JP2881544B2 - Air spring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air spring device and, more particularly, to a vehicle using a pressure difference to determine the position of a lower tank provided below a diaphragm chamber and a piston in a cylinder provided at the center of the lower tank. By changing between the case of vibration and the case of low frequency vibration, the spring constant can be automatically changed, so that it is hard on rough roads and soft on comfortable roads Accordingly, the present invention relates to an air spring device having a very simple structure in which a comfortable ride comfort and good steering stability can always be obtained, and there is no need to perform complicated and expensive electronic control.

[0002]

2. Description of the Related Art Conventionally, air spring devices that provide a soft ride are employed in vehicles such as sightseeing buses, long-distance buses, some large trucks, and luxury passenger cars.
With a simple structure, the volume of the expandable and contractible diaphragm of the air spring device is constant, and it is impossible to change the spring constant according to the road surface condition.

For this reason, if the design is made with emphasis on the riding comfort on a rough road, the spring constant on a good road is too small and the vehicle shakes too much, so that a comfortable riding comfort and good steering stability cannot be obtained. On the other hand, if the design is made with emphasis on the riding comfort on good roads, the spring constant on bad roads is too large, giving rise to a feeling of stiffness, making it impossible to obtain a comfortable riding comfort.

[0004] On the other hand, in order to solve such a drawback, some high-grade air spring devices have an auxiliary tank having a specific volume outside the diaphragm, and a solenoid valve is provided between the auxiliary tank and the diaphragm. The solenoid valve is arranged and controlled by a computer to open and close. When a soft ride is desired (at the time of high-frequency vibration of the vehicle), the solenoid valve is opened and the diaphragm chamber communicates with the auxiliary tank chamber as an air spring. When a hard ride is desired (during low frequency vibration of the vehicle), the solenoid valve is closed to cut off the communication between the diaphragm chamber and the auxiliary tank chamber to reduce the volume as an air spring. Such an air spring device has been put to practical use.

[0005] However, such a high-end air spring device with electronic control requires many expensive components such as various sensors, microcomputers, solenoid valves, and actuators, and has a disadvantage that the cost is high. In particular, there is a problem that it can be used only for high-end models.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to eliminate the above-mentioned drawbacks of the prior art, and has as its object the purpose of the present invention is to provide an expandable and contractible diaphragm and a diaphragm fixed to a lower portion of the diaphragm. A lower tank having a lower tank chamber having a volume smaller than the volume of the diaphragm chamber of the diaphragm; a hollow cylinder integrally provided in the center of the lower tank and communicating with the diaphragm chamber and the lower tank chamber; and a cylinder chamber of the cylinder. The diaphragm chamber and the lower tank chamber are communicated with each other depending on the sliding position, or the communication is shut off. A piston, and a spring for pressing and supporting the piston upward from a bottom plate integrated with the cylinder, and supporting the piston. A pressure chamber communicating with the cylinder chamber is formed between the ton and the bottom plate of the cylinder by an orifice, and the difference between the pressure in the pressure chamber and the pressure in the cylinder chamber causes the piston to generate a low-frequency vibration and a high-frequency vibration. By changing the vertical position to connect or disconnect the diaphragm chamber and the lower tank chamber to change the spring constant, the air spring is used when a hard riding comfort is required such as when driving on a good road. The volume as an air spring is automatically increased and the spring constant is reduced when a soft ride is required, such as when driving on rough roads. And this also allows the solenoid valve,
By obtaining an excellent air spring device that can automatically change the spring constant by detecting the state of vibration from the vehicle with an inexpensive configuration without using expensive components such as various sensors and computers. is there.

It is another object of the present invention to provide a first cylinder communicating with a diaphragm chamber above a cylinder provided at the center of a lower tank.
A second communication hole communicating with the lower tank chamber and a third communication hole communicating with the diaphragm chamber adjacent to the second communication hole at a lower portion of the cylinder; The piston is slidably housed in the outer peripheral portion of the piston. The communication groove extends through the second communication hole and the third communication hole and communicates with the second communication hole and the third communication hole. With the effect of the orifice, the presence or absence of a pressure difference between the cylinder chamber on the upper side of the piston and the pressure chamber on the lower side of the piston is detected, the sliding position of the piston is determined, and the second communication hole and The third communication hole is automatically opened and closed, and the diaphragm chamber and the lower tank chamber are communicated with each other or the communication is cut off, so that the high frequency vibration and the low frequency vibration from the road surface can be reliably reduced by an extremely simple configuration. If you identify Is be to be able to constant automatically changed and thereby is to be always comfortable ride and good steering stability can be obtained in any road conditions.

[0008]

In short, the present invention (claim 1) comprises a telescopic diaphragm, and a lower tank chamber fixed to a lower portion of the diaphragm and having a volume smaller than the volume of the diaphragm chamber of the diaphragm. A lower tank, a hollow cylinder integrally provided at a central portion of the lower tank and communicating with the diaphragm chamber and the lower tank chamber, and slidably housed in the cylinder chamber of the cylinder, penetrating in a plate thickness direction, and passing air. A piston having an orifice having a very large flow path resistance and configured to communicate or interrupt the communication between the diaphragm chamber and the lower tank chamber by a sliding position, and the piston from a bottom plate integrated with the cylinder. And a spring that presses and supports the cylinder upward, and is provided between the piston supported by the spring and a bottom plate of the cylinder. A pressure chamber communicating with the cylinder chamber is formed by the orifice, and the vertical position of the piston is changed between high frequency vibration and low frequency vibration by a difference between the pressure in the pressure chamber and the pressure in the cylinder chamber. The diaphragm chamber and the lower tank chamber are communicated with each other or the communication is cut off to change the spring constant.

Further, the present invention (claim 2) provides a lower tank having an expandable and contractible diaphragm, a lower tank chamber fixed to a lower portion of the diaphragm and having a volume smaller than the volume of the diaphragm chamber of the diaphragm. A second communication hole integrally formed at a central portion and higher than the lower tank and having a first communication hole communicating with the diaphragm chamber at an upper portion, and a second communication hole and a second communication hole communicating with the lower tank chamber. A hollow cylinder formed at a lower portion with a third communication hole formed adjacent to and communicating with the diaphragm chamber; and a hollow cylinder slidably housed in the cylinder chamber of the cylinder, penetrating in a plate thickness direction, and reducing a flow resistance of air. A very large orifice and said second
A piston having a communication groove having a width sufficient on the outer peripheral portion to communicate with the third communication hole over the communication hole and the third communication hole, and pressing and urging the piston upward from a bottom plate integrated with the cylinder. A pressure chamber communicating with the cylinder chamber by the orifice between the piston supported by the spring and a bottom plate of the cylinder, wherein a pressure in the pressure chamber and a pressure in the cylinder chamber are provided. By changing the vertical position of the piston between the case of high-frequency vibration and the case of low-frequency vibration depending on the difference between the diaphragm chamber and the lower tank chamber, or by interrupting the communication, the spring constant is changed. It is characterized by having comprised in.

[0010]

[Function] When the diaphragm expands and contracts while the vehicle is running,
Sometimes a pressure difference occurs between the cylinder chamber and the pressure chamber, but sometimes this pressure difference does not occur. The sliding position of the piston differs depending on the presence or absence of this pressure difference.

That is, when the vibration from the road surface (vibration of the vehicle body) is a low-frequency vibration, such as when traveling on a good road, the flow velocity of the air entering the cylinder chamber from the diaphragm chamber is low.
Slowly pass through the orifice and into the pressure chamber.

As a result, there is no pressure difference between the cylinder chamber and the pressure chamber both when the diaphragm is compressed and when it is expanded. For this reason, the piston keeps the position supported by the spring and closes the second communication hole, so that the diaphragm chamber and the cylinder chamber do not communicate with the lower tank chamber, the volume as an air spring is reduced, and the spring constant is increased. And a hard ride is obtained.

When the vibration from the road surface (vibration of the vehicle body) is high-frequency vibration, such as when traveling on a rough road, the flow velocity of the air flowing into the cylinder chamber from the diaphragm chamber or the air flowing into the diaphragm chamber from the cylinder chamber is extremely high. So fast
Since the air passing through the orifice is small and the orifice restricts, the pressure in the cylinder chamber increases or decreases rapidly while the pressure in the pressure chamber is maintained as before. A pressure difference is generated between the cylinder chamber and the pressure chamber.

As a result, when the diaphragm is compressed, the pressure in the cylinder chamber becomes higher than the pressure in the pressure chamber, so that the piston descends to open the second communication hole, and the cylinder chamber communicates with the lower tank chamber. The volume as the air spring increases, the spring constant decreases, and a soft ride can be obtained.

When the diaphragm is extended, the pressure in the cylinder chamber becomes lower than the pressure in the pressure chamber, so that the piston rises to connect the second communication hole and the third communication hole, thereby causing the diaphragm chamber and the lower tank chamber to communicate with each other. Directly communicate with each other to increase the volume as an air spring, reduce the spring constant, and obtain a soft ride.

As described above, according to the present invention, the spring constant of the air spring can be automatically changed in accordance with the state of vibration from the road surface without using any expensive sensor, solenoid valve, computer or the like. As a result, a comfortable ride and good steering stability can be obtained under all vehicle running conditions, similarly to the case where high-grade control is performed with an extremely simple and inexpensive configuration.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings. The air spring device 1 according to the present invention includes a diaphragm 2, a lower tank 3, a cylinder 4, and a piston 5
And a spring 6.

The diaphragm 2 is made of a material such as rubber so as to be extendable and contractible, and a ceiling plate 8 formed of an iron plate or the like is fixed to an upper portion thereof, and the ceiling plate is a sprung member of a vehicle, that is, a chassis frame ( (Not shown).

A spare tank such as a surge tank (not shown) or an air pressure source (not shown) is provided in a part of the ceiling plate 8.
The bottom 2a is opened by a large hole 2b, and the bottom 2a other than the hole 2b is securely secured to the lower tank 3 which is a part of the unsprung member of the vehicle. Have been.

The lower tank 3 is located below the diaphragm 2,
That is, the lower tank chamber 3 fixed to the bottom 2a and having a smaller volume than the volume of the diaphragm chamber 2c of the diaphragm 2.
The lower tank chamber is sealed by a bottom plate 3a and formed in a cylindrical shape.

The cylinder 4 is integrally provided at the center of the lower tank 3, is formed higher than the lower tank 3, has a first communication hole 4a communicating with the diaphragm chamber 2c at the upper part, and has a lower tank chamber 3c. Second communicating with
And a third communication hole 4c formed adjacent to the second communication hole 4b and communicating with the diaphragm chamber 2c at a lower portion, and a stroke regulation as an air spring is provided at an upper end portion 4d. The pad 10 is fixed by bolts 11 and nuts 12, and a bottom plate 13 is fixed in a lower part in a secret state and is formed in a cylindrical shape.

The communication hole 4c communicates directly with the diaphragm chamber 2c by a communication pipe 4e.
The periphery of e is the lower tank chamber 3c itself, and the communication of the second communication hole 4b with the lower tank chamber 3c is not interrupted by the communication pipe 4e.

The first communication hole 4a and the second communication hole 4b
The third communication hole 4c may be formed one by one, or a plurality of third communication holes 4c may be formed as shown.

The piston 5 is provided in the cylinder chamber 4 of the cylinder 4.
f, and has an orifice 5f which penetrates in the plate thickness direction and has a very high air flow resistance, and has an orifice 5f and a second communication hole 4b and a third communication hole 4c of the cylinder 4, respectively. The outer peripheral portion 5h has a communication groove 5a having a width sufficient to allow them to communicate with each other, and a pressure chamber 4g is formed below the piston and between the bottom plate 13 and the piston. ing.

The cylinder chamber 4f and the pressure chamber 4g are
The orifice 5f communicates only with the orifice 5f of the piston 5, which is formed to be very small with respect to the diameter of the piston 5. For example, the diameter of the orifice 5f is set to about 1/30 of the diameter of the piston 5. You.

The number of orifices 5f may be one or more, but the total passage area of the orifices 5f depends on the weight of the piston 5, the magnitude of the urging force of the spring 6, and the cylinder chamber 4.
It is set appropriately according to the value of the pressure difference between f and the pressure chamber 4g.

The spring 6 is for pressing and supporting the piston 5 upward from the bottom plate 13 integral with the cylinder 4, and a plurality of equal-diameter metal coil springs are used in the illustrated embodiment. However, this is not limited to a coil spring having the same diameter, but may be a coil spring having a different diameter in the length direction, or a metal spring other than the coil spring, for example, a leaf spring, a disc spring, or a non-metallic spring. An elastic body such as rubber, which is a metal material, may be used.

The spring constant of the spring 6 and the magnitude of the urging force against the piston 5 are appropriately determined based on the weight of the piston 5, the magnitude of the pressure in the diaphragm chamber 2c and the cylinder chamber 4f, the sum of the passage areas of the orifice 5f, and the like. Can be

According to the present invention, a pressure chamber 4g communicating with the cylinder chamber 4f by an orifice 5f is formed between the piston 5 supported by the spring 6 and the bottom plate 13 of the cylinder 4 with the above-mentioned structure as a main part. Depending on the difference between the pressure in the pressure chamber 4g and the pressure in the cylinder chamber 4f, the vertical position of the piston 5 is changed between high-frequency vibration and low-frequency vibration to communicate the diaphragm chamber 2c and the lower tank chamber 3c, or The communication is cut off to change the spring constant of the air spring device 1.

The present invention is configured as described above,
Hereinafter, the operation will be described. In FIG. 1, when an appropriate amount of air is supplied from the air pressure source to the diaphragm chamber 2c of the diaphragm 2 by the air hose 9, the diaphragm 2 expands to a state where it can exhibit a function as an air spring. At this time, air is also supplied to the cylinder chamber 4f of the cylinder 4 from the first communication hole 4a, and is also supplied to the pressure chamber 4g through the orifice 5f of the piston 5, and all these chambers have the same pressure. Is kept.

As a result, there is no pressure difference between the cylinder chamber 4f and the pressure chamber 4g, and the same upward force acts on the lower side of the piston 5 as on the upper side. And a size sufficient to support the weight of the piston 5.

Therefore, when the vehicle starts running, when the diaphragm 2 expands and contracts during running, sometimes the cylinder chamber 4f
A pressure difference occurs between the pressure chamber and the pressure chamber 4g, but sometimes this pressure difference does not occur. Depending on the presence or absence of this pressure difference, piston 5
, That is, the vertical position is different.

First, a case where the vehicle is running on a good road and the diaphragm 2 is compressed will be described with reference to FIG. 2. Vibration from the road surface (vibration of the vehicle body) becomes low-frequency vibration. Since the flow velocity of the air flowing into the cylinder chamber 4f from the diaphragm chamber 2c is slow, the pressure chamber 4g slowly passes through the orifice 5f as shown by the arrow A.
Get inside.

As a result, there is no pressure difference between the cylinder chamber 4f and the pressure chamber 4g. For this reason, the piston 5 maintains the position supported by the spring 6 and the second communication hole 4
b and the third communication hole 4c are closed, so that the diaphragm chamber 2c and the cylinder chamber 4f do not communicate with the lower tank chamber 3c, the volume as an air spring is reduced, the spring constant is increased, and a hard ride comfort and good Steering stability is obtained.

Next, referring to FIG. 3, a case where the vehicle is traveling on a good road and the diaphragm 2 is extended will be described. Vibration from the road surface (vibration of the vehicle body) is low-frequency vibration. Since the flow velocity of air entering the diaphragm chamber 2c from the cylinder chamber 4f into the diaphragm chamber 2c is slow as shown in FIG.
As shown by the arrow B, the gas slowly passes through the orifice 5f from the pressure chamber 4g and enters the cylinder chamber 4f.

As a result, there is no pressure difference between the cylinder chamber 4f and the pressure chamber 4g. For this reason, the piston 5 maintains the position supported by the spring 6 and the second communication hole 4
b and the third communication hole 4c are closed, so that the diaphragm chamber 2c and the cylinder chamber 4f do not communicate with the lower tank chamber 3c, the volume as an air spring is reduced, the spring constant is increased, and a hard ride comfort and good Steering stability is obtained.

When the vibration from the road surface (vibration of the vehicle body) is high-frequency vibration, such as when traveling on a rough road, air entering the cylinder chamber 4f from the diaphragm chamber 2c or air entering the diaphragm chamber 2c from the cylinder chamber 4f. Is very fast, the air passing through the orifice 5f is small, and the orifice 5f is effectively throttled.
Since the pressure in the cylinder chamber 4f increases or decreases rapidly, while the pressure in the pressure chamber 4g is maintained as before, a pressure difference occurs between the cylinder chamber 4f and the pressure chamber 4g.

Referring to FIG. 4, when the diaphragm 2 is compressed, air rapidly flows from the diaphragm chamber 2c into the cylinder chamber 4f as shown by an arrow C, but the flow path of the orifice 5f is very narrow. Only the air flows into the pressure chamber 4g.

Therefore, the pressure in the cylinder chamber 4f is
g, so that the piston 5 descends while compressing the spring against the force of the spring 6, and the second communication hole 4
b is opened, the cylinder chamber 4f communicates with the lower tank chamber 3c, air can flow into the lower tank chamber 3c as shown by the arrow D, the volume as an air spring increases, and the spring constant decreases. , A soft ride is obtained.

Referring to FIG. 5, when the diaphragm 2 is expanded, the pressure in the diaphragm chamber 2c rapidly becomes negative, so that the air in the cylinder chamber 4f rapidly flows into the diaphragm chamber 2c as shown by the arrow E. .

Therefore, the inside of the cylinder chamber 4f becomes negative pressure,
The pressing force of the spring 6 is also applied, and the piston 5 rises as shown by the arrow F, and the communication groove 5g connects the second communication hole 4b and the third communication hole 4c, and as a result, the air in the lower tank chamber 3c is As shown by the arrow G, the second communication hole 4b to the third communication hole 4
c, and flows directly into the diaphragm chamber 2c through the communication pipe 4e.

As a result, the volume of the air spring increases, the spring constant decreases, and a soft ride can be obtained.

As described above, the air spring device 1 of the present invention automatically changes the spring constant of the air spring in accordance with the state of vibration from the road surface without using any expensive sensor, solenoid valve, computer or the like. Therefore, it is possible to obtain a comfortable ride under the running conditions of all vehicles, similarly to the case of performing the high-grade control with an extremely simple and inexpensive configuration.

[0044]

According to the present invention, there is provided a lower tank having a diaphragm which can be extended and contracted as described above, a lower tank chamber fixed to a lower portion of the diaphragm and having a volume smaller than the volume of the diaphragm chamber of the diaphragm, and a center of the lower tank. A hollow cylinder that is provided integrally with the diaphragm section and communicates with the diaphragm chamber and the lower tank chamber, and an orifice that is slidably housed in the cylinder chamber of the cylinder and penetrates in the thickness direction to greatly increase the flow resistance of air. A piston configured to communicate or interrupt the communication between the diaphragm chamber and the lower tank chamber by a sliding position, and a spring that presses and supports the piston upward from a bottom plate integrated with the cylinder. Forming a pressure chamber communicating with the cylinder chamber by an orifice between the piston supported by the spring and the bottom plate of the cylinder; By changing the vertical position of the piston between high-frequency vibration and low-frequency vibration due to the difference between the pressure in the power chamber and the pressure in the cylinder chamber, the diaphragm chamber and the lower tank chamber are communicated with each other or the communication is cut off. Since the spring constant is configured to change, the volume as an air spring automatically decreases when a hard ride comfort is required, such as when driving on a good road, and the spring constant increases, making it soft as on a rough road. When riding comfort is desired, the volume as an air spring automatically increases and the spring constant can be reduced, and as a result, without using expensive parts such as solenoid valves, various sensors, and computers. It is possible to obtain an excellent air spring device that can automatically change the spring constant by sensing the state of vibration from a vehicle with an inexpensive configuration. There is an effect that can.

A first communication hole communicating with the diaphragm chamber is provided at an upper portion of a cylinder provided at the center of the lower tank, and a second communication hole communicating with the lower tank chamber is provided at a lower portion of the cylinder.
And a third communication hole which communicates with the diaphragm chamber adjacent to the second communication hole, and a second communication hole is formed in an outer peripheral portion of the piston slidably accommodated in the cylinder chamber. And the third communication hole, and a communication groove which communicates them is formed. By the effect of the orifice provided in the thickness direction of the piston, the pressure in the cylinder chamber on the upper side of the piston and the pressure on the lower side of the piston are increased. Detecting the presence or absence of a pressure difference between the first and second chambers, determining the sliding position of the piston, automatically opening and closing the second communication hole and the third communication hole by the piston, and thereby controlling the diaphragm chamber and the lower tank chamber. And cut off the communication, there is an effect that the spring constant can be automatically changed by identifying the high frequency vibration and the low frequency vibration from the road surface with an extremely simple configuration. And this conclusion There is an effect that also obtained always comfortable ride and good handling stability under any road conditions.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a configuration of an air spring device.

FIGS. 2 to 5 show the operation of the air spring device, and FIG. 2 is a longitudinal sectional view showing a compressed state of the diaphragm in the case of low frequency vibration.

FIG. 3 is a longitudinal sectional view showing an expanded state of a diaphragm in the case of low-frequency vibration.

FIG. 4 is a longitudinal sectional view showing a compressed state of a diaphragm in the case of high-frequency vibration.

FIG. 5 is a longitudinal sectional view showing an expanded state of a diaphragm in the case of high-frequency vibration.

[Explanation of symbols]

 Reference Signs List 1 air spring device 2 diaphragm 2c diaphragm chamber 3 lower tank 3c lower tank chamber 4 cylinder 4a first communication hole 4b second communication hole 4c third communication hole 4f cylinder chamber 4g pressure chamber 5 piston 5a communication groove 5f orifice 5h 6 Spring 13 Bottom plate

Claims (2)

(57) [Claims] 1. A lower tank having a telescopic diaphragm, a lower tank fixed to a lower portion of the diaphragm and having a volume smaller than a volume of a diaphragm chamber of the diaphragm, and a lower tank integrally provided at a central portion of the lower tank. A sliding cylinder having a hollow cylinder communicating with the diaphragm chamber and the lower tank chamber and an orifice slidably housed in the cylinder chamber of the cylinder and penetrating in the thickness direction to greatly increase the air flow resistance. A piston configured to communicate or interrupt the communication between the diaphragm chamber and the lower tank chamber depending on a position, and a spring that presses and supports the piston upward from a bottom plate integrated with the cylinder, A pressure communicating with the cylinder chamber by the orifice between the piston supported by the spring and the bottom plate of the cylinder. A force chamber is formed, and the vertical position of the piston is changed in the case of high-frequency vibration and the case of low-frequency vibration by a difference between the pressure in the pressure chamber and the pressure in the cylinder chamber, and the diaphragm chamber and the lower tank chamber are An air spring device characterized in that the spring constant is changed by communicating or interrupting the communication. 2. A lower tank having a telescopic diaphragm, a lower tank fixed to a lower portion of the diaphragm and having a volume smaller than a volume of a diaphragm chamber of the diaphragm, and a lower tank integrally provided at a central portion of the lower tank. A second communication hole which is formed higher than the lower tank and communicates with the diaphragm chamber at an upper portion thereof, and which is formed adjacent to the second communication hole and the second communication hole which communicates with the lower tank chamber; A hollow cylinder having a third communication hole in the lower portion communicating with the cylinder, an orifice slidably housed in a cylinder chamber of the cylinder, penetrating in the thickness direction, and having a very high air flow resistance. The outer peripheral portion has a communication groove having a width sufficient to allow the cylinder to communicate with the second communication hole and the third communication hole of the cylinder. And a spring for pressing and supporting the piston upward from a bottom plate integrated with the cylinder, and supporting the piston upward, and the orifice is provided between the piston supported by the spring and the bottom plate of the cylinder. Forming a pressure chamber communicating with the chamber, changing the vertical position of the piston between high-frequency vibration and low-frequency vibration based on the difference between the pressure in the pressure chamber and the pressure in the cylinder chamber, and An air spring device characterized in that a spring constant is changed by communicating with or cutting off the communication with the lower tank chamber.