JP4844945B2 - Hydraulic damper - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic damper, and more particularly, to a hydraulic damper in which a damping force is variable according to a stroke amount of a piston rod.
[0002]
[Prior art]
As a damper whose damping force is variable according to the stroke amount of the piston rod, for example, a friction damper as shown in JP-A-5-248468 is known.
[0003]
In this conventional friction damper, a free piston provided slidably on a rod (piston rod) is fitted to a cylinder, and a friction material provided on the outer periphery of the free piston is brought into contact with the cylinder. A stopper with which the free piston abuts is provided.
[0004]
Thereby, when the rod makes a large stroke, the free piston is moved together with the rod by the stopper to generate a high damping force. In addition, when the rod makes a small stroke, the rod strokes with the free piston away from the stopper, so that a smooth stroke (low damping force) of the rod is guaranteed.
[0005]
Such a friction damper is used, for example, in a fully automatic washing machine, and a friction damper is provided between a frame that forms the outline of the washing machine and a drum that is rotatably disposed in the frame, and the drum is rotated when the drum rotates. The vibration in the machine is reduced to suppress the vibration and noise of the washing machine.
[0006]
In general, in a fully automatic washing machine, when washing and rinsing (low-speed rotation) are finished and shifting to dehydration (high-speed rotation), vibration (swing) at the time of drum activation is large (amplitude) due to uneven clothing in the drum. Large), when the rotational speed increases to some extent, the vibration decreases (small amplitude).
[0007]
Therefore, when the vibration at the time of starting the drum is large, that is, when the stroke of the rod is large, a high damping force is generated to quickly suppress the vibration of the drum, and the vibration becomes small, that is, the rod stroke is small. In some cases, a low damping force can be used to prevent the fine vibrations of the drum from being transmitted to the frame.
[0008]
[Problems to be solved by the invention]
However, in the conventional friction damper, when the stroke of the rod is large, the rod and the free piston come into contact with each other through the stopper. However, both the mass of the rod and the free piston are large, and the free piston is stationary. Since the friction is large, the impact at the time of contact is large, and vibration and noise generated by the damper itself due to this impact have been a problem.
[0009]
In order to suppress this impact, for example, it is conceivable to reduce the mass of the free piston or to reduce the static friction of the free piston. It becomes impossible to suppress quickly.
[0010]
The present invention has been made in view of the above-mentioned problems that the friction damper cannot avoid, and provides a novel hydraulic damper that has the same characteristics as the damping force characteristics of the friction damper described above by a hydraulic system. The purpose is to do.
[0011]
[Means for Solving the Problems]
  In order to achieve the above-mentioned object, the invention of claim 1 includes a cylinder in which oil is sealed, and a slidably provided in the cylinder.alwaysA piston defined in two chambers, a piston rod having one end connected to the piston and the other end extended out of the cylinder, and the fluid flow between the two chambers is controlled when the piston rod slides. In a hydraulic damper consisting of a damping force generation mechanism that generates damping force
The damping force generation mechanism includes an oil / liquid passage communicating between the two chambers provided in the piston, and the piston without being biased.Both inside and outsideFree movement in the axial directionNaThe disk valve is configured to restrict the flow of oil in the oil passage by contacting the piston during a large stroke of the piston rod, and is separated from the piston during a small stroke of the piston rod. Open the oil passageThe damping force at the time of large stroke is larger than that at the time of small stroke.It is characterized by doing.
[0012]
With this configuration, when the piston rod has a large stroke, the disc valve restricts the flow of the oil in the oil passage and generates a high damping force. When the stroke is small, the oil passage is opened and the piston rod is smooth. Stroke (low damping force).
[0013]
According to a second aspect of the present invention, in the first aspect of the invention, the communication between the two chambers is blocked when the oil passage is in communication with the first oil-liquid passage that communicates between the two chambers and the disc valve contacts the piston. And a second oil liquid passage.
[0014]
In this case, at the time of a large stroke of the piston rod, the disc valve contacts the piston and the second fluid passage is shut off, and the fluid flows only through the first fluid passage. As a result, the fluid flow is reduced. Generates a high damping force.
[0015]
The invention of claim 3 is characterized in that, in the invention of claim 1, an oil hole is provided in the disc valve, and when the disc valve contacts the piston, the flow of the oil liquid is restricted by the oil hole.
[0016]
In this case, at the time of a large stroke of the piston rod, the disc valve comes into contact with the piston and the oil liquid flows through the oil hole. As a result, the flow of the oil liquid is reduced and a high damping force is generated.
[0019]
  Claim4The invention of claim 1 to claim 13The invention is characterized in that a volume variable body in which gas is sealed and at least part of which is recessed according to an increase in pressure in the cylinder chamber is provided in at least one of the two chambers of the cylinder.
[0020]
  In this case, when the piston rod is large and rapidly strokes to generate a high damping force, the volume variable body absorbs a sudden increase in pressure in the cylinder chamber, so that the transition to the high damping force can be made smooth. it can.
  According to a fifth aspect of the present invention, there is provided a cylinder in which oil is sealed, a piston that is slidably provided in the cylinder and defines the inside of the cylinder in two chambers, one end connected to the piston, and the other end is the In the hydraulic damper comprising: a piston rod extending outside the cylinder; and a damping force generating mechanism that generates a damping force by controlling the flow of the oil between the two chambers when the piston rod slides, the damping force The generating mechanism is composed of an oil / liquid passage communicating between the two chambers provided in the piston, and a disk valve having a spring biased in the valve opening direction and movable in the axial direction. When the piston rod is in a large stroke, the fluid flow in the fluid passage is restricted by contacting the piston, and when the piston rod is in a small stroke, the fluid passage is opened away from the piston.The damping force at the time of large stroke is larger than that at the time of small stroke.It is characterized by doing.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
[0022]
As shown in FIG. 1, the hydraulic damper 1 according to the first embodiment of the present invention has a double cylinder structure in which a cylinder 3 is provided in an outer cylinder 2 that forms an outer shell. A reservoir chamber 4 in which oil and gas are enclosed is formed between the cylinder 3 and the outer cylinder 2.
[0023]
A piston 5 is slidably inserted into the cylinder 3, and the piston 5 defines the inside of the cylinder 3 in two upper and lower chambers 3a and 3b. One end (lower end) of the piston rod 6 is fixed to the piston 5 by a nut 7, and the other end (upper end) of the piston rod 6 is extended to the outside of the cylinder 3 through a rod guide 8 and an oil seal 9. Yes.
[0024]
A base valve 10 that connects the cylinder lower chamber 3b and the reservoir chamber 4 is provided at the lower end of the cylinder 3, and a predetermined damping force (low damping force) is generated in the base valve 10 when the piston rod 6 is contracted. And a check valve 10b that allows oil to flow from the reservoir chamber 4 to the cylinder lower chamber 3b during the extension stroke of the piston rod 6.
[0025]
At the upper end of the piston rod 6 and the lower end of the outer cylinder 2, there are provided mounting eyes 11a and 11b for mounting the hydraulic damper 1 to mounted members (not shown) such as a frame and a drum of the washing machine.
[0026]
The piston rod 6 is provided with a fitting portion 6a. The piston 5 is fitted into the fitting portion 6a, and retainers 12a and 12b and cylindrical spacers 13a and 13b are fitted on the upper and lower sides of the piston 5. It is fitted to the joint 6a.
[0027]
On the upper side of the spacer 13a, when the piston rod 6 moves downward with respect to the later-described extension side disk valve 16, the impact when the extension-side disk valve 16 abuts on a later-described regulating member 18a is mitigated, A flexible small-diameter retainer 14a and a large-diameter retainer 15a that prevent deformation and breakage of the extension-side disk valve 16 are provided.
[0028]
Below the spacer 13b, when the piston rod 6 moves upward with respect to a contraction-side disk valve 17 described later, the impact when the contraction-side disk valve 17 comes into contact with a regulating member 18b described later is reduced. A flexible small-diameter retainer 14b and a large-diameter retainer 15b that prevent deformation and breakage of the compression-side disk valve 17 are provided.
[0029]
The members shown in 18a and 18b are restricting members that restrict the deformation of the retainers 14 and 15 of the large diameter and the small diameter to the back side, and the restricting member 18a is a rod when the full stroke of the hydraulic damper 1 is extended. It functions as a rebound stopper that abuts against the guide 8 and absorbs impact.
[0030]
The piston 5 includes a plurality of communication passages 19 and 19 (second oil-liquid passage) communicating with the cylinder upper and lower chambers 3a and 3b, an extension-side communication passage 20a, and a contraction-side communication passage 20b (first oil-liquid passage). 5 are formed at predetermined intervals in the circumferential direction. These communication passages 19, 19, the expansion side communication passage 20 a and the contraction side communication passage 20 b constitute an oil-liquid passage in the present invention.
[0031]
The communication passages 19 and 19 are set to have a flow passage area that has a small resistance to the circulation of the oil liquid, while the expansion side communication passage 20a and the contraction side communication path 20b have a large resistance to the circulation of the oil liquid. It is set to the flow path area to give (to restrict).
[0032]
On both upper and lower end surfaces of the piston 5, annular valve seats 21a and 21b are formed on which the expansion side and contraction side disk valves 16 and 17 are seated (separated).
[0033]
The extension-side disk valve 16 has its inner periphery slidably guided by the spacer 13a, and is not urged by an urging member such as a spring in the vertical direction with respect to the valve seat 21a formed on the piston 5. It is a floating valve that can freely move in the axial direction. This extension side disk valve 16 is seated on the valve seat 21a when the piston 5 moves largely upward (elongation stroke, large stroke) with respect to the cylinder 3. The communication path 19 and the contraction side communication path 20b are closed (blocked).
[0034]
The contraction side disk valve 17 is guided by a spacer 13b so that the inner periphery thereof is slidable, and can be freely moved in the axial direction with respect to the valve seat 21b formed on the piston 5 similarly to the extension side disk valve 16. It has become. The contraction-side disc valve 17 is seated on the valve seat 21b when the piston 5 moves greatly downward (contraction stroke, large stroke) with respect to the cylinder 3, and closes the communication passage 19 and the extension-side communication passage 20a ( Block).
