Hydraulic Piston Pump Flow Control for Low-Temperature Noise
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Solution Overview
Problem
Hydraulic piston pumps in vehicle brake systems face increased pressure and load due to changing kinematic viscosity of brake fluid at low temperatures and dirt particles, leading to noise and operational issues.
Innovation Solution
The design incorporates additional outflow channels with varying cross-sections and configurations that allow the valve closing body to assume a defined preferred position, reducing pressure and noise by controlling flow based on pressure levels and preventing blockages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a single outflow channel with taper is used to create hydraulic low-pass filter effect, then noise is reduced, but pressure increases significantly at low temperatures due to viscosity changes
Solution Approach 1:
The single outflow channel is segmented into multiple outflow channels (first outflow channel and second outflow channel) with different geometries. The first outflow channel has a larger cross-section for low-temperature operation, while the second outflow channel has a smaller cross-section with taper for noise reduction at normal temperatures. This segmentation allows the system to handle viscosity changes without excessive pressure buildup while maintaining noise reduction capabilities.
Solution Approach 2:
The system dynamically adapts its flow characteristics through temperature-dependent viscosity changes. At low temperatures, the higher viscosity naturally restricts flow through both channels, preventing excessive pressure buildup. At normal temperatures, the valve closing body positioning creates a preferred flow path through the tapered second channel, maintaining the low-pass filter effect for noise reduction.
2Adaptability or versatility
If valve closing body moves freely between outflow channels in open position, then discharge control is flexible, but operating noise increases
Solution Approach 1:
Different local qualities are assigned to different outflow channels. The first outflow channel has a larger cross-section suitable for high-flow conditions, while the second outflow channel has a smaller cross-section with taper designed for noise reduction. The valve closing body is positioned to preferentially direct flow through the second channel during normal operation, creating local optimization for noise reduction while maintaining overall system flexibility.
Solution Approach 2:
The valve closing body acts as an intermediary that mediates between the two outflow channels. It can selectively direct flow through either channel based on operating conditions, serving as a controllable intermediary that balances the competing requirements of flow flexibility and noise reduction.
3Object-generated harmful factors
If outflow channel cross-section is reduced for throttling effect, then noise is reduced, but flow is impeded by dirt particles causing pressure increase
Solution Approach 1:
The system uses parameter changes in channel geometry to balance noise reduction and reliability. The second outflow channel has a smaller cross-section with taper for noise reduction, while the first outflow channel has a larger cross-section that is more resistant to blockage by dirt particles. This parameter variation allows the system to optimize for different operating conditions and maintain reliability even when one channel is partially blocked.
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 reduces the drive power required for piston pumps, optimizes component design, and minimizes noise and pressure increases, enhancing the overall performance and reliability of the hydraulic system.
Implementation Method 1
additional means which are flowed through together with a first outflow channel discharging pressure medium, the flow through the additional means being reduced compared to the flow through the first outflow channel as a function of the pressure in the first outflow channel
Data Source
Figure 1~2
Figure 3~5
Figure 4
AI summary
The invention relates to a hydraulic piston pump, particularly for a slip-controllable vehicle braking system. A piston pump according to the invention comprises hydraulically permanently permeable means (341; 342; 343; 344), the throughflow of which is carried out as a function of the pressure in an outflow channel (34) of the piston pump. A pressure medium flow only takes place if the pressure level in the outflow channel (34) has exceeded a threshold value. The latter takes place, for example, if the kinematic viscosity of the flowing pressure medium decreases due to low ambient temperatures, or if a throughflow of the outflow channel is (34) obstructed. By means of the proposed solution, excess pressure increases in the interior of the piston pump can be avoided, and the resulting loads for the pressurized pump components and the drive can be reduced. Otherwise, the operating behavior of the piston pump according to the invention corresponds to that of a known piston pump.