JP2003120676A - Bearing, bearing device and method for manufacturing bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exceed a limit precision attained by a ball bearing in a bearing or a bearing device, to solve various problems such as manufacturing difficulty, abrasion of a shaft and a housing during low speed rotation, and rotation load affected by viscosity of the oil pointed out for a dynamic pressure bearing, and further to realize the solution of the problems at a low cost. SOLUTION: This bearing device (BA) comprises a shaft (1), a thrust plate (5) arranged on an end portion of the shaft, gel (2) coming into contact with a whole surface of the shaft (1) to be supported, and the housing 6 for containing one portion in the vicinity of an end portion of the shaft and the whole portion of the gel. The shaft rotates with the gel serving as the bearing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technical field of a bearing, a bearing device, and a method of manufacturing the bearing device, and in particular, a bearing suitable for use in a device requiring a relatively light load and high speed rotation. It belongs to the technical field of a bearing device and a method for manufacturing the bearing device.

[0002]

BACKGROUND ART In general, ball bearings are the mainstream of rotary bearings, have various sizes and applications, and are the most popular in the market. However, recently, high-speed rotation and high rotation accuracy have been demanded. For example, the bearing accuracy required for a spindle motor for a hard disk drive (HDD) of a computer or the like is a shaft shake (NRRO; Non-Repetition) that is not synchronized with rotation.
ive runout) is required to be 0.1 μm or less.

In this respect, in the ball bearing, NRRO cannot be set to 0.1 μm or less in terms of processing accuracy. Therefore,
In recent years, a dynamic pressure bearing has been considered and put into practical use in place of it. Here, the dynamic pressure bearing has a structure in which a gap is provided between the surface of the shaft and the inner peripheral surface of the bearing facing the shaft, and a groove is formed in the inner peripheral surface, and oil or air is provided in the gap. It means a bearing that rotates with the shaft not directly contacting the inner peripheral surface with the interposition of the above. According to this dynamic pressure bearing, NRRO
It is possible to clear below 0.1 μm.

Incidentally, in any of the bearings, conventionally, the bearing main body is generally made of martensitic stainless steel, or ceramics such as silicon nitride, carbon nitride, or zirconia.

[0005]

However, the conventional dynamic pressure bearing has the following problems.

That is, first, extremely high precision processing / manufacturing is required. As described above, in the dynamic pressure bearing, a gap is provided between the shaft surface and the inner peripheral surface of the bearing, but the clearance is generally required to be several μm or less. Further, the groove formed on the inner peripheral surface of the bearing cannot be generally formed without a special process, and the groove is also required to be machined with extremely high accuracy. Further, if the oil or the like filled in the gap leaks to the outside, it will affect the operating characteristics. Therefore, it is necessary to assemble the bearing as a whole with high accuracy, and it is necessary to separately take measures against oil leakage. Not rare. As described above, the dynamic pressure bearing requires expensive parts, difficulty in assembling, oil leakage countermeasures, and the like, which require extremely high-precision machining / manufacturing and manufacturing precautions. I will end up.

Further, the dynamic pressure bearing has a problem that sufficient dynamic pressure is not generated during low speed rotation such as start and stop of the shaft. For this reason, there is a possibility that the shaft and the bearing or the housing may come into contact with each other, and in addition, both may be worn. Further, due to the property of the oil used as the dynamic pressure medium, there is a problem that the rotation load becomes large not only during the low speed rotation but also during the normal rotation in some cases.

The present invention has been made in view of the above problems, and exceeds the limit accuracy that can be achieved by a ball bearing, and is difficult to manufacture, which is pointed out in a dynamic pressure bearing, and a shaft and a housing at low speed rotation. It is an object of the present invention to provide a bearing, a bearing device, and a method of manufacturing a bearing device, which can solve various problems such as wear of the bearing, high rotational load affected by oil, and the like, and can achieve them at low cost.

[0009]

In order to solve the above problems, the bearing of the present invention comprises a gel which contacts all or part of the surface of the shaft to be supported.

The bearing of the present invention is characterized in that the conventional bearing is made of gel, unlike the conventional bearing made of steel or ceramics as described above.

The term "gel" as used herein means a state in which colloidal particles or polymer solutes lose their independent motility due to interaction and are aggregated while having a solidified structure (edited by the Chemistry Dictionary Dictionary, edited by the Committee for Chemistry). See "Chemical Dictionary", Kyoritsu Publishing Co., Ltd.). The gel contains a solvent or dispersion medium such as water or oil in the gap formed by the polymer solute or the like, and can maintain its shape while swelling up to several thousand times its own weight. Here, the degree of swelling, that is, how much solvent can be absorbed is largely controlled by the density of the polymer network and the number of charges. In other words, the gel generally has a structure in which a three-dimensional polymer network is a skeleton, and water and oil, and in some cases, a solvent such as magnetic fluid is absorbed and expanded. Therefore, it can be said that it is soft but maintains its shape like a solid. According to the above-mentioned dictionary, regarding the solidified gel containing the dispersion medium,
Although the name "jelly" is given, in the present specification, this "jelly" is also referred to as "gel" (in the above dictionary, "gel in a narrow sense means jelly"). It is said that.).

