JPH02217613A - Attachment device for annular body - Google Patents

Abstract

PURPOSE:To make it easier to assemble an annular body of different coefficient of linear expansion from that of its partner member and also prevent abrasion and breakage by attaching the annular body at such a size that the engaging faces of the annular body with respect to the partner member and an intermediate spacer are put in firm engagement when in use and that the load and maximum stress of the annular body are smaller than the allowable maximum stress of the component material of the annular body. CONSTITUTION:An annular body 20 attached to a partner member 10 by an attaching device is put in firm engagement with both the partner member 10a and a spacer 40 at latest when it is operated, so that loads exerted thereon are distributed to both the annular body 20 and the spacer 40 and transmitted from the annular body 20 to partner member 10 or from the partner member 10 to annular body 20. Besides, because the annular body 20 has its engaging faces 21, 23 each set such that the maximum stress which may be generated by loads exerted thereon, the above engagement and temperature changes is smaller than the allowable maximum stress of the component material, the annular body 20 can support the loads without being broken. Also, when a taper face is formed on the end face 22 of the annular body 20 in its axial direction and an intermediate spacer is sandwiched and fixed between the annular body 20 and the spacer 40, the loads are transmitted by the intermediate spacer as well as by the annular body 20 and spacer 40.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is based on the invention, in which the linear expansion coefficients of an annular body, such as an inner ring or an outer ring of a bearing, and a mating member such as a shaft or an axle box to which this annular body is attached are different. The present invention relates to a mounting device for an annular body in a case.

[Conventional technology]

Conventionally, as a mounting structure when the linear expansion coefficients of the bearing and the mating member to which it is attached differ, an article on rolling bearings as shown in Fig. 3 has been published by LUBRICATI.
Published in ON ENGINEERING July 1981 issue, pages 407-415.

The inner ring 2 of this bearing is attached to the shaft 1, the outer ring 3 is attached to an axle box (not shown), and cylindrical rollers 5 with cages 6 are disposed between the inner ring 2 and the outer ring 3. 1 is made of steel, and the inner ring 2 is made of ceramic. Both end surfaces in the axial direction of the inner ring 2 are tapered surfaces that expand outward in diameter with respect to the center axis, and are fitted to the shaft 1 with a clearance fit. It is sandwiched between a pair of spacers 4°4 made of steel that are fitted together, and when the shaft 1 and the spacers 4, 4 thermally expand, the inner ring 2 slides relatively on both end surfaces. This prevents excessive load from being applied.

[Problem to be solved by the invention]

In the above-mentioned rolling bearing, the load applied to the bearing is magnified by the wedge action of both end faces of the inner ring 2, and
, 4, the contact pressure on both end surfaces of the inner ring 2 increases significantly and causes wear.

Inconveniences such as breakage or destruction due to the applied load reaching the limit may occur, and there is a problem that the upper limit of the applied load is restricted to a small value.

Furthermore, when assembling the inner ring 2 and the spacers 4, 4 onto the shaft 1, since the inner ring 2 is a loose fit, relative slippage occurs between the inner ring 2 and the spacers 4, 4, resulting in accurate alignment. It is difficult to remove the product, and assembly requires W1 training, which poses a problem in terms of workability.

The present invention solves the above-mentioned problems, enables accurate assembly of a mating member and an annular body having a coefficient of linear expansion different from that of the mating member, and enables operational use of the annular body assembled to the mating member. It is an object of the present invention to provide a mounting device that does not cause wear or damage to the annular body inside.

[Means for Solving the Problems] In the present invention, in order to achieve the above object, the annular body fitted on the outer periphery or the inner periphery of the mating member has a linear expansion coefficient different from that of the mating member, Both end surfaces of the annular body in the axial direction are clamped by a pair of spacers that fit into the circumferential surface of the annular body on the opposite side of the mating surface with the mating member and firmly engage with the outer or inner circumference of the mating member. A mounting device comprising:
The mating surfaces of the annular body and the spacer are tightly fitted at the latest during operation of the annular body, and the maximum stress due to the load applied to the annular body, this fitting, and temperature change is The annular body is attached to a mating member with dimensions set to be smaller than the maximum allowable stress of the constituent material of the annular body.

The coefficient of linear expansion of the material forming the spacer may be the same as or different from the coefficient of linear expansion of the material forming the annular body.

At least one end surface in the axial direction of the annular body may be formed into a tapered surface, and an intermediate spacer having an opposing end surface having the same taper angle as the annular body may be sandwiched between this axial end surface and the spacer. .

This intermediate spacer may be tightly engaged with the circumferential surface of the opposite side of the surface to which the mating member is fitted, or may be fixed integrally with the spacer.

The tapered surface formed on the axial end face of the annular body is preferably set at an angle that has a predetermined relationship between the axial length and the diameter at the center of the thickness of the annular body.

