JPH0341688B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a control circuit for a hydraulic cylinder, and in particular to a control circuit for an outrigger jack cylinder (hereinafter referred to as a jack cylinder) used during disassembly and assembly of a large crawler crane. The present invention relates to a control circuit for a hydraulic cylinder suitable for control.

[Conventional technology]

When large crawler cranes and the like are transported on roads, they are subject to legal restrictions regarding weight, height, and width, so a jack cylinder is used to separate the upper revolving structure, truck frame, and side frame.

Figures 2 and 3 show the disassembly work of a large crawler crane.

As shown in FIG. 2, the four jack cylinders 4a to 4d attached to the upper revolving structure 1 are extended, and then the two rear jack cylinders 4a and 4b are simultaneously extended, and one The side frame 3 is lifted off the ground GL, and further, using an auxiliary crane or the like, the side frame 3 lifted off the ground GL is separated from the truck frame, and then the rear jack cylinders 4a and 4b are reduced in size. Next, the pair of front jack cylinders 4c and 4d are operated to separate the other side frame 3 in the same manner as described above.

Next, as shown in FIG. 3, the truck frame 2 and the upper revolving body 1 are mounted on the trailer 100, and the four jack cylinders 4a to 4d are simultaneously extended to remove the upper revolving body 1 from the truck frame 2.
The upper revolving body 1, truck frame 2, and side frame 3 are transported separately.

Therefore, in the jack cylinders 4a to 4d used for disassembling and assembling large crawler cranes, the set of rear jack cylinders 4a and 4b,
It is necessary to extend and contract the front set of jack cylinders 4c and 4d separately, and the load applied to each jack cylinder 4a to 4d is different, resulting in a difference in the amount of extension and contraction of each jack cylinder 4a to 4d. , in order to correct it, each jack cylinder 4a~
4d must be expanded and contracted individually.

Next, FIG. 4 shows a prior art control circuit for a jack cylinder disclosed in Japanese Patent Application Laid-Open No. 109904/1983.

The control circuit shown in this figure includes a hydraulic pump 5, a main control valve 6, an extension side pipe 7 and a contraction side pipe 8 connected thereto, and the contraction side pipe 8 and the cylinders 4a to 4d. branch pipes 8a to 8d connecting the rod side oil chamber, a first flow divider 9 as a main flow divider connected to the extension side pipe 7, and a set of two jet cylinders 4a. , 4b and 4c, 4d and connected to the first flow divider 9 via conduits 10, 11, respectively. The second and third
the first connected to the flow dividers 12 and 13 of
- fourth control valves 15a to 15b;
These first to fourth control valves 15a to 1
5d and the cylinder head side oil chambers (hereinafter referred to as head side oil chambers) of the relevant cylinders 4a to 4d;
Bypass branch pipes 17a to 1 connected to 16d
7d, a fifth control valve 18 connected to the bypass pipe 17, and an oil tank 19.

The control circuit is then operated as follows.

When extending all the cylinders 4a to 4d at the same time, open the main control valve 6.
is switched to position B, the first to fourth control valves 15a to 15d are switched to position C, which is the operating position, and the fifth control valve 18 is switched to position E, which is the neutral position.

As a result, the pressure oil discharged from the hydraulic pump 5 is transferred from the main control valve 6 to the extension side pipe line 7 to the first flow divider 9 to the pipe line 10.
11 → second and third flow dividers 12,1
3 → Pipes 14a to 14d → First to fourth control valves 15a to 15d → Pipes 16a to 1
The oil is supplied to the head side oil chambers of the jack cylinders 4a to 4d through 6d.

On the other hand, the pressure oil in the rod side oil chambers of the cylinders 4a to 4d is returned to the oil tank 19 through the branch pipes 8a to 8d, the contraction pipe 8, and the main control valve 6.

Therefore, each jack cylinder 4a to 4d
is extended at the same time.

When extending, for example, the jack cylinder 4a individually among the jack cylinders 4a to 4d, the first jack cylinder corresponding to this jack cylinder 4a is extended.
Only the control valve 15a is switched to position C, which is the operating position, and the other second to fourth control valves 15b to 15d are switched to position D, which is the neutral position.

