JP2009097552A - Pneumatic shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic shock absorber having a new lubricating structure capable of lubricating a sliding part between a piston and a cylinder without making lubricating oil reciprocate between a rod side chamber and a piston side chamber. <P>SOLUTION: This pneumatic shock absorber has the piston 5 movably inserted into the cylinder 3 via a piston rod 6 and partitioning the inside of this cylinder 3 into the rod side chamber 40 and the piston side chamber 50, and a communicating passage 20 making the rod side chamber 40 communicate with the piston side chamber 50, and is provided by filling working gas into the cylinder 3. A damping force generating base valve V rising from a bottom 3a is arranged in the piston side chamber 50, and one end of the communicating passage 20 communicates with the piston side chamber 50 via the base valve V. A piston side seal member 7 is arranged at an outer peripheral part of the piston 5 for sealing a part between the piston 5 and the cylinder 3 while slidingly contacting with the inner peripheral surface of the cylinder 3. The lubricating oil O is also injected into the rod side chamber 40. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an improvement in a pneumatic shock absorber that can be used in a suspension device of a vehicle such as an automobile or an industrial vehicle.

  Conventionally, as this kind of pneumatic shock absorber, those of various structures can be exemplified, but as the pneumatic shock absorber used in a vehicle suspension device, the one shown in Patent Document 1 is exemplified. Can do.

  That is, as shown in FIG. 3, the upper and lower ends of the cylinder 42 formed in a cylindrical shape are respectively closed by a head member (corresponding to a rod guide of the present invention) 43 and a bottom member 44, and in the cylinder 42. The cylinder 42 is partitioned into a rod side chamber 40 and a piston side chamber 50 by a piston 45 slidably inserted.

  The head member 43 is formed in an annular shape, and has a bearing 46 that pivotally supports the piston rod 51 and an accumulation recess 47 that opens from the upper end side.

  The cylinder 42 is covered with a bottomed cylindrical outer cylinder 41 disposed outside the cylinder 42, and an annular seal is formed on the inner peripheral side at the opening end which is the upper end of the outer cylinder 41 in the figure. A sealing member 49 that holds 48 is fixed in a state of being stacked on the head member 43.

  The lower end of the annular seal 48 protruding from the sealing member 49 is disposed in the storage recess 47 of the head member 43, and the oil storage chamber S is formed by the storage recess 47, the sealing member 49, and the piston rod 51. Is defined.

  The piston rod 51 protruding from the cylinder 42 is slidably inserted into the bearing 46 of the head member 43 on the inner peripheral side of the annular seal 48, and the annular seal 48 is slid by a predetermined compression force. It is press-contacted to the outer peripheral surface.

  Therefore, the piston rod 51 passes through the oil storage chamber S, and this oil storage chamber S faces the sliding portion between the piston rod 51 and the annular seal 48.

  Further, the oil storage chamber S is communicated with the rod side chamber 40 by a connection path 52 provided in the head member 43, and is communicated with the circulation path R by another connection path 53.

  The piston 45 is formed with a pressure side communication passage 45a and an extension side communication passage 45b that communicate the rod side chamber 40 and the piston side chamber 50, respectively.

  The pressure side communication path 45a is provided with a pressure side damping valve 56 and a pressure side check valve 56a that allows the flow of the gas G only from the piston side chamber 50 to the rod side chamber 40. An extension side damping valve 57 and an extension side check valve 57a that allows the flow of gas G and lubricating oil O only from the rod side chamber 40 to the piston side chamber 50 are provided. In this case, the damping valves 56 and 57 and the check valves 56a and 57a are constituted by leaf valves.

    The bottom member 44 is provided with a passage 54 that allows the piston side chamber 50 and the circulation passage R to communicate with each other, and a check valve that allows fluid to flow only from the piston side chamber 50 to the circulation passage R in the middle of the passage 54. 55 is provided.

  A restriction is provided in at least one of the circulation passage R, the connection passages 52 and 53, and the passage 54, or the passage cross section is narrowed to provide resistance to the flow of fluid so that the compression side damping valve 56 can generate a damping force. ing.

