JPH0513882U - Hydraulic control valve - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] When abnormal steering operation force is applied to the steering wheel when exiting from a falling wheel, etc., prevent damage to each part of the steering wheel and reduce power assist steering force. Relieves shock caused by sudden reduction or disappearance. A valve sleeve 12 having a plurality of hydraulic oil inlet passages 24 and a plurality of hydraulic oil supply passages 26a and 26b, and a valve body 14 inserted into the valve sleeve 12 and having a plurality of hydraulic oil passages. In the rotary hydraulic control valve 10,
First and second land portions 22 formed on the outer peripheral surface of the valve body 14.
A recessed portion 40 extending in the axial direction in each of a and 22b
a, 40b to form a valve body 14 for the valve sleeve 12
When the relative rotational displacement amount of the hydraulic fluid exceeds a preset displacement amount, the hydraulic oil supply passages 26a and 26b
38.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a hydraulic control valve that is suitable for use in a power steering device of an automobile.

[0002]

[Prior Art]

 2. Description of the Related Art In large vehicles such as trucks, a hydraulic power steering device is widely used to assist the steering force of a driver. This type of power steering device is generally composed of a hydraulic cylinder that assists the steering force and a hydraulic control valve that switches the hydraulic oil supplied to the hydraulic oil chambers on both sides of the piston of the hydraulic cylinder according to the steering direction. The hydraulic control valve is a rotary hydraulic control that consists of a valve sleeve that causes relative rotational displacement in conjunction with the steering operation of the driver and a valve element that is coaxially inserted into the valve sleeve. The valve is often used. Now, a typical configuration of a conventional rotary hydraulic control valve will be described with reference to FIGS. A hydraulic control valve, generally designated by reference numeral 10, is a hollow cylindrical valve sleeve 12 and is inserted into the valve sleeve 12 coaxially and freely relative to each other about an axis. It is composed of a valve body 14. Although not shown, the valve element 14 operates on the steering shaft so that a relative steering displacement around the axis is generated with respect to the valve sleeve 12 by the driver steering the steering wheel. Are linked together.

On the inner peripheral cylindrical surface of the valve sleeve 12, a plurality of first and second groove portions 16 a and 16 b (four in the illustrated embodiment, respectively) and a plurality of first and second lands extending in the axial direction, respectively. Portions 18a and 18b (four in the illustrated embodiment) are formed alternately in the circumferential direction. As shown in the drawing, four first land portions 18a are arranged at substantially equal intervals in the circumferential direction, and the first land portions 18a are adjacent to one side in the circumferential direction of each land portion 18a, that is, the clockwise side. The first groove portion 16a is arranged, and the second groove portion 16b is arranged adjacent to the other side, that is, the counterclockwise side. On the other hand, on the outer peripheral surface of the valve body 14, a plurality of first and second groove portions 20a and 20b (each four in the illustrated embodiment) and a plurality of first and second land portions 22a extending in the axial direction, respectively. And 22b (four in the illustrated embodiment) are formed alternately in the circumferential direction. The four first groove portions 20a are arranged at substantially equal intervals in the circumferential direction and correspond to the first land portions 18a of the valve sleeve 12, and the second groove portions 20b are the second groove portions of the valve sleeve 12. It is arranged corresponding to the land portion 18b. A first land portion 22a corresponding to the first groove portion 16a of the valve sleeve 12 is disposed adjacent to one circumferential direction side of each first groove portion 20a, that is, a clockwise direction side, and the other side, that is, a counterclockwise direction. A second land portion 22b corresponding to the second groove portion 16b of the valve sleeve 12 is disposed adjacent to the side.

