JPH0255337B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to transportation of electronic precision circuit components in a clean room or the like during a manufacturing process, and to other transportation devices using linear motors.

Prior Art In a conventional conveyance device using a linear motor, an article in a container as an object to be conveyed is placed on a conveyance pallet due to inertia force when the conveyance pallet is started or stopped during conveyance. It has been found that the product vibrates, causing damage to the product, generation of foreign matter, and adhesion of foreign matter to the product. This has been found to be a major problem, especially when a large number of silicon wafers are housed in a container (shipped) in the manufacture of semiconductor devices, as silicon wafers are thin and made of a brittle material.

Problems to be Solved by the Invention An object of the present invention is to incline the transport pallet itself on which the transported object is placed, and to transport the transported object at an incline, thereby reducing vibrations, etc. of the transported object during transport. It is an object of the present invention to provide a conveying device that can accurately convey objects with a high degree of reliability and stability.

Means for Solving Problems The present invention provides a transport pallet on which objects to be transported are placed, by making the object mounting surface of the pedestal on which the objects are placed be inclined with respect to the direction of travel, so that the objects to be transported can be easily transported. Another feature is that it can be conveyed at an angle with respect to the direction of travel.

Embodiment Hereinafter, a conveyance device which is an embodiment of the present invention will be explained as follows.
This will be explained in detail with reference to FIGS.

In the figure, W is a straight or curved object on which the object to be transported 8, specifically a container containing a large number of silicon wafers, is placed on the transport pallet 6 and transported to the destination. This conveyance path W consists of a conveyance table 1 and a conveyance duct 2 that is integrally provided in an airtight manner below the conveyance table 1. The conveyance table 1 is symmetrical about the center line of the conveyance path. It is made of a non-magnetic material such as aluminum, stainless steel, etc., and has a cross section horizontal to the top surface 1a and the side surface thereof are each provided with a nozzle 1c. The pallet is ejected to float the conveying pallet that is transported by a linear motor on the conveying path. Furthermore, linear motors 3 are installed in the center of the transport table 1 at appropriate intervals in the transport direction at the starting point, end point, and other locations of the transport path. A high-pressure duct 5 for circulating high-pressure air (compressed air) is arranged along the conveyance duct 2, and a pressure switching valve 9 is provided between the high-pressure duct 5 and the conveyance duct 2 to connect the two ducts. A compressor 7 and other pressure sources are connected to. Further, a transport pallet 6 is placed on the transport table 1, and at least the bottom of the pallet is made of steel plate, copper plate, aluminum plate, etc. so that thrust can be obtained by a linear motor. In addition to having a corresponding cross-sectional shape, this conveying pallet has a support 6b protruding from the upper part of the reaction plate 6a, and a pedestal 6c on which the transported object is placed on this support is inclined with respect to the direction of travel. It is set up so that it looks like this. Also reaction plate 6
A plurality of propulsion blades 4 are provided protruding from one end of a. In the illustrated embodiment, a total of four propulsion vanes are provided, two on the top surface of the reaction plate and one on each of the left and right sides, but the number of propulsion vanes can be determined arbitrarily. The propulsion blades are arranged with side plates 4a facing each other at a required interval,
A plurality of small blades 4b, 4b, . . . each having an angle of 45° or any other arbitrary angle are provided between the propelling blades 4a, and the propelling blades are made of plastic or the like in order to reduce the weight.

The operation of placing an object to be transported on a transport pallet pedestal and transporting it to a destination using the transport apparatus configured as described above will be described below.

First, compressed air produced by the compressor 7 is sent into the duct of the conveyance path via the high-pressure duct 5, and is ejected from the nozzle 1c above the conveyance table. This ejected high-pressure air presses the bottom reaction plate 6a of the conveying pallet 6 upward, so that the conveying pallet 6 floats up.
When a current for driving the linear motor 3 is supplied, the bottom reaction plate 6a of the conveying pallet 6 acts as a secondary side of the linear motor and obtains a propulsive force by the primary magnetic flux of the linear motor. For this purpose, the conveying pallet 6 is moved in the direction indicated by the arrow in FIG. At this time, as is clear from Figure 2, the silicon wafers in the container are always transported tilted in a fixed direction, which improves stability in the transport direction and prevents problems such as when starting or stopping the transport pallet. The inertial force reduces the vibration of the silicon wafer. Therefore, damage to the silicon wafer, generation of foreign matter, and adhesion of foreign matter to the silicon wafer can be reduced, and the silicon wafer in the container, that is, the object to be transported, can be transported stably, reliably, and accurately. In this way, steady conveyance is performed.

By the way, if the conveyed pallet is stopped at a location where the linear motor drive unit is not available for some reason (power outage, failure, etc.), the compressed air, which is slightly higher than the compressed air during steady conveyance, will be switched by the pressure switching valve 9 to propel the pallet. By spraying on the small blade 4b,
It is to be transported in the direction shown by the arrow in FIG. At this time, the compressed air may be blown out from the entire conveyance path, or the entire length of the conveyance path may be divided into several blocks, and a plurality of conveyance pallet position detection means may be appropriately arranged, and this detection means may be used to detect only the relevant block. It is also possible to eject and return to the origin while sequentially switching blocks based on signals from the position detecting means as the blocks are being transferred.

Effects of the Invention According to the present invention, the conveyance pallet does not come into contact with the conveyance table, and the conveyed objects are always conveyed while being tilted in a fixed direction. Since it does not generate dust due to vibration of objects, it is suitable for assembling electronic precision parts and pharmaceutical products that are sensitive to fine dust, and it is also possible to perform an emergency stop in a part without a drive device and return to the origin without going through other means. , no equipment costs,
It has advantages such as being simple and easy to maintain.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the conveying device of the present invention, FIG. 2 is a side view showing the first embodiment, and FIG.
The figure is a plan view showing essential parts of the first embodiment, and FIG. 4 is a sectional view thereof. 1...Transportation table, 2...Transportation duct, 3...
... Linear motor, 4 ... Propulsion vane, 5 ... High pressure duct, 6 ... Transport pallet, 7 ... Compressor, 8 ... Transported object, 9 ... Pressure switching valve.

Claims (1)

[Scope of Claims] 1. A conveyance path, a conveyance pallet configured to be movable on the conveyance path, an object to be conveyed mounted on the conveyance pallet, a levitation means for levitating the conveyance pallet with compressible gas, and In a conveyance device having a drive means for driving a conveyance pallet with a linear motor, the conveyance object is moved such that the front edge of the bottom surface of the conveyance object is lower than the rear edge of the bottom surface with respect to the traveling direction of the conveyance pallet. A conveyance device characterized by being mounted at an angle. 2. The transport device according to claim 1, wherein the object to be transported is a semiconductor wafer. 3. A pedestal provided on the transport pallet and for mounting the transported object, the pedestal is installed with the transported object mounting surface inclined, and the transported object is mounted on the mounting surface. The object to be transported is mounted so that the object to be transported is inclined so that the front edge of the bottom surface of the object is lower than the rear edge of the bottom surface with respect to the traveling direction of the transport pallet. A conveying device according to claim 1. 4. The transport device according to claim 3, wherein the object to be transported is a semiconductor wafer.