JPH0653914U - Piston position detector for fluid pressure cylinder - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a piston position detection device for a fluid pressure cylinder that is free from the risk of malfunction. [Structure] The direction of the magnetic pole of a magnet 12 attached to a piston 11 is set to a direction substantially orthogonal to the moving direction of the piston 11, and a position sensor 15 that detects a magnetic field of the magnet and outputs a signal is used. It is attached to the cylinder tube 13 so as to be parallel to the direction of the magnetic lines of force. Since the magnetic force lines of the magnet 12 are in the direction orthogonal to the moving direction of the piston 11, the magnetic force lines that cause the position sensor 15 to malfunction do not act.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a piston position detecting device for a fluid pressure cylinder.

[0002]

[Prior art]

 As shown in FIG. 10, a piston position detection device for a fluid pressure cylinder is provided with a magnet 2 on a piston 1 of a fluid pressure cylinder and a position sensor 3 attached to the cylinder for detecting a magnetic field of the magnet 2 and outputting a signal. , Already known. Since the magnetic poles of the magnet 2 in the known position detecting device are arranged in the direction parallel to the moving direction of the piston 1, the magnetic force lines thereof are as shown in FIG. On the other hand, since the position sensor 3 has directivity in sensitivity, it is necessary to mount the position sensor 3 in a direction parallel to the direction of the magnetic force line in the magnet 2, in other words, the direction in which the piston moves (the direction of the arrow in the figure).

The above-mentioned known piston position detection device has a simple structure of the magnet 2, but malfunctions if the magnetic force of the magnet 2 is too strong or if the distance between the magnet 2 and the position sensor 3 is too short. There is. This erroneous operation is because, as shown in FIG. 10, in the magnetic field lines of the magnet 2, in addition to the magnetic field lines A 1 to be detected by the position sensor 3, there are magnetic field lines B 1 and B 2 which cause the erroneous operation. For this reason, the magnet 2 needs to generate an appropriate magnetic force line with respect to the position sensor 3, which poses a problem that the material, size, and shape of the magnet are limited.

[0004]

[Problems to be solved by the device]

 The problem to be solved by the present invention is to provide a piston position detection device for a fluid pressure cylinder that does not cause a malfunction.

[0005]

In order to solve the above problems, the present invention provides a moving part such as a piston or a moving member that moves in synchronization with the piston, a fixed part such as a cylinder, and the moving part or In a piston position detection device for a fluid pressure cylinder equipped with a magnet attached to one of the fixed parts and a position sensor that detects the magnetic field of the magnet attached to the other and outputs a signal, It is characterized in that the direction of the magnetic poles is substantially perpendicular to the moving direction of the moving part, and the direction of the position sensor is substantially parallel to the direction of the magnetic force lines of the magnet. Further, in order to solve the same problem, the magnet has a ring-shaped magnet in which a plurality of magnetic poles in the radial direction are alternately magnetized in the circumferential direction and the magnetic poles in the radial direction are alternately reversed, and a magnetic pole in the width direction. A rod-shaped magnet, a magnet in which a plurality of magnet pieces having mutually opposite magnetic poles are arranged in parallel in a direction orthogonal to the direction of the magnetic pole, or a magnet having a magnetic material yoke attached to the piston side of the magnetic pole of the magnet. It is characterized by having done. Further, in order to solve the same problem, the piston position detecting device is configured such that a plurality of radial magnetic poles are magnetized in the circumferential direction by alternately arranging the magnetic poles in opposite directions, and the magnets. And a position sensor having a plurality of magnetic detectors arranged in the direction of the magnetic lines of force.

[0006]

[Action]

 When a magnet attached to one of these and a position sensor attached to the other approach, due to relative movement between a moving part such as a piston or a moving part that moves in synchronization with the piston and a fixed part such as a cylinder tube, Since the position sensor detects the magnetic field of the magnet and outputs a signal, the position of the moving part such as the piston can be detected. In this case, the direction of the magnetic pole of the magnet is set to a direction substantially orthogonal to the moving direction of the moving section, and the direction of the position sensor is set to be substantially parallel to the direction of the magnetic force lines of the magnet. Since the magnetic force lines that cause the sensor to malfunction do not act, it is possible to reliably prevent the malfunction of the position detection device.

