communicates with one chamber of a power cylinder (not shown) through a radial passage 28, an annular groove 29, and a supply/discharge hole 30 provided in the housing 5, and similarly, the groove 25 on the other side also communicates with a radial passage 31, an annular groove. 32 and the supply/discharge hole 33 to the other chamber of the power cylinder, but in the neutral state, the respective flow path areas of the supply groove 23 and the grooves 24 and 25 on both sides thereof are substantially equal; Since there is no pressure difference between the grooves 24 and 25, the power cylinder remains inactive.

On the other hand, when the input shaft 1 is rotated in one direction, both protrusions 10,
According to the interval between 11 and 11, the valve rotor 13 and the valve sleeve 1
When a relative rotation occurs between the supply grooves 23 and the grooves 24 and 25 on both sides of the supply groove 23 and the grooves 24 and 25 on both sides of the supply groove 23 and the flow path area differs depending on the direction of rotation.
A pressure difference occurs between the two. As a result, both grooves 2
4 and 25 are operated to apply an auxiliary force in the steering direction as is well known in the art. At this time, due to the pressure difference generated between the two grooves 24 and 25, the pressure fluid supplied from the pump 18 to the supply hole 20 is also regulated by the fluid pressure of the higher one of the pressure differences and rises. Therefore, the pressure of the pressure fluid supplied from the pump 18 to the supply hole 20 exhibits the lowest value when the control valve is in the neutral state.

FIG. 6 shows a device for detecting the amount of deviation L according to the present invention, which will be explained below.

The power steering device has its output shaft 2 mounted on a fixing jig 35.
The supply and discharge holes 30, 3
3 is disposed in a closed state by a closing plate 36, and a shaft 38 of a reversible motor 37 is connected to its input shaft 1. A signal from a computer 39, which will be described later, is input to the reversible motor 37 via a sequence circuit 40 and a motor drive circuit 41, so that the reversible motor 37 is driven in forward and reverse directions. A torque sensor 42 for detecting the input torque T and an angle sensor 43 for detecting the input angle θ are attached to the shaft 38 of the motor 37, and a pressure fluid line connecting the pump 18 and the supply hole 20 includes:
A hydraulic sensor 44 for detecting the hydraulic pressure P is provided. And each of these sensors 42, 43, 44
Accordingly, the input torque T, the input angle θ, and the oil pressure P are each actually measured. Each of these actual measured values is input to and stored in the computer 39 as a digital signal via amplification circuits 45, 46, 47 and A/D converters 48, 49, 50, respectively. Amplification circuits 45, 46,
The output signal from 47 is also input as an analog signal to the display 51 as shown in the figure, and the relationship between input torque T and oil pressure P and the relationship between input angle θ and oil pressure P are displayed as graphs. ing.

The calculator 39 is formed of a mini-computer having a memory function, a comparison function, and an arithmetic function, and receives actual measured values from the A/D converters 48, 49, and 50 as well as a reference signal input device 52. A reference signal is input and stored. This reference signal includes a control signal 53 that controls the reversible motor 37 so that the rotation angle β ₁ of the input shaft 1 satisfies -β ₁ < θ < β ₁ , and a control signal 53 that controls the reversible motor 37 so that the deflection angle Δθ satisfies -α < Δθ < α. The deviation angle tolerance signal 54 to be set, the preset torque ΔT must be less than or equal to t ₂ and t ₁
Preset torque tolerance signal 5 to be set above
5, and a groove width signal 56 for setting a reference C-shaped spring groove width h.

These reference values are compared with the actual measured values and calculated in the calculator 39, and the output from the calculator 39 is converted into the C-shaped spring 12 as a groove machining position correction signal 57 and a groove width correction signal 58 of the C-shaped spring 12. The information is input to an NC machine 59 that processes the spring 12. The output from the calculator 39 is also displayed on the display 6.
0 and 61, respectively, and are displayed as a deviation angle correction display and a groove width correction display.

Next, a method for detecting the amount of deviation will be explained.

When the reversible motor 37 is rotationally driven based on the control signal 53, the input shaft 1 is rotationally driven, and its input torque T and input angle θ are determined by the torque sensor 4.
2 and angle sensor 43.
On the other hand, when the input shaft 1 rotates, the oil pressure supplied from the pump 18 to the supply hole 20 fluctuates, and the value is actually measured by the oil pressure sensor 44. These actual measured values are input to the display 51 and displayed in analog form, and are also input to the computer 39 where they are compared with the signal from the reference signal input device 52 and calculated.

First, the input torque T is compared and calculated with the preset torque allowable range signal 55 and the groove width signal 56, and if it is within the allowable range, the groove width correction signal 58 is not outputted from the calculator 39. Therefore,
The groove width correction display is not displayed on the display 61 either. On the other hand, if the input torque T is outside the allowable range, a correction value for the reference C-shaped spring groove width h is output from the calculator 39 as a groove width correction signal 58.
At the same time as being input to the NC machine 59,
The output from 9 is also input to the display 61 to display groove width correction. The NC machine 59 performs numerical control based on the input groove width correction signal 58, and processes the corrected C-shaped spring 12.

