JP2001116659A - Bearing inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing inspection device capable of centering a ball bearing in a dry state without using grease for a rotary shaft at inspection time. SOLUTION: In a bearing inspection device 10, plural herringbone grooves 14 as recessed parts are arranged on an outer peripheral surface 13 of a rotary shaft 11, and an inner race 141 of a ball bearing 140 is installed on the rotary shaft 11 in a rotating state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing inspection device, and more particularly to a bearing inspection device suitable for a vibration inspection of a ball bearing used in a hard disk drive.

[0002]

2. Description of the Related Art FIG. 14 shows a bearing inspection device 150 for measuring vibration generated from a ball bearing 140 during rotation. In the ball bearing 140, a number of balls 143 are arranged between an inner raceway surface formed on the outer peripheral surface of the inner ring 141 and an outer raceway surface formed on the inner peripheral surface of the outer ring 142. Inner ring 141, outer ring
142 is a bearing ring, and ball 143 is a rolling element. On the other hand, the bearing inspection device 150 includes the motor 1 through the pulleys 151 and 152 and the belt 153 when the inner ring 141 of the ball bearing 140 is inserted.
A rotating shaft 155 rotatably driven by 54; a pressing member 156 disposed coaxially rotatably with respect to the rotating shaft 155; and a pressing member 156 for pressing an end surface (the left end surface in FIG. 14) of the outer ring 142;
Measurement means 157 for measuring the vibration by contacting the outer peripheral surface of the 140 outer ring 142 is provided.

The bearing inspection device 150 inserts the inner ring 141 of the ball bearing 140 into the rotating shaft 155 while rotating the rotating shaft 155, and presses the pressing member 156 against the end surface of the outer ring 142 to preload the ball bearing 140. And the measuring means 157
Vibration generated in the rolling portion between the inner raceway surface or the outer raceway surface and the ball by contacting the outer peripheral surface of 142 is measured.

The bearing inspection device 150 shown in FIG. 14 measures the vibration by bringing the measuring means 157 into contact with the outer peripheral surface of the outer ring 142. The bearing inspection device 150 shown in FIG. The vibration may be measured by inserting the outer ring 142 of the ball bearing 140 into the insertion portion of the inner ring 141 and rotating the same, and bringing the measuring means 157 into contact with the inner peripheral surface of the inner ring 141.

[0005]

By the way, the bearing inspection device 150 described above inserts the inner ring 141 into the rotating shaft 155 when inspecting the ball bearing 140.
There is a case where the axis of the inner ring 141 is fixed in a state where the axis of the inner ring 141 is inclined with respect to the axis of, and there is a possibility that the measurement value may include an error. In addition, since the inner ring 141 is attached to and detached from the rotating shaft 155 every time the ball bearing 140 is inspected, uneven wear, deformation, and the like are likely to occur on the outer peripheral surface, and the above-described problem is more likely to occur. For this reason, conventionally, the inner ring 141 of the ball bearing 140 is lubricated with a very small amount of grease on the peripheral surface of the rotating shaft 155 and the inner diameter surface of the bearing in advance, and the lubricating film of the grease prevents metal contact with the inner ring 141, A method of centering is often used.

In recent years, ball bearings used in hard disk drives (hereinafter abbreviated to HDDs) of personal computers, etc., require that the entire surface of each member be dry and free of oil or the like from the viewpoint of its application. It has become. For this reason, when inspecting the ball bearing used for the HDD, a method of applying grease to the outer peripheral surface of the rotating shaft 155 or the inner diameter surface of the bearing cannot be used.

The present invention has been made in view of the above-mentioned problems, and has as its object to center a ball bearing in a dry state without using grease or the like on an outer peripheral surface of a rotating shaft or an inner diameter surface of a bearing during inspection. It is to provide a possible bearing inspection device.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention relates to a method for reducing the vibration generated between a ball in an operating ball bearing and at least one of an outer raceway surface and an inner raceway surface. A rotating shaft that holds and rotates one of the outer ring and the inner ring for measurement, and extends in a direction approaching from a direction away from the rotating shaft, and a fixed shaft of the outer ring and the inner ring A bearing inspection device comprising: a holding member capable of pressing an end face of a raceway to be formed; and measuring means for measuring vibration by contacting a peripheral surface of a raceway ring serving as a fixed axis of the outer race and the inner race. ,
The rotating shaft has a holding surface for holding one of the outer ring and the inner ring in a detachable manner, and the holding surface is provided with a plurality of recesses.

Here, as the holding surface, the outer circumferential surface of the rotary shaft that can be inserted into the inner ring of the ball bearing, that is, the outer diameter holding surface, or the disk-like inner circumferential surface of the ball bearing into which the outer ring can be inserted, That is, the inner diameter holding surface and the like can be exemplified. The outer diameter holding surface may have its outer diameter dimension set slightly smaller than the inner diameter dimension of the inner ring. On the other hand, the inner diameter holding surface may have its inner diameter set slightly larger than the outer diameter of the outer ring.

When the outer diameter holding surface is employed as the recess, for example, straight, broken, or curved grooves formed along the generatrix direction, circumferential direction, spiral direction, or the like of the outer diameter holding surface may be used. Or fine holes uniformly formed over the entire outer diameter holding surface. The groove as the concave portion may be formed at a radially uniform position about the axis of the outer diameter holding surface, and preferably has an open end in the continuous direction. The cross-sectional shape of such a groove is, for example, rectangular,
A polygonal shape, a semicircular shape, a semielliptical shape, and the like can be selected, and the presence or absence of symmetry with respect to a surface along the continuous direction is also arbitrary.
Such a groove can be formed by, for example, performing machining such as etching, electric discharge machining, rolling, cutting, sand blasting, or shot blasting on the outer peripheral surface of the rotating shaft. Sand blasting, shot blasting, and the like can also be employed when minute holes are formed in the holding surface as recesses.

In the case where, for example, the outer peripheral surface of a rotary shaft formed in a cylindrical shape is employed as a holding surface, these grooves and holes may be formed as a collet groove or a through hole communicating between the inside and outside of the rotary shaft. Then, a predetermined gas may be injected from the inside to the outside of the rotating shaft through these collet grooves and through holes.

Further, as the concave portion in the present invention, a structure in which a holding surface is formed of, for example, a porous material may be employed in addition to the mechanically formed grooves and holes. here,
The porous material may be any of an open-cell type and a closed-cell type. When the porous material is of the open-cell type, a predetermined gas may be injected from the inside to the outside of the rotating shaft.

In the bearing inspection apparatus thus configured, since the holding surface is provided with a plurality of recesses, the outer diameter of the outer ring or the inner diameter of the inner ring is formed so that a small gap is formed with respect to the holding surface. If the dimensions are set appropriately, by inserting the ball bearing after rotating the rotating shaft, an air film is formed between the holding surface and the outer peripheral surface of the outer ring or the inner peripheral surface of the inner ring by each concave portion, so that the air surface is formed on the holding surface. It is formed uniformly along the circumferential direction, and a dynamic pressure is generated according to the relative peripheral speed of the ball bearing and the rotating shaft.

In this bearing inspection device, if a predetermined gas can be injected from the recess, the outer diameter of the outer ring or the inner diameter of the inner ring is set as appropriate, and the recess is inserted with the ball bearing inserted. When a gas is injected from the inner ring, a static pressure is generated between the holding surface and the outer peripheral surface of the outer ring or the inner peripheral surface of the inner ring.

In other words, in such a bearing inspection device, even if the holding surface of the rotating shaft is formed so as not to contact the outer peripheral surface of the outer race or the inner peripheral surface of the inner race in the ball bearing, The bearing can be reliably maintained coaxial with the rotating shaft. Therefore, in this bearing inspection device, unlike the related art, when inspecting the ball bearing, there is little possibility that the inner ring or the outer ring is inclined and fixed with respect to the rotating shaft, or uneven wear or deformation of the rotating shaft occurs. Will be.

Further, in this bearing inspection device, since the ball bearing is held through an air film uniformly formed along the holding surface, grease is applied to the outer peripheral surface of the rotating shaft and the inner diameter surface of the bearing as in the prior art. Unlike the method of applying oil, since the ball bearing can be centered in a dry manner, it can be applied to, for example, the inspection of a ball bearing used in an HDD, thereby achieving the above-described object.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the embodiments described below, the members and the like already described in FIG. 14 are denoted by the same reference numerals or corresponding reference numerals in the drawings to simplify or omit the description.

