JP2011236936A - Pneumatic shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic shock absorber which prevents leakage of a sealed gas and permanently guarantees expansion operability, by guaranteeing the quantity of oil stored in an oil reservoir recess.SOLUTION: The pneumatic shock absorber includes: an oil reservoir recess part R for storing a lubricating oil attached to the outer periphery of a rod body 2 penetrating its an axial core part to a rod guide 3 part having a rod guide 3 for closing the upper end of a cylinder which seals an appropriate gas; and a second check seal S2 which is positioned under the oil reservoir recess and made sliding contact with an outer periphery of a rod body 2 in order to prevent the leakage of the lubricating oil in the oil reservoir recess to the inside of the cylinder body 1. The oil reservoir recess part R, formed into a cylinder having a bottom, is disposed under the rod guide 3 and formed in an oil reservoir case 4 where the rod body 2 is penetrating through. A second check seal S2 is disposed at a bottom of the oil reservoir case 4 while a seal S3 for dynamic pressure control is connected in series under the second check seal S2.

Description

  The present invention relates to a pneumatic shock absorber, and more particularly to an improvement of a pneumatic shock absorber used for a suspension device in a vehicle, for example.

  There have been various proposals for pneumatic shock absorbers used for suspension devices in vehicles. Among them, for example, the proposal disclosed in Patent Document 1 avoids leakage of sealed gas. Ensuring telescopic operation.

  That is, in the pneumatic shock absorber disclosed in Patent Document 1, for example, an appropriate gas such as an inert gas is used as a lower end side member, as is the case with a pneumatic shock absorber of a certain kind. A rod body, which is sealed at an appropriate pressure and is connected to the axle side of the vehicle and connected to the vehicle body side of the vehicle, is inserted into the cylinder so as to be able to appear and retract.

  In this pneumatic shock absorber, the upper end opening of the cylinder body is basically sealed with a rod guide that penetrates the rod body through the shaft core, and the portion having the rod guide, that is, the rod guide The portion has a first check seal that is in sliding contact with the outer periphery of the rod body, and an oil reservoir recess that passes through the shaft core portion below the first check seal, that is, closer to the cylinder body.

  In addition, in this pneumatic shock absorber, the rod guide portion allows communication between the oil reservoir recess R and the cylinder body 1 as shown in FIG. 5 which embodies the place disclosed in Patent Document 1. And a drain passage L that is disposed in the drain passage L to allow the fluid from the oil reservoir recess R to flow into the cylinder body 1, and vice versa. It has a check valve C that prevents inflow into the reservoir recess R.

  Therefore, in this pneumatic shock absorber, an air chamber (not shown) portion above the oil level O in the oil reservoir recess R can communicate with the cylinder body 1, and at this time, FIG. As shown in the figure, even if the position of the oil level O in the oil sump recess R is lowered or not shown, the oil sump is not shown, even if the position of the oil level O in the oil sump recess R is most elevated. When the recess R has an abnormally high pressure, the abnormally high pressure can be released into the cylinder body 1.

  As a result, in this pneumatic shock absorber, the abnormally high pressure in the oil reservoir recess R can be released into the cylinder body 1, so that at least the check seal disposed above the oil reservoir recess R, that is, It is possible to avoid leakage of the sealed gas to the outside due to a failure such as damage in the first check seal S1 that is disposed in the rod guide 3 portion and slides the inner periphery to the outer periphery of the rod body 2.

  On the other hand, in this pneumatic shock absorber, the lubricating oil accommodated in the oil reservoir recess R adheres to the outer periphery of the rod body 2 to form a lubricating oil film on the outer periphery of the rod body 2. The slidability at the time of expansion / contraction operation of the pneumatic shock absorber, that is, the pneumatic shock absorber is ensured.

