JPS62181846A - Work clamp device - Google Patents

Abstract

PURPOSE:To make it possible to control actuating cylinders from only one position, by providing a working fluid flow rate detecting means for detecting the flow rate of working fluid for each actuating cylinder, in a fluid circuit connecting between the actuating cylinders and fluid supply source. CONSTITUTION:A plurality of actuating cylinders 6 are laid around a workpiece loading bed, the base end of a clamp pawl for clamping a workpiece W is coupled to the front end of a rod 7 in each actuating cylinder 6. A fluid circuit X is connected to the extension side pressure chamber 11a and the retraction side pressure chamber 11b which are defined by a piston 6a within each cylinder 6. This fluid circuit X is provided therein with a working fluid detecting means 20 for detecting the flow rate of working fluid for each cylinder 6 and controlling each cylinder. This working fluid flow rate detecting means 20 is composed of a flow metering cylinder 22 provided with a return cylinder 21, a detector 23 for detecting the stroke amount of the flow rate cylinder 22, a leakage compensating means 24 of the cylinders 6 and a solenoid valve 25.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a workpiece clamping device implemented, for example, in one station of a transfer machine, and more specifically, workpiece mounting is an operation for clamping workpieces of different sizes to a jig. This invention relates to an improvement of a work clamp device that controls a cylinder.

BACKGROUND TECHNOLOGY Conventionally, in a workpiece clamping device implemented at one station of a transfer machine, for example, when clamping workpieces of different heights, it is necessary to change the pivot point of the workpiece clamp arm depending on the height of the workpieces. Ta.

At the same time, it is also necessary to change the connection points of each actuating cylinder connected to the work clamp arm. In this case, the limit switch and dog that control the forward position, clamp position, overstroke position, etc. of each actuating cylinder must be changed. It was necessary to change the setup, such as changing the installation position of the detector and increasing the number of detectors.

That is, in the case of a conventional detector installed in an operating cylinder, at least two limit switches and dogs are required, and each additional limit switch and dog must be added for each additional operation. However, there were various problems with installation, such as space issues, increased costs, and maintenance.

In addition, in the case of a workpiece clamping device equipped with a fixture for fixing and tilting or rotating a workpiece in a transfer machine, etc., if limit switches and dogs are attached to the device itself depending on the number of operating cylinders, There is a problem with the processing of electrical wiring, etc. Furthermore, when the limit switch and the dog are provided on the bed on the fixed side, their positions are fixed.

Furthermore, in the case of the method of detecting the clamp state based on the operating pressure of the operating cylinder, there is a problem in that the position of the cylinder cannot be confirmed.

In this way, in the case of conventional workpiece clamping equipment, for example, when attempting to process workpieces by clamping several types of workpieces with different heights with one workpiece clamping equipment, it is necessary to It is said that the setup work, such as changing the pivot point of the work clamp arm or changing the control device of multiple actuating cylinders, is extremely troublesome, and requires a lot of time and effort, resulting in extremely low work efficiency. There was a problem.

Purpose of the Invention The present invention has been devised in view of the above-mentioned conventional technical problems, and its purpose is to enable the control of the actuating cylinder to be changed by a simple operation. Even when clamping workpieces of different sizes,
To provide a workpiece clamping device capable of easily and surely changing setups without requiring much effort and time, and efficiently performing workpiece clamping work.

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a work clamping device in which a work cylinder for driving a clamp claw for clamping the work is installed on a jig for mounting the work.
The gist of the present invention is that an operating flow rate detection means for detecting the operating flow rate of the operating cylinder is provided in a fluid circuit connecting the operating cylinder and the fluid supply source.

Examples of the invention The present invention will be described in detail below based on the accompanying drawings.

Figures 1 and 2 show a front view and a plan view of a work clamp device at one station of a transfer machine embodying the present invention. Workpiece mounting table 3 on base 2
A support plate 4 for lifting and lowering the workpiece W is provided at the center of the workpiece mounting table 3 via a lifting mechanism 5.

A plurality of actuating cylinders 6 are arranged around the workpiece mounting table 3.
are installed (in this example, six are installed),
A proximal end of a clamp claw 8 for clamping the workpiece W is connected to the tip of the rod 7 of the operating cylinder 6.

The central part of the clamp claw 8 is swingably supported on the workpiece mounting table 3 via a bin 9, and a locate pin 10 for positioning the workpiece W is retracted from the workpiece mounting table 3 via a lifting mechanism (not shown). It is set freely.

