Importing and modifying a new mini excavator from China

[JamesTheNextDoor]

Thanks for posting, JAMES, and welcome to TBN.

Before the pinion gear broke, was there noticeable slop between it and the ring gear? How many hours on your mini?

Since your machine came with the boom-swing option, it sure seems that that circuit needs some cushioning, too. The boom-up/boom-down could use shock RVs, too, but I do not think the jerkiness in that circuit will break anything.

Thank you. I'm glad I found this forum. I didn't have anyone to discuss things with in my country, so it's nice to have this platform.

Before hitting 60 hours of operation, the pinion broke. Although backlash was a concern, most of the play stemmed from a damaged shaft key, consistently impacted by swing shocks.

In larger equipment, overcenter valves are often installed on booms. However, the 1-ton Kubota U10 only features an anti-cavitation valve(check valve).

Below is the table of relief valve settings for Kubota 008 and U10. Shock RVs pressure is quite low. Shock RVs also serve as overload valves, so when you actually use them, you may feel power is weaker than before and it's true.

However, it's not recommended to exert too much strain on the rotary actuator operated by gears anyway, so even if the power is weak, it doesn't seem to be a problem in practical use.

 

[JamesTheNextDoor]

What manual did you get that info from?

It's Workshop manual for kubota u10 and k008.

 

[jodieadair]

It's Workshop manual for kubota u10 and k008.

It's Workshop manual for kubota u10 and k008.

You should also join the Chinese excavator Facebook groups. They are not quite as technical but there are some very intelligent people there. facebook.com/groups/5508502585925303/ and
facebook.com/groups/1398622933920944/

 

[dfkrug]

I recommend that you also perform the attached tests for your safety.

Looks like a Kubota mini-X manual.

"Safety lock"? What is that?
On a 15-degree slope (27%), my house will rotate faster than those specs.

 

[dfkrug]

Before hitting 60 hours of operation, the pinion broke. Although backlash was a concern, most of the play stemmed from a damaged shaft key, consistently impacted by swing shocks.

In larger equipment, overcenter valves are often installed on booms. However, the 1-ton Kubota U10 only features an anti-cavitation valve(check valve).

Below is the table of relief valve settings for Kubota 008 and U10. Shock RVs pressure is quite low. Shock RVs also serve as overload valves, so when you actually use them, you may feel power is weaker than before and it's true.

Thanks for posting. I had no idea that the Kub had such a low cushion valve relief pressure. IDK if I want to go that low, but I may be on borrowed time with 150 hours on my Xiniu. It does seem that my machine is assembled better than many out there.

What are the "overcenter" valves you refer to, and how do they work?

 

[JamesTheNextDoor]

Thanks for posting. I had no idea that the Kub had such a low cushion valve relief pressure. IDK if I want to go that low, but I may be on borrowed time with 150 hours on my Xiniu. It does seem that my machine is assembled better than many out there.

What are the "overcenter" valves you refer to, and how do they work?

I don't think you need to follow these pressure values. It's more appropriate to find the suitable pressure through actual testing. I haven't even measured the pressure of the shock RVs.

Testing on a slope is to ensure that the cushion valve is properly set. Since this document is about Kubota equipment, you don't need to pay attention to the numbers. If the cushion valve pressure setting is too low, it may not hold and rotate freely at neutral valve position. For instance, during actual work, when carrying heavy objects or when affected by gravity on a slope, unintended results may occur when starting or stopping the swing.

You can think of the overcenter valve as a counterbalance with an external pilot line. When attached to the boom or travel motor, it prevents freewheeling.
I bought one. I’ll post it one day

Overcenter Valves are Key to Hydraulic Control | Armadillo Group

 

[dfkrug]

You can think of the overcenter valve as a counterbalance with an external pilot line. When attached to the boom or travel motor, it prevents freewheeling.
I bought one. I’ll post it one day

Interesting link. Thanks for posting. Different names for some of the same kinds of valves

Of even more concern should be the wheel motors. You should look into adding cross-port RVs (counter-balance valves, or wheel braking valves) to the wheel motors. This was done by request to the maker by local importer Jason. It helps a lot with keeping the mini-X from going downhill too fast. A Big Problem.

Note that ports already exist on the motors, but there is no info on how they are connected. Have you looked into this? Photo shows a wheel motor with attached valve block with 2 RVs.

 

[jodieadair]

Hey guys. It seems like we just talked about this. The pics are from a Facebook group user. He rented his machine out and the customer bent the motor mount. I feel bad for him and he mostly got criticism instead of help. I figured I would ask you smart guys about any possible straightening solutions. I believe the machine is still in the field. It is a 1.8 ton AGT 18.

 

[oldrustysteel]

Hey guys. It seems like we just talked about this. The pics are from a Facebook group user. He rented his machine out and the customer bent the motor mount. I feel bad for him and he mostly got criticism instead of help. I figured I would ask you smart guys about any possible straightening solutions. I believe the machine is still in the field. It is a 1.8 ton AGT 18.

I know what I would try first. I would spin the house around so the bucket is in front of the wheel motors.
I would extend the bucket out and push it into the ground as far as possible. An anchor point is what I am trying to achieve. attach a 4 ton come-along to the bucket and then around the outboard side of the wheel motor. Be sure the bucket is positioned so the cable is pulling forward and slightly toward the opposite wheel motor. Heat can be applied if necessary. I think with possible fine-tuning this may work.

 

[jodieadair]

I know what I would try first. I would spin the house around so the bucket is in front of the wheel motors.
I would extend the bucket out and push it into the ground as far as possible. An anchor point is what I am trying to achieve. attach a 4 ton come-along to the bucket and then around the outboard side of the wheel motor. Be sure the bucket is positioned so the cable is pulling forward and slightly toward the opposite wheel motor. Heat can be applied if necessary. I think with possible fine-tuning this may work.

Great suggestion, I'll pass it along.