JPH0632263Y2 - Hydraulic pressure supply / discharge device with switchable pressure for hydraulic clamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application Field >> The present invention relates to a hydraulic pressure supply / discharge device for supplying / discharging pressure oil to / from a hydraulic clamp in order to release or fix a solid object such as a work. Among them, regarding the hydraulic pressure supply / discharge device that can switch the clamping pressure of the hydraulic clamp between the high pressure clamping pressure and the low pressure clamping pressure, the clamping pressure can be switched. This is a technology that prevents the fixed object from shifting and shortens the switching operation time.

<Basic structure as a premise> For example, when machining easily deformable workpieces such as the crankcase lid of a gasoline engine with a machine tool such as a machining center, clamp the workpiece on the table with a hydraulic clamp and first perform rough cutting. After the application, finish cutting may be performed.

In this case, at the time of rough finishing, the hydraulic clamp is clamped at a high pressure to increase the clamping force, thereby deepening the cutting depth and accelerating the cutting speed.

At the time of finish cutting, the hydraulic clamp is clamped at a low pressure to reduce the clamping force, thereby reducing the distortion of the work and improving the finish dimension accuracy of the work.

As described above, there is a hydraulic pressure supply / discharge device capable of switching the clamping pressure of the hydraulic clamp, which has a basic structure as follows.

For example, as shown in FIG. 1 to FIG. 4, or FIG. 9 and FIG. 10, a high pressure clamp operation valve 12 is provided between the clamp working oil chamber 9 of the hydraulic clamp 3 and the pressure supply passage 17. Opening to set the high-pressure clamping operation valve 12, supra clamping hydraulic oil chamber 9 from the feed passage 17 to permit the outflow of pressure oil to the clamping hydraulic oil chamber 9 to the high-pressure clamping pressure P ₁ It is configured to be switchable between a state and a valve-closed state in which pressure oil is prevented from flowing out. Further, an unclamping operation valve 13 is provided between the clamp hydraulic oil chamber 9 and the discharge pressure passage 18. The unclamping operation valve 13 is placed in a valve closed state that prevents the pressure oil from flowing out from the clamp hydraulic oil chamber 9 to the discharge pressure passage 18 and in an open state that allows the pressure oil to flow out. It is configured to be switchable.

<< Prior Art >> As a structure for switching the clamping pressure from the high pressure clamping pressure P ₁ to the low pressure clamping pressure P ₂ in the above-mentioned basic structure, conventionally, there are structures shown in FIGS. 9 and 10.

That is, the low pressure clamp operation valve 14 is provided between the pressure supply passage 17 and the clamp working oil chamber 9. The low pressure clamp operation valve 14 is allowed to flow out of the pressure oil from the pressure supply passage 17 to the clamp working oil chamber 9 to set the pressure of the clamp working oil chamber 9 to a predetermined low pressure clamping pressure P ₂ . A valve open state that is set and a valve closed state that prevents the pressure oil from flowing out are configured to be switchable.

Then, from the high pressure clamp A state in which the high pressure clamp pressure P ₁ is supplied to the clamp hydraulic fluid chamber 9 by the high pressure clamp control valve 12, first the high pressure clamp control valve 12 is closed and the unclamp control valve 13 is opened to clamp. The pressure oil is discharged from the hydraulic oil chamber 9 and once in the unclamped state C,
Next, the unclamping operation valve 13 is closed, the low-pressure clamping operation valve 13 is closed, and the low-pressure clamping operation valve 14 is opened to supply the low-pressure clamping pressure P ₂ to the clamp hydraulic oil chamber 9. To switch to.

<< Problems to be Solved by the Invention >> The above conventional structure has the following problems.

(B) The work moves during the switching operation.

When the unclamping state C is reached during the switching operation, the work W may be displaced and a machining dimension error may occur.

(B) The switching operation time is long.

During the switching operation, the four operations of closing the high-pressure clamp operating valve 12, opening the unclamping operating valve 13, closing this operating valve 13, and opening the low-pressure clamping operating valve 14 must be performed in sequence. Operation, it takes a long time. As a result, the operating rate of machine tools such as machining centers decreases.

