JP2010185549A - Vibration control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain the abrasion of a shaft engaged slidably with a piston member, and to maintain the satisfactory sliding of the piston member over a long period. <P>SOLUTION: This vibration control device 10 is configured to conduct switching between a shake orifice 31 and an idle orifice 32 having the flow resistance of a liquid lower than that of the shake orifice 31, by sliding the piston member 27 in the expansion and contraction directions of an orifice space 25 and a pressurization space 26 on the shaft 28, in accompaniment to liquid pressure fluctuation inside a main liquid chamber 14, and the shaft 28 includes the shaft body 28a formed integrally with an orifice member 21, and a hard layer 28b provided in an outer circumferential part of the shaft body 28a, and having a hardness higher than that of a material forming the shaft body 28a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vibration isolator that is applied to, for example, automobiles and industrial machines and absorbs and attenuates vibrations of a vibration generating unit such as an engine.

Conventionally, as this type of vibration isolator, a cylindrical first mounting member connected to one of the vibration generating unit and the vibration receiving unit and the other one of the vibration generating unit and the vibration receiving unit are connected. A second mounting member; a rubber elastic body that elastically connects the two mounting members; a liquid is sealed inside the first mounting member with the rubber elastic body as a part of a partition wall; A main liquid chamber whose internal volume changes due to deformation of the body, and a cylindrical partition member that is formed so that at least a part of the partition wall can be deformed and is partitioned into a sub liquid chamber in which the liquid is sealed. There is known a configuration in which an orifice passage is formed in a member to communicate a main liquid chamber and a sub liquid chamber.
Further, in recent years, the orifice passage is provided with a shake orifice and an idle orifice having a liquid flow resistance smaller than that of the shake orifice, and depending on the frequency and amplitude of the input vibration, that is, the fluctuation amount of the liquid pressure in the main liquid chamber, By switching between the shake orifice and the idle orifice, a configuration has been proposed in which the liquid flows in the shake orifice when the shake vibration is input, and the liquid flows in the idle orifice when the idle vibration is input.
As such an anti-vibration device, for example, in Patent Document 1 below, the partition member, the interior of which is part of the idle orifice and communicated with the secondary liquid chamber, is isolated from the idle orifice and is separated from the primary orifice. A pressurizing space that communicates with the liquid chamber; a piston member that is partitioned; and a shaft portion that extends along the expansion and contraction directions of the orifice space and the pressurizing space and is slidably fitted to the piston member. Proposed configurations have been proposed.
The piston member slides in the expansion / contraction direction on the shaft portion in accordance with the fluid pressure variation in the main fluid chamber, so that the shake orifice and the idle orifice are switched.

JP 2007-120598 A

  However, in the conventional vibration isolator, the wear of the shaft portion is coupled with the fact that the main liquid chamber and the sub liquid chamber are filled with a liquid having a relatively low viscosity such as ethylene glycol, water, and silicone oil. Therefore, there is a possibility that good sliding along the expansion / contraction direction of the piston member may be hindered.

  The present invention has been made in consideration of such circumstances, and can suppress wear of the shaft portion into which the piston member is slidably fitted, and can maintain good sliding of the piston member over a long period of time. An object is to provide a vibration isolator.

  In order to solve the above problems and achieve such an object, the vibration isolator of the present invention includes a cylindrical first mounting member coupled to one of a vibration generating unit and a vibration receiving unit, a vibration A second mounting member connected to the other of the generator and the vibration receiving unit; a rubber elastic body that elastically connects these both mounting members; and the rubber elastic body inside the first mounting member. In the main liquid chamber in which the liquid is sealed as a part of the partition wall and the internal volume changes due to deformation of the rubber elastic body, and in the sub liquid chamber in which at least a part of the partition wall is deformable and in which the liquid is sealed A partition member having a cylindrical shape, and an orifice passage communicating with the main liquid chamber and the sub liquid chamber is formed in the partition member. The orifice passage is more liquid than the shake orifice and the shake orifice. Flow of An idle orifice having a small resistance, and the partition member includes an orifice space that forms a part of the idle orifice and communicates with the secondary liquid chamber, and is isolated from the idle orifice and is connected to the main liquid chamber. A communicating pressure space; a piston member that is partitioned; and a shaft portion that extends along the expansion / contraction direction of each of the orifice space and the pressure space and is slidably fitted to the piston member, The piston member is a vibration isolator that switches between the shake orifice and the idle orifice by sliding in the expansion / contraction direction on the shaft portion in accordance with a fluid pressure fluctuation in the main fluid chamber, and the shaft portion is A shaft body formed integrally with the partition member, and a hard layer provided on the outer periphery of the shaft body and having a hardness higher than that of the material forming the shaft body. And features.

