JP2659097B2 - All hydraulic power steering system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an all-hydraulic power steering device for a vehicle.

(Prior Art) A conventional apparatus of this type will be described below with reference to the apparatus shown in FIG. 1 which is also an embodiment of the present invention.

A steering unit 2 having a switching valve 7 operated by a steering wheel 1, and the steering units 2 and 1
Connected by first hydraulic lines 3 and 4 consisting of a pair of left and right lines,
And a steering cylinder 5 for steering a steered wheel (not shown), and a second hydraulic line 8
And a pump 6 which is a hydraulic pressure source for supplying a hydraulic pressure through the pump.

By the way, in such a device, since the steering wheel 1 and the steered wheels are not mechanically connected but are connected by hydraulic pressure, the steering unit 2,
Due to a hydraulic pressure leak in the steering cylinder 5 or the like, the steering cylinder 5 may be naturally displaced from the neutral position even when the steering wheel 1 is at the neutral position, and the vehicle may meander.

(Problems to be Solved by the Invention) Various correction devices have been proposed for the purpose of correcting such a displacement state so as to maintain a neutral position. If the stroke is insufficient, the correction cannot be performed, and if the correction device breaks down, the steering cylinder 5 operates without permission. In addition to the uncomfortable feeling at the time of the correction, the structure is complicated and expensive. What can be provided simply and inexpensively has various problems such as poor operability.

Therefore, an object of the present invention is to provide a power steering device that solves the above-mentioned problems of the power steering device and can easily correct the target position of the cylinder without largely displacing the position of the steering wheel. To be.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides the conventional steering apparatus, wherein the upstream side of the pressure oil outside the steering unit 2 and the first side in the steering unit 2 are provided.
Third and fourth hydraulic lines 103 and 104 communicating with the second hydraulic line 8 are provided on the upstream side of the hydraulic oil of the hydraulic lines 3 and 4, and the second hydraulic line 8 and the third and fourth hydraulic lines 103 and 104 are provided.
A fifth orifice 95 is provided in the second hydraulic line 8 on the downstream side of the pressure oil from the communication portion with the third and fourth hydraulic lines 103 and 104.
Upstream of the pressure oil outside the steering unit 2 of the first,
The second auxiliary opening / closing valves 105 and 106 are provided, and the seventh and eighth orifices 97 and 98 are provided in the steering unit 2, respectively. The flow rate Q1 of the fifth orifice 95 and the flow rate Q21 of the seventh and eighth orifices 97 and 98 are provided. Q22 is a flow rate Q1> Q21, Q22, the first and second detecting members 101 and 102 for outputting a signal in accordance with the displacement of the handle 1 and the steering cylinder 5 from the neutral position, and these detecting members 101,102
A controller 100 is provided for inputting a signal from the controller and opening and closing the auxiliary opening / closing valves 105 and 106. By operating the handle 1, (1) when the handle 1 is in the neutral position, the fifth, seventh, and eighth The orifices 95, 97, 98 are closed and the first auxiliary on-off valve 105 is opened to communicate the second hydraulic line 8 and the third hydraulic line 103, but the second, third, and fourth hydraulic lines 8, 103, 104
And the communication with the first hydraulic line 3 or 4 is cut off, and the hydraulic oil does not flow through the steering cylinder 5,
(2) During normal steering of the steering wheel 1, the fifth, seventh and eighth orifices 95, 97 and 98 are opened, and the first auxiliary on-off valve is opened.
105 is open and the second and third hydraulic lines 8,103 and the first
The hydraulic lines 3 or 4 communicate with each other, and the hydraulic oil flows through the hydraulic lines 3 and 4 to flow to the steering cylinder 5, and the second auxiliary opening / closing valve 106 is closed so that the communication between the second hydraulic line 8 and the fourth hydraulic line 104 is established. The pressure oil is shut off and the fourth hydraulic line 1
04, and (3) when the stroke of the steering cylinder 5 is insufficient with respect to the rotation amount of the steering wheel 1, the fifth, seventh, and eighth orifices 95, 97, 98
Are opened, the first and second auxiliary opening / closing valves 105 and 106 are opened, the second hydraulic line 8 communicates with the third and fourth hydraulic lines 103 and 104, and the hydraulic pressure is the second hydraulic line 8, the third and fourth hydraulic lines. 103,
104, and flows through the first hydraulic line 3 or 4 to the steering cylinder 5, and (4) when the stroll of the steering cylinder 5 exceeds the rotation amount of the steering wheel 1, the fifth and the seventh , The eighth orifices 95, 97, 98 are opened, and the second hydraulic line 8 and the first hydraulic line 3 or 4 communicate with each other. , The second auxiliary on-off valve 105, 106
Are closed, the second hydraulic line 8 and the third and fourth hydraulic lines
The communication with the third and fourth hydraulic lines 103 and 104 is prevented by interrupting the communication with the third and fourth hydraulic lines 103 and 104.

