Electric Vacuum Pump Transmission with Anti-Rotation Eccentric Shafts

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Solution Overview

Problem

Current electric vacuum pumps with eccentric wheel mechanisms have complex structures, produce noise, and face challenges in effectively transmitting torque between the motor shaft and multiple pistons.

Innovation Solution

A transmission system using a stud, eccentric shafts, and connecting rods to connect the motor shaft to pistons, featuring an anti-rotation structure between adjacent eccentric shafts to ensure smooth and efficient torque transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If an eccentric wheel mechanism is used to connect the motor shaft to the piston, then the structure can transmit motion, but the structure becomes complicated and produces loud noise

Engineering Contradiction:
Improvestructure complexityVSAvoidnoise
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent divides the transmission system into separate functional components: a motor shaft, multiple eccentric shafts (with each eccentric shaft having its own eccentric portion), and connecting rods. This segmentation allows each component to perform its specific function independently, simplifying the overall structure compared to a complex eccentric wheel mechanism while reducing noise through better distribution of mechanical stresses.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces connecting rods as intermediary elements between the eccentric shafts and pistons. These connecting rods smoothly transmit the reciprocating motion from the eccentric shafts to the pistons, eliminating the need for complex direct coupling mechanisms and reducing noise generation at the transmission interface.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If multiple pistons are used in the electric vacuum pump, then the pumping capacity increases, but effective torque transmission between the motor shaft and each piston becomes difficult

Engineering Contradiction:
Improvepumping capacityVSAvoidtorque transmission efficiency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent employs multiple independent eccentric shafts (at least two, preferably three) that can be independently connected to the motor shaft and to individual pistons via connecting rods. This segmentation allows each piston-eccentric shaft pair to function semi-independently, ensuring reliable torque transmission to each piston while maintaining high pumping capacity through the combined output of all pistons.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The motor shaft is designed with universal coupling capabilities to connect to multiple eccentric shafts simultaneously. The standardized interface between the motor shaft, eccentric shafts, and connecting rods allows the same basic mechanism to serve multiple pistons, ensuring consistent and reliable torque transmission across all pistons while maintaining high productivity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If adjacent eccentric shafts are connected without anti-rotation structures, then the assembly is simpler, but torque transmission becomes unstable and positioning is inaccurate

Engineering Contradiction:
Improveassembly complexityVSAvoidtorque transmission stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces asymmetric anti-rotation structures (such as keys, splines, or asymmetric coupling features) at the interfaces between adjacent eccentric shafts. These asymmetric features prevent relative rotation between connected eccentric shafts while maintaining simple assembly procedures, ensuring stable torque transmission and accurate positioning without significantly increasing assembly complexity.

Inventive Principle:
Principle #4Asymmetry

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 simplifies the structure, reduces noise, and improves torque transmission efficiency between the motor shaft and pistons, enabling smooth operation and accurate positioning of the eccentric shafts.

Implementation Method 1

torque is smoothly and safely transmitted through friction between the end surfaces of eccentric shafts

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4542034A1Transmission system for electric vacuum pump
Publication Date: 2025.04.23 ZF COMMERCIAL VEHICLE SYSTEMS (QINGDAO) CO LTD
  • EP4542034A1 patent drawingFigure 1
  • EP4542034A1 patent drawingFigure 2
  • EP4542034A1 patent drawingFigure 3

AI summary

A transmission system for an electric vacuum pump used for transmission connection between a motor shaft (10) and a plurality of pistons (20) includes: a stud (30) coaxially connected to the motor shaft (10); a plurality of eccentric shafts (40) threadedly connected outside the stud (30) in sequence, wherein end surfaces of adjacent eccentric shafts (40) abut against each other and are fitted with each other via an anti-rotation structure (44a, 44b); and a plurality of connecting rods (50), each having a proximal end (50a) connected to one of the eccentric shafts (40), and a distal end (50b) connected to one of the pistons (20).