JPH0241836A - Fluid pressure clamp device with intensifying circuit - Google Patents

Abstract

PURPOSE:To cost down a hydraulic instrument and to reduce the consumption power by forming the structure of clamping by feeding a low initial pressure to a clamping cylinder and obtaining the specified clamping power by feeding the pressure higher than the initial pressure simultaneously with the clamp. CONSTITUTION:A low initial pressure is fed via a three way solenoid change- over valve 13 to a clamping cylinder 8, clamping is performed by moving a piston 7, a clamp circuit is cut off by a check valve 15 with a pilot simultaneously with clamping and the surge pressure generated at clamping time is sealed in the circuit. The structure is formed at the same time so as to obtain a specified clamping power by feeding the pressure higher than the initial pressure by intensifying pistons 38, 39 and to operate alternately the intensifying pistons 38, 39 by having a duplicate time by providing them in parallel. Consequently, the need for setting the hydraulic circuit of the whole machine in a high pressure with the clamp power as the reference is eliminated and the cost down of a hydraulic instrument and the reduction in the consumption of the hydraulic driving power can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improved fluid pressure clamping device with a pressure booster circuit used in machine tools and the like.

BACKGROUND OF THE INVENTION Conventionally, the setting value of the source pressure of a fluid pressure circuit including a clamp circuit is set based on a relatively high pressure to be supplied to a lamp cylinder because it is powerful and requires a large lamp force.

Problems to be Solved by the Invention In the fluid pressure circuit set to high pressure as described in the prior art, a high output and expensive fluid pressure source is required, and accompanying this, equipment that can withstand the high pressure for the entire circuit is required. and piping. Further, high pressure pump units have problems such as high power consumption and the need to provide pressure reducing valves at locations where low pressure is required.

The present invention has been made in view of these problems of the prior art, and its purpose is to provide a fluid pressure clamping device with a pressure increasing circuit in addition to a clamping cylinder by increasing the source pressure. It is something to do.

Means for Solving the Problems In order to achieve the above object, the fluid pressure clamping device with a pressure booster circuit according to the present invention includes a 3-position electromagnetic switching valve that switches the source pressure supplied to the clamping cylinder, and a 3-position electromagnetic switching valve that switches the source pressure supplied to the clamping cylinder. A check valve that closes the source pressure supply circuit when the electromagnetic switching valve operates, an electromagnetic switching valve that operates in response to the clamp signal, and a pressure booster piston member that operates the electromagnetic switching valve to supply a pressure higher than the source pressure. It includes the following.

Further, at least two sets of electromagnetic switching valves and pressure increasing piston members are provided in parallel, each pressure increasing piston member is provided with piston movement detecting means, and the electromagnetic switching valves are alternately switched by a signal from the movement detecting means. It is also possible to connect them and apply pressure continuously.

When the original pressure is sent from the hydraulic source to the working clamp cylinder and clamping is performed, a clamp 6'lI L'l signal is output from the detector. This signal switches the 3-position solenoid switching valve to the neutral position, and the check valve with pilot shuts off the supply circuit and seals the surge pressure generated during clamping into the circuit.At the same time, the solenoid valve for one of the pressure booster pistons The original pressure is sent to one of the pressure increasing piston members, and the pressure increased by the pistons having different area ratios is applied to the clamping cylinder to generate a predetermined clamping force. If there is a leak in the fluid pressure circuit system during clamping due to damage to the packing, etc., a signal is output by the detection means before the piston of one pressure booster piston moves and reaches the end of movement, and this signal The other electromagnetic switching valve is immediately switched, the other pressure increasing piston member starts operating, and increased pressure is applied to the clamping cylinder.
The timer switches the electromagnetic switching valve that lags behind the output signal of the detection means, one pressure-increasing piston member stops operating, and the piston returns to the starting position and waits.

Embodiment An embodiment will be described with reference to the drawings. Figures 1 and 2
In the figure, a turning shaft 1 is provided on a tool rest for a lathe so as to be rotatable and movable in the axial direction. A turret 2 is fitted to the tip of the rotating shaft 1, and a gear 3 is fitted to the rear end, and the gear 3 meshes with a gear 5 fitted to the output shaft of a motor 4 fixed to the tool rest. Rotation indexing of the rotation axis 1 is performed under NC control. The turret 2 and the turret have a pair of crown-forming forces,
One side of each pulling 6 is fixed, and the pivot axis l
The piston 7 is fitted into a cylinder 8 provided on the tool post, and the pressure oil is switched by a hydraulic system, which will be described later, to move the turret 2 in the axial direction via the rotation axis l. Clamping is performed during disconnection and attachment,
A clamp confirmation signal is output by the glue switch LSI stuck to the tool rest.

