Transmission module for hybrid drive vehicle

Abstract

A transmission module for a hybrid drive assembly of a vehicle, the hybrid drive assembly comprising an internal combustion engine provided with a drive shaft, at least one electric machine (2) and a transmission of the vehicle, the transmission module being configured to be interposed between the internal combustion engine and the transmission, and the transmission module comprising: a support structure (11), the support structure (11) is configured to be fixed to the internal combustion engine and to define a housing (23); a transmission assembly (12) housed in a housing (23) defined by the support structure (11) and comprising a first element (41) having an axis (A) coincident with the axis of the drive shaft in use and configured to be operatively connected to the internal combustion engine and the electric machine (2), and a second element (42) configured to be connected to a transmission of the vehicle, where the first element (41) has an axis (A) coincident with the axis of the drive shaft in use and is configured to be operatively connected to the internal combustion engine and to the electric machine (2), and where the second element (42) has an axis (A) coincident with the axis of the drive shaft in use. The first element (41) and the second element (42) are different components rigidly coupled to each other.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims the priority of Italian patent application No. 102022000016713 filed on August 4, 2022, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The present invention relates to a transmission module for a hybrid vehicle, and in particular to a transmission module configured to be inserted between an internal combustion engine and a transmission device of the hybrid vehicle. Background Art

[0004] As is known, hybrid vehicles include an internal combustion engine and at least one electric machine, which may function as a generator or a motor to supply drive torque in conjunction with (or in place of) the internal combustion engine, depending on the operating conditions of the vehicle.

[0005] Configurations in which an electric machine connected between the internal combustion engine and the transmission of a vehicle is used are conventionally referred to as "P2" or "P1", respectively, based on the presence or absence of certain elements described below.

[0006] In particular, a transmission module configured to be interposed between an internal combustion engine and a transmission of a vehicle is generally referred to as:

[0007] - a "P2 module", if it comprises, in addition to the electric machine, a clutch which selectively connects the internal combustion engine and the electric machine to one another;

[0008] - "P1 module", if it comprises an electric machine but no such clutch.

[0009] Therefore, the P1 module can be considered a special case of the P2 module, since the internal combustion engine and the electric machine are permanently connected to each other.

[0010] A problem associated with known P1 modules is the manufacture of their components, which have complex geometries and expensive production processes. In particular, the installation of the P1 modules is particularly complex, thus extending the manufacturing time and increasing the relative costs.

[0011] The object of the present invention is to provide a transmission module of the P1 type which allows overcoming the above-mentioned problems. Summary of the invention

[0012] The above objects are achieved by a module according to the attached claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] For a better understanding of the present invention, preferred embodiments are described hereinafter by way of non-limiting examples with reference to the accompanying drawings, in which:

[0014] Figure 1 is an exploded view of a hybrid power unit including a transmission module according to a first embodiment of the present invention;

[0015] Figure 2 yes Figure 1 Axial cross-sectional view of a unit cell;

[0016] Figure 3 yes Figure 2 A magnified view of the details;

[0017] Figure 4 is an exploded view of a hybrid power unit including a transmission module according to a second embodiment of the present invention;

[0018] Figure 5 yes Figure 4 Axial cross-sectional view of a unit cell;

[0019] Figure 6 yes Figure 5 A magnified view of the details. DETAILED DESCRIPTION

[0020] refer to Figure 1 , denoted by 1 is a transmission module according to the present invention.

[0021] The module 1 is configured to be connected between an internal combustion engine and a transmission of a hybrid drive vehicle, thereby forming together a hybrid drive assembly which also includes an electric machine 2 .

[0022] The module 1 is part of a hybrid power unit 3 which comprises, in addition to the module itself, an electric machine 2. Conveniently, the electric machine 2 is of reversible type, ie it can be operated as a motor to supply torque to a transmission, or as a generator to generate electricity.

[0023] The module 1 comprises a support structure 11 configured to be fixed to an internal combustion engine and a transmission assembly 12 housed in the support structure 11 and configured to operatively connect a drive shaft of the internal combustion engine, the electric machine 2 and the transmission to one another.

[0024] The support structure 11 comprises a fastening element 21 and a closing element 22 which is rigidly coupled to the fastening element 21 and defines together with it a housing 23 for further components of the hybrid unit 3 , which is described in detail below.

[0025] In particular, the fastening element 21 comprises a substantially cylindrical wall 24 extending along an axis A coinciding with the axis of the drive shaft in use. The wall 24 is provided at its axial end with a peripheral flange 25 extending in radial direction from opposite sides of the housing 23 and preferably orthogonal thereto and having a plurality of holes 26 for fixing to the internal combustion engine.

[0026] From the opposite side of the housing 23 , the wall 24 defines a plurality of projections 27 extending radially from the wall 24 and axially along the entire extent of the wall 24 relative to the axis A. In the projections 27 there are holes for coupling the fastening element 21 to the closing element 22 .

[0027] The closing element 22 comprises a substantially annular plate 31 of axis A provided with a plurality of radial projections 32 extending along its outer edge defining respective through holes for respective protrusions 27 of the wall 24. A tubular appendix 33 extends axially from the inner edge of the plate 31 towards the flange 25.

[0028] Conveniently, the closing element 22 carries a sleeve 34 with axis A, which extends axially towards the flange 25 and is in contact externally with the wall 24 of the fastening element 21 , ie from the opposite side of the housing 23 .

[0029] The closing element 22 and the sleeve 34 define between them a channel in which a coolant configured to cool the motor 2 can flow. In particular, the motor 2 comprises a stator 35 having an axis A, the stator 35 being in contact with the sleeve 34 on the outside, and a rotor 36 coaxial with the stator 35 and radially inside relative to the stator 35.

[0030] The transmission assembly 12 , which is conveniently housed in the housing 23 , includes a first element 41 configured to be operatively connected to the internal combustion engine and the electric machine 2 , and a second element 42 configured to be connected to a transmission of the vehicle.

[0031] Conveniently, the first element 41 and the second element 42 are distinct components rigidly coupled to each other, as described in detail below.

[0032] The first element 41 , which is conveniently axisymmetric relative to the axis A, comprises a support portion 51 configured to support the rotor 36 of the electric machine 2 and a connection portion 52 configured to be driven by the internal combustion engine.

[0033] In particular, the support portion 51 of the first element 41 has a substantially annular shape around the axis A and preferably has an L-shaped cross section. In particular, the support portion 51 comprises a cylindrical wall 53 with the axis A, defining a radial support for the rotor 36, and a radial wall 54 with the axis A, defining an axial stop for the rotor 36 and extending from the axial end of the cylindrical wall 53 facing the internal combustion engine in use. Conveniently, the support portion 51 is configured to rotate with the rotor 36 around the axis A.

[0034] The connecting portion 52 of the first element 41 has a substantially annular shape and comprises a substantially cylindrical body 55 and a radial appendage 56 extending towards the axis A from the axial end of the body 55 facing the closing element 22 .

[0035] Conveniently, the support portion 51 and the connection portion 52 are connected by a joining portion 61. In particular, the joining portion 61 comprises an outer radial wall 62 extending from the cylindrical wall 53 of the support portion 51, an inner radial wall 63 extending from the body 55 of the connection portion 52, and an intermediate wall 64 extending substantially axially and joining the outer radial wall 62 and the inner radial wall 63.

[0036] Conveniently, the supporting portion 51 , the connecting portion 52 and the joining portion 61 are made in one piece.

[0037] The second element 42 of the transmission assembly 12 comprises a fastening portion 71 rigidly coupled to the first element 41 and a hub portion 72 coaxial with the first element 41 .

[0038] In particular, the fastening portion 71 of the second element 42 comprises an annular plate 73 extending orthogonally with respect to the axis A and a tubular appendix 74 having the axis A and extending from the inner edge of the annular plate 73 and facing the internal combustion engine in use. Conveniently, the annular plate 73 and the tubular appendix 74 are respectively in axial contact and radial contact with the support portion 51 of the first element 41 .

[0039] The hub portion 72 comprises a hub 75 having an axis A, extending in opposite directions relative to the tubular attachment 74 and configured to be connected to a transmission of a vehicle, and an annular joint 76 between the annular plate 73 and the hub 75. Conveniently, the hub 75 has a groove 77 on the inside configured to allow coupling between the hub 75 and the transmission of the vehicle.

[0040] Conveniently, the fastening portion 71 and the hub portion are made in one piece.

[0041] Preferably, the module 1 further comprises a rolling support device 81 interposed between the support structure 11 and the transmission assembly 12 .

[0042] In particular, the rolling support means 81 are bearings, preferably ball bearings, which are radially interposed between the sleeve 34 of the support structure 11 and the hub portion 72 of the transmission assembly 12 .

[0043] Conveniently, the module 1 further comprises a position sensor 82 , of a known type and therefore not described in detail hereinafter, configured to measure the relative rotation of the transmission assembly 12 , and thereby the rotor 36 , relative to the support structure 11 .

[0044] Conveniently, the transmission assembly 12 comprises fastening means 91 configured to rigidly couple the first element 41 and the second element 42 to each other.

[0045] To this end, the first element 41 has a plurality of axial first holes 101 distributed around the axis A, and the second element 42 has a plurality of axial second holes 102. Each hole is defined by an axis parallel to the axis A, and the second holes 102 are coaxial with the respective first holes 101. The first holes 101 and the second holes 102 are configured to accommodate the fastening means 91.

[0046] Preferably, the first hole 101 is arranged on the connecting portion 52 of the first element 41 , and the second hole 102 is arranged on the fastening portion 71 of the second element 42 .

[0047] Conveniently, the first hole 101 and the second hole 102 are arranged circumferentially around the axis A. In other words, the axis of the first hole 101 and thus the axis of the second hole 102 are equidistant from the axis A.

[0048] In particular, the first holes 101 and the second holes 102 may be equiangularly spaced relative to the axis A. In other words, if the number of first holes 101 (and therefore the number of second holes 102) is n, n dihedral angles (i.e. n portions of the space between the two half-planes) may be defined, such that each dihedral angle has an origin on the axis A (the two half-planes passing through the respective axis of the first hole 101 (and therefore the respective axis of the second hole 102)) and contains no other axis of the first hole 101 in its interior. All dihedral angles so defined have the same measure.

[0049] Conveniently, the first hole 101 and the second hole 102 are through holes.

[0050] According to the first embodiment of the present invention ( Figure 1-Figure 3 ), the fastening means 91 comprises a first threaded element 111. Preferably, the first threaded element 111 is a screw extending parallel to the axis A and having a corresponding head 112 facing the closing element 22.

[0051] In particular, Figure 1Eight thread elements 111 are shown, which are arranged along the circumference and are angularly separated from each other by 45°.

[0052] Conveniently ( Figure 2 and Figure 3 ), the first hole 101 is arranged on the main body 55 of the connecting part 52 of the first element 41, and the second hole 102 is arranged on the annular plate 73 of the fastening part 71 of the second element 42.

[0053] In particular ( Figure 2 ), the first hole 101 is configured to receive a second threaded element 121, the second threaded element 121 is configured to connect the first element 41 to a torque transmission element 122, the torque transmission element 122 is operatively interposed between the internal combustion engine and the first element 41 and is provided with a plurality of axial holes 123 coaxial with the first hole 101. Conveniently, the torque transmission element 122 is a flexible disk or a flexible plate.

[0054] Conveniently, the first hole 101 and the second hole 102 have the same diameter. In other words, each pair of the first hole 101 and the corresponding second hole 102 defines a single threaded cylindrical through seat 124, which is configured to accommodate the corresponding first threaded element 111 and the corresponding second threaded element 121. Preferably, the first hole 101 and the second hole 102 have the same thread, that is, the cylindrical through seat 124 has a uniform thread. Therefore, the first threaded element 111 and the second threaded element 121 also have the same thread. Optionally, the first threaded element 111 has the same structure as the second threaded element 121, that is, they can be used independently of each other.

[0055] According to the second embodiment of the present invention ( Figures 4 to 6 ), the fastening device 91 includes a rivet 131 extending parallel to the axis A.

[0056] In particular, Figure 4 Six rivets 131 are shown, arranged along the circumference and angularly separated from each other by 22.5°.

[0057] Conveniently ( Figure 5 and Figure 6 ), the first hole 101 is arranged on the radial appendage 56 of the connecting part 52 of the first element 41, and the second hole 102 is arranged on the annular plate 73 of the fastening part 71 of the second element 42.

[0058] Conveniently ( Figure 5 and Figure 6), the first element 41 has a plurality of axial third holes 141, the plurality of axial third holes 141 are configured to accommodate the second threaded element 121, the second threaded element 121 is configured to connect the first element 41 to a torque transfer element (not shown), the torque transfer element is operatively inserted between the internal combustion engine and the first element 41 and is provided with a plurality of axial holes coaxial with the third holes 141.

[0059] In particular ( Figure 5 ), the first hole 101 and the third hole 141 are arranged along a circumference centered on the axis A. In other words, the axis of the first hole 101 is equidistant from the axis A, and the axis of the third hole 141 is equidistant from the axis A. Conveniently, the distance between the axis A and the first hole 101 is smaller than the distance between the axis A and the third hole 141.

[0060] The operation of the module 1 according to the invention is as follows.

[0061] After mounting the module 1 on a vehicle, the transmission assembly 12 allows the internal combustion engine to be connected to the transmission of the vehicle. Conveniently, the torque transmission element 122 is interposed between the internal combustion engine and the first element 41 of the transmission assembly 12.

[0062] The electric machine 2 connected to the first element 41 can be used as a generator (for recharging the battery during hot traction, or for generating electricity configured to power auxiliary equipment of the vehicle (such as agricultural auxiliary equipment), or as a regenerative brake) and as an electric motor for starting the internal combustion engine or for providing additional torque during hot traction (boost).

[0063] From the above, the advantages of the module 1 according to the invention are evident.

[0064] In particular, since the first element 41 and the second element 42 are different components, they may be manufactured with different materials and / or by different production processes.

[0065] For example, the second element 42 must meet the hardness requirements of the groove 77 of the hub 75 and can therefore be conveniently manufactured by forging. However, manufacturing the first element 41 and the second element 42 as a single forged component would require complex molds and expensive production processes. On the contrary, according to the present invention, the first element 41 is different from the second element 42 and can therefore be made of another material (e.g. cast iron) and by another process (e.g. fusion). This simplification has a positive impact on the entire module 1 in terms of development and cost.

[0066] Furthermore, if the first element 41 and the second element 42 are coupled via a first threaded element 111 received in the first hole 101, the same hole 101 can also be used to connect the first element 41 to a torque transfer element 122, such as a flexible disc or a flexible plate, which is operatively interposed between the internal combustion engine and the first element 41.

[0067] Alternatively, using rivets 131 to couple the first and second elements 41 , 42 allows for a more compact coupling and less volume, which is particularly convenient when tighter volume constraints exist.

[0068] Finally, it is clear that modifications and variations may be made to module 1 without departing from the scope of protection defined by the claims.

[0069] For example, the first element 41 and the second element 42 may have structures different from those described and be rigidly coupled to each other in other suitable manners.