As such a gel, more specifically,
Examples include gels composed of polysaccharides, protein gels, gels composed of synthetic polymers, and the like. More specifically, the proper names are Gellan gel, κ-carrageenan gel, polyvinyl alcohol (P
Examples thereof include VA) gel, sodium poly-2-acrylamido-2-methylpropanesulfonate (PNaAMPS) gel, polynobornene, and gels of crosslinked alkylallate.

In the present invention, such a gel is
It contacts all or part of the surface of the shaft to be supported. Here, "contacting all ..." means that the shaft is supported substantially only by the gel. That is, in the bearing in this case, the shaft has an appearance as if it penetrates or is embedded in the gel, and the shaft rotates in that state. Further, “contacting a part” means, for example, a plurality of cylindrical portions sandwiched between two cross sections located at relatively short distances in the longitudinal direction of the shaft, and the plurality of cylindrical portions are formed by the gel. The state of being supported, the state in which the end or end face of the shaft is supported by the gel, and the like. That is, basically, in any case, if the shaft is supported by the gel in some way, it corresponds to the “contact in whole or in part” according to the present invention.

In any case, according to the present invention, it is generally assumed that the shaft is rotated while the contact between the gel and the shaft is maintained. That is, the rotation and the like of the shaft according to the present invention are performed while the surface of the shaft and the surface of the gel which are in contact with each other are slid or while frictional forces are applied to each other.

It is known that the friction phenomenon between the gel and some solid material or its mechanism has various unique properties. Among these unique properties, the first point is solid state physics Vol. 36 No. 2 2001.
p103-111 (Takashi Kadada * Kenshi * (* is “co-” under “dragon”) and Yoshihito Nagata) (hereinafter referred to as “reference 1”)
Et al., The friction coefficient and frictional force of the gel surface are extremely small compared to solids, and the frictional force is not simply proportional to the load. By the way, the friction between solids is F as the frictional force, W
As is well known, when F is the load and μ is the friction coefficient, it can be described by the formula F = μW (1). Therefore, the frictional force F is proportional to the load W. However, the above equation does not simply hold between the gel and the solid surface.

Here, in the above-mentioned reference 1, as a type of load dependence observed in friction between the gel and the solid surface,
It can be roughly classified into the following three categories. That is, (I) a type having no load dependency, (II) a type having a slight load dependency, and (III) a type having a load dependency close to that of a solid. Of these, the gel of type (I) specifically includes the gellan gel described above and other polysaccharide gels derived from sea soup, and the gel of (II) does not have other charges such as PVA gel. Gel, etc. (II
In I), PNaAMPS gel and other gels having a large number of charges are applicable.

However, in any type of gel, the frictional force of the gel is extremely smaller than that of the solid, and the size thereof is 1/100 to 1 as compared with the solid.
It is about / 1000.

As described above, according to the present invention, the gel has a property of maintaining a solid shape while swelling, and exhibits excellent lubricity with a solid material, whereby The same effect as or more than the non-contact support of the pressure bearing or the like is achieved, and the suitable effect of the support of the shaft is realized and the motion of the shaft is smoothly achieved.

More specifically, first, with respect to the above-mentioned "suitable support", by supporting the shaft with the gel according to the present invention, the gel has a flexibility like that between solid and liquid. Since it is provided, since there is no mechanical contact portion like the dynamic pressure bearing, it is possible to suppress NRRO to 0.1 μm or less. Further, there is no need to worry about contact between the shaft and the housing during low-speed rotation, which is a problem in the dynamic pressure bearing. The reason why such a phenomenon occurs in the dynamic pressure bearing is that sufficient dynamic pressure is not generated, but in the present invention, the gel that maintains a solid shape can always sufficiently support the shaft. is there.

Regarding the above-mentioned "to realize the motion smoothly", in the dynamic pressure bearing, a large rotational load may be applied depending on the property (eg, viscosity) of the oil. You don't have to worry. That is, according to the present invention, regardless of whether the shaft moves at low speed or at high speed, the shaft can be smoothly moved in any state. This is because, as described above, the frictional force is basically 1/100 to 1 compared to that of a solid, regardless of which gel is selected.
/ 1000, that is, the fact that excellent lubricity is exhibited between the gel and the shaft.

In addition to the above, according to the present invention, it is possible to obtain various operational effects described below.

First, it is easy to manufacture. That is, according to the present invention, for example, the bearing device can be almost completed only by forming a shape in which the shaft is wrapped with gel. Further, as is well known, there is no particular difficulty in producing the gel itself. In this respect, the dynamic pressure bearing is, as described above, significantly different from the place where high precision machining / manufacturing is required. In addition, in this connection, the bearing according to the present invention has a simple structure as described above, and therefore can be easily downsized.

Secondly, in the bearing according to the present invention, the rotation direction is not limited to one direction unlike the dynamic pressure bearing. That is, the shaft can be rotated in either the left or right direction.
Further, the present invention can be applied even when the shaft moves linearly. From these, it is obvious that the scope of application of the present invention is significantly expanded.

