JP2002293255A - Steering damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive steering damper that has a simple structure and a high assembling property. SOLUTION: This steering damper comprises a power cylinder 10 for generating a wheel steering force with working oil pressure guided through a hydraulic pipe 22 and a connector housing 40 for connecting the hydraulic pipe 22 to the power cylinder 10. First and second ports 48 and 49 for connecting the power cylinder 10 to the hydraulic pipe 22 are formed in parallel in the connector housing 40, the first port 48 has a first check valve 31 opening for a working fluid flowing into the power cylinder from the hydraulic pipe 22, and the second port 49 has a second check valve 32 opening for the working fluid flowing out of the power cylinder 10 to the hydraulic pipe 22. The connector housing 40, the first check valve 31 and the second check valve 32 constitute a damper unit 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering damper provided in a power steering device of a vehicle.

[0002]

2. Description of the Related Art Conventionally, as this type of steering damper, for example, there is one disclosed in Japanese Utility Model Publication No. 2-49109.

[0003] To explain this, a steering damper includes a power cylinder that generates a steering force of wheels by operating hydraulic pressure guided through a hydraulic pipe, a control valve that switches the flow of hydraulic oil to the power cylinder, and a control valve from the power cylinder to the control valve. A first check valve is opened for the hydraulic oil being guided, and a second check valve is opened for the hydraulic oil guided from the control valve to the power cylinder. The first check valve and the second check valve are interposed in the middle of the hydraulic piping.

When the rack shaft of the power cylinder causes minute vibration in the axial direction, a small amount of hydraulic oil corresponding to the amount of movement moves in and out of the power cylinder, and the first check valve and the second check valve pass through the power cylinder. It gives resistance to the flow of oil and suppresses the roll vibration, so-called shimmy, that occurs in the steering system.

[0005]

However, such a conventional steering damper has a structure in which the first check valve and the second check valve constituting the steering damper are interposed in the middle of the hydraulic piping. In addition to the need for a bracket for supporting the first check valve and the second check valve on the vehicle body and the fact that the first check valve and the second check valve are coaxially arranged with each other, the steering damper itself is not required. However, there has been a problem that the structure and the assembling property of the device become complicated and the device becomes expensive.

The present invention has been made in view of the above problems, and has as its object to provide an inexpensive steering damper which has a simple structure, is easy to assemble, and is easy to assemble.

[0007]

According to a first aspect of the present invention, there is provided a power cylinder for generating a steering force of a wheel by operating hydraulic pressure guided through a hydraulic pipe, and a connector housing for connecting the hydraulic pipe to the power cylinder. The first and second ports that connect the power cylinder and the hydraulic pipe are formed in parallel, and the first port is provided with a first check valve that opens for hydraulic oil flowing into the power cylinder from the hydraulic pipe. In addition, the second port is provided with a second check valve that opens for hydraulic oil flowing from the power cylinder to the hydraulic pipe, and the damper unit is connected to the connector housing, the first check valve, and the second check valve. Is constituted.

According to a second aspect of the present invention, in the first aspect, the damper unit is provided with a fixed orifice for constantly communicating the hydraulic pipe and the power cylinder.

In a third aspect based on the first or second aspect, the first and second check valves are a valve housing fitted to the first and second ports, a valve seat fixed to the valve housing, A valve seated on the valve seat,
A spring for pressing the valve against the valve seat is provided.

According to a fourth aspect of the present invention, in the third aspect, a fixed orifice is provided for constantly communicating the power cylinder and the hydraulic pipe, and a fixed orifice is formed in at least one of the first and second check valves. The feature was adopted.

In a fifth aspect based on any one of the first to fourth aspects, the first and second ports are formed so as to be substantially orthogonal to a cylinder tube of the power cylinder.
The first and second check valves are arranged so as to be substantially orthogonal to the cylinder tube and arranged at positions adjacent to each other.

