Damper, method for improving damper, and automobile

Abstract

To provide a damper after improvement having damping performance desired by a user and returned to an original position of a suspension so as not to erroneously operate a driving support mechanism by using the damper.SOLUTION: An end part of an outer tube 10 of the damper is cut, the end part is formed as an open end part closable by a cylindrical body 212 and a cap 214, and the periphery of the cylindrical body 212 is welded to the open end part. In the damper, the damper improvement method, and the automobile, the second spiral groove provided on the outer peripheral surface of the cap 214 can be screwed to the first spiral groove provided on the inner peripheral surface of the cylindrical body 212, the damping mechanism in which the flow rate adjusting valve covering the oil outflow hole connecting the two oil chambers of the damping mechanism pulled out from the open end portion is replaced is inserted into and stored in the outer tube 10, the second spiral groove is screwed to the first spiral groove to close the open end portion, and then the damper is returned to the original position where the damper is mounted.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to an improved damper and a vehicle in which a damper constituting an automobile suspension is improved to have the damping performance desired by the user and then returned to its original position on the suspension. Specifically, the present invention relates to an improved damper in which the piston, piston rod (hereinafter also referred to as piston), outer tube, etc. constituting the damping mechanism of the damper are used as they are, a damper improvement method, and a vehicle equipped with the improved damper.

[0002] More specifically, the present invention relates to an improved damper, a damper manufacturing method, and a vehicle equipped with an improved damper, in which the axial end of the outer tube that constitutes the removed pre-improvement damper is cut off, the piston built into the outer tube is pulled out, and the thin plate that constitutes the oil flow control valve (hereinafter referred to as the flow control valve) that covers the piston's oil outflow hole is replaced to exhibit the damping performance desired by the user, and then returned to its original position in the suspension. [Background technology]

[0003] Automobiles are supported by suspensions that consist of elastic means for absorbing thrust vibrations caused by uneven roads and damping means for damping the generated thrust vibrations, so that each automobile, such as a sports car, a large minivan, or a freight truck, can exhibit driving characteristics that correspond to its characteristics.

[0004] As passenger car users' preferences become more diverse, they are no longer limited to the needs regarding exterior and interior appearance, but also regarding driving characteristics, and some users are seeking driving characteristics that differ from those of commercially available passenger cars set by the automobile manufacturer. Similarly, for freight vehicles, depending on the manner in which the cargo is transported, for example, in the case of freight vehicles that only transport heavy loads at all times, some users are seeking driving characteristics that differ from those of genuine freight vehicles.

[0005] However, depending on the age and mileage of a vehicle, dampers may lose their original damping performance, causing the vehicle's driving performance to become unstable, making it necessary to restore the damping performance of the dampers. In the past, unstable driving performance was one of the reasons for replacing a vehicle. Some users would discard the dampers and replace them with new, applicable dampers in order to improve or restore the damping performance of the dampers.

[0006] In order to respond to global warming and realize a sustainable society, society is now required in all fields to make effective use of limited resources, rather than simply replacing or discarding them. Therefore, it has become necessary to improve the driving performance of automobiles so that they can respond to the diversifying tastes of users while utilizing most of the damper.

[0007] Generally, automakers make it difficult to disassemble parts installed on commercially available cars, except for parts that are designated as consumables and subject to replacement, and discourage easy modifications to cars to prevent accidents. Dampers are no exception, and even if the damping performance of a damper has deteriorated over the years of use, it has been considered difficult to restore or improve that damping performance.

[0008] Patent Document 1 discloses a technology for adjusting vehicle height using suspension parts of a target vehicle. According to the technology described in Patent Document 1, a base plate of appropriate thickness with threaded holes formed therein is placed on top of the upper mount of the suspension, and the upper mount and base plate are integrated and attached to the vehicle body using bolts of appropriate length, etc., to adjust the vehicle height.

[0009] Patent Document 2 also discloses a technology for a vehicle height setting device that uses suspension parts that are originally equipped on a vehicle. The vehicle height is set by inserting a spacer with bolts and nuts between the coil springs of the suspension installed on the vehicle body and the vehicle body. This technology is said to not deteriorate the ride comfort of the vehicle compared to methods such as replacing the original coil springs to set the vehicle height.

[0010] However, even if a damper manufactured by an automobile manufacturer is used, as in the technology described in Patent Document 1 or Patent Document 2, if the vehicle height is changed, the sensors that make up the vehicle's height detection mechanism, tilt detection mechanism, and collision prevention mechanism are likely to malfunction, which could create a new problem of affecting the driving assistance mechanism.

[0011] Patent Document 3 discloses a technique for providing a claw that can hook a dust boot even when the outer shell of a damper and a collar that forms a cylindrical body for attaching a cap are welded together. According to this technique, even if the cap is made detachable for tuning or maintenance, the lower end of the dust boot can be hooked onto the claw of the cap.

[0012] However, the technology described in Patent Document 3 is merely a technology relating to an outer shell equipped with claws for hooking the dust boot before the damper is removed, and such technology cannot be applied to a variety of vehicle models, and is not a technology that can meet the diverse driving performance needs of users.

[0013] The inventors of the present application are specialists with an extensive track record of improving the driving performance of automobiles through a variety of measures to meet the needs of users participating in car races, and have conducted extensive research into more applicable technologies, which has led to the invention of the present application.