[0035]
Here, the expansion-side and contraction-side disk valves 16 and 17, the communication passages 19 and 19 and the extension-side and contraction-side communication passages 20a and 20b constitute a damping force generation mechanism in the present invention.
[0036]
Next, the operation of the first embodiment of the present invention configured as described above will be described below.
[0037]
When the expansion and contraction side disk valves 16 and 17 slide with respect to the spacers 13a and 13b by about the axial length of the spacers 13a and 13b, that is, when the piston rod 6 makes a large stroke. 2, the state shown in FIG. 2 (the state where the expansion-side and contraction-side disc valves 16, 17 are separated from the valve seats 21a, 21b) and the state shown in FIG. 3 and FIG. In the state of being seated on the seats 21a and 21b), the expansion side and contraction side disk valves 16 and 17 and the piston 5 are relatively moved.
[0038]
When the piston rod 6 makes a large stroke in the extension direction (in the direction of arrow A in FIG. 3), the communication passages 19 and 19, the extension side communication passage 20a, and the contraction side communication passage 20b are opened at the beginning of the stroke (total). The flow area S) and the oil in the oil chamber R1 move to the oil chamber R2 with a small resistance.
[0039]
On the other hand, an annular passage 16a (flow passage area S1) formed between the outer peripheral edge portion of the extension-side disc valve 16 and the cylinder 3 circulates to the oil liquid flowing between the cylinder upper chamber 3a and the oil chamber R1. A resistance (diaphragm) is applied, and the movement of the extension side disk valve 16 in the vertical direction with respect to the cylinder 3 is restricted by this flow resistance.
[0040]
That is, since the total flow path area S is set larger than the flow path area S1 (S> S1), the piston 5 moves and approaches the expansion-side disk valve 16, and as a result, the expansion The side disc valve 16 is seated on the valve seat 21a.
[0041]
When the expansion-side disc valve 16 is seated on the valve seat 21a, the communication passages 19 and 19 and the contraction-side communication passage 20b are closed, and the oil / liquid passage communicating with the cylinder upper and lower chambers 3a and 3b extends as shown by an arrow in FIG. Only the side communication passage 20a is provided, and as a result, the flow of the oil in the oil passage is restricted and a high damping force is generated.
[0042]
Here, the flow passage area S2 of the extension side communication passage 20a is set smaller than the flow passage area S1 of the annular passage 16a (S2 <S1), and when the extension side disc valve 16 is seated on the valve seat 21a. The large downward deformation in the figure is prevented.
[0043]
The contraction-side disk valve 17 is in contact with the small-diameter retainer 14b and the large-diameter retainer 15b in this order, so that the downward movement is restricted.
[0044]
Further, when the piston rod 6 makes a large stroke in the contraction direction (in the direction of arrow B in FIG. 4), the communication passages 19 and 19, the expansion side communication passage 20a, and the contraction side communication passage 20b are opened at the beginning of the stroke. (Total flow area S), the oil in the oil chamber R2 moves to the oil chamber R1 with a small resistance.
[0045]
On the other hand, an annular passage 17a (flow passage area S1) formed between the outer peripheral edge of the compression-side disk valve 17 and the cylinder 3 flows to the oil liquid flowing between the cylinder lower chamber 3b and the oil chamber R2. A resistance (throttle) is provided, and the movement of the contraction-side disk valve 17 in the vertical direction with respect to the cylinder 3 is restricted by this flow resistance.
[0046]
That is, since the total flow path area S is set to be larger than the flow path area S1 (S> S1), the contraction side disk valve 17 and the piston 5 approach each other due to relative movement, resulting in contraction. The side disc valve 17 is seated on the valve seat 21b.
[0047]
When the compression-side disc valve 17 is seated on the valve seat 21b, the communication passages 19 and 19 and the extension-side communication passage 20a are closed, and the oil / liquid passage communicating the cylinder upper and lower chambers 3a and 3b is contracted as indicated by an arrow in FIG. As a result, the flow of the oil in the oil passage is restricted and a high damping force is generated.
[0048]
Here, the flow passage area S2 of the contraction side communication passage 20b is set smaller than the flow passage area S1 of the annular passage 17a (S2 <S1), and the contraction side disc valve 17 is seated on the valve seat 21b. The upper deformation in the figure is prevented.
[0049]
The extension-side disc valve 16 is in contact with the small-diameter retainer 14a and the large-diameter retainer 15a in this order, so that a large upward movement is restricted.
[0050]
Thus, when the piston rod 6 makes a large stroke in each of the extending direction and the contracting direction, the extending side and the contracting side disk valves 16 and 17 and the piston 5 move relative to each other in the vertical direction, The contraction side disk valves 16 and 17 are seated on the valve seats 21a and 21b, respectively, so that the oil liquid flows only through the expansion side and the contraction side communication paths 20a and 20b. Is squeezed to generate a high damping force.
[0051]
At this time, even if the expansion and contraction side disk valves 16 and 17 collide with the valve seats 21a and 21b, the small diameter retainers 14a and 14b, and the large diameter retainers 15a and 15b, the mass of the disk valves 16 and 17 is small. Therefore, it is possible to suppress the generation of vibration and sound due to the collision.
