Hydraulic Controls - Table of Contents

For context, see: Bulldozer Modules and Bulldozer Design.

Download CAD

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Hydraulics

1. Requirements
2. Control Basics
3. Control Valve
4. Selector Valve
5. Parallel and Series Operation in One
6. Benchtop Prototype

Note: this shows ⅓ of the bulldozer track drive.

Benchtop Prototype

• Power Cube -
• Tabletop Model with real connnection
• Green is quick connect
• Red is 1” quick stiff coupler
• Document All Valves and Motors

RHS Parallel

• Begin Assembly - [2] Motor Panels for RHS parallel
• Wire V1 and V2 in and out ports
• Test without moving valve
• Add S2
• Test
• Add M1 and M2, Quick Connect

to R1 (RHS Rotor)

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PC

V1

V2

S2

S1

header

motor panel

header

Top View

Right Side

M3

M1

M2

M4

rotor RHS

motor panel

M3

M1

M2

M4

Valve Documentation

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Top View

Direction of Rotation of Motor

Bidirectional Motor Control Valve

View from back of motor

Bidirectional Motor Control Valve

Top View

B

A

B is power on Right Hand Drive Motor

• Note - this was reversed on right hand drive

Direction of Rotation of Motor

View from back of motor

B

A

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Right

Drive

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Benchtop Prototype

After Initial Build Afternoon

• Issues arose when we did not comprehend directonality on the Motor Panels
• Solution: trace a specific circuit to determinte the connection

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PC

V1

V2

S2

S1

Top View

rotor RHS

M3

M4

Top View

Benchtop Prototype

Forward Drive Fluid Flow in both Parallel

and Series Operation (Blue is Series)

V1

V2

B

B

“B”

Lever down on selector valve means port “B” is power port

M4

• Issues arose when we did not comprehend directonality on the Motor Panels
• Solution: trace a specific circuit to determine the connection
• Orientation: top of page is facing forward on Benchtop Prototype, laid out just as in Cab so forward motion means forward

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• With S1 and S2 lever in down position, rRHS of valves is active
• LHS of valves is closed, thus effectively closing the entiring blue circuit

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Benchtop Prototype

Forward Drive Fluid Flow in both Parallel

and Series Operation (Blue is Series)

• Issues arose when we did not comprehend directonality on the Motor Panels
• Solution: trace a specific circuit to determine the connection
• Orientation: top of page is facing forward on Benchtop Prototype, laid out just as in Cab so forward motion means forward

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• With S1 and S2 lever in down position, rRHS of valves is active
• LHS of valves is closed, thus effectively closing the entiring blue circuit

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M3

M4

V1

V2

B

B

Lever down on selector valve means port “B” is power port

“B”

V1

V2

B

B

Lever down on selector valve means port “B” is power port

“B”

• Pink is series
• With S1 and S2 lever down, RHS of S1 and S2 is active (parallel)
• With S1 and S2 lever up, LHS of S1 and S2 is active (series)
• When either RHS or LHS of S1 and S2 is active, the opposite side effectively does not exist - so only parallel or series configuartion is active at one time
• Disadvantage: series configuration does not allow steering

Product

Open Source Circuit for Converting from Series to Parallel Drive on a Tractor

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this side of valve is unnecessary

need a closed center valve

MP1

Product

revA ver0.2

Open Source Circuit for Converting from Series to Parallel Drive on a Tractor

p

s

sp

M

F

• Slide 8 explains the pre-optimized version
• We can connect V to MP1

MP1

A

V1

B

B

V2

In series, we control machine with V1

This side is blocked because V2 is a motor valve and freeflows to port B on S1 - which is closed in series mode.

B

A

Is it ok if freeflow happens through A and B of V2 in series mode?

No freeflow occurs because port B of S1 is blocked.

Product

rev 15.8.23

Open Source Circuit for Converting from Series to Parallel Drive on a Tractor, not bidirectional. Red is series. Purple is reverse in series. V2 is blocked in series, all control goes through V1.

p

s

sp

M

F

• In series, we connect MP2 to MP3
• MP2 TO S1 is closed in parallel

MP1

A

V1

B

B

V2

B

A

MP2

MP3

This is blocked at port B of S1

after freeflowing through V2

A

Production Drawing

rev 15.8.23

Open Source Circuit for Converting from Series to Parallel Drive on a Tractor, not bidirectional.

