JP2782853B2 - Inner ring mounting structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a case where an inner ring of, for example, a rolling bearing or a sliding bearing is attached to a shaft made of a material having a different coefficient of linear expansion from the inner ring and used at a high temperature or a low temperature. More particularly, the present invention relates to a mounting structure for preventing damage to an inner ring due to an increase in a transmission load and a thermal stress.

[Conventional technology]

Conventionally, for example, a report on a mounting structure in a case where the linear expansion coefficient of a rolling bearing is different from that of a mating member to which the rolling bearing is attached has been published in LUBRICATION ENGINEERIG July 1981, 407-41.
It is listed on page 5.

In this rolling bearing, as shown in FIG. 2, a cylindrical roller 5 with a retainer 6 is arranged between an inner ring 2 attached to a shaft 1 and an outer ring 3 attached to a shaft box (not shown). The shaft 1 is made of a steel material, and the inner ring 2 is made of a ceramic material. Both end surfaces in the axial direction of the inner ring 2 are tapered surfaces that expand outwardly with respect to the center axis and are fitted to the shaft 1 by loose fit. Both end surfaces of the inner ring 2 are sandwiched by a pair of spacers 4 made of a steel material fitted to the shaft 1 by an interference fit, and when the shaft 1 and the spacer 4 are thermally expanded, the inner ring 2 and the inner ring 2 are in contact with each other. An excessive load does not act due to the relative sliding of the spacer 4 on the clamping surface.

[Problems to be solved by the invention]

In the above-mentioned rolling bearing, the load applied to the bearing is enlarged by the wedge action of the both end faces of the inner ring 2 and transmitted to the spacer 4, so that the contact surface pressure on the both end faces of the inner ring 2 is remarkably increased, resulting in wear. In some cases, inconveniences such as breakage or breakage due to the limit of the applied load may occur, and the upper limit of the applied load is limited to a small value.

Further, when the inner ring 2 and the spacer 4 are assembled to the shaft 1, a relative slip occurs between the inner ring 2 fitted with the clearance fit and the spacer 4 fitted with the interference fit. However, accurate centering is difficult, and the assembling work requires skill, and there is a problem in workability.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and is less likely to cause wear and breakage of the inner ring when the inner ring having a linear expansion coefficient different from that of the shaft is in operation, and it is easy to accurately assemble the inner ring to the shaft. It is an object of the present invention to provide a mounting structure that can be used.

[Means for solving the problem]

In order to achieve the above object, in the first invention, an intermediate value of each coefficient of linear expansion between the shaft and the inner ring is provided between the shaft and an inner ring attached to the outer periphery of the shaft. A fitting member having a linear expansion coefficient of? Is interposed and fitted, and one of the fitting surface between the fitting member and the inner ring and the fitting surface between the fitting member and the shaft is firmly fixed by the engagement means. Engaging, at least one of the other mating surfaces,
Grooves formed in the circumferential direction at intervals in the axial direction, or single or multiple spiral grooves are provided.

In the second invention, a linear expansion coefficient substantially equal to one of the shaft and the inner ring is provided between the shaft and an inner ring having a different linear expansion coefficient from the shaft and attached to an outer periphery of the shaft. And a fitting surface between the mounting member and the shaft or the inner ring having substantially equal linear expansion coefficients is firmly engaged by the engagement means, and the linear expansion coefficients are not equal. At least one of the fitting surfaces of the attachment member and the inner ring or the shaft is provided with a groove formed in the circumferential direction at an interval in the axial direction, or a single or multiple spiral groove.

[Action]

In the first invention, the inner ring mounted on the shaft via the mounting member transmits the load applied to the inner ring to the shaft via the mounting member, and at least one fitting surface between the shaft and the mounting member is provided. When a circumferential or helical groove is formed, the load transmission from the mounting member to the shaft is performed by a convex portion between the groove of the fitting surface and the groove, and the transmission of the load between the mounting member and the inner ring is performed. When a circumferential or spiral groove is formed on at least one of the fitting surfaces, the load is transmitted from the inner race to the mounting member by a convex portion between the grooves on the fitting surface.