As a result, pressure oil is supplied to the head side oil chamber of the jack cylinder 4a through the same route as when all the jack cylinders 4a to 4d are extended at the same time. . Moreover, the pressure oil that has flowed into the second to fourth control valves 15b to 15d is dropped into the oil tank 19.

Therefore, only the jack cylinder 4a is extended, and the other jack cylinders 4b to 4d are not extended.

When extending the other jack cylinders 4b to 4d individually, the rear jack cylinders 4a and 4
The same operation can be performed when extending the set b or the front set of jack cylinders 4c and 4d individually, or when extending the three jack cylinders at the same time.

When reducing all the cylinders 4a to 4d at the same time, press the main control valve 6.
is switched to the A position, the first to fourth control valves 15a to 15d are switched to the C position, which is the operating position, and the fifth control valve 18 is switched to the E position, which is the neutral position under normal conditions.

Thereby, the pressure oil discharged from the hydraulic pump 5 is supplied to the rod side oil chambers of the cylinders 4a to 4d through the main control valve 6→reduction side pipe 8→branch pipes 8a to 8d.

At this time, the pressure oil in the head side oil chambers of the jack cylinders 4a to 4d flows from the pipes 16a to 16d to the first
~Fourth control valves 15a to 15d→
Pipes 14a to 14d → second and third flow dividers 12, 13 → pipes 10, 11 → first flow divider 9 → extension side pipe 8 → main control valve 6 to oil tank 19 be returned.

Therefore, each jack cylinder 4a to 4d
is reduced at the same time.

A synchronization error occurs during the contraction operation of the jack cylinders 4a to 4d, and the jack cylinders 4a to 4d
If either of them is not reduced to the stroke end, the fifth control valve 18 is switched to the operating position.

As a result, for example, when the jack cylinder 4a does not reach the stroke end, the pressure oil in the head side oil chamber passes through the pipe 16a → bypass branch pipe 17a → bypass pipe 17 → the fifth control valve 18. It escapes to the oil tank 19.

As a result, the jack cylinder 4a whose contraction operation has been delayed also reaches its stroke end. The same applies to the other jack cylinders 4b to 4d.

However, in the conventional control circuit, the jack cylinders 4a to 4d are controlled individually or in sets of two jack cylinders, and preselected sets of two jack cylinders from among a plurality of sets of jack cylinders are controlled simultaneously. It is practically impossible to reduce the size.

That is, for example, when attempting to contract the jack cylinders 4a individually, the main control valve 6 is set to the "A" position, and the jack cylinders 4a are
The first control valve 15a corresponding to a
is switched to the C position, and the other second to fourth control valves 15b to 15d are switched to the D position.

As a result, the pressure oil discharged from the hydraulic pump 5 is transferred from the main control valve 6 to the reduction side pipe 8.
→Flows toward the rod-side oil chamber of the cylinder 4a through the branch pipe 8a.

On the other hand, since the first control valve 15a is switched to position C, the pressure oil in the head side oil chamber of the jack cylinder 4a is
6a → first control valve 15a → pipe line 1
4a → second flow divider 12 → pipe line 10 →
It appears to flow from the first flow divider 9 to the extension pipe 7 to the main control valve 6 to the oil tank 19.

However, the second to fourth control valves 15
b to 15d are switched to the 2 position, and the pipe lines 16b to 16d connected to the head side oil chambers of the jack cylinders 4b to 4d are blocked by the second to fourth control valves 15b to 15d. Therefore, pressure oil does not flow from the pipes 14b to 14d to the second and third flow dividers 12 and 13. As a result, the second flow divider 12 functionally restricts to the maximum extent the branch port to which the pipe line 14a is connected. Therefore, the flow rate of the pressure oil flowing through the head side oil chamber of the jack cylinder 4a → the pipe 16a → the first control valve 15a → the pipe 14a to the second flow divider 12 becomes extremely small, so that the The contraction operation of the jack cylinder 4a becomes extremely slow, and individual contraction operations of the jack cylinder 4a become practically impossible.

