JP4046203B2 - Liquid enclosed air spring - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid-filled air spring that can absorb vibrations in an arbitrary direction in a three-dimensional space, and can be suitably used particularly as an anti-vibration support for a vehicle engine.
[0002]
[Prior art]
Anti-vibration rubber is known as an anti-vibration support base for automobile engines. Recently, a liquid chamber and an air chamber are placed under the anti-vibration rubber in order to improve the vibration damping function. Came to be used. FIG. 5 shows an example thereof. A partition plate 3, a rubber diaphragm 4 and a dish-shaped receiving plate 5 are fixed in order to the lower end of the vibration isolating rubber 1 via the intermediate cylinder 2, and A first liquid chamber 6A, a second liquid chamber 6B communicating with the first liquid chamber 6A and the orifice 3a on the partition plate 3 below the partition plate 3, and an air chamber 7 below the diaphragm 4 are formed. The top plate 1a fixed to the upper end of the anti-vibration rubber 1 is fixed to the engine (not shown) with bolts 8, and the backing plate 5 is fixed to the vehicle body frame (not shown) with hollow bolts 9. .
[0003]
Then, a hydraulic fluid such as ethylene glycol is sealed in the first liquid chamber 6A and the second liquid chamber 6B, and air is contained in the air chamber 7 or an air pipe connected to the hollow bolt 9 ( When a predetermined pressure of air is supplied from a controlled pressure supply source through a controlled pressure supply source and a vibration load of the engine is applied to the anti-vibration rubber 1, the liquid that fills the first liquid chamber 6A and the second liquid chamber 6B Moves between the liquid chambers 6A and 6B through the orifice 3a, attenuates the vibration by the frictional resistance when passing through the orifice, and absorbs the volume change of the second liquid chamber 6B accompanying this movement in the air chamber 7. It has become.
[0004]
Since the above-described conventional apparatus supports the engine via the vibration isolating rubber 1 on a rigid support base composed of the intermediate cylinder 2 and the backing plate 5, it absorbs vibrations in the vertical direction, the front-rear direction, and the left-right direction. For the vibration in the low frequency region that occurs during idling, the damping coefficient can be increased according to a predetermined frequency by setting the diameter and length of the orifice 3a. In order to reduce the static deflection caused by the support load, it is necessary to increase the spring constant. Especially when a large engine is installed, the above-mentioned spring constant is set large in advance to reduce the static deflection. There was a need. In addition, when the orifice is set to increase the damping force in the low frequency region, the resistance of the orifice is increased with respect to the high frequency vibration generated by the high speed rotation, and the flow of the liquid in the liquid chambers 6A and 6B becomes difficult. The viscous friction is reduced, the damping force is lowered, and the fluid pressure in the fluid chambers 6A and 6B is increased, so that there is a problem that the overall spring constant is further increased.
[0005]
In order to solve the above problem, a valve or other liquid passage is formed around the partition plate 3 or in the vicinity of the orifice 3a in the central portion to reduce the movement resistance of the liquid between the liquid chambers 6A and 6B in the high frequency region. Various attempts have been made, but the basic form as an engine mount is to fix the vibration isolating rubber 1 on a rigid support base composed of the intermediate cylinder 2 and the backing plate 5, so that the engine becomes large. The deflection of the anti-vibration rubber 1 due to a static load increases, and it is inevitable to increase the spring constant to suppress this, and it is difficult to keep the overall spring constant low when the hydraulic pressure increases.
[0006]
[Problems to be solved by the invention]
The present invention eliminates vibration-proof rubber and uses an air spring as a basic form, and by combining a first liquid chamber and a second liquid chamber that communicate with each other, vibration in any direction can be absorbed and the support load can be reduced. Regardless of the spring constant, regardless of the diameter and length of the orifice set according to the frequency, a damping force proportional to the support load can be obtained for both the low frequency range and the high frequency range, The present invention provides a liquid-filled air spring suitable for supporting vibration isolation of an engine.
[0007]
[Means for Solving the Problems]
The liquid-filled air spring according to the present invention includes an air chamber and a liquid chamber that are disposed between two opposing substrates along an axis perpendicular to the substrate and connects the two substrates. One of the substrates is configured to be elastically displaceable in any direction with respect to the other, the air chamber has an air spring function, and the liquid chamber has one of the substrates by a partition plate having an orifice. A liquid-filled air spring having a vibration damping function divided into a first liquid chamber in contact with a second liquid chamber in contact with the air chamber and a side wall of the first liquid chamber having a flexible first diaphragm Is formed in a cylindrical shape connecting the outer periphery of one substrate and the outer periphery of the partition plate having a diameter difference with respect to the outer periphery of the substrate, and the small-diameter side end portion together with the one substrate or the partition plate is the cylindrical portion of the first diaphragm It is pushed inside, and the partition plate The side wall of the second liquid chamber connecting the periphery and the outer periphery of the other substrate is formed in a cylindrical shape with a hard plate, and the outer peripheral edge of the flexible second diaphragm is fixed inside the second liquid chamber. An air chamber is formed between the second diaphragm and the other substrate .
[0008]
In the present invention, the configuration, the side walls of the first liquid chamber, one of the substrates periphery by a first diaphragm of a flexible rubber, such as one of the substrates to be able to elastically displace in any direction relative to the other And a cylindrical plate connecting the outer periphery of the partition plate having a diameter difference with respect to the outer periphery of the substrate, and the small-diameter side end portion is pushed into the cylindrical portion of the first diaphragm together with the one substrate or the partition plate, In addition, the side wall of the second liquid chamber connecting the outer periphery of the partition plate and the outer periphery of the other substrate is formed in a cylindrical shape with a hard plate such as a metal, and a flexible material made of rubber or resin is formed inside the second liquid chamber. It is obtained by fixing the outer periphery of the sex second diaphragm. In this case, the air chamber mainly compresses and expands due to the axial displacement perpendicular to the substrates, and the first diaphragm is deformed so as to be mainly crushed by the parallel displacement between the substrates. It is easy to fix the second diaphragm that absorbs the parallel displacement and constitutes the first diaphragm and the air chamber.
[0009]
As described above, the side wall of the first liquid chamber is formed in a cylindrical shape connecting the outer periphery of one substrate and the outer periphery of the partition plate having a diameter difference with respect to the outer periphery of the substrate by a flexible first diaphragm such as rubber. When the small diameter side end portion is pushed into the cylindrical portion of the first diaphragm together with the one substrate or the partition plate, the first liquid is placed on the outer periphery of the one substrate and the partition plate having the larger diameter. An outer cylinder in contact with the outer surface of the side wall of the chamber can be projected. In this case, a reaction force is generated against the parallel displacement between the substrates, and this acts as a spring against the parallel displacement, and its rigidity is the first liquid. Since it is proportional to the pressure in the chamber, the spring constant of the parallel displacement can be easily set by the support load.
[0010]
The above liquid-enclosed air spring has one board connected to the vehicle frame side and the other to the engine side with bolts or the like, and the air chamber is filled with any pressure gas that can be used economically, for example, air. It is used as an engine mount while maintaining a predetermined pressure. In this case, either the first liquid chamber or the air chamber may be directed to the engine side. When the first liquid chamber is directed to the engine side, the engine load is applied to the air chamber via the one substrate, the first liquid chamber, and the second liquid chamber. Further, when the air chamber is directed to the engine side, the engine load is immediately applied to the air chamber via the other substrate, and this air chamber is supported from below through the second liquid chamber and the first liquid chamber. . In any case, since the elastic constant of the liquid is remarkably larger than that of the gas, the liquid is hardly compressed and the gas is compressed to support the engine at an arbitrary height.
[0011]
The support height of the engine is arbitrarily set by the gas pressure. Further, the spring constant as the air spring is arbitrarily set by the pressure and volume of the gas, and is not affected by the size of the engine, that is, the deflection due to the static load. In addition, since the product of the gas pressure and the pressure receiving area becomes the support load, it can be used as a mount for a large diesel engine mounted on a large bus or truck by setting the gas pressure large.
[0012]
When the engine is driven, the vibration is absorbed by the gas. In addition, since the spring constant can be set low regardless of the magnitude of the static load, it is possible to prevent vibration from being transmitted to the frame even when a large engine is installed or during running as well as during idling. Since the first liquid chamber and the second liquid chamber are connected by an orifice, when one of the first liquid chamber and the second liquid chamber is pressurized, the pressure difference generated between the two chambers causes a difference between the two chambers. The liquid moves through the orifice, and the vibration is attenuated by the resistance at that time. This orifice may be formed by simply making a hole in the partition plate, but it may be formed by attaching a cylinder to the partition plate, and the peak value and peak frequency of the damping force are arbitrarily set according to the diameter and length of this orifice. be able to.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1
In FIG. 1, reference numeral 11 denotes a circular upper substrate. A mounting bolt 12 projects upward at the center, and a diaphragm (first diaphragm) 13 formed into a cylindrical shape with rubber containing reinforcing fibers on its outer peripheral edge 11a. The bead portion 13a and the upper end of the metal outer cylinder 14 are caulked and the outer cylinder 14 is in contact with the outer surface of the diaphragm 13. The other end bead portion 13 b of the diaphragm 13 is caulked to the upper end edge portion 15 a of the inner cylinder 15 having a smaller diameter than the outer cylinder 14, and the inner cylinder 15 is formed in a piston shape inside the upper cylindrical portion of the diaphragm 13. By pushing, the lower half of the diaphragm 13 is bent into a U-shaped cross section as shown. The outer periphery of a partition plate 16 having a disc shape and a circular hole-shaped orifice 16a is fixed to the inner surface of the upper end edge portion 15a of the inner cylinder 15, and the upper surface of the outer periphery of the partition plate 16 is made of rubber. The ring-shaped stopper 17 is fixed.