[0014] Automobile suspension structures include independent suspension and fixed axle systems, and the suspension structure may differ between the front and rear wheels. However, the structure of the vibration damping mechanism is common to all suspension structures in that it changes damping performance by adjusting the flow rate of damper oil (hereinafter referred to as oil) using a flow control valve.

[0015] Therefore, the inventors have improved only the flow control valve among the parts of automobile suspensions, so that it is possible to meet the diverse needs of users regardless of differences in suspension structure. Furthermore, in light of the social background that requires realizing a sustainable society, the inventors have solved the needs of users by reducing the disposal of genuine parts without affecting automobile driving assistance systems. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] Tomomi No. 3144072 [Patent Document 2] Tomomi No. 3236645 [Patent Document 3] Patent Publication No. 2017-057888 Summary of the Invention [Problem to be solved by the invention]

[0017] The present invention aims to provide a damper that allows most of the damper's parts to be reused rather than discarded, that has the damping performance desired by the user so as not to cause malfunctions in the driving assistance mechanism, and that returns to the original position of the suspension, in order to realize a sustainable society. [Means for solving the problem]

[0018] A first aspect of the present invention is a damper having an outer tube that stores a damping mechanism, the outer tube having an open end at either the top or bottom end that allows the outer tube to be opened, the open end consisting of a cylindrical body and a cap, the inner surface of the cylindrical body having a first spiral groove, the periphery of the cylindrical body having a welded portion that integrates the cylindrical body and the periphery of the end, the outer surface of the cap having a second spiral groove that fits into the first spiral groove, the damping mechanism having a flow control valve that covers an oil outflow hole that connects two oil chambers, the flow control valve being any one of a group consisting of a linear damping type, a gradual damping type, and an initial damping type, and the open end is closed when the damping mechanism formed by the flow control valve is stored in the outer tube and the second spiral groove is screwed into the first spiral groove.

[0019] The inner diameter of the cylindrical body welded to the cut end of the outer tube is preferably larger than the outer diameters of all the components housed in the outer tube, but the inner diameter of the cylindrical body is not limited as long as all the flow control valves can be pulled out. The cylindrical body only needs to be welded so that oil does not leak from the open end. If the damper is a mono-tube type, the outer tube may be an outer tube on which the piston slides, or if the damper is a double-tube type, the outer tube may be an outer tube containing an inner tube on which the piston slides.

[0020] The oil outflow hole that forms the damper may be provided at the boundary between the two oil chambers that generate a damping effect by the flow of oil in and out, for example, the upper oil chamber and the lower oil chamber of the piston in the case of a single-cylinder type, or at the boundary between the upper oil chamber and the lower oil chamber in the case of a double-cylinder type, or at the boundary between the oil volume adjustment chamber between the inner and outer cylinders and the lower oil chamber.

[0021] The flow control valve is preferably configured as overlapping ring-shaped thin plates (hereinafter also referred to as shim plates) as this facilitates adjustment of the damping force, but is not limited to this, and may be configured, for example, to change the size of the oil circulation holes in the flow control valve by electronic control. According to the first invention, since only the damping mechanism of the damper that constitutes the suspension is targeted for improvement, most of the suspension parts can be reused without being discarded, and there is an advantageous effect that the vehicle height is not changed and the driving assistance mechanism is not affected, while contributing to the realization of a sustainable society and meeting user needs.

[0022] The second invention of the present invention is a damper according to the first invention, characterized in that the improved flow control valve is made up of a plurality of stacked thin plates, the thin plates are ring-shaped around the central axis of the damper and are arranged to cover the oil outflow hole, the number of thin plates is greater than the number of thin plates that make up the flow control valve before the improvement, and the response change of the damping force is smoother than that of the damper before the improvement.

[0023] The improved flow control valve only needs to cover at least a portion of the oil outflow hole and change the size of the oil outflow hole by warping the thin plate. The thickness of the thin plate is approximately 0.1 mm to 0.5 mm, and the diameter is approximately 16 mm to 38 mm, which, as with the third to fifth inventions, are generally equivalent to the thin plate that constitutes the flow control valve before the improvement. The improved flow control valve only needs to be applied so as to cover the oil outflow hole from which oil flows out, whether the tire runs over a recess in the roadway and the piston rod extends outward from the outer tube (hereinafter referred to as the "extension side") or when the piston rod retracts into the outer tube (hereinafter referred to as the "compression side").

[0024] In the second invention, the thin plates that make up the improved flow control valve are ring-shaped and attached around the central axis of the damper, and the number of plates is greater than in the flow control valve before the improvement. With the improved flow control valve for the "extension side" or "compression side" to which the second invention is applied, the stacked shim plates warp smoothly, making the response change in damping force smoother than in the damper before the improvement, and achieving the effect of changing the damping force more smoothly than in the damper before the improvement.

[0025] The third invention of the present invention is the damper of the first invention, characterized in that the improved flow control valve is made up of a plurality of stacked thin plates, the thin plates are ring-shaped around the damper center axis and are arranged to cover the oil outflow hole, the thin plates are stacked in order from the oil outflow hole toward the oil downstream, the first thin plate is arranged in contact with the oil outflow hole, at least the second thin plate and the third thin plate have a smaller diameter than but the same diameter as the first thin plate, and the damping force gradually increases compared to the damper before the improvement depending on the moving speed of the piston from the low speed range to the high speed range.