  In this pneumatic shock absorber, the drain passage L allows the fluid from the oil reservoir recess R to flow into the cylinder body 1, but the fluid from the cylinder body 1 is reversed. Since the check valve C is provided to prevent the inflow into the oil sump recess R, even if the gas as the fluid in the cylinder body 1 contains foreign matter such as metal powder, the gas entering the foreign matter flows into the oil sump recess R. Therefore, the deterioration of the lubricating oil accommodated in the oil reservoir recess R due to the inclusion of foreign matter is prevented.

  As a result, in the proposal disclosed in the above-mentioned Patent Document 1, it is possible to permanently guarantee the expansion and contraction operability in the pneumatic shock absorber while avoiding the leakage of the gas sealed in the pneumatic shock absorber. become.

Japanese Patent Laying-Open No. 2009-41766 (see abstract, paragraph 0030 in the specification, FIG. 1)

  However, the above-described pneumatic shock absorber disclosed in Patent Document 1 is basically not problematic in that the leakage prevention of the enclosed gas and the expansion and contraction operability are ensured, but the actual use is not In consideration, there is a possibility that it is pointed out that there is a minor defect.

  In other words, the pneumatic shock absorber described above has the second check seal S <b> 2 that is positioned below the oil reservoir recess R in the rod guide 3 portion and whose inner circumference is in sliding contact with the outer circumference of the rod body 2.

  Therefore, since this pneumatic shock absorber has the second check seal S2 below the oil reservoir recess R, the lubricating oil from the oil reservoir recess R passes through the gap with the rod body 2. The required amount of lubricating oil stored in the oil reservoir recess R can be ensured without being discharged into the cylinder body 1.

  However, there is a concern that the pressure of the cylinder body 1 reaches the first check seal S1, for example, because the speed at which the piston portion P rises in the cylinder body 1 becomes high.

  If this is repeated, the durability of the first check seal S1 is reduced, and the first check seal S1 cannot perform a predetermined sealing function, and there is a risk of leakage of the enclosed gas to the outside. There is.

  The present invention has been developed in view of the above-described circumstances, and its object is to prevent the leakage of the sealed gas, as well as to ensure the amount of lubricating oil contained in the oil reservoir recess. The object is to provide a pneumatic shock absorber that is optimally secured to permanently guarantee the stretchability and to be expected to improve its versatility.

  In order to achieve the above-described object, the structure of the pneumatic shock absorber according to the present invention basically includes a cylinder body that is sealed with an appropriate gas and is used as an axle side member in a vehicle, and can appear and disappear in the cylinder body. A rod body that is inserted into the vehicle body and serves as a vehicle body side member of the vehicle, and a rod side chamber and a piston side chamber that are slidably housed in the cylinder body and defined in the cylinder body while being held at the tip of the rod body A piston portion that allows communication, and performs a predetermined damping action during expansion / contraction operation in which the piston portion slides in the cylinder body, while closing the upper end opening of the cylinder body while passing the rod body through the shaft core portion. The first check system has a rod guide and a rod guide portion having the rod guide is in sliding contact with the outer periphery of the rod body to prevent leakage of sealed gas in the cylinder body to the outside. And an oil reservoir recess that contains lubricating oil attached to the outer periphery of the rod body penetrating the shaft core portion, and the lubricant in the oil reservoir recess that slides on the outer periphery of the rod body while being positioned below the oil reservoir recess. A second check seal that prevents leakage of the oil into the cylinder body, a drain passage that allows the oil reservoir recess to communicate with the cylinder body, and a fluid that is disposed in the drain passage from the oil reservoir recess to the cylinder body. And a check valve that allows the fluid from the cylinder body to flow into the oil reservoir recess.

  In the pneumatic shock absorber, the oil reservoir recess is formed inside the oil reservoir case that is disposed below the rod guide and penetrates the rod body through the shaft core while being formed in a bottomed cylindrical shape. The second check seal is disposed at the bottom of the oil sump case, and the dynamic pressure control seal is arranged in series below the second check seal.

