Torque transmission assembly for mobile device

Abstract

The invention relates to a transmission assembly (100) for a mobile device, said assembly comprising: a motor comprising a rotor shaft (103); a reduction gear (104) comprising at least one driveshaft (106) for direct or indirect cooperation with the rotor shaft to transmit motor torque; and a vibration damping device (105) for reducing vibrations, the rotor shaft or the transmission shaft forming a hollow shaft defining a cavity (111) into which the damping device is inserted.

Description

Technical Field

[0001] The present invention relates to a torque transmission assembly for a mobile device, such as a motor vehicle, which is equipped with an electric motor.

[0002] The present invention relates to a transmission assembly, which includes a reduction gear receiving a torque provided by a rotor of a motor. Background Art

[0003] Document DE10017396 describes a transmission assembly comprising an electric motor with a stator and a rotor. The motor is rotationally connected to a transmission shaft via the rotor. To reduce the effects of rotor vibrations on the transmission assembly, an elastic element is inserted between the rotor and the gearbox input shaft. However, the presence of this elastic element is not entirely satisfactory and does not prevent displacement of the motor, which can lead to bending of the transmission assembly. Summary of the Invention

[0004] The present invention aims to provide a transmission assembly for mobile equipment that solves the above problems.

[0005] To this end, the subject of the invention is a transmission assembly for a mobile device, said assembly comprising:

[0006] an electric motor comprising a rotor shaft;

[0007] a reduction gear comprising at least one transmission shaft capable of cooperating directly or indirectly with the rotor shaft in order to transmit a driving torque;

[0008] a vibration damping device capable of reducing vibrations;

[0009] The rotor shaft or the transmission shaft forms a hollow shaft which delimits a housing, into which the damping device is inserted.

[0010] According to an embodiment of the invention, the damping device is tuned such that its rotation frequency is 20 to 30 times the rotation frequency of the rotor shaft.

[0011] The stiffness of the spring element is calculated in such a way that the mass does not touch the wall of the housing.

[0012] According to one embodiment, the damping device comprises a mass and a spring element, which is positioned so as to be rotationally fixed to the rotor shaft or the transmission shaft at one end and to cooperate with the mass at the other end. The damping device thus advantageously forms an inertial mass damper. The mass is designed so that, even in operation, it does not contact the inner wall defining the housing.

[0013] According to one embodiment, the spring element is formed as a rod extending along the elongation axis (X) of the rotor shaft or the transmission shaft, the rod comprising a first end fixedly mountable on the rotor shaft or the transmission shaft and a second end connectable to the mass. The rod may be made of an elastic material having a predetermined stiffness.

[0014] According to one embodiment, the spring element is arranged around the rotor shaft or the transmission shaft between the rotor shaft or the transmission shaft and the mass.

[0015] According to one embodiment, the spring element is formed as a corrugated ring, which is arranged in an annular groove formed by the inner wall of the housing. In particular, the spring element is formed as a corrugated ring, which is arranged circumferentially relative to the drive shaft or the rotor shaft. The annular groove is formed in such a way that the corrugated ring partially protrudes from the same groove.

[0016] In another example, a plurality of corrugated rings distributed along the wall defining the housing can be provided. For this purpose, the same number of annular grooves can be provided.

[0017] According to one embodiment, the spring element forms at least one corrugated sheet arranged between the rotor shaft or the transmission shaft and the mass.

[0018] According to one embodiment, the spring element forms a corrugated sheet.

[0019] According to one embodiment, the corrugated sheet forms a tube, the wall of which is formed by the longitudinal corrugations.

[0020] According to one embodiment, the longitudinal corrugated portions of the corrugated sheet are each arranged in a corresponding longitudinal groove formed by the inner wall of the housing.The longitudinal grooves are made in such a way that the longitudinal corrugated portions partially protrude from the same groove.

[0021] According to one embodiment, the corrugated sheets are arranged longitudinally with respect to the rotor shaft or the drive shaft.

[0022] According to one embodiment, the housing is closed via a closing mechanism.

