I have an old 642 with the inline engine and pump set-up like every other skid steer out there. I worked on a neighbors newer Bobcat, it has the engine sitting sideways with a big belt. Damn thing packed so tight, changing the muffler took 2 hours and just about every trick I have. So why did they change ? I see another maintanance part (the belt) and the tensioner, as problems.
first transverse mounted engine i saw was the 943, around '85 or so. when the 50 series machine came out, late 80's-early 90's, they went to current production on transverse mount engines with a drive belt. properly maintained drive belts last a long time, i've seen 20+ year old belts still hanging in there, i've seen improperly maintained belts tart to slip or break in 300 +/- hours. i'll take changing a broken drive belt over a broken ujoint anyday... :drinkup dry rot is the killer for any belt.
They wanted a short machine and needed more counterweight.
easy routine maintenance, filters & primer bulb are easy to get to, fuel solenoid has easy access. :drinkup
I spoke to the engineer who patented it (since retired) when I was a Bobcat salesman and he said they wanted to get more operating capacity and the other benefits you mention were side effects that they marketed the hell out of to downplay the difficulty of really having to do repairs beside daily service items.
Yeah but what about the other side of it? The thing I don't get is why they stick with a single chain case. I don't know the reasoning behind Bobcat and a transverse motor but assume a short machine with high ROC is possibly part of it or all of it. Maybe packaging due to single chaincase too? I wouldn't worry much about the drive belt, they don't seem to fail all that often. I don't know what OEMs use U joints anymore? Most use a drive plate/hub. They wear out too, but aren't terrible to replace. Just pull the motor. Most of them pull pretty quick. Bobcat guys have to pull theirs for plenty of stuff too.
The inline engines were a extreme pain to grease and/or replace the u-joints, no-one (But us) greased them, if the operator ignored the vibration from a failing u-joint and it blew up it would often bend the pump shaft or even the crankshaft. The belt solved all these problems, if belt maintenance (tension) was not done, the failure was minimal to repair! All you had to do was a new belt and/or tensioner. As you correctly say, Everyone else used a toothed coupler to avoid this, But Bobcat does use the easy to replace belt as a sales tool, And most folks (with no reason to know any better) fall for it. Now putting the fuel tank UNDER the engine??? I don't know how they get away with THAT one!!!!!
i like the single chain case because it gives the machine the v shaped smooth belly, which seems to be very strategic on the farm as far as being able to continue working in adverse conditions.
One thing we all have to consider here, the skid steer/CTL loader has evolved into a compact machine with a helluva lot of working power. Yeah, Bobcat machines have their "PITA" parts about them, as do other brands I have seen and worked on. The new Kubota SVL's, man they got hoses in places that I don't want to have to replace when they pop. My point, I don't think there's such a thing as a perfect skid/CTL for a mechanic, they're like zero tail swing excavators...10 lbs of stuff crammed into a 5 lb sack. JMHO.
My understanding behind the drive belt was you could achieve higher pump speed with less RPM's.
Mike, I believe you are correct. The engine pulley is much larger than the pump pulley. I thought it would be the opposite, but after research (google), I found that the engine could be running 500 rpms and the pump could be at 1000 rpms (Just an approximate example online). Direct connect would be one to one without gearing. Bobcat belt should mean lower engine rpms higher pump speed. Less fuel consumption.
Less noise too.
You would also be able to use a smaller displacement pump and achieve the required flow. Smaller pump reduces cost and weight.
contrary to popular belief, belts are actually very good! we are only talking 100 hp here i believe the 1000 hp forage harvesters are belt driven so... on the contrary... i don't know why they just don't install a variable displacement hydraulic pump right to the engine that way you can operate at low rpms and still get flow. i don't know... seems case may have employed this strategy before. it always confused me that in a bobcat you usually run wide open, and in an old case you just idle around... seems to me the bobcat strategy wasn't actually working out in real life.