Patent Grant
7550045
The present invention relates to a metal surface coating treatment device and a surface coated metal manufacturing method. More particularly, it relates to a metal surface coating treatment device and a surface coated metal manufacturing method in technical fields in which, as in the case of coating of a metallic spherical body with a resin in manufacturing a track ball, high accuracy of uniformity of coating thickness and balance of weight, good appearance, and good feeling at the time of operation and contact are required, or a degree of freedom in design of the amount of coating and the size of coated metal is required.
A track ball is a position control unit used in various types of digital equipment such as a computer, medical apparatus, and radar console. A ball constituting the track ball is usually a metallic spherical body whose surface is coated with a resin. The track ball converts the direction of rotation and the travel distance given to the ball by a palm or finger into a pulse signal by using two detection shafts in contact with the ball and a rotary encoder. Therefore, the property of ball rotating in contact with the two detection shafts is an important condition for maintaining the detection accuracy and operability of track ball, so that high accuracy of uniformity of resin coating thickness and balance of weight is required.
The coating of a metallic spherical body with resin in manufacturing the above-described track ball has conventionally been accomplished by heat curing of resin powder or injection molding of molten resin.
In this method, however, it is not easy to dispose the metallic spherical body in the center of the ball, so that the thickness of resin coating becomes nonuniform at different places, and hence the balance of weight of ball sometimes becomes bad. Also, the amount of resin capable of being used for coating treatment and the size of metallic spherical body subjected to coating treatment are limited, and hence the degree of freedom in design is limited regarding the amount of coating and the size of metallic spherical body to be coated.
However, in this method as well, it is not easy to dispose the metallic spherical body in the center of the ball, so that the thickness of resin coating becomes nonuniform at different places, and hence the balance of weight of ball sometimes becomes bad. Also, on the surface of the metallic spherical body 10 having been subjected to coating treatment, pores are produced at locations supported by the string-form supports 14A and 14B, which not only impairs the appearance but also presents a problem in view of maintenance of detection accuracy.
An object of the present invention is to provide a metal surface coating treatment device and a surface coated metal manufacturing method capable of solving the problems with the above-described background art, providing excellent uniformity of coating thickness, good balance of weight, good appearance, and good feeling at the time of operation and contact, and having a high degree of freedom in design of the amount of coating and the size of coated metal.
The inventor of the present invention conducted studies on the above-described problems, and resultantly found that the resin coating thickness on the ball surface can be made uniform by immersing a ball in molten resin in place of heat curing of resin powder or injection molding of molten resin and that the production of pores on the ball surface after coating treatment can be prevented by the use of magnetic means such as an electromagnet in place of string-form supports, which led to the present invention. Specifically, as means for solving the above-described problems, the inventions claimed in this application are the followings.
Reference numerals used in the figures denote the followings.
1 . . . Magnetic floating means, 2A, 2B . . . Optical sensor, 3 . . . Control circuit section, 3C . . . Transmitting means, 4 . . . Housing structure, 5 . . . Movable member, 6 . . . Floating control section, 7 . . . Drive mechanism, 8 . . . Bed, 8A . . . Supporting section, 8B . . . Mounting section, 9 . . . Storage tank, 10 . . . Treated metal, 11 . . . Liquid coating material, Lu, Lu′ . . . Linear movement (upward), Ld, Ld′ . . . Linear movement (downward), 12A, 12B, 13A, 13B . . . Metal mold, 14A, 14B . . . String-form support, 21 . . . Powdery or pellet-form resin
The present invention will now be described in detail with reference to the accompanying drawings.
Referring to
The vertical moving means includes a drive mechanism 7 which is mounted with a movable member 5 and is moved linearly by an electric motor, described later, and the electric motor, not shown, for driving the drive mechanism 7. The drive mechanism 7 is provided on a pillar-shaped supporting section 8A of a bed 8, described later.
The bed 8 consists of the supporting section 8A and a mounting section 8B, and the storage tank 9 is provided on the mounting section 8B so as to be positioned under the magnetic floating means 1 in the vertical direction.
In the present invention, as the magnetic floating means 1, an electromagnet, for example, an electromagnetic holder (KE4B, manufactured by KANETEC Co., Ltd.) can be used.
The optical control means includes the optical sensors 2A and 2b which are on the housing structure 4 on the side lower than the magnetic floating means 1 to detect the approach of the treated metal 10 to the magnetic floating means 1, a control circuit section 3 for processing a signal detected by the sensor elements 2A and 2B and controlling the operation of the magnetic floating means 1, and transmitting means 3C for transmitting the feedback from the sensor 2A and the output to the magnetic floating means 1 by connecting the sensor 2A to the control circuit section 3 and connecting the control circuit section 3 to the magnetic floating means 1.
