JP2006248425A - Integral-type power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an integral-type power steering device which improves the mounting rigidity of a pin coming in contact with a sector gear. <P>SOLUTION: The integral-type power steering device comprises a control valve which supplies hydraulic oil selectively into a first pressure chamber and a second pressure chamber of a piston, and first/second valves which cause each of the first/second pressure chambers to communicate with the low pressure side when the inner pressure of the first/second pressure chambers is a given pressure or higher. The first valve or the second valve includes a valve body which can move in and out of a valve housing hole and has an axial hole, a valve seat which cuts off hydraulic oil flow, a pin member which is set in the axial hole of the valve body and is depressed when a steering wheel is turned to a limit to separate the valve body from the valve seat, a support member which has a plurality of supports that are formed at the outer periphery of the pin member to support a part of the outer periphery of the pin member and oil passages formed between the supports. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an integral type power steering apparatus that assists a driver's steering force with hydraulic pressure.

2. Description of the Related Art Conventionally, a valve provided in an integral type power steering apparatus has a pin, and the pin is pushed down by abutting against a sector gear to communicate pressure chambers on both sides of the piston. Thereby, the pressure on the assist side in the handle abutting state is reduced, and the burden on the apparatus when attempting to cut the handle further from the handle abutting state is reduced (for example, see Patent Document 1).
JP-A-4-65667

  However, in the above prior art, the length of the pin absorbs the processing error and assembly error of the member, so it is necessary to adjust the length in the assembled state, and the pin is completely fixed and supported. In addition, since an oil passage is provided around the pin, there is a problem that the mounting rigidity of the pin cannot be sufficiently ensured.

  The present invention has been made paying attention to the above problems, and an object of the present invention is to provide an integral type power steering apparatus in which the mounting rigidity of a pin abutting on a sector gear is improved.

  In order to achieve the above object, in the present invention, a housing, an input shaft connected to a steering wheel, a piston housed in the housing and separating the interior of the housing into a first pressure chamber and a second pressure chamber, A conversion mechanism that converts rotation of the input shaft into axial movement of the piston, and a control valve that selectively supplies hydraulic oil supplied from an external hydraulic source to the first pressure chamber and the second pressure chamber. And a transmission mechanism for transmitting the axial movement of the piston to the steering wheel, and provided on the inner wall of the housing so as to face the first pressure chamber. When the internal pressure of the first pressure chamber is equal to or higher than a predetermined pressure, A first valve that communicates the first pressure chamber with the low pressure side, and is provided on the inner wall of the housing so as to face the second pressure chamber. When the internal pressure of the second pressure chamber is equal to or higher than a predetermined pressure, the second pressure chamber Room A second valve that communicates with the pressure side, wherein the first valve or the second valve is provided with a valve housing having a valve housing hole, a valve body that is provided in the valve housing hole so as to be able to advance and retreat, and has an axial hole And a valve seat that shuts off the flow of hydraulic oil when the valve main body abuts, and is provided in an axial hole of the valve main body, and is pushed down when the steering wheel is in contact with the valve seat. A pin member that separates the valve body, a plurality of support portions that are provided on the outer peripheral side of the pin member and support a part of the outer periphery of the pin member, and are formed between the plurality of support portions And a support member provided with an oil passage.

  Therefore, it is possible to provide an integral type power steering device that secures the mounting rigidity of the pins that contact the sector gear.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for realizing an integral type power steering apparatus of the present invention will be described below based on an embodiment shown in the drawings.

[Overall configuration of integral power steering system]
Example 1 will be described with reference to FIGS. FIG. 1 is a side view of an integral type power steering apparatus 1, and FIG. 2 is an axial sectional view. For the sake of explanation, the axial direction of the input / output shafts 40 and 60 is defined as the y-axis, and the input shaft 40 side is positive.

  The integral type power steering device 1 meshes with the first housing 10 that houses a control valve that switches the assist direction, the second housing 20 that houses a piston 70 that generates an assist force by hydraulic pressure, A sector shaft 30 that rotates by reciprocating movement of the piston to steer the steered wheels.