The same applies to the other jack cylinders 4b to 4d, and when it is desired to individually reduce the rear set of jack cylinders 4a and 4b, the first flow divider 9 is functionally located on the pressure oil inflow side. Since the diverter port is narrowed down, the above-mentioned jack cylinder 4a~
As with the case where 4d is individually reduced, this is practically impossible.

However, when disassembling and assembling a large crawler crane, the four jack cylinders 4a to 4
The load acting on d tends to become unbalanced,
There is a difference in the amount of extension of the jack cylinders 4a to 4d, and in order to correct this, the jack cylinder 4
There are cases where it is desired to reduce the cylinders a to 4d individually, and there are cases where, for example, it is desired to reduce the rear cylinders 4a and 4b at the same time in order to shorten the working time.

On the other hand, there was a problem that could not be addressed by the conventional control circuit.

[Problem that the invention seeks to solve]

An object of the present invention is to solve the problems of the prior art, and to separate the hydraulic cylinders, which do not include two sets of hydraulic cylinders and are arranged in a plurality of sets, individually or by preselecting two hydraulic cylinders into one cylinder.
An object of the present invention is to provide a control circuit for hydraulic cylinders capable of simultaneously and quickly contracting a set of hydraulic cylinders.

[Means for solving problems]

The present invention is characterized in that a shuttle valve is connected between pipes connecting two control valves provided corresponding to each hydraulic cylinder and one flow divider, and that one outlet of the two shuttle valves is connected to one flow divider. The outlet of the main shuttle valve is connected to the inlets on both sides of the main shuttle valve, and the outlet of the main shuttle valve is connected to an oil tank, and a switching valve is provided between the oil tank and the main shuttle valve. The present invention is characterized in that the switching valve is connected to a pipe line that connects a selected set of two hydraulic cylinders to a flow divider provided for one of the hydraulic cylinders.

[Effect]

In the present invention, when contracting hydraulic cylinders individually, the main control valve is set to the contracting side (position A in Figure 1), and the control valve corresponding to the hydraulic cylinder to be contracted is moved to the operating position (position A in Figure 1). , position C), the other control valves are placed in the neutral position (position 2 in Figure 1), and the switching valve is placed in the first position.
(position G in Figure 1).

As a result, pressure oil is supplied to the rod-side oil chamber of the hydraulic cylinder to be contracted through the main control valve→reduction-side conduit. In addition, the pressure oil in the head side oil chamber of the hydraulic cylinder to be reduced is transferred from the control valve switched to the position C → the pipe connecting the control valve and the flow divider → the shuttle valve →
The oil is dropped into the oil tank through a pipe connecting the shuttle valve and the main shuttle valve -> the main shuttle valve -> the switching valve.

In this way, the pressure oil in the head side oil chamber of the hydraulic cylinder to be reduced does not pass through the flow divider or the main flow divider, but instead flows through the shuttle valve,
Since the oil is dropped into the oil tank through the main shuttle valve and the switching valve, the hydraulic cylinders to be contracted can be individually and quickly contracted, regardless of the throttling action of the flow divider or the main flow divider.

Also, when contracting a set of two preselected hydraulic cylinders at the same time, the main control valve is set to the above-mentioned position A, the control valve corresponding to the hydraulic cylinder to be contracted is set to the above-mentioned position C, and the other control valves are set to the above-mentioned position C. The switching valve is switched to the second position (the H position in FIG. 1).

As a result, pressure oil is supplied from the main control valve to the rod-side oil chamber of the hydraulic cylinder to be reduced through the reduction-side conduit. On the other hand, the pressure oil in the head-side oil chamber of the hydraulic cylinder to be contracted is transferred from the control valve switched to the above position C to the pipe connecting the control valve and the flow divider to the hydraulic cylinder to be contracted. The corresponding flow divider → the pipe connecting this divider and the main flow divider → the pipe connected to this → the flow is dropped into the oil tank through the switching valve.

