JP2009299769A - Hydraulic shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic shock absorber for reducing a working liquid quantity. <P>SOLUTION: For attaining the purpose, the hydraulic shock absorber D includes a cylinder 1, a rod 2 movably inserted into the cylinder 1, and a piston 3 connected to the rod 2, slidingly inserted into the cylinder 1 and partitioning the inside of the cylinder 1 into two pressure chambers R1 and R2, and is characterized in that an inner diameter of a part or the whole of the cylinder 1 outside of a piston stroke range is set to a smaller diameter than a piston outer diameter. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hydraulic shock absorber.

  In a conventional hydraulic shock absorber, for example, a cylinder, a rod inserted into the cylinder, and a rod connected to the rod and slidably inserted into the cylinder are divided into two pressure chambers. And a piston to be configured.

  In such a hydraulic shock absorber, in order to buffer the impact at the time of maximum extension, a cushion that can be engaged with a rod guide that seals the cylinder end and pivotally supports the piston rod is provided on the outer periphery of the piston rod. (For example, refer to Patent Documents 1 and 2).

When the bending moment is applied by the force input from the lateral direction, the hydraulic shock absorber receives this at the sliding part of the piston and cylinder and the sliding part of the piston rod and rod guide, and the maximum extension. In order to increase the bending strength at the time, it is necessary to secure a certain distance between the sliding parts at the maximum extension, and the cushion and the rod guide are brought into contact with each other to restrict further approaching between the sliding parts. In other words, the maximum extension length is regulated by the collision between the cushion and the rod guide.
Japanese Patent Laid-Open No. 9-14328 (FIG. 1) Japanese Patent Laying-Open No. 2008-38971 (FIG. 1)

  When increasing the damping force generated by the hydraulic shock absorber as described above and improving the response of the damping force generation, it is conceivable to set the piston outer diameter large. Further, the inner diameter of the cylinder is increased, and the amount of the working liquid filled in the cylinder is increased, resulting in an increase in the weight of the hydraulic shock absorber.

  Further, since the maximum extension length of the hydraulic shock absorber is regulated as described above, the stroke length of the piston is shorter than the cylinder length, and a part of the cylinder length does not contribute to the stroke length. Therefore, there is a waste of having to fill the working liquid into the cylinder which does not contribute to the stroke length.

  Therefore, the present invention has been developed to improve the above-described problems, and an object of the present invention is to provide a hydraulic shock absorber capable of reducing the amount of working fluid.

  In order to achieve the above object, the problem solving means of the present invention includes a cylinder, a rod that is slidably inserted into the cylinder, and a rod that is coupled to the rod and is slidably inserted into the cylinder. In a hydraulic shock absorber provided with a piston partitioned into two pressure chambers, the inner diameter of a part or all of the cylinder outside the piston stroke range is set smaller than the outer diameter of the piston.

  According to the hydraulic shock absorber of the present invention, the inner diameter of the portion that does not affect the piston stroke of the cylinder is set smaller than the outer diameter of the piston, so that the cylinder has a large diameter and the same inner diameter over the entire length. The volume in the cylinder of the conventional hydraulic shock absorber to be set is smaller, and accordingly, the amount of working liquid required for the hydraulic shock absorber can be reduced and the weight can be reduced.

  Therefore, even if the piston outer diameter is increased in order to increase the generated damping force and improve the response of the damping force generation, the inner diameter of the portion that does not affect the piston stroke of the cylinder is thus increased. Since the increase in the cylinder internal volume can be suppressed by making the diameter smaller than the outer diameter of the piston, it is possible to suppress the increase in the amount of the working liquid to an increase in the generated damping force and the improvement in the response of the generation of the damping force.

  In addition, in the case of providing an outer cylinder that forms a reservoir between the cylinder and the outer periphery of the cylinder, the volume in the reservoir can be increased by reducing the volume in the cylinder, and the gas pressure fluctuation in the reservoir can be reduced. It is possible to increase the generated damping force and improve the response of the damping force generation by setting the pressure in the reservoir high while maintaining the pressure resistance strength of the seal member.

