JP3278752B2 - Valve chamfering method for rotary valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary valve suitable for use as a rotary flow path switching valve in a hydraulic power steering apparatus for reducing the steering force of a steering wheel of an automobile, for example, and more particularly to a rotary valve relative to a sleeve. The present invention relates to a method for processing a valve chamfer in a passage groove in a rotor that distributes and controls a fluid pressure by an appropriate rotational displacement.

[0002]

2. Description of the Related Art This type of rotary valve is a flow path switching valve for operating a power cylinder, which is a movable part, in a power steering apparatus or the like in accordance with a steering operation to generate a steering assist force during a steering operation. And the like, conventionally, JP-A-57-178971, Japanese Utility Model Publication No. 63-30613
Various proposals have been made, such as Japanese Patent Publication No.

That is, the rotary valve for switching the flow path is provided with an input shaft (stub shaft) connected to the steering handle.
And a sleeve integrally provided on the output shaft (pinion shaft) on the steered wheel side and a sleeve integrally provided on the steering wheel side in a state where they can be relatively rotated and displaced. A plurality of passage grooves formed in the circumferential direction at the outer peripheral portion of the rotor and the inner peripheral portion of the sleeve,
The simple structure of connecting the passages communicating with the left and right cylinder chambers constituting the oil pump, oil tank, and power cylinder, which are the fluid pressure generation sources, makes it easy and appropriate to switch the flow path of the fluid pressure circuit (hydraulic circuit). I can do it.

[0004]

By the way, in the above-described rotary valve, chamfering at a groove side edge of a passage groove formed at a predetermined interval in a circumferential direction on an outer peripheral portion of the rotor has conventionally been performed by a work. It was performed using the axis of the rotor as the center as a processing reference.

[0005] However, the outer peripheral portion of such a rotor may have a fluctuating outer diameter due to deformation problems occurring during pre-processing or heat treatment of the outer peripheral portion of the rotor. If chamfering is performed on the outer peripheral portion of the rotor having different dimensions using the axis as the processing reference, the processing position and the processing amount, particularly the chamfer cutting depth, vary. If the chamfer processing accuracy varies, the chamfer shape, especially the chamfer formed in each portion in the circumferential direction of the rotor, varies, and the overlap angle of the chamfer fluctuates. It was difficult to obtain good characteristics when performing the test.

For example, in a rotary valve used as a rotary flow path switching valve in a power steering device,
The flow path is switched depending on the communication between the passage grooves of the rotor and the sleeve disposed around the rotor, and the cutoff state. However, since the chamfer shape, particularly the overlap angle, varies, an appropriate flow control characteristic is obtained. It was difficult.

[0007] In particular, in the rotary valve described above,
In order to obtain desired valve characteristics, a clearance between the outer diameter of the rotor and the inner diameter of the sleeve which is a mating member,
It is important to manage the underlap angle in the neutral state and the overlap angle in the steering state based on the chamfering accuracy (angle) of the rotor, and it is desired to take some measures that can solve the above-mentioned problems.

In the above-described rotary valve,
Conventionally, when performing chamfering on the groove side edges on both sides of a plurality of passage grooves formed on the outer peripheral portion of the rotor,
One of a plurality of passage grooves in the outer peripheral portion of the rotor or a serration whose relative angle is determined with respect to the passage groove or a positioning plate provided in engagement with the serration,
A positioning means such as a lateral locator pin or an engaging element is jumped in for positioning, the rotor is clamped by a chuck in this positioning state, and the above-described one passage groove is used as a processing reference, and a grindstone or other cutting means is used for each passage. It has been common practice to sequentially perform chamfering on the groove side edges on both sides of the groove.

Here, after the chamfering in one passage groove is completed, the chuck is removed to release the clamped state, the rotor is rotated by a predetermined angle in this state, and then the chuck is again used. Clamping is performed, and chamfering is performed in the next passage groove by using the above-mentioned grindstone or the like, and similar processing is performed a required number of times thereafter.

