JP2006038081A - Oil-impregnated metal bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To install a rotary shaft onto a bearing housing without inclination even when the axis of sliding surfaces of oil-impregnated metal bearings fitted into the bearing housing at an upper and a lower position is inclined to the axis of the bearing housing. <P>SOLUTION: The oil-impregnated metal bearings 1 and 1 are fitted into the bearing housing 5 at two positions in the axial direction. In the oil-impregnated metal bearings 1 and 1, an outer circumferential surface forms a fit-in surface 21, and an inner circumferential surface is formed as the sliding surface 22 to the rotary shaft partly in the axial direction, while the other part in the axial direction is formed as a non-sliding surface 23. The oil-impregnated metal bearing 1 comprises a bearing main part 3 on one end side in the axial direction, and a bearing auxiliary part 4 on the other end side in the axial direction. The fit-in surface 21 and the sliding surface 22 are thus formed of the outer circumferential surface and the inner circumferential surface of the bearing main part 3. Height of the fit-in surface 21 at an axial direction center position 1 is thus set to coincide with height of the sliding surface 22 at an axially center position b. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an oil-impregnated metal bearing device, and more particularly, to an oil-impregnated metal bearing device configured by press-fitting a cylindrical oil-impregnated metal bearing into two axial positions of a cylindrical bearing housing.

  FIG. 4 is a longitudinal sectional view illustratively showing the problems of this type of conventional oil-impregnated metal bearing device A, and FIG. 5 is a longitudinal sectional view of the oil-impregnated metal bearing 1 used in the oil-impregnated metal bearing device A. .

  As shown in FIG. 5, the oil-impregnated metal bearing 1 is manufactured in a cylindrical shape using a copper alloy or the like, and the entire outer peripheral surface thereof is formed as a press-fit surface 21, whereas the inner peripheral surface is in the axial direction. Is formed as a sliding surface 22 with respect to a rotating shaft (not shown, the same applies hereinafter), and the remaining portion in the axial direction is formed as a non-sliding surface 23 having a diameter larger than that of the sliding surface 22. .

  In this oil-impregnated metal bearing 1, only a part of the inner circumferential surface in the axial direction is formed as a sliding surface 22 and the remaining portion is formed as a non-sliding surface 23, so that the volume of the oil-impregnated metal bearing 1 is ensured to be large. In addition to improving the service life by sufficiently securing the oil content, and making the entire shaft length of the oil-impregnated metal bearing 1 longer to facilitate the press-fitting process into the bearing housing 5 shown in FIG. By reducing the area of the sliding surface 22 as much as possible, the viscous resistance of the oil interposed between the rotating shaft and the sliding surface 22 is reduced and reduced.

  In the oil-impregnated metal bearing 1 having this configuration, the entire outer peripheral surface is the press-fitting surface 21, and the sliding surface 22 is formed only on one end side of the inner peripheral surface. The height position inevitably differs from the center position a in the direction and the center position b in the axial direction of the sliding surface 22, which is also indicated by a chain line.

  On the other hand, in the oil-impregnated metal bearing device A configured by press-fitting the oil-impregnated metal bearings 1 and 1 having the configuration described in FIG. 5 into the upper and lower portions of the cylindrical bearing housing 5 shown in FIG. In the press-fitting process of the bearing 1, the end 21 a of the press-fitting surface 21 of the oil-impregnated metal bearing 1 is pressed into two places by a phenomenon called “galling” that occurs when the end 21 a of the oil-impregnated metal bearing 1 is caught on the inner peripheral surface 51 of the bearing housing 5. Although the situation where one or both of the oil-impregnated metal bearings 1 is still attached to the bearing housing 5 in a state of being inclined by a minute angle can occur, each oil-impregnated metal is acceptable if the inclination angle is within an allowable range. In many cases, the rotary shafts (not shown) are rotatably supported by the sliding surfaces 22 and 22 of the bearings 1 and 1 for actual use.

