JPH08142890A - Power steering - Google Patents

Abstract

PURPOSE: To provide a power steering inexpensive with high reliability without using an electric signal. CONSTITUTION: A sleeve 6 is provided around a rotary spool 5 linked with a steering wheel H, and a pair of valve parts for performing the dividing control of a pump discharge fluid according to the steering of the steering wheel H are provided on the diameter line of the rotary spool 5 and sleeve 6. The rotary spool 5 and the sleeve 6 are provided with a first cylinder variable throttle and a second cylinder variable throttle, enlarged in the opening according to the steering of the steering wheel H, on the way of communicating the first output port and second output port of the valve parts with the first cylinder chamber 23a and second cylinder chamber 23b of a power cylinder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power steering system having a rotary type control valve for controlling a flow division of fluid by relative rotational displacement of a rotary spool and a sleeve.

[0002]

2. Description of the Related Art As a conventional power steering apparatus, for example, there is one shown in FIG. Knuckle arms 5 attached to the left and right tires 51 and 52, respectively
3, 54 are connected to a rack shaft 57 via side rods 55, 56. The rack formed on the rack 57 shaft engages with the pinion formed on the pinion shaft 60 which is rotated by the steering shaft 59 integrally connected to the handle H. A cylinder piston 62, which is incorporated in the power cylinder PC so as to be movable in the axial direction, is integrally attached to the rack shaft 57.

Steering shaft 59 and pinion shaft 6
A control valve 63 is provided between 0. The control valve 63 is
First composed of variable diaphragm parts 63a, 63b connected in series
Variable throttling parts 63c, 63, which are also connected in series with the valve assembly
and a second valve set consisting of d. According to the rotation of the handle H, the apertures of the variable throttle parts 63a and 63b change in opposite directions. Similarly, the opening degrees of the variable throttle portions 63c and 63d change in opposite directions according to the rotation of the handle. Further, the first valve set and the second valve set have opposite opening changes. Variable diaphragm unit 63a
The inlet ports 69 on the upstream side of 63 and 63c are connected to the pump P, and the downstream sides of the variable throttle units 63b and 63d are connected to the tank T. Further, the variable diaphragm units 63a and 63b
Is connected to the first cylinder chamber 61a of the power cylinder PC via the cylinder passage 64, and the second output port 71 in the middle of the variable throttle portions 63c and 63d is connected to the cylinder passage 65. It is connected to the second cylinder chamber 61b of the power cylinder PC via. Further, in the cylinder passage 64, the first cylinder variable throttle 6
6 and a second cylinder variable throttle 67 in the cylinder passage 65.
Is provided. These cylinder variable throttles 66 and 67 are connected to an electronic control unit 68, and their opening degrees are changed according to a signal from the electronic control unit 68.

Next, the operation of this conventional example will be described. When the handle H is turned to the right, the variable throttle parts 63b and 63c
As the opening degree of the variable throttle portions 63a and 63a increases.
It is assumed that the opening degree of d is small. Therefore, the oil discharged from the pump is guided to the variable throttle portion 63c side and also to the second cylinder chamber 61b through the cylinder passage 65. At the same time, the pressure oil is guided to the port 70 through the cylinder passage 64 on the side of the first cylinder chamber 61a, and flows to the tank T while flowing to the side of the variable throttle valve 63b.
That is, since the hydraulic pressure on the second cylinder chamber 61b side increases and the hydraulic pressure on the first cylinder chamber 61a side decreases, the cylinder rod 62 moves to the left in the drawing, and the side rods 55 and 56 and the knuckle arm 53. 54, the assist force is applied to the tires 51, 52 in the right direction in the figure. When the handle H is turned to the left, conversely, the opening amounts of the variable throttle parts 63a and 63d increase and the opening amounts of the variable throttle parts 63b and 63c decrease.
Then, applying the assisting force in the leftward direction in the figure is the same.

