JP4883703B2 - Double cylinder type shock absorber - Google Patents

Description

  The present invention relates to a double cylinder type shock absorber.

  In a conventional double cylinder type shock absorber, a cylinder, a piston that is slidably inserted into the cylinder and divides the inside of the cylinder into two pressure chambers, a piston rod having one end connected to the piston, and a cylinder are provided. A covering outer cylinder, a reservoir formed between the cylinder and the outer cylinder, a bearing member provided at the end of the cylinder to support the piston rod, and laminated between the outer cylinder and the piston rod. And a seal member that seals the vehicle, and is interposed between a vibration suppression target, for example, a vehicle body and an axle of the vehicle, to suppress vehicle body vibration.

In the case of such a double cylinder type shock absorber, the working fluid passes between the piston rod and the bearing member and flows into the space between the bearing member and the seal member, and the space is accumulated to tighten the seal member. Therefore, the piston rod and the bearing member are not completely sealed, and a passage that connects the space and the reservoir is provided to flow into the space. The working fluid is returned to the reservoir (see, for example, Patent Document 1).
JP 09-317914 A (FIG. 3)

  Here, the multi-cylinder shock absorber generally uses oil as the working fluid. However, when oil is used as the working fluid, the oil acts as a pressure due to the influence of gas contained in the oil. It has the property of being compressed and has a tendency to delay the damping force generation response due to its defoaming ability being limited. To improve this, it may be possible to set the gas pressure in the reservoir to a large value. However, if this is done, the tightening force of the seal member will increase and the sliding resistance of the piston rod will increase, preventing smooth expansion and contraction. A new problem arises.

  In order to improve the responsiveness of the damping force generation in the double-cylinder shock absorber while eliminating these problems, it is conceivable to use an aqueous fluid for the working fluid to have a low compressibility and an excellent defoaming property. When the fluid is used as the working fluid, since the water-based fluid has poor lubricity, a means for lubricating between the seal member and the piston rod is required.

  Therefore, when an aqueous fluid is employed as the working fluid, a lubricating oil having a specific gravity smaller than that of the aqueous fluid is added to the aqueous fluid, and a space between the seal member and the bearing member disposed on the upper side of the double cylinder type shock absorber. It is possible to adopt a method of lubricating the gap between the seal member and the piston rod by retaining the lubricating oil.

  However, as described above, in the case of the double cylinder type shock absorber, the configuration is such that the working fluid that passes between the piston rod and the bearing member and flows into the space between the bearing member and the seal member is returned to the reservoir. As a result, the lubricating oil staying in the space is pushed away to the reservoir by repeated expansion and contraction operations.

  A gas that is lighter than the lubricating oil is sealed in the reservoir, and when the lubricating oil is pushed away into the reservoir, it stays between the working fluid and the gas and returns directly from the reservoir to the space. In addition, the working fluid is supplied from the reservoir into the cylinder during the expansion stroke of the double cylinder type shock absorber, but there is almost no opportunity for the lubricating oil staying between the working fluid and the gas to be supplied into the cylinder. Therefore, the lubricating oil does not return to the space even after passing through the cylinder.

Therefore, in the structure of the conventional double cylinder type shock absorber, the lubricating oil staying in the space between the seal member and the bearing member is not returned to the space once pushed into the reservoir, but the seal member and the piston rod since it is impossible to lubricate between the simply only the addition of the lubricating oil it would not be able to adopt a water-based fluid to the working fluid.

  Therefore, the present invention was devised in order to improve the above-described problems, and an object of the present invention is to provide a double cylinder type shock absorber capable of selecting an aqueous fluid as a working fluid. is there.

In order to achieve the above object , a multi-cylinder shock absorber according to the problem solving means of the present invention includes a cylinder, a piston that is slidably inserted into the cylinder and defines two pressure chambers in the cylinder, and a piston. A piston rod to be connected, an outer cylinder that covers the cylinder, a reservoir formed between the cylinder and the outer cylinder, a bearing member that is provided at the end of the cylinder and supports the piston rod, and is stacked on the bearing member And a seal member that seals between the outer cylinder and the piston rod, and the working fluid that has passed between the inner periphery of the bearing member and the outer periphery of the piston rod is transferred to the reservoir through the space between the bearing member and the seal member. in a so as to reflux twin-tube type shock absorber, between the working fluid and lubricant bearing member and the seal member to be added to the working fluid by reducing the specific gravity than the water-based fluid with an aqueous fluid By staying lubrication between the seal member and the piston rod, characterized in that the air chamber is partitioned by the diaphragm in the reservoir.

