A vibration-damping device (10) includes a first attachment member (11), a second attachment member (12), an elastic body, and a partitioning member (16). A limiting passage (30) that allows a main liquid chamber (14) and an auxiliary liquid chamber (15) to communicate with each other is formed in the partitioning member (16). An inner peripheral surface of the limiting passage (30) is provided with a flow changing protrusion (31) that protrudes toward an inner side in a radial direction of the limiting passage (30) and that changes the flow of a liquid (L) that flows into the limiting passage (30) from the main liquid chamber (14) and flows through the limiting passage (30) in an axial direction of the limiting passage (30). In a vertical cross-sectional view passing through an axis of the limiting passage (30) and through the flow changing protrusion (31), the limiting passage (30) and the flow changing protrusion (31) have symmetrical shapes with respect to the axis. A protruding end of the flow changing protrusion (31) forms an inner peripheral edge of a passage hole (31c) that is open on both sides in the axial direction.

TECHNICAL FIELD

The present invention relates to a vibration-damping device that is applied to, for example, automobiles, industrial machines, or the like, and absorbs and damps vibrations of vibration generating parts, such as engines.

Priority is claimed on Japanese Patent Application No. 2014-094160, filed on Apr. 30, 2014, the content of which is incorporated herein by reference.

BACKGROUND ART

For this type vibration-damping device, conventionally, a configuration including a tubular first attachment member that is coupled to any one of a vibration generating part and a vibration receiving part, a second attachment member that is coupled to the other thereof, an elastic body that couples the first attachment member and the second attachment member together, and a partitioning member that partitions a liquid chamber within the first attachment member having a liquid enclosed therein into a main liquid chamber having the elastic body as a portion of a wall surface thereof, and an auxiliary liquid chamber is known. A limiting passage that allows the main liquid chamber and the auxiliary liquid chamber to communicate with each other is formed in the partitioning member. In this vibration-damping device, when vibration is input, the vibration is absorbed and dampened by the first attachment member and the second attachment member being displaced relative to each other while the elastic body being elastically deforming and the liquid pressure of the main liquid chamber being fluctuated such that the liquid is circulated through the limiting passage.

In this vibration-damping device, when a load is input in a reverse direction due to the rebound of the elastic body, or the like after a large load (vibration) is input, due to, for example, irregularities of a road surface, or the like, and the liquid pressure of the main liquid chamber has increased rapidly, the main liquid chamber may have a negative pressure. Then, there is a possibility, for example, that abnormal noise resulting from cavitation collapse caused by generation of a negative pressure may be generated, or a load may be applied to the first attachment member and other components that constitute the other vibration-damping device.

Thus, for example as in a vibration-damping device shown in Patent Document 1, a configuration in which generation of a negative pressure in the main liquid chamber is prevented even when a large amplitude of vibration is input by providing a valve body within the limiting passage is known.

CITATION LIST

Patent Document

SUMMARY OF INVENTION

Technical Problem

However, since the valve body is provided in the above related-art vibration-damping device, the structure thereof is complicated, and tuning of the valve body is also difficult. Additionally, for example when the valve body is opened suddenly, there is a possibility that damping performance may be affected, or desired properties may not obtained when the valve body deteriorates with the passage of time. Moreover, when the main liquid chamber has a negative pressure, there are also possibilities that abnormal noise, such as a striking sound accompanying, for example, the opening and closing of the valve body, may be generated and ride quality performance may be affected.

The present invention is made in view of the aforementioned circumstances, and an object thereof is to provide a vibration-damping device due to a simple structure that can be easily manufactured, and can prevent generation of a negative pressure in a main liquid chamber, and can exhibit a stable damping performance for a prolonged period of time while generation of abnormal noise is reduced.

Solution to Problem

A first aspect of the present invention is a vibration-damping device including a tubular first attachment member coupled to any one of a vibration generating part and a vibration receiving part, and a second attachment member coupled to the other thereof; an elastic body that couples the first attachment member and the second attachment member together; and a partitioning member that partitions a liquid chamber within the first attachment member having a liquid enclosed therein into a main liquid chamber having the elastic body as a portion of a wall surface thereof, and an auxiliary liquid chamber. A limiting passage that allows the main liquid chamber and the auxiliary liquid chamber to communicate with each other is formed in the partitioning member. An inner peripheral surface of the limiting passage is provided with a flow changing protrusion that protrudes toward an inner side in a radial direction of the limiting passage and that changes the flow of a liquid that flows into the limiting passage from the main liquid chamber and flows through the limiting passage in an axial direction of the limiting passage. In a vertical cross-sectional view passing through an axis of the limiting passage and through the flow changing protrusion, the limiting passage and the flow changing protrusion assume a symmetrical shape with respect to the axis. A protruding end of the flow changing protrusion forms an inner peripheral edge of a passage hole that is open on both sides in the axial direction.

Advantageous Effects of Invention

According to the vibration-damping device related to the present invention, manufacturing can be easily performed due to a simple structure, generation of a negative pressure in the main liquid chamber can be prevented, and a stable damping performance can be exhibited for a prolonged period of time while generation of abnormal noise is reduced.

DESCRIPTION OF EMBODIMENTS

First Embodiment

A first embodiment of a vibration-damping device related to the present invention will be described below, with reference toFIGS. 1 to 7.

The vibration-damping device10, as is shown inFIG. 1, includes a tubular first attachment member11that is coupled to any one of a vibration generating part and a vibration receiving part, a second attachment member12that is coupled to the other thereof, an elastic body13that couples the first attachment member11and the second attachment member12together, and a partitioning member16that partitions a liquid chamber within the first attachment member11in which a liquid L is enclosed, into a main liquid chamber (first liquid chamber)14that has the elastic body13in a portion of a wall surface thereof, and an auxiliary liquid chamber (second liquid chamber)15.