  The cylinder 42 is filled with a gas G as a working gas, and the oil storage chamber S and the circulation passage R are filled with lubricating oil O. The oil level in the oil storage chamber S is the oil storage chamber. In consideration of the fact that the gas pressure of the gas G in S and the gas pressure of the gas G in the circulation passage R do not fall below the lowermost end of the annular seal 48, there is sufficient in the circulation passage R. An amount of lubricating oil O is filled.

  A small amount of lubricating oil O is also injected into the rod-side chamber 40 and the piston-side chamber 50. The lubricating oil O injected into the rod-side chamber 40 is the cylinder when the pneumatic shock absorber performs the expansion / contraction operation for the first time. The lubricating oil O in the piston side chamber 50 is supplied before the gas G in the circulation passage R during the pressure side stroke of the pneumatic shock absorber, and is stored. This is to prevent the oil level in the chamber S from falling.

  In the pneumatic shock absorber configured as described above, the piston rod 51 is retracted from the inside of the cylinder 42, that is, the gas G enclosed in the rod side chamber 40 is provided in the piston 45 during the extension stroke of the pneumatic shock absorber. The expansion side communication passage 45b passes through the piston side chamber 50 and the expansion side damping valve 57 provided in the expansion side communication passage 45b generates an expansion side damping force.

  In addition, the piston rod 51 enters the cylinder 42, that is, in the pressure side stroke of the pneumatic shock absorber, the gas G sealed in the piston side chamber 50 passes through the pressure side communication passage 45a provided in the piston 45 and passes through the rod side chamber. The pressure side damping force is generated by the pressure side damping valve 56 provided in the pressure side communication passage 45a.

  At this time, due to the pressure increase in the piston side chamber 50, the lubricating oil O in the piston side chamber 50 flows into the circulation passage R through the passage 54 with the check valve 55.

  Then, since the circulation passage R and the oil storage chamber S are pressurized in the same manner as the piston side chamber 50, the lubricating oil O in the circulation passage R flows into the oil storage chamber S, and the pressure in the oil storage chamber S and Raise the oil level.

Due to the rise in the oil level and the pressure rise in the oil storage chamber S, the lubricating oil O passes through the connection path 52 and flows into the rod side chamber 40, and the lubricating oil O circulates in the pneumatic shock absorber. Become.
JP 2007-16880 A (Fig. 2 and paragraph numbers ~)

  In the pneumatic shock absorber configured as described above, the lubricating oil O moves back and forth between the rod side chamber 40 and the piston side chamber 50 as described above, so that the space between the outer periphery of the piston 45 and the inner periphery of the cylinder 42 is increased. Lubrication of the sliding portion and lubrication of the sliding portion between the inner periphery of the sealing member 49 provided at the upper end of the cylinder 42 and the outer periphery of the piston rod 51 are performed to facilitate the operation of the pneumatic shock absorber. Therefore, although there is no functional defect, improvement of the following problems is desired.

  First, since the circulation passage R for lubrication is provided in order to secure the lubricating oil, the number of parts is large and the structure is complicated, which is not only disadvantageous in workability and assembly, but also lubrication in the circulation passage R. Since it is necessary to inject oil, a lot of lubricating oil is required, which is disadvantageous in terms of economy.

  Second, since the piston 45 is provided with the expansion side damping valve 57, the expansion side check valve 57a, etc., the total amount of the lubricating oil flowing through the gaps between the connection path 52, the piston rod 51 and the bearing 46 is reduced to the cylinder. It is not necessarily supplied between the inner periphery of 42 and the outer periphery of the piston 45, and a part of the fuel may flow into the piston-side chamber 50 as it is through the extension-side damping valve 57 and the extension-side check valve 57 a. is there. Therefore, in order to supply a sufficient amount of lubricating oil to the outer periphery of the piston 45, it is only necessary to increase the amount of injected lubricating oil. However, in this case as well, it is disadvantageous in terms of economy.

  Therefore, the object of the present invention is to secure the lubricating oil without using the lubricating oil circulation passage, and to the sliding portion between the inner periphery of the cylinder and the outer periphery of the piston without injecting a large amount of lubricating oil. The object of the present invention is to provide a pneumatic shock absorber that can supply lubricating oil efficiently, has a simple and simple structure, and can improve workability, assembly, and economy.

