JPH10274U - Operating position detector for rodless cylinder - Google Patents

Abstract

(57) [Problem] To provide a piston operating position detecting device that does not cause a malfunction in a rodless cylinder. SOLUTION: The rodless cylinder includes a moving member 12 which moves in synchronization with a piston, and a fixed portion having a cylinder tube 11. In order to detect the operating position of the moving element 12 in this rodless cylinder, a rod-shaped magnet 13 is attached to the hanging portion 12a of the moving element 12, and the magnetic field of the magnet 13 is detected at a position facing the magnet 13 on the outer surface of the fixed portion. And a position sensor 15 for outputting a signal. The magnet 13 sets the direction of the magnetic pole to a direction substantially orthogonal to the moving direction of the moving element 12, and the position sensor 15 sets the direction of the sensitivity to be substantially parallel to the direction of the magnetic force lines emitted from the magnet 13.

Description

[Detailed description of the invention]

[0001]

[Industrial applications]

 The present invention relates to an operating position detecting device in a fluid pressure driven rodless cylinder.

[0002]

[Prior art]

 As shown in Fig. 6, a piston 2 of a hydraulic cylinder is provided with a magnet 2 and a position sensor 3 for detecting a magnetic field of the magnet 2 and outputting a signal is attached to the cylinder. , Already known. As shown in FIG. 6, the magnetic poles of the magnet 2 in the above-described known position detecting device are arranged such that the lines of magnetic force emerge in a direction parallel to the moving direction of the piston 1. On the other hand, since the position sensor 3 has directivity in sensitivity, it is necessary to mount the position sensor in the direction of the line of magnetic force in the magnet 2, that is, in the direction parallel to the moving direction of the piston.

The above-described known piston position detecting device has a simple structure of the magnet 2, but may malfunction if the magnetic force of the magnet 2 is too strong or the distance between the magnet 2 and the position sensor 3 is too short. There is. As shown in FIG. 6, this malfunction is caused by the presence of magnetic field lines B and B that cause malfunctions, in addition to the magnetic field lines A to be detected by the position sensor 3, as magnetic field lines in the piston movement direction of the magnet 2. is there. For this reason, it is necessary to make the magnet 2 generate an appropriate line of magnetic force with respect to the position sensor 3, so that there is a problem that the material, size, shape, and the like of the magnet are limited.

On the other hand, a rodless cylinder includes a mechanical joint type in which a piston and a moving element are mechanically connected to each other through a slit provided in a cylinder tube, and a magnet cup in which a magnet that attracts the piston and the moving element to each other is provided. Although there are ring-type cylinders, in any of these rodless cylinders, in order to provide a position detecting device that detects the piston position, the following problems different from cylinders equipped with piston rods are required. is there.

[0005] That is, in the former mechanical joint type rodless cylinder, when a magnet is provided on the piston and a piston position detecting switch is fitted into a fitting groove provided in the cylinder, the cylinder tube is thinned by the fitting groove. As a result, the cylinder tube having the slit may be deformed by the fluid pressure for driving the piston, and the interval between the slits may be widened, and it is necessary to increase the strength of the cylinder tube so as to suppress the gap. Will increase.

Further, in a magnet-coupling type rodless cylinder having a piston and a movable element provided with magnets that attract each other, in order to detect the position of the piston, the position of the piston is not affected by the magnetic field of the magnet constituting the magnet coupling. It is necessary to install a position detector at the position, and consider the structure to prevent the influence of the magnetic field, or set the position of the position detector to an arbitrary position that is less affected by the magnetic field It becomes necessary. In any case, providing a position detecting device for detecting the piston position in a rodless cylinder involves a different problem from a normal cylinder having a piston rod.

[0007]

[Problems to be solved by the invention]

 The basic technical problem of the present invention is that there is no possibility of the above-mentioned malfunction described above with reference to FIG. 6 and that the operating position detecting device which has solved various problems when the piston position detecting device is provided in the rodless cylinder. Is to provide. A more specific technical problem of the present invention is to provide a rodless cylinder operating position detecting device which eliminates the need to provide a switch mounting groove for reducing the strength of the cylinder tube. Another technical problem of the present invention is that even in a magnet coupling type rodless cylinder in which a piston and a moving element are provided with magnets adsorbing to each other, the magnet can be installed without being affected by the magnet constituting the magnetic coupling. It is to provide a position detector.

[0008]

[Means for Solving the Problems]

 In order to solve the above-mentioned problem, the present invention provides a position detecting device for detecting an operating position of the movable element in a rodless cylinder including a movable element that moves in synchronization with a piston and a fixed portion having a cylinder tube. A magnet attached to the mover, and a position sensor attached at a position facing the magnet on the outer surface of the fixed part so as to be position-adjustable and detecting a magnetic field of the magnet and outputting a signal, The direction of the magnetic pole of the magnet is substantially perpendicular to the direction of movement of the moving element, and the direction of the sensitivity of the position sensor is substantially parallel to the direction of the magnetic force lines emitted from the magnet. . In the operating position detecting device, a magnet is attached to a hanging part of the moving element that moves on the fixed part, which hangs down on an outer surface of the fixed part, and a position sensor is attached to a position facing the magnet on the outer surface of the fixed part. Can be.

