JP2008274984A - Conveying roller and vacuum conveying device equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conveying roller for guiding a conveying part with its outer periphery face rotated in contact with the guided face of the conveying part, having improved durability when the guided face of the conveying part collides with the conveying roller. <P>SOLUTION: The conveying roller 1 is made in the following method: a plurality of silicon-nitride balls are put into a mill pot, shown in Fig.2, the conveying roller 1 is externally fitted to a columnar body 44, and a planetary ball mill is operated to perform a ball mill process for imparting centrifugal force following revolution generated in the mill pot and centrifugal force following rotation to the balls 5 to make the balls 5 collide with the outer peripheral face of the conveying roller 1 and introduce residual stress into a surface layer portion on the outer peripheral face, and then to perform finishing polishing work. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a transport roller that guides the transport unit by rotating an outer peripheral surface of a cylindrical body in contact with a guided surface of the transport unit, and a vacuum transport device including the transport roller.

As part of equipment for manufacturing liquid crystal display panels, semiconductor devices, solar battery panels, hard disk devices, and the like, there are vacuum processing devices such as sputtering devices, plasma CVD devices, and ion implantation devices. And these vacuum processing apparatuses are equipped with the vacuum conveyance apparatus which conveys to-be-processed goods, such as a board | substrate, in a vacuum state.
As an example of the vacuum processing apparatus, there is an in-line vacuum film-forming apparatus that forms a film on the substrate by passing a gas plasma discharge region through a transfer section where the substrate is installed. The apparatus includes a vacuum transfer device that guides a guided surface of the transfer unit with a transfer roller.

Conventionally, a transfer roller made of stainless steel (mainly SUS440C) and subjected to quenching and tempering processing is used as the transfer roller of this vacuum transfer device. As the rolling bearing for rotatably supporting the transport roller, a roller bearing made of stainless steel (mainly SUS440C) and lubricated with fluorine-based grease is used.
By the way, functions of liquid crystal display panels, semiconductor devices, solar battery panels, hard disk devices, and the like are impaired due to adhesion of fine particles (foreign matter) to the surface. Therefore, in recent years, as these devices are miniaturized and integrated, it is required to manufacture them in a highly clean environment in order to improve the yield as a product.

  In addition, reducing the cost associated with maintenance of facilities for manufacturing these products (making maintenance-free or lengthening the maintenance cycle) leads to a reduction in product manufacturing costs. Therefore, it is required to improve the durability of the above-described vacuum processing apparatus and vacuum transfer apparatus for the purpose of reducing the manufacturing cost of liquid crystal display panels, semiconductor devices, solar battery panels, hard disk devices and the like.

As a technique for meeting this requirement, the present applicant has proposed that a DLC film is provided on the outer peripheral surface of the conveying roller of the vacuum conveying device, and a lubricating film is provided on the raceway surface of the rolling bearing that supports the conveying roller (described below). Patent Document 1). In addition, it has been proposed to form a portion including an outer peripheral surface to be brought into contact with the guided surface of the conveying portion of the conveying roller with a ceramic material (see Patent Document 2 below). According to these proposals, there is a certain effect in reducing dust generation and improving durability of the vacuum transfer device, but there is room for further improvement.
For example, as shown in FIG. 1, a disk media vacuum transfer device has a rail 4a fixed to a lower portion of a carriage 4 to which a disk medium D is mounted, and the transfer roller 1 has an outer peripheral surface on the rail (guided surface) 4a. The carriage (conveyance unit) 4 is guided by rotating in contact.

  When the carriage 4 is fed from the right side to the left side of the sheet of FIG. 1, for example, by a driving device (not shown), the rail 4a is first brought into contact with the right conveyance roller 1a of the two, so that the right conveyance roller 1a starts rotating. Next, when the rail of the carriage that has moved to the left side further comes into contact with the left conveyance roller 1b, the left conveyance roller 1b starts to rotate. Then, when the traveling speed of the carriage and the rotation speed of the conveyance roller become the same, the rotation of the conveyance roller is stabilized. The durability after the stable rotation is improved by the above-mentioned proposed method, but when the contact between the rail and the transport roller starts, an impact force from the rail is applied to the transport roller. In the proposed method described above, the impact resistance at this time is insufficiently improved, and it is necessary to further improve the durability.

