JPH07243449A - Bearing device - Google Patents

Abstract

PURPOSE:To provide a bearing device which shows no contraction deformation between a rotary shaft of an oil-containing bearing and a sliding surface under the state that the oil-containing bearing is fixed to a bearing holder through press-fitting, for instance, shows satisfactory surface accuracy and concentric performance of the sliding surface, and dispenses with post-processing. CONSTITUTION:One end 11 and the other end 13 of a shaft hole of an oil- containing bearing l are reduced in their diameters than an intermediate portion 12, to serve as sliding surfaces of a rotary shaft. An outer periphery of the intermediate portion of the oil-containing bearing 1 is press-fitted and abutted to an inner port of a bearing holder 2. An outer peripheral part corresponding to the end 11 of the shaft hole of the oil-containing bearing 1 is reduced in its diameter compared to the outer peripheral parts of other portions. This small-diameter portion 14 is separated from the inner port of the bearing holder 2. A plurality of ribs 22 are formed in the inner ports of the bearing holder 2. The outer diameter portion of the oil-containing bearing 1 is press-fitted and abutted to the ribs 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device using an oil-impregnated bearing, and is applicable as a bearing device for a motor rotor, gears, and the like.

[0002]

2. Description of the Related Art Bearing devices using oil-impregnated bearings are generally
The two oil-impregnated bearings are individually press-fitted into both ends of the bearing holder, and the rotary shaft is slidably (rotatably) supported by the shaft holes of the two oil-impregnated bearings. However, when the two oil-impregnated bearings are individually press-fitted into the bearing holder, the inner diameters of both the oil-impregnated bearings are decentered due to the shrinkage of the oil-impregnated bearing inner diameter and the misalignment of the bearing housing inner diameter due to the press-fitting. Therefore, after incorporating two oil-impregnated bearings into the bearing holder, the inner diameters of the two oil-impregnated bearings are simultaneously sized or subjected to finishing processing by cutting to correct the misalignment.

Further, in order to prevent the inner diameter of the oil-impregnated bearing from being reduced when the oil-impregnated bearing is press-fitted into the bearing holder or fixed by caulking the bearing holder, the oil-impregnated bearing has a polygonal outer cross-sectional outer diameter and the oil-impregnated bearing is held in the bearing holder. Release the deformation of the bearing holder and the oil-impregnated bearing when they are fixed by press fitting or caulking into the gap created between the bearing holder and the oil-impregnated bearing,
There is also an oil-impregnated bearing which is designed to reduce the reduction deformation of the inner diameter. That is what is described in Japanese Utility Model Laid-Open No. 28322/1993.

[0004]

When two oil-impregnated bearings are individually press-fitted into the bearing holder like the conventional general bearing device using the oil-impregnated bearing, as described above, the oil-impregnated bearing is attached to the bearing holder. It is necessary to process the shaft hole of the oil-impregnated bearing again after finishing press-fitting into the bearing, but machining after the oil-impregnated bearing is incorporated into the bearing holder is difficult to obtain accuracy, and the peripheral surface of the shaft hole may be damaged. In many cases, the yield is not good, and there is a drawback that the number of processing steps is increased by one.

Further, according to the one described in the above publication, although there is an advantage that the reduction deformation of the inner diameter of the oil-impregnated bearing in the state where the oil-impregnated bearing is incorporated in the bearing holder is smaller than that of the conventional general one, press-fitting or As long as the oil-impregnated bearing is fixed to the bearing holder by caulking or the like, it cannot be said that the sliding surface of the oil-impregnated bearing with respect to the rotary shaft is reduced and deformed, and the problem that the sliding of the rotary shaft becomes unsatisfactory remains.

The present invention has been made in order to solve the above problems of the prior art. In the state where the oil-impregnated bearing is fixed to the bearing holder by press fitting or the like, the sliding surface of the oil-impregnated bearing with respect to the rotating shaft is fixed. An object of the present invention is to provide a bearing device which does not undergo contraction deformation, has good surface accuracy and concentricity of a sliding surface, and does not require post-processing.

[0007]

In order to achieve the above object, the invention according to claim 1 forms one end and the other end of a shaft hole of an oil-impregnated bearing with a diameter smaller than that of an intermediate portion. The sliding surface of the rotating shaft is characterized in that the outer circumference of the intermediate portion of the oil-impregnated bearing is press-fitted into contact with the inner hole of the bearing holder. The invention according to claim 2 is characterized in that the outer peripheral portion corresponding to one end portion of the shaft hole of the oil-impregnated bearing has a smaller diameter than the outer peripheral portions of other portions, and the small diameter portion is separated from the inner hole of the bearing holder. To do. The invention according to claim 3 is characterized in that a plurality of ribs are formed in the inner hole of the bearing holder, and the outer diameter portion of the oil-impregnated bearing is press-fitted into contact with the ribs.

