JPH11320474A - Holding device with claw position detecting mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense with adjustment of a sensor, to prevent trouble, and to shorten the working time required for the rearrangement by forming a holding device having a function of highly precisely detecting the position of a claw in a whole stroke. SOLUTION: A core 8 attached to a piston 4 reciprocating by a fluid pressure reciprocates the center of a coil so as to change voltage V1, V2 and consequently change the difference between V1, V2, and the output voltage difference changed by the position of the core 8 is processed as linear analog data. The analog voltage outputted by differential transformer is inputted in CPU as a digital voltage via an A/D converter to be operated in the CPU, and converted into dimension data. In robots and carrier devices required to be commonly used for multiple types, the dimension data matching a plurality of works are memorized in the CPU so that the manhour required for the rearrangement in changing a work can be reduced so as to shorten the time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid pressure gripping device having a function of detecting the position of a nail.

[0002]

2. Description of the Related Art In a conventional fluid pressure gripping device, a permanent magnet is mounted on a piston portion which reciprocates by fluid pressure in order to check the open end and closed end of a claw or to check the gripping of a work. A method of detecting and outputting the magnetic force of a permanent magnet mounted on a sensor using a sensor using a magnetoresistive element has been adopted.

[0003] When the conventional detection method described above is used in a transfer line that requires multiple types or a gripping device attached to the tip of a robot, it is necessary to adjust the position of the sensor every time the setup is changed. Needs considerable time to.

As a method of eliminating the time for sensor adjustment at the time of setup change, a method such as using a plurality of sensors is used. However, a plurality of sensors are required, so that the cost is increased and a space for mounting the plurality of sensors is secured. Required.

Further, in the case of a conventional sensor using a magnetoresistive element, since the operating width of the sensor is wide, a long cylinder stroke is required to arrange a plurality of sensors, and the sensor is moved to a small gripping device having a short cylinder stroke. Can not be installed, there is a problem that the position of the sensor must be adjusted at the time of setup change, a lot of man-hours are required, and it is not suitable for high-precision detection by the sensor.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a gripping device used in a transfer device and a robot which need to be used for many types of products, and has a function capable of detecting a position of a nail with high accuracy in all strokes. An object of the present invention is to provide a gripping device, which eliminates adjustment of a sensor at the time of setup change, prevents troubles due to improper adjustment, and shortens the work time required for setup change.

[0007]

According to the present invention, there is provided a gripping device comprising a driving unit having a piston reciprocating by hydraulic pressure and a slide unit having a master jaw opening and closing. In the above, linear analog data output from a differential transformer built in the cylinder is taken as digital data through an A / D converter and taken into the CPU, and the taken digital data is processed by the arithmetic function in the CPU as a unit of length. To output linear dimensional data converted to length units for all strokes, and to create and store a storage area in the CPU and the linearly output dimensional data. Set up robots and transfer lines that flow various types of workpieces using multiple arbitrary dimension data To allow shared by Enashi.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described.

This embodiment comprises a drive unit having a cylinder 3 and a slide unit having a conversion unit for converting a reciprocating motion of a piston 4 into an opening and closing motion of a pair of claws 1. The piston 4 is inserted into the cylinder 3. Then, reciprocating motion is performed by fluid pressure.

The reciprocating motion of the piston 4 is arranged so as to be symmetrical with respect to the piston 4 and is moved in parallel in a direction perpendicular to the reciprocating motion direction of the piston 4 by a cam 5 rotating about a fulcrum shaft 6. In a parallel hand having a pair of claws 1 arranged, a primary coil 11 is wound around the outer periphery of a cylindrical resin case 10, and two secondary coils 12, 13 are wound thereon to form a differential transformer. The differential transformer is inserted into the cylindrical protective case 9 and molded with a molding material between the resin case 10 and the protective case 9 in order to prevent foreign matter such as dust from seeing inside the case.

[0011] A differential transformer is inserted into an insertion hole formed in the center of the cylinder cover A14, and the cylinder cover A is inserted.
14 and the cylinder cover B15, and the cylinder cover is fixed to the cylinder 3.

The piston 4 is provided with a concave portion for preventing interference with a differential transformer projecting from the cylinder cover during reciprocating operation due to fluid pressure, and a brass pin having a core 8 attached to the tip at the center thereof. 7 is press-fitted and follows the piston 4 to reciprocate around the center of the differential transformer.

A sine wave voltage is applied to the primary coil 11 side of the differential transformer, one of the two secondary coils 12 and 13 is connected in the same way, and the other is connected separately, and the two secondary coils are connected. A rectifier is connected to an outlet of the rectifier to convert a sine wave voltage into a DC voltage, and take out a voltage outputted from the rectifier, a difference between V1 and V2, as an output.

In this embodiment, the voltages V1 and V2 change as the core 8 attached to the piston 4 reciprocating by the fluid pressure reciprocates around the center of the coil, and accordingly the difference between V1 and V2 also changes. The voltage difference that varies depending on the position of the core 8 and is output is processed as linear analog data.

The analog voltage output from the differential transformer is passed through an A / D converter, taken into the CPU as a digital voltage, processed in the CPU, and converted into dimension data.

The arithmetic processing in the CPU performs the arithmetic operation in accordance with the operation of the hand and can always output linear data. Further, the error caused by the claw shape can be converted into accurate dimensional data by correcting the arithmetic processing. .

As a method of outputting data from the CPU to the outside, N is compared with data storage NO and a matched NO is output.
Select and use the O output method and the method of outputting the internal dimension data as hexadecimal BIN type data.

In this embodiment, the parallel hand has been described. However, the present invention is not limited to the parallel hand only, but may be applied to all devices in which the driving unit performs a linear motion, such as a fulcrum hand, a chuck, a slide unit, and a cylinder. Can be deployed.

[0019]

According to the present invention, highly accurate and linear position detection can be performed within the entire stroke of the claw.
In addition, a storage area is provided in the CPU to provide a gripping device capable of storing a plurality of arbitrary dimension data, so that in a robot and a transfer device that need to be used for a variety of types, dimension data corresponding to a plurality of workpieces is stored in the CPU. By doing so, it is possible to respond to each work without changing the work like the type using the conventional magnetoresistive element at the time of changing the work, so that the man-hour required for the changeover and the time are shortened Can do things.

Further, in the conventional gripping device, the operating end can only be confirmed by a sensor using a magnetoresistive element or the like. However, the gripping device of the present invention can convert linear data by a differential transformer into a unit of length in a CPU, and can grip a workpiece with a nail. , It is possible to perform high-precision dimensional measurement and workpiece discrimination, so that there is no need to provide a measuring and discriminating device, and the size and cost of the device can be reduced.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a gripping device.

FIG. 2 is an enlarged sectional view of a main part showing a configuration of the differential transformer according to the embodiment.

FIG. 3 is an explanatory diagram showing a data output path.

FIG. 4 is a basic configuration diagram of a differential transformer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Claw 2 Body 3 Cylinder 4 Piston 5 Cam 6 Support shaft 7 Brass pin 8 Core 9 Protective case 10 Resin case 11 Primary coil 12 Secondary coil A 13 Secondary coil B 14 Cylinder cover A 15 Cylinder cover B

Claims (3)

[Claims] In a gripping device having a drive unit having a piston reciprocating by fluid pressure and a pair of master jaws reciprocating by a reciprocating motion of the piston, a linear output by a differential transformer incorporated in the cylinder. A gripping device with a position detecting function, which is capable of detecting a nail position with high accuracy based on simple analog data and storing the nail position data. 2. Analog data output by a case in which a primary coil and a secondary coil are formed inside and arranged inside a cylinder, and analog data output by a movable core attached to a piston and reciprocating in the case following the piston. A digital data is passed through a / D converter, is taken into the CPU, and the data is converted into a unit of length by an arithmetic function in the CPU in every stroke of the gripping device. 1. A gripping device with a function of detecting the position of a nail. 3. A data storage area is created in the CPU, and a plurality of dimension data can be stored. The input data to the CPU is compared with the stored data, and the matched data is stored in the CPU. 2. The gripping device according to claim 1, wherein the gripping device can output to a device.