Helac L20 Series Installations- und Betriebsanleitung
Helical Hydraulic
Rotary Actuators
L20 Series Service & Repair Manual
2Parker Hannifin Corporation
Helac/Cylinder Division
Enumclaw, Washington USA
www.helac.com
Helical, Hydraulic Rotary Actuators
L20 Series Service & Repair Manual
Catalog HY34-1120
Table of Contents
Table of Contents
Introduction
Table of Contents..................................................................................................................................................... 2
Product Introduction................................................................................................................................................. 3
General Safety Guidelines....................................................................................................................................... 3
Product Identication ............................................................................................................................................... 4
Operation Technology.............................................................................................................................................. 5
Tools
Tools Required......................................................................................................................................................... 6
Drawings
Spare Parts.............................................................................................................................................................. 7
Assembly Drawing................................................................................................................................................... 8
Exploded View......................................................................................................................................................... 9
Parts List..................................................................................................................................................................10
Disassembly
Before Disassembly................................................................................................................................................. 11
Disassembly ............................................................................................................................................................ 11
Inspection ................................................................................................................................................................16
Assembly
Assembly ................................................................................................................................................................17
Post Assembly
Grease Thrust Washers...........................................................................................................................................22
Testing the Actuator.................................................................................................................................................23
Installation and Bleeding..........................................................................................................................................24
Troubleshooting Guide ........................................................................................................................................... 25
Warranty Information ............................................................................................................................................... 26
3Parker Hannifin Corporation
Helac/Cylinder Division
Enumclaw, Washington USA
www.helac.com
Helical, Hydraulic Rotary Actuators
L20 Series Service & Repair Manual
Catalog HY34-1120
Product Introduction & Safety Guidelines
General Safety Guidelines
Product Introduction
Many L20 actuator applications have several pinch
points with the potential for severe injuries. Use
extreme caution and remain clear of all rotating
components when bleeding the hydraulic system
and whenever the machine is in operation.
After rebuilding or repairing an actuator, it is
necessary to bleed all air from the actuator as well
as the hydraulic system of the machine. See page
25 for bleeding instructions.
Exercise extreme caution while bleeding the
actuator -- keep hands, ngers, and other limbs a
safe distance from all rotating components.
For over 45 years, Helac Corporation has
been recognized for innovation in design of
hydraulic rotary actuators and construction
equipment attachments. Helac products
are renowned for their tremendous torque
output, compact congurations, exceptional
load bearing capabilities, and rugged,
reliable performance. Over 1,000 mobile,
industrial, construction and mining machinery
manufacturers around the world depend on
Helac actuators to perform such functions as
rotation, positioning, manipulation, vehicle
steering and indexing. Helac's L20 Series
rotary actuators are used widely to rotate work
platforms on self-propelled aerial lifts where
they have become the industry standard.
The L20 Series is available in dierent sizes
and various mounting congurations (for more
details see page 4).
Avoid personal injury and
machinery damage:
Read the Service and Repair Manual
for proper installation, maintenance
and repair procedures.
Spraying fluids.
Contents under pressure.
Wear approved eye protection.
Use caution when removing
port plugs and fittings.
To avoid contamination
to machined parts:
Make sure work area is clean.
To avoid injury or damage
to product:
Secure product to slotted table or vise.
4Parker Hannifin Corporation
Helac/Cylinder Division
Enumclaw, Washington USA
www.helac.com
Helical, Hydraulic Rotary Actuators
L20 Series Service & Repair Manual
Catalog HY34-1120
Product Indentification
Product Identification
Each Helac actuator is individually serial
numbered. The serial number is a ve or six digit
number and must be provided before parts and/
or service issues can be addressed.
The serial number can be found on the
Identication (ID) Tag that is axed to all
actuators.Thetagisathin,silvercolored,plastic
materialwithaself-adhesivebacking.Information
is imprinted in black. The tag is located either
on the side plate or on the housing tube of the
actuator. In some cases, the ID tag may be
painted over by the OEM (Original Equipment
Manufacturer). Typical sample tag locations are
seen below. Note that the model number may
begin with either "HP" or "L20".
Additionally, the serial number of the actuator is
stampedontothesideplateorthehousingtube.
It may be necessary to remove paint to expose
the serial number.
