Questions tagged [gears]

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1answer
28 views

Gear Ratio of a Stepped Planetary Gearset

I was looking into planetary gearsets, and came upon the concept of a stepped planetary gearset. In the image shown above, if my input was the blue sun gear, the output was the planet gear, and the ...
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3answers
29 views

What is a gearbox with switchable outputs called?

I need a mechanism with which one motor can drive one of two outputs. So only one output should be active at a time, but the mechanism should be able to switch between the outputs. What is a mechanism ...
2
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0answers
23 views

Can we reduce pitch of a lead screw to reduce backlash of the lead screw?

In gear design, the backlash is introduced in the design itself (not by tolerances of manufacturing) to allow free meshing of the gears. The backlash in the design can be minimized by reducing the ...
1
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1answer
19 views

Off the shelf solutions to problem of 2 way to 1 way rotation [closed]

Looking for commercial off the shelf solutions for 2 way rotation to 1 way rotation. For instance, at the input there is the possibility of clockwise and counterclockwise rotation. Regardless of the ...
12
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6answers
6k views

Why does a gear have extra holes?

In a gear you normally have a center hole for the shaft to be put into. Why do some gears have holes surrounding that center hole? Is it for weight reasons? Does it add stability? Is it so you can add ...
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0answers
43 views

Building a custom indirect actuator, any thoughts?

I’m trying to create a custom indirect actuator, that is controlled by a microcontroller, for a custom robotics project. I have selected motor and gears (according to Fd = W = T2*pi) so that the ...
2
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0answers
32 views

Volumetric oil pump efficiency goes up when viscosity goes down?? Strange behaviour

Riddle me this : we are driving an external gear pump (this kind) at a fixed RPM. At start, when the oil temperature is low (and viscosity high), the volumetric flow is much less than when the oil ...
2
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0answers
35 views

Optimum spoke shape for wheels made of solid material

Currently I am designing a bicycle sprocket to be laser-cut out of 3mm steel. Steel is heavy, so I want to make some lightening cut-outs, and I want to optimize the shape of the cutouts. I will ...
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0answers
35 views

Use of pulleys in gearboxes

I'm designing a simple gearbox with some fairly strict space constraints. I was wondering if having a belt pulley inside of a custom gearbox is a serious issue for the belt. Would it get worn down ...
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2answers
810 views

Does a gear retain its mechanical advantage in a 1 2 1 ratio?

For example if the first gear has 32 teeth and the second 64, if the third also has 32 teeth would the output of the third retain the mechanical advantage created by the first 32 tooth gear powering ...
2
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0answers
25 views

I'm looking for the simplest way to increase rotational speed from 120 to 5,000 rpm for a light duty device

I'm currently designing a device and want to increase speed from 120 to 5,000 rpm. Device is lightweight, hand operated, free spinning, low torque in/out. Picture a cheap fertilizer spreader from Home ...
1
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1answer
43 views

Precision of a steeper motor and gears vs multiple motors

We are a student team trying to design a low cost CNC plasma cutting machine. The CNC will be a table with two rails and a bridge moving on them in which the head of the plasma torch will be. Now we ...
3
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1answer
26 views

Friction versus ratcheting pawl

We are working to design a lock mechanism and need to hold a square plunger out of a hole for extended periods of time (potentially years). The square plunger is under pressure from springs to return ...
1
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1answer
52 views

Determining the torque needed for a servo motor

I'm looking for a bit of clarity on a design I have in mind. Please bear with me as I have no background in physics, engineering and this is part of my first real DIY project, so the knowledge base ...
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0answers
36 views

How to calculate gear tooth position while assembling a planet gear?

A stepped planet series gear looks like this: Given that: Planet gears are evenly distributed (with 120°) Sun-gear-1 and Sun-gear-2 is lined up. Sun gear tooth counts: nS1, nS2 Planet gear tooth ...
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4answers
46 views

Does the torque on gear varies with different gear arrangements?

Suppose that there is a gearbox with gear ratio 3000:3. The gear with 3000 rpm will have a smaller torque than the 3 rpm gear. My question is that will for different gear arrangement(i.e planetary ...
3
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0answers
44 views

Worm Drive Clutching Mechanism

Problem Description I have a project where I will need to be able to engage and disengage a worm drive (actually two of them). The worm drives are quite small. The worm gear is 49.2mm in diameter ...
1
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1answer
24 views

Delivering RPM from a fixed wheel to a moving wheel

I have spent the past few days thinking about a good way to get power/RPM from a fixed wheel delivered to a wheel that is able to move in a 2D plane relative to the fixed wheel. I am not too good at ...
1
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0answers
41 views

Can we calculate the torque acting on the last gear determine teeth of the gears of the gear train in the below addressed manner?

The specifications of the generator is as follows: Efficiency- 70% Rated Torque- 0.56Nm Rated current- 14.3A Voltage- 24V Rotor shaft dimension- 1cm(diameter) The ...
2
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3answers
102 views

Feasability of glass gears?

I recently saw a video where a glassblower was making something, and one of the first steps was to push the wad of molten glass down into a shaper with a number of vertical spikes, such that the ...
1
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1answer
62 views

Adding the effects of two rods to move a single rod

I have to deal with a situation where I have two parallel and completely independent rods whose motion is dependent only on external inputs, and I want to add up the lengths traveled by each rod. My ...
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1answer
22 views

Gear mechanism for automatic gate

I have a sliding gate installed on my compound wall. I want to control the gate opening/closing with a motor. I have the electronic circuitry to control motor start/stop. I m thinking about attaching ...
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0answers
20 views

How to fix a shaft in position, vertically [duplicate]

I am doing a project where I have to mount a gear shaft with two bearings on either end (deep groove ball bearings) but I am worried that they may fall through the bearings during operation as the ...
1
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2answers
55 views

Vertical gear shaft support

I have a question regarding how are the vertical forces on a spur gear shaft are supported. I am currently doing my undergraduate (in final year) and have only dealt with gearboxes where the shafts ...
1
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1answer
39 views

Geometric constraints on Planetary Gears

I would like to design a single stage planetary gearbox using standard gears. There appears to be three primary conditions to ensure the geometry of the gears will fit - correct center distance, ...
1
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2answers
88 views

Engage and disengage DC motor from free-spinning reel

So i want to have a reel (~4cm diameter) that will pull a ~80cm string with a torque of ~8kg-cm (edit: thanks for the clarification). To pull I want to use a gear motor. E.g. 12V DC motor like this: ...
1
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3answers
49 views

Key fitting - Shafts and Gears

I am designing a gearbox and wanted to know whether the key on the shaft and gear must fit exactly with the bore in the gear and keyway in the shaft. Ex. If there is a key that is 3x3 mm, and does the ...
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2answers
53 views

Optimal gear combination with the same ratio

Summary: In a gear train, with given target ratio and configuration (eg. number of gears and how many compound gear steps are involved), what are the considerations when trying to select the optimal ...
2
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2answers
29 views

How are planetary gearboxes held together?

I see that the housings of most planetary gearboxes consist of 3 parts: a front cap, a ring gear and a rear cap. Here's a common design: In designs similar to this, the rear cap and the ring gear are ...
2
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1answer
50 views

Is there a way to convert a short throw in one direction into a long throw in two directions

I have a motor that I have created a simple adapter for; this lets us attach any parts we might design to solve the final problem: I would like to convert the motors motion to oscillating motion in ...
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2answers
59 views

What is the easiest way to regulate the speed of a falling object?

I want to design a system that allows a 1kg metal brick to fall under gravity at variable speeds. The brick initial position is 20cm above a flat table. I want to have control on the duration (to ...
1
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1answer
42 views

Calculating force transferred from pinion gear to rack

I am really challenged as I need to fit a bunch of motors in a 6" box acting as linear actuators. I was looking for linear actuators (most I found were brushed DC) at first but the ones I found that ...
14
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3answers
6k views

How do bike wheels keep turning when the rider stops pedalling?

