JP4890334B2 - Hydraulic shock absorber - Google Patents

Description

  The present invention relates to a hydraulic shock absorber, and more particularly to an improvement of a so-called horizontal hydraulic shock absorber.

  There have been various proposals so far for hydraulic shock absorbers that are used in a so-called horizontal position such as rolling prevention dampers in railway vehicles and vibration damping dampers in buildings. Discloses a proposal of a hydraulic shock absorber having an outflow pipe for allowing hydraulic oil from the inner cylinder to flow into the reservoir chamber.

  That is, the hydraulic shock absorber disclosed in Patent Document 1 is formed in a double cylinder type having an outer cylinder outside the inner cylinder and a reservoir chamber between the inner cylinder and the outer cylinder. The body is inserted in a retractable manner and is slidably received in the inner cylinder, and the piston body defining the rod side chamber and the piston side chamber is held in the inner cylinder by the tip of the rod body. .

  In this hydraulic shock absorber, the piston body has a check valve, and this check valve is a hydraulic oil from the piston side chamber during the so-called contraction operation in which the rod body is immersed in the inner cylinder. Is allowed to flow into the rod side chamber, but the reverse flow is prevented.

  Further, in this hydraulic shock absorber, a so-called head portion that allows the rod body to pass through the shaft core portion while closing the one end opening of the inner cylinder and the one end opening of the outer cylinder is connected to the reservoir chamber for hydraulic oil from the rod side chamber. It has a check valve that allows outflow but prevents the reverse flow, and further, closes the other end opening of the inner cylinder and the other end opening of the outer cylinder. It has a check valve that allows the inflow of air but prevents the reverse flow.

  Further, in this hydraulic shock absorber, an outflow pipe made of a pipe body protrudes from the head portion, that is, the distal end is opened to the reservoir chamber while the base end portion is connected to the head portion, and the inner side is the reservoir. It has an outflow pipe communicating with the chamber and the downstream side of the check valve disposed in the head portion.

  Therefore, in the hydraulic shock absorber disclosed in Patent Document 1, hydraulic oil from the rod side chamber flows through the check valve provided in the head portion and flows out into the reservoir chamber when the telescopic operation is performed. At this time, the hydraulic oil flowing out from the head portion toward the reservoir chamber passes through the outflow pipe connected to the head portion and flows out into the reservoir chamber.

  Therefore, the hydraulic oil that flows out from the head portion toward the reservoir chamber does not flow out from the head portion into the reservoir chamber in an unconstrained state, and therefore, the aeration phenomenon in which air is mixed into the hydraulic fluid that flows into the reservoir chamber. It is effective in preventing the expression of.

  On the other hand, in the hydraulic shock absorber disclosed in Patent Document 2, the basic configuration as a hydraulic shock absorber is the same as before, but the outflow pipe disclosed in Patent Document 1 is not provided. And it is supposed that it has the inflow pipe projected in the bottom part.

  That is, in the hydraulic shock absorber disclosed in Patent Document 2, the inflow pipe is formed of a pipe body, like the above-described outflow pipe, and the distal end is opened to the reservoir chamber while the base end portion is connected to the bottom portion. The inside is communicated with the reservoir chamber and the upstream side of the check valve provided at the bottom portion.

Therefore, in the hydraulic shock absorber disclosed in Patent Document 2, it is originally used in a horizontal position, but it is assumed that the bottom part is placed higher than the head part for estimation. Therefore, even if the oil surface faces the end surface of the bottom portion, that is, the end surface where the inflow tube protrudes, the inflow tube where the tip will be present in the hydraulic oil is formed in the bottom portion. Therefore, it is possible to prevent a situation in which air enters the bottom portion and air is mixed into the hydraulic oil.
JP-A-10-252799 (refer to paragraphs 0013 to 0016, 0022 to 0024 and FIG. 1 in the specification) Japanese Unexamined Patent Publication No. 2000-18308 (see paragraphs 0003 to 0006, 0022 to 0024 and FIG. 1 in the specification)

  However, each of the proposals disclosed in Patent Document 1 and Patent Document 2 described above has their merits and demerits. When this is realized, there is a concern that each problem may be pointed out.