In the hydraulic circuit supplied to the cylinder 8, the hydraulic pressure a11 supplying the source pressure PS is supplied to the three-position electromagnetic switching valve 1 through a pipe line 12.
The boat b of the solenoid valve 13 is connected to the conduit 14. Check valve with pilot 15. It communicates with the right chamber of the cylinder 8 via a conduit 16. Further, the boat C of the T4 magnetic valve 13 is communicated with the left chamber of the cylinder 8 via a pipe 17, and the boat d of the switching valve 13 is communicated with the inside of the hydraulic tank via a pipe 20.

Furthermore, the hydraulic pressure #11 is communicated with the boat e of the two-position electromagnetic switching valve 24 of the pressure booster circuit 23 via a conduit 21, and the boat f of the two-position electromagnetic switching valve 25 via a conduit 22. Further, the boat g of the switching valve 24 is connected to the right chamber of the pressure increasing cylinder 27 via the conduit 26, and the boat h is connected to the right chamber of the pressure increasing cylinder 27 through the conduit 28. The check valve 29 communicates with the left chamber of the cylinder 27 via a conduit 30. The boat 1 of the switching valve 25 is connected to the right chamber of the cylinder 32 via the pipe 31, and the boat J is connected to the pipe 33, the valve 34. Pressure increasing cylinder 3 via pipe line 35
It communicates with the left ventricle of 2. Also, the boat k of the solenoid valve 24
and the boat l of the solenoid valve 25 are communicated via lines 36, 37 into the hydraulic tank.

The pistons 38 and 39 fitted into the cylinders 27 and 32 are both formed such that the area (AI) of the right end surfaces 38a and 39a is larger than the area (A2) of the left end surfaces 38b and 39b, so that the source pressure PS of the cylinders 27. 32 and presses the piston 3839, an increased pressure PB equal to the original pressure PS multiplied by the piston area ratio (Al/A2) is generated in the left chamber of the cylinder. .

The left chamber of the cylinder 27 is communicated with a conduit 42 via a conduit 40 and a check valve 41 that branch from the conduit 30 midway, and the left chamber of the cylinder 32 communicates with a conduit 43 and a check valve that diverge from the conduit 35 midway. 44, and the pipe 42 communicates with the right chamber of the cylinder 8 via a pipe 45.

Further, magnetic dogs 47, 48 are embedded in the outer peripheries of the pistons 38, 39, respectively, and contactless reed switches LS2. LS3, and a non-contact type reed switch LS4. LS5 is provided. The reed switches LS2 and LS4 are adjusted so that the piston 38.39 moves to the left and outputs a signal just before reaching the left end, and the reed switches LS3 and LS5 are adjusted to output a signal when the piston 38.39 moves to the right. A signal is output when the right end is reached.

Next, the operation of the hydraulic clamp device with a pressure increase circuit according to the present invention will be explained.

When the turret 2 is rotated and the indexing is completed, the solenoid SQL 2 is energized by the indexing completion signal, the solenoid valve 13 is switched to the ■ position, and the boats a and b are connected to supply oil from the hydraulic source 11 to the pipe line 12. The source pressure PS is sent to the pilot check valve 15 via the pipe line 14. The pressure oil that has passed through the bi-lofted check valve 15 is sent to the right chamber of the cylinder 8 through the pipe 16, and the piston 7 moves, and the turret 2 moves toward the tool post via the pivot axis l, and is connected to the crown-shaped coupling. 6 engages. Immediately before the coupling engages, a signal is output from the limit switch LSI, and this signal switches the switching valve 13 to the neutral position ■, communicating with the boats d and c, and connecting the check valve 1 with biloft.
5 is closed, the pipe line 16 is closed, and a surge pressure of approximately 1.5 to 3 times the original pressure PS generated at the time of clamping is contained within the circuit.

Note that the detector for checking the clamp is not limited to a limit switch; for example, a piezoelectric element may be embedded in the coupling 6 to directly detect the clamp pressure.

