JP2006177499A - Ball transfer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ball transfer maintaining smooth operation without interposing a lubricating oil therein. <P>SOLUTION: This ball transfer 10 comprises: a case 11 having a bearing surface 12; a plurality of small balls 15 disposed on the bearing surface 12; and a large ball 16 rotatably supported on the bearing surface 12 through the small balls 15. A carried object placed on the large ball 16 is moved by the rotation of the large ball 16. A DLC coating film 20 of an amorphous structure formed mainly of carbons is formed on the surface of the bearing surface 12 of the case 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an improvement of a ball transfer used for, for example, transporting a heavy object 360 degrees freely in a horizontal direction.

  The ball transfer includes a case having a bearing surface, a large number of small balls arranged on the bearing surface, and a large ball supported rotatably on the bearing surface via the small balls. The transported object placed on the large ball moves as the large ball rotates.

Patent Document 1 discloses a configuration for sucking and discharging dust generated inside a ball transfer.
JP 2003-184871 A

  However, in the conventional ball transfer, it is indispensable that the lubricating oil is interposed in the sliding portion of the ball transfer, and it is necessary to supply the oil frequently, so that the lubricating oil is scattered around and causes contamination. was there.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a ball transfer capable of maintaining a smooth operation without interposing lubricating oil.

  The present invention includes a case having a bearing surface, a plurality of small balls disposed on the bearing surface, and a large ball that is rotatably supported via the small balls with respect to the bearing surface. This is applied to a ball transfer that is configured such that a transported object placed on a large ball moves by rotating.

  A DLC coating film made of an amorphous structure mainly composed of carbon is formed on at least one surface of the bearing surface of the case and the small balls and the large balls.

  According to the present invention, the ball transfer has a structure in which a DLC coating film having a high hardness is formed on at least one surface of a bearing surface of a case and a small ball and a large ball that are in sliding contact with each other. The frictional force acting on the sliding portion of the ball transfer can be reduced, the mechanical efficiency of the ball transfer can be increased, and the life of the ball transfer can be extended. Furthermore, noise generated from the ball transfer can be reduced.

  Furthermore, since the ball transfer can ensure smooth operability without supplying lubricating oil, it can be operated in an oil-free state. As a result, the ball transfer can be used in a clean room, for example, by preventing the lubricating oil from scattering or generating dust from the lubricating oil.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  As shown in FIG. 1, the ball transfer 10 includes a case 11 having a bearing surface 12, a plurality of small balls 15 disposed on the bearing surface 12, and the bearing surface 12 via the small balls 15. The large ball 16 is rotatably supported. A large number of ball transfers 10 are provided side by side with a predetermined interval on a conveyance path (not shown), and a conveyed product is placed on the large balls 16 of each ball transfer 10, and the large balls 16 rotate to move the conveyed items. It is supposed to be.

  A screw 13 protrudes from the lower surface of the case 11 and is fastened to a structure provided on a conveyance path (not shown) via the screw 13.

  The bearing surface 12 has an annular portion that is recessed in a spherical shape, supports the large balls 16 with a large number of small balls 15, and the small balls 15 circulate as the large balls 16 rotate. Yes.

  The DLC coating film 20 made of an amorphous structure mainly composed of carbon is formed on the surface of the bearing surface 12 of the case 11 as the gist of the present invention. The thickness of the DLC coating film 20 is, for example, about several μm or less.

  The DLC coating film 20 is formed by an unbalanced magnetron sputtering method (hereinafter referred to as “UBM sputtering method”).

  As shown in FIG. 3, the principle of sputtering is that a plasma is formed by glow discharge between an anode and a target 41 in a vacuum into which an inert gas such as argon is introduced. The atoms of the target 41 are blown off by being collided with each other, and the atoms are deposited on the work (case 11) 21 arranged to face the target 41 to form a film.

  In the UBM sputtering method, magnetic fields 42 and 43 having different magnetic characteristics in the central portion and the peripheral portion of the target 41 are arranged in the sputter evaporation sources 40a to 40d, and one of the lines of magnetic force generated by the strong magnetic field 42 while forming plasma. When the part reaches the vicinity of the workpiece 21 and a bias voltage is applied to the workpiece 21, the substance constituting the target material 41 is deposited on the workpiece 21.

  FIG. 4 shows a basic configuration of the UBM sputtering apparatus 50. Four sputter evaporation sources 40a to 40d are provided in the vacuum chamber 51, the work 21 is placed on a self-revolving work table 56 disposed in the center thereof, and the work 21 is coated. A flat target as a film material is attached to the sputter evaporation sources 40a to 40d. The vacuum chamber 51 is filled with a predetermined amount of an inert gas such as argon and a hydrocarbon gas such as methane gas.

  Sputter evaporation sources 40a and 40c use graphite as a target, and sputter evaporation sources 40b and 40d use metal as a target.

  As shown in FIG. 2, the DLC coating film 20 has a nickel plating layer 61 formed on the surface of the stainless steel workpiece 21, and a bond layer 62, an intermediate layer 63, and a top layer 64 are sequentially laminated on the surface of the nickel plating layer 61. Formed.

  FIG. 5 shows how the target output changes when the DLC coating film 20 is formed.

  The bond layer 62 is formed as a metal film by sputtering only the metal targets 40b and 40d. In forming the bond layer 62, as shown in FIG. 5, the metal target output of the sputter evaporation sources 40b and 40d is set to 100%, and the graphite target output of the sputter evaporation sources 40a and 40c is kept constant at 0%. Sputtering is performed for a predetermined time.

