Electric drive module with labyrinth seal

Abstract

The invention relates to an electric drive module (1) for a motor vehicle, comprising a housing (2), a shaft body (5) which protrudes through an opening (3) of the housing (2) into an interior (4) of the housing (2), and a bearing (6) which supports the shaft body (5) relative to the housing (2), a labyrinth seal (8) is inserted between the housing (2) and the shaft body (6) in a manner effective between the housing (2) and the shaft body (6), the labyrinth seal (8) having an inner ring (9) and an outer ring (10) arranged radially without contact with the inner ring (9), the outer ring (10) further having a plurality of return openings (11) radially penetrating the outer ring, the return opening (11) is connected to a return channel (12) introduced into the housing (2).

Description

Technical Field

[0001] The present invention relates to an electric drive module for a motor vehicle, such as a passenger car, a truck, a bus or other commercial vehicle. Herein, the drive module is preferably configured as a so-called e-axle / electric drive axle. Summary of the Invention

[0002] The object of the present invention is to improve the efficiency of the drive module and at the same time not increase or only slightly increase the existing installation space.

[0003] According to the present invention, the above object is achieved by the subject matter of claim 1. A claim 1 is used to claim an electric drive module for a motor vehicle, which has a housing, a shaft body extending into the interior of the housing through an opening of the housing, and a bearing for supporting the shaft body relative to the housing. Wherein, on a side of the bearing facing the environment of the housing, a labyrinth seal is inserted in a manner that acts between the housing and the shaft body. Wherein, the labyrinth seal also has an inner ring and an outer ring arranged radially non-contact with respect to the inner ring. Wherein, the outer ring also has a plurality of return holes radially penetrating the outer ring, and the return holes are connected to a return channel introduced into the housing.

[0004] By constructing such a labyrinth seal, a clever compromise is achieved between sufficient sealing effect and as low as possible frictional losses caused by using the labyrinth seal. Herein, the frictional losses caused by the labyrinth seal are almost eliminated. Wherein, there is intentionally a certain amount of leakage, but this will be kept within limits by the existing labyrinth and can be conveniently deflected through the existing return holes.

[0005] Further advantageous embodiments are claimed by dependent claims and will be described in detail below.

[0006] Therefore, for a compact structural form, it is further advantageous that the return holes are axially arranged at the same height, that is, arranged in a common extension plane perpendicular to the rotation axis of the shaft body, and arranged in a uniformly distributed manner around the circumference.

[0007] In addition, it is advantageous to introduce at least fifteen, further preferably at least twenty return holes (in the outer ring). Thus, a particularly clever compromise is achieved between sufficient lubricant return and manufacturing cost.

[0008] In addition, for ease of manufacturing, it is advantageous that the inner ring is integrally formed and / or the outer ring is composed of multiple parts (that is, composed of multiple arc segments / housing segments).

[0009] If the return hole communicates with an annular groove that opens radially outwards in the outer ring, lubricant (such as lubricating oil) can be discharged in the circumferential position through the return channel, and this circumferential position is preferably arranged at the bottom side of the labyrinth seal relative to the installation position and the main gravity. This further reduces the manufacturing cost.

[0010] Furthermore, for a sufficient sealing effect, it is advantageous that the inner ring and the outer ring are provided with / mounted with a plurality of disk regions that are alternately arranged in the axial direction.

[0011] In order to achieve the highest possible sealing effect while maintaining a compact structural form, it has proven advantageous that the outer ring has at least two, preferably at least three, or only three disk regions that are axially spaced apart from each other.

[0012] Furthermore, in order to effectively install the return hole, it is advantageous that the return hole is introduced into the outer ring between a first disk region of the outer ring that is axially closest to the environment and a second disk region of the outer ring that is (axially) adjacent to the first disk region.

[0013] Furthermore, it is advantageous that the inner ring has at least two, preferably at least three, further preferably at least four, or only four disk regions that are axially spaced apart from each other. This achieves the highest possible sealing effect in cooperation with the outer ring.

[0014] Furthermore, it has proven advantageous to insert a sealing ring between the inner ring and the shaft body and / or between the outer ring and the housing. This sealing ring is preferably a sealing ring that is directly inserted in a radially compressed manner, and it is implemented as an O-ring, for example. This further improves the sealing of the interior of the housing.

[0015] If the sealing ring inserted in a manner that acts between the outer ring and the housing is positioned on the axially environment-facing side of the return hole, it will not have an adverse effect on the lubricating oil return during operation.

[0016] The drive module preferably has at least one electric drive machine in the housing. The drive module further preferably also has a transmission located downstream of the drive machine, which is preferably also placed in the housing. Description of the Drawings

[0017] The present invention will be described in detail below with reference to the drawings.

