JP2005302205A - Spindle motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the cost of a spindle motor of an optical disk device by reducing the total length of the shaft of the spindle motor. <P>SOLUTION: A positioning recessed section 22 and a fixed projecting section 23 are formed on a turntable 8 to couple the turntable 8 to a rotor case 7. A positioning projected section 26 which is engaged with the positioning recessed section 22, a fixed hole 27 into which the fixed projecting section 23 is penetrated and a shaft coupling projected section 28 into which a shaft 6 is force-fitted are formed at the end face 25 of the rotor case 7. By force-fitting the shaft 6 into the shaft coupling projected section 28, the rotor case 7 and the shaft 6 are coupled, the positioning projected section 26 is engaged with the positioning recessed section 22, the fixed projecting section 23 penetrates into the fixed hole 27 and the turntable 8 and the rotor case 7 are coupled by the fixing of the tip 30 of the fixed projecting section 23 to the peripheral section of the fixed hole 27. Thus, without needing to provide a fitting section which is normally required to directly force-fitting the turntable 8 to the tip of the shaft 6, the shaft 6 and the turntable 8 are coupled and the length of the shaft 6 is reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a spindle motor for rotationally driving a turntable of an optical disc apparatus.

  2. Description of the Related Art Conventionally, an optical disc apparatus that writes and reads data by rotating an optical disc and irradiating the recording surface with laser light has been put into practical use. FIG. 4 shows the structure of a conventional general spindle motor for rotationally driving an optical disk. The spindle motor 101 includes a stator 102 fixed to a substrate 117 and a rotor 103 that rotates with respect to the stator 102. The stator 102 includes a bearing 104 for supporting the shaft 106, a coil 105 for rotating the rotor 103, and the like. The rotor 103 includes a shaft 106 rotatably supported by a bearing 104, a rotor case 107 that rotates together with the shaft 106, a turntable 108 that rotates together with the shaft 106 while chucking an optical disk, and a magnetic field generated by a coil 105. The magnet 109 is driven in response to this.

  The bearing 104 is held by a bearing holder 110. The bearing holder 110 is attached to the substrate via the mounting plate 114. The coil 105 is wound around an iron core 119 formed radially with respect to the bearing holder 110.

  The turntable 108 is made of resin, and a fitting portion 140 at the tip of the shaft 106 is coupled to the center of rotation by press-fitting or insert molding. The rotor case 107 includes a cylindrical portion 124 for holding the magnet 109 facing the coil 105, an end surface portion 125 to which the shaft 106 is coupled, and the like. The shaft 106 is coupled to the rotor case 107 by being press-fitted into the shaft coupling convex portion 128 of the rotor case 107.

In addition, as what has a structure comparatively similar to the spindle motor 101 shown in FIG. 4, the turntable press-fitted into the shaft, the center ring for positioning the optical disk, and the turntable and the center ring are separated from each other. A spindle motor provided with a coil spring or the like for biasing in the direction is known (see, for example, Patent Document 1). Also known is a spindle motor including a turntable press-fitted into a shaft, a bearing directly inserted into a stator core, and a rotor case integrated with the turntable (see, for example, Patent Document 2 and Patent Document 3). )
JP 2000-30357 A JP-A-9-252568 Japanese Utility Model Publication No. 63-66069

  However, the conventional spindle motor 101 shown in FIG. 4 has a structure in which the shaft 106 is press-fitted or insert-molded into the turntable 108 at the fitting portion 140. In addition, the length of the fitting portion 140 at the tip of the shaft 106 must be ensured to be equal to or more than a corresponding dimension. For this reason, the entire length of the shaft 106 becomes long, and it becomes difficult to reduce the cost and size of the optical disc apparatus. Further, any of the spindle motors shown in any of the above patent documents has the same structure as the spindle motor 101 shown in FIG. 4 in that the shaft is press-fitted into the turntable. The problem cannot be solved.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a spindle motor that realizes cost reduction and downsizing of the apparatus by enabling the overall length of the shaft to be shortened.

