JP2000004556A - Motor and heat sink device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor which does not generate problems in which oil is released from the bearing end of the opening side, when the oil in the bearing is expanded and thereby oil shortage occurs during contraction, at the motor of a heat sink for cooling semiconductor. SOLUTION: In a motor, including a heling bone type dynamic pressure generating grooves 13 formed at two positions of the opening side and bottom surface side of the internal circumference of sleeve, when the length of axial direction of the dynamic pressure generating grooves 13 which contribute to flow of oil is considered, an opening side dynamic pressure generating groove is set so that the length to the opening side from the top of a herring bone is longer than the length to the bottom surface side from the top, while the bottom surface side dynamic pressure generating groove is set such that the length to the opening side from the top of the herring bone is equal to the length to the bottom surface side from the top.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor using a dynamic pressure type fluid bearing and a heat sink device for cooling a semiconductor using the motor.

[0002]

2. Description of the Related Art FIGS. 3 and 4 show the structure of a conventional heat sink device using a motor of a dynamic pressure type fluid bearing.

FIG. 3 is a sectional view showing a conventional heat sink device for cooling semiconductors, and FIG. 4 is an enlarged sectional view of a bearing portion of a motor used in the conventional heat sink device.

As shown in FIG. 3, around a cup-shaped frame housing 1a protruding from a concave portion of the frame 1, a drive circuit board 4 provided with a hall element and the like on a stator 3 on which a coil 2 is wound. Is installed. The stator 3 is fixed to an outer peripheral portion of the frame housing 1a, and an insulating sheet 7 is provided between the drive circuit board 4 and the frame 1. Also, the frame housing 1a
A thruster 5 made of resin or the like is fixed to a bottom surface of the frame 1, and a bell mouth 19 for smoothing the flow of air is fixed to an upper surface of the frame 1. The sleeve 6 is press-fitted and fixed to the frame housing 1a to form the stator unit 15.

A shaft 9 is integrally formed with the fan 8, and the shaft 9 abuts on the thruster 5 and is rotatably fitted into the sleeve 6. The fan 8 has a magnet 11 and a magnet yoke 1 that face the annular stator 3.
2 are fixed to form the rotor 16.

As shown in FIG. 4, a dynamic pressure generating groove 13 is formed on the inner peripheral surface of the sleeve 6 by ball rolling or the like. Further, a protrusion generated by the ball rolling is removed to reduce the inner diameter of the sleeve to ± 2 μm. Sizing is performed to finish with the following high precision. The dynamic pressure generating grooves 13 are formed at two locations in a herringbone shape, and the axial length from the vertex to the end of the herringbone is symmetric at both locations.

An oil 14 is lubricated into the dynamic pressure generating groove 13 as a lubricating oil, and constitutes a radial bearing 17. The end surface of the shaft 9 on the side opposite to the fan 8 is finished to a spherical surface, and comes into contact with the thruster 5 to contact the thrust bearing 1.
8.

[0008]

However, such a conventional electric motor has the following problems. 2. Description of the Related Art In recent years, electronic devices such as personal computers and home appliances have increased heat generation due to high performance and miniaturization, and accordingly, electric motors such as heat sink devices and cooling fan motors attached to electronic devices have large temperature changes. It is often placed under the environment.

When the electric motor is frequently placed in an environment having a large temperature change, the oil 14 in the bearing or the air layer in the oil repeats expansion and contraction. Outflow from the side bearing end face,
There was a problem of insufficient oil when shrinking. As a result, eventually, the bearing always runs short of oil, causing a decrease in the number of revolutions, an increase in the current value, and generation of abnormal noise.
Locking of the rotor 16 has occurred and reliability has been impaired.

Accordingly, an object of the present invention is to provide an electric motor capable of preventing oil from flowing out of a bearing during rotation.

Another object of the present invention is to provide a heat sink device using the electric motor and having high cooling efficiency.