When the handle H is in the neutral position, the pump-side variable throttle parts 63a and 63c and 63b and 63d maintain the same opening. Therefore, the discharge oil of the pump communicates with the tank via the first valve set and the second valve set, and the same hydraulic pressure is introduced into the chambers 61a and 61b.
The tires 51 and 52 keep straight. Here, when the steering wheel is neutral, the opening degree of the variable cylinder throttles 66, 67 is kept to a minimum by the electronic control unit 68. At this time, the cylinder chambers 61a and 61b are filled with the same pressure and low hydraulic pressure. And the tire side 51, 52
When some external force is applied from the cylinder variable throttle 6
6 and 67, this force can be attenuated and the straight traveling can be stabilized. When steering the steering wheel H,
The opening degrees of the variable cylinder throttles 66 and 67 are set to such an extent that the responsiveness of the cylinder 61 to the steering wheel H steering does not deteriorate.
And, it is adjusted so as to obtain the damping effect against the external force. As described above, in the conventional power steering apparatus, the opening degrees of the first and second cylinder variable throttles 66 and 67 are adjusted by the electronic control unit 68 according to the traveling state.

[0006]

In the conventional power steering system as described above, the opening degrees of the first and second cylinder variable throttles 66 and 67 are adjusted by the electronic control unit 68. Therefore, the entire apparatus becomes complicated and costly, and there is a problem in reliability because an electric signal is used. An object of the present invention is to provide an inexpensive and highly reliable power steering device without using electric signals.

[0007]

According to the present invention, a sleeve is provided around a rotary pool associated with a steering wheel, and the relative positions of the rotary pool and the sleeve are changed according to the turning of the steering wheel to guide them to a power cylinder. A power steering device for controlling a fluid is assumed. On the premise of the above power steering device, the present invention provides a sleeve having a pair of inlet ports located on the diameter line thereof and connected to a pump, and one side with respect to the pair of inlet ports as a reference, A pair of opposing first output port grooves, located on the other side with respect to the pair of inlet ports as a reference, and a pair of opposing second output port grooves, located approximately 90 degrees offset from the inlet port, The first and second relay ports facing each other, the first passage groove located on both sides of the first relay port, and the second passage groove located on both sides of the second relay port are formed. Is always connected to the pair of inlet ports, and when the steering wheel is in the neutral position, the pair of linking grooves for communicating the inlet port and the output port grooves on both sides of the inlet port and the pair of linking grooves on both sides of each In addition, when the handle is neutral, the four return grooves that communicate with the output ports and return the fluid to the tank, and when the handle is neutral, the first communication grooves that communicate the first relay ports with the first passage grooves on both sides thereof, A first communication passage that forms a second communication groove that communicates the second relay port with the second passage grooves on both sides thereof at the time of neutrality, and that connects the first relay port to the pair of first output port grooves. ,
A second link passage connecting the second relay port to the pair of second output port grooves, a first cylinder passage connecting the first passage groove to the first cylinder chamber of the power cylinder, and a second passage groove of the power cylinder. A second cylinder passage connected to the second cylinder chamber is provided, and when the relative position of the rotary pool and the sleeve is changed by steering the handle, the first output port groove or the second output port groove is depending on the relative position. With the opening of either one of the above and the inlet port increasing,
The opening degree of the other output port groove and the return groove becomes large, the pump discharge fluid is guided to either the first communication passage or the second communication passage, and the fluid of the other communication passage is guided to the return passage. Further, according to the turning of the steering wheel, a first cylinder throttle formed by combining the first relay port, the first passage groove and the first communication groove, and the second relay port, the second passage groove and the second The second cylinder throttle, which is formed by the communication groove and the second groove, is characterized in that the opening thereof increases.

[0008]

In the power steering apparatus of the present invention, when the steering wheel is neutral, a low pressure fluid having the same pressure is introduced into both chambers of the power cylinder. Further, since the opening degrees of the first and second cylinder variable throttles are minimized, it is possible to stabilize straight running even if an external force is applied.
Then, when the steering wheel is steered, the fluid from the pump is guided to one of the first and second cylinder variable throttles according to the steering wheel steering, and the first and second cylinder variable throttles cut off the steering wheel. Since the opening degree is increased according to the condition, the amount of oil flowing into the power cylinder is increased, and the steerability of the steering wheel and the power cylinder can be improved.