As shown in FIG. 1, a bearing inspection apparatus 10 according to a first embodiment of the present invention is a conventional bearing inspection apparatus for measuring vibrations generated in an operating state from a ball bearing 140 used for an HDD or the like. Similarly to the device, the rotating shaft 11 inserted into the inner ring 141 of the ball bearing 140 extends from the direction away from the rotating shaft 11 toward the approaching direction, and
A pressing member 156 capable of pressing an end face (left end face in FIG. 1) of the outer ring 142 of No. 0 and measuring means 157 for measuring vibration by contacting the outer peripheral surface of the outer ring 142 of the ball bearing 140 are constituted. I have.

The rotating shaft 11 has a flange 12 which can be brought into surface contact with the end face of the inner ring 141, and the outer diameter of the outer peripheral surface 13 from the flange 12 to the end is slightly smaller than the inner diameter of the inner ring 141. Is set. According to the present invention, the rotating shaft 11 is provided with a plurality of herringbone grooves 14 as recesses on an outer peripheral surface 13 which is a holding surface of the rotating shaft 11.

As shown in FIG. 2, the herringbone groove 14
Has a rectangular cross section bent in a substantially V-shaped plane,
It is provided so as to expand in the rotation direction of 11. These herringbone grooves 14 are formed such that one end in the continuous direction is open to the outside from a tapered surface 13A provided at an end of the outer peripheral surface 13. The rotating shaft 11 has an outer peripheral surface along which the herringbone grooves 14 extend in the circumferential direction of the rotating shaft 11.
13 are formed at equal intervals on the entire circumference.

In FIG. 2, d: the outer diameter of the rotating shaft 11 α: the plane intersection angle of the groove with respect to the axis of the rotating shaft 11
H ₀ : groove depth dimension ΔR: (inner ring inner diameter dimension-rotating shaft outer diameter dimension d) / 2 = radial gap dimension (bearing gap) H: h ₀ / ΔR = groove depth ratio δ ₁ : Groove width dimension δ ₂ : land width dimension γ: δ ₂ / δ ₁ = groove width ratio l ₁ , l ₂ : groove length dimension from the bent portion along the generatrix (hereinafter referred to as groove length dimension) L: The length of the outer peripheral surface in the axial direction (l ₁ + l ₂ ).

Next, an inspection procedure by the bearing inspection device 10 according to the present invention will be described. First, the motor 154 is started to rotate the rotating shaft 11, and the ball bearing 140 is coaxially arranged on the rotating shaft 11 by appropriate means. Next, the inner ring 141 of the ball bearing 140 is mounted on the rotating shaft 11. A lightly inserted and pressable pressing member 156 applies a preload to the end face of the flange 12 of the rotating shaft 11. At this time, coaxial arrangement is possible by using a V block or the like. At this time, the rotating shaft 11 and the inner ring 141
There is a very small gap between
Since the inner ring 141 rotates relatively and the plurality of herringbone grooves 14 are formed on the outer peripheral surface 13 of the rotating shaft 11, a dynamic pressure corresponding to each herringbone groove 14 is generated, thereby rotating the inner ring 141. The inner ring 141 is coaxially arranged with respect to the shaft 11, that is, the inner ring 141 is centered.

Here, the pressure p ₀ generated between the rotating shaft and the inner peripheral surface of the inner ring 141 by each herringbone groove 14 is obtained by the following equation. (P ₀ -pa) = P · 6ηωR ² / (ΔR) ² P: Value determined by the planar shape (geometric shape) of the concave portion pa: Ambient pressure η: Lubricant viscosity (viscosity of air in a dry state) ω (2πn ): Rotational angular velocity (n is rotational velocity: min)
^-1 (rpm)

By the way, the inner ring is
When the 141 is inserted, the smaller the radial gap size ΔR, the greater the generated dynamic pressure.
However, if the radial gap dimension ΔR is too small, the possibility that the rotating shaft 11 and the inner ring 141 come into contact with each other increases. Therefore, the radius gap size ΔR is preferably 2 μm to 10 μm.

The generated pressure of the dynamic pressure increases as the axial length L of the outer peripheral surface 13 increases.
It is determined by the width of 41. Further, as for the groove depth ratio H and the groove width ratio γ, H ≒ 1 and γ ≒ 1 have the maximum values,
Usually, it is selected from the range of H = 0.5-2 and γ = 0.5-2. Further, the groove angle α differs depending on the groove depth ratio H and the groove width ratio γ, but usually α = 15 degrees to 45 degrees (0.26 rad to 0.97 ra).
d) Select from the range. The axial length L of the outer peripheral surface 13 is l ≒ l ₂ .

