Hydraulic motor

[Firewoodjoe]

The rotator motor on my forwarder bucket won't hold a seal anymore. I'm going to buy a new motor but I'd like to protect it from the sudden pressure it sometimes gets. Any ideas. We used to do a loop or something in the hydraulic hoses going to the motor in circle slasher saws so when they got stuck in wood it wouldn't blow the seal but I can't remember how we did them.

[Riwaka]

Depends on the complexity of the hydraulic rotator motor you might purchase. A number of options.

These rotators appear to built in relief valves, (spring or hydraulic brakes) and  swing dampers.
https://www.blackbruin.com/media/Black_Bruin_Rotators_EN_C.pdf

or
separate MMRV (motor mount relief valves)
Motor Mount Valves

or
2 x auxiliary relief valves - teed into the rotator motor pressure lines and joined back to a return to reservoir line etc.

[mike_belben]

You need a cushion valve.

[backwoodsdave]

Maybe a crossover relief like this https://www.surpluscenter.com/Brands/Prince-Mfg/3-4-NPT-30-GPM-1500-3000-PSI-Hydraulic-Cushion-Valve-9-4019-75-H.axd 
Not familiar with your machine but some old skidders  had a similar valve mounted in the boom for the grapple motor.

[Firewoodjoe]

Yes the Deere skidders have something like that. I thought we just ran another hydraulic hose from the supply to the return. Or is where that cushion valve would go. I think it's hard on the motor when I have large logs and I rotate it and stop. The logs have momentum and want to keep going. If that cushion valve will work I'll do that.

[Firewoodjoe]

It's a char-Lynn 101-1055-009

[Corley5]

Is there a relief built into the rotator?

[Firewoodjoe]

Corley no it does not. Ilog4u hooked me up with a motor that had a cushion block on it. I will try it tomorrow and I hope it fits and don't leak. That will be great! Thanks again ilog4u!!

[ilog4u2]

Your welcome,! Glad I could be helpful

[Firewoodjoe]

That block is the cushion valve I'm guessing and it works good so far. Acts like a clutch slipping in rather than just taking off fast. My old motor actually cracked the top plate that holds the seal in. Not sure if it was due to not having the block or not.

[mike_belben]

Yeah theres check valves between the A and B port wall that let the high pressure side spill over to the low pressure side.  Its sort of like a momentary motor spool to dissipate the overrun load but still have the hold capacity of a cylinder spool, minus the shock load.  Its exactly what you needed. Thumbsup