JPH11321679A - Oil pressure control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the various malfunction due to the influence of the chips adhered to each part while realizing the connection of a torsion bar and an input shaft to each other after the centering working without performing the mechanical working. SOLUTION: A connecting shaft 4c continuously provided to an end of a torsion bar 4 is inserted into a connection hole 2b formed in a core of an input shaft 2, and a constraining ring 5 is pressed into an annular clearance formed between the connecting shaft 4c and the connection hole 2b, and splines (projecting parts) formed in the inner and the outer peripheries of the constraining ring 5 are made to bite the connecting shaft 4c and the connection hole 2b so as to connect the torsion bar 4 and the input shaft 2 to each other in the condition that they can not be turned in relation to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a rotary hydraulic control valve used in a hydraulic power steering apparatus to control a hydraulic pressure supplied to a hydraulic actuator for assisting steering in accordance with a steering operation. .

[0002]

2. Description of the Related Art A hydraulic power steering device assists steering by a force generated by a hydraulic actuator such as a double-acting hydraulic cylinder (power cylinder) disposed in a steering mechanism of an automobile, and a steering wheel (steering wheel). ) To reduce the labor burden on the driver required for the operation, and to obtain a comfortable steering feeling. Both cylinder chambers of the power cylinder, a hydraulic pump as a hydraulic pressure source, and a A hydraulic control valve for controlling the supply and discharge of pressure oil in accordance with the direction and magnitude of the steering torque applied to the steering wheel is arranged between the oil tank and the oil tank.

[0003] As a hydraulic control valve for a power steering device, a rotary hydraulic control valve that directly uses the rotation of a steering wheel is widely used. The hydraulic control valve has a cylindrical valve body that coaxially connects an input shaft connected to a steering wheel and an output shaft connected to a steering mechanism via a torsion bar, and is engaged with one connection end of these two shafts. And a valve spool integrally formed on the outer periphery of the other connecting side is rotatably fitted to each other, and when a rotational torque for steering is applied to the steering wheel, the input shaft and the output shaft are caused by the torsion of the torsion bar. , Ie, between the valve spool and the valve body, a relative angular displacement corresponding to the rotational torque is generated.

[0004] A plurality of throttle portions for changing the throttle area in different directions according to the relative angular displacement are formed on the fitting periphery of the valve body and the valve spool. It is interposed between the source and the oil drain, respectively. The throttle portion has a throttle area equal to each other at a neutral position where the relative angular displacement does not occur. At this time, no pressure difference occurs between the two cylinder chambers of the power cylinder, and the power cylinder does not generate any force. .

On the other hand, when a rotational torque (steering torque) for steering is applied to the steering wheel, and a relative angular displacement occurs between the input shaft and the output shaft, that is, between the valve spool and the valve body. Then, the aperture area of the aperture portion arranged on the fitting circumference of the two changes. At this time, the pressure oil supplied from the hydraulic pressure source is introduced into one of the cylinder chambers of the power cylinder via the throttle portion having an increased throttle area, and a pressure difference is generated between the other cylinder chamber, The power cylinder generates an oil pressure corresponding to the pressure difference, and the oil pressure is applied to the steering mechanism as a steering assist force to assist the steering.

In the hydraulic control valve performing the above operation,
It is important that each of the plurality of throttle portions arranged on the fitting circumference of the valve body and the valve spool has an exactly equal throttle area at the neutral position. In assembling with the above, a centering operation for adjusting the circumferential position of both to determine the neutral position is performed as follows.

FIG. 5 is an explanatory view of a procedure for performing a centering operation which is generally performed in the related art. In the centering operation, the hollow input shaft 2 integrally formed with the valve spool 11 and the valve body 10 are used. An output shaft 3 engaged,
This is performed by temporarily assembling the torsion bar 4 connecting these components inside the test jig 6 corresponding to the housing.

