JP2509939Y2 - Power steering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a power steering apparatus, and more particularly to a power steering apparatus having a reaction force mechanism.

[Conventional technology]

FIG. 8 is a vertical cross-sectional view of a conventional integral type power steering apparatus, and FIG. 9 is a cross-sectional view of a reaction force mechanism portion. A piston is provided in a cylinder portion (4) in a gear housing (2). (6) is slidably fitted, and the inside of the cylinder (4) is divided into two pressure chambers (8) and (10) by this piston (6). A rack (12) is formed on a side surface (a lower surface in FIG. 8) of the piston (6), and a sector gear (14) interlocking with a steering wheel (not shown) is meshed with the rack (12) to form a piston ( With the reciprocating movement of 6), it is designed to rotate forward and backward.

A ball screw groove (18) is screwed into the hole (16) at the axial center of the piston (6), and a number of balls (1) in the groove (18) are screwed.
The worm shaft (output shaft) (20) is screwed through 9). A cylindrical portion (22a) of the valve housing (22) is fitted to one end of the gear housing (2), and a bolt (24)
Has been fixed by. This valve housing (22)
A stub shaft (input shaft) (26) is disposed inside the worm shaft so that the worm shaft (20) is aligned with the worm shaft (20). Worm axis (2
0) has a large-diameter cylindrical portion (20a) formed at the end on the stub shaft (26) side, and the tip portion of the stub shaft (26) is inserted into the cylindrical portion (20a) via a bearing (28). Are fitted together. The two shafts (20) and (26) are connected by a torsion bar (30) inserted in a hole at the center of the shafts. In addition, the inner surface of the worm shaft (20) and the outer surface of the stub shaft (26) allow a predetermined amount of relative rotation of both shafts (20) and (26), and limit the further rotation. Safe (32) is formed. The stub shaft (26) is connected to a steering handle (not shown) and rotated.

A valve rotor (inner valve member) (34) is formed directly on the outer peripheral surface of the central portion of the stub shaft (26), and a valve sleeve (outer valve member) (36) is fitted around the outer periphery thereof. The valve sleeve (36) is connected to a worm shaft (20) via a pin (38) so as to rotate integrally therewith. The valve rotor (34) and the valve sleeve (36) enable a rotary type. A control valve (40) is configured.

The control valve (40) is fitted with a valve housing (2
It communicates with the oil pump through the supply port (42) formed in 2) and the tank through the return port (44), and the control valve (40) is switched by operating the steering handle. Then, the pressure oil discharged from the oil pump is supplied to one of the pressure chambers (8) and (10), and the other pressure chamber is communicated with the tank to generate a pressure difference between the two chambers. The piston (6) is operated by the pressure difference to apply an assisting force in the steering direction.

The stub shaft (2) of the large-diameter cylindrical part (20a) of the worm shaft (20)
6) The side end is fitted to the outer periphery of the valve sleeve (36) and a ball bearing (2) that rotatably supports both the worm shaft (20) and the stub shaft (26) with respect to the valve housing (22). 46) constitutes the inner race (46a). The outer race (46b) of the ball bearing (46) is inserted between the outer peripheral surface of the cylindrical portion (20a) of the worm shaft (20) and the cylindrical portion (22a) of the valve housing (22) and has a screw portion (48). It is held at the bottom of the valve housing (22) by an adjusting plug (50) fixed by the.

A reaction force mechanism (51) is provided near the cylinder in the portion where the worm shaft (20) and the stub shaft (26) are fitted. The reaction force mechanism (51) will be described. A plurality of (three in this embodiment) circular holes (52) radially extending through the large-diameter cylindrical portion (20a) of the worm shaft (20) at equal intervals in the circumferential direction.
Are formed. A reaction force plunger (54) is slidably fitted in each of the circular holes (52). An arcuate recess is formed on the inner end surface of the reaction force plunger (54), and the ball (56) is held in the recess.
On the other hand, on the outer circumference of the stub shaft (26), the large annular portion (26
a) is provided, and in this large diameter portion (26a) there are three V-shaped grooves (5
7) has been formed. Then, due to the hydraulic pressure introduced into the outer space (hydraulic reaction chamber) of the reaction force plunger (54) in the circular hole (52), the ball (56) is moved through the reaction force plunger (54) to move the stub shaft (26). The V-groove (57) is pressed to generate a steering reaction force.