  In this invention, the shaft portion includes a shaft body formed integrally with the partition member, and a hard layer having a hardness higher than that of the material provided on the outer periphery of the shaft body and forming the shaft body. Therefore, the piston member slides on the hard layer along the expansion / contraction direction, and the wear resistance of the shaft portion can be improved as compared with the conventional configuration in which the piston member slides on the shaft body. It becomes possible, and the favorable sliding along the said expansion / contraction direction of a piston member can be maintained over a long period of time.

  Here, the hard layer may contain a lubricant.

  In this case, since the hard layer contains a lubricant, the frictional force generated between the piston member and the shaft portion when the piston member slides as described above can be reduced. Thus, the wear resistance of the shaft portion can be improved more reliably.

  The hard layer may be a pipe fitted to the shaft body.

  In this case, since the hard layer is a pipe, for example, compared with the case where the hard layer is formed by performing chemical treatment or mechanical treatment on the outer peripheral surface of the shaft body formed integrally with the partition member. Thus, the vibration isolator can be easily formed, and an increase in manufacturing cost can be suppressed.

  According to the present invention, it is possible to suppress wear of the shaft portion into which the piston member is slidably fitted, and to maintain good sliding of the piston member over a long period of time.

It is a longitudinal section of a vibration isolator shown as one embodiment concerning the present invention. FIG. 2 is a partially enlarged view of the vibration isolator shown in FIG. 1, showing a state where a short-circuit communication hole is opened and an orifice passage is switched to an idle orifice. FIG. 2 is a partially enlarged view of the vibration isolator shown in FIG. 1, showing a state where a short-circuit communication hole is closed by a piston member and an orifice passage is switched to a shake orifice. It is a disassembled perspective view of the partition member, piston member, and axial part which are shown in FIGS. It is the perspective view which looked at the orifice member shown in FIGS. 1-4 from three directions. It is a partially expanded longitudinal cross-sectional view of the vibration isolator shown as other embodiment which concerns on this invention.

  Hereinafter, an embodiment of a vibration isolator according to the present invention will be described with reference to FIGS. The vibration isolator 10 includes a cylindrical first mounting member 11 connected to one of the vibration generating unit and the vibration receiving unit, and a second mounting connected to the other of the vibration generating unit and the vibration receiving unit. The member 12, the first rubber elastic body 13 that elastically connects the first and second mounting members 11 and 12, and the main liquid chamber 14 and the sub liquid chamber 15 to be described later in the interior of the first mounting member 11. And a partition member 16 partitioned into two.

Each of these members is formed in a circular shape or an annular shape when viewed from above, and is disposed coaxially with the common shaft. Hereinafter, this common axis is referred to as a central axis O.
When the vibration isolator 10 is mounted on, for example, an automobile, the second mounting member 12 is connected to the engine as the vibration generating unit, while the first mounting member 11 is connected to the vehicle body as the vibration receiving unit. As a result, transmission of engine vibration to the vehicle body can be suppressed.

  Here, in the first attachment member 11, a throttle portion 11 a that is recessed toward the inside in the radial direction is formed on the entire circumference in the central axis O direction. In the first mounting member 11, one end opening located on one end side in the central axis O direction with respect to the throttle portion 11 a is closed by the first rubber elastic body 13, and in the central axis O direction from the throttle portion 11 a. The other end opening located on the other end side is closed with a diaphragm 19.