Therefore, regardless of the throttling action of the main flow divider, the preselected set of two hydraulic cylinders can be contracted at the same operating speed as when all the hydraulic cylinders are contracted at the same time.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, in which a first shuttle valve 21 as a main shuttle valve is installed in a control circuit for two sets of four hydraulic cylinders 4a to 4d. ing.

In addition, a set of two cylinders 4a, 4b
a second flow divider 12 arranged against
and first and second control valves 1 provided corresponding to the jack cylinders 4a and 4b.
A second shuttle valve 22 is connected between the pipes 14a and 14b connecting the pipes 5a and 15b. Furthermore, a set of two jack cylinders 4c,
Between the pipe lines 14c and 14d that connect the third flow divider 13 disposed relative to the cylinder 4d and the third and fourth control valves 15c and 15d provided corresponding to the cylinders 4c and 4d. A third shuttle valve 23 is connected to.

The outlet of the second shuttle valve 22 is connected to the pipe line 2.
4 is connected to one inlet of the first shuttle valve 21, and the outlet of the third shuttle valve 23 is connected to the other inlet of the second shuttle valve 21 through a conduit 25, respectively.

The outlet of the first shuttle valve 21 is communicated with the oil tank 19 through a pipe line 26.

The first shuttle valve 21 and the oil tank 19
A switching valve 27 is provided between them, and this switching valve 27 is a 4-port, 3-position, solenoid valve. A conduit 10 connecting the first flow divider 9 and the second flow divider 12 is connected to the switching valve 27 via a conduit 28 . The switching valve 27 is switched to the first position when the cylinders 4a to 4d are contracted individually, and the switch valve 27 is switched to the first position when the cylinders 4a to 4d on the rear side are compressed simultaneously. 2 to the H position, and in other cases to the neutral position.

The other configurations of the embodiment shown in FIG. 1 are the same as those shown in FIG. 2, and the same members are designated by the same reference numerals and further explanation will be omitted.

The control circuit of the embodiment shown in FIG. 1 is operated and functions as follows.

(1) When all of the cylinders 4a to 4d are extended, the main control valve 6 is moved to the ``ro'' position, and the first to fourth control valves 15a are
~15d to the C position, and the switching valve 27 to the neutral position.

As a result, the pressure oil discharged from the hydraulic pump 5 is transferred from the main control valve 6 to the extension side pipe line 7 to the first flow divider 9 to the pipe line 10.
11 → second and third flow dividers 12,1
3 → Pipes 14a to 14d → First to fourth control valves 15a to 15d → Pipes 16a to 1
The oil is supplied to the head side oil chambers of the jack cylinders 4a to 4d through 6d.

On the other hand, the pressure oil in the rod side oil chambers of the cylinders 4a to 4d is returned to the oil tank 19 through the branch pipes 8a to 8d, the contraction pipe 8, and the main control valve 6.

Therefore, the jack cylinders 4a to 4
d can all be extended at the same time.

(2) When extending the jack cylinder 4a individually among the jack cylinders 4a to 4d, for example, only the first control valve 15a is switched to the C position, and the other second to fourth control valves 15b to Switch 15d to position 2.

As a result, pressure oil is supplied to the head side oil chamber of the jack cylinder 4a through the same route as in case (1) above, and the pressure oil in the rod side oil chamber of the jack cylinder 4a is supplied to the head side oil chamber of the jack cylinder 4a. It is returned to the oil tank 19 through the same route as in case 1).

On the other hand, the second to fourth control valves 15
The pressure oil that has entered b to 15d is dropped into the oil tank 19.

Therefore, the jack cylinders 4a can be individually extended at the same operating speed as when all the jack cylinders 4a to 4d are extended at the same time.

(3) In FIG. 1, when extending three or less jack cylinders, the same procedure as in (2) above is applied.

(4) When reducing all the cylinders 4a to 4d at the same time, close the main control valve 6.
is switched to the A position, the first to fourth control valves 15a to 15d are switched to the C position, and the switching valve 27 is switched to the neutral position.

