JP2000320547A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure communication of a vent hole of gas, and attain improvement of a bearing in the point of its performance and reliability, in a motor having a dynamic pressure fluid bearing. SOLUTION: A radial/thrust bearing part is constituted by a shaft member 101, a thrust member 105, and a bearing member 103 loosely fitted to the shaft member 101 to be drilled into a gas vent hole 119 extended from an arranged end surface side of the thrust member 105 in the length direction of the shaft member 101. Here, a circular annular groove 120, communicating with the gas vent hole 119, is provided in an external peripheral part 103A of the bearing member 103.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a motor used for rotationally driving OA equipment or the like and having a hydrodynamic bearing.

[0002]

2. Description of the Related Art Conventionally, a bearing member used in a hydrodynamic bearing motor is disclosed in Japanese Patent Application Laid-Open No. 63-1886025.

FIG. 2 shows a structural view of the bearing member, and reference numeral 201 denotes a shaft member. A bearing member 203 is closed by the thrust member 205, the upper end surface of the shaft member 201 faces the thrust member 205, and a dynamic pressure generating groove 206 provided on a surface of the thrust member 205 facing the shaft member 201. Through the shaft member 201
A thrust hydrodynamic bearing is formed between the bearing and the upper end surface of the bearing. The herringbone groove 20 is provided on the outer peripheral surface of the shaft member 201.
Numerals 2 are provided at two places at an interval in the axial direction, and the outer peripheral surface of the shaft member 201 and the inner peripheral surface of the bearing member 203 constitute a radial hydrodynamic bearing.

[0004] On the inner diameter surface of the shaft member 203, a concave relief portion 217 is provided in the circumferential direction, and the concave relief portion 217 is provided.
And a recess 220 formed on the outer diameter side of the bearing member 203.
And a gas vent hole (air vent hole) 219 is provided between them so that the concave escape portion 217 communicates with the outside air. One of the gas ventilation holes 219 has an extension center line (length direction) toward the inner diameter side of the bearing member 203 with an inner diameter larger than the end edge of the inner diameter surface (the insertion portion of the thrust member 205) on the upper end surface side in the axial direction of the bearing member 203. The center line (length direction) of the other gas vent hole 219 extending toward the inner diameter side of the bearing member 203 extends obliquely outward through the inner diameter side from the inner diameter surface of the lower end surface side of the bearing member 203 in the axial direction. ing.

As described above, in Japanese Patent Application Laid-Open No. 63-186025, a gas vent hole 219 is formed in a bearing member 203 which is loosely fitted to a shaft member 201. The gas vent hole 219 can be drilled by extending outward through the inner diameter side of the bearing member 203, and drilling is performed in a direction from the inner diameter side to the outer diameter side of the bearing member 203. As a result, burrs (drilling debris) are not generated on the inner diameter surface of the bearing member 203.

[0006]

In the conventional construction, it is difficult to insert a drill into the inner diameter side of the bearing member when the inner diameter of the bearing member is small or when the length of the bearing member is long. Even if it is possible, it is necessary to reduce the processing angle of the gas ventilation hole extending obliquely outward with respect to the axis center of the shaft member. Therefore, depending on the shape of the bearing member, the thickness of the gas vent hole and the inner diameter surface forming the dynamic pressure bearing of the bearing member becomes thinner, and the accuracy of the inner diameter surface (for example, roundness or cylindricity).
And may affect the performance and reliability of the hydrodynamic bearing.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems. In the case where the inner diameter of the bearing member is small or the length of the bearing member is long, the means for communicating the gas vent hole can be easily obtained and the bearing member can be easily connected to the bearing. An object of the present invention is to provide a motor having a configuration effective for improving the performance and reliability of the bearing without affecting the accuracy.

[0008]

In order to achieve this object, a motor according to the present invention is provided with a shaft member, a thrust member, and a play member which is loosely fitted to the shaft member and extends in a longitudinal direction of the shaft member from an end face side on which the thrust member is provided. A radial and thrust bearing portion is constituted by a bearing member having a gas vent hole and a lubricant, and an annular groove communicating with the gas vent hole is provided on an outer peripheral portion of the bearing member.

With this structure, when the inner diameter of the bearing member is small or when the length of the bearing member is long, the means for communicating the gas vent holes can be easily obtained, and the accuracy of the bearing member to the bearing portion is not affected. A motor that is effective in improving the surface and reliability can be obtained.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The invention according to a first aspect of the present invention is directed to a shaft having a shaft member, a thrust member facing the shaft end of the shaft member, and a bearing portion facing the shaft member. A bearing member that is loosely fitted to a member, wherein the bearing member has a gas vent hole extending in a longitudinal direction of the shaft member from an end surface side on which the thrust member is disposed, and the shaft member and the bearing In a motor constituting a radial bearing portion and a thrust bearing portion via a lubricant in a gap between members and a gap between the shaft member and the thrust member, an annular groove communicating with a gas vent hole is formed in an outer peripheral portion of the bearing member. The radial bearing portion and the outside of the bearing member, and the thrust bearing portion and the bearing member when the inner diameter of the bearing member is small or the bearing member length is long in a small motor, a long motor, or the like. Outside It is possible to provide a means for performing the communication configuration not from the inner diameter side of the bearing member but from the end face side where the thrust member is provided to the outer peripheral portion in the longitudinal direction of the shaft member toward the annular groove in the longitudinal direction of the shaft member. This has the effect of preventing the occurrence of damping caused by burrs or air mixing when inserted into the member, or of releasing air mixed in the bearing portion during operation of the motor to improve the performance and reliability of the motor.

According to a second aspect of the present invention, at least one of the shaft member and the bearing member according to the first aspect is provided with a herringbone groove to form a radial hydrodynamic bearing. It has the effect of improving the performance of the bearing (for example, non-repetitive runout, jitter, vibration, etc.) by floating the rotating member by the pumping dynamic pressure generated by the herringbone groove of the bearing.

According to a third aspect of the present invention, a thrust dynamic pressure fluid bearing is formed by providing a dynamic pressure generating groove in at least one of the shaft end of the shaft member or the flat portion of the thrust member according to the first aspect. This has the effect of raising the rotating member by pumping dynamic pressure generated by the spiral groove of the thrust bearing during operation of the motor to improve the performance of the bearing (for example, non-repetitive runout, jitter, vibration, etc.).

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

FIG. 1A is a sectional view of a motor according to a first embodiment of the present invention, and FIG.
FIG. 1 shows a top view. In FIG. 1, the shaft member 101 functions as a bearing as a center shaft during the rotation of the motor, and is generally made of a SUS material. For example, SUS420J2 or the like, which is frequently used for shafts, can be used, and quenching is performed to secure hardness, which is preferable in terms of reliability. A herringbone groove 102 formed by etching or the like is recessed in the outer peripheral portion of the shaft member 101 and inserted into a bearing member 103.

The thrust member 10 is connected to the bearing member 103 in order to connect the concave relief 117 to the outside 118 of the bearing member.
A gas vent hole 119 extending in the longitudinal direction of the shaft member 101 from an end face side where the gas vent hole 5 is provided is formed, and an annular groove 120 for communicating with the gas vent hole 119 is formed in the outer peripheral portion 103.
A. As the material of the bearing member 103, brass or the like can be used, which is preferable because the shape can be easily cut. As a processing means of the annular groove 120 of the outer peripheral portion 103A of the bearing member, cutting by a lathe can be used, and as a processing means of the gas vent hole 119, drilling by a drill can be used. In particular, the processing of the gas vent hole 119 is not performed from the inner diameter side of the bearing member 103 but is performed in the longitudinal direction of the shaft member 103 from the end face side of the bearing member 103 where the thrust member 105 is provided. The drilling direction is set so as to be directed from the end face side of the inside of the bearing 117 where the thrust member 105 is disposed to the annular groove 120 of the outer peripheral portion 103A that comes into contact with the outside 118 of the bearing member. (Perforation debris) is not generated. In addition, the gas vent hole 119
Is formed substantially parallel to the center of the shaft of the shaft member 101, so that the thickness up to the bearing portion 103B of the bearing member 103 is made uniform, and the gas vent hole 119 and the bearing portion 1 of the bearing member 103 are formed.
The bearing member 1 can be formed by arbitrarily setting the distance from the bearing member 03B.
There is no influence on the roundness or cylindricity of the bearing portion 103B of No. 03. Further, by connecting the gas ventilation hole 119 to the annular groove, the processing stroke of the gas ventilation hole 119 can be shortened and the effect on the cutting tool can be reduced.

A gap between the bearing member 103 and the shaft member 101 is filled with a lubricant 104 to form a radial hydrodynamic bearing capable of rotating relative to each other. Note that the lubricant 104 is preferably a low-evaporating one in terms of reliability.

The thrust member 105 performs the function of a thrust bearing, and is made of a material that is hard in hardness. For example, ceramic or a hardened SK material is preferable in terms of reliability. A spiral groove 106 formed by etching or the like is recessed on one surface of the thrust member 105, is disposed on one side in the longitudinal direction of the bearing member 103, and faces the shaft end 101 </ b> A of the shaft member 101. Thrust member 10
A gap between the shaft member 5 and the shaft end portion 101A of the shaft member 101 is filled with a lubricant 104 to form a thrust hydrodynamic bearing capable of rotating relative to each other. As described above, the lubricant 104 is preferably a low-evaporating lubricant in terms of reliability.

The housing 107 fixes the bearing member 103 and the stator core 108, and is generally made of aluminum. For example, A5052 and ADC12
Is preferable because the shape can be used and the shape can be cut with high precision. Stator core 108 is formed of a stack of silicon steel plates having t = 0.2 to 0.5 mm, and has windings 109 wound thereon. The winding 109 is connected to the stator core 108 by an energizing action of an external circuit.
A CEW or UEW is generally formed of a copper wire.

The rotor hub 110 is fixed to the shaft member 101 and rotates around the shaft member 101, and is made of a martensitic or ferrite magnetic material. For example, generally SUS416 or S
US430F is available. Rotor magnet 11
Numeral 1 is fixed at a position facing the stator core 108 of the rotor hub 110, performs suction and repulsion by a magnetic field generated by the stator core 108, and performs an action of rotating the rotor hub 110 about the shaft member 101, and is made of a magnetic material. Be composed. For example, samarium cobalt or neodymium can be used, which is preferable from the viewpoint of improving motor characteristics.

[0020]

As described above, according to the present invention, the ventilation means between the inside of the bearing and the outside of the bearing member when the inner diameter of the bearing member is small or the length of the bearing member is long in a small motor or a motor having a long overall length. In the above method, gas vent holes (e.g., work with a drill) are not performed from the inner diameter side of the bearing member, and can be easily performed in the longitudinal direction of the shaft member from the end face side of the bearing member where the thrust member is provided. By setting the direction from the inside of the member to the annular groove on the outer peripheral portion, burrs (perforation debris) are not generated inside the bearing member. In addition, the gas vent hole is formed substantially in parallel with the shaft center of the shaft member to make the thickness of the bearing member up to the bearing portion uniform, and the distance between the gas vent hole and the bearing portion of the bearing member is reduced. By making the dimensions arbitrary, the performance and reliability of the bearing can be improved without affecting the roundness and cylindricity of the bearing.

Thus, it is possible to prevent the shaft member from being caught by the burrs when the shaft member is inserted into the bearing member via the lubricant and to prevent the occurrence of damping due to the incorporation of air, or to allow the air mixed into the bearing portion to escape during the operation of the motor. In addition, the annular groove on the outer peripheral portion of the bearing member can be easily cut by a lathe at the time of cutting the outer peripheral portion, and by communicating with the gas vent hole, the machining stroke at the time of machining the gas vent hole can be shortened to a cutting tool. An advantageous effect is obtained in that the influence of the influence is reduced and the processing time is shortened.

[Brief description of the drawings]

FIG. 1A is a sectional view showing a motor according to a first embodiment of the present invention. FIG. 1B is a top view of a thrust member according to the first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a conventional bearing member (dynamic pressure type bearing sleeve).

[Explanation of symbols]

 101 Shaft member 101A Shaft end 102 Herringbone groove 103 Bearing member 103A Outer peripheral portion 103B Bearing portion 104 Lubricant 105 Thrust member 106 Dynamic pressure generation groove 117 Concave relief 118 Outside bearing member 119 Gas vent hole 120 Annular groove

Continued on the front page F term (reference) 3J011 AA04 AA20 BA04 CA01 CA02 DA02 5H605 BB05 BB19 CC04 EB02 EB06 EB28 5H607 BB01 BB17 CC01 DD08 DD14 DD17 EE11 FF12 GG01 GG02 GG12 GG28

Claims (3)

[Claims] A shaft member, a thrust member facing a shaft end of the shaft member, and a bearing member having a bearing portion facing the shaft member and loosely fitted to the shaft member; Has a gas vent hole extending in the longitudinal direction of the shaft member from the end face side where the thrust member is provided, and has a gap between the shaft member and the bearing member and a gap between the shaft member and the thrust member. A radial bearing and a thrust bearing via a lubricant, wherein an annular groove communicating with a gas vent hole is provided in an outer peripheral portion of the bearing member. 2. The motor according to claim 1, wherein a herringbone groove is provided in at least one of the shaft member and the bearing member to form a radial hydrodynamic bearing. 3. The motor according to claim 1, wherein a dynamic pressure generating groove is provided on at least one of a shaft end of the shaft member and a plane portion of the thrust member to form a thrust dynamic pressure fluid bearing.