JPH0381081B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a displacement sensor having a shift mechanism, which has a simple overall configuration and is miniaturized.

When various products are molded using a press or the like, a displacement sensor may be used to inspect whether the product is finished to the designed dimensions. In this displacement sensor, a measuring rod protruding from the inside of the main body is pressed against a product, and the quality of the product is inspected based on the displacement of the measuring rod.

FIG. 1 shows a conventional displacement sensor, and in this figure, 1 is a product to be tested, which is held at the top of a pedestal 2. As shown in FIG. cradle 2
A guide frame 3 is provided on the side of the holding frame 4, and supports the holding frame 4 in a horizontally slidable manner. A displacement sensor 6 is horizontally attached to the holding frame 4,
The tip of a rod 7 protruding from the cylinder 5 is attached to a part of the displacement sensor 6. A measuring rod 8 protrudes from the displacement sensor 6 and is adapted to come into contact with the product 1.

The conventional displacement sensor 6 having such a configuration operates the cylinder 5 to protrude the rod 7, moves the displacement sensor 6 forward, and places the tip of the measuring rod 8 on the product 1.
press against. When the product 1 is moved, the measuring rod 8 moves forward or backward depending on the finished state of the product 1. The manufacturing accuracy of the product is detected based on this displacement. In this case, the measuring rod 8 can move forward and backward within a certain range with respect to the main body of the displacement sensor 6,
Since the tip of the measuring rod 8 at approximately the center of the range is the normal position of the product 1, and the measuring rod 8 is urged to protrude by a spring,
The tip of the measuring rod 8 gets in the way, making it difficult to set and take out the product 1.

For this reason, the displacement sensor 6 is set at the product setting position.
It is necessary to separately provide a cylinder 5 for changing the position between the take-out position and the measurement position, resulting in a problem that the overall structure becomes complicated and large.

The object of the present invention is to provide a displacement sensor having a shift mechanism that solves these problems.

Next, an embodiment of the present invention will be described with reference to FIG. 2. Reference numeral 9 denotes an outer cylinder, which is supported horizontally by a holding frame 10. As shown in FIG. An air supply port 11 is provided at the base end of the outer cylinder 9, and is connected to an air supply source (not shown) to supply or remove compressed air from the base end side into the outer cylinder 9. It's getting old. The proximal end side of an inner cylinder 13 having a piston 12 at its proximal end is fitted inside the outer cylinder 9,
The tip of the inner tube 13 protrudes from the tip of the outer tube 9, and the piston 12 can slide in close contact with the inner wall of the outer tube 9, forming a fluid pressure cylinder. 14 is a thrust liner that improves the sliding movement of the piston.

There are two stepped portions 15, 1 near the tip inside the outer cylinder 9.
6, and a coil spring 17 is interposed between the step portion 15 on the distal end side and the piston 12 in a slightly compressed state. With this, the inner cylinder 1
3 is always urged to be drawn into the outer cylinder 9. A hollow differential coil 18 is fixed inside the inner cylinder 13 so as to align with the axis of the inner cylinder 13 . A core 19 made of a magnetic iron core is fitted inside the differential coil 18 so that it can freely move forward and backward within a certain range.

A proximal end of a measuring rod 20 having a length protruding from the distal end of the inner cylinder 13 is connected to the distal end of the core 19 via a rod 21 . The proximal end of the measuring rod 20 is located within the inner cylinder 13 and is provided with a flange 22. A coil spring 23 is inserted between the flange 22 and the end of the differential coil 18 in a slightly compressed state. has been done. As a result, a force is constantly applied to the measuring rod 20 in a direction that causes the tip side to protrude from the inner cylinder 13. 24 is a thrust liner that allows the measuring rod 20 to slide smoothly; 25 is a differential coil 1;
This is the lead wire outlet from 8. and core 19
The measuring rod 20 when is in the center of the differential coil 18
The tip position of is set to the normal position of product 1.

This displacement sensor configured in this way is used as follows.

First, the inner cylinder 13 is retracted into the outer cylinder 9 as shown in FIG.
The product 1 is mounted on the pedestal 2 using a reference pin or the like in a retracted state so as not to come into contact with the product 1. Next, compressed air is supplied from the air supply port 11 to apply this air pressure to the piston 12. As a result, the inner cylinder 13
compresses the coil spring 17 and moves to the left,
As shown in the figure, the piston 12 protrudes from the outer cylinder 9 until it comes into contact with the stepped portion 16. As a result, the tip of the measuring rod 20 comes into contact with the measuring surface of the product 1, compressing the coil spring 23, and causing the measuring rod 20 to be slightly retracted into the inner cylinder 13.

In this case, if a current of a predetermined magnitude and direction is passed through the differential coil 18, the current value will change depending on the impedance value, which changes depending on the position of the core 19, which is displaced with the measuring rod 20. . By capturing this current value change, processing it appropriately, and displaying it digitally, the position of the product 1 is confirmed and the measurement is completed.

When the measurement is completed, the compressed air in the outer cylinder 9 is removed, and the inner cylinder 13 is drawn into the outer cylinder 9 by the force of the coil spring 17. By this, measuring rod 2
The tip of the measuring rod 20 is separated from the product 1, and at the same time, the measuring rod 20 is returned to the protruding state shown in FIG. 2 by the force of the coil spring 23. In this state, product 1 is taken out.

Since this invention is configured as described above, it has the following effects.

The displacement sensor and the cylinder, which were conventionally provided separately, are now integrated, and the displacement sensor itself functions as a so-called piston rod, so the overall length is shortened, and the distance between the outer cylinder 9 and the inner cylinder 13 is reduced. Since it is only necessary to have a gap large enough to accommodate the spring, the outer diameter is also small, resulting in an overall structure that is simple, compact, and advantageous in terms of cost.

Furthermore, when setting or taking out a product to be measured, the core 19 and measuring rod 20 do not need to be moved relative to the inner cylinder 13 and differential coil 18, so unnecessary movements other than measurement can be prevented. .

Further, since the sensor can be miniaturized, it is extremely easy to arrange it even when used in a measuring device for automobile parts or the like, which normally consists of a large number of displacement sensors placed close to each other.

[Brief explanation of drawings]

Figure 1 is a side view of a conventional displacement sensor.
FIG. 2 is a longitudinal sectional view of one embodiment of the present invention, and FIG. 3 is a longitudinal sectional view showing the device shown in FIG. 2 in a state of use. 9... Outer cylinder, 11... Air supply port, 12... Piston, 13... Inner cylinder, 17, 23... Coil spring, 18... Differential coil, 19... Core, 20...
...Measuring stick.

Claims (1)

[Claims] 1. A fluid pressure cylinder is formed by fitting the proximal end side of an inner cylinder provided with a piston at the proximal end into an outer cylinder, and making the tip of the inner cylinder protrude from the tip of the outer cylinder, and the inside of the inner cylinder A hollow differential coil is fixed in alignment with the axis of the inner cylinder, a core made of magnetic iron is fitted inside the differential coil so as to be movable forward and backward, and the tip of the core is fitted with the above-mentioned core. A proximal end of a measuring rod having a length protruding from the tip of the inner cylinder is coupled, a spring is further interposed inside the inner cylinder to urge the measuring rod to protrude from the inner cylinder, and An air supply port is provided on the base end side of the outer cylinder for supplying and discharging compressed air to the inside of the base end side of the outer cylinder, and inside the outer cylinder is biased to draw the inner cylinder into the outer cylinder. A displacement sensor having a shift mechanism characterized by being provided with a spring that moves.