However, the plurality of passage grooves formed in the outer peripheral portion of the rotary valve of the rotary valve by pre-processing are as follows.
In practice, the grooves are often formed with a positional deviation from the groove forming positions evenly arranged in the circumferential direction of the rotor due to the processing of the grooves and the processing accuracy, and as a result, as described above, one passage groove is formed. If the center of the groove is measured, and the rotor is sequentially rotated using this as a processing reference, and chamfering is performed on both side edges of each passage groove, the following problems cannot be avoided.

That is, in such a conventional method, the chamfer of the reference groove can be formed relatively accurately.
If there is a deviation in the groove formation position on the outer periphery of the rotor,
The chamfers in other passage grooves, especially in passage grooves having a large displacement from the standard groove formation position, are formed to be extremely displaced, and the chamfers in the groove side edges on both the left and right sides of the passage groove are formed. Has become non-uniform, and in some cases, there has been a problem that the chamfer is processed only on one side of the groove in the passage groove.

If the chamfering is not performed in a required state as described above, the passage groove in the outer peripheral portion of the rotor is rotationally displaced relatively to the passage groove on the sleeve side to switch the passage. In addition, variations in the position of the chamfer may cause a difference between the right and left hydraulic characteristics, which is a problem in terms of the flow path switching performance as a rotary valve.

It is also considered that the chamfering is performed as it is without removing the positioning jig used in the above-mentioned groove processing. It is inevitable that the hydraulic characteristics will differ from side to side due to variations in the shape of the chamfer, and in addition to this, repetitive errors of desorption for forming chamfers in each passage groove will also be piled up. It is also desired to solve the problem.

The present invention has been made in view of the above-mentioned circumstances, and in the above-described rotary valve, the unbalance of the chamfer caused by the variation in the formation position of the passage groove due to the pre-processing on the outer peripheral portion of the rotor. It is an object of the present invention to provide a method of forming a chamfer that solves the problems and minimizes the influence of variations in the formation position of the passage groove, thereby enabling a highly accurate rotary valve to be obtained.

[0015]

SUMMARY OF THE INVENTION In order to meet such a demand, a method for processing a valve chamfer of a rotary valve according to the present invention is directed to a method for forming a plurality of passage grooves formed on a rotor outer peripheral portion along a circumferential direction. In processing the chamfer, the positions of at least four or more positions among the side edges in the plurality of passage grooves for processing the chamfer are detected, and the arithmetic processing is performed based on these detected values, so that the positions of the plurality of grooves are equally distributed. The deviation amount is averaged to set a virtual center position in the groove width direction, and the chamfer is processed based on this center position.

[0016]

According to the present invention, it is possible to perform chamfering by averaging variations in the formation positions of a plurality of passage grooves in the outer peripheral portion of the rotor, and thereby obtain required fluid pressure characteristics as a rotary valve.

[0017]

1 to 5 show one embodiment of a method for processing a valve chamfer of a rotary valve according to the present invention. In these figures, in this embodiment, the power steering shown in FIGS. 4 and 5 is shown. A case in which the present invention is applied to a rotary valve 20 used as a rotary flow path switching valve in a power steering body of a steering device will be described.

First, the schematic structure of a power steering body of a power steering apparatus to which the rotary valve 20 of the present invention is applied will be briefly described with reference to FIG. 4. Reference numeral 11 denotes an input connected to a steering handle (not shown). A stub shaft 12 is connected to an inner end (left end) of the stub shaft 11 via a torsion bar 13 and meshes with a rack tooth 14a on a rack 14 constituting a steering link mechanism (not shown). 12a is a pinion shaft which is an output shaft having 12a. Note that the two shafts 11 and 12 are configured to have relative rotational displacement within a predetermined angle range due to the torsion of the torsion bar 13.

