JP2003301808A - Load positioning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a load positioning device capable of eliminating a stop position error and achieving compactness. <P>SOLUTION: This load positioning device is provided with a body 16, a table 18 movable along the outer surface of the body, a pair of guides 48 to guide the movement of the table, a feed screw 12 rotatably supported in the body, an electric motor 13 installed on the shaft end of the feed screw, a movable member movable in the body as the feed screw is rotated, a connection body 20 for connecting the movable member to the table through a slit 19 formed in the body, a number of balls 29 rolling between screw grooves in the movable member and the feed screw, and a dust seal 49 to cover the slit. By the rotation of the feed screw by the electric motor, the table is moved, so that a load is stopped at a target stop position. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load positioning device for accurately positioning a stop position of a load. 2. Description of the Related Art A rotatable feed screw, a table provided with screw grooves of the same pitch as the screw grooves of the feed screw on the inner peripheral surface, and a large number of rollers which are rotatably inserted between these screw grooves. Ball, and an electric motor for rotating the feed screw, the table is moved by the rotation of the feed screw by the electric motor,
A load positioning device for stopping a load of a work or the like attached to a table at a target stop position is already known. Since the positioning device positions the load by rotation of the electric motor, the stop position is accurate when the weight of the load is small. [0003] It is an object of the present invention to improve the above positioning device and to provide a load positioning device which is free from errors in the stop position and can be downsized. In order to solve the above problems, a load positioning device according to the present invention includes a body, a table movable along the outer surface of the body in a longitudinal direction of the body, and a body. A guide that guides the movement of the table, a feed screw that is provided in the body in the longitudinal direction thereof, and is rotatably supported by the body,
An electric motor in which a rotor is attached to a shaft end of the feed screw so as to rotate integrally, a moving member through which the feed screw penetrates, and a moving member that moves in the body by rotation of the feed screw, and a slit formed in the body. A coupling body for coupling the moving member and the table, and a belt-shaped dust seal that is inserted through the table and located outside the slit and covers the slit, the electric motor rotates the feed screw to move the table. Thus, the load can be stopped at the target stop position. FIG. 1 to FIG. 5 show an embodiment of the present invention. This load positioning device 10 comprises a well-known rodless cylinder 11 having mechanical coupling means, 11, a feed screw 12 penetrating a piston, and an electric motor 1 for rotating the feed screw 12
3, and a pressure control valve 14 and a switching valve 15 (see FIG. 5) for supplying and discharging compressed air at a desired pressure to a cylinder chamber described later of the rodless cylinder 11. The rodless cylinder 11 shown in detail in FIGS. 1 and 2 has a body 16, a piston 17 moving in a cylinder 16 a provided on the body 16, and a body 16.
And a moving member formed by a piston 17 and the table 18 are connected to each other through a slit 19 formed in the body 16.
By 0, they are integrally movably connected. The body 16 is provided with a pair of guides 48 for guiding the movement of the table 18. The guide 48 can be constituted by a linear motion bearing, a slide guide, a cam follower, a needle bearing, or the like. The piston 17 has a piston yoke 17a smaller in diameter than the cylinder 16a, and piston bodies 17b, 17b connected to both axial sides of the piston yoke to move in the cylinder 16a in an airtight manner. The slits 19 of the cylinder chambers 21 and 21 are compressed by the compressed air pressure supplied to the cylinder chambers 21 and 21.
a seal belt 2 pressed against the slit 19 from inside
2 sealed. The outside of the slit 19 is covered with a belt-shaped dust seal 49 inserted through the table 18. Both ends of the cylinder 16a are connected to the body 16
The feed screw 12, which is closed by end plates 24a, 24b (FIGS. 1 and 4) attached to the end plate and penetrates a moving member formed by the piston 17, is supported by bearings 25, 25 provided on the end plates 24a, 24b. Rotatably supported,
A plurality of (two in the illustrated example) thread grooves 26 are formed on the outer peripheral surface of the feed screw 12 excluding both end portions. The screw grooves 26 have a length substantially equal to a length for moving a load (not shown) attached to the table 18 and are formed by rolling or grinding. A small arc surface may be provided at the opening edge of the groove. Further, the outer circumferential surface of the thread groove formed at a desired depth can be cut or ground to form a shallow thread groove. The piston bodies 17b, 17b have the same number of thread grooves 2 at the same pitch as the thread grooves 26,.
