JP2862965B2 - Fluid type clamp drive device and unclamping operation abnormality detection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid-type clamp driving device and an unclamping operation abnormality detecting device thereof.

(Prior art)

The applicant of the present invention has proposed a clamp operating circuit in a patent application of Japanese Patent Application No. 1-77525.

The clamp operating circuit connects an operating cylinder for clamping and a detecting cylinder for detecting the operation of the operating cylinder in series in a piping line of the pressure fluid, and also provides an original position return compensating means for the operating cylinder and the detecting cylinder. Connected in parallel, the movement position of the piston rod of the detection cylinder is detected by the position detection means, and the operation state of the working cylinder for clamping, that is, the operation state of the clamp / unclamp is indirectly detected by the detection cylinder and the position detection means. I do.

In the above-mentioned clamp operation circuit, when the piston rod of the operation cylinder or the detection cylinder quickly returns to the unclamping position during the unclamping operation, the original position return compensating means on the cylinder side that has returned quickly exceeds the cracking pressure and is opened. In order to continuously pass the pressure fluid, the piston rod of the other cylinder continues to move in the unclamping direction, and a reliable return to the original or unclamped position is compensated.

[Problems of the prior art]

Usually, the positioning or locating operation of the workpiece is performed before the unclamping operation. The working cylinder for this locating operation is controlled by another fluid drive system.
For this reason, electrical control means for sequential control is required between the locating working cylinder and the clamping working cylinder, and special consideration is required for synchronous control.

Also, during the unclamping operation, when the piston rod of the working cylinder or the detection cylinder comes into contact with an obstacle or the like and stops, the home position return compensating means is opened, so that the unclamping operation may not be completed. The unclamped state is detected by the detecting cylinder and its position detecting means. For this reason, even if the unclamped state is detected by the position detecting means, the working cylinder may not actually be set to the unclamped state, thereby causing a malfunction.

[Object of the invention]

Therefore, a first object of the present invention is to realize an order control of a working cylinder for locating and a working cylinder for clamping by a control element of a pressurized fluid, so that an electric control device can be omitted. .

A second object of the present invention is to prevent a malfunction by detecting an abnormal operation state in advance.

[Solution of the Invention]

In order to achieve the first object, the present invention provides a locating operation cylinder in parallel with a clamping operation cylinder, and locates the locating operation cylinder between these operation cylinders. Alternatively, an opening / closing control unit mechanically linked with the unlocating operation is interposed.

According to the present invention, in order to achieve the second object, a fluid-type clamp driving device is provided with a clamp abnormality detecting device.

[Function of the invention]

At the time of the clamping operation, the pressure fluid from the pressure fluid source first activates the locating working cylinder to bring the work into the positioning state. During the period from before the completion of the locating operation to after the completion of the locating operation, the locating operation cylinder is linked with the opening / closing control means, and by opening it, the clamping operation cylinder is driven in the clamping direction. . Therefore, in the clamping operation process, the clamping operation is automatically started at the time when the locating operation is completed or before or after the locating operation is completed.

Further, according to the embodiment in which the opening / closing control means is interlocked with the unlocating operation, during the unclamping operation, before and after the locating working cylinder completes the unlocating operation, the opening / closing control means is opened. The clamp working cylinder advances the unclamping operation before and after completing the unlocating operation.

As described above, the locating operation or the unlocating operation always operates prior to the clamp operation or the unclamping operation without using the electric control means.

On the other hand, the home position return compensating means does not enter the open state during the clamping operation, but during the unclamping operation, one of the working cylinder or the detecting cylinder hits an obstacle or the like and stops halfway, or the other one. When returning to the original position, that is, the unclamping position,
The opening state is established, and the returning of the unreturned working cylinder or detection cylinder to the original position is compensated.

In the unclamping operation, the time comparing means compares the unclamping operation time from the start of unclamping to the end of unclamping with the reference unclamping operation time, and the unclamping operation time is longer than the reference unclamping operation time. When the pressure response time is long, or when the pressure response time from the start of unclamping to the pressure switch response is compared with the reference pressure response time and the pressure response time is shorter than the reference pressure response time, an abnormal signal is output.