An extension side pressure chamber 11 defined by the piston 6a of each working cylinder 6. a and the contraction side pressure chamber 11b,
As shown in FIG. 3, a fluid circuit X is connected to a supply source Q of working fluid (hydraulic pressure). The fluid circuit X is provided with an operating flow rate detection means 20 that detects the operating flow rate of each operating cylinder 6 and controls the operation of each cylinder.

This operating flow rate detection means 20 includes a flow metering cylinder 22 equipped with a return cylinder 21, and a flow rate metering cylinder 22 provided with a return cylinder 21.
2, a leak Ni1 means 24 to the cylinder 6 that opens at the end of the stroke of the flow metering cylinder 22, and an electromagnetic switching valve 25. As shown in FIG. 4, a stopper 27 is provided at the left end of the return cylinder 21 as an adjustment member for regulating the backward limit position of the piston 21b, and its protrusion amount can be adjusted. In addition, the flow metering cylinder 22
At the right end of the valve 28, an opening/closing rod 28a of a valve 28 constituting the leak compensating means 24 is always urged by a spring 28b and protrudes, so that the valve 28 is closed.

This leak compensation means 24 operates when there is oil leak in the fluid circuit X or the working cylinder 6. In other words, if there is a leak for some reason, the pressure inside the pressure chamber A will drop and the piston rod 22a of the flow metering cylinder 22 will drop.
is pushed by the oil pressure in the pressure chamber B from the supply source Q, and the cylinder 2
2 reaches the stroke end, that is, the right end. At that time or during the process, the piston 22b moves to the opening/closing rod 2.
8a against the spring 28b, the valve 28 is opened as shown in FIG. As a result, pressure oil from the supply source Q passes through the leak compensating means 24 to the boat 29, the pressure chamber A,
It passes through the boat 30 and is directly supplied to the pressure chamber 11a of the working cylinder 6 to maintain the clamping pressure of the cylinder 6.

The flow rate cylinder 22 has a capacity adjusted by a stopper 27 to match the amount required for the operation of each actuation cylinder 6, and the tip of the piston rod 22a of the flow metering cylinder 22 is provided with a clamp at the retracted position of the actuation cylinder d. position,
Limit switch L whose position is adjusted to correspond to each overstroke position etc. and detects each position.
A dog 26 is provided which comes into contact with a detector 23 consisting of S, LS2, LS3, etc.

In such a configuration, when the work is clamped, pressure oil from the supply source Q enters the pressure chamber of the cylinder 22 through the boat 31 and pushes the piston 22b to the right. At this time, pressure chamber A
The pressure oil inside is transferred from the boat 3o to the cylinder 6 via the fluid circuit
into the pressure chamber 11a. The piston rod 22a moves to the right as the pressure oil in the pressure chamber B increases,
At the same time, the piston rod 7 also moves to the left and its working end comes into contact with the workpiece W as shown by the imaginary line in FIG. 3, and the rightward movement of the piston rod 22a is stopped at the position of the imaginary line. At this time, the dog 26 of the piston rod 22a
comes into contact with limit switch LS2, and work clamping is detected.

On the other hand, in order to move the operating cylinder 6 backward, the electromagnetic switching valve 25
is switched to allow pressure oil from the supply source Q to flow into the pressure chamber 11b via the return cylinder 21.

At this time, the pressure oil flowing into the pressure chamber 11b pushes the piston 6a in any direction, pushing out the pressure oil in the pressure chamber 1.1a. This pressure oil enters the pressure chamber A from the boat 30. During this time, the piston 21b is moved to the left by the pressure oil in the return cylinder 21, and accordingly, the piston rod 22a is also moved to the left. The hydraulic pressure in the pressure B flows out to the tank T through the boat 31 and the electromagnetic switching valve 25. At the same time, the hydraulic pressure in this pressure chamber B is reduced by the pilot check valve 32 (return cylinder 2
Opened by hydraulic pressure from 1. ) and boat 30 to pressure chamber A.

Furthermore, the movement of the piston rod 22a to the left releases the pressure on the opening/closing rod 28a by the piston 22b, and the returning force of the spring 28b causes the opening/closing rod 28a to return to the left, thereby closing the valve 28.

When the actuating cylinder 6 reaches the retracted position, the leftward movement of the piston rod 22a is stopped by the stopper 27, and the dog 26 comes into contact with the limit switch LS, as shown by the solid line in FIG. 3, and the retracted position is detected. Ru.