The storage tank 9 can be provided additionally with adjusting means, not shown, which makes adjustment such that at least some of the liquid coating material 11 stored in the storage tank 9 is discharged to the outside of the storage tank 9 by drawing up or draining off the liquid coating material 11, by which the liquid level is reduced in order to facilitate the pulling-up of the treated metal 10 from the storage tank 9. In this case, the adjusting means can be configured so as to make adjustment such that the liquid level is raised again by returning the liquid coating material 11 discharged once to the outside of the storage tank 9 again to the storage tank 9 after the immersed treated metal 10 has been pulled up.
As the drive mechanism 7 constituting the vertical moving means, for example, a linear guide or a ball screw can be used. Also, the vertical moving means can be provided with detecting means, not shown, for detecting the linear movement of the movable member 5, the rotation of ball screw, etc. as a signal and a control unit, not shown, for controlling the drive of the drive mechanism 7 by means of the electric motor by processing a signal detected by the detecting means.
As the treated metal subjected to treatment by the device in accordance with the present invention, iron can be cited. However, any magnetic material capable of being floated by the magnetic floating means such as an electromagnet comes under the metal to be treated in accordance with the present invention.
In manufacturing a ball for a track ball, the shape of the treated metal is spherical. However, the shape of the treated metal subjected to treatment by the device in accordance with the present invention is not limited to a sphere, and the device can be used for a metal having various shapes.
In manufacturing the ball for the trackball, as the liquid coating material used for coating treatment, for example, molten resin is used. However, in the present invention, the liquid coating material is not limited to molten resin.
In
The floated treated metal 10 is kept floating in the air just under the magnetic floating means 1 while being prevented from being attracted to the magnetic floating means 1 by the action of the optical control means consisting of 2A, 2B and 3, described later.
If the treated metal 10 is attracted to the magnetic floating means 1 and rises to approach the magnetic floating means 1, and is going to approach the magnetic floating means 1 beyond a line connecting the optical sensors 2A and 2B, which are located on the housing structure and fixed on the side lower than the magnetic floating means 1, to each other, the approach of the treated metal 10 to the magnetic floating means 1 is detected as an electrical signal by the optical detecting function of the sensors 2A and 2B.
The electrical signal detected by the function of the sensors 2A and 2B is subjected to information (signal) processing, in which sensor input information is sequentially output as control of strength with respect to the magnetic attracting operation of the magnetic floating means 1, by the control circuit section 3 relating to a closed loop constructed by (a) sensor, (b) control circuit section, and (c) magnetic floating means in that order via the transmitting means 3C such as wiring so that the treated metal 10 is not attracted to the magnetic floating means 1. and does not drop. A change in approaching state of the treated metal 10 based on an operation change of the magnetic floating means 1 due to the above-described information (signal) processing is again detected by the sensors 2A and 2B and is fed back to the control circuit section 3 to perform similar processing. Thereby, the floating of the treated metal 10 is maintained while the clearance between the treated metal 10 and the magnetic floating means 1 is kept within a predetermined range.
The drive mechanism 7 is moved linearly downward (Ld) by the drive of the electric motor, not shown, constituting the vertical moving means, and the movable member 5 mounted on the drive mechanism 7 and the floating control section 6 fixed to the movable member 5 are moved downward in association with the downward movement of the drive mechanism 7. Thereby, the treated metal 10, whose floating in the air just under the magnetic floating means 1 is maintained,. is moved downward (Ld′) in association with the downward movement of the floating control section 6 with its floating being maintained, and is immersed in the liquid coating material 11 for coating treatment of the surface of the treated metal 10, which is stored in the storage tank 9 provided under the magnetic floating means 1. The magnetic floating means 1 is subjected to the control of necessary magnetic attraction force by the control circuit section 3 so that the treated metal 10 is completely sunk in the liquid coating material 11. Therefore, the treated metal 10 is completely sunk in the liquid coating material 11 and is immersed.
After the treated metal 10 has been immersed in the storage tank 9 for a predetermined period of time enough to adhere the liquid coating material 11 of an amount capable of coating treating the surface of the treated metal 10 to the surface thereof, the magnetic floating means 1 is located at a position at which the floating action due to magnetic attraction force sufficiently reaches the treated metal 10. The positioning method is such that the floating control section 6 is still located at a position at the time when the treated metal 10 is immersed in the liquid coating material 11 without being raised once. However, the present invention is not limited to this method.
The drive mechanism 7 is moved linearly upward (Lu) by the drive of the electric motor, not shown, constituting the vertical moving means, and the movable member 5 mounted on the drive mechanism 7 and the floating control section 6 fixed to the movable member 5 are moved upward in association with the upward movement of the drive mechanism 7. Thereby, the treated metal 10 in the storage tank 9 is pulled up from the liquid coating material 11 in the storage tank 9 in association with the upward movement of the floating control section 6 by receiving the floating action of the magnetic floating means 1, so that the treated metal 10, to the surface of which the coating material 11 is adhered by immersion, is raised (Lu′) in association with the upward movement of the floating control section 6 while the floating is maintained.
The coating material 11 adhering to the surface of the pulled-up treated metal 10 is dried by drying means, not shown, and a coating is formed on the surface of the treated metal 10 by the coating material 11.
Before the treated metal 10 immersed in the liquid coating material 11 in the storage tank 9 is pulled up by the action of the vertical moving means, the liquid level of the liquid coating material 11 can be adjusted by discharging at least some of the liquid coating material 11 to the outside of the storage tank 9 by the adjusting means provided in the storage tank 9. The adjustment such that the liquid level is reduced can facilitate the pulling-up of the immersed treated metal 10.
As an example, a method for manufacturing a ball for a track ball using the present invention will be described.
In the device in accordance with the present invention, as the magnetic floating means 1, an electromagnet is used, and concretely an electromagnetic holder KE4B manufactured by KANETEC Co., Ltd. is used. As the drive mechanism 7, a linear guide is used. As the transmitting mean 3C, which is a constituent element of the optical control means, wiring is used. Also, as the liquid coating material 11, molten resin is used. Further, the storage tank 9 is provided with liquid level adjusting means. In the example described below, explanation is given by referring to the magnetic floating means 1 as the electromagnetic holder 1, the drive mechanism 7 as the linear guide 7, the liquid coating material 11 as the molten resin 11, and further the treated metal 10 as a spherical body made of iron (hereinafter referred to as “iron ball”) 10.
The device is prepared so that the electromagnetic holder 1 is in an operable state. The iron ball 10 is brought close to the electromagnetic holder 1 from under the electromagnetic holder 1, and the iron ball 10 is floated in the air by the action of the electromagnetic holder 1 and the optical control means consisting of the optical sensors 2A and 2B and the control circuit section 3. The floating is maintained.
The linear guide 7 is driven (Ld) by the electric motor relating to the vertical moving means, by which the floating control section 6 and the iron ball 10 floating in association with the floating control section 6 are moved downward (Ld′) to immerse the iron ball 10 in the molten resin 11 stored in the storage tank 9.
By the operation of the control circuit section 3, the magnetic attraction force of the electromagnetic holder 1 is weakened to completely sink the iron ball 10 in the molten resin 11.
After the iron ball 10 has been immersed for a predetermined period of time, the molten resin 11 in the storage tank 9 is drained from the storage tank 9 by the operation of the liquid level adjusting means so that about the upper half of the iron ball 10 appears above the liquid level.
By the operation of the control circuit section 3, the magnetic attraction force of the electromagnetic holder 1 is strengthened to float the iron ball 10 from the molten resin 11. The linear guide 7 is driven (Lu) by the electric motor to raise the floating control section 6 including the electromagnetic holder 1, by which the iron ball 10 is completely pulled up (Lu′) from the storage tank 9.
The iron ball 10 is left floating in the air for a predetermined period of time to dry the molten resin 11 adhering to the surface of the iron ball 10, by which a ball for a track ball, in which the surface of the iron ball 10 is coated with resin, is manufactured.
According to the present invention, since the device is constructed as described above, a surface coated metal capable of providing excellent uniformity of coating thickness, good balance of weight, good appearance, and good feeling at the time of operation and contact, and having a high degree of freedom in design of the amount of coating and the size of coated metal can be manufactured, so that the present invention is useful.
Also, according to the present invention, since the device is constructed as described above, a ball for a track ball or the like capable of providing excellent uniformity of coating thickness, good balance of weight, good appearance, and good feeling at the time of operation and contact, and having a high degree of freedom in design of the amount of coating and the size of coated metal can be manufactured, so that the present invention is useful in a field of manufacture of a pointing device including the track ball.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2001-338751 | Sep 2001 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP02/09990 | 9/26/2002 | WO | 00 | 9/20/2004 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO03/028901 | 4/10/2003 | WO | A |
| Number | Date | Country |
|---|---|---|
| 56-17568 | Feb 1981 | JP |
| 61-33671 | Feb 1986 | JP |
| 62-168566 | Jul 1987 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20050031800 A1 | Feb 2005 | US |
