JPH0424200Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention provides a damping force that is provided between the car body and the chassis of a railway vehicle, for example, and is suitably used to buffer vibrations of the car body in the left-right direction. Concerning improvements to adjustable hydraulic shock absorbers.

[Prior art]

Generally, a railway vehicle is provided with a suspension system having an air spring and a suspension spring between the car body and the undercarriage. A left-right shock absorber is installed between the two.

This type of lateral movement shock absorber has conventionally consisted of an outer cylinder, an inner cylinder disposed within the outer cylinder, and an inner cylinder that is slidably inserted into the inner cylinder and has two oil chambers. a piston defining a piston; a piston rod having one end attached to the piston and the other end protruding outward from the inner cylinder and the outer cylinder; an oil passage communicating the two oil chambers through the outer cylinder; It consists of a damping force adjustment valve mechanism installed in the middle of the oil path, which adjusts the damping force generated when the piston rod extends and contracts.
A damping force adjustable hydraulic shock absorber is used which is adjusted by the damping force adjusting valve mechanism.

In the conventional damping force adjustable hydraulic shock absorber, the damping force adjusting valve mechanism includes a valve member, a spring that biases the valve member in the valve closing direction, and an adjustment screw that adjusts the biasing force of the spring. The damping force is adjusted by rotating the adjusting screw from the outside.

[Problem that the invention attempts to solve]

By the way, in the damping force adjustable hydraulic shock absorber according to the above-mentioned conventional technology, the damping force cannot be adjusted according to the vibration condition of the vehicle to which the shock absorber is installed, that is, the road surface condition and the traveling speed, and it is difficult to obtain the optimum ride comfort. The problem is that it cannot be guaranteed.

The present invention was developed in view of the drawbacks of the prior art described above, and the present invention is a damping force adjustable hydraulic system that can adjust the damping force according to the vibration state of the vehicle and always ensure optimal riding comfort. The purpose is to provide a buffer.

[Means for solving problems]

In order to solve the above-mentioned problems, the configuration adopted by the present invention includes an outer cylinder, an inner cylinder disposed inside the outer cylinder, and an inner cylinder slidably inserted into the inner cylinder. a piston defining two oil chambers therein; a piston rod having one end attached to the piston and the other end protruding outward from the inner cylinder and the outer cylinder;
In a damping force adjustable hydraulic shock absorber comprising an oil passage that communicates two oil chambers through an outer cylinder, and a damping force adjustment valve mechanism provided in the middle of the oil passage, the damping force adjustment valve mechanism includes a valve member provided in the middle of the oil passage so as to be displaceable in the axial direction, and a valve member provided on the tip side of the valve member that receives pressure in the oil passage to move the valve member to one side in the axial direction. a pressure receiving part to be displaced; a throttle part for generating a damping force that is provided on the valve member at a distance from the pressure receiving part and changes the degree of opening with respect to the oil passage in accordance with axial displacement of the valve member; and the valve member. a first movable partition wall that is provided on the proximal end side of the valve member and biases the valve member in the other axial direction by applying gas pressure;
a second movable bulkhead formed to have a larger diameter than the first movable bulkhead, and provided facing the first movable bulkhead so as to be able to touch and separate from the proximal end surface of the valve member; A pressure chamber defined between movable partition walls and to which gas pressure is supplied from the outside, and a second movable partition wall that is constantly energized toward the pressure chamber, and the supply of gas pressure to the pressure chamber is stopped. At times, the valve member includes a spring that urges the valve member to the other side in the axial direction via the second movable partition wall.

[Effect]

With the above configuration, if gas pressure that is increased or decreased depending on the vibration state of the vehicle is supplied to the pressure chamber, the second movable bulkhead is displaced against the spring by the gas pressure in the pressure chamber, and the valve As the first movable partition wall moves away from the proximal end surface of the member, the first movable partition urges the valve member toward the other side in the axial direction with a force corresponding to the gas pressure, and the hydraulic pressure in the oil passage is received by the pressure receiving part. As a result, displacement of the valve member on one side in the axial direction can be suppressed. As a result, the valve member is displaced in the axial direction according to the gas pressure, and the opening degree of the throttle section is controlled according to this displacement, so that the damping force generated by the oil flowing through the throttle section is reduced to the vibration of the vehicle. It can be adjusted depending on the situation.

Further, when the supply of gas pressure to the pressure chamber is stopped and the pressure chamber becomes atmospheric pressure, the second movable partition wall is biased by the spring and comes into contact with the valve member, thereby causing the valve member to open. Since the member can be biased toward the other side in the axial direction, the valve member can control the opening of the throttle section by displacing in the axial direction according to the spring load, and the damping force at this time can be adjusted based on the spring load. can.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 5, taking as an example the case where the present invention is used as a lateral vibration damper for damping lateral vibrations of a railway vehicle.

In the figure, 1 indicates the body of the vehicle, 2 indicates the chassis, and 3 indicates the wheels. Suspension springs 4, 4 are interposed between the wheels 3 and the chassis 2, and between the chassis 2 and the vehicle body 1, Air springs 5,5 are provided. A bracket 6 is provided on the vehicle body 1 to project downward, and a bracket 7 is provided on the chassis 2 to project upward.

Reference numeral 8 denotes a damping force adjustable hydraulic shock absorber, and the shock absorber 8 has a mounting portion 9 provided at its cylinder side end that is pivotally connected to the bracket 7 with a pin, and a mounting portion 10 provided at its rod side end. is pin-coupled to the bracket 6 so as to be swingable, and is adapted to buffer vibrations of the vehicle body 1 in the left-right direction.

Reference numeral 11 denotes a sensor provided inside the vehicle body 1. The sensor 11 detects displacement, acceleration, speed, etc. due to vibration of the vehicle body 1 in the left and right direction, and sends an electric signal S corresponding to the displacement, acceleration, speed, etc. as described later. It is designed to be output to the controller 12. 12
is a controller installed in the vehicle body 1, and the controller 12 controls the air pressure P as a gas pressure adjusted to a desired pressure state by opening and closing a servo valve (not shown) based on the electric signal S.
The air pressure is supplied to the pressure chamber D through an air pressure introduction hole 31A of the hydraulic shock absorber 8, which will be described later.

Next, the hydraulic shock absorber 8 will be explained with reference to FIG. That is, in the same figure, 13 is the outer cylinder 13A.
and an inner cylinder 13B arranged in the outer cylinder 13A, and one end side of the cylinder 13 is covered with an outer cylinder cover part 14A that covers the outer cylinder 13A and an inner cylinder 13B. End cap 1 consisting of inner cylinder lid part 14B
4, and the end cap 14 is integrally formed with the mounting portion 9, which serves as a connection portion to the vehicle chassis 2 side. Further, a rod guide 15 is provided on the other end side of the cylindrical body 13.
The other ends of the outer cylinder 13A and the inner cylinder 13B are covered. A cap 16 is screwed onto the other end of the cylindrical body 13, and the rod guide 15 is positioned in the axial direction while being held between the cap 16 and the inner cylinder 13B.

A piston 17 is slidably inserted into the inner cylinder 13A, and a piston rod 1 is attached to the piston 17.
8 is fixed at one end. The other end of the piston rod 18 passes through the rod guide 15 and the cap 16 and protrudes to the outside, and the mounting portion 10 that connects to the vehicle body 1 is integrally formed at its tip. ing. Here, the inside of the inner cylinder 13B is defined by the piston 17 into two oil chambers A and B, and a reservoir chamber C is formed between the inner cylinder 13B and the outer cylinder 13A. Oil liquid and air are sealed in the reservoir chamber C, and when the piston rod 18 enters the inner cylinder 13B, the air in the reservoir chamber C is compressed and the piston rod 18
A compensatory action is performed for the entry volume.

Further, the piston 17 is provided with passages 19, 19 that communicate between the oil chambers A and B.
A check valve 20 that allows oil to flow only from the oil chamber B to the oil chamber A is provided. On the other hand, in the inner cylinder lid portion 14B of the end cap 14, there are passages 21, 21 that communicate the oil chamber B and the reservoir chamber C.
A check valve 22 is provided in each passage 21 to allow oil to flow only from the reservoir chamber C to the oil chamber B.

23 is the inner cylinder cover part 14B and the outer cylinder 5 cover part 1.
4A, the oil passage 23
communicates with each of the passages 21 on one side, and communicates with a pipe 26, which will be described later, on the other side. 24 is located between the piston rod 18 and the rod guide 15,
An oil passage 25, which is bored in the axial direction of the rod guide 15 and communicates with the oil chamber A, is formed in the rod guide 15 so as to communicate with the oil passage 24 via a damping force adjustment valve mechanism 29, which will be described later. oil passage, 2
Reference numeral 6 indicates a pipe connected to the end cap 14 at one end and the rod guide 15 at the other end in order to communicate the oil passage 25 with the oil passage 23, and the pipe 26 connects the inner cylinder 13B and the outer cylinder 13A. An opening 26A extending in the axial direction between the reservoir chambers C and permanently communicating with the reservoir chamber C is provided at the intermediate portion thereof. In this way, the oil chamber A and the oil chamber B are connected to the outer cylinder 1 by the oil passages 23, 24, 25 and the pipe 26.
An oil passage communicating via 3A is configured.

On the other hand, 27 is a throttle passage bored in the radial direction of the inner cylinder 13B and communicating the oil chamber A with the oil passage 25;
The throttle passage 27 directs the oil in the oil chamber A to the oil chamber B through the oil passage 25 and pipe 26 when the piston rod 18 is extended, and through the oil passage 25 and pipe 2 when the piston rod 18 is contracted.
6 from the opening 26A to the reservoir chamber C, and in the low speed range of the piston 17, the oil fluid communicating with the throttle passage 27 generates a predetermined large damping force F (see FIG. 5). It's becoming like that. Reference numeral 28 denotes a large diameter hole drilled in the rod guide 15 in the radial direction, and an inner casing 30 of a damping force adjustment valve mechanism 29, which will be described later, is fitted into the large diameter hole 28.

Next, reference numeral 29 denotes a damping force adjustment valve mechanism interposed between the oil passages 24, 24, and the main body of the valve mechanism 29 is an inner casing 30 whose tip side is fitted into the large diameter hole 28 of the rod guide 15. and the inner casing 3 is fitted onto the base end side of the inner casing 30.
0, and a cover ring 33 that covers the base end side of the outer casing 31 via a cover body 32. The inner casing 30 is provided with oil passages 30A, 30B spaced apart from each other in the radial direction, and oil chambers 30C, 30D spaced apart from each other in the axial direction. 30D, and the oil passage 30B is constantly connected to the oil chamber 30C and the oil passage 25. Further, the outer casing 31 is provided with an air pressure introduction hole 31A, and the air pressure introduction hole 31A communicates with a pressure chamber D defined between diaphragms 35 and 42, which will be described later.

Reference numeral 34 denotes a stepped valve member that penetrates the oil chambers 30C and 30D and is slidably inserted in the inner casing 30 in the axial direction, and the distal end side of the valve member 34 has a small diameter portion. A pressure receiving portion 34A is provided at the tip of this small diameter portion to receive the hydraulic pressure in the oil passage 24 and displace the valve member 34 downward in the axial direction. Further, an oil chamber 30C is provided in the large diameter portion of the valve member 34.
An axial longitudinal groove 34B is provided that permanently communicates with the axially extending groove 34B. The vertical groove 34B is located apart from the pressure receiving part 34A, and its lower end is rounded and has a throttle part 34C for generating a damping force that opens and closes the oil passage according to the axial displacement of the valve member 34. It's summery.
Here, when the pressure receiving part 34A receives the hydraulic pressure in the oil passage 24 and the valve member 34 is displaced downward in the axial direction, the throttle part 34C communicates with the oil chamber 30D, and the oil passage 24, The oil in the oil chamber 30A, that is, the oil in the oil chamber A, is caused to flow from the oil chamber 30C to the oil passages 30B and 25 through the vertical groove 34B, and then into the oil chamber B and the reservoir chamber C, and A desired resistance force is applied to the oil passing through the 34C, and a desired damping force is generated.

35 is a mounting member 3 on the proximal end side of the valve member 34.
6. A small diameter diaphragm serving as a first movable partition whose inner circumferential side is fixed by a lock nut 39 via a mounting plate 37 and a washer 38, and the outer circumferential side of the diaphragm 35 is attached to the proximal end surface of the inner casing 30. It is fixed by a mounting ring 41 via a washer 40, and the mounting ring 41 is screwed onto the outer casing 31. 42 is a large-diameter diaphragm as a second movable partition that is arranged to face the small-diameter diaphragm 35 and defines the pressure chamber D between it and the diaphragm 35;
The outer peripheral side of the diaphragm 42 is connected to the outer casing 3
1 and the outer periphery of the lid 32, and the inner periphery is held between the mounting member 43 and the mounting plate 44.
The screws 45 are used to hold the screws 45 between them. Here, the mounting member 43 and the diaphragm 42 are attached to the second
constitutes a movable partition wall, and the upper surface of its central portion is connected to the valve member 3.
It is in contact with the lower end surface of 4 and can be separated from it. and,
A circular groove 43A is provided in the center of the mounting member 43, and the circular groove 43A is spline-coupled to an annular protrusion 32A provided upright in the center of the lid 32, so as to prevent the mounting member 43 from moving in the axial direction. It is designed to guide you.

Further, 46 indicates the circular groove 43A, the annular protrusion 3
2A, the spring 46 urges the valve member 34 upward in the axial direction via the mounting member 43 with a relatively large spring load. Reference numerals 47 and 48 denote ventilation holes, and 49 a sealing member for airtightly sealing the periphery of the valve member 34. The valve member 3 is
It is becoming more closely related to 4. 50 is a ball that closes the upper end of the oil passage 30B, and 51 is a bolt that fixes the inner casing 30 and outer casing 31 to the outer cylinder 13A and the rod guide 15 via washers 52.

Thus, the damping force adjustment valve mechanism 29 is constituted by the inner casing 30, the outer casing 31, the lid 32, the valve member 34, the diaphragms 35, 42, the pressure chamber D, the spring 46, etc. Air pressure P adjusted to a desired pressure from the controller 12 is supplied to the air pressure introduction hole 31 in D.
It is designed to be introduced via A. When the inside of the pressure chamber D reaches a pressure state based on the air pressure P, the diaphragm 35 urges the valve member 34 upward in the axial direction with a force corresponding to the air pressure P, and the oil passage 2
The valve member 34 is prevented from being displaced downward in the axial direction due to the pressure receiving portion 34A receiving the hydraulic pressure in the valve member 4. As a result, the axial displacement of the valve member 34 is controlled according to the air pressure P, and the oil chamber 3
The state of communication, that is, the degree of opening of the constricted portion 34C with 0D is adjusted, and the damping force generated in the constricted portion 34C is adjusted.

In the figure, 53 is a passage for returning the oil leaking from between the rod guide 15 and the piston rod 18 to the reservoir chamber C, 54 is a sealing member that airtightly seals the circumference of the piston rod 18, and 55 and 56 are one end side of the piston rod 18. A double nut for fixing the piston 17 to the double nut 55,
56 is set in the locked state by bending the end of the washer 57. In addition, the inner cylinder 1
The cross-sectional area of the piston rod 3B is set at a ratio of 2:1 to the cross-sectional area of the piston rod 18, so that the damping force characteristics during the extension stroke and the contraction stroke are the same.

Next, the operation of the lateral movement shock absorber constructed as described above will be explained with reference to FIGS. 4 and 5.

For example, assuming that a railway vehicle is running on a track R (see FIG. 1), air pressure P is supplied to a pressure chamber D via a sensor 11 and a controller 12. Here, since the large-diameter diaphragm 42 receives this air pressure P with a large pressure receiving area together with the mounting member 43, these are displaced downward against the spring 46, and the mounting member 43 is connected to the valve member 34.
spaced from the proximal end of the Therefore, the valve member 34 is urged upward in the axial direction by the small-diameter diaphragm 35 by a force given by the product of the air pressure P and the pressure-receiving area of the diaphragm 35.
When the hydraulic pressure in the oil chamber A and the oil passage 24 increases during the extension and contraction strokes of the piston rod 18, the downward displacement in the axial direction caused by receiving this hydraulic pressure in the pressure receiving portion 34A causes the air pressure P to increase. The opening degree when the throttle part 34C communicates with the oil chamber 30D is adjusted accordingly, and the damping force generated in the throttle part 34C is increased in accordance with the air pressure P, as shown in FIG. .

That is, when a railway vehicle runs on a place where the track R is curved or undulating, and furthermore when the running speed of the vehicle increases, if the vehicle body 1 begins to vibrate in the left-right direction, the vehicle body 1 The sensor 11 detects displacement, acceleration, speed, etc. due to this vibration, and outputs an electric signal S corresponding to this to the controller 12. Then, the controller 12 supplies the air pressure P (for example, about 2 kg/cm ² ) in a pressure state adjusted according to the electric signal S to the pressure chamber D, and the urging force of the diaphragm 35 to the valve member 34 is increased. is set to a relatively large value. For this reason,
As the piston rod 18 expands and contracts,
Even if the hydraulic pressure in the oil chamber A and the oil passage 24 becomes considerably high, the downward displacement of the valve member 34 in the axial direction can be suppressed, and the opening degree of the throttle part 34C can be made considerably small. It is possible to impart a large resistance force to the oil passing through the damping force characteristics and obtain damping force characteristics as shown as characteristics P ₂ and P ₃ in FIG.

On the other hand, when the vibration of the vehicle body 1 becomes even larger, an even higher value of air pressure P is supplied from the controller 12 to the pressure chamber D by the electric signal S from the sensor 11, and as shown as characteristic P ₄ in FIG. This provides excellent damping force characteristics. Conversely, when the vibration of the vehicle body 1 becomes smaller, the electric signal S from the sensor 11 causes a low value of air pressure P to be applied to the controller 1.
2 to the pressure chamber D, and the characteristics are shown in FIG.
A damping force characteristic as shown as P ₁ is obtained.

In this way, by increasing or decreasing the air pressure P according to the vibration of the vehicle body 1, the damping force can be adjusted as shown in the characteristics P ₁ , P ₂ , P ₃ , and P ₄ shown in FIG. 5, improving the ride comfort of the vehicle. can be done.

By the way, when a failure or the like occurs in the piping system for the air pressure P, and the air pressure P at the desired pressure cannot be supplied to the pressure chamber D, and the pressure chamber D becomes atmospheric pressure, the spring load of the spring 46 causes the installation to be stopped. The member 43 is pushed back, and the mounting member 43 comes into contact with the proximal end (lower end surface) of the valve member 34 as shown in FIG. As a result, a damping force corresponding to the spring load of the spring 46 due to the oil flowing through the constriction portion 34C is obtained as a large damping force characteristic such as the characteristic P ₄ shown in FIG. Sometimes a relatively large damping force can be generated to provide a fail-safe function.

Therefore, according to this embodiment, the air pressure P can be supplied to the pressure chamber D at a value that is adjusted according to the vibration state of the vehicle body 1, that is, the state of the track R and the running speed, and the air pressure P that corresponds to the pressure of this air pressure P can be supplied to the pressure chamber D. As a result, the valve member 34 can be biased upward in the axial direction with the same biasing force, and as a result, the damping force characteristics can be adjusted as desired, ensuring optimal ride comfort, and even when the vehicle travel speed is increased. . Furthermore, if a failure or the like occurs in the piping system for the air pressure P, the damping force can be adjusted by the spring load of the spring 46, and a fail-safe structure can be achieved.

In addition, in this embodiment, the valve member 34 is provided with a pressure receiving portion 34.
Since the pressure receiving portion 34A and the throttle portion 34C are provided apart from each other, the pressure receiving portion 34A is connected to the oil passage 24, that is, the oil chamber A.
The valve member 34 can be displaced downward in the axial direction by reliably receiving the hydraulic pressure inside the valve member 34.
It is possible to eliminate a situation in which the axial displacement of the cylinder is affected by the oil passing through the constricted portion 34C.

In the above embodiment, the diaphragms 35 and 42 are used to define the pressure chamber D, but other movable partitions such as a piston or a bellows may be used instead.

Further, in the above embodiments, the explanation has been given by taking the lateral movement shock absorber of a railway vehicle as an example, but the present invention is not limited to this, and can be applied to a shock absorber other than a railway vehicle, a vertical movement shock absorber, etc.
It can also be applied to shock absorbers for industrial machinery, etc., where the damping force characteristics need to be adjusted as desired.

[Effect of idea]

As detailed above, according to the present invention, the valve member is provided with a throttle portion for generating a damping force that opens and closes the oil passage in accordance with the axial displacement of the valve member, spaced apart from the pressure receiving portion of the valve member, The valve member is displaced to one side in the axial direction by the pressure in the oil passage received by the pressure receiving part, and gas pressure is supplied from the outside to the pressure chamber defined by the first movable partition wall and the second movable partition wall. By doing so, the valve member is urged toward the other side in the axial direction, and by adjusting this gas pressure, the generated damping force can be made variable, so that vibrations of the vehicle, etc. to which the hydraulic shock absorber is installed can be made variable. By adjusting the gas pressure according to the state, it is possible to appropriately generate a damping force according to the vibration state, ensuring optimal ride comfort, and making it possible to cope with higher speeds of the vehicle. In addition, since the pressure-receiving part and the throttle part are provided in the valve member alternately and spaced apart, the valve member can be pivoted according to the hydraulic pressure received by the pressure-receiving part without being affected by the oil passing through the throttle part. It can be displaced in one direction, and the damping force can be reliably adjusted according to the gas pressure.

Furthermore, when the supply of gas pressure to the pressure chamber is stopped, the valve member can be biased toward the other side in the axial direction by the spring load of the spring that biases the second movable partition wall toward the pressure chamber, and based on this spring load, the valve member can be biased toward the other side in the axial direction. By generating a relatively large damping force, a reliable fail-safe function can be provided.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a state in which a shock absorber according to an embodiment of the present invention is applied as a lateral motion shock absorber for a railway vehicle, FIG. 2 is a longitudinal sectional view of the shock absorber shown in FIG. 1,
3 is a longitudinal sectional view of the damping force adjusting valve mechanism shown in FIG. 2, FIG. 4 is a diagram showing the relationship between air pressure and damping force, and FIG. 5 is a damping force characteristic diagram. 8...Hydraulic shock absorber, 13A...Outer cylinder, 13B...
... Inner cylinder, 17 ... Piston, 18 ... Piston rod, 2324, 25 ... Oil passage, 26 ... Pipe, 29 ... Damping force adjustment valve mechanism, 30 ... Inner casing, 31 ... Outer casing, 32 ……
Lid body, 34...Valve member, 34A...Pressure receiving part, 34
C...Aperture part, 35, 42...Diaphragm,
A, B...oil chamber, C...reservoir chamber, D...pressure chamber, P...pneumatic pressure.

Claims (1)

[Scope of utility model registration request] an outer cylinder, an inner cylinder disposed within the outer cylinder, a piston that is slidably inserted into the inner cylinder and defines the inside of the inner cylinder into two oil chambers, and one end of which is connected to the piston. a piston rod that is attached and whose other end protrudes outward from the inner and outer cylinders, an oil passage that communicates the two oil chambers through the outer cylinder, and a damping force adjustment provided in the middle of the oil passage. In the damping force adjustable hydraulic shock absorber, the damping force adjusting valve mechanism includes a valve member displaceable in the axial direction and provided in the middle of the oil passage, and a valve member disposed on the distal end side of the valve member. provided,
a pressure receiving part that receives pressure in the oil passage and displaces the valve member to one side in the axial direction; a throttle part for generating a damping force that changes the degree of opening with respect to the oil passage; and a constriction part provided on the proximal end side of the valve member,
a first movable partition that urges the valve member toward the other side in the axial direction when gas pressure is applied; a second movable partition wall provided opposite to the first movable partition wall so as to be able to come into contact with and separate from the partition wall; a pressure chamber defined between each of the movable partition walls and to which gas pressure is supplied from the outside; and the pressure chamber. The second movable partition wall is always urged toward the side, and when the supply of gas pressure to the pressure chamber is stopped, the valve member is urged to the other side in the axial direction via the second movable partition wall. A damping force adjustable hydraulic shock absorber comprising a spring.