[0026] In the third aspect of the present invention, a second thin plate and a third thin plate, each having the same diameter as but smaller than the first thin plate, are stacked to form a set of thin plates with increased rigidity, and the set of thin plates suppresses warping of the first thin plate. As a result, the set of second and third thin plates suppresses warping of the first thin plate, resulting in a gradually firmer ride quality at higher speeds. Similarly, if the downstream shim plates in the set are sequentially smaller in diameter than the upstream shim plates in the set, the ride quality will become even firmer at higher speeds. The number of thin plates in the set downstream of the fourth thin plate is not limited. The ratio of the outer diameter of the thin plate in the set downstream of the oil flow to the outer diameter of the thin plate in the set upstream can be determined based on the driving characteristics desired by the user.

[0027] In the third invention, the oil flow rate is gradually increased from low speeds to high speeds in accordance with the gradual increase in the curvature of the shim plate that constitutes the flow control valve. This changes the damping force so that the ride is softer at low speeds and gradually harder at high speeds. The improved flow control valve on the "extension side" or "compression side" to which the third invention is applied has the effect of initially increasing the damping force small and gradually increasing it, regardless of the amplitude of the piston rod.

[0028] The fourth aspect of the present invention is the damper of the first aspect, characterized in that the improved flow control valve is made up of multiple stacked thin plates, the thin plates are ring-shaped around the damper center axis and are arranged to cover the oil outflow hole, the thin plates are stacked in order from the oil outflow hole toward the downstream oil flow, a first thin plate is arranged in contact with the oil outflow hole, the multiple thin plates all have the same shape, and the damping force is high from the early stage of piston movement.

[0029] In the improved flow control valve for the "rebound side" or "compression side" to which the fourth invention is applied, the multiple shim plates covering the oil outflow holes have the same diameter, so the downstream shim plate slides against the adjacent upstream shim plate, causing the upstream shim plate to warp. This makes it difficult for each shim plate to warp, suppressing the amount of oil outflow from the early stages of piston movement, resulting in a firm ride. The improved flow control valve for the "rebound side" or "compression side" to which the fourth invention is applied has the effect of increasing the damping force from the early stages of vibration generation.

[0030] The fifth aspect of the present invention is a damper according to any one of the second to fourth aspects of the present invention, characterized in that the number of the plurality of thin plates is at least 4. According to the improved flow control valve for the "extension side" or "compression side" to which the fifth aspect of the present invention is applied, since the number of thin plates is 4 or more, it is possible to smoothly change the warping of the thin plates, thereby achieving the effect of smoothly increasing the damping force.

[0031] A sixth aspect of the present invention is a method for improving a damper having an outer tube in which a damping mechanism is stored, the method comprising the steps of: a first step of cutting either the top or bottom end of the outer tube that constitutes the damper removed from the vehicle to open the outer tube; a second step of pulling the damping mechanism out of the outer tube; a third step of welding the periphery of a cylindrical body having a first spiral groove on its inner surface to the periphery of the cut end; a fourth step of replacing the flow control valve that covers the oil outflow hole connecting two oil chambers that constitute the damping mechanism with a flow control valve selected from a group consisting of a linear damping type, a progressive damping type, and an initial damping type according to the user's needs; a fifth step of inserting the damping mechanism constituted by the replaced flow control valve into the opened outer tube to store it; and a sixth step of screwing a cap that has a second spiral groove on its outer periphery that matches the first spiral groove onto the cylindrical body to close the cylindrical body.

[0032] According to the sixth aspect of the present invention, most of the parts of the damper are reused rather than discarded, and the damper can be improved to have the damping performance desired by the user so as not to cause the driving assistance mechanism to malfunction.

[0033] The seventh aspect of the present invention is a vehicle equipped with a damper according to any one of the first to fourth aspects of the present invention. According to the seventh aspect, the vehicle is equipped with a damper having an open end that can be opened. Therefore, even if the damping force of the damper deteriorates due to aging or other reasons, the original damping performance can be easily restored by replacing the thin plate. This also has the effect of enabling the vehicle to have damping characteristics that respond to changes in the user's preferences. [Effects of the Invention]

[0034] According to the first aspect of the present invention, since only the damping mechanism of the damper that constitutes the suspension is targeted for improvement, most of the suspension parts are reused rather than discarded, and the vehicle height is not changed and the driving assistance mechanism is not affected, which has the advantageous effect of contributing to the realization of a sustainable society while meeting the needs of users. The improved flow control valve for the "extension side" or "compression side" to which the second invention is applied allows the stacked shim plates to warp smoothly, making the response change of the damping force smoother than the damper before the improvement, and achieving the effect of changing the damping force more smoothly than the damper before the improvement. The improved flow control valve for the "extension side" or "compression side" to which the third invention is applied has the effect of gradually increasing the damping force, starting small and gradually increasing, regardless of the amplitude of the piston rod. The improved flow control valve on the "extension side" or "compression side" to which the fourth invention is applied has the effect of increasing the damping force from the initial stage of vibration generation. The improved flow control valve for the "extension side" or "compression side" to which the fifth invention is applied allows the warping of the thin plate to be smoothly changed, resulting in the effect of smoothly increasing the damping force. According to the sixth aspect of the present invention, most of the parts of the damper are reused without being discarded, and the damper can be improved to have the damping performance desired by the user so as not to cause the driving assistance mechanism to malfunction. According to the seventh aspect of the present invention, even if the damping force of the damper deteriorates due to aging or the like, the original damping performance can be easily restored by replacing the thin plate, and it is possible to provide a vehicle with damping characteristics that respond to changes in the user's preferences. [Brief explanation of the drawings]