(C) The cost of automating the switching operation is high.

When automating the switching operation, it is necessary to control the order of the four operations, and the cost of automation is high.

An object of the present invention is to prevent a fixed object such as a work piece from shifting during a switching operation of the clamping pressure, to shorten the switching operation time, and to reduce the cost of automation of the switching operation.

<< Means for Solving the Problems >> To achieve the above object, the present invention is, for example, as shown in FIG. 1 to FIG. 4, FIG. 5 and FIG. 6, FIG. 7, or FIG. In addition, in the basic structure described above, the structure for switching from the high pressure clamping pressure P ₁ to the low pressure clamping pressure P ₂ is configured as follows.

A low pressure clamp operating valve 14 is provided in parallel with the unclamping operating valve 13 between the clamp hydraulic oil chamber 9 and the exhaust pressure passage 18, and the low pressure clamping operating valve 14 is When the pressure in the clamp hydraulic fluid chamber 9 is in the closed state in which the pressure hydraulic fluid flows out of the clamp hydraulic fluid chamber 9 to the discharge pressure passage 18, the pressure in the clamp hydraulic fluid chamber 9 changes from the high pressure clamping pressure P ₁ to a predetermined low pressure clamping pressure. It is configured such that it can be switched to a relief state in which pressure oil is allowed to flow out until the pressure drops to P ₂ .

It should be noted that the above-described low-pressure clamp operating valve 14 is configured by an on-off valve 37 and a relief valve 38 connected in series as shown in FIGS. 1 to 4, and in FIGS. 5 and 6. As shown, the relief valve 68 may be configured by a relief two-stage switching relief valve 68. Further, as shown in FIG. 7, it is conceivable that the low pressure clamp operating valve 14 and the unclamp operating valve 13 are integrally configured as a relief three-stage switching type relief valve 88.

<< Operation >> The present invention operates as follows, for example, as shown in FIGS. 1 to 4.

That is, at the time of high pressure clamping, the operation valve 13 for the amplifier lamp is
The high pressure clamp operation valve 12 is opened with the low pressure clamp operation valve 14 closed. Then, the clamp hydraulic oil chamber 9 is set to the high pressure clamping pressure P ₁ .

When switching from the high pressure clamp state A to the low pressure clamp state B, first, the high pressure clamp operation valve 12 is
Is closed and then the low pressure clamp operating valve 14 is opened. Then, a part of the pressure oil in the clamp hydraulic oil chamber 9 is released from the low pressure clamp operation valve 14 and the pressure in the clamp hydraulic oil chamber 9 is reduced to the low pressure clamp pressure P ₂ .

When switching from the low pressure clamp state B to the unclamp state, the unclamp operation valve 13 may be opened.

At the time of the above switching operation, the high pressure clamp operation valve 1
The opening / closing operation of the unclamping operation valve 13 is not interposed between the valve closing operation of 2 and the opening operation of the low pressure clamp operation valve 14, and the hydraulic pressure in the clamp working oil chamber 9 is in the high pressure clamped state P.
_{Since the} low pressure clamp state P ₂ is continuously switched from ₁ and the unclamp state does not occur during the switching, the work W is prevented from shifting.

Further, the above switching operation only requires two operations, that is, closing operation of the high-pressure clamp operation valve 12 and opening operation of the low-pressure clamp operation valve 14. From the four operations of the conventional structure, the unclamp operation valve can be operated. Since the two operations of the valve opening operation 13 and the valve closing operation 13 can be omitted, the operation time can be shortened.

Furthermore, when automating the switching operation, the operating point is only the low-pressure clamp operation valve 14, so the cost for automation is low.

<< Effects of the Invention >> The present invention has the following effects because it is configured and operates as described above.

(B) It is possible to prevent the work piece from shifting.

During the switching operation, the hydraulic pressure in the clamp working oil chamber is continuously switched from the high pressure clamp state to the low pressure clamp state, and the unclamped state does not occur, so that the work is prevented from shifting. As a result, it is possible to eliminate a processing dimensional error due to the deviation of the work.

(B) The switching operation time can be shortened.

