JPH0539925Y2 - - 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 the compression resistance of air and a damper that attenuates the impact mainly through the flow resistance of oil. The present invention relates to a shock absorbing device.

<Prior Art> As a suspension device for a vehicle, one in which an air spring device that utilizes air compression resistance and a hydraulic damper device are integrally assembled is sometimes used.

As such an air suspension device, for example, as disclosed in Japanese Utility Model Application Publication No. 60-241538, the air chamber is divided into a main air chamber and a sub-air chamber, and a communication passage between the two air chambers is opened. There is a type of damper that absorbs the expansion and contraction stroke of the damper by changing the spring constant by changing the area and at the same time forming a part of the air chamber with a flexible elastic cylinder. It is being

By the way, in such an air suspension device, it is desirable that the passage communicating between the main and auxiliary air chambers be the shortest route in order to reduce flow resistance and improve response. It is preferable that a communication path is provided in the partition wall between both the air chambers.

<Problems to be solved by the invention> However, the above-mentioned communication passage must be provided with a valve mechanism for changing the opening area of the communication passage, a remote control device for this valve mechanism, etc., and the structure is complicated. Therefore, a rise in manufacturing costs was unavoidable.

In view of the problems of the prior art, the main purpose of the present invention is to provide an air suspension device that has a simple structure and can form a communication path between the main and sub air chambers at a relatively low cost. It is about providing.

<Means for Solving the Problems> According to the present invention, this purpose is to provide communication between the piston-type cylindrical damper, the main air chamber, the sub-air chamber, and both the main and sub-air chambers. An air suspension device comprising a passage and means for changing the opening area of the passage, the spring constant being changed by changing the opening area of the passage,
In order to elastically support the piston rod of the cylindrical damper on the vehicle body, the upper and lower surfaces are held by a pair of rod bushes fitted to the tip of the piston rod, and the piston rod is inserted into the center hole thereof. A mounting bracket is provided,
The main and auxiliary air chambers are arranged approximately concentrically with respect to the piston rod, and an air space is formed between the inner surface of the center hole of the mount bracket and the opposing end surfaces of the upper and lower rod bushes. A passage communicating with the main air chamber is formed in the piston rod, and a passage communicating between the air chamber and the auxiliary air chamber is formed in the radial direction between the mount bracket and both the main and auxiliary air chambers. This is achieved by providing an air suspension device characterized in that it is formed between a separating cylinder. In particular, one of the rod bushes disposed above the mount bracket may be fixed by baking to the outer peripheral surface of the member constituting the piston rod and the upper surface of the mount bracket.

<Operation> In this way, both the main and sub-air chambers can communicate with each other via the passage formed in the piston rod and the passage formed between the mount bracket and the cylindrical body. In the case of this structure, since the rod bush itself does not require any special processing, it can be made into a homogeneous shape, which is advantageous in setting the capacity of the bush.

Further, by fixing the rod bush by baking, it is possible to ensure airtightness of the communication passage without using a separate sealing material.

<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 FIG. 1, the left side indicates the upper side, and the explanation will be made in accordance with the direction shown in the figure.

In this suspension device, an oil damper 1 is provided at the shaft center, the lower end of a cylinder 2 forming the outer shell of the damper is on the axle side, and a piston rod 3 is provided so as to be freely retractable from the cylinder 2. Each can be attached to the vehicle body 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 that slides inside the cylinder 2. A mount bracket 6 is attached on both upper and lower surfaces between a pair of rod bushes 4 and 5 that are fitted onto the outer peripheral surface of the rod.

The mount bracket 6 includes a bottomed cylindrical portion 6a formed to receive the lower rod bush 4;
The cylindrical portion 6a has a flange portion 6b formed radially outward at the lower open end thereof, and the piston rod 3 is loosely received in an insertion hole 6c formed at the bottom of the cylindrical portion 6a. It is attached to the vehicle body by stud bolts 7 planted in the flange portion 6b.

The inner peripheral surface of the cylindrical portion 6a and the lower rod bush 4
An upper cylindrical body 8 whose diameter is slightly enlarged toward the bottom is fixed between the outer circumferential surface of the upper cylinder and the outer circumferential surface of the upper cylinder.

A stopper 10 is attached to the outer periphery of the piston rod 3 facing the inner periphery of the upper cylinder 8 with a spacer 9 interposed between it and the lower surface of the lower rod bush 4. The contraction limit of the relative stroke between the cylinder 2 and the piston rod 3 is defined by the contact between the lower surface of the stopper 10 and the upper end surface of the cylinder 2.

The lower end of the upper cylindrical body 8 is placed on a surface substantially equal to the lower surface of the stopper 10, and a rolling bladder 11 formed in a cylindrical shape from an elastic material such as synthetic rubber is provided on the outer circumferential surface of this lower end. The upper open end of the lower cylindrical body 12 is fitted onto the outer peripheral surface of the rolling bladder 11 . As described above, the rolling bladder 11 is sandwiched between the upper cylinder 8 and the lower cylinder 12, and the upper end of the lower cylinder 12 is plastically deformed inward in the radial direction. Person 8,
11 and 12 are integrally and airtightly fixed.

The intermediate portion of the rolling bladder 11 is inverted inward, and its lower end portion is adhered to the outer circumferential surface of a holder portion 13 formed on the outer circumference of the cylinder 2.

In this way, the upper and lower cylindrical bodies 8 and 12 and the rolling bladder 12 form a main air chamber 14 that surrounds the upper part of the damper 1. The compression resistance force of the air sealed in this main air chamber 14 is
It acts as a spring that supports the force that tries to compress the piston rod 3 and cylinder 2, that is, the load between the axle and the vehicle body.

The upper end of an external cylinder 15 is fixed to the outer peripheral surface of the flange portion 6b of the mount bracket 6. The outer cylindrical body 15 has an annular liner 16 made of the same material as the rolling bladder 11 between the inner circumferential surface of its lower end and the outer circumferential surface of the lower cylindrical body 12. The bodies 8 and 12 are integrated in a hermetically sealed manner in the same manner as the joint portion.

As a result, a sub-air chamber 17 surrounding the main air chamber 14 is defined.

As shown in FIG. 2, the portion of the piston rod 3 above the stopper 10 has a reduced diameter shaft portion 20 and a hollow cylindrical shape that is in close contact with the shaft portion 20 and is rotatable. The piston rod 3 is made up of a rotary valve 21 and an outer tube 22 which is integrated with the piston rod 3 via a spacer 9 to receive the rotary valve 21. The upper and lower rod bushes 4 and 5 described above are fitted onto the outer peripheral surface of the outer tube 22.

Note that the lower rod bush 4 is sandwiched between a mount bracket 6 and a spacer 9, and is attached to the piston rod 3.
Since the vehicle load is received through the rod, sufficient airtightness can be obtained only by deformation due to the load. However, since the upper rod bush 5 is not normally subjected to loads such as rod reaction force, the contact surface with metal The baking process ensures the airtightness of the air passages, which will be described later.

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). By rotating this control rod 23 with an actuator 24 provided at the upper end of the piston rod 3,
The diameter of the orifice that communicates between the front and rear of the damper piston is changed, thereby making it possible to change the damping force.

At the top of the piston rod 3, a hydraulic pressure related passage 25 and an air supply/discharge passage 26 are formed, and an actuator 27 for controlling a rotary valve 21 for switching the air passage is attached to a block 2.
8 is fitted. This block 28 is prevented from coming off by a nut 28a screwed onto the end of the piston rod 3.

The hydraulic pressure related passage 25 is connected to the control rod 23
It communicates with the oil chamber inside the cylinder 2 through a center hole 29 through which it is inserted. This hydraulic pressure related passage 25 is
It is interconnected with the damper of each wheel with separate piping,
The operation of each wheel can be controlled in relation to each other, thereby further improving the stability of the vehicle body.

The air suction and discharge passage 26 communicates with the main air chamber 14 via a through hole 30 formed in the rotary valve 21 and a passage 31 formed on the outer peripheral surface of the shaft portion 20, and is connected to the main air chamber 14 via a separate solenoid valve. It is connected to a compressed air supply source via piping.

Passages 32 and 33 are formed between the inner surface of the bottom wall and the inner surface of the peripheral wall of the mount bracket 6 and the upper cylindrical body 8. And both upper and lower rod bushes 4,5
The rotary valve 21 and the outer tube 22 are located at positions corresponding to the gap C formed between the opposing surfaces at the center of the rotary valve 21 and the inner peripheral surface of the insertion hole 6c of the mount bracket 6 held between the upper and lower rod bushes 4 and 5. The main air chamber 14 and the sub-air chamber 17 can communicate with each other via through holes 34 and 35 bored through the shaft portion 20 and a passage 31 formed on the outer periphery of the shaft portion 20. Since both the rod bushes 4 and 5 are baked and fixed to the outer tube 22, airtightness of these passages can be ensured without using a separate sealing material.

As shown in FIG. 3, a slit 36 is cut in the upper part of the rotary valve 21 and extends along the axial direction of the piston rod 3. A connecting pin 37 that protrudes in the axial direction is engaged with the shaft end of the shaft.

The connection pin 37 is connected to the rotary actuator 27
The rotary valve 21 is eccentric with respect to the rotating shaft 27a, so that when the rotating shaft 27a is rotated, the rotary valve 21 rotates within a certain angular range.

On the other hand, the relationship between the through hole 34 of the rotary valve 21 and the through hole 35 of the outer tube 22 changes from a state where the openings align with each other as the rotary valve 21 rotates, to a state where one opening and the peripheral wall of the other completely align with each other. The rotation angle and hole diameter are determined so that the opening area A between the two through holes 34 and 35 can be changed by rotating the rotating shaft 27a in one direction. has been done.

Next, the procedure for assembling the rolling bladder 11 of the above embodiment will be explained.

First, the upper end of the rolling bladder 11 is sandwiched between the upper cylinder 8 and the lower cylinder 12, and then the upper end of the lower cylinder 12 is caulked inward. Next, the mount bracket 6 to which the upper end of the outer cylinder 15 is fixed is fitted onto the upper end of the upper cylinder 8 from above. Then, the lower cylindrical body 12 and the lower end of the outer cylindrical body 15 are overlapped with each other via the liner 16, and the lower end 15a of the outer cylindrical body 15 is caulked inward. Note that reinforcing members 12b and 15b are provided at the caulked portions, respectively, so that they can withstand inward stress.

The lower end of the rolling bladder 11 is bonded in advance to the holder portion 13 of the cylinder 2, but this portion is tightly fixed by the action of the elasticity and air pressure of the rolling bladder itself, similar to the bead portion of a vehicle tire. It's okay to be.

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

In air springs, the spring constant varies with the volume of the air chamber relative to the stroke. Here, the through hole 34 of the rotary valve 21 and the through hole 3 of the outer tube 22
5, the spring constant becomes high because only the volume of the main air chamber 14 acts, and both the communication holes 3
When the communication between air chambers 4 and 35 is fully opened, the main air chamber 14 and the sub air chamber 17 communicate with each other via the passage 31 of the shaft portion 20 and the passages 32 and 33 of the mount bracket 6. The combined volume acts to lower the spring constant. Therefore, both air chambers 14,1
By changing the opening area A of the through holes 34 and 35 in the communicating state of No. 7, the spring constant can be arbitrarily set.

Further, by letting compressed air in and out through the air suction and discharge passage, the internal pressure of the air chamber can be adjusted, and an appropriate spring constant can be obtained at all times in response to fluctuations in the sprung 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, it becomes possible to form a communication passage between the main air chamber and the sub-air chamber extremely easily, and this is a great advantage in simplifying the structure and reducing manufacturing costs. effective.

Further, as shown in the above embodiment, if the cross-sectional area of the communication passage is adjusted by a rotary valve provided on the outer periphery of the piston rod, further compactness can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of essential parts of an air suspension device based on the present invention. FIG. 2 is a partially enlarged sectional view of the air suspension device shown in FIG. 1. FIG. 3 is a perspective view conceptually showing the structure of the rotary valve. 1...Oil damper, 2...Cylinder, 3...
Piston rod, 4... Upper rod bush, 5
... Lower rod bush, 6 ... Mount bracket, 6a ... Cylindrical part, 6b ... Flange part, 6c ... Insertion hole, 7 ... Stud bolt, 8
... Upper cylinder, 9 ... Spacer, 10 ... Stopper, 11 ... Rolling bladder, 12 ... Lower cylinder, 12a ... Upper end, 12b ... Reinforcement member, 1
3...Holder portion, 14...Main air chamber, 15...Outer cylinder, 15a...Lower end portion, 15b...Reinforcement member, 16...Liner, 17...Sub-air chamber, 20...
...Shaft portion, 21...Rotary valve, 22...Outer tube, 23...Control rod, 24
... Actuator, 25 ... Hydraulic related passage, 2
6... Air suction and exhaust passage, 27... Actuator.

Claims (1)

[Claims for Utility Model Registration] (1) A piston-type cylindrical damper, a main air chamber, a sub-air chamber, a passage communicating between the main and sub-air chambers, and means for varying the opening area of the passage. An air suspension device having a spring constant that changes by changing the opening area of the passage, wherein the piston rod 3 of the cylindrical damper 1 is elastically supported on the vehicle body; a pair of rod bushes 4, 5 fitted to the tip of the piston rod;
A mount bracket 6 is provided, the upper and lower surfaces of which are clamped by a mount bracket 6, into which the piston rod is inserted, and the main and auxiliary air chambers 14, 17 are approximately concentric with respect to the piston rod. A passage 31 is provided in the piston rod and communicates between the main air chamber and a cavity C defined between the inner surface of the center hole of the mount bracket and the opposing end surfaces of the upper and lower rod bushings. passages 32 and 33 communicating between the air chamber and the sub-air chamber are formed between the mount bracket and the cylindrical body 8 that radially separates the main and sub-air chambers; An air suspension device featuring: (2) A utility model characterized in that one side 5 of the rod bushing arranged above the mount bracket is fixed by baking to the outer peripheral surface of the member constituting the piston rod and the upper surface of the mount bracket. An air suspension device according to claim 1.