JP3943270B2 - 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 hydraulic shock absorber having a vehicle height adjusting function.
[0002]
[Prior art]
A hydraulic shock absorber mounted on a vehicle basically functions to absorb road surface vibrations and improve the riding comfort of the vehicle. There are proposals to have an adjustment function, and various proposals have been made so far.
[0003]
Among them, there is a hydraulic shock absorber called a self-pumping type. In principle, this self-pumping type hydraulic shock absorber sucks oil from the reservoir into the cylinder when it expands and contracts due to road vibration. The cylinder pressure is increased by this, thereby increasing the vehicle height.
[0004]
Then, when the vehicle height reaches the set height, the self-pumping type hydraulic shock absorber causes the oil in the cylinder to flow out to the reservoir and increase the cylinder pressure further, that is, the vehicle height. The above-described increase is suppressed, and the vehicle height is maintained at a set height.
[0005]
On the other hand, in the hydraulic shock absorber disclosed in Japanese Patent Laid-Open No. 9-277814 previously proposed by the applicant of the present application, which is also a self-pumping type, the piston rod is inserted into the cylinder so as to be able to protrude and retract. A suspension spring that urges the shock absorber main body in the extending direction, that is, in a direction in which the piston rod protrudes from the cylinder, is interposed in the shock absorber main body under the support of the hydraulic cylinder mechanism.
[0006]
In the hydraulic shock absorber disclosed in this publication, the piston rod is raised and lowered by raising and lowering the lower end of the suspension spring by the expansion and contraction of the hydraulic cylinder mechanism by the pumping operation of the shock absorber body.
[0007]
Therefore, according to the hydraulic shock absorber disclosed in this publication, the same self-pumping type, but without causing an unnecessarily high pressure in the shock absorber body due to the pumping operation, as a result, the expansion and contraction of the shock absorber body. It will be possible to adjust the vehicle height.
[0008]
[Problems to be solved by the invention]
However, in the hydraulic shock absorber disclosed in this publication, there is a possibility that it is pointed out that there is the following inconvenience even though the predetermined self-pumping operation, that is, the vehicle height can be adjusted. .
[0009]
That is, in the hydraulic shock absorber described above, the shock absorber body is set to a double cylinder type having a reservoir on the outer peripheral side of the cylinder for compensating the oil temperature in the shock absorber body and the oil amount for pumping operation. In the shock absorber main body, the size in the radial direction is inevitably large, and it is assumed that a hydraulic cylinder mechanism for supporting a suspension spring is interposed on the outer periphery of the shock absorber main body. There is a concern that it is likely to be lowered.
[0010]
And, in the shock absorber main body, the increase in the radial dimension generally leads to an increase in weight, and from this point of view, the mountability to the vehicle is reduced and the parts are reduced. If the increase in the number of points overlaps, it will also hinder cost reduction.
[0011]
The present invention was created in view of the above-described circumstances, and the object of the present invention is to reduce the overall diameter and weight, thereby improving the mountability on a vehicle and reducing the cost. It is possible to provide a self-pumping type hydraulic shock absorber which can be optimized and expected to improve its versatility.
[0012]
[Means for Solving the Problems]
  In order to achieve the above-described object, the hydraulic shock absorber according to the present invention includes a hydraulic cylinder mechanism in which a suspension spring for urging a shock absorber main body formed by inserting a piston rod into and out of the cylinder in a retractable direction is provided. The hydraulic cylinder mechanism is expanded and contracted by the pumping operation of the shock absorber body so that the piston rod that locks one end of the suspension spring is projected and retracted with respect to the cylinder. In the hydraulic shock absorber set, a reservoir communicating with the oil chamber in the cylinder is provided inside the upper end side of the cylinder to form the shock absorber body in a single cylinder type, and the cylinder is coupled to the vehicle body side In addition, the piston rod is coupled to the axle side, and the cylinder mechanism is provided on the outer periphery of the upper end of the cylinder, and the inner periphery of the annular cylinder body, An annular piston body that is slidably disposed between the outer periphery of the cylinder and engages the other end of the suspension spring; a pressure chamber defined by the cylinder, the annular cylinder body, and the piston body; The cylinder is opened to communicate the pressure chamber with the reservoir andAnnular piston bodyThe pressure release port is opened and closed, and the pressure release port is opened to exert a relief function when the annular piston body is stroked until it is in an excessively extended state.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on the illustrated embodiment. However, even in the hydraulic shock absorber according to the embodiment of the present invention, in principle, the hydraulic shock absorber disclosed in the above-mentioned publication Similarly, the self-pumping type is set.
[0016]
That is, the hydraulic shock absorber according to the present invention, as shown in FIG. 1, is a suspension that urges a shock absorber body (not shown) formed by inserting a piston rod 2 into and out of the cylinder 1 in the extending direction. While the spring 3 is interposed in the shock absorber body under the presence of the hydraulic cylinder mechanism 4, the hydraulic cylinder mechanism 4 is expanded and contracted by a pumping operation in the shock absorber body to lock one end of the suspension spring 3. 2 is set to appear and disappear from the cylinder 1.
[0017]
  And in this hydraulic shock absorber,A reservoir R communicating with the rod-side oil chamber R1 and the piston-side oil chamber R2 in the cylinder 1 is provided inside the upper end side of the cylinder 1 to form the shock absorber body in a single cylinder type. In this case, in the embodiment of FIG. 3, the reservoir R also serves as the piston-side oil chamber.
Further, the cylinder 1 is coupled to the vehicle body side, and the piston rod 2 is coupled to the axle side, so that the hydraulic shock absorber main body is set upside down.
  The cylinder mechanism 4 is provided in an annular cylinder body 41 provided on the outer periphery of the upper end portion of the cylinder 1, and is slidably disposed between the inner periphery of the annular cylinder body 41 and the outer periphery of the cylinder 1. An annular piston body 42 that locks the other end of the spring 3, a pressure chamber R 3 that is separated by the cylinder 1, the annular cylinder body 41, and the piston body 42; R3 is constituted by a pressure release port 1b that communicates with the reservoir R and is opened and closed by the annular piston body 41. When the annular piston body 42 is stroked until it is in an excessively extended state, the pressure release port 1b is opened to discharge the oil in the pressure chamber R3 to the reservoir R so as to exert a relief function.
[0018]
To explain a little, first, the cylinder 1 constituting the shock absorber body is formed in a headed cylindrical shape having a so-called bottom end as an upper end, and an opening end as a lower end in the figure is closed by a bearing 11. Assuming that the shaft 11 of the bearing 11 has a seal 11a, the piston rod 2 is penetrated under the liquid-tight structure.
[0019]
In the illustrated embodiment, the cylinder 1 has a stepped portion 1a on the inner periphery near the upper end, and the base valve case 12 is locked to the stepped portion 1a from below.
[0020]
The upper end of the inner cylinder 13 accommodated in the cylinder 1 is locked to the lower end on the outer peripheral side of the base valve case 12, and the lower end of the inner cylinder 13 is placed on the bearing 11 described above with the stopper 14 disposed. It is supposed to abut.
[0021]
The stopper 14 closes the lower end of the inner cylinder 13 while penetrating the piston rod 2 through the shaft core portion, and functions as a regulator for the stroke amount of the piston rod 2.
[0022]
Therefore, it is needless to say that the stopper 14 may be omitted from the viewpoint of increasing the stroke amount of the piston rod 2.
[0023]
The base valve case 12 defines the above-described reservoir R on the inner circumference on the upper end side of the cylinder 1, while allowing a predetermined damping force while allowing communication with the inner circumference side reservoir R of the inner cylinder 13. And a pressure side check valve 12b that allows only communication of the reservoir R to the inner peripheral side of the inner cylinder 13 while being in parallel with the pressure side damping valve 12a.
[0024]
The inner cylinder 13 constitutes a cylinder in a substantial sense as the outer periphery of a piston 21 described later is slidably slidably contacted on the inner periphery thereof. Although it is disadvantageous in that the number is increased, it is advantageous in that the inner circumference of the cylinder 1 does not have to be processed for the cylinder.
[0025]
In the illustrated embodiment, an eye 15 is provided at the upper end of the cylinder 1 to enable connection to the vehicle body side of the vehicle.
[0026]
Next, the piston rod 2 constituting the shock absorber body has the above-described piston 21 at the upper end, which is the base end located in the cylinder 1, that is, in the inner cylinder 13, and the opening in the cylinder 1. A spring receiver 22 is provided at the lower end, which is the tip that projects outward from the end.
[0027]
The spring receiver 22 is provided with an eye 22a that allows the lower end of the piston rod 2 to be connected to the vehicle axle.
