JPH0979266A - Grease-sealed bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grease-sealed bearing which can realize low torque while durability is satisfied by sealing a necessary amount grease. SOLUTION: A grease-sealed bearing is constituted by a cylindrical outer ring 2, similarly an inner ring 3, plurality of rolling units 4 interposition inserted between the outer/inner rings 2, 3 and a crown-shaped cage 5 for rollably holding the rolling units adjacent to each other of these rolling units 4, grease G is sealed in an upper surface of each pillar 5b of this cage 5 further is a back surface of a pocket 5a in an end face in an opposite side to the axial direction, and an amount of these sealed grease G is set to about 30% the total unit of internal space.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grease-filled bearing suitable for a fan motor bearing and the like which are particularly required to have durability and low torque.

[0002]

2. Description of the Related Art Conventional grease-filled bearings are generally
From the aspect of production efficiency, etc., semi-solid grease mainly consisting of a thickener and a liquid lubricant (base oil) is filled from only one side of the cage. For example, in a miniature type grease filled bearing, Place grease on each pillar between adjacent rolling elements on one axial side of the internal cage, and seal it.
Lubrication is performed by softening the grease as the temperature of the rolling elements of the bearing rises and softening the grease, and allowing the grease to flow out little by little to the raceways of the rolling elements.

[0003]

However, in the conventional grease-filled bearing described above, when the grease filling amount is small, the grease is not effectively leaked to the raceway surface and effective lubrication is performed to achieve raceway. Although low torque of the wheels can be realized, particularly for fan motor bearings that require durability, the amount of grease to be filled is generally required to be about 30% of the bearing internal space volume. If the grease is sealed from only one side in the axial direction, the grease excessively flows out to a part of the raceway surface to increase the flow resistance of the grease, which causes a problem that low torque cannot be realized.

Further, the grease arranged in a large amount on one side in the axial direction of the cage flows out due to the centrifugal force generated by the rotational movement of the cage, which is biased toward the outer ring side as the cage rotates. There was also a problem that it became easier to do. Therefore, the present invention has been made by paying attention to the unsolved problem of the above-mentioned conventional example, and encapsulating a required amount of grease to satisfy the durability, and further, encapsulating the grease capable of realizing a low torque. The purpose is to provide a bearing.

[0005]

In order to solve the above problems, a grease-sealed bearing according to the present invention comprises an inner ring, an outer ring, and a plurality of rolling elements rolling between the inner ring and the outer ring.
In a grease-sealed bearing equipped with a retainer for holding the rolling element and grease arranged on one end face of the retainer in the axial direction, grease is also applied to the end face of the retainer in the opposite axial direction. The feature is that the required amount of grease is divided on both sides in the axial direction by placing it on top of each other.

[0006] As a result, the grease becomes
Alternatively, the grease is evenly supplied from both side surfaces of the cage without excessively flowing out to a part of the race surface between the cage and the rolling elements, and low torque of the bearing ring is secured. Furthermore, by arranging a small amount of grease on both sides of the cage in the axial direction, it is possible to reduce the centrifugal force applied to the grease due to the rotation of the cage, and prevent a large amount of grease from flowing out to the outer ring side. You can

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, reference numeral 1 denotes a grease-filled bearing, and the present invention is applied to a miniature type deep groove ball bearing having a bearing outer shape of less than about 10 mm. This grease-filled bearing 1 has a cylindrical outer ring 2
, The inner ring 3, a plurality of rolling elements 4 interposed between the outer ring 2 and the inner ring 3, and rolling elements 4 adjacent to the rolling elements 4.
And a retainer 5 having a crown shape for rotatably holding.

On the inner peripheral portion of the outer ring 2 and the outer peripheral portion of the inner ring 3, raceway grooves 2a of the rolling element 4 are provided so as to face each other.
3a is provided, and a part of the rolling element 4 is guided in the raceway grooves 2a, 3a. In addition, as shown in FIG. 2, the cage 5 is a resin molded cage integrally molded by an injection molding machine using a material having low friction and flexibility such as nylon, and its shape as a whole. A pocket 5a which forms an annular body and has an opening formed of an inner circumferential arc having substantially the same curvature as that of the rolling element 4 so as to include and hold a plurality of rolling elements 4 at one end in the axial direction of the annular body at equal intervals; Each adjacent pocket 5a,
It is composed of a pillar portion 5b provided between the 5a.

Grease G is alternately filled in the pillar portion 5b on one axial end surface of the cage 5 and on the back surface of the pocket 5a on the other axial end surface. The total amount of the grease G filled in this way is about 30% of the entire internal space in this embodiment. Further, in order to seal the enclosed grease G, the shield 6 made of a steel plate is caulked on the outer peripheral portion of the shield 6 in the seal engaging grooves provided on the inner peripheral portions of both axial ends of the outer ring 2. It is attached, and is provided so as to extend from there to the inner ring 3.

A grease-filled bearing 1 having such a structure
For example, when the drive shaft attached to the inner ring 3 rotates, the inner ring 3 that serves as a bearing ring rotates along with the rotation of the drive shaft, and as a result, the rolling element 4 and the inner and outer rings 2, 2 of the grease-filled bearing 1 rotate. 3 and the cage 5, the grease is repeatedly subjected to shearing force, and the thickener fiber is gradually shredded and softened, and when the apparent viscosity of the grease G approaches the viscosity of the base oil, this increases. Lubrication is performed by uniformly flowing out from both end faces in the direction to the raceway surface to form an oil film. After that, when the rotation of the grease-filled bearing 1 stops, the grease returns to the original semi-solid state.

A small amount of grease G is provided on both axial end surfaces of the cage 5, without being biased toward the outer ring 2 side by the influence of centrifugal force, or between the rolling element 4 and the inner and outer rings 2 and 3, or It evenly flows out between the rolling elements 4 and the cage 5. Next, the following tests were performed using this grease-filled bearing 1. This test is performed on the pillar portion 5b of the cage 5 on the one end surface in the axial direction.
Further, the distribution of the grease G filled in the back surface of the pocket 5a at the other end surface in the axial direction is changed to change the grease filled bearing 1
The torque is measured by attaching a torque meter (not shown) to the drive shaft attached to the inner ring 2.

As a result, as shown in FIG. 3, the amount of grease G filled in the back surface of the pocket 5a on the axially opposite side is 20 to 50% of the total amount of grease filled, preferably 30 to 50%.
The result was that stable low torque could be secured when 40% was filled. Further, the grease-filled bearing 1 constituted by filling the grease G to be filled in the back surface of the pocket 5a, which has obtained good results in the above test, in an amount of about 30 to 40% of the total amount of grease filled, is used as the test object a, The grease-filled bearing 1 in which the same amount of grease G as that in the grease-filled bearing 1 is filled only in the column portion 5b on one axial end surface of the cage 5 is used as the test object b. 10 after powering on the drive shaft attached to the inner ring 3
The number of revolutions after 2 seconds was comparatively measured.

As is clear from the test results, as shown in FIG.
Despite being 500 rpm, the test object b, which is a product of the present invention, had a speed of 4700 to 5500 rpm. From the above test results, the grease-filled bearing 1 has the pillar portion 5b of the cage 5 on one side in the axial direction and the pocket 5 on the opposite side in the axial direction.
By appropriately changing the distribution of the grease G to be sealed on the back surface of b, the durability is secured without reducing the required grease amount, and the grease G is excessive on a part of the raceway surface. Low torque can be realized without flowing out.

In the above embodiment, the brand of the grease G used is Multemp SRL: No3 (trade name), but it is not always necessary to use this grease G and another grease G is selected and used. You can also
Further, in the above-described embodiment, the configuration in which the grease G is enclosed in each column portion 5b of the cage 5 on the one side in the axial direction and the back surface of the pocket 5a has been described, but the grease G is not necessarily enclosed in the end surface on the opposite side in the axial direction. The grease G is not limited to the back surface of the pocket 5a, but the grease G may be uniformly filled in the entire end surface on the opposite side in the axial direction.

In the above embodiment, the case where the resin-molded crown-shaped cage 5 is used has been described.
In addition to this, as shown in FIG. 5, a corrugated cage 7 is used instead of the crown-shaped cage 5, which is formed by press working two steel plates and then joined integrally by rivets or the like. The grease G is evenly filled in both axial end faces of the connecting portion 7 between the pockets 5a containing the rolling elements 4 from both sides in the axial direction of the cage 7 of FIG. The same effect can be obtained.

Further, in the above embodiment, the single row deep groove ball bearing has been described, but it is needless to say that the present invention can be applied to an angular ball bearing, a double row angular ball bearing, a roller bearing and the like.

[0017]

As described above, according to the grease sealed bearing of the present invention, the grease does not excessively flow out to a part of the race surface between the rolling element and the race ring or the cage and the rolling element. By being evenly supplied to the raceway surface, the required amount of grease specified by the customer etc. is secured and durability is maintained without significantly increasing the production cost, and
The load on the drive shaft can be reduced.

[Brief description of drawings]

1 shows a grease-sealed bearing according to an embodiment of the present invention, FIG. 1 (a) is a plan view, and FIG. 1 (b) is a sectional view taken along line AA of FIG. 1 (a).

2 is a perspective view showing the crown-shaped cage of FIG. 1. FIG.

FIG. 3 is a graph showing the relationship between the distribution of the amount of grease filled in the grease-filled bearing according to the embodiment of the present invention and the rotational torque of the drive shaft.

FIG. 4 is a graph showing rotational torques of the grease-sealed bearing according to the embodiment of the invention and a conventional product.

FIG. 5 is a perspective view showing a grease-filled bearing using a corrugated cage.

[Explanation of symbols]

 1 is a grease filled bearing 2 is an outer ring 3 is an inner ring 4 is a rolling element 5 is a retainer 5a is a pocket 5b is a pillar 6 is a shield 7 is a connecting part

Claims (1)

[Claims] 1. An inner ring, an outer ring, a plurality of rolling elements that roll between the inner ring and the outer ring, a cage that holds the rolling elements, and an end surface of the cage on one axial side. In a grease-filled bearing provided with a grease that is arranged in a line, the required amount of grease is divided into both sides in the axial direction by placing the grease on the end surface of the cage on the opposite side in the axial direction. Bearing with grease.