JP2004052999A - Fluid bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance molding accuracy and functionality of a housing. <P>SOLUTION: The housing 7 is molded by making a bearing sleeve 8 as an insert article. The housing 7 is made of resin and is constituted of a seal part 7a, a main body part 7b and a bottom part 7c. The seal part 7a and the main body part 7b are a member molded by resin by making the bearing sleeve 8 as the insert article. By welding the bottom part 7c to the member, the housing 7 is integrated. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hydrodynamic bearing device that supports a rotating member with an oil film formed in a bearing gap. This bearing device includes motors for information equipment, such as magnetic disk devices such as HDDs and FDDs, optical disk devices such as CD-ROMs and DVD-ROMs, spindle motors such as magneto-optical disk devices such as MDs and MOs, and laser beam printers. It is suitable for a (LBP) polygon scanner motor or a small motor such as an electric device such as an axial fan.
[0002]
[Prior art]
The above various motors are required to have high speed, low cost, low noise, etc. in addition to high rotational accuracy. One of the components that determine these required performances is a bearing that supports the spindle of the motor. In recent years, as this type of bearing, a fluid bearing (particularly a dynamic pressure bearing) having characteristics excellent in the required performance has been used. Have been considered or actually used.
[0003]
For example, in a dynamic pressure bearing device incorporated in a spindle motor of a disk device such as an HDD, a radial bearing portion that rotatably supports a shaft member in a radial direction, and a thrust bearing portion that rotatably supports the shaft member in a thrust direction. And a dynamic pressure bearing having a groove (dynamic pressure groove) for generating dynamic pressure on at least a radial bearing portion is used. The dynamic pressure groove of the radial bearing portion is formed on one of the inner peripheral surface of the bearing sleeve and the outer peripheral surface of the shaft member.
[0004]
Normally, the bearing sleeve is fixed to the inner periphery of the housing by press-fitting, bonding, or the like, and a sealing member is provided at an opening of the housing to prevent the lubricating oil injected into the internal space of the housing from leaking outside. It is often fixed.
[0005]
[Problems to be solved by the invention]
The bearing device having the above-described configuration is composed of components such as a housing, a bearing sleeve, a shaft member, and a seal member, and in order to secure a high bearing performance required as information devices become more sophisticated, It is necessary to further improve the processing accuracy and assembly accuracy of parts. Further, with the trend of lowering the price of information equipment, the demand for cost reduction of this type of bearing device is becoming increasingly severe.
[0006]
An object of the present invention is to reduce the cost of this type of bearing device.
[0007]
Another object of the present invention is to improve the molding accuracy and functionality of the housing.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention includes a bearing sleeve that forms a radial bearing gap with the outer periphery of a shaft member to be supported, and a housing in which the bearing sleeve is fixed on the inner periphery. The housing is made of a resin product in a fluid bearing device in which the shaft member and the bearing sleeve are kept in non-contact in the radial direction by an oil film formed in the radial bearing gap when the sleeve is relatively rotated. Since resin housings can be formed by injection molding or other mold forming, they can be manufactured at a lower cost than metal housings made by machining such as turning, and compared to metal housings made by pressing or the like. Thus, relatively high accuracy can be secured.
[0009]
In the above configuration, the housing may be a resin product formed by welding a plurality of members.
[0010]
The resin housing can be formed, for example, by molding a resin using a bearing sleeve made of sintered metal or the like as an insert part. In this case, by forming the housing as an integrally molded product including the seal portion, the main body portion, and the bottom portion, the number of parts can be reduced, and the molding of the housing and the fixing of the bearing sleeve to the housing can be performed simultaneously. Therefore, it is advantageous in reducing the number of work steps. On the other hand, in this configuration, the housing has a complicated shape including the seal portion, the main body portion, and the bottom portion, and the shrinkage ratio of the resin between the contact portion and the non-contact portion with the bearing sleeve made of sintered metal or the like. In some cases, it is difficult to make the shrinkage ratio of the resin uniform because of the difference between them, and it is sometimes difficult to ensure the molding accuracy of the housing. In addition, despite the different functions required for each part of the housing such as the seal part, the main body part, and the bottom part, since each part is formed of the same resin composition, the required functions of each part are satisfied at a higher level. Can be difficult.