Thirdly, according to the present invention, since the frictional resistance is small as described above, it is possible to suppress the generation of heat and noise due to rubbing such as rotation as compared with a ball bearing or the like.

Fourthly, in the dynamic pressure bearing, it was necessary to give special consideration to the scattering of oil, but in the bearing according to the present invention, there is almost no need to worry about it. The gel has a solvent that is absorbed in the polymer network, but since the adsorption is strong, the scattering or the like hardly occurs.

By the way, in the above-mentioned document 1, gel-
Regarding the friction phenomenon between solid surfaces, in addition to the high lubricity described above, various other unique properties described below are described. First, the frictional force of the gel depends on the apparent contact area (contact area dependency). In this respect, in the solid-solid friction, as can be seen from the above formula (1), the friction force F
Does not depend on the contact area (that is, substantially only on the load W). It is explained that this is because in the contact between solids, the convex portions existing on the surfaces of the solids are in contact with each other. In other words, the frictional force generated between the solids and the solids may be theoretically dependent on the contact area between the convex portions, that is, the true contact area. Thinks that does not depend. However, this theory does not hold between the gel and the solid surface. It is believed that this is because the gel surface has high flexibility and can be freely deformed according to the microscopic shape of the solid surface that is the contact partner.

Further, the frictional force between the gel and the solid surface largely depends on the property of the solid surface (solid surface dependency). It is considered that this is because the mechanism of interaction between the gel and the solid surface changes depending on the type of charge in the gel and the difference in charge. In the above literature 1, for example, PVA
Even on glass, gels
Tetrafluoroethylene; so-called "Teflon (registered trademark)") shows almost the same frictional force, but PNaA
MPS gel is 1 on Teflon® on glass.
It has been reported to have a friction force of / 100.

In the present invention, the bearing according to the present invention can be constructed more suitably by taking appropriate consideration of these properties. That is, first, according to the above-mentioned contact area dependency, it is considered that the contact area of the shaft and gel according to the present invention can be set within a range generally considered to be appropriate. For example, in the above document 1, the frictional force F between the gel and the solid surface is expressed as follows, where W is the load and A is the apparent contact area. F∝W ^α A ^β (α + β≈1) (2) That is, as the contact area A increases, the frictional force F also increases with the β power. If such an expression (2) is used as an index, the frictional force F that may be generated between the gel and the shaft
Also, the shape of the gel according to the present invention can be suitably configured by taking into consideration the size of the bearing that is allowed by design, the size of the contact area required to support the shaft, and the like.

On the other hand, according to the above solid surface dependence,
In the bearing according to the present invention, it is suggested that there is an appropriate combination of gel type and shaft material. For example, only from the above, it can be said that the PNaAMPS gel is more advantageous than the PVA gel in that high lubricity is obtained. The shaft is made of conventional material,
It is also conceivable to coat some material on the surface of the shaft in order to achieve the appropriate combination.

As described above, various variations can be considered for the bearing according to the present invention, but in any case, it is still within the scope of the present invention.

By the way, as a theoretical framework for explaining the above-mentioned peculiar friction phenomenon between the gel and the solid surface, the so-called "repulsion / adsorption theory" as shown in the above-mentioned Document 1. It is provided. Hereinafter, the repulsion / adsorption theory will be described by appropriately extracting / summarizing the document 1.

In the repulsion / adsorption theory, when a polymer solute or a polymer network (that is, "gel") containing a solvent comes into contact with a solid surface, the interaction occurring at the interface is considered in two cases. That is, one is the case where the polymer chains are repelled from the solid surface, and the other is the case where the polymer chains are adsorbed. The former corresponds to the affinity (interfacial energy) between the polymer chain and the solid surface being smaller than the affinity between the solvent and the solid surface, and the latter corresponds to the opposite. Further, it can be considered that in the former case, repulsive force works between the polymer chain and the solid surface, and in the latter case, attractive force works.

First, when the polymer chain is repelled, that is, when the repulsive force acts between the gel and the solid surface,
A polymer chain deficient layer is formed at the interface between the two, and a solvent layer is formed instead. Therefore, the frictional force between the gel and the solid surface in this case can be explained by incorporating the theory relating to the frictional phenomenon of the fluid, and as a result, the frictional force is generally considered to be small. Here, since the theory relating to the friction phenomenon of a fluid can be considered as Newton's theorem which explains the viscous resistance of a fluid in contact with a solid, the magnitude of the frictional force depends on the viscosity of the solvent, the gel It is proportional to the relative moving speed of and is inversely proportional to the thickness of the solvent layer. So in this case,
It is considered that when the load applied to the gel is large, the thickness of the water layer is small and thus the frictional force is large, and conversely, when the load of the water layer is large, the frictional force is small. That is, it is considered that the load dependency of the frictional force is increased.

