KR100559289B1 - hydraulic circuit of having float function - Google Patents

Abstract

The hydraulic fluid from the head side and the rod side of the boom cylinder is guided to the hydraulic tank, and the boom is lowered by its own weight to stop the operation without using the hydraulic pump side hydraulic fluid.The float function is added to the joining split of the main control valve. It is possible to reduce the cost by reducing the number of parts.It is installed in at least two hydraulic pumps, a hydraulic cylinder connected to and driven by the hydraulic pump, and a flow path between the hydraulic pump and the hydraulic cylinder. In the boom confluence hydraulic circuit having a boom confluence spool for condensing the hydraulic fluid discharged from the plurality of hydraulic pumps to supply to the hydraulic cylinder,

A first inner passage for connecting the hydraulic pump and the large chamber of the hydraulic cylinder is formed on one side of the boom confluence spool, and a second inner passage for connecting the hydraulic oil from the hydraulic pump to the hydraulic tank on the other side of the boom confluence spool. A third internal passage is formed which joins the hydraulic oil from the small chamber and the large chamber of the cylinder and connects it to the hydraulic tank.

Stop operation, energy saving, boom joining, float function, control valve

Description

Hydraulic circuit of having float function

1 is a cross-sectional view of a control valve having a float function according to the prior art,

2 is a hydraulic circuit diagram for boom joining having a float function according to the present invention;

3 is a cross-sectional view of a control valve having a float function according to the present invention.

* Explanation of symbols used in the main part of the drawing

One; 1st hydraulic pump

2; 2nd hydraulic pump

3; Boom Joining Split

  3a; First internal passage

  3b; Second internal passage

  3c; Third internal passage

4; Bucket Driving Spool

5; Boom Drive Sprocket

6; Boom cylinder

7; RCV

8,9; Boom Pilot Pilot Aisle

10,12; Pilot passage for boom down

11; Solenoid valve

13,14,15,16; Passage

The present invention relates to a hydraulic circuit for boom confluence having a float function to stop the operation while lowering the boom by its own weight without using the hydraulic oil discharged from the hydraulic pump during the flat stop operation using an excavator.

More specifically, the hydraulic fluid on the head side and the rod side of the boom cylinder is guided to the hydraulic tank, and the boom is lowered by its own weight to stop the operation without using the hydraulic pump side oil, and to the joining spool of the main control valve. The present invention relates to a hydraulic circuit for boom joining having a float function in which a float function can be added to reduce the number of parts and thus a cost cost.

In general, when the flat stop operation using an excavator, smoothing the flat operation, the stop operation corresponding to the uneven surface due to the high and low working surface and the hydraulic fluid discharged from the hydraulic pump, that is, the boom cylinder The hydraulic oil discharged from the hydraulic pump can be used for other work equipments as the head side and rod side hydraulic fluids communicate with each other to guide the hydraulic tank and lower the boom by its own weight. Is to take advantage of the float function.

1 is a cross-sectional view of a control valve for boom joining having a float function according to the prior art.

As shown, the boom cylinder f is connected to the hydraulic pump not shown, and is installed in the flow path between the hydraulic pump and the boom cylinder f, and is switched when the pilot signal pressure Pi is applied to the boom cylinder f. The valve block c for controlling the flow direction of the hydraulic oil supplied to the valve c is installed in a slidable manner, and the pilot signal pressure Pi mounted at one end of the valve block c to switch the spool d. (C) is formed, and a cap (a) in which an elastic member (b) for returning the spool (d) to the initial position is released when the pilot signal pressure is released.

In the drawing, reference numeral "e" denotes a high pressure passage for supplying high pressure oil from the hydraulic pump to the small chamber g of the hydraulic cylinder f through the flow path r, and k denotes a large chamber of the hydraulic cylinder f. l) and a low pressure passage for guiding hydraulic oil from the small chamber (g) to the hydraulic tank through the flow path (m).

Therefore, when the flat stop operation is to be performed by lowering the boom, the pilot signal pressure Pi for boom down according to the operation of a separate stop operation lever is supplied to the inside of the cap a formed at the right end of the elastic member ( High pressure hydraulic fluid discharged from the hydraulic pump (not shown) by switching the spool (d) in the valve block (c) to the left side in the drawing (state shown in Fig. 1), after defeating the elastic force of b) Is supplied to the small chamber (g) of the hydraulic cylinder (f) via the passage (e, q, r) in order.

