Drive unit of mobile device, in particular of vehicle

Abstract

The invention relates to a drive unit (1, 100) of a mobile device, comprising:-a motor (2),-a housing comprising a first housing (6) and a second housing (7), the second housing being located between the motor and the first housing,-a main shaft (4, 40) housed in a space (8) delimited by the first and second housings and rotatable by the motor,-the main shaft (4, 40) being driven by a first rolling bearing (15, 30, 40), according to the invention, the first rolling bearing is mounted on the second housing by means of a first axial retaining device (21, 211, 212) without play on the second housing.

Description

Technical Field

[0001] The invention relates to a driving unit of a mobile device. Background Art

[0002] The drive unit generally comprises an electric motor, a housing comprising a first shell and a second shell, the first shell and the second shell being connected to each other to define a space that can accommodate at least a main transmission shaft. The second shell cooperates with the motor. For example, the second shell can be used as a protective element around the motor. Alternatively, the second shell can be mechanically connected to the stator of the motor. The motor is positioned on a first side of the second shell, and the first shell is positioned on a second side of the second shell.

[0003] The main shaft is intended to be rotated by the motor and is mounted on the second housing via a first rolling bearing.

[0004] When the motor is started, vibrations are generated. Some of these vibrations vibrate on the first shell, causing the first shell to vibrate. These vibrations are a source of noise and there is also a risk of damaging various components located in the shell. For example, an intermediate shaft that cooperates with the main shaft through gear transmission may also be located in the shell. The differential that can cooperate with the intermediate shaft may also be located in the shell. Therefore, when 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 their normal operation may be impaired. Summary of the invention

[0005] The present invention aims to solve these problems and proposes a driving unit capable of reducing vibration on a first housing.

[0006] To this end, according to one aspect of the present invention, a driving unit of a mobile device, in particular a vehicle, is proposed, the driving unit comprising:

[0007] - Motor,

[0008] - a housing comprising a first shell and a second shell, the second shell being positioned between the motor and the first shell,

[0009] - a main shaft housed in the space defined by the first shell and the second shell and capable of being rotated by the motor,

[0010] - the main shaft is mounted on the second housing via a first rolling bearing,

[0011] The first rolling bearing is mounted on the second shell without clearance through the first axial retaining device.

[0012] Such a drive unit has the advantage of avoiding vibrations of the first housing as much as possible and concentrating the vibrations on the second housing close to the electric motor.

[0013] The housing may be a gearbox housing.

[0014] The first rolling bearing is, for example, a ball bearing.

[0015] According to one embodiment of the invention, the first axial retaining means is located between the first rolling bearing and the second shell.

[0016] According to one embodiment of the invention, the first axial retaining means is formed by a circlip or a screw.

[0017] According to one embodiment of the invention, the first rolling bearing has an outer ring that can be mounted on the second shell and an inner ring that can be mounted on the main shaft, the outer ring having a first peripheral groove and the second shell having a second peripheral groove, the outer ring and the second shell being positioned relative to each other in such a way that the elastic ring is accommodated in the first groove and the second groove.

[0018] According to one embodiment of the invention, the first rolling bearing has an outer ring that can be mounted on the second shell and an inner ring that can be mounted on the main shaft, the second shell has a stopper, and the circlip is positioned to bear against the stopper and against the outer ring. In one example, the circlip is positioned to bear axially against the stopper and against the outer ring.

[0019] According to one embodiment of the invention, the first rolling bearing has an outer ring that can be mounted on the second shell and an inner ring that can be mounted on the spindle, the screw being formed by a rod and a screw head, the rod being screwed into the second shell so that the outer ring bears against the screw head. In one example, a plate is axially inserted between the screw head and the outer ring.

[0020] According to one embodiment of the invention, at least one elastic washer is installed between the second shell and the outer ring and / or between the outer ring and the screw head.

[0021] In an exemplary embodiment of the invention, several elastic washers are mounted axially superposed relative to each other.

[0022] According to one embodiment of the invention, the electric machine has a rotor shaft having a first end mounted around a second end of the main shaft, and a first rolling bearing is positioned between the first end of the rotor shaft and the second shell.

[0023] According to one embodiment of the invention, the electric machine has a rotor shaft, the main shaft has a third end mounted around a fourth end of the rotor shaft, and the first rolling bearing is positioned between the third end of the main shaft and the second shell.

[0024] According to one embodiment of the invention, the drive unit has a second rolling bearing mounted on the first housing and arranged between the main shaft and the first housing.

[0025] According to one embodiment of the present invention, the second rolling bearing is mounted on the first shell with clearance. The second rolling bearing is mounted on the first shell with clearance in the axial direction to prevent vibration from being transmitted in the first shell.

[0026] According to one embodiment of the present invention, the second rolling bearing is a roller bearing. Such a rolling bearing bears a large radial load.

[0027] According to one embodiment of the invention, the drive unit has an intermediate shaft cooperating with the main shaft by meshing, the intermediate shaft being mounted on the second housing via a third rolling bearing, the third rolling bearing being mounted on the second housing without play via a second axial retaining device.

[0028] In one example, the third rolling bearing is identical to the first rolling bearing and the second axial retaining means is identical to the first axial retaining means.

[0029] According to one embodiment of the invention, the intermediate shaft is mounted on the first housing via a fifth rolling bearing, which is a roller bearing.

[0030] According to one embodiment of the present invention, the fifth rolling bearing is mounted on the first shell with clearance in the axial direction. The fifth rolling bearing is mounted on the first shell with clearance in the axial direction to prevent vibration from being transmitted in the first shell.

[0031] According to one embodiment of the invention, the intermediate shaft is positioned in the same radial footprint as the radial footprint of the electric machine.

[0032] According to one embodiment of the invention, the electric machine exhibits a substantially cylindrical footprint, which is defined in particular by its outer diameter, the axis of rotation of the intermediate shaft being inscribed within the outer diameter of the electric machine.

[0033] Advantageously, the electric machine can be axially supported on the second housing by means of a substantially circular bearing surface having an outer diameter, the axis of rotation of the intermediate shaft being inscribed in the outer diameter of the bearing surface. In this way, the electric machine participates in the rigidification of the second housing. The reaction of the axial forces in the main shaft and the intermediate shaft acts on the rigidified region of the second housing.

[0034] In a variant, the second shell can directly support the electric machine by means of a support ring formed integrally with the second shell, into which the electric machine is inserted. In this way, the reaction of the axial forces in the main shaft and the intermediate shaft acts on the rigidified zone of the second shell.

[0035] According to one embodiment of the invention, the first axial retaining means and the second axial retaining means are common and formed by the same stopper, thereby facilitating the assembly of the drive unit.

[0036] According to one embodiment of the invention, the first axial retaining means and the second axial retaining means are axially offset and supported by the same stopper.

[0037] Preferably, the stop may comprise a common plate provided with two apertures arranged for the passage of the main shaft and the intermediate shaft.

[0038] According to one embodiment of the invention, the drive unit has a differential cooperating with the intermediate shaft by meshing, the differential being mounted on the second housing via a fourth rolling bearing, the fourth rolling bearing being mounted on the second housing without play via a third axial retaining device.

[0039] In one example, the fourth rolling bearing is identical to the first rolling bearing and the third axial retaining means is identical to the first axial retaining means.

[0040] According to one embodiment of the present invention, the main shaft and the intermediate shaft cooperate by meshing the first and second teeth, respectively. The intermediate shaft and the differential cooperate by meshing the third and fourth teeth, respectively. The first, second, third and fourth teeth may be formed such that, when the main shaft, the intermediate shaft and the differential are meshed with each other, the main shaft generates a first axial force E1, the intermediate shaft generates a second axial force E2, and the differential generates a third axial force E3.

[0041] According to the present invention, regardless of the rotation direction of the main shaft, the different axial loads generated by the different axial forces E1, E2 and E3 are all directly transmitted to the second housing or indirectly transmitted to the second housing through the axial retaining device.

[0042] According to one embodiment of the invention, the first tooth, the second tooth, the third tooth and the fourth tooth each have a spiral form.

[0043] According to one embodiment of the invention, the helical form of the teeth is selected to compensate for corresponding axial forces. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Further features and advantages of the present invention will become apparent from reading the following description with reference to the accompanying drawings.

[0045] Figure 1 A drive unit for a vehicle according to a first embodiment of the present invention is shown;

[0046] Figure 2 An enlarged view showing a mounting area of ​​a spindle on a housing of a drive unit according to a first embodiment of the present invention;

[0047] Figure 3 An enlarged view showing a mounting area of ​​a spindle on a housing of a drive unit according to a second embodiment of the present invention;

[0048] Figure 4 A rolling bearing of a drive unit of a vehicle according to a third embodiment of the present invention is shown;

[0049] Figure 5 A drive unit for a vehicle according to a fourth embodiment of the present invention is shown;

[0050] Figure 6 A drive unit for a vehicle according to a fifth embodiment of the present invention is shown. DETAILED DESCRIPTION

[0051] Figure 1 A drive unit 1 for a vehicle according to a first embodiment of the invention is shown, the vehicle being more particularly, but not exclusively, intended for use as a personal transporter. The drive unit 1 has an electric machine 2, a housing 3, a main shaft 4, an intermediate shaft 5 and a differential 11. The differential 11 is provided between two output half shafts ( Figure 1 The housing 3 has a first shell 6 and a second shell 7. The first shell 6 and the second shell 7 are fixedly connected to each other to define a space 8. The second shell 7 is connected to the motor 2 on a first side and to the first shell 6 on a second side opposite to the first side. The second shell 7 may be part of a protective cover for the motor 2.

[0052] The main shaft 4 is directly driven by the motor 2. In one example, not shown, the motor 2 has a rotor shaft having a first end mounted around a second end (not shown) of the main shaft 4. Alternatively, in another example, the main shaft 4 has a third end mounted around a fourth end (not shown) of the rotor shaft.

[0053] The intermediate shaft 5 is connected to the main shaft 4 by the mutual meshing of the main shaft 4 and the intermediate shaft 5. For this purpose, the main shaft 4 has first teeth 9 and the intermediate shaft 5 has second teeth 10. The main shaft 4 and the intermediate shaft 5 cooperate by the mutual meshing of the first teeth 9 and the second teeth 10.

[0054] The intermediate shaft 5 is intended to cooperate also with a differential 11. To this end, the intermediate shaft 5 has third teeth 12 and the differential 11 has fourth teeth 13. The intermediate shaft 5 and the differential 11 cooperate with each other by the third teeth 12 and the fourth teeth 13 meshing with each other.

[0055] The first teeth 9 and the third teeth 12 are respectively formed directly on the main shaft 4 and the intermediate shaft 5. Whereas the second teeth 10 and the fourth teeth 13 are each formed by an attached toothed wheel.

[0056] according to Figure 1 In the exemplary embodiment of FIG. 4 , the main shaft 4 , the intermediate shaft 5 and the differential 11 are mounted on the second housing 7 via a first rolling bearing 15 , a second rolling bearing 26 and a third rolling bearing 27 , respectively.

[0057] The main shaft 4 , the intermediate shaft 5 and the differential 11 are also mounted on the first housing 6 via a fourth rolling bearing 14 , a fifth rolling bearing 28 and a sixth rolling bearing 29 , respectively.

[0058] The first rolling bearing 15 is intended to be positioned in direct contact with the main shaft 4. However, in a variant not shown, as described above, when the rotor shaft is mounted on the main shaft 4, the first rolling bearing 15 is indirectly mounted on the main shaft 4 via the rotor shaft (not shown).