[0008]

According to the first aspect of the invention, the rotary shaft is slidably supported by the small diameter portions at one end and the other end of the shaft hole of the oil-impregnated bearing. The oil-impregnated bearing has the outer periphery of the intermediate portion press-fitted into the inner hole of the bearing holder. At this time, even if the intermediate part of the oil-impregnated bearing is contracted and deformed, the intermediate part of the shaft hole of the oil-impregnated bearing is not a sliding surface with the rotating shaft, so there is no effect on the support of the rotating shaft and there is no sliding contact with the rotating shaft. Surface accuracy of one end and the other end of the shaft hole, which is the moving surface,
The concentricity is maintained at the original precision. According to the invention described in claim 2, since the outer peripheral portion of the oil-impregnated bearing corresponding to the sliding surface with respect to the rotary shaft is formed to have a small diameter and is separated from the inner hole of the bearing holder, the oil-impregnated bearing is press-fitted into the bearing holder. In this state, the sliding surface of the oil-impregnated bearing with respect to the rotary shaft does not contract and deform.
According to the third aspect of the invention, the oil-impregnated bearing and the bearing holder abut in a limited area by the plurality of ribs formed in the inner hole of the bearing holder.

[0009]

Embodiments of the bearing device according to the present invention will be described below with reference to the drawings. 1 to 3,
Reference numeral 1 indicates an oil-impregnated bearing. The oil-impregnated bearing 1 has a cylindrical outer diameter, and has a cylindrical shaft hole that rotatably supports the rotating shaft, that is, slidably in the circumferential direction. The oil-impregnated bearing 1 has the same form as two conventional oil-impregnated bearings are integrally connected. Therefore, the axial length of the oil-impregnated bearing 1 is comparable to the dimension between the two oil-impregnated bearings in the case where two oil-impregnated bearings are held by the bearing holder as in the conventional bearing device.

The shaft hole of the oil-impregnated bearing 1 includes one end portion (lower end portion in FIG. 1) 11 in the axial direction, the other end portion 13 and an intermediate portion 12 thereof.
The one end 11 and the other end 13 of the shaft hole are formed to have a smaller diameter than the intermediate part 12, and the one end 11 and the other end 13 are sliding surfaces with respect to the rotary shaft. The outer peripheral portion of the oil-impregnated bearing 1 has a portion corresponding to the one end portion 11 of the shaft hole, that is, the lower end portion in FIG. More specifically, the small-diameter portion 14 is formed over a wider range including a range corresponding to the one end 11 of the shaft hole.

The outer periphery of the intermediate portion of the oil-impregnated bearing 1 is press-fitted into and contacted with the cylindrical inner hole 21 of the bearing holder 2. The bearing holder 2 has a cylindrical portion having the inner hole 21 and a flange portion 23 protruding from the cylindrical portion in the outer peripheral direction.
And has an inwardly facing flange portion 24 at the lower end portion. Also,
A plurality of ribs 2 having a semicircular cross section are formed on the peripheral wall of the inner hole 21.
2 are formed at equal intervals in the axial direction and in the circumferential direction. Therefore, when the outer diameter portion of the oil-impregnated bearing 1 is press-fitted against the inner hole 21 of the bearing holder 2, the outer diameter portion of the oil-impregnated bearing 1 is press-fitted and brought into contact with the plurality of ribs 22. One end (lower end in FIG. 1) of the oil-impregnated bearing 1 is brought into contact with the inward flange portion 24 of the bearing holder 2.

The axial dimension of the cylindrical inner hole 21 of the bearing holder 2 is one end (lower end in FIG. 1) of the oil-impregnated bearing 1.
To the other end 13 of the shaft hole that forms a sliding surface with the rotating shaft. Therefore, in the state where the oil-impregnated bearing 2 is press-fitted into the hole 21 of the bearing holder 2 and one end of the oil-impregnated bearing 1 is in contact with the inward flange portion 24 of the bearing holder 2, the upper end of the oil-impregnated bearing 1 is pressed. The portion projects from the bearing holder 2, and the other end 13 of the shaft hole of the oil-impregnated bearing is located above the upper end of the bearing holder 2. Also,
As described above, in the outer peripheral portion of the oil-impregnated bearing 1, the portion corresponding to the one end portion 11 of the shaft hole is the small diameter portion 14 with respect to the other portions, so that the small diameter portion 14 and the inner hole of the bearing holder 2 are formed. A gap is created between the small diameter portion 14 and the inner diameter 21 of the bearing holder 2. Moreover, since the small diameter portion 14 is formed over a range wider than the range corresponding to the one end portion 11, the press-fitting range of the oil-impregnated bearing 1 into the bearing holder 2 is, as shown in FIG. It is limited within the range corresponding to the intermediate portion 12.