At this time, the hydraulic fluid (g) side of the hydraulic cylinder (f) is connected to the hydraulic tank through the low pressure passage (k) via the passage (r) and the pocket (i, j) of the valve block (c) in turn, The hydraulic oil on the large chamber l side of the hydraulic cylinder f is connected to the hydraulic tank via the low pressure passage k through the pockets n and o formed in the passage m and the valve block c in turn. .

Thus, in order to perform the flat stop operation while lowering the excavator boom, the hydraulic oil discharged from the hydraulic pump is used, and the hydraulic operation is conducted to guide the head side and the rod side hydraulic fluid of the hydraulic cylinder to the hydraulic tank. It is not possible to take the main energy saving effect of the float function to be used, and a separate valve block having a float function is added to the main control valve of heavy equipment, thereby increasing the cost and manufacturing cost due to the increase in the number of parts. Will have

SUMMARY OF THE INVENTION An object of the present invention is to provide a hydraulic circuit for joining a boom having a float function to save energy by supplying a part of the hydraulic pump side hydraulic oil to another actuator by lowering the boom by its own weight during a flat stop operation using an excavator. It is.

Another object of the present invention is to add a float function to the joining spool of the main control valve used when the boom is raised, so that a separate part for the float function is unnecessary, thereby reducing the number of parts and significantly reducing the cost and manufacturing cost. It is to provide a hydraulic circuit for boom joining having a float function to enable.

The object of the present invention described above is at least two hydraulic pumps, a hydraulic cylinder connected to and driven by the hydraulic pump, and installed in a flow path between the hydraulic pump and the hydraulic cylinder and switched upon application of a switching signal pressure to supply a plurality of hydraulic pressures. In the boom confluence hydraulic circuit having a boom confluence spool for joining the hydraulic fluid discharged from the pump to supply to the hydraulic cylinder,

A first inner passage for connecting the hydraulic pump and the large chamber of the hydraulic cylinder is formed on one side of the boom confluence spool, and connecting the hydraulic oil from the hydraulic pump to the hydraulic tank on the other side of the boom confluence spool 2 is achieved by providing a hydraulic circuit for boom joining having a float function, characterized in that a third inner passage is formed which joins the inner passage and the hydraulic oil from the small chamber and the large chamber of the hydraulic cylinder to connect to the hydraulic tank. .

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, which are intended to explain in detail enough to enable those skilled in the art to easily carry out the present invention. This does not mean that the technical spirit and scope of the present invention is limited.

As shown in Figures 2 and 3, the present invention is at least two or more hydraulic pumps (1, 2), the hydraulic cylinder (6) connected to the hydraulic pump (1, 2) and driven, the hydraulic pump (2) And a boom driving spool (5) installed in the flow path between the hydraulic cylinder (6) and switching the pilot signal pressure according to the RCV (7) operation to control the flow direction of the hydraulic oil supplied to the hydraulic cylinder (6); Is installed in the flow path between the hydraulic pump (1) and the hydraulic cylinder (6) and is switched when the pilot signal pressure is applied according to the operation of the RCV (7) to convert the hydraulic oil of the hydraulic pump (1) from the hydraulic pump (2) It is applied to the hydraulic circuit of heavy equipment provided with the boom joining spool 3 for joining the hydraulic oil supplied to the large chamber 6b of 6).

Accordingly, the hydraulic circuit for boom confluence having a float function according to the present invention includes a passage 15 through the large chamber 6b of the hydraulic pump 1 and the hydraulic cylinder 6 on one side of the boom joining spool 3. The first inner passage (3a) is formed to connect through the (2), the second inner passage (3b) for connecting the hydraulic oil from the hydraulic pump (1) to the hydraulic tank 18 on the other side of the boom joining spool (3) And a third internal passage 3c for joining the hydraulic oil from the small chamber 6a and the large chamber 6b of the hydraulic cylinder 6 through the passages 15 and 16 to connect to the hydraulic tank 18. do.

In the figure, reference numeral 4 denotes a bucket driving spool installed in the discharge passage of the hydraulic pump 2, and 11 denotes a flow path between the RCV 7 and the boom driving spool 5 and the boom joining spool 3. A solenoid valve for selectively controlling the pilot signal pressure Pi applied to the boom driving spool 5 and the boom joining spool 3.

Hereinafter, the operation of the boom confluence control valve having a float function according to the present invention will be described with reference to the accompanying drawings.

① First, the process of lowering the boom to perform a general operation using an excavator will be described with reference to FIG.