The magnet in the operating position detecting device is a rod-shaped magnet extending in the moving direction of the moving element, or a plurality of magnet pieces having different magnetic poles on an end face are formed in a direction orthogonal to the direction of the magnetic pole. In this case, a magnetic yoke can be provided on the side opposite to the magnet piece position sensor.

In the rodless cylinder operating position detecting device having the above-described configuration, when the moving element that moves in synchronization with the piston moves relative to the fixed portion including the cylinder tube, the magnet provided on the moving element is used. When the sensor approaches the position sensor attached to the fixed portion, the position sensor detects the magnetic field of the magnet and outputs a signal, so that the position of the moving element can be detected. In this case, the direction of the magnetic pole of the magnet was set to a direction substantially orthogonal to the moving direction of the moving element, and the direction of the sensitivity of the position sensor was set to be substantially parallel to the direction of the magnetic force lines emitted from the magnet. Magnetic lines of force that cause the sensor to malfunction as described with reference to FIG. 6 do not act on the sensor, so that malfunction of the position detecting device can be reliably prevented. Further, by making the magnet into a rod shape having an appropriate length, the operating range of the position sensor can be lengthened, or the sensitivity, detection accuracy, and the like can be adjusted in relation to the moving speed of the moving element.

Further, in a mechanical joint type rodless cylinder in which a piston and a moving element are mechanically connected through a slit provided in a cylinder tube, it is necessary to provide a switch mounting groove in the cylinder tube to reduce the strength. In particular, by mounting a magnet on the hanging part of the slider that hangs on the outer surface of the fixed part, and mounting a position sensor on the outer surface of the fixed part at a position facing the magnet, the strength of the cylinder tube can be reduced. It becomes possible to suppress.

On the other hand, in a magnet-coupling-type rodless cylinder provided with magnets that are attracted to the piston and the moving element, even if there is a leakage magnetic flux from the magnets that constitute the magnet coupling to the outside, the magnets can be used. The magnetic flux coming out of the magnetic pole is also directed in the radiation direction but mainly in the direction of movement of the piston, whereas the magnet attached to the mover changes the direction of the magnetic flux emerging from its magnetic pole in the direction of movement of the mover. Direction, and the direction of the sensitivity of the position sensor is almost parallel to the direction of the line of magnetic force emerging from the magnet (perpendicular to the direction of movement of the mover). There is almost no influence and the position of the moving element can be detected reliably.

[0013]

【Example】

 FIGS. 1 to 3 show an embodiment of a rodless cylinder driven by fluid pressure according to the present invention. The rodless cylinder 10 has a fixed portion provided with a cylinder tube 11, and a fluid inside the cylinder tube 11. A piston (not shown) driven by pressure; and a moving element 12 that moves in synchronization with the piston along a cylinder tube 11, and further detects an operating position of the moving element 12 in the rodless cylinder 10. And a position detecting device to be described below.

That is, the movable member 12 that moves on the fixed portion (cylinder tube 11) is provided with a hanging portion 12a that depends on the outer surface of the fixed portion, and a rod-shaped magnet 13 is attached to the hanging portion 12a. At a position facing the magnet 13 on the outer surface of the fixed portion, a sensor mounting portion 14 having a position sensor 15 is mounted so as to be movable in the longitudinal direction of the cylinder tube 11. . As shown in FIG. 3, the rod-shaped magnet 13 has a magnetic pole that emits magnetic lines of force in the width direction of the cylinder tube 11. The direction of the sensitivity of the position sensor 15 is substantially parallel to the direction of the magnetic line of magnet 13. It is installed in such a way. Therefore, the flow of the lines of magnetic force from the magnet 13 is in a direction substantially orthogonal to the moving direction of the moving element 12 and the magnet 13.

In the rodless cylinder of the first embodiment having the above configuration, when the magnet 13 provided on the moving element 12 approaches the position sensor 15 attached to the fixed part, the position sensor 15 detects the magnetic field of the magnet 13. Thus, the position of the moving element 12 can be detected. In this case, the direction of the magnetic pole of the magnet 13 is set to a direction substantially perpendicular to the moving direction of the moving element 12, and the direction of the sensitivity of the position sensor 15 is set substantially parallel to the direction of the magnetic force line from the magnet 13. Therefore, the lines of magnetic force which cause the sensor to malfunction as described with reference to FIG. 6 do not act on the position sensor 15, and it is possible to reliably prevent the malfunction of the position detecting device. I do not receive it. Further, by making the magnet 13 in a rod shape having an appropriate length, the operating range of the position sensor 15 can be lengthened, or the sensitivity, detection accuracy, and the like can be adjusted in relation to the moving speed of the moving element. it can.

When the rodless cylinder 10 is a mechanical joint type rodless cylinder in which a piston and a moving element are mechanically connected to each other through a slit provided in a cylinder tube, a drooping drooping on an outer surface of a fixed portion of the moving element 12. By mounting the magnet 13 on the portion 12a and mounting the position sensor 15 at a position facing the magnet 13 on the outer surface of the fixed portion, it is possible to prevent a switch mounting groove from being provided in the cylinder tube to reduce the strength thereof. It is possible to suppress a decrease in the strength of the cylinder tube. Even if a groove for mounting the sensor mounting portion 14 is provided in the cylinder tube 11, it can be made sufficiently shallower than the mounting groove for mounting the position sensor itself.

On the other hand, when the rodless cylinder 10 is a magnet-coupling type rodless cylinder provided with magnets that adsorb to each other on a piston and a moving element, the rodless cylinder 10 has an external force from a magnet constituting the magnet coupling. Even if there is magnetic flux leaking to the magnet, the magnetic flux emitted from the magnetic pole of the magnet is also directed in the radiation direction but mainly in the direction of movement of the piston. In the magnet 13, the direction of the magnetic flux emitted from its magnetic pole is set to a direction substantially orthogonal to the moving direction of the moving element 12, and the direction of the sensitivity of the position sensor 15 is substantially parallel to the direction of the magnetic force lines emitted from the magnet 13 (moving element). 12), the position sensor 15 is hardly affected by the magnets constituting the magnet coupling, and the position of the movable Position detection can be performed.

FIG. 4 shows another example of the structure of the magnet provided on the mover 12. The magnet 25 is composed of two magnet pieces 26, 26 having different magnetic poles on their end faces, which are substantially orthogonal to the direction of the magnetic poles. Are arranged side by side in the same direction. FIG. 5 shows still another example of the structure of the magnet. The magnet 30 prevents the magnetic field lines formed of a magnetic material such as iron from leaking to the magnetic pole opposite to the position sensor of the magnet 25 shown in FIG. The yoke 31 is attached.

The manner in which the magnets 25 and 30 are attached to the movable element 12 and the operation thereof are substantially the same as those of the magnet 13, and a detailed description thereof will be omitted.

[0020]

[Effect of the invention]

 According to the present invention, the direction of the magnetic pole of the magnet attached to the moving element that moves in synchronization with the piston of the fluid pressure cylinder is set to a direction substantially orthogonal to the moving direction of the moving element, and the sensitivity of the position sensor is reduced. Since the orientation is set substantially parallel to the direction of the magnetic field lines of the magnet, malfunction of the position detection device can be reliably prevented. Therefore, an arbitrary magnetic force or a magnet having a size and the like can be used. Either a mechanical joint type rodless cylinder in which a piston and a moving element are mechanically connected to each other through a slit provided in a cylinder tube, or a magnet coupling type rodless cylinder in which a magnet that attracts the piston and the moving element to each other is provided. Also, the problem in the case of providing a position detecting device for detecting the operating position of the piston can be solved.

[Brief description of the drawings]

FIG. 1 is a front view of a first embodiment.

FIG. 2 is a side view of the same.

FIG. 3 is an explanatory diagram showing a relationship between a magnet and a position sensor in the embodiment.

FIG. 4 is a front view showing another example of the structure of the magnet.

FIG. 5 is a front view showing still another example of the structure of the magnet.

FIG. 6 is an explanatory diagram of a magnet and a position sensor of a known position detection device.

[Explanation of symbols]

 Reference Signs List 10 fluid pressure cylinder 12 mover 13, 25, 30 magnet 11 cylinder tube 15 position sensor 26 magnet piece 31 yoke

Claims (5)

[Utility model registration claims] 1. A position detecting device for detecting an operating position of a mover in a rodless cylinder including a mover that moves in synchronization with a piston and a fixed portion having a cylinder tube, the mover comprising: And a position sensor that is mounted at a position opposing the magnet on the outer surface of the fixed portion and that detects the magnetic field of the magnet and outputs a signal. An operating position detecting device for a rodless cylinder, characterized in that the direction of the sensitivity of the position sensor is substantially parallel to the direction of the line of magnetic force emitted from the magnet, the direction being substantially perpendicular to the moving direction of the moving element. 2. A magnet which is attached to a hanging part of the movable member which moves on the fixed part and which hangs down from an outer surface of the fixed part, and a position sensor is attached to a position facing the magnet on the outer surface of the fixed part. The operating position detecting device for a rodless cylinder according to claim 1. 3. The rodless cylinder operating position detecting device according to claim 1, wherein the magnet is a rod-shaped magnet extending in the moving direction of the moving element. 4. A plurality of magnet pieces having different magnetic poles on an end face,
The operating position detecting device for a rodless cylinder according to claim 1 or 2, wherein the magnets are arranged side by side in a direction perpendicular to the direction of the magnetic poles. 5. The rodless cylinder operating position detecting device according to claim 4, wherein a yoke made of a magnetic material is provided on the side opposite to the position sensor of the magnet piece.