Gearbox Design Guide - Revision history

Juspar: /* Gears */

2009-06-27T02:46:14Z

Gears

Juspar: /* Personal Research */

2009-06-17T00:21:20Z

Personal Research

Juspar: /* Putting it Together */

2009-06-16T23:41:33Z

Putting it Together

Juspar: /* Putting it Together */

2009-06-16T23:40:49Z

Putting it Together

Juspar at 23:40, 16 June 2009

2009-06-16T23:40:16Z

Juspar: /* Gearbox design */

2009-06-16T23:37:28Z

Gearbox design

Juspar: /* Standard Gearbox Notation */

2009-06-16T23:35:00Z

Standard Gearbox Notation

Juspar: /* Standard Gearbox Notation */

2009-06-16T23:30:11Z

Standard Gearbox Notation

Juspar: /* Standard Gearbox Notation */

2009-06-16T23:29:15Z

Standard Gearbox Notation

Juspar: /* Standard Gearbox Notation */

2009-06-16T23:28:11Z

Standard Gearbox Notation

@@ Line 10: / Line 10: @@
 ! Gear Size !! Item       !! Metal cost !! Wax cost !! CC cost (student) !! CC cost (master)
 |-
-|0          ||Spacer      || 0          || 0        || 0                 || 0
+|1          ||Spacer      || 0          || 0        || 0                 || 0
 |-
 |3          ||Small Gear  || 2 Brass 	|| 2        || 1                 || 0.8 (batch of 10)

@@ Line 88: / Line 88: @@
 ==Personal Research==
 Link your personal build pages here.
-*[[User:Juspar/gearboxes|Gearboxes]].  Insert tab A in slot 2.
+*[[User:Juspar/gearboxes|Juspar's Gearboxes]]

@@ Line 66: / Line 66: @@
 ===Putting it Together===
-The need for gears to mesh, together with how they determine rotation, means that any output can be expressed as a product of a limited set of fractions. The earlier example is (3/5)*(3/5), expressing that going from 1A to 2B we mesh a 3-gear with a 5-gear (in that order), and the same from 2B to 3C. To build a gearbox with outputs in a desired range, you just need to find a sequence of fractions that multiply to give the right numbers. Much of the work has been done already, with a list of common [[gearbox ratios]] that may be useful.
+The need for gears to mesh, together with how they determine rotation, means that any output can be expressed as a product of a limited set of fractions. The earlier example is (3/5)*(3/5), expressing that going from 1A to 2B we mesh a 3-gear with a 5-gear (in that order), and the same from 2B to 3C. To build a gearbox with outputs in a desired range, you just need to find a sequence of fractions that multiply to give the right numbers. Much of the work has been done already, with a list of common [[Gearbox Ratios]] that may be useful.
 /3 and 4/4 just carry a given rotation rate from shaft to shaft, and are comparatively cheap since gears of size 3 and 4 are small gears. Many designed gearboxes contain chains of gears -3-3-3 or -4-4-4 carrying a given ratio to the required output shaft.

@@ Line 82: / Line 82: @@
 The relative cost of the various gear ratios ignores the small gears and assumes that a large gear costs 5 times as much as a medium gear. A combination like (3/5*5/6) that has a shared gear will be a bit cheaper. Note that every change in speed requires a medium or large gear.
-    * Cost of 1 - 3/5 and 5/3
+* Cost of 1 - 3/5 and 5/3
-    * Cost of 2 - 5/6 and 6/5
+* Cost of 2 - 5/6 and 6/5
-    * Cost of 6 - 4/7 and 7/4 (or 5/7 and 7/5)
+* Cost of 6 - 4/7 and 7/4 (or 5/7 and 7/5)
 ==Personal Research==
 Link your personal build pages here.
 *[[User:Juspar/gearboxes|Gearboxes]].  Insert tab A in slot 2.

← Older revision		Revision as of 23:40, 16 June 2009
Line 85:		Line 85:
	* Cost of 2 - 5/6 and 6/5		* Cost of 2 - 5/6 and 6/5
	* Cost of 6 - 4/7 and 7/4 (or 5/7 and 7/5)		* Cost of 6 - 4/7 and 7/4 (or 5/7 and 7/5)
		+
		+	==Personal Research==
		+	Link your personal build pages here.
		+	*[[User:Juspar/gearboxes\|Gearboxes]]. Insert tab A in slot 2.

