WO2005037691A1

WO2005037691A1 - Free ball bearing and supporting table

Info

Publication number: WO2005037691A1
Application number: PCT/JP2004/015234
Authority: WO
Inventors: Kaoru Iguchi
Original assignee: Iguchi Kiko Co., Ltd.
Priority date: 2003-10-17
Filing date: 2004-10-15
Publication date: 2005-04-28
Also published as: JP2005119838A; CN1867504A; CN1867504B; TW200521349A; KR20060073634A

Abstract

A free ball bearing (1, 11), comprising a body (2, 12) with a semi-spherical recessed face, a large number of small balls (3, 13) disposed in the semi-spherical recessed face of the body, a large ball (4, 14) placed on the large number of small balls, and a cap (5, 15) preventing the large ball and the small balls from being ejected. At least the large ball is formed of a conductive resin, and the small balls, the body, and the cap are formed of the conductive resin or a metal.

Description

Free Ball Bearing and Support Table Technical Field

The present invention relates to a free ball bearing having a structure that receives a load with a single ball that is rotatable in all directions, and is suitable for a support table such as a transporting / positioning table of a load, and in particular, The present invention relates to a free ball bearing and a support table using the same, which do not cause static electricity damage to a load.

Priority is claimed on Japanese Patent Application No. 2003-358532, filed on October 17, 2003, the content of which is incorporated herein by reference.

Background art

[0002] A device for transporting and positioning a workpiece in a production factory or the like is based on a free ball bearing having a structure in which one ball is rotatable in all directions and directly contacts a load. There are cases where a large number of units are arranged on a table to form a support table such as a transport / positioning table that enables smooth movement of the load.

The structure of the free ball bearing is basically the same as that of the embodiment of the present invention shown in FIG. 1 in appearance, except that a large number of small balls are arranged on a hemispherical concave surface formed in the main body. One large ball is placed on the large ball so as to be rotatable in all directions, and a cap is provided to prevent the large and small balls from jumping out. The transfer table using this free pole bearing is capable of moving in any direction and changing its posture, and has extremely low frictional resistance to the load, so it can be strictly protected from scratches or has high positioning accuracy. For example, it is used in production lines that require the securing of glass substrates.For example, glass table transport tables in glass sheet processing lines, and glass substrate transport lines in flat panel display (FPD) production lines such as liquid crystal panels. · Used for positioning tables, etc.

[0003] In this type of conventional free ball bearing, generally, a large ball, a small ball, a main body, and a cap are all made of metal. However, some loaded items are easily damaged by contact with metal, so large balls are mainly made of synthetic resin to prevent damage. There is also one (see Patent Document 2).

Patent Document 1: Patent No. 2641187

Patent Document 2: Japanese Patent Application Laid-Open No. 7-164078

Disclosure of the invention

Problems to be solved by the invention

[0004] Meanwhile, for example, in an FPD production line, if a glass substrate such as a liquid crystal glass plate is charged with static electricity, so-called electrostatic breakdown may occur in a mounted device, and the yield is reduced. For this reason, it is necessary to avoid charging of the glass substrate, and various measures against static electricity are taken in each process of the production line.However, conventionally, measures against static electricity in each process of the FPD production line must be taken. Mainly, countermeasures against static electricity damage during transport between processes are, for example, taking measures against the storage shelves that hold and transport glass substrates. O

[0005] In the case of a conventional free ball bearing made of a synthetic resin, it is effective in preventing damage. However, since a synthetic resin, which is an insulator, is easily charged with static electricity, a free ball bearing and glass in contact with the free ball bearing are generally used. The substrate may become charged, causing static electricity damage to devices on the glass substrate.

In the case of a general metal free ball bearing, there is no problem that the free ball bearing itself is charged.However, when the free ball bearing comes into contact with an already charged glass substrate, the charge on the glass substrate is instantaneously moved. As a result, there is a possibility that electrostatic breakdown of the device may occur.