At the time of the switching operation, it is possible to omit the two operations of opening and closing the unclamping operation valve, so that the switching operation time is short.

This improves the operating rate of machine tools such as machining centers.

(C) The cost of automating the switching operation is low.

When automating the switching operation, the operating point is only the operation valve for the low pressure clamp, so the cost for automation is low.

In addition, when the above-mentioned low-pressure clamp operation valve is constituted by an on-off valve and a relief valve which are connected in series, the following effects are further exhibited.

That is, the on-off valve and the relief valve can be made individually,
By constructing the on-off valve as a seat valve type, it is possible to easily make the entire low-pressure clamp operation valve non-leak, so that hydraulic pressure supply in the clamped state can be stopped to reduce energy consumption.

<< Embodiment >> An embodiment of the present invention will be described below with reference to the drawings.

(First Embodiment) FIGS. 1 to 4 show a first embodiment.

In the overall system diagram of FIG. 1, a work W placed on a fixed base 2 of a work machine work pallet 1 is pressed by a plurality of hydraulic clamps 3 via a hydraulic pressure supply / discharge device 4 and a hydraulic pump (hydraulic pressure source) P. It can be fixed. The work pallet 1 is separated from the hydraulic pump P in a state where the work W is pressed and fixed, and is carried into the table of the cutting machine (not shown), and after the work W is cut, it is carried out from the table. It is connected to the hydraulic pump P again to release the press-fixed state of the work W.

The hydraulic clamp 3 is configured such that a piston 7 of a double-acting hydraulic cylinder 6 drives a clamp tool 8, and a clamp working oil chamber 9 and an unclamp working oil chamber 10 are formed above and below the piston 7, respectively. . Also, the hydraulic pressure supply / discharge device 4
Is configured by connecting a high pressure clamp operation valve 12, an unclamp operation valve 13 and a low pressure clamp operation valve 14 to a clamp operating oil chamber 9 of the hydraulic clamp 3 and operates as shown in FIG. That is, the high pressure clamping pressure P ₁ (about 60 kg / cm ² ) is supplied from the high pressure clamping operation valve 12 to the clamp hydraulic oil chamber 9 and is maintained in the high pressure clamping state A, and the workpiece W is roughed under the high clamping force state. Apply processing. Next, from the high pressure clamp state A, the high pressure clamp operation valve 12 is closed and the low pressure clamp operation valve 14 is opened, so that the pressure in the clamp working oil chamber 9 is increased to the high pressure clamp pressure P _1.
(Approx. 60 kg / cm ² ) to P ₂ for low pressure clamp (Approx. 35 kg / c
The pressure is reduced to m ² ) and switched to the low pressure clamp state B, and the strain of the work W is reduced in the low clamping force state to reduce the work W
It is designed to be finished.

Hereinafter, the hydraulic pressure supply / discharge device 4 will be described.

The clamp working oil chamber 9 of the hydraulic clamp 3 is connected to the hydraulic pump P via the clamp supply / discharge oil passage 15, the pressure supply valve 16a of the clamp direction switching valve device 16, and the pressure supply passage 17 in this order. , Is connected to the oil tank 19 via the exhaust pressure valve 16b and the exhaust pressure passage 18 of the clamp direction switching valve device 16. The pressure supply passage 17 is provided with a high clamp pressure setting pressure reducing valve 20 and a pressure supplying rapid joint 21, and the discharge port of the hydraulic pump P communicates with the oil tank 19 via a pressure setting relief valve 22. . Further, the exhaust pressure passage 18 is provided with a rapid exhaust pressure joint 23. Reference numeral 24 is a pressure supply branch passage communicating with another hydraulic clamp in the work pallet 1, and reference numeral 25 is a discharge pressure branch passage. Further, the unclamping hydraulic oil chamber 10 of the hydraulic clamp 3 is connected to the secondary side of the pressure reducing valve 20 via the unclamping supply / discharge oil passage 7 and the pressure feeding valve 28a of the unclamping direction switching valve device 28 in order. In addition, the unclamping direction switching valve device 28 is communicated with the exhaust pressure passage 18 via the exhaust pressure valve 28b.

