Danfoss OMT, OMV User guide

Technical Information

Orbital Motors

General

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Technical Information

General, Orbital Motors

Revision history Table of revisions

Date Changed Rev

December 2021 Comprehensive catalogue update 0401

July 2018 updated to Engineering Tomorrow design 0203

June 2015 Minimum speed updated 0202

May 2015 Motor version removed from section 'Motors woth integrated flushing valve CB

November 2014 Converted to Danfoss layout - DITA CMS CA

June 2005 BA

Changed document number from 'BC00000083' and '520L0232' to 'BC152886483554' 0301

2 | © Danfoss | December 2021 BC152886483554en-000401

Technical Information

General, Orbital Motors

A wide range of Orbital Motors

Conversion Factors Orbital Motors, General

Selection of Motor Type

Selection of Motor Size

Bearing Dimensioning

Hydraulic Systems

Orbital Motors Introduction......................................................................................................................................................... 5

Orbital Motors Features............................................................................................................................................................5

Technical Features......................................................................................................................................................................5

Orbital Motors Application Areas..........................................................................................................................................5

Orbital Motors Literature Overview...........................................................................................................................................6

Operating Principle..........................................................................................................................................................................8

Gearwheel set...............................................................................................................................................................................8

Distributor valve..........................................................................................................................................................................8

Disc valve with valve drive................................................................................................................................................. 8

Features of main types................................................................................................................................................................... 9

OMT, OMV......................................................................................................................................................................................9

TMT...................................................................................................................................................................................................9

Motor Variants................................................................................................................................................................................... 9

Wheel motor................................................................................................................................................................................. 9

Short motors...............................................................................................................................................................................10

Ultrashort motor....................................................................................................................................................................... 10

Motors with integrated negative holding brake...........................................................................................................10

Motors with integrated flushing valve..............................................................................................................................11

Motors with tacho connection............................................................................................................................................ 11

Motors with speed sensor..................................................................................................................................................... 12

Build-up of the Function Diagram...........................................................................................................................................13

Continuous operation/intermittent operation/peak load.........................................................................................13

Efficiency......................................................................................................................................................................................14

Volumetric efficiency...............................................................................................................................................................14

Example........................................................................................................................................................................................14

Hydraulic mechanical efficiency..........................................................................................................................................15

Example:.......................................................................................................................................................................................15

Total efficiency...........................................................................................................................................................................16

Minimum speed..............................................................................................................................................................................16

Shaft load and bearing life time............................................................................................................................................... 17

Relationship between Bearing Life Time and Speed........................................................................................................ 17

Relationship between Shaft Load and Bearing Life Time................................................................................................17

Relationship between permissible shaft load and speed............................................................................................... 18

Maximum Radial Shaft Load...................................................................................................................................................... 18

Max. Pressure on the Shaft Seal................................................................................................................................................19

Standard shaft seal (NBR).......................................................................................................................................................19

High-pressure shaft seal (NBR).............................................................................................................................................19

Viton shaft seal (FPM)..............................................................................................................................................................19

Characteristics of sealing materials....................................................................................................................................19

Short/ultra-short motors........................................................................................................................................................20

Drain Line..........................................................................................................................................................................................20

Application..................................................................................................................................................................................20

Oil flow in the drain line......................................................................................................................................................... 20

Braking...............................................................................................................................................................................................20

Braking torque...........................................................................................................................................................................21

Opening pressure for the dual shock valve.....................................................................................................................21

Replenishment...........................................................................................................................................................................21

Seeping.........................................................................................................................................................................................23

Brake Motors....................................................................................................................................................................................23

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Technical Information

General, Orbital Motors

Contents

OMT FX, OMT FL and TMT FL................................................................................................................................................24

OMT FH.........................................................................................................................................................................................24

Installation, Starting Up, Maintenance and Oil Types.......................................................................................................25

Design in brief............................................................................................................................................................................25

Combination in brief............................................................................................................................................................... 25

Starting up and running in the hydraulic system......................................................................................................... 25

Signs of air in the hydraulic system....................................................................................................................................26

If there is air in the system.....................................................................................................................................................26

During operation...................................................................................................................................................................... 26

Maintenance...............................................................................................................................................................................26

Oil Types.......................................................................................................................................................................................26

Mineral oils.............................................................................................................................................................................26

Non-flammable or biodegradable fluids....................................................................................................................26

Temperature, Viscosity and Filtering...................................................................................................................................... 27

Temperature...............................................................................................................................................................................27

Viscosity........................................................................................................................................................................................27

Filtering........................................................................................................................................................................................ 28

4 | © Danfoss | December 2021 BC152886483554en-000401

Technical Information

General, Orbital Motors

A wide range of Orbital Motors

Orbital Motors Introduction

Danfoss is a world leader within production of low speed orbital motors with high torque. We can offer more than 1500 different orbital motors, categorized in types, variants and sizes (including different shaft versions).

The motors size vary (rated displacement) from 130 to 800 cm3 [7.9 to 48.9 in3] per revolution.

•

Speeds range up to approximate 600 min-1 (rpm). Maximum operating torques up to 3400 N•m [30090 lb•in] (peak) and maximum outputs up to 70 kW [95

hp].

Orbital Motors Features

•

Motor sizes:

OMT and OMV

‒

TMK

‒

TMT

‒

TMTHW

‒

TMVW

‒

Smooth running over the entire speed range Constant operating torque over a wide speed range High starting torque High return pressure without the use of drain line (high pressure shaft seal) High efficiency High radial and axial bearing capacity Long life under extreme operating conditions Robust and compact design For applications in both open and closed loop hydraulic systems Suitable for a wide variety of hydraulics fluids

Technical Features

The program is characterized by technical features appealing to a large number of applications and by motors that can be adapted to a given application.

Adaptions comprise the following variants:

Motors with:

•

integrated negative holding brake

‒

speed sensor

‒

black finish paint

‒

Short motors without bearings or Ultra short motors

•

Wheel motors with recessed mounting flange

•

Orbital Motors Application Areas

The orbital motors are used in the following application areas:

Construction equipment

•

Agricultural equipment

•

Material handling & Lifting equipment

•

Forestry equipment

•

Lawn and turf equipment

•

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Technical Information

General, Orbital Motors

A wide range of Orbital Motors

Machine tools and stationary equipment

•

Marine equipment

•

Special purpose

•

Orbital Motors Literature Overview

A general catalog of all Orbital Motors with technical data gives a quick motor reference based on: selection of orbital motor, function in hydraulic systems, power, torque, speed and capabilities. More detailed information can be found in an individual motor catalogs.

Literature title Literature type Reference number

Orbital Motors in General Technical Information BC152886483554 OMT and OMV Orbital Motors Technical Information BC152886483862 TMK, TMKW, TMK FL Orbital Motors Technical Information BC152886483785 TMT, TMTU, TMTW, TMT FL Orbital Motors Technical Information BC152886483631 TMTHW Orbital Motors Technical Information BC152986483537

Technical Information

General, Orbital Motors

Conversion Factors

1 Nm = [8.851 lbf.in] 1 cm3 = [0.061 in3] 1 N = [0.2248 lbf ] 1 l = [0.22 UK gal] 1 bar = [14.50 psi] 1 l = [0.264 US gal] 1 mm = [0.0394 in] °F = [1.8 °C + 32]

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Technical Information

General, Orbital Motors

Orbital Motors, General

Operating Principle

Orbital motors convert hydraulic energy (pressure, oil flow) into mechanical energy (torque and speed). Danfoss orbital motors are of fixed displacement high-torque design. For a given oil flow and given

pressure the displacement (size of motor) determines the speed and torque. For a given displacement (size of motor) the speed is determined by the oil flow rate and the torque is determined by the pressure differential.

Gearwheel set

The operating principle of the motors is based on an internal gear design, consisting of a fixed external gear reaching against an internal gear through which the output torque and speed are transmitted.

Distributor valve

The distributor valve is driven synchronously by the internal gear through a cardan shaft ensuring that the individual chambers of the motor are filled and emptied precisely - without losses.

Disc valve with valve drive

OMT, OMV and TMT motors have a disc valve: The distributor valve has been separated from the output shaft and it is driven by a short cardan shaft [valve drive]. A balance plate counterbal-ances the hydraulic forces around the distributor valve.

A: Output shaft D: Valve drive B: Cardan shaft E: Check valve C: Gearwheel set F: Disc valve

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151-887.10

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Technical Information

General, Orbital Motors

Selection of Motor Type

Features of main types

OMT, OMV

Gear rim with rollers

•

Disc valve with separate valve drive

•

Output shaft supported in tapered roller bearings

•

TMT

Gear rim with rollers

•

Disc valve with separate valve drive

•

Output shaft supported in tapered roller bearings

•

Motor Variants

OMT, OMV

OMT and OMV are suitable for continuous operation under rough operating conditions: e.g. high pressures, thin oil, or frequent reversals. The tapered roller bearings make the motors suitable for absorbing static and dynamic radial loads. Besides the separately driven and hydraulically balanced disc valve, hydraulic and mechanical losses are reduced to a minimum. This gives the motors high efficiency even at high pressures, and good starting characteristics.

TMT

The marked for hydraulic motors has developed generally increasing expectations of the motor performance, and espacially of a higher pressure level. On some applications the present motor program no longer fulfils the marked demand. The TMT motors comply with these expectations providing the same good characteristics as the OMT and OMV motors.

If the application requires very smooth running at low speeds the choice of OMT, OMV or TMT is recommended.

Wheel motor

OMT and OMV motors are available in wheel motor versions. The recessed mounting flange makes it possible to fit a wheel hub or a winch drum so that the radial load acts midway between the two motor bearings. This gives the best utilisation of the bearing capacity and is a very compact solution. Type designations of wheel motors are OMTW and OMVW.

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