[0035] [Figure 1] FIG. 1 is an explanatory diagram of a suspension structure (first embodiment). [Figure 2] FIG. 1 is an explanatory diagram of an improved mono-tube damper (Example 1). [Figure 3] FIG. 1 is an explanatory diagram of an improved twin-tube damper (Example 1). [Figure 4] FIG. 2 is an explanatory diagram of an improved flow rate adjusting valve (Example 1). [Figure 5] FIG. 10 is an explanatory diagram of the change in damping force due to the improved flow rate adjustment valve (Example 1). [Figure 6]FIG. 1 is an explanatory diagram of an improvement process for a twin-tube damper (Example 1). [Figure 7] FIG. 1 is an explanatory diagram of an improvement process for a twin-tube damper (Example 1). [Figure 8] FIG. 1 is an explanatory diagram of the damping characteristics of an improved damper for a sports car (Example 1). [Figure 9] FIG. 10 is an explanatory diagram of the damping characteristics of an improved damper for a freight vehicle (Example 2). [Figure 10] FIG. 10 is an explanatory diagram of the damping characteristics of an improved damper for a large minivan (Example 3). DETAILED DESCRIPTION OF THE INVENTION

[0036] Since there are various structures of damping mechanisms and various damping characteristics that users require from their automobile damping mechanisms, several examples of improved damping mechanisms will be shown below and the changes in damping characteristics obtained by each will be explained in order. [Example]

[0037] In Example 1, the structure and damping characteristics of an improved damper for a sports car will be described with reference to Figures 1 to 8. Figure 1(A) shows an overview of the suspension structure 1, Figure 1(B) shows an explanatory diagram of a mono-tube damper 200 before the improvement, and Figure 1(C) shows an explanatory diagram of a twin-tube damper 300 before the improvement. Figure 2 shows improved mono-tube dampers 210 and 220, and Figure 3 shows improved twin-tube dampers 310 and 320. Figures 4 and 5 show different shim plate configurations that make up the improved damping mechanism and the corresponding changes in damping characteristics. Figures 6 and 7 show the improvement process for the improved damper, and Figure 8 shows the damping characteristics for a sports car.

[0038] An automobile body 2 is supported by a tire 3 via a suspension 1. The suspension 1 comprises an elastic means such as a spiral spring 4, a spring plate 5, and a leaf spring (not shown), a damping means such as a damper 200, a cover 6 that protects a piston rod extending from the damper 200, and a bracket 7 connected to the tire 3 (see FIG. 1(A)). The damper 200 includes an outer tube 10, a piston 11, and a piston rod 12.

[0039] The piston 11 is provided with an oil outflow hole 16 through which the oil 13 sealed inside the damper flows from the upper oil chamber 14 to the lower oil chamber 15, and from the lower oil chamber 15 to the upper oil chamber 14. The oil outflow hole 16 is covered by a flow control valve 17. The outflow resistance of the oil 13 flowing between the two oil chambers 14, 15 through the oil outflow hole 16 is controlled by the configuration of the flow control valve 17, and this determines the damping characteristics of the unimproved mono-tube damper 200 (see FIG. 1(A)).

[0040] For ease of comparison, the pre-improvement mono-tube damper 200 is shown in Fig. 1(B) and the pre-improvement twin-tube damper 300 is shown in Fig. 1(C), and the damping mechanisms of the conventional mono-tube and twin-tube types will be explained. The side where the piston rod 12 fixed to the piston 11 exits the outer tube 10 will be referred to as the "extension side" (see the white arrows in Fig. 1(B) and Fig. 1(C)), and the side where the piston rod 12 enters the outer tube 10 will be referred to as the "compression side" (see the black arrows in Fig. 1(B) and Fig. 1(C)).

[0041] In the unimproved mono-tube damper 200, the piston 11 moves up and down along the inner wall of the outer tube 10. The piston is provided with an oil outflow hole 16 that allows oil to flow in both directions, from the upper oil chamber to the lower oil chamber and from the lower oil chamber to the upper oil chamber. A flexible flow control valve 17, with a shim plate 18 placed on top, covers the oil outflow side of the oil outflow hole 16, while the oil inflow side of the oil outflow hole 16 is open to allow oil to flow in (see Figure 1(B) and Figure 4).

[0042] When a tire travels over a depression in the road, it moves downward, causing the piston rod 12 attached to the vehicle body to move upward relative to the road. In other words, when the piston 11 moves "toward the extension side" (see the white arrow), the shim plate 18 covering the oil outlet hole bends, opening the oil outlet hole 16 and allowing oil to move from the upper oil chamber to the lower oil chamber. Because the volume of oil 13 inside the outer tube 10 is reduced by the amount of the piston rod 12 discharging, the lower free piston 19 rises, increasing the volume of gas 20 below the free piston by that amount. The damping resistance of the damper is determined by the outflow resistance of the oil flowing out of the flow control valve 17. The same applies to the "compression side," except that it acts in the opposite direction. Therefore, the black arrow in Figure 1(B) shows this, and its explanation is omitted.

