Hydraulic mount having unidirectional damping membrane

The present disclosure relates to a hydraulic mount having a unidirectional damping membrane. A hole is formed in a membrane and a one-way closure having upper and lower portions, which are different from each other, is inserted into the hole to control a flow of a fluid. The one-way closure means includes: a body which intermittently closes a lower side of the hole formed at a center of the membrane; a column portion which is vertically formed at a center of the body; and a moving closure which is formed at an upper portion of the column portion and closes an upper side of the hole.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2017-0133732, filed on Oct. 16, 2017, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

The present disclosure relates to a hydraulic mount having a unidirectional damping membrane.

2. Description of the Related Art

In general, an engine of a vehicle always and structurally vibrates due to a periodic change in center position of the engine caused by upward and downward movements of a piston and a connecting rod, and a periodic change in inertial force applied to reciprocating parts in an axial direction of a cylinder, inertial force occurring when the connecting rod is rattled leftward and rightward about a crank shaft, and rotational force applied to the crank shaft.

The causes of the vibration do not act separately but always act in a complex manner, such that the engine vibrates upward and downward and leftward and rightward. In particular, an engine having a small number of cylinders more greatly vibrates than an engine having a large number of cylinders, and the engine more greatly vibrates when the engine operates at a low speed than when the engine operates at a high speed.

As described above, the vibration inevitably occurs when the engine operates, and the vibration generated by the engine is transferred to a vehicle interior through a vehicle body on which the engine is installed. The vibration transferred to the vehicle interior causes discomfort to an occupant and degrades a pleasant driving environment, and an occupant's body may be seriously injured if the vibration is intense.

The disclosure of this section is to provide background of the invention. Applicant notes that this section may contain information available before this application. However, by providing this section, Applicant does not admit that any information contained in this section constitutes prior art.

SUMMARY

An engine mount having a vibration proof function is provided between the engine and the vehicle body in order to prevent the vibration from being transferred to the vehicle body. There are a rubber engine mount manufactured by using rubber, a hydraulic engine mount in which a liquid having viscosity is encapsulated to improve vibration damping force, and an air damper mount which is filled with air instead of a fluid to ensure a damping effect.

The rubber engine mount is inexpensive compared to a fluid engine mount but disadvantageous in damping characteristics. The fluid engine mount has an advantage because the fluid engine mount insulates vibration and noise by means of a damping effect in respect to a fluid mass, but the fluid engine mount is disadvantageous because the fluid engine mount is expensive.

The air damper mount is disadvantageous in terms of costs compared to the rubber engine mount but advantageous in terms of costs compared to the fluid engine mount, and the air damper mount is disadvantageous in terms of performance compared to the fluid engine mount but advantageous in terms of performance compared to the rubber engine mount. Assuming that an operating chamber of the air damper mount has a size and a shape similar to those of the fluid damper mount, the air damper mount has a lower performance than the fluid damper mount because air, which has lower properties such as viscosity than oil, is used as a working fluid.

To solve the problems, the inventions in the related art, which are disclosed in WO 2004/031608 and Japanese Patent Application Laid-Open Nos. 2002-349631 and 2001-214953, adopt a method of increasing friction damping by increasing the amount of fluid flowing between the operating chambers in respect to the same variation in vibration, and to this end, a diameter of the mount is increased.

However, since the working fluid is air, which is a compressive fluid, in the air damping mount in the related art, a damping performance is exhibited by friction damping as the air passes through a die channel in the case of vibration with a low frequency, but the air does not pass through the die channel in the case of vibration with a predetermined frequency or higher. For this reason, the damping performance deteriorates, and a situation similar to a situation in which a working chamber is sealed is made, such that pressure in the working chamber is increased, and stiffness of the mount is increased.

Therefore, as a solution for solving the problems, “Air Damping Mount with Variable Effective Area” disclosed in Korean Patent No. 10-1262412 has been developed.