The torsion bar 4 has large diameter portions 4a and 4b whose both ends are enlarged, and is inserted through the hollow portion of the input shaft 2. The large-diameter portion 4a having a serration formed on the outer circumference is press-fitted into a fitting hole 3a coaxially formed in the connection-side end of the output shaft 3 in the temporarily assembled state. The serration is engaged with the inner periphery of 3a to restrict rotation around the axis. The large-diameter portion 4b on the other side is relatively rotatably fitted in a fitting hole 2a of substantially the same diameter formed on the other end of the input shaft 2, and a suitable length from the shaft end of the input shaft 2. It is projected. Further, the valve body 10 is restrained in the circumferential direction by engaging an engagement groove 12 formed on one end surface thereof with a dowel pin 31 which is provided on the outer periphery of the output shaft 3.
The shaft is constrained in the axial direction by bringing the other end surface into contact with a retaining ring 32 wound around the outer periphery of the output shaft 3, and rotates integrally with the output shaft 3 while maintaining the axial position with respect to the valve spool 11.

The test jig 6 includes a pressure guide hole 60 corresponding to an oil supply hole from a hydraulic pressure source, pressure detection holes 61 and 62 corresponding to oil supply holes to both cylinder chambers of a hydraulic cylinder, Oil drain holes 64 communicating with each other are formed respectively, and the centering operation is
The input shaft 2 protruding outside the test jig 6 while monitoring the pressures P ₁ and P ₂ detected by the test holes 61 and 62 while introducing the test oil pressure P ₀ into the pressure guide hole 60. Is performed by rotating the shaft end portion as shown by the arrow in the figure. This operation is performed in a state where the large diameter portion 4b of the torsion bar 4 protruding from the shaft end of the input shaft 2 is gripped and the rotation of the output shaft 3 and the valve body 10 is restrained. The integrally formed valve spool 11 rotates relative to the inside of the valve body 10, so that the throttle area of the throttle portion arranged on the fitting circumference of the two changes, and a circumferential position where these throttle areas become equal (neutral position) When the position is obtained, the pressures P ₁ and P ₂ detected in the test holes 61 and 62 become equal.

As described above, the centering operation is performed by the input shaft 2
And the output shaft 3 are temporarily assembled in the test jig 6 without connecting the input shaft 2 and the torsion bar 4, and the rotation of the input shaft 2 causes the circumferential direction of the valve body 10 and the valve spool 11 to rotate. After adjusting the position to determine a circumferential position at which the difference between the pressures P ₁ and P ₂ detected at the test holes 61 and 62 becomes zero, remove the test jig 6 while maintaining the circumferential position. As shown by a broken line in the drawing, a pin hole 7a is formed near the shaft end of the input shaft 2 so as to penetrate with the large-diameter portion 4b of the torsion bar 4 fitted inside the input shaft 2. Dowel pin 7
To connect the large diameter portion 4b and the input shaft 2,
The neutral position is determined and the process is completed. The projecting portion of the large diameter portion 4b from the shaft end of the input shaft 2 is cut after the knock pin 7 is driven so as not to hinder the connection between the input shaft 2 and the steering wheel.

[0011]

However, in the conventional centering operation performed as described above, it is necessary to drill a knock hole 7a for driving the knock pin 7, and chips generated by the drilling are generated. It is unavoidable that the input shaft 2 adheres to the outer peripheral surface of the input shaft 2 over a wide range, and the input shaft 2 and the output shaft 3 connected via the torsion bar 4 by driving the knock pin 7 are incorporated into a housing (not shown) to be commercialized. In such a hydraulic control valve, there is a problem that the cutting chips intervene in a fitting portion between the valve body 10 and the valve spool 11 to hinder the hydraulic control operation, and are used to seal the inside and outside of the housing. There is a problem in that the cutting chips intervene in a sliding portion between the sealing member and the input shaft 2 and this sealing is impaired.

Therefore, in the conventional hydraulic control valve, after a knock hole 7a for driving the knock pin 7 is formed,
The operation of removing the chips attached to the outer peripheral surface of the input shaft 2 is indispensable, and this causes a problem that an unnecessary increase in the number of steps is caused. Further, even when the above-described removal operation is performed, There is a problem that the above-mentioned inconvenience caused by the attachment of the chips cannot be completely eliminated, and the occurrence of defective products with reduced hydraulic control operation or sealing performance is inevitable.

The present invention has been made in view of the above circumstances, and realizes connection between an input shaft and a torsion bar after centering work without using mechanical processing, and eliminates inconvenience caused by the attachment of chips. It is an object of the present invention to provide a hydraulic control valve which can be operated.