The groove angle α is α> 45 degrees (0.97 rad)
When designed to α ≒ 90 degrees (1.6 rad), the groove herringbones 14 become parallel and the dam effect appears.
It is used in the same way as when designed at 15 degrees to 45 degrees (0.26 rad to 0.97 rad). The number N of the herringbone grooves 14 is
If it is less than a certain number, the pressure difference between the groove and the land becomes large, and the dynamic pressure effect becomes small. If it is more than a certain number, a shape error during processing is likely to occur. The number N of the herringbone grooves 14 is
The width [delta] ₁ and the land width [delta] ₂ of set to be 0.2mm or more because it is common, and N = 5 to 15.

In consideration of the above, the specifications of the rotating shaft in the first embodiment are determined by taking into account the variation in machining, etc., ΔR = 2 μm to 10 μm H = 0.5 to 2 γ = 0.5 to 2α = 15 degrees to 45 degrees (0.26 rad to 0.97 rad) l ₁ = l ₂ .

According to the bearing inspection device 10 described above,
Since a plurality of grooves 14 are provided on the outer peripheral surface 13 which is a holding surface of the rotating shaft 11, the outer diameter of the outer peripheral surface 13 is set to be slightly smaller than the inner diameter of the inner ring 141 constituting the ball bearing 140. In addition, if the rotating shaft 11 is attached so that the rotating shaft 11 is inserted relatively to the inner ring 141 with the rotating shaft 11 rotated,
Dynamic pressure is generated by each herringbone groove 14, and the inner ring 141 is kept coaxial with the rotating shaft 11 via the air film.
That is, according to the bearing inspection device 10, when inspecting the ball bearing 140, there is a possibility that the inner ring 141 is fixed to be inclined with respect to the rotating shaft 11, or that there is a possibility that the rotating shaft 11 may be unevenly worn or deformed. Can be reduced in comparison.

According to the bearing inspection device 10, the inner ring 141 is kept coaxial with the rotating shaft 11 via the air film, so that the outer peripheral surface of the rotating shaft 11 and the inner diameter surface of the bearing are different from the conventional case. Unlike dry ball grease, dry ball bearings 1
Since the 40 inner rings 141 can be centered, the present invention can be applied to inspection of ball bearings used in HDDs.

FIG. 3 shows a second embodiment according to the present invention. In each of the following embodiments including the second embodiment, only the rotating shaft is different from the first embodiment described above. Therefore, only the rotating shaft will be described, and the others will be omitted. The rotating shaft 21 of the second embodiment has a hollow portion 25 provided from an end portion to a predetermined position along the axial direction, and a collet groove 24 penetrating from the outer peripheral surface 23 to the hollow portion 25 as a concave portion. I have. These collet grooves 24 are formed linearly along the generatrix of the outer peripheral surface 23 at radially uniform positions about the axis of the rotating shaft 21, and one end reaches the end surface of the flange 22, The other end has reached the end of the rotating shaft 21.

According to the second embodiment, since a plurality of collet grooves 24 are provided on the outer peripheral surface of the rotary shaft 21 having a diameter several μm to several tens μm larger than the inner diameter of the bearing, each collet groove 24 is formed. A centering action occurs between the outer peripheral surface 23 of the rotating shaft 21 and the inner peripheral surface of the inner ring of the ball bearing. Therefore, according to the second embodiment, there is little possibility that the inner ring is fixed to the rotating shaft 21 at an angle, or uneven wear or deformation of the rotating shaft 21 occurs. On the other hand, an effect similar to that of the above-described first embodiment that the ball bearing can be held coaxially can be obtained.

In addition, according to the second embodiment, since the collet groove 24 that reaches the end of the rotary shaft 21 is employed as each concave portion, an error occurs in the initial shape of the rotary shaft 21. Or even if the rotating shaft 21 is eccentric,
The effect that the shape error and the eccentricity can be eliminated by partially and independently deforming the outer peripheral surface 23 of the rotating shaft 21 is also obtained.