On the other hand, the input angle θ is calculated by the calculator 39 along with the oil pressure P.
The signal is inputted to and compared with the deviation angle tolerance signal 54 and calculated. If the input angle θ when the oil pressure P shows the lowest value is within the allowable range, the calculator 3
9 does not output the groove processing position correction signal 57. Therefore, the deviation angle correction display is not displayed on the display 60 either. On the other hand, if the input angle θ is outside the allowable range, the amount of deviation of the protrusions 10 and 11 from the relative non-operating position is outputted from the computer 39 as a groove machining position correction signal 57, and the NC machine 59, the output from the calculator 39 is also input to a display 60 to display the deviation angle correction. The NC machine 59 performs numerical control based on the input groove processing position correction signal 57, and processes the corrected C-shaped spring 12.

The C-shaped spring 12 that has been corrected by the NC machine 59 that is numerically controlled based on the correction signals 57 and 58 is replaced with the C-shaped spring 12 that is attached to the power steering device. .

In this way, since the C-shaped spring is modified based on the correction data for correcting the hydraulic characteristics, it is possible to easily assemble a power steering device that has no deviation in hydraulic characteristics and has an optimal preload. Become.

Although FIG. 6 describes the case where both the input torque T and the input angle θ are measured, the torque sensor 42 and the like may be omitted and only the deviation angle Δθ may be detected.

The present invention has been described above based on preferred embodiments, but according to the present invention, the amount of deviation in the circumferential direction between both engaging portions is detected based on the pressure fluctuation of the pressure fluid supplied to the control valve. Therefore, the detection is accurate and easy, and by modifying the spring based on the amount of bias, it is possible to easily assemble a power steering device without deviation in the fluid pressure characteristics of the pressure fluid.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an example of a power steering device according to the present invention, FIG. 2 is an exploded perspective view of the main parts of FIG. 1, and FIG. 3 is a sectional view taken along the - line in FIG. 4 is a view taken in the direction of arrow A in FIG. 3, FIG. 5 is a sectional view taken along the line -- in FIG. 1, and FIG. 6 is a block diagram showing one embodiment of the present invention. 1: input shaft, 2: output shaft, 10, 11: protrusion,
12: C-shaped spring, 12a, 12b: engaging portion, 1
3: Valve rotor, 14: Valve sleeve, 37: Reversible motor, 39: Computer, 43: Angle sensor, 4
4: Oil pressure sensor, 57: Grooving position correction signal, 5
9: NC machine, L: deviation amount, θ: input angle, P:
Hydraulic pressure, Δθ: deflection angle.

Claims (1)

[Scope of Claims] 1. An input shaft linked to a steering wheel, an output shaft disposed on the same axis as the input shaft and linked to steering wheels, and a pair of controls provided on each of the two shafts. A rotary control valve that is composed of valve elements and controls the supply and discharge of pressure fluid to the power cylinder according to the relative rotational displacement of both control valve elements, and an engaging portion that is integrally provided on each control valve element. and a spring that engages and urges both the engaging parts to hold both the engaging parts in a predetermined relative non-operating position, and each engaging part of the spring to each of the engaging parts is connected to the engaging part of the spring. When shifting the pair of control valve elements in the circumferential direction by an amount corresponding to the amount of deviation in the circumferential direction from the above-mentioned relative non-operating position between the two engaging parts when the pair of control valve elements are in the normal neutral state position, the above-mentioned input The shaft is rotated relative to the output shaft to detect the amount of relative rotational displacement of both engaging parts from the relative non-operating position, and the input shaft of the pressurized fluid supplied to the control valve is rotated. detecting the neutral state position of the pair of control valve elements from the minimum value of pressure fluctuation accompanying the neutral state position, and detecting the amount of deviation in the circumferential direction between the two engaging parts from the relative rotational displacement amount at this neutral state position. A method for detecting the amount of deviation from a neutral position in a power steering device, characterized by: 2. An input shaft linked to the steering wheel, an output shaft disposed on the same axis as the input shaft and linked to the steering wheel, and a pair of control valve elements provided on each of the two shafts. A rotary type control valve that controls the supply and discharge of pressure fluid to the power cylinder according to the relative rotational displacement of the control valve elements, an engaging portion provided integrally with each control valve element, and both engaging portions. a spring that engages and biases the engaging portions to hold the engaging portions in a predetermined relative non-operating position; When shifting the input shaft in the circumferential direction by an amount corresponding to the amount of deviation in the circumferential direction from the above-mentioned relative non-operating position between both engaging parts when the normal neutral state position is set, the input shaft is shifted relative to the output shaft. The amount of relative rotational displacement of both engaging parts from the relative non-operating position is detected by rotating the input shaft relative to each other, and the pressure fluctuation due to the rotation of the input shaft of the pressurized fluid supplied to the control valve is detected. A neutral state in a power steering device in which a neutral state position of a pair of control valve elements is detected from the minimum value of A deviation amount detection device from a position, the detection device includes a motor that rotates the input shaft relative to the output shaft, an angle sensor that detects the rotation angle of the input shaft by this motor, and the a pressure fluid supply source that supplies pressure fluid to the control valve;
A power source comprising: a pressure sensor that detects pressure fluctuations caused by rotation of an input shaft of pressurized fluid supplied to the control valve; and a computer that inputs signals from the angle sensor and the pressure sensor. A device for detecting the amount of deviation from a neutral position in a steering gear.