Thereby, the pressure oil discharged from the hydraulic pump 5 is supplied to the rod side oil chambers of the cylinders 4a to 4d through the main control valve 6→reduction side pipe 8→branch pipes 8a to 8d.

On the other hand, the pressure oil in the head side oil chambers of the jack cylinders 4a to 4d is transferred from the pipes 16a to 16d to the first
~Fourth control valves 15a to 15d→
Pipe lines 14a to 14d → second and third flow dividers 12, 13 → pipe lines 10, 11 → first flow divider 9 → extension side pipe line 7 → through main control valve 6 to oil tank 19 be returned.

Therefore, all the cylinders 4a to 4d can be reduced at the same time.

(5) For example, when simultaneously shrinking a set of two jack cylinders 4a and 4b as rear jack cylinders for a large crawler crane,
With the main control valve 6 in the A position, the first and second control valves 15a and 15b are
is switched to the C position, the other third and fourth control valves 15c and 15d are switched to the D position, and the switching valve 27 is switched to the H position.

As a result, the pressure oil discharged from the hydraulic pump 5 is supplied to the rod side oil chambers of the jack cylinders 4a, 4b through the main control valve 6→reduction side pipe 8→branch pipes 8a, 8b.

On the other hand, the pressure oil in the head side oil chambers of the jack cylinders 4a, 4b is transferred from the pipes 16a, 16b to the first and second control valves 15a, 15b.
→ Pipe lines 14a, 14b → Second flow divider 12 → Pipe line 10 → Pipe line 28 → Dropped into oil tank 19 through switching valve 27.

At this time, the third and fourth control valves 1
5c and 15d have been switched to position 2,
Pipe lines 14c, 14d, third flow divider 13, pipe line 11 to first flow divider 9
Since the pressure oil does not flow to the first flow divider 9, the diversion port to which the pipe line 10 is connected is narrowed to the maximum extent, but the first and second control valves 15a, 15b→pipe line 14a ,1
As mentioned above, the pressure oil flowing out from the second flow divider 12 through the flow divider 4b is dropped into the hydraulic tank 19 through the switching valve 27.
Even if the 0 side branch port is constricted to the maximum, the jack cylinders 4a and 4b can be contracted at the same operating speed as when all the jack cylinders 4a to 4b are contracted at the same time.

(6) When contracting the jack cylinder 4a individually among the jack cylinders 4a to 4d, for example, move the main control valve 6 to the A position.
the first control valve 15a to position C;
Other second to fourth control valves 15b~
15d to the d position and the switching valve 27 to the t position.

As a result, the pressure oil discharged from the hydraulic pump 5 is supplied to the rod side oil chamber of the jack cylinder 4a through the main control valve 6→reduction side pipe 8→branch pipe 8a.

On the other hand, the pressure oil in the head side oil chamber of the jack cylinder 4a is transmitted through the pipe line 16a → first control valve 15a → pipe line 14a → second shuttle valve 22 → pipe line 24 → first shuttle valve 2.
1 → Pipe line 26 → Oil tank 1 through the switching valve 27
Dropped to 9.

At this time, the second control valve 15b is switched to position 2, and pressure oil does not flow from the pipe line 14a to the second flow divider 12, so the pipe line 14 of the second flow divider 12
Although the branch port to which a is connected is throttled to the maximum extent, the pressure oil flowing out from the first control valve 15a is transferred to the second shuttle valve 22, the first shuttle valve 21, and the switching valve 27, as described above. Since the oil is dropped into the oil tank 19 through the flow divider 12, even if the branch port on the pipe line 14a side is throttled to the maximum by the throttling action of the second flow divider 12, all the jet cylinders 4a to 4d are contracted at the same time. The jack cylinders 4a can be individually contracted at the same operating speed as in the case of the present invention.

Also, when the cylinders 4b are individually contracted, this can be done through the actions of the second shuttle valve 22, first shuttle valve 21, and switching valve 27. When the cylinders 4c and 4d are contracted individually, this can be done through the actions of the third shuttle valve 23, the first shuttle valve 21, and the switching valve 27.

