Hydraulic Actuation Device for Friction Clutch with Reversible Pump
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Solution Overview
Problem
Existing hydraulic actuating devices for motor vehicles require high energy to charge pressure accumulators to levels above the maximum needed, leading to inefficiency and frequent recharging, and suffer from leakage issues with slide valves, increasing costs and reducing efficiency.
Innovation Solution
A hydraulic actuating device with a clutch control cylinder and a locking device that allows reversible pumping to actuate the clutch piston only when necessary, eliminating the need for pressure accumulators and slide valves, and using an electromagnetic actuator for controlled movement, reducing energy consumption and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure accumulator is charged to a pressure level far above the maximum required, then the required working pressure can be provided after the required amount is removed, but energy consumption increases and device efficiency decreases
Solution Approach 1:
The system dynamically adjusts the pump operation based on actual demand. The pump is controlled to generate hydraulic pressure only when the clutch needs to be actuated, rather than continuously charging the accumulator to high pressure. The reversible pump switches pumping direction based on whether clutch engagement or disengagement is required, optimizing energy usage according to the specific operational need.
Solution Approach 2:
The system changes the pressure parameter dynamically rather than maintaining a constantly high pressure level. The pump generates pressure only when needed and releases it after actuation, transforming the pressure profile from static high-pressure storage to dynamic on-demand pressure generation, thereby reducing energy consumption while maintaining reliability.
2Device complexity
If slide valves are used for hydraulic control, then the system can function with simple structure, but leakage occurs and pressure accumulator discharges completely over service life
Solution Approach 1:
The invention extracts and removes the slide valve component from the system entirely. By eliminating the slide valve, the source of leakage is removed, and the pressure retention problem is solved. The system achieves hydraulic control through alternative means that do not rely on sliding密封 surfaces, thereby maintaining reliability without sacrificing structural simplicity.
Solution Approach 2:
The system uses a disposable-like approach to pressure control, where pressure is generated on-demand and consumed immediately for actuation, rather than attempting to retain pressure indefinitely in an accumulator. This eliminates the need for high-reliability pressure retention components and accepts periodic recharging as a normal operational cycle.
3Reliability
If the pump is operated frequently to recharge the pressure accumulator, then working pressure is maintained, but energy consumption increases and efficiency decreases
Solution Approach 1:
The system employs periodic pump operation synchronized with actual clutch actuation requirements. Instead of continuous or frequent periodic charging, the pump operates only when a clutch engagement or disengagement is needed. This transforms the charging cycle from a time-based periodic operation to an event-based periodic operation, reducing energy waste while maintaining pressure reliability.
Solution Approach 2:
The system serves itself by generating hydraulic pressure exactly when and where it is needed for clutch actuation. The reversible pump provides pressure directly to the clutch actuator on-demand, eliminating the intermediary accumulator that requires frequent recharging. This self-service approach to pressure generation minimizes energy loss by avoiding the inefficiencies of repeated charging cycles.
4Reliability
If a locking device with electromagnetic actuator is used for the clutch piston, then security against incorrect operation is enhanced, but device complexity increases
Solution Approach 1:
The locking device is merged with the clutch actuator system as an integrated unit. The electromagnetic actuator and locking mechanism are combined with the existing hydraulic actuation components, creating a unified control system. This integration adds the safety function without requiring completely separate control systems, thereby limiting the increase in overall device complexity while achieving enhanced reliability.
Solution Approach 2:
The electromagnetic actuator serves as an intermediary between the control signal and the clutch actuation. It mediates the actuation process by controlling the release of the locking device, ensuring that clutch engagement or disengagement occurs only when properly commanded. This intermediary function adds safety without requiring complex mechanical linkages, using electrical control to simplify the overall structure while enhancing reliability.
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 significantly improves overall efficiency and reduces costs by minimizing energy usage and eliminating the need for pressure accumulators and slide valves, while enhancing security against incorrect operation.
Implementation Method 1
a pump which can be driven via an electric pump drive in order to move hydraulic fluid in a pumping direction
Implementation Method 2
which, by means of an actuator that can be controlled electrically via the control unit, moves from the blocking position against the spring preload into a release position
Data Source
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AI summary
The device has a power unit (12) for producing hydraulic pressure by using a pump (P) that is driven by an electrical pump drive (M). A locking device (26) is attached to a piston (20) of a clutch adjusting cylinder (CC), and has a locking element (28) that is movable from a locking position to a releasing position by an actuator (32) controlled by a control device (ECU). Pump direction of the pump is reversible for hydraulically loading the piston. The control device coordinates electrical controlling of the pump drive and the actuator for engaging and disengaging a friction clutch (C).