Gear type and properties

Tooth spacing

Especifica la separación entre centros de los dientes, tal como se mide a lo largo del diámetro de paso de marcha.

Type

Esto selecciona qué tipo de dientes de engranaje para dibujar. Los dientes de los engranajes pueden ser rectos, molinillo de viento, o transportador de ángulos.

Involute

Esto especifica engranajes rectos evolvente. engranajes rectos evolvente son el tipo más común de engranajes. Cualquiera de los dos engranajes que tienen el mismo espaciado de los dientes (o tono) y el mismo ángulo de contacto (también conocido como ángulo de presión) se malla y funcionar sin problemas.

PinPara algunas aplicaciones, es deseable que un engranaje se compone de un anillo de pasadores. Tales engranajes son también conocidos como engranajes "linterna". Los pasadores están normalmente unidas por dos discos en cada lado, de modo que toda la estructura se puede decir que se parece a una "linterna". un engranaje de este tipo puede o no puede tener un eje que pasa por el medio de los pasadores.

La ventaja principal de este tipo de arte es que es posible hacer marchas con tan sólo tres dientes que aún se ejecutará sin problemas.

Molinete para engranajes, el engranaje de la derecha será siempre el molinete y el engranaje de la izquierda siempre será la forma cicloide para acoplarse con el molinete.

ProtractorA veces es útil ser capaz de crear una plantilla que divide un círculo en un número específico de intervalos. Por ejemplo, para dividir un círculo en 23 partes iguales con un transportador sería

tedioso y propenso a errores. Usando este programa usted puede imprimir una plantilla que divide el círculo como se especifica.

Shaft spacing

Este campo siempre muestra el valor de espaciado del eje calculado. La separación del eje es la suma de los radios de paso de ambos engranajes. radio de paso se calcula a partir de la circunferencia terreno de juego. Pitch circunferencia es igual al número de veces que los dientes el espaciado de los dientes.

También puede introducir un nuevo valor en este campo y la separación de los dientes del engranaje será automáticamente calculada para producir el centro deseado para centrar la distancia de los dos engranajes.

Contact angle

Este campo especifica el ángulo de contacto, también conocido como ángulo de presión, para engranajes de dientes rectos de evolvente. Los ángulos de contacto más grandes producen engranajes que tienen más dientes triangulares que buscan. Los ángulos de contacto más grandes funcionan mejor para engranajes con un pequeño número de dientes, pero el resultado global es menor eficiencia debido a una mayor fricción en el conjunto de engranajes.

Este campo sólo es aplicable para los dientes rectos de evolvente y se oculta, si se seleccionan otros tipos de dientes del engranaje.

Pin diameter

Este campo especifica el tamaño de los pines para engranajes molinete. Este campo sólo es aplicable a la clavija de engranaje de la rueda y no se podrá ver si se seleccionan otros tipos de dientes del engranaje.

Gear properties

Esta sección le permite especificar los parámetros específicos para cada marcha.

Show

Seleccione si la marcha es visible. Tenga en cuenta que para los engranajes del molinillo de viento, las propiedades del molinete afectan a la forma del engranaje de acoplamiento, por lo que incluso si el equipo adecuado está oculto, sus propiedades aún afectan a la marcha a la izquierda.

Spur

Selecciona un engranaje recto regular. Esto es, un engranaje redonda con dientes en el exterior.

Ring

Selecciona una corona dentada. Un engranaje de anillo es un engranaje con dientes en el interior. Modo circular sólo se puede seleccionar si el otro engranaje es un engranaje recto. coronas dentadas son útiles al hacer conjuntos de engranajes planetarios

Rack

Selecciona un engranaje de tipo "cremallera". Un rack es esencialmente un engranaje que se ha desenvuelto. Rack y piñón modo sólo está disponible actualmente para este tipo de diente de evolvente.

TeethEspecifica el número de dientes del engranaje.

AddendumEspecifica la adición de los dientes. La adición es la cantidad de diente de la rueda sobresale fuera de su diámetro de paso. Se especifica en relación con el espaciado de los dientes. Esto es, un ajuste

Odd shaped gears generated by setting the right side gear addendum to zero.

de 0,25 significa que la adición de un diente será un cuarto de la separación, o aproximadamente la mitad de su anchura.El dedendum engranaje (es decir, el nivel de profundidad de corte más allá del círculo de paso entre los dientes) se toma de adición del engranaje de acoplamiento. Así que para establecer el dedendum de un engranaje, acaba de establecer la adenda correspondiente del apareamiento gear. 

Note that cycloid gears don't use the addendum parameters.

