JPH0223087Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Objective of the Invention] (Field of Industrial Application) The present invention relates to an axial gap type motor in which a rotor is disposed axially opposite to a stator via an air gap.

(Prior art) Traditionally, this type of motor was
There is one shown in Publication No. 115283. As shown in FIG. 2, a pair of rolling bearings 2 and 3 are provided at the center of the base 1, a rotating shaft 4 is supported by the rolling bearings 2 and 3, and a rotor magnet 5 is mounted on the rotating shaft 4. The rotor 6 is attached to the stator 7 through a gap in the axial direction. In this case, each outer race 2a, 3a of each rolling bearing 2, 3 is held on the base 1, and each inner race 2b, 3b is fitted in the upper and lower positions of the rotating shaft 4, and each rolling bearing 2, 3 To prevent end play caused by rattling,
The rotating shaft 4 is formed into a two-stage stepped shape, with the large diameter portion 4a of the rotating shaft 4 touching the inner race 2b of the upper rolling bearing 2, and the intermediate diameter portion 4b and the inner race 3b of the lower rolling bearing 3. A coil spring 8 is provided between the two.

(Problem to be solved by the invention) In this configuration, the magnetic attraction force generated by the rotor magnet 5 is used to apply downward pressure from the rotating shaft 4 to the inner race 2b of the rolling bearing 2 located on the upper side. On the other hand, the lower rolling bearing 3
Pressure is applied to the inner race 3b by a coil spring 8 provided between the inner race 3b and the intermediate diameter portion 4b. However, in this type of motor, since the stator coils 9 are disposed intermittently in the circumferential direction, the magnetic attraction force acting on the rotor magnet 5 has a property that it fluctuates periodically as the rotor 6 rotates. For this reason, in the configuration in which the magnetic attraction force of the rotor magnet 5 is used to apply pressure to each inner race 2b, 3b, as described above, the pressurization force also fluctuates as the magnetic attraction force fluctuates, resulting in rotational rotation. End play of the shaft 4 cannot be reliably suppressed, which may lead to a decrease in rotation accuracy.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an axial gap type brushless motor that can reliably suppress end play of the rotating shaft and improve rotational accuracy.

[Structure of the invention] (Means for solving the problem) The axial gear brushless motor of the invention basically consists of a stator configured on a base and a pair of rollers provided on the base. A bearing, a rotating shaft rotatably supported by the bearing, a pair of pressurized annular bodies attached to the rotating shaft that apply pressure to the rolling bearing, and rotation via one of the pressurized annular bodies. The rotor is attached to the shaft and faces the stator in the axial direction via an air gap. Of these, each of the rolling bearings includes an outer race and an inner race, each of the outer races of the rolling bearing is held on a base, and each of the inner races is fitted to a rotating shaft, each of the pressurized annular bodies is screwed to the rotating shaft in a state where the inner races of each rolling bearing are biased toward each other, and the rotor consists of a rotor yoke and a rotor magnet attached to the rotor yoke, and the rotor yoke has an outer peripheral edge. The rotor yoke is shaped like a container with a peripheral wall formed therein and has a fitting hole in the center, and the rotor yoke is fixed to the rotating shaft by fitting the fitting hole into one of the pressurized annular bodies, and the rotor magnet The outer diameter of the rotor magnet is set to be smaller than the inner diameter of the peripheral wall of the rotor yoke, and the rotor magnet has a gap between it and the inner peripheral surface of the peripheral wall of the rotor yoke for filling putty for correcting imbalance. It is unique in that it is fixed to the rotor yoke with a portion left over.

(Function) According to the above means, since the bearing is pressurized by the pressurized annular body screwed to the rotating shaft, pressurization can be stably applied without being affected by fluctuations in magnetic attraction force, etc. It is possible to improve the rotational accuracy.

However, when the pressurized annular body is attached to the rotating shaft with screws as in the above method,
On the other hand, it also has the disadvantage that the center of gravity tends to be eccentric. This is because the fixing screws of each pressurized annular body are in eccentric positions, and these are not necessarily in symmetrical positions when the pressurized annular bodies are installed. Regarding this point, in the above means, the outer diameter of the rotor magnet is set to be smaller than the rotor yoke to leave a gap between it and the rotor yoke for filling the putty for correcting the imbalance. Even if an eccentric center of gravity occurs, it can be reliably corrected by installing the pressurized annular body, thereby reliably suppressing the decline in rotational accuracy due to an eccentric center of gravity, and further improving rotational accuracy by ensuring pressurization is applied. can be achieved.

(Example) An example of the present invention will be described below with reference to FIG. 1.

