JPH0511397Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial field of application> The invention is an air suspension system that combines an air spring that supports the load through air compression resistance and a damper that attenuates the impact mainly through oil flow resistance. Concerning pension structure.

<Prior art> As a suspension device for a vehicle, an air spring device that utilizes the compression resistance of air and a hydraulic damper device that attenuates the impact by the flow resistance of oil are integrally assembled. There is.

As such an air suspension device, for example, as disclosed in Japanese Utility Model Application Publication No. 60-171715, a main air chamber and a sub air chamber are coaxially divided and formed on the outer periphery of a hydraulic damper device.・A passage that communicates between the two sub-air chambers and a flow control valve that changes the opening area of this communication passage are integrally provided in the piston rod of the damper device, and a variable orifice mechanism is provided near the damper piston, and a variable orifice mechanism is installed inside the piston rod. An air suspension device is known in which the spring constant and damping force are changed simultaneously and stepwise by controlling the flow rate control valve and the variable orifice mechanism using a control rod inserted through the air suspension.

<Problems to be solved by the invention> However, in the case of the air suspension device having the above structure, since the spring constant and the damping force change in relation to each other, there are restrictions on the variable range of the suspension characteristics. , the compressed air supply path of the air spring, the operating device of the variable orifice mechanism, the communication path between the main and sub-air chambers, and the movable parts of the flow rate control valve for changing the flow path area of this communication path, etc. Since the stress must be concentrated on the mount portion of the piston rod where stress is likely to be concentrated, it is difficult to ensure strength and the structure is complicated.

Although it is conceivable to provide an air passage independently from the piston rod, there is a problem in ensuring the characteristics and durability of the mount rubber and the mount part becomes larger.

In view of these problems in the prior art, the main purpose of the present invention is to create a communication path between the main and sub-air chambers without complicating or increasing the size of the piston rod mount structure. The objective is to provide an improved air suspension structure.

<Means for Solving the Problems> According to the present invention, the present invention includes a piston-type cylindrical damper, a main air chamber and a sub-air chamber provided coaxially with the damper, and An air suspension structure in which the spring constant is changed depending on the communication state between the main and auxiliary air chambers,
a first pipe member disposed on the outer periphery of the outer end of the piston rod of the damper; a second pipe member disposed on the outer periphery of the first pipe member; and a second pipe member disposed on the outside of the damper. and a flow control valve,
A first passage communicating between the main air chamber and one opening of the flow control valve is formed between the piston rod and the first pipe member, and the first passage communicates with the main air chamber and one opening of the flow control valve. This is achieved by providing an air suspension structure characterized in that a second passage communicating the sub-air chamber and the other opening of the flow control valve is formed between the members.

<Function> In this way, by fitting the double pipe members coaxially around the outer periphery of the piston rod and providing air passages between them, it is possible to achieve both high rigidity and space efficiency. A communication path between the main and sub-air chambers can be provided in the mount of the piston rod. Further, if the flow rate control valve of the communication passage is provided outside the damper, there is no need to provide a movable part around the piston rod, and the mount part can be made more compact.

<Embodiments> The present invention will now be described in detail with reference to specific embodiments with reference to the accompanying drawings.

FIG. 1 shows the structure of the side of the air suspension device according to the present invention that is fixed to the vehicle body.
In addition, in FIG. 1, the right side shows the upper part.

In this air suspension device, an oil damper 1 is provided at the center of the shaft, and the lower end of a cylinder 2 that forms the outer shell of the damper is provided on the axle side (not shown) so that it can freely protrude and retract from the cylinder 2. Piston rods 3 are respectively attached to the vehicle body B side.

The oil damper 1 is of a known type that exerts a damping force by the flow resistance of oil that occurs when the oil flows through an orifice provided in a piston (not shown) that is fitted inside the cylinder 2. A pair of rod bushes 4 and 5 are fixed to the outer peripheral surface of the upper end of the piston rod 3.

The rod bush 4 is received in a cylindrical portion 6a formed at the center of the mount bracket 6, and the lower rod bush 5 has a diameter slightly enlarged downward and its upper end tapered inward. It is received within the upper end of the inner cylinder 7. A first spacer 8 is interposed between the cylindrical portion 6a of the mount bracket 6 and the upper end surface of the inner cylindrical body 7.

A radially outward flange portion 6b is formed in the middle portion of the cylindrical portion 6a. Stud bolts 9 planted in this flange portion 6b
As a result, the mount bracket 6 is fixed to the vehicle body B.