[0028]
As described above, the piston 21 is slidably accommodated in the inner cylinder 13, and at this time, the rod-side oil chamber R1 serving as the extension-side oil chamber in the inner cylinder 13; The piston side oil chamber R2, which is the pressure side oil chamber, is defined as being partitioned.
[0029]
The piston 21 includes an extension-side damping valve 21a that generates a predetermined damping force while allowing the rod-side oil chamber R1 to communicate with the piston-side oil chamber R2, and a piston in parallel with the extension-side damping valve 21a. An extension side check valve 21b that allows only the side oil chamber R2 to communicate with the rod side oil chamber R1.
[0030]
Incidentally, the extension side check valve 21b is set so as to have a so-called back pressure and functions as a pressure-side damping valve. Of course, as with the pressure side check valve 12b described above, a simple check valve that prevents so-called backflow may be set (see FIG. 2).
[0031]
Further, as described above, the suspension spring 3 has a lower end that is one end locked to a spring receiver 22 connected to the tip of the piston rod 2 and an upper end that is the other end locked to a hydraulic cylinder mechanism 4 described later. As a result, the piston rod 2 tends to protrude from the cylinder 1, that is, the shock absorber body is urged in the extending direction.
[0032]
Therefore, in the shock absorber body configured as described above, the extension side damping valve 21a and the compression side damping are used when the piston rod 2 is moved in and out of the cylinder 1 so that the suspension spring 3 is expanded and contracted. In the illustrated embodiment, further, in the illustrated embodiment, the extension side check valve 21b functioning as a compression side damping valve generates the respective damping forces on the extension side and the compression side, each having a predetermined magnitude.
[0033]
In this shock absorber body, the reservoir R is formed inside the cylinder 1 on the upper end side, and the reservoir is disposed in the cylinder as in the hydraulic shock absorber disclosed in the above-mentioned conventional publication. Since it is not set as the structure which has in an outer periphery, it becomes possible to restrain the dimension of the radial direction in this buffer body small.
[0034]
Therefore, in the hydraulic shock absorber according to the present invention, even if a hydraulic cylinder mechanism 4 described later is interposed on the outer periphery of the shock absorber body, the radial dimension of the hydraulic shock absorber should not be increased unnecessarily. Is possible.
[0035]
In the present invention, since the shock absorber body is set to a so-called inverted type, the hydraulic cylinder mechanism 4 is interposed in the vehicle body side member that is the cylinder 1. Therefore, the hydraulic cylinder mechanism 4 is connected to the piston rod 2. Compared with the case where the vehicle is mounted on the axle side member, the chance of being covered with mud is reduced in the on-vehicle state, which is advantageous in ensuring the operability and durability of the hydraulic cylinder mechanism 4.
[0036]
By the way, the hydraulic cylinder mechanism 4 embodies that the hydraulic shock absorber according to the present invention is set to a self-pumping type, and as described above, the hydraulic cylinder mechanism 4 expands and contracts by the pumping operation in the shock absorber body. Is set.
[0037]
That is, in the illustrated embodiment, the hydraulic cylinder mechanism 4 includes an annular cylinder body 41 whose base end is fixedly held on the outer periphery of the upper end of the cylinder 1 constituting the shock absorber body, An annular piston body 42 slidably accommodated in a gap (not shown) formed between the outer periphery of the cylinder 1 and the annular piston body 42 is accommodated in the gap. It is configured to expand and contract by supplying and discharging hydraulic pressure to and from the pressure chamber R3, which is an oil chamber formed by being mounted.
[0038]
The annular piston body 42 also serves as a spring receiver that locks the upper end of the suspension spring 3. Therefore, in the hydraulic cylinder mechanism 4, when no hydraulic pressure is applied to the pressure chamber R 3. The annular piston body 42 is pushed into the annular cylinder body 41 by the urging force of the suspension spring 3 to be in a contracted state.
[0039]
In the hydraulic cylinder mechanism 4, the annular piston body 42 protrudes from the annular cylinder body 41 against the urging force of the suspension spring 3 when a predetermined hydraulic pressure is supplied to the pressure chamber R 3. And become stretched.
[0040]
In the hydraulic cylinder mechanism 4, in the illustrated embodiment, when the annular piston body 42 protrudes from the annular cylinder body 41 with a large stroke and is in an over-extended state, the pressure chamber R3 is a cylinder. 1 is set so as to communicate with the reservoir R through the open pressure release port 1b, and is configured to exhibit a so-called relief function.