Reference numeral 1 designates a base for constructing the stator 2. A through hole 1a is formed approximately in the center of the base 1, and a pair of rolling bearings 3, 4 are provided at both upper and lower ends of the through hole 1a. Both of these rolling bearings 3 and 4 consist of annular inner races 3a and 4a and outer races 3b and 4b, and the outer races 3 and
b, 4b are held in a fitted state above and below within the through hole 1a. 5 is a stator yoke fixed to the base 1, 6 is a stator board stacked on the stator yoke 5, and 7 is a plurality of stator coils arranged intermittently in the circumferential direction on the stator board 6.

In the stator 2 configured as above, 8 is a rotating shaft, which is fitted into each of the inner races 3a, 4a of the rolling bearings 3, 4, and is rotatably supported through the base 1. There is. Reference numeral 9 denotes a lower pressurized annular body attached to the rotating shaft 8, which is screwed to the rotating shaft 8 in a state that urges the inner race 4a of the rolling bearing 4 upward. On the other hand, 10 is also an upper pressurized annular body attached to the rotating shaft 8, and this is screwed to the rotating shaft 8 in a state that urges the inner race 3a of the rolling bearing 3 downward. As a result, the inner races 3a and 4a of the rolling bearings 3 and 4 are urged toward each other, and the inner races 3a and 4a of the rolling bearings 3 and 4 are urged toward each other.
Shaking is prevented and end play of the rotating shaft 8 is regulated. In addition, the upper pressurized annular body 10
A connecting cylindrical portion 10a, which is slightly lower in depth than the depth of a concave portion at the center of the rotor yoke, which will be described later, is integrally protruded from the upper end.

A rotor 11 faces the stator 2 in the axial direction via an air gap, and is composed of a rotor yoke 12 and a rotor magnet 16. The rotor yoke 12 is formed, for example, by pressing an iron plate, and has a container shape with a peripheral wall 13 formed on the outer periphery, and has a lower part located approximately at the center (the stator 2
A circular recess 14 is formed in the center of the recess 14, and a fitting hole 15 having an inner diameter substantially the same as the outer diameter of the connecting cylinder portion 10a of the upper pressurized annular body 10 is formed in the center of the recess 14. Further, the rotor magnet 16 has an outer diameter smaller than the inner diameter of the peripheral wall 13 of the rotor yoke 12 and a larger inner diameter than the outer diameter of the recess 14 of the rotor yoke 12. It is fixed to the rotor yoke 12 by, for example, adhesive, with double annular gaps 17 and 18 left between the side and the rotor yoke 12 on the inner peripheral side. Incidentally, reference numeral 19 denotes a chamfered portion formed on the inner peripheral portion of the magnetized surface (lower surface) side of the rotor magnet 16, and this is for identifying the magnetized surface when the rotor magnet 16 is attached. The rotor 11 configured in this manner is fixed to the pressurized annular body 10 by fitting the fitting hole 15 of the rotor yoke 12 to the outside of the connecting cylinder portion 10a of the upper pressurized annular body 10 and tightening the screw 20. It is adapted to rotate integrally with the rotating shaft 8. A balancing putty 21 is embedded in the outer gap 18 on the side opposite to the eccentric center of gravity in order to correct the eccentric center of gravity of the rotor 11.

According to the above configuration, since the lower pressurized annular body 9 is biased upward and screwed, the inner race 4a of the lower rolling bearing 4 absorbs the upward margin with respect to the rotating shaft 8. and is in a fixed state. On the other hand, since the upper pressurized annular body 10 is biased downward and screwed, the inner race 3a of the upper rolling bearing 3 is fixed to the rotating shaft 8 by absorbing the downward allowance. in a state. As a result, the rotating shaft 8 is supported by each of the rolling bearings 3 and 4 without shaking in the axial direction. In this way, in the above embodiment, since the rolling bearings 3 and 4 are pressurized by the pressurized annular bodies 9 and 10 screwed to the rotating shaft 8, they are not affected by fluctuations in magnetic attraction force, etc. It is possible to stably apply pressurization to the rotor, thereby improving rotation accuracy.