Although not shown, three independent annular grooves are formed on the inner peripheral surface of the housing of the power steering device supporting the valve sleeve 12 at intervals in the axial direction of the valve sleeve. .. The valve sleeve 12 is provided with four radial hydraulic oil inlet passages 24 penetrating from the inner peripheral surface of each first land portion 18a to the outer peripheral surface of the sleeve, and from the bottom surface of the first groove portion 16a to the outer peripheral surface of the sleeve. There are four radial first working oil supply passages 26a penetrating therethrough, and further four second radial hydraulic oil supply passages 26b penetrating from the bottom surface of the second groove portion 16b to the sleeve outer peripheral surface. Has been drilled. The hydraulic oil inlet passage 24, the first hydraulic oil supply passage 26a, and the second hydraulic oil supply passage 26b are arranged at intervals in the axial direction. Further, the four hydraulic oil inlet passages 24 are provided with a pressure oil source through one of three annular grooves formed on the inner peripheral surface of the housing of the power steering device, that is, a first annular groove. It is connected to the discharge side of the power steering oil pump 28. On the other hand, the four first hydraulic oil supply passages 26a are connected to the first hydraulic oil chamber 32a of the steering force assisting pressure oil response device 30 via the second annular groove on the inner peripheral surface of the housing, and The four second hydraulic oil supply passages 26b are connected to the second hydraulic oil chamber 32b of the pressure oil responsive device 30 via a third annular groove on the inner peripheral surface of the housing. The hydraulic oil is supplied to the first working oil chamber 32a of the same pressure oil responding device 30, and the second hydraulic oil chamber 32b is connected to the oil storage source, that is, the oil pan 34. Steering force is generated, hydraulic oil is supplied to the second hydraulic oil chamber 32b, and the first hydraulic oil chamber 32b is communicated with the oil pan 34 so that a steering force in the opposite direction, for example, leftward is generated. It is provided in.

A first hydraulic oil return passage 36, which extends in the axial direction and communicates with the oil pan 34, is provided in the central portion of the valve body 14, and the first hydraulic fluid return passage 36 is formed in the radial direction. The second hydraulic oil return passages 38 communicate with the bottom surface of the second groove portion 20b. As is well known in the art, an input member of the steering device (the valve member 14 is connected to the input member) and an output member (the valve sleeve 12 is connected to the output member). A torsion bar (not shown) is connected to the first working oil return passage 36 by coaxial loose insertion.

In the above device, when the steering wheel is not operated, no torsion force is generated in the torsion bar, no torsional displacement is generated between the input shaft and the output shaft of the steering device, and the hydraulic control valve. 10 is in a neutral state. At this time, as shown in FIG. 10, the first land portion 18a of the valve sleeve 12 and the first groove portion 20a of the valve body 14, the second land portion 18b of the valve sleeve 12 and the second groove portion 20b of the valve body 14, The first groove portion 16a of the valve sleeve 12 and the first land portion 22a of the valve body 14, and the second groove portion 16b of the valve sleeve 12 and the second land portion 22b of the valve body 14 are opposed to each other. A sufficient gap is formed between the first land portion 18a and the first land portion 22a and the second land portion 22b of the valve body 14 on both sides of the first land portion 18a. Therefore, the hydraulic oil supplied from the oil pump 28 to the hydraulic oil inlet passage 24 of the valve sleeve 12 enters the first groove portion 20a of the valve body 14 as shown by the arrow in FIG. The oil flows to the first groove portion 16a and the second groove portion 16b of the valve sleeve 12, further passes through the second groove portions 20b of the valve body 14 on both sides thereof, and passes through the second hydraulic oil return passage 38, and then from the first hydraulic oil return passage 36. It flows into the pan 34. The first and second hydraulic oil supply passages 26a and 26b, which are in communication with the first and second hydraulic oil chambers 32a and 32b of the pressure oil responding device 30, respectively, are connected via the first and second groove portions 16a and 16b. Since this also communicates with the oil pan 34 and is open to the atmosphere, the pressure oil response device 30 does not operate.

Next, when the driver drives the steering wheel from the neutral position to the right, as shown in FIG. 11, it is loosely inserted into the first hydraulic oil return passage 36 of the valve body 14. The valve element 14 slightly moves clockwise with respect to the valve sleeve 12 via the torsion bar. Therefore, the first land portion 22a of the valve body 14 slides on the second land portion 18b of the valve sleeve 12 so that the first hydraulic oil supply passage 26a in the valve sleeve and the second hydraulic fluid return passage 38 in the valve body are connected. The communication is cut off, and the second hydraulic oil supply passage 26b and the second hydraulic oil return passage 38 are still kept in communication. Therefore, the hydraulic fluid supplied from the oil pump 28 to the hydraulic fluid inlet passage 24 passes through the first hydraulic fluid supply passage 26a through the first groove portions 20a and 16a, and the first hydraulic fluid chamber 32a of the hydraulic fluid responding device 30. Is supplied to the second hydraulic oil return passage 38 from the second hydraulic oil supply passage 26b through the second groove portions 16b and 20b. Then, the oil is discharged to the oil pan 34 via the first hydraulic oil return passage 36. As a result, the piston of the pressure oil responsive device 30 is displaced to the left in FIG. 10, and the output member of the steering device is displaced in the direction in which a rightward steering force is generated to provide power assistance.

