JPH0138029B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power steering device with plate type valve functionality.

Conventional power steering devices are provided with rotary or spool type valve actuation mechanisms, but these valve mechanisms themselves are complex and relatively long, and the valve configuration requires high precision. It had the disadvantage of being large and expensive.

The present invention proposes a power steering device having a plate type valve mechanism, which is completely different from the conventional rotary type or spool type valve actuation mechanism which has such drawbacks, and which simplifies the configuration of the valve mechanism. In addition to reducing the size, the pump has oil holes through which hydraulic oil passes, and prevents hydraulic oil from leaking from the oil holes between the plates that are in contact with each other, so that the amount of oil sent out from the pump is effective as a steering assist force. The purpose of the present invention is to provide a power steering device that can be used for various purposes.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of a main part of a power steering device showing an embodiment of the present invention. That is, the piston 1 separates the inside of the cylinder 2 into two working chambers 3 and 4, and the piston 1 is provided with a rack 1a.
It meshes with a sector gear 5a carved in a sector shaft 5 that drives a control link (not shown), and is passed through a supply hole 7 and a discharge hole 8 provided in a rear housing 6 that seals one end of the cylinder 2. This is a power steering device that selectively supplies and discharges hydraulic oil to the working chambers 3 and 4 to assist rotation of the sector shaft 5 connected to the piston 1, and the wormshaft 9 supports the rear housing 6. It penetrates under liquid sealing, one end is connected to the piston 1 by a ball screw 10, and the other end is connected to the rear housing 6 with a bearing 11,
It is rotatably supported via 12. Also,
As shown in FIGS. 2 and 3a, the head 9a at the other end of the wormshaft 9 has a bearing hole 9a, a radial long groove 9c into which a flange 13a of a stubshaft 13 (to be described later) is inserted, and an end face opening. An annular recess 9d is provided, and an annular chamber 9d' whose axial dimension (dimension A in the figure) is controlled is formed in a part of the annular recess 9d. Further, at least one set (two sets in this embodiment) of oil passages 9e, 9f and a supply passage 9g are opened at the end face of the head 9c with a desired pitch diameter, and one oil passage 9f is directly connected to the working chamber 3, and the other oil passage 9e is directly connected to the bearing 1.
The supply passage 9g communicates with the supply hole 7 through the space 12a in which the cylinder 2 is placed, and further through a passage 6a in the rear housing 6 and a passage 2a in the cylinder 2. 9h is wormshaft 9
This is a pin that is implanted in the worm shaft 9 and rotatably connects the worm shaft 9 and a first plate 19, which will be described later, together.

A stub shaft 13 has one end connected to a steering wheel (not shown), and the stub shaft 13 has a bearing 14 placed in the bearing hole 9b of the wormshaft 9 and a rear cover screwed onto the end of the rear housing 6. The worm shaft 9 is rotatably supported by a bearing 16 placed facing the worm shaft 9, and is connected to the worm shaft 9 via a flexible torsion bar 17. 17a and 17b are pins that respectively fix both ends of the torsion bar 17. 18 is a shaft seal that seals the stub shaft 13. Also, the stub shaft 13 has a third
As shown in FIG. b, at least one (two axially symmetrical in the embodiment) radial flanges 13a are provided, and are loosely fitted into the long grooves 9c of the wormshaft 9 with a desired rotational clearance. Therefore, even if hydraulic oil is not supplied to the working chambers 3 and 4 due to a failure of the pump or the like, the rotational force of the steering wheel is transmitted to the wormshaft 9 with a slight play angle, so that the so-called normal operation can be performed. Manual operation is possible. Furthermore, a drive pin 13b is implanted in the shaft portion of the stub shaft 13 in the radial direction, and this drive pin 13b connects the stub shaft 13 and a second plate 20, which will be described later, so as to be integrally rotatable.

