JPH032111B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power steering device, and particularly to an improved connection structure between a valve sleeve and a pinion shaft.

FIG. 1 shows an example of a conventional power steering device. A pinion shaft 1 as an output shaft supported by a pinion bearing 2 is connected to a valve sleeve 5 of a control valve 4 by a pin 3.
Further, a torsion bar 7 is connected to the pinion shaft 1 through a pin 6. The other end of the torsion bar 7 is connected to the valve shaft 9 by a pin 8.
Therefore, the pinion shaft 1
and a valve shaft 9 are connected via a torsion bar 7. That is, when a load is applied to the pinion shaft 1 when the valve shaft 9 is rotated, the torsion bar 7 is twisted in response to the load. 10 is a valve housing, a valve sleeve 5 is fitted into the inner periphery of the housing 10, and a valve shaft 9 is fitted into the inner periphery of the valve sleeve 5. The valve shaft 9 has a torsion bar 7 with respect to the valve sleeve 5.
can be rotated by a predetermined angle according to the twist of the This rotation causes the hydraulic pump (not shown) to
Oil is guided from the valve shaft 9 and valve sleeve 5 to the power assist cylinder to assist vehicle steering.

FIG. 2 shows the end of the pinion shaft 1 on the control valve 4 side, and a hole 11 into which the torsion bar 7 is loosely fitted is provided in the end.
Further, in the outer wall 12, openings 13A and 13B are cut out at a predetermined opening angle. Outer wall 1
2 is further provided with a pin hole 14, and the pin 3 is press-fitted into this pin hole 14 in advance. Then, the valve sleeve 5 is inserted into the pinion shaft 1 while being shifted to the right in FIG. 1, and the head of the pin 3 is inserted into the pin hole 5A, thereby connecting the pinion shaft 1 and the valve sleeve 5. Ru.

FIG. 3 shows the end of the valve shaft 9 on the pinion shaft side, and a boss 15 is fitted loosely into the openings 13A and 13B provided in the pinion shaft 1, as shown in FIG. is installed protrudingly. The boss 15 has openings 13A and 13
It has a width across flats corresponding to B. This boss 15
and each surface of the outer wall 12 facing the openings 13A and 13B of the pinion shaft 1, in other words, the stopper surface consisting of the S surface, T surface, U surface, and V surface of the outer wall 12 as a manual stop portion. are facing each other. That is,
In FIG. 4, when the valve shaft 9 is rotated to the right, the stopper surface 15A of the valve shaft 9 comes into contact with the S surface of the outer wall 12, and the stopper surface 15B of the valve shaft 9 comes into contact with the T surface of the outer wall 12, and the pinion shaft is rotated. 1 is rotated. Also, valve shaft 9
When the pinion shaft 1 is rotated to the left, the stopper surface 15B of the valve shaft 9 comes into contact with the U surface of the outer wall 12, and the stopper surface 15A of the valve shaft 9 comes into contact with the V surface of the outer wall 12, and the pinion shaft 1 is rotated.

However, in the conventional power steering device configured in this manner, the valve sleeve 5 is supported on the pinion shaft 1 using the pin 3, and therefore has the following drawbacks. That is, () It is difficult to obtain a shape tolerance (deviation degree, perpendicularity) of the pin hole 14 with respect to the stopper portion of the pinion shaft 1, and it is difficult to match the neutral position of the control valve 4 with the neutral position of the manual stopper portion.

() When removing the pinion bearing 2, it is necessary to remove the pin 3, but since the pin 3 is press-fitted and the valve shaft 9 is inside the pin 3, the pin 3 must be pulled out.
For this reason, the pin 3 is damaged and cannot be reused. It is also possible to remove the valve shaft 9 and drive in the pin 3, but in this case, it takes time to remove the valve shaft 9, which poses a problem in serviceability.

() Due to (), it is difficult to increase the spring constant of the torsion bar to a desired value and obtain a direct steering feeling.

() Pin hole 1 in outer wall 12 of pinion shaft 1
4 is bored, and the cross-sectional area of the outer wall 12 functioning as a manual stop portion is reduced by the amount of the pin hole 14. Further, when the pin 3 is press-fitted into the pin hole 14, internal stress is generated in the outer wall 12. Therefore, due to these two factors, the strength of the outer wall 12 as a stopper portion is insufficient.