As described above, the time comparing unit detects an abnormality in the unclamping operation by detecting a time change during the unclamping operation, and generates an abnormal signal. Therefore, when an abnormal signal is generated, the operator checks the unclamping state, performs necessary operations, and then proceeds to the next step to prepare for an unexpected accident.

Embodiment 1 (FIGS. 1, 2, and 3) FIG. 1 shows the configuration of a fluid-type clamp driving device 1 and an unclamping operation abnormality detecting device 30.

The fluid-type clamp driving device 1 includes one or more clamping operation cylinders 2, one operation detection detection cylinder 3, original position return compensation means 4, 5, position detection means 6,
It is assembled by a working cylinder 34 for locating, opening / closing control means 35 and the like.

A pressure fluid 7 such as a driving pressure oil for these is supplied from a pressure fluid source 8 by a pipe 9. That is,
The pressure fluid source 8 is connected by a pipe 9 via a check valve 10 and a relief valve 11 to an input port of a direction switching valve 12 at an electromagnetically operated 4-port 3-position. The two switching ports of the direction switching valve 12 are connected to the cylinder chambers 2a and 2b of the working cylinder 2 and the cylinder chambers 34a and 34b of the working cylinder 34 via the pipe 9 and the rotary joint 17 of the reciprocating path and, if necessary, the throttle valve 38. Are connected in parallel with each other, and are connected in series with the cylinder chambers 3a and 3b of the detection cylinder 3.

The electromagnetic operation devices 28 and 29 of the direction switching valve 12 are switched by a clamp operation switch 24 and a driver 26 and an unclamping operation switch 25 and a driver 27, respectively, and the switching state is maintained by a mechanical positioning mechanism. The return port of the direction switching valve 12 is connected to the tank 18.

The working cylinder 34 for locating is connected in parallel to the working cylinder 2 on the upstream side of the working cylinder 2 with the throttle valve 38 interposed therebetween. Further, the opening / closing control means 35 is provided between the working cylinder 2 and the working cylinder 34,
It is incorporated in a portion of the pipe 9 corresponding to the supply of the pressure fluid 7 at the time of clamping, and is constituted by a pilot valve 36 having a check function with respect to the supply direction at the time of clamping. The pilot pin 36a of the pilot valve 36 is incorporated so as to be mechanically linked at a position corresponding to a period from before the locating operation of the piston rod 34c of the working cylinder 34 is completed to after it is completely completed.

The in-situ return compensation means 4 and 5 of this embodiment are respectively constituted by a series-connected check valve 13 and throttle valve 15, and a series-connected check valve 14 and throttle valve 16, and these check valves 13 and 14 are Pressure fluid during clamp operation 7
Is connected in the direction in which the non-return function works with respect to the supply direction, and is opened by the cracking pressure in the supply direction at the time of unclamping opposite to this direction.

In order to detect the movement of the piston rod 3c of the detection cylinder 3, the position detection means 6 determines the position of the dog 19 attached to the piston rod 3c by using a limit switch 20 for detecting unclamping, and a limit switch for detecting clamp.
21 and 22, and a limit switch 23 for detecting overstroke. Here, the clamp detection limit switches 21 and 22 are used corresponding to works of different sizes.

The unclamping operation abnormality detecting device 30 of the first embodiment includes an unclamping detecting limit switch 20, an unclamping operation switch 25, and a setting device 32 on the input side.
Time comparison means 31 connected to the
It has an alarm 33 connected to 31.

When the directional control valve 12 is switched to the parallel flow path state shown in FIG. 1 and the pressurized fluid 7 is supplied to the cylinder chamber 3b of the detection cylinder 3 and the cylinder chamber 2b of the plurality of working cylinders 2, the pistons thereof The rods 2c and 3c are retracted to the unclamping positions as original positions. Similarly,
The piston rod 34c of the working cylinder 34 also retreats and is at the unlocated position. This state can be confirmed by, for example, an “H” level output signal from the limit switch 20 for unclamping detection.

In this state, when the operator or the controller turns on the clamp operation switch 24, drives the electromagnetic actuator 28 via the driver 26, and switches the flow path of the direction switching valve 12 in the cross direction, the pressure from the pressure fluid source 8 Pressure fluid 7
First, the cylinder chamber 34a of the operating cylinder 34 for locating
, The piston rod 34c is advanced, and as shown in FIG. 2, the locating pin 41 at the tip of the piston rod 34c is pressed against the locating hole 43 of the work 42 to bring it into a positioning state.