When this invention is applied to a bearing ring of a rolling bearing, the axial end of the spacer can be used as a guide collar for the rolling elements of the rolling bearing, and can also be used as a guide ring for the cage of the rolling elements. Can be done.

[Effect]

The annular body attached to the mating member by the mounting device of the present invention is firmly fitted to the mating member and the spacer at the latest during operation, so that the applied load is transferred between the annular body and the spacer. It is divided and transmitted from the annular body to the mating member or from the mating member to the annular body.

Moreover, the dimensions of each fitting surface of the annular body are set so that the applied load and the maximum stress generated by this fitting and temperature change are smaller than the maximum allowable stress of the constituent materials. The body can carry loads without breaking.

Further, when a tapered surface is formed on the axial end face of the annular body and an intermediate spacer is sandwiched between the annular body and the spacer, the load is transmitted by the intermediate spacer in addition to the annular body and the spacer.

In addition, if the angle of the tapered surface formed on the axial end face of the annular body is set to have a predetermined relationship with the axial length and diameter at the center of the thickness of the annular body, the annular shape may change due to temperature changes. It is possible to prevent the influence of thermal stress generated between the body and the mating member.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an embodiment in which the present invention is applied to the assembly of an inner ring (annular body) and a shaft (a mating member) of a cylindrical roller bearing. This cylindrical roller bearing has an outer ring 30. Inner ring 20 and outer ring 30
The cylindrical roller 50 is arranged between the inner ring 20 and the cylindrical roller 50, and the cylindrical roller 50 is held and guided by a cage 51 and transferred.

The constituent material of the outer ring 30 of the above-mentioned cylindrical roller bearing is ordinary bearing steel, but the inner ring 20 is made of a ceramic material such as silicon nitride, and its linear expansion coefficient αj is equal to that of the shaft 10 made of steel. It is smaller than the linear expansion coefficient α8 of .

The inner ring 20 is attached with its inner circumferential fitting surface 21 fitted to the shaft lO, and vertical surfaces formed on both axial end surfaces 22 thereof being sandwiched and supported by a pair of spacers 40.

Each spacer 40 has an annular portion 40a that fits on the outer peripheral surface of the shaft 10.
and a cylindrical portion 40b that protrudes in the axial direction from the annular portion 40a and fits into the outer peripheral side fitting surface 23 of the inner ring 20,
The annular portion 40a is fitted onto the shaft 10 by tight fitting, or by adhesive bonding. Securely held by 8 contacts, screw fastening, etc.
are doing.

The opposite end surfaces 22 of the inner ring 20 and the opposing end surfaces of each spacer 40 supporting the inner ring 20 are not limited to being in contact with each other, but may be opposite to each other with an appropriate axial clearance therebetween.

Regarding the fit of the inner ring 20 to the shaft lO and the fit of the spacer 40 to the cylindrical portion 40b, the shaft 10. Appropriate conditions are set depending on the linear expansion coefficients of the constituent materials of the inner ring 201 and the spacer 40, the temperature difference between installation and use, and each dimension.

Now, as in this embodiment, the inner ring 20 is made of ceramic material (linear expansion coefficient α), and the shaft 10 is made of steel (linear expansion coefficient α).
3), the spacer 40 is made of a material that has the same coefficient of linear expansion as the inner ring 20, or a material that has a coefficient of linear expansion larger than that of the inner ring 20, such as steel, brass, or a combination of ceramic and metal materials. Assuming that the bearing is made of a composite material (linear expansion coefficient αk) and the temperature T when the bearing is in use is higher than the temperature T1 when the bearing is installed, the inner fitting surface of the inner ring 20 The fit between the inner ring 21 and the shaft 10 is a loose fit when the bearing is installed, but it is a tight fit when the bearing is used.
The outer circumferential fitting surface 23 of No. 0 fits into the cylindrical portion 40b of the spacer 40 by interference fit when the bearing is mounted.

In other words, the inner ring 20 at the time of bearing installation (temperature T)
Diameter clearance between and shaft 10 (fitting clearance)
When Δd is the diametrical tightening margin between the inner ring 2o and the cylindrical portion 40b of the spacer 4o, d is the diameter (inner diameter, outer diameter) of each fitting surface 21, 23 of the inner ring 20, respectively. D, when the bearing is in use (temperature T), the inner ring 2
The clearance decreases on the inner peripheral side fitting surface 21 of o, and becomes (α, -
αJ)(TbT-)d-Δd, and the interference on the outer fitting surface 23 of the inner ring 2o is ΔD-(α, -α,) ('r, -'r, ) D
decreases in amount.