  The diaphragm 19 is formed in a circular shape when viewed from above. Further, the outer peripheral edge of the diaphragm 19 is vulcanized and bonded to the inner peripheral surface of the fitting cylinder 19a over the entire periphery. The fitting cylinder 19 a is fitted into the other end opening of the first mounting member 11, whereby the diaphragm 19 is disposed on the first mounting member 11.

  The second mounting member 12 is formed in a columnar shape, and is disposed at one end opening in the central axis O direction of the first mounting member 11, and the first rubber elastic body 13 is opened at one end of the first mounting member 11. The first mounting member 11 is closed from one end side in the direction of the central axis O by being adhered to the outer peripheral surface of the second mounting member 12.

  In addition, the 1st rubber elastic body 13 is adhere | attached on the whole area of the internal peripheral surface of the one end side part 11b located in the one end side of the said center axis line O direction rather than the aperture | diaphragm | squeeze part 11a in the 1st attachment member 11. An internal thread portion is formed on one end surface of the second mounting member 12. Further, one axial end portion of the second mounting member 12 protrudes outward in the central axis O direction from one end opening surface of the first mounting member 11 in the central axis O direction.

  In the above configuration, a portion of the inside of the first mounting member 11 located between the diaphragm 19 and the first rubber elastic body 13 is liquid-tightly closed by the diaphragm 19 and the first rubber elastic body 13. For example, the liquid chamber is filled with a liquid such as ethylene glycol, water, or silicone oil. The liquid chamber has a first liquid elastic body 13 as a part of a partition wall by a partition member 16 and a main liquid chamber 14 whose inner volume changes due to deformation of the first rubber elastic body 13 and a diaphragm 19. It is divided into a sub-liquid chamber 15 which has a part of the partition wall and whose internal volume changes due to the deformation of the diaphragm 19.

Here, on the inner peripheral surface of the first mounting member 11, the entire region excluding the one end side portion 11 b to which the first rubber elastic body 13 is bonded is covered with the rubber film 18.
Further, in the first attachment member 11, a side opening is formed in the other end portion 11c located on the other end side in the direction of the central axis O with respect to the throttle portion 11a, and this side opening is not shown in the figure. The second rubber elastic body is closed. Further, the first rubber elastic body 13, the rubber film 18 and the second rubber elastic body are integrally formed of the same rubber material whose main component is, for example, natural rubber.

The partition member 16 includes a bottomed cylindrical orifice member 21 disposed so as to open toward one end in the direction of the central axis O, and a disc-shaped valve body 22 that closes the opening of the orifice member 21. And a pressing plate 23 that is fitted to the orifice member 21 and covers the valve body 22 from the main liquid chamber 14 side.
The partition member 16 is formed with an orifice passage 30 that connects the main liquid chamber 14 and the sub liquid chamber 15. The orifice passage 30 has a liquid flow resistance higher than that of the shake orifice 31 and the shake orifice 31. And a small idle orifice 32.

  On the outer peripheral surface of the orifice member 21, there are formed circumferential grooves 21a and 21b extending in a direction inclined with respect to both the circumferential direction and the central axis O direction. The orifice member 21 is fitted in the other end portion 11c of the first mounting member 11, and the circumferential grooves 21a and 21b are formed on the inner peripheral surface of the first mounting member 11 from the outside in the radial direction. It is blocked by the covered rubber film 18.

  Here, as shown in FIG. 4 and FIG. 5, the circumferential grooves 21 a and 21 b have different flow channel cross-sectional areas at intermediate positions in the extending direction, and are the first circumferential grooves located on the main liquid chamber 14 side. 21a and a second circumferential groove 21b that is located on the side of the auxiliary liquid chamber 15 and has a smaller channel cross-sectional area than the first circumferential groove 21a. In the present embodiment, the size of the first circumferential groove 21a in the direction of the central axis O is larger than the size of the second circumferential groove 21b in the direction of the central axis O, and the size in the radial direction, that is, the depth is They are equivalent to each other. The flow passage cross-sectional area of the first circumferential groove 21a is set so as to correspond to the frequency (for example, 18 Hz to 40 Hz) and the amplitude (for example, ± 0.2 mm or less) of idle vibration that occurs during idling operation of the vehicle. . Further, the path length of the first circumferential groove 21a is ½ times or less of the entire length of the circumferential grooves 21a and 21b and is shorter than the path length of the second circumferential groove 21b.

