JPS6150830B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic system for steering in construction vehicles and the like.

In a conventional device of this type, pressure oil from a hydraulic source is supplied to a steering hydraulic cylinder device that performs steering operation through a single steering valve that is controlled according to the steering direction and its degree. The total amount of pressure oil supplied to the steering hydraulic cylinder device was controlled by the steering valve. Therefore, conventional steering valves are large, and because the steering valve is connected to a steering rod and a feedback rod, the mounting position on the vehicle is greatly restricted, and it is very difficult to install it properly in a narrow space. It was difficult.

To solve this problem, it is conceivable to form the steering valve separately into a pilot valve and a switching valve so that the pilot valve to which the steering rod is connected is made smaller. An example of a conventional example in which the pilot valve and the switching valve are separated is the
There is one mentioned in the publication. However, this is to improve the responsiveness of the cylinder to the rotation of the steering wheel during high-speed steering, but pressure oil is not supplied to the cylinder after the switching valve operates in response to changes in pilot pressure. Since the configuration is
Problems remain in terms of responsiveness to minute movements of the handle. That is, if the switching valve does not operate, the steering operation will not take place, resulting in a delay in turning of the wheels, resulting in poor steering performance. Furthermore, power loss due to the configuration for obtaining pilot pressure cannot be ignored.

SUMMARY OF THE INVENTION An object of the present invention is to provide a steering hydraulic system in which a steering valve coupled to a steering rod can be formed in a small size and has good responsiveness to minute movements of a steering wheel.

The main stage according to the present invention includes a main steering valve connected to the steering rod, and a driven valve that can be installed separately from the main steering valve, for supplying and discharging pressure oil to the steering cylinder device. In addition, the driven valve is not only used as a switching valve that supplies pressure oil from the pressure oil supply source to the steering cylinder device using pilot pressure oil from the main steering valve, but also supplies pilot pressure oil to the cylinder device. This is how it was done. By this,
Even if the driven valve is not yet switched by the slight operation of the handle, pressure oil is supplied from the driven valve to the steering cylinder device, and the steering cylinder device responds.

The present invention will be explained in detail below based on one embodiment shown in the drawings. In the figure, 1 is a steering cylinder device;
2 is a steering main valve, 3 is a steering slave valve, and 4 is a pressure oil supply device.

The steering cylinder device 1 has a conventionally known configuration and is shown schematically. Pressure oil supply and discharge passages 11 and 12 are provided for the cylinder 10, and the piston rod 13 side is connected to the steering steering rod 14 via a connecting rod 15, and the middle of the connecting rod 15 is connected to the steering main valve 2. It is coupled to a driven portion of the main valve body 17.

The steering main valve 2 includes a main body 16, a main valve body 17, and a spring 1.
It consists of 8. A main valve body sliding hole 19 is formed in the main body 16, and two pressure oil sending ports 20, 2 are provided so as to move inside and outside the sliding hole 19.
1, first supply port 22, two discharge ports 23, 24,
A pressure outlet 25 is provided. A main valve body 17 is slidably inserted into the sliding hole 19, and the main valve body 17 has four annular grooves 27, 28,
29 and 30 are formed, and one end of the main valve body 17 is connected to the connecting rod 15. The spring 18 is provided to maintain the main valve body 17 in the neutral state shown in FIG. When the steering rod 14 is in a neutral state, the main valve body 17 is in a neutral state as shown in the figure, and the first supply port 22 communicates with the annular grooves 28 and 29 to the same extent, and the pressure outlet 25 communicates with the annular groove 28 and further connects the main body 1
annular groove 2 through an internal passage 31 provided in 6;
9, and the pressure oil outlet 20 is connected to the annular grooves 27, 28.
Furthermore, the pressure oil outlet 21 communicates with the annular grooves 29 and 30 to a slightly similar extent, the outlet 3 communicates with the annular groove 27, and the outlet 24 communicates with the annular groove 30, respectively. If the steering rod 14 is pulled to the right in the figure, the main valve body 17 moves to the right as shown in FIG. The state of communication with the outlet 25 is increased, and the pressure oil outlet 20 is communicated with the pressure oil outlet 21 via the internal passage 31 and the annular groove 29, and the pressure oil outlet 20 is communicated with the outlet 23 via the annular groove 27. . In this state shown in FIG. 3, the outlet 24 side is closed. Furthermore, if the steering rod 14 is pushed to the left in the figure, the main valve body 17 moves to the left as shown in FIG. 3
1. It communicates with the pressure oil outlet 20 through the annular groove 28, and the pressure oil outlet 21 communicates with the discharge port 24 through the annular groove 30. In this state shown in FIG. 2, the discharge port 23 side is closed.

That is, the state of communication between the first supply port 22 and the annular grooves 28 and 29 of the main valve body 17 is such that communication with one is cut off and communication with the other increases depending on the amount of movement of the main valve body 17. It's becoming like that. Note that the discharge ports 23 and 24 are each connected to an oil storage tank 37.

The steering driven valve 3 includes a main body 38, driven valve bodies 39, 2
The spring 40 is made up of several springs 40. A driven valve body sliding hole 41 is formed in the main body 38, and both ends are sealed with caps 42, 42. Its sliding hole 4
A second supply port 43, which communicates the inside of 1 with the outside.
Two connection ports 44, 45, two discharge ports 46, 4
7, two receiving ports 48, 49 are provided.
A driven valve body 39 is slidably inserted into the sliding hole 41, and the driven valve body 39 has seven holes corresponding to each of the communication ports between the inside of the sliding hole 41 and the outside. annular grooves 50, 51, 52, 53, 54, 5
5 and 56 are provided, internal passages 57 and 58 are provided in the driven valve body 39 along its longitudinal direction, and stepped small diameter portions 5 are provided at both ends of the driven valve body 39.
9 and 60 are formed. The internal passages 57 open at the flow ends of the driven valve bodies 39 and communicate with each of the caps 42, with a throttle 61 provided in the middle, and the middle portions of both sides of the throttle 61 communicate with the annular grooves 50 and 54. The internal passage 58 has both ends a chamber 59 formed in the gap between the inner surface of the sliding hole 41 and the small diameter portions 59 and 60.
a, 60a, and a diaphragm 62 is provided in the middle, and an annular groove 5 is provided halfway on both sides of the diaphragm 62.
2 and 56. A spring 40 is provided within the cap 42 so as to press evenly inwardly on both ends of the driven valve body 39 to maintain the driven valve body 39 in the neutral state shown in FIG. The neutral state of the driven valve body 39 is maintained as long as the pressures of the pressure oil flowing into the receiving ports 48 and 49 are equal. If pressure oil is supplied to the intake port 48 side and the pressure increases, the throttle 6
1, the pressure inside the cap 42 on the left in the figure increases in advance. Further, the pressure oil in the intake port 48 is supplied to the steering cylinder device 1 via the internal passage 57 and the coupling port 45, and the discharge oil from the steering cylinder device 1 is supplied to the steering cylinder device 1 through the coupling port 44, the internal passage 58, the receiving port 49, and the steering cylinder device 1. The oil flows out to the oil storage tank 37 via the main valve 2, but at this time, the pressure in the chamber 59a becomes higher than the pressure in the chamber 60a due to the presence of the throttle 62. left cap 4
When the sum of the acting forces due to the pressure in the chamber 2 and the pressure in the chamber 59a is greater than the sum of the acting forces on the right by a set value or more, the driven valve body 39 moves to the right as seen in FIG. . This movement causes the second supply port 43 to communicate with the coupling port 45 via the annular groove 53, and the coupling port 44 to communicate with the discharge port 46 via the annular groove 51. Further, when the pressure on the intake port 49 side increases, the pressure in the chamber 60a in the gap between the sliding hole 41 and the small diameter portion 60 on the right side in the figure increases first due to the existence of the throttle 62. Further, the pressure oil in the intake port 49 passes through the internal passage 58 and the coupling port 44 to the steering cylinder device 1.
The oil discharged from the steering cylinder device 1 flows through the coupling port 45, internal passage 57, receiving port 48, and main steering valve 2 into the oil storage tank 37, but at this time, due to the presence of the throttle 61, The pressure in the right cap 42 will then be higher than the pressure in the left cap 42.
When the sum of the acting forces due to the pressure in the right cap 42 and the pressure in the chamber 60a becomes greater than the sum of the left acting forces by more than a set value, the driven valve body 39 moves to the left as shown in FIG. Move to. Due to this movement, the second supply port 43 is connected to the coupling port 4 through the annular groove 53.
4, and the coupling port 45 communicates with the discharge port 47 via an annular groove 56. Above intake port 48
is connected to the pressure oil outlet 20 of the main steering valve 2 via the pipe 63
The intake port 49 is connected to the pressure oil outlet 21 of the main steering valve 2 via a pipe 64, and the connection port 44 is connected to one side of the cylinder 10 via the supply/discharge path 12.
is connected to the other cylinder 10 via the supply/discharge path 11, and the discharge ports 46 and 47 are connected to the oil storage tank 37, respectively. The second supply port 43 is connected to a pressure oil supply pipe 65 of the pressure oil supply device 4, which will be described next.

