JP2003139139A - Rolling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling device suitably used even under environment demanding corrosion resistance, non-magnetism, and conductivity. SOLUTION: A rolling body 13 disposed rollably between an outer ring 11 and an inner ring 12 is formed of α+β type titanium alloy or β type titanium alloy, and surface hardness of the rolling body 13 is set to Hv400 or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling device such as a rolling bearing, a ball screw, a linear motion guide device, etc., and in particular, it is used in a semiconductor manufacturing device, a liquid crystal manufacturing device, a chemical fiber manufacturing device, a food machine, etc. The present invention relates to a rolling device suitable for use in an environment in which corrosion resistance to salt water, chemicals, etc. is required, or in an environment in which non-magnetism is required such as a measuring device using X-rays or electron beams.

[0002]

2. Description of the Related Art A rolling device such as a rolling bearing is generally constructed by arranging a large number of rolling elements between an outer member and an inner member, and one of the outer member and the inner member is arranged. The rolling element rolls between the outer member and the inner member by rotating or linearly moving. The rolling elements of such rolling devices are conventionally formed of steel materials such as high carbon chrome bearing steel and case hardening steel, but in recent years, in order to improve corrosion resistance against water and salt water, stainless steel is used. Rolling devices have also appeared. However, there are various environments in which the rolling device is used, and corrosion resistance may be insufficient even if it is made of stainless steel. For example, in a wafer cleaning apparatus that cleans semiconductor wafers, a mixed solution of ultrapure water mixed with ammonia water and hydrogen peroxide water is used as a cleaning liquid. When the rolling device of is used, corrosion of the rolling elements progresses,
The metal ions eluted by the corrosion may become impurities and contaminate the wafer.

Further, in a measuring device and an analyzing device using X-rays or electron beams, the accuracy of measurement is lowered when the peripheral magnetic field is disturbed. Therefore, a rolling device used in such a device is, for example, an inner member. In order to reduce the influence of the rotation on the peripheral magnetic field, the outer member and the inner member are often formed of non-magnetic stainless steel. However, the non-permeability of non-magnetic stainless steel is about 1.04 to 1.002, which is unsuitable for use in an environment where more complete non-magnetism is required.

Therefore, the outer member and the inner member are made of a metal material other than steel material (for example, titanium alloy, beryllium copper alloy).
As a rolling device formed by the method described in JP-A-11-223221.
There is one disclosed in Japanese Laid-Open Patent Publication No. 5-79042. However, in the rolling device disclosed in the above publication, the rolling elements are formed of ceramics such as silicon nitride, and the surface hardness of the ceramics is Hv 1300 or more. Therefore, for example, an outer member made of titanium alloy or The wear of the inner member was sometimes accelerated. further,
Since the ceramic rolling element does not have conductivity, it is unsuitable for use in an environment where both non-magnetism and conductivity are required, such as a measuring device using an electron beam.

[0005]

As described above, in the conventional rolling device, since the rolling elements are made of ceramics such as silicon nitride, the outer member made of, for example, titanium alloy or beryllium copper alloy, There is a problem that the wear of the inner member is promoted. Further, since the ceramic rolling element has no conductivity, it is unsuitable for use in an environment where both non-magnetic property and conductivity are required, such as a measuring device using an electron beam.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a rolling device which can be suitably used even in an environment where corrosion resistance, nonmagnetic property or conductivity is required. To provide.

[0007]

In order to achieve the above object, the invention of claim 1 provides a rolling device in which a rolling element is arranged between an outer member and an inner member. The rolling element is formed of an α + β type titanium alloy or a β type titanium alloy, and the surface hardness of the rolling element is Hv 400 or more. According to a second aspect of the present invention, in the rolling device according to the first aspect, the surface hardness of the rolling element is Hv400.
It is characterized in that the Hv is less than 600.

According to a third aspect of the present invention, in the rolling device according to the first aspect, the surface hardness of the rolling element is Hv 450 or more and Hv or more.
It is characterized in that it is less than v600. According to a fourth aspect of the present invention, in the rolling device according to the first aspect, the outer member and the inner member are formed of a non-magnetic metal material having a non-permeability of 1.001 or less.

[0009]

In general, rolling devices used in special environments where non-magnetism and corrosion resistance are required have precipitation-hardening type high corrosion-resistant stainless steel, non-magnetic stainless steel, beryllium copper and titanium for outer and inner members. Many are made of special metal materials such as alloys (surface hardness: about Hv350 to 550), and rolling elements are made of ceramics (surface hardness: Hv1300 or more). In the rolling device, a high contact pressure is generated at the contact point between the outer member and the rolling element and between the inner member and the rolling element, and therefore the rolling element is required to have strength capable of withstanding the high contact pressure. To meet such requirements, the rolling element of the rolling device according to the present invention is formed of a β-type titanium alloy or an α + β-type titanium alloy whose hardness is improved by heat treatment, and has a surface hardness of Hv 400 or more. ing. Here, when the hardness is less than Hv400, the wear resistance and load resistance are deteriorated due to insufficient hardness, but the surface hardness of the titanium alloy rolling element is Hv400.
In the above cases, the wear resistance is improved. Preferably, the surface hardness is Hv 450 or higher in order to further improve wear resistance.

However, the hardness of the rolling elements is Hv600.
If it becomes above, since the hardness of the above-mentioned outer member and inner member which are made of a special metal material is about Hv350-550, the surface hardness of the rolling element is larger than the surface hardness of the outer member and the inner member. Become. Therefore, the rolling elements are less likely to be worn, but the outer member and the inner member are likely to be preferentially worn. Therefore, the rolling element of the rolling device according to the present invention has a surface hardness of Hv600 or less. Thereby, in the rolling device of the present invention, the difference between the surface hardness of the rolling element and the surface hardness of the outer member and the inner member becomes small,
The wear of the outer member and the inner member is not unidirectionally promoted.

The heat treatment of the α + β type titanium alloy or the β type titanium alloy is performed by the solution treatment and the aging treatment described below. Solution treatment refers to titanium alloy α / β
This is a treatment in which the metal structure is made into a uniform β phase or a structure in which a small amount of α phase remains in the β phase by maintaining the temperature just above or below the transformation point and quenching from that temperature.
On the other hand, the aging treatment is a titanium alloy in which the solution-treated titanium alloy is heated to a temperature of about 350 ° C. to 600 ° C. and held for a predetermined time to finely precipitate the α phase from the β phase. Is a process for improving the hardness of the.

In order to further improve wear resistance and slidability of the rolling device, titanium alloy rolling elements and outer and inner members are oxidized or treated with a lubricating coating such as a fluorine oil baking film. It is possible to further improve wear resistance and slidability by applying. The term "oxidation treatment" as used herein refers to, for example, a heat oxidation treatment or an anodization treatment, and by applying such an oxidation treatment to the surface of the rolling element, the outer member or the inner member, a rutile type or anatase having a thickness of 20 nm or more. Formed titanium oxide.

As the titanium alloy constituting the rolling element, it is preferable to use an α + β type titanium alloy or a β type (including near β type) titanium alloy which can obtain high hardness by solution treatment and aging treatment. Examples of the α + β type titanium alloy include Ti-6Al-4V, and examples of the β type titanium alloy include Ti-22V-4Al and Ti-15V-3C.
r-3Sn-3Al, Ti-15Mo-5Zr-3A
1, Ti-15Mo-5Zr and the like.

The Young's modulus of ceramics is about 250.
The Young's modulus of titanium alloy is 10 to 450 GPa.
It shows a low value of about 0 to 200 GPa. This is because the titanium alloy rolling element has a larger contact area with the outer member and the inner member than the ceramic rolling element, and the local surface pressure when the load or impact is applied to the rolling device. It means decreasing. Therefore, the rolling device according to the present invention is
Since the contact surface pressure between the rolling element and the inner member and outer member decreases when a load or impact is applied to the outer member and inner member, the contact point between the rolling element and the inner member and outer member It is possible to suppress the generation of indentations and alleviate rolling fatigue.

Further, since the titanium alloy rolling element of the rolling device according to the present invention has a relative magnetic permeability of 1.001 or less, the outer member and the inner member are made of a non-magnetic material such as titanium alloy or non-magnetic stainless steel. By being formed of a metal material, it can be suitably used even in an environment where non-magnetism is required. In this case, by forming the outer member and the inner member from a titanium alloy having a relative magnetic permeability of 1.001 or less, the outer member and the inner member can be suitably used even in an environment where a high level of non-magnetism is required.

For example, when the rolling device according to the present invention is used in a magnetic field environment such as a semiconductor manufacturing device, a liquid crystal manufacturing device, a medical device, a measuring device using an X-ray or an electron beam, it is rolled by a magnetic field. Since the moving device is not pulled and the movement of the rolling device is not unstable, and the peripheral magnetic field is not disturbed by the rotation of the outer member or the inner member, it can be preferably used. Further, even when used near an electron beam or the like, the electron beam is not disturbed by the rotation of the outer member or the inner member, so that the accuracy of the measuring device using the electron beam is not deteriorated.

In particular, a device using an electron beam such as an electron microscope is often required to have non-magnetism and conductivity at the same time. If the rolling element of the rolling device is made of an insulating material such as ceramics, a charge-up phenomenon occurs, and the accuracy of the measuring device using the electron beam is reduced. In the rolling device of the present invention, since the rolling elements are formed of a titanium alloy having conductivity, the rolling member is formed by forming the outer member and the inner member of a titanium alloy having non-magnetism and conductivity. Since the entire device has non-magnetism and conductivity, it can be preferably used in a device using an electron beam.

In the rolling device according to the present invention, the rolling element is α +
Since it is formed from a β-type titanium alloy or a β-type titanium alloy, it can be suitably used in a measuring device that uses an electron beam, and by forming the outer member and the inner member from a titanium alloy, It can be suitably used depending on the measuring device used. Further, the titanium alloy rolling element of the rolling device according to the present invention has extremely excellent corrosion resistance. Therefore, even if a chemical such as an acid or an alkali or a corrosive gas is used in applications where corrosion resistance is required, such as semiconductor manufacturing equipment, liquid crystal manufacturing equipment, chemical fiber manufacturing equipment, etc. Since it is less likely to be corroded as compared with the moving body, the rolling device needs to be replaced less frequently, and can be suitably used.

In the rolling device according to the present invention, the cage for holding the titanium alloy rolling element is not particularly limited in material as long as it has a usable temperature range, but is preferably polyamide, fluororesin or the like. Resin, brass, austenitic stainless steel such as SUS304 can be used as a cage material, and in applications where grease cannot be used, it is preferable to use a fluororesin having self-lubricating property as a cage material. The rolling device according to the present invention may have a structure with or without a seal. The material of the seal is not particularly limited as long as it is within the usable temperature range. For example, a rubber seal such as nitrile rubber can be used.
Austenitic stainless steel seals such as 304 and industrial pure titanium seals can be preferably used. Also,
The grease sealed inside the rolling device is not particularly limited, but when used in vacuum, it is preferable to use fluorine grease for vacuum.

The rolling device according to the present invention is a general term for a rolling bearing, a linear motion guide device, a ball screw, etc. The inner member means an inner ring when the rolling device is a rolling bearing, and also a linear motion device. In the case of a guide device, it means a guide rail, and in the case of a ball screw, it means a screw shaft. The outer member means an outer ring when the rolling device is a rolling bearing, a slider when the rolling device is a linear motion guide device, and a nut when the ball rolling device is a ball screw.

As the rolling bearing, a deep groove ball bearing,
There are various types such as angular contact ball bearings, self-aligning ball bearings, cylindrical roller bearings, tapered roller bearings, self-aligning roller bearings, needle roller bearings, etc. Can be suitably used by appropriately selecting.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Before explaining the embodiments of the present invention,
The structure of the rolling bearing will be described with reference to FIG. In FIG. 1, a rolling bearing 10 is an outer ring 1 as an outer member.
1, an inner ring 12 as an inner member provided inside the outer ring 11, and a large number of spherical rolling elements 13 rotatably arranged between the inner ring 12 and the outer ring 11. Cage,
A rolling element 13 is provided between the outer ring 11 and the inner ring 12
Also, a cage 14 that holds the inner ring 12 at substantially constant intervals in the circumferential direction is incorporated.

Table 1 shows examples and comparative examples of the present invention having such a configuration.

[0024]

[Table 1]

In Table 1, in Example 1, the outer ring and the inner ring (hereinafter referred to as bearing rings) are SUS630, the rolling elements (surface hardness: Hv440) are Ti-6Al-4V, and the cage is a rolling bearing made of fluororesin. In Example 2, the bearing ring is SU
S630, rolling element (surface hardness: Hv498) is Ti-1
5Mo-5Zr-3Al, cage is a rolling bearing made of fluororesin, Example 3 is a rolling bearing in which the bearing ring is SUS630, the rolling element (surface hardness: Hv443) is Ti-22V-4Al, and the cage is made of fluororesin. In Example 4, the bearing ring is YHD50, and the rolling element (surface hardness: Hv438) is T
i-6Al-4V, the cage is a rolling bearing made of fluorocarbon resin, Example 5 is a bearing ring YHD50, the rolling element (surface hardness: Hv495) is Ti-15Mo-5Zr-3Al,
The cage is a rolling bearing made of fluororesin.

In Example 6, the bearing ring is YHD50, and the rolling element (surface hardness: Hv448) is Ti-22V-4A.
l, Rolling bearing whose cage is made of fluororesin, Example 7
Has a bearing ring of Ti-6Al-4V and rolling elements (surface hardness: H
v497) is Ti-15Mo-5Zr-3Al, and the cage is a rolling bearing made of fluororesin. In Example 8, the bearing ring and rolling elements (surface hardness: Hv437) are Ti-6Al-4.
V, rolling bearing whose cage is made of fluororesin, Example 9
Indicates that the bearing ring and rolling elements (surface hardness: Hv493) are Ti-
15Mo-5Zr-3Al, the cage is a rolling bearing made of fluororesin, and Example 10 is a rolling bearing in which the bearing ring and rolling elements (surface hardness: Hv447) are made of Ti-22V-4Al, and the cage is made of fluororesin. .

On the other hand, in Comparative Examples 1 and 2, the bearing ring is T
i-6Al-4V, the rolling elements are silicon nitride ceramics,
Cage is a rolling bearing made of fluororesin, Comparative example 3 is a bearing ring made of Ti-15Mo-5Zr-3Al, rolling elements are silicon nitride ceramics, cage is a rolling bearing made of fluororesin, and Comparative example 4 is a bearing ring. Ti-15Mo-5Zr-
3Al, the rolling element is SUS440C, the cage is a rolling bearing made of fluororesin, Comparative Examples 5 and 6 are rolling bearings made of Ti-22V-4Al, the rolling elements are SUS440C, and the cage is a fluororesin rolling bearing. .

In Table 1, Ti-6Al-4V, Ti
-15Mo-5Zr-3Al, Ti-22V-4Al
Has undergone solution treatment and aging treatment to improve hardness, and Ti-6Al-4V has a hardness of 950 to 1000.
After being kept at a temperature of ° C for about 1 hour, the solution treatment is performed by gas cooling. On the other hand, Ti-15Mo
-5Zr-3Al and Ti-22V-4Al are 750-
After being kept at a temperature of 850 ° C. for about 1 hour, the solution treatment is performed by gas cooling. Also, Ti-6
Al-4V, Ti-15Mo-5Zr-3Al and Ti
After the solution treatment, -22V-4Al is kept at a temperature of 400 to 550 ° C. for about 4 to 60 hours, and then cooled in a furnace to be aged.

The present inventor conducted the following test in order to confirm whether or not it can be suitably used in an environment where corrosion resistance, non-magnetic property or conductivity is required. [Corrosion Resistance Judgment Test] A test bearing similar to that shown in Table 1 was immersed in 0.1 N hydrochloric acid for about 20 hours, and the weight change of the test bearing before and after the test was measured. Based on the weight before the test, those with a weight reduction rate of 1% or more are evaluated as non-corrosion resistance (X in the table), and those with a weight reduction rate of less than 1% are evaluated as pass corrosion resistance (○ in the table). did. [Non-Magnetic Judgment Test] Test bearings similar to those shown in Table 1 were prepared, and changes in magnetic flux density around the bearings were measured by the test apparatus shown in FIG. Specifically, the test bearing 20 is attached to the rotary shaft 21, the permanent magnet 22 is installed around the test bearing 20, the rotary shaft 21 is rotated at a speed of 100 rpm, and the magnetic flux density at that time is measured by the Tesler meter 23. did. And, when the maximum magnetic flux density change of the magnetic flux density obtained by the Tessler meter 23 is 0.1 mT or more, the magnetic flux density change is: Yes (in the table), and when the maximum magnetic flux density change is less than 0.1 mT, the magnetic flux density change is: No. (○ in the table) was evaluated. [Conductivity Judgment Test] Using an electric resistance measuring device, the terminals of the electric resistance measuring device are applied to the inner ring and the outer ring of the manufactured test bearing, the electric resistance between the inner ring and the outer ring is measured, and the resistance value is 10Ω.
The above-mentioned items were evaluated as conductivity failure (x in the table), and those of less than 10Ω were evaluated as conductivity pass (◯ in the table).

Table 1 shows the results of the above corrosion resistance judgment test, nonmagnetic judgment test and conductivity judgment test. From the test results of Table 1, in Examples 1 to 3 of the present invention, the rolling elements are made of titanium alloy, and the inner ring and the outer ring are made of SUS630 which is high corrosion-resistant stainless steel, so that they are excellent in corrosion resistance and conductivity. Recognize. In Examples 4 to 6 of the present invention, the rolling elements are made of titanium alloy, and the inner ring and the outer ring are made of non-magnetic stainless steel such as YHD50 (manufactured by Hitachi Metals, Ltd.), so that they are excellent in non-magnetic property and conductivity. I understand.

In Examples 7 to 10 of the present invention, since the rolling elements are made of titanium alloy and the inner ring and the outer ring are made of titanium alloy, it can be seen that they are excellent in corrosion resistance, non-magnetism and conductivity.
Although not shown in the table, the weight change after the corrosion resistance determination test is substantially 0, and it can be suitably used even in applications requiring high corrosion resistance. In addition, in Examples 7 to 10, the races and rolling elements were made of titanium alloy having a relative magnetic permeability of 1.001 or less, and thus had a very high level of non-magnetism.
Although not shown in the table, the change in magnetic flux density in the non-magnetic judgment test is substantially 0, and it can be suitably used even in applications requiring a high level of non-magnetic property. Further, it has conductivity between the inner ring and the outer ring. Therefore, it can be preferably used in applications such as a device using an electron beam that requires high level non-magnetism as well as conductivity. [Abrasion determination test] In order to investigate the relationship between the hardness of the rolling element surface and the wear resistance, the following test was performed.

As the rolling elements, titanium alloy rolling elements having different surface hardness were used. The surface hardness was adjusted according to the type of titanium alloy and the aging treatment conditions. The inner ring, outer ring and cage are all common except the rolling elements, and the inner ring and outer ring are SUS
440C, and a cage made of fluororesin. A rolling test of the rolling bearing was performed under the conditions described below, and the weight change of the rolling elements before and after the test was measured.

Radial load: 5 kg Rotational speed: 500 rpm Test time: 1 hour Lubrication: No lubrication Table 2 shows examples 11 to 16 of the present invention and comparative examples 11 to 1
3 shows the rolling element material, the rolling element surface hardness, and the weight change ratio of the rolling elements before and after the test. The weight change ratio was expressed with the mass of the weight change of the rolling element in Comparative Example 12 being 1.0.

[0034]

[Table 2]

FIG. 3 shows the relationship between the surface hardness of rolling elements and the weight change ratio due to wear shown in Table 2. As is clear from FIG. 3, when the rolling element surface hardness is Hv 400 or more, the wear resistance is improved. In particular, when the Hv is 450 or more, the wear amount becomes 1/5 or less of that of Comparative Example 1, and it is understood that the wear resistance is excellent. From the above, the rolling element
Formed from + β type titanium alloy or β type titanium alloy,
And the surface hardness of the rolling element is Hv 400 or more, preferably Hv
v400 or more and less than Hv600, more preferably Hv45
When it is 0 or more and less than Hv600, the difference in the surface hardness between the race and the rolling element does not become large unlike the case where the rolling elements are made of ceramics. Can be suppressed. Further, since the corrosion resistance is improved as compared with the rolling element made of stainless steel, it can be suitably used even in an environment with strong corrosiveness. Further, by forming the bearing ring with a non-magnetic metal material having a relative magnetic permeability of 1.001 or less, it can be suitably used even in an environment where non-magnetic property and conductivity are required, and the bearing ring is formed with a titanium alloy. As a result, it can be suitably used even in an environment where high corrosion resistance, non-magnetism and conductivity are required.

In the above-mentioned embodiment, the cage made of fluororesin is used as the cage for holding the rolling elements in the circumferential direction of the bearing ring at substantially constant intervals, but it is not always necessary to use the cage made of fluororesin. The material of the cage does not matter as long as it can withstand the operating temperature. Further, in the above-mentioned embodiments, Ti-6Al-4V and Ti-15Mo are used as the rolling element materials.
Although -5Zr-3Al and Ti-22V-4Al have been exemplified, a titanium alloy having a composition other than those described above may be used as long as it is a titanium alloy having a surface hardness of Hv400 or higher. Furthermore, although the rolling element of the ball bearing is targeted in the above-mentioned embodiment, the rolling element in the present invention exhibits excellent effects in corrosion resistance, non-magnetic property and conductivity, and is not limited to this. Can also be preferably used. That is, it can be suitably used for rollers of roller bearings, ballscrews and balls of linear guides.

[0037]

As described above, according to the present invention,
It is possible to provide a rolling device that can be suitably used even in an environment where corrosion resistance, non-magnetism, or conductivity is required.

[Brief description of drawings]

FIG. 1 is a sectional view of a rolling bearing.

FIG. 2 is a diagram showing a test apparatus used for a magnetic flux density change measurement test.

FIG. 3 is a diagram showing the relationship between the surface hardness of rolling elements and the weight change ratio of rolling elements before and after the rotation test.

[Explanation of symbols]

11 outer ring 12 inner ring 13 rolling elements 14 cage 15 seals 20 Test bearing 21 rotation axis 22 Permanent magnet 23 Terrace meter

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Claims (4)

[Claims] 1. A rolling device configured by arranging a rolling element between an outer member and an inner member, wherein the rolling element is formed from an α + β type titanium alloy or a β type titanium alloy, and the rolling element is formed. Surface hardness of moving body is Hv400
A rolling device characterized by the above. 2. The rolling device according to claim 1, wherein the surface hardness of the rolling element is Hv400 or more and less than Hv600. 3. The rolling device according to claim 1, wherein the surface hardness of the rolling element is Hv 450 or more and less than Hv 600. 4. The rolling device according to claim 1, wherein the outer member and the inner member are made of a non-magnetic metal material having a non-permeability of 1.001 or less.