, And these screw grooves 27,.
(Refer to FIG. 3), and has a thread groove 26,... And a thread groove 27,.
A large number of balls 29, which are rollably inserted between
Are moved from one end of the thread groove 27 to the ball return hole 28 by the reciprocating motion of the piston 17 or the rotation of the feed screw 12.
, Through the ball return holes 28,.
7, and so on. However, the screw grooves 27, and the ball return holes 28,.
Is a piston yoke 17 instead of the piston body 17b.
a can also be provided. [0011] Seal assemblies 31, 31 are attached to the piston chambers 17b, 17b on the cylinder chamber 21, 21 side. The seal assembly 31 includes an assembly main body 32 and groove seal members 33 for sealing the screw grooves 26 of the feed screw 12 provided on the inner peripheral surface thereof (see FIG. 3). The groove sealing member 33 has a cross section for sealing the thread groove 26, and is usually made of an elastic material such as synthetic rubber or synthetic resin having a small friction coefficient.
At least once, preferably multiple times, more preferably 2
It is configured as a spiral body surrounding the screw groove 26 up to three times, but when the clearance with the screw groove 26 is reduced, it may be formed of metal. The number of turns of the thread groove of the groove sealing member 33 increases as the number of turns increases, but the more the number of turns increases, the more frictional resistance increases and the resistance of the piston 17 increases. Is most preferred. Further, a spring (not shown) is contracted between the piston bodies 17b, 17b and the piston yoke 17a, and the piston bodies 17b, 17b
By applying a preload to b, backlash due to the thread groove can be reduced. As shown in FIG. 4, the end of the feed screw 12 on the side of the electric motor 13 has reduced diameter portions 12a and 12b.
The rotor of the electric motor 13 is attached to the reduced diameter portion 12b so as to be integrally rotatable. The spacer 39 attached to the end plate 24a and the bearings 25, 25 are prevented from moving in the axial direction by a lock nut 37 screwed to the reduced diameter portion 12a, and the outer periphery of the annular spacer 39 is prevented. Oil seal 40
Is installed. Further, the end plate 24a and the electric motor 1
3 are formed in the adapter 44 which is provided between the adapter 3 and the cover 44 to cover the reduced diameter portion 12b. As schematically shown in FIG. 5, the end plates 24a, 2a
4b are formed with ports 46a and 46b for supplying and discharging compressed air to and from the cylinder chambers 21 and 21, respectively. Further, these ports 46a and 46b are connected to flow paths 47, 47 opened in the longitudinal direction of the body 16 (see FIG. 2).
, Which individually communicate with corresponding ports on the opposite end plate. Therefore, compressed air can be supplied to and discharged from the cylinder chambers 21 and 21 from either side of the end plates 24a and 24b.