[0043] In the twin-tube damper 300 before the improvement, an inner tube 21 is housed inside an outer tube 10, and a piston 11 moves up and down along the inner wall of the inner tube (see FIG. 1(C)). On the "extension side" of the twin-tube damper, the stacked flexible shim plates 18, similar to those of the mono-tube damper, bend, opening the oil outflow hole 16 to move oil from the upper oil chamber to the lower oil chamber, and allowing oil to flow from the oil quantity adjustment chamber 23 below the base piston 22 that covers the bottom of the inner tube to the lower oil chamber 15 (see the white arrows in FIG. 1(C)). On the other hand, on the "compression side," as shown by the black arrows in FIG. 1(C), the shim plates, which form the flow control valve, bend and open the oil outflow hole to allow oil to flow from the lower oil chamber 15 to the upper oil chamber 14, and from the lower oil chamber 15 to the oil quantity adjustment chamber 23.

[0044] Gas 20 is sealed between outer tube 10 and inner tube 21, and the volume of the gas increases or decreases depending on the increase or decrease in the oil in the oil quantity adjusting chamber. In the twin-tube type shown in FIG. 1(C), the flow control valve covering the outlet hole of the piston generates a damping force on the "extension side" (see the white arrow in the figure), and the flow control valve covering the outlet hole of the base piston generates a damping force on the "compression side" (see the black arrow in the figure). In FIGS. 1(B) and 1(C), an example of a flow control valve 17 that generates a damping force in the mono-tube and twin-tube types has been described, but it goes without saying that the present invention is not limited to this example.

[0045] The configuration of the improved damper will now be explained with reference to Figure 2. The way the damper is mounted to an automobile varies from vehicle to vehicle, and depending on the vehicle, there are cases where it is more appropriate to cut either the upper or lower end of the damper's outer tube to leave an open end, and cases where either end can be left open. First, Figure 2 shows the configuration of the improved mono-tube damper.

[0046] Figure 2(A) shows an improved mono-tube damper 210 obtained by cutting the upper end of the mono-tube outer tube, which is the piston rod protruding side, and Figure 2(B) shows an improved mono-tube damper 220 obtained by cutting the lower end of the mono-tube outer tube, which is the closed side, but either form can be used as the form of the improved damper.

[0047] Whether it is a mono-tube or a twin-tube type, the internal structure of the improved damper is the same as that of the unimproved damper, regardless of whether the upper end 211, 311 or the lower end 217, 317 is cut to form an open end, so the main parts of the improved damper structure will be explained using an example in which the upper end of the outer tube 10, which forms the piston rod protruding side of a mono-tube type, is cut (see Figure 2(A)). The upper end 211 of the outer tube 10 (see the dashed dotted line in Figure 2(A)) can be cut a predetermined length from the top end of the outer tube using a cutting tool to form an open end.

[0048] The cylindrical body 212 has an inner diameter slightly larger than the outer diameter of the outer tube 10, and a first spiral groove 213 for screwing is formed on its upper inner circumferential surface. A cap 214 closing the open end has a piston rod through-hole 215, through which the piston rod 12 slides, passing through the damper central axis, and has a second spiral groove 216 formed on its outer circumferential surface for screwing with the cylindrical body. An O-ring (not shown) prevents oil from leaking from the gap between the piston rod through-hole 215 and the piston rod 12.

[0049] In the improved mono-tube damper 210 shown in Figure 2(A), the upper end of the outer tube 10 is fitted inside the cylindrical body 212, and the cylindrical body 212 is welded all around to the outer surface of the outer tube 10. Of course, the cylindrical body may be partially welded to the outer tube, and an oil-blocking seal may be provided in the gap. Furthermore, to ensure that the outer diameter of the improved mono-tube damper remains the same as that of the damper before the improvement, the cylindrical body may be a pipe of the same diameter and thickness as the damper before the improvement, and the cylindrical body and the outer tube may be butt-welded.

[0050] The cap 214 has a plurality of locking holes 218 formed on its outer end surface to engage with a screwing tool, which assists in screwing the cap 214 into the cylindrical body 212. The screwing tool is used to screw the cap 214 onto the open end of the cylindrical body 212 to close it. In the improved single-tube damper 210 shown in Figure 2(A), a screwing tool is used to screw the cap into the cylindrical body, but of course the form of screwing is not limited as long as the cylindrical body and the cap are separable and can be easily screwed together.

[0051] In the case of the improved mono-tube damper 220 shown in Figure 2(B), in which the lower end 217 of the unimproved mono-tube damper has been cut off, it is the same as the improved mono-tube damper in which the upper end 211 has been cut off, except that there is no piston rod through-hole in the center of the cap 214. Therefore, common symbols are used in the figure and detailed explanations are omitted.

[0052] The internal structure of the improved twin-tube damper is also the same as that of the unimproved damper. The improved twin-tube damper 310, in which the upper end 311 of the outer tube forming the piston rod protruding side of the twin-tube damper shown in Figure 3(A) is cut off, is shown in Figure 2(A) which shows a mono-tube damper, and the improved twin-tube damper 320, in which the lower end 317 of the twin-tube damper shown in Figure 3(B) is cut off, is shown in Figure 2(B) which shows a mono-tube damper. Because the structures of the cylinder 212 and cap 214 are the same, the same reference numerals are used in each figure, and detailed explanations are omitted. It is sufficient for the improved damper to be returned to the original position in which the unimproved damper was installed.