19 is an annular recess 9d of the wormshaft 9
The first plate 19 is located inside the worm shaft 9, has an outer diameter smaller than the inner diameter, has one side in contact with the bottom surface thereof, and is connected to the worm shaft 9 by a pin 9h so as to be integrally rotatable with the worm shaft 9. As shown in FIG. 3c, there are at least one pair of holes (19a) into which the stub shaft 13 is loosely fitted, a hole 19b into which the pin 9h is inserted, and which open into the oil passages 9e, 9f of the wormshaft 9, respectively. In this embodiment, two sets of oil passages 19c and 19d and a passage 19e communicating with the supply passage 9g of the worm shaft 9 and having approximately the same diameter as the supply passage 9g are formed. Here, as shown in FIG. 4, the oil passages 19c and 19d have round holes 19c and 19d having diameters approximately equal to the diameters of the oil passages 9e and 9f of the wormshaft, respectively, and rectangular holes that are continuous with these and have a diameter larger than these. Hole 19c ₂ ,1
9d ₂ , and this first plate 19 connects the round holes 19c ₁ , 19d ₁ to the wormshaft oil passages 9e, 9.
It is installed facing f. Note that 19f is an escape groove that allows the driving pin 13b of the stub shaft 13 to pass therethrough.

20 has approximately the same outer diameter as the first plate 19, and is inserted into the stub shaft 13 with one side facing the first plate 19 and the other side facing a third plate 22 (described later), and is connected to the drive pin 13b. This second plate 20 has a central hole 20 for inserting the stub shaft 13, as shown in FIG. 3d.
a, communicates with the supply passage 19e of the first plate 19 together with the insertion hole 20b of the drive pin 13b;
a pair of substantially rectangular oil passages 20c, communicating with the oil passages 19c and 19d of the first plate and opening to the outer periphery;
At least one set (two sets in this embodiment) of notched oil passages 20d and 20e are formed. Here,
As shown in FIG. 5, the oil passages 20c, 20d, and 20e are all oil passages that do not penetrate through one side, and the hydraulic oil, especially the high-pressure hydraulic oil that flows into the oil passage 20c,
It is designed not to act directly on the third plate 22, which will be described later.

Here, in a standard state in which the stub shaft 13, that is, the second plate 20 connected thereto, is not rotated, the oil passage 20c is preferably connected to both the oil passages 19c and 19d of the first plate 19, as shown in FIG. are partially connected with the same opening area, and the oil passage 20d is connected to one oil passage 19c of the first plate 19.
In addition, each of the oil passages 20e opens partially into the other oil passage 19d, preferably with the same opening area. In other words, the oil passage 20c and the oil passage 2
0d or the oil passage 20e covers most of the opening area of the oil passage 19c or the oil passage 19d of the first plate, and preferably the total covered area of the oil passage 19c and the oil passage The total covered area of 19d is made equal.

22 is an annular recess 9d of the wormshaft 9
A third plate 22 is screwed onto the open end of the stub shaft so as to abut against the stepped locking surface 9i to close the annular chamber 9d', as shown in FIG. 3e. 13 Center hole for insertion 22
together with a, the annular recess 9 of said wormshaft 9;
A throttle passage 22 that communicates with the inside of d and the hydraulic oil discharge hole 8.
It has b.

Here, the axial clearance between the first plate 19, the second plate 20, and the third plate 22 must be controlled in order to seal the hydraulic oil and allow the second plate 20 to rotate smoothly. It won't happen.
According to the present invention, the wormshaft 9
Of the annular recess 9d provided at the end, the annular chamber 9
The axial dimension A of d' is measured in advance, and the first plate 19 and second plate 20 accommodated therein are
By controlling the thickness of each plate 19,
20 is selectively accommodated in accordance with the axial dimension A of the annular chamber 9d', and the stepped locking surface 9i of the annular chamber 9d'
By assembling the third plate 22 so as to abut against each other as described above, each plate 19, 20,
The gap between 22 can be easily controlled.

Note that 23 is an annular chamber communicating with the hydraulic oil supply hole 7 and the supply passage 9g of the wormshaft 9, and 24 is a space communicating with the discharge hole 8 and the throttle passage 22b of the third plate. Further, the supply hole 7 and the discharge hole 8 are in communication with a pump and a reservoir (not shown), respectively.

