Patent Application
20190194999
The present disclosure relates generally to a power back door of a vehicle that can be automatically driven by a pair of power back door drive devices, and is applicable to a hatchback-type back door or power lift gate.
Back doors or lift gates in the rear of motor vehicles are frequently opened and closed to place or remove items in the rear of the vehicle. The speed at which the back door or lift gate is opened requires that it must slow down near the full open position so that it does not bounce when it reaches the end of travel. The back door or lift gate may be slowed down as it approaches the end by reducing the speed of a power back door drive mechanism. However, reducing the speed causes the door to be slow to open. The slow opening speed leads to a sense of low quality, as well as being an inconvenience for the user. It would be preferable to remove the need to slow down the door near full open position and decrease the opening time, without the door bouncing as it reaches the end of travel.
The foregoing “Background” description is for the purpose of generally presenting the context of the disclosure. Work of the inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout several views, the following description relates to power back door drive devices for automatically opening and closing a power back door of a vehicle, including hatchback-type back doors or power lift gates.
The power back door drive device 150 includes a joint 151 for attaching to the vehicle body. The joint 151 is connected to an end of an inner tube 165. The inner tube 165 is surrounded by an outer tube 155 and may slide in and out of the outer tube. A spring 153 is also arranged inside the outer tube 155. The power back door drive device 150 may include a spindle nut 157 that screws over threads of a spindle screw 159. A planetary gear 161 may be integrated between the spindle screw 159 and the motor 163 to change the rotation speed of the motor to a slower speed for driving the spindle screw 159. The motor 163 turns the planetary gear 161, which turns the spindle screw 159 at a slower rotation speed than the speed of the motor. Turning the spindle screw 159 runs the spindle nut back and forth along the inner tube axis. The inner tube 165 extends and retracts, while the outer tube 155 is a cover for the spring 153 to keep out dust and water. A circuit element 169 is associated with the motor 163. A separate engine control unit (ECU) controls the motor in conjunction with the circuit element 169. Another joint 171 connects the other end of the power back door drive device 150 to the back door. Joint 151 is similar to the joint 171.
An end of the spindle screw 159 includes a stopper 167. The spindle nut 157 is attached to one end of the inner tube 165. The stopper 167 is a fixed device on the end of the spindle screw 159 that acts to stop the spindle nut 157 to jam against and stop the spindle screw 159 at the end of the travel of the spindle nut 157.
Operation of the power back door is by rotation of the motor 163 as controlled by the ECU and rotation of the planetary gear 161. The spindle screw 159 is rotated, and the power drive device is expanded along the tube axial direction by movement of the spindle nut 157 as it screws onto the spindle screw 159. Contraction of the unit is performed by reverse rotation of the spindle screw 159, rotation of the planetary gear 161, and rotation of the back door motor 163. The spindle nut 157 is stopped by the stopper 167 when the inner tube 165 is fully extended and the spindle screw 159 reaches the end of travel.
An aspect of the present disclosure includes a pair of power back door drive devices 150, in which the length of travel of one of the power back door drive devices is shorter than the other. Regarding
Provided the pair of power back door drive devices 312, 314, in which the travel length of one of the drive device is shorter than the travel length of the other of the drive devices, the opening time of the back door is reduced without any additional complex mechanisms and the back door does not bounce. As such, a user experiences a more solid operation of the door without noticing a difference in operation between the two power back door drive devices. The user may sense that the back door has an improved quality due to the solid operation.
Numerous modifications and variations are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
Thus, the foregoing discussion discloses and describes merely exemplary embodiments of the present invention. As will be understood by those skilled in the art, the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the disclosure of the present invention is intended to be illustrative, but not limiting of the scope of the invention, as well as other claims. The disclosure, including any readily discernible variants of the teachings herein, defines, in part, the scope of the foregoing claim terminology such that no inventive subject matter is dedicated to the public.