In a sixth aspect based on any one of the first to fourth aspects, the first and second ports are formed so as to be substantially orthogonal to a cylinder tube of the power cylinder.
The first and second check valves are arranged so as to be substantially orthogonal to the cylinder tube, and are arranged so as not to be adjacent to each other and so as not to interfere with each other.

[0013]

According to the first aspect of the present invention, even when a kickback of minute vibration is input to the rack axis of the power cylinder in the axial direction, a small amount of hydraulic oil corresponding to the force is applied between the hydraulic pipe and the power cylinder. Although the first check valve and the second check valve provide resistance to the flow of hydraulic oil passing therethrough, the flow of a small amount of hydraulic oil between the hydraulic piping and the power cylinder can be suppressed, As a result, the shimmy is suppressed and the steering feeling is improved.

The damper unit is housed in the connector housing, and has a simple structure because the first and second ports for ensuring the flow of hydraulic oil in only one direction between the hydraulic pipe and the power cylinder are formed in parallel. Since the vehicle is supported by the vehicle body via the power cylinder, it is not necessary to newly provide a bracket or the like for supporting the damper unit on the vehicle body, and it is possible to provide a steering damper that can be easily mounted.

Since the first check valve and the second check valve are housed in parallel in the connector housing to constitute the damper unit, the damper unit can be realized with a simple structure, and assembling is facilitated accordingly, and productivity is improved. Without compromising.

Since the first and second check valves are interposed in the first and second ports, respectively, the unitized first and second check valves can be used, and the cost of the damper unit can be reduced. At the same time, by simply changing the combination of the specifications of the first and second check valves, it is possible to easily cope with the change of the specification setting of the damper unit without changing the connector housing.

According to the second aspect of the present invention, the fixed orifice always communicates the power cylinder and the hydraulic pipe, so that responsiveness at the time of sudden steering is ensured, the vacuum phenomenon of the power cylinder is suppressed, and the steering feeling is improved. It is not spoiled.

According to the third aspect of the present invention, the first and second check valves have a structure in which a valve seat and a valve are housed in a valve housing to form a unit. It is possible to assemble the second port by press fitting etc., and it is easy to assemble the parts of the damper unit, and only by changing the combination of the specifications of the first and second check valves, without changing the connector housing, It can easily respond to changes in the specification settings of the damper unit.

According to the fourth aspect of the present invention, since the fixed orifice is opened in at least one of the first check valve and the second check valve, the structure of the damper unit due to the provision of the fixed orifice can be avoided, and the damper unit can be prevented. Can be made more compact.

According to the fifth aspect, the first and second check valves are arranged in the connector housing at positions adjacent to each other in parallel, so that the amount of protrusion of the connector housing with respect to the power cylinder is suppressed, and The degree of freedom of the arrangement is dramatically improved.

According to the sixth aspect, the first and second check valves are arranged in parallel in the connector housing and are arranged at positions not adjacent to each other, so that the connector housing can be further downsized. Therefore, the degree of freedom in arrangement when mounted on a vehicle is dramatically improved.

[0022]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, in the steering apparatus 1 of the vehicle, the rotation of the steering shaft 16 moves the rack shaft 12 in the left-right direction via a steering gear 21 constituted by a rack and pinion type gear (not shown). The wheels are steered via tie rods (not shown) connected to both ends of the rack shaft 12.

As a power steering mechanism for assisting the steering force, a control valve 20 composed of a valve (not shown) for switching the flow of pressure oil in conjunction with the steering shaft 16 and a rack using pressure oil guided through the control valve 20 are provided. And a power cylinder 10 for driving the shaft 12. The rack shaft 12 moves in the axial direction by the force from the steering shaft 16 and the assisting force of the power cylinder 10.

The power cylinder 10 includes left and right mounting portions 10.
a cylinder tube 11 fixed to the vehicle body via a and 10b, a rack shaft 12 slidably supported on the inner peripheral surface of the cylinder tube 11, and a piston 13 fixed in the middle of the rack shaft 12. And the piston 13
Thereby, the oil chambers 14 and 15 are partitioned in the cylinder tube 11.

