JP4155371B2 - Hydraulic shock absorber - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic shock absorber for a vehicle, and more particularly to an improvement of a hydraulic shock absorber used as a rear cushion unit in a motorcycle.
[0002]
[Prior art]
The hydraulic shock absorber, which is a rear cushion unit in a motorcycle, is preferably set so that the generated damping force can be adjusted according to the road surface condition on which the motorcycle travels.
[0003]
In other words, when a motorcycle under the riding stationary state where the rider is on the vehicle travels on a good road, the generated damping force is lowered to keep the ride comfort, while when traveling on a bad road, the generated damping force is maintained. It is preferable to set so as to suppress large sinking and jumping of the vehicle body.
[0004]
Therefore, various hydraulic shock absorbers that can reduce the generated damping force during the expansion and contraction operation in the vicinity of the stationary state of the ride have been proposed. Among them, the structure of the damping force generation unit is not complicated, and the desired structure is achieved. For example, there is a proposal of a hydraulic shock absorber having a structure as shown in FIG.
[0005]
That is, the hydraulic shock absorber according to the conventional example is configured such that an upper oil chamber R1 and a lower oil chamber R2 defined by a piston 2 that is slidable in a cylinder 1 are bypassed in the vicinity of the stationary state of the vehicle. It is communicating with L.
[0006]
The bypass path L is composed of a concave groove 11 formed in the inner periphery of the cylinder 1, and the concave groove 11 slides in the axial direction of the cylinder 1 and in the vicinity of the stationary state of the ride. The piston 2 is set to have a length that cannot deviate.
[0007]
Incidentally, the piston 2 is held on the piston rod 3 to be inserted to retractably into the cylinder 1, which have a extension side damping valve 21 and the compression side damping valve 22.
[0008]
Therefore, when the hydraulic shock absorber expands and contracts operate under near riding a stationary state, the upper oil chamber R1 and the lower oil chamber R2 are communicated via the bypass passage L, insofar, the extension side damping valve 21 and since the compression side damping valve 22 can not function, the generated damping force in the hydraulic shock absorber is lowered, ride comfort can be maintained satisfactorily.
[0009]
And when this hydraulic shock absorber extends and contracts beyond the vicinity of the boarding stationary state, the piston 2 deviates from the bypass path L, and therefore the bypass path L is not used, and the upper oil chamber R1 and the lower oil chamber R2 is communicated via the extension side damping valve 21 and the compression side damping valve 22, in comparison under riding a stationary state near described above, the generated damping force in the hydraulic shock absorber is high, and jump sinking body of large blocking and that obtained.
[0010]
[Problems to be solved by the invention]
However, in the above-described hydraulic shock absorber, the piston ring 23 interposed on the outer periphery of the piston 2 is in sliding contact with the inner periphery of the cylinder 1 during expansion / contraction operation near the stationary state of the ride. In other words, the concave groove 11 formed on the inner periphery of 1 is also in sliding contact.
[0011]
As a result, when the motorcycle continues running on a good road for a long period of time, the piston ring 23 exhibits uneven wear or abnormal wear due to the presence of the concave groove 11. There is a fear that the damping force generated when the road L is not used does not become as set.
[0012]
In addition, when the concave groove 11 is formed on the inner periphery of the cylinder 1, it is not only required to select a method that does not adversely affect the piston rig 23 such as the generation of burrs, but also the concave groove described above. Considering that the groove 11 is formed on the inner periphery of the cylinder 1, there is a disadvantage that a very precise work is required at the time of processing.
[0013]
The present invention was devised in view of the above-described circumstances, and the object of the invention is to make it possible to reduce the generated damping force during expansion / contraction operation in the vicinity of the stationary state of the ride so that the processing work is not mischievous. It is a matter of course to provide a hydraulic shock absorber capable of greatly reducing the adverse effects on the piston ring, as well as requiring no labor.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, the means of the present invention includes a cylinder, a piston rod inserted into the cylinder so as to be able to project and retract, an upper oil chamber and a lower oil chamber defined by the piston in the cylinder, A damping valve provided on the piston, and a bypass passage that lowers the damping force by communicating the upper oil chamber and the lower oil chamber while bypassing the damping valve when the piston rod extends and retracts in the vicinity of the stationary state of the ride. In the hydraulic shock absorber, the bypass path is configured by a recess formed along the axial direction on the outer periphery of the cylinder, and a pair of upper and lower holes communicating with the upper oil chamber and the lower oil chamber, respectively. a step portion formed in the peripheral lower portion of the cylinder to a locking portion formed at the lower end of the concave portion is engaging with press-fitting the cylindrical body covering the recess and comprising.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a hydraulic shock absorber according to an embodiment of the present invention shown in FIG. 1 will be described. In addition, in order to help understanding of the present invention, the hydraulic shock absorber of the reference example shown in FIGS. 2 and 3 will be described. the hydraulic shock absorber shown in FIG. 1, as well as the hydraulic shock absorber as a conventional example shown in FIG. 4 described above, the cylinder 1, a piston rod 3 inserted retractable freely through the piston 2 in the cylinder 1, cylinder 1 The upper oil chamber R1 and the lower oil chamber R2 defined by the piston 2 therein, the expansion side and pressure side damping valves 21 and 22 provided in the piston 2, and the above-mentioned when the piston rod 3 extends and contracts in the vicinity of the stationary state of the ride A bypass path L is provided that lowers the damping force by communicating the upper oil chamber R1 and the lower oil chamber R2 while bypassing the damping valves 21 and 22.
[0016]
In the present invention, a recess 14 in which the bypass path L is formed on the outer periphery of the cylinder 1 along the axial direction, and a pair of upper and lower holes 12 that respectively connect the recess 14 to the upper oil chamber R1 and the lower oil chamber R2 . 13 and further press-fitting the cylindrical body 4 covering the concave portion 14 to the outer periphery of the cylinder 1 and a stepped portion formed on the lower inner periphery of the cylindrical body 4 in the locking portion 15 formed at the lower end of the concave portion 14. 41 is locked.
[0017]
Therefore, the place where that configuration to be similar to the hydraulic shock absorber as a conventional example described above is, as only referring to the figures in the drawing, Except the case required, the description is omitted, the following The features of the present invention will be mainly described.
[0018]
That is, first, in the embodiment shown in FIG. 1, upper and lower holes 12 and 13 through which the bypass L is opened in the cylinder 1, a recess 14 that communicates with the upper and lower holes 12 and 13, and the recess 14 are provided. It is formed with the cylinder 4 to conceal.
[0019]
The upper and lower holes 12 and 13 are located near the stationary state in which the rider is mounted on the motorcycle that mounts the hydraulic shock absorber, and when the motorcycle travels on a good road, piston 2 which slides are positioned is to have an interval in the axial direction of the cylinder 1 that will not interfere with the 1.
[0020]
The upper and lower holes 12 and 13 prevent the piston 2 from interfering with the hydraulic shock absorber when the motorcycle runs on a rough road and extends and contracts beyond the vicinity of the riding stationary state. the piston 2 is set to deviate from between the upper and lower holes 12 and 13.
[0021]
The recess 14 is formed on the outer peripheral side of the cylinder 1 so as to communicate the upper and lower holes 12 and 13, and is formed in a cylindrical shape surrounding the outer periphery of the cylinder 1 in the illustrated embodiment.
[0022]
Incidentally, the recess 14, instead of being formed into a cylindrical shape, although not shown, the conventional example described above as well as may be formed in a groove shape, in this case, so-called machining area is small because become, there is an advantage in that Habukeru the so-called labor at the time of processing.
[0023]
The cylindrical body 4 is press-fitted into the outer periphery of the cylinder 1 so as to conceal the concave portion 14, and the stepped portion 41 formed on the inner periphery of the lower end portion corresponds to this when pressed from above the cylinder 1. Further, it is fixed at a predetermined position by being locked by a locking portion 15 formed in a stepped shape on the outer periphery of the cylinder 1.
[0024]
Incidentally, since the cylinder 4 is press-fitted into a state in which the cylinder 4 is locked to the outer periphery of the cylinder 1, the thickness of the cylinder 1 in the portion where the cylinder 4 is adjacent is the thickness of the cylinder 1 in the portion where the lower cylinder 4 is not adjacent. Although thinner than the thickness, the mechanical strength because the cylindrical body 4 is adjacent to axial forces in the cylinder 1 is not lowered.
[0025]
Therefore, in the case of the hydraulic shock absorber in this embodiment, the piston ring 23 interposed on the outer periphery of the piston 2 that slides in the cylinder 1 is on a good road on the motorcycle under the stationary state. unless the is His presence between holes 12 and 13 as the upper and lower perforated in the cylinder 1.
[0026]
As a result, if conventional hydraulic shock absorber, in the above case, for although the piston ring 23 is in contact at all times the groove 11, in the case of this invention, the contact even above and below the holes 12 and 13 without not give lead to partial wear and abnormal wear on the piston ring 23.
[0027]
Incidentally, when the hydraulic shock absorber exceeds the vicinity of the boarding stationary state, the piston ring 23 passes through the hole 12 or 13 and deviates from between the upper and lower holes 12 and 13, but the piston ring 23 has the hole 12 or 13. a so to speak a moment to pass, uneven wear and abnormal wear of the piston ring 23 is not threatened by the passage of the holes 12 and 13.
[0028]
By the way , in the hydraulic shock absorber of the reference example shown in FIG. 2, the bypass path L is formed on the outer periphery of the cylinder 1 so as to conceal the upper and lower holes 12 and 13 that are opened in the cylinder 1 and the upper and lower holes 12 and 13. a tubular member 4 to be press-fitted, are formed in the cylindrical body inner circumferential upper and lower holes 12 and 13 are formed on the 4 and recess 42 communicating.
[0029]
That is, in the hydraulic shock absorber according to an embodiment of the present invention shown in FIG. 1 described above, although the outer periphery to the formation of side annular recess 14 of the cylinder 1 is communicating holes 12 and 13 of the perforated in the cylinder 1, this In the reference example , a recess 42 that communicates the holes 12 and 13 is formed on the inner peripheral side of the cylindrical body 4.
[0030]
Then, the recess 42 is, in Reference Example shown, are formed in a cylindrical shape, as in the case of the recess 14 in the described embodiment, may be formed in a groove shape.
[0031]
Incidentally, in this reference example as well, the cylinder 4 is press-fitted into the outer periphery of the cylinder 1 from above the cylinder 1, but the step 41 (see FIG. 1) is not formed on the inner periphery of the lower end, and the lower end is directly It is locked to the locking portion 15 of the formed on the outer periphery of the cylinder 1, and is fixed to a predetermined position.
[0032]
Therefore, in the case of this reference example, since the concave portion 42 communicating the upper and lower holes 12 and 13 is formed on the cylindrical body 4 side, the shaft of the cylinder 1 is compared with the embodiment shown in FIG. This is advantageous in that the mechanical strength against the directional force can be increased.
[0033]
The reference example shown in FIG. 2 and the embodiment shown in FIG. 1 are embodied in a so-called double cylinder type hydraulic shock absorber having an outer cylinder 5 (see FIG. 1) on the outer periphery of the cylinder 1. However, there is an advantage that the cylindrical body 4 is not exposed to the outside.
[0034]
Next, in the reference example shown in FIG. 3, the bypass path L is formed in the thick portion 16 formed integrally on the outer peripheral side of the cylinder 1, the passage amount of oil in the bypass passage L in the thick portion 16 and have a regulating valve V to adjust.
[0035]
Therefore, this reference example is preferably embodied as a single cylinder type hydraulic shock absorber that does not have the outer cylinder 5 (see FIG. 1) on the outer periphery of the cylinder 1.
[0036]
By the way, the bypass path L formed in the thick part 16 is in the thick part 16, and the upper and lower horizontal holes 16 a and 16 b opened in the radial direction of the cylinder 1 and the upper and lower horizontal holes. It consists of a vertical hole 16c opened in the axial direction of the cylinder 1 so as to communicate with 16a and 16b.
[0037]
At this time, the base end of the upper horizontal hole 16 a opens to the upper oil chamber R 1 in the cylinder 1, and the base end of the lower horizontal hole 16 b opens to the lower oil chamber R 2 in the cylinder 1.
[0038]
The regulating valve V is is accommodated in the transverse hole 16a formed so as to expanded the the Yoshitsu portion above (not Shimese marks), to be rotatable interposed under the detent structure D, the orifice O having different diameters during turning operation selectively by aiming the longitudinal hole 16c, which enables the adjustment of the flow rate through the hydraulic oil in the bypass passage L.
[0039]
In the hydraulic shock absorber according to the present invention configured as described above and the hydraulic shock absorber of the reference example, when the motorcycle under the riding stationary state travels on a good road, the piston 2 is in the cylinder 1. slides between the upper and lower holes 12 and 13.
[0040]
As a result, the piston ring 23 interposed on the outer periphery of the piston 2 slides on the inner periphery of the cylinder 1 that is not deformed so as to form a groove. uneven wear and abnormal wear is not incurred due to that there is such.
[0041]
Incidentally, at this time, since the upper oil chamber R1 and the lower oil chamber R2 in the cylinder 1 are in communication with each other by the bypass L, the damping force generated by the hydraulic shock absorber is reduced.
[0042]
When the hydraulic shock absorber expands and contracts beyond the vicinity of the riding stationary state, the piston ring 23 passes through the holes 12 (16a) or 13 (16b) and the upper and lower holes 12, 13 (16a, 16b). However , at this time, the piston ring 23 passes through the hole 12 (16a) or 13 (16b) for a moment, because it passes through the hole 12, 13 (16a, 16b). uneven wear and abnormal wear of the piston ring 23 is not threatened.
[0043]
As described above, the bypass path L is located at the center of the piston stroke in the hydraulic shock absorber, but depending on the use of the hydraulic shock absorber, it is assumed that it is between the stroke that is compressed from the most extended state to the vicinity of the riding stationary state. Of course, in this case as well, the bypass L functions similarly.
[0044]
【The invention's effect】
As described above , according to the present invention, the bypass path is constituted by the concave portion formed in the outer periphery of the cylinder along the axial direction, and the pair of upper and lower holes that respectively connect the concave portion to the upper oil chamber and the lower oil chamber. Therefore, even if the piston slides in the vicinity of the stationary state, the piston ring provided on the outer periphery of the piston does not interfere with the concave portion, and the piston ring can be prevented from being flatly worn or abnormally worn.
[0045]
And since the level | step-difference part formed in the cylinder lower part inner periphery was made to latch to the latching | locking part formed in the lower end of a recessed part, the said cylinder can be fixed in a predetermined position.
[0046]
In addition, since a so-called flow path composed of recesses constituting the bypass path is formed on the so-called outer peripheral side of the cylinder, it is easier to form compared to the case where this flow path is formed on the inner peripheral side of the cylinder. This eliminates the need for mischievous work.
[0047]
Further, when the bypass path is formed by upper and lower holes opened in the cylinder, a recess formed on the outer periphery of the cylinder so as to communicate with the upper and lower holes, and a cylindrical body press-fitted on the outer periphery of the cylinder. , since not exposed to be have a cylindrical body on the outer periphery of the cylinder, an optimum for embodying the hydraulic shock absorber set to a so-called twin-tube type having an outer tube to the outer periphery of the cylinder.
[0048]
Further, when the recess is formed on the outer periphery of the cylinder , the recess can be continuously formed on the upper and lower hole processing lines, and there is an advantage that a plurality of processing lines can be omitted.
[Brief description of the drawings]
FIG. 1 is a partial longitudinal sectional view showing a hydraulic shock absorber according to an embodiment of the present invention.
FIG. 2 is a partial longitudinal sectional view showing a bypass path portion in a hydraulic shock absorber according to a reference example .
FIG. 3 is a view showing a hydraulic shock absorber according to another reference example in the same manner as FIG. 1;
4 is a diagram showing as in FIG hydraulic shock absorber of the conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston 3 Piston rod 4 Cylindrical body 5 Outer cylinder 12,13 Hole 14 Recessed part 15 Locking part 16 Thick part 16a, 16b Horizontal hole 16c Vertical hole 21 Extension side damping valve 22 Pressure side damping valve 23 Piston ring 41 Step part L Bypass R1 Upper oil chamber R2 Lower oil chamber

Claims (1)

A cylinder, a piston rod inserted into and retracted via a piston in the cylinder, an upper oil chamber and a lower oil chamber partitioned by the piston in the cylinder, a damping valve provided in the piston, and in the vicinity of the stationary state of the ride In a hydraulic shock absorber provided with a bypass passage that lowers the damping force by communicating the upper oil chamber and the lower oil chamber while bypassing the damping valve during the expansion and contraction operation of the piston rod, the bypass passage is provided on the outer periphery of the cylinder. A recess formed along the direction, and a pair of upper and lower holes communicating with the upper oil chamber and the lower oil chamber, and a cylinder covering the recess is press-fitted into the outer periphery of the cylinder, and the recess hydraulic shock absorber with the engaging portion formed at a lower end to engage the stepped portion formed in the peripheral lower portion of the tubular body, characterized by comprising

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