[0006] As described above, in conventional FPD production lines and the like, countermeasures against static electricity in the transfer apparatus itself are not considered much, but in recent years more strict measures against static electricity have been required. There is a need for countermeasures against static electricity.

[0007] The present invention has been made in view of the above background, and an object of the present invention is to provide a free ball bearing capable of forming a support table that does not cause static electricity damage to a load, and a support table using the same.

Means for solving the problem

[0008] The present invention for solving the above-mentioned problems provides a main body having a hemispherical concave surface, and the hemisphere of the main body. A free ball bearing comprising: a plurality of small balls arranged on a concave surface; one large ball placed on the large number of small balls; and a cap for preventing the large and small balls from jumping out, A free ball bearing is provided in which at least the large ball is made of conductive resin and the small ball, the main body and the cap are made of conductive resin or metal.

In this case, only the large ball can be made of conductive resin, and the small ball, the main body and the cap can be made of metal. Further, the large ball, the main body and the cap can be made of conductive resin, and the small ball can be made of metal. Further, all of the large ball, small ball, main body and cap can be made of conductive resin.

Further, a screw shaft for mounting may be integrally provided on the lower surface of the main body, and the screw shaft may be made of conductive resin or metal.

As the conductive resin constituting the large ball or the like, a conductive resin (conductive resin molded product) having a surface resistivity of 10 ³ —ιο1 ⁽⁾ Ω is suitable.

[0009] Here, the conductive resin has a broad meaning in comparison with the insulating resin, and includes a so-called semiconductive resin and a narrowly defined conductive resin.

Generally, a synthetic resin having a volume resistivity of about 10 ¹³ Ω << η or less can be said to be a conductive resin in a broad sense in comparison with an insulating resin. Among them, those with a volume resistivity of about 10 ⁵ — 10 ¹³ Ω «η can be called semiconductive resins, and those with a volume resistivity of about 10 ⁵ — 10 ^{1 (>} Ω« η) Is also referred to as antistatic resin as a semiconductive resin suitable for controlling electrostatic damage.In this sense, the conductive resin (conductive resin) constituting a large ball or the like in the free ball bearing of the present invention. Resin molded product) can also be referred to as conductive, antistatic resin.

[0010] The present invention also provides a support table for distributing and mounting a plurality of the free ball bearings on a horizontal base, and receiving a load movably in an arbitrary direction in a horizontal plane. A support table is provided in which at least a portion of the base that contacts the free ball bearing is a grounded good conductor. The invention's effect

[0011] According to the free ball bearing or the support table of the present invention, the load is directly applied to the load. Since the contacting large ball is made of resin, it is possible to prevent the load from being damaged. In addition, the resin is a conductive resin (conductive resin in a narrow sense) ¾v, which is not an insulating resin, and is a semiconductive resin. Therefore, the loaded material is not charged by contact with the loaded material. Also, when the load is already charged, the charge of the load is removed at a relatively slow charge transfer speed, unlike the case where the load is made of a highly conductive metal. In this way, antistatic is achieved, and there is an obstacle due to the electrification itself! /, Which can prevent electrostatic damage such as electrostatic destruction due to rapid static elimination.

In this case, the value of the surface resistivity may be appropriately selected according to the use or the properties of the load. When it comes into contact with a semiconductor device, for example, 10 ⁶ — ιο1 ⁽⁾ ΩΖ has a good surface resistivity. In the case of contact with the glass substrate of the FPD, the range can be expanded.

In this case, the static elimination performance largely depends mainly on the properties (surface resistivity) of the conductive or semiconductive resin, and when only the large ball is made of conductive or semiconductive resin, When only the main body and cap are made of conductive or semi-conductive resin, when large balls, small balls, main body and cap are made of conductive or semi-conductive resin (all remaining parts are By appropriately selecting (metal), the static elimination performance can be appropriately set.

When the screw shaft for mounting is integrally provided on the lower surface of the main body, both the lower surface of the main body itself and the screw shaft serve as a charge transfer path, which is effective for static elimination performance.

In addition, when all parts including the large ball as well as the small ball, the main body and the cap are made of the same material, there is an advantage when used in a strict clean room. In other words, even if dust is generated due to the abrasion and the like of the free ball bearing that constitutes the transfer / positioning table, one type of dust will be generated if the same material is used. (Identification of what material it is) is easy, and therefore clean room mosquitoes and waste disposal are easy.

Brief Description of Drawings

FIG. 1 is a diagram showing a free ball bearing according to a first embodiment of the present invention in two parts, a front view and a sectional view. FIG. 2 is a perspective view showing a part of a transfer / positioning table (support table) using the free ball bearing of FIG. 1.

FIG. 3 is a graph showing static elimination characteristics measured for the free ball bearing of the first embodiment.

FIG. 4 is a diagram showing a free ball bearing of a second embodiment divided into a front view and a sectional view.

Explanation of symbols

[0013] 1, 11 free ball bearings

2, 12 body

2a, 12a hemispherical concave surface

3, 13 small ball

4, 14 Great Beaune

5, 15 cap

5a, 15a opening

5b circumferential groove

15b flange 咅

15c Mounting hole

7 base

8 Transport · Positioning table (support table)

16 Washer

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a free ball bearing and a support table embodying the present invention will be described with reference to the drawings.

Example 1

FIG. 1 is a diagram showing a free ball bearing 1 according to an embodiment of the present invention in two parts, a front view and a sectional view. The main body 2 of the free ball bearing 1 has a cylindrical shape having a hemispherical concave surface 2a on the upper surface, and is integrally provided with a screw shaft 2b on the lower surface for attaching to a transfer / positioning table described later. Then, a large number of small balls 3 are arranged on the hemispherical concave surface 2a of the main body 2, and one large ball 4 is placed thereon, and the large ball 4 can be rotated in all directions. Noh holds. In addition, a cap 5 having an opening 5a for projecting the top of the large ball 4 is attached so as to cover the main body 2 from above, thereby preventing the large ball 4 and the small ball 3 from flying out. . The cap 5 has a locking projection 5b at the lower end edge for engaging with a circumferential groove 2c formed on the outer periphery of the main body 2, thereby preventing detachment.

[0016] The free ball bearing 1 has the same external force as the conventional one in the present invention. In the present invention, at least the large ball is made of a conductive material having a surface resistivity of 10 ³ -10 ^{1 (>} Ω) (in a narrow sense). It is made of semi-conductive resin.

Specifically, for example, only the large ball 4 can be made of a conductive or semiconductive resin, and the small ball 3, the main body 2, and the cap 5 can be made of a metal. In addition, the large ball 4, the main body 2, and the cap 5 can be made of conductive and semiconductive resin, and the small ball 3 can be made of metal. Further, all of the large ball 4, the small ball 3, the main body 2 and the cap 5 can be made of conductive or semiconductive resin.

In the free ball bearing 1 of the embodiment, a screw shaft 2b as a mounting portion is integrally formed on the lower surface of the main body 2. Therefore, the screw shaft 2b is made of the same conductive or semiconductive resin as the main body 2, but it is also possible to form the screw shaft separately. In that case, the screw shaft can be made of metal.

In the present invention, as means for obtaining a conductive semi-conductive resin, that is, means for imparting conductivity to a base resin which is an insulating material, metal or metal is added to the base resin. There are a method of dispersing a conductive filler such as a carbon material, a method of adding an antistatic polymer to a base resin, and the like, and the means for imparting conductivity is arbitrary. However, it is not appropriate to coat the surface with an antistatic agent. Further, the type of the conductive filler or the antistatic polymer for imparting conductivity is not particularly limited. It is advisable to select an appropriate one according to the value of the surface resistivity to be obtained, the base resin used, and other various conditions.