At this time, the maximum tensile stress σ and X on the inner fitting surface 2 of the inner ring 20 are the maximum tensile stress caused by the tightening between the inner ring 20 and the shaft 10, and the maximum tensile stress when a load is applied to the bearing. The maximum compressive stress σcs*x on the outer peripheral side fitting surface 23 of the inner ring 20 is the sum of the maximum tensile stress generated in It is the sum of the maximum compressive stress that occurs, the maximum compressive stress that occurs when a load is applied to the bearing, and the maximum compressive stress that occurs due to temperature changes.

Therefore, the dimensions of the fitting surface 21.23 of the inner ring 20 with respect to the shaft 10 and the spacer 40 are determined based on the linear expansion coefficient α4. α1. α, and the temperature T when the bearing is installed and in use,
, T, and if the allowable tensile stress of the constituent material of the inner ring 20 is σa and the allowable compressive stress is biwa, then the following (1
) or 4) so that the formula holds true.

ΔD>(α, -α,)(T, -T,)D...(1)Δ
d<(α, −αj) ('rb −'r, ) c+
...(2) σt, □〈σ7
・・・・・・(3) σC1□〈σ,
(4) With the above configuration, the inner ring 20 does not break due to the load applied to the bearing, and only a portion of the load is applied to the shaft 10 through the inner fitting surface 21 of the inner ring 20. At the same time, the remaining portion of the load is also transmitted by each spacer 40 via the outer circumferential fitting surface 23. The load acting on the bearing in this way is transmitted from the inner ring 20 to the shaft 10 (or from the shaft 10 to the inner ring 20) with the inner ring 20 and each spacer 40 sharing the load. Inner ring 2
0 through the inner circumferential side fitting surface 21 or through the outer circumferential side fitting surface 2
The shared load through 3 is reduced.

For this reason, the maximum allowable load on the bearing increases, but the allowable tensile stress σ and allowable compressive stress σ of the ceramic material that is the constituent material of the inner ring 20. The transmission load on each fitting surface 21.23 is set to the optimum value according to the value of
The configuration may be such that the total transferable load is maximized.

Note that in this embodiment, the cylindrical portion 40b of the spacer 40
The end surface of the axial end portion 4 of the cylindrical roller 50 is closely opposed to the end surface of the cylindrical roller 50, and also functions as a guide collar for the cylindrical roller 50, and the outer diameter surface of the axial end portion 41 of the cage It also functions as a guide ring for the retainer 51, facing closely to the inner diameter surface of the retainer 51. Only one of these functions may be combined.

FIG. 2 shows an embodiment in which the present invention is applied to the assembly of an inner ring (annular body) and a shaft (a mating member) of a ball bearing. This ball bearing has an outer ring 30. It is composed of an inner ring 2o and balls 53 held and guided by a retainer 54, and similarly to the cylindrical roller bearing shown in FIG. Inner ring 2
A pair of spacers 40 that tightly engage the shaft lo are fitted into the outer peripheral side fitting surfaces 23 at both axial end portions of the shaft lo. Inner ring 2
The fitting conditions for the shaft 10 and the spacer 40 and the dimensions of the fitting surfaces 21 and 23 are also set in the same manner as in the configuration of the embodiment shown in FIG.

In this embodiment, both end surfaces 22 of the inner ring 20 in the axial direction expand in diameter in the outward opening direction with respect to the central axis, and have an inclination angle of θ1. A pair of intermediate spacers 45 formed on a tapered surface having an angle of θ2 and having opposing end surfaces having the same inclination angle as the end surfaces 22 on both sides are disposed between the inner ring 20 and the spacer 40, and the inner ring 20 is sandwiched between them.

This intermediate spacer 45 is made of a material having the same coefficient of linear expansion as the shaft 10.

According to this embodiment, the load acting on the bearing is
Not only can the spacers 40 and 40 share the load, but also the load shared by the intermediate spacer 45 can be transmitted to the shaft 10 via the end surfaces 22 on both sides of the inner ring 20. Also, the load shared via the inner fitting surface 21 of the inner ring 20 or via the outer fitting surface 23 is reduced.

The above-mentioned intermediate spacer 45 can be installed not only by the illustrated mounting method, but also by firmly engaging the intermediate spacer 45 with the shaft 10, and then tightly fitting the spacer 40 onto the outer peripheral surface of the intermediate spacer 45 itself. Alternatively, the intermediate spacer 45 and the spacer 40 may be joined and fixed together to fit the spacer 40 to the outer fitting surface 23 of the inner ring 20.

In this embodiment, when the intermediate spacer 45 has the same coefficient of linear expansion as the shaft 10, the inclination angle θ1. By setting θ as shown below, when the temperature changes between when the bearing is installed and when it is in use, the contact surface between the inner ring 20 and the intermediate spacer 45, and the fitting surface between the inner ring 20 and the shaft 10 It is possible to prevent the effects of thermal stress that occurs in

That is, the axial length of the inner ring 20 at the center of wall thickness is W
P and the diameter is ri, then the axial length change ΔXI+ΔX2 of both end surfaces 22 due to temperature change ΔT, and the radial length change Δy1. Δy2 is as follows. The conditions when there is no relative change in length in the axial and radial directions are: Since 1, α, ≠ αj, ΔT≠0, the above formula 1% θ1. θ2 is positive when the diameter of the tapered surfaces of both end faces 22 of the inner ring 20 expands in the direction of outward opening as shown in the figure, and negative when, on the contrary, the diameter decreases in the direction of opening inward.