  According to the double cylinder type shock absorber of the present invention, the air chamber in the reservoir is partitioned by the diaphragm, and even if the lubricating oil flows out to the reservoir, the lubricating oil has a lower specific gravity than the water-based fluid, so that the sealing member is sealed from the reservoir. Between the bearing member and the bearing member. Therefore, the lubricating oil between the seal member and the bearing member is not exhausted, and the sliding portion between the seal member and the piston rod can be continuously lubricated.

  That is, in this double cylinder type shock absorber, since the lubricating oil can be retained between the seal member and the bearing member, the sliding portion between the seal member and the piston rod can be continuously lubricated. This makes it possible to select an aqueous fluid as the working fluid.

  In addition, since an aqueous fluid that is smaller in compressibility and superior in defoaming property than oil can be used as a working fluid, the damping force generation responsiveness in the double cylinder type shock absorber is improved and aeration is also generated. It becomes possible to suppress.

  The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a longitudinal sectional view of a shock absorber according to an embodiment. FIG. 2 is a partially enlarged longitudinal sectional view of a shock absorber according to another embodiment.

  As shown in FIG. 1, a multi-cylinder shock absorber D according to an embodiment includes a cylinder 1 and a piston that is slidably inserted into the cylinder 1 and divides one chamber R1 and the other chamber R2 into the cylinder 1. 2, a piston rod 3 connected to the piston 2, an outer cylinder 4 covering the cylinder 1, a reservoir R formed between the cylinder 1 and the outer cylinder 4, and a piston rod provided at the end of the cylinder 1 3, a seal member 6 that is laminated on the bearing member 5 and seals between the outer cylinder 4 and the piston rod 3, and a diaphragm 7 that partitions the air chamber G in the reservoir R. The working fluid is a glycol aqueous solution (hereinafter referred to as “working water”) which is an aqueous fluid, and is filled in the cylinder 1 together with a small amount of lubricating oil O.

  Hereinafter, each member will be described in detail. As described above, the piston 2 divides the inside of the cylinder 1 filled with the aqueous glycol solution into two pressure chambers R1 and R2, and further from the one chamber R1 to the other. A port 2a that allows only the flow of working water toward the chamber R2 and a port 2b that allows only the flow of working water from the other chamber R2 to the one chamber R1 are configured. A leaf valve 8 that opens and closes the outlet end of the port 2b is stacked above the piston 2 in FIG. 1, and a leaf valve 9 that opens and closes the outlet end of the port 2a is stacked below the piston 2 in FIG. The leaf valves 8 and 9 are fixed together with the piston 2 to the tip 3 a of the piston rod 3 by a piston nut 10.

  Further, the lower end of the cylinder 1 is closed by a bottom member 11. The bottom member 11 has a port 11 a that allows only the flow of working water from the other chamber R 2 to the reservoir R, and the reservoir R to the other chamber R 2. And a port 11b that permits only the flow of working water to the outside. A check valve 12 that opens and closes the outlet end of the port 11b is stacked above the bottom member 11 in FIG. 1, and a leaf valve 13 that opens and closes the outlet end of the port 11a is positioned below the bottom member 11 in FIG. The check valve 12 and the leaf valve 13 are fixed to the bottom member 11 with bolts 14 and nuts 15 penetrating the bottom member 11. The bottom member 11 is sandwiched between the cap C fixed to the lower end of the outer cylinder 4 and the cylinder 1 and integrated with the cylinder 1 and the outer cylinder 4.

  In the double cylinder type shock absorber D, when the piston 2 moves upward in FIG. 1 with respect to the cylinder 1 and the double cylinder type shock absorber D extends, the inside of the one chamber R1 is provided via the port 2a. A resistance is given to the flow of the working water moving into the other chamber R2 by the leaf valve 9 to generate the extension side damping force. During this extension stroke, there is a shortage of working water for the volume in which the piston rod 3 retreats from the cylinder 1, so that the shortage of working water is supplied from the reservoir R into the other chamber R2 via the port 11b.