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

  As shown in FIG. 1, a hydraulic shock absorber D according to an embodiment includes a cylinder 1, a rod 2 that is movably inserted into the cylinder 1, a rod 2, and a slide within the cylinder 1. A piston 3 that is freely inserted and divides the inside of the cylinder 1 into two pressure chambers R <b> 1 and R <b> 2 and an outer cylinder 4 that covers the outer periphery of the cylinder 1 are provided.

  The pressure chambers R1 and R2 are filled with a working liquid, and a reservoir R for compensating for a change in the cylinder volume corresponding to the volume of the rod 2 protruding from the cylinder 1 is provided between the cylinder 1 and the outer cylinder. In this embodiment, the reservoir R communicates with the pressure chamber R2 and is filled with a working liquid and a gas. In addition, the hydraulic fluid should just be a fluid which a hydraulic pressure buffer can exhibit damping force, for example, hydraulic fluid is used.

  In the following, each member will be described in detail. The cylinder 1 has an inner diameter that is set to a diameter that allows the outer periphery of the piston 3 to be in sliding contact, and an inner diameter that is set to be smaller than the outer diameter of the piston 3. A small-diameter cylindrical portion 1b, and a connecting ring 1c that is interposed between the large-diameter cylindrical portion 1a and the small-diameter cylindrical portion 1b and engages with the upper end of the large-diameter cylindrical portion 1a and the lower end of the small-diameter cylindrical portion 1b. The small-diameter cylindrical portion 1b is arranged above the large-diameter cylindrical portion 1a, and a stepped portion is formed between the large-diameter cylindrical portion 1a and the small-diameter cylindrical portion 1b by the connecting ring 1c.

  A rod guide 5 that slidably supports the rod 2 is fitted and closed in the upper end opening of the small diameter cylindrical portion 1 b that is the upper end of the cylinder 1, and the large diameter cylindrical portion 1 a that is the lower end of the cylinder 1. The bottom member 6 is fitted and closed at the lower end opening.

  The rod 2 is movably inserted into the cylinder 1 described above, and a piston 3 is connected to the lower end of the rod 2 in FIG. Further, on the outer periphery of the rod 2, a flange 2a is provided above the piston 3, and an annular cushion 7 supported by the flange 2a is mounted.

  When the hydraulic shock absorber D extends, the cushion 7 moves upward with respect to the cylinder 1 and finally comes into contact with the lower end of the connecting ring 1c that becomes the stepped portion of the cylinder 1 as shown in FIG. In this state, the rod 2 is prevented from further rising, and the maximum extension length of the hydraulic shock absorber D is regulated. At the maximum extension, it collides with the connecting ring 1c to reduce the shock at the maximum extension. It is supposed to be.

  Further, a bottomed cylindrical outer cylinder 4 that covers the cylinder 1 and forms a reservoir R between the cylinder 1 and the cylinder 1 is provided outside the cylinder 1. The rod guide 5 is fitted and the bottom member 6 is seated on the bottom of the lower end.

  1 is provided on the outer periphery of the upper end of the outer cylinder 4 in FIG. 1, and a cap 8 covering the upper end of the outer cylinder 4 in FIG. The bottom part of the outer cylinder 4 is sandwiched between the rod guide 5, the cylinder 1 and the bottom member 6, and these members are fixed to the outer cylinder 4.

  An annular seal member 9 is interposed between the cap 8 and the rod guide 5, the outer periphery of the rod 2 is sealed by the seal member 9, the upper end of the cylinder 1 is sealed, and the working liquid is sealed. Leakage outside the cylinder 1 is prevented.

  When the rod guide 5, the cylinder 1 and the bottom member 6 are fixed to the outer cylinder 4, the cap 8 is not used, and the upper end opening of the outer cylinder 4 is crimped from the outer peripheral side to the rod guide 5 downward in the figure. The outer cylinder 4 may be fixed by applying an axial force, and the lower end of the outer cylinder 4 may be closed as a simple cylinder instead of a bottomed cylinder.