(Operation) In the above-described structure, when there is no excess or shortage between the amount of rotation of the steering wheel and the stroke of the steering cylinder, the steering is performed by the second hydraulic line and the first auxiliary on-off valve by the controller by the third hydraulic line by opening. When the normal amount of pressure oil is sent to the cylinder and the first and second detecting members detect that the stroke of the steering cylinder is insufficient for the rotation amount of the steering wheel, the controller also opens the second auxiliary on-off valve. Then, when the stroke of the steering cylinder becomes excessive with respect to the rotation amount of the steering wheel, the first and second on-off valves are closed. Pressure oil reduced from that during normal steering to the steering cylinder, Correct the excess or deficiency of the steering cylinder with respect to the dollar rotation amount.

(Embodiment) In the embodiment of the present invention shown in FIG. 1, 1 to 8 are as described above, but 10 is a pressure and flow compensating valve, and a spring 11 is provided in the casing in one direction. The valve 10 is provided with a valve body 12 which is urged by the pump 6. The oil supplied from the pump 6 to the valve 10 is supplied to the valve 10 via an inlet port 34 to be described later via the second hydraulic line 8 from the steering unit 2. It is fed into the unit 2 and on the other hand to the actuator 15 via another line 14.

Return oil from the steering cylinder 5 returns to the tank 16 through an outlet port 35 (described later) of the steering unit 2 via the pipe 17 in the same manner as return oil from the actuator 15.

Pilot port described later on steering unit 2
40 is a pressure and flow compensation valve via the pilot hydraulic line 18
The orifices 19 and 20 are provided in the middle of the hydraulic line 18, and a line 21 communicating with the line 17 is provided on the spring 11 side of the hydraulic line 18. twenty one
Is provided with a relief valve 22.

Second and third details of one example of the steering unit 2 are shown.

Reference numeral 31 denotes a housing. A spacer plate 32, an amplifying section 33, and an end cap 28 are sequentially arranged at the right end of the housing 31, and these are connected to the housing 31 by bolts 29.

The housing 31 has a radial inlet port 34, an outlet port 35, first and second auxiliary inlet ports 38, 39, a pilot port 40, a right port 43, and a left port 44. The central hole 36 has ports 35, 35. , 43, 44 are formed with annular grooves 41, 42, 45, 50.

A switching valve 7 is rotatably disposed in the center hole 36. The switching valve 7 includes a rotatable spool 47 and a sleeve 48 cooperating therewith. 37 are integrally connected.

Reference numeral 49 denotes a spool 47 and a sleeve 48 as shown in FIG.
A centering spring with both ends fitted in through holes provided in
As shown in FIG.
After being movably penetrated in the circumferential direction, the stopper pin 53 supported by the through hole of the sleeve 48 and the drive shaft 53 are respectively shown.
A fork is provided at one end of the drive shaft 53, through which a stopper pin 51 penetrates, and a head 54 with splines is provided at the other end. The amplifying section 33 meshes with the internal teeth member 55 and the internal teeth of the internal teeth member 55, has one less tooth than the internal teeth member 55, and is provided eccentrically inside the internal teeth member 55 to perform rotation and revolution. A spline 57 is provided in the center hole of the external tooth member 56, and the spline of the head 54 of the drive shaft 53 is engaged with the spline 57.