  In Patent Document 3 below, as a method for toughening the surface of a ceramic product, the hardness is 500 or more in terms of Hv (Vickers hardness), and is equal to or less than the value obtained by adding 50 to the Hv of the target ceramic product. A method of forming a linear dislocation structure uniformly distributed on the surface of a ceramic product is described using an injection material (shot) having an average particle size of 0.1 μm to 200 μm and a surface made of fine particles having convex curved surfaces. ing.

Further, in Patent Document 4 below, a revolving rotary arm that rotates around a revolving shaft that is rotated by a driving force, and a revolving rotary arm that is inclined from the vertical to the revolving shaft side are rotatably supported by the revolving rotary arm. And the outer peripheral surface of the mill pot which is fixedly disposed above the revolving rotary arm over the entire circumference around the revolving shaft and revolves as the revolving rotary arm rotates. There is described a planetary ball mill having an outer peripheral pot receiver that causes the mill pot to rotate.
Japanese Patent Laid-Open No. 2005-23965 JP 2006-153187 A JP 2004-136372 A JP 2006-43578 A

  An object of the present invention is to improve durability when the guided surface of the transport unit collides with the transport roller in the transport roller that guides the transport unit by rotating the outer peripheral surface in contact with the guided surface of the transport unit. It is to improve.

  In order to solve the above-described problems, the present invention provides a transport roller that guides the transport unit by rotating the outer peripheral surface in contact with a guided surface of the transport unit. Provided is a conveyance roller characterized in that a compressive residual stress of 50 MPa or more and 1500 MPa or less is introduced into the part in an absolute value. “Compressive residual stress of 50 MPa to 1500 MPa in absolute value” corresponds to “residual stress of −1500 MPa to −50 MPa”. A residual stress of “−” means a compressive residual stress.

According to the transport roller of the present invention, the compressive residual stress of 50 MPa or more and 1500 MPa or less in absolute value is introduced into the surface layer portion of the outer peripheral surface that rotates in contact with the guided surface of the transport unit. Compared with a ceramic conveyance roller into which no residual stress is introduced, the durability when the guided surface of the conveyance unit collides with the conveyance roller is excellent.
The transport roller of the present invention is a centrifugal ball mill operated by a revolution generated in the mill pot by placing a plurality of ceramic balls and a transport roller with an exposed outer peripheral surface in a mill pot of the planetary ball mill to operate the planetary ball mill. By applying a force and a centrifugal force accompanying rotation, the ball is made to collide with the outer peripheral surface of the transport roller, and after performing a ball mill process for introducing residual stress into the surface layer portion, it is obtained by finishing polishing Can do.

In the ball mill process, a planetary ball mill (planetary ball mill provided with a conveyance roller rotation support device in a mill pot) in which a cylindrical body that externally fits a conveyance roller is rotatably provided in the mill pot is used. It is preferable to obtain it by external fitting and operating a planetary ball mill.
The ball mill process can be performed, for example, using a planetary ball mill described in Patent Document 3 in which a cylindrical body that externally fits a transport roller is rotatably provided.

  When the ball mill process is performed in a normal mill pot not equipped with a transport roller rotation support device, the transport roller is placed in the mill pot with the outer peripheral surface exposed and the end surface and the inner surface protected from ball collision. It is necessary to put in. Further, it is necessary to adjust the rotational speed and processing time of the planetary ball mill more closely so that the transport roller does not collide with the inner wall of the mill pot.

Examples of the material of the mill pot include those made of stainless steel and provided with a lining material made of menor, alumina, zirconia, chrome steel, or silicon nitride. The lining material of the mill pot is preferably the same material as the ceramic balls to be treated.
The operating conditions of the planetary ball mill are: revolution speed: 300 rpm to 1000 rpm (more preferably 500 rpm to 700 rpm), rotation speed: 600 rpm to 2000 rpm (more preferably 1000 rpm to 1400 rpm), and rotation time: 1 hour to 8 Time or less (more preferably 3 hours or more and 5 hours or less) is preferable.

  Moreover, it is preferable that the amount of ceramic balls put into the mill pot is 50% or more and 90% or less of the closest packing amount (the amount that enters when the most densely packed into the mill pot). When the amount is less than 50% of the closest packing amount, the treatment time of the ball mill process can be shortened because the collision energy is large. However, since the movement of the ceramic balls in the pot becomes too intense, it is difficult to obtain a uniform surface. If it exceeds 90% of the closest packing amount, the range in which the ceramic balls can move in the pot becomes small, so the number of collisions increases, but the collision energy decreases and the processing takes time. By setting it to 50% or more and 90% or less of the close-packed filling amount, the number of collisions and the collision energy can be balanced and processed effectively. A more preferable range is 70% or more and 90% or less of the closest packing amount.

The finish polishing can be performed by a general method such as a ball lapping machine or a barrel process.
In addition to such a method comprising the ball mill process and the finish polishing process, a method for obtaining a “ceramics transport roller in which a compressive residual stress of 50 MPa to 1500 MPa in absolute value is introduced into the surface layer portion” is a method by shot blasting. There is.
The shot blasting process is a process in which an injection material is injected onto the surface of an object to be processed, but the environmental temperature during the treatment is preferably normal temperature, and the injection material has a hardness lower than that of silicon nitride and has a convex curved surface. And fine particles having no edge (for example, alumina particles).

  Moreover, it is preferable that the change in the surface roughness Ra of the workpiece before and after the shot blasting treatment is less than 0.02 μm. If the change in the surface roughness Ra is 0.02 μm or more, the effect of the shot blasting process may be insufficient. Further, it is preferable that the surface roughness of the object to be processed is as small as possible. Furthermore, a shot blasting process in which the change in surface roughness Ra is less than 0.02 μm is preferable because a dimensional change due to the process is small. The surface roughness may be improved by performing barrel treatment or honing treatment after the shot blast treatment.

In order for the change in the surface roughness Ra to be less than 0.02 μm, it is preferable to set the conditions for shot blasting as follows.
Average particle diameter of propellant: 50 μm or more and 100 μm or less Injection pressure: 0.1 MPa or more and 0.6 MPa or less (more preferably 0.2 MPa or more and 0.5 MPa or less)
Injection speed: 30 m / s or more and 90 m / s or less Injection amount: 200 g / min or more and 800 g / min or less If the shot blast treatment is performed under such conditions, the compressive residual stress is introduced at a more preferable value of 150 MPa or more and 1500 MPa or less. be able to.

  The present invention also includes the conveyance roller of the present invention, a rolling bearing that rotatably supports the conveyance roller with respect to an axis, and a conveyance unit that includes a guided surface that is brought into contact with the outer peripheral surface of the conveyance roller. In a vacuum transfer device that is used with a vacuum inside, the vacuum transfer device is characterized in that any one of the following three types of lubricating coating (DFO lubricating coating) is formed on the raceway surface of the rolling bearing: I will provide a.

(1) Lubricating film containing a fluoropolymer having a functional group and perfluoropolyether
(2) Lubricating film containing a functional group-containing fluoropolymer, perfluoropolyether and fluororesin
(3) A lubricating coating containing a lubricating oil mainly composed of alkylated cyclopentane or polyphenyl ether and a fluororesin

According to the vacuum transfer device of the present invention, since the DFO lubrication film is formed on the raceway surface of the rolling bearing that rotatably supports the transfer roller with respect to the shaft, it is compared with the case where fluorine oil or fluorine grease is used. Thus, the amount of gas release can be reduced while ensuring good lubrication performance, and the durability of the rolling bearing is also improved.
In the vacuum transfer device of the present invention, there are a case where the transfer roller is fitted on the rolling bearing and a case where the outer peripheral portion of the outer ring of the rolling bearing forms the transfer roller.

According to the transport roller of the present invention, the durability when the guided surface of the transport unit collides with the transport roller is excellent.
According to the vacuum transfer device of the present invention, the durability of the transfer roller is high, and high cleanliness can be secured while improving the lubrication performance of the rolling bearing.

Hereinafter, embodiments of the present invention will be described.
FIG. 1A is a front view showing a vacuum transfer device corresponding to one embodiment of the present invention, and FIG.
The vacuum transfer device includes a transfer roller 1, a rolling bearing 2, a rotary shaft 3 extending horizontally from a wall in the vacuum transfer device, and a carriage (transfer unit) 4 to which a disk medium D is attached. The transport roller 1 is supported by a rolling bearing 2 so as to be rotatable with respect to the rotary shaft 3. A rail (guide surface) 4 a is fixed to the lower portion of the carriage 4. The conveyance roller 1 guides the carriage 4 by rotating with the outer peripheral surface in contact with the rail 4a.

The transport roller 1 is made of silicon nitride (ceramic material), and a compressive residual stress of 50 MPa or more and 1500 MPa or less in absolute value is introduced into the surface layer portion of the outer peripheral surface. In addition, a DFO lubricating coating that releases less gas than fluorine grease is formed on the raceway surface of the rolling bearing 2.
Therefore, according to this vacuum transfer device, the durability when the carriage 4 rail 4a collides with the transfer rollers 1a and 1b is improved, and the amount of gas released from the lubricant of the rolling bearing 2 is small. The yield of D is high, and the cost for maintenance can be reduced.

The transport roller 1 is obtained by performing a ball mill process using a planetary ball mill having a mill pot shown in FIG. 2 and a finish polishing process.
The mill pot 40 shown in FIG. 2 can process four transport rollers 1 at the same time, and four housings 41 are equidistantly arranged on the bottom surface of the mill pot 40 along a circle concentric with the rotation circle of the mill pot 40. It is fixed. In addition, a rotating shaft 43 is attached to each housing 41 via a rolling bearing 42, and a cylindrical body 44 that externally fits the conveying roller 1 is integrated on the upper portion of the rotating shaft 43 while shifting the shaft.

By driving the planetary ball mill, the mill pot 40 revolves around an axis (not shown) while rotating as indicated by an arrow in FIG. Along with this, the cylindrical body 44 rotates relatively by the inertial force, so that the transport roller 1 fitted on the cylindrical body 44 rotates while changing its direction at random.
Therefore, when the ball 5 is inserted into the mill pot 40 and the planetary ball mill is driven, the ball 5 is given a centrifugal force accompanying the revolution generated in the mill pot 40 and a centrifugal force accompanying the rotation, so that the ball 5 is moved into the mill pot 40. And collides with the outer peripheral surface of the conveying roller 1 that rotates while changing its direction at random. As a result, compressive residual stress is introduced into the surface layer portion of the outer peripheral surface of the transport roller 1.

[First embodiment]
In this embodiment, a silicon nitride ball 5 having a surface roughness (Ra) of 0.002 μm and a diameter of H768 of 4.768 mm in the mill pot 40 of FIG. 2 is 50% by volume of the closest packing amount of the mill pot 40. The cylindrical roller 44 was fitted with a silicon nitride transport roller 1 having a surface roughness (Ra) of 0.002 μm and Hv 1500, and the planetary ball mill was operated for 7 hours under the following conditions.

Revolution speed: 500 rpm (No. 1-1), 300 rpm (No. 1-2)
Rotational speed: 1000 rpm (No. 1-1), 600 rpm (No. 1-2)
Rotation time: 7 hours (No. 1-1), 4 hours (No. 1-2)
After performing this ball mill process, the conveyance roller 1 was removed from the cylindrical body 44, and a final polishing process was performed with a ball lapping machine to remove the surface layer portion of the conveyance roller 1 with a thickness of 3 μm. The ball 5 was also subjected to a final polishing process with a ball lapping machine, and the surface layer portion was removed at a thickness of 3 μm to a diameter of 4.762 mm.

Two of the four transport rollers 1 thus obtained (No. 1-1, No. 1-2) and a transport roller 1 made of silicon nitride of Hv1500, which performs the ball mill process. The durability (No. 1-3, No. 1-4) obtained by the same method except for the above was examined using the durability test apparatus shown in FIG.
The test apparatus shown in FIG. 3 includes a cam 61 having a step 61a, a rotating shaft 62 of the cam 61, a linear motion device 63, and a spring 64. The spring 64 has an upper end fixed to a member extending vertically from the wall surface, and a linear motion device 63 is fixed to the lower end. The conveying roller 1 is attached to the rotating shaft 3 extending vertically from the linear motion device 63 via the rolling bearing 2, and the outer peripheral surface of the conveying roller 1 is always in contact with the peripheral surface of the cam 61 to drive the rotating shaft 62. As a result, the cam 61 is rotated.

As the cam 61 rotates in the direction of the arrow shown in FIG. 3A, the transport roller 1 rotates while being pushed down from the state of FIG. 3A by the cam 61, and the position of the step 61a of the cam 61 passes. Sometimes an impact is applied to the outer peripheral surface of the transport roller 1.
Using this test apparatus, the conveyance roller 1 is rotated at a rotation speed of 150 times per minute in an environment of vacuum and room temperature, and the surface roughness (maximum) of the running trace is reached at 5 million times and 10 million times. Height) was measured. The results are shown graphically in FIG.

The surface roughness after finish polishing was measured using a plate-shaped test piece made of silicon nitride of Hv1500, 10 mm × 10 mm × thickness 5 mm. That is, in No. 1-1 and 1-2, what performed the ball mill process and the finish grinding | polishing process with the same method as the above-mentioned No. 1-1 and 1-2 with respect to the surface of this test piece was used. . In Nos. 1-3 and 1-4, this test piece was used as it was.
Further, a test specimen for measuring Vickers hardness made of silicon nitride of Hv 1500 was subjected to a ball mill process and a finish polishing process by the same method as Nos. 1-1 and 1-2 described above. When the thickness was measured, it was 1590 for No. 1-1 and 1570 for No. 1-2. Nos. 1-3 and 1-4 remain 1500 because they are not processed.

  Further, when the fracture toughness value was measured using the test pieces subjected to the ball milling process and the finish polishing process of No. 1-1 to 1-4, No. 1-1 was 18 MPa · √m, No. 1- 2 was 13 MPa · √m, and Nos. 1-3 and 1-4 were 6 MPa · √m. The fracture toughness value was obtained from the measured values of the indentation and cracks generated by setting the indentation condition of the diamond indenter to 196 N for 20 seconds.

Further, when the fracture toughness value was measured at each depth position from the surface of the test piece, the position at which the fracture toughness value converges to a constant value (toughness depth) was No. 1-1 at 40 μm, No. 1- 2 and 30 μm, and the fracture toughness values of Nos. 1-3 and 1-4 were constant in the depth direction.
Moreover, when the compressive residual stress of the balls 5 of No. 1-1 to 1-4 was measured by X-ray diffraction, the absolute value of the compressive residual stress was 1200 MPa for No. 1-1 and 300 MPa for No. 1-2. No. 1-3 and 1-4 were 20 MPa. It is estimated that the compressive residual stress of the conveying roller 1 is also the same as that of the ball 5.
These results are summarized in Table 1 below.

  From the graph of FIG. 4, the transport rollers 1 of No. 1-1 and 1-2 corresponding to the embodiment of the present invention had a surface roughness of 5 to 6 μm after running 10 million times. On the other hand, the No. 1-3 and 1-4 conveyance rollers 1 corresponding to the comparative example are as large as about 9 μm, and the No. 1-1 and 1-2 conveyance rollers 1 are excellent in wear resistance. I understand.

[Second Embodiment]
First, a shot blasting process using alumina particles (Hv1300) having an average particle size of 100 μm as a propellant was performed on a test piece (width 10 mm, length 10 mm, thickness 5 mm) made of silicon nitride (Hv1500), and thereby The degree of change in toughness, increased hardness, and surface roughness Ra was evaluated.
Table 2 shows shot blasting conditions and evaluation results. The fracture toughness value was measured by the method defined in “JIS R 1607”.

Further, when the half width of the peak by X-ray diffraction of the silicon nitride test piece was measured and the relationship with the fracture toughness value was examined, the graph of FIG. 5 was obtained. The X-ray diffraction conditions are CrKα ray, voltage 40 kV, current 40 mA, no-strain diffraction angle 2θ ₀ = 125.40 ° (β-Si ₃ N ₄ (411)), collimator lens diameter 1 mm, and measurement time 120 seconds. .
Since the absolute value of the compressive residual stress is proportional to the half width of the X-ray diffraction peak, it can be seen from the graph of FIG. 5 that the higher the fracture toughness value, the greater the absolute value of the compressive residual stress.

Nos. 2-1 and 2-2 are subjected to shot blasting, and the compressive residual stress is in the range of 50 MPa to 1500 MPa in absolute value. As can be seen from the numerical values of No. 2-3 that have not been subjected to shot blasting, the Vickers hardness and fracture toughness are increased by shot blasting.
No. 2-4 is shot blasted, but the compressive residual stress is less than 50 MPa in absolute value, so the effect of shot blasting does not appear, and the Vickers hardness and fracture toughness values change. I did not. In No. 2-5, although the shot blast treatment was performed, the compressive residual stress exceeded 1500 MPa in absolute value, so that a large crack was generated when the fracture toughness value was measured, and the test piece was damaged. .

Next, the durability of the transport roller 1 shown in FIG. 1 formed of Hv1500 silicon nitride and the one processed in the same manner as Nos. 2-1, 2-2, 2-4. The durability was examined using the durability test apparatus of FIG. 3 under the same conditions as in the first example. The results are shown graphically in FIG.
From the graph of FIG. 6, the transport rollers 1 of No. 2-1 and 2-2 corresponding to the embodiment of the present invention had a surface roughness of 6 to 7 μm after running 10 million times. On the other hand, the No. 2-3 and 2-4 conveyance rollers 1 corresponding to the comparative example are as large as about 9 μm, and the No. 2-1 and 2-2 conveyance rollers 1 are excellent in wear resistance. I understand.

[About lubrication coating (fluorine oil coating) of rolling bearings]
The gas releasing property of the lubricant was examined using the test apparatus shown in FIG. This apparatus includes a first vacuum tank 72 and a second vacuum tank 73 that are divided into left and right via an orifice 71, a turbo pump 74, an auxiliary pump 75, a heater 76, and vacuums provided in the vacuum tanks 72 and 73. It consists of 77 and 78 in total. The heater 76 heats a table 79 on which the rolling bearing 2 provided in the first vacuum chamber 72 is placed.

The rolling bearing 2 installed in the first vacuum chamber 72 is heated to 100 ° C. by the heater 76, and the pressure P2 of the second vacuum chamber 73 is 8 × 10 ⁻⁶ Pa by the turbo pump 74 and the auxiliary pump 75. Like that. The gas released from the rolling bearing 2 passes through the orifice 71 and moves to the second vacuum chamber 73. The amount of gas that has passed through the orifice 71 from the pressure P1 measured by the vacuum gauge 77 of the first vacuum chamber 72 and the pressure P2 measured by the vacuum gauge 78 of the second vacuum chamber 73 by the following equation (1) Q can be calculated. C is the conductance of the orifice 71.
Q = C (P1-P2) (1)

Using this apparatus, a fluorine oil coating is applied to the raceway surface of the rolling bearing 2 at 0.5 g / m ² , 1.0 g / m ² , 1.5 g / m ² , 2.0 g / m ² , 3. The amount of gas released at 100 ° C. was measured when it was formed to have respective amounts of 0 g / m ² , 5.0 g / m ² , 10.0 g / m ² , and 15.0 g / m ² . The result is shown by a curve A in the graph of FIG. A straight line B in the graph of FIG. 8 shows the result when the release gas is measured using the apparatus of FIG. 7 by filling the bearing space of the rolling bearing 2 with fluorine grease.

From this graph, when the fluorine oil coating amount is 12 g / m ² or more, the amount of gas released from the fluorine oil coating is larger than the amount of gas released in the case of fluorine grease. Therefore, the fluorine oil coating amount is preferably 10 g / m ² or less.
Further, a rotation test was performed by forming 0.5 g / m ² , 1.0 g / m ² , and 1.5 g / m ² of a fluorine oil film on the raceway surface of the rolling bearing 2. The test conditions were bearing orientation: horizontal axis, rotational speed: 150 min ⁻¹ , temperature: 100 ° C., pressure environment: vacuum, and the total number of revolutions when the bearing torque exceeded twice the initial value was defined as the life. If the bearing torque does not exceed twice the initial value even if the total rotational speed exceeds 1.0 × 10 ⁷ , the test was terminated at that time.

The result is also indicated by “Δ” in FIG. In FIG. 8, the arrow means test termination, and it can be seen that good durability is obtained when the fluorine oil coating amount is 1.0 g / m ² or more.
From these results, the fluorine oil coating amount is preferably 1.0 g / m ² or more and 10 g / m ² or less.

[About lubrication coating (DFO coating) of rolling bearings]
When a 2.0 g / m ² DFO coating was formed on the raceway surface of the rolling bearing 2 and the amount of released gas at 100 ° C. was measured by the same method as described above, it was found to be 2.1 × 10 ⁻⁸ Pa with PFPE base oil. · m is ³ / s, MAC base oil was ^{1.3 × 10 -8 Pa · m 3} / s, 3.0 × 10 -8 in the case of forming a fluorine oil coating 2.0 g / m ² The amount of released gas was less than Pa · m ³ / s.

Further, each of these rolling bearings was attached to a rotary testing machine with a vertical axis, and the life was examined with the direction of rotation reversed every time. The test conditions were rotational speed: 150 min ⁻¹ , temperature: 100 ° C., pressure environment: vacuum, and the total number of cycles when the bearing torque exceeded twice the initial value was defined as the life. If the bearing torque did not exceed twice the initial value even when the total number of cycles exceeded 5 × 10 ⁶ , the test was terminated at that point.
The result is shown in the graph of FIG. From this result, it can be seen that the DFO film as the lubricating film of the rolling bearing is superior in durability compared to the case where the fluorine oil film is used.

[Conveying roller shape]
As shown in FIGS. 10 and 11, the outer peripheral surface of the transport roller 1 is formed in a convex shape and the rail 4 a is formed in a concave shape, so that the rail 4 a is not easily detached from the transport roller 1. In the example of FIG. 10, the curvature of the radius of the convex part 11 of the conveyance roller 1 is made smaller than the curvature of the radius of the concave part 4b of the rail 4a. In the example of FIG. 11, the convex part 11 of the conveyance roller 1 is rounded, and the concave part 4b of the rail 4a is V-shaped.

  In this embodiment, the conveyance roller 1 is separate from the rolling bearing 2 and the conveyance roller 1 is externally fitted to the outer ring of the rolling bearing. However, as shown in FIG. In some cases, the outer ring 21 of the bearing 2 is used as a conveying roller. In this case, a compressive residual stress of 50 MPa or more and 1500 MPa or less is introduced into the surface layer portion of the outer peripheral surface of the outer ring 21.

It is sectional drawing which shows the vacuum conveyance apparatus corresponded to one Embodiment of this invention. It is sectional drawing (a) which shows the mill pot of the planetary ball mill used at the ball mill process of a conveyance roller, and its AA sectional drawing (b). It is the schematic block diagram (a) which shows the testing apparatus used in order to investigate durability, and its BB sectional drawing (b). It is a graph which shows the result of the test done in the 1st example by the relation between the total number of rotations of a conveyance roller, and the surface roughness (maximum height) of a run track. It is a graph which shows the relationship between the half width of the peak by X-ray diffraction, and a fracture toughness value. It is a graph which shows the result of the test done in the 2nd example by the relation between the total number of rotations of a conveyance roller, and the surface roughness (maximum height) of a run track. It is a schematic block diagram which shows the test apparatus which investigates the gas release property from the lubricant of a rolling bearing. It is a graph which shows the relationship between the coating amount of the fluorine oil formed in the raceway surface of a rolling bearing, the amount of gas discharge | released from a rolling bearing, and the lifetime of a rolling bearing. It is a graph which shows the relationship between the test temperature and lifetime when the lubricating film formed in the raceway surface of a rolling bearing differs. It is sectional drawing which shows the 1st example which formed the outer peripheral surface of the conveyance roller in convex shape, and formed the rail in concave shape. It is sectional drawing which shows the 2nd example which formed the outer peripheral surface of the conveyance roller in convex shape, and formed the rail in concave shape. It is sectional drawing which shows the example which uses the outer ring | wheel of a rolling bearing as a conveyance roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conveyance roller 11 Convex part of conveyance roller 2 Rolling bearing 3 Rotating shaft D Disk media 4 Carriage (conveyance part)
4a Rail (guided surface)
4b Rail recess 40 Mill pot 41 Housing 42 Rolling bearing 43 Rotating shaft 44 Cylindrical body to which the conveying roller is fitted 5 Ball 61a Stage 61 Cam 62 Rotating shaft 63 Cam linear motion device 64 Spring 71 Orifice 72 First vacuum chamber 73 First Vacuum tank 2 74 Turbo pump 75 Auxiliary pump 76 Heater 77, 78 Vacuum gauge 79 Stand for rolling bearing

Claims (4)

In the transport roller for guiding the transport unit by rotating the outer peripheral surface in contact with the guided surface of the transport unit,
A conveyance roller, which is made of a ceramic material and has a compressive residual stress of 50 MPa to 1500 MPa as an absolute value introduced into a surface layer portion of the outer peripheral surface.   A planetary ball mill is operated by placing a plurality of ceramic balls and a conveying roller with an exposed outer peripheral surface in a mill pot of a planetary ball mill. 2. After the ball mill step of causing the ball to collide with the outer peripheral surface of the transport roller and introducing residual stress to the surface layer portion by applying the above, a finish polishing process is performed. The conveyance roller as described.   The ball mill process according to claim 2 is performed by using a planetary ball mill in which a cylindrical body that externally fits a transport roller is rotatably provided in a mill pot, and by operating the planetary ball mill by externally fitting the transport roller to the cylindrical body. The conveyance roller according to claim 1 obtained by the above. The conveyance provided with the conveyance roller of any one of Claims 1-3, the rolling bearing which supports the said conveyance roller rotatably with respect to an axis | shaft, and the to-be-guided surface which contacts the outer peripheral surface of the said conveyance roller. A vacuum transfer device that is used with a vacuum inside,
Any one of the following three types of lubricating coatings is formed on the raceway surface of the rolling bearing.
(1) Lubricating film containing a fluoropolymer having a functional group and perfluoropolyether
(2) Lubricating film containing a functional group-containing fluoropolymer, perfluoropolyether and fluororesin
(3) A lubricating coating containing a lubricating oil mainly composed of alkylated cyclopentane or polyphenyl ether and a fluororesin

Images