9/17/15 review: see text at video

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p

s

M

F

• In series, we connect MP2 to MP3
• MP2 TO S1 is closed in parallel

MP1

V1

B

B

V2

B

A

MP2

MP3

Product

Open Source Circuit for Converting from Series to Parallel Drive on a Tractor

Product

revA ver0.2

Open Source Circuit for Converting from Series to Parallel Drive on a Tractor

M

F

behind head on left side

V1

V2

Product rev B

Open Source Circuit for Partial Conversion

from Series to Parallel Drive on a Tractor.

Point: series or parallel control on left or right side. Allows full bidirectional control.

p s

p s

s p

Product rev C

Open Source Circuit for Partial Conversion from Series to Parallel Drive on a Tractor

PC

will fluid free flow between ports A and B without restriction?

Product rev C

Open Source Circuit for Partial Conversion from Series to Parallel Drive on a Tractor

This is bidirectional in both series and parallel.

PC

p s

p s

Product rev C

Open Source Circuit for Partial Conversion from Series to Parallel Drive on a Tractor

PC

Parallel + Series Detail

Right Hand Drive Motor

Power

Cube

14 GPM

• This is looking from the top of the motor. To spin the same direction, bungs on opposite motors must be reversed like this:

(If motors are identical and on opposite sides of MicroTrac, they will spin in opposite directions.)

port A

port B

pulling activates

port A or B? And is this uniform for different manufacturers?

Note: for intuitive use, direction of valve will correstond to forward and backward. Thus, it is important to understand which port is activated in which direction, and which motor port corrosponds to which direction of motion. Further, high speed selection levers should be pushed forward to activate high speed series operation.

Connection Convention Notes:

• Keep orientation of valves uniform: relation of lever, A, and B ports must be consistent (correct rotation direction) and understood (forward and reverse must be intuitive)
• For motors, opposite sides means that bungs have to be reversed
• Set orientation as forward lever (depending on mounting orientation) = port A is pressure on valve is male = port A on motor receives fluid for correction direction of motion is female
• This has to be determined with the actual components; note that this may not be uniform between manufacturers, and open source standards are critical here
• For any 2 connections on opposite sides, whether Parallel or Series - Pressure ports must be reversed in orientation because of mirror symmetry
• Front is connected to front on opposite sides in series
• Front is connected to back in parallel

Forward direction noted by location of Cab

reversed bungs (note crossing)

2 levers are connected so that they are actuated at the same time

P

P

• In series operation, each motor receives 14 GPM

V1

S1

S2

V2

pc

Controls General Requirements

Requirements

• To create a true construction set for heavy equipment, the controls have to be:
• Flexible - capable of controlling various functions and implements
• Multiscale - applicable anywhere from 1 to 100 hp per actuator by both allowing a range of fluid flow (0-40 gpm)
• Stackable - multiple modules may be stacked for higher throughput
• Modular - quick-coupled interchangeable for modification and different use
• Open Source - design explanations allow for time-binding (general semantics) on design effort
• Multispeed - achieves multiple speeds via hydraulic circuit, not gears
• Automatable - designed for 60’ sylvopasture
• Practically speaking:
• To optimize drive system, controls allow for Parallel or Series circuit operation in one.
• This allows for multiple speeds
• Slow mode uses 1-6 Power Cubes with 6 motors in parallel
• Fast mode uses 2 Power Cubes per motor in a parallel configuration

Hydraulics Connection Requirements:

Quick Couple Everything!

• Clean interface to and from Power Cubes - nothing but ½” hose to and from connection panel
• Front implement connections travel along arms from pivot (point of minimum motion)
• All outlets point back behind driver, to go either to front (loader & implements), or to back (back loader, PTO, and implements)
• Allowance for loader arms and curl cylinders, 45 GPM and 28 gpm
• Selectability between front and back loader, which are identical
• Allowance for 2 hydraulic cylinder takeoffs, 14 GPM
• Allowance for 2 hydraulic motor takeoffs, 14 GPM
• Allowance for 2 hydraulic motor takeoffs, 28 GPM
• Allowance for 2 hydraulic cylinder takeoffs, 28 GPM
• All take-offs are compensated for pressure (in series connection - pressure through takeoff does not rob other components of flow, only pressure)
• Valves are able to be modified by having multiple 14 GPM quick-couplers
• All valves are coupled via quick couplers in the rapid prototyping stage

connection panel

Hydraulics Connection Strategy - Overall

Connection Panel

just check valve, no combining of flows

45 GPM wheel motor valve

½”