As another conventional example, when a metal bearing of a motor is press-fitted into a bearing holding portion, there is a technique in which gaps that are useful for suppressing deformation of the inner peripheral surface of the metal bearing are formed at a plurality of locations of the metal bearing. It is known (see Patent Document 1). Further, by taking a measure of press-fitting the fixed portion of the bearing member having the fixed portion press-fitted into the bearing holder and the bearing portion having an inherent bearing function at different locations in the axial direction into the bearing holder. There is also known a bearing device in which the influence of press-fitting stress is hardly exerted on the bearing portion (see Patent Document 2). Furthermore, a self-aligning bearing is known in which a bearing is provided with a self-aligning function by fitting protrusions provided at a plurality of locations on the outer periphery of one end of the bearing into a socket (see Patent Document 3).
JP 2003-47193 A JP 2001-248644 A Japanese Patent Laid-Open No. 3-48012

  However, the following problems were found in the oil-impregnated metal bearing device illustrated in FIG. That is, assuming that both of the two oil-impregnated metal bearings 1 and 1 press-fitted in two upper and lower portions of the bearing housing 5 are inclined in the same direction by a minute angle within an allowable range, In this case, the axis 24 of the sliding surface 22 of the upper oil-impregnated metal bearing 1 and the axis 24 of the sliding surface 22 of the lower oil-impregnated metal bearing 1 are both θ1 and θ2 with respect to the axis L of the bearing housing 5. The center Q of the axial center position b of each sliding surface 22 is displaced with respect to the axis L of the bearing housing 5 as it is inclined by the indicated angle. Therefore, the axis (rotation axis) R of the rotation shaft (not shown) rotatably supported by the sliding surfaces 22 and 22 of the two upper and lower oil-impregnated metal bearings 1 and 1 is the center Q, Q, respectively. In accordance with the deviation width of the bearing housing 5 from the axis L, there occurs a situation where the bearing housing 5 is inclined by an angle indicated by the symbol θ. The same situation occurs when only one of the two oil-impregnated metal bearings 1 and 1 press-fitted into the upper and lower portions of the bearing housing 5 is tilted by a minute angle within the allowable range, or when these oil-impregnated metal bearings 1 and 1 are inclined. In addition to the case where both of them are inclined in different directions, this may occur when the two oil-impregnated metal bearings 1, 1 are press-fitted into the bearing housing 5 with their upper and lower sides directed in the same direction.

  By the way, in a magnetic tape device such as a magnetic recording / reproducing apparatus that performs recording / reproduction by rotating a rotating magnetic head built in the drum while winding the magnetic tape around the drum, A rotating drum on the side of the rotating drum portion to which the rotating magnetic head is attached is rotatably supported via an oil-impregnated metal bearing in a fixed drum portion and a bearing housing integrated with the fixed drum portion. In this case, if the rotating shaft on the rotating drum portion side is attached to be inclined with respect to the bearing housing, between the traveling path of the magnetic tape regulated by the fixed drum and the rotating path of the rotating magnetic head. There is a risk that the position accuracy of the recording head may be lowered, and the service life of the rotating magnetic head or the magnetic tape may be impaired, or the read / write performance of recorded information may be deteriorated.

  In view of the above situation, the techniques proposed in the above-mentioned Patent Document 1 and Patent Document 2 are intended to suppress the deformation of the sliding surface due to the influence of press-fitting, so that the above problems are solved. It cannot be a solution. In addition, the technique described in Patent Document 3 merely aims to achieve self-alignment through displacement of a press-fitted bearing.

  The present invention has been made under the above circumstances, and the axis of one or both sliding surfaces of the oil-impregnated metal bearing press-fitted into two upper and lower portions of the bearing housing due to a galling phenomenon at the time of press-fitting is the axis of the bearing housing. The center of the axial center position of the sliding surface of each of the two oil-impregnated metal bearings at the upper and lower positions does not shift with respect to the axis of the bearing housing. By taking such measures, an oil-impregnated metal bearing device that does not cause a situation in which a rotating shaft that is rotatably supported via an oil-impregnated metal bearing press-fitted into the bearing housing does not occur is provided for the bearing housing. For the purpose.