  In order to achieve the above object, the invention of claim 1 includes a shaft that is rotatably supported, a rotor case that rotates together with the shaft, a turntable that rotates together with the shaft while chucking an optical disk, and a rotor having a magnet. , A bearing member that supports the shaft, and a spindle motor that includes a stator having a coil for rotationally driving the rotor via a magnet, wherein the turntable has a positioning recess and a fixed protrusion for coupling with the rotor case The rotor case has a cylindrical portion to which the magnet is coupled to the inner peripheral surface, and an end surface portion that is positioned between the stator and the turntable and to which the shaft and the turntable are coupled. The positioning convex part that engages the positioning concave part of the turntable and the fixing of the turntable It has a fixed hole through which the part penetrates and a shaft coupling convex part into which the shaft is press-fitted, and the positioning convex part is formed by burring so as to protrude to the turntable side, and the shaft coupling convex part is It is formed by burring so as to protrude to the stator side, and when the shaft is press-fitted into the shaft coupling convex portion of the rotor case, the rotor case and the shaft are coupled, and the positioning convex of the rotor case is inserted into the positioning concave portion of the turntable. The turn table is positioned on the rotor case, and the fixed convex portion of the turn table is penetrated through the fixing hole of the rotor case, and the tip portion thereof is the periphery of the fixing hole. The turntable and the rotor case are joined by being fixed to the part, and the fitting for directly press-fitting the turntable into the tip of the shaft Without providing a bind and the shaft and the turntable is obtained by shortening the overall length of the shaft.

  The invention according to claim 2 is a shaft that is rotatably supported, a rotor case that rotates together with the shaft, a turntable that rotates together with the shaft while chucking an optical disk, a rotor having a magnet, and a bearing member that supports the shaft , And a spindle motor having a stator having a coil for rotationally driving the rotor via a magnet, the rotor case has a cylindrical portion where the magnet is coupled to the inner peripheral surface, and a shaft and a turntable. An end surface portion, the end surface portion is located between the stator and the turntable, and has a shaft coupling convex portion into which the shaft is press-fitted, and the shaft is press-fitted into the shaft coupling convex portion of the rotor case. By connecting the rotor case and the shaft, the turntable and the rotor case are further connected. By being, without providing a fitting portion for press-fit directly on the turntable at the tip portion of the shaft, combines with said shaft and the turntable is obtained by shortening the overall length of the shaft.

  According to a third aspect of the present invention, in the spindle motor according to the second aspect, the turntable has a concave portion to be coupled to the rotor case, and the side surface portion of the rotor case is a convex portion that engages with the concave portion of the turntable. The convex portion and the shaft coupling convex portion of the rotor case are formed by burring so as to protrude to the turntable side.

  According to the first aspect of the present invention, the shaft and the turntable can be coupled via the rotor case without providing a fitting portion for directly press-fitting into the turntable at the tip of the shaft, so that the total length of the shaft is shortened. This makes it possible to reduce the cost and thickness of the apparatus. Further, by engaging the positioning convex portion of the rotor case with the positioning concave portion of the turn table, the turn table is positioned on the rotor case, so that the turn table and the rotor case can be coupled with high accuracy. In addition, the turntable and the rotor case are coupled by passing the fixing convex part of the turntable through the fixing hole of the rotor case and fixing the tip part to the peripheral part of the fixing hole, so that the spindle motor can be easily assembled. Can be done.

  According to the invention of claim 2, the shaft and the turntable can be coupled via the rotor case without providing a fitting portion for directly press-fitting into the turntable at the tip of the shaft, so that the total length of the shaft is shortened. This makes it possible to reduce the cost and thickness of the apparatus.

  According to invention of Claim 3, since the positioning convex part and the axial coupling convex part protrude in the same direction, both can be shape | molded by one press process. Thereby, the molding process of the rotor case is simplified and the productivity of the spindle motor can be further enhanced. Further, since the gap between the end surface portion of the rotor case and the bearing can be reduced, the height dimension of the spindle motor including the turntable can be reduced.

(Embodiment 1)
A spindle motor according to the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 shows a side section of the spindle motor. The spindle motor 1 has a stator 2 fixed to a substrate 17 and a rotor 3 that rotates with respect to the stator 2. The stator 2 includes a bearing (oil-impregnated bearing) 4 for supporting the shaft 6 and a coil 5 for rotating the rotor 3. The rotor 3 includes a shaft 6 that is rotatably supported by a bearing 4, a rotor case 7 that rotates together with the shaft 6, a turntable 8 that rotates together with the shaft 6 while chucking the optical disk, a magnet 9 that is driven by the coil 5, and the like. It is constituted by.

  The bearing 4 is held by a bearing holder 10. Washers 11 and 12 for holding the shaft 6 in the axial direction are provided at both ends of the bearing 4. A washer 13 is also disposed between the inner bottom of the bearing holder 10 and the end of the shaft 6. The bearing holder 10 is press-fitted into the cylindrical portion 15 of the mounting plate 14. The mounting plate 14 is attached to the substrate 17 with screws 16. A Hall element 18 for detecting the rotation of the rotor 3 is mounted at a position facing one place on the circumference of the magnet 9 of the substrate 17. The coil 5 is wound around an iron core 19 that is radially coupled from the bearing holder 10.

  The turntable 8 is made of resin. On one side surface (upper surface in the figure) of the turntable 8, a ring-shaped rubber sheet 20 for holding the optical disk from the recording surface side is provided at the peripheral edge, and the optical disk is labeled in the vicinity of the rotation center. A magnet 21 for attracting a clamper (not shown) held from the surface side is provided. A pair of positioning concave portions 22 and fixed convex portions 23 for coupling to the rotor case 7 are provided on the other side surface (lower surface in the drawing) of the turntable 8.

  FIG. 2 shows the appearance of the rotor case 7. The rotor case 7 is formed by pressing a metal plate, and is positioned between the cylindrical portion 24 for holding the magnet 9 so as to be opposed to the coil 5 and between the coil 5 and the turntable 8. It is comprised by the end surface part 25 grade | etc., With which the shaft 6 is couple | bonded with a part. The end surface portion 25 includes a pair of positioning convex portions 26 that engage with the positioning concave portion 22 of the turntable 8, a pair of fixing holes 27 through which the fixing convex portion 23 of the turntable 8 passes, and a shaft into which the shaft 6 is press-fitted. And a coupling convex portion 28. The shaft coupling convex portion 28 is disposed at the center of the end surface portion 25, and each positioning convex portion 26 and each fixing hole 27 are disposed so as to be aligned on the same straight line with the shaft coupling convex portion 28 interposed therebetween. The positioning convex portion 26 is formed by burring so as to protrude toward the turntable 8, and the shaft coupling convex portion 28 is formed by burring so as to protrude toward the stator 2. Further, a magnet 29 for attracting the clamper more strongly as necessary is provided near the outer periphery of the shaft coupling convex portion 28.

  Next, the procedure for assembling the rotor 3 of the spindle motor 1 will be described. First, the rotor case 7 and the shaft 6 are coupled by press-fitting the shaft 6 into the shaft coupling convex portion 28 of the rotor case 7. Then, the positioning convex portion 26 of the rotor case 7 is engaged with the positioning concave portion 22 of the turntable 8. Thereby, the turntable 8 is accurately positioned on the rotor case 7. At this time, the fixed convex portion 23 of the turntable 8 passes through the fixed hole 27 of the rotor case 7, and the tip portion 30 protrudes to the inner surface side of the rotor case 7. Thereafter, the tip portion 30 protruding to the inner surface side of the rotor case 7 is fixed to the peripheral portion of the fixing hole 27 by heat welding or the like, whereby the turntable 8 and the rotor case 7 are integrally coupled, and the shaft 6 The turntable 8 is integrally coupled.

  As described above, according to this embodiment, the shaft 6 and the turntable can be provided without providing the fitting portion 140 as shown in FIG. 4 for directly press-fitting the shaft 6 into the turntable 8 at the tip of the shaft 6. 8 can be coupled to each other via the rotor case 7, so that the entire length of the shaft 6 can be shortened. As a specific numerical value, the shaft 6 can be made shorter by about 4 mm than the conventional shaft 106 shown in FIG. Since the shaft is formed of a relatively expensive material such as SUS (stainless steel), the cost can be reduced. If the spindle motor 1 can be supplied in large quantities, the cost can be considerably reduced as a whole. Further, by shortening the shaft 6, it is possible to make the entire motor thinner.

  Further, by engaging the positioning convex portion 26 of the rotor case 7 with the positioning concave portion 22 of the turntable 8, the turntable 8 is positioned on the rotor case 7, so that the turntable 8 and the rotor case 7 can be accurately aligned. Can be combined well. Further, the turntable 8 and the rotor case 7 are coupled by causing the fixing protrusion 27 of the turntable 8 to pass through the fixing hole 27 of the rotor case 7 and fixing the tip 30 thereof to the peripheral edge of the fixing hole 27. Therefore, the spindle motor 1 can be easily assembled.

(Embodiment 2)
Another embodiment of the present invention will be described with reference to FIG. The spindle motor 31 of the present embodiment is different from the spindle motor 1 of the first embodiment in that the shaft coupling convex portion 33 of the rotor case 32 is formed so as to protrude toward the turntable 8. According to this embodiment, since the positioning convex part 26 and the shaft coupling convex part 33 protrude in the same direction, both can be shape | molded by one press process. Thereby, the molding process of the rotor case 32 is simplified, and the productivity of the spindle motor 31 can be further enhanced. In addition, since the distance between the end surface portion 25 of the rotor case 32 and the bearing 4 (washer 12) can be reduced, the height of the spindle motor 31 can be reduced.

  The present invention is not limited to the configuration of the above embodiment, and various modifications can be made. For example, the positioning convex portion 26 is not limited to the one by burring processing, and may be formed by projecting from the end surface portion 25 to the turntable 8 side by normal pressing. Further, the points and positions of the positioning convex portion 26 and the shaft coupling convex portion 28 are not limited to those shown in FIG. 2, for example, three or more points may be formed, and each may have a predetermined angle. It may be arranged so as to be shifted. Further, the positioning convex portion 26 may be arranged on the outer peripheral side from the fixing hole 27.

1 is a side sectional view showing a structure of a spindle motor according to an embodiment of the present invention. The perspective view which shows the shape of the rotor case of the motor. The sectional side view which shows the structure of the spindle motor by another embodiment of this invention. The sectional side view which shows the structure of the conventional spindle motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Spindle motor 2 Stator 3 Rotor 4 Bearing 5 Coil 6 Shaft 7 Rotor case 8 Turntable 9 Magnet 22 Positioning recessed part 23 Fixed convex part 25 End surface part 26 Positioning convex part 27 Fixed hole 28 Shaft coupling convex part 31 Spindle motor 32 Shaft coupling convex part Part

Claims (3)

A shaft that is rotatably supported, a rotor case that rotates together with the shaft, a turntable that rotates together with the shaft while chucking an optical disk, and a rotor having a magnet;
In a spindle motor comprising a bearing member for supporting the shaft, and a stator having a coil for rotationally driving the rotor via the magnet,
The turntable has a positioning concave portion and a fixed convex portion to be coupled with the rotor case,
The rotor case includes a cylindrical portion where the magnet is coupled to an inner peripheral surface, and an end surface portion which is positioned between the stator and the turntable and to which the shaft and the turntable are coupled. Has a positioning convex part that engages with the positioning concave part of the turntable, a fixing hole through which the fixed convex part of the turntable passes, and a shaft coupling convex part into which the shaft is press-fitted,
The positioning convex portion is formed by burring so as to protrude toward the turntable side, and the shaft coupling convex portion is formed by burring so as to protrude toward the stator side,
When the shaft is press-fitted into the shaft coupling convex portion of the rotor case, the rotor case and the shaft are coupled, and the positioning convex portion of the rotor case is engaged with the positioning concave portion of the turntable, The turntable is positioned on the rotor case, and the fixed convex portion of the turntable is penetrated through the fixing hole of the rotor case, and the tip end thereof is fixed to the peripheral portion of the fixing hole. And rotor case are combined,
A spindle motor characterized in that the entire length of the shaft is shortened by connecting the shaft and the turntable without providing a fitting portion for directly press-fitting the turntable at the tip of the shaft. A shaft that is rotatably supported, a rotor case that rotates with the shaft, a turntable that rotates with the shaft while chucking an optical disk, and a rotor having a magnet;
In a spindle motor comprising a bearing member for supporting the shaft, and a stator having a coil for rotationally driving the rotor via the magnet,
The rotor case has a cylindrical portion to which the magnet is coupled to an inner peripheral surface, and an end surface portion to which the shaft and the turntable are coupled, and the end surface portion is located between the stator and the turntable. And having a shaft coupling convex part into which the shaft is press-fitted,
When the shaft is press-fitted into the shaft coupling convex portion of the rotor case, the rotor case and the shaft are coupled, and further, when the turntable and the rotor case are coupled, the turntable is disposed at the tip of the shaft. A spindle motor characterized in that the shaft and the turntable are coupled and the overall length of the shaft is shortened without providing a fitting portion for directly press-fitting into the shaft. The turntable has a recess for being coupled with the rotor case,
The side surface portion of the rotor case has a convex portion that engages with the concave portion of the turntable,
The spindle motor according to claim 2, wherein the convex portion of the rotor case and the shaft coupling convex portion are formed by burring so as to protrude toward the turntable.

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