When the driver operates the lever of the RCV 7 to the boom-down side, the pilot signal pressure Pi for the boom down passing through the RCV 7 is the pilot passage 10-solenoid valve 11 (Fig. State shown in Fig. 2)-is applied to the right end of the boom driving spool 5 in turn via the pilot passage 12 to switch the inner spool to the left in the drawing. As a result, the hydraulic oil discharged from the second hydraulic pump 2 passes through the spool 5 that is switched through the parallel passage 23 through the check valve 24 in sequence, and then booms along the passage 14. The small chamber 6a of the cylinder 6 is supplied.

At this time, the passage 16 connected between the small chamber 6a and the boom joining split 3 is blocked by the boom joining split 3 that maintains neutrality, and the large chamber 6b of the boom cylinder 6 is closed. As for the hydraulic fluid on the side, the passage 15 which connected the large chamber 6b and the boom joining spool 3 is blocked by the boom joining spool 3.

Accordingly, the hydraulic oil from the large chamber 6b of the boom cylinder 6 causes the boom driving sprocket 5 to be switched along the passage 13 connected between the large chamber 6b and the boom driving spline 5. By returning to the hydraulic tank 19 via, the boom of the excavator is gradually lowered.

At this time, the boom confluence spool 3 does not move at all and maintains the neutral state shown in the drawing, while the boom driving spool 5 can be lowered due to the position switching of the boom.

② Next, the process of lowering the boom to perform the flat stop operation using an excavator will be described with reference to FIG.

When operating the lever of the RCV (7) to the boom down, as the pressure switch (not shown in the figure) is operated to switch the solenoid valve 11 to the left in the drawing, the RCV (7) The pilot signal pressure Pi for the boom down passing through) is the right side of the boom confluence spool 3 through the pilot passage 10-the solenoid valve 11 switched to the left direction-the pilot passage 20 in sequence. It is applied to the stage to switch the internal spool to the left in the drawing.

Therefore, the hydraulic oil discharged from the first hydraulic pump 1 is returned to the hydraulic tank 18 via the position-changed boom joining splice 3 and the hydraulic oil discharged from the second hydraulic pump 2. Is returned to the hydraulic tank 19 via the bucket driving spool 4 and the boom driving spool 5 in a neutral position in turn.

Thus, the hydraulic oil on the rod side and the head side of the boom cylinder 6 is connected to each other in the passage 3c inside the boom joining spool 3 via the passages 16 and 15 and returned to the hydraulic tank 18. .

Therefore, when using a float function added to one side of the boom joining spool 3 to perform a flat stop operation according to the working surface having an uneven surface by using an excavator, the first and second hydraulic pumps 1 and 2 Since the hydraulic oil is not used at all, a part of the hydraulic oil discharged from these pumps can be switched to another actuator, for example, a bucket driving spool 4 to drive the bucket or supply it to a swing motor.

As a result, it is possible not only to save energy when selecting the float function to perform the flat stop operation, but also to the boom confluence built into the valve body 22 of the main control valve which does not use such a float function when the boom is down. Since it is added to the spool 3, there is no need for a separate valve block for the float function can reduce the cost and manufacturing cost.

③ Meanwhile, the process of lowering the boom to perform a stop operation using an excavator will be described with reference to FIG. 3, which is a cross-sectional view of the control valve for boom joining.

When the driver operates the lever of the RCV to the boom-down side, the pilot signal pressure Pi is supplied through the pilot signal pressure introduction portion 35 formed in the cap 34 at the right end, thereby reducing the elastic force of the elastic member 36. On the drawing, the spool 3 is switched to the left direction. At this time, the hydraulic oil from the high pressure passage 30 of the hydraulic pump is pushed up the check valve 24 and supplied to the parallel passage 31, the parallel passage 31 by the spool (3) is switched to the left direction Is blocked.

At this time, the hydraulic fluid of the small chamber 6a side of the boom cylinder 6 is transferred to the actuator pocket 33 formed in the valve body 22 via the passage 16 so that the notch 3a of the spool 3 is switched. While the hydraulic oil is moved to the hydraulic tank T1, the hydraulic oil of the large chamber 6b side of the boom cylinder 6 is transferred to the actuator pocket 32 via the passage 15, so that the notch 3b of the spool 3 is transferred. Is moved to the tank T2.

That is, the rod side and head side hydraulic fluid of the boom cylinder 6 is returned to the hydraulic tanks T1 and T2 via the notches 3a and 3b of the spool 3.

Therefore, the boom cylinder 6 is gradually lowered according to the variable amounts of the notches 3a and 3b of the spool 3, and thus the boom cylinder 6 is flat and stops while the boom is lowered by its own weight without any load. It is possible to perform the work, stop work corresponding to the uneven surface according to the high and low working surface, and to use no hydraulic oil on the hydraulic pump side, save energy, and for boom confluence of the main control valve Adding float functionality to the splits can reduce cost and manufacturing costs.

④ Meanwhile, a boom joining process, which is a unique function of the boom joining valve, will be described with reference to FIG. 2.

When the driver operates the lever of the RCV 7 to the boom UP side, the pilot signal pressure Pi passing through the RCV 7 passes through the pilot passage 9 of the boom joining spool 3. It is applied to the left end to switch its internal spool in the right direction on the drawing.

At this time, the high-pressure hydraulic oil discharged from the first hydraulic pump 1 is supplied to the large chamber 6b of the boom cylinder 6 through the check valve 24-the position- switched spool 3-the passage 15. At the same time, the pilot signal pressure Pi passing through the pilot passage 8 branched from the pilot passage 9 is applied to the left end of the boom driving spool 5 to switch in the right direction on the drawing.

Thus, the high pressure hydraulic fluid discharged from the second hydraulic pump 2 passes through the inner passage of the parallel passage 23-the check valve 24-the boom driving spool 5 in turn. Since it is supplied to the large chamber (6b) of the boom cylinder (6) through), it is joined with the hydraulic oil discharged from the first hydraulic pump (1) to raise the boom.

⑤ Meanwhile, the boom joining process, which is a unique function of the boom joining valve, will be described with reference to FIG. 3.

When the driver operates the lever of the RCV to the boom side (right side in the figure of FIG. 3), the pilot signal pressure Pi is formed on the cap 37 mounted on the left end of the valve body 22. As it is supplied through the inlet port 38, the elastic force of the elastic member 36 embedded in the cap 34 mounted on the left end is overcome, and in the drawing, the spool 3 is switched to the right direction.

At this time, the hydraulic oil from the high pressure passage 30 on the first hydraulic pump 1 side pushes up the check valve 24 upward and notches 3c of the boom joining spool 3 via the parallel passage 31. As it moves to the actuator pocket 32 via the, the hydraulic oil of the actuator pocket 32 is supplied to the large chamber 6b of the boom cylinder 6 through the passage 15, thereby raising the boom.

In this way, when the boom is raised, the hydraulic fluid is joined using the pilot passage 9 and the actuator pocket 32 on one side of the boom joining boom to raise the boom, and when the boom is down using the float function, the boom is joined. The notches 3a and 3b which are connected to the actuator pockets 32 and 33, respectively, are formed in the spool 3 for the hydraulic tank 32 on the large chamber 6b and the small chamber 6a side of the boom cylinder 6; By connecting to (33), the boom can be lowered by the weight of the boom without generating a load on the boom cylinder 6 while controlling the flow rate as the notch 3a formed in the boom joining spool 3. .

Therefore, it is possible to prevent the loss of energy without using the hydraulic oil discharged from the hydraulic pump, it is possible to smoothly perform the stop operation of the uneven curved surface according to the flat stop operation and the high and low working surface.

As described above, the hydraulic circuit for boom joining having a float function according to the present invention has the following advantages.

During the flat stop operation using an excavator, the boom can be lowered by its own weight to save energy by supplying a part of the hydraulic oil discharged from the hydraulic pump to another actuator.

The float function is added to one side of the joining spool of the main control valve of the heavy equipment, which eliminates the need for a separate part for the float function, thereby significantly reducing the cost and manufacturing cost.

Claims (1)

At least two hydraulic pumps, a hydraulic cylinder connected to and driven by the hydraulic pump, and a hydraulic oil installed in a flow path between the hydraulic pump and the hydraulic cylinder and switched upon application of a switching signal pressure are combined and discharged from a plurality of hydraulic pumps. In the boom joining hydraulic circuit having a boom joining spool to be supplied to the hydraulic cylinder by: A first inner passage for connecting the hydraulic chamber and the large chamber of the hydraulic cylinder is formed on one side of the boom joining spool, The second inner passage for connecting the hydraulic oil from the hydraulic pump to the hydraulic tank on the other side of the boom joining spool, and the third inner portion for joining the hydraulic oil from the small chamber and the large chamber of the hydraulic cylinder to the hydraulic tank. Hydraulic circuit for boom joining having a float function, characterized in that the passage is formed.

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