At the same time, the solenoid 5OL2 is de-energized, the solenoid 5OL3 is energized, the switching valve 24 is switched, the boat e is communicated with the port g, and the source pressure PS is sent to the right chamber of the cylinder 27 through the conduit 26. Push the piston 38 to the left. This pressure generates a pressure PB in the left chamber of the cylinder 27 that is increased by the piston area ratio, and this increased pressure PB is blocked by the check valve 15 with pilot and the check valves 29 and 34 and through the check valve 41 in the recirculation direction, and the pipe 42.45.1.
6 and is applied to the right chamber of the cylinder 8 to pressurize the piston 8 and generate a predetermined clamping force.

For example, a cylinder is inserted into the circuit during clamp operation.

If there is a leak due to a scratch on the piston or the like, the piston 38 will gradually move to the left. When the piston 38 moves to just before the left end, the dog 47 approaches and the reed switch LS
2 outputs a signal. This signal immediately causes the solenoid SQ to
L4 is energized to switch the switching valve 25, the boats r and i communicate with each other, and the source pressure PS is sent to the right chamber of the cylinder 32 through the pipe 31, pushing the piston 39 to the left. The increased pressure PB is then applied to the pipe 43. Check valve 44.
It is added in duplicate to the right chamber of cylinder 8 via lines 42, 45, 16. The timer starts operating at the same time with the signal from reed switch LS2, and after a delay of about 0.05 to 0.1 seconds, solenoid 5OL3 is de-energized, switching valve 24 is switched, boats e and h are communicated, and pressure oil is transferred to the pipe. 28. Check valve 29. It is supplied to the left chamber of the cylinder 27 through the conduit 30, the piston 38 is shifted to the right, moves to the right end position at the start, and waits, and a standby signal is output from the reed switch LS3. Thus, the pistons 38, 39 are connected to the reed switch LS2, as shown in FIG. Since the operation is switched alternately with overlapping time by the signal of LS4, there is no interruption of the clamping force.

Next, when aso-clamping is performed, the solenoid 5OLI is energized, the switching valve 13 is switched to the ■ position, ports a and C are communicated, the source pressure PS is supplied to the left chamber of the cylinder 8, and the piston 7 moves to the right. to release the clamp. At the same time, switching valves 24 and 25 are both set to non-J'Et, ports e and h and ports f and j are communicated with each other, and cylinders 27 and 25 are set to non-J'Et. [The original pressure PS is supplied to the left chamber of No. 2, and the pistons 38 and 39 move to the right,
Wait at the rightmost position.

The cracking pressure of the lock valves 41 and 44 is set higher than the original pressure so that the original pressure PS supplied to the left chamber of the cylinder 27 and 32 does not leak during unclamping.

Effects Since the present invention is configured as described above, it produces the following effects.

Supplying low source pressure to the clamping cylinder and moving the piston to perform clamping, and at the same time as clamping, shut off the clamp circuit with a check valve with a pilot, seal the surge pressure generated during clamping in the circuit, and increase the pressure at the same time. A piston member supplies pressure higher than the original pressure to the clamping cylinder to obtain a predetermined clamping force, and furthermore, pressure increasing piston members are set in parallel and operated alternately with overlapping time. Therefore, there is no need to set the hydraulic circuit of the entire machine to a high pressure based on the clamping force, which reduces the cost of hydraulic equipment, reduces the consumption of hydraulic drive power, and reduces power loss, which reduces heat generation in the hydraulic unit. This reduces the deterioration of machine accuracy due to thermal displacement.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of the present invention showing a state in which the pressure booster circuit starts to operate after clamping, and FIG. 2 is a diagram illustrating the discharge timing of the pressure booster circuit. 8... Clamp cylinder 13... 3 position solenoid switching valve 15... Check valve with pilot 24.25... Solenoid switching valve 27.32... Pressure increase cylinder 38.39... Pressure increase piston

Claims (1)

[Claims] (1) A 3-position electromagnetic switching valve (13) that switches the source pressure supplied to the clamp cylinder (8), and a source pressure supply circuit (16) that operates when the clamp signal operates the 3-position electromagnetic switching valve (13).
), an electromagnetic switching valve operated by the clamp signal, and a pressure increasing piston member that operates to supply a pressure (PB) higher than the source pressure (PS). 1. A fluid pressure clamping device with a pressure increase circuit, characterized in that the pressure is applied to a clamping cylinder at a pressure higher than the original pressure during clamping.