JPH0337648B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a position adjustment device for mounting a position detector for detecting the movement of a piston at a desired optimum stopping position of the piston in a fluid pressure cylinder.

Fluid pressure equipment, especially pneumatic equipment, is becoming increasingly popular. The main reason for this is that it is suitable for miniaturization, does not cause pollution, and is economical. Among these, cylinders are widely used as driving devices, that is, as actuators. As you know,
The cylinder basically consists of a tube, a head cover that fits into the tube, a rod cover, and a piston that moves inside the tube. However, the tube itself, for example,
Since the tube is made of a lightweight metal tube such as aluminum, it is extremely difficult to directly confirm that pressure fluid is introduced into the tube and the piston reciprocates. That is, once the position of the piston within the tube of the cylinder is confirmed, in fact,
It becomes possible to infer whether the cylinder concerned or other equipment driven by this cylinder is functioning normally.

In order to achieve such a purpose, the applicant has attached a permanent magnet to the piston constituting the cylinder, and has installed magnetic sensors near both outer ends of a tube that accommodates the piston so that it can reciprocate. At the same time, a light emitting element is connected to the output side of the magnetic sensor, and the magnetic field of the permanent magnet that is displaced as the piston moves is detected by the magnetic sensor, thereby lighting up the light emitting element and making it visible from the outside. At the same time, we developed a piston motion detection device that outputs a detection signal, and this has come to be widely adopted in various factories.

However, the device is constructed in such a way that it is possible to simply detect whether the piston is reciprocating or not, so that the piston is reciprocated to the desired proper position and then It is not possible to detect a state in which the state has shifted to the return operation.

Such a state will be explained with reference to the drawings. That is, the cylinder 2 shown in FIG. roads are connected. Note that reference symbols A to E shown in the figure indicate areas into which the chamber within the cylinder 2 is divided.

In this case, it is optimal for the piston 4 to be located within the region C at a certain stage of the work process,
In addition, even if the piston 4 is located in the region B or D, it is allowed. That is,
In a given working process, region C corresponds to the optimum position of piston 4, and regions B, C correspond to permissible positions of piston 4. Therefore, in a predetermined work process, if the piston 4 is located in region A or region E outside the permissible range, the desired work cannot be accomplished.

In such a case, generally, from the viewpoint that it is sufficient to detect that the piston is located at least at the optimum position shown in area C, a magnetic sensor is provided on the outer peripheral surface of the cylinder 2 corresponding to area C, and , a method is adopted in which a permanent magnet is embedded in the piston itself and the movement of the piston 4 is detected by the magnetic sensor.

However, in such a system, the piston 4
Even if the piston 4 is located in the region B or D, it is impossible to detect whether the piston 4 is stopped at the optimum stop position in order to perform a detection operation. In addition, if there is a difference between the mounting position of the magnetic sensor and the actual stopping position (optimum stopping position) of the piston 4, the piston 4 may stop outside the allowable range of the optimum stopping position due to the reciprocating movement of the piston 4. On the other hand, due to the deviation of the magnetic sensor from the optimum piston stop position, the magnetic sensor cannot actually detect this even if the piston 4 stops at the optimum stop position. expose flaws. Furthermore, a method may be considered in which magnetic sensors for detecting the movement of the piston 4 are provided corresponding to the regions B, C, and D, respectively.
In such a case, at least three magnetic sensors are required, resulting in an increase in installation space and an inconvenience that the device as a whole must be extremely expensive.

The present invention has been made in order to overcome all of the above-mentioned disadvantages, and includes providing a position adjustment device for a position detector for detecting the stop position of a piston in a fluid pressure cylinder. For mounting a position detector in a fluid pressure cylinder configured to position and fix the position detector at the detected optimal stopping position of the piston, and constantly displaying whether or not the position detector has reached the optimal stopping position of the piston. The object of the present invention is to provide a position adjustment device.

In order to achieve the above object, the present invention fixes a magnetic body made of a permanent magnet to a part of the piston, and on the other hand, a piston position detection device including a magnetic sensor and a display part on the outer periphery of a tube made of a non-magnetic body. The magnetic sensor of the piston position detection means and the tip of the probe are positioned on a virtual circle perpendicular to the axial direction of the tube, and the magnetic flux of the permanent magnet is detected by the tip of the probe. The present invention is characterized in that it is configured to detect the position of the piston within the cylinder.

Next, preferred embodiments of the position adjustment device according to the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 2, reference numeral 10 indicates a cylinder, and this cylinder 10 is supported by angular supports 12a and 12b fixed to a base (not shown). The supports 12a and 12b have one end attached to a rod cover 14 and a head cover 16, respectively, and are attached to a tube 1 constituting the cylinder 10.
8 is held between the rod cover 14 and the head cover 16. That is, a plurality of tie rods 20 are bridged between the rod cover 14 and the head cover 16, and the tie rods 20 tighten the rod cover 14 and the head cover 16 to firmly hold the tube 18 made of a non-magnetic material. The cylinder rod 24 is exposed to the outside through the bush 22 from a hole drilled in the approximate center of the rod cover 14, and inside the tube 18, the piston 26 fixed to the tip of the cylinder rod 24 has its outer circumferential wall. A ring-shaped permanent magnet 28 is fitted into the groove formed in the groove.

On the other hand, belts 30a and 30b made of non-magnetic material are attached to the rod cover 14 side and the head cover 16 side of the tube 18.
Magnetic detection means 32a and 32b are fixed to 30b. That is, both ends of the attachment member 34a made of a non-magnetic material are secured using the holes formed at both ends of the belt 30a. The mounting member 34
a has a screw 36a approximately in the center thereof, and the tip of the screw 36a is connected to the housing 3 as shown in FIG.
Facing 8a. It is preferable that this housing 38a is also made of a non-magnetic material.

A display window 4 made of a transparent material is provided at the top of the housing 38a.
0a is attached, and this display window 40a is attached to the housing 3.
It is formed to bulge slightly upward from 8a. moreover,
A hole 42a is formed in the side of the casing 38a, and a conductive wire 46a connected to a printed circuit board 44a containing an electric circuit disposed inside the casing 38a faces the hole 42a. A light emitting element, ie, an LED 48a, is disposed on the upper surface of the printed circuit board 44a so as to face the display window 40a, and a sensor 50a made of a magnetoresistive element is fixed and held below the printed circuit board 44a. Needless to say, the printed circuit board 44a receives the output signal of the sensor 50a and also includes the LED 48.
A control circuit for causing light to emit light is formed. Furthermore, one corner of the casing 38a is cut out, and a hole 52a is formed in the corner, pointing toward the tube 18 (see FIG. 4).

In the device of the present invention, a probe 54a is attached through this hole 52a. Probe 54a
includes a casing 56a, and this casing 56
a is attached to the magnetic detection means 32a by a leaf spring 58a extending from its top. That is, as can be easily understood from FIG. 4, the leaf spring 58a is configured such that its upper end is curved and its tip is once lowered, and the bent portion 60a, 62a.

On the other hand, a Hall element 64a is disposed on the surface of the casing 56a facing the tube 18, and the output of the Hall element 64a is taken out to the outside via a conductor 66a. Configure it to output to the device. Therefore, if the tip of the leaf spring 58a faces the hole 52a defined in the housing 38a, the bent portions 60a, 62a will come into pressure contact with the wall of the housing 38a within the hole 52a. Therefore, it is easily understood that the Hall element 64a is located as close as possible to the tube 18 made of a non-magnetic material.

In this case, the main body of the probe 54a,
That is, the Hall element 64a is connected to the tube 18 that constitutes the cylinder 10, as shown in FIG.
A circle A imagined to be orthogonal to the axial direction of
It is more preferable to arrange it at one point above, since it becomes possible to detect the magnetic field lines of the permanent magnet 28 together with the sensor 50a. On the other hand, the same configuration as the magnetic detection means 32a is adopted on the belt 30b side, and therefore, b is added to the reference numeral indicating the component of the magnetic detection means 32a, and detailed explanation thereof will be omitted.

The position adjustment device for mounting a position detector in a fluid pressure cylinder according to the present invention is basically constructed as described above, and its operation and effects will be explained next.

First, the cylinder 10 is connected to a solenoid valve (not shown) via a fluid conduit, and compressed air is fed from the fluid conduit into the tube 18 through a port (not shown) of the cylinder 10. As a result,
The piston 26 is moved to the tube 1 by this compressed air.
8. Displacement operation is performed within 8. Therefore, first, the piston 26 is stopped at one end of the tube 18.
Next, when the sensor 50a moves a predetermined distance and approaches the piston 26, the LED 48a lights up. At the same time, the belt 30a is relaxed and the magnetic detection means 3
2a, that is, the sensor 50a is moved along the tube 18 toward the one end. As a result, the probe 54a that is attached to the hole 52a of the magnetic detection means 32a is connected to the permanent magnet 28 of the piston 26.
As the magnetic flux approaches , the magnetic flux is detected under the action of the Hall element 64a. Therefore, depending on the magnitude of the magnetic flux density detected by the Hall element 64a, an LED 48a constituting a display device (not shown) is turned on, and the magnetic flux density is electrically visually recognized to the outside in an analog manner.

Therefore, when the sensor 50a reaches right above the permanent magnet 28 of the stopped piston 26, the maximum number of display device LEDs 48a lights up due to the detection of the maximum magnetic flux density. This position is the optimum stopping position for the piston 26. When the optimum stop position is detected, the belt 30a is tightened again, and when the piston 26 is subsequently driven in the normal state, the LED 48a will indicate that the piston 26 has reached the optimum stop position. Similarly, such positioning is performed on the magnetic detection means 32b side as well.

By the way, in a fluid pressure cylinder, the reciprocating range of the piston is not always fixed. In other words, the stroke of the piston 26 may be changed intentionally or due to changes in the magnitude of the load moved by the cylinder rod 24, fluctuations in the fluid pressure supplied to the cylinder 10, or deterioration of the quality of the cylinder 10 itself, or due to aging. It is not uncommon for it to be changed due to changes, etc. In such a case, it may be necessary to newly set the optimum position.

In such cases, the device of the present invention makes a significant contribution. That is, when attempting to newly detect the optimum stopping position of the piston 26, the belts 30a, 30b
is relaxed and the magnetic detection means 32a, 32b are moved along the tube 18 again. Therefore, sensor 5
0a grasps the permanent magnet 28 of the piston 26 at the optimum stop position, and the Hall element 64a grasps the permanent magnet 28 at the optimum stop position.
The maximum magnetic flux is detected directly above 8. Therefore, the magnetic detection means 32a set at this position detects the reciprocating movement of the piston 26 under this new optimum stop position. Of course, the magnetic detection means 3
The same applies to the 2b side. Note that the probes 54a, 5
4b connects the leaf springs 58a, 58b to the housings 38a, 38.
It can be easily removed by pulling it out from the holes 52a and 52b of b. Therefore, the probes 54a, 54b do not need to be attached to the cylinder 10 all the time, but only need to be attached to the magnetic detection means via the leaf spring, for example, only during maintenance. Furthermore, the Hall element 64a
If the output of the Hall element 64 is connected to a digital display (not shown) via a conductor 66a,
Since the magnitude of the magnetic lines of force of the permanent magnet 28 detected by a can be displayed on the digital display device (not shown), the optimum stopping position of the piston 26 can be easily detected.

As described above, according to the present invention, it is possible to accurately grasp the optimum stopping position of the piston in the cylinder. Moreover, since the probe need only be attached to the cylinder for maintenance management, the overall cost is low and there is an advantage that it is extremely economical.

Although the present invention has been described above with reference to a preferred embodiment, the present invention is not limited to this embodiment. It is possible to make various improvements and changes in design without departing from the gist of the present invention, such as the fact that the same objective can be achieved even by detecting only one stroke end of the piston. Of course.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram of a fluid pressure cylinder according to the prior art, Fig. 2 is a partially cutaway perspective explanatory diagram of a cylinder incorporating a position adjustment device according to the present invention, and Fig. 3 is a magnetic field for detecting the position of a piston. 4 is an exploded perspective view when the probe is installed in the magnetic detection means shown in FIG. 4, and FIG. FIG. 3 is a perspective explanatory view showing a state in which the probe is in pressure contact with a tube constituting a cylinder. 10...Cylinder, 14...Rod cover, 1
6...Head cover, 18...Tube, 20...
...Tie rod, 24...Cylinder rod, 26...
...Piston, 28...Permanent magnet, 30a, 30b
...belt, 32a, 32b...magnetic detection means,
34a, 34b...Mounting member, 38a, 38b...
...Housing, 40a, 40b...Display window, 46a, 4
6b...Conducting wire, 54a...Probe, 56a...
Casing, 58a...plate spring, 64a...Hall element, 66a...conducting wire.

Claims (1)

[Claims] 1. A magnetic body made of a permanent magnet is fixed to a part of the piston, while a piston position detection means including a magnetic sensor and a display section is movable on the outer periphery of a tube made of a non-magnetic material. The magnetic sensor of the piston position detection means and the tip of the probe are positioned on a virtual circle perpendicular to the axial direction of the tube, and the magnetic flux of the permanent magnet is detected by the tip of the probe to detect the magnetic flux inside the cylinder. 1. A position adjustment device for mounting a position detector in a fluid pressure cylinder, characterized in that the device is configured to detect the position of a piston. 2. In the device according to claim 1,
A position adjustment device for mounting a position detector in a fluid pressure cylinder, in which a Hall element is provided at the tip of the probe, and an electric signal is obtained from the magnetic flux of a permanent magnet detected by the Hall element to detect the piston position in the cylinder. . 3. A position adjusting device for mounting a position detector in a fluid pressure cylinder, in the apparatus according to claim 1 or 2, wherein the probe is detachably attached to the piston position detecting means.