Measurement solutions keep gears shifting smoothly

Aug 31, 2023

Synchronizer rings are key components in manual, automatic and dual-clutch transmissions. The rings help align the different speeds of the gears to enable accurate and smooth gear shifting.

The synchronization system has a significant effect on the efficiency and noise generation of the gearbox. For the gearboxes to be efficient, quiet and as smooth as possible, accurate and reliable measuring systems must ensure the manufacturing quality.

The Haoneng Group

One of the world's leading manufacturers of components for the synchronization of vehicle transmissions is the Chinese Haoneng Group. The listed parent company Chengdu Haoneng Technology Co., Ltd., and its subsidiary companies together cover the entire manufacturing process of gearbox and synchronization systems. The companies are suppliers to well-known European automobile manufacturers and OEMs.

Chongqing Haoneng Xingfu Synchronizer Co., Ltd. specializes in synchronization systems for vehicles of the mid-range and luxury classes. The company had initially approached Liebherr regarding a high-quality inspection machine for the quality assurance of its products in 2014. Successful test series at the Liebherr site in Shanghai then convinced the customer to invest in a WGT 280 from Liebherr.

Lapped granite guides, air bearings, precision rotary tables and Renishaw probe systems ensure the mechanical precision of the machine. The Liebherr WGT measures any type of gear, gear-cutting tools and other rotation-symmetrical workpieces – individually configured by Liebherr according to requirements.

Each model fulfills the accuracy class of Group 1 according to VDI/VDE 2612/2613 and measures gears from a module of >0.12 mm. The software, LHInspect, enables automatic correction of setting data. It supports the manufacturer-neutral GDE interface for the exchange of geometric and measurement data between gear inspection machines and gear cutting machines and opens up the possibility of transferring further production and measurement data within the open manufacturing landscape LHOpenConnect by Liebherr.

In 2015, the subsidiary Luzhou Changjiang Machinery Co., Ltd., also invested in a Liebherr WGT. The company, founded in 1964 and the first manufacturer of synchronizer rings in China, required an inspection machine at short notice and quickly bought a WGT 280 that had been used as a demonstration machine at a trade fair in China.

The next order came three years later. This time, Luzhou Haoneng Drive Technology Co., Ltd., a manufacturer of key components for vehicle transmissions and steering systems, ordered another Liebherr WGT 280.

"We were impressed by the performance of the WGT in our sister company. This convinced us that this was precisely the inspection machine we wanted," said Jie Zhang, deputy CEO and quality manager at Haoneng in Luzhou. Finally, the parent company Chengdu Haoneng followed in 2021 with the purchase of a Liebherr WGT 400.

Production control The Liebherr WGT measures pointing for synchronizer rings and involute gear teeth, in some cases with an interrupted tooth trace, missing tooth space or missing gear tooth, as well as twisting of gears, alignment gearing with involute flanks and dedendum fillets.

The LHInspect software generates the programs for fully automatic inspection based on the workpiece data. In parallel, the results and workpiece data can be transferred between the production machine and measuring instrument via the network and read in.

After the first part has been manufactured, a control measurement takes place on the WGT which plays back the measurement results to the production machine, which in turn calculates the correction values for manufacture. After the corresponding corrections on the machine, series production can begin, which then only involves sample measurements.

Since commissioning in 2015, the system is running without disruption or standstills, said Jie Zhang, adding that the functionalities of the Liebherr WGT also fulfill the end customer's quality standards.

"The Liebherr WGT convinced us with its high accuracy and inspection quality, and in Liebherr we have found a reliable partner to whom we can turn at any time when we need support," Jie Zhang added. His company can see itself expanding its cooperation with Liebherr in the future.

"As an efficient and professional provider of holistic gearing solutions, Liebherr is a partner we can trust for the purchase of further machines, including grinding applications," said Jie Zhang.

Machining operation in which material is removed from the workpiece by a powered abrasive wheel, stone, belt, paste, sheet, compound, slurry, etc. Takes various forms: surface grinding (creates flat and/or squared surfaces); cylindrical grinding (for external cylindrical and tapered shapes, fillets, undercuts, etc.); centerless grinding; chamfering; thread and form grinding; tool and cutter grinding; offhand grinding; lapping and polishing (grinding with extremely fine grits to create ultrasmooth surfaces); honing; and disc grinding.

Strip or block of precision-ground stock used to elevate a workpiece, while keeping it parallel to the worktable, to prevent cutter/table contact.

Terms denoting a formal program for monitoring product quality. The denotations are the same, but QC typically connotes a more traditional postmachining inspection system, while QA implies a more comprehensive approach, with emphasis on "total quality," broad quality principles, statistical process control and other statistical methods.