The intermediate spacer 45 may sandwich only one axial end surface of the inner ring 20.

In the above embodiment, a case has been described in which an inner ring made of a ceramic material is attached to a shaft made of a steel material, but the present invention is not limited to such a case. The same can be applied to the case where it is attached to a shaft made of material.

Furthermore, the present invention can be applied not only to bearings in which the inner ring and the shaft have different coefficients of linear expansion (but also to bearings in which the outer ring and the axle box have different coefficients of linear expansion).

Furthermore, the present invention is applicable not only to cases where the temperature during use of the bearing is higher than the temperature at the time of installation, but also to cases where the temperature during use of the bearing is lower than the temperature at the time of installation.

Furthermore, the present invention can be applied not only to rolling bearings but also to the case where an annular body constituting a sliding bearing or other device is attached to a mating member.

〔Effect of the invention〕

As explained above, according to the present invention, when the linear expansion coefficient of the annular body is different from that of the mating member, the load applied to the annular body is transferred between the fitting surface of the annular body itself and the mating member. Since the load can be shared and transmitted to the mating member via the fitting surface to the seat, the load that can be transmitted increases, and if the same transmitted load is used, the durability life becomes longer. In particular, when the axial end face of the annular body is formed into a Taber surface and an intermediate spacer is provided between the annular body and the spacer,
Since the load can also be shared through the end face of the intermediate spacer, the above effect is further improved.

Further, when the tapered surface of the axial end face of the annular body is set at a predetermined angle, concentration of thermal stress due to temperature changes can be prevented.

Furthermore, according to the present invention, when installing the annular body, it is possible to reduce the fitting clearance with respect to the mating member, which not only facilitates centering during installation, but also
Even during operation, concentricity with respect to the mating member can be maintained with high precision, the high performance of the attached device is maintained, and a highly reliable attachment device can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional side view of the upper half of an embodiment in which the present invention is applied to a cylindrical roller bearing, and FIG. 2 is a vertical cross-sectional side view of the upper half of an embodiment in which the present invention is applied to a ball bearing. FIG. 3 is a vertical cross-sectional side view of the upper half of the conventional cylindrical roller bearing showing how it is mounted. In the figure, 10 is the shaft (mating member), 2Q is the inner ring (annular body),
21 is the inner peripheral side fitting surface of the inner ring, 22 is the axial end surface of the inner ring,
23 is a fitting surface on the outer peripheral side of the inner ring, and 40 is a spacer.

Claims (5)

[Claims] (1) The annular body fitted to the outer or inner circumference of the mating member has a linear expansion coefficient different from that of the mating member, and the annular body is fitted to the peripheral surface of the annular body on the opposite side of the mating surface with the mating member. A mounting device in which both end surfaces of an annular body in the axial direction are sandwiched between a pair of spacers that are fitted together and tightly engaged with the outer periphery or inner periphery of a mating member, the mounting device comprising: The mating surfaces of the annular body should be in a hard fitted state at the latest when the annular body is in operation, and the maximum stress due to the load applied to the annular body, this fitting, and temperature changes must be greater than the allowable maximum stress of the constituent materials of the annular body. 1. A mounting device for an annular body, characterized in that the annular body is attached to a mating member with dimensions set such that the annular body is also small. (2) At least one end surface in the axial direction of the annular body is a tapered surface, and an intermediate spacer having an opposite end surface at the same angle as the tapered surface is sandwiched between the annular body and the spacer ( 1) A mounting device for the annular body described above. (3) Claim (2) in which the spacer firmly engages with the circumferential surface of the intermediate spacer on the side opposite to the fitting surface with the mating member, or the spacer and the intermediate spacer are integrally fixed. ) mounting device for the annular body. (4) The angles θ_1 and θ_2 with respect to the axis-perpendicular cross section of both end faces in the axial direction of the annular body are positive when they open outward with respect to the central axis, and negative when they open inward, and the axis at the thickness center of the annular body. The annular body attachment device according to claim 2 or 3, wherein the relationship between the direction length W_P and the diameter D_P is set as tanθ_1+tanθ_2=2W_P/D_P. (5) The annular body is a bearing ring of a rolling bearing, and the axial end of the spacer fitted into the bearing ring has at least one of the functions of a guide collar for the rolling elements and a guide ring for the cage. The annular body attachment device according to any one of claims (1) to (4).