Patent Application
20090004010
This application claims the benefit of priority based on Chinese Patent Application Serial No. ______, filed 4 Jun. 2007, the contents of which are herein incorporated by reference.
1. Field of the Invention
The present invention relates to a signal transmission apparatus of a DC brushless motor. More particularly, the present invention relates to a signal transmission apparatus used in a DC brushless motor of a ceiling fan for transmitting at least one processed output signal from at least one sensor, wherein the output signal represents a variation of the magnetic pole operations in the DC brushless motor.
2. Descriptions of the Related Art
DC brushless motors have several advantages, such as a high torque at low speeds and low electromagnetic interference. In addition, they are free of noise and carbon brush maintenance. However, to successfully start and maintain smooth operation of a DC brushless motor from its stationary state, the sensors (e.g., Hall sensor) have to be mounted in the motor to sense the variation of the magnetic fields from the rotation of the magnets. The motor control signal can then be generated to ensure continuous and steady operation of the motor.
For example, in a three-phase DC brushless motor, three sensors and a permanent magnet are required.
Drilling is required to route the transmission lines between the motor and the controller. However, this is an invasive process that often ends in hardware damage. For example, to mount the three-phase DC brushless motor to the ceiling fan, large connecting holes have to be drilled into the motor axis so that the transmission lines can pass therethrough and connect to the controller. These large connecting holes may degrade the durability of the motor axis, and consequently, place the user at risk for injury after a long period of service.
One objective of this invention is to provide a signal transmission apparatus of a DC brushless motor for a ceiling fan, in which the output signal from a sensor is transmitted to a controller via one transmission line. As a result, the number of connecting lines is reduced from five to two. The two connecting lines are the transmission line and reference voltage level line. In this way, the eventual degradation of the motor axis due to excessively large connecting holes is prevented.
Through the combination of a plurality of output signals from the respective sensors in this invention, the output signals can be transmitted from the sensors mounted in the motor to a controller through just one transmission line. Thus, the number of transmission lines is reduced without affecting the data of such output signals, and therefore. Usage of line materials can be reduced effectively.
The detailed technology and preferred embodiments implemented for the subject invention are described in the following paragraphs accompanying the appended drawings for people skilled in this field to well appreciate the features of the claimed invention.
The main concept of this invention is to achieve signal transmission in a DC brushless motor of a ceiling fan using a sequenced signal transmission technology. The following descriptions will be made in reference to the preferred embodiment.
The sensors 55, 56 and 57 are configured to sense the variation of the magnetic fields as a function of the relative angles of the magnet 51 with respect to the excitation coils 52, 53 and 54, and to generate the output signals 551, 561 and 571 respectively. The output signals 551, 561 and 571 are transmitted to the signal processor 71 of the signal transmission apparatus 7. The output signals 551, 561 and 571 represent the variation of the rotating magnetic poles in the DC brushless motor 5. The signal processor 71 supplies power to the sensor 55 via a coil-energizing line 552, and also supplies a reference voltage level via a reference voltage level line 553. Similarly, the signal processor 71 is not only electrically connected to the sensor 56 via the coil-energizing line 562 and reference voltage level line 563, but also electrically connected to the sensor 57 via the coil-energizing line 572 and reference voltage level line 573.
Upon receiving the output signals 551, 561 and 571, the signal processor 71 processes these output signals into a sequenced signal 721, so that the processed output signals can be transmitted collectively through the single transmission line 72. The sequenced signal 721 is transmitted via the transmission line 72 to the signal restorer 61, which restores the sequenced signal 721 back into the output signals 551, 561 and 571 for use by the controller 6 in operating the DC brushless motor 5. In detail, based on the restored output signals 551, 561 and 571 received from the signal restorer 61, the controller 6 executes a sequence of power adjustment procedures and generates power signals 612, 613 and 614 to the excitation coils 52, 53 and 54 of the motor 5, respectively, through the coil-energizing lines 62, 63 and 64, thereby, controlling the operation of the DC brushless motor 5.
Furthermore, as illustrated in
In this embodiment, the processed output signals 551, 561 and 571 are transmitted through the transmission line 72, and can be restored upon reception by the signal restorer 61, so that the controller 6 can adjust the power signals 612, 613 and 614 outputted to the excitation coils 52, 53 and 54 based on the restored output signals 551, 561 and 571, thereby, controlling the operation of the DC brushless motor 5.
In the above embodiment, the controller 6 can be arranged at any appropriate location. For example, the controller 6 can be arranged inside the housing, such as a bell-shaped housing, at the interface between the ceiling fan 1 and the ceiling.
It should be emphasized that the output signals 551, 561 and 571 in this invention are transmitted collectively through a single transmission line 72, and therefore no additional transmission lines are required for transmitting the output signals of the sensors.
It should be appreciated from the above descriptions that, this invention can be used in a DC brushless motor of a ceiling fan to transmit output signals of sensors via a single transmission line in a processing-and-restoring way to reduce the number of transmission lines used and eliminate the need of excessively large holes in the motor axis. As a result the axis endurance is maintained and prolongs the service life of the motor, and reducing the replacement cost and time.
The above disclosure is related to the detailed technical contents and inventive features thereof. People skilled in this field may proceed with a variety of modifications and replacements based on the disclosures and suggestions of the invention as described without departing from the characteristics thereof. Nevertheless, although such modifications and replacements are not fully disclosed in the above descriptions, they have substantially been covered in the following claims as appended.