As shown in FIGS. 3 and 6, the sleeve 48 has an annular groove 65 communicating with the annular groove 41 of the housing 31, through holes 59, 60, 61 communicating with the annular grooves 42, 45, 50, and a port 38, respectively. Annular grooves 62, 63, 64 communicating with 39, 40 are provided. More sleeve
48, the annular groove 4 of the housing 31 as shown in FIG.
Through holes 60, 61 communicating with 5, 50, through holes 68, 69, 58 respectively communicating with the annular grooves 62, 63, 65, oblique through holes 67 communicating with the annular groove 64,
A radial through hole 71 arranged between the annular grooves 62 and 64 and a through hole 72 arranged in the same direction and to the right of the annular groove 65 are provided.

As shown in FIG. 7, the spool 47 has an axial groove 75 partially communicating with the through hole 52, an axial groove 76 alternately arranged with the groove 75, and circumferentially communicating the groove 76. Annular groove 77,
An axial groove 78 extending from the annular groove 77 in a direction opposite to the groove 76,
A narrow groove 79 and an axial groove extending in the same direction from the tip of this groove 78
An axial groove 80 alternately arranged with 78, an annular groove 81 communicating the groove 80 in the circumferential direction, and an axial groove 80 extending from the annular groove 81.
An axial groove 82 extending in a direction opposite to that of the axial groove 82, and an axial groove 83 extending to the edge in the middle of the axial groove 82 are provided.

Again with respect to the housing 31, an axial hole 86 communicating with the through hole 71 of the sleeve 48, and a hole 87 extending in the axial direction from the end toward the amplification section 33 are provided.
Are communicated with the pressure chamber 89 of the amplifier 33.

By the relative rotation of the spool 47 and the sleeve 48 during operation in the above-described apparatus, the following orifices are formed by the respective parts thereof, which will be described with reference to FIGS.

It is the through hole 72 of the sleeve 48 and the axial groove 8 of the spool 47.
2, 83, a second orifice 92 between the through hole 58 of the sleeve 48 and the axial groove 80 of the spool 47, a through hole 71 of the sleeve 48 and the axial groove 80 of the spool 47. The fourth orifice 94 between the third orifice 93 and the through hole 71 of the sleeve 48 and the axial groove 78 of the spool 47, and the through hole of the sleeve 48
Fifth orifice 9 between 60 and axial groove 76 of spool 47
The sixth orifice 96 between the through hole 61 of the sleeve 48 and the axial groove 75 of the spool 47, the through hole 68 of the sleeve 48 and the spool
The seventh orifice 97 between the 47 axial grooves 79 and the sleeve 48
An eighth orifice 98 is formed between the through hole 69 and the axial groove 79 of the spool 47.

In addition to the above, in the present invention the first
As shown in the figure, there is a controller 100, which includes a second detecting member 10 comprising a stroke sensor of the cylinder 5.
2, the second hydraulic line 8 and the first and second auxiliary inlet ports 38, 39
The first and second auxiliary on-off valves 105, 10 each composed of a solenoid valve provided in third and fourth hydraulic lines 103, 104 for communicating
6, and a first detection member 101 formed of a rotation angle sensor of the handle 1 provided opposite to the input shaft 37 are connected to each other.

 The operation of the above will be described.

(1) When the steering wheel is neutral (FIG. 1) The oil that has flowed into the steering unit 2 from the pilot port 40 of the housing 31 through the pilot hydraulic line 18 via the pressure flow compensating valve 10 into the annular groove 64 of the sleeve 48 and the oblique through hole Through 67, the axial groove 80 of the spool 47, the annular groove 81,
It flows into the axial groove 82, further enters the through hole 72 of the sleeve 48, again enters the inside of the spool 47 from the axial groove 83 of the spool 47, and flows from the outlet port 35 to the tank 16.

In this case, the flow rate is determined by the orifice 19 of the pressure flow rate compensating valve 10.
And the pressure B of the spring 11, the orifice 1
9. Due to the relationship with the pressure B, the flow rate becomes small, and as a result, most of the oil discharged from the pump 6 flows through the pipe 14 to the actuator 15.

At this time, the first auxiliary opening / closing valve 105 is open, but since the switching valve 7 is in the neutral position and is blocked as in the conventional one, oil supply to the steering unit 2 is prevented. .

(2) Steering When the steering wheel 1 is turned, the centering spring 49 inside the steering unit 2 bends, and the sleeve 48 and the spool
An angular displacement occurs between 47 and each orifice opens. Also, the axial grooves 82, 8 of the spool 47 that were open when the handle was neutral
First orifice 91 composed of 3 and through hole 72 of sleeve 48
Is closed.