[0009]

1 to 5, a steering shaft 2 is inserted into a casing 1, and the steering shaft 2 and a pinion shaft 3 are connected by a torsion bar 4. Then, the rotary spool 5 is integrally formed on the steering shaft 2, and the sleeve 6 is formed around the rotary spool 5.
Are rotatably fitted relative to each other, and the sleeve 6 is adapted to rotate integrally with the pinion shaft 3. The rotary spool 5 and the sleeve 6 form a rotary type control valve. The pinion 3a formed on the pinion shaft 3 is engaged with the rack 7a formed on the rack shaft 7. As shown in FIG. 2, the sleeve 6 is formed with a pair of input ports 8 and 9 at positions opposed to each other on the diameter line of the sleeve. Further, in the vicinity of both sides of each of the input ports 8 and 9, at positions symmetrical with respect to the input ports 8 and 9,
The output port grooves 10, 11 and 12, 13 are formed. The first output port groove 10 and the first output port groove 12 are located at positions opposite to each other on the sleeve diametric line, and the second output port groove 1
1 and 13 are located on the sleeve diametric line at positions facing each other.

The rotary spool 5 is formed with a pair of linking grooves 25 and 26 at positions opposed to each other on the diameter line. When the handle is in the neutral position, that is, when the rotary spool is in the neutral position shown in FIG. 2, the input port 8 and the output port groove 1 are connected via the linking groove 25.
0 and 11 are communicated with each other, and the input port 9 and the output port grooves 12 and 13 are communicated with each other through the linking groove 26. Further, the rotary spool 5 has four return grooves 27 to 30.
The return grooves 27 to 30 are always in communication with the return hole 31 formed in the rotary spool 5, while the return hole 31 is connected to the return passage 32 connected to the suction port of the pump P. . Then, in the neutral state shown in FIG. 2, the return grooves 27 to 30 are respectively output port grooves 10 to 1.
It communicates with 3.

Further, the sleeve 6 has the input port 8 described above.
9 and 9, the first relay port 18 and the second relay port 17 facing each other are formed at positions shifted by approximately 90 degrees.
First passage grooves 37, 38 and second passage grooves 35, 36 are formed in symmetrical positions with respect to the relay ports 18 and 17, respectively, in the vicinity of both sides of the relay ports 17 and 18, respectively. These passage grooves 35 and 37 are located at positions facing each other on the sleeve diameter line, and the passage grooves 36 and 38 are also positioned at positions facing each other on the sleeve diameter line.
In addition, the rotary spool 5 has the above-mentioned connecting grooves 25, 2
6, and a first communication groove 34 and a second communication groove 33 facing each other are formed at positions where their phases are shifted by about 90 degrees. The second communication groove 33 is in constant communication with the second relay port 17, and at the time of neutral shown in FIG.
7 communicates with the second passage grooves 35 and 36. Similarly,
The first communication groove 34 communicates with the first relay port 18, and at the neutral time shown in FIG.
To the first passage grooves 37 and 38.

The input ports 8 and 9 communicate with each other via an input passage 14, and the input passage 14 is connected to the discharge port of the pump P. Also, the first
First output ports 10a, 12 of the output port grooves 10, 12
The a communicates with the first communication passage 15, and the first communication passage 15 communicates with the first relay port 18.
Similarly, the first output port 1 of the second output port groove 11, 13
1a and 13a communicate with each other through the second link passage 16, and the second link passage 16 communicates with the second relay port 17. Further, the first passage grooves 37, 38 are
While communicating with the first cylinder chamber 23a of the power cylinder PC via the cylinder passage 24, the second passage grooves 35, 36 are provided.
Is the power cylinder PC through the second cylinder passage 22.
Of the second cylinder chamber 23b.