14 GPM cylinder valve

14 GPM motor

each line represents ½” hose of fluid from Power Cube

½” hoses until this point

14 GPM cylinder valve

14 GPM motor valve

45 GPM selector valve - wheels

28 GPM motor (PTO)

28 GPM motor

Wheel Connection Panel

28 GPM cylinder

• How to do this so it’s reconfigurable?
• Complete reconfigurability occurs when each connection is kept to ½”, 14 GPM - and multiple hoses are run to each larger component
• Red box - these can be ignored and additional valves can be inserted as needed for reconfiguring functions
• 45 GPM are the largest components, requiring 3 hoses
• Small valves - 14 GPM single - are used
• Keeping each quick-coupled connection to nominal 27 hp makes sense
• For double power, any component will have one or multiple connections
• Wheel drive system is hard wired, as this part stays the same (while allowing for single or multiple MicroTracs)

Header (combines flows)

From here on, everything is 1”

45 GPM selector valve - wheels

45 GPM wheel motor valve

45 GPM selector valve - wheels

Hydraulic Control Concept Simplified

Individual Feeds

Combining Header

Wheel Circuit

• Wheel circuit feeds 84 GPM max, and requires all the tractor power
• Any other circuits need to be fed prior to this in series with this, while the circuits are separate
• If connecting to this circuit, can tap 84 GPM only, or unknown amount only - so not a practical point of connection

• Individual feeds are ONLY a place to connect Power Cube Feed in a transparent way - it is an Interface function only for plug-and-play interconnectability
• Practical implementation for scalability means that we hang them all at once on the back firewall, and initially, on a hanging strip
• They include check valve, since a check valve is not included on a Power Cube

• All circuits outside of drive circuit occur here.
• 14, 28, and 42 GPM can be tapped here
• Tap 42 GPM for large dozer lift cylinders
• Tap 28 for curl
• To accommodate different configurations, allow plugin of multiple ½” hoses to valves

Header

Feed

Wheel Valve at feet

Hydraulic Control Concept Simplified 2

• All circuits outside of drive circuit occur between feed and header
• 14, 28, and 42 GPM can be tapped here
• Tap 42 GPM for large dozer lift cylinders
• Tap 28 for curl
• ¾” hose is rated for 34 GPM
• To accommodate different configurations, allow plugin of multiple ½” hoses to valves

any aux circuit via tee or cross

1” hose

Feed comes from back of cab, plug facing down on top 2’of 5’ cab

2 spool motor 25 GPM $210

Scalability: more holes can be added to feed bar for more feeds

45 GPM Valve

Scalability - fitting sections can be added instead of a plug

Header Scalability

Requirements:

• Pipe body is 1” or successively wider from ½” to 1”
• 2 outlet at 1”
• 6 inputs at ½”
• Angles are favorable for routing within cab

Scalability - sections can be added instead of a plug

BOM:

• [6] 1” tees
• [6] 1” to ½” reducer bushings - $2.3, M
• [6] ½” nips, $1.75
• [1] 1” NPT plug, $2.5

Header With Improved Geometry

Still, the 180 degree fluid turn is not desirable

1” hose to

wheel drive

BOM (need 2x this for forward and return header):

• [6] 1” tees
• [6] 1” to ½” reducer bushings - $2.3
• [6] ½” nips, $1.75
• [7] 1” nips, $2.65
• [1] 1” NPT plug, $2.5
• [2] 1” elbows, $5

1” hose can be set to the required angle for location of valves in cab

½” hose feed from 6 Power Cubes via Connection Panel

1” hose to

wheel drive

Drive Control Geometry Streamlining

• ½” hoses from Power Cubes to Feed Panel - until header 1” hose

Power Cube Source

scalable to 6 Power Cubes by stacking 2 valves next to each other with a stiff connection

return header is just like forward header, except flowing from 1” to the individual Power Cube return hoses.

Cab Module

driver seat

Parallel to Series conversion Selector Valves

power cube feed panel should follow the spacing of the Reurn Header

Right Hand Site (RHS) valve from perspective of driver

LHS Valve

Additional auiliary valves can be placed in front of the 45 GPM valves

40 GPM selector valve

45 GPM

Control Valve

Cab Hydraulics BOM - broken down

Power Cube Source

Cab Module

LHS Valve

• [48] ½” quick coupler pairs
• [4] 40 GPM selector valves
• [4] 45 GPM Control Valve
• [1] 3 Spool 25 GPM motor valve
• [1] 3 Spool 25 GPM cylinder valve w/ float

Cab

• [4] 1”x18” hose
• [10] 1”x24” hose
• [12] 1”x36” hose
• [2] 1”x60” hose
• [12] ½”x48 hose
• [12] ½”x60” hose

Power Cubes:

• [4] ½”x3’ hose
• [4] ½”x6’ hose
• [4] ½”x10’ hose

Implements:

• [4] ½”x12’ hose for rear

Front Loader:

• [2] ½”x6’ hose
• [2] ½”x9’ hose
• [1] ½”x10’ hose
• [1] ½”x12’ hose
• [2] ½”x4’ hose

Interconnection Power Cubes

• [6] 1” ball valves
• 20’ of suction hose - Hydraulics Direct
• [6] 1” hose barbs

Wheel Valve Fittings

• [8] SAE 16 to 1” NPT elbow swivel
• [8] SAE 16 to 1” NPT swivel

Selector Valve Fittings

• [12] 1” NPT swivel, $6
• [12] 1” NPT swivel elbow, $8

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Wheels:

• [4] ½”x6’ hose
• [4] ½”x10’ hose
• [4] ½”x15’ hose

Headers (need x3)

• [18] 1” tees
• [18] 1” to ½” reducer bushings - $2.3
• [18] ½” nips, $1.75
• [21] 1” nips, $2.65
• [3] 1” NPT plug, $2.5
• [6] 1” elbows, $5

General Fittings

• [24] ½” elbows
• [24] ½” tees
• [24] ½” swivels
• [24] ½” elbow swivels
• [24] ½” nips

Aux Valve Fittings

• [4] ¾” crosses
• [12] ¾”-½” reducer bushing
• [8] ½” elbows
• [4] ½” nips

Case Drains

• [6] ¼”x6’ hose -
• [12] ¼” quick coupler pairs
• [8] ¼” NPTF tees
• [18] ¼” hex nips

Arms

• [1] 4”x36”x2” hydraulic cylinder, SAE8
• [1] 4”x30”x2” hydraulic cylinder, SAE8
• [8] sae 8x1/2” NPT elbow swivels

Check Valves

• ½” check valve

Surplus Center BOM

Valves

• [4] 40 GPM selector valves
• [4] 45 GPM Control Valve
• [1] 3 Spool 25 GPM motor valve
• [1] 3 Spool 25 GPM cylinder valve w/ float
• [6] ½” check valve

Cylinders

• [1] 4”x36”x2” hydraulic cylinder
• [1] 4”x30”x2” hydraulic cylinder

Hose

• [6] ¼”x6’ hose
• [4] ½”x3’ hose
• [14] ½”x4’ hose
• [12] ½”x5’ hose
• [10] ½”x6’ hose
• [2] ½”x9’ hose
• [9] ½”x10’ hose
• [5] ½”x12’ hose
• [4] ½”x15’ hose
• [4] 1”x18” hose
• [10] 1”x24” hose
• [12] 1”x36” hose
• [2] 1”x60” hose

Fittings

• [6] 1” ball valves
• [6] 1” hose barbs
• [8] SAE 16 to 1” NPT elbow swivel
• [8] SAE 16 to 1” NPT swivel
• [12] 1” NPT swivel
• [12] 1” NPT swivel elbow
• [18] 1” tees
• [18] 1” to ½” reducer bushings
• [21] 1” nips
• [3] 1” NPT plug
• [6] 1” elbows
• [66] ½” nips
• [32] ½” elbows
• [24] ½” tees
• [24] ½” swivels
• [24] ½” elbow swivels

