JP4156686B2 - Bearing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bearing device including a dynamic pressure bearing that uses the dynamic pressure of a fluid.
[0002]
[Prior art]
Conventionally, as shown in FIG. 3, this type of bearing device includes a shaft member 53 having a tip 52 having a conical outer peripheral surface 51, and a conical shape facing the outer peripheral surface 51 of the shaft member 53. A bearing member 56 having an inner peripheral surface 55, and a plurality of dynamic pressure grooves 57, 57... Bent in a V shape on the outer peripheral surface 51 of the shaft member 53 are formed in a row in the circumferential direction. Some have In the dynamic pressure bearing 59, when the shaft member 53 rotates in the direction of the arrow 58, the dynamic pressure groove 57 pumps the lubricating fluid toward the apex 57A of the dynamic pressure groove 57 to generate dynamic pressure. With this dynamic pressure, the shaft member 53 is rotatably supported with respect to the bearing member 56.
[0003]
[Problems to be solved by the invention]
However, in the conventional bearing device, since the shaft member 53 of the hydrodynamic bearing 59 has a conical shape at the time of starting rotation, the shaft member 53 easily enters the inner peripheral surface 55 of the bearing member 56 and at the time of startup. Since the rotation speed is slow, dynamic pressure is not sufficiently generated, so that there is a problem that the friction torque at the time of starting rotation tends to be large and the starting is likely to be difficult.
[0004]
Accordingly, an object of the present invention is to provide a bearing device in which a dynamic pressure bearing can be easily started.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 includes a shaft member and a bearing member facing the shaft member,
The shaft member and the bearing member each have a bearing surface,
The bearing surface of the shaft member and the bearing surface of the bearing member are opposed to each other,
The bearing surface of the bearing member is linear in a cross section of the bearing member by a surface including a central axis,
A bearing device having a dynamic pressure bearing in which a groove for generating dynamic pressure is formed on a bearing surface of the shaft member,
The groove for generating dynamic pressure is an inclined dynamic pressure generating groove,
A bearing surface of the shaft member in which the inclined dynamic pressure generating groove is formed,
A plurality of dynamic pressure groove existing portions in which the inclined dynamic pressure generating grooves and the hill portions adjacent to the inclined dynamic pressure generating grooves are alternately present in the circumferential direction;
Is extending surface from the lands with no respect to the dynamic pressure grooves presence section have circumferentially extending with adjacent inclined direction of extension of the inclined dynamic pressure generating grooves exist hydrodynamic groove A dynamic pressure groove nonexistent part,
Fluid supply support means for supplying fluid between the shaft member and the bearing member and supporting the shaft member relative to the bearing member so as to be relatively rotatable by static pressure;
The fluid supply support means includes
The fluid is formed in a bearing surface portion of the bearing member opposite the upper kidou grooves present unit has a supply hole for supplying to the dynamic pressure grooves present section,
The axially opposite sides of the gap between the shaft member and the bearing member open circumferentially adjacent to the non-existing portion of the dynamic pressure groove when the shaft member and the bearing member rotate relative to each other. .
[0006]
In the first aspect of the invention, the fluid supply support means supplies the fluid between the shaft member and the bearing member to generate a static pressure, and supports the shaft member relative to the bearing member so as to be rotatable relative to the bearing member. It becomes easy to start the hydrodynamic bearing.
[0007]
Moreover, invention of Claim 2 is a bearing apparatus of Claim 1,
The supply hole is
That it is formed in one place in the axial direction of the bearing surface facing the upper kidou grooves present section are characterized.
[0008]
Further, the invention of claim 3, the bearing apparatus according to claim 1 or 2, the supply hole is characterized in that at a equal intervals in the circumferential direction are formed in plural in the axial symmetry.
[0009]
Further, characterized in that the invention of claim 4, the bearing device according to any one of claims 1 to 3, in which the outer circumferential surface and the inner circumferential surface of the bearing member of the shaft member in a circular cone shape It is said.