  In the oil-impregnated metal bearing device according to the present invention, cylindrical oil-impregnated metal bearings are press-fitted into two axial directions of a cylindrical bearing housing, and the outer peripheral surface of these oil-impregnated metal bearings forms a press-fit surface. A part of the circumferential surface is formed as a sliding surface with respect to the rotating shaft, and the remaining portion in the axial direction is formed as a non-sliding surface having a diameter larger than that of the sliding surface. Therefore, this oil-impregnated metal bearing increases the service life of the oil-impregnated metal bearing by increasing the volume of the oil-impregnated metal bearing and ensuring sufficient oil content. Easy measures such as making the press-fitting work easy, reducing the area of the sliding surface as much as possible and reducing the viscous resistance of the oil interposed between the rotating shaft and the sliding surface, and reducing it. It can be planned.

  And in this invention, the height of the axial direction center position of the said press-fit surface of an oil-impregnated metal bearing is made to correspond with the height of the axial direction center position of the said sliding surface.

  In the oil-impregnated metal bearing device employing this configuration, the center of the axial center position of the sliding surface of the oil-impregnated metal bearing coincides with the center of the axial center position of the press-fit surface. Therefore, even if the above-mentioned galling phenomenon occurs when the oil-impregnated metal bearing is press-fitted into the bearing housing, the center of the axial center position of the sliding surface is centered even if the axis of the sliding surface is inclined with respect to the axis of the bearing housing. The situation that the position shifts with respect to the axis of the bearing housing does not occur. Therefore, a situation in which the axis of the rotary shaft rotatably supported via the oil-impregnated metal bearing press-fitted into the bearing housing is not inclined with respect to the axis of the bearing housing.

  In the present invention, the axial length of the press-fitting surface of the oil-impregnated metal bearing may be different from the axial length of the press-fitting surface of the oil-impregnated metal bearing. It is preferable to adopt a configuration in which the length is the same as the axial length of the surface, and by doing so, the manufacture of the oil-impregnated metal bearing is facilitated.

  The oil-impregnated metal bearing is divided into a bearing main portion and a bearing auxiliary portion in the axial direction, and the press-fitting surface and the sliding surface are formed by the outer peripheral surface and the inner peripheral surface of the bearing main portion, respectively. In addition, it is desirable to adopt a configuration in which the outer peripheral surface of the bearing auxiliary portion is formed to be smaller in diameter than the press-fitting surface, which makes it easier to manufacture the oil-impregnated metal bearing. .

  In the oil-impregnated metal bearing device according to the present invention, cylindrical oil-impregnated metal bearings are press-fitted into two axial directions of a cylindrical bearing housing, and the outer peripheral surface of these oil-impregnated metal bearings forms a press-fit surface. An oil-impregnated metal bearing device in which a part of the circumferential direction is formed as a sliding surface with respect to the rotating shaft and a remaining portion in the axial direction is formed as a non-sliding surface having a diameter larger than that of the sliding surface. The oil-impregnated metal bearing is axially partitioned into a bearing main portion at one axial end side and a bearing auxiliary portion at the other axial end side, and the press-fitting surface and the sliding surface are connected to the bearing main portion. By forming each of the outer peripheral surface and the inner peripheral surface to have the same axial length, the height of the axial center position of the press-fit surface is set to the height of the axial center position of the sliding surface. The bearing auxiliary part is connected to one side of the bearing main part. The outer peripheral surface protrudes to be smaller in diameter than the press-fit surface, and the base of the outer peripheral surface of the bearing auxiliary portion is formed as a continuous tapered surface without forming a step on the press-fit surface. , It is made more concrete by adopting the configuration.

  In this case, the oil-impregnated metal bearing has a bearing main portion having a press-fit surface and a sliding surface having the same axial length on one end side in the axial direction, and the bearing auxiliary portion having the above-described configuration on the other end side in the axial direction. Since the base portion of the outer peripheral surface of the bearing auxiliary portion is formed as a continuous tapered surface without forming a step on the press-fit surface, it is possible to easily perform the press-fit process on the bearing housing, There is an advantage that the above-described galling phenomenon is less likely to occur during press-fitting. Other operations and the like will be described in detail with reference to embodiments described later.