[0012]

In order to solve this problem, an electric motor according to the present invention comprises a frame having a frame housing having one end opened and the other end sealed using the same member or another member. A stator fitted to the frame, a sleeve fitted in the frame housing, a shaft rotatably fitted in the sleeve, and a rotor having a magnet arranged opposite to the stator, and a gap between the shaft and the sleeve. Oil on the opening side and bottom side of either the inner peripheral surface of the sleeve or the outer peripheral surface of the shaft.
A dynamic pressure generating groove is formed at the location, the dynamic pressure generating groove on the opening side is formed so that oil flows toward the bottom side, and the dynamic pressure generating groove on the bottom side has a uniform oil flow toward the bottom side and the opening side It is formed so that it becomes.

As a result, oil flows to the bottom side in the dynamic pressure generating groove on the opening side, and the oil flow in the dynamic pressure generating groove on the bottom side is uniform. The oil flows to the side, and when viewed comprehensively, the oil flows are balanced and the oil can be prevented from flowing out from the end face of the opening-side bearing.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a frame provided with a cylindrical frame housing having one end opened, a stator attached to an outer peripheral portion of the frame housing, and A sleeve mounted in the cylindrical portion of the frame housing, a shaft rotatably fitted in the sleeve, a rotor having a magnet arranged opposite to the stator, and a gap between the shaft and the sleeve filled. An oil motor, wherein two dynamic pressure generating grooves are formed on one of an inner peripheral surface of the sleeve and an outer peripheral surface of the shaft, and the dynamic pressure generating groove is located on an opening side of the frame housing. The pressure generating groove is an electric motor formed so that the oil flows toward the bottom surface side of the frame housing. The oil flow is uniform in the dynamic pressure generating groove on the bottom side, but when the temperature becomes high, the oil flows to the opening side due to expansion of the air layer etc., and the oil flow is balanced when viewed comprehensively This has the effect of preventing the oil from flowing out of the bearing end surface on the opening side.

According to a second aspect of the present invention, there is provided the electric motor according to the first aspect, wherein the dynamic pressure generating groove has a herringbone shape, and the oil flow is smooth. Has an action.

According to a third aspect of the present invention, in the second aspect of the invention, the dynamic pressure generating groove located on the opening side of the frame housing is such that the width of the herring bone on the opening side from the vertex of the herring bone has a bottom surface. The width of the herringbone on the bottom side is equal to the width of the herringbone on the bottom side, which is longer than the width of the herringbone on the side, and the dynamic pressure generating groove located on the bottom side of the frame housing has the same width as the herringbone on the opening side from the vertex of the herringbone. By adjusting the length of the herringbone-shaped dynamic pressure generating groove, the flow of oil in the dynamic pressure generating groove on the opening side and the oil flow in the dynamic pressure generating groove on the bottom side are balanced, and the oil flows from the bearing end face on the opening side. Has the effect of preventing outflow.

According to a fourth aspect of the present invention, there is provided the electric motor according to any one of the first to third aspects, wherein a vent hole is formed on a bottom side of the frame housing. It is easy to insert the shaft into the sleeve at the time of assembly, it is difficult to accumulate the air layer in the oil,
It has the effect of reducing the pressure change in the bearing due to the temperature change and preventing oil from flowing out from the bearing end face on the opening side.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the ventilation hole is provided in an inner wall of the frame housing or an outer peripheral surface of the sleeve. The electric motor according to claim 4, wherein the electric motor is formed by a groove extending to the outside, and has an effect that the ventilation hole can be easily formed.

According to a sixth aspect of the present invention, in accordance with the first aspect of the present invention, there are provided two sets of dynamic pressures on the outer peripheral surface of the shaft or the inner peripheral surface of the sleeve. The electric motor according to any one of claims 1 to 5, wherein an oil pool that holds oil is formed between the generation grooves, and retains excess oil in the dynamic pressure generation grooves and runs out of oil in the dynamic pressure generation grooves. In this case, there is an effect that oil is supplied to the dynamic pressure generating groove by surface tension.

According to a seventh aspect of the present invention, in the first aspect of the present invention, at least one of a sleeve and a frame housing holds oil on the bottom side of the frame housing. The electric motor according to any one of claims 1 to 6, wherein an oil pool is formed, the motor holding surplus oil in the dynamic pressure generation groove,
When the oil in the dynamic pressure generating groove runs short, the oil is supplied to the dynamic pressure generating groove by surface tension.

