JPH0640327Y2 - Cylinder device with stroke sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a cylinder device with a stroke sensor capable of detecting a cylinder stroke.

(Prior Art) Many cylinder devices including a stroke sensor for detecting a cylinder stroke amount of a fluid pressure cylinder, for example, a hydraulic cylinder have been filed, including Japanese Patent Application No. 61-100250.

The stroke sensor is attached to the cylinder head of the cylinder, and a magnetic sensor or the like that detects the stroke amount of the piston rod is often used. For this reason, a magnetic scale is embedded in the piston rod at a predetermined pitch interval. With the movement of the piston rod, the magnetic sensor generates an output wave of a sine curve synchronized with the scale pitch.

(Problems to be solved by the invention) By the way, the magnetic scale embedded in the piston rod is formed not on the entire circumference of the piston rod but on one side so as not to impair the mechanical strength of the piston rod. Therefore, the position where the magnetic sensor is mounted is limited to the position facing this scale.

The positional relationship of the piston rod with respect to the cylinder tube in the circumferential direction is regulated by the direction of the clevis at the mounting parts on both ends, so if the position of the magnetic sensor with respect to the cylinder tube is determined, the position of the piston rod with respect to the magnetic scale Relationships can be matched correctly.

However, when the cylinder head is attached to the cylinder tube, the cylinder head is usually screwed into the cylinder tube.Therefore, when the cylinder head is fastened with the specified tightening torque, the cylinder head moves in the circumferential direction with respect to the cylinder tube. There is no guarantee that the positional relationship will always be constant.

For this reason, if the magnetic sensor is integrally attached to the cylinder head beforehand, the magnetic sensor and the magnetic scale of the piston rod may not face each other correctly when fastened to the cylinder tube. Can no longer be detected.

It is also possible to fix the cylinder head with multiple bolts at a predetermined position without screwing it into the cylinder tube.In this case, a screw is formed on the fitting surface between the cylinder head and the cylinder tube. It is not applicable to the type that has the above-mentioned type, is inferior in versatility, and causes an increase in product cost.

The present invention aims to solve such a problem.

(Means for Solving the Problems) Therefore, the present invention is to mount a cylinder head through which a piston rod slides freely in a cylinder tube, and dispose a sensor holder having a built-in sensor on the end surface of the cylinder head. The positioning member attached to the holder was engaged with the working fluid pipe provided on the cylinder tube so as to project to the outside of the cylinder tube.

(Function) The cylinder head is screwed to the cylinder tube with a predetermined tightening torque, and then the sensor holder is brought into close contact with the end surface of the cylinder head to determine the piston rod axial position of the magnetic sensor. Further, by engaging the positioning member of the sensor holder with the working fluid pipe projectingly provided on the outer circumference of the cylinder tube, the circumferential position of the sensor is correctly set.

(Embodiment) FIGS. 1 to 3 show an embodiment of the present invention.

In the figure, 1 is a cylinder tube, 2 is a cylinder head screwed into this cylinder tube 1, 3 is a piston rod, 4
Is a stroke sensor unit.

The cylinder head 2 is screwed into the cylinder tube 1 via a threaded portion 5 formed on the fitting surface, and the piston rod 3 is slidably penetrated through the inner circumference thereof.

A working fluid pipe 6 is fixed to the cylinder tube 1 in a state of communicating with an internal oil chamber.

An annular step portion 8 concentric with the piston rod 3 is formed on the end surface of the cylinder head 2, and an annular recess 10 provided in the sensor holder 9 of the stroke sensor portion 4 with respect to the annular step portion 8.
Fit together. The sensor holder 9 having the through hole 11 of the piston rod 3 in the center is provided with a plurality of set screws 12 in the radial direction, and the set screws 12 are inserted and fastened in the annular groove 13 formed in the annular stepped portion 8. , The sensor holder 9 is closely fixed to the end surface of the cylinder head 2. In order to perform circumferential positioning when fixing the sensor holder 9, a positioning plate (positioning member) 7 is attached to the end of the sensor holder 9 via a screw 15, and the tip of the positioning plate 7 is branched. The part 16 is inserted into the pipe 6.

A magnetic sensor 14 is built in the sensor holder 9, and the sensor 14 detects a magnetic scale (not shown) formed on one side surface of the piston rod 3.

With the above configuration, therefore, in order to mount the stroke sensor unit 4 in a state where the cylinder head 2 and the sensor holder 9 are previously inserted into the piston rod 3,
First, the cylinder head 2 is fastened to the cylinder tube 1 via the threaded portion 5 with a predetermined tightening torque, and then the annular step portion 8 and the annular step portion 8 are arranged so that the end surface of the sensor holder 9 comes into close contact with the end surface of the cylinder head 2. The recess 10 is fitted. In this state, the axial position of the piston rod 3 of the magnetic sensor 14 is determined.

At this time, the sensor holder 9 is previously attached to the branch portion 16 of the positioning plate 7.
Is rotated until it coincides with the pipe 6, and the sensor holder 9 is fixed to the cylinder head 2 by the set screw 12. The position of the positioning plate 7 is pre-positioned so that the magnetic sensor 14 housed in the sensor holder 9 faces the magnetic scale of the piston rod 3, so that the circumferential position of the magnetic sensor 14 is set correctly in this state. It

The piston rod 3 is rotatable with respect to the cylinder tube 1 (cylinder head 2), but in the mounted state during use, the positional relationship between the end of the piston rod 3 (clevis) in the mounting hole (clevis) and the cylinder tube 1 is changed. Since it is set in advance, if the magnetic sensor 14 is set at the correct position in the circumferential direction of the cylinder tube 1, it will correspond exactly to the magnetic scale of the piston rod 3.

As described above, according to the present invention, the magnetic sensor can be mounted at the correct position with respect to the magnetic scale of the piston rod by combining the cylinder tube piping and the positioning member provided on the sensor holder. The cylinder stroke can always be detected accurately. The cylinder head can use a normal screw-in type, does not require any significant changes to the conventional structure, and uses the existing piping of the cylinder tube for positioning, which simplifies the positioning mechanism. There is also the effect.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention, FIG. 2 is a front view of the same, and FIG. 3 is a plan view of a positioning plate. 1 ... Cylinder tube, 2 ... Cylinder head, 3 ... Piston rod, 4 ... Stroke sensor section, 6 ... Piping, 7 ...
Positioning plate, 8 ... Annular step, 9 ... Sensor holder, 10 ... Annular recess, 12 ... Set screw, 13 ... Annular groove, 14 ... Magnetic sensor.

Claims (1)

[Scope of utility model registration request] 1. A cylinder head having a piston rod slidably penetrating the cylinder tube, a sensor holder having a built-in sensor is arranged on the end surface of the cylinder head, and a positioning member attached to the sensor holder is used as a cylinder tube. A cylinder device with a stroke sensor engaged with a working fluid pipe provided on the cylinder tube so as to project to the outside of the cylinder.