Synchronizer rings are key components in manual, automatic and dual clutch transmissions. They help to 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 four companies manufacture in the Chengdu, Chongqing and Luzhou sites in the Central Chinese province of Sichuan and 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 measuring 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.

Highly accurate measuring machines from the WGT series

Liebherr’s WGT series boasts impressive accuracy, user-friendliness and longevity. 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 measuring machine and gear cutting machines and opens up the possibility of transferring further production and measurement data within the open manufacturing landscape LHOpenConnect by Liebherr.

Impressive in application

In 2015, the subsidiary Luzhou Changjiang Machinery Co., Ltd., also invested in a Liebherr WGT. The company, founded in 1964 and the very first manufacturer of synchronizer rings in China, required an measuring machine at short notice and quickly bought a WGT 280 which had been used as a demonstration machine at a trade fair in China. The next order came three years later: 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 measuring machine we wanted,” reports 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.

Measurement of synchronizer rings for quality  assurance
Measurement of synchronizer rings for quality assurance

Production control with the Liebherr WGT

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 on the basis of 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, says 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 measuring quality, and in Liebherr we have found a reliable partner to whom we can turn at any time when we need support,” Jie Zhang continues. His company can see itself expanding the 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,” concludes Jie Zhang.

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