JPH04130006U - Piston position detection mechanism - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a piston position detection mechanism that can accurately detect the piston position by disposing a magnetic resistance element at a location with the best measurement sensitivity. [Structure] A mounting member 42 is provided on the cylinder 32 at a location where the magnetic resistance element can satisfactorily detect a magnetic field. Therefore, when the magnetic resistance element detects the position as the piston 52 reciprocates, the magnetic body 5 incorporated in the piston 52
4 maximum magnetic field can be detected, and the accurate position of the piston 52 can be detected or the reciprocating movement of the piston 52 can be confirmed.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention relates to a piston position detection mechanism, and more specifically, to a piston position detection mechanism that configures a fluid pressure circuit. A sensor that detects the position of the piston inside the cylinder is connected to a magnetic sensor fixed to the piston. The present invention relates to a piston position detection mechanism that is attached to a position where the magnetic field strength of a magnetic body is maximum.

0002

[Conventional technology]

Conventionally, fluid pressure cylinders have been used to transport goods and perform predetermined tasks. When the piston reciprocates within the cylinder, it reaches a predetermined position within the cylinder. It is necessary to check whether there are any. Therefore, depending on the strength of the magnetic field, the electrical resistance The cylinder is fixed at the predetermined position using a magnetoresistive element whose By embedding a permanent magnet in the piston, the piston moves back and forth to the predetermined position. When the piston passes through the piston, the position of the piston is detected by the change in resistance of the magnetic resistance element.

0003 Figures 3 and 4 show a cylinder equipped with a piston position detection device according to the prior art. vinegar. The position detection device 2 attached to this cylinder basically consists of a magnetic field detection circuit section 4. and a piston position detection unit (for example, a sequencer) 6. Inside cylinder 8 A magnetic material 12 containing magnetic powder is embedded in a ring shape in a piston 10 that reciprocates. The magnetic body 12 and the magnetic field detection circuit section 4 are within a certain distance, that is, the distance between the magnetic body 12 and the magnetic field detection circuit section 4 is When the piston 10 is within the detection range F, the position detection device 2 detects that the piston 10 is at a predetermined position. It can be determined that the robot is in the same position or is performing normal reciprocating motion.

0004 In this case, in the prior art described above, the outer side of the cylinder 8 is connected to the position detection device 2. A bulging part 14 is formed in the center of the groove 11 formed in the front part to extend in the axial direction. A mounting groove 16 is defined in the bulge 14 extending in the longitudinal direction. And the above Fit the nut 18 into the desired position of the groove 16, and attach the mounting member 20 to this nut 18. Stack them and tighten them with bolts 22 and nuts 24. The mounting member 20 includes a magnetic field detection circuit section. 4 are integrally fixed.

[0005]

[Problem that the idea aims to solve]

However, in the above-mentioned prior art, the mounting groove 1 bulges on the outer surface of the cylinder. 6 is disposed substantially in the center of the groove 11, so that it cannot be incorporated into the magnetic field detection circuit section 4. In this case, the position of the sensor 26, which is a magnetic resistance element, is displaced. In other words, this This causes the position of the sensor 26 to deviate from the position where the maximum magnetic field strength is detected, causing the There is a possibility that the position of the stone 10 cannot be detected satisfactorily. In other words, as shown in Figure 4 As such, the position of the sensor 26 of the magnetic field detection circuit section 4 is shifted from the location where the magnetic field is strongest. Even if the piston 10 reciprocates, the strength of the magnetic field reaching the sensor 26 is small. This makes it difficult for the magnetic field detection circuit section 4 to detect the position of the piston 10.

[0006] The present invention has been made to overcome the above-mentioned disadvantages, and is a magnetic field detection circuit. At any position along the longitudinal direction of the cylinder, and at a magnetically fixed position on the piston. Mounted at the position that detects the maximum magnetic field of the body, thereby allowing accurate piston position detection The purpose of the present invention is to provide a piston position detection mechanism that is capable of detecting piston position.

[0007]

[Means to solve the problem]

In order to achieve the above object, the present invention provides a fluid pressure cylinder constituting a fluid pressure circuit. A magnetic material is fixed to the piston in the cylinder, and the strength of the magnetic field of the magnetic material causes the piston to move. A piston position detection mechanism that detects a position, A magnetic field detection part is attached to the side of the cylinder body along the axial direction of the cylinder, and The magnetic sensor that constitutes the magnetic field detection section detects the maximum magnetic field level of the magnetic material attached to the piston. It is characterized by being fixed according to the position.

[0008]

[Effect]

In the piston position detection mechanism according to the present invention, the piston position detection mechanism is located outside the cylinder. Position the sensor in a suitable position to detect the maximum magnetic field of the magnetic material embedded in the This allows the position of the piston to be accurately detected and It is possible to check whether the performance of the reciprocating motion has been achieved or not.

