JP2000074053A - Bearing support device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing support device capable of properly adjusting a preload applied on each of bearings without strictly controlling tightening torque of a nut to fix a pair of the bearing on a shaft. SOLUTION: Each of outer rings 14b, 16b of a pair of conical roller bearing 14, 16 installed on a shaft 12 is respectively fitted in a ring recessed part 10a formed on an elastic structural body 10. In this state, a nut 22 is screwed on a male screw part 12b of the shaft 12, and inner rings 14a, 16b of the both bearings 14, 16 and a plural number of spacers 18, 20 are fixed on the shaft 12. A specified preload is loaded in the axial direction on each of the bearings 14, 16 under elastic restoring force of the elastic structural body 10 when a clearance between the inner rings 14a, 16a of the both roller bearings 14, 16 is fine-adjusted by adjusting tightening torque of the nut 22. Fluctuation of the preload to each of the conical roller bearings 14, 16 caused by dispersion of the tightening torque of the nut 22 is effectively reduced by elastic deformation of the elastic structural body 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing support structure and, more particularly, to a bearing support device for supporting a pair of bearings mounted on a shaft in a state where a load is applied to the bearings in an axial direction.

[0002]

2. Description of the Related Art A bearing capable of applying a radial load and a unidirectional thrust load, such as a tapered roller bearing and a single-row angular contact ball bearing, usually has two bearings arranged opposite to each other along an axis.
Used in a state where thrust loads in both directions can be applied.
These two bearings are supported by a bearing support in the mechanical structure. At this time, generally, by adjusting the distance between the inner rings or the outer rings of the two bearings in the axial direction, a predetermined axial direction is applied to each bearing. Preload is applied. Such a preload is effective for preventing the bearing gaps of the bearings from fluctuating due to an external force, and for preventing the bearings from being misaligned particularly during high-speed rotation.

FIG. 4 shows an example of this type of conventional bearing and bearing support structure. In the illustrated example, a pair of tapered roller bearings 2 and 3 are attached to the shaft 1 so as to face each other. Axis 1
Is provided with an overhang portion 1a for supporting the inner ring 2a of one tapered roller bearing 2, a male screw portion 1b at the shaft end, and an inner ring 3a of the other tapered roller bearing 3 disposed adjacent to the male screw portion 1b. Is done. These tapered roller bearings 2, 3 are arranged in a so-called back-to-back combination type, and each inner ring 2a,
A plurality of spacers 4 and 5 for maintaining the interval between the inner rings 2a and 3a are provided between the inner rings 3a.

[0004] The shaft 1 is received in a non-contact manner in a hole 6a formed through a bearing support 6 in the mechanical structure. Each outer ring 2b, 3b of the pair of tapered roller bearings 2, 3 is
Are respectively fitted into annular concave portions 6b formed at both ends of the hole 6a. In this state, the nut 7 is screwed onto the male screw portion 1b of the shaft 1, and the inner rings 2a, 3a of the bearings 2, 3 and the plurality of spacers 4, 5 are fixed to the shaft 1.

The distance between the inner rings 2a, 3a of the double tapered roller bearings 2, 3 is defined by the axial dimension of the spacers 4, 5. On the other hand, the outer ring 2 of the double tapered roller bearings 2 and 3
b, the distance between the two annular recesses 6b of the bearing support 6
It is defined by the distance between them. Therefore, when the nut 7 is screwed onto the shaft 1, the total dimension in the axial direction of the plurality of spacers 4 and 5, that is, the double tapered roller bearing, is such that a predetermined preload is applied to each of the bearings 2 and 3 in the axial direction. 2, 3 inner rings 2
The target value of the interval between a and 3a is set. These spacers 4 and 5 are used together with the cylindrical spacer 4 having an axial dimension somewhat shorter than the target value so that the total dimension in the axial direction can be easily adjusted. Annular spacer (or shim) 5 with small axial dimension
It is composed of

[0006]

In the conventional bearing support structure described above, when the total axial dimension of the plurality of spacers 4, 5 becomes larger than the target value, a predetermined preload can be applied to each of the bearings 2, 3. Disappears. Therefore, usually, one cylindrical spacer 4 and a desired number of annular spacers 5 are used by being stacked on the shaft 1 in the axial direction until their total dimension approaches the target value. In this case, it is difficult to make the total dimension of the plurality of spacers 4 and 5 in the axial direction exactly match the target value. Therefore, the distance between the inner rings 2 a and 3 a of the double tapered roller bearings 2 and 3 and the spacers 4 and 5 is difficult. Usually, a slight gap is left. By adjusting the tightening torque of the nut 7, the inner ring 2 of the double tapered roller bearings 2, 3 around the target value is adjusted.
a, 3a is finely adjusted to apply a predetermined preload to the bearings 2, 3 in the axial direction.

