JPS6148446B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automobile suspension, and more particularly to an improvement in a fluid suspension that utilizes the compressive elasticity of a gas such as air.

Conventionally, as this type of fluid suspension, as disclosed in Japanese Patent Application Laid-Open No. 50-100469, each suspension mechanism in a two-wheeled vehicle has a volume that increases with the vertical displacement of the vehicle body and wheels. Two types of air chambers are provided: a first air chamber whose volume changes, and a second air chamber whose volume always remains constant, and by communicating these two types of air chambers under normal conditions, a low spring constant is obtained and ride comfort is improved. On the other hand, when a high spring constant is required such as during sudden braking, the communication between the two chambers is cut off to create a hard state where the compression volume is reduced and the number of springs is increased. A device that prevents forward tilting (nose dive) is known. However, since two types of air chambers are provided for each suspension mechanism, this system tends to complicate the overall configuration when applied to a four-wheeled vehicle.

In addition, as disclosed in, for example, Japanese Utility Model Application Publication No. 56-39311, etc., a second
It has been proposed that the air chamber be shared between the left and right suspension mechanisms to simplify the overall configuration. In other words, in this system, when a large load is applied to either the left or right suspension mechanism, such as during cornering, communication between the shared second air chamber and each first air chamber is cut off using respective open/close valves. , only the first air chamber of each suspension mechanism is used in a hard state to eliminate left-right imbalance and prevent rolling.

However, in this conventional suspension, an opening/closing valve is provided for each air chamber of the left and right suspension mechanisms, so if one opening/closing valve fails, the spring constant of the air spring in the suspension mechanism will be unbalanced between the left and right. , and the riding comfort becomes extremely poor.
There are also disadvantages in terms of structure, such as an increase in the number of parts and a disadvantage in terms of cost.

Therefore, by using a single opening/closing valve to simultaneously switch between communication and communication cutoff between the first and second air chambers on the left and right, even if the opening/closing valve fails, the spring constants on the left and right sides will be unbalanced. In addition, it is possible to reduce the number of parts and reduce costs.

However, in a suspension system in which the on-off valve is used to control communication and cut-off of both air chambers, when the on-off valve is closed, communication between the two air chambers is completely cut off. The following problems arise. In other words, when the air pressure in the fixed volume second air chamber is changed and adjusted in the hard state with the on-off valve closed, and then the on-off valve is opened to communicate both air chambers and switched to the soft state, air moves rapidly between both chambers. This causes the vehicle height to increase or decrease rapidly.

Additionally, if you park on a slope in the soft mode, the center of gravity shifts and the vehicle tilts back and forth, and if you close the on-off valve and switch to the hard mode and then drive on a flat road, the vehicle will remain slumped forward or backward. .

Furthermore, if the air in the first air chamber were to leak into the second air chamber due to the large load applied to the suspension while driving in the hard state, the posture of the vehicle body would change, and this change in posture could be corrected by opening the opening/closing valve. This problem persists unless the state is changed.

In view of these points, the invention provides communication between the first air chamber and the second air chamber through a communication path that is separate from the normal communication path and has a large resistance. Even if a pressure difference occurs within the air chamber, the pressure difference is gradually resolved without significantly affecting the overall spring characteristics, thereby preventing sudden changes in vehicle height when switching spring characteristics and improving the vehicle body. The purpose is to stabilize the running posture.

In order to achieve this object, the present invention has a first fluid chamber that is provided in each of the left and right suspension mechanisms of an automobile, and whose volume changes as the vehicle body and wheels move up and down, and a first fluid chamber that maintains a constant volume at all times. a second fluid chamber that is maintained, a mutually independent left and right communication passage connecting each of the first and second fluid chambers, an opening/closing valve that simultaneously opens and closes the left and right communication passages, and each of the first fluid chambers. and an orifice means for communicating the first and second fluid chambers by bypassing the on-off valves of the communication passages, thereby reducing the pressure difference generated between the two fluid chambers when the on-off valves are closed. This is done by using an orifice means to gradually eliminate the problem.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

In FIG. 1, 1a and 1b are left and right suspension mechanisms installed between the car body and the front or rear wheels, respectively. Sealed first fluid chambers 2a, 2b whose volumes change with the vertical displacement of the vehicle body and wheels are formed, and compressed air is sealed in each of the first fluid chambers 2a, 2b.