[0041]
In the case where the relief function is exhibited by providing the pressure release port 1b as described above, compared to the case where the relief function is exhibited by providing a so-called valve configuration in the hydraulic cylinder mechanism 4, This is advantageous in that the configuration is simple.
[0042]
On the other hand, as described above, the supply / discharge of the hydraulic pressure to / from the pressure chamber R3 in the hydraulic cylinder mechanism 4 is embodied by the pumping operation in the shock absorber body, but the configuration for realizing this pumping operation is as follows. It becomes as follows.
[0043]
That is, first, the shock absorber main body has a pump rod 31 suspended from the shaft core portion in the cylinder 1 and a pump housing (not shown) into which the lower end side of the pump rod 31 can be inserted and retracted. Thus, the pump chamber P defined by the lower end of the pump rod 31 is formed in the pump housing.
[0044]
At this time, the pump rod 31 is arranged so that the lower end is suspended downward, that is, the opening end side of the cylinder 1 with the upper end connected to the lower surface side of the upper end portion of the cylinder 1.
[0045]
The pump rod 31 has a through hole 31a in the shaft core portion, and the through hole 31a is opened at the upper end of the cylinder 1 to communicate with the pressure chamber R in the hydraulic cylinder mechanism 4 described above. It is supposed that it communicates with the passage 1c.
[0046]
On the other hand, the pump housing is assumed to be replaced by the piston rod 2 in the illustrated embodiment. The pump housing is opened at the shaft core portion on the upper end side of the piston rod 2 and is disposed on the lower end side of the pump rod 31 described above. It is assumed that the hole 2a that allows insertion is provided, and the pump chamber P is defined at the lower end of the pump rod 31 in the hole 2a.
[0047]
In the pump chamber P, the lower end of the through-hole 31a opened in the shaft core portion of the pump rod 31 is opened. Therefore, the oil from the pump chamber P is supplied to the pressure chamber in the hydraulic cylinder mechanism 4. It can flow into R3.
[0048]
A check valve 31b for preventing the oil from the pressure chamber R3 from flowing back to the pump chamber P is disposed in the through hole 31a.
[0049]
Next, a passage 32 that is opened in the piston rod 2 and allows the inflow of oil from the rod-side oil chamber R1 is communicated with the pump chamber P. The passage 32 is connected to the oil from the pump chamber P. Is provided with a check valve 32a for preventing the oil from flowing back to the rod side oil chamber R1.
[0050]
Therefore, according to the above configuration, when the piston rod 2 is retracted with respect to the cylinder 1, the supply of the hydraulic pressure to the pressure chamber R3 is realized as follows.
[0051]
That is, when the piston rod 2 is extended, the oil from the rod side oil chamber R1 flows into the pump chamber P that is expanded through the passage 32. From this state, when the piston rod 2 is reversed and operated on the pressure side. Then, the oil from the pump chamber P to be contracted flows into the pressure chamber R through the through hole 31a.
[0052]
As a result, in the hydraulic cylinder mechanism 4, the hydraulic pressure reaches the pressure chamber R3. Therefore, the annular piston body 42 tends to protrude from the annular cylinder body 41, and the hydraulic cylinder mechanism 4 is extended.
[0053]
When the hydraulic cylinder mechanism 4 is extended, the upper end of the suspension spring 3 is pushed down, so that the piston rod 2 tends to protrude from the cylinder 1, and at this time, the so-called rod reaction force in the shock absorber main body. Will rise.
[0054]
On the other hand, the extension of the hydraulic cylinder mechanism 4 that is extended as described above is stopped by the following configuration.
[0055]
That is, first, it is assumed that a communication hole 31c is opened on the lower end side of the pump rod 31 so as to be parallel to the through hole 31a. The communication hole 31c has a lower end that opens into the pump chamber P. On the other hand, the upper end is assumed to open to the piston-side oil chamber R2 at the shaft portion of the pump rod 31.
[0056]
And the upper end of this communicating hole 31c is opened and closed according to the immersion state in the above-mentioned hole part 2a formed in the pump housing of the lower end side of the pump rod 31, ie, the upper end side of the piston rod 2. It is set to be.
[0057]
That is, when the lower end side of the pump rod 31 is shallowly immersed in the hole 2a, the upper end of the communication hole 31c opens into the piston-side oil chamber R2, but when the lower end side of the pump rod 31 is deeply inserted into the hole 2a, the communication hole It is set so that the upper end of 31c is obstruct | occluded by the inner periphery of the hole 2a.
[0058]
Therefore, as described above, when the hydraulic cylinder mechanism 4 is extended, the shock absorber body is in an extended state, that is, when the piston rod 2 protrudes from the cylinder 1, the lower end side of the pump rod 31 is It will come out of the hole 2a.
[0059]
As a result, the upper end of the communication hole 31c opens to the piston-side oil chamber R2, and therefore, the oil from the pump chamber P is not discharged to the pressure chamber R3 in the hydraulic cylinder mechanism 4 and is thus moved to the piston-side oil chamber R2. Thus, the extension of the hydraulic cylinder mechanism 4 is stopped.
[0060]
At this time, since the check valve 31b for preventing the oil from flowing out from the pressure chamber R3 side is disposed in the through hole 31a, the extended state in the hydraulic cylinder mechanism 4 is maintained.
[0061]
By the way, the contraction in the hydraulic cylinder mechanism 4 in which the extension operation is stopped as described above is realized by the following configuration.
[0062]
That is, a branch passage 31d is connected in a so-called branched state to the through hole 31a opened in the pump rod 31, and this branch passage 31d opens to the piston-side oil chamber R2 at the shaft portion of the pump rod 31. .
[0063]
Incidentally, the branch passage 31d is connected to the through hole 31a on the upstream side of the check valve 31b, and opens to the piston side oil chamber R2 below the opening position of the communication hole 31c.
[0064]
Therefore, when the pump rod 31 protrudes from the hole 2a of the piston rod 2 more than the above, that is, when the extended state of the hydraulic cylinder mechanism 4 is maintained, the above-described branch passage 31d is connected to the piston side oil. Opening to the chamber R2 will cause the oil from the pressure chamber R3 to flow into the piston-side oil chamber R2, and the hydraulic cylinder mechanism 4 will contract.
[0065]
As a result, when the hydraulic cylinder mechanism 4 is in the extended state and the vehicle height is high, for example, when the vehicle height is further increased due to a load drop or a decrease in the number of passengers, the vehicle height is As a result, the lift of the load and the occupant's boarding can be facilitated.
[0066]
Therefore, in the hydraulic shock absorber according to the present invention configured as described above, for example, the shock absorber main body which is contracted by a load or a passenger's boarding to reduce the vehicle height is expanded and contracted by the traveling of the vehicle. Thus, while generating a predetermined damping force, the hydraulic cylinder mechanism 4 is extended by the pumping operation.
[0067]
As a result, the shock absorber main body extends so as to balance the urging force of the suspension spring 3, and at this time, the vehicle height is raised, and for example, so-called bottoming in the vehicle is avoided.
[0068]
When the extension of the shock absorber body is continued, the extension of the hydraulic cylinder mechanism 4 is continued and the vehicle height reaches a predetermined state, the extension of the hydraulic cylinder mechanism 4 is stopped and maintained in the predetermined extension state, Further extension will be stopped.
[0069]
In addition, when the vehicle height is further increased due to unloading or a decrease in the number of passengers from the state in which the hydraulic cylinder mechanism 4 is maintained in a predetermined extended state, the hydraulic cylinder mechanism 4 contracts and the vehicle height is set to a predetermined value. It will be lowered to the height of the car.
[0070]
Each of the hydraulic shock absorbers shown in FIGS. 2 and 3 is obtained by changing the configuration of the hydraulic shock absorber shown in FIG. 1 except for the portion where the damping force is generated. .
[0071]
Incidentally, in each of the following embodiments, where the configuration is the same as that of the embodiment shown in FIG. 1, the same reference numerals are given in the drawing, and detailed description thereof is omitted. The following description focuses on the features of each embodiment.
[0072]
First, the hydraulic shock absorber shown in FIG. 2 is omitted from the inner cylinder 13 in the embodiment shown in FIG. 1, and the cylinder 1 is composed of an upper headed cylinder 1d and a lower cylinder 1e. It is supposed to be composed of two parts.
[0073]
Therefore, in the case of this embodiment, as in the embodiment shown in FIG. 1, a cylinder body integrally having a so-called bottom end, that is, a so-called long headed cylindrical body is processed to produce the cylinder 1. As compared with the case of forming the cylinder, it is advantageous in that the cylinder 1 can be formed easily.
