JP2005172128A - Oil-filled shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oil-filled shock absorber having predetermined stable shock absorbing performance without damaging a seal sliding material at the same time of oil normally flowing out and capable of being easily manufacturing in an simple structure. <P>SOLUTION: A plurality of orifices 3 are provided vertically apart from each other at a cylinder 2 for forming an oil chamber and a piston head 8 slidably fitting with the cylinder 2 is provided to a piston 6 inserted into the oil chamber. A sealing sliding material 12 made of semi-hardened elastic resin for sliding at an inner periphery of the cylinder 2 is fit with a fit groove 10 of an outer periphery of the piston head 8 and the sealing sliding material 12 is pressed from inside to outside by providing a backup ring 11 made of a viscoelastic material fit with the fitting groove 10. Thus, the sealing sliding material 12 is fit with the cylinder 2 with predetermined contact pressure by the backup ring 11 and does not intrude in the orifice 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention mainly relates to an oil-filled shock absorber that is erected in a pit of an elevator hoistway to buffer an abnormal lowering operation of a lifting body such as an elevator car.

  As a conventional oil-filled shock absorber, there is a porous orifice type hydraulic shock absorber. In the hydraulic shock absorber of this aspect, both the oil chamber A and the oil chamber B are formed by a cylinder, and a plurality of orifices communicated with the both. Are arranged apart from each other in the longitudinal direction of the cylinder. These orifices are sequentially closed as the piston descends to reduce the opening area of the orifices, and increase the hydraulic resistance due to the oil flowing out from the oil chamber A to the oil chamber B.

  Thereby, the descending speed of the piston is decelerated, and the abnormal descending operation of the lifting body such as an elevator car is buffered. In the conventional oil-filled shock absorber, a gap is formed at the sliding portion between the piston head and the cylinder, or a metal C-shaped or spiral-shaped piston ring is provided on the outer periphery of the piston head. (For example, refer to Patent Document 1).

Japanese Patent Laid-Open No. 10-114480 (summary, FIG. 1)

  In the conventional oil-filled shock absorber configured as described above, when a gap is formed between the piston head and the cylinder, not only the opening area of the orifice of the cylinder but also the oil flows out from the gap. As the amount of outflow increases, the hydraulic resistance decreases. In addition, there is a problem in that it is difficult to obtain a stable buffer performance because the oil outflow area due to the gaps described above changes due to manufacturing dimensional errors of the piston head and cylinder.

On the other hand, if the allowable range of the manufacturing dimensional error of the cylinder or the like is narrowed, the manufacturing cost increases although the stable buffer performance of the oil-filled shock absorber can be obtained.
When the piston head is equipped with a piston ring, the cylinder may be scratched or abnormally worn due to broken piston rings or poor lubrication.

  Also, like an oil-filled shock absorber of an orifice-control rod type or a general hydraulic cylinder, a rubber elastic body such as an O-ring is provided on the sliding portion so that the elastic body slides directly on the cylinder. It is possible. However, when an elastic body is provided in the sliding part, the elastic body enters the orifice when the elastic body passes through the orifice of the cylinder, the elastic body is damaged, and the oil tightness is lost, and the required buffer performance is obtained. It becomes impossible.

  Furthermore, in the case of an orifice-control rod type oil-filled shock absorber, since only the piston rod is fitted to the cylinder, the concentricity and slidability of the piston in operation with respect to the cylinder are not guaranteed. Therefore, it is necessary to use different materials for the piston head and the cylinder in order to prevent the piston rod from seizing and the like, which is expensive.

  The present invention has been made to solve such problems, and an object thereof is to obtain an oil-filled shock absorber that has a simple configuration and can be easily manufactured and has a required stable buffer performance. To do.

  In the oil-filled shock absorber according to the present invention, an oil chamber is formed, a cylinder in which a plurality of orifices are arranged apart from each other in the longitudinal direction, a piston that is inserted into the oil chamber and moves up and down, and a cylinder that is formed in the piston And a semi-rigid elastic resin seal that slidably rubs the inner periphery of the cylinder, and is fitted into a ring groove that is annularly formed and recessed in the outer periphery of the piston head. A sliding material and a backup ring made of a viscoelastic material that is fitted in the fitting groove and is arranged inside the sealing sliding material and presses the sealing sliding material outward are provided.

