JPH08110202A - Piston position sensor - Google Patents

Abstract

PURPOSE: To apply this sensor to a plurality of cylinders different in lengths of the cylinders and piston strokes by preventing a magnetic sensor from shifting in an axial direction of the cylinder. CONSTITUTION: A piston position sensor includes a band member 6 engaged with a groove formed on an outer periphery of a cylinder 1 to be tightened with the cylinder 1 and a sensor support member 7 attached thereto. The sensor support member 7 is formed with a first attaching face 15 where a fixed magnetic sensor 17 is attached and a second attaching face 16 where a movable magnetic sensor 18 is attached. The movable sensor 18 is attached via an engaging member 22. The fixed sensor 17 is fixed to the first attaching faces 15 of one two sensor support members 7, while the movable sensor 18 is tightened to the second attaching face 16 of the other member 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pitsun position detecting device for detecting the position of a piston in a cylinder by a magnetic sensor which operates in response to a permanent magnet provided on the piston.

[0002]

2. Description of the Related Art When a piston, which is axially movable in a cylinder, is automatically operated by using air pressure or hydraulic pressure as a working fluid, it is detected by a sensor that the piston has reached a predetermined position. It is necessary to detect.
For example, the sensor automatically detects that the piston has reached the forward limit position and the backward limit position, and sends a detection signal from the sensor to the control device to control the next step. ing.

An example of a piston position detecting device used for detecting the piston position is, for example, an actual flat opening 6
There is one such as shown in Japanese Patent Publication No. -24208.

In the piston position detecting device disclosed in this publication, a rail having a length corresponding to the cylinder is fastened to the cylinder by a band member, and two magnetic sensors are attached to a groove formed in the rail. I have to.

[0005]

Thus, when two sensors, a sensor for detecting the backward limit position of the piston and a sensor for detecting the forward limit position of the piston are mounted on one rail, the cylinder is It is necessary to prepare a large number of rails having mutually different lengths corresponding to the length of the piston, that is, the stroke of the piston.

Further, the conventional piston position detecting device has a problem that the band member may be displaced in the axial direction of the cylinder due to vibration during the process of using the cylinder.

On the other hand, in the magnetic sensor for detecting the backward limit position of the piston, since the position of the backward limit of the piston is always unchanged, the position of the magnetic sensor is hardly adjusted along the rail. Therefore, unlike the above-described conventional piston position detecting device, it is not necessary to dispose the position of the magnetic sensor for detecting the backward limit position of the piston so as to be movable along the rail.

An object of the present invention is to provide a piston position detecting device in which the magnetic sensor is prevented from shifting in the axial direction of the cylinder.

Another object of the present invention is to provide a piston position detecting device which can be applied to a plurality of cylinders having different cylinder lengths and piston strokes.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0011]

Of the inventions disclosed in the present application, a representative one will be briefly described below.
It is as follows.

That is, the piston position detecting device of the present invention has a band member that is engaged with a groove formed on the outer periphery of the cylinder and fastened to the cylinder, and a sensor support piece member that is attached to the band member. . The sensor support piece member,
A first mounting surface on which a stationary magnetic sensor operated by a permanent magnet provided on the piston can be mounted and a second mounting surface on which a moving magnetic sensor operated by a permanent magnet can be mounted are formed. Further, the sensor support piece member has a second
An engaging groove is formed extending in the axial direction along the mounting surface, and an engaging member fixed to the moving side magnetic sensor engages with the engaging groove, and moves to the fixed side magnetic sensor on the sensor support piece member. It is characterized in that any one of the side magnetic sensors is attached.

Then, two sensor support piece members are attached to the cylinder by band members respectively, and the fixed side magnetic sensor is fixed to the first attachment surface of one of the two sensor support piece members, and the other sensor is attached. The moving side magnetic sensor is fastened to the second mounting surface of the support piece member.

[0014]

In the piston position detecting device described above, since the band member is engaged with the groove formed in the cylinder and the band member is fastened, the vibration due to the movement of the piston is propagated to the magnetic sensor. However, this avoids axial displacement of the magnetic sensor. The position of the moving side magnetic sensor can be adjusted by adjusting and moving the position of the engaging member to an arbitrary position along the engaging groove. When two magnetic sensors, a fixed side magnetic sensor and a moving side magnetic sensor, are used to detect the forward limit position and the backward limit position of the piston, for various cylinders having mutually different lengths. It is possible to apply the piston position detecting device having the same structure, and it is possible to apply to the piston position detection of a large number of cylinders with a small number of parts.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a front view showing a pneumatic cylinder provided with a piston position detecting device of the present invention, and FIG. 2 is a cross sectional view of FIG.