[0074]
Incidentally, in this embodiment, the extension side check valve 21b arranged in the piston 21 and in parallel with the extension side damping valve 21a is set as a simple check valve that prevents a so-called reverse flow without generating a compression side damping force. Has been.
[0075]
Next, the hydraulic shock absorber shown in FIG. 3 is set so as not to have the base valve case 12 in the cylinder 1 while being omitted from the inner cylinder 13 as in the embodiment shown in FIG. It is supposed to be done.
[0076]
Therefore, in the case of this embodiment, the cylinder 1 may be formed in a headed cylindrical shape having no stepped portion 1a on the inner periphery on the upper end side, and the number of processing steps is reduced. Since the case 12 is not provided, the weight can be reduced, and the number of valves can be reduced, which is advantageous in terms of cost.
[0077]
In this embodiment, the pressure-side damping force is generated by the pressure-side damping valve 21 c provided on the piston 21.
[0078]
Each of the hydraulic shock absorbers shown in FIGS. 4 and 5 is obtained by changing the configuration of the damping force generation portion with respect to each of the above-described hydraulic shock absorbers.
[0079]
Incidentally, in each of the following embodiments, where the configuration is the same as that of the embodiment shown in FIG. 1 described above, only the same reference numerals are given in the drawing, and detailed description thereof is omitted. In the following, the description will focus on the features that are characteristic of each embodiment.
[0080]
First, in the embodiment shown in FIG. 4, it is assumed that the damping force generated when the hydraulic shock absorber is extended is set to be stabilized.
[0081]
That is, in this embodiment, the other end, which is the upper end in the drawing of the passage 33 formed in the piston rod 2 and which opens at the lower end in the drawing to the pump chamber P, is the piston-side oil chamber R2. It is said to be open.
[0082]
That is, the embodiment shown in FIG. 1 is different from the embodiment in which the other end of the passage 32 having one end opened to the pump chamber P is opened to the rod side oil chamber R1.
[0083]
As in the case of the passage 32, the check valve 33a is disposed in the passage 33.
[0084]
Therefore, in this embodiment, the oil from the piston side oil chamber R2 flows into the pump P through the passage 33 and the check 33a during the expansion operation in which the pump P expands, and at this time, the rod side oil chamber The oil of R1 flows into the piston side oil chamber R2 through the extension side damping valve 21a disposed in the piston 21.
[0085]
As a result, in the embodiment shown in FIG. 1, when the upper end of the communication hole 31 c is closed, the oil in the rod-side oil chamber R <b> 1 passes through the extension-side damping valve 21 a disposed in the piston 21. It flows into the chamber R2 and generates a high damping force. However, when the upper end of the communication hole 31c is open, the oil in the rod side oil chamber R1 passes through the pump chamber P and the communication hole 31c, and the piston side oil. It will flow into chamber R2, and generation of a high damping force cannot be expected.
[0086]
On the other hand, according to this embodiment, the oil in the rod side oil chamber R1 passes through the expansion side damping valve 21a regardless of whether the upper end of the communication hole 31c is closed or opened. It will flow into chamber R2, and generation | occurrence | production of the stable expansion side damping force can be expected.
[0087]
Therefore, the embodiment shown in FIG. 1 is suitable for use when priority is given to the pumping operation by reducing the opportunity for the input of road surface vibration, whereas the pumping operation is necessary in this embodiment. Of course, it is suitable for use when there are many opportunities to input road surface vibration.
[0088]
Next, in the embodiment shown in FIG. 5, the damping force generated when the hydraulic shock absorber is extended and contracted is set so as to correspond to the use situation.
[0089]
That is, in this embodiment, when the communication hole 31c and the branch path 31d formed in the pump rod 31 are opened and closed with respect to the piston-side oil chamber R2, it is said that the sudden opening / closing state is prevented. Is set to
[0090]
That is, although not shown, when the hydraulic shock absorber is in a contracted state, the communication hole 31c and the branch path 31d are opposed to the inner periphery of the hole 2a that is opened in the shaft core portion of the piston 21 to form the pump chamber P. However, it is assumed that an annular gap 2b having a slightly enlarged diameter over an appropriate length is formed in the inner peripheral portion which is the upper end portion in the drawing of the hole portion 2a. When the communication hole 31c and the branch path 31d are opposed to the annular gap 2b, so-called slight oil flow is allowed under the state, and when the communication hole 31c and the branch path 31d open to the piston-side oil chamber R2. In other words, it is allowed to distribute oil entirely.