According to an eighth aspect of the present invention, there is provided a heat sink apparatus provided with the electric motor according to any one of the first to seventh aspects, wherein a frame of the electric motor is capable of mounting a heating element. In addition, the heat of the heating element is directly conducted by the frame of the electric motor, and the frame performs a heat radiating action, and the air flow generated by the fan efficiently hits the frame to enhance the heat radiating effect.

According to a ninth aspect of the present invention, there is provided the heat sink device according to the eighth aspect, wherein plate-shaped or column-shaped fins are erected on the frame of the electric motor, and the fins have a function of increasing heat radiation efficiency.

According to a tenth aspect of the present invention, there is provided the heat sink apparatus according to the ninth aspect, wherein one or more openings are provided in a side wall of the frame of the electric motor, and the position, size, and number of the openings are determined. Optimum operation has the effect of directing the flow of air to other heating elements and smoothly exhausting high-temperature air.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In these drawings, the same members are denoted by the same reference numerals, and duplicate description is omitted.

(Embodiment 1) FIG. 1 is a sectional view showing a heat sink device according to Embodiment 1 of the present invention, and FIG. 2 is an enlarged sectional view of a bearing portion of a motor used in the heat sink device according to Embodiment 1 of the present invention. It is.

The motor according to the present embodiment, including the embodiments described below, is used in a human sink device for cooling semiconductors, and the same components as those in the conventional technology are denoted by the same reference numerals. Is given.

In FIG. 1, a drive circuit board 4 having a hall element and the like mounted on a stator 3 around which a coil 2 is wound is installed around a cup-shaped frame housing 1a formed so as to protrude from a concave portion of the frame 1. ing. A plate-shaped or pin-shaped fin 10 is provided upright in the concave portion of the frame 1, and a predetermined number of openings (not shown) through which air flows through the side wall are formed in a predetermined direction in a predetermined direction. Is provided. Further, the bottom of the frame 1 on the side where the frame housing 1a is not provided has a flat area to which a heating element such as a semiconductor element can be attached. The stator 3 is fixed to an outer peripheral portion of the frame housing 1a, and an insulating sheet 7 is provided between the drive circuit board 4 and the frame 1. A sleeve 6 is fitted into the frame housing 1a, a thruster 5 made of resin or the like is installed on the bottom surface of the frame housing 1a, and a bell for smoothing the air flow is provided on the upper surface of the frame 1. The mouse 19 is fixed and forms the stator unit 15.

A shaft 9 is integrally formed with the fan 8, and the shaft 9 is rotatably fitted in the sleeve 6 in contact with the thruster 5. A magnet 11 and a magnet yoke 12 are fixed to the fan 8 by bonding or the like so as to face the annular stator 3, thereby forming a rotor 16.

As shown in FIG. 2, on the inner peripheral surface of the sleeve 6 which is substantially straight in the axial direction, dynamic pressure generating grooves 13 are formed at two places by ball rolling or the like. Removed protrusions and increase sleeve inner diameter ± 2μ
Sizing is performed to finish with high precision of not more than m. Oil 1 is used as a lubricating oil in the dynamic pressure generating groove 13.
4 is lubricated to form a radial bearing 17 while maintaining a bearing gap of 2 to 12 μm on one side from the shaft 9.

Further, between the frame housing 1a and the sleeve 6, a ventilation groove 1b extending from the opening of the frame housing 1a to the bottom surface is formed on the inner wall of the frame housing 1a.

Also, on the bottom surface of the frame housing 1a,
In the vicinity where the shaft 9 and the thruster 5 are in contact, a concave oil pool 1c is formed to hold excess oil.

Between the two dynamic pressure generating grooves 13,
A groove-shaped oil pool 9 is formed on the outer peripheral surface of the shaft 9 to retain excess oil.