Spokes & more tab

Diametric pitchAlgunas personas prefieren utilizar terreno de juego diametral, a diferencia de espaciado de los dientes (también conocido como paso circunferencial). paso diametral es igual al recuento de los engranajes de dientes, dividido por el diámetro de paso, por lo que este número varía inversamente con el tamaño de diente. Tenga en cuenta que la versión 2 y anteriores del generador de engranajes calculada esto como diámetro por diente (inversa de lo que debería ser). Puede introducir un valor en el terreno de juego diametral, y el paso circunferencial en la pestaña principal se actualizará automáticamente.

SlopThe amount of total slop, play, or tolerance. With slop set to zero, the gears are printed so that they fit exactly, with no tolerance for slop. Usually, the width of the cut on the bandsaw or scroll saw will provide enough slop, but you can also add slop by setting this parameter.

Right angle thickness adjustWhen making 90 degree gearing, with your saw table tilted by the gear's contact angle, this field is used to tell the gear program how

thick your material is, so that the teeth can be "fattened" by the right amount so that the bevel cut will result in gears of the right thickness. This parameter is ONLY used for involute spur gears.Please see my article on right angle gearing on how to use this. This feature was added for version 3.1.0 (Feb 2015). If you have an earlier version 3.0.x, click on "help" in the program to get the latest version.

Pitch diameterThe pitch diameter is the diametric pitch times the number of teeth. The pitch diameter is useful for working out gear spacing. The ideal center to center distance of a pair of gears is equal to the sum of the pitch diameters, divided by two. Note that the shaft spacing in the "Gear properties" tab already shows the center to center distance as "shaft spacing".

Overall diameterThis displays the overall diameter of the gear, from tip to tip.

SpokesSpecifies the number of spokes. Only spur gears above a certain number of teeth are large enough to have spokes.

Shaft hole diameterSpecifies the shaft hole to draw. For pinwheel (lantern) gears, this specifies the size of the shaft in the middle of the pins. The gear teeth of the mating gear will be kept short enough so as not to interfere with the central shaft. Specify zero to omit the center shaft or shaft hole.

Chain & Sprocket modeThe gear template generator version 2.0 includes a "chain and sprocket" mode. This mode is intended to assist in generating sprocket shapes for wooden block chains and roller chains.

Chain & sprocket mode is turned on by selecting the "Chain & Sprocket" tab on the bottom left of the main window. 

Block chain Roller chain

The gear template generator can produce both block chain sprockets, and roller chain sprockets.

Nearly all modern metal drive chains, such as those used on bicycles, are of the "roller chain" variety. Roller chains have a cylindrical roller on every pin joint, with two sets of links on either side to join them together.

Block chains are an older, obsolete style of drive chain. Block chains are much simpler to make, and lend themselves well to wood. In a block chain, the sprocket engages bocks in the middle of the chain. Each block has two holes, to which

the links on either side attach. An example use of a wooden block chain can be seen in this tank thread vehicle 

If the blocks of a block chain are not rounded on the corners, then the corners tend to scrape the sprocket where the chain engages and disengages the sprocket.

The gear template generator will generate sprocket shapes that make allowances for this "undercut" next to the teeth for this, but the sprockets are still somewhat ugly and inefficient. 

A much better solution is to put a bit of a round or chamfer on the edges of the chain blocks. The sprocket at left is very similar to the previous sprocket, but with blocks that have chamfered corners. Note that the teeth have much less undercut.

For clarity, I changed the links to be very thin, but the links do not actually engage the sprocket, so only the link's length, not its actual shape contributes to the sprocket shape. 

The gear generator can generate shapes for workable sprockets down to three teeth. However, these sprockets are inefficient and will run very rough. If you use the "Animate" function in the gear template generator, you can see that the chain has quite a bit of side-to-

side motion.

The shape of the teeth also doesn't engage the chain very well, as the teeth need to be very sloped to allow the chain to engage and disengage the sprocket. 

Sprockets with larger number of teeth will run much more smoothly. 

To better see how the chain meshes, parts of the chain and sprocket can be hidden. The image at left, for example, has the chain links hidden. You can also hide the chain entirely. Hiding the chain is useful when making a printout of the sprocket template shape to use when cutting the sprocket out of plywood.

The image at left also has the "Show pitch diameter" turned on. The blue lines represent the pitch diameter, and the lines crossing it indicate the centers of the tooth undercut radii. If you have the right size drill, you can start by drilling out the undercut circles, which will make it easier to cut out the rest of the sprocket with a bandsaw 

Specifying the chain dimensions

The shape of the sprocket teeth is generated based on the shape of the chain blocks, and the length of the chain links.