  As described above, according to the present invention, it is assumed that the axis of one or both sliding surfaces of the oil-impregnated metal bearing press-fitted into the upper and lower portions of the bearing housing remains inclined with respect to the axis of the bearing housing. However, the centers of the axial center positions of the sliding surfaces of the two oil-impregnated metal bearings at the upper and lower positions are not displaced relative to the axis of the bearing housing. Therefore, a situation in which the axis of the rotary shaft that is rotatably supported via the oil-impregnated metal bearing press-fitted into the bearing housing is not inclined with respect to the bearing housing. Therefore, the oil-impregnated metal bearing device according to the present invention can be suitably used as an oil-impregnated metal bearing device that is employed when the rotating drum portion is rotatably attached to the fixed drum portion in the drum of the magnetic tape device. By doing so, it is possible to improve the durability performance of the rotating magnetic head and magnetic tape of the magnetic tape device.

  FIG. 1 is a longitudinal sectional view illustratively showing an oil-impregnated metal bearing device A according to the present invention, and FIG. 2 is a longitudinal sectional view of an oil-impregnated metal bearing 1 used in the oil-impregnated metal bearing device A.

  The cylindrical oil-impregnated metal bearing 1 shown in FIG. 2 is partitioned in the axial direction into a bearing main portion 3 on one axial end side and a bearing auxiliary portion 4 on the other axial end side. And the outer peripheral surface of the bearing main part 3 is formed as the press-fit surface 21, the inner peripheral surface is formed as the sliding surface 22, and the axial length H of these surfaces 21 and 22 is set to the same length. is there. By adopting this configuration, the height of the axial center position a of the press-fitting surface 21 indicated by the alternate long and short dash line is made to coincide with the height of the axial center position b of the sliding surface 22. Further, the bearing auxiliary portion 4 has an outer peripheral surface 41 having a smaller diameter than the press-fit surface 21, and an inner peripheral surface formed as a non-sliding surface 23 having a larger diameter than the sliding surface 22.

  In the oil-impregnated metal bearing device A configured by press-fitting the oil-impregnated metal bearing 1 having the configuration described with reference to FIG. 2 into the upper and lower portions of the cylindrical bearing housing 5 shown in FIG. 1, two oil-impregnated metals are provided. In each of the bearings 1 and 1, the center P of the axial center position a of the press-fit surface 21 and the center Q of the axial center position b of the sliding surface 22 coincide with each other. Therefore, when the oil-impregnated metal bearing 1 is press-fitted into the bearing housing, the galling phenomenon described at the beginning occurs, and the axis 24 of the sliding surface 22 of the oil-impregnated metal bearing 1 is inclined with respect to the axis L of the bearing housing 5. In addition, the center Q of the axial center position b of the sliding surface 22 is positioned on the axis L of the bearing housing 5, so that a situation in which they are not displaced does not occur. Therefore, the axis R of the rotary shaft that is rotatably supported by the bearing housing 5 via the oil-impregnated metal bearings 1 and 1 press-fitted into the bearing housing 5 coincides with the axis L of the bearing housing 5. The situation where the axis R of the rotary shaft is inclined with respect to the axis L of the bearing housing 5 does not occur. Therefore, if the rotating drum portion is attached to the fixed drum portion of the drum of the magnetic tape device via the oil-impregnated metal bearing device A described in FIG. 1, the traveling path of the magnetic tape and the rotating magnetic head on the rotating drum portion side Thus, the positional accuracy between the rotating head and the rotating path is improved, the service life of the rotating magnetic head and the magnetic tape is improved, and the read / write performance of the recorded information is also improved.

  FIG. 3 is a longitudinal sectional view showing an oil-impregnated metal bearing 1 and a part of the bearing housing 5 according to a modification. The oil-impregnated metal bearing 1 shown in FIG. 1 is divided into a bearing main portion 3 and a bearing auxiliary portion 4 in the axial direction, and a press-fitting surface 21 and a sliding surface 22 are formed on an outer peripheral surface and an inner peripheral surface of the bearing main portion 3. The bearing auxiliary portion 4 has an outer peripheral surface 41 that is smaller in diameter than the press-fitting surface 21. The base portion of the outer peripheral surface 41 of the bearing auxiliary portion 4 is formed as a continuous tapered surface 42 without forming a step on the press-fit surface 21. In the figure, D1 indicates the diameter of the press-fitting surface, D2 indicates the diameter of the outer peripheral surface 41 of the bearing auxiliary portion 4, and D3 indicates the diameter of the inner peripheral surface 51 of the bearing housing 5. As can be seen from FIG. The diameter D1 of the press-fit surface is larger than the diameter D3 of the inner peripheral surface 51 of the bearing housing 5, and the diameter D2 of the outer peripheral surface 41 of the bearing auxiliary portion 4 is smaller than that.