The installation posture of the positioning device 10 is not restricted by the position of the port. When the positioning device 10 is installed in a substantially vertical direction to serve as a balancer that lifts a load, the upper port can be used as a breathing port. The pressure control valve 14 is a proportional solenoid 1
4a is configured as a proportional electromagnetic pressure control valve that outputs an air pressure proportional to the amount of electricity supplied to the solenoid valve 4a. The switching valve 15 is configured to excite the compressed air output from the pressure control valve 14 by exciting and releasing the solenoid 15a. It is configured as a well-known 5-port solenoid valve for supplying and discharging to and from 21 and 21. However, the pressure control valve 14 and the switching valve 15 are not limited to this, and the pressure control valve may be any as long as it can change the output fluid pressure, and the switching valve is operated between the ports by fluid pressure or mechanical operating means. The communication can be switched, and a four-port valve can be used. In the above embodiment, the electric motor 13 is usually installed in a substantially vertical direction with the electric motor 13 being upward or downward, but the installation posture is not limited to this, and the electric motor 13 can be installed in an inclined direction or a horizontal direction. When air at a predetermined pressure output from the pressure control valve 14 is supplied to one of the cylinder chambers 21 by the switching valve 15 and the air in the other cylinder chamber 21 is discharged to the outside, the piston 17 and the table 18 are driven by the supplied air pressure. After moving in a predetermined direction, the feed screw 12 is rotated by the balls 29,..., And the piston 17 and the table 18 are positioned at the terminal positions of the screw grooves 26,. Stops when moving close. After the piston 17 and the table 18 are stopped, the output air pressure of the pressure control valve 14 is reduced, and the acting force of the load acting on the piston 17 and the thrust of the piston 17 (the pressure receiving area of the piston × supply air pressure) are obtained. When the feed screw 12 is rotated by the electric motor 13 and the piston 17 and the table 18 are slightly moved in a direction opposite to the above moving direction, the load attached to the table 18 is accurately stopped at the target stop position. Can be. In this case, even if the weight of the load attached to the table 18 is large, the acting force due to the load is opposed to the thrust of the piston 17 which is substantially equal thereto, so that the electric motor 13 does not become overloaded. Even when the load is heavy, the vehicle can be accurately stopped at the target stop position. However, if the load is small, it can be driven only by the electric motor 13. FIG. 6 shows an example of the mode of use of the present invention, in which the rodless cylinder 1 constituting the load positioning device 10 is shown.
1 is installed substantially horizontally, and a pneumatic chuck 61 for holding a work 60 is attached to the table 18. The body 16 of the rodless cylinder 11 is attached to a table 63 of another rodless cylinder 62 substantially orthogonal to the rodless cylinder 11, and the body 64 of the rodless cylinder 62 is vertically attached to columns 65 on both sides in the longitudinal direction. It is movably mounted on Therefore, the pneumatic chuck 61 holding the work 60 can be moved in three directions of X, Y, and Z, whereby the work 60 can be moved to a desired place. FIG. 7 shows a different use mode of the present invention. In this use mode, the load positioning device 10 includes a table 68 of a rodless cylinder 67 installed substantially horizontally.
And is mounted almost vertically, and is configured as a balancer that lifts a load 69 mounted on the table 18. Since the other configuration and operation of the above-mentioned use mode are the same as those shown in FIG. 6, the same reference numerals are given to the same portions in the drawing, and detailed description will be omitted. Note that the rodless cylinders 62 and 67 in these usage modes are configured such that a piston and a table are connected by a connecting body, similarly to the rodless cylinder 10. The load positioning device according to the present invention is an improvement over the conventional positioning device, and can provide a load positioning device that can be reduced in size without any stop position error.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional front view showing an embodiment of a load positioning device according to the present invention. FIG. 2 is a cross-sectional view of the same. FIG. 3 is a vertical sectional front view of the essential part. FIG. 4 is a partially enlarged sectional view of the same. FIG. 5 is a configuration diagram of a drive system of the embodiment. FIG. 6 is a perspective view showing an example of a use mode. FIG. 7 is a perspective view of a different use mode. [Description of Signs] 12 Feed screw 13 Electric motor 16 Body 17 Piston (moving member) 18 Table 19 Slit 20 Connecting body 26, 27 Screw groove 29 Ball 48 Guide 49 Dust seal

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Claims (1)

Claims: 1. A body, a table movable along an outer surface of the body in a longitudinal direction of the body, a guide provided on the body to guide movement of the table, A feed screw provided in the longitudinal direction thereof and rotatably supported by the body, an electric motor mounted on a shaft end of the feed screw so as to integrally rotate a rotor, and the feed screw penetrates; A moving member that moves in the body by the rotation of the feed screw, a connecting body that connects the moving member and the table through a slit formed in the body, and a slit that is inserted through the table and is positioned outside the slit; And a belt-shaped dust seal that covers the load, and the load can be stopped at the target stop position by moving the table by rotating the feed screw by the electric motor. Positioning device to load.