In this configuration, in a standard state in which the steering wheel (not shown) is not rotated, the stub shaft 13 and the second plate 20 connected thereto do not rotate, and the oil passages 19c, 19d of the first plate 19 and The relative position of the second plate 20 with the oil passages 20c, 20d, and 20e is at the standard position shown in FIG.
Therefore, the hydraulic oil supplied from the pump (not shown) is
From the supply hole 7 to the annular chamber 23, the supply passage 9g of the wormshaft 9, and the passage 19e of the first plate 19
reaches the oil passage 20c of the second plate 20 via
Furthermore, the first part is partially opened to the oil passage 20c.
The oil passages 19c and 19d of the plate 19 are reached. These oil passages 19c and 19d communicate with the working chambers 3 and 4 in the cylinder 2 via oil passages 9e and 9f of the worm shaft 9, respectively, so that the hydraulic oil does not try to flow into the working chambers 3 and 4. However, the oil passages 19c and 19d of the first plate 19 are partially connected to the oil passage 20 of the second plate 20 at the same time.
Therefore, the hydraulic oil flowing into the oil passages 19c, 19d of the first plate 19 flows into the annular recess 9d of the wormshaft 9 via the oil passages 20d, 20e of the second plate 20. Finally,
The water is drained from the discharge hole 8 to a tank (not shown) via the throttle passage 22b of the third plate 22 and the space 24, and no hydraulic pressure is generated in the working chambers 3, 4.

On the other hand, with the steering wheel not shown in the diagram, the stub shaft 13
When the wormshaft 9 is rotated clockwise or counterclockwise, the wormshaft 9 connected to the stub shaft 13 via the torsion bar 17 also tries to rotate. Since the piston 1 and the wormshaft 9 are subject to ground resistance from the wheels via a control link (not shown), the piston 1 and the wormshaft 9 are immovable, and a torsion angle is created in the torsion bar 17 so that the wormshaft 9 and the stub shaft 13
That is, relative rotation occurs between the first plate 19 and the second plate 20, which are integral with each other. Then, for example, when the stub shaft 13 is rotated counterclockwise in FIG.
The oil passage 20c of the second plate 20 communicates with the first oil passage 9e, which communicates with one of the working chambers 4.
The opening area of the plate 19 to the oil passage 19 is gradually reduced until it becomes zero, and the oil passage 19 opens to the oil passage 9f communicating with the other working chamber 3.
The opening area for d is increased to allow hydraulic oil to flow into the working chamber 3.
to increase the pressure in the working chamber 3. at the same time,
The oil passage 20d that communicates with the discharge hole 8 is connected to the first plate 1 where the oil passage 9e that communicates with one of the working chambers 4 opens.
The opening area for the oil passage 19c of 9 is increased, and the hydraulic oil in the working chamber 4 is drained into a tank (not shown).
As a result, the piston 1 is moved to the left, thereby assisting the rotation of the sector shaft 5. The same is true when the stub shaft 13 is rotated clockwise; this time, hydraulic oil is supplied into the working chamber 4, and the hydraulic oil in the working chamber 3 is discharged through the oil passage 20e of the second plate. , move the piston 1 to the right. In this way, it is possible to effectively assist the wheel steering operation by rotating the steering wheel (not shown).

In this case, since the oil passages 19c and 19d of the first plate 19 are configured to open into the oil passages _9e and 9f of the wormshaft 9 at their round holes 19c 1 and 19d ₁ , these oil passages 19c , 19d, 9e, and 9f leaking between the first plate 19 and the worm shaft 9 can be effectively suppressed. Furthermore, by configuring the third plate side of the oil passages 20c, 20d, and 20e of the second plate 20 to be closed, the hydraulic oil passing through these oil passages 20c, 20d, and 20e is connected to the second plate 20 and the third plate side. 3 plate 2
2 can be effectively prevented from leaking between the two.