  The intermediate layer 63 is formed as a gradient composition film of metal and carbon by simultaneously sputtering the metal target of the sputter evaporation sources 40b and 40d and the graphite target of the sputter evaporation sources 40a and 40c, and gradually changing the target output. In forming the intermediate layer 63, as shown in FIG. 5, the metal target output of the sputter evaporation sources 40b and 40d is temporarily reduced from 100%, while the graphite target output of the sputter evaporation sources 40a and 40c is reduced to 0. Sputtering is performed for a predetermined time with a primary increase from%.

  The top layer 64 simultaneously sputters the metal target of the sputter evaporation sources 40b and 40d and the graphite target of the sputter evaporation sources 40a and 40c to make the target output substantially constant, and the sputter evaporation sources 40b and 40d and the sputter evaporation source 40a. , 40c, sputtering is performed for a predetermined time while keeping the sputtering rate of the graphite target within a predetermined range.

  In forming the top layer 64, as shown in FIG. 5, the metal target output of the sputter evaporation sources 40b and 40d is about 10%, and the graphite target output of the sputter evaporation sources 40a and 40c is kept constant at about 90%. The ratio of the metal contained in the top layer 64 is set in the range of 3 to 18%. More desirably, the ratio of the metal contained in the top layer 64 is set in the range of 3 to 12%.

  Next, the operation will be described.

  After forming the nickel plating layer 61 on the surface of the work 21 made of stainless steel, the bond strength of the DLC coating film 20 with respect to the base material can be increased by providing the bond layer 62 with a metal ratio of 100%.

  An intermediate layer 63 made of a gradient composition film of metal and carbon that gradually reduces the metal ratio is provided on the bond layer 62 having a metal ratio of 100%, and a top layer 64 mainly composed of carbon is formed on the intermediate layer 63. By providing, the bonding strength of the top layer 64 in the DLC coating film 20 can be increased.

  By setting the metal ratio of the top layer 64 in the range of 3 to 18%, the adhesion and toughness of the top layer 64 can be improved, and cracking or peeling occurs when the workpiece 21 is deformed by a high load. Can be prevented. And the fall of the hardness of the top layer 64 can be suppressed and abrasion resistance can be ensured.

  As shown in FIG. 6, the relationship between the ratio of the metal contained in the top layer 64 and the toughness and hardness increases the toughness and hardness of the top layer 64 by setting the metal ratio in the range of 3 to 18%. It is done. Furthermore, by setting the ratio of the metal contained in the top layer 64 in the range of 3 to 12%, both the toughness and hardness of the top layer 64 can be remarkably increased.

  On the other hand, conventionally, since the ratio of the metal contained in the top layer was 0%, there was a problem that adhesion and toughness were insufficient and the top layer was likely to be cracked or peeled off.

  As a result, even if the DLC coating film 20 is formed on the surface of the workpiece 21 that receives a high load, the DLC coating film 20 is prevented from being cracked or peeled off, and can be put to practical use.

  Due to the structure in which the high hardness DLC coating film 20 is formed on the surface of the bearing surface 12 of the case 11, the friction force acting on the sliding contact portion with the small ball 15 is reduced by the smooth DLC coating film 20 having a low friction coefficient, The mechanical efficiency with which the ball transfer 10 transmits power can be increased and the life of the ball transfer 10 can be extended. Furthermore, noise generated from the meshing portion of the ball transfer 10 can be reduced.

  Furthermore, the ball transfer 10 can be operated in an oil-free state because smooth operability is ensured without supplying lubricating oil. As a result, the case 11 can be used in a clean room, for example, by preventing the lubricating oil from scattering or generating dust from the lubricating oil.

  As another embodiment, the DLC coating film 20 may be formed on each surface of the small ball 15 or the large ball 16, and the same effect can be obtained.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  The present invention can be used for a ball transfer used in a transfer device, other machines, and buildings.

The side view which shows embodiment of this invention and is a ball transfer. Sectional drawing of a DLC coating film similarly. Explanatory drawing which similarly shows the principle of a sputtering method. The block diagram of a UBM sputtering device similarly. The characteristic view which shows a mode that a target output similarly changes. The characteristic view which shows the relationship between the ratio of the metal contained in a top layer, toughness, and hardness similarly.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Ball transfer 11 Case 12 Bearing surface 16 Large ball 20 DLC coating film 21 Workpiece 40a-40d Sputter evaporation source 50 UBM sputtering apparatus 61 Plating layer 62 Bond layer 63 Intermediate layer 64 Top layer

Claims (3)

A case having a bearing surface, a plurality of small balls disposed on the bearing surface, and a large ball supported rotatably on the bearing surface via the small ball, the large ball rotating In the ball transfer configured to move the transported object placed on this large ball,
A ball transfer comprising a DLC coating film formed of an amorphous structure mainly composed of carbon on a bearing surface of the case, and at least one surface of the small ball and the large ball.   2. The ball transfer according to claim 1, wherein a nickel plating layer is formed on the surface, and the DLC coating film is formed on the surface of the nickel plating layer.   The DLC coating film forms a bond layer by sputtering only a metal target on the surface, and forms an intermediate layer by simultaneously sputtering a metal target and a graphite target on the bond layer and gradually changing the target output. 2. A top layer having a metal ratio in the range of 3 to 18% is formed on the intermediate layer by simultaneously sputtering a metal target and a graphite target and making the target output substantially constant. Or the ball transfer of 2.

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