Test Rig Differential Gear Stage for Gearbox Ratio Adaptation
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Solution Overview
Problem
Existing test rigs for gearboxes are inefficient in testing different gear ratios due to the need for oversized motors and generators, high installation costs, and inability to control test torque effectively in mechanical closed power loops.
Innovation Solution
A test rig with a differential gear stage, specifically a planetary gear system, that adjusts rotational speeds to compensate for gear ratios, allowing for controllable torque imposition on the gearbox under test, reducing the need for oversized components and enabling testing of gearboxes with varying gear ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If a mechanical closed power loop is used to reduce installation costs and energy consumption, then the drive motor size is reduced, but the ability to test different gear ratios is lost
Solution Approach 1:
The planetary gear mechanism introduces dynamic adaptability to the mechanical closed power loop. By varying the rotational speed of the planet wheel carrier relative to the sun gear and ring gear, the system can dynamically adjust the effective gear ratio to match different gearbox configurations, enabling versatile testing while maintaining the energy-efficient closed loop structure
Solution Approach 2:
The system changes the rotational speed parameter of the planet wheel carrier to compensate for different gear ratios of gearboxes under test. By adjusting this speed parameter, the planetary gear mechanism transforms the fixed-ratio mechanical closed power loop into an adaptable system that can accommodate various gearbox gear ratios
2Ease of operation
If an auxiliary worm gearing is used to control test torque, then torque control is achieved, but the test rig can only test gearboxes with certain gear ratios
Solution Approach 1:
The invention merges the torque control function (auxiliary worm gearing) with the gear ratio adaptation function (planetary gear mechanism) into a single integrated system. The planet wheel carrier serves dual purposes: it provides torque control through the auxiliary worm gearing while simultaneously adjusting the effective gear ratio through its rotational speed, resolving the contradiction between torque control and versatility
3Adaptability or versatility
If a planetary gear mechanism is added to adapt to different gear ratios, then versatility is improved, but device complexity increases
Solution Approach 1:
The planetary gear mechanism serves multiple functions simultaneously: it adapts the mechanical closed power loop to different gear ratios, provides torque control through the auxiliary worm gearing connection to the planet wheel carrier, and maintains the energy-efficient closed loop operation. This multi-functionality justifies the added complexity by resolving multiple contradictions at once
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 solution reduces energy consumption and installation costs by allowing the drive motor to supply only mechanical power losses, enabling efficient testing across different gear ratios with precise torque control.
Implementation Method 1
a differential gear stage having first and second rotatable elements (107, 108) which form part of the mechanical closed power loop and whose mutual rotational speed difference depends on rotational speed of a third rotatable element (109) of the differential gear stage
Implementation Method 2
The gear system comprises a differential gear stage having first and second rotatable elements which form part of the mechanical closed power loop and whose mutual rotational speed difference depends on rotational speed of a third rotatable element of the differential gear stage
Implementation Method 3
allowing the third rotatable element of the differential gear stage to rotate at such a speed that a speed difference of the first and second rotatable elements of the differential gear stage compensates for an effect of gear ratios of other elements
Implementation Method 4
The test rig further comprises a controlling device connected to the third rotatable element of the differential gear stage and arranged to control torque acting on the third rotatable element when the third rotatable element is rotating
Data Source
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AI summary
A test rig comprises a gear system (101) connectable to a gearbox under test, a power transmission shaft (104) such that the gear system, the gearbox (114) under test, and the power transmission shaft constitute a mechanical closed power loop, and a drive motor (105) arranged to drive the mechanical closed power loop. The gear system comprises a differential gear stage (106) for adapting the gear ratio of the test rig to correspond to the gear ratio of the gearbox under test. The differential gear stage comprises first and second rotatable elements which form part of the mechanical closed power loop and whose mutual rotational speed difference depends on rotational speed of a third rotatable element of the differential gear stage. Test torque is imposed to the gearbox under test by controlling the torque acting on the third rotatable element when the third rotatable element is rotating.