Conversely, when the driver drives the steering wheel from the neutral position to the left, as shown in FIG. 12, it is loosely inserted into the first hydraulic oil return passage 36 of the valve body 14. The valve element 14 slightly moves counterclockwise with respect to the valve sleeve 12 via the torsion bar. For this reason, the second land portion 22b of the valve body 12 is brought into sliding contact with the second land portion 18b of the valve sleeve 12 so that the second hydraulic fluid supply passage 26b in the valve sleeve and the second hydraulic fluid return passage 38 in the valve body. While the communication is cut off, the first hydraulic oil supply passage 26a and the second hydraulic oil return passage 38 are still maintained in the communication state. Therefore, the operating pressure oil supplied from the oil pump 28 to the operating oil inlet passage 24 passes through the first groove portion 20a and the second groove portion 16b, and passes through the second operating oil supply passage 26b to the second portion of the pressure oil responding device 30. While being supplied to the hydraulic oil chamber 32b, the hydraulic oil in the first hydraulic oil chamber 32a of the same pressure oil responsive device passes from the first hydraulic oil supply passage 26a to the first groove portion 16a and the second groove portion 20b. It flows into the second hydraulic oil return passage 38, and then is discharged to the oil pan 34 via the first hydraulic oil return passage 36. As a result, the piston of the pressure oil responsive device 30 is displaced to the right in FIG. 10, and the output member of the steering device is displaced in the direction in which the leftward steering force is generated to provide power assistance.

In the power steering device including the hydraulic control valve as described above, when the steering wheel is operated to the right or left to the limit, the first or second hydraulic oil chamber of the pressure oil response device 30 is operated. Since the operating pressure oil remains applied to 32a or 32b, there is a concern that the steering linkage may be damaged especially in a vehicle such as a medium- or large-sized truck having a large power-assisted steering force. Also, even when the steering wheel is not operated to the right or left to the limit, steering may occur if the wheel falls into a groove and tries to escape, or if a strong driving force is applied to the steering wheel on a very bad road. There is a risk that an extremely large steering force, which is a combination of the power assisted steering force and the artificial steering force based on the hydraulic pressure of the pressure oil responsive device 30, acts on the linkage of the ring device, resulting in damage to the linkage.

[0010]

[Problems to be solved by the device]

 The present invention was devised in view of the above circumstances, and when the driver operates the steering wheel in either the left or right direction to the limit and further applies a driving operation force, the steering wheel is used to escape when the wheel falls. Power-assisted steering generated by the pressure oil response device of the steering device when a strong driving force is applied to the wheel, or when a strong driving force is applied to the steering wheel when driving on a rough road. The force is removed to prevent damage to the steering linkage, and the shock caused by the removal of the power-assisted steering force is mitigated to effectively provide anxiety and discomfort to the driver operating the steering wheel. The purpose is to reduce

[0011]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention has a plurality of axially extending grooves and lands that are alternately formed on the inner peripheral surface in the circumferential direction, and one end of which communicates with a pressure oil source. A plurality of hydraulic oil inlet passages, the other end of which is open to the land or groove, and circumferentially opposite sides of each hydraulic oil inlet passage, one end of which is open to the groove and the other end of which is the operation of the pressure oil response device. A valve sleeve having a plurality of hydraulic oil supply passages that communicate with the oil chamber, and a valve sleeve that is inserted into the valve sleeve so as to be rotatable around the above-mentioned axis, and that has a plurality of axial lines in its outer circumferential surface. A valve body having a plurality of hydraulic oil return passages in which extending groove portions and land portions are alternately formed in the circumferential direction, and one end opens to the groove portion or land portion and the other end communicates with an oil storage source In the neutral state, the valve sleeve, the groove portion of the valve body, and the land portion are in phase with each other. The hydraulic oil supplied from the hydraulic oil inlet passage in the opposite direction flows into the hydraulic oil return passage, and when the valve element rotates relative to the valve sleeve from the neutral state, the valve sleeve and the land portion of the valve element slide against each other. And the communication between the hydraulic oil inlet passage and the hydraulic oil return passage is cut off, and the hydraulic oil supplied from the hydraulic oil inlet passage is supplied from one of the hydraulic oil supply passages on both sides of the hydraulic oil inlet passage to the pressure oil response device. In the one configured to be supplied to one of the hydraulic oil chambers, the relative rotational displacement amount of the valve element with respect to the valve sleeve from the neutral state is preset in the land portion of the valve sleeve or the valve element. When it exceeds the variable position, a recess is formed in order to allow the one hydraulic oil supply passage communicating with the hydraulic oil inlet passage and the hydraulic oil chamber of the pressure oil response device to flow to the hydraulic oil return passage. Is characterized by It proposes a hydraulic control valve.

