JP4174657B2 - Deep groove ball bearing and fan coupling device - Google Patents

Description

[0001]
The present invention relates to a deep groove ball bearing that is suitably incorporated in a fan coupling device or the like, and more particularly to a deep groove ball bearing and a fan coupling device that are effective when the operating temperature is wide.
BACKGROUND OF THE INVENTION
[0002]
[Prior art]
In order to cool the engine, a cooling fan is disposed so as to face the engine, and a fan coupling device is used particularly in an FR vehicle. The fan coupling device has a housing in which a viscous fluid is stored inside and a fan for blowing air is provided on an outer peripheral portion. The housing is connected to a rotor provided on a drive shaft connected to the engine via a deep groove ball bearing. A labyrinth is provided on the relative surface of the housing and the rotor, and viscous fluid enters the labyrinth. The driving torque from the engine is first transmitted to the rotor, and is transmitted from the rotor to the housing and the fan for blowing air using the viscous resistance of the viscous fluid. The valve member that opens and closes according to the ambient temperature controls the amount of torque transmitted by the viscous fluid. When the engine temperature is low, the fan rotates at a low speed. When the engine temperature is high, the fan rotates at a high speed. The air is blown to the engine temperature at that time.
[0003]
In general, in a bearing device such as the above-described fan coupling device, a housing made of an aluminum alloy tends to be used in order to reduce the weight of the housing and improve the heat dissipation with the increase in the speed of the drive shaft.
On the other hand, the drive shaft is made of cast iron.
[0004]
[Problems to be solved by the invention]
In the conventional fan coupling device, there is almost no difference in the linear expansion coefficient of the material between the drive shaft and the inner ring, but there is a large difference in the linear expansion coefficient of the material between the aluminum housing and the outer ring. Therefore, in the high temperature range, the aluminum housing tends to expand more than the outer ring, and the interference between the aluminum housing and the outer ring decreases. Further, the temperature further increases due to the shear resistance of the viscous fluid, and may reach 200 ° C. or higher. At such a high temperature, the interference between the aluminum housing and the outer ring disappears, and creep of the outer ring may occur. In the worst case, the viscous fluid leaks and the fan rotation cannot be controlled properly.
Thus, in the case where the operating temperature is very high, the interference at the fitting portion at room temperature is increased in order to ensure the interference in the high temperature range.
[0005]
On the other hand, an automobile part such as a fan coupling device may be used at a low temperature, and may be used in an atmosphere of, for example, about −40 ° C. In this case, contrary to the above, since the aluminum housing tends to contract more than the bearing outer ring, the bearing outer ring is forcibly compressed.
In order to prevent labyrinth interference, the bearing effective gap at high temperatures may be set small in order to keep the bearing gap small at high temperatures (region where the interference between the housing and the outer ring is small). In this case, for example, at a low temperature of −40 ° C., the bearing effective gap becomes −30 μm to −50 μm. In addition to this, the fluidity of the bearing lubricant also deteriorates at low temperatures, making it difficult for the lubricant to enter between the balls and the raceway surface, resulting in premature surface roughness and wear, and problems such as abnormal noise and backlash. Sometimes. In the worst case, seizure can occur, which can lead to a malfunction of the fan coupling device.
[0006]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a deep groove ball bearing and a fan coupling device that can operate satisfactorily over a long period of time even in a wide range of operating temperatures.
[0007]
[Means for Solving the Problems]
The object of the present invention is achieved by the following configurations.
(1) An inner ring having an inner ring raceway on an outer diameter surface, an outer ring having an outer ring raceway on an inner diameter surface, and a plurality of balls arranged between the inner and outer ring raceways are incorporated between a shaft and an outer member. In deep groove ball bearings,
A circumferential groove is provided on the outer diameter surface of the outer ring to allow a variation in interference with the outer member, and the outer ring raceway has a central curved surface in a cross-sectional view before assembly to the outer member, and deep groove ball bearing, characterized in that the said central curved surfaces disposed on either side of the central curved surface and a side curved surface radius of curvature greater than the inner curved surface Ri of curvature center Do different.
(2) The deep groove ball bearing according to (1), wherein a buffer material is provided in the circumferential groove.
(3) the axial length of the mating surfaces between the outer ring and the outer member is, extending in the axial direction on the outer ring to be longer than the axial length of the mating surfaces between the said inner ring shaft The deep groove ball bearing according to claim 1, wherein an extending portion is provided.
(4) A fan coupling device in which the deep groove ball bearing according to any one of (1) to (3) is incorporated .