    In order to achieve the above object, the means of the present invention includes a cylinder, a rod guide provided at an end of the cylinder for guiding the piston rod, and disposed on the upper surface of the rod guide and sliding on the piston rod. A main seal having an inner peripheral lip that contacts and seals between them, a piston that is movably inserted into the cylinder via the piston rod and that divides the cylinder into a rod side chamber and a piston side chamber, and In the pneumatic shock absorber having a communication passage communicating between the rod side chamber and the piston side chamber, the working gas is sealed in the cylinder, and the communication passage is provided outside the cylinder and in the middle of the communication passage. A damping force generator is provided, and the minimum amount of lubricating oil necessary for lubrication is injected into the rod side chamber.

  In the pneumatic shock absorber according to the present invention, when the pneumatic shock absorber in which the piston moves up and down in the cylinder, the lubricating oil previously injected into the rod side chamber slides between the cylinder inner peripheral surface and the piston outer peripheral surface. Since it is always supplied to the part, a certain amount of lubricating oil can be supplied to the sliding part.

  Lubricating oil is injected into the rod side chamber to the minimum necessary for lubrication, so that the amount of lubricating oil used can be reduced.

  In addition, since the circulation passage for the lubricating oil is not used, it is possible to reduce the lubricating oil as compared with the case where the lubricating oil is injected into the circulation passage.

  Similarly, the structure that does not use the circulation passage for lubricating oil is simplified, and the whole structure is simple, so that the workability, assembling property, and economic efficiency can be improved.

  In the following, an embodiment in which the valve structure of the present invention is embodied in a pneumatic shock absorber used in an automobile suspension device will be described with reference to FIG.

  As shown in FIG. 1, the basic structure of the pneumatic shock absorber 1 includes a cylinder 3, a rod guide 12 provided at an end of the cylinder 3 for guiding a piston rod 6, and an upper surface of the rod guide 12. And a main seal 13 having an inner peripheral lip 15 that is in sliding contact with the piston rod 6 to seal between them, and is movably inserted into the cylinder 3 through the piston rod 6 and the cylinder 3 A piston 5 that divides the inside into a rod side chamber 40 and a piston side chamber 50, and a communication passage 20 that communicates between the rod side chamber 40 and the piston side chamber 50, and in which the working gas is enclosed in the cylinder 3 It is.

  In the present invention, the communication path 20 is provided as a pipe line outside the cylinder 3 and a damping force generating portion V is provided in the middle of the communication path 20 so that the minimum lubrication necessary for lubrication is provided in the rod side chamber 40. Oil O is being injected.

  In this case, it is preferable to provide a piston-side seal member 7 that seals between the piston 5 and the cylinder 3 while being in sliding contact with the inner peripheral surface of the cylinder 3 on the outer peripheral portion of the piston 5.

  For the connection of the communication passage 20 to the piston side chamber 50, for example, the base valve 4 may be used as shown in FIG. 1, and the cylinder 3 as shown in FIGS. 2 (A), (B), (C). You may utilize the channel | path 20A formed in bottom BT of this. The structure of FIG. 2 (C) is a schematic representation of the structure of the base valve 4 of FIG. 1, and both are substantially the same.

  As shown in FIG. 2A, the damping force generator V may be a throttle 23 shared between the expansion side and the compression side. As shown in FIGS. 1, 2B, and 2C, the rod side chamber 40 and the piston side chamber 50 are used. A pressure-side communication passage 21 and an expansion-side communication passage 22 that communicate with each other, and an expansion-side check valve 22a and an expansion-side throttle that are provided in the expansion-side communication passage 22 and allow only a fluid flow toward the piston-side chamber 50. The pressure side check valve 21a and the pressure side throttle valve 21b, which are provided in the pressure side communication passage 21 and permit only the flow of fluid from the piston side chamber 50 toward the space 60, may be used.

