Integrated Park Module Latch for Low-Force Not-Park Holding
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Solution Overview
Problem
Current Integrated Park Modules (IPMs) for shift-by-wire systems in automatic transmissions require large, powerful, and expensive solenoids to hold the transmission in the Not-Park position, which is undesirable for cost and size considerations.
Innovation Solution
The IPM design incorporates a motor-driven gear-train system with a low-force electromagnet and dual pivoting link latch or bell crank latch systems to retain the slider in the Not-Park position, eliminating the need for a large solenoid by utilizing electromagnetic and mechanical advantages to reduce the required holding force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large, powerful solenoid is used to hold the transmission in the Not-Park position, then the transmission can be reliably retained in the Not-Park position, but the size and cost of the actuator system increases
Solution Approach 1:
The holding function is divided into two independent subsystems: a latch mechanism that provides mechanical retention and a low-force electromagnet that provides electrical control. This segmentation allows each component to be optimized for its specific function, eliminating the need for a single large solenoid and reducing overall actuator size and cost.
Solution Approach 2:
The latch mechanism acts as an intermediary between the high-force requirement for holding the transmission in Not-Park position and the low-force electromagnet. The latch provides mechanical advantage through its linkage geometry, allowing the small electromagnet force to be amplified into sufficient holding force, thereby reducing the size of the electromagnet needed.
2Reliability
If a large, powerful solenoid is used to hold the transmission in the Not-Park position, then the transmission can be reliably retained in the Not-Park position, but the cost of the actuator system increases
Solution Approach 1:
The holding function is divided into two independent subsystems: a latch mechanism that provides mechanical retention and a low-force electromagnet that provides electrical control. This segmentation allows each component to be optimized for its specific function, eliminating the need for a single large solenoid and reducing overall actuator size and cost.
Solution Approach 2:
The latch mechanism acts as an intermediary between the high-force requirement for holding the transmission in Not-Park position and the low-force electromagnet. The latch provides mechanical advantage through its linkage geometry, allowing the small electromagnet force to be amplified into sufficient holding force, thereby reducing the size of the electromagnet needed.
3Weight of stationary object
If a low-force electromagnet with latch mechanism is used instead of a large solenoid, then the size and cost of the actuator system is reduced, but the complexity of the mechanism increases
Solution Approach 1:
The latch mechanism and electromagnet are merged into a single integrated assembly where the electromagnet directly actuates the latch linkage. This integration reduces the number of separate components and simplifies the overall structure, offsetting the added complexity of the latch mechanism itself.
Solution Approach 2:
The latch mechanism is designed to automatically engage and disengage based on the position of the slider and the force applied by the electromagnet. The mechanical advantage built into the latch geometry allows it to self-lock in the Not-Park position without requiring continuous high-force input, reducing the burden on the electromagnet and simplifying control.
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 allows for a smaller, less expensive actuator system that can automatically shift the transmission to the Park position in case of power loss, reducing the overall size and cost while maintaining reliable operation.
Implementation Method 1
a low-force electromagnet and dual pivoting link latch or bell crank latch systems to retain the slider in the Not-Park position
Implementation Method 2
motor-driven gear-train system with a low-force electromagnet and dual pivoting link latch or bell crank latch systems
Data Source
AI summary
A shift-by-wire system comprises an integrated park module including a slider, a motor, a spring, and an actuator system. The slider can be disposed in a park position (PP) and a not-parked position (NPP) corresponding to a park mode and a not-park mode of a transmission, respectively. The motor and a gear-train cause the slider to move from the PP to the NPP and the spring urges the slider from the NPP to the PP. The actuator system retains the slider in the NPP after the motor and the gear-train have disengaged from the slider. The gear-train includes a default position (DP) corresponding to the PP and a maximum lift region (MLR) in which the actuator system retains the slider in the NPP. The gear-train rotates from the MLR to the DP while the actuator system retains the slider in the NPP.