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Cobra acquires the HP and HPE families of precision gearboxes from MiniGears

Cobra s.r.l., an Italian company specializing in the manufacturing of custom gearboxes and power transamssions, has announced that the HP and HPE families of precision gearboxes - formerly belonging to the Italian company MiniGear s.p.a. - are now part of Cobra’s product portfolio. This addition to the Cobra product offering was achieved by acquiring the assets of the relevant MicroGear division, in October 2004. The HP and HPE precision planetary gearboxes guarantee a maximun backlash of less than 8 and 15 arcmin respectively. They are ideally suited to work with brushless electric motors, in applications where high positioning precision is required, such as in manufacturing machines and robotics. The HP and HPE products have been popular and respected for several years now, among European users, thanks to their technical characteristics such as the ability to retain their precision over their entire lifetime, as well as their good price-to-quality ratio. Cobra is planning to further develop the application potential of the HP and HPE gearboxes, by strengthening both sales and technical support, and by adding new members to the families. With this acquisition, Cobra is pursuing the diversification of its activity by entering into a high technology market that offers a good potential for growth. In doing this, Cobra can count on over twenty years of experience in the design and manufacturing of sophisticated gearboxes.

“We believe that adding the HP and HPE families to the Cobra product offering is a very good piece of news for the current and prospective users of these precision gearboxes,” said Giorgio Scagliarini, CEO of Cobra. “The HP and HPE gearboxes play a crucial role in our diversification strategy, therefore we are planning to devote all the necessary resources to develop their potential. We plan to invest on sales, service and new models. As far as the technological aspects are concerned, we will take advantage of our strong experience in the manufacturing of sophisticated gearboxes. From now on, all the engineers that develop motion control solutions can count on an additional, qualified supplier to satisfy their need for precision gearboxes.”

The manufacturing of HP and HPE gearboxes is performed at the Cobra plant using very high precision gears. The assembly process has a crucial importance, since the guaranteed precision figure is obtained by sorting the gears and combining them based on the tolerances of the machining process.

After assembly, Cobra performs a test and a measure of noise and backlash. The backlash figure is then certified for each individual gearbox. Currently the HP and HPE gearboxes are sold a distributor in Spain (Intra Automation, based in Valencia). Cobra headquarters take care of sales for all the other countries.

Characteristics of the HP and HPE precision gearboxes

The members of the HP family of planetary gearboxes with “controlled backlash” guarantee a maximum backlash of less than 8 arcmin and offer a high torsional stiffness. Upon customer request, backlash can be further reduced to 2 arcmin for the single-stage models and 3 arcmin for the double-stage models. Maximum output torque is 1200 Nm. These products address all the applications where precise positioning is required – without any change over the entire product lifetime – coupled with dynamic response. The performances of the gearboxes in the HP family are obtained thanks to high quality materials and very high precision machining. Gears are made of case hardened steel 18NiCrMo5 UNI 7846 and undergo case hardening, quenching and tempering treatments. Cogs are ground with a DIN5 (3962-3) precision level. Input shafts are made of hardened and tempered steel 39NiCrMo3 UNI 7845, and undergo hardening and tempering treatments. Output shafts are made of spheroidal graphite cast iron GS600-3 UNI 4544 with a normalization treatment. Casings are made of spheroidal graphite cast iron GS600-3 UNI 4544 in normalized state. All gears are designed according to ANSI AGMA 2001 B88 and DIN 3990 standards, for a working life of 20,000 hours at least. The gearboxes’ efficiency is 97% for the single-stage models and 95% for the double-stage models. HP gearboxes can accept a very high input speed, up to 6000 min-1, which allows to reach high torque figures with small sized, high speed engines. The eigen frequency of the gearboxes is very high, thus avoiding resonances. A bushes system ensures an easy coupling with engine shafts in a wide range of sizes, with a friction coupling joint. All the HP models are equipped with angular contact ball bearings, P6 precision class, suited for high radial and axial loads. Products are shipped ready to use, provided with P.A.O. based synthetic oil ISO VG 220. All gears are life lubricated and maintenance-free. The HP family includes five different sizes (60, 75, 100, 140, 180), all of which come in single-stage ant two-stage versions.

Single-stage versions offer four different reduction ratios (4, 5, 7 and 10); double-stage versions offer seven different reduction ratios (16, 20, 28, 40, 50, 70 and 100). All models come in both flange versions and full input shaft versions. Gearboxes of the HPE family, , share most part of the above described characteristics and offer a slightly lower precision: maximum backlash is less than 12 arcmin for the single-stage models and less than 15 arcmin for the double-stage models. Maximum output torque is 210 Nm. The HPE family includes four sizes (50, 70, 90 and 120), with two reduction ratios in the single-stage versions (5 and 10) and three reduction ratios in the double-stage versions (25, 50 and 100).

About Cobra

Founded in1981, Cobra s.r.l. is headquartered near Bologna, Italy. Its main business is design, manufacturing and sales of custom gearboxes and custom power transmissions, which are fabricated in small quantities (10 to 3,000 units per year) according to customers specifications. Products cover the power range from 5 to 300 kW. The main application areas for Cobra custom gearboxes are mixing plants and industrial applications (57% of revenues); transmissions for special vehicles, road construction vehicles and special forklift trucks (29% of revenues); and earthmoving vehicles (13% of revenues). Cobra operates on Western European and Southern American markets, and 90% of its sales come from countries other than Italy (mainly from Germany). Since October 2004, Cobra added to this business the manufacturing of the HP and HPE precision planetary gearboxes.

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