  Therefore, in the present invention, since the rod guide portion having the rod guide that closes the upper end opening of the cylinder body has the oil reservoir recess that contains the lubricating oil while penetrating the rod body in the shaft core portion, the rod body The formation of a lubricating oil film on the outer periphery of the cylinder body is ensured, and the slidability when the rod body protrudes and retracts from the cylinder body, that is, the expansion and contraction operability in the pneumatic shock absorber is ensured.

  In this invention, the drain passage that allows the oil reservoir recess and the cylinder body to communicate with each other is provided, and the drain passage allows the fluid from the oil reservoir recess to flow into the cylinder body. Since there is a check valve that prevents the fluid from flowing into the oil reservoir recess, the abnormal high pressure in the oil reservoir recess is released into the cylinder body, and the first check seal above the oil reservoir recess is damaged. Lubricating oil contained in the oil reservoir recess can be prevented by preventing leakage of the sealed gas due to a failure and preventing foreign matter that may be mixed into the fluid gas from the cylinder body from flowing into the oil reservoir recess. It is possible to prevent deterioration due to contamination of foreign matter.

  In the present invention, since the second check seal is disposed at the bottom of the oil sump case that forms the oil sump recess on the inside, the lubricating oil contained in the oil sump recess is between the rod body. This prevents the cylinder from flowing out through the gap.

  Further, in the present invention, since the dynamic pressure control seal is arranged in series below the second check seal, so-called high pressure from the cylinder body does not act on the second check seal, and this second check seal The seal function of the check seal can be permanently guaranteed.

  Incidentally, the check valve consists of a leaf valve that closes the downstream end of the drain passage that opens to the bottom surface of the oil sump case so that it can be opened, and this leaf valve applies a deflection load while making the bottom surface of the oil sump case the valve seat surface. If the adhesion to the valve seat surface is improved, the gas mixed with foreign matter in the cylinder body cannot flow into the drain passage between the leaf valve and the bottom of the oil sump case, Lubricating oil contained in the oil reservoir recess is not deteriorated by foreign matter.

It is a partial longitudinal cross-section front view which fractures | ruptures and shows the pneumatic shock absorber by this invention. FIG. 2 is a partial semi-longitudinal longitudinal cross-sectional view showing an enlarged head end that is an upper part of a cylinder body in the pneumatic shock absorber of FIG. 1. It is a partial expanded longitudinal sectional view which shows the structure which adds a bending load to the leaf valve which is a check valve, (A) shows the state in which the valve seat surface has a level | step difference, (B) shows that the leaf valve connected the thickness member continuously Indicates the state to perform. It is a partial expanded longitudinal cross-sectional view which shows the other structure which adds a bending load to the leaf valve which is a check valve. It is a figure which shows the pneumatic shock absorber made into a prior art example similarly to FIG.

  Hereinafter, the present invention will be described based on the illustrated embodiment. As shown in FIG. 1, the pneumatic shock absorber according to the present invention is basically shown in FIG. It has the same configuration as the pneumatic shock absorber.

  Therefore, in the place shown in FIG. 1, the same reference numerals are given in the figure where the configuration is the same as that shown in FIG. 5, and detailed description thereof is omitted unless necessary.

  That is, first, the pneumatic shock absorber according to the present invention is in this embodiment, and although it is not shown in detail, it is used for a suspension device in a vehicle. Leakage is avoided.

  For this reason, the pneumatic shock absorber includes a cylinder body 1 that is sealed with an appropriate gas under an appropriate pressure and serves as an axle-side member of the vehicle, and is inserted into the cylinder body 1 so as to be able to appear and retract, and the vehicle body side of the vehicle. The rod body 2 as a member, and the rod body 2 is slidably received in the cylinder body 1 while being held at the tip part which is the lower end in the figure of the rod body 2, and the rod side chamber R1 and the piston are accommodated in the cylinder body 1 It has a piston part P that defines the side chamber R2.

