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Say you’re3D打印机器人，并且您正在设计一个甜齿轮系统，以使机器人流畅地移动。如何处理大多数事实CAD程序没有“创建刻痕的齿轮”按钮吗？Welp，您必须手动创建这些几何形状。在本教程中，我会引导您完成此过程SolidWorks, and you can use a similar system for any other program.
在CAD程序中创建刻薄的齿轮是很棘手的，但是如果您按照以下步骤操作，则每次牙齿都会出现。慢慢走，确保您仔细跟随每个步骤，并且很快就可以准备好打印的好装备！
Step 1
For our example, we want to create a 19-tooth 32-pitch gear. We know that the pitch diameter of the gear will be 19/32 inches, which equals 0.59375 inches, but because we can keep equations in CAD, we’ll just create our first circle with a diameter of “=19/32”, as shown in the picture below. (I recommend using the top plane for all these sketches.)
Step 2
We want to create the edge of the tooth as if it were a point on the imaginary string unwinding from our post. To do this, in a new sketch on the same plane, we first create a horizontal line at the top of the circle, and then create a line with the pressure angle (20 degrees, since that’s common) which passes through the top of the circle, so we end up with a sketch that looks like the one below.
Step 3
在同一草图中，在第一个（同心）内部创建一个与20度（压力角）线相切的圆，然后从圆的中心到压力角线和内部的交点圆圈。（圆和线都以蓝色突出显示。此步骤的圆圈变成了“基本圆”：围绕弦的虚构柱。）
第4步
In this step, we’ll finally create the “string” for the involute, imagining the edge of the tooth to be this string unwinding. In another new sketch on the same plane, create a line along the pressure angle line from the base circle to the pitch circle, as shown below, and dimension it with a driven dimension. (The actual length of this is determined from the pitch and number of teeth of your gear, so it must be a driven dimension, but we’ll need the dimension on there to use in equations in the next steps.)
第5步
Now, we’ll imagine the string unwinding from our base circle and see the curve a point on the string would make. This will be an approximation but will be close enough for a printed gear, and you can make the approximation more accurate by choosing smaller increments for your approximated points.
Draw an arc that goes from the point where the “string” contacts the base circle to a little to the left, coradial with the base circle. Dimension this arc with an弧dimension (select both the end points and then the arc itself, otherwise you’ll end up with achord dimension, which just measures the straight-line distance between the arc endpoints) and give it the length of the increment you want for approximating the involute curve. (I recommend using a length about the pitch or module, in this case 0.03, though remember that smaller increments create more accuracy, and larger increments are fine for rougher approximations.)
第6步
Draw a construction line from the left end of the new arc towards the right, and make the line tangential to the base circle (also tangential to the arc). We’ll call this line the “string plus one” line.
步骤7
尺寸这条新线路。在弹出的尺寸框中（不是左侧的区域），键入“ =”;单击第一个直线字符串的尺寸（在这种情况下为0.10153723）;类型“+”;然后单击弧的尺寸。
结果应该类似于下面的一盒;click on the green check mark to accept. (The reason for this is that the arc represents the string unwinding from the cylinder, and so the end of the string gets longer by that amount as it unwinds to this new location.)
第8步
在当前弧的两侧创建更多弧，每个弧都相同弧lengthas the first. To do this quickly, draw the arcs; dimension the arcs (selecting each end and then the arc itself); type “=” in the pop up box; and click on the dimension of the first arc.
步骤9
从下一个弧到左侧，创建另一个与基本圆相切的施工线。这代表了弦乐的弦，因此应该是步骤6和7的“字符串和一条”线的长度，以及弧的长度。
通过单击该行，在弹出的框中键入“ =”，单击“字符串加一个”行的尺寸，键入“+”，然后单击ARC的尺寸。该行将称为“字符串加两个”行。
Step 10
Repeat step 9 for three new unwinding strings to the left. Each of these lines should be the length of the next string to its right, plus the arc length between them. Because these represent the string unwinding, this makes sense with the image of the string around a cylinder.
Step 11
现在我们需要创建字符串的行赢ding from the original location onto the cylinder till it ends. From the next arc to the right of the original line, create a construction line tangential to the base circle. Because the string is winding more tightly, the length of this line needs to be the original string line减它们之间的弧线长度。单击行类型“ =”;单击字符串线的尺寸；类型 ”-”;然后单击弧的尺寸。
Step 12
Repeat step 11 for the two additional arcs to the right of the original. If you are using about the diametric pitch for the arc length, then three arcs to the right will bring the end of the “string” almost in contact with the base circle; our imaginary string has been completely wound around the cylinder.
Step 13
放大到最后一个“字符串”的尾部，并从字符串的末端绘制一条小的垂直中点线，中点在基本圆圈上，因此现在在基本圆的末端直接下方有一个点细绳。因为我们无法将绳子缠绕到圆柱体中，所以这条线的第二点为我们在基本圆圈内的一点点为了完成齿轮齿。
Step 14
Open a new sketch on the same plane and draw a spline through the points from the uppermost (where the string is most unwound) to the lower right (where the string is tightly wound), plus the point inside the base circle created in step 13. You now have one side of the tooth drawn.
Step 15
Draw a construction line to represent the centerline of the tooth. For a 19-tooth gear, there are 19 teeth poking out and 19 spaces between the teeth, so we need the centerline of the tooth to be the whole circle (360 degrees) divided by 2 (the tooth and valley) divided by 2 (half the tooth) divided by 19 (the number of teeth). Dimension the angle as “=360/4/19”.
Step 16
Mirror the spline about the tooth centerline.
Step 17
To define the outside of the gear, create a circle around the pitch circle. Draw a radial line from base circle on the right hand side to the pitch circle and another from the pitch circle to the new circle (the outside). Make these two lines equal length, so the outside circle is the same radial length larger than the pitch circle as the base circle is smaller.
Step 18
Now we have all the lines that will define our gear. In another new sketch on the same plane, draw a concentric circle with extends to the inside end of the spline (just barely smaller than the base circle, allowing a small amount of clearance). Extrude this circle to the desired gear thickness.
Step 19
In a new sketch on the same plane, use “offset entities” and a dimension of “0.00” to copy the right hand spline into the new sketch. Repeat for the left hand spline.
Step 20
In the same sketch as above, use “offset entities” and a dimension of “0.00” to copy the circle from step 18. Then repeat for the outermost circle from step 17.
Step 21
In the same sketch, use “trim entities” -> “power trim” to cut off the parts of the spline which extend beyond the outside circle. (If you hide the body from step 18 and all the other sketches, the tooth will become visible.)
Step 22
将上面的草图从步骤18开始的圆圈挤出到相同的长度。单击挤出对话的“选定轮廓”框，然后单击牙齿区域内以突出显示牙齿区域。
Step 23
单击“线性图案” - >“圆形图案”，以提高圆形图案对话框。对于旋转，请单击步骤18的挤压圆的外部。以“ 19”输入实例数，然后选择“相等的间距”，然后单击牙齿以获取“功能和面部”以获取图案。
Congratulations; you have a gear!
特别感谢Steen Wintherfor developing the core of the method on which this tutorial is based.
