JP2860109B2 - Clamp operation circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clamp operating circuit for operating a work clamp operating cylinder provided on a work mounting jig.

[Prior art and its problems] Conventionally, as shown in FIG. 5, for example, a plurality of working cylinders c for work clamping are provided on a work mounting jig, and in a clamp operating circuit for operating the working cylinder c, The working cylinder c is controlled by each position detector s provided in the working part and a fluid driving circuit x including a fluid supply source q, a direction switching valve v and the like.

However, the position detector s must be provided by adjusting the dog or the switch for each operation cylinder c and for each detection position, and if they are mounted according to the number of the operation cylinders c, the FMS or transfer Systems with many processing stations, such as machines, require a large number of dogs or switches, which is expensive.

Further, in the case of an index type in which the work mounting jig rotates with respect to the fixed portion, or in a place where the clamp operation site is complicated by various devices from the fluid supply source, a large number of dogs or switches constituting the detector s are provided. Must be installed and wired near a movable part or a remote operating part, not only is there a problem with installation space, but also hydraulic piping and electrical wiring are complicated, and there are problems with its assembly and maintenance. there were.

Also, for example, when several types of workpieces w having different sizes are to be processed using a single clamping device,
Changeover work such as changing the mounting position of the working cylinder c according to the height and width of the work w, and changing the control device of a plurality of working cylinders is extremely troublesome, and requires a lot of time and labor for the changeover work. In short, there was a problem that the working efficiency was extremely poor.

[Object of the Invention] The present invention has been devised in view of the conventional problems described above, and an object of the present invention is to control the operation of, for example, a plurality of working cylinders for work clamping by using a fluid to the working cylinder. It is configured so that it can be reliably detected and controlled by the working flow rate detection cylinder provided in the appropriate place in the circuit,
According to the type of work, there is no need to provide many switches and complicated electrical wiring on the work mounting jig, and the operability of changing the operation of the working cylinder is improved. The present invention provides a clamp operation circuit that has improved the above.

[Constitution of the Invention] In order to achieve the above object, the present invention is to detect the operation of the working cylinder in a fluid circuit connecting a working clamp working cylinder provided on the side close to the work and a fluid supply source. And the original position return compensating means is provided corresponding to each of the cylinders.

[Operation] According to the present invention, the movement of the working cylinder is detected by a detection cylinder different from the cylinder, so that the clamp operation can be detected at a position that is easy to work away from the working cylinder. In addition to making it easy to change the position, such as changing the position, and providing the original position return compensation means, both cylinders can be reliably returned to their original positions during unclamping, and the operation reference position and detection reference position are determined. Therefore, the operation of the working cylinder can be reliably and satisfactorily detected, and no malfunction occurs.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

1 and 2 show one embodiment of the clamp operation circuit of the present invention.

Reference numeral 1 denotes one or more work cylinders for work clamps, which are installed on a work mounting jig (not shown) rotatably mounted on a fixed portion such as a bed. A fluid circuit connected to a hydraulic pressure source Q as a working fluid supply source that is provided on the fixed portion side and supplies oil serving as a working fluid is provided in two pressure chambers 2, 3 defined by a piston 1a of the working cylinder 1. X is connected. In the fluid circuit X, a rotary joint 4 is interposed at a connecting portion between the fixed part side pipe and the movable part side pipe.

The fluid circuit X is provided with a detection cylinder 5 for detecting the operation of the working cylinder 1 on the fixed portion side. The detection cylinder 5 has two pressure chambers 9 and 10 via a piston 5a and has a position detecting means 7 for detecting the position of the piston 5a.

The fluid circuit X connects the first flow path L1 connected to the hydraulic fluid supply source Q during the unclamping operation to one pressure chamber 10 of the detection cylinder 5 and the other of the detection cylinder 5 The pressure chamber 9 is connected to the unclamping pressure chamber 3 of the working cylinder 1 through a second flow path L2, and the third flow path connected to the hydraulic pressure source Q during the clamping operation.
L3 is connected to the clamp-side pressure chamber 2 of the working cylinder 1. Further, the fluid circuit X has a first
Between the first flow path L1 and the second flow path L2 when the pressure inside the first flow path L1 exceeds a predetermined pressure.
A check valve 12 is provided as first in-situ return compensation means for flowing oil to the inside of the second flow path L2 between the second flow path L2 and the third flow path L3. A check valve 11 is provided as second home position return compensating means for causing oil to flow from the second flow path L2 to the third flow path L3 at the time.

That is, the rotary joint 4 is connected to the second flow path L2 and the third flow path L2.
Between the movable side and the fixed side regardless of the rotation of the movable side mounting jig.
2 and L3 communicate with each other.