[0052]
When the expansion and contraction side disk valves 16 and 17 slide with respect to the spacers 13a and 13b within the axial length of the spacers 13a and 13b, that is, when the piston rod 6 makes a small stroke. Since the annular passages 16a and 17a cause a flow resistance in the oil liquid flowing through the cylinder upper chamber 3a and the oil chamber R1, and the cylinder lower chamber 3b and the oil chamber R2, respectively, the flow resistance causes the expansion side and the contraction side disk valves. The movement of 16 and 17 in the vertical direction with respect to the cylinder 3 is restricted, and the state shown in FIG. 3 and FIG. 4 is gradually returned to the state shown in FIG. 2 by repeating small stroke vibration.
[0053]
Then, the piston rod 6 strokes within a range in which the expansion side and contraction side disk valves 16 and 17 are separated from the valve seats 21a and 21b.
[0054]
Therefore, when the piston 5 makes a small stroke in the extending and contracting directions, the oil liquid in the oil chambers R1 and R2 formed between the extending and contracting side disk valves 16 and 17 on the upper and lower end faces of the piston 5 is removed. Since the oil passages R1 and R2 are moved back and forth via the communication passages 19 and 19, the expansion side communication passage 20a and the contraction side communication passage 20b (the total volume of the oil chambers R1 and R2 is not increased or decreased), the oil liquid The passage has a small resistance (low damping force), and the piston rod 6 can move.
[0055]
According to the first embodiment configured as described above, at the time of a large stroke in which the piston rod 6 of the hydraulic damper 1 strokes beyond the axial length of the spacers 13a, 13b, the expansion side and the contraction side disk valves 16, 17 are oiled. A high damping force can be generated by restricting the flow of the oil in the liquid passage.
[0056]
Further, when the piston rod 6 is stroked within the range of the axial length of the spacers 13a and 13b, the expansion side and the contraction side disk valves 16 and 17 open the oil passage so that the piston rod 6 moves smoothly (low Damping force).
[0057]
Further, since the masses of the expansion side and contraction side disk valves 16 and 17 are significantly smaller than the free piston of the friction damper described in the prior art, the expansion side and contraction side disk valves 16 and 17 are connected to the piston 5. The impact at the time of contact is small, and vibration and noise generated by the hydraulic damper 1 itself can be reliably prevented.
[0058]
In the first embodiment, the extension side communication passage 20a and the contraction side communication passage 20b are provided as the first oil / liquid passages so as to communicate with the upper and lower sides of the piston 5. However, the present invention is not limited to this. The side valve seats 21a and 21b are each provided with a plurality of cutouts in the radial direction, and the cylinder upper and lower chambers 3a and 3b are connected to the communication passages 19 and 19 (second oil-liquid passage) through the cutouts (first oil-liquid passage). You may make it communicate with.
[0059]
Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, in contrast to the first embodiment, particularly when the piston rod 6 makes a large stroke toward the expansion side and the contraction side and the stroke speed is high, the damping force suddenly rises (in FIG. 9). (Dashed line). In addition, the same code | symbol is attached | subjected to the same part as 1st Embodiment, and only a different part is demonstrated.
[0060]
As shown in FIG. 5, the cylinder upper chamber 3a in the cylinder 3 of the hydraulic damper 1A is provided with an annular air bag 30a (volume variable body) in which air (gas) is hermetically sealed. The outer periphery is fitted into the cylinder 3 and is positioned below the rod guide 8.
[0061]
The air bag 30a is formed of a rubber flexible thin film and is recessed as the pressure in the cylinder upper chamber 3a increases.
[0062]
A receiving member 31 having a substantially U-shaped cross section is screwed to the piston rod 6 at a lower portion of the nut 7 screwed to the piston rod 6, and an air bag 30b is provided inside the receiving member 31. (Volume variable body) is provided.
[0063]
The receiving member 31 prevents the air bag 30b from moving to the piston 5 side in the cylinder lower chamber 3b and being damaged when the piston rod 6 is operated.
[0064]
The air bag 30b is also formed of a flexible thin film made of rubber, and is recessed as the pressure in the cylinder lower chamber 3b increases.
[0065]
Next, the operation of the second embodiment of the present invention configured as described above will be described below. The basic operation is the same as that of the first embodiment described above, and only different operations will be described.
[0066]
When the piston rod 6 makes a large stroke toward the extension side and the stroke speed is high, the piston 5 abuts against the extension side disk valve 16 vigorously. In this case, the oil liquid on the upper side of the extension side disk valve 16 is compressed by the throttle action of the annular passage 16a, and the pressure in the cylinder upper chamber 3a suddenly increases. At this time, the air bag 30a in the cylinder upper chamber 3a. Is recessed, and an increase in pressure in the cylinder upper chamber 3a can be suppressed.
[0067]
As a result, as shown by the solid line in FIG. 9, the expansion-side damping force smoothly shifts to a high damping force, and the damping force rises rapidly as in the first embodiment (broken line in FIG. 9). Impact can be suppressed.
[0068]
Further, even when the piston rod 6 makes a large stroke toward the contraction side and the stroke speed is high, the air bag 30b provided in the cylinder lower chamber 3b is recessed to suppress an increase in pressure in the cylinder lower chamber 3b. As indicated by the solid line, the damping force on the contraction side smoothly shifts to a high damping force, and the impact can be suppressed.
[0069]
As described above, according to the second embodiment, the transition to the high damping force can be made smooth particularly when the piston rod 6 makes a large stroke toward the expansion side and the contraction side and the stroke speed is high. The impact generated by the damper can be reliably suppressed.
[0070]
Next, a modification of the second embodiment of the present invention will be described below.
[0071]
The embodiment shown in FIG. 5 described above is a so-called upright hydraulic damper that uses the piston rod 6 with the piston rod 6 facing upward, but may be used as an inverted type as shown in the modification of FIG. it can.
[0072]
That is, in FIG. 6, the damping valve 10 a and the check valve 10 b are fixed to the base valve 10 of the hydraulic damper 1 </ b> B by the fixing pin 40. The member 41 is integrally formed, and an air bag 40b (volume variable body) is provided inside the receiving member 41. The receiving member 41 prevents the air bag 40b from coming into contact with the bottom valve 10 or the like and being damaged when the hydraulic damper 1 is operated.
[0073]
Since the hydraulic damper 1B is used upside down, the reservoir chamber 4 is provided with a reservoir bag 4a in which gas for defining oil and gas is enclosed.
[0074]
Further, in another modification shown in FIG. 7, the receiving member 51 screwed to the lower end side of the fitting portion 6a of the piston rod 6 of the hydraulic damper 1C is formed in a box shape, and has an air bag 50b (volume) inside. (Variable body) is accommodated. The receiving member 51 is provided with a plurality of oil liquid passages 51a and 51a, and the oil liquid flows into the receiving member 51 without resistance through the oil liquid passages 51a and 51a. Accordingly, the hydraulic damper 1C of FIG. 7 can cope with both upright and inverted use conditions.
[0075]
Also in the hydraulic damper 1 </ b> C, a reservoir bag 4 a in which a gas for defining an oil liquid and a gas is enclosed is provided in the reservoir chamber 4.
[0076]
Further, in another modification shown in FIG. 8, the nut for fixing the piston 5 of the hydraulic damper 1D to the piston rod 6 and the variable volume body of the present invention are integrated. That is, the upper side of the substantially cylindrical cylindrical member 60 is a nut 60a, and the lower side of the cylindrical member 60 is a cylindrical part 60b that forms an air (gas) chamber 62, and further surrounds the cylindrical part 60b. A flexible thin film 61 made of rubber is provided, and the flexible thin film 61 and the cylindrical portion 60b constitute a variable volume body.
[0077]
Even in the hydraulic damper 1D configured as described above, when the pressure in the cylinder lower chamber 3b suddenly increases, a part of the variable volume body, that is, the flexible thin film 61 is recessed upward, and the cylinder lower chamber 3b It is possible to smooth the transition to a high damping force by suppressing an increase in pressure.
[0078]
Next, a third embodiment of the present invention will be described with reference to FIGS.
[0079]
The third embodiment differs from the first embodiment described above in that the shape of the piston and the disk valve, and a coil spring is provided between the upper end of the cylinder and the upper end of the piston rod. The same reference numerals are given to the same parts as the form, and only different parts will be described.
[0080]
Only a plurality of communication passages 19a and 19a (oil-liquid passages) communicating with the cylinder upper and lower chambers 3a and 3b are provided at a predetermined interval in the circumferential direction of the piston 5a to the piston 5a sliding in the cylinder 3 of the hydraulic damper 1E. The expansion side communication passage 20a and the contraction side communication passage 20b formed in the piston 5 of each embodiment described above are omitted.
[0081]
The flow passage areas of the communication passages 19a and 19a are set to be substantially the same flow passage area as the communication passages 19 and 19 of the above-described embodiments, and a small resistance is given to the circulation of the oil liquid.
[0082]
The upper and lower end surfaces of the piston 5a are formed with annular valve seats 210a and 210b on which the expansion and contraction side disk valves 160 and 170 are seated (separated), and the disk valves 160 and 170 are respectively connected to the valve seat 210a, 210b can be freely moved (floating) in the axial direction.
[0083]
Each disk valve 160, 170 is provided with a fixed orifice 160a, 170a (oil hole), and this fixed orifice 160a, 170a is provided on the inner diameter side (near the radial piston rod 6) of each valve seat 210a, 210b. Four locations are provided in the circumferential direction at positions substantially opposite to the communication passages 19a, 19a. The number of fixed orifices is not limited to four, and the diameter and number of fixed orifices may be set as appropriate in order to obtain a desired damping force.
[0084]
The flow areas of the fixed orifices 160a and 170a are set to be substantially the same as the flow area of the expansion side communication path 20a and the contraction side communication path 20b (S2) formed in the piston 5 of each embodiment described above.
