JP2001116054A - Oil seal mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil seal mechanism for enhancing sealing performance of oil by enhancing adhesion of a seal part for contacting with a sleeve end surface, and improving a shape of a seal ring and a stator fitted around the sleeve outer periphery in dynamic pressure bearing constitution. SOLUTION: In the shaft-fixed/sleeve-rotatable dynamic pressure bearing constitution, a motor and an oil dynamic pressure bearing are provided for preventing the outflow of oil from a shaft and a sleeve inner diameter by the seal part, preventing the outflow of oil from a thruster and a sleeve outer diameter by the seal ring, also preventing scattering oil to the outside of a dynamic pressure bearing by the seal part and the seal ring, and maintaining high performance for a long time by also having an oil reservoir.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the prevention and scattering of oil from a bearing portion of an oil dynamic pressure bearing structure in order to extend the life of the bearing of a small, flat and thin motor having an oil dynamic pressure bearing mechanism. The present invention relates to an oil seal mechanism having a prevention and an oil reservoir.

[0002]

2. Description of the Related Art Generally, in an oil dynamic pressure bearing structure of a fixed shaft and a rotary type sleeve, when the rotation speed of the sleeve is high, the centrifugal force acts greatly on the dynamic pressure oil in the bearing unit, and the outer periphery of the shaft is reduced. The oil easily flows out or scatters from the gap between the portion and the inner peripheral chamfered portion of the sleeve end face or the gap between the outer peripheral chamfered portion of the thruster and the outer peripheral chamfered portion of the sleeve (hereinafter, these two locations are referred to as a mouth). When oil flows out from the mouth, the oil runs out, that is, the inside of the sliding opposing surface between the shaft and the sleeve or the thruster and the sleeve is depressurized, so that the air near the mouth is drawn into the inside of the sliding opposing surface, and the air enters. As a result, oil film breakage occurs on the sliding facing surface. As the oil film runs out, friction occurs between the contact surfaces of the shaft and the sleeve or the thruster and the sleeve, and the frictional heat generated by the friction raises the temperature in the sleeve bearing and expands the entrapped air (bubbles). Due to the expansion of the bubbles, a vicious cycle often occurs in which the oil is further expelled from the oil dynamic pressure bearing portion.

Therefore, conventionally, even if oil is scattered, the oil is scattered and collected again and returned to the bearing sliding portion so that the dynamic pressure grooves are arranged in an unbalanced manner so that the dynamic pressure acts more inward. Many designs have been devised, and there have been devised ones in which a dynamic pressure groove for a pump-in is provided on the end surface of a sleeve or thruster to draw oil toward the inner peripheral side.

[0004]

However, in the former method, the inner side of the oil dynamic pressure bearing structure is moved from the outer peripheral side to the centrifugal force during the continuous rotation driving of the sleeve or in the absence of a force toward the center. It was impossible to return to the circumferential side.
In the latter method, the clearance between the shaft and the sleeve changes due to the temperature difference between the bearings with the passage of time, and the oil that has flowed out or the oil at the mouth from which the oil may flow out is not affected. The effect was questionable.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and has a fixed shaft having a cylindrical surface outer peripheral portion at a center position of a thruster, which serves as a base on a stator side. In an oil dynamic pressure bearing structure comprising a rotary sleeve formed in a substantially cylindrical shape and externally fitted to the fixed shaft and a substantially cylindrical rotor externally fitted and fixed to the sleeve, A seal function of preventing oil from flowing out of a gap between the outer peripheral surface of the shaft and the chamfered portion of the inner diameter of the sleeve by attaching an annular seal component provided at least on the inner diameter side of the end surface of the sleeve to the end surface of the sleeve. An oil reservoir is formed in a gap between the shaft outer peripheral surface and the sleeve inner diameter chamfered portion.

[0006] Further, the seal component has an annular contact flat portion which comes into contact with the sleeve end surface near the outermost periphery of the chamfer, and further, on the outer peripheral side from the contact flat portion, the sleeve end surface and the seal component are provided. Has a space for inserting an adhesive for tightly contacting the gap.

Further, the seal component has an annular substantially concave groove on a surface in contact with the sleeve end surface, and an annular elastic material is inserted into the groove portion so that the elastic material is provided on the sleeve end surface side. The oil seal effect is provided by pressing the insertion side.

