JPH0742563U - Brushless motor - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to an axial gap type brushless motor, and an object thereof is to prevent warpage of a substrate facing a rotor magnet. [Structure] A coil 23 formed in a predetermined number on a metal substrate 22.
And a magnet 28 provided on a turntable 26 rotatably attached to the spindle 25 are arranged to face each other, and the back surface of the metal substrate 22 is prevented from being warped due to the attraction force of the magnet 28. The reinforcing plate 32 having the steps 32a and 32b formed therein is fixed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an axial gap type brushless motor.

[0002]

[Prior art]

 In recent years, a DC brushless motor has been generally used as a motor for rotating a disk of a recording medium in a disk device. Further, the brushless motor has been made thinner due to the demand for thinner devices, and there are an axial gap structure and a radial gap structure.

Compared to the radial gap structure, the axial gap structure does not require a gear type core and windings for it, and various coil assemblies are arranged on an iron substrate used as a magnetic yoke. The same effect can be obtained simply by fixing. Therefore, FIG. 8 shows a schematic diagram of a conventional axial gap type brushless motor structure. In FIG. 8A, in the brushless motor 11, a predetermined number of coils 14 are formed around a spindle 13 on an iron substrate 12 on the stator side, and a rotor magnet (permanent magnet) 15 is rotatably attached to the spindle 13. When the coil 14 is energized, the rotor magnet 15 rotates. In the disc device, the rotor magnet 15 serves as a turntable to rotate the disc.

By the way, in the brushless motor 11 having the above-described structure, since the iron substrate 12 and the rotor magnet 15 are opposed to each other, the iron substrate 12 is attracted by the rotor magnet 15 as shown in FIG. 8B. 12 is attracted and deformed, and a warp occurs on the rotor magnet 15 side. That is, the iron substrate 12 warps in a substantially concave curved surface centering on the spindle 13, and the warping becomes more remarkable as the diameter of the rotor magnet 15 increases. Therefore, the gap between the coil 14 and the rotor magnet 15 is reduced, which deteriorates the rotation characteristics.

Therefore, for the purpose of satisfying the motor characteristics with a magnet having a necessary energy product and for reducing the warp by reducing the diameter, the rotor magnet 15 may be formed of an Nd-Fe-B system magnet. It is being appreciated. If the effect of warpage cannot be ignored, it is avoided by combining FPC (flexible printed circuit board) as the iron substrate 12 and a silicon steel plate in a direction opposite to the warpage by performing reverse warpage processing and a yoke in combination. Is done.

[0006]

[Problems to be solved by the device]

 However, in order to avoid the influence of warpage of the iron substrate 12, the iron substrate 12 itself cannot be subjected to reverse warpage processing and is composed of the above-mentioned silicon steel plate and FPC. There is a problem that the number of points and the number of assembling steps increase and the overall cost increases.

Further, in a brushless motor whose thickness is not restricted, it is cost effective to form the rotor magnet by an inexpensive ferrite magnet, but the diameter is increased and the attraction force is increased. There is a problem that the warp becomes large as shown in B). Then, this invention is made | formed in view of the said subject, and it aims at providing the brushless motor which prevents the curvature of a board | substrate with respect to a rotor magnet.

[0008]

[Means for Solving the Problems]

 The above-mentioned problem is solved by a substrate formed of a magnetic member and provided with a predetermined number of coils wound around the attached bearing, and a rotating shaft inserted through the bearing, and the coil and a predetermined gap. And a rotor provided with a magnet facing each other, and attached to the opposite side of the substrate from the rotor to restrict deformation of the substrate in the attraction direction by the magnet, and to reduce the gap length between the coil and the magnet. This is solved by adopting a configuration having a regulating member to be maintained.

[0009]

[Action]

 As described above, the regulating member is attached to the side of the substrate opposite to the rotating body. The regulation member regulates a place where the substrate is attracted by the attraction force of the magnet and is about to be deformed toward the magnet by applying a pressing force in the opposite direction. As a result, the warp of the substrate toward the magnet side is prevented, the gap length between the coil and the gap is maintained, and the influence of the warp on the motor can be avoided.

In addition, since the warp of the substrate is prevented, it is possible to reduce the cost without the need to use an FPC or a reverse warped silicon steel plate, and in a motor that does not require thinness. Inexpensive magnets can be used and the cost can be reduced.

[0011]

【Example】

FIG. 1 shows a block diagram of a first embodiment of the present invention. FIG. 1 is a partial vertical cross-sectional view of an axial gap type brushless motor, showing a thin brushless motor 21 _A used particularly in a thin disk device. In FIG. 1, a predetermined wiring pattern is formed on a metal substrate 22 formed of a magnetic member (iron) and used as a magnetic yoke, and a predetermined number of wound coils 23 are formed and arranged. Set up. The thickness of the metal substrate 22 is about 0.2 mm, which is 30 to 40% thinner than the conventional thickness within the range where magnetic saturation does not occur.

A hole 22 a is formed in the center of the metal substrate 22 to attach a bearing 24, and a spindle 25, which is a rotating shaft, is inserted into the bearing 24. A turntable 26, which is a rotating body, is attached to the spindle 25. . A drive pin 27 is provided on the turntable 26 so as to be vertically movable. On the back surface of the turntable 26, a doughnut-shaped magnet 28 of, for example, an Nd-Fe-B system is provided. An upper plate 29a is arranged on the turntable 26 and a lower plate 29b is arranged on the metal substrate 22 around the bearing 24. A ball bearing 30 is arranged between the upper plate 29a and the lower plate 29b to allow the turntable 26 to rotate above the metal substrate 22.

On the other hand, a predetermined number of cylindrical hole portions 31 (described in FIG. 2) are formed on the side of the metal substrate 22 opposite to the turntable 26 (the back surface of the metal substrate 22). Then, the reinforcing plate 32, which is a restricting member, is attached to the cylindrical portion 31 by caulking pins 33 in a close contact state. The reinforcing plate 32 is formed with two steps 32a and 32b so that the thickness increases toward the hole 22a of the metal substrate 22, and is attached to the metal substrate 22 in a bent state.

Here, FIGS. 2 and 3 are explanatory views of the assembly structure of FIG. In FIG. 2A, a hole 22a is formed in the center of a metal substrate 22 (coils are omitted), and cylindrical holes 31 are formed at four corners by, for example, burring. On the back surface of the metal substrate 22, steps 32a and 32b, which are disk-shaped and are concentrically thin on the circumferential side of the hole 32c, are formed, and four mounting portions corresponding to the cylindrical hole portion 31 are provided on the periphery. The reinforcing plate 32 in which the hole 32d is formed is located. Then, the bearing 24 is attached by caulking to the hole 22a (the hole 32c of the reinforcing plate 32) on the metal substrate 22 to fix the metal substrate 22 and the reinforcing plate 32.

Such a state is shown in FIG. 2 (B). Then, as shown in FIG. 2C, the cylindrical hole portion 31 of the metal substrate 22 is fitted into the mounting hole 32 d of the reinforcing plate 32 and fixed by the caulking pin 33. At this time, the metal substrate 22 is bent and deformed along the steps 32a and 32c of the reinforcing plate 32 while being warped downward in the drawing. The heights of the steps 32a and 32b of the reinforcing plate 32 are set (for example, about 0.2 mm) by calculating the correction amount of reverse warpage from the amount of warpage of the metal substrate 22 by the magnet 28. Therefore, as described above, the thickness of the metal substrate 22 is reduced so that the overall thickness is not increased.

By the way, in the above example, the case where the reinforcing plate 32 is fixed to the metal substrate 22 by caulking is shown, but when there is a space in the metal substrate 22, the reinforcing plate 32 may be fixed by a rotating self clamp. Subsequently, as shown in FIG. 3A, the spindle 24 having the turntable 26 attached to the bearing 24 is inserted and positioned. At this time, as shown in FIG. 3B, the metal substrate 22 is attracted by the magnet 28 of the turntable 26 and is bent and deformed in the direction of the magnet 28 together with the reinforcing plate 32. In this state, the turntable 26 and the metal substrate 22 are substantially parallel to each other. That is, in a substantially parallel state, the attraction force of the magnet 28 attracting the metal substrate 22 and the force of the bent reinforcing plate 32 to restore are balanced, resulting in the warpage of the metal substrate 22. Is prevented.

As a result, the gap length between the coil 23 and the magnet 28 is maintained as shown in FIG. 1, and the influence on the motor characteristics can be avoided. Here, FIG. 4 shows a sectional view of another example of the shape of the reinforcing plate of FIG. In FIG. 4A, the reinforcing plate 32 _A is formed by pressing a metal plate to form steps 32 _Aa and 32 _Ab . In FIG. 4B, the reinforcing plate 32 _B is formed of a metal plate having a predetermined thickness to form the tapered portion 32 _Ba by cutting or the like. Further, FIG. 4C shows the reinforcing plate 32 _C formed by pressing a metal plate to form a taper 32 _Ca.

