JPS5838167Y2 - rolling bearing - Google Patents

Description

[Detailed description of the invention] The present invention relates to the improvement of rolling bearings, and more specifically, it proposes a rolling bearing suitable for use when assembled into an axle box that has a larger coefficient of thermal expansion than the inner and outer rings of the bearing. It is.

For example, an aluminum axle box is used in an automobile alternator to reduce weight, and the ball bearing incorporated in the axle box is shown in FIG.

That is, an outer ring 3 of a ball bearing 2 is fitted into an axle box 1 made of aluminum, and a shaft 5 is fitted into an inner ring 4 to rotatably support the shaft 5.

Incidentally, the aluminum axle box 1 has a coefficient of thermal expansion approximately twice as large as that of the bearing steel of the ball bearing 2, and the alternator is required to have an extremely wide operating temperature range.

Therefore, the interference at the fitting portion between the axle box 1 and the bearing outer ring 3 decreases in a high temperature range, and increases in a low temperature range.

Therefore, in order to prevent the outer ring 3 from slipping and creep due to the reduction in the shear in the high temperature range, if the shear is increased during assembly at room temperature, the contact between the inner and outer rings and the rolling elements inside the ball bearing is increased. The residual clearance between the bearings becomes a large negative value, and as a result, in a low temperature range, the interference becomes excessively thick, causing an abnormal load to be applied between the inner and outer rings and the rolling elements, resulting in damage to the bearing.

On the other hand, if the interference at the time of assembly is made small in order to avoid this bearing damage, the interference will disappear in a high temperature range, resulting in the problem of creep.

In order to solve these problems, a ball bearing has been proposed in which an annular groove is formed in the outer ring of the ball bearing and a plasticizer with a large coefficient of thermal expansion is filled between the annular groove and the axle box ( Special Public Sho 3
However, in this type of bearing, there is almost no interference between the outer circumferential surface of the outer ring and the axle box in a high temperature range, and the bearing is held only by the interference between the plasticizer and the axle box.

Moreover, since the bearing is held in a state where the contact area of the contact portion is also reduced, there is a drawback that the holding of the bearing lacks stability.

The present invention was developed in view of the above circumstances, and as mentioned above, the bearing is made of an axle box made of a material such as aluminum, which has a coefficient of thermal expansion larger than that of the bearing ring of the bearing. Even when assembled, the bearing is held securely, has high reliability over a wide temperature range, and has a long service life.
This proposed rolling bearings such as ball bearings.

The features of the rolling bearing according to the present invention are as follows.

(1) An annular groove is formed on the outer circumferential surface of the outer ring or the inner circumferential surface of the inner ring of the bearing, which expands and deforms outwards as the mounting interference increases due to a drop in temperature.

(2) The bearing ring and the bearing are installed so that the interference between them is minimized in the highest operating temperature range of the bearing.

Now, the ball bearing itself, which has an annular groove around the outer ring, is known for the purpose of directly hanging a belt on the ball bearing using this annular groove, and also has an annular groove around the inner and outer rings. The ball bearing itself is subject to Hertzian stress (Hertzian 5t), which is the main cause of fatigue failure in ball bearing assemblies.
It is known for the purpose of reducing (
U.S. Pat.
It is clearly different from the conventional technology in that it is used as it is without being filled with plasticizer, unlike the No. 55, and in addition, the outer ring outer diameter is It is characterized by the fact that the dimensions are determined.

The present invention will be explained in detail below with reference to drawings showing embodiments of a ball bearing.

FIG. 1 is a half-cut vertical cross-sectional view of a ball bearing according to the present invention, and FIG. 2 is a half-cut vertical cross-sectional view showing another embodiment of the ball bearing according to the present invention.

In FIG. 1, 10 is an inner ring, 20 is an annular outer ring disposed concentrically with the inner ring 10, 30 is a ball disposed on the circumference between the inner ring 10 and the outer ring 20, and 40 is a ball disposed so as to be freely movable. This is a retainer arranged on both sides of the ball 30.

50 is an inner ring 10 and an outer ring 2 on both sides of the ball 30.
These members constitute a ball bearing.

An annular groove 20a having a width C1 and a depth is formed on the outer circumferential surface of the outer ring 20, and the center position of the annular groove 20a in the width direction and the center of the ball 30 are aligned approximately on the same line. The strength of the outer ring 20 near the line is weakened.

Further, the width C of the annular groove 20a is selected to be approximately the same as the diameter of the ball 30.

The outer diameter of the outer ring 20 is slightly larger than the inner diameter of an aluminum axle box (not shown) into which the outer ring 20 is inserted, and is the minimum diameter that can prevent creep, especially at the maximum operating temperature. The outer diameter of the outer ring 20 is selected so that a shimmy remains.

In this way, when a ball bearing in which the annular groove 20a is formed on the outer circumferential surface of the outer ring 20 is assembled into an axle box having a coefficient of thermal expansion larger than that of the ball bearing, the outer ring 20 of the ball bearing is Ring groove 2 is tightly fitted into the box and has weak strength.
The bottom surface of 0a curves and bulges outward as shown by the broken line, and the tightening load between the inner and outer rings and the balls generated inside the ball bearing is alleviated.

Therefore, when the ball bearing is at a high temperature, the inner diameter of the axle box, which has a larger coefficient of thermal expansion than the ball bearing, becomes larger than the outer ring of the ball bearing.
Although the outer diameter of the outer ring 20 is larger than the outer diameter of 0, and the interference is reduced, the outer diameter of the outer ring 20 is selected so that the minimum interference that can prevent creep against the axle box remains. The amount of bulge of the groove 20a is only slightly reduced, and the bearing is held stably as it would be at room temperature, with an appropriate amount of interference remaining.

In FIG. 2, an annular groove 10a having a width C1 and a depth is formed on the inner circumferential surface of the inner ring 10.

In this case as well, the outer diameter of the outer ring is set to be slightly larger than the inner diameter so that the shims remain, especially at the maximum operating temperature.

The rest of the structure is the same as that shown in FIG. 1, so corresponding members are given the same numbers and explanations will be omitted.

Next, an example of the dimensions and characteristics of the outer ring having an annular groove as shown in FIG. 1 will be shown.

(A) Dimension type: +6203 % formula %) Shaft diameter: 17 (+0.013) wnn Shinro 17 μm Axle box inner diameter: 40 (-0,053) g Shimeshiro 48 μm Residual clearance: -33 m (negative clearance) Ring groove depth '
, D = 0.5mm Ring groove width, C = 5.0mm However, the values in parentheses are dimensional tolerances (B) Characteristics Starting friction torque 232gr-Cm This is a conventional product with the same interference and residual clearance. Approximately 1/ of
It is 2.

■ Temperature rise 50 degC (rotation speed 400 Or, p, m,) 5 deg C (rotation speed 6000 r, p, m,) This is approximately 85% of the conventional product with the same interference and residual clearance.

■Life test conditions Radial load: 375Kg (50 times the dynamic load rating) or 525 (same as 70 factors) Rotation speed: 2000r, p, m Test results Over 281 hours (load 375Kg) 132 hours (same <525) (9) This is a sufficiently long value compared to the conventional product, which has the same interference and residual clearance.

Comparative tests were conducted on various values of the depth C of the annular groove, but the above-mentioned value of 0.5 mm was the most effective.

Further, as mentioned above, it is appropriate that the width of the annular groove be approximately equal to the diameter of the ball.

The reason why the bearing according to the present invention exhibits the above-mentioned excellent characteristics is that by providing the annular groove, the outer ring or the inner ring can move outside the bearing at that part as shown in Fig. 1 or 2. This is presumed to be due to the bulging deformation in the opposite direction, which reduces the tightening load between the inner and outer rings and the balls that occurs inside the bearing.

As described above, in the case of the present invention, (1) the internally generated load is approximately 1/2 compared to the conventional product;
Also, rotational frictional resistance is reduced.

(2) Temperature rise during rotation is reduced, extending life.

(3) Therefore, a large negative residual clearance can be maintained, and bearing damage or creep can be avoided.

That is, according to the present invention, it is possible to provide a rolling bearing that has high reliability over a wide temperature range and has a long life.

[Brief explanation of drawings]

FIG. 1 is a half-cut vertical cross-sectional view of a ball bearing according to the present invention, and FIG. 2 is a half-cut vertical cross-sectional view showing another embodiment of the ball bearing according to the present invention. FIG. 3 is a longitudinal sectional view of the ball bearing assembled into the axle box. 1... Axle box, 3, 20... Outer ring, 4, 10... Inner ring, 10a, 20a... Peripheral groove.

Claims (3)

[Scope of utility model registration request] (1) The bearing is mounted on an axle box made of a material with a coefficient of thermal expansion larger than that of the outer ring with sufficient interference to prevent creep of the bearing ring, and is capable of operating in a high temperature range. The rolling bearing used is characterized in that an annular groove is formed on the outer circumferential surface of the outer ring or the inner circumferential surface of the inner ring of the bearing, which bulges out and deforms to the outside of the bearing as the mounting interference increases due to a drop in temperature. rolling bearings. (2) When installing the bearing outer ring and axle box,
A rolling bearing according to claim 1 of the utility model registration, characterized in that the temperature is minimized in the highest operating temperature range of the bearing. (3) Utility model registration claim 1, characterized in that the width of the circumferential groove is approximately the same as the width of the rolling elements of the bearing.
Rolling bearings as described in section.