  In the case of FIGS. 1 and 2C, the valve body 19 is erected on the bottom 3a or the bottom BT of the cylinder 3 to form a space P outside the valve body 19, and the lubricating oil leaks from the outer periphery of the piston 5. However, the lubricating oil accumulates in this space so that the lubricating oil does not pass through the damping force generating portion V during the expansion and contraction operation.

  The detailed structure and operational effects will be described below with reference to the drawings, but the present invention is not limited to this structure.

  A rod guide 12 for guiding the piston rod 6 is disposed at the opening end of the cylinder 3, and the main seal 13 is placed on the upper surface of the rod guide 12.

  The cylinder 3, the main seal 13, and the rod guide 12 are integrally crimped and fixed by bending the upper end of the cylinder 3 inward.

  The rod guide 12 is formed in a columnar shape having a guide hole 17 to which a bearing 12a as a bearing is attached at the center, and the inner peripheral surface of the bearing 12a is in sliding contact with the outer peripheral surface of the piston rod. A piston rod 6 is slidably supported by a bearing, and a storage recess 18 for storing lubricating oil O is formed at the center of the upper surface.

  The bearing 12a is fitted with a seal ring 12b as a seal member. An oil storage chamber S is defined by the main seal 13, the seal ring 12b and the piston rod 6, and the oil storage chamber S has a lubricating oil. O is stored in a sealed state.

  The main seal 13 includes an annular insert metal 14 and an inner peripheral lip 15 as an annular seal integrally formed on the inner peripheral side of the insert metal 14.

  The inner peripheral lip 15 is in sliding contact with the outer peripheral surface of the piston rod 6 to prevent dust from entering from the atmosphere side. Similarly, the inner lip 15 is in sliding contact with the outer peripheral surface of the piston rod 6 and is lubricated from the oil storage chamber S. The oil lip 15b prevents the oil O from leaking to the atmosphere side together with the gas G sealed in the cylinder 3.

  Further, the lubricating oil O is stored in the oil storage chamber S up to a position where the lip portion of the oil lip 15b is immersed. The lubricating oil O stored in the oil storage chamber S causes the inner peripheral lip 15 and the piston rod 6 to It is designed to prevent oil film breakage between the two.

  The piston 5 is fixedly attached to the lower end of the piston rod 6, and an outer peripheral surface is provided with an attachment recess 5a, and an O-ring as the piston-side seal member 7 is fitted into the attachment recess 5a. .

  The O-ring is designed to always maintain a state where a predetermined amount of the lubricating oil O previously injected into the rod side chamber 40 is supplied to the sliding portion between the inner peripheral surface of the cylinder 3 and the outer peripheral surface of the piston 5. In addition, when the pneumatic shock absorber 1 in which the piston 5 moves up and down in the cylinder 3 is operated, the lubricating oil O is contained in the piston side chamber 50 through the sliding contact gap between the inner peripheral surface of the cylinder 3 and the outer peripheral surface of the piston 5. It is designed to prevent leakage.

  The seal member 7 can be used without it.

  In the embodiment shown in FIG. 1, the piston 5 is not provided with a damping force generation unit, and a communication path 20 including an external pipe line is used.

  A damping valve generating base valve 4 provided at the bottom 3 a is provided in the piston side chamber 50, and one end of the communication passage 20 is communicated with the piston side chamber 50 via the base valve 4.

  A piston side seal member 7 that seals between the piston 5 and the cylinder 3 while being in sliding contact with the inner peripheral surface of the cylinder 3 is provided on the outer periphery of the piston 5, and the rod side chamber 40 has a minimum required for lubrication. The maximum amount of lubricating oil O is injected.

  The base valve 4 includes a hollow valve body 19 that rises from the bottom 3 a in the cylinder 3, a space 60 formed in the valve body 19, and a damping force generator V provided at the top of the valve body 19. One end of the communication path 20 is communicated with the space 60. However, the space part 60 is not necessarily required.

  The damping force generation part 4 is provided in the pressure side communication path 21 and the extension side communication path 22 that communicate between the piston side chamber 40 and the space part 60, and in the extension side communication path 22. An extension check valve 22a and an extension throttle 22b that allow only the flow of fluid toward the side chamber 50, and the flow of the fluid that is provided in the pressure side communication passage 21 and that flows from the piston side chamber 50 toward the space 60 are allowed. It comprises a pressure side check valve 21a and a pressure side throttle valve 21b.

