Hydrostatic Transmission Clutch for Differential Function
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Solution Overview
Problem
Conventional differentials for vehicles are bulky and lose torque if one wheel slips, making them unsuitable for integration with hydrostatic transmissions, and existing solutions with locking functions are expensive and even more bulky.
Innovation Solution
A hydraulic machine with a clutch system that alternates between coupling, freewheel, and slip configurations, using a cylinder block, pistons, and a multi-lobe cam to manage hydraulic pressure and switch between these configurations, allowing for adaptive torque transmission and speed differential management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional differentials are used to allow wheels to rotate at different speeds, then the vehicle can perform bends, but the differential structure becomes bulky
Solution Approach 1:
The patent merges the differential function with the hydrostatic transmission system by integrating a clutch mechanism into the existing hydraulic machine (pump or motor). The clutch is coupled to the rotating part of the hydraulic machine, allowing the differential functionality to be achieved within the existing transmission volume rather than adding a separate differential mechanism.
Solution Approach 2:
The clutch mechanism serves multiple functions: it enables differential operation during normal driving, provides torque transmission during acceleration, and allows wheel locking during slip conditions. This multi-functionality eliminates the need for separate differential and locking mechanisms, reducing overall system volume.
2Ease of operation
If standard differentials are used to allow speed differences between wheels, then the vehicle can turn, but the differential loses torque transmission capability when one wheel slips
Solution Approach 1:
The clutch mechanism dynamically adjusts its engagement state based on operating conditions. During normal operation, it allows free rotation for differential action; during wheel slip, it engages to lock the wheels together, maintaining torque transmission. This dynamic adaptability resolves the contradiction between allowing speed differences and maintaining torque transmission during slip.
Solution Approach 2:
The system changes the engagement parameter of the clutch based on detected wheel slip conditions. When slip is detected, the clutch engagement parameter changes from disengaged (allowing differential) to engaged (locking torque transmission), thereby maintaining reliability during varying operating conditions.
3Reliability
If locking functions are added to differentials to prevent torque loss during wheel slip, then torque transmission reliability improves, but the differential becomes even more bulky and expensive
Solution Approach 1:
The locking function is merged with the clutch mechanism already integrated in the hydrostatic transmission. The same clutch that enables differential operation also provides the locking function when engaged, eliminating the need for separate locking mechanisms and reducing system volume and cost.
Solution Approach 2:
The clutch mechanism serves as a universal component that performs both differential operation and torque locking functions. By making the clutch multi-functional, the patent avoids adding separate mechanisms for each function, thereby preventing increase in system volume and cost while maintaining torque transmission reliability.
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 provides a compact and efficient torque transmission system that maintains functionality even when one wheel slips, avoiding the bulkiness and cost issues of conventional differentials while enabling adaptive speed differentials, thus enhancing vehicle maneuverability and performance.
Implementation Method 1
the application of hydraulic pressure on said cylinder block causes a translation of the cylinder block against the clutch and the switching of the clutch
Implementation Method 2
the first set of discs engages the left set of discs and the second set of discs engages the right set of discs so as to link the left shaft, the right shaft and the rotating part of the machine hydraulically
Data Source
Figure 1a
Figure 1b
Figure 2a
AI summary
The present invention relates to a system comprising a hydraulic machine (M2) comprising a fixed part and a rotating part to create a hydrostatic transmission, the rotating part of the machine comprising a cylinder block (140), the system comprising a right-hand shaft (22) and a left-hand shaft (21) which are independent, characterized in that said hydraulic machine (M2) comprises a clutch (170) connected to the rotating part thereof, the clutch (170), the right-hand shaft (22) and the left-hand shaft (21) being designed to collaborate in such a way that said clutch alternates between: - a coupling configuration in which the left-hand shaft (21) and the right-hand shaft (22) are connected for rotation to the rotating part of the hydraulic machine (M2), - a freewheel configuration in which the left-hand shaft (21) and the right-hand shaft (22) are free to rotate relative to one another and relative to the rotating part of the hydraulic machine (M2).