EP1786643A2

EP1786643A2 - Multipurpose powertrain mount with integral restrictor

Info

Publication number: EP1786643A2
Application number: EP05762758A
Authority: EP
Inventors: Jeff Bradshaw; Bernie Rice; Douglas Power
Original assignee: Cooper Standard Automotive Inc
Current assignee: Cooper Standard Automotive Inc
Priority date: 2004-06-24
Filing date: 2005-06-24
Publication date: 2007-05-23
Also published as: WO2006012217A2; JP2008507664A; CA2572261A1; KR20070026819A; WO2006012217A3

Abstract

The present disclosure relates to a vehicular powertrain mount assembly (A) comprising an integral restrictor for damping vibrations. The powertrain mount assembly (A) has an integral restrictor to control the excessive motion of a vehicular powertrain, support the weight of the powertrain and insulate powertrain noise and vibrations. The powertrain mount assembly (A) comprises a bracket member (10) including a first (12) and second portions (14) extending at an angle relative to one another. A restrictor bracket (50) is disposed in spaced relation to the bracket member and includes a base section (52). The bracket member (10) and restrictor bracket (50) are mechanically attached to either the powertrain member or the frame member of a vehicle. A restrictor flange (74) is integrally formed with one of the bracket member (10) and the restrictor bracket (50). An elastomeric isolator (El) is interposed between the bracket member (10) and restrictor bracket (50) for damping vibrations therebetween, and the restrictor flange (74) is preferably over-molded with the elastomeric isolator (El).

Description

MULTIPURPOSE POWERTRAIN MOUNT WITH INTEGRAL RESTRICTOR

Cross Reference to Related Applications

[0001] This application claims priority from U.S. Provisional Patent Application Serial No. 60/582,415 filed June 24, 2004, the disclosure of which is incorporated herein by reference.

Background of the Invention

[0002] The present disclosure generally relates to a mount assembly and, more particularly, is concerned with a multipurpose powertrain mount and vibration isolator assembly comprising a compact integral restrictor design that insulates vibrations, supports the weight of the powertrain, and controls excessive motion of the powertrain. The present invention can also be used as a development tool for engineering purposes to help optimize and tune a powertrain mounting system for improved isolation and performance.

[0003] Vehicular powertrain mount assemblies are generally known in the art and include engine mounts, transmission mounts, and the like. Numerous vibrations such as jounce vibrations, fore/aft vibrations, and torque and torque reaction vibrations are associated with an internal combustion engine mounted to an automotive vehicle. Resilient powertrain mounts have proved effective at isolating these vibrations from the passenger compartment. The powertrain mount assembly supports the weight of the powertrain and isolates noise and vibration such as jounce and roll control of the powertrain member relative to the frame. [0004] Typically, a conventional isolator or mount includes first and second bracket members that receive a volume of resilient material therebetween. Examples are shown and described in U.S. Patent Nos. 4,987,679; 5,031 ,873; and 6,708,793. The bracket members are normally stamped, cold-rolled steel parts which are mechanically attached to the powertrain member and the frame member of a vehicle, respectively. A typical resilient material is a rubber material capable of absorbing the vibration from the powertrain member and the jounce from the frame member such that these vehicle components are sufficiently isolated from each other. Preferred rubber materials include natural rubber, styrene-butadiene rubber, ethylene-propylene-diene-monomer rubber, and any other suitable elastomeric materials. The resilient elastomeric material is normally bonded to the metal brackets, for example, with a suitable solvent-based adhesive that is applied to the metal prior to the rubber molding process and then vulcanized with the rubber during a cure cycle.

[0005] Generally, the conventional powertrain mount fails to provide an interlock between the bracket members in the event the elastomeric isolator separates from the one of the bracket members. Moreover, the conventional powertrain mounts fail to control excessive powertrain motion. Further, the prior art does not allow for a two stage rate build up as forces are applied in eitherthe tensile and shear direction. Such an arrangement does not adequately address the different condition encountered during normal operating conditions, as well as during high load restriction where improved travel restriction is desired to control excessive motion. [0006] It will also be appreciated that different vehicle platforms require different powertrain mount configurations. Unfortunately, this encounters significant costs to alter the tooling. Therefore, a need exists for an improved design that can be easily converted/adapted between different platforms.

[0007] In light of the foregoing, it is evident that there is a need for a vehicular powertrain mount assembly that provides a solution to one or more of the noted deficiencies from which the prior art and/or conventional powertrain mounts have suffered. It is still more clear that an isolator or powertrain mount assembly providing a solution to at least some of the needs left by the prior art while providing a number of heretofore unrealized advantages thereover would represent an advance in the art.