InFIG. 1, the second attachment member12is formed in a pillar shape, the elastic body13is formed in a tubular shape, and the first attachment member11, the second attachment member12, and the elastic body13are disposed coaxially with a common axis. Hereinafter, this common axis is referred to as an axis O (an axis of the first attachment member), a main liquid chamber14side in a direction of the axis O is referred to as a first side, an auxiliary liquid chamber15side is referred to as a second side, a direction orthogonal to the axis O is referred to as a radial direction, and a direction going around the axis O is referred to as a circumferential direction.

In addition, in a case where the vibration-damping device10is mounted on, for example, an automobile, the second attachment member12is coupled to an engine serving as the vibration generating part and the first attachment member11is coupled to a vehicle body serving as the vibration receiving part via a bracket (not shown), whereby vibration of the engine is restrained from being transmitted to the vehicle body. The vibration-damping device10is of a liquid-enclosed type in which, for example, the liquid L, such as ethylene glycol, water, or silicone oil, is enclosed in the above liquid chamber of the first attachment member11.

The first attachment member11includes a first outer tube body21located on a first side of the first attachment member11in the direction of the axis O, and a second outer tube body22located on a second side of the first attachment member11in the direction of the axis O.

The elastic body13is coupled to a first end of the first outer tube body21in a liquid-tight state, and a first opening of the first outer tube body21is blocked by the elastic body13. A second end21aof the first outer tube body21is formed with a greater diameter than other portions. The inside of the first outer tube body21is the main liquid chamber14. The liquid pressure of the main liquid chamber14fluctuates when the elastic body13is deformed and the internal volume of the main liquid chamber14varies at the time of the input of vibration.

In addition, an annular groove21bthat extends continuously over the entire circumference thereof is formed in the portion of the first outer tube body21that is connected from a second side opposite to the portion thereof to which the elastic body13is coupled.

A diaphragm17is coupled to a second end of the second outer tube body22in a liquid-tight state, and a second opening of the second outer tube body22is blocked by the diaphragm17. A first end22aof the second outer tube body22is formed with a greater diameter than other portions, and is fitted into the second end21aof the first outer tube body21. Additionally, the partitioning member16is fitted into the second outer tube body22, and the portion of the inside of the second outer tube body22between the partitioning member16and the diaphragm17is the auxiliary liquid chamber15. The auxiliary liquid chamber15has the diaphragm17as a portion of a wall surface thereof, and is expanded and contracted when the diaphragm17is deformed. In addition, substantially the entire region of the second outer tube body22is covered by a rubber membrane formed integrally with the diaphragm17.

A female thread part12ais formed coaxially with the axis O in a first end surface of the second attachment member12. The second attachment member12protrudes from the first attachment member11to the first side. A flange part12bthat protrudes toward an outer side in the radial direction and continuously extends over the entire circumference thereof is formed in the second attachment member12. The flange part12bis separated from a first end edge of the first attachment member11to the first side.

The elastic body13is formed of, for example, a rubber material or the like capable of being elastically deformed, and is formed in a tubular shape that has a gradually enlarged diameter from the first side toward the second side. A first end of the elastic body13is coupled to the second attachment member12, and a second end thereof is coupled to the first attachment member11.

In addition, substantially the entire region of an inner peripheral surface of the first outer tube body21of the first attachment member11is covered by the rubber membrane formed integrally with the elastic body13.

As shown inFIGS. 1 to 4, the partitioning member16includes a body part16aand a fitting part16b. The body part16ais formed in a bottomed tubular shape disposed coaxially with the axis O, and is fitted into the first attachment member11. The body part16ais provided with a flange part16cthat protrudes toward the outer side in the radial direction. The flange part16cis provided at a first end of the body part16a. The flange part16cis disposed within a first end22aof the second outer tube body22.

The fitting part16bis formed in a shape of a column disposed coaxially with the axis O, and is fitted into the body part16a. An end surface of the fitting part16bthat faces the first side is flush with an end surface of the body part16athat faces the first side. The size of the fitting part16bin the direction of the axis O is equal to the size of a bottom part of the body part16ain the direction of the axis O.

As shown inFIGS. 1 to 6, the partitioning member16is provided with a limiting passage30that allows the main liquid chamber14and the auxiliary liquid chamber15communicate with each other, and the main liquid chamber14and the auxiliary liquid chamber15communicate with each other only through the limiting passage30. The limiting passage30causes liquid column resonance (resonance) with respect to an ordinary magnitude of vibration assumed to be input from the vibration generating part, that is, input of an ordinary vibration, such as an idle vibration (for example, the frequency thereof is 18 Hz to 30 Hz and the amplitude thereof is ±0.5 mm or less), or an engine shake vibration (for example, the frequency thereof is 14 Hz or less, and the amplitude thereof is greater than ±0.5 mm) of which the frequency is lower than the idle vibration. The resonant frequency of the limiting passage30is the frequency of the ordinary vibration. The resonant frequency of the limiting passage30is set (tuned) on the basis of, for example, the flow passage length and the flow passage cross-sectional area of the limiting passage30.

As shown inFIGS. 4 to 6, the limiting passage30includes a main opening30a, a linear passage part30b, a circumferential groove part30c, and a sub-opening30d, which are lined up in this order from a main liquid chamber14side toward the auxiliary liquid chamber15side in an axial direction of the limiting passage30.

The main opening30aextends from an end surface of the partitioning member16that faces the first side toward the second side thereof, and linearly extends in the direction of the axis O in the example shown. The main opening30ais disposed at a position offset with respect to the axis O. The second end of the main opening30adoes not reach an end surface of the partitioning member16that faces the second side, and the main opening30ais a not open on the other side.

The linear passage part30bextends from the second end of the main opening30atoward a direction along an orthogonal plane orthogonal to the axis O, and is open from an outer peripheral surface of the partitioning member16. The linear passage part30blinearly extends along the above orthogonal plane. The linear passage part30bis formed in a columnar shape, and an axis (hereinafter a “flow passage axis”) M of the linear passage part30bis located on the above orthogonal plane.

