Patent Description:
Conventional mounts exist for supporting and providing vibration isolation of vibration sources. One well-known application of these mounts is for supporting components of automotive vehicles. These mounts typically operate to provide engine vibration isolation while also to control the motion of the engine and connected powertrain components with respect to the vehicle frame or body structure. In many applications of engine and powertrain mounts, it is desirable to vary damping characteristics of the mount to provide selective isolation of vibrations at certain frequencies.

One such hydraulic mount apparatus is disclosed in <CIT>. The hydraulic mount apparatus includes a housing having an upper portion and a lower portion disposed on a center axis and defining a housing chamber. A partition member is disposed in the housing chamber dividing the housing chamber into a pumping chamber and a receiving chamber. The pumping chamber extends between the upper portion and the partition member. The receiving chamber extends between the lower portion and the partition member. A decoupler is attached to the partition member separating the pumping chamber and the receiving chamber. A moving member of elastomeric material disposed in the pumping chamber attached to the decoupler.

Typically, metallic inserts are embedded in the moving member to allow a user to change the stiffness of the moving member. However, the inclusion of the metallic inserts in the moving members increases the manufacturing costs of the hydraulic mount apparatus. In addition, the elastomeric material and the metallic inserts can chemically react with the fluid in the hydraulic mount apparatus and, thus, reducing the life of the hydraulic mount apparatus.

Document <CIT> discloses a method for attenuating vibration, an active hydraulic damping support, and a vehicle comprising such a support. The method of damping engine vibrations in a motor vehicle involves using a vibration damping mounting with a rigid diaphragm having an opening closed by a flap which is movable freely at right angles to the opening. The flap has one face exposed to the liquid in a working chamber and a second face isolated from the chamber. The flap movement is limited by stops to allow variations in volume of the working chamber.

Document <CIT> discloses a valve for a hydroelastic support. The suspension unit has a body formed by an elastomer block connecting upper and lower supports, and liquid-filled working and expansion chambers separated by a valve with its outer edge set in a holder. The valve has a centre portion or disc made from a rigid material, and an outer ring of a supple material, produced by bi-injection or made separate and joined together by adhesion or mechanical fixing. The materials used for the valve components are e.g. rigid or semi-rigid polymers such as thermoplastic or thermo-setting elastomers.

The present invention provides a hydraulic damper that eliminates the need for metallic inserts in a moving member of a hydraulic mount apparatus. The present invention also prevents the moving member from extruding into the compression plate under positive pressure and into the cap under vacuum. The present invention further reduces the amount elastomeric material, e.g. rubber, in the moving member thereby improving the life of the hydraulic mount apparatus.

It is one aspect of the present invention to provide a hydraulic mount apparatus including a housing having an upper portion and a lower portion disposed on a center axis and defining a housing chamber. A partition member is disposed in the housing chamber dividing the housing chamber into a pumping chamber and a receiving chamber. The pumping chamber extends between the upper portion and the partition member. The receiving chamber extends between the lower portion and the partition member. A decoupler is attached to the partition member separating the pumping chamber and the receiving chamber. A moving member is disposed in the pumping chamber attached to the decoupler. The moving member is a non-elastomeric polymer sheet secured to the decoupler for providing the additional damping force. The hydraulic mount apparatus further includes a cap disposed in said pumping chamber spaced from said decoupler to secure said moving member between said cap and said decoupler. The cap includes a lower plate disposed axially spaced from said moving member and a protrusion extending annularly outwardly from said lower plate toward said decoupler to engage said moving member and secure said moving member to said decoupler. The cap includes a rib extending annularly outwardly from said lower plate and parallel to said center axis in a direction opposite of said protrusion with said rib having an inner surface facing said center axis and an outer surface opposite of said inner surface defining a pocket disposed in fluid communication with said pumping chamber between said inner surface and said lower plate. The moving member is a die-cut polymer sheet having an outer periphery extending about said center axis.