[0085]
The flow passage areas (S3) of the annular passages 160b and 170b formed between the outer peripheral edge portions of the disc valves 160 and 170 and the cylinder 3 are the expansion side and contraction side disc valves 16 of the above-described embodiments. , 17 and the flow passage area (S1) of the annular passages 16a, 17a formed between the outer peripheral edge portion of the cylinder 3 and the cylinder 3, it is set so as to have a relationship of approximately S3 = S1-S2. Thereby, the vertical movement of the disc valves 160 and 170 with respect to the cylinder 3 is restricted.
[0086]
Here, the expansion and contraction side disk valves 160 and 170, the communication passages 19a and 19a, and the fixed orifices 160a and 170a constitute a damping force generation mechanism in the present invention.
[0087]
A spring seat 6 a that supports the upper end of the spring 200 is fixed to the upper end side of the piston rod 6 by welding, and the lower end of the spring 200 is supported by a cap 2 a that closes the upper end of the outer cylinder 2. A predetermined initial load is set on the spring 200 so that, for example, a rotary drum (vibrating member) such as a dryer can be supported in the axial direction at an intermediate extension position of the piston rod 6. Regardless of the present embodiment, the spring 200 can be used in the first and second embodiments described above according to the mounting structure to the vibration device.
[0088]
Also in the third embodiment configured as described above, at the time of a large stroke, the expansion side and the contraction side disk valves 160 and 170 are seated on the valve seats 210a and 210b, respectively, and the oil flows only through the fixed orifices 160a and 170a. As a result, the flow of the oil liquid in the oil liquid passage is restricted and a high damping force is generated. Moreover, the same effect as the first embodiment described above can be obtained.
[0089]
Furthermore, according to the third embodiment, fixed orifices 160a, 170a formed in the expansion side and contraction side disk valves 160, 170 in the same way as the expansion side and contraction side communication passages 20a, 20b of the above-described embodiments. Therefore, only the relatively thick communication passages 19a and 19a are formed in the piston 5a, and it is not necessary to provide the inclined thin extension side and contraction side communication passages 20a and 20b, thereby simplifying the manufacturing process. Cost can be reduced.
[0090]
Moreover, in each embodiment mentioned above, as shown in FIG.3 and FIG.4, since an oil liquid is return | folded via the annular channel | paths 16a and 17a, and flows through the expansion | extension side and shrinkage | contraction side communication paths 20a and 20b, At this time, it is conceivable that a vortex is generated on the downstream side of the outer peripheral edge portion of the expansion side and contraction side disk valves 16 and 17, thereby generating an operating sound.
[0091]
In the third embodiment, when the disc valves 160 and 170 are seated on the valve seats 210a and 210b, as shown by the arrows in FIG. The oil liquid does not flow in the peripheral portion, and the oil liquid flows linearly into the communication path 19a via the fixed orifices 160a and 170a, so that the generation of operation noise can be suppressed more reliably.
[0092]
As a modification of the third embodiment, in place of the disk valves 160 and 170 shown in FIG. 12, notched disk valves 161 and 171 provided with a plurality of notches 161a and 171a shown in FIG. 13 can be used. .
[0093]
In this case, the notches 161a and 171a are formed to extend so as to communicate with the communication passages 19a and 19a provided on the inner diameter side (near the radial piston rod 6) of the valve seats 210a and 210b of the piston 5a, and the notches 161a and 171a. The total flow path area of the annular passage (not shown) between the outer peripheral edge of the notch disk valves 161 and 171 and the cylinder 3 is the extension side and contraction side disk of each embodiment described above. The flow passage area (S1) of the annular passages 16a and 17a formed between the outer peripheral edge portions of the valves 16 and 17 and the cylinder 3 is set to be substantially the same.
[0094]
However, regarding the setting of the flow passage areas of the notches 161a and 171a, when the notch disk valves 161 and 171 are seated on the valve seats 210a and 210b, the front end side of the notches 161a and 171a on the piston rod 6 side and the valve seats. The fixed orifices 161b and 171b (oil holes) formed by being surrounded by the inner diameter side ridges of 210a and 210b are formed in the extension side communication path 20a and the contraction side communication path 20b (S2) formed in the piston 5 of the above-described embodiments. ) To be set to approximately the same flow path area as in (1).
[0095]
In each of the above-described embodiments, flow resistance is generated in the oil liquid flowing through the cylinder upper chamber 3a and the oil chamber R1, and the cylinder lower chamber 3b and the oil chamber R2, and the piston 5 (5a) is expanded and contracted. The side disk valves 16 (160, 161) and 17 (170, 171) are approached, but the present invention is not limited to this.
[0096]
That is, for example, when the hydraulic damper according to the present invention is used in a device having a high stroke speed at the time of a large stroke, even if the annular passage is enlarged (not squeezed), the expansion side and contraction side disks A pressure difference is generated between the front side and the back side of the valve, and the expansion side and the contraction side disk valve can approach the piston by this pressure difference. In this case, since the annular passage can be prevented from being throttled, a disk valve of a hydraulic shock absorber mounted on a normal vehicle or the like can be used widely.