The circumferential groove part30cextends in a circumferential direction from an end of the linear passage part30bthat is open on the outer peripheral surface of the partitioning member16. The circumferential groove part30cextends in the circumferential direction in the outer peripheral surface of the partitioning member16, and is blocked from the outer side in the radial direction by an inner peripheral surface of the first attachment member11.

The sub-opening30dextends from an end of the circumferential groove part30con the auxiliary liquid chamber15side toward the second side, and is open on an end surface of the partitioning member16that faces the second side.

The main opening30aof the limiting passage30is formed only in the fitting part16bof the partitioning member16, and the circumferential groove part30cand the sub-opening30dare formed only in the body part16aof the partitioning member16. The linear passage part30bof the limiting passage30includes a first groove part30eformed in the body part16a, and a second groove part30fformed in the fitting part16b.

The first groove part30eis formed in an end surface of the bottom part of the body part16athat faces the first side, and the second groove part30fis formed in an end surface of the fitting part16bthat faces the second side. The first groove part30eand the second groove part30fare formed with the same shape as each other and the same size as each other.

In addition, as shown inFIG. 4, the first groove part30eis formed over the entire length in an axis direction (hereinafter “a flow passage axis M direction”) of the linear passage part30bin the bottom part of the body part16a, and both ends of the linear passage part30bin the flow passage axis M direction communicate with the circumferential groove part30c. As shown inFIGS. 5 and 6, a first end of the first groove part30ein the flow passage axis M direction is connected to an end of the circumferential groove part30cin the circumferential direction, and a second end thereof in the flow passage axis M direction is connected to an intermediate part located between both ends of the circumferential groove part30cin the circumferential direction. A portion of the first groove part30elocated on a first end side in the flow passage axis M direction constitutes the linear passage part30b, and a protruding part16dthat protrude from the fitting part16btoward the second side is liquid-tightly fitted into a portion of the first groove part30elocated on the second end side in the flow passage axis M direction. The protruding part16drestricts that the linear passage part30bis short-circuited to the above intermediate part of the circumferential groove part30c.

In the present embodiment, as shown inFIGS. 5 to 7, an inner peripheral surface of the limiting passage30is provided with a flow changing protrusion31that changes the flow of the liquid L that flows into the limiting passage30from the main liquid chamber14.

The flow changing protrusion31protrudes from the inner peripheral surface of the limiting passage30toward a radial inner side of the limiting passage30, and changes the flow of the liquid L that flows into the limiting passage30from the main liquid chamber14and flows through the limiting passage30in the axial direction of the limiting passage30. The flow changing protrusion31makes the liquid L that flows through the limiting passage30flow along the surface of the flow changing protrusion31, thereby bending the flow of the liquid L. The flow changing protrusion31is formed integrally with the partitioning member16as a rigid body having rigidity such that the flow changing protrusion31is not deformed when the flow of the liquid L is received using, for example, a resin material or the like.

The flow changing protrusion31is provided within the linear passage part30bover the entire length in the flow passage axis M direction, and changes the flow of the liquid L that flows through the linear passage part30bin the flow passage axis M direction, to a radial direction (hereinafter a “flow passage radial direction”) of the linear passage part30b.

Additionally, in the present embodiment, as shown inFIGS. 5 and 6, the limiting passage30and the flow changing protrusion31have a symmetrical shape with respect to the flow passage axis M in a vertical sectional view passing through the flow passage axis M and the flow changing protrusion31. The limiting passage30and the flow changing protrusion31are linearly symmetrical as the flow passage axis M as a reference in the above vertical sectional view. The flow changing protrusion31is disposed over the entire circumference of the flow passage axis M, and continuously extends over the entire circumference of the flow passage axis M in the example shown.

The flow changing protrusion31is formed in a tubular shape that extends in the flow passage axis M direction, and is formed in a cylindrical shape in the example shown. A first end of the flow changing protrusion31located on the auxiliary liquid chamber15side in the flow passage axis M direction is a base end (fixed end) coupled to the inner peripheral surface of the limiting passage30, and a second end thereof in the flow passage axis M direction is a protruding end (free end) non-coupled to the inner peripheral surface of the limiting passage30. A passage hole31cthat is an opening on a protruding end (free end) side of the flow changing protrusion31faces the main liquid chamber14side in the flow passage axis M direction.

An outer peripheral surface of the flow changing protrusion31gradually decreases in diameter from the base end toward the protruding end, and is linearly inclined with respect to the flow passage axis M in the above vertical sectional view. In addition, in the present embodiment, an inner peripheral surface of the flow changing protrusion31also gradually decreases in diameter from the base end toward the protruding end, and the overall flow changing protrusion31gradually decreases in diameter from the base end toward the protruding end.

The protruding end of the flow changing protrusion31forms an inner peripheral edge of the passage hole31cthat is open on both sides in the flow passage axis M direction. In the example shown, the overall opening on a protruding end side of the flow changing protrusion31is the passage hole31c, and the protruding end of the flow changing protrusion31constitutes the overall inner peripheral edge of the passage hole31c.

The flow changing protrusion31partitions the inside of the limiting passage30into a flow changing space31awhere the flow of the liquid L that flows into the limiting passage30is changed, and a passage space31bthrough which the liquid L that flows into the limiting passage30is passed. The flow changing protrusion31forms the flow changing space31abetween the flow changing protrusion31and an inner peripheral surfaces of the limiting passage30, and the flow changing space31ais formed between the outer peripheral surface of the flow changing protrusion31and an inner peripheral surface of the linear passage part30bthat is the inner peripheral surface of the limiting passage30. The outer peripheral surface of the flow changing protrusion31is a defining surface that defines the flow changing space31a, and this defining surface is inclined with respect to the flow passage axis M in the above vertical sectional view.

