WO2019054169A1 - Damper - Google Patents

Damper Download PDF

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Publication number
WO2019054169A1
WO2019054169A1 PCT/JP2018/031703 JP2018031703W WO2019054169A1 WO 2019054169 A1 WO2019054169 A1 WO 2019054169A1 JP 2018031703 W JP2018031703 W JP 2018031703W WO 2019054169 A1 WO2019054169 A1 WO 2019054169A1
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WO
WIPO (PCT)
Prior art keywords
shock absorber
helium
cylinder
air chamber
chamber
Prior art date
Application number
PCT/JP2018/031703
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French (fr)
Japanese (ja)
Inventor
栗田 典彦
Original Assignee
Kyb株式会社
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Publication date
Application filed by Kyb株式会社 filed Critical Kyb株式会社
Publication of WO2019054169A1 publication Critical patent/WO2019054169A1/en

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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60GVEHICLE SUSPENSION ARRANGEMENTS
    • B60G13/00Resilient suspensions characterised by arrangement, location or type of vibration dampers
    • B60G13/02Resilient suspensions characterised by arrangement, location or type of vibration dampers having dampers dissipating energy, e.g. frictionally
    • B60G13/06Resilient suspensions characterised by arrangement, location or type of vibration dampers having dampers dissipating energy, e.g. frictionally of fluid type
    • B60G13/08Resilient suspensions characterised by arrangement, location or type of vibration dampers having dampers dissipating energy, e.g. frictionally of fluid type hydraulic
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60GVEHICLE SUSPENSION ARRANGEMENTS
    • B60G15/00Resilient suspensions characterised by arrangement, location or type of combined spring and vibration damper, e.g. telescopic type
    • B60G15/08Resilient suspensions characterised by arrangement, location or type of combined spring and vibration damper, e.g. telescopic type having fluid spring
    • B60G15/12Resilient suspensions characterised by arrangement, location or type of combined spring and vibration damper, e.g. telescopic type having fluid spring and fluid damper
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16FSPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/06Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium using both gas and liquid
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16FSPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/06Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium using both gas and liquid
    • F16F9/08Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium using both gas and liquid where gas is in a chamber with a flexible wall
    • F16F9/084Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium using both gas and liquid where gas is in a chamber with a flexible wall comprising a gas spring contained within a flexible wall, the wall not being in contact with the damping fluid, i.e. mounted externally on the damper cylinder