As shown in the figure, a piston 2 is axially movably mounted inside a cylinder 1. A piston rod 3 is provided on the piston 2, and the piston rod 3 projects outside the cylinder 1. ing. Piston 2
An annular groove is formed in the outer peripheral portion of the, and a permanent magnet 4 is provided in the groove as shown in FIG.

As shown in FIG. 1, the cylinder 1 detects a piston position detecting portion 5a for detecting that the piston 2 has moved to the forward limit position, and detects that the piston 2 has moved to the backward limit position. Piston position detector 5 for
Two detectors b and b are provided.

Each of the detecting portions 5a and 5b has a band member 6 and a sensor support piece member 7 screwed to the band member 6, and the front end portion of the cylinder 1 is made to correspond to each of the detecting portions 5a and 5b. The band member 6 is provided on the outer periphery of the rear end portion and
A groove 8 for engaging with is formed as shown in FIG. The free end of the band member 6 is fastened by the fastening member 9.

A convex portion 12 is formed by bending the band member 6, a concave groove 13 is formed in the sensor support piece member 7 attached to the band member 6, and the convex portion 12 is inserted into the concave groove 13. ing. With the convex portion 12 inserted in the concave groove 13, the band member 6 is fixed by the screw member 14.
The sensor support piece member 7 is attached to the. Band member 6
As shown in FIGS. 1 and 3, the sensor support piece member 7 is attached to one end side of the sensor support piece member 7 in the longitudinal direction.

As shown in FIG. 3, the sensor support piece members 7 are first phase-shifted from each other in the circumferential direction of the cylinder 1.
A mounting surface 15 and a second mounting surface 16 are formed, and a fixed-side magnetic sensor 17 that operates in response to the permanent magnet 4 can be mounted on the first mounting surface 15. Further, a moving side magnetic sensor 18 that operates in response to the permanent magnet 4 can be attached to the second attachment surface 16.

Therefore, both the solid-side magnetic sensor 17 and the moving-side magnetic sensor 18 can be attached to one sensor support piece member 7, and only one of them is fixed to the cylinder 1. It The magnetic sensors 17 and 18 are electrically connected to a control unit (not shown) via cables 17a and 18a.

As shown in FIG. 2, when the mounting surfaces 15 and 16 are extended, the two mounting surfaces 15 and 16 are inclined to each other so as to include the central axis of the piston 2.
Fixed-side magnetic sensor 17 attached to the first attachment surface 15
The sensor element, which is not shown, which is sensitive to magnetism is incorporated inside, and is attached by a screw member 19.

As shown in FIG. 3, the sensor support piece member 7 is provided with a T-shaped engaging groove 21, and the engaging member 22 is engaged in the engaging groove 21. It has become. A connecting member 24 having an L-shaped cross section is screwed to the engaging member 22 by a screw member 23.
The connecting member 24 is attached to the moving side magnetic sensor 1 by the screw member 25.
It is adapted to be screw-connected to 8.

The moving-side magnetic sensor 18 incorporates therein a sensor element (not shown) that is sensitive to magnetism.
The same type as the stationary magnetic sensor 17 is used. As described above, the moving-side magnetic sensor 18 uses the engaging member 22 and the connector 24 that are slidable along the engaging groove 21 to move to the second position.
Since it is attached to the sensor support piece member 7 in a state of being in contact with the attachment surface 16, the moving side magnetic sensor 1
8 can be attached to the sensor support piece member 7 with its position adjusted in the axial direction.

As shown in FIG. 1, in order to assemble the cylinder 1 having the piston position detecting device, the piston position detecting portion 5a is located at the front end side of the cylinder 1 and the piston position detecting portion 5b is located at the rear end portion of the cylinder 1. On the side, each band member 6 is engaged with the groove 8 formed in the outer periphery of the cylinder 1 and fastened to the cylinder 1. A sensor support piece member 7 is attached to each band member 6 in advance by a screw member 14.

As shown in FIG. 1, the piston position detector 5
The second mounting surface 16 of a and the first mounting surface 15 of the piston position detector 5b are on the same side, and the two magnetic sensors 1
7 and 18 face the same side, and the respective band members 6 are located on the end side of the cylinder 1.

The first mounting surface 15 of the sensor support piece member 7 of the piston position detector 5b fastened to the rear end of the cylinder 1.
The fixed-side magnetic sensor 17 is attached to the plate by the screw member 19, and the second attachment surface 16 is left as it is. The band member 6 may be fastened with the fixed-side magnetic sensor 17 attached to the first attachment surface 15 in advance.

