JPH1169711A - Spindle motor and rotating equipment using the spindle motor as drive source for rotating body apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a normal/reverse rotation spindle motor or a rotating body apparatus, having the normal/reverse rotation spindle motor used as a drive source for the apparatus. SOLUTION: A shaft rotation type spindle motor is provided with a normal/ reverse rotation dynamic pressure bearing, which functions as a pump-in type dynamic bearing during normal rotation but functions as a pump-out type dynamic pressure bearing during the reverse rotation, as well as a bearing gap provided for performing the switching between the pump-in method and pump-out method and self-valves (16 to 22), which automatically operate for interrupting vent holes (12 to 15) with outdoor air and open these holes during reverse rotation. Then, a valve drive power as a shaft rotating force of the self-valve is converted into air pressure, by utilizing the phenomenon of a wind mill.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forward / reverse rotating spindle motor in which a rotor is supported on a stator by a dynamic pressure bearing, and a drive source for a rotating body such as a magnetic disk, an optical disk or a porin mirror. To a rotating body device.

[0002]

2. Description of the Related Art There are radial dynamic pressure bearings and thrust dynamic pressure bearings. Radial dynamic pressure bearings are basically
It has a shaft and a sleeve that rotatably supports the shaft, and a dynamic pressure generating groove for a radial bearing, for example, a herringbone groove, is formed on one of the outer peripheral surface of the shaft and the inner peripheral surface of the sleeve over the entire circumference. It is a thing. Further, the thrust dynamic pressure bearing basically has a disk-shaped thrust holding member fixed to the shaft and a disk-shaped thrust bearing member provided opposite to the thrust holding member. A dynamic pressure generating groove for a thrust bearing, for example, a herringbone groove is radially formed on one surface of one of the thrust bearing members.

[0003] The dynamic pressure bearing as described above has very excellent features as a small bearing, and is widely used in small high-speed rotating machines. However, the dynamic pressure bearing as described above is a mechanism that generates a dynamic pressure by converting rotational energy into pressure through frictional force by providing a shallow groove at an acute angle with respect to the rotational direction. There is a problem that it cannot be rotated. Recently, for example, a paper entitled “Forward and reverse rotation herringbone journal gas bearing using both pump-in type and pump-out type” (Paper No. 92-0550) and the same paper in Transactions of the Japan Society of Mechanical Engineers, Vol. Vol. 59, No. 568, entitled "Rotating Forward and Reverse Rotating Gas-Lubricated Disk Thrust Dynamic Pressure Groove Bearings" (Paper No. 9)
3-0465) was announced.

[0004] FIG. 92-0550 is a perspective view of a partial cross section showing the principle of a forward / reverse rotating radial dynamic pressure bearing. Reference numeral 31 denotes a herringbone dynamic pressure generating groove formed of a plurality of substantially V-shaped shallow grooves on the outer peripheral surface. Shaft,
A sleeve 32 rotatably supports the shaft 31.
Reference numeral 3 denotes a communication hole provided on the wall surface of the sleeve 32 to the outside air. The conduction hole 33 is disposed so as to be located at the center of the herringbone dynamic pressure generation groove. In addition, a plurality of, for example, three conductive holes 33 are provided at equal angular intervals. This forward / reverse rotating radial dynamic pressure bearing uses a pump-in system that pushes the lubricating gas into the bearing depending on the direction of rotation and raises the pressure inside the bearing. It functions as a bearing by switching the pump-out system that generates high pressure by resistance.

[0005] Switching between the pump-in system and the pump-out system is realized by providing a forward / reverse switching valve (not shown) in the communication hole 33 with the outside air. In other words, in the case of forward rotation, the forward / reverse switching valve is closed to shut off the communication hole 33 to the outside air, and the pump functions as a pump-in type bearing that pushes the working gas into the bearing clearance by the pump-in effect to generate a positive pressure. In the case of reverse rotation, the valve is opened to open the communication hole 33 to the outside air, the working gas is sucked into the bearing clearance through the communication hole 33 by the pump-out effect, and a flow toward the shaft end is generated. It functions as a pump-out type bearing that generates pressure.