It is another aspect of the present invention to provide a decoupler for a hydraulic mount apparatus. The decoupler includes a support member disposed on a center axis and extending between a support member upper end and a support member lower end. A moving member is disposed on the center axis, extending radially outwardly from the center axis to the support member upper end, and is attached to the support member upper end. The moving member is a non-elastomeric polymer sheet secured to the decoupler for providing the additional damping force. The decoupler further includes a cap disposed in said pumping chamber to secure said moving member between said cap and said support member. The cap includes a lower plate disposed axially spaced from said moving member and a protrusion extending annularly outwardly from said lower plate toward said support member to engage said moving member and secure said moving member to said support member. The cap includes a rib extending annularly outwardly from said lower plate and parallel to said center axis in a direction opposite of said protrusion with said rib having an inner surface facing said center axis and an outer surface opposite of said inner surface defining a pocket disposed in fluid communication with said pumping chamber between said inner surface and said lower plate.

Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a hydraulic mount apparatus <NUM> constructed in accordance with one embodiment of the present invention is generally shown in <FIG>. Typically, the hydraulic mount apparatus <NUM> is used for supporting a component of a vehicle, e.g. an engine, disposed on a frame of the vehicle. It should be appreciated that the hydraulic mount apparatus <NUM> can be used for supporting various other vibration sources.

As generally shown in <FIG>, the hydraulic mount apparatus <NUM> includes a housing <NUM> having a lower portion <NUM> and an upper portion <NUM>. The lower portion <NUM> and the upper portion <NUM> are disposed on a center axis A and axially spaced from one another. A wall <NUM>, having a generally tubular shape, is disposed on the center axis A and extends between the lower portion <NUM> and the upper portion <NUM> to connect the lower portion <NUM> with the upper portion <NUM> and defining a housing chamber <NUM>, <NUM>, <NUM> extending between the lower portion <NUM>, the upper portion <NUM>, and the wall <NUM>.

The lower portion <NUM>, having a generally bowl shape, extends annularly about the center axis A between a lower portion closed end <NUM> and a lower portion opened end <NUM>. A lower portion lip <NUM> extends radially outwardly from the lower portion opened end <NUM>, perpendicular to the center axis A, to engage the wall <NUM>. The lower portion <NUM> includes a collar <NUM>, having a cylindrical shape, disposed on the center axis A. The collar <NUM> extends outwardly from the lower portion closed end <NUM> and annularly about the center axis A to a distal end <NUM>. The collar <NUM> defines a lower portion bore <NUM>, having a generally cylindrical shape, extending along the center axis A between the lower portion <NUM> and the distal end <NUM> for attaching the housing <NUM> to a vehicle.

The upper portion <NUM>, having a generally tubular shape, is disposed on the center axis A and axially spaced from the lower portion <NUM>. The upper portion <NUM> extends annularly about the center axis A between a first opened end <NUM> and a second opened end <NUM>. The upper portion <NUM> defines an upper portion bore <NUM>, having a generally cylindrical shape, extending along the center axis A between the first opened end <NUM> and the second opened end <NUM>. The upper portion <NUM> includes an upper portion lip <NUM>, disposed at the second opened end <NUM>, and extends radially outwardly from the first opened end <NUM> in a perpendicular relationship with the center axis A to engage the wall <NUM>. It should be appreciated that the upper portion <NUM> and the lower portion <NUM> can have other shapes (e.g. square shaped or hexagonal shaped cross sections).

A flexible body <NUM>, made from elastomeric material, is disposed in the upper portion bore <NUM>. The flexible body <NUM> extends annularly about and axially along the center axis A from a flexible body lower end <NUM> to a flexible body upper end <NUM>. The flexible body lower end <NUM> is adjacent to the second opened end <NUM> of the upper portion <NUM>. The flexible body upper end <NUM> is adjacent to the first opened end <NUM> of the upper portion <NUM> for deforming elastically relative to the lower portion <NUM> in response to an excitation movement of a vehicle. In other words, the flexible body <NUM> is attached to the upper portion <NUM> and deforms in response to an excitation movement of the vehicle, e.g. a vibrational movement. The flexible body <NUM> defines a flexible chamber <NUM> disposed adjacent to the flexible body upper end <NUM> extending axially into the flexible body <NUM> from the flexible body upper end <NUM>. The flexible body <NUM> further defines a pair of insert grooves <NUM> disposed adjacent to and spaced from the flexible chamber <NUM> and extending between the flexible body lower end <NUM> and the flexible body upper end <NUM>.

