JPS61103003A - Control circuit of hydraulic cylinder - Google Patents

Abstract

PURPOSE:To drive a selected hydraulic cylinder promptly by connecting the first flow divider to the discharge side of a hydraulic pump, and connecting the second, third flow dividers and a control valve to the discharge side of the first flow divider. CONSTITUTION:The first flow divider 30 is connected to a hydraulic pump 5, and the second and third flow dividers 33, 34 are connected to the first flow divider 30. Jack cylinders 4a, 4b, 4c, 4d are connected to the second and third flow dividers 33, 34 through the first, second, third and fourth flow control valves 36a, 36b, 36c, 36d. In this arrangement, the jack cylinders are individually, or plural selected cylinders are simultaneously, or all the cylinders are simultaneously contracted, and the prompt operation speed can be attained.

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 an outrigger gear cylinder (hereinafter referred to as a hydraulic cylinder) used during disassembly and assembly of large crawler cranes, truck cranes, etc. The present invention relates to a hydraulic cylinder control circuit suitable for controlling a hydraulic cylinder (referred to as a tsuki cylinder).

[Conventional technology]

When large crawler cranes and truck cranes are transported on roads, they are subject to legal restrictions regarding weight and height, so they must be disassembled into an upper rotating body and a lower traveling body using a jack cylinder. Transport.

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

As shown in these figures, when disassembling the upper rotating body 1 and the lower traveling body 2 from their connection parts 3, two pieces are attached to the front, rear, left and right sides of the upper rotating body 1, and two pieces are separated. The arranged jack cylinders 41 to 4dt are extended and separated into the upper rotating body 1 and the lower traveling body 2 at the connecting portion 3. At this time, since there is usually a difference in the loads applied to the four jack cylinders 4&~4d, a difference occurs in the amount of expansion and contraction. As a result, the revolving upper structure 1 tilts with respect to the ground, resulting in a very dangerous situation. In order to correct this condition, it is necessary to extend and retract the jack cylinders 4&~4dt individually.

Incidentally, among the above-mentioned jack cylinders 41 to 4d, for example, the jack cylinders 4m and 4b form one set as a rear jack cylinder, and the jack cylinder 4c.

4d constitutes another set as a front side cylinder.

1″″.

Next, FIG. 4 shows a prior art control circuit for a jack cylinder disclosed in Japanese Patent Application Laid-Open No. 56-109904f''.

The control circuit shown in this figure includes a hydraulic pump 5, a main control valve 6, and a valve 111 connected thereto.
The extension side conduit 7 and the contraction side conduit 8, and this contraction side conduit 8
branch pipes 8&~8d connecting the rod-side oil chambers of the cylinders 4a-4d, a first flow divider 9 as a main 70-divider connected to the extension-side pipe 7, and a first flow divider 9 as a divider; 1 set of hard cylinders 4m, 4b
and a second 70-divider 9 connected to the first 70-divider 9 via conduits 10 and 11. Third flow divider 12, 13
and valves are provided corresponding to the respective jack cylinders 4a to 4d to valve the pipe lines 14a to 14d. The first to fourth control valves 15a to 15d connected to the third flow pipers 12 and 13;
Pipes 16a to 16d connecting the control valves 15 and ~15d of the cylinder head side oil chambers (hereinafter referred to as head side oil chambers) of the relevant jack cylinders 48 to 4d, and bypasses connected to these pipelines 16a to 16d. Branch pipe 17
The bypass line 17 followed by &~17d and this bypass V! A fifth control valve 18 and an oil tank 19 are provided.

The control circuit is then operated as follows.

■ When extending all the cylinders 4a to 4d' at the same time, set the main control valve 6 to the (b) position and set the first to fourth control valves 15a to 15dt.
- Switch the fifth control valve 18 to the 79 position, which is the operating position, and the (E) position, 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 7 to the first flow divider 9 to the pipes 10 and 11 to the second pipe. Third flow divider 12, 13 → Pipe lines 14a to 14d → First to
Fourth control valves 15a to 15d → pipe line 16a
~16dk and is supplied to the head side oil chambers of the jack cylinders 41~4d.

On the other hand, the pressure oil in the cylinders 4a to 4d C) ELLAD oil extraction chamber is transferred to branch pipes 8a to 8d-+reduction side pipe 8.
→It passes through the main control valve 6 and is returned to the oil tank 19.

Therefore, each of the jack cylinders 4a to 4d simultaneously extends.

■ When extending the jack cylinder 4a individually among the jack cylinders 4- to 4d, the first control valve 15 corresponding to the jack cylinder 4a is opened.
& is switched to the f9 position, which is the operating position, and the other 2nd to
The fourth control valve 15b-15d' is switched to the neutral position.

Accordingly, 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 4de are extended simultaneously. 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 4& is extended, and the other jack cylinders 4b to 4d are not extended.

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

■ When all the cylinders 4a to 4d are to be compressed at the same time, the main control valve 6 is moved to the (A) position, the first to fourth control valves 15a to 15d are moved to the operating position (C), and the main control valve 6 is moved to the (A) position, which is the operating position. The control valve 18 of No. 5 is switched to the (E) position, which is the neutral position under normal conditions.

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 to the branch pipe 8a.
It passes through ~8d and is supplied to the rod side oil chamber of the jack cylinder 4&~4d.

At this time, the pressure oil in the head side oil chambers of the jack cylinders 4a to 4d flows through the pipes 16a to 16d→the first to fourth control valves 15a to 15d→t; Third flow divider 12, 13→pipe line 10.
11→first flow divider 9→extension side pipe 8→main control valve 6 and is returned to the oil tank]9.

Therefore, each of the jack cylinders 41 to 4d performs the contraction operation at the same time.

! . Shiny/! J 71-4a~4dO,! z
J, □yo.

When a timing error occurs and any of the cylinders 4a to 4d does not contract to the stroke end, the fifth control valve 18f is switched to the operating position.

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

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

However, with the conventional control circuit, it is practically impossible to reduce the size of the jack cylinders 4&-4dt individually or at the same time in a system where four jack cylinders are provided.

That is, for example, when trying to individually contract the cylinders 4a, the main control valve 6 is set to 0).
In position 1, the first control valve 15a'ii (c) corresponding to the jack cylinder 4&, the other 2~
Switch to the fourth Funtrol pulp 15b to 15dt'' 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 to the branch pipe 8a.
The oil flows through the cylinder toward the rod-side oil chamber of the cylinder 41.

On the other hand, the pressure oil in the head side oil chamber of the jack cylinder 4a is controlled by the first controller, trol pulp 15 &, because it has been switched to the (c) position, so that the pressure oil in the head side oil chamber of the jack cylinder 4a is controlled by the conduit 16 & → the first controller on the circuit. Valve 15 a → Pipe line 14 m... Second flow divider 12 → Pipe line 10 → First flow divider 9 → Extension side pipe line 7 → Main control valve 6 so that it flows into oil tank 19 appear.

However, the second to fourth control valves 15b to 15
The pipes 16b to 1 are connected to the head side oil chambers of the cylinders 4b to 4d.
6d is the second to fourth control valves 15b to 1;
5d, the 2nd. Pressure oil does not flow to the third flow divider 12, 13 side. As a result, the second flow divider 12
Due to its function, the branch port to which the pipe line 14a is connected is restricted to the maximum extent. Therefore, the flow rate of the pressure oil flowing through the head side oil chamber of the gear cylinder 4a → pipe line 16 & → first control valve 15 & → pipe line 14at- to the second flow divider 12 becomes extremely small, The contraction operation of the cylinder 4& becomes extremely slow, and the individual contraction operation of the cylinder 4& becomes practically impossible.

Similarly, it is practically impossible for the other jack cylinders 4b to 4d.

However, when disassembling and assembling a large crawler crane, the loads acting on the four jack cylinders 4 and ~4d tend to become unbalanced, and the jack cylinder 48
A difference occurs in the amount of expansion/contraction of the cylinders 4a to 4d, and in order to correct this, the force is applied to individually contract the jack cylinders 4a to 4d, and the control circuit shown in Fig. 4 is used to simultaneously contract three or less jack cylinders. There are times when you want to do so.

In contrast, there is a problem that cannot be addressed by the conventional control circuit.

[Problem that the invention seeks to solve]

The purpose of the present invention is to solve the problems of the prior art and to solve the problems of the prior art.
Hydraulic cylinders without a set or in multiple sets are individually
Another object of the present invention is to provide a hydraulic cylinder control circuit that can rapidly contract a plurality of selected hydraulic cylinders at the same time, and can quickly extend and contract the hydraulic cylinders.

[Means for solving problems]

The present invention provides a hydraulic pump with at least one flow collecting port and two
A main flow divider is connected to the main flow divider that can evenly divide the flow to the separate flow ports.A main flow divider that has the same function as the main flow divider and is arranged to have one for each set of two hydraulic cylinders is connected to the main flow divider. 4-port/3-port flow divider is connected to each hydraulic cylinder.
Position: PR5ifiO=r7). -/L/ /
% /l/ 7”□1 Eh. Connect the P port of each control valve to one of the branch ports of the relevant flow divider, connect the R port to the oil tank, and connect the A port to the head of the relevant hydraulic cylinder. Connect to the side oil chamber, B bow) t-
It is characterized by being connected to the head side oil chamber of the hydraulic cylinder.

[Effect]

In the present invention, when contracting the hydraulic cylinders individually or simultaneously, the control valve corresponding to the hydraulic cylinder to be contracted is turned to the contracting side (example position in FIG. 1). switch, and switch the other control valves to the neutral position. As a result, in the hydraulic cylinder to be contracted, pressure oil flows into the rod side oil chamber through the control valve that has been switched to the above (g) position, and the pressure oil in the head side oil chamber remains the same. (to)
The oil flows to the oil tank through a control valve that is switched to position. On the other hand, since the P and R ports of the control valve switched to the neutral position are connected, the pressure oil flowing into the control valve from the a-divider will flow through the P and R ports of this control valve. It passes through and drops into the oil tank.

Therefore, in this case as well, the same amount of pressure oil can be divided from the two flow divider ports of the flow divider, and the pressure oil in the head side oil chamber of the hydraulic cylinder to be reduced can be diverted through the control valve. Since it can flow directly into the oil tank, the hydraulic cylinders can be quickly deflated individually or in a selected number of hydraulic cylinders simultaneously.

In addition, in the present invention, when the hydraulic cylinder is extended or contracted, the pressure oil on the return side can be returned to the oil tank without passing through a flow divider or a switching valve other than the control valve. can be done.

〔Example〕

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

FIG. 1 shows an embodiment of the present invention, and shows a control circuit for hydraulic cylinders 41L-L4d, each consisting of two hydraulic cylinders arranged in two sets.

In the control circuit of this embodiment, a two-port, two-position switching type electromagnetic valve as a switching valve section is connected to the hydraulic pump 5. This switching 5F28 is for the jack cylinder 4&~4dt.
- It is designed to switch from the neutral position to the (g) position when performing telescoping operations.

A first flow divider serving as a main flow divider is connected to the switching valve A through a conduit 29.

The two flow divider ports connected to the first flow divider are connected to the second flow divider through conduits 31 and 32, respectively. third 70
- dividers 33.34 are connected;

Said 1st. second and third 70-divider (equity);
33 and 34 are configured so that the pressure oil can flow evenly from one collecting port to two dividing ports.

First to fourth control valves 36a to 36d are installed corresponding to the jack cylinders 4a to 4d. These first to fourth control valves 36
The m-36d uses a 4-port, 3-position, PR connection type solenoid valve. Said 1st. The P ports of the second control valves 36m and 36b are connected to the conduit 35&.

35b, the second flow divider is connected to one of each of the two flow divider ports, and the third. The P ports of the fourth control valves 36c and 36d are connected to one of the two branch ports of the third flow divider through conduits 35c and 35dt. In addition, the first to fourth control valves 361L to
The R port of 36d is connected to the oil tank 40 through the pipes 37 &~37d, and the A port is connected to the oil tank 40 through the pipes 38a~38d'i.
The B port is connected to the rod-side oil chamber of the jack cylinders 41-4d through pipes 39&-39d. And the first to fourth control valves 3
6 a to 36 d c. Pressure oil supplied from the branch ports of the second and third flow dividers 33 and 34 through pipes 35 m to 35 dt is transferred from P and R ports to pipes 37 a to 37 d in the neutral position. When the oil is flowed into the oil tank 40 through the oil tank 40 and switched to the extension side position,
Shirt (Kijirinda 41~
When supplying oil to the head side oil chamber of 4d and switching to the contraction side (G) position, P, B port → Pipe line 39 & ~ 39
dt" and is configured to be supplied to the rod side oil chambers of the jack cylinders 48 to 4d.

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

That is, when stretching the jack cylinders 41 to 4dt, the switching valve connected to the hydraulic pump 5 is switched from the neutral position to the (g) position.

As a result, the pressure oil discharged from the hydraulic pump 5 is transferred from the switching valve section to the pipe line 4 to the first flow divider section to the pipe line 31.
, 32 → 2nd. It flows through the third 70-divider 33.34→pipe line 35a-35dt- to the first to fourth control valves 36m-36d.

When all of the cylinders 41 to 4d are extended, individually extended, all of them are contracted, or individually reduced, the following operations are performed.

(1) When extending all the cylinders 4a to 4dt at the same time, the first to fourth control valves 3
Switch 6m-36d to four positions.

As a result, the pressure oil is transferred to the first to fourth control valves 36.
The oil is supplied to the head side oil chamber of the cylinders 4 and 4d through pipes 38m and 35d-38d.

At this time, the pressure oil in the rod side oil chambers of the jack cylinders 4a to 4d flows through the pipes 39 & ~ 39d → the first to fourth control valves 361 to 36d → tj337a to 37d.
The oil is returned to the oil tank 40 through the

Therefore, all of the above-mentioned jack cylinders 4&~4d,
They can be stretched at the same time.

(2) When extending the jack cylinder 4 & out of the jack cylinders 41 to 4 d individually, only the corresponding first control valve 36 &
position, and the other second to fourth control valves 36b-36d are switched to neutral positions.

As a result, pressure oil is supplied to the head side oil chamber of the jack cylinder 41 through the same route as in the case (1) above,
The pressure oil in the rod-side oil chamber is returned to the oil tank 40 through the same route as in the case (1) above.

On the other hand, the second to fourth control pals 7'36b to 36
The pressure oil flowing into d is applied to the P and R of the second to fourth control valves 36b to 36d, which are switched to the neutral position.
It is dropped into the oil tank 40 through the port.

As a result, the same amount of pressure oil can be diverted from each of the 21st and 3rd 7a-divider ports.

Therefore, the jack cylinders 4& can be extended individually and at the same operating speed as when all the jack cylinders are extended.

Further, when extending each of the other jack cylinders 4b to 4dt individually, the same operation as described above can be carried out, and when extending three or less jack cylinders at the same time in Fig. 1, the same operation can be carried out. This can be done by operation.

(3) When all the cylinders 4&~4d are contracted at the same time, the first to fourth control valves 36
Switch 1 to 36d to (g) position.

ξBy the way, the pressure oil is controlled by the first to fourth control valves 3.
It passes through 6m-36d-e pipe lines 39a to 39dt- and is supplied to the rod-side oil chamber of the jack cylinders 4&-4d.

At this time, the pressure oil in the head-side oil chambers of the jack cylinders 48 to 4d is dropped into the oil tank 40 via the pipes 38a-38d and the first to fourth control valves 36&-36d.

Therefore, all of the cylinders 41 to 4d can be reduced at the same time.

(4) When shrinking the jack cylinders 4&, of the jack cylinders 43 to 4d, individually, the corresponding first control valve 36m only (e)
position, and the other second to fourth control valves 36b to 36d are switched to neutral positions.

In addition to this, the rod of the jack cylinder 4 &
9''d m Wi K u, #NFf2 f3
) O'jh, h Pi D Rjf! r t A
v? Pressure oil is supplied, and the pressure oil in the head side oil chamber is as described above (
The oil is returned to the oil tank 40 through the same route as in case 3).

-J, second to fourth control valves 36b to 36d
The pressure oil flowing into the second to fourth control valves 3
It is dropped into the oil tank 40 through the P and R ports of 6b to 36d.

As a result, the second. Third flow divider.

It becomes possible to divert the same amount of pressure oil from the drain.

Therefore, the jack cylinders 4a can be individually contracted at the same operating speed as when all the jack cylinders are simultaneously contracted.

Furthermore, the same operations as those described above can be used to individually reduce the other jack cylinders 4b to 4d, and the same applies when reducing three or less jack cylinders at the same time in Fig. 1. This can be done by following the steps below.

In this embodiment, as can be seen from the above, when the jack cylinders 4a to 4d extend and contract, the pressure oil on the 1st return side is supplied to the first to fourth control valves 36 and 3.
6d directly into the oil tank 40 through the pipes 37a to 37d, so that the first and second oils are Since there is no need to pass through the third flow divider 30, 33, 34 or the switching valve 28''f, the expansion and contraction operations of the jack cylinders 4&-4d can be performed quickly.

Note that the present invention is not limited to two sets of two jack cylinders, but can also be applied to three or more sets. It can be applied to all cylinders.

〔Effect of the invention〕

According to the present invention described above, a main flow divider capable of equally dividing flow from at least a collector port to two branch ports is connected to the hydraulic pump, and this main flow divider has a function having the same function as that of the main flow divider. Totomo has a flow divider arranged for each set of two hydraulic cylinders, and installs a 4-port, 3-position, PR connection type control valve in correspondence with each hydraulic cylinder. , connect the P port of each control valve to one of the branch ports of the relevant flow divider, connect the R port to the seven oil tank, connect the A port to the head side oil supply of the relevant hydraulic cylinder, and connect the B port to the head side oil supply of the relevant hydraulic cylinder. By connecting the port to the rod-side oil chamber of the relevant hydraulic cylinder, the hydraulic cylinders arranged in pairs and in multiple sets can be connected individually to one or several selected 7'C at the same time, and all the hydraulic cylinders can be connected at the same time. There is an effect that the size can be quickly reduced at the same operating speed as when reducing KM.

Further, according to the present invention, the pressure oil on the return side from the hydraulic cylinder is directly returned to the oil tank from the control valve corresponding to the hydraulic cylinder without passing through a flow divider or other switching valve. Therefore, there is an effect that the hydraulic cylinder can be expanded and contracted quickly.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the present invention applied to a jack cylinder, which is arranged in two sets, and Figs. 2 and 3 show a large crawler using the jack cylinder. A side view and a plan view showing the crane in an disassembled state, and FIG. 4 are circuit diagrams based on the prior art. 4&~4d...Jax cylinder as a hydraulic cylinder, 5...Hydraulic pump, ah...Switching valve for the entire circuit,
Add... Main 70 - first flow divider as divider, 31. 32... First flow divider and second flow divider. Pipeline connecting the third 70-Deipida, a, 3
4...The second flow divider, one for each set of two hydraulic cylinders. 3rd flow divider, 35&~35d...2nd. 3rd flow pipe [pipe line connecting the P ports of the 1st to 4th control valves, 36m = 36d... 4-port, 3-position, PR connection type control installed in correspondence with the hydraulic cylinder Valves, 37 & ~ 37d... Pipe line connecting the R port of the first to fourth control-pulp and the oil tank, 38 & ~ 38d... A port of the first to fourth control valves and the jack cylinder ' Pipes connecting the head side oil chamber, 391 to 39d... Pipes connecting the B ports of the first to fourth control valves and the rod side oil chamber of the jack cylinder, 40... Oil tank .

Claims (1)

[Claims] In a control circuit for controlling hydraulic cylinders arranged in sets of two or more, the hydraulic pump is connected to a main flow divider capable of equally dividing flow from at least a collection port to two branch ports. , this main flow divider has the same function as this and the above two 1
One flow divider is connected to each hydraulic cylinder in the set, and a 4-port, 3-position, PR connection type control valve is installed corresponding to each hydraulic cylinder, and each control valve's P Connect the port to one of the branch ports of the flow divider, connect the R port to the oil tank, connect the A port to the oil chamber on the cylinder head side of the hydraulic cylinder, and connect the B port to the rod side of the hydraulic cylinder. A control circuit for a hydraulic cylinder characterized by being connected to an oil chamber.