[0014]

A hydraulic control valve according to the present invention is configured between an input shaft and an output shaft coaxially connected via a torsion bar, and a rotational torque applied to the input shaft. A hydraulic control valve that controls the supply and discharge of pressure oil in accordance with the relative angular displacement caused by the twisting of the torsion bar between the input shaft and the output shaft. A connection shaft formed in the torsion bar, and a connection shaft that is provided at one end of the torsion bar and fits with an annular gap inside the connection hole, and is press-fitted into the gap,
A constraining ring for engaging the convex portion formed on the inner and outer peripheries of the connecting shaft and the inner perimeter of the connecting hole respectively so as to restrain the connecting shaft and the connecting hole from rotating is provided. It is characterized by.

In the present invention, a connecting shaft connected to one end of the torsion bar which is connected to the input shaft is fitted inside a connecting hole formed at a corresponding position of the input shaft.
After the centering work is performed in this state, a constraining ring having a convex portion such as a spline is press-fitted into an annular gap formed in the fitting portion, and a convex portion on the inner peripheral side of the restricting ring. Are respectively engaged with the outer peripheral surface of the connection shaft, and the convex portion on the outer peripheral side is also engaged with the inner peripheral surface of the connection hole, so that the connection shaft and the connection hole, that is, the input shaft and the torsion bar are relatively non-rotatably connected.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing the embodiments. FIG. 1 is a longitudinal sectional view showing a configuration example of a hydraulic control valve according to the present invention applied to a power steering device.

In the hydraulic control valve according to the present invention, a hollow input shaft 2 connected to a steering wheel and an output shaft 3 connected to a steering mechanism are coaxially connected via a torsion bar 4 inserted through a hollow portion of the input shaft 2. And these are rotatably supported around the same axis in a cylindrical housing H, and the output shaft 3
A cylindrical valve body 10 rotatably held around an axis inside the housing H is attached to the connection side end of the housing H so as to be integrally rotatable, and the valve body 10 is attached to the connection side outer periphery of the input shaft 2. And is rotatably fitted to the outside of a valve spool 11 formed integrally with the valve spool 11.

The valve body 10 is constrained in the circumferential direction by engaging a notch groove 12 formed on one end surface of the valve body 10 with a dowel pin 31 formed on the outer peripheral surface of the output shaft 3. The other end surface is brought into contact with a retaining ring 32 wound around the input shaft 2, and is constrained in the axial direction to maintain coaxiality with the valve spool 11 integrally formed with the input shaft 2 and the output shaft 3 while maintaining the axial position. It is designed to rotate together.

A torsion bar 4 for connecting the input shaft 2 and the output shaft 3 is provided on both sides of a main body having an outer diameter and a length in order to obtain desired torsional characteristics, with a large-diameter portion having a larger diameter. Four
a, 4b are connected in series. The large-diameter portion 4a on one side has serrations formed over the entire outer peripheral surface thereof,
The serration is pressed into a fitting hole 3a formed at an axial center position of the upper end surface of the output shaft 3 while biting the serration. The rotation of the shaft is restrained by the action of the serration, and the output shaft 3 is coaxial. Are linked together.

A large-diameter portion 4b on the other side of the torsion bar 4 has an O-hole wound halfway around a fitting hole 2a formed by reducing the diameter of the hollow portion of the input shaft 2 on the side protruding outside the housing H.
The ring 40 is coaxially fitted in a liquid-tight manner.

A connecting shaft 4c having a smaller diameter than that of the large diameter portion 4b is coaxially connected to the distal end of the large diameter portion 4b. This connecting shaft 4c
Is located coaxially inside a connection hole 2b formed by increasing the diameter of the fitting hole 2a on the shaft end side of the input shaft 2,
The torsion bar 4 and the input shaft 2 are connected via a restraining ring 5 which is press-fitted into an annular gap formed between the connecting shaft 4c and the connecting hole 2b.

FIG. 2 is an enlarged view of the vicinity of the connecting portion between the torsion bar 4 and the input shaft 2, and FIG. The restraining ring 5 for connecting the torsion bar 4 and the input shaft 2 has an inner diameter slightly smaller than the outer diameter of the connecting shaft 4c and an outer diameter slightly larger than the inner diameter of the connecting hole 2b.
As shown in FIG. 3, each of the inner and outer peripheral surfaces is a short annular ring having splines (projections) formed thereon, and is made of a material having a higher hardness than the torsion bar 4 and the input shaft 2.

