JPH0440572B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hydraulic shock absorber for vehicles, etc., which particularly exhibits an anti-roll function, and also has a general damping function as a shock absorber. The present invention relates to a hydraulic shock absorber for two-wheeled vehicles, four-wheeled vehicles, etc., which also has an anti-roll function.

[Conventional technology]

2. Description of the Related Art It is well known that a vehicle is equipped with a vehicle attitude control device in order to improve the running stability of the vehicle, and various vehicle attitude control devices have been proposed in the past. In order to prevent the roll phenomenon in which the outside of the vehicle sinks significantly when the vehicle makes a sharp turn, these conventional vehicle body attitude control devices generate a large reaction force on the vehicle height adjuster that is subject to the sinking effect. , has been proposed as an anti-roll function.

For example, a vehicle body attitude control device as shown in FIG. 5 has been proposed. The vehicle body attitude control device according to this proposal has a pair of left and right vehicle height adjusters 1, 1, and a cylinder 1a constituting each vehicle height adjuster 1 is defined by a piston portion 1b. It has an upper chamber A and a lower chamber B,
Moreover, one upper chamber A communicates with the other lower chamber B, and one lower chamber B communicates with the other upper chamber A, respectively, in a so-called sash-like manner. Each cylinder 1a has a gas chamber G at its inner upper end,
Each vehicle height adjuster 1 has its upper end connected to the vehicle body side, and its lower end connected to the axle side.

With this, for example, the left and right vehicle height adjusters 1,
1 contract in the same phase, each upper chamber A compresses the gas chamber G by the volume of entry of the piston rod 1c. At this time, the gas chamber G is compressed by the amount of the intrusion volume of the piston rod 1c, so the reaction force generated in each piston rod 1c is small, and it deteriorates the ride comfort during normal driving of the vehicle. Never. When the left and right vehicle height adjusters 1, 1 expand and contract in opposite phases, that is, when the vehicle makes a sharp turn, for example, the right vehicle height adjuster 1 in the figure contracts and the left vehicle height adjuster 1 contracts. When the vehicle height adjuster 1 is extended, the right upper chamber A is not only compressed by itself, but also receives pressure from the left lower chamber B, and at this time, the right gas chamber G is extremely compressed. It is possible to receive a large amount of pressure, that is, to generate an extremely large reaction force, thereby exhibiting an anti-roll function and providing driving stability of the vehicle.

[Problem that the invention seeks to solve]

However, in the case of the above conventional example, since the passage must be formed in a so-called sash shape, there is a drawback in that installation space is limited when installing it on a vehicle, and the vehicle body posture of this conventional example is The control device is originally installed on the vehicle for the sole purpose of exhibiting the anti-roll function, so a shock absorber to improve the ride comfort of the vehicle must be separately installed on the vehicle. This results in the inconvenience that space is increasingly restricted and the number of parts increases. Then, the upper chamber A and the lower chamber B in each vehicle height adjuster 1
and are formed independently of each other,
Oil leakage in piston portion 1b or cylinder 1a
If there is an oil leak to the outside, a change in the amount of oil in the upper chamber A and the lower chamber B or a change in the volume in the gas chamber G will result, and as a result,
There is a concern that the characteristics of the repulsive force may change.
Furthermore, when the temperature of the vehicle height adjuster increases,
When the oil in the vehicle height adjuster expands and compresses the gas chamber, causing even a slight roll phenomenon, that is, an opposite phase, a large reaction force is generated, and even when the phases are the same, a large reaction force is generated. becomes easier,
There are also inconveniences such as deteriorating the ride comfort of the vehicle and reducing the durability of the vehicle height adjuster.

Therefore, in view of the above-mentioned circumstances, the present invention is capable of being installed in a vehicle without much space constraints, is economical, and furthermore, does not cause changes in repulsive force characteristics. , can exhibit not only damping force function but also anti-roll function,
The purpose of this invention is to provide a new hydraulic shock absorber for vehicles that can improve the riding comfort and handling stability of vehicles.

