Automotive Vacuum Pump Radial Friction Bearing Design
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Solution Overview
Problem
Existing automotive vacuum pumps are not simple and cost-effective in generating vacuum pressures below 600 millibar for actuating pneumatic automotive devices.
Innovation Solution
A vane pump design with a rotatable pump rotor body and shiftable vane, featuring a radial friction bearing for sealing and support, a separate axial rotor retaining arrangement for maintaining axial position, and lubrication conduits to reduce friction and wear, along with spring stoppers for valve control, allowing efficient operation and cost-effective production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate axial rotor retaining arrangement is provided at the high-pressure end, then the rotor body is blocked from significantly moving axially, but the device complexity increases
Solution Approach 1:
The retaining sheet body combines multiple functions: it retains the rotor body axially, defines the spring stopper for the outlet valve, and provides structural support. By merging these functions into a single component, the patent reduces overall device complexity while maintaining reliable axial positioning of the rotor body.
Solution Approach 2:
The retaining sheet body serves as a multi-functional element that simultaneously acts as a rotor retaining arrangement, a valve stopper definition, and a structural support component. This multi-functionality approach eliminates the need for separate components, thereby reducing device complexity while ensuring reliable rotor body retention.
2Ease of operation
If the retaining sheet body defines a spring stopper for the outlet valve, then the valve opening position is limited, but the device complexity increases
Solution Approach 1:
The retaining sheet body integrates the spring stopper function directly into its structure, combining rotor retention and valve control features in a single component. This merging approach provides effective valve control while avoiding the complexity of separate valve stopping mechanisms.
3Reliability
If lubrication conduits are provided for the radial friction bearing, then friction and wearout are reduced, but the device complexity increases
Solution Approach 1:
The patent employs a lubrication conduit arrangement that delivers lubricant to the radial friction bearing through hydraulic principles. This system reduces friction and wearout of the bearing, improving reliability and durability, while the conduit integration minimizes the added complexity.
4Device complexity
If the radial friction bearing provides both radial support and sealing, then the device complexity is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The radial friction bearing is designed as a multi-functional component that simultaneously provides radial support for the rotor body and pneumatic sealing between the pump cavity and atmospheric pressure. This universal approach reduces device complexity by eliminating separate sealing mechanisms, while the sealing effectiveness is achieved through precise radial contact geometry.
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 design achieves efficient vacuum generation with reduced friction and wear, ensuring reliable operation and cost-effectiveness for automotive vacuum applications.
Implementation Method 1
The vacuum pump is provided with a radial friction bearing which is axially arranged between the vane slit and the high-pressure end of the pump rotor body
Implementation Method 2
The friction surfaces of the pump rotor are lubricated. Preferably, a lubrication conduit arrangement is provided for lubricating the radial friction bearing with a lubrication liquid
Implementation Method 3
when the vacuum pump is operating, the pump rotor body is axially pushed in the direction of the closed housing wall by the pressure difference between the pressures at the high-pressure end and the low-pressure end
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The application refers to an automotive vacuum pump (10) for pumping a gas, comprising a pump housing (12) defining a pump cavity (11), a pump rotor body (16) with at least one vane slit (18) supporting a shiftable vane (20) defining at least two rotating pumping chambers, the pump rotor body (16) having an axial low-pressure end (15) and a axial high-pressure end (17), the low-pressure end (15) being axially supported by a closed housing wall (13), so that the gas pressure inside the rotating pumping chamber is present at the low-pressure end (15) of the pump rotor body (16), the pump housing (12) being fluidically open at the high-pressure end (17), so that atmospheric pressure is present at the high-pressure end (17) of the pump rotor body (16), a separate axial rotor retaining arrangement (50) defined by a separate retaining sheet body (53) arranged in a transversal plane and axially blocking at least partially the high-pressure end (17) of the pump rotor body (16), and a radial friction bearing (80) axially arranged between the at least on vane slit (18) and the high-pressure end (17) of the pump rotor body (16).