The two shafts 11 and 1 described above in a body (housing) 16 constituting a power steering main body.
A rotor 21 and a sleeve 22 constituting a rotary valve 20 serving as a rotary flow path switching valve are integrally provided on the inner end side of the pump 2 and an oil pump P and an oil tank (not shown) by relative rotational displacement. The flow path is switched between T and the left and right chambers CL and CR in the power cylinder PS as shown in FIG. The rotor 21 is formed integrally with the stub shaft 11 side,
Are integrally connected to the pinion shaft 12 side by a pin connection, and are combined by a torsion bar 13 so as to be relatively rotatable and displaced, and are provided inside a valve housing portion of the body 16.

Here, the configuration of the hydraulic circuit in the rotor 21 and the sleeve 22 and the valve housing (body 16) constituting the rotary valve 20 is well known, and the outer peripheral surface (sliding contact) of the rotor 21 which is in sliding contact with each other. As shown in FIGS. 4 and 5, a plurality of passage grooves 21a, 21b; 22a, 22b are respectively provided at predetermined intervals in the circumferential direction on the inner peripheral surface (sliding contact surface) of the sleeve 22. In addition, a plurality of passage holes (fluid supply hole 23 and fluid discharge hole 24) are formed by drilling at appropriate locations, and these passage grooves 21a, 21b;
The switching of the hydraulic circuit is controlled as necessary by the selective communication and disconnection such as b.

In FIG. 4, reference numerals 25 and 26 denote oil pumps P.
Return ports for returning the pressurized oil to the inlet port through which the pressurized oil flows from the oil tank T and the oil tank T, and left and right output ports 27A and 27B connected to the left and right cylinder chambers CL and CR of the power cylinder PS. is there.

Further, on the outer peripheral portion of the sleeve 22, FIG.
As apparent from FIG. 5 and FIG. 5, the supply-side annular groove 30, the reflux-side annular groove 31, and the left and right output-side annular grooves 32, 33 communicating with the respective ports are appropriately formed at positions shifted in the axial direction. Each of the annular grooves 30, 31; 32, 33 is connected to a port hole 25a constituting the entrance port 25, a port hole 26a constituting the return port 26, and a port hole on each output side.

The pressure oil from the pump P flows from the inlet port 25 through the supply-side annular groove 30 and the fluid supply hole 23 of the sleeve 22 into the inlet port-side passage groove 21a on the rotor 21 side. The pressure oil from the passage groove 21 a to the return port side passage groove 21 b of the rotor 21 communicating in the circumferential direction via the passage grooves 22 a and 22 b on the sleeve 22 side flows from the fluid discharge hole 24 formed in the rotor 21. , And into the rotor 21 space.

Further, the pressure oil guided to the internal space of the rotor 21 is supplied to the fluid discharge hole 34, the rotor 21 and the sleeve 22 which are formed at positions displaced in the axial direction of the rotor 21.
It is led to the return-side annular groove 31 through the annular space 35 between and the fluid discharge hole 36 formed in the sleeve 22,
It is returned from the return port 26 to the tank T side.

When the relative position between the rotor 21 and the sleeve 22 is rotationally displaced to one of the above positions, the above-mentioned return path is shut off, and the left and right output side passage grooves pass through the passage holes 37.
(Only one is shown) from the output side annular groove 32, 3
3. Pressure oil is supplied to one of the left and right chambers of the power cylinder via the output ports 27A and 27B, and the other passage system is connected to the return passage.

In the rotary valve 20 used as the rotary flow path switching valve of the power steering apparatus as described above,
In processing the chamfer 40 (see FIG. 1) on the side edges of the plurality of passage grooves 21a and 21b formed along the circumferential direction on the outer peripheral portion of the rotor 21 that switches the flow path by rotational displacement with the sleeve 22. This is performed as shown in FIGS. That is, before or during the chamfering, the outer diameter of the rotor 21 at the chamfered portion or at a portion close to the chamfered portion is determined by, for example, as shown in FIG.
By measuring the measurement results by the measuring means indicated by reference numerals 1 and 41 and feeding back the measurement results to the chamfering tool (grinding tool 53), the cutting amount of each chamfer 40 can be determined by the outer diameter of the rotor 21 in each processing portion. Performed as a processing reference

Here, such control can be easily realized by using the dimensional correction function of the NC device, and its practical advantage is great.

