Slip-controllable Brake Pressure Generator with Back-pressure Isolation
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Solution Overview
Problem
Existing vehicle brake systems face challenges in achieving compact and lightweight designs for pressure generators while maintaining the ability to rapidly build up brake pressure, particularly during ABS braking and pedestrian protection scenarios, which requires a powerful and heavy drive to overcome back pressure from the master brake cylinder.
Innovation Solution
Incorporating check valves and pulsation damping devices in the pressure generator to prevent back pressure from the master brake cylinder from affecting startup and to dampen pressure pulsations, allowing for a compact and lightweight drive with reduced startup current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the pressure generator drive is designed to be powerful enough to overcome back pressure from the master brake cylinder, then the brake pressure can be regulated effectively, but the drive becomes larger and heavier
Solution Approach 1:
The check valve is pre-installed in the pressure line between the pressure generator and the master brake cylinder to prevent back pressure from reaching the pressure generator during startup. This preliminary protective action allows the pressure generator to start up without fighting against the full back pressure of the master brake cylinder, enabling the use of a smaller, lighter drive motor while still maintaining effective brake pressure regulation capability.
2Productivity
If the pressure generator drive is designed to be more powerful for rapid brake pressure build-up, then the productivity increases, but the device complexity and weight increase
Solution Approach 1:
The check valve acts as an intermediary element that selectively allows pressure medium to flow from the master brake cylinder to the pressure generator during normal operation while blocking the reverse flow of high back pressure during startup. This intermediary protection mechanism enables the pressure generator to operate with a less powerful, simpler drive while still achieving the required rapid brake pressure build-up rate through controlled pressure medium flow.
3Ease of manufacture
If the drive is designed for compact dimensions and low weight, then the ease of manufacture improves, but the power to overcome back pressure is insufficient
Solution Approach 1:
The harmful back pressure effect is extracted and isolated from the pressure generator startup process by introducing a check valve in the pressure line. This extraction of the adverse back pressure influence allows the pressure generator to be manufactured with a compact, lightweight drive that would be insufficient if it had to directly overcome the full back pressure of the master brake cylinder, thereby improving ease of manufacture while maintaining adequate power for brake pressure regulation.
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
Enables a compact, lightweight, and cost-effective pressure generator that can quickly deliver a large volume of pressure medium with lower startup and operational currents, meeting the demands of rapid brake pressure build-up without increasing size or weight.
Implementation Method 1
springless, pressure-actuated check valves are preferably used, which have a valve seat and a valve-closing body that controls this valve seat
Implementation Method 2
Pulsation damping devices comprise a damping chamber with a variable volume (so-called C element) and a downstream throttle element (so-called R element)
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a slip-controllable vehicle brake system having a drivable pressure generator (26) for supplying at least one wheel brake (14) of a brake circuit with pressure medium. The pressure generator (26) is equipped with at least one pump inlet valve (30) and at least one pump outlet valve (32), to control the throughput of the pressure medium. Novel system functions, such as pedestrian protection, require that high pressure medium volumes be provided to the wheel brakes (14) increasingly faster. A corresponding design of the pressure generator (26) requires a drive having correspondingly increased power. For example, in the case of ABS braking, a high braking pressure generated by the driver works against the starting of the pressure generator (26) and increased starting currents occur on the drive. The modified design disadvantageously increases the weight and outside dimensions of the drive. In order to ease the starting of the drive and to limit the required starting current, according to the invention, means (40) are provided downstream of the pump outlet valve (32) which prevent an exerting of the pressure generator (26) on the pressure side (38) with the pressure of the main brake cylinder (10), at least at the start of pump conveying. More compact, lighter, and more cost-effective drives can be used for the pressure generator (26) as a result.