Brief Description of the Invention

[0008] In an exemplary embodiment of the present disclosure, a vehicular powertrain mount assembly or isolator comprising an integral restrictor for damping vibrations is provided. The powertrain mount assembly comprises a first member and a second member disposed in spaced relation to the first member. The first member is mechanically attached one of the powertrain member and the vehicle, and the second member is mechanically attached to the other of the powertrain member and the vehicle. An elastomeric isolator is interposed between the first and second members for damping vibration therebetween. A restrictor assembly is operatively associated with the first and second members for controlling excessive relative motion therebetween. A portion of the restrictor assembly is integrally formed with one of the first and second members.

[0009] In accordance with a further aspect of the present disclosure, the powertrain mount assembly comprises a first member and a second member disposed in spaced relation to the first member. The first member includes first and second flanges which extend at an acute angle relative to one another. The first and second members are attached by mechanical means to either the powertrain member or the frame member of a vehicle. A restrictor assembly is operatively associated with the first and second members for controlling excessive relative motion therebetween. A portion of the restrictor assembly is integrally formed with one of the first and second members. An elastomeric isolator is interposed between the first and second members for damping vibrations therebetween, wherein the elastomeric isolator at least partially encompasses a portion of the restrictor assembly.

[0010] In accordance with another aspect of the present disclosure, the first member is a first bracket member including first and second portions extending at an acute angle relative to one another. A restrictor bracket is disposed in spaced relation to the first bracket member and includes a base section. The first bracket member is mechanically attached to one of the powertrain member and the frame member of the vehicle, and the restrictor bracket is mechanically attached to the other of the powertrain member and the vehicle frame member. A restrictor flange is integrally formed with the second bracket member operatively cooperates with the restrictor bracket.

[0011] In a preferred arrangement, the restrictor assembly included a flange over-molded with the elastomeric isolator.

[0012] The restrictor assembly further includes a pin extending from the restrictor bracket which is spaced from over-molded flange when mounted. The pin is adapted to engage the over-molded flange after a predetermined amount of travel - A -

and provides increased spring rate between the pin and restrictor flange and controls travel of the powertrain.

[0013] A primary benefit of the invention resides in the ability to provide an interlock between the first and second bracket members in the event the elastomeric isolator separates from the one of the bracket members.

[0014] Another benefit of the invention resides in the ability to provide a two stage rate buiid up as forces are applied in either the tensile and shear direction.

[0015] Still another benefit resides in the ability to control the excessive motion of a vehicular powertrain, support the weight of the powertrain and insulate powertrain noise and vibrations.

[0016] Yet another benefit is found in preventing metal to metal contact or "buzz" between the pin and the restrictor flange.

[0017] Still other non-limiting benefits and/or aspects of the disclosure will become apparent from reading and understanding the description of the preferred embodiments below.

Brief Description of the Drawings

[0018] The present invention may take physical form in certain parts and arrangements of parts, preferred embodiments of which will be described in detail in this specification and illustrated in the accompanying drawings which form a part of the invention.

[0019] FIGURE 1 shows a front perspective view of an assembled powertrain mount according to the present disclosure.

[0020] FIGURE 2 shows a rear perspective view of the assembled powertrain mount of FIGURE 2.

[0021] FIGURE 3 shows a front perspective view of a first bracket member according to the present disclosure.

[0022] FIGURE 4 shows a front perspective view of a partially assembled powertrain mount according to the present disclosure.

[0023] FIGURE 5 shows a rear perspective view of the partially assembled powertrain mount of FIGURE 4. [0024] FIGURES 6 and 7 show front perspective views of a restrictor bracket according to the present disclosure.

[0025] FIGURE 8 shows a perspective view of an alternate embodiment of the restrictor bracket of FIGURES 6 and 7.

[0026] FIGURE 9 shows a perspective view of an alternate embodiment of the restrictor bracket of FIGURE 8.

[0027] FIGURE 10 shows a perspective view of an assembled powertrain mount comprising the alternate embodiment of the restrictor bracket of FIGURE 9.

Detailed Description of the Invention

[0028] It should, of course, be understood that the description and drawings herein are merely illustrative and that various modifications and changes can be , made in the structures disclosed without departing from the spirit of the invention. Like numerals refer to like parts throughout the several views. [0029] A first embodiment of the present disclosure is shown in FIGURES 1 and 2. The powertrain mount assembly A generally includes a first bracket member, a restrictor bracket, a restrictor flange, an elastomeric isolator, and a second bracket member or adaptor bracket.

