JP5015652B2 - Motor and motor assembling method - Google Patents

Description

The present invention relates to a motor and a motor assembling method , and more particularly to a technique for obtaining high strength by using an adhesive in combination when press-fitting and fixing an annular member in a hole.

It is well known to use an adhesive together in order to maintain the fixing strength when the outer peripheral surface of the annular member is press-fitted and fixed to the inner peripheral surface of the hole.
This combination is particularly effective when the annular member is thin because the press-fitting depth with the mating member is shortened.
For example, when the annular member is a bearing member of a motor used in an HDD (Hard Disk Drive) or the like, a fixing strength that can withstand external impacts is required in addition to thinning, and this method is frequently used.
As an example, Patent Document 1 describes a motor in which a thrust ring, which is a bearing member as an annular member, is press-fitted into a hub flange portion.

In general, as a method of increasing the fixing strength while reducing the thickness of the annular member as a bearing member, there are methods of increasing the press-fit margin or welding.
However, in the former case, the annular member or the press-fitted member is deformed and the performance of the motor is lowered. In the latter case, for example, when spot welding using a YAG laser or the like, the temperature is 300 ° C. to melt the member. Since it rises to near, there is a possibility that it cannot be properly fixed to a predetermined position due to a dimensional change or thermal expansion of the fitting member, and there is a possibility that spatter during welding adheres to the bearing member.
In welding, the member is rapidly cooled after the temperature is raised. Therefore, there is a possibility that the member is inclined and attached due to the contraction at the time of rapid cooling, and is not suitable for the attachment of the thrust ring (bearing).
Furthermore, it is not preferable as a method because it is likely to generate dust from welding marks and adversely affect the motor or hard disk.
For this reason, when an annular member is press-fitted and fixed as a bearing member of a motor, a method is employed in which the press-fitting is light (the press-fitting margin is small) and an adhesive is used in combination.
JP 2006-183734 A

As described above, there is a strong demand for a motor with a reduced thickness, and accordingly, the annular member constituting the bearing is also reduced in thickness.
For example, as shown in FIG. 13A, when the annular member 102 is press-fitted and fixed in the hole 101a of the press-fit member 101, a length AN (hereinafter referred to as the press-fit direction AD) that is in direct contact with the press-fit member 101. It is difficult to increase the press-in depth AN), and it is necessary to use the adhesive 103 together in order to obtain a predetermined strength.

However, since the adhesive 103 cannot sufficiently enter the range of the press-fit depth AN where the two members 101 and 102 are in direct contact with each other, the adhesive 103 does not reach the end of the press-fit portion as shown in FIG. It is applied so as to cross over both members 101 and 102 at the part.
Moreover, when it press-fits and fixes so that the end surface of both the members 101 and 102 may align as shown in FIG.13 (b), it will protrude from the adhesive agent 103 end surface, and will rise. In addition, when the viscosity of the adhesive 103 is small, the adhesive 103 may flow outward or inward as indicated by arrows in the figure before curing.
When the annular member is a bearing member, if this adhesive 103 flows to another part, there is a high possibility that a bearing locking phenomenon will be caused.

Therefore, it is extremely important that the adhesive does not protrude and does not flow to other parts.
This is particularly important for motor bearing members, but even in press-fitting when other annular members are thin, the combined adhesive does not spill out and swell up and flow to other parts. In addition, the fact that it can be fixed with high strength is strongly desired in combination with the improvement of the appearance quality.

Therefore, the problem to be solved by the present invention is that even when the annular member is thinned, the adhesive used together does not protrude and does not flow to other parts, and can be press-fitted and fixed to the press-fitted member with high strength. Another object of the present invention is to provide a method for assembling a motor using a method for press-fitting and fixing an annular member.
In addition, when the bearing is a motor, it can be press-fitted and fixed to other bearing members with high strength without the adhesive used together protruding and flowing to other parts even if it is thinned. To provide a motor.

In order to solve the above problems, the present invention has the following means 1) to 12 ).
1) a rotor including a hub having a peripheral wall portion, and a thrust ring fixed to the inner surface of the peripheral wall portion;
A stator including a base and a sleeve having a flange portion at one end and the other end fixed to the base;
A shaft fixed to the hub;
With
A motor in which the rotor is rotatably supported with respect to the stator by the shaft being pivotally supported by the sleeve;
The inner peripheral surface of the peripheral wall portion of the hub facing the outer peripheral surface of the thrust ring is, in order from the base side, a press-fitting portion that directly contacts the thrust ring, and a facing portion that faces the outer peripheral surface of the thrust ring with a gap. And having
The facing portion includes a first facing portion from the press-fit portion to a top portion having a minimum diameter among the facing portions, and a second facing portion on the opposite side of the press-fit portion with respect to the top portion,
An outer peripheral surface of the thrust ring and an inner peripheral surface of the peripheral wall portion are fixed by an adhesive from the first opposing portion to the second opposing portion.
2) The gap between the first facing portion and the thrust ring is filled with the adhesive, and the gap between the second facing portion and the thrust ring is filled with the adhesive at least halfway. In the motor according to 1), the adhesive of the first facing portion and the adhesive of the second facing portion are continuous.
3) The gap between the second facing portion and the outer circumferential surface of the thrust ring is narrower than the gap between the first facing portion and the outer circumferential surface of the thrust ring. It is a motor.
4) The motor according to any one of 1) to 3), wherein the thrust ring is made of a material having a thermal expansion coefficient larger than that of the hub.
5) The motor according to any one of 1) to 4), wherein the adhesive is a thermosetting adhesive.
6) The motor according to any one of 1) to 5), wherein a leading surface of the thrust ring in the insertion direction is in contact with the hub.
7) An outer peripheral portion of the sleeve is fixed to the base via a housing, and a thrust dynamic pressure bearing is formed in which the thrust ring is sandwiched between the flange portion and an end portion of the housing. The motor according to any one of 1) to 6), wherein a lubricant is filled in a gap and a gap between the thrust ring and the sleeve.
8) The motor according to any one of 1) to 7), wherein the top is formed at an axial center of the facing portion.
9) In any one of 1) to 7), a concave portion is formed on the inner peripheral surface of the peripheral wall portion of the hub from the second facing portion to the side opposite to the press-fitting portion. It is a motor of description.
10) The method for assembling a motor according to any one of 1) to 9),
An adhesive application step of applying the adhesive to the first facing portion on the inner peripheral surface of the hub in advance;
Press-fitting the thrust ring into the press-fitting portion of the hub;
A heat curing step of heating and curing the adhesive;
A method for assembling the motor.
11) In the heat curing step, the adhesive applied to the first facing portion is changed to the second facing portion by changing the distance between the facing portion and the thrust ring due to thermal expansion deformation of the thrust ring. The method for assembling a motor according to 10), wherein the temperature and time are adjusted so as to be spread and cured.
12) The adhesive applied to the first facing portion is spread and cured to the second facing portion by a capillary phenomenon generated between the facing portion and the thrust ring. 10) or 11 Is a method of assembling the motor.

According to the present invention, in the motor assembling method , even if the annular member is thinned, the combined adhesive does not protrude and does not flow to other parts, and can be press-fitted and fixed with high strength. Play.
Also, when the annular member is a motor bearing member, even if it is thinned, the combined adhesive does not protrude and does not flow to other parts, and it is press-fitted and fixed to other bearing members with high strength. it is, that Sosu the effect that.

Embodiments of the present invention will be described with reference to FIGS. 1 to 12 by the preferred embodiment.

The motor 50 of the embodiment is a motor that is mounted on an HDD and drives a hard disk.
As shown in FIG. 1, the motor 50 has a rotor R, a stator S, and a shaft 1 fixed to the rotor R. The shaft 1 is a radial and thrust dynamic pressure bearing RB1, RB2, SB1. , SB2, and the rotor R is rotatably supported with respect to the stator S.

  More specifically, the stator S includes a motor base 2 having a through hole 2b having a rising portion 2a around it, a cylindrical housing 3 fixed in the through hole 2b, and the housing 3 A sleeve 4 having a flange portion 4a fixed to the inner peripheral portion and extending outwardly on one end side; a core 6 fixed to the outer peripheral portion 2c of the rising portion 2a in the motor base 2 and wound with a coil 5; And an FPC (flexible printed wiring board) 7 having a wiring pattern to which the lead 5a of the coil 5 is connected.

  On the other hand, the rotor R has a flat round plate-like base portion 8b having a through hole 8a, a peripheral wall portion 8c provided around the base portion 8b, and an inner peripheral wall portion provided on the inner diameter side of the peripheral wall portion 8c so as to face the peripheral wall portion 8c. 8d and a hub 8 having a flange portion 8e extending outward from the tip of the peripheral wall portion 8c, a ring-shaped magnet 9 fixed to the inner surface of the peripheral wall portion 8c, and fixed to the inner peripheral portion of the inner peripheral wall portion 8d And a thrust ring 10 that is an annular member.

The shaft 1 is press-fitted and fixed in the through hole 8 a of the hub 8, and the shaft 1 is inserted into the through hole 4 b of the sleeve 4.
A lubricant 12 is filled between the shaft 1 and the inner peripheral surface 4b1 of the through hole 4b.

Further, referring to FIG. 2 which is an enlarged view of the vicinity of the thrust ring 10, the shaft 1 is inserted into the sleeve 4, and the flange portion 4a of the sleeve 4 has its one end face 4a1 (on the upper side of FIG. 2). Surface) is opposed to the inner surface 8f of the hub 8, and the other end surface 4a2 of the flange portion 4a is opposed to one end surface (the upper surface in FIG. 2) 10a of the thrust ring 10.
The one end face 10a abuts a step 8g formed by protruding a part of the inner face 8f of the hub 8 downward in FIG. 2, and the position of the thrust ring 10 in the axis CL direction is defined. .

Returning to FIG. 1, a pair of dynamic pressure grooves 11 are formed in the inner peripheral surface 4 b of the sleeve 4 so as to be spaced apart in the direction of the axis CL. The radial dynamic pressure bearing portions RB1 and RB2 are constituted by 1a and the lubricant 12.
On the other hand, a seal plate 13 is attached to the end portion 3 d of the housing 3 so as to cover the end surface 1 b of the shaft 1 and the end surface 4 c of the sleeve 4.

As shown in FIG. 2, thrust dynamic pressure grooves 14a and 14b are formed in the thrust ring 10 in a range of the one end face 10a facing the flange portion 4a and the other end face 10b, respectively.
The thrust dynamic pressure groove 14a, the other end face 4a2 of the flange portion 4a opposite to the thrust dynamic pressure groove 14a, and the lubricant 12 filled therebetween constitute the thrust dynamic pressure bearing portion SB1, and the thrust dynamic pressure groove 14b. The thrust dynamic pressure bearing portion SB2 is configured by the one end surface 3a of the housing 3 opposed to the housing 3 and the lubricant 12 filled therebetween.

  The lubricant 12 is located between the seal plate 13 and the end surface 1b of the shaft 1 as the innermost part, and between the outer peripheral surface 1a of the shaft 1 and the inner peripheral surface 4b1 of the sleeve 4 (of course, the radial dynamic pressure bearing portions RB1, RB2). Between the one end surface 4a1 of the sleeve 4 and the inner surface 8f of the hub 8, between the thrust dynamic pressure bearing portion SB1 and the inner peripheral surface 10c of the thrust ring 10, and the facing surface 4d of the sleeve 4 facing this, It fills in the path | route which reaches the taper seal part TS which the liquid level 12a is located and opens outside through the thrust dynamic pressure bearing part SB2.

The taper seal portion TS has a smaller diameter as the distance from the thrust dynamic pressure bearing portion SB2 increases, and the outer peripheral surface 3b of the housing 3 is formed to have a smaller diameter as the distance from the thrust dynamic pressure bearing portion SB2 increases. 3 and the inner peripheral surface 8d1 of the inner peripheral wall portion 8d formed so as to increase the distance from the outer peripheral surface 3b.
Since the taper seal portion TS generates a centrifugal force that causes the lubricant 12 to be directed toward the back side as the rotor R rotates, leakage of the lubricant 12 to the outside is prevented.

With the above configuration, the motor 50 is rotationally driven by energizing the coil 5 from the outside. At this time, the lubricant is applied to the radial dynamic pressure bearing portions RB1 and RB2 and the thrust dynamic pressure bearing portions SB1 and SB2. A dynamic pressure is generated in the rotor 12, and the rotor R rotates in a state of floating with respect to the stator S.
In the motor 50, a hard disk (not shown) is placed on the flange portion 8e of the hub 8, and is further fixed by a clamper (not shown).

  By the way, the thrust ring 10 is fixed to the inner peripheral surface 8d1 of the inner peripheral wall portion 8d of the hub 8. In the motor 50 according to the embodiment, this fixing is performed by the combined use of press-fitting and an adhesive. Hereinafter, the press-fitting and fixing method and structure will be described in detail.

As described above, the thrust ring 10 is formed with the thrust dynamic pressure grooves 14a and 14b, and after assembly, the gap with the opposing surface facing these is extremely small as is well known. Yes.
Therefore, in order to fully exhibit the performance as a dynamic pressure bearing, the deformation of the thrust ring 10 must be avoided as much as possible. Therefore, the press-fitting into the hub 8 is performed with a considerably small margin for press-fitting. Yes. For example, the press-fit margin is about 5 μm with respect to the outer diameter φ6.6 mm of the thrust ring 10.

Further, as shown in FIG. 3, the motor 50 of the embodiment includes a press-fit portion ANB that is in direct contact with the thrust ring 10 on the inner peripheral surface 8d1 of the inner peripheral wall portion 8d of the hub 8, and a deeper position than the press-fit portion ANB. A proximity facing portion KTB that is formed on the side (the upper side in FIG. 3) and faces the outer peripheral surface 10d of the thrust ring 10 with a slight gap is provided.
The proximity facing portion KTB has a top portion TB having the smallest diameter at the central portion in the direction of the axis CL, and is formed so as to slightly protrude inward.

As a specific numerical example, the distance between the outer peripheral surface 10d of the thrust ring 10 and the top portion TB is d1, and the distance between the outer peripheral surface 10d and the parts KTB1 and KTB2 that are the farthest from the axis CL of the adjacent facing portion KTB is If d2,
d1 = 60 μm
d2 = 70 μm
It is. For this example, FIG. 3 is exaggerated for ease of understanding.

  The press-fit portion ANB and the taper seal portion are connected by an inclined surface KM.

  Here, when the adjacent facing portion KTB is divided into a first facing portion KT1 on the side close to the press-fit portion ANB and a second facing portion KT2 on the far side with the top portion TB as a boundary, at least the first facing portion KT1. The adhesive 17 is hardened and filled in the middle or the whole of the second facing portion KT2 beyond the top TB.

Here, the material of the thrust ring 10 that is an annular member and the hub 8 that is a press-fitted member is selected so that the thrust ring 10 is larger than the hub 8 in terms of the thermal expansion coefficient of each material. ing.
Specific examples include the following combinations.
Thrust ring: SUS303 (Coefficient of thermal expansion: 17.2 × 10 ⁻⁶ / ° C.)
Hub: SUS430 (Coefficient of thermal expansion: 10.6 × 10 ⁻⁶ / ° C.)

Thus, by setting the thermal expansion coefficient so that the inner thrust ring 10 is larger, high adhesive strength can be stably obtained in press-fitting and fixing the thrust ring 10 to the hub 2.
This will be described below along the motor assembly process.

<Assembly of bearing unit>
Assembly of the bearing unit will be described with reference to FIGS. 4 and 5.

First, in FIG. 4, the thrust ring 10 is attached to the outer peripheral portion from the end surface 4 c side of the sleeve 4.
Next, the epoxy adhesive 15 is applied to the outer peripheral surface near the end surface 4 c of the sleeve 4 in a circumferential manner, and the housing 3 is mounted. Since the gap between the inner diameter of the housing 3 and the outer diameter of the sleeve 4 is set to be extremely small, the epoxy adhesive 15 is spread over almost the entire inner peripheral surface 3 c of the housing 3.
The seal plate 13 is placed on the end 3d of the housing 3, and the epoxy adhesive 16 is applied to the boundary between the two (see FIG. 5). And it heats in this state and hardens an epoxy adhesive.
As described above, the bearing unit JU is assembled.

<Assembly of rotor>
Next, the assembly of the rotor R will be described.

First, in a separate process from the assembly of the bearing unit, as shown in FIG. 6, the shaft 1 is press-fitted into the through hole 8a of the hub 8 to obtain a hub-shaft assembly HST shown in FIG. In the press-fitting, an epoxy adhesive may be used in combination.
The bearing unit JU is attached to the hub-shaft assembly HST. This attachment process is performed at room temperature.
Specifically, as shown in FIGS. 8A and 8B, the adhesive 17 is applied over the entire circumference of the inner peripheral surface 8d1 of the hub 8 on the press-fit portion ANB side of the first facing portion KT1 in advance. Keep it.
The adhesive 17 can be an epoxy heat curing type, and is, for example, an optical adhesive 353ND (viscosity: 5000 cPs) manufactured by Epoxy Technology.
At this viscosity, the adhesive 17 is applied so as to rise to the inside of the press-fit portion ANB.

Thereafter, the sleeve 4 of the bearing unit JU is inserted into the shaft 1.
Insertion is further advanced, and the outer peripheral surface 10d of the thrust ring 10 is pushed into the press-fitting portion of the hub 8 until the one end surface 10a of the thrust ring 10 (the leading surface of the thrust ring 10 in the insertion direction) comes into contact with the step 8g of the hub 8 . Press fit into the ANB (see FIG. 9).
Along with this press-fitting, the adhesive 17 applied in advance is scraped off and extended toward the top TB from the press-in part ANB, and is extended between the first facing part KT1 and the thrust ring 10 . The gap is almost filled. At that time, there is no problem even if a part of the adhesive 17 gets over the top TB.

FIG. 10 shows the state of the adhesive 17 when the press-fitting is completed.
In FIG. 10, the adhesive 17 is filled in the first facing portion KT1, and a part of the adhesive 17 may penetrate the second facing portion KT2 side beyond the top portion TB.

Next, in order to cure the adhesive 17, it is heated and left at a high temperature.
This heat curing process is 1 hour or more at the adhesive 353ND and 90 ° C. described above.

As described above, the thrust ring 10 and the hub 4 are selected so that the thermal expansion coefficient of the thrust ring 10 is larger.
Therefore, the gap between the outer peripheral surface 10d of the thrust ring 10 and the close facing portion KTB of the hub 8 is narrower than that at normal temperature when left at high temperature.
Therefore, the capillary action at the top portion TB and the vicinity thereof is also added, and the adhesive 17 of the first facing portion KT1 moves to the second facing portion KT2 side beyond the top portion TB, and the filling range of the adhesive 17, that is, the thrust ring. 10 and the contact range with the hub 8 is increased.
Since the adhesive 17 is cured in a state where the contact range is increased, the adhesion area is increased and the fixing strength between the thrust ring 10 and the hub 8 is improved.

In particular, in the embodiment, by providing the top portion TB, the adhesive 17 is accumulated on the first facing portion KT1 side in the application of the adhesive 17 at room temperature, and the filling range is obtained in the heat curing step after press-fitting. To spread.
As a result, it is possible to prevent the applied adhesive 17 from protruding outside the proximity facing portion KTB due to the press-fitting, and since this protrusion does not occur, the coating amount can be minimized.
Therefore, it is possible to prevent the occurrence of a bearing failure due to the sticking out of the adhesive 17 and to prevent the adhesive from being wasted.

  The increase in the adhesion area will be schematically described with reference to FIG. This figure is a diagram showing a portion filled with the adhesive 17 at a normal temperature before the heat curing step and a temperature rise in the middle of the step. Has been granted.

FIG. 11A shows a state in which a predetermined amount of the adhesive 17 is applied to the gap between the proximate facing portion KTB without the top portion TB and the thrust plate 10.
The length in the axis CL direction of the contact range where the adhesive 17 is in contact with the thrust ring 10 and the hub 8 is L17a.
Further, the distance between the adjacent facing portion KTB and the outer peripheral surface 10d of the thrust ring 10 is dm1a.

FIG. 11 (b) shows a state at an elevated temperature.
As described above, the distance dm1a is shortened to be the distance dm1b due to the difference in thermal expansion coefficient. Thereby, the adhesive 17 in the range V1 indicated by hatching in FIG. 11A shifts to the range V2 indicated by cross-hatching, and the contact range of the adhesive 17 is expanded to L17b.

On the other hand, FIG.11 (c) is a schematic diagram of the Example in which the top part TB was provided.
In this case, the length in the axis CL direction of the contact range where the adhesive 17 is in contact with the thrust ring 10 and the hub is L17a.
Further, the proximity facing portion KTB has two regions of a second facing portion TK2 including a first facing portion KT1 and a top portion TB.
The distance between the first facing portion KT1 and the outer peripheral surface 10d of the thrust ring 10 is dm1a.
The top portion TB and the second facing portion are shown as having the same diameter with respect to the axis CL for easy understanding, and the gap with the outer peripheral surface 10d is dm2a .
Further, as an ideal form, it is assumed that the adhesive 17 is almost filled in the gap between the first facing portion KT1 and the outer peripheral surface 10d.

FIG.11 (d) has shown the state under the temperature rise of FIG.11 (c).
In this case as well, the distance dm1a is reduced to a distance dm1b due to the difference in thermal expansion coefficient. Accordingly, the adhesive 17 in the range V1 indicated by hatching in FIG. 11D shifts to the range V3 indicated by cross-hatching, and the contact range of the adhesive 17 is expanded to L17d.
Here, since the top portion TB and the second facing portion KT that are closer to the outer peripheral surface 10d are provided in the portion where the adhesive moves, the contact range of the adhesive 17 in the range V1 is larger than that of L17b. Long L17d.
Since L17d is V1 = L17a × (dm1a−dm1b),
L17d = V1 / dm2b.
Therefore, by providing the top portion TB and transferring the adhesive 17 corresponding to the gap narrowed by the temperature rise in the first facing portion KT1 to the gap between the top portion TB and the outer peripheral surface 10d, the bonding range can be widened. it can.

To explain an example with specific numerical values,
・ Outer diameter of thrust ring: 6.595mm
-Inner diameter of the first facing portion KT1: 6.655 mm
Dm1a = 60 μm, dm2a = 15 μm, L17a = 0.2 mm
Thrust ring: SUS303 (Coefficient of thermal expansion: 17.2 × 10 ⁻⁶ / ° C.)
Hub: SUS430 (Coefficient of thermal expansion: 10.6 × 10 ⁻⁶ / ° C.)
If the temperature is raised from 20 ° C. at normal temperature to 90 ° C. during the curing process,
The radius of the outer peripheral surface 10d of the thrust ring is
(6.595 / 2) × 17.2 × 10 ⁻⁶ × 70 = 0.040 mm Increase,
3.302 mm.
The inner diameter of the first facing portion KT1 is
(6.655 / 2) × 10.6 × 10 ⁻⁶ × 70 = 0.0027 mm
3. 330 mm.

Therefore, the gap between the two is reduced by 0.0040−0.0027 = 0.0014 mm to 58.7 μm (= dm1b).
Here, since L17a is 0.2 mm,
When there is no top TB and second opposing part KT2,
0.2 * 0.0013 / (3.330-3.302) = 0.0093mm
The axial contact range of the adhesive is expanded.

On the other hand, if the top portion TB and the second facing portion KT2 are provided, and the distance dm2b from the outer peripheral surface 10d is set to 0.015 mm at the time of temperature rise, the contact range in the axial CL direction of the adhesive 17 is
ΔL = 0.2 × 0.0013 / 0.015 = 0.0173 mm Enlarge.

Accordingly, the contact range in the axial CL direction when the top portion TB and the second facing portion KT2 are provided is compared with the case where the top portion TB and the second facing portion KT2 are not provided.
(0.2 + 0.0173) / (0.2 + 0.0093) = 1.038 times That is, it is understood that the magnification is 3.8%.

Furthermore, the contact range of the adhesive 17 can be further expanded by the capillary phenomenon shown by the following (formula 1) in the minute gap. That is,
Δh = 2σ · COSθ / ρg (r ₀ −r ₁ ) (Formula 1)
Where Δh is the amount of change in the liquid level, σ is the surface tension coefficient, θ is the contact angle, ρ is the adhesive density, r _{0 is the} diameter of the top or second facing portion KT2, and r ₁ is the diameter of the outer peripheral surface 10d.

となる。
すなわち、９０℃における表面張力による接着剤界面の上昇距離は、接着剤充填時（常温下）における表面張力による界面の上昇距離の１．５倍に増加する。 As can be seen from this equation, the smaller the distance dm2b in FIG. 11c, indicated by r ₀ -r ₁ , the more the liquid level rises, so the adhesive range in the axis CL direction is further expanded to improve the strength. be able to.
To explain with specific numerical examples, as described above, thrust ring: SUS303 (thermal expansion coefficient: 17.2 × 10 ⁻⁶ / ° C.), hub: SUS430 (thermal expansion coefficient: 10.6 × 10 ⁻⁶ / When the gap between the fitting parts is reduced from 5 μm to 3 μm at 90 ° C., for example, from Equation (1),

It becomes.
That is, the rising distance of the adhesive interface due to the surface tension at 90 ° C. increases to 1.5 times the rising distance of the interface due to the surface tension when the adhesive is filled (at room temperature).

  Since the heat-curing epoxy adhesive usually has a certain degree of elasticity after curing, stress is applied to the thrust ring 10 and the hub 8 in a state where the adhesion area is increased even if the temperature is lowered to room temperature after being cured in the heat-curing process. Adhesive strength with high strength is exhibited without loading.

  In the press-fitting and fixing method of the above-described embodiment, in the press-fitting and fixing of the thrust ring 10 that is a press-fitting member and the hub 8 that is a press-fitted member, the contact area of the adhesive is increased with the temperature increase in the heat curing process of the adhesive. The first opposed portion KT1 is increased by utilizing the shape of the inner peripheral surface of the adhesive-filled portion and the capillary phenomenon, and depends on the curing temperature condition of the adhesive used and the material of the thrust ring 10 and hub 8 used. , The second facing portion KT2, the distances d1, d2, and the like can be set as appropriate.

The top portion TB is not limited to a point (line in the circumferential direction) in the cross section as in the embodiment, but may be formed to be a line (surface in the circumferential direction) in the cross section.
FIG. 12 shows an example of this. The types of each member and adhesive are as described in the examples.

FIG. 12 is a cross-sectional view showing a state where an annular member 72 as a press-fitting member is press-fitted and fixed from the AD direction in combination with an adhesive 73 into the through hole 71a of the press-fitted member 71.
In the inner peripheral surface 71b of the through hole 71a, in a range facing the outer peripheral surface 72a of the annular member 72, from the opening side of the through hole 71a, a press-fit portion ANB and an annular member that are press-fitted in direct contact with the annular member 82 The first opposed portion KT1 and the outer peripheral surface 72a facing each other with an inner peripheral surface separated by a distance d2 from the outer peripheral surface 72a of 72 have an opposing surface separated by a distance d1 shorter than the distance d2. Thus, the opposing second opposing portion KT2 and the concave portion KT3 that is removed from the second opposing portion KT2 by the depth d3 are formed.

As explained in the embodiment, before the annular member 72 is press-fitted, the minimum necessary amount of adhesive 73 is applied to the press-fitting portion ANB side of the first facing portion KT1, and after the annular member 72 is press-fitted, the temperature is raised and bonded. The agent is cured.
As described above, due to the difference in thermal expansion coefficient, the gap between the two members decreases and the capillary phenomenon is exerted by the gap that is reduced and narrowed, so that the adhesive 73 accumulated in the first facing portion KT1 is the second The counter part KT2 is also spread and filled, and is cured in that state.
Accordingly, as shown in FIG. 12 , a wide range is an adhesive range from the first opposing portion KT1 to the second opposing portion KT3, and the fixing strength is further improved, and the adhesive 73 flows out to the outside by the concave portion KT3. Is prevented.

As described in the embodiment, only a fixed strength of about 10 kgf can be obtained only by press-fitting a member having a diameter of 6.6 mm into the press-fitted member at a pressure of 5 μm. By applying 4 mg or more, it is possible to ensure a fixed strength of 50 kgf or more, which is an indication of market demand strength.
According to the press-fit fixing structure of the embodiment, the strength can be further improved by about 4% even when the same amount of adhesive is used.
Further, it is difficult for the adhesive to protrude from the predetermined application range by the press-fitting operation, and it is possible to prevent other parts from being adversely affected.

  The embodiment of the present invention is not limited to the configuration and procedure described above, and it goes without saying that modifications may be made without departing from the scope of the present invention.

It is a half sectional view for explaining the motor to which the example in the press fit fixing method of the annular member of the present invention was applied. It is a principal part enlarged view for demonstrating the motor of FIG. It is a principal part enlarged view for demonstrating in detail the motor of FIG. It is a 1st figure for demonstrating the assembly process in the Example of the motor of this invention. It is a 2nd figure for demonstrating the assembly process in the Example of the motor of this invention. It is a 3rd figure for demonstrating the assembly process in the Example of the motor of this invention. It is a 4th figure for demonstrating the assembly process in the Example of the motor of this invention. It is a 5th figure for demonstrating the assembly process in the Example of the motor of this invention. It is a 6th figure for demonstrating the assembly process in the Example of the motor of this invention. It is a 7th figure for demonstrating the assembly process in the Example of the motor of this invention. It is a schematic diagram for demonstrating the Example of the fixing method of the annular member of this invention. It is sectional drawing for demonstrating the Example of the fixing method of the annular member of this invention. It is a figure for demonstrating the fixing method of the conventional annular member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shaft 1a Outer surface 1b End surface 2 Motor base 3 Housing 3a One end surface 3b Outer surface 3c Inner surface 3d End 4 Sleeve 4a Flange part 4a1 One end surface 4a2 Other end surface 4b Through-hole 4b1 Inner surface 4c End surface 4d Opposite surface 5 Coil 6 Core 7 FPC
8 hub 8a through hole 8b base 8c peripheral wall 8d inner peripheral wall 8d1 inner peripheral surface 8e flange 8f inner surface 8g step 9 magnet 10 thrust ring 10a one end surface 10b other end surface 10c inner peripheral surface 10d outer peripheral surface 11 radial dynamic pressure groove 12 Lubricant 12a Liquid level 13 Seal plates 14a and 14b Thrust dynamic pressure grooves 15 and 16 Epoxy adhesive 17 Adhesive 50 Motor ANB Press-fit portion CL Shaft d1, Clearance HST Hub-shaft assembly JU Bearing unit KM Inclined surface KTB Proximity facing Part R Rotor RB1, RB2 Radial dynamic pressure bearing part S Stator SB1, SB2 Thrust dynamic pressure bearing part TB Top TS Taper seal part

Claims (12)

A rotor including a hub having a peripheral wall portion, and a thrust ring fixed to the inner surface of the peripheral wall portion;
A stator comprising a base, a sleeve fixed to the front SL base and,
A shaft fixed to the hub;
A lubricant interposed between at least the sleeve and the thrust ring;
With
A motor in which the rotor is rotatably supported with respect to the stator by the shaft being pivotally supported by the sleeve;
The hub, wherein the inner peripheral surface of the outer peripheral surface and you opposed peripheral wall portions of the thrust ring, in order from the base side, a press-fit portion in direct contact with the thrust ring, with the outer peripheral surface and the gap of the thrust ring facing portions facing, as well as have a, has an end face head surfaces of the insertion direction of the thrust ring to form a contact with the contact portion to the hub,
The facing portion includes a first facing portion from the press-fit portion to a top portion having a minimum diameter among the facing portions, and a second facing portion on the opposite side of the press-fit portion with respect to the top portion,
The outer peripheral surface of the thrust ring and the inner peripheral surface of the peripheral wall portion are fixed with an adhesive from the first opposing portion to the second opposing portion ,
A space formed by the outer peripheral surface of the thrust ring and the inner peripheral surface of the peripheral wall portion is closed by the press-fit portion and the contact portion, and is fixed with an adhesive from the first opposing portion to the second opposing portion. A motor characterized by being made. In the gap between the thrust ring gap and the previous SL second opposing portion and said thrust ring and said first opposing portion is interposed previous SL adhesive, wherein said adhesive of said first facing portion The adhesive that is continuous with the adhesive of the second facing portion and that is formed by the outer peripheral surface of the thrust ring and the inner peripheral surface of the peripheral wall portion is bonded without the adhesive interposed on the opposite side of the press-fit portion. The motor according to claim 1, further comprising an agent non-intervening region .   3. The motor according to claim 1, wherein a gap between the second facing portion and the outer circumferential surface of the thrust ring is narrower than a gap between the first facing portion and the outer circumferential surface of the thrust ring.   4. The motor according to claim 1, wherein the thrust ring is formed of a material having a thermal expansion coefficient larger than that of the hub. 5.   The motor according to any one of claims 1 to 4, wherein the adhesive is a thermosetting adhesive.   The sleeve has a flange portion on one end side of the hub side,
  The said thrust ring is arrange | positioned in the position where the end surface by the side of the said hub of the said thrust ring opposes the end surface by the side of the said base of the said flange part in any one of the Claims 1-5. The motor according to claim 1. An outer peripheral portion of the sleeve is fixed to the base via a housing, and a thrust dynamic pressure bearing is formed in which the thrust ring is sandwiched between the flange portion and an end portion of the housing, and a gap between the thrust dynamic pressure bearing and The motor according to claim 6 , wherein a gap between the thrust ring and the sleeve is filled with a lubricant.   The motor according to any one of claims 1 to 7, wherein the top portion is formed at an axial center of the facing portion.   8. The recess according to claim 1, wherein a concave portion is formed on the inner peripheral surface of the peripheral wall portion of the hub from the second facing portion on a side opposite to the press-fitting portion. The motor described. A method for assembling a motor according to any one of claims 1 to 9,
An adhesive application step of applying the adhesive to the first facing portion on the inner peripheral surface of the hub in advance;
Press-fitting the thrust ring into the press-fitting portion of the hub;
A heat curing step of heating and curing the adhesive;
A method for assembling a motor, comprising:   In the heat curing step, the adhesive applied to the first facing portion is expanded to the second facing portion due to a change in the distance between the facing portion and the thrust ring due to thermal expansion deformation of the thrust ring. The method of assembling a motor according to claim 10, wherein the method is performed by adjusting the temperature and time so as to be cured.   11. The adhesive applied to the first facing portion is spread and hardened to the second facing portion by a capillary phenomenon generated between the facing portion and the thrust ring. 11. A method for assembling the motor according to 11.

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