JPH04300414A - Bearing device - Google Patents

Abstract

PURPOSE:To provide a bearing device which is equipped with a connection groove that prevents a fluid from flowing out to the outside. CONSTITUTION:A thrust receiving member 2 is put on one end portion of a housing 1 inner periphery surface, and a housing 1 inner periphery surface as a radial bearing surface 4 faces the outer periphery surface radial receiving surface 5 of a shaft body 3 provided at the housing 1 inner periphery, and a radial bearing R is constituted, and a thrust bearing surface 6 provided at the member 2 and a thrust receiving surface 7 provided at the end surface of the shaft body 3 face to each other, and a thrust bearing S is constituted. A connection groove 26 which passes through fluids on both sides of the contact portion 23 of the member 2 and the housing 1, is provided at the housing 1 inner periphery surface, and a shaft body side portion 24 is made deeper than a shaft body opposite side 25 in its groove depth. When the housing 1 is rotated, fluid flow in the groove 26 runs toward the bearing inside, and flowing out to the outside is restrained.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] This invention relates to bearing devices used in video equipment, audio equipment, office equipment, etc. such as VTRs (video tape recorders), DATs (digital audio tape recorders), and HDDs (hard disk drive spindles). .

0002

2. Description of the Related Art Conventionally, as shown in FIG. 7, a thrust receiving member 2 is fitted and attached to one end of the inner circumferential surface of a housing 1, and a shaft body 3 is disposed on the inner circumference of the housing 1. established,
A radial bearing surface 4 provided on the inner peripheral surface of the housing 1 faces a radial bearing surface 5 provided on the outer peripheral surface of the shaft body 3, thereby forming a radial bearing R. Further, the thrust receiving member 2
A thrust bearing surface 6 provided on the shaft body 1 and a thrust bearing surface 7 provided on the end surface of the shaft body 1 face each other to form a thrust bearing S. A thrust receiving member 2 is provided on the inner peripheral surface of the housing 1.
A communication groove 8 for communicating fluid on both sides of the contact portion between the housing 1 and the housing 1 is provided in the axial direction of the housing and has a constant depth.

0003

[Problem to be Solved by the Invention] The shaft body 3 is connected to the housing 1.
When the shaft body 3 is inserted into the inner peripheral surface of the housing 1, the fluid between the shaft body 3 and the thrust receiving member 2 flows out from the communication groove 8 to the outside of the housing 1, so that the shaft body 3 can be smoothly inserted into the inner peripheral surface of the housing 1. can be inserted.

However, since the communication groove 8 is provided with a certain depth in the axial direction of the shaft body 3, when the housing 1 rotates with respect to the shaft body 3 together with the thrust receiving member 2, the thrust There is a problem in that centrifugal force is generated in the fluid that lubricates the bearing S, and a portion of the fluid flows out through the communication groove 8.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and it is an object of the present invention to provide a bearing device having a communication groove that prevents fluid from flowing out.

[0006]

[Means for Solving the Problems] According to the present invention, a thrust receiving member is fitted and attached to one end of the inner circumferential surface of the housing, and a shaft body is disposed on the inner circumference of the housing. A radial bearing surface provided on the inner circumferential surface of the shaft faces a radial bearing surface provided on the outer circumferential surface of the shaft body to form a radial bearing, and a thrust bearing surface provided on the thrust receiving member and a radial bearing surface provided on the end surface of the shaft body A bearing device in which the thrust bearing surface faces each other to form a thrust bearing, and a communication groove is provided on the inner circumferential surface of the housing to communicate fluid on both sides of a contact portion between the thrust receiving member and the housing, The communication groove was made deeper on the side of the shaft than on the opposite side of the shaft.

Furthermore, the communication groove may be inclined in the direction of rotation of the housing relative to the shaft body from a side portion of the shaft body toward an opposite side portion of the shaft body.

[0008]