FIG. FIG. 93 is a diagram showing the principle of a forward / reverse rotation thrust dynamic pressure bearing described in 93-0465;
Is a disk-shaped thrust bearing member having a radial herringbone dynamic pressure generation groove G formed of a plurality of shallow grooves having a substantially L-shape on the upper surface, and 42 is a through hole provided in the center of a disk-shaped thrust bearing member 41. , 43 are disk-shaped thrust bearing members 41
A plurality of, for example, three, holes are provided on the same circumference, which is the boundary between the inner groove and the outer groove of the dynamic pressure generating groove G, and at equal angular intervals. ing. A disc-shaped thrust holding member (not shown) is coaxially fixed to an end of a rotary shaft (not shown), and a surface facing the disc-shaped thrust bearing member 41 is a smooth surface.

[0007] A forward / reverse switching valve (not shown) is provided in the through hole 43 to the outside air. The forward / reverse switching valve is provided with a through hole 43 so that the outside air flows only in a direction in which the outside air is sucked into the bearing.
To shut off or open. When the disc-shaped thrust pressing member on the smooth side rotates forward, a force for flowing the lubricating gas in the direction toward the conduction hole 43 is exerted due to the rotation direction and the inclination of the groove. As a result, the bearing clearance becomes high pressure and functions as a pump-in type bearing. Also, when the disc-shaped thrust holding member on the smooth side rotates in the reverse direction, the lubricating gas is caused to flow in the direction from the conduction hole 43 toward both the inner peripheral side and the outer peripheral side shaft end in the opposite direction to the forward rotation. At this time, since the forward / reverse switching valve is open, outside air flows into the bearing clearance through the through hole 43, and further flows toward the inner and outer peripheral shaft ends. A pressure is generated because the smooth portion of the member acts as a resistance to the flow, and functions as a pump-out type bearing.

[0008]

As described above, both the forward / reverse rotating radial dynamic pressure bearing shown in FIG. 4 and the forward / reverse rotating thrust dynamic pressure bearing shown in FIG. It functions as a bearing, and in the case of reverse rotation, it functions as a pump-out type bearing.However, switching between the pump-in type and the pump-out type is performed by reversing the opening and closing of the conduction hole between the bearing clearance and the outside air. This is performed by a switching valve.
The through hole 33 in FIG. 4 is formed on the wall surface of the sleeve 32 as a fixing member, and the through hole 43 in FIG.
Is formed on a disk-shaped thrust bearing member 41 which is also a fixing member. Therefore, these conduction holes 33 to 4
It is not difficult in design to provide a forward / reverse switching valve in 3.

For example, in a spindle motor employing a forward / reverse rotation bearing provided with a forward / reverse switching valve, an on / off solenoid valve is used for the forward / reverse switching valve, and is interlocked with a forward / reverse switching switch of the motor. The on / off solenoid valve may be driven. However, the solenoid valve is not bulky and inexpensive even if it is small. In addition, the cost is further increased by including the control circuit of the solenoid valve. For this reason, conventional forward / reverse rotating hydrodynamic bearings are more expensive than one-way rotating hydrodynamic bearings, and the structure is considerably complicated.
For this reason, there is no practical thing yet. For this reason, not only a forward / reverse rotating spindle motor using a dynamic pressure bearing, but also a rotating body device using this as a driving source of the rotating body has not been put to practical use yet.

Accordingly, an object of the present invention is to provide a forward / reverse rotating spindle motor in which a rotor is supported on a stator by forward / reverse rotating dynamic pressure bearings, and to drive the rotating body such as a magnetic disk, an optical disk, or a polygon mirror using the forward / reverse rotating spindle motor. An object of the present invention is to provide a rotator device used as a source. Another object of the present invention is a practical forward / reverse rotating radial dynamic pressure bearing having a self-valve that is inexpensive, simple in structure, and easy to maintain as a pump-in and pump-out switching valve,
Forward / reverse rotation thrust dynamic pressure bearing, or forward / reverse rotation spindle motor with forward / reverse rotation dynamic pressure bearing combining them,
Another object of the present invention is to provide a rotating body device using the forward / reverse rotating spindle motor as a driving source of the rotating body.

