JPH0122965Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a drive circuit device that drives a working machine such as a construction machine.

In the conventional system, as shown in FIG. 1, a single pump a supplies power to actuators e, f, and g through valves b, c, and d, thereby driving each working machine.

FIG. 1 shows the case in which valves b, c, and d are all in a neutral state, and FIG. 2 shows a state in which valves c and d are in the operating position.

In FIG. 2, when valves c and d are both operated, oil is supplied from pump a to actuator f through valve c, and actuator f is operated. However, since oil from pump a is not supplied to valve d, actuator g is
Therefore, the operator cannot operate valves c and d at the same time, and when setting valve c to the operating position, valve d must be placed in the neutral position, making the operation difficult.

The present invention was developed in view of the above circumstances, and its purpose is to operate each work machine cylinder without being affected by external force even if two valves are simultaneously operated to the operating position. The purpose of the present invention is to provide a drive circuit device for a work machine that can be used.

Hereinafter, the present invention will be explained with reference to FIG. 3 and subsequent figures.

In the drawing, 1 and 2 are first and second pumps, 3 is a blade control valve, 4 is a tilt control valve, 5a is a control valve, 6 is an unload valve, 17a is a main valve, and 55 is a shuttle. It is a valve. The control valve 3 and the unload valve 6 constitute a proportional control valve A with pressure compensation.

The control valve 5a includes a valve body 91, and the valve body 91 has a spool hole 92a.
is provided in the valve body 91, and a spool hole 9 is provided in the valve body 91.
Rooms 23, 30, 75, 77a, 5 leading to 2a
3, 22, 24, 28, and Ba are provided. A spool 19a is fitted into the spool hole 92a, and spring seats 94, 95 are provided at the ends of the spool 19a.
are provided in contact with the respective shoulders, and a spring 96 is provided between both spring seats 94 and 95. Said room 2
2 and 24 communicate with the chamber 28 via a passage 97, and a check valve 27 is provided in the passage 97.

and passage 97, check valve 27, chamber 77a,
The chamber 75, the chamber 28, and the chamber 30 form an operating pressure circuit section E, and the passage 97, the chamber 23, the chamber 24, and the chamber 53 form a pilot pressure circuit section F.

The main valve 17a includes a valve body 17, and the valve body 17 has spool holes 99, 10.
0,101 is provided.

The valve body 17 has a chamber 4 communicating with the spool hole 99.
Further, the valve body 17 is provided with chambers 32, 35 communicating with the spool hole 100, and the valve body 17 is provided with chambers 50, 73 communicating with the spool hole 101.

A spool 18 is fitted into the spool hole 99, and the spool 18 is held neutrally by springs 48 and 48' at both ends thereof. 4
7, and these form the third valve part I.

A spool 33 is fitted into the spool hole 100, and is held neutrally by a spring 38. Perforated holes 37 and 42 are formed in the spool 33, and these form a first valve portion G.

A spool 71 is inserted into the spool hole 101, and this spool 71 is held neutrally by a spring 38'.The spool 71 is also formed with drilled holes 79 and 91, which allow the second
A valve portion H is formed.

The case 98 includes a shuttle valve 40 and a case 98a.
A shuttle valve 45 is provided.

Port 40a of shuttle valve 40 communicates with chamber 102 via passage 39, port 40b of shuttle valve 40 communicates with chamber 80 via passage 90, and port 40c communicates with chamber 102 via passage 90'.
It leads to 1.

Port 45a of shuttle valve 45 communicates with chamber 103 via passage 92, another port 45b communicates with chamber 43 via passage 44, and yet another port 45c communicates with chamber 47 via passage 46. I understand. Passage 104 from chamber 65a to chamber 49
A check valve 66 is provided at the top.

The shuttle valve 55 includes a valve body 7,
A spool hole 110 is provided in the valve body 7, and a plug 57 is fitted into the end of the spool hole 110. A spool 12 is provided in the spool hole 110, and a piston 56 is fitted into the end of the spool 12. The spool 12 is urged toward the plug 57 by a spring 58. The valve body 7 is provided with chambers 9, 59, 60 communicating with the spool hole 110.

5 in the drawing is another control valve, 17'a
is the other main valve.

The other control valve 5 has the same structure as the one control valve 5a except for the chamber Ba and the annular groove C of the spool 19a, and its part number is indicated by (').

The other main valve 17'a has the same structure as the one main valve 17a, and its part number is indicated by (').

The discharge side of the first pump 1 is connected to the chamber 65a of the main valve 17a via a pipe 64, and the discharge side of the first pump 1 is connected to the port 6a of the unload valve 6 via a branch point 63. There is. The chamber 51 of the main valve 17a communicates with the tank 111 via a pipe 70. The chambers 35, 50 of the main valve 17a are connected to the lifter tilt cylinder 16a, which is the working machine cylinder B, via pipes 36, 68. In addition, the chamber 3 of the main valve 17a
2 and 73 are connected to the chambers 30 and 75 of the control valve 5a via pipes 31 and 74. Second
The discharge side of the pump 2 is connected to a passage 97 of a control valve 5a via a pipe 20a, and a control valve 4 of a tilt cylinder 112, which is another working machine cylinder E, is provided in this pipe 20a. The chamber 23 of the control valve 5a is connected to the pipe 2
Passage 9 of the other control valve 5 via 1a
It is connected to 7'. Further, the chamber 23' of the other control valve 5 is connected to the port 3a of the control valve 3 via pipes 21 and 15. The control valve 3 operates the blade cylinder 113, which is another working machine cylinder D. The chamber 77a of the control valve 5a is the pipe 7
It is connected to tank 111 via 8. The chamber 23' of the other control valve 5 is connected to the port 6b of the unload valve 6 via a pipe 21.

The chamber 53 of the control valve 5a is connected to the port 5 of the shuttle valve 59' via a pilot line 54a.
9a, the outlet port 59b of the shuttle valve 59' is connected to the chamber 59 of the shuttle valve 55 via the pilot line 54b, and the chamber 60 of the shuttle valve 55 is connected to the chamber 59 of the shuttle valve 55 via the pilot line 62. It is connected to the pilot port 6d of the load valve 6.

A throttle 11 is provided in this pilot conduit 62. A pilot line 115 branches off from the pipe 15, and this pilot line 115 is connected to the pilot port 6e of the unload valve 6.

The chamber 9 of the shuttle valve 55 is connected to the shuttle valve 10 via a pilot line 13.

The discharge side of the first pump 1 is connected via a conduit 62' to a chamber 65' of the other main valve 17'a. The chamber Ba of one control valve 5a is connected to the chamber 7 of the other control valve 5 via a conduit 78.
It is connected to 7'.

Another inlet port 59c of the shuttle valve 59'
is connected via a pilot line 54 to a chamber 53' of another control valve 5.

The chambers 35', 50' of the other main valve 17'a are connected to the lifter tilt cylinder 16', which is the working machine cylinder B', via pipes 36', 68'.
Further, the chambers 32', 73' of the main valve 17'a are connected to the chambers 30', 75' of the other control valve 5 via pipes 31', 74'.

Shuttle valve 59' transfers the pressure in chamber 53 or chamber 53', whichever is higher, to port 59 of shuttle valve 55.
It is now being introduced to

Next, the operation will be explained.

While the engine is rotating, when the control valves 3, 4, and 5a are in the neutral state as shown in FIG. The spring side pressure at the right end of the unload valve 6 is connected to the chamber 9 through the throttle 11 and the groove 8 cut out in the spool 12 of the shuttle valve 55, and is connected to the drain passage from the shuttle valve 10 through the control valve 3 through the pilot pipe 13. 1
Since the unload valve 6 is connected to the tank 111 through 4, the unload valve 6 is in the state shown in FIG.
The first pump 1 is in an unloaded state at low pressure. On the other hand, the discharge side of the second pump 2 is connected to the unload valve 6 by the piping 21 through the control valves 4, 5a, 5, but the unload valve 6 is in the state shown in FIG. is also in an unloaded state at low pressure.

Note that when the control valve 3 and the control valve 5a are operated simultaneously, the control valve 3 is given priority. Therefore, the spool 12 of the shuttle valve 55 is pressed against the plug 57, and the unload valve 6 assumes a position where oil from the first and second pumps 1 and 2 can be supplied to the control valve 3. However, in this case, the relationship between the control valve 3 and the main valve 17a is a parallel circuit, so the pump oil flows to the side with the lighter load. In the circuit shown in FIG. 3, it is practically rare to operate the control valves 3 and 5a simultaneously, and no particular consideration is given to flow rate distribution in that case.

