Belt-Type CVT Cam Plate Segmentation for Manufacturing

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Solution Overview

Problem

The manufacturing of belt-type continuously variable transmissions is complicated due to the difficulty in processing deep-drawn cam plates, making it challenging to produce these transmissions efficiently.

Innovation Solution

A belt-type continuously variable transmission design that eliminates the need for deep drawing by using a cam plate with notched guide members and sliders that engage with guide ribs, allowing for easier manufacturing and assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If deep-drawn cam plates are used to guide the movable sheave member, then the transmission can achieve proper belt groove control, but the manufacturing process becomes complicated and costly

Engineering Contradiction:
Improvebelt groove controlVSAvoidmanufacturing process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The cam plate is divided into a plate main body and separate guide members that are notched into it. This segmentation allows the guide members to be manufactured independently using simpler processes, then attached to the plate main body, avoiding the need for complex deep-drawing of integrated guide structures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The notched guide members act as intermediaries between the cam plate and the movable sheave member. These notched structures provide the necessary guiding function while being manufacturable through less complex processes than deep-drawn integrated guides, thus mediating between functional requirements and manufacturing ease.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If deep-drawn cam plates with guide grooves are used, then proper guidance of the movable sheave member is achieved, but production costs increase

Engineering Contradiction:
Improveguidance functionVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The guide function is segmented from the cam plate body into separate notched guide members. This allows each component to be manufactured using optimal, simpler processes for its specific function, reducing overall production cost while maintaining the necessary guidance reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The notched guide members can be manufactured as simpler, more cost-effective components compared to deep-drawn integrated guides. While individual guide members may be simpler structures, the overall system achieves reliable guidance at lower production cost through this component approach.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Strength

If complex deep-drawing processes are used for cam plates, then proper structural integrity is achieved, but manufacturing time and complexity increase

Engineering Contradiction:
Improvestructural integrityVSAvoidmanufacturing efficiency
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

By segmenting the cam plate into a plate main body and separate notched guide members, each component can be manufactured using more efficient processes. The plate main body maintains structural integrity, while the guide members provide functional guidance without requiring complex deep-drawing, thus improving overall manufacturing efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The guide members are prepared with notches in advance as separate components, then attached to the plate main body. This preliminary preparation of components separately allows for more efficient manufacturing of each part using optimized processes for its specific requirements, improving overall production efficiency.

Inventive Principle:
Principle #10Preliminary action

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 design simplifies the manufacturing process, reduces production costs, and enhances the durability of the transmission components, enabling the production of belt-type continuously variable transmissions at a lower cost while maintaining performance.

Implementation Method 1

When the rotation speed of the primary sheave increases, centrifugal force acting on the roller weights increases accordingly. Thus, the roller weights shift toward the outside in the radial direction while pressing the primary movable sheave member toward the primary fixed sheave member.

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

As a result, the belt is pulled toward the primary sheave, and the belt winding diameter of the secondary sheave decreases.

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP1927791B1Bell-type continuously transmission and straddle-type vehicle including the same
Publication Date: 2012.08.08 YAMAHA MOTOR CO LTD
  • EP1927791B1 patent drawingFigure 1
  • EP1927791B1 patent drawingFigure 2
  • EP1927791B1 patent drawingFigure 3

AI summary

To provide a belt-type continuously variable transmission which is easily manufactured, the belt-type continuously variable transmission 14 includes a primary sheave 36, a secondary sheave 37, and a belt 41 wound around the primary sheave 36 and the secondary sheave 37. The primary sheave 36 includes a fixed sheave member 36a, a movable sheave member 36b, a cam plate 60, and a roller weight 44. The movable sheave member 36b has a guide rib 55 extending toward the cam plate 60. The cam plate 60 has a slider 62 having a guide groove 63. The position of the radially outer portion of an end surface 62a of the slider 62 is shifted toward the right in the rotation axis extending direction from the position of the radially inner portion of the end surface 62a.