Then, the clamp direction switching valve device 16 is connected to the exhaust pressure valve 16b.
Directional switch device 2 for unclamping while switching to the side
By switching 8 to the pressure supply valve 28a side, the pressure oil in the clamp working oil chamber 9 is discharged to the discharge pressure passage 18, and the hydraulic clamp 3 is unclamped. On the other hand, the clamping directional switching valve device 16 is switched to the pressure supply valve 16a side, and the unclamping directional switching valve device 28 is replaced with the exhaust valve 28.
By switching to b, from the hydraulic pump P to the pressure supply passage 1
The oil pressure supplied to 7 is supplied to the clamp working oil chamber 9 at the high pressure clamping pressure P ₁ set by the pressure reducing valve 20. Although the temperature compensating accumulator 30 and the hydraulic pressure gauge 31 are branched from the clamp supply / discharge oil passage 15, when the amount of heat received by the hydraulic clamp 3 and the hydraulic supply / discharge device 4 is small, the accumulator 30 is not used. It may be omitted.

The pressure supply valve 16a of the clamp direction switching valve device 16 described above.
The decompression valve 20 and the pressure supply quick joint 21 constitute the above-mentioned high-pressure clamp operation valve 12, and the same as the above-mentioned clamping direction switching valve device 16 exhaust pressure valve 16b and exhaust pressure quick joint 23, the above-mentioned unclamp operation valve 13 is formed. Is configured.

Further, the low-pressure clamp operation valve 14 changes the hydraulic pressure of the clamp working oil chamber 9 to the high-pressure clamp pressure P _{1 in the} valve opening operation state.
Is set to P ₂ for low pressure clamping, and the inlet 14a of the operation valve 14 for low pressure clamping is communicated with the clamp working oil chamber 9 via the pressure relief passage 33 and the oil supply / discharge passage 15 for clamping. At the same time, the outlet 14b communicates with the exhaust pressure passage 18. Reference numeral 34 is a reservoir tank.

The low-pressure clamp operating valve 14 is the pneumatic cylinder 36.
The relief valve 38 is connected in series with an opening / closing circle 37 that is opened / closed by, and is as shown in the vertical sectional view of FIG. The opening / closing valve 37 is formed by forming an opening / closing valve chamber 41 and an opening / closing valve seat 42 in the upper portion of the valve box 40.
The on-off valve element 43 inserted in 1 is closed by the valve closing spring 44.
Closed to 2. The valve opening operation of the opening / closing valve body 43 is performed by pressing the valve opening operation tool 45 facing the valve surface of the opening / closing valve body 43 with the pressing tool 4.
It is performed by driving the pneumatic cylinder 36 through 6 to the opening / closing valve body 43 side. Further, the relief valve 38 has a valve box 40.
The relief valve chamber 48 and the relief valve seat 49 are formed in the lower part of the
0 is the pressure spring 51 for setting the relief pressure and the relief valve seat 49
Is closed to. The tension of the pressing spring 51 is adjusted by moving the spring seat 52 forward and backward with an adjusting bolt 53.

Further, as shown in the longitudinal sectional view of FIG. 4, the reservoir tank 34 has a reserve chamber 57 and a spring chamber 58 formed on the left and right of a piston 56 inserted in a reserve cylinder 55. This is a work pallet 1 with both quick joints 21
When the hydraulic pressure supply / discharge device 4 is switched from the high pressure clamp state A to the low pressure clamp state B in the state of being separated from the hydraulic pump P at the position 23, the pressure oil discharged from the low pressure clamp operation valve 14 is stored in the reserve spring 59. Against the reserve room 57
It is something that is temporarily stored inside. Then, when the work pallet 1 is connected again to the hydraulic pump P, the stored pressure oil is returned from the quick-discharging joint 23 for exhaust pressure to the oil tank 19 through the exhaust passage 18.

5 to 8 show another embodiment, and a configuration different from that of the first embodiment will be described. The members having the same functions as those in the first embodiment are designated by the same reference numerals.

