Housing part

Abstract

The invention relates to a housing part (7) for a transmission of a motor vehicle. The housing part (7) comprises a first connecting flange (13), - the first connecting flange (13) is adapted to be attached to a support of the motor vehicle in order to attach the transmission to the motor vehicle, - the first connecting flange (13) has a freely extending end section (18), - the freely extending end section (18) has a first frontal support surface (21) for contacting the carrier and - the first frontal support surface (21) is dimensioned so large that a force exerted on the support of the motor vehicle deforms the support only elastically and not plastically.

Description

[0001] The invention relates to a housing part for a transmission of a motor vehicle.

[0002] It is known to mount a housing located on the output side of an engine / transmission assembly on a cross member of a vehicle frame. Until now, the diameters of the bolting points on the housing have been approximately cylindrical. If the cross member is too soft, edge supports at the bolting points can result in a conventional design.

[0003] US 5,174,541 A shows a mounting device with two fastening sections, one of which is connected to a transmission section of an engine / transmission assembly and the other to a frame member of a vehicle, wherein the fastening sections rotate relative to each other about an axis normal to a plane of inclination of the engine / transmission assembly while it is being mounted on the vehicle and during subsequent operation of the vehicle. A stationary cylindrical tubular sleeve surrounds a rubber insulator that can rotate within the sleeve. One of the fastening sections of the mounting device is connected to the rubber insulator and rotates with it, thereby varying the angular position of the engine / transmission assembly with respect to the vehicle.

[0004] DE 10 2020 124 436 A1 describes a housing for an electrical machine, which has at least one terminal arranged at a distance from an outer surface of the housing for screwably fastening the housing, as well as at least one rib connecting a contact surface of the terminal and the outer surface of the housing. The outer surface of the housing has a recess extending from the rib.

[0005] One object of the invention can be seen in providing a fastening technology that, in particular, avoids edge supports. This object is achieved by the subject matter of patent claim 1. Advantageous embodiments are the subject matter of the dependent claims, the following description, and the figures.

[0006] According to the present invention, a housing part is proposed. The housing part can be made, for example, from an aluminum material, in particular using an aluminum die-casting process. The housing part can accommodate components of a transmission, in particular an automatic transmission. The present disclosure provides a larger support surface for screw-on points of the housing part than in the prior art, in particular by enlarging a diameter in the support surface. This allows edge wear of the screw-on points to be reliably avoided.

[0007] In this context, according to the invention, a housing part for a transmission of a motor vehicle is provided. A motor vehicle is a vehicle powered by its own engine or drive system and capable of transporting people or cargo on roads or other drivable surfaces. Motor vehicles can include various types, such as cars (passenger cars), trucks (lorries), buses, motorcycles, etc. They are an essential part of the modern transportation system. A transmission is a mechanical device used to vary the speed and torque between a drive source (such as an engine) and a driven device (such as the wheels of a motor vehicle). It allows the selection and adjustment of gear ratios to optimally adapt the performance of the drive to the respective driving situation. A housing part is a part of a housing.A casing is a structural component of a mechanical system that serves to protect, enclose, or house other parts of the system. In the case of an automotive transmission, a casing part can be an outer panel or housing that surrounds and protects the transmission's internal components.

[0008] The housing part comprises a first connecting flange. A bolt-on point or connecting flange is a specific structural component of a housing part, particularly in the context of transmissions for motor vehicles. The connecting flange serves to connect the transmission to other parts of the vehicle frame or body, such as a cross member. The connecting flange is typically provided with threaded holes or other fastening devices to enable assembly by tightening screws or bolts. The use of connecting flanges ensures a firm and secure attachment of the transmission to the vehicle frame, which supports efficient power transmission and a stable vehicle structure. The housing part can comprise multiple connecting flanges. An embodiment with four connecting flanges is described below.The “first” connecting flange is then one of the four connecting flanges.

[0009] It is provided that the first connecting flange is designed to be fastened to a support of the motor vehicle in order to fasten the transmission to the motor vehicle. It is further provided that the first connecting flange has a freely extending end section. It is further provided that the freely extending end section has a first end-face bearing surface for contacting the support. It can also be provided that the first end-face bearing surface is dimensioned so large that a force exerted on the support of the motor vehicle only deforms the support elastically and not plastically. This results in a more uniform introduction of transverse forces into the cross member. In this context, the housing can in particular be designed such that part of the transverse force can be absorbed by the housing part. This makes it possible to avoid edge supports.

[0010] The inventors have discovered that surface pressure is not in the plastic range when the bearing surface is circular or annular, with an outer diameter of the bearing surface being at least 32 millimeters. In this context, one embodiment provides for the first end-face bearing surface to have an annular cross-section. The connecting flange has a central bore for receiving a screw or bolt. In the first end-face bearing surface, this leads to a central cutout that is surrounded by a ring that forms the effective bearing surface. This ring has an optimal ratio between circumference and area. Furthermore, it is provided that the annular cross-section has an outer diameter of at least 32 millimeters.As an alternative to the annular cross-section, oval or irregular geometries of the support surface can also be used if, for example, a different geometry results from a mold division.

[0011] To overcome these problems, it is proposed to provide the freely extending end section in an "elephant's foot design." The geometric shape of the elephant's foot is created by, on the one hand, making the first end-face contact surface as large in diameter as possible to reduce surface pressure. On the other hand, the inner section or cylindrical part is as small or thin as possible to minimize or at least reduce the risk of porosity. The background here is that, for example, with a 32 millimeter outer diameter of the contact surface, a cylindrical design of the inner section will result in material accumulations that can lead to porosity. Therefore, it is planned that only the lower area or the freely extending end section and its contact surface will be enlarged, but not the inner section of the first connecting flange. This results in the elephant's foot design.In this context, according to the invention, the first connecting flange has an inner section. Furthermore, the inner section is arranged closer to an output shaft in a radial direction than the freely extending end section. Furthermore, the invention is characterized in that the inner section has an annular cross-section. Furthermore, the inner section has a smaller outer diameter than the freely extending end section. This can prevent an increased risk of porosity. Furthermore, a design of the screwing points that is suitable for casting can be achieved. Another advantage is that a lighter cross member is possible overall because it does not have to be specially reinforced. In this context, a contribution is made to reducing the increase in weight.In particular, the proposed technology eliminates any weight gain or only minimal weight gain.

[0012] In particular, the housing part can have four of the connecting flanges described in this disclosure in order to ensure a particularly stable and durable attachment to the carrier of the motor vehicle. In particular, the connecting flanges or their bearing surfaces can be oriented in pairs such that corresponding contact surfaces of the carrier of the motor vehicle can be contacted. In this context, according to one embodiment, the housing part further comprises a second connecting flange, a third connecting flange and a fourth connecting flange. This embodiment is characterized in particular in that the first end-face bearing surface of the first connecting flange and a second end-face bearing surface of the second connecting flange extend in a first common plane.Furthermore, it is provided that a third end-face support surface of the third connecting flange and a fourth end-face support surface of the fourth connecting flange extend in a second common plane. Furthermore, this embodiment is characterized in that the first common plane and the second common plane extend at an angle to each other, corresponding to two support surfaces of the carrier.

[0013] The housing part can be used particularly advantageously on an output side of an automatic transmission. In this context, according to one embodiment, the transmission is an automatic transmission. The motor vehicle can be, in particular, a passenger car or a commercial vehicle such as a truck. Furthermore, it is provided that the housing part is arranged on an output side of the transmission. This embodiment is further characterized in that the housing part closes the transmission on its output side.

[0014] The automatic transmission can, in particular, be installed longitudinally in the motor vehicle, with the carrier being installed transversely in the motor vehicle ("cross member"). In this context, according to one embodiment, an output shaft of the transmission is arranged in a longitudinal direction of the motor vehicle. Furthermore, the carrier is arranged transversely to the longitudinal direction.

[0015] A length of the inner section of the first connecting flange can in particular be between 18 and 20 millimeters. A length of the freely extending end section of the first connecting flange can in particular be between 13 and 15 millimeters. In this context, according to one embodiment, it is provided that the inner section extends in the radial direction between 18 and 20 millimeters. Furthermore, it is provided that the freely extending end section extends in the radial direction between 13 and 15 millimeters. A width of the inner section of the first connecting flange can furthermore be in particular between 20 and 25 millimeters, for example 22 millimeters. In this context, according to one embodiment, it is provided that the inner section extends transversely to the radial direction between 20 and 25 millimeters.

[0016] Furthermore, it can advantageously be provided that the outer diameter increases starting from the inner section and reaches its maximum value within the freely extending end section. In this context, according to one embodiment, the outer diameter of the inner section increases in the radial direction towards the freely extending end section until it reaches a value of 32 millimeters in the first end-face support surface. This avoids abrupt transitions that could lead to stress peaks within the connecting flange. The increase in the outer diameter can take place continuously, i.e. along a straight line that runs in the outer surface of the inner section and the freely extending end section of the first connecting flange. Alternatively, the increase in the diameter can also take place along a curved surface, e.g. along an outwardly oriented curve.

[0017] In the following, embodiments of the invention are explained in more detail with reference to the schematic drawing, wherein identical or similar elements are provided with the same reference numerals. Fig. 1 is a plan view of a motor vehicle with a transmission attached to a support of the motor vehicle, Fig. 2 a perspective view of a first example of a housing part for the transmission according to Fig. 1, Fig. 3 Stresses (in megapascal MPa) in two frontal contact surfaces of connecting flanges of the housing part according to Fig. 2, Fig. 4 a perspective view of a second example of a housing part for the transmission according to Fig. 1, Fig. 5 an alternative perspective view of the housing part according to Fig. 4 in the area of ​​two connecting flanges, Fig. 6 Stresses (in megapascal MPa) in two frontal contact surfaces of two connecting flanges of the housing part according to Fig. 4, Fig. 7 a perspective view of a second example of a housing part for the transmission according to Fig. 1, Fig. 8 Stresses (in megapascal MPa) in two frontal contact surfaces of two connecting flanges of the housing part according to Fig. 7, Fig. 9 a schematic front view of a third example of a part of a housing part in the region of a first and second connecting flange and Fig. 10 a schematic rear view of the housing part according to Fig. 9.

[0018] Fig. 1 shows a motor vehicle 1. The motor vehicle 1 can be, for example, a passenger car or a commercial vehicle such as a truck. The motor vehicle 1 comprises an engine 2, which can be, for example, an internal combustion engine or an electric motor. The motor vehicle 1 also comprises a transmission 3, which can be, for example, an automatic transmission. The engine 2 can drive a front axle 4 and / or rear axle 5 of the motor vehicle 1 via the transmission 3 and other components not shown (such as cardan shafts and differential gears). At least one wheel 6 is mounted on each side of the front axle 4 and the rear axle 5.

[0019] The automatic transmission comprises a housing part 7 which, together with a further housing part 8, accommodates components of the transmission 3 (e.g. gear sets and shift elements not shown), closes off the transmission 3 to the outside and thereby protects said components. The housing part 7 is arranged on an output side 9 of the transmission 3. The further housing part 8 is arranged on a drive side 10 of the transmission 3. The drive side 10 faces the side on which the engine 2 is located. The output side 9 faces away from the side on which the engine 2 is located. On the output side 9, the transmission 3 has an output shaft 11. The output shaft 11 rotates about its longitudinal axis L11 and delivers an output torque which can be transmitted to the front axle 4 and / or the rear axle 5.

[0020] When the motor vehicle 1 is traveling forwards or backwards in a straight line, ie without turning the wheels, it moves in a longitudinal direction L1. The longitudinal axis L11 of the output shaft 11 can be collinear (as in the embodiment according to Fig. 1) or parallel to the longitudinal direction L1. The housing part 7 is fastened to a support 12 of the motor vehicle 1. The support 12 may belong to a frame of the motor vehicle 1 (not shown in detail). The support 12 may extend further in a transverse direction Q than in the longitudinal direction L1. The transverse direction Q runs transversely to the longitudinal direction L1 and in particular in a horizontal direction. In this case, the support 12 may be referred to as a "cross member".

[0021] Fig. 2 shows a known housing part 7. The housing part 7 comprises a first connecting flange 13, a second connecting flange 14, a third connecting flange 15 and a fourth connecting flange 16. The four connecting flanges 13 to 16 are in the example according to Fig. 2 are constructed similarly, ie they each have a cylindrical inner section 17 and a freely extending end section 18. In Fig. 2, for reasons of clarity, only the inner section 17 and the freely extending end section 18 of the first connecting flange 13 are provided with a reference symbol. The following primarily describes the first connecting flange 13, although the corresponding explanations also apply to the three other connecting flanges 14 to 16.