[0097]
In the first and second embodiments described above, the expansion side and contraction side disk valves 16 and 17 are slidably fitted to the spacers 13 a and 13 b, and an annular shape is formed between the outer peripheral edge portion and the cylinder 3. Although the passages 16a and 17a are provided, the present invention is not limited to this. The communication passages 19 and 19, the expansion side and the contraction side communication passages 20a and 20b are appropriately disposed in the piston 5, and the expansion side and the contraction side disk valves are provided. A disc valve is slidably fitted into the cylinder, an annular passage is provided between the inner peripheral edge of the cylinder and the spacer, or a disk valve is slidably fitted to both the spacer and the cylinder. A communication passage may be provided in the radially intermediate portion of the first and second communication passages 19 and the expansion side communication passage 20a (or the contraction side communication passage 20b). In the third embodiment described above, the sliding portion of the disc valve can be easily set as described above without changing the positions of the communication passages 19a, 19a and the fixed orifices 160a, 170a.
[0098]
Further, in each of the above-described embodiments, the expansion side and contraction side disk valves 16 (160, 161), 17 (170, 171) are moved upward and downward with respect to the piston without being urged by a biasing member such as a spring. The floating valve can be moved freely in the axial direction, but this is not limited to this, and only when the floating valve is located near the valve closing, a weak spring that biases the floating valve in the valve opening direction with a weak force, You may arrange | position between the expansion side and contraction side disk valves and pistons.
[0099]
In this case, when the hydraulic damper is switched from the large stroke to the small stroke, the expansion side and the contraction side disk valve can be quickly separated from the piston, so that the generation of the high damping force to the smooth stroke (low damping force). You can switch quickly.
[0100]
The floating valve here is not only a valve that can move freely in the axial direction with respect to the piston without using a spring or the like, but the flow resistance of oil and the front and back sides of the valve. This includes a valve that can move in the axial direction with respect to the piston and be closed without being affected by the biasing force of the weak spring level.
[0101]
In addition, by appropriately changing the axial length of the spacers 13a and 13b, the generation timing of the high damping force can be easily changed, and it can be used for all purposes.
[0102]
Further, in each of the above-described embodiments, the present invention has been applied to a double cylinder structure hydraulic damper. However, the present invention is not limited to this, and may be applied to a single cylinder hydraulic damper having a free piston. it can.
[0103]
Furthermore, in the above-described second embodiment, the annular air bag 30a (not shown in FIGS. 6 to 8) provided in the cylinder upper chamber 3a is not fitted into the cylinder 3 and is not inserted into the cylinder 3 without the restriction member 18a. The upper part may be fitted to the piston rod 6, or the air bags 30b and 40b in FIGS. 5 and 6 may be fitted to the receiving members 31 and 41, respectively.
[0104]
In the second embodiment, the air bag (volume variable body) is provided in each of the cylinder upper and lower chambers. However, the initial operation direction of the hydraulic damper (from the state in which the hydraulic damper is not operated first) For example, when the initial operation direction is the expansion side, the air bag (volume variable body) on the cylinder lower chamber 3b side is omitted, and the initial operation direction is applied. When is on the contraction side, the air bag (volume variable body) on the cylinder upper chamber 3a side may be omitted.
[0105]
In the second embodiment described above, each air bag provided in the cylinder upper and lower chambers may be filled with a gas having a predetermined pressure. In this case, the air bag is appropriately attenuated by using an air bag whose gas pressure is adjusted appropriately. Power rise adjustment (tuning) becomes easy.
[0106]
Furthermore, in the above-described second embodiment, the one using a rubber flexible thin film as the volume variable body has been shown. However, the present invention is not limited to this, and a resin or metal bellows may be used.
[0107]
Moreover, you may use the volume variable body used in the above-mentioned 2nd Embodiment for the above-mentioned 3rd Embodiment.
[0108]
Furthermore, the hydraulic damper of the present invention is not limited to being applied to a washing machine, and vibrates greatly when the motor is started or when the rotational speed is switched, such as an air compressor. It can also be used for devices where vibration is small at times.
[0109]
【The invention's effect】
As described in detail above, according to the hydraulic damper of the first aspect, when the piston rod has a large stroke, the flow of the oil in the oil passage is restricted by the disc valve, and a high damping force is generated. Since the passage is opened and the piston rod can smoothly stroke (low damping force), the damping force does not become too high during a small stroke, and vibration during a large stroke can be suppressed quickly.
[0110]
According to the hydraulic damper of claim 2, in claim 1, the oil passage is composed of a first oil passage and a second oil passage that is disconnected when the disc valve contacts the piston. Therefore, it is possible to achieve a hydraulic damper with a simple structure that does not have excessively high damping force during a small stroke and can quickly suppress vibration during a large stroke.
[0111]
According to the hydraulic damper of claim 3, in claim 1, the oil hole is provided in the disc valve, and when the disc valve comes into contact with the piston, the flow of the oil liquid is restricted by the oil hole. Can be easily provided with a throttle passage, for example, by press working or the like, simplifying the manufacturing process and reducing costs.
[0113]
  Claim4According to the hydraulic damper of claim 1,3In the above, a variable volume body in which gas is sealed and at least part of which is recessed according to an increase in pressure in the cylinder chamber is provided in at least one of the two chambers of the cylinder, so that the piston rod is large and strokes quickly. When a high damping force is generated, the volume variable body absorbs a sudden increase in pressure in the cylinder chamber, so the transition to the high damping force can be smoothed, and the impact caused by the sudden rise of the damping force Can be reliably suppressed.
