JP5175530B2 - Vibration isolator - Google Patents

Description

  The present invention relates to an engine mount used when an engine is mounted on a vehicle body, and intends to absorb vibration from the engine and effectively reduce transmission of vibration to the vehicle body side.

  In a vehicle such as a passenger car, an engine as a drive source is attached to the vehicle body via an engine mount, and vibrations from the engine are absorbed by the engine mount and the vibration transmitted to the vehicle body is minimized. I am doing so.

As vibration transmitted from the engine to the vehicle body, vibration transmitted when the vehicle is traveling at a predetermined speed or more (vibration with a low frequency (about 9 to 15 Hz) and large amplitude (shake vibration)), Vibration that is transmitted when the vehicle is idling (frequency (about 18-30Hz) is relatively high compared to shake vibration and vibration with low amplitude (idle vibration)). A hydraulic switch mount is applied to the inside of the casing forming the member, and an orifice having a plurality of types of paths is incorporated together with the working fluid, and the path is selectively switched according to the type of vibration input (for example, (See Patent Document 1).
JP 2007-71313 A

  The vibration isolator described above is intended to absorb and reduce vibrations by utilizing the resonance phenomenon (liquid injection resonance) caused by the liquid confined in the casing. Piston (orifice) that is set (tuned) to the flow resistance corresponding to the frequency and amplitude of the cylinder and that operates with the pressure fluctuation (volume change resulting from vibration) in the casing (main liquid chamber) as the driving force. Of the structural member).

  By the way, this type of engine mount is connected to the main liquid chamber through a passage formed by cutting out the outer wall of the cylinder through a flow path for moving working fluid back and forth. Since it is inevitable to form locally, a gap is likely to form between the component (the holder for holding the check valve) and the working fluid leaks through the gap. In some cases, the vibration absorption and reduction characteristics are reduced.

  An object of the present invention is to propose a vibration isolator capable of reliably absorbing and reducing vibration transmitted from an engine while avoiding the above-described liquid leakage that affects liquid column resonance.

The present invention includes a rubber elastic member and the connecting piece which governs the connection between the vibration generating source embedded fixed, without the body portion of the engine mount, a casing which is integrally connected to the rubber elastic member on one open end, the casing A diaphragm that is disposed at the other open end of the casing and forms a sealed space inside the casing by surrounding the inner wall of the casing and the tip wall surface of the rubber elastic member, and a main liquid chamber is left in the sealed space. And an orifice to be
The orifice is fixedly held on the inner peripheral wall of the casing, and a cylinder that forms a secondary liquid chamber inside the diaphragm with a diaphragm as a partition, and a liquid that is provided in the outer wall of the cylinder and that fills a gap portion of the sealed space is mainly used. A plurality of passages that move back and forth between the liquid chamber and the sub liquid chamber, a plurality of openings connected to the main liquid chamber, a partition lid that fits the tip of the cylinder, and only inflow of liquid from the main liquid chamber has a check valve that allows the holder to fix hold the check valve is sandwiched between each other of the cylinder tip portion and the partition cover the flange portion, reciprocably elastically at the said cylinder A piston that is supported and can be switched to a shake mode or an idle mode by selecting a passage by a forward movement or a backward movement accompanying a fluctuation in the hydraulic pressure of the main liquid chamber,
In the vibration isolator, sealing members for preventing liquid leakage are arranged above and below the flange portion of the holder, respectively.

In the vibration isolator having the above-described configuration, it is desirable to apply a rubber sheet disposed in a pressurized state (press-fit) as the seal member. Further, the holder over has an annular wall which is press-fitted into the inner peripheral wall of the cylinder, one end of the annular wall may be integrally connected to an end portion of the inner peripheral side of the flange portion.

  A liquid leakage prevention seal member is arranged on the upper and lower surfaces of the flange portion of the holder, and the seal member is sandwiched between the upper end surface of the cylinder and the partition lid, thereby reliably avoiding liquid leakage from that portion. be able to.

  By providing the holder with an annular wall that can be press-fitted into the inner peripheral wall of the cylinder, the contact area between the holder and the cylinder is expanded, and higher sealing is possible.