Further, the seal component has a shape in which a part of an arc of an outer peripheral portion is cut out, and is fixed by press-fitting a part of the outer periphery of the seal component into the inner diameter surface of the rotor. The cutout outer peripheral part of the part has a partial gap with the inner diameter surface of the rotor, the excess of the adhesive overflows from the gap, and the excess adhesive pool is formed on the upper and lower end faces. is there.

[0009] The seal component may have an annular oil reservoir portion having an oil sealing effect in an annular shape, instead of the chamfer, on a surface that comes into contact with the outer peripheral surface of the shaft. .

[0010] Further, the seal component has an annular substantially convex portion on a surface in contact with the sleeve end surface, and further on the outer peripheral side of the substantially convex shape portion, the sleeve end surface and the seal component are separated from each other. This secures a space for inserting an adhesive for bringing the gap into close contact.

[0011] Further, the present invention provides an oil seal mechanism using the above-mentioned sealing part.

Further, in an oil dynamic pressure bearing structure formed of a fixed thruster and a rotary sleeve which are both formed in a substantially cylindrical shape and which are fitted to the shaft, the outer peripheral end surface of the rotary sleeve is When the seal ring is externally fitted, and when the seal ring is externally fitted to the outer peripheral end surface of the rotary sleeve, the seal ring has a shape protruding closer to the thruster than the sleeve end surface. A seal ring characterized by preventing oil scattering and outflow from a sliding portion gap portion between the fixed thruster outer chamfered portion and the rotary sleeve outer chamfered portion by centrifugal force, and the rotary sleeve and the rotary sleeve. An oil seal mechanism including a fixed thruster and the seal ring is provided.

Further, an inner surface of the seal ring has an annular substantially concave groove near the end surface of the rotary sleeve,
An annular elastic material is inserted into the groove portion, and an inner surface of the seal ring is pressed against an outer peripheral surface of the rotary sleeve, thereby providing an oil seal effect. is there.

The outer peripheral portion of the seal ring has an annular substantially convex portion. Further, the inner peripheral surface of the substantially cylindrical stator located on the outer periphery of the seal ring has an annular substantially convex shape. The concave portion is arranged at a height opposite to the substantially convex portion of the seal ring and wider than the substantially convex portion, and the centrifugal force generated by rotation of the rotary sleeve causes the substantially convex portion to move away from the substantially convex portion. An oil composed of a seal ring and a stator, wherein oil scattered in the circumferential direction of the seal ring is received by the substantially concave portion to prevent oil splattering outside the oil dynamic pressure bearing structure. A sealing mechanism is provided.

By configuring the above oil seal mechanism, an oil reservoir is provided at the mouth from which oil may flow out, and air does not come into contact with the mouth as long as there is oil in the oil reservoir. Even if oil flows in and out of the oil reservoir, it does not replace the air bubbles, so that the oil is retained in the bearing portion. In the unlikely event that the oil is replaced by air bubbles, the oil is driven out, but the oil does not flow out or scatter from the oil reservoir at the mouth to the outside. .

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view showing a configuration of an oil dynamic pressure bearing using an oil seal mechanism according to a first embodiment of the present invention. In this figure, the horizontal hatched portions such as the shaft 1 and the thruster 5 are the fixed portions as the stator, and the oblique hatched portions such as the cylindrical sleeve 2 are the rotating portions as the rotor.

The dynamic pressure grooves are formed with a herringbone dynamic pressure groove on the inner surface A of the sleeve 2 and a pump-in dynamic pressure groove (both not shown) on the end surface B of the thruster 5, and are formed in both radial and thrust directions. The rotor rotates without contact. Therefore, a small gap C exists between the outer peripheral surface of the shaft 1 and the chamfered portion of the inner diameter of the sleeve 2 in the upper part of FIG. Of course, oil is disposed in the gap between the outer peripheral surface of the shaft 1 and the inner peripheral surface of the sleeve 2.

Considering the operation of the oil dynamic pressure bearing without the annular seal part 3 shown in FIG. 1, the oil leaked from the gap C between the chamfered portion of the inner diameter of the sleeve 2 and the outer peripheral surface of the shaft 1 for some reason, such as oil expansion. Is scattered to the outer peripheral side of the sleeve 2 by centrifugal force generated by the rotation of the sleeve 2,
Further, it rises along the inner peripheral wall of the cylindrical rotor 4 located on the outer peripheral surface side of the sleeve 2 and scatters outside the oil dynamic pressure bearing 9.

When the shaft 1 and the sleeve 2 were actually constructed as shown in FIG. 1 and an experiment on oil outflow from the gap C was performed, the amount of oil outflow from the gap C was determined by the chamfer applied to the inner diameter of the sleeve 2. It turned out to be strongly influenced by size.

The seal component 3 is press-fitted and fixed to the inner surface of the rotor 4 so as to be in close contact with the upper end surface of the sleeve 2. In addition, the sealing part 3 has a surface on the side in close contact with the upper end surface of the sleeve 2,
The reversely tapered ring is formed, so that the oil blown to the outer peripheral side of the sleeve 2 by the centrifugal force acts on the reversely tapered portion downward, and does not flow upward from the uppermost portion of the seal component 3.

If oil is previously stored in a space 10 formed by the upper end surface of the sleeve 2, the outer peripheral surface of the shaft 1, and the seal part 3, if the seal part 3 does not have a reverse taper, the oil in the space 10 The flow may be spiral, and air may enter deeply in the vicinity of the outer peripheral surface of the shaft 1, but this can be suppressed by applying the reverse taper.

In this manner, the seal part 3 has a function of preventing oil from splashing on the oil pool portion and the upper part of the oil dynamic pressure bearing 9,
By not allowing air to flow into the inner diameter portion of the sleeve 2, the oil in the bearing portion of the sleeve 2 is not reduced, and the space 10
If not only oil but air is mixed in,
The sleeve 2 also has a function of replenishing oil in the bearing portion.

The seal part 3 has an annular contact flat portion 15 which is in close contact with the upper end surface of the sleeve 2 near the outermost periphery of the reverse taper.
The outer peripheral portion of the sealing part 3 has a sleeve 2
There is a space 11 surrounded by the upper end surface, the inner peripheral wall of the rotor 4 and the seal part 3, and a flexible adhesive or the like is buried in the space 11 so as to flow out of the upper end surface of the sleeve 2 by centrifugal force. Block the oil. Further, in order to further ensure the oil blocking function, an annular concave groove is formed in the surface on the side in close contact with the upper end surface of the sleeve 2, and a rubber packing 8 having a shape matching the concave groove is inserted therein. Pressing the sealing part 3 against the upper end surface of the sleeve 2 to bring the sealing part 3 into close contact therewith is more effective in providing an oil sealing effect.

FIG. 2B is a side sectional view showing a first embodiment of the seal component 3, which is designed according to the above description.
FIG. 2A is a plan view of FIG. 2B and shows the outer peripheral shape of the seal component 3 of the first embodiment. Positioning the outer periphery 12 by press fitting into the inner diameter of the rotor 4 prevents the inner diameter surface 13 of the seal component 3 from coming into contact with the shaft 1 to generate heat or emit abrasion powder, and completely solidifies the adhesive. The height position is maintained.

The cutout straight portion of the outer periphery 12 of the plan view of FIG. 2A is used to press-fit the seal part 3 into the inner diameter of the rotor 4 and adhere it to the upper end surface of the sleeve 2. FIG. 8 shows a first embodiment of a partial gap formed between the inner surface of the rotor 4 and an excess amount of the agent, which also has an escape when the adhesive expands.

FIG. 3 (b) is a side sectional view showing a second embodiment of the seal component, in which a U-shaped oil reservoir is provided on the inner surface of the seal component in an annular shape instead of the reverse taper. If the outer diameter of the entire motor on which the sealing parts are mounted is small and the height can be increased, it is effective to provide an oil sealing effect.

The annular flat surface formed on the side of the sleeve in close contact with the upper end surface of the sleeve, the concave groove for inserting rubber packing, and the space for inserting the adhesive are also annularly formed. 2 (b) has the same function as that of the first embodiment, and FIG. 3 (a) has the same shape and function as FIG. 2 (a).

The shape of each component constituting the oil dynamic pressure bearing 9 or, in a sealing part, a chamfered shape to be applied to the upper end surface of the sleeve 2, a close contact flat portion to be in close contact with the upper end surface of the sleeve 2, and a rubber packing It is needless to say that the concave groove into which the groove is inserted is not limited to the above-described embodiments, and may be variously modified without departing from the gist thereof. You may do it.

In FIG. 1, there is a minute gap D between the outer peripheral chamfered portion of the substantially cylindrical thruster 5 and the outer peripheral chamfered portion of the sleeve 2 in the lower part of FIG. Of course, oil is disposed in the gap between the end face of the thruster 5 and the lower end face of the sleeve 2. Since the dynamic pressure groove of the pump-in is formed in the end face B of the thruster 5 in the figure, the oil is theoretically It is thought that it does not flow out of D.

Experimentally, the thruster 5 and the sleeve 2 were actually constructed without the seal ring 6 as shown in FIG. In the experiment, the sleeve 2 was rotating at a high speed, and when the oil on the outer periphery of the sleeve 2 was blown off by centrifugal force, air entered into this portion instead, and the oil film was cut off inside the sleeve 2 bearing, causing oil outflow and air When the inflow of oil continues and proceeds, the oil in the sleeve 2 bearing decreases extremely. According to this experiment, it was found that the oil outflow phenomenon was affected by the size of the chamfer applied to the outer periphery of the sleeve 2 and the thruster 5.

The outer periphery of the lower end surface of the sleeve 2 in FIG. 1 has a protruding portion protruding from the lower end surface toward the thruster 5, and the tip of the protruding portion is formed on a surface E formed in the outer peripheral direction of the thruster 5. The outer fitting of the seal ring 6 having a shape extended to the vicinity of the upper side prevents oil from flowing out of the gap D due to centrifugal force without being affected by the size of the chamfer applied to the sleeve 2 and the thruster 5. Was found to be effective.

If there is a small gap between the inner peripheral surface of the seal ring 6 fitted to the outer peripheral surface of the sleeve 2 and the outer peripheral surface of the sleeve 2, if oil flows out of the clearance by capillary action, 2. The oil in the bearing portion decreases, and the effect of preventing the oil from leaking out of the seal ring 6 is reduced. Therefore, in order to further ensure this effect, an annular concave groove is formed in the inner surface of the seal ring 6 in contact with the outer peripheral surface of the sleeve 2, and a rubber packing 8 having a shape matching the concave groove is inserted therein. It is possible to do. This makes it possible to enhance the adhesion between the outer peripheral surface of the sleeve 2 and the inner peripheral surface of the seal ring 6 when the outer ring is fitted as described above, so that the effect of preventing the oil from leaking out of the seal ring 6 can be further ensured.

As shown in FIG. 1, an outer peripheral portion of the seal ring 6 has a sharp projection 14, and oil adhering to this portion is blown outward by a centrifugal force in a circumferential direction, and a cylindrical stator is formed. 7, rises along the inner diameter surface, and tends to scatter outside the oil dynamic pressure bearing 9 from a gap F between the lower end surface of the rotor 4 and the upper end surface of the stator 7.

The oil splatter described above can be achieved by stopping the force of the oil moving upward on the inner diameter surface of the stator. Therefore, a concave counterbore surface G is formed on the inner diameter surface of the stator 7 at a position facing the seal ring projection 14. Can be solved by having The cross-sectional shape of the counterbore surface G is more preferably an inverted tapered shape that is divergent toward the lower side in the concave shape.

The shapes of the thruster 5, the shape of the stator 7 and the counterbore surface G, or the concave grooves for inserting the projections 14 and the packing 8 in the seal ring are not limited to the above embodiments. It goes without saying that various modifications can be made without departing from the gist of the invention.
For example, the counterbore surface G of the stator 7 is formed in a counterbore shape represented by the above-described reverse taper shape, or a concave groove for inserting the protrusion 14 and the packing 8 in the seal ring is formed.
Each of them may have a substantially convex shape or a substantially concave shape.

[0036]

As described above, in the oil seal mechanism of the present invention, the inexpensive and simple components such as the seal component and the seal ring are used for the oil seal without changing the basic structure of the oil dynamic pressure bearing. The four functions of preventing oil outflow and air intrusion from the mouth portion, preventing air from escaping to the outside of the oil dynamic pressure bearing, and retaining oil can be realized by simply mounting the pressure bearing. This can provide a motor and an oil dynamic pressure bearing that can maintain high performance for a long time.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the configuration of an oil dynamic pressure bearing using an oil seal mechanism according to the present invention.

FIG. 2 (a) is a plan view showing a first embodiment of a seal component according to the present invention. FIG. 2B is a side sectional view showing the first embodiment of the seal component according to the present invention.

FIG. 3 (a) is a plan view showing a second embodiment of the seal component according to the present invention. (b) It is a sectional side view showing a second embodiment of the seal component according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Shaft 2 ... Sleeve 3 ... Seal part 4 ... Rotor 5 ... Thruster 6 ... Seal ring 7 ... Stator 8 ... Packing 9 ... Oil dynamic pressure bearing DESCRIPTION OF SYMBOLS 10 ... Surround formation space 11 ... Adhesive filling space 12 ... Outer periphery of seal part 13 ... Inner diameter surface of seal part 14 ... Protrusion 15 ... Close contact flat part

Claims (10)

[Claims] 1. A rotary sleeve which has a substantially cylindrical outer peripheral portion at a center position of a thruster serving as a base on a stator side, is formed in a substantially cylindrical shape, and is externally fitted to the fixed shaft. In the oil dynamic pressure bearing structure composed of a substantially cylindrical rotor externally fitted and fixed to the sleeve, an annular seal component having a chamfer applied to at least the inner diameter side of the end face of the sleeve is attached to the end face of the sleeve. By doing so, a seal function for preventing oil from flowing out from a gap between the outer peripheral surface of the shaft and the chamfered portion of the sleeve inner diameter, and an oil reservoir portion is formed in a gap between the outer peripheral surface of the shaft and the chamfered portion of the sleeve inner diameter. And sealing parts. 2. The seal component has an annular contact flat portion in contact with the sleeve end surface near the outermost periphery of the chamfer, and further has the sleeve end surface and the seal component on the outer peripheral side from the contact flat portion. 2. The seal component according to claim 1, further comprising a space for inserting an adhesive for tightly contacting a gap with the sealing member. 3. The seal component has an annular substantially concave groove on a surface in contact with the sleeve end surface, and an annular elastic material is inserted into the groove portion to insert the elastic member into the sleeve end surface. 3. The sealing part according to claim 1, wherein an oil sealing effect is provided by pressing the material insertion side. 4. The seal component has a shape in which a part of an arc of an outer peripheral portion thereof is cut out, and a part of an outer periphery of the seal component is fixed by being press-fitted into the inner diameter surface of the rotor. The cutout outer peripheral portion of the seal component has a partial gap with the rotor inner diameter surface, the excess of the adhesive overflows from the gap, and the excess adhesive pool on the upper and lower end surfaces. The seal component according to claim 1, wherein: 5. The seal component according to claim 1, wherein, instead of said chamfer, a substantially oil-shaped oil reservoir having an oil sealing effect is annularly formed on a surface which comes into contact with the outer peripheral surface of said shaft. The sealing component according to claim 3. 6. The seal component has an annular substantially convex portion on a surface that comes into contact with the sleeve end surface, and further, on the outer peripheral side from the substantially convex portion, the sleeve end surface and the seal component are separated from each other. 6. The sealing part according to claim 3, wherein a space for inserting an adhesive for tightly closing the gap is secured. 7. An oil seal mechanism using the seal component according to claim 1. 8. An oil dynamic pressure bearing structure formed of a fixed thruster and a rotary sleeve, both of which are formed in a substantially cylindrical shape, and which are externally fitted to the shaft, wherein an outer peripheral end face of the rotary sleeve is provided. When the seal ring is externally fitted, and when the seal ring is externally fitted to the outer peripheral end surface of the rotary sleeve, the seal ring has a shape protruding closer to the thruster than the sleeve end surface. A seal ring characterized by preventing oil scattering and outflow from a sliding portion gap portion between the fixed thruster outer chamfered portion and the rotary sleeve outer chamfered portion by centrifugal force, and the rotary sleeve and the rotary sleeve. An oil seal mechanism including a fixed thruster and the seal ring. 9. An inner diameter surface of the seal ring has an annular substantially concave groove near an end surface of the rotary sleeve, and an annular elastic material is inserted into the groove portion. 9. The seal ring according to claim 8, wherein an oil sealing effect is provided by pressing the outer ring against the outer peripheral surface of the rotary sleeve. 10. An outer peripheral portion of the seal ring has an annular substantially convex portion, and an inner surface of the substantially cylindrical stator, which is located on the outer periphery of the seal ring, has an annular substantially convex shape. The concave portion is arranged at a height opposite to the substantially convex portion of the seal ring and wider than the substantially convex portion, and the centrifugal force generated by rotation of the rotary sleeve causes the substantially convex portion to move away from the substantially convex portion. By receiving the oil scattered in the circumferential direction of the seal ring at the substantially concave shape portion, it is possible to prevent oil splattering outside the oil dynamic pressure bearing structure,
An oil seal mechanism comprising the seal ring according to claim 8 and a stator.