According to the hydraulic damper of the fifth aspect, when the piston rod has a large stroke, the flow of the oil in the oil passage is restricted by the disc valve to generate a high damping force, and when the piston rod has a small stroke, the oil passage is opened and the piston rod is opened. Can smoothly stroke (low damping force), so that the damping force does not become too high during a small stroke, and vibration during a large stroke can be suppressed quickly.
[0114]
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an entire hydraulic damper according to a first embodiment of the present invention.
FIG. 2 is an enlarged longitudinal sectional view of a piston portion (a damping force generation mechanism portion) of FIG.
FIG. 3 is an enlarged longitudinal sectional view of a piston portion when the hydraulic damper of FIG. 1 has a large stroke in the extending direction.
4 is an enlarged vertical cross-sectional view of a piston portion when the hydraulic damper of FIG. 1 has a large stroke in the contraction direction.
FIG. 5 is a longitudinal sectional view showing an entire hydraulic damper according to a second embodiment of the present invention.
FIG. 6 is a partially enlarged longitudinal sectional view showing a modification of the second embodiment.
FIG. 7 is a partially enlarged longitudinal sectional view showing another modification of the second embodiment.
FIG. 8 is a partially enlarged longitudinal sectional view showing still another modification of the second embodiment.
FIG. 9 is a diagram showing damping force characteristics of the second embodiment.
FIG. 10 is a longitudinal sectional view showing an entire hydraulic damper according to a third embodiment of the present invention.
11 is an enlarged longitudinal sectional view of the piston portion (damping force generating mechanism portion) of FIG.
12 is a plan view showing the disk valve of FIG. 10. FIG.
FIG. 13 is a partially enlarged longitudinal sectional view showing a modification of the disc valve of the third embodiment.
[Explanation of symbols]
1 Hydraulic damper
3 cylinders
5 piston
6 Piston rod
16, 160, 161 Extension side disk valve (damping force generation mechanism, floating valve)
17, 170, 171 Compression side disk valve (damping force generation mechanism, floating valve)
19, 19a Communication passage (oil-liquid passage, damping force generation mechanism, second oil-liquid passage)
20a Elongation side communication path (oil liquid path, damping force generation mechanism, first oil liquid path)
20b Shrinkage side communication path (oil liquid path, damping force generation mechanism, first oil liquid path)
30a, 30b Air bag (variable volume)
40b Air bag (variable volume)
50b Air bag (variable volume)
60b Tube part (variable volume)
61 Flexible thin film (variable volume)
160a, 161a Fixed orifice (damping force generation mechanism, oil hole)
170a, 171a Fixed orifice (damping force generation mechanism, oil hole)

Claims (5)

A cylinder filled with oil, a piston slidably provided in the cylinder and always defining two chambers in the cylinder, and one end connected to the piston and the other end extended outside the cylinder. A hydraulic damper including a piston rod and a damping force generation mechanism that generates a damping force by controlling the flow of the oil liquid between the two chambers when the piston rod slides,
The damping force generating mechanism includes an oil / liquid passage that communicates between the two chambers provided in the piston, and a disk valve that can freely move in the axial direction on both the inner and outer circumferences without being biased. The disk valve is configured to restrict the flow of oil in the oil passage by contacting the piston during a large stroke of the piston rod, and is separated from the piston during a small stroke of the piston rod. The hydraulic damper is characterized in that the damping force at the time of a large stroke is greater than that at the time of a small stroke . The fluid passage includes a first fluid passage that communicates between the two chambers, and a second fluid fluid passage that blocks communication between the two chambers when the disc valve contacts the piston. The hydraulic damper according to claim 1, wherein the hydraulic damper is configured. The disk valve is provided with an oil hole having a total area smaller than the total area of the oil liquid passage, and when the disk valve contacts the piston, the oil hole causes the oil liquid to flow through the oil hole. The hydraulic damper according to claim 1, wherein the hydraulic damper is narrowed down.   2. A variable volume body in which gas is sealed inside the cylinder and at least part of which is recessed according to an increase in pressure in the cylinder chamber is provided in at least one of the two chambers of the cylinder. The hydraulic damper as described in thru | or 3. A cylinder filled with oil, a piston slidably provided in the cylinder and defining the inside of the cylinder in two chambers, one end connected to the piston, and the other end extended out of the cylinder In a hydraulic damper comprising a piston rod and a damping force generation mechanism that generates a damping force by controlling the flow of oil between the two chambers when the piston rod slides,
The damping force generating mechanism includes an oil / liquid passage communicating between the two chambers provided in the piston, and a disk valve having a spring biased in the valve opening direction and movable in the axial direction. valve, the flow of hydraulic fluid in the hydraulic fluid passage aperture, spaced from the piston to open the hydraulic fluid passage when the small stroke of the piston rod by contacting the piston when a large stroke of the piston rod, the small A hydraulic damper characterized in that the damping force during a large stroke is greater than that during a stroke .

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