The outer circumferential portion of the flange portion 6b is bent downward, and the upper end opening of an external cylinder 10 whose lower end portion is reduced in diameter and whose middle portion is bulged is fixed to the outer peripheral portion of the flange portion 6b.

The inner cylindrical body 7 and the outer cylindrical body 10 are disposed approximately coaxially with respect to the piston rod 3, and their lower open ends are overlapped and fixed to each other, and the lower surface of the flange portion 6b and A sub-air chamber 11 is defined in the gap between the outer peripheral surface of the inner cylinder 7 and the inner peripheral surface of the outer cylinder 10.

A bump stop rubber 14 is fitted onto the outer periphery of the piston rod 3 facing the inner periphery of the internal cylinder 7 with a pair of spacers 12 and 13 sandwiched between it and the lower surface of the lower rod bush 5. The bottom surface of this bump stop rubber 14 and the cylinder 2
The contraction limit of the relative stroke between the cylinder 2 and the piston rod 3 is defined by the contact with the upper end surface of the cylinder 2 and the piston rod 3.

The upper open end of a rolling bladder 15 formed in a cylindrical shape from an elastic material such as synthetic rubber is provided with a reinforcing ring on the outer circumferential surface of the lower ends of the inner cylinder 7 and the outer cylinder 10, which are overlapped and fixed to each other. Further, the upper open end of the protective skirt 17 is fitted onto the outer circumferential surface of the rolling bladder 15 via the protective skirt 16 .

An intermediate portion (not shown) of the rolling bladder 15 is inverted inward, and its lower open end is adhered to the outer circumferential surface of a holder portion 18 formed on the outer circumference of the cylinder 2.

In this way, the internal cylinder 7 and the rolling bladder 15 define a main air chamber 19 that surrounds the upper part of the damper 1. The compression resistance force of the air sealed in the main air chamber 19 acts as a force that tends to compress the piston rod 3 and the cylinder 2, that is, as a spring that supports the load between the axle and the vehicle body.

Bump stop rubber 14 of piston rod 3
The upper part consists of a shaft part 20 with a reduced diameter and double pipe members 21 and 22 that are tightly fitted to the shaft part 20. Both the upper and lower rod bushes 4, 5 described above are fitted onto the outer peripheral surface.

Note that since the lower rod bush 5 is sandwiched between the mount bracket 6 and the first spacer 8 and receives the vehicle load via the piston rod 3, the deformation between the piston rod 3 and the inner cylinder 7 is caused only by deformation due to the load. Although sufficient airtightness can be obtained, the upper rod bush 4 is not normally subjected to loads such as rod reaction force, so the contact surface with metal is baked and at the same time a seal is placed between it and the cylindrical portion 6a. By interposing the member 4a, airtightness of the air passage, which will be described later, can be ensured.

A control rod 23 is inserted through the center of the piston rod 3 to operate a damping force adjusting rotary valve provided near a damper piston (not shown). A hydraulic passage 24 and a pair of air passages 25 and 26 are formed at the top of the piston rod 3, as well as a rotary valve 27 for adjusting the flow rate of the air passage, an actuator 28 for controlling the rotary valve 27, and a control rod 23. Each block 30 is fitted with an actuator 29 that rotates to change the diameter of an orifice that communicates between the front and rear of the damper piston. This block 30 is prevented from coming off by a nut 30a screwed onto the upper end of the piston rod 3.

Between the outer circumferential surface of the shaft portion 20 and the inner circumferential surfaces of the lower portions of the first pipe member 21 and the second pipe member 22,
A first air passage 31 is formed along the axial direction. This passage 31 is formed through slits 12 formed in the second and third spacers 12 and 13, respectively.
The main air chamber 19 and one of the air passages 25 are communicated via the main air chamber 19 and the air passage 25 via the air passages 13a and 13a (see FIGS. 2 and 3).

Between the outer circumferential surface of the first pipe member 21 and the inner circumferential surface of the second pipe member 22, there is provided a second air passage which communicates between the intermediate portions of both the upper and lower rod bushes 4 and 5 and the other air passage 26. An air passage 32 is formed.
This passage 32 is connected to the sub air chamber 1 through a slit 8a (see FIG. 4) formed in the first spacer 8.
It is connected to 1.

On the other hand, the rotary valve 27 is connected to the valve case 3.
It consists of a cylinder hole 34 formed in the cylinder hole 3 and a valve body 35 rotatably fitted into the cylinder hole 34, and a through hole 36 provided in the valve body 35 and an opening 37 provided in the valve case 33. By changing the alignment state of the air passages 25 and 26, the degree of communication between the air passages 25 and 26 provided inside the block 30 can be varied.

The rotary valve 27 is formed with an air suction/discharge passage 38 that communicates with the cylinder hole 34, and is connected to a compressed air supply source via a separate solenoid valve (not shown). Both air chambers 19,
Air can be supplied to and discharged from 11.

Next, the operation of the above embodiment will be explained.

The spring constant in an air spring changes with the volume of the air chamber relative to the stroke. When the valve body 35 of the rotary valve 27 is rotated to cut off the communication between the through hole 36 and the first air passage 31, the communication between the main air chamber 19 and the sub air chamber 11 is cut off. As a result, only the volume of the main air chamber 19 produces a spring action, resulting in a high compression ratio and a high spring constant. Next, when the through hole 36 and the opening 37 are aligned, the shaft portion 20 and both the first and second pipe members 21 and 2 are aligned.
Both the first and second passages 31 and 32 formed between
Since the main air chamber 19 and the sub-air chamber 11 communicate with each other through the cylinder hole 34, both the main and sub-air chambers 1
The combined volume of 9 and 11 produces a spring action, resulting in a low spring constant. In this way, the Lord
By changing the state of communication between the secondary air chambers 19 and 11 between the through hole 36 and the opening 37, the spring constant can be changed arbitrarily.

Furthermore, by letting compressed air in and out from the air suction and discharge passage 38, both the main and auxiliary air chambers 19 and 11 are
By appropriately adjusting the internal pressure of the spring, an appropriate spring constant can be obtained at all times in response to fluctuations in the sprung mass load due to, for example, an increase or decrease in the number of occupants.

<Effects of the invention> As described above, according to the invention, the spring constant variable device and the damping force variable device are centrally arranged at the tip of the piston rod, and the spring constant and damping force are controlled. It is possible to do this independently.

In addition, by providing the communication passage between the main air chamber and the sub-air chamber coaxially with the piston rod, and by providing the flow control valve outside the damper, the movable part and the piston rod can be easily connected without compromising the compactness of the device. The mount portion of the piston rod can be made smaller without impairing the characteristics and durability of the mount rubber.

Furthermore, since the actuator and piping members can all be disposed inside the vehicle body, this is advantageous in terms of protection from moisture and dust, and is also effective in improving maintainability.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of the main part of an air suspension device based on the present invention. FIG. 2 is an enlarged plan view of the second spacer 12. FIG. 3 is an enlarged plan view of the third spacer 13. FIG. 4 is an enlarged plan view of the first spacer 8. FIG. 1...Oil damper, 2...Cylinder, 3...
Piston rod, 4... Upper rod bush, 4
a... Seal member, 5... Lower rod button,
6...Mount bracket, 6a...Cylindrical part,
6b...Flange portion, 7...Inner cylinder, 8...
First spacer, 9... Stud bolt, 10...
...External cylinder, 11...Sub-air chamber, 12...Second spacer, 13...Third spacer, 12a, 1
3a...Slit, 14...Bump stop rubber, 15...Rolling bladder, 16...Reinforcement ring, 17...Protection skirt, 18...Holder part, 19...Main air chamber, 20...Shaft part, 21 ……
First pipe member, 22... second pipe member,
23... Control rod, 24... Hydraulic related passage, 25, 26... Air passage, 27... Rotary valve, 28, 29... Actuator, 30
...Block, 30a...Natsuto, 31...1st
air passage, 32... second air passage, 33...
Valve case, 34... Cylinder hole, 35... Valve body, 36... Through hole, 37... Opening, 38...
Air intake and exhaust passage.

Claims (1)

[Claims for Utility Model Registration] A piston-type cylindrical damper, a main air chamber and a sub-air chamber provided coaxially with the damper, and a spring constant determined by the communication state between the main and sub-air chambers. The air suspension structure is configured to change the air suspension structure, and includes: a first pipe member disposed on the outer periphery of the outer end of the piston rod of the damper; and a first pipe member disposed on the outer periphery of the first pipe member. 2 pipe members, and a flow rate adjustment valve disposed outside the damper, and the main air chamber and one opening of the flow rate adjustment valve are located between the piston rod and the first pipe member. A first passage communicating between the first pipe member and the second pipe member is formed, and a second passage communicating the auxiliary air chamber with the other opening of the flow control valve is formed between the first pipe member and the second pipe member. An air suspension structure characterized by the formation of an air suspension structure.