[0012]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. (Note that members and parts that are substantially the same as or correspond to those of the conventional device described with reference to FIGS. 10 and 12 are denoted by the same reference numerals, and redundant description will be omitted.)

First, in the first embodiment of the present invention shown in FIGS. 1 to 5, four inner circumferential cylindrical surfaces of the valve sleeve 12 are arranged at approximately four equal positions in the circumferential direction. Groove-shaped recesses 40a and 40b extending in the axial direction are formed in the first and second land portions 22a and 22b formed on the outer peripheral surface of the valve body 14 arranged on both sides in the circumferential direction of the one land portion 18a, respectively. It is provided. As well shown in the enlarged cross-sectional view of FIG. 4, the groove width W in the circumferential direction of the recesses 40a and 40b is equal to the first land of the upper portion indicated by reference numeral I in FIGS. The first and second land portions 22a and 22b located on both sides of the portion 18a, the same first and second land portions 22a and 22b on the right side portion indicated by the reference numeral II, and the same on the lower portion indicated by the reference numeral III. The first and second land portions 22a and 22b and the similar first and second land portions 22a and 22b of the left side portion indicated by the reference numeral IV are formed by slightly displacing each portion. Alternatively, as shown in the enlarged cross-sectional view of FIG. 5, the circumferential groove width w'of the recesses 40a and 40b provided in the first and second lands 22a and 22b may be the same as I or The effective width W of the recesses 40a and 40b may be slightly changed in each of the portions I to IV by forming the same in all the IV portions and slightly changing the size of the chamfer C on the top surface.

FIG. 1 shows a neutral state of the hydraulic control valve 10. The flow of hydraulic oil at this time is substantially the same as that of the conventional hydraulic control valve shown in FIG. Aid Does not generate steering force. FIG. 2 shows a state in which the driver operates the steering wheel to the right with normal operating force, and the flow of hydraulic oil at this time is substantially the same as that of the conventional hydraulic control valve shown in FIG. Therefore, the power assisting force for rightward steering is generated by the pressure oil responsive device 30. FIG. 3 shows a case where the steering wheel is driven to the right with a larger operating force than usual in order to escape, for example, when the wheel falls in the groove. When the driver strongly pushes the steering wheel with a large force that exceeds the normal steering force against the large steering resistance in an attempt to get out of the fallen wheel state, the valve element 14 is further pushed through the torsion bar than in the case of FIG. It is greatly moved clockwise. Therefore, the recess 40b provided in the second land portion 22b of the valve body 14 communicates with the hydraulic oil inlet passage 24, and the hydraulic oil inlet passage 24 and the second groove portions 16b and 20b communicate with each other via the concave portion 40b. It Therefore, the hydraulic oil supplied to the hydraulic oil inlet passage 24 flows into the second hydraulic oil return passage 38 opening to the second groove portion 20b, and at the same time, the second hydraulic oil response device 30 passes through the second hydraulic oil supply passage 26b. The hydraulic oil chamber 32b communicates with the return passage 38. On the other hand, the working oil supply passage 26a also communicates with the second working oil return passage 38 through the path of the first groove 16a → the first groove 20a → the working oil inlet passage 24 → the recess 40b, and further the first working oil return passage 36. Through the oil pan 34, the power assist steering force generated by the pressure oil responsive device 30 is reduced and disappears over time. On the contrary, when the steering wheel is moved to the left by a large steering operation force, the recess 40 provided in the first land portion 22a of the valve body 14 operates in the same manner as described above, and the pressure oil response device 30 operates. The power-assisted steering force that had been generated diminishes and disappears over time. Therefore, an excessive force does not act on each part of the steering device, particularly the linkage, and the damage of the linkage and the like can be effectively prevented.