FIG. 4 shows a third embodiment according to the present invention. The rotating shaft 31 of the third embodiment has a hollow portion 35 provided from a base end (not shown) to a predetermined position along an axis, and a concave portion extending from an end of the hollow portion 35 to an outer peripheral surface.
A plurality of outlet holes 36 communicating with 33 are provided. The blowout holes 36 are provided radially from the end of the hollow portion 35. Such a rotating shaft 31 can blow out a gas such as air from the base end to the outer peripheral surface 33 through the hollow portion 35 and each of the blowout holes 36.

In the third embodiment, the inner ring of the ball bearing is connected to the rotating shaft while the gas is blown from the outer peripheral surface 33.
When attached to 31, the air film is formed between the outer peripheral surface 33 and the inner peripheral surface of the inner ring by the static pressure, whereby the inner ring is maintained coaxial with the rotating shaft 33. In the third embodiment, if the air blowing is interrupted during the measurement, the coaxial state of the inner ring with respect to the rotating shaft 31 is stabilized,
There is no danger that the measurement accuracy will deteriorate.

Therefore, according to the third embodiment, since gas can be blown out from the outer peripheral surface 33 of the rotating shaft 31, when the inner ring of the ball bearing is attached, the inner ring is fixed to the rotating shaft 31 by the static pressure effect. Since the coaxial state can be maintained, the first
The same effects as in the embodiment and the second embodiment can be obtained.

FIG. 5 shows a fourth embodiment according to the present invention. The rotation shaft 41 of the fourth embodiment is the same as the first shaft described above.
As in the embodiment, a plurality of herringbone grooves 44 that are bent in a substantially V-shaped plane are provided on the outer peripheral surface 43 as concave portions.
In the rotary shaft 41, two herringbone grooves 44 are provided on the outer peripheral surface 43 at predetermined intervals in the axial direction. In the fourth embodiment, the same effects as those of the first embodiment can be obtained.

FIG. 6 shows a fifth embodiment according to the present invention. In the rotary shaft 51 of the fifth embodiment, a groove 54 that is continuous in the spiral direction along the outer peripheral surface 53 is employed as a concave portion. These grooves 54 are provided in two rows at predetermined intervals in the axial direction, and each row is formed symmetrically with respect to a surface along the radial direction of the rotating shaft 51 as a boundary. The intersection angle of each groove 54 with respect to the generatrix of the outer peripheral surface 53 is 15 to 45 degrees (0.26 rad).
~ 0.97rad). Fifth such
In the embodiment, the same effects as those in the first embodiment can be obtained.

FIG. 7 shows a sixth embodiment according to the present invention. The rotating shaft 61 of the sixth embodiment has the same basic structure as the rotating shaft of the above-described second embodiment, and has a hollow portion 25 in which an elastic body 66 is sealed. According to such a sixth embodiment, the basic structure is the same as that of the rotary shaft of the above-described second embodiment, so that the same effects as those of the rotary shaft of the second embodiment can be obtained, and the hollow portion can be obtained. Since the elastic body 66 is sealed in 25, the processing of the collet groove 24 as a recess becomes easy, and the rigidity of the outer peripheral surface 23 is improved as compared with the case where the elastic body 66 is not sealed in the hollow part 25. The effect is obtained.

FIG. 8 shows a seventh embodiment according to the present invention. The rotary shaft 71 of the seventh embodiment has a hollow portion 35 extending from a base end (not shown) to a flange 72 along an axis, and a cylindrical porous material 74 having a predetermined thickness is provided on the flange 72. Glued. That is, the rotating shaft 71 is
The outer peripheral surface 73 inserted into the inner ring of the ball bearing is made of a porous material 74.
The fine recess is provided over the entire outer peripheral surface 73. The porous material 74 is, for example, a bronze porous material, graphite, ceramic porous material, or the like, and is arranged such that the inner peripheral surface and the outer peripheral surface 73 communicate with each other by continuous porosity, and the inner diameter matches the hollow portion 35. I have.

The rotating shaft 71 is configured such that a gas such as air sent from the base end can be blown from the outer peripheral surface 73 through the hollow portion 35 and the porous material 74. Accordingly, if the inner ring of the ball bearing is attached to the rotating shaft 71 in a state where gas is blown from the outer peripheral surface 73, the rotating shaft 71 becomes a hydrostatic bearing that centers the inner ring with respect to the rotating shaft 71.

A qualitative relational expression representing the load capacity, dynamic rigidity and damping of the hydrostatic bearing is shown below. Load capacity: W∝Ae · Ps Dynamic rigidity: W∝ξ · Ae · Ps / h ₀ Damping: C∝η · Xc · ΔR ³

Here, W: load capacity Ae: effective bearing area Ps: gas supply pressure K: rigidity ξ: coefficient relating to dynamic rigidity ΔR: bearing clearance C: damping Xc: coefficient relating to damping η: viscosity of lubricating oil

From these facts, the load capacity W increases as the bearing effective area Ae and the gas supply pressure Ps increase. The effective receiving area Ae is determined by the inner diameter dimension and the bearing width dimension of the bearing. On the other hand, the gas supply pressure Ps is usually set to 19.6 × 10
⁴ Pa to 58.8 × 10 ⁴ Pa (2 kgf / cm ^{2 to} 6 kgf / c
m ² ). Further, in order to prevent leakage of gas to the end of the rotating shaft 71 and to secure an appropriate damping C as a hydrostatic bearing, the bearing gap ΔR is not made larger than necessary.
Set to 2 μm to 15 μm.

According to the seventh embodiment, fine recesses are provided over the entire outer peripheral surface 73 of the rotary shaft 71 by the porous material 74, and gas is blown out from these recesses, thereby providing a hydrostatic bearing. As a result, the inner ring of the ball bearing can be reliably and easily centered with respect to the rotating shaft 73.

FIG. 9 shows an eighth embodiment according to the present invention. The rotating shaft 81 of the eighth embodiment is basically configured in the same manner as the rotating shaft 31 of the third embodiment described above, but has a cylindrical, conical, or planar rectangular shape at the opening edge of each blowout hole 36. Are provided. According to the eighth embodiment, since the configuration is basically the same as that of the third embodiment described above, if the inner ring of the ball bearing is attached to the rotating shaft 81 while gas is blown from the outer peripheral surface 83, An air film is formed between the outer peripheral surface 83 and the inner peripheral surface of the inner race by the static pressure, whereby the inner race is maintained coaxial with the rotating shaft 83. According to the rotating shaft 81 of the eighth embodiment, since the depression 84 is provided at the opening edge of each blowout hole 36, the static pressure is wider than that of the rotating shaft of the third embodiment described above. Occurs, thereby improving the stability as a hydrostatic bearing.

FIG. 10 shows a ninth embodiment according to the present invention. The rotation shaft 91 of the ninth embodiment is the same as the first shaft described above.
This is a mode in which the embodiment and the third embodiment are combined. Specifically, the rotating shaft 91 is provided with a plurality of herringbone grooves 14 near the flange 92 on the outer peripheral surface 93, and a hollow portion 35 is provided from a base end (not shown) to a predetermined position along the axis. The blowout hole 36 communicating with the hollow portion 35 is disposed on the outer peripheral surface 93 near the tapered surface 93A. Also in such a ninth embodiment,
The desired effect can be obtained.

FIG. 11 shows a tenth embodiment according to the present invention. The rotating shaft 101 of the tenth embodiment is a combination of the third and fifth embodiments described above. Specifically, the rotary shaft 101 is provided with two rows of grooves 104 at predetermined intervals in the axial direction on the outer peripheral surface 103, and has a hollow portion 35 extending from a base end (not shown) to a predetermined position along the axis. The blowout holes 36 provided and communicating with the hollow portions 35 are arranged between the rows of the grooves 104 on the outer peripheral surface 93. Also in the tenth embodiment, a desired effect can be obtained.

Next, for a first ball bearing and a second ball bearing having different inner diameters of the inner ring and outer diameters and widths of the outer ring, a plurality of types of rotating shafts manufactured according to the present invention are provided. FIG. 12 shows the results of vibration measurement using a conventional rotating shaft that is coated with grease while performing vibration measurement. Table 1 shows the specifications of Examples 1 to 7 and Conventional Examples 1 to 4 in FIG.

[0049]

[Table 1]

Here, the first ball bearing has an inner ring inner diameter of 5 mm, the outer ring outer diameter 13 mm and a width 3 mm, and the second ball bearing has an inner ring inner diameter 4 mm and an outer ring outer diameter. It has a width of 9 mm and a width of 2.3 mm.