An object of the present invention is to provide a power steering device that eliminates such conventional drawbacks.

That is, in the present invention, the shape of the manual stopper part of the output shaft is two manual stopper parts protruding from the end face of the output shaft, each having a stopper surface that is symmetrical in the radial direction of the axis and faces each other, A locking opening having a shape corresponding to the manual stopper portion is formed in the valve sleeve, and the manual stopper portion and the locking opening are connected through a locking member having a shape corresponding to the manual stopper portion and the locking opening. Then, the output shaft and the valve sleeve are connected so that they rotate together.

In the pinion shaft used in the embodiment of the present invention, two manual stopper sections each having a stopper surface are protruded from the end on the control valve side, and the stopper surfaces of each stopper section are faced in parallel. A valve sleeve is loosely fitted into the gap between these two stopper parts, so that the stopper surface of the valve shaft and the stopper surface of the pinion shaft stopper part can come into contact with each other. Torque can be transmitted directly. On the other hand, in the valve sleeve connected to the pinion shaft, a notch having a shape corresponding to the gap formed between the two stopper parts described above is formed at the end thereof on the pinion shaft side. A thrust plate is fitted into this notch, and this plate is held by a snap spring. A thrust plate is fitted into the gap of the pinion shaft to connect the pinion shaft and the valve sleeve.

Regarding the processing of the valve sleeve used in the embodiments of the present invention, the opening and closing control of the valve groove on the inner peripheral surface of the valve sleeve, that is, the passage that supplies oil from the valve sleeve to each cylinder or reservoir tank via the valve shaft, is performed. After machining a notch, the groove to be formed can be machined using the notch as a reference.

In the embodiment of the present invention, the connection structure between the valve sleeve and the pinion shaft has been improved, and in addition to this improvement, the dimensional accuracy of each part of the valve sleeve has been improved, so that the neutral point of the manual stopper and the neutral point of the control valve can be adjusted. can be adjusted with desired accuracy, and as a result, the spring constant of the torsion bar can be made larger than in the past, thereby providing a power steering device with excellent steering feel.

Hereinafter, the present invention will be explained in detail based on the drawings.
Note that the same parts as in FIGS. 1 to 3 are denoted by the same reference numerals, and the explanation thereof will be omitted.

FIG. 5 shows an embodiment of the present invention, and FIG. 6 shows a cross section taken along the line --. In FIG. 5, reference numeral 21 indicates a pinion shaft as an output shaft, and the end portion of this pinion shaft 21 is formed as shown in FIG. 7. That is, a manual stopper part 22 having a stopper surface 22A and a manual stopper part 23 having a stopper surface 23A are formed at the end of the pinion shaft 21. These stopper surfaces 2
2A and 23A face each other in parallel. Note that 24 is a recess into which the torsion bar 7 is loosely fitted;
Reference numeral 25 is a locking portion to which the pinion bearing 2 is locked. In FIG. 5, 26 is a valve sleeve, and as shown in FIG.
At the bottom of the valve sleeve 26, two notches 27 are formed as locking ports in the radial direction of the valve sleeve 26, and on the outer peripheral surface slightly above the bottom of the valve sleeve 26,
A ring groove 28 is carved. Note that 29 is a port, which communicates with a valve groove formed on the inner circumferential surface of the sleeve 26.

Referring again to FIGS. 5 and 6, the thrust plate 31 as a locking member shown in FIG. 9 is fitted into the notch 27 of the valve sleeve 26, and the snap ring 32 is fitted into the ring groove 28. Then, the plane 31 is held by a snap spring 32. The valve sleeve 26 thus constructed is supported by the pinion shaft 21. That is, the two manual stop portions 2 of the pinion shaft 21
A plate 31 is fitted into the gap between 2 and 23. Here, the movement of the thrust plate 31 in the axial direction of the pinion shaft 21 is restricted by the gap between the stepped portion of the valve shaft 9 and the surface on which the stopper portions 22 and 23 of the pinion shaft 21 rise, and thus the valve sleeve Relative movement of the pinion shaft 26 and the pinion shaft 21 in the longitudinal direction is restricted. On the other hand, the valve sleeve 26 and pinion shaft 21
Relative movement in the radial direction between the valve shaft 9 and the valve sleeve 26 is restricted within a range determined by the fit between the valve shaft 9 and the valve sleeve 26.