FIG. 3 specifically shows each throttle of the rotary control valve described above on the same sectional view as FIG. More specifically, the connection groove 25 and the first output port groove 1
The diaphragm constituted by 0 is a1, and the diaphragm constituted by the connecting groove 26 and the first output port groove 12 is a2. These diaphragms a1 and a2 have the same characteristics, and the diaphragms a1 and a2 together constitute a variable diaphragm section A. Similarly, the diaphragm c1 formed by the link groove 25 and the second output port groove 11, the link groove 26, and the second groove
It is assumed that the variable aperture section C is configured in combination with the aperture c2 formed by the output port groove 13. The variable throttle parts A and C maintain the same opening when the steering wheel is neutral. Further, when the handle is turned to the right, the opening of the variable throttle C becomes smaller and the opening of the variable throttle C becomes larger. On the contrary, when the handle is turned to the left, the opening of the variable throttle A increases and the opening of the variable throttle C decreases. As described above, these variable throttle parts A and C have the same opening change characteristics, although the opening changes are opposite.

The diaphragm constituted by the second output port groove 11 and the return groove 28 is designated as b1, and the diaphragm constituted by the second output port groove 13 and the return groove 30 is designated as b2. The diaphragms b1 and b2 have the same characteristics, and the diaphragm b
It is assumed that 1 and b2 are combined to form the variable diaphragm unit B. Similarly, the diaphragm d1 formed by the first output port groove 10 and the return groove 27 and the corresponding diaphragm d2 formed by the first output port groove 12 and the return groove 29 are combined to form the variable diaphragm portion D. It shall be. The variable throttle parts B and D maintain the same opening when the steering wheel is neutral. Further, when the handle is turned to the right, the opening of the variable throttle portion B becomes smaller and the variable throttle D
On the contrary, when the handle is turned to the left, the opening of the variable throttle B increases and the opening of the variable throttle D decreases. In this way, these variable diaphragm parts B and D
Although the change in the opening is opposite, the characteristics of the change in the opening are the same.

On the other hand, the diaphragm formed by the second communication groove 33 and the second passage groove 35 is designated as e1, and the diaphragm formed by the second communication groove 33 and the second passage groove 36 is designated as e2. The apertures e1 and e2 have the same opening when the steering wheel is in the neutral position, and the apertures e1 and e2 together form the second cylinder variable aperture E. Similarly, the aperture formed by the first communication groove 34 and the first passage groove 37 is f1, and the aperture formed by the first communication groove 34 and the first passage groove 38 is f2. The apertures f1 and f2 have the same opening when the steering wheel is in the neutral position, and the apertures f1 and f2 together form the first cylinder variable aperture F. The variable diaphragm portions A, B, C, D described above and the cylinder variable diaphragm E,
F is shown in FIG. 4 as an equivalent circuit diagram. Then, as can be seen from FIG. 4, the first valve set is changed by the variable throttle parts A and B.
The variable throttle portions C and D form a second valve set.

Next, the operation of the power steering device will be described. When the handle is in the neutral position, the relative positions of the rotary spool 5 and the sleeve 6 are as shown in FIGS. At this time, the discharge oil of the pump P guided to the input ports 8 and 9 is guided to the connecting grooves 25 and 26, and also through the throttles a1, a2 and c1, c2, the output port grooves 10, 11 and 12, Pour into 13. In addition,
At this time, the diaphragms a1, a2 and c1, c2 all maintain the same opening. Furthermore, the output port grooves 10, 11
The oil that has flowed into the fuel cells 12 and 13 flows into the return grooves 27 to 30 through the throttles b1 and b2 and d1 and d2, and is returned to the return passage 32 through the return hole 31. At this time, the diaphragms b1, b2 and d1, d2 all maintain the same opening. At this time, the oil in the output port grooves 10, 11 and 12, 13 is guided to the relay ports 17 and 18 through the first and second connecting passages 16 and 15. Then, the oil introduced into the communication grooves 33 and 34 is
Via the diaphragms e1, e2 and f1, f2, the passage groove 35,
Pour into 36 and 37,38. At this time, the throttles e1, e2 and f1, f2 all maintain the same opening degree, and the opening degrees of the cylinder variable throttles E and F are minimum. Then, this oil is introduced into the cylinder chambers 23a and 23b through the cylinder passages 22 and 24.