[0011]
By making the housing a resin product formed by welding a plurality of members, it becomes possible to mold each part of the housing with a resin composition having a material, a composition, a shape, etc. according to a required function of each part. . In addition, by combining housing parts having a simple shape, a housing having a complicated shape can be formed, and this part can be formed as a separate member according to the presence or absence of contact with the bearing sleeve. Therefore, the shrinkage ratio at the time of curing the resin can be made uniform in each part, and the housing can be made more precise.
[0012]
In this case, if the plurality of members are formed of different resin compositions, an optimal resin composition according to a required function can be selected and used, and the functionality of the housing can be improved. In this case, if the base materials (base resins) of different resin compositions are made common, it is possible to secure sufficient bonding strength and to enhance workability during welding.
[0013]
The housing includes a cylindrical main body having both ends opened, a bottom portion closing one end of the housing, and a seal portion provided at the other end of the housing and sealing a gap between the outer periphery of the shaft member. Can be provided. By providing the seal portion in the housing in this way, the number of parts can be reduced and the number of work steps can be reduced as compared with a case where a separately manufactured seal member is fitted and bonded to the inner periphery of the housing as in the related art. Further, cost reduction is achieved.
[0014]
The housing is formed by welding the main body, the seal portion, and the bottom as one member, and by welding these members to each other, or by integrally forming the main body and one of the bottom and the seal in advance. A member can be formed by welding it to the other.
[0015]
In any case, at least the main body can be molded with the bearing sleeve as an insert product. Thus, the operation of fixing the bearing sleeve can be performed simultaneously with the operation of forming the housing, and the number of operation steps can be reduced.
[0016]
Since the functions required for the main body, the seal, and the bottom are different from each other, it is desirable to select and use a resin composition for molding each part that meets the required functions.
[0017]
For example, the main body is required to have high strength so that accuracy can be maintained for a long time. Therefore, the main body is desirably formed of a resin composition in which a reinforcing material is blended with a thermoplastic resin as a base material.
[0018]
Further, at the bottom, it is required to reduce abrasion and frictional resistance at the time of contact with the shaft member. Therefore, it is desirable that the bottom is formed of a resin composition in which a solid lubricant is mixed with a thermoplastic resin as a base material.
[0019]
Further, it is desired that the seal portion reliably prevent oil leakage from inside the housing and intrusion of moisture and the like from the outside. Therefore, it is desirable that the seal portion is formed of a resin composition using a thermoplastic resin as a base material and having a contact angle to water of 80 ° or more.
[0020]
In a fluid bearing device in which a shaft end of a shaft member is supported in a thrust direction by a thrust bearing portion provided at the bottom of a housing, the pressure of the lubricating fluid increases around the thrust bearing portion, and the pressure difference between the lubricating fluid around the seal portion and the pressure difference. May occur. Due to this pressure difference, a local negative pressure is generated in the lubricating fluid in the internal space of the housing, which may cause bubbles to be generated in the lubricating fluid, resulting in leakage of the lubricating fluid and generation of vibration. is there. In addition, when the pressure of the lubricating fluid around the thrust bearing portion increases, the shaft member may be lifted. Such a problem can be solved by providing a communication groove for communicating the thrust bearing portion and the seal portion. That is, when the pressure of the lubricating fluid increases around the thrust bearing, the lubricating fluid flows from the periphery of the thrust bearing toward the periphery of the seal through the communication groove. Is kept constant.
[0021]
The communication groove is provided, for example, between a first radial groove provided between the bottom of the housing and one end surface of the bearing sleeve, and between the inner peripheral surface of the housing and the outer peripheral surface of the bearing sleeve. It can be constituted by an axial groove and a second radial groove provided between the inner surface of the seal portion and the other end surface of the bearing sleeve.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[0023]
FIG. 1 shows an example of a configuration of a spindle motor for information equipment incorporating a hydrodynamic bearing device 1 according to this embodiment. The spindle motor is used in a disk drive device such as an HDD, and includes a fluid bearing device 1 rotatably supporting a shaft member 2 in a non-contact manner, a disk hub 3 mounted on the shaft member 2, and a radial gap. And a motor stator 4 and a motor rotor 5 which are opposed to each other. The stator 4 is attached to the outer periphery of the casing 6, and the rotor 5 is attached to the inner periphery of the disk hub 3. The housing 7 of the hydrodynamic bearing device 1 is mounted on the inner periphery of the casing 6. The disk hub 3 holds one or more disks D such as magnetic disks. When the stator 4 is energized, the rotor 5 rotates by the exciting force between the stator 4 and the rotor 5, whereby the disk hub 3 and the shaft member 2 rotate integrally. As the fluid bearing device 1, a bearing device of any of the embodiments described below can be used.
[0024]
[First Embodiment]
FIG. 1 shows, as an example of a hydrodynamic bearing device, an embodiment of a hydrodynamic bearing device 1 that supports a shaft member by generating dynamic pressure of oil in a bearing gap by a groove (dynamic pressure groove) for generating dynamic pressure. Things.
[0025]
The dynamic pressure bearing device 1 includes a bottomed cylindrical housing 7 having one end opened and the other end closed, a cylindrical bearing sleeve 8, and a shaft member 2 as main components. In the following description, the opening side (seal side) of the housing 7 will be described as an upper side, and the closed side of the housing 7 will be described as a lower side.
[0026]
The shaft member 2 is formed of a metal material such as stainless steel. The shaft end (the lower end in the illustrated example) of the shaft member 2 is formed in a spherical shape, and the shaft end 2a is contact-supported by the bottom 7c of the housing to form a pivot type thrust bearing portion T. In the illustrated example, the shaft end 2a of the shaft member 2 is in direct contact with the inner bottom surface 7c1 of the housing bottom 7c. However, a thrust plate made of an appropriate material (such as a low friction material) is disposed on the housing bottom 7c. The shaft end 2a can be brought into sliding contact with this.
[0027]
The bearing sleeve 8 is disposed at a predetermined position on the inner peripheral surface of the housing 7, more specifically, on the inner peripheral surface 7b1 of the main body 7b. The bearing sleeve 8 is formed of, for example, a porous body made of a sintered metal, particularly a sintered metal mainly containing copper. The internal pores (pores of a porous structure) of the bearing sleeve 8 made of this sintered metal are impregnated with a lubricating fluid, for example, lubricating oil. A first radial bearing portion R1 and a second radial bearing portion R2 are provided between the inner peripheral surface 8a of the bearing sleeve 8 and the outer peripheral surface of the shaft member 2 so as to be separated in the axial direction.
[0028]
On the inner peripheral surface 8a of the bearing sleeve 8, two regions serving as radial bearing surfaces of a first radial bearing portion R1 and a second radial bearing portion R2 are provided axially separated from each other. For example, herringbone-shaped dynamic pressure grooves are respectively formed. The dynamic pressure groove may have a spiral shape, an axial groove shape, or the like. A groove 8 e for identifying the direction of the bearing sleeve 8 is formed in an annular shape on the upper end surface 8 b of the bearing sleeve 8.
[0029]
The housing 7 is formed of a resin composition, and is formed, for example, by injection molding a resin using the bearing sleeve 8 made of a sintered metal as an insert part. The housing 7 includes a cylindrical main body 7b, a seal 7a extending radially inward from an upper end of the main body 7b, and a bottom 7c for closing a lower end of the main body 7b. In the illustrated housing 7, the main body 7b and the bottom 7c are integrally formed as a single member, which is welded to the seal 7a. Specifically, after the main body portion 7b and the bottom portion 7c are integrally molded with the bearing sleeve 8 as an insert product, a separately manufactured seal portion 7a is fitted to the inner periphery of the main body portion 7b, and ultrasonic welding or the like is performed. Are welded together by the above welding means.
[0030]
The inner peripheral surface 7a1 of the seal portion 7a and the inner peripheral surface 7b1 of the main body portion 7b extend straight in the axial direction, and the inner peripheral surface 7a1 of the seal portion 7a has a tapered outer peripheral surface formed on the shaft member 2. They face each other via a tapered seal space S having a predetermined width. In the housing 7, the inner surface 7a2 of the seal portion 7a and the upper end surface 8b of the bearing sleeve 8, the inner peripheral surface 7b1 of the main body 7b and the outer peripheral surface of the bearing sleeve 8, the inner surface 7c1 of the bottom portion 7c and the lower end surface of the bearing sleeve 8 are provided. 8c are in close contact with each other.
[0031]
Note that the chamfered portion 8d formed on the inner periphery of the upper end surface 8b of the bearing sleeve 8 is not covered with the resin. Therefore, if the groove 8e is formed in the chamfered portion 8d in, for example, an annular shape, it is possible to determine the direction of the bearing sleeve 8 from outside even after the housing 7 is formed. In addition, even when the groove 8e is formed in the upper end surface 8b, the same effect can be obtained by forming at least the seal portion 7a of the housing 7 with a transparent resin.
[0032]
The shaft member 2 is inserted into the inner peripheral surface 8a of the bearing sleeve 8, and makes the spherical portion 2a contact the inner end surface 7c1 of the bottom portion 7c of the housing. The internal space of the housing 7 sealed by the seal portion 7a is filled with lubricating oil, including the internal pores of the bearing sleeve 8. The oil level of the lubricating oil is maintained in the seal space S.
[0033]
When the shaft member 2 and the bearing sleeve 8 rotate relative to each other (in this embodiment, when the shaft member 2 rotates), the regions (two upper and lower regions) of the inner peripheral surface 8a of the bearing sleeve 8 that become radial bearing surfaces are respectively It faces the outer peripheral surface of the shaft member 2 via the radial bearing gap. Then, with the rotation of the shaft member, an oil film of the lubricating oil is formed in the radial bearing gap, and the shaft member 2 is rotatably supported in the radial direction by the dynamic pressure. Thus, a first radial bearing portion R1 and a second radial bearing portion R2 that rotatably support the shaft member 2 in the radial direction in a non-contact manner are configured. On the other hand, the shaft member 2 is rotatably supported in a thrust direction by a pivot type thrust bearing portion T.
[0034]
As described above, according to the present invention, a cup-shaped composite member composed of the main body portion 7b and the bottom portion 7c is molded in advance as one member, and then the seal portion 7a is welded to this member as another member. , A housing 7. Thereby, since the shape of each member is simplified, each part 7a to 7c of the housing 7 can be molded with high precision, and the precision of the housing 7 can be improved. In addition, since the seal portion 7a can be formed of a resin composition having characteristics suitable for its function (seal function), the sealability is enhanced, and oil leaks from the housing 7 and foreign matters (water). ) Can be stably prevented for a long period of time.
[0035]
Examples of the resin composition having excellent sealing properties include a resin composition having non-adhesiveness. This is a resin composition having a contact angle with water of 80 ° or more. A resin composition satisfying this condition is rich in not only water repellency but also oil repellency. It is possible to reliably prevent dispensing for a long period of time. Examples of the resin composition include a molten fluorine resin such as PFA and a polyolefin resin such as PE. In addition, non-adhesive materials having similar properties can be obtained by blending any one (or two or more) of PTFE, the above-mentioned molten fluororesin, and the above-mentioned polyolefin resin into a thermoplastic resin (particularly an engineering plastic) as a base material. The resin composition can be obtained. In this case, as the base material, a polyamide resin, PPS (polyphenylene sulfide resin), LCP (liquid crystal polymer resin), or the like can be used.
[0036]
[Second embodiment]
In the second embodiment shown in FIG. 3, unlike the first embodiment, a cup-shaped composite member including a seal portion 7a and a main body portion 7b is integrally formed as one member in advance. After the insert molding, the housing 7 is integrally formed by welding another member (bottom part 7c) separately manufactured to the opening end surface of the main body part 7b by means such as ultrasonic welding.
[0037]
In this case, the bottom 7c can be formed of a resin composition having excellent wear resistance and self-lubricating properties, thereby reducing the friction at the thrust bearing portion T, and reducing the abrasion of the bottom 7c. Torque can be achieved. As the resin composition, a resin in which a solid lubricant such as PTFE, graphite, molybdenum disulfide or the like is blended with a thermoplastic resin (in particular, engineering plastic) can be considered. In this case, it is desirable to use PPS, LCP or the like as the thermoplastic resin.
[0038]
[Third embodiment]
FIG. 4 shows an embodiment in which the housing 7 is integrally formed by molding the seal portion 7a, the main body portion 7b, and the bottom portion 7c of the housing 7 as one member, and welding them together. After the main body portion 7b is insert-molded using the bearing sleeve 8 as an insert part, the seal portion 7a and the bottom portion 7c separately manufactured are welded to the end surfaces of the openings at both ends thereof by ultrasonic welding or the like to obtain the housing 7 in the illustrated example. Can be
[0039]
In this case, the main body 7b can be formed of a resin composition having a high dimensional accuracy, whereby the accuracy of the housing 7 (particularly, the main body 7b) is increased, and the deformation of the bearing sleeve 8 based on the error of the housing 7 is prevented. And the precision of the dynamic pressure groove can be maintained. As the resin composition, a reinforcing material, for example, a fibrous reinforcing material (glass fiber or the like), a whisker-like reinforcing material (potassium titanate or the like), or a flaky reinforcing material (mica or the like) is used as a thermoplastic resin (particularly an engineering plastic). Can be considered. As the thermoplastic resin, it is desirable to use PPS, LCP or the like as in the first embodiment.
[0040]
[Fourth embodiment]
In the fourth embodiment shown in FIG. 5, the seal portion 7a and the bottom portion 7c are welded to both end surfaces of the main body 7b in the third embodiment (see FIG. 4). Shows a case where the seal portion 7a and the bottom portion 7c are welded. The other points are the same as those of the third embodiment, and the duplicate description will be omitted.
[0041]
[Fifth Embodiment]
The fifth embodiment shown in FIG. 6 can be said to be a composite type of the third embodiment and the fourth embodiment. Steps 7a3, 7c3, 7b3, 7a3, 7c3, and 7b 7b4, the step 7a3 of the seal 7a is brought into close contact with the step 7b3 at the upper end of the main body, and the step 7c3 of the bottom 7c is brought into close contact with the step 7b4 at the lower end of the main body. These are welded to each other. In the illustrated example, the steps are fitted to each other at both ends of the main body 7b. However, the fitting state may be the same at any one end as in the third and fourth embodiments.
[0042]
When the respective parts 7a, 7b, 7c of the housing are welded in this way, strong welding can be performed by forming the members to be welded with a resin composition having a common base resin, and at the time of welding. Workability can also be improved. For example, when a resin composition containing LCP as a base material is used for the main body 7b, the seal portion 7a and the bottom 7c are also formed of a resin composition containing LCP as a base material.
[0043]
Since LCP has a liquid crystal reinforcing effect (self-reinforcing) and a friction reducing effect after curing, LCP itself has abrasion resistance and high precision without blending a reinforcing material or a solid lubricant. Has excellent properties. Therefore, each housing part 7a-7c can also be formed only with LCP, and it becomes also possible to shape the housing 7 with a single kind of resin composition. Further, since the LCP has a low outgassing property, if the housing 7 is formed of the LCP, it becomes more suitable as a spindle motor bearing for an HDD device which does not want to generate such outgas.
[0044]
[Sixth embodiment]
In the sixth embodiment shown in FIG. 7, the thrust bearing portion T and the seal space S of the seal portion 7a are communicated by the communication groove 10. In this embodiment, the communication groove 10 includes a first radial groove 10 a formed on the lower end surface 8 c of the bearing sleeve 8, an axial groove 10 b formed on the outer peripheral surface of the bearing sleeve 8, and an upper end surface 8 b of the bearing sleeve 8. And the second radial groove 10c formed at the second position. The first radial groove 10a is formed on the inner bottom surface 7c1 of the bottom 7c of the housing 7, the axial groove 10b is formed on the inner peripheral surface 7b1 of the main body 7b of the housing 7, and the second radial groove 10c is formed on the inside of the seal portion 7a. It may be formed on the side surface 7a2.
[0045]
The housing 7 is formed of, for example, a resin composition according to the first embodiment shown in FIG. 2, but in this embodiment, the main body 7b and the bottom 7c are integrally formed as one member, and the main body 7 is formed. After fixing the bearing sleeve 8 to the inner periphery of the main body 7b by appropriate means such as bonding, press-fitting, and ultrasonic welding, a separately manufactured seal portion 7a is fitted to the inner periphery of the main body 7b, and ultrasonic welding or the like is performed. Welding means. This is because, similarly to the first embodiment, when the bearing sleeve 8 is used as an insert part and the housing 7 is injection-molded with resin, the first radial groove 10a and the axial groove 10b formed in the bearing sleeve 8 are melted during molding. This is because it is buried by the resin.
[0046]
When the pressure of the lubricating oil increases around the thrust bearing portion T during the rotation of the shaft member 2, the flow of the lubricating oil from the periphery of the thrust bearing portion T toward the periphery of the seal space S occurs through the communication groove 10. The pressure of the lubricating oil around the thrust bearing portion T and the periphery of the seal space S is kept constant. Therefore, the generation of bubbles due to the generation of a local negative pressure in the lubricating oil, the leakage of the lubricating fluid, the occurrence of vibrations, and the like due to this are prevented. Further, the lifting of the shaft member 2 due to an increase in the pressure of the lubricating oil around the thrust bearing portion T is also prevented.
[0047]
The present invention is applicable to all hydrodynamic bearing devices in which the housing 7 is formed of a resin composition, and the shape of the housing and the structure of the bearing are not limited to those shown in the drawings. For example, the present invention can be similarly applied to an apparatus in which the thrust bearing portion T is constituted by a dynamic pressure bearing that supports the thrust bearing portion T in a non-contact manner by a fluid dynamic pressure generated in the thrust bearing gap. Further, instead of molding the bearing sleeve 8 with the housing 7 as in the sixth embodiment, the bearing sleeve 8 is bonded or press-fitted to the inner periphery of a separately formed bottomed cylindrical resin housing 7. The present invention can be similarly applied to the case of fixing with.
[0048]
Further, in each of the above embodiments, the case where a dynamic pressure bearing having a dynamic pressure groove as dynamic pressure generating means is used as the radial bearing portions R1 and R2 is described. The present invention can be similarly applied to the case where a perfect circular bearing having no dynamic pressure groove and a radial bearing surface having a perfect circular shape is used as R2.
[0049]
【The invention's effect】
As described above, according to the present invention, since the housing is made of a resin product, the cost of this type of hydrodynamic bearing device can be reduced. Also, relatively high molding accuracy of the housing can be ensured.
[0050]
Further, according to the present invention, each part of the housing can be molded with a resin composition corresponding to a required function of each part, so that the functionality of the housing can be enhanced. In addition, by combining housing parts having a simple shape, a housing having a complicated shape can be molded, and since each part can be formed as a separate member depending on whether or not there is contact with a bearing sleeve, resin curing can be performed. The shrinkage at the time can be made uniform in each part, and the housing can be made more precise.
[0051]
Further, in a fluid bearing device having a configuration in which a shaft end of a shaft member is supported in a thrust direction by a thrust bearing provided at a bottom portion of a housing, a communication groove for communicating the thrust bearing and a seal is provided, so that lubricating oil is provided. This prevents the occurrence of a local negative pressure, thereby preventing the generation of air bubbles due to the generation of the negative pressure, the occurrence of leakage of the lubricating fluid and the occurrence of vibration due to this. In addition, it is possible to prevent the shaft member from rising due to an increase in the pressure of the lubricating oil around the thrust bearing portion.
[Brief description of the drawings]
FIG. 1 is a sectional view of a spindle motor for information equipment using a hydrodynamic bearing device according to the present invention.
FIG. 2 is a cross-sectional view showing one embodiment of the hydrodynamic bearing device according to the present invention.
FIG. 3 is a sectional view showing a second embodiment of the present invention.
FIG. 4 is a sectional view showing a third embodiment of the present invention.
FIG. 5 is a sectional view showing a fourth embodiment of the present invention.
FIG. 6 is a sectional view showing a fifth embodiment of the present invention.
FIG. 7 is a sectional view showing a sixth embodiment of the present invention.
[Explanation of symbols]
1 Fluid bearing device (dynamic bearing device)
2 Shaft member 2a Spherical part 7 Housing 7a Seal part 7b Main part 7c Bottom part 8 Bearing sleeve 10 Communication groove 10a First radial groove 10b Axial groove 10c Second radial groove R1 Radial bearing part R2 Radial bearing part T Thrust bearing part

Claims (13)

A bearing sleeve that forms a radial bearing gap with the outer periphery of the shaft member to be supported, and a housing with the bearing sleeve fixed to the inner periphery are formed in the radial bearing gap when the shaft member and the bearing sleeve rotate relative to each other. In a fluid bearing device that holds a shaft member and a bearing sleeve in a radial direction in a non-contact manner with an oil film,
A fluid bearing device wherein the housing is made of a resin product. 2. The hydrodynamic bearing device according to claim 1, wherein the housing is a resin product formed by welding a plurality of members. 3. The hydrodynamic bearing device according to claim 2, wherein the plurality of members are formed of different resin compositions. 4. The hydrodynamic bearing device according to claim 3, wherein the base materials of the different resin compositions are common. The housing has a cylindrical main body part having both ends opened, a bottom part closing one end side of the housing, and a seal part provided on the other end side of the housing and sealing a gap between the outer periphery of the shaft member. The hydrodynamic bearing device according to claim 1. The hydrodynamic bearing device according to claim 5, wherein the main body, the seal, and the bottom are formed as one member, and are welded to each other. 6. The hydrodynamic bearing device according to claim 5, wherein the main body, one of the bottom and the seal are integrally formed in advance to form one member, which is welded to the other. The hydrodynamic bearing device according to any one of claims 5 to 7, wherein at least the main body is molded using the bearing sleeve as an insert product. 6. The hydrodynamic bearing device according to claim 5, wherein the main body is formed of a resin composition obtained by mixing a reinforcing material with a thermoplastic resin as a base material. The fluid bearing device according to claim 5, wherein the bottom portion is formed of a resin composition in which a solid lubricant is mixed with a thermoplastic resin as a base material. 6. The hydrodynamic bearing device according to claim 5, wherein the seal portion is formed of a resin composition using a thermoplastic resin as a base material and having a contact angle with water of 80 ° or more. The housing has a cylindrical main body, a bottom portion closing one end of the housing, and a seal portion provided on the other end side of the housing and sealing a gap between the outer periphery of the shaft member. 2. The hydrodynamic bearing device according to claim 1, wherein a thrust bearing portion for supporting a shaft end of the shaft member in a thrust direction is provided at a bottom portion, wherein a communication groove for communicating the thrust bearing portion and the seal portion is provided. Hydrodynamic bearing device characterized by the following. A first radial groove provided between the bottom of the housing and one end surface of the bearing sleeve; an axial groove provided between an inner peripheral surface of the housing and an outer peripheral surface of the bearing sleeve; 13. The hydrodynamic bearing device according to claim 12, comprising a second radial groove provided between the inner surface of the seal portion and the other end surface of the bearing sleeve.

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