JPS58178034A - Cylinder device - Google Patents

Abstract

PURPOSE:To improve the shock absorbing characteristic of a cylinder for a hydraulic shock absorber, by fixing a piston to one end of a piston rod movably in predetermined range while making the oil pressure resistance characteristic variable in step in accordance with the piston speed. CONSTITUTION:A small diameter section 6A is formed at the inner end of a piston rod 6 projecting through a rod guide 3 into a cylinder 1, then a piston 21 is fitted to said section 6A movably in the axial direction. Said range is limited by a limiting section consisting of a rising step section 6B and a stopper 22. A path 23 conducting between the oil chambers B, C is formed on the piston 21 while an orifice 24 conducting between the path 23 and the oil chamber B is formed. A belleville spring 26 opening to the stopper 22 side provided with two notches 26 is placed between said piston 21 and stopper 22 to deform in accordance to the external force functioning onto the piston rod 6 thus to vary the oil pressure resistance in step.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a piston-piston rod assembly consisting of a piston and a piston rod that is slidably disposed within a cylinder, and that the piston-piston rod assembly is moved in either an extension side or a contraction side. The present invention relates to cylinder devices such as so-called one-sided hydraulic shock absorbers and gas snoring devices that generate damping force when displaced.

FIG. 1 shows a hydraulic shock absorber as a cylinder device according to the prior art.

In the figure, 1 is a cylinder, one end of which is covered with a cap, and the other end is covered with a rod guide 3.
and a seal member 4 is fitted. 5 is cylinder 1
A piston 6 is slidably provided inside the rod guide 3.
The seal member 4 is indicated by Jl, and a piston rod is shown projecting outside the cylinder 1, and the piston 5 and the piston lower drawer constitute a piston-piston rod assembly. A small diameter portion 6A is formed at the tip of the piston rod 6 on the inner side of the cylinder 1, and the piston 5 is fitted into the small diameter portion 6A so as to be movable in the axial direction thereof.

Further, an annular stop horn 'e7 is fixedly provided at the tip of the small diameter portion 6A of the piston lower drawer, and the piston 5 connects between the stop horn f7 and the rising step portion 6B formed on the piston rod 6. The stopper 7 and the stepped portion 6B form a restriction portion that restricts the movement range of the piston 5.

Next, 8 is a free piston that is slidably inserted into the cage 2 side of the cylinder 1, and the free piston/8
An air chamber A is formed between the free piston 8 and the piston 5 and between the piston 5 and the seal member 4, and oil chambers B and C are formed and filled with oil. has been done.

The piston 5 has a passage 9 that communicates between the oil chambers B and C.
As shown in FIG. An orifice 10 is formed in the stopper J?7, and the orifice 10 directs the oil from the oil chamber C when the piston 5 comes into contact with the stopper 7. The minus side thereof is open to the passage 9 so that the oil flows through the oil chamber B while generating a predetermined flow resistance.

13゜1 and 12 are seal members provided on the piston 5 and the free piston 8, respectively.
4 are the base end of the piston rod and the cap 2, respectively.
Shows the bracket attached to.

The hydraulic shock absorber according to the prior art has the above-mentioned structure, and its operation will be explained next.

First, when an external force is applied to the piston rod 6 in the direction of arrow a in the figure, the piston rod 6 is displaced in the direction of contraction. At this time, since the piston 5 is in contact with the inner wall of the cylinder 1 with a predetermined male force, the piston rod 6 moves to a position where the stepped portion 6B contacts the piston 5. When the piston 5 and the stepped portion 6B come into contact with each other, the relative movement of the piston 5 with respect to the piston rod 6 is restricted, and the piston 5 starts sliding together with the piston rod 6 in the direction of arrow a in the figure.

At this time, the oil in the oil chamber B flows into the oil chamber C through the passage 9 without generating almost any flow resistance. Therefore, during the contraction stroke of the piston rod 6, almost no resistance is generated, and the piston rod 6 can be operated smoothly and quickly. The volume of the piston rod 6 entering the cylinder 1 is compensated for by the free piston 8 being displaced to the right in the figure and the air chamber A being contracted.

On the other hand, when an external force acts on the piston rod 6 in the direction shown by the arrow in the figure, first only the piston rod 6 moves, the piston 5 and the stepped portion 6B are separated, and the stop horn 4'7 comes into contact with the piston 5. If an external force is further applied to the piston rod 6, the piston 5 will be slid along with the piston rod 6 in the direction shown by the arrow in the figure. Therefore, the pressure inside the oil chamber C becomes high, and the oil inside the core oil chamber C flows out to the oil chamber B side through the passage 9 and the orifice 10. Since the orifice 10 has a small flow path area, an extremely large hydraulic resistance force is generated, and a large damping force can be obtained when the piston rod 6 is extended.

FIG. 2 shows the relationship between the hydraulic resistance force and the speed of the piston 5 in the hydraulic shock absorber according to the prior art described above. As is clear from the figure, since the flow area M of the orifice 10 is constant during the extension stroke of the piston rod 6, the characteristics of the pressure resistance force of the oil (6) with respect to the piston speed are constant. Therefore, for example, if it is necessary to generate only a small hydraulic resistance force when the speed of the piston 5 is in a low speed range, but to generate an extremely large hydraulic resistance force in a high speed range, it is necessary to change the hydraulic resistance force characteristics to the speed of the piston 5. It has not been possible to perform control that varies depending on the area using the hydraulic shock absorber according to the prior art described above. That is, the degree of freedom in setting the characteristics of the hydraulic resistance force is limited, and there is a drawback that the characteristics cannot be set optimally depending on the application of the cylinder device.

The present invention eliminates the drawbacks of the prior art described above, and is characterized in that the piston, which is movable in the axial direction of the piston rod, is provided with a passage having a large flow area. An elastic member is provided between the piston and a restriction part that restricts movement in one direction, and an elastic member is formed between the piston and the restriction part, and the elastic member is provided through the passage only when the piston is slidably displaced in one direction. a first hydraulic resistance force generating section that applies a hydraulic resistance force to the flowing oil and is closed by the piston suppressing and deforming the elastic member when the piston reaches a predetermined speed or higher; The characteristics of the hydraulic resistance force are multi-staged by opening and closing the first hydraulic resistance force generation part so as to provide resistance to the oil flowing through the passage even after the first hydraulic resistance force generation part is closed. Hereinafter, a case where the cylinder device of the present invention is used as a hydraulic shock absorber will be explained based on FIGS. 3 to 27.

First, FIGS. 3 to 7 show a first embodiment of the present invention, and the same components as those in FIG. 1 are designated by the same reference numerals and their explanations will be omitted. Also in the present invention, the piston rod 6 forming the piston-piston rod assembly has a small diameter portion 6A formed at its tip, and the piston 21 inserted into the small diameter portion 6A is movable in its axial direction. There is. A restricting portion that restricts the movement range of the piston 21 is comprised of a step portion 6B of the piston rod 6 and a stopper 22 fixed to the tip of the small diameter portion 6A. However, the orifice shown in the prior art is not formed in the strike /422. In addition, a first passage 23 having a large flow path area is bored in the piston 21 so that the oil chamber B and the oil chamber C communicate with each other without generating hydraulic resistance. There is an orifice 24 which has a much smaller flow area than the passage 23 and serves as a second hydraulic resistance force generating section.
is drilled.

Reference numeral 25 denotes a disc spring as an elastic member loosely fitted to the small diameter portion 6A of the piston rod 6 between the end face of the piston 21 facing the oil chamber B and the stopper 22. Two cutouts 26,26 are provided which serve as second passages (see FIG. 7). Furthermore, annular protrusions 21A and 21B are concentrically protruded from the end surface of the piston 21 facing the vicinity of the inner and outer peripheral edges of the disc spring 25, respectively. Then, when the piston 21 is displaced toward the stop/f22 side, the protrusion 21A comes into contact with the disc spring 25, and the protrusion 21A comes into contact with the disc spring 25.
An annular flow path 27 having a spacing t is formed between 1B and the disc spring 25, and the flow path 27 serves as a throttle passage as a first hydraulic resistance force generating section (see FIG. 5). . In addition, the protrusion 21A is activated when the pressure inside the oil chamber C becomes large.
Press 5 to change.