[Problems to be solved by the device]

In the power steering apparatus including the reaction force mechanism having the above configuration, it is difficult to match the center of the hydraulic pressure with the neutral position of the reaction force mechanism due to a machining error of the valve groove provided in the control valve.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and it is possible to perform centering (centering) between the hydraulic center of the control valve and the neutral position of the reaction mechanism, and yet to maintain the centered state. The present invention provides a power steering apparatus including a reaction force mechanism capable of performing the above.

[Means for solving the problem]

The power steering apparatus according to the present invention includes a radial hole formed in one of the input / output shafts, a reaction force plunger slidably fitted in the hole, and an inner end surface of the reaction force plunger. An antiball composed of a ball held in a recess provided eccentrically from the center of its outer diameter and an axial groove formed on the outer surface of the other shaft and pressed by the hydraulic pressure acting on the reaction force plunger. In a power steering apparatus including a force mechanism, a spring member fixed to the inner peripheral surface of the radial hole by being pressed against the inner peripheral surface of the radial hole is attached to the outer peripheral side opening of the radial hole, and the reaction force The outer end of the plunger is provided with a whirl-stop portion that engages with the engaging portion of the spring member and restricts rotation of the reaction force plunger.

[Action]

In the power steering apparatus according to the present invention, the reaction force plunger is rotated to match the neutral position of the reaction force mechanism with the center of the hydraulic pressure, and then the spring member is mounted in the radial hole to remove the reaction force plunger. The rotation is regulated to maintain the aligned state, and the spring force prevents the reaction force plunger from coming out of the radial hole.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of an essential part showing a reaction force mechanism in a power steering apparatus according to an embodiment of the present invention, and FIG. 2 is a plan view thereof. The reaction force mechanism (151) according to the present embodiment includes the worm shaft (2
0) is provided with a plurality (for example, three) of radial circular holes (152) formed at equal intervals in the circumferential direction.
A reaction force plunger (154) is slidably fitted in the inside of 2).

Inner side end surface of reaction force plunger (154) (downward in FIG. 1)
A recess (154a) is formed in the recess (154a).
a) consists of an arc of a diameter larger than the diameter of the ball (156) held therein. Moreover, as shown in FIG. 3, the recess (154a) is provided at a position where its center (o ₁ ) is displaced from the axis (o ₂ ) of the reaction force plunger (154) in the radial direction by (Δδ). ing. The ball (156) is fitted in an axial V-shaped groove (157) formed on the outer surface of the stub shaft (26).

As shown in FIGS. 1 and 2, a cylindrical protrusion (158) is formed at the center of the outer end surface of the reaction force plunger (154).
Is integrally provided, and as shown in FIG. 3, an operation groove (for operating the rotation of the reaction force plunger (154) by inserting the tip of a tool (160) such as a driver into the outer end surface of the operation groove (154). 162) is provided.

On the other hand, a coil spring (164) fixed in pressure contact with the inner peripheral surface of the circular hole (152) by its own expansion force is provided at the outer opening (upper side in FIG. 1) of the circular hole (152). The engaging portion (166) of the coil spring (164) that is mounted is engaged with the operation groove (162) and restricts rotation of the reaction force plunger (154). That is, the operation groove (162) also serves as a rotation stopping portion that restricts rotation of the reaction force plunger (154).

 Next, the operation of this embodiment will be described.

When assembling the reaction force mechanism (151), at the neutral position of the control valve, the reaction force mechanism (15
1) If neutrality cannot be obtained, insert the tip of the tool (160) into the operation groove (162) of the reaction force plunger (154),
Rotate the reaction force plunger (154) while pushing it toward the ball (156) side. Then, the reaction force plunger (154) rotates with respect to the ball (156) in the V-shaped groove (157), and the centering (the neutral position of the reaction force mechanism (151) is centered on the hydraulic pressure at the position where the reaction force plunger (154) is in the lowest position. Will be matched).

In this state, the coil spring (164) is attached to the outer peripheral side opening of the circular hole (152), and the engaging portion (166) of the coil spring (164)
As shown in FIGS. 2 and 2, the operation groove (162) is fitted and locked. Since the outer peripheral surface of the coil spring (164) is pressed against the inner peripheral surface of the circular hole (152) by its own expansion force, it is fixed in the axial direction of the circular hole (152) and around the shaft at the mounting position. As a result, the rotation of the reaction force plunger (154) is restricted, the reaction force plunger (154) is held in the aligned state, and the reaction force plunger comes out of the circular hole (152) and hits the housing side. Is also blocked.