[0010]
Invention of claim 4, with at static pressure is generated between the outer peripheral surface and the inner circumferential surface of the circular cone shape of the upper Kien cone shape, since supporting the shaft member, the bearing member and the shaft member Even if they are conical, they do not interfere with activation by engaging in a wedge shape.
[0011]
The invention of claim 5 is the bearing device according to any one of claims 1 to 3 ,
The fluid supply support means supplies fluid between the shaft member and the bearing member when the dynamic pressure bearing is started.
[0012]
According to the invention of claim 5, the fluid supply support means supplies a fluid between the shaft member and the bearing member when the dynamic pressure bearing is started to generate a static pressure so that the shaft member is supported with respect to the bearing member. Therefore, the dynamic pressure bearing can be easily started. At the time of steady rotation at a high rotation speed, sufficient dynamic pressure is generated, so that the fluid supply means stops supplying fluid. Thus, energy is saved.
[0013]
The invention according to claim 6 is the bearing device according to any one of claims 1 to 3 , wherein the fluid supply support means has a rotational speed of a predetermined value or less when the dynamic pressure bearing is started and stopped. In this case, fluid is supplied between the shaft member and the bearing member.
[0014]
According to the sixth aspect of the present invention, the fluid supply support means provides fluid between the shaft member and the bearing member when starting and stopping when the rotational speed of the hydrodynamic bearing is less than a predetermined value and the supporting force due to dynamic pressure is insufficient. To generate a static pressure to compensate for a lack of support force of the hydrodynamic bearing and to support the shaft member so as to be relatively rotatable with respect to the bearing member. Therefore, the dynamic pressure bearing can be started easily and promptly, and the reduction of the supporting force at the time of stopping can be compensated to prevent the rotating shaft member and the bearing member from contacting and being damaged. At the time of steady rotation at a high rotation speed, sufficient dynamic pressure is generated, so that the fluid supply means stops supplying fluid. Thus, energy is saved.
[0015]
According to a seventh aspect of the present invention, in the bearing device according to any one of the first to third aspects, the fluid supply support means changes a fluid supply amount in accordance with a rotational speed of the dynamic pressure bearing. It is characterized by.
[0016]
In the invention of claim 7 , since the fluid supply support means changes the fluid supply amount according to the rotational speed of the hydrodynamic bearing, the fluid supply amount is increased when the rotational speed is low and the dynamic pressure support force is small. While the static pressure is increased to supplement the support force, when the rotational speed is high and the dynamic pressure support force is large, the fluid supply amount is decreased to prevent fluctuations in the support force. Therefore, it is possible to stabilize the supporting force and reduce the fluid consumption.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
[0018]
FIG. 1 shows an embodiment of a bearing device according to the present invention. The bearing device of this embodiment includes a shaft member 1 and a bearing member 2. The shaft member 1 includes a shaft 3 and a tapered cylindrical portion 5. The tapered cylindrical portion 5 has a tapered substantially conical outer peripheral surface 5a. A plurality of inclined dynamic pressure generating grooves 9, 9... Arranged in the circumferential direction are formed on the outer peripheral surface 5a.
[0019]
On the other hand, the bearing member 2 has a substantially cylindrical shape, and has a substantially conical shape facing the tapered through hole 7 penetrating in the axial direction and the outer peripheral surface 5a of the tapered cylindrical portion 5 of the shaft member 1 with a predetermined gap therebetween. The inner peripheral surface 6 is provided. The inner peripheral surface 6 of the bearing member 2 and the tapered cylindrical portion 5 of the shaft member 1 constitute a hydrodynamic bearing 4. The bearing member 2 communicates with the axial through hole 7 and has a gas supply hole 8 penetrating in the radial direction at the center in the axial direction. A plurality of the gas supply holes 8 are formed axially symmetrically at substantially equal intervals in the circumferential direction, and are connected to the gas introduction pipe 12. The gas introduction pipe 12 is provided with a flow rate adjusting valve 13, and the amount of gas supplied from the gas introduction pipe 12 to the gas supply hole 8 can be adjusted by adjusting the opening of the valve 13. .