  Further, in the present integral type power steering apparatus 1, first and second valves 100 and 200 as stroke limiters are provided. The first and second valves 100 and 200 are provided in the vicinity of the stroke end position of the sector shaft 30 and the piston 70, and are opened when an excessive hydraulic pressure in the apparatus or an excessive stroke occurs, and the hydraulic oil in the apparatus Is provided to prevent the sector shaft 30 and the piston 70 from interfering with the second housing 20.

  Both the first housing 10 and the second housing 20 are substantially cup-shaped members and are connected to each other in the axial direction opening. An input shaft 40 connected to the steering wheel is inserted into the bottom of the first housing 10 in the axial direction, and the piston 70 in the second housing 20 is slid in the axial direction by hydraulic pressure in accordance with the rotation of the input shaft 0. The first housing 10 is provided with an IN port 300 for supplying and discharging hydraulic oil and an OUT port (not shown).

  The second housing 20 and the sector shaft 30 are provided at right angles to each other in the axial direction. The teeth provided on the piston in the second housing 20 and the teeth provided on the sector shaft 30 mesh with each other. Steering assist is performed by rotating the shaft 30.

  A piston 70 is accommodated in the second housing 20 so as to be movable in the axial direction. By this piston 70, the second housing 20 is placed in the first oil chamber 21 on the input shaft side and the second oil chamber 22 on the cup-shaped bottom side. Separated while keeping liquid-tight. The first valve 100 in the second oil chamber 22 and at the bottom of the second housing 20 avoids excessive hydraulic pressure in the second oil chamber 22 and excessive stroke in the positive y-axis direction of the piston 70. Is provided.

  The input shaft 40 is connected to the output shaft 60 by a torsion bar 50. The output shaft 60 is inserted into the piston 70 in the axial direction, and is fitted to the piston 70 by a recirculating ball screw mechanism 61. Further, a piston tooth portion 71 carved in the circumferential direction is provided on the outer periphery of the piston 70, and the piston 70 meshes with the sector shaft 30 in the piston tooth portion 71.

  The second housing 20 is provided so that its axis is orthogonal to the sector shaft 30, and a sector shaft storage portion 23 for storing a part of the sector shaft 30 is provided in a part of the second housing 20 in the radial direction. The sector shaft storage portion 23 is supplied with hydraulic oil and communicates with the first oil chamber 21 to lubricate the sector shaft 30 and the piston tooth portion 71.

  In addition, a second valve 200 is provided at a portion of the sector shaft storage portion 23 in the positive y-axis direction. Here, the first valve 100 provided in the second oil chamber 22 has a function to avoid the piston 70 from excessive stroke in the negative y-axis direction, that is, the oil pressure in the first oil chamber 21 becomes excessive, and the sector shaft It has a function of avoiding an excessive stroke of 30 counterclockwise rotation directions.

  Accordingly, the second valve 200 is provided in the y-axis positive direction side portion of the sector shaft storage portion 23 to avoid an excessive stroke in the clockwise rotation direction of the sector shaft 30, thereby avoiding an excessive stroke in the positive y-axis direction of the piston 70. To do. Thereby, the y-axis bi-directional movement of the piston 70 and the excessive stroke of the sector shaft 30 in both rotational directions are avoided, and interference with the second housing 20 is avoided.

  The first oil chamber 21 in the second housing 20 communicates with the control valve 600 through a first oil chamber communication path (not shown) provided in the first housing 10, and the second oil chamber 22 includes the second housing 20 and The second oil chamber communication passage 16 provided across the first housing 10 communicates with the control valve 600.

  The control valve 600 functions as a rotary valve mechanism that introduces or discharges oil from the IN port 300 and the OUT port to the first and second oil chambers 21 and 22 according to the rotation of the input shaft 40.

[Valve details]
FIG. 3 is an axial sectional view and a front view of the first and second valves 100 and 200. The first and second valves 100 and 200 are members having the same configuration, and only the first valve 100 will be described below. The axial direction of the valve 100 is defined as the ξ axis, and the insertion side direction (see FIG. 2) to the second housing 20 is positive.

  The valve 100 includes a valve housing 110, a valve main body 120, a pin 130, a support member 140, and a spring 150. A valve housing 110, which is a bottomed cylindrical member, has a valve housing hole 111, and a valve main body 120, a pin 130, a support member 140, and a spring 150 are accommodated therein. Further, the valve housing hole 111 is communicated with the outside by an oil passage 112.