(Second Embodiment) FIGS. 5 and 6 show a second embodiment. in this case,
As shown in FIG. 5, the hydraulic clamp 3 is configured as a single-acting type, and when the hydraulic pressure supply / discharge device 4 discharges the pressure oil from the clamp operating oil chamber 9, the clamp tool 8 is unclamped by the return spring 61. To be done. The hydraulic pressure supply / discharge device 4 is always connected to the hydraulic pump P.

Further, the high-pressure clamp operation valve 12 is the pressure supply on-off valve 63.
And a pressure reducing valve 20 for setting a high clamp pressure, and the unclamping operation valve 13 includes a discharge pressure opening / closing valve 64. Further, the low pressure clamp operating valve 14 is composed of a relief two-stage switching type relief valve 68. The relief two-stage switching type relief valve 68 is configured so that the relief valve body 69 can be switched between the relief state X and the relief blocking state Y by the relief lock means 70, as shown in the vertical sectional view of FIG. There is. That is, the relief valve chamber 73 and the relief valve seat 74 are formed in the valve box 72, and the relief valve body 69 inserted in the relief valve chamber 73 is used as a relief / locking pressure spring 76.
Then, the relief valve seat 74 is closed and abutted. This relief
As shown by the solid line diagram, the lock and pressure spring 76 has a large tension when the spring seat 80 is advanced toward the relief valve seat 74 via the cam 79 by the switching lever 78 of the relief lock means 70. While holding the valve element 69 in the relief blocking state Y, as shown by the two-dot chain line, when the spring seat 80 is retracted via the cam 79 by the switching lever 78, the tension is adjusted to the relief setting pressure, The relief valve body 69 is switched to the relief state X.

According to the configuration of the second embodiment, the low-pressure clamp operating valve 14 can omit the opening / closing valve, so that the valve box 72 can be small and can be made small.

(Third Embodiment) FIG. 7 shows a third embodiment, which is obtained by modifying the second embodiment as follows.

In this case, the high pressure clamp operation valve 12 is the pressure supply on-off valve 6
3 and a relief valve 22 for setting the supply pressure. Further, the low pressure clamp operation valve 14 and the unclamp operation valve 13 are integrally configured as a relief three-stage switching relief valve 88. This relief three-stage switching type relief valve 88 is
The relief valve body 89 is configured to be substantially similar to that shown in FIG. 6, and the relief valve 89 is selected by the switching lever 91 of the relief three-stage switching means 90 into the relief operating state X, the relief blocking state Y, and the relief open state Z. It is configured to be switchable.

According to the configuration of the third embodiment, the opening / closing valve can be omitted from the low pressure clamp operating valve 14, and the valve box of the unclamping operating valve 13 can be omitted. Therefore, the entire valve device can be further downsized. Thus, the hydraulic pressure supply / discharge device can be made compact.

(Fourth Embodiment) FIG. 8 shows a fourth embodiment. In this case, the three-position directional control valve device 9 is provided between the hydraulic clamp 3 and the hydraulic pump P.
4, the directional control valve device 94 operates at the pressure supply position Q.
The relief position R and the exhaust pressure position S are switchable to three positions. The high pressure clamp operating valve 12 is
The directional control valve device 94 comprises a valve body at the pressure supply position Q and a pressure supply relief valve 22, and the unclamping operation valve 13 comprises a valve body at the discharge pressure position S of the directional control valve device 94. The operation valve 14 comprises a valve element at the relief position R of the direction switching valve device 94 and the relief valve 38.

The hydraulic pressure supply / discharge device 4 of the present invention is not limited to the above-mentioned embodiments, and each type of the hydraulic clamp 3 and the configuration of each operation valve 12, 13, 14 may be appropriately combined. .

The fixed object of the hydraulic clamp 3 may be a caulking type pipe joint instead of the work W.