[0011]

SUMMARY OF THE INVENTION The present invention provides a spindle motor in which a rotor is supported on a stator by forward and reverse rotating dynamic pressure bearings.
Alternatively, in the rotating body device using the spindle motor as a driving source of a rotating body, a cylindrical first bearing member press-fitted and fixed to the forward / reverse rotating dynamic pressure bearing coaxially with a shaft; A second bearing member provided with a bearing clearance between the columnar first bearing member, and a dynamic pressure generating groove formed on one of the surfaces of the first bearing member and the second bearing member provided with the bearing clearance A conduction hole formed in the shaft and the first cylindrical bearing member so as to communicate with the bearing clearance from a lower end of the shaft;
And a self-valve fixed to the lower end of the shaft and automatically closing or opening the conduction hole in response to forward or reverse rotation. The forward / reverse rotation dynamic pressure bearing is configured as a cylindrical bearing member in which the second bearing member is erected on the base plate and the cylindrical first bearing member is coaxially inserted. The forward / reverse rotary dynamic pressure bearing uses a donut-shaped upper thrust holding member and a lower thrust holding member fixed to the base plate opposite to both ends of the cylindrical first bearing member on the second bearing member. Was configured.

Further, the present invention provides a spindle motor in which a rotor is supported on a stator by a forward / reverse rotating dynamic bearing, or a rotating device using the spindle motor as a driving source of a rotating body, wherein the dynamic bearing is coaxial with a shaft. And a cylindrical bearing member erected on the base plate and inserted coaxially with the cylindrical bearing member, and a donut disk-shaped member disposed at both ends of the cylindrical bearing member. An upper thrust holding member and a lower thrust holding member; a dynamic pressure generating groove for a radial bearing formed on one of an outer peripheral surface of the cylindrical bearing member and an inner peripheral surface of the cylindrical bearing member; Dynamic pressure generating grooves for thrust bearings formed on either end face of the bearing member, one of the upper thrust holding member and the lower thrust holding member, and a lower end of the shaft And a self-valve that is fixed to the lower end of the shaft and shuts off or opens the through-hole corresponding to normal rotation or reverse rotation. .

Further, in the present invention, a cap member for covering the lower end of the shaft with the self-valve, a valve seat formed at a lower end of the shaft, and a valve which is housed in the cap member and receives wind pressure. When the cap is seated on the valve seat and is not receiving wind pressure, the cap is configured by a vertically movable valve body that falls under its own weight and separates from the valve seat, and generates the wind pressure in one of normal rotation and reverse rotation. A through hole was provided in the member.

[0014]

According to the present invention, in a spindle motor in which a rotor is supported on a stator by a forward / reverse rotating dynamic pressure bearing, or in a rotating device using the spindle motor as a driving source of a rotating body, the dynamic pressure bearing includes a rotating force of a rotating shaft. Is converted into wind pressure using the phenomenon of a wind turbine, and the self-switching valve of the switching valve shuts off or opens the conduction path between the bearing clearance and the outside air according to the presence or absence of this wind pressure. Practical forward / reverse rotating dynamic pressure bearings that immediately and automatically switch over, ie, forward / reverse rotating radial dynamic pressure bearings, forward / reverse rotating thrust dynamic pressure bearings, or a combination of radial dynamic pressure bearings and thrust dynamic pressure bearings. Since it functions as a reverse rotation dynamic pressure bearing, the spindle motor or the rotating body device smoothly rotates in either the forward rotation or the reverse rotation while maintaining the characteristics of the dynamic pressure bearing. Further, the conduction path switching valve for the forward / reverse rotation dynamic pressure bearing,
At the time of forward rotation, the rotational force of the rotating shaft is pushed up by the wind pressure generated by utilizing the phenomenon of the windmill, and the inner valve is seated on the valve seat, and at the time of reverse rotation, the inner valve is dropped by its own weight and detaches the inner valve from the valve seat. It has a vertically movable valve, and functions as a practical self-valve that immediately and automatically switches between the forward-reverse rotating dynamic pressure bearing between the pump-in system and the pump-out system.

[0015]

FIG. 1 is a sectional view of a rotary device having a forward / reverse rotating spindle motor according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a base plate, and 2 denotes a cylindrical support member erected on the base plate 1. Reference numeral 3 denotes a cylindrical bearing member integrally formed with the cylindrical support member 2, and reference numeral 4 denotes a radial bearing having a shaft mounting hole at the center and an outer peripheral surface of which is provided between the inner peripheral surface of the cylindrical bearing member 3. The cylindrical bearing member 5 arranged so as to provide a clearance and the donut 5 arranged so as to provide a thrust bearing clearance with the upper end surface of the cylindrical bearing member 4 and supported by the upper end portion of the cylindrical support member 2. A disk-shaped upper thrust holding member; and 6, a donut disk-shaped lower thrust arranged so as to provide a thrust bearing clearance between itself and the lower end surface of the cylindrical bearing member and supported by the lower end of the cylindrical support member 2. Push For example a member.