Further, a plurality of magnetic poles in the radial direction are alternately magnetized in the circumferential direction by alternately arranging the magnetic poles in opposite directions, and a plurality of magnetic detection elements arranged in the direction of the magnetic force lines of the magnets. Since a position sensor having a part is provided, even if the ring-shaped magnet and the piston rotate relative to each other, movement of the piston or the like will be caused by one of the plurality of magnetic detection parts arranged in the direction of the magnetic force line. The position of the part can be detected.

[0008]

【Example】

 1 to 3 show a first embodiment of the present invention, in which a ring-shaped magnet 12 to be described later is attached to an outer peripheral surface of a piston 11 in the fluid pressure cylinder 10 and an outer surface of a cylinder tube 13 is attached thereto. Are attached to the sensor mounting portions 14 and 14 so as to be movable in the longitudinal direction of the tube 13, and the position sensors 15 and 15 are attached to these sensor mounting portions 14 and 14 as shown in FIG. The magnet 12 is installed so that its orientation is substantially parallel to the direction of the magnetic lines of force of the magnet 12.

The magnet 12, which is shown in detail in FIGS. 2 and 3, has its radial magnetic poles magnetized in an even numbered positions (four positions in the illustrated example) in the circumferential direction with the directions of the magnetic poles being alternately reversed. Further, it is configured as a ring-shaped radial anisotropic magnet, and is attached to the outer peripheral surface of the piston 11 so as not to rotate by an appropriate means (not shown). Therefore, as shown in FIG. 2, the flow of the magnetic force lines of the magnet 12 is substantially perpendicular to the moving direction of the piston 11 and the magnet 12 (the arrow direction in FIG. 3).

In the first embodiment described above, the direction of the magnetic pole of the magnet 12 is substantially perpendicular to the moving direction of the piston 11, and the position sensors 15 and 15 are installed substantially parallel to the direction of the magnetic lines of force of the magnet 12. As a result, since the magnetic field lines that cause the position sensors 15 and 15 to malfunction do not act, it is possible to reliably prevent malfunctions of the position detection device. If the magnet 12 is made of material, size, shape, etc. There is no restriction of.

FIG. 4 shows a second embodiment of the present invention. A position sensor 16 of the second embodiment includes a plurality of magnetic detection units 17, ... Which are installed substantially linearly in the direction of the magnetic force lines of the magnet 12. I have it. In the second embodiment, even if the piston 11 and the magnet 12 rotate relative to each other, the magnetic lines of force of the magnet 12 can be detected by any one of the plurality of magnetic detection units 17, ... There is no problem even if the piston 11 rotates relatively. In this case, the piston 11 and the magnet 12 move in a direction (direction orthogonal to the drawing) that is orthogonal to the installation direction of the magnetic detection units 17 ,. However, the position sensor 16 does not malfunction. Since the other structure and operation of the second embodiment are the same as those of the first embodiment, detailed description will be omitted.

FIGS. 5 to 7 show a third embodiment of the present invention in which the fluid pressure cylinder is a rodless cylinder 20, and the rodless cylinder 20 has a piston (not shown) along a cylinder tube 21. As shown in FIG. 7, a rod-shaped magnet 23 having a moving element 22 that moves in synchronization with the moving element 22 is attached to the moving element 22 in a direction substantially parallel to the moving direction. Have Further, as shown in FIGS. 6 and 7, the position sensors 15 1, 15 2 are installed in a direction substantially parallel to the direction of the magnetic lines of force of the magnet 23. In the third embodiment, since the magnet 23 is rod-shaped, the operating range of the position sensor 15 can be extended. Other configurations and operations of the third embodiment are the same as those of the first embodiment, and therefore detailed description will be omitted.

FIG. 8 shows another example of a magnet. This magnet 25 is obtained by arranging two magnet pieces 26, 26 having mutually opposite magnetic poles in a direction substantially orthogonal to the magnetic pole direction. It is configured.

FIG. 9 shows still another example of the magnet. This magnet 30 is constructed by attaching a yoke 31 formed of a magnetic material such as iron to the magnetic pole on the piston side of the magnet 25 shown in FIG. Is made. The magnet 30 can prevent leakage of magnetic force lines on the piston side by the yoke 31 made of a magnetic material. The attachment mode and operation of these magnets 25 and 30 to the piston 11 or the mover 22 are the same as those of the magnet 23.