  In the step of press-fitting the oil-impregnated metal bearing 1 described in FIG. 3 into the bearing housing 5, the lower end portion of the bearing auxiliary portion 4 can be easily loosely fitted to the bearing housing 5 at the initial stage of the step. The initial insertion of the bearing 1 into the bearing housing 5 can be easily performed, and in the press-fitting stage, the tapered surface 42 functions as a guide surface and the press-fitting surface 21 is introduced into the bearing housing 5. Therefore, the press-fitting surface 21 is smoothly press-fitted into the bearing housing 5. Therefore, there is an advantage that a galling phenomenon in the press-fitting process is less likely to occur.

  1 to 5, the same or corresponding parts are denoted by the same reference numerals.

1 is a longitudinal sectional view illustratively showing an oil-impregnated metal bearing device according to the present invention. It is a longitudinal cross-sectional view of the oil-impregnated metal bearing used for the oil-impregnated metal bearing device. It is the longitudinal cross-sectional view which showed the oil-impregnated metal bearing by a modification, and a part of bearing housing. It is the longitudinal cross-sectional view which showed the problem of the conventional oil-impregnated metal bearing apparatus explanatory. It is a longitudinal cross-sectional view of the oil-impregnated metal bearing used for the oil-impregnated metal bearing device of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Oil-impregnated metal bearing 3 Bearing main part 4 Bearing auxiliary part 5 Bearing housing 21 Press-fit surface 22 Sliding surface 23 Non-sliding surface 41 Outer peripheral surface of bearing auxiliary part 42 Taper surface H Shaft length of the press-fitting surface or sliding surface a Press-fitting surface The axial center position of the b b The axial center position of the sliding surface

Claims (4)

Cylindrical oil-impregnated metal bearings are press-fitted at two locations in the axial direction of the cylindrical bearing housing. These oil-impregnated metal bearings have a press-fit surface on the outer peripheral surface, and a part of the inner peripheral surface in the axial direction. In the oil-impregnated metal bearing device which is formed as a sliding surface with respect to the rotating shaft and the remaining portion in the axial direction is formed as a non-sliding surface having a diameter larger than that of the sliding surface,
An oil-impregnated metal bearing is partitioned in the axial direction into a bearing main portion on one axial end side and a bearing auxiliary portion on the other axial end side, and the press-fitting surface and the sliding surface are arranged on the outer peripheral surface of the bearing main portion. And the inner peripheral surface, and the axial lengths of the respective surfaces are made the same, so that the height of the axial center position of the press-fitting surface is set to the height of the axial center position of the sliding surface. The bearing auxiliary portion extends to one side of the bearing main portion, and its outer peripheral surface is formed smaller in diameter than the press-fit surface, and the base portion of the outer peripheral surface of the bearing auxiliary portion is An oil-impregnated metal bearing device, wherein the press-fitted surface is formed as a continuous tapered surface without forming a step. Cylindrical oil-impregnated metal bearings are press-fitted at two locations in the axial direction of the cylindrical bearing housing. These oil-impregnated metal bearings have a press-fit surface on the outer peripheral surface, and a part of the inner peripheral surface in the axial direction. In the oil-impregnated metal bearing device which is formed as a sliding surface with respect to the rotating shaft and the remaining portion in the axial direction is formed as a non-sliding surface having a diameter larger than that of the sliding surface,
An oil-impregnated metal bearing device, wherein the height of the axial center position of the press-fitting surface of the oil-impregnated metal bearing is made to coincide with the height of the axial center position of the sliding surface. The oil-impregnated metal bearing device according to claim 2, wherein the axial length of the press-fitting surface of the oil-impregnated metal bearing is the same as the axial length of the sliding surface. An oil-impregnated metal bearing is divided into a bearing main portion and a bearing auxiliary portion in the axial direction, and the press-fitting surface and the sliding surface are formed by an outer peripheral surface and an inner peripheral surface of the bearing main portion, respectively. The oil-impregnated metal bearing device according to claim 3, wherein an outer peripheral surface of the bearing auxiliary portion is formed smaller in diameter than the press-fitting surface.

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