[Operation] When inserting the shaft into the inner peripheral surface of the housing,
The fluid between the shaft body and the thrust receiving member flows out of the housing from the communication groove, and the shaft body is smoothly inserted into the inner peripheral surface of the housing. When the housing rotates with respect to the shaft, the flow of fluid in the communication groove is guided by the slope of the groove toward the inside of the bearing, which is the shaft, and is prevented from flowing outside.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the same reference numerals are given to parts that are the same as or corresponding to the conventional ones. FIG. 1 is a longitudinal sectional view of a first embodiment in which the bearing device of the present invention is used in a rotating cylinder for a magnetic head.
FIG. 2 is an enlarged view of the main parts of the bearing device. A steel ball for a ball bearing is press-fitted and attached as a thrust receiving member 2 to one end (the upper end in the figure) of the inner peripheral surface of the cylindrical housing 1. The lower surface of this thrust receiving member 2 serves as a thrust bearing surface 6 having a convex spherical surface. A shaft body 3 is disposed on the inner periphery of the housing 1, and a flat thrust receiving surface 7 is provided on the upper end surface of the shaft body 3. This thrust bearing surface 7 opposes the thrust bearing surface 6 and constitutes a thrust bearing S. Further, on the outer peripheral surface of the shaft body 3, cylindrical radial bearing surfaces 5 are provided at two locations at intervals in the axial direction, and these radial bearing surfaces 5 are provided with herringbone-shaped grooves for generating dynamic pressure. 20 are provided respectively. On the other hand, a shaft body 3 is provided on the inner peripheral surface of the housing 1.
A cylindrical radial bearing surface 4 is provided opposite to the radial bearing surface 5, and this radial bearing surface 4 and the radial bearing surface 5 constitute a radial bearing R. Further, an inner circumferential groove 21 is provided on the inner circumferential surface of the housing 1 at a location between the upper and lower radial bearing surfaces 4, and an air vent hole 22 penetrating from the inner circumferential groove 21 to the outer circumferential surface of the housing 1 is provided in the housing 1. It is provided on the body of 1.

At the upper end of the inner peripheral surface of the housing 1, both sides of the contact portion 23 between the thrust receiving member 2 and the housing 1,
That is, one communication groove 26 that communicates between the shaft body side portion 24 that communicates with the inside of the bearing and the opposite side portion 25 that communicates with the outside of the bearing.
Although provided in the axial direction, the bottom surface 26a of the communication groove 26 in this embodiment is an inclined surface, and the depth of the shaft body side portion 24 is deeper than the opposite side portion 25.

The shaft body 3 of the bearing device constructed as described above is erected with its lower end portion press-fitted into the lower cylinder 30. On the other hand, the upper end of the housing 1 is connected to the upper cylinder 3.
It is fixed at 1. A rotor magnet 32 of a rotary drive motor is rotatably attached to the lower surface of the upper cylinder 31. The stator coil 33 of the rotary drive motor is attached to the inner circumferential surface of the side wall of the lower cylinder 30 so as to face the rotor magnet 32 on its circumferential surface. Further, a cylindrical fixed-side rotary transformer 34 is attached to the lower cylinder 30 so as to surround the outer periphery of the housing 1, and a rotating-side rotary transformer 35 having an inner circumferential surface facing the outer circumferential surface of the fixed-side rotary transformer 34, It is attached to the lower surface of the upper cylinder 31, and the signal from the magnetic head 36 provided on the upper cylinder 31 is transmitted to the stationary rotary transformer 34 via the rotating rotary transformer 35, and is amplified and extracted.

Next, the operation will be explained. When the shaft body 3 is inserted into the inner peripheral surface of the housing 1, the fluid between the shaft body 3 and the thrust receiving member 2 flows out of the housing 1 through the communication groove 26, and the shaft body 3 is inserted into the inner peripheral surface of the housing 1. It is inserted smoothly into the surface.

When the stator coil 33 of the rotary drive motor is energized, a rotational force is generated in the rotor magnet 32, and the housing 1 and the accessories fixed thereto rotate integrally. At this time, in the thrust bearing S, the housing 1 is supported in the axial direction and rotates with the thrust bearing surface 6 in point contact with the thrust bearing surface 7. Furthermore, due to the pumping action of the grooves 20 and 20 for generating dynamic pressure in the shaft body 3, the pressure of the fluid in the radial bearing clearance between the radial bearing surface 4 and the radial bearing surface 5 increases, and the housing 1 It is supported in the radial direction and rotates without contacting the body 3.

When the housing 1 rotates together with the thrust bearing member 2 in this manner, the fluid in the thrust bearing S is
As shown by the arrow marks in FIG. 2, it flows upward along the spherical surface of the thrust receiving member 2. However, when it reaches the inclined groove bottom surface 26a of the communication groove 26, it changes direction, and is guided by the slope of the groove bottom surface 26a, so that the groove depth becomes deeper and the resistance decreases.
Head to the bottom of 4. In this way, fluid is prevented from flowing out of the housing 1.

FIG. 3 is a plan view of a bearing device showing a second embodiment. In this case, a plurality of communication grooves 26 (three in the figure) are provided, and the minimum passing area of each communication groove 26 is It is smaller than that of the first embodiment. This embodiment has the advantage that it is easier to prevent the fluid from flowing out.