Furthermore, the protrusion 21B has a function of shaping the flow path 27.
It has the function of occluding the

The hydraulic shock absorber according to this embodiment has the above-described configuration, and its operation will be explained next.

First, when an external force acts on the piston rod 6 in the direction of arrow a in FIG. 3, the piston rod 6 starts to contract.

When the stepped portion 6B is brought into contact with the piston 21, the piston 21 is slidably displaced together with the piston rod 6 in the direction of the arrow a, as shown in FIG. This piston 2
Due to the sliding displacement 1, the pressure inside the oil chamber B becomes high, and the oil in the oil chamber B flows into the oil chamber C through the passage 23. Since the flow area of the core passage 23 is large and no flow resistance is generated in the oil flowing in the northern part, no resistance is generated during the contraction stroke of the piston rod 6, and the contraction is performed smoothly and quickly. At this time, the disc spring 25 is connected to the piston 21
However, since the disc spring 25 is provided with a notch 26 that serves as a second passage, there is no problem with the flow of the oil.

On the other hand, when an external force acts on the piston rod 6 in the direction shown by the arrow in FIG. 3, the piston rod 6 is extended. First, the stone jar 22 is brought close to the piston 21, and the spring force of the disc spring 25 disposed between the piston 21 and the stopper 22 causes the protrusion 21A of the piston 21 and the disc spring 25 to The state shown in FIG. 5 is reached in which a flow path 27 that generates a first hydraulic resistance force is formed between them. Therefore, when the piston 21 is further displaced together with the piston rod 6 in the direction shown by the arrow, the pressure inside the oil chamber C becomes high, and the oil inside the oil chamber C flows into the oil chamber B via the orifice 24 and the flow path 27. Inflow. Since a predetermined hydraulic resistance force is generated against the flow of the oil, the piston 21 is decelerated.

When a large external force acts on the piston rod 6 and the piston 21 attempts to slide at high speed, the pressure in the oil chamber C becomes even higher, and the differential pressure with the oil chamber B increases. For this reason, the piston 21 is further pressed toward the piston 22 side, and the stepped portion 21B is displaced in the direction of the disc spring 25.
Further constricting the flow path 27 increases the flow resistance of the oil flowing through the flow path 27, that is, the hydraulic resistance force. Then, when the piston 21 reaches an extremely high speed, the differential pressure between the oil chamber C and the oil chamber B becomes even larger, and the disc spring 25 becomes held between the protrusion 21B of the piston 21 and the stopper 22. , the flow path 27 will be blocked. As a result, the oil flows out only from the orifice 24, so the hydraulic resistance force becomes even greater, and the deceleration of the piston 21 becomes even greater.

Therefore, the relationship between the speed of the piston 21 and the hydraulic resistance force is shown in FIG. As is clear from the figure, in the extension stroke, the flow path area of the piston 21 in the low speed region is smaller than the orifice 2.
4 and the flow path 27 are the sum of the flow path area, so the flow path area is relatively large and the hydraulic resistance is small. Then, when the speed of the piston 21 increases and the differential pressure between the oil chamber C and the oil chamber B exceeds the spring force FA of the disc spring 25, the flow path 27 is closed and the flow path area becomes only the orifice 24. Since then, the characteristics of the hydraulic resistance change, and the deceleration of the piston 21 becomes extremely large. Therefore, the size of the orifice 24, the countersunk 2
By appropriately selecting the shape, spring force, etc. of 5, desired hydraulic resistance characteristics can be obtained.

Next, FIGS. 9 to 13 show a second embodiment of the present invention, in which a hollow rubber ring 31 is used as the elastic member in place of the countersunk shown in the previous embodiment.
is used. The rubber ring 31 has a through hole 32 that penetrates in the radial direction, and a circumferential groove 33 that is formed on the outer peripheral edge of the rubber ring 31 and is continuous with the through hole 32. And the rubber ring 31 is connected to the piston 21 and the piston /4'22
A large number of retainer arms 34, 34 . ..., and the inner peripheral side of the rubber ring 31 and the small diameter portion 6A (13
) A second annular passage 35 is formed between the two.