The connecting shaft 4c at the tip of the torsion bar 4 is located coaxially inside a connecting hole 2b formed at the shaft end of the input shaft 2, and forms an annular gap with the connecting hole 2b. doing. As shown by the arrow in FIG. 3, the constraining ring 5 has an inner spline on the outer peripheral surface of the connecting shaft 4c and an outer spline on the outer peripheral surface of the connecting shaft 4c in an annular gap formed between the connecting shaft 4c and the connecting hole 2b. The splines are press-fitted while being bitten into the inner peripheral surface of the connection hole 2b, respectively, and are interposed between the connection shaft 4c and the connection hole 2b as shown in FIG. Has made.

The connecting shaft 4c is connected to a large diameter portion 4b of the torsion bar 4, and the large diameter portion 4b is connected to the connection hole 2b.
And is fitted inside a fitting hole 2a provided in the axial center portion of the input shaft 2 so as to be continuous with the inside. Therefore, when press-fitting the constraining ring 5 performed as described above, the connecting shaft meshed with the inner and outer circumferences of the constraining ring 5.
The coaxiality between 4c and the connection hole 2b is not impaired, and the torsion bar 4 and the input shaft 2 are connected coaxially while their relative rotation is restricted.

The input shaft 2 and the output shaft 3 connected via the torsion bar 4 as described above are connected to the torsion bar 4 in accordance with the rotational torque applied to the input shaft 2 by operating the steering wheel.
Relative angular displacement with the twist of Input shaft 2
The outer peripheral surface of the valve spool 11 integrally formed with the valve body 10 and the valve body 10 engaged with the output shaft 3, that is, the outer peripheral surface of the former and the inner peripheral surface of the latter are extended in the axial direction. A plurality of oil grooves are juxtaposed in the circumferential direction so as to be substantially equally arranged, and they are staggered in the circumferential direction on the fitting circumference, and are arranged between adjacent oil grooves in accordance with the relative angular displacement. Thus, a plurality of aperture portions for changing the aperture area are formed.

A hydraulic pump P serving as an oil supply source has a pump port 20 penetrating the housing H in and out and a valve body 10.
And an oil groove (distribution groove) adjacent to both sides of the oil groove through an oil supply hole penetrating through the valve body 10. The oil cylinder is connected to both cylinder chambers S _L and S _R of the power cylinder to which the oil is to be fed via respective oil ports and the other cylinder ports 21 and 22 penetrating the housing H inside and outside. Further, an oil groove (oil drain groove) adjacent to the other side of the distribution groove communicates with an oil drain chamber 23 formed on one side of the valve body 10 through a hollow portion of the input shaft 2, and At a corresponding position in the oil chamber 23, the oil chamber 23 is communicated with an oil tank T through which a housing H passes through the inside and outside of the housing H.

The plurality of throttle portions arranged on the fitting circumference of the valve body 10 and the valve spool 11 have equal throttle areas in a neutral state in which the torsion bar 4 is not twisted by a centering operation performed as described later. Adjusted to have. Therefore, when no rotational torque is applied to the input shaft 2, the pressure oil supplied from the hydraulic pump P to the oil supply groove via the pump port 20 is uniformly introduced into the distribution grooves adjacent on both sides, and furthermore, Is introduced into the oil drain groove adjacent to the other side, and the hollow portion of the input shaft 2, the oil drain chamber 23,
And the oil is discharged to the oil tank T via the tank port 24. At this time, the cylinder chambers S _L and _{L L} communicated with the distribution grooves, respectively.
Pressure difference between S _R not occur, the power cylinder is not generated any force.