The coil spring (164) and the reaction force plunger (1
As shown in Fig. 1, a predetermined gap is provided between the outer end face of the reaction force plunger (154) and the circular hole (15) of the reaction force plunger (154).
It goes without saying that it is necessary to prevent sliding within 2).

4 to 6 show another embodiment of the present invention, in which the projection (158) and the operating groove (1) in the above embodiment are used.
The projection (258) and the operation groove (262) are provided in place of 62), and a C ring-shaped snap ring (264) is used in place of the coil spring (164).

That is, as shown in FIGS. 4 and 5, a projection (258), one end of which extends to the outer periphery of the reaction force plunger (154), is integrally provided on the outer end surface of the reaction force plunger (154). And the operation groove (26
2) is provided.

On the other hand, at the outer peripheral side opening of the circular hole (152) (upward in FIG. 4), a C-ring snap ring (which is fixed by pressure contact with the inner peripheral surface of the circular hole (152) by its own expansion force ( 26
4) is attached, and by holding the ends of the protrusion (258) from both sides at both ends, the reaction force plunger (15
The rotation of 4) is regulated. That is,
In this embodiment, both ends of the snap ring (264) have a function of the engaging portion (166) in the above embodiment, and the protrusion (258) has a function of a rotation stopping portion that engages with the engaging portion (166). are doing.

In other respects, the configuration is the same as that of the above-mentioned embodiment and the operation is the same, but the reaction force mechanism (151)
When assembling the tool, as shown in Fig. 6, the tool (160)
It is preferable to provide the guide portion (160a) of the snap ring (264) in order to improve workability.

Further, in the present embodiment, the case where the snap ring (264) is directly brought into pressure contact with the inner peripheral surface of the circular hole (152) has been shown. However, as shown in FIG. Ring groove (2
52) may be provided and the snap ring (264) may be mounted in the ring groove (252). Further, the snap ring (264) may have not only a rectangular cross section but also a round cross section, and its outer shape is not limited to the C shape and may be a curved shape or the like.

Even if the snap ring (264) is used, the same effect as that of the above embodiment can be expected.

[Effect of device]

As described above, according to the present invention, it is possible to prevent the reaction force mechanism from slipping out after the neutral position of the reaction force mechanism and the hydraulic center of the control valve are aligned with each other, and it is possible to prevent the reaction force plunger from slipping out.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing a reaction force mechanism in a power steering apparatus according to an embodiment of the present invention, and FIG. 2 is a plan view of FIG.
FIG. 3 is an explanatory view showing an alignment method in this reaction force mechanism,
FIG. 4 is a view corresponding to FIG. 1 showing another embodiment of the present invention, and FIG.
4 is a plan view of FIG. 4, FIG. 6 is an explanatory view showing an aligning method in this reaction force mechanism, FIG. 7 is an explanatory view showing a modified example of a snap ring mounting portion, and FIG. 8 is a conventional integral. FIG. 9 is a vertical cross-sectional view of the mold power steering apparatus, and FIG. 9 is a cross-sectional view of the reaction force mechanism portion thereof. (151) …… Reaction mechanism, (152) …… Circular hole, (154) ……
Reaction force plunger, (154a) …… recess, (156) …… ball, (157) …… V-shaped groove, (158), (258) …… protrusion,
(162), (262) …… Operation groove, (164) …… Coil spring, (166) …… Engagement part, (264) …… Snap ring.

Claims (1)

(57) [Scope of utility model registration request] 1. An input shaft rotated by a steering wheel, an output shaft arranged on the same axis as the input shaft and capable of relative rotation, and a valve member provided on both shafts so as to be integrally rotatable. And a reaction force mechanism provided between the shafts, the reaction force mechanism being slidably fitted in a radial hole formed in one of the shafts. Formed on the outer surface of the reaction force plunger, the ball held in the concave portion provided eccentrically from the center of the outer diameter on the inner side end surface of the reaction force plunger, and the outer surface of the other shaft. In a power steering device including an axial groove in which the ball is pressed by an acting hydraulic pressure, the power steering device is fixed to the outer peripheral side opening of the radial hole by pressure contact with the inner peripheral surface of the radial hole by its own expansion force. spring The power rudder, which is equipped with a material, and is provided with a detent portion at the outer end of the reaction force plunger for engaging with the engagement portion of the spring member to restrict rotation of the reaction force plunger. Device.