  The valve body 120 has a pin receiving hole 121 that is an axial through hole, and is inserted from the positive side of the ξ axis with respect to the valve housing 110 and is movably accommodated in the axial direction. Further, the outer peripheral portion at the end portion in the positive direction of the ξ axis is in contact with the support member 140 as the valve seat portion 122, and a base portion 123 serving as a base of the spring 150 is provided at the end portion in the negative direction of the ξ axis.

  The pin 130 is inserted into the pin receiving hole 121 of the valve main body 120 and is fitted to the valve main body 120 with its axial direction regulated. On the other hand, the support member 140 is inserted into the inner peripheral surface 141 so as to be axially slidable. During assembly, the ξ-axis positive direction end 131 is fitted into the pin receiving hole 121 so as to be exposed from the ξ-axis positive direction end of the support member 140.

  The support member 140 is a cylindrical member. The support member 140 is fixedly supported on the outer peripheral surface 142 at the end of the valve housing 110 in the ξ-axis positive direction, and the inner peripheral surface 141 is configured to regulate the radial movement of the pin 130 while being restricted. It is slidable in the direction.

  A plurality of axial grooves 143 are provided on the inner peripheral surface 141, and both ends of the ξ axis of the support member 140 are communicated by the grooves 143 when the pin 130 is fitted, and also communicated with the outer periphery of the valve body 120. It becomes. The outermost peripheral portion of the groove 143 is located on the inner peripheral side of the valve seat portion 122 of the valve main body 120.

  In the support member 140, the length of the inner peripheral surface 141 in the ξ-axis direction is smaller than that of the outer peripheral surface 142, and a tapered surface 144 is formed between the inner peripheral surface 141 and the outer peripheral surface 142. Therefore, when the valve body 120 is in contact with the valve seat portion 122, the taper surface 144 is in contact with the valve seat portion 122, and the groove 143 provided in the inner peripheral surface 141 communicates with the outer periphery of the valve body 120. Is blocked by contact.

  The spring 150 is regulated in the ξ-axis direction by the bottom 113 of the valve housing 110 and the pedestal 123 of the valve main body 120, and urges the valve main body 120 in the positive ξ-axis direction.

  Therefore, at the normal time, the valve main body 120 and the support member 140 abut on the valve seat 122 and the tapered surface 144, and the outer periphery of the groove 143 and the valve main body 120 is blocked. Further, if the pin 130 is pressed in the negative ξ axis direction against the urging force of the spring 150 and the valve body 120 fitted to the pin 130 moves in the negative ξ axis direction, the groove 143 and the outer periphery of the valve housing 110 communicate with each other. Is done.

  Since the outer periphery of the valve body 120 and the outer periphery of the valve housing 110 are communicated by the oil passage 112, the groove 143 of the support member 140 and the outer periphery of the valve housing 110 are also communicated / blocked as the valve body 120 and the support member 140 are separated / abutted. Is done. Thus, the valve 100 functions as a normally closed valve that communicates / blocks the ξ axis positive direction side of the support member 140 and the outer periphery of the valve housing 110.

[Details of support member]
4A and 4B are an axial front view and a radial sectional view of the support member 140, respectively. FIG. 4B shows an AA cross section of FIG.

  As described above, the arc-shaped groove 143 is provided on the inner peripheral surface 141 of the support member 140, and a portion where the groove 143 is not provided supports the pin 130 slidably in the axial direction as the support portion 145. In the embodiment of the present application, four grooves 143 are provided at equal intervals on the inner peripheral surface 141, but it is sufficient that the hydraulic oil communicates smoothly between both ends in the ξ-axis direction of the support member 140. The number and shape are not particularly limited.

  Further, as described above, the outermost peripheral portion of the groove 143 is located on the inner peripheral side with respect to the valve seat portion 122 of the valve body 120, and the contact position D with the valve seat portion 122 becomes the tapered surface 144. When the valve seat 122 is not in contact, that is, when the valve 100 is opened, the groove 143 is not in contact with the outer peripheral side of the groove 143 in the tapered surface 144 so that the groove 143 is not blocked by the valve body 120.