[0014]
The outer cylinder 14 and the inner cylinder 15 extend below the curved portion 13 c of the diaphragm 13, and a rubber ring-shaped stopper 18 is fixed to the outer surface on the lower end side of the inner cylinder 15. The surface faces the inner surface of the lower end portion of the outer cylinder 14. The outer peripheral portion of the flexible second diaphragm 19 made of rubber or synthetic resin and the outer peripheral portion of the dish-shaped lower substrate 20 are caulked with the lower substrate 20 facing down inside the lower end edge portion 15b of the inner cylinder 15. The hollow bolt 21 protrudes downward from the center of the lower substrate 20. The hollow bolt 21 fixes the lower substrate 20 to a vehicle body frame (not shown) of a vehicle, and the tip thereof is connected to a controlled pressure supply source via an air pipe (not shown). The
[0015]
In a space surrounded by the upper substrate 11, the diaphragm 13 and the second diaphragm 19, an arbitrary liquid of a predetermined pressure, for example, ethylene glycol, is sealed, and the first liquid chamber A is separated above the partition plate 16. Second liquid chambers B are respectively formed below the plate 16. Further, in the space surrounded by the second diaphragm 19 and the lower substrate 20, pressurized air is introduced from the pressure supply source through the center hole of the hollow bolt 21, and an air chamber C having a predetermined pressure is formed. Then, the upper substrate 11 is fixed to the engine with the central mounting bolt 12, and the lower substrate 20 is fixed to the vehicle body frame with the hollow bolt 21.
[0016]
In the above structure, the static load generated by mounting the engine pressurizes the gas in the air chamber C using the liquid that fills the upper substrate 11 and the liquid chambers A and B as a transmission medium, and the upper substrate 11 has a gas pressure and a pressure receiving area. Is supported at a predetermined height. The vertical component of the vibration generated by driving the engine is transmitted to the pressurized gas via the liquid because the elastic constant of the liquid filling the liquid chambers A and B is significantly larger than that of the pressurized gas in the air chamber C. The liquid is absorbed mainly by the elastic deformation of the pressurized gas, and the above-mentioned liquid attenuates the vibration by the frictional resistance when moving between the liquid chambers A and B through the orifice 16a. In the first embodiment, since the ring-shaped stopper 17 is present on the upper surface of the partition plate 16, it is possible to prevent the upper substrate 11 from coming into contact with the upper edge 15a of the inner cylinder 15 due to the abnormal lowering.
[0017]
On the other hand, the horizontal component deforms the diaphragm 13, and the liquid moves between the liquid chambers A and B through the orifice 16a along with the deformation, and transmits vibration to the air chamber C. Therefore, the horizontal component is the diaphragm. 13 is absorbed by the joint action of the elastic deformation 13 and the elastic deformation of the air chamber C, and is attenuated by the passage resistance of the liquid in the orifice 16a. In the first embodiment, since the outer cylinder 14 is in contact with the outer surface of the diaphragm 13, the resistance against deformation of the diaphragm 13 increases in proportion to the liquid pressure. Further, since the ring-shaped stopper 18 is fixed near the lower end of the inner cylinder 15, it is possible to prevent a part of the diaphragm 13 from being crushed by the action of the horizontal component described above.
[0018]
Embodiment 2
In FIG. 2, the upper substrate 11, the mounting bolt 12, the diaphragm (first diaphragm) 13, the outer cylinder 14, the inner cylinder 15, the partition plate 16, the lower substrate 20 and the hollow bolt 21 are configured in the same manner as in the first embodiment. However, in the second embodiment, the second diaphragm 19 </ b> A is formed in a bellows shape with one end closed, and the opening is fixed to the upper edge of the inner cylinder 15. In addition, the orifice 16b is formed in a pipe shape and is fixed to the center of the partition plate 16 so as to face in the vertical direction. Note that the ring-shaped stoppers 17 and 18 of the first embodiment are omitted. In the second embodiment, since the second diaphragm 19A is formed in a bellows shape, it can be applied to a configuration in which the inner cylinder 15 is elongated.
