|
|
|
![]() |
|
|||||||
|
||||||||
![]() |
|
|
Thread Tools |
Rating:
|
Display Modes |
|
|
|
#1
|
|||
|
|||
|
Re: pic: Low Profile Gearbox Front View
How is this mounted to tubing? It looks like it's only using the bearing block bolts to hold the gearbox on.
Also, slight tidbit - the ability to use multiple pinion sizes is a design and feature of WCP gearboxes, not the VEX ones. The DS and SS are made by WCP. VEX and WCP are resellers of each other's products. Just clearing that up so that credit is given where credit is due. |
|
#2
|
||||
|
||||
|
Re: pic: Low Profile Gearbox Front View
What is the weight?
How thick are the side plates? Are you using a custom or COTS shifting shaft? If so, which one? How is this mounted? Are the cims acting as nuts for the standoffs? If so, consider changing that to just nuts or pemnuts. How are the shafts constrained? Are they hex turned to round? That's all for now. I can't tell much from this view, but it looks pretty good. |
|
#3
|
|||
|
|||
|
Re: pic: Low Profile Gearbox Front View
Quote:
It is this one: http://www.vexrobotics.com/217-3635.html The shafts are 3/8" hex shaft turned to 3/8" round but I might possibly use 1/2" hex and turn that to 3/8" because there isn't much material to constrain the shaft against the bearing with the 3/8" hex shaft. I am in fact using the cims as nuts but I am curious to know why there is a problem with this. Would it be a structural issue? |
|
#4
|
|||||
|
|||||
|
Re: pic: Low Profile Gearbox Front View
Not so much a structural issue as a maintenance one. It's a pain to have to remove the motors to disassemble the gearbox or to disassemble the gearbox to remove a motor.
|
|
#5
|
|||
|
|||
|
Re: pic: Low Profile Gearbox Front View
What do you guys think of the gear ratios? Are they appropriate gear ratios for a 3 cim gearbox?
And also, Sanddrag, I hadn't noticed that the pulleys would hit the standoffs but I just raised the location of the standoffs to give enough clearance for the pulleys. Thanks for noticing that! |
|
#6
|
|||
|
|||
|
Re: pic: Low Profile Gearbox Front View
Yeah, we totally missed it through multiple design reviews on one of our gearboxes one year. Didn't catch it until assembly. We vowed to never repeat that oversight.
|
|
#7
|
||||
|
||||
|
Re: pic: Low Profile Gearbox Front View
Quote:
3/8" hex turned to 3/8" will work fine. Look at the new Thunderhex usage examples to see how small a shoulder you can use. Bearings are very high precision, and you will have about a 1/32" shoulder on six points to constrain it. As stated above, it's a maintenance issue. If you lose a CIM somehow, then having to take off the gearbox and reassemble it is a no-no. |
|
#8
|
||||
|
||||
|
Re: pic: Low Profile Gearbox Front View
Under what conditions would one "lose a CIM"? In 10 seasons I have yet to experience a bad CIM or see one in person.
|
|
#9
|
||||
|
||||
|
Re: pic: Low Profile Gearbox Front View
It's actually really difficult to just pull a CIM out of a gearbox without taking it apart. If you're using a 12 or 11 tooth pinion, the retaining ring on the CIM catches on the gear that the CIM pinion mates to. If you're using a 14 tooth gear, the pinion won't fit through the .755" hole for the CIM boss.
Also, if you did want to remove the CIM without disassembling the gearbox, I'd be willing to bet that the gearbox wouldn't just fall apart if one (or even all three) of the upper standoffs were removed. If you wanted to disassemble a gearbox without removing a CIM, you'll have to remove one of the mounting bolts from each CIM. From experience, the CIMs don't fall out of the gearbox when this happens. They can't go anywhere because the one remaining bolt hold the CIM boss in a tightly fitting hole. It looks like a solid design, and the gear ratios sound good too. |
|
#10
|
||||
|
||||
|
Re: pic: Low Profile Gearbox Front View
Quote:
Quote:
|
|
#11
|
||||
|
||||
|
Re: pic: Low Profile Gearbox Front View
It always happens to us. We can usually get it far enough out to wiggle it around the other gear, though.
|
|
#12
|
|||
|
|||
|
Re: pic: Low Profile Gearbox Front View
Quote:
One thing that does concern me though is the ease of changing belts if they snap. |
|
#13
|
||||
|
||||
|
Re: pic: Low Profile Gearbox Front View
Quote:
But seriously, is it that hard to just add one more non-cim standoff? Two standoffs can hold your box together when swapping cims. In that situation, having through bolts to your cims is wise because it becomes easy to remove and add cims. Last edited by asid61 : 22-12-2014 at 00:38. |
|
#14
|
|||
|
|||
|
Re: pic: Low Profile Gearbox Front View
What precautions are you going to take to ensure that your 6 CIM drive doesn't completely die when it goes under 7 volts of battery during a pushing match or high acceleration and the PWMs cut out due to the new control system?
|
|
#15
|
|||
|
|||
|
Re: pic: Low Profile Gearbox Front View
Quote:
Still waiting on 234's full report to make a call on it. |
![]() |
| Thread Tools | |
| Display Modes | Rate This Thread |
|
|