CN1201465C - Fluid dynamic pressure bearing motor - Google Patents

Abstract

The present invention relates to a fluid dynamic pressure bearing motor characterized by the following contents, which includes: a casing; a shaft sleeve; a core; a shaft with a plate type thrust bearing installed at the lower end and integrally formed therewith; a wheel shaft; a cover a plate; a plurality of ventilation holes vertically penetrating through the thrust bearing and allowing oil to flow up and down the thrust bearing. Therefore, the oil pressure between the fluid dynamic pressure bearing and the shaft will be kept balanced on the whole, and its lubricating performance is further improved, and the driving characteristics and vibration characteristics of the motor are more effectively improved.

Description

Hydrodynamic Bearing Motors

The present invention relates to a motor mounted on a small precision instrument, more specifically, a hydrodynamic pressure (hydrodynamic) that maintains a balanced axial pressure, enables a shaft sleeve to generate stable dynamic pressure, and improves vibration characteristics. ) bearing motor.

It is well known to those skilled in the art that a motor generally used in a precision device such as a hard disk drive requires not only high-speed driving force but also precise control.

Indispensable for this type of motor is the rotational load and the supporting force of the shaft. For this reason, recently, hydrodynamic bearings with a small driving load are often used as supporting members for supporting the shaft instead of conventional metal bearings or balls.

This hydrodynamic bearing motor requires oiling to rotate the rotating body at high speed.

And this kind of oil needs to be added between the shaft and the sleeve surrounding the outer periphery of the shaft to reduce the friction caused by the direct contact between the shaft and the sleeve, and the shaft must be located in the center of the sleeve .

Accompanying drawing 1 and accompanying drawing 2 are to represent traditional fluid dynamic pressure bearing electric motor, as shown in the figure, electric motor is made of following components: casing 100 and axle sleeve 110 and the fixed parts that are made of core 120, also have shaft 130, A rotating machine composed of a wheel shaft 140 and a magnet 150 .

The central part of the sleeve 110 is vertically penetrated, and the shaft 130 is inserted in the center, and the groove 111 required for generating dynamic pressure is provided on the inner diameter surface, so as to generate fluid dynamic pressure in the opposite direction of the shaft radius.

In particular, a disc-shaped thrust bearing 160 installed at the lower end of the shaft 130 that rotates together with the shaft 130 is installed on the inner diameter of the shaft sleeve 110; The core 120.

Moreover, grooves 161 required for generating dynamic pressure will be provided on the upper and lower segments of the thrust bearing 160 so as to generate fluid dynamic pressure in the axial direction.

The inner diameter of the lower end of the shaft sleeve 160 is isolated from the outside by the cover plate 170 , and the thrust bearing 160 is in contact with the upper section of the cover plate 170 .

And be inserted in described axle sleeve 110 inner diameter part, and axle 130 upper part that can rotate is equipped with wheel shaft 140, and this wheel shaft 140 has the cap shape that opens downwards, is provided with facing core 120 outer diameters on the inner diameter surface of extension end. Surface magnet 150.

In the structure having such characteristics, a fine oil gap G is formed between the inner diameter surface of the sleeve 110 and the shaft 130 and the thrust bearing 160, and a certain amount of oil is filled in this oil gap.

When the shaft 130 rotates, the oil in the oil gap G is collected in the groove 111 provided for generating dynamic pressure in the sleeve 110 and the groove 161 provided for dynamic pressure in the thrust bearing 160, so that the balance is always maintained. The oil gap G, so that the shaft 130 can be driven stably.

In the conventional fluid dynamic pressure bearing motor having such a structural feature, if the power supplied from the outside is transmitted to the core 120, the axle 140 to which the magnet 150 is attached is rotated by the mutual electromagnetic force between the core 120 and the magnet 150, and the set The shaft 130 at the hub 140 also rotates simultaneously.

When this motor is driven, the shaft 130 inserted into the inner diameter portion of the sleeve 110 is driven by fluid dynamic pressure generated between the inner diameter surface of the sleeve 110 and the dynamic pressure generating groove 111 formed on the outer diameter surface of the shaft 130. In the case of the 110 inner diameter surface, it can be rotated freely.