The fluid circuit X allows the detection cylinder 5 to indirectly determine the operation of the working cylinder 1, that is, the movement position of the piston 1a, by the movement amount of the piston 5a moving in proportion to the flow rate of the oil flowing through the fluid circuit X. Is to be detected.

Limit switches _{S 1, S 2, S '} 2 dog 6 provided in the piston rod 5b outer ends and a plurality of the detection cylinder 5, _... detecting means 7 is formed position by the S _3.

Among these, the limit switch S ₁ is an unclamping position which is the original position of the working cylinder 1, the limit switch S ₂ ,
S _'2, ..., a plurality of types of workpieces W _1, W ₂ of different sizes of the working cylinder 1, clamp completion position corresponding to ..., and the limit switch S ₃ are respectively correspond to the overstroke position of the actuating cylinder 1 It is provided to be.

FIG. 1 shows a case where both cylinders 1 and 5 are at an unclamping position which is a retreat limit, that is, an original position.

In the fluid circuit X in this state, oil is supplied from the supply source Q to the pressure chamber 10 of the detection cylinder 5 from the flow path L1 via the check valve 16, the relief valve 17, and the electromagnetic switching valve 8 as a direction switching valve. You. At this time, the detection cylinder 5
Move to the right and stop.

At the same time, the oil in the opposite pressure chamber 9 is pushed out,
One pressure chamber 3 of the working cylinder 5 through the throttle 18 from L2
And the piston 1a is moved backward in the unclamping direction.

Then, the piston 1a has reached the retreat limit i.e. the original position of the actuating cylinder 1, a piston 5a of the detection cylinder 5 also reaches the backward limit i.e. situ the dog 6 detects the unclamping position by pressing the limit switch S ₁ I do.

On the other hand, when operating the working cylinder 1 in the clamping direction (the direction of the arrow in the figure), oil is supplied from the supply source Q to the other side of the working cylinder 1 through the flow path L3 via the electromagnetic switching valve 8 as shown in FIG. The pressure is supplied to the pressure chamber 2, and the piston 1a is advanced in the clamp 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 from the flow path L2 via the throttle valve 18, and clamps the piston 5a in the clamp detection direction (left direction in the figure). ).

The piston rod 1b of the working cylinder 1 is
At the same time the W ₁ clamped in contact predetermined pressure, the dog 6 of the detection cylinder 5 detects the clamping completion position by pressing the limit switch S _2.

However, for example, when there is no work on the jig, the piston 1a of the working cylinder 1 further moves to the forward limit, whereby the piston 5a of the detection cylinder 5 also moves to the forward limit, and the dog 6 is moved to the limit. press switch S ₃ for detecting the over-stroke position.

Thus, the detection means 7 is provided at a position where the work on the fixed side is easy to perform. For this reason, even if a plurality of types of works W ₁ , W ₂ , W ₃ ... The number of the detection switches S ₂ , S ′ ₂ , S ″ _2, ... On the detection cylinder 5 side can be increased by the number of the corresponding works, and there is no need to change the setup according to the type of work.

In such a fluid circuit X, for example, if oil leakage occurs in a cylinder or a circuit, one of them does not completely return to the original position at the time of unclamping or at the start of use. In order to prevent this, the working cylinder 1 and the detecting cylinder 5
In response to the above, check valves 11 and 12 are provided as original position return compensation means in parallel with these.

That is, when the supply source Q supplies oil to the pressure chamber 10 of the detection cylinder 5 in order to operate the cylinders 1 and 5 in the unclamping direction from the clamped state, the piston 5a of the detection cylinder 5 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 reaches the home position earlier than the operation cylinder 1 for some reason, unless the check valve 12 is provided, the operation cylinder 1 stops on the way to the home position. Would. Therefore, although the working cylinder 1 is not retracted to the original position of unclamping position, thereby emitting a false signal that unclamped completed by detecting cylinder 5 and the switch S _1.

Therefore, in the fluid circuit X of FIG.
When the detection cylinder 5 reaches the original position, the oil is further supplied when the detection cylinder 5 reaches the home position, the hydraulic pressure in the left pressure chamber 10 and the hydraulic pressure in the flow path L1 exceeds the cracking pressure of the check valve 12, and the check valve 12 Is opened. Accordingly, oil is supplied from the supply source Q to the pressure chamber 3 via the flow path L1, the check valve 12, the flow path L2, and the throttle 18, and the piston 1a moves in the unclamping direction. The pressure chamber 2 is moved by the movement of the piston 1a.
Flows from the flow path L3 to the tank T via the electromagnetic switching valve 8.

Therefore, even though the detection cylinder 5 is first stopped at the right end, the oil passes through the check valve 12 and continues until the working cylinder 1 is completely returned to the original position (unclamped position). The pressure is continuously supplied to the first pressure chamber 3.

When the working cylinder 1 returns to the original position and stops, the hydraulic pressure in the pressure chamber 3 and the flow path L2 increases, and the check valve
When the cracking pressure exceeds 11 and an oil path is formed from the supply source Q to the flow path L1, the check valve 12, the flow path L2, the check valve 11, the throttle 13, the flow path L3, the electromagnetic switching valve 8, and the tank T, Keeps flowing by the amount set by the aperture 13.

Therefore, the two cylinders 1 and 5 always return to their original positions during unclamping, and continue to hold that position.

On the other hand, when the working cylinder 1 returns to the original position earlier than the detection cylinder 5 when the clamp is unclamped, if the check valve 11 is not provided, the detection cylinder 5 does not reach the original position. stopped halfway, can not be detected by the switch S ₁ the unclamping position of the working cylinder 1.

Therefore, by providing the check valve 11 in the fluid circuit X, when the working cylinder 1 returns to the original position and stops, if the supply of oil is further continued, one of the pressure chambers 3 of the working cylinder 1 is stopped. And the hydraulic pressure in the flow path L2 exceeds the cracking pressure of the check valve 11, and the check valve 11 is opened. Thereby, oil is supplied from the supply source Q to the flow path L1 and the pressure chamber 10, and the piston 5a is moved. At the same time, the oil in the pressure chamber 9 is discharged from the flow path L2 through the check valve 11, the throttle 13, the flow path L3,
It flows to the electromagnetic switching valve 8 and the tank T. Oil is continuously supplied to the pressure chamber 10 of the detection cylinder 5 until the detection cylinder 5 reaches the original position.

When the detection cylinder 5 reaches the original position and stops, the hydraulic pressure in the left pressure chamber 10 and the hydraulic pressure in the flow path L1 are increased by the check valve.
When the cracking pressure exceeds 12, the check valve 12 is opened. Thereby, the flow path L1, the check valve 12,
Flow path L2, check valve 11, throttle 13, flow path L3, electromagnetic switching valve 8
Then, an oil passage is formed to the tank T, and the oil continues to flow by a small amount in this passage. Therefore, also in this case, the cylinders 1 and 5 always return to the original positions, and continue to hold the positions.

Further, when the detection cylinder 5 is provided in the supply side flow path to the working cylinder 1 at the time of the unclamping operation, the second
In the clamped state shown in FIG.
Is clamping the work W, the working cylinder 1
Since the oil passage from the pressure chamber 3 to the detection cylinder 5 is always kept at a low pressure enough to overcome the frictional resistance of the cylinder and the like, and no high pressure is generated, the working cylinder 1 and the detection cylinder 5 Pipes and rotary joints 4
Leaks are very unlikely to occur in any part. Therefore, there is very little danger that the during-clamping detection cylinder 5 will move due to leaks, and the machining operation will not be unnecessarily interrupted.

On the other hand, if the piston 1a of the working cylinder 1 starts moving for some reason during clamping and the clamp is released, at the same time, the piston 5a of the detection cylinder 5 also moves to release the clamp detection, and an abnormality is detected. You.

In addition, by providing the check valves 11 and 12, the oil passage connecting the working cylinder 1 and the detection cylinder 5 does not completely block the working fluid therein, and upon completion of the unclamping operation, Since the oil passages passing through the check valves 11 and 12 are formed, the problem that the working fluid, for example, oil causes decay in the piping is eliminated.

[Modification] As another embodiment of the present invention, for example, a fluid circuit X 'as shown in FIG. 3 can be considered.

This is because in the circuit X of FIG. 1, the movement of the piston 5a of the detection cylinder 5 becomes heavy due to temperature change or other causes, and the piston 5a does not move unless the operating pressure is equal to or higher than the cracking pressure of the check valve 12. As a countermeasure against such a case, a sequence valve 14 is provided in the home position return compensation means on the detection cylinder 5 side instead of using the check valve 12. By adjusting the opening / closing operation pressure of the sequence valve 13, the normal operation of the detection cylinder 5 can be compensated.

Since the other parts are the same as those in the embodiment of FIGS. 1 and 2, the same parts are denoted by the same reference numerals and the description thereof will be omitted.

The check valve 11 on the side of the working cylinder 1 is connected as shown in FIGS. 1 to 3 and a third port at a position slightly before the retreating end of the working cylinder 1 as shown in FIG. 4, for example. By forming the step 15 and connecting the input side of the check valve 11 thereto, for example, during the unclamping operation, when the piston 1a is retracted, the check valve 11 is opened shortly before returning to the original position. .