Referring to FIG. 6, the boss 15 of the valve shaft 9 is loosely fitted into the gap between the stopper surfaces 22 and 23, and the stopper surface 15A of the boss 15 and the stopper surface 22 of the stopper portion 22 of the pinion shaft 21
A, and the stopper surface 15B and stopper surface 23A of the boss 15 are opposite to each other. Therefore, when the valve shaft 9 rotates more than a predetermined amount, the boss 1
The two corners of the stopper surface 15A of No. 5 are in contact with the stopper surface 22A, and the two angles of the stopper surface 15B are in contact with the stopper surface 23A, thereby directly transmitting the torque of the valve shaft 9 to the pinion shaft 21. can.

In the present invention, as can be seen from the embodiments described above, a plate 31 having a shape corresponding to the shape of the stopper parts 22 and 23 is used, and the locking opening 27 of the valve sleeve 26 is made to correspond to the shape of the stopper parts 22 and 23. Shape.

The above-mentioned pinion shaft 21 does not need to have a pin hole for supporting the sleeve, which required high dimensional accuracy as in the conventional case, and instead of the pin hole, it is necessary to make parallel stopper surfaces 22A and 23A facing each other. Manual stopper part 2 having
2 and 23 only need to be formed. In addition, regarding processing of the valve sleeve 26, a notch 27 for the plate is machined, and a valve groove (not shown) etc. can be machined using a broach etc. using this notch 27 as a reference, and the valve sleeve 26 can be machined using a broach or the like. The dimensional accuracy between the notch 27 and the valve groove can be significantly improved compared to the case where the sleeve support pin hole 5A is formed using the groove as a reference. More specifically, the diameter of the conventional pin hole 5A is approximately 3 mm, and when machining such a small diameter pin hole 5A, first a valve groove is machined, and then this valve groove is used as a reference. , the pin hole 5A was machined with a predetermined degree of deviation. However, drilling a small diameter hole with a predetermined degree of deviation requires extremely high precision, and it has been difficult to obtain the desired degree of deviation. Therefore, according to the embodiment of the present invention, the above-mentioned dimensional accuracy can be significantly improved.

Therefore, in addition to the improved connection structure between the valve sleeve 26 and the pinion shaft 21, the dimensional accuracy of each part of the valve sleeve 26 has been improved to improve the neutral point of the manual stopper and the control valve 4.
It becomes possible to align the neutral point with the desired accuracy. As a result, even if the spring constant of the torsion bar 7 is increased, the stress generated in the torsion bar 7 does not vary as in the past, and the spring constant of the torsion bar 7 can be increased while suppressing the stress generated in the torsion bar 7 within the conventional value. As a result, a power steering device with a direct feel can be obtained.

FIGS. 10A and 10B show another example of the plate,
Valve sleeve 26 on the side of plate 41
The four abutting portions 41A to 41D are shaped as shown in the figure so that the rotational angular position of the pinion shaft 21 and the valve sleeve 26 with respect to their axes can be adjusted. That is, as shown in FIG. 10B, the abutting portions 41A and 41C are inclined by an angle θ and protrude, and the abutting portions 41B and 41D are similarly inclined by an angle θ and recessed. Therefore,
The rotation angle positions of the valve sleeve 26 and pinion shaft 21 are adjusted as shown in FIG.
It becomes possible to shift by an angle θ with respect to AX1. In other words, by providing offsets in the contact portions 41A to 41D, the relative angular position between the valve sleeve 26 and the pinion shaft 21 can be easily adjusted.

As explained above, the two manual stopper portions protrude from the end face of the output shaft of the present invention, each having a shape of the manual stopper portion having stopper surfaces facing each other that are symmetrical in the radial direction of the axis thereof, and the manual stopper portion A locking opening having a shape corresponding to that of the valve sleeve is formed in the valve sleeve, and the stopper part and the locking opening are connected through a locking member having a shape corresponding to the stopper part and the locking opening. Since the shaft and the valve sleeve are connected so that they rotate together, the neutral point of the control valve and the neutral point of the manual stopper can be easily aligned. In addition, improving serviceability,
It also contributes to improving the strength of the manual stopper part.