On the other hand, when a rotational torque (steering torque) for steering is applied to the steering wheel, the steering wheel is moved between the input shaft 2 and the output shaft 3, that is, between the valve spool 11 and the valve body 10. A relative angular displacement is generated in the direction of the steering torque with the torsion of the torsion bar 4, and the aperture area of the aperture portion arranged on the fitting circumference of the two changes. At this time, the pressure oil supplied to the oil supply groove is mainly introduced into one of the distribution grooves through the restriction portion on the side with the increased restriction area, and the cylinder port 21 (or 22) is connected to the distribution groove. Between one cylinder chamber S _L (or S _R ) communicated with the other cylinder chamber S _R (or S _L ) communicated with the other distribution groove via the cylinder port 22 (or 21). Creates a pressure differential,
The power cylinder generates a hydraulic pressure corresponding to the pressure difference, and the hydraulic pressure is applied to the steering mechanism as a steering assist force to assist the steering.

At this time, the other cylinder chamber S _R (or S
_L ) hydraulic fluid is pushed out from the corresponding cylinder port
The liquid flows back to the other distribution groove via 22 (or 21), and is introduced into the oil drain groove through a throttle portion having an increased throttle area on one side of the distribution groove, and the hollow portion of the input shaft 2 and the oil drain chamber 23, and tank port
After passing through 24, it is discharged to the oil tank T. During the operation described above, the hollow portion of the input shaft 2 serving as a passage for draining oil to the oil tank T is an O-ring wound around the large-diameter portion 4b of the torsion bar 4.
Since the oil is sealed in a liquid-tight manner by 40, there is no possibility that the drainage oil leaks to the outside.

In order to stably operate the hydraulic control valve as described above, in a neutral state where the torsion bar 4 is not twisted, a plurality of hydraulic control valves arranged on the fitting periphery of the valve body 10 and the valve spool 11 are arranged. It is essential to perform a centering operation of adjusting the circumferential positions of the two throttle portions so that the narrow portions have the same throttle area.

In the hydraulic control valve according to the present invention, the input shaft 2 and the torsion bar 4 are connected via a restraining ring 5 press-fitted from the shaft end of the input shaft 2.
In the state before the pressure is press-fitted, the input shaft 2 and the torsion bar 4 are relatively rotated to form a valve spool 11 integrally formed on the input shaft 2 and a valve body 10 engaged with the output shaft 3. The position can be adjusted in the circumferential direction, and the centering operation is performed using this.

FIG. 4 is an explanatory diagram of a procedure for performing a centering operation in the hydraulic control valve of the present invention. This centering operation is performed, similarly to the conventional centering operation shown in FIG. 5, by connecting the input shaft 2 integrally formed with the valve spool 11 and the output shaft 3 engaged with the valve body 10 to the housing H.
In the test jig 6 corresponding to the above, the input shaft 2 and the torsion bar 4 are temporarily assembled in a state where they are not connected, and the oil drain hole 64 corresponding to the tank port 24 is connected to the oil drain destination,
Iris diaphragm portion which while introducing a hydraulic pressure P ₀ for test oil groove through the pressure guide hole 60 corresponding to the pump port 20 are relatively rotated the valve body 10 and the valve spool 11 aligned on the fitting circumference of both The procedure is performed by adjusting the area and determining a circumferential position (neutral position) at which the difference between the pressures P ₁ and P ₂ taken out from the pressure detection holes 61 and 62 corresponding to the cylinder ports 21 and 22 becomes zero.

In the tentatively assembled state shown in the drawing, a connecting shaft 4c provided on the torsion bar 4 for connection with the input shaft 2 includes:
A grip 4d having a further reduced diameter at the distal end is continuously provided, and protrudes from the shaft end of the input shaft 2 by an appropriate length. The relative rotation between the valve body 10 and the valve spool 11 in the centering operation is performed by gripping the grip portion 4d and restraining the rotation of the output shaft 3 and the valve body 10 via the torsion bar 4, as shown in FIG. The operation is performed by rotating the input shaft 2 as indicated by a symbol.

In the centering operation of the hydraulic control valve according to the present invention, the rotation operation of the input shaft 2 as described above is performed by using the pressure detection holes 61 and 62.
While monitoring the pressures P ₁ and P ₂ taken out at the same time, after determining a circumferential position (neutral position) where these differential pressures become zero, the circumferential position is maintained, and the connecting shaft 4c and the connecting hole 2b are maintained. As described above, the constraining ring 5 having splines on the inner and outer circumferences is press-fitted into the annular gap between the outer peripheral surface of the connecting shaft 4c and the connecting hole 2b.
The torsion bar 4 and the input shaft 2 are connected to each other by engaging the inner peripheral surfaces of the torsion bars, and the neutral position is determined to complete the operation.
The grip 4c protruding from the shaft end of the input shaft 2 is cut off after the completion of the centering operation.