In addition, when the pressurized annular bodies 9 and 10 are attached to the rotating shaft 8 by screws as in this embodiment, on the other hand, each pressurized annular body 9 and 10 at an eccentric position,
Since the fixing screws 10 are not necessarily in symmetrical positions when installing the pressurized annular body, rotor 1
1 also has the disadvantage that it tends to have an eccentric center of gravity.
However, in the present invention, the outer diameter of the rotor magnet 16 is set to be smaller than the inner diameter of the peripheral wall 13 of the rotor yoke 12, and a gap is created between the rotor magnet 16 and the rotor yoke 12 for filling the putty 21 for correcting the imbalance. 17, even if an eccentric center of gravity occurs due to the attachment of the pressurized annular bodies 9, 10, it can be reliably corrected. Moreover, the putty 21 embedded in the cavity 17 is
Since the putty 21 is located inside the peripheral wall 13 of the rotor 11, there is no risk that the putty 21 will peel off and fly away due to the strong centrifugal force that acts when the rotor 11 rotates, and the eccentric center of gravity can be reliably corrected. can.

Note that in order to correct the eccentric center of gravity, a part of the peripheral wall portion 13 of the rotor yoke 12 may be cut without using the putty 21 or in conjunction with the putty 21. Even if this is done, in this example,
Since the gap 17 exists between the peripheral wall portion 13 of the rotor yoke 12 and the rotor magnet 16, there is no risk of damaging the rotor magnet 16 when cutting the peripheral wall portion 13. Furthermore, especially as in this embodiment, a connecting cylindrical portion 10a is integrally provided on the pressurized annular body 10 for regulating end play, and this connecting cylindrical portion 10a
By fitting the rotor yoke 12 to the rotor yoke 12, there is no need to provide a dedicated boss body for fitting the rotor yoke 12, and the number of parts can be reduced. In addition, as in this embodiment, the rotor yoke 12
A recess 14 is depressed approximately in the center of the recess 14 .
If the upper end of the rotating shaft 7 is located inside the
The entire motor can be made thinner in the axial direction.

[Effects of the invention] As described above, the present invention has a structure in which the pressurized annular body for applying pressure to the bearing for supporting the rotating shaft is attached to the rotating shaft by screwing, so it is possible to use a coil spring or the like. Compared to a configuration in which pressurization is applied by means of a rotor, stable pressurization can be applied and rotation accuracy is improved. In addition, even if an eccentric center of gravity occurs due to the screws used to attach the pressurized annular body, since the rotor magnet is formed with a smaller diameter than the rotor yoke, the gap created between the two can be used to correct the imbalance. By embedding putty or the like, unbalance can be reliably corrected and higher rotation accuracy can be obtained, which is an excellent effect.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention, and FIG. 2 is a vertical sectional view showing a conventional example. In the drawing, 1 is a base, 2 is a stator, 3 and 4 are rolling bearings, 3a and 4a are inner races, 3
b, 4b is the outer race, 8 is the rotating shaft, 9, 1
0 is a pressurized annular body, 11 is a rotor, 12 is a rotor yoke, 13 is a peripheral wall, 14 is a recess, 15 is a fitting hole, 16 is a rotor magnet, 17 is a gap, 21
is putty.

Claims (1)

[Claims for Utility Model Registration] 1. A stator 2 configured on a base 1, a pair of rolling bearings 3 and 4 provided on the base 1,
A rotating shaft 8 rotatably supported by the rolling bearings 3 and 4, a pair of pressurizing annular bodies 9 and 10 attached to the rotating shaft 8 and applying pressurization to the rolling bearings 3 and 4, and this pressurizing Annular bodies 9, 10
a rotor 11 that is attached to the rotating shaft 8 through one of the rotary shafts and faces the stator 2 in the axial direction via an air gap; each of the rolling bearings 3, 4 has an inner race 3a, 4a; outer races 3b, 4b, each of the outer races 3b, 4b of the rolling bearings 3, 4 is held by the base 1, and each inner race 3a, 4a is fitted to the rotating shaft 8; The pressurized annular bodies 9 and 10 are screwed to the rotating shaft 8 in a state that urges the inner races 3a and 4a of the respective rolling bearings 3 and 4 toward each other, and the rotor 11 is screwed to the rotor yoke 12. The rotor yoke 12 has a peripheral wall portion 1 on its outer periphery.
The rotor yoke 12 is fixed to the rotating shaft 8 with the fitting hole 15 fitted into one of the pressurized annular bodies 9 and 10. The rotor magnet 16 has an outer diameter smaller than an inner diameter of the peripheral wall 13 of the rotor yoke 12, and the rotor magnet 16 has an inner peripheral surface of the peripheral wall 13 of the rotor yoke 12. Gap 17 for filling putty for unbalance correction between
The axial gear motor is fixed to the rotor yoke 12 with a portion left over. 2. Scope of Utility Model Registration Claims characterized in that a recess 14 is formed approximately in the center of the rotor yoke 12 and is recessed toward the stator 2, and the end of the rotating shaft 8 on the rotor 11 side is located within the recess 14. The axial gap type motor according to item 1.