JP2003231932A - Rolling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance a nonmagnetic level of an inner ring and an outer ring made of a titanium alloy. <P>SOLUTION: This rolling device is characterized by employing a titanium alloy which is a β type or a (α+β) type of an alloy and has 0.3 or less of a total content of magnetic elements shown in the following expression (1): content of magnetic elements=[Fe]+0.8[Co]+0.3[Ni]...(1) (where [M] represents a percentage of an element M (mass%) in the titanium alloy). <P>COPYRIGHT: (C)2003,JPO

Description

Description: 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, and a linear guide. In particular, the present invention relates to a rolling device suitable for applications requiring non-magnetism, such as a processing device or a measuring device using an electron beam or a magnetic field. 2. Description of the Related Art In recent years, processing devices and measurement devices utilizing an electron beam or a magnetic field have been used as semiconductor device manufacturing apparatuses, liquid crystal manufacturing apparatuses, medical equipment and the like. In a device using a magnetic field, even if the degree of magnetization of the rolling device is small, the magnetic field may be disturbed by the operation of the rolling device, and measurement accuracy or operation accuracy may be reduced. Therefore, in such an application, by using a nonmagnetic stainless steel rolling device having a relative magnetic permeability of about 1.04 to 1.002, the peripheral magnetic field is not disturbed by rotation. ing. In a device using an electron beam, even if the degree of magnetization of the rolling device is small, there is a possibility that the control accuracy of the electron beam is reduced due to the influence of the magnetic field. In this application, the nonmagnetic level of the nonmagnetic stainless steel is insufficient, and a beryllium copper alloy or a titanium alloy having a high relative magnetic permeability of 1.001 or less may be used as a material for the rolling device. Proposed. For example, Japanese Unexamined Utility Model Publication No. Hei 5-79042 discloses a rolling bearing in which the race is made of a beryllium copper alloy and the rolling elements are made of ceramics. Japanese Patent Application Laid-Open No. 11-223221 discloses a rolling bearing in which a race is made of a titanium alloy and a rolling element is made of ceramics. However, beryllium copper alloys require careful handling during manufacture and use because part of the beryllium compound is a harmful substance. In addition, since the rolling device generates a high surface pressure at the contact point between the inner member and the outer member and the rolling element, the inner member, the outer member, and the rolling element have strength enough to withstand the surface pressure. Need to be formed. On the other hand, since the beryllium copper alloy can only have a hardness of about Hv400, if the beryllium copper alloy is used as the material of the rolling device, the strength that can withstand the surface pressure cannot be obtained, and the wear resistance is insufficient. It becomes. Further, in order to make the inner member, the outer member, and the rolling elements strong enough to withstand the surface pressure by using a titanium alloy, the titanium alloy is subjected to the following solution treatment and aging treatment. There is a need to do. First, as a solution treatment, after maintaining the titanium alloy at a temperature immediately above or immediately below the transformation point of the α phase and the β phase, by rapidly cooling from that temperature,
The metal structure is changed to a structure having a uniform β phase or a structure in which the α phase slightly remains in the β phase. Next, the titanium alloy after the solution treatment is heated to a temperature of about 350 to 600 ° C. and held for a predetermined time to finely precipitate the α phase from the β phase (precipitation hardening). In order to strengthen the titanium alloy by this method, it is necessary to add an element having a function of stabilizing the β phase as an alloy component of the titanium alloy. As the β-phase stabilizing element, Mo, V, Nb, Ta, Ag, Co, Cr,
Cu, Fe, Mn, Ni, Pb, Si, and W are mentioned. Titanium alloys containing ferromagnetic elements as these β-phase stabilizing elements have low non-magnetic levels. According to the present invention, there is provided a rolling device in which at least one of the inner member, the outer member, and the rolling element is made of a titanium alloy, having both a strength capable of withstanding a high surface pressure and a high non-magnetic level. The task is to provide. [0009] In order to solve the above-mentioned problems, the present invention provides an inner member disposed relatively inside and an outer member disposed outside, and a trajectory of both members. And at least one of the inner member, the outer member, and the rolling element is subjected to a solution treatment and an aging treatment. A rolling device made of the obtained β type (including near β type) or (α + β) type titanium alloy, wherein one of the inner member and the outer member relatively moves with respect to the other as the rolling element rolls. Wherein the titanium alloy has a content of a magnetic element represented by the following formula (1) of 0.3 or less. Magnetic element content = [Fe] +0.8 [Co] +0.3 [Ni] ‥‥ (1) (where [M] is the content (% by mass) of the element M in the titanium alloy Are shown.) Among the aforementioned β-phase stabilizing elements, Fe, C
o and Ni are elements that independently exhibit ferromagnetism. The degree of magnetism of these elements is expressed by a mass ratio of Fe: Co: Ni ≒ 1:
Considering that 0.8: 0.3, the content of the magnetic element was set as in the above equation (1). By setting the content of the magnetic element to 0.3% by mass or less, good non-magnetism can be obtained as a material for a rolling device of a device using an electron beam. The preferred value of the magnetic element content is 0.1 or less. The lower the magnetic element content, the higher the non-magnetic level. However, if the content is less than 0.01, the non-magnetic level does not substantially change. Further, these elements are elements that may be mixed as unavoidable impurity elements when obtaining a titanium alloy, and it is necessary to take measures to prevent the mixing of these elements in order to reduce the magnetic element content. As a result, the manufacturing cost increases. Therefore, the lower limit of the magnetic element content is set to 0.01. In order to obtain a strength capable of withstanding a high surface pressure while maintaining a high non-magnetic level by keeping the magnetic element content at 0.3 or less, it is necessary to include a β-phase stabilizing element other than Fe, Co and Ni. It is necessary to perform the above-mentioned solution treatment and aging treatment using a titanium alloy. Β other than Fe, Co, Ni
Among the phase stabilizing elements, Mo and Mo are effective elements for improving the strength.
Since V, Cr and Nb are used, it is preferable that one or more of these elements be selected and contained in the titanium alloy at a content of 2% by mass or more and 25% by mass or less.
Of these elements, it is particularly preferable to use Mo and V because of their ease of solid solution with Ti and a large β-phase stabilizing effect. The titanium alloys usable in the present invention include:
Ti-6Al-4V, Ti-8Al-Mo-V, Ti-
6Al-2Sn-4Zr-2Mo, Ti-15V-3C
r-3Sn-3Al, Ti-6Al-6V-2Sn, T
i-5Al-2Sn-2Zr-4Cr-4Mo, Ti-
6Al-2Sn-4Zr-6Mo, Ti-13V-11
Cr-3Al, Ti-15Mo-5Zr-3Al, Ti
-22V-4Al. Further, in order to obtain a strength capable of withstanding a high surface pressure, the surface hardness of the inner member, the outer member, and the rolling elements is set to Hv400 or more, preferably Hv450. Thereby, the wear resistance and load resistance required for the rolling device are obtained, and the rolling life is improved. In addition, by performing oxidation treatment on the surface of the inner member, outer member, or rolling element made of a titanium alloy, or by forming a lubricating film such as a fluorine oil baked film, wear resistance and slidability are improved. May be improved. Examples of the oxidation treatment include a method of forming rutile-type or anatase-type titanium oxide having a thickness of 20 nm or more by heat oxidation or anodic oxidation. In the rolling device according to the present invention, the inner member and the outer member may be a β-type or (α + β) -type titanium having a magnetic element content represented by the above formula (1) of 0.3% by mass or less. It is preferable that the rolling elements are made of a material made of an alloy, and the rolling elements are made of non-magnetic ceramics. Non-magnetic ceramics include silicon nitride, silicon carbide, aluminum oxide,
Zirconium oxide and the like can be mentioned. Further, in a measuring instrument using an electron beam, electric charges may accumulate in an insulating portion and measurement accuracy may be reduced. Therefore, for devices that require conductivity as well as non-magnetism, conductive ceramics that have been given conductivity by the addition of TiN or the like may be used as the rolling element material,
It is preferable to use a ceramic rolling element formed with a conductive coating made of TiN or the like. In the rolling device of the present invention, the constituent members not formed of the above-mentioned material (including the retainer and the seal when the retainer and the seal are provided) must be formed of a non-magnetic material. There is. Examples of non-magnetic materials other than the above materials include ceramics, synthetic resin, austenitic stainless steel such as SUS304, pure titanium for industrial use, and titanium alloy. Embodiments of the present invention will be described below. Using each material shown in Table 1 below, a raceway ring (inner ring and outer ring) and a rolling element for a deep groove ball bearing with a nominal number 608 were produced by the following method. In Nos. 1 to 10, a bar made of a titanium alloy having the composition shown in Table 1 below was prepared, and the bar was subjected to a solution treatment and an aging treatment, followed by cutting with a lathe and further finishing. By performing the processing, an inner ring and an outer ring for a deep groove ball bearing with a nominal number of 608 were produced. Solution treatment is performed at 750 to 1050 ° C for 1 hour.
After holding for a time, the cooling was performed by rapidly cooling to room temperature with water cooling or gas cooling. Aging treatment is 400-550
After holding in a furnace at 4 ° C. for 4 to 60 hours, cooling was performed in the furnace. In No. 11, a bar made of SUS440C was prepared, and the bar was cut by a lathe and further finished to obtain an inner ring and an outer ring for a deep groove ball bearing having a nominal number of 608. Was prepared. As the rolling elements, a ball made of silicon nitride, a ball made of silicon carbide,
A ball made of alumina, a ball made of zirconia, a ball made of silicon nitride with a TiN film formed by an arc deposition method, and a ball made of SUS440C were prepared. A crown-shaped cage made of fluororesin was prepared as the cage. The inner ring, the outer ring, and the balls made of SUS440C are subjected to a heat treatment by a usual method to have a surface hardness of Hv450 or more. The surface hardnesses of the inner and outer rings of Nos. 1 to 10 were all Hv450 or more. Inner ring, outer ring and ball (rolling element) produced in this way
Were assembled in a configuration shown in Table 1 below to assemble a rolling bearing. The same inner ring and outer ring were used for each bearing, and Table 1 shows them as races. Further, the “magnetic element content” of the titanium alloys forming the orbital rings of Nos. 1 to 10 was calculated using the equation (1), and the values are shown in Table 1 below. Using these rolling bearings Nos. 1 to 11, a test for examining non-magnetism was conducted. This test was performed using the apparatus shown in FIG. This device comprises a rotating shaft 2 on which a rolling bearing 1 is mounted, a permanent magnet 3 arranged near the rolling bearing 1, and a Gauss meter measuring terminal 4 arranged on the opposite side of the permanent magnet 3. With this device, the rolling bearing 1 was rotated at a rotation speed of 100 rpm near the permanent magnet 3, and a change in magnetic flux density generated near the rolling bearing 1 at that time was measured by a Gauss meter measuring terminal 4. Then, the variation width of the magnetic flux density measured at the Gauss meter measuring terminal 4 was examined, and a relative value was calculated with the variation width of No. 1 being “1.0”. The results are also shown in Table 1 below. FIG. 2 is a graph showing the relationship between the “fluctuation in magnetic flux density (relative value)” and the “magnetic element content” obtained from the results. [Table 1] As can be seen from the results of this test, (1)
The rolling bearings Nos. 1 to 6 provided with a raceway made of a titanium alloy having a magnetic element content of 0.3 or less and a ceramic ball have a magnetic element content of 0.3 of the formula (1).
The fluctuation width of the magnetic flux density is smaller than that of the rolling bearings Nos. 7 to 9 including the races made of a titanium alloy and the ceramic balls. That is, rolling bearing Nos. 1 to 6
Has a higher non-magnetic level than the rolling bearings Nos. 7 to 9, and thus can be suitably used in a measuring device using an electron beam. Further, the content of the magnetic element in the formula (1) is 0.3
Even with a raceway made of the following titanium alloy,
Rolling bearing whose ball is made of SUS440C (No. 1
0) indicates that the non-magnetism is poor. Furthermore, the race is SUS
The rolling bearing made of 440C and having a ball made of silicon nitride (No. 11) also has poor non-magnetism. FIG. 3 is a view showing a part of a measuring and processing apparatus for a disk-shaped object using an electron beam, and a guide roller 6 for positioning the disk-shaped object 5.
However, it is constituted by a rolling bearing 60 shown in FIG. The rolling bearing 60 includes an inner ring 61, an inclined outer ring 62 whose outer diameter changes in the axial direction, a ball (rolling element) 63, and a retainer 64. The guide roll 6 is configured by arranging two rolling bearings 60 such that small-diameter portions of the outer race 62 overlap each other. In this measuring and processing apparatus, while the disk-shaped object 5 such as a silicon wafer is positioned by the guide roll 6, the disk-shaped object 5 is irradiated with an electron beam 7 to measure or process the disk-shaped object. . Therefore, as the two rolling bearings 60 constituting the guide roll 6, the inner ring 61 and the outer ring 62 are made of the titanium alloy specified in the present invention, the ball 63 is made of silicon nitride, and the TiN film is formed. Since the electron beam 7 is prevented from being bent due to the rotation of the rolling bearing 60 by using a rolling bearing having a high non-magnetic level in which the device 64 is made of a fluororesin, the accuracy of the measuring and processing apparatus can be improved. High measurement and processing become possible. The present invention can be applied to a rolling support device (for example, a ball screw or a linear guide) other than the rolling bearing. In a ball screw, the screw shaft is the inner member,
The nut is the outer member. In the linear guide, the guide rail is an inner member, and the slider is an outer member. As described above, according to the present invention,
As a rolling device in which at least one of the inner member, the outer member, and the rolling element is made of a titanium alloy, a rolling device having both strength capable of withstanding a high surface pressure and a high nonmagnetic level is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a test apparatus used for checking non-magnetism in an embodiment. FIG. 2 is a graph showing the relationship between “fluctuation in magnetic flux density (relative value)” and “content of magnetic element” obtained by a test of an embodiment. FIG. 3 is a diagram showing a part of a measuring and processing apparatus for a disk-shaped object using an electron beam. FIG. 4 is a sectional view showing a rolling bearing constituting a guide roller of the apparatus of FIG. 3; [Description of Signs] 1 Rolling bearing 2 Rotary shaft 3 Permanent magnet 4 Gauss meter measuring terminal 5 Disc-shaped object 6 Guide roller 7 Electron beam 60 Rolling bearing 61 Inner ring 62 Outer ring 63 Ball (rolling element) 64 Cage

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16H 25/24 F16H 25/24 BF Term (Reference) 3J062 AB22 AC07 BA40 CD45 CD54 CD62 3J101 AA03 AA32 AA42 AA52 AA53 AA62 BA10 BA70 DA20 EA02 EA33 EA78 FA60 GA55 GA60

Claims (1)

Claims 1. An inner member and an outer member disposed relatively inside and an outer member disposed outside, and a plurality of rollers disposed between the raceway grooves of both members so as to freely roll. And at least one of the inner member, the outer member, and the rolling member is a β-type or (α + β) -type titanium alloy obtained by performing a solution treatment and an aging treatment. In one embodiment, the rolling element rolls so that one of the inner member and the outer member moves relative to the other, and the titanium alloy has a magnetic element content represented by the following formula (1): Is 0.3 or less. Magnetic element content = [Fe] +0.8 [Co] +0.3 [Ni] ‥‥ (1) (where [M] indicates the content (% by mass) of the element M in the titanium alloy. )