Motor controller for a sunshade assembly

A motor controller includes a signal-generating unit that is operable so as to control rotational direction and rotational speed of a motor of a sunshade assembly, and a processing unit that operates the signal-generating unit to rotate the motor in a reverse direction to thereby retract a flexible screen body of the sunshade assembly, and to generate a decelerating signal for progressively reducing the rotational speed of the motor during a final stage of retraction of the flexible screen body.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a motor controller, more particularly to a motor controller for a sunshade assembly.

2. Description of the Related Art

An electric sunshade assembly is generally employed for covering a windshield of an automobile. The conventional electric sunshade assembly includes a base, a flexible screen body, and a batten provided on a free end of the flexible screen body.

The aforementioned conventional electric sunshade assembly is disadvantageous in that when the flexible screen body is retracted, since the flexible screen body is retracted at a relatively high speed, a considerable noise is generated due to collision between the batten and the base, as illustrated inFIG. 3. Moreover, the conventional electric sunshade assembly is designed for use in a tropical or sub-tropical zone. As such, when the conventional electric sunshade assembly is used in frigid zones, the conventional electric sunshade assembly may operate abnormally or fail to operate.

SUMMARY OF THE INVENTION

Therefore, the main object of the present invention is to provide a motor controller for a sunshade assembly that can overcome the aforesaid drawbacks of the prior art.

According to the present invention, a motor controller for a sunshade assembly comprises a judging unit, a recording unit, a signal-generating unit, and a processing unit. The sunshade assembly includes a flexible screen body, a mechanism that is operable so as to extend or retract the flexible screen body, a motor for controlling the mechanism, a first manually actuated switch assigned with a function to extend the flexible screen body, and a second manually actuated switch assigned with a function to retract the flexible screen body. The judging unit is adapted to be coupled to the first and second manually actuated switches, and is operable so as to determine a currently actuated one of the first and second manually actuated switches, and so as to generate a function signal indicative of the function assigned to the currently actuated one of the first and second manually actuated switches determined thereby. The recording unit is coupled to the judging unit, and stores therein a function message indicative of the function assigned to a previously actuated one of the first and second manually actuated switches. The signal-generating unit is adapted to be coupled to the motor, and is operable so as to control rotational direction and rotational speed of the motor. The processing unit is coupled to the judging unit, the recording unit, and the signal-generating unit, and is operable so as to determine whether the function signal generated by the judging unit matches the function message stored in the recording unit. When it is determined that the function signal does not match the function message, the processing unit operates the signal-generating unit to rotate the motor in a direction based on the function assigned to the currently actuated one of the first and second manually actuated switches. The processing unit further operates the signal-generating unit to generate a decelerating signal for progressively reducing the rotational speed of the motor during a final stage of retraction of the flexible screen body.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring toFIG. 1, the preferred embodiment of a motor controller3according to the present invention is shown to include a judging unit31, a recording unit32, a signal-generating unit34, and a processing unit33.

The motor controller3of this invention is mounted on a sunshade assembly.

The sunshade assembly is installed in an automobile (not shown), and includes a flexible screen body (not shown), a mechanism (not shown) that is operable so as to extend or retract the flexible screen body, a batten (not shown) provided on a free end of the flexible screen body, a motor101that drives operation of the mechanism, a first manually actuated switch102that is assigned with a function to extend the flexible screen body and that is actuated when pressed by a user (not shown), a second manually actuated switch103that is assigned with a function to retract the flexible screen body and that is actuated when pressed by the user (not shown), an automatically actuated switch104that is assigned with a function to retract the flexible screen body and that is actuated when a transmission of the automobile is shift to reverse, and a power supply100connected to the motor controller3.

The judging unit31is connected to the first and second manually actuated switches102,103and the automatically actuated switch104, and is operable so as to determine a currently actuated one of the first and second manually actuated switches102,103and the automatically actuated switch104, and so as to generate a function signal indicative of the function assigned to the currently actuated one of the first and second manually actuated switches102,103and the automatically actuated switch104.

The recording unit32is connected to the judging unit31, and stores therein a function message indicative of the function of a previously actuated one of the first and second manually actuated switches102,103and the automatically actuated switch104.

The signal-generating unit34is connected to the motor101, and is operable so as to control rotational direction and rotational speed of the motor101, in a manner that will be described hereinafter.

The processing unit33is connected to the judging unit31, the recording unit32, and the signal-generating unit34, and is operable so as to determine whether the function signal generated by the judging unit31matches the function message stored in the recording unit32. When it is determined that the function signal does not match the function message, the processing unit33operates the signal-generating unit34to rotate the motor101in a direction based on the function assigned to the currently actuated one of the first and second manually actuated switches102,103and the automatically actuated switch104. In this embodiment, the processing unit33operates the signal-generating unit34to generate an accelerating signal for progressively increasing the rotational speed of the motor101, e.g., from zero to a predetermined value, during an initial stage of extension/retraction of the flexible screen body. Moreover, in this embodiment, the processing unit33operates the signal-generating unit34to generate a decelerating signal for progressively reducing the rotational speed of the motor101, e.g., from the predetermined value back to zero, during a final stage of the extension/retraction of the flexible screen body. Further, in this embodiment, the processing unit33operates the signal-generating unit34to generate a constant signal for maintaining the rotational speed of the motor101constant, e.g., at the predetermined value, during an intermediate stage between the initial and final stages of the extension/retraction of the flexible screen body.

