JPH0144392Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an improvement of integral power steering used in vehicles and the like.

Integral power steering, which has been widely used as a steering device for vehicles, is, for example, as shown in Fig. 1, which is housed in a gearbox 1a that also serves as a power cylinder, and is installed in a ball nut 7a that serves as a piston via a ball. Hollow worm shaft 2 as a steering member that engages and rotates
a is pivotally supported, and a torsion bar 4a for maintaining a handle feeling inside the hollow worm shaft 2a.
An inner valve member 8 is fixed at one end and connected to the handle shaft at the end of the torsion bar 4a on the handle side.
A stub shaft 3a to which a is fixed and is steered is coupled to the worm shaft 2a, and a rotary valve whose flow path is switched by rotation of the handle shaft to control the flow of pressure fluid is attached to the outer circumferential surface 21a of the worm shaft 2a. The inner peripheral surfaces of the hollow cylindrical outer valve member 5a are fitted, and one end of the pin 6a press-fitted into the worm shaft 2a is connected to the pin 6a of the valve member 5a.
They are inserted into a U-shaped groove 51a having a groove width that fits with the two, and are fixed to each other so that they cannot rotate relative to each other.

Therefore, by steering the handle shaft, the inner valve member 8a rotates with the twisting of the stub shaft 3a and the torsion bar 4a, and the end face of the ball nut 7a is pressed by the flow of pressure fluid controlled by this rotation. The ball nut 7a is moved left and right to reduce the manual steering force of the steering wheel, but there is a difference between the hole diameter of the worm shaft 2a into which the pin 6a is press-fitted and the diameter of the pin 6a. If the predetermined dimensions cannot be obtained due to processing defects or the like, there is a risk that the pin may come off, and countermeasures have been required.

This design compensates for the above-mentioned drawbacks of conventional products, and even if there is a processing defect in both dimensions, the pin will never fall off, and therefore the steering force due to fluid pressure will not be lost, ensuring quality. The present invention provides a power steering device.

Next, a typical embodiment of the power steering device according to this invention shown in FIGS. 2 and 3 will be explained. The figures each show the relationship between the worm shaft stub shaft and the valve member as the steering member according to this invention. 1 is a vertical cross-sectional view and a cross-sectional view, in which reference numeral 1 indicates a gearbox, 2 indicates a worm shaft, 21 indicates an outer peripheral surface of the worm shaft 2, 3 indicates a stub shaft, 4 indicates a torsion bar, 5 indicates a valve member, and 51 indicates a valve member. 5 is a U-shaped groove, 6 is a stepped pin, l is the length of the small diameter side of the stepped pin 6, and t is the inner peripheral surface 2 of the worm shaft 2.
2 and the outer peripheral surface 31 of the stub shaft 3 in the radial direction.

First, referring to FIG. 2, this figure is a cross-sectional view of the main part of the embodiment of the power steering device according to this invention.
There is a gap t in the radial direction between the inner circumferential surface 22 of the worm shaft 2 as a steering member coupled to the worm shaft 2 and the outer circumferential surface 31 of the stub shaft 3 that is fitted concentrically with the worm shaft 2. A hollow cylindrical outer valve member 5 is fitted onto the outer peripheral surface 21, and a small diameter portion of a stepped pin 6 having a length l press-fitted into the worm 2 forms a U-shaped groove provided in the outer valve member 5. 5
1 and fixed so that they cannot rotate relative to each other.

Further, the total length of the stepped pin 6 is the same as that of the worm shaft 2.
a radial gap t provided between the wall thickness of the press-fitted portion of the pin and the outer circumferential surface of the stub shaft 3 that fits concentrically with the inner circumferential surface of the worm shaft 2 with a gap; It is formed longer than the sum of .

FIG. 3 shows a cross section taken along line E-E in FIG. 2 of the same embodiment, and shows the relationship among the worm shaft 2, stub shaft 3, valve member 5, and stepped pin 6. The large diameter 6 indicates that it is larger in the direction of the valve member 5 than the width of the U-shaped groove 51 of the valve member 5.

As mentioned above, the power steering device based on this invention is
Worm shaft 2 as a steering member and the valve member 5
A pin 6 for fixing the worm shaft 2 is formed in a stepped manner, and the total length of the pin 6 is equal to the thickness of the press-fitted portion of the pin 6 of the worm shaft 2 and the thickness of the press-fitted portion of the pin 6 of the worm shaft 2.
Since the pin 6 is formed longer than the sum of the radial clearance t between the inner circumferential surface 22 of the stub shaft 3 and the outer circumferential surface 31 of the stub shaft 3, the pin 6 will never fall off toward the stub shaft 3. Furthermore, since the diameter of the large diameter of the stepped pin 6 is larger than the width of the U-shaped groove 51 provided in the valve member 5, the pin 6 will never come off in the direction of the valve member 5, resulting in stable quality. can be ensured.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of an embodiment of a conventionally used power steering device, and FIGS. 2 and 3 are sectional views of main parts of an embodiment of a power steering device according to this invention. In the figure, 1 is the gearbox, 2 is the worm shaft,
3 is a stub shaft, 4 is a torsion bar, 5 is a valve member, and 6 is a pin.

Claims (1)

[Scope of utility model registration request] The outer circumferential surface of the stub shaft is concentrically fitted with a gap in the radial direction to the inner circumferential surface of a steering member that steers by rotation, and a hollow cylindrical shape is formed on the outer circumferential surface of the fitting portion of the steering member. In an integral power steering system, the inner peripheral surfaces of the outer valve members are fitted together, and the steering member and the outer valve member are fixed so as not to rotate relative to each other by a pin press-fitted into the steering member. The valve member side is a stepped pin having a smaller diameter, and the length of the pin is longer than the sum of the thickness of the press-fitted portion of the pin of the steering member and the radial clearance. power steering.