Hydraulic Clutch Latching Device for Pressure Loss
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Solution Overview
Problem
Hydraulically operated clutches in powertrain systems can unintentionally engage or disengage due to loss of hydraulic pressure, leading to potential damage to the powertrain system, as they return to their default position upon equipment or hydraulic system failure.
Innovation Solution
A clutch assembly with a latching device that includes a selectively retractable locking pin and a solenoid coil to lock the piston in a predetermined position, preventing unintended engagement or disengagement by overriding the spring biasing force, ensuring the clutch remains in a fixed state even without hydraulic pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hydraulically operated piston is used to actuate the clutch, then the clutch can be engaged or disengaged under normal operation, but the clutch may unintentionally engage or disengage upon loss of hydraulic pressure due to power or pump failure
Solution Approach 1:
The latching device is pre-configured with a locking pin that can engage with the piston at predetermined positions. Before hydraulic failure occurs, the system is designed so that the locking mechanism is ready to capture the piston in its current position, preventing any unintended movement when hydraulic pressure is lost.
Solution Approach 2:
The latching device acts as an intermediary mechanism between the hydraulic piston and the clutch members. It provides an additional layer of control by mechanically locking the piston in position, independent of the hydraulic system, thereby preventing unintended clutch engagement or disengagement.
2Reliability
If a latching device with locking pin is added to retain the piston position, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The latching device is integrated into the existing clutch assembly structure. The locking pin is incorporated within the piston or clutch member housing, and the spring mechanism is combined with the existing biasing springs in the clutch assembly, reducing the need for separate independent components.
Solution Approach 2:
The locking pin serves multiple functions: it can lock the piston in the engaged position, lock it in the disengaged position, and allow free movement when not engaged. The same mechanical structure serves both as a locking mechanism and as a position indicator, reducing the need for additional components.
3Reliability
If a spring biasing mechanism is used to return the piston to default position, then the clutch returns to safe position upon hydraulic failure, but the clutch may unintentionally engage due to spring force imbalance
Solution Approach 1:
The latching device is designed to counteract the spring biasing force before unintended engagement can occur. The locking pin engages with the piston at positions that prevent the spring from moving the piston unintentionally, while still allowing the spring to provide the necessary return force under normal operation.
Solution Approach 2:
The system incorporates mechanical feedback through the latching device that senses the piston position and the engagement state of the clutch. When the clutch is engaged, the locking pin is positioned to maintain that state; when disengaged, the locking pin allows the spring to return the piston to the disengaged position, providing continuous position verification.
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
The solution effectively prevents damage to the powertrain system by maintaining the clutch in a predetermined position during hydraulic pressure failures, ensuring safe operation and reducing the risk of mechanical damage.
Implementation Method 1
a solenoid coil disposed within the housing, a metallic plunger having an end defining the locking pin disposed within the solenoid coil
Implementation Method 2
a biasing member urging the metallic plunger in the extended position such that the locking pin protrudes from the latching device housing
Implementation Method 3
a piston selectively actuatable to move the second clutch member in the other of the first axial direction and the second axial direction, thereby overcoming a biasing force of the spring
Data Source
AI summary
A clutch assembly having a first clutch member, a second clutch member axially slidable in a first axial direction to engage the first clutch member and in a second axial direction to disengage from the first clutch member, a spring biasing the second clutch member in one of the axial directions, a piston actuatable to move the second clutch member in the other of the axial directions, thereby overcoming a biasing force of the spring, and a latching device to selectively lock the piston in at least one of the first axial direction and second axial direction. The latching device includes a selectively retractable locking pin. The piston has an external surface defining a slot to receive the locking pin, thereby locking the piston in the first position or the second position. A method of operating the clutch assembly is provided.