As illustrated inFIG. 1, the damping mount includes an engine mounting unit10which is fixed to an engine, a main rubber11which is coupled to a lower side of the engine mounting unit10and attenuates vibration being transferred from the engine, an upper chamber13which is installed at a lower side of the main rubber11so as to be filled with air, and has a die channel12that is penetratively formed at one side of a bottom surface to allow air to flow inward and outward, a working chamber14which is installed at a lower side of the upper chamber13so as to be filled with air, and has an outside air connecting hole14athat is penetratively formed at one side to communicate with outside air, a rigid chamber15which is installed at a lower side of the working chamber14so as to be filled with air, and has an installation hole15athat is penetratively formed at one side of an upper surface to communicate with the working chamber14, a plurality of pressure transfer tubes17which allows the rigid chamber15and the upper chamber13to communicate with each other so that the air with which the rigid chamber15and the upper chamber13are filled may flow, and an effective area control rod16which is installed in the rigid chamber15while penetrating the installation hole15aso as to be movable upward and downward, and changes an effective area of the die channel, which is an actual area through which the air flows through the die channel12, while moving upward and downward in accordance with pressure in the rigid chamber15that varies in accordance with pressure in the upper chamber13.

The air damping mount with a variable effective area is lowered in proportion to an increase in pressure when internal pressure of the rigid chamber150is equal to or higher than stiffness of a leaf spring as pressure in the upper chamber13increases, and the air damping mount returns to the original position when the internal pressure of the rigid chamber15is equal to or lower than the stiffness of the leaf spring as the pressure in the upper chamber13decreases. A diaphragm portion15bmoves the effective area control rod16while moving upward and downward in accordance with the pressure in the rigid chamber15that varies in accordance with a change in pressure in the upper chamber13, thereby changing the effective area of the die channel12.

However, the diaphragm portion15breceives pressure of the fluid flowing from the upper chamber13or the rigid chamber15since the control rod16is integrated with the diaphragm portion15b, and in this case, an operating unit16chaving a conical shape tends not to properly block the installation hole15adue to unbalance of liquid pressure or the like.

DOCUMENTS OF RELATED ART

The present disclosure relates to a hydraulic mount having a unidirectional damping membrane, in which a hole is formed in a membrane and a one-way closure having upper and lower portions, which are different from each other, is inserted into the hole to control a flow of a fluid.

The present disclosure has been made in an effort to provide a hydraulic mount having a unidirectional damping membrane, in which a hole is formed in a membrane and a one-way closure made of a soft material such as an insulator or a silicone material is installed in the hole, such that low dynamic properties may be made as the one-way closure moves into the hole formed in the membrane when a fluid flows into a lower liquid chamber, and a high damping value may be obtained as the hole is closed by the one-way closure such that the fluid flows only into an orifice when the fluid flows into an upper liquid chamber.

An embodiment of the present invention provides a hydraulic mount which includes: an engine mount10which has a center bolt that is inserted into a housing20and fastened to an engine; a main rubber11which is provided at an outer circumferential surface of the engine mount; and a membrane30which vibrates in response to elastic behavior of the main rubber and divides an interior into an upper liquid chamber and a lower liquid chamber, thereby providing a driver seated in a vehicle with comfortable ride quality by absorbing an impact applied to the vehicle and thus preventing damage to a vehicle body or maintaining coupled states of components. A hole31is formed at a central portion of the membrane30so that a fluid flows into the upper liquid chamber and the lower liquid chamber by outside pressure, and a one-way closure means100is installed in the hole31. The one-way closure means100includes: a body110which intermittently closes a lower side of the hole31formed at the center of the membrane30; a column portion120which is vertically formed at a center of the body; and a moving closure130which is formed at an upper portion of the column portion and closes an upper side of the hole31.

The hydraulic mount having a unidirectional damping membrane according to embodiments of the present invention may have the following effects.

First, since the one-way closure means is installed in the membrane, such that low dynamic properties may be made as the one-way closure means moves into the hole formed in the membrane when the fluid flows into the lower liquid chamber, and a high damping value may be obtained as the hole is closed by the one-way closure such that the fluid flows only into the orifice when the fluid flows into the upper liquid chamber.