[Means for solving problems]

In order to achieve this objective, the structure of the present invention is
The cylinder has an upper chamber and a lower chamber partitioned by a piston part, and a reservoir chamber outside the cylinder, and is arranged between the lower chamber and the reservoir chamber to provide a compression side damping force. In a hydraulic shock absorber having a base valve part that generates a pressure, the piston part is provided with an extension valve that communicates the upper chamber and the lower chamber only during the extension operation, and the base valve part connects the lower chamber and the reservoir chamber. A damping force generating valve and a throttle valve are provided in the middle of the connecting passageway, and the damping force generating valve is provided with a passage leading to the reservoir chamber side at the back of the damping force generating valve, and this passage is provided in the damping force generating valve. A check valve that communicates with the lower chamber through an orifice and is opened and closed by an external pressure signal is provided in the middle of the passage, and when the check valve is closed by the external pressure signal, the piston part is prevented from descending, and further damping force is applied. This is characterized in that the passage between the generation valve and the throttle valve is communicated with the upper chamber so that the front pressure of the throttle valve is guided to the upper chamber.

〔Example〕

The present invention will be explained below based on the illustrated embodiments.

As shown in FIG. 1, the hydraulic shock absorber according to the present invention has an upper chamber A and a lower chamber B partitioned by a piston part 20 in a cylinder 10, and a reservoir chamber C outside the cylinder 10. have. and,
A base valve section 30 is provided at the bottom of the cylinder 10 to open and close the lower chamber B and the reservoir chamber C. Note that the upper end of this device is connected to the vehicle body side of the vehicle, and the lower end is connected to the axle side of the vehicle.

A hollow pipe 9 and an outer shell 11 are disposed outside the cylinder 10, a passage a is formed between the cylinder 10 and the pipe 9, and a reservoir chamber is formed between the pipe 9 and the outer shell 11. This is considered to be C. A cap 8 is fixed inside the upper end of the outer shell 11, a sealing member 13 is disposed inside the cap 8, and a bearing member is installed inside the upper end of the cylinder 10 and the pipe 9. 14 are arranged.

A passage a is formed between the cylinder 10 and the pipe 9, and the passage a is formed in the through hole 7 bored in the upper end of the cylinder 10 and in the adjacent bearing member 14 opposite thereto. passage 7'
It communicates with the upper chamber A via. Furthermore, the through hole 7 bored in the cylinder 10 has a check valve 16 disposed on the bearing member 14 side so as to be openable and closable.
This allows oil to pass from the passage a into the upper chamber A, but blocks the passage of oil from the upper chamber A to the passage a.

The piston part 20 is attached to the lower end spigot part of the piston rod 21 which is slidably inserted into the cylinder 10.
It has a growth side valve 22 that generates a growth side damping force when rising within zero.

That is, a piston body 23 is disposed at the lower end spigot part of the piston rod 21, and the piston body 23 divides the inside of the cylinder 10 into an upper chamber A and a lower chamber B. The extension valve 22, which is comprised of a poppet-shaped valve body 26 and a spring 25, is provided on the lower side, that is, on the lower chamber B side. A passage 6 is bored in the piston rod 21 so that the upper chamber A and the lower chamber B in the cylinder 10 can communicate with each other.
The expansion side valve 22 is formed by disposing a valve body 26 facing the passage 6 so as to be openable and closable by a spring 25 in a housing 24 communicating with the passage 6. It is something that has been done.

Therefore, when the piston portion 20 moves up within the cylinder 10, the oil in the upper chamber A flows through the passage 6 of the piston rod 21 since the upper chamber A and the passage a are closed by the check valve 16. together with the valve body 2
6 overcoming the repulsive force of the spring 25 and pushing down, it flows into the housing 24 through the gap created, and flows into the lower chamber B through the through hole 24a formed in this housing 24. At this time, the flow resistance in the gap generates the desired rebound damping force. Note that when the piston portion 20 moves down inside the cylinder 10, the valve body 2
6 closes the passage 6 of the piston rod 21, so there is no flow of oil from the lower chamber B to the upper chamber A via the piston portion 20.