[Contrast between the effect of the prior art and the embodiment of the present application]
FIG. 5 is an axial sectional view and a front view of the valve 100 ′ in the conventional example, and FIG. 6 is an axial front view and a radial sectional view of the supporting member 140 ′ in the conventional example. The valve 100 'provided in the conventional integral type power steering apparatus is pushed down by the pin 130' coming into contact with the sector gear, and the pressure chambers on both sides of the piston are communicated with each other. This reduces the burden on the device when attempting to cut the handle further from the handle-striking state.

  However, since the length of the pin 130 ′ absorbs the processing error and assembly error of the member, it is necessary to adjust the length in the assembled state, and the pin 130 ′ is completely fixed to the support member 140 ′. Cannot be supported.

  Further, an oil passage 141 ′ provided on the inner periphery of the support member 140 ′ is provided around the pin 130 ′, and this oil passage 141 ′ is provided over the entire inner periphery of the support member 140 ′. There is a problem that a clearance corresponding to the oil passage 141 ′ is generated between the pin 130 ′ and the support member 140 ′, and the mounting rigidity of the pin 130 ′ cannot be sufficiently ensured.

  On the other hand, in the present embodiment, the pin 130 is inserted into the pin receiving hole 121 of the valve main body 120 and is fitted to the valve main body 120 with its axial direction being restricted, while being fitted to the inner peripheral surface 141 of the support member 140. On the other hand, it was inserted so as to be slidable in the axial direction. The support member 140 is a cylindrical member, and is fixedly supported on the outer circumferential surface 142 at the end of the valve housing 110 in the ξ axis positive direction, and the inner circumferential surface 141 is slidable in the axial direction while restricting the radial movement of the pin 130. It was decided to be stored.

  In addition, an arc-shaped groove 143 is provided on the inner peripheral surface 141 of the support member 140, and a portion where the groove 143 is not provided supports the pin 130 as a support portion 145 so as to be slidable in the axial direction. The outermost peripheral part was provided so as to be located on the inner peripheral side with respect to the valve seat part 122 of the valve main body 120. That is, the groove 143 is not in contact with the outer peripheral side of the groove 143 on the tapered surface 144 so that the groove 143 is not blocked by the valve body 120 when the valve 100 is opened.

  As a result, it is possible to support the pin 130 at the support portion 145 on the inner peripheral surface 141 while communicating the both end surfaces of the ξ axis of the support member 140 with the axial groove 143, and ensure the flow passage cross-sectional area of the hydraulic oil. However, the pin 130 can be reliably supported and the mounting rigidity can be ensured.

  In addition, since it is not necessary to provide a special support portion for the pin 130, the pin 130 can be a simple cylinder, and the degree of freedom of adjustment of the mounting position can be increased and retracted with respect to the pin receiving hole 121 of the valve body 120. It is possible to avoid being suppressed.

  The second embodiment will be described with reference to FIGS. 7 is a support member 140a according to the second embodiment, and FIG. 8 is a cross-sectional view taken along the line BB of FIG. Since the basic configuration is the same as that of the first embodiment, only different points will be described. In the support member 140 of Example 1, an arc-shaped groove 143 was formed on the inner peripheral surface 141 to secure a flow path area, and the pin 130 was supported by the support portion 145.

  On the other hand, in Example 2, the pin 130 is supported by the support portion 145a protruding in the inner diameter direction from the inner peripheral surface 141a, and the flow path area is secured by the groove portion 143a in which the support portion 145a is not provided on the inner peripheral surface 141a. This is different from the first embodiment. Note that the number of the support portions 145a is not particularly limited as long as the number of the support portions 145a is two or more as long as the channel area can be secured. Moreover, the contact position D with the valve seat part 112 of the valve housing 110 is provided in the outer peripheral side rather than the internal peripheral surface 141a like Example 1. FIG.

  In the second embodiment, the pin 130 is supported by the support portion 145a of the support member 140 so as to be slidable in the axial direction. In the groove portion 143a in which the support portion 145a is not provided on the inner peripheral surface 141a, a clearance is formed between the pin 130 and the inner peripheral surface 141a, and the flow path area is secured by the clearance of the groove portion 143a, so that the first embodiment can be realized. The same effect can be obtained.