An example in which the bearing device described above is applied to a motor is shown in FIG. In FIG. 4, the lower end portion of the bearing holder 2 is inserted into the hole formed in the substrate 8 and
The flange portion 23 of is overlapped on the substrate 8. The center hole of the stator core 6 is fitted on the outer peripheral side of the upper end portion of the bearing holder 2, and the inner peripheral edge portion of the stator core 6 overlaps the flange portion 23. The stator core 6 and the bearing holder 2 are fixed to the substrate 8 by screwing the bolt 30 that penetrates the stator core 6 and the flange portion 23 into the substrate 8. The stator core 6 has an appropriate number of salient poles radially, and a drive coil 7 is wound around each salient pole. The oil-impregnated bearing 1 is press-fitted into the inner hole 21 of the bearing holder 2. The bearing holder 2 and the oil-impregnated bearing 1 are shown in FIG.
The same bearing device is constructed.

A rotary shaft 3 is inserted into the shaft hole of the oil-impregnated bearing 1. As described above, the shaft hole of the oil-impregnated bearing 1 is formed as a sliding surface by forming one end 11 and the other end 13 with a smaller diameter than the axial intermediate part 12, and the one end 11 and the other end 13 are formed.
The rotating shaft is in sliding contact with the sliding surface of. At the upper end of the rotary shaft 3 that slightly protrudes from the upper end of the oil-impregnated bearing 1, the bottom center of a bottomed cylindrical rotor case 4 is fixed. The peripheral wall of the rotor case 4 surrounds the stator core 6, and the inner peripheral surface of the rotor magnet 5 fixed to the inner peripheral surface of the peripheral wall of the rotor case 4 has an appropriate gap from the outer peripheral surface of each salient pole of the stator core 6. Facing each other. Therefore, as is well known, by rotating and controlling the energization of each drive coil 7 in accordance with the rotational position of the rotor magnet 5, the rotating portion including the rotary shaft 3, the rotor case 4, and the rotor magnet 5 can be rotationally driven. it can.

According to the embodiment described above, the oil-impregnated bearing 1
The one end 11 and the other end 13 of the shaft hole are formed to have a diameter smaller than the diameter of the intermediate portion 12, and this is used as the sliding surface of the rotary shaft 3, and the outer circumference of the intermediate portion of the oil-impregnated bearing 1 is set to the bearing holder 2. Since the intermediate portion 12 of the oil-impregnated bearing 1 is contracted and deformed due to the press-fitting contact, the intermediate portion 12 is not a sliding surface with the rotary shaft 3, and therefore the rotary shaft 3 is supported. The surface accuracy and concentricity of the one end 11 and the other end 13 of the shaft hole, which is the sliding surface with respect to the rotary shaft 3, are maintained at the accuracy in the initial state of the component. Therefore, it is not necessary to finish the oil-impregnated bearing 1 after incorporating it into the bearing holder 2 to obtain surface accuracy and concentricity. Also, one oil-impregnated bearing 1 is sufficient,
Since the rotary shaft 3 is rotatably supported at two positions, one end 11 and the other end 13 of the shaft hole of the oil-impregnated bearing 1, the rotary shaft 3 can be stably supported.

Further, the outer peripheral portion of the oil-impregnated bearing 1 corresponding to one end 11 forming the sliding surface of the shaft hole of the oil-impregnated bearing 1 with the rotary shaft 3 is a small diameter portion 14 from the inner hole 21 of the bearing holder 2. Since the oil-impregnated bearing 1 is pressed into contact with the bearing holder 2, the one end 11 forming the sliding surface of the oil-impregnated bearing 1 with the rotary shaft 3 does not contract and deform because the oil-impregnated bearing 1 is pressed into contact with the bearing holder 2. Also, the surface accuracy and concentricity of the sliding surface with respect to the rotating shaft 3 are maintained at the accuracy in the initial state of the parts.