FIG. 2 shows a hydraulic circuit constituting a power steering mechanism. A control valve 20 connects passages L ₁ and L ₂ connected to the oil chambers 14 and 15 to a hydraulic pump P and a tank T, respectively, according to the steering direction. It is to communicate.

As a steering damper for attenuating the vibration of the rack shaft 12, a damper unit 30 is interposed in each of the passages L ₁ and L ₂ . These damper unit 30 is provided with a first check valve 31 and the second check valve 32 and fixed orifice 33, it is disposed in parallel to the path L _1, L _2.

As shown in FIG. 3, the damper unit 30 includes a connector housing 40 for connecting the hydraulic pipe 22 to the cylinder tube 11, and a first check valve 31 and a second check valve 31 that constitute the damper unit 30 in the connector housing 40. The two-check valve 32 and the fixed orifice 33 are housed.

A boss 23 is fixed to the outer periphery of the cylinder tube 11, and a connector housing 40 is fastened to the boss 23. The bottomed cylindrical boss 23 has a bottom 24 fixed to the outer periphery of the cylinder tube 11.
A through hole 26 communicating with the oil chamber 14 is formed in the oil chamber 14. A hole 19 that opens into the oil chamber 14 is formed in the cylinder tube 11, and this hole 19 communicates with the through hole 26 of the oil chamber 14.

The bottomed cylindrical boss 23 has a cylindrical portion 25 that rises from the bottom portion 24, and a screw hole 27 for screwing the connector housing 40 is formed on the inner periphery of the cylindrical portion 25.

The cylindrical connector housing 40 has a male screw portion 41 screwed into the screw hole 27 of the boss 23, and is fastened to the cylinder tube 11 via the boss 23. A packing 42 is interposed between the boss 23 and the connector housing 40, and the threaded portion is sealed. This boss 2
The sealing structure between the connector housing 3 and the connector housing 40 is not limited to the packing 42, but may be an O-ring or the like.

A ring-shaped pipe joint 43 to which the hydraulic pipe 22 is connected is fastened to the upper end of the connector housing 40 via a connector bolt 44. Connector housing 40
Has a through hole 4 communicating with a through hole 51 in the connector bolt 44.
5 are formed. The through hole 45 is disposed coaxially with the through hole 26 of the boss 23 and the through hole 19 of the cylinder tube 11.

First and second ports 48, 49 connecting the power cylinder 10 and the hydraulic pipe 22 to the connector housing 40.
Are formed in parallel. The first and second ports 48 and 49 are formed side by side so as to be substantially perpendicular to the central axis O of the cylinder tube 11.

A through hole 46 is formed in the connector housing 40 and communicates with the first and second ports 48 and 49 and also communicates with the through hole 45. The open end of the through hole 46 is closed by a ball 47. It is. Thus, the first and second ports 48 and 49 constitute an oil passage communicating with the pipe 22 via the through hole 46, the through hole 45, the through hole 51 in the connector bolt 44, and the ring-shaped pipe joint 43. Will be.

The end surface of the connector housing 40 and the boss 23
A gap 28 is formed between the bottoms 24 of the two. The first and second ports 48 and 49 are provided with the gap 28, the through hole 26, and the through hole 19, respectively.
Through the oil chamber 14.

The first port 48 is provided with a first check valve 31 for opening the hydraulic oil flowing into the power cylinder 10 from the hydraulic pipe 22, and the second port 49 is provided with a first check valve 31 from the power cylinder 10 to the hydraulic pipe 22. A second check valve 32 that opens for the hydraulic oil flowing into the valve is interposed. These first and second check valves 31 and 32 are connected to the cylinder tube 11.
And the first and second check valves 31, 32 are adjacent to each other. That is, the first and second check valves 3
The reference numerals 1 and 32 are disposed at substantially the same position in a direction substantially perpendicular to the center axis O of the cylinder tube 11 (the vertical direction in FIG. 3), and the amount of protrusion of the connector housing 40 from the cylinder tube 11 is suppressed.