Definitions

  • the present invention relates to improvements in shock absorbers.
  • a shock absorber as disclosed in, for example, JP2011-174502, a liquid and a gas are enclosed inside, and the flow of the liquid generated at the time of expansion and contraction is provided to exert a damping force.
  • shock absorbers it is most common to use air as the gas filled with the liquid inside, and sometimes nitrogen is also used.
  • the present invention is devised to improve the above-mentioned problems, and an object of the present invention is to provide a shock absorber capable of suppressing the occurrence of cavitation and making a damping force generation response excellent.
  • the means for solving the above problems is to form a helium filled air chamber in a shock absorber that exerts a damping force by resisting the flow of the liquid generated during expansion and contraction.
  • Helium has a low molecular weight and low solubility in the liquid, and according to this configuration, the occurrence of cavitation can be suppressed and the generation response of the damping force can be improved because the dissolved gas in the liquid is reduced.
  • FIG. 1 is a longitudinal sectional view schematically showing a shock absorber according to one embodiment of the present invention.
  • FIG. 2 is a diagram showing the relationship between gas solubility in water and temperature.
  • FIG. 3 is a longitudinal sectional view showing a first modified example of the shock absorber according to one embodiment of the present invention and simplifying the shock absorber according to the modified example.
  • FIG. 4 is a longitudinal sectional view showing a second modified example of the shock absorber according to one embodiment of the present invention and simplifying the shock absorber according to the modified example.
  • FIG. 5 is a longitudinal sectional view showing a third modified example of the shock absorber according to one embodiment of the present invention and simplifying the shock absorber according to the modified example.
  • a shock absorber D As shown in FIG. 1, a shock absorber D according to an embodiment of the present invention is used for a front fork, and is interposed between a vehicle body of a straddle-type vehicle and an axle of a front wheel.
  • the shock absorber D includes a telescopic tube member 1 and a single rod shock absorber body 2 housed in the tube member 1.
  • the tube member 1 is configured to have an outer tube 3 and an inner tube 4 slidably inserted into the outer tube 3 via a pair of bushes 30 and 40.
  • the tube member 1 is an inverted type, and the outer tube 3 is disposed on the upper side (vehicle body side) and the inner tube 4 is disposed on the lower side (axle side). That is, in the present embodiment, the outer tube 3 is a vehicle body side tube, and the inner tube 4 is an axle side tube.
  • the outer tube 3 is connected to the vehicle body of the saddle-ride type vehicle via the vehicle body side bracket (not shown), and the inner tube 4 is connected to the axle of the front wheel of the saddle-ride type vehicle via the axle side bracket 10 There is.
  • the shock absorber D is interposed between the vehicle body and the axle, and when the front wheel vibrates up and down due to the straddle type vehicle traveling on the uneven road surface, the inner tube 4 becomes the outer tube.
  • the shock absorber D expands and contracts in and out of 3.
  • the tube member 1 may be an upright type, and the outer tube 3 may be an axle tube and the inner tube 4 may be a vehicle tube. Further, the application of the shock absorber D is not limited to the front fork, and may be used for a rear cushion unit that suspends the rear wheel of a straddle-type vehicle, a suspension of an automobile, or the like.
  • the upper side of the outer tube 3 in FIG. 1 is closed with a cap 11. Further, the lower side in FIG. 1 of the inner tube 4 is closed by the axle side bracket 10. Furthermore, the sealing member 12 is closed between the overlapping portion of the outer tube 3 and the inner tube 4. Thus, the tube member 1 is sealed, and the shock absorber main body 2 is accommodated inside thereof.
  • the shock absorber main body 2 includes a cylinder 5, a piston 6 axially slidably inserted in the cylinder 5, and a piston rod 60 having one end connected to the piston 6 and the other end protruding out of the cylinder 5; It has an annular rod guide 50 fixed to one end of the cylinder 5 and slidably supporting the piston rod 60, and a valve case 7 fixed to the lower end of the cylinder 5.
  • the shock absorber main body 2 is an upright type, and the piston rod 60 is disposed on the upper side (vehicle body side) and the cylinder 5 is directed to the lower side (axle side).
  • the piston rod 60 is connected to the outer tube 3 via the cap 11, and the cylinder 5 is connected to the inner tube 4 via the axle side bracket 10.
  • the shock absorber main body 2 is interposed between the outer tube 3 and the inner tube 4, and when the shock absorber D expands and contracts, the piston rod 60 moves in and out of the cylinder 5 and the shock absorber main body 2 expands and contracts.
  • the piston 6 moves up and down in the cylinder 5.
  • the upper side of the cylinder 5 in FIG. 1 is closed by a rod guide 50.
  • the lower side of the cylinder 5 is closed by a valve case 7.
  • the inside of the cylinder 5 is divided by the piston 6 into an expansion side chamber L 1 and a pressure side chamber L 2.
  • the hydraulic oil is filled in the expansion side chamber L1 and the pressure side chamber L2, respectively.
  • the piston 6 is formed with a damping passage 6a that communicates the expansion side chamber L1 with the pressure side chamber L2.
  • the damping passage 6a is provided with a damping element 6b that resists the flow of hydraulic fluid moving between the expansion side chamber L1 and the pressure side chamber L2 through the damping path 6a.
  • a reservoir R is formed outside the cylinder 5 with the tube member 1.
  • the reservoir R stores hydraulic oil and is filled with a gas above the liquid surface.
  • a portion where hydraulic oil is stored is referred to as a liquid reservoir L3
  • a portion filled with a gas is referred to as an air chamber G.
  • a suction passage 7a and a discharge passage 7b are formed, which communicate the pressure side chamber L2 and the liquid storage chamber L3.
  • the suction passage 7a is provided with a check valve 7c that allows the flow of hydraulic oil from the liquid storage chamber L3 to the pressure side chamber L2 and blocks the flow in the opposite direction.
  • the discharge passage 7b is provided with a damping element 7d that resists the flow of hydraulic fluid moving between the pressure side chamber L2 and the liquid storage chamber L3 through the discharge passage 7b.
  • the piston rod 60 withdraws from the cylinder 5 and the shock absorber main body 2 extends, and the piston 6 moves upward in the cylinder 5 in FIG. 1 to compress the expansion chamber L1. Then, the hydraulic oil in the expansion side chamber L1 moves to the pressure side chamber L2 through the damping passage 6a. Since the damping element 6b applies resistance to the flow of the hydraulic fluid, the pressure of the expansion chamber L1 increases when the shock absorber D is extended, and the shock absorber body 2 exerts a damping force that suppresses the extension operation. Do.
  • the hydraulic fluid flows in the cylinder 5 or between the cylinder 5 and the reservoir R along with the extension operation, and the flow of the hydraulic fluid is damped by giving resistance to the flow of the hydraulic fluid by the damping elements 6b and 7d.
  • Force is supposed to be generated.
  • the structure of damping element 6b, 7d can also be changed suitably.
  • an orifice, a choke, a valve or the like can be used as the damping elements 6b and 7d.
  • the check valve 7c is opened, and the hydraulic oil for the piston rod volume which has been withdrawn from the cylinder 5 is supplied from the reservoir R to the pressure side chamber L2 through the suction passage 7a.
  • the working oil of the piston rod volume entering the cylinder 5 is discharged from the pressure side chamber L2 to the reservoir R through the discharge passage 7b.
  • the reservoir R compensates for the volume of the piston rod 60 that moves into and out of the cylinder 5 as the expansion and contraction operation is performed.
  • the gas filled in the air chamber G of the reservoir R is helium.
  • a gas spring A is formed with the air chamber G, and the gas spring A functions as a suspension spring for urging the shock absorber D in the extension direction to elastically support the vehicle body.
  • FIG. 2 is a diagram showing the relationship between the solubility of oxygen (O 2 ), nitrogen (N 2 ) and helium (He) in water and the temperature.
  • O 2 oxygen
  • N 2 nitrogen
  • He helium
  • the solubility of helium is small and the change in solubility with temperature is small compared to oxygen and nitrogen.
  • the solubilities of nitrogen and oxygen decrease with increasing temperature, but the solubilities of helium increase slightly at higher temperatures.
  • the solubility of gas in oil is greater than the solubility of gas in water, it is known that the temperature dependence of solubility by gas type has a similar tendency.
  • helium is less soluble in hydraulic oil than oxygen and nitrogen, and the change in solubility due to temperature change is also small. Also, the solubility of oxygen and nitrogen in hydraulic fluid decreases with increasing temperature, while the solubility of helium in hydraulic fluid increases slightly with increasing temperature.
  • air is most commonly used as a gas with which the shock absorber is filled with the hydraulic oil, and nitrogen may also be used.
  • the composition of air is about 80% nitrogen and about 20% oxygen.
  • helium is less soluble in hydraulic oil compared to oxygen and nitrogen. Therefore, in the case of the shock absorber D filled with helium as in the present embodiment, the dissolved gas in the hydraulic oil is reduced as compared with the conventional shock absorber filled with air or nitrogen.
  • the shock absorber D of the present embodiment the occurrence of cavitation can be suppressed and the occurrence response of the damping force can be made better as compared with the conventional shock absorber. Further, helium is relatively inexpensive and easily available, and therefore, according to the above configuration, the occurrence of cavitation can be suppressed and the improvement of damping force generation responsiveness can be realized inexpensively and easily.
  • the shock absorber D according to the present embodiment filled with helium starts traveling Even if the temperature of the shock absorber D rises, the rise in internal pressure can be suppressed. Therefore, in the shock absorber D, it is possible to suppress the change in the elastic force of the gas spring A when the vehicle is traveling, and to suppress the change in the ride comfort of the vehicle.
  • the gas spring A functions as a suspension spring that elastically supports the vehicle body as in the shock absorber D of the present embodiment, compared to a shock absorber having a suspension spring consisting of a coil spring, The change in the elastic force has a large effect on the ride quality of the vehicle.
  • motocrosser since a traveling vehicle called motocrosser travels on an unpaved circuit course, a strong vibration is added to the shock absorber when the vehicle is traveling. For this reason, when a shock absorber using a conventional air spring or a gas spring configured to have an air chamber filled with nitrogen as a suspension spring is used as a motocross, the ride quality of the vehicle is degraded several laps after the start of traveling . In this case, it is necessary to return to the pit and adjust the pressure of the air chamber again, and it takes time and effort because it can not cope during traveling.
  • the shock absorber D having the gas spring A configured to have the air chamber G filled with helium as a suspension spring as described above, the change in the elastic force of the gas spring A can be suppressed. , Can maintain a good ride. That is, in the case where the gas spring A functions as a suspension spring that elastically supports the vehicle body, it is particularly effective to fill with helium when the shock absorber D is used for motocross.
  • the pressure in the air chamber G may rise to about 15 atm (atm), depending on the setting.
  • the hydraulic oil and oxygen may combine to generate carbon dioxide. Since the solubility of carbon dioxide is higher than the solubility of oxygen, there is a risk that dissolved gas may be further increased. Therefore, if the buffer D is filled with helium as in the present embodiment, such a problem does not occur.
  • shock absorber D filled with helium, if the air in the working oil is replaced with helium in advance by the helium purge and then the shock absorber D is filled, the dissolved gas in the working oil can be further reduced. For this reason, it is advantageous in suppressing the occurrence of cavitation and improving the damping force response.
  • helium has the property of permeating rubber. Furthermore, helium molecules are so small that they can also penetrate metals in some cases.
  • an oil film is formed by the seal member 12 on the outer peripheral surface of the inner tube 4 which is withdrawn from the outer tube 3 when the shock absorber D is extended. Therefore, helium in the oil film exposed to the outside air is released to the atmosphere, and nitrogen, oxygen and the like in the atmosphere are dissolved in the oil film. Then, the oil film returns into the outer tube 3 when the shock absorber D contracts. Under these circumstances, even if the shock absorber D is filled with helium, helium leaks with the passage of time and operation, and helium and air are replaced.
  • the pressure in the air chamber G is set higher compared to a shock absorber provided with a suspension spring consisting of a coil spring. Since the amount of gas that is soluble in a certain amount of solvent is proportional to the pressure, a large amount of helium dissolves in the working oil in the high-pressure buffer D. Then, when the hydraulic oil containing a large amount of helium is carried out of the shock absorber D as an oil film at the time of extension of the shock absorber D, helium which can not be dissolved due to the pressure drop is released to the atmosphere.
  • shock absorber D filled with helium
  • the gas spring A configured to have a gas chamber G filled with helium
  • the helium is periodically replenished. While it is necessary to use. Therefore, such a shock absorber is suitable for use in a competition vehicle whose maintenance is frequently performed, or a vehicle provided with a spring force adjustment device or the like that automatically adjusts the pressure in the air chamber. This is because in these vehicles, helium can be supplied to the air chamber G at the time of maintenance or adjustment of the air chamber pressure.
  • the shock absorber D itself may be provided with a replenishment device for replenishing helium to the air chamber G.
  • the filling device may have any configuration, for example, a tank filled with helium, a passage connecting the tank and the air chamber G, and a pressure from the tank to the air chamber according to the pressure in the air chamber G It may be configured to have a valve or the like for supplying helium to G.
  • the shock absorber D is connected to the cylinder 5, the piston 6 slidably inserted in the cylinder 5, and one end is connected to the piston 6 and the other end protrudes out of the cylinder 5
  • the gas is in contact with the oil surface of the hydraulic fluid in the reservoir R, it is particularly effective to use helium as the gas, provided with the piston rod 60 and the reservoir R communicated in the cylinder 5.
  • the dissolved air in the hydraulic oil can be replaced with helium in the reservoir R, and the hydraulic oil moves between the reservoir R and the cylinder 5 when the shock absorber D expands and contracts. If helium is contained, the dissolved gas in the hydraulic oil in the cylinder 5 can be reduced, and the effect of preventing the occurrence of cavitation and improving the response of generation of damping force can be obtained.
  • a suspension spring consisting of a coil spring may be provided between the rod guide 50 and the cap 11, and the pressure of the air chamber G at the time of the maximum extension may be approximately atmospheric pressure.
  • the reservoir R is formed between the outer cylinder 51 provided on the outer periphery of the cylinder 5 and the cylinder 5, and A chamber 8 forming a second air chamber G1 may be provided, and a gas spring A1 having a second air chamber G1 and functioning as a suspension spring may be configured.
  • the air chamber G in the reservoir R is filled with helium, the air in the hydraulic oil can be replaced with helium in the reservoir R. Therefore, the gas filling the air chamber G1 in the chamber 8 may be other than helium, and the chamber 8 may be eliminated and a suspension spring made of a coil spring may be provided.
  • the liquid storage chamber L3 of the reservoir R and the air chamber G may be partitioned by the free piston 52.
  • the piston rod is removed from the reservoir R and enters and exits the cylinder 5 in the expandable air chamber G2 partitioned by the free piston 53 in the cylinder 5. 60 volume compensation may be performed.
  • helium is easy to permeate. For this reason, even if the air chamber filled with helium and the oil chamber filled with the working oil are partitioned by a movable piston such as a free piston, a bladder or a bellows, the helium in the air chamber can move to the oil chamber side. That is, even in the case where the air chamber partitioned from the oil chamber by the movable partition is filled with helium, the air in the working oil can be gradually replaced with helium, and the dissolved gas in the working oil can be reduced.
  • a movable piston such as a free piston, a bladder or a bellows
  • the communication hole 5a provided in the cylinder 5 of the shock absorber D2 according to the second modification shown in FIG. 4 is eliminated to divide the air chamber G into the inside and outside of the cylinder 5, and to the air chamber Ga in the cylinder 5.
  • Helium may be filled, and the air chamber Gb outside the cylinder 5 may be filled with a gas other than helium.
  • helium is filled in the air chamber G2 of the shock absorber D3 according to the third modification shown in FIG. 5, and the chamber 8 is filled with a gas other than helium, or the chamber 8 is discarded, and the gas spring A1 is replaced A suspension spring consisting of a coil spring may be provided.
  • the piston rod 60 extends to one side of the piston 6 and is of a single rod type.
  • the piston rod 60 may be extended to both sides of the piston 6 to be a double rod type.
  • hydraulic oil is used as a liquid for generating damping force
  • water may be used, and the temperature dependence characteristics of the solubility of oxygen, nitrogen and helium are similar to FIG. As long as the liquid is a characteristic, a liquid other than hydraulic oil and water may be used.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Fluid-Damping Devices (AREA)
  • Vehicle Body Suspensions (AREA)