[0070] Furthermore, the support structure 11 and the transmission assembly 12 may have a different structure than that described, or include additional elements that are not described for the sake of brevity.

[0071] The distance between the axis A and the first hole 101 may be greater than the distance between the axis A and the third hole 141 .

Claims

1. A transmission module for a hybrid drive assembly of a vehicle, the hybrid drive assembly comprising an internal combustion engine provided with a drive shaft, at least one electric motor (2) and a transmission device of the vehicle, the transmission module being configured to be inserted between the internal combustion engine and the transmission device, and comprising: a support structure (11) configured to be fixed to the internal combustion engine and defining a housing (23); a transmission assembly (12), the transmission assembly (12) being housed in the housing (23) defined by the support structure (11) and comprising a first element (41) and a second element (42), wherein the first element (41) has an axis (A) which coincides with the axis of the drive shaft in use and is configured to be operatively connected to the internal combustion engine and the electric machine (2), wherein the second element (42) is configured to be connected to the transmission of the vehicle, The first element (41) and the second element (42) are different components rigidly connected to each other.

2. The module according to claim 1, wherein: The transmission assembly (12) comprises a fastening device (91) configured to rigidly couple the first element (41) and the second element (42) to each other.

3. The module according to claim 2, wherein: The first element (41) includes a support portion (51) configured to support a rotor (36) of the motor (2) and a connection portion (52) configured to be driven by the internal combustion engine, and the second element (42) includes a fastening portion (71) rigidly connected to the first element (41) and a hub portion (72) coaxial with the first element (41).

4. The module according to claim 3, wherein: At least one of the connecting portion (52) of the first element (41) and the fastening portion (71) of the second element (42) extends substantially orthogonally relative to the axis (A).

5. A module according to claim 3 or 4, comprising rolling support means (81) interposed between the hub portion (72) and an end portion (33) of the support structure (11) extending substantially parallel to the axis (A).

6. A module according to any one of claims 2 to 5, wherein: The first element (41) has a plurality of axial first holes (101) distributed around the axis (A), and the second element (42) has a plurality of axial second holes (102) coaxial with the first holes (101), and the first holes (101) and the second holes (102) are configured to accommodate the fastening device (91).

7. The module according to claim 6, wherein: The first hole (101) and the second hole (102) are arranged circumferentially around the axis (A).

8. The module according to claim 6 or 7, wherein: The first hole (101) and the second hole (102) are equiangularly spaced relative to the axis (A).

9. A module according to any one of claims 6 to 8, wherein: The first hole (101) and the second hole (102) are through holes.

10. A module according to any one of claims 2 to 9, wherein: The fastening device (91) comprises a first threaded element (111).

11. A module according to claim 10 when dependent on claim 6, wherein The first hole (101) is configured to accommodate a second threaded element (121), which is configured to connect the first element (41) to a torque transfer element (122), which is operatively interposed between the internal combustion engine and the first element (41) and is provided with a plurality of axial holes (123) coaxial with the first hole (101).

12. The module according to claim 11, wherein The first hole (101) and the second hole (102) have the same diameter.

13. The module according to claim 12, wherein: The first hole (101) and the second hole (102) have the same thread.

14. A module according to any one of claims 2 to 9, wherein: The fastening device (91) comprises a rivet (131).

15. The module according to claim 14, wherein: The first element (41) has a plurality of axial third holes (141), and the plurality of axial third holes (141) are configured to accommodate a second threaded element (121), and the second threaded element (121) is configured to connect the first element (41) to a torque transmission element (122), and the torque transmission element (122) is operatively inserted between the internal combustion engine and the first element (41) and is provided with a plurality of axial holes (123) coaxial with the third holes (141).

16. A module according to claim 15 when dependent on claim 7, wherein The distance between the axis (A) and the first hole (101) is smaller than the distance between the axis (A) and the third hole (141).

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