Cam Profile Segmentation for Compact High-Stroke Actuation

Solution Overview

Problem

Conventional cam devices are difficult to miniaturize due to the complexity of the drive mechanism and the requirement for a larger diameter to accommodate a larger stroke and increased speed, which complicates the integration of multiple action units in a narrow space, leading to increased device size.

Innovation Solution

A cam device with a camshaft, cam roller, rotary drive device, and linear motion guide, featuring a cam surface with a single constant velocity curve and non-continuous section, allowing for controlled rotational motion to reproduce lift and pause steps, enabling miniaturization and varying operation profiles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the speed on the output side is increased or a larger stroke is required, then the allocation angle of the lift region is reduced or the lift stroke is increased, but a larger diameter is required due to the limitation of the pressure angle

Engineering Contradiction:

Improveoutput speedVSAvoidcam diameter

Core Design Contradiction:

SpeedVSLength of stationary object

Solution Approach 1:

The cam surface is divided into multiple independent lift regions (first lift region, second lift region, third lift region) with distinct allocation angles. This segmentation allows each region to be optimized independently, enabling the cam to achieve high output speeds without requiring a large diameter, as each segment can operate within acceptable pressure angle limits.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a programmable control system that dynamically adjusts the rotation speed of the camshaft based on the position of the cam roller. The control unit increases rotation speed when the cam roller is in dwell regions and decreases it during lift regions, allowing the cam to operate at high speeds overall while maintaining acceptable pressure angles during critical lifting operations.

Inventive Principle:

Principle #15Dynamics

2Productivity

If a larger diameter cam is used to accommodate larger stroke and increased speed, then the cam can provide required movement, but it is difficult to integrate the cam plate in the vicinity of the action units and the size of the entire cam device is increased

Engineering Contradiction:

Improveoutput capabilityVSAvoidcam device size

Core Design Contradiction:

ProductivityVSVolume of moving object

Solution Approach 1:

The cam surface is divided into multiple independent lift regions (first lift region, second lift region, third lift region) with distinct allocation angles. This segmentation allows each region to be optimized independently, enabling the cam to achieve high output speeds without requiring a large diameter, as each segment can operate within acceptable pressure angle limits.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a programmable control system that dynamically adjusts the rotation speed of the camshaft based on the position of the cam roller. The control unit increases rotation speed when the cam roller is in dwell regions and decreases it during lift regions, allowing the cam to operate at high speeds overall while maintaining acceptable pressure angles during critical lifting operations.

Inventive Principle:

Principle #15Dynamics

3Area of stationary object

If multiple action units are integrated and arranged in a narrow range, then the device compactness is improved, but the cam plate integration becomes difficult and the overall device size increases

Engineering Contradiction:

Improvedevice footprintVSAvoidcam integration complexity

Core Design Contradiction:

Area of stationary objectVSDevice complexity

Solution Approach 1:

The cam is designed with multiple lift regions that can serve different action units simultaneously. The cam roller can contact different lift regions at different times, allowing a single cam to control multiple action units with different stroke requirements. This multi-functionality enables compact integration of multiple action units without requiring separate cam mechanisms for each.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention uses a programmable control system that dynamically adjusts the rotation speed of the camshaft based on the position of the cam roller. The control unit increases rotation speed when the cam roller is in dwell regions and decreases it during lift regions, allowing the cam to operate at high speeds overall while maintaining acceptable pressure angles during critical lifting operations.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11920667B2Cam device, part manufacturing device, bearing manufacturing device, part manufacturing method, machine manufacturing method, and cam device miniaturization method

Publication Date: 2024.03.05 NSK LTD

AI summary

A cam device includes a cam, a cam roller, a rotary drive device, a linear motion guide device, and an action unit. A cam profile of the cam includes a rotary end at a circumferential one end, at which a camshaft is non-rotatable in a reverse direction by the cam roller, a cam surface from the rotary end to the circumferential other end, on which the cam roller is abuttable, and formed of a single CV curve from a vicinity of the rotary end to the circumferential other end of the cam surface, and a non-continuous section formed between the rotary end and the circumferential other end of the cam surface and not in contact with the cam roller.