[0018] Among them:

[0019] Figure 1 A longitudinal sectional view of a drive module partially shown according to the present invention according to a preferred embodiment, wherein this drive module is shown in the region of a shaft body that extends from the housing and is supported in the housing.

[0020] Figure 2 Figure 2 Detailed view of the drive module shown in the area of the bearing supporting Zhou Ti and the labyrinth seal

[0021] Figure 3 Perspective overall view of the longitudinal section of the shaft body with bearings and labyrinth seals, and

[0022] Figure 4 Figure 3 Perspective view of the longitudinal section of the shaft body shown, with the outer ring removed from the labyrinth seal to make the built-in inner ring visible.

[0023] These diagrams are only schematic in nature and are only used to understand the present invention. The same elements are provided with the same reference numerals. Detailed Description of the Invention

[0024] Figure 1 Shows a part of the automotive electric drive module 1 according to the present invention, which is preferably implemented as a so-called e-axle. The drive module 1 has a housing 2, which is shown in part in Figure 1 . A power drive machine is arranged in the housing 2 in a conventional manner, and further preferably a transmission device coupled to the output end of the drive machine is arranged. For the sake of clarity, this transmission device is not shown further here. The shaft body 5 serving as an input shaft or an output shaft for entering / leaving the drive module 1 is shown in detail in Figures 1 to 4 . In the shown embodiment, the shaft body 5 is provided with an integral (here, helical-toothed) tooth region 18, wherein the tooth region 18 meshes with at least one other gear during operation. Thereby, the shaft body 5 is preferably a component of the transmission device and forms a transmission input shaft or a transmission output shaft.

[0025] The shaft body 5 is supported relative to the housing 2 in a torsionally flexible manner by two bearings 6 and 19 that can be seen in Figure 1 . The bearing that is further axially offset into the interior 4 of the housing 2 along the shaft body 5 is called the second bearing 19. The second bearing 19 is constructed as a rolling bearing, i.e., as a ball bearing. The bearing arranged close to the environment of the housing 2 is called the first bearing 6. The first bearing 6 is constructed as a rolling bearing, i.e., as a ball bearing. The two bearings 6, 19 are used to support the shaft body 5 relative to the housing 2 in a rotatable manner / to radially support this shaft body, and preferably also to axially support it.

[0026] The first bearing 6 is arranged in the area of the opening 3 in the housing 2. The opening 3 / is penetrated by the shaft body 5. Therefore, the first bearing 6 is radially inserted between the (circular) wall portion 20 (also called the hole wall pressure-bearing area) describing the opening 3 and the radial outer side of the shaft body 5.

[0027] It should be noted in this regard that the directional descriptions used in this example should be understood as the axial, radial, and circumferential directions with respect to the rotational axis 21 of the shaft body 5. Accordingly, the axial / axial direction refers to the direction along / parallel to the rotational axis 21, the radial / radial direction refers to the direction perpendicular to the rotational axis 21, and the circumferential direction refers to the direction along the circumferential line coaxially surrounding the rotational axis 21.

[0028] On the (first) axial side 7a of the first bearing 6 facing the environment of the housing 2, the labyrinth seal 8 according to the invention is inserted in such a way as to act between the housing 2 and the shaft body 5, which will be described in detail below. Accordingly, the second axial side 7b of the first bearing 6 facing away from the first axial side 7a of the first bearing 6 is the side facing the tooth region 18 and thus the interior 4 of the housing 2.

[0029] The labyrinth seal 8 is used to seal the interior 4 of the housing 2 with respect to the environment of the housing 2 in the radial clearance 25 between the housing 2 and the shaft body 5.

[0030] Combined Figures 2 to 4 Shows the detailed design of the labyrinth seal 8. In this regard, it should be noted first that the inner ring 9 is preferably realized as an integrally formed, i.e., material-bonded / integrally formed ring. The inner ring 9 is preferably made of plastic. The inner ring 9 is placed on the shaft body 5 as a whole, for example, press-fitted onto the shaft body.

[0031] The inner ring 9 has a sleeve-shaped basic section 22, which is at least partially placed / abutted against the shaft body 5 from the outside. A plurality of disk regions 15a, 15b, 15c, 15d project radially outward from the basic section 22, and this basic section has a constant diameter (inner diameter). In this embodiment, a total of four disk regions 15a to 15d are constructed, which are radially oriented and parallel to each other. However, it should be noted in this regard that the number of disk regions of the inner ring 9 is not set to four, and thus, in other embodiments, more or fewer than four disk regions can of course also be used.

[0032] It can also be seen that the two outermost disk regions 15a and 15d of the inner ring 9 in the axial direction have a larger diameter (outer diameter) compared to the two inner disk regions 15b and 15c of the inner ring 9 located between the two outermost disk regions 15a, 15d. The two inner disk regions 15b and 15c of the inner ring 9 in turn have the same diameter (outer diameter).

[0033] Furthermore, the outer ring 10 is composed of multiple parts (here two parts). The outer ring 10 consists of two arc segments 23a, 23b / arcuate segments / housing segments that each extend 180°, and it is substantially implemented as a common part. The arc segments 23a, 23b and the outer ring 10 are made of plastic here. During installation, the two arc segments 23a, 23b are placed radially from the outside above the inner ring 9 and are ultimately brought into contact with each other circumferentially, so that a labyrinth-like sealing channel / sealing gap is formed in the labyrinth seal 8 through the alternating layout of the disk regions 14a, 14b, 14c, 15a, 15b, 15c, 15d in the axial direction. The outer ring 10 composed of the two arc segments 23a, 23b is preferably directly inserted / pressed into the opening 3 / wall portion 20.

[0034] Corresponding retaining rings, not shown in detail for the sake of clarity, can be used to axially fix the outer ring 10 to the housing 2 and / or to axially fix the inner ring 9 to the shaft body 5.

[0035] The outer ring 10 also has a sleeve-shaped basic section 24, which is arranged radially outside the inner ring 9. The basic section 24 of the outer ring 10 is spaced a certain radial distance from the inner ring 9 and thus is spaced a certain radial distance from the respective disk regions 15a to 15d and the basic section 22 of the inner ring 9. Therefore, the outer ring 10 is arranged in a non-contact manner with respect to the inner ring 9. The basic section 24 of the outer ring 10 has a constant diameter (outer diameter).

[0036] Furthermore, it can also be seen that in this embodiment, the outer ring 10 has three disk regions 14a to 14c, which respectively extend into the gaps between two adjacent disk regions of the inner ring 9. Therefore, the disk regions 14a to 14c and 15a to 15d are arranged alternately with each other in the axial direction. This results in a labyrinth-like / zigzag-shaped extending sealing channel between the inner ring 9 and the outer ring 10, which is used to prevent the hydraulic agent / lubricant present in the interior 4 of the housing 2 from escaping to the environment during operation. In this embodiment, the disk regions 14a to 14c of the outer ring 10 are provided with a uniform diameter (inner diameter). In this embodiment, a total of three disk regions 14a to 14c are constructed, which are radially oriented and parallel to each other. However, it should be noted in this regard that the number of disk regions of the outer ring 10 is not set to three, so in other embodiments, more or fewer than three disk regions can of course also be used.

[0037] Furthermore, it can be seen that the outer ring 10 has a plurality of return holes 11 arranged in a circumferentially staggered / evenly distributed manner. The return holes 11 penetrate the outer ring 10 in the radial direction. The return holes 11 are implemented as through holes, for example. The return holes 11 are arranged in a manner that they are evenly spaced from each other circumferentially. The number of the return holes 11 is selected in such a way that the lubricant / oil / hydraulic agent can flow downward through the return holes 11 in any rotational position of the inner ring 9 or the shaft body 5.

[0038] The return holes 11 are arranged in the axial region between two axially adjacent disc regions 14b and 14c of the outer ring 10. The return holes 11 are arranged in / introduced into the axial region between the first disc region 14a of the outer ring 10 that is axially closest to the environment and the second disc region 14b of the outer ring 10 adjacent to this first disc region and facing the interior 4 of the housing 2.

[0039] All the return holes 11 are at the same height in the axial direction and are thus arranged along a line concentrically surrounding the rotation axis 21 / perpendicular to the plane of the rotation axis 21. All the return holes 11 communicate radially outwards with a fully circumferential annular groove 13, which in turn opens radially outwards.

[0040] On the circumferential region of the outer ring 10, preferably at the bottom side / lowest position of the labyrinth seal 8 (with respect to the installation position and the acting gravity), the return channel 12 is connected to the annular groove 13. The return channel 12 leads into the housing 2. Thus, the lubricant flowing out through the return holes 11 during operation is returned to the water tank of the hydraulic circuit through the return channel 12. It can be seen that the return channel 12 returns from the labyrinth seal 8 basically axially inclined in the direction of the interior 4 of the housing 2.

[0041] Furthermore, it should be noted that seals in the form of sealing rings 16a, 16b are distributed and inserted between the inner ring 9 and the shaft body 5 and between the outer ring 10 and the housing 2. Each of the sealing rings 16a, 16b schematically shown here is formed as an O-ring, for example. A first sealing ring 16a is inserted between the inner ring 9 and the shaft body 5. A second sealing ring 16b is inserted between the outer ring 10 and the housing 2. The second sealing ring 16b is arranged on the axially outward-facing (first) axial side 17a of the return holes 11. This prevents the hydraulic agent from flowing out to the environment.

[0042] In this regard, it should be noted that the sealing rings 16a and 16b can be directly used to fix the inner ring 9 or the outer ring 10 to the shaft body 5 or the housing 2, respectively. In addition, a fabric can be introduced complementarily. A combination of the labyrinth seal 8 and a grounding system can also be employed.

[0043] In other words, according to the present invention, a labyrinth seal 8 is realized, which is constructed in such a way that in the case where oil should enter the labyrinth, it flows back to the oil-free space through the drill holes, namely the return holes 11 and the return channel 12. The whole is realized by three plastic parts. The outer ring 10 consists of two parts, and the inner ring 9 is integrally formed. Fixing can be achieved by snap rings or hooks. The oil flows out through the transverse drill holes (return holes 11) and additional grooves (annular groove 13) in order to prevent "contact" caused by the rotor labyrinth.

[0044] Possible additional features: sealing rings 16a, 16b (e.g., O-rings) for sealing relative to the housing 2; can be fixed by these seals; a fabric can be introduced complementarily; can also be combined with a grounding system.

[0045] List of reference numerals

[0046] 1 Drive module

[0047] 2 Housing

[0048] 3 Opening

[0049] 4 Interior

[0050] 5 Shaft body

[0051] 6 First bearing

[0052] 7a First axial side of the bearing

[0053] 7b Second axial side of the bearing

[0054] 8 Labyrinth seal

[0055] 9 Inner ring

[0056] 10 Outer ring

[0057] 11 Return hole

[0058] 12 Return channel

[0059] 13 Annular groove

[0060] 14a First disk region of the inner ring

[0061] 14b Second disk region of the inner ring

[0062] 14c Third disk region of the inner ring

[0063] 15a First disk region of the outer ring

[0064] 15b Second disk region of the outer ring

[0065] 15c Third disk region of the outer ring

[0066] 15d Fourth disk region of the outer ring

[0067] 16a First sealing ring

[0068] 16b Second sealing ring

[0069] 17a First axial side of the return hole

[0070] 17b Second axial side of the return hole

[0071] 18 Tooth region

[0072] 19 Second bearing

[0073] 20 Wall portion

[0074] 21 Rotating shaft

[0075] 22 Basic section of the inner ring

[0076] 23a First arc segment

[0077] 23b Second arc segment

[0078] 24 Basic section of the outer ring

[0079] 25 Clearance

Claims

1. An electric drive module (1) for a vehicle, comprising a housing (2), a shaft (5) extending into an interior (4) of the housing (2) through an opening (3) of the housing (2), and a bearing (6) supporting the shaft (5) relative to the housing (2), wherein: On the side (7a) of the bearing (6) facing the environment of the housing (2), a labyrinth seal (8) is inserted in such a way that it acts between the housing (2) and the shaft body (6), wherein the labyrinth seal (8) has an inner ring (9) and an outer ring (10) which is arranged radially without contact with the inner ring (9), wherein the outer ring (10) also has a plurality of return holes (11) which penetrate radially through the outer ring, and the return holes (11) are connected to a return channel (12) introduced into the housing (2).

2. The driving module (1) according to claim 1, characterized in that: The return openings (11) are arranged axially at the same height and evenly distributed over the circumference.

3. The driving module (1) according to claim 1 or 2, characterized in that: The inner ring (9) is formed in one piece and / or the outer ring (10) is formed from multiple parts.

4. The driving module (1) according to any one of claims 1 to 3, characterized in that: The return hole (11) is in communication with an annular groove (13) of the outer ring (10) that opens radially outward.

5. The driving module (1) according to any one of claims 1 to 4, characterized in that: The inner ring (9) and the outer ring (10) are provided with a plurality of disk areas (14a, 14b, 14c, 15a, 15b, 15c, 15d) alternating in the axial direction.

6. The driving module (1) according to any one of claims 1 to 5, characterized in that: The outer ring (10) has at least two disk areas (14a, 14b, 14c) which are axially spaced apart from one another.

7. The driving module (1) according to claim 6, characterized in that: The return opening (11) is introduced into the outer ring (10) between a first disk region (14a) axially closest to the environment and a second disk region (14b) adjoining the first disk region.

8. The driving module (1) according to any one of claims 1 to 7, characterized in that: The inner ring (9) has at least two disk areas (15a, 15b, 15c, 15d) which are axially spaced apart from one another.

9. The driving module (1) according to any one of claims 1 to 8, characterized in that: A sealing ring (16a, 16b) is inserted between the inner ring (9) and the shaft body (5) and / or between the outer ring (10) and the housing (2).

10. The driving module (1) according to claim 1, characterized in that: The sealing ring (16b) inserted in an active manner between the outer ring (10) and the housing (2) is positioned on the side (17a) of the return opening (11) axially facing the environment.

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