JP2014095454A - Shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shock absorber which is compact, lightweight, and inexpensive.SOLUTION: A shock absorber D including a cylinder 1, a piston 2 inserted slidably into the cylinder 1 to partition the inside of the cylinder into an extension-side chamber R and a compression-side chamber R2 each filled with a liquid, and a rod 3 inserted movably into the cylinder 1 to be connected to the piston 2 is characterized in that a reservoir R is provided in the rod 3 and linked to the compression-side chamber R2. The shock absorber D which is thus configured need not be provided with the reservoir R at an outer periphery of the cylinder 1 since the reservoir R is provided in the rod 3 and never sacrifices a stroke length since the reservoir R is arranged in parallel with the extension-side chamber R1 and compression-side chamber R2.

Description

  The present invention relates to an improved shock absorber.

  Generally, in a shock absorber, a cylinder, a piston that is slidably inserted into the cylinder and is divided into an extension side chamber and a pressure side chamber filled with hydraulic oil, and one end of the piston are connected to the piston. It comprises a rod and suppresses the vibration of the vibration control target.

  Also, compared to the double rod type with rods on both sides of the piston, the single rod type with rods on only one side of the piston is easier to secure the stroke length, so it is not possible to secure a large mounting space. In many cases, a so-called single rod type structure is adopted as the structure of the shock absorber.

  In such a single rod type shock absorber, when the piston moves in the axial direction with respect to the cylinder, the rod enters and exits into the cylinder, and the volume of the rod that enters and exits into the cylinder increases the extension side chamber in the cylinder. As a result, the total volume of the pressure side chamber changes and the amount of oil in the cylinder becomes excessive or insufficient.

  Therefore, the structure of the shock absorber is compensated by, for example, providing an annular reservoir filled with gas and hydraulic oil between the cylinder and the outer cylinder covering the cylinder, and supplying and discharging excess and deficient liquid from the reservoir. A so-called double cylinder type, or a free piston is provided in the cylinder to form an air chamber next to the pressure side chamber, and the expansion side chamber when the rod enters and exits the cylinder by expansion and contraction of the elastic gas volume The so-called single cylinder type that absorbs the total volume change of the compression side chamber is adopted, but when the single cylinder type structure is adopted, the stroke length is secured and a large damping force is obtained. In order to output, there is a restriction that the inside of the air chamber must be at a high pressure, so there is a case where a double cylinder type is desired (for example, refer to Patent Document 1).

JP 2011-174501 A

  The double cylinder type shock absorber as described above is advantageous in that it is easy to ensure the stroke length and can exert a large damping force even during the compression stroke, but on the other hand, there is an outer shell on the outer periphery of the cylinder. Since the reservoir is formed between the cylinder and the cylinder, the outer diameter of the shock absorber is increased.

  In particular, if the object to be damped is an extremely heavy object such as a building, the rod diameter must be increased from the viewpoint of strength, and the cylinder diameter is also increased due to the large amount of oil exchanged between the reservoir and the cylinder. On the other hand, since the space volume provided between the outer shell and the cylinder has to be increased, the outer shell diameter is increased, resulting in a very large outer diameter of the shock absorber. Increases the weight and costs.

  Accordingly, the present invention has been made to improve the above-described points, and an object of the present invention is to provide a shock absorber that is small, light, and inexpensive.

  The problem-solving means of the present invention includes a cylinder, a piston that is slidably inserted into the cylinder and divides the cylinder into an extension side chamber and a pressure side chamber, respectively, and is movable in the cylinder. A shock absorber provided with a rod inserted into the piston and connected to the piston is characterized in that a reservoir is provided in the rod, and the reservoir and the pressure side chamber communicate with each other.

  In the shock absorber configured as described above, since the reservoir is provided in the rod, it is not necessary to provide a reservoir on the outer periphery of the cylinder, and the reservoir is arranged in parallel with the extension side chamber and the pressure side chamber. Therefore, the stroke length is not sacrificed unlike the single cylinder type shock absorber in which the air chamber is arranged in series with respect to the expansion side chamber and the compression side chamber.

