# US 2024/0204635 A1 · Drive unit

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- Number: US 2024/0204635 A1
- Document ID: US20240204635A1
- Status: Published application
- Kind: A1
- Application number: 18/525,794
- Filed: 2023-11-30
- Published: 2024-06-20
- Earliest claimed: 2022-12-16
- Assignees: Rimac Technology LLC
- Applicants: Rimac Technology LLC
- Inventors: Dominik Padovan
- Web page: https://patentgrep.com/patent/US20240204635A1

## CPC

- H02K 7/083: {radially supporting the rotary shaft at both ends of the rotor (H02K7/086, H02K7/09 take precedence)}
- H02K 16/02: Machines with one stator and two {or more} rotors
- H02K 5/173: using bearings with rolling contact, e.g. ball bearings
- H02K 7/003: {Couplings; Details of shafts (means for mounting rotors on shafts H02K1/28)}
- H02K 7/116: with gears
- F16C 25/06: Ball or roller bearings
- F16C 2226/60: with threaded parts, e.g. bolt and nut connections
- F16C 2380/27: Motor coupled with a gear, e.g. worm gears
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})
- F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS

## Abstract

Disclosed is a drive unit. The drive unit comprises a housing, a stator, a rotor, a planetary gear set, and an interface system. The rotor comprises a rotor shaft rotatable around a rotation axis and a sun gear coupled to said rotor shaft. The planetary gear set comprises a ring gear fixed to said housing, a plurality of planet gears in meshing engagement between the sun gear and the ring gear, and a planet carrier supporting them. Furthermore, the planet carrier comprises an axial protrusion developing along the rotation axis and defining a gear shaft concentric to the rotor shaft. The interface system interfaces the rotor with the planetary gear set and comprise at least one support bearing interposed between the rotor shaft and the gear shaft.

## Claims

### Claim 1

A drive unit, comprising:
a housing;
a stator lodged inside the housing;
a rotor inserted in the housing inside the stator and comprising a rotor shaft rotatable around a rotation axis and a sun gear coupled to the rotor shaft;
a planetary gear set placed inside the housing, comprising a ring gear fixed to the housing, a plurality of planet gears in meshing engagement between the sun gear and the ring gear, and a planet carrier supporting the plurality of planet gears, the planet carrier comprising an axial protrusion developing along the rotation axis and defining a gear shaft concentric to the rotor shaft; and
an interface system configured to interface the rotor with the planetary gear set and comprising at least one support bearing interposed between the rotor shaft and the gear shaft.

### Claim 2 (depends on 1)

The drive unit according to claim 1, wherein the interface system comprises a support blocking element applied to the least one support bearing and configured to prevent axial movement of the at least one support bearing.

### Claim 3 (depends on 2)

The drive unit according to claim 2, wherein the planet carrier presents a first side and a second side, the axial protrusion developing from the first side and the planet carrier comprising an annular abutment portion developing from the second side and concentric to the rotor shaft; the interface system comprises an auxiliary bearing interposed between the rotor shaft and the annular abutment portion.

### Claim 4 (depends on 3)

The drive unit according to claim 3, wherein the interface system comprises an auxiliary blocking element applied to the auxiliary bearing and configured to prevent axial movements of the auxiliary bearing.

### Claim 5 (depends on 4)

The drive unit according to claim 4, wherein the gear shaft and/or the annular abutment portion presents on an internal surface a circumferential groove, and the support blocking element and/or the auxiliary blocking element comprise a retaining ring presenting an outer portion inserted in the groove and an inner portion in abutment with the support bearing and/or the auxiliary bearing, preventing axial movements of the planetary gear set.

### Claim 6 (depends on 3)

The drive unit according to claim 3, wherein the interface system comprises at least one pressure element coupled to the rotor shaft and configured to apply an axial load by direct contact respectively on the support bearing and/or the auxiliary bearing.

### Claim 7 (depends on 6)

The drive unit according to claim 6, wherein the least one pressure element is configured to apply an axial load on the support bearing, the axial load being transmitted to the auxiliary bearing through the planet carrier or vice versa.

### Claim 8 (depends on 7)

The drive unit according to claim 7, wherein the rotor shaft has a threaded section, and the least one pressure element presents a corresponding threaded portion screwable to the threaded section.

### Claim 9 (depends on 7)

The drive unit according to claim 7, wherein the rotor comprises a central member extending along the axis of rotation to define the rotor shaft and one extension member radially protruding from the central member in a plane perpendicular to the rotation axis (X) and separating the rotor shaft into a first portion and a second portion; the planetary gear set being coupled to the first portion so as to interface the rotor shaft with the housing.

### Claim 10 (depends on 9)

The drive unit according to claim 9, wherein the central member and the extension member define an annular seat configured to lodge at least the auxiliary bearing and at least a portion of the gear set.

### Claim 11 (depends on 10)

The drive unit according to claim 10, wherein the support bearing and/or the auxiliary bearing is a rolling bearing.

### Claim 12 (depends on 11)

The drive unit according to claim 11, wherein the support bearing and/or the auxiliary bearing each comprises an inner ring coupled to the rotor shaft and an outer ring rotatable relative to the inner ring and coupled to the gear shaft or the annular abutment portion respectively.

### Claim 13 (depends on 12)

The drive unit according to claim 12, wherein the planetary gear set is a compound planetary gear set comprising at least two stages.

### Claim 14 (depends on 13)

The drive unit according to claim 13, wherein the rotor shaft presents a toothed portion configured to define the sun gear so that the rotor shaft and the sun gear are made of a single piece.

### Claim 15 (depends on 14)

The drive unit according to claim 14, comprising an interfacing bearing interposed between the gear shaft and the housing, the interfacing bearing being concentric and axially overlapping the support bearing.

### Claim 16 (depends on 1)

The drive unit according to claim 1, wherein the housing defines a volume filled with lubricating fluid adapted to lubricate each of the stator, the rotor, the planetary gear set and the interface system.

### Claim 17

A motor, comprising:
a housing;
a first stator lodged inside the housing;
a first rotor inserted in the housing inside the first stator and comprising a first rotor shaft rotatable around a rotation axis and a first sun gear coupled to the first rotor shaft;
a first planetary gear set placed inside the housing, comprising a first ring gear fixed to the housing, a plurality of first planet gears in meshing engagement between the first sun gear and the first ring gear, and a first planet carrier supporting the plurality of first planet gears, the first planet carrier comprising an axial protrusion developing along the rotation axis and defining a first gear shaft concentric to the first rotor shaft;
a first support bearing interposed between the first rotor shaft and the first gear shaft, and a first support blocking element applied to the first support bearing and configured to prevent axial movement of the first support bearing;
a second stator lodged inside the housing;
a second rotor inserted in the housing inside the second stator and comprising a second rotor shaft rotatable around a rotation axis and a second sun gear coupled to the second rotor shaft;
a second planetary gear set placed inside the housing, comprising a second ring gear fixed to the housing, a plurality of second planet gears in meshing engagement between the second sun gear and the second ring gear, and a second planet carrier supporting the plurality of second planet gears, the second planet carrier comprising an axial protrusion developing along the rotation axis and defining a second gear shaft concentric to the second rotor shaft; and
a second support bearing interposed between the second rotor shaft and the second gear shaft, and a second support blocking element applied to the second support bearing and configured to prevent axial movement of the second support bearing;
wherein the first gear shaft is coaxial with the second gear shaft and faced outward in opposite directions.

### Claim 18 (depends on 17)

The motor according to claim 17, wherein the housing further comprises an intermediate wall dividing an internal volume of the housing in two adjacent chambers such that the first stator, the first rotor, the first planetary gear set and a first interface system being positioned within a first chamber on one side of the intermediate wall, and the second stator, the second rotor, the second planetary gear and a second interface system being positioned within second chamber on an opposite side of the intermediate wall, wherein each of the two adjacent chambers are filled with lubricating fluid.

### Claim 19 (depends on 18)

The motor according to claim 18, wherein the first rotor comprises a central member extending along the axis of rotation to define the rotor shaft and one extension member radially protruding from the central member in a plane transverse, perpendicular, to the rotation axis and separating the rotor shaft in a first portion and a second portion; the planetary gear set being coupled to the first portion so as to interface the rotor shaft with the housing, whereby the first rotor and the planetary gear set remain lodged within the first portion of the housing, and
wherein the second rotor comprises a central member extending along the axis of rotation to define the rotor shaft and one extension member radially protruding from the central member in a plane transverse perpendicular, to the rotation axis and separating the rotor shaft in a first portion and a second portion; the planetary gear set being coupled to the first portion so as to interface the rotor shaft with the housing, whereby the second rotor and the planetary gear set remain lodged within the first portion of the housing.

### Claim 20 (depends on 19)

The motor according to claim 19, further comprising interfacing bearings interposed between the respective gear shaft and the housing, the interfacing bearings being concentric and axially overlapping the respective support bearing, so that the respective the rotor shaft can be supported on the housing in turn by the support bearing, the gear shaft and the interfacing bearing.