JPH02256437A - Clamp operating circuit - Google Patents

Abstract

PURPOSE:To improve operability for changing the operation of a working cylinder and also to simplify an entire device by providing a detecting cylinder for detecting the operation of the working cylinder and providing respectively original position reset compensating means. CONSTITUTION:A detecting cylinder 5 for indirectly detecting the moving position of the piston 1a of a working cylinder 1 according to the quantity of movement of a piston 5a moving proportionally to the flow rate of oil passing through a fluid circuit X is provided between a rotary joint 4 and a hydraulic power supply source Q. Check valves 11, 12 as original position reset compensating means are arranged in parallel to the working cylinder 1 and the detecting cylinder 5. When the detecting cylinder reaches to the original position, the check valve 12 is opened, oil is supplied to pressure chamber 3 and the piston 1a is moved to an unclamping direction. When the working cylinder 1 is previously reset and stopped in its original position the check valve 11 is opened and the oil is continuously supplied to a pressure chamber 10 until the detecting cylinder 5 completely reaches to its original position.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a clamp operation circuit for operating a work clamp operation cylinder provided on a workpiece mounting jig.

[Prior art and its problems] Conventionally, as shown in FIG. 5, for example, a plurality of actuation cylinders C for clamping the workpiece are provided on a workpiece mounting jig, and in a clamp actuation circuit for actuating the actuation cylinders C. , the operating cylinder C was controlled by each position detector S provided at the operating site, and a fluid drive circuit X consisting of a fluid supply source q, a direction switching valve v, and the like.

However, the above-mentioned position detector S must be installed by adjusting a dog or a switch for each detection position. Systems with many processing stations, such as machines, require a large number of dogs or switches and are therefore expensive.

Furthermore, in the case of an index type workpiece mounting jig that rotates with respect to a fixed part, or in a place where the clamp operation part is crowded with various devices from a fluid supply source, a large number of dogs or switches making up the above-mentioned detector S may be used. must be installed and wired near moving parts or remote operating parts, which not only poses problems in terms of installation space, but also
Hydraulic piping, electrical wiring, etc. were complicated, causing problems in assembly and maintenance.

For example, when processing several types of workpieces W of different sizes using a single clamping device, it is necessary to change the mounting position of the actuating cylinder C according to the height and width of the workpieces W, or to There is a problem in that the setup change work such as changing the control device of the operating cylinder is extremely troublesome, requires a lot of time and effort, and the work efficiency is extremely low.

[Object of the Invention] The present invention was devised by paying attention to the conventional problems, and its purpose is to control the operation of, for example, a plurality of actuating cylinders for work clamping by controlling the flow of fluid to the actuating cylinders. It is configured so that it can be reliably detected and controlled by a cylinder for detecting the operating flow rate installed at an appropriate location in the circuit, and depending on the type of workpiece, many switches and complicated electrical wiring may be installed on the workpiece mounting jig. Therefore, the present invention provides a clamp operating circuit which can improve the operability of changing the operation of the operating cylinder, simplify the entire device, and facilitate maintenance.

[Structure of the Invention] In order to achieve the above object, the present invention provides a method for detecting the operation of the working cylinder in a fluid circuit connecting the working cylinder for work clamping provided near the work and a fluid supply source. The gist of the present invention is to provide detection cylinders, and to provide return-to-home position compensation means corresponding to each of the cylinders.

[Function] As a result, the present invention detects the movement of the actuating cylinder using a detection cylinder separate from this cylinder, so the clamping movement can be detected at a position away from the actuating cylinder that is easy to work with. In addition to easy setup changes such as position changes, the provision of a home position return compensation means allows both cylinders to be reliably returned to their home positions when unclamping, and the operating reference position and detection reference position are established. Therefore, the operation of the operating cylinder can be detected reliably and well, and malfunctions will not occur.

[Example] Hereinafter, the present invention will be explained in detail based on the drawings.

1 and 2 illustrate one embodiment of the clamp actuation circuit of the present invention.

Reference numeral 1 denotes an operating cylinder for one or more workpiece clamps, which is installed on a workpiece mounting jig (not shown) rotatably attached to a fixed part such as a bed. The two pressure chambers 2.3 defined by the piston 1a of the working cylinder 1 are connected to a fluid circuit X that is connected to a hydraulic pressure source Q that supplies oil as working fluid. This fluid circuit X has a rotary joint 4 interposed at a connecting portion between the fixed part side piping and the movable part side piping.

