Rack-and-Sector Motion Converter for Stable Reciprocating Rotation

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Solution Overview

Problem

Existing reciprocating linear/rotational motion conversion devices, such as crank link mechanisms and sector-gear engines, suffer from low transmission efficiency, high energy consumption, and unstable operation due to mechanical friction and misalignment issues.

Innovation Solution

A reciprocating linear/rotational motion conversion device with a reversing mechanism that synchronously rotates with the main shaft and reversing block, ensuring accurate engagement and disengagement of the sector gear with the gear rack pair, reducing mechanical friction and allowing smooth, continuous operation by constraining the rack frame along a predetermined trail.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a crank link mechanism is used for motion conversion, then the structure is simple and easy to manufacture, but the transmission efficiency is low and energy consumption is high

Engineering Contradiction:
Improvestructural simplicityVSAvoidtransmission efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The motion conversion is divided into two independent stages: first the piston converts reciprocating motion to rotational motion of the main shaft, then the rack and pinion mechanism converts rotational motion to reciprocating motion of the crosshead. This segmentation allows each stage to be optimized independently, improving overall transmission efficiency while maintaining manufacturing simplicity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The main shaft acts as an intermediary element between the piston and the rack mechanism. It receives rotational motion from the piston and transmits it to the rack, enabling efficient motion conversion while reducing mechanical friction and energy loss compared to direct crank link mechanisms

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of energy

If a sector-gear mechanism is used for motion conversion, then the transmission efficiency is improved, but the operation stability deteriorates due to inaccurate reengagement

Engineering Contradiction:
Improvetransmission efficiencyVSAvoidoperation stability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The rack frame serves as a feedback element that guides the reversing block along a predetermined trail. This ensures that the sector gear and gear rack maintain accurate relative positions during disengagement and reengagement, preventing misalignment and ensuring stable operation while maintaining high transmission efficiency

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The reversing mechanism performs preliminary actions by synchronously rotating with the main shaft to prepare the sector gear and gear rack for accurate reengagement before the actual motion conversion begins. This preliminary positioning ensures smooth and stable operation without impact or misalignment

Inventive Principle:
Principle #10Preliminary action

3Productivity

If a shaft type connecting rod transmission system is used, then the motion conversion capability is achieved, but the mechanical friction increases and the system vibrates

Engineering Contradiction:
Improvemotion conversion capabilityVSAvoidmechanical friction and vibration
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The invention replaces the traditional shaft type connecting rod mechanical system with a rack and pinion mechanism driven by a main shaft. This substitution eliminates the sliding friction between connecting rod surfaces and reduces vibration by using rolling contact in the gear mechanism, while maintaining full motion conversion capability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 significantly improves transmission efficiency, reduces energy consumption, and ensures stable, continuous operation by minimizing mechanical friction and impact, enabling accurate reengagement of the sector gear with the gear rack pair.

Implementation Method 1

a linear motion guiding mechanism 2, a sector gear 3 and a rack frame 4 linearly moving along the linear motion guiding mechanism 2

Methodology Applied
Scientific EffectGravitation: Gravitation

Implementation Method 2

A gear rack pair is arranged on the inner wall of the rack frame 4. The gear rack pair comprises a first gear rack 41 and a second gear rack 42 separately arranged on both sides of the sector gear 3

Methodology Applied
Scientific EffectGear mechanism: Gear

Implementation Method 3

enables accurate constraint on the rack frame by the reversing mechanism in the transitional phase and reversing phase

Methodology Applied
Scientific EffectMechanical constraint: Mechanical Force

Implementation Method 4

the reciprocation of the slide block in operation increases load and mechanical friction of the system

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3627001B1Reciprocating linear motion and rotation motion transforming device, and cylinder device
Publication Date: 2023.09.13 ZHENG ANQING
  • EP3627001B1 patent drawingFigure 1
  • EP3627001B1 patent drawingFigure 2
  • EP3627001B1 patent drawingFigure 3

AI summary

The invention discloses a reciprocating linear/rotational motion conversion device and a cylinder device, in particular to a reciprocating linear/rotational motion conversion device and a cylinder device used in the mechanical transmission field. The reciprocating linear/rotational motion conversion device comprises a main shaft, a linear motion guiding mechanism, a sector gear and a rack frame. The sector gear is fixedly connected with the main shaft. A rack pair is arranged on the inner wall of the rack frame. The rack pair comprises a first gear rack and a second gear rack separately arranged on both sides of the sector gear. The reciprocating linear/rotational motion conversion device further comprises a reversing mechanism fixedly connected with the main shaft. The cylinder device comprises the reciprocating linear/rotational motion conversion device, connecting rods, pistons and cylinder bodies. The cylinder body is sleeved on the piston, and a cylinder head is arranged on one end of the cylinder body. With the solution of the invention, the transmission efficiency can be significantly improved to reduce energy consumption and achieve smooth and continuous operation.