Pantograph Exhaust Valve Control for Impact-Free Lowering
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Solution Overview
Problem
Current collectors for electrically or hybrid-electrically driven road vehicles face challenges in quickly and safely lowering rocker arrangements to storage positions without causing damage due to excessive impact, often requiring shock absorbers to mitigate the impact.
Innovation Solution
A current collector with a control mechanism that opens the exhaust air valve at an intermediate position to release excess pressure, preventing upward movement and ensuring a shorter, gentler storage lowering phase, thereby minimizing impact and potential damage without the need for shock absorbers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the exhaust air valve is kept closed during the lowering phase, then the rocker assemblies can be lowered rapidly using gravity, but the air pressure builds up to a maximum value that causes the rocker assemblies to rise again, requiring shock absorbers to dampen the impact
Solution Approach 1:
The exhaust air valve is designed to dynamically change its state from closed to open based on the rocker assembly position. The control means detect when the rocker assemblies reach the intermediate position and automatically open the valve, allowing the system to adapt its behavior during the lowering process to prevent both excessive speed and impact damage
Solution Approach 2:
The control means continuously monitor the position of the rocker assemblies and the air pressure in the air reservoir, using this feedback information to determine the optimal moment to open the exhaust air valve. This feedback mechanism ensures the valve opens precisely when needed to prevent upward movement and control the lowering phase
2Object-affected harmful factors
If the exhaust air valve is opened early to release pressure, then impact damage is reduced, but the lowering phase duration increases and the rocker assemblies cannot be lowered rapidly
Solution Approach 1:
The exhaust air valve is opened at the precise intermediate position during the lowering phase, after the rocker assemblies have already descended rapidly from the contact position. This timing allows the initial rapid lowering to occur without restriction, while the valve opening prevents excessive pressure buildup that would cause upward movement and extend the overall lowering time
3Device complexity
If a fixed flow cross-section throttle valve is used, then the design is simple, but the lowering phase duration cannot be optimized and shock absorbers are required
Solution Approach 1:
The exhaust air valve transitions from a static fixed flow cross-section design to a dynamic design where the flow cross-section can be changed by opening or closing the valve. This dynamic capability allows optimization of the lowering phase duration and elimination of shock absorbers without significantly increasing overall system complexity
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 enables rapid and safe lowering of rocker arrangements, reducing the risk of damage and eliminating the need for shock absorbers, while maintaining a balance between fall dynamics and storage phase movement, ensuring reliable and robust operation.
Implementation Method 1
a pneumatic lifting drive coupled to the support frame in such a way that, when the lifting drive is pressurized, the rocker arms can be raised from a lower position to an upper contact position
Implementation Method 2
when the pressure is released, lowered back into the lower position by their own weight
Implementation Method 3
The air reservoir can be connected to the environment via an exhaust duct with an exhaust valve... exhaust air flows from the lifting mechanism into the air reservoir due to the rocker arms' own weight until pressure equilibrium is reached
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a pantograph (2) for an electrically or hybrid-electrically powered road vehicle (1) for supplying electrical traction energy from a two-pole overhead contact line system, each contact pole having a contact wire (3). An articulated support rod (4) carries rocker assemblies (7) with contact strips (8) on the contact wire side and has a base joint (9) on the vehicle side for support on the road vehicle (1). A pneumatic lifting drive (12) is coupled to the support rod (4) such that the rocker assemblies (7) can be raised from a lower storage position (hA) to an upper contact position (hK) when the lifting drive (12) is pressurized, and lowered back to the storage position (hA) by their own weight when the pressure is released. The lifting drive (12) can be pneumatically connected to a compressed air supply (13) for pressurization and to an air reservoir (17) for pressure relief.The air reservoir (17) can be connected to the environment via an exhaust air duct (16, 16a, 16b) having an exhaust air valve (20). The exhaust air valve (20) can be switched via control means (21) to control a self-weight-driven lowering phase of the rocker assemblies (7), the control means (21) being designed to open the exhaust air valve (20) when the rocker assemblies (7) reach an intermediate position (hZ) in which the rising air pressure in the air reservoir (17) reaches a local maximum value. This provides a current collector (2) that enables rapid and reliable lowering of the rocker assemblies (7) with a simple design.