[0053] The structure and operation of the improved flow control valve will be explained with reference to the cross-sectional views of the flow control valve shown in Figures 4 and 5. Figure 4 shows the structure of the improved flow control valve, and the sub-numbered figures in Figure 5 show graphs of the relationship between piston movement speed and damping force corresponding to the sub-numbered figures in Figure 4. The vertical axis of each figure in Figure 5 represents the magnitude of damping force, and the horizontal axis represents the piston movement speed. Each figure in Figure 4 shows oil flowing in the "compression side" direction (see black arrow in each figure) for the mono-tube type shown in Figure 2 and the twin-tube type shown in Figure 3. To facilitate understanding, the shim plate on the "extension side" in each figure is shown with a dashed line, and only the position of the shim plate is indicated, and explanations are omitted.

[0054] The improved flow control valve 30 on the "compression side" shown in Figure 4(A) is an improved flow control valve 30 in which six shim plates are stacked, which is more than the ring-shaped shim plates that make up the flow control valve before improvement (see Figure 1(C)). The outer diameter of each of the six shim plates is ring-shaped, with the shim plate on the downstream side of the oil that comes into contact with the piston being smaller than the shim plate on the upstream side.

[0055] The upstream shim plate covering the oil outflow hole 31 has a slightly larger outer diameter than the downstream shim plate, and the outer edge of each shim plate is warped (see Figure 4(A)). First, of the improved flow control valve covering the oil outflow hole, the outer edge of the first shim plate 32 that comes into contact with the piston warps so that oil flows out of the oil outflow hole 31 according to the moving speed of the piston that forms the damper.

[0056] When the outer edge of the first shim plate warps, the first shim plate presses against it, causing the outer edge of the second shim plate 33 to warp; when the second shim plate warps, the second shim plate presses against it, causing the outer edge of the third shim plate 34 to warp; in this way, the stacked shims warp in turn, creating resistance to oil outflow and causing the damping force to increase in proportion to the piston movement speed (hereinafter referred to as linear damping type) (see solid line A in Figure 5(A)). With a linear damping type shim plate configuration, oil easily flows out at a constant rate, resulting in a driving characteristic in which the ride comfort remains constant across the entire piston movement speed range, from low to high.

[0057] The six shim plates that make up the improved flow control valve shown in Figure 4(B) have a ring-shaped first shim plate 35 on the upstream side of the oil flow that contacts the piston, and the downstream second shim plate 36 and third shim plate 37 have the same diameter but smaller than the first shim plate. Furthermore, the further downstream fourth shim plate 38 and fifth shim plate 39 have the same diameter but smaller than the third shim plate. The sixth shim plate 40 has a smaller diameter than the fifth shim plate 39, which prevents the fifth shim plate from warping.

[0058] When the piston forming the damper moves, oil flows out of the oil outlet hole 31 in response, causing the outer edge of the first shim plate 35 that contacts the piston to warp. When the outer edge of the first shim plate warps, it is pressed by the first shim plate, causing the outer edges of the second shim plate 36 and the third shim plate 37 that are stacked on top of it to warp. Because the second and third shim plates are stacked with the same diameter, their outer edges are less likely to warp, but because they warp while sliding, the warping is smoother than that of a single shim plate with the combined thickness of the second and third shim plates.

[0059] In the early stages of piston movement, the first shim plate 35 is prone to warping, allowing oil to easily leak out, resulting in a small damping force. However, when the second and third shim plates warp, the second shim plate 36 warps while sliding against the third shim plate 37, making the overlapping shim plates less likely to warp, increasing the resistance to oil outflow and resulting in a large damping force.

[0060] The same is true when the third shim plate 37 warps, causing the fourth shim plate 38 and the fifth shim plate 39 to warp, and the oil outflow resistance increases quadratically in accordance with the piston movement speed, and the damping force also increases quadratically (hereinafter referred to as the progressive damping type) (see solid line B in Figure 5(B)). With a progressive damping type shim plate configuration, the oil flows out easily at low piston movement speeds, resulting in a soft ride, and as the piston movement speed increases, the oil flows out more easily, resulting in a harder ride.

[0061] The six shim plates 41 that make up the improved flow control valve 30 shown in Figure 4(C) are all shim plates with the same diameter. Because all shim plates 41 that cover the oil outflow hole 31 have the same diameter, each upstream shim plate warps while causing the adjacent downstream shim plate to warp, making each shim plate less likely to warp. This increases oil outflow resistance and increases damping force from the early stages of piston movement (hereinafter referred to as the initial damping type) (see solid line C in Figure 5(C)). The initial damping type shim plate configuration makes it difficult for oil to leak out from the early stages of vibration when the piston is moving at low speeds, resulting in a firmer ride.

[0062] 6 and 7, the process for converting an unimproved damper into an improved damper will be briefly described using an example in which the lower end (see FIG. 1(C)) of an unimproved twin-tube damper is cut to create an improved twin-tube damper. First, in the first step, a cutting tool is used to cut the lower end 217 (see the dashed-dotted line in FIG. 6(A)) of the outer tube 10 so as not to damage the damping mechanism housed inside the unimproved damper, and the oil 13 in the oil amount adjusting chamber 23 is drained to open the end.

[0063] The inner tube 21, which is closed by the base piston 22, is removed from the open end. The base piston 22 is removed from the inner tube 21, and the oil in the lower oil chamber 15 is drained. The piston 11 is removed from the inner tube 21, and the oil in the upper oil chamber 14 is drained, leaving the outer tube 10, inner tube 21, base piston 22, and piston 11 separated (see Figure 6(B)).