FIG. 4 is a vertical cross-sectional view of a main part of a bearing device showing a third embodiment, in which the thrust bearing surface 6 at the upper end of the shaft body 3 is a concave spherical surface matching the spherical surface of the thrust receiving member 2, and the thrust bearing At least one of the surface 6 and the thrust receiving surface 7,
This embodiment differs from the above-mentioned embodiments in that a spiral dynamic pressure generating groove 27 that sucks fluid inward during rotation is formed. The functions and effects of the communication groove 26 are the same as in each of the above embodiments.

FIG. 5 shows a fourth embodiment. The communication groove 26A of this embodiment is formed as a spiral groove on the inner peripheral surface of the housing 1, and is inclined in the rotational direction Y of the housing 1 from the shaft body side part 24 toward the opposite side part 25 of the shaft body. . When the housing 1 rotates in the direction of arrow Y, fluid flows from the opposite side 25 of the shaft toward the side 24 of the shaft, and outflow of the fluid to the outside of the housing 1 is inhibited.

FIG. 6 shows a fifth embodiment in which the communication groove 26B is formed in a spiral shape as in the fourth embodiment, and the depth of the groove is varied from the opposite side 25 of the shaft to the side of the shaft. It gradually deepens towards 24. Since the slope of the groove becomes larger as the groove depth becomes deeper, there is an advantage that the outflow of fluid to the outside of the housing 1 can be more easily suppressed than in the case of the fourth embodiment.

In each of the above embodiments, a steel ball is used as the thrust receiving member 2, but a cylindrical roller may be fitted and attached instead. In that case, the thrust bearing surface 7 on the upper end surface of the shaft body 3 may be made into a convex spherical shape, and the thrust bearing surface 6 of the cylindrical roller may be made into a planar shape. Further, both the thrust bearing surface 7 on the upper end surface of the shaft body 3 and the thrust bearing surface 6 of the cylindrical roller may be made flat, and a groove for generating dynamic pressure may be provided in at least one of them.

[0020]

According to the first aspect of the invention, the depth of the communication groove provided on the inner peripheral surface of the housing is made deeper on the side of the shaft than on the opposite side of the shaft. Further, in the invention according to claim 2, the communication groove is inclined in the direction of rotation of the housing with respect to the shaft body from the side portion of the shaft body toward the opposite side portion of the shaft body. Therefore, when the housing rotates with respect to the shaft, the flow of fluid is guided by the slope of the communication groove toward the inside of the bearing, which is the shaft, and has the effect of preventing outflow to the outside.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a first embodiment in which a bearing device of the present invention is used in a rotating cylinder for a magnetic head.

FIG. 2 is a longitudinal sectional view showing an enlarged main part of the bearing device in FIG. 1;

FIG. 3 is a plan view of the second embodiment.

FIG. 4 is a vertical sectional view of a main part of a third embodiment.

FIG. 5 is a vertical sectional view of a main part of a fourth embodiment.

FIG. 6 is a vertical sectional view of a main part of a fifth embodiment.

FIG. 7 is a vertical sectional view of a main part of a conventional bearing device.

[Explanation of symbols]

1 Housing 2 Thrust receiving member 3 Shaft body 4 Radial bearing surface 5 Radial bearing surface 6 Thrust bearing surface 7 Thrust bearing surface 26 Communication groove 26A Communication groove 26B Communication groove

Claims (2)

[Claims] 1. A radial bearing provided on the inner circumferential surface of the housing, wherein a thrust receiving member is fitted and attached to one end of the inner circumferential surface of the housing, a shaft body is disposed on the inner circumferential surface of the housing, and The surface faces the radial bearing surface provided on the outer peripheral surface of the shaft body to form a radial bearing, and the thrust bearing surface provided on the thrust receiving member and the thrust bearing surface provided on the end surface of the shaft body face each other to form a thrust bearing surface. In a bearing device that constitutes a bearing and is provided with a communication groove on the inner circumferential surface of the housing that communicates fluid on both sides of a contact portion between the thrust receiving member and the housing, the communication groove has a side portion of the shaft body on the opposite side of the shaft body. A bearing device characterized by having a depth greater than the depth of the part. 2. A radial bearing provided on the inner circumferential surface of the housing, wherein a thrust receiving member is fitted and attached to one end of the inner circumferential surface of the housing, a shaft body is disposed on the inner circumferential surface of the housing, and The surface faces the radial bearing surface provided on the outer peripheral surface of the shaft body to form a radial bearing, and the thrust bearing surface provided on the thrust receiving member and the thrust bearing surface provided on the end surface of the shaft body face each other to form a thrust bearing surface. In a bearing device that constitutes a bearing and is provided with a communication groove on the inner circumferential surface of the housing that communicates fluid on both sides of the contact portion between the thrust receiving member and the housing, the communication groove extends from the side of the shaft body to the opposite side of the shaft body. A bearing device characterized in that the bearing device is inclined in the direction of rotation of the housing with respect to the shaft body.