1. Field of Invention
The invention relates to a motor and a bearing structure thereof and, in particular, to a motor that can overcome the element and assembling errors and a bearing structure thereof.
2. Related Art
Motors have been widely used in electronic devices. As the electronic devices become smaller, the sizes of motors are also reduced while their speeds are increased. Therefore, how to reduce vibrations and noises during high-speed operations is an important issue of the motor.
As shown in
As described above, the cover element 302 only provides the axial stop. Since the sleeve 21 and the cover element 302 interfere with each other, the inner diameters of the bearing 301 and the cover element 302 may shrink so that they may touch the shaft 101. Moreover, even though the use of the adhesive provides the cover element 302 with an anti-torque, its effect varies with the material or the operation environment.
It is therefore an important subject of the invention to provide a motor and the bearing structure thereof to solve the above-mentioned problems. The invention can overcome the element and assembling errors, so that the shaft keeps an appropriate distance from the bearing or the cover element. This can reduce possible vibrations and noises during high-speed operations of the motor.
In view of the foregoing, the invention is to provide a motor and a bearing structure thereof that can overcome the element and assembling errors.
To achieve the above, a bearing structure according to the invention, which is coupled to a shaft, includes a bearing and a cover element. The bearing is coupled to the shaft. The cover element is held to the bearing and covers at least one portion of one end of the bearing. The cover element includes a turning portion that has a groove.
In this aspect, the cover element has a first part and a second part. The turning portion is located at the joint between the first part and the second part. The first part has at least a buffer structure for contacting to a side-surface of the bearing.
To achieve the above, a motor of the invention includes a rotor structure, a stator structure, and a bearing structure. The rotor structure includes a hub and a shaft connected to the hub. The stator structure has a shaft hole, and the shaft is disposed in the shaft hole. The bearing structure has a bearing and a cover element. The bearing is disposed in the shaft hole and coupled to the shaft. The cover element urges against the bearing and covers at least one portion of one end of the bearing. The cover element includes a turning portion that has a groove.
In the aspect, the cover element has a first part and a second part. The turning portion is located at the joint between the first part and the second part. The first part has at least a buffer structure for contacting to a side-surface of the bearing.
The rotor structure further includes a first magnetic device and a second magnetic device, which are respectively disposed on the inner-surface of the hub and the cover element in the opposite positions.
As mentioned above, the motor and the bearing structure thereof of the invention use the cover element in the bearing structure to cover one end of the bearing so as to form a turning portion. The turning portion has a groove as a buffer region to alleviate the radial shrinking of the cover element by shrinking of the shaft hole. This prevents the cover element from shrinking its inner diameter to touch the shaft. In other words, this feature of the invention can reduce the gap error between the cover element and the shaft. Moreover, one part of the cover element has at least one buffer structure for contacting to the side-surface of the bearing. The buffer structure provides the bearing with an anti-torque effect and a buffering effect to overcome the device and assembling errors. In comparison with the prior art, the invention also overcomes worries of a varying anti-torque of the bearing as a result of the adhesive under material and environmental changes. In addition, the buffer structure touches the bearing by a small area. The possibility of a shrinking inner diameter in the bearing structure is effectively reduced. Therefore, the cover element of the invention can indeed overcome the device and assembling errors. Moreover, the first magnetic device and the second magnetic device secure the positioning of the bearing structure, which can reduce the vibrations and noises during high-speed operations of the motor.
The invention will become more filly understood from the detailed description given herein below illustration only, and thus is not limitative of the present invention, and wherein:
The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.
With reference to
The rotor structure 40 includes a hub 401 and a shaft 402. The shaft 402 is connected to the hub 401. As shown in
As described above, the inner surface of the hub 401 is provided in sequence with a magnetic conductive shell 403 and a magnet 404. The magnetic conductive shell 402 is a metal chip. The magnet 404 can be a permanent magnet. In this embodiment, the magnetic conductive shell 403 and the magnet 404 have an annular structure disposed on the inner side of the hub 401.
The rotor structure 40 may further include a shell 80 connected to the outer surface of the hub 401. The shell 80 has several blades 801. The blades 801 rotate with the rotor structure 40 driven by the stator structure 50.