  The oil-filled shock absorber according to the present invention maintains a predetermined contact pressure on the inner surface of the cylinder by the seal sliding material made of semi-rigid elastic resin that rubs the inner circumference of the cylinder being pressed outward by the backup ring. The seal sliding material slides in the state where Also, the seal sliding material passes through the plurality of orifices as the piston descends. However, since the seal sliding material is made of tetrafluoroethylene resin or the like, it passes through each orifice without entering the orifice.

  Therefore, it is possible to eliminate the problem that it is difficult to obtain the required stable buffer performance due to the amount of oil flowing out from the gap between the piston head and the cylinder. Further, since the seal sliding material does not enter when passing through the orifice and no damage occurs, the oil tightness can be easily maintained, and there is an effect of obtaining a stable required buffer performance. Further, the seal sliding material slides on the inner surface of the cylinder while maintaining a predetermined contact pressure. For this reason, even if the allowable range of manufacturing dimensional errors such as pistons and cylinders is widened, the required stable buffer performance can be easily obtained, and the manufacturing cost can be reduced.

Embodiment 1 FIG.
1 and 2 are views showing an embodiment of the present invention. FIG. 1 is a conceptual longitudinal sectional view, and FIG. 2 is an enlarged view of a portion A in FIG. In the figure, a cylinder 2 is provided in a standing state in a space in a base body 1 made up of a cylindrical body standing on a base plate and an upper plate that closes an upper end of the cylindrical body. A plurality of orifices 3 are provided in the cylinder 2 and are arranged apart from each other in the longitudinal direction of the cylinder 2. An A oil chamber 4 is formed in the cylinder 2, and a B oil chamber 5 is formed between the base 1 and the cylinder 2.

  The piston 6 is constituted by a piston rod 7 and a piston head 8 provided at the lower end of the piston rod 7. Then, the piston rod 7 is inserted through the upper plate of the base 1 through a seal and a bearing 9, and the piston head 8 is fitted into the cylinder 2. A backup ring 11 made of a viscoelastic material is fitted into a fitting groove 10 that is annularly provided in the outer periphery of the piston head 8. The backup ring 11 is an O ring or a square ring made of a viscoelastic material such as rubber.

  An annular seal sliding member 12 made of an elastic semi-rigid resin such as tetrafluoroethylene resin or polyamide resin is fitted on the outer periphery of the backup ring 11 and fitted in the fitting groove 10. Combined, the inner periphery of the cylinder 2 is rubbed and moved. A spring receiving plate 13 is attached to the upper end portion of the piston rod 7, and a return spring 14 including a compression coil spring is provided between the upper plate of the base 1 and the spring receiving plate 13. Further, a rubber bump 15 is attached to the upper end surface of the piston rod 7.

  In the oil-filled shock absorber configured as described above, the seal sliding member 12 made of a semi-rigid elastic resin that rubs the inner periphery of the cylinder 2 is pressed outward by the backup ring 11 and is normally returned by the return spring 14. The piston 6 is held in the raised position. When the lifting and lowering body such as an elevator car descends abnormally and pushes down the piston 6, the oil flows from the A oil chamber 4 to the B oil chamber 5 through the orifice 3 by the lowering operation of the piston head 8.

  Thereby, the descending speed of the piston 6 is decelerated by the hydraulic resistance of the oil flowing out, and the opening area by the orifice 3 gradually decreases as the piston 6 descends. For this reason, the hydraulic resistance gradually increases, and the abnormal lowering operation of the elevator lifting body is buffered by the predetermined deceleration. In addition, since the seal sliding material 12 is pressed outward by the backup ring 11, the seal sliding material 12 slides while maintaining a predetermined contact pressure on the inner surface of the cylinder 2.

  Further, as the piston 6 descends, the seal sliding material 12 passes through the plurality of orifices 3. However, since the seal sliding material 12 is made of ethylene tetrafluoride resin or the like, it does not enter the orifice 3 and each orifice. Pass 3 In the above-described configuration, it is possible to eliminate the problem that it is difficult to obtain the required stable buffer performance due to the amount of oil flowing out from the gap between the piston head 8 and the cylinder 2.

