GB2503649A

GB2503649A - A mounting device for resisting vibrations between an engine and a chassis of a motor vehicle

Info

Publication number: GB2503649A
Application number: GB201210636A
Authority: GB
Inventors: Martin James Spencer
Original assignee: DTR VMS Ltd
Current assignee: DTR VMS Ltd
Priority date: 2012-06-14
Filing date: 2012-06-14
Publication date: 2014-01-08
Anticipated expiration: 2032-06-14
Also published as: GB201210636D0; GB2503649B

Abstract

When a mounting device 10 comprising first and second anchor parts 16, 18 interconnected by a deformable wall is fitted into an aperture in a mounting structure 40, it is desirable to provide a snubber between the mounting structure 40 and a bracket 14 to which the mounting device will be connected. To form that snubber, a deformable flap is formed integrally with the deformable wall, the flap 22, 26 being secured to one of the anchor parts 10 in a stowage position during mounting of the other anchor part 18 in the mounting structure 40, and subsequently being released from that one anchor part 16 and deformed to an operative position in which the flap 22, 26 overlies part of the surface of the mounting structure 40 adjacent to the aperture.

Description

MOUNTING DEVICE

The present invention relates to a mounting device for resisting vibrations between two components, such as the engine and chassis of a vehicle.

In such a mounting device, two anchor parts are connected by resilient material, such as rubber. One anchor part is attached to one component of the vibrating machinery, and the other anchor part attached to another component. As the two components vibrate relative to each other, the resilient material is deformed and thus forces are applied which resist the vibration.

More complicated mounting devices are known, such as the mounting devices which have chambers containing hydraulic fluid, the relative movement of the anchor parts and the deformation of the resilient material interconnecting them causing fluid to move between the chambers, creating a damping action. Such hydraulically damped mounting devices generally involve chambers connected by a passageway, as such a passageway improves the damping action as the fluid flows through its restrained path.

The present invention is applicable to both hydraulically damped mounting devices, and more simple mounting devices, with no hydraulic fluid.

EP-A-O1154l7 and EP-A-0172700 discuss two different types of hydraulically damped mounting devices for damping vibration between two parts of a piece of machinery, e.g. a car engine and a chassis. EP-A-0ll54l7 disclosed various "cup and boss" type of mounting devices, in which a "boss", forming a first anchor part to which one of the pieces of machinery is connected, is itself connected via a deformable (normally resilient) wall to the mouth of a "cup", which is attached to the other piece of machinery and forms a second anchor part. The cup and the resilient wall then define a working chamber for hydraulic fluid, which is connected to a compensation chamber by a passageway (usually elongate) which provided the damping orifice. The compensation chamber is separated from the working chamber by a riqid partition, and a flexible diaphragm is in direct contact with the hydraulic fluid and, together with the partition, forms a gas pocket.

In EP-A-0l72700 the mounting devices disclosed are of the "bush" type. En this type of mounting device, the anchor part for one part of the vibrating machinery is in the form of a hollow sleeve with the other anchor part in the form of a rod or tube extending approximately centrally and coaxially of the sleeve. The rod or tube forms a first anchor part and the sleeve forming a second anchor part. In EP-A-0l72700 the tubular anchor part is connected to the sleeve by resilient walls, which define one of the chambers in the sleeve. The chamber is connected via a-passageway to a second chamber bounded at least in part by a bellows wall which is effectively freely deformable so that it can compensate for fluid movement through the passageway without itself resisting that fluid movement.

In the hydraulically damped mounting devices disclosed in the specifications discussed above, there is a single passageway. It is also known, from other hydraulically damped mounting devices, to provide a plurality of S independent passageways linking the chambers for hydraulic fluid.

In EP-A-01l5417, there is a single diaphragm, which is configured to give a specific influence on the vibration characteristics of th? hydraulically damped mounting device. Those characteristics depend on the stiffness of the diaphragm, by which is meant the change in applied pressure needed to cause unit change in the volume displaced by the diaphragm. Furthermore, the surface of the diaphragm which is in contact with the fluid in the working chamber may be covered by a snubber plate, with openings therein for fluid communication therethrough between the upper surface of the diaphragm and the rest of the working chamber, and the size of those openings also affects the characteristics of the mount.

In GB-A-2282430, a mounting device is disclosed of the "cup and boss" type, with two diaphragms. The two diaphragms are arranged to have different characteristics, such as different stiffnesses or different effective stiffnesses, due to the shape of the openings by which fluid reaches those diaphragm parts from the working chamber. GB-A-2282430 also discloses that either or both of the diaphragms may be convoluted.