  The outer circumferential surface of the orifice member 21 includes a first communication path 21c extending from an end of the first circumferential groove 21a on the main liquid chamber 14 side to one end of the orifice member 21 in the central axis O direction, and a second circumference. A second communication passage 21g extending from the end portion of the groove 21b on the side of the sub liquid chamber 15 to the other end of the orifice member 21 in the central axis O direction is formed. Note that the first communication passage 21c faces the second rubber elastic body in the radial direction.

  Here, a short-circuit communication hole 24 that opens toward the inside of the orifice member 21 is formed at the end of the bottom surface of the first circumferential groove 21a on the second circumferential groove 21b side (sub liquid chamber 15 side). The front view shape of the short-circuit communication hole 24 is a slot shape that is long in the extending direction of the circumferential grooves 21a and 21b, and the size of the extending direction is the size of the direction orthogonal to the extending direction. It is more than twice. Further, the opening area of the short-circuit communication hole 24 is larger than the flow path cross-sectional area of the second circumferential groove 21b.

  Furthermore, a plurality of flow openings 21e are formed in the bottom wall portion 21d of the orifice member 21 so as to communicate the inside of the orifice member 21 and the auxiliary liquid chamber 15 with an interval in the circumferential direction. Further, in the bottom wall portion 21d, the radial center portion 21f located on the inner side in the radial direction from the flow opening 21e is closer to the auxiliary liquid chamber 15 side than the other portions, as shown in FIGS. It protrudes toward and is thicker.

  A plurality of valve seat openings 23 a are formed on the surface of the holding plate 23 that faces the valve element 22 with an interval in the circumferential direction. Further, a notch portion 23 b is formed in a portion of the pressing plate 23 corresponding to the first communication path 21 c of the orifice member 21. Thus, the first circumferential groove 21a communicates with the main liquid chamber 14 via the first communication passage 21c and the notch 23b.

  The valve body 22 is formed in a disk shape from, for example, a rubber composition such as NR or NBR. The upper surface that contacts the pressing plate 23 is formed in a flat shape, and the lower surface opposite to the upper surface is the diameter of the valve body 22. It is formed in an inclined surface shape that gradually extends toward the main liquid chamber 14 side from the inner side to the outer side in the direction. The upper surface of the valve body 22 is in pressure contact with the lower surface of the pressing plate 23 and closes the valve seat opening 23a. In addition, a plurality of through holes 22a penetrating in the thickness direction are formed in the outer peripheral edge portion of the valve body 22 at intervals in the circumferential direction. Further, the outer peripheral edge in the radial direction of the valve seat opening 23 a of the presser plate 23 is located on the inner side in the radial direction with respect to the inner peripheral edge in the radial direction of the through hole 22 a of the valve body 22.

  And in the valve body 22, the part located in the said radial direction outer side rather than the through-hole 22a is in the state pinched | interposed by the holding | suppressing plate 23 and the orifice member 21, and the part continued in the said radial direction inside the through-hole 22a. The main fluid chamber 14 is bent and deformed by the hydraulic pressure applied through the valve seat opening 23a of the holding plate 23.

  As described above, when the valve body 22 bends toward the sub liquid chamber 15 side as described above due to the hydraulic pressure acting from the main liquid chamber 14 through the valve seat opening 23a of the holding plate 23, the liquid in the main liquid chamber 14 is discharged. On the other hand, the liquid flows through the valve seat opening 23a of the holding plate 23 and the through hole 22a of the valve body 22 into the inside of the orifice member 21 (in a pressurizing space 26 to be described later), while the liquid is opposite to the orifice member 21. Even if it tries to flow into the main liquid chamber 14 from the inside, the valve body 22 is pressed against the holding plate 23 to close the valve seat opening 23a, thereby preventing this flow-in. That is, the valve body 22 is a check valve.