Second, the one-way closure means is installed at the center of the membrane, a longitudinal protrusion is formed at the upper portion of the one-way closure means, and a lateral protrusion is formed at the lower portion of the one-way closure means, such that a flow of the fluid may vary (in a low frequency band, an intermediate frequency band, and a high frequency band).

Third, a metal material is inserted into any one or both of the body and the column portion that constitute the one-way closure means, and as a result, the one-way closure means may serve as a dynamic damper.

Fourth, the one-way closure means into which the metal material is inserted shifts a resonance region of the mount to a low frequency band, and as a result, it is easy to separate the resonance region from a vehicle vibratory frequency.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains may easily carry out the present invention. However, the present invention may be implemented in various different ways, and is not limited to embodiments described herein.

A part irrelevant to the description will be omitted to clearly describe embodiments of the present invention, and the same or similar constituent elements will be designated by the same reference numerals throughout the specification.

Terms or words used in the specification and the claims should not be interpreted as being limited to a general or dictionary meaning and should be interpreted as a meaning and a concept which conform to the technical spirit of the present invention based on a principle that an inventor can appropriately define a concept of a term in order to describe his/her own invention by the best method.

According to an aspect of the present invention, a hydraulic mount for mounting an engine on a vehicle frame is disclosed. The hydraulic mount comprising two liquid chambers—an upper liquid chamber and a lower liquid chamber. An elastic membrane30interposed between the liquid chambers has a through hole31connecting the upper liquid chamber and the lower liquid chamber.

In embodiments, a rigid closure member100inserted into the through hole31, in its closing position (with respect to the through hole31), blocks liquid communication between the upper liquid chamber and the lower liquid chamber when no external vibration is transferred to the hydraulic engine mount. In embodiments, in response to an upward vibration from the bottom of the lower liquid chamber, the rigid closure member100is lifted, from the closing position to an opening position, to allow liquid communication between the upper liquid chamber and the lower liquid chamber such that damping against the upward vibration is provided.

In embodiments, in response to a downward vibration applied from the top of the upper liquid chamber, the closure member100moves down together with a portion of the membrane contacting the closure member100. However the closure member100remains its closing position with respect to the through hole31such that disconnection between the upper liquid chamber and the lower liquid chamber is maintained regardless of downward movement of the closure member100. Accordingly, flow between the two liquid chambers across the membrane through the hole31is restricted to one direction from the lower liquid chamber to the upper liquid chamber such that damping of the hydraulic mount is unidirectional (responsive to an upward vibration from the bottom and not responsive to a downward vibration from the top).

As illustrated inFIG. 2, a hydraulic mount having a unidirectional damping membrane according to embodiments of the present invention is basically identical to the related art in that the hydraulic mount includes an engine mount10which has a center bolt that is inserted into a housing20and fastened to an engine, a main rubber11which is provided at an outer circumferential surface of the engine mount, and a membrane30which vibrates in response to elastic behavior of the main rubber and divides an interior into an upper liquid chamber and a lower liquid chamber.

In some embodiments, a hole31is formed at a central portion of the membrane30so that a fluid flows into the upper liquid chamber and the lower liquid chamber by outside pressure, and a one-way closure means100is installed in the hole31.

In more detail, the one-way closure means100is made of an insulator or a silicone material, and as illustrated inFIG. 3orFIGS. 4A and 4B, a body110is formed to intermittently close a lower side of the hole31formed at the center of the membrane30, and a column portion120is vertically formed at a center of the body110.

A moving closure130for closing an upper side of the hole formed in the membrane30is integrally formed at an upper portion of the column portion120.

In this case, the upper portion of the body110has a conical shape entirely having an inclined surface, and ring-shaped protrusions111protrude at an equal interval about a center of the column portion120. In addition, a lower portion of the moving closure130has an inverted conical shape, and a plurality of longitudinal protrusions131protrudes at an equal interval. The longitudinal protrusion131is a protrusion in the form of a long band and serves to allow the fluid to flow through the hole31formed in the membrane30when the fluid flows from the upper liquid chamber to the lower liquid chamber, that is, the longitudinal protrusion131serves as a dual orifice.