Abstract

In a damper which provides damping force by applying resistance to the flow of liquid occurring during the extension and contraction of the damper, when the amount of gas dissolved in the liquid is large, the gas dissolved in the liquid forms bubbles to cause a phenomenon known as cavitation, delaying the build-up of damping force at the time of the start of extension and contraction of the damper. A damper (D) provided as a means for solving such a problem has a gas chamber G formed in the damper (D) and filled with helium, the damper (D) providing damping force by applying resistance to the flow of liquid occurring during the extension and contraction of the damper (D).

Description

緩衝器Shock absorber
 本発明は、緩衝器の改良に関する。 The present invention relates to improvements in shock absorbers.
 従来、緩衝器の中には、たとえば、JP2011-174502に開示されているように、内部に液体と気体が封入されていて、伸縮時に生じる液体の流れに抵抗を与えて減衰力を発揮するものがある。このような緩衝器では、内部に液体とともに充填する気体として、エア(空気)を利用するのが最も一般的であり、窒素を利用することもある。 Conventionally, in a shock absorber, as disclosed in, for example, JP2011-174502, a liquid and a gas are enclosed inside, and the flow of the liquid generated at the time of expansion and contraction is provided to exert a damping force. There is. In such shock absorbers, it is most common to use air as the gas filled with the liquid inside, and sometimes nitrogen is also used.
 緩衝器において、液体中に溶け込んだ気体が多いと、液中に溶けていた気体が気泡となって生じるキャビテーションと称される現象が発生し、緩衝器の伸縮し始めにおいて減衰力の立ち上がりが遅れたりする問題がある。 In a shock absorber, if there is a large amount of dissolved gas in the liquid, a phenomenon called cavitation occurs in which the dissolved gas in the liquid forms bubbles, and the rise of damping force is delayed at the beginning of expansion and contraction of the shock absorber. Have problems
 そこで、本発明は、上記した不具合を改善するために創案されたものであり、キャビテーションの発生を抑制し、減衰力発生応答性を良好にできる緩衝器の提供を目的とする。 Therefore, the present invention is devised to improve the above-mentioned problems, and an object of the present invention is to provide a shock absorber capable of suppressing the occurrence of cavitation and making a damping force generation response excellent.
 上記課題を解決する手段は、伸縮時に生じる前記液体の流れに抵抗を与えて減衰力を発揮する緩衝器内にヘリウムを充填した気室を形成することである。ヘリウムは、分子量が小さくて液体への溶解度が低く、当該構成によれば、液体中の溶存気体が減少するので、キャビテーションの発生を抑制し、減衰力の発生応答性を良好にできる。 The means for solving the above problems is to form a helium filled air chamber in a shock absorber that exerts a damping force by resisting the flow of the liquid generated during expansion and contraction. Helium has a low molecular weight and low solubility in the liquid, and according to this configuration, the occurrence of cavitation can be suppressed and the generation response of the damping force can be improved because the dissolved gas in the liquid is reduced.
図1は、本発明の一実施の形態に係る緩衝器を簡略化して示した縦断面図である。FIG. 1 is a longitudinal sectional view schematically showing a shock absorber according to one embodiment of the present invention. 図2は、気体の水に対する溶解度と温度との関係を示した図であるFIG. 2 is a diagram showing the relationship between gas solubility in water and temperature. 図3は、本発明の一実施の形態に係る緩衝器の第一の変形例を示し、当該変形例に係る緩衝器を簡略化して示した縦断面図である。FIG. 3 is a longitudinal sectional view showing a first modified example of the shock absorber according to one embodiment of the present invention and simplifying the shock absorber according to the modified example. 図4は、本発明の一実施の形態に係る緩衝器の第二の変形例を示し、当該変形例に係る緩衝器を簡略化して示した縦断面図である。FIG. 4 is a longitudinal sectional view showing a second modified example of the shock absorber according to one embodiment of the present invention and simplifying the shock absorber according to the modified example. 図5は、本発明の一実施の形態に係る緩衝器の第三の変形例を示し、当該変形例に係る緩衝器を簡略化して示した縦断面図である。FIG. 5 is a longitudinal sectional view showing a third modified example of the shock absorber according to one embodiment of the present invention and simplifying the shock absorber according to the modified example.
 以下に本発明の実施の形態の緩衝器について、図面を参照しながら説明する。いくつかの図面を通して付された同じ符号は、同じ部品か対応する部品を示す。 Hereinafter, a shock absorber according to an embodiment of the present invention will be described with reference to the drawings. The same reference numerals as in the several figures indicate the same or corresponding parts.
 図1に示すように、本発明の一実施の形態に係る緩衝器Dは、フロントフォークに利用されており、鞍乗型車両の車体と前輪の車軸との間に介装されている。緩衝器Dは、テレスコピック型のチューブ部材1と、チューブ部材1内に収容される片ロッド型の緩衝器本体2とを備える。 As shown in FIG. 1, a shock absorber D according to an embodiment of the present invention is used for a front fork, and is interposed between a vehicle body of a straddle-type vehicle and an axle of a front wheel. The shock absorber D includes a telescopic tube member 1 and a single rod shock absorber body 2 housed in the tube member 1.
 チューブ部材1は、アウターチューブ3と、一対のブッシュ30,40を介してアウターチューブ3内に摺動自在に挿入されるインナーチューブ4とを有して構成される。本実施の形態では、チューブ部材1が倒立型となっており、アウターチューブ3を上側(車体側)へ、インナーチューブ4を下側(車軸側)へ向けて配置される。つまり、本実施の形態では、アウターチューブ3が車体側チューブ、インナーチューブ4が車軸側チューブとなっている。 The tube member 1 is configured to have an outer tube 3 and an inner tube 4 slidably inserted into the outer tube 3 via a pair of bushes 30 and 40. In the present embodiment, the tube member 1 is an inverted type, and the outer tube 3 is disposed on the upper side (vehicle body side) and the inner tube 4 is disposed on the lower side (axle side). That is, in the present embodiment, the outer tube 3 is a vehicle body side tube, and the inner tube 4 is an axle side tube.
 そして、アウターチューブ3が車体側ブラケット(図示せず)を介して鞍乗型車両の車体に連結され、インナーチューブ4が車軸側ブラケット10を介して鞍乗型車両の前輪の車軸に連結されている。このように、緩衝器Dは、車体と車軸との間に介装されており、鞍乗型車両が凹凸のある路面を走行する等して前輪が上下に振動すると、インナーチューブ4がアウターチューブ3に出入りして緩衝器Dが伸縮する。 Then, the outer tube 3 is connected to the vehicle body of the saddle-ride type vehicle via the vehicle body side bracket (not shown), and the inner tube 4 is connected to the axle of the front wheel of the saddle-ride type vehicle via the axle side bracket 10 There is. As described above, the shock absorber D is interposed between the vehicle body and the axle, and when the front wheel vibrates up and down due to the straddle type vehicle traveling on the uneven road surface, the inner tube 4 becomes the outer tube. The shock absorber D expands and contracts in and out of 3.
 なお、チューブ部材1は、正立型になっていて、アウターチューブ3を車軸側チューブ、インナーチューブ4を車体側チューブとしてもよい。また、緩衝器Dの用途はフロントフォークに限られず、鞍乗型車両の後輪を懸架するリヤクッションユニット、又は自動車のサスペンション等に利用されてもよい。 The tube member 1 may be an upright type, and the outer tube 3 may be an axle tube and the inner tube 4 may be a vehicle tube. Further, the application of the shock absorber D is not limited to the front fork, and may be used for a rear cushion unit that suspends the rear wheel of a straddle-type vehicle, a suspension of an automobile, or the like.
 つづいて、アウターチューブ3の図1中上側は、キャップ11で塞がれている。また、インナーチューブ4の図1中下側は、車軸側ブラケット10で塞がれている。さらに、アウターチューブ3とインナーチューブ4の重複部の間は、シール部材12で塞がれている。このようにしてチューブ部材1は密閉されており、その内側に緩衝器本体2が収容されている。 Subsequently, the upper side of the outer tube 3 in FIG. 1 is closed with a cap 11. Further, the lower side in FIG. 1 of the inner tube 4 is closed by the axle side bracket 10. Furthermore, the sealing member 12 is closed between the overlapping portion of the outer tube 3 and the inner tube 4. Thus, the tube member 1 is sealed, and the shock absorber main body 2 is accommodated inside thereof.
 緩衝器本体2は、シリンダ5と、シリンダ5内に軸方向へ摺動自在に挿入されるピストン6と、一端がピストン6に連結されて他端がシリンダ5外へ突出するピストンロッド60と、シリンダ5の一端部に固定されてピストンロッド60を摺動自在に支持する環状のロッドガイド50と、シリンダ5の下端部に固定されるバルブケース7とを有する。 The shock absorber main body 2 includes a cylinder 5, a piston 6 axially slidably inserted in the cylinder 5, and a piston rod 60 having one end connected to the piston 6 and the other end protruding out of the cylinder 5; It has an annular rod guide 50 fixed to one end of the cylinder 5 and slidably supporting the piston rod 60, and a valve case 7 fixed to the lower end of the cylinder 5.
 また、緩衝器本体2は、正立型となっており、ピストンロッド60を上側(車体側)へ、シリンダ5を下側(車軸側)へ向けて配置されている。そして、ピストンロッド60がキャップ11を介してアウターチューブ3に連結されており、シリンダ5が車軸側ブラケット10を介してインナーチューブ4に連結されている。このように、緩衝器本体2は、アウターチューブ3とインナーチューブ4との間に介装されており、緩衝器Dが伸縮すると、ピストンロッド60がシリンダ5に出入りして緩衝器本体2が伸縮し、ピストン6がシリンダ5内を上下に移動する。 Further, the shock absorber main body 2 is an upright type, and the piston rod 60 is disposed on the upper side (vehicle body side) and the cylinder 5 is directed to the lower side (axle side). The piston rod 60 is connected to the outer tube 3 via the cap 11, and the cylinder 5 is connected to the inner tube 4 via the axle side bracket 10. Thus, the shock absorber main body 2 is interposed between the outer tube 3 and the inner tube 4, and when the shock absorber D expands and contracts, the piston rod 60 moves in and out of the cylinder 5 and the shock absorber main body 2 expands and contracts. The piston 6 moves up and down in the cylinder 5.
 シリンダ5の図1中上側は、ロッドガイド50で塞がれている。その一方、シリンダ5の下側は、バルブケース7で塞がれている。シリンダ5の内方であってロッドガイド50とバルブケース7との間をシリンダ5内とすると、シリンダ5内は、ピストン6で伸側室L1と圧側室L2とに区画されている。伸側室L1と圧側室L2には、それぞれ作動油が充填されている。ピストン6には、伸側室L1と圧側室L2とを連通する減衰通路6aが形成されている。減衰通路6aには、減衰通路6aを通って伸側室L1と圧側室L2との間を移動する作動油の流れに抵抗を与える減衰要素6bが設けられている。 The upper side of the cylinder 5 in FIG. 1 is closed by a rod guide 50. On the other hand, the lower side of the cylinder 5 is closed by a valve case 7. Assuming that the cylinder 5 is inward and the space between the rod guide 50 and the valve case 7 is in the cylinder 5, the inside of the cylinder 5 is divided by the piston 6 into an expansion side chamber L 1 and a pressure side chamber L 2. The hydraulic oil is filled in the expansion side chamber L1 and the pressure side chamber L2, respectively. The piston 6 is formed with a damping passage 6a that communicates the expansion side chamber L1 with the pressure side chamber L2. The damping passage 6a is provided with a damping element 6b that resists the flow of hydraulic fluid moving between the expansion side chamber L1 and the pressure side chamber L2 through the damping path 6a.
 つづいて、シリンダ5外には、チューブ部材1との間にリザーバRが形成されている。当該リザーバRには、作動油が貯留されるとともに、その液面上方に気体が充填されている。リザーバRにおいて、作動油が貯留された部分を液溜室L3、気体が充填された部分を気室Gとする。 Subsequently, a reservoir R is formed outside the cylinder 5 with the tube member 1. The reservoir R stores hydraulic oil and is filled with a gas above the liquid surface. In the reservoir R, a portion where hydraulic oil is stored is referred to as a liquid reservoir L3, and a portion filled with a gas is referred to as an air chamber G.
 バルブケース7には、圧側室L2と液溜室L3とを連通する吸込通路7aと排出通路7bが形成されている。吸込通路7aには、吸込通路7aを液溜室L3から圧側室L2へ向かう作動油の流れを許容するとともに、その逆向きの流れを阻止するチェックバルブ7cが設けられている。その一方、排出通路7bには、排出通路7bを通って圧側室L2と液溜室L3との間を移動する作動油の流れに抵抗を与える減衰要素7dが設けられている。 In the valve case 7, a suction passage 7a and a discharge passage 7b are formed, which communicate the pressure side chamber L2 and the liquid storage chamber L3. The suction passage 7a is provided with a check valve 7c that allows the flow of hydraulic oil from the liquid storage chamber L3 to the pressure side chamber L2 and blocks the flow in the opposite direction. On the other hand, the discharge passage 7b is provided with a damping element 7d that resists the flow of hydraulic fluid moving between the pressure side chamber L2 and the liquid storage chamber L3 through the discharge passage 7b.
 上記構成によれば、緩衝器Dの伸長時にピストンロッド60がシリンダ5から退出して緩衝器本体2が伸長し、ピストン6がシリンダ5内を図1中上方へ移動して伸側室L1を圧縮すると、伸側室L1の作動油が減衰通路6aを通って圧側室L2へ移動する。当該作動油の流れに対しては、減衰要素6bにより抵抗が付与されるので、緩衝器Dの伸長時には伸側室L1の圧力が上昇し、緩衝器本体2が伸長作動を抑制する減衰力を発揮する。 According to the above configuration, when the shock absorber D extends, the piston rod 60 withdraws from the cylinder 5 and the shock absorber main body 2 extends, and the piston 6 moves upward in the cylinder 5 in FIG. 1 to compress the expansion chamber L1. Then, the hydraulic oil in the expansion side chamber L1 moves to the pressure side chamber L2 through the damping passage 6a. Since the damping element 6b applies resistance to the flow of the hydraulic fluid, the pressure of the expansion chamber L1 increases when the shock absorber D is extended, and the shock absorber body 2 exerts a damping force that suppresses the extension operation. Do.
 反対に、緩衝器Dの収縮時にピストンロッド60がシリンダ5内へ進入して緩衝器本体2が収縮し、ピストン6がシリンダ5内を図1中下方へ移動して圧側室L2を圧縮すると、圧側室L2の作動油が減衰通路6aと排出通路7bを通って伸側室L1と液溜室L3へ移動する。これらの作動油の流れに対しては、減衰要素6b,7dによりそれぞれ抵抗が付与されるので、緩衝器Dの収縮時には圧側室L2の圧力が上昇し、緩衝器本体2が収縮作動を抑制する減衰力を発揮する。 Conversely, when the shock absorber D contracts, the piston rod 60 enters the cylinder 5 and the shock absorber main body 2 contracts, and the piston 6 moves downward in the cylinder 5 in FIG. 1 to compress the pressure chamber L2. The hydraulic oil in the pressure side chamber L2 moves to the expansion side chamber L1 and the liquid reservoir chamber L3 through the damping passage 6a and the discharge passage 7b. Since the resistances of the hydraulic fluid are given by the damping elements 6b and 7d, respectively, the pressure of the pressure side chamber L2 rises when the shock absorber D contracts, and the shock absorber main body 2 suppresses the contraction operation. Demonstrate damping force.
 このように、緩衝器Dでは、伸縮作動に伴い作動油がシリンダ5内、又はシリンダ5内とリザーバRとの間を流れ、当該作動油の流れに減衰要素6b,7dで抵抗を与えて減衰力が発生するようになっている。なお、緩衝器Dの伸縮時に作動油の流れる流路の構成は、適宜変更できるとともに、減衰要素6b,7dの構成も、適宜変更できる。例えば、減衰要素6b,7dとして、オリフィス、チョーク、バルブ等を利用できる。 Thus, in the shock absorber D, the hydraulic fluid flows in the cylinder 5 or between the cylinder 5 and the reservoir R along with the extension operation, and the flow of the hydraulic fluid is damped by giving resistance to the flow of the hydraulic fluid by the damping elements 6b and 7d. Force is supposed to be generated. In addition, while being able to change suitably the structure of the flow path through which hydraulic fluid flows at the time of expansion-contraction of the buffer D, the structure of damping element 6b, 7d can also be changed suitably. For example, an orifice, a choke, a valve or the like can be used as the damping elements 6b and 7d.
 また、緩衝器Dの伸長時には、チェックバルブ7cが開き、シリンダ5から退出したピストンロッド体積分の作動油が吸込通路7aを通ってリザーバRから圧側室L2へ供給される。反対に、緩衝器Dの収縮時には、シリンダ5内へ進入したピストンロッド体積分の作動油が排出通路7bを通って圧側室L2からリザーバRへ排出される。このように、緩衝器Dでは、伸縮作動に伴いシリンダ5に出入りするピストンロッド60の体積をリザーバRで補償するようになっている。 Further, when the shock absorber D is extended, the check valve 7c is opened, and the hydraulic oil for the piston rod volume which has been withdrawn from the cylinder 5 is supplied from the reservoir R to the pressure side chamber L2 through the suction passage 7a. On the contrary, at the time of contraction of the shock absorber D, the working oil of the piston rod volume entering the cylinder 5 is discharged from the pressure side chamber L2 to the reservoir R through the discharge passage 7b. Thus, in the shock absorber D, the reservoir R compensates for the volume of the piston rod 60 that moves into and out of the cylinder 5 as the expansion and contraction operation is performed.
 つづいて、リザーバRの気室Gに充填される気体は、ヘリウムである。そして、当該気室Gを有して気体ばねAが形成されており、この気体ばねAは、緩衝器Dを伸長方向へ附勢して車体を弾性支持する懸架ばねとして機能する。 Subsequently, the gas filled in the air chamber G of the reservoir R is helium. A gas spring A is formed with the air chamber G, and the gas spring A functions as a suspension spring for urging the shock absorber D in the extension direction to elastically support the vehicle body.
 そして、緩衝器Dが伸長してインナーチューブ4がアウターチューブ3から退出すると、気室Gの容積が拡大して圧力が低下するので、気体ばねAの弾性力が低下する。反対に、緩衝器Dが収縮してインナーチューブ4がアウターチューブ3内へ進入すると、気室Gの容積が縮小して圧力が上昇するので、気体ばねAの弾性力が大きくなる。 Then, when the shock absorber D is extended and the inner tube 4 is withdrawn from the outer tube 3, the volume of the air chamber G is expanded and the pressure is decreased, so that the elastic force of the gas spring A is decreased. Conversely, when the shock absorber D contracts and the inner tube 4 enters the outer tube 3, the volume of the air chamber G decreases and the pressure rises, so the elastic force of the gas spring A increases.
 図2は、酸素(O)、窒素(N)、ヘリウム(He)の水に対する溶解度と温度との関係を示した図である。当該図からわかるように、酸素及び窒素と比較して、ヘリウムの溶解度は小さく、温度変化に対する溶解度の変化が小さい。また、窒素及び酸素の溶解度は、温度の上昇とともに減少するが、ヘリウムの溶解度は、高温になると若干大きくなる。油に対する気体の溶解度は、水に対する気体の溶解度より大きいものの、気体の種類による溶解度の温度依存特性は似た傾向を示すことが知られている。 FIG. 2 is a diagram showing the relationship between the solubility of oxygen (O 2 ), nitrogen (N 2 ) and helium (He) in water and the temperature. As can be seen from the figure, the solubility of helium is small and the change in solubility with temperature is small compared to oxygen and nitrogen. Also, the solubilities of nitrogen and oxygen decrease with increasing temperature, but the solubilities of helium increase slightly at higher temperatures. Although the solubility of gas in oil is greater than the solubility of gas in water, it is known that the temperature dependence of solubility by gas type has a similar tendency.
 つまり、ヘリウムは、酸素及び窒素と比較して、作動油に対して溶け難く、温度変化による溶解度の変化も小さい。また、酸素及び窒素の作動油に対する溶解度は、温度が上がると減少するが、ヘリウムの作動油に対する溶解度は、温度が上がると若干大きくなる。 That is, helium is less soluble in hydraulic oil than oxygen and nitrogen, and the change in solubility due to temperature change is also small. Also, the solubility of oxygen and nitrogen in hydraulic fluid decreases with increasing temperature, while the solubility of helium in hydraulic fluid increases slightly with increasing temperature.
 従来、緩衝器に作動油とともに充填する気体として、エアを利用するのが最も一般的であり、窒素を利用することもある。エアの組成は、約80%が窒素、約20%が酸素である。前述の通り、ヘリウムは、酸素及び窒素と比較して、作動油に溶け難い。このため、本実施の形態のようにヘリウムが充填された緩衝器Dでは、エア又は窒素が充填された従来の緩衝器と比較して、作動油中の溶存気体が減少する。 Conventionally, air is most commonly used as a gas with which the shock absorber is filled with the hydraulic oil, and nitrogen may also be used. The composition of air is about 80% nitrogen and about 20% oxygen. As mentioned above, helium is less soluble in hydraulic oil compared to oxygen and nitrogen. Therefore, in the case of the shock absorber D filled with helium as in the present embodiment, the dissolved gas in the hydraulic oil is reduced as compared with the conventional shock absorber filled with air or nitrogen.
 よって、本実施の形態の緩衝器Dによれば、従来の緩衝器と比較してキャビテーションの発生を抑制し、減衰力の発生応答性を良好にできる。さらに、ヘリウムは、比較的安価であり、入手も容易であるので、上記構成によれば、キャビテーション発生の抑制と、減衰力発生応答性の向上を安価且つ容易に実現できる。 Therefore, according to the shock absorber D of the present embodiment, the occurrence of cavitation can be suppressed and the occurrence response of the damping force can be made better as compared with the conventional shock absorber. Further, helium is relatively inexpensive and easily available, and therefore, according to the above configuration, the occurrence of cavitation can be suppressed and the improvement of damping force generation responsiveness can be realized inexpensively and easily.
 また、車両走行時の振動により作動油が撹拌されると、作動油中に溶けていた気体が分離して気泡となって発生するので緩衝器Dの内圧が上昇する。さらに、車両走行時の振動により緩衝器Dが作動すると温度が上昇するので、これによっても緩衝器Dの内圧が上昇する。このため、鞍乗型車両が走行を開始すると、緩衝器Dの内圧が上昇し、気体ばねAの弾性力が大きくなる傾向がある。 In addition, when the hydraulic oil is agitated by vibration during traveling of the vehicle, the gas dissolved in the hydraulic oil is separated and generated as air bubbles, so the internal pressure of the shock absorber D rises. Furthermore, since the temperature rises when the shock absorber D operates due to the vibration when the vehicle travels, the internal pressure of the shock absorber D also rises. For this reason, when the saddle-ride type vehicle starts traveling, the internal pressure of the shock absorber D is increased, and the elastic force of the gas spring A tends to be increased.
 加えて、窒素、及び酸素の溶解度は、温度上昇により減少するので、エア又は窒素が充填された従来の緩衝器では、鞍乗型車両が走行を開始して緩衝器の温度が上昇すると内圧上昇が助長される。このため、従来の緩衝器では、車両走行時に気体ばねの弾性力が大きくなって、乗り心地が変化してしまう。 In addition, since the solubility of nitrogen and oxygen decreases as the temperature rises, in the case of a conventional shock absorber filled with air or nitrogen, the internal pressure rises when the temperature of the shock absorber rises as the straddle-type vehicle starts to travel. Is promoted. For this reason, in the conventional shock absorber, the elastic force of the gas spring increases when the vehicle travels, and the riding comfort changes.
 これに対して、ヘリウムの溶解度は、温度上昇による変化が少なく、温度上昇によって若干大きくなるので、ヘリウムが充填された本実施の形態の緩衝器Dでは、鞍乗型車両が走行を開始して緩衝器Dの温度が上昇しても内圧上昇を抑制できる。このため、当該緩衝器Dでは、車両走行時に気体ばねAの弾性力の変化を抑制し、車両の乗り心地が変化するのを抑制できる。 On the other hand, since the solubility of helium is small due to the temperature rise and slightly increases with the temperature rise, the shock absorber D according to the present embodiment filled with helium starts traveling Even if the temperature of the shock absorber D rises, the rise in internal pressure can be suppressed. Therefore, in the shock absorber D, it is possible to suppress the change in the elastic force of the gas spring A when the vehicle is traveling, and to suppress the change in the ride comfort of the vehicle.
 特に、本実施の形態の緩衝器Dのように、気体ばねAが車体を弾性支持する懸架ばねとして機能する場合、コイルばねからなる懸架ばねを備えた緩衝器と比較して、気体ばねAの弾性力の変化が車両の乗り心地に与える影響が大きい。 In particular, when the gas spring A functions as a suspension spring that elastically supports the vehicle body as in the shock absorber D of the present embodiment, compared to a shock absorber having a suspension spring consisting of a coil spring, The change in the elastic force has a large effect on the ride quality of the vehicle.
 さらに、モトクロスでは、モトクロッサーと称される競技用車両で未舗装の周回コースを走行するので、車両走行時に緩衝器に激しい振動が加わる。このため、従来のエア又は窒素が充填された気室を有して構成された気体ばねを懸架ばねとした緩衝器をモトクロスで使用した場合、走行開始から数周で車両の乗り心地が悪くなる。この場合、ピットに戻って気室の圧力を調整し直さなければならず、走行中に対応できないので手間がかかる。 Furthermore, in motocross, since a traveling vehicle called motocrosser travels on an unpaved circuit course, a strong vibration is added to the shock absorber when the vehicle is traveling. For this reason, when a shock absorber using a conventional air spring or a gas spring configured to have an air chamber filled with nitrogen as a suspension spring is used as a motocross, the ride quality of the vehicle is degraded several laps after the start of traveling . In this case, it is necessary to return to the pit and adjust the pressure of the air chamber again, and it takes time and effort because it can not cope during traveling.
 これに対して、ヘリウムが充填された気室Gを有して構成された気体ばねAを懸架ばねとする緩衝器Dでは、前述のように、気体ばねAの弾性力の変化を抑制できるので、良好な乗り心地を維持できる。つまり、気体ばねAが車体を弾性支持する懸架ばねとして機能する場合であって、特に、緩衝器Dがモトクロスに利用される場合には、ヘリウムを充填するのが有効である。 On the other hand, in the shock absorber D having the gas spring A configured to have the air chamber G filled with helium as a suspension spring, as described above, the change in the elastic force of the gas spring A can be suppressed. , Can maintain a good ride. That is, in the case where the gas spring A functions as a suspension spring that elastically supports the vehicle body, it is particularly effective to fill with helium when the shock absorber D is used for motocross.
 さらに、気体ばねAを懸架ばねとして利用する場合、設定次第ではあるが、気室Gの圧力が15気圧(atm)程度まで上昇することもある。このような高圧環境下では、作動油と酸素が結びついて二酸化炭素が発生する可能性がある。二酸化炭素の溶解度は、酸素の溶解度より高いので、溶存気体がさらに多くなる虞がある。そこで、本実施の形態のように、緩衝器Dにヘリウムを充填しておくと、このような問題も生じない。 Furthermore, when the gas spring A is used as a suspension spring, the pressure in the air chamber G may rise to about 15 atm (atm), depending on the setting. Under such a high pressure environment, the hydraulic oil and oxygen may combine to generate carbon dioxide. Since the solubility of carbon dioxide is higher than the solubility of oxygen, there is a risk that dissolved gas may be further increased. Therefore, if the buffer D is filled with helium as in the present embodiment, such a problem does not occur.
 また、ヘリウムを充填する緩衝器Dでは、ヘリウムパージにより作動油中のエアを予めヘリウムに置換してから緩衝器Dに充填すると、作動油中の溶存気体をさらに少なくできる。このため、キャビテーションの発生を抑制し、減衰力応答性を良好にする上で有利である。 Further, in the shock absorber D filled with helium, if the air in the working oil is replaced with helium in advance by the helium purge and then the shock absorber D is filled, the dissolved gas in the working oil can be further reduced. For this reason, it is advantageous in suppressing the occurrence of cavitation and improving the damping force response.
 とはいえ、ヘリウムは、ゴムを透過する性質をもつ。さらに、ヘリウム分子は非常に小さいので、場合によっては金属をも透過することもある。加えて、緩衝器Dの伸長時にアウターチューブ3から退出したインナーチューブ4の外周面には、シール部材12によって油膜が形成されている。このため、外気に曝された油膜中のヘリウムが大気中に放出されるとともに、大気中の窒素、酸素等が油膜に溶ける。そして、当該油膜は、緩衝器Dの収縮時にアウターチューブ3内へ戻る。これらの事情から、緩衝器Dにヘリウムを充填したとしても、時間の経過、及び作動に伴いヘリウムが漏れ、ヘリウムとエアが置換されていく。 However, helium has the property of permeating rubber. Furthermore, helium molecules are so small that they can also penetrate metals in some cases. In addition, an oil film is formed by the seal member 12 on the outer peripheral surface of the inner tube 4 which is withdrawn from the outer tube 3 when the shock absorber D is extended. Therefore, helium in the oil film exposed to the outside air is released to the atmosphere, and nitrogen, oxygen and the like in the atmosphere are dissolved in the oil film. Then, the oil film returns into the outer tube 3 when the shock absorber D contracts. Under these circumstances, even if the shock absorber D is filled with helium, helium leaks with the passage of time and operation, and helium and air are replaced.
 さらに、気体ばねAを懸架ばねとして利用する本実施の形態の緩衝器Dでは、コイルばねからなる懸架ばねを備えた緩衝器と比較して気室Gの圧力が高く設定される。一定量の溶媒に溶ける気体の物質量は圧力に比例するので、圧力の高い緩衝器D内ではヘリウムが作動油に多く溶ける。そして、このようにヘリウムを多く含む作動油が緩衝器Dの伸長時に油膜として緩衝器D外へ持ち出されると、圧力低下によって溶解しきれなくなったヘリウムが大気中に放出されてしまう。 Furthermore, in the shock absorber D of the present embodiment in which the gas spring A is used as a suspension spring, the pressure in the air chamber G is set higher compared to a shock absorber provided with a suspension spring consisting of a coil spring. Since the amount of gas that is soluble in a certain amount of solvent is proportional to the pressure, a large amount of helium dissolves in the working oil in the high-pressure buffer D. Then, when the hydraulic oil containing a large amount of helium is carried out of the shock absorber D as an oil film at the time of extension of the shock absorber D, helium which can not be dissolved due to the pressure drop is released to the atmosphere.
 このため、ヘリウムを充填した緩衝器Dであって、特に、ヘリウムを充填した気室Gを有して構成された気体ばねAを懸架ばねとして利用する場合には、定期的にヘリウムを補充しながら使用する必要がある。よって、このような緩衝器は、メンテナンスが頻繁に行われる競技用車両、又は、気室圧力を自動調整するばね力調整装置等を備えた車両への利用に適している。なぜなら、これらの車両では、メンテナンス又は気室圧力の調整時にヘリウムを気室Gへ供給できるためである。 For this reason, it is a shock absorber D filled with helium, and in particular, when the gas spring A configured to have a gas chamber G filled with helium is used as a suspension spring, the helium is periodically replenished. While it is necessary to use. Therefore, such a shock absorber is suitable for use in a competition vehicle whose maintenance is frequently performed, or a vehicle provided with a spring force adjustment device or the like that automatically adjusts the pressure in the air chamber. This is because in these vehicles, helium can be supplied to the air chamber G at the time of maintenance or adjustment of the air chamber pressure.
 また、緩衝器D自体に気室Gへヘリウムを補充する補充装置を設けてもよい。この場合には、緩衝器Dの一般車両への適用が容易である。なお、充填装置は、如何なる構成であってもよいが、例えば、ヘリウムが充填されたタンクと、タンクと気室Gとを接続する通路と、気室G内の圧力に応じてタンクから気室Gへヘリウムを供給するバルブ等を有して構成されるとよい。 In addition, the shock absorber D itself may be provided with a replenishment device for replenishing helium to the air chamber G. In this case, application of the shock absorber D to a general vehicle is easy. The filling device may have any configuration, for example, a tank filled with helium, a passage connecting the tank and the air chamber G, and a pressure from the tank to the air chamber according to the pressure in the air chamber G It may be configured to have a valve or the like for supplying helium to G.
 また、本実施の形態のように、緩衝器Dがシリンダ5と、シリンダ5内に摺動自在に挿入されるピストン6と、一端がピストン6に連結されて他端がシリンダ5外へ突出するピストンロッド60と、シリンダ5内に連通されるリザーバRとを備え、気体がリザーバRで作動油の油面に接している場合、気体をヘリウムにするのが特に有効である。 Further, as in the present embodiment, the shock absorber D is connected to the cylinder 5, the piston 6 slidably inserted in the cylinder 5, and one end is connected to the piston 6 and the other end protrudes out of the cylinder 5 When the gas is in contact with the oil surface of the hydraulic fluid in the reservoir R, it is particularly effective to use helium as the gas, provided with the piston rod 60 and the reservoir R communicated in the cylinder 5.
 なぜなら、上記構成によれば、リザーバR内で作動油中の溶存エアをヘリウムに置換できるとともに、緩衝器Dの伸縮時にリザーバRとシリンダ5との間を作動油が行き来するので、リザーバRにヘリウムを入れておけばシリンダ5内の作動油中の溶存気体を減少させることができ、キャビテーションの発生防止、及び減衰力発生応答性の向上の効果を得られるためである。 Because, according to the above configuration, the dissolved air in the hydraulic oil can be replaced with helium in the reservoir R, and the hydraulic oil moves between the reservoir R and the cylinder 5 when the shock absorber D expands and contracts. If helium is contained, the dissolved gas in the hydraulic oil in the cylinder 5 can be reduced, and the effect of preventing the occurrence of cavitation and improving the response of generation of damping force can be obtained.
 なお、このような効果は、ヘリウムが充填される気室Gを懸架ばねに利用しない場合にも得られる。例えば、ロッドガイド50とキャップ11との間にコイルばねからなる懸架ばねを設け、最伸長時における気室Gの圧力を大気圧程度にしてもよい。 Such an effect can also be obtained when the air chamber G filled with helium is not used as a suspension spring. For example, a suspension spring consisting of a coil spring may be provided between the rod guide 50 and the cap 11, and the pressure of the air chamber G at the time of the maximum extension may be approximately atmospheric pressure.
 また、図3に示す第一の変形例に係る緩衝器D1のように、シリンダ5の外周に設けた外筒51とシリンダ5との間にリザーバRを形成し、それよりも外周側に第二の気室G1を形成するチャンバ8を設け、第二の気室G1を有して懸架ばねとして機能する気体ばねA1を構成してもよい。 Further, as in the shock absorber D1 according to the first modification shown in FIG. 3, the reservoir R is formed between the outer cylinder 51 provided on the outer periphery of the cylinder 5 and the cylinder 5, and A chamber 8 forming a second air chamber G1 may be provided, and a gas spring A1 having a second air chamber G1 and functioning as a suspension spring may be configured.
 当該構成によれば、リザーバR内の気室Gにヘリウムを充填すれば、リザーバR内で作動油中のエアをヘリウムに置換できる。このため、チャンバ8内の気室G1に充填する気体は、ヘリウム以外であってもよく、チャンバ8を廃してコイルばねからなる懸架ばねを設けてもよい。 According to the configuration, if the air chamber G in the reservoir R is filled with helium, the air in the hydraulic oil can be replaced with helium in the reservoir R. Therefore, the gas filling the air chamber G1 in the chamber 8 may be other than helium, and the chamber 8 may be eliminated and a suspension spring made of a coil spring may be provided.
 なお、チャンバ8内の気室G1にヘリウムを充填すると、緩衝器D1の伸長時にシリンダ5から退出したピストンロッド60の外周に形成される油膜を介して作動油中のエアとチャンバ8内のヘリウムが置換される。つまり、シリンダ5に出入りするピストンロッド60の外周に形成された気室にヘリウムを充填すれば、リザーバR内でヘリウムと作動油が接していなくても作動油中のエアをヘリウムに置換でき、作動油中の溶存気体を減少させられる。 Note that when the air chamber G1 in the chamber 8 is filled with helium, the air in the working oil and the helium in the chamber 8 via the oil film formed on the outer periphery of the piston rod 60 which is withdrawn from the cylinder 5 when the shock absorber D1 extends. Is replaced. That is, by filling the air chamber formed on the outer periphery of the piston rod 60 entering and exiting the cylinder 5 with helium, the air in the working oil can be replaced with helium even if the working oil is not in contact with the helium in the reservoir R Dissolved gas in hydraulic oil can be reduced.
 そこで、例えば、図4に示す第二の変形例に係る緩衝器D2のように、リザーバRの液溜室L3と気室Gをフリーピストン52で区画してもよい。また、図5に示す第三の変形例に係る緩衝器D3のように、リザーバRを廃し、シリンダ5内にフリーピストン53で区画した膨縮可能な気室G2でシリンダ5に出入りするピストンロッド60の体積補償をしてもよい。 Therefore, for example, as in a shock absorber D2 according to a second modified example shown in FIG. 4, the liquid storage chamber L3 of the reservoir R and the air chamber G may be partitioned by the free piston 52. Further, as in the shock absorber D3 according to the third modification shown in FIG. 5, the piston rod is removed from the reservoir R and enters and exits the cylinder 5 in the expandable air chamber G2 partitioned by the free piston 53 in the cylinder 5. 60 volume compensation may be performed.
 さらに、前述のように、ヘリウムは透過し易い性質をもつ。このため、ヘリウムが充填された気室と、作動油が充填された油室をフリーピストン、ブラダ、ベローズ等の可動隔壁で区画しても、気室内のヘリウムは、油室側へ移動できる。つまり、可動隔壁で油室と区画された気室にヘリウムを充填した場合であっても、作動油中のエアをヘリウムに徐々に置換でき、作動油中の溶存気体を減少させられる。 Furthermore, as mentioned above, helium is easy to permeate. For this reason, even if the air chamber filled with helium and the oil chamber filled with the working oil are partitioned by a movable piston such as a free piston, a bladder or a bellows, the helium in the air chamber can move to the oil chamber side. That is, even in the case where the air chamber partitioned from the oil chamber by the movable partition is filled with helium, the air in the working oil can be gradually replaced with helium, and the dissolved gas in the working oil can be reduced.
 そこで、例えば、図4に示す第二の変形例に係る緩衝器D2のシリンダ5に設けた連通孔5aを廃して気室Gをシリンダ5内外に区画するとともに、シリンダ5内の気室Gaにヘリウムを充填し、シリンダ5外の気室Gbにヘリウム以外の気体を充填してもよい。 Therefore, for example, the communication hole 5a provided in the cylinder 5 of the shock absorber D2 according to the second modification shown in FIG. 4 is eliminated to divide the air chamber G into the inside and outside of the cylinder 5, and to the air chamber Ga in the cylinder 5. Helium may be filled, and the air chamber Gb outside the cylinder 5 may be filled with a gas other than helium.
 また、図5に示す第三の変形例に係る緩衝器D3の気室G2にヘリウムを充填し、チャンバ8内にヘリウム以外の気体を充填したり、チャンバ8を廃し、気体ばねA1に替えてコイルばねからなる懸架ばねを設けたりしてもよい。 Further, helium is filled in the air chamber G2 of the shock absorber D3 according to the third modification shown in FIG. 5, and the chamber 8 is filled with a gas other than helium, or the chamber 8 is discarded, and the gas spring A1 is replaced A suspension spring consisting of a coil spring may be provided.
 なお、前述のように、フリーピストン52,53等の可動隔壁で油室と区画された気室Ga,G2にヘリウムを充填する場合には、ヘリウムの油室側への移動を促すため、気室Ga,G2内の圧力を高めるとよい。 As described above, when helium is filled in the air chambers Ga and G2 partitioned from the oil chamber by the movable partitions such as the free pistons 52 and 53, the movement of the helium to the oil chamber side is promoted. The pressure in the chambers Ga and G2 may be increased.
 また、図1,3-5に示した緩衝器D,D1,D2,D3では、ピストンロッド60がピストン6の片側へ延びていて、片ロッド型になっている。しかし、ピストンロッド60をピストン6の両側へ延ばして両ロッド型にしてもよい。さらに、緩衝器D,D1,D2,D3では、減衰力発生用の液体として作動油を利用しているが水でもよく、酸素、窒素、及びヘリウムの溶解度の温度依存特性が図2と類似する特性となる液体であれば、作動油、水以外の液体を利用してもよい。 Further, in the shock absorbers D, D1, D2 and D3 shown in FIGS. 1 and 3, the piston rod 60 extends to one side of the piston 6 and is of a single rod type. However, the piston rod 60 may be extended to both sides of the piston 6 to be a double rod type. Furthermore, in the shock absorbers D, D1, D2 and D3, although hydraulic oil is used as a liquid for generating damping force, water may be used, and the temperature dependence characteristics of the solubility of oxygen, nitrogen and helium are similar to FIG. As long as the liquid is a characteristic, a liquid other than hydraulic oil and water may be used.
 以上、本発明の好ましい実施の形態を詳細に説明したが、特許請求の範囲から逸脱しない限り、改造、変形及び変更が可能である。 While the preferred embodiments of the present invention have been described above in detail, modifications, variations and changes are possible without departing from the scope of the claims.
 本願は、2017年9月14日に日本国特許庁に出願された特願2017-176331に基づく優先権を主張し、この出願の全ての内容は参照により本明細書に組み込まれる。
 
The present application claims priority based on Japanese Patent Application No. 2017-176331 filed on September 14, 2017, to the Japanese Patent Office, and the entire contents of this application are incorporated herein by reference.

Claims (5)

  1.  緩衝器であって、
     伸縮時に生じる液体の流れに抵抗を与えて減衰力を発揮する緩衝器であって、
     内部にヘリウムが充填された気室が形成されている
     緩衝器。
    A shock absorber,
    A shock absorber that resists the flow of liquid generated during expansion and contraction and exerts a damping force,
    An air chamber filled with helium is formed inside.
  2.  請求項1に記載の緩衝器であって、
     シリンダと、
     前記シリンダ内に摺動自在に挿入されるピストンと、
     一端が前記ピストンに連結されて他端が前記シリンダ外へ突出するピストンロッドと、
     前記シリンダ内に連通されるリザーバとを備え、
     前記気室は、前記リザーバに形成されており、
     前記ヘリウムは、前記リザーバで液体の液面に接している
     緩衝器。
    The shock absorber according to claim 1, wherein
    With the cylinder,
    A piston slidably inserted in the cylinder;
    A piston rod having one end connected to the piston and the other end projecting out of the cylinder;
    And a reservoir in communication with the cylinder.
    The air chamber is formed in the reservoir,
    The helium is in contact with the liquid level in the reservoir.
  3.  請求項1に記載の緩衝器であって、
     車両における車体と車軸との間に介装されており、
     前記気室を有して気体ばねが構成されており、
     前記気体ばねは、前記車体を弾性支持する懸架ばねとして機能する
     緩衝器。
    The shock absorber according to claim 1, wherein
    It is interposed between the car body and the axle in the vehicle,
    A gas spring is configured to have the air chamber,
    The gas spring functions as a suspension spring that elastically supports the vehicle body.
  4.  請求項1に記載の緩衝器であって、
     前記気室へヘリウムを補充する補充装置を備える
     緩衝器。
    The shock absorber according to claim 1, wherein
    A buffer comprising a replenishment device for replenishing helium into the air chamber.
  5.  請求項1に記載の緩衝器であって、
     競技用車両に利用されている
     緩衝器。
     
    The shock absorber according to claim 1, wherein
    Shock absorbers used in racing vehicles.
PCT/JP2018/031703 2017-09-14 2018-08-28 Damper WO2019054169A1 (en)

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Publication number Priority date Publication date Assignee Title
CN113007265A (en) * 2021-03-19 2021-06-22 中国人民解放军92578部队 Membrane type molecular spring vibration isolation buffer

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Publication number Priority date Publication date Assignee Title
JP7510655B1 (en) 2024-01-28 2024-07-04 株式会社オリジナルボックス Front fork built-in hydraulic shock absorber

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Publication number Priority date Publication date Assignee Title
JPS57202034U (en) * 1981-06-19 1982-12-22
JPH0235232A (en) * 1989-06-29 1990-02-05 Nhk Spring Co Ltd Partition film between gas and liquid chamber of pressure vessel
JPH02236001A (en) * 1989-03-03 1990-09-18 Nhk Spring Co Ltd Accumulator
JP2015055328A (en) * 2013-09-13 2015-03-23 カヤバ工業株式会社 Single cylinder type hydraulic shock absorber

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Publication number Priority date Publication date Assignee Title
JPS57202034U (en) * 1981-06-19 1982-12-22
JPH02236001A (en) * 1989-03-03 1990-09-18 Nhk Spring Co Ltd Accumulator
JPH0235232A (en) * 1989-06-29 1990-02-05 Nhk Spring Co Ltd Partition film between gas and liquid chamber of pressure vessel
JP2015055328A (en) * 2013-09-13 2015-03-23 カヤバ工業株式会社 Single cylinder type hydraulic shock absorber

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113007265A (en) * 2021-03-19 2021-06-22 中国人民解放军92578部队 Membrane type molecular spring vibration isolation buffer

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