  According to the shock absorber of the present invention, the outer diameter is not increased, the weight of the shock absorber is light, and the cost is not increased. Therefore, the shock absorber is small, light, and inexpensive.

It is a longitudinal cross-sectional view of the shock absorber in one embodiment of the present invention. It is a longitudinal cross-sectional view of the buffer in other embodiment of this invention.

  Hereinafter, the present invention will be described based on an embodiment shown in the drawings. As shown in FIG. 1, the shock absorber D in one embodiment includes a cylinder 1, an extension side chamber R <b> 1 that is slidably inserted into the cylinder 1, and is filled with liquid in the cylinder 1, and a compression side chamber, respectively. As a so-called one-rod type shock absorber, it comprises a piston 2 partitioned into R2, a rod 3 that is movably inserted into the cylinder 1 and connected to the piston 2, and a reservoir R provided in the rod 3. It is configured.

  The liquid filled in the extension side chamber R1, the pressure side chamber R2, and the reservoir R may be a fluid such as water, an aqueous solution, an electromagnetic viscous fluid, or an electroviscous fluid in addition to the hydraulic oil. Is filled with gas in addition to liquid. As the gas filled in the reservoir R, an inert gas such as nitrogen may be used.

  Hereinafter, each part of the shock absorber D will be described in detail. As shown in FIG. 1, the cylinder 1 is provided with an annular rod guide 4 that pivotally supports the rod 3 at the right end in FIG. 1, and a cap 5 that closes the cylinder end is attached at the right end in FIG. .

  Further, a piston 2 is slidably inserted into the cylinder 1, and an extension side chamber R1 into which the rod 3 is inserted by the piston 2 and a pressure side chamber R2 on the piston side are partitioned in the cylinder 1. . The piston 2 is provided with passages 2a and 2b communicating the extension side chamber R1 and the pressure side chamber R2. Damping force generating elements 6 and 7 are provided in the middle of the passages 2a and 2b. The damping force generating element 6 allows only the flow of liquid from the extension side chamber R1 to the compression side chamber R2, and gives resistance to the flow of liquid passing through the passage 2a, thereby causing a predetermined pressure loss. The damping force generating element 7 allows only the flow of liquid from the compression side chamber R2 to the extension side chamber R1, and gives resistance to the flow of liquid passing through the passage 2b, thereby causing a predetermined pressure loss. For the damping force generating elements 6 and 7, for example, a throttle valve such as an orifice or a choke can be employed in addition to a valve such as a poppet valve or a leaf valve.

  The rod 3 has a hollow portion 3a and is supported by a rod guide 4 provided at the left end of the cylinder 1 in FIG. 1, while the right end in FIG. 1 is inserted into the cylinder 1 and the piston 2 is connected to the right end. Yes. The piston 2 has an annular shape and is fixed to the outer periphery of the right end of the rod 3 in FIG. A free piston 8 is slidably inserted into the hollow portion 3 a of the rod 3, and the free piston 8 can move in the axial direction with respect to the rod 3. The free piston 8 divides the hollow portion 3 a of the rod 3 into a liquid chamber L that is filled with a liquid and a pressurizing chamber P that pressurizes the liquid chamber L via the free piston 8.

  The liquid chamber L is communicated with the pressure side chamber R2 by the pressure side attenuation passage 9 and the suction passage 10 provided at the right end of the rod 3 in FIG. In the middle of the pressure-side attenuation passage 9, only the flow of liquid from the pressure-side chamber R2 to the liquid chamber L is allowed, and resistance is given to the flow of liquid passing through the pressure-side attenuation passage 9 to cause a predetermined pressure loss. A force generation element 11 is provided, and a check valve 12 that allows only a liquid flow from the liquid chamber L to the pressure side chamber R2 is provided in the middle of the other suction passage 10.

  Further, in the pressurizing chamber P, a spring member 13 is interposed in a compressed state between the bottom 3a at the left end in FIG. 1 of the rod 3 and the free piston 8, and this spring member 13 is inserted into the free piston. The force to extend through 8 is applied to the liquid chamber L, the liquid chamber L is pressurized, and the pressure side chamber R2 and the expansion side chamber R1 are also pressurized through the liquid chamber L. The pressurizing chamber P may function as a gas spring by enclosing a gas in the pressurizing chamber P instead of the spring member 13. Thus, by pressurizing the extension side chamber R1 and the pressure side chamber R2 in the cylinder 1 with the pressurizing chamber P, the apparent rigidity of the liquid can be increased, and the damping force generation response of the shock absorber D is improved. In addition, it is possible to prevent bubbles from being generated in the cylinder 1.

  When the shock absorber D configured in this manner is extended, the piston 2 moves to the left in FIG. 1 to compress the expansion side chamber R1 and expand the opposite compression side chamber R2, so that the passage 2a from the expansion side chamber R1. Passes through the pressure side chamber R2. Further, since the shock absorber D is a single rod type, when the rod 3 is extended, the rod 3 is withdrawn from the cylinder 1, and the liquid corresponding to the outer volume of the rod 3 that has withdrawn from the liquid chamber L of the reservoir R through the suction passage 10. To R2. During this extension stroke, since the liquid passes through the damping force generating element 6, a differential pressure is generated in the extension side chamber R1 and the pressure side chamber R2, and the shock absorber D prevents the piston 2 from moving in the left direction in FIG. Demonstrates a damping force commensurate with the differential pressure.

  On the other hand, when the shock absorber D is compressed, the piston 2 moves rightward in FIG. 1 to compress the compression side chamber R2 and expand the opposite extension side chamber R1, so that it passes through the passage 2b from the compression side chamber R2. Then, the liquid moves to the extension side chamber R1. Further, since the shock absorber D is a single rod type, the rod 3 enters the cylinder 1 when compressed, and the volume of liquid that the rod 3 pushes in the cylinder 1 flows from the pressure side chamber R2 to the liquid chamber L of the reservoir R. The liquid is discharged into the liquid chamber L through the pressure-side attenuation passage 9. During this contraction stroke, since the liquid passes through the damping force generating element 11 in the compression side damping passage 9, the pressure in the pressure side chamber R2 rises, and the liquid passes through the damping force generating element 6 and passes from the compression side chamber R2 to the expansion side chamber R1. As a result, the shock absorber D exhibits a damping force commensurate with the pressure difference in a direction that prevents the piston 2 from moving to the right in FIG.

  As can be understood from the above, the reservoir R compensates the volume change in the cylinder 1 by supplying or absorbing the liquid to the cylinder 1 when the shock absorber D expands and contracts. Moreover, the buffer D can exhibit the damping force which prevents the movement of the piston 2 when expanding and contracting, similarly to the conventional buffer.

  In the shock absorber D, since the reservoir R is provided in the rod 3, it is not necessary to provide a reservoir on the outer periphery of the cylinder 1, and the reservoir R is connected to the extension side chamber R1 and the pressure side chamber R2. Since the air chambers are arranged in parallel, the stroke length is not sacrificed unlike the single cylinder type shock absorber in which the air chambers are arranged in series with respect to the extension side chamber and the compression side chamber.

  Therefore, according to the shock absorber D, the outer diameter is not increased, the weight of the shock absorber is light, and the cost is not increased. Therefore, the shock absorber D is small, light, and inexpensive.

  In addition, since the shock absorber D is provided with the reservoir R and the pressure side damping passage 9 is provided between the reservoir R and the pressure side chamber R2, a large damping force can be exerted even during the compression stroke. The damping force of the vibration target is not deficient and can be sufficiently controlled.

  Further, in the shock absorber D, the pressurizing chamber P and the liquid chamber L are partitioned, and it is not necessary to fill the liquid chamber L with gas, and the liquid chamber L can be filled with only the liquid. Since the liquid level does not occur in L, even if the entire shock absorber D vibrates, gas does not enter the liquid in the liquid chamber L, and the shock absorber D exhibits a stable damping force. Can do. The pressurization chamber P and the liquid chamber L can be separated from each other by using, for example, a bladder or a bellows in addition to the free piston 8.