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• [6] ⅜” NTPM to 1/2” swivel
• [4] ¾” crosses
• [12] ¾”-½” reducer bushing
• [12] ¼” quick coupler pairs
• [8] ¼” NPTF tees
• [18] ¼” hex nips
• [8] sae 8x1/2” NPT elbow swivels

Other

• [11] 3” bearings

Missing:

• [3] 1” tees
• [1] 40 GPM selector valve

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Ebay -[48] ½” quick coupler pairs, [12] ¼” quick coupler pairs

20’ of suction hose - Hydraulics Direct

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Hydraulic Controls - Priorities

Connection Panel

just check valve, no combining of flows

45 GPM motor valve

½”

45 GPM loader valve

each line represents ½” worth of fluid

45 GPM selector valve (2 loaders)

½” hoses until this point

45 GPM selector valve - wheels

45 GPM motor valve

Power Takeoff Panel

1. Parallel and series wheel drive
2. Wheel drive scaled to 6 Power Cubes
3. Loader + curl, 45

Controls Basics

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Deployment

• Start with Cab and single Power Cube controlling 2 motors.
• Parallel drive with series valves - allows one speed

Power

Cube

Motor 1

Motor 2

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• Then rework the system to allow both parallel and series operation of motors. The important details come in when there are 6 Power Cubes for 168 hp - and 6 motors in the system, as in the subsequent pages. The important concept is that by designing the parallel or series operation, we have created 2 speeds without using any gearing.

Power

Cube

Motor 1

Motor 2

• broken line shows location of cab

• Selector valves S selects parallel operation just like above, or routes to a new series circuit
• S1 and S2 have to be pushed in tandem to activate the circuit (see circuit detail)

S1

S2

V1

V2

• Each valve, situated on the left and right sides of the operator - is operated by one hand
• Forward and reverse is available
• Pushing one valve forward and one valve back makes the bulldozer spin in place

V1

V2

Parallel + Series Detail

Left Motor

Power

Cube

14 GPM

• This is looking from the top of the motor. To spin the same direction, bungs on opposite motors must be reversed like this:

(If motors are identical and on opposite sides of MicroTrac, they will spin in opposite directions.)

port A

port B

pulling activates

port A or B? And is this uniform for different manufacturers?

Note: for intuitive use, direction of valve will correstond to forward and backward. Thus, it is important to understand which port is activated in which direction, and which motor port corrosponds to which direction of motion. Further, high speed selection levers should be pushed forward to activate high speed series operation.

Connection Convention Notes:

• Keep orientation of valves uniform: relation of lever, A, and B ports must be consistent (correct rotation direction) and understood (forward and reverse must be intuitive)
• For motors, opposite sides means that bungs have to be reversed
• Set orientation as forward lever (depending on mounting orientation) = port A is pressure on valve is male = port A on motor receives fluid for correction direction of motion is female
• This has to be determined with the actual components; note that this may not be uniform between manufacturers, and open source standards are critical here
• For any 2 connections on opposite sides, whether Parallel or Series - Pressure ports must be reversed in orientation because of mirror symmetry
• Front is connected to front on opposite sides in series
• Front is connected to back in parallel

Forward direction noted by location of Cab

reversed bungs (note crossing)

2 levers are connected so that they are actuated at the same time

P

P

• In series operation, each motor receives 14 GPM

Parallel + Series Detail: Scaling to 2 Power Cubes

Left Motor

P

P

Power

Cube

Power

Cube

connection manifold

check valves to prevent backfeed into power cubes if one power cube is turned off

manifold combines 14 gpm power cube flows into a larger 28 gpm flow

Configuration with 2 Power cubes allows for rated flow through hydraulic motors in parallel and series modes. If there are 3 Power Cubes, additional motors are required to handle the incoming fluid flow. Thus, 2 Power Cubes are the maximum allowable number of Power Cubes for 2 motors.

• In series operation, each motor receives 28 GPM (2 Power Cubes)
• In parallel operation, each motor receives 14 GPM

Scaling to 3 Power Cubes

Left Motor

P

P

Power

Cube

Power

Cube

connection manifold

Power

Cube

• In series operation, each motor receives 21 GPM (1.5 Power Cubes)
• In parallel operation, each motor receives 10 GPM
• Other considerations: if slippage occurs, it should be possible to lock out any slipping motor by disconnecting it and making it freewheel, or by switching to series operation
• Ball valve may be used as a parking or emergency brake to lock out wheels

P

each 40 GPM valve can handle 3 Power Cubes (~42 GPM)

Scaling to 4 Power Cubes

More valves are required to handle additional fluid flow

Left Motor

P

P

Power

Cube

Power

Cube

connection manifold

Power

Cube

P

Power

Cube

• In series operation, each motor receives 28 GPM
• In parallel operation, each motor receives 14 GPM

Scaling to 6 Power Cubes

More valves are required to handle additional fluid flow

P

Power

Cube

Power

Cube

connection manifold

Power

Cube

P

Power

Cube

• In series operation, each motor receives 28 GPM
• In parallel operation, each motor receives 14 GPM

Too crowded: but connect this last motor to valve just like motor below

Power

Cube

Power

Cube

Connection Manifold Concept

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ho

s

e

s

Universal Rotors

Power Cubes

Connection Manifold Detail

• Each Hose Pair runs 14 gallons per minute
• 6 Power Cubes give a total of 84 gallons per minute
• Connection manifold connects all the flows
• A check valve must be used on the Connection manifold so that a Power Cube that gets turned off has no back pressure on it.
• What do the individual pipes connect to?
• 1” pipe carries 60 GPM, recommended

Each Power Cube has a separate ½” hose pair running to the Connection Manifold

Pressure Side Header

Pipe - 1”

Connection Manifold Detail

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• 1” pipe flows 60 GPM
• 1.18” recommended for 85 GPM
• .83” recommended for 42 GPM

1/2”

1/2”

1/2”

1/2”

1/2”

1” hose

1” hose

1” hose

1” hose

1” hose

1” hose

1” hose

1” hose

1” hose

Parallel + Series Operation in One

Power

Cube

Left Motor

Right Motor

A

C

D

40 GPM Selector Valve

In Parallel operation - V1 and V2 control Left-side and Right-side motors independently.

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in Series operation - S1 and S2 are engaged at the same time to switch into series as one lets their hand off V2. S2 essentially opens or closes the connection between B and C, such that the inlet and outlet ports are connected to each other. This means that both motors spin forward or backward (no turning unless one switches back to parallel mode). Practical case is 6 Power Cubes running 6 motors in parallel, then switching to series such that each motor is driven by 2 Power Cubes.

P1

P2

P3

P4

B

S1

S2

V2

V1

crossed because if motors are on opposite sides, they will make tracks spin in opposite directions if connected identically.

Selector Valve Circuit

40 GPM selector valve

Control Valve

• Bidirectional: allows forward and reverse flow to the outlet ports
• Must be used with a Power Beyond plug if there are valves downstream. Otherwise, use a return line.
• When Power Beyond is utilized, the return line must still be used from this valve
• However, when Power Beyond is used - only Valve 1 or Valve 2 can be used at a time.

45 GPM

Control Valve

valve 1

Power Cube

valve 2

power beyond outlet

low pressure return to hydraulic tank

valve 1

Power Cube

valve 2

power beyond outlet closed

low pressure return to tank

Multiple Motors - Adding Motors

Power

Cube

Left Motor

Right Motor

A

C

D

40 GPM Selector Valve

Add motors

P1

P2

P3

P4

B

S1

S2

V2

V1

40 GPM Ball Valve

Left Motor

Left Motor

Right Motor

Right Motor

Parallel + Series, using optional series/parallel selector spool

Left Motor

P

P

Power

Cube

Power

Cube

connection manifold

check valves to prevent backfeed into power cubes if one power cube is turned off

manifold combines 14 gpm power cube flows into a larger 28 gpm flow

Configuration with 2 Power cubes allows for rated flow through hydraulic motors in parallel and series modes. If there are 3 Power Cubes, additional motors are required to handle the incoming fluid flow. Thus, 2 Power Cubes are the maximum allowable number of Power Cubes for 2 motors.

• In series operation, each motor receives 28 GPM (2 Power Cubes)
• In parallel operation, each motor receives 14 GPM

connection manifold

connection manifold

need to use the optional parallel/series selector spool

Design by Nate G.