  In this pneumatic shock absorber, the piston portion P allows the communication between the rod-side chamber R1 and the piston-side chamber R2 when moving up and down sliding in the cylinder body 1, and has a predetermined damping action during the communication. There are an extension side damping means and a compression side damping means that enable the realization of the above, and each of the damping means comprises an extension side damping valve V1 and a compression side damping valve V2.

  Incidentally, in this pneumatic shock absorber, an appropriate gas, such as an inert gas, is enclosed in the cylinder body 1 under an appropriate pressure, so that the pressure receiving pressure in the rod side chamber R1 and the piston side chamber R2 is received. From the area difference, the piston part P is urged in the direction of rising in the cylinder body 1, that is, in the extending direction, and has a rod reaction force based on the enclosed atmospheric pressure.

  Next, in this pneumatic shock absorber, the upper end opening of the cylinder body 1 is basically a rod guide that allows the rod body 2 to pass through the shaft core portion under the arrangement of the bush B that ensures slidability. 3, an oil reservoir case 4 that forms an oil reservoir recess R, which will be described later, closes the upper end opening of the cylinder body 1.

  At this time, the oil sump case 4 is shown in the figure, is formed in a bottomed cylindrical shape that allows the rod body 2 to pass through the shaft core portion, and contains lubricating oil in an inner recess (not shown). Lubricating oil attaches to the outer periphery of the rod body 2 to form a lubricating oil film on the outer periphery of the rod body 2.

  By the way, the oil sump case 4 is shown in the figure, and the outer periphery on the lower end side is screwed to the inner periphery of the upper end portion of the cylinder body 1. At this time, the upper end outer flange portion 4 a and the cylinder body 1 The lower end inner flange portion 5a of the extending portion 5 formed in a substantially cylindrical shape that is an upper portion of the cylinder body 1 is sandwiched between the upper end and the upper end.

  Inside the extended portion 5, the rod guide 3 is accommodated in a state of being placed on the oil sump case 4, and a seal that allows the rod body 2 to pass through the shaft guide portion on the rod guide 3. The case 6 is accommodated in a position to be placed.

  By the way, this extending portion 5 has an oil reservoir case 4, a rod guide 3 and a seal case 6 sequentially housed inside before the extension to the upper end portion of the cylinder body 1, and the upper end portion 5b is placed on the inner side. The rod body 2 is formed so as to pass through the shaft core portion in this state.

  A cap 7 that is formed in a headed cylinder shape and is inserted into the shaft core portion through the extension portion 5 is screwed. An inner peripheral side portion of the cap 7 is formed in the seal case 6. The outer groove S formed in the peripheral upper end is covered with the outer seal S of the housing so that the outer seal S is prevented from coming out of the accommodation position.

  Incidentally, the outer seal S scrapes off dust attached to the outer periphery of the rod body 2 when the rod body 2 is immersed in the cylinder body 1, and the seal case 6 is an annular formed at the lower end on the inner periphery side. The first check seal S1 is accommodated in the groove 6b, and the first check seal S1 prevents the gas sealed in the cylinder body 1 from leaking to the outside while the bush B is exchanged. The attached lubricating oil film is scraped off and left on the outer periphery of the rod body 2 that rises in this manner, and the lubricating oil is prevented from protruding outside and leaking out the lubricating oil while attached to the outer periphery of the rod body 2.

  Further, a seal 6 c is interposed on the outer periphery of the seal case 6, and fluid from the inside of the cylinder body 1 leaks outside through the extended portion 5, the oil reservoir case 4, and the outer periphery of the rod guide 3. To prevent it.

  In the pneumatic shock absorber formed as described above, the oil sump case 4 has a drain passage L that allows communication between the oil sump recess R and the inside of the cylinder body 1. A check valve C that allows the fluid out of the reservoir recess R to flow into the cylinder body 1 but the opposite flow, that is, prevents the fluid from flowing into the oil reservoir recess R from the cylinder body 1 is provided. It is arranged.

  First, as shown in FIG. 2, the oil sump case 4 is formed in a bottomed cylindrical shape, and the rod body 2 is passed through the shaft core portion with the second check seal S2 disposed, and the oil sump portion on the inner side. And contains lubricating oil.