  Further, since the seal sliding material 12 does not enter when passing through the orifice 3 and no damage occurs, the oil tightness can be easily maintained and a stable buffer performance can be obtained. Further, since the seal sliding material 12 slides on the inner surface of the cylinder 2 while maintaining a predetermined contact pressure, the required stable stability can be easily achieved even if the allowable range of manufacturing dimensional errors of the piston 6 and the cylinder 2 is expanded. Buffer performance can be obtained. Further, the moving resistance of the piston 6 can be reduced as compared with the configuration in which the piston head 8 is provided only with an elastic body that slides on the inner surface of the cylinder 2, and the required stable buffer performance can be easily obtained.

Embodiment 2. FIG.
FIG. 3 is a view showing another embodiment of the present invention and corresponds to FIG. 2 described above. Except for FIG. 3, an oil-filled shock absorber is configured in the same manner as the above-described embodiment of FIGS. 1 and 2. In the figure, the same reference numerals as those in FIGS. 1 and 2 indicate the corresponding parts, and the sub-fitting grooves 16 are provided on the upper side and the lower side of the fitting groove 10 of the piston head 8, respectively. A sliding ring 17 made of a semi-rigid elastic resin such as a tetrafluoroethylene resin or a polyamide resin is fitted in each of the sub-fitting grooves 16 to perform a bearing function in the piston head 8.

  Also in the oil-filled shock absorber configured as described above, the seal sliding material 12 made of a semi-rigid elastic resin that rubs the inner periphery of the cylinder 2 is pressed outward by the backup ring 11. For this reason, the seal sliding material 12 slides while maintaining a predetermined contact pressure on the inner surface of the cylinder 2. Further, when the piston 6 descends, the seal sliding material 12 passes through the plurality of orifices 3. However, since the seal sliding material 12 is made of a semi-rigid elastic resin, it does not enter the orifices 3 and each of the orifices 3 is moved. pass. Therefore, although the detailed description is omitted, the same operation as the embodiment of FIGS. 1 and 2 can be obtained also in the embodiment of FIG.

  3, the piston 6 is supported on the base 1 by the bearing 9 provided on the upper plate of the base 1 on the piston rod 7, and is supported on the cylinder 2 by the sliding ring 17 on the piston head 8. . Therefore, the piston 6 is supported on the base 1 side at two upper and lower portions, and concentricity and slidability with respect to the base 1 and the cylinder 2 are ensured during the up-and-down operation, and a stable buffer performance can be obtained.

  Further, even when an unbalanced load is applied to the piston 6 due to an abnormal lowering of a lifting body such as an elevator car, the unbalanced load is supported by the piston 6 by the two bearing functions of the bearing 9 and the sliding ring 17 at this time. Is done. Accordingly, the smoothness of the piston 6 during the up-and-down operation is improved, and it is not necessary to use different materials for the piston head 8 and the cylinder 2 in order to prevent seizure, and an increase in manufacturing costs due to using different materials can be suppressed. it can.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows Embodiment 1 of this invention, and is a longitudinal cross-sectional view shown notionally. The A section enlarged view of FIG. FIG. 2 is a view corresponding to FIG. 2 showing a second embodiment of the present invention.

Explanation of symbols

  2 cylinder, 3 orifice, 4 A oil chamber (oil chamber), 5 B oil chamber (oil chamber), 6 piston, 8 piston head, 10 fitting groove, 11 backup ring, 12 seal sliding material, 16 sub-fitting Groove (fitting groove), 17 sliding ring.

Claims (2)

  A cylinder that forms an oil chamber and a plurality of orifices are arranged apart from each other in the longitudinal direction, a piston that is inserted into the oil chamber and moves up and down, and a piston that is formed in the piston and is slidably fitted into the cylinder. A piston head, a semi-rigid elastic resin seal sliding material which is manufactured in an annular shape and fitted in a fitting groove recessed in the outer periphery of the piston head, and rubs the inner periphery of the cylinder; An oil-filled shock absorber provided with a back-up ring made of a viscoelastic material that is fitted in a fitting groove and disposed inside the seal sliding material and presses the seal sliding material outward.   A slide made of semi-rigid elastic resin that is placed away from the seal sliding material in the longitudinal direction of the piston and is fitted in another fitting groove recessed in the outer periphery of the piston head and rubs the inner periphery of the cylinder. The oil-filled shock absorber according to claim 1, further comprising a ring.

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