When a temperature change occurs between the time when the inner ring is mounted and the time when the inner ring is used, the interference between the fitting member shaft and each fitting surface with the inner ring changes due to a difference in linear expansion coefficient. The change is absorbed by a change in the amount of elastic deformation of the convex portion provided on at least one surface of the fitting surface between the mounting member and one of the shaft and the inner ring, and On the fitting surface between the member and the other member of the shaft or the inner ring, since the mounting member has a linear expansion coefficient of an intermediate value between the shaft and the inner ring, the inner ring is directly fitted to the shaft. The change in interference is reduced as compared with the case. Due to these synergistic effects, increase and decrease of the fitting surface stress are suppressed to a minimum.

In the second invention, the inner race mounted on the shaft via the mounting member transmits the load applied to the inner race to the shaft via the mounting member.

In this case, when the linear expansion coefficient of the mounting member is substantially equal to that of the shaft, the load transmission from the inner ring to the mounting member is formed in a circumferential direction or a spiral on at least one of the fitting surfaces of the inner ring and the mounting member. When the linear expansion coefficient of the mounting member is substantially equal to that of the inner ring, the load transmission from the mounting member to the shaft is performed by at least one of the mounting member and the shaft. This is performed by a convex portion between the grooves formed in the fitting surface in a circumferential direction or a spiral shape.

When a temperature change occurs between the time when the inner ring is mounted and the time when the inner ring is used for operation, one of the fitting surfaces of the mounting member and the inner ring that is different from the linear expansion coefficient of the mounting member is different from that of the other member. In the fitting surface, the interference changes, but the change in the interference is absorbed by the change in the amount of elastic deformation of the convex portion provided on at least one surface of the fitting surface. Also, there is almost no change in interference on the fitting surface with one of the other members that is substantially equal to the linear expansion coefficient of the mounting member. For this reason, the increase and decrease of the fitting surface stress are suppressed to a minimum.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention for a ball bearing. The ball bearing shown in FIG. 1 includes an inner ring 20, an outer ring 30, and a ball 53 that is held and guided by a retainer 54 between the inner ring 20 and the outer ring 30 and rolls. It is fitted via a member 40. The mounting member 40 is the shaft 10
The inner ring 20 is held between the flange portion 15 of the mounting member 40 by the holding nut 19 screwed to the mounting member 40, and the inner ring 20 is held between the flange portion 15 of the mounting member 40 by the holding nut 18 screwed to the mounting member 40. It is installed in a state where

For the material of the inner ring 20 and the shaft 10 of the ball bearing,
Are made of a ceramic material, and the shaft 10 is made of a steel material.

The mounting member 40 is made of a material having a coefficient of linear expansion intermediate between the respective coefficients of linear expansion of the shaft 10 and the inner ring 20, for example, cast iron, nickel steel, invar (first invention), or the shaft 10 and the inner ring 20 20 (second invention).

In the first invention, for example, a spiral groove 13 is formed on the outer peripheral surface 12 of the shaft 10, and a convex portion between the groove 13 and the groove 13 is formed.
14 is fitted to the inner peripheral side fitting surface 41 of the mounting member 40 with interference, and the inner peripheral side fitting surface 21 of the inner race 20 is firmly engaged with the outer peripheral surface 42 of the mounting member 40 for mounting.

Alternatively, contrary to the above mounting, a groove is formed in the outer peripheral surface 42 of the mounting member 40, and an inner ring is formed in a convex portion between the grooves.
The inner peripheral side fitting surface 41 of the mounting member 40 may be firmly engaged with the outer peripheral surface 12 of the shaft 10 for mounting.