As described above, in the above embodiment, the flow metering cylinder 22 corresponding to the total capacity of each working cylinder 6 is provided, and the working fluid discharged from the total flow metering cylinder 22 is detected by the stroke amount of the piston rod 22a. By this, the retracted position and clamp position of the plurality of actuating cylinders 6,
Positioning such as the overstroke position is controlled by one operating flow rate detection means 20.

*, Figure 5 shows the second embodiment of the present invention, so this embodiment corresponds to three different types of workpieces W, and the operating cylinder 6 is connected to limit switches +-S2, LS3, and LS4.
This is carried out when detecting three positions during clamping.

In this embodiment, leakage compensation for the cylinder 6 is performed by a solenoid valve 84. Limit switch LS2, LS3, LS with dog 26 compatible with three types of workpieces
4, the solenoid valve 34 switches from the 8 state shown in FIG.
is supplied to maintain the clamping pressure of the cylinder 6.

Note that the other configurations are the same as those of the first embodiment, so the same reference numerals are given and the explanation will be omitted.

In this configuration, pressure oil from the supply source Q flows into the pressure chamber B of the cylinder 22 from the port 36 during work clamping. As a result, the piston 22b is pushed to the right and the pressure chamber A
The pressure oil flows into the pressure chamber 11a of the cylinder 6 from the port 37. The piston 22b stops moving to the right when the piston rod 7 comes into contact with the work W in three different strokes, that is, at the clamp positions P2, P3, and P4. At this time, the dog 26 comes into contact with one of the limit switches LS2, LS3, and LS4 corresponding to the three types of clamp positions P1, P2, and P3 of the piston rod 7, and workpiece clamping is detected.

In this way, when the dog 26 comes into contact with the limit switch that corresponds to the type of work W to be clamped, the solenoid valve 34 opens, and pressure oil passes through the pressure chamber A of the cylinder 22 and is supplied to the pressure chamber 11a of the cylinder 6. and compensate for subsequent leaks.

On the other hand, in order to move the cylinder 6 backward, the electromagnetic switching valve 25 is switched. Pressure oil from the supply source Q passes through the cylinder 21 and flows into the pressure chamber 11b, pushing the piston 6a to the right.

At this time, the solenoid valve 34 is demagnetized, and the hydraulic pressure from the supply source Q is not supplied to the pressure chamber A from the port 35. Pressure chamber 1
Pressure oil in 1a is pushed by piston 6a, passes through port 37, and flows into pressure chamber A in cylinder 22. The hydraulic pressure from the pressure chamber B then flows out to the tank T through the port 36.

The piston rod 22a moves to the left by the pressure oil in the pressure chamber A and the cylinder 21, and the dog 26 comes into contact with the limit switch LS for detecting the backward position.

Next, FIG. 6 shows an eighth embodiment of the present invention, in which a small flow metering cylinder 22 is used as a meter to count a fixed amount of operating flow rate, and a plurality of operating cylinders 6 are connected to each other. This method outputs a signal for each unit flow rate and counts this signal to detect the operating flow rate.

In this case, the operating flow rate detection means 20 is a detector 2 that comes into contact with the flow metering cylinder 22 and the dog 26 of the cylinder rod 22a to detect a constant stroke of the cylinder rod 22a.
3, a counter 38 that counts signals from the limit switch LS, a switching valve 39 that is mechanically switched by a constant stroke of the cylinder rod 22a, and the like.

The switching valve 39 has a structure as shown in FIG. 8, for example. A switching lever 61 whose distal end engages with a notch 60 of the piston rod 22a is attached to the tip of the opening/closing rod 59 of the switching valve 39, and is held in two positions by a spring 62. FIG. 8 [+] shows the state of the piston 22b position in FIG. 6, where hydraulic pressure enters pressure chamber B and flows out from pressure chamber A. When the piston 22b moves to the right by a predetermined stroke, the switching lever 61 is pushed at the left end of the notch 60 and is elastically moved by the spring 62 as shown in FIG.
+1], and the opening/closing rod 59 moves to the left. That is, as shown in FIG. 7, the switching valve 39 switches so that the hydraulic pressure enters the pressure chamber A and flows out from the pressure chamber B.

The above operations are repeated.

Note that the other configurations are the same as those in the first embodiment, are given the same reference numerals, and explanations are omitted.

In this configuration, pressure oil from the supply source Q during work clamping passes through the switching valve 39 and enters the pressure chamber B of the cylinder 22 from the boat 40, as shown in FIG.