  At this time, when the rod body 2 enters the cylinder body 1, the second check seal S <b> 2 scrapes off the lubricating oil film attached to the outer periphery of the rod body 2 and leaves it in the oil reservoir recess R. The lubricating oil is prevented from leaching into the rod side chamber R1 in the cylinder body 1 while attached to the outer periphery of the rod body 2, that is, from flowing out.

  The drain passage L (see FIG. 1) is formed in the radial direction at the upper end portion of the cylinder portion (not shown) of the oil sump case 4, that is, at the upper end outer flange portion 4a as shown in FIG. And a notch groove 4b whose inner end communicates with the oil reservoir recess R, and a vertical hole whose upper end communicates with the above-described notch groove 4b by being opened in the axial direction which is the vertical direction in the figure in the cylindrical portion of the oil reservoir case 4. It consists of holes 4c.

  Further, the inner end of the notch groove 4b opens above the oil surface O in the oil reservoir recess R, that is, to an air chamber portion not shown.

  Therefore, in this drain passage L, for example, when the lubricating oil accommodated in the oil sump recess R overflows, the overflowing lubricating oil is allowed to flow into the cylinder body 1. As a result, by having the drain passage L, it is possible to present a state in which an appropriate amount of lubricating oil is accommodated in the oil reservoir recess R.

  On the other hand, the check valve C (see FIG. 1) is a leaf valve 10 according to the present invention, and the leaf valve 10 is, in other words, an appropriate measure, which is the downstream end of the drain passage L, that is, the vertical valve. The lower end opening of the hole 4c is closed so as to be openable from the rod side chamber R1 side in the cylinder body 1.

  Thus, since the check valve C includes the leaf valve 10, the configuration of the check valve 10 can be simplified. As a result, the cost of parts can be reduced, and the product in the pneumatic shock absorber which is the final product. Contributes to cost reduction.

  Incidentally, by arranging the check valve C in the drain passage L, it is possible to prevent the gas in the cylinder body 1 from flowing into the oil reservoir recess R, and as a result, the gas in the cylinder body 1 is extremely low. Even when a fine metal powder is mixed, it is possible to prevent the gas mixed with the metal powder from flowing into the oil reservoir recess R, and therefore it is possible to prevent the deterioration of the lubricating oil due to the mixing of the metal powder.

  By the way, in the present invention, as described above, foreign matter may be mixed in the lubricating oil accommodated in the oil reservoir recess R. Therefore, an attempt is made to deal with this, but the necessity is as follows. .

  That is, there are various types of what is called a pneumatic shock absorber. For example, in a pneumatic shock absorber called a gas spring, the lubricating oil accommodated in the oil reservoir recess R or the like is used. There is no need to worry about foreign matter getting inside.

  In other words, looking at the actual use of the gas spring, for example, when it is used as a smoke damper, it is rare that the damper expands and contracts, and the so-called expansion and contraction operation continues continuously for a long time. It is never done.

  Further, even when the gas spring is a seat damper or a backrest damper, the pneumatic shock absorber as the damper is not frequently expanded and contracted.

  Therefore, in the above-mentioned smoke damper, seat damper, or pneumatic damper used as a backrest damper, since it does not frequently extend and contract continuously for a long time, there is an opportunity to get dirty other than denature the lubricating oil. Therefore, it can be said that there is no need to consider measures against the contamination of the lubricating oil.

  On the other hand, the pneumatic shock absorber may extend and contract for a long time when the pneumatic shock absorber constitutes a suspension device in a vehicle. Since the piston portion P frequently reciprocates and sometimes a lateral force acts on the pneumatic shock absorber, it is difficult to say that sliding of the piston portion P in the cylinder body 1 is always low in resistance. Therefore, it can be easily assumed that dust, that is, foreign matter is generated and drifts.

  Accordingly, as the object of the present invention, when the pneumatic shock absorber constitutes a suspension device in a vehicle, the foreign matter is mixed into the lubricating oil contained in the oil reservoir recess R. There is a need to stop.

  From the above, in the present invention, it is assumed that the drain passage L has the check valve C in order to prevent foreign matter from entering the oil reservoir recess R as described above.

  Under the premise as described above, in the present invention, the leaf valve 10 constituting the check valve C is applied with a deflection load in advance by an appropriate measure, and the deflection load is applied in advance, so-called valve seat. As a result, it is ensured that the check valve C functions sufficiently as a check valve.

  In view of this, in the present invention, the leaf valve 10 constituting the check valve C is preliminarily applied with a deflection load. As a specific measure thereof, as shown in FIG. 2 and FIG. Although the contact member 8 is used, the contact member 8 is also a member in which the dynamic pressure control seal S3 is disposed as described later.

  That is, first, the contact member 8 is a member for fixing the above-described second check seal S2 at a predetermined position, and is formed in an annular shape that allows the rod body 2 to pass through the shaft core portion. However, it is adjacent to the bottom of the oil sump case 4.

  That is, the oil sump case 4 and the contact member 8 are formed so as to be divided, so that when the contact member 8 is separated from the bottom of the oil sump case 4, the inner periphery of the oil sump case 4. It becomes easy to accommodate the second check seal S2 in the annular groove 4d formed in the lower side portion.

  On the other hand, this abutting member 8 is shown in the figure, is formed thick, and has a dynamic pressure control seal S3 at the thick portion at the inner peripheral side end, and this dynamic pressure control seal S3. Is in sliding contact with the outer periphery of the rod body 2.

  As a result, for example, when this pneumatic shock absorber is extended at a high speed, the high pressure action acts on the first check seal S1 when the rod side chamber R1 is in a sudden high pressure state. This can prevent the first check seal S1 from being deteriorated unnecessarily.

  Incidentally, since the second check seal S2 can apply the high pressure from the rod side chamber R1 to the oil reservoir recess R without resistance, the second check seal S2 is not deteriorated by the high pressure from the rod side chamber R1. .

  That is, as described above, there is a concern that the pressure of the cylinder body 1 reaches the first check seal S1 because, for example, the speed at which the piston portion P rises in the cylinder body 1 becomes high.

  If this is repeated, the durability of the first check seal S1 is reduced, and leakage of the enclosed gas to the outside cannot be prevented.

  Therefore, in the present invention, the above-mentioned dynamic pressure control seal S3 is arranged in series with the second check seal S2 above it, so that the high pressure in the cylinder body 1 is the first check seal. Blocks acting on S1.

  By the way, in order to connect the contact member 8 to the bottom of the oil sump case 4, it is assumed that a tightening bolt 12 is used as shown in FIG. 2. It is screwed into the bottom of the oil sump case 4 while being inserted.

  At this time, the abutting member 8 is formed when the proximal end portion of the leaf valve 10, that is, the leaf valve 10 is formed in an arc shape or a sector shape on the outer peripheral side portion which is the left side portion in FIG. 2, and when the leaf valve 10 is formed in an annular shape, the inner peripheral side end that is the right end in FIG. 2 is between the bottom of the oil sump case 4. Hold it.

  At this time, the bottom surface of the oil sump case 4 is set as the valve seat surface, and the outer peripheral side portion of the leaf valve 10, that is, the bent side portion is in close contact with the valve seat surface.

  In addition, a bending load is applied to the leaf valve 10 when closely attached to the valve seat surface, thereby improving the adhesion to the valve seat surface as compared with the case where no bending load is applied. The gas from the rod side chamber R1 cannot easily flow into the oil reservoir recess R through the drain passage L described above.

  In order to apply a bending load to the leaf valve 10, as a result, it is sufficient that the bending end portion of the leaf valve 10 is higher as a valve seat surface position than the base end portion on the fixed side.