(I) During normal steering (FIGS. 8 and 11A) Oil flowing into the steering unit 2 from the inlet port 34 of the housing 31 through the second hydraulic line 8 from the pressure flow compensating valve 10 is supplied to the housing 31 The annular groove 41, the annular groove 65 of the sleeve 48, the through hole 58 of the sleeve 48, and the axial groove of the spool 47.
80 and the second orifice 92 formed through the through hole of the sleeve 48
It flows through the third orifice 93 formed by the axial groove 78 of the spool 47 into the holes 86 and 87 of the housing 31, passes through the through hole 88 of the spacer plate 32, and passes through the external tooth member 56 of the amplifier 33. Is rotated to measure the amount of discharged oil, and then the hole 86 of the housing 31 is again
The fourth orifice 94 formed by the through hole 71 of the sleeve 48 and the axial groove 78 of the spool 47, and the axial groove 7 of the spool 47
8, through the annular groove 77, the axial groove 76, the through hole 6 of the sleeve 48
Through the fifth orifice 95 formed by the axial groove 76 of the spool 47 and the annular groove 45 of the housing 31 and the annular groove 45 of the housing 31, the fluid flows from the right port 43 to the cylinder 5, and the flow rate is the same as that of the conventional device.
Q1 + q.

In this case as well, when the steering wheel is neutral, the first auxiliary opening / closing valve 105 is opened, and the oil flowing there flows through the third hydraulic line 103 to the first auxiliary inlet port 38 of the steering unit 2. Then, the oil flows into the annular groove 62 of the sleeve 48, passes through the seventh orifice 97 formed by the through hole 68 of the sleeve 48 and the axial groove 79 of the spool 47, and from the fifth orifice 95 to the cylinder similarly to the oil described above. Flow rate to 5 Q21
And the flow rate into the cylinder 5 is Q1
+ Q21 + q.

In this state, the rotation amount of the handle 1 and the cylinder 5
The corresponding value for the stroke is determined as a target set value as shown in FIG.

Then, the return oil from the cylinder 5 flows into the steering unit 2 from the left port 44 of the housing 31 in the same manner as in the conventional case, and is returned from the annular groove 50 of the housing 31 to the sleeve 48.
And flows through the sixth orifice 96 formed by the through hole 61 of the spool 57 and the axial groove 75 of the spool 57, passes through the inside of the spool 47, and returns to the tank 16 from the outlet port 35.

(Ii) When the stroke of the cylinder 5 is insufficient with respect to the rotation amount of the handle 1 (FIGS. 9 and 11 (B)). In this case, as shown in FIG. 1
Since the stroke of the cylinder 5 is insufficient for the amount of rotation, the second auxiliary opening / closing valve 106 is opened by the controller 100, and the oil flowing therethrough passes through the fourth hydraulic line 104 to the steering unit 2. Flows into the second auxiliary inlet port 39 of FIG. An eighth orifice 98 formed by the through hole 69 of the sleeve 48 and the axial groove 79 of the spool 47
, The excess oil flows to the cylinder 5 by a flow rate Q22 more than usual to correct the shortage. Therefore, the inflow flow rate at this time is Q ₁ + Q ₂₁ + Q ₂₂ + q.

(Iii) When the stroke of the cylinder 5 exceeds the rotation of the handle 1 (FIGS. 10 and 11 (C)). In this case, as shown in FIG.
Since the stroke of the cylinder 5 exceeds the rotation amount of the controller 5, it is necessary to correct the stroke.
0, both auxiliary on-off valves 105 and 106 are closed, oil supply to both auxiliary inlet ports 38 and 39 is stopped, and the cylinder 5
The flow rate Q21 is subtracted from the flow rate Q1 + Q21 + q (FIG. 9) of the oil flowing into the cylinder 5, and the reduced flow rate oil Q1 + q flows into the cylinder 5 to correct the excess.

Although the above description has been made on the case where the handle 1 is rotated rightward, the description thereof will be omitted when rotating the handle 1 leftward since the direction is just opposite to the above.