On the other hand, reference numeral 3 designates a sealed second fluid chamber which is composed of an accumulator and maintains a constant volume at all times, and compressed air is sealed inside the second fluid chamber. The second fluid chamber 3 and each of the first fluid chambers 2a, 2b are communicated with each other by mutually independent left and right communication passages 4a, 4b, and a middle portion of the communication passages 4a, 4b is provided with a communication passage. One electromagnetic opening/closing valve 5 is provided to control the opening and closing of 4a and 4b at the same time. That is, the opening/closing valve 5 is normally in the normal position A and opens the communication passages 4a and 4b at the same time, allowing the second fluid chamber 3 and each of the first fluid chambers 2a and 2b to communicate with each other, thereby opening the suspension mechanisms 1a and 1b. The spring constant of is lowered to create a soft state, and at the time of cornering, etc., it is set to the offset position and closes the communication passages 4a and 4b at the same time, thereby preventing communication between the second fluid chamber 3 and each of the first fluid chambers 2a and 2b. It operates to shut off and increase the spring constant of the suspension mechanisms 1a, 1b to put them in a hard state.

Furthermore, the second fluid chamber 3 (accumulator)
The specific structure of the on-off valve 5 will be described in detail with reference to FIG. 2. A circular recess 6 that constitutes the wall of the valve chamber 11, which will be described later, is formed on the outer surface of one side wall of the second fluid chamber 3. A pair of holes 7a, 7 are provided at the peripheral edge of the bottom wall of the recess 6 and communicate with the second fluid chamber 3.
b also has a pair of holes 9a, 9 in the center thereof communicating with each of the first fluid chambers 2a, 2b via passages 8a, 8b formed in one side wall of the second fluid chamber 3, respectively.
b are opened respectively, and the passages 8a, 8b, holes 9a, 9b, recess 6 (valve chamber 11) and holes 7a,
7b constitutes a part of the communication paths 4a, 4b.

Further, a part of the fixed core 10 of the on-off valve 5 is fitted in the recess 6 in an airtight manner.
A valve chamber 11 is formed between the recess 6 and the recess 6 . A valve plunger 12 is slidably supported through the fixed core 10, and a valve body 13 that can be seated on the bottom wall of the valve chamber 11 (bottom wall of the recess 6) is formed at the tip of the valve plunger 12. By using the valve body 13 to open and close two central holes 9a and 9b that communicate with each of the first fluid chambers 2a and 2b, the communicating passages 4a and 4b are simultaneously opened and closed. On the other hand, a movable core 14 is formed at the rear end of the valve plunger 12, and a valve spring 15 is compressed between the movable core 14 and the fixed core 10 to bias the valve body 13 in the valve opening direction. has been done. Further, the movable core 14 is arranged around the fixed core 10.
The valve body 13 is sucked toward the fixed core 10 side.
A drive solenoid 16 is disposed to close the valve against the biasing force of a valve spring 15, and the drive solenoid 16 is connected to a power source and a control switch (both not shown) via a lead wire 17. The communication passage 4a,
4b are closed at the same time.

Each passage 8a, 8b inside one side wall (accumulator wall portion) of the second fluid chamber 3 is connected to an orifice 18a, 18b formed in the one side wall, respectively.
The first fluid chambers 2a, 2b and the second fluid chamber 3 are communicated with each other through the orifices 18a, 18b, bypassing the on-off valve 5. In addition, in Figure 2, 1
Reference numeral 9 denotes an air hole for replenishing and removing air from the second fluid chamber 3 (accumulator).

Therefore, in the above embodiment, the left and right suspension mechanisms 1a,
When lowering the spring constant of 1b to create a soft state, open the control switch and open/close valve 5.
Set it to the open/closed state (normal position A). In this state, the communication passages 4a and 4b are both open and the second fluid chamber 3 and the first fluid chambers 2a and 2b communicate with each other, thereby increasing the compressed volume of the air spring in each suspension mechanism 1a and 1b. As a result, the spring constant becomes lower, and riding comfort etc. can be improved.

On the other hand, when the spring constants of the suspension mechanisms 1a and 1b are increased to make them hard during high-speed driving or cornering, the control switch is closed and the drive solenoid 16 of the on-off valve 5 is energized. Close the valve (offset position B). In this state, each communication path 4a, 4b
are closed together, and the communication between the first fluid chambers 2a and 2b and the second fluid chamber 3 is substantially cut off, and as a result, the compressed volume of the air spring in each suspension mechanism 1a and 1b becomes smaller, and the spring constant thereof decreases. Therefore, it is possible to improve rolling resistance performance and the like, thereby improving running stability.

In this case, since one opening/closing valve 5 simultaneously opens and closes the two communicating passages 4a, 4b to switch between the soft state and the hard state, even if the opening/closing valve 5 fails, the left and right suspension mechanisms 1a, 1b
The spring constant is maintained either high or low at the same time, so there is no imbalance, and the number of parts can be reduced, leading to cost reductions.

In addition, each first
Since the fluid chambers 2a and 2b communicate with the second fluid chamber 3 by bypassing the on-off valve 5, the problems of the conventional example in which communication is not provided through the orifices 18a and 18b can be solved at once. I can do it. That is, when high pressure air is replenished into the second fluid chamber 3 in a hard state where the on-off valve 5 is closed and the second fluid chamber 3 is disconnected from the first fluid chambers 2a and 2b, the second fluid chamber 3 is refilled with high pressure air. 3 and each first fluid chamber 2
There is a difference in air pressure between a and 2b, and this pressure difference causes the air in the second fluid chamber 3 to flow through each orifice 18.
a, 18b into the respective first fluid chambers 2a, 2b, and finally both fluid chambers 2a, 2b,
The air pressure within 3 is balanced. Therefore, when the opening/closing valve 5 is subsequently opened to switch to a soft state in which both fluid chambers 2a, 2b, and 3 are completely communicated, air in the second fluid chamber 3 rapidly flows into each of the first fluid chambers 2a, 2b. Therefore, the vehicle height can be prevented from rising suddenly. Conversely, when air is removed from the second fluid chamber 3, the air pressures in both fluid chambers 2a, 2b, 3 gradually become equal due to the orifices 18a, 18b, and the vehicle height is reduced. Rapid downward changes can be prevented.

Additionally, if you park on a slope in the soft mode, the center of gravity shifts and the vehicle leans, but when you switch to the hard mode and start driving on a flat road, the front and rear suspensions shift as the center of gravity returns on the flat road. Each first fluid chamber 2 in mechanisms 1a and 1b
A difference in air pressure occurs between the second fluid chamber 3 and the orifices 18a and 2b, and this difference in air pressure causes each orifice 18a,
Air flows through the fluid chambers 2a, 2b, 3
The air pressure inside becomes equal. As a result, the tilt of the vehicle body caused by parking on the slope is naturally corrected, the posture of the vehicle body is maintained normally, and the running posture can be stabilized.

Furthermore, while driving in the hard state, a large load is applied to each suspension mechanism 1a, 1 due to bump movements, etc.
b, the air in each first fluid chamber 2a, 2b resists the closing force of the on-off valve 5 and closes the second fluid chamber 3.
Even if a large amount of air leaks to the second fluid chamber 3 and the balance of air pressure between the second fluid chamber 3 and each of the first fluid chambers 2a, 2b is disrupted and the posture of the vehicle body changes, the second
The air in the fluid chamber 3 flows through each orifice 18a, 18b.
By returning to each first fluid chamber 2a, 2b through the inside, the air pressure between the two fluid chambers 2a, 2b, 3 becomes equal, and the vehicle body returns to its normal posture, thereby maintaining a stable running posture. I can do it.

In addition, in this way, the second fluid chamber 3 and each first fluid chamber 2
There is a concern that by communicating the fluid chambers 2a, 2b with the orifices 18a, 18b, the effect of shutting off communication between the fluid chambers 2a, 2b, 3 with the on-off valve 5 when the hard state is set is reduced. In reality, the orifices 18a and 18b, which have small passage diameters,
Since short-cycle air pressure fluctuations within the fluid chambers 2a and 2b are substantially blocked, the hard state can be stably maintained without much adverse effects.

FIG. 3 shows a modification of the orifice means (in addition,
(The same parts as in FIG. 2 are given the same reference numerals and detailed explanation thereof is omitted). Orifice 1 formed on one side wall of
8a and 18b, but instead of this, a large number of small holes made of foamed polystyrene resin etc. are formed on the tip surface of the valve body 13 of the on-off valve 5 (the surface that opens and closes the holes 9a and 9b that open into the valve chamber 11). A porous sheet 20 is fixed to the porous sheet 20 so that the porous sheet 20 functions as an orifice means for communicating the two fluid chambers 2a, 2b, and 3.

Therefore, in this modification, the same effects as in the above-mentioned embodiment can be achieved, and in addition, since it is only necessary to fix the porous sheet 20 to the distal end surface of the valve body 13 of the on-off valve 5, it can be easily performed. It has the advantage of being easy to manufacture.

Incidentally, in the present invention, as in the above embodiment, one on-off valve 5 connects the left and right communicating passages 4a, 4 which are independent from each other.
In addition to the fluid type suspension in which b is opened and closed at the same time, it is also possible to use a fluid suspension in which the valves are opened and closed at the same time using two on-off valves each having a communication passage (as explained in the conventional example). Of course, it can be applied.

As explained above, according to the present invention, there is a pair of first fluid chambers on the left and right whose volume changes with the vertical displacement of the vehicle body and each wheel, and a second fluid chamber that maintains a constant volume.
In a hydraulic suspension for an automobile, the fluid chambers are communicated with each other through mutually independent left and right communication passages, and the left and right communication passages are simultaneously opened and closed by on-off valves to switch the spring characteristics of each suspension mechanism. Since the first fluid chamber and the second fluid chamber are communicated with each other by an orifice means that bypasses the on-off valve, a sudden drop occurs between each first fluid chamber and the second fluid chamber when the on-off valve is closed. The above-mentioned orifice means can gradually eliminate the pressure difference without significantly affecting the overall spring characteristics, thereby preventing a large change in vehicle height when changing the spring characteristics, and improving the running posture of the vehicle body. This makes it possible to stabilize the system, thereby contributing to the practical use of fluid suspensions.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall schematic configuration diagram, FIG. 2 is an enlarged cross-sectional view of main parts, and FIG.
The figure is a view corresponding to FIG. 2 showing a modification of the orifice mechanism. 1a, 1b... Suspension mechanism, 2a, 2
b...First fluid chamber, 3...Second fluid chamber, 4a, 4
b... Communication path, 5... Opening/closing valve, 11... Valve chamber, 13... Valve body, 18a, 18b... Orifice, 20... Porous sheet.

Claims (1)

[Claims] 1. A first fluid chamber that is provided in each of the left and right suspension mechanisms of an automobile and whose volume changes with the vertical displacement of the vehicle body and wheels, a second fluid chamber that always maintains a constant volume, and each of the above-mentioned first fluids. mutually independent left and right communication passages connecting the chamber and the second fluid chamber, opening/closing valves that simultaneously open and close the left and right communication passages, and connecting the first fluid chamber and the second fluid chamber to each of the communication passages. An automobile suspension characterized by comprising orifice means communicating by bypassing an opening/closing valve.