JPS6346908A - Suspension device for vehicle - Google Patents

Abstract

PURPOSE:To reduce weight and shorten an oil passage and aim at restricting increase of a dynamic spring constant in a suspension device including more than one gas chambers for vehicles by separating its outer cylinder with parting members and providing more than one of the gas chambers inside the outer cylinder. CONSTITUTION:When an inner cylinder 6 moves down to an outer cylinder 5, part of oil an oil chamber 24 flows through a constant orifice 30 and a changeable orifice 31 into an oil chamber 26, producing a damping force, while at the same time bellows 20 is extended, reducing the volume of a gas chamber 23. If an opening/closing valve 58 is open at this time, part of oil in oil chambers 24, 27 flows into a sub-chamber 3, while bellows 48 in the sub-chamber 3 extend to reduce the volume of a gas chamber 50. If the opening/closing valve 58 is closed, the sub-chamber 3 does not operate, but only a main actuator 2 operates. With this constitution, reduction of weight, shortening of an oil passage, and restriction on increase of a dynamic spring constant can be aimed at.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vehicle suspension system used in a suspension mechanism of an automobile or the like.

[Conventional technology]

2. Description of the Related Art Suspension systems known as so-called hydropneumatic suspensions are known in which the spring constant can be changed over two or more stages. A conventional suspension system of this kind has two or more sub-chambers that communicate with the inside of the main actuator via oil passages on the outside of a main actuator that has a built-in oil chamber, and a gas chamber inside each of the sub-chambers. It is set up. By opening and closing or directionally controlling the oil passages connecting the main actuator and each sub-chamber using valves, the effective gas chamber volume acting as a gas spring is changed and the spring constant is switched.

[Problem that the invention seeks to solve]

However, in the suspension system having the above structure, the number of sub-chambers corresponding to the number of switching stages of the spring constant is required outside the main actuator, and therefore the volume and external size are quite large. Furthermore, the pipe lines connecting each sub-chamber become long, which causes problems such as an increase in the dynamic spring constant.

[Means for solving problems]

The present invention includes a main actuator that includes an outer cylinder and an inner cylinder or solid rod that is inserted into the outer cylinder so as to be able to reciprocate in the axial direction, and has an oil chamber inside, and a main actuator that is attached to the outside of the main actuator and has an oil chamber inside. For vehicles equipped with a sub-chamber communicating with the internal oil chamber of the actuator, and further incorporating two or more gas chambers whose volume changes with the relative reciprocation between the outer cylinder and the inner cylinder or the solid rod. Applies to suspension systems.

In the present invention, the inside of the outer cylinder is partitioned by a partition member such as a bellows, a bladder, a free piston, etc., and at least one of the two or more gas chambers is partitioned by the partition member. It is characterized by being provided inside the outer cylinder.

[Effect]

In the vehicle suspension system configured as described above, at least one of the two or more gas chambers required to switch the spring constant to two or more stages is built into the main actuator, so the pressure-resistant outer walls of the main actuator and the gas chamber are can be shared. Therefore, not only the weight can be reduced, but also the oil passage etc. can be shortened, and an increase in the dynamic spring constant can be suppressed. In addition, the external shape is compact, making it easier to secure space for installation on the vehicle body.

〔Example〕

The vehicle suspension system 1 shown in FIG. 1 includes a main actuator 2 and a subchamber 3. The main actuator 2 has an outer cylinder 5 having a double wall structure and an inner cylinder 6 inserted into the outer cylinder 5 so as to be able to reciprocate in the axial direction.

More specifically, the outer cylinder 5 includes a first cylinder located on the upper side in the figure.
The first member 7a is configured to include an outer wall portion 7 consisting of a member 7a and a second member 7b located below, and an inner wall portion 8 disposed inside concentrically with the outer wall portion 7. and the second member 7b are connected to each other by an intermediate member 9. Further, an end member 10 is fixed to the upper end of the first member 7a in the drawing, and an end plate 11 is provided to the lower end of the second member 7b. A connecting eye member 13 is attached to this end plate 11. This eyepiece member 13 is connected, for example, to a member (not shown) on the wheel side of an automobile. Further, the intermediate member 9 is provided with a gas filling port 14.
It is designed to be closed by a blind stopper 15. The end member 10 is provided with a dust seal 17, a bearing 18, a high pressure seal 19, and the like.

Further, a metal bellows 20, which is an example of a partition system, is provided between the second member 7b and the inner wall part 8 so as to be expandable and contractible in the axial direction, and partitions the inside of the outer cylinder 5 into two parts. ing. The upper end of this bellows 20 is airtightly fixed to the intermediate member 9 by welding or the like. A lid 21 is airtightly attached to the lower end of the bellows 20. The lid 21 moves up and down as the bellows 20 expands and contracts, and comes into contact with and away from the lower end opening 8a of the inner wall portion 8. The first gas chamber 23 formed between the bellows 20 and the outer wall 7 is filled with an inert gas such as nitrogen gas at high pressure. The inner portion defined by the bellows 20 and the lid 21 is filled with a pore and is used as the first oil chamber 24.

On the other hand, the inner cylinder 6 is inserted into the outer cylinder 5 so as to be able to reciprocate in the axial direction. An oil chamber 26 is formed between the inner cylinder 6 and the inner wall 8, and an oil chamber 27 is also formed inside the inner cylinder 6.

A piston portion 29 for generating damping force is provided at the tip (lower end side in the drawing) of the inner cylinder 6. The outer circumferential surface of the piston portion 29 is in sliding contact with the inner circumferential surface of the inner wall portion 8, and serves to stabilize the vertical movement of the inner cylinder 6.

The piston portion 29 is provided with a constant orifice 30 using a well-known plate valve or the like, and a variable orifice 31 whose flow path cross-sectional area can be variably set. The oil chamber 24 is then
and the oil chamber 26, and between the oil chamber 24 and the oil chamber 27. That is, the variable orifice 31 is
The rotary valve body 33 is rotated by a drive source 32 using a motor or a solenoid, and the cross-sectional area of the flow path is changed by switching the rotational position of the second valve body 33 to two or more stages. It is. The drive source 32 is housed in the internal space of the inner cylinder 6. In addition, the variable orifice 3
1 allows the aforementioned oil chambers 24°, 26, and 27 to communicate with each other via an oil passage 36 formed inside the cylindrical body 35.

A cable 37 that supplies power to the drive source 32 is inserted into the inner cylinder 6, and the gap is filled with a sealing material 38 such as synthetic resin.

Further, a bump rubber 40, a dust cover 41, a sub-chamber mounting base 42, etc. are attached to the upper end of the inner cylinder 6 in the drawing, and a mount insulator 43 is fixed to a portion connected to the vehicle body. A part 42a of the base 42 extends in the horizontal direction in the figure, and the subchamber 3 is attached to this part 42a.

The subchamber 3 includes a cylindrical container 46 and an inner cylinder portion 47 arranged concentrically inside the container 46. A metal bellows 48 is provided between the container 46 and the inner cylindrical portion 47 so as to be freely expandable and contractible in the axial direction.
The interior of the container 46 is divided into a second gas chamber 50 and an oil chamber 51. The gas chamber 50 is filled with an inert gas such as nitrogen gas under high pressure. The upper end of the '-2 bellows 48 is airtightly fixed to a member 53 on the base 42 side by welding or the like. A lid 55 is airtightly attached to the lower end of the bellows 48. This lid 55 moves up and down with the expansion and contraction of the bellows 48, and the lower end opening 47 of the inner cylinder portion 47
It is designed to come into contact with and separate from a.

The oil chamber 51 and the oil chamber 27 of the inner cylinder 6 described above are connected by an oil passage 56, and this oil passage 56 is opened and closed by an on-off valve 58 for changing a spring constant. This on-off valve 58
is adapted to be driven by a drive source 59 such as a solenoid housed in the subchamber 3.

Next, the operation of the vehicle suspension system 1 having the above configuration will be explained.

If the inner cylinder 6 moves, for example, downward in the figure with respect to the outer cylinder 5, a part of the oil in the oil chamber 24 flows into the oil chamber 26 side through the constant orifice 30 and the variable orifice 31, and a damping force is generated. At the same time, the bellows 20 expands as shown by the imaginary line, causing the gas chamber 2 to
The volume of 3 decreases. At this time, the on-off valve 5 in the subchamber
8 is opened, a part of the oil in the oil chamber 24.27 flows to the subchamber 3 side through the oil passage 56, and the bellows 48 in the subchamber expands, causing the oil in the second gas chamber 50 to flow.
The volume of decreases. On the other hand, if the on-off valve 58 is closed,
Since the oil passage 56 is blocked, the subchamber 3 does not function, and only the bellows 20 of the main actuator 2 extends.

Conversely, when the inner cylinder 6 moves in the extension direction with respect to the outer cylinder 5, part of the oil in the oil chamber 26 flows through the constant orifice 30 and the variable orifice 31 into the oil chamber 24.
At the same time, the bellows 20 contracts (rises) and the volume of the gas chamber 23 increases. At this time, if the on-off valve 58 is opened, part of the oil in the oil chamber 51 of the sub-chamber 3 flows toward the main actuator 2 through the oil path 56, and the bellows 48 of the sub-chamber also contracts (rises). However, the volume of the second gas chamber 50 increases.

That is, in the above configuration, when the on-off valve 58 is closed, only the gas chamber 23 of the main actuator 2 effectively works as a gas spring, so the spring constant increases; Since the two gas chambers 23.50 cooperate as a gas spring, the effective gas volume increases and the spring constant decreases.

In addition, by operating the drive source 32 for the variable orifice and switching the flow path cross-sectional area of the variable orifice 31,
It is also possible to select the magnitude of the damping force. For example, when driving on a rough road, making a sharp turn, or braking suddenly, the posture of the vehicle body can be stabilized by controlling the spring constant and damping force to increase both. Furthermore, when driving on a good road, both the spring constant and the damping force can be reduced to improve riding comfort. The above-mentioned road surface conditions and vehicle body conditions are detected by sensors installed on the vehicle body, etc., and the driving R32
, 59 may be automatically controlled, or the drive source 32.59 may be controlled manually using a manual switch. In addition, the vehicle height can be adjusted using the oil chambers 24, 26, 27,
51. This may be done by providing an oil boat communicating with the outside in any one of the oil passages 56 and the like, and supplying and withdrawing oil therefrom.

Note that by providing two or more sub-chambers 3, the spring constant may be switched in three or more stages.

FIG. 2 shows another embodiment of the present invention. In this case, the sub-chamber 3 is attached to the outer cylinder 5, and the oil chamber 24 of the main actuator 2 and the oil of the sub-chamber 3 are connected via an oil passage 56. The chambers 51 are communicated with each other. Other basic configurations and functions and effects are the same as those of the embodiment shown in FIG.

〔Effect of the invention〕

According to the present invention, at least one of the two or more gas chambers required to switch the spring constant to two or more stages is built into the main actuator, so the outer wall, which is required to be pressure resistant and inevitably becomes heavy, can be saved. It can be shared between the main actuator and the gas chamber.

Therefore, not only the weight can be reduced, but also the oil passage etc. can be shortened, and an increase in the dynamic spring constant can be suppressed. The external shape is also made more compact.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a vehicle suspension system showing one embodiment of the invention, and FIG. 2 is a longitudinal sectional view showing another embodiment of the invention. 1... Vehicle suspension system, 2... Main actuator,
3...Subchamber, 5...Outer cylinder, 6...Inner cylinder, 2
0... Bellows (partition member), 23... First gas chamber, 24.26.27... Oil chamber, 50... Second gas chamber, 51... Oil chamber. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (1)

[Claims] A main actuator that includes an outer cylinder and an inner cylinder or solid rod that is inserted into the outer cylinder so as to be able to reciprocate in the axial direction and has an oil chamber inside, and a main actuator that is attached to the outside of the main actuator and has an internal oil chamber. A sub-chamber that communicates with the chamber, and a volume that changes with relative reciprocation between the outer cylinder and the inner cylinder or the solid rod.
In a vehicle suspension system incorporating two or more gas chambers, the inside of the outer cylinder is partitioned by a partition member, and at least one of the two or more gas chambers is arranged inside the outer cylinder partitioned by the partition member. A vehicle suspension system characterized by being provided with.