i am building a mini dozer. i have a hydraulic motor for each side of track for propulsion...the motors where off a zero degree mower....this is all i have ...i am planning to utilize a cylinder to raise front blade also...know heres the question.i have 14 horse kohler engine can i get like a 2 stage pump for a log splitter with a 3 spool valve two operate the two independent drive motors and cylinder..or would i have to get different kind of pump with more horsepower..just trying to use engine i have..if nothing else a 2 spool for the motors..any and all help apprecaited thanks
mini dozer hydraulic question?
- Thread starter mostlyred
- Start date
- Views: 13645
J_J
Super Star Member
- Joined
- Sep 6, 2003
- Messages
- 18,952
- Location
- JACKSONVILLE, FL
- Tractor
- Power-Trac 1445, KUBOTA B-9200HST
I would not recommend a log splitter pump. You still have to match the HP and the pump, and the pressure should match the pressure of the hyd motors, and supply the GPM's as necessary .
For that 14 HP engine, a pump size of .4 cu in, at 3000 psi, and 7 GPM's is your limit.
So then, if you supply 7 GPM to both motors, what speed will you achieve?
{ What you need is a variable speed pump, that will let you operate two pumps and two motors, with each having it own control}
Ignore the last paragraph. Correction below.
For that 14 HP engine, a pump size of .4 cu in, at 3000 psi, and 7 GPM's is your limit.
So then, if you supply 7 GPM to both motors, what speed will you achieve?
{ What you need is a variable speed pump, that will let you operate two pumps and two motors, with each having it own control}
Ignore the last paragraph. Correction below.
Last edited:
AKKAMAAN
Veteran Member
J_J
Super Star Member
- Joined
- Sep 6, 2003
- Messages
- 18,952
- Location
- JACKSONVILLE, FL
- Tractor
- Power-Trac 1445, KUBOTA B-9200HST
Yep, slight correction. One engine driving two variable speed pumps, each operating a hyd motor.
AKKAMAAN
Veteran Member
it seems likethe more i try to understand the more complicated it is to me...i dont mind buying pumps .valves etc,,,but dont want to buy something that will not serve what it needs to do...can you give me some example as to what you mean by varable speed pump??how many horsepower would it take to run two pumps?/idid hook up one motor to splitter to see what rpm s i could get about 70....i do know different pumps ,pressure .gpm is gpoing to change that...open for all suggestions....i just like building and trying new things...i just dont know squat about hydraulics....and it shows,c ant hide it:
J_J
Super Star Member
- Joined
- Sep 6, 2003
- Messages
- 18,952
- Location
- JACKSONVILLE, FL
- Tractor
- Power-Trac 1445, KUBOTA B-9200HST
For example, my Dixie Chopper has a 25 HP Kohler, driving two pumps, and has hyd wheel motors. Each pump is a variable speed pump in that as you push or pull the lever for the pump, the machine will move forward or backward. You need two pumps because each one provides the fluid to run the hyd motors, one on each rear wheel at a certain speed. In a turn, you push one lever further than the other and you will turn in the direction of the slowest wheel motor. With the variable speed, you can creep along or race at full speed, which is usually about 6 to 10 MPH.
You say you don't know squat about hydraulics, but you need to understand the operation and limitations of a hyd system. I would be in the dark also if I just picked up several pieces of hyd hardware, and tried to jumble up something. You might just ruin the pumps and motors by now knowing. Hydraulics things have to match up to some degree. You learn by doing, reading, and more doing.
On one of my smaller Choppers, there is a belt from the engine that is turning two pumps, and the fluid not used is sent back to reservoir. As soon as I push on a lever, the pumps start pushing fluid to the wheel motors, and if you do this equal to both levers, you will travel in a straight line. If you slow one side, the machine will turn in that direction.
The reason they refer to them as zero turn, is that if you push one lever forward, and pull the other lever backward, you will turn the machine on a dime, so to speak.
You say you don't know squat about hydraulics, but you need to understand the operation and limitations of a hyd system. I would be in the dark also if I just picked up several pieces of hyd hardware, and tried to jumble up something. You might just ruin the pumps and motors by now knowing. Hydraulics things have to match up to some degree. You learn by doing, reading, and more doing.
On one of my smaller Choppers, there is a belt from the engine that is turning two pumps, and the fluid not used is sent back to reservoir. As soon as I push on a lever, the pumps start pushing fluid to the wheel motors, and if you do this equal to both levers, you will travel in a straight line. If you slow one side, the machine will turn in that direction.
The reason they refer to them as zero turn, is that if you push one lever forward, and pull the other lever backward, you will turn the machine on a dime, so to speak.
AKKAMAAN
Veteran Member
it seems likethe more i try to understand the more complicated it is to me...i dont mind buying pumps .valves etc,,,but dont want to buy something that will not serve what it needs to do...can you give me some example as to what you mean by varable speed pump??how many horsepower would it take to run two pumps?/idid hook up one motor to splitter to see what rpm s i could get about 70....i do know different pumps ,pressure .gpm is gpoing to change that...open for all suggestions....i just like building and trying new things...i just dont know squat about hydraulics....and it shows,c ant hide it:
A fixed displacement pump can NOT change the displace volume per revolution . Dispalced volume, or flow, can only be changed by the rpm on the pump shaft.....hydraulic pumps ususally need some rpms to create enough pressure to compensate for the internal leakage in the pump and the control valve....
A variable displacement pump, usually an axial piston pump, can have the displacedvolume change while running at a fixed rpm....all from zero gpm to some max gpm.....that change in displacement is either manually controlled by the operator, like any ride mower, or controlled via an electro hydraulic servo system, like on heavy equipment (excavators for example)....
I personally think that your 14hp Kohler will have full duty just to stay even with all the power losses in the system.....Hydrostatic systems are simple on a mower but when you want to individually control two tracks with 14hp....it seems little tough to me....
wvpolekat
Platinum Member
Controlling two tracks is no different than controlling 2 wheels. One motor, two pumps, two motors. Doesn't matter if those motors are driving wheels or tracks, the system will have the same losses and such to deal with.
