JPH09217775A - Damping device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a damping device capable of obtaining large damping force and obtaining suitable damping force according to the wide frequency range, in the damping device to be used for damping of free vibration in a vibration system or restriction of resonance of forced vibration. SOLUTION: Viscous fluid is filled in a cylinder 1, openings 10 are respectively and projectingly provided on the peripheral walls of a first chamber 5 and a second chamber 6 in the cylinder partitioned by a piston 2 to be reciprocated in the cylinder, and a communication pipe 4 connected to the openings and for communicating the first chamber with the second chamber are provided. When the movement of an external member is transmitted to the piston 2 through a cylinder rod 3, viscous fluid is moved through a fluid passage formed by the communication pipe 4. The kinetic energy is absorbed by the dynamic pressure resistance by the orifice effect and the viscous resistance of fluid to be moved in the communication pipe by increase of the speed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a structure
The present invention relates to a so-called damper, which is used for a vibration system of general machinery, railway vehicles, automobiles, aircrafts, measuring instruments, and the like, for damping free vibrations and suppressing resonance of forced vibrations.

[0002]

2. Description of the Related Art As a damper that absorbs energy of a vibration system and gives a damping force, a fluid dynamic pressure resistance is used,
There are those that use the viscous resistance of fluid, those that utilize solid friction, and those that utilize electromagnetic force. Among them, those using fluid, that is, those using dynamic pressure resistance or those using viscous resistance are widely used because they can be manufactured at low cost and have excellent durability.

FIG. 7 is a schematic sectional view showing an example of a hydraulic damper utilizing the dynamic pressure resistance of fluid. This damper includes a cylinder 101 filled with a fluid and the cylinder 101.
It has a piston 102 that divides the inside into a first chamber 105 and a second chamber 106, and this piston 102 is provided with a communication port 102a (orifice) between the first chamber 105 and the second chamber 106. . When the piston 102 reciprocates in the cylinder 101, the filled fluid moves between the first chamber 105 and the second chamber 106 through the communication port 102a, and the pressure difference generated on both sides of the piston 102 is reduced. It becomes a resistance force against the force to move the piston 102 and absorbs energy. That is, the turbulent flow is generated in the fluid passing through the communication port 102a to absorb the energy.

On the other hand, a device utilizing viscous resistance has a structure as shown in FIGS. 8 and 9, for example. FIG.
In the device shown in FIG. 2, the plate-like members 111 and 112 are arranged so as to face each other with a gap, and the viscous fluid 113 is filled in the gap. The plate-like member 111 relatively moves in a direction parallel to the facing surface. At this time, the shear resistance force of the viscous fluid 113 acts to absorb energy. Further, in the device shown in FIG. 9, the disk-shaped member 121 is arranged so as to face the fixed plate 122, and the viscous fluid 1 is placed in the gap between them.
23, and absorbs energy by the resistance force of the viscous fluid 123 when the disk-shaped member 121 rotates around the central axis. That is, these generate a laminar flow in the fluid filled between the members that move relative to each other, and the viscous resistance force absorbs the energy.

[0005]

However, the damper as described above has the following problems. In the damper using the dynamic pressure resistance of the fluid as shown in FIG. 7, the damping force is proportional to the square of the relative speed between the piston and the cylinder. For this reason, the energy absorbed in the low frequency region decreases rapidly, and it is difficult to cope with a wide frequency region. For such problems, it is known to use a damping device by switching depending on the frequency domain, or to use a pressure regulating valve that changes the opening area of the orifice, but the device or the method of use is complicated and the cost is large. Becomes

On the other hand, the device using the viscous resistance as shown in FIG. 8 or 9 has a feature that the damping force is proportional to the speed, but the device becomes large in size to obtain a large damping force. Further, it is difficult to adjust the damping force.

The invention according to the present application has been made in view of the above problems, and an object thereof is to provide a damping device (damper) capable of easily obtaining a large damping force in a wide frequency range. Is to provide.

[0008]

In order to solve the above problems, the invention according to claim 1 provides a cylinder filled with a viscous fluid, a piston reciprocating in the cylinder, and a partition by the piston. Provided is a damping device having fluid passages which are continuous with openings provided in the peripheral walls of the first chamber and the second chamber in the cylinder and which communicate the first chamber and the second chamber.

