Auxiliary Power Take-Off Assembly with Decoupling Switching Element

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Solution Overview

Problem

Existing power take-off arrangements with torque converters in vehicle transmissions suffer from increased noise, rolling losses, and a larger, heavier design due to constant rotation of transmission components, even under low loads, and require a large clutch and associated actuators.

Innovation Solution

A power take-off arrangement where the switching element is operatively arranged between the drive shaft and the drive element of the transmission chain, allowing for complete decoupling from the further transmission chain and auxiliary unit, eliminating unnecessary rotation and noise, and omitting the clutch in the output element to reduce size and weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the transmission chain runs constantly with the drive shaft rotation, then the power take-off can transmit torque continuously, but rolling losses and acoustic excitation increase

Engineering Contradiction:
Improvecontinuous power transmissionVSAvoidrolling losses
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent applies a dynamic switching element (clutch) that allows the transmission chain to be engaged or disengaged from the drive shaft based on operational requirements. When disengaged, the transmission chain components remain stationary or rotate minimally, eliminating rolling losses while maintaining the capability for continuous power transmission when needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The switching element is positioned between the drive shaft and the drive element, allowing the transmission chain to be extracted or decoupled from the drive shaft rotation. This separation enables the power take-off to operate independently from continuous drive shaft rotation, reducing energy losses when the auxiliary unit is not in use.

Inventive Principle:
Principle #2Taking out (Extraction)

2Power

If the transmission chain runs constantly with the drive shaft rotation, then the power take-off can transmit torque continuously, but acoustic excitation increases

Engineering Contradiction:
Improvecontinuous power transmissionVSAvoidacoustic excitation
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The dynamic clutch allows the transmission chain to be engaged only when power transmission is required. When disengaged, the gears and transmission components are stationary, eliminating acoustic excitation from constant meshing and rotation, while maintaining the capability for continuous operation when needed.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If the switching element is arranged in the output element, then the auxiliary unit can be decoupled, but the clutch and actuators become large and heavy

Engineering Contradiction:
Improvedecoupling capabilityVSAvoidclutch and actuator weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The switching element is positioned as an intermediary between the drive shaft and the drive element, rather than in the output element. This intermediate positioning allows for a more compact clutch design with smaller actuators, reducing weight while maintaining the decoupling capability. The switching element acts as a mediator that enables auxiliary unit disconnection without requiring large components in the output path.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Adaptability or versatility

If the switching element is arranged in the output element, then the auxiliary unit can be decoupled, but the power take-off arrangement becomes large and heavy

Engineering Contradiction:
Improvedecoupling capabilityVSAvoidpower take-off arrangement weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of stationary object

Solution Approach 1:

By positioning the switching element between the drive shaft and drive element rather than in the output element, the patent creates a more compact power take-off arrangement. This intermediate positioning reduces the overall size and weight of the system while preserving the ability to decouple the auxiliary unit when not in use.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3481660B1Auxiliary power take-off assembly
Publication Date: 2020.09.16 ZF FRIEDRICHSHAFEN AG
  • EP3481660B1 patent drawingFigure 1
  • EP3481660B1 patent drawingFigure 2
  • EP3481660B1 patent drawingFigure 3

AI summary

The invention relates to an auxiliary power take-off assembly (32) for a transmission (6) of a motor vehicle (2), said transmission having a torque converter (8), which auxiliary power take-off assembly has an input shaft (30), which is permanently connected to a drive motor (4) of the motor vehicle (2) by means of the pump shaft (24) of the torque converter (8). Furthermore, the auxiliary power take-off assembly (32) has a transfer chain, which consists at least of an input element (34) and an output element (42) and the output element (42) of which is connected to an auxiliary unit (66) to be driven, and has a switching element (64, 68). The switching element (64, 68) is operatively arranged between the input shaft (30) and the input element (34) of the transfer chain in order to selectively connect the input shaft (30) to the input element (34).