[0023] According to one embodiment, the housing is sealed. An adhesive or an element made of an elastomeric material may be inserted between the rotor shaft or the transmission shaft and the closing mechanism.

[0024] According to one embodiment, the closing mechanism is a plug mounted on the rotor shaft or the transmission shaft by press-fitting, or by screwing, or by adhesive bonding on the rotor shaft or the transmission shaft.

[0025] According to one embodiment, the mass is configured in such a way that it defines two resonance modes, wherein a first resonance mode is generated by radial displacement of the mass and a second resonance mode is generated by tilting the mass about its center of gravity. In one example, the mass forms a parallelepiped structure with a square or rectangular longitudinal cross-section.

[0026] By convention, a "radial" orientation is oriented orthogonal to an axial orientation. Depending on the context, the axial orientation relates to the axis of rotation of the shaft of the rotor and / or the axis of rotation of the transmission shaft. A "circumferential" orientation is oriented orthogonal to the axial direction and orthogonal to the radial direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The invention will be better understood by reading the following description and examining the accompanying drawings, which are provided by way of complete, non-limiting illustration only.

[0028] Figure 1 is a schematic representation of a transmission assembly according to a first example of the present invention;

[0029] Figure 2A is a schematic representation of a transmission assembly according to a second example of the present invention;

[0030] Figure 2B is a schematic representation of a spring element according to a second example of the present invention, and

[0031] Figure 3 is a schematic representation of a transmission assembly according to a third example of the present invention. DETAILED DESCRIPTION

[0032] Figure 1 A transmission assembly 100 for a hybrid or electric motor vehicle is shown. Transmission assembly 100 includes an electric motor 102, which includes a rotor shaft 103, a reduction gear 104, and a vibration damping device 105 capable of reducing vibrations. Reduction gear 104 includes a first transmission shaft 106, which directly cooperates with rotor shaft 103 to transmit drive torque. Reduction gear 104 also includes a second transmission shaft 107 that cooperates with first transmission shaft 106. To this end, first transmission shaft 106 and second transmission shaft 107 include teeth 108 and 109, respectively, which are designed to cooperate with each other and allow first transmission shaft 106 to be rotationally coupled to second transmission shaft 107.

[0033] The transmission shaft 106 has an end 110 designed to cooperate with the rotor shaft 103. A housing 111 is formed at this end 110. This housing 111 is longitudinally hollowed relative to the rotational axis, or axis of elongation X, of the first transmission shaft 106. This axis of elongation X is coaxial with the other rotational axis of the rotor shaft, or axis of elongation X′ of the rotor shaft 103. Housing 111 is bounded by a wall 112 of the first transmission shaft 106. According to the present invention, the vibration damping device 105 is inserted into housing 111.

[0034] In particular, according to this first example, the damping device 105 includes a mass 113 and a rod 114. The rod 114 extends along the elongation axis X of the first transmission shaft 106. The rod 114 includes a first end 115 and a second end 116. The rod 114 is fixedly mounted on the first transmission shaft 106 via its first end 115. The mass 113 is fixed to the rod 114 via the second end 116. The rod 114 comprises an elastic material, thereby enabling the mass 113 to tilt radially relative to the elongation axis X under the influence of vibration.

[0035] The housing 111 is closed by a closing mechanism 117. The closing mechanism may be an insert 117 which is fixedly mounted by being screwed onto the end 110 of the first transmission shaft 106 by means of screws such as 118.

[0036] A sealing mechanism (not shown) may be added between the closing mechanism and the first transmission shaft 106 to prevent dust or fluid from entering the housing 111 .

[0037] Other closure mechanisms may be provided, such as a plug (not shown) that is force-fitted into the first drive shaft 106 .

[0038] Figure 2A and Figure 2B A second exemplary embodiment of the present invention is shown. In this example, a transmission assembly 200 is partially shown, which includes a transmission shaft 206, a housing 211 defined by a wall 212, and a vibration damping device 205 ( Figure 2A The damping device 205 comprises a mass block 213 and a spring element 214. The mass block 213 forms a parallelepiped structure with a square longitudinal cross section. The spring element 214 is formed by at least one corrugated ring 214 ( Figure 2B). This bellows ring 214 is arranged circumferentially around the drive shaft 206 along the wall 212 of the housing 211. To hold the bellows ring 214 axially in position inside the housing 211, an annular groove 219 made in the thickness of the wall 212 can advantageously be provided. The mass 213 is placed in the housing 211 and held in position by elastically bearing against the bellows ring 214. The mass 213 is positioned inside the housing 211 in such a way that it does not contact the wall 212. The housing 211 is closed by an insert 217, for example, by means of screws (such as 218).

[0039] Figure 3 A third exemplary embodiment of the present invention is shown. In this example, a transmission assembly 300 is partially illustrated, comprising a vibration damping device 305. The damping device 305 comprises a corrugated sheet 314 and a mass 313. The corrugated sheet 314 forms a tube whose wall is formed by longitudinal corrugations. The corrugated sheet 314 is arranged longitudinally along the wall 312 of the housing 311. To secure the corrugated sheet 314 axially in position within the housing 311, it may be advantageous to position a circlip (not shown) at the inlet of the housing 311. To secure the corrugated sheet 314 circumferentially in position within the housing 311, longitudinal grooves 319 may be provided. The corrugated sheet 314 is thus inserted through the housing 311 in such a way that the corrugated portions (not shown) of the corrugated sheet 314 are inserted into these same grooves.

[0040] The mass 313 is placed in the housing 311 while being held in place by elastic radial bearing against the corrugated sheets 314 .

[0041] The mass block 313 forms a parallelepiped structure having a rectangular longitudinal cross-section.

[0042] The housing 311 is closed by an insert 317 similar to the other two inserts 117 and 217 by means of screws such as 318 .

[0043] The mass 313 is positioned inside the housing 311 in such a way that it does not contact the wall 312 or the insert 317 .

Claims

1. A transmission assembly (100, 200, 300) for a mobile device, the assembly comprising: An electric motor, the electric motor comprising a rotor shaft (103); a reduction gear (104, 204, 304), the reduction gear comprising at least one transmission shaft (106, 206, 306), the at least one transmission shaft being capable of cooperating directly or indirectly with the rotor shaft in order to transmit a driving torque; A vibration damping device (105, 205, 305) capable of reducing vibrations, wherein the rotor shaft or the transmission shaft forms a hollow shaft defining a housing (111, 211, 311), and the damping device is inserted into the housing.

2. The transmission assembly according to claim 1, wherein: The damping device comprises a mass (113, 213, 313) and a spring element (114, 214, 314) positioned rotationally fixed to the rotor shaft or the transmission shaft at one end and cooperating with the mass at the other end.

3. The transmission assembly according to claim 2, wherein: The spring element forms a rod (114) extending along the elongation axis (X) of the rotor shaft or the transmission shaft, the rod comprising a first end (115) fixedly mountable on the rotor shaft or the transmission shaft and a second end (116) connectable to the mass.

4. The transmission assembly according to claim 2, wherein: The spring element is arranged around the rotor shaft or the transmission shaft between the rotor shaft or the transmission shaft and the mass.

5. The transmission assembly according to claim 4, wherein: The spring element forms a corrugated ring which is arranged in an annular groove (219) formed by the inner wall (212) of the housing.

6. The transmission assembly according to claim 4, wherein: The spring elements form a corrugated sheet which forms a tube whose wall is formed by the longitudinal corrugations.

7. The transmission assembly according to claim 6, wherein: The longitudinal corrugated portions of the corrugated sheet are each arranged in a corresponding longitudinal groove (319) formed by the inner wall (312) of the housing.

8. The transmission assembly according to any one of claims 1 to 7, wherein: The housing is closed via a closing mechanism (117, 217, 317).

9. The transmission assembly according to any one of claims 1 to 8, wherein: The housing is sealed.

10. The transmission assembly according to claim 8 or claim 9, wherein: The closing mechanism is a plug mounted on the rotor shaft or the transmission shaft by press-fitting, threaded connection, or adhesive bonding on the rotor shaft or the transmission shaft.

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