As a result, the piston 22b is pushed to the right to cause the pressure oil in the pressure chamber A to flow out from the boat 41. Pressure oil flowing out from the boat 41 passes through the switching valve 39 and enters the pressure chamber 1 of the cylinder 6.
1a. As shown in Fig. 7, the piston rod 22a
moves to the right, and when the dog 26 comes into contact with the limit switch LS, the switching valve 39 switches. Pressure oil from the supply source Q flows into the pressure chamber A of the cylinder 22 from the boat 41.

As a result, the piston 22b is pushed to the left, causing the pressure oil in the pressure chamber B to flow out from the boat 40. Pressure oil passes through the switching valve 39 and flows into the pressure chamber 11a of the cylinder 6. When the piston 22b is in the position shown in FIG. 6, the switching valve 39 again reverses the flow to the switching cylinder 22. Such an operation is repeated, and each time the dog 26 comes into contact with the detector 23 (LS), the detector 23 (LS) outputs a signal, and the signal is counted by the counter 38. The flow rate sent to the pressure chamber 11a between adjacent signals becomes a constant value equal to twice the volume of the shaded area in the cylinder 22 in FIG. By multiplying this constant amount by a count number, the total flow rate of pressure oil to the cylinder 6 is determined. This total flow rate is preset to the amount necessary to push the piston rod 7 leftward and move the work W to the clamping position, and the above-mentioned count number is set for this, and the counter 38 counts this set count number. This allows workpiece clamping to be detected.

At this time, the piston 22b is stopped by the piston rod 7 of the working cylinder 6 coming into contact with the workpiece W. For example, if a leak occurs in the fluid circuit X or the working cylinder 6 for some reason, the pressure in the pressure chamber A or B of the cylinder 22 will drop rapidly. At this time, the piston 22b supplies hydraulic pressure from the supply source Q to the pressure chamber 11a of the cylinder 6 via the switching valve 39 to maintain the clamp pressure.

On the other hand, when retracting the piston rod 7 of the cylinder 6, the electromagnetic switching valve 25 is switched. Pressure oil from the supply source Q flows into the pressure chamber 11b of the cylinder 6. The piston 6a is pushed to the right, and the pressure oil in the pressure chamber 11a passes through the check valve 43 and flows out into the tank T.

The flow metering cylinder 22 of this embodiment is small, so it has the feature that it can be used for general purposes.

Next, FIG. 9 shows a fourth embodiment of the present invention.
0 was used, whereas the operating flow rate detection means 20 of this embodiment is provided with a hydraulic motor 44 instead of the flow rate measuring cylinder 22, and a hydraulic motor as a fluid pressure motor connected to the oil of the fluid circuit X. Detector 23 detects a certain amount of rotation of 44.
Counter 4 which is a pulse signal detected by and proportional to the amount of rotation
5, the positions of the plurality of actuating cylinders 6, such as the retreat position, clamp position, overstroke position, etc., are detected based on the counted number.

In this case, the above-mentioned count number can be set by the setter 46, 47, 48 of the external controller 59 as shown in FIG. can. Then, the number counted by the counter 45 is displayed on the display 50 provided in the upper part.

Further, 49 is a setter for the reel clamp, that is, for the retreat position. 51, 52, 53, and 54 are terminals for unclamping and detection selection of each clamp, which light the lamp of the corresponding setting device. 55 is a power supply terminal. This external controller 59 can also be applied to the third embodiment.

As the operating flow rate detection means 20 of this embodiment, for example, the first
A flow meter as shown in FIG. 1 is used, and its terminal 56 is connected to the external controller 59 described above. Boat 44 with hydraulic motor 44
The turbine blade 57 is rotated in accordance with the flow rate of the hydraulic pressure supplied from the boat 44b, and the amount of rotation is transferred by a pickup 58 as a detection means, and a pulse signal proportional to the amount of rotation is sent to the controller 59. It looks like this.

The clamp position of the rod 7 of the cylinder 6 is detected when the numerical value displayed on the display 50 matches the setting value of the corresponding setting device 46, 47, 48, 49.

It should be noted that the detection accuracy improves as the detection rotational speed is reduced, and the detection accuracy can be easily applied to the operating ends of a plurality of operating cylinders 6.

Note that the other configurations and operations are the same as those in the first embodiment, so the same reference numerals are given and explanations thereof will be omitted.