The fluid circuit X is also provided with a detection cylinder 5 that detects the operation of the actuation cylinder 1. This detection cylinder 5 is connected between the rotary joint 4 and the hydraulic pressure supply source Q. This detection cylinder 5 is
The operation of the working cylinder 1, that is, the moving position of the piston 1a, is indirectly detected by the amount of movement of the piston 5a, which moves in proportion to the flow rate of oil flowing through the fluid port 1i8x.

A dog 6 provided on the piston rod 5blfJFi of the detection cylinder 5 and a plurality of limit switches S1, S2, S'
2, . . . S3 form a position detection means 7.

Of these, the limit switch S] is in the Angular position, which is the original position of the operating cylinder l, and the limit switch S2
, S'2, . . . are clamp completion positions corresponding to multiple types of workpieces W1, W2, . They are arranged to correspond to each other.

In Figure 1, both cylinders 1.5 are at the backward limit! The case is shown in a certain unclamp position, that is, in the original position.

In the fluid circuit
0. At this time, the detection cylinder 5 moves to the right and stops.

At the same time, the oil in the pressure chamber 9 on the opposite side is pushed out and reaches one pressure chamber 3 of the working cylinder 5 via the rotary joint 4 and the throttle 18, causing the piston 1a to move backward in the unclamping direction.

Then, the piston 1a reaches the retraction limit of the operating cylinder 1, that is, the original position, the piston 5a of the detection cylinder 5 also reaches the retraction limit, that is, the original position, and the dog 6 presses the limit switch S1 to detect the unclamp position. .

On the other hand, move the actuating cylinder 1 in the clamping direction (arrow direction in the figure).
When the oil is operated at the source Q, as shown in Fig.
from the operating cylinder 1 via the electromagnetic switching valve 8 and the rotary joint 4.
is supplied to the other pressure chamber 2, and moves the piston 1a forward in the clamping direction. At the same time, the oil in the pressure chamber 3 on the opposite side is pushed out, flows into the pressure chamber 9 on the right side of the detection cylinder 5 via the throttle valve 18 and the rotary joint 4, and moves the piston 5a in the clamp detection direction (left direction in the figure). ).

Then, the piston rod 1b of the actuating cylinder 1 contacts the workpiece W1 and clamps it at a predetermined pressure, and at the same time, the dog 6 of the detection cylinder 5 presses the limit switch S2 to detect the clamping completion position.

However, if there is no workpiece on the jig, for example, the piston 1a of the operating cylinder 1 moves further to the forward limit, and as a result, the piston 5a of the detection cylinder 5
The dog 6 also moves to its forward limit, and the dog 6 presses the limit switch S3 to detect the overstroke position.

In this way, the detection means 7 is provided at a position where it is easy to work on the stationary side. Therefore, even if multiple types of workpieces W1, W2, W3, etc. of different sizes are handled by the same clamping device, there is no need to provide many switches or their wiring on the movable mounting jig. , by providing the detection switches S2, S2, S2, . . . on the detection cylinder 5 side in the number of corresponding workpieces, and there is no need to change the stage according to the type of workpiece.

In such a fluid circuit X, if oil leaks in the cylinder or circuit, for example, one of them will not completely return to its original position when unclamping or when starting use. In order to prevent this, check valves 11 and 12 are provided in parallel with the operating cylinder 1 and the detection cylinder 5 as return-to-home compensation means.

That is, in order to operate both cylinders 1.5 in the unclamping direction from the clamped state, when oil is supplied from the supply source Q to the pressure chamber 10 of the detection cylinder 5, the piston 5a of the detection cylinder 5 moves as described above. To the right, the piston 1a of the working cylinder 1 is moved backward in the unclamping direction.

At this time, if the detection cylinder 5 does not reach the home position before the working cylinder 1 for some reason, the working cylinder 1 will stop before reaching the home position unless the check valve 12 is provided. Therefore, even though the actuating cylinder 1 has not retreated to the original position of the unclamping position, the detection cylinder 5 and switch S1 generate an erroneous signal indicating that unclamping is complete.

Therefore, in the fluid circuit X shown in FIG.
2, when the detection cylinder 5 reaches the original position, when further oil is supplied, the oil pressure in the left pressure chamber 10 exceeds the cracking pressure of the check valve 12, and the check valve 12 is opened. .

As a result, oil is supplied from the supply source Q to the check valve 12, the rotary joint 4, the throttle 18, and the pressure chamber 8, and the piston 1a moves in the unclamping direction. As the piston 1a moves, oil in the pressure chamber 2 flows into the tank T via the rotary joint 4 and the electromagnetic switching valve 8.

Therefore, even though the detection cylinder 5 has stopped at the right end first, the oil passes through this check valve 12 and continues to flow through the operating cylinder 1 until the operating cylinder 1 completely returns to its original position (unclamping position). continues to be supplied to the pressure chamber 3.