The pressure oil supply device 4 includes a relatively small first hydraulic pump 66 and relatively large second and third hydraulic pumps 6.
7, 68, a pressure oil distribution valve 69, etc.
The pressure oil distribution valve 69 includes a main body 70, a valve body 71, and a spring 72.
It consists of As shown in the figure, a valve body sliding hole 73 with both ends closed is formed in the main body 70, and hydraulic pump connection ports 74, 75 and a first outlet are connected to communicate the inside of the sliding hole 73 with the outside. 76, a second outlet 77 is provided. The first outlet 76 branches into two directions in the middle and opens 76 on the sliding hole 73 side.
a, 76b are formed, and openings 76a, 76b are formed.
Pressure valves 78 and 79 are provided for each of the valves 78 and 79, which can be opened by operating pressure from the internal opening side. The second outlet 77 also branches into two directions in the middle and has openings 77a and 7b.
, and are provided with pressure valves 80 and 81 which are opened by operating pressure from the respective internal opening sides. The valve body 71 is accommodated in the sliding hole 73 with a margin left in the longitudinal direction so as to be able to slide therein, and annular grooves 82, 83, 84, and 85 are formed in the valve body 71. The spring 72 is provided so as to press the left end of the valve body 71 to the right in the figure. A pressure oil introduction port 86 is provided on the end surface of the sliding hole 73 on the side where the spring 72 is located, and a pressure oil introduction port 87 is provided on the other end surface. When the hydraulic pressures acting on both ends of the valve body 71 are equal, the valve body 71 is pushed to the right by the acting force of the spring 72 as shown in FIG. In this state, the connection port 74 is connected to the annular groove 82 and the opening 7
6a, it communicates with the first outlet 76 via the pressure valve 78, and the connection port 75 is connected to the annular groove 84 and the opening 76.
b. It communicates with the first outlet 76 via the pressure valve 79, and the second outlet 77 is closed. In addition, the hydraulic pressure acting on the right end of the valve body 71 is large and the valve body 71
In the state shown in Fig. 1 where the is pressed to the left, the connection port 74
The connection port 75 communicates with the second outlet 77 via the annular groove 83, the opening 77a, and the pressure valve 80, and the connection port 75 communicates with the second outlet 77 via the annular groove 85, the opening 77b, and the pressure valve 81.
It communicates with an outlet 77, and the first outlet 76 is closed. Further, when the valve body 71 is located in the middle of the sliding range as shown in FIG. 2 due to the force acting on both ends of the valve body 71, the connection port 74 communicates with the first outlet 76, and the connection port 74 is connected to the first outlet port 76. Port 75 communicates with second outlet 77 . While the valve body 71 changes from the state shown in FIG. 1 to the state shown in FIG.
All of the pressure oil flowing in from the connection port 75 flows out from the second outlet 77. Furthermore, while the valve body 71 changes from the state shown in FIG. 2 to the state shown in FIG. is the first outlet 7
6 and the second outlet 77 according to the amount of movement of the valve body 71. Connection port 74 of this pressure oil distribution valve 69
A second hydraulic pump 67 is connected to the connection port 75.
A third hydraulic pump 68 is connected to the third hydraulic pump 68, the first outlet 76 is connected to the second supply port 43 of the steering driven valve 3 via the pipe 65, and the second outlet 77 is connected to another working circuit. The pressure oil inlet 86 is connected to the pressure outlet 25 of the main steering valve 2 via a pipe 89, and the pressure oil inlet 87 is connected to the first pressure outlet 25 of the main steering valve 2 via a pipe 90.
It is connected to the supply port 22. First hydraulic pump 6
6 is connected to the first supply port 22 via a conduit 91. In the figure, 92 and 93 are relief valves, 94 is a throttle, and 95 is a check valve that connects the pipe line 91.
It is provided in a conduit 96 connecting the and 65.

