JPH0416655B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel plain bearing with thixotropic lubrication function.

In general, sliding bearings such as plastic bearings and non-lubricated bearings exhibit excellent sliding properties without the use of oil, in other words, when dry, but when used in combination with a lubricant such as oil, the sliding properties are significantly improved. It is known to exhibit excellent friction and wear characteristics.

Therefore, it is often done to apply grease by forming grooves or depressions on the sliding surface, and although this is extremely effective for preventing leakage,
The following problems cannot be ignored.

(a) Grease has a very high viscosity, so there is a limit to its ability to improve frictional properties, and the coefficient of friction does not decrease as much as when low-viscosity oil is used. Therefore, there is a limit to torque reduction.

(b) Due to its high viscosity, grease is difficult to draw into sliding parts, and the improvement in wear characteristics is not as remarkable as when using a liquid lubricant such as oil. Therefore, the torque is unstable.

On the other hand, when a liquid lubricant such as oil is used, a low coefficient of friction and excellent wear resistance can be obtained, but since it is difficult to seal the liquid, there is a problem with the reliability of long-term lubrication life.

Furthermore, if the oil seal is used to seal the oil seal, the frictional resistance will increase significantly, and the purpose of using a liquid lubricant will be lost.

Furthermore, sliding bearings using thixotropic lubricants are known, but they reduce torque and
Torque instability can be resolved, but lubricant often flows out, which poses many practical problems.

By the way, this thixotropic lubricant is obtained by mixing a thixotropic agent such as ultrafine amorphous anhydrous silica or ultrafine clay into a liquid lubricant and stirring the mixture vigorously. The viscosity of the mixture increases and can be easily gelled. Due to the shearing of the sliding portion of the bearing, the gel-like liquid lubricant becomes a sol, which acts to reduce torque.

Thus, thixotropic lubricants
When used in a sliding bearing, when there is no rotational action, it solidifies in a gel state, but when there is rotational action, it changes to a sol state and becomes liquid, resulting in a decrease in torque, as described above. However, the inconvenience that the lubricant flows out from the end of the bearing along the rotating shaft cannot be avoided.

This invention has been made by focusing on the above points, and includes a pocket-shaped reservoir provided on at least one side edge of the sliding portion of the bearing, in which a portion of the lubricant having thixotropic properties is stored. To provide a sliding bearing which can be filled with the lubricating oil, thereby completely sealing the outflow of lubricating oil that has been turned into sol due to shearing of the bearing portion.

Another object of the present invention is to provide a sliding bearing in which a labyrinth seal is attached to the pocket-shaped reservoir to more reliably prevent leakage of lubricant within the reservoir.

A further object of the present invention is to provide a sliding bearing in which dynamic pressure generating grooves are provided on the outer periphery of the rotating shaft of the sliding portion of the bearing or on the inner periphery of the bearing to improve friction and wear resistance.

Examples of the present invention will be described below with reference to the drawings.

In each figure, 1 is a desired rotating shaft, 2 is a bearing member, 3 is a thixotropic lubricant filled in the sliding portion between the rotating shaft 1 and the bearing member 2, and 4 is the sliding portion of the bearing member 2. a pocket-shaped reservoir provided on at least one side of the lubricant 3;
is partially filled.

By the way, the bearing member 2 can be made of any material such as general metal materials, plastics, and ceramics, and is not limited to the configuration shown in the drawings. The present invention can also be applied to a rotating configuration. Further, the lubricant 3 having thixotropic properties can be obtained by mixing and stirring a thixotropic agent such as the aforementioned ultrafine amorphous anhydrous silica or ultrafine clay into a liquid lubricant such as oil.

The embodiment shown in FIG. 1 shows one embodiment showing the most basic configuration, and pocket-shaped storage portions 4 are provided on both sides of the sliding portion.

When the rotating shaft 1 stops rotating, the thixotropic lubricant 3 is gelatinized and naturally exhibits a high viscosity state like grease, and remains in the sliding portion. When the rotation of the rotating shaft 1 starts, the gelatinized state is still maintained at the beginning of the rotation.
Gradually, shear is applied to the sliding portion, and this portion partially turns into a sol, exhibiting a liquid state, and the torque decreases.

The conditions for sol formation are such that the stronger the shear and the longer the time the shear is applied, the more the sol formation tendency progresses.

By the way, in the embodiment shown in FIG. 1, pocket-shaped storage parts 4 are provided on both sides of the sliding part, so that the lubricant 3 in the parts 4 is absorbed by the shearing force at the sliding part with the rotating shaft 1. An appropriate labyrinth gap is formed by channeling without being affected, and most of the lubricant remains gel-like. Therefore, this gel-like lubricant is sheared on the sliding surface and becomes a sol. Can prevent leakage.

FIG. 2 shows that in the storage section 4 of the embodiment shown in FIG.
This shows another embodiment in which a labyrinth seal 5 is provided from the outside to more reliably prevent the lubricant 3 stored in the storage portion 4 from leaking.

Figures 3a and 3b show another embodiment in which a thrust bearing 6 is fixed to the bearing member 2 of the above embodiment to prevent the rotating shaft 1 from shifting in the thrust direction. The difference between the two is that in A, the storage portions 4 are provided on both sides of the sliding portion, whereas in B, the storage portions 4 are provided only on one side. The details are omitted.

In these embodiments, the bearing member 2 is composed of two concentric tubular members 2 ₁ and 2 ₂ , but the action and effect of the thixotropic lubricant 3 are exactly the same as in the embodiments described above. It prevents lubricating oil from leaking and performs the function of a rotating bearing under low torque.

Moreover, FIG. 4 shows an example in which the thrust receiving plate 6a is applied to an aligning plastic bearing.
A spherical bearing member 2a is rotatably supported by a bearing retainer 7.

A pocket-shaped reservoir 4 is formed on one side of the sliding portion opposite to the thrust receiving plate 6a, and is filled with a thixotropic lubricant.
In addition, zigzag-shaped dynamic pressure generating grooves 8 are continuously carved in parallel on the inner circumference of the bearing member 2a in the sliding part, so that very strong shear is applied to the lubricant 3 in the sliding part. Therefore, the lubricant 3, which is gelatinous when stopped, can be quickly converted into a sol and converted into liquid lubricant 3 at the same time as the rotation starts, and therefore has extremely high durability. friction,
It has the advantage of improving wear resistance.

The embodiment shown in FIG. 5 has zigzag-shaped hydrodynamic grooves 8 parallel to each other on the inner periphery of the bearing member 2 constituting the sliding part in the structure of the embodiment shown in FIG. The grooves 8 for generating dynamic pressure shown in FIGS. 4 and 5 of the above embodiment are
The engraving position is not on the bearing member 2 side but on the rotating shaft 1 side.
It is also possible to provide it on the outer periphery of the. Note that the structure of the dynamic pressure generating grooves 8 is not necessarily in a zigzag shape.

Although a number of embodiments of the present invention have been described above, the present invention can be widely implemented in this type of sliding bearing.

In the above embodiment, the conventional crease-filled plastic plain bearing and the
The graph shown in FIG. 6 was obtained by testing the dynamic friction coefficient over time for sliding bearings having the configurations shown in the figures. In other words, when testing was carried out with a radial load of 0.5 kg, a shaft diameter of 10 mm, and a rotation speed of 100 rpm, the coefficient of dynamic friction of conventional plain bearing A remained almost unchanged between the time of startup and after 35 minutes, as shown in Figure 2. It can be seen that the coefficient of dynamic friction of the slide bearing B shown in FIG. Also, the fifth
Since the slide bearing C shown in the figure is provided with the groove 8 for generating dynamic pressure, it can be seen that the coefficient of dynamic friction immediately decreases from the time of startup, and the characteristics are extremely excellent.

According to this invention, the lubricant is provided with thixotropic properties, and pocket-shaped reservoirs are provided on both sides or one side of the sliding portion and filled with the lubricant, so that the sliding portion rotates. When subjected to shearing due to the action, the gelled lubricant becomes a sol and can achieve low friction and high abrasion effects. In addition, the lubricant filled in the pocket-shaped storage part of the sliding part is not susceptible to shearing, so it is stored without changing its gelling state, which prevents the so-called lubricant from flowing out. There is an effect that can be achieved.

Further, according to the present invention, it is structurally sufficient to simply provide a pocket-shaped storage portion in the sliding portion, so that machining of the sliding bearing can be easily carried out.

[Brief explanation of drawings]

1 to 5 are sectional views of essential parts showing numerous embodiments of the sliding bearing according to the present invention, and FIG. 6 is a cross-sectional view of the conventional example and the embodiments shown in FIGS. 2 and 5. It is a graph comparing the relationship between the dynamic friction coefficient and time. DESCRIPTION OF SYMBOLS 1... Rotating shaft, 2... Bearing member, 3... Lubricant having thixotropic properties, 4... Pocket-shaped reservoir, 6... Thrust receiver, 8... Groove for generating dynamic pressure.

Claims (1)

[Scope of Claims] 1. A sliding bearing composed of a bearing member and a rotating shaft, in which a pocket-shaped reservoir is formed on at least one side of the sliding portion of the bearing member, and has thixotropic properties. The sliding part including the reservoir is filled with lubricant, and the gel-like lubricant filled in the reservoir prevents the lubricant that becomes sol from flowing out due to shear generated in the sliding part. Plain bearing. 2. The sliding bearing according to claim 1, wherein the storage portion includes a labyrinth seal. 3. The sliding bearing according to claim 1, wherein the sliding portion comprises a dynamic pressure generating groove in the bearing member or the rotating shaft.