Next, the thus obtained input shaft 2
The hydraulic control valve as shown in FIG. 1 is formed by removing the connected body of the output shaft 3 and the test jig 6 from the test jig 6 and incorporating it inside the housing H. In the hydraulic control valve configured as described above, the connection between the torsion bar 4 and the input shaft 2 for determining the neutral position is realized without press-fitting the restraining ring 5 and without machining. Chips intervene in the fitting portion between the valve body 10 and the valve spool 11 to hinder the relative angular displacement of the two, and there is no risk that the supply / discharge operation of the pressure oil as described above will be hindered. H
For example, there is no possibility that chips may intervene in the sliding portion between the oil seal 8 (see FIG. 1) for sealing the inside and the outside and the input shaft 2 and the sealing by the oil seal 8 may be damaged. It is possible to avoid various inconveniences caused by the action of the generated chips.

The restraining ring 5 is connected to a connecting shaft on the side of the torsion bar 4 by engagement of splines formed on the inner and outer circumferences.
4c and the connection hole 2b on the input shaft 2 side, the connection between the torsion bar 4 and the input shaft 2 is firmly realized without any positional displacement in the circumferential direction. Is secured by the fitting portion between the large-diameter portion 4b and the fitting hole 2a on one side of the connection shaft 4c and the connection hole 2b.

In the above embodiment, the constraint ring 5 having a spline as a convex portion on the inner and outer circumferences is used. However, the convex portion is not limited to the spline, but may have serrations or irregular protrusions. The convex portion may be formed by a separate member such as a ball embedded in the inner and outer circumferences of the constraint ring 5. Further, in the above-described embodiment, an example of application to a power steering device has been described. However, the application range of the present invention is not limited to this, and is applicable to a rotary hydraulic control valve for controlling supply and discharge of pressure oil. It is needless to say that the application of is possible.

[0038]

As described in detail above, in the hydraulic control valve according to the present invention, the connecting shaft connected to one side of the torsion bar is fitted into the inside of the connecting hole formed in the input shaft. Since the constraining ring is press-fitted into the annular gap, and the convex portions formed on the inner and outer peripheries of the constraining ring are engaged with the connecting shaft and the connecting hole, the connection between the input shaft and the torsion bar after the centering operation is completed. Strongly realized without machining,
The present invention can eliminate various inconveniences due to the influence of cuttings generated by machining, significantly reduce the occurrence rate of defective products, defective sealing products, and improve the product yield. It has excellent effects.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a configuration example of a hydraulic control valve according to the present invention applied to a power steering device.

FIG. 2 is an enlarged view of the vicinity of a connecting portion between a torsion bar and an input shaft.

FIG. 3 is an explanatory view of a mounting procedure of a restraining ring.

FIG. 4 is an explanatory diagram of an execution procedure of a centering operation in the hydraulic control valve of the present invention.

FIG. 5 is an explanatory diagram of a procedure for performing a centering operation in a conventional hydraulic control valve.

[Description of Signs] 2 Input shaft 2b Connection hole 3 Output shaft 4 Torsion bar 4c Connection shaft 5 Retaining ring 10 Valve body 11 Valve spool

Claims (1)

[Claims] 1. An input shaft and an output shaft which are coaxially connected via a torsion bar and which are configured to rotate between the input shaft and the output shaft by the action of a rotating torque applied to the input shaft. A hydraulic control valve for controlling the supply and discharge of pressure oil in accordance with a relative angular displacement generated due to the torsion of the torsion bar between the connecting hole formed in the shaft portion of the input shaft and one of the torsion bars. A connection shaft that is connected to the side end and fits with an annular gap inside the connection hole, and a protrusion that is press-fitted into the gap and formed on the inner and outer circumferences with the outer circumference of the connection shaft. A hydraulic control valve, comprising: a restraining ring which is engaged with an inner periphery of the connecting hole so as to restrain the connecting shaft and the connecting hole from rotating.