[0008]
In the above configuration, the bearing when the interference on the fitting surface fluctuates due to a change in temperature due to the circumferential groove provided on the outer diameter surface of the outer ring which is a fitting surface with an outer member such as a housing. The fluctuation of the gap can be absorbed and the fluctuation of the outer ring raceway diameter can be prevented. Even when the difference in coefficient of linear expansion between the outer member and the outer ring is large, fluctuations in the bearing clearance can be sufficiently absorbed, and a bearing having robustness against temperature changes can be obtained. Furthermore, it is possible to prevent problems such as a decrease in bearing life and occurrence of abnormal noise.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the drawings. Prior to the description of the embodiment, a reference example of the present invention will be described with reference to FIGS. In the fan coupling device 1 shown in FIG. 1, a deep groove ball bearing (hereinafter also simply referred to as “bearing”) 10 is externally fitted to a drive shaft 2, and a housing 3 is externally fitted to the bearing 10. A fan 3 a is provided on the outer periphery of the housing 3. A rotor 4 is externally fitted to the drive shaft 2 adjacent to the bearing 10. The drive shaft 2, the inner ring of the bearing 10, and the rotor 4 rotate integrally. A viscous fluid storage space 8 and a labyrinth 6 communicating with the storage space 8 are formed between the housing 3 and the rotor 4. In the storage space 8, silicon oil or the like is stored as a viscous fluid.
[0010]
A front cover 5 is provided on the front end side (left side in the figure) of the drive shaft 2. A bimetal 7 is connected to the front cover 5. When the bimetal 7 is deformed along with the temperature change, the valve member fixed to the bimetal 7 moves to control the torque transmission amount by the viscous fluid.
[0011]
The structure of the bearing 10 will be described in detail with reference to FIG. The bearing 10 includes an inner ring 11 having an inner ring raceway 11a on an outer diameter surface, an outer ring 12 having an outer ring raceway 12a on an inner diameter surface, and a plurality of balls 13 arranged between the inner and outer ring raceways 11a and 12a. The plurality of balls 13 are held by a cage (here, a corrugated press cage) 14 so as to roll freely at intervals in the circumferential direction.
[0012]
A circumferential groove 12 b is provided on the outer diameter surface of the outer ring 12 to allow fluctuations in interference with the housing 3. The axial dimension (groove width) X ′ of the circumferential groove 12b can be set equal to or narrower than the axial dimension X of the outer ring raceway 12a. X ′ is preferably set to 0.5X to 1.0X.
The radial dimension (depth) A of the circumferential groove 12 b is preferably equal to or greater than the maximum value of the radial interference in the operating temperature range of the bearing 10 and the housing 3. For example, when the interference between the outer diameter of the outer ring 12 and the inner diameter of the housing 3 is in the range of 0.100 mm to 0.150 mm at low temperatures, the depth A of the circumferential groove 12b is preferably (0.150 / 2) mm or more. .
[0013]
In this reference example , the outer ring raceway 12a has a single curved surface in sectional view, and the curved surface has a single radius of curvature re.
[0014]
A pair of sealing members 15, 15 are provided with the ball 13 interposed therebetween. In this reference example , the outer peripheral portions of the seal members 15 and 15 are fixed to both axial ends of the inner surface of the outer ring 12, and the inner peripheral portions of the seal members 15 and 15 are in contact with the outer surface of the inner ring 11. A lubricant such as grease is sealed in the bearing space sealed by the seal members 15 and 15.
Not only the contact-type seal member 15 but also a non-contact type seal member can be used. It is also possible to use oil as the lubricant.
[0015]
The operation when the bearing 10 as described above is assembled between the drive shaft and the housing will be described with reference to FIG.
Of the outer diameter surface of the outer ring 12, portions on both sides of the circumferential groove 12 b serve as mating surfaces with the housing 3. The interference increases when the temperature is low, and the fitting surfaces receive the compression force P from the housing 3. At that time, both axial ends of the outer ring 12 contract together with the housing 3, and the outer ring 12 bends in a direction to reduce the groove curvature radius re of the outer ring raceway 12a as indicated by an arrow R in the figure. That is, the outer ring 12 bends so that the outer diameter surface is convex toward the outer peripheral side.
[0016]
In the figure, the ball diameter is indicated by Da. It is preferable that re is slightly larger at the time of designing so that re = 0.54 Da at a low temperature at which the outer ring 12 is deformed as described above. For example, re is set to about 0.54 Da to 0.56 Da at the time of designing. Good to do.
[0017]
In the bearing 10 as described above, the circumferential groove 12b provided on the outer diameter surface of the outer ring 12 prompts the outer ring 12 to be appropriately deformed when the interference increases with a decrease in temperature. Therefore, fluctuations in the outer ring raceway diameter can be prevented. Thus, it is possible to prevent problems such as a decrease in bearing life and occurrence of abnormal noise.
[0018]
Next, based on FIG. 4, the deep groove ball bearing 20 of 1st Embodiment of this invention is demonstrated . In the embodiments described below, members having the same configuration and function as those already described are denoted by the same or corresponding reference numerals in the drawings, and description thereof is simplified or omitted.
In FIG. 4, illustration of balls is omitted.
[0019]
As shown in FIG. 4, in the present embodiment, the outer ring raceway 22a has a central curved surface having a radius of curvature re and a side curved surface that is arranged on both sides of the central curved surface and has a different center of curvature from the central curved surface. And have. In the present embodiment, the curvature radius re ′ of the side curved surface is set larger than the curvature radius re of the central curved surface.
According to this embodiment, the deformation of the outer ring as described with reference to FIG. 3 occurs smoothly, thereby preventing fluctuations in the outer ring raceway diameter.
[0020]
FIG. 5 shows a deep groove ball bearing 30 of the second embodiment . In the present embodiment, the buffer material 31 is provided in the circumferential groove 12 b of the outer ring 12. Other configurations are the same as those of the reference example and the first embodiment .
As the buffer material 31, a material that exhibits a damper action for reducing the impact load from the housing 3 side can be adopted. For example, a polymer material such as a resin can be used. It is preferable that the cushioning material 31 protrudes from the outer diameter surface of the outer ring 12 in a free state before the bearing 30 is incorporated into the housing 3.
[0021]
FIG. 6 shows a deep groove ball bearing 40 of the third embodiment. In the present embodiment, the outer ring 42 extends in the axial direction so that the axial length of the fitting surface between the outer ring 42 and the housing 3 is longer than the axial length of the fitting surface between the inner ring and the shaft. An existing extending portion 42e is provided. In the present embodiment, extending portions 42e and 42e are provided on both sides of the outer ring 42 in the axial direction. The end surface of the inner ring 11 is located on the ball 13 side from the end surface of each extending portion 42e.
According to this embodiment, an appropriate interference can be maintained by widening the outer ring width.
[0022]
In addition, this invention is not limited to embodiment mentioned above, A suitable deformation | transformation, improvement, etc. are possible.
For example, the extension may be provided only on one side in the axial direction of the outer ring.
The deep groove ball bearing can also be applied to bearing devices other than the fan coupling device.
[0023]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a deep groove ball bearing and a fan coupling device that can operate satisfactorily over a long period of time even in a wide range of operating temperatures. Further, when the outer ring is mounted on the housing, the outer ring is smoothly deformed, thereby preventing fluctuations in the outer ring raceway diameter.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a fan coupling device according to a reference example of the present invention.
2 is a cross-sectional view showing the deep groove ball bearing of FIG.
3 is a cross-sectional view illustrating the operation of the deep groove ball bearing of FIG.
FIG. 4 is a cross-sectional view illustrating a deep groove ball bearing according to a first embodiment of the present invention.
FIG. 5 is a cross-sectional view illustrating a deep groove ball bearing according to a second embodiment of the present invention.
FIG. 6 is a cross-sectional view illustrating a deep groove ball bearing according to a third embodiment of the present invention.
[Explanation of symbols]
1 Fan coupling device 2 Drive shaft (shaft)
3 Housing (outer member)
10, 20, 30, 40 Deep groove ball bearing 11 Inner ring 12, 22, 42 Outer ring 12b, 22b, 42b Circumferential groove 13 Ball 31 Buffer material 42e extension part

Claims (4)

A deep groove ball bearing including an inner ring having an inner ring raceway on an outer diameter surface, an outer ring having an outer ring raceway on an inner diameter surface, and a plurality of balls arranged between the inner and outer ring raceways, and is incorporated between a shaft and an outer member In
A circumferential groove is provided on the outer diameter surface of the outer ring to allow a variation in interference with the outer member, and the outer ring raceway has a central curved surface in a cross-sectional view before assembly to the outer member, and deep groove ball bearing, characterized in that the said central curved surfaces disposed on either side of the central curved surface and a side curved surface radius of curvature greater than the inner curved surface Ri of curvature center Do different.   The deep groove ball bearing according to claim 1, wherein a buffer material is provided in the circumferential groove. An extension that extends in the axial direction of the outer ring so that the axial length of the fitting surface between the outer ring and the outer member is longer than the axial length of the fitting surface between the inner ring and the shaft. The deep groove ball bearing according to claim 1, wherein a portion is provided.   A fan coupling device in which the deep groove ball bearing according to claim 1 is incorporated.

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