  Subsequently, the piston 3 is connected to the lower end of the rod 2 in FIG. 1 and is in sliding contact with the inner periphery of the large-diameter cylindrical portion 1a in the cylinder 1, and within the range of the axial length of the large-diameter cylindrical portion 1a. Strokes with. That is, in the case of this embodiment, the hydraulic shock absorber D is set to a single rod type.

  In addition, the piston 3 includes passages 3a and 3b that connect the pressure chamber R1 disposed above in FIG. 1 and the pressure chamber R2 disposed below. The leaf valve 10 is stacked on the upper end of the piston 3, the upper end of the passage 3 a is opened and closed by the leaf valve 10, the leaf valve 11 is stacked on the lower end of the piston 3, and the lower end of the passage 3 b is opened and closed by the leaf valve 11. It has come to be. That is, the leaf valve 10 prevents the flow of the working liquid from the pressure chamber R1 to the pressure chamber R2, and gives resistance to the flow of the working liquid from the pressure chamber R2 to the pressure chamber R1. The leaf valve 11 prevents the flow of the working liquid from the pressure chamber R2 to the pressure chamber R1, and gives resistance to the flow of the working liquid from the pressure chamber R1 to the pressure chamber R2.

  Further, the bottom member 6 is provided with passages 6a and 6b communicating between the reservoir R formed between the cylinder 1 and the outer cylinder 4 and the pressure chamber R2, and the upper end of the passage 6a is shown in FIG. The lower end of the other passage 6b is opened and closed by a leaf valve 13 stacked at the lower end in FIG. 1 of the bottom member 6. That is, the check valve 12 blocks the flow of the working liquid from the pressure chamber R2 to the reservoir R, and the other leaf valve 13 blocks the flow of the working liquid from the reservoir R to the pressure chamber R2, and the pressure chamber R2 Resistance to the flow of the working liquid from to the reservoir R.

  Therefore, in the hydraulic shock absorber D, when the rod 2 moves upward in FIG. 1 with respect to the cylinder 1, the operation is directed from the pressure chamber R2 to the pressure side chamber R1 via the passage 3b of the piston 3. A resistance is given to the flow of the liquid by the leaf valve 11 to cause a predetermined pressure loss, and a predetermined extension side damping force is generated in the hydraulic pressure buffer D. At the time of this extension operation, the check valve 12 is opened, and the volume of working liquid with which the rod 2 is withdrawn from the cylinder 1 is supplied from the reservoir R into the cylinder 1 through the passage 6a to compensate for the volume in the cylinder 1. The When a working liquid flows from the reservoir R into the cylinder 1, if it is desired to provide resistance to the flow of the working liquid, a damping valve such as a leaf valve is used instead of the check valve 12 to open and close the passage 6a. You may do it.

  On the other hand, at the time of compression operation in which the rod 2 moves downward in FIG. 1 with respect to the cylinder 1, the volume of working liquid in which the rod 2 enters the cylinder 1 becomes excessive in the cylinder 1, and the cylinder 1 passes through the passage 6b. The working liquid is discharged from the inside to the reservoir R, and resistance is given to the flow of the working liquid by the leaf valve 13 to increase the pressure in the cylinder 1. In the case of this hydraulic shock absorber D, during the compression operation, the damping force on the compression side is generated in the hydraulic pressure shock absorber D mainly by the pressure increase in the cylinder 1 by the leaf valve 13, but the hydraulic pressure shock absorber of this embodiment In D, a resistance is given by a leaf valve 10 to the flow of hydraulic oil from the pressure chamber R2 toward the pressure chamber R1 via the passage 3a of the piston 3, and the leaf valve 10 includes the pressure chamber R1 and the pressure chamber A differential pressure is generated in R2 to increase the pressure-side damping force of the hydraulic shock absorber D, thereby contributing to the generation of the pressure-side damping force of the hydraulic pressure buffer D. It should be noted that the leaf valve 10 may be replaced with a simple check valve, particularly when there is no need to generate a pressure loss when the working liquid passes through the passage 3a and to expect generation of a compression-side damping force.

  In the hydraulic shock absorber D configured as described above, as described above, the cylinder 1 includes the small-diameter cylindrical portion 1b having an inner diameter smaller than the outer diameter of the piston 3, and this small-diameter cylindrical portion. 1 b is located outside the stroke range of the piston 3, that is, in a range where the piston 3 cannot face even if the hydraulic shock absorber D expands and contracts, and does not affect the stroke of the piston 3. In other words, the portion that does not affect the stroke of the piston 3 of the cylinder 1 is the small-diameter cylindrical portion 1b.

  Therefore, the volume of the hydraulic shock absorber D in the cylinder 1 is set to the same inner diameter with a large diameter over the entire length by providing a small diameter portion, in this case, the small diameter cylindrical portion 1b. Since the volume of the hydraulic shock absorber is smaller than that in the cylinder, the amount of hydraulic fluid required for the hydraulic pressure shock absorber D can be reduced correspondingly, and the weight can be reduced.

  Therefore, even if the outer diameter of the piston 3 is increased in order to increase the generated damping force and to improve the response of the damping force generation, the portion that does not affect the piston stroke of the cylinder 1 in this way. Since the inner diameter can be made smaller than the outer diameter of the piston 3 and the increase in the volume in the cylinder can be suppressed, the increase in the amount of the working liquid can be suppressed low with respect to the increase in the generated damping force and the improvement in the response of the generated damping force It is.

  In this embodiment, the cylinder 1 is provided with a small-diameter portion, that is, in this embodiment, a small-diameter cylindrical portion 1b, and the outer diameter of the small-diameter cylindrical portion 1b is smaller than that of the large-diameter cylindrical portion 1a. Therefore, the internal volume of the reservoir R can be increased by the amount that the internal volume of the cylinder 1 decreases.

  Then, the volume occupied by the gas in the volume of the reservoir R can be increased, and the volume occupied by the gas in the reservoir R in the most expanded state and the gas in the reservoir R in the most contracted state occupy the hydraulic buffer D. The amount of change in volume can be reduced, and the gas pressure fluctuation in the reservoir R is reduced. Therefore, even when the pressure in the reservoir R is set high to increase the generated damping force or to improve the response of the damping force generation, the increase in the pressure in the reservoir R when the hydraulic shock absorber D is contracted most Therefore, it is not necessary to set the pressure resistance strength of the seal member 9 unnecessarily high. In other words, by increasing the pressure in the reservoir R while keeping the pressure resistance strength of the seal member 9 as it is, it is possible to increase the generated damping force and improve the response of the damping force generation.

  Further, in the case of this embodiment, the stepped portion of the cylinder 1, the linkage ring 1c forming the stepped portion is brought into contact with the cushion 7 mounted on the outer periphery of the rod 2, and the maximum extension length is regulated. Therefore, the small diameter portion of the cylinder 1 can be set to be smaller than the outer diameter of the cushion 7, and the amount of working liquid can be further reduced.