It is also known to provide an additional passageway to link the working chamber with another hydraulic chamber, separate from the compensation chamber, the additional passageway having a lower fluid resistance than the passageway between the working and compensation chambers.

In US5180148, a passage is formed between a pressure receiving chamber and a second equilibrium chamber. The passage is normally closed, and is held closed by the action of an elastic dish member which bears against a diaphragm via a thin rigid disk. The passage can be opened by application of a vacuum on the side of the elastic dish member not bearing against the diaphragm, so that the elastic dish member is separated from the diaphragm.

In US6017024, a passage is formed between a primary fluid chamber and an auxiliary fluid chamber. The passage is normally held closed by the action of a tensile spring, which bears against a circular metal disk. The metal disk is movable relative to the passage by flexing of a surrounding annular rubber member. This movement is controlled by control of the pressure in a vacuum chamber underneath the metal disk.

In GB-A-229l691, the arrangement disclosed in EF-A- 0172700 is modified by providing a bypass channel from the working chamber to the compensation chamber. Under normal operating conditions, that bypass channel 0 closed by part of the bellows wall bounding the compensation chamber. At high pressures, however, the bellows wall deforms to open the bypass channel, thereby permitting fluid from the working chamber to pass directly into the compensation chamber without having to pass through the full length of the passageway.

In both EP-A-0172700 and GB-A-229l691, the resilient walls extends generally axially along the interior of the mount. Those walls therefore formed axially elongate blocks of e.g. rubber material which are configured to achieve the desired static spring requirements. The material of the block is deformed primarily in shear, to give maximum durability. As the resilient walls also form walls of the working chamber, the axial ends of the working chamber are closed with material being integral with the resilient walls. In practice, however, the spring effect of those ends walls is small, so that the spring characteristic of the mount could be determined by the axially extending resilient walls.

CB-A-2322427 departs from this, by locating the resilient walls at axially spaced apart locations, unlike the arrangements in EE-A-0172700 and GB-A-2291691, in which the main spring effect is provided by axially extending, circuruferentially spaced, resilient walls. The resilient walls of GB-A-2322427 thus defined an enclosed space within the sleeve, which extends circumferentially around the central anchor part, which space is axially bounded by the resilient walls.

It is then necessary to divide that space into two chambers, and connect those two chambers with a passageway, to form the hydraulic mounting device of the bush type. To provide that division, GB-A-2322472 proposes that axially extending walls extend between the central anchor part and the sleeve. Unlike the axially extending walls of the known arrangements, those walls do not need to provide a spring effect, since the spring effect is provided by the axially spaced resilient walls.

Therefore, it is not necessary for those axially extending walls to be bonded to the sleeve and/or central anchor part. Instead, they made abutting, un-bonded, contact.

This permits a bypass to be formed between the chambers without the need for a separate bypass channel, as in GB-A-229l691. By suitably selecting the abutment force of the axial walls against the sleeve and/or central anchor part, a pressure-sensitive seal is achieved. For pressures below a suitable level, the integrity of that seal is achieved by the force of abutment. For *higher pressures, however, the seal is broken, thereby providing a path around the axial walls between the two chambers.

Normally, when either the hydraulically damped, or the more simple mounting devices discussed above are fitted to the pieces of machinery are to vibrate, the second anchor point is mounted in a mounting structure, which is then secured to one of the pieces of machinery, and the first mounting part is then connected to a bracket or similar structure, which is to be connected to another piece of machinery. In such an arrangement, it is important that there is no direct contact between the mounting structure and the bracket. Therefore, it has been considered to provide at least one deforrnable, preferably resilient, member on the mounting structure, which overlies part of the surface of that mounting structure which, in use, will be aligned with a part of the bracket, and which acts as a snubber between the mounting structure and the bracket to prevent direct contact therebetween. However, in such an arrangement, the provision of the snubber requires further manufacturing steps, which is undesirable. -At its most general, the present invention proposes that a deformable, preferably resilient, flap, which is to form the snubber referred to above, is formed integrally with at least one deformable preferably resilient wall of the hydraulically damped mounting device, the flap being moveable between a stowage position in which it is secured to the first anchor part, and an operative position in which it overlj.es a part of the surface of the mounting structure, e.g. that part of the surface which, in use, will be immediately adjacent to a bracket to which the first anchor part will be attached.

With such an arrangement, the creation of the flap is in the same manufacturing step as the at least one deformable wall and, when the flap is in the stowage position, the mounting device can be attached to the mounting structure without the flap interfering with the correct positioning of the second anchor part in the mounting structure. The flap can then be deformed to the operative position, before a bracket is fitted to the first mounting part.

