Flexibility
Technological diversity
Powerful
Machine design
Generating grinding, profile grinding and internal grinding in one machine
Flexibility is essential for job shops and small lot sizes. The new LGG series has been specially designed for universal use, as well as for large series production. It combines three technologies: Generating grinding, profile grinding and internal grinding. This technological diversity provides the universal user with maximum benefit and a secure investment for the future.
This machine can be configured for individual applications, so it is perfect for use in the production of large batches. This is where external automation systems such as a plastic chain conveyor or a robot system are used.
The LGG is the most powerful generating and profile grinding machine of its class on the market. With the new GH 320 CB grinding head, it is now also possible to efficiently grind superior quality workpieces up to module 14. The LGG 700 M is a manual gear grinding machine that can grind workpieces up to 500 mm (generating) and up to 700 mm for profile grinding.
X1 - radial movement of column slide | V1 - tangential movement of tool | Z1 - axial travel of grinding head | B1 - rotary movement of tool | C2 - rotary movement of workpiece | A1 - swivel movement of tool | Z4 - vertical travel of steady column | C3 - rotary movement of ringloader
LGG 700 M
Liebherr also offers a manual generating and profile grinding machine for small batch sizes and outstanding flexibility.
- Generating grinding max. workpiece diameter (mm): 500
- Profile grinding max. workpiece diameter (mm): 700
The machine is exclusively loaded manually. A handling device (crane) mounted on the machine roof and an NC-swiveling tailstock make manual loading much more simple.
External and internal grinding heads
Process-optimized external grinding heads and internal grinding arms are available for the LGG. Balancing systems inside the spindle are used in both external grinding heads (GH 320 and GH 240 CB). On the GH 320 CB, the balancing system is integrated in the arbor.
High drive power and speeds are major advantages – for example, when using new grinding materials. The modern tool holding makes it possible to replace the grinding arbor quickly and easily.
Small grinding tool diameters are available for collision-critical workpieces and for special tooth corrections.
With the GH 320 CB grinding head, it is now also possible to efficiently grind optimal-quality workpieces up to module 14 mm.
GH 240 / 200 CB
Speed (rpm): 12,000
Grinding spindle drive power (kW): 28.5
Max. grindable module generating grinding (mm): 7
Max. grindable module profile grinding (mm): 14
Electro-plated CBN tools: Yes
Dimensions of grinding worm: (DxLxW): 240x200x76.2
Technical data GH 200 CB
Speed (rpm): 17,000
Grinding spindle drive power (kW): 28.5
Max. grindable module generating grinding (mm): 5
Max. grindable module profile grinding (mm): 14
Electro-plated CBN tools: Yes
Dimensions of grinding worm: (DxLxW): 240x200x40 (76.2)
GH 320
Speed (rpm): 7000
Grinding spindle drive power (kW): 28.5
Max. grindable module generating grinding (mm): 9
Max. grindable module profile grinding (mm): 14
Dimensions of grinding worm (DxLxW) (mm): 275(320)x160x160
GH 320 CB
Speed (rpm): 10,000
Max. cutting speed (m/s): 80
Max. grindable module generating grinding (mm): 14
Max. grindable module profile grinding (mm): 14
Max. shift distance (mm): 350
Dimensions of grinding worm (DxLxW) (mm): 320x250x110
Feature: Internal grinding arms are available for all grinding heads.
Can be used with LGG 300, LGG 380, LGG 500 and LGG 700 M
Fast and easy changeover
The adaptable internal grinding arms can be mounted quickly and easily on the external grinding head and are driven using the main drive. Other grinding heads can be provided on request.
In only 30minutes from external to internal grinding
Video
Generating grinding planetary gears, module 14, on the LGG 500 generating and profile grinding machine
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On-board inspection: Gear check in the machine
All grinding heads can be equipped with an optional swivel-in probe for gear checking.