Reference numeral 7 denotes a stator coil mounted on the outer peripheral surface of the cylindrical support member 2, and reference numeral 8 denotes a rotor magnet that generates a rotational force in cooperation with the stator coil 7. Reference numeral 9 denotes a cylindrical bearing member 4 which is press-fitted into a shaft mounting hole of the cylindrical bearing member 4.
The shaft 10 is coaxially fixed to the shaft 9. The shaft 10 is coaxially fixed to the upper end of the shaft 9 and is a rotating body supporting device also serving as a substantially cup-shaped hub having a rotor magnet 8 attached to the inner peripheral surface thereof. The structure and dimensions of the hub 10 are determined according to the rotating body to be supported, that is, a magnetic disk, an optical disk, a porin mirror, or the like.

The gap between the inner peripheral surface of the cylindrical bearing member 3 and the outer peripheral surface of the cylindrical bearing member 4 forms a radial bearing clearance. The gap between the upper end surface of the cylindrical bearing member 4 and the lower surface of the donut-shaped upper thrust holding member 5 and the gap between the lower end surface of the cylindrical bearing member 4 and the upper surface of the donut-shaped lower thrust holding member 6 are: Each forms a thrust bearing clearance. A dynamic pressure generating groove for a forward / reverse rotating radial bearing, for example, a herringbone groove as shown in FIG. 4 is formed on one of the inner peripheral surface of the cylindrical bearing member 3 and the outer peripheral surface of the cylindrical bearing member 4. I have. Further, a dynamic pressure generating groove for a forward / reverse rotating thrust bearing, for example, a herringbone groove as shown in FIG.
Either the upper surface of the cylindrical bearing member 4 or the lower surface of the donut-shaped upper thrust holding member 5, or the lower surface of the cylindrical bearing member 4 or the upper surface of the donut-shaped lower thrust holding member 6. Each is formed on one surface.

Reference numeral 11 denotes a shaft 9 from the upper end of the hub 10.
Center hole for clamps drilled to a length of approximately 1 mm
Reference numeral 2 denotes a first conduction hole formed in the shaft 9 along the central axis from the lower end to the vicinity of the center. Reference numeral 14 denotes second through holes radially bored in the cylindrical bearing member 4 for three radial bearing clearances, and correspond to the through holes 33 in FIG. Reference numeral 15 denotes a third through hole for three thrust bearing clearances formed in the cylindrical bearing member 4 in parallel with the central axis, and corresponds to the through hole 43 in FIG. 13 is shaft 9
A fourth conduction hole formed across the center axis to connect the second conduction hole 14 and the third conduction hole 15 to the first conduction hole 12. FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1 and viewed from the direction of the arrow in order to easily understand the arrangement relationship of the first to fourth conduction holes.

Reference numeral 16 denotes a valve seat formed at the lower end of the shaft 9 and thus at the lower end of the first conduction hole.
, And a substantially conical or hemispherical inner valve that is separated from the valve seat 16 when opened, 18 is a substantially column-shaped vertically movable valve body integrally formed with an inner valve 17 at an upper end, and 19 is a vertically movable valve body. 1
8 is a stopper formed integrally with the lower end of the stopper 8. Reference numeral 20 denotes a cap for accommodating the vertically movable valve element 18. A through hole 21 is formed in the vicinity of the cap surface, and the open end thereof is fitted into the lower end of the shaft 9 and fixed by an adhesive seal 22. The up-down movable valve element 18 is made of a resinous, light and slippery material. The cap 20 is also made of the same material as the vertically movable valve element 18. The stopper 19 forms a space serving as a wind pressure generation chamber between the inner surface of the cap 20 and the lower end of the vertically movable valve body 18, and has a length such that the vertical movement amount of the vertically movable valve body 18 is suppressed to, for example, about 0.5 mm. Has been chosen. The valve seat 16 and the inner valve 17 constitute a valve, and the vertically movable valve element 18 and the cap 20 constitute a valve drive section. Together, these constitute a self-directing forward / reverse switching valve.

As is apparent from FIG. 3, which is a sectional view taken along the line BB in FIG. 1 and viewed from the direction of the arrow, the through hole 21 is formed in the cap 20 at an angle equal to the same tangential direction of the inner circumferential circle thereof. Three are drilled at intervals. For this reason, when the cap 20 is rotating in the counterclockwise direction in FIG. 3, outside air flows into the wind pressure generation chamber from the through hole 21 to generate wind pressure. Conversely, when the cap 20 is rotating in the clockwise direction, no outside air flows into the wind pressure generating chamber from the through-hole 21, so that no wind pressure is generated. That is, a windmill phenomenon occurs depending on the rotation direction of the cap 20, and wind pressure is generated or not generated in the wind pressure generation chamber. Here, the above-described rotation direction in FIG. 3 is the same as that of the apparatus shown in FIG. 1 viewed from below. Therefore, when the apparatus shown in FIG. 1 is viewed from above, the above-described rotation direction is reversed. Therefore, when the spindle motor shown in FIG. 1 rotates forward, ie, clockwise, wind pressure is generated in the wind pressure generating chamber, and when it is rotated in the reverse direction, ie, counterclockwise, no wind pressure is generated in the wind pressure generating chamber.

In the present invention, a self-valve is used which utilizes the wind pressure as a valve driving force, and the self-valve immediately and automatically switches between a pump-in system and a pump-out system of a forward / reverse rotary dynamic pressure bearing. This is a forward / reverse switching valve.
That is, when the spindle motor rotates forward, the self-valve generates a wind pressure in the wind pressure generating chamber, and this wind pressure pushes up and down the movable valve body 18 to seat the inner valve 17 on the valve seat 16, thereby causing the first conduction. The conduction hole including the hole 12, the second conduction hole 14, the third conduction hole 15, and the fourth conduction hole 13 is closed. Accordingly, a radial bearing clearance formed between the inner peripheral surface of the cylindrical bearing member 3 and the outer peripheral surface of the cylindrical bearing member 4,
And between the upper end surface of the cylindrical bearing member 4 and the lower surface of the donut-shaped upper thrust holding member 5, and between the lower end surface of the cylindrical bearing member 4 and the upper surface of the donut-shaped lower thrust holding member 6, respectively. The thrust bearing clearance is shut off from the outside air. Then, a pump-in effect occurs in these bearing clearances, and the forward / reverse rotating dynamic pressure bearing of FIG. 1 functions as a pump-in type dynamic pressure bearing.

When the spindle motor rotates in the reverse direction, no wind pressure is generated in the wind pressure generating chamber of the self-valve, so that the vertically movable valve body 18 falls by its own weight, and the inner valve 17 is detached from the valve seat 16, whereby the first valve is released. Conducting hole 12, second conducting hole 1
4. The conduction hole including the third conduction hole 15 and the fourth conduction hole 13 is opened. Accordingly, the radial bearing clearance formed between the inner peripheral surface of the cylindrical bearing member 3 and the outer peripheral surface of the cylindrical bearing member 4, and the upper end surface of the cylindrical bearing member 4 and the donut disk-shaped upper thrust holding member 5. Thrust bearing clearances formed between the lower surface and between the lower end surface of the cylindrical bearing member 4 and the upper surface of the donut-shaped lower thrust holding member 5 are formed through the conduction hole and further within the cap 20 of the self-valve. It communicates with the outside air via a gap between the peripheral surface and the outer peripheral surface of the vertically movable valve element 18. Then, a pump-out effect occurs in these bearing clearances, and the forward / reverse rotating dynamic pressure bearing of FIG. 1 functions as a pump-out type dynamic pressure bearing. In this way, in the forward / reverse rotating dynamic pressure bearing of FIG. 1, the switching between the pump-in system and the pump-out system is performed immediately and automatically by the action of the forward / reverse switching valve of the self-valve utilizing the phenomenon of the windmill. Functions as a practical forward / reverse rotating dynamic pressure bearing.

With reference to FIG. 1, the structure and operation of the forward / reverse rotating hydrodynamic bearing having one radial hydrodynamic bearing and two thrust hydrodynamic bearings have been described in detail. However, the present invention is not limited to this, one with one radial hydrodynamic bearing, one with one thrust hydrodynamic bearing, or one with two thrust hydrodynamic bearings, Alternatively, a bearing having one radial dynamic pressure bearing and one thrust dynamic pressure bearing can be realized.

Referring to FIG. 1, an example of a forward / reverse rotation dynamic pressure bearing having one radial dynamic pressure bearing will be described. A cylindrical bearing member 4 having a shaft 9 coaxially press-fitted and fixed,
A cylindrical bearing member 3 erected on a base plate 1 and having a cylindrical bearing member 4 coaxially inserted therein; and formed on one of an outer peripheral surface of the cylindrical bearing member 4 and an inner peripheral surface of the cylindrical bearing member 3. Dynamic pressure generating grooves for the radial bearing, conduction holes 12 to 14 communicating from the lower end of the shaft 9 to the outer peripheral surface and both end surfaces of the cylindrical bearing member 4, respectively, and fixed to the lower end of the shaft 9 for normal rotation or And self-valves 16 to 22 for closing or opening the conduction hole in response to the reverse rotation. The thrust bearing in this case is, for example, a magnetic bearing or a slide bearing using a magnetic fluid. Naturally, a through hole (a through hole 15 in FIG. 1) for a thrust bearing clearance is not formed in the cylindrical bearing member 4. Also, the structure is different from that of the thrust bearing members such as the donut-shaped upper thrust holding member 5 and the lower thrust holding member 6.

An example of a forward / reverse rotating hydrodynamic bearing having two thrust hydrodynamic bearings will be described with reference to FIG.
A cylindrical bearing member 4 in which a shaft 9 is coaxially press-fitted and fixed; a cylindrical bearing member 3 erected on the base plate 1 and into which the cylindrical bearing member 4 is inserted coaxially; and both ends of the cylindrical bearing member 3 Donut-shaped upper thrust holding member 5 and lower thrust holding member 6, and thrust formed on either end face of the cylindrical bearing member 4 and one of the upper thrust holding member 5 and the lower thrust holding member 6. A dynamic pressure generating groove for the bearing, conductive holes 12 to 15 communicating from the lower end of the shaft 9 to the outer peripheral surface and both end surfaces of the cylindrical bearing member 4, respectively, and fixed to the lower end of the shaft 9 for normal rotation or reverse rotation. And self valves 16 to 22 for closing or opening the conduction holes. The radial bearing in this case is, for example, a magnetic bearing or a plain bearing using a magnetic fluid. Naturally, a conduction hole for the radial bearing clearance (a part of the outer peripheral surface side of the conduction hole 14 in FIG. 1) is a cylindrical bearing. It is not formed on the member 4 and the outer peripheral surface of the cylindrical bearing member 4 and the structures of the cylindrical bearing member 3 and the inner peripheral surface are different from those in FIG. Further, a forward / reverse rotation dynamic pressure bearing having one thrust dynamic pressure bearing or a forward / reverse rotation dynamic pressure bearing having one radial dynamic pressure bearing and one thrust dynamic pressure bearing is also the same as described above. It can be realized with a configuration.

[0026]

In the present invention, the forward / reverse rotation dynamic pressure bearing which is a bearing of the spindle motor or the spindle motor as a driving source of the rotating body has a radial bearing clearance and / or a thrust bearing clearance and a communication hole between the outside air. In the forward / reverse rotation dynamic pressure bearing, which is cut off at the time of forward rotation to function as a pump-in type dynamic pressure bearing, and is opened at the time of reverse rotation to function as a pump-out type dynamic pressure bearing, the conduction hole is cut off or Since the self-valve is used as the open / close switching valve, switching between the pump-in system and the pump-out system is performed immediately and automatically. In addition, the forward / reverse switching valve converts the rotational force of the shaft into a wind pressure utilizing the phenomenon of a windmill to obtain a valve driving force for shutting off the valve, and opens the valve by its own weight of the vertical movable valve body which is a valve driving means. It is a pure mechanical small and light self-valve with simple structure, reliable operation and easy maintenance. in this way,
The spindle motor according to the present invention or a rotating device using the spindle motor as a drive source is an extremely practical forward / reverse inexpensive, compact, simple in structure, and easy to maintain as compared with conventional ones. Since a rotatable dynamic pressure bearing is employed for the bearing, the size of the apparatus itself can be reduced, and the cost can be suppressed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a rotating device having a forward / reverse rotating spindle motor according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1 and viewed from the direction of the arrow.

FIG. 3 is a cross-sectional view taken along line BB in FIG. 1 and viewed from a direction of an arrow.

FIG. 4 is a diagram showing a basic structure of a forward / reverse rotation dynamic pressure bearing that functions as a pump-in type radial dynamic pressure bearing during forward rotation and as a pump-out type radial dynamic pressure bearing during reverse rotation.

FIG. 5 is a diagram showing a main part of a basic structure of a forward / reverse rotation dynamic pressure bearing that functions as a pump-in type thrust dynamic pressure bearing during forward rotation and as a pump-out type thrust dynamic pressure bearing during reverse rotation. is there.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base plate 2 Cylindrical support member 3 Cylindrical bearing member 4 Cylindrical bearing member 5 Donut board upper thrust holding member 6 Donut board lower thrust holding member 7 Stator coil 8 Rotor magnet 9 Shaft 10 Substantially cup-shaped hub 11 Center for clamp Hole 12 First conduction hole 13 Fourth conduction hole 14 Second conduction hole 15 Third conduction hole 16 Valve seat 17 Inner valve 18 Vertical movable valve element 19 Stopper 20 Cap 21 Through hole 22 Adhesive seal 31 Shaft 32 Sleeve 33 Conduction hole 41 Disc-shaped thrust bearing member 42 Through hole 43 Conducting hole G Dynamic pressure generating groove

Claims (6)

[Claims] 1. A spindle motor in which a rotor is supported on a stator by a dynamic pressure bearing, wherein the dynamic pressure bearing is fixed to a base plate and a first cylindrical bearing member having a shaft coaxially press-fitted and fixed to the base plate. A second bearing member provided with a bearing clearance between the bearing member, a dynamic pressure generating groove formed on one of the surfaces of the first bearing member and the second bearing member provided with the bearing clearance, and the shaft; And a conduction hole formed in the shaft and the first bearing member so as to communicate with the bearing clearance from the lower end of the shaft, and cuts off or opens the conduction hole fixed to the lower end of the shaft corresponding to forward rotation or reverse rotation. A forward / reverse rotating spindle motor characterized by a forward / reverse rotating dynamic pressure bearing comprising a self-valve. 2. The reciprocal bearing according to claim 1, wherein said second bearing member is a cylindrical bearing member erected on said base plate, and said cylindrical first bearing member is coaxially inserted. Rotary spindle motor. 3. The donut-shaped upper thrust holding member and the lower thrust holding member fixed to the base plate opposite to both ends of the cylindrical first bearing member. A forward / reverse rotating spindle motor according to claim 1. 4. A spindle motor in which a rotor is supported on a stator by a dynamic pressure bearing, wherein the dynamic pressure bearing is a columnar bearing member having a shaft coaxially press-fixed thereto, and a columnar bearing member standing upright on a base plate. A coaxially inserted cylindrical bearing member, a donut-shaped upper thrust holding member and a lower thrust holding member disposed at both ends of the cylindrical bearing member, an outer peripheral surface of the cylindrical bearing member and the cylindrical shape. A dynamic pressure generating groove for a radial bearing formed on one of the inner peripheral surfaces of the bearing member, and formed on one of the both end surfaces of the cylindrical bearing member, the upper thrust holding member, and the lower thrust holding member. Dynamic pressure generating groove for the thrust bearing, and conduction holes respectively communicating from the lower end of the shaft to the outer peripheral surface and both end surfaces of the cylindrical bearing member,
And a self-reversing rotary hydrodynamic bearing comprising: a self-valve fixed to the lower end of the shaft to close or open the conduction hole in response to normal rotation or reverse rotation. 5. The self-valve includes a cap member that covers a lower end of the shaft, a valve seat formed at a lower end of the shaft, and a valve seat that is housed in the cap member and receives wind pressure. A valve body that is seated and separates from the valve seat by its own weight when not receiving wind pressure, and a through hole formed in the cap member so as to generate the wind pressure in one of normal rotation and reverse rotation. The forward / reverse rotating spindle motor according to claim 1, 2, 3, or 4. 6. A spindle motor in which a rotor is supported on a stator by a dynamic pressure bearing, wherein the dynamic pressure bearing is fixed to a base plate, a columnar first bearing member having a shaft coaxially press-fitted and fixed to the base plate, and A second bearing member providing a bearing clearance between the first bearing member and a dynamic pressure generating groove formed on one of the surfaces of the first bearing member and the second bearing member providing the bearing clearance; A conduction hole formed in the shaft and the first bearing member so as to communicate with the bearing clearance from the lower end of the shaft, and the conduction hole is fixed to the lower end of the shaft and blocks the conduction hole corresponding to normal rotation or reverse rotation. A rotating device using a forward / reverse rotating spindle motor comprising a forward / reverse rotating dynamic pressure bearing including a self-valve that opens.