Device for transmitting torque between a torque generator and a torque adapter, in particular for a motor vehicle
Patent Information
- Application Number
- EP2024722282
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-04-26
- Filing Date
- 2024-04-26
- Publication Date
- 2026-03-04
AI Technical Summary
Existing torque transmission systems between electric motors and gearboxes in motor vehicles are prone to jamming and axial shocks due to coaxiality defects and out-of-roundness, which can damage neighboring components.
A torque transmission device featuring a coupling part with teeth that allows movable connection between the torque generator and torque adapter shafts, enabling compensation for axial movements and misalignments, and includes lubrication channels and seals to reduce friction and prevent damage.
The device effectively transmits torque while minimizing the risk of jamming and axial shocks, ensuring reliable operation and reducing wear on adjacent components by allowing for degrees of freedom in the shafts' alignment and providing efficient lubrication.
Smart Images
Figure EP2024061681_31102024_PF_FP_ABST
Abstract
Description
[0001] DESCRIPTION
[0002] TITLE: Device for transmitting torque between a torque generator and a torque adapter, in particular for a motor vehicle
[0003] The invention relates to a device for transmitting torque between a torque generator and a torque adapter, in particular for a motor vehicle.
[0004] In this field, as illustrated in Figure 1, it is known to carry out a torque transmission between an electric motor 1 and a gearbox 2 by axially inserting a shaft 3, coming from the gearbox 2, into a bore 5 formed in a shaft 7, coming from the motor 1. However, this connection, made at a zone marked 8, presents risks of jamming of the shafts 3, 7, in particular due to coaxiality defects and out-of-roundness. In addition, it allows axial shocks to occur between the two shafts 3, 7. Such shocks are likely to damage neighboring parts.
[0005] The invention aims to at least partially overcome the above drawbacks and to this end proposes a device for transmitting torque between a torque generator and a torque adapter, the device comprising a shaft of said torque generator, a shaft of said torque adapter and a coupling part, said shaft of the torque generator having a first recess, said shaft of the torque adapter having a second recess, said coupling part being housed in said first and second recesses so as to transmit a torque between said shafts of the torque generator and the torque adapter, said coupling part being configured to engage with said first and / or said second shaft by teeth mutually allowing a movable connection between said coupling part, on the one hand, and the first and / or said second shaft, on the other hand.
[0006] Thanks to said teeth, the coupling part provides a drive of the torque adapter shaft by the torque generator shaft with degrees of freedom allowing compensation of axial movements or misalignments of the shafts, this in a reduced environment due to the positioning of the coupling part inside the shafts.
[0007] According to various additional characteristics of the invention, which may be taken together or separately and which form as many embodiments of the invention:
[0008] - said mobile link is a double annular linear link,
[0009] - a portion, called the end portion, of said torque adapter shaft is housed in the first recess,
[0010] - a portion of said second recess extends axially along said end portion of said torque adapter shaft,
[0011] - first of said teeth are located on said shaft of the torque generator and a first drive zone of said coupling part,
[0012] - said first drive zone extends axially between a free axial end of said torque adapter shaft and a bottom of said first recess,
[0013] - second of said teeth are located on said shaft of the torque adapter and a second drive zone of said coupling part,
[0014] - said first drive zone has a diameter greater than a diameter of said second drive zone,
[0015] - said teeth comprise a plurality of teeth angularly distributed over at least part of a circumference of said coupling part, said first recess and / or said second recess,
[0016] - at least some of said teeth have curved surfaces so as to create said mobile connection,
[0017] - said curved surfaces are present on two opposite sides of the teeth,
[0018] - said curved surfaces extend, on the one hand, between two opposite axial edges and, on the other hand, between a base active edge and a free active edge, each of said active edges connecting said axial edges,
[0019] - said curved surfaces have a first curved profile connecting said axial edges, - said curved surfaces have a second curved profile connecting said active edges,
[0020] - said curved surfaces have a vertex resulting from said first and second profiles,
[0021] - said vertex is located substantially in a center of said curved surfaces,
[0022] - said coupling part, in particular said first zone, has a free face, opposite a side connected to said second zone,
[0023] - said free face of the first zone is curved,