Furthermore, since the valve sleeve has a two-point support structure that is substantially symmetrical about its rotation axis, there is no loss in the rotational force transmitted to the valve sleeve, and the valve sleeve rotates smoothly. Furthermore, since the locking member is supported on four sides with respect to the output shaft, surface pressure is dispersed and wear does not occur, improving the durability of the device.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing an example of a conventional power steering device, Fig. 2 is a perspective view showing the end shape of the pinion shaft, and Fig. 3 is a similar view showing the end shape of the valve shaft. A perspective view, FIG. 4 is a sectional view taken along the - line in FIG. 1, FIG. 5 is a longitudinal sectional view showing an embodiment of the present invention, FIG. FIG. 8 is a perspective view showing the end of the valve sleeve, FIG. 9 is a perspective view showing the thrust plate, and FIG. 10A shows another example of the thrust plate. A perspective view, FIG. 10B is a plan view thereof, and FIG. 11 is a diagram corresponding to FIG. 6,
5 when using the plate shown in Figure 10A
It is a sectional view taken along the line - in the figure. 1, 21... Pinion shaft, 4... Control valve, 5, 26... Valve sleeve, 7
... Torsion bar, 9 ... Valve shaft, 2
2, 23... Stopper portion, 27... Notch (locking opening), 31... Plate (locking member).

Claims (1)

[Claims] 1. A hydraulic pump, a cylinder to which oil from the hydraulic pump is supplied to perform power assist during vehicle steering, and a cylinder that rotates in accordance with the amount of rotation of the steering wheel to control the amount of steering of the vehicle; an output shaft having a manual stopper portion to which rotation of the handle is directly transmitted when the power assist is not performed;
a valve sleeve facing the output shaft and connected to rotate together with the output shaft; a torsion bar extending in the axial direction inside the valve sleeve and facing the output shaft; and a valve shaft connected to the output shaft through the valve shaft, and when the valve shaft is displaced by a predetermined angle or more with respect to the output shaft, the valve shaft contacts the stopper portion, and the rotation of the valve shaft is stopped by the stopper portion. A power steering device that directly transmits power to an output shaft so that when the torsion bar is twisted, a rotational displacement is generated between the valve shaft and the valve sleeve so that oil from the hydraulic pump is guided to the cylinder. In the manual stopper part,
Two manual stopper portions protrude from an end surface of the output shaft in the axial direction of the output shaft, and each of the manual stopper portions has stopper surfaces facing each other that are symmetrical in the radial direction of the shaft center. Further, a locking member having a shape having two symmetrical side surfaces in the radial direction of the axis, which corresponds to the stopper surface, is disposed on the manual stopper portion, and the locking member is configured to engage the valve shaft and the output. It is arranged between the shaft in the axial direction and 2
Fitting between the two manual stopper parts,
The movement of the valve sleeve in the axial direction is restricted, and the valve sleeve has a
The locking member locking opening is formed symmetrically in the radial direction of the axis and has a shape that fits into each side surface at both ends of the side surface of the locking member, and the locking opening allows for: The power steering device according to claim 1, wherein the valve sleeve is connected to the manipulator stop portion via the locking member so as to rotate together with the output shaft. 2. In the power steering device according to claim 1, the locking member is a thrust plate, the thrust plate is held in the locking opening, and the thrust plate is connected to the manual stopper portion. A power steering device characterized in that the power steering device is fitted in a fixed manner. 3. The power steering device according to claim 2, wherein the thrust plate is held on the valve sleeve by a snap spring fitted on the outer peripheral surface of the valve sleeve. 4. The power steering device according to any one of claims 1 to 3, wherein the output shaft is a pinion shaft. 5. In the power steering device according to any one of claims 1 to 4, an offset is provided at a contact portion of the locking member with the valve sleeve so that the valve sleeve and the valve sleeve are in contact with each other. A power steering device characterized in that the relative angular position with respect to a pinion shaft can be adjusted.