JPS6080920A - air spring suspension - Google Patents

Abstract

PURPOSE:To enable to adjust a spring constant and a damping force with a simple structure by forming two air chambers so as to enclose the upper end of a shock absorber in a suspension and connecting both air chambers together in mutual communication through a valve. CONSTITUTION:The first and the second housings 40, 42 are concentrically fixed to the upper end of a piston rod 28 which is upwardly projected from the cylinder 26 of a shock absorber 12 and a resilient member 52 like a diaphragm is stretched between the cylindrical portion 45 of the outer housing 40 and the cylindrical member 56 fixed to the cylinder 26 to form the first air chamber 18. Further, the second air chamber 20 is formed in the inside of the inner housing 42 by fitting a fixed piston 60 provided on the upper end of the cylinder 26. The communication and the interruption between air chambers 18, 20 can be carried out by the valve 22 which is provided to cross both housings 40, 42 in a radial direction and it is possible to adjust a spring constant and a damping force by operating the valve 22 by means of the operating means 24.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to air spring suspensions, and more particularly to strut type air spring suspensions.

(Prior Art) A strut type air spring suspension includes a shock absorber and an air spring.

This air spring has a housing attached to the piston rod of the shock absorber, and a diaphragm is passed between the housing and the cylinder of the shock absorber.
An air chamber formed by a housing and a diaphragm is filled with compressed air, and the vehicle height can be adjusted by changing the volume of the air chamber.

By the way, in the conventional air spring suspension,
When the vehicle height is set to a predetermined value, the volume of the air chamber remains constant, so it is not possible to adjust the damping force by changing the volume of the air chamber.

Next, although it is not directly related to adjusting the damping force, if the diaphragm breaks, the air in the air chamber will escape.
The vehicle height has dropped rapidly.

(Object of the Invention) Therefore, an object of the present invention is to improve the spring constant and damping force by using two air chambers independently or as one air chamber at a predetermined vehicle height. The aim is to obtain an adjustable air spring suspension.

Another object of the present invention is to provide an air spring type suspension that can prevent a sudden drop in vehicle height when a diaphragm is damaged.

(Structure of the Invention) The present invention includes first and second air chambers formed to surround an upper end of a shock absorber, a valve capable of communicating and blocking the first and second air chambers, and means for actuating a valve.

(Example) Examples of the present invention will be described below with reference to the drawings.

The air spring type suspension 10, as shown in FIG.
The upper end of the shock absorber 12 is connected to the vehicle body 16 via an upper support 14, and includes a first air chamber 18, a second air chamber 20, a valve 22, and an actuating means 24. .

The shock absorber 12 includes a cylinder 26 and a piston rod 28 that is connected to a piston that is slidably disposed inside the cylinder 26 and projects from the cylinder 26 to the outside. The piston is provided with a valve that allows oil or other liquid contained within the cylinder to flow when the piston rod 28 is extended and retracted. Since the above configuration is well known, illustration thereof is omitted. In addition to the so-called twin-tube type shock absorber 12 that includes an inner shell and an outer cylinder, a so-called monotube type that includes only a single cylinder is used.

The upper support 14 includes an outer cylinder 30 having a flange 31, an inner cylinder 32 having a flange 33, and an elastic body 34 vulcanized and bonded to both cylinders. The upper sabot 14 is fixed to the vehicle body 16 by screwing together the upper sabot 38.

A first housing 40 and a second housing 42 are secured to the piston rod 28. The first housing 40 has a circular ceiling portion 44 and a cylindrical portion 45 that is integrally connected to the ceiling portion 44 . Further, the second housing 42 includes a circular ceiling portion 46 and a cylindrical portion 47 that is integrally connected to the ceiling portion 46.
and has. The ceiling parts 44 and 46 of both housings are overlapped, an O-ring 48 is interposed between them as shown in FIG. The flange 33 of the inner cylinder of the upper sabot 14 is placed on the upper side of the portion 44, and the nut 50 is screwed onto the piston rod 28, so that the first and second housings 40, 42 are fixed to the piston rod 28.

The elastic member 52 is a cylindrical diaphragm made of rubber. This elastic member 52 is folded back approximately at the center, and its outer end is sandwiched between the cylindrical portion 45 of the first housing 40 and the ring 54, and the ring 54 is caulked so that the outer end It is fixed to the housing 40. The inner end of the elastic member 52 is applied to a cylindrical member 56 welded to the cylinder 26, and is fixed to the cylindrical member 56 by caulking a ring 58. As a result, the first air chamber 18 is formed by the elastic member 52 and the first housing 40 together.

By providing the cylindrical member 56, the capacity of the first air chamber 18 can be increased, and the elastic member 52 is prevented from coming into direct contact with the outer peripheral surface of the cylinder 26, thereby reducing deterioration of the elastic member 52 due to heat. This is preferable because it can be done. However, this cylindrical member 56 may be omitted, in which case the inner end of the elastic member 52 is directly fixed to the cylinder 26.

The elastic member 52 can also be a bellows.

A fixed piston 60 is provided at the upper end of the cylinder 26 of the shock absorber 12. This fixed piston 60 has an orifice 62 that acts to restrict the flow of air and an O-ring 64 attached to its outer periphery, and allows the piston rod 28 to move through it, while the second housing 4
The two cylindrical portions 47 are movably fitted in an airtight manner.

As a result, the second air chamber 20 is formed by the fixed piston 60 and the second housing 42 together. Second
The housing 42 extends into the cylindrical member 56, and the orifice 62 opens into a space 66 between the second housing 42 and the cylinder 26, communicating the second air chamber 20 with this space 66. . A radial hole 68 and an axial hole 70 connected to the hole 68 are bored in the piston rod 28, and a hose 72 connected to the piston rod 28 with a nut 50 passes through the hole 70 and the hole 68 into the air chamber. 20
It is connected to hehe. Hose 72 is connected to an air supply (not shown).

By providing the orifice 62, the dynamic spring constant can be determined by the size of its diameter, making it easy to vary the spring constant according to the specifications of the same vehicle model.

The valve 22 includes a casing 74, a valve body 76, and a plug nut 78, as shown in detail in FIG.

The casing 74 is formed of a cylinder and has a first
It extends through the cylindrical part 45 of the second housing 40 to the cylindrical part 47 of the second housing 42, and its inner diameter-reduced end is fitted into the cylindrical part 47, and the outer periphery of the casing 74 is welded. and the casing 74 is connected to the second housing 42
Fixed. This casing 74 has a hole 80 opening into the first air chamber 18 . The casing 74 is fixed to the first /\ housing 40 by a nut 73 screwed onto its outer periphery, and the gap with the first housing 40 is made airtight by an O ring 75.

The valve body 76 has a radial hole 82 and an axial hole 84 . When the valve body 76 is inserted into the casing 74 and its inner shoulder 77 abuts the reduced diameter portion of the casing 74,
Hole 82 is aligned with hole 80 in casing 74 . hole 82
2, the first air chamber 18 communicates with the second air chamber 20 through a hole 80 in the casing 74, a hole 82, and a hole 84 in the valve body 76. However, the valve body 76 is 90'
When rotated, the hole 80 of the casing 74 and the hole 82 of the valve body 76 are completely out of alignment, and the first air chamber 18 and the second air chamber 20 are cut off.

The plug nut 78 is screwed into the casing 74 and passes through the valve stem 86 of the valve body 76. O-rings 88 and 90 are arranged between the plug nut 78 and the casing 74 and between the plug nut 78 and the valve stem 86, respectively, to keep the gaps airtight.

The means 24 for actuating the valve 22 is an electric motor in the illustrated example. The actuating means 24 includes an attachment 92, which is abutted against a bracket 94 fixed to the cylindrical portion 45 of the first housing, and the actuating means 24 is fixed to the first housing 40 by tightening a screw 96. . The valve stem 86 of the valve body 76 is attached to the shaft 98 of the actuating means 24.
The flat end of is inserted non-rotatably.

A pressure sensing means 99 is connected to the first air chamber 18 . This pressure detection means 99 is damaged when the elastic member 52 is damaged.
When the pressure inside the air chamber 18 decreases, a signal is output.

In the example shown in FIG. 3, the valve 100 includes a casing 102;
It includes a valve body 104 and a valve seat 106. casing 10
2 is disposed between the first housing 40 and the second housing 42, and the connecting portion 108 is connected to the first housing 4.
It protrudes to the outside through the cylindrical portion 45 of 0. Connection part 1
08 is screwed into the first housing 40 by an O-ring 112 supported by the
The gap between the two is said to be airtight. A cap 116 connected to a hose 114 is screwed into the connecting portion 108 . Hose 114 is connected to an air supply or pump and is supplied with compressed air or pressurized fluid. In the illustrated example, compressed air or hydraulic fluid is the means for actuating valve 100.

The valve body 104 is a spool that slides inside the casing 102 in the axial direction, and has a plurality of axial holes 118 and a circumferential groove 120 continuous with the holes 118. Seal members 122 are attached to the upper and lower end surfaces of the valve body 104. Insert this valve body 104 into the casing 102,
A spring 124 is applied to the lower side, the valve seat 106 is arranged at the open end of the casing 102, the casing 102 is caulked to fix the valve seat 106 to the casing 102, and the valve body 106 is fixed to the casing 102.
04 is housed in a casing 102. Valve body 104
is biased upward by a spring 124, and the upper seal member 122 abuts against the casing 102. At this time, the groove 120 of the valve body 104 was provided in the casing 102. It communicates with a hole 126 that opens into the second air chamber 20.

When compressed air or pressurized liquid is supplied to the connecting portion 108, the valve body 104 moves downward against the spring force of the spring 124,
The lower seal member 122 hits the valve seat 106 and the groove 1
20 and hole 126 are blocked.

Further, when the elastic member 52 is damaged and the pressure in the first air chamber 18 decreases, a pressure difference is generated between the elastic member 52 and the second air chamber 20, and the valve body 104 is pushed down, causing the lower seal member 122 to close to the valve body 104. Upon hitting the seat 106, the second air chamber 20 is blocked.

The rest of the configuration of the example in FIG. 3 is the same as in FIG. 1.

In the example shown in FIG. 4, only the first housing 40 is fixed to the piston rod 28 of the shock absorber 12, and this housing 40 and the cylindrical member 56 have elastic
Members 52 are each fixed. On the other hand, a conical fixed piston 130 is attached to the cylinder 26 of the shock absorber 12. The fixed piston 130 movably passes through the piston rod 28, is movably fitted into the first housing 40, and is kept airtight by an O-ring 132 attached to its outer periphery. As a result, the first housing 40 and the elastic member 52
The first housing 40 and the fixed piston 130 form a first air chamber 18, and the first housing 40 and the fixed piston 130 form a second air chamber 20.

A passageway 134 is attached to the housing 40 that opens below the first air chamber 18 and above the second air chamber 20, respectively. A valve 136 is incorporated into this passage 134. The valve 136 includes a valve body 138 having a hole 137 opened in the radial direction.
When the valve 136 is rotated by 90 degrees, the valve 136 changes from the closed state to the open state, and the first and second air chambers communicate with each other.

(Operation of the embodiment) (a) When changing the spring constant and damping force: The valve 22 is actuated by the actuating means 24, and the first air chamber 18 and the second air chamber 20 are communicated with each other. When compressed air is supplied through the hose 72 in this state, the first and second air chambers 18,20 are filled with the compressed air, and the vehicle height is determined by adjusting the filling amount. When the automobile suddenly starts, suddenly stops, or turns, the actuating means 24 operates the valve 22 to shut off the first air chamber 18 and the second air chamber 20. and the second air chamber 20 constitute an independent air spring, so the result is the same as if two air springs were arranged in parallel.
Spring constant can be changed. Also, when the fixed piston 60 is provided with the orifice 62 as shown, the dynamic spring constant and damping force can be varied.

Next, when the automobile is traveling steadily, the actuating means 24 operates the valve 22 to open the first air chamber 18 and the second air chamber 20.
When these are connected, a single air spring having an air chamber with a size equal to the volume of the rain air chamber is formed, so the damping force and spring constant become small.

When using the valve of FIG. 3, in order to shut off the valve 100, the force due to the pressure acting on the valve body 104 from the fluid led to the connection part 108 is applied to the spring force of the spring 124 and the first air chamber. It is only necessary to introduce a pressure to the connecting portion 108 that exceeds the force acting on the valve body 104 due to the pressure of the valve body 104 .

(b) Suppressing the reduction in vehicle height when the elastic member is damaged: When the elastic member 52 is damaged, the pressure within the first air chamber 18 is reduced. This decrease is detected by the pressure sensing means 99, and the actuating means 24 is actuated via a suitable control device (not shown) to close the valve 22. Then, since the vehicle height is maintained by the second air chamber 20, a sudden drop in vehicle height can be suppressed.

When using the valve 100 of FIG. 3, the pressure of the fluid at the connection 108 is adjusted so that the force acting on the valve body 104 due to the pressure of the fluid introduced into the connection 108 slightly exceeds the spring force of the spring 124. , keep pressure applied at all times. Then, when the force due to the pressure in the first air chamber 18 is substantially eliminated, the valve body 104 is pushed down by the pressure of the fluid and blocks the first air chamber 18 and the second air chamber 20. According to this operation, no pressure sensing means is required.

The above operation can be performed on all wheels at the same time or on each wheel individually.

(Effect of the invention) The effects achieved by the present invention are as follows.

a) Since the damping force and spring constant of the air spring can be changed, the damping force and spring constant can be reduced during normal driving to ensure ride comfort, and when steering, sudden starts, sudden stops, etc.
Maneuverability and stability can be ensured by increasing damping force and spring constant.

b) Since an air chamber can be secured even when the elastic member is damaged, a sudden drop in vehicle height can be prevented, and a decrease in maneuverability and stability due to sudden movements of the vehicle body can be prevented.

C) The damping force and spring constant can be increased or decreased by communicating or blocking the two air chambers, so there is no need to modify the shock absorber, and it is possible to share the shock absorber in the same car model, reducing costs. Can be reduced. Moreover, the structure is simple.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the main parts of the suspension according to the present invention, FIG. 2 is an enlarged cross-sectional view showing the valve in FIG. 1, FIG. 3 is a cross-sectional view showing another example of the valve, and FIG. FIG. 7 is a cross-sectional view of main parts of another example of the suspension. lO; suspension, 12i shock absorber, 18; first air chamber, 20; second air chamber, 22, i
oo, 136; valve; 24. 140; actuation means; 40; first housing; 42; second housing; 52; elastic member. Agent Patent Attorney Nobuyuki Matsunaga 6 Figure 1 2 Figure 2

Claims (1)

[Claims] First and second air chambers formed to surround an upper end of a shock absorber, a valve capable of communicating and blocking the first and second air chambers, and means for operating the valve. Including, air spring suspension.