The flow changing space31ais formed in a ring shape coaxial with the flow passage axis M, and is open on the main liquid chamber14side in the flow passage axis M direction. In the above vertical sectional view, the space width of the flow changing space31ain the flow passage radial direction gradually decreases from the main liquid chamber14side toward the auxiliary liquid chamber15side in the flow passage axis M direction. A bottom surface of the flow changing space31afaces the main liquid chamber14side in the flow passage axis M direction and couples together the outer peripheral surface of the flow changing protrusion31and the inner peripheral surface of the linear passage part30b. In the above vertical sectional view, the bottom surface of the flow changing space31ais formed in the shape of a concavely curved surface that becomes concave toward the auxiliary liquid chamber15side in the flow passage axis M direction.

The passage space31bincludes the passage hole31c. The passage space31bis formed by the inner peripheral surface of the flow changing protrusion31, and is constituted by the overall inside of the flow changing protrusion31. The passage space31bis formed in the shape of a frustum coaxial with the flow passage axis M, and in the example shown, in the shape of a truncated cone, and is open on both sides in the flow passage axis M direction. The passage space31bis gradually increased in diameter from the main liquid chamber14side toward the auxiliary liquid chamber15side in the flow passage axis M direction.

In addition, in the example shown, the flow changing protrusion31is split into two in the direction of the axis O, and each flow changing protrusion31is constituted of a first split protrusion32aon the second side, and a second split protrusion32bon the first side. The first split protrusion32aand the second split protrusion32bare formed with the same shape as each other and with the same size as each other, and the flow changing protrusion31is equally divided into two in the direction of the axis O along the above orthogonal plane. The first split protrusion32ais disposed within the first groove part30eand is formed integrally with the body part16a, and the second split protrusion32bis disposed within the second groove part30fand is formed integrally with the fitting part16b.

In the vibration-damping device10, when vibration is input, the first attachment member11and the second attachment member12are displaced relative to each other while elastically deforming the elastic body13and the liquid pressure of the main liquid chamber14fluctuates. Accordingly, the liquid L flows into the limiting passage30from the main liquid chamber14, and flows between the main liquid chamber14and the auxiliary liquid chamber15through the limiting passage30. When the liquid L flows into the linear passage part30bfrom the main opening30aof the limiting passage30, flows through the linear passage part30bin the flow passage axis M direction, and reaches a portion within the linear passage part30bwhere the flow changing protrusion31is located, the liquid L that flows through an outer side in the flow passage radial direction within the linear passage part30bof the liquid L that flows through the linear passage part30b, flows into the flow changing space31a, flows toward the protruding end side of the flow changing protrusion31along the surface of the flow changing protrusion31, and flow is changed to an inner side in the flow passage radial direction. In this case, by changing the flow of the liquid L that flows into the flow changing space31aso as to run along the outer peripheral surface of the flow changing protrusion31, the liquid L can be swirled with a circumference extending around the flow passage axis M as a swirling axis. Additionally, the liquid L that flows through the inner side in the flow passage radial direction within the linear passage part30bof the liquid L that flows through the linear passage part30b, passes through the passage hole31cin the flow passage axis M direction.

In this case, if the flow speed of the liquid L is increased, the pressure loss of the liquid L is raised due to, for example, an energy loss resulting from the collision between the liquid L that passes through the passage hole31cin the flow passage axis M direction, and the liquid L, the flow of which is changed by the flow changing protrusion31, an energy loss caused by changing the viscous resistance of the liquid L and the flow of the liquid L and forming a swirling flow, an energy loss caused by the friction between the liquid L and the flow changing protrusion31, or the like.

Here, in the vibration-damping device10, the limiting passage30and the flow changing protrusion31have a symmetrical shape with respect to the flow passage axis M in the above vertical sectional view. Thus, in this vertical sectional view, the flows of the respective liquids L that flow through portions located on both outsides in the flow passage radial direction are symmetrically changed with respect to the flow passage axis M by the flow changing protrusion31. Since the liquid L, the flow of which is changed in this way collides against the liquid L that passes through the passage hole31cin the flow passage axis M direction, from outside in both flow passage radial directions, the pressure loss of the liquid L is increased effectively.

On the other hand, if the flow speed of the liquid L is low, the pressure loss of the liquid L caused by the collision between the above liquids L as mentioned above is suppressed, and the liquid L smoothly flows through the limiting passage30.

When an ordinary vibration, such as an engine shake vibration or an idle vibration, is input to the vibration-damping device10, compared to a case where large vibration with a larger amplitude than this ordinary vibration is input, the quantity of the liquid L that flows into the limiting passage30from the main liquid chamber14per unit time becomes small, and the flow speed of the liquid L that flows through the limiting passage30is suppressed. Therefore, the pressure loss of the liquid L is suppressed as mentioned above, it is possible to smoothly circulate the liquid L within the limiting passage30to make the liquid actively communicate between the main liquid chamber14and the auxiliary liquid chamber15. As a result, resonance can be caused within the limiting passage30, and this vibration can be absorbed and dampened effectively.

On the other hand, when large vibration is input to the vibration-damping device10, the quantity of the liquid that flows into the limiting passage30from the main liquid chamber14per unit time becomes large. As a result, since the flow speed of the liquid L that flows into the limiting passage30from the main liquid chamber14is increased, a large pressure loss can be caused in the liquid L as mentioned above. Accordingly, it is possible to reduce the flow speed of the liquid L that flows into the limiting passage30from the main liquid chamber14and to suppress the liquid L from flowing through the limiting passage30between the main liquid chamber14and the auxiliary liquid chamber15. As a result, liquid pressure fluctuation of the main liquid chamber14can be suppressed, and generation of a local negative pressure in the main liquid chamber14can be prevented.

