JPH07122455B2 - Precision positioning device - Google Patents

Description

Detailed Description of the Invention 【Technical field】

The present invention relates to a precision positioning device used for an XY table or the like.

[Background technology]

When moving a slide table that is slidably supported in an XY table, etc., it is generally moved directly by a linear drive device such as a feed screw mechanism or a linear motor. This is unsuitable when a runout or rattling in a radial direction other than the driving direction is transmitted to the slide table and precise positioning is required. For this purpose, as shown in FIG. 5, a movable body 2 which is linearly driven by a linear drive device (not shown) is provided, and a plate 29 protruding from the movable body 2 is protruded from the slide table 1. The one positioned between the pair of nozzle plates 18 and 19 is proposed in Japanese Patent Laid-Open No. 59-71712.
Both nozzle plates 18 and 19 here are provided with a nozzle 17 that ejects high-pressure air toward the plate 29, and constitutes a gas bearing between the nozzle plate 18 and the plate 29. However, this one has the following problems.
First, even in the case of the gas bearing, since the force is transmitted through the entire bearing surface, the slide table 1 is affected by the deviation of the parallelism between the slide table 1 and the movable body 2 and the displacement and fluctuation of the movable body 2 due to the linear drive device. It appears as pitching or yawing, which causes a positioning error. Since the second rigidity per unit area is low, a large gas bearing is required to transmit a large force, and it is impractical when high-speed positioning is required. The third problem is that in the gas bearing, there are many design factors such as the diameter and arrangement of the nozzle 17, clearance, air pressure, etc., and it is necessary to determine the optimum design value each time according to the operating conditions. Sex is limited. However, JP-A-61-293745 and JP-A-61-293746
As disclosed in Japanese Patent Publication No. JP-A-2003-264, there is a device in which a roller or a sphere is interposed between a slide table and a movable body, and the two are attracted to each other by a permanent magnet or a coil spring. Is almost solved. However, since a plurality of rollers and spheres are used, it is not perfect in that the rotational displacement around the axis in the direction orthogonal to the sliding direction is transmitted to the slide table, and also in these cases, the second The problem and the third problem have not been solved, and there remain problems in terms of large force transmission, design freedom, and versatility. This is because the spring force of the coil spring and the attractive force of the permanent magnet cannot be changed unless the design is changed and parts are replaced.

[Object of the Invention]

The present invention has been made in view of the above points, and an object thereof is to be able to transmit a large force in the sliding direction, and at the same time, to transmit the movement in the other direction to the slide table. Another object is to provide a precision positioning device that enables high-speed precision positioning.

DISCLOSURE OF THE INVENTION

Therefore, the precision positioning device according to the present invention connects the slide table slidably supported, the movable body that is slid driven by the linear drive device, and the movable table and the slide table that have the same sliding direction. And a transmission member for transmitting the movement of the movable body to the slide table. The transmission member is rotatably disposed between the surfaces of the movable body and the slide table which face each other in the sliding direction, and the transmission member is provided between the movable body and the slide table. A single spherical body that is in contact with both of the opposing surfaces, and a connecting rod that is connected at both ends to the movable body and the slide table via universal joints and that pulls the movable body and the slide table together with the spherical body sandwiched therebetween. And a universal joint at least one end of the connecting rod is a slide member provided on a movable body or a slide table. Is characterized in that it is connected to a spring arm deflectable countercurrent. According to the present invention, the sphere located between the movable body and the slide table prevents the transmission of unnecessary force, and although the connecting rod is used for reaching because of the large pulling force, The existence of the spring arm ensures the reliable movement of the sphere, and the existence of the universal joint prevents the influence of the movement other than the sliding direction from being transmitted through the connecting rod. Hereinafter, the present invention will be described in detail with reference to the illustrated embodiment. One end of an arm 11 and one end of a spring arm 12 are fixed to a slide table 1 slidably supported by a slide guide 10. Further, a spherical body 3 which is a steel ball that has been quenched through a ball guide 15 is rotatably held on a side surface of the arm 11. The movable body 2 slidably supported by the sub-slide guide 20 is linearly driven by a linear drive device 5 which is a linear motor arranged in the sub-slide guide 20, and its sliding direction is the sliding direction of the slide table 1. It is parallel to the sliding direction. One end of the arm 21 protruding toward the slide table 1 is fixed to the movable body 2. This arm 21 has its side surface opposed to the arm 11 in the sliding direction of the slide table 1, and the sphere 3 has both arms 11, 21 as shown in FIG.
It comes into contact with the side surface that has been subjected to the quenching process and the polishing process. The arm 21 is connected to the spring arm 12 by a connecting rod 4. The connecting rod 4 here has a right-hand threaded portion called a turnbuckle or a rod end and a left-handed threaded portion, and its length is freely adjustable, and both ends enclose a spherical body and this. They are connected to the arm 21 and the spring arm 12 via universal joints 40, 40 each having a degree of freedom in the three-dimensional direction including a bearing. FIG. 3 shows an example in which a feed screw mechanism constituted by a feed screw 50 rotatably driven by a motor 52, a feed nut 51, a guide shaft 53 and the like is used as the linear drive device 5. Thus, in this precision positioning device, the connecting rod 4
By adjusting the length of the spring arm 12 so that the spring arm 12 is bent, the movable body 2 and the slide table 1 sandwiching the sphere 3 between the arms 11 and 21 are attracted to each other, and the sliding direction of the slide table 1 is increased. At, a preload state is formed in which the sphere 3 contacts the arms 11 and 21 at a required pressure. Now, when the movable body 2 makes a linear motion by being driven by the linear drive device 5, the movable body 2 pushes the slide table 1 through the spherical body 3 and pulls it through the connecting rod 4,
The slide table 1 is moved. At this time, even if the movable body 2 moves in the radial direction or around the axis intersecting the linear movement direction, these must be the rolling of the spherical body 3, the existence of the universal joint 40, and that only one spherical body 3 exists. Since it is absorbed by, for example, it is not transmitted to the slide table 1, and the slide table 1 does not cause pitching or yawing. Actually, the rolling resistance of the spherical body 3 and the rotational resistance of the universal joint 40 cause unnecessary movements to the slide table 1, but these are sufficiently smaller than the force to be transmitted in the sliding direction, and are practically used. There is no problem if you ignore it. The spring arm 12 acting as a leaf spring element can generate a sufficiently large force by appropriately selecting its plate thickness, so that the presence of the spring arm 12 limits the magnitude of the force to be transmitted. It is hardly given, and it is possible to cope with high-speed, high-acceleration positioning in which a large inertial force acts. In the illustrated example, the spring arm 12 is provided on the slide table 1 side, but it is of course possible to provide it on the movable body 2 side, and the spring arms provided on both sides may be connected by the connecting rod 4. Good.

【The invention's effect】

As described above, in the present invention, the components other than the necessary components of the movement of the movable body can be absorbed by rolling of the spherical body or rotation of the free joint, and in particular, the spherical body is a single body. Therefore, the rotational displacement around the axis orthogonal to the slide direction is not transmitted to the slide table side, and only the required component movement can be transmitted to the slide table via the spherical body or the connecting rod. With the elasticity of the spring arm, the sphere comes into contact with the movable body and the slide table at a required pressure in the slide direction, so that the slide table can be precisely positioned without rattling in the slide direction. Moreover, since the slide table is driven by the movable body by the spherical body or the connecting rod and the spring arm, Force greater can be transmitted, is thus one that can cope with high-speed positioning.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention, FIG. 2 is an exploded perspective view of the same as above, FIG. 3 is a perspective view showing another example of the linear drive device of the same above, and FIG. 5 is a perspective view of a conventional example, 1 is a slide table, 2 is a movable body, 3 is a sphere, 4 is a connecting rod, 5 is a linear drive device, 12 is a spring arm,
40 indicates a free joint.

Claims (2)

[Claims] 1. A slide table supported slidably, a movable body which is slidably driven by a linear drive device, and the movable body and the slide table, which have the same sliding direction, are connected to each other to move the movable body. A transmission member for transmitting to the slide table, wherein the transmission member is rotatably disposed between the facing surfaces of the movable body and the slide table in the sliding direction so that the movable body and the slide table face each other. A single sphere that is in contact with the surface together, and a connecting rod whose both ends are connected to the movable body and the slide table through universal joints, respectively, and the movable body and the slide table are pulled together by sandwiching the sphere, The universal joint on at least one end of the connecting rod is a spring arm provided on a movable body or a slide table and capable of bending in the sliding direction. Precision positioning apparatus characterized by being connected to the arm. 2. The precision positioning device according to claim 1, wherein the connecting rod is a turnbuckle, rod end or the like whose length is adjustable.