In the above-described mounting structure, instead of forming a groove on the outer peripheral surface 12 of the shaft 10, a groove may be formed on the inner peripheral side fitting surface 41 of the mounting member 40, or a groove may be formed on both surfaces. Often,
Instead of forming a groove on the outer peripheral surface 42 of the mounting member 40, a groove may be formed on the inner peripheral side fitting surface 21 of the inner race 20, or grooves may be formed on both surfaces.

Means for firmly engaging the mounting member 40 with the shaft 10 or the inner race 20
As a means for firmly engaging the mounting member 40 with the mounting member 40, an appropriate means can be selected from interference of a fitting surface, screws, adhesion, welding, keys, and the like.

In the first invention, the load applied to the inner ring 20 is transmitted to the shaft 10 via the mounting member 40.
When the operation is performed under a higher or lower temperature environment than the time of mounting, the stress (fitting surface stress) acting on each fitting surface of the inner ring 20, the mounting member 40 and the shaft 10 is as follows.

When operating in a high temperature state, the difference in the linear expansion coefficient between the mounting member 40 and the shaft 10 and the inner race 20 causes the shaft 10 of the mounting member 40 to move.
The interference between the inner ring 20 and the inner ring 20 increases with the temperature rise. However, of these mating surfaces,
On the mating surface on the side where 13 is not formed, the mounting member
Since the coefficient of linear expansion of 40 is an intermediate value between the shaft 10 and the inner ring 20, the increase in interference due to the temperature rise is caused when the inner ring 20 is fitted to the shaft 10 without using the mounting member 40. It can be suppressed to a smaller ratio. Further, in the fitting surface on the side where the groove 13 is formed, the elastic deformation amount with respect to the load is much larger than in the case where the groove 13 is not formed, and the apparent spring constant of the convex portion 14 is small. Increase in interference due to temperature rise
Is much smaller than in the case where no is formed.

By combining the above operations, it is possible to prevent the fitting surface stress from exceeding the breaking stress of the inner ring 20 and increasing.

When operating in a low temperature state, the difference in the linear expansion coefficient between the mounting member 40 and the shaft 10 and the inner race 20 causes the shaft 10 of the mounting member 40 to move.
The interference between the inner ring 20 and the inner ring 20 is reduced in accordance with the temperature drop. However, also in this case, for the same reason as in the case of the high temperature state described above, the decrease in the fitting surface stress is much smaller than in the case where the mounting member 40 is not interposed and the case where the groove 13 is not formed, It becomes possible to prevent the occurrence of creep.

Instead of the spiral groove 13 of the above embodiment, a circumferential groove 13
May be formed at an appropriate pitch. The spiral groove 13 is not limited to a single groove, and may be formed as a multiple groove.

The spiral groove is easier to process and manufacture than the circumferential groove, and even if a large temperature difference occurs so that the interference between the shaft 10 and the inner ring 20 disappears. Since wear due to creep occurs uniformly in the axial direction, it has the advantage of not causing deep scratches at specific locations and reducing the degree of damage, making it more practical than circumferential grooves Great nature.

Further, the cross-sectional shape of the groove 13 in FIG. 1 is formed in an arc shape.
It is possible to select the optimum shape such as trapezoidal shape, square shape, etc. as necessary. Furthermore, the depth, width, axial interval (pitch), etc. of the groove 13 are also set to the optimum values as necessary. Can be selected.

In the second invention, the linear expansion coefficient of the
When the coefficient of linear expansion is made substantially equal to 20, a spiral groove 13 is formed on the outer peripheral surface 12 of the shaft 10 as in the first invention, and a convex portion between the grooves 13 is formed. 14, mounting member 40
The inner peripheral side fitting surface 41 of the inner ring 20 is fitted with an interference, and the inner peripheral side fitting surface 21 of the inner ring 20 is firmly engaged with the outer peripheral surface 42 of the mounting member 41 for mounting.

Contrary to the above, when the linear expansion coefficient of the mounting member 40 is substantially equal to the linear expansion coefficient of the shaft 10, the outer peripheral surface of the mounting member 40
A groove is formed in 42, and the inner ring is
The inner peripheral side fitting surface 41 of the mounting member 40 may be firmly engaged with the outer peripheral surface 12 of the shaft 10 for mounting.

In each of the above mounting structures, instead of forming a groove on the outer peripheral surface 12 of the shaft 10, a groove may be formed on the inner peripheral side fitting surface 41 of the mounting member 40, or a groove may be formed on both surfaces. Often,
Instead of forming a groove on the outer peripheral surface 42 of the mounting member 40, a groove may be formed on the inner peripheral side fitting surface 21 of the inner race 20, or grooves may be formed on both surfaces.

As means for firmly engaging the mounting member 40 or the inner ring 20 with the shaft 10 or the mounting member 40, respectively, the means described in the first invention can be appropriately selected.

In the second invention, the load applied to the inner ring 20 is transmitted to the shaft 10 via the mounting member 40.
Is operated in an environment of a higher or lower temperature than that at the time of mounting, the stress (fitting surface stress) applied to each fitting surface of the inner ring 20, the mounting member 40 and the shaft 10 is as follows.

When operating in a high temperature state, the load applied to the inner ring 20 is caused by a temperature rise between the mounting member 40 and either the shaft 10 or the inner ring 20 having a linear expansion coefficient substantially equal to that of the mounting member 40. Since there is almost no increase in interference, the transmission is performed without increasing the fitting surface stress. Mounting member 40
Then, at each fitting surface with either the shaft 10 or the inner ring 20 whose linear expansion coefficient is not equal to that of the mounting member 40, the interference increases according to the temperature rise. However, in this fitting surface, since the same action as the elastic deformation action by the groove 13 formed in at least one of the fitting faces described in the first invention works, the increase in interference due to the temperature rise is reduced. Since it is much smaller than the case where the groove 13 is not formed, it is possible to prevent the fitting surface stress from exceeding the breaking stress of the inner ring 20 and increasing.

When operating in a low-temperature state, the load applied to the inner race 20 is caused by a temperature drop between the mounting member 40 and either the shaft 10 or the inner race 20 having a linear expansion coefficient substantially equal to that of the mounting member 40. Since the interference is hardly reduced, the stress is transmitted without reducing the fitting surface stress. Mounting member 40
In each of the fitting surfaces with either the shaft 10 or the inner ring 20 whose linear expansion coefficient is not equal to that of the mounting member 40, interference decreases according to the temperature drop. However, also in this case, for the same reason as in the case of the high temperature state described above, the decrease in the fitting surface stress is much smaller than in the case where the mounting member 40 is not interposed and the case where the groove 13 is not formed. , It is possible to prevent the occurrence of creep.

In the present invention, a circumferential or spiral groove is formed on at least one of the fitting surfaces of the inner ring and the shaft of the rolling bearing as in the above-described embodiment.
If an axial groove different from this is formed, the bending stress is repeatedly applied to the inner ring with the passage of the rolling elements, and the tensile stress on the inner peripheral side fitting surface increases, so that the inner ring is easily broken. Inconvenience occurs.

〔The invention's effect〕

As described above, according to the first aspect, the shaft and the inner ring mounted on the shaft via the mounting member have different linear expansion coefficients, and the mounting member has an intermediate value of the linear expansion coefficient between the shaft and the inner ring. In the case of having, even if the interference between the fitting surface between the shaft and the mounting member, and the fitting surface between the mounting member and the inner ring is changed due to a temperature change between the time of mounting and the time of use, The load applied to the inner ring, of the fitting surface of the mounting member and the shaft and the inner ring,
On the mating surface on which the groove is formed, since the light is transmitted by the convex portion between the groove and the groove, the change in the fitting surface stress can be absorbed by the elastic deformation of the convex portion, On the mating surface on which the groove is not formed, the difference in linear expansion coefficient between the mounting member and the shaft or the inner ring is smaller than the difference in linear expansion coefficient between the inner ring and the shaft. Changes are mitigated. Therefore, as a result of the above, it is possible to prevent the inner ring from being broken due to an increase in the mating surface stress at a high temperature, or the inner ring from being vibrated or worn due to creep caused by a decrease or disappearance of the mating surface stress at a low temperature. Will be possible.