  In the pneumatic shock absorber 1 configured in this manner, for example, a rod-side eye (not shown) provided at the tip of the piston rod 6 is attached to the vehicle body side, and a cylinder-side eye 37 provided at the lower end of the cylinder 3 is attached. By attaching to the axle side, it is incorporated into the suspension system of an automobile.

  Next, the operation will be described. The piston rod 6 enters the cylinder 3, that is, in the pressure side stroke of the pneumatic shock absorber 1, the gas G in the piston side chamber 50 passes through the pressure side communication passage 21 and enters the space. The pressure side damping force is generated by the pressure side throttle 21 b provided in the middle of the pressure side communication path 21 while flowing into the rod side chamber 40 via the part 60 and the communication path 20.

  Further, in the expansion stroke of the pneumatic shock absorber 1, that is, when the piston rod 6 retreats from the cylinder 3, the gas G in the rod side chamber 40 guided to the space portion 60 through the communication path 20 is expanded in the expansion side communication. While passing through the passage 22 and flowing into the piston-side chamber 50, an extension-side damping force is generated by the extension-side restrictor 22b provided in the middle of the extension-side communication passage 22.

  At this time, the piston 5 moves up and down in the cylinder 3. In the rod side chamber 40, the sliding portion between the inner peripheral surface of the cylinder 3 and the outer peripheral surface of the piston 5 is injected into the rod side chamber 40 in advance. Since a certain amount of the lubricating oil O is supplied by the lubricating oil O that has been applied, the lubricity of the sliding portion is stabilized and a smooth operation as the pneumatic shock absorber 1 is ensured.

  The lubricating oil O injected into the rod-side chamber 40 is injected into the rod-side chamber 40 by the piston-side seal member 7 that seals between the inner periphery of the cylinder 3 provided on the outer periphery of the piston 5. And leakage to the piston side chamber 50 through a sliding contact gap between the piston 5 and the outer peripheral surface of the piston 5.

  The outer periphery of the piston rod 6 and the bearing 12a and the seal ring 12b are lubricated with an oil film by the lubricating oil in the oil storage chamber S. The lubricating oil in the oil storage chamber S leaks into the rod side chamber 40 and flows out. This is prevented by the seal ring 12b.

  In the above description, even if a slight amount of lubricating oil leaks and accumulates in the piston side chamber 50 during expansion / contraction operation, the valve body 19 of the base valve V stands up. The lubricating oil O does not pass through the damping force generating portion V during the expansion / contraction operation, and a desired damping force resulting from the passage of only the working gas can be obtained simply by accumulating in the gap P which is the lower outer periphery of the lower part 19. .

  However, as described above, since the leakage of the lubricating oil O can be prevented by the piston-side seal member 7, the lubricating oil O does not flow in a large amount in the communication path 20, and there is almost no risk that the lubricating oil will decrease. Therefore, the passage 20A can be directly opened in the piston side chamber 50 as shown in FIGS. 2A and 2B, and the damping force generator 4 can be incorporated in the passage 20A.

  The communication path 20 uses a pipe provided outside the cylinder 3, but an outer cylinder is provided outside the cylinder 3 and concentric with the cylinder 3, and the communication path is separated between the cylinder 3 and the outer cylinder. You may make it.

  As described above in detail, in the pneumatic shock absorber 1 of the present embodiment, the lubrication previously injected into the rod side chamber 40 during the operation of the pneumatic shock absorber 1 in which the piston 5 moves up and down in the cylinder 3. The oil O is always supplied to the sliding portion between the inner peripheral surface of the cylinder 3 and the outer peripheral surface of the piston 5, and this supply state is maintained by the O-ring 7 provided on the piston 3. A certain amount of lubricating oil O can be supplied.

  Therefore, the lubricity of the sliding portion can be stabilized and a smooth operation as the pneumatic shock absorber 1 can be ensured.

  Further, since the piston 5 is provided with the piston-side seal member 7 and the sliding portion with the inner peripheral surface of the cylinder 3 is sealed, it is possible to prevent the lubricating oil O from leaking to the piston-side chamber 50 through the sliding portion.

  Further, since the lubricating oil O is not circulated between the piston side chamber 50 and the rod side chamber 40 through the passage in the piston, there is no need to provide a circulation path or a special circulation structure in the piston, and the pneumatic shock absorber 1 itself Can be manufactured inexpensively as a simple structure.

  Further, since the damping force generating portion V is provided in the base valve 4 standing in the piston side chamber 50 or the bottom BT of the cylinder 3, the whole can be made more compact than being provided independently outside.

  However, it goes without saying that the damping force generating portion V can be used even if it is provided outside the cylinder 3 independently.

It is sectional drawing of the pneumatic shock absorber which shows one embodiment of this invention. (A), (B), and (C) are schematic sectional views of a pneumatic shock absorber according to another embodiment. It is sectional drawing of the pneumatic shock absorber which shows a conventional structure.

Explanation of symbols

1 Pneumatic shock absorber 3 Cylinder 3c Bottom 4 Base valve 5 Piston 6 Piston rod 7 O-ring (Piston side seal member)
12 Rod guide 12b Seal ring (seal member)
13 Main seal (sealing member)
15 inner peripheral lip 19 valve body 20 communication path 20A path 21 pressure side communication path 21a pressure side check valve 21b pressure side throttle 22 expansion side communication path 22a expansion side check valve 22b expansion side throttle 40 rod side chamber 50 piston side chamber 60 space O lubrication Oil S Oil storage chamber G Gas (working gas)
V Damping force generator

Claims (7)

A cylinder 3, a rod guide 12 provided at the end of the cylinder 3 for guiding the piston rod 6, and an upper surface of the rod guide 12 and being in sliding contact with the piston rod 6 to seal between them. A main seal 13 having an inner peripheral lip 15, a piston 5 that is movably inserted into the cylinder 3 through the piston rod 6 and divides the cylinder 3 into a rod side chamber 40 and a piston side chamber 50, and the above In the pneumatic shock absorber provided with the communication passage 20 that communicates between the rod side chamber 40 and the piston side chamber 50, and the working gas is sealed in the cylinder 3, the communication passage 20 is provided outside the cylinder 3. A damping force generating portion V is provided in the middle of the communication passage 20, and a minimum amount of lubricating oil O necessary for lubrication is injected into the rod side chamber 40. Pneumatic shock absorber to. 2. The pneumatic shock absorber according to claim 1, wherein a piston-side seal member 7 that seals between the piston 5 and the cylinder 3 while being in sliding contact with the inner peripheral surface of the cylinder 3 is provided on the outer peripheral portion of the piston 5. The base valve 4 provided with a damping force generation part V is provided at the bottom 3a in the piston side chamber 50, and one end of the communication passage 20 is communicated with the piston side chamber 50 through the base valve 4. 2. The pneumatic shock absorber according to 2. The pneumatic buffer according to claim 1 or 2, wherein a passage 20A for connecting the communication passage 20 to the piston side chamber 50 is formed in the bottom BT of the cylinder 3, and a damping force generating portion V is provided in the middle of the passage 20A. vessel. 5. The pneumatic shock absorber according to claim 1, 2, 3 or 4, wherein the damping force generating part V comprises a compression side common throttle 23 extending on the extension side. The damping force generation part V is provided in the extension side communication path 22 and the pressure side communication path 21 and the extension side communication path 22 that communicate between the rod side chamber 40 and the piston side chamber 50, and the flow of fluid toward the piston side chamber 50 An extension check valve 22a and an extension restrictor 22b that allow only pressure, and a pressure check valve 21a and a pressure side that are provided in the pressure side communication passage 21 and allow only the flow of fluid from the piston side chamber 50 toward the space 60. The pneumatic shock absorber according to claim 1, 2, 3, or 4, characterized by comprising a throttle valve 21b. A seal member (12b) is provided at a sliding portion of the rod guide (12) with the piston rod (6), and an oil storage chamber (S) for storing lubricating oil is defined on the upper surface side of the rod guide (12). The pneumatic shock absorber according to 3, 4, 5 or 6.

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