[0064] With the damping mechanism separated, a cylindrical body 212 having an open end and a spiral groove formed on its inner surface is attached to the outer surface of the outer tube 10, and the outer tube and the cylindrical body are welded together. At the same time, a cap 214 having a spiral groove formed on its outer surface and capable of being screwed onto the cylindrical body is manufactured. The base piston and the piston's unimproved flow control valve are then replaced with improved flow control valves 42, 43 configured to meet the user's needs (see Figure 7(C)).

[0065] In the flow control valve before improvement in Example 1, the flow control valve of the base piston 22 that forms the "extension side" is configured with three shim plates of the linear damping type, and the flow control valve of the piston 11 that forms the "compression side" is configured with three shim plates of the linear damping type (see FIG. 1(C)). In contrast to this, in the improved flow control valve, in order to meet the needs of users and to change the damping characteristics to those for sports cars, the flow control valve of the base piston 22 that forms the "extension side" is changed to a six-shim plate initial damping type shim plate configuration 42, and the piston side that forms the "compression side" is changed to a six-shim plate progressive damping type shim plate configuration 43.

[0066] To assemble, the piston rod 12 and the piston 11 fitted with the improved flow control valve 43 are inserted into the inner tube 21 that forms the improved damper while oil is poured into the position that will become the upper oil chamber. Next, the base piston 22 is attached to the inner tube 21 and integrated while oil is poured into the position that will become the lower oil chamber. The integrated inner tube 21 is then stored inside the outer tube 10, and while oil and gas are sealed in, the cap 214 is attached to the cylindrical body 212 to close the open end, completing the improved damper (see Figure 7(D)).

[0067] Sports car users have a need for improved cornering performance to improve times in circuit racing, gymkhana competitions, dirt trial competitions, rally competitions, and the like. Specifically, when entering a low-speed corner with a small curvature, it is necessary to make it easier for the center of gravity to move to the front of the vehicle so that the front of the vehicle sinks quickly. The change in damping characteristics to achieve this will be explained with reference to Figure 8. Figure 8(A) shows the damping characteristics on the "compression side," and Figure 8(B) shows the damping characteristics on the "rebound side."

[0068] The "compression side (see Figure 8(A))" of the dampers on all wheels is given a gradually increasing damping characteristic (see solid line B in Figure 8(A)) compared to the dampers before the improvement (see dashed line A in Figure 8(A)). Also, after entering a low-speed corner, in order to maintain a posture with the center of gravity shifted to the front of the vehicle, the "extension side (see Figure 8(B))" of the dampers is given an initial damping characteristic (see solid line D in Figure 8(B)) compared to the dampers before the improvement (see dashed line C in Figure 8(B)).

[0069] In other words, the damping characteristics for sports cars are modified to shorten the time it takes to reach the user's desired posture and to enable the posture to be maintained for a long period of time once the desired posture has been achieved, by using a gradual damping characteristic on the "compression side" of the damper and an initial damping characteristic on the "extension side" of the damper, thereby improving cornering times. [Example]

[0070] As Example 2, changes to the damping characteristics of a freight vehicle will be described with reference to Figure 9. Figure 9(A) shows the damping characteristics of the dampers before improvement for the front and rear wheels (see solid line A in Figure 9(A)), and Figure 9(B) shows the damping characteristics after improvement for the rear wheels (see solid line B in Figure 9(B)) and front wheels (see dashed line C in Figure 9(B)). In each figure, the vertical axis represents the damping force, and the horizontal axis represents the piston movement speed.

[0071] First, the dampers on commercially available freight trucks are linear damping type before improvements were made to accommodate a variety of transport modes, such as the land transport industry, where vehicles travel with heavy loads and then return empty, and the construction material transport industry, where heavy loads are transported on a daily basis (see solid line A in Figure 9(A)).For this reason, when a heavy load is loaded, the damping force tends to be insufficient, and the vehicle's running can become unstable.

[0072] Therefore, users of freight vehicles who regularly carry heavy loads need to reduce the risk of unstable driving. To meet this need, there is a need for damping characteristics that can reduce the instability of driving caused by crosswinds when cornering or traveling at high speeds, while also suppressing sudden changes in posture when returning to the original position.

[0073] In the case of a freight vehicle carrying heavy loads, it is necessary to provide a higher damping force on the rear wheels (see solid line B in Fig. 9(B)), where the load is concentrated, than on the front wheels (see dashed line C in Fig. 9(B)). For this reason, it is advisable to use initial damping types (see dashed lines A and solid lines B in Fig. 9(B)) for both the "compression side" and the "rebound side" to provide damping characteristics that make it difficult for the vehicle to tilt both front to back and side to side, and to provide damping characteristics for the rear wheels that result in a greater damping force than on the front wheels (see solid line B in Fig. 9(B)). [Example]

[0074] As a third embodiment, changes to the damping characteristics of a large minivan will be described with reference to Fig. 10. Fig. 10(A) shows the damping characteristics of the damper before improvement, and Fig. 10(B) shows the damping characteristics of the damper after improvement. In each diagram, the vertical axis represents damping force, and the horizontal axis represents piston movement speed.

[0075] Before the improvement, the dampers for large minivans had low damping force in the mid- to low-speed driving range to make the ride comfortable, and high damping force in the high-speed driving range to prevent unstable driving. Specifically, the damping characteristics on the "rebound side (see solid line A in Figure 10(A))" were linear from low to high speeds, while the damping characteristics on the "compression side (see dashed line B in Figure 10(A))" were gradually increasing.

[0076] However, there is a need to reduce the bouncy ride when driving on ordinary roads and to reduce the jolting feeling when going over road joints on highways, etc. In order to meet this need, the "compression side (see dashed line C in Fig. 10(B))" can be made an initial damping type, the damping force can be increased from low to medium speeds, and the change in damping force can be made smaller at high speeds, while the "rebound side (see solid line D in Fig. 10(B))" can remain a linear damping type, with the damping force increase gradient made larger than that of the damper before the improvement, thereby increasing the damping force across the entire speed range.

[0077] The damping force is large from low to medium speeds on the "compression side (see dashed line C in Figure 10(B))" and is also large on the "rebound side (see solid line D in Figure 10(B))." This results in damping characteristics that improve the bouncy ride quality during normal driving, reduce the change in damping force at high speeds, and reduce the feeling of being pushed up (see Figure 10(B)). (others)

[0078] The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The technical scope of the present invention is not limited to the above description, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims. ·Users have a wide range of needs for automobiles, and while typical examples are sports cars, freight cars, and large minivans, the needs are of course not limited to these. The damper with improved damping characteristics may be mounted on either the front or rear wheels only, and the manner of improvement is not limited, as a matter of course. In the above example, the improved flow control valve is explained using six shim plates, but it goes without saying that the outer diameter and number of shim plates can be determined for the flow control valve before improvement. The ring-shaped shim plate is not limited to a circular shape, but may be an elliptical or rectangular shape as long as it surrounds the central axis of the damper and covers the oil outflow hole. [Explanation of symbols]

[0079] 1...Suspension structure, 2...Vehicle body, 3...Tire, 4...Spiral spring, 5...spring receiving plate, 6...cover, 7...bracket, 10...outer tube, 11...piston, 12...piston rod, 13...oil, 14...upper oil chamber, 15...lower oil chamber, 16...oil outflow hole, 17...flow rate adjustment valve, 18...shim plate, 19...free piston, 20...gas, 21... inner tube, 22... base piston, 23... oil amount adjustment chamber, 30... improved flow control valve, 31... oil outflow hole, 32... first shim plate, 33...second shim plate, 34...third shim plate, 35...first shim plate, 36...second shim plate, 37...third shim plate, 38...fourth shim plate, 39...5th shim plate, 40...6th shim plate, 41...shim plate, 42... Initial damping type shim plate configuration, 43... Gradual damping type shim plate configuration, 200...Mono-tube damper before improvement, 210, 220...Mono-tube damper after improvement, 300...Twin-tube damper before improvement, 310,320...Twin-tube damper after improvement, 211,311...Upper end, 212...Cylinder, 213...First spiral groove, 214...cap, 215...piston rod through hole, 216...second spiral groove, 217, 317...lower end portion, 218...locking hole

Claims

1. An improved damper is an improved version of a genuine damper equipped with a damping mechanism, The damping mechanism is housed in an outer tube that constitutes the genuine damper, and includes a flow rate adjusting valve that covers an oil outflow hole connecting two oil chambers. Either the top or bottom end of the outer tube is cut off to form an open end that can be closed with a cylinder and a cap; the periphery of the cylindrical body is welded to the open end, and the inner circumferential surface of the cylindrical body is provided with a first spiral groove; the cap has a second spiral groove on its outer circumferential surface; The damping mechanism is pulled out from the open end, and the flow rate adjustment valve is replaced with an improved damping mechanism; the improved damping mechanism is inserted into the outer tube from the cylindrical body and stored therein, and then the second spiral groove is screwed into the first spiral groove, and the cylindrical body is closed by the cap; After the open end is closed, the original damper is returned to its original position. An improved damper characterized by:

2. The improved flow control valve is formed by stacking a plurality of thin plates, The thin plate is formed in a ring shape surrounding the damper central axis and is arranged to cover the oil outflow hole, The number of the thin plates is greater than the number of thin plates constituting the genuine flow control valve, The response change of the damping force is said to be smoother than the original damper.

2. The improved damper of claim 1.

3. The improved flow control valve is formed by stacking a plurality of thin plates, The thin plate is formed in a ring shape surrounding the damper central axis and is arranged to cover the oil outflow hole, The thin plates are stacked in order from the oil outflow hole toward the downstream side of the oil, a first thin plate disposed in contact with the oil outflow hole; At least the second thin plate and the third thin plate have a diameter smaller than but equal to the diameter of the first thin plate, The damping force is gradually increased compared to the original damper according to the piston's movement speed from the low speed range to the high speed range.

2. The improved damper of claim 1.

4. The improved flow control valve is formed by stacking a plurality of thin plates, The thin plate is formed in a ring shape surrounding the damper central axis and is arranged to cover the oil outflow hole, The thin plates are stacked in order from the oil outflow hole toward the downstream side of the oil, a first thin plate disposed in contact with the oil outflow hole; The plurality of thin plates all have the same diameter, The damping force is high from the initial stage of piston movement.

2. The improved damper of claim 1.

5. The number of the plurality of thin plates is at least four or more.

5. An improved damper according to any one of claims 2 to 4.

6. A motor vehicle, The improved damper according to any one of claims 1 to 4 is provided. A vehicle characterized by:

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