[0019] The base resin of conductive! / Semi-conductive resin is PAI (polyamideimide), PBI (polybenzimidazole), PCTFE (polychloro trifluoroethylene), PEEK (polyether ether). Ketones), PEI (polyetherimide), PI (polyimide), PPS (polyphenylene sulfide), melamine resin, aromatic polyamide resin (aramid resin) and the like can be used. Also, LCP (liquid crystal polymer), PBT (polybutylene terephthalate), PES (polyether sulfone), and other resins can be used. Vespel (a registered trademark of DuPont, which is an aromatic polyimide resin) and PEEK are suitable as V and resin for the free ball bearing.

[0020] The small ball 3, the main body 2, the cap 5 and the like can be made of metal in some cases. When metal is used, stainless steel or steel can be used.

For example, as shown in FIG. 2, a large number of the above-mentioned free ball bearings 1 are distributed and mounted on a horizontal base 7 to form, for example, a transporting / positioning table 8. The transfer positioning table 8 functions as a transfer table between glass substrate processes in the FPD production line, and also functions as a positioning table that allows a minute movement after reaching each process. The free ball bearing 1 is attached to the base 7 by screwing the screw shaft 2b into the screw hole formed in the base 7.At least the portion of the base 7 that comes into contact with the free ball bearing 1 (i.e., the screw shaft 2b is screwed in). The screw hole portion and / or the lower surface portion of the main body 2 are made of a good metal conductor and are grounded.

In the transporting / positioning table 8 configured as described above, the large ball 4 of the free ball bearing 1 is free to roll on a large number of small balls 3 in an arbitrary direction with extremely small frictional resistance. A load such as a glass substrate (indicated by reference numeral 9 in FIG. 1) placed on the point contact can be moved in an arbitrary direction in a horizontal plane and with extremely small frictional resistance. And since the large ball 4 which comes into contact with the load is made of resin, it is possible to prevent the load from being damaged. At least the large ball 4 is made of a conductive or semiconductive resin, which effectively prevents the occurrence of static electricity damage to the load, as described below. it can.

In the structure shown in FIG. 1, the large ball 4 is composed of a resin molded product (using the above-mentioned Vespel) having a surface resistivity of 10 ^{4 to} 10 ⁵ Ω / mouth, and the small ball 3, the main body 2 and For the free ball bearing according to one embodiment of the present invention in which the cap 5 is made of stainless steel, and for comparison, a free ball bearing entirely made of ordinary insulating resin, the following measurements were made. Was performed. Three free ball bearings were mounted on the insulator base, and the free ball bearing body was grounded. Electrostatic charges on the large balls 4 of these free ball bearings Immediately before the measurement by the generator, a glass substrate of 50mmX50mmX0.7mm charged to about 1200V was placed, and the static electricity measuring device was brought close to the glass plate to measure the change of the electrostatic voltage of the glass plate.

The measurement results are as shown in the static elimination characteristic diagram of FIG. 3, where the horizontal axis is time (seconds) and the vertical axis is voltage (V). In the figure, the symbol ▲ (B-2) indicates the case of a conventional free ball bearing using insulating resin, and the symbol ♦ (B-1) indicates the case of the free ball bearing of the present invention. As is clear from FIG. 3, in the conventional free ball bearing made of insulating resin, even after 60 seconds, the electrostatic voltage was about 90% of the initial voltage, and almost no electricity was discharged. In the case of free ball bearings made of semiconductive resin, the electrostatic voltage gradually decreases to about 10% in about 30 seconds. When the small ball 3, the main body 2, and the cap 5 are also made of a conductive or semiconductive resin, it is presumed that the charge is more gradually removed. Therefore, according to the free ball bearing of the present invention, it is possible to prevent, for example, in a FPD production line, the occurrence of static electricity failure when carrying and positioning the glass substrate.