IftheIDtagisnotattachedtotheactuatorand/or
the stamped serial number cannot be located,
the basic actuator model can be identied by
measuring the outer diameter of the drilled and
tapped shaft ange.
Model Flange Diameter
L20-4.5 4.10” (104.14 mm)
L20-8.2 4.60” (116.84 mm)
L20-15 5.60” (142.24 mm)
L20-25 6.70” (170.18 mm)
L20-30 7.20” (182.88 mm)
L20-39 7.70” (195.58 mm)
5Parker Hannifin Corporation
Helac/Cylinder Division
Enumclaw, Washington USA
www.helac.com
Helical, Hydraulic Rotary Actuators
L20 Series Service & Repair Manual
Catalog HY34-1120
Operation Technology
OperationTechnology
The L20 Series rotary actuator is a simple
mechanism that uses Helac's sliding spline
technology which converts axial piston motion
into powerful shaft rotation. As seen in the
illustrationbelow left,eachactuatoriscomposed
of a housing with an integral ring gear (1) and
only two moving parts: the central shaft (2),
and the annular piston sleeve (3). Note the L20
actuator shaft features an integral mounting
ange and bearing which are not shown in the
illustration.
Helical spline teeth machined on the shaft
engage matching splines on the inside diam-
eter of the piston. The outside diameter of the
pistoncarriesasecondsetofsplines,of opposite
hand, which engage the matching splines of the
housing's ring gear.
As hydraulic pressure is applied, the piston is
displaced axially within the housing - similar
to the operation of a hydraulic cylinder - while,
simultaneously, the splines cause the shaft to
rotate. When the control valve is closed, oil is
trapped inside the housing, preventing piston
movement and locking the shaft rmly in position.
Theshaft issupported radiallybythelargeupper
radial bearing and the lower radial bearing (see
drawings on pages 8 and 9). Axially, the shaft
is separated from the housing by the upper and
lower thrust washers. The end cap is adjusted
for axial clearance and locked in position by set
screws or pins.
The L20 Series is available in several dierent
sizes. All L20 Series actuators have the same
internal design and basic components, though
congurations of parts may be slightly dierent
depending on model.
Many L20 actuators are equipped with factory
installed counterbalance valves, which perform
four major functions.
• Protectstheactuatorintheeventofoverload
• Enables the actuator to hold position without
drifting when external loads are applied
• Reduces hydraulic backlash by pressuring
the hydraulic uid
• Providesaconstantcontrolledrateofrotation
in over-center load conditions
Bars indicate starting positions of piston
and shaft. Arrows indicate direction they
will rotate. The housing with integral ring
gear remains stationary. For clarity, the
shaft ange, bearings, and end cap are not
shown.
Applying uid pressure will displace the
piston axially while the helical gearing causes
the piston and shaft to rotate simultaneously.
The double helix design compounds rotation:
shaft rotation is about twice that of the piston.
Applying pressure to the opposite port will
return the piston and shaft to their original
starting positions.
3
2
1
6Parker Hannifin Corporation
Helac/Cylinder Division
Enumclaw, Washington USA
www.helac.com
Helical, Hydraulic Rotary Actuators
L20 Series Service & Repair Manual
Catalog HY34-1120
Tools Required
Tools Required
MAKING A SEAL TOOL
The seal tool is merely a customized stan-
dard at head screwdriver.
1. Heat the at end with a torch until it
glows.
2. Secure the heated end of the screw-
driver in a vise and bend the heated end
to a slight radius.
3. Round o all sharp edges of the heated
end to a polished nish. The tool may be
modied slightly to your own personal
preference.
Several basic tools are required for the
disassembly and reassembly of the actuator. The
tools and their intended functions are outlined
below:
1. PIPEVISE
2. TORQUEWRENCH
Removal and replacement of port plugs and
set screws.
3. ASSORTED SCREWS
4. SAFETY GLASSES
5. END CAP REMOVALTOOLS (provided with
Helac seal kit).
6. DRILL
7. FLASHLIGHT
Helps in locating and examining timing marks,
component failure and overall condition.
8. RUBBER MALLET
Removal and installation of shaft and piston
sleeve assembly.
9. PLASTIC MANDREL
10. PRY BAR
Removal of end cap and manual rotation
of shaft.
11. FELT MARKER
Highlights timing marks and outlines troubled
areas. Permanent ink is recommended.
