Mobility device training unit

Abstract

The invention relates to a drive unit (1, 100) of a mobility device comprising: - an electric machine (2), - a housing comprising a first shell (6) and a second shell (7), the second shell being located between the electric machine and the first shell, - a main shaft (4, 40) housed in a space (8) delimited by the first and second shells and being capable of being rotated by means of the electric machine, - the main shaft being mounted on the second shell by means of a first bearing (15, 30, 23), wherein the first bearing is mounted without play on the second shell by means of first axial retaining means (21, 211, 212). [Figure 1]

Description

Title of the invention: Drive unit for a mobility device, in particular a vehicle

[0001] The invention relates to a drive unit of a mobility device.

[0002] A drive unit generally comprises an electric motor, a housing comprising a first shell and a second shell connected together to define a space capable of enclosing at least one main transmission shaft. The second shell cooperates with the electric machine. For example, the second shell may serve as a protective element surrounding the electric motor. Or the second shell may be mechanically connected to the stator of the electric machine. The electric motor is positioned on a first side of the second shell while the first shell is positioned on a second side of the second shell.

[0003] The main shaft is intended to be rotated by means of the electric machine. The main shaft is mounted on the second shell by means of a first bearing.

[0004] When the electrical machine is started, vibrations are generated. Some of these vibrations are reflected on the first shell, causing it to vibrate. These vibrations are sources of noise and also risk damaging the various elements located in the casing. For example, in the casing there may also be an intermediate shaft cooperating by gearing with the main shaft. In the casing there may also be a differential capable of cooperating with the intermediate shaft. Thus, when the vibrations are generated on the first shell, the main shaft, the intermediate shaft and the differential may also be affected by these various vibrations and may impair their proper functioning.

[0005] The invention aims to solve these problems and to propose a drive unit which makes it possible to reduce vibrations on the first shell.

[0006] To this end, according to one aspect of the invention, a drive unit of a mobility device, in particular of a vehicle, is proposed, comprising

[0007] - an electric machine,

[0008] - a casing comprising a first shell and a second shell, the second shell being positioned between the electric machine and the first shell,

[0009] - a main shaft housed in a space delimited by the first shell and the second shell and being able to be rotated by means of the electric machine,

[0010] - the main shaft being mounted on the second shell by means of a first bearing,

[0011] in which the first bearing is mounted without play on the second shell by means of first axial retaining means.

[0012] Such a drive unit has the advantage of avoiding vibrating the first shell as much as possible and of concentrating the vibrations at the level of the second shell, close to the electric motor.

[0013] The casing may be a gearbox casing.

[0014] According to one embodiment of the invention, the first axial retaining means are located between the first bearing and the second shell.

[0015] According to one embodiment of the invention, the first axial retaining means are formed by a circlip or a screw.

[0016] According to one embodiment of the invention, the first bearing comprises an outer ring capable of being mounted on the second shell and an inner ring capable of being mounted on the main shaft, the outer ring comprises a first peripheral groove and the second shell comprises a second peripheral groove, the outer ring and the second shell being positioned relative to each other in such a way that the circlip is housed inside the first groove and the second groove.

[0017] According to one embodiment of the invention, the first bearing comprises an outer ring capable of being mounted on the second shell and an inner ring capable of being mounted on the main shaft, the second shell comprising a stop, the circlip being positioned in abutment against the stop and against the outer ring. In one example, the circlip is positioned in axial abutment against the stop and against the outer ring.

[0018] According to one embodiment of the invention, the first bearing comprises an outer ring capable of being mounted on the second shell and an inner ring capable of being mounted on the main shaft, the screw being formed by a rod and by a screw head, the rod being screwed into the second shell in such a way that the outer ring bears against the screw head. In one example, the circlip is positioned in axial abutment against the stop and against the outer ring.

[0019] According to one embodiment of the invention, at least one elastic washer is mounted between the second shell and the outer ring and / or between the outer ring and the screw head.

[0020] In an exemplary embodiment of the invention, several elastic washers are mounted supposedly axially relative to each other.

[0021] According to one embodiment of the invention, the electrical machine comprises a rotor shaft, the rotor shaft having a first end portion which is mounted around a second end portion of the main shaft, the first bearing being positioned between the first end portion of the rotor shaft and the second shell.

[0022] According to one embodiment of the invention, the electrical machine comprises a rotor shaft, the main shaft having a third end portion which is mounted around a fourth end portion of the rotor shaft, the first bearing being positioned between the third end portion of the main shaft and the second shell.

[0023] According to one embodiment of the invention, the drive unit comprises a second bearing mounted on the first shell and arranged between the main shaft and the first shell.

[0024] According to one embodiment of the invention, the second bearing is mounted with play on the first shell.

[0025] According to one embodiment of the invention, the second bearing is a roller bearing. Such a bearing makes it possible to withstand high radial loads.

[0026] According to one embodiment of the invention, the drive unit comprises an intermediate shaft which cooperates by meshing with the main shaft, the intermediate shaft being mounted on the second shell by means of a third bearing, the third bearing is mounted without play on the second shell by means of second axial retaining means.

[0027] In one example, the third bearing is identical to the first bearing and the second axial retaining means are identical to the first axial retaining means.

[0028] According to one embodiment of the invention, the intermediate shaft is mounted on the first shell by means of a fifth bearing, the fifth bearing being a roller bearing.

[0029] According to one embodiment of the invention, the intermediate shaft is positioned on the same radial space as that of the electric motor.

[0030] According to one embodiment of the invention, the drive unit comprises a differential which cooperates by meshing with the intermediate shaft, the differential being mounted on the second shell by means of a fourth bearing, the fourth bearing being mounted without play on the second shell by means of third axial retaining means.

[0031] In one example, the fourth bearing is identical to the first bearing and the third axial retaining means are identical to the first axial retaining means.

[0032] According to one embodiment of the invention, the main shaft and the intermediate shaft cooperate by meshing via a first toothing and a second toothing respectively. The intermediate shaft and the differential cooperate by meshing via a third toothing and a fourth toothing. The first toothing, the second toothing, the third toothing and the fourth toothing can be made in such a way that when the main shaft, the intermediate shaft and the differential are meshed with each other a first axial force El is generated by the main shaft, a second axial force E2 is generated by the intermediate shaft and a third axial force E3 is generated by the differential.

[0033] According to the invention, whatever the direction of rotation of the main shaft, the different axial loads resulting from the different axial forces E1, E2 and E3 are all retransmitted directly to the second shell or indirectly via the axial retention means to the second shell.

[0034] According to one embodiment of the invention, the first toothing, the second toothing, the third toothing and the fourth toothing each have a helical shape.

[0035] According to one embodiment of the invention, the helical shape of the teeth is chosen in such a way as to compensate for the respective axial forces.

[0036] Other characteristics and advantages of the invention will emerge on reading the description which follows, with reference to the appended figures.

[0037] [Fig.l] [Fig.l] illustrates a drive unit of a vehicle, according to a first embodiment of the invention;

[0038] [Fig.2] [Fig.2] illustrates an enlargement of a mounting area of ​​a tree main on a casing of the drive unit, according to the first embodiment of the invention;

[0039] [Fig.3] [Fig.3] illustrates an enlargement of a mounting area of ​​a tree main on a casing of the drive unit, according to a second embodiment of the invention;

[0040] [Fig.4] [Fig.4] illustrates a bearing of a drive unit of a vehicle, according to a third embodiment of the invention;

[0041] [Fig.5] [Fig.5] illustrates a drive unit of a vehicle, according to a fourth embodiment of the invention.

[0042] In [Fig.l] is illustrated a drive unit 1 of a vehicle intended more particularly, although not exclusively, for a motorized personal transport device according to a first embodiment of the invention. This drive unit 1 comprises an electric motor 2, a casing 3, a main shaft 4, an intermediate shaft 5 and a differential 11. The differential 11 makes it possible to distribute the torque between two output half-shafts (not shown in [Fig.l]). The casing 3 comprises a first shell 6 and a second shell 7. The first shell 6 and the second shell 7 are fixedly connected to each other so as to delimit a space 8. The second shell 7 is connected to the electric motor 2 by a first side and is connected to the first shell 6 by a second side opposite the first side. The second shell 7 may be part of a protective cover of the electric motor 2.

[0043] The main shaft 4 is driven directly by the electric motor 2. In one example not shown, the electric motor 2 has a rotor shaft with a first end portion that is mounted around a second end portion of the main shaft 4 (not shown). Or in another example, the main shaft 4 has a third end portion that is mounted around a fourth end portion of the rotor shaft (not shown).

[0044] The intermediate shaft 5 is connected to the main shaft 4 by meshing of the main shaft 4 and the intermediate shaft 5 with each other. For this purpose, the main shaft 4 has a first toothing 9 and the intermediate shaft 5 has a second toothing 10. The main shaft 4 and the intermediate shaft 5 cooperate by meshing of the first toothing 9 and the second toothing 10 with each other.

[0045] The intermediate shaft 5 is intended to also cooperate with the differential 11. For this, the intermediate shaft 5 has a third toothing 12 and the differential 11 has a fourth toothing 13. The intermediate shaft 5 and the differential 11 cooperate with each other by meshing of the third toothing 12 and the fourth toothing 13 with each other.

[0046] The first toothing 9 and the third toothing 12 are formed directly on the main shaft 4 and on the intermediate shaft 5 respectively. While the second toothing 10 and the fourth toothing 13 are each formed by an attached toothed wheel.

[0047] According to the embodiment [Fig.l], the main shaft 4, the intermediate shaft 5 and the differential 11 are mounted on the second shell 7 by means of a first bearing 15, a second bearing 26 and a third bearing 27 respectively.

[0048] The main shaft 4, the intermediate shaft 5 and the differential 11 are also mounted on the first shell 6 by means of a fourth bearing 14, a fifth bearing 28 and a sixth bearing 29 respectively.

[0049] The first bearing 15 is intended to be positioned directly in contact with the main shaft 4. However, in a variant not illustrated as previously mentioned, when the rotor shaft is mounted on the main shaft 4, the first bearing 15 is mounted indirectly on the main shaft 4 via the rotor shaft (not illustrated).

[0050] The first bearing 15 has an outer ring 16, an inner ring 17 and balls such as 18 arranged between the outer ring 16 and the inner ring 17, [Fig.2]. The outer ring 16 is suitable for being mounted on the second shell 7. The ring internal 17 is capable of being mounted directly on the main shaft 4 or indirectly on the main shaft 4 via the rotor shaft (not shown).

[0051] The outer ring 16 has a first peripheral groove 19 and the second shell 7 has a second peripheral groove 20. The outer ring 16 and the second shell 7 are positioned relative to each other in such a way that the first peripheral groove 19 and the second peripheral groove 20 are positioned opposite each other to form a housing 22 in which a circlip 21 is inserted.

[0052] The internal ring 17 is mounted on the main shaft 4 while being axially supported against a protuberance 25. This protuberance can be, as illustrated, an outgrowth of the main shaft 4 or else an attached ring (not illustrated) or else another circlip (not illustrated).

[0053] As a variant [Fig. 3], a second embodiment is illustrated with a first bearing 30 having an outer ring 301, an inner ring 302 and balls 303 arranged between the outer ring 301 and the inner ring 302. The outer ring 301 is mounted on the second shell 7 while the inner ring 302 is mounted on the main shaft 4. A third peripheral groove 200 is formed only by the second shell 7. This peripheral groove 200 is capable of receiving a circlip 211. Thus, the outer ring 161 is positioned axially bearing by a first side directly against the second shell 7 and by a second side opposite the first side indirectly against the second shell 7 by means of the circlip 211. The circlip 211 is then wedged inside the peripheral groove 200 between the outer ring 301 and a stop 71 formed by the second shell 7.

[0054] In another variant [Fig. 4], a third embodiment of the invention is illustrated with a first bearing 23 having an outer ring 231, an inner ring 232 and balls 233 arranged between the outer ring 231 and the inner ring 232. A stop 212 is mounted on the second shell 7 and is formed by a screw equipped with a rod 213 and a screw head 214. The rod 213 is screwed to the shell 7 in such a way that the screw head 214 is placed in abutment against the outer ring 231.

[0055] Elastic washers such as 24 may be arranged between the second shell 7 and the outer ring 231 by a first side and between the outer ring 231 and the screw head 214 by a second side.

[0056] The second bearing 26 and the third bearing 27 may each be of identical configuration to one of the first bearings 15, 30 or 23 as previously described.

[0057] The fourth bearing 14 is a roller bearing. Such a bearing can withstand high radial loads.

[0058] The fifth bearing 28 and the sixth bearing 29 may each be confi- identical configuration to the fourth bearing.

[0059] [Fig. 5] illustrates a drive unit 100 of a vehicle intended more particularly, although not exclusively, for a motorized personal transport device according to a fourth embodiment of the invention. This drive unit 100 differs from that illustrated in [Fig. 1] in that it has a main shaft 40 which is supported solely on the second shell 7 by a bearing identical to the first bearing 15. This drive unit 100 also differs from that illustrated in [Fig. 1] in that the directions of the forces generated by the main shaft 4 are reversed.

