Power Transmission Clutch Cam Mechanism Drag Torque
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power transmission apparatuses with clutch devices face challenges in achieving high responsiveness and transmission capacity while minimizing drag torque and production costs, as they require high precision machining and often compromise on frictional engagement force due to conflicting relationships between frictional engagement force and responsiveness.
Innovation Solution
The power transmission apparatus incorporates an input side cam mechanism with small cam angles and an output side cam mechanism with large cam angles, allowing for reduced drag torque and increased frictional engagement force without the need for high precision machining, enabling high responsiveness and transmission capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the cam angle is reduced to increase frictional engagement force, then the frictional engagement force is improved, but the responsiveness is lowered
Solution Approach 1:
The clutch device is divided into multiple friction engagement elements (multiple friction plates and pressure plates) arranged in series. This segmentation allows the total frictional engagement force to be distributed across multiple interfaces, enabling the use of smaller cam angles while maintaining sufficient total engagement force. The multiple elements work together to achieve both high force and fast response.
Solution Approach 2:
Different cam angles are used for different cam mechanisms within the same clutch device. Specifically, odd-numbered cam mechanisms use a first cam angle while even-numbered cam mechanisms use a second cam angle. This local differentiation allows optimization of each cam mechanism's contribution to either force or responsiveness based on its position in the sequence.
2Loss of energy
If gaps between friction engagement elements are enlarged to reduce drag torque, then drag torque is reduced, but the clutch pack size is increased
Solution Approach 1:
The cam mechanisms are designed with movable cam plates that can dynamically adjust the gaps between friction engagement elements during operation. In the released state, gaps are enlarged to minimize drag torque. During engagement, the cam mechanisms press the friction plates together, dynamically reducing the gaps to ensure effective power transmission. This dynamic adjustment allows the clutch pack to maintain compact size while minimizing drag when disengaged.
3Force
If multiple cam mechanisms with different cam angles are used to resolve the force-responsiveness contradiction, then both frictional engagement force and responsiveness are improved, but manufacturing complexity and precision requirements are increased
Solution Approach 1:
The invention uses two discrete cam angle parameters (first cam angle and second cam angle) that are both within the range of 5 to 20 degrees. By limiting the cam angles to this specific range and using only two distinct values, the manufacturing precision requirements are kept manageable while still achieving the desired balance between frictional engagement force and responsiveness. The alternating pattern of these two parameters simplifies the design and manufacturing process compared to using continuously varying cam angles.
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 effectively reduces drag torque, enhances frictional engagement force, and improves responsiveness of the clutch device, achieving high transmission capacity without the cost and precision issues associated with traditional cam mechanisms.
Implementation Method 1
The spherical member 103 is sandwiched between a cam surface 101a formed on the drive side cam plate 101 and a cam surface 102a formed on the driven side cam plate 102 to be capable of being rolled between the cam surface 101a and the cam surface 102a
Implementation Method 2
a cam mechanism that can increase an output torque of an actuator to enhance a frictional engagement force of the clutch device
Implementation Method 3
an engagement element pack constituted by a plurality of input side friction engagement elements and a plurality of output side friction engagement elements
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Disclosed is a power transmission apparatus which can require no high precision machining and can reduce a drag torque, and is provided with a clutch device having a high responsiveness and a large engagement force. The power transmission apparatus comprises an input shaft 21, an output shaft 22, a clutch device 23, and an actuator 24. The clutch device 23 comprises a clutch hub 31, a clutch housing 32, a clutch pack 33 constituted by a plurality of inner clutch plates 61 and a plurality of outer clutch plates 62, an input side cam mechanism 34 for pressing the clutch pack 33 toward the output shaft 22, an output side cam mechanism 35 for pressing the clutch pack 33 toward the input shaft 21, a return spring 36 for urging the clutch pack 33 to have its elements moved away from each other, and a drive shaft 37 having an input side gear 37n for transmitting the driving force of the actuator 24 to the input side cam mechanism 34, and an output side gear 37d for transmitting the driving force of the actuator 24 to the output side cam mechanism 35.