[0059] The first rolling bearing 15 has an outer ring 16, an inner ring 17, and a ball (for example, 18) disposed between the outer ring 16 and the inner ring 17 ( Figure 2 ). The outer ring 16 can be mounted on the second shell 7. The inner ring 17 can be mounted directly on the main shaft 4 or indirectly on the main shaft 4 through a rotor shaft (not shown).

[0060] 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 facing each other to form a housing 22 into which the circlip 21 is inserted.

[0061] The inner ring 17 is mounted on the main shaft 4 while bearing axially against a projection 25. As shown, this projection may be a protrusion of the main shaft 4, or an attachment ring (not shown) or another circlip (not shown).

[0062] exist Figure 3 In a variant of the embodiment of the present invention, a second embodiment is shown, which has a first rolling bearing 30 with an outer ring 301, an inner ring 302 and a ball 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. The third peripheral groove 200 is formed only by the second shell 7. This peripheral groove 200 can receive a circlip 211. Therefore, the outer ring 161 is positioned to bear directly against the second shell 7 on a first side in the axial direction and indirectly against the second shell 7 via the circlip 211 on a second side opposite to the first side. The circlip 211 is then wedged in the peripheral groove 200 between the outer ring 301 and the stop 71 formed by the second shell 7.

[0063] exist Figure 4 In another variant, a third embodiment of the invention is shown, which has a first rolling bearing 23 with an outer ring 231, an inner ring 232 and a ball 233 arranged between the outer ring 231 and the inner ring 232. The 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 to bear against the outer ring 231.

[0064] An elastic gasket (such as 24 ) may be disposed between the second shell 7 and the outer ring 231 on a first side, and between the outer ring 231 and the screw head 214 on a second side.

[0065] The second rolling bearing 26 and the third rolling bearing 27 may each have the same configuration as one of the first rolling bearings 15 , 30 or 23 described above.

[0066] The 4th rolling bearing 14 is a roller bearing. This rolling bearing bears a very large radial load.

[0067] The fifth rolling bearing 28 and the sixth rolling bearing 29 may each have the same configuration as the fourth rolling bearing.

[0068] Figure 5 A drive unit 100 for a vehicle according to a fourth embodiment of the invention is shown, the vehicle being more particularly, but not exclusively, intended for use as a personal transport vehicle. Figure 1 The drive unit shown in FIG. 1 is different in that it has a main shaft 40 which is supported only on the second shell 7 via a rolling bearing identical to the first rolling bearing 15. Figure 1 The drive unit shown in FIG. 1 also differs in that the direction of the force generated by the spindle 4 is reversed.

[0069] exist Figure 1 In the first embodiment of the present invention, the first teeth 9, the second teeth 10, the third teeth 12 and the fourth teeth 13 each have a spiral form. The first teeth 9 and the second teeth 10 are formed so that when the main shaft 4, the intermediate shaft 5 and the differential 11 are engaged with each other in the first rotation direction of the main shaft 4, the main shaft 4 generates a first axial force E1, the intermediate shaft 5 generates a second axial force E2, and the differential 11 generates a third axial force E3. The first axial force E1 is directed from the second shell 7 to the first shell 6. The second axial force E2 is directed from the first shell 6 to the second shell 7. The third force E3 is directed from the second shell 7 to the first shell 6. In the first rotation direction of the main shaft 4, the different axial loads generated by the different axial forces E1, E2 and E3 are all transmitted to the second shell 7 directly or indirectly through the circlip 21.

[0070] exist Figure 5 In the example of FIG. 1 , axial forces E1′, E2′ and E3′ equivalent to the axial forces E1, E2 and E3 are also shown. It can be noted that the drive unit 100 is configured so that only the axial force E1′ is relative to the axial force E1′. Figure 1 The axial forces E2' and E3' are in the same direction as the axial forces E2 and E3. Figure 1 In the same manner as in the example in FIG. 2 , the different axial loads generated by the different axial forces E1 ′, E2 ′ and E3 ′ are all transmitted to the second shell 7 directly or indirectly through the circlip 21 .