It is noted that signal-generating unit34is constituted by a plurality of metal oxide semiconductor field effect transistors (MOSFETs). The rotational speed of the motor101is controlled by varying a duty cycle of the signal-generating unit34to thereby adjust an operating effective current for driving the motor101.

The motor controller3further includes a current detector35and a temperature sensor36. The current detector35is connected to the signal-generating unit34and the processing unit33, and is operable so as to detect an output current of the signal-generating unit34, and so as to generate an output signal indicative of the output current detected thereby.

The processing unit33is further operable so as to determine whether the output signal generated by the current detector35exceeds a threshold value. When it is determined that the output signal generated by the current detector35exceeds the threshold value, the processing unit33stops operation of the signal-generating unit34and the motor controller3, thereby preventing the motor101and the motor controller3from being damaged.

The temperature sensor36is connected to the processing unit33, and is operable so as to detect the ambient temperature, and so as to generate an output signal indicative of the ambient temperature detected thereby.

The processing unit33is further operable so as to adjust an operating current of the motor controller3and the threshold value based on the output signal generated by the temperature sensor36. The construction as such ensures normal operation of the motor controller3under different ambient temperatures.

The preferred embodiment of a method to be implemented using the aforementioned motor controller3according to this invention will now be described with further reference toFIGS. 2A to 2C.

In step1, the processing unit33adjusts the operating current of the motor controller3and the threshold value based on the output signal generated by the temperature sensor36.

In step2, the processing unit33enters a sleep mode.

In step3, the judging unit31determines whether the first manually actuated switch102is actuated.

In step4, when it is determined in step3that the first manually actuated switch102is actuated, the flow proceeds to step5. Otherwise, the flow proceeds to step10.

In step5, the judging unit31generates a function signal indicative of the function assigned to the first manually actuated switch102.

It is noted that the function signal generated in this step wakes the processing unit33up from the sleep mode.

In step6, the processing unit33determines whether the function signal generated in step5matches the function message stored in the recording unit32.

In step7, when it is determined in step6that the function signal does not match the function message, which indicates that the flexible screen body is in a retracted state, the flow proceeds to step8. Otherwise, i.e., the function signal matches the function message, which indicates that the flexible screen body is in an extended state, the flow goes back to step2.

In step8, the processing unit33operates the signal-generating unit34to rotate the motor101in a forward direction to thereby extend the flexible screen body.

In step9, the processing unit33operates the signal-generating unit34to generate the accelerating signal, the constant signal, and the decelerating signal during the first twenty-five percent, the next fifty percent, and the last twenty-five percent, respectively, of the duration of the extension of the flexible screen body. Thereafter, the flow is terminated.

In step10, the judging unit31determines whether the second manually actuated switch103is actuated.

In step11, when it is determined in step10that the second manually actuated switch103is actuated, the flow proceeds to step12. Otherwise, the flow proceeds to step17.

In step12, the judging unit31generates a function signal indicative of the function assigned to the second manually actuated switch103.

It is noted that the function signal generated in this step wakes the processing unit33up from the sleep mode.

In step13, the processing unit33determines whether the function signal generated in step12matches the function message stored in the recording unit32.

In step14, when it is determined in step13that the function signal does not match the function message, which indicates that the flexible screen body is in the extended state, the flow proceeds to step13. Otherwise, i.e., the function signal matches the function message, which indicates that the flexible screen body is in the retracted state, the flow goes back to step2.

In step15, the processing unit33operates the signal-generating unit34to rotate the motor101in a reverse direction to thereby retract the flexible screen body.

In step16, the processing unit33operates the signal-generating unit34to generate the accelerating signal, the constant signal, and the decelerating signal during the first twenty-five percent, the next fifty percent, and the last twenty-five percent, respectively, of the duration of the retraction of the flexible screen body. Thereafter, the flow is terminated.

In step17, the judging unit31determines whether the automatically actuated switch104is actuated.

In step18, when the judging unit31determines that the automatically actuated switch104is actuated, the flow proceeds to step19. Otherwise, the flow goes back to step2.

In step19, the judging unit31generates a function signal indicative of the function assigned to the automatically actuated switch104.

It is noted that the function signal generated in this step wakes the processing unit33up from the sleep mode.

In step20, the processing unit33determines whether the function signal generated in step19matches the function message stored in the recording unit32.

In step21, when it is determined in step20that the function signal does not match the function message, which indicates that the flexible screen body is in the extended state, the flow proceeds to step22. Otherwise, i.e., the function signal matches the function message, which indicates that the flexible screen body is in the retracted state, the flow goes back to step2.

In step22, the processing unit33operates the signal-generating unit34to rotate the motor101in the reverse direction to thereby retract the flexible screen body.

In step23, the processing unit33operates the signal-generating unit34to generate the accelerating signal, the constant signal, and the decelerating signal during the first twenty-five percent, the next fifty percent, and the last twenty-five percent, respectively, of the duration of the retraction of the flexible screen body. Thereafter, the flow is terminated.

From the above description, when the mechanism is operated to retract the flexible screen body, since the motor controller3of the present invention progressively reduces the rotational speed of the motor101the during the final stage of the retraction of the flexible screen body, noise generated due to collisions among the batten, the mechanism, and other components, such as a base, of the sunshade assembly is significantly suppressed, as illustrated inFIG. 3.