  A third embodiment will be described with reference to FIGS. FIG. 9 is a sectional view in the axial direction of the valve 100 in the third embodiment, and FIG. 10 is a sectional view of the supporting member 140b in the third embodiment and its CC line. The basic configuration of the third embodiment is the same as that of the first embodiment. In the third embodiment, a cylindrical support portion 145b is provided further on the inner peripheral side than the inner peripheral surface 141b of the support member 140, and the pin 130 is supported by the support portion 145b.

  Further, the support portion 145b is supported by a rib 143b protruding from the inner peripheral surface 141b. The number of ribs 143b is three at equal intervals in the circumferential direction, but the number is not limited as long as the flow path area is secured. Similar to the first embodiment, the contact position D of the valve housing 110 with the valve seat 112 is provided on the outer peripheral side with respect to the inner peripheral surface 141b.

  Even in the third embodiment, the pin 130 is supported by the cylindrical support portion 145b so as to be slidable in the axial direction, and the flow path area of the hydraulic oil is ensured in the clearance between the support portion 145b and the inner peripheral surface 141b. The same effects as those of the first embodiment can be obtained.

[Other embodiments]
As described above, the best mode for carrying out the present invention has been described based on the first embodiment and the second embodiment. However, the specific configuration of the present invention is not limited to each embodiment. Design changes and the like within a range that does not depart from the gist are also included in the present invention.

1 is a side view of an integral type power steering device in Embodiment 1. FIG. 1 is an axial sectional view of an integral type power steering device according to Embodiment 1. FIG. It is the axial sectional view and front view of the 1st and 2nd valve | bulb in Example 1. FIG. It is the axial front view and radial direction sectional view of the support member in Example 1. It is an axial sectional view and a front view of a valve in a conventional example. It is the axial direction front view of the supporting member in a prior art example, and its radial direction sectional drawing. FIG. 6 is an axial cross-sectional view and a front view of first and second valves in Embodiment 2. It is the axial direction front view and radial direction sectional drawing of the support member in Example 2. FIG. FIG. 6 is an axial cross-sectional view and a front view of first and second valves in Embodiment 3. It is the axial direction front view and radial direction sectional view of the supporting member in Example 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Integral type power steering device 10 1st housing 20 2nd housing 23 Sector shaft storage part 30 Sector shaft 40 Input shaft 50 Torsion bar 60 Output shaft 70 Piston 71 Piston tooth part 100,200 1st, 2nd valve 110 Valve housing 111 Valve housing hole 112 Oil passage 113 Bottom 120 Valve body 121 Pin receiving hole 122 Valve seat 123 Pedestal 130 Pin 131 ξ axis positive direction end 140 Support member 141 Inner peripheral surface 142 Outer peripheral surface 143 Groove 144 Tapered surface 145 Support Part 150 Spring

Claims (1)

A housing;
An input shaft connected to the steering wheel;
A piston housed in the housing and separating the interior of the housing into a first pressure chamber and a second pressure chamber;
A conversion mechanism that converts rotation of the input shaft into axial movement of the piston;
A control valve for selectively supplying hydraulic oil supplied from an external hydraulic source to the first pressure chamber and the second pressure chamber;
A transmission mechanism for transmitting the axial movement of the piston to the steering wheel;
A first valve that is provided on the inner wall of the housing so as to face the first pressure chamber, and that communicates the first pressure chamber with the low pressure side when the internal pressure of the first pressure chamber is equal to or higher than a predetermined pressure;
A second valve that is provided on the inner wall of the housing so as to face the second pressure chamber and communicates with the low pressure side when the internal pressure of the second pressure chamber is equal to or higher than a predetermined pressure;
The first valve or the second valve is
A valve housing having a valve receiving hole;
A valve body provided in the valve housing hole so as to be movable back and forth, and having an axial hole;
A valve seat that shuts off the flow of hydraulic oil by contacting the valve body;
A pin member that is provided in an axial hole of the valve body, and is pushed down when the steering wheel is in contact with the valve body to separate the valve body from the valve seat;
A support member provided on the outer peripheral side of the pin member, and comprising a plurality of support portions for supporting a part of the outer periphery of the pin member; and an oil passage formed between the plurality of support portions; An integral type power steering device characterized by comprising:

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