JPH0520897Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a rolling bearing device, and particularly when it is mounted on a shaft with a linear expansion coefficient different from that of the inner ring and used at high temperatures, This effectively prevents damage to the bearing due to thermal stress caused by differences in linear expansion coefficients and linear expansion coefficients.

[Conventional technology]

As a conventional bearing mounting structure for shafts having different coefficients of linear expansion, a rolling bearing as shown in FIG. 5 is shown in an article on pages 407 to 415 of the July 1981 issue of LUBRICATION ENGINEERING. In this bearing, the inner ring 1 is made of ceramic, and the spacer 2
is made of steel. The spacer 2 is in contact with the inner ring 1 at a tapered surface, and is in "tight fit" with the shaft 3. On the other hand, the inner ring 1 is provided with a "loose fit" to the shaft 3, so that even if the shaft 3 and the spacer 2 expand thermally, an excessive load will not be applied to the bearing. 4 is an outer ring, 5 is a roller as a rolling element, and 6 is a retainer for the roller 5.

[Problem that the invention attempts to solve]

However, in such a conventional rolling bearing device, when a bearing load acts, the contact surface pressure of the tapered surface increases, which increases wear, vibration, runout during rotation, etc. of the bearing device. Furthermore, when the bearing load increases, the tapered surface becomes unable to support the load, and in the worst case, the bearing may be destroyed. Additionally, if a sudden temperature change occurs during bearing operation, the difference in linear expansion coefficient between the inner ring and the shaft will cause imbalance as the fitting clearance decreases.
There was a tendency for the inner ring to tilt with respect to the shaft.

The object of this invention is to provide a rolling bearing device that eliminates such conventional problems.

[Means for solving problems]

This idea is based on a rolling bearing device in which the coefficient of linear expansion of the inner ring of the bearing is different from that of the shaft on which the inner ring is mounted, and the inner ring has a loose fit with the shaft, and both end surfaces thereof are outward from the center of the bearing. a pair of inner spacers formed on an opening inclined surface, sandwiching the inner ring through the inclined surfaces, and firmly engaging with the shaft with the same coefficient of linear expansion; The present invention is characterized in that it includes an outer spacer which is located on the outside, tightly engages with the shaft, and has an end bent inward, and the end is engaged with the outer circumferential surface of the inner ring.

[Effect]

By making the engagement surface between the inner spacer and the inner ring sandwiched therebetween an inclined surface, the difference in the amount of elongation in the axial and radial directions that appears when the temperature rises is reduced due to the difference in linear expansion coefficient between the inner ring and the shaft. be absorbed.

Furthermore, by supporting the cylindrical outer peripheral surface of the inner ring held by the inner spacer on the outer spacer, the load applied to the inner ring is dispersed. At the same time, the inner ring and the shaft are always kept concentric by regulating the inclination of the inner ring with respect to the shaft with an outer spacer tightly fitted to the shaft.

〔Example〕

Hereinafter, embodiments of the present invention will be described based on the drawings. Note that the same reference numerals in each figure represent the same or corresponding parts.

Figure 1 shows a first embodiment in which this invention is applied to a radial cylindrical roller bearing, in which the bearing rings include an outer ring 4 and an inner ring 1.
1, and an inner ring 11, which is one bearing ring, is fitted with a clearance fit to a shaft 3, which is a mating member to which it is attached. The inner ring 11 is made of ceramic and has a smaller coefficient of linear expansion than the shaft 3 made of bearing steel. In addition, both end surfaces 11a and 11b of the inner ring 11 are formed as inclined surfaces that open outward with respect to the bearing center O, and the inclination angles are θ _a and θ _b respectively (hereinafter, the case where θ _a = θ _b = θ will be described). It is.

On the axially outer side of this inner ring 11, there is an inner spacer 12 made of a pair of metal annular bodies.

These inner spacers 12 have the same coefficient of linear expansion as the shaft 3, and are tightly fitted to the shaft 3 with an interference fit or a stop fit. Further, each inner spacer 12 has an inclined surface at an end thereof having an inclination angle θ that engages with the inner ring inclined surfaces 11a and 11b, and the inner ring 11 is held between the inclined surfaces.

These inclination angles θ are the center diameter D _p of the inner ring 11,
Inner ring width W _p at its center diameter D _p and inner ring 1
The linear expansion coefficient α _j of the inner spacer 12 and the linear expansion coefficient α _s of the inner spacer 12 are selected so that the following relationship holds true.

When α _j <α _s , θ≧tan ^-1 (W _p /D _p ) ...(1) When α _j > α _s , θ≦tan ^-1 (W _p /D _p ) ...(2) That is, If the linear expansion coefficient α _j of the inner ring 11 is smaller than the linear expansion coefficient α _s of the inner spacer 12 as in this embodiment, for example, due to temperature rise, the inclined surfaces 11 a and 11 b will be formed from each inner spacer 12 to the inner ring 11. A large compressive force acts through it. In that case, by setting the inclination angle θ as large as possible based on the strength of the inner ring according to equation (1), the surface pressure per unit area on the inclined surface can be lowered.
The purpose is to increase the load-bearing capacity of the slope as much as possible. This makes it possible to increase the resistance force when a difference in elongation in the axial and radial directions occurs between the inner ring 11 and the inner spacer 12 due to temperature changes during use of the bearing.

Further, the outer diameter of the inner spacer 12 is made somewhat smaller than the outer diameter of the inner ring 11, so that the cylindrical outer circumferential surface of the inner ring 11 protrudes from the outer circumferential surface of the inner spacer 12. It is designed to apply a pressing force of .

