JPH0942362A - Car height regulating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress increasing of reaction at the time of pumping so as to improve riding comfortableness by communicating a rod side oil chamber and a reservoir with each other through an oil sump chamber formed between a main seat and an oil seal, and interposing a check valve which is opened only at the time of compression in a passage for connecting a pump mechanism and the rod side oil chamber to each other. SOLUTION: When a spring upper load is increased, it is balanced with a spring with a condition in which a car height falls down, and the car height drops down, a bearing 28 falls down through a piston rod 13, and a control orifice O is closed by a bearing 28. When running is continued in a condition of the car height, a piston 22 is slid vertically by recessed/projection conditions of a road surface, a pump mechanism P is pumping-operated, a discharging passage 44 and a discharging check valve 17 are opened by pressure oil compressed in a pump chamber A in a compression stroke, and pressure oil is discharged toward a rod side oil chamber B. At this time an opposite rod side oil chamber D is compressed, pressure oil is supplied into the oil chamber B, and thereby, oil in the oil chamber D is discharged into the oil chamber G of an accumulator Q side through the passages 46, 47.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle height adjusting device which is interposed between a vehicle body and an axle of a vehicle to damp vibrations from a road surface and to control the vehicle height to a constant height regardless of sprung load.

[0002]

2. Description of the Related Art As a vehicle height adjusting device of this type, for example, one disclosed in Japanese Patent Laid-Open No. 7-1444524 has been developed.

This vehicle height adjusting device supplies pressure oil to a shock absorber, an accumulator incorporated in the shock absorber, an anti-rod side oil chamber of the shock absorber and an oil chamber on the accumulator side of the shock absorber. It has a pump mechanism for supplying and a control orifice provided in the shock absorber for controlling the height of the shock absorber. In this case, the shock absorber includes a vehicle body side cylinder, an outer shell, a reservoir provided between the cylinder and the outer shell, an axle side piston rod movably inserted into the cylinder via a piston, and a piston. It is composed of a partitioned lower rod-side oil chamber and an upper non-rod-side oil chamber.

Similarly, the accumulator is disposed below the cylinder and the outer shell. The accumulator is composed of a gas chamber and an oil chamber defined by a diaphragm, and the upper end of the diaphragm is a housing defining a reservoir and the outer. Both ends of the diaphragm form a seal with the shell and are fixed through the seal. Similarly, the lower end of the diaphragm is connected between the lower case that seals the cylinder and the outer shell and the outer shell, and the gas chamber The gas is to be sealed in through the gas sealing hole formed in the side portion of the outer shell.

Further, in the pump mechanism, a pump chamber provided in the piston rod, an inner rod inserted into the pump chamber from above, a pump chamber and a reservoir are connected, and an inner rod provided with a discharge check valve in the middle is connected. Intake passage of
The pump chamber is connected to the upper anti-rod side oil chamber and the accumulator side oil chamber, and a discharge passage inside the piston rod is provided with a discharge check valve in the middle. Further, the piston rod penetrates the lower case via the upper and lower two-stage seals.

The piston rod is provided with a control orifice for connecting the suction passage and the oil chamber on the side opposite to the rod. The control orifice, the pump mechanism and the accumulator control the height of the shock absorber to keep the vehicle height constant. ing.

[0007]

However, the conventional vehicle height adjusting device described above has the following problems.

First, since the piston rod is axially sealed by two upper and lower seals provided in the lower case to prevent oil from leaking to the outside, it is inevitably necessary to increase the tightening margin of each seal. As a result, the rod sliding frictional resistance of the piston rod that comes into sliding contact with the upper and lower seals is increased, and the expansion / contraction operation is not smooth.

Secondly, since the pressure oil discharged from the pump mechanism is discharged to the opposite rod side chamber that is compressed during compression, the reaction force during pumping increases and the damping force characteristic during compression stroke increases. The riding comfort of the vehicle becomes poor.

Thirdly, the gas chamber of the accumulator is filled with gas through a gas filling hole provided on the side portion of the outer shell, so that the workability of filling the gas is poor and the gas filling is large. It requires a jig and is less economical. or,
Since the sealed gas is prevented from leaking only by the seal portion at the end of the diaphragm, there is a possibility of gas leaking and the reliability is poor.

Therefore, an object of the present invention is to reduce the sliding frictional resistance of the piston rod, the reaction force does not increase during pumping, the riding comfort of the vehicle is not deteriorated, and it is easy to fill the accumulator with gas and there is a risk of gas leakage. It is to provide a vehicle height adjusting device for preventing the above.

[0012]

In order to achieve the above object, the structure of the present invention has a shock absorber interposed between a vehicle body and an axle, an accumulator communicating with the shock absorber, a shock absorber and an accumulator. A pump mechanism for supplying pressure oil to the, and a control orifice provided in the shock absorber for controlling the height of the shock absorber, the shock absorber is a cylinder, and an outer shell arranged outside the cylinder,
A reservoir partitioned between the cylinder and the outer shell, a hollow piston rod movably inserted into the cylinder via a piston, a rod-side oil chamber and an anti-rod-side oil chamber partitioned by the piston in the cylinder. The pump mechanism is arranged in the piston rod and supplies the pressure oil of the reservoir to the oil chamber on the shock absorber side and the oil chamber on the accumulator side at the time of expansion and contraction operation, and the control orifice is at a predetermined position. In the vehicle height adjusting device that communicates the oil chamber on the side with the reservoir to set the shock absorber to a predetermined height, the piston rod has a main seal provided at the end of the cylinder and an oil seal provided at the end of the outer shell. So that the rod-side oil chamber and the reservoir are located between the inner gap of the main seal and the main seal and oil seal. Communicated via the an oil reservoir chamber,
Further, the present invention is characterized in that a check valve that is opened only during compression is provided in a passage that connects the pump mechanism and the rod-side oil chamber.

In this case, a lower case for sealing the cylinder is provided at the lower end of the cylinder and the lower end of the outer shell, an accumulator consisting of a gas chamber and an oil chamber is arranged between the cylinder and the outer shell, and the oil chamber of the accumulator and the shock absorber are arranged. It is preferable that the non-rod side oil chamber is communicated with a lower case through a passage provided in the lower case, and that gas is introduced into the gas chamber of the accumulator through the lower gap of the lower case.

Alternatively, a lower case for sealing the cylinder is provided at the lower end of the cylinder and the lower end of the outer shell, an accumulator consisting of a gas chamber and an oil chamber is provided outside the outer shell, and the passage provided in the lower case and the outer shell are penetrated. The oil chamber of the accumulator and the anti-rod side oil chamber of the shock absorber may be communicated with each other via the pipe.

Further, the pump mechanism has a pump chamber provided in a hollow piston rod, an inner rod whose base end is fixed to the lower case and is inserted from the lower end of the piston rod into the pump chamber, and a lower case and an inner rod. A suction passage communicating the reservoir and the pump chamber, a discharge passage formed in the piston rod to communicate the pump chamber and the rod side oil chamber, and a suction check valve provided in the middle of the suction passage so as to be openable and closable. A discharge check valve provided in the middle of the discharge passage is preferable.

Further, it is preferable that a control orifice that connects the suction passage and the oil chamber on the side opposite to the rod is formed in the inner rod, and a bearing that opens and closes the control orifice is provided at the lower end of the piston rod.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention. The vehicle height adjusting device shown in FIG. , A shock absorber S interposed between the vehicle body and the axle, an accumulator Q communicating with the shock absorber S, a pump mechanism P for supplying pressure oil to the shock absorber S and the accumulator Q, and a shock absorber S provided in the shock absorber S. Control orifice O for controlling the height of the shock absorber S.

The shock absorber S is a cylinder 9
And an outer shell 8 arranged outside the cylinder 9,
A reservoir C partitioned between the cylinder 9 and the outer shell 8, a hollow piston rod 13 movably inserted into the cylinder 9 via a piston 22, and a rod-side oil partitioned by the piston 22 in the cylinder 9. The chamber B and the non-rod side oil chamber D are configured.

The pump mechanism P includes the piston rod 13
The pressure oil of the reservoir C is provided inside the oil chamber B for supplying the pressure oil of the reservoir C to the rod-side oil chamber B on the shock absorber side and the oil chamber G on the accumulator side. Is communicated with the reservoir C and the shock absorber S is set to a predetermined height.

More specifically, the piston rod 13 is movably inserted into the cylinder 9 via the piston 22, and the upper rod-side oil chamber B and the lower anti-rod-side oil chamber are inserted into the cylinder 9 by the piston 22. D and the two oil chambers B1 and D communicate with each other via a damping force generation mechanism provided in the piston 22. Below the piston rod 13, a rebound cushion 14, a rebound stopper 15, a can 16, a discharge check valve 17, a disk 18, a plate 19, a can 20, a pressure side leaf valve 21, a piston 22, and an extension. Side leaf valve 23
The canzer 24, the main valve 25, the main valve spring 26, and the piston nut 27 are sequentially inserted in series from the upper side to the lower side, and these piston assemblies are held by the piston nut 27.