In the shuttle valve 55, the spool 12 and the piston 56 are provided with a difference in area in order to give priority to the circuit of the control valve 3 as described above.

When the spool 19a of the control valve 5a is operated to the pulled state, the flow of the second pump 2, which has been flowing from the pipe 20a, from the chambers 22, 24 of the control valve 5a, through the constrictions 25, 26 of the spool 19a, is brought into a closed state. At the same time, the check valve 27 is forced open and the flow passes from the chamber 28 around the constriction 29 of the spool 19a and into the chamber 30. It flows from the chamber 30 through the conduit 31, from the chamber 32 of the control valve 17a, through the notch 34 of the spool 33 and into the chamber 35, and at the same time flows into the bottom side of the lipper tilt cylinder 16a through the conduit 36. The pressure on the high pressure side before passing through the spool 33 is guided from a drilled hole 37 in the spool 33 through a chamber 102 of the spool 33 to a passage 39 and a shuttle valve 40 to a chamber 41 which is a pressure chamber at one end of the spool 18 of the main valve 17a. It will be destroyed.
On the other hand, the pressure on the low pressure side after passing through the notch 34 of the spool 33 is guided to a chamber 43 at one end of the spool 33 through a drilled hole 42 in the spool 33, and is guided to a chamber 43 at one end of the spool 33,
4. It is guided through a shuttle valve 45 and a passage 46 to a chamber 47 which is a pressure chamber at the other end of the spool 18. As a result, the spool 18 has chambers 41 and 4 which are pressure chambers.
7 until the differential pressure of the main valve 17a and the spring 48 in the chamber 47 are balanced, and the chamber 49 and the chamber 35 of the main valve 17a
Change communication from closed to open.

Further, the relationship between the chamber 50 connected to the rod side of the lipper tilt cylinder 16a and the chamber 51 which is the tank port of the main valve 17a is changed from the closed state to the open state.

On the other hand, in response to a pull signal from the control valve 5a, the gap between the chambers 24 and 53 is changed from closed to open by the notched groove 52 cut out in the spool 19a, and the pump pressure is controlled by the pilot pipe 54a to the shuttle valve 5.
This acts on the piston 56 provided in the spool 12 of No. 5, which is held down by the plug 57, so the spool 12 moves to the left against the spring 58, opening the chambers 60 and 9. The notch 8 is closed, and the chambers 59 and 60 are connected to the constriction 6 of the spool 12.
1, it becomes open, and the pilot pipe 62 and the orifice 1 are opened.
1 to the spring chamber side of the unload valve 6. As a result, the pressure of the second pump 2 causes the fourth
Unload valve 6 in the unload state shown in the figure
will be forced into an on-load state as shown in Figure 5,
The first pump 1 also becomes high pressure and connects the pipe 6 from the branch point 63.
4 to open the check valve 66 from the chamber 65a which is the pump port of the main valve 17a.
9. The flow passes through the constriction 67 of the spool 18 in the open state, merges with the flow rate of the second pump 2 in the chamber 35, flows to the cylinder bottom side, extends the lipper tilt cylinder 16a, and returns the flow rate from the cylinder rod side to the pipe 6.
8 to chamber 50, through the constriction 69 of spool 18 in the open state, and from chamber 51, which is a tank port, through piping 70 and back to tank 111.

Similarly, the spool 19 of the control valve 5a
Ritupa tilt cylinder 1 also when a is set to the push position.
6a can be driven to the contraction side.