[0019]
Embodiment 3
In the third embodiment shown in FIG. 3, a hollow bolt 21 protrudes upward in the center of the upper substrate 11, one end of the upper cylinder 22 is connected to the outer peripheral edge, and the upper cylinder 22 and the upper substrate 11 face downward. A box is formed. The second diaphragm 19 of the first embodiment, the edges of the partition plate 16 and the upper ends of the outer cylinder 14 and the diaphragm (first diaphragm) 13 are fixed to the lower end of the upper cylinder 22, respectively. The orifice 16b of the second embodiment is fixed. A hollow piston 23 having a diameter smaller than that of the partition plate 16 is disposed below the partition plate 16. The lower end of the diaphragm 13 is connected to the upper end of the hollow piston 23, and the hollow piston 23 is pushed into the diaphragm (first diaphragm). The lower half of (1 diaphragm) 13 is bent into a U-shaped cross section. A mounting bolt 12 projects downward from the center of the lower end of the piston 23.
[0020]
In the third embodiment, the upper substrate 11 is fixed to the engine with the hollow bolt 21, and the air chamber C is formed between the upper substrate 11 and the second diaphragm 19, and is used as a pressure supply source via the hollow bolt 21 and the air pipe. Connected. Further, the space between the second diaphragm 19 and the partition plate 16 constitutes the second liquid chamber B, and the space below the partition plate 16 constitutes the first liquid chamber A. The piston 23 at the lower end is fixed to the vehicle body frame (not shown) with the mounting bolt 12.
[0021]
In this case, the height of the upper substrate 11, that is, the mounting height of the engine tends to be higher than in the first and second embodiments, but the air chamber C and the second liquid chamber B are located above the first liquid chamber A. Therefore, the diameter and volume of the air chamber C can be increased.
[0022]
Embodiment 4
In the fourth embodiment shown in FIG. 4, except that the second diaphragm 19 of the third embodiment is fixed to the outer peripheral edge of the upper substrate 11, the other upper substrate 11, the hollow bolt 21, the upper cylinder 22, the partition plate 16, the orifice 16b, the outer cylinder 14, the diaphragm 13, the hollow piston 23, and the mounting bolt 12 are provided in the same manner as in the third embodiment, and have the same functions as in the third embodiment except that the assembly order can be selected.
[0023]
【The invention's effect】
As described above, according to the present invention, one board can be connected to the frame side of the vehicle and the other to the engine side with bolts or the like, and the gas chamber can be filled with pressure gas and used as an engine mount. In this case, the support height of the engine and the spring constant as an air spring can be arbitrarily set by the gas pressure, and it is not affected by the size of the engine. It can be used as a mount for a large diesel engine mounted on a truck or the like. And since it acts as an air spring with a small spring constant, it is possible to prevent vibrations from being transmitted to the frame not only when idling but also during running, and it has an excellent vibration damping function. Moreover, the attachment control of the 1st diaphragm which comprises the side wall of a 1st liquid chamber, and the 2nd diaphragm which comprises an air chamber is easy.
[0024]
In particular, the invention according to claim 2 increases the resistance force against the parallel displacement between the two substrates, the rigidity of the first liquid chamber becomes proportional to the internal pressure, and the design becomes easy.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a first embodiment.
FIG. 2 is a schematic longitudinal sectional view of a second embodiment.
FIG. 3 is a schematic longitudinal sectional view of a third embodiment.
FIG. 4 is a schematic cross-sectional view of a fourth embodiment.
FIG. 5 is a longitudinal sectional view of a conventional device.
[Explanation of symbols]
11: Upper substrate 12: Mounting bolt 13: First diaphragm (diaphragm) 14: Outer cylinder 15: Inner cylinder 16: Partition plate 16a, 16b: Orifice 17, 18: Ring-shaped stopper 19, 19A: Second diaphragm 20: Lower Substrate 21: Hollow bolt 22: Upper cylinder 23: Hollow piston A: First liquid chamber B: Second liquid chamber C: Air chamber

Claims (2)

An air chamber and a liquid chamber are arranged between two opposing substrates along an axis perpendicular to the substrate and connect the two substrates, and one of the two substrates is optional with respect to the other The air chamber has an air spring function, and the liquid chamber has a first liquid chamber in contact with one of the substrates by a partition plate having an orifice, and the air chamber. In a liquid-filled air spring that is divided into a second liquid chamber that is in contact and has a vibration damping function, the side wall of the first liquid chamber is separated from one substrate outer periphery and the substrate outer periphery by a flexible first diaphragm. The cylindrical plate is connected to the outer periphery of the partition plate having a diameter difference, and the small-diameter side end thereof is pushed into the cylindrical portion of the first diaphragm together with the one substrate or the partition plate. Connect the outer periphery and the outer periphery of the other substrate The side wall of the liquid chamber is formed of a hard plate in a cylindrical shape, and the outer peripheral edge of the flexible second diaphragm is fixed inside the second liquid chamber, so that the space between the second diaphragm and the other substrate is fixed. A liquid-sealed air spring characterized in that an air chamber is formed . 2. The liquid-filled air spring according to claim 1, wherein an outer cylinder that is in contact with the outer surface of the side wall of the first liquid chamber protrudes from the outer periphery of the larger diameter of the one substrate and the partition plate .

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