This operation will be described with reference to the equivalent circuit of FIG.
When the steering wheel is neutral, the openings of the variable throttle parts A and C are the same, and the openings of the variable throttle parts B and D are also the same. Therefore, the oil discharged from the pump is passed through the first valve set including the variable throttle units A and B connected in series and the second valve set including the variable throttle units C and D similarly connected in series. Communicate with the tank T. At this time, the chamber 23 of the cylinder 23
Since the pressures in a and 23b are the same, straight traveling is maintained without steering assist. Further, since the low-pressure hydraulic pressure is satisfied, even if some external force is applied from the tire side, this force is attenuated by the first and second cylinder variable throttles F and E, and the straight traveling can be stabilized. it can.

Next, when the handle is turned to the right from the neutral position of the handle, the rotary spool 5 rotates in the direction of arrow K as shown in FIG. 5, and the relative position of the rotary pool 5 and the sleeve 6 is as shown in FIG. Changes to. At this time,
As the apertures of the diaphragms c1 and c2 increase,
And the opening degree of a2 becomes small. Therefore, a large amount of the pump discharge oil guided to the connecting grooves 25 and 26 flows into the second output port grooves 11 and 13 in accordance with the openings of the throttles c1 and c2. Further, since the openings of the throttles b1 and b2 are small, the oil flowing into the output port grooves 11 and 13 is
It is guided to the second communication groove 33 via the communication passage 16. At this time, the opening of the diaphragm e1 is small,
Since the diaphragm e2 is large, the opening degree of the second cylinder variable diaphragm E is eventually large. That is, the oil in the second communication groove 33 passes through the second cylinder passage 22 and more pressure oil than in the neutral state of the handle is guided to the second cylinder chamber 23b.

At the same time, since the openings of the throttles d1 and d2 are increased, the oil in the first output port groove 10 is returned to the return groove 2
7 and flows into the return hole 31. Since the diaphragm f2 is now large, the first cylinder chamber 23
The oil in a is the first cylinder passage 24 → throttle f2 → first communication groove 34 → first communication passage 15 → first output port groove 10,
12 → diaphragms d1, d2 → return grooves 27, 29 to be guided to the return hole 31. Therefore, the hydraulic pressure in the second cylinder chamber 23b increases and the hydraulic pressure in the first cylinder chamber 23a decreases, and the cylinder rod moves to assist steering. It should be noted that even when the handle is turned to the left, the operation is the same as that described above, and a detailed description thereof will be omitted.

This operation will be described with reference to the equivalent circuit of FIG.
When the handle is turned to the right, the opening of the variable throttle A becomes smaller and the opening of the variable throttle C becomes larger. Therefore, the oil discharged from the pump is guided to the variable throttle portion C side and also to the cylinder variable throttle E through the second link passage 16. Here, the second cylinder variable aperture E
Since its opening degree is increased according to how the handle is cut, it flows into the second cylinder chamber 23b through the second cylinder passage 22.

At the same time, the opening degree of the first variable throttle portion D becomes smaller and the opening degree of the variable throttle portion B becomes larger. Further, since the opening degree of the first cylinder variable throttle F is increased according to how the handle is cut off, the first cylinder variable throttle F passes through the first cylinder passage 24 and the first link passage 15 to reach the first output ports 10a, 12a. Be guided. Then, it is guided to the tank T via the variable throttle unit B. That is, the hydraulic pressure on the side of the second cylinder chamber 23b increases and the hydraulic pressure on the side of the first cylinder chamber 23a decreases.
The cylinder rod inside moves to the left in the figure to give an assist force to the steering of the steering wheel. When the handle H is turned to the left, on the contrary, the openings of the variable throttle parts A and D become large and the openings of the variable throttle parts B and C become small.
Then, applying the assisting force to the steering that turns the steering wheel to the left is the same.

