JPH0677482U - Brushless motor - Google Patents

Abstract

(57) [Summary] [Purpose] The thrust pressure can be adjusted after assembly. [Structure] A rotor case 11 is fixed to a rotary shaft 40 at one end of a spindle 40 by screwing. A thrust washer 61 and a thrust spring 60 are sequentially inserted between the lower end of the bearing 31 and the rotor case 11. A plurality of bent pieces 11a are formed in a substantially concentric shape at the center of the rotor case 11. By displacing the bent portion 11a of the rotor case 11 to the bearing 31 side in the motor assembled state, the elastic force applied from the thrust spring 60 to the thrust washer 61 increases, and the thrust pressure can be increased.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a brushless motor.

[0002]

[Prior art]

 A conventional example of a brushless motor is shown in FIG. This motor is a motor (step motor) with a brushless core used for a flexible magnetic disk (trade name “floppy disk”) drive device, and a rotor set 110 in which a drive magnet 112 is arranged inside a rotor case 111, It is composed of a stator set 120 that is configured by electrically connecting an electric element component and a core winding set 122 to a substrate 121, and a bearing set 130 that rotatably holds a rotor set 110.

The rotor set 110 is inserted into one end of the spindle 140 and fixed to the spindle 140 by screwing. A hub 150 is joined to the other end of the spindle 140, which is the opposite surface side of the rotor set 110, by press fitting or the like. With this structure, the spindle 140 is held in a non-separable state in the axial direction.

In the brushless motor configured as described above, it is unavoidable that an error occurs in the stacking dimension due to the assembly accuracy of the spindle 140 and the hub 150, the dimensional accuracy of the bearing assembly 130, and the like. Therefore, in Fig. 7, by setting A, which is the actual mounting dimension, to be slightly larger than b, which is the design dimension, and providing an appropriate gap, after the screw tightening regardless of the above dimension error. The rotor set 110 is surely held rotatably. Further, a thrust spring 160 is inserted between the rotor case 111 and the bearing assembly 130, and the thrust pressure generated by the thrust spring 160 pushes the rotor case 111 downward in FIG. 7, thereby causing play (thrust play) in the thrust direction. ) Is absorbed to prevent fluctuation of the rotor set 110 in the thrust direction during motor rotation.

As the thrust spring 160, one in which a plurality of spring elastic pieces 162 are formed on the outer periphery is known as shown in FIG. 8, and the thrust pressure is generated by these spring elastic pieces 162. After mounting the thrust spring 160, the rotor set 110 is screwed to the spindle 140 as described above.

[0006]

[Problems to be solved by the device]

 By the way, in the brushless motor as described above, it is difficult to control the thrust pressure within a predetermined range because the thrust pressure fluctuates due to variations in the stacking dimension of the parts. In the case of the conventional brushless motor having the above structure, the thrust pressure acting on the rotor case or the like by the thrust spring cannot be understood only after the rotor assembly is assembled by screwing. For this reason, there is a problem in that, for example, when the thrust pressure is insufficient and adjustment is required after assembly, the screw set rotor assembly must be disassembled for this adjustment.

Further, in the above-described conventional structure, since the shape of the thrust spring is complicated, it is difficult to match the spring characteristics (particularly the spring pressure) to a desired theoretical value, and the spring is used in processing steps such as material and heat treatment. The characteristics tend to change, and the spring pressure is greatly deteriorated during assembly and during use of the motor. And this may cause the thrust pressure to change, resulting in poor performance of the motor.

An object of the present invention is to provide a brushless motor in which the thrust pressure can be easily adjusted after assembling and the thrust pressure can be made stable and balanced.

[0009]

[Means for Solving the Problems]

 In the brushless motor of the present invention, a bearing set that rotatably supports the rotating shaft is provided on the outer periphery of the rotating shaft, the stator set is fixed to the bearing set, and a retaining member is provided on both sides of the rotating shaft in the axial direction. In the brushless motor, the thrust receiving washer is provided on the rotary shaft between at least one of the retaining members and the bearing assembly, and a part of the retaining portion is provided on the bearing assembly side. And thrusting the thrust washer toward the bearing assembly side in the axial direction.

