Author Topic: Looking for small motor shaft brake  (Read 1026 times)

0 Members and 1 Guest are viewing this topic.

Online KjeltTopic starter

  • Super Contributor
  • ***
  • Posts: 6586
  • Country: nl
Looking for small motor shaft brake
« on: January 14, 2020, 08:11:45 am »
In some steppermotors and servo's there is a brake built in. It is actually just like a car wheel brake it fits around the axis and clamps the axis when powered or better when unpowered, preventing the axis to move even after the power to the motor has been cut. Very handy and convenient when there is some static load attached that will move the axis.

Small motors do not seem to have those brakes, yes you can use a high ratio (1:50 or higher) gearbox , still the sideeffect is the slower response.
So I am looking for a small affordable (<$20) brake to fit a 6mm or 8mm axis, preferably for sale in standard production , so not a 2nd hand one off, from ebay.

Do they exist ?
Does anyone know where to buy them ?

Thanks.
 

Offline i_am_fubar

  • Regular Contributor
  • *
  • Posts: 53
  • Country: gb
Re: Looking for small motor shaft brake
« Reply #1 on: January 14, 2020, 05:38:54 pm »
Look for shaft electro magnetic clutches. Same mechanism.

http://www.chaintail.com/dry-single-clutch-brake-micro.htm
« Last Edit: January 14, 2020, 05:42:18 pm by i_am_fubar »
 
The following users thanked this post: Kjelt

Offline Gregg

  • Super Contributor
  • ***
  • Posts: 1156
  • Country: us
Re: Looking for small motor shaft brake
« Reply #2 on: January 15, 2020, 12:36:02 am »
It depends on the specific motor, of course, but it shouldn't be too hard to put a reduced current DC on opposing coils of a stepper motor to make a magnetic brake.
 
The following users thanked this post: Kjelt

Online IconicPCB

  • Super Contributor
  • ***
  • Posts: 1564
  • Country: au
Re: Looking for small motor shaft brake
« Reply #3 on: January 15, 2020, 06:06:11 am »
Depending on the "small" motor look into mobility scooter motor shaft brake.
 

Offline I wanted a rude username

  • Frequent Contributor
  • **
  • Posts: 662
  • Country: au
  • ... but this username is also acceptable.
Re: Looking for small motor shaft brake
« Reply #4 on: January 16, 2020, 12:16:07 am »
How much backlash can you tolerate?

If the purpose is safety rather than locking the shaft tightly in position, you could use a pawl similar to how automatic gearboxes park. It's reliable, reasonably strong, and the part tolerances are high.
 

Online KjeltTopic starter

  • Super Contributor
  • ***
  • Posts: 6586
  • Country: nl
Re: Looking for small motor shaft brake
« Reply #5 on: January 17, 2020, 02:43:38 pm »
The purpose is functionality that the axis does not start to move itself under the load after the power to the motor is off.
I like the  electro magnetic clutches website it also has permanent magnet brakes, those would do the job.
Now lets see where I can order them for testing.
Thanks people  :-+
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf