JPH03140644A - Damping force generator - Google Patents

Abstract

PURPOSE:To prevent a valve plate from being yet more bent by supporting its radial intermediate part with the end of a stopper projection when the valve plate has received any load in the valve closing direction by differential pressure, in a damping force generator being built-in a hydraulic apparatus. CONSTITUTION:Each of valve plates 32, 33, 42 and 43 is opened or closed according to differential pressure lying between liquid chambers 5 and 6. When differential pressure in the direction of closing these valve plates 32, 33, 42 and 43 has worked, a radial intermediate part of the valve plate 32 is supported by an end face of a stopper projection 80, and since it seals a valve seat part 66 as opposing the differential pressure, such a possibility that the valve plate 32 might be unduly bent is checked in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a damping force generating device built into a fluid device such as a shock absorber or a pneumatic suspension.

[Prior Art] Shock absorbers and pneumatic suspensions used in vehicle suspension mechanisms have cylinders with internal fluid chambers,
The cylinder is configured to include a rod movably inserted in the axial direction of the cylinder, a damping force generating device provided in a liquid chamber inside the cylinder, and the like.

An example of a conventional damping force generating device is shown in FIG.

In this conventional device 100, a piston-shaped valve body 102 is provided inside a cylinder 101, and the inside of the cylinder 101 is partitioned into a first liquid chamber 103 and a second liquid chamber 104 by this valve body 102. ing. Valve body 102 is attached to the end of rod 105 by nut 115. Valve plates 10G and 107 each made of a disc spring are superimposed on the valve body 102. A plate mounting seat 110 is provided in the center of the valve body 102.
A valve seat portion 111 is provided near the outer peripheral portion of the valve seat 02. There is an annular groove 112 continuous in the circumferential direction between the plate mounting seat 11O and the valve seat portion Ill. Also,
Two straight orifice holes 113 and 114 are provided diagonally through the valve body 102 in the thickness direction.

In addition, in the above device 100, as illustrated in FIG. 9, the protruding height of the valve seat part it is made larger than the plate mounting seat 110 by h, and by tightening the nut 115, the valve plate I06°107 is initialized. A set load is applied by bending. The above height difference is about 0.1 +i+g.

In the device 100, when the rod 105 moves in the direction of withdrawal (extension side) with respect to the cylinder 101, the pressure in the first liquid chamber 103 increases, causing the liquid chamber 103.
When the differential pressure between
is bent in the valve opening direction, and a portion of the liquid in the first liquid chamber 103 flows into the second liquid chamber 104 through one orifice hole 114. Conversely, when the rod 105 moves in the direction in which it is pushed into the cylinder 101 (the contraction side), the pressure in the second liquid chamber 104 increases, causing the differential pressure between the liquid chambers 103 and 104 to rise to the level of the valve plate 106 on the upper side of the figure. When the set load due to the initial deflection is exceeded, this plate 106 is deflected in the valve opening direction, and a portion of the liquid in the second liquid chamber 104 flows into the first liquid chamber 103 through the other orifice hole 113.

In this specification, the valve plate (plate 10 in the example of FIG. 8) which bends in the valve opening direction when the rod moves to the extension side
7) is called the extension side valve plate, and the valve plate (plate 106 in the example of FIG. 8) that bends in the valve opening direction when the rod moves to the contraction side is called the contraction side valve plate. Also, the orifice hole through which the liquid flows when the rod moves toward the extension side (orifice hole 114 in the example in Figure 8) is called an expansion orifice, and the orifice hole through which the liquid flows when the rod moves toward the contraction side (the orifice hole in the example in Figure 8) is called an expansion orifice. In the example, orifice hole 1
13) is called the contraction orifice.

An example of damping force characteristics is shown in FIG. Inflection point al in the same figure
+a2, the valve plates 108, 107 begin to open. The bending point a1 of the damping force characteristic on the extension side depends on the extension side valve plate 107, and the bending point a2 of the damping force characteristic on the contraction side depends on the compression side valve plate 106.

[Problems to be Solved by the Invention] As described above, each valve plate 106, 107 is set with an initial deflection, and also functions as a check valve that opens and closes depending on the direction of the differential pressure. For this reason, when a large differential pressure in the direction of closing the valve plates 106 and 107 acts, the valve plate 106 not only bends greatly as shown by the two-dot chain line in FIG. In such a case, the valve plate 106 may be destroyed. In particular, for the contraction side valve plate 106, in order to lower the damping force on the contraction side than on the expansion side, the number of stacked plates toe may be reduced (or the plate thickness of the plate 106 may be made thinner). The pressure resistance when subjected to differential pressure in the valve closing direction becomes an issue.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a damping force generating device that can suppress generation of excessive stress on a valve plate due to differential pressure.

[Means for Solving the Problems] The present invention, which was developed to achieve the above object, is a damping force generating device comprising a disc-shaped valve body and a valve plate superimposed on the end face of the valve body. The valve body has a plate mounting seat provided on the end face, and a valve body that is provided continuously in the circumferential direction near the outer periphery of the end face and has a protruding height greater than the plate mounting seat, and has a plate mounting seat provided on the end face. A valve seat part that contacts the valve plate in a bent state, an annular groove that is continuous in the circumferential direction of the valve body between the plate mounting seat and the valve seat part, and a groove bottom of the annular groove in the circumferential direction of the valve body. a plurality of orifice holes that open at intervals, and a plurality of orifice holes that are arranged at the groove bottom of the annular groove independently from each other in the circumferential direction of the valve body and alternately with the openings of the orifice holes that define a radial intermediate portion of the valve plate. It is equipped with a plurality of supporting struts and buckwheat protrusions.

[When the valve plate receives a load in the valve closing direction due to the differential pressure, the radially intermediate portion of the valve plate is supported by the end surface of the stopper convex part, and the nocle plate is prevented from flexing any further.] Ru. Also, when the valve plate is bent in the valve opening direction due to a pressure difference in the opposite direction to the above, the liquid ejected from the orifice opening in the annular groove enters the annular groove, and the flow rate is moderated while the liquid flows around the circumference inside the annular groove. quickly spreads in the direction of
) Push the valve plate open.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 7.

Pneumatic hydraulic suspension 1 for a vehicle illustrated in FIG.
is equipped with a hollow cylinder 2. A damping force generating device 3 is provided inside the cylinder 2, and the damping force generating device 3 divides the inside of the cylinder 2 into a first liquid chamber 5 and a second liquid chamber 6. The liquid chambers 5 and 6 are filled with oil as a working fluid. A hollow rod 8 is inserted into the cylinder 2 so as to be movable in the axial direction. A liquid passage 9 is provided in the center of the rod 8 along the axial direction. The connecting part 10 attached to the lower part of the cylinder 2 is connected to a wheel side member (not shown). A connecting component 11 provided on the upper end side of the rod 8 is fixed to a member on the vehicle body side (not shown).

A subchamber 16 is attached to a bracket 15 provided on the top of the rod 8. The inside of the subchamber 16 is divided into an air chamber 1 by a partition member 17 using a metal bellows.
8 and a liquid chamber 19. A liquid chamber 19 filled with hydraulic fluid is connected to the intra-rod liquid path 9 via a communication hole 21 . The intra-rod liquid path 9 communicates with the second liquid chamber 6. The air chamber 18 contains an inert gas such as nitrogen gas, for example, 50 to 1
It is sealed at a pressure of around 0.00 kg f/cm2. The pressure of the gas acts in a direction to push the rod 8 out of the cylinder 2.

Next, the damping force generating device 3 will be explained.

As shown in an enlarged view in FIG. 6, a stud 26 having an axial communication hole 25 is fixed to the end of the rod 8.

A valve assembly 27 is assembled to this stud 26. The valve assembly 27 includes a piston-shaped first valve body 31 located on the lower side in the figure, and a plurality of valve plates 32.33 and spacer plates 34.3 superimposed on both end surfaces of the valve body 31, respectively.
5, a disk-shaped second valve body 41 housed in a sub-case 40, and a valve plate 42.43 and a spacer plate 44.45 superimposed on both end surfaces of this valve body 41. There is. These parts are tightened together in the thickness direction by a nut 51 via a washer 50.

The valve plates 32, 33, 42, 43 have an outer diameter dls, as shown in FIG. 3 as a representative of the first plate 32.
It has an annular shape with an inner diameter of d2, and a plate thickness of, for example, O, la.
It is a metal disc spring around +m.

An example of the first valve body 31 is shown in FIGS. 1 and 2. The stud 26 is located in the center of the valve body 31.
A through hole 55 is provided for the insertion of the. Further, a plurality of expansion orifice holes 56 and a plurality of contraction orifice holes 57 are provided that diagonally penetrate through the valve body 31 in the thickness direction. The valve body 31 has a pair of end faces 60°61. Annular plate mounting seats 62 and 63 are provided near the center of these end surfaces 60 and 61, that is, near the opening edge of the through hole 55. At this plate mounting seat 62.63, the valve plate 32.
33 is tightened by a nut 51 in the thickness direction. The valve plates 32, 33 therefore have a fixed end on their inner diameter side and a free end on their outer diameter side.

Circumferentially continuous annular valve seat portions 66 and 67 are provided near the outer periphery of the end surfaces 60 and 61. This valve seat portion 66°67 is concentric with the plate mounting seat 62,63.

The valve seat portions 66 and 67 are provided with a height difference H such that the protrusion height is greater than that of the plate mounting seats 62 and 63, as shown in FIG. 4 as a representative. The height difference H is, for example, 0. It is about la+a. By providing such a height difference H, a set load due to initial deflection is applied when the valve plates 32, 33 are tightened with the nuts 51.

Plate mounting seat 62.63 and valve seat part 66.67
An annular groove 70, 71 continuous in the circumferential direction of the valve body 31 is provided between the valve body 31 and the valve body 31.

One end side open portion 57a of the contraction orifice hole 57 is located in the groove bottom 72 of the annular groove 70 located on the upper side of the figure in the valve body 3.
Openings are made at equal intervals in the circumferential direction of 1.

The other end side openings 57b of the contraction orifice hole 57 are opened outside the valve seat portion 67 on the lower side in the figure at equal intervals in the circumferential direction. In the groove bottom 73 of the annular groove 71, one end opening portions 56b of the expansion orifice holes 56 are opened at equal intervals in the circumferential direction of the valve body 31, respectively. The openings 56a at the other end of the expansion orifice hole 56 are opened outside the valve seat portion 66 on the upper side in the figure at equal intervals in the circumferential direction.

A plurality of stopper protrusions 80.81 are provided on the groove bottoms 72.73 of the annular grooves 70.71, respectively.

These stopper projections 80.81 are arranged independently from each other and at equal intervals in the circumferential direction of the valve body 31.

The end faces of the stopper convex portions 80° and 81 are respectively opposed to the radially intermediate portions of the valve plates 32° and 33. The protruding height of these stopper projections 80.81 is equivalent to the height of the plate mounting seat 62.63. However, it may be slightly lower than the plate mounting seats 62, 63 as long as it is within the allowable range.

As shown in FIG. 1 as a representative of one end surface 60, in one annular groove 70, adjacent stopper convex portions 8
The orifice opening 57a is located between 0.80 and 0.80. In the other annular groove 71, an orifice opening 56a is arranged between adjacent stopper projections 81,81.

A circumferential groove 8 provided on the outer peripheral surface of the valve body 31
2 is fitted with a sliding bearing 83 (see FIG. 6).

The second valve body 41 housed in the subcase 40 is normally used in the damping force soft mode,
Since the problem of reverse warpage as in the case of the valve plates 32 and 33 described above does not occur much, the stopper convex portion is not necessary. However, when used in the medium damping force mode, a valve body having a structure substantially similar to that of the first valve body 31 described above is adopted. That is, plate mounting seats 85, 86 and valve seat portions 87° and 88 having the same gist as above,
An annular groove 89.90, a plurality of expansion orifice holes 91, a plurality of contraction orifice holes 92, and an annular groove 89.90.
It is configured to include a plurality of stopper convex portions 93 and 94 provided at the bottom of the groove.

The outer diameters of the spacer plates 34, 35, 44°45 are approximately the same as the outer diameters of the plate mounting seats 62, 63, 85°86. A bypass passage 96 (see FIG. 6) provided in the stud 26 communicates with the communication hole 25 via an orifice 97.

Next, the operation of the embodiment of the apparatus having the above configuration will be explained.

In FIG. 6, when the rod 8 moves relative to the direction in which it protrudes from the cylinder 2 (extension side), a part of the liquid in the first liquid chamber 5 is transferred to the elongation orifice hole 56 of the first valve body 31.
, and flows into the second liquid chamber 6 side while bending the valve plate 33 on the lower side in the figure in the valve opening direction. At the same time, a part of the liquid in the first liquid chamber 5 passes through the expansion orifice hole 91 of the second valve body 41 and flows into the bypass flow path 96 while bending the valve plate 42 on the upper side in the figure in the valve opening direction. enter,
It flows into the second liquid chamber 6 side through the orifice 97, the communication hole 25, etc. In this way, damping force on the extension side is obtained. Also,
When the rod 8 moves to the extension side, the amount of insertion of the rod 8 into the cylinder 2 decreases, so the subchamber 16
A part of the liquid inside flows into the cylinder 2, the air chamber 18 expands, and the repulsive force of the gas decreases.

Contrary to the above, when the rod 8 is relatively moved in the direction in which it is pushed into the cylinder 2 (the contraction side), a part of the liquid in the second liquid chamber 6 flows into the contraction orifice hole 57 of the first valve body 31. As shown, the liquid flows into the first liquid chamber 5 while bending the valve plate 32 on the upper side in the figure in the valve opening direction. At the same time, the second
A part of the liquid in the liquid chamber 6 passes through the flow hole 25, the orifice 97, and the bypass flow path 96, and then passes through the contraction orifice hole 92 of the second valve body 41, and moves toward the lower valve plate 43 in the valve opening direction. It flows into the first liquid chamber 5 side while being bent. In this way, damping force on the compression side is obtained. Moreover, when the rod 8 moves to the contraction side, a part of the liquid in the cylinder 2 flows into the liquid chamber 19 of the sub-chamber 16 as the amount of pushing of the rod 8 into the cylinder 2 increases, so that the air chamber 18 is further compressed, and the repulsive force of the gas increases. In addition, so that the damping force on the compression side is smaller than the damping force on the extension side,
The number of valve plates 32, 33, 42, 43, the cross-sectional area of the orifice holes 56, 57, 91, 92, etc. are set appropriately.

As mentioned above, each valve plate 32.33°42.
Reference numeral 43 opens and closes depending on the pressure difference between the liquid chambers 5 and 6. This valve plate 32, 33° 42, . When a differential pressure in the direction of closing the valve 43 acts, the radially intermediate portion of the valve plate 32 is supported by the end face of the stopper convex portion 80, as shown in FIG. Since the valve seat portion 66 is sealed against the differential pressure, excessive bending of the valve plate 32 is suppressed.

When a differential pressure in the direction of opening the valve plate 32 acts, the liquid ejected from the opening 57a of the orifice hole 57 enters the annular groove 70, goes around the stopper protrusion 80, and moves the annular groove 70 in the circumferential direction. uniformly and quickly, the valve plate 32 is pushed open to open the valve. Therefore, the flux directly hitting the valve plate 32 is relaxed,
The flow state of the liquid in the annular groove 70 becomes favorable. The pressure caused by the flux ejected from the opening 57a can be smoothly propagated to the entire pressure receiving surface of the valve plate 32, thereby lifting the valve plate 32.

FIG. 7 compares the stress generated when a differential pressure in the direction of closing the valve plate 32 acts in the device of this embodiment and the stress generation situation in the conventional device without the stopper convex portion 80. The thickness of the valve plate 32 is 0.
．． 152 am, outer diameter 2811% inner diameter 14 mm, fixed end presser diameter, that is, outer diameter of spacer plate 34 18 ams
Number of valve plates 32: 2, height difference H-0, 1a+
m, the load due to the differential pressure is 285 kg, the inner diameter of the cylinder 2 is 3511%, and the outer diameter of the rod 8 is 25 kg.

As shown in FIG. 7, in the case of the conventional device, the absolute value of the stress σ at the fixed end is extremely large, and moreover, a large stress occurs at the radially intermediate portion. The tensile strength of the material used for the valve plate 32 is approximately 1
Since the stress is about 70 to 200 kg f/am2, the stress in conventional equipment is at its peak value (approximately 190 kg f/am2).
v2), the valve plate may be damaged.

On the other hand, in the device of this embodiment, the absolute value of the maximum stress is 50
Since it is less than kgf/mta2, there is no possibility that the valve plate 32 will be damaged.

Although the above description has been made regarding one valve plate 32, the same can be said about the other valve plate 33, and the same applies to the valve plates 42, 431 provided in the second valve body 41. Furthermore, it goes without saying that the damping force generating device of the present invention can be similarly used for fluid devices other than suspensions having the above structure.

[Effects of the Invention] According to the present invention, excessive bending of the valve plate is suppressed, the generation of excessive stress is prevented, and the structural integrity of the valve plate is ensured.

[Brief explanation of the drawing]

1 to 6 show one embodiment of the present invention, FIG. 1 is a plan view of the valve body, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is a valve body. Top view of the plate, 4th
The figure is a cross-sectional view showing part of the valve body and valve plate when λ pressure is applied, Figure 5 is a vertical cross-sectional view of a gas-liquid formal suspension equipped with a damping force generator, and Figure 6 is the same as Figure 5. FIG. 7 is a cross-sectional view showing a part of the suspension shown, FIG. 7 is a view showing the state of stress generated in the valve plate, FIG. 8 is a cross-sectional view of a conventional damping force generator, and FIG. FIG. 10 is an enlarged view of a part of the conventional device shown in FIG. 10, and is a diagram showing an example of damping force characteristics. 1... pneumatic hydraulic suspension, 2... cylinder,
3... Damping force generator, 5, 6... Liquid chamber, 8...
Rod, 31... Valve body, 32.33... Valve plate, 41... Valve body, 42.43.
... Valve plate, 56.57... Orifice hole,
60°61... end face of valve body, 6.2.63.
...Plate mounting seat, 66.67...Valve seat part, 70°71...Annular groove, 72.73...Groove bottom, 8
0.81...Stopper convex part, 85.86...Plate mounting seat, 87.88...Valve seat part, 89.9
0...Annular groove, 93.94...Stopper convex portion.

Claims (1)

[Claims] A damping force generating device comprising: a disc-shaped valve body provided in a liquid chamber inside a cylinder; and a valve plate superimposed on an end face of the valve body, A plate mounting seat provided on the end face, and a plate mounting seat provided continuously in the circumferential direction near the outer periphery of the end face and having a larger protruding height than the plate mounting seat and attached to the valve plate when the valve plate is bent. a contacting valve seat portion, an annular groove that is continuous in the circumferential direction of the valve body between the plate mounting seat and the valve seat portion, and a plurality of openings at the groove bottom of the annular groove at intervals in the circumferential direction of the valve body. a plurality of stopper convex portions arranged at the groove bottom of the annular groove independently of each other in the circumferential direction of the valve body and alternately with the openings of the orifice hole and supporting a radially intermediate portion of the valve plate; A damping force generator characterized by comprising: