JP2004011801A - Deep groove ball bearing and fan coupling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a deep groove ball bearing and a fan coupling device well working over long time of period and even for a wide range of service temperature. <P>SOLUTION: The deep groove ball bearing 10 is provided with an inner ring 11 having an inner ring track 11a on an outside diameter surface, an outer ring 12 having an outer ring track 12a on an inside diameter surface, and a plurality of balls 13 arranged between the inner and outer ring tracks 11a and 12a. The bearing is incorporated between a spindle and an outer member. A peripheral channel 12b for permitting the variation in interference with the outer member is provided. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
The present invention relates to a deep groove ball bearing 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.
TECHNICAL FIELD OF THE INVENTION
[0002]
[Prior art]
For cooling the engine, a cooling fan is arranged so as to face the engine. In particular, a fan coupling device is used in FR vehicles. The fan coupling device has a housing in which a viscous fluid is stored and a fan for blowing air is provided on an outer peripheral portion. The housing is connected via a deep groove ball bearing to a rotor provided on a drive shaft connected to the engine. A labyrinth is provided on a relative surface between the housing and the rotor, and a viscous fluid enters the labyrinth. The driving torque from the engine is first transmitted to the rotor, and then transmitted from the rotor to the housing and the fan for blowing using the viscous resistance of the viscous fluid. The amount of torque transmitted by the viscous fluid is controlled by a valve member that opens and closes in accordance with the ambient temperature. When the engine temperature is low, the fan rotates at low speed, and when the engine temperature is high, the fan rotates at high speed. Then, perform the most suitable air blowing for the engine temperature at that time.
[0003]
Generally, in a bearing device such as the fan coupling device described above, a housing made of an aluminum alloy tends to be used in order to reduce the weight of the housing and improve heat dissipation with an increase in the speed of the drive shaft.
On the other hand, a drive shaft made of cast iron or the like is used.
[0004]
[Problems to be solved by the invention]
In the above-described 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 is reduced. Further, the temperature may further rise due to the shear resistance of the viscous fluid, and may reach 200 ° C. or more. At such a high temperature, the interference between the aluminum housing and the outer ring is lost, and creep of the outer ring may occur. In the worst case, the viscous fluid leaks out and the fan rotation cannot be properly controlled.
As described above, when the operating temperature is extremely high, the interference of the fitting portion at normal temperature is increased in order to secure the interference in a high temperature range.
[0005]
On the other hand, automobile parts such as a fan coupling device may be used at a low temperature, for example, in an atmosphere of about −40 ° C. In this case, contrary to the above, the aluminum housing tends to shrink more than the bearing outer ring, so that the bearing outer ring is forcibly compressed.
In order to prevent the interference of the labyrinth, the bearing clearance at high temperature may be set small in order to keep the bearing clearance at high temperature (the area where the interference between the housing and the outer ring is small) small. In this case, for example, at a low temperature of −40 ° C., the effective bearing clearance is −30 μm to −50 μm. In addition, at low temperatures, the fluidity of the bearing lubricant deteriorates, making it difficult for the lubricant to enter between the balls and the raceway surface, causing early surface roughening and wear, and causing abnormal noise and backlash. Sometimes. In the worst case, seizure may occur, leading 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 wide range of operating temperatures over a long period of time.
[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 raceway on an outer diameter surface, an outer race having an outer raceway on an inner diameter surface, and a plurality of balls arranged between the inner and outer raceways are incorporated between a shaft and an outer member. In a deep groove ball bearing, a peripheral groove is provided on an outer diameter surface of the outer ring so as to allow a variation in interference with the outer member.
(2) The deep groove ball bearing according to (1), wherein the peripheral groove is provided with a cushioning material.
(3) The outer ring raceway according to (1) or (2), which has a central curved surface and a side curved surface arranged on both sides of the central curved surface and having a different center of curvature from the central curved surface in a cross-sectional view. Deep groove ball bearings.
(4) The deep groove ball bearing according to any one of (1) to (3), wherein an extension is provided on the outer ring so as to extend a fitting surface between the outer ring and the outer member.
(5) A fan coupling device incorporating the deep groove ball bearing according to any one of (1) to (4).
[0008]
In the above configuration, the peripheral groove provided on the outer diameter surface of the outer ring, which is a fitting surface with the outer member such as the housing, causes the bearing when the interference in the fitting surface fluctuates with temperature change. Fluctuations in the clearance can be absorbed, and fluctuations in the outer raceway diameter can be prevented. Even when the difference in the coefficient of linear expansion between the outer member and the outer ring is large, fluctuations in the bearing gap 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 reduction in bearing life and generation of abnormal noise.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In a fan coupling device 1 shown in FIG. 1, a deep groove ball bearing (hereinafter, also simply referred to as a “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 an outer peripheral portion of the housing 3. The 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 storage space 8 for viscous fluid 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 tip side (the 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 due to the temperature change, the valve member fixed to the bimetal 7 moves, and controls the amount of torque transmitted 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 raceway 11a on an outer diameter surface, an outer race 12 having an outer raceway 12a on an inner diameter surface, and a plurality of balls 13 arranged between the inner and outer raceways 11a. The plurality of balls 13 are held by a retainer (here, a corrugated press retainer) 14 so as to be rollable at intervals in the circumferential direction.
[0012]
A peripheral groove 12b is provided on the outer diameter surface of the outer race 12 to allow a variation in interference with the housing 3. The axial dimension (groove width) X ′ of the circumferential groove 12b can be set to be equal to or smaller than the axial dimension X of the outer raceway 12a. X ′ is preferably set to 0.5X to 1.0X.
It is preferable that the radial dimension (depth) A of the circumferential groove 12b be equal to or larger than the maximum value of the radial interference between the bearing 10 and the housing 3 in the operating temperature range. For example, at a low temperature, 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, the depth A of the circumferential groove 12b is preferably (0.150 / 2) mm or more. .
[0013]
In the present embodiment, the outer raceway 12a has a single curved surface in a sectional view, and the curved surface has a single radius of curvature re.
[0014]
A pair of seal members 15, 15 are provided with the ball 13 interposed therebetween. In the present embodiment, the outer peripheral portions of the seal members 15, 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, 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.
In addition, 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 a lubricant.
[0015]
The operation when the above-described bearing 10 is installed 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 peripheral groove 12 b serve as fitting surfaces with the housing 3. At low temperatures, the interference increases, and the fitting surfaces receive the compressive force P from the housing 3. At this time, both ends in the axial direction of the outer race 12 contract with the housing 3, and the outer race 12 bends in a direction to reduce the groove radius of curvature re of the outer raceway 12a as indicated by an arrow R in the figure. That is, the outer race 12 bends so that the outer diameter surface becomes convex toward the outer periphery.
[0016]
In the figure, the ball diameter is indicated by Da. At the time of design, re should be slightly increased in advance so that re = 0.54 Da at the time of low temperature at which the deformation of the outer ring 12 occurs. For example, at the time of design, re is set to about 0.54 Da to 0.56 Da. 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 urges the outer ring 12 to be appropriately deformed when the interference increases due to the temperature drop, and the deformation of the outer ring 12 As a result, variation in the outer ring raceway diameter can be prevented. In this way, it is possible to prevent problems such as a reduction in bearing life and generation of abnormal noise.
[0018]
Next, a deep groove ball bearing 20 according to a second embodiment of the present invention will be described with reference to FIG. In the embodiments described below, the members and the like having the same configuration and operation as the members and the like already described are denoted by the same reference numerals or corresponding reference numerals in the drawings to simplify or omit the description.
In FIG. 4, illustration of the ball is omitted.
[0019]
As shown in FIG. 4, in the present embodiment, the outer raceway 22 a has, in a cross-sectional view, a central curved surface having a radius of curvature re, and side curved surfaces arranged on both sides of the central curved surface and having different centers of curvature from the central curved surface. And In the present embodiment, the curvature radius re 'of the side curved surface is set to be larger than the curvature radius re of the central curved surface.
According to the present embodiment, the deformation of the outer ring as described with reference to FIG. 3 occurs smoothly, thereby preventing a change in the outer ring raceway diameter.
[0020]
FIG. 5 shows a deep groove ball bearing 30 according to the third embodiment. In the present embodiment, a cushioning material 31 is provided in the peripheral groove 12b of the outer race 12. Other configurations are the same as those of the first embodiment.
As the cushioning material 31, a material having a damper function to reduce an impact load from the housing 3 side can be adopted, and for example, a polymer material such as a resin can be used. It is preferable that the cushioning material 31 protrude from the outer diameter surface of the outer race 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 fourth embodiment. In the present embodiment, the outer ring 42 is provided with an extension 42e so as to expand the fitting surface between the outer ring 42 and the housing 3. In the present embodiment, extension portions 42e, 42e are provided on both axial sides of the outer ring 42. The end face of the inner race 11 is located closer to the ball 13 than the end face of each extension 42e.
According to the present embodiment, an appropriate interference can be maintained by increasing the outer ring width.
[0022]
Note that the present invention is not limited to the above-described embodiment, and appropriate modifications and improvements can be made.
For example, the extension may be provided only on one axial side of the outer race.
Further, the deep groove ball bearing can be applied to a bearing device 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 favorably over a wide range of operating temperatures over a long period of time.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a fan coupling device according to a first embodiment of the present invention.
FIG. 2 is a sectional view showing the deep groove ball bearing of FIG. 1;
FIG. 3 is a cross-sectional view illustrating an operation of the deep groove ball bearing of FIG. 2;
FIG. 4 is a sectional view illustrating a deep groove ball bearing according to a second embodiment of the present invention.
FIG. 5 is a sectional view illustrating a deep groove ball bearing according to a third embodiment of the present invention.
FIG. 6 is a sectional view illustrating a deep groove ball bearing according to a fourth embodiment of the present invention.
[Explanation of symbols]
1 Fan coupling device 2 Drive shaft (axis)
3 Housing (outer member)
10, 20, 30, 40 Deep groove ball bearing 11 Inner ring 12, 22, 42 Outer ring 12b, 22b, 42b Peripheral groove 13 Ball 31 Buffer material 42e Extension

Claims (5)

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 being incorporated between a shaft and an outer member. At
A deep groove ball bearing, wherein a peripheral groove is provided on an outer diameter surface of the outer race to allow a variation in interference with the outer member. The deep groove ball bearing according to claim 1, wherein a cushioning material is provided in the peripheral groove. 3. The deep groove ball bearing according to claim 1, wherein the outer raceway has a central curved surface in cross-sectional view and side curved surfaces disposed on both sides of the central curved surface and having different centers of curvature from the central curved surface. 4. The deep groove ball bearing according to any one of claims 1 to 3, wherein an extension is provided on the outer ring so as to extend a fitting surface between the outer ring and the outer member. A fan coupling device incorporating the deep groove ball bearing according to claim 1.

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