  On the other hand, when the piston 2 moves downward in FIG. 1 with respect to the cylinder 1 and the double-tube shock absorber D contracts, the working water moves from the other chamber R2 into the one chamber R1 via the port 2b. At the same time, the working water corresponding to the volume of the piston rod 3 entering the cylinder 1 flows out to the reservoir R through the port 11a. And the double cylinder type | mold buffer D gives resistance to the flow of the working water mentioned above by the leaf valve 8 and the leaf valve 13 at the time of a compression stroke, and generate | occur | produces the compression side damping force.

  In the above description, the ports 2a, 2b, 11a, and 11b are one-way ports. However, the ports 2a, 2b, 11a, and 11b may be two-way ports. In addition to the leaf valves 8, 9, and 13 described above, an orifice or a poppet valve may be used.

  In the case of this double cylinder type shock absorber D, an aqueous fluid is adopted as a working fluid, and the aqueous fluid is less compressible than oil, so that the responsiveness of generating damping force is improved compared to oil. Can be made. The water-based fluid is a concept including not only water alone but also an aqueous solution in which an additive such as glycols is added to water as in the present embodiment, and the double-cylinder shock absorber D is a metal material. When comprised, you may make it use what added the antirust agent to water.

Furthermore, in the case of this embodiment, as described above, since the aqueous glycol solution is used as the aqueous fluid, the freezing point can be lowered as compared with water alone, so that the function as a buffer is maintained even in cold regions. Returning, the piston 2 is connected to the piston rod 3 as described above, and this piston rod 3 is an inner part of the annular bearing member 5 fitted to the upper end side of the cylinder 1 in FIG. It is inserted into a bearing 16 held around the circumference and protrudes out of the cylinder 1.

And the bearing member 5 is provided in the upper end in FIG. 1 which becomes the seal member side end of the flange part 5a which fits the outer cylinder 4 and obstruct | occludes the upper end of the reservoir | reserver R, and is the seal member 6 A recess 5b that forms a lubricant chamber J in which the lubricant O stays between, a protrusion 5c that hangs down from the lower end in FIG. The bearing 16 is held on the inner periphery of the piston rod insertion hole 5f that is provided and fitted to the cylinder 1 and that communicates with the recess 5b from the lower end of the fitting portion 5d.

  The bearing member 5 has a fitting portion 5d having a smaller diameter than the convex portion 5c is fitted to the upper end of the cylinder 1, and the outer periphery of the flange portion 5a is fitted to the inner periphery of the outer cylinder 4, so that the annular portion of the flange portion 5a The reservoir-side end 5e closes the upper end of the reservoir R.

  Further, the reservoir-side end 5e of the flange portion 5a is a tapered surface inclined so as to be recessed on the inner peripheral side, and the bottom of the recess 5b is disposed on the upper side in the drawing from the upper end of the reservoir-side end 5e. Is set to

  Further, the bearing member 5 is formed with a reflux passage 17 penetrating upward from the side of the convex portion 5c to the bottom portion of the concave portion 5b, and the reservoir R, the lubricating oil chamber J, and the like. Is communicated.

  A baffle plate 18 is accommodated in the lubricating oil chamber J described above, and the baffle plate 18 is formed from a cylindrical portion 18a fitted to the inner periphery of the recess 5c, and an upper end of the cylindrical portion 18a in FIG. An annular flange 18b extending to the inner peripheral side is provided, and the inner periphery of the flange 18b faces the outer periphery of the piston rod 3 via an annular gap. Therefore, the lubricating oil O staying on the upper side of the baffle plate 18 must pass through an annular gap that is difficult to pass in order to move to the lower side of the baffle plate 18. The outflow of the lubricating oil O from the lubricating oil chamber J is suppressed.

  Further, a seal member 6 is laminated above the bearing member 5 in FIG. 1, and the seal member 6 is sandwiched between the outer cylinder 4 and the cylinder 1 together with the bearing member 5 by crimping the upper end of the outer cylinder 4. The cylinder 1 and the outer cylinder 4 are integrated.

  The seal member 6 includes an annular plate-shaped insert metal 6a, an inner peripheral seal 6b that is held on the inner periphery of the insert metal 6a and slidably contacts the outer periphery of the piston rod 3, and an outer peripheral side and an outer side of the insert metal 6a. The inner peripheral seal 6b faces the lubricating oil chamber J. The inner peripheral seal 6b faces the lubricating oil chamber J, and the inner oil is retained by the lubricating oil O retained in the lubricating oil chamber J. The sliding portions on the outer periphery of the peripheral seal 6b and the piston rod 3 are lubricated.