For example, if the piston 1a is stopped halfway for some reason during the retreat, and the pressure in the pressure chamber 3 increases and the check valve 11 is opened at that time, the check valve 11 and the throttle 13 Is formed and the oil flows out to the tank, so that the pressure chamber 10 of the detection cylinder 5
Is supplied with oil. As a result, erroneous detection that the detection cylinder 5 detects unclamping is performed even though the working 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 retreating piston 1a exceeds the port 15, so that the piston 1a stops halfway. Even if an abnormal situation occurs, the detection valve 5 does not open at that time and the detection cylinder 5 also stops at the same time, so that erroneous detection is not performed.

Although only one working cylinder 1 is shown in FIGS. 3 and 4, a plurality of working cylinders 1 may be provided according to the clamping method as shown in FIGS. 1 and 2. .

[Effects of the Invention] According to the present invention, the operation of the working cylinder for the work clamp can be indirectly detected by, for example, a detection cylinder provided at a position that is easy to perform work separated from the working cylinder. Even in a device including a cylinder, only one detection cylinder is required, and the configuration of the entire clamp operation circuit is not complicated, and operability is improved.

Also, it is only necessary to provide detection means such as limit switches and dogs and electric wiring corresponding to the detection cylinder, and it is not necessary to provide detection means for each working cylinder at the movable side or at a remote position. It does not become complicated, the hydraulic piping and the electric wiring do not become complicated, and there is no problem in the mounting space and in the piping and the electric wiring.

Furthermore, even if the operating position of the working cylinder increases, it can correspond to the detecting cylinder and can be easily handled by increasing the number of limit switches and adjusting the position. Since detection is performed based on the flow rate of the working fluid, reliable operation detection can be expected.

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

In particular, since the home return compensation means is provided for each of the working cylinder and the detection cylinder,
Even if either of the two cylinders reaches the original position first, the respective original position return compensating means works at that time, and both cylinders are always returned to the original position, and the operation reference position and the detection reference position are surely As a result, erroneous detection or malfunction based on the detection is prevented.

In addition, by providing the detection cylinder in the flow path on the working fluid supply side during the unclamping operation, as long as the working cylinder maintains the clamped state during machining, the occurrence of a leak at the rotary joint portion is also reduced. Since the clamp detection state is maintained without moving the piston of the detection cylinder extremely, the trouble that the machining operation is unnecessarily interrupted is eliminated.

Furthermore, by operating the home return compensation means on the working cylinder side slightly before the piston of the working cylinder returns to the original position during the unclamping operation, for example, the working cylinder is stopped halfway and stopped. At that time, the origin return compensating means is not operated at that time and the detection cylinder is also stopped at the same time, so that erroneous detection is not performed and malfunction can be prevented.

In this manner, the detection cylinder always detects the movement of the working cylinder correctly, and performs accurate control.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of a clamp operation circuit of the present invention, showing an unclamped state, FIG. 2 is a circuit diagram showing a clamp 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 a check valve piping method, and FIG. 5 is a diagram showing a conventional clamp operating circuit. 1 ... working cylinder, 2 ... pressure chamber, 4 ... rotary joint, 5 ... detection cylinder, 9, 10 ... pressure chamber, 11, 12
... Check valve as in-situ return compensation means, 14... Sequence valve as in-situ return compensation means, Q... Fluid supply source, T... Tank, X, X ′.

Claims (1)

(57) [Claims] In a clamp operation circuit for performing a clamp operation and an unclamping operation of a work clamp working cylinder provided on a work mounting jig by a working fluid supplied from a working fluid supply source on a fixed portion side, Provided with a detection cylinder for detecting the movement of the working cylinder via a working fluid, the detection cylinder has two pressure chambers via a piston and has position detecting means for detecting the position of the piston, A first flow path connected to the working fluid supply source during the unclamping operation is connected to one pressure chamber of the detection cylinder, and the other pressure chamber of the detection cylinder and an unclamping pressure of the working cylinder. And a third flow path connected to the working fluid supply source during the clamping operation with the working fluid supply source. And when the pressure in the first flow path exceeds a predetermined pressure between the first flow path and the second flow path, the second flow path is connected to the second flow path. A first in-situ return compensation means for flowing a fluid into the flow path is provided, and a second flow path is provided between the second flow path and the third flow path when the pressure in the second flow path exceeds a predetermined pressure. A clamp operation circuit comprising a second original position return compensation means for flowing a fluid from a flow path to a third flow path.