The thrust washer may be pressed by the protrusion via a thrust spring, or may be directly pressed by the protrusion.

Further, the protruding portion is formed, for example, by bending a part of the retaining portion to the bearing assembly side.

[0012]

[Action]

 In the brassless motor of the present invention having the above-described structure, the thrust washer is pressed against the bearing assembly side by the protrusion provided on the retaining portion to generate thrust pressure that absorbs play in the thrust direction. Further, the pressing force of the bearing assembly by the thrust washers can be easily adjusted by changing the degree of protrusion of the protrusion with an appropriate jig in the assembled state of the motor. Therefore, even after the motor is assembled, the thrust pressure can be adjusted without disassembling the rotor set with screws.

Further, the thrust washer described above can be made into a simple shape with little change or deterioration over time in the working process and with spring characteristics in which elastic force is balanced. Therefore, the thrust pressure can be made stable and well balanced.

[0014]

【Example】

 Embodiments of a brushless motor according to the present invention will be described below with reference to the drawings.

1 to 3, the brushless motor of this embodiment is a brushless core-equipped motor including a rotor set 10, a stator set 20, a bearing set 30, and the like. The rotor set 10 includes a rotor case 11 and a drive magnet 12 fixed inside the rotor case 11. The stator set 20 includes a substrate 21 on which various electric element components and a core winding set 22 are mounted. The bearing assembly 30 includes a bearing 31 that rotatably supports a spindle (rotary shaft) 40, and a bearing holder 32 that is integrally fixed to the outer periphery of the bearing 31.

The rotor case 11 of the rotor set 10 is inserted into one end of the spindle (rotating shaft) 40 and fixed to the rotating shaft 40 by screwing, and at the other end of the rotating shaft 40. The hub 50 is joined and fixed to the hub 50 by press fitting or the like, whereby the rotating shaft 40 is held so as not to be detachable in the axial direction. The rotor case 11 (rotor group 10) and the hub 50 described above constitute a retaining portion in this embodiment.

As shown in FIG. 2 (a), a thrust washer 61 on which the bearing 31 rotates and a thrust spring 60 are sequentially inserted between the lower end portion of the bearing 31 in FIG. 1 and the rotor case 11. ing. The thrust washer 61 and the thrust spring 60 are, for example, as shown in FIG. 4, formed by punching an elastic flat material into a disk shape. The thrust washer 61 is provided with a standing piece 61a formed by bending a part of its outer peripheral portion. Further, the thrust spring 60 is provided with a groove 60a formed by cutting off a part of the outer peripheral portion of the thrust spring 60, into which the standing piece 61a is fitted. When the thrust spring 60 and the thrust washer 61 are overlapped with each other in the assembled state of the motor, by fitting the upright piece 61a into the groove 60a, the thrust washer 61 and the thrust spring 60 can be rotated together.

At the center of the rotor case 11, as shown in FIG. 3, a plurality of bent pieces 11a are formed in a substantially concentric shape. The bent piece 11a is formed by bending a part of a plane portion in the center of the rotor case by pressing. Further, the bending dimensions of these bent pieces 11a are appropriately set so that there is no thrust play in the brushless motor assembled state.

The assembling procedure of the brushless motor of the embodiment having the above configuration will be described with further reference to FIGS. First, the bearing set 30 is fixed to the stator set 20 by screwing or the like. Further, the spindle 40 is inserted into the bearing 31 of the bearing set 30, and the hub 50 is fixed to the spindle 40 on the back surface side (top surface side in FIGS. 4 and 5) of the substrate 21.