[0030] With additional reference to FIGURE 3, the first bracket member 10 preferably includes a first or lower portion 12 and a second or upper portion 14 extending in non-parallel relation, here at an acute angle relative to one another. Generally, a first end 16 of the upper portion is fixedly secured (e.g. welded) to the lower portion. The lower portion 12 includes a first flange 20 and a second flange or stem 22. The first flange extends downwardly and generally normal to lower portion. The second flange extends upwardly and at an acute angle relative to the lower portion. A second end 18 of the upper portion 14 is fixedly secured (e.g. welded) to an end of the second flange 22. Preferably, the lower and upper portions are metal structures, although as will be appreciated in accordance with the present invention, alternative materials including non-metallic materials can be used to form the lower and upper portions. The lower portion 12 further includes an aperture 24 (not shown) and mounting means, such as pressed in stud 26, for mechanically securing the powertrain mount assembly A to a vehicular frame member (not shown). [0031] Typically, the upper portion 14 extends at an angle relative to the lower portion 12, for example at approximately thirty degrees (30°). However, it will be appreciated by one skilled in the art that the angle between the lower and upper portions can be adjusted depending on the requirements needed for the end use by modifying the dimensions of the second flange 22. As such, only a stamped metal blank size of the lower portion 12 needs to be modified to make an angle change. Therefore, a design change that would normally cause high re-tooling costs now only requires a blank die change by accommodating an increase or decrease in the dimension of the second flange. As such, the stamping/forming dies used for forming the individual components of the powertrain mount assembly A will not be affected by a change to the angle.

[0032] As illustrated in FIGURES 4 and 5, secured to an outer surface of the upper portion 14 of the bracket member 10 is the elastomeric isolator El. The isolator is often an elastomer or rubber construction because of the inherent ability or elastic nature of the material to isolate and reduce noise and vibration from being transmitted therethrough. Rubber exhibits the desirable property that the more the rubber is compressed, the higher the stiffness. This rate build-up controls noise, vibration, and harshness associated with, for example, the vehicle environment. The elastomer is preferably mold bonded to the outer surface of the upper portion 14, although it will be appreciated that other bonding arrangements such as an adhesive bond, can be used without departing from the scope and intent of the present invention.

[0033] In a first embodiment of the present disclosure, and as illustrated in FIGURES 4 and 5, secured to the isolator El is a second bracket member or adaptor bracket 30. The adaptor bracket is selectively attached to an engine or transmission, i.e., the powertrain. The isolator is secured or bonded to the adaptor bracket, for example, by an adhesive bond. In this manner, the isolator is received between the first bracket member 10 and the second bracket member or adaptor bracket 30. The second bracket member has a lower stepped configuration 32 in the illustrated embodiment, although it will be appreciated that the conformation may vary depending on the surrounding structure that received the mount assembly. In addition, the second bracket member receives a mechanical fastener or stud 34 (FIGURES 4 and 5) therethrough that secures the second bracket member to the other of the powertrain or vehicle frame. In this instance, the second bracket member is secured to the powertrain.

[0034] With continued reference to FIGURES 4 and 5, and additional reference to FIGURE 6, the stepped region of the second bracket member receives a restrictor bracket 50 that includes a base section 52 having an aperture 54 adapted to receive the mounting fastener 34 for selectively securing the base section to the elastomeric isolator El and the adaptor bracket 50. The base section 52 further includes a first arm section 56 and a second arm section 58 extending from opposite ends thereof in this embodiment. The first and second arm sections each include an aperture 60 and are dimensioned to receive a pin member 64 therebetween. Opposite ends of the pin are peened to secure the pin in position. As shown in FIGURE 2, the , restrictor bracket 50 can also include a downwardly extending tab 66. The tab further restricts the movement of the restrictor flange relative to the elastomeric isolator and the adaptor second bracket member (Bernie, does it act as a stop ??). [0035] Referring again with particularity to FIGURE 3, and additionally to FIGURES 2, 4, and 5, integrally formed with the bracket member 10 is a restrictor flange 74. The restrictor flange is operatively associated with the first bracket member 10 and the second bracket member 50, via the restrictor bracket 30 and the pin 64, for controlling excessive relative motion therebetween. The restrictor flange 74 has a generally C-shaped contour defining a cavity 76 for receiving the pin member 64 therein. However, it will be appreciated by one skilled in the art that the contour of the restrictor flange 74 can be modified without departing from the scope and intent of the invention. For example, the restrictor flange can have an L-shaped contour and such variants are within the scope of the present disclosure. [0036] The isolator 50 further encompasses at least a portion of the restrictor flange 74 and an outer surface of the second flange or stem 22 of the lower portion 12. The restrictor flange is preferably over-molded in elastomer or rubber. This over-molding allows for a two stage rate build up as forces are applied, for example, in either tensile or shear directions. The integral curved restrictor design maximizes compressive travel while controlling tensile and shear directions of the mount. The integration of rubber to the curved metal restrictor creates a two stage progressive rate build up in the tensile and shear directions. This allows for better isolation during normal operating conditions, with improved travel restrictions as the restrictor is engaged during high load conditions. The two piece restrictor also facilitates the molding of the main rubber element El by allowing its addition to the mount assembly in a post-secondary operation. The curved portion of the metal at the end of the first bracket member is over-molded in rubber during molding of the elastomeric isolator El. The restrictor metals are assembled to the isolator portion of the mount in a secondary operation. This system allows the mount to be molded with fewer parts while allowing the addition of rubber snubbers to the restrictor in the same molding process. The use of the molded lower metal flange 74 to create a hook for the restrictor pin and the secondary restrictor assembly operation allows for easy molding of the isolator.

[0037] As noted above, the pin member 64 is received between the first and second arm sections 56, 58 of the restrictor bracket 50 and in the cavity 76 of the restrictor flange 74. The pin member is spaced from the restrictor flange when initially assembled. For example, there is preferably a five (5) millimeter clearance between the pin member 64 and the over-molded restrictor flange 74, however, alternate spacing can be used. The restrictor pin will not engage the restrictor flange for the first five (5) millimeters of travel. This allows for good isolation since only the spring rate of the isolator El will affect the powertrain (not shown) over this distance. However, as the travel of the pin member 64 exceeds the spacing, the pin member will engage the over-molded restrictor flange 74. When this occurs, the spring rate of the isolator El and the spring rate between the pin member and the restrictor flange both affect the travel of the powertrain mount A. The spring rate . achieved between the pin member 64 and the bracket member 10 will quickly increase for the distance traveled thereby controlling the travel of the powertrain. This over-mold rubber on the restrictor flange also prevents the buzz and metal clanking associated with uncovered restrictors.

[0038] In general, an elastomer or rubber can tolerate increasing levels of compressive stress under cyclic loading much better than it tolerates smaller amounts of tensile stress. Thus, by introducing the over-molded restrictor flange 30 and the resulting two stage rate build up, fatigue life of the powertrain mount assembly A can be enhanced.

[0039] Similar to the aforementioned embodiments, additional embodiments are shown in FIGURES 7-10. For example in FIGURE 7, additional contours can be formed or stamped into the restrictor bracket 50 for strength or desired rigidity. However, the reference numerals indicate that in substantially all other aspects, the contoured restrictor bracket of FIGURE 7 is substantially similar to that shown in the earlier figures.

[0040] In the embodiment of FIGURE 8, most of the structure and function is substantially identical, so that reference numerals with a single primed suffix (') refer to like components (e.g., restrictor bracket is referred to by reference numeral 50'), and new numerals identify new components. The primary distinctions relate to the restrictor bracket, adaptor bracket and pin member. Particularly, the restrictor bracket 30" and the pin member 64' are integrally formed in this arrangement. Preferably, the pin member is fixedly secured to the restrictor bracket 30' in a manner well known in the art (e.g. welding). The pin member 64' is circular in cross- section and has a general oval contour such that a portion of the pin member is received in the cavity 76 of the restrictor flange 74. In order to secure the restrictor bracket 50' to the restrictor flange 74, the pin member 64' is looped over the restrictor flange. The base section 32' includes at least one slot 78 for attachment and selective adjustment of the restrictor flange 30' to the second bracket member 30. This configuration simplifies assembly of the restrictor bracket 50' and pin member 64' into the cavity 76.

[0041] As shown in FIGURES 9 and 10, the functions of the restrictor bracket and the second bracket member are formed as one piece (bracket 80). The bracket 80 includes a base section 82 and a first and second arm sections 84, 86 extending from the base section. Adjacent to an end portion of the base section 82 is a mounting aperture 88 and slot 90 for receiving mounting means 52. The base section further includes an opening 92 for receiving a portion of the powertrain. It can be appreciated that by incorporating the one piece bracket 80 in the powertrain mount assembly A", the number of manufacturing and assembly steps has been reduced. [0042] With continued reference to FIGURE 9, the pin member 64" has a first section 100 fixedly secured to the bracket 80 in a manner well known in the art (e.g. welding or crimping) and a second section 102 extending generally normal to the first section. As shown in FIGURE 10, the second section of the pin member 64" is received in the cavity 76 of the restrictor flange 74. Accordingly, this configuration of the bracket 80 and pin member 64" provides an interlocking feature that allows the separate components to merge and function as a single component thereby resisting relative movement between the restrictor bracket 50, second bracket member 30 and pin member 64.