In the steering hydraulic system configured as described above, the steering rod 14 is moved by the driver's steering operation, which drives the main valve body 17 of the main steering valve 2 to supply pressure oil. Pressure oil is supplied from the delivery port 20 or 21 to the steering driven valve 3, and the driven valve body 39 is controlled so that the pressure oil supplied from the second supply port 43 and the intake port 48 or 49 is supplied to the steering cylinder device 1. This causes the steering cylinder device 1 to perform a steering operation in accordance with the steering operation. When the main valve body 17 is pushed to the left in the figure, as shown in FIG. The oil is supplied to the intake port 48 of the slave valve 3, and is supplied to the chamber on the left side of the piston of the cylinder 10 via the annular groove 50, the throttle 61, the annular groove 54, and the coupling port 45. , the chamber 59a via the coupling port 44, the annular groove 52, and the passage 58.
At the same time, it is discharged to the oil storage tank 37 via the throttle 62, the discharge port 49, and the main steering valve 2. Therefore, the piston rod 13 moves to the right, and in response to this movement, the main valve body 17 returns to its neutral state. In this manner, the piston rod 1 of the cylinder 10 is moved by an amount corresponding to the amount of movement of the steering rod 14.
3 and operate the steering device connected to this piston rod 13. When the amount of movement of the steering rod 14 is small and the amount of oil supplied to the receiving port 48 is small, the differential pressure across the throttles 61 and 62 is not large and the driven valve body 39 is in the neutral state shown in FIG. When the amount of movement of the steering rod that operates as shown in FIG. The oil discharged from the steering cylinder device 1 is sent to the steering cylinder device 1 via the internal passage 57 and flows to the oil storage tank via the inlet 44, the internal passage 58, and the main steering valve 2, and is then
The differential pressure before and after 2 becomes large, and the left cap 42
When the sum of the acting forces due to the pressure inside and inside the chamber 59a becomes greater than the sum of the acting forces on the right by a set value or more, the driven valve body 39 is moved to the right, and during this time the pressure oil from the second supply port 43 is removed. The piston rod 13 is supplied to the cylinder 10 through the joint port 45 and the pressure oil supply/discharge passage 11.
Move to the right in the diagram. In the main steering valve 2, the main valve body 17 moves to the right due to the movement of the piston rod 13 and returns to the neutral state, and the driven valve body 39 also returns to the neutral state. Moreover, when the main valve body 17 is pulled to the right in the figure, contrary to the above, pressure oil is supplied to the intake port 49 of the steering slave valve 3 via the first supply port 22 and the pressure oil delivery port 21. When the amount of movement of the main valve element 17 is small, the driven valve element 39 does not move, and when the amount of movement of the main valve element 17 is large, the driven valve element 39 is moved to the left, while the second supply port 43, The pressure oil from the receiving ports 48 and 49 is transferred to the connecting port 4.
4. Apply pressure oil to the cylinder 10 via the pressure oil supply/discharge path 12 to move the piston rod 13 to the left in the figure. Therefore, the main valve body 17 also moves to the left and returns to the neutral state, and the driven valve body 39 also returns to the neutral state. In other words, depending on the direction and degree of turning the handle,
The main valve body 17 is driven, and an amount of pressure oil corresponding to the amount of movement of the main valve body 17 is supplied to the steering driven valve 3, and the driven valve body 39 is driven according to the amount of supply, and the driving degree is Pressure oil is supplied to the steering cylinder device 1 in accordance with the above. Therefore, the steering cylinder device is driven according to the direction and degree of rotation of the steering wheel.