Gear measurement
- Profile and lead
- Concentricity, single and cumulative pitch
- Twist check
- Measuring system for grinding stock removal
- Rolling measurement
- Determining dimension measurement
Mobile or stationary meshing sensor
Technology
Prepared for the future
Type of gears
- Asymmetric profile
- Beveloid gears
- Double helical gears
- Cycloidal gears
Gear modification
- Profile and lead modification
- Free flank form
Cycloidal gears
For cycloidal drives, certain requirements must be met, such as dimensional precision, a high-quality surface, an excellent profile and pitch as well as rollers that fit perfectly to the inner ring. Liebherr has developed something new for cycloidal gears: Now, cam disks with an external gear can be produced via generating grinding using not only single but also perfectly adapted double clamping. Depending on the individual batch-size requirements, which means that besides conventional profile grinding, an additional grinding method for cam disks is now available to users.
Generating grinding asymmetric gears
Asymmetric gears compensate for unequally distributed loads.
The advantages of asymmetric gears are obvious:
- Reduced tooth root clamping forces and Hertzian flank stresses
- Improved specific sliding
- Increased surface durability and tooth root strength
- Increased power density (load capacity in relation to gear size)
- Longer service life
- Increased efficiency
- Reduced noise and vibration excitation
- Increased operational reliability
Requirements when generating grinding asymmetric gears
Machine technology:
- Centering of the dresser/grinding worm
- Centering of the asymmetric grinding worm/workpiece
- Initial profiling and tracking of the asymmetric profile at every dressing cycle
- Precise control technology for dynamic tooth flank contact sequences
Technology:
- Coordination of dressing and grinding parameters
- Selection of appropriate grinding worm specifications
Topological modifications
- TF twist-free grinding
- DFT deviation-free topological grinding
- GER generated triangle-shaped end relief
Modifications for noise reduction
- SSG noise-reduction shift strategy
- NEO noise excitation-optimized modifications
Generating grinding with small tools
Finishing grinding or polishing
Why modified and/or super-finished leads?
Motivation:
- Improved wear behavior
- Reduction of friction losses
- Increased flank and tooth root strength
- Increased efficiency
- Longer service life (gear and gearbox)
Our solution: Finish grinding or polishing
Lower surface roughness can be achieved with finish grinding or polishing. This increases the power density and gear efficiency.
Generating or profile grinding with dressing-free CBN
CBN generating grinding
- Short machining times (two-cut strategy)
- No dressing required
- Very low risk of grinding burn (short contact time, good thermal conductivity of CBN and steel basic body)
- Universal tool design
- Very long tool life
- Robust process with high process stability
- Module range 1.0 - 5.0mm
- External gears with a high toothed length
- Large batches, perfect for three-shift operation
- Mono worm and rough-and-finish combination
- Available in various dimensions:
Diameter 60 /140 / 170mm
Width 2x 96 / 140 / 200mm - Tool design:
Steel basic body, mono-layer CBN coating
Can be re-coated 10-15 times
Metallic, nickel-based bond - Standard CBN grain sizes:
B76 and B91 for finishing
B251 for roughing
CBN profile grinding
- Very high profile quality
- Pressure angle can be corrected by CNC (A, V and X axes)
- Long tool life
- Grinding of non-generating profiles and complex geometries
- Module range 1.0 - 8.0mm
- External and internal gears
- Collision-critical gears (discs Ø < 30mm)
- Small and medium-sized batches
Integrated centrifugal device
Automation
Easy to operate
The new optimized control panel LHStation & LHMobile
With the control panel, Liebherr intelligently divides the programming and operation of the machine between two system parts: The large, fixed monitor unit LHStation for data input and process monitoring and the standardized, mobile handheld terminal LHMobile with context-sensitive user guidance during setup. Both units have a multi-touch surface as well as tactile elements for optimum operating speed and operating safety.
Mobile handheld terminal LHMobile
- 10-inch multi-touch as standard
- Context-sensitive views such as PLC/NC keys and program statuses
- Wired signal transmission for maximum safety
The programming system by Liebherr: 25% faster setup time
With the LHGearTec software, the system constantly guides users when entering workpiece and tool data, as well as during workpiece correction and process monitoring. The user guidance has been defined in intensive cooperation with designers and users.
Technical data
Variants | LGG 300 | LGG 380 | LGG 500 | LGG 700 M |
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