JP2009041597A - Bearing unit, motor having it, and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing unit capable of holding the rotating performance by preventing a thrust bearing from rotation, dislocation, etc. and establishing a favorable cost performance by enhancing the use efficiency of the material for thrust bearing. <P>SOLUTION: Arrangement according to the invention comprises a shaft 31, a radial bearing 33 to make supporting in the circumferential direction of the shaft 31, and the thrust bearing 34 to support the shaft 31 at its one end about the thrust direction, and a housing 35 fitted internally with the radial bearing 33 and the thrust bearing 34, wherein the thrust bearing 34 is shaped polygonal when projected on a plane approximately perpendicularly intersecting the thrust direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bearing unit that rotatably supports a rotating shaft or a rotating body that rotatably supports a shaft, a motor having the bearing unit, and an electronic apparatus.

  Conventionally, a bearing unit that rotatably supports a rotating shaft is known. The bearing unit includes a shaft, a radial bearing that supports the shaft in the circumferential direction, a thrust bearing that supports the shaft in the axial direction, and a housing in which the radial bearing and the thrust bearing are disposed.

  Such a bearing unit rotatably supports a rotating shaft by a radial bearing and a thrust bearing.

  By the way, the thrust bearing that constitutes such a bearing unit is generally formed as a pivot bearing that supports the tip of the rotating shaft formed in an arc shape or a tapered tip at a point. The thrust bearing 134 is formed by punching a sheet material such as a polymer into a circular shape as shown in FIG.

  In the bearing unit configured as described above, if the thrust bearing rotates with the shaft, shifts in position or moves within the housing, the rotational performance is adversely affected by shaft blurring or the like. Problems may occur.

  Further, when cutting out from a sheet-like material such as a polymer, an extra portion S is generated as shown in FIG. 14, and the use efficiency of the material is not sufficient, and it is high when an expensive sheet-like material is used. It was a factor of cost.

JP 2005-226780 A

  SUMMARY OF THE INVENTION An object of the present invention is to prevent a thrust bearing from rotating, misaligned, etc. to maintain rotational performance, and to increase the use efficiency of the material of the thrust bearing, which is advantageous in terms of cost, a motor having the bearing unit, and an electronic device Is to provide.

  To achieve this object, a bearing unit according to the present invention includes a shaft, a radial bearing that supports the shaft in the circumferential direction, a thrust bearing that supports one end of the shaft in the thrust direction, and the radial bearing. And a housing in which the thrust bearing is disposed, and the thrust bearing has a polygonal shape in a plane substantially perpendicular to the thrust direction.

  The motor according to the present invention proposed to achieve the above-described object is a motor having a bearing unit that rotatably supports the rotor with respect to the stator, and as described above, the bearing unit used for this motor. It uses something.

  An electronic device according to the present invention proposed to achieve the above-described object is an electronic device including a motor having a bearing unit that rotatably supports a rotor with respect to a stator, and a bearing used for the electronic device. The unit described above is used.

  In the present invention, the shape of the thrust bearing that supports one end in the thrust direction of the shaft is a polygonal shape on the surface substantially orthogonal to the thrust direction, so that the rotation and displacement of the thrust bearing can be reliably prevented and rotated. The cost can be reduced by preventing the deterioration of the performance and increasing the utilization efficiency of the material of the thrust bearing.

  An information processing apparatus to which the present invention is applied will be described below with reference to the drawings.

  As shown in FIG. 1, an information processing apparatus to which the present invention is applied is a notebook personal computer, and includes a display unit 2 that displays information processing results and the like, and an information processing unit that performs arithmetic processing of various types of information. And a built-in computer main body 3. A keyboard 5 for inputting an operation command of the computer 1 or inputting various kinds of information is provided on the upper surface side of the computer main body 3, and a heat dissipation device 4 is provided therein. The heat radiating device 4 is a cooling device that radiates heat generated from an information processing circuit such as a CPU or a disk device disposed inside the computer main body 3 to the outside of the computer main body 3 and cools the inside of the computer main body 3. Also works.

  As shown in FIG. 2, the heat radiating device 4 built in the computer main body 3 is accommodated in a housing 6 constituting the computer main body. As shown in FIG. 3, the heat dissipation device 4 includes a metal base 7, a motor 10 attached to the base 7, a fan 8 that is rotated by the motor 10, and a fan case 9 that houses the fan 8. And a heat sink 11.

  As shown in FIG. 3, the base 7 is formed in a substantially L shape. A heating element 12 that generates heat by being energized and driven like a CPU (central processing unit) is attached to one surface 7a on one end side of the base 7 formed in a substantially L shape. The heat generating element 12 is attached to the one surface 7a side of the base 7 through a heat transfer seal 12a.

  A motor 10 is attached to a substantially central portion on the one surface 7 a side of the base 7, and a fan case 9 that houses a fan 8 that is rotated by the motor 10 is attached. The fan case 9 is provided with a circular air inlet 13 that opens a position corresponding to the central portion of the fan 8 rotated by the motor 10. An opening 14 is provided at a position facing the air inlet 13 provided in the fan case 9 on the bottom side of the housing 6 so as to communicate with the air inlet 13. Further, the fan case 9 is provided with an exhaust port 15 for exhausting air sucked from the intake port 13 to the outside.

  A heat sink 11 is fixed to one surface 7 a on the other end side of the base 7. The heat sink 11 is a corrugated or fin-shaped heat sink, and is made of a metal excellent in heat dissipation, such as aluminum. The base 7 and the fan case 9 are also preferably made of aluminum or iron, which is a metal with excellent heat dissipation.

  A heat generating element 12 is attached, and a heat sink 4 that dissipates heat generated from the heat generating element 12 and a base 7 to which the heat sink 11 is attached are inserted into a plurality of screws that are used when being attached in the housing 6. A mounting hole 7b is provided. The base 7 is mounted in the housing 6 by fixing a fixing screw inserted into the mounting hole 7b to a boss 16 provided inside the housing 6 as shown in FIG.

  When the base 7 is mounted in the housing 6, the heat sink 11 is disposed at a position facing the through hole 17 provided on the side surface of the housing 6 as shown in FIGS. 2 and 3.

  When the motor 10 is driven and the fan 8 is rotated by the motor 10 in the direction of the arrow R1 in FIG. 3, the heat dissipation device 4 configured as described above is provided outside the device via the opening 14 provided in the housing 6. Air is sucked in the direction of arrow D1 in FIGS. 2 and 3 and further sucked into the fan case 9 through the air inlet 13. The air sucked into the fan case 9 by the rotation of the fan 8 circulates in the direction of the arrow D2 in FIGS. 2 and 3, and further circulates in the direction of the arrow D3 in FIG. The air is exhausted to the outside of the housing 6 through 17.

  By the way, the heat generated by driving the heat generating element 12 attached to the base 7 is transmitted to the heat sink 11 attached to the base 7 through the base 7 formed of a metal having excellent heat dissipation. At this time, the air sucked from the outside of the housing 6 when the fan 8 of the heat radiating device 4 is rotated by the motor 10 circulates in the plurality of fins of the heat sink 11, so that the heat transmitted to the heat sink 11 is Heat is radiated to the outside of the housing 6 through the through hole 17.

  As shown in FIG. 4, the motor 10 to which the present invention is used for the heat radiating device includes a rotor 18 and a stator 19.

  The stator 19 is integrally provided on the upper surface plate 9 a side of the fan case 9 that houses the fan 8 rotated by the motor 10 together with the motor 10. The stator 19 includes a stator yoke 20, a bearing unit 30 to which the present invention is applied, a coil 21, and a core 22 around which the coil 21 is wound. The stator yoke 20 may be formed integrally with the upper surface portion 9a of the fan case 9, that is, may be constituted by a part of the fan case 9, or may be formed separately. The stator yoke 20 is made of, for example, iron. The bearing unit 30 is fixed by press-fitting or bonding into a cylindrically formed holder 23 at the center of the stator yoke 20, and further by bonding together with press-fitting.

  The holder 23 into which the bearing unit 30 is press-fitted is formed in a cylindrical shape integrally with the stator yoke 20.

  As shown in FIG. 4, a core 22 around which a coil 21 to which a drive current is supplied is attached is attached to the outer peripheral portion of a holder 23 formed integrally with the stator yoke 20.

  The rotor 18 that constitutes the motor 10 together with the stator 19 is attached to a rotating shaft 31 that is rotatably supported by the bearing unit 30, and rotates integrally with the rotating shaft 31. The rotor 18 includes a rotor yoke 24 and a fan 8 having a plurality of blades 25 that rotate integrally with the rotor yoke 24. The blades 25 of the fan 8 are formed integrally with the rotor yoke 24 by outsert molding on the outer peripheral surface of the rotor yoke 24.

  A ring-shaped rotor magnet 26 is provided on the inner peripheral surface of the cylindrical portion 24 a of the rotor yoke 24 so as to face the coil 21 of the stator 19. The magnet 26 is a plastic magnet in which S and N poles are alternately magnetized in the circumferential direction, and is fixed to the inner peripheral surface of the rotor yoke 24 with an adhesive.

  The rotor yoke 24 is rotated by press-fitting a boss portion 27 provided with a through-hole 27a provided in the central portion of the flat plate portion 24b into an attachment portion 32 provided on the distal end side of the rotating shaft 31 supported by the bearing unit 30. Attached to the shaft 31 so as to be rotatable.

  When the motor 10 having the above-described configuration is supplied to the coil 21 on the stator 19 side by a predetermined energization pattern from a drive circuit unit provided outside the motor 10, a magnetic field generated in the coil 21. And the magnetic field from the rotor magnet 26 on the rotor 18 side cause the rotor 18 to rotate integrally with the rotary shaft 31. As the rotor 18 rotates, the fan 8 having a plurality of blades 25 attached to the rotor 18 also rotates integrally with the rotor 18. When the fan 8 is rotated, air outside the apparatus is sucked in the direction of the arrow D1 in FIGS. 2 and 3 through the opening 14 provided in the housing 6 and further circulates in the direction of the arrow D2. By being exhausted to the outside of the housing 6 through the through-hole 17 while circulating, the heat generated from the heating element 12 is radiated to the outside of the computer main body 3 and the inside of the computer main body 3 is cooled.

  As shown in FIGS. 4 and 5, the bearing unit 30 that rotatably supports the rotating shaft 31 of the motor 10 described above includes a radial bearing 33 that supports the rotating shaft 31 in the circumferential direction, and a thrust of the rotating shaft 31. A thrust bearing 34 that supports one end in the direction, and a radial bearing 33 and a housing 35 that houses the thrust bearing 34 are provided.

  The radial bearing 33 is formed in a cylindrical shape from sintered metal. The radial bearing 33 constitutes a hydrodynamic bearing together with lubricating oil 38, which is a viscous fluid filled in the housing 35, and a dynamic pressure generating groove 39 is formed on the inner peripheral surface through which the rotary shaft 31 is inserted. Is formed.

  As shown in FIG. 6, the dynamic pressure generating groove 39 is formed by forming a plurality of V-shaped grooves 39 a in the circumferential direction on the inner peripheral surface of the radial bearing 33. The dynamic pressure generating groove 39 is formed so that the distal ends of a pair of V-shaped grooves 39a face the rotation direction R2 of the rotation shaft 31. In this example, a pair of the dynamic pressure generating grooves 39 are formed in parallel in the axial direction of the cylindrical radial bearing 33. The number and size of the dynamic pressure generating grooves provided in the radial bearing 33 are appropriately selected depending on the size and length of the radial bearing 33. The radial bearing 33 may be made of brass, stainless steel, or a polymer material. Further, here, a plurality of dynamic pressure generating grooves are formed in a V-shape, but the present invention is not limited to this, and a plurality of V-shaped grooves on the inner peripheral surface are connected in the circumferential direction. May be formed so as to form a so-called herringbone shape.

  Here, the radial bearing 33 is formed as a so-called hydrodynamic bearing having a dynamic pressure generating groove, but the radial bearing constituting the bearing unit to which the present invention is applied is not limited to this. As long as it can support the rotating shaft 31 in the circumferential direction, for example, a sliding bearing or a sintered oil-impregnated bearing may be used.

  The radial bearing 33 formed as a hydrodynamic bearing is filled in the housing 35 when the rotary shaft 31 inserted through the radial bearing 33 continuously rotates in the direction of the arrow R2 in FIG. The lubricating oil 38 flows through the dynamic pressure generating groove 39 and supports the rotating shaft 31 rotating by generating dynamic pressure between the outer peripheral surface of the rotating shaft 31 and the inner peripheral surface of the radial bearing 33. The dynamic pressure generated at this time makes the friction coefficient between the rotating shaft 31 and the radial bearing 33 extremely small, and realizes smooth rotation of the rotating shaft 31.

  The thrust bearing 34 is disposed on the bottom surface side of the housing 35 and is formed as a pivot bearing that supports the bearing support portion 31a of the rotary shaft 31 formed in an arc shape or a tapered shape with a point.

  Further, the thrust bearing 34 has a polygonal shape on the surface of the rotating shaft 31 that supports the bearing support portion 31a, that is, the surface substantially orthogonal to the thrust direction. Here, a polygon means a thing more than a triangle, and means a plane figure surrounded by three or more line segments. Specifically, in the thrust bearing 34, for example, the above-described shape is a triangle, a quadrangle, or a hexagon.

  The thrust bearing 34 is made of a material such as a polymer such as polyether ether ketone (PEEK), nylon, 6 nylon, 6T nylon, polyoxymethylene (POM), and the like, and is a belt-like, sheet-like material or plate-like material. When the above-described shape is a triangle, a quadrangle, a hexagon, or the like, it is possible to increase the utilization efficiency of the material and reduce the cost. That is, as shown in FIGS. 7 (a), 7 (b) and 7 (c), when the shape is a triangle, a quadrangle, or a hexagon, the shape described above with reference to FIG. 14 is used. In comparison, it is possible to greatly reduce the extra portion S that does not become a thrust bearing in the material and to improve the utilization efficiency of the material. In particular, in the case of a quadrangular shape, the extra portion S can be almost eliminated. It is possible to increase the use efficiency of Further, the thrust bearing 34 having a triangular, quadrangular, or hexagonal shape can significantly reduce the unnecessary portion of the material that does not become a thrust bearing, thereby enabling the thrust cut out from a single sheet-like material or plate-like material. It is possible to increase the number of the bearings 34, thereby shortening the manufacturing process. The material of the thrust bearing 34 is not limited to the above-described polymer, and is, for example, a resin material processed into a sheet shape by adding silica, CF, polytetrafluoroethylene (PTFE), graphite, or the like. Also good. Furthermore, as a material of the thrust bearing 34, for example, a polymer containing various fillers, ceramic, quartz glass, artificial ruby, artificial sapphire, or the like may be used. The thrust bearing 34 is cut from a sheet-like material or a plate-like material by punching with a blade, laser processing, or the like, and is molded.

  Further, since the thrust bearing 34 has a polygonal shape on a surface substantially orthogonal to the thrust direction, it is possible to easily and reliably perform position restriction by a position restriction portion 36 described later provided in the housing 35. Thus, it is possible to prevent the thrust bearing 34 from rotating and misaligned.

  As shown in FIG. 5, the housing 35 housing the radial bearing 33 and the thrust bearing 34 is formed integrally with the housing main body 42 so as to close a cylindrical housing main body 42 and one end side of the housing main body 42. It consists of a bottom closing part 43 constituting one end part and an upper closing member 44 provided on the other end side of the housing main body 42 opened. The housing 35 is formed by integrating the housing body 42 and the upper closing member 44 by, for example, adhesion, ultrasonic fusion, thermal fusion, or the like. Inside the housing 35, lubricating oil 38 is filled around the bearing support portion 31a and the shaft body 31b of the rotary shaft 31. A shaft insertion hole 45 through which the rotation shaft 31 rotatably supported by a radial bearing 33 housed in the housing 35 is inserted is provided at the center of the upper closing member 44. At this time, the shaft insertion hole 45 has a gap between the inner peripheral surface and the outer peripheral surface of the rotary shaft 31 with a space sufficient to prevent the lubricating oil 38 filled in the housing 35 from leaking out of the housing 35. It is formed as follows. As described above, the housing 35 has a radial bearing 33 and a thrust bearing 34 disposed therein, and has a sealed structure except for the shaft insertion hole 45 through which the rotary shaft 31 is inserted.

  Further, as shown in FIGS. 8, 9, and 10, the bottom closing portion 43 of the housing 35 is provided with a position restricting portion 36 that restricts the position of the thrust bearing described above. The position restricting portion 36 is formed in a wall shape so as to rise from a bottom surface portion 35a serving as a reference surface on which the thrust bearing 34 is placed and to be located outside the thrust bearing 34, and the thrust bearing 34 having a rectangular shape. The first to fourth engaging portions 36a, 36b, 36c, 36d for restricting the positions of the respective top portions 34a, 34b, 34c, 34d and the first to fourth engaging portions 36a to 36d are thrust bearings 34. The wall-shaped portion is formed so as to be located on the outside so as to escape from the outer periphery Co of the rotating shaft 31 in a plane substantially orthogonal to the thrust direction. The first to fourth recesses 37a, 37b, 37c, and 37d serving as escape portions are formed. 8 shows the A1 cross section of the housing main body 42 of the housing 35 shown in FIG. 5, and FIG. 9 shows the A2 cross section of the housing main body 42 of the housing 35 shown in FIG. These show the A3 cross section shown in FIG. 8 of the housing main body 42 of the housing 35. 8, 9, and 10, the alternate long and short dash line indicates the rotating shaft 31 in order to show the positional relationship between the housing 35 and the rotating shaft 31. Further, in FIGS. 8, 9, and 10, 35 a is a bottom surface portion as a mounting surface for mounting the thrust bearing 34 of the housing 35, and 35 b is a first portion for mounting the washer 46. 1 is a mounting surface, and 35 c is a second mounting surface for mounting the radial bearing 33.

  In other words, the position restricting portion 36 is a radial direction of the rotating shaft 31 of a wall-like portion in which the first to fourth engaging portions 36a to 36d and the first to fourth recessed portions 37a to 37d are continuously formed. Is formed such that the smallest dimension X2 is larger than the dimension X1 of the outer periphery Co of the rotating shaft 31. In other words, in the position restricting portion 36, the four portions of the rising wall whose inner diameter is the dimension X2 larger than the outer dimension X1 of the rotating shaft 31 are the first to fourth engaging portions 36a to 36d. By forming, the remaining portions become the first to fourth recesses 37a to 37d. Here, the length of the diagonal line in the above-described plane of the thrust bearing 34 is set to be larger than the dimension X1 of the outer periphery of the rotating shaft 31.

  The position restricting portion 36 provided at the bottom of the housing 35 is configured such that the first to fourth engaging portions 36a to 36d are engaged with the respective top portions 34a to 34d of the thrust bearing 34 formed in a polygonal shape. The position of the bearing 34 on the surface substantially orthogonal to the thrust direction is restricted. That is, the thrust bearing 34 rotates in the direction around the axis even when the rotating shaft 31 rotates or when an impact is applied to the entire bearing unit 30. In this case, it is possible to prevent the occurrence of misalignment and the like, and the thrust bearing 34 rotates or the misalignment occurs, so that the shaft 31 of the rotating shaft 31 is generated and the rotational performance is improved. Problems such as adverse effects can be prevented.

  The position restricting portion 36 is provided with first to fourth engaging portions 36 a to 36 d and first to fourth recessed portions 37 a to 7 d formed so as to escape from the outer periphery of the rotating shaft 31. Therefore, even when the rotating shaft 31 moves to the bottom surface side of the housing 35 due to wear of the thrust bearing 34 due to long-term use, the rotating shaft 31 and the housing 35 are in contact with each other. That is, contact between the rotating shaft 31 and the housing 35 is prevented by preventing contact between the rotating shaft 31 and the wall-shaped portions constituting the first to fourth engaging portions 36 a to 36 d of the housing 35. Deterioration, scraping of the housing 35 portion, and mixing of the scraped portion of the housing 35 into the lubricating oil adversely affects the sliding or sliding contact portion of the radial bearing 33 or the thrust bearing 34. It is possible to prevent that on.

  In the above description, the position restricting portion 36 having the first to fourth engaging portions 36 a to 36 d and the first to fourth recessed portions 37 a to 37 d is provided to restrict the position of the thrust bearing 34. However, the position restricting portion constituting the bearing unit 30 to which the present invention is applied is not limited to this. For example, only the engaging portion may be formed to rise, and further, the thrust bearing. And a portion that restricts the position of the top of the polygonal shape, and may be configured as a position restricting portion that is formed outside the outer periphery of the rotating shaft 31 in a plane substantially orthogonal to the thrust direction. Further, the position restricting portion 36 is configured to have first to fourth engaging portions 36a to 36d that engage with all the tops of the rectangular thrust bearing 34 to restrict the position. What is necessary is just to comprise so that the position in the surface substantially orthogonal to a thrust direction may be controlled by having the part which controls the position of at least 3 places among the polygonal top parts of a bearing.

  Thus, since the shape of the thrust bearing 34 on the surface substantially orthogonal to the thrust direction is a polygon such as a quadrangle, the thrust bearing 34 can be reliably prevented from rotating, misaligned, and the like. The position of at least three of the top portions 34a to 34d of the thrust bearing 34 as described above is restricted, and is formed outside the outer periphery Co of the rotary shaft 31 in a plane substantially perpendicular to the thrust direction. By being engaged with the position restricting portion 36, it is possible to prevent the thrust shaft 34 and the housing 35 from contacting each other and reliably prevent the thrust bearing 34 from rotating, misaligned, and the like. Such a thrust bearing 34 supports one end of the rotating shaft 31 in the thrust direction and realizes smooth rotation of the rotating shaft 31.

  In addition, the thrust bearing constituting the bearing unit 30 to which the present invention is applied includes the shape of the first surface (front surface) on the side that supports the rotating shaft 31 and the second surface (back surface) opposite to the first surface. ) May be configured to be asymmetrical to such an extent that they can be identified as the first and second surfaces, respectively. As a configuration capable of distinguishing between the first and second surfaces, for example, in the thrust bearing constituting the bearing unit 30 to which the present invention is applied, the shape on the surface substantially orthogonal to the thrust direction is a polygon other than a regular polygon. It may be.

  Here, another example of the thrust bearing constituting the bearing unit 30 to which the present invention is applied will be described with reference to FIG. The thrust bearing 54 of another example shown in FIG. 11A has a shape on a surface (first surface) on the side that supports the bearing support portion 31a of the rotating shaft 31, that is, a surface substantially orthogonal to the thrust direction. It is a heptagon (polygon) shape in which a cutout portion serving as the identification portion 54c is provided in a rectangular quadrilateral.

  Like the thrust bearing 34 described above, the thrust bearing 54 can be easily and surely restricted by the position restricting portion 36 due to its polygonal shape, and prevents rotation, displacement and the like. It is possible to do.

  Furthermore, the thrust bearing 54 shown in FIG. 11 is a polygon other than a regular polygon, and the shapes of the front and back surfaces are asymmetric. That is, in the thrust bearing 54, as shown in FIGS. 11 (a) and 11 (b), the notch portion that becomes the identification portion 54c is shifted as one side of the rectangle, for example, to one side from the middle of the long side. The shape of the first surface (front surface) 54a on the side that supports the rotation shaft 31 is asymmetric with the shape of the second surface (back surface) 54b opposite to the first surface 54a. It is made to become a shape.

  Therefore, the thrust bearing 54 can be reliably and accurately attached without making a mistake in the front surface (first surface 54a) and the back surface (second surface 54b) when attached to the bearing unit. That is, for example, when the surface roughness of the thrust bearing 54 is different between the front and back surfaces, the surface having the desired surface roughness as the thrust bearing can be reliably disposed on the surface, and the surface on the side that supports the rotating shaft 31 can be provided. When polishing is required, conventional double-sided polishing is required, but the surface polished by single-sided polishing can be arranged so that it becomes the surface, so performance as a thrust bearing To realize the low cost.

  In the above description, the thrust bearing 54 in which the identification portion 54c is provided on one side of one side of the rectangle has been described. However, the thrust bearing capable of identifying the front and back is not limited to this. The thrust bearings 55 and 56 as shown in FIGS. 12 and 13 may be used. The thrust bearing 55 shown in FIGS. 12 (a) and 12 (b) is provided with identification portions 55c and 55d in which the dimensions L1 and L2 from the apex angle are changed on each of two adjacent sides of the square. The shape of the first surface (front surface) 55a and the shape of the second surface (back surface) 55b are asymmetrical so that the surface can be identified. Further, the thrust bearing 56 shown in FIGS. 13 (a) and 13 (b) is formed in a so-called trapezoidal shape in which the identification portion 56c is provided by removing the apex angle of the rectangular position. The shape of the surface (front surface) 56a and the shape of the second surface (back surface) 56b are asymmetrical so that the surface can be identified.

  The synthetic resin material constituting the housing 35 is not particularly limited, but it is desirable to use a material that increases the contact angle with respect to the lubricating oil 38 that repels the lubricating oil 38 filled in the housing 35. . Furthermore, it is preferable to use a synthetic resin material having excellent lubricity for the housing 35. The housing 35 is made of, for example, POM (polyoxymethylene), and is formed using a fluorine-based synthetic resin such as polyimide, polyamide, or polyacetal, or a synthetic resin such as polytetrafluoroethylene (Teflon (registered trademark)) or nylon. May be. Furthermore, a synthetic resin such as ABS (acrylonitrile butadiene styrene) may be used. Furthermore, it is formed of a liquid crystal polymer that can be molded with extremely high accuracy.

  In the bearing unit 30 described above, the housing main body 42 and the upper closing member 44 are integrally formed by fusion or the like. However, the housing constituting the bearing unit to which the present invention is applied includes For example, the housing 35 may be formed by integrally molding a resin by outsert molding or the like.

  The rotary shaft 31 rotatably supported by the radial bearing 33 and the thrust bearing 34 disposed in the housing 35 has an arc shape or a tapered tip at the bearing support portion 31a supported by the thrust bearing 34 of the shaft body 31b. The attachment part 32 to which the rotor 18 of the motor 10 which is a rotating body is attached is provided on the other end side. Here, the shaft body 31b and the mounting portion 32 are formed to have the same diameter.

  As shown in FIG. 5, the rotating shaft 31 has a bearing support portion 31a on one end side supported by a thrust bearing 34, an outer peripheral surface of the shaft portion main body 31b supported by a radial bearing 33, and an attachment portion provided on the other end side. The side 32 protrudes from a shaft insertion hole 45 provided in the upper closing member 44 of the housing body 42 and is supported by the housing 35.

  Further, the rotary shaft 31 is provided with a groove portion 31c for preventing the shaft from dropping between the bearing support portion 31a and the shaft portion main body 31b. A washer 46 is provided in the housing 35 as a shaft retaining member so as to correspond to the shaft retaining groove 31c. By engaging the shaft retaining groove 31c and the washer 46, handling during assembly is improved.

  The bearing unit described above has a housing formed of a synthetic resin, but is not limited to a synthetic resin, and is formed of a synthetic resin mixed with a metal material that can be molded using a mold apparatus or other molding materials. It may be.

  The bearing unit 30 configured as described above includes a rotating shaft 31, a radial bearing 33, a thrust bearing 34, and a housing 35, and the thrust bearing 34 has many shapes on a surface substantially orthogonal to the thrust direction. By making it square, it is possible to reliably prevent misalignment of the thrust bearing 34 such as rotation and movement, and to improve the utilization efficiency of the material of the thrust bearing. That is, the bearing unit 30 to which the present invention is applied reliably prevents misalignment such as rotation and movement of the thrust bearing 34 to prevent deterioration of rotational performance and the like, and increases the utilization efficiency of the material of the thrust bearing. Therefore, cost reduction can be realized.

  In addition, the bearing unit 30 to which the present invention is applied has a position restriction including first to fourth engagement portions 36a to 36d for restricting the position of the thrust bearing 34 on the bottom surface side of the housing 35 where the thrust bearing 34 is disposed. A portion 36 is provided, and the position restricting portion 36 has first to fourth recesses 37a to 37d serving as relief portions with respect to the outer periphery Co of the rotating shaft 31 in a plane substantially orthogonal to the thrust direction. By being formed, the thrust bearing 34 having a polygonal shape is reliably positioned, and the thrust bearing 34 is reliably prevented from being misaligned such as rotating and moving. The contact with the portion where the position restricting portion 36 is formed is prevented, the rotational performance is deteriorated due to the contact between the rotating shaft 31 and the housing 35, and the housing 35 is scraped. That adverse effects can be prevented.

  Furthermore, the bearing unit 30 to which the present invention is applied is a first bearing on the side that supports the rotating shaft 31 as shown in FIGS. 11 to 13 described above as a thrust bearing that supports one end of the rotating shaft 31 in the thrust direction. The shapes of the surfaces 54a, 55a and 56a and the shapes of the second surfaces 54b, 55b and 56b opposite to the first surface are asymmetrical enough to identify the first and second surfaces, respectively. When the thrust bearings 54, 55, and 56 having various shapes are used, the front and back surfaces of the thrust bearing can be securely and accurately attached, and only the surface that is the front surface (first surface) is provided. Since the performance as a thrust bearing can be reliably demonstrated by simply controlling the surface roughness of the surface or by polishing one side, the cost can be reduced and the performance as a thrust bearing can be demonstrated reliably. To realize the door.

  In addition, since the motor and the electronic device to which the present invention is applied include the bearing unit 30 as described above, deterioration of the rotational performance of the bearing unit 30 can be prevented over a long period of time, so that the performance as the motor and the electronic device is prolonged. It can be maintained over a period of time, and cost reduction can be realized.

  The bearing unit to which the present invention is applied can be used not only as a bearing of a motor of a heat dissipation device or a spindle motor of a disk drive, but also as a bearing of various motors.

  Furthermore, the bearing unit to which the present invention is applied can be widely used not only for a motor but also for a mechanism including a rotating shaft and a mechanism for supporting a component rotating with respect to the shaft.

It is a perspective view which shows the information processing apparatus to which this invention is applied. It is sectional drawing which shows the cross section along the II line | wire shown in FIG. It is a perspective view which shows the thermal radiation apparatus using the motor to which this invention is applied. It is sectional drawing which shows the structure of the motor to which this invention is applied. It is sectional drawing which shows the bearing unit to which this invention is applied. It is a perspective view which shows the dynamic pressure generation groove formed in the internal peripheral surface of a radial bearing. It is a figure explaining forming a thrust bearing by cutting out from a strip-shaped material, (a) is a top view of a material in the case of cutting out a thrust bearing formed in a triangle shape, (b) is a square It is a top view of the raw material in the case of cutting out the thrust bearing formed in a shape, (c) is a top view of the raw material in the case of cutting out a thrust bearing formed in a hexagonal shape. It is a figure which shows the plane cross section of the housing which comprises the bearing unit to which this invention is applied, and is sectional drawing which shows the A1-A1 cross section shown in FIG. It is sectional drawing which shows the A2-A2 cross section shown in FIG. 8 of a housing. It is sectional drawing which shows the A3-A3 cross section shown in FIG. 8 of a housing. It is a figure which shows the other example of the thrust bearing which comprises the bearing unit to which this invention is applied, (a) is a top view which shows the 1st surface of the side which supports a rotating shaft, (b) It is a top view which shows a 2nd surface. It is a figure which shows the further another example of a thrust bearing, (a) is a top view which shows a 1st surface, (b) is a top view which shows a 2nd surface. It is a figure which shows the further another example of a thrust bearing, (a) is a top view which shows a 1st surface, (b) is a top view which shows a 2nd surface. It is a figure for demonstrating forming the thrust bearing used for the conventional bearing unit by cutting out from a strip | belt-shaped raw material, and is a top view of the raw material in the case of cutting out the thrust bearing formed circularly.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Motor, 18 Rotor, 19 Stator, 20 Stator yoke, 24 Rotor yoke, 30 Bearing unit, 31 Rotary shaft, 33 Radial bearing, 34 Thrust bearing, 35 Housing, 36 Position control part, 38 Lubricating oil, 39 Dynamic pressure generating groove, 42 housing body, 43 bottom closing part, 44 top closing member, 45 shaft insertion hole, 46 washer

Claims (8)

The axis,
A radial bearing for supporting the shaft in the circumferential direction;
A thrust bearing that supports one end of the shaft in the thrust direction;
A housing in which the radial bearing and the thrust bearing are disposed;
The thrust bearing is a bearing unit having a polygonal shape on a surface substantially orthogonal to the thrust direction.   The bearing unit according to claim 1, wherein the thrust bearing has a shape other than a regular polygon in a shape substantially orthogonal to the thrust direction.   The bearing unit according to claim 1, wherein the thrust bearing has a triangular, quadrangular, or hexagonal shape on a surface substantially orthogonal to the thrust direction.   The thrust bearing has an asymmetric shape on a surface substantially orthogonal to the thrust direction, the shape of the first surface on the side supporting the shaft, and the second surface on the opposite side of the first surface. The bearing unit according to claim 1, wherein the shape of each of the first and second surfaces can be identified.   The bearing unit according to claim 1, wherein the housing is provided with an engaging portion that engages with a polygonal top portion of the thrust bearing to regulate a position of the thrust bearing.   The bearing unit according to claim 5, wherein the engagement portion is formed outside the outer periphery of the shaft in a plane substantially orthogonal to the thrust direction. In a motor having a bearing unit that rotatably supports a rotor with respect to a stator,
The bearing unit includes a shaft,
A radial bearing for supporting the shaft in the circumferential direction;
A thrust bearing that supports one end of the shaft in the thrust direction;
A housing in which the radial bearing and the thrust bearing are disposed;
The thrust bearing is a motor having a polygonal shape on a surface substantially orthogonal to the thrust direction. An electronic device including a motor having a bearing unit that rotatably supports a rotor with respect to a stator,
The bearing unit includes a shaft,
A radial bearing for supporting the shaft in the circumferential direction;
A thrust bearing that supports one end of the shaft in the thrust direction;
A housing in which the radial bearing and the thrust bearing are disposed;
The thrust bearing is an electronic device having a polygonal shape on a surface substantially perpendicular to the thrust direction.

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