In this way, a snubber can be formed without requiring an additional manufacturing step, which does not interfere with the correct positioning of the components of the mounting device, but which can be moved to a position in which it can perform its snubbing action without difficulty.

Thus, the present invention may provide a method of making a mounting device, comprising: forming at least one deformable wall on a first anchor part of the mounting device connecting the at least one deformable wall to a second anchor part; and mounting the second anchor part in a apezture, such as a bore, in a mounting structure; wherein, at least one deformable flap is formed integrally with the at least one deformable wall, the at least one deformable flap being secured to the first anchor part in a stowage position during the mounting of the second anchor part in the mounting structure, being subsequently released from the first anchor part, and being deformed to an operative position in which the deformable flap overlies a part of a surface of the mounting structure adjacent the aperture in that mounting structure.

The present invention is particularly applicable to hydraulically damped mounting devices of the "cup and boss" type and to hydraulically damped mounting device of the "bush-type", as discussed above. However, the present invention is also applicable to mounting devices in which there is no hydraulic fluid and it is the deformable wall (usually of resilient material) that controls the vibrations between the anchor parts.

Preferably, the or each flap is resilient, and preferably has an integrally formed strap which fits around the first anchor part when the flap is in its stowage position, and holds the flap in that stowage position.

Once the second anchor part has been mounted in the mounting structure, the strap can be released from the first anchor part, and the flap moved to its operative position. When the flap or flaps have been moved to the operative position, the strap or straps may be hooked onto pins e.g. on the mounting structure, to hold the strap or straps clear of any position where they could interfere with the operation of the mounting device.

In practice, the flap or flaps forming the or each snubber shoulLd have a width less than the width of the bore in the mounting structure, to ensure that it does not interfere with the mounting of the second anchor point in that bore.

An embodiment of the present invention will now be described in detail, by way of example, with reference to the accompanying drawings, in which: Figs la and lb are perspective views showing a hydraulically damped mounting device incorporating the present invention; Figs 2a and 2b show an early stage of the manufacturing sequence of the hydraulically damped mounting device of Figs Ta and lb. at the time of forming a resilient wall; Figs 3a and 3b show a subsequent stage of the manufacturing sequence, in which a flap of the hydraulically damped mounting device is in a secured position; Figs 4a and 4b show a subsequent step of the manufacturing sequence of the hydraulically damped mounting device of Figs la and lb, in which the second anchor part is connected to the structure shown in Figs Ba and 3b; Figs Sa to Sd show a subsequent stage in the manufacturing sequence of the hydraulically damped mounting device of Figs la and lb in which the structure shown in Figs 4a and 4b is fitted into a housing; Figs La to 6d show a subsequent stage in the manufacturing sequence of the mounting device of Figs la and lb, in which the flap is in its operative position; and Figs. 7a and lb show the internal structure of the hydraulically damped mounting device of this embodiment.

Referring first to Figs la and lb, a hydraulically damped mounting device 10 is mounted on a first part 12 of machinery, e.g. the chassis of a vehicle, and a bracket 14 is connected to a first anchor part 16 of the mounting device 10. The bracket 14 may be connected to e.g. the engine (not shown) of the vehicle. When the engine vibrates relative to the chassis, the bracket 14 vibrates relative to the part 12. The bracket 14 is secured a first anchor part 16, which is connected to a second anchor part 18 mounted in a housing 20 forming a mounting structure on the part 12, and the first and second anchor parts 16, 18 are connected by resilient walls which define interconnected chambers for hydraulic fluid. The first anchor part 16 is generally in the shape of an elongate rod, and the second anchor part 18 is generally in the form of a hollow sleeve.

When the bracket 14 vibrates relative to the part 12, the first anchor part 16 is caused to vibrate relative to the second anchor part 18, and that vibration is damped by movement of the hydraulic fluid between the chambers.

The structure of the resilient walls interconnecting the first and second anchor part 16, 18 are not shown in detail in Figs la and ib, and will be discussed in more detail later. However, the present invention is not limited to that structure, and the mounting device structure used in the present invention may be of the "cup and boss" type as well as of the "bush" type of hydraulically damped mounting device, or may be a mounting device in which there is no hydraulic fluid.

Fig lb shows that there is a snubber in the form of a flap 22 covering a part of an end wall of the housing 20, which will lie between that housing and one arm 24 of the bracket 14. There is another such snubber in the form of a further flap 26 (less visible in Fig lb) between the housing 20 and the other arm 28 of the bracket 14. The flaps 22, 26 provide snubbing progression in both axial directions. The arms 24, 28 are secured, at their ends, to the first anchor part 16 e.g. via bolts 30, one of which bolts is visible in Fig la.

The method of manufacture of the hydraulically damped mounting device of Figs la and lb will now be described in more detail.

An early stage in the manufacture of hydraulically damped mounting device is the moulding of rubber material onto one of the anchor parts of the mounting device, which rubber material will form the deformable walls (whether resilient or bellows) of the mount. Thus, in such a step to form the mounting device of Figs la and lb, rubber material 32 shown in Fig 2a is moulded onto the first anchor part 16 with that material 32 being formed into a complex shape which, in due course, will form the internal walls of the hydraulically damped mounting device, and define the chambers for hydraulic fluid. As previously mentioned, the particular arrangement of chambers and passageways of the mounting device of Figs la and lb, and hence of the rubber material 32, will not be discussed in detail now.

However, in addition to the formation of the resilient walls, etc, Fig 2 shows that the flaps 22, 24 are moulded together with the rubber material 32 and integral therewith. The flaps 22, 26 are thus formed in the same manufacturing step as the rubber material 32, thereby simplifying their production. Each flap 22, 26 has an integrated strap 34 associated therewith.

Fig 2b shows a sectional view through the structure shown in Fig 2a. It can thus be seen that, in this stage of the manufacture of the mounting device, the flaps 22, 26 project generally perpendicular to the axis of elongation of the first anchor part 16, when they are rnoulded with the rubber material 32.

The next stage in the manufacturing sequence is illustrated in Figs 3a and 3b. The straps 34 are fitted over the ends of the first anchor part 16 to bring the flaps 22, 26 close to that anchor part 16. As can be seen in Fig 3b, the flaps 22, 26 then extend generally axially from the rubber material 32. It may be noted that, since the straps 34 are formed integrally with the flaps 22, 26, they are of rubber material and hence their resilience makes it easy to deform them over the anchor part 16.

When the flaps 22, 26 are in the position shown in Figs 3a and 3b, they are held in place and cannot then interfere with subsequent steps of the manufacturing sequence as will now be described.

Next, as shown in Figs 4a and 4b, a sleeve forming the second anchor part 18 is fitted around the rubber material 32, and the sleeve crimped to secure the rubber material 32 thereto. The first anchor part 16 extends generally parallel to the cylindrical axis of the sleeve formed by the second anchor part 18, although normally displaced therefrom as is evident by the dotted lines in Fig 4b. Such displacement is necessary to allow for loading between the first and second anchor parts 16, 18, when the hydraulically damped mounting device is in use.

Because the flaps 22, 26 are held in the position shown in Fig 3b by the straps 34, the flaps 22, 26 do not interfere with the insertion of the structure shown in Fig 3a into the sleeve forming the second anchor part 18, making this stage in the assembly simple.

Next, as shown in Figs Sa to Sd, the structure shown in Figs 4a and 4b is inserted into a bore in a housing 40 forming a mounting structure. Again, as can be seen from Fig 5c, the fact that the flaps 22, 26 are held close to the first anchor part 16 by the straps 34 means that the insertion of the second anchor part 18 into the bore in the housing 40 is not impeded by those flaps 22, 26. In this embodiment, the sleeve forming the second anchor part 18 has an interference fit in the housing 40, to hold it thereto, but other attachment arrangements are possible.

Finally, the straps 34 are released from the first anchor part 16, by deforming them, and the flaps 22, 26 folded back to conform the position shown in Fig 2a. In this position, as illustrated in Fig 6a and 6b, the flaps 22, 26 overlie parts of the end faces 42, 44 of the housing 40. To maintain the flaps 22, 26 in that position, the straps 34 may then be fitted over pegs 46 projecting from an outer surface of the housing 40. Again, the resilience of the straps 34, due to the fact that they are made of rubber material, means that the flaps 22, 26 are pulled by the tension in the straps 34 onto the end faces 42, 44, and so the flaps 22, 26 cannot then move away from the end faces 42, 44.

It can be noted that the releasing of the straps 34 from the first anchor part 16, and their fitting to the pegs 46 may be carried out before or after the housing 40 is mounted on the part 12 shown in Fig la and lb. Finally, the bracket 14 is fitted over the housing 40, and the arms 24, 26 of that bracket secured to the ends of the first anchor part 16. The positioning of the flaps 22, 26 is chosen so that, as is evident from Fig lb, they lie between the end faces 42, 44 of the housing and the arms 24, 28 of the bracket 14. Thus, if the bracket 14 moves axially along the longitudinal axis of the bore in the housing 40, relative to the part 12, it will not impact with one of the end faces 42, 44 of the housing, but instead one of the arms 24, 28 will bear against the flap 22 or the flap 26. Since each flap is made of resilient material, this will prevent damage to the end faces 42, 44 or the arms 24, 28, and also will tend to apply a restoring force to the bracket 14. The flaps 22, 26 thus act as snubber pads between the arms 24, 28 of the bracket 14 and the end faces 42, 44 of the housing 40.