[Brief description of drawings]

1 to 8 show an embodiment of the present invention, FIGS. 1 to 4 show the first embodiment, FIG. 1 is an overall system diagram, FIG. 2 is an operation explanatory diagram, and FIG. 3 is FIG. 4 is a vertical sectional view of the low-pressure clamp operating valve, FIG. 4 is a vertical sectional view of the reservoir tank, and FIGS.
FIG. 5 shows a second embodiment, FIG. 5 corresponds to FIG. 1, FIG. 6 corresponds to FIG. 3, and FIG. 7 corresponds to FIG. 1 showing the third embodiment.
FIG. 8 is a view corresponding to FIG. 1 showing the fourth embodiment. 9 and 10 show a conventional example, FIG. 9 is a view corresponding to FIG. 1, and FIG. 10 is a view corresponding to FIG. 3 ... Hydraulic clamp, 9 ... Clamp hydraulic oil chamber, 12 ...
… High pressure clamp control valve, 13 …… Unclamp control valve, 14 …… Low pressure clamp control valve, 17 …… Pressure supply line,
21 ... Rapid joint for supply pressure, 23 ... Rapid joint for exhaust pressure, 3
4 ... Reservoir tank, 37 ... Open / close valve, 38 ... Relief valve, 55 ... Cylinder, 56 ... Piston, 57 ...
... reserve chamber, 59 ... reserve spring, P ₁ ... pressure for high pressure clamp, P ₂ ... pressure for low pressure clamp.

Claims (3)

[Scope of utility model registration request] 1. A high pressure clamp operating valve (12) is provided between a clamp working oil chamber (9) of a hydraulic clamp (3) and a pressure supply passage (17), and the high pressure clamping operating valve (12) is provided. To allow the pressure oil to flow from the pressure supply passage (17) to the clamp working oil chamber (9) and set the clamp working oil chamber (9) to the high pressure clamping pressure (P ₁ ). It is configured to be switchable between a valve state and a closed state in which pressure oil is prevented from flowing out, and an unclamping operation valve (13) is provided between the clamp working oil chamber (9) and the discharge passage (18). ) Is provided, and the unclamping operation valve (13) is provided with a valve closed state that prevents the pressure oil from flowing out from the clamp working oil chamber (9) to the discharge pressure passage (18), A hydraulic pressure supply / discharge device for a hydraulic clamp, which is configured to be switchable to a valve open state that allows oil to flow out, in a low pressure between the clamp working oil chamber (9) and the discharge pressure passage (18). Clamp operating valve (14) is provided in parallel with the unclamping operation valve (13), and the low pressure clamping operation valve (14) is connected from the clamp working oil chamber (9) to the exhaust pressure passage (18). When the valve is closed to prevent the pressure oil from flowing out, the pressure in the clamp working oil chamber (9) changes from the high pressure clamping pressure (P ₁ ) to the predetermined low pressure clamping pressure (P ₁ ).
A hydraulic pressure supply / discharge device capable of switching the clamping pressure of a hydraulic clamp, characterized in that it can be switched to a relief state allowing the outflow of pressure oil until it falls to ₂ ). 2. The hydraulic pressure supply / discharge device capable of switching the clamping pressure of the hydraulic clamp according to claim 1, wherein the low-pressure clamping operation valve (14) is connected in series to an opening / closing valve (37) and a relief valve. (38) A hydraulic pressure supply / discharge device capable of switching the clamping pressure of the hydraulic clamp, which is constituted by (38). 3. A hydraulic pressure supply / discharge device capable of switching the clamping pressure of the hydraulic clamp according to claim 1 or 2, wherein a rapid pressure supply joint (21) is provided at an upstream portion of the pressure supply passage (17). A quick release joint (23) for exhaust pressure is provided in the downstream portion of the exhaust passage (18), and the quick joint (23) for exhaust pressure and the operating valve for the low pressure clamp are provided.
A reservoir tank (34) for receiving the pressure oil flowing out from the clamp hydraulic oil chamber (9) through the low pressure clamp operation valve (14) is provided between the reservoir tank (34) and the reservoir tank (34). ) Is formed between the cylinder (55), the piston (56) oil-tightly inserted into the cylinder (55), and one end wall of the cylinder (55) and the piston (56). A reserve chamber (57) for containing pressure oil and a reserve spring for elastically pressing the piston (56) toward the one end wall.
(59) A hydraulic pressure supply / discharge device capable of switching the clamping pressure of the hydraulic clamp, which is configured by (59).