  The above-described baffle plate 18 is considered so as not to interfere with the inner peripheral seal 6b, and the sliding oil is retained by the lubricating oil O that stays above the baffle plate 18 where the outflow is suppressed by the baffle plate 18. Since the moving part is lubricated, the sliding part can be reliably lubricated.

  In turn, a cylindrical diaphragm 7 is accommodated between the outer cylinder 4 and the cylinder 1, and an air chamber G set at a predetermined gas pressure is defined between the outer cylinder 4 and the reservoir R. Is divided into an air chamber G and a liquid chamber L. The upper and lower ends of the diaphragm 7 are pressed against the inner peripheral side of the outer cylinder 4 by the rings 19 and 20, and the air chamber G can be maintained in an airtight state. Specifically, both the rings 19 and 20 are provided with recesses 19a and 20a on the outer peripheral side and are formed in a U-shaped cross section, and the thick portions 7a and 7b at the upper and lower ends of the diaphragm 7 are accommodated in the recesses 19a and 20a, respectively. The thick portions 7a and 7b are brought into pressure contact with the inner peripheral side of the outer cylinder 4 so that the air chamber G is in an airtight state.

  A cylinder 21 is inserted between the diaphragm 7 and the cylinder 1 to prevent the diaphragm 7 from contacting the cylinder 1 over the entire circumference and to form a gap between the cylinder 1 and the cylinder 21. The cylinder 21 includes a bent portion 21a formed by being bent at the upper end on the inner peripheral side, holes 21b and 21c communicating with the inside and the outside, and a notch 21d provided in a part of the bent portion 21a. The bent portion 21 a described above is sandwiched between the lower end in FIG. 1 of the convex portion 5 c of the bearing member 5 and the upper end of the cylinder 1 and is fixed to the cylinder 1.

  Further, the inner diameter of the cylinder 21 is set larger than the outer diameter of the cylinder 1, and an annular gap 22 is formed between the cylinder 21 and the cylinder 21. The diaphragm 7 is not closed over the circumference, and the lower side and the upper side of the diaphragm 7 of the liquid chamber L are always in communication with each other through the gap 22 and the notch 21d.

  The diaphragm holding member is a member provided to prevent the diaphragm 7 from contacting the cylinder 1 over the entire circumference so that the lower side and the upper side of the liquid chamber L are always in communication with each other. Therefore, as long as the function is fulfilled, the shape may be other than the cylinder 21.

  Further, when the diaphragm 7 is not always closed by the diaphragm 7 over the entire circumference between the outer cylinder 4 and the cylinder 1, the lower side and the upper side of the diaphragm 7 of the liquid chamber L are always in a communication state. Alternatively, a pipe longer than the axial length of the diaphragm 7 may be accommodated in the reservoir R so that the lower side and the upper side of the diaphragm 7 of the liquid chamber L are always communicated with each other through the pipe.

  Returning, the inner periphery of the diaphragm 7 is in contact with the outer periphery of the cylinder 21 as the above-described diaphragm restraining member due to the pressure in the air chamber G, and the inner periphery of the rings 19 and 20 is also in contact with the outer periphery of the cylinder 21. The rings 19 and 20 are pressed against the outer cylinder 4 side by the cylinder 21 in contact therewith. That is, in this case, the cylinder 21 also plays a role of lining the rings 19 and 20 to enhance the sealing property of the air chamber G. However, if the sealing property of the air chamber G can be sufficiently secured, There is no need to bring the inner circumference of 20 into contact with the outer circumference of the cylinder 21.

  As described above, when the diaphragm 7 is installed in the reservoir R, the middle part of the diaphragm 7 abuts on the outer periphery of the cylinder 21 as described above, and the space S1 formed by the ring 19, the diaphragm 7 and the cylinder 21 is formed. If the space S2 formed by the ring 19, the diaphragm 7, and the cylinder 21 is sealed, the reservoir R cannot compensate for the volume by which the piston rod 3 advances and retreats to the cylinder 1. Therefore, the cylinder 21 The spaces S1 and S2 are communicated with the gap 22 through the holes 21b and 21c.