Therefore, as described above, a target frequency dualization is enabled by dynamic characteristics by the dual orifice, and resistance is reduced when the fluid flows, such that dynamic characteristics may be established.

In addition, as the ring-shaped protrusions111close the hole31formed in the membrane30, a flow of the fluid flowing from the upper liquid chamber to the lower liquid chamber is perfectly blocked, and a flow of the fluid is guided only to the orifice, thereby ensuring high damping properties.

As illustrated inFIG. 5A, an upper surface of the membrane has a first inclined portion30awhich comes into contact with the lower portion of the moving closure130that constitutes the one-way closure means100, an orifice32, which has a second inclined portion30bthat comes into contact with the body110, is installed on a lower surface of the membrane30, and the first and second inclined surfaces30aand30bare inclined toward the hole31.

FIG. 4Ais a view for explaining various flow paths, andFIGS. 4A and 4Bare views illustrating a state in which the one-way closure means is installed in an orifice formed in the membrane. As illustrated inFIG. 4A, a first flow path L1is formed in the membrane30to send the fluid in the upper liquid chamber to the lower liquid chamber, the hole31formed at the center is used as a second flow path L2. As illustrated inFIG. 4A, a plurality of protrusions321and a plurality of holes322formed between the first and second flow paths L1and L2provide third flow paths L3. As illustrated inFIG. 4A, the plurality of protrusions321extend from the orifice32.

In this case, the protrusions have various shapes and heights, such that low dynamic characteristics may be implemented in accordance with the heights and the shapes of the protrusions.

A metal material may be inserted into any one or both of the body110and the column portion120that constitute the one-way closure means100, thereby allowing the one-way closure means100to serve as a dynamic damper.

With this performance, a resonance region of the mount is shifted to a low frequency band, such that it is easier to separate the resonance region from a vehicle vibratory frequency.

Therefore, as illustrated inFIGS. 4A and 4B, in the hydraulic mount having a unidirectional damping membrane according to embodiments of the present invention, the three flow paths, that is, the first flow path L1, the second flow path L2, and the third flow path L3are formed in the membrane30, such that it is possible to ensure dynamic characteristics and a loss factor in a low frequency region by adjusting lengths and sizes of the flow paths when the fluid flows through the first flow path L1.

FIG. 5Ais a view illustrating a state in which a fluid flows from an upper liquid chamber to a lower liquid chamber, andFIG. 5Bis a view illustrating a state in which the one-way closure means is raised to close the flow path.

As illustrated inFIGS. 5A and 5B, the one-way closure means100is installed in the hole31formed at the center of the membrane30, such that when the fluid flows through the second flow path L2, the fluid may flow from the upper liquid chamber to the lower liquid chamber, but a flow of the fluid from the lower liquid chamber to the upper liquid chamber is blocked, thereby ensuring a high loss factor.

That is, as illustrated inFIG. 5B, the ring-shaped protrusions111formed on the body110tightly block the lower inclined surface30bof the orifice32, such that an additional flow path in the arrow direction is blocked, thereby ensuring a high damping performance in accordance with an inertia damper.

Therefore, it is possible to obtain low dynamic characteristics and a high loss factor in an intermediate frequency region.

The plurality of protrusions formed on the orifice32has different shapes and different heights, such that when the fluid flows through the third flow path L3, the fluid flows intermittently. This flow of the fluid may implement low dynamic characteristics, and this method is identical to a method of implementing a performance of a fluid mount that constitutes the existing floating type membrane.

The metal material may be inserted into any one or both of the body110and the column portion120that constitute the one-way closure means100, thereby allowing the one-way closure means100to serve as a dynamic damper. With this performance, a resonance region of the mount is shifted to a low frequency band, such that it is easier to separate the resonance region from a vehicle vibratory frequency.

While the present invention has been described with reference to its embodiments and the accompanying drawings, different embodiments may be implemented within the spirit and the scope of the present invention. Therefore, it should be construed that the scope of the present invention is defined by the appended claims, and not limited to a particular embodiment disclosed in the present specification.