  Next, the shock absorber D1 in another embodiment shown in FIG. 2 will be described. The shock absorber D1 of this other embodiment has a rod 16 in a cylindrical shape with respect to the structure of the shock absorber D of the one embodiment, and a pipe 16 that forms a reservoir R3 together with the rod 15, and a pipe 16 is different from the shock absorber D in that a partition member 18 that forms a chamber 17 between the cap 5 and the cap 5 is provided.

  Hereinafter, the point that the shock absorber D1 is different from the shock absorber D will be described in detail, and since the description of the same members as the shock absorber D is repeated, the detailed description thereof is omitted only by attaching the same reference numerals. I will do it.

  In this shock absorber D1, the rod 15 has a cylindrical shape, and the left end in FIG. The piston 2 is connected to the outer periphery of the right end of the rod 15 in FIG.

  The partition member 18 is attached to the inner periphery of the right end in FIG. 1 of the cylinder 1, and a pressure side chamber R <b> 2 is formed between the partition member 18 and the piston 2. The partition member 18 further defines a chamber 17 between the cylinder 1 and the cap 5 that closes the end in FIG. 1 of the cylinder 1, and includes a compression-side damping passage 20 and a suction passage 21. The pressure-side attenuation passage 20 communicates the pressure-side chamber R2 and the chamber 17, and in the middle of the pressure-side attenuation passage 20, only the liquid flow from the pressure-side chamber R2 toward the chamber 17 is allowed and the liquid flow passing through the pressure-side attenuation passage 20 A damping force generating element 22 that provides resistance and generates a predetermined pressure loss is provided. The other suction passage 21 communicates the pressure side chamber R2 and the chamber 17, and a check valve 23 that allows only the flow of liquid from the chamber 17 toward the pressure side chamber R2 is provided in the middle.

  The pipe 16 is connected to the pressure side chamber side of the partition member 18, passes through the pressure side chamber R <b> 2, and is inserted into the rod 15. The pipe 16 and the rod 15 form a closed space A, and the space A forms a reservoir R3. In the case of this embodiment, the outer periphery of the pipe 16 is brought into sliding contact with the inner periphery of the rod 15 to prevent the space A and the pressure side chamber R2 from communicating with each other without any resistance. A seal member may be provided between the rod 15 and the pipe 16 to prevent the communication between the space A and the compression side chamber R2. By using the seal member, the rod 15 and the pipe 16 can be processed and assembled with high accuracy. There is an advantage that it is not required.

  A free piston 24 is slidably inserted in the inner periphery of the pipe 16, and the reservoir R3 is partitioned into a liquid chamber L1 and a pressurizing chamber P1. The liquid chamber L1 communicates with the chamber 17 through a through hole 18a provided in the partition member 18, and the chamber 17 communicates with the pressure side chamber R2 via the pressure side attenuation passage 20 and the suction passage 21. Thus, the liquid chamber L1 communicates with the pressure side chamber R2. In short, the reservoir R3 communicates with the compression side chamber R2 via the chamber 17, and by doing so, the damping force generating element 22 and the check valve 23 can be provided on the partition member 18 without difficulty. When the damping force generating element 22 and the check valve 23 can be provided in the cap 5 or the pipe 16, the partition member 18 can be eliminated and the pipe 16 can be attached to the cap 5. Since the free piston 24 is disposed on the pipe 16 side, when the shock absorber D1 is compressed, the free piston 24 does not interfere with the relative movement in the axial direction of the rod 15 and the pipe 16, and the relative There is no hindrance to movement.

  Further, in the pressurizing chamber P1, a spring member 25 is interposed in a compressed state between the sealing member 19 and the free piston 24, and the spring member 25 tends to extend via the free piston 24. A force is applied to the liquid chamber L1, the liquid chamber L1 is pressurized, and the pressure side chamber R2 and the extension side chamber R1 are also pressurized through the liquid chamber L1. In addition, gas may be enclosed in the pressurizing chamber P1 instead of the spring member 25, and the pressurizing chamber P1 may function as a gas spring. The merit of pressurizing the inside of the cylinder 1 in the pressurizing chamber P1 is the same as the merit of pressurizing the pressurizing chamber P in the shock absorber D.

  The shock absorber D <b> 1 configured in this manner can exhibit a damping force that prevents the movement of the piston 2, as with the shock absorber D, when expanding and contracting. In the shock absorber D1, since the reservoir R3 is provided in the rod 15 and the pipe 16, there is no need to provide a reservoir on the outer periphery of the cylinder 1, and the reservoir R3 includes the extension side chamber R1 and the pressure side chamber R2. Therefore, the stroke length is not sacrificed unlike the single cylinder type shock absorber in which the air chamber is arranged in series with respect to the extension side chamber and the compression side chamber.

  Therefore, according to the shock absorber D, the outer diameter is not increased, the weight of the shock absorber is light, and the cost is not increased. Therefore, the shock absorber D is small, light, and inexpensive.

  Furthermore, since not only the inside of the rod 15 but also the inside of the pipe 16 contributes to the volume of the reservoir R3, when the large-diameter rod 15 is used, the amount of liquid exchanged between the reservoir R3 and the cylinder 1 during the expansion / contraction stroke increases. However, there is no shortage of volume, and the effect of preventing the buffer D1 from becoming larger in diameter is further increased, which is more advantageous by downsizing the buffer D1.

  Further, even in the shock absorber D1, since the reservoir R3 is provided and the pressure side damping passage 22 is provided between the reservoir R3 and the pressure side chamber R2, a large damping force can be exhibited even during the compression stroke. Therefore, it is possible to sufficiently control the vibration of a large vibration control object without a dampening force.

  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.

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston 3 Rod 5 Cap 8, 24 Free piston 9, 20 Pressure side damping passage 10, 21 Suction passage 13, 25 Spring member 16 Pipe 17 Chamber 18 Partition member 19 Sealing member A Space D, D1 Buffer R, R3 Reservoir R1 Extension side chamber R2 Pressure side chamber

Claims (6)

A cylinder, a piston that is slidably inserted into the cylinder and divides the cylinder into an extension side chamber and a pressure side chamber that are filled with liquid, and a cylinder that is slidably inserted into the cylinder and connected to the piston A shock absorber provided with a rod that is provided with a reservoir in the rod that compensates for a volume change in the cylinder accompanying expansion and contraction, and the reservoir and the pressure side chamber communicate with each other. Between the reservoir and the pressure-side chamber, a pressure-side attenuation passage that provides resistance to the flow of the liquid while allowing only the flow of the liquid from the pressure-side chamber to the reservoir, and the liquid flowing from the reservoir to the pressure-side chamber The shock absorber according to claim 1, further comprising a suction passage that allows only a flow. A partition member that is fixed to the cylinder and forms a pressure side chamber together with the piston; and a pipe that is connected to the partition member and communicates with the pressure side chamber. The shock absorber according to claim 1 or 2, wherein the pipe is inserted therein and the reservoir is formed in a space formed by the rod and the pipe. A cap for closing the pressure side chamber side end of the cylinder and forming a chamber with the partition member is provided, the pressure member damping passage and the suction passage are provided in the partition member, and the inside of the pipe communicates with the chamber. The shock absorber according to claim 3, wherein A free piston that is slidably inserted into the pipe, and the free piston divides the space into a liquid chamber on the pipe side and a pressurizing chamber on the rod side that pressurizes the liquid chamber; The shock absorber according to claim 3 or 4, wherein the shock absorber is formed. The sealing member which seals the non-cylinder side end of the rod, and a spring member which pressurizes the liquid chamber between the sealing member and the free piston are provided. Shock absorber.

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