I am very confused with something regarding bikes... How is it that a bike wheel continues to spin (either from momentum or from going downhill) when the rider is not pedalling, without also spinning ...
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1answer
27 views

Increasing rotation via simple gears

Complete amateur here with a product idea and a need to find out whether it can work in theory. I need to push a lever vertically down through 90 degrees and have a lateral arm swing horizontally ...
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2answers
39 views

Calculating and Designing a Ring Gear for LEGO

I'm working on 3d printing a planetary gear for LEGO. I've got a constrained set of planetary + sun gears and was looking into designing a custom ring gear. I've read a little bit into the design of ...
2
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1answer
39 views

How to I determine the dimentions for a worm gear?

I have a worm gear set with no drawings. I need to model them. The only things I know are 1) The Gear ratio is 30, and the worm gear only has one thread. It is a single start as opposed to a multi ...
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2answers
41 views

Does the rack for a rack and pinion often have or need to have the involute profile?

I am looking at designing a rack and pinion system that will be laser cut out of some plastic. While the cad system that I am using has a spur gear generator, I was looking at the design of the rack ...
2
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2answers
104 views

Gear train using two inputs and one output. Understanding six link epicyclic gear topology - Interpreting displacement graphs

I'm interested in printing a working two degree of freedom planetary gear set. I searched around and found a paper from University of Maryland in 1988 (source). I am having difficulty translating the ...
2
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4answers
159 views

How can a clutch engage gradually without wearing away very quickly?

Here's an animation of a gearbox and clutch from Wikipedia. I learned to drive recently, and was surprised at how the clutch worked, engaging gradually as I moved the pedal by fractions of a ...
0
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1answer
74 views

Determine if car is moving forward or backward

I would like to know if there is someway i can figure out if the car wheel is rotating in clockwise or anticlock wise direction. Im working on a project which determines if car rolled back on a hill ...
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0answers
65 views

Wobbling DC motor head

I have used 250 watt DC motor, for DIY electric potters wheel. Motor rated with RPM 3300 and geared reduction to 330 RPM. The issue I am facing is wobbling of the motor head. This issue is with the ...
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0answers
22 views

Bevel gear friction and inertia calculation

I want to calculate the friction and inertia between 2 bevel gears with straight teeth. I know how to calculate those parameters between regular gears with straight teeth. Is there any difference for ...
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0answers
24 views

Efficiency of harmonic gear drives

Does anyone have application experience with harmonic gear drive efficiencies as opposed to planetary or parallel axis reduction systems? I'm looking into drives with about a 25:1 reduction, and it ...
1
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1answer
29 views

Inertia and friction between gears

I have a question regarding inertia and friction between gears. I have a gear which is connected to the rod at one end and an electric motor which is connected to the other end. I know the torque of ...
3
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1answer
48 views

Gear profiles (involute and root) generated by power skiving

@Involutius contributed an article on the equations that describe the root profile of gears which are cut by a trapezoidal-profiled hobbing tool. From that article, I was able to do a slightly ...
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2answers
115 views

Calculating the torque required to move and hold an arm parallel to the floor

I'm a computer scientist doing a dissertation in robotics and I'm designing a mechanical arm that mirrors a humans, as such I am wanting to pivot the entire arm from a "shoulder" using a stepper motor ...
2
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1answer
59 views

Torque between concentric gears

First time asking question here. I'm not a mechanical engineer! I have a simple question that I can't explain the answer to it. I have a double gear (2 concentric gears with different radius) and I ...
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0answers
32 views

I need a mechanism/method to control a shaft that can rotate at different speeds. (faster clockwise and slower anti-clockwise)

I need to develop a mechanism - Where in I have a shaft that needs to rotate at different speeds. Lets say at a higher RPM clockwise and a lower RPM anti-clockwise. This shaft is attached to my ...
1
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1answer
84 views

Is there a way to auto-reverse cassette tape with gears only?

From what I read, tape decks auto-reverse by having a sensor keep track of an encoder. When the take up pulley stops turning, the logic board reverses the direction of the motor (and does some other ...
6
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3answers
863 views

How Much Efficiency is Lost in a Gear Train

I want to get a rough estimate for the transmission efficiency of two different gear trains. One is a one-stage gear train with 11.67:1 ratio (140/12 teeth) and the other is a compound two-stage gear ...

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