Effects of the Invention The present invention provides a workpiece clamping device in which a working cylinder for driving a clamp claw for clamping a workpiece is installed on a jig for mounting a workpiece as described above. Since the circuit is provided with an operating flow rate detection means for detecting the operating flow rate of the operating cylinder, the following excellent effects can be achieved.

(a) Since one working cylinder can be controlled by a working flow rate means installed at one location that is easy to adjust, only one flow rate detection means is required even in devices consisting of multiple working cylinders, making the overall structure of the work clamp device complicated. This improves operability.

(b) Since there is no need to provide a limit switch, a detector such as a dog, or electrical wiring to each operating cylinder, the device does not become complicated and chip disposal is advantageous.

Particularly in the case of a conventional work clamping device that tilts or rotates a workpiece in a transfer machine or the like, limit switches and dogs are attached to the device itself depending on the number of operating cylinders, and this can be effectively implemented in such cases.

(C) 9 Even if the number of operating positions of the operating cylinders increases, there is no need to increase the number of detectors, and since the flow rate of the working fluid of the operating cylinders is detected and controlled, reliable operation detection can be expected.

(d) Also, since the structure is simple, it can be manufactured at low cost and maintenance is easy.

(e) When the workpiece is clamped, hydraulic pressure is always applied to the actuating cylinder to maintain the clamping force, so even if a leak occurs for some reason, the clamping can be reliably maintained.

[Brief explanation of drawings]

Fig. 1 is a front view of a work clamp device embodying the present invention, Fig. 2 is a plan view of pit 1, Fig. 3 is an explanatory diagram of a fluid circuit equipped with an operating flow rate detection means for controlling an operating cylinder,
FIG. 4 is a cross-sectional view of the main part of the operating flow rate detection means, FIG. 5 is an explanatory diagram of a fluid circuit showing a second embodiment of the invention, and FIG. 6 is a diagram of a fluid circuit showing a third embodiment of the invention. An explanatory diagram, FIG. 7 is an explanatory diagram showing the operation of the operating flow rate detection means, and FIG.
+] [II] is a sectional view showing the switching operation of the switching valve,
FIG. 9 is an explanatory diagram of a fluid circuit showing a fourth embodiment of the present invention, FIG. 10 is a front view showing an external controller, and FIG. 11 is a partially cutaway perspective view showing a flow meter. 1... Jig for workpiece installation, 6... Operating cylinder, 8
...Clamp claw, 20.. Operating flow rate detection means, 22.
...flow m 1i1' (it cylinder, 23... detector, 24 - leak compensation means, 27... stopper as adjustment member, 44... fluid h- [hydraulic motor as motor, 45 - counter, Q ...Fluid supply source, ~■ Workpiece,

Claims (9)

[Claims] (1) In a workpiece clamping device in which a working cylinder that drives a clamp claw that clamps a workpiece is installed on a workpiece mounting jig, the working cylinder's working flow rate is connected to a fluid circuit connecting the working cylinder and a fluid supply source. A work clamping device characterized by being provided with an operating flow rate detection means for detecting. (2) The work clamp device according to claim 1, wherein the operating flow rate detection means includes a flow metering cylinder connected to a fluid circuit. (3) The work clamp device according to claim 2, wherein the flow metering cylinder is provided with a return cylinder. (4) The work clamp device according to any one of claims 1 to 3, further comprising a leak compensation means for compensating for leaks occurring in the operating cylinder and the fluid circuit. (5) The leak compensation means is characterized in that it includes a valve that is mechanically opened by movement of a predetermined stroke of the piston rod of the flow metering cylinder, and supplies the working fluid from the fluid supply source from the flow metering cylinder to the working cylinder. A work clamp device according to claim 4. (6) The leak compensation means includes a solenoid valve that is opened by a signal from the operating flow rate detection means, and supplies working fluid from the fluid supply source from the flow metering cylinder to the operating cylinder. Work clamping device described in section. (7) The work clamping device according to any one of claims 2 to 6, wherein the flow metering cylinder is provided with an adjusting member for setting a necessary flow rate for operating the actuation cylinder. (8) A first feature in which the operating flow rate detection means includes a flow metering cylinder, a detector that outputs an electric signal every time the cylinder strokes, and a counter that counts the electric signals from the detector. Work clamping device described in section. (9) The operating flow rate detection means includes a fluid pressure motor provided in the fluid circuit, a detector that outputs an electric signal proportional to the amount of rotation of this motor, and a counter that counts the electric signal from this detector. A work clamping device according to claim 1, characterized in that: