BRACKET FOR SUPPORTING AN ELECTRIC MOTOR AND METHOD FOR MANUFACTURING SUCH A BRACKET

Abstract

The invention relates to a bracket for supporting an electric motor on a chassis of a vehicle. The bracket includes a first half shell defining a first half space and a second half shell defining a second half space. In embodiments, the first half shell and the second half shell are made from a plastic material, which may in particular comprise a polymer material. In embodiments, the first half shell and the second half shell are fixed to each other, such as by welding, such that the first half shell and the second half shell define a cavity within the bracket that includes the first half space and the second half space.

Claims

1.-15. (canceled)

16. A bracket for supporting an electric motor on a chassis of a vehicle, the bracket comprising: a first half shell defining a first half space, and a second half shell defining a second half space, wherein the first half shell and the second half shell are comprised of a plastic material or a polymer material; the first half shell and the second half shell are fixed to each other, such that the first half shell and the second half shell define a cavity within the bracket; and the cavity includes the first half space and the second half space.

17. The bracket of claim 16, wherein the first half shell and the second half shell are fixed to each other by welding.

18. The bracket of claim 16, wherein the first half shell and/or the second half shell are reinforced by ribs.

19. The bracket of claim 18, wherein the ribs are formed as one piece with the first half shell and/or the second half shell.

20. The bracket of claim 16, including a damper provided in the cavity.

21. The bracket of claim 20, wherein the damper comprises an oscillating mass and a first resilient member attached to the bracket and the oscillating mass.

22. The bracket of claim 21, wherein the first resilient member is made from an elastic material, and the first resilient member comprises a layer which surrounds the oscillating mass.

23. The bracket of claim 22, wherein the first resilient member is arranged between the oscillating mass and a damper wall which is formed as one piece with the first half shell and/or the second half shell.

24. The bracket according to claim 16, including at least one isolation bushing for attaching the electric motor to the bracket, wherein the isolation bushing comprises a body made from a rigid material to be connected to the electric motor and a second resilient member surrounding the body.

25. The bracket according to claim 24, wherein the second resilient member is arranged between the body and an inner surface of a first opening in the bracket.

26. The bracket according to claim 16, including at least one attachment bushing for attaching the bracket to the chassis, wherein the bracket comprises a second opening which includes protrusions arranged at axial ends of the second opening and extending into the second opening for positively locking the attachment bushing into the second opening in connection with fixing the first half shell to the second half shell.

27. The bracket according to claim 26, wherein the at least one attachment bushing comprises a plastic sleeve configured to be connected to the chassis and a rubber member surrounding the sleeve.

28. The bracket of claim 26, including at least two attachment bushings, each arranged in the respective second openings.

29. The bracket of claim 28, wherein the at least two attachment bushings differ in their shape and/or material.

30. The bracket of claim 28, wherein at least one attachment bushing comprises at least one arm inserted into a radially extending recess of the second opening, and the at least two attachment bushings differ in the orientation of the at least one arm.

31. The bracket according to claim 16, including an acoustic insulation cover shaped to surround the electric motor, wherein the acoustic insulation cover is fixedly attached to the bracket.

32. The bracket according to claim 31, wherein the acoustic insulation cover includes a first insulation half shell and a second insulation half shell, wherein the first insulation half shell and the first half shell are a one-piece unitary component.

33. The bracket of claim 31, wherein the acoustic insulation cover includes an attachment portion for attaching the acoustic insulation cover to the chassis and/or to the electric motor, and the attachment portion includes an isolation bushing and/or an attachment bushing.

34. A method for manufacturing a bracket for supporting an electric motor on a chassis of a vehicle, the method comprising: a) making a first half shell defining a first half space and a second half shell defining a second half space, wherein the first half shell and the second half shell are made from a plastic material, and b) fixing the first half shell to the second half shell, such that the first half shell and the second half shell define a cavity within the bracket including the first half space and the second half space.

35. The method of claim 34, wherein step a) includes manufacturing a first resilient member of a damper together with the second half shell by means of a dual injection process, and attaching an oscillating mass of the damper to the first resilient member.

36. The method of claim 34, wherein step a) includes providing at least one first opening in the first half shell and the second half shell, wherein an inner surface of the first opening is covered by a second resilient member, and wherein the second resilient member and the second half shell are manufactured in a dual injection process.

37. The method of claim 34, wherein, prior to step b), at least one attachment bushing for attaching the bracket to the chassis is inserted into a portion of a second opening which is arranged in the first half shell and/or the second half shell, and wherein the second opening includes protrusions arranged at axial ends of the second opening and extending into the second opening for positively locking the attachment bushing into the second opening in connection with fixing the first half shell to the second half shell.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0095] Preferred embodiments of the invention will be discussed in conjunction with the accompanying drawings.

[0096] FIG. 1 shows a perspective view of a first embodiment of a bracket;

[0097] FIG. 2 shows an exploded view of the bracket of FIG. 1;

[0098] FIG. 3 shows a partly assembled view of the bracket of FIG. 1;

[0099] FIG. 4 shows a cross-sectional view of the bracket of FIG. 1;

[0100] FIG. 5 shows a cross-sectional view of an attachment bushing of the bracket of FIG. 1;

[0101] FIG. 6 shows an explosive view of a first half shell of a second embodiment of a bracket having an acoustic insulation cover;

[0102] FIG. 7 shows a perspective view of an assembled configuration of the components of FIG. 6;

[0103] FIG. 8 shows a side view of the components of FIG. 7; and

[0104] FIG. 9 shows a bottom view of a first insulation half shell of the acoustic insulation cover of FIG. 6.

DETAILED DESCRIPTION

[0105] FIG. 1 shows a perspective view of a bracket 10 which is intended to be used for attaching an electric motor (not shown) to a chassis of a vehicle (not shown).

[0106] The bracket 10 comprises a first half shell 12 and a second half shell 14. The first half shell 12 and the second half shell 14 are preferably made from the same plastic material, preferably a glass fiber-reinforced polymer material, a thermoplastic material optionally reinforced with short glass fibers, or a thermoplastic material optionally reinforced with continuous fibers. The first half shell 12 comprises a first outer surface 16, while the second half shell 14 comprises a second outer surface 18. Upon attachment of the first half shell 14 to the second half shell 14, the outer surface of the bracket 10 is defined by the first outer surface 16 and the second outer surface 18.

[0107] As visible from FIGS. 2, 3 and 4, the first outer surface 16 of the first half shell 12 defines a first half space 20, while the second outer surface 18 of the second half shell 14 defines a second half space 22. Consequently, the bracket 10 includes a cavity which is constituted by the first half space 20 and the second half space 22. The first half space 20 as well as the second half space 22 are open at a plane which is directed to the respective other of the first half shell 12 and the second half shell 14.

[0108] The respective planes are defined and surrounded by a contact area 24. The first half shell 12 and the second half shell 14 are fixed to each other at the contact area 24, preferably by hot gas welding. The contact area 24 may be have the shape of a line (as shown in the FIGS. 2, 3 and 4) or of a strip. The contact area 24 may be end face of the first half shell 12 and/or the second half shell 14.

[0109] The first half shell 12 and/or the second half shell 14 comprise a plurality of ribs 26. The ribs 26 may extend along straight lines. The ribs 26 protrude from the first outer surface 16 and/or the second outer surface 18 into the first half space 20 and the second half space 22, respectively. The depth of the ribs 26 is such that they do not protrude from the plane defined by the contact area 24. The ribs 26 may be a unitary piece with the first half shell 12 and/or the second half shell 14.

[0110] The number, arrangement, and extension of the ribs 26 is such that the first half shell 12 and/or the second half shell 14 is reinforced. Due to the arrangement of the ribs 26, the bracket 10 is capable of supporting the weight of the electric motor. Furthermore, the manufacturing of the bracket 10 does not require additional screws or bolts, since the bracket 10 is made of the first half shell 12 and the second half shell 14 which are fixed to each other, preferably by welding.

[0111] The bracket 10 optionally comprises a damper 28. As particularly visible from FIG. 2, the damper 28 comprises an oscillating mass 30 and a first resilient member 32. The damper 28 is preferably provided within the cavity of the bracket 10. The oscillating mass 30 is attached to the bracket 10 by means of the first resilient member 32. Consequently, the oscillating mass 30 may oscillate with regard to the bracket 10. The damper 28 is provided at that position of the bracket 10 which shows the highest amplitude of the eigenmode oscillation of the bracket 10. This position may be computed or determined by a testing routine. The damper 28 is provided for reducing the eigenvibration of the bracket 10 or for shifting the frequency of the eigenmode of the oscillation the bracket 10.

[0112] The first resilient member 32 may comprise a first part 34 and a second part 36 separate from the first part 34. The oscillating mass 30 may be positively locked within the bracket 10. The first resilient member 32 may comprise a layer which surrounds the oscillating mass 30. For example, the first part 34 surrounds the oscillating mass 30 from five sides. The second part 36 of the first resilient member 32 may cover the oscillating mass 30 at the sixth side of the oscillating member 30.

[0113] The oscillating member 30 may be manufactured from a material which is heavier than the material of the bracket 10. For example, the oscillating mass 30 may be manufactured from metal. Since the first resilient member 32 completely surrounds the oscillating mass 30, the oscillating mass 30 may oscillate in any direction, while providing damping/absorbing characteristics.

[0114] The oscillating mass 30 may be fixed to the first resilient member 32 by bonding. However, it is preferred that the oscillating mass 30 is positively locked within the first resilient member 32. The damper 28 may be attached to the bracket 10 by adhesion or other means. It is also possible that the damper 28 is alternatively or additionally positively locked within the bracket 10.

[0115] For example, the second half shell 14 comprises a damper wall 38 and/or the first half shell 12 comprises a pocket 40. A bottom of the pocket 40 as well as the damper wall 38 define a space in which the damper 30 is positively locked. The damper wall 38 may be provided by the ribs 26. In the present case, the damper wall 38 intersects a rib 26. The damper wall 38 may have the same shape as the ribs 26. The pocket 40 may be omitted; the first outer surface 16 may act as a wall for positively locking the damper 28 in the damper wall 38.

[0116] The first part 34 of the first resilient member 32 may be simultaneously manufactured in a dual injection process with the second half shell 14. After manufacturing of the second half shell 14 and the first part 34 of the first resilient member 32, the oscillating mass 30 may be inserted into the first part 34 of the first resilient member 32. Subsequently, the second part 36 of the first resilient member 32 is placed on the that side of the oscillating member 30, upon which the first half shell 12 is attached to the second half shell 14, such that the bottom of the pocket 40 presses the second part 36 of the first resilient member 32 against the oscillating mass 30.

[0117] It is possible that the second part 36 of the first resilient member 32 is attached, for example bonded, to the bottom of the pocket 40. It is also possible that that the second part 36 of the first resilient member 32 is manufactured in a dual injection process of the first half shell 12. The first resilient member 32 may be made from a thermoplastic elastomer (TPE).

[0118] The bracket 10 optionally comprises at least one isolation bushing 42. In the present embodiment, two isolation bushings 42 are provided. The isolation bushing 42 provides a connection of the bracket 10 to the electric motor. The isolation bushing 42 may comprise a body 44 and a second resilient member 46. The body 44 can include an elongated member which may be made from a metal material or a rigid plastic material. The body 44 may comprise a through-hole in its axial direction for inserting a screw or bolt for attaching the electric motor to the bracket 10.

[0119] It is possible that the body 44 protrudes from the bracket 10 for attaching the electric motor. The body 44 may have a star-shaped outer surface in a cross-sectional view. However, other shapes of the outer surface in a cross-sectional view are possible.

[0120] The second resilient member 46 is formed as a layer between the body 44 and a first opening 48 of the bracket 10. The second resilient member 46 may also be made from TPE and preferably is manufactured in a dual injection process with the first half shell 12 and/or the second half shell 14. In particular, the first opening 48 arranged in the second half shell 14 protrudes from the second half space 22 towards the first half shell 12. Therefore, an inner surface of the first opening 48 is mostly or exclusively arranged at the second half shell 14, such that it is possible to completely manufacture the second resilient member 46 in a dual injection process with the second half shell 14. The first half shell 12 may only comprise a hole which allows to insert the isolation bushing 42, in particular the body 44.

[0121] The ribs 26 may originate from the first opening 48 in order to strengthen the first openings 48, as the weight of the electric motor is introduced into the bracket 10 by the first opening 48. The body 44 may be inserted into the second resilient member 46 which is already arranged in the first opening 48. This means that the body 44 is inserted in a subsequent step after the manufacturing of the second half shell 14 and the second resilient member 46.

[0122] The bracket 10 optionally comprises an attachment bushing 50. In the present embodiment, two attachment bushings 50 are provided. The attachment bushings 50 allow the attachment of the bracket 10 to the chassis.

[0123] The attachment bushing 50 may comprise a sleeve 52 and a rubber member 54. It is also possible that the attachment bushing 50 also includes an outer sleeve 56. The sleeve 52 is an elongated member which may include a through-hole along its axial extension. The through-hole is provided for inserting a bolt or a screw for attaching the bracket 10 to the chassis. The sleeve 52 may be manufactured from a metal or a plastic material.

[0124] The rubber member 54 is made from a resilient material, in particular a rubber material. The rubber member 54 is fixed to the sleeve 52, for example by vulcanization. As best seen in FIG. 4, the rubber member 54 comprises at least one arm 58, in the particular embodiment four arms 58. The rubber member 54 may completely surround the sleeve 52 in the circumferential direction, whereby the arms 58 protrude from that part of the rubber member 54 which is attached to the sleeve 52.

[0125] The outer sleeve 56 may be made from the same material as the sleeve 52, in particular a plastic material. The outer sleeve 56 surrounds the rubber member 54. Parts of the rubber member 54 may solely be attached to the outer sleeve 56, in particular in the areas between the arms 58. The tip end of the arms 58 may be attached to the outer sleeve 52. The outer sleeve 56 is provided for better inserting the attachment bushings 50 into a second opening 60 of the bracket 10.

[0126] The bracket 10 has in the shown embodiment two second openings 60. The second opening 60 is provided at both the first half shell 12 and the second half shell 14. However, the entire inner surface of the second opening 60 is solely provided at the second half shell 14. The first half shell 12 may exhibit a reduced thickness around the second opening 60 such that the second opening at the first half shell 12 may solely be a through-hole. It is also possible that the inner surface of the second opening 60 is provided by the first half shell 12 and the second half shell 14.

[0127] The inner surface of the second opening 60 comprises several recesses 62 which are provided for receiving the arms 58 of the attachment bushing 50. The second opening 60 is provided with protrusions 64 at its axial ends. As better seen in FIG. 5, the protrusions 64 radially extend from the inner surface of the second opening 60 inwards. As the inner surface of the second opening 60 is solely provided with the second half shell 14 in one embodiment, the second opening 60 of the first half shell 12 solely includes the protrusion 64.

[0128] The protrusion 64 may be configured as a rib extending over the whole inner circumference of the second opening 60. However, it is possible that the protrusion 64 is provided by a plurality of protrusions arranged at the second opening 60. As visible from FIG. 5, the protrusions 64 are arranged at the axial ends of the second opening 60. The protrusions 64 protrude from the inner surface of the second opening 60 radially inwards at such a length that the attachment bushing 50 is positively locked within the second opening 60 of the bracket 10 between the protrusions 64.

[0129] The second opening 60 of the second half shell 14 may be provided by a bushing wall 66 which may be configured similar to the ribs 26. The bushing wall 66 may be reinforced by ribs 26, for example that ribs 26 originate or terminate from the second opening 60, i.e. the bushing wall 66. The bushing wall 66 may be a unitary piece with the second half shell 14. As discussed above, the entire bushing wall 66 may be provided by the second half shell 14.

[0130] The second opening 60 of the first half shell 12 may solely by a through-hole, whereby the protrusion 64 on the axial end at the first half shell 12 can be constituted by a reduced diameter of the through-hole (see FIG. 6). In particular, the inner diameter of the through-hole (second opening 60 at the first half shell 12) is less than the outer diameter of the attachment bushing 50.

[0131] The attachment bushing 50 may be manufactured in a separate manufacturing process. The attachment bushing 50 may be inserted into the second opening 60 of the second half shell 14. After that, the first half shell 12 is fixed to the second half shell 14, such that the attachment bushing 50 is positively locked in the second opening 60 by means of the protrusions 64. Consequently, no adhesion or further attachment means are necessary for fixing the attachment bushing 50 to the bracket 10.

[0132] A further embodiment of the bracket 10 is discussed in conjunction with FIGS. 6 to 9. The bracket 10 has a similar configuration as the bracket 10 described above except the following differences. Please not that FIGS. 6 to 9 only show the first half shell 12 of the bracket 10. The second half shell 14 (not shown in FIGS. 6 to 9) may be identical to the second half shell 14 of the embodiment shown in FIGS. 1 to 5.

[0133] The bracket 10 includes an acoustic insulation cover 68. In fact, two brackets 10 are attached to the acoustic insulation cover 68. The brackets 10 are fixedly attached to the acoustic insulation cover 68. The acoustic insulation cover 68 is configured and shaped for surrounding the electric motor (not shown in the figures). The acoustic insulation cover 68 is provided for reducing, damping, and/or canceling airborne noise having frequencies above 2000 Hz. The bracket 10 is provided for reducing, dampening and/or canceling structure-borne noise having frequencies below 2000 Hz.

[0134] The acoustic insulation cover 68 may be in contact with the electric motor or spaced apart thereto. It is also possible that the acoustic insulation cover 68 is partly in contact with the electric motor and partly spaced apart thereto. As visible from FIGS. 6 to 9, the acoustic insulation cover 68 is formed and shaped to follow the outer contour of the electric motor. In order to achieve good noise insulation capabilities, the acoustic insulation cover 68 is preferably shaped to completely surround the electric motor. However, as visible in FIGS. 6 to 9, the acoustic insulation cover 68 may include through-holes and/or openings which may be used to guide axles or wires from the electric motor through the acoustic insulation cover 68. Furthermore, ventilation holes may also be provided for releasing heat generated by the electric motor.

[0135] The acoustic insulation cover 68 comprises a first insulation half shell 70 and a second insulation half shell 72. The first insulation half shell 70 and/or the second insulation half shell 72 can include a supporting member 74 and an insulating member 76. In the embodiment shown in the figures, only the first insulation half shell 70 includes a supporting member 74 and an insulating member 76. The second insulation half shell 72 solely consists of the supporting member 74.

[0136] Each of the supporting members 74 provides stability and strength to the acoustic insulation cover 68. The supporting members 74 may be fabricated from a thermoplastic material reinforced with short glass fibers. The insulating member 76 may be made from polypropylene and is provided for reducing and damping airborne noise as well as structure-borne noise. In particular, the insulating member 76 is formed and shaped as the supporting member 74 of the first insulation half shell 70. The insulating member 76 may completely cover the outer surface (the surface not facing the electric motor) of the supporting member 74 of the first insulation half shell 70. The insulating member 76 may be fixed to the supporting member 74 by means of adhesion. As the insulating member 76 is of a material capable of damping vibrations, the insulating member 76 reduces the vibrations of the supporting member 74 and is capable of absorbing airborne noise generated by the electric motor.

[0137] The supporting member 74 of the first insulation half shell 70 is a unitary piece with the first half shell 12 of the bracket 10. The supporting member 74 may be made with the first half shell 12 of the bracket 10 in one injection molding process. This means that the acoustic insulation cover 68 is supported by the bracket 10, such that vibrations generated by the electric motor are damped by the bracket 10 and are not transmitted to the acoustic insulation cover 68.

[0138] The supporting members 74 of the first insulation half shell 70 and of the second insulation half shell 72 are preferably attached mechanically to each other. To this end, the supporting member 74 of the first insulation half shell 70 includes a plurality of tongues 78 protruding in the direction of the second insulation half shell 72. The tongues 78 include bores which are coaxially aligned with bores in the second insulation half shell 72 upon attaching the second insulation half shell 72 to the first insulation half shell 70 as seen in FIG. 7.

[0139] The acoustic insulation cover 68 may further comprise an attachment portion 80. The attachment portion 80 may be a unitary piece with the supporting member 74 of the first insulation half shell 70. The attachment portion 80 is provided for attaching the acoustic insulation cover 68 to the electric motor and/or to the chassis.

[0140] In the embodiment shown in FIGS. 6 to 9, the attachment portion 80 is configured to be connected to both the chassis as well as the electric motor. The attachment of the attachment portion 80 to the electric motor and the chassis is similar to the one of the brackets 10. The attachment portion 80 may include a first opening 48 in which the insulation bushing 42 can be inserted as, for example, shown in FIG. 9. The first opening 48 in conjunction with the isolation bushing 42 allows the attachment of the acoustic insulation cover 68 to the electric motor while simultaneously providing noise decoupling between the acoustic insulation cover 68 and the electric motor.

[0141] The second opening 60 of the attachment portion 80 allows to include the attachment bushing 50 not shown in FIGS. 6 to 9. In this way, the attachment portion 80 can be attached to the chassis, while being simultaneously decoupled from the chassis.

[0142] The attachment portion 80 may also include ribs 26 (see FIG. 9). The attachment portion 80 is also a hollow member reinforced by the ribs 26. However, in contrast to the bracket 10, the attachment portion 80 does not exhibit a two-part structure as the bracket 10, but is a unitary member.

[0143] Beneficial aspects of the bracket 10 will be discussed in the following. Due to the configuration of the bracket 10 as being made by two half shells 12, 14 potentially reinforced by ribs 26, the bracket 10 is lightweight while still providing sufficient strength for supporting the electric motor. The lightweight aspect of the bracket 10 is further provided by manufacturing the bracket 10 from a plastic material. The characteristics of the plastic material in conjunction with configuration of the bracket 10 as a hollow member reinforced by ribs 26 allows to dampen/absorb vibrations generated by the electric motor in a frequency range between 750 and 2000 Hz.

[0144] The damper 28 is capable of absorbing/dampening vibrations in the frequency range between 400 and 750 Hz. Since the first resilient member 32 of the damper 28 can be made in a dual injection process with the first half shell 12 and/or the second half shell 14, respectively, the manufacturing of the damper 28 is simplified.

[0145] The isolation bushing 42 provides a damping/absorbing characteristic in the frequency range between 100 and 400 Hz. To this end, the weight of the electric motor in conjunction with the stiffness of the second resilient member 46 provides the damping/absorbing characteristics. Here again, the manufacturing of the isolation bushing 42 is simplified by the dual injection process of the second half shell 14 and the second resilient member 46.

[0146] A damping/absorbing of the vibration generated by the electric motor in the frequency range between 1 Hz and 400 Hz is achieved by the attachment bushing 50. The attachment of the attachment bushing 50 to the bracket 10 is simple, since the bushing 50 is positively locked by attaching the first half shell 12 to the second half shell 14. Consequently, no additional means for attaching the attachment bushing 50 to the bracket 10 are necessary.

[0147] Overall, preferred embodiments of the bracket 10 provide a complete damping/absorption of vibrations generated by the electric motor over a frequency range between 1 Hz and 2000 Hz. Basically, all vibrations generated by the electric motor may be attenuated by the bracket 10 in its preferred embodiments. Furthermore, the assembly process of the bracket 10 as well as the optional components (damper 28, isolation bushing 42 and/or attachment bushing 50) can be simplified due to the half shell structure of the bracket 10.

[0148] The manufacturing process of the bracket 10 in its preferred embodiment is described in the following. The first half shell 12 is manufactured in a molding process, whereby preferably the second part 36 of the first resilient member 32 is simultaneously manufactured by a dual injection process. Similarly, the second half shell 14 is molded, whereby preferably the first resilient member 32 and second resilient member 46 are simultaneously molded in a dual injection process.

[0149] After the molding of the second half shell 14, the oscillating mass 30 of the damper 28 is inserted into the first part 34 of the first resilient member 32. Additionally, the body 44 of the isolation bushing 42 is inserted into the second resilient member 46. Finally, the attachment bushing 50 is inserted into the second opening 60.

[0150] After that, the first half shell 12 is fixed to the second half shell 14, preferably by hot gas welding. By the fixation of the first half shell 12 to the second half shell 14, the oscillating mass 30 is positively locked in the first resilient member 32, while the attachment bushing 50 is also positively locked in the second opening 60 due to the presence of the protrusions 64. This means, the assembly process of the bracket 10 does not require additional screws or other attachment means. This simplifies the attachment process and reduces the number of components.