[0091]
Therefore, in the case of this embodiment, the pumping operation is continued when the communication hole 31c is in the closed state, and the contraction of the hydraulic cylinder mechanism 4 is prevented when the branch path 31d is in the closed state. As a matter of course, the pumping operation is stopped when the communication hole 31c opens into the piston-side oil chamber R2, and the contraction of the hydraulic cylinder mechanism 4 is allowed when the branch path 31d opens into the piston-side oil chamber R2. Even when both the communication hole 31c and the branch path 31d face the annular gap 2b, the same aspect as when both the communication hole 31c and the branch path 31d open to the piston-side oil chamber R2 is exhibited.
[0092]
However, when both the communication hole 31c and the branch path 31d are opposed to the annular gap 2b, the opening is not entirely open, so the pumping operation is performed when the piston 21 slides in the cylinder 1 at a high speed. In contrast, when the speed is low, the contraction of the hydraulic cylinder mechanism 4 is prioritized.
[0093]
That is, for example, when the vehicle travels off-road, priority is given to raising the vehicle height by pumping operation, and when the vehicle runs on-road, priority is given to lowering the vehicle height due to contraction of the hydraulic cylinder mechanism 4. Become.
[0094]
As a result, according to this embodiment, not only when an off-road vehicle travels off-road, but also a favorable traveling state can be obtained when on-road traveling at high speed.
[0095]
FIG. 6 shows an embodiment in which the connection between the communication hole 31c and the annular gap 2b is embodied as shown in FIG. 5 described above, but this will be described a little.
[0096]
First, as shown in FIG. 6A, in the pump rod 31, a shaft hole is formed with a through hole 31a, and a pump chamber (not shown) serving as a lower end portion of the through hole 31a in the figure. A check 31b is provided at the end of the opening.
[0097]
6B, the pump rod 31 has a shallow cutout surface 31e on the outer periphery of the portion closer to the upper end side in the drawing, and the outer periphery of the portion on the lower end side in the drawing. In addition, it has a notch surface 31f which is continuous with the shallow notch surface 31e but becomes deeper in comparison.
[0098]
At this time, the notch surface 31e corresponds to the annular gap 2b in the embodiment shown in FIG. 5, and the notch surface 31f similarly corresponds to the communication hole 31c.
[0099]
Therefore, according to this embodiment, when the hydraulic shock absorber expands and contracts and the pump rod 31 protrudes and retracts, for example, shallowly with respect to the hole 2a (see FIG. 5), the notch surface 31e becomes the piston side oil. The oil is exposed to the chamber R2 and is in a communication state, allowing a slight amount of oil to flow, and by being deeply intruded, the notch surface 31f is exposed to the piston-side oil chamber R2 and is in a communication state. Oil distribution will be allowed.
[0100]
In the embodiment shown in FIG. 6C, the configuration of the notch surface 31f is the same as that of the embodiment shown in FIG. 6A, but the upper side continuous with the notch surface 31f. In other words, the notch surface 31g is a tapered surface.
[0101]
Therefore, in the case of this embodiment, the amount of oil passing there is gradually increased according to the stroke as compared with the case of the embodiment shown in FIGS. 6 (a) and 6 (b). This is advantageous in that it can be increased or decreased.
[0102]
Although not shown, it is needless to say that the same configuration can be adopted for the branch path 31d in FIG.
[0103]
In the embodiments shown in FIGS. 4 and 5 described above, it is a matter of course that a predetermined pumping operation and a damping action are realized when the hydraulic shock absorber is expanded and contracted.
[0104]
【The invention's effect】
As described above, in the present invention, since the shock absorber body is set to be a single cylinder type having a reservoir in the cylinder, the reservoir is not configured to be provided on the outer periphery of the cylinder. Therefore, even if a hydraulic cylinder mechanism that raises and lowers one end of the suspension spring is interposed on the outer periphery of the shock absorber body, the radial size of the hydraulic shock absorber is not increased unnecessarily. It will be.
[0105]
Further, in the present invention, the shock absorber main body is set to a so-called inverted type, and the main operating portion in the hydraulic cylinder mechanism is interposed in the vehicle body side member that is a cylinder. Compared with the case where the vehicle is mounted on the axle side member, the chance of being covered with mud in the vehicle-mounted state is reduced, and the operability and durability of the main operating portion in the hydraulic cylinder mechanism can be ensured.
[0106]
And in this invention, when the cylinder is set in an upper and lower split mode, a cylinder body having a so-called bottom end integrally, that is, a headed cylindrical body is processed to form a cylinder This is advantageous in that the formation of the cylinder is facilitated.
[0107]
In the present invention, when the cylinder is not configured to have a base valve case, it may be formed into a headed cylindrical shape having no stepped portion on the inner periphery on the upper end side of the cylinder. Of course, it is advantageous in that the weight can be reduced because the base valve case is not provided, as well as the processing man-hours.
[0108]
Furthermore, in the present invention, by changing the oil supply route to the pump chamber, the hydraulic shock absorber prioritizing the pumping operation according to the vehicle type, and the pumping operation, of course, can effectively attenuate. A hydraulic shock absorber can be provided.
[0109]
In addition, a slight design change is made to the pump rod that constitutes the pump chamber, so that priority is given to raising the vehicle height when an off-road vehicle is traveling off-road, while the vehicle is traveling on-road at high speed. There is an advantage that priority can be given to lowering the height.
[0110]
As a result, according to the present invention, the overall diameter can be reduced and the weight can be reduced to improve the mounting property on the vehicle and the cost can be reduced. It will be optimal.
[Brief description of the drawings]
FIG. 1 is a front view of a hydraulic shock absorber according to an embodiment of the present invention, partly in cross section.
FIG. 2 is a view similar to FIG. 1 showing a hydraulic shock absorber according to another embodiment.
FIG. 3 is a view showing a hydraulic shock absorber according to another embodiment in the same manner as FIG.
4 is a view showing a hydraulic shock absorber according to another embodiment in the same manner as FIG.
FIG. 5 is a view showing a hydraulic shock absorber according to another embodiment in the same manner as FIG.
6 is a partial view showing a specific embodiment of the pump rod in FIG. 5,
(A) is a sectional view;
(B) is a front view showing from the YY line position in (a),
(C) is a figure which shows other embodiment similarly to (b).
[Explanation of symbols]
1 cylinder
1a Stepped part
1b Pressure release port
1c, 32 passages
1d Headed cylinder
1e cylinder
2 Piston rod
2a hole
2b Annular gap
3 Suspension spring
4 Hydraulic cylinder mechanism
11 Bearing
11a Seal
12 Base valve case
12a, 21c Pressure side damping valve
12b Pressure check valve
13 Inner cylinder
14 Stopper
15,22a Eye
21 piston
21b Extension check valve
22 Spring holder
31 Pump rod
31a Through hole
31b, 32a, 33a Check valve
31c communication hole
31d branch passage
31e, 31g Notch surface corresponding to annular gap
31f Notch surface corresponding to communication hole
32, 33 passage
41 Annular cylinder body
42 Annular piston body
R reservoir
R1 Rod side oil chamber
R2 Piston side oil chamber
R3 pressure chamber
P Pump room

Claims (1)

A suspension spring for energizing a shock absorber body extending in a retractable direction through which a piston rod can be inserted and retracted with respect to the cylinder is interposed in the shock absorber body under the hydraulic cylinder mechanism, while the hydraulic cylinder mechanism The hydraulic shock absorber is configured such that a piston rod that extends and contracts by a pumping operation in the shock absorber body and locks one end of the suspension spring is projected and retracted with respect to the cylinder. The shock absorber body is formed in a single cylinder type by providing a reservoir communicating with the oil chamber, and the cylinder is coupled to the vehicle body side, the piston rod is coupled to the axle side, and the cylinder mechanism is connected to the cylinder. An annular cylinder body provided on the outer periphery of the upper end portion, and the other end of the suspension spring are slidably disposed between the inner periphery of the annular cylinder body and the outer periphery of the cylinder. An annular piston body to stop, open and close the pressure chamber which is隔成between the cylinder and the annular cylinder body and the piston body, the pressure chamber being perforated in the said cylinder in the annular piston body while communicating with the reservoir A hydraulic shock absorber comprising: a pressure release port configured to open the pressure release port when a stroke is made until the annular piston body is in an excessively extended state.

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