JP3953669B2 - Hydraulic shock absorber - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic shock absorber, and more particularly to an improvement of a multistage hydraulic shock absorber.
[0002]
[Prior art]
Since a multistage hydraulic shock absorber can have a smaller mounting length than a standard hydraulic shock absorber, for example, when used as a rear shock absorber in a four-wheel vehicle, the rear floor surface in the vehicle Further, there is an advantage that the upper end of the shock absorber is not protruded, that is, the rear floor surface in the vehicle can be set wide by making it flat in the left-right direction.
[0003]
By the way, in principle, the multistage hydraulic shock absorber is formed in a so-called double cylinder type cylinder body 1 connected to the axle side of the vehicle, as shown in FIG. It is assumed that the first-stage piston rod 2 is inserted so as to be able to appear and retract under the intervention of the piston 3.
[0004]
The first-stage piston rod 2 is a so-called second-stage cylinder body, and the so-called second-stage piston rod 4 connected to the vehicle body side in the first-stage piston rod 2 is interposed in the piston 5. It is said that it is inserted so that it can appear below.
[0005]
The first-stage piston rod 2 has an upper oil chamber R1 and a lower oil chamber R2 that are partitioned by the piston 5 and can communicate with each other via a damping valve 5a disposed in the piston 5. It is supposed to become.
[0006]
Further, the inner cylinder 6 constituting the cylinder body 1 has a rod-side oil chamber R3 and a piston-side oil chamber R4 defined by the piston 3, and the lower oil chamber R2 is connected to the piston rod 2 as described above. The cylinder body together with the inner cylinder 6 is communicated with the rod-side oil chamber R3 through the passage 2a formed in the inner cylinder 6 and the piston-side oil chamber R4 is disposed inside the lower end of the inner cylinder 6. 1 communicates with a reservoir chamber R defined between the outer cylinder 7 and the outer cylinder 7.
[0007]
Therefore, in the hydraulic shock absorber described above, the upper oil chamber R1, the lower oil chamber R2, and the rod side oil chamber R3 are oils that are blocked from the piston side oil chamber R4 and the reservoir chamber R by the arrangement of the piston 3. A room space is formed.
[0008]
Further, in the hydraulic shock absorber described above, the cross-sectional area S1 and the rod-side cross-sectional area S2 of the oil chamber R3 of the piston rod 4 is set to be substantially identical.
[0009]
Therefore, in this hydraulic shock absorber, when the piston rod 4 is projected and retracted with respect to the piston rod 2 that is the second-stage cylinder body, a predetermined damping force is provided by the damping valve 5 a disposed on the piston 5. Is generated, and in the rod side oil chamber R3, an inflow and outflow of an amount of oil corresponding to the intrusion volume integral and the withdrawal volume integral of the piston rod 4 is expressed.
[0010]
As a result, the piston rod 2 itself is projected and retracted with respect to the cylinder body 1, that is, with respect to the inner cylinder 6 constituting the cylinder body 1, and therefore, between the piston-side oil chamber R 4 and the reservoir chamber R. A predetermined damping force is also generated by the damping valve 6a disposed in the.
[0011]
From the above, in the hydraulic shock absorber according to this conventional example, when the piston rod 4 is projected and retracted with respect to the piston rod 2, the piston rod 2 is also retracted with respect to the cylinder body 1. Therefore, the damping force as set can be generated by the damping valves 5a and 6a under the so-called smooth expansion and contraction operation.
[0012]
[Problems to be solved by the invention]
However, in the hydraulic shock absorber mounted on the vehicle, it is obvious that the temperature of the oil accommodated therein rises due to the continuous expansion and contraction operation. Therefore, even in the conventional hydraulic shock absorber described above, It is natural that the temperature of the oil contained inside rises due to the continuous expansion and contraction operation.
[0013]
At this time, in the hydraulic shock absorber, the piston side oil chamber R4 defined by the distribution of the piston 3 communicates with the reservoir chamber R. Therefore, the oil temperature in the piston side oil chamber R4 is increased. The volume expansion is absorbed by the reservoir chamber R and basically has no effect.
[0014]
On the other hand, in the upper oil chamber R1, the lower oil chamber R2, and the rod side oil chamber R3 which are oil chamber spaces that are partitioned and closed by the arrangement of the piston 3, the oil temperature here rises. There is no other way but to absorb the volume expansion by the lowering of the piston 3, that is, the piston side oil chamber R4.