In this way, the hydraulically damped mounting device may be provided with integrated axial snubbing on each end of the mount, at the correct place to provide protection and also to apply a resilient load to the adjacent parts of the mounting device when these come close together. With the structure described above, the pads (flaps) forming the snubbing structure do not interfere with the manufacturing process, because the flaps which form those pads are held clear of other parts, other than the first to anchor part which they are strapped, until an appropriate stage in the manufacturing process. The snubbing structure is thus stowed during manufacture of the hydraulically changed mounting device such that its radial extent in that stowed position is small enough to facilitate the subsequent manufacturing processes. The use of straps then enables the snubbing structure to be released, and secured to the housing structure, to maintain the correct positioning of the snubber formed by the flaps 22, 26 during transit and vehicle assembly, when the hydraulically damped mounting device is used e.g. in the manufacture of a vehicle.

Figs. 7a and 7b then show the internal structure of the hydraulically damped mounting device. As is evident from Fig. 7a, the first and second anchor parts 16 and 18 are interconnected by resilient material 50. A first chamber 52 is defined inside the hollow interior of the second anchor part 18, bounded by a member 54 abutting against part of the rubber material 50. The chamber 52 is connected via a passageway 56 to a second chamber 58, again which is inside the second anchor part 18 and is bounded by a flexible wall 60 of the rubber material 50.

When the first anchor part 16 moves downwardly in Fig. 7a, relative to the second anchor part 18, the resilient material 50 forces the member 54 downwards, reducing the volume of the chamber 52. Hydraulic fluid then passes from that chamber 52 through the passageway 56 to the chamber 58. That hydraulic fluid movement is compensated for by deformation of the flexible wall 60. Thus, in such an arrangement, the chamber 52 acts as a working chamber and the chamber 58 is a compensation chamber. The movement of the fluid between the chambers 52, 58 through the passageway 56 damps the vibrations. As the first anchor part 16 moves upwardly relative to the second anchor part 18, the fluid flow is in the opposite direction, again with a damping action.

Note that, in order to provide internal walls of the passageway 56, there may be rigid walls 62, 64 is in the second anchor part 18 moulded within the rubber material 50. And there are also additional voids 66 within the material 50.

The hydraulically damp mounting device shown in Figs. 7a and 7b is a relatively simple one, and the present invention is also applicable to the more complicated mounting devices described earlier, such as EP-A-0172700 or GB-A-2322427. Moreover, the present invention is applicable to mounting devices which do not use hydraulic fluid.

Claims

CLAIMS1. A method of making a mounting device, comprising; forming at least one deformable wall on a first anchor part of the mounting device; connecting the at least one deformable wall to a second anchor part; and -mounting the second anchor part in a aperture, such as a bore, in a mounting structure; wherein, at least one deformable flap is formed integrally with the at least one deformable wall, the at least one deformable flap being secured to the first anchor part in a stowage position during the mounting of the second anchor part in the mounting structure, being subsequently released from the first anchor part, and being deformed to an operation position in which the deformable flap overlies a part of a surface of the mounting structure adjacent to the aperture in that mounting structure.
2. A method according to claim 1, wherein the or each deformable flap is resilient.
3. A method according to claim 2, wherein the or each deformable flap has an integrally formed strap which fits around the first anchor part when the deformnable flap is in its stowage position, and holds the deformable flap in that stowage position.
4. A method according to claim 3, wherein, once the second anchor part is mounted in the mounting structure, the strap is released from the first anchor part and the deformable flap is moved to its operative position such that the deformable flap overlies a part of the surface of the mounting structure adjacent to the aperture in that mounting structure.
5. A method according to any of the preceding claims, wherein the or each deformable flap has a width less than the width of the aperture in the mounting structure.
6. A method according to any one of the preceding claims, wherein the mounting device is a hydraulically damped mounting device, and the step of connecting the at least one deformable wall to the second anchor part forms a working chamber for hydraulic fluid, the working chamber being at least partially bounded by the at least one deformable wall and being connected by a passageway to a compensation chamber for hydraulic fluid.
7. A method according to any one of the preceding claims, wherein the deformable wall is resilient.