In addition, the worm shaft 9 of the first plate 19
Around the round holes 19c ₁ and 19d ₁ on the side facing the
By fitting the O-ring 25 as shown in FIGS. 6a and 6b, leakage of hydraulic oil between the first plate 19 and the wormshaft 9 can be completely prevented.

Thus, from the pump to each of the working chambers 3 and 4, the worm shaft 9 and the first plate 19
and between the second plate 20 and the third plate 2
This effectively prevents the hydraulic oil from leaking wastefully between the pump and the pump and reduces the hydraulic effect, thereby reducing the amount of hydraulic oil delivered from the pump, and as a result, making the pump more compact. I can do it. Note that by forming the oil passages 19c and 19d of the first plate 19 so that they become narrower toward both ends in the circumferential direction, the initial hydraulic characteristics when opened and closed by the second plate 20 are relaxed. It can be changed into a crab. Here,
Since the hydraulic oil is gradually switched to the working chambers 3 and 4 as described above, the assisting action by the hydraulic oil pressure increases gradually as the steering wheel turns, resulting in power steering that provides an extremely excellent steering feeling. You can get the equipment. In addition, the plates 19 and 20 that provide oil passages for selectively supplying and discharging hydraulic oil can be press-formed from a thin steel plate or made of sintered material, so that the axial length can be shortened. As a result, a small and inexpensive power steering device can be obtained.

Further, as described above, the axial clearance between the second plate 20, the first plate 19, and the third plate 22 is set as desired in order to seal the hydraulic oil and make the rotation of the second plate 20 smooth. The gap must be adjusted to the following by measuring the axial dimension A of the annular chamber 9d' in advance and
The thicknesses of the plate 19 and the second plate 20 are controlled, and each plate 19, 20 is selectively housed in accordance with the axial dimension A of the annular chamber 9d', and the stepped locking surface of the annular chamber 9d' is By assembling the third plate 22 against 9i,
The gaps between the plates 19, 20, 22 can be easily controlled and assembly is simplified.

Additionally, in general, hydraulic equipment uses valves to throttle the flow of hydraulic oil and generate hydraulic pressure, but at this time, the flow velocity of the hydraulic oil increases at the throttle, causing cavitation and fluid noise. sound)
Or vibration may occur. As a well-known measure against such problems, it is effective to provide a suitable orifice in the drain passage downstream of the constriction and to slightly increase the pressure in the drain passage. According to the present invention, the oil passages provided in each plate are selectively constricted by the relative rotation of the first plate 19 and the second plate 20,
In a structure that generates hydraulic pressure in each of the working chambers 3 and 4, oil passages 20d and 20e of the second plate 20 are opened between the annular chamber 9d', which is a drain passage downstream of the throttle part, and the discharge hole 8. are in communication via a throttle passage 22b provided in the third plate 22, and due to the orifice effect of the throttle passage 22b, the pressure in the annular chamber 9d' becomes slightly higher than the pressure in the discharge hole 8 portion. Therefore, the above-mentioned problems peculiar to hydraulic equipment can be advantageously solved. Further, since the throttle passage 22b only generates a slight pressure in the annular chamber 9d', the pressure in the space 24 sealed by the seal 18 downstream of this passage is equal to the pressure in the discharge hole 8. Since the pressure is approximately the same as atmospheric pressure, the sealing effect of the seal 18 is enhanced, and the hydraulic oil can be sealed with a relatively low tension force against the stub shaft 13, so that the rotation of the stub shaft 13 is made smooth. Can be done.

Although an example has been described in which two sets of oil passages communicating with the working chambers 3 and 4 are provided in each of the worm shaft 9, the first plate 19, and the second plate 20, only one set each may be provided.

