Rail Vehicle Gearbox Thrust Collar Axial Force Management
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Solution Overview
Problem
Transmission arrangements with helically toothed spur gears in rail vehicles face challenges in absorbing axial forces and ensuring adequate lubricant supply, particularly with the use of cylindrical roller bearings, which can lead to damage and lubricant deprivation during frequent start-stop operations.
Innovation Solution
The implementation of pressure collars or thrust washers on the drive pinion and output gear, designed as pressure disks or L-shaped washers, to absorb axial forces and maintain lubricant supply through a raised sump system, ensuring continuous lubrication even during stationary periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If cross-roller bearings (tapered roller bearings or axial bearings) are used to absorb axial forces, then axial forces are effectively absorbed, but complex adjustment and readjustment work is required during assembly and maintenance
Solution Approach 1:
The invention extracts the axial force absorption function from the bearing system and assigns it to a dedicated thrust washer component. The thrust washer is specifically designed to handle axial forces while the cylindrical roller bearings focus on radial loads, eliminating the need for complex bearing adjustments.
Solution Approach 2:
The bearing support system is segmented into two functional components: cylindrical roller bearings for radial load support and thrust washers for axial force absorption. This functional segmentation allows each component to be optimized for its specific purpose, simplifying the overall system.
2Force
If pressure collars are used to absorb axial forces with cylindrical roller bearings, then axial force absorption is achieved, but adequate supply of lubricant to the contact area becomes problematic
Solution Approach 1:
The invention positions the thrust washer at the outer circumferential area of the pressure collar, utilizing the radial dimension to access lubricant from the sump. This dimensional positioning ensures the lubricant contact area remains exposed and accessible even when the gear is stationary.
Solution Approach 2:
The thrust washer design allows the lubricant supply system to serve itself by positioning the contact area where lubricant naturally accumulates in the sump. The system automatically ensures lubrication without requiring additional active lubrication mechanisms.
3Force
If the contact area is positioned at the inner circumferential area of the pressure collar, then axial forces are absorbed, but the lubricant supply becomes insufficient during stationary periods
Solution Approach 1:
The contact area is repositioned from the inner circumferential area to the outer circumferential area of the pressure collar. This dimensional change places the contact area in a region that remains exposed to lubricant in the sump even when the gear is not rotating, ensuring continuous lubrication.
Solution Approach 2:
The thrust washer is designed to maintain lubricant film presence in advance of operation by positioning the contact area where lubricant naturally resides in the sump. This preliminary positioning of the lubricant film prevents film breakdown during subsequent stationary periods.
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 effectively absorbs axial forces and maintains a consistent lubricant supply, preventing lubricant film breakdown and ensuring reliable operation during frequent start-stop cycles and maintenance, thereby reducing the risk of gearbox damage.
Implementation Method 1
the contact area between the thrust washer and the output gear is formed on the mutually facing axial-side peripheral area of the two components along the respective toothing engagement
Implementation Method 2
the circumferential area of the thrust washer attached to the drive pinion is immersed in lubricant at least in sections for supplying lubricant to the contact area
Data Source
Figure 1~2
AI summary
The invention relates to a gearbox arrangement for a rail vehicle, with at least one pair of spur gears having helical toothing, said arrangement comprising a drive pinion (1) and a drive wheel (2), which are mounted by means of cylindrical roller bearings (5, 5A) in a gearbox housing (4), wherein at least one thrust collar for absorbing axial forces via a contact area (8, 8A) is arranged on at least one of the spur gears, and wherein each thrust collar is substantially designed as a pressure plate (7, 7A) such that lubricant is applied, at least in certain sections, to the contact region (8, 8A) provided on the peripheral region of each pressure plate, independently of the rotational movement.