Further, in the case where a spiral groove is formed on at least one of the fitting surfaces of the mounting member, the shaft, and the inner ring, and the groove is mounted, even if creep occurs, only the damage of the inner ring becomes slight. In addition, an advantage that processing and manufacturing can be easily performed can be obtained.

Further, the specifications such as the shape and dimensions of the groove formed in the fitting surface between the mounting member and the shaft or the inner ring can be freely selected and designed so as to be optimal as required. It does not require any other mounting members that require special processing for mounting, so it does not require any skill in mounting, it can not only facilitate accurate centering, but also has a simple configuration and more reliable mounting The structure is obtained.

Furthermore, according to the first invention, since the mounting member is interposed, there is obtained an advantage that it can easily cope with long-term use or replacement of parts due to other causes.

According to the second aspect, the shaft and the inner ring mounted on the shaft via the mounting member have different linear expansion coefficients, and the mounting member has a value substantially equal to the linear expansion coefficient of one of the shaft and the inner ring. If the interference between the fitting surface between the shaft and the mounting member or the fitting surface between the mounting member and the inner ring changes due to a temperature change between the mounting and the use, the inner ring The applied load is transmitted by the convex portion between the grooves on the fitting surface on the side where the groove is formed among the respective fitting surfaces of the mounting member, the shaft and the inner ring. The change in the stress of the fitting surface can be absorbed by the elastic deformation of the convex portion, and the coefficient of linear expansion between the mounting member and the shaft or the inner ring is substantially equal on the fitting surface on the side where no groove is formed. In addition, there is almost no change in fitting surface stress due to temperature change. Therefore, also in the second invention, it is possible to prevent the inner ring from being broken due to an increase in the fitting surface stress at a high temperature, or the vibration and abrasion of the inner ring from being creeped due to the decrease or disappearance of the fitting surface stress at a low temperature. While being possible, the advantages of the second and subsequent stages described in the first invention are also obtained.

[Brief description of the drawings]

FIG. 1 is a vertical side view of an upper half showing an embodiment in which the present invention is applied to a ball bearing, and FIG. 2 is a vertical side view showing a mounting structure of a conventional cylindrical roller bearing. In the figure, 10 is the shaft, 12 is the outer peripheral surface of the shaft, 13 is the groove, 20 is the inner ring, 21
Is an inner peripheral fitting surface of the inner race, 40 is a mounting member, and 41 and 42 are an inner peripheral fitting surface and an outer peripheral surface of the mounting member, respectively.

Claims (2)

(57) [Claims] 1. A mounting member having a coefficient of linear expansion different from that of a shaft and an inner ring mounted on the outer periphery of the shaft and having a linear expansion coefficient intermediate between the coefficients of linear expansion of the shaft and the inner ring. One of the fitting surface between the mounting member and the inner ring and the fitting surface between the mounting member and the shaft are firmly engaged by the engagement means, and at least one of the other fitting surfaces On the other hand, an inner ring mounting structure provided with grooves formed in the circumferential direction at intervals in the axial direction, or grooves formed in a single or multiple spiral shape. 2. A linear expansion coefficient which is substantially equal to one of the shaft and the inner ring between the shaft and an inner ring which has a different linear expansion coefficient from the shaft and which is attached to the outer periphery of the shaft. The fitting surface between the mounting member and the shaft or inner ring having substantially equal linear expansion coefficients is firmly engaged by the engagement means, and the mounting member and the inner ring or shaft having unequal linear expansion coefficients are fitted. A groove formed in the circumferential direction at an interval in the axial direction, or a groove formed in a single or multiple spiral shape is provided on at least one of the fitting surfaces of the inner ring. Mounting structure.