In Examples 1 and 2, vibrations were measured in the first ball bearing and the second ball bearing, respectively, using the rotating shaft manufactured according to the above-described first embodiment. The rotary shafts of the first and second embodiments have a diameter corresponding to the inner diameter of the inner ring of the ball bearing, and the groove angle α of the herringbone groove provided on each outer peripheral surface is 30 degrees (0.52 rad). , the groove depth dimension h ₀ of about 3 [mu] m, the groove width ratio γ is 1, the number N of the herringbone grooves 10, radial gap dimension ΔR is the 2Myuemu～5myuemu.

Further, in Example 3, vibration was measured in the second ball bearing using a rotating shaft manufactured according to the above-described second embodiment. The rotating shaft of the third embodiment has a diameter corresponding to the inner diameter of the inner ring of the ball bearing, specifically, a diameter obtained by adding 6 μm to the diameter of the conventional rotating shaft, and the number of collet grooves is eight. , The groove width dimension is 0.2 mm.

In Examples 4 to 7, vibrations were measured in the first ball bearing and the second ball bearing, respectively, using the rotating shaft manufactured according to the above-described seventh embodiment. The rotating shafts of the first and second embodiments have a diameter corresponding to the inner diameter of the inner ring of the ball bearing, and a fine concave portion made of graphite porous material is provided over the entire outer peripheral surface, and the gas supply pressure Ps Is 44.1Ps × 10 ⁴ Pa (
4.5 kgf / cm ² ), and the bearing gap ΔR is 5 μm to 10 μm.

In the fourth and fifth embodiments, the first
In the vibration measurement of the ball bearing and the second ball bearing, the vibration was measured while the supply of the gas blown from the outer peripheral surface of the rotating shaft was continued. On the other hand, in Example 6 and Example 7, when measuring the vibration in the first ball bearing and the second ball bearing, the supply of the gas blown from the outer peripheral surface of the rotating shaft was stopped, and the vibration was measured.

On the other hand, in Comparative Examples 1 and 2, vibration measurement was performed on the first ball bearing and the second ball bearing without using grease on the outer peripheral surface of the rotating shaft using the conventional rotating shaft. Was. Further, in Comparative Examples 3 and 4, a conventional rotary shaft was used, and grease was applied to the outer peripheral surface of the rotary shaft to measure the vibration in the first ball bearing and the second ball bearing.

In Examples 1 to 7 and Comparative Examples 1 to 4, the axial preload for the first ball bearing was 2.45 N (0.25 kgf), and the axial preload for the second ball bearing was 4.90 N ( 0.5kgf) and the rotation axis is 3600min
Rotation was performed at ^-1 (rpm) to measure the vibration of ten ball bearings, and the average value was obtained. FIG. 12 is a graph showing relative values based on the average value of Comparative Example 3.

According to FIG. 12, the first to seventh embodiments are described.
Indicates that the average value of the measurement results is lower than that of Comparative Examples 1 to 4, indicating the effectiveness of providing the concave portion on the outer peripheral surface of the rotating shaft. In Examples 4 to 7, among Examples 6 and 7, the average value of the measurement results is lower than that in Examples 4 and 5 in which the gas is continuously blown out during the measurement. The effectiveness of stopping the blowing of gas is understood.

The bearing inspection device of the present invention is not limited to the above embodiments, but can be appropriately modified and improved. For example, in each of the above-described embodiments, the bearing inspection device that employs, as a holding surface, an outer peripheral surface of a rotating shaft that can be inserted into and removed from an inner peripheral surface of an inner ring that constitutes a ball bearing is exemplified. Is the bearing inspection device shown in Fig. 13 1
Also includes 30.

That is, the bearing inspection device 130 shown in FIG.
Is the inner diameter holding surface on the end surface (left end surface in FIG. 13) of the rotating shaft 131.
133 are formed. The inner diameter holding surface 133 is
It is provided by fitting a substantially annular porous material 134 into a step formed by performing a counterbore process along the axial direction from the end face of the base member. The inner diameter holding surface 133 has an inner diameter set slightly larger than the outer diameter of the outer ring 142 in the ball bearing 140, and communicates with a hollow portion 135 provided in the rotating shaft 131.

The bearing inspection device 130 inserts the outer ring 142 of the ball bearing 140 into the inner diameter holding surface 133 of the rotating shaft 131 which rotates while blowing gas from the inner peripheral surface of the porous material 134.
A preload is applied to the ball bearing 140 by pressing the end face of the inner ring 141, and then, while the gas is being blown out, or the gas blowing is stopped, or after the blowing is stopped, the measuring means (not shown) is connected to the inner periphery of the inner ring 141. Vibration measurements are made by contacting the surface.

In addition, the materials, shapes, dimensions, forms, numbers, arrangement locations, and the like of the ball bearings, outer rings, inner rings, rotating shafts, holding members, measuring means, holding surfaces, recesses, and the like exemplified in the above-described embodiments are the same as those of the present embodiment. It is optional and not limited as long as the invention can be achieved.

[0062]

As described above, according to the present invention, since a plurality of recesses are provided in the holding surface of the rotating shaft, the balls are held on the holding surface through a minute gap while rotating the rotating shaft. When the bearing is held, the bearing can be reliably maintained coaxial with the rotating shaft by the dynamic pressure or static pressure generated by each concave portion. Therefore, according to this bearing inspection device, when inspecting a ball bearing, there is a possibility that the inner ring or the outer ring is fixed to be inclined with respect to the rotating shaft, or uneven wear or deformation occurs on the rotating shaft, as in the prior art. Less,
Since the ball bearing can be centered in a dry manner, it can be applied to, for example, inspection of a ball bearing used for an HDD.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram showing a first embodiment according to the present invention,
It is the principal part sectional drawing and the principal part perspective view.

FIG. 2 is an enlarged view showing a rotation shaft according to the first embodiment.

FIG. 3 is a cross-sectional view of a main part and a perspective view of a main part showing a second embodiment according to the present invention.

FIG. 4 is a cross-sectional view of a main part and a perspective view of a main part showing a third embodiment according to the present invention.

FIG. 5 is a cross-sectional view of a main part and a perspective view of a main part showing a fourth embodiment according to the present invention.

FIGS. 6A and 6B are a main part sectional view and a main part perspective view showing a fifth embodiment according to the present invention.

FIGS. 7A and 7B are a main part sectional view and a main part perspective view showing a sixth embodiment according to the present invention.

FIGS. 8A and 8B are a main part sectional view and a main part perspective view showing a seventh embodiment according to the present invention.

FIGS. 9A and 9B are a main part sectional view and a main part perspective view showing an eighth embodiment according to the present invention.

FIG. 10 is a cross-sectional view and a perspective view of a main part of a ninth embodiment according to the present invention.

FIGS. 11A and 11B are a main part sectional view and a main part perspective view showing a tenth embodiment according to the present invention.

FIG. 12 is a graph diagram relatively showing an average value of measurement results in each of the examples and comparative examples.

FIG. 13 is a schematic cross-sectional view of a principal part showing a modification according to the present invention.

FIG. 14 is a schematic sectional view showing a conventional bearing inspection device.

[Explanation of symbols]

10, 130 Bearing inspection device 11, 21, 31, 41, 51, 61, 71, 81, 91, 101, 131 Rotary shaft 13, 23, 33, 43, 53, 63, 73, 83, 93, 103 Outer peripheral surface (Holding surface) 131 inner diameter holding surface (holding surface) 14, 44, 94 Herringbone groove (recess) 24 collet groove (recess) 36 blowout hole (recess) 54, 104 groove (recess) 74, 134 Porous material (recess) ) 84 Pocket (recess) 140 Ball bearing 141 Inner ring 142 Outer ring 143 Ball 156 Holding member 157 Measuring means

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hisawa Tadokoro 1-5-50 Kugenuma Shinmei, Fujisawa-shi, Kanagawa F-term in NSK Ltd. (reference) 2G024 AC02 BA15 CA06 DA03 EA06 2G064 AA17 AB02 BA02 DD32 3J101 AA02 BA77 EA75 FA60 GA53

Claims (1)

[Claims] In order to measure vibration generated between a ball in an operating ball bearing and at least one of an outer raceway surface and an inner raceway surface, one of an outer ring and an inner ring is held and rotated. A rotating shaft to be extended, and a pressing member extending in a direction approaching from a direction away from the rotating shaft, and capable of pressing an end face of a raceway ring serving as a fixed ring of the outer ring and the inner ring, and the outer ring and A bearing inspection device comprising: a measuring unit that measures vibration by contacting a peripheral surface of a raceway ring serving as a fixed ring of the inner ring, wherein the rotation shaft has one of the outer ring and the inner ring inserted. A bearing inspection device having a holding surface for detachably holding, wherein a plurality of recesses are provided in the holding surface.