However, at this time, excessive tightening torque is applied due to insufficient adjustment of the tightening torque of the nut 7, and the gap between the inner rings 2a, 3a of the double tapered roller bearings 2, 3 and the spacers 4, 5 is reduced more than necessary. Then, since the distance between the outer rings 2b, 3b of the double tapered roller bearings 2, 3 does not substantially decrease due to the structure of the bearing support 6, the preload applied to each bearing 2, 3 becomes excessive, and the shaft rotation At times, there is a fear that damage such as seizure of the rolling elements (rollers) may occur. On the other hand, if the tightening torque of the nut 7 is too small, the preload applied to the tapered roller bearings 2 and 3 becomes insufficient, and the bearing gap between the bearings 2 and 3 is easily enlarged by the thrust load at the time of rotating the shaft, thereby stabilizing the bearing. There is a concern that the shaft support may become difficult. Moreover, in this case, even a small variation in the tightening torque of the nut 7 easily changes the preload on each bearing. Therefore, in the above configuration, it is essential to strictly control the tightening torque of the nut 7.

[0008] However, in order to strictly control the tightening torque of the nut, there is a problem that the cost of equipment such as a tightening device generally rises. However, it is difficult to strictly control the tightening torque with a relatively inexpensive impact wrench. Therefore, conventionally, by improving the dimensional accuracy of the spacer disposed between the two bearings, in particular, the annular spacer (shim) for adjusting the gap, and by making the total axial dimension of the plurality of spacers as close as possible to the target value, Measures have been taken to appropriately adjust the preload applied to each bearing while suppressing the rise in capital investment costs. However, it is difficult to improve the dimensional accuracy of the spacer to the extent that fluctuations in the preload due to variations in the tightening torque of the nut can be eliminated, and it is not possible to cope with further higher performance of the bearing function.

An object of the present invention is a bearing support device for supporting a pair of bearings mounted on a shaft in a state where a preload is applied thereto, and strictly controlling a tightening torque of a nut for fixing the bearings to the shaft. There is no need to control, and the axial preload applied to each bearing can be adjusted appropriately without depending on the dimensional accuracy of the spacer that defines the distance between the bearings, thereby promoting higher performance of the bearing function An object of the present invention is to provide a bearing support device that can be used.

[0010]

In order to achieve the above object, according to the present invention, a pair of bearings mounted on a shaft are placed in a state where a load in an axial direction is applied to the bearings. Provided is a bearing support device for supporting, comprising: an elastic structure to which a fixed-side race of each of a pair of bearings is attached.

According to a second aspect of the present invention, in the bearing support device according to the first aspect, the elastic structure has an elastically deformable member having a free end and a fixed end, and the elastic structure has a fixed end. A supporting base, wherein the fixed side race of one bearing is mounted on a free end of the member, and the fixed side race of the other bearing is mounted on the base.

According to a third aspect of the present invention, there is provided the bearing support device according to the first or second aspect, further comprising at least one spacer disposed between the respective rotating races of the pair of bearings. A bearing support device is provided.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments with reference to the accompanying drawings. In the drawings, the same or similar components are denoted by common reference numerals. FIG. 1 conceptually shows a bearing support device according to the present invention. As shown in FIG. 1, the bearing support device according to the present invention includes:
It is characterized by comprising an elastic structure 10 to which each fixed-side bearing ring of a pair of bearings attached to a shaft is attached.

As in the prior art shown in FIG. 4, the shaft 12 has an inner ring 1 of one tapered roller bearing 14 adjacent to the overhang 12a.
4a, that is, the rotating raceway is attached, and the inner race 16 of the other tapered roller bearing 16 is adjacent to the male screw portion 12b at the shaft end.
a, ie, the rotating raceway is mounted. These tapered roller bearings 14 and 16 are arranged in a so-called back-to-back combination type, and the two inner rings 1 are provided between the respective inner rings 14a and 16a.
Plural spacers 1 for maintaining the interval between 4a and 16a
8, 20 are installed.