[0060] In the first embodiment [Fig.l], the first toothing 9, the second toothing 10, the third toothing 12 and the fourth toothing 13 each have a helical shape. The first toothing 9 and the second toothing 10 are made in such a way that when the main shaft 4, the intermediate shaft 5 and the differential 11 are meshed with each other in a first direction of rotation of the main shaft 4, a first axial force E1 is generated by the main shaft 4, a second axial force E2 is generated by the intermediate shaft 5 and a third axial force E3 is generated by the differential 11. The first axial force E1 is directed from the second shell 7 towards the first shell 6. The second axial force E2 is directed from the first shell 6 towards the second shell 7. The third force E3 is directed from the second shell 7 towards the first shell 6.According to this first direction of rotation of the main shaft 4, the different axial loads resulting from the different axial forces E1, E2 and E3 are all retransmitted directly or indirectly by means of the circlip 21 to the second shell 7.

[0061] In the example [Fig. 5], axial forces E1', E2' and E3' equivalent to the axial forces E1, E2 and E3 are also shown. It may be noted that the drive unit 100 is configured in such a way that only the axial force E1' is reversed with respect to the axial force E1 as illustrated in [Fig. 1]. The direction of the axial force of E2' and E3' is identical to the direction of the axial force of E2 and E3. In the same way as for the example in [Fig. 1], the different axial loads resulting from the different axial forces E1', E2' and E3' are all retransmitted directly or indirectly via the circlip 21 to the second shell 7.

Claims

Claims

1. Drive unit (1,100) of a mobility device, in particular of a vehicle, comprising - an electric machine (2), - a housing comprising a first shell (6) and a second shell (7), the second shell being located between the electric machine and the first shell, - a main shaft (4,40) housed in a space (8) delimited by the first shell and the second shell and being able to be rotated by means of the electric machine, - the main shaft being mounted on the second shell by means of a first bearing (15,30,23), wherein the first bearing is mounted without play on the second shell by means of first axial retaining means (21,211, 212).

2. A drive unit according to claim 1 wherein the first axial retaining means are located between the first bearing and the second shell.

3. Drive unit according to claim 1 or 2, wherein the first axial retaining means are formed by a circlip (21,211) or a screw (212).

4. A drive unit according to claim 3, wherein the first bearing comprises an outer ring (16) adapted to be mounted on the second shell and an inner ring (17) adapted to be mounted on the main shaft, the outer ring comprises a first peripheral groove (19) and the second shell comprises a second peripheral groove (20), the outer ring and the second shell being positioned relative to each other in such a way that the circlip (21) is housed inside the first groove and the second groove.

5. Drive unit according to claim 3, in which the first bearing comprises an outer ring (301) capable of being mounted on the second shell and an inner ring (302) capable of being mounted on the main shaft, the second shell comprising a stop (71), the circlip (211) being positioned in abutment against the stop and against the outer ring.

6. A drive unit according to claim 3, wherein the first bearing comprises an outer ring (231) adapted to be mounted on the second shell and an internal ring (232) capable of being mounted on the main shaft, the screw being formed by a rod (213) and by a screw head (214), the rod being screwed into the second shell so that the external ring bears against the screw head.

7. Drive unit according to claim 6, wherein at least one elastic washer (24) is mounted between the second shell and the outer ring and / or between the outer ring and the screw head.

8. Drive unit according to one of claims 1 to 7, in which it comprises a second bearing (14) mounted on the first shell and arranged between the main shaft and the first shell.

9. A drive unit according to claim 8, wherein the second bearing is a roller bearing.

10. A drive unit according to claim 9, wherein the second bearing (14) is mounted with play on the first shell.

11. Drive unit according to one of claims 1 to 10, in which it comprises an intermediate shaft (5) which cooperates by meshing with the main shaft, the intermediate shaft being mounted on the second shell by means of a third bearing (26), the third bearing is mounted without play on the second shell by means of second axial retaining means (21,211,212).

12. A drive unit according to claim 11, wherein the intermediate shaft is mounted on the first shell via a fifth bearing (28), the fifth bearing being a roller bearing.

13. A drive unit according to claim 11 or claim 12, wherein the intermediate shaft is positioned on the same radial footprint as that of the electric motor.

14. Drive unit according to claim 12 or 13, in which it comprises a differential (11) which cooperates by meshing with the intermediate shaft, the differential being mounted on the second shell by means of a fourth bearing (27), the fourth bearing being mounted without play on the second shell by means of third axial retaining means (21,211,212).

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