Even if the hydraulic shock absorber is configured in this way, it has the same effect as the first embodiment described above. That is, when an external force is applied to the piston rod 6 in the direction of arrow a as shown in FIG. Since a large flow path is secured, no flow resistance, that is, hydraulic resistance force is generated in the oil flowing from oil chamber B to oil chamber C via passage 23.35.

On the other hand, when an external force is applied to the piston rod 6 in the direction indicated by the arrow as shown in FIG. Since there is only the orifice 24 and the through hole 32, hydraulic resistance force is generated. Then, as the sliding displacement of the piston 21 becomes high speed and the differential pressure between the oil chamber C and the oil chamber B becomes large, the piston 21 presses the rubber ring 31 and the through hole 32 is closed. The state shown in Figure 11 will be obtained. For this reason,
The only flow path from oil chamber C to oil chamber B is orifice 24 (14
), and the hydraulic resistance becomes extremely large.

Furthermore, FIGS. 14 and 15, FIG. 16 and 1
Figure 7, Figures 18 to 22, Figures 23 to 27
The figures are respectively shown in the third section of the present invention. 4th゜5th. This shows a sixth embodiment, and the basic configuration is the same as that of the first embodiment.

However, in the third embodiment shown in FIGS. 14 and 15, a disc spring 41 shown in FIG. 15 is used as the elastic member. The disc spring 41 is provided with two notches 42, 42 serving as second passages on its inner circumferential side, and one notch 43 on its outer circumferential side. When the disc spring 41 is pressed toward the stock spring f22, a flow spring is formed between the cutout portion 43 and the stock spring 22, which becomes a first hydraulic resistance force generating portion.

Next, in the fourth embodiment shown in FIGS. 16 and 17, a disc spring 51 is used as the elastic member, and a notch 52 is provided on the inner circumference of the disc spring 51 to serve as a second passage. What is installed is shown. The first hydraulic resistance force generating section is a flow path 53 with a distance t' between /f22 and the disc spring 51.
It is formed by υ.

Furthermore, in the fifth embodiment shown in FIGS. 18 to 22, a disk 61 formed in an annular shape is used as the elastic member. A notch 62, which serves as a second passage, is formed in the inner peripheral portion of the disk 61.

On the other hand, the straight horn 963 has a long part 63A with a thicker plate on the inner circumferential side and a short part 63A with a thinner plate on the outer circumferential side.
3B, and the long portion 63A protrudes toward the piston 21 by a distance t with respect to the short portion 63B. Further, four annular portions 63C are formed between the long entry portion 63A and the short portion 63B. Further, the piston 21 has an annular protrusion 21C formed on its outer circumferential side for pushing and deforming the disk 61. When the cutout portion 62 comes into contact with the elongated portion 63A, a flow path 62A is formed (see Fig. 19, 8).
The flow path 62A is configured to serve as an orifice.

In this embodiment, the first hydraulic resistance force generating portion is generated by the notch 62 and the elongated portion 63A when the disc 61 is held between the protrusion 21C of the piston 21 and the elongated portion 63A of the ST2 463. It is the flow path 62A formed, or the flow path 64 formed between the disk 61 and the short portion 63B.

As shown in FIG. 20, when an external force acts on the piston rod 6 and the piston rod 6 is displaced in the direction of the arrow a, the piston 21 and the stepped portion 6B come into contact. At this time, the disk 61 is also displaced toward the stepped portion 6B together with the piston 21, but since the disk 61 has a notch 62 formed therein, the oil in the oil chamber B flows through the notch 62 and the first passage 23. The oil flows into the oil chamber C, and no hydraulic resistance is generated.

However, as shown in Figure 21, screw 7).

When an external force acts on the rad 6 in the direction shown by the arrow, the piston 21
The protruding portion 21C and the elongated portion 63A of the strut horn 963 come into contact with each other, and a flow path 62A is formed in the cutout portion 62. This flow path 6
Since 2A serves as the first hydraulic resistance force generating portion, the deceleration action of the piston 21 is performed (t17).