The outer races 14b and 16b of the pair of tapered roller bearings 14 and 16, that is, the fixed races, are formed in the elastic structure 10 so as to face outward in a direction away from each other.
0a. In this state, the nut 22 is screwed to the male screw portion 12b of the shaft 12, and the dual bearings 14, 16
Inner rings 14a, 16a and a plurality of spacers 18, 20 are fixed to the shaft 12.

The inner rings 14a of the double tapered roller bearings 14, 16
The distance between the spacers 16a is defined by the axial dimensions of the spacers 18 and 20. On the other hand, double tapered roller bearing 1
The distance between the outer races 4 b and 16 b of the fourth and 16 is defined by the distance between the two annular concave portions 10 a of the elastic structure 10. Therefore, when the nut 22 is screwed onto the shaft 12, each of the bearings 14, 1 under the elastic restoring force of the elastic structure 10
A target value of the total dimension in the axial direction of the plurality of spacers 18 and 20, that is, the distance between the inner rings 14 a and 16 a of the double tapered roller bearings 14 and 16 is set so that a predetermined preload is applied to the spacer 6 in the axial direction. . These spacers 18 and 20 have a cylindrical spacer 18 having an axial dimension somewhat shorter than a target value and are supplementarily used for the cylindrical spacer 18 to adjust the spacing so that the total axial dimension can be easily adjusted. And an annular spacer (or shim) 20 having a small axial dimension.

In the bearing support device according to the present invention, the outer races 14b and 16b of the double tapered roller bearings 14 and 16 are
Since it is elastically supported by 0, as described above,
A predetermined preload in the axial direction is applied to each of the bearings 14 and 16 in a state where the outer rings 14b and 16b of the double tapered roller bearings 14 and 16 approach each other due to the tightening of the nut 22 and the elastic structure 10 is flexed to some extent. Will be loaded. Therefore, when the total axial dimension of the plurality of spacers 18 and 20 is larger than the above-described target value, when the nut 22 is tightened, the inner rings 14a and 16 of the double tapered roller bearings 14 and 16 are formed.
Even if the elastic structure 10 is slightly bent in the range until the a comes into contact with the spacers 18 and 20, a predetermined preload cannot be applied to each of the bearings 14 and 16.

Therefore, in the same manner as in the prior art described above, one cylindrical spacer 18 and a desired number of annular spacers 20 are stacked on the shaft 12 in the axial direction until their total size approaches a target value. I do. In this case, the total axial dimension of the plurality of spacers 18 and 20 does not need to exactly match the target value, but may be stacked until an axial dimension somewhat smaller than the target value is obtained. Then, the nut 22 is tightened to bring the inner rings 14a, 16a and the outer rings 14b, 16b of the double tapered roller bearings 14, 16 closer to each other, and the elasticity is maintained in a range until the inner rings 14a, 16a come into contact with the spacers 18, 20. The structure 10 is bent. Here, nut 2
If the distance between the inner rings 14a and 16a of the double tapered roller bearings 14 and 16 is finely adjusted around the target value by adjusting the tightening torque of 2, the respective bearings can be adjusted under the elastic restoring force of the elastic structure 10. A predetermined preload is applied to the shafts 14 and 16 in the axial direction.

As described above, in the prior art, when the tightening torque of the nut 7 varies within an error range inherent in a general torque wrench, for example, and when the actual tightening torque becomes larger than a set value, the double tapered roller is used. While the inner rings 2a, 3a of the bearings 2, 3 approach each other in a range until they contact the spacers 4, 5, the outer rings 2b, 3b of the bearings 2, 3 cannot approach each other. Is subject to excessive preload. In order to prevent this, it is necessary to strictly control the tightening torque of the nut 7 or to improve the axial dimensional accuracy of the spacers 4 and 5.