During a period from before the completion of the locating operation to after the completion, the piston rod 34c is moved to the most advanced position to open / close the opening / closing control means 3.
In order to open the pilot valve 36 by driving the pilot pin 36a of the pilot valve 36 inside 5, the pressure fluid 7
Enters the inside of the cylinder chamber 2a of the working cylinder 2 through the opening / closing control means 35, and advances the piston rod 2c in the clamping direction. Accordingly, the piston rod 3c advances from a predetermined direction, and thereby hits the workpiece 42 with the clamp piece 40 at the distal end, and is brought into a clamped state with a predetermined clamp force.

During this clamping operation, the pressure fluid 7 inside the cylinder chamber 2b is pushed out by the piston rod 2c, enters the inside of the cylinder chamber 3a of the downstream detection cylinder 3, moves the piston rod 3c forward, and clamps with the dog 19. Work 42
For example, the limit switch 21 corresponding to is turned on. Thereby, the clamp completion state can be confirmed. Here, when all the working cylinders 2 are in the clamped state, the total flow rate of the pressure fluid 7 discharged from the cylinder chamber 2b is determined by the limit switch 21 corresponding to the workpiece whose piston rod 3c of the detection cylinder 3 is being clamped. It is the flow rate necessary to move forward.

During this clamping operation, the working cylinder 2 is always located on the upstream side of the detection cylinder 3 with respect to the supply direction of the pressurized fluid 7, so that the detection cylinder 3 is Prior to this, the clamp is not completed. Also, the original position return compensation means 4,
The check valves 13 and 14 inside 5 always function as a check,
It does not open to any pressure of the pressure fluid 7.

Thus, the operating cylinder 34 for locating is located on the upstream side of the operating cylinder 2 for clamping, and the opening / closing control means 35 interlocked with the operating cylinder 34 is interposed between the operating cylinder 34 and the operating cylinder 2. Therefore, even if there is no electrical sequence control device, in the course of the clamping operation, the locating operation cylinder 34 operates first, and after the locating operation is completed, the operation cylinder 2 operates and the clamping operation is performed. Is performed.

Next, when the operator or the controller turns on the unclamping operation switch 25 for the unclamping operation, the direction switching valve 12 forms a parallel flow path, so that the pressure fluid 7 from the pressure fluid source 8 is First, the piston rod 3c enters the cylinder chamber 3b of the upstream detection cylinder 3 and retreats. At this time, the pressure fluid 7 inside the cylinder chamber 3a enters the inside of the cylinder chambers 34b, 2b of the downstream working cylinders 34, 2 and the piston rods 34c, 3c
Are set to the unlocated state and the unclamped state almost at the same time.

In the process of ending the unclamping, the dog 19 of the piston rod 3c hits the limit switch 20 for detecting the unclamping, so that the position detecting means 6 confirms the unclamping state.

During the unclamping operation, when the piston rod 3c hits an obstacle or the like and stops without completely retreating to the unclamping position, or returns to the original position earlier than the working cylinder 2, the cylinder chamber 3b of the detecting cylinder 3 Internal pressure builds up. When the internal pressure exceeds the cracking pressure of the check valve 14, the check valve 14 is opened, so that the pressure fluid 7 for the unclamping operation is
The air is supplied to the cylinder chambers 2b and 34b of the working cylinders 2 and 34 over time while passing through the check valve 14 in the open state and the flow rate is restricted by the throttle valve 16. Therefore, when an abnormal operation occurs on the side of the detection cylinder 3, the home position return compensating means 5 continues to operate the cylinder chambers of the working cylinders 2 and 34.
By supplying the pressurized fluid 7 to 2b and 34b, the piston rods 2c and 34c of the working cylinders 2 and 34 completely return to their original positions while spending more time than normal.

Conversely, when all the working cylinders 2, 34 return to the unclamping position or the unlocating position earlier than the detection cylinder 3, if the pressure fluid 7 is continuously supplied to the cylinder chambers 3b, 34b, the cylinder chamber 3a And cylinder chamber 2b,
At the point when the internal pressure of the pipe 9 between the pipe 34 and the pipe 34b exceeds the cracking pressure of the check valve 13, the home position return compensating means 4
The check valve 13 is opened, and the throttle valve 15 flows into the tank 18 while restricting the flow rate. During this time, the detection cylinder 3 completely returns to the unclamping position.

