JPS6137853Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to the improvement of a thrust bearing device used in a high-precision rotating spindle. Specifically, the thrust bearing portion is formed by using both a sliding bearing and a hydrodynamic bearing. .

For example, as shown in FIG. 1, a hydrodynamic thrust bearing device that has been widely used in audio equipment, video equipment, etc. has a radial bearing portion 2a such as a sliding bearing or a hydrodynamic bearing on the inner peripheral surface of a support member 1a.
The support member 1a has a groove for generating dynamic pressure at its bottom, and a sphere 4 at its center whose apex contacts the end surface 31a of the shaft body 3a when the bearing is stopped or when the pressure is low.
a flat thrust member 5a for holding a;
In addition, the shaft 3a is supported by a thrust bearing portion constituted by the thrust member 5a and the end face 31a of the shaft 3a facing the shaft, and when the shaft 3a is at a steady rotational speed, the thrust The thrust load applied to the shaft body 3a is transferred to the sphere 4 by the dynamic pressure caused by the pressure increase of the lubricant present in the bearing part.
The load is applied only by the dynamic pressure, regardless of a.

In general, this type of bearing device requires high precision and low cost due to the nature of the equipment used, so it requires an extremely rational structure suitable for mass production. Since the two members of the bearing are made of metal, they tend to come into contact with each other and cause scratches.Therefore, there has been a strong demand for rationalization and simplification of the structure as well as measures to prevent the occurrence of scratches. On the other hand, at steady rotation speed, since the thrust load is received only by dynamic pressure as mentioned above, the torque tends to increase due to the viscous resistance of the grease as a lubricant, even if there is no contact. It was hot.

This invention compensates for the above-mentioned drawbacks of conventional products and provides a thrust bearing device that is scratch resistant, simple in structure, and inexpensive.

Next, a second thrust bearing device based on this invention was installed.
To explain the typical embodiments shown in FIGS. 1 is a supporting member, 2 is a radial bearing portion, 3 is a shaft body, 31 is an end face of the shaft body,
4 is a bearing member, 41 is an end face of the bearing member, 42 is a convex portion, 43 is a spigot portion, 44 is a rotation stopper, 5 is a thrust member, 51 is a thrust bearing surface, 6 is a dynamic pressure generating groove, 7 is a recessed portion, 71 is the bottom surface of the recess, 8 is a circulation hole, and 9 is an O-ring. In the embodiment, a gap is shown between the convex portion 42 and the mating surface 4 (other surface) for ease of understanding when explaining the details, but during steady rotation, they lightly touch each other. There is a relationship where

First, the first embodiment of this invention shown in FIG. 2 will be described. Two radial bearings 2, 2 similar to the conventional ones are provided on the inner circumferential surface of the support member 1. A thrust member 5 having a flat thrust bearing surface 51 is fixed to the bottom surface of the shaft member 1, and forms a thrust bearing portion together with the end surface 31 of the shaft body 3, and supports the shaft body 3 together with the radial bearing portion 2. However, unlike the conventional product shown in Fig. 1, the end face 31 of the shaft body 3 is made of hard plastic with a compressive strength of 500 kg/cm ² or more, and the shaft body 3 is supported at the center when the rotation is stopped or when the pressure is low. The shaft body 3 has a slight protrusion 42 on the surface that contacts the end surface 31, and has a detent with a spigot portion 43 and a protrusion 44 inserted into a stopper hole, and a flat portion in contact with the end surface 31 has a detent that is inserted into a stopper hole. An end surface 4 that is thin and opposite to the contact surface
A bearing member 4 having a dynamic pressure generating groove 6 is coupled to the thrust member 1 to form a thrust bearing portion together with the thrust receiving surface 51 of the thrust member 5.

In general, the thicker a plastic product is, the more likely it is that warp distortion occurs on the flat surface. Therefore, in the bearing member 4 of this invention, the thickness of the wall surface is set to the depth of the dynamic pressure generating groove 6 to ensure sufficient accuracy. of
It is thinly formed, less than 100 times the thickness, and this effect ensures the necessary accuracy as a hydrodynamic bearing.

Furthermore, since it is made of hard plastic (including composite materials filled with inorganic materials, solid lubricants, etc.) with a compressive strength of 500 kg/cm ² or more, Convex part 4
There is no risk of deformation or wear during use, and even if the bearing member 4 comes into contact with other metal members that make up the thrust bearing, it will not damage the end face of the other member or the groove that generates dynamic pressure. You can use it with confidence without damaging anything.

In addition, conventional products have a large number of parts such as holding the sphere 4a on the thrust member 5a, and the process is complicated, which tends to increase the cost, but in this invention, when molding the bearing member 4 made of plastic,
In addition to forming the outer periphery of the convex portion 42, the spigot portion 43, and the anti-rotation convex portion 44, the dynamic pressure generating groove 6 provided on the end face 41 can also be formed at the same time. The anti-rotation convex portion 44 makes it easy to ensure assembly accuracy, and by simplifying the structure and rationalizing the components as described above, the problems that tend to increase in conventional costs are solved, making assembly easy. Thus, it is possible to obtain an inexpensive thrust bearing device in which the thrust bearing portion is less likely to be damaged.

FIG. 3 shows a second embodiment of this invention, in which a recess 7 is provided in the center of the thrust receiving surface 51 of the thrust member 5, and the bearing member 4 is attached to the bottom surface 71 of the recess 7. There is.

In this embodiment, in addition to the same effect as in the first embodiment, the recess 7 serves as an oil reservoir for storing lubricant, and the lubricant does not flow out of the bearing, making assembly work easier. Furthermore, by connecting the bearing member 4 to the recessed portion of the metal thrust member 5, the bearing member 4 made of thin plastic is prevented from deflecting due to the load, and stable operation can be achieved.

FIG. 4 shows a third embodiment of this invention, in which a thrust member 5 and a bearing member 4 made of plastic are connected by a pilot part 43 formed in the center of the bearing member 4, and A thin lip-shaped seal portion 45 is integrally formed on the outer side of the dynamic pressure generation groove 6 of the bearing member 4,
The seal portion 45 is in contact with the counterbore surface 11 of the support member 1 to perform a sealing function.

Therefore, in this embodiment, it is possible to completely prevent the lubricant inside the bearing from leaking to the outside, and at the same time, due to the pressing force between the lip-shaped seal portion 45 and the support member 1, the bearing member 4 is strongly pressed against the thrust receiving surface 51 and has the functions of preventing rotation and fixing at the same time.

As described above, since the bearing member 4 of this embodiment is integrally formed to have both the function of sealing the spigot part and the function of preventing rotation, the structure is extremely simple and the cost reduction effect is large.

FIG. 5 shows a fourth embodiment of this invention, which has almost the same structure as the third embodiment described above.
By using an O-ring 9 instead of the lip-shaped sealing part, the same effect as in the third embodiment can be achieved. By using the O-ring, which is a special sealing member, the sealing function becomes more reliable and stable. It is possible to drive with ease.

FIG. 6 shows a fifth embodiment of this embodiment, in which the bearing member 4 is connected to the bottom surface 71 of the recess 7 provided in the thrust receiving surface 51 as in the second embodiment. A lubricant circulation hole 8 is provided that communicates from the apex of the convex portion 42 through the inside of the thrust member 5 to the thrust bearing portion so that the lubricant oil in the recessed portion 7 is constantly circulated and used. When the dynamic pressure of the lubricant increases above a certain pressure through the circulation hole 8, the high-pressure lubricant escapes through the lubricant 8 and returns to the original thrust bearing in the recess. Since the lubrication action is repeated, the pressure in the thrust bearing part always remains constant, and the flying height of the shaft body 3 also becomes constant, allowing stable operation.

As mentioned above, the thrust bearing device of this invention not only reduces the cost due to its simple structure, but also enables metal-to-metal contact by joining thin-walled bearing members made of plastic or plastic composite materials. Since it can be avoided, there will be no scratches on the mutual contact surfaces, and at the same time, there will be little wear and torque during rotation and stop, allowing for smooth starting and stopping. By generating dynamic pressure, the contact pressure due to the above-mentioned contact is reduced, and rotation can be performed with lower torque. That is, the thrust bearing functions as a contact and dynamic pressure bearing, and the torque is smaller than that of just one type of bearing support.

In addition, since the bearing member constituting the thrust bearing section is thin, it can be machined with high accuracy, and the rotatability of the thrust bearing section is improved. Furthermore, the embodiment shown in Fig. 6 has circulation holes that allow stable operation under constant pressure, so it has ideal performance and is expected to have an expanded range of applications. .

In the first embodiment of this invention, the bearing member 4 is coupled to the shaft body 3, but the bearing member 4 is not limited to this, and may be coupled to the thrust member 5.
In addition, this connection is not simply a spigot connection, but may also be performed by insert molding integrally with the shaft body 3 or the thrust member 5 during plastic injection molding. It is also possible to provide it only inside.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the main parts of a conventionally used thrust bearing device, Figures 2, 3, 4, and 5.
6 and 6 are sectional views of essential parts of an embodiment of the thrust bearing device according to this invention, respectively. In the figure, numeral 1 is a support member, 2 is a radial bearing, and 3
4 is a shaft body, 4 is a bearing member, 5 is a thrust member, 6 is a dynamic pressure generating groove, 7 is a recess, 8 is a circulation hole, and 9 is an O-ring.

Claims (1)

[Claims for Utility Model Registration] (1) Consisting of a radial bearing provided on the inner peripheral surface of a support member, a thrust bearing surface of a thrust member fixed to the support member, and an end surface of a shaft body. In the dynamic pressure thrust bearing device, the shaft body is supported by a thrust bearing part, and each of the bearing parts has a lubricant, either an end face of the shaft body or a thrust bearing surface of the thrust member. The side is made of thin wall made of plastic stick or plastic stick composite material, and the end face shape facing the other side is flat or curved close to flat, and moreover, the center is always in contact with the other facing side. A bearing member having a slight protrusion is coupled, and a dynamic pressure generating groove is provided on the end face of the bearing member and/or another face constituting the thrust bearing part together with the end face, and during steady rotation,
A dynamic pressure thrust bearing device characterized in that a thrust bearing portion is formed by both sliding and dynamic pressure. (2) The hydrodynamic thrust bearing device according to claim 1 of the utility model registration claim, wherein the plastic stick or plastic composite material is hard plastic stick with a compressive strength of 500 Kg/cm ² or more. (3) The hydrodynamic thrust bearing device according to either of claims 1 and 2 of the utility model registration claim, in which the bearing members are connected by a spigot connection. (4) A hydrodynamic thrust bearing having a rotation stopper between the bearing member and the end face of the shaft body, the thrust member, or the support member, as set forth in any of claims 1, 2, and 3 of the claims for utility model registration. Device. (5) The hydrodynamic thrust bearing device according to claim 4 of the utility model registration, in which the rotation stopper is formed by inserting a convex portion formed integrally with the bearing member into the end face of the shaft body or a stopper hole in the thrust member. (6) The hydrodynamic thrust bearing device according to claim 4 of the utility model registration, in which the detent is formed by pressing a lip having a sealing function that is integrally formed with the bearing member against the support member. (7) The hydrodynamic thrust bearing device according to claim 4 of the utility model registration, in which the rotation stopper is formed by pressing an O-ring between a bearing member and a support member. (8) In any of claims 1, 2, 3, 4, and 5 of the claims for utility model registration, a recess is provided in the thrust receiving surface, and a bearing member is coupled to the bottom of the recess. Hydrodynamic thrust bearing device. (9) In any one of claims 1, 2, 3, 4, 5, 6, 7, and 8 of the scope of utility model registration claims, the convexity of the bearing member A dynamic pressure thrust bearing device with a circulation hole that communicates from the apex of the thrust bearing section to the periphery of the thrust bearing section.