Gearbox Selection Control With Screw-Drive Actuation Against Friction
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Solution Overview
Problem
Existing gear line selection systems in gearboxes face issues with axial blocking and frictional blockages due to low actuation force from single-acting electromagnetic or electric cylinders, leading to incomplete gear shifting and selection line changes.
Innovation Solution
An arrangement featuring a rotary electric drive motor and a screw-nut assembly with an axially oriented actuating rod, providing sufficient torque for gear line selection and rotation, combined with an elastic return spring for reversing the control member to its initial position, overcoming frictional forces and ensuring smooth gear shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-acting electromagnetic or electric cylinder is used as the controlled actuator, then the device complexity is reduced and the actuator is simpler, but the actuating force becomes insufficient leading to axial blocking phenomena and inability to overcome friction
Solution Approach 1:
The patent replaces the single-acting electromagnetic or electric cylinder with a double-acting electric motor that can generate controlled forces in both directions. This substitution eliminates the axial blocking phenomena and insufficient actuating force while maintaining reasonable device complexity through electronic control mechanisms.
Solution Approach 2:
The patent changes the fundamental operating parameters of the actuator by transitioning from a single-acting system (one direction of force only) to a double-acting system (both directions of force). This parameter change enables the actuator to overcome friction in both selection directions and eliminate axial blocking phenomena.
2Volume of moving object
If the solenoid is sized with low actuating force, then the device size is reduced, but the return spring must be sized with low return force which is insufficient to overcome friction during gear line selection
Solution Approach 1:
The patent replaces the solenoid-return spring mechanical system with a double-acting electric motor system. This substitution allows for better force control in both directions without being constrained by the size-force tradeoff inherent in spring-based return mechanisms. The motor can provide sufficient return force independently of its size through controlled torque delivery.
3Device complexity
If friction between elements linked to the control member is present under load, then the system is simpler without additional lubrication mechanisms, but axial blocking phenomena occur and prevent return to neutral position
Solution Approach 1:
The patent replaces the passive friction-based mechanical return system with an active double-acting electric motor system. This substitution provides controlled force delivery that overcomes friction reliably in both directions, eliminating axial blocking phenomena and ensuring consistent return to neutral position without compromising system simplicity.
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 enables reliable and efficient switching between gear lines by providing sufficient actuation force and torque, reducing frictional blockages and ensuring smooth operation of the gearbox, allowing for precise control and reliable gear engagement.
Implementation Method 1
a screw-nut assembly which comprises: a drive screw which is rotated by the drive motor; and a drive nut which is screwed onto the drive screw
Implementation Method 2
a means for returning the control member to rotate in the other direction to its first angular selection position
Data Source
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AI summary
The invention proposes an arrangement that comprises a selection control member (10, 22) that is mounted so as to be able to rotate between first and second angular selection positions, a controlled actuator that applies an actuating force to the control member (10, 22) in order to cause it to rotate between its two angular selection positions; and an elastic return means for rotatably returning the control member (10) to its first angular position, characterised in that the controlled actuator comprises an electric drive motor (28) and a screw/nut assembly that comprises a drive screw (42) driven by the drive motor (28); and a drive nut (38) that is guided in an axially sliding manner, and that applies an actuating force to the control member (10, 22) in order to cause it to rotate in the first direction (S).