The first check valve 31 has a cylindrical valve housing 61 formed by pressing and a valve seat 62 fixed to the valve housing 61 by swaging.
A valve 63 seated on the valve seat 62; and a spring 64 for pressing the valve 63 against the valve seat 62. The biasing force of the spring 64 is a force in the direction of preventing the hydraulic oil from flowing from the power cylinder 10 side to the hydraulic pipe 22 side, so that the valve 63 does not separate from the valve seat 62 due to vibration or its own weight, and
It is set so that the damping characteristic of the hydraulic oil flowing into the power cylinder 10 from the hydraulic pipe 22 required to be zero can be obtained.

In this embodiment, the valve 63 has a hole that forms the fixed orifice 33. The opening diameter of the fixed orifice 33 is arbitrarily set according to the damping characteristics required for the damper unit 30. Valve 63
By forming the fixed orifice 33 at the bottom, the structure can be simplified.

The fixed orifice 33 obtains a target damping characteristic by the synergistic action of the first check valve 31 and the second check valve 32. As a result, the pressure oil is
, The pressure oil between the power cylinder 10 and the hydraulic pipe 22 must flow earlier than the timing when the first check valve 31 and the second check valve 32 are opened. This is to ensure that. Therefore, the fixed orifice 33 does not necessarily need to be provided on the valve 63 of the first check valve 31, and may be provided on the valve 73 side of the second check valve 32, or may have holes having a function equivalent to that of the fixed orifice 33. Port 4
It may be formed at a position parallel to 8, 49. In addition, there is no problem if two orifices provided in both the valve 63 of the first check valve 31 and the valve 73 of the second check valve 32 have the same function as one fixed orifice 33.

The valve housing 61 and the valve seat 62
The first check valve 31 and the valve 63 are formed as a single component by being formed by press working and being assembled in advance.

The second check valve 32 has a cylindrical valve housing 71 formed by press working, and a valve seat 72 fixed to the valve housing 71 by swaging.
A valve 73 seated on the valve seat 72; and a spring 74 for pressing the valve 73 against the valve seat 72. The biasing force of the spring 74 is a force in the direction of preventing the hydraulic oil from flowing from the hydraulic pipe 22 to the power cylinder 10, as opposed to the spring 64 of the first check valve 31. It is set so as not to be separated from the valve seat 72 and to obtain the damping characteristic of the hydraulic oil flowing into the hydraulic pipe 22 from the power cylinder 10 required for the damper unit 30.

The damper unit 30 connected to the oil chamber 15 has the same structure as the damper unit 30 connected to the oil chamber 14 described above.

The operation of the embodiment of the present invention configured as described above will now be described.

When the vehicle is traveling straight, the control valve 20
Is held at the neutral position, the hydraulic oil discharged from the pump P is returned to the tank T via the control valve 20, and the discharge pressure of the pump P is guided to both the oil chambers 14 and 15, so that the power cylinder 10 Does not generate steering assist force. At this time, the hydraulic pipe 22 and the power cylinder 1
There is almost no flow of hydraulic oil between 0, and the first and second check valves 31, 32 are closed.

When the kickback of the minute vibration from the wheel is input, when the rack shaft 12 generates a minute vibration in the axial direction, a small amount of hydraulic oil corresponding to the minute movement amount is supplied to each oil chamber. At this time, most of the hydraulic oil flowing between the hydraulic pipe 22 and the power cylinder 10 tries to pass through the first and second check valves 31 and 32 by bypassing the fixed orifice 33 having a small opening area. I do. However, the first and second check valves 3 of the damper unit 30
1 and 32 suppress the minute vibration of the rack shaft 12 by imparting resistance to the flow of the hydraulic oil accompanying the minute vibration of the rack shaft 12, and suppress the roll vibration, so-called shimmy, generated on the steering wheel, thereby improving the steering feeling. Enhanced.

At the time of normal steering, hydraulic oil accompanying the operation of the steering wheel flows by opening the first check valve 31 or the second check valve 32.

When the vehicle turns right, the steering shaft 1
The position of control valve 20 by rotation of 6
Is switched, the hydraulic oil discharged from the pump P passes through.
Road L ₁Through the fixed orifice 33 and the first check valve
It flows into the oil chamber 14 via 31. On the other hand, the oil chamber 15
Hydraulic oil passes through the fixed orifice 33 and the second check valve 32
Outflow, passage L_TwoThrough the control valve 20
Is returned to the tank T. As a result, the power
The rack 10 moves the rack shaft 12 rightward in the drawing.
The steering assist force is applied.

When the vehicle turns left, the steering shaft 1
The position of control valve 20 by rotation of 6
Is switched, the hydraulic oil discharged from the pump P passes through.
Road L _TwoThrough the first check with fixed orifice 33
The oil flows into the oil chamber 15 via the valve 31. On the other hand, the oil chamber 14
Hydraulic oil passes through the fixed orifice 33 and the second check valve 32
And outflow, passage L₁Through control valve 2
It is returned to the tank T via 0. This allows the power system
The Linda 10 moves the rack shaft 12 to the left in the figure.
To the steering assist force.

In FIG. 3, when the first check valve 31 is opened, the operating oil from the hydraulic pipe 22 is supplied to the ring-shaped pipe joint 4.
3, through hole 51 of connector bolt 44, through hole 45 of connector housing 40, through hole 46, first port 48, gap 2
8. The oil flows into the oil chambers 14 and 15 through the through holes 26 and the holes 19. On the other hand, when the second check valve 32 is opened, the oil chamber 14,
Hydraulic oil from the pipe 15 passes through the hole 19, the through hole 26, the gap 28, the second port 49, the through hole 46, the through hole 45, the through hole 51 of the connector bolt 44, the ring-shaped pipe joint 43, and the hydraulic pipe 22.
Spills to the side.

At the time of sudden steering performed for emergency avoidance or the like, the hydraulic oil flows through the fixed orifice 33 before the first and second check valves 31 and 32 are opened, so that the rack shaft is synchronized with the operation of the steering wheel. 12 can be moved, and high steering responsiveness is secured.

In all the operating conditions (1) to (5), the fixed orifice 33 constantly communicates between the hydraulic pipe 22 and the power cylinder 10, so that the vacuum phenomenon of the power cylinder 10 is suppressed and the steering feeling is not impaired.

Since the damper unit 30 is housed in the connector housing 40 and supported by the vehicle body via the power cylinder 10, it is not necessary to newly provide a bracket or the like for supporting the damper unit 30 on the vehicle body.

In the connector housing 40, the first check valve 31, the second check valve 32 and the fixed orifice 33
And the damper unit 30 is configured so that the number of components can be minimized, and the damper unit 30 can be easily assembled to the power cylinder 10.
That is, in the assembly line of the power cylinder 10, the connector housing 4 is attached to the boss 23 of the cylinder tube 11.
The damper unit 30 is assembled by screwing
Is completed, the increase in assembling time can be suppressed, and productivity can be maintained.

The first and second check valves 31 and 32 are respectively provided in valve housings 61 and 71 with valve seats 62 and 7 respectively.
2. The first and second check valves 31 and 32 are installed in the first and second ports 48 and 49 of the connector housing 40 because of the unitized structure in which the valves 63 and 73 and the springs 64 and 74 are housed. The damper unit 30 can be easily assembled by press-fitting, and the cost can be reduced. That is, in the assembly line of the damper unit 30, the connector housing 40
By mounting the first and second check valves 31 and 32 by assembling the valve housings 61 and 71 with a screw connection or the like, an increase in assembling time can be suppressed, and productivity can be maintained.