A bushing <NUM>, having a generally cylindrical shape, is disposed in the flexible chamber <NUM> for receiving a fastener to secure the flexible body <NUM> to the vehicle. A pair of outer inserts <NUM>, made from a metallic material, is disposed in the insert grooves <NUM> for providing rigidity to the flexible body <NUM>. The flexible body <NUM> includes a flexible body flange <NUM> extending radially outwardly from the flexible body lower end <NUM>, in a parallel relationship with the upper portion lip <NUM>, for engagement with the upper portion lip <NUM> to secure the flexible body <NUM> to the upper portion <NUM>.

A partition member <NUM> is disposed in the housing chamber <NUM>, <NUM>, <NUM>, between the upper portion <NUM> and the lower portion <NUM>, and extends annularly about the center axis A. The partitioning member <NUM> divides the housing chamber <NUM>, <NUM>, <NUM> into a pumping chamber <NUM> and a receiving chamber <NUM>, <NUM>. The pumping chamber <NUM> extends between the flexible body <NUM> and the partition member <NUM>. The receiving chamber <NUM>, <NUM> extends between the lower portion <NUM> and the partition member <NUM>. In one embodiment of the present invention, a magnetorheological fluid can be contained in the pumping chamber <NUM> and the receiving chamber <NUM>, <NUM>. The magnetorheological fluid, as known in the art, is responsive to modify its shear properties. More specifically, in responsive to a magnetic field applied to the magnetorheological fluid, the magnetorheological fluid has the ability to modify its shear property from a free-flowing or a viscous liquid to a semi-solid with controllable yield strength.

As best shown in <FIG> and <FIG>, a decoupler <NUM> is disposed in the housing chamber <NUM>, <NUM>, <NUM> and attached to the partition member <NUM> to separate the pumping chamber <NUM> and the receiving chamber <NUM>, <NUM> and to provide additional damping force in the pumping chamber <NUM>. The decoupler <NUM> includes a support member <NUM>, made from metal and having a generally tubular shape, attached to the partition member <NUM>. The support member <NUM> extends annularly about and along the center axis A between a support member upper end <NUM> and a support member lower end <NUM>. The support member upper end <NUM> is disposed in the pumping chamber <NUM>. The support member lower end <NUM> is disposed in the receiving chamber <NUM>, <NUM>. A support member upper flange <NUM> extends radially outwardly from the support member upper end <NUM> and annularly about the center axis A to engage the partition member <NUM>. A base <NUM>, having a generally circular shape, is attached to the support member lower end <NUM> defining a recess <NUM>, having a generally cylindrical shape, extending along the center axis A between the base <NUM>, the support member upper end <NUM>, and the support member lower end <NUM>. A support member lower flange <NUM> extends outwardly from the base <NUM>, along the center axis A, and annularly about the center axis A toward the lower portion to engage the distal end <NUM> of the collar <NUM>.

The decoupler <NUM> includes a moving member <NUM>, having a generally circular shape, disposed on the center axis A in the pumping chamber <NUM>. The moving member <NUM> extends radially outwardly from the center axis A to the support member upper end <NUM>. The decoupler <NUM> is attached to the support member upper end <NUM> separating the pumping chamber <NUM> from the receiving chamber <NUM>, <NUM>. A diaphragm <NUM>, made from an elastomeric material, is disposed in the receiving chamber <NUM>, <NUM>. The diaphragm <NUM> extends annularly about the center axis A between the lower portion opened end <NUM> and the distal end <NUM> of the collar <NUM>. The diaphragm <NUM> is sandwiched between the lower portion <NUM> and the partition member <NUM> and the support member lower flange <NUM> and the distal end <NUM> of the collar <NUM> dividing the receiving chamber into a fluid chamber <NUM> and a compensation chamber <NUM>. The fluid chamber <NUM> extends between the diaphragm <NUM> and the partition member <NUM>. The compensation chamber <NUM> extends between the lower portion <NUM> and the diaphragm <NUM>.