Here, the orifice member 21 (partition member 16) has a piston member 27 that divides the inside into an orifice space 25 on the side of the secondary liquid chamber 15 and a pressure space 26 on the side of the main liquid chamber 14, and the orifice space 25. And a shaft portion 28 extending along the expansion / contraction direction of the pressure space 26 (in the illustrated example, the direction of the central axis O) and having a piston member 27 slidably fitted thereto. The piston member 27 opens and closes the short-circuit communication hole 24 by sliding on the shaft portion 28 in the expansion / contraction direction in accordance with the fluid pressure fluctuation in the main fluid chamber 14.
In the illustrated example, a stopper cylinder 17 formed in a ring shape with a rubber material is fitted to an end of the inner peripheral surface of the orifice member 21 on the bottom wall 21d side. Thus, the end position of the piston member 27 on the main liquid chamber 14 side is determined by the valve body 22, and the end position of the sub liquid chamber 15 side is determined by the stopper cylinder 17.

  The orifice space 25 communicates with the auxiliary liquid chamber 15 via a flow opening 21 e formed in the bottom wall portion 21 d of the orifice member 21. The pressurizing space 26 communicates with the main liquid chamber 14 through a through hole 22 a formed in the valve body 22 and a valve seat opening 23 a formed in the holding plate 23.

  The shaft portion 28 is erected on the bottom wall portion 21 d of the orifice member 21 toward the main liquid chamber 14 side, and the tip surface thereof is in pressure contact with the lower surface of the valve element 22. In the illustrated example, the shaft portion 28 is solid. Further, a coil spring 33 is disposed between the bottom wall portion 21 d and the piston member 27. The coil member 33 urges the piston member 27 toward the main liquid chamber 14 side. This urging force is larger than the force that balances the hydraulic pressure in the pressurizing space 26 when the idle vibration is input, and smaller than the force that balances the hydraulic pressure in the pressurizing space 26 when the shake vibration is input. ing.

  In the above configuration, idle vibration is applied, and as shown in FIG. 2, the valve body 22 closes the valve seat opening 23 a of the holding plate 23, and the piston member 27 is energized by the coil spring 33. When positioned on the 14 side, the short-circuit communication hole 24 is open, and the first circumferential groove 21 a and the orifice space 25 communicate with each other through the short-circuit communication hole 24.

As a result, the liquid that has flowed into the first circumferential groove 21a from the main liquid chamber 14 through the notch portion 23b of the pressing plate 23 and the first communication passage 21c of the orifice member 21 in the first circumferential groove 21a. When it reaches the end on the side of the second circumferential groove 21b, it preferentially flows into the orifice space 25 through the short-circuit communication hole 24 having a smaller flow resistance of the liquid than the second circumferential groove 21b. It passes through and reaches the auxiliary liquid chamber 15. Further, the liquid flowing into the first circumferential groove 21a from the sub liquid chamber 15 through the circulation opening 21e, the orifice space 25, and the short-circuit communication hole 24 of the orifice member 21 has a liquid flow resistance higher than that of the second circumferential groove 21b. It passes through the small first circumferential groove 21a preferentially and reaches the main liquid chamber 14 via the first communication passage 21c of the orifice member 21 and the notch 23b of the pressing plate 23.
That is, the idle orifice 32 that attenuates and absorbs idle vibration includes the notch 23b of the holding plate 23, the first communication path 21c of the orifice member 21, the first circumferential groove 21a, the short-circuit communication hole 24, the orifice space 25, and the flow opening. 21e.

