JPS62155169A - Power steering device - Google Patents

Abstract

PURPOSE:To enable a power steering device to be reasonably arranged even with no sufficient space in the connecting direction of a steering handle, by arranging a servo valve in an opposite side to the input end part for a rack shaft so that a distance between the input end part and the rack shaft is decreased. CONSTITUTION:A servo valve 40 is housed in a valve housing of a power steering device A. And a pinion 32a is provided in an output shaft, meshing with a rack shaft 50 connected with steering link mechanisms 16 of wheels 15. While the servo valve 40, which controls working fluid to be supplied to an discharged from a power cylinder 47 giving assist force to the rack shaft 50, is provided between the other end part of an input shaft and the output shaft. And the power steering device A, which transmits turning of a steering handle 10 to an input end part 30a of the input shaft actuating the servo valve 40 on the basis of relative turning between the input and output shafts, gives the assist force to the rack shaft 50 by controlling the working fluid to be supplied to and discharged from the power cylinder 47.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a power steering device for a vehicle.

[Prior art]

In a power steering device in which a rank shaft connected to a wheel steering link mechanism is meshed with a binion formed on an output shaft, a steering wheel is connected to a steering wheel, as shown in Japanese Patent Application Laid-open No. 60-139571, for example. A servo valve that controls supply and discharge of working fluid to and from the power cylinder is provided at an intermediate position between the input end of the connected input shaft and the rack shaft. Such a power steering device is attached to the frame so that the rack shaft is in a predetermined positional relationship with respect to the steering link mechanism.

[Problem that the invention seeks to solve]

In this type of power steering system, depending on the configuration of the vehicle body, there may not be enough space in the connection direction of the steering handle relative to the position of the rack shaft, and in such cases, the input end of the input shaft It becomes necessary to shorten the distance between the rack shaft and the rack shaft. However, in the conventional power steering device, there is a problem in that the distance cannot be shortened because the servo valve is located between the input end and the rank shaft as described above. The present invention solves these problems by improving the structure of the power steering device.

[Means for solving problems]

For this purpose, the power steering device according to the present invention includes an input shaft 30 and an output shaft 32, which are rotatably supported by a housing 20 and elastically connected to each other so as to be relatively rotatable, as illustrated in the accompanying drawings. A rank shaft 50 meshes with a pinion 32a provided on the output shaft and is connected to the steering link mechanism 16 of the wheels 15; a first valve member 41 and a second valve member connected to the input shaft 30 and the output shaft 32, respectively; A power source comprising a servo valve 40 that controls supply and discharge of working fluid to a power cylinder 47 which is made up of a valve member 42 and is operated based on the relative rotation of both shafts 30 and 32 to provide an assist force to the rack shaft 50. In the steering device, the input shaft 30 coaxially penetrates the inside of the output shaft 32, has both ends protruding from the output shaft in opposite directions, and is connected to one end of the input shaft 30 to the steering handle 10. input end 30
a, and the other end of the input shaft 30 and the output shaft 3
This is characterized in that the servo valve 40 is provided between the two.

[Effect]

The rotation of the steering handle 10 is transmitted to the input end 30a at one end of the human power shaft 30, and at the same time as the output shaft 32 is rotated, there is a connection between the two shafts 30, 32 corresponding to the manual torque applied to the steering handle 10. Relative rotation occurs. Output shaft 3
A servo valve 40 provided between the other end of the input shaft 30 and the output shaft 32 passing through the power cylinder 40 operates based on the relative rotation, controls the supply and discharge of working fluid to the power cylinder 40, and controls the rack shaft. Gives assist power to 50.

〔Effect of the invention〕

Since the power steering device according to the present invention is configured as described above, the servo valve is arranged on the opposite side of the input end with respect to the rank shaft, thereby making it possible to shorten the distance between the input end and the rank shaft. . Therefore, if the power steering device of the present invention is used, even if the vehicle body structure does not have enough space in the connection direction of the steering handle relative to the position of the rank axis determined by the steering link mechanism, the power steering device can be used easily. can be placed.

〔Example〕

1 and 2 show a power steering device A according to the present invention,
This is an example in which the present invention is used in a rear wheel side steering device of a four-wheel steering device.

In FIG. 2, the power steering device B for the front wheels has a normal configuration, and the rotation of the steering handle 10 is controlled by the handle shaft 11.
is transmitted to the input shaft 13a via the shaft joint and intermediate shaft,
Rack shaft B to which assist force is applied by power cylinder
This is converted into a movement of b, causing a steering rotation to occur in the front wheels 13.13 via the steering linkage mechanism 14.14. The power steering device A for the rear wheels is according to the present invention, and includes a steering handle 1.
The rotation of 0 is transmitted from the handle shaft 11 to the drive pinion 56 via the shaft coupling, intermediate shaft, gear, transmission position (not shown) where the gear ratio changes depending on the operating condition, and the drive shaft 12.
The assist force is applied by the power cylinder 47 and is converted into movement of the rack shaft 50, causing steering rotation of the rear wheels 15, 15 via the steering link mechanism 16.

Next, a description will be given of a power steering device embodying the present invention.

As shown in FIG.
2, an output shaft 32 having an inner hole 32b is rotatably supported in the center of the housing 20 via bearings 25 and 26, and an input shaft 30 is coaxially supported in the inner hole 32b of the output shaft 32. It penetrates through the housing 20, and both ends thereof are rotatably supported by the housing 20 via bearings 23 and 24. One end of the input shaft 30 protrudes to the right from the output shaft 32 to form an input end 30a.
An input pinion 31 is integrally formed on this input end portion 30a.