Then, when a large external force acts on the piston rod 6 and the piston 21 is displaced to the extension side at high speed, the oil chamber C
and the oil chamber B, the protrusion 21 of the piston 21
C connects the outer peripheral edge of the disk 61 to the short portion 63 of the stopper 63.
B side, and the flow path 6 is removed from the flow path 62A and the recess 63C.
Hydraulic resistance increases due to the flow resistance of the oil flowing out into the oil chamber B through the oil chamber B. Then, when the piston 21 is displaced at a higher speed, the first hydraulic resistance force generating section is closed when the disk 61 comes into contact with the short section 63B as shown in FIG. As a result, the oil fluid flows only through the orifice 24, which is the second hydraulic resistance force generating section, and the hydraulic resistance characteristics change rapidly.

In the case of this embodiment, although it has been described that the flow path 62 formed by the notch 62 forms the first hydraulic resistance force generating section, the diameter of the flow path 62A is adjusted so as not to generate hydraulic resistance force. If the diameter of the flow path 62A is made large, the flow path 64 becomes the first hydraulic resistance force generating part, which is the same as the embodiment (18) (1).If the diameter of the flow path 62A is made small, the flow path 62A becomes the first hydraulic resistance force generating part. This will greatly contribute to the generation of hydraulic resistance.

Further, FIGS. 23 to 27 show a sixth embodiment of the present invention, and its basic configuration is not significantly different from the fifth embodiment described above. However, in this embodiment, a disk 71 as shown in FIG. 24 is used as the elastic member.

A hole 72 serving as a second hydraulic resistance force generating section is bored in the disk 71 at a position facing the recess 63C of the stopper 63, but no second passage is formed therein. and,
The disc 71 is in contact with the elongated portion 63A of the horn 463 when the disc 71 is in the stock position. 53 together with the piston rod 6
It is fixedly provided to the small diameter portion 6A of.

Its operation is shown in Figures 25 to 27.
There is nothing particularly different from that shown in the fifth embodiment. However, as shown in FIG. 25, when an external force acts on the piston rod 6 in the direction of arrow a, the piston 21 comes into contact with the stepped portion 6B, but the disk 71 is not displaced. Therefore,
A second passage 73 will be formed between the protrusion 21C and the disc 7.1.

In each of the above-described embodiments, the case where the cylinder device according to the present invention is used as a hydraulic shock absorber has been described, but it goes without saying that it can also be used as a gas spring or the like. Although it has been described above that the hydraulic resistance force is generated in the extension stroke of the piston rod 6, it is not necessarily necessary to provide the hydraulic resistance force in the piston rod 6 in the contraction stroke.

