Tesla has been granted a patent for an electric drive unit and method of assembly. The unit includes a rotor shaft and gear shaft, with the rotor shaft inserted into the gear shaft. The gear shaft is supported by two bearings, while the rotor shaft is supported directly by one bearing and indirectly by the gear shaft. The patent also discloses a wave spring for axial loading, a balancing ring for rotor balance, and a spline connection between the rotor and gear shafts. The method of assembly involves positioning the different sections of the rotor and gear shafts into the corresponding bearings. The unit is designed to have only three bearings in the rotor and gear shaft portion. GlobalData’s report on Tesla gives a 360-degree view of the company including its patenting strategy. Buy the report here.

According to GlobalData’s company profile on Tesla,battery management systems was a key innovation area identified from patents. Tesla's grant share as of June 2023 was 1%. Grant share is based on the ratio of number of grants to total number of patents.

Electric drive unit assembly with three bearings

Source: United States Patent and Trademark Office (USPTO). Credit: Tesla Inc

A recently granted patent (Publication Number: US11686384B2) describes a method for assembling an electric drive unit with only three bearings in the rotor shaft and gear shaft portion. The method involves several steps, including providing a rotor shaft and a gear shaft, positioning different regions of the shafts into the bearings, and forming a spline connection between the rotor shaft and gear shaft.

The first claim of the patent outlines the main steps of the method, which include positioning the rotor shaft and gear shaft into the bearings in a specific arrangement. The third bearing supports both the rotor shaft and gear shaft, and the entire rotor shaft and gear shaft portion consists of only three bearings.

Additional claims provide further details and variations of the method. For example, claim 2 mentions the presence of a pilot journal in the rotor shaft and a pilot bore in the gear shaft, which are brought into contact with each other. Claim 4 describes the use of spline connectors in the rotor shaft and gear shaft to form a spline connection.

The patent also includes claims related to the use of a balancing ring in the electric drive unit. Claim 8 explains the positioning of a portion of the rotor shaft through the balancing ring and securing it with a lock nut. The balancing ring functions as a Belleville-type spring when loaded against the lock nut and the first rotor end.

Other claims discuss the use of a wave spring for axial preloading of the first bearing, the presence of laminated discs in the electric drive unit, and the machining and balancing of the balancing ring.

Overall, this granted patent presents a method for assembling an electric drive unit with a specific arrangement of bearings in the rotor shaft and gear shaft portion. The method includes various steps and features, such as spline connections, balancing rings, and wave springs, to ensure the proper functioning of the electric drive unit.

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GlobalData, the leading provider of industry intelligence, provided the underlying data, research, and analysis used to produce this article.

GlobalData Patent Analytics tracks bibliographic data, legal events data, point in time patent ownerships, and backward and forward citations from global patenting offices. Textual analysis and official patent classifications are used to group patents into key thematic areas and link them to specific companies across the world’s largest industries.