JP2556786Y2 - Cylinder control device - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The invention relates to a cylinder control device provided with a cylinder lowering operation preventing function for preventing a fork from lowering due to an erroneous operation in, for example, a forklift.

(Prior Art) The conventional cylinder control device shown in FIGS. 3 and 4 controls a cylinder C such as a forklift. A proportional solenoid S is provided on one side of a valve body of a spool valve 1 in which a spool 1a is installed. And the spool 1a is switched in accordance with the excitation of the proportional solenoid S, and the supply hydraulic oil supplied from the pump is supplied to the main supply passage 10 formed in the valve body of the spool valve 1.
To lead to.

This supply main path 10 includes a load flow path 11 that is branched from this.
And the load passage 11 is connected to the supply passage 8.
Is communicated to.

A cylinder port 2 is formed in the valve body, and the cylinder port 2 is connected to the bottom chamber 3 of the cylinder C.

An operation check valve 4 is provided in the flow path to the cylinder port 2 in this manner, and in a closed state, the cylinder port 2 is partitioned into a spool side 2a and a cylinder side 2b.

Further, a pilot passage 7 is formed in the valve body, and one end thereof is communicated with the cylinder side 2b via the operation check valve 4, and a solenoid valve 16 is provided at the other end. The pilot passage 7 and the pilot port 6 communicate with each other.

When the spool 1a is held at the neutral position shown in the figure, the pressure oil supplied from the pump P is supplied to the main supply path.
10 flows into the supply passage 8 via the load passage 11.

Here, when the proportional solenoid S connected to one end of the spool 1a is excited to move the spool 1a from the neutral position in the drawing to the right in the drawing, the supply passage 8 and the spool side 2a of the cylinder port 2 are connected to the spool 1a. It communicates via the formed first annular groove 9.

Therefore, the pressure oil that has flowed into the supply passage 8 is further supplied to the cylinder C via the supply passage 8 → the first annular groove 9 → the spool side 2a → the operation check valve 4 → the cylinder side 2b.
And the fork W is lifted.

After that, return the spool 1a to the neutral position shown
Since the supply passage 8 is shut off, the pressure oil is not supplied to the bottom side chamber 3 and the operation check valve 4 is kept closed. Therefore, fork W is held at a desired position.

When the spool 1a is moved from the neutral position to the left in the drawing, a drill hole 18 formed in the spool 1a on the pilot port 6 side is opened, and the hydraulic oil on the cylinder side 2b of the cylinder port 2 is supplied to the orifice 15b. → The first pilot chamber 5 → the pilot port 6 → the drill hole 18 → flows into the return passage 13 via the second annular groove 12.

Therefore, a pressure difference occurs around the orifice 15,
Due to the pressure on the upstream side of the orifice 15, the bopette 4a moves against the spring 4b and opens the seat portion 14.

When the seat portion 14 is opened in this manner, the hydraulic oil in the bottom chamber 3 is released from the cylinder side 2b of the cylinder port 2 to the spool side.
2a → the first annular groove 9 → flows out to the return passage 13 via the outflow hole 19, and the fork W is lowered by its own weight.

Further, when the operator does not work, the solenoid of the solenoid valve 16 is demagnetized and the seat portion 17 is demagnetized.
Close.

When the seat 17 is closed in this way, the pilot passage 7
And the communication with the pilot port 6 is cut off.

Therefore, even if the spool 1a malfunctions, the fork W
Is prevented from descending.

(Problems to be Solved by the Present Invention) In the conventional cylinder control device as described above, the solenoid valve 16 is interposed in the pilot passage, and the solenoid is demagnetized to lower the fork W due to the malfunction of the spool 1a. I was trying to prevent it.

For this reason, in addition to the proportional solenoid S for switching the spool 1a, the solenoid valve 16 must be specially provided.

Therefore, there has been a problem that the cost increases accordingly.

The purpose of this invention is to provide a control device for a cylinder with a low-cost emergency circuit.

(Means for Solving the Problems) In this invention, an operation check is provided in which a main spool is slidably provided in a valve body of a spool valve, and a cylinder port formed in the valve body allows only a flow to a cylinder. A valve is provided, and an orifice is formed in the poppet of the operating check valve to communicate the first pilot chamber of the operating check valve with the cylinder port. The first pilot chamber is communicated with the return passage, and the proportional solenoid is excited. It is assumed that the main spool is switched by the action of a pilot pressure that changes in accordance with the cylinder pressure to supply the pressurized oil to the cylinder port side and to return the return oil to the cylinder port side.

Assuming the above cylinder control device,
With one end of the main spool facing a chamber for guiding pilot pressure, a sub-spool having an annular groove is slidably provided inside the one end of the main spool, and one end of the main spool is closed. A second pilot chamber is provided between one end of the spool and the second pilot chamber communicates with the chamber. On the other hand, the other end of the sub spool faces a spring chamber provided in the main spool. The spring force of the spring provided in the chamber and the pressure action of the second pilot chamber are opposed to each other, and a flow hole communicating the spring chamber and the annular groove is formed in the sub-spool. A through hole communicating the second pilot chamber with the chamber, a first drill hole communicating the annular groove of the sub spool with the return passage, and a transfer of the sub spool. A second drilling hole is formed to communicate or shut off the annular groove and the first pilot chamber, and when the proportional solenoid is demagnetized, no pilot pressure is supplied to the chamber and the second pilot chamber. In addition, the communication between the first pilot chamber and the return passage is interrupted in accordance with the movement position of the sub-spool.

(Operation of the present invention) When the proportional solenoid is demagnetized as described above, pressure oil is supplied to both the chamber facing the one end of the main spool and the second pilot chamber facing the one end of the sub spool. In addition, since the communication between the first pilot chamber and the return passage is interrupted via the sub-spool, the fork can be prevented from lowering due to a malfunction of the main spool only by demagnetizing the proportional solenoid.

If the pilot pressure does not act on the main spool, the main spool does not move. That is, when the pump is stopped and the engine is stopped, the main spool does not move regardless of whether the proportional solenoid is excited.

(Effect of the Present Invention) As described above, the cylinder control device of the present invention can prevent the fork from lowering due to a malfunction of the main spool only by demagnetizing the solenoid. In other words, the function can be obtained as an emergency circuit when the main spool sticks and stops moving during fork lowering. In addition, there is no need to provide a solenoid valve as in the related art, and the cost can be reduced accordingly.

Further, if the pilot pressure does not act on the main spool, the main spool does not move, so that it is possible to prevent the fork from lowering due to an erroneous operation when the pump is stopped, that is, when the engine is stopped.

(Embodiment of the Present Invention) In the embodiment of the present invention shown in FIGS. 1 and 2, a main spool 22 slides in a spool hole 21 formed in a valve body 20 of a spool valve as shown in FIG. They are freely decorated.

Then, cover members 23 and 24 are provided on both left and right sides of the drawing of the valve body.
The cover members 23 and 24 respectively define the chambers R ₁ and R _2, and both ends of the main spool 22 are
R ₁ and R ₂ are projected.

Further, the valve body, but to form a pair of left and right flow paths 33 and 39, the passage 33, as well as to face the one end opening to the chamber R _1, the concatenation of the proportional solenoid S ₁ at the other end A pressure reducing valve V is provided. Then, the pressure oil supplied to the pump port 40, the pressure and vacuum according to the excitation of the proportional solenoid S _1, while being supplied to the flow passage 33 via the pressure reducing valve V, and the proportional solenoid S ₁ When degaussed, the pressure oil supplied to the pressure reducing valve V is returned to the full tank via the drain port 41.

On the other hand, the flow passage 39 has its one end opening causes facing the chamber R _2, the other end is provided with a pressure reducing valve, not shown, connecting the proportional solenoid S _2. The configuration and function of the pressure reducing valve are exactly the same as those of the pressure reducing valve V.

Further, a main spool 22, to its chamber R ₂ side, to form a spool bore 25 along the axis of the main spool 22, slidably sub spool 26 formed with annular grooves 26a in the spool bore 25 Interior.

Further, a holding member 27 is screwed into one end opening of the spool hole 25, and the opening is closed to partition the second pilot chamber 28 between one side of the sub spool 26 and the holding member 27. A spring chamber 29 is defined on the other side of 26.

Then, the mounting of the spring s ₁ in the spring chamber 29, the spring chamber 29 through the flow holes 26b formed in the sub-spool 26, thereby always communicated with the annular groove 26a.

Further, a pair of receiving members 3
With mounting the 7, 38, a spring s ₂ mounted between these receiving members 37 and 38, via the receiving member 37 the spring force of the spring s _2, and so as to act on the main spool 22.

The main spool 22 as described above, in order from the chamber R ₂ end, through hole 30, but forms a first drilled hole 31 and the second drilled hole 32, the first drilled hole 31 is one end Is opened in the second annular groove 35 formed in the main spool 22, and the other end is opened in the annular groove 26a, so that the second annular groove 35 and the annular groove 26a communicate with each other through the first drill hole 31. On the other hand, through hole 3
0 has one end opened in a third annular groove 36 formed in the main spool 22 and the other end in the second pilot chamber 28.
And the through hole 30 of the second pilot chamber 28 → the third annular groove
It communicates with the flow passage 39 via 36.

Since the configuration other than the above is the same as the conventional one, the same reference numerals are given to the same components and the detailed description is omitted.

Thus, when energizing the proportional solenoid S _1, the pump P
Pressure oil discharged from is led to the flow passage 33 via a pressure reducing valve V, the pressure oil is guided to the chamber R ₁ and further through the flow passage 33. Thus, the pressure oil in the chamber R ₁ is derived, the main spool 22 moves against the spring force of the spring s ₂ by the action of the pressure of the pressure oil to move from the neutral position shown in the drawing right . Then, the supply passage 8 communicates with the main spool side 2a of the cylinder port 2 via the first annular groove 34.

Accordingly, the pressure oil flowing into the supply passage 8 is supplied to the bottom chamber 3 of the cylinder C via the supply passage 8 → the first annular groove 34 → the spool side 2a → the operation check valve 4 → the cylinder side 2b. Raise the fork W.

Main spool then to demagnetize the proportional solenoid S ₁
When the valve 22 is returned to the neutral position in the drawing, the supply passage 8 is shut off, so that the pressure oil is no longer supplied to the bottom chamber 3 and the operation check valve 4 is kept closed. Therefore, fork W is held at a desired position.

Furthermore, when energizing the proportional solenoid S _2, the pressure oil discharged from the pump P, is guided to the flow path 39 via a pressure reducing valve (not shown). The pressure oil led to the flow passage 39 further
It is branched and guided in two directions, one of which is a flow passage 39 →
The third annular groove 36 is guided to the second pilot chamber 28 via the through hole 30, and the other is in the flow path 39 → the main spool 22
Is guided to the chamber R ₂ through the drilled hole 37a → receiving drilled hole 38a formed in the member 38 is formed in the gap → receiving member 37 between the outer and the receiving member 37.

Thus, the second pilot chamber 28, the pressure oil in the chamber R ₂ is introduced, the sub-spool 26 by the action of the pressure of the pressure oil guided to the second pilot chamber 28, anti the spring force of the spring s ₁ To the left in the drawing, and the main spool 22
By the action of the pressure of the pressure oil guided to R _2, the drawing-left neutral position shown, moves against the spring force of the spring s _2.

When the sub spool 26 moves to the left in the drawing, the first drill hole
When the main spool 22 moves from the neutral position to the left in the drawing while the 31 and the second drill hole 32 communicate with each other via the annular groove 26a, the second drill hole 32 opens to the pilot port 6.

Then, the second drill hole 32 is formed between the pilot port 6 and the annular groove.
The opening timing of the second drill hole 32a is such that one end of the second drill hole 32 is opened to the pilot port 6 and the other end is opened to the annular groove 26a.
The cylinder control device is configured so as to open smoothly.

After all, when exciting the proportional solenoid S _2, the pilot port 6 communicates with the passage 13 back through the second drilled hole 32 → the annular groove 26a → first drilled hole 31 → the second annular groove 35. The hydraulic oil on the cylinder side 2b of the cylinder port 2 is supplied to the orifice
15 → first pilot chamber 5 → pilot passage 7 → pilot port 6 → second drill hole 32 → annular groove 26a → first drill hole 31
→ It flows into the return passage 13 via the second annular groove 35.

Therefore, a pressure difference occurs around the orifice 15,
The poppet 4a functions in the same manner as in the related art, and
While opening 14, the hydraulic oil in the bottom chamber 3 flows out of the main spool side 2a of the cylinder port 2 to the return passage 13 via the first annular groove 34, and lowers the fork W by its own weight.

If subsequently, to demagnetize the proportional solenoid S _2, passage 39
Since communicates with the tank, the second pilot chamber 28, hydraulic oil in the chamber R ₂ both room is returned to the tank, these pressures of both chambers is eliminated.

The sub spool 26 together with the return to the position shown by the action of the spring force of the spring s _1, main spool 22 returns to the neutral position shown by the action of the spring force of the spring s _2. Therefore, the communication between the first drill hole 31 and the second drill hole 32 is interrupted, and the second drill hole 32 is closed with respect to the pilot port 6, so that the communication between the pilot passage 7 and the return passage 13 is eventually completed. Will be shut off.

As described above, when the communication between the pilot passage 7 and the return passage 13 is interrupted, the pressure difference between the orifice 15 and the orifice 15 disappears, and the poppet 4a functions in the same manner as in the related art, and closes the seat portion 14. Then, the hydraulic oil in the bottom side chamber 3 is prevented from flowing out, and the fork W is prevented from descending from a desired position by its own weight.

Further, by opening the second drilled hole 32 of the main spool 22 to the pilot port 6, when the fork W is lowered, when the main spool 22 is stuck to the stick, the proportional solenoid S ₂ excitation current When the sub-spool 26 is moved to the position shown in FIG.
The communication between the first through hole 32 and the first through hole 31 is interrupted, and the fork W is prevented from descending. When the sub-spool 26 is returned from the relation position shown to the original relation position again, the second drill hole 32 and the first drill hole 31 communicate with each other, and the pilot passage 7 and the return passage
Communication with 13 is restored, and fork W continues its downward movement again.

According to the above-described embodiment, one end of the main spool 22 that moves in accordance with the excitation of the proportional solenoids S ₁ and S ₂ faces the chamber R ₂ , and the annular groove 26 a is formed on the one end side of the main spool 22. the sub spool 26 formed slidably and decorated, and one end of the sub-spool 26 to face the second pilot chamber 28 communicating with the chamber R _2. Further, the first spool hole 31 for communicating the annular groove 26a with the return passage 13 is formed in the main spool 22, and the annular groove 26a communicates with the pilot port 6 according to the movement of the sub-spool 26. the second drilled hole 32 or block the communication form, the to demagnetize the proportional solenoid S ₂ chamber R _2, a second pilot chamber 28
And the communication between the pilot port 6 and the return passage 13 via the sub-spool 26 is cut off.

As described above, since the communication between the first pilot chamber and the return passage is cut off via the sub-spool, the fork can be prevented from lowering due to malfunction of the spool only by demagnetizing the proportional solenoid valve. .

Therefore, there is no need to provide the conventional solenoid valve, and the cost can be reduced accordingly.

Incidentally, to move the sub-spool by controlling the excitation current of the proportional solenoid S _2, or communicates with the passage back to the pilot port, it is possible or block this communication, the main when the fork is lowered Even if the spool sticks and stops moving, you can prevent the fork from lowering or keep it down.

[Brief description of the drawings]

1 and 2 show this embodiment, FIG. 1 is a sectional view of a spool valve, FIG. 2 is a circuit diagram of the cylinder control device, and FIGS. 3 and 4 show a conventional device. FIG. 3 is a sectional view of the spool valve, and FIG. 4 is a circuit diagram. S ₁ , S ₂ …… Proportional solenoid, 1 …… Spool valve, 1a, 22
... Main spool, 2 ... Cylinder port, C ... Cylinder, 4 ... Operate check valve, 4a ... Poppet, 5 ... First pilot chamber, 13 ... Return passage, 15 ...
Orifice, 20: Valve body of spool valve, 26: Sub-spool, 26a: Annular groove, R _2: Chamber, 28: Second pilot chamber, 31: First drill hole, 32: Second Drill hole.

Claims (1)

(57) [Scope of request for utility model registration] A main spool is slidably provided on a valve body of a spool valve, and an operation check valve for allowing only flow to a cylinder is provided on a cylinder port side formed in the valve body. An orifice is formed in the poppet to communicate the first pilot chamber of the operation check valve with the cylinder port, and the first pilot chamber is communicated with the return passage, while the pilot pressure changes according to the excitation of the proportional solenoid. In a cylinder control device for switching the main spool by operation to supply pressure oil to the cylinder port side or to allow return oil to flow out from the cylinder port side, one end of the main spool is connected to a chamber for guiding pilot pressure. And an annular groove is formed inside the one end of the main spool. Provided with a sub-spool slidably, closes one end of the main spool, a second pilot chamber disposed between one end of the sub-spool, the second
While the pilot chamber communicates with the chamber, the other end of the sub-spool faces a spring chamber provided in the main spool, and a spring force of a spring provided in the spring chamber and a pressure of the second pilot chamber. The operation and the opposing structure are formed, and a flow hole communicating the spring chamber and the annular groove is formed in the sub spool, and the main spool is provided with:
A through-hole communicating the second pilot chamber with the chamber, a first drill hole communicating the annular groove of the sub-spool with the return passage, and an annular groove and the first pilot chamber in accordance with the movement of the sub-spool. When the proportional solenoid is demagnetized, no pilot pressure is supplied to the chamber and the second pilot chamber, and the first drilling hole is formed in accordance with the position of the sub-spool when the proportional solenoid is demagnetized. A cylinder control device configured to cut off communication between the pilot chamber and the return passage.