Next, FIG. 5 shows an explanatory view of another attachment of the reinforcing plate of the first embodiment. In FIG. 5, the metal substrate 22 has three engaging grooves to form notches 34a to 34c, and the reinforcing plate 32 is surrounded by engaging projections 35a to 35c corresponding to the notches 34a to 34c. 35c is formed. That is, the engaging projections 35a to 35c of the reinforcing plate 32 are engaged with the cutouts 34a to 34c of the metal base plate 22, and are rotated to the locking grooves of the cutouts 34a to 34c to be locked and fixed. is there.

Next, FIG. 6 shows a block diagram of a second embodiment of the present invention. Brushless motors 21 _B shown in FIG. 6 shows a partial longitudinal cross-sectional side view similar to FIG. 1. This brushless motor 21 _B is used in a disk device having a standard thickness, and can be configured with a margin in thickness as compared with FIG. As shown in FIG. 6, the turntable 2 6a which is attached to the spindle motor 25 by way of a step 26a ₁ is formed corresponding to the motor thickness, the magnet 28a is energy product required, such as for example an inexpensive ferrite backside Is provided with a thickness.

On the other hand, in the metal substrate 22 _A , a predetermined number of coils 23 facing the magnet 28 a are formed, and a predetermined number of cylindrical hole portions 37 a are formed. Then, a reinforcing plate 32 _D having a thickness corresponding to the magnet 28 a (thickness of about 0.8 mm due to an increase in the attraction force) is arranged on the back surface of the metal substrate 22 _A , forming steps 32 _Da and 32 _Db . It is fixed to the metal substrate 22 _A by caulking or the like.

In this case, the reinforcing plate 32 _D is formed in a mortar shape from the end of the metal substrate 22 _A toward the ball bearing 30, and the ball bearing 25 forms a part of the turntable 26 a, the drive pin 27, the ball bearing 30, The upper plate 27a and the lower plate 29b can be made common to the first embodiment. Incidentally, the effect of preventing warpage of the metal substrate 22 _A is similar to the first embodiment, a large mug net 28a metallic substrate 22 _A by balancing the restoring force by the suction force and a thick reinforcing plate 32 _D by no warping state Thus, the gap length between the coil 23 and the magnet 28a is maintained. That is, the cost of the brushless motor 21 _B can be reduced.

Next, FIG. 7 shows a block diagram of a third embodiment of the present invention. The brushless motor 21c shown in FIG. 7 is a modified example of the second embodiment shown in FIG. 6, and uses a bearing 24a having an upwardly extending shape, and uses the metal substrate 22 and the reinforcing plate 32 as the first embodiment. This is for common use. The turntable 26a and the magnet 28a are the same as in the first embodiment. A lower plate 29b is arranged on the bearing 24a.

In this case, since the thickness of the reinforcing plate 32 is smaller than the size of the magnet 28a, the gap length between the coil 23 and the magnet 28a is set longer than in the first and second embodiments. The gap length is maintained in a state where the metal substrate 22 is not warped by balancing the attraction force of the magnet 28a and the restoring force of the reinforcing plate 32. As a result, the cost of the brushless motor 21c can be reduced as in the second embodiment.

[0024]

[Effect of device]

 As described above, according to the present invention, by providing the control member on the opposite side of the rotating body of the substrate from the deformation of the substrate in the attraction direction by the magnet and maintaining the gap length between the coil and the magnet, It is possible to prevent the warp due to the suction force of the substrate facing the substrate, avoid the influence of the motor characteristics, and reduce the cost.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is an explanatory view (1) of the assembly structure of FIG.

FIG. 3 is an explanatory diagram (2) of the assembly structure of FIG. 1.

4 is a cross-sectional view showing another example of the shape of the reinforcing plate of FIG.

FIG. 5 is an explanatory view showing another attachment of the reinforcing plate of the first embodiment.

FIG. 6 is a configuration diagram of a second embodiment of the present invention.

FIG. 7 is a configuration diagram of a third embodiment of the present invention.

FIG. 8 is a conceptual diagram of a conventional axial gap type brushless motor structure.

[Explanation of symbols]

21 _{A to} 21 _C Brushless motor 22 Metal board 23 Coil 24 Bearing 25 Spindle 26 Turntable 27 Drive pin 28 Magnet 32 Reinforcing plate 33 Caulking pin

[Procedure amendment]

[Submission date] January 27, 1994

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

[Figure 8]

Claims (1)

[Scope of utility model registration request] 1. A substrate formed of a magnetic member and provided with a predetermined number of coils wound around an attached bearing, and a substrate mounted on a rotating shaft inserted through the bearing, and the coil and the predetermined number. A rotating body including a magnet facing each other with a gap, and attached to the side of the substrate opposite to the rotating body, restricting deformation of the substrate in the attraction direction by the magnet, and a gap length between the coil and the magnet. A brushless motor having a regulating member for maintaining the above.