The damping force generating mechanism includes ports a and b provided on the piston 22, a pressure side leaf valve that is openably and closably provided at the outlet end of the port b, an expansion side leaf valve 23 provided at the outlet end of the port a, and The main valve 25 and.

A bearing 3 is provided on the upper end of the cylinder 9, a packing case 1 is provided on the upper end of the outer shell 8 as well, and a main seal 4 slidingly contacting the piston rod 13 is provided on the inner periphery of the bearing 3. An oil seal 2 that is in sliding contact with the piston rod 13 is provided on the inner circumference of the packing case 1.

The bearing 3 is fitted inside the packing case 1, and an oil storage chamber H is defined between the oil seal 2 and the main seal 4, and the oil storage chamber H leaks from the cylinder 9. Port I provided on bearing 3 after oil is stored
It returns to the reservoir C via.

The oil in the rod side oil chamber B of the cylinder 9 is collected in the reservoir C even if it leaks from the main seal 4,
It is not necessary to increase the tightening margin of the main seal, so that the sliding resistance of the piston rod 13 is small and the expansion and contraction operation can be smoothly performed.

O-rings 5 and 7 are provided on the outer circumferences of the bearing 3 and the packing case 1 for sealing.

A body 41 and a lower case 32 are respectively provided at the lower end of the cylinder 9 and the lower end of the outer shell 8. These two upper and lower bodies 41 and 32 are
The upper body 41 is fitted to the lower end of the cylinder 9 via the seal 34, and the lower case 32 is supported on the lower surface of the outer shell 8.

A pump chamber A is defined in the piston rod 13, and a hollow inner rod 29 is provided in the pump chamber A.
The base end of the inner rod 29 is connected to the upper body 41 via a seal 33 and a stopper 42, and the suction passage 43 provided in the inner rod 29 is pumped via the absorption check valve 12. It is opened and closed in room A.

The suction check valve 12 is the inner rod 2
A spring 11 supported by a perforated or octopus-shaped cover 10 coupled to the upper end of 9 is normally biased in the closing direction.

A discharge passage 44 is formed in the piston rod 13 and the disk 18 to connect the pump chamber A and the rod-side oil chamber B. A discharge check valve 17 that opens only during compression is opened and closed at the outlet end of the discharge passage 44. It is provided freely.

A control orifice O is formed below the inner rod 29, and this control orifice O communicates the non-rod side oil chamber D with the suction passage 43. Further, a bearing 28 as a valve body is provided inside the piston nut 27, and the bearing 28 slides on the outer periphery of the inner rod 29 at the time of expansion and contraction and controls the opening and closing of the control orifice O.

The lower end of the inner tube 30 is fitted to the outer periphery of the upper body 41 through a seal 35, and the upper end of the inner tube 30 is provided with a diaphragm retainer 40 which is in close contact with the inner periphery of the outer shell 8. The inner tube 30 and the diaphragm retainer 40 define a reservoir C above the cylinder 9 and the outer shell 8. A chamber E and a lateral passage 45 are formed in the upper body 41, and these chamber E and the passage 45 are formed by the inner rod 2
The suction passage 43 in 9 is communicated with the reservoir C.

Inner tube 30 and outer shell 8
An accumulator Q is provided between the accumulator Q and the oil chamber G and the gas chamber F divided by the diaphragm 31.
The lower end of the diaphragm 31 is connected to the outer periphery of the lower case 32 below, and the upper end thereof is held by the diaphragm retainer 40 and the outer shell 8.

The body 41 has passages 4 in the vertical and horizontal directions.
6 and 47 are formed, and these passages 46 and 47 connect the anti-rod side oil chamber D to the oil chamber G of the accumulator Q.

Lower end lower cap 37 of outer shell 8
Is formed with a gas filling hole. The gas filling hole is communicated with the gas chamber F of the accumulator Q through the lower gap of the lower case 32, and after the gas is filled from the outside through the gas filling hole, the gas filling hole is formed. The plug 38 is inserted into the hole, and then the eye 39 is joined by welding to seal the gas chamber F.

Next, the operation will be described.

At the standard vehicle height of the vehicle in a state where the sprung load and the spring are in balance, the bearing 28, which is the valve body, is set to the position where the control orifice O is opened.

In this state, the number of passengers in the vehicle increases,
If the sprung load increases due to luggage or the like, the increased vehicle weight reduces the vehicle height in balance with the spring while the vehicle height sinks. At this time, piston rod 1
The bearing 28 descends via 3, and the bearing 28 closes the control orifice O. When the vehicle height continues to travel in this state, the piston rod 13 and the piston 22 slide up and down due to the unevenness of the road surface, and the pump mechanism P performs a pumping operation. That is, when the piston rod 13 and the piston 22 move upward by the extension operation, the volume of the pump chamber A increases, and the expanded volume of oil is sucked from the reservoir C through the passage 45 and the suction passage 43. 12 is opened and sucked. At this time, the oil in the rod side oil chamber B flows out to the non-rod side oil chamber D via the port a and the extension side leaf valve 23,
The expansion side leaf valve 23 generates a damping force.

Next, in the compression stroke, the pump chamber A is compressed and the rod-side oil chamber B is expanded.
The pressure oil pressurized therein is discharged into the rod-side oil chamber B by opening the discharge check valve 17 via the discharge passage 44. At this time, the suction check valve 12 is pressurized and closed. On the other hand, the anti-rod side oil chamber D is compressed, but since the oil is discharged from the pump chamber A to the rod side oil chamber B, the oil in the anti-rod side oil chamber D is stored in the body 41. Passages 46, 47
Through the oil chamber G on the accumulator Q side. This oil chamber G maintains a pressure balance with the gas chamber F,
Since the pressure oil is introduced into the oil chamber G, the gas chamber F is compressed, and the pressures of the oil chamber G, the non-rod side oil chamber D, and the rod side oil chamber B are entirely increased. When such a pumping operation is repeated during traveling, the pressure further rises, the rod reaction force increases, and the piston rod 13 gradually rises to raise the vehicle height. When the vehicle height rises to the standard vehicle height, the bearing 28 opens the control orifice O. Therefore, the oil in the anti-rod side oil chamber D flows out to the reservoir C via the control orifice O, the suction passage 43 in the inner rod 29, the chamber E in the body 41, and the passage 45, and the oil in the anti-rod side oil chamber D is formed. The pressures in the rod side oil chamber B and the oil chamber G in the accumulator Q are slightly lowered and the rod reaction force is lowered, whereby the piston rod 13 is lowered slightly and the vehicle height is lowered a little. When the bearing 28 descends to the position where it closes the control orifice O, the vehicle height reduction stops and the position is maintained. In short, even if the sprung load increases, the rod reaction force can be increased by the pumping operation during traveling to set the vehicle height to the standard position.

On the contrary to the above, when the occupant is reduced or the luggage is unloaded, the piston rod 1 is caused by the rod reaction force.
3 rises and the vehicle height rises, but at this time, the bearing 28
Since the control orifice O is opened, the oil in the oil chamber D on the side opposite to the rod flows out to the reservoir C as in the case described above, the pressure is slightly reduced, and the rod reaction force is also reduced, so the piston rod 13 is lowered and the vehicle height is the standard vehicle height. Set to position. Therefore, the vehicle height is set to the standard position during traveling regardless of the increase or decrease of the sprung load.

FIG. 2 shows another embodiment of the present invention,
In the vehicle height adjusting device of FIG. 1, the accumulator Q is mounted inside the shock absorber S, whereas the accumulator Q is arranged outside the shock absorber S. The shock absorber S is a reservoir C including a gas chamber and an oil chamber between the cylinder 9 and the outer shell 8.
Are provided to reduce the radial dimension.

An accumulator Q is attached to the outside of the shock absorber S via a bracket 50. The accumulator Q has a casing 51, a bottom 52 fitted to the casing 51, and a gas defined by a diaphragm 31 between the casing 51 and the bottom 52. It is composed of a chamber F and an oil chamber G. The gas chamber F is filled with gas from a port provided in the casing 51, and then sealed with a plug 55. A passage 53 that opens to the oil chamber G is formed in the bottom 52, and a pipe 54 is connected to the passage 53 so that the oil chamber G
Is connected to a passage 47 on the lower case 32 side via a pipe 54. The operation is the same as that of the embodiment of FIG. 1 except that the accumulator Q is provided outside. The same structures are denoted by the same reference numerals and detailed description thereof will be omitted.

[0042]

According to the present invention, the following effects can be obtained.

According to the inventions of the respective claims, the vehicle height can always be set to the standard vehicle height regardless of the increase or decrease of the sprung load, as in the known vehicle height adjusting device.

Since the oil leaked from the rod side oil chamber is collected from the oil reservoir to the reservoir side, it is not necessary to increase the tightening margin of the main seal, which can reduce the sliding friction resistance of the piston rod. The expansion / contraction operation can be performed smoothly.

Furthermore, since the discharge check valve is provided in the passage connecting the pump mechanism and the upper oil chamber on the rod side,
The oil discharged from the pump mechanism during the compression operation is discharged to the expanding rod-side oil chamber, and the pumping can be performed without increasing the pressure during pumping and without affecting the characteristics of the damping force during the pressure stroke.

According to the second aspect of the present invention, the gas is enclosed in the gas chamber of the accumulator through the lower gap of the lower case. Therefore, it is only necessary to close the gas inlet hole with a plug or the like after welding, and welding is performed. Since it does not require a special jig, it is highly economical, and there is no risk of gas leakage, improving reliability.

According to the third aspect of the invention, since the accumulator is provided outside the shock absorber, the radial dimension of the shock absorber can be made smaller than that in the case where the accumulator is incorporated in the shock absorber.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional front view of a vehicle height adjusting device according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional front view of a vehicle height adjusting device according to another embodiment of the present invention.

[Explanation of symbols] 2 Oil seal 4 Main seal 8 Outer shell 9 Cylinder 13 Piston rod 17 Check valve 22 Piston 44 Passage B Rod side oil chamber C Reservoir D Anti-rod side oil chamber H Oil reservoir O Control orifice P Pump mechanism Q Accumulator S Shock absorber

Claims (5)

[Claims] 1. A shock absorber interposed between a vehicle body and an axle, an accumulator communicating with the shock absorber, a pump mechanism for supplying pressure oil to the shock absorber and the accumulator, and a shock absorber provided in the shock absorber. The shock absorber comprises a cylinder, an outer shell arranged outside the cylinder, a reservoir partitioned between the cylinder and the outer shell, and a piston inside the cylinder via a piston. It consists of a hollow piston rod inserted movably, a rod-side oil chamber and an anti-rod-side oil chamber defined by a piston in the cylinder, and the pump mechanism is arranged in the piston rod and is used during expansion and contraction. Supply the pressure oil from the reservoir to the oil chamber on the shock absorber side and the oil chamber on the accumulator side. However, in the vehicle height adjusting device that sets the shock absorber to a predetermined height by communicating the oil chamber on the side of the accumulator with the reservoir at the predetermined position, the control orifice has the piston rod at the end of the cylinder and the outer seal. The oil seal provided at the end of the shell is movably penetrated, and the rod-side oil chamber and the reservoir communicate with each other through the inner gap of the main seal and the oil reservoir defined between the main seal and the oil seal. Further, the vehicle height adjusting device is characterized in that a check valve that is opened only during compression is provided in a passage that connects the pump mechanism and the rod-side oil chamber. 2. A lower case for sealing the cylinder is provided at a lower end of the cylinder and a lower end of the outer shell, an accumulator including a gas chamber and an oil chamber is provided between the cylinder and the outer shell, and an oil chamber of the accumulator and a shock absorber are provided. The vehicle height adjusting device according to claim 1, wherein the anti-rod side oil chamber is communicated with the lower case through a passage provided in the lower case, and the gas is introduced into the gas chamber of the accumulator through a lower gap of the lower case. 3. A lower case for sealing the cylinder is provided at a lower end of the cylinder and a lower end of the outer shell, and an accumulator including a gas chamber and an oil chamber is provided outside the outer shell,
2. The vehicle height adjusting device according to claim 1, wherein the oil chamber of the accumulator and the oil chamber on the non-rod side of the shock absorber communicate with each other through a passage provided in the lower case and a pipe penetrating the outer shell. 4. A pump chamber in which a pump mechanism is provided in a hollow piston rod, an inner rod whose base end is fixed to a lower case and is inserted from the lower end of the piston rod into the pump chamber, and a lower case and an inner rod. A suction passage communicating the reservoir and the pump chamber, a discharge passage formed in the piston rod to communicate the pump chamber and the rod side oil chamber, and a suction check valve provided in the middle of the suction passage so as to be openable and closable. The vehicle height adjusting device according to claim 3, comprising a discharge check valve provided in the middle of the discharge passage. 5. The vehicle height adjustment according to claim 4, wherein the inner rod is formed with a control orifice for communicating the suction passage with the oil chamber on the side opposite to the rod, and a bearing for opening and closing the control orifice is provided at a lower end of the piston rod. apparatus.