  Further, in the ring 19 disposed on the upper side, as shown in FIG. 2, a groove 19b penetrating in the vertical direction is provided, and the space S1 and the upper side of the liquid chamber L are connected via the groove 19b. It is possible to communicate and prevent the space S1 from being sealed. Although the groove 19b has been described above, a hole penetrating the ring 19 in the vertical direction may be provided instead.

  And the inside of the cylinder 1 and the liquid chamber L of the double cylinder type | mold buffer D comprised in this way are filled with the working water mentioned above, and the sliding part of the sealing member 6 and the piston rod 3 is filled in this working water. Lubricating oil O for lubricating is added. The lubricating oil O has a specific gravity smaller than that of the working water, floats above the working water in the one chamber R1 of the cylinder 1 and stays in the lubricating oil chamber J.

  In addition, it is possible to lubricate the space between the outer periphery of the piston rod 3 and the inner periphery of the bearing 16 by retaining the lubricating oil O also above the one chamber R1. However, in the case where only the lubrication of the sliding portion between the seal member 6 and the piston rod 3 which is the main object of the present invention is considered, lubrication is performed in the one chamber R1. The oil O may not be retained.

  In this manner, the sliding portion can be lubricated by retaining the lubricating oil O between the bearing member 5 and the seal member 6 facing the sliding portion of the inner peripheral seal 6 b of the seal member 6 and the piston rod 3. However, when the double-tube shock absorber D extends, the pressure in the one chamber R1 rises, and the working water in the one chamber R1 flows between the outer periphery of the piston rod 3 and the inner periphery of the bearing 16. It flows into the lubricating oil chamber J through a slight gap.

  Then, the working water flowing into the lubricating oil chamber J is retained in the lubricating oil chamber J by the working water newly flowing into the lubricating oil chamber J as the double cylinder type shock absorber D repeats expansion. Then, the lubricating oil O is entrained and pushed out through the reflux passage 17 to the liquid chamber L of the reservoir R.

  Then, as the double cylinder type shock absorber D repeats expansion and contraction, the working water moves from the one chamber R1 to the other chamber R2 of the cylinder 1 via the lubricating oil chamber J and the reservoir R, and finally, On the other hand, returning to the chamber R1, the inside of the double cylinder type shock absorber D is refluxed.

  Therefore, in this double cylinder type shock absorber D, the working water flowing between the seal member 6 and the bearing member 5 through the slight gap between the outer periphery of the piston rod 3 and the inner periphery of the bearing 16 enters the reservoir R. Since the pressure is not accumulated between the seal member 6 and the bearing member 5, the inner peripheral seal 6b of the seal member 6 is not excessively pressed against the piston rod 3, and the sliding property of the piston rod 3 is improved. 6 and the bearing member 5 does not deteriorate the accumulated pressure.

  In this way, pressure accumulation between the seal member 6 and the bearing member 5 is avoided, but the lubricating oil chamber J is caused by the return of the working water flowing between the seal member 6 and the bearing member 5 and returning to the reservoir R. The lubricating oil O staying inside gradually flows out to the reservoir R.

  However, in this double cylinder type shock absorber D, the air chamber G in the reservoir R is partitioned by the diaphragm 7, and even if the lubricating oil O flows out to the reservoir R, the lubricating oil O is more specific than the working water. Therefore, it can be stored above the reservoir R and eventually return to the inside of the lubricating oil chamber J installed between the seal member 6 and the bearing member 5 by flowing backward through the reflux passage 17. The lubricating oil O in the lubricating oil chamber J is not exhausted, and the sliding portion between the seal member 6 and the piston rod 3 can be continuously lubricated. Note that. A plurality of the reflux passages 17 may be provided in order to make the return of the lubricating oil O to the lubricating oil chamber J smoother.

  That is, in this double cylinder type shock absorber D, since the lubricating oil O can be retained between the seal member 6 and the bearing member 5, the sliding portion between the seal member 6 and the piston rod 3 is continued. Therefore, it is possible to select the aqueous fluid as the working fluid.

  And according to this double cylinder type shock absorber D, since compressibility is small compared with oil and an aqueous fluid excellent in defoaming property can be used as a working fluid, damping force generation responsiveness improves, It is also possible to suppress the occurrence of aeration.

