JP2515384Y2 - Power steering device - Google Patents

Description

The present invention relates to a power steering apparatus, and more particularly to a power steering apparatus in which an input shaft and an output shaft are connected to each other via a torsion bar.

[Conventional technology]

Conventionally, for example, as shown in JP-B-43-6022, an input shaft rotated by a steering handle,
The input shaft and an output shaft arranged on the same axis are connected by a torsion bar, and a rotary valve is constituted by a pair of valve members provided so as to rotate integrally with both shafts. BACKGROUND ART A power steering apparatus is generally known in which a rotary valve is switched according to relative rotational displacement of a shaft to control supply and discharge of pressure fluid to and from a power cylinder.

[Problems to be solved by the device]

By the way, in the above conventional power steering apparatus, since the reaction force mechanism is only the torsion bar, the micro rudder angle returns at high speed or the response of the micro rudder angle at high speed, and further the micro rudder at high speed There is a problem in that the maneuverability in the minute rudder angle range such as the steering force of the angle is poor and the number of corrections increases.

The present invention has been made in view of such a current situation. An object of the present invention is to provide a power steering device that can be reduced.

[Means for solving the problem]

The power steering apparatus according to the present invention includes an input shaft that is rotated by operating a steering handle, an output shaft that is disposed on the same axis as the input shaft, and an input / output shaft that are integrally rotatable. And a torsion bar arranged on the shaft portion of the input / output shaft to connect these shafts to each other, and a hole formed at either end of the input / output shaft. The end of the other shaft is fitted inside,
Further, at least one location on the outer peripheral surface of the input shaft is processed into a flat surface to form a flat surface, and a holder fixed to the output shaft and a flat surface of the input shaft held in the holder. A preset mechanism including a leaf spring to be pressed is provided, and the holder is configured to be rotatable relative to the output shaft when the preset mechanism is assembled.

[Action]

In the power steering apparatus according to the present invention, the flat spring formed in the outer peripheral surface of the input shaft is pressed against the flat spring held in the holder fixed to the output shaft, and is set by the biasing force of the flat spring. Force is given. Therefore, it is possible to improve the moderation feeling in the minute steering angle range, improve the steering wheel return, improve the steering force feeling when the steering wheel is turned off, and improve the straightness, and it is possible to reduce the number of steering wheel corrections. Moreover, when the holder is fixed to the output shaft, the holder can rotate relative to the output shaft, so that the centering is automatically performed.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows an example of an integral type power steering apparatus according to the present invention. A piston (6) is slidably fitted in a cylinder portion (4) of a gear housing (2). ,
The piston (6) divides the inside of the cylinder (4) into two pressure chambers (8) and (10). A rack (12) is provided on the side surface (the lower surface in FIG. 1) of the piston (6).
A sector gear (14) interlocking with a steering wheel (not shown) is meshed with the rack (12) so that the rack (12) rotates forward and backward as the piston (6) reciprocates.

A ball screw groove (18) is screwed into the hole (16) at the axial center of the piston (6), and a large number of balls (2) in the groove (18) are provided.
The worm shaft (22) is screwed through the (0). One end of the gear housing (2) has a valve housing (2
4) is fixed, and the input shaft (26) is arranged in the valve housing (24) with its axis aligned with the worm shaft (22). A cylindrical hole (22a) is formed on the input shaft (26) side of the worm shaft (22), and an end portion (26a) of the input shaft (26) is fitted in the hole (22a). Both axes (2
2) and (26) are connected by a torsion bar (28) inserted in the hole of each shaft core.

The fitting portion between the worm shaft (22) and the input shaft (26) allows the relative rotation of the shafts (22) and (26) by a predetermined amount, and at the same time, regulates the rotation so that the rotation is prevented. Safe is configured.

The input shaft (26) is linked to a steering wheel (not shown).

A rotary type control valve including a valve rotor (30) that rotates integrally with the input shaft (26) and a valve sleeve (32) formed on the worm shaft (22) in the valve housing (24). (34) is housed.

The control valve (34) communicates with an oil pump (not shown) through the supply passage and with a tank (not shown) through the return passage, and the control valve (34) is switched by operating the steering handle. And the pressure fluid discharged from the oil pump is the pressure chamber (8), (1
0) is supplied to one side and the other pressure chamber is communicated with the tank to generate a pressure difference between the two chambers, and the piston (6) is operated by this pressure difference to apply an assisting force in the steering direction. It has become.

The end of the valve sleeve (32) is rotatably supported by the valve housing (24) via a bearing (36) as shown in FIG. 1, and the base end of the input shaft (26). Are rotatably supported by the valve housing (24) via bearings (38). And these bearings (36),
As shown in FIGS. 1 and 2, a leaf spring (40) that gives a set force to the input shaft (26) is assembled between the (38).