[0071] Figure 6 A drive unit for a motorized vehicle according to a fifth embodiment of the invention is shown. Figure 1 The drive unit shown in FIG. 2 differs in that it has a first axial retaining means and a second axial retaining means which are formed in common by the same stop 212 .

[0072] In this example, the first and second axial retaining means are axially offset and supported by a common stop 212. The stop 212 comprises a common plate 215 provided with two orifices arranged for the passage of the main shaft 4 and the intermediate shaft 5.

[0073] The stopper 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 is screwed to the second shell 7 in such a way that the screw head 214 is placed bearing against a common plate 215.

[0074] In this example, the electric machine 2 presents a substantially cylindrical footprint, which is defined in particular by its outer diameter d, in which the axis of rotation of the intermediate shaft 5 is inscribed. Furthermore, the electric machine is axially supported on the second housing 7 by means of a substantially circular bearing surface 2a having an outer diameter d, in which the axis of rotation of the intermediate shaft 5 is inscribed.

Claims

1. A drive unit (1, 100) for a mobile device, in particular a vehicle, comprising: - an electric motor (2), - a housing, the housing comprising a first housing (6) and a second housing (7), the second housing being located between the motor and the first housing, a main shaft (4, 40) housed in a space (8) defined by the first shell and the second shell and capable of being moved in rotation by the motor, - the main shaft is mounted on the second housing via a first rolling bearing (15, 30, 23), The first rolling bearing is installed on the second shell without gap through a first axial retaining device (21, 211, 212).

2. The drive unit according to claim 1, wherein: The first axial retaining device is located between the first rolling bearing and the second shell.

3. The drive unit according to claim 1 or 2, wherein: The first axial retaining device is formed by an elastic retaining ring (21, 211) or a screw (212).

4. The drive unit according to claim 3, wherein: The first rolling bearing has an outer ring (16) that can be mounted on the second shell and an inner ring (17) that can be mounted on the main shaft, the outer ring having a first peripheral groove (19) and the second shell having a second peripheral groove (20), the outer ring and the second shell being positioned relative to each other in such a way that the elastic ring (21) is accommodated in the first groove and the second groove.

5. The drive unit according to claim 3, wherein: The first rolling bearing has an outer ring (301) that can be mounted on the second shell and an inner ring (302) that can be mounted on the main shaft, the second shell has a stopper (71), and the elastic ring (211) is positioned to bear against the stopper and against the outer ring.

6. The drive unit according to claim 3, wherein: The first rolling bearing has an outer ring (231) that can be mounted on the second shell and an inner ring (232) that can be mounted on the spindle, the screw being formed by a rod (213) and a screw head (214), the rod being screwed into the second shell so that the outer ring bears against the screw head.

7. The drive unit according to claim 6, wherein: At least one elastic washer (24) is installed between the second shell and the outer ring and / or between the outer ring and the screw head.

8. The drive unit according to any one of claims 1 to 7, wherein: The drive unit has a second rolling bearing (14) mounted on the first housing and arranged between the main shaft and the first housing.

9. The drive unit according to claim 8, wherein: The second rolling bearing is a roller bearing.

10. The drive unit according to claim 9, wherein: The second rolling bearing (14) is mounted on the first shell with clearance.

11. The drive unit according to any one of claims 1 to 10, wherein: The drive unit has an intermediate shaft (5) cooperating with the main shaft by meshing, the intermediate shaft being mounted on the second housing via a third rolling bearing (26), the third rolling bearing being mounted on the second housing without play via a second axial retaining device (21, 211, 212).

12. The drive unit according to claim 11, wherein: The intermediate shaft is mounted on the first housing via a fifth rolling bearing (28), which is a roller bearing.

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

14. The drive unit according to claim 12 or 13, wherein: The drive unit has a differential (11) cooperating with the intermediate shaft by meshing, the differential being mounted on the second housing via a fourth rolling bearing (27), the fourth rolling bearing being mounted on the second housing without play via a third axial retaining device (21, 211, 212).

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