On the other hand, the shake vibration (for example, the frequency is 8 Hz to 17 Hz and the amplitude is larger than ± 0.2 mm) acts, and the valve body 22 bends and deforms as described above to open the valve seat opening 23a of the holding plate 23. When the fluid pressure in the main fluid chamber 14 acts on the pressurizing space 26 through the valve seat opening 23a and the through hole 22a of the valve body 22, the piston member 27 is moved to the shaft portion as shown in FIG. 28 is slid toward the auxiliary liquid chamber 15 to close the short-circuit communication hole 24 formed in the orifice member 21. Thereby, the communication between the first circumferential groove 21a and the orifice space 25 is blocked, and the liquid is notched 23b of the holding plate 23, the first communication path 21c of the orifice member 21, the first circumferential groove 21a, the second circumference. It moves between the main liquid chamber 14 and the sub liquid chamber 15 through the groove 21b and the second communication passage 21g.
That is, the shake orifice 31 that attenuates and absorbs the shake vibration includes the notch 23b of the holding plate 23, the first communication path 21c, the first circumferential groove 21a, the second circumferential groove 21b, and the second communication path 21g of the orifice member 21. It is comprised by.

And in this embodiment, the axial part 28 is provided in the outer peripheral part of the axial part main body 28a integrally formed with the orifice member 21 (partition member 16), and this axial part main body 28a, and forms the said axial part main body 28a. A hard layer 28b having a higher hardness than the material to be manufactured.
When the shaft main body 28a and the orifice member 21 are integrally formed of an aluminum alloy such as ADC12 (JIS H5302) or A5000, the hard layer 28b is hard anodized on the outer peripheral surface of the shaft main body 28a. Anodizing treatment), or metal powder having a particle size of 40 μm to 200 μm is sprayed on the outer peripheral surface of the shaft body 28a at a speed of 100 m / s or more, or an electroless nickel plating treatment is performed. And so on. The hard layer 28b has a hardness of 400 Hv or higher.

Further, when the shaft main body 28a and the orifice member 21 are integrally formed of a synthetic resin such as polyphenyl sulfide (PPS), the hard layer 28b is formed on the outer peripheral surface of the shaft main body 28a, for example, by electroless nickel plating. It is formed by processing.
The piston member 27 fitted to the shaft portion 28 is formed of, for example, a synthetic resin (polyphenyl sulfide (PPS) or polyacetal (POM)).

  Furthermore, in the present embodiment, the hard layer 28b contains a lubricant. For example, when the hard layer 28b is formed by subjecting the outer peripheral surface of the shaft body 28a to a hard anodizing treatment, the outer periphery of the hard layer 28b is subjected to a sealing treatment with a lubricant such as polytetrafluoroethylene or molybdenum disulfide. By filling the minute holes opening on the surface with the lubricant, the hard layer 28b contains the lubricant.

As described above, according to the vibration isolator 10 according to the present embodiment, the shaft portion 28 is integrally formed with the orifice member 21 (partition member 16), and the outer periphery of the shaft portion main body 28a. And a hard layer 28b having a higher hardness than the material forming the shaft body 28a, the piston member 27 slides on the hard layer 28b along the expansion / contraction direction. The wear resistance of the shaft portion 28 can be improved compared to the conventional configuration in which the shaft portion main body 28a is slid, and good sliding along the expansion / contraction direction of the piston member 27 can be performed over a long period of time. Can be maintained.
Further, since the hard layer 28b contains a lubricant, the frictional force generated between the piston member 27 and the shaft portion 28 can be reduced when the piston member 27 slides as described above. As a result, the wear resistance of the shaft portion 28 can be more reliably improved.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, instead of the shaft portion 28 shown in the above embodiment, as shown in FIG. 6, the orifice member 21 and the shaft portion main body are formed on the outer peripheral surface of the shaft portion main body 28 a formed integrally with the orifice member 21. You may employ | adopt the axial part 34 with which the pipe (hard layer) 34b which consists of a material whose hardness is higher than the material which forms 28a was fitted. In other words, the pipe 34b may be employed instead of the hard layer 28b.