On the other hand, when polymer chains are adsorbed, that is, when an attractive force acts between the gel and the solid surface,
The frictional force between the two can be explained by the elastic force when the adsorbed polymer chains are stretched. Here, the amount of stretching in the case where the "polymer chain is stretched" is proportional to the friction rate, that is, the product of the stretching rate of the polymer chain and the adsorption time or adsorption lifetime of the polymer chain on the solid surface. . And, this adsorption lifetime largely depends on the relative migration speed between the gel and the solid surface. Therefore, in this case, the frictional force is expected to have a velocity dependency, and in the above-mentioned Document 1, generally, the frictional force is large at a low speed and the frictional force is small at a high speed. . Also in this case, the load dependency is recognized similarly to the case where the repulsive force works, and when a small load is applied, the friction force does not depend on the load (that is, the friction force is constant). However, a constant load dependence is recognized only when a large load is applied.

The difference between these two cases depends on the type of gel. That is, for example,
In the PNaAMPS gel described above, repulsive force acts between the gel and the solid surface, and in PVA gel, attractive force acts. Therefore, in PNaAMPS gel, the friction between the solvent layer and the solid surface is substantially discussed, and in PVA gel,
Friction will be discussed with the elastic force when the polymer chains are stretched.

According to the above-mentioned document 1, generally, the frictional force is always smaller when the repulsive force acts between the gel and the solid surface than when the attractive force acts.

According to the above theory, it is clear that it serves as an index for specifically selecting the gel according to the present invention. That is, for example, in the case where the repulsive force acts between the gel and the solid surface, the frictional force becomes smaller than in the case where the attractive force acts. Therefore, if higher lubricity is required, it is preferable to select such a gel type. It can be said that it is preferable. However, in any of the above cases,
As described above, the frictional force observed between the gel and the solid surface is still much lower than the frictional force generally observed between the solid and solid. Even a gel having a mechanism can be used without causing a big problem.

In summary, in the present invention, it can be said that it is generally preferable to select a gel in which a repulsive force acts between the gel and the solid surface, but the basic standpoint is what kind of gel is used. Even things are within the range.

Further, more specifically, in the case where a repulsive force acts between the gel and the solid surface, as described above, the viscosity of the solvent also affects the frictional force, so an appropriate solvent should be selected. Clearly, etc. are effective. In addition, in this case, since the load dependence of the frictional force becomes large, it is possible to determine the most suitable load to be applied between the shaft and the gel. It is considered that these can be appropriately determined experimentally, empirically, theoretically, or by simulation.

Further, even in the case where an attractive force is exerted between the gel and the solid surface, as described above, there are cases where there is no load dependency up to a load of a predetermined magnitude, so this is positively considered. It is also possible to use. For example, as will be described later, it is conceivable to apply a pressure to such a gel so as to increase its rigidity but not to change the frictional force.

As described above, a high lubricity is generally exhibited between the gel and the solid material. However, if a certain device is added to the method for producing the gel, a higher lubricity (hereinafter, It is known that it is possible to obtain "ultra high lubricity" for convenience. This is the Journal of The American Chemical Society 200
1 Vol.123 No.23 P5582-5583 Synthesis of Hydrogels
with Extremely Low Surface Friction (Jian Ping Gon
g et al.) (hereinafter referred to as “Reference 2”), the material of the gel and the material of the base material used when synthesizing the gel are selected so as to be an appropriate combination. By doing. For example, polystyrene (polyst
yrene) is prepared and PAMPS gel is synthesized on the substrate, the maximum is 1 /
It is shown in Document 2 that a low frictional force of 100 or less is observed.

In addition, in the above-mentioned Document 2, as the base material,
Instead of the above polystyrene, Teflon (registered trademark),
The same effect can be obtained by using polyethylene, polypropylene, polyvinyl chloride, polymethylmethyl acrylate (PMMA), or the like. Further, as a gel that can enjoy such effects, for example, acrylic acid,
It can be mentioned gels composed of water-soluble vinyl monomers such as acrylamide and sodium salt of styrene sulfonic acid.

According to the above-mentioned document 2, it is possible to reduce the frictional force.
When the above-mentioned polystyrene or polytetrafluoroethylene having hydrophobicity is used as the base material, a large number of unbound polymer chains (dangli) are formed on the surface of the gel synthesized on the base material.
As a result of the formation of ng polymer chains), when this gel comes into contact with a solid material, the thickness of the layer of water, which is the solvent formed between both members, increases and the frictional force decreases. There is.

According to this theory, it is possible to obtain ultra-high lubricity if a certain number or more of unbonded polymer chains are present on the surface of the gel. The present invention naturally includes such aspects.

The application range of the bearing according to the present invention is basically not limited, but when it is applied as a bearing which is a component of a heavy machine, it can withstand a heavy pressure. It is considered necessary to solve new issues such as selection of. From the above, it can be said that the bearing according to the present invention is generally preferable when applied as a bearing constituting a device that requires high-speed rotation under a relatively light load. In addition, as such a device,
For example, a spindle motor for a HDD of a computer or the like, a spindle motor for a polygon mirror, or the like can be given.

In one aspect of the bearing of the present invention, the gel is
It includes a ring-shaped portion that is arranged concentrically with the shaft and is in contact with the inner peripheral surface thereof.

According to this aspect, it is possible to favorably support the shaft in accordance with the performance required for the bearing. For example, in the present aspect, it can be seen that the gel has a shape suitable for use as a so-called rotary bearing due to the arrangement in which the shaft penetrates the inside of the ring.

[0048] In another aspect of the bearing of the present invention, the gel includes a button-shaped portion which is concentrically arranged at the tip of the shaft and is in contact with the circular surface thereof.

According to this aspect, it is possible to support the shaft at its tip.

In this aspect, a thrust plate is provided at the tip of the shaft, and the button-shaped portion may be configured to contact the circular surface of the thrust plate. .

According to this structure, it is suitable for use as a so-called thrust bearing, and it is possible to more reliably support the shaft according to the area of the strut plate.

In another aspect of the bearing of the present invention, a thrust plate is provided at the tip of the shaft, and the gel is
A ring-shaped portion is concentrically arranged on the thrust plate and is in contact with a surface of the thrust plate located around the shaft at an annular surface thereof.

According to this aspect, it becomes a form suitable for use as a so-called thrust bearing, and it becomes possible to more surely support the shaft in accordance with the area of the strut plate. In particular, if the strut plate is sandwiched between the button-shaped portion and the ring-shaped portion, the shaft can be supported more reliably.

In another aspect of the bearing of the present invention, a pressure is applied to the gel.

According to this aspect, it is possible to increase the rigidity of the gel by applying a pressurizing force. That is, it becomes possible to more reliably support the shaft.

In this embodiment, the degree of preload to be applied to the gel is not basically limited, but a pressure within the range where the gel is not decomposed or destroyed can be considered as the upper limit. Further, the degree of pressurization can be changed depending on the type of gel, the usage conditions of the bearing, and the like.

Further, as the gel according to this embodiment, it is preferable to select a gel in which the frictional force is not increased as much as possible by applying a pressure. This is because, in this way, it is possible to more suitably realize both of the properties that are generally considered to be contradictory, that is, the certainty of the support of the shaft and the non-interference of the motion of the shaft. Is. By the way, in the solid-solid friction, it is impossible to achieve the property that the frictional force does not increase even if a load is applied, as is clear from the formula (1). Can be said to have extremely remarkable characteristics by itself.

By the way, when selecting the gel as described above, the repulsion / adsorption theory described above may be used. That is, according to this theory, it is found that the above condition is generally satisfied if a gel in which a repulsive force acts between the gel and the solid surface is selected.

More specifically, gellan gel or other seaweed-derived polysaccharide gel, PVA gel or other non-charged gel may be used.

Among them, the gellan gel and other polysaccharide gels derived from sea soup have been reported in the above-mentioned Document 1. That is, in the gel, the frictional force does not show load dependence up to a certain load, but at a load exceeding that, the frictional force sharply decreases as the load increases. It can be easily imagined that such a property will bring a great effect depending on the usage method.

In order to solve the above-mentioned problems, the bearing device of the present invention comprises the above-mentioned bearing of the present invention (however, including various aspects thereof) and a housing for accommodating the gel.

According to the bearing device of the present invention, it is possible to expect not only the shaft support by the gel but also the shaft support by the housing. In this case, as described above, if the gel is brought into contact with the entire surface of the shaft to be supported, for example, the entire interior of the substantially cubic housing is filled with the gel and the shaft penetrates or is embedded in the gel. It is also possible to adopt a form as described above. In addition, if the gel is brought into contact with a part of the shaft to be supported, a mode in which a partition plate or the like is provided at an appropriate position inside the housing and the gel is provided at a position where the partition plate is not provided may be considered.

In this embodiment, the material of the housing is not particularly limited, and various metals and ceramics can be used. However, the contact surface between the housing and the gel is less lubricious. However, since it can be said that it is desirable to generate more friction, it is preferable to select an appropriate material that meets such conditions by considering the combination of the gel and the solid material described above.

Further, in order to realize such relative fixing of the housing and the gel, in addition to or instead of the selection of the above-mentioned material, for example, the shape of the housing itself is a triangular prism or a cubic shape. It is advisable to take other measures such as forming a shape having other corners or providing a protrusion or a recess (that is, a protrusion or a recess) inside the housing. This ensures that the gel inside the housing
The position cannot be changed easily.

In one mode of the bearing device of the present invention, the shaft has a thrust plate at a predetermined position in the longitudinal direction thereof, the thrust plate is disposed in the housing, and the end portion of the shaft is the It is located outside the housing.

According to this aspect, the shaft portion including the strass plate is covered with gel from four sides, so that the shaft can be more reliably supported. In particular, in the case where the "predetermined part" referred to in the present invention corresponds to the central part of the shaft, the housing accommodates the thrust plate provided in the central part of the shaft, It is possible to significantly reduce eccentricity and vibration during rotation.

Alternatively, in another aspect of the bearing device of the present invention, the shaft has a thrust plate at its tip, and the thrust plate is arranged in the housing.

According to this aspect, since the tip of the shaft provided with the thrust plate is covered with gel from four sides, the shaft can be more reliably supported.

In another aspect of the bearing device of the present invention, the housing functions as a manufacturing container for synthesizing the gel.

According to this aspect, the housing can be used not only as a container for storing the gel when the bearing is actually used but also as a container for manufacturing the gel.

When the housing is used as a manufacturing container and a storage container at the time of actual use as in the present embodiment, the selection of the material for forming the housing is described in, for example, Document 2 above. It is preferable to pay attention to the theory that the frictional force of the gel is affected by the choice of substrate.

In order to solve the above-mentioned problems, a method for manufacturing a bearing device according to the present invention is a method for manufacturing a bearing device, wherein the housing in the above-mentioned bearing device according to the present invention functions as a manufacturing container. The method includes the steps of injecting the raw material of the gel into the housing that accommodates a part of the shaft, and thereafter, gelling the raw material to form the gel.

According to the method of manufacturing a bearing device of the present invention, for example, a substantially cubic housing is prepared, and the shaft is penetrated through the two opposing surfaces, or one end of the shaft is embedded in the housing. After fixing this by an appropriate means, inject gel raw material into the inside of the housing to gelate it (step where the housing functions as a manufacturing container), and then store the gel as it is. And acting as one member for realizing the support of the shaft (at the stage where the housing functions as a storage container), and the like.

In the above, the method of "gelling" the raw material generally differs depending on whether the gel is a chemical gel or a physical gel. Here, the "chemical gel" is one in which a bridge of polymer chains is formed by a chemical reaction and is also called "irreversible gel", and the "physical gel" is the bridge. The bridge is formed by aggregation due to hydrogen bond or ionic bond or physical entanglement of polymer chains, and is also called "reversible gel". Since the bridging mechanism is different (that is, the construction mechanism of the three-dimensional mesh is different) as described above, the manufacturing methods of the two are also different. The following is "Gel Handbook" written by Hidetaka Tobita and others (NTS, 199).
With reference to the matters described in (November 28, 7), the "gelling" of chemical gels and physical gels will be mentioned.

First, the chemical gel is roughly classified into a method of crosslinking during the polymerization reaction of the raw materials and a method of synthesizing the linear polymer and then crosslinking by a chemical reaction. The former is classified into a polycondensation method and a radical polymerization method. Among them, the radical polymerization method further includes a thermal polymerization method, a radiation polymerization method, a photopolymerization method and a plasma polymerization method. In the latter case, there are a method of crosslinking a functional group of a polymer, a method of radiation crosslinking, a method of photocrosslinking, a method of plus-crosslinking, and the like.

On the other hand, “gelling” of a physical gel can be generally easily performed as compared with that of a chemical gel. Generally speaking, gelation can be achieved by mixing or cooling the raw materials, and more specifically, there are, for example, a freeze-drying method, a freeze low-temperature crystallization method, a mixing method and the like. However, even in the case of gels synthesized by the same method, the mechanism of crosslinking generally differs depending on the type of the gel, and examples thereof include hydrogen bond cross-linking, ionic bond cross-linking, coordinate bond cross-linking, cross-linking by helix formation, and hydrophobic Bond crosslinks and the like will appear.

As described above, there are various methods for "gelling", and any of them is
It is still within the scope of the invention.

The operation and other advantages of the present invention will be apparent from the embodiments described below.

[0079]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) First, the first embodiment of the present invention
Embodiments will be described with reference to FIGS. 1 and 2. Here, FIG. 1 is a cross-sectional view of the bearing device according to the first embodiment, and FIG. 2 is an explanatory view schematically showing the structure of the gel.

In FIG. 1, a bearing device BA includes a shaft 1 and a thrust plate 5 provided at an end portion of the shaft 1 and a gel 2 which comes into contact with the entire surface of the shaft 1 having such a structure to be supported. Further, it is composed of a housing 6 for accommodating a part near the end of the shaft 1 and the entire gel 2.

Of these, the shaft 1 and the thrust plate 5 can be made of various materials such as a metal material.
However, as a material forming the shaft 1 and the thrust plate 5, it is possible to select a generally preferable material from the viewpoint of obtaining higher lubricity in relation to the gel 2 described later. That is, it is possible to select a suitable combination of the type of the gel 2 and the material of the shaft 1 and the thrust plate 5 according to the type of the gel 2. Further, in some cases, the surfaces of the shaft 1 and the thrust plate 5 may be coated with such a suitable material.

As can be seen from FIG. 1, the gel 2 has the function of a member itself which is conventionally called a "bearing". That is, the shaft 1 and the thrust plate 5 are
Operates such as rotation in a state of being wrapped by the gel 2.

For example, as shown in FIG. 2, such a gel 2 has a structure in which a three-dimensional polymer network is used as a skeleton, and water and oil, and in some cases, a solvent such as a magnetic fluid is absorbed and expanded. It is soft and maintains its shape like a solid. More specifically, the gel is composed of a polysaccharide gel, a protein gel, a synthetic polymer gel, and the like. More specifically, gellan gel, κ-carrageenan gel, polyvinyl alcohol (PVA) gel, sodium poly-2-acrylamido-2-methylpropanesulfonate (PNaA).
MPS) gel, polynobornene, gels such as alkylallate crosslinked products, and the like can be used.

The housing 6 is formed into a substantially cubic shape as shown in FIG. 1, and the gel 2 is arranged so as to fill the entire inside of the housing 6. Thus, in the first embodiment, since the housing 6 has a substantially cubic shape, for example, when the shaft 1 rotates,
Even if a rotational force is applied to the gel 2, the position of the gel 2 cannot be easily changed by the corner portion of the housing 6 having a substantially cubic shape. In order to make such an effect more reliable, it is advisable to further take measures such as providing a protrusion or a recess (that is, a protrusion or a recess) inside the housing 6. By doing so, the protrusion or the recessed portion plays a role of a so-called stopper, so that the gel 2 can be more reliably fixed.

The housing 6 can be made of various materials such as metal materials and ceramics. However, as can be seen from the above, between the housing 6 and the gel 2, rather than high lubricity,
Since it is generally preferable to generate a high frictional force, it is more preferable to use both materials in such a combination.

In the bearing device BA having such a structure,
While the contact between the gel 2 and the shaft 1 and the thrust plate 5 is maintained, the shaft 1 is rotated. That is, the rotation of the shaft 1 according to the present embodiment is performed while the surface of the shaft 1 and the surface of the gel 2 which are in contact with each other are slid or while frictional forces are applied to each other. Further, in this embodiment, the thrust plate 5 is provided at the end of the shaft 1, so the gel 2 also functions as a thrust bearing.

Then, the bearing device B having such a configuration
In A, the gel 2 has the property of maintaining a solid shape while swelling, and exhibits excellent lubricity with a solid material, so that the shaft is supported by a non-contact type dynamic bearing or the like. As well as or more than that, it is possible to realize suitable support of the shaft 1 and smoothly realize the movement of the shaft 1.

The bearing device BA as shown in FIG. 1, particularly the gel 2 can be manufactured as follows. That is, for example, after the housing 6 and the shaft 1 and the thrust plate 5 are prepared in advance in the arrangement shown in FIG. 1, the shaft 1 and the thrust plate 5 are fixed outside the housing 6 by an appropriate means, and then the gel 2 The gel 2 is molded by injecting the above raw material into the housing 6 and gelling the raw material by an appropriate means. Here, the "appropriate means" for realizing "gelation" differs depending on whether the gel 2 is a chemical gel or a physical gel, and in the former case, for example, a bridge is formed during the polymerization reaction of the raw material. The method corresponds to a method such as radical polymerization using heat, radiation, light, plasma or the like, and in the latter,
For example, a freeze-drying method, a freeze low-temperature crystallization method, a mixing method and the like are applicable.

As described above, according to the first embodiment, the bearing and the bearing device BA can be manufactured very easily.

Incidentally, in the case of the manufacturing method as described above, the housing 6 has the bearing device BA according to the first embodiment.
In addition to functioning as a manufacturing container for the gel 2 in FIG.
Will function as an auxiliary support member of the.

(Second Embodiment) Next, the second embodiment of the present invention
Embodiments will be described with reference to FIG. FIG. 3 is a cross-sectional view of the bearing device according to the second embodiment.

In FIG. 3, instead of the thrust plate 5 being provided at the end of the shaft 1 in FIG. 1, the thrust plate 5 is provided at substantially the center of the shaft 1 and both ends of the shaft 1 are provided. It penetrates through two opposite surfaces of the housing 6 (that is, the housing 6
Penetrates itself. 1) and the rest of the configuration is the same as in FIG.

Even in such a form, the same effect as described above can be obtained. Assuming that the thrust plate 5 shown in FIG. 3 is removed from the shaft 1, it is possible to easily imagine a form in which the shaft 1 moves vertically in the drawing. Even in such a form, the gel according to the invention still exhibits the same effect as described above.

(Third Embodiment) Next, a third embodiment according to the present invention will be described.
The embodiment will be described with reference to FIG. FIG. 4 is a cross-sectional view of the bearing device according to the third embodiment.

In FIG. 4, the gel 2 in FIGS. 1 and 3 is arranged so as to be filled inside the housing 6, but as shown by reference numerals 3 a, 3 c and 4, a ring-shaped and The shape of the gel and its arrangement are changed, such as a button shape, and the housing 6
The remaining structure is the same as that of FIG. 1 except that a partition 61 is provided inside.

The ring-shaped gels 3a and 3b and the button-shaped gel 4 can be molded by, for example, injecting the gel into a mold prepared in advance to cause gelation. And a ring-shaped gel 3 such as these
According to a and 3b and the button-shaped gel 4, the shaft 1 and the thrust plate 5 can be favorably supported depending on the performance required of the bearing and the like. That is, the ring-shaped gels 3a and 3b are suitable for application to a rotary bearing as shown in FIG. 4, and the button-shaped gel 4 is also suitable for application to a thrust bearing.

Further, in the third embodiment, a partition 61 is provided in the housing 6 in order to effectively fix the ring-shaped gels 3a and 3b and the button-shaped gel 4 as described above. That is, the partition 61 is formed in such a shape as to press the ring-shaped gels 3a and 3b from both sides (the upper surface and the lower surface in the drawing) of the ring-shaped gels 3a and 3b, and to be closely attached to the side surface of the button-shaped gel 4 in the drawing. It is formed in a shape.

According to such a configuration, the shaft 1 and the thrust plate 5 are supported by contacting a part of the surface to be supported with the gel. Therefore, even in such a form, the same effect as described above can be obtained.

In the various embodiments described above, the gel 2 or the ring-shaped gels 3a and 3b and the button-shaped gel 4 are used before the bearing device is actually used.
On the other hand, it is preferable to apply a predetermined pressure. This will increase the rigidity of these gels,
It is possible to strengthen the support of the shaft 1 and the thrust plate 5.

Here, the degree or strength of the preload to be applied to the gel is not basically intended to limit the present invention, but the upper limit is the pressure within the range where the gel is not decomposed or destroyed. Can be thought of as The degree of this pressurization can be changed depending on the type of gel, the usage conditions of the bearing, and the like. Further, as a method of applying pressure to the gel, for example, in the first embodiment, one of the surfaces of the housing 6 having a substantially cubic shape shown in FIG. 1 is configured as an openable door. A method may be adopted in which the door is opened when the pressurizing load is applied, and the door is closed after the pressurizing load is completed. In addition, ring-shaped gels 3a and 3b
As for the button-shaped gel 4, a method of applying a pressure immediately after molding may be adopted.

However, in such a case, it is preferable to use a gel that does not affect the frictional characteristics between the gel and the solid surface by applying a pressure. As such a gel, for example, the repulsion
In the adsorption theory, a gel in which a repulsive force acts between the gel and the solid surface, more specifically, gellan gel or other seaweed-derived polysaccharide gel, PVA gel or other non-charged gel may be selected.

The present invention is not limited to the above-described embodiments, but can be appropriately modified within the scope of the gist or the concept of the invention which can be read from the claims and the entire specification, and accompanying such modifications. The bearing, the bearing device, and the method for manufacturing the bearing device are also included in the technical scope of the present invention.

[0104]

As described above in detail, according to the bearing or the bearing device of the present invention, a suitable shaft support can be achieved at least as much as or more than the non-contact shaft support such as a dynamic pressure bearing. In addition, the movement of the shaft can be smoothed.
Further, it is possible to suppress the generation of heat and noise due to rubbing such as rotation as compared with ball bearings, and it is almost unnecessary to give special consideration to the scattering of oil.

In addition, the bearing or bearing device of the present invention is
It is easy to manufacture, and particularly according to the method for manufacturing a bearing device of the present invention, the bearing device of the present invention can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a bearing device according to a first embodiment of the present invention.

FIG. 2 is an explanatory view schematically showing the structure of a gel.

FIG. 3 is a cross-sectional view of a bearing device according to a second embodiment of the present invention, which is a cross-sectional view showing a mode of a shaft and a mode in which a thrust plate is attached to the shaft in a different position from FIG. 1.

FIG. 4 is a cross-sectional view of a bearing device according to a third embodiment of the present invention, which is a cross-sectional view showing a mode in which a gel aspect is different from that in FIG. 1.

[Explanation of symbols]

1 ... axis 2 ... gel 3a, 3b ... Ring-shaped gel 4 ... Button gel 5 ... Thrust plate 6 ... Housing 61 ... Partition

Claims (11)

[Claims] 1. A bearing comprising a gel that contacts all or part of the surface of the shaft to be supported. 2. The bearing according to claim 1, wherein the gel includes a portion which is arranged concentrically with the shaft and which is formed in a ring shape so as to be in contact with the inner peripheral surface thereof. 3. The gel comprises a button-shaped portion that is concentrically arranged at the tip of the shaft and that contacts on the circular surface of the shaft. Bearing described in. 4. The thrust plate is provided at the tip of the shaft, and the button-shaped portion contacts the circular surface of the thrust plate. Bearing described. 5. A thrust plate is provided at a tip end portion of the shaft, and the gel is arranged concentrically with the thrust plate and is formed on a surface of the thrust plate located around the shaft. The bearing according to any one of claims 1 to 4, further comprising a ring-shaped portion that is in contact with the annular surface. 6. The bearing according to claim 1, wherein a pressure is applied to the gel. 7. A bearing device comprising: the bearing according to claim 1; and a housing that houses the gel. 8. The shaft has a thrust plate at a predetermined position in the longitudinal direction thereof, the thrust plate being disposed inside the housing, and the end portion of the shaft being disposed outside the housing. The bearing device according to claim 7, wherein: 9. The bearing device according to claim 7, wherein the shaft has a thrust plate at its tip, and the thrust plate is arranged in the housing. 10. The bearing device according to claim 7, wherein the housing functions as a manufacturing container when synthesizing the gel. 11. A method for manufacturing a bearing device according to claim 10, wherein the gel raw material is injected into the housing in a state where a part of the shaft is accommodated. Then, a step of forming the gel by gelling the raw material, and a method of manufacturing a bearing device.