  In other words, in the hydraulic shock absorber disclosed in Patent Document 1, when the bottom portion is higher than the head portion, the bottom portion does not have an inflow pipe. There is a risk of inconvenience of mixing air with hydraulic fluid.

  Since the hydraulic shock absorber disclosed in Patent Document 2 does not have an outflow pipe, the hydraulic oil that flows out from the head portion toward the reservoir chamber flows out into the reservoir chamber in an unrestricted state. Therefore, the aeration phenomenon in which air is mixed into the hydraulic oil flowing out to the reservoir chamber cannot be prevented in advance.

  Therefore, in the present invention, a hydraulic shock absorber having both the outflow pipe and the inflow pipe described above is proposed, but on the other hand, even if it has the outflow pipe, the vibration to the bottom portion is about. In the high speed range where the speed is 0.2 m / sec or higher, the outflow speed of the hydraulic oil from the outflow pipe also increases, so that it is impossible to effectively prevent the occurrence of aeration phenomenon in which air is mixed in the reservoir chamber. There is a fear.

  The present invention was devised in view of the above-described circumstances, and its object is to prevent the occurrence of aeration and reduce the chance of air being mixed into the hydraulic oil as much as possible. At least, it is easy to ensure the operability of the hydraulic shock absorber, and to provide a hydraulic shock absorber that is optimal for expecting an improvement in its versatility.

To achieve the above object, the configuration of a hydraulic shock absorber according to the invention, having a reservoir chamber between the inner tube and the outer tube, closing one end opening of the end openings and the outer tube of the inner tube a head portion having a bottom portion for closing the other end opening of the other open end and the outer tube of the inner tube, so as to project the head hydraulic oil of the reservoir chamber from within said inner cylinder has a outflow pipe which permits the passage towards a side, the hydraulic shock that is projected in the bottom portion comprising a inlet tube permitting passage into the inner cylinder of the hydraulic oil from the reservoir chamber in vessels, the opening to the vessel chamber to the tip of the outflow tube communicating with the bottom portion is formed in the reservoir chamber and the fraction made while being within the inner cylindrical, the base end of the inflow pipe to the vessel chamber opening Ri greens and, and the volume chamber is formed narrower than the reservoir chamber Than is.

Therefore, in the present invention, since the inflow pipe is connected to the bottom portion, the bottom portion is placed at a position higher than the head portion, and therefore the oil level is at the end surface of the bottom portion, that is, the inflow pipe. even become opposite situation to the end surface to be projected, and it is possible not to lead to a situation of mixing air into the hydraulic oil air intrudes into the bottom portion.

  Further, in the present invention, since the outflow pipe connected to the head portion is formed in the bottom portion and is defined as the reservoir chamber, it opens to the chamber that communicates with the inner cylinder. The hydraulic oil from the head portion communicating with the inside is not discharged into the reservoir chamber but is discharged into the bottom chamber.

At this time, the vessel chamber at the bottom part, since it is narrower in comparison to the reservoir chamber, also viewed in principle, the expression of aeration phenomenon to incorporate air into the hydraulic oil flows out into the vessel chamber No more feared.

  When the hydraulic oil flows into the chamber through the outflow pipe, for example, even if the bottom portion side of the hydraulic shock absorber is 0.2 m / sec or more, that is, it is vibrated at high speed, The so-called turbulence of the hydraulic oil can be avoided, so that a situation in which air is mixed into the hydraulic oil in the chamber is not caused.

  In the following, the present invention will be described based on the illustrated embodiment. However, the illustrated hydraulic shock absorber is used in a so-called horizontal position, such as a rolling prevention damper in a railway vehicle or a vibration damper in a building. It is supposed to.