Moreover, since a large pressure loss can be caused in the liquid L that flows into the limiting passage30from the main liquid chamber14, it is possible to limit the liquid L from flowing into the limiting passage30from the main liquid chamber14when a load in a direction in which the liquid pressure of the main liquid chamber14increases is input in a process in which a large vibration is input to the vibration-damping device10. Accordingly, it is possible to enlarge the positive pressure within the main liquid chamber14. As a result, it is possible to prevent the negative pressure within the main liquid chamber14from becoming large when a load in a direction in that the liquid pressure of the main liquid chamber14falls is input next.

As described above, according to the vibration-damping device10related to the present embodiment, the flow changing protrusion31is provided instead of the valve body like the above related art. Thus, when ordinary vibration is input, this vibration is absorbed and dampened, and when a large vibration is input, it is possible to prevent generation of a negative pressure in the main liquid chamber14, manufacturing can be easily performed due to a simple structure, and a stable damping performance can be exhibited for a prolonged period of time.

Additionally, in the vibration-damping device10, it is not necessary to install a movable member like the valve body shown in the above related art, it is possible to reduce abnormal noise resulting from generation of a negative pressure in the main liquid chamber14, such as abnormal noise accompanying the operation of the movable member or generation of striking sound occurring between the movable member and a fixing member to which this movable member is fixed. As a result, the vibration-damping device10that is excellent in ride quality performance can be provided.

Additionally since the flow changing protrusion31partitions the inside of the limiting passage30into the flow changing space31aand the passage space31b, it is possible to limit the influence from the liquid L that passes through the passage space31b, thereby precisely changing the flow of the liquid L that has flowed into the flow changing space31a. As a result, when the flow speed of the liquid L is increased, the pressure loss of the liquid L can be increased reliably.

Additionally, since the flow changing space31ais formed between the outer peripheral surface of the flow changing protrusion31and the inner peripheral surface of the limiting passage30, the flow changing space31acan be formed over the entire circumference of the flow passage axis M. Accordingly, the flow of the liquid L that flows through the outer side in the flow passage radial direction within the linear passage part30bof the liquid L that flows through the linear passage part30b, can be changed over the entire circumference of the flow passage axis M. As a result, when the flow speed of the liquid L is increased, the pressure loss of the liquid L can be increased much more reliably.

Additionally, since the passage space31bis formed by the inner peripheral surface of the flow changing protrusion31, the passage space31bcan be made to be open on both sides in the flow passage axis M direction. Accordingly, it is possible to circulate the liquid L that passes through the passage space31bin the flow passage axis M direction within the passage space31b. As a result, the liquid L can be smoothly circulated within the passage space31b.

Additionally, the outer peripheral surface of the flow changing protrusion31gradually decreases in diameter from the base end toward the protruding end. Therefore, by changing the flow of the liquid L that flows into the flow changing space31aso as to run along the outer peripheral surface of the flow changing protrusion31, the liquid L can be swirled with the circumference extending around the flow passage axis M as a swirling axis, and the direction of flow of the liquid L can be reversed in the flow passage axis M direction. Accordingly, the pressure loss of the liquid L caused when the liquid L that passes through the passage hole31cin the flow passage axis M direction collides against the liquid L, the flow of which is changed by the flow changing protrusion31can be increased much more reliably.

In addition, in the present embodiment, the inner peripheral surface of the flow changing protrusion31also gradually decreases in diameter from the base end toward the protruding end, and the overall flow changing protrusion31gradually decreases in diameter from the base end toward the protruding end. Therefore, when the liquid L that flows into the passage space31bfrom the passage hole31cflows through the passage space31bin the flow passage axis M direction, it is possible to limit the energy loss resulting from the friction between this liquid L and the inner peripheral surface of the flow changing protrusion31. As a result, the liquid L can be still more smoothly circulated within the passage space31b.

Second Embodiment

Next, a second embodiment of the vibration-damping device related to the present invention will be described with reference toFIGS. 8 and 9.

In addition, in the second embodiment, the same portions as the constituent elements in the first embodiment will be designated by the same reference signs and a description thereof will be omitted, and only different points will be described.

In the vibration-damping device of the present embodiment, a flow changing protrusion36is formed in a plate shape that protrudes from the inner peripheral surface of the limiting passage30, instead of being formed in a tubular shape that extends in the flow passage axis M direction. The flow changing protrusion36is intermittently disposed over the entire circumference of the flow passage axis M, and a pair of the flow changing protrusions are formed with the flow passage axis M being interposed therebetween in the example shown. The flow changing protrusions36are formed with the same shape as each other and with the same size as each other.

As shown inFIG. 9, each flow changing protrusion36assumes a semicircular shape in a cross-sectional view of the limiting passage30orthogonal to the flow passage axis M, and an outer peripheral edge of the flow changing protrusion36is constituted of a coupling part37and a connecting part38. The coupling part37extends in a circular-arc shape around the flow passage axis M. The coupling part37is continuously coupled to the inner peripheral surface of the linear passage part30b, which is the inner peripheral surface of the limiting passage30, over the entire length around the flow passage axis M. The connecting part38extends linearly and connects both ends of the coupling part37around the flow passage axis M together. The pair of flow changing protrusions36are symmetrically disposed with the flow passage axis M being interposed therebetween in the above cross-sectional view, and the pair of entire flow changing protrusions36face each other in the flow passage radial direction.

As shown inFIG. 8, the limiting passage30and the flow changing protrusions36have a symmetrical shape with respect to the flow passage axis M in a vertical sectional view passing through the flow passage axis M and a central part of the coupling part37around the flow passage axis M. Each flow changing protrusion36protrudes being inclined in the flow passage axis M direction from the inner peripheral surface of the linear passage part30b, in the above vertical sectional view.

In this vibration-damping device, a passage hole36cis formed between protruding ends of the pair of flow changing protrusions36. The passage hole36cis formed in the shape of an elongated hole between the connecting parts38in the above cross-sectional view. Additionally, the flow changing space36ais open only on the main liquid chamber14side in the flow passage axis M direction, and is formed between the surface of each flow changing protrusion36and the inner peripheral surface of the linear passage part30b.