On the other hand, according to the present invention, when the actual tightening torque of the nut 22 becomes larger than the set value due to an error, the inner rings 14a, 16 of the double tapered roller bearings 14, 16 are provided.
Even if a moves until it comes into contact with the spacers 18, 20, the outer rings 14b, 16b of the double tapered roller bearings 14, 16 can approach each other against the elastic restoring force of the elastic structure 10, so that each bearing Excessive preloads applied to 14 and 16 are avoided. That is, even if the tightening torque of the nut 22 varies within an error range inherent in, for example, a general torque wrench, the variation in the preload applied to the bearings 14 and 16 is reduced by the elastic deformation of the elastic structure 10. Because

As described above, according to the bearing support device of the present invention, the fluctuation of the preload on the tapered roller bearings 14 and 16 caused by the variation in the tightening torque of the nut 22 is reduced by the double tapered roller bearings 14 and 16. According to the configuration in which the distance between the outer rings 14b and 16b can be changed under the elastic deformation of the elastic structure 10, the distance between the inner rings 14a and 16a can be changed corresponding to the change in the distance between the inner rings 14a and 16a. Therefore, the preload applied to the tapered roller bearings 14 and 16 can be properly adjusted without strictly controlling the tightening torque of the nut 22.

In other words, in the bearing support device of the present invention, the effect of the variation in the tightening torque of the nut 22 on the variation of the preload on each of the tapered roller bearings 14 and 16 depends on the spacers 18 and 20, especially the annular shape. It is smaller than the effect of the axial dimensional change of the spacer 20. That is, the total axial dimension of the plurality of spacers 18 and 20 actually used is:
When the distance is smaller than the target value by a dimension close to one annular spacer 20 for adjusting the interval, the variation in the tightening torque of the nut 22 is large, and the inner rings 14a, 16a of the double tapered roller bearings 14, 16 are attached to the spacers 18, 20. , The fluctuation of the preload on each of the bearings 14 and 16 does not increase so much due to the elastic deformation of the elastic structure 10. In this case, the dimensional accuracy of the plurality of spacers 18, 20, particularly the annular spacer 20, which defines the distance between the bearings 14, 16 is slightly increased (to the extent sufficiently possible with the current technology), and the effect of preventing the fluctuation of the preload is obtained. It will be appreciated that is greatly improved.

FIG. 2 shows a bearing support device according to one embodiment of the present invention. This bearing support device is provided with a pair of tapered roller bearings 14 and 16 mounted on a shaft 12.
The elastic structure to which the members 4b and 16b are attached includes an elastically deformable attachment member 24 having a free end 24a and a fixed end 24b, and a base 26 supporting the attachment member 24 at the fixed end 24b. The other configuration is substantially the same as that shown in FIG.

The mounting member 24 has a bowl-like shape, and is fixed to the base 26 by a plurality of bolts 28 at a fixed end 24b formed in a flange shape on the outer peripheral edge. The free end 24a of the mounting member 24 defines a through hole 30 at the approximate center of the mounting member 24 for receiving the shaft 12 in a non-contact manner. The free end 24a of the mounting member 24 is formed with a sleeve portion 32 extending in a direction away from the base portion 26, whereby the through hole 3 is formed.
An outwardly facing annular recess 34 is formed adjacent to zero. A through-hole 36 is formed in the base 26 at a position overlapping the through-hole 30 of the mounting member 24 in the axial direction to receive the shaft 12 in a non-contact manner. An outwardly facing annular concave portion 38 is formed in the through hole 36 of the base portion 26 on a side away from the mounting member 24. Axis 12
Outer ring 14b of one tapered roller bearing 14 attached to
Is fitted in an annular recess 38 of the base 26, and the outer ring 16 b of the other tapered roller bearing 16 is attached to the annular recess 3 of the mounting member 24.
4.

In this embodiment, when the nut 22 is tightened, the inner ring 14 of the double tapered roller bearings 14 and 16 is closed.
As the a and 16a approach each other in a range until they come into contact with the plurality of spacers 18 and 20, the free end 24a side of the mounting member 24 on the base 26 is elastically bent as shown in FIG. , 16b are allowed to approach each other. Thus, by adjusting the tightening torque of the nut 22, each bearing 14, 14 under the elastic restoring force of the elastic structure 10
A predetermined preload can be applied to the shaft 16 in the axial direction.
The operation and effect of such a configuration are as described with reference to FIG.

In the above embodiment, an elastic member such as a spring may be interposed between the free end 24a of the mounting member 24 and the base 26. Thereby, the degree of elastic deformation of the elastic structure with respect to the variation in the tightening torque of the nut 22, that is, the degree of fluctuation of the preload on each of the bearings 14 and 16 can be appropriately changed. Further, the mounting member 24 itself can be formed from a spring.

FIG. 3 shows an example of an application form of the bearing support device according to the present invention. In this example, the bearing support device is a housing assembly 50 in the final reduction gear of the power transmission mechanism.
Are used for a pair of tapered roller bearings 54 and 56 for rotatably supporting the drive pinion 52.

In the illustrated final reduction gear, the housing assembly 50 includes a base 58 and a plurality (only one shown) of bolts 6.
A first mounting member 62 fixed to the base portion 58 by zero;
A second mounting member 66 fixed to the first mounting member 62 by a plurality (only one is shown) of bolts 64. One of the tapered roller bearings 54 attached to the shaft portion 52a of the drive pinion 52 has an outer ring 54a having a first attachment member 62.
Of the other tapered roller bearing 56
The outer ring 56a is formed in the annular recess 66 of the second mounting member 66.
a. A power transmission gear 68 is arranged between the tapered roller bearings 54 and 56. A nut 70 is screwed onto the axial front end of the shaft portion 52a of the drive pinion 52, and a pair of tapered roller bearings 54, 56 and a power transmission gear 6
8 is fixed to the shaft portion 52a, and each bearing 54, 56
Is adjusted so as to apply a preload.

In this case, a pair of tapered roller bearings 54, 56
The power transmission gear 68 disposed between the two has the function of the cylindrical spacer 18 described with reference to FIG. Therefore, in order to apply an appropriate preload to each of the bearings 54, 56, the annular spacer 20 for adjusting the distance described with reference to FIG. 1 is disposed between the tapered roller bearings 54, 56 and the power transmission gear 68. Further, the first mounting member 62 of the housing assembly 50 is configured as shown in FIG.
The second mounting member 66 corresponds to the mounting member 24 described with reference to FIG.

In such a configuration, the bearing support device according to the present invention is used for the pair of tapered roller bearings 54, 56 of the drive pinion 52 of the final reduction gear, which requires a high-performance bearing function. An appropriate preload can be applied by relatively easy and inexpensive means. As a result, the performance of the pair of tapered roller bearings 54 and 56 used for the drive pinion 52 is enhanced.

[0031]

As is apparent from the above description, according to the present invention, when a preload is applied to a pair of bearings mounted on a shaft, the tightening torque of a nut for fixing the bearings to the shaft is reduced. The preload in the axial direction applied to each bearing can be adjusted appropriately without the need for strict control, and without depending on the dimensional accuracy of the spacer that regulates the distance between the bearings, thereby improving the performance of the bearing function. The present invention provides a bearing support device capable of promoting the above.

[Brief description of the drawings]

FIG. 1 is a view conceptually showing a bearing support device according to the present invention.

FIG. 2 is a sectional view of a bearing support device according to an embodiment of the present invention.

FIG. 3 is a sectional view of a final reduction gear showing an application example of the bearing support device according to the present invention.

FIG. 4 is a sectional view of a conventional bearing support structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Elastic structure 12 ... Shaft 14, 16 ... Tapered roller bearing 14a, 16a ... Inner ring 14b, 16b ... Outer ring 18 ... Cylindrical spacer 20 ... Annular spacer 22 ... Nut 24 ... Mounting member 24a ... Free end 24b ... Fixed end 26 ... Base 28 ... Bolt

Claims (3)

[Claims] 1. A bearing support device for supporting a pair of bearings mounted on a shaft in a state in which a load in the axial direction is applied to the bearings, wherein an elasticity to which each fixed-side race of the pair of bearings is mounted. A bearing support device comprising a structure. 2. The elastic structure comprises an elastically deformable member having a free end and a fixed end, and a base supporting the member at the fixed end, wherein one of the members is provided at the free end of the member. The bearing support device according to claim 1, wherein the fixed-side bearing ring of a bearing is attached, and the fixed-side bearing ring of the other bearing is attached to the base. 3. The bearing support device according to claim 1, further comprising at least one spacer disposed between the respective rotating races of the pair of bearings.