The shape of the chain blocks and links is specified in terms of length and width. Please note that the specified length is the length between the two

holes. The program automatically adds some length to the link to allow for material around the holes.

An additional parameter, "Chamfer" determines how much to remove from each corner of the blocks and links. If "Round chamfers" is selected, the chamfer is replaced by a round with a radius equal to the chamfer measure. 

Display parameters

This part of the panel selects which aspects of a gear to display.

Show pitch diameterWhen selected, a circle is drawn indicating the gear's pitch diameter.

Show line of contactFor involute teeth, this shows the contact angle (pressure angle) and base radii of the two gears. If you think of the base radii as being two spools, a point along a string unwound from the right gear's base radius and wound onto the left gear's base radius would exactly follow the path along which both gears touch.

Show centerShow a crosshair in the center of each gear.

Draw thicker linesDoubles the thickness of lines used to draw the gear, so that the lines snow up better on printouts..

Draw unmeshedIf both gears fit on one page, select this option to draw the gears separated so that when you print them, you can cut the two shapes out separately. Also useful for CAD exporting both gears at the same time.

Fewer line segmentsApproximate the round curves of the gears with fewer line segments. The difference is not noticeable at a glance, but when exporting and importing into other programs, some programs have difficulty with the number of line segments that the gear program creates.

GridDraw a grid. The grid is useful for getting a sense of scale, for checking that a printout was scaled correctly, and to help align multiple pages together when pasting together multi-page printouts.

Grid diagonalsDraw diagonal lines on the grid. Diagonal lines are very useful to help align the sheets of a multi-page printout when gluing the pieces of paper together. The diagonals grids work so well, I later wrote BigPrint to allow other types of images to be pasted together this way.

AnimateSlowly turn the gears. This allows you to examine how the gears mesh. Note that spur gears with less than 10 teeth and low contact angles will often cause interference. For gears with very few teeth, try pinwheel gears.

WobblyI implemented "wobbly mode" for the evaluation version of the program. The eval version can do everything the full version can do, but all output is distorted. The distorted gears would not work in real life.

I found the distorted "wobbly mode" fun to watch, so I have added this "feature" as an option to the full version as well, just for fun.

Show rotatedThis field causes the gears to be displayed rotated. The angle is specified as one hundredths of a tooth. Specifying 25, for example, will cause the gears to be rotated by one quarter tooth interval.

This feature is useful if you want to check that spur gears mesh without interference. It's especially useful if you use the up/down buttons, and zoom in on the meshing point by reducing the value of the "screen view width" field.

Screen view widthThis field indicates how wide an area the screen represents. This value defaults to 20 cm, or about the width of the printable region on a normal piece of paper.

Note that this value is in whatever units you chose. If you change the units to "inches" then the visible region would change to 20 inches, along with all other dimensions. The display would not change, but when you print it, it will now be much larger as it's now sized in inches.

Saving

The parameters for a gear can be saved in a file for later reloading. The parameters are simply stored in a text file. If a file called "default.gear" exists in the same directory as the program, it will be loaded automatically when the program starts.

Units

Units can be selected to be inches, centimeters or millimeters. Note that the displayed gear's size does not change if the units are changed. A gear that is 10 cm across, when you change the units to inches, will now be 10 inches across. The screen width would also change from 20 cm to 20 inches. However, on printing or exporting, the gears will be scaled accordingly. Note, however, that on importing DXF, the units are not specified inside the file. Typically, one must indicate to the importing program what units are represented in the file.

PrintingThe gear template generator is able to print gears that span many pages. If a gear does not fit onto a single page, then the gear is split across multiple pages to be printed and then glued together.

Grid lines, especially when combined with diagonal grid lines, are very useful to help precisely align the pages when gluing them together.

It's advisable to do a print preview before printing your gears. The dimensions you have specified might result in gears that span a surprisingly large number of pages.

Printing parameters

Printer scale calibrationYou may find that your printer prints just slightly larger or smaller than it should, especially if your printer is a laser printer. If you find that 10 grid lines of a one centimeter grid are actually 10.1 cm horizontally, you can compensate by setting the width calibration to 99%. If you switch to "landscape" orientation, the "width" is actually the length. The labels adjust to reflect this.

Horizontal / vertical / overlapIf you print gears that span multiple pages, the gears are printed with no overlap by default. You may prefer to have a slight amount of overlap from page to page to give you more confidence in aligning the pages. You can either enter the overlap, or you can enter the spacing of the pages. Note that the spacing and size of the pages always total up to the printable area on a page.