Moreover, the passage space36bis open on both sides in the flow passage axis M direction, and a portion of a wall surface of the passage space36bis constituted by the surface of each flow changing protrusion36.

In addition, as shown inFIG. 9, in the present embodiment, the pair of flow changing protrusions36are symmetrically disposed with the flow passage axis M being disposed therebetween in the above cross-sectional view. However, the present invention is not limited to this, and other forms in which at least portions of the pair of flow changing protrusions face each other in the flow passage radial direction may be employed.

Third Embodiment

Next, a third embodiment of the vibration-damping device related to the present invention will be described with reference toFIG. 10.

In the third embodiment, the same portions as the constituent elements in the first embodiment will be designated by the same reference signs and a description thereof will be omitted, and only different points will be described.

In the vibration-damping device of the present embodiment, a flow changing protrusion41is formed in an annular shape that is open on the flow passage axis M direction, instead of being formed in a tubular shape that extends in the flow passage axis M direction. The flow changing protrusion41continuously extends over the entire circumference around the flow passage axis M.

The flow changing protrusion41is formed such that the size thereof in the flow passage axis M direction becomes small from both sides in the flow passage axis M direction gradually from the base end toward the protruding end, assumes a triangular shape that becomes convex toward the inner side in the flow passage radial direction in the above vertical sectional view, and in the example shown inFIG. 10, an isosceles triangular shape. End surfaces of the flow changing protrusion41that face the flow passage axis M direction are all inclined surface that are inclined with respect to the flow passage axis M, in the above vertical sectional view.

In this vibration-damping device, a passage hole41cis the inside of the flow changing protrusion41, and the above flow changing space and the above passage space are not partitioned within the linear passage part30b. The inside of the linear passage part30bis partitioned into a pair of partition spaces41aby the flow changing protrusion41. The partition spaces41aare located on both sides with the flow changing protrusion41being disposed therebetween in the flow passage axis M direction, and communicate with each other through the passage hole41c.

When vibration is input to this vibration-damping device and the liquid L flows through the limiting passage30between the main liquid chamber14and the auxiliary liquid chamber15, the liquid L that flows through the outer side in the flow passage radial direction within the linear passage part30bof the liquid L that flows through the linear passage part30b, flows from the base end toward the protruding end along the end surfaces of the flow changing protrusion41, and thereby the flow of the liquid is changed to the inner side in the flow passage radial direction. Additionally, the liquid L that flows through the inner side in the flow passage radial direction within the linear passage part30bof the liquid L that flows through the linear passage part30b, passes through the passage hole41cin the flow passage axis M direction.

Accordingly, if the flow speed of the liquid L is increased, the pressure loss of the liquid L is raised due to, for example, an energy loss resulting from the collision between the liquid L that passes through the passage hole41cin the flow passage axis M direction, and the liquid L, the flow of which is changed by the flow changing protrusion41. In this case, the liquid L does not easily flow into a region of the linear passage part30bbetween a two-dot chain line shown inFIG. 10and the inner peripheral surface of the linear passage part30b, and separation of a flow occurs. Therefore, the pressure loss of the liquid L is increased even by the effective sectional area of the limiting passage30decreasing within the partition spaces41aof the linear passage part30b.

Fourth Embodiment

Next, a fourth embodiment of the vibration-damping device related to the present invention will be described with reference toFIG. 11.

In addition, in the fourth embodiment, the same portions as the constituent elements in the third embodiment will be designated by the same reference signs and a description thereof will be omitted, and only different points will be described.

In the vibration-damping device of the present embodiment, a flow changing protrusion42is formed in a trapezoidal shape that becomes convex toward the inner side in the flow passage radial direction, and in the example shown inFIG. 11, in the shape of an isosceles trapezoid, in the above vertical sectional view. The passage hole42cis formed in a columnar shape.

Even in this vibration-damping device, similar to the vibration-damping device related to the above third embodiment, separation of a flow occurs, the liquid L does not easily flow into a region of the linear passage part30bbetween a two-dot chain line shown inFIG. 11and the inner peripheral surface of the linear passage part30b, and the effective sectional area of the limiting passage30decreases. Here, in the present embodiment, since the passage hole42cis formed in a columnar shape, separation of the liquid occurs in both of the partition space42aand the passage hole42cof the linear passage part30b, and the pressure loss of the liquid L is increased effectively.

Fifth Embodiment

Next, a fifth embodiment of the vibration-damping device related to the present invention will be described with reference toFIG. 12.

In addition, in the fifth embodiment, the same portions as the constituent elements in the third embodiment will be designated by the same reference signs and a description thereof will be omitted, and only different points will be described.

In the vibration-damping device of the present embodiment, a pair of flow changing protrusions43and44is provided at a distance from each other in the flow passage axis M direction within the linear passage part30b, and an intermediate part of the linear passage part30bin the flow passage axis M direction, which is located between the flow changing protrusions43and44, has a greater diameter than each portion located on the outside in the flow passage axis M direction with respect to this intermediate part.

The flow changing protrusions43and44are formed in the shape of a right-angled triangle that becomes convex toward the inner side in the flow passage radial direction, in the above vertical sectional view. End surfaces of the flow changing protrusions43and44are provided with inclined end surfaces43aand44athat are inclined with respect to the flow passage axis M in the above vertical sectional view, and orthogonal end surfaces43band44bthat are orthogonal to the flow passage axis M in the above vertical sectional view.

Here, in the present embodiment, one first flow changing protrusion43and one second flow changing protrusion44are provided as the above flow changing protrusion. The first flow changing protrusion43is provided on the main liquid chamber14side in the flow passage axis M direction, and the inclined end surface43aof the first flow changing protrusion43faces the main liquid chamber14side in the flow passage axis M direction. A first passage hole43cserving as the above passage hole is provided inside the first flow changing protrusion43. The second flow changing protrusion44is provided on the auxiliary liquid chamber15side in the flow passage axis M direction, and the inclined end surface44aof the second flow changing protrusion44faces the auxiliary liquid chamber15side in the flow passage axis M direction. The second passage hole44cserving as the above passage hole is provided inside the second flow changing protrusion44.

When vibration is input to this vibration-damping device and the liquid L flows through the limiting passage30from the main liquid chamber14toward the auxiliary liquid chamber15, the liquid L that flows through the outer side in the flow passage radial direction within the linear passage part30bof the liquid L that has flowed into the linear passage part30bfrom the main opening30a, flows from the base end toward the protruding end along the inclined end surface43aof the first flow changing protrusion43. Therefore, the flow of the liquid L is changed toward the inner side in the flow passage radial direction. Additionally, the liquid L that flows through the inner side in the flow passage radial direction within the linear passage part30bof the liquid L that has flowed into the linear passage part30b, passes through the first passage hole43cin the flow passage axis M direction.

Accordingly, if the flow speed of the liquid L is increased, the pressure loss of the liquid L is increased due to, for example, an energy loss resulting from the collision between the liquid L that has flowed into the first passage hole43cin the flow passage axis M direction, and the liquid L, the flow of which is changed by the first flow changing protrusion43, reduction (refer to a two-dot chain line shown inFIG. 12) of effective sectional area resulting from separation of a flow in the intermediate part of the linear passage part30bin the flow passage axis M direction, or the liked.

Here, the intermediate part of the linear passage part30bin the flow passage axis M direction has a greater diameter than other portions. Thus, if the liquid L passes through the first passage hole43cand flows into the intermediate part of the linear passage part30b, the liquid L that flows through the outer side in the flow passage radial direction within the linear passage part30bof the above liquid L, flows in the flow passage axis M direction, widening to the outer side in the flow passage radial direction so as to run along an inner peripheral surface of the intermediate part. As a result, when the liquid L passes through the second passage hole44cfrom the intermediate part, the liquid L that flows through the outer side in the flow passage radial direction within the linear passage part30bof the above liquid L, flows from the base end toward the protruding end along the orthogonal end surface44bof the second flow changing protrusion44, and thereby the flow of the liquid L is changed toward the inner side in the flow passage radial direction.

Accordingly, if the flow speed of the liquid L is increased, the pressure loss of the liquid L is increased due to, for example, an energy loss resulting from the collision between the liquid L that passes through the second passage hole44cin the flow passage axis M direction, and the liquid L, the flow of which is changed by the second flow changing protrusion44.

Sixth Embodiment

Next, a sixth embodiment of the vibration-damping device related to the present invention will be described with reference toFIG. 13.

In the sixth embodiment, the same portions as the constituent elements in the fifth embodiment will be designated by the same reference signs and a description thereof will be omitted, and only different points will be described.

In the vibration-damping device of the present embodiment, the flow changing protrusions43and44are formed in a rectangular shape, instead of being formed in a right-angled triangle shape that becomes convex toward the inner side in the flow passage radial direction, in the above vertical sectional view.

Both end surfaces of the flow changing protrusions43and44are respectively the orthogonal end surfaces43band44b. The first passage hole43cis provided over the entire length in the flow passage axis M direction of the first flow changing protrusion43, within the first flow changing protrusion43. The second passage hole44cis provided over the entire length in the flow passage axis M direction of the second flow changing protrusion44, within the second flow changing protrusion44. The first passage hole43cand the second passage hole44chave the same diameter over the entire length in the flow passage axis M direction. The first passage hole43chas a greater diameter than the second passage hole44c.

When vibration is input to this vibration-damping device and the liquid L flows through the limiting passage30from the main liquid chamber14toward the auxiliary liquid chamber15, the liquid L that flows through the outer side in the flow passage radial direction within the linear passage part30bof the liquid L that has flowed into the linear passage part30bfrom the main opening30a, flows from the base end toward the protruding end along the orthogonal end surface43bthat faces the outside in the flow passage axis M direction, in the first flow changing protrusion43, and thereby the flow of the liquid L is changed toward the inner side in the flow passage radial direction. Additionally, the liquid L that flows through the inner side in the flow passage radial direction within the linear passage part30bof the liquid L that has flowed into the linear passage part30b, passes through the first passage hole43cin the flow passage axis M direction.

Accordingly, if the flow speed of the liquid L is increased, the pressure loss of the liquid L is increased due to, for example, an energy loss resulting from the collision between the liquid L that passes through the first passage hole43cin the flow passage axis M direction, and the liquid L, the flow of which is changed by the first flow changing protrusion43.

Seventh Embodiment

Next, a seventh embodiment of the vibration-damping device related to the present invention will be described with reference toFIG. 14.

In addition, in the seventh embodiment, the same portions as the constituent elements in the first embodiment will be designated by the same reference signs and a description thereof will be omitted, and only different points will be described.

In the vibration-damping device of the present embodiment, a first flow changing protrusion33and a second flow changing protrusion34are provided as the above flow changing protrusion. A first passage hole33c(passage hole) that is an opening on a protruding end (free end) side of the first flow changing protrusion33faces the main liquid chamber14side in the flow passage axis M direction, and a second passage hole34c(passage hole) that is an opening on a protruding end (free end) side of the second flow changing protrusion34faces the auxiliary liquid chamber15side in the flow passage axis M direction.

The first flow changing protrusion33is located on the main liquid chamber14side in the flow passage axis M direction, the second flow changing protrusion34is located on the auxiliary liquid chamber15side in the flow passage axis M direction, and the first flow changing protrusion33and the second flow changing protrusion34are located over the entire length in the flow passage axis M direction within the linear passage part30b. The first flow changing protrusion33and the second flow changing protrusion34are symmetrically formed in the flow passage axis M direction, and base ends (fixed end) of the first flow changing protrusion33and the second flow changing protrusion34are separated from each other in the flow passage axis M direction.

