we were having some issues with a machine's swing. i don't fully understand how the swing mechanism, turn table, drive motor, and bearings work on an excavator. can someone help me to learn about this?
what machine?
Volvo EC 330
Do you want detail on how your specific machine works? Or do you want a general description of the typical swing system? If you want general description: The machine is attached to the undercarriage with a large bearing. Inner race is typically attached to the undercarriage, outer race attached to the excavator. The races are seperated by balls or rollers depending on bearing type. Gear teeth are typically cut into the inner race. A transmission (usually planetary) has a large output pinion that engages the gear teeth. When the transmission turns the pinion, the excavator rotates on the bearing. The swing transmission is attached to the excavator frame. The swing motor drives the transmission. The swing motor receives oil from a control valve and rotates. The gearing within the transmission will reduce the high speed, low torque output of the hydraulic motor into low speed, high torque required to swing the excavator. Usually, but not always, a mechanical brake is provided as a parking brake when the machine is not swinging. Usually, but not always, the motor is used to dynamically stop the machine. There are variations now, and in the past there were even more variations in excavator swing, but in general, that is how it works. What is your specific problem?
I would try to get a hold of the service manual for the particular machine. The manufacturer is the best source for that information for your machine. Please don't take this the wrong way, not trying to be a smart alec, but I know when I have to look up information in a book, I tend to remember it better later on.
we are experiencing a few problems. machine: Volvo EC 330BLC approximately 4500 hours. the dynamic brake doesn't seem to function fully. the machine takes a lot longer to stop swinging than that we normally expect it to. there seems to be some play in the gears. i can toggle the swing control back and forth and hear/feel some movement within before the machine without any swing action and i hear an audible clunk. to make this happening i am using an "inching" motion on the swing controls. sometimes the machine decides to start swinging on its own. it will go into a "convulsion" and twitch side to side for a few seconds.
It could be a signaling problem. Most swing drives have a swing brake. It's like a clutch pack that sits at the top of the swing motor. Springs hold it down when you are not asking it to rotate. When you move the lever (asking it to swing) hydraulic pressure overwhelms the force of the spings, thus releasing the brake. When you let go of the lever it releaves the hydraulic pressure on the brake, allowing it to begin braking. Your machine should not just start swinging on it's own. I'm not sure what to say about the "clunking" noise. I know that the gears can theoretically wear out but I would expect a well maintained machine should go about 10k hours before it needs to be repaired. Have you checked the level of grease that's in the sump? A lack of grease on the ring/pinion gears could allow it to make more noise than usual (and cause premature wear). My Cat has a small cover at the front/center of the house. Check your manual for details on this procedure.
swing problem mitsubishi ms120 I am also dealing with a swing problem. I just bought a 1987 mitsubishi ms120 excavator and the issue is that when you start up or slowing down the swing the machine shakes. feels like the swing brake is chattering. I changed the drive oil with new 80-140w thinking there was a wet clutch in the drive. on top of the hydraulic motor there is 2 adjusters and one is missing the cap. Are these adjusters that the previous owner messed with? Did I use the wrong oil in the drive?
Swing brakes are either on or off. They are not dynamic at all and are only used for parking the house in one spot. There could be many reasons for chatter of which the usual culprits are the cross over relief valves in the top of the swing motor. These are usually cartridge type valves that wear out over time. The springs get weak and you can adjust for that. Many times the pilot cones get a groove worn in them and they leak by causing the main poppet to not seat all the way. One of the give aways that you have this problem is the swing works well in one direction and poor in the other. I have also seen the piston and barrel assembly in the swing motor broken once or twice and that can cause the chatter that you feel and hear. Put a gauge in the circuit and you will see the needle chatter going both ways when this is the case. The other common reason for chatter is the grease is sagged down in the ring gear tub and the ring and pinion set is worn. Usually there is a plate under the boom foot joint with two bolts holding it down. Clean the area out before you remove the plate. Pull the plate and look inside. You will see the ring gear and a trough of grease underneath and in front of the teeth. You should be able to feel the grease on the teeth without cutting your finger on the tip of the tooth. The last common issue I've run into is the bearing itself is worn. Many times you will see metal being expelled from the bearing after you grease it. That doesn't always hold true though so I measure up and down play in the bearing with a dial indicator to be sure. Good Luck!
ms120 excavator swing motor where are the springs located? how can I adjust them? It is a Kawasaki mx80ca swing drive motor if that helps.
i know this thread is old but i wanted to get out what i have learned so far for others that might have the same problem. Volvo has a service bulletin on the EC330 for loose turn table motor bolts. these bolts become loose and can cause extra play in the swing. mine were not loose. we removed my motor and found that the motor drive gear is worn. this is the "clunking" heard when toggling the swing. anyone know if this gear can be turned over and reused or if it needs to be completely replaced?
Here are some pictures of our pinion. Is this worn enough to replace? OEM $3100 and have found an aftermarket for $2500 or $550 (in Korea). Any other thoughts?
Did you measure the back-lash before pulling the pinion gear?
Take a look at this link may be helpful http://www.youtube.com/watch?v=QC6s...DvjVQa1PpcFPYqq9hBiqVaOdqdl19moycvgdcOc6HaLQ=
uffex48@gmail if you would like more specific information re the slew system please dop me a line at the address noted
I have 330 blc as well, the brake doesn't seem to want to release and is prematurely engaging. What should I try and do to remedy this issue?
Good day Junior If all the other functions are OK it sounds you could have an issue with the time delay valve see attached.
I could really use some advice I have a ihi 35 nx and have slack in the swing motor I believe, I already have the swing motor out but cant move the pinion gear at all to tell if theres play in the shaft and I'm scared to break it apart from the gearbox portion of it until I find someone who might have a better understanding of how it works. My email is [email protected] and I could give you my phone number from there if you wanted to talk to me thanks in advance.
It sounds to me like you are talking about back lash between the pinion gear and ring gear. You should be able to look at the pinion gear and see if it is worn. A photo here and maybe some experienced eyes might provide a direction for you. You might be able to see the ring gear from under the carbody.