Note that the pressure oil supply device 4 mainly supplies pressure oil to the first supply port 22 using the first hydraulic pump 66, and supplies pressure oil to the second supply port 43 from the second and third hydraulic pumps 67 and 68 as necessary. For this purpose, the pressure oil distribution valve 69 is controlled by the valve body 71 according to the pressure difference between the first supply port 22 and the pressure outlet 25, that is, the opening degree of the main steering valve. The required amount is supplied to the driven valve 3. That is, depending on the amount of movement of the main valve body 17 from the neutral state, the greater the amount of movement, the lower the differential pressure between the first supply port 22 and the pressure outlet 25 side, and the valve body 71 moves from the left to the right in the figure. As a result, the pressure oil distribution valve 69 distributes more pressure oil toward the first outlet 76 side.

As mentioned above, according to this steering hydraulic system,
The main steering valve 2 to which the steering rod 14 is attached does not directly control the total flow of pressure oil for steering, but only allows a small amount of pressure oil to flow to the slave valve 3. It can be very small. Further, although a relatively large amount of pressure oil flows through the steering driven valve 3, there are almost no restrictions on the mounting position, direction, etc., as long as a hydraulic pressure line is connected thereto. Therefore, in this steering hydraulic system, the conventional steering valve is appropriately separated into a main steering valve and a slave steering valve, so that installation in a vehicle is limited to a single steering valve. This is significantly reduced compared to conventional equipment using .

Moreover, even if the amount of steering operation by the driver is small, that is, even if the amount of movement of the main valve body 17 is small and the driven valve body 39 is not moving, the amount of power from the main steering valve 2 The steering cylinder device 1 is operated by the supplied pressure oil. Therefore, this steering hydraulic system is
The steering handle responds quickly to minute movements and provides good steering performance. Moreover, since the pressure oil from the steering main valve 2 is supplied to the steering cylinder device 1 via the steering slave valve 3, power loss is small.

Therefore, according to this invention, the design and installation work, which was conventionally extremely difficult, becomes easy and simple.
Moreover, a steering hydraulic system with good responsiveness to minute movements of the steering wheel and with little power loss can be obtained.

[Brief explanation of the drawing]

1 to 3 are schematic partial vertical sectional views showing different states of one embodiment of the present invention. 1... Steering cylinder device, 2... Steering main valve, 3
...Steering driven valve, 4...Pressure oil supply device, 10...
Cylinder, 11, 12... Supply/discharge passage, 13... Piston rod, 14... Steering rod, 15
... Connection rod, 17 ... Main valve body, 19 ... Main valve body sliding hole, 20, 21 ... Pressure oil delivery port, 22 ... First
Supply port, 23, 24... Discharge port, 25... Pressure outlet, 39... Driven valve body, 41... Driven valve body sliding hole, 43... Second supply port, 44, 45... Connection port , 46, 47...Discharge port, 48, 49...Intake port, 66...First hydraulic pump, 67...Second hydraulic pump, 68...Third hydraulic pump, 69...Pressure oil distribution valve.

Claims (1)

[Claims] 1 It has two pressure oil supply and discharge passages, one of which is supplied with pressure oil for steering operation to one side, and the other supply and discharge passage is supplied with pressure oil to perform steering operations opposite to the above. A steering cylinder device configured to perform a steering operation to the side, a first supply port to which pressure oil is supplied, two pressure oil delivery ports, and a steering main valve body, the main valve body of which is configured to perform a steering operation to the side. a rudder that is driven in accordance with the steering direction to move from a neutral position and is configured to switch and send the pressure oil flowing from the supply port to one of the pressure oil delivery ports in accordance with the steering direction; A master valve, two coupling ports connected to the supply and discharge passages of both the steering cylinder devices, a second supply port to which pressure oil is supplied, and a pressure oil delivery port of both the main steering valves. two pressure oil inlets and a driven valve body, each of which is connected via a conduit, the pressure oil inlet is always connected to the connection port separately through each throttle, and the driven valve body is A driven valve driven by the pressure oil supplied to the pressure oil receiving port and controlled to send the pressure oil supplied to the second supply port to one of the two coupling ports in accordance with the steering direction. and,
A steering pressure oil device comprising a pressure oil supply device that supplies a necessary amount of pressure oil to the first supply port and the second supply port.