JPH11117977A - Suspension cylinder for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of the damage of a diaphragm during zero-down of a suspension cylinder, used in a hydro-pneumatic suspension, through simple constitution. SOLUTION: In a suspension cylinder 1 for a vehicle wherein a space between a cylinder 4 and an outer shell 21 is partitioned into an oil chamber 23 and a gas chamber 24 by a diaphragm 22, the two ends of the diaphragm are securely and respectively nipped between an outer shell 21 and a bearing 5 arranged on the outer shell 21 side or the cylinder 4 side and a part 5, extending from the fixing parts 16 and 17 of the diaphragm 22 to the outer wall surface of a cylinder 4 and a bottom case 9 part, is formed as gentle taper surfaces 18 and 19 and oil passages 25 and 26 communicated with the internal part of the cylinder 4 are opened to the taper surface 19 part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension cylinder used for a hydropneumatic suspension for suspending a vehicle, and more particularly, to a suspension cylinder having a vehicle height adjusting function in addition to a spring action and a damping action. Suspension cylinders for vehicles.

[0002]

2. Description of the Related Art Conventionally, this type of vehicle suspension cylinder has
For example, as shown in JP-A-48-50175, a diaphragm is disposed in a gap between a cylinder and an outer shell, and both ends of the diaphragm are fixed to the cylinder or the outer shell. It is properly fixed by being sandwiched between a bearing provided in the cylinder and a bottom case.

[0003] The above-mentioned diaphragm divides a gap between the cylinder and the outer shell into an oil chamber and a gas chamber, and the oil chamber is passed through an oil passage provided in a cylinder, a bearing or a bottom case. And a hydraulic oil chamber in this cylinder is connected to a control hydraulic circuit through a leveling oil passage provided in a piston rod.

[0004]

However, in this type of suspension cylinder for a vehicle, the leveling oil passage of the piston rod is separated from the hydraulic circuit for control, such as before the vehicle is mounted on or removed from the vehicle. In a state where the oil pressure is released, that is, in a zero down state, the diaphragm is bulged inward by the high-pressure gas in the gas chamber, and the hydraulic oil in the oil chamber is pushed out from the oil passage to the hydraulic oil chamber of the cylinder.

As a result, the diaphragm is pressed against the outer shell or the cylinder or the wall surface of the bearing or the bottom case by bulging inward, thereby closing the oil passage and keeping the oil chamber in a sealed state, and the leveling oil passage of the piston rod. Of hydraulic oil leaking from the outside to the outside.

Therefore, it is desirable that the diaphragm be made of a flexible elastic material such as rubber so that the change in the volume of the oil chamber and the blockage of the oil passage can be ensured.

Nevertheless, the diaphragm is
Not only does the high-pressure gas in the gas chamber inflate and inflates the oil path described above, but also the mounting portion at both ends is bent extremely and pushed into the fitting gap between the cylinder and the bearing or the bottom case.

[0008] For this reason, there is a possibility that damage may occur at this point of the diaphragm, and the high-pressure gas in the gas chamber may be blown out to the outside through the leveling oil passage of the piston rod together with the hydraulic oil in the cylinder.

In addition, when the leveling oil passage of the piston rod is connected to a hydraulic circuit for control and used, when the body load is removed by jacking up, the hydraulic oil pressure in the oil chamber becomes zero. As a result, the diaphragm enters a zero down state.

In addition, even in the case where the height of the vehicle body is reduced to an extremely low vehicle height in the above-mentioned use condition, a large amount of hydraulic oil in the cylinder is transferred to the reservoir in the hydraulic circuit for control. Returning, the diaphragm is also in the state of zero down.

In addition, the above-mentioned jack-up is performed at a relatively high frequency depending on the condition of the vehicle and the like. Particularly, the extremely low vehicle height is often very high depending on the condition of the running road surface and the running conditions. Done.

As a result, the diaphragm is easily damaged by repeating the zero-down state, and when the diaphragm is damaged, the high-pressure gas in the gas chamber leaks to the oil chamber through the diaphragm, and mixes with the hydraulic oil in the oil chamber to increase the vehicle height. Moves into the hydraulic oil chamber of the cylinder with the raising and lowering operation of the cylinder.

[0013] Then, by repeating the supply / discharge operation of the hydraulic oil by raising and lowering the vehicle height, all the high-pressure gas in the gas chamber is discharged to the reservoir in the hydraulic circuit for control and released to the atmosphere, and the inside of the cylinder and the outer shell is released. There was a disadvantage that the original function as the suspension cylinder could not be performed due to only the hydraulic oil.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a suspension cylinder used for a hydropneumatic suspension for suspending a vehicle, which can prevent damage to the diaphragm during zero down by a simple configuration. .

[0015]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a suspension cylinder for a vehicle, in which a diaphragm is partitioned into an oil chamber and a gas chamber by a diaphragm between a cylinder and an outer shell. The bearing and bottom case are provided between the fixed part of the diaphragm and the outer case of the cylinder. This is achieved by opening an oil passage leading to the interior of the cylinder.

That is, with the above-described configuration, the diaphragm is pushed inward by the expansion of the high-pressure gas in the gas chamber and inwardly regardless of before and after the vehicle is attached to the vehicle, even in the case of zero down in any case. When it comes out, it does not bend extremely at the end mounting parts, but gently swells from the tapered surfaces of the bearing and the bottom case to the outer wall surface of the cylinder, and the diaphragm makes the hydraulic oil chamber in the cylinder and the oil in the accumulator. Block the oil passage connecting the chambers.

[0017] Therefore, not only is there little local deformation occurring in the diaphragm, the durability is excellent, but also there is no danger that the mounting portions at both ends of the diaphragm are pushed into the fitting gap between the cylinder and the bearing or the bottom case to be damaged. This prevents the high pressure gas in the gas chamber from leaking through the diaphragm to the oil chamber.

As a result, the high-pressure gas in the gas chamber blows out to the outside through the leveling oil passage of the piston rod together with the hydraulic oil in the cylinder, or all of the high-pressure gas is discharged to the reservoir in the hydraulic circuit for control. The possibility that the original function as a suspension cylinder cannot be achieved is also eliminated.

Preferably, in addition to the above, a frusto-conical check valve that covers the oil passage while being bent by being pressed by the diaphragm is disposed opposite to the oil passage that opens to the tapered surface of the bottom case.

Accordingly, the check valve is pushed by the inward bulging of the diaphragm to close the oil passage, so that the check valve is also prevented from getting into the oil passage and being damaged, and thus each of the above-described valves is prevented. The fear can be more reliably removed.

Further, in addition to these, the outer wall surface of the outer shell between the fixed portions at both ends of the diaphragm is bulged outward to achieve a more preferable form.

What is required is that, when assembling the suspension cylinder for a vehicle, necessary members such as a piston rod and a diaphragm are assembled in advance to the cylinder, and this is inserted into the outer shell to assemble the cylinder to improve workability. Because it can be.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view of a vehicle suspension cylinder 1 according to an embodiment of the present invention. The vehicle suspension cylinder 1 is shown by a leveling oil passage 3 provided in a piston rod 2. Not tied to the control hydraulic circuit.

The piston rod 2 penetrates a bearing 5 provided over one end of the cylinder 4 and extends into the cylinder 4 while maintaining an oil-tight state by a seal 6, and the inner end guides the inner wall of the cylinder 4. And is connected to a piston 7 that slides with a piston nut 8.

The other end of the cylinder 4 is closed by a bottom case 9 provided so as to cover the relevant portion, and the inside of the cylinder 4 is connected to the hydraulic oil chambers 10 and 11 by the piston 7 in cooperation with the bearing 5 described above. A leveling oil passage 3 penetrating through the piston rod 2 communicates with the working oil chamber 11.

The hydraulic oil chambers 10 and 11 communicate with each other through two sets of ports 12 and 13 formed in the piston 7, and the opening end of one of the sets of ports 12 to the hydraulic oil chamber 11 is extended. While the damping valve 14 is closed, the open ends of the other group of the port groups 13 to the hydraulic oil chamber 10 are closed by the pressure-side damping valves 15.