For example, FIG. 3 shows a schematic configuration for performing chamfering using the NC device 50.
Reference numeral 1 denotes a spindle for rotatably holding a rotor 21 (stub shaft 11) as a work; 52, a chuck for clamping the rotor 21 at a predetermined rotational position; 53, an advancing / retreating operation with respect to the clamped rotor 21 in a centripetal direction. Passage groove 21
A grinding tool 56 for performing chamfering on both side edges of a and 21b, and a CPU 56 for controlling a cutting amount by the grinding tool 53 by feeding back a measurement result from the measuring means 41, 41. In addition, 54 is an electric motor for rotating the grinding tool 53, and 55 is the grinding tool 5
Reference numeral 3 denotes a mechanism for performing the forward / backward operation.

That is, the outer diameter of a portion of the outer peripheral portion of the rotor 21 close to the chamfered portion is measured by the measuring means 4.
1, 41, a predetermined cutting amount is given to the processing tool (53) based on the outer diameter of the rotor 21, and a plurality of chamfers 4 formed on the outer peripheral portion of the rotor 21 as a whole are provided.
The variation in shape between 0, 40, and ‥‥ is reduced.

According to this processing method, the rotor 2
As shown in FIGS. 1A and 1B, even if the outer diameter at the outer peripheral portion is partially changed due to pre-processing or heat treatment of the rotor 21, the outer diameter of the rotor 21 is not changed. Without being affected by the absolute size of the outer diameter at the outer peripheral portion, the chamfer 40,
40 can be formed at a predetermined position with an appropriate cut amount,
As a result, it is possible to obtain the opening amount, the overlap angle, and the underlap angle of the valve 20 at a desired rotation angle, thereby reducing the variation in the flow control characteristics and reducing the internal leakage of the rotary valve 20 at low cost. Can be manufactured.

For example, in FIGS. 1 (a) and 1 (b), a solid line indicates a normal outer diameter shape of the rotor 21. In this case, the passage grooves 21a and 21b and their chamfer forming portions are indicated by two-dot chain lines in the figure. When the outer diameter is deformed in the bulging direction as shown in the figure, if chamfering is performed on the basis of the center of the rotor 21 in the same manner as in the prior art, the According to this processing method, the outer diameter of the chamfer forming portion 21A at the outer periphery of the rotor is measured by the measuring means 41, 41.
By performing chamfer processing based on this,
As shown by 40a in the figure, an appropriate cut amount and chamfer shape can be obtained. And according to this processing method,
Compared with the conventional method, the variation of the chamfers 40, 40 by the angle Δθ can be eliminated, and thereby the chamfers 40, 40
Thus, a required flow path switching function can be obtained.

Therefore, in the conventional method, FIG.
The case where the outer diameter of the rotor 21 is deformed so as to increase as shown in FIG. 2 and the case where the outer diameter of the rotor 21 is deformed so as to decrease as shown in FIG.
Although the overlap angle at the time of steering is apparently different from θ1 and θ2, this processing method can solve such a problem. This is the rotor 21
This is because the shapes of the chamfers 40 and 40a are formed to be substantially the same according to the outer diameter of the chamfers.

Next, the valve chamfering method according to the present invention will be described in detail with reference to FIGS. FIG. 6 is a schematic configuration diagram of a processing machine used to carry out the valve chamfering method according to the present invention, and FIG. 7 is a schematic cross-sectional view of the rotor. FIG. (B) shows the rotor in which the position of the passage groove is shifted, and (c) and (d) show the rotor in which the chamfer is formed by the processing method according to the present invention. FIG. 8 is a schematic sectional view of a rotor on which a chamfer is formed by a conventional processing method.

