Shift Device Cam Member Voltage Control for Noise Reduction
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Solution Overview
Problem
In by-wire shift devices, returning the knob to the parking position without shifting the operation position can result in annoying driving noise due to the automatic return control of the gear mode, causing the knob operation position to differ from the transmission gear mode.
Innovation Solution
A shift device with a knob, cam member, and controller that reduces the voltage applied to the drive source during the pre-engagement section, gradually increases voltage in the pre-post engagement section, and determines engagement based on time or current value, minimizing noise by controlling the rotation speed and engagement of the cam member and detent pins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the controller performs automatic return control to shift the gear mode to parking position, then the transmission gear mode is correctly positioned, but the knob rotation generates driving noise that annoys the driver
Solution Approach 1:
The patent applies dynamics by making the rotation speed of the cam member variable during the automatic return control. The rotation speed is controlled to be lower in the pre-engagement section (before the cam member engages the knob) and higher in the post-engagement section (after engagement). This dynamic speed adjustment reduces the striking noise when the cam member engages the knob while still achieving reliable gear mode positioning.
Solution Approach 2:
The patent changes the rotational speed parameter of the cam member during the engagement process. Specifically, the rotation speed is set to a first (lower) speed in the pre-engagement section and a second (higher) speed in the post-engagement section. This parameter change effectively reduces the noise generated during engagement while maintaining the reliability of the gear mode positioning function.
2Productivity
If the cam member rotates at high speed to quickly return the knob to parking position, then the operation is efficient, but the engagement generates striking noise
Solution Approach 1:
The patent applies dynamics by making the rotation speed of the cam member variable during the automatic return control. The rotation speed is controlled to be lower in the pre-engagement section (before the cam member engages the knob) and higher in the post-engagement section (after engagement). This dynamic speed adjustment reduces the striking noise when the cam member engages the knob while still achieving reliable gear mode positioning.
Solution Approach 2:
The patent changes the rotational speed parameter of the cam member during the engagement process. Specifically, the rotation speed is set to a first (lower) speed in the pre-engagement section and a second (higher) speed in the post-engagement section. This parameter change effectively reduces the noise generated during engagement while maintaining the reliability of the gear mode positioning function.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces the striking noise when returning the knob to a predetermined position, such as the parking position, by decreasing the rotation speed and increasing the voltage gradually, thereby minimizing annoyance to the driver.
Implementation Method 1
The cam member engages a portion of the knob in a rotation direction of the knob. The cam member rotates integrally with the knob only when engaged with the portion of the knob.
Implementation Method 2
The drive source rotates the cam member. The controller controls the drive source to rotate the knob to an operation position corresponding to a predetermined gear mode.
Data Source
AI summary
A shift device includes a knob that is rotatable to select one of a plurality of gear modes of a transmission of a vehicle and a cam member that engages a portion of the knob in a rotation direction of the knob. The cam member rotates integrally with the knob only when engaged with the portion of the knob. The shift device further includes a drive source that rotates the cam member and a controller. The controller controls the drive source to rotate the knob to an operation position corresponding to a predetermined gear mode if a particular condition is satisfied. The controller decreases a voltage applied to the drive source when the cam member is rotated in at least a pre-engagement section until the cam member engages the portion of the knob from the voltage applied when the cam member is rotated in other sections.