Regenerative Circuits
for Mobile
and Industrial Applications
Mark Anderson
20 Nov 2013
Definition
Connecting the rod end to the base end of a single rod cylinder during the extend cycle.
Fluid that exits the rod end is added (regend) to the base end.
All regen circuits increase speed, and reduce force.
Toyota Prius Hydraulic Launch Assist
Regeneration
Definition
Standard Regen
Definition
Simplified #1 Regen Simplified #2
Definition
Double Rod Regen
2:1 ratio
Definition
Pros
Cons
Good for Press circuits: when a large portion of the cycle is pushing air
Quicker cycle times with a smaller motor/pump/reservoir
Equal force and speed when used with a 2:1 cylinder
Cheaper, smaller, and fewer seals than a double rod cylinder
More complex plumbing and valving
More logic required when shifting from high speed to high force
Difficult to build exactly a 2:1 cylinder
Definition
2:1 ratio High Ratio
(Large Rod)
Low Ratio
(Small Rod)
Examples
Power Steering
2:1 cylinder
Examples
Full Time Regen
Internal External
Examples
Solenoid Switched Regen
Examples
Pressure Activated Regen
Externally piloted sequence valve
Examples
Pressure Sensitive Regen
Sun circuit with counterbalance valve
Examples
Regen logic near cylinder
Examples
Regen with rotary flow divider
Examples
Regen with logic elements
Control Logic
Examples
Proportional Regen with internal switching
Parker Hannifin D91FB Z
Examples
Proportional Regen (5 position spool) with External plumbing
Eaton Vickers 133C spool
Examples
Proportional Regen (4 position spool) (internal)
Bosch Rexroth
Examples
Proportional Regen symbols
Traditional Preferred
Examples
Definition of Efficiency
More
Energy Level
Less
Meter In Control
Load
Meter Out Control
Efficiency = Work Out / Energy In
Examples
Servo valve vs. Proportional valve
High Delta P = High System Stiffness
You pay for Good Control (stiffness) with less efficiency
Servo rated 70bar (1000psi) Proportional rated 10bar (150psi)
Max
Min0% 33% 67% 100%
Powerto Load
System Delta P% across valve
Examples
Accuracy vs. Precision
Precise.
Not Accurate
Precise and Accurate Accurate.
Not Precise
Examples
Proportional Regen two valve solution
Q=100
Ext=150
Ret=200
Ext= 50
Ret=100
2:1 ratio
Examples
Proportional Regen internals
Centered
P to B
P to A
Continental Hydraulics VED07M
Examples
Proportional Regen internals
P to A B to P
Examples
Proportional Regen two valve solution
Q=100
Ext=150
Ret=200
Ext= 50
Ret=100
2:1 ratio
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