The first flow changing protrusion33partitions the inside of the linear passage part30binto a first flow changing space33aserving as the above flow changing space, and a first passage space33bserving as the above passage space.

The first flow changing space33ais formed in a ring shape coaxial with the flow passage axis M, and is open on the main liquid chamber14side in the flow passage axis M direction. In the above vertical sectional view, the space width of the first flow changing space33ain the flow passage radial direction becomes gradually smaller from the main liquid chamber14side toward the auxiliary liquid chamber15side in the flow passage axis M direction. A bottom surface of the first flow changing space33afaces the main liquid chamber14side in the flow passage axis M direction, and couples together the outer peripheral surface of the first flow changing protrusion33and the inner peripheral surface of the linear passage part30b. In the above vertical sectional view, the bottom surface of the first flow changing space33ais formed in the shape of a concavely curved surface that becomes concave toward the auxiliary liquid chamber15side in the flow passage axis M direction.

The first passage space33bis formed in the shape of a frustum coaxial with the flow passage axis M, and in the example shown, in the shape of a truncated cone, and is open on both sides in the flow passage axis M direction. The first passage space33bis gradually increased in diameter from the main liquid chamber14side toward the auxiliary liquid chamber15side in the flow passage axis M direction.

The second flow changing protrusion34partitions the inside of the linear passage part30binto a second flow changing space34aserving as the above flow changing space, and a second passage space34bserving as the above passage space.

The second flow changing space34ais formed in a ring shape coaxial with the flow passage axis M, and is open on the auxiliary liquid chamber15side in the flow passage axis M direction. In the above vertical sectional view, the space width of the second flow changing space34abecomes gradually smaller from the auxiliary liquid chamber15side toward the main liquid chamber14side in the flow passage axis M direction. A bottom surface of the second flow changing space34afaces the auxiliary liquid chamber15side in the flow passage axis M direction, and couples together the outer peripheral surface of the second flow changing protrusion34and the inner peripheral surface of the linear passage part30b. In the above vertical sectional view, the bottom surface of the second flow changing space34ais formed in the shape of a concavely curved surface that becomes concave toward the main liquid chamber14side in the flow passage axis M direction.

The second passage space34bis formed in the shape of a frustum coaxial with the flow passage axis M, and in the example shown, in the shape of a truncated cone, and is open on both sides in the flow passage axis M direction. The second passage space34bis gradually increased in diameter from the auxiliary liquid chamber15side toward the main liquid chamber14side in the flow passage axis M direction.

Eighth Embodiment

Next, an eighth embodiment of the vibration-damping device related to the present invention will be described with reference toFIG. 15.

In addition, in the eighth embodiment, the same portions as the constituent elements in the seventh embodiment will be designated by the same reference signs and a description thereof will be omitted, and only different points will be described.

In the vibration-damping device of the present embodiment, the first flow changing protrusion33and the second flow changing protrusion34are disposed adjacent to each other in the flow passage axis M direction, and the base ends of the flow changing protrusions33and34are directly connected together. The inner peripheral surfaces of the respective flow changing protrusions33and34have the same diameter over the entire length in the flow passage axis M direction, and the passage spaces33band34bare formed in a columnar shape that extends in the flow passage axis M direction. A second end of the first passage space33band a first end of the second passage space34bare directly connected together.

In this vibration-damping device, a coupled body40in which the base ends of the flow changing protrusions33and34are directly connected together is formed in a tubular shape that extends in the flow passage axis M direction. The inside of this coupled body40forms a connected space40ain which the passage spaces33band34bare connected together in the flow passage axis M direction. An inner peripheral surface of the connected space40ais smoothly continuous over the entire length in the flow passage axis M direction, and a stepped part is not formed.

In addition, the technical scope of the present invention is not limited to the above embodiments, and various changes can be made without departing from the concept of the present invention.

Additionally, in the above first, seventh, and eighth embodiments, the outer peripheral surface of the flow changing protrusion31,33, or34gradually decreases in diameter from the base end toward the protruding end. However, the present invention is not limited to this. For example, the outer peripheral surface of each flow changing protrusion may be formed in a tubular shape with the same diameter over the entire length in the flow passage axial direction, and the base end of the flow changing protrusion may be coupled to the inner peripheral surface of the first limiting passage via a flange part.

Additionally, the limiting passage30and the flow changing protrusion31,33,34,36,41,42,43, or44may not be perfect linear symmetrical with the flow passage axis M as a reference in the above vertical sectional view. For example, there may be a slight difference in the shape, size, or the like of the limiting passage and the flow changing protrusions on a first side and a second side in the flow passage radial direction with respect to the flow passage axis M, in the above vertical sectional view.

Additionally, in the above embodiment, the flow passage axis M that is a central axis of the linear passage part30bis located on the above orthogonal plane. However, the present invention is not limited to this. For example, the flow passage axis M may extend in the axis direction or may extend in the circumferential direction.

Additionally, in the present embodiments, a case where an engine is connected to the second attachment member12and the first attachment member11is connected to a vehicle body is described. However, contrary to this, the first and second attachment members may be connected.

Moreover, the vibration-damping device10related to the present invention is not limited to engine mounts of vehicles and can also be applied to those other than the engine mounts. For example, the present invention can also be applied to mounts of generators loaded on construction machines, or can also be applied to mounts of machines installed in factories or the like.

In addition, the constituent elements in the above embodiments can be substituted with well-known constituent elements without departing from the concept of the present invention, and the above embodiments may be appropriately combined together.

INDUSTRIAL APPLICABILITY

According to the vibration-damping device related to the present invention, manufacturing can be easily performed due to a simple structure, generation of a negative pressure in the main liquid chamber can be prevented, and a stable damping performance can be exhibited for a prolonged period of time while generation of abnormal noise is reduced.

REFERENCE SIGNS LIST