Abstract: A protrusion (7b3) directed axially downwards is provided at a bottom portion (7b) of a housing (7), and an outer peripheral surface (7b31) of the protrusion (7b3) is fixed to an inner peripheral surface (6a) of a bracket (6). When a thrust load is applied to the bottom portion (7b) of the housing (7), a part of the load is supported by the bracket (6) via the protrusion (7b3). Thus, a strength of a boundary portion (P) between a side portion (7a) and the bottom portion (7b) of the housing (7) increases, making it possible to prevent rupture of the boundary portion (P) due to an excessive thrust load. On the other hand, a wall thickness of the bottom portion (7b) can be made invariable, so it is possible to suppress deformation through molding shrinkage of a thrust bearing surface formed on an inner end surface (7b1) of the bottom portion (7b).

Abstract: Provided is a fluid dynamic bearing device which has excellent moment rigidity and an improved working efficiency in assembling and parts control, and in which a bearing sleeve can be easily manufactured. A plurality of bearing sleeves are axially disposed in the fluid dynamic bearing device. The bearing sleeves (3, 4) are formed with different axial lengths from each other.

Abstract: A fluid dynamic bearing device includes a bearing sleeve including a radial bearing surface, a shaft member to be inserted to an inner circumference of the bearing member, and a radial bearing part for non-contact supporting the shaft member in a radial direction by a dynamic pressure action of a fluid generated in a radial bearing gap between the radial bearing surface of the bearing member and an outer circumferential surface of the shaft member. Additionally, a plurality of bearing sleeves are axially arranged, and each bearing sleeve is formed having different axial length with respect to one another.

Abstract: Peeling-off of an oil-repellent film can be reliably prevented. A fluid dynamic bearing device (1) includes a shaft member (2) and first and second flange portions (9, 10) serving as seal portions fixed to the shaft member (2). On outer peripheral sides of the first and second flange portions (9, 10), a first seal space (S1) and a second seal space (S2) are formed, respectively. Oil-repellent films (11) are provided on end surfaces of the first flange portion (9) and the second flange portion (10) separately from a pressure-receiving surface (12) subjected to pressure at a time of assembly, the end surfaces being exposed to external air.

Abstract: Provided is a bearing capable of satisfying demands for cost reduction and further quietness, and stably maintaining high support accuracy. A sliding bearing (4) includes an inner member (5) having a mounting surface (9) with respect to a rotary shaft (2), and an outer member (6) being arranged on a radially outer side of the inner member (5). A radial bearing gap is formed between an outer peripheral surface (5a1) of the inner member (5) and an inner peripheral surface (7a1) of the outer member (6), and a lubricating oil is interposed in the radial bearing gap. Further, between the inner member (5) and the outer member (6), sealing gaps (S, S) for maintaining an oil level of the lubricating oil on both axial sides of the radial bearing gap are formed. At least a part of the mounting surface (9) of the inner member (5) is made of a metal.

Abstract: A fluid dynamic bearing device includes a housing injection molded with a bearing sleeve as an insert. Accordingly, the molding of the housing and the assembly of the housing and the bearing sleeve can be performed in a single step. In addition to this, by simply increasing the die precisions the housing and the bearing sleeve can be fixed easily with high precision. Since the housing is opened at both ends, it is possible to sandwich the bearing sleeve, and accordingly, the bearing sleeve can be accurately positioned inside the dies with reliability.

Abstract: An outer peripheral surface (8d) of a bearing sleeve (8) is formed on a radially inside with respect to a first dynamic pressure generation portion (B1). In this case, it is possible to reduce a thickness of the bearing sleeve (8) while securing a first thrust dynamic pressure generating portion (B1) which has a thrust load capacity equivalent to that in a conventional case where a thrust dynamic pressure generating portion is formed in an end surface of the bearing sleeve. Accordingly, it is possible to reduce the thickness of the bearing sleeve (8) without sacrificing a bearing performance in a thrust direction. With this structure, a total amount of a lubricating oil sealed in a bearing device can be reduced, thereby reducing a capacity of a buffering function so as to downsize a sealing portion (9), and by extension, downsizing a fluid dynamic bearing device (1).

Abstract: To provide a fluid dynamic pressure bearing device that achieves high rigidity against moment without degradation in assembly precision and bearing performance, bearing sleeves are arranged in an axial direction and coaxiality of radial bearing surfaces formed on inner peripheral surfaces of the bearing sleeves is set to 3 ?m or less. This secures width precision between the radial bearing gaps to prevent a degradation in bearing performance and a failure such as wear etc. caused by contact between a shaft member and the bearing sleeves. Further, a first radial bearing surface and a second radial bearing surface are provided on at least one sleeve, and this allows a sleeve assembly constructed from the bearing sleeves to be supported at least three positions in the axial direction in a process of assembling the sleeve assembly.

Abstract: A fluid dynamic bearing unit is provided which has a high load capacity against a moment load, whose bearing sleeves can be manufactured and fixed easily, and which can provide a required fixing power. The bearing sleeve is inserted into an inner periphery of a housing, and its bottom end is fixed to the top end of a spacer part with an adhesive. Another bearing sleeve is inserted into another part of the inner periphery of the housing, and its top end is fixed to the bottom end of the spacer part with an adhesive.

Abstract: The fluid dynamic bearing device includes a housing, two bearing sleeves fixed to the housing at positions axially spaced apart from each other, and a shaft member inserted along inner peripheries of the bearing sleeves. The housing includes a spacer portion protruding further radially inwardly than inner peripheral surfaces to which the bearing sleeves are fixed. An axial fluid path is formed in the spacer portion, and the axial fluid path communicates to flow paths formed by axial grooves of the bearing sleeves.

Abstract: To increase fixation strength of a bearing sleeve with respect to a bottomed cylindrical housing, a fluid dynamic bearing device (1) is provided with a bottomed cylindrical housing (7), a bearing sleeve (8) fixed to an inner periphery thereof, and a shaft member (2) inserted along an inner periphery of the bearing sleeve (8). An adhesive pool (11) is provided between an inner peripheral surface (7a2) of a smaller diameter portion (7a) of the housing (7) and an outer peripheral surface (8d) of the bearing sleeve (8), which are opposed to each other. Further, an inner peripheral chamfer (7f) continuous with the adhesive pool (11) is provided on an inner peripheral portion of the housing (7), and a first tapered space (12) formed between the inner peripheral chamfer (7f) and the bearing sleeve (8) is sealed with an adhesive (13).

Abstract: A double-row self-aligning roller bearing includes left and right rows of rollers, arranged between an inner race and an outer race. A raceway surface of the outer race represents a spherical shape and the rollers have an outer peripheral surface following the shape of the raceway surface of the outer race. The rollers of the left and right roller rows have respective lengths different from each other. Also, the left and right roller rows have respective contact angles different from each other.

Abstract: A molding pin (23) is formed in a sectional shape of being held in contact at two points (contact points are denoted by P?) with an imaginary cylindrical surface (C?). As a result, an undercut of a fixation hole (21b1) is reduced or eliminated, and hence it becomes easier to process a die. Moreover, a corner portion (21d) between a cylindrical surface (21c) and the fixation hole (21b1) becomes obtuse, and hence the die becomes less liable to deform and break. Therefore, manufacturing cost of the die can be reduced, and hence cost reduction of the bearing device can be achieved.

Abstract: To provide a fluid dynamic pressure bearing device that achieves high rigidity against moment without degradation in assembly precision and bearing performance, bearing sleeves are arranged in an axial direction and coaxiality of radial bearing surfaces formed on inner peripheral surfaces of the bearing sleeves is set to 3 ?m or less. This secures width precision between the radial bearing gaps to prevent a degradation in bearing performance and a failure such as wear etc. caused by contact between a shaft member and the bearing sleeves. Further, a first radial bearing surface and a second radial bearing surface are provided on at least one sleeve, and this allows a sleeve assembly constructed from the bearing sleeves to be supported at least three positions in the axial direction in a process of assembling the sleeve assembly.

Abstract: A protrusion (7b3) directed axially downwards is provided at a bottom portion (7b) of a housing (7), and an outer peripheral surface (7b31) of the protrusion (7b3) is fixed to an inner peripheral surface (6a) of a bracket (6). When a thrust load is applied to the bottom portion (7b) of the housing (7), a part of the load is supported by the bracket (6) via the protrusion (7b3). Thus, a strength of a boundary portion (P) between a side portion (7a) and the bottom portion (7b) of the housing (7) increases, making it possible to prevent rupture of the boundary portion (P) due to an excessive thrust load. On the other hand, a wall thickness of the bottom portion (7b) can be made invariable, so it is possible to suppress deformation through molding shrinkage of a thrust bearing surface formed on an inner end surface (7b1) of the bottom portion (7b).

Abstract: Provided is a fluid dynamic bearing device in which an assembly of a bearing sleeve to a housing is facilitated and which has excellent moment rigidity. A fluid dynamic bearing device (1) includes radial bearing parts (R1 and R2) and thrust bearing parts (T1 and T2). Thrust bearing surfaces (C and D) are respectively provided to first and second step surfaces (2d and 2e) of a housing (2), and the thrust bearing parts (T1 and T2) are respectively formed between the thrust bearing surfaces (C and D) and end surfaces (6b and 7b) of seal members (6 and 7) provided while protruding to an outer diameter side of a shaft member (5).

Abstract: A dynamic bearing device is provided, which can prevent abrasion powder generated when a sealing member is pushed into an inner circumference of a housing from entering the housing. A sealing member is inserted into an inner circumference of an opening of a housing with an adhesive interposed therebetween The adhesive moving forward in a pushing direction of the sealing member is retained by a capillary action in a lower tapered space between an outer circumference of the sealing member and the inner circumference of the housing. Abrasion powder is captured by the adhesive in the tapered space so as to be confined in the adhesive as a result of the setting of the adhesive.

Abstract: Easy and precise setting of a predetermined thrust bearing gap is made possible. An axial gap 13 having a dimension that is equal to the sum of two thrust bearing gaps is first provided between the flange part 2b of the shaft member 2 and the bearing member or bearing sleeve 8. The shaft member 2 and the bearing sleeve 8 are accommodated inside the housing 7 with this gap dimension 8 being kept, and the bearing sleeve 8 is secured to the housing 7.

Abstract: A dynamic bearing device is provided, which can prevent abrasion powder generated when a sealing member is pushed into an inner circumference of a housing from entering the housing. A sealing member is inserted into an inner circumference of an opening of a housing with an adhesive interposed therebetween The adhesive moving forward in a pushing direction of the sealing member is retained by a capillary action in a lower tapered space between an outer circumference of the sealing member and the inner circumference of the housing. Abrasion powder is captured by the adhesive in the tapered space so as to be confined in the adhesive as a result of the setting of the adhesive.

Abstract: Peeling-off of an oil-repellent film can be reliably prevented. A fluid dynamic bearing device (1) includes a shaft member (2) and first and second flange portions (9, 10) serving as seal portions fixed to the shaft member (2). On outer peripheral sides of the first and second flange portions (9, 10), a first seal space (S1) and a second seal space (S2) are formed, respectively. Oil-repellent films (11) are provided on end surfaces of the first flange portion (9) and the second flange portion (10) separately from a pressure-receiving surface (12) subjected to pressure at a time of assembly, the end surfaces being exposed to external air.