The bearing 5 and the bottom case 9 are
The outer part on the opposite side of the mounting part to the cylinder 4 has a large diameter,
By forming an annular groove in that part, the fixing part 16,
17, and a portion extending from these fixing portions 16 and 17 to the outer wall surface of the cylinder 4 has a gentle tapered surface 18,
19 is formed.

On the outer periphery of the cylinder 4, fixed portions 16, 17
An outer shell 21 having a lower cap 20 at one end is provided with an air gap between the outer shell 21 and the outer shell 21, and the diaphragm 2 is fixed by the fixing portions 16 and 17 and the outer shell 21.
By sandwiching and fixing both ends of 2, the gap between the cylinder 4 and the outer shell 21 is partitioned into an oil chamber 23 and a gas chamber 24 by the diaphragm 22.

By fixing both ends of the diaphragm 22 between the fixing portions 16 and 17 and the outer shell 21 in this manner, the hydraulic oil and the gas chamber 24 in the oil chamber 23 at the bearing 5 and the bottom case 9 are provided. The high pressure gas inside is leaked to the outside and the one leaking and mixing with the other is sealed and sealed.

The oil chamber 23 has an annular oil passage 25 provided between the cylinder 4 and the bottom case 9, and also extends from between the cylinder 4 and the bottom case 9 to the inner bottom of the bottom case 9. It communicates with the hydraulic oil chamber 11 inside the cylinder 4 through the plurality of oil passages 26 formed in a concave groove shape.

As a result, the opening of the oil passage 25 with respect to the oil chamber 23 is formed by a slight gap located at the boundary portion from the tapered surface 19 of the bottom case 9 to the outer wall surface of the cylinder 4.

However, even so, this oil passage 25
The opening to the oil chamber 23 can have a large overall length by surrounding the outer wall surface of the cylinder 4, so that a sufficient flow path area can be secured.

On the other hand, the outer shell 21 has a gas supply port 2 for introducing high-pressure gas into the gas chamber 24.
After the high-pressure gas is introduced from the gas supply port 27 into the gas chamber 24, the gas supply port 27 is closed with a sealing plug 28 so that the high-pressure gas at a predetermined pressure can be sealed. It is.

On the other hand, when assembling the suspension cylinder 1 for a vehicle, the piston rod 2 having the piston 7 is inserted into the cylinder 4 so that both ends are provided with the bearing 5 and the bottom case 9.
And the bearing 5 and the bottom case 9
The bottom case 9 is inserted to a position where the bottom case 9 comes into contact with the lower cap 20 of the outer shell 21 in a state where both ends of the diaphragm 22 are fitted between the fixing portions 16 and 17.

Thus, while fixing both ends of the diaphragm 22 between the fixing portions 16 and 17 and the inner wall surface of the outer shell 21, the packing case 30 having the packing 29 is screwed onto the outer shell 21 from above, and the lower cap 2
The bearing 5 and the bottom case 9 are assembled by sandwiching the bearing 5 with the packing case 30.

Therefore, in the present embodiment,
The outer portion of the outer shell 21 for fixing both ends of the diaphragm 22 is swelled outward, and when the cylinder 4 is inserted into the outer shell 21, it is easy to assemble while preventing both ends of the diaphragm 22 from being damaged at both ends. And the volume of the gas chamber 24 can be secured to a specified amount.

When a larger volume of the gas chamber 24 is required, a portion that does not hinder mounting on a vehicle, such as an upper portion of a spring seat 31 that supports one end of a suspension spring, is shown in FIG. What is necessary is just to bulge further outward as shown by the broken line.

In this manner, the cylinder 4 serves as a sliding guide for the piston 7 and also supports the diaphragm 22 in the axial direction, so that the high-pressure gas in the gas chamber 24 expands and the diaphragm 22 moves inward. An accumulator is formed in cooperation with the outer shell 21 while regulating the amount of swelling when swelling.