The partition member <NUM> includes an upper spacer <NUM>, made of metal and having a generally circular shape, disposed in the pumping chamber <NUM>, axially adjacent to and below the upper portion <NUM>, and in engagement with the flexible body flange <NUM> to sandwich the flexible body flange <NUM> between the upper portion <NUM> and the upper spacer <NUM>. The upper spacer <NUM> includes at least one projection <NUM> extending outwardly from the upper spacer <NUM> to engage the flexible body flange <NUM> for securing the flexible body flange <NUM> between the upper portion <NUM> and the upper spacer <NUM>. The upper spacer <NUM> defines at least one upper spacer groove <NUM>, disposed opposite of the at least one projection <NUM> and axially spaced from the at least one projection <NUM>, extending annularly about the center axis A along the upper spacer <NUM>. A seal <NUM>, made from an elastomeric material, is disposed in the upper spacer groove <NUM> and extends annularly about the center axis A.

The partition member <NUM> includes an electromagnetic support ring <NUM>, having a generally circular shape disposed in said fluid chamber <NUM> between the upper spacer <NUM> and the lower portion <NUM>. The electromagnetic support ring <NUM> extends annularly about the center axis A to sandwich the diaphragm <NUM> between the electromagnetic support ring <NUM> and the lower portion <NUM>. The electromagnetic support ring <NUM> also sandwiches the seal <NUM> between the electromagnetic support ring <NUM> and the upper spacer <NUM>. The electromagnetic support ring <NUM> defines a concavity <NUM>, at least one channel <NUM>, and an electromagnetic groove <NUM>. The concavity <NUM>, having a generally cylindrical shape, extends along the center axis A to receive the decoupler <NUM>. The at least one channel <NUM>, radially spaced from the concavity <NUM> and the decoupler <NUM>, extends through the electromagnetic support ring <NUM> parallel to the center axis A to allow fluid communication between the pumping chamber <NUM> and the fluid chamber <NUM>. The electromagnetic groove <NUM>, disposed adjacent to the wall <NUM> and radially spaced from the at least one channel <NUM>, extends annularly about the center axis A. An electromagnetic field generator <NUM> is disposed in the electromagnetic groove <NUM>. The electromagnetic field generator <NUM> includes a bobbin <NUM>, having a generally spool shape, disposed in the electromagnetic groove <NUM> and extending annularly about the center axis A. At least one coil <NUM> is annularly wrapped around the bobbin <NUM> and is electrically connected to a power source <NUM> for selectively generating a magnetic flux.

As best shown in <FIG>, the moving member <NUM> is a non-elastomeric polymer sheet secured to the decoupler <NUM> for providing the additional damping force. The moving member <NUM>, having a generally circular shape, is a die cut polymer sheet and having an outer periphery <NUM> extending about the center axis A. With the moving member <NUM> being a non-elastomeric polymer, it also minimizes the chemical reaction between the moving member <NUM> and the magnetorheological fluid thereby prolonging the operation life of the decoupler <NUM> and the hydraulic mount apparatus <NUM>.

More specifically, studies have shown that ethoxylated amines, propylene glycol and other additives contained in the magnetorheological fluid tend to reacts with the elastomeric material of the hydraulic mount apparatus <NUM>. This chemical reaction generates gases in the hydraulic mount apparatus <NUM> that causes pressure buildup <NUM> thereby inhibiting the full functional performance of the hydraulic mount apparatus <NUM>. In addition, the reaction also forms dimers and trimers in the magnetorheological fluid composition disrupting the thixotropic network formed in the magnetorheological fluid composition and causing the magnetic responsive particles to settle out of the magnetorheological fluid composition reducing the life of the magnetorheological fluid composition. With the moving member <NUM> being a non-elastomeric polymer, the present invention minimizes the chemical reaction between the moving member <NUM> and the magnetorheological fluid to prevent the magnetic responsive particles from settling out of the magnetorheological fluid and allow the decoupler <NUM> and the hydraulic mount apparatus <NUM> to operate over a longer period of time.

A cap <NUM>, having a generally circular shape, is disposed in the pumping chamber <NUM>, spaced from the decoupler <NUM>, to secure the moving member <NUM> between the cap <NUM> and the decoupler <NUM>. The cap <NUM> includes a lower plate <NUM>, having a generally circular shape, disposed axially spaced from the moving member <NUM>. A protrusion <NUM> extends outwardly from the lower plate <NUM> toward the decoupler <NUM> to engage the moving member <NUM> and secure the moving member <NUM> to the decoupler <NUM>. It should be appreciated that the protrusion <NUM> can extend annularly about the center axis A to secure the moving member <NUM> to the decoupler <NUM>. The lower plate <NUM> defines at least one orifice <NUM> extending through the cap <NUM> for allowing the magnetorheological fluid to flow through the cap <NUM>. It should be appreciated that the at least one orifice <NUM> can include a plurality of orifices <NUM>, radially and circumferentially spaced from one another, to allow the magnetorheological fluid to flow through the cap <NUM>.

The cap <NUM> includes a rib <NUM> extending annularly outwardly from the lower plate <NUM> parallel to the center axis A in a direction opposite of the protrusion <NUM>. The rib <NUM> has an inner surface <NUM> and an outer surface <NUM>. The inner surface <NUM> of the rib <NUM> is facing the center axis A. The outer surface <NUM> of the rib <NUM> is disposed on an opposite side from the inner surface <NUM> and facing the wall <NUM>. The cap <NUM> defines a pocket <NUM> disposed in fluid communication with the pumping chamber <NUM>. The pocket <NUM> extends between the inner surface <NUM> of the rib <NUM> and the lower plate <NUM>. The outer surface <NUM> is chamfered near the outer periphery <NUM> of the moving member <NUM> defining a conduit <NUM> extending annularly about the center axis A. An O-ring <NUM>, made from elastomeric material, is disposed in the conduit <NUM> and extends annularly about the center axis A in sealing engagement with the outer surface <NUM> and the outer periphery <NUM> of the moving member <NUM>. The decoupler includes a compression plate <NUM> disposed in the recess <NUM> adjacent and spaced from the moving member <NUM> on a side opposite of the cap <NUM> for limiting the movement of the moving member <NUM>. In other words, the only rubber component in the decoupler is the O-ring <NUM>, which provides a sealing function between the cap <NUM> and the moving member <NUM>. In addition, it should be appreciated that the moving member <NUM>, made from the non-elastomeric polymer, has a stiffness greater than rubber, which provides a low cost alternative to using an elastomeric moving member including metal inserts thereby limiting the need of the metallic inserts. Further, combination of the O-ring <NUM> and the cap <NUM> allows the moving member <NUM> to be properly secured to the decoupler <NUM> and resist the extrusion of the moving member <NUM> into the compression plate <NUM> under a positive pressure and into the cap <NUM> under vacuum.