The screw member 2 is attached to the sensor supporting piece member 7 of the piston position detecting portion 5a fastened to the tip end of the cylinder 1.
3, 25, the coupling tool 24, and the engaging member 22 are attached with the moving-side magnetic sensor 18 in contact with the second mounting surface 16 with the moving-side magnetic sensor 18 attached. When mounting, the screw member 23 is loosened, and the position of the moving side magnetic sensor 18 is set while moving the engaging member 22 in the engaging groove 21. The position to be set is, for example, a position where the piston 2 becomes the forward limit position, and various positions such as the front side of the forward limit position are set depending on the usage mode of the cylinder 1.

In the case shown in FIG. 2, the two sensor support piece members 7 are attached to each other in the same phase in the circumferential direction of the cylinder 1, but the sensor support piece members of the piston position detecting portion 5a are mounted. 7 so that the second mounting surface 16 of the piston 7 and the first mounting surface 15 of the sensor supporting piece member 7 of the piston position detecting portion 5b are located in the same plane, the phases of the two supporting piece members 7 are shifted from each other. Is also good.

If only one of the forward limit position and the backward limit position of the piston 2 is to be detected, only one piston position detection portion is attached to the cylinder 1.

As described above, in order to detect the position of the piston 2 moving in the cylinder 1, both the fixed side magnetic sensor 17 and the moving side magnetic sensor 18 can be attached to the sensor support piece member 7. The two piston position detectors 5a and 5b are provided with either one of the fixed magnetic sensor 17 and the movable magnetic sensor 18 which are separate from each other for the forward limit position and the backward limit position of the piston 2, respectively. Is used. Therefore, the same type of piston position detecting device can be applied to various cylinders 1 having different lengths, that is, different piston strokes.

Further, since the band member 6 is engaged with the groove 8, even if vibration is generated by the reciprocating movement of the pitsun 2,
The piston position detector will not shift.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, although the illustrated cylinder 1 is an air cylinder operated by air pressure, the present invention can be applied to a cylinder operated by hydraulic pressure.

[0036]

Advantageous effects obtained by typical ones of the inventions disclosed in the present application will be briefly described.
It is as follows.

(1). Since the band member is engaged with the groove formed in the cylinder, the magnetic sensor is prevented from shifting in the axial direction of the cylinder.

(2) Both the fixed side magnetic sensor and the moving side magnetic sensor can be attached to the sensor support piece member, and two sensor support piece members, one of which is attached respectively, are attached to the cylinder. The same type of piston position detecting device can be used for various cylinders having mutually different lengths.

(3) As a result, the number of parts can be reduced.

[Brief description of drawings]

FIG. 1 is a front view showing a cylinder equipped with a piston position detecting device according to an embodiment of the present invention.

2 is a cross-sectional view of FIG.

FIG. 3 is an exploded perspective view showing a piston position detection unit shown in FIG.

4 is a sectional view taken along line IV-IV in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 cylinder 2 piston 3 piston rod 4 permanent magnets 5a, 5b piston position detection part 6 band member 7 sensor support piece member 8 groove 9 fastening member 12 convex part 13 concave groove 14 screw member 15 first mounting surface 16 second mounting surface 17 Fixed side magnetic sensor 18 Moving side magnetic sensor 19 Screw member 21 Engaging groove 22 Engaging member 23 Screw member 24 Connecting tool 25 Screw member

Claims (2)

[Claims] 1. A piston position detection device for detecting the position of a piston movably mounted in a cylinder, the band member engaging with a groove formed on the outer periphery of the cylinder and fastened to the cylinder. A first mounting surface to which a fixed magnetic sensor that operates by a permanent magnet provided on the piston can be mounted; and a permanent magnet formed at a position displaced in the circumferential direction of the cylinder with respect to the first mounting surface. A sensor support piece member fixed to the band member and having a second attachment surface to which a moving side magnetic sensor operated by a magnet can be attached; and an axial direction of the sensor support piece member along the second attachment surface. An engaging member that is axially adjustable and movable in an extending engagement groove, and is fixed to the moving-side magnetic sensor; Piston position detecting apparatus being characterized in that to attach one of the movable magnetic sensor. 2. The piston position detection device according to claim 1, wherein two sensor support piece members are attached to the cylinder by the band member, respectively, and one of the two sensor support piece members is attached to the sensor support piece member. The fixed-side magnetic sensor is fixed to the first mounting surface, and the moving-side magnetic sensor is brought into contact with the second mounting surface of the other sensor support piece member to be fastened by the engaging member. Characteristic piston position detection device.