The outer spacer 13 is located on the axially outer side of the inner spacer 12, and is tightly fitted to the shaft 3, which is a mating member, with an interference fit or a stop fit. In addition, the outer peripheral end is connected to the inner ring 1.
A cylindrical portion 13a is formed by bending inward toward the inner ring 11, and an end inner surface 13b of the cylindrical portion 13a is brought into surface contact with the end of the cylindrical outer peripheral surface of the inner ring 11 as a guide surface.

Next, we will discuss the effect.

The rolling bearing device of this invention was attached to the shaft 3 as shown in FIG. 1, and the temperature was raised while the shaft 3 was rotating. The amount of elongation in the axial and radial directions due to thermal expansion of the bearing components is larger for the inner spacer 12 made of bearing steel than for the inner ring 11 made of ceramic.
1 is subjected to thermal stress through the inclined surfaces 11a and 11b that engage with each other. However, by selecting the inclination angle θ of the inclined surface based on equation (1), it was confirmed through experiments that the above thermal stress could be kept within the allowable range.

Furthermore, a part of the stress applied to the inner ring 11 becomes an upward component force on the inclined surfaces 11a and 11b, and as a result, it is received by the end inner surface 13b of the cylindrical portion 13a of the outer spacer 13, and the inclined surface 11
The burden on a and 11b has been reduced accordingly.

FIG. 2 shows a second embodiment of the invention.

This embodiment, like the first embodiment, is applied to a radial cylindrical roller bearing. However, the cylindrical portion 23a of the outer spacer 23 has an inner surface 2 at its end.
3b not only comes into contact with the outer peripheral surface of the inner ring 11, but also
The end outer surface 23c is formed as a guide surface for the retainer 6, and the vertical end surface 23d at the end of the cylindrical portion 23a
This embodiment differs from the first embodiment in that it also serves as a guide surface for the rolling elements 5. This has the advantage of further improving bearing assembly accuracy.

FIG. 3 shows a third embodiment of the present invention, which is applied to a radial tapered roller bearing. Since the rolling elements 5 are tapered rollers, other constituent members such as the outer ring 4, cage 6, inner ring 11, and inner spacer 1
2. Although the shape and relative size of the outer spacer 13 and the like differ from those of the first embodiment shown in FIG. 1, there is no essential difference in their functions and effects.

FIG. 4 shows a fourth embodiment of the present invention, which is applied to a radial deep groove ball bearing. In this case as well, since the rolling elements 5 are spherical, the shapes of the outer ring 4 and the inner ring 11, especially the raceway surfaces in contact with the rolling elements 5 are recessed, are those of the first embodiment shown in FIG. However, there is no essential difference in their actions and effects.

In each of the above embodiments, the inner ring is made of ceramic, but it is of course applicable to steel or other materials.

Furthermore, the magnitude of the inclination angle on the inclined surface where the inner ring and the inner spacer engage are equal on the left and right sides (θ _a =
Although the case of θ _b ) has been described, it is also possible to set it to a different size.

[Effect of idea]

As explained above, this invention makes both end surfaces of the inner ring in a bearing an inclined surface that opens outward with respect to the center of the bearing, supports this with an inner spacer that is firmly engaged with the shaft, and further peripheries the inner ring. Since the surface is supported by the outer spacer, the thermal stress applied to the inner ring due to temperature changes during operation can be shared and supported by the outer and outer spacers, and as a result, the contact pressure on the inclined surface is reduced. At the very least, bearing equipment wear, vibration,
The effect of significantly reducing vibrations during rotation, etc. can be obtained. Furthermore, even if the bearing load becomes large, the inclined surface will not be unable to support the load. In addition, alignment when attaching the inner ring to the mating shaft is dramatically easier and more accurate than before, and even after a load is applied, unbalanced changes in the attachment condition such as misalignment do not occur. This has the effect that the bearing can continue to operate while maintaining high accuracy.

[Brief explanation of the drawing]

Figures 1 to 4 are sectional views of essential parts showing embodiments of the present invention, respectively. Figure 1 shows the first embodiment applied to a radial cylindrical roller bearing, and Figure 2 shows the same applied to a radial cylindrical roller bearing. The second example applied,
FIG. 3 shows a third embodiment applied to a radial tapered roller bearing, and FIG. 4 shows a fourth embodiment applied to a radial deep groove ball bearing. FIG. 5 is a sectional view of a main part of a conventional rolling bearing device. 1, 11...Inner ring, 3...Shaft, 4...Outer ring, 5
...Rolling element, 6...Cage, 11a, 11b...
Inclined surface of inner ring, 12... Inner spacer, 13... Outer spacer, O... Bearing center.

Claims (1)

[Claims for Utility Model Registration] (1) In a rolling bearing device in which the coefficient of linear expansion of the inner ring of the bearing is different from that of the shaft on which the inner ring is mounted, the inner ring is fitted with the shaft in a loose fit, and the inner ring has a loose fit with the shaft, and a pair of inner spacers that are formed into inclined surfaces that open outward with respect to the center of the bearing, sandwich the inner ring through the inclined surfaces, and that have the same coefficient of linear expansion and are tightly engaged with the shaft. and an outer spacer which is located on the outside of the inner spacer and is firmly engaged with the shaft, and has an end bent inward and the end is engaged with the outer circumferential surface of the inner ring. A rolling bearing device featuring: (2) The inner ring has an inclination angle θ _a , θ _b of both end faces, a center diameter D _p of the inner ring, a width W _p at the center diameter, a linear expansion coefficient α _j of the inner ring, and a linear expansion of the inner spacer. The correlation between the coefficients α _s is expressed as θ _a , θ _b ≧tan ^-1 (W _p /D _p ) when α _j <α _s , and θ _a , θ _b ≦tan ^-1 (W p / D _p ) when α _j > α _s . The rolling bearing device according to claim 1, which is characterized in that it is formed so that D _p ) is satisfied.