That is, the bearings (36), (38) of the input shaft (26).
As shown in FIG. 3 and FIG. 4, the portion located between the two is flatly cut on both sides facing each other in the radial direction to form a flat surface (42).
A leaf spring (40) having a hat-shaped cross section is pressed against the outer surface of 2), and these leaf springs (40) are connected to each other via a bolt (44) as shown in FIGS. 2 to 4. It is housed in a holder (46) fixed to the end surface of the valve sleeve (32). A holder (46) fixed to the worm shaft (22) via a bolt (44) and a leaf spring (which is housed in the holder (46) and is pressed against the flat surface (42) of the input shaft (26). 40) constitutes the preset mechanism. A gap is provided between the bolt (44) and the bolt hole of the holder (46). Therefore, the holder (4
6) is a bolt (44) when the bolt (44) is fastened and fixed to the worm shaft (22), that is, the valve sleeve (32).
Is rotatable relative to the worm shaft (22) within the above-mentioned gap between the outer diameter of the bolt hole and the inner diameter of the bolt hole.

As shown in FIG. 3 and FIG. 4, the holder (46) is located on both sides of the penetrating portion (46a) through which the input shaft (26) penetrates and the dimension (L). Is formed by sintering or casting, and the flat surface (42) is formed on the upper and lower end portions of the respective storage portions (46b) on the side of the penetrating portion (46a). The holder abutting portions (48) are flush with each other.

On the other hand, as shown in FIG. 5, the leaf spring (40) is formed in a hat-shaped cross section from the arcuate portion (40a) and the abutting portions (40b) on both sides of the arcuate portion (40a). In the state of not being accommodated in the (46b), the dimension (L ') is set to be larger than the dimension (L) of the accommodating portion (46b). Then, the leaf spring (40) is elastically deformed to accommodate the storage portion (46
By being housed in b), the abutting portions (40b) are brought into pressure contact with the flat surface (42) and a set force is applied to the input shaft (26).

 Next, the operation of this embodiment will be described.

The leaf springs (40) housed in the housing parts (46b) of the holder (46) have the abutting parts (40b) of the input shaft (26) as shown in FIGS. 3 and 4. Flat surface of (42)
Pressed from the outside. Therefore, a set force is applied to the input shaft (26) at the neutral position of the control valve (34) by the urging force of the leaf springs (40).

Thus, it is possible to improve the feeling of moderation in the minute rudder angle range, the feeling of the steering force when the steering wheel is returned and when the steering wheel is turned off, the straightness can be improved, and the number of times the steering wheel is corrected can be reduced.

In the above embodiment, the flat surface (42) is formed at two locations on the outer peripheral surface of the input shaft (26), and a set force is applied to the input shaft (26) by using an even number of two or more leaf springs. Although the case has been described, the desired effect can be obtained if at least one leaf spring (40) is brought into pressure contact with one flat surface (42).

[Effect of device]

As described above, according to the present invention, at least one portion of the outer peripheral surface of the input shaft is processed into a flat surface to form a flat surface, and the flat spring supported by the output shaft is pressed against the flat surface. As a result, a set force can be obtained, a feeling of moderation in a small steering angle range can be improved, a steering wheel return can be improved, and a steering feeling feeling at the start of hand-reaching can be improved, and straightness can be improved. The number of times the handle is modified can be reduced.

Further, after assembling the control valve portion including the output shaft, the valve sleeve formed on the output shaft, the input shaft, the valve rotor connected to the input shaft by the pin and rotating integrally, and the torsion bar, the preset mechanism Although the holder is fixed to the output shaft via the bolt, in the present invention,
For example, the holder can be rotated relative to the output shaft by, for example, providing a gap between the bolt and the bolt hole, so that the leaf spring held in the holder of the preset mechanism balances the holder. By automatically aligning to the position and then tightening and fixing the bolts,
The preset force of the preset mechanism can be balanced.

[Brief description of drawings]

FIG. 1 is a sectional view of a power steering apparatus showing an embodiment of the present invention, FIG. 2 is an enlarged view of a main part thereof, and FIG. 3 is a III-III line of FIG. 2 showing a structure of a leaf spring and a holder. Cross-sectional equivalent view, 4th
The figure is a view equivalent to the IV-IV line cross section of the same FIG. 2, and FIG. 5 is a configuration diagram showing a state before being attached to the holder of the leaf spring. (22) …… Worm shaft (output shaft), (22a) …… Hole, (2
6) …… Input shaft, (28) …… Torsion bar, (30)…
… Valve rotor, (32) …… valve sleeve, (34) …… control valve (rotary valve), (40) …… leaf spring,
(40a) …… Arc part, (40b) …… Abutting part, (42) …… Flat surface, (44) …… Bolt, (46) …… Holder, (46a)
...... Penetration part, (46b) …… Storage part, (48) …… Holder abutment part.

Claims (1)

(57) [Scope of utility model registration request] 1. An input shaft that is rotated by operating a steering handle, an output shaft that is arranged on the same axis as the input shaft, and an input / output shaft that are integrally rotatably mounted on a rotary valve. And a torsion bar arranged on the shaft portion of the input / output shaft to connect these shafts,
In a power steering apparatus in which an end portion of the other shaft is fitted in a hole formed in one end portion of the input / output shaft, at least one place is flattened on an outer peripheral surface of the input shaft. A preset mechanism is provided that includes a holder that is machined to form a flat surface and that is fixed to the output shaft, and a leaf spring that is held in the holder and is pressed against the flat surface of the input shaft. A power steering apparatus, wherein the holder is configured to be rotatable relative to an output shaft when a mechanism is assembled.