[0015]
As a result, the amount of protrusion / disengagement of the piston rod 2 with respect to the amount of protrusion / disengagement of the piston rod 4 is different before and after the rise of the oil temperature, and also differs depending on the rise of the oil temperature. Therefore, the effective stroke amount of the piston rod 2 is insufficient.
[0016]
When the effective stroke amount of the piston rod 2 is insufficient, a so-called mechanical hit such as the piston 3 continuously connected to the piston rod 2 hits the lower end of the inner cylinder 6 is developed. When the cracking pressure of the damping valve 6a is set high in order to avoid hitting, the riding comfort in the vehicle is deteriorated.
[0017]
The present invention was devised in view of the above-described circumstances, and the object of the present invention is to reduce the effective stroke amount of the piston rod even if the oil temperature rises due to continued expansion and contraction operation. For example, to provide a multistage hydraulic shock absorber that is optimally used as a rear shock absorber in a four-wheel vehicle.
[0018]
[Means for Solving the Problems]
In order to achieve the above-described object, the hydraulic shock absorber according to the present invention basically has a structure in which a first-stage piston rod, which is a second-stage cylinder body, is placed in the first-stage cylinder body under the piston. The second stage piston rod is inserted into the first stage piston rod so as to be able to move in and out, and is connected to the second stage piston rod in the first stage piston rod. The upper oil chamber and the lower oil chamber which are partitioned by a provided piston and communicated with each other via a damping valve disposed in the piston are provided, and the first stage is provided in the inner cylinder constituting the first stage cylinder body. Hollow piston rod will have a rod-side oil chamber partitioned by the piston of the continuously arranged and the piston side oil chamber, said lower oil chamber through a passage formed in the first stage of the piston rod of the Communicates with the de-side oil chamber is defined between the outer cylinder constituting the cylinder body of the first stage together with the inner cylinder through the damping valve of Haizai the lower end inside the inner tube above the piston side oil chamber The upper oil chamber, the lower oil chamber, and the rod-side oil chamber are connected to the reservoir chamber to form an oil chamber space that is blocked from the piston-side oil chamber and the reservoir chamber by the piston connected to the first-stage piston rod. In addition, the hydraulic shock absorber is configured so that the cross-sectional area of the second-stage piston rod and the cross-sectional area of the rod-side oil chamber are substantially the same, and the oil chamber space is formed in the first-stage piston rod. This is connected to an oil temperature compensation mechanism disposed in the piston-side oil chamber through an orifice formed in a continuous piston, and the oil temperature compensation mechanism has the same volume as the oil chamber space. An oil temperature compensation chamber communicating with the chamber, and the above Has a front chamber communicating with the orifice, and the pre-chamber and the temperature compensation piston while defining an oil temperature compensating chamber in accordance with the oil temperature change is wide or narrow and the front chamber and the oil temperature compensating chamber at the same time, the temperature compensation It is assumed that the cross-sectional area S3 in the front chamber R7 of the piston P and the cross-sectional area S4 in the oil temperature compensation chamber R6 are set to be the same .
[0019]
DETAILED DESCRIPTION OF THE INVENTION
In the following, the present invention will be described based on the illustrated embodiment. However, even in the hydraulic shock absorber according to the present invention, in principle, the configuration is the same as that of the conventional hydraulic shock absorber shown in FIG. Has been.
[0020]
Therefore, in the illustrated embodiment, where the configuration is the same as that of the hydraulic shock absorber shown in FIG. 3, the detailed description will be made only with the same reference numerals in the drawing except where necessary. In the following, the description will focus on the features of the present invention.
[0021]
That is, in the hydraulic shock absorber according to the present invention, as shown in FIG. 1, the closed oil chamber space including the upper oil chamber R1, the lower oil chamber R2, and the rod-side oil chamber R3 is a second-stage cylinder body. It is assumed that the oil temperature compensation mechanism S arranged in the piston-side oil chamber R3 is communicated with the piston 3 through the orifice 3a formed in the piston 3 connected to the first-stage piston rod 2.
[0022]
Then, as shown in FIG. 2, the oil temperature compensation mechanism S includes a container chamber R5 having the same volume as the oil chamber space, an oil temperature compensation chamber R6 communicating with the container chamber R5, and the orifice 3a. There is a front chamber R7 that communicates, and an oil temperature compensation piston P that partitions the front chamber R7 and the oil temperature compensation chamber R6 and simultaneously widens and narrows the front chamber R7 and the oil temperature compensation chamber R6 according to changes in the oil temperature. The sectional area S3 in the front chamber R7 of the oil temperature compensation piston P and the sectional area S4 in the oil temperature compensation chamber R6 are set to be the same.