You may also find that its quite easy to align the pages even without overlap when grid diagonals are enabled.

Print overlap areaYou can select whether to print in the overlapped area. This option is only enabled if an actual overlap is selected using the horizontal/vertical/overlap fields.

Center gears

Normally, the gears are in the top left of the page, or group of pages. If you check this, the gears will be centered on the page, or group of pages.

Print parametersIf checked, the actual gear parameters will be printed on the top left of the page.

ExportingWhen exporting to a file, everything that is drawn on the screen is exported. This included both gears, as well as any center and grid lines you may have turned on. It's recommended that you turn off everything but one gear and its center crosshair before exporting. Otherwise, it can be difficult to separate the gears from the grid in whatever program you are importing into.

No printer pagination will be applied to export.

DXF (with poylylines)Most CAD programs can import DXF files. The gear template generator's DXF export is relatively simplistic and only two dimensional, but it will get the shapes into your CAD program.

The DXF export does not include units. Programs that import DXF typically allow you to specify which units the DXF file actually uses. For example, if you used inches to design your gear, but the importing program assumes the units are millimeters, the imported gear will be much smaller than you expect.

Please note that DXF export with polylines for version 3.0.x is less than perfect and that AutoCad will not successfully import this. Version 3.1 improves DXF polyline export and works with AutoCad. Click on "help" in your program to update.

DXF (basic DXF)DXF is a very difficult to figure out format, and the DXF exported by the gear template generator may not be compatible with all programs. If the "with polylines" export does not work, try exporting as basic DXF. Basic

3D gear drawn from gear outlinein SketchUp

DXF exports line segments only. Unfortunately, this means some programs will not recognize the outline as a joined object.

SketchUpOne of the most popular CAD programs among woodworkers is the free SketchUp. However, the free version of SketchUp does not handle DXF import. It does, however, import data in "Collada" format. Because so many people use the free version of SketchUp, I implemented export to this format so that you can still import gears into the free SketchUp. As CAD programs go, SketchUp is relatively easy. But be warned. All CAD programs have a steep learning curve.

When you import a gear into SketchUp, it will be imported as nested objects. Keep opening the objects until you can select individual line segments of the gear outline. To turn the outline into a surface that can be extruded, draw a rectangle around the whole outline, then delete the outline of the rectangle. If your gear has spoke and center holes, select these with a double click, copy them, delete them, then paste them in place. After that, you will be able to delete the surface inside the spoke holes. I don't think SketchUp works as well as they say it should in this particular regard, but the above procedure has worked for me.

HPGLHPGL stands for "Hewlett Packard Graphics Language". It is the format used by the old HP plotters. Nobody uses plotters anymore, but the format is fairly straightforward and various pieces of software still know how to import and export graphics in this format.

CSV (for spreadsheet)CSV (Comma Separated Values) is the simplest form of export, consisting of just two columns of numbers, plus some annotation. This format can be loaded into spreadsheets such as Excel. You can display the gears as a graph in Excel by selecting the two columns of numbers and generating an X-Y scatter graph from the data.

Displaying gears in a spreadsheet is not particularly useful, but it's a good starting point if you wish to manipulate the X-Y points in some way for your own purposes.

Image (bitmap)Exports the image as a bitmap (BMP, Jpeg, or PNG). A window will pop up allowing you to specify how many pixels per size unit (pixels per inch, per centimeter or per millimeter), and whether antialiasing (line smoothing) is turned on.

PDFThe PDF export is intended for importing into laser cutters and such. The "page size" used is whatever is needed to print the gear. PDF export does not split the output across multiple pages.

If you need to create a PDF for printing across multiple pages on another printer, the best way to proceed is to print to a file. To print to a file, go to "configure printer" under print setup, and select "Microsoft XPS document..." as the printer. Then print. Windows will prompt you to specify a file to print to. Then upload the XPS file to http://www.xps2pdf.org/ to convert it to a PDF file. Note that this trick works with any program that can print to a printer. No need to install special software on your computer to create PDF files. There are also "printer drivers" available on the internet that allow you to print directly to a PDF file on your computer, such as the free Bullzip PDF printer driver , but printing to XPS and then converting doesn't require any extra software installation.

SVGSVG stands for scalable vector graphics. Some newer laser cutters and CNC routers are able to import SVG.

SVG was intended for screen graphics, and is sized in pixels. You have to enter how many "pixels" per unit of measurement your importing program expects. Otherwise, the object may not come out the right size. SVG export was added with version 3.1.1, March 2015.