Further, since a plurality of ribs 22 are formed in the inner hole 21 of the bearing holder 2 and the outer diameter portion of the oil-impregnated bearing 1 is press-contacted to the ribs 22, the oil-impregnated bearing 1 to the bearing holder 2 is formed.
Of the oil-impregnated bearing 1 escapes into the gap between the oil-impregnated bearing 1 and the bearing holder 2, and the reduction deformation of the shaft hole of the oil-impregnated bearing 1 can be eliminated. . When the bearing holder 2 is made of resin, if the plurality of ribs 22 are not provided, the bearing holder is easily cracked when the oil-impregnated bearing 1 is press-fitted and brought into contact with the inner hole 21 of the bearing holder 2, but as described above, According to the structure in which the outer diameter portion of the oil-impregnated bearing 1 is press-fitted against a plurality of ribs 22 formed in the inner hole 21 of the second oil-impregnated bearing 1, the deformation of the oil-impregnated bearing 1 caused by the press-fitting abutment causes the oil-impregnated bearing 1 and the bearing holder. Even if the bearing holder 2 is made of resin, it does not crack because it escapes into the gap between the bearing holder 2 and the bearing holder 2.

In the illustrated embodiment, only the outer peripheral portion corresponding to one end portion of the shaft hole of the oil-impregnated bearing 1 has a smaller diameter than the outer peripheral portions of the other portions, but it corresponds to the other end portion of the shaft hole. The outer peripheral portion may also have a small diameter. The bearing device according to the present invention is
The present invention can be applied not only to a bearing device for a motor but also as a bearing device for a gear and a bearing device for various rotating bodies.

[0019]

According to the first aspect of the invention, the diameter of one end and the other end of the shaft hole of the oil-impregnated bearing is formed to be smaller than the diameter of the intermediate part, and this is a sliding surface with the rotary shaft. Since the outer periphery of the oil-impregnated bearing is pressed into contact with the inner hole of the bearing holder, even if the intermediate part of the oil-impregnated bearing contracts due to press-fit contact, this intermediate part is not a sliding surface with the rotating shaft. Therefore, there is no effect on the support of the rotary shaft, and the surface accuracy and concentricity of the one end and the other end of the shaft hole, which is the sliding surface with the rotary shaft, are maintained at the accuracy of the original parts. Be drunk Therefore, it is not necessary to finish the oil-impregnated bearing into the bearing holder to obtain surface accuracy and concentricity.

According to the second aspect of the invention, the outer diameter of the oil-impregnated bearing, which corresponds to one end forming a sliding surface of the shaft hole of the oil-impregnated bearing with respect to the rotary shaft, has a small diameter from the inner hole of the bearing holder. Since they are separated from each other, the one end that forms the sliding surface with the rotating shaft of the oil-impregnated bearing does not shrink and deform in the state where the oil-impregnated bearing is press-fitted into contact with the bearing holder. There is an advantage that the surface accuracy and concentricity of the sliding surface can be maintained to the accuracy in the initial state of the parts.

According to the third aspect of the present invention, a plurality of ribs are formed in the inner hole of the bearing holder, and the outer diameter portion of the oil-impregnated bearing is press-fitted against the ribs, so that the oil-impregnated bearing is press-fitted into the bearing holder. The contact is easy, and the deformation of the oil-impregnated bearing due to the press-fit contact is released into the gap between the oil-impregnated bearing and the bearing holder, so that the contraction deformation of the shaft hole of the oil-impregnated bearing can be eliminated.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a bearing device according to the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a vertical cross-sectional view of the oil-impregnated bearing in the above embodiment.

FIG. 4 is a vertical cross-sectional view showing an example of a motor using the oil-impregnated bearing according to the above embodiment.

[Explanation of symbols]

 1 Oil-impregnated bearing 2 Bearing holder 3 Rotating shaft 11 One end of shaft hole 12 Intermediate part of shaft hole 13 Other end of shaft hole 14 Small diameter part 22 Rib

Claims (3)

[Claims] 1. A bearing device comprising a cylindrical oil-impregnated bearing in which a shaft hole for slidably supporting a rotary shaft is formed, and a bearing holder in which the oil-impregnated bearing is press-fitted into an inner hole. In the oil-impregnated bearing, one end portion and the other end portion of the shaft hole are formed to have a smaller diameter than the intermediate portion to form a sliding surface of the rotary shaft, and the outer periphery of the intermediate portion of the oil-impregnated bearing is inside the bearing holder. A bearing device characterized by being press-fitted into contact with a hole. 2. The oil-impregnated bearing has an outer peripheral portion corresponding to one end of the shaft hole having a smaller diameter than outer peripheral portions of other portions,
The bearing device according to claim 1, wherein the small diameter portion is separated from the inner hole of the bearing holder. 3. The bearing device according to claim 1, wherein a plurality of ribs are formed in the inner hole of the bearing holder, and the outer diameter portion of the oil-impregnated bearing is press-fitted into contact with the ribs.