Planetary Multi-Stage Transmission Compact Design
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Solution Overview
Problem
Hybrid multi-speed transmissions with an additional pre-transmission for electric machines require significant installation space, increasing production costs and consumption.
Innovation Solution
A multi-speed transmission with integrated planetary gear sets, where the electric machine is connected via a fixed, gear-independent transmission ratio, allowing for a pre-ratio within the transmission, reducing the need for an additional pre-transmission and enabling a more compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If an additional pre-reduction gear is used for the electric motor, then the electric motor can be designed with lower torque, but the installation space increases significantly
Solution Approach 1:
The patent combines the pre-reduction function into the existing planetary gear set structure. The electric motor is connected to the ring gear while the sun gear is connected to the transmission input shaft, creating an integrated pre-reduction mechanism within the transmission housing rather than adding a separate pre-reduction gear assembly.
Solution Approach 2:
The planetary gear set serves multiple functions simultaneously: it provides the pre-reduction for the electric motor, enables gear ratio changes through shift elements, and facilitates reverse gear operation. This multi-functionality eliminates the need for dedicated separate components for each function.
2Force
If an additional pre-reduction gear is used for the electric motor, then the electric motor can be designed with lower torque, but the manufacturing costs increase
Solution Approach 1:
The pre-reduction function is merged into the existing planetary gear set, eliminating the need for separate pre-reduction gear components. This reduces the total number of parts, simplifies assembly procedures, and lowers manufacturing costs while achieving the same torque reduction effect.
Solution Approach 2:
The planetary gear set is designed to perform multiple functions including pre-reduction, gear shifting, and reverse gear operation. This universal design reduces the overall component count and manufacturing complexity compared to having separate dedicated mechanisms for each function.
3Force
If an additional pre-reduction gear is used for the electric motor, then the electric motor can be designed with lower torque, but the energy consumption increases
Solution Approach 1:
The integrated planetary gear set reduces mechanical losses by eliminating the need for additional gear meshing stages that would be required in a separate pre-reduction gear. The direct integration minimizes the number of power transmission interfaces, thereby reducing energy loss.
4Speed
If the electric motor is connected via a fixed gear-independent transmission ratio, then the electric motor can be designed with higher speed, but the transmission structure becomes more complex
Solution Approach 1:
The fixed transmission ratio for the electric motor is achieved by integrating the motor connection into the existing planetary gear set structure. The sun gear, ring gear, and planet gears work together to provide the fixed ratio, eliminating the need for additional fixed ratio gear stages and maintaining structural 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
This solution allows for a more compact and cost-effective design, enabling the electric machine to be designed with less torque but higher speed, saving space and components, and providing high starting torque for both forward and reverse travel without the need for a mechanical reverse gear.
Implementation Method 1
several planetary gear sets (RS1, RS2, RS3) in a single housing (9)
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a planetary multi-stage transmission in a housing (9) for a vehicle, comprising at least one electric machine (EM) and three planetary gear sets (RS1, RS2, RS3), wherein an input (An) can be connected to a first shaft (1) by means of a shifting element (K0) and an output (Ab) is connected to a second shaft (2), wherein four further shafts (3, 4, 5, 6) and at least five shifting elements (B1, K1, K2, K3, K4) are provided, by means of the actuation of which shifting elements at least eight forward gears (G1, G2, G3, G4, G5, G6, G7, G8) can be realized. According to the invention, the first element of the first planetary gear set (RS1) is connected to the housing (9), wherein the first shaft (1) is connected to the second element of the first planetary gear set (RS1) in a fixed manner, wherein the rotor (10) of the electric machine (EM) is connected to the third element of the first planetary gear set (RS1) and wherein the third element of the first planetary gear set (RS1) can be connected to at least one element of at least one further planetary gear set (RS2, RS3) by means of at least one shifting element (K3, K4).