<FIG> provides an alternative embodiment of the decoupler <NUM> of the present invention. As illustrated in <FIG>, a strain gauge sensor <NUM> is disposed in the fluid chamber <NUM> and attached to the moving member <NUM> for measuring a load on the moving member <NUM> as a function of the movement of the moving member <NUM>. A lead wire <NUM> is electrically connected to the strain gauge sensor <NUM> and extends through the compression plate <NUM>. The lead wire <NUM> is also electrically connected to a processor for receiving and analyzing a signal received from the strain gauge sensor <NUM>. In other words, the signal generated by the strain gauge sensor <NUM> allows a user to measure the frequency content of the moving member <NUM> of the decoupler <NUM>. The compression plate <NUM> defines a passage <NUM> extending through the compression plate <NUM> for receiving the lead wire <NUM> to allow the lead wire <NUM> to extend through the decoupler <NUM>. It should be appreciated that, instead of a lead wire <NUM>, the strain gauge sensor <NUM> can include a wireless module that can transfer the signals of the stain gauge sensor <NUM> wirelessly to the user.

In operation, as the hydraulic mount apparatus <NUM> receives an excitation movement, e.g. a vibrational movement, the flexible body <NUM> deforms thereby causing a change in the volumes of the pumping chamber <NUM>, the fluid chamber <NUM>, and the compensation chamber <NUM>. As a result, the moving member <NUM> flexes in the pumping chamber <NUM> in response to the volume change. As the moving member <NUM> flexes in the pumping chamber <NUM>, the moving member <NUM> provides an additional damping force in the pump chamber <NUM> in response to the excitation movement. As the moving member <NUM> is flexing in the pumping chamber <NUM>, the strain gauge sensor <NUM> records and monitors the moving member <NUM> and measure the load of the moving member <NUM> as a function of the movement of the moving member <NUM>. The signal generated by the strain gauge sensor <NUM> is communicated via the lead wire <NUM> to a user, which allows the user to measure the frequency content of the moving member <NUM> of the decoupler <NUM>.

Claim 1:
A hydraulic mount apparatus (<NUM>) comprising:
a housing (<NUM>) having an upper portion (<NUM>) and a lower portion (<NUM>) disposed on a center axis and defining a housing chamber (<NUM>, <NUM>, <NUM>);
a partition member (<NUM>) disposed in said housing chamber (<NUM>, <NUM>, <NUM>) dividing said housing chamber (<NUM>, <NUM>, <NUM>) into a pumping chamber (<NUM>) and a receiving chamber (<NUM>, <NUM>) with said pumping chamber (<NUM>) being between said upper portion (<NUM>) and said partition member (<NUM>) and said receiving chamber (<NUM>, <NUM>) being between said lower portion (<NUM>) and said partition member (<NUM>);
a decoupler (<NUM>) attached to said partition member (<NUM>) separating said pumping chamber (<NUM>) and said receiving chamber (<NUM>, <NUM>); and
a moving member (<NUM>) disposed in said pumping chamber (<NUM>) attached to said decoupler (<NUM>);
wherein said moving member (<NUM>) is a non-elastomeric polymer sheet secured to said decoupler (<NUM>) for providing the additional damping force,
wherein said hydraulic mount apparatus (<NUM>) further includes a cap (<NUM>) disposed in said pumping chamber (<NUM>) spaced from said decoupler (<NUM>) to secure said moving member (<NUM>) between said cap (<NUM>) and said decoupler (<NUM>),
wherein said cap (<NUM>) includes a lower plate (<NUM>) disposed axially spaced from said moving member (<NUM>) and a protrusion (<NUM>) extending annularly outwardly from said lower plate (<NUM>) toward said decoupler (<NUM>) to engage said moving member (<NUM>) and secure said moving member (<NUM>) to said decoupler (<NUM>),
characterized in that said cap (<NUM>) includes a rib (<NUM>) extending annularly outwardly from said lower plate (<NUM>) and parallel to said center axis in a direction opposite of said protrusion (<NUM>) with said rib (<NUM>) having an inner surface (<NUM>) facing said center axis and an outer surface (<NUM>) opposite of said inner surface (<NUM>) defining a pocket (<NUM>) disposed in fluid communication with said pumping chamber (<NUM>) between said inner surface (<NUM>) and said lower plate (<NUM>), wherein said moving member (<NUM>) is a die-cut polymer sheet having an outer periphery extending about said center axis.