As described above, when the steering wheel is neutral,
The first and second cylinder variable throttle portions E and F are minimized, and the opening degree thereof is increased according to how sharp the handle is. Therefore, when the steering wheel is neutral, even if an external force is applied from the tire, straight traveling can be stabilized, and when the steering wheel is turned, the power cylinder P
The amount of oil flowing into C becomes large, and the followability of the steering wheel and the power cylinder can be improved. In this way, inexpensive and without using electrical signals,
The reliability can be improved. The opening characteristics of the throttle portions E and F may be determined in consideration of the damping effect when some external force is applied from the tire side and the steerability of the steering wheel and the power cylinder. Although the rack-and-pinion type power steering device is described in this embodiment, it goes without saying that the present invention is also applied to a worm nut type power steering device.

[0023]

According to the present invention, it is possible to provide an inexpensive and highly reliable power steering device without using an electrical signal.

[Brief description of drawings]

FIG. 1 is a sectional view of a power steering device according to an embodiment of the present invention.

FIG. 2 is a diagram showing the rotary valve when the steering wheel is in the neutral position in the power steering device of the embodiment.

FIG. 3 is a diagram specifically showing each throttle of the rotary valve on the same sectional view as FIG.

FIG. 4 is an equivalent circuit diagram of the power steering device of the embodiment.

FIG. 5 is a diagram showing a rotary valve when the steering wheel is turned to the right in the power steering device of the embodiment.

FIG. 6 is an equivalent circuit diagram of a conventional power steering device.

[Explanation of symbols]

 5 rotary spool 6 sleeve 8 and 9 input port 10 and 12 1st output port groove 11 and 13 2nd output port groove 15 1st link passage 16 2nd link passage 17 2nd relay port groove 18 1st relay port groove 22th 2 cylinder passage 24 1st cylinder passage 25, 26 connecting groove 33 2nd communicating passage 34 1st communicating passage PC power cylinder 23a 1st cylinder chamber 23b 2nd cylinder chamber

Claims (1)

[Claims] 1. A power steering system comprising a sleeve around a rotary pool associated with a steering wheel, wherein the relative positions of the rotary pool and the sleeve are changed according to the turning of the steering wheel to control the fluid introduced to the power cylinder. A pair of inlet ports located on the diameter line of the sleeve and connected to the pump; a pair of first output port grooves that are located on one side of the pair of inlet ports and are opposed to each other; A pair of second output port grooves that are located on the other side of the pair of inlet ports and that face each other, and first and second relay ports that are located approximately 90 degrees apart from the inlet port and that face each other; First passage grooves located on both sides of the first relay port,
A second passage groove is formed on both sides of the second relay port, and the rotary pool continuously communicates with the pair of inlet ports. When the steering wheel is neutral, the inlet port communicates with the output port grooves on both sides of the inlet port. And a pair of return grooves that are located on both sides of each of the pair of linking grooves and that communicate with the output ports when the handle is neutral and return the fluid to the tank.
A first communication groove that communicates the relay port with the first passage grooves on both sides thereof, and a second communication groove that communicates the second relay port with the second passage grooves on both sides thereof when the handle is in neutral, and The first connecting passage connecting the first relay port to the pair of first output port grooves, the second connecting passage connecting the second relay port to the pair of second output port grooves, and the first passage groove of the power cylinder. A first cylinder passage connecting to the first cylinder chamber and a second cylinder passage connecting the second passage groove to the second cylinder chamber of the power cylinder are provided, and the steering wheel is steered to change the relative position of the rotary pool and the sleeve. When it changes,
Depending on this relative position, the first output port groove or the second output port groove
The opening between one of the output port grooves and the inlet port is increased, and the opening between the other output port groove and the return groove is increased, so that the pump discharge fluid is either in the first communication passage or the second communication passage. While being guided to one side, the fluid in the other communication path is guided to the return path, and further, the first relay port, the first passage groove, and the first communication groove are formed in combination in accordance with the turning of the handle. A power steering device characterized in that the opening of the first cylinder throttle and the second cylinder throttle, which is also formed by combining the second relay port, the second passage groove, and the second communication groove, are large.