The passage grooves 21a and 21b are
7A along the circumferential direction, generally, it is formed at a position equally distributed on the outer peripheral portion of the rotor 21 as shown in FIG. However, even if it is manufactured with high precision, actually, as shown in FIG.
As shown by A, B, C, and D, respectively, the passage grooves 21a and 21b are often formed so as to be shifted from the equidistant positions.

In such a case, the chamfers 40, 40 having the required cut amount and chamfer shape cannot be formed when the chamfering is performed on each of the passage grooves 21a, 21b, as described above. For this reason, this embodiment attempts to solve such a problem.

That is, in the rotor 21 in the state of FIG.
When the chamfer processing is performed so that b is equal to the left and right with reference to the deviation B, the state shown in FIG. 8A is obtained. When the groove 21a is machined, as shown in FIG.
The left and right become uneven. This figure shows a case where no chamfer is formed on one side.

In order to solve such a problem, according to the present invention, the chamfers 40, 40 are formed on both side edges of the plurality of passage grooves 21a, 21b formed along the circumferential direction on the outer peripheral portion of the rotor 21. At the time of processing, at least four or more positions of both side edges of the plurality of passage grooves 21a and 21b for processing the chamfer 40 are detected by a measuring tool 60 as shown in FIG. 6, and the groove position information is obtained. The position of the virtual passage groove is set based on the detected value shown, and the chamfer 40 is machined in this passage groove.

More specifically, the positions of both side edges of at least four or more passage grooves 21a and 21b are detected by the measuring tool 60, and arithmetic processing is performed based on these detected values, whereby a plurality of passage grooves 21a and 21b are detected. The deviation from the equidistant position of 21b is averaged to set a virtual center position in the groove width direction. Then, based on this center position, the chamfer 40
Set the processing start point of

Here, referring to FIG.
The groove position information 61 based on “0” is sent to the CPU 56, where the virtual center position in the groove width direction is calculated and obtained by selectively considering the groove width information 62. The above-described groove width information 62 may be omitted.

Then, based on the calculation result obtained by the CPU 56, the rotary encoder 63 and the motor 64 are driven to drive the rotation angle position of the rotor 21, which is a work, to a predetermined position by the drive mechanisms 65 and 66. Passage groove 2
It is preferable to stop the rotation at the positions 1a and 21b and to perform chamfering with a cutting tool (not shown).

FIGS. 7 (c) and 7 (d) show a case where the chamfering is performed by using the present invention. The two side grooves of the passage grooves 21b and 21a are formed with other passage grooves, respectively. It is possible to perform chamfer processing in consideration of the relationship.

If the positions of the side edges of the passage grooves 21a and 21b are detected on a chamfering grinder, it is possible to eliminate the accumulation of errors due to attachment and detachment and to minimize the processing errors. It is.

Therefore, according to this chamfering method, a plurality of side edge positions of a plurality of passage grooves 21a and 21b formed along the circumferential direction in the outer peripheral portion of the rotor 21 are detected at a plurality of positions, and based on these detected values. A plurality of passage grooves 2
Since the imaginary center position in the groove width direction is set by averaging the amounts of deviation from the equidistant positions of 1a and 21b and the chamfer 40 is processed based on this center position, a plurality of passages in the outer peripheral portion of the rotor 21 are formed. The chamfer processing can be performed by averaging the variation in the formation positions of the grooves 21a and 21b, thereby eliminating the chamfer 40 that is extremely deviated from the groove side edge, and it is possible to obtain the required fluid pressure characteristics as the rotary valve 20.

That is, if the above-described processing method is adopted, the variation in the circumferential formation position between the passage grooves 21a and 21b in the outer peripheral portion of the rotor 21 due to the processing error of the groove formation position on the grinding machine is reduced. However, it is possible to obtain the rotary valve 20 having a small difference between left and right in terms of fluid pressure characteristics (oil pressure characteristics).