[0024] - said device has a first channel for the passage of a lubricating liquid arranged between, on the one hand, the coupling part and, on the other hand, a lateral surface of said first recess and / or a lateral surface of said second recess,
[0025] - said first passage channel comprises a first longitudinal portion formed in the first drive zone between two of said teeth having an angular spacing greater than an angular spacing provided between the other of said teeth of said first drive zone,
[0026] - said first passage channel comprises a second longitudinal portion formed in the second drive zone between two of said teeth having an angular spacing greater than an angular spacing provided between the other of said teeth of said second drive zone,
[0027] - the first portion of the first channel is angularly offset relative to the second portion of said first channel,
[0028] - said device has an annular groove, located axially between the first drive zone and the second drive zone, said annular groove connecting said first and second portions of said first channel,
[0029] - said coupling part has a second channel for the passage of the lubricating liquid,
[0030] - said second channel extends linearly along a longitudinal axis of said coupling part, - said first channel is connected to the second channel by a bore formed in said coupling part so that the lubricating liquid passing through the first channel undergoes a suction effect by the lubricating liquid passing through the second channel,
[0031] - said device comprises at least one stop making it possible to limit axial movement of said coupling part in the first recess and / or the second recess,
[0032] - a first of said stops is located at a first axial end of said second drive zone,
[0033] - a second of said stops is located at a second axial end of said second drive zone, opposite the first end,
[0034] - said device comprises a seal between said end portion of the torque adapter shaft and the shaft of said torque generator,
[0035] - said seal is formed from an elastomer seal,
[0036] - said seal has a straight section provided with several lobes,
[0037] - an axial end of the teeth of the toothing of the first drive zone is configured as a point to guide the coupling part in the first recess when mounting the coupling part in the shaft of the torque generator,
[0038] - said coupling part comprises a toothed crown intended to guide the coupling part in the second recess when mounting the coupling part in the shaft of the torque adapter.
[0039] The invention also relates to an assembly of a torque generator, in particular an electric machine, a torque adapter, in particular a gearbox, and a coupling part of the torque transmission device described above. Said electric machine comprises, for example, a stator and / or an axial flux rotor.
[0040] The invention also relates to a vehicle, in particular a motor vehicle, comprising an assembly as described above. The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly during the detailed explanatory description which follows, of at least one embodiment of the invention given by way of purely illustrative and non-limiting example, with reference to the appended schematic drawings among which:
[0041] [Fig 1], already commented on, illustrates schematically, according to an axial section plane, an electric machine linked to a gearbox according to the state of the art;
[0042] [Fig 2] schematically illustrates an example, along an axial section plane, of an example of a transmission device according to the invention;
[0043] [Fig 3] schematically illustrates, in perspective, a coupling part of the device of figure 2;
[0044] [Fig 4] schematically illustrates a tooth of a toothing of the part of figure 3, detailing:
[0045] - in figure 4a, a first curvature of a surface of said tooth, illustrated in perspective,
[0046] - in figure 4b a profile of said first curvature,
[0047] - in figure 4c, a second curvature of a surface of said tooth, illustrated in perspective,
[0048] - in figure 4d, a profile of said second curvature;
[0049] [Fig 5] illustrates schematically, from the side and in exploded form, the coupling part of figure 3 with a shaft of the transmission device according to the invention, the shaft being illustrated partially and according to an axial section plane;
[0050] [Fig 6] schematically illustrates, in perspective, a cross-section of a joint used in the device of Figure 2;
[0051] [Fig 7] schematically illustrates, along an axial section plane, another example of a transmission device according to the invention.
[0052] As illustrated in Figure 2, the invention relates to a device for transmitting torque between a torque generator 10, in particular an electric machine, and a torque adapter 12, in particular a gearbox. It will find its applications in particular in motor vehicles.
[0053] Said device comprises a shaft 14 of said torque generator 10, a shaft 16 of said torque adapter 12 and a coupling part 18. They are aligned along a longitudinal axis X-X' around which they are rotated according to the illustrated arrow R. In Figure 2, the generator and the torque adapter 10, 12 are only partially illustrated. Apart from their shaft 14, 16, these are for example the electric machine and the gearbox illustrated in Figure 1.
[0054] Said shaft 14 of the torque generator 10 is here configured to be driven by a rotor of said electrical machine. Said machine further comprises, in particular, a stator 20 and a bearing device 22, located between said stator 20 and said shaft 14 of the torque generator 10. Said shaft 16 of the torque adapter 12 is configured to be driven by a primary shaft of the gearbox. Said gearbox further comprises, in particular, a casing 24 a bearing device 26, located between said casing 24 and said shaft 16 of the torque adapter 12.
[0055] Said shaft 14 of the torque generator 10 has a first recess 28. It can be noted that the shaft 14 of the torque generator 10 is only slightly modified compared to that of the state of the art, which will make it possible to avoid a complete development of a new part.
[0056] According to the invention, the shaft 16 of the torque adapter 12 is also hollow. Said shaft 16 of the torque adapter 12 thus has a second recess 30 and said coupling piece 18 is housed in said first and second recesses 28, 30 so as to transmit a torque between said shafts 14, 16 of the torque generator 10 and the torque adapter 12. The rotation of the shaft 14 of the torque generator 10 is thus transmitted to the shaft 16 of the torque adapter 12 via the coupling piece 18. Said first and second recesses 28, 30 are preferably formed by a substantially cylindrical bore.
[0057] A portion 16', called the end portion, of said shaft 16 of the torque adapter 12 is advantageously housed in the first recess 28, over a portion of its length. Inside said shaft 16 of the torque adapter 12, a portion of said second recess 30 extends axially along said end portion 16' to open onto said first recess 28. Said first recess 28 is located at a portion 14d, called the distal portion, of said shaft 14 of the torque generator 10, axially extending a portion 14p, called the proximal portion, intended to be connected to the rotor of said electrical machine. Here, said shaft 14 of the torque generator 10 is hollow over its entire length. In said distal portion 14d, it has a diameter greater than that of said proximal portion 14b, internally and / or externally.
[0058] Furthermore, according to the invention, said coupling part 18 is configured to engage with said first and / or said second shaft by teeth mutually allowing a movable connection between said coupling part 18, on the one hand, and the first and / or said second shaft, on the other hand.
[0059] In the illustrated embodiment, such teeth 32a, 34a are better visible in figure 3 with regard to the teeth of the cutting part 18. They are visible in figure 2 for the teeth 32b, 34b of the shafts 14, 16 of said torque generator 10 and of said torque adapter 12.
[0060] Thus, thanks to said teeth, the coupling part 18 provides a drive of the shaft 16 of the torque adapter 12 by the shaft 16 of the torque generator 10 with degrees of freedom making it possible to compensate for axial movements or misalignments of the shafts, this in an environment reduced by the positioning of the coupling part 18 inside the shafts 14, 16.
[0061] Said movable connection is, for example, a double annular linear connection, namely a first annular linear connection between said connecting piece 18 and the shaft 14 of the torque generator 10 and a second annular linear connection between said connecting piece 18 and the shaft 16 of the torque adapter 12. Said annular linear connections thus provide axial and radial degrees of freedom between said connecting piece 18 and each of the shafts 14, 16 of the torque generator 10 and the torque adapter 12.
[0062] In the illustrated embodiment, as already stated, first of said teeth are located on said shaft 14 of the torque generator 10 and on said coupling part 18. These are the illustrated teeth 32a, 34a. The teeth 32a of the coupling part 18 are located at a first drive zone 18a of said coupling part 18. Said first drive zone 18a extends axially between a free axial end 36 of said shaft 16 of the torque adapter 12 and a bottom 38 of said first recess 28. Second of said teeth are located on said shaft 16 of the torque adapter 12 and said coupling part 18. These are the teeth 32b, 34b. The teeth 32b of the coupling part 18b are located at the level of a second drive zone 18b of said coupling part, namely that extending inside said second housing 30.Said coupling part 18 preferably has a cross section of circular configuration forming a base from which the teeth 32a, 32b extend radially, outwards. The same applies to said first and second recesses 28, 30 in which said teeth 34a, 34b extend radially, inwards (as is better seen in FIG. 5 for the second recess 30).
[0063] Said first zone 18a has a diameter greater than a diameter of said second zone 18b. Such a configuration is here associated with the insertion of the shaft 16 of said torque adapter into the shaft 14 of said torque generator 10, already mentioned above. As a variant, not illustrated, it may have a relatively constant cross section, in particular in cases where the shaft 16 of said torque adapter and the shaft 14 of said torque generator 10 have the same internal diameter and are in the axial extension of one another instead of one being inserted into the other.
[0064] Said first zone 18a has a free face 19, opposite a side 20 in connection with said second zone 18b. Said free face 19 of the first zone 18a is curved. An advantage of such a configuration will be mentioned later.
[0065] It can be seen that said coupling part 18 has the shape of a champagne cork and / or a mushroom.
[0066] Said teeth 32a, 32b, 34a, 34b comprise a plurality of teeth 40 angularly distributed over at least part of a circumference of said coupling part 18, of said first recess 28 and / or of said second recess 30.
[0067] As illustrated in Figures 4a and 4c, at least some of said teeth 40, preferably all of said teeth, have curved surfaces 42 so as to produce said movable connection. Said curved surfaces 42 of the teeth 40 of the coupling part 18 and said curved surfaces 42 of the teeth 40 of said first recess 28 and / or said second recess 30 are located opposite each other and said teeth 40 of the teeth 32a, 32b, 34a, 34b of the coupling part 18 and said first recess 28 and / or said second recess 30 respectively engage each other via said curved surfaces.
[0068] Said teeth 40 have a substantially trapezoidal shape. They are provided with a plane of symmetry passing through the longitudinal axis X-X'. Said curved surfaces 42 are here present at two large opposite sides of the teeth 40. They extend, on the one hand, between two opposite axial edges 48, 50 and, on the other hand, between a base active edge 52 and a free active edge 54, each of said active edges 52, 54 connecting said axial edges 48, 50.
[0069] As is more clearly seen in Figures 4a and 4b, said curved surfaces 42 have a first curved profile 56 connecting said axial edges 48, 50. A vertex 58 of said first profile 56 is located here in the middle of said first profile. Such a first profile 58 is encountered on said curved surfaces 42 of said active base edge 52 to said free active edge 54. Its height, namely a distance between its chord 60 and its vertex 58, is possibly variable between the active base edge 52 and said free active edge 54. It is exaggerated in figure 4b and it is preferably much less than a length of said chords 60. Said first profile 56 favors a degree of axial freedom between said teeth 32a, 32b, 34a, 34b of the coupling part 18 and said first recess 28 and / or said second recess 30.
[0070] As is more clearly seen in Figures 4c and 4d, said curved surfaces 42 have a second curved profile 62 connecting the base active edge 52 and said free active edge 54. A vertex 64 of said second profile 62 is located here in the middle of said second profile. Such a second profile 62 is found on said curved surfaces 42 between said axial edges 48, 50. Its height, namely a distance between its chord 66 and its apex 64, is possibly variable between said axial edges 48, 50. It is exaggerated in FIG. 4d and it is preferably much less than a length of said chords 66. Said second profile 62 promotes a radial degree of freedom between said teeth 32a, 32b, 34a, 34b of the coupling part 18 and said first recess 28 and / or said second recess 30.
[0071] Although they are illustrated separately in said figures 4a and 4c in order to make them more visible, said first and second profiles 56, 62 are present in combination on said curved surfaces 42. It is understood that said curved surfaces 42 thus have a vertex resulting from said first and second profiles 56, 62. The vertex of said curved surfaces 42 is advantageously located substantially in a center of said curved surfaces 42.
[0072] Referring again to Figure 3, it can be seen that said device has a first channel 68 for the passage of a lubricating liquid. Said first channel 68 is arranged between, on the one hand, the coupling part 18 and, on the other hand, a lateral surface of said first recess 28 and / or a lateral surface of said second recess 30. Said first channel 68 allows lubrication of said teeth 32a, 32b, 34a, 34b, in particular using the lubricating liquid circulating inside said shafts 14, 16.
[0073] Said first passage channel 68 comprises a first longitudinal portion 68a, formed in the first drive zone 18a between two of said teeth 40 having an angular spacing greater than an angular spacing provided between the others of said teeth 40 of said first drive zone 18a.
[0074] Said first passage channel 68 comprises a second longitudinal portion 68b formed in the second drive zone 18b between two of said teeth 40 having an angular spacing greater than an angular spacing provided between the others of said teeth 40 of said second drive zone 18b.
[0075] In other words, said first and second portions 68a, 68b of the channel 68 correspond to the absence or the elimination of one or more of said teeth 60 relative to a configuration with a regular angular distribution of said teeth 60 over the entire circumference of the first and second drive zones 18a, 18b.
[0076] The first portion 68a of the channel 68 is here angularly offset relative to the second portion 68b of said channel 68, for example by 90°.
[0077] If we refer again to Figure 2, we see that said device also has an annular groove 70, located axially between the first drive zone 18a and the second drive zone 18b, outside said coupling part 18. Said groove 70 and said angular offset of the different portions 68a, 68b of the channel 68, taken together or separately, promote good distribution of the lubricating liquid at the level of all the teeth 32a, 32b, 34a, 34b.
[0078] Said coupling part 18 advantageously has a second channel 72 for the passage of the lubricating liquid. Said second channel 72 extends linearly along the longitudinal axis X-X' of the coupling part 18. It serves as a lubricant supply between the torque generator 10 and the torque adapter 12.
[0079] Said first channel 68, in particular said second portion 68b of said first channel 68, is connected to the second channel 72 by a bore 74 formed in said coupling part 18 so that the lubricating liquid passing through the first channel 68 undergoes a suction effect by the lubricating liquid passing through the second channel 72, in particular by a Venturi effect. A compromise is made between passage sections of the first channel 68 and of the second channel 72 to minimize pressure losses on the lubricating liquid while having sufficient flow in each of said first and second channels 68, 72. The domed nature of the free surface 19 also contributes to good distribution of the lubricating liquid.
[0080] As illustrated in Figure 5, said device advantageously comprises at least one stop, here two stops 76, 78, making it possible to limit an axial movement of said coupling part 68 in the first recess 20 and / or the second recess 30.
[0081] The said stop(s) 76, 78 comprise, for example, at least one circular groove 80 and a shoulder 82 arranged opposite. They further comprise a ring, not illustrated, housed in the said groove 80, preferably with axial play and / or radial play, and intended to come into contact with the said shoulder 82.
[0082] One of said grooves 80 or shoulders 82 is located on said coupling part 18, and the other on said shaft(s) 14, 16 of the torque generator 10 and / or of the torque adapter 12. Here, said grooves 80 are located on said coupling part 18 and the shoulders 82 on said shaft 16 of the torque adapter 12.
[0083] More precisely, a first of said stops 78 is located at a first axial end 84, free, of said second drive zone 18b. A second 76 of said stops is located at a second axial end of said second drive zone 18b, opposite the first axial end 84 and in correspondence with said side 20 of said first zone 18a in connection with said second zone 18b. Even more precisely, said stops 76, 78 are located on either side of said teeth 34a, 34b of said second drive zone 18b and of said second internal housing 30. Said shoulders 82 are possibly formed from an axial end of the teeth 34b of said second internal housing 30.
[0084] In the illustrated embodiment, an axial end of the teeth 40 of the toothing 32a of the first drive zone 18a is configured as a point to guide the coupling part 18 in the first recess 28 when the coupling part 18 is mounted in the shaft 14 of the torque generator. Said coupling part 18 further comprises a toothed crown 89 intended to guide the coupling part 18 in the second recess 30 when the coupling part 18 is mounted in the shaft 16 of the torque adapter 12.
[0085] Referring again to Figure 2, it can be seen that said device further comprises here a seal 90 between said end portion 16' of the shaft 16 of the torque adapter 12 and an end portion of the shaft 14 of said torque generator 10. It is located, in particular, between an external surface of said shaft 16 of the torque adapter 12 and an internal surface of said shaft 14 of the torque generator 10, for example in a groove, here formed in said shaft 16 of the torque adapter 12.
[0086] As illustrated in Figure 6, said seal 90 preferably has a straight section provided with several lobes 92. It is, for example, quadrilobe. Said seal 90 is formed, for example, from an elastomer seal.
[0087] The invention also relates to an assembly of a torque generator 10, a torque adapter 12 and a coupling part 18 of the torque transmission device as described above. As already indicated, apart from their shaft 14, 16, these are, for example, the electric machine and the gearbox illustrated in FIG. 1.
[0088] As illustrated in Figure 7, alternatively, the electrical machine 10 comprises a stator and / or a rotor 100 with axial flux.
[0089] The performance of an axial flux electric machine is particularly linked to the axial position of the rotor 100 equidistant from two stators of the machine. The device according to the invention makes it possible to reduce the forces transmitted by the gearbox and limits their influence on the axial position of the rotor 100. It thus contributes to good efficiency of the assembly.
Claims
CLAIMS 1 . A device for transmitting torque between a torque generator (10) and a torque adapter (12), the device comprising a shaft (14) of said torque generator (10), a shaft (16) of said torque adapter (12) and a coupling piece (18), said shaft (10) of the torque generator (12) having a first recess (28), said shaft (16) of the torque adapter (12) having a second recess (30), said coupling piece (18) being housed in said first and second recesses (28, 30) so as to transmit a torque between said shafts (14, 16) of the torque generator (10) and of the torque adapter (12), said coupling piece (18) being configured to engage with said first and / or said second shaft by teeth (32a, 34a, 32b, 34b) mutually allowing a movable connection between said coupling piece (18), on the one hand, and the first and / or said second shaft, on the other hand.
2. Device according to claim 1 wherein said movable link is a double annular linear link.
3. Device according to any one of the preceding claims in which a portion (16'), called the end portion, of said shaft (16) of the torque adapter (12) is housed in the first recess (28), a part of said second recess (30) extending axially along said end portion (16').
4. Device according to any one of the preceding claims in which first (32a, 32b) of said teeth are located on said shaft (14) of the torque generator (10) and a first drive zone (18a) of said coupling part (18) and / or second (34a, 34b) of said teeth are located on said shaft (16) of the torque adapter (12) and a second drive zone (18b) of said coupling part (18).
5. Device according to any one of the preceding claims in which said teeth (32a, 34a, 32b, 34b) comprise a plurality of teeth (40) angularly distributed over at least part of a circumference of said part. coupling (18), said first recess (28) and / or said second recess (30), at least some of said teeth (40) having curved surfaces (42) so as to produce said movable connection.
6. Device according to the preceding claim in which said curved surfaces (42) extend, on the one hand, between two opposite axial edges (48, 50) and, on the other hand, between a base active edge (52) and a free active edge (54), each of said active edges (52, 54) connecting said axial edges (48, 50), said curved surfaces (42) having a first curved profile (56) connecting said axial edges (48, 50) and / or a second curved profile (62) connecting said active edges (52, 54).
7. Device according to any one of the preceding claims in which said coupling part (18) has a curved free face (19).
8. Device according to any one of the preceding claims having a first channel (68) for the passage of a lubricating liquid formed between, on the one hand, the coupling part (18) and, on the other hand, a lateral surface of said first recess (28) and / or a lateral surface of said second recess (30).
9. Device according to the preceding claim in which said coupling part (18) has a second channel (72) for the passage of the lubricating liquid, said second channel (72) extending linearly along a longitudinal axis of said coupling part (18).
10. Device according to the preceding claim in which said first channel (68) is connected to the second channel (72) by a bore (74) formed in said coupling part (18) so that the lubricating liquid passing through the first channel (68) undergoes a suction effect by the lubricating liquid passing through the second channel (72).
11. Device according to any one of the preceding claims comprising at least one stop (76, 78) making it possible to limit axial movement. of said coupling part (18) in the first recess (28) and / or the second recess (30).
12. Device according to any one of the preceding claims comprising a seal (90) between the shaft (16) the torque adapter (12) and the shaft (14) of said torque generator (10), said seal (90) has a straight section provided with several lobes (92).
13. Assembly of a torque generator (10), a torque adapter (12) and a coupling part (18) of the torque transmission device according to any one of the preceding claims.
14. Assembly according to the preceding claim in which the torque generator (10) comprises an electric machine, said electric machine comprising a stator and / or a rotor (100) with axial flux.
15. Vehicle comprising an assembly according to any one of claims 13 or 14.