  Further, in this double cylinder type shock absorber D, the diaphragm 7 does not block the gap between the cylinder 1 and the outer cylinder 4 over the entire circumference. The pressure between the member 6 and the bearing member 5 is accumulated, and the tightening force of the inner peripheral seal 6b of the seal member 6 does not become excessive and the slidability of the piston rod 3 is not deteriorated.

Also, when the diaphragm 7 by the cylindrical body 21 serving as the diaphragm pressing member together with is prevented from contacting the cylinder 1 all around, an annular gap 22 is formed by the cylindrical body 21 between the cylinder 1 Even when the lubricating oil O is pushed down from the diaphragm 7 in the reservoir R, the lubricating oil O quickly returns between the seal member 6 and the bearing member 5 through the annular gap 22. Therefore, it can be avoided that the lubricating oil O staying between the seal member 6 and the bearing member 5 is insufficient, and the sliding portion between the seal member 6 and the piston rod 3 can be reliably lubricated.

  When the diaphragm 7 divides the air chamber between the cylinder 1 and the diaphragm 7 and the outer cylinder 4, a diaphragm suppressing member is interposed between the diaphragm 7 and the outer cylinder 4, and the diaphragm suppresses the entire circumference by the diaphragm suppressing member. If an annular gap is formed between the outer cylinder 4 and the outer cylinder 4 while preventing contact with the outer cylinder 4, the diaphragm 7 is similar to the air chamber G defined between the outer cylinder 4 and the diaphragm 7. Since the lubricating oil O can quickly return to between the seal member 6 and the bearing member 5 through the annular gap, the sliding portion between the seal member 6 and the piston rod 3 can be reliably lubricated.

  Further, since the lower end of the lubricating oil chamber J is disposed above the upper end of the reservoir R, the lubricating oil O that has flowed into the reservoir R fails to return to the lubricating oil chamber J and stays above the reservoir R. Can be suppressed.

  Further, the reservoir side end portion 5e of the flange portion 5a of the bearing member 5 is tapered so that the inner peripheral side is recessed, and the reflux passage 17 communicates with the lubricating oil chamber J upward from the reservoir R. , It is possible to further suppress the lubricant O flowing into the reservoir R from returning to the lubricant chamber J and staying above the reservoir R, and the lack of the lubricant O between the seal member 6 and the bearing member 5 can be prevented. There is no invitation.

  Furthermore, in the present embodiment, the baffle plate 18 is accommodated in the lubricating oil chamber J described above, and the baffle plate 18 suppresses the outflow of the lubricating oil O from the lubricating oil chamber J. Therefore, even if the double cylinder type shock absorber D continues to expand and contract, the working water is constantly pushed into the lubricating oil chamber J, and it is difficult for the lubricating oil O to return from the reservoir R to the lubricating oil chamber J. Since the lubricating oil O sufficient to lubricate the sliding portion of the seal member 6 and the piston rod 3 can be secured above the baffle plate 18, the continuous operation of the multi-cylinder shock absorber D is ensured and the multi-cylinder The reliability and practicality of the mold buffer D can be improved.

  That is, the double-tube shock absorber D is optimal as a vehicle shock absorber that is frequently and continuously forced to extend and contract, specifically, between a vehicle body and an axle. Become.

  When the space S1 formed by the ring 19, the diaphragm 7 and the cylinder 21 is communicated upward from the ring 19 of the reservoir R through a groove 19b penetrating the ring 19 in the vertical direction, as shown in FIG. Thus, the return of the lubricating oil O that has entered the space S1 to the lubricating oil chamber J can be promptly performed.

  In this embodiment, the bearing member 5 is provided with a recess 5b and the inside of the recess 5b serves as a lubricating oil chamber J. However, the seal member 6 and the piston rod are interposed between the seal member 6 and the bearing member 5. You may make it provide the clearance gap which retains the quantity of lubricating oil O of the grade which can lubricate the 3 sliding part. However, when the recess 5b is provided in the bearing member 5 to form the lubricating oil chamber J, the lubricating oil O is efficiently retained around the sliding portion of the seal member 6 and the piston rod 3 even if the lubricating oil O is small. The sliding portion can be reliably lubricated with a small amount of lubricating oil.

  This is the end of the description of the embodiment of the present invention, but the scope of the present invention is of course not limited to the details shown or described.

It is a longitudinal cross-sectional view of the double cylinder type shock absorber in one embodiment. It is a partially expanded longitudinal cross-sectional view of the double cylinder type shock absorber in one modified example of the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston 2a, 2b, 11a, 11b Port 3 Piston rod 3a End of piston rod 4 Outer cylinder 5 Bearing member 5a Flange part 5b in bearing member Concave part 5c in bearing member Convex part 5d in bearing member Fitting part in bearing member 5e Reservoir side end portion 5f in the flange portion of the bearing member 6 Piston rod insertion hole 6 in the bearing member 6 Seal member 6a Insert metal 6b Inner circumference seal 6c Outer seal 7 Diaphragm 7a, 7b Thick parts 8, 9, 13 in the diaphragm Leaf valve 10 Piston nut 11 Bottom member 12 Check valve 14 Bolt 15 Nut 16 Bearing 17 Recirculation passage 18 Baffle plate 18a Cylinder portion 18b in the baffle plate Gutter 19, 20 Ring 19a, 20a in the baffle plate Recessed portion 19b in the ring Hole 21 in the cylinder 21a serving as a diaphragm restraining member 21b, 21c in the cylinder 21d in the cylinder 21d in the cylinder 22 notch 22 in the cylinder annular cap C cap D double cylinder buffer G air chamber J in the reservoir J lubricant chamber L liquid chamber in the reservoir O Lubricating oil S1, S2 Space R1 One chamber R2 as pressure chamber R2 Other chamber R as pressure chamber Reservoir

Claims (8)

A cylinder, a piston that is slidably inserted into the cylinder and defines two pressure chambers in the cylinder, a piston rod connected to the piston, an outer cylinder that covers the cylinder, and between the cylinder and the outer cylinder A reservoir that is formed, a bearing member that is provided at the cylinder end and pivotally supports the piston rod, and a seal member that is stacked on the bearing member and seals between the outer cylinder and the piston rod. In a multi-cylinder shock absorber that causes a working fluid that has passed between the circumference and the outer circumference of the piston rod to flow back to the reservoir via a bearing member and a seal member, the working fluid is an aqueous fluid and the aqueous fluid more lubricant is added during operation to reduce the specific gravity fluid lubricates between the allowed and the seal member and the piston rod remaining between the bearing member and the seal member, the reservoir Twin-tube type shock absorber is characterized in that partitions the chamber with the diaphragm. 2. The double cylinder type shock absorber according to claim 1, wherein the diaphragm is set so as not to block the gap between the cylinder and the outer cylinder over the entire circumference. Diaphragm is cylindrical and forms an air chamber between the outer cylinder and prevents diaphragm from contacting the cylinder between the cylinder and the diaphragm, and forms an annular gap between the cylinder and the diaphragm. The double cylinder type shock absorber according to claim 2, wherein a member is provided. The diaphragm is cylindrical and defines an air chamber between the cylinder and prevents the diaphragm from contacting the outer cylinder and forms an annular gap between the outer cylinder and the outer cylinder. The double cylinder type shock absorber according to claim 2, further comprising a diaphragm holding member. 2. A lubricating oil chamber for retaining lubricating oil is formed between the seal member and the bearing member, and the working fluid is recirculated to the reservoir through a recirculation passage communicating the lubricating oil chamber and the reservoir. To 4. The double cylinder type shock absorber according to any one of 4 to 4. 6. The double cylinder type shock absorber according to claim 5, wherein the lubricating oil chamber is disposed such that a lower end thereof is above an upper end of the reservoir. The bearing member is suspended from a flange portion that fits into the outer cylinder and closes the upper end of the reservoir, a recess that is provided at the seal member side end of the flange portion to form a lubricating oil chamber, and a cylinder side end of the flange portion. And a fitting portion that is provided at the cylinder side end of the convex portion and fits into the cylinder, and the reservoir side end portion of the flange portion is a tapered surface that is inclined so that the inner peripheral side is recessed. The multi-cylinder shock absorber according to claim 5 or 6, wherein the passage is formed so as to communicate with the concave portion from the side of the convex portion toward the upper side. The double cylinder type shock absorber according to any one of claims 5 to 7, wherein a baffle plate for suppressing outflow of the lubricating oil to the reservoir is provided in the lubricating oil chamber.

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