[0023]
Incidentally, in the illustrated embodiment, the oil temperature compensation mechanism S is held on the lower end surface of the piston 3 connected to the first-stage piston rod 2, and the oil temperature compensation mechanism S is The temperature compensating piston P to be configured is movable in a direction in which the first-stage piston rod 2 and the second-stage piston rod 4 slide, that is, in a direction orthogonal to the expansion / contraction direction of the hydraulic shock absorber. Yes.
[0024]
Since the oil temperature compensation mechanism S is held by the piston 3, it is not necessary to dispose this kind of oil temperature compensation mechanism outside the hydraulic shock absorber. Therefore, when the hydraulic shock absorber is mounted on a vehicle, This is advantageous in that the in-vehicle performance is not deteriorated.
[0025]
In addition, since the temperature compensation piston P constituting the oil temperature compensation mechanism S can be moved in a direction orthogonal to the expansion / contraction direction of the hydraulic shock absorber, the substantial expansion / contraction stroke of the hydraulic shock absorber is greatly reduced. This is advantageous in that it does not invite
[0026]
Therefore, in the hydraulic shock absorber according to the present invention configured as described above, when the oil temperature rises due to the continuing expansion and contraction operation, the upper oil chamber R1, the lower oil chamber R2, and the rod side oil chamber. volume expansion induced in the oil chamber space of R3 is to be induced also in vessel chamber R5 of the same volume and the oil chamber space.
[0027]
Then, the oil corresponding to the expansion caused by the volume expansion induced in the oil chamber space flows into the front chamber R7 through the orifice 3a, and the oil corresponding to the expansion caused by the volume expansion induced in the container chamber R5 is oil. It will flow into the temperature compensation chamber R6.
[0028]
At this time, the cross-sectional area of the temperature compensation piston P that partitions the front chamber R7 and the oil temperature compensation chamber R6, that is, the cross-sectional area of the temperature compensation piston P that partitions the front chamber R7 and the temperature compensation that partitions the oil temperature compensation chamber R6. Since the cross-sectional areas of the pistons P are set to be the same, the oil amount is not changed in the oil chamber space.
[0029]
Therefore, when the second-stage piston rod 4 is projected and retracted with respect to the first-stage piston rod 2 that is the second-stage cylinder body, the first-stage piston rod 2 with respect to the cylinder body 1 is also As a result, the damping force by the damping valves 5a and 6a is generated as set.
[0030]
By the way, the above-described orifice 3a causes the expansion when the oil temperature in the oil chamber space rises to flow into the front chamber R7, and the oil in the front chamber R7 is allowed to flow out when the oil temperature decreases after the dredging. It functions to return to the space, and when the second-stage piston rod 4 moves in and out with respect to the first-stage piston rod 2, that is, when the hydraulic shock absorber performs normal expansion and contraction, It functions to block the passage of oil.
[0031]
Therefore, at the time of so-called expansion / contraction operation, the presence of the orifice 3a does not cause so-called oil leakage, and it does not mean that normal expansion / contraction operation is not hindered.
[0032]
【The invention's effect】
As described above, according to the present invention, the first-stage piston rod, which is the second-stage cylinder body, is inserted into the first-stage cylinder body so as to be able to protrude and retract, and the first-stage piston rod is inserted into the second-stage piston rod. the eye of the piston rod is inserted to retractably, so to speak closed oil chamber space stage consists of a row of upper oil chamber partitioned into a piston inside the rod and the lower oil chamber and the rod side oil chamber partitioned in the cylinder body The cylinder is connected to an oil temperature compensation mechanism disposed in a piston-side oil chamber through an orifice formed in a piston connected to the piston rod, and the oil temperature compensation mechanism is connected to the oil chamber space. A volume chamber having the same volume, an oil temperature compensation chamber communicating with the volume chamber, a front chamber communicating with the orifice, and the front chamber and the oil temperature compensation chamber are simultaneously defined according to changes in the oil temperature. Wide temperature Since the cross-sectional area of the temperature compensation piston in the front chamber and the cross-sectional area of the oil temperature compensation chamber are set to be the same, the volume expansion induced in the oil chamber space is caused by the oil chamber. It is also induced in a volume chamber having the same volume as the space, and the volume of oil induced by the volume expansion induced in the oil chamber space flows into the front chamber through the orifice, and the volume induced in the volume chamber. The oil corresponding to the expansion due to the expansion flows into the oil temperature compensation chamber, and at this time, the cross-sectional area of the temperature compensation piston that divides the front chamber and the oil temperature compensation chamber is set to be the same. Therefore, when the second-stage piston rod appears and retracts with the set expansion / contraction stroke with respect to the first-stage piston rod, which is the second-stage cylinder body, the amount is not changed. That the first stage of the piston rod also will be infested with telescopic stroke configuration. As a result, the damping force generated by the damping valve is generated in the set manner.
[0033]
If the oil temperature compensation mechanism is held on the lower end surface of the piston connected to the first-stage piston rod, this type of oil temperature compensation mechanism need not be arranged outside the hydraulic shock absorber. Therefore, it is advantageous in that the in-vehicle performance when the hydraulic shock absorber is mounted on the vehicle is not deteriorated.
[0034]
Further, when the temperature compensation piston constituting the oil temperature compensation mechanism is movable in the direction perpendicular to the expansion / contraction direction of the hydraulic shock absorber, the substantial expansion / contraction stroke of the hydraulic shock absorber is greatly reduced. This is advantageous in that it does not cause defects.
[0035]
As a result, according to the present invention, even if the oil temperature rises due to continued expansion and contraction operation, for example, as a rear shock absorber in a four-wheel vehicle, without reducing the effective stroke amount of the piston rod. It will be optimal.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view showing in principle a hydraulic shock absorber according to the present invention.
FIG. 2 is an enlarged schematic longitudinal sectional view showing an oil temperature compensation mechanism.
FIG. 3 is a view showing a hydraulic shock absorber as a conventional example in the same manner as FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylinder body 2 The 1st-stage piston rod used as the 2nd-stage cylinder body 2a Passage 3, 5 Piston 3a Orifice 4 2nd-stage piston rod 5a, 6a Damping valve 6 Inner cylinder which comprises a cylinder body 7 Cylinder body Constructing outer cylinder G Gas chamber O Oil level P Oil temperature compensating piston R Reservoir chamber R1 Upper oil chamber R2 Lower oil chamber R3 Rod side oil chamber R4 Piston side oil chamber R5 Container chamber R6 Oil temperature compensation chamber R7 Front chamber S Oil temperature Compensation mechanism
S1, S2, S3, S4 cross section

Claims (1)

A first-stage piston rod 2 , which is a second-stage cylinder body, is inserted into the first-stage cylinder body 1 so as to be able to protrude and retract under the intervention of the piston 3 , and the second-stage piston rod 2 is inserted into the first-stage piston rod 2 . the piston rod 4 is being inserted into retractably under intervention of the piston 5, Haizai to the piston 5 is partitioned into the second stage of the piston rod 4 in the first stage of the piston rod within 2 by the piston 5 continuously provided It has an upper oil chamber R1 and a lower oil chamber R2 that can communicate with each other via the damping valve 5a , and is connected to the first-stage piston rod 2 in the inner cylinder 6 that constitutes the first-stage cylinder body 1 . the piston 3 will have a rod-side oil chamber R3 and the piston side oil chamber R4 which is defined by said rod-side oil above the lower oil chamber R2 via the passage 2a of forming the piston rod 2 of the first stage with the chamber R3 Defined between the with an outer cylinder 7 constituting the cylinder body 1 of the first stage together with the inner cylinder 6 via the damping valve 6a of Haizai the lower end inside the above-mentioned piston-side oil chamber R4 inner cylinder 6 it communicates with the reservoir chamber R, and the piston-side oil chamber R4 and the reservoir chamber R by the piston 3 of the continuously provided above the upper oil chamber R1 and the lower oil chamber R2 and the rod side oil chamber R3 into the piston rod 2 of the first stage to form a blocked oil chamber space, in the hydraulic shock absorber sectional area S1 and the rod-side cross-sectional area S2 of the oil chamber R3 of the second stage of the piston rod 4 is set to be approximately the same, The oil chamber space is communicated with the oil temperature compensation mechanism S disposed in the piston-side oil chamber R4 via an orifice 3a formed in the piston 3 connected to the first-stage piston rod 2 to compensate for the oil temperature. mechanism S is the same as the above oil chamber space A vessel chamber R5 of the product, an oil temperature compensating chamber R6 communicating with the volume chamber R5, a front chamber R7 communicating with the orifice 3a, the oil temperature while partitioning the front chamber R7 and oil temperature compensating chamber R6 A temperature compensation piston P that simultaneously widens and narrows the front chamber R7 and the oil temperature compensation chamber R6 according to changes, and a sectional area S3 in the front chamber R7 and a sectional area in the oil temperature compensation chamber R6 of the temperature compensation piston P. A hydraulic shock absorber characterized in that S4 is set to be the same.

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