JPH0421801B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that detects the position of a moving object, and particularly to a device that detects the position of a moving object, and in particular reduces the moving distance of the moving object by a certain ratio, and moves at a speed that is a fixed ratio of the moving object during this reduction stroke. This involves detecting a detection piece with a detector and knowing the actual position of the moving body.

Conventionally, screw-type indicators, rotary cam switches, and the like are known as this type of position detection device. In all of these conventional devices, a detection piece is moved in synchronization with the moving body from a moving body driving device via a decelerator during the actual length stroke of the moving body, and the detection piece is detected by a limit switch. When the actual length of the moving body is 200 m to 500 m, the deceleration rate of the decelerator is determined by changing the moving distance of the detection piece from 1 m to 2 m.
The length should be approximately m. Since the deceleration is extremely large as described above, if the detection piece moves with an error of several millimeters, the detected position of the moving object (for example, the stop command position) will have an error of about 1 m. The reason for this is that even when the moving body is at the detection position, the detection piece only moves slowly in accordance with the degree of deceleration, and the greater the degree of deceleration, the worse the detection accuracy becomes. In addition, if an attempt is made to increase accuracy by reducing the deceleration rate, the distance of the detection piece becomes longer, resulting in a disadvantage that the apparatus becomes larger.

An object of the present invention is to detect the position of a moving object with high accuracy.

An embodiment of the present invention will be described below with reference to FIGS. 1, 2, and 3.

A screw shaft 5 is connected to a drive device 1 for moving the movable body, and when the drive device 1 moves the movable body, the screw shaft 5 can rotate in synchronization. A nut 13 is screwed into the threaded groove of the screw shaft 5. The rotation direction of the nut 13 is restricted by the guide 4 so that it does not rotate, and can only move up and down. The screw shaft 5 has bearings 10 at the upper and lower parts of the guide 4.
11. Further, as shown in FIG. 3, an upper spring receiver 2 and a lower spring receiver 7 are integrally attached to the screw shaft 5 with a key 3, and are slidable only in the vertical direction. The lower spring receiver 7 is supported by a flange portion 14 that is integral with the screw shaft 5 so as not to fall below that level. A coil spring 8 is interposed between the upper and lower spring receivers 2 and 7, and supports the upper spring receiver 2 in a floating manner. That is, each of the upper and lower spring receivers 2 and 7 is an elastic receiver that contacts both ends of the coil spring 8 as an elastic member. If the upper spring 2 is the first elastic receiver, the lower spring receiver 7 is the second elastic receiver. A disk 6 is horizontally fixed to the upper spring receiver 2. A cam 9, which is a detection piece, is fixed to the upper surface of the disc 6 so as to protrude from the outer periphery. A limit switch 12 serving as a detector is supported by the guide 4 so that the contact terminal of the switch lever is horizontally opposed to the outer peripheral end surface of the disc 6.

In this embodiment, when the movable body is moved by the drive device 1, the screw shaft 5 connected to the drive device 1 also rotates. Therefore, the nut 13 moves in the vertical direction. The movement of the nut 13 is slowed down to a much greater extent than that of the moving body due to the pitch of the screw provided on the screw shaft 1 and the like. When the moving body moves toward the stop command position, the nut 13 gradually descends and approaches the spring receiver 2 side. During this time, the disc 6 continues to rotate because it is integral with the upper spring receiver 2 which is secured to the screw shaft 5 by the key 3, but the cam 9 rotates above the switch lever terminal of the limit switch 12 without contacting it. Then, when the moving body approaches the stop command device, the nut 13, which has continued to descend, finally pushes up the upper spring receiver 2 against the coil spring 8. The cam 9 on the pushed down disc 6 is the limit switch 12
It is at the same height as the switch lever terminal and still rotates. Moreover, this rotation is the same as the rotation speed of the screw shaft 5, and since the cam 9 is attached to the upper surface of the outer periphery of the disk 6, the rotational speed of the cam 9 is the same as the circumferential speed of the disk 6. It becomes high speed. Then, the cam 9, which moves at a much higher speed than the vertical speed of the nut 13, switches the limit switch 1.
2, the limit switch 12 informs the moving body that it is in a position where a stop command is given. In this way, in the detection work, the movement of the nut 13 is detected by the cam 9 at the detection point.
, and the cam 9 operates the limit switch 12. Therefore, even if the nut 13 moves slowly, the cam 9 moves quickly.
Detection accuracy is improved. In other words, as if Natsu 12
During the detection work, the deceleration applied to the
Detection errors do not lead to large actual measurement errors. When the nut 13 rises, the disk 6 and cam 9 are returned to their original positions by the force of the coil spring 8.

As described above, according to the present invention, the movement of the nut, which is set to be decelerated, is converted into the high-speed movement of the detection piece at the time of detection work, so that the detection accuracy can be improved even if the deceleration of the nut is set to a large value. The effect is that the detection accuracy is improved if the deceleration is the same as before without decreasing.

[Brief explanation of drawings]

FIG. 1 is an overall partially sectional view of a detection device according to an embodiment of the present invention, FIG. 2 is a plan view of the disk portion shown in FIG. 1, and FIG. 3 is the device shown in FIG. 1. FIG. 1...Movement drive device, 2...Upper spring holder,
3...Key, 4...Guide, 6...Disc, 7...
Lower spring receiver, 8...Coil spring, 9...Cam, 10, 11...Bearing, 12...Limit switch.

Claims (1)

[Claims] 1. A screw shaft interlockingly connected to a device for moving and driving a moving body, a nut screwed onto the screw shaft, a detent guide abutting the nut, and a screw attached to the end of the screw shaft. a first elastic bearing that is rotatable with the screw shaft; a second elastic bearing that is rotatable with the screw shaft and movable in the axial direction at a position where it can come into contact with the nut; and a first elastic bearing that is rotatable with the screw shaft and movable in the axial direction. and a second elastic receiver, an elastic member having elasticity in the axial direction, a detection piece provided protruding from the second elastic member in the radial direction of the screw shaft, and a detection piece capable of detecting the detection piece. A position detecting device for a moving body, comprising a detector placed at a certain position.