In the above case, if the circumferential widths W of the recesses 40a and 40b provided in the first and second land portions 22a and 22b of the above I to IV portions are all the same, In the diagram of FIG. 6 in which the axis represents the hydraulic oil pressure P in the first or second hydraulic oil chamber 32a or 32b of the pressure oil response device 30 and the horizontal axis represents time T, the solid line A indicates As described above, when a large operating force is applied to the steering wheel by the driver, the four recesses 40a or 40b simultaneously communicate with the hydraulic oil inlet road 24, so that the hydraulic oil pressure of the hydraulic oil responding device 30 suddenly increases. Since the steering torque suddenly changes, the shock sensed by the driver through the steering wheel is large, and there is a problem that the driver feels uncomfortable and uncomfortable. However, according to the present invention, since the circumferential widths W of the recesses 40a and 40b of the I to IV portions are slightly different, a large steering operation force is applied to the steering wheel. When the relative rotation angle of the valve body with respect to the valve sleeve 12 increases, the recesses 40a and 40b having a large width W in the circumferential direction sequentially communicate with the hydraulic oil inlet passage 24, so that the dotted line B is shown in FIG. As described above, the hydraulic oil pressure of the pressure oil response device 30 is gradually decreased, and the shock due to the change in the steering torque is alleviated. Therefore, the anxiety and discomfort given to the driver can be effectively removed. You can

Next, a second embodiment of the present invention will be described with reference to FIGS. In this hydraulic control valve 10, four first groove portions 42a and four second groove portions 42b are alternately arranged in a circumferential direction on the inner peripheral cylindrical surface of the valve sleeve 12, and four groove portions are arranged between these groove portions. First land portions 44a and four second land portions 44b are alternately formed in the circumferential direction. On the other hand, on the outer peripheral surface of the valve body 14, four first groove portions 46a corresponding to the first land portions 44a of the valve sleeve 12 and four second groove portions 46b corresponding to the second land portions 44b of the valve sleeve 12 are provided. Are alternately formed in the circumferential direction, and between these groove portions, four first land portions 48a corresponding to the first groove portions 42a of the valve sleeve 12 and four corresponding to the second groove portions 42b of the valve sleeve 12 are formed. The individual second land portions 48b are alternately formed in the circumferential direction. A hydraulic oil supply passage 24 communicating with a pressure oil source, that is, a power steering oil pump 28 is radially bored in the first groove portion 42a of the valve sleeve 12, and the first and second land portions 44a on both sides thereof are formed. And 44b, first and second hydraulic oil supply passages 26a and 26b communicating with the first and second hydraulic oil chambers 32a and 32b of the pressure oil responsive device 30, respectively, are formed in the radial direction, and Recesses 50a and 50b similar to the recesses 40a and 40b of the first embodiment are provided in the land portions 44a and 44b. On the other hand, a second hydraulic oil return passage 38 extending in the radial direction is bored in the second land portion 48b of the valve body 14, and a first portion extending in the axial direction is formed in the central portion of the valve body 14. A hydraulic oil return passage 36 is provided. The first hydraulic oil return passage 36 is communicated with the oil pan 34, and a torsion bar is loosely inserted therein as in the conventional hydraulic control valve. The width W in the circumferential direction of the recesses 50a and 50b is formed to change slightly in the portions I to IV as in the first embodiment.

FIG. 7 shows a neutral state of the hydraulic control valve 10. The hydraulic oil supplied from the pressure oil source to the hydraulic oil inlet passage 24 is divided into both sides in the circumferential direction, as shown by the arrow in the figure, and the first groove portion 42a of the valve sleeve 12 → the valve body 14 The first and second groove portions 46 a and 46 b → the second groove portion 42 b of the valve sleeve 12 → the second hydraulic oil return passage 38 of the valve body 14 → the first hydraulic oil return passage 36 flow to the oil pan 34. Therefore, both the first and second hydraulic oil chambers 32a and 32b of the pressure oil response device 30 are in communication with the atmosphere, and the pressure oil response device is in a neutral state. FIG. 8 shows a case where a normal rightward operating force is applied to the steering wheel. The first land portion 48a and the second land portion 48b of the valve body 14 and the first land portion 44a and the second land portion 44b of the valve sleeve 12 are in sliding contact with each other, and the hydraulic oil inlet passage 24 and the second hydraulic oil are provided. The supply passage 26b communicates with the first groove portion 42a and the second groove portion 46b. On the other hand, the first hydraulic oil supply passage 26a communicates with the second hydraulic oil return passage 38 in the valve body 14 via the first groove portion 46a and the second groove portion 42b, and further passes through the first hydraulic oil return passage 36 to the oil pan. 34. As a result, the working oil is supplied from the second working oil supply passage 26b to the second working oil chamber 32b of the pressure oil responding device 30, and the working oil in the first working oil chamber 32a is transferred to the first working oil. The oil is discharged into the oil pan 34 through the supply passage 26a, and the pressure oil responsive device 30 provides power assistance for the right steering. Similarly, when a normal leftward operating force is applied to the steering wheel, the working oil inlet passage 24 and the first working oil supply passage 26a communicate with each other so that working pressure oil is fed to the first pressure oil response device 30. While being supplied to the hydraulic oil chamber 32a, the hydraulic oil in the second hydraulic oil chamber 32b of the same-pressure oil response device 30 is supplied from the second hydraulic oil supply passage 26b to the second hydraulic oil return passage 38 and the first hydraulic oil return passage. The oil is discharged into the oil pan 34 via 36. As a result, power assistance for the left steering is provided by the pressure oil responsive device 30.

