Self-adjusting hydraulic shock absorber

Abstract

FIELD: mechanical engineering.SUBSTANCE: self-adjusting hydraulic shock absorber comprises a cylinder, a hollow rod with a piston, a throttle and a rebound stroke safety valve, a plunger secured in the lower part of the cylinder, installed in the axial bore of the piston and forming an annular channel in the hollow rod, communicated with the above-piston cavity through radial holes in the lower part of the hollow rod and communicated with the sub-piston cavity through upper and lower radial holes in the middle part of the plunger, located on both sides of the piston, an axial channel of the plunger and a check valve installed in the upper part of the plunger. The shock absorber is equipped with a housing that forms an annular gap with the cylinder, in which a compensation chamber is located, communicated with the sub-piston cavity through a compression stroke safety valve and a check valve installed in the lower part of the cylinder. In the lower part of the plunger there is a blind axial hole and radial holes connecting the sub-piston cavity with the compensation chamber through an adjustable screw for the maximum compression stroke, installed in the lower part of the cylinder. A lower movable support is installed on the body under the lower end of the coil spring of the elastic element of the suspension, the upper end of which rests on the upper support connected to the upper end of the hollow rod.EFFECT: improves the smoothness and stability of vehicle movement.1 cl, 4 dwg

Description

[0001] The invention relates to transport engineering, namely to suspension systems for vehicles with self-regulating hydraulic resistance depending on the amplitude and direction of oscillations.

[0002] A known pneumohydraulic vehicle suspension spring comprises a cylinder housing a piston and rod, forming piston and annular cavities within the cylinder, and a hydraulic accumulator connected to the cylinder cavity via a valve, which is designed as a damping unit, self-regulating depending on the amplitude and direction of oscillations. A U-shaped plunger capable of axial movement within the valve is installed in the valve body, which has two axial holes with low resistance. The plunger has a main throttle hole with high resistance and its own unloading microvalve. At low oscillation amplitudes of the rod relative to the cylinder, the damping force is minimal, since the U-shaped plunger oscillates up and down within the valve along with the working fluid, which flows primarily through the axial holes of the housing with low resistance. However, at high amplitudes, the damping resistance increases, sinceThe plunger, in its extreme positions, rests against the ends of the housing, and the fluid flows through the main throttle opening of the microvalve with high resistance (RU Patent No. 2209735, IPC B60G 11 / 26, 2003). Thus, this device can be classified as a shock absorber with automatically adjustable resistance.

[0003] The disadvantage of the described design is that the control valve with the plunger is not located on the piston, but at the bottom of the cylinder, and attempts to increase the resistance to the rebound stroke will cause the appearance of significant vacuum above the valve, which will lead to boiling and cavitation of the shock absorber fluid, followed by a disruption in the operating mode of the device.

[0004] A self-adjusting hydropneumatic shock absorber is known, comprising a housing with a cylinder installed within it, forming an annular gap, a compensation reservoir, a piston with a hollow piston rod, installed within the cylinder and forming above-piston and below-piston cavities, a spring-loaded adjusting plunger with a thin piston rod, installed within the hollow piston rod and forming above-plunger and below-plunger cavities, as well as hard and soft springs installed outside the housing. The upper end of the hard spring rests on the housing, and the lower end on the hollow piston rod. The soft spring rests with its upper end on the hollow piston rod, and with its lower end on the thin piston rod. The annular gap communicates with the compensation reservoir through an adjustable light compression screw in the upper cover of the housing, and with the above-piston cavity through radial holes in the cylinder located above the middle position of the piston.The compensating reservoir communicates with the above-piston chamber through a check valve and an adjustable bleed screw in the upper housing cover. The above-piston chamber communicates with the below-piston chamber through the piston check valve, the piston axial bore, the above-plunger chamber, and radial holes in the hollow rod located above the plunger's mid-position. The above-plunger chamber communicates with the below-plunger chamber through channels in the plunger. When the vehicle is driving over low-amplitude bumps, only the thin piston rod and the adjusting plunger contribute to damping vibrations. They work in tandem with a soft spring to create low resistance during compression and rebound strokes. When driving over high uneven surfaces, the thin rod together with the plunger, compressing the soft spring, is pressed into the hollow rod so much that the plunger covers the radial holes of the hollow rod, as a result of which the hollow rod with the piston moves inside the cylinder and the hard spring is compressed.This provides a significant increase in the resistance force at the end of the compression stroke and the subsequent rebound stroke when the hollow rod moves up and down, which prevents the suspension from breaking through and restrains the abrupt release of the rigid spring, thereby preventing the vehicle from being thrown upward after overcoming a large unevenness (RU Patent No. 2831315, IPC F16F 9 / 50, F16F 15 / 023, 2024).