[0022] The inner section 17 and the free-running section run in a radial direction r which is not defined by Fig. 2 shown output shaft 11 (cf. Fig. 1). In the example after Fig. 2, the inner section 17 and the freely extending end section 18 each have an annular cross-section with the same outer diameter 19. The outer diameter 19 is in the Fig. 2, the diameter is 22 millimeters. The cross-section is annular with a central bore 20 for receiving, in particular, a screw 33 (not shown), which can in particular have a size of M8. By means of the screw 33, the housing part 7 can be fastened to the support 12 of the motor vehicle 1 (cf. Fig. 1, Fig. 9 and Fig. 10).

[0023] When the housing part 7 is attached to the support 12, a first end-face support surface 21 of the first connecting flange 13 contacts a corresponding contact surface of the support 12. The first end-face support surface 21 is arranged on the freely extending end section 18 and closes it off to the outside. This is what is meant by the term "end-face." Accordingly, the second connecting flange 14 also has a second end-face support surface 22, the third connecting flange 15 has a third end-face support surface 23, and the fourth connecting flange 16 has a fourth end-face support surface 24.

[0024] Fig. 2 shows, as an example for the four connecting flanges 13 to 16, stresses on the right within the second end-face support surface 22 of the second connecting flange 14 and stresses on the left within the third end-face support surface 23 of the third connecting flange 15. With the existing outer diameter 19 of 22 millimeters, the risk of porosity in the four connecting flanges 13 to 16 is relatively low, since relatively little material is accumulated. The weight of the four connecting flanges 13 to 16 is also correspondingly low. However, with the given outer diameter 19 of 22 millimeters, the stresses in the edges of the four support surfaces 21 to 24 reach very high values, particularly in an edge region 25. The stress values ​​within the edge region 25 can be so high that edge supports occur in the support surfaces 23 to 26 of the freely extending end sections 13 to 16.

[0025] Fig. 4 and Fig. 5 show a housing part 7 according to an embodiment of the present invention. The housing part 7 comprises a first connecting flange 13, a second connecting flange 14, a third connecting flange 15 and a fourth connecting flange 16. The four connecting flanges 13 to 16 are in the example according to Fig. 4 and Fig. 5 are constructed similarly, ie they each have a cylindrical inner section 17 and a freely extending end section 18. In Fig. 4, for reasons of clarity, only the inner section 17 and the freely extending end section 18 of the first connecting flange 13 are provided with a reference symbol. The following primarily describes the first connecting flange 13, although the corresponding explanations also apply analogously to the three other connecting flanges 14 to 16.

[0026] The inner section 17 and the free-running end section 18 extend in a radial direction r which is not defined by Fig. 4 and Fig. 5 shown output shaft 11 (cf. Fig. 1). In the example after Fig. 4 and Fig. 5, the inner section 17 and the freely extending end section 18 each have an annular cross-section with the same outer diameter 19. The outer diameter 19 is in the Fig. 4 and Fig. 5 shown example 32 millimeters, thus 10 millimeters more than in the embodiment according to Fig. 2. The cross-section is annular with a central bore 20 for receiving in particular a Fig. 5, which can in particular have the size M8. By means of the screw 33, the housing part 7 can be fastened to the support 12 of the motor vehicle 1 (cf. Fig. 1, Fig. 9 and Fig. 10).

[0027] Fig. Figure 6 shows, as an example, for the four connecting flanges 13 to 16, stresses within the second frontal support surface 22 of the second connecting flange 14 on the right and stresses within the third frontal support surface 23 of the third connecting flange 15 on the left. With the existing outer diameter 19 of 32 millimeters, the risk of porosity in the four connecting flanges 13 to 16 is relatively high, since relatively four material is accumulated. Fig. 5 illustrates a material accumulation 26. The weight of the four connecting flanges 13 to 16 is also correspondingly high. However, the stresses in the edges of the four support surfaces 21 to 24, given the outer diameter 19 of 32 millimeters, assume relatively moderate values, particularly in an edge region 25. The stress values ​​within the edge region 25 are so low that no edge supports occur in the support surfaces 23 to 26 of the freely extending end sections 13 to 16.

[0028] Fig. Figure 7 shows a housing part 7 according to a further embodiment of the present invention. The housing part 7 comprises a first connecting flange 13, a second connecting flange 14, a third connecting flange 15, and a fourth connecting flange 16. The four connecting flanges 13 to 16 are in the example according to Fig. 7 are similarly constructed, ie they each have an inner section 17 and a freely extending end section 18 in the form of an “elephant foot”. Fig. For the sake of clarity, only the inner section 17 and the freely extending end section 18 of the first connecting flange 13 are provided with a reference symbol in Figure 7. The following primarily describes the first connecting flange 13, although the corresponding explanations also apply to the three other connecting flanges 14 to 16.

[0029] The inner section 17 and the free-running section run in a radial direction r which is not defined by Fig. 7 shown output shaft 11 (cf. Fig. 1). The inner section 17 can, for example, have a length of approximately 20 millimeters. The freely extending end section 18 can, for example, have a length of approximately 15 millimeters. In the example according to Fig. 7, the inner section 17 and the freely extending end section 18 each have an annular cross-section. The outer diameter 19 is in the Fig. 7 shown example 32 millimeters within the free-running end section 18, thus 10 millimeters more than in the embodiment according to Fig. 2. The inner section 17 can have a material thickness of, for example, 22 millimeters. The cross-section is annular with a central bore 20 for receiving a non- Fig. 7 shown screw 33 (cf. Fig. 5), which can in particular have the dimension M8. The housing part 7 can be fastened to the support 12 of the motor vehicle 1 by means of the screw 33 (cf. Fig. 1, Fig. 9 and Fig. 10).

[0030] Within the inner section 17, the outer diameter 19 takes on a smaller value than in the freely extending end section 18. Therefore, the outer diameter within the inner section 17 is less than 32 millimeters. This prevents material accumulations as in the embodiment according to Fig. 4 and Fig. 5 is avoided, thus reducing the risk of porosity. Fig. In the embodiment shown in Figure 7, the outer diameter 19 increases from the inner section 17 to the freely extending end section 18, where it finally reaches a value of 32 millimeters at the first end-face support surface 21. The outer diameter 19 does not increase abruptly, but rather partially linearly, i.e., along a straight line, and partially along a curved line. Abrupt decreases or increases in the outer diameter 19 are thus avoided. This contributes to avoiding stress peaks within the first connecting flange 13.

[0031] Fig. Figure 8 shows, as an example for the four connecting flanges 13 to 16, stresses within the second end face 22 of the second connecting flange 14 on the right and stresses within the third end face 23 of the third connecting flange 15 on the left. The increase in the outer diameter 19 to 32 millimeters described above reduces the risk of porosity in the four connecting flanges 13 to 16 by preventing excessive material accumulation. The weight of the four connecting flanges 13 to 16 is also correspondingly moderate. The stresses in the edges of the four support surfaces 21 to 24 also assume relatively moderate values ​​for the given outer diameter 19 of 32 millimeters, particularly in an edge region 25. The stress values ​​are so low within the edge region 25 that no edge supports occur in the support surfaces 23 to 26 of the freely extending end sections 13 to 16.

[0032] Fig. 9 and Fig. 10 show a further example of a housing part 7 with four connecting flanges 13 to 16, by means of which the housing part 7 is fastened to the carrier 12 of the motor vehicle 1. As in the embodiment according to Fig. 7, the four connecting flanges 13 to 16 point to Fig. 9 and Fig. 10 each have an elephant foot design in the area of ​​the respective freely extending end section 18. The first connecting flange 13 has a first end-face support surface 21, the second connecting flange 14 has a second end-face support surface 22, the third connecting flange 15 has a third end-face support surface 23, and the fourth connecting flange 16 has a fourth end-face support surface 24. The first end-face support surface 21 and the second end-face support surface 22 lie in a first common plane 27, the third end-face support surface 23 and the fourth end-face support surface 24 lie in a second common plane 28.