As described above, in the course of the unclamping operation, in addition to the above-described abnormal operation, the working cylinders 2 and 34 and the detection cylinder 3 are not synchronized with each other due to a volume change due to a temperature change of the pressure fluid 7 and the unclamping operation. When the return time to the position does not match, the original position return compensating means 4 and 5 operate the check valve 1.
Open the cylinders 3 and 14 and restrict the flow rate while
4 and the complete return of the detection cylinder 3 to its original position is compensated.

On the other hand, the time comparing means 31 inside the unclamping operation abnormality detecting device 30 is constituted by, for example, a resettable timer, and measures the time from the start of the unclamping operation by the unclamping start signal from the unclamping operation switch 25. The operation is started, and the timekeeping operation is stopped and reset by the output signal from the unclamping detection limit switch 20.

During normal operation, that is, as shown in FIG. 3, the unclamping operation time Ta from the start of the unclamping operation to the completion of the unclamping operation is shorter than the reference unclamping operation time Tas set in advance by the setting unit 32. At this time, since the time comparing means 31 is reset by the output signal of the limit switch 20 before the time-up state, the abnormal signal is not generated. However, the unclamping operation time Ta
Is longer than the reference unclamping operation time Tas,
The time comparing means 31 enters a time-up state, generates an abnormal signal, stops the processing operation and the like, and operates the alarm 33. This allows the operator to
Checking the warning light or sound from 33, knowing that the operation is abnormal, and taking necessary measures and measures for the processing equipment.

Embodiment 2 (FIG. 4) Embodiment 2 is an example in which the opening / closing control means 35 is constituted by two pilot valves 36 and 37 and a throttle valve 39 as required.

The pilot valve 37 is in a direction in which the check function does not work with respect to the supply direction of the pressure fluid 7 at the time of clamping.
The pilot pin 37a is linked in series with a position near the completion of the unlocating operation of the locating working cylinder 34. The throttle valve 39 is connected in parallel with the pilot valve 37.

During the clamping operation, the pilot valve 36 is opened after the locating operation by the working cylinder 34 is completed, as described above. At this time, the pilot valve 37 opens with the pressure in the supply direction of the pressure fluid 7 at the time of clamping to allow supply in the clamping direction. Therefore, during this clamping, the throttle valve 39 does not substantially operate.

Further, at the time of unclamping, since the pressure fluid 7 is supplied in the direction at the time of unclamping, the working cylinder 34 retreats ahead of the clamping working cylinder 2 and takes an appropriate time limited by the throttle valve 38. While completing the unlocating operation. During this unlocating operation, the pilot valve 37 inside the opening / closing control means 35 moves the pressure fluid 7 inside the cylinder chamber 2a.
, The pressure fluid 7 inside the cylinder chamber 2a flows out little by little at the flow rate restricted by the throttle valve 39. As a result, the clamping force by the working cylinder 2 is reduced. In this state, the working cylinder 34 proceeds with the unlocating operation.

When the unlocating operation is nearly completed or completely completed, the piston rod 34c pushes the pilot pin 37a of the pilot valve 37 to open and close the pilot valve 37. At this time, the pressure fluid 7 inside the cylinder chamber 2a of the working cylinder 2 passes through the pilot valves 36 and 37 of the opening / closing control means 35 without any flow rate restriction.

The throttle valve 39 inside the opening / closing control means 35 can be omitted because it is not an essential element. When the throttle valve 39 is omitted, the pilot valve 37 is opened when the unlocating operation is completely completed.
Starts the unclamping operation after the end of the unlocating operation.

Also in this embodiment, the unclamping operation abnormality detection device 30
Works in the same manner as in the first embodiment.

[Other Embodiments (FIG. 5)] In each of the above embodiments, the original position return compensating means 4 and 5 are constituted by the check valves 13 and 14 and the throttle valves 15 and 16. 4 and 5 can be configured by combining throttle valves 15 and 16 and sequence valves 44 and 45 as shown in FIG. However, in any of the embodiments, the throttle valves 15 and 16 are necessary when detecting an abnormality in the unclamping operation, and are unnecessary when the abnormality is not detected.