[0005] The disadvantage of this design is its high complexity, due to the presence of two sequentially arranged springs of different stiffness and two telescopically mounted hydraulic shock absorbers with different resistance levels, as well as the presence of a remote compensation reservoir. This reduces reliability and increases the size, weight, and cost of the shock absorber. Furthermore, this shock absorber has weak resistance at the end of its rebound stroke, which can lead to frequent shocks, since the soft spring, even when the shock absorber is fully extended, generates a fairly high axial force, which can exceed half the static load on the wheel.

[0006] The closest to the proposed technical solution is a shock absorber comprising a cylinder, a rod installed in the cylinder with a piston dividing the cylinder into above-piston and below-piston cavities, a compensation chamber located in the lower part of the cylinder, a throttle and compression and rebound stroke safety valves installed in the piston and communicating the above-piston and below-piston cavities with each other, a plunger secured in the lower part of the cylinder, hermetically installed in the axial bore of the piston and forming in a blind axial bore made in the rod, an annular channel communicated with the above-piston cavity through radial holes made in the lower part of the rod, and an axial channel is made inside the plunger, communicated with the annular channel through the upper check valve, and with the below-piston cavity through the lower check valve and radial holes made in the lower part of the plunger, in in the middle part of which two rows of upper and lower radial holes are made,connected to the axial channel and communicating the annular channel and the sub-piston cavity with each other (RU Patent No. 186333, IPC F16F 9 / 48, 2019).

[0007] A disadvantage of this shock absorber is its weak resistance at the end of its compression and rebound strokes, which reduces the suspension's energy capacity and can lead to bottoming out and a deterioration in ride comfort when driving over large bumps. Another disadvantage is the increased resistance in the first half of the compression stroke when the shock absorber is fully extended, which increases the vertical force on the body when the wheel exits a deep hole, thereby reducing ride comfort and limiting speed on rough roads.

[0008] The objective of the present invention is to develop a hydraulic shock absorber that provides increased ride smoothness by self-regulating resistance depending on the amplitude and direction of oscillations, eliminating a sharp bounce of the car after overcoming jumps and reducing acceleration when driving on a broken road with deep holes.

[0009] The technical result is a smooth ride of the car on the road with small irregularities and prevention of suspension breakdown when large vibrations occur.

[0010] The technical result is achieved in a self-adjusting hydraulic shock absorber comprising a cylinder, a hollow rod installed in the cylinder with a piston dividing the cylinder into above-piston and below-piston cavities, a compensation chamber, a throttle and a rebound stroke safety valve installed in the piston and communicating the above-piston and below-piston cavities with each other, a compression stroke safety valve, a plunger secured in the lower part of the cylinder, installed in the axial bore of the piston and forming an annular channel in the hollow rod, communicated with the above-piston cavity through radial holes in the lower part of the hollow rod and communicated with the below-piston cavity through upper and lower radial holes in the middle part of the plunger, located on both sides of the piston, an axial channel of the plunger and a check valve installed in the upper part of the plunger, wherein the shock absorber is provided with a housing, forming an annular gap with the cylinder, in which the compensation chamber is located,communicated with the sub-piston cavity through a compression stroke safety valve and a check valve installed in the lower part of the cylinder, in the lower part of the plunger there is a blind axial hole and radial holes communicating the sub-piston cavity with the compensation chamber through an adjustable screw of the maximum compression stroke installed in the lower part of the cylinder, and on the housing there is a lower movable support for the lower end of the coil spring of the elastic element of the suspension, the upper end of which rests on the upper support connected to the upper end of the hollow rod.