A torsion bar 33 is provided in an inner hole 30c formed coaxially with the input shaft 30, and one end of the torsion bar 33 passes through an opening 30b provided in the diametrical direction of the input shaft 30 with a sufficiently large gap therebetween. It is coupled to one end of the output shaft 32 by a coupling pin 34 . The other end of the input shaft 30 protrudes to the left from the output shaft 32, and its tip is connected to the other end of the torsion bar 33 by a connecting pin 35, so that both shafts 3
0.degree. 32 is elastically connected via a torsion bar 33 so as to be relatively rotatable within the range allowed by the gap between the opening 30b and the coupling pin 34.

An output pinion 32a integrally formed with the output shaft 32 meshes with a rack 50a of an output rack shaft 50 supported by the gear housing 21 so as to be slidable in a direction perpendicular to the output pinion 32a.

As shown in FIG. 2, both ends of the output rack shaft 50 are connected to a steering link mechanism 16 consisting of a knuckle arm 16a and a tie rod 16b, which are pivotally supported to the frame by a king pin 16c.
The output rack shaft 50 is connected to the left and right rear wheels 15, 15 via a power cylinder 47 which provides an assisting force.

An input pinion 31 integrally formed on an input end 30a of the input shaft 30 meshes with a rack 55a of an input rack shaft 55 supported by the gear housing 21 so as to be slidable in parallel with the output rack shaft 50. The rack 55a also meshes with the aforementioned drive pinion 56, as shown in FIG.

As shown in FIG. 1, the other end of the input shaft 30 and the output shaft 3
A servo valve 40 housed within the valve housing 22 is provided between the valve housings 20 and 20 . The servo valve 40 has a rotor valve member (first valve member) 41 that is integral with the other end of the input shaft 30, and is fitted on the outer periphery of the rotor valve member (first valve member) so as to be relatively rotatable coaxially, and is connected to the output shaft 32 via a connecting pin 43 at one end. The main component is a sleeve valve member (second valve member) 42 connected to the other end, and a plurality of lands and grooves extending in the axial direction are alternately formed on the fitting surfaces of both valve members 41 and 42. is formed. Working fluid from a supply pump (not shown) supplied through the supply path 44 is transferred to the distribution path 4 when the servo valve 40 is in the neutral state.
5.45, the same low pressure is applied to both the left and right sides of the power cylinder 47, and the air is discharged from the discharge passage 46. Input shaft 30
When the output shaft 32 rotates relative to the servo valve 40 and the servo valve 40 rotates and deviates from the neutral state, the working fluid from the supply pump applies a differential pressure corresponding to the amount of deviation of the servo valve 40 to the power cylinder 470. It applies assist force to both chambers and to the output rack shaft 50.

In a straight-ahead state where no manual torque is applied to the steering wheel 10, the servo valve 40 is in a neutral state, and the power cylinder 47 does not apply assist force to the output rack shaft 50.

When manual torque is applied to the steering wheel 10 to rotate it from the straight-ahead state, this rotation is transmitted to the drive pinion 56 of the power steering device A, and further via the input rank shaft 55 and the input pinion 31 to the input shaft 30. The signal is transmitted to the end portion 30a and rotates the input shaft 30. The torsion bar 33 transmits the rotation of the input shaft 30 to the output shaft 32, and at the same time generates a tear corresponding to the manual torque of the steering handle 10, causing relative rotation between the two shafts 30, 32. Due to this relative rotation, the rotor valve member 41 and the sleeve valve member 42 provided on the other end side of the input shaft 30 passing through the output shaft 32
The servo valve 40 is rotationally deviated from the neutral state by relative rotation, and the power cylinder 47 applies an assist force to the output rank shaft 50 according to the amount of this deviation.

In the above embodiment, the rotation of the drive shaft 12 is transmitted to the input end 30a of the input shaft 30 via the drive pinion 57, the input rank shaft 55, and the input pinion 31. 30a to transmit rotation of the steering handle 10. Further, the power steering device of the present invention is not limited to a rear wheel steering device of a four-wheel steering device, but can also be used for a front wheel steering device or a normal front wheel steering device.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a power steering device according to the present invention;
FIG. 2 is an overall view when the power steering device of the present invention is used as the rear wheel side steering device of a four-wheel steering system. Explanation of symbols 10... Steering handle, 15... City axis (rear wheel),
16... Steering link mechanism, 20... Housing, 3
0...Input shaft, 30a...Input end, 32a...
・Pinion (output pinion), 40... Servo valve, 4
1...First valve member (rotor valve member), 42...Second
Valve member (sleeve valve member), 47... power cylinder,
50... Rack axis (output rank axis), A... Power steering device.

Claims (1)

[Claims] An input shaft and an output shaft rotatably supported by the housing and elastically connected to each other so as to be rotatable relative to each other, and a rack that meshes with a pinion provided on the output shaft and is connected to a wheel steering link mechanism. actuation to a power cylinder that is made up of a shaft, a first valve member and a second valve member connected to the input shaft and the output shaft, respectively, and is operated based on the relative rotation of the two shafts to apply an assist force to the rack shaft; In a power steering device comprising a servo valve for controlling supply and discharge of fluid, the input shaft coaxially penetrates the inside of the output shaft and has both ends protruding from the output shaft in opposite directions, and A power steering device characterized in that an input end connected to a steering handle is provided at one end of an input shaft, and the servo valve is provided between the other end of the input shaft and the output shaft.