The pipe 34b is formed of, for example, tempered S45C or SUS420, or SUS304 or SUS305.
Instead of these materials, the pipe 34b may be formed of an aluminum alloy such as ADC12 or A5000, for example, as in the embodiment shown in FIGS. 1 to 5, or a synthetic resin such as PPS. May be formed. In the former case, similarly to the above embodiment, the outer peripheral surface of the pipe 34b is subjected to a hard anodizing treatment, or a metal powder having a particle diameter of 40 μm to 200 μm is applied to the outer peripheral surface of the pipe 34b at a speed of 100 m / s or more. Spray or electroless nickel plating. Among these, when the hard alumite treatment is performed, it is preferable to perform the sealing treatment on the outer peripheral surface of the pipe 34b using the lubricant as in the above embodiment. In the latter case, for example, electroless nickel plating is performed on the outer peripheral surface of the pipe 34b as in the above embodiment.

  According to the vibration isolator 10 according to the present embodiment, since the pipe 34b is fitted to the outer peripheral surface of the shaft body 28a, the same effect as that of the above-described embodiment shown in FIGS. In addition, for example, compared with the case where the hard layer 28b is formed by performing chemical treatment or mechanical treatment on the outer peripheral surface of the shaft body 28a formed integrally with the orifice member 21 (partition member 16). The vibration isolator 10 can be easily formed, and an increase in manufacturing cost can be suppressed.

Moreover, the form of the partition member 16 is not limited to the above embodiment, and may be changed as appropriate.
Further, the partition member 16 may be provided with a receiving plate that supports the valve element 22 from the auxiliary liquid chamber 15 side. A plurality of communication openings are formed on the surface of the receiving plate facing the valve body 22 at intervals in the circumferential direction, and a through hole 22a of the valve body 22 is formed between both end edges in the radial direction of the communication opening. The inner peripheral edge in the radial direction may be positioned.

  Wear of the shaft portion into which the piston member is slidably fitted can be suppressed, and good sliding of the piston member can be maintained for a long time.

DESCRIPTION OF SYMBOLS 10 Anti-vibration device 11 1st attachment member 12 2nd attachment member 13 Rubber elastic body (1st rubber elastic body)
14 Main liquid chamber 15 Sub liquid chamber 16 Partition member 21 Orifice member 25 Orifice space 26 Pressurizing space 27 Piston member 28, 34 Shaft portion 28a Shaft portion main body 28b, 34b Hard layer 30 Orifice passage 31 Shake orifice 32 Idle orifice

Claims (3)

A cylindrical first attachment member coupled to either one of the vibration generating portion and the vibration receiving portion;
A second attachment member coupled to either the vibration generating portion or the vibration receiving portion;
A rubber elastic body that elastically connects these both mounting members;
A liquid is sealed inside the first mounting member with the rubber elastic body as a part of the partition wall, and a main liquid chamber whose internal volume changes due to deformation of the rubber elastic body, and at least a part of the partition wall can be deformed. A cylindrical partition member that is formed and partitions into a secondary liquid chamber in which a liquid is enclosed,
The partition member is formed with an orifice passage communicating with the main liquid chamber and the sub liquid chamber, and the orifice passage includes a shake orifice and an idle orifice having a liquid flow resistance smaller than that of the shake orifice,
The partition member is divided into an orifice space that forms part of an idle orifice and communicates with the secondary liquid chamber, and a pressurized space that is isolated from the idle orifice and communicates with the main liquid chamber. A piston member that extends along the expansion and contraction directions of each of the orifice space and the pressurizing space, and a shaft portion in which the piston member is slidably fitted.
The piston member is a vibration isolator that switches between the shake orifice and the idle orifice by sliding in the expansion / contraction direction on the shaft portion in accordance with fluid pressure fluctuation in the main fluid chamber,
The shaft portion includes a shaft portion main body formed integrally with the partition member, and a hard layer provided on an outer peripheral portion of the shaft portion main body and having a hardness higher than that of a material forming the shaft portion main body. Anti-vibration device characterized by The vibration isolator according to claim 1,
The vibration isolator according to claim 1, wherein the hard layer contains a lubricant. The vibration isolator according to claim 1 or 2,
The vibration-proof device, wherein the hard layer is a pipe fitted to the shaft body.

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