Thus, the vehicle suspension cylinder 1 according to the embodiment shown in FIG. 1 having the above-described structure is mounted on the vehicle wheel and the vehicle body through the mounting eye 32 provided on the lower cap 20 of the outer shell 21 and the protruding end of the piston rod 2. By using a suspension spring 33 interposed between the spring seat 31 and the vehicle body and using the suspension spring 33 between the spring seat 31 and the vehicle body, it operates as described below.

When the vehicle is running, the vibration generated between the vehicle body and the wheels gives a relative displacement between the cylinder 4 and the piston 7 through the piston rod 2 and the mounting eye 32 in the extension and compression directions.

During the extension operation, the hydraulic oil in the hydraulic oil chamber 10 flows from the port group 12 of the piston 7 to the hydraulic oil chamber 11 by pushing and opening the expansion damping valve 14. A predetermined extension-side damping force is generated by the flow resistance of the hydraulic oil when it flows by pushing and opening 14.

In addition to this, a sufficient amount of hydraulic oil corresponding to the integral of the piston rod 2 withdrawing from the cylinder 4 is discharged by the expansion of the gas chamber 24 to the diaphragm 22.
Is supplied from the oil chamber 23 to the hydraulic oil chamber 11 through the oil passages 25 and 26 while inflating inward, and the hydraulic oil compensates for the shortage with the hydraulic oil and suspends the gas spring action by the high-pressure gas in the gas chamber 24. The vehicle body is supported by the spring force of the spring 33.

During the compression operation, the hydraulic oil chamber 1
The hydraulic oil in 1 is extruded from the oil passages 25 and 26 to the oil chamber 23 by expanding the diaphragm 22 outward to compress the high-pressure gas in the gas chamber 24 while increasing the gas pressure and to the oil chamber 23. Then, the hydraulic oil is pushed out to absorb the surplus hydraulic oil in an amount corresponding to the volume integral of the piston rod 2 entering the cylinder 4.

In addition, in parallel with this, the hydraulic oil in the hydraulic oil chamber 11 is opened and pushed from the port group 13 of the piston 7 to the hydraulic oil chamber 10 by opening and opening the pressure-side damping valve 15. The gas chamber 24 generates a predetermined pressure-side damping force due to the flow resistance of the hydraulic oil when it opens and flows.
The vehicle body is supported by the gas spring action by the gas pressure and the spring force of the suspension spring 33.

Thus, the vehicle suspension cylinder 1 expands and contracts with the vibration between the vehicle body and the wheels during running of the vehicle, and the expansion side and compression side damping valves 14 and 15 respectively provide a predetermined expansion side damping force and compression side damping force. While generating a force and expanding and compressing the gas chamber 24 by the retraction and ingress of the piston rod 2 with respect to the cylinder 4, the gas spring action by the gas pressure of the gas chamber 24 and the spring force of the suspension spring 33 adjust the body. I will support you.

On the other hand, when the hydraulic oil is sent from the hydraulic circuit for control to the hydraulic oil chamber 11 of the cylinder 4 through the leveling oil passage 3 of the piston rod 2 during the leveling operation of the vehicle height, the hydraulic oil is The oil flows into the oil chamber 23 between the cylinder 4 and the outer shell 21 through the oil passages 25 and 26.

The hydraulic oil that has flowed into the oil chamber 23 causes the diaphragm 22 to bulge outward and contract the gas chamber 24,
The gas spring action by the gas chamber 24 is increased to increase the hydraulic oil pressure in the hydraulic oil chamber 11 and the oil chamber 23.

Thus, the piston rod 2 pushes out the hydraulic oil in the hydraulic oil chamber 10 from the port group 12 in the piston 7, pushes the extension-side damping valve 14 open and pushes the hydraulic oil into the hydraulic oil chamber 11, and exits from the cylinder 4. And increases the vehicle height in accordance with the amount of hydraulic oil sent from the control hydraulic circuit.