← Older revision		Revision as of 23:37, 16 June 2009
Line 64:		Line 64:

	The same principle can be used many times in a row by using the 3 different layers available. A 3-gear on 1A can mesh with a 5-gear on 2B on the bottom layer, meaning that 2B rotates at 60%. Then we can put a 3-gear on the second layer of 2B, meshing with a 5-gear on the second layer of 3C (with a 1-spacer on the bottom layer). So 3C rotates at (3/5) of 2B, which is in turn (3/5) of shaft 1A. The final rotation rate of 3C is thus (3/5)*(3/5) = 36%.		The same principle can be used many times in a row by using the 3 different layers available. A 3-gear on 1A can mesh with a 5-gear on 2B on the bottom layer, meaning that 2B rotates at 60%. Then we can put a 3-gear on the second layer of 2B, meshing with a 5-gear on the second layer of 3C (with a 1-spacer on the bottom layer). So 3C rotates at (3/5) of 2B, which is in turn (3/5) of shaft 1A. The final rotation rate of 3C is thus (3/5)*(3/5) = 36%.
		+
		+	===Putting it Together===
		+	The need for gears to mesh, together with how they determine rotation, means that any output can be expressed as a product of a limited set of fractions. The earlier example is (3/5)*(3/5), expressing that going from 1A to 2B we mesh a 3-gear with a 5-gear (in that order), and the same from 2B to 3C. To build a gearbox with outputs in a desired range, you just need to find a sequence of fractions that multiply to give the right numbers. Much of the work has been done already, with a list of common [[gearbox ratios]] that may be useful.
		+
		+	3/3 and 4/4 just carry a given rotation rate from shaft to shaft, and are comparatively cheap since gears of size 3 and 4 are small gears. Many designed gearboxes contain chains of gears -3-3-3 or -4-4-4 carrying a given ratio to the required output shaft.
		+
		+	3/5 and 5/3 are the next cheapest, since size 5 is a medium gear.
		+
		+	5/6 and 6/5 come next in cost order, with both 5 and 6 being medium gears.
		+
		+	3/6 and 6/3 are shorthand, with an implicit 5-gear in the middle since 3-gears and 6-gears cannot mesh directly. Hence this ratio costs 2 mediums and a small.
		+
		+	4/7 and 7/4 are much more expensive: a 7-gear is a Large gear costing 120 iron and requiring the master casting box.
		+
		+	More expensive still are the shorthand ratios of 3/7, 7/3, 6/7 and 7/6, all of which have an implicit 5-gear in the middle to allow the others to mesh. Finally there is 6/4 which has an implicit 5 and 7 in the middle. Fortunately these ratios are almost never needed.
		+
		+	The relative cost of the various gear ratios ignores the small gears and assumes that a large gear costs 5 times as much as a medium gear. A combination like (3/5*5/6) that has a shared gear will be a bit cheaper. Note that every change in speed requires a medium or large gear.
		+
		+	* Cost of 1 - 3/5 and 5/3
		+	* Cost of 2 - 5/6 and 6/5
		+	* Cost of 6 - 4/7 and 7/4 (or 5/7 and 7/5)

@@ Line 42: / Line 42: @@
 * / meshes with.
-     example: 5/3 or (5/3) or 53 - a size 5 gear that meshes with a size 3 gear.
+     '''example''': 5/3 or (5/3) or 53 - a size 5 gear that meshes with a size 3 gear.
 * * shares a shaft
-     example: (5/3) * (7/4) - a size 5 gear meshing with a size 3 gear. On the same shaft
+     '''example:''' (5/3) * (7/4) - a size 5 gear meshing with a size 3 gear. On the same shaft
      as the size 3 gear is a size 7 gear, which meshes with a size 4 gear.
      example: (7/4) * (5/3) - the 7 still meshes with the 4, and the 5 with the three,
      but this time, the 4 and the 5 share a shaft. Note that this results in the same
-     output as the previous example - as long as all the same gears mesh, you can move it
+     output as the previous example - as long as all the same gears mesh, you can move
-     around in the chain without affecting the output speed.
+     it around in the chain without affecting the output speed.
 This notation gives a standardised way of representing the gearbox table. To get from the factored notation to the actual rotation rate, just multiply out the fractions. For example, the (5/3) * (7/4) combination above would give (5 * 7) / (3 * 4) = 35/12 = 2.91666666 (which, as a percentage, rounds to 292%)

@@ Line 40: / Line 40: @@
 ===Standard Gearbox Notation===
-* /: meshes with.
+*'/': meshes with.
      example: 5/3 or (5/3) or 53 - a size 5 gear that meshes with a size 3 gear.
-*: shares a shaft
+*'*': shares a shaft
      example: (5/3) * (7/4) - a size 5 gear meshing with a size 3 gear. On the same shaft as the size 3 gear is a size 7 gear, which meshes with a size 4 gear.