12. T-HANDLE SCREW EXTRACTOR
13. HEXWRENCH SET
Removal and replacement of port plugs and
set screws (106,113).
14. SEALTOOLS
Removal and installation of seals and wear
guides. Directions on making a seal tool are
provided at bottom.
15. PUNCH
16. DOWEL PINS
Removal and installation of end cap.
6.
1.
2. 3. 4.
8.
7.
9. 10.
5.
11. 12. 13.
14. 15. 16.
7Parker Hannifin Corporation
Helac/Cylinder Division
Enumclaw, Washington USA
www.helac.com
Helical, Hydraulic Rotary Actuators
L20 Series Service & Repair Manual
Catalog HY34-1120
Spare Parts & Technical Support
Technical Support
Spare Parts
Sparepartsmustbeorderedthroughthevehicle/
machineOEM.Sealsandbearingsareavailable
as complete kits only. In order to obtain the
correct parts, it is essential to provide the serial
numberoftheactuatortoberepaired,seeProduct
Identication section on page 4. To identify spare
partsrequired,refertotheAssemblyDrawingon
page 8 and Parts List on page 10.
Technical support is available from Helac Corporation, Monday through Friday 7 am to 4 pm
Pacic Standard Time by calling 800-327-2589. If possible, please have the serial number of the
actuator available. (The serial number is stamped into the housing of the actuator-see page 4).
Spare Parts
8Parker Hannifin Corporation
Helac/Cylinder Division
Enumclaw, Washington USA
www.helac.com
Helical, Hydraulic Rotary Actuators
L20 Series Service & Repair Manual
Catalog HY34-1120
106
2
113
4
109
2
401
A
A
420.1
420.2
200
202
02
421
206
304
205
03
400
204
421
04
206
304
205302
01
207
103
2
302
VIEW A-A
90°
113
4
109
2
401
106
2
Assembly Drawing
Assembly Drawing
Typical L20 Series Actuator
Clevises May Be Dierent
9Parker Hannifin Corporation
Helac/Cylinder Division
Enumclaw, Washington USA
www.helac.com
Helical, Hydraulic Rotary Actuators
L20 Series Service & Repair Manual
Catalog HY34-1120
421
113
2
02
206
304
205
302
200
202
03
420
401
204
207
302
205
304
206
04
109
2
113
4
421
106
01
Template Rev J - T.U.
Exploded View
ExplodedView
10 Parker Hannifin Corporation
Helac/Cylinder Division
Enumclaw, Washington USA
www.helac.com
Helical, Hydraulic Rotary Actuators
L20 Series Service & Repair Manual
Catalog HY34-1120
Parts List
Parts List
Parts
ITEM DESCRIPTION QUANTITY
01 HOUSING 1
02 SHAFT 1
03 PISTON SLEEVE 1
04 END CAP 1
Hardware
ITEM DESCRIPTION QUANTITY
103 SEALING SCREW (OPTIONAL) 2
106 PORT PLUG 2
109 LOCK PIN 2
113 CAP SCREW 6
Bearings
Sold as "kit" only
ITEM DESCRIPTION QUANTITY
302 WEAR GUIDE 2
304 THRUST WASHER 2
Accessories
ITEM DESCRIPTION QUANTITY
400 STOP TUBE (OPTIONAL) 1
401
COUNTERBALANCE VALVE (OPTIONAL)
1
403
MOTION CONTROL VALVE (OPTIONAL)
1
420 BUSHINGS (OPTIONAL) 2-4
421 BUSHINGS (OPTIONAL) 2
Spare Parts
Spare parts must be ordered through the vehicle/machine OEM. Seals and bearings are available as complete kits
only. In order to obtain the correct parts, it is essential to provide the serial number for the actuator to be repaired.
See Product Identication on Page 4. To identify spare parts required, refer to the Assembly Drawing, Exploded View
Drawing and the Parts List.
Seal and Bearing kits can be ordered online at
http://www.helac.com/store/
Seals
Sold as "kit" only
ITEM DESCRIPTION QUANTITY
200 T-SEAL 1
202 T-SEAL 1
204 O-RING 1
205 CUP SEAL 2
207 BACK-UP RING 1
206 EXCLUSION SEAL 2
HYDRAULIC FLUID: ISO-VG-46
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