Example 2

In the present invention, the structure of the free ball bearing is not limited to that of the above embodiment, and may be, for example, a structure as shown in FIG. The illustrated free ball bearing 11 has basically the same basic structure as that of FIG. 1, and a large number of small balls 13 are arranged on the hemispherical concave surface 12 a of a main body 12 having a hemispherical concave surface 12 a. And a cap 15 having an opening 15a for projecting the top of the large ball 4 and a flange 15b for attachment, on which one large ball 14 is mounted so as to be rotatable in all directions. The free ball bearing 11 is fixed by placing the bolt on the body 12 from above with the washer 16 in between, and tightening the bolt that has passed through the mounting hole 15c drilled in the flange 15b into the screw hole on the base side. It is. Washers 16 prevent small balls 13 from jumping out, and caps 15 prevent large balls 14 from jumping out.

In this free ball bearing 11, as described above, at least the large ball 14 is made of conductive! / Semi-conductive resin, and the other parts are conductive! / Semi-conductive resin. Or composed of metal.

The structure of the free ball bearing itself may take various other forms. A main body having a spherical concave surface, a large number of small balls disposed on the hemispherical concave surface of the main body, one large ball placed on the large number of small balls, and preventing the large ball and the small ball from jumping out. Any structure having a cap may be used. In addition, various shapes of the cap are conceivable, but in short, any shape can be used as long as the large ball and the small ball can be prevented from jumping out. Various means for attaching to the base are conceivable. Furthermore, a structure in which a plurality of free ball bearings are integrally formed, for example, a structure in which a plurality of hemispherical concave surfaces are formed in one common body to form a plurality of free ball bearings having a common body.

[0025] The free ball bearing of the present invention can be applied as a simple transfer table or as a simple positioning table, which is suitable for use as a positioning table for transferring and positioning a glass substrate in an FPD production line. The present invention can be applied to various support tables in a case where a smooth movement of an object in a horizontal plane is required.

In addition, the load is not limited to glass substrates and can be applied to various articles that dislike static electricity and are inconvenient for instantaneous static elimination, such as transfer tapes for semiconductor wafers and other electronic equipment manufacturing equipment. It can be applied to any support table.

[0026] In addition, when the load is merely an object that dislikes static electricity and does not cause a problem of instantaneous static elimination, at least a large ball is made of a conductive material having a low surface resistivity of 10 ³ Ω or less. Other components such as small balls, a main body and a cap can be made of metal or conductive resin having a low surface resistivity of 10 ³ Ω or less.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Additions, omissions, substitutions, and other modifications of the configuration can be made without departing from the spirit of the present invention. The present invention is limited only by the scope of the appended claims rather than by the foregoing description.

Industrial applicability

[0028] The free ball bearing and the support table using the same according to the present invention can be suitably used for a support table such as a positioning table for carrying a load. In particular, the free ball bearing of the present invention and the supporting table using the same are particularly effective in preventing the load from being damaged by static electricity. This is suitable for the case where! / ヽ is prevented.

Claims

The scope of the claims

[1] A main body having a hemispherical concave surface, a number of small balls disposed on the hemispherical concave surface of the main body, one large ball placed on the number of small balls, A free ball bearing with a cap to prevent the ball from popping out,

A free ball bearing in which at least the large ball is made of conductive resin, and the small ball, the main body, and the cap are made of conductive resin or metal.

2. The free ball bearing according to claim 1, wherein a screw shaft for mounting is integrally provided on a lower surface of the main body, and the screw shaft is made of conductive resin or metal.

[3] The free ball bearing according to claim 1, wherein each component made of the conductive resin has a surface resistivity of 10 ^{3 to} 10 ^{1 (>} Ω).

[4] A support table, wherein a plurality of the free ball bearings according to claim 1 are distributed and mounted on a horizontal base, and the loaded table movably receives a load in an arbitrary direction in a horizontal plane. A support table in which at least a portion of the table that contacts the free ball bearing is a grounded good conductor.