Also, the spool 1 of the other control valve 5
When 9' is pulled, the pipes 20a and 21a
The flow of the second pump 2, which had been flowing from the chambers 22', 24' of the control valve 5 through the constrictions 25', 26' of the spool 19', becomes closed.
At the same time, the flow pushes open the check valve 27',
The chamber 28' leads to the chamber 30' around the constriction 29' of the spool 19'. Control valve 17'a is connected to chamber 3 from chamber 30' through conduit 31'.
2' through the notch 34' of the spool 33' and into the chamber 35' via the conduit 36' to the bottom side of the ripper lift cylinder 16'. The pressure on the high pressure side is passed through the chamber 102' of the spool 33' through the through hole 37' drilled in the spool 33', the passage 39', the shuttle valve 40', and the pressure chamber at one end of the spool 18' of the main valve 17'a. They are led to a certain room 41'.
On the other hand, the pressure on the low pressure side after passing through the notch 34' of the spool 33' is
2' to a chamber 43' at one end of the spool 33',
It is guided through a passage 44', a shuttle valve 45', and a passage 46' to a chamber 47' which is a pressure chamber at the other end of the spool 18'. As a result, the spool 18' is affected by the differential pressure between the pressure chambers 41' and 47' and the spring 4 in the chamber 47'.
8' until it is balanced with main valve 1.
The communication between the chamber 49' and the chamber 35' of 7'a is changed from the closed state to the open state.

Further, the relationship between the chamber 50' connected to the rod side of the lipper lift cylinder 16' and the chamber 51' which is the tank port of the main valve 17'a is changed from the closed state to the open state.

On the other hand, when the control valve 5 is pulled, a notched groove 52' in the spool 19' opens the chamber 2
4' and the chamber 53' from closed to open, and the pump pressure is controlled by the shuttle valve 55 through the pilot line 54.
acts on the piston 56 provided in the spool 12, which is held down by a plug 57,
The spool 12 moves to the left against the spring 58,
The notch 8 that opened the chambers 60 and 9 is closed, and the chambers 59 and 60 are opened through the constriction 61 of the spool 12, leading to the spring chamber side of the unload valve 6 through the pilot pipe 62 and the throttle 11. It will be destroyed.
As a result, the pressure of the second pump 2 forces the unload valve 6, which was in the unload state shown in FIG. 4, into the on-load state shown in FIG. The flow rate of the second pump 2 is transferred from the chamber 65', which is the pump port of the main valve 17'a, through the chamber 49', which is the pump port of the main valve 17'a, to the chamber 49', which is the pump port of the main valve 17'a, and into the chamber 35' through the constriction 67' of the spool 18' in the open state. The return flow from the cylinder rod side flows from the piping 68' to the chamber 5, extending the ripper lift cylinder 16'.
0', constriction 6 of spool 18' in open state
It returns to tank 111 from chamber 51', which is a tank port, through port 9'.

Similarly, spool 19' of control valve 5
Even when is in the push position, the Ritzpa lift cylinder 1
6' can be driven to the contraction side.

As described above, when the spool 19' of the other control valve 5 is operated, the ripper lift cylinder 16' is activated, and the spool 19' of the other control valve 5 is operated.
When the spool 19a of a is operated, the lifter tilt cylinder 16a is operated. For example, spool 1
When 9' is in the pulled position, the ripper lift cylinder 1
6' operates in the extension direction, and the return oil from the lift cylinder 16' enters the chamber 75' of the other control valve 5, passes through the chamber 77', the chamber Ba of the control valve 5a, and the chamber 77a, and is transferred to the tank 111.
Return to

This state (Ritupa lift cylinder 16' in operation)
At the same time, when the spool 19a of the control valve 5a is operated to the pulled position, the ripper tilt cylinder 16a operates, but since the chamber Ba of the control valve 5a and the chamber 77a are closed by the land portion R, the ripper lift cylinder 16a is operated. Even if an external force in the direction of extension is applied to ', the ripper lift cylinder 16' does not operate and remains fixed, and only the ripper tilt cylinder 16a operates. control valve 5
When the spool 19a of a is operated to the N (neutral) position, the ripper lift cylinder 16' also starts operating. Therefore, even if the spool 19' and the spool 19a are simultaneously operated to the operation position (pull or push), each cylinder can be operated without being affected by external force.