[0020]
Further, in this bearing device, a rotational speed sensor 10 that detects the rotational speed of the shaft 3 is arranged to face the shaft 3 of the shaft member 1. The rotational speed sensor 10 may be constituted by, for example, a magnetic sensor that detects a magnetic field that varies with the rotation of the shaft 3. The rotation speed sensor 10 is connected to a microcomputer 15, and the microcomputer 15 receives a signal indicating the rotation speed from the rotation speed sensor 10, and according to the rotation speed of the shaft 3, Adjust the opening.
[0021]
According to the bearing device having the above-described configuration, when the shaft member 1 rotates with respect to the bearing member 2, the plurality of inclined dynamic pressure generating grooves 9 formed on the outer peripheral surface 5 a of the shaft member 1 have the substantially conical shape of the bearing member 2. Dynamic pressure is generated in the gas between the inner peripheral surface 6 and the substantially conical outer peripheral surface 5 a of the shaft member 1 to support the shaft member 1 in the radial direction and the axial direction with respect to the bearing member 2.
[0022]
At the same time, the rotational speed sensor 10 detects the rotational speed of the shaft 3 of the shaft member 1 and sends a rotational speed signal to the microcomputer 15. The microcomputer 15 adjusts the opening degree of the valve 13 in accordance with the rotational speed represented by the rotational speed signal.
[0023]
An example of the control operation of the opening degree of the valve 13 by the microcomputer 15 is shown in FIG. In FIG. 2A, the change in the rotational speed N from the start time t = 0 to the stop time t = T is indicated by a solid line, and the change in the valve opening is indicated by a broken line. In the example of the valve opening degree control operation shown in FIG. 2A, the microcomputer 15 opens the valve 13 at a predetermined opening degree during the period from t = 0 when the rotation speed N = 0 to the rotation speed N = 500 rpm. Only when the rotation speed exceeds 500 rpm, the valve 13 is closed. When the rotational speed reaches the peak and then decreases to 500 rpm, the microcomputer 15 opens the valve 13 again by a predetermined opening degree until the rotational speed becomes zero until t = T. The valve 13 is kept at a predetermined opening.
[0024]
As described above, in the control example of FIG. 2A, when starting and stopping, when the rotational speed N of the shaft member 1 is low and the generated dynamic pressure is small, the valve 13 is opened and the gas supply hole 8 is opened. Gas is supplied between the inner peripheral surface 6 of the bearing member 2 and the outer peripheral surface 5 of the shaft member 1 to generate a static pressure. Therefore, the shaft member 1 can be reliably supported with respect to the bearing member 2 so as to be relatively rotatable while compensating for the lack of support force due to the dynamic pressure with the static pressure. Therefore, the friction torque at the time of starting rotation can be kept small, and the shaft member 1 can be prevented from being wedged into the bearing member 2 and can be started smoothly. Further, contact and damage between the shaft member 1 and the bearing member 2 immediately before stopping can be prevented. Further, when the rotational speed N exceeds 500 rpm, the gas supply from the valve 13 can be stopped to save the gas supply amount. In addition, energy for gas supply can be saved.
[0025]
Next, FIG. 2B shows another example of the valve opening degree control operation by the microcomputer 15. This operation example is common to the control example of FIG. 2A in that the valve 13 is opened in the period from the rotational speed N = 0 to N = 500 rpm, but the opening degree of the valve 13 is set to the rotational speed N. The point of inverse proportion is different from the control example of FIG.
[0026]
In this way, the valve opening is decreased according to the increase in the rotational speed N, while the valve opening is increased according to the decrease in the rotational speed N. This can further suppress the stabilization of the support force and reduce the gas consumption. In the above-described embodiment, the inclined dynamic pressure generating groove 9 is formed on the outer peripheral surface 5 a of the tapered cylindrical portion 5 of the shaft member 1 . Moreover, in the said embodiment, although the outer peripheral surface 5a of the shaft member 1 and the inner peripheral surface 6 of the bearing member 2 were made into the conical surface, a cylindrical surface may be sufficient. Further, in the dynamic pressure bearing of the bearing device of the present invention, the shaft member and the bearing member may constitute a thrust bearing. Further, in the above embodiment, the static pressure is generated at the time of starting and stopping the rotation of the dynamic pressure bearing 4, but the static pressure is reduced during a period when the rotational speed is decreased and the dynamic pressure is insufficient except at the time of starting and stopping. May be generated to stabilize the supporting force.
[0027]
【The invention's effect】
As is clear from the above, the invention of claim 1 is a bearing device having a dynamic pressure bearing, wherein the dynamic pressure generating groove is an inclined dynamic pressure generating groove, and the inclined dynamic pressure generating groove is formed. The bearing surface has a dynamic pressure groove existing portion in which a plurality of inclined dynamic pressure generating grooves and hill portions adjacent to the inclined dynamic pressure generating grooves are alternately present in the circumferential direction, and the dynamic pressure groove existing portion inclined not extend in the circumferential direction with adjacent inclined extending direction of the dynamic pressure generating grooves with no dynamic pressure generating groove and a dynamic pressure grooves absence portion is extending surface from the lands Fluid supply support means for supplying fluid between the shaft member and the bearing member and supporting the shaft member with respect to the bearing member so as to be relatively rotatable by static pressure, the fluid supply support means comprising: facing the upper kidou pressure groove exists portion the fluid is formed in a portion of the bearing surface of the bearing member It has kidou grooves supply holes for supplying the missing portion, the axial direction on both sides there non above dynamic pressure grooves of the gap between the shaft member and the bearing member during relative rotation between the shaft member and the bearing member it opens circumferentially adjacent section.
[0028]
In the first aspect of the present invention, the fluid supply support means supplies fluid between the shaft member and the bearing member to support the shaft member so as to be relatively rotatable with respect to the bearing member. It becomes easy to do.
[0029]
The invention of claim 4 is the bearing device according to any one of claims 1 to 3, in static pressure caused between the outer surface and the inner circumferential surface of the circular cone shape of a circular cone shape Therefore, even if the outer peripheral surface of the shaft member and the inner peripheral surface of the bearing member have a conical shape, they do not interfere with activation by being engaged in a wedge shape.
[0030]
In the invention of claim 5 , since the fluid supply support means supplies the fluid between the shaft member and the bearing member when the dynamic pressure bearing is started, the dynamic pressure bearing can be started easily. And at the time of steady rotation with a high rotational speed, supply of a fluid can be stopped and energy can be saved.
[0031]
The invention of claim 6, the fluid supply supporting means, when the number of rotation during starting and stopping of the dynamic pressure bearing is less than the predetermined value, by supplying a fluid between the shaft member and the bearing member The shaft member is supported so as to be rotatable relative to the bearing member. Accordingly, in the invention of claim 6 , the static pressure is generated by supplying the fluid between the shaft member and the bearing member by the fluid supply supporting means at the time of starting and stopping when the supporting force due to the dynamic pressure is insufficient. Make up for the lack of support of hydrodynamic bearings. Therefore, the dynamic pressure bearing can be started easily and promptly, and the reduction of the supporting force at the time of stopping can be compensated to prevent the rotating shaft member and the bearing member from contacting and being damaged. In addition, at the time of steady rotation at a high rotation speed, the supply of fluid can be stopped to save energy.
[0032]
In the invention of claim 7 , since the fluid supply support means changes the fluid supply amount according to the rotational speed of the hydrodynamic bearing, the fluid supply amount is increased when the rotational speed is low and the dynamic pressure support force is small. While the support force is supplemented by static pressure, when the rotational speed is high and the dynamic pressure support force is large, the fluid supply amount is reduced to reduce the static pressure and suppress fluctuations in the support force. Therefore, it is possible to stabilize the supporting force and reduce the fluid consumption.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of a bearing device according to the present invention.
FIG. 2A is a diagram for explaining an example of the valve control operation according to the above embodiment, and FIG. 2B is a diagram for explaining another example of the valve control operation.
FIG. 3 is a view showing a conventional bearing device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Shaft member, 2 ... Bearing member, 3 ... Shaft, 4 ... Dynamic pressure bearing, 5 ... Tapered cylindrical part,
5a ... outer peripheral surface, 6 ... inner peripheral surface, 7 ... through hole, 8 ... gas supply hole,
9 ... Dynamic pressure generating groove, 10 ... Rotational speed sensor, 12 ... Gas introduction pipe,
13 ... Flow control valve, 15 ... Microcomputer.

Claims (7)

A shaft member and a bearing member facing the shaft member;
The shaft member and the bearing member each have a bearing surface,
The bearing surface of the shaft member and the bearing surface of the bearing member are opposed to each other,
The bearing surface of the bearing member is linear in a cross section of the bearing member by a surface including a central axis,
A bearing device having a dynamic pressure bearing in which a groove for generating dynamic pressure is formed on a bearing surface of the shaft member,
The groove for generating dynamic pressure is an inclined dynamic pressure generating groove,
A bearing surface of the shaft member in which the inclined dynamic pressure generating groove is formed,
A plurality of dynamic pressure groove existing portions in which the inclined dynamic pressure generating grooves and the hill portions adjacent to the inclined dynamic pressure generating grooves are alternately present in the circumferential direction;
Is extending surface from the lands with no respect to the dynamic pressure grooves presence section have circumferentially extending with adjacent inclined direction of extension of the inclined dynamic pressure generating grooves exist hydrodynamic groove A dynamic pressure groove nonexistent part,
Fluid supply support means for supplying fluid between the shaft member and the bearing member and supporting the shaft member relative to the bearing member so as to be relatively rotatable by static pressure;
The fluid supply support means includes
The fluid is formed in a bearing surface portion of the bearing member opposite the upper kidou grooves present unit has a supply hole for supplying to the dynamic pressure grooves present section,
The axially opposite sides of the gap between the shaft member and the bearing member are opened circumferentially adjacent to the non-existing portion of the dynamic pressure groove when the shaft member and the bearing member are rotated relative to each other. Bearing device. The bearing device according to claim 1,
The supply hole is
Bearing apparatus characterized by being formed in one place in the axial direction of the bearing surface facing the upper kidou grooves present section. The bearing device according to claim 1 or 2,
The supply hole is
Bearing apparatus characterized by being formed in plural axisymmetrically spaced equal intervals in the circumferential direction. The bearing device according to any one of claims 1 to 3 ,
Bearing device being characterized in that the outer circumferential surface and the inner circumferential surface of the bearing member of the shaft member in a circular cone shape. The bearing device according to any one of claims 1 to 3 ,
The said fluid supply support means supplies a fluid between the said shaft member and a bearing member at the time of starting of the said dynamic pressure bearing, The bearing apparatus characterized by the above-mentioned. The bearing device according to any one of claims 1 to 3 ,
The fluid supply support means supplies fluid between the shaft member and the bearing member when the rotational speed is equal to or less than a predetermined value when the dynamic pressure bearing is started and stopped. . The bearing device according to any one of claims 1 to 3 ,
The bearing device according to claim 1, wherein the fluid supply support means changes a fluid supply amount in accordance with a rotational speed of the dynamic pressure bearing.

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