It should be noted that the present invention can be applied to control circuits for three or more sets of hydraulic cylinders, and furthermore, it can be applied to control circuits for hydraulic cylinders in general, in which two or more sets of hydraulic cylinders are arranged. can.

〔Effect of the invention〕

According to the present invention described above, a shuttle valve is connected between the pipes connecting two control valves provided corresponding to each hydraulic cylinder and one flow divider, and the two shuttle valves are connected to each other. The outlet is connected to the inlets on both sides of the main shuttle valve, and the outlet of the main shuttle valve is communicated with an oil tank, and a switching valve is provided between the oil tank and the main shuttle valve, and the main flow divider is selected in advance. By connecting the switching valve to a pipe line connecting each set of two hydraulic cylinders to a flow divider provided for one of the hydraulic cylinders, a set of two hydraulic cylinders and a plurality of sets of hydraulic cylinders can be connected. It has the effect of being able to reduce the hydraulic cylinders individually and at the same operating speed as when all the hydraulic cylinders are reduced at the same time. Therefore, it can be used in the control circuit of a hydraulic cylinder for disassembling and assembling large crawler cranes, etc. When applied, when a difference occurs in the amount of expansion and contraction of the jack cylinder due to unbalanced loads, it can be quickly corrected and work can be carried out safely.

Further, according to the present invention, there is an effect that a set of two preselected hydraulic cylinders can be simultaneously reduced at the same operating speed as when all hydraulic cylinders are simultaneously reduced, and therefore, for example, a large crawler. When disassembling the side frame from the crane's truck frame, it is possible to simultaneously reduce the size of the two hydraulic cylinders on the rear side, reducing the setup time required to remove the side frame. There is profit.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the control circuit of the present invention;
Figures 2 and 3 are side views showing the disassembly work of a large crawler crane performed using two sets of two hydraulic cylinders;
The figure is a diagram showing a conventional technology of a control circuit for a jack cylinder. 4a to 4d...Jax cylinder as a hydraulic cylinder, 5...Hydraulic pump, 6...Main control valve, 7, 8...Extension and contraction side pipes,
9...First flow divider as a main flow divider, 10, 11... Pipe line connecting the first flow divider and second and third flow dividers, 12, 13... Second flow divider , a third flow divider, 14a to 14d...pipe lines connecting the second and third flow dividers and the first to fourth control valves, 15a to 15d...the first to fourth control valves , 16a to 16d...pipe line connecting the first to fourth control valves and the head side oil chamber of the cylinder cylinder, 19...oil tank, 2
1... First shuttle valve as a main shuttle valve, 22, 23... Second and third shuttle valves, 24, 25... Outlets of the second and third shuttle valves and the first shuttle valve. Pipe line connecting the inlet, 26...Pipe line connecting the outlet of the first shuttle valve and the oil tank, 27...Switching valve, 28
... A conduit connecting the first flow divider and the second flow divider, and a conduit connecting the switching valve.

Claims (1)

[Claims] 1 Hydraulic cylinders arranged in a plurality of sets of two, a main control valve, an extension side pipe line and a contraction side pipe line connecting the main control valve and each hydraulic cylinder, and a main flow divider provided therein; a flow divider provided for each set of two hydraulic cylinders and connected to the main flow divider; and a flow divider provided between the flow divider and each hydraulic cylinder. In a control circuit for a hydraulic cylinder having a control valve, a shuttle valve is connected between a pipe line connecting two control valves provided corresponding to each hydraulic cylinder and one flow divider; The outlets of the two shuttle valves are connected to the inlets on both sides of the main shuttle valve, and the outlet of the main shuttle valve is communicated with an oil tank. A switching valve is provided between the oil tank and the main shuttle valve, and the main shuttle valve Control of a hydraulic cylinder, characterized in that a pipe line connecting the divider and a flow divider provided for one set of two hydraulic cylinders selected in advance, and the switching valve are connected by a pipe line. circuit.