As detailed above, the present invention has a first pump 1.
, a second pump 2, a valve body 91' having an operating pressure circuit section E' and a pilot pressure circuit section F'.
By operating the spool 19' provided at 1', the oil discharged from the second pump 2 is taken out as working pressure through the working pressure circuit section E', and the oil discharged from the second pump 2 is taken out as working pressure through the pilot pressure circuit section F'. control valve 5, which is extracted as pilot pressure, and valve body 1.
7' has a first valve part G', a second valve part H', and a third valve part I', and the first valve part G' (second valve part H') is operated by the operating pressure from the control valve 5.
Due to the switching operation of spool 1 of the third valve part I'
8', the pressure oil from the first pump 1 and the second
The confluence of pressure oil from pump 2 is transferred to the work equipment cylinder.
Main valve 1 that supplies oil to B' and drains return oil from work machine cylinder B' to tank 111
7'a, the valve body 17' has a first valve part G, a second valve part H, and a third valve part I, and the first valve part G is operated by the operating pressure from the control valve 5a.
(The switching operation of the second valve part H) operates the spool 18 of the third valve part H, and supplies the combined amount of pressure oil from the first pump 1 and pressure oil from the second pump 2 to the work machine cylinder B. At the same time, the main valve 17a drains the return oil from the working machine cylinder B into the tank 111, and the valve body 91 has an operating pressure circuit section E and a pilot pressure circuit section F, and the spool 19a provided in the valve body 91 operates. The discharge oil of the second pump 2 is taken out as the operating pressure of the main valve 17a via the operating pressure circuit section E, and the second pump 2
The discharge oil is taken out as pilot pressure via the pilot pressure circuit section F, and the spool 19a is in the neutral position to guide the return oil of the other main valve 17'a to the tank side, and the spool 19a is in the operating position to lead the return oil to the tank side. This is a drive circuit device for a working machine characterized by comprising a control valve 5a on one side that closes the circuit.

Therefore, if the spool 19a of one control valve 5a is operated at the same time while the other work machine cylinder B is operating, one work machine cylinder B will operate, but the return circuit of the other work machine cylinder B' will be closed. This work machine cylinder
Even if an external force in the direction of extension is applied to B', this work machine cylinder B' does not operate and is fixed, and only one work machine cylinder B operates, and when the spool 19a is operated to the neutral position, the return circuit is opened. The other work machine cylinder B' begins to operate.

For this reason, even if the spools 19a, 19' of both control valves 5a, 5 are simultaneously operated to the operation position, each work machine cylinder B, B' can be operated without being affected by external force.

[Brief explanation of the drawing]

Figs. 1 and 2 are explanatory diagrams of the configuration of a drive circuit device for a conventional work machine, Fig. 3 is an explanatory diagram of the configuration of an embodiment of the present invention, and Figs. 4 and 5 are explanatory diagrams of the operation of the unload valve. It is. 1 is a first pump, 2 is a second pump, 3 and 5 are control valves, 6 is an unload valve, 55
is a shuttle valve.

Claims (1)

[Scope of utility model registration request] The first pump 1, the second pump 2, and the valve body 9
1' has an operating pressure circuit section E' and a pilot pressure circuit section F', and the oil discharged from the second pump 2 is passed through the operating pressure circuit section E' by the operation of a spool 19' provided on the valve body 91'. control valve 5 which extracts the oil discharged from the second pump 2 as operating pressure and extracts it as pilot pressure via the pilot pressure circuit section F'.
The valve body 17' has a first valve part G', a second valve part H', and a third valve part I'.
By switching the valve part H'), the spool 18' of the third valve part I' is operated, and the combined pressure oil from the first pump 1 and the second pump 2 is transferred to the work machine cylinder B'. Supply and work machine cylinder
It has a main valve 17'a that allows the returned oil of B' to flow out into the tank 111, and the valve body 17 has a first valve part G, a second valve part H, and a third valve part I,
The first control valve is operated by the operating pressure from the control valve 5a.
The switching operation of the valve part G (second valve part H) operates the spool 18 of the third valve part H, and the first
The main valve 17a supplies the combined pressure oil from the pump 1 and the pressure oil from the second pump 2 to the work machine cylinder B, and causes the returned oil from the work machine cylinder B to flow out to the tank 111, and the valve body 91 is actuated. It has a pressure circuit part E and a pilot pressure circuit part F, and by operating a spool 19a provided in the valve body 91, the discharge oil of the second pump 2 is taken out as the working pressure of the main valve 17a via the working pressure circuit part E. At the same time, the oil discharged from the second pump 2 is taken out as pilot pressure via the pilot pressure circuit section F, and the spool 19a is in the neutral position and the other main valve 17'
The oil returned from a is guided to the tank side and the spool 19
A drive circuit device for a work machine, comprising: a control valve 5a that closes the return oil circuit at the operating position a.