  The hydraulic shock absorber shown in the figure is a uniflow type, that is, a one-way flow type, and is set so as to have the same damping characteristic during a so-called expansion / contraction operation. However, it is a matter of course that even a hydraulic shock absorber set other than the uniflow type does not hinder the realization of the present invention.

  By the way, the hydraulic shock absorber shown in FIG. 1 is formed in a double cylinder type having a reservoir chamber R having a cylindrical shape between an inner cylinder 1 and an outer cylinder 2 arranged concentrically with the inner cylinder 1. It is supposed to be done.

  The reservoir chamber R has an oil level O in the upper part, which is the upper side in the figure, because the hydraulic shock absorber is used in a horizontal position. The gas chamber G is used as a boundary.

  At this time, in the gas chamber G, the oxidation of the hydraulic oil is prevented. For example, even when the nitrogen gas is under a low pressure close to the atmospheric pressure or when the gas chamber G is expanded most, a constant gas pressure is exhibited. It is said to be sealed under high pressure that can be expected.

  Next, the hydraulic shock absorber is slidably accommodated in the inner cylinder 1 and is held at the distal end portion of the rod body 3 while defining the rod side chamber R1 and the piston side chamber R2 in the inner cylinder 1. The piston body 4 is provided.

  In this hydraulic shock absorber, the piston body 4 has a check valve 4a that allows the hydraulic oil from the piston side chamber R2 to flow into the rod side chamber R1 but prevents the reverse flow. .

  At this time, when the hydraulic oil from the piston side chamber R2 on the high pressure side flows into the rod side chamber R1 on the low pressure side, the check valve 4a positively attenuates depending on the specific configuration. That is, it may function as a damping valve.

  Therefore, in this hydraulic shock absorber, the check valve 4a of the piston body 4 can be said to be replaced with a damping valve, although not shown, considering that this functions as a damping valve. It will be.

  Further, in this hydraulic shock absorber, one end of the inner cylinder 1 and the outer cylinder 2 which are the left ends in the drawing, that is, the rod body 3 is allowed to penetrate into the shaft core portion while closing one end opening. It has a head portion 5, and has a bottom portion 6 that closes the other ends of the inner cylinder 1 and the outer cylinder 2 that are the right ends in the drawing, that is, the other end opening.

  In this hydraulic shock absorber, the head portion 5 has a check valve 5a that allows the hydraulic oil to flow out of the rod side chamber R1 into the reservoir chamber R but prevents the reverse flow. The check valve 5a also functions as a damping valve.

  Further, in this hydraulic shock absorber, the bottom portion 6 has a check valve 6a that allows the hydraulic oil from the reservoir chamber R to flow into the piston-side chamber R2, but prevents the reverse flow. .

  Although the above-described check valves 4a, 5a, and 6a are configured, any configuration can be selected as long as a predetermined check function is exhibited and hydraulic fluid is allowed to pass. A configuration with a steel ball or leaf valve biased by a spring would be common.

  On the other hand, in this hydraulic shock absorber, an outflow pipe that protrudes from the head portion 5 and allows passage of hydraulic oil from the inside of the inner cylinder 1, that is, from the rod side chamber R1 toward the reservoir chamber R side. 7 and has an inflow pipe 8 that protrudes from the bottom portion 6 and allows the hydraulic oil from the reservoir chamber R to pass into the inner cylinder 1, that is, to the piston side chamber R2.

  At this time, in the hydraulic shock absorber, the outflow pipe 7 is formed in a state in which the tip which is the right end in the figure is completely defined in the bottom portion 6 as the reservoir chamber R, while being formed in the inner cylinder 1, That is, it opens to the container chamber 6b communicating with the piston-side chamber R2, and this container chamber 6b is formed by opening the base end of the inflow pipe 8 as well.

  From the point of view of the present invention, it can be said that the outflow pipe 7 and the inflow pipe 8 are only required to be disposed in the hydraulic oil in the reservoir chamber R. Therefore, the outflow pipe 7 and the inflow pipe 8 are not arranged apart from each other in order not to make the chamber 6b unnecessarily large. In many cases, it will be placed in a neighboring state, as shown.

  By the way, the outflow pipe 7 and the inflow pipe 8 are formed of a pipe body so as to allow the passage of hydraulic oil inside, and the base end portion of the outflow pipe 7 is connected to the head portion, and the distal end portion of the outflow pipe 7 And the base end portion of the inflow pipe 8 are connected to the bottom portion 6 respectively.

  At this time, as for the connection structure of the outflow pipe 7 and the inflow pipe 8 to the head part 5 or the bottom part 6, other arbitrary connection structures may be selected in place of the press-fitting structure as shown in the figure. In order to prevent the head portion 5 and the bottom portion 6 from falling off easily during vibration to the container, that is, to the outer cylinder 2, for example, it is preferable to be screwed.

  Incidentally, the inside of the outflow pipe 7 not only communicates with the chamber 6b of the bottom section 6, but also communicates with the downstream side of the check valve 5a provided in the head section 5, and the inflow pipe 8 The inner side communicates with the reservoir chamber R and communicates with the chamber 6b of the bottom portion 6 and the upstream side of the check valve 6a.

  Further, in the hydraulic shock absorber, since the axial force acting on the hydraulic shock absorber does not act on the outflow pipe 7 and the inflow pipe 8 described above, each pipe forming the outflow pipe 7 and the inflow pipe 8 It can be said that the body may be formed thin and light.

  And since each pipe body which is this outflow pipe 7 and inflow pipe 8 is formed thin and light, it becomes possible not to unnecessarily increase the weight in the hydraulic shock absorber, but this outflow pipe 7 and inflow pipe 8 are made thin. For example, a metal material or a synthetic resin material that does not cause the hydraulic oil to be modified is preferably selected.

  Further, since the outflow pipe 7 and the inflow pipe 8 are formed to be thin and light, for example, even when both ends are fixed at the time of vibration to the bottom portion 6, compared with the inflow pipe 8. In the case where there is a concern that vibration is generated in the long outflow pipe 7, as shown in FIGS. 2 and 3, the vibration suppressing member 9 for suppressing the vibration of the outflow pipe 7 is, for example, a synthetic resin material or It would be preferable to be interposed on the outer periphery of the intermediate portion of the outflow pipe 7 while being formed of a rubber material or the like.

  At this time, the vibration suppressing member 9 is arranged not only on the outer periphery of the intermediate portion of the outflow pipe 7 but also so as to be connected to the adjacent inflow pipe 8 as shown by a virtual diagram in FIG. If it is arranged, it will be preferable from the viewpoint of improving the fixing property of the vibration suppressing member 9.

  Since the vibration suppressing member 9 is partially disposed in the reservoir chamber R, it does not obstruct the flow of hydraulic oil in the reservoir chamber R. By forming it, it can be said that it also functions in the direction of suppressing the movement of hydraulic oil in the reservoir chamber R.

  From this, it is expected that the reservoir chamber R having the vibration suppressing member 9 particularly in the hydraulic oil functions to suppress movement when the hydraulic oil in the reservoir chamber R is vibrated. It can be said that it functions in the direction of suppressing the disturbance of the oil level O.

  The vibration suppressing member 9 is arranged so as to be sandwiched between the inner cylinder 1 and the outer cylinder 2 and fixed at a so-called predetermined position as shown in FIG. In addition, when the vibration suppression member 9 is maintained in contact with the inner cylinder 1 and the outer cylinder 2, the natural frequency in the inner cylinder 1 and the outer cylinder 2 can be changed. It will also be possible to avoid resonance during excitation in the hydraulic shock absorber by selecting the material forming the material, selecting the mass, or the like.

  Therefore, in the hydraulic shock absorber according to the present invention formed as described above, for example, when the piston body 4 extends in the left direction in the inner cylinder 1 in FIG. Since R1 is on the high pressure side, the hydraulic oil in the rod side chamber R1 flows out into the outflow pipe 7 whose base end is connected to the head portion 5 via the check valve 5a provided in the head portion 5. Become.

The hydraulic oil that has flowed into the outflow pipe 7 flows into the chamber 6b formed in the bottom portion 6, and the inner cylinder 1 through the check valve 6a disposed in the bottom portion 6 from the chamber 6b. It flows into the inner piston side chamber R2.

  At this time, hydraulic fluid from the head portion 5 communicating with the inner cylinder 1 flows into the chamber 6 b of the bottom portion 6 through the outflow pipe 7 connected to the head portion 5 and does not flow out into the reservoir chamber R. Therefore, it is possible to prevent the occurrence of the aeration phenomenon that occurs when the hydraulic oil flows out into the reservoir chamber R, that is, the phenomenon that air is mixed into the hydraulic oil.

At this time, the vessel chamber 6b of the bottom section 6, since it is narrower in comparison to the reservoir chamber R, also in this vessel chamber 6b, the expression of aeration phenomenon of mixing air is feared in the hydraulic fluid Disappear.

  Not only that, when hydraulic fluid flows into the chamber 6b through the outflow pipe 7, for example, the hydraulic shock absorber, that is, the bottom portion 6 of the hydraulic shock absorber becomes 0.2 m / sec or higher, so to speak. Even if a situation occurs in which the chamber 6b is vibrated, the so-called turbulence of the hydraulic fluid in the chamber 6b can be avoided because the chamber 6b is narrow, and therefore, a situation occurs in which air is mixed into the hydraulic fluid in the chamber 6b. It is possible not to let it.

  Incidentally, at the time of this extension operation, in the piston side chamber R 2 in the inner cylinder 1, if the hydraulic oil from the rod side chamber R 1 flows into the piston side chamber R 2, it becomes negative pressure, so the hydraulic oil from the reservoir chamber R passes through the inflow pipe 8. Then, it flows into the chamber 6b of the bottom portion 6 and then flows into the piston side chamber R2 in the inner cylinder 1 to prevent the vacuum phenomenon from occurring in the piston side chamber R2.

  In contrast, when the piston body 4 in FIG. 1 is contracted to move rightward in the inner cylinder 1, a check valve 6 a is provided at the bottom portion 6, and the hydraulic oil in the piston side chamber R <b> 2 in the inner cylinder 1 is provided. Is prevented from flowing out into the reservoir chamber R, so that the piston side chamber R2 becomes the high pressure side, and the hydraulic oil from the piston side chamber R2 is said to have a low pressure side through the check valve 4a provided in the piston body 4. It will flow into the rod side chamber R1 in the inner cylinder 1 to be.

  At this time, even the amount of hydraulic oil corresponding to the so-called surplus rod volume integral, which is surplus in the piston side chamber R2, flows into the rod side chamber R1, and therefore, this surplus is accommodated in the rod side chamber R1. Therefore, the rod-side chamber R1 becomes the high-pressure side as long as this limit is reached, and this surplus portion flows out into the outflow pipe 7 via the check valve 5a provided in the head portion 5.

  Then, the hydraulic oil that has flowed into the outflow pipe 7 flows into the piston side chamber R2 through the same route as described above. At this time, the surplus amount of hydraulic oil in the rod side chamber R1 becomes the bottom portion 6. From the container chamber 6b to the reservoir chamber R through the inflow pipe 8.

  In the hydraulic shock absorber according to the present invention, since the bottom portion 6 has the inflow pipe 8, for example, the bottom portion 6 is placed at a position higher than the head portion 5. Even if it faces the end surface of the bottom portion 6, that is, the end surface on which the inflow pipe 8 is protruded, air will not enter the bottom portion 6 and cause air to be mixed into the hydraulic oil. Become.

  Therefore, in the hydraulic shock absorber according to the present invention, it is not necessary to worry about the occurrence of the aeration phenomenon in the reservoir chamber R, and the occurrence of the aeration phenomenon in the chamber 6b of the bottom portion 6 is prevented. Therefore, it is possible to prevent inconveniences such as adiabatic compression and malfunction of the valve due to air mixture in the hydraulic oil.

  As described above, according to the present invention, the tip of the outflow pipe 7 and the inflow flow into the chamber 6 b that is formed in the bottom portion 6 so as to be completely defined as the reservoir chamber R and communicates with the inner cylinder 1. Assuming that the proximal end of the tube 8 is open, it is possible to prevent the aeration phenomenon from occurring in the chamber 6b. From this, the chamber 6b is replaced with the above-described one. 1 and 2, the bottom portion 6 is formed in a passage (not shown) that connects the check valve 6a and the chamber 6b shown in the solid line diagram. Also good and get good.

It is a figure which shows in principle the hydraulic shock absorber by one Embodiment of this invention. It is a figure which shows the positional relationship of the outflow pipe | tube seen from the XX line position in FIG. 1, and an inflow pipe | tube. It is a figure which shows the positional relationship of the outflow pipe | tube seen from the YY line position in FIG. 2, and an inflow pipe | tube.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner cylinder 2 Outer cylinder 3 Rod body 4 Piston body 4a, 5a, 6a Check valve 5 Head part 6 Bottom part 6b Chamber 7 Outflow pipe 8 Inflow pipe R Reservoir room R1 Rod side room R2 Piston side room

Claims (7)

It has a reservoir chamber between the inner cylinder and an outer cylinder, has a head portion for closing one end opening of the end openings and the outer tube of the inner tube, the other of the other end opening and the outer tube of the inner tube It has a bottom portion which closes the end opening, so as to project the head portion has a outflow pipe which permits the passage of toward the reservoir chamber side of the hydraulic oil from within the inner cylinder, to the bottom portion in the hydraulic shock absorber is projected comprising a inlet tube permitting passage into the inner cylinder of the hydraulic oil from the reservoir chamber, the reservoir chamber tip of the outlet pipe is formed in the bottom portion and while being defined as to open to the volume chamber communicating with the said inner cylinder, Ri Na base end of the inflow pipe opens into the vessel chamber, that said vessel chamber is formed narrower than the reservoir chamber Features a hydraulic shock absorber. It has a rod member which is inserted into retractably through the axis portion in the inner cylindrical in the head portion, the rod-side chamber and a piston slidably housed has been in the inner cylindrical in the inner cylindrical while defining a side chamber has a piston body which is held to the tip portion of the rod member, but to permit entry into the rod side chamber of the hydraulic oil from the piston side chamber to the piston body blocks the flow in the reverse The hydraulic shock absorber according to claim 1, further comprising a check valve. It has a rod member which is inserted into retractably through the axis portion in the inner cylindrical in the head portion, the rod-side chamber and a piston slidably housed has been in the inner cylindrical in the inner cylindrical It has a piston body which is held to the tip portion of the rod member while defining a side chamber, a damping valve which permits reciprocation of the hydraulic fluid in between the piston side chamber and the rod side chamber to the piston member The hydraulic shock absorber according to claim 1. Claim to permit outflow of the hydraulic oil in the reservoir chamber from the rod side chamber in the head portion becomes a check valve or damping valve prevents flow in the reverse 1, claim 2 or claim 3 Hydraulic shock absorber as described in. Claim 1 comprising a check valve to allow inflow to the piston side chamber of the hydraulic oil from the reservoir chamber to the bottom portion but to prevent flow in the reverse, claim 2, claim 3 or claim 4. The hydraulic shock absorber according to 4 . With the vibration suppressing member to the intermediate portion of the outlet pipe is interposed, according to claim 1, the vibration suppressing member is formed by fixing between the inner tube and the outer tube, according to claim 2, claim 3, wherein The hydraulic shock absorber according to claim 4 or 5. With the vibration suppressing member to the intermediate portion of the outlet pipe is interposed, according to claim 1, the vibration suppressing member is formed by interposed in the inlet tube close to the outlet pipe, according to claim 2, claim 3, The hydraulic shock absorber according to claim 4 or 5.

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