[0015]

[Effect of device]

 In the present invention, the direction of the magnetic pole of a magnet attached to one of the piston of a fluid pressure cylinder or a moving element that moves in synchronization with the piston and the fixed portion of the cylinder is set to the moving direction of the moving section. Since the position sensor is installed in a direction substantially orthogonal to the above and the position sensor is installed substantially parallel to the direction of the magnetic lines of force of the magnet, malfunction of the position detecting device can be reliably prevented. Therefore, it is possible to use a magnet having an arbitrary magnetic force or size and shape. Further, since the position sensor is provided with a plurality of magnetic detection units arranged in the direction of the magnetic force lines, the magnetic force lines can be detected even when the ring-shaped magnet and the moving unit relatively rotate.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a main part of a first embodiment.

FIG. 2 is also an explanatory diagram of a magnet and a position sensor.

FIG. 3 is a vertical sectional view of the piston.

FIG. 4 is an explanatory diagram of a magnet and a position sensor according to a second embodiment.

FIG. 5 is a front view of the third embodiment.

FIG. 6 is a side view of the same.

FIG. 7 is an explanatory diagram of a magnet and a position sensor of the same.

FIG. 8 is a side view of another example of the magnet.

FIG. 9 is a side view of still another example of the magnet.

FIG. 10 is an explanatory diagram of a magnet and a position sensor of a known position detecting device.

[Explanation of symbols]

 10, 20 Fluid pressure cylinder 11 Piston 12, 23, 25, 30 Magnet 13, 21 Cylinder tube 14, 16 Position sensor 17 Magnetic detection part 18, 26 Magnet piece 22 Mover 31 Yoke

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[Procedure amendment]

[Submission date] December 2, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a main part of a first embodiment.

FIG. 2 is also an explanatory diagram of a magnet and a position sensor.

FIG. 3 is a vertical sectional view of the piston.

FIG. 4 is an explanatory diagram of a magnet and a position sensor according to a second embodiment.

FIG. 5 is a front view of the third embodiment.

FIG. 6 is a side view of the same.

FIG. 7 is an explanatory diagram of a magnet and a position sensor of the same.

FIG. 8 is a side view of another example of the magnet.

FIG. 9 is a side view of still another example of the magnet.

FIG. 10 is an explanatory diagram of a magnet and a position sensor of a known position detecting device.

[Explanation of Codes] 10, 20 Fluid Pressure Cylinder 11 Piston 12, 23, 25, 30 Magnet 13, 21 Cylinder Tube 14, 16 Position Sensor 17 Magnetic Detecting Section 18, 26 Magnet Piece 22 Moving Element 31 Yoke

Claims (6)

[Scope of utility model registration request] 1. A moving part such as a piston or a mover that moves in synchronization with the piston, a fixed part such as a cylinder, a magnet attached to one of the moving part or the fixed part, and a magnet attached to the other. In a piston position detecting device for a fluid pressure cylinder equipped with a position sensor that detects a magnetic field of a magnet and outputs a signal, the direction of the magnetic pole of the magnet is substantially perpendicular to the moving direction of the moving part, and the position sensor The piston position detection device for a fluid pressure cylinder is characterized in that the direction of is substantially parallel to the direction of the magnetic force lines of the magnet. 2. The fluid according to claim 1, further comprising a ring-shaped magnet in which a plurality of radial magnetic poles are alternately magnetized in opposite directions and circumferentially magnetized. Pressure cylinder piston position detector. 3. The piston position detecting device for a fluid pressure cylinder according to claim 2, wherein the position sensor includes a plurality of magnetic detecting portions arranged in the direction of the magnetic lines of force of the magnets. 4. The piston position detecting device for a fluid pressure cylinder according to claim 1, further comprising a rod-shaped magnet having a magnetic pole in a width direction. 5. The fluid pressure according to claim 1, further comprising a magnet in which a plurality of magnet pieces having magnetic poles in mutually opposite directions are arranged side by side in a direction orthogonal to the direction of the magnetic poles. Cylinder piston position detector. 6. The piston position detecting device for a fluid pressure cylinder according to claim 5, wherein a yoke of a magnetic material is attached to the piston side of the magnetic pole.