[0033] The first common plane 27 and the second common plane 28 extend at an angle to each other. In the embodiment shown according to Fig. 9 and Fig.10, the first common plane 27 and the second common plane 28 are each inclined at the same contact angle 29 to a horizontal line 30. However, this is purely exemplary. Alternatively, the two common planes 27, 28 can also be inclined at different angles to the horizontal line 30. The first end-face support surface 21 and the fourth end-face support surface 24 diverge, i.e., they are directed away from one another and not toward one another. When fastened to the carrier 12, the first end-face support surface 21 and the fourth end-face support surface 24 each point laterally outwards with respect to the motor vehicle 1.

[0034] The first end-face support surface 21 rests against a first contact surface 31 of the carrier 12. The first contact surface 31 runs in the first common plane 27. The first contact surface 31 extends in the first common plane 27 to such an extent that both the first end-face support surface 21 and the second end-face support surface 22 can contact the first contact surface 31. Similarly, the fourth end-face support surface 24 rests against a second contact surface 32 of the carrier 12. The second contact surface 32 runs in the second common plane 28. The second contact surface 32 extends in the second common plane 28 to such an extent that both the third end-face support surface 23 and the fourth end-face support surface 24 can contact the second contact surface 32. Reference symbol L1 longitudinal direction L11 Longitudinal axis r radial direction Q transverse direction 1 motor vehicle 2 engines 3 gearboxes 4 front axle 5 Rear axle 6 wheel 7 Housing part 8 additional housing part 9 Output side 10 Drive side 11 Output shaft 12 carriers 13 first connecting flange 14 second connecting flange 15 third connecting flange 16 fourth connecting flange 17 inner section 18 free-running end section 19 outer diameter 20 holes 21 first frontal support surface 22 second frontal support surface 23 third frontal support surface 24 fourth frontal support surface 25 edge area 26 Material accumulation 27 first common level 28 second common level 29 installation angles 30 horizontal 31 first investment area 32 second contact surface 33 Screw

Claims

Housing part (7) for a transmission (3) of a motor vehicle (1), the housing part (7) comprising a first connecting flange (13), wherein - the first connecting flange (13) is designed to be fastened to a support (12) of the motor vehicle (1) in order to fasten the transmission (3) to the motor vehicle (1), - the first connecting flange (13) has a freely extending end section (18), - the freely extending end section (18) has a first end-face bearing surface (21) for contacting the support (12), wherein - the first connecting flange (13) has an inner section (17), and - the inner section (17) has an annular cross-section, characterized in that - the inner section (17) is arranged closer to an output shaft (11) in a radial direction (r) than the freely extending end section (18), and - the inner section (17) has a smaller outer diameter (19) than the freely extending tapered end section (18). Housing part (7) according to claim 1, wherein- the first end-side bearing surface (21) has an annular cross-section and- the annular cross-section has an outer diameter (19) of at least 32 millimeters. Housing part (7) according to one of the preceding claims, the housing part (7) further comprises - a second connecting flange (14), - a third connecting flange (15), - a fourth connecting flange (16), wherein - the first end-face support surface (21) of the first connecting flange (13) and a second end-face support surface (22) of the second connecting flange (14) extend in a first common plane (27), - a third end-face support surface (23) of the third connecting flange (15) and a fourth end-face support surface (24) of the fourth connecting flange (16) extend in a second common plane (28), and - the first common plane (27) and the second common plane (28) extend at an angle to one another, corresponding to two contact surfaces (31, 32) of the carrier (12). Housing part (7) according to one of the preceding claims, wherein- the transmission (3) is an automatic transmission,- the housing part (7) is arranged on an output side (9) of the transmission (3), and- the housing part (7) closes the transmission (3) on its output side (9). Housing part (7) according to claim 4, wherein- the output shaft (11) of the transmission (3) is arranged in a longitudinal direction (L1) of the motor vehicle (1) and- the carrier (12) is arranged transversely to the longitudinal direction (L1). Housing part (7) according to one of the preceding claims, wherein- the inner section (17) extends in the radial direction (r) between 18 and 20 millimeters and- the freely extending end section (18) extends in the radial direction (r) between 13 and 15 millimeters. Housing part (7) according to claim 6, wherein the inner portion (17) extends transversely to the radial direction (r) between 20 and 25 millimeters. Housing part (7) according to one of the preceding claims, wherein the outer diameter (19) of the inner portion (17) increases in the radial direction (r) towards the freely extending end portion (18) until it reaches a value of 32 millimeters in the first end-side bearing surface (21).

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