Next, FIG. 9 shows a state in which the steering wheel is further rotated to the right with a strong operating force from the state of FIG. 8 in order to escape, for example, when the wheel falls into a groove. At this time, as shown in the left half of the drawing, the second hydraulic oil return passage 38 of the second land portion 48b of the valve body 14 communicates with the recess 50b provided in the second land 44b of the valve sleeve 12. Therefore, the hydraulic oil inlet passage 24 and the second hydraulic oil supply passage 26b communicate with the return passage 38, and the first hydraulic oil supply passage 26a is connected to the first hydraulic oil supply passage 26a as shown in the right half of the drawing. It communicates with the second hydraulic oil return passage 38 via the first groove portion 46a and the second groove portion 42b. Therefore, the hydraulic oil pressures of the first and second hydraulic oil chambers 30a and 30b of the pressure oil responsive device 30 are reduced, and with the lapse of time, the hydraulic oil pressure is lowered to near atmospheric pressure, and the power assistance of the pressure oil responsive device is canceled. As a result, an excessive force is prevented from acting on each part of the steering device, and damage to the linkage and the like is prevented. At this time, by slightly changing the widths of the four sets of recesses 50a and 50b in the circumferential direction for each set, the power assist steering force of the pressure oil responsive device 30 is exactly the same as in the first embodiment. Since the shock that is gradually changed without sudden change and transmitted to the driver through the steering wheel is alleviated, the anxiety and discomfort caused by the shock can be effectively eliminated or at least reduced.

In the above embodiment, the hydraulic oil supply passages 24 are arranged at four positions in the circumferential direction of the valve sleeve 12 and four sets of related grooves and lands are arranged, respectively. It is also possible to arrange the supply passages and the related grooves and lands at three positions in the circumferential direction, and further to arrange five or more positions if desired.

[0020]

[Effect of the device]

 As described above, in the hydraulic control valve according to the present invention, a plurality of axially extending grooves and lands are alternately formed on the inner peripheral surface in the circumferential direction, and one end of the hydraulic control valve is compressed. A plurality of hydraulic oil inlet passages that are in communication with the oil source and the other end of which is open to the land or groove, and are arranged on both sides in the circumferential direction of each hydraulic oil inlet passage, one end of which is open to the groove and the other end of which is pressure oil responsive. A valve sleeve having a plurality of hydraulic oil supply passages communicating with the hydraulic oil chamber of the device, and a valve sleeve inserted into the valve sleeve so as to be rotatable around the axis and having a plurality of outer peripheral surfaces. A groove portion and a land portion extending in the axial direction are alternately formed in the circumferential direction, and a plurality of hydraulic oil return passages having one end open to the groove portion or the land portion and the other end communicating with an oil storage source are provided. It is composed of a valve body, and in the neutral state, the groove and land of the valve sleeve and the valve body. Are opposed to each other and the hydraulic oil supplied from the hydraulic oil inlet passage flows into the hydraulic oil return passage, and when the valve body rotates relative to the valve sleeve from the neutral state, the valve sleeve and the land portion of the valve body Slides into contact with each other to cut off the communication between the hydraulic oil inlet passage and the hydraulic oil return passage, and the hydraulic oil supplied from the hydraulic oil inlet passage is supplied from one of the hydraulic oil supply passages on both sides of the hydraulic oil inlet passage to the pressure oil. In the one configured to be supplied to one hydraulic oil chamber of the response device, in the land portion of the valve sleeve or the valve body, the relative rotational displacement amount of the valve body with respect to the valve sleeve from the neutral state is beforehand measured. A recess that allows one of the hydraulic oil supply passages communicating with the hydraulic oil inlet passage and the hydraulic oil chamber of the pressure oil responding device to flow sequentially to the hydraulic oil return passage when different set displacements are exceeded. Is formed Therefore, it is possible to effectively prevent damage to the steering linkage, etc., which is likely to occur when an extremely large rotational operation force is applied to the steering wheel, such as when the vehicle is on a falling wheel or traveling on a rough road. It is practically useful because it can alleviate the shock caused by the disappearance or reduction of the power assisting power of the vehicle and eliminate or reduce the anxiety and discomfort given to the driver.