In this embodiment, the piston portion 20 is provided with the expansion side valve 22, but this valve may be provided at a different position and only the piston body 23 is provided, and the expansion side valve 22 may be omitted. You can also use it as Further, when the expansion side valve 22 is disposed in the piston portion 20, it goes without saying that the valve body 26 of this embodiment may be replaced with another valve.

The base valve section 30 includes the piston section 2
0 is configured to generate a desired compression side damping force during the compression stroke in which the cylinder 10 descends.

The base valve part 30 includes a cylinder 10 and a pipe 9.
A damping force generating valve consists of a valve housing 31 held at the lower end, a valve body 32 inserted and held in the valve housing 31, a poppet valve 33 inserted in the valve body 32, and a damping force generating valve formed on the back of the poppet valve 33. A check valve consisting of a ball valve 34 provided, a free piston 35 that opens and closes the ball valve 34, and a through hole 36 in the valve body 32.
It has a valve member 37 which is an upper throttle valve.

A bottom 11' is fixed to the lower end of the outer shell 11, and a valve housing 31 with a cutout 38 stands up on the bottom 11'.A central hole 39 and a vertical hole are formed in the upper part of the valve housing 31. 40, and also forms a lateral through hole 41 that opens to the passage a.

At the upper end of the valve housing 31, a leaf valve 42 with a hole 40 opened and closed and a hole formed in the center is provided so as to be openable and closable. A chamber 45 is defined between the valve housing 31 and the valve body 32 which are pushed downward, and this chamber 45 communicates with the passage a through the through hole 41 and opens and closes into the central hole 39 through the poppet valve 33. It is opened and closed to the lower chamber B through the through hole 40 and the leaf valve 42, and further communicates with the through hole 36 of the valve body 32 through the valve member 37. The through hole 36 communicates with the reservoir chamber C via a passage 46 defined below the valve body 32 and a notch 38 .

Therefore, the lower chamber B communicates with the reservoir chamber C via a passage consisting of a central hole 39, a chamber 45, a through hole 36, a passage 46, and a notch 38, and a damping force generating valve and a valve member 37 are disposed in the middle of this passage. In addition, the passage between the poppet valve 33 and the valve member 37 communicates with the passage a through the through hole 41, and this passage a connects to the upper chamber through the check valve 16. This means that you are familiar with A.

As shown in FIG. 3, the valve member 37 includes a non-return valve 47 that is movably provided at the upper end of the through hole 36 of the valve body 32, and a non-return valve 47 that is movable up and down.
It consists of a leaf valve 49 that opens and closes the hole 48 of No. 7, a leaf spring 50 that is interposed between a stopper 51 held on the outer periphery of the valve body 32, and the non-return valve 47.
oil opens the leaf valve 49 from the chamber 45 and the hole 4
8 to the reservoir chamber C, and at this time, the resistance of the leaf valve 49 cooperates with the poppet valve 33 to produce a damping force and build up pressure in the chamber 45. With this pressure, a part of the oil flows from the passage a to the upper chamber A. I try to make it easier to flow.

The valve body 32 is hollow and has a passage 52 formed therein, and is provided with a step 53 on its inner periphery, which is biased upwardly by a spring 54 above the step, and has a hole d in the center. A provided poppet valve 33 is slidably inserted into the poppet valve 33.
The valve head contacts the mouth end seat of the central hole 39 to open and close it.

A valve seat 55 is held below the stepped portion 53, and further below the valve seat 55, a check valve consisting of a ball valve 34 and a free piston 35 are loosely fitted so as to be movable up and down. Passage 56 between
One end of the passage 56 is opened and closed within the passage 52 via the ball valve 34, and the other end of the passage 56 communicates with the chamber 45 via a bypass 57 provided within the valve body 32.

The free piston 35 is used to open and close the check valve, and is normally biased downward by a spring 58 provided between the free piston 35 and the valve body 32.

A pressure chamber 59 is defined below the free piston 35, and this pressure chamber 59 is selectively communicated with a pneumatic or hydraulic pressure source or a low pressure side through a passage 60 and a port 61 provided in the bottom 11'. It is becoming more and more common.

Next, we will discuss the operation.

First, the case where it is used as a general shock absorber for generating damping force will be described.

For vehicles with pneumatic pressure, the external pressure signal is set to port 61 at atmospheric pressure or 1
Connect to the low pressure side of ~2Kgf/cm ² . At this time, the free piston 35 is pushed downward by the spring 58 because the pressure in the pressure chamber 59 is low, and the ball valve 34 thereby opens the passage 56. When the piston part 20 is extended in this state, the piston part 20 rises, the upper chamber A is compressed, and the lower chamber B is expanded. Upper chamber A
Since the flow of the oil toward the passage a side is blocked by the check valve 16, it acts on the valve body 26, which is the expansion side valve 22, through the passage 6, and the valve body 26 is pushed open against the spring 25. It flows into the lower chamber B through the through hole 24a, and at this time, the action of the valve body 26 generates a rebound damping force.

On the other hand, the oil corresponding to the protruding volume of the piston rod 21 is
Push up the non-return valve 47 from the reservoir chamber C through the notch 38 - passage 46 - through hole 36,
Further, the leaf valve 42 is pushed open through the chamber 45-through hole 40 and introduced into the lower chamber B, thereby preventing negative pressure.

Next, during compression, the piston part 20 descends and the upper chamber A is enlarged, but the oil in the lower chamber B is not introduced into the upper chamber A because it is blocked by the poppet valve 26, which is the extension valve 22. , a check valve 1 is installed in the upper chamber A.
6 is opened and oil in the passage a is introduced through the through hole 7 to the through hole 7', thereby preventing negative pressure.

On the other hand, the compressed oil in the lower chamber B acts on the poppet valve 33 through the central hole 39. The oil flowing out from the central orifice d of the poppet valve 33 is in a free flow state toward the chamber 45 via the passage 52 - passage 56 - bypass 57, and as a result, the oil flows freely into the chamber 45 side through the passage 52 - passage 56 - bypass 57.
The pressure in chamber 45 is the same as the pressure in chamber 45. For this reason, the poppet valve 33 loses the balance between the hydraulic pressure acting from the upper chamber B and the hydraulic pressure acting from the passage 52, and the hydraulic resistance pressure generated by the central hole d of the poppet valve 33 and the pressure received by the poppet valve 33 are lost. The product of the areas overcomes the spring 54, which causes the poppet valve 33 to open and the oil in the lower chamber B to flow out into the chamber 45. Further, the oil flowing into the chamber 45 opens the leaf valve 49 through the hole 48 in the valve member 37, and is further returned to the reservoir chamber C through the through hole 36, passage 46, and notch 38.

Thus, the action of the poppet 33 and the action of the leaf valve 49 generate a compression damping force. Moreover,
What should be noted here is that the hydraulic resistance generated by the valve member 37 acts on the passage a, and the oil in the passage a more efficiently pushes open the check valve 16 to open the upper chamber A.
This means that it is becoming easier to flow.

Next, we will explain how to use it to provide an anti-roll function.

In this case, the port 61 is connected to a pressure source, and a pressure of, for example, 4 to 8 Kgf/cm ² is sent to the pressure chamber 59 as an external pressure signal.

For this reason, the pressure in the pressure chamber 59 frees the piston 3.
5 rises against the tension of the spring 58 and the pressure from the passage 52, whereby the ball valve 34 blocks the mouth end of the passage 56, and the oil in the passage 52 does not flow to the chamber 45 side. Therefore, the pressures in the lower chamber B and the passage 52 become the same, the poppet valve 33 becomes in a pressure balanced state, the mouth end of the central hole 39 is closed by the spring 54, and the lower chamber B and the chamber 45 are in a closed state. .

In this state, when the vehicle body is tilted and compression is attempted, the lower chamber B is blocked by the poppet valves 26 and 33 and the leaf valve 42, and oil does not flow into the upper chamber A or the reservoir chamber C. Since the piston part 20 is locked to the position, the piston part 20 does not descend. The fact that the piston portion 20 does not fall means that the hydraulic shock absorber acts as a rod and is stretched, thereby preventing the vehicle body from tilting and providing anti-roll.

The extension operation is the same as the extension operation during normal driving described above.

By the way, the specified pressure to port 61 (4 to 8 kg
f/cm ² ) will set the upward acting force of the free piston 35.

That is, it corresponds to the acting force of the pressure of the passage 52 acting on the spring 58 and the ball valve 34, and the compression locking force and the compression damping force are determined by the pressure supplied to the port 61.

Therefore, by changing the supply pressure to the port 61 depending on the usage status of the vehicle, the locking force and the compression damping force can be changed.

For example, if the supply pressure to port 61 is set to be high when the machine is stopped, and the supply pressure is set to increase in proportion to the steering angle, the lock will be large when the machine is stopped, and it will be useful for loading and unloading cargo and on slopes. It is possible to prevent the vehicle from tilting, etc., and when the vehicle is cornering,
An anti-roll force is applied in response to steering of the steering wheel, and roll can be effectively prevented.

Furthermore, in the case of a vehicle with an air spring type suspension spring, if the internal pressure of the air spring is used as the supply pressure to port 61, it is possible to generate a locking force (damping force) according to the operation of the suspension spring, and the automatic It is possible to effectively prevent rolls.

In the present invention, the compression side has a locking action, and the expansion side is free. This is because, as mentioned above, when considering roll prevention during driving, it is important for steering stability to have both left and right wheels in constant contact with the road surface.

As described above, according to the present invention, a single hydraulic shock absorber not only functions as a shock absorber but also as a vehicle body attitude control device, so it can be installed in a vehicle without being subject to space constraints. , the number of parts is small, making it possible to reduce costs and simplifying the installation work. Furthermore, since it can be independently disposed on each of the four wheels, there is an advantage that there is no need to worry about space constraints when equipping the vehicle.
In addition, since the reservoir chamber volume can be set large, changes in repulsion force characteristics due to temperature changes or changes in oil amount will not occur, which will worsen the ride comfort of the vehicle or impede the running stability of the vehicle. There is no fear that this will happen. A further advantage is that it is possible to prevent the vehicle from tilting to one side only due to a change in the load when the vehicle is stopped.

Further, by providing a throttle valve, its hydraulic resistance improves the efficiency of sucking oil into the upper chamber during compression, thereby preventing the generation of negative pressure.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional front view of a hydraulic shock absorber according to an embodiment of the present invention, FIG. 2 is a partially enlarged sectional view of FIG. 1,
FIG. 3 is an enlarged sectional view of the throttle valve, FIG. 4 is a cross-sectional view taken along the line -- in FIG. 1, and FIG. 5 is a schematic diagram of a conventional vehicle body attitude control system. 10...Cylinder, 20...Piston part, 30
... Base valve part, 33 ... Poppet valve, 34
...Check valve, 37... Throttle valve, 52...
Passageway, A...upper chamber, B...lower chamber, C...reservoir chamber.

Claims (1)

[Claims] 1. A cylinder having an upper chamber and a lower chamber partitioned by a piston part, and a reservoir chamber outside the cylinder, and between the lower chamber and the reservoir chamber. In a hydraulic shock absorber having a base valve section disposed to generate a compression damping force, the piston section is provided with an extension valve that communicates the upper chamber and the lower chamber only during extension operation, and the base valve section is A damping force generating valve and a throttle valve are provided in the middle of the passage connecting the lower chamber and the reservoir chamber, and are provided so as to be freely openable and closable.A passage leading to the reservoir chamber is provided at the back of the damping force generating valve, and this passage is connected to the damping force generating valve. It communicates with the lower chamber through an orifice provided in the force generating valve, and furthermore, a check valve that is opened and closed by an external pressure signal is provided in the middle of the passage, and when the check valve is closed by the external pressure signal, the piston portion is lowered. This hydraulic shock absorber is configured to prevent the damping force generating valve and the throttle valve from being blocked, and to communicate the middle of the passage between the damping force generating valve and the throttle valve with an upper chamber to guide the front pressure of the throttle valve to the upper chamber. 2. The hydraulic shock absorber according to claim 1, wherein the damping force generating valve is a poppet valve.