In this embodiment, the flow rates Q21 and Q22 of the correction oil are not affected by the load pressure of the cylinder 5 or the like.
Since it is determined by the area of each orifice that changes according to the angular displacement between the spool 47 and the sleeve 48 accompanying the rotation of the handle 1, a constant proportion of correction oil can always be secured, and therefore, By changing the area, the flow rate of the correction oil can be changed, and an appropriate amount of oil can be easily secured.

Further, since there is no difference between the pressure of the cylinder 5 and the pressures of the third and fourth hydraulic lines 103 and 104 for correction at the time of correction, an uncomfortable feeling such as a shock of the vehicle body is not given to the operator.

Even if a failure occurs in the controller 100 and the auxiliary opening / closing valves 105 and 106, the steering can be performed without much difference from the normal state because the flow rates Q21 and Q22 of the correction oil are small.

The above-described embodiment is not limited to this, and it is needless to say that the deformation thereof is possible, and an example of the deformation is caused by a leak in the steering unit 2 at the stroke end. The rotation of the steering wheel 1 causes the first detection member 101
A stopper for limiting the number of rotations of the handle 1 is provided at a necessary position so that the detection area does not deviate.
5, 106 are provided separately from the steering unit 2, but may be formed integrally therewith.

Note that a circuit is set in the controller 101 so that both the solenoid valves 105 and 106 can be turned on or off, that is, open or closed at the same time. When the two solenoid valves 105 and 106 are turned off (FIG. 10), the stroke of the cylinder 5 becomes smaller with respect to the rotation of the steering wheel 1, so that the straight running performance is improved, and therefore, it is possible to perform a delicate steering operation in a narrow place. Become. On the other hand, when both solenoid valves 105 and 106 are turned on (FIG. 9), the cylinder 5
, The working efficiency can be improved by speeding up the switching of the handle 1.

(Effects of the Invention) The present invention is as described above. In the conventional steering apparatus, the third and fourth communication units connect the second hydraulic line and the steering unit and have the first and second auxiliary opening / closing valves, respectively. Hydraulic lines, first and second detection members that output signals in accordance with displacements from a neutral position of a steering wheel and a steering cylinder, and a controller that inputs signals from these detection members to open and close the auxiliary on-off valves When the cylinder stroke with respect to the rotation amount of the handle is excessive or insufficient, the controller controls the opening and closing of the first and second auxiliary opening / closing valves by a signal from the first and second detecting members. To correct the excess and deficiency. At that time, when the steering is normal, Q1 + Q21 amount of hydraulic oil is used, and when the cylinder stroke is insufficient, Q1 + Q21 + Q22 amount of hydraulic oil is used. When the stroke is over, Q1 pressure oil is supplied to the steering cylinder. Therefore, even if a failure occurs in the first and second auxiliary opening / closing valves, Q1 pressure oil is supplied from the second hydraulic line to the steering cylinder. Since the quantity Q1 is Q1> Q21, Q22, the oil is always sent to the steering cylinder during steering, so that the steering wheel does not run idle and the steering cylinder does not operate irregularly. The shift can be easily corrected by an appropriate steering operation, and in addition, there is an effect that a dangerous state does not occur due to an operation of the steering cylinder without permission.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram when the embodiment of the present invention is in a neutral state, FIG. 2 is a vertical front view of a representative example of the same steering unit, and FIG. 3 is surrounded by a line 3 in FIG. FIG. 4 is an enlarged view of a portion, FIGS. 4 and 5 are longitudinal sectional side views of a part of the same, FIG. 6 is a surface development view of the sleeve of FIG. 2, and FIG. 7 is a spool of FIG. Surface development of the
FIG. 8 is a hydraulic circuit diagram during normal steering of the embodiment, FIG. 9 is a hydraulic circuit diagram when the stroke of the cylinder is insufficient with respect to the rotation amount of the steering wheel,
FIG. 10 is a hydraulic circuit diagram when the stroke of the cylinder is larger than the rotation amount of the steering wheel, and FIGS. 11 (A), (B) and (C) are FIGS. 8, 9 and 10. 6 is a graph showing a relationship between a handle rotation amount and a cylinder stroke at a target set value in FIG. DESCRIPTION OF SYMBOLS 1 ... Steering wheel 2 ... Steering unit 3, 4 ... 1st hydraulic line 5 ... Steering cylinder 6 ... Pump, 7 ... Switching valve 8 ... 2nd hydraulic line 18 ... Pilot hydraulic line 31 ... Housing , 33 amplifying section 34 inlet port 35 outlet port 38 first auxiliary inlet port 39 second auxiliary inlet port 40 pilot port 100 controller 101 first detection member 102 second detection member 103 third hydraulic line 104 fourth hydraulic line 105 first auxiliary on-off valve 106 second auxiliary on-off valve