Further, in the above embodiment, the time comparing means 31 is constituted by a timer, but this function can also be realized in the field of a program by using a control / calculation / comparison function of a CPU or the like.

〔The invention's effect〕

 In the present invention, the following specific effects can be obtained.

First, an opening / closing control means interlocking with the locating operation cylinder is interposed between the locating operation cylinder and the clamping operation cylinder, and after the locating operation or the unlocating operation, the clamping operation or the unclamping operation is performed. Is performed, electric sequential control means is not required, and necessary sequential operations can be reliably performed only by fluid control.

Secondly, if the unclamping operation time is longer than the reference unclamping operation time during abnormal unclamping operation, this state is detected by the time comparing means, and an abnormal signal is generated. This can be prevented beforehand, and appropriate measures can be taken.

[Brief description of the drawings]

FIG. 1 is a piping diagram of a fluid-type clamp driving device and a block diagram of an unclamping operation abnormality detecting device according to a first embodiment, FIG. 2 is a sectional view of a clamped state of a work, and FIG. FIG. 4 is a piping diagram of a hydraulic clamp driving device according to a second embodiment and a block diagram of an unclamping operation abnormality detecting device. FIG. 5 is a piping diagram of another embodiment of the in-situ return compensation means. DESCRIPTION OF SYMBOLS 1 ... Fluid type clamp driving device, 2 ... Clamping operation cylinder, 3 ... Detection cylinder, 4 ... Original position return compensation means, 6 ... Position detection means, 7 ... Pressure fluid, 8
…… Pressure fluid source, 9… Piping, 12… Electromagnetically operated directional switching valve, 13, 14 …… Check valve, 15, 16 …… Throttle valve, 24 …… Clamp operation switch, 25 …… Unclamp Operation switch, 30 ... Unclamp operation abnormality detection device,
31: Time comparison means, 32: Setting device, 33: Alarm device, 34
…… Operating cylinder for locating, 35 …… Open / close control
36, 37 ... Pilot valve, 39 ... Throttle valve.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B23Q 3/06 B23Q 17/00

Claims (5)

(57) [Claims] 1. A working cylinder for locating is connected in parallel with a working cylinder for clamping on the upstream side of a pressure fluid, and the working cylinder of the working cylinder is provided in a pipe line between the working cylinder and a pressure fluid source. A detection cylinder for operation detection is connected in series, and opening and closing control means interlocked with the locating operation cylinder is interposed between the clamping operation cylinder and the locating operation cylinder,
A common home position return compensating means is connected in parallel to the two working cylinders, and a home position return compensating means is connected in parallel to the detecting cylinder, and the position corresponding to the moving position of the piston rod of the detecting cylinder is further adjusted. A fluid-type clamp driving device comprising a detection unit. 2. The hydraulic clamp driving device according to claim 1, wherein said opening / closing control means is constituted by a pilot valve interlocked with a locating operation of said locating working cylinder. 3. The fluid according to claim 1, wherein said opening / closing control means comprises a pilot valve interlocked with a locating operation of said locating working cylinder and a pilot valve interlocked with an unlocating operation. Type clamp drive. 4. A throttle valve which is connected in parallel to said opening / closing control means for a pilot valve linked to a locating operation of said operating cylinder for locating, a pilot valve linked to an unlocating operation, and a pilot valve linked to an unlocating operation. 2. The fluid-type clamp driving device according to claim 1, wherein the fluid-type clamp driving device is constituted by: 5. A working cylinder for locating is connected in parallel to the working cylinder for clamping on the upstream side of the pressure fluid, and the working cylinder is located in a pipe line between the working cylinder and a pressure fluid source. A detection cylinder for operation detection is connected in series, and opening and closing control means interlocked with the locating operation cylinder is interposed between the clamping operation cylinder and the locating operation cylinder,
A home position return compensating means with a throttle function common to both working cylinders and an original position return compensating means with a throttle function to the detection cylinder are connected in parallel, respectively. In the fluid type clamp driving device, a position detecting means is provided corresponding to the movement position of the unclamping operation time from the start of the unclamping to the completion of the unclamping detected by the position detecting means. An unclamping operation abnormality detecting device, comprising: a time comparing unit that compares an unclamping operation time and outputs an abnormality signal when the unclamping operation time is longer than a reference unclamping operation time.