  For example, the portion shown in FIG. 3 (A) is an enlarged view of the portion shown in FIG. 2, but a step 4e may be provided on the bottom surface of the oil sump case 4 as shown in FIG. 3 (A). In addition, as shown in FIG. 3B, a thick member 13 may be provided continuously so as to put a so-called clog at the bent end of the leaf valve 10.

  From the viewpoint of manufacturing parts, it is easier to connect the thickness member 13 to the outer peripheral side of the leaf valve 10 than the case where the step 4e is provided at the bottom of the oil sump case 4, and the manufacturing cost is reduced. It can be said that it is cheap.

By the way, even if a bending load is applied to the leaf valve 10 while using the contact member 8, the use of the tightening bolt 12 is omitted as shown in FIG. 4 instead of the embodiment shown in FIG. That is, in this embodiment, the contact member 8 is screwed to the bottom of the oil sump case 4, and a female screw 4 f is formed at the bottom of the oil sump case 4, so that the contact member 8 However, since the tightening bolt 12 is unnecessary, it can be said that it is advantageous from the viewpoint of reducing the number of parts.

  In the place shown in FIG. 4, a step 4e is provided at the bottom of the oil sump case 4, but instead of this, as shown in FIG. Needless to say, the bulb 10 may be provided with the thick member 13 connected to the outer peripheral side portion.

  Further, in this embodiment, the dynamic pressure control seal S3 is accommodated on the inner peripheral side portion of the contact member 8, and the annular groove portion 8b formed on the inner peripheral side upper end portion of the contact member 8. Since the second check seal S2 is housed in the second check seal S2, the second check seal S2 is arranged, that is, assembled into a predetermined position as compared with the embodiment shown in FIG. There is an advantage that becomes easier.

  As described above, in the pneumatic shock absorber according to the present invention, the check valve C disposed in the drain passage L includes the leaf valve 10 and a bending load is added to the leaf valve 10 in advance. Compared to the case where the adhesion of the leaf valve 10 to the bottom surface of the oil sump case 4 which is the valve seat surface is improved and no bending load is applied to the leaf valve 10 in advance, the metal powder which is a foreign substance in the cylinder body 1 The opportunity for the gas mixed in to flow into the oil reservoir recess R is greatly reduced, and the lubricating oil contained in the oil reservoir recess R is less likely to be deteriorated due to the inclusion of foreign matter, and the lubricity of the rod body 2 to the cylinder body 1 is improved. Guaranteed, the telescopic operation in the pneumatic shock absorber is permanently guaranteed.

  In the pneumatic shock absorber according to the present invention, the second check seal S2 is disposed at the bottom of the oil sump case 4 that forms the oil sump recess R on the inside. The lubricant contained in the reservoir recess R can be prevented from flowing into the cylinder body 1 through the gap between the rod body 2, and the amount of lubricant stored in the oil reservoir recess R can be maintained optimally. The slidability of the rod body 2 with respect to the cylinder body 1, that is, the expansion / contraction operability in the pneumatic shock absorber can be permanently secured.

  In the pneumatic shock absorber according to the present invention, the dynamic pressure control seal S3 is arranged in series below the second check seal S2, so that the high pressure in the cylinder body 1 is maintained at the first check seal S1. , The deterioration of the sealing function of the first check seal S1 can be avoided, and leakage of the sealed gas to the outside can be avoided permanently.

  As described above, the pneumatic shock absorber of the present invention is formed in a single cylinder type. However, from the point of view of the present invention, it has an outer cylinder outside the cylinder body 1, although not shown in the figure. The rod guide 3 may be formed as a double cylinder type in which a reservoir is set between the outer cylinder and the cylinder body 1. In this case, the rod guide 3 closes the upper ends of the cylinder body 1 and the outer cylinder, and this rod The downstream end of the drain passage L formed in the guide 3 and having an inner peripheral end that opens to the oil reservoir recess R opens to the reservoir.

  In addition, in the above description, the present invention is the pneumatic shock absorber. However, considering the intention of the present invention, as long as the main configuration is to use gas as the working fluid, the cylinder body 1 Of course, the present invention may be embodied in a pneumatic shock absorber having a lubricating oil for ensuring lubrication, and there is no difference in the function and effect in that case.

  In the above description, the case where the pneumatic shock absorber is set to the upright type has been described as an example including the one shown in the figure. However, the present invention intends, that is, in the oil reservoir recess R. From the viewpoint of improving the function of the check valve C provided in the communication drain passage L, it goes without saying that the pneumatic shock absorber may be set upside down.

  It is suitable for use in a suspension device in a vehicle, and particularly suitable for implementation in a pneumatic shock absorber in which fine metal powder may be mixed in a gas accommodated in a cylinder body as a working fluid.

DESCRIPTION OF SYMBOLS 1 Cylinder body 2 Rod body 3 Rod guide 4 Oil sump case 4a Upper end outer flange part 4b Notch groove 4c Vertical hole 4e Step 4f Female screw 5 Extension part 5a Lower end inner flange part 5b Upper end part 6 Seal cases 6a, 6b, 8b Annular Groove 6c Seal 7 Cap 8 Contact member 8a Male thread 10 Leaf valve 12 Tightening bolt 13 Thick member B Bush C Check valve L Drain passage O Oil level P Piston part R Oil reservoir recess R1 Rod side chamber R2 Piston side chamber S Outer seal S1 First check seal S2 Second check seal S3 Dynamic pressure control seal V1 Extension side damping valve V2 Pressure side damping valve

Claims (5)

  A cylinder body that is used as an axle side member in the vehicle by enclosing an appropriate gas, a rod body that is inserted into the cylinder body so as to be able to project and retract and is used as a vehicle body side member in the vehicle, and held at the tip of the rod body However, the rod side chamber defined in the cylinder body so as to be slidable and the piston portion allowing the communication between the piston side chamber and a piston portion sliding inside the cylinder body is provided during a telescopic operation. While having a damping action, it has a rod guide that closes the upper end opening of the cylinder body while penetrating the rod body through the shaft core portion, and the rod guide portion having the rod guide is in sliding contact with the outer periphery of the rod body. A first check seal that prevents leakage of the sealed gas to the outside and an oil reservoir recess that contains lubricating oil attached to the outer periphery of the rod body that penetrates the shaft core portion A second check seal that slides on the outer periphery of the rod body while being positioned below the oil reservoir recess to prevent leakage of the lubricating oil in the oil reservoir recess into the cylinder, and communication between the oil reservoir recess and the cylinder And a check valve that is disposed in the drain passage and allows a fluid to flow out from the oil reservoir recess into the cylinder body but prevents the fluid from flowing into the oil reservoir recess from the cylinder body. In the pneumatic shock absorber, the oil reservoir recess is formed inside the bottom of the oil reservoir case that is disposed below the rod guide and penetrates the rod body through the shaft core while being formed in a bottomed cylindrical shape. In addition, the second check seal is disposed at the bottom of the oil sump case, and a dynamic pressure control seal is connected in series below the second check seal. Shock absorber.   The check valve is composed of a leaf valve that closes the downstream end of the drain passage that opens to the bottom surface of the oil sump case so that the downstream side can be opened, and the leaf valve is subjected to a bending load while the bottom surface of the oil sump case is the valve seat surface. The pneumatic shock absorber according to claim 1, wherein adhesion to the valve seat surface is improved.   The pneumatic shock absorber according to claim 1 or 2, wherein the dynamic pressure control seal is disposed at the bottom of the oil sump case.   3. The pneumatic shock absorber according to claim 1, wherein the dynamic pressure control seal is disposed on an abutting member that abuts against the bottom of the oil sump case from the inside of the cylinder body.   The pneumatic shock absorber according to claim 4, wherein the contact member is screwed to the bottom of the oil sump case, or is brought into contact with the bottom of the oil sump case under the use of a bolt.

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