Further, the tip of the shaft 9 is finished in a spherical shape, and is in contact with the thruster 5 to form a thrust bearing 18. Further, a taper 9 b whose diameter decreases from the inside of the sleeve 6 toward the end face of the shaft 9 on the opposite side of the fan 8 is formed at the tip of the shaft 9. This taper 9b is connected to the outer peripheral surface at an angle of 5 ° to 45 ° with respect to the axial direction.

The dynamic pressure generating groove 13 will be described in detail. The dynamic pressure generating groove 13 is two herringbone-shaped grooves, and the rotation of the shaft 9 causes the oil 14 to generate a flow along the herringbone-shaped groove. The oil 14 having no space generates pressure in the radial direction. Further, since the two herringbone grooves are processed with a single stroke, they are straight grooves in the axial direction, but do not contribute to the flow of the oil 14 and the generation of pressure. The axial length of the herringbone groove in the portion of the bearing gap contributing to the flow of the oil 14 that is sufficiently small (2 to 12 μm on one side) is the length of the herringbone groove on the opening side from the vertex of the herringbone to the opening side. (= Length d) is longer than the length from the vertex to the bottom side (= length e), and the bottom side herringbone groove is the length from the vertex of the herringbone to the opening side (= length f). And the length from the vertex to the bottom surface side (= length g) are set equal.

According to the electric motor having such a configuration, the oil 14 can flow to the bottom side in the herringbone groove on the opening side, and the flow of the oil 14 can be uniform in the ringbone groove on the bottom side. The flow of the oil 14 is generated toward the opening side due to expansion of the air layer or the like, and when viewed comprehensively, the flow of the oil 14 is balanced and it is possible to prevent the oil 14 from flowing out from the end face of the opening side sleeve.

Further, by providing the ventilation groove 1b, a change in the pressure difference between the inside and outside due to expansion of the air layer at a high temperature can be reduced, and the oil 14 can be prevented from flowing out from the end face of the opening side sleeve.

The oil 14 in the oil pool 1c on the bottom of the frame housing 1a is supplied to the inside of the bearing due to expansion of a high-temperature air layer, and the excess oil 14 inside the bearing is held in the oil pool 9a. Even if the required oil becomes short due to evaporation or the like, the surplus oil is sufficiently pooled in the oil pools 1c and 9a.
Excess oil is supplied to the bearing gap having a higher surface tension at any time, and it is possible to prevent a shortage of oil in the bearing.

Next, the operation of the heat sink device of the present embodiment will be described. When the motor rotates, the fan 8 also rotates, sucks air along the axis 9 of the motor, flows along the air flow path formed by the fins 10, and exhausts air from the opening provided in the side wall of the frame 1. Is done. At this time, the air flow removes heat from the frame 1 and the fins 10 to which the heat of the heating element is conducted, and performs a cooling action.
The direction of the opening on the side wall should be adjusted according to the electronic device using the heat sink device so that the air exhausted from the heat sink device is applied to other heating elements and the high-temperature air is smoothly exhausted from the electronic device. Open in one or more directions.

The shape of the fin 10 is not limited to a plate shape or a pin shape, but may be any shape having the same function and effect as a triangular shape, a wing shape, a spiral shape, a circular shape, a radial shape, and the like. When the size of the heat sink device is smaller than a predetermined size (40 mm square), the size of the motor is inevitably reduced, and as a result, the output of the motor is also reduced. Therefore,
In the above case, the wind generated by the electric motor and the fan is reduced, and when the fins are erected, the amount of air discharged is reduced, which may worsen the heat radiation effect.
As described above, when the size of the heat sink device is in the above range, it is preferable to improve the heat radiation effect by increasing the amount of air to be released without providing the fins.

The structure of the heat sink device, the structure of the electric motor used therein, the type of the electric motor, the structure of the bearing, the oil and the like are not limited to the contents of these embodiments, and various design changes are possible. Needless to say, In the above-described embodiment, the dynamic pressure generating groove 13 is formed on the inner peripheral surface of the sleeve 6.
The oil pool 1c may be provided on the sleeve 6 while the oil pool 1c is provided on the frame housing 1a. The oil pool 9a may be provided on the sleeve 6 but may be provided on the sleeve 6. 1b may be provided on the frame housing 1a, but may be provided on the sleeve 6.

[0041]

As described above, according to the present invention, the herringbone groove on the opening side allows the oil to flow to the bottom side, and the herringbone groove on the bottom side makes the oil flow uniform. When this happens, oil flows to the opening side due to expansion of the air layer and the like, and when viewed comprehensively, the oil flows are balanced and oil can be prevented from flowing out from the end face of the opening side sleeve.

As a result, a smooth operation can be performed, and an effective effect that a motor having high reliability and long life can be obtained can be obtained.

Further, by providing the ventilation groove, it is possible to adjust the change in the internal / external pressure difference due to expansion of the air layer at a high temperature to some extent, and it is possible to obtain an effective effect that oil can be prevented from flowing out from the end face of the opening side sleeve. Can be

The oil in the oil pool on the bottom surface of the frame housing is supplied to the inside of the bearing due to expansion of a high-temperature air layer or the like, and excess oil inside the bearing is held in the oil pool, and the necessary oil is removed. Even if it becomes insufficient due to evaporation, etc., since the excess oil is sufficiently pooled in the oil pool, the excess oil is supplied to the bearing gap having a higher surface tension at any time, thereby preventing the bearing from running out of oil. An effective effect is obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a heat sink device according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a bearing portion of the electric motor used in the heat sink device according to the first embodiment of the present invention.

FIG. 3 is a sectional view showing a conventional heat sink device for cooling semiconductors.

FIG. 4 is an enlarged sectional view of a bearing portion of a motor used in a conventional heat sink device.

[Explanation of symbols]

 Reference Signs List 1 frame 1a frame housing 1b ventilation groove 1c oil pool 2 coil 3 stator 4 drive circuit board 5 thruster 6 sleeve 7 insulating sheet 8 fan 9 shaft 9a oil pool 9b taper 10 fin 11 magnet 12 magnet yoke 13 dynamic pressure generating groove 14 oil 16 Rotor 17 Radial bearing 18 Thrust bearing 19 Bellmouth

Claims (10)

[Claims] A frame provided with a cylindrical frame housing having one end opened; a stator mounted on an outer peripheral portion of the frame housing; a sleeve mounted in a cylindrical portion of the frame housing; An electric motor comprising: a shaft rotatably fitted in a rotor; a rotor provided with a magnet opposed to the stator; and oil filled in a gap between the shaft and the sleeve. Two dynamic pressure generating grooves are formed on one of the peripheral surface and the outer peripheral surface of the shaft, and the dynamic pressure generating grooves located on the opening side of the frame housing are arranged such that the oil is directed toward the bottom side of the frame housing. An electric motor characterized in that it is formed so as to flow through the motor. 2. The electric motor according to claim 1, wherein the dynamic pressure generating groove has a herringbone shape. 3. The dynamic pressure generating groove located on the opening side of the frame housing, wherein the width of the herring bone on the opening side from the vertex of the herring bone is longer than the width of the herring bone on the bottom side.
3. The electric motor according to claim 2, wherein the width of the herringbone on the opening side is equal to the width of the herringbone on the bottom side from the apex of the herringbone. 4. The electric motor according to claim 1, wherein a ventilation hole is formed on a bottom side of the frame housing. 5. The electric motor according to claim 4, wherein the ventilation hole is provided in an inner wall of the frame housing or an outer peripheral surface of the sleeve, and is formed by a groove extending from an open end to a bottom surface of the frame housing. . 6. An oil pool for holding oil is formed between two dynamic pressure generating grooves on an outer peripheral surface of a shaft or an inner peripheral surface of a sleeve. The electric motor according to any one of the above. 7. An electric motor according to claim 1, wherein an oil pool for holding oil is formed on a bottom surface of at least one of the sleeve and the frame housing. . 8. A heat sink device provided with the electric motor according to claim 1, wherein a frame of the electric motor is capable of mounting a heating element. 9. The heat sink device according to claim 8, wherein plate-shaped or column-shaped fins are erected on a frame of the electric motor. 10. The heat sink device according to claim 9, wherein one or more openings are provided on a side wall of the frame of the electric motor.