[Brief description of drawings]

FIG. 1 is a sectional view showing a neutral state of a hydraulic control valve according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the hydraulic control valve shown in FIG. 1 during normal steering.

FIG. 3 is a cross-sectional view showing an aspect of a hydraulic control valve when a steering operation force larger than that in FIG. 2 is applied.

FIG. 4 is an enlarged cross-sectional view showing an extracted essential part of the hydraulic control valve shown in FIG.

5 is an enlarged cross-sectional view showing a main part of the hydraulic control valve shown in FIG. 1 in an extracted manner.

6 is a diagram showing a change in hydraulic oil pressure supplied to a pressure oil responsive device by the hydraulic control valve shown in FIG.

FIG. 7 is a sectional view showing a neutral state of a hydraulic control valve according to a second embodiment of the present invention.

8 is a cross-sectional view showing the hydraulic control valve shown in FIG. 7 during normal steering.

9 is a cross-sectional view showing an aspect of a hydraulic control valve when a steering operation force larger than that in FIG. 8 is applied.

FIG. 10 is a schematic configuration diagram showing a neutral state of a conventional hydraulic control valve.

11 is a cross-sectional view showing the hydraulic control valve shown in FIG. 10 during normal steering.

12 is a cross-sectional view showing an aspect of the hydraulic control valve when a steering operation force larger than that in FIG. 11 is applied.

[Explanation of symbols]

10 ... Hydraulic control valve, 12 ... Valve sleeve, 14 ... Valve body, 2
4 ... Working oil inlet passage, 26a and 26b ... Working oil supply passage, 28 ... Pressure oil source, 30 ... Pressure oil responding device, 36 and 38
… Hydraulic oil return passage, 34… Oil storage source

Claims (1)

[Scope of utility model registration request] 1. A plurality of axially extending grooves and lands are alternately formed on the inner peripheral surface in the circumferential direction, and one end is connected to a pressure oil source and the other end is the land part. Alternatively, a plurality of hydraulic oil inlet passages opened in the groove portion and a plurality of hydraulic oil inlet passages, which are arranged on both sides in the circumferential direction of the hydraulic oil inlet passage, have one end open to the groove portion and the other end communicated with the hydraulic oil chamber of the pressure oil response device A valve sleeve having a hydraulic oil supply passage, and a valve sleeve inserted into the valve sleeve so as to be rotatable about the axis, and a plurality of axially extending grooves and lands are provided on the outer peripheral surface thereof. The valve sleeve has a plurality of hydraulic oil return passages that are alternately formed in the circumferential direction and open at the same groove or land portion at one end and communicate with the oil storage source at the other end. And the groove portion of the valve body and the land portion face each other, and The hydraulic oil supplied from the hydraulic oil flows into the hydraulic oil return passage, and when the valve body relatively rotates with respect to the valve sleeve from the neutral state, the valve sleeve and the land portion of the valve body are in sliding contact with each other to form the hydraulic oil inlet passage. The communication with the hydraulic oil return passage is cut off, and the hydraulic oil supplied from the hydraulic oil inlet passage is supplied from one of the hydraulic oil supply passages on both sides of the hydraulic oil inlet passage to one hydraulic oil chamber of the pressure oil response device. In the one configured as described above, in the land portion of the valve sleeve or the valve body,
When the relative rotational displacement amount of the valve body with respect to the valve sleeve from the neutral state exceeds preset different displacement positions, the valve body is sequentially communicated with the hydraulic oil inlet passage and the hydraulic oil chamber of the pressure oil response device. A hydraulic control valve, characterized in that a recess is formed to allow one of the hydraulic oil supply passages to flow into the hydraulic oil return passage.