Next, the thrust washer 61 and the thrust spring 60 are sequentially assembled on the upper side of the spindle 40 in FIG. 4 so that the standing piece 61a is fitted in the groove 60a. Further, the rotor set 10 is attached to the upper surface side of the thrust spring 60. Finally, the screw 41 is fastened to the tap formed at the center of the spindle 40 through the hole provided at the center of the rotor case 11. This completes the work and assembly of the brushless motor.

In the thrust pressure inspection after the above assembly, if the thrust pressure is, for example, less than the designated pressure, the bent portion 11a of the rotor case 11 is required as shown in FIG. 2B, for example. The bearing 31 is further displaced by that amount.

In this case, the bent portion 11a is displaced by punching 80 on the upper surface side of the rotor case 11 with the spindle 40 and the hub 50 held by an appropriate receiving stand 70, as shown in FIG. The bent portion 11a of the rotor case 11 may be pressed by a plurality of claws 81 provided on the punch 80 to be further bent and pushed and deformed.

Then, due to the deformation of the bent portion 11a, the elastic force applied from the thrust spring 60 to the thrust washer 61 increases, and the thrust pressure increases. Therefore, even if a defect occurs, it is possible to adjust the thrust pressure without disassembling and easily correct it.

In addition, various design items can be changed without departing from the scope of the present invention. For example, as shown in FIG. 6, the thrust receiving washer 61 may be directly pressed by the bent portion 11a provided in the rotor case 11 without using the thrust spring 60 as in the above embodiment.

[0025]

[Effect of device]

 With the brushless motor of the present invention configured as described above, the thrust pressure can be easily adjusted while the motor is assembled. Therefore, there is no need to disassemble even if the thrust pressure is defective. In addition, the thrust pressure is generated from the protruding portion provided on the retaining portion through the thrust washer, and the thrust washer can have a simple shape in which its elastic force is easy and has well-balanced characteristics. Thrust pressure can be stable and well-balanced. Furthermore, since it is possible to save the labor of processing the thrust spring into a complicated shape as in the conventional case, there is an advantage that the cost can be reduced accordingly.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a brushless motor according to the present invention.

2A is an enlarged view of a portion A in FIG. 1, and FIG.
FIG. 6A is an explanatory view of a state where the bent portion of the rotor case is further bent from the state of (a).

FIG. 3 is an explanatory diagram of a rotor case used in the above embodiment.

FIG. 4 is an exploded perspective view of the above embodiment.

FIG. 5 is an explanatory diagram of a case where the thrust pressure is adjusted by a jig after assembly in the above-described embodiment.

FIG. 6 is a cross-sectional view of an essential part showing another embodiment of the present invention.

FIG. 7 is a sectional view showing a conventional example of a brushless motor.

FIG. 8 is a perspective view of a thrust spring used in the above conventional example.

[Explanation of symbols]

 10 rotor set 11 rotor case 20 stator set 22 core winding set 30 bearing set 31 bearing 40 spindle 50 hub 60 thrust spring 61 thrust washer

Claims (5)

[Scope of utility model registration request] 1. A bearing set for rotatably supporting the rotary shaft is provided on the outer circumference of the rotary shaft, a stator set is fixed to the bearing set, and retaining members are fixed to both sides of the rotary shaft in the axial direction. In at least one of the retaining members and the bearing assembly, a brushless motor is provided with a thrust washer on the rotating shaft, and a part of the retaining portion is projected toward the bearing assembly side. A brushless motor characterized in that the thrust washer is pressed toward the bearing assembly side in the axial direction by the protruding portion. 2. The brushless motor according to claim 1, wherein the thrust washer is pressed by the protrusion via a thrust spring. 3. The brushless motor according to claim 1, wherein the thrust washer is pressed by the protrusion. 4. The brushless motor according to claim 1, wherein the protruding portion is formed by bending a part of the retaining portion toward the bearing assembly side. 5. The brushless motor according to claim 1, wherein the retaining portion on which the protrusion is formed is a rotor case.