In the above-described processing method, the underlap angle between the rotor 21 and the sleeve 22 in the rotary valve 20 can be stabilized.
Can be obtained smoothly, and the pressure loss can be reduced.

In particular, when the chamfering is performed on the basis of the groove having the reverse deviation, the opening area becomes large, and the right and left difference tends to be promoted in the fluid pressure circuit. Therefore, a valve having stable characteristics can be obtained.

It should be noted that the present invention is not limited to the structure of the embodiment described above, and the shape, structure, etc. of each part of the rotary valve 20 can be freely modified and changed as appropriate, and various modifications are conceivable. Further, in the above-described embodiment, the case where the present invention is applied to the rotary valve 20 used as the rotary flow path switching valve in the power steering apparatus has been described. However, the present invention is not limited to this, and may be applied to various fields. The present invention can be applied to a rotary valve used for fluid control and exert its effects.

[0048]

As described above, according to the valve chamfer machining method for a rotary valve according to the present invention, the chamfer is machined on both side edges of a plurality of passage grooves formed along the circumferential direction on the outer periphery of the rotor. By detecting at least four or more positions among the side edges in the plurality of passage grooves for processing the chamfer, and calculating the average based on the detected values, the deviation amount from the equidistant positions of the plurality of grooves is averaged. The center position in the virtual groove width direction was set, and the chamfer was processed based on this center position. When the chamfering is performed on both side edges of the respective passage grooves, the positions of the plurality of passage grooves formed on the outer peripheral portion of the rotor may vary. This makes it possible to achieve the required fluid pressure characteristics as a rotary valve by preventing the imbalance due to the chamfer position and machining state as in the past, eliminating the left-right difference in the fluid pressure circuit. Has an effect.

[Brief description of the drawings]

FIGS. 1A and 1B show an example of a method of processing a valve chamfer of a rotary valve, wherein FIG. 1A is a schematic sectional view of a rotor, and FIG.

FIG. 2 is an enlarged sectional view showing a part of a rotary valve formed by a conventional valve chamfering method.

FIGS. 3A and 3B are schematic explanatory views illustrating processing machines for processing a valve chamfer of a rotary valve.

FIG. 4 is a schematic cross-sectional view showing a power steering main body in a power steering apparatus suitable for applying the rotary valve according to the present invention.

FIG. 5 is a schematic configuration diagram for explaining a schematic configuration of a rotary valve and a power cylinder serving as a rotary flow path switching valve in FIG. 4;

FIG. 6 is a schematic configuration diagram of a processing machine used for performing the valve chamfering method according to the present invention.

FIG. 7 is a schematic sectional view of a rotor.

FIG. 8 is a schematic sectional view of a rotor on which a chamfer is formed by a conventional processing method.

[Explanation of symbols]

Reference numeral 20: rotary valve, 21: rotor, 21a: rotor passage groove, 21b: rotor passage groove, 22: sleeve,
40: chamfer, 52: chuck, 53: grinding tool (working tool), 56: CPU, 60: measuring tool, P: oil pump, T: oil tank, PS: power cylinder.

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Claims (1)

(57) [Claims] 1. A plurality of passage grooves communicating with an entrance port, a return port or an output port are formed in a circumferential direction on a sliding contact surface of a rotor and a sleeve that are relatively rotatably combined, and these are selected. In the rotary valve, which performs flow path switching by selectively communicating and blocking, when machining chamfers on both side edges of each of the passage grooves on the outer peripheral portion of the rotor, of the plurality of passage grooves for machining the chamfer, At least four or more positions are detected, and arithmetic processing is performed based on these detected values, thereby averaging the deviation amounts from the equidistant positions of the plurality of grooves and imagining them.
Set the center position in the groove width direction of
A method for processing a chamfer of a rotary valve, comprising: