JP2000127996A - Hydraulic power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely damp the vibration generated between a member on rotor side and a member on valve body side and stably maintain high vibration damping performance for a long time. SOLUTION: A stub shaft 1 and a pinion shaft 2 are mutually connected through a torsion bar 7. A space part 16 facing a rotor 13 part of the stub shaft 1 is formed in the pinion shaft 2, and hydraulic fluid is filled in this space part 16. A blade 18 partitioning the inside of the space part 16 into two fluid chambers 19A, 19B is protrusively provided in the rotor 13 part, and a clearance 20 between the blade 18 and an inner wall 16a of the space part 16 is used as a restriction passage. When the torsion bar 7 is twisted, the blade 18 turns in the space part 16 and hydraulic fluid passes through the clearance 20 at this time. The vibration between a member on rotor side and a member on valve body side is damped by restriction resistance generated when hydraulic fluid passes through the clearance 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic power steering apparatus having a rotary valve for controlling a hydraulic pressure supplied to a power cylinder for steering, and more particularly to an improvement for reducing vibration of a rotary valve portion. Power steering device.

[0002]

2. Description of the Related Art In a hydraulic power steering apparatus, an input side shaft and an output side shaft are connected by a torsion bar, and the output of a steering power cylinder is controlled by using the torsion of the torsion bar. As a control valve for controlling the power cylinder,
There are a so-called rotary type and a spool type, among which a rotary type control valve (referred to as a rotary valve in this specification) is provided with a rotor provided on an input side shaft and a rotor provided on an output side shaft. When the rotor and the valve body rotate relative to each other in response to the torsion of the torsion bar, the valve grooves formed between the valve body and the right cylinder circuit and the left cylinder circuit of the power cylinder are formed. The supply hydraulic pressure for the is appropriately adjusted.

However, this type of power steering device has a basic structure in which a rotor-side member and a valve body-side member are connected by a torsion bar having a spring characteristic. When the twist is released, vibration occurs between the rotor-side member and the valve body-side member, and this vibration is transmitted to a steering gear or the like, causing a problem that unpleasant noise is generated for the occupant.

To cope with this, a power steering apparatus as disclosed in Japanese Patent Application Laid-Open No. 8-318869 has been proposed. In this power steering device, a rubber material is interposed between a rotor-side member and a valve body-side member, and the rubber material is elastically deformed when the rotor-side member and the valve body-side member rotate relatively with the torsion bar. Thus, the vibration between the two is attenuated.

[0005]

However, in this conventional power steering apparatus, the vibration between the rotor side member and the valve body side member is attenuated by the elasticity of the rubber material and its internal resistance. Therefore, it is considered that the rubber material is liable to deteriorate relatively early due to the use over time, and the vibration damping function is deteriorated due to the deterioration.

Therefore, the present invention can reliably attenuate the vibration generated between the rotor side member and the valve body side member, and maintain its high damping performance stably for a long period of time. It is an object of the present invention to provide a hydraulic power steering device that can be used.

[0007]

Means for Solving the Problems As means for solving the above-mentioned problems, the invention according to claim 1 is characterized in that an input side shaft and an output side shaft are connected via a torsion bar while a steering shaft is connected. A rotor and a valve body of a rotary valve are provided on an input side shaft and an output side shaft, respectively, for controlling supply hydraulic pressure of a power cylinder, and the rotor is rotatably housed in the valve body. In a hydraulic power steering apparatus that is adapted to generate a supply hydraulic pressure according to the torsion bar torsion, one volume increases with the relative rotation of the rotor side member and the valve body side member, and the other volume increases. A pair of decreasing fluid chambers is provided, and the fluid chambers are connected to each other by a throttle passage. In the case of the present invention, when the rotor side member and the valve body side member rotate relative to each other with the torsion of the torsion bar, the volume of one fluid chamber increases and at the same time the volume of the other fluid chamber decreases. Fluid flows into one of the fluid chambers through the throttle passage. Then, when the fluid passes through the throttle passage, throttle resistance is generated, and this resistance attenuates the vibration generated between the rotor side member and the valve body side member.

According to a second aspect of the present invention, in the first aspect, a space filled with fluid is formed in one of the rotor side member and the valve body side member, and On the other of the valve body side members, a partition member for separating the inside of the space into two fluid chambers is protruded,
The gap between the partition member and the inner wall of the space was defined as a throttle passage. In the case of the present invention, when the rotor-side member and the valve body-side member relatively rotate with the torsion bar torsion, the partition member is rotationally displaced in the space, and the fluid in the fluid chamber on the side of reduced volume is partitioned. It flows into the fluid chamber on the side where the volume increases through the gap between the member and the inner wall of the space.
The vibration between the rotor side member and the valve body side member is attenuated by the throttle resistance when the fluid passes through the gap.

According to a third aspect of the present invention, while the input side shaft and the output side shaft are connected via a torsion bar, the rotor of the rotary valve and the valve body are controlled to control the hydraulic pressure supplied to the power cylinder for steering. The rotor is provided on the input side shaft and the output side shaft, respectively, and the rotor is rotatably accommodated in the valve body so as to generate a supply hydraulic pressure between the rotor and the valve body according to the torsion of the torsion bar. In the hydraulic power steering apparatus, a fluid chamber filled with a viscous fluid and a resistance member that rotates and displaces the fluid chamber when the torsion bar is torsionally deformed are provided. In the case of the present invention, when the torsion bar is twisted, the resistance member is rotationally displaced in the fluid chamber, and the viscous resistance at this time attenuates the vibration generated between the rotor side member and the valve body side member.

According to a fourth aspect of the present invention, in the third aspect, the inside of the cylindrical portion of the rotor into which the torsion bar is loosely inserted is a fluid chamber filled with a viscous fluid, and the end of the rotor near the output side shaft is provided. The resistance member protrudes from at least one of the inner peripheral surface near the portion and the outer peripheral surface of the torsion bar facing the inner peripheral surface. In the case of the present invention, when the torsion bar is twisted, a relative rotation occurs between the inner peripheral surface near the end near the output shaft of the rotor and the outer peripheral surface of the torsion bar opposed thereto. The resistance member is displaced in the fluid chamber and receives a viscous resistance. Vibration between the rotor side member and the valve body side member is damped by this viscous resistance.

According to a fifth aspect of the present invention, in the fourth aspect of the invention, the inside of the cylindrical portion of the rotor is used as a hydraulic fluid flow path of the rotary valve. In the case of the present invention, the hydraulic fluid in the rotary valve flows into the peripheral region of the resistance member, and the hydraulic fluid functions as a viscous fluid that imparts resistance to the resistance member.

[0012]

Next, an embodiment of the present invention will be described with reference to the drawings.

First, the first embodiment of the present invention shown in FIGS.
(Embodiment corresponding to the first and second aspects of the present invention) will be described.

FIG. 2 is a longitudinal sectional view showing a main part of a hydraulic power steering apparatus according to the present invention. In FIG. 2, reference numeral 1 denotes a stub shaft as an input side shaft, and 2 denotes an output side shaft. As the pinion shaft. The stub shaft 1 is integrally connected to a steering shaft (not shown), and the pinion shaft 2 is engaged with a rack 3 penetrating a steering power cylinder (not shown).

Stub shaft 1 and pinion shaft 2
Are rotatably supported in the valve housing 6 via bearings 4 and 5, respectively, and are connected to each other via a torsion bar 7. One end of the torsion bar 7 (FIG. 2)
The lower end (in the middle) is serrated and connected to the pinion shaft 2, and the other end (the upper end in FIG. 2) is fixed to the base wall of the stub shaft 1 by pins 8 while being loosely inserted into the cylindrical portion of the stub shaft 1. . Further, the distal end (lower end in FIG. 2) of the stub shaft 1 is provided with a metal bearing 11 in a concave portion 10 provided at the base end (upper end in FIG. 2) of the pinion shaft 2.
And is rotatably supported via the. Therefore, when a torque equal to or more than a predetermined value acts between the stub shaft 1 and the pinion shaft 2, a torsion bar 7 is twisted in accordance with the torque, and as a result, the stub shaft 1 and the pinion shaft 2 relatively rotate.

A cylindrical valve body 12 is integrally connected to an outer periphery of a base end portion of the pinion shaft 2 by a pin (not shown), and the valve body 12 is connected to an outer periphery of the stub shaft 1 in the valve housing 6. Side is rotatably fitted. In this embodiment, a portion of the stub shaft 1 where the valve body 12 is fitted constitutes a rotor 13 according to the present invention, and the rotor and the 13 valve body 12 serve to supply hydraulic pressure of the steering power cylinder. , A rotary valve 14 is configured.

The rotor 13 (valve body 12) has a supply passage a connected to the hydraulic pump P and cylinder passages b and c respectively connected to the right cylinder chamber C1 and the left cylinder chamber C2 of the steering power cylinder. The stub shaft 1 has a return passage d connected to the reservoir tank T.
Are formed. The structure of these passages a, b, c, d of the rotor 13 and the stub shaft 1 is the same as that of a well-known rotary valve.
When the rotor 13 and the valve body 12 rotate relative to each other due to the torsion of the torsion bar 7, these passages a, b, c,
d is appropriately switched in accordance with the relative rotation, or the aperture amount is adjusted. In addition, the return passage d
Is formed utilizing the inside of the cylindrical portion of the rotor 13 into which the torsion bar 7 is loosely inserted.

As shown in FIGS. 1 to 3, a reduced diameter portion 15 is formed in the vicinity of the tip end of the rotor 13 in a step shape, and the reduced diameter portion 1 is provided at the base end of the pinion shaft 2.
5, two substantially closed space portions 16 and 1 facing the outer peripheral surface of
6 are formed. Each space 16 is provided with a rotor 13
And an arc-shaped inner wall 16a concentric with the inner wall 16a. Then, on the outer periphery of the reduced diameter portion 15 of the rotor 13, each of the space portions 16,
A pair of blades 18 as partition members extending into
18 are provided, and each of the blades 18
The interior is divided into two fluid chambers 19A and 19B. However, the rotary valve 1 is provided in each space 16.
4 is filled with the hydraulic fluid, and a gap 20 functioning as a throttle passage is provided between the tip of each blade 18 and the arc-shaped inner wall 16a of the space 16. Therefore, when each blade 18 rotates in the corresponding space 16, the volume of one fluid chamber 19 </ b> A in each space 16 increases and the volume of the other fluid chamber 19 </ b> B decreases. The hydraulic fluid in the fluid chamber 19B on the decreasing side passes through the gap between the blade 18 and the inner wall of the space 16 and the fluid chamber 19A on the increasing side in volume.
Flows into.

The arc-shaped inner wall 16a of each space 16
Are formed with two protruding ridges 21 and 21 extending in the axial direction in the circumferential direction, and the tip surface of each blade 18 of the rotor 13 is formed in the same axial direction as the pinion shaft 2 side. One ridge 22 is formed. The ridge 22 of each blade 18 is set so as to be located between two adjacent ridges 21 and 21 on the pinion shaft 2 side in an initial state in which the torsion bar 7 is not torsionally deformed. When the rotor 13 and the pinion shaft 2 rotate relative to each other due to the torsion, the ridge 22 on the blade 18 side approaches the one ridge 21 on the pinion shaft 2 side as shown in FIGS. Is gradually narrowed.

Since the hydraulic power steering apparatus has the above-described configuration, when the torsion bar 7 is twisted and deformed during the steering operation, the rotor 13 and the valve body 12 constituting the rotary valve 14 are accordingly caused.
Are relatively rotated, and the hydraulic pressure is controlled by the relative rotation to supply the power to the steering power cylinder.

When the rotor 13 and the valve body 12 rotate relative to each other at this time, the blades 18 on the rotor 13 side move as shown in FIGS.
The hydraulic fluid in the fluid chamber 19B on the side where the volume is reduced flows through the gap 20 into the fluid chamber 19A on the side where the volume is increased, and a throttle resistance is generated at this time. I do. Therefore, the vibration between the rotor side member and the valve body side member due to the torsion of the torsion bar 7 is reliably attenuated by the throttle resistance.

Further, in the case of this power steering device, when the torsion of the torsion bar 7 increases, the ridge 22 on the blade 18 side approaches the one ridge 21 on the pinion shaft 2 side to gradually narrow the gap 20. The generated throttle resistance increases in accordance with the torsion of the torsion bar 7, and the vibration generated between the rotor side member and the valve body side member is more effectively attenuated.

In the power steering apparatus according to the present invention, the gap 2 is changed according to the change in the volume of the fluid chambers 19A and 19B.
Since the vibration is attenuated by the throttle resistance of the working fluid flowing through the zero, high damping performance can be maintained over a long period of time as compared with the case where a rubber material or the like is used. In the case of this power steering device, a space 16 is formed in the pinion shaft 2, while a blade 18 serving as a partition member is protrudingly provided on the outer periphery of the rotor 13, and a tip of the blade 18 and an inner wall of the space 16 are formed. Since the gap 20 formed between the apertures 16a is used as a throttle passage, the passage structure is simple and can be manufactured at low cost, and the apparatus can be made more compact than when a special throttle passage is separately provided. It is also possible to aim.

Next, a second embodiment of the present invention shown in FIGS. 5 and 6 will be described.

The power steering apparatus according to this embodiment is characterized in that a stub shaft 1 and a pinion shaft 2 are connected by a torsion bar 7 and a rack 3 penetrating through a power cylinder for steering is engaged with the pinion shaft 2. 1 is formed in a cylindrical shape and the torsion bar 7 is loosely inserted into the cylindrical portion of the stub shaft 1, while the cylindrical valve body 12 is coupled to the base end of the pinion shaft 2, while the stub shaft The basic structure of the first embodiment is that the rotor 13 at the front end of the first rotor 13 is rotatably housed in the valve body 12, and the rotor 13 and the valve body 12 constitute a rotary valve 14. It is the same as that of the form.
The same parts as those in the first embodiment are denoted by the same reference numerals,
Further description of the overlapping part will be omitted.

This power steering differs from that of the first embodiment in the mechanism for attenuating the vibration between the rotor side member and the valve body side member. That is, in the case of this device, a pair of plate-shaped resistance members 30 projecting radially outward is provided near the end of the torsion bar 7 on the pinion shaft 2 side.
When the torsion occurs, the resistance member 30 rotates within the cylindrical portion of the rotor 13. And
Since the inside of the cylindrical portion of the rotor 13 is a working fluid passage of the rotary valve 14, the surrounding area of the resistance member 30 is always filled with the working fluid which is a viscous fluid. That is, the rotor 1
The inside of the cylindrical portion 3 is a fluid chamber filled with a viscous fluid.

Since the power steering apparatus is configured as described above, when the torsion bar 7 is twisted by the operation of the steering, the resistance member 30 is moved to the rotor 1.
3 in the cylindrical portion, and at this time, the resistance member 30
Receives viscous resistance from the hydraulic fluid, and the viscous resistance attenuates vibration between the rotor side member and the valve body side member. Also in the case of this embodiment, since the vibration is attenuated by the viscous resistance of the liquid, there is no decrease in the damping performance with use over time.

In this power steering device, a mechanism for damping vibration is provided in the cylindrical portion of the rotor 13 which has conventionally been a dead space. Therefore, a special occupied space is required for disposing the vibration damping mechanism. Need not be secured, and the apparatus can be downsized accordingly. Further, in the case of this device, since the inside of the cylindrical portion of the rotor 13 is used as a working fluid passage of the rotary valve 14 and the working fluid is introduced into the surrounding region of the resistance member 30, the viscous fluid is separately provided in the surrounding region of the resistance member 30. No need to fill
There is also an advantage that manufacturing becomes easier and cost can be reduced.

In the case of the second embodiment described above,
The resistance member 30 is protruded from the torsion bar 7.
As in the third embodiment shown in FIG. 8, a similar resistance member 30 may be protruded from the inner peripheral surface near the end of the rotor 13 on the pinion shaft 2 side. 7 and 8, the same parts as those of the second embodiment shown in FIGS. 5 and 6 are denoted by the same reference numerals.

[0030]

As described above, the invention according to claim 1 is
A pair of fluid chambers is provided in which one volume increases and the other volume decreases with the relative rotation of the rotor-side member and the valve body-side member, and the fluid chambers are communicated with each other by a throttle passage. Vibration between the rotor side member and the valve body side member can be reliably attenuated by the throttle resistance. Therefore, according to the present invention, the vibration generated between the rotor-side member and the valve body-side member can be stably attenuated for a long period of time without deteriorating the performance due to use over time.

According to a second aspect of the present invention, in the first aspect, a space filled with a fluid is formed in one of the rotor side member and the valve body side member. On the other of the valve body side members, a partition member for separating the inside of the space into two fluid chambers is protruded,
Since the gap between the partition member and the inner wall of the space is defined as a throttle passage, there is no need to separately provide a special pipe for forming the throttle passage, so that the manufacturing becomes easier and the manufacturing cost can be reduced. , And the device can be made more compact.

According to the third aspect of the present invention, since the fluid chamber filled with the viscous fluid and the resistance member which rotates and displaces the fluid chamber when the torsion bar is torsionally deformed are provided, the viscous force acting on the resistance member is provided. The vibration between the rotor side member and the valve body side member can be reliably attenuated by the resistance. Therefore, also in the present invention, the vibration between the rotor-side member and the valve body-side member can be stably attenuated for a long period of time without deteriorating the performance over time.

According to a fourth aspect of the present invention, in the third aspect, the inside of the cylindrical portion of the rotor into which the torsion bar is loosely inserted is a fluid chamber filled with a viscous fluid, and the end of the rotor near the output side shaft is provided. The resistance member protrudes from at least one of the inner peripheral surface in the vicinity of the rotor and the outer peripheral surface of the torsion bar opposed to the inner peripheral surface. Viscous drag can be obtained. Therefore, according to the present invention, it is not necessary to secure a special occupied space for adding the vibration damping function, and as a result, it is possible to further reduce the size of the device.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the inside of the cylindrical portion of the rotor is used as a hydraulic fluid flow path of the rotary valve, and the hydraulic fluid of the rotary valve gives viscous resistance to the resistance member. Since it functions as a fluid, it is not necessary to fill the fluid chamber in the rotor with a special viscous fluid, and as a result, production at lower cost is possible.

[Brief description of the drawings]

1 shows a first embodiment of the present invention, AA of FIG. 2;
Sectional view along the line.

FIG. 2 is a cross-sectional view showing the embodiment.

FIG. 3 is a sectional view similar to FIG. 1 showing the embodiment;

FIG. 4 is an enlarged view of a main part of FIG. 3;

FIG. 5 is a sectional view showing a second embodiment of the present invention.

FIG. 6 is a sectional view taken along the line BB of the same embodiment.

FIG. 7 is a sectional view showing a third embodiment of the present invention.

FIG. 8 is a sectional view of the embodiment, taken along line CC in FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Stub shaft 2 ... Pinion shaft 7 ... Torsion bar 12 ... Valve body 13 ... Rotor 14 ... Rotary valve 16 ... Space 16a ... Inner wall 18 ... Blade (partition member) 19A, 19B ... Fluid chamber 20 ... Gap (throttle passage) 30 ... resistance member

Claims (5)

[Claims] An input side shaft and an output side shaft are connected via a torsion bar, and a rotor and a valve body of a rotary valve are respectively connected to an input side shaft and an output side to control a supply hydraulic pressure of a steering power cylinder. A hydraulic power steering device provided on the shaft and the rotor being rotatably housed in the valve body so as to generate a supply oil pressure between the rotor and the valve body in accordance with the torsion of the torsion bar. A pair of fluid chambers whose one volume increases and the other volume decreases with the relative rotation of the rotor side member and the valve body side member are provided, and the fluid chambers are communicated with each other by a throttle passage. Hydraulic power steering system. 2. A space to be filled with fluid is formed in one of the rotor side member and the valve body side member, and two spaces in the space are formed in the other of the rotor side member and the valve body side member. 2. The hydraulic power steering apparatus according to claim 1, wherein a partition member separating from the fluid chamber protrudes, and a gap between the partition member and an inner wall of the space is defined as a throttle passage. 3. An input side shaft and an output side shaft are connected via a torsion bar, and a rotor and a valve body of a rotary valve are respectively connected to an input side shaft and an output side to control a supply hydraulic pressure of a steering power cylinder. A hydraulic power steering device provided on the shaft and the rotor being rotatably housed in the valve body so as to generate a supply oil pressure between the rotor and the valve body in accordance with the torsion of the torsion bar. A hydraulic power steering apparatus, comprising: a fluid chamber filled with a viscous fluid; and a resistance member that rotates and displaces the fluid chamber when the torsion bar is torsionally deformed. 4. The inside of a cylindrical portion of a rotor into which a torsion bar is loosely inserted is defined as a fluid chamber filled with a viscous fluid, and an inner peripheral surface near an end near an output shaft of the rotor and an outer peripheral surface of the torsion bar opposed thereto. 4. The hydraulic power steering apparatus according to claim 3, wherein a resistance member is provided on at least one of the surfaces. 5. The hydraulic power steering apparatus according to claim 4, wherein the inside of the cylindrical portion of the rotor is used as a working fluid flow path of the rotary valve.