  Moreover, the cylinder 1 is comprised by three pieces of the connection ring 1c which the cylinder 1 fits in the large diameter cylinder part 1a, the small diameter cylinder part 1b, the large diameter cylinder part 1a, and the small diameter cylinder part 1b as mentioned above. However, the small diameter portion may be formed by setting the outside of the stroke range of the piston 3 in the cylinder constituted by a single cylinder to a small diameter, but the large diameter cylindrical portion 1a and the small diameter cylindrical portion 1b are connected to each other. By constructing the cylinder 1 with the three pieces 1c, there is an advantage that the assembly work of the hydraulic shock absorber D set to a single rod type is simplified. That is, when assembling the cylinder 1 in the outer cylinder 4, if the cylinder 1 is a single cylinder, a cylinder 3 assembled with the rod 2 due to the presence of a small diameter portion is inserted into the cylinder 1 in advance. However, when the cylinder 1 is composed of three pieces, the large-diameter cylindrical portion 1a is inserted into the outer cylinder 4 after the assembly. The assembly of the piston 3 and the rod 2 is inserted into the large-diameter cylindrical portion 1a, and then the connecting ring 1c and the small-diameter cylindrical portion 1b can be assembled sequentially, so that the assembling work is simplified. Furthermore, when a load is applied to the connecting ring 1c from the large-diameter portion 1a and the small-diameter portion 1b, a shearing force acts, but there is an advantage that securing the strength is facilitated by using the connecting ring 1c as a separate member. In order to simplify the assembling operation, the connecting ring 1c is eliminated, the lower end of the small diameter cylindrical portion 1b is expanded so that it can be fitted to the upper end of the large diameter cylindrical portion 1a, and the cylinder 1 is connected to the small diameter cylindrical portion 1b. And the large-diameter cylindrical portion 1a.

  In the above description, the hydraulic shock absorber D is described as a single rod type shock absorber. However, even in a hydraulic shock absorber set to a double rod type, the piston strokes over the entire length of the cylinder. The present invention can be embodied in a hydraulic pressure buffer having a waste length that does not exist, and the effects of the present invention can be achieved.

  Further, the above-described various advantages can be enjoyed by setting the hydraulic shock absorber D to a so-called double cylinder type hydraulic shock absorber in which the reservoir R is formed in the gap between the cylinder 1 and the outer cylinder 4. However, it is a matter of course that the hydraulic shock absorber D can be embodied as a single cylinder shock absorber, and this does not hinder this.

  Furthermore, in the case of this embodiment, the upper end side in FIG. 1 of the cylinder 1 facing the rod 2 is set to a small diameter, but the piston 3 does not stroke even if it is on the lower end side in FIG. In this case, the inner diameter may be set smaller than the outer diameter of the piston 3.

  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 shock absorber in one embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder 1a Large diameter cylinder part 1b Cylinder small diameter cylinder part 1c Cylinder connecting ring 2 Rod 2a 鍔 3 Piston 3a, 3b Piston passage 4 Outer cylinder 4a Outer cylinder screw part 5 Rod guide 6 Bottom members 6a, 6b Screw portion 7 in bottom member Cushion 8 Cap 9 Seal member 10, 11, 13 Leaf valve 12 Check valve D Hydraulic shock absorber R Reservoir R1, R2 Pressure chamber

Claims (4)

Hydraulic shock absorber comprising a cylinder, a rod that is movably inserted into the cylinder, and a piston that is connected to the rod and is slidably inserted into the cylinder to partition the cylinder into two pressure chambers A hydraulic shock absorber characterized in that a part or all of the inner diameter of the cylinder outside the piston stroke range is set smaller than the outer diameter of the piston. The liquid according to claim 1, wherein an outer cylinder covering the outer periphery of the cylinder is provided, and a reservoir is formed which is communicated with the pressure chamber through a gap between the cylinder and the outer cylinder and is filled with liquid and gas. Pressure buffer. The cushion is attached to the outer periphery of the rod, and the maximum extension length is regulated by abutting the cushion against a step portion between a small diameter portion and a large diameter portion of the cylinder. Hydraulic buffer. The cylinder has an inner diameter that is set to a diameter that allows the outer periphery of the piston to be slidably contacted, a large-diameter cylindrical portion that is fitted to the bottom member, an inner diameter that is set to be smaller than the outer diameter of the piston, and a rod that slides. A small-diameter cylindrical portion that is fitted to a rod guide that pivotally supports, and is interposed between the large-diameter cylindrical portion and the small-diameter cylindrical portion, and is fitted to the upper end of the large-diameter cylindrical portion and the lower end of the small-diameter cylindrical portion. The hydraulic shock absorber according to any one of claims 1 to 3, comprising a continuous ring.

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