Further, by simply changing the combination of the specifications of the first and second check valves 31, 32, the specification of the damper unit 30 can be easily changed without changing the connector housing 40 at all. .

The first and second check valves 31 and 32 are arranged side by side so as to be substantially perpendicular to the center axis O of the cylinder tube 11.
1 and 32 are arranged adjacent to each other, so that the cylinder tube 11 of the connector housing 40 is
And the degree of freedom in mounting the power steering device on the vehicle is greatly improved. As a result, the restriction on the connection structure of the hydraulic pipe 22 to the connector housing 40 is suppressed, and the cost increase of the product using the special connection structure is avoided.

Next, another embodiment shown in FIG. 4 will be described. The same components as those in the above-described embodiment are denoted by the same reference numerals.

The first and second check valves 31 and 32 are arranged so as to be substantially perpendicular to the central axis O of the cylinder tube 11, and the first and second check valves 31 and 32 are not adjacent to each other. It is arranged so as not to interfere with the space. Thus, the first and second ports 48, 49
By making the oil passages close to each other so as not to interfere with each other, the outer diameter of the connector housing 40 can be reduced, and the connector housing 40 can be made more compact, and the power steering device can be mounted on a vehicle. The degree of freedom is dramatically improved.

It is apparent that the present invention is not limited to the above-described embodiment, and that various changes can be made within the scope of the technical idea.

[Brief description of the drawings]

FIG. 1 is a front view of a power steering device according to an embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram of the power steering device.

FIG. 3 is a sectional view of a damper unit and the like.

FIG. 4 is a sectional view of a damper unit and the like showing another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power steering device 10 Power cylinder 20 Control valve 22 Hydraulic piping 30 Damper unit 31 First check valve 32 Second check valve 33 Fixed orifice 40 Connector housing 48 First port 49 Second port 61 Valve housing 62 Valve seat 63 Valve 64 Spring 71 Valve Housing 72 Valve Seat 73 Valve 74 Spring

 ──────────────────────────────────────────────────続 き The continuation of the front page F term (reference) 3D033 DC02

Claims (6)

[Claims] 1. A power cylinder for generating a steering force of a wheel by operating hydraulic pressure guided through a hydraulic pipe, and a connector housing for connecting a hydraulic pipe to the power cylinder, wherein the power cylinder and the hydraulic pipe are connected within the connector housing. The first and second ports are formed in parallel, the first port is provided with a first check valve that opens for hydraulic oil flowing into the power cylinder from hydraulic piping, and the second port is provided with a power cylinder A second check valve that opens for hydraulic oil flowing out of the hydraulic pipe from the connector housing, and a damper unit comprising the connector housing, the first check valve, and the second check valve. . 2. The steering damper according to claim 1, wherein the damper unit includes a fixed orifice for constantly communicating the hydraulic pipe and the power cylinder. 3. The first and second check valves include a valve housing fitted to the first and second ports, a valve seat fixed to the valve housing, a valve seated on the valve seat, and a valve connected to the valve. The steering damper according to claim 1, further comprising a spring that presses the seat. 4. The apparatus according to claim 3, further comprising a fixed orifice that constantly connects the power cylinder and the hydraulic pipe, wherein a fixed orifice is formed in at least one of the first and second check valves. Steering damper. 5. The first and second ports are formed so as to be substantially orthogonal to a cylinder tube of the power cylinder, and the first and second check valves are arranged so as to be substantially orthogonal to the cylinder tube. The steering damper according to any one of claims 1 to 4, wherein the dampers are arranged at positions adjacent to each other. 6. The first and second ports are formed so as to be substantially orthogonal to a cylinder tube of the power cylinder, and the first and second check valves are arranged so as to be substantially orthogonal to the cylinder tube. The steering damper according to any one of claims 1 to 4, wherein the steering dampers are arranged so as not to be adjacent to each other and so as not to interfere with each other.