When the operating cylinder 1 returns to its original position and stops, the oil pressure in the pressure chamber 3 increases and exceeds the cracking pressure of the check valve 11, and the supply source Q supplies the check valve 12, throttle 13,
An oil passage is formed from the rotary joint 4 to the check valve 11 to the tank T, and oil continues to flow by the amount set by the throttle 13.

Therefore, both cylinders 1.5 always return to their original positions when unclamped and continue to maintain that position.

On the other hand, if the operating cylinder 1 returns to the original position before the detection cylinder 5 when unclamping from clamping, the detection cylinder 5 will not reach the original position unless the check valve 11 is provided. It stops midway and the unclamping position of the working cylinder 1 cannot be detected by the switch S1.

Therefore, by providing the above-mentioned check valve 11 in this fluid circuit The hydraulic pressure inside exceeds the cracking pressure of the check valve 11, and the check valve 11 is opened.

As a result, from the supply source Q, the pressure chamber 10 and the pressure chamber 9,
Rotary joint 4, check valve 11, throttle 13, rotary joint 4,
An oil passage is formed from the electromagnetic switching valve 8 to the tank T, and oil is continuously supplied to the pressure chamber 10 of the detection cylinder 5 until the detection cylinder 5 completely reaches its original position.

When the detection cylinder 5 reaches its original position and stops, the oil pressure in the left pressure chamber 10 exceeds the cracking pressure of the check valve 12, and the check valve 12 is opened. As a result, an oil path is formed from the supply source Q to the check valve 12, the rotary joint 4, the check valve 11, the throttle 13, the rotary joint 4, the electromagnetic switching valve 8, and the tank T, and the oil continues to flow in small amounts along this path. . Therefore, in this case as well, both cylinders are 1.5
always returns to its original position and continues to hold that position.

Furthermore, if the detection cylinder 5 is installed in the supply side flow path to the working cylinder 1 during unclamping, in the clamped state shown in FIG. In this state, the oil passage from the pressure chamber 3 of the operating cylinder 1 to the detection cylinder 5 is always maintained at a low pressure sufficient to overcome the frictional resistance of the cylinder, etc., and high pressure is not generated. It is extremely rare for leaks to occur in the pipe line or rotary joint 4 that connects the cylinder 1 and the detection cylinder 5.
There is very little risk that the cylinder 5 for detecting during clamping will move due to leakage, and the machining operation will not be interrupted unnecessarily.

On the other hand, if the piston 1a of the operating cylinder 1 starts to move for some reason during clamping and the clamp is released, at the same time, the piston 5a of the detection cylinder 5
movement, the clamp detection is released, and an abnormality is detected.

Furthermore, by providing the check valves 11 and 12,
The oil passage connecting the working cylinder 1 and the detection cylinder 5 is not completely shielded from the working fluid therein, and upon completion of the unclamping operation, an oil passage passing through the check valves 11 and 12 is formed. Therefore, there is no problem of rotting of the working fluid, such as oil, in the piping.

[Modifications] As another embodiment of the present invention, a fluid circuit X' as shown in FIG. 3 is also conceivable.

This is because, in circuit X of FIG. 1, if the movement of the piston 5a of the detection cylinder 5 becomes slow due to temperature changes or other causes, the piston 5a will not move unless the operating pressure is higher than the cracking pressure of the check valve 12. As a countermeasure against such a situation, a sequence valve 14 is provided in the original position return compensating means on the detection cylinder 5 side instead of using the check valve 12 described above. By adjusting the opening/closing operating pressure of this sequence valve 13, the normal operation of the detection cylinder 5 can be compensated.

Note that other parts are the same as those in the embodiment shown in FIGS. 1 and 2, so the same parts are denoted by the same reference numerals and the explanation thereof will be omitted.

In addition to connecting the check valve 11 on the working cylinder 1 side as shown in FIGS. 1 to 3, for example, as shown in FIG. 15, where the check valve 1 is installed.
By connecting the input side of piston 1, for example, during unclamping operation, when the piston 1a retreats, the check valve 11 is opened a little before returning to the original position.

For example, if the piston 1a gets stuck and stops for some reason during retraction, the pressure inside the pressure chamber 3 increases and if the check valve 11 opens at that point, the check valve 11, the throttle 13 Since an oil path is formed through which oil flows out to the tank, oil is continuously supplied to the pressure chamber 10 of the detection cylinder 5. This results in
This results in an erroneous detection in which the detection cylinder 5 detects unclamping even though the operating cylinder 1 has not reached the unclamping position.