According to a second aspect of the present invention, in the damping device according to the first aspect, the fluid passage is formed by a communication pipe attached to the outside of the cylinder.

According to a third aspect of the present invention, in the damping device according to the first aspect, the fluid passage is formed in a peripheral wall of the cylinder.

According to a fourth aspect of the present invention, in the damping device according to the third aspect, the double cylinder is fitted so that the outer peripheral surface of the inner pipe and the inner peripheral surface of the outer pipe are pressed against each other. It has a structure, and the fluid passage is formed by a groove formed on at least one of an outer peripheral surface of the inner pipe and an inner peripheral surface of the outer pipe.

According to a fifth aspect of the present invention, in the damping device according to the fourth aspect, the fluid passage is formed in a spiral shape along a boundary surface between the outer pipe and the inner pipe of the cylinder. And

According to a sixth aspect of the present invention, in the damping device according to the first to fifth aspects, a spring member that applies a restoring force when relative displacement between the cylinder and the piston occurs. Shall have.

In the damping device according to the first or second aspect, the opening may be provided in the end wall of the cylinder or in the peripheral wall. Further, claim 1 to claim 5
In the damping device described above, the number of fluid passages that communicate the first chamber and the second chamber in the cylinder is not limited to one, and a plurality of fluid passages may be provided, and the cross-sectional shape, cross-sectional area, and the like are appropriately determined by design. be able to.

[Operation] Since the invention according to the present application has the above-mentioned configuration, it operates as follows. In the damping device according to claim 1, since the inside of the cylinder filled with the viscous fluid is partitioned by the piston into the first chamber and the second chamber, and the fluid passage that connects these is provided, the cylinder rod and the piston are When the cylinder moves relative to the cylinder by an external force, the viscous fluid in the cylinder moves between the first chamber and the second chamber through the fluid passage. At this time, a turbulent flow is generated by the introduction into the fluid passage and the ejection from the fluid passage, and the kinetic energy is absorbed by the orifice effect. Further, in the fluid passage, viscous resistance acts between the viscous fluid having an increased flow velocity and the wall surface. This viscous resistance follows Newton's viscosity law, and the kinetic energy is also absorbed by this resistance. Thus, not only the pressure difference due to the orifice effect but also the absorption of the kinetic energy due to the pressure difference due to the viscous resistance is added, and a large damping force is applied to the movement of the cylinder rod and the piston.

As described above, in this damping device, energy is absorbed by both the dynamic pressure resistance and the viscous resistance of the fluid, so the cross-sectional area, cross-sectional shape and length of the fluid passage, the viscosity of the viscous fluid, etc. By adjusting, the total amount of energy absorbed and the ratio of the amount of energy absorbed by the dynamic pressure resistance to the amount of energy absorbed by the viscous resistance can be easily adjusted. Therefore, a large damping force can be obtained even if the size is reduced, and the amount of energy absorbed by the viscous resistance can be increased to provide a damping device that effectively operates even in a low frequency region.

Further, in the damping device according to the second aspect, since the fluid passage is formed by the communication pipe provided outside the cylinder, the viscous resistance can be easily adjusted by adjusting the length of the pipe. It

On the other hand, in the damping device according to the third aspect, since the fluid passage is formed in the peripheral wall of the cylinder, it is not necessary to attach a communication pipe to the outside of the cylinder, and the pipe is connected while maintaining liquid tightness. This eliminates the need for a structure that improves durability and reliability.

In the damping device according to the fourth aspect, the cylinder has a double structure in which the inner pipe and the outer pipe are fitted together,
Since the fluid passage is provided at the boundary between the inner pipe and the outer pipe, a groove is formed on the outer peripheral surface of the inner pipe or the inner peripheral surface of the outer pipe, and these are fitted to each other so that the inner wall of the cylinder is not covered. It is possible to easily form the fluid passage.

Further, in the damping device according to claim 5,
Since the fluid passage is provided spirally in the peripheral wall of the cylinder, the extension of the fluid passage can be freely set,
It is also possible to set a large viscous resistance.

Further, in the damping device according to the sixth aspect of the invention, since the damping member is provided with the spring member for applying the restoring force to the relative displacement between the cylinder and the piston, the damping force and the restoring force are applied to the external motion member. can do.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a damping device which is an embodiment of the invention described in claim 1 or 2. This damping device includes a cylinder 1 filled with a viscous fluid, and a piston 2 that partitions the interior of the cylinder 1 into a first chamber 5 and a second chamber 6 and that reciprocates in the axial direction.
And a cylinder rod 3 that transmits an external force to this piston 2.
And a communication pipe 4 that connects the first chamber 5 and the second chamber 6 in the cylinder 1.

The cylinder rod 3 penetrates one end wall 1a of the cylinder 1 and has one end protruding to the outside, and an attaching portion 3a for connecting with an external fixing member or a moving member is formed at this end. Has been done. On the other hand, the other end 3b of the cylinder rod penetrates the partition wall 1b of the cylinder 1 and projects into the waiting room 7. A seal member 8 that allows the cylinder rod 3 to reciprocate and prevents the viscous fluid from flowing out is interposed between the cylinder rod 3 and the end wall 1a or the partition wall 1b that penetrates the cylinder rod 3. The cylinder 1 has two openings 10 and 10 on the peripheral wall thereof, and projections 11 and 11 for connecting the communication pipe 4 are provided on the outer peripheral surface of the openings.
Is provided. Further, a mounting portion 1d for connecting to an external moving member or a fixed member is formed on the end wall 1c of the cylinder 1 on the side where the waiting room 7 is provided.

The communicating pipe 4 is brought into contact with the protrusions 11, 11 provided on the outer peripheral surface of the cylinder 1, and can be firmly connected to the protrusions 11, 11 by tightening nuts 12, 12. The viscous fluid is allowed to flow between the first chamber 5 and the second chamber 6 through the openings 10 provided in the first chamber 1. In addition, reference numeral 13 shown in FIG.
Shows a buffer chamber for accommodating the expansion due to the temperature rise of the fluid. Although this buffer chamber is provided so as to communicate with the second chamber of the cylinder, another buffer chamber may be provided so as to communicate with the first chamber. By providing the two buffer chambers in this manner, when a large acceleration acts between the piston 2 and the cylinder 1, the first chamber 5 and the second chamber
It is possible to prevent the pressure difference from the chamber 6 from becoming excessive. Further, reference numeral 14 denotes an air vent hole 1 for preventing the atmospheric pressure in the waiting room 7 from fluctuating due to the movement of the cylinder rod 3.
4 is shown.

In such a damping device, when a relative motion occurs between the cylinder 1 and the piston 2 due to an external force, the viscous fluid in the cylinder 1 passes through the communication pipe 4 from the opening 10 provided in the peripheral wall and passes through the cylinder 1. It moves between the first chamber 5 and the second chamber 6 inside. At this time, the kinetic energy is absorbed by the dynamic pressure resistance due to the fluid moving from the opening 10 through the communication tube and the viscous resistance of the fluid whose speed has been amplified in the communication tube 4. In this way, since the motion is damped by both the effect of the dynamic pressure resistance of the fluid and the effect of the viscous resistance in the communication pipe, a large damping force can be obtained. Also,
The communication pipe 4 can be exchanged according to the frequency of the external force, and the ratio of the effect of the dynamic pressure resistance and the effect of the viscous resistance can be adjusted to give an appropriate damping force to a wide range of frequencies. be able to.

FIG. 2 is a schematic sectional view showing a damping device according to an embodiment of the invention described in claim 1 or claim 3. In this damping device, a part of the cylinder 21 is continuously thickened in the axial direction, a fluid passage 24 is provided in the peripheral wall of this part, and the first chamber 25 and the second chamber 25 in the cylinder 21 are provided.
It is adapted to communicate with the chamber 26. This cylinder 2
The structure of the other parts of 1 and the structure of the piston 22 and the cylinder rod 23 which this damping device has are the same as the damping device shown in FIG. The fluid passage 24 is formed by forming a deep hole in the axial direction from one end of the cylinder 21, connecting the deep hole to the inside of the cylinder at two locations, and closing the hole near the end. You can The holes may be closed by back-filling with metal pieces by press fitting, or by embedding a screw or the like.

Even in such a damping device, energy is absorbed by both the dynamic pressure resistance and the viscous resistance of the fluid, and a large damping force can be obtained. In addition, the characteristics of the damping force with respect to the frequency can be adjusted by adjusting the diameter of the fluid passage 24 and the like. Further, since it is not necessary to provide the fluid passage outside the cylinder, it is possible to improve durability and reliability and to reduce the external dimensions.

FIG. 3 shows claims 1, 3 or 4.
2 is a schematic cross-sectional view showing a damping device that is an embodiment of the invention described in FIG. In this damping device, the cylinder 31 has the inner tube 3
It has a double structure in which 1a and an outer pipe 31b are fitted together, and the outer peripheral surface of the inner pipe 31a and the inner peripheral surface of the outer pipe 31b are pressed against each other. The fluid passage 34 is formed by a groove cut in the axial direction of the outer peripheral surface of the inner pipe 31a and through holes 31c and 31d formed at both ends of the groove, and the inner pipe 31a and the outer pipe 31a are formed. Cylinder 3 when fitted with 31b
A pipe line that connects the first chamber 35 and the second chamber 36 in 1 is formed. The structure of the other parts of the cylinder 31 and the structure of the piston 32 and the cylinder rod 33 of this damping device are the same as those of the damping device shown in FIG.

With such a damping device, the same effect as that of the damping device shown in FIG. 2 can be obtained, and the fluid passage 34 can be easily formed in the peripheral wall of the cylinder 31. In the above damping device, the fluid passage 34 is formed by cutting a groove on the outer peripheral surface of the inner pipe 31a, but it may be formed by cutting a groove on the inner peripheral surface of the outer pipe 31b. Alternatively, grooves may be cut on both the outer peripheral surface of the inner tube 31a and the inner peripheral surface of the outer tube 31b, and the grooves may be fitted so that their positions match. Further, the fluid passage 34 is provided at one location in the circumferential direction, but a plurality of fluid passages may be provided.

FIG. 4 is a schematic sectional view of a damping device which is an embodiment of the invention described in claim 1, claim 3, claim 4 or claim 5. The cylinder 41 of this damping device has a structure in which an inner pipe 41a and an outer pipe 41b are fitted to each other as shown in FIG. 3, but a fluid passage 44 is formed in a spiral shape along the peripheral wall of the cylinder 41. Has been done. The other structure of this damping device is the same as that of the damping device shown in FIG.
Even with such a damping device, the same effect as that of the damping device shown in FIG. 3 can be obtained, and the length of the fluid passage 44 can be appropriately set by setting the pitch of the spiral.

FIG. 5 is a schematic sectional view showing a damping device according to an embodiment of the invention described in claim 6. This damping device has the same cylinder 51 and piston 5 as the device shown in FIG.
2, a cylinder rod 53, a fluid passage 54 and the like, and coil springs 57 and 58 are housed in the first chamber 55 and the second chamber 56 in the cylinder 51, respectively.
These coil springs have an outer diameter slightly smaller than the inner peripheral surface of the cylinder 51, are inserted between the end wall 51a of the cylinder 51 and the piston 52, and between the piston 52 and the partition wall 51b, and the piston 52 is A restoring force is applied when the cylinder 51 is displaced in the axial direction. With such a damping device, as with the damping device shown in FIG. 2, it is easy to cope with the fact that a large damping force can be obtained in both the high frequency region and the low frequency region, and the external damping A restoring force can be applied to the moving member.

FIG. 6 is a schematic sectional view showing a damping device according to another embodiment of the invention described in claim 6. In this damping device, a first brim member 71 is provided near one end of a cylinder rod 63 protruding outside the cylinder 61, and a first brim member 71 is provided between the first brim member and the end wall 61 a of the cylinder 61. The coil spring 73 is inserted. Further, the cylinder rod 6 protruding into the waiting room 67 of the cylinder 61
A second collar-shaped member 72 is provided at the other end of the second coil spring 7, and the second coil spring 7 is provided between the collar-shaped member 72 and the end wall 61c.
4 is inserted. The other structure of this damping device is the same as that of the device shown in FIG. Also in such a damping device, a large damping force and restoring force can be applied to the moving member as in the device shown in FIG.

The damping device shown in FIGS. 5 and 6 uses two coil springs to apply a restoring force to the bidirectional displacement. However, one coil spring is used to displace the unidirectional displacement. The restoring force may be applied only to, or the restoring force for the bidirectional displacement may be applied by the restoring force for the compression deformation and the tensile deformation of one coil spring.

The damping device shown in FIGS. 5 and 6 is
Although the fluid passage that connects the first chamber and the second chamber of the cylinder is provided in the peripheral wall of the cylinder, the damping device as shown in FIG. 1, FIG. 3 or FIG. 4 also uses a spring member. Similarly, a damping device that applies a restoring force can be used.

[0035]

As described above, in the damping device of the invention according to the present application, energy is absorbed by both the dynamic pressure resistance of the fluid and the viscous resistance in the fluid passage to damp the motion. Therefore, a large damping force can be obtained, and a viscous resistance proportional to the motion velocity and a dynamic pressure resistance proportional to the square of the motion velocity are appropriately combined to obtain a damping device corresponding to the frequency region of the motion. You can

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a damping device according to an embodiment of the invention described in claim 1 or claim 2.

FIG. 2 is a schematic sectional view showing a damping device according to an embodiment of the invention described in claim 1 or claim 3.

FIG. 3 is a schematic cross-sectional view showing a damping device which is an embodiment of the invention according to claim 1, claim 3 or claim 4.

FIG. 4 is a schematic cross-sectional view showing a damping device which is an embodiment of the invention described in claim 1, claim 3, claim 4 or claim 5.

FIG. 5 is a schematic sectional view showing a damping device according to an embodiment of the invention described in claim 6.

FIG. 6 is a schematic cross-sectional view showing a damping device according to another embodiment of the invention as set forth in claim 6.

FIG. 7 is a schematic sectional view showing a conventional damping device.

FIG. 8 is a schematic cross-sectional view showing a conventional damping device that utilizes the viscous resistance of a fluid.

FIG. 9 is a schematic cross-sectional view showing another example of a conventional damping device that utilizes the viscous resistance of a fluid.

[Explanation of symbols]

1, 21, 31, 41, 51, 61 Cylinder 2, 22, 32, 42, 52, 62 Piston 3, 23, 33, 43, 53, 63 Cylinder rod 4 Communication pipe 24, 34, 44, 54 Fluid passage 5 , 25, 35, 55 1st chamber in cylinder 6, 26, 36, 56 2nd chamber in cylinder 7, 67 Waiting room 8 Seal member 10 Opening 11 Protrusion 12 Tightening nut 13 Buffer chamber 14 Air vent hole 57, 58 Coil spring 71 First Collar Member 72 Second Collar Member 73, 74 Coil Spring

Claims (6)

[Claims] 1. A cylinder filled with a viscous fluid, a piston that reciprocates in the cylinder, and openings provided in the peripheral walls of the first chamber and the second chamber in the cylinder that are partitioned by the piston. And a fluid passage that connects the first chamber and the second chamber to each other. 2. The damping device according to claim 1, wherein the fluid passage is formed by a communication pipe attached to the outside of the cylinder. 3. The damping device according to claim 1, wherein the fluid passage is formed in a peripheral wall of the cylinder. 4. The damping device according to claim 3, wherein the cylinder has a double structure in which the outer peripheral surface of the inner pipe and the inner peripheral surface of the outer pipe are fitted in pressure contact with each other, The damping device, wherein the passage is formed by a groove cut on at least one of the outer peripheral surface of the inner pipe and the inner peripheral surface of the outer pipe. 5. The damping device according to claim 4, wherein the fluid passage is formed in a spiral shape along a boundary surface between the outer pipe and the inner pipe of the cylinder. . 6. The damping device according to claim 1, further comprising a spring member that applies a restoring force when a relative displacement between the cylinder and the piston occurs. apparatus.