Claims (1)

(57) [Claims] A rotatable housing disposed in a housing;
A steering unit 2 having a switching valve 7 operated by a steering wheel 1 and a steering cylinder 5 connected to the steering unit 2 by first hydraulic lines 3 and 4 composed of a pair of left and right lines and for steering steered wheels; To supply hydraulic oil from the hydraulic power source 6 to the steering unit 2
In the all-hydraulic power steering apparatus including the hydraulic line 8, an upstream side of the hydraulic oil outside the steering unit 2 and an upstream side of the hydraulic oil of the first hydraulic lines 3 and 4 in the steering unit 2. , Second hydraulic line 8
Third and fourth hydraulic lines 103 and 104 communicating with the
A fifth orifice 95 is provided in the second hydraulic line 8 downstream of the pressure oil from a portion where the hydraulic line 8 communicates with the third and fourth hydraulic lines 103 and 104, and the fifth orifice 95 is provided outside the steering unit 2 of the third and fourth hydraulic lines 103 and 104. First and second auxiliary opening / closing valves 105 and 106 are provided on the upstream side of the pressure oil, and seventh and eighth orifices 97 and 98 are provided in the steering unit 2, respectively.
The flow rate Q1 of the fifth orifice 95 and the seventh and eighth orifices
The flow rates Q21 and Q22 of 97 and 98 are flow rates Q1> Q21 and Q22, and the first and second detection members that output signals according to the displacement of the steering wheel 1 and the steering cylinder 5 from the neutral position. 101, 102, and a controller 100 for inputting signals from these detection members 101, 102 and opening and closing the auxiliary opening / closing valves 105, 106 are provided. By operating the handle 1, (1) when the handle 1 is in a neutral state, The fifth, seventh, and eighth orifices 95, 97, and 98 are closed, and the first auxiliary on-off valve 105 is opened to communicate the second hydraulic line 8 and the third hydraulic line 103. Third and fourth hydraulic lines 8,103,104,
The communication with the first hydraulic line 3 or 4 is cut off, and pressure oil does not flow to the steering cylinder 5. (2) When the steering wheel 1 is normally steered, the fifth, seventh, and eighth orifices 95, 97 , 98 open and the first auxiliary on-off valve
105 is open and the second and third hydraulic lines 8,103 and the first
The hydraulic lines 3 or 4 communicate with each other, and the hydraulic oil flows through the hydraulic lines 3 and 4 to flow to the steering cylinder 5, and the second auxiliary opening / closing valve 106 is closed so that the communication between the second hydraulic line 8 and the fourth hydraulic line 104 is established. The pressure oil is shut off and the fourth hydraulic line 1
04, and (3) when the stroke of the steering cylinder 5 is insufficient with respect to the rotation amount of the steering wheel 1, the fifth, seventh, and eighth orifices 95, 97, 98
Are opened, the first and second auxiliary opening / closing valves 105 and 106 are opened, the second hydraulic line 8 communicates with the third and fourth hydraulic lines 103 and 104, and the hydraulic pressure is the second hydraulic line 8, the third and fourth hydraulic lines. 103,
When the stroke of the steering cylinder 5 exceeds the amount of rotation of the steering wheel 5, the fifth and seventh flow lines 104 and the first hydraulic line 3 or 4 flow to the steering cylinder 5. , The eighth orifices 95, 97, 98 are opened, and the second hydraulic line 8 and the first hydraulic line 3 or 4 communicate with each other. , The second auxiliary on-off valve 105, 106
Are closed, the second hydraulic line 8 and the third and fourth hydraulic lines
The all-hydraulic power steering device is characterized in that communication with the third and fourth hydraulic lines 103 and 104 is interrupted and communication between the third and fourth hydraulic lines 103 and 104 is prevented.