[0043] In summary, the manipulation of spring rate build-up and component fatigue characteristics is accomplished using a conventional powertrain mount incorporating a restrictor bracket and an over-molded restrictor flange assemblies of different designs. The economical aspect of the powertrain mount assembly A means that more options can also be made available within the constraints of a development budget. This highlights yet another feature of the invention wherein the ability to make changes to design later in the program can be achieved without impacting the launch schedule of the product.

[0044] The exemplary embodiment has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. For example, various other manufacturing steps may be employed or in a different sequence. Likewise, different materials may be used or alternative processes without departing from the present invention. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

Having thus described the invention, it is now claimed:

1. A mount assembly for damping vibrations comprising: a first member adapted for connection to an associated first component; a second member disposed in spaced relation to the first member and adapted for connection with an associated second component; an elastomeric isolator interposed between the first and second members for damping vibration therebetween; and a restrictor assembly operatively associated with the first and second members for controlling excessive relative motion therebetween, a portion of the restrictor assembly integrally formed with one of the first and second members.

2. The invention of claim 1 wherein the first member includes a first flange and a second flange extending at an acute angle relative to one another.

3. The invention of claim 1 wherein the second member includes a base section and first and second arm sections extending therefrom.

4. The invention of claim 1 wherein the restrictor assembly has a generally C- shaped contour on the first member defining a cavity for receiving a pin member therein.

5. The invention of claim 4 wherein the pin member is normally disposed in spaced relation from the C-shaped contour.

6. The invention of claim 4 wherein the pin member is received between the first and second arm sections of the second member.

7. The invention of claim 6 wherein the second member and the pin member are integrally formed.

8. The invention of claim 1 wherein an adaptor bracket is selectively secured to at least one of the second member and the elastomeric isolator.

9. The invention of claim 8 wherein the adaptor bracket and the second member are one-piece.

10. The invention of claim 1 wherein the elastomeric isolator is molded to a portion of the one of the first member and the restrictor assembly.

11. The invention of claim 1 wherein the elastomeric isolator at least partially encompasses a portion of the restrictor assembly.

12. A mount assembly assembly for damping vibrations comprising: a first member adapted for connection to an associated first component, the first member including a first and second flanges extending at an angle relative to one another; a second member disposed in spaced relation to the first member and adapted for connection with an associated second component; a restrictor assembly operatively associated with the first and second members for controlling excessive relative motion therebetween, a portion of the restrictor assembly integrally formed with one of the first and second members; and an elastomeric isolator interposed between the first and second members for damping vibrations therebetween, wherein the elastomeric isolator at least partially encompasses a portion of the restrictor assembly.

13. The invention of claim 12 wherein the second member includes a base section and first and second arm sections extending therefrom.

14. The invention of claim 12 wherein the restrictor assembly includes a C- shaped flange integrally formed with the first member.

15. The invention of claim 14 wherein the generally C-shaped flange defines a cavity for receiving a pin member therein.

16. The invention of claim 12 wherein the pin member is selectively secured to the second member. '

17. The invention of claim 12 wherein the pin member and the second member are integrally formed.

18. The invention of claim 12 wherein a bracket (adaptor bracket) is selectively secured to at least one of the second member and the elastomeric isolator.

19. The invention of claim 18 wherein the bracket and the second member are of one piece.

20. An powertrain mount assembly for damping vibrations comprising: a bracket member adapted for connection to an associated first component, the bracket member including a first and second portions extending at an acute angle relative to one another; a restrictor bracket disposed in spaced relation to the bracket member and adapted for connection with an associated second component, the restrictor bracket including a base section; a restrictor flange integrally formed with one of the bracket member and the restrictor bracket; an elastomeric isolator interposed between the bracket member and restrictor bracket for damping vibrations therebetween; and wherein the restrictor flange is over-molded with the elastomeric isolator.

21. The invention of claim 20 wherein the restrictor flange has a generally C- shaped contour on a portion thereof defining a cavity for receiving a pin member therein.

22. The invention of claim 21 wherein the pin member is generally spaced from the restrictor flange.

23. The invention of claim 20 wherein the pin member is selectively secured to the restrictor flange.

24. The invention of claim 20 wherein an adaptor bracket is selectively secured to at least one of the restrictor bracket and the elastomeric isolator.

25. The invention of claim 24 wherein the adaptor bracket and the restrictor bracket are of one piece.