Automatic Gearbox Parking Lock with Dual Hydraulic Pump Circuits
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Solution Overview
Problem
Existing automatic gearboxes for motor vehicles lack a reliable and simple method for actuating the parking lock, which is crucial for preventing the vehicle from rolling away, especially on inclines, while also being cost-effective and space-efficient.
Innovation Solution
The automatic gearbox incorporates a reversible hydraulic pump with dual pump connections and hydraulic cylinders to hydraulically operate the parking lock, allowing for efficient adjustment between engaged and disengaged states, utilizing a spring-actuated mechanism for reliable operation and minimizing the need for additional hydraulic valves and pumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a hydraulic pump is used to supply hydraulic fluid to both the cooling device and the parking lock actuator, then the system can be integrated and space-efficient, but the reliability of parking lock actuation may be compromised due to shared hydraulic resources
Solution Approach 1:
The hydraulic pump is divided into two independent pump circuits: a first pump circuit dedicated to supplying the cooling device and a second pump circuit dedicated to supplying the parking lock actuator. This segmentation ensures that failures in one circuit do not affect the other, maintaining reliability while keeping the system compact through integrated pump housing.
Solution Approach 2:
A single hydraulic pump housing contains multiple pump units that perform different functions: one pump unit supplies the cooling device while another pump unit supplies the parking lock actuator. This multi-functionality achieves space efficiency without compromising reliability through circuit independence.
2Reliability
If additional hydraulic valves and pumps are added to improve parking lock actuation reliability, then the system becomes more robust, but the device complexity and cost increase
Solution Approach 1:
Multiple pump units are merged into a single integrated pump housing with independent circuits. This combining approach achieves the reliability of multiple systems while reducing overall complexity by eliminating the need for separate pump housings and reducing the number of external connections and control components.
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 provides a reliable, cost-effective, and space-efficient actuation of the parking lock, ensuring the vehicle remains secure against unintended movement, even if other systems fail, while maintaining a compact design.
Implementation Method 1
a hydraulic pump (14), in particular formed as an electric hydraulic pump, which is operable in a forward operation and in a reverse operation... conveys the hydraulic fluid... to the cooling device (12)... to the parking lock actuator (26)
Implementation Method 2
The hydraulic pump (14)... conveys the hydraulic fluid... to the cooling device (12) via a first pump connection (22)... and... to the parking lock actuator (26) via a second pump connection (24)
Data Source
AI summary
An automatic gearbox for a motor vehicle includes a lubricating or cooling device, a hydraulic pump having a first pump connection via which, in a forward operation of the hydraulic pump, the lubricating or cooling device can be supplied with a hydraulic fluid conveyed by the hydraulic pump during forward operation and thus flows through the first pump connection, and with a parking lock, which can be moved between an engaged state and a disengaged state and has a first operating space, into which the hydraulic fluid conveyed by the hydraulic pump during forward operation can be introduced so that the parking lock is hydraulically operable and an adjustment of the parking lock from one of the states into the other state can thereby be effected.