As described in detail above, according to the cylinder device according to the present invention, the piston that is movable in the axial direction of the piston rod is provided with a passage having a large flow area, and the piston and the piston move in one direction. An elastic member is interposed between the piston and the restriction part that restricts movement, and an oil liquid is formed between the piston and the restriction part and flows through the passage only when the piston is slid in one direction. a first hydraulic resistance generating section that applies a hydraulic resistance to the piston, and is closed by the piston suppressing and deforming the elastic member when the piston reaches a predetermined speed or higher; and a second hydraulic resistance force generating part bored in the piston so as to provide a resistance force to the oil flowing through the passage even after the force generating part is closed, so that the hydraulic resistance characteristics of the piston can be adjusted. It can be changed in multiple stages depending on the speed, for example, hydraulic resistance is small in the piston's low-speed range, and large hydraulic resistance is generated in the piston's high-speed range.The desired hydraulic resistance characteristics can be controlled depending on the application of the cylinder device. becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing a hydraulic shock absorber as a cylinder device according to the prior art, FIG. 2 is a diagram showing hydraulic resistance characteristics with respect to piston speed of the hydraulic shock absorber shown in FIG. 1, and FIGS. The figure shows the first embodiment of the present invention.
The figure is a vertical cross-sectional view of a hydraulic shock absorber as a cylinder device.
Figure 6 is a partially enlarged view of Figure 3 showing different operating states, Figure 7 is a fifth external view of the disc spring, and Figure 8 is a line section showing hydraulic resistance characteristics with respect to piston speed. 9 to 13 show a second embodiment of the present invention,
9 to 11 are partial sectional views of the cylinder device showing different operating states, FIG. 12 is an external view showing the assembled state of the rubber ring, and FIG. 13 is a vertical sectional view of the main part of the rubber ring. 14 and 15 show a third embodiment of the present invention, FIG. 14 is a partial sectional view of the cylinder device, and FIG. 15 is a partial sectional view of the cylinder device.
16 and 17 show a fourth embodiment of the present invention, FIG. 16 is a partial sectional view of a cylinder device, FIG. 17 is an external view of a disc spring, and FIG. 18 is a partial sectional view of a cylinder device. 22 to 22 show a fifth embodiment of the present invention, FIG. 18 is a partial sectional view of a cylinder device, FIG. 19 is an external view of a countersunk spring, and FIGS. 20 to 22 show different operations. 23 to 27 show the sixth embodiment of the present invention, and FIG. 23 is a partial sectional view of the cylinder device,
FIG. 24 is an external view of the disc spring, and FIGS. 25 to 27 are operation explanatory views showing different operating states. 1...Cylinder, 6...Piston rod, 6A...
・Small diameter part, 6B... Step part, 21... Piston, 22
...stopper, 23...first passage, 26.42.
52゜62... Notch, 24... Orifice, 25
, 41° 51... Belleville spring, 27, 62A... Channel,
31...Rubber ring, 32...Through hole, 35...
2nd passage, 43...notch, 61.71...disc, 72...hole XBIC...oil chamber (23) Figure 1 Figure 2 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 18 Figure 19 Figure 23 Figure 24 Figure 26 Figure 27 Procedural amendment (voluntary) June 10, 1981 Patent Application No. 60234 2, Invention Name Cylinder device 3, Relationship to the person making the amendment Patent applicant address 1-6-8-4 Fujimi, Yozaki-ku, Yozaki-shi, Kanagawa Prefecture
, Agent 〒160 5, Date of amendment order 6 Number of inventions increased by amendment 7, Subject of amendment (1) There is no need to include the content of the amendment in column 8 of "Detailed Description of the Invention" of the specification. Furthermore, the orifice 24 is connected to the piston 2
In the above description, the piston 21 is diagonally branched from the first passage 23 of the piston 21, but instead of the orifice 24, an orifice or a cutout groove may be provided in the annular projection 21C of the piston 21 in the radial direction. These may be used as the second hydraulic resistance force generating section. ” he corrected.

Claims (5)

[Claims] (1) A cylinder filled with oil and gas, a piston rod with one end located inside the cylinder and the other end protruding outside the cylinder, and a piston rod inserted into one end of the piston rod so as to be movable in the axial direction. , a piston that defines two oil chambers within the cylinder; a passage with a large flow area formed in the piston so as to communicate the inner oil chamber; a pair of restriction parts that restrict a movement range; an elastic member provided between one of the restriction parts and the piston; and an elastic member provided between or between the elastic member and the piston. It is formed between an elastic member and one regulating part, and applies hydraulic resistance to the oil flowing through the passage only when the piston moves in one direction, and when the piston reaches a predetermined speed or higher. a first hydraulic resistance force generation section that is closed by the piston suppressing and deforming the elastic member; and a resistance force against the oil fluid flowing through the passageway even after the first hydraulic resistance force generation section is closed. a second hydraulic resistance force generating section bored in the piston so as to provide a second hydraulic resistance force generating section. (2) Claim (1) wherein the first hydraulic resistance force generating section is a fixed throttle passage formed in the elastic member or a variable throttle passage whose flow path area decreases according to deformation of the elastic member. Cylinder device described in section. (3) Claim (1) wherein the elastic member is a disc spring.
) Cylinder device described in section 2. (4) The cylinder device according to claim (1), wherein the elastic member is a disk formed in a circular R shape. (5) The cylinder device according to claim (1), wherein the elastic member is a rubber ring formed in an annular shape.