Parker United Kingdom

How to Select a Hydraulic Cylinder Accessory

How to Choose a Hydraulic Cylinder Accessory - Parker Hannifin, Hydraulic Cylinder DivisionHow do I choose an accessory for an HMI, HMD or HMIX Series cylinder and why is the right accessory critical?  

Cylinder mounting accessories and mountings transmit the force applied by a cylinder to the surface to which it is attached, and to the machine member to which it is connected. Mounting accessories and mountings also control alignment and resist movement which could result in fatigue failure. A correctly specified mounting accessory:

  • increases productivity
  • reduces downtime
  • provides greater machine and operator safety
  • reduces maintenance

At the piston rod end – accessories are selected by reference to the rod end thread. At the cap end – accessories are selected by cylinder bore size.

 

Download the guide and select the right cylinder accessories for your application.

 

How to Select a Hydraulic Cylinder Accessory 

 

 

Piston rod ends

Accessories at the head end of a cylinder attach directly to the piston rod end, and Parker offers a range of different piston rod diameters and rod end styles, as shown in the table. Different thread forms, diameters and lengths give flexibility to the machine designer and ensure reliable performance for the end user.

How to Select a Hydraulic Cylinder Accessory - Table showing rod end styles and thread forms - Parker Hannifin Hydraulic Cylinder Division

 

Fatigue Failure – is the rod suitable for the application?

Cycling a load subjects the piston rod to tensile and compressive forces, and these create the highest risk of fatigue failure at reduced diameters and threads. Depending on the diameter of the piston rod and the size of the threads attaching both the rod end accessory and the internal piston, fatigue failure can occur if an unsuitable piston rod is chosen. In all cases, rod end accessories should be securely butted against the rod shoulder.

Push Loads – 12 mm and 14 mm diameter piston rods with four wrench flats should be restricted to 160 bar working pressure.

Pull Loads – Where a small diameter rod option is to be used in high cycling, pull load application at or close to 210 bar working pressure, please consult Parker for guidance.

How to Select a Hydraulic Cylinder Accessory - exploded view of cylinder and rod ends - Parker Hannifin Hydraulic Cylinder Division

Key

  1. Rod clevis For use with eye bracket (5) and pivot pin (4)
  2. Rod eye with plain bearing For use with clevis bracket (6) and pivot pin (4)
  3. Rod eye with spherical bearing For attachment to customer mounting.
  4. Pivot pin – for use with 1, 2, 5 and 6
  5. Eye bracket For use with rod clevis (1) and pivot pin (4) or at the cap end of a rear clevis-mounted cylinder, style BB (pivot pin supplied with cylinder)
  6. Clevis bracket For use with the rod eye with plain bearing (2) and pivot pin (4) 

 

HMI, HMD and HMIX cylinder ranges

All rod ends can be supplied with two or four wrench flats. See Fatigue Failure, above, regarding pressure limitations where four flats are specified.

HMI cylinders are available with all of the rod sizes, rod end styles and rod end threads are shown in the table.

HMD cylinders are only available with rod diameters No. 1 and No. 2, and only with the rod end threads highlighted in blue in the table.

HMIX cylinders are available with bore sizes from 40 mm to 200 mm, with all of the rod sizes, rod end styles and rod end threads are shown in the table.

 

Selecting a piston rod end type

Standard Male Rod Ends  - The large thread diameter of the standard rod ends, Code 1 (with four wrench flats) or Code 4 (with two wrench flats), provides the maximum resistance to fatigue failure and is recommended for all applications. The rod end accessory or attachment should be securely butted up against the rod shoulder.

Small Diameter Male Rod Ends - Code 2 rod ends (with four wrench flats) or Code 7 rod ends (with two wrench flats) are for use with rod eyes with spherical bearings. They allow the same diameter of pivot pin to be used at both the head and cap ends of the cylinder – see Example 2 below.

Female Rod Ends - Code 5 rod ends (with four wrench flats) or Code 9 rod ends (with two wrench flats) are used where the rod end attachment requires a female thread. They should not be used on 160 mm or 200 mm bore cylinders with a stroke of 50 mm or less.

 

How to Select a Hydraulic Cylinder Accessory - various rod ends - Parker Hannifin, Hydraulic Cylinder Division

Non-Standard Rod Ends - Non-standard piston rod ends are designated Style 3. For more information, please contact us. 

Example 1 – Cylinder cap end accessory 

Cylinder Specification: 

  • Cap fixed clevis (style BB – supplied complete with pivot pin), 80 mm bore 

Accessory Specification: 

  • Position – cap end of cylinder
  • Mounting – pivoting
  • Alignment – fixed, ie: movement in a single plane of motion 

Recommended Accessory: Eye bracket 

Accessory Sizing: 

  1. Identify pin diameter at cap end of cylinder – 28 mm
  2. Select part number of corresponding eye bracket from web page or catalogue* – 144813 
  3. Check dimensions. Use CAD view of 144813 on web page or refer to catalogue* to establish that the pin height, arc of travel etc. are suitable for the application. 

 

Example 2 – Piston Rod End Accessory 

Cylinder Specification: •

  • Cap fixed eye with spherical bearing (style SBd), 63 mm bore
  • Large diameter (No. 2) piston rod

Accessory Specification: 

  • Position – piston rod end 
  • Mounting – pivoting
  • Alignment – to accommodate up to 4° of misalignment 

Recommended Accessory: Rod eye with spherical bearing 

Accessory Sizing: 

  1. Select Code 7 rod end, to suit rod eye with spherical bearing
  2. Identify rod end thread from table opposite: M20x1.5 
  3. Select part number of rod eye with spherical bearing from web page or catalogue* to suit thread – 145258 
  4. Confirm pin diameter – 30 mm at each end of cylinder 
  5. Check dimensions. Use CAD view of 145258 on web page or refer to catalogue* to establish that pin diameter, pin height, arc of travel etc. are suitable for the application.

* Full information for specifying a Parker HMI or HMD hydraulic cylinder can be found in catalogue HY07-1150/UK 

* For the HMIX feedback cylinder see catalogue HY07-1175/UK.

Download the guide and select the right cylinder accessories for your application.    

How to Select a Hydraulic Cylinder Accessory

 

Additionally you can also configure a cylinder and download the CAD file instantly by using our eConfigurator tool on parker.com

 

Related content on hydraulics:

Top Innovative Products and Systems for Heavy-Duty Vehicles

How Many Times Can I Reassemble a Hydraulic Fitting?

Essential Factors for Selecting Hydraulic Cylinders for Tough Operating Environments in Aluminium Processing

Categories
Recent posts by author

How to Select a Hydraulic Cylinder Accessory

How do I choose an accessory for an HMI, HMD or HMIX Series cylinder and why is the right accessory critical?   Cylinder mounting accessories and mountings transmit the force applied by a cylinder to...

Rail Vehicle Design Engineers Should Know This About EN 45545

The European standard EN 45545 was introduced in 2013 with a transitional period until 2016 and raises the level of requirements to the previous national standards, which have now been withdrawn. The...

Most Reliable Fitting for Rail: EO-2 Soft-Sealing Fitting for Leak-Tightness

The reliability of every component is significant for the design engineer of modern railway vehicles if they are to function smoothly in the long term. The EO-2 fitting has been extremely reliable for...
Comments

Have a question about Parker products or services? We can help: Contact Us!

Note to How to Select a Hydraulic Cylinder Accessory


Please note that, in an effort to combat spam, comments with hyperlinks will not be published.

Leave a comment





Captcha