Shaft in Gearbox (static analysis)

[MA_11032494]

Good day to you sir 
I am trying to solve a similar situation for an intermediate shaft in a 2-stage gearbox but not modal analysis rather a simple von Mises  static analysis on the whole shaft length, would like to know how to adapt these loads and constraints and other idealizations to run a similar case, is it necessary to idealize all the whole bearing Assembly like this or just adding 2 spring idealization and a weighted link to the surface area of the acting bearing suffice, as far as the simulation is on the shaft, the consideration of gear teeth doesn't matter so applying torque on the disk with pitch diameter is satisfactory right ? i would like to know how to apply idealized torque on these 2 helical gears while i have 2 fixed bearing holding this shaft and enduring a preload in between. 
regards

[skunks]

please send a STEP file

[MA_11032494]

In this case, we have a two-stage gear assembly where intermediate gears (3 & 4) are mounted on a transfer housing. This transfer housing is fitted onto a stationary shaft, which is supported by two bearings. The stationary shaft itself is aligned on two holders, also using two additional bearings.

The current arrangement of the outer single-row bearing is causing a preload on our transfer housing. This preload is transmitted from a sleeve to a nut and then to the inner single-row ball bearing, which functions as a sliding bearing. The other bearing on the transfer housing acts as a fixed bearing. 

The purpose is to optimize and reduce the weight of this transfer housing, so the analysis is supposed to be done only on the transfer housing.

The calculation of the gear forces and fitment of bearing and gears on the housing is as below. But the problem is when I define force on one tooth, should I define contact interference or I just omit the teeth and consider a disk with pitch diameter ?

the other question is for the definition of the fixed and sliding bearing I idealize a point as an infinitely stiff spring (Point-surface) and connect it with the weighted link to the contacting circumference area of bearings and housing, but after that for the fitment pressure from bearing I exert the force on this same surface or it is wrong ? 

Force F23: [-242.65, 626.46, -228.01] N ,  %[Fr, Ft, Fa]
Force F54: [-181.99, -469.85, -171.01] N , %[Fr, Ft, Fa]
Force at bearing C: [808.04, -626.46, 399.02] N
Force at bearing 😧 [-383.41, 469.85, 0.00] N
Fitment Pressure for gear 3: 14.39 MPa
Fitment Pressure for bearing C: 30.15 MPa
Fitment Pressure for gear 4: 7.79 MPa
Fitment Pressure for bearing 😧 33.29 MPa
 

[skunks]

With this relatively complex model, I would start as simply as possible, i.e. without contacts at first, leaving out as much as possible. As soon as the simplest analysis is running and delivers plausible results, I would gradually increase the complexity, step by step.
I'll make a small model as soon as I have some time.

Bei diesem relativ komplexen Modell wurde ich zunächst so einfach wie möglich anfangen, also auf jeden Fall zuerst ohne Kontakte, dabei so viel wie möglich weglassen. Sobald die einfachste Analyse läuft und plausible Ergebnisse liefert, würde ich die Komplexität sukzessive steigern, Schritt für Schritt.
Ich mache mal ein kleines Modell, sobald ich etwas Zeit habe 😂

[skunks]

for the beginning?

[skunks]

info (old) as pdf

[MA_11032494]

Wunderbar Sir ! 
Almost I have solved most of the unclarities except these 2:   
You can exert radial [Fr] and axial [Fa] forces on the ring surface with the width of the gear that is in contact with the rotating component using WCS direction. and separately place a Moment based on Ft exactly like the picture ? 

and the other question I have is when i define the bearing I idealize a point as an infinitely stiff spring (Point-surface) and connect it with the weighted link to the contacting circumference area of bearings and housing, but after that for the fitment pressure from bearing I exert the force on this same surface or it is wrong ?

 

[skunks]

I would not dispense with the gears, but introduce all 3 force components at the tooth, otherwise something might be lost? For example, the axial force on the tooth generates bending moment etc. Then the units are not optimal, better Newton basis. I would simply consider the bearings as you intend for the optimization. At the end, however, when the geometry is fully optimized, calculate with real bearings for checking purposes.

Ich würde auf die Zahnräder nicht verzichten, sondern am Zahn alle 3 Kraftkomponenten einleiten, sonst geht vielleicht etwas verloren? Z.B. die Axialkraft am Zahn erzeugt Biegemoment usw. Dann sind die Einheiten nicht optimal, besser Newton Basis. Die Lager würde ich so wie Du vorhast für die Optimierung einfach betrachten. Am Ende aber, wenn die Geometrie fertig optimiert ist, dann mit echten Lagern rechnen, zur Kontrolle.

[AndrewK]

Hi @MA_11032494 and @skunks,

Thank you both for the great discussion!

@MA_11032494 I wanted to follow up with you to see if your question has been answered. If so, please mark the appropriate reply as the Accepted Solution for the benefit of other members who may have a similar question.

Of course, if you have more to share on your issue, please let the Community know.