Therefore, by connecting the check valve 11 as shown in FIG. 4, the check valve 11 is opened when the piston 1a crosses the boat 15 during retraction, so that in the unlikely event that the piston 1a
Even if an abnormal situation occurs in which the check valve 11 stops midway, the check valve 11 will not open at that point and the detection cylinder 5 will stop at the same time, so that erroneous detection will not be performed.

Incidentally, only one actuating cylinder 1 is shown in the 3rd Kokuto and Fig. 4, but as shown in Figs. 1 and 2, a plurality of actuating cylinders 1 are provided depending on the clamping method. Good too.

[Effects of the Invention] According to the present invention, the operation of the actuating cylinder for work clamping can be indirectly detected, for example, by the detection cylinder provided at a position away from the actuating cylinder where work can be easily performed. Even in a device consisting of cylinders, only one detection cylinder is required, the configuration of the entire clamp operation circuit is not complicated, and operability is improved.

In addition, it is only necessary to provide a detection means such as a limit switch or a dog and electrical wiring corresponding to the detection cylinder, and there is no need to provide a detection means for each operating cylinder on the movable side or at a remote location, so the device can be easily installed. It does not become complicated, does not make hydraulic piping or electrical wiring complicated, and is easy to install in the installation space and piping.
No more electrical wiring problems.

Furthermore, even if the operating position of the operating cylinder increases, the number of limit switches can be increased to accommodate the detection cylinder.
In addition, it can be easily handled by adjusting the position, and setup changes can be easily performed, and since the detection is based on the flow rate of the working fluid flowing through the circuit, reliable operation detection can be expected.

Furthermore, since the configuration is simple, it can be manufactured at low cost and maintenance is easy.

In particular, since return-to-home compensation means are provided for each of the operating cylinder and the detection cylinder, even if one of the two cylinders reaches the home position first during unclamping, each cylinder will return to its home position at that time. The compensating means operates to ensure that both cylinders return to their original positions, and the operating reference position and detection reference position are reliably determined, thereby eliminating erroneous detection and malfunction based thereon.
4゜In addition, by installing the above-mentioned detection cylinder in the flow path on the working fluid supply side during unclamping operation, as long as the working cylinder maintains the clamped state during processing, leakage at the rotary joint can be prevented. The occurrence of this is extremely rare, and the eight clamp detection states are maintained without movement of the piston of the detection cylinder, eliminating problems such as unnecessary interruption of machining operations.

Furthermore, by activating the return-to-origin compensation means on the working cylinder side during unclamping operation, just before the piston of the working cylinder returns to its original position, for example, if the working cylinder gets stuck in the middle and stops. When the sensor has stopped, the return-to-origin compensating means is not activated and the detection cylinder is also stopped at the same time, so that erroneous detection is not performed and malfunctions can be prevented.

In this way, the detection cylinder always correctly detects the movement of the operating cylinder, and accurate control is performed.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the clamp operation circuit of the present invention and shows an unclamp test a, FIG. 2 is a circuit diagram showing the same clamped state, and FIG. 3 is a circuit diagram showing another embodiment. FIG. 4 is a circuit diagram of a main part showing another example of the check valve piping method, and FIG. 5 is a diagram showing a conventional clamp operation circuit. 1... Working cylinder, 2.3... Pressure chamber, 4...
Rotary joint, 5... Detection cylinder, 9.10... Pressure chamber, 11.12... Check valve as home position return compensation means, 14... Sequence valve as home position return compensation means, Q...Fluid supply source, T...Tank, x,
x'...Fluid circuit. Patent Applicant: Nippei Toyama Co., Ltd. Figure 4 Diagram Procedures... Author (spontaneous) Director General of the Patent Office Yoshi 1) Tsuyoshi Moon 1, Indication of Case 1999 Patent Application No. 77525 3,
Relationship with the case of the person making the amendment

Claims (3)

[Claims] (1) In a clamp operation circuit that uses a working fluid to perform clamping and unclamping operations on a workpiece clamping working cylinder provided on a workpiece mounting jig, a detection cylinder is provided in this circuit to detect the movement of the working cylinder. In addition, a clamp operating circuit characterized in that home position return compensation means are provided corresponding to the operating cylinder and the detection cylinder, respectively. (2) The clamp operating circuit according to claim 1, wherein the detection cylinder is provided in a flow path on the fluid supply side to the operating cylinder during unclamping operation. (3) The clamp operation circuit according to claim 1 or 2, characterized in that the means for returning to the original position on the operating cylinder side is provided so as to operate at a point slightly before the operating cylinder returns to the original position during the unclamping operation. .