We develop a belt drive in nanoCAD Mechanics 21.0 (part 1 of 3)
Introduction
I knew that a new version of the nanoCAD Mechanics program was being prepared for release back in 2020. The developers “frightened” the new functionality, but they did not say what kind of functionality it was and asked to wait a little: “When we release it, you will see, you will like it.” The year 2021 has come, the New Year holidays are over, but there is still no version. Well, then the work started and I even forgot a little about the upcoming new product, until a letter with the announcement of the long-awaited release fell in the mail. The very next day, the developers of the program sent a fresh distribution kit and a brief description of the innovations. It was suggested that you familiarize yourself with a completely new functionality for working with sheet bodies. New is always interesting and exciting. In addition, not long before that, I received a task to develop a 3D model of a fan belt drive, in which there are just a couple of elements from a bent sheet. By and large, the process of creating these very elements in version 20 is absolutely clear and does not represent anything supernatural, and it so happened that by the time I started studying the new capabilities of version 21, I had not yet started them, but dealt with details with more complex shapes. Of course, I immediately wondered what the new functionality would give, how it would simplify (or vice versa) the process of modeling sheet elements, and what result I would see at the output. But let’s leave the lyrics and see what happened in the end.
Brief description of the simulated product
As I mentioned, I was tasked with developing a belt drive model for a fan. This node, although small, combines many different parts that are interesting from the point of view of using the program tools: bodies of revolution, extrusions, standard products, shafts, bent plates, etc. (fig. 1).
The drive model consists of 129 elements. Some of them are the same, but there are even enough unique ones to tell about each in this article. Actually, such a goal is not set. Here I want to share the experience of modeling several parts, which, perhaps, will be most interesting to the reader in the context of the new functionality for working with sheet 3D solids.
Description of the manufacture of sheet elements
In the developed transmission model, the main bearing part – the plate – is a bent sheet with a large number of holes of various shapes (Fig. 2). Let’s build it.
To begin with, draw a sketch of the part in the XOY plane. So far, this is an ordinary rectangle of arbitrary sizes. Constraints must be applied to define the exact dimensions. Go to the appropriate ribbon, select the sketch and click the Auto Constraint button. The program will set initial geometric constraints between sketch segments. If necessary, they can be corrected both by adding missing ones and removing unnecessary ones. Next, we add parametric dimensions: the length and width of the plate, as well as anchors to the origin, which we will position in the center. For this we choose Linear dimension and indicate the corresponding dimensions. The length of the plate is 530 mm. Let’s call this parameter L. The width, let’s call it W, is 260 mm. Here you should pay attention that we do not set the width of the flat pattern, but the details in the plan. The bindings to the origin of coordinates will be set through the connection with L and W (Fig. 3).
As a result, we get a parametrized sketch of the plate, in which the insertion point will always be in the center, regardless of the size.
After that, go to the tape 3D Tools, turn on the simulation mode Sheet and in the section Leaf bodies push the button Sheet body (Fig. 4), select the sketch (Fig. 5) and set the thickness of the plate. Further, when working with sheet bodies, I will use the commands from the panel Leaf bodies ribbons 3D Tools, so for the sake of brevity I will limit myself only to the names of the commands.
As a result, we get a body similar to the extrusion body (Fig. 6).
What is the salt? But in what – I will bend it! We execute the Bend by edge command (Fig. 7) and indicate the edge from the bend side. The program immediately created a fold with the default settings.
In the dialog box, we see a fairly impressive number of bend parameters, grouped into six categories. I will focus on those that I will change.
Fold Continuation Category (Figure 8). Here we set the type of length Outer contour and the length value according to the drawing – 50 mm.
In addition to the type of length Outer contour, other options are available (Fig.9a-d):
Length from outside tangent – length from the outer tangent fold line to the edge of the fold
Length from inside tangent – length from the inner tangent line of the fold to the edge of the fold
Length from outer contour – length from the point of intersection of the outer bend contour lines to the edge of the bend
Length from inner contour – length from the point of intersection of the lines of the inner contour of the bend to the edge of the bend
In the Angle and radius category (Fig. 10), we only change the bend radius. It should be 8mm, radius type – Interior…
In the Bend Placement category (Fig. 11), set the bend formation method – Bend line outside. In essence, this is the alignment of the folded part relative to the edge of the original plate. In this way, we place the fold within the required dimensions of the part.
Leave the rest of the parameters by default. We repeat the fold on the opposite side and get the required bent plate (fig. 12).
To be continued…
Sergey Stromkov
engineer of the first category
ArkSoft company
arcsoft.ru