Hereinafter, the present invention will be described more specifically with reference to the drawings.
FIG. 1 is a cross-sectional view of an embodiment of a vibration isolator according to the present invention. FIG. 2 is a diagram showing the appearance of the orifice in an exploded state, and FIGS. 3 (a) and 3 ( b ) are diagrams showing the appearance of the cylinder constituting the orifice with respect to two surfaces.

  Reference numeral 1 in FIG. 1 denotes a ring-shaped rubber elastic member having a curved outer surface having the smallest upper end diameter and gradually increasing the diameter toward the lower end. In this rubber elastic member 1, a metal connecting piece 1a having a substantially frustoconical appearance that tapers toward the lower end is embedded and fixed along the axis L, and a screw hole at the upper end thereof. It is connected to the engine side by screwing a fastening member (bolt or the like) into n via a bracket stay or the like.

  Reference numeral 2 denotes a cylindrical casing that forms the main part of the engine mount. The casing 2 is integrally connected to the lower part of the rubber elastic member 1 at one open end (upper open end), and the casing 2 itself is connected to a holder (not shown) such as a cup. To be connected to the vehicle body side.

  Reference numeral 3 denotes a diaphragm disposed at the other open end (lower open end) of the casing 2 by caulking or the like. The diaphragm 3 is made of a thin disc-shaped rubber material, and an outer peripheral edge portion thereof is vulcanized and bonded to the inner surface of the support ring 3a over the entire circumference. 4 is a rubber coating layer provided on the inner peripheral surface of the casing 2 and integrally connected to the rubber elastic member 1.

  Inside the casing 2, a sealed space surrounded by the diaphragm 3, the rubber elastic member 1 (tip wall surface) and the rubber coating layer 4 is defined.

Furthermore, 5 an orifice disposed leaving a main liquid chamber M ₁ in the closed space. The orifice 5 is fixed and held through the rubber coating layer 4 on the inner wall of the casing 2, a cylinder 5a (cylinders 5a to form the auxiliary liquid chamber M ₂ on the inside of the diaphragm 3 as a partition wall is a diaphragm portion 2a of the casing 2 Between the ring 3a arranged at the lower open end) and a liquid such as water or ethylene glycol which is provided on the outer wall of the cylinder 5a and is filled in the space of the sealed space. includes a plurality of passages 5b for back and forth between each other in the main fluid chamber M ₁ and the auxiliary liquid chamber M _2, a plurality of apertures h leading to the main fluid chamber M _1, the partition cover 5c which fits into the distal end portion of the cylinder 5a If this is arranged adjacent to the partition cover 5c, and a check valve 5d for allowing only the inflow of the liquid from the main liquid chamber M ₁ (composed bending at deformable elastic body by pressure.) this Holder 5e holding check valve 5d and cylinder It is reciprocably elastically supported at the 5a, to allow switching of the selection passageway 5b to appropriately perform shake mode or idle mode by forward or backward movement caused by hydraulic pressure fluctuations in the main liquid chamber M ₁ piston 5f It is made up of.

The above holder. 5e, bottom wall portion 5e ₁ having a plurality of through holes h1 connected to the distal end surface of the piston 5f _(see FIG. 2), adapted to the inner peripheral wall of the integral connecting to cylinders 5a to the bottom wall portion 5e ₁ ( The annular wall 5e ₂ (see FIG. 1) to be fitted by press-fitting is connected to the upper end of the annular wall 5e ₂ and is sandwiched between the tip of the cylinder 5a and the partition lid 5c. It is composed of the flange portion 5e _3.

Further, the piston 5f from the body portion 5f ₁ disc-shaped partitioning its internal space into front space N ₁ and the rear space N ₂ in the cylinder 5a, of the integral connection to the cylinder 5a to the edge of the body portion 5f ₁ is constituted by an annular wall 5f ₂ disposed adjacent to leave a very small gap in the peripheral wall, the through-hole i the body portion 5f ₁ to permit the flow of lead liquid into the front space N ₁ and the rear space N ₂ is formed Has been.

The internal volume of the main liquid chamber M ₁ expands and contracts with the elastic deformation of the rubber elastic member 1, and the diaphragm 3 is displaced by a sufficiently small hydraulic pressure (load). The sub liquid chamber is displaced according to the displacement of the diaphragm 3. the internal volume of the M ₂ is expanded and contracted.