[0009]

【Example】

A preferred embodiment of the piston position detection mechanism according to the present invention will be described, and the accompanying drawings will be explained. This will be explained in detail below with reference to .

0010 In FIG. 1, reference numeral 30 indicates a piston position detection mechanism according to the present invention. Before The piston position detection mechanism 30 is located at the outer center in the longitudinal direction of a cylinder 32 having a rectangular cross section. Concave portions 32a, 32b and 32c are defined in the portions, respectively, which expand outward. Na Since these recesses 32b and 32c have substantially the same shape as the recess 32a, This recessed portion 32a will be explained in detail below.

[0011] A stepped portion 34 is formed in one corner of the recessed portion 32a, and a cylinder is formed in the stepped portion 34. The groove 36 extends in the longitudinal direction of the groove 32 . The groove 36 is formed as shown in FIG. In addition, it is slightly deviated from the center of the recess 32a. Attach a nut to a predetermined position in the groove 36. 38, screw the tip of the bolt 40 into this nut 38, and The mounting member 42 is fitted therein. The mounting member 42 is integral with the magnetic field detection section 44. , the magnetic field detection section 44 includes a magnetic sensor at the bottom of a casing 46 incorporating a detection circuit (not shown). 48. A nut 50 is screwed onto the upper part of the mounting member 42, and a washer 53 is attached. The mounting member 42 is firmly fixed through the mounting member 42. Given this configuration, the above The magnetic sensor 48 is located at the center of the recess 32a and at the thinnest part of the cylinder 32. In other words, it is placed at the position closest to the magnetic body 54 that fits into the piston 52. It is easy to understand that

0012 Note that since the recesses 32b and 32c also have steps and grooves, magnetic field detection is possible. The portion 44 can be selectively positioned in any of the recesses 32a to 32c. here In FIG. 2, reference numerals 56a and 56b are used to supply pressure fluid to the cylinder 32. Indicates the port for

[0013] Therefore, the operation of the piston position detection mechanism configured as described above is explained below. explain.

[0014] First, pressure is alternately applied from the ports 56a and 56b via a pressure fluid conduit (not shown). When fluid is introduced into the cylinder 32, the piston 52 performs a displacement movement. At this time The ring-shaped magnetic body 54 fitted to this piston 52 is made of a non-magnetic material. The magnetic body 54 slides inside the cylinder 32 together with the piston 52. The magnetic field is detected by the magnetic sensor 48 of the magnetic field detection section 44. This magnetic sensor As mentioned above, 48 is the thinnest part of the cylinder 32, that is, the cylinder To be fixed at the closest maximum magnetic field position detection site in the radial direction of 32 , it becomes possible to easily detect the sliding displacement of the piston 52. Therefore, this implementation According to the example, it is possible to accurately detect the position of the piston 52, and from this point of view, This is a case where a magnetic body 54 that generates extremely weak lines of magnetic force is attached to the piston 52. Even if the magnetic field is present, it is possible to easily detect the presence or absence of the magnetic field and confirm the piston position. Become. Moreover, if the cylinder 32 itself is configured as described above, it will be easier to pull out the cylinder 32 itself. Or the effect of making extrusion molding easier than conventional methods and reducing material costs. is obtained.

[0015]

[Effect of the idea]

According to the present invention, as described above, a magnetic sensor for detecting the piston position is used. The piston is installed at the position where the magnetic flux of the magnetic material is maximum. Therefore, the position of the piston can be detected extremely easily, and conventional piston position detection is Compared to a device, when trying to detect the piston position using the same magnetic field lines, This provides the effect that the magnetic material itself to be deposited can be miniaturized.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of a piston position detection mechanism and cylinder according to the present invention.

FIG. 2 is a perspective explanatory view of the piston position detection mechanism and cylinder shown in FIG. 1;

FIG. 3 is a longitudinal cross-sectional view of a piston position detection device according to the prior art.

FIG. 4 is an explanatory longitudinal sectional view of the installation of a piston position detection device according to the prior art.

[Explanation of symbols]

30...Piston position detection mechanism 32...Cylinder 34...Step part 42...Mounting member 48...Magnetic sensor

Claims (1)

[Scope of utility model registration request] 1. A piston position detection mechanism that fixes a magnetic material to a piston in a fluid pressure cylinder constituting a fluid pressure circuit and detects the position of the piston based on the strength of the magnetic field of the magnetic material, the mechanism comprising: A magnetic field detection section is attached to the side surface along the axial direction of the cylinder, and the magnetic sensor constituting the magnetic field detection section is fixed in correspondence with the maximum magnetic field position of the magnetic body attached to the piston. Piston position detection mechanism.