The stator structure 50 has a sleeve 51, a stator pole 52, and a circuit board 53. The sleeve 51 has a shaft hole 501, and the shaft 402 is disposed in the shaft hole 501 of the sleeve 51. An abrasion resistant pad 405 is coupled to one end of the shaft 402. The stator pole 52 is formed by a wound coil and disposed opposite to the magnet 403. Through the magnetic interaction between the stator pole 52 and the magnet 403, the rotor structure 40 and the stator structure 50 produce a relative motion. The circuit board 53 is mounted on the outer side of the sleeve 51 and has a sensor to detect and control the magnetic field of the stator structure 50.
The bearing structure 60 has a bearing 601 and a cover element 602. The bearing 601 is disposed in the shaft hole 501 and coupled to the shaft 402. The bearing 601 can be a ball bearing, a self-lubricating bearing, a fluid dynamic bearing, or a sleeve bearing. The cover element 602 urges against the top-surface and/or the side-surface of the bearing 601 and covers at least a portion of one end of the bearing 601. In this embodiment, the cover element 602 is a U-shaped cover element, an L-shaped cover element or a cap-shaped cover element.
Furthermore, as shown in
The surface of the cover element 602 facing the shaft 402 has at least one guiding angle 6026. In this embodiment, the guiding angle 6026 is formed on the upper portion of the surface of the cover element 602 that faces the shaft 402. The guiding angle 6026 can be a fillet angle, an arc angle, a tilted angle, or a polygonal angle. As described above, since the guiding angle 6026 has a smaller contact area when a pressure is imposed against the radial action in comparison with a cover element without a guiding angle, the friction between the cover element 602 and the shaft 402 is greatly reduced. Also, as the upper pressure on the surface of the cover element 602 that faces the shaft 402 is larger than the lower pressure due to the guiding angle 6026, it has the function of preventing the lubricant oil filled between the bearing 601 and the shaft 402 from leaking.
The motor 4 according to the preferred embodiment of the invention further includes f first magnetic device 71 and a second magnetic device 72. The first magnetic device 71 is disposed on the inner surface of the hub 401, and the second magnetic device 72 is disposed on the cover element 602 and opposite to the first magnetic device 71. The first magnetic device 71 and the second magnetic device 72 are magnets, electromagnets, or magnetic conductive devices such as iron or silicon steel plates. For example, the first magnetic device 71 can be a magnet or electromagnet, while the second magnetic device 72 can be a magnetic conductive device such as an iron or silicon steel plate. Of course, the first magnetic device 71 may be a magnetic conductive device, while the second magnetic device 72 is a magnet or electromagnet. Besides, the first magnetic device 71 and the second magnetic device 72 can both be magnets or electromagnets. Using the above-mentioned combination, the cover element 602 and the hub 401 can be fixed by the magnetic field to a position. It is thus prevented from touching the shaft 402 due to a shrinking inner diameter.
In summary, the motor and the bearing structure thereof of the invention use the cover element in the bearing structure to cover one end of the bearing so as to form a turning portion. The turning portion has a groove as a buffer region to alleviate the radial shrinking of the cover element by shrinking of the shaft hole. This prevents the cover element from shrinking its inner diameter to touch the shaft. In other words, this feature of the invention can reduce the gap error between the cover element and the shaft. Moreover, one part of the cover element has at least one buffer structure for contacting to the side-surface and/or the top-surface of the bearing. The buffer structure provides the bearing with an anti-torque effect and a buffering effect to overcome the device and assembling errors. In comparison with the prior art, the invention also overcomes worries of a varying anti-torque of the bearing as a result of the adhesive under material and environmental changes. In addition, the buffer structure touches the bearing by a small area. The possibility of a shrinking inner diameter in the bearing structure is effectively reduced. Therefore, the cover element of the invention can indeed overcome the device and assembling errors. Moreover, the first magnetic device and the second magnetic device secure the positioning of the bearing structure, which can reduce the vibrations and noises during high-speed operations of the motor.
Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the invention.
Number | Date | Country | Kind |
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094134270 | Sep 2005 | TW | national |