JPH0518489Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention relates to a hydrodynamic bearing device that supports a shaft using the dynamic pressure of a fluid.

<Prior Art> Conventionally, there is a hydrodynamic bearing device as shown in FIG. In this hydrodynamic bearing device, herringbone-shaped radial dynamic pressure generating grooves 5 and 6 are provided on the outer peripheral surface of the shaft 1, and the inner end surface 3a of the thrust receiver 3 press-fitted into one end of the shaft 1 is provided with grooves 5 and 6 for generating radial dynamic pressure as shown in FIG. A thrust dynamic pressure generating groove is provided which extends clockwise on the inside and counterclockwise on the outside in the radial direction from the shaft hole as shown in FIG. When the shaft 1 is inserted into the shaft hole 7 of the sleeve 2 having a substantially cylindrical shape as shown in FIG. , are arranged close to the outer peripheral surface of the shaft 1. Further, the inner end surface 3a of the thrust receiver 3 and the end surface 2a of the sleeve 2 facing the inner end surface 3a are parallel to and close to each other.

When the sleeve 2 rotates in the direction of the arrow x relative to the shaft 1 and the thrust receiver 3, the pump action of the radial dynamic pressure generating grooves 5 and 6 causes the outer peripheral surface of the shaft 1 and the inner peripheral surface of the sleeve 2 to Surfaces 7a and 7b
Fluid pressure (radial dynamic pressure) is generated between the two and the shaft 1 is supported in the radial direction by this radial dynamic pressure. In addition, due to the pumping action of the thrust dynamic pressure generating groove, the end surface 2a of the sleeve 2 and the thrust receiver 3
Fluid pressure (thrust dynamic pressure) between the inner end surface 3a of
is generated, and this thrust dynamic pressure supports the shaft 1 in the thrust direction.

<Problems to be solved by the invention> However, the conventional hydrodynamic bearing device described above has the following problems:
Due to the rotation of the sleeve 2 relative to the shaft 1, there are Since the shaft 1 is supported in the radial and thrust directions by the generated fluid pressure, the distance between the end surface 2a of the sleeve 2 and the inner end surface 3a of the thrust receiver 3 is different on the left and right sides in the figure (i.e. , inner end surface 3a
is not perpendicular to axis 1), the fluid pressure generated on the narrower side (for example, the right side) is greater than the fluid pressure generated on the wider side (for example, the left side), so the right end face The distance between the thrust receiver 2a and the inner end surface 3a tends to widen due to the difference in fluid pressure, and the thrust receiver 3 tries to correct the inclination of the inner end surface 3a. However, shaft 1 is thrust receiver 3
Because it is fixed by press fitting into the shaft hole 7, when the thrust receiver 3 tries to correct its inclination, the shaft 1
deviates from the center of Then, this time axis 1
The radial dynamic pressure on the outer peripheral surface becomes uneven,
As in the case of thrust dynamic pressure, in order to equalize this non-uniform radial dynamic pressure, an attempt is made to return the center position of the shaft 1 to a position concentric with the center of the shaft hole 7.
As a result, there is a problem that vibrations occur in the shaft 1 and the shaft 1 does not rotate smoothly.

In order to solve the above problem, if we try to make the distance between the end surface 2a of the sleeve 2 and the inner end surface 3a of the thrust receiver 3 the same everywhere (that is, make the end surface 2a and the inner end surface 3a parallel),
It is necessary that the angle between the inner end surface 3a of the thrust receiver 3 and the center of the shaft 1 and the angle between the end surface 2a of the sleeve 2 and the center of the shaft hole 7 be right angles. Therefore, when manufacturing the sleeve 2 and the thrust receiver 3, and when press-fitting the shaft 1 into the thrust receiver 3, a highly accurate technique is required, resulting in a problem of high processing costs.

Therefore, the purpose of this invention is to create a structure in which the thrust receiver can tilt with respect to the axis, so that the precision required for machining the thrust receiver and sleeve is low, and it is easy to assemble. It is an object of the present invention to provide a hydrodynamic bearing device that has low processing cost, is inexpensive, and provides smooth rotation.

<Means for Solving the Problems> In order to achieve the above object, this invention provides a dynamic pressure generating section on at least one of the opposing end surfaces of the sleeve and the thrust receiver through which the same shaft passes through, and A dynamic pressure type bearing that supports the shaft in the thrust direction by generating dynamic pressure in the fluid between the sleeve-side end surface of the thrust receiver and the end surface of the sleeve opposite to that end surface by rotation relative to the thrust receiver. In the device, the shaft hole of the thrust receiver that is penetrated by the shaft has an inner diameter larger than the outer diameter of the shaft so that the thrust receiver can tilt with respect to the shaft, and a shaft hole that is larger than the outer diameter of the thrust receiver. The present invention is characterized in that it includes a holding member that contacts the thrust receiver with a contact surface having a small outer diameter to support the thrust receiver in the axial direction, and prevents the thrust receiver from rotating with respect to the axis.

<Operation> When the sleeve is rotated relative to the axis,
Since the thrust receiver, which is supported in the axial direction in contact with the contact surface of the holding member, is prevented from rotating with respect to the axis by the holding member, the sleeve is also rotated relative to the thrust receiving member. . Then, due to the pumping action of the dynamic pressure generating section provided on at least one of the sleeve-side end surface of the thrust receiver and the end surface of the sleeve opposite to that end surface, the sleeve-side end surface of the thrust receiver and the end surface of the sleeve opposite to that end surface are Fluid pressure (thrust dynamic pressure) is generated in the fluid between the two, and the shaft is supported in the thrust direction by this thrust dynamic pressure.

At this time, the inner diameter of the shaft hole of the thrust receiver is larger than the outer diameter of the shaft, and the outer diameter of the contact surface of the presser member with the thrust receiver is smaller than the outer diameter of this thrust receiver, so the thrust receiver is Can be easily tilted about the axis. Therefore, if there is variation in the thrust dynamic pressure due to non-uniform spacing between the two end faces, the sleeve of the thrust receiver can be The inclination of the side end surfaces is automatically corrected to maintain an even and stable thrust dynamic pressure.

Therefore, it is possible to make the attachment accuracy of the thrust receiver to the shaft rough, and to make the relative rotation of the sleeve to the shaft smooth.

<Example> This invention will be explained in detail below with reference to the illustrated example.

In FIG. 1, 11 is a shaft passing through the sleeve 12, 13 is a thrust receiver having a shaft hole 17 in the center through which the shaft 11 passes, and 14 is a holding member press-fitted onto one end of the shaft 11.

The shaft 11 of the sleeve 12 is attached to the outer peripheral surface of the shaft 11.
A herringbone-shaped radial dynamic pressure generating groove 1 whose tip is oriented in the same direction as the relative rotational direction to the
5 and 16 are provided. The sleeve 12 has a shaft hole 18 through which the shaft 11 passes, and an inner peripheral surface 18 of the shaft hole 18 that faces the radial dynamic pressure generating grooves 15 and 16.
a and 18b are arranged close to the outer peripheral surface of the shaft 11.

As shown in FIG. 2, the end surface 19 of the thrust receiver 13 is provided with a thrust dynamic pressure generating groove 20 extending clockwise on the inside and counterclockwise on the outside in the radial direction from the shaft hole 17. On the other hand, the other end surface 2
A pawl 22 extending axially outward is provided on the outer periphery of 1. Further, the inner diameter of the shaft hole 17 is set larger than the outer diameter of the shaft 11, so that the thrust receiver 13 can be tilted with respect to the shaft 11.

A hole into which the shaft 11 is press-fitted is provided in the center of the holding member 14, and a groove 23 in which the pawl 22 of the thrust receiver 13 is accommodated is provided in the outer peripheral surface of the hole. Further, the outer diameter of the contact surface of the presser member 14 with the thrust receiver 13 is set smaller than the outer diameter of the thrust receiver 13.

The shaft 11, sleeve 12, thrust receiver 13
The presser member 14 is press-fitted and fixed to one end of the shaft 11 to be assembled together in the following manner. Next, insert this shaft 11 into the shaft hole 17 of the thrust receiver 13, insert the pawl 22 into the groove 23 of the holding member 14, and insert the thrust receiving member 13 and the holding member 1.
4. Therefore, the shaft 11 and the holding member 1
4 and the thrust receiver 13 can be stopped or rotated together. Next, the shaft 11 and the thrust receiver 13 are inserted into the shaft hole 18 of the sleeve, and the thrust dynamic pressure generation groove 2 of the thrust receiver 13 is inserted into the shaft hole 18 of the sleeve.
0 on one end surface 24 of the sleeve 12.
to face. At that time, the shaft hole 1 of the sleeve 12
The inner peripheral surfaces 18a and 18b of the shaft 11 face the radial dynamic pressure generating grooves 15 and 16 of the shaft 11.

In the hydrodynamic bearing device, the sleeve 12 is connected to the shaft 11.
When the sleeve 12 rotates in the direction of arrow X relative to . Then, the end face 19 of the thrust receiver 13 and the sleeve 1
A fluid flow is generated between the end surface 24 of the thrust receiver 13 and the end surface 24 of the sleeve 12 due to the pump action of the thrust dynamic pressure generating groove 20.
Thrust dynamic pressure is generated in the fluid between the thrust dynamic pressure and the apex 20a of the thrust dynamic pressure generation groove 20, and the shaft 11 is supported in the thrust direction by this thrust dynamic pressure. Furthermore, when the sleeve 12 rotates in the direction of arrow X, a fluid flow is generated toward the center of the herringbone shape due to the pump action of the radial dynamic pressure generating grooves 15 and 16, and the inner peripheral surface of the shaft hole 18 of the sleeve 12
Radial dynamic pressure is generated in the fluid between 8a, 18b and the outer peripheral surface of the shaft 11, and the shaft 11 is supported in the radial direction by this radial dynamic pressure having a maximum at the center of the herringbone shape.

At that time, for example, the end surface 24 of the sleeve 12 is tilted downward on the left side in the figure with respect to the shaft hole 18,
When the thrust dynamic pressure on the left side with respect to the shaft 11 is large, the gap between the left end face 24 and the end face 19 increases due to the difference in thrust dynamic pressure, and the thrust dynamic pressure on the left side decreases, automatically increasing the thrust dynamic pressure. The pressure becomes even. In this case, the shaft hole 1 in the thrust receiver 13
The inner diameter of the shaft 11 is larger than the outer diameter of the holding member 1.
Since the outer diameter of the contact surface with the thrust receiver 13 at 4 is set smaller than the outer diameter of the thrust receiver 13, the thrust receiver 13 can easily tilt with respect to the shaft 11. Therefore, the center position of the shaft 11 will not deviate from its original position. That is, by utilizing the non-uniformity of the thrust dynamic pressure, the inclination of the thrust receiver 13 with respect to the axis 11 is automatically corrected until the thrust dynamic pressure becomes uniform and stable.

Note that the inner end surface of the presser member 14 is slightly inclined with respect to the shaft 11 so that the pawl 22 is caught in the groove 23, so the perpendicularity between the presser member 14 and the shaft 11 when press-fitting the shaft 11 into the presser member 14 is may have low accuracy.

In this way, even if the accuracy of the mounting angle of the thrust receiver 13 with respect to the shaft 11 is rough, the relative rotation of the sleeve 12 with respect to the shaft 11 can be made smooth, and the end surface 24 of the sleeve 12 can be made smooth.
The precision of the perpendicularity between the shaft hole 18 and the shaft hole 18 and the perpendicularity between the end face 19 of the thrust receiver 13 and the shaft 11 can be reduced, and assembly can be facilitated to reduce processing costs.

FIG. 3 shows that the inner circumferential end of a substantially disk-shaped presser member 62 having a hole in the center is fitted into a groove 65 provided at one end of the outer circumferential surface of the shaft 11, and is further fixed. is engaged with the thrust receiver 61 with the pin 63,
The shaft 11, the holding member 62, the pin 63, and the thrust receiver 61 are rotated or stopped together.

FIG. 4 shows that on the outer end surface 74 of the thrust receiver 71,
A perforated member 73 having a hole in the center through which the shaft 11 passes and a hole 75 on the end face is pasted. Also, the end face 7
A presser member 72 having a pin 77 provided at 6 is press-fitted into one end of the shaft 11. Then, the pin 7 of the presser member 72
7 into the hole 75 of the perforated member 73, and
1. The holding member 72, the perforated member 73, and the thrust receiver 71 are rotated or stopped together.

The embodiment shown in FIGS. 3 and 4 above is as follows:
Similarly to the embodiment shown in FIG. ing. Furthermore, the outer diameters of the holding members 62 and 72 are made smaller than the outer diameters of the thrust receivers 61 and 71. Therefore, in order to make the thrust dynamic pressure uniform and stable, the inclination of the thrust receivers 61 and 71 with respect to the shaft 11 is adjusted without causing the center position of the shaft 11 to oscillate with respect to the center of the shaft hole 18 of the sleeve 12. Easily and automatically corrected.

<Effects of the invention> As is clear from the above, the hydrodynamic bearing device of this invention has a thrust receiver that has an end face opposite to one end face of the sleeve and generates dynamic pressure between it and the one end face of the sleeve. , the inner diameter of the shaft hole of the thrust receiver is made larger than the outer diameter of the shaft so that it can tilt with respect to the shaft, and the thrust receiver is mounted on the shaft with a contact surface having an outer diameter smaller than the outer diameter of the thrust receiver. Since it is equipped with a holding member that supports the thrust receiver in the direction and prevents it from rotating with respect to the shaft, the center position of the shaft can be oscillated relative to the center of the shaft hole of the sleeve so that the thrust dynamic pressure is uniform and stable. The inclination of the thrust receiver with respect to the axis can be automatically corrected without causing any vibration, and therefore smooth rotation can be obtained without vibration or the like.

In addition, the hydrodynamic bearing device of this invention lowers the accuracy of the perpendicularity of the end face of the thrust receiver to the axis and simplifies the structure of the holding member, as described above, so that machining costs can be reduced, and
It can be easily assembled and manufactured at low cost.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of one embodiment of the hydrodynamic bearing device of this invention, Fig. 2 is a plan view of the thrust dynamic pressure generating groove in Fig. 1, and Figs. 3 and 4 are other embodiments. FIG. 5 is a vertical cross-sectional view of a conventional hydrodynamic bearing device. 11...shaft, 12...sleeve, 13, 61,
71... Thrust receiver, 14, 62, 72... Holding member, 15, 16... Radial dynamic pressure generation groove,
17...Shaft hole, 20...Groove for generating thrust dynamic pressure.

Claims (1)

[Claims for Utility Model Registration] A dynamic pressure generating section is provided on at least one of the opposing end surfaces of the sleeve and the thrust receiver through which the same shaft passes, and the sleeve of the thrust receiver is rotated relative to the thrust receiver. In a hydrodynamic bearing device that supports a shaft in the thrust direction by generating dynamic pressure in the fluid between a side end surface and an end surface of a sleeve opposite to the end surface, the thrust receiver is penetrated by the shaft. The shaft hole has an inner diameter larger than the outer diameter of the shaft so that the thrust receiver can tilt with respect to the shaft, and a contact surface that connects the thrust receiver with an outer diameter smaller than the outer diameter of the thrust receiver. A hydrodynamic bearing device comprising a presser member that contacts the thrust receiver in the axial direction and prevents the thrust receiver from rotating with respect to the shaft.