That is, when a certain amount of oil is supplied between the outer diameter surface of the shaft 130 and the inner diameter surface of the sleeve 110, and the shaft 130 is rotated, the oil flows along the dynamic pressure generating groove 111 formed in the inner diameter portion of the sleeve 110. Flow and generate dynamic pressure, thereby reducing the rotation load and realizing smooth high-speed rotation.

However, when the traditional fluid bearing motor with the above-mentioned structural features is driven under the condition of adding oil between the shaft 130 and the shaft sleeve 110 and needs to be lubricated, due to the thrust bearing 160 installed on the shaft 130, It is impossible to keep the oil flowing optimally.

Therefore, the oil pressure generated in each part of the shaft 130 and the sleeve 110 is different, and there is a disadvantage that the overall lubricating effect is lowered.

In addition, due to the instability of the lubrication characteristics, the coaxiality of the shaft will be staggered, which will not only increase the vibration characteristics of the NRRO and RRO of the motor, but also cause the instability of the motor drive.

The present invention was invented in order to solve the above disadvantages, and the object of the invention is to provide a fluid dynamic pressure bearing motor characterized by the following content: in the fluid dynamic pressure bearing motor, the lubrication acting between the bushing and the shaft The pressure is equalized as a whole to ensure stable driving of the hydrodynamic bearing motor.

In order to achieve the above object of the present invention, there is provided a fluid dynamic pressure bearing motor characterized by the following, which includes: a casing; is installed on the casing, and inserts a shaft at a central portion protruding upward in a tubular shape , and form the sleeve of the hollow shaft; the core installed on the outer cylindrical surface of the sleeve; vertically inserted on the hollow shaft of the sleeve, and the plate type thrust bearing is installed at the lower end, and formed with it One-piece shaft; mounted on the upper end of said shaft, and cylindrically attached to the inner end of the extended end extended downwards, the wheel shaft of the magnet generating electromagnetic force by interaction with the core; inserted into said shaft The lower end of the hollow shaft of the shaft sleeve is closed with a cover plate; several vent holes vertically penetrate the thrust bearing and allow oil to flow along the upper and lower directions of the thrust bearing.

Other objects, features and advantages of the present invention are more clearly described through the following related drawings.

Fig. 1 is the end view of the fluid dynamic pressure bearing motor adopting the conventional technology;

Fig. 2 is an exploded schematic diagram of the waist of Fig. 1;

Fig. 3 is an end view of the first embodiment of the fluid dynamic pressure bearing involved in the present invention;

Fig. 4 is the end view that the shaft of Fig. 3 is cut in half;

Fig. 5 is the end view of the second embodiment of the fluid dynamic pressure bearing motor related to the present invention;

Fig. 6 is an end view of the shaft of Fig. 5 cut in half;

The following is an explanation of the symbols of the main parts of the drawings:

10: Case 15: Magnet

16: Cover plate 20: Shaft sleeve

21: Shaft hollow 22: Groove required to generate dynamic pressure

30: Axle 40: Core

50: Shaft 51: Groove required to generate dynamic pressure

55: Thrust bearing G: Oil clearance

Accompanying drawing 3 or accompanying drawing 4 is the first embodiment of the fluid dynamic pressure bearing motor involved in the present invention, as shown in the figure, the fluid dynamic pressure bearing motor can be divided into a fixed member that maintains a fixed state and a power supply and is fixed by means of A rotating member in which the interaction between the members enables rotation.

In this fluid dynamic pressure bearing motor, the fixed member is constituted by the sleeve 20 and the casing 10 and the core 40 , and the rotating member is constituted by the shaft 50 and the hub 30 and the magnet 15 .

Further, a rotatable shaft 50 is inserted into the hollow shaft 21 penetrating and provided at the center of the boss 20 .

The sleeve 20 usually forms a groove 22 required for generating dynamic pressure on the inner diameter surface of the hollow shaft 21 , so as to generate fluid dynamic pressure in the radial direction of the shaft 50 .

While the shaft sleeve 20 and the shaft 50 are separated at a certain interval, an oil gap G will be provided, and oil needs to be added to the oil gap G to control the friction between the shaft sleeve 20 and the shaft 50 .

When the shaft 50 rotates, the oil flows in the direction of rotation of the shaft 50 to generate a certain oil pressure, and the shaft 50 will have the property of moving radially and axially due to the influence of this oil pressure.

Therefore, for the conventional technology, at least the grooves 51, 22 required for generating dynamic pressure will be provided on the shaft 50 and the outer diameter surface or the corresponding side of the inner diameter surface of the sleeve 20, so that the oil from the oil will be generated. The fluid dynamic pressure generated from the gap G to the axial radial direction will maintain a balanced oil gap G between the sleeve 20 and the shaft 50 .

Grooves 22 for generating fluid dynamic pressure in the radial direction of the shaft are usually provided on the outer peripheral surface of the shaft 50. If a groove for generating dynamic pressure is provided on the shaft 50 of the rotating member, the friction between the shaft 50 and the oil will be deepened. Since it acts as a rotational load, the inner diameter surface of the non-driving member bushing 20 is often provided with a dynamic pressure generating groove 22 for generating fluid dynamic pressure in the axial direction.

The core 40 of the winding coil that flows into the power supply from the outer periphery along the end will be installed on the outer diameter portion of the shaft sleeve 20, and this core 40 corresponds to the magnet 15 attached to the inner cylindrical surface of the wheel shaft 30 to be described later, Thereby by means of the interaction a given electromagnetic force will be produced.

And at the lower end of the shaft sleeve 20, the plate-type cover plate 16 will be attached with an adhesive to isolate the lower end of the hollow shaft 21 and the outside, and the shaft 50 with the thrust bearing 55 and the cover The upper section of the plate 16 makes contact.

Here, the thrust bearing 55 is the same as the fluid dynamic pressure in the axial direction generated by the dynamic pressure generating groove 21 formed in the bushing 20, and is a member required to generate the fluid dynamic pressure in the axial direction. Installed on the lower end of the shaft 50 .

And on the upper end of described axle 50 will be installed the cap-shaped wheel shaft 30 that magnet 15 develops downwards on the inner cylindrical surface of the extended end that the outer end is extended downwards, and the magnet 15 that is attached on the described wheel shaft 30 will face the outer cylindrical surface of the core 40 .

In the hydrodynamic bearing motor having such a structural feature, the shaft 50 is driven while rotating together with the wheel shaft 30 by the electromagnetic force generated by the interaction between the core 40 and the magnet 15 when a power source is supplied from the outside.

The above-mentioned structure is almost the same as that of a conventional fluid dynamic pressure bearing motor, but the present invention is preferable to make the oil filled in the oil gap G provided between the bushing 20 and the shaft 50, Even when the motor is driven, it can maintain the overall balanced pressure. A number of vent holes 56 must be provided on the shaft 50 to ensure smooth oil flow.

That is, as shown in FIG. 4 , a plurality of vent holes 56 vertically penetrating and having a predetermined diameter are provided at a certain distance on the thrust bearing 55 arranged at the lower end of the shaft 50 .

The vent hole 56 runs through at least one of the upper and lower parts of the thrust bearing 55, so that oil can circulate through the vent hole 56, so that the oil filled into the oil gap G will maintain an overall balanced pressure.

The fluid dynamic pressure bearing motor having such a structural feature, such as the power supplied from the outside is transmitted to the core 40, the axle 30 to which the magnet 15 is attached is rotated by the electromagnetic force generated by the interaction between the core 40 and the magnet 15, thereby The shaft 50 installed on the wheel shaft also rotates simultaneously thereupon.

When this motor is driven, the shaft 50 inserted into the inner diameter portion of the sleeve 20 is rotated by the oil filled in the oil gap G without contacting the inner diameter surface of the sleeve 20 .

At this time, generally there will be an axial pressure difference between the bushing 20 and the thrust bearing 55 , and if such a pressure difference in the axial direction occurs, the oil can be circulated through the vent hole 56 . A balanced pressure can thus be maintained.

That is, when the shaft 50 is rotated, the oil flows along the vent hole 56 provided in the thrust bearing 55, and will generate an overall balanced dynamic pressure, thereby reducing the rotational load of the shaft 50 and realizing smooth high-speed rotation at the same time. .

Accompanying drawing 5 and accompanying drawing 6 are the second embodiment of the fluid dynamic pressure bearing motor related to the present invention. As shown in the figure, a first vent hole 57 extending upward from the bottom and a second vent hole 58 extending horizontally from the upper end of the first vent hole 57 are provided at the center of the shaft 50 .

Here, the first ventilation hole 57 will be arranged at the central part of the shaft 50, while the inlet will be arranged at the bottom, and can be vertically extended to a predetermined height.

The second vent hole 58 is connected to the first vent hole 57 from the middle part of the shaft 50 that bears the maximum pressure, and is extended in the horizontal direction, so that the oil can circulate along the upper section of the shaft 50 with a small load, thereby increasing the oil pressure. balanced.

The fluid dynamic pressure bearing motor having such a structural feature that if the power supplied from the outside is transmitted to the core 40, the wheel shaft 30 attached with the magnet 15 will be rotated by the electromagnetic force generated between the core 40 and the magnet 15, thereby being mounted on the The shaft 50 on the axle 30 rotates accordingly.

When this motor is driven, the shaft 50 inserted into the inner diameter portion of the sleeve 20 is rotated without contacting the inner diameter surface of the sleeve 20 by the oil filled in the oil gap G.

At this time, due to the driving force of the motor, a pressure difference in the axial direction usually occurs between the bushing 20 and the thrust bearing 55, and if a pressure difference in the axial direction occurs, the oil can pass through the first vent hole 57 and the second air hole. The vent holes 58 are circulated to ensure equalization of pressure.

Therefore, when the motor is driven, the oil circulates along the first vent hole 57 and the second vent hole 58, thereby maintaining the overall balanced pressure of the oil.

In summary, the hydrodynamic bearing motor involved in the present invention can correct the pressure difference generated between the bushing 20 and the thrust bearing 55 through the vent hole 565758, thereby not only reducing the NRRO and RRO characteristics, but also can reduce the noise caused by the imbalance of oil pressure.

The present invention can not only maintain a balanced dynamic pressure state in the shaft sleeve 20 in the axial direction, but also generate stable dynamic pressure in the sleeve 20 .

Therefore, the present invention can not only prolong the service life of the product, but also more effectively improve the reliability of the product performance.

Claims (2)

1. fluid dynamic pressure bearing motor, it is characterized in that: it comprises: casing; Be installed on the described casing, and insert axle to the central portion of upper process, and form the axle sleeve of hollow shaft with tubulose; Be installed in the core of the outer cylinder of described axle sleeve; Vertically be inserted on the hollow shaft of described axle sleeve, and the sheet profile thrust bearing be installed in the bottom, and the axle that forms as one with it; Be installed in the upper end of described axle, and the terminal part inner cylinder of the prolongation end that prolongs downwards adhere to by and core between interaction produce the wheel shaft of the magnet of electromagnetic force; Described axle is inserted in the cover plate that the hollow shaft bottom of axle sleeve is sealed; The some air vent holes that vertically run through described thrust bearing and oil is flowed along the thrust bearing above-below direction, described some air vent holes are arranged on the thrust plate around axle.

2. fluid dynamic pressure bearing motor, it is characterized in that: it comprises: casing; Be installed on the described casing, and insert axle to the central portion of upper process, and form the axle sleeve of hollow shaft with tubulose; Be installed in the core of the outer cylinder of described axle sleeve; Vertically be inserted on the hollow shaft of described axle sleeve, and the sheet profile thrust bearing be installed in the bottom, and the axle that forms as one with it; Be installed in the upper end of described axle, and the terminal part inner cylinder of the prolongation end that prolongs downwards adhere to by and core between interaction produce the wheel shaft of the magnet of electromagnetic force; Described axle is inserted in the cover plate that the hollow shaft bottom of axle sleeve is sealed; Be through to the 1st air vent hole of certain altitude from described axle bottom; Prolong from described the 1st air vent hole, meanwhile, from the 2nd air vent hole that prolongs to horizontal direction of axle mid portion of pressure maximum.

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