As explained above, according to the present invention, there is provided a wormshaft in which an annular recess is formed and an oil passage and a hydraulic oil supply passage communicating with each of the two working chambers are opened, and a stub that engages with the wormshaft. a shaft, a round hole located within an annular recess of the wormshaft, rotatable therewith, communicating with each oil passage of the wormshaft, having approximately the same diameter as the oil passage, and an enlarged diameter extending therefrom; a first plate having a passage communicating with an oil passage and a supply passage formed of a rectangular hole, and a third plate having a throttle passage communicating with the inside of the annular recess of the wormshaft and the discharge passage and closing the annular recess. and a passageway located between the first plate and the third plate, which is rotatable together with the stub shaft, and which communicates with the oil passage of the first plate and is closed on the third plate side, and an annular recess. and a second plate having an oil passage communicating with the second plate, and the relative rotation of the first plate and the second plate increases the opening area of each oil passage of the second plate with respect to the respective oil passage of the first plate. In addition, the selective supply and discharge of hydraulic oil to the two working chambers is controlled so that leakage between the wormshaft and the first plate and between the first plate and the second plate is reduced. In addition to providing a smooth and excellent operating feel, the valve mechanism is simple, easy to assemble, and is compact.
Moreover, an inexpensive power steering device can be obtained.

In addition, by reducing the leakage of the hydraulic oil, the amount of hydraulic oil sent out from the pump can be reduced, and therefore the output of the pump can be reduced, making it possible to make it smaller and more economical. Benefits such as:

[Brief explanation of drawings]

FIG. 1 is a sectional view of the main parts of the power steering device of the present invention,
Figure 2 is a sectional view taken along the - line in Figure 1, Figure 3a is a perspective view of the head of the wormshaft, Figure 3b is a perspective view of the main parts of the stubshaft, and Figure 3c is a perspective view of the first plate. , FIG. 3 d is a perspective view of the second plate, FIG. 3 e is a perspective view of the third plate, FIGS. 4 a and b are front and rear views of the first plate, and FIG. 4 c is a perspective view of the third plate. - line sectional view of a, Fig. 5 a and b are the second
Front and back views of the plate, Figure 5c is the fifth
6a is a rear view showing another embodiment of the first plate, and FIG. 6b is a sectional view taken along the line 6a in FIG.
FIG. 1... Piston, 2... Cylinder, 3, 4...
Working chamber, 5... Sector shaft, 7... Supply hole,
8...Discharge hole, 9...Wormshaft, 9d...
...Annular recess, 9e, 9f...oil passage, 9g...supply passage, 13...stub shaft, 13a...flange, 17...torsion bar, 19...first plate, 19c, 19d...oil passage, 19c ₁ ,19
d ₁ ... Round hole part, 19c ₂ , 19d ₂ ... Rectangular hole part, 1
9e...oil passage, 20...second plate, 20c,
20d, 20e...oil passage, 22...third plate, 22b...throttle passage.

Claims (1)

[Claims] 1 In a power steering device that selectively supplies and discharges hydraulic oil to two working chambers in a cylinder separated by a piston, and assists rotation of a sector shaft connected to the piston, one end of the cylinder is penetrates under a liquid seal, one end is screwed to the piston, and the other end is rotatably supported by one end of the cylinder,
A long groove in the radial direction and an annular recess opening in the end surface are formed on the other end side, and at least one set of oil passages communicating with each of the working chambers and a supply passage communicating with the hydraulic oil supply hole are formed. a wormshaft that opens; a stubshaft having a flange that engages with a long groove of the wormshaft with a gap in the rotational direction; a first plate having an oil passage communicating with each oil passage and consisting of a round hole having approximately the same diameter as the oil passage and an enlarged rectangular hole continuous with the oil passage; and a passage communicating with the supply passage of the wormshaft; A third plate, which has a throttle passage communicating between the inside of the annular recess of the wormshaft and a discharge hole for the hydraulic oil, and which closes an open end of the annular recess, and is located between the first plate and the third plate. a first plate that is rotatable integrally with the stub shaft, and has at least one set of oil passages that communicate with the oil passage of the first plate and that are closed on the third plate side and that communicate with the annular recess, respectively; Consisting of two plates, the relative rotation of the first plate and the second plate changes the opening area of the oil passage of the second plate relative to the oil passage of the first plate, and supplies hydraulic oil to the two working chambers. A power steering device characterized by controlling exhaust.