Further, 6a, 6b is the sealing member for arranged liquid leakage prevention in vertically pressed-in condition of the flange portion 5e ₃ of the holder 5e (pressurized). The sealing members 6a and 6b are made of a soft material such as a rubber sheet.

A spring 7 elastically supports the piston 5f. This spring 7 urges the piston 5f so that it is always located at the top dead center (position closest to the check valve 5d), and the urging force is the forward space N ₁ when shake vibration is input. small liquid than the value corresponding to the pressure, is set to a larger spring constant than the value corresponding to the hydraulic pressure in the front space N ₁ when idle vibration is input.

8 is a rod disposed along the axis L between the check valve 5d up to the bottom wall boss 5a ₁ of the cylinder 5a. The rod 8 is slidably fitted into a through hole provided at the center of the piston 5f, and guides the piston 5e when the piston 5f reciprocates between a top dead center and a bottom dead center.

The passage 5b of the orifice 5 is a groove provided in a spiral shape along the outer peripheral wall of the cylinder 5a (circular slightly less than two rounds around the cylinder 5a, and the case where the groove depth is the same is displayed. is.) Thus those formed is shown as an example, the groove width W is relatively wide groove 5b ₁ as shown in FIG. 3 (a) (b), leads to the groove 5b _1, groove 5b the groove 5b ₂ is smaller cross-sectional area narrower groove width W ₁ than _1, consisting of an opening 5b ₃ to penetrate through the groove bottom in the vicinity of the boundary of the groove 5b ₁ and the groove 5b ₂ to the inside of the cylinder 5a. And one end of the passage 5b is opened in the main liquid chamber M ₁ through notch provided in the outer wall and the partition cover 5c of the cylinder 5b K _1, K _{2 (see} FIGS. 2 and 3), the other end of the cylinder 5b It is opened respectively through cutout portions K ₃ provided in the lower portion sub liquid chamber M _2.

Here, the cross-sectional area of the groove 5b ₁ is set to a flow resistance corresponding to the frequency (for example, 18 to 30 Hz) and amplitude of the idle vibration, and the groove 5b ₂ includes the groove 5b ₁ and the whole thereof is shake vibration ( For example, the cross-sectional area is set such that the flow resistance corresponds to 9 to 15 Hz (flow resistance is groove 5b ₁ <groove 5b ₁ + 5b ₂ ). Further, it is assumed that the opening 5b ₃ has an opening area larger than the cross-sectional area of the groove 5b ₁ as a long hole shape along each groove.

Vibration reduction as constituted above device, when shake vibration is input, the rubber elastic member 1 is elastically deformed, a which the main liquid chamber M ₁ in the liquid pressure change occurs pressure increases with (cyclic increased) by toward the main fluid chamber M ₁ in the front space N ₁ of the cylinder 5a flows liquid through the check valve 5d, so that the pressure in the same manner as the front space N ₁ within even the main liquid chamber M ₁ rises .

Since the biasing force of the spring 7 to the piston 5f elastically supporting is also set to a smaller spring constant than the value corresponding to the hydraulic pressure (equilibrium pressure) of the front space N ₁ when the shake vibration is inputted, the front space N The pressure of ₁ causes the piston 5f to slide toward the lower end of the cylinder 5a against the urging force of the spring 7, and maintain the posture shown in FIG. 4 (located at the bottom dead center of the cylinder 5a). The

This state is a state in which the mode is switched to the shake mode, the opening 5b ₃ is closed by the annular peripheral wall 5e ₂ of the piston 5e, and the liquid passes through the grooves 5b ₁ and 5b ₂ of the passage 5 and the main liquid chamber M ₁ and the auxiliary liquid chamber M. _The vibration is quickly absorbed and reduced by the liquid injection resonance when passing through this passage.

In the above engine mount, like the shake vibration if the idle vibration is input, the rubber elastic member 1 is elastically deformed, whereby the fluid pressure of this main fluid chamber M hydraulic pressure change in ₁ with the occurs rise toward the main fluid chamber M ₁ through the check valve 5d forward space N ₁ of the cylinder 5a is liquid by (periodic) flows. At this time, so that the fluid pressure likewise pressure to the main fluid chamber M ₁ in the front space N ₁ increases, the front space N ₁ when the spring 7 the piston 5f elastically supporting the idle vibration is inputted Since the spring constant is set to a value larger than the value corresponding to the hydraulic pressure (equilibrium pressure), when the piston 5f is in the state shown in FIG. 1 (when the piston 5e is at the top dead center) When the state is maintained as it is and the piston 5f is at the bottom dead center as shown in FIG. 4, it is slid from the bottom dead center to the top dead center by the biasing force of the spring 7, thereby opening 5b ₃ of the passage 5b. Is released and switches to idle mode.

Since the flow resistance of the opening 5b _{3 of the} passage 5b is set smaller than that of the groove 5b ₂ , the liquid preferentially passes from the passage 5b ₁ through the opening 5b ₃ to the main liquid chamber M ₁ , when switched to the idle mode. and forth sub-liquid chamber M _2, idle vibration by the liquid Note resonance at that time rapidly absorbed, is reduced.

Vibration damping device according to the present invention, the seal member 6a and below the flange portion 5e ₃ of the holder 5e, 6b are arranged in a pressurized state, the contact at the tip portion of the cylinder 5a by the notch portion K _1, K ₂ Even if the area is locally reduced, reliable sealing is possible at the site, and the effect of absorbing and reducing vibration due to liquid leakage is not reduced.

  In addition, the engine mount according to the present invention operates the piston 5f using a change in hydraulic pressure as a driving force, so that no control means using an electromagnetic solenoid, a pneumatic solenoid, or the like is necessary, and the control means is unnecessary. There is an advantage that the engine mount itself can be downsized.

  In the present invention, absorption and reduction of vibration are mainly performed by liquid injection resonance, but in actuality, vibration is also absorbed and reduced by viscous resistance and pressure loss when the liquid passes through the passage 5b. The

  It is possible to provide a vibration isolator capable of reliably avoiding liquid leakage that has conventionally occurred at the upper end of the piston.

It is the figure which showed typically the embodiment of the vibration isolator according to this invention about the cross section. It is the external appearance perspective view which showed the orifice in the decomposition | disassembly state. It is the figure which showed the external appearance shape of the cylinder about 2 surfaces. FIG. 2 is a view showing an operating state of a piston for the engine mount shown in FIG.

Explanation of symbols

1 Rubber elastic member
1a Connecting piece
2 Casing
2a Aperture
3 Diaphragm
4 Rubber coating layer
5 Orifice
5a cylinder
5b passage
5c Partition lid
5d check valve
5e holder
5f piston
6a, 6b Seal member
7 Spring
8 Rod
n Screw hole
h ₁ through hole
N ₁ front space
N ₂ rear space
M ₁ main liquid chamber
M _{2 secondary} liquid chamber

Claims (3)

A rubber elastic member and the connecting piece which governs the connection between the vibration generating source embedded fixed, without the body portion of the engine mount, a casing which is integrally connected to the rubber elastic member on one open end, the other opening of the casing A diaphragm which is disposed at the end and forms a sealed space inside the casing by surrounding with the inner peripheral wall surface of the casing and the front end wall surface of the rubber elastic member; and an orifice which is disposed leaving the main liquid chamber in the sealed space With
The orifice is fixedly held on the inner peripheral wall of the casing, and a cylinder that forms a secondary liquid chamber inside the diaphragm with a diaphragm as a partition, and a liquid that is provided in the outer wall of the cylinder and that fills a gap portion of the sealed space is mainly used. A plurality of passages that move back and forth between the liquid chamber and the sub liquid chamber, a plurality of openings connected to the main liquid chamber, a partition lid that fits the tip of the cylinder, and only inflow of liquid from the main liquid chamber It has a valve that allows a holder for fixing and holding the check valve is hold the flange portion between each other the cylinder tip portion and the partition cover is reciprocably elastically supported by the said cylinder And a piston that selects the passage by forward or backward movement accompanying the fluctuation of the hydraulic pressure in the main liquid chamber and enables switching to the shake mode or the idle mode.
An anti-vibration device according to claim 1, wherein sealing members for preventing liquid leakage are arranged above and below the flange portion of the holder.   2. The vibration isolator according to claim 1, wherein the seal member is made of a rubber sheet disposed in a pressurized state. 3. The holder according to claim 1, wherein the holder has an annular wall that is press-fitted into an inner peripheral wall of the cylinder, and one end portion of the annular wall is integrally connected to an end portion on the inner peripheral side of the flange portion. Anti-vibration device.

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