Conversely, if the leveling oil passage 3 is communicated to the reservoir of the hydraulic circuit through the hydraulic circuit for control, the gas chamber 24 expands while the diaphragm 22 contracts, and the oil chamber 23 expands. The hydraulic oil in the tank is discharged from the oil passages 25 and 26 through the hydraulic oil chamber 11 and the leveling oil passage 3 to a reservoir of a hydraulic circuit for control.

As a result, in this case, the gas spring action of the gas chamber 24 decreases, and the hydraulic oil pressure in the hydraulic oil chamber 11 and the hydraulic chamber 23 decreases, and the piston rod 2 operates in the hydraulic oil chamber 11. The oil enters the cylinder 4 while opening the pressure side damping valve 15 from the port group 13 of the piston 7 and pushing the oil into the hydraulic oil chamber 10, and the vehicle is driven according to the amount of hydraulic oil discharged to the reservoir of the control hydraulic circuit. Lower the height.

In this manner, by selectively switching the communication of the leveling oil passage 3 by the control hydraulic circuit, the vehicle height can be freely adjusted to a desired height regardless of the stopped state and the running state. Can be adjusted.

On the other hand, when the suspension cylinder 1 for the vehicle is in a zero down state by jacking up, controlling the vehicle to an extremely low vehicle height, or removing the vehicle from the vehicle, the diaphragm 22
Is pushed by the expansion of the high-pressure gas in the gas chamber 24 and bulges inward, and is stuck to the outer wall surface of the cylinder 4.

In this case, regardless of whether the vehicle is mounted on the vehicle before or after the zero-down operation in any case, the mounting portions at both ends of the diaphragm 22 are not extremely bent, and the tapered surfaces 18 and 19 of the bearing 5 and the bottom case 9 are not bent. Swells gently inward along the outer wall surface of the cylinder 4,
The diaphragm 22 is guided by the tapered surfaces 18 and 19 to prevent the diaphragm 22 from being damaged.

In the above description, even if there are gaps between both end surfaces of the cylinder 4 and the fitting portions of the bearing 5 and the bottom case 9 and the diaphragm 22 tries to cut into these gaps, these gaps are formed by ordinary processing. The bite of the diaphragm 22 does not occur because it can be easily and very slightly controlled by the accuracy.

Although the diaphragm 22 may protrude into the oil passage 25 between the cylinder 4 and the bottom case 9, the oil passage 25 also surrounds the outer wall surface of the cylinder 4 as described above. Since the entire length of the diaphragm 22 can be increased, a sufficient space can be secured with a small gap, so that the diaphragm 22 can be prevented from protruding into the oil passage 25.

For this purpose, both ends of the diaphragm 22 are attached to the bearing 5 with respect to the cylinder 4 and the bottom case 9.
Of the high-pressure gas in the gas chamber 24 to the oil chamber 23 through the diaphragm 22 while preventing the high-pressure gas in the gas chamber 24 from leaking into the oil chamber 23. Closes the oil passage 25.

Accordingly, the high-pressure gas in the gas chamber 24 blows out through the leveling oil passage 3 of the piston rod 2 together with the hydraulic oil in the cylinder 4 to the outside, or
This also eliminates the risk that all of the high-pressure gas will be discharged to the reservoir in the hydraulic circuit for control and will not be able to function properly as a suspension cylinder.

FIGS. 2 and 3 are partially enlarged views showing another embodiment. In the case where it is necessary to increase the flow passage area of the oil passage 25 to some extent for design reasons. , FIG. 2
And as shown in FIG. 3, the tapered surface 1 of the bottom case 9
A truncated cone-shaped check valve 34 that covers the oil passage 26 while being bent by being pushed by the diaphragm 22 in opposition to the oil passage 26 opening to the nozzle 9 is arranged.

By doing so, the check valve 3
In the case 4, the portion on the inner diameter side normally floats up from the tapered surface 19 of the bottom case 9 as shown in FIG. 2 due to its own spring action, thereby ensuring communication with the oil chamber 23 of the oil passage 25.

On the other hand, at the time of zero down,
The diaphragm 22 is pushed by the high-pressure gas in the gas chamber 24 and bulges inward, and the check valve 34 is pushed by the diaphragm 22 to bend toward the tapered surface 19 of the bottom case 9.

Moreover, in this case, the check valve 34
Is slidably supported on the tapered surface 19 of the bottom case 9 and bends using the outer wall surface of the cylinder 4 as a guide surface, so that it is centered by the outer wall surface of the cylinder 4.

From this, the check valve 34 is set in advance.
By appropriately determining the inner diameter of the check valve 34 based on the outer diameter of the cylinder 4, the check valve 34 when bent can be used.
Covers and closes the oil passage 25 without generating a local large gap with the outer wall surface of the cylinder 4.

Since the check valve 34 is not fixed to either the cylinder 4 or the bottom case 9 as described above, the check valve 34 moves due to vibration or the like during running of the vehicle.

However, not only when the vehicle suspension cylinder 1 is removed, but also when the vehicle is at a standstill because the extremely low vehicle height or the jack-up causes a zero-down state when the vehicle is stopped, the check valve 34 is caused by vibration. It does not happen.

Even if the check valve 34 is deviated from the normal position due to vibration, the check valve 34 is kept at the normal position at zero down due to the support by the tapered surface 19 and the centering action by the outer wall surface of the cylinder 4.

In this way, it is possible to reliably prevent the diaphragm 22 from cutting into the oil passage 25 and being damaged at the time of zero down, so that the high-pressure gas is blown out together with the hydraulic oil to the outside, or all of the high-pressure gas is discharged. This effectively eliminates the fear that the oil is discharged to the reservoir in the control hydraulic circuit and cannot function properly as a suspension cylinder.

FIGS. 4 and 5 are partially enlarged views showing still another embodiment, similar to FIGS. 2 and 3 described above.
2 and 3, a check valve 34a is formed by radially forming a slit 35 from a portion on the reduced diameter side of the check valve 34.

The radial slit 35 can reduce the flexural rigidity of the check valve 34a.
Even if the flow path area of No. 5 is increased, the check valve 34
On the contrary, since the contact with the diaphragm 22 can be softened by easily bending without causing a problem in the strength of a, the effect of preventing the diaphragm 22 from being damaged can be further enhanced.

Further, in addition to this, check valve 3
An outer peripheral portion of 4a is sandwiched and fixed between the bottom case 9 and the outer shell 21 together with the diaphragm 22 to prevent the check valve 34a from being displaced from a proper position due to vibration.

In these respects, in addition to the effect of the check valve 34 shown in FIGS. 2 and 3 described above, not only the functional reliability can be further improved, but also the check valve 34a
Is elastically supported via the diaphragm 22, which also helps to reduce stress.

[0072]

As described above, according to the first aspect of the present invention, the diaphragm does not bend extremely at the two-end mounting portion regardless of whether the diaphragm is mounted before or after mounting to the vehicle. The tapered surface of the bearing and the bottom case gently swells from the tapered surface of the bottom case to the outer wall surface of the cylinder, and the diaphragm can close an oil passage communicating the hydraulic oil chamber in the cylinder and the oil chamber of the accumulator.

In addition, there is little local deformation that occurs in the diaphragm, and not only is the durability excellent, but also there is no danger that the mounting portion at both ends of the diaphragm is pushed into the fitting gap between the cylinder and the bearing or the bottom case and is damaged. It is also possible to prevent the high-pressure gas in the gas chamber in the accumulator from leaking through the diaphragm to the oil chamber.

As a result, the high-pressure gas in the gas chamber of the accumulator blows out together with the oil in the oil chamber and the hydraulic oil in the cylinder, or all of the high-pressure gas is discharged to the hydraulic circuit for control and serves as a suspension cylinder. It is also possible to eliminate the fear that the original function cannot be performed.

According to the second aspect of the present invention, in addition to the above,
By disposing a frusto-conical check valve that covers the oil passage while being pressed by the diaphragm and bent while facing the oil passage that opens to the tapered surface of the bottom case, the hydraulic oil chamber in the cylinder and the oil chamber of the accumulator While increasing the flow path area of the oil passage that communicates with the oil passage, the check valve closes the oil passage at zero-down while preventing the diaphragm from biting into the oil passage and being damaged, and the high-pressure gas in the gas chamber of the accumulator is reduced. It is possible to eliminate the fear that the oil is blown out together with the hydraulic oil in the oil chamber and the cylinder, or that all of the high-pressure gas is discharged to the hydraulic circuit for control and the original function of the suspension cylinder is no longer possible. .

Similarly, according to the third aspect of the present invention, since the slit is radially formed from the portion on the reduced diameter side with respect to the check valve, the oil that communicates the hydraulic oil chamber in the cylinder with the oil chamber of the accumulator is provided. While the flow path area of the passage is made larger, and at the time of zero down, the check valve closes the oil passage and prevents the diaphragm from biting into the oil passage and being damaged. It is possible to eliminate the possibility that the hydraulic fluid in the chamber and the cylinder is blown out together with the hydraulic oil, or that all of the high-pressure gas is discharged to the hydraulic circuit for control and the original function as the suspension cylinder is no longer possible. Become.

According to the fourth aspect of the present invention, the outer peripheral portion of the check valve is fixed together with the diaphragm between the outer shell and the bottom case. While preventing the check valve from deviating from the normal position due to vibration,
The reliability of the function as a check valve can be improved.

According to the fifth aspect of the present invention, the wall surface of the outer shell between the fixed portions at both ends of the diaphragm is bulged outward, so that the outer shell has the advantages described above. When assembling the cylinder into the cylinder, it is possible to facilitate the assembling while preventing damage to the sandwiched portions of both ends of the diaphragm, and to secure the volume of the gas chamber to a specified amount.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of a vehicle suspension cylinder according to the present invention, which is longitudinally cut along an axis.

FIG. 2 is an enlarged partial longitudinal front view showing another embodiment of the vehicle suspension cylinder according to the present invention.

FIG. 3 is a front view showing a check valve used in the above, which is longitudinally cut along an axis. 4

FIG. 4 is a longitudinal sectional front view showing a vehicle suspension cylinder according to another embodiment of the present invention in a partially enlarged manner as in the above.

FIG. 5 is a bottom view of the check valve used in the above as viewed from below.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Suspension cylinder for vehicles 2 Piston rod 3 Leveling oilway 4 Cylinder 5 Bearing 7 Piston 9 Bottom case 14 Extension damping valve 15 Compression damping valve 16, 17 Fixed portion at both ends of diaphragm 18 Tapered surface of bearing 19 Tapered surface of bottom case 20 Lower cap 21 Outer shell 22 Diaphragm 23 Oil chamber 24 Gas chamber 25, 26 Oil path 27 Gas supply port 28 Sealing plug 30 Packing case 33 Suspension spring 34, 34a Check valve 35 Slit

Claims (5)

[Claims] 1. A suspension cylinder for a vehicle in which a cylinder and an outer shell are partitioned into an oil chamber and a gas chamber by a diaphragm, and both ends of the diaphragm are fixed by being sandwiched between an outer shell, a bearing provided on a cylinder side, and a bottom case. The bearing and the bottom case portion extending from the fixed portion of the diaphragm to the outer wall surface of the cylinder are formed as a gentle tapered surface, and the oil passage leading to the inside of the cylinder is opened in the tapered surface portion. Characteristic suspension cylinder for vehicles. 2. A suspension cylinder for a vehicle according to claim 1, wherein a frusto-conical check valve for covering the oil passage while being deflected by being pressed by a diaphragm is disposed opposite to the oil passage opening to the tapered surface of the bottom case. . 3. The suspension cylinder for a vehicle according to claim 2, wherein a slit is radially formed from a portion on the reduced diameter side of the check valve. 4. The vehicle suspension cylinder according to claim 2, wherein the outer peripheral portion of the check valve is fixed together with the diaphragm between the outer shell and the bottom case. 5. The outer shell wall between the fixed portions at both ends of the diaphragm bulges outward.
2, 3 or 4 suspension cylinders for vehicles.