[0011] The proposed self-adjusting hydraulic shock absorber automatically adjusts internal resistance depending on the road surface. On minor uneven surfaces, resistance is minimal, while on more severe surfaces, both compression and rebound resistance increase. Furthermore, it eliminates body bounce after driving over jumps and provides a hovering effect for the wheel when hitting a pothole, preventing suspension shock during rebound travel and reducing impact on the body from the wheel when exiting a pothole.

[0012] The proposed self-adjusting hydraulic shock absorber can be applied to both ordinary civilian vehicles and sports cars.

[0013] Figure 1 shows a longitudinal section of the proposed shock absorber at rest, and Figure 2 shows a longitudinal section of the proposed shock absorber at the moment the vehicle wheel hits a high uneven surface. Figure 3 represents the moment of shock absorber operation when the wheel begins to slide off the high uneven surface. Figure 4 shows the operating diagram of a spring suspension with the proposed shock absorber.

[0014] The shock absorber is a twin-tube hydraulic shock absorber and consists of a housing 1 with a cylinder 2 installed inside it, forming an annular gap between them, in which a compensation chamber 3 is located (Fig. 1). A hollow rod 4 with a piston 5 is installed in the cylinder 2, dividing the cylinder 2 into an above-piston 6 and a below-piston 7 cavities, communicated with each other through a throttle 8 and a rebound relief valve 9 installed in the piston 5.

[0015] In the piston 5, an axial hole 10 is made, in which a plunger 11 is installed, fixed in the lower part of the cylinder 2 and forming an annular channel 12 in the hollow rod 4. The annular channel 12 is connected with the above-piston cavity 6 through radial holes 13 in the lower part of the hollow rod 4 and is connected with the sub-piston cavity 7 through the upper 14 and lower 15 radial holes in the middle part of the plunger 11, located on both sides of the piston 5, the axial channel 16 of the plunger 11 and the check valve 17 installed in the upper part of the plunger 11.

[0016] The compensation chamber 3 communicates with the sub-piston cavity 7 through the compression stroke safety valve 18 and the rebound stroke check valve 19 installed in the lower part of the cylinder 2, as well as through the adjustable maximum compression stroke screw 20, the blind axial hole 21 and the radial holes 22 made in the lower part of the plunger 11.

[0017] A thrust thread is made in the lower part of the housing 1, with the help of which a lower movable support 23 is installed under the lower end of the coil spring 24 of the elastic element of the suspension, the upper end of which rests on the upper support 25, connected to the upper end of the hollow rod 4.

[0018] The above-piston 6 and below-piston 7 cavities of the cylinder 2, as well as the cavity of the rod 4 are filled with oil, and the compensation chamber 3 with oil and gas.

[0019] The shock absorber works as follows.

[0020] When the vehicle is moving along a road with small irregularities (such as paving stones), the piston 5 makes small movements (up to 5 cm) in the cylinder 2, compressing and releasing the spring 24, the lower end of which rests on the lower support 23, and the upper end on the upper support 25 connected to the hollow rod 4. In this case, the upper 14 and lower 15 radial holes in the middle part of the plunger 11 always remain open (Fig. 1). The working fluid flows between the above-piston 6 and below-piston 7 cavities through the throttle 8, as well as through the radial holes 13 in the lower part of the hollow rod 4, the annular channel 12, the upper radial holes 14, the axial channel 16 and the lower radial holes 15 of the plunger 11 (Fig. 1). At the same time, the shock absorber resistance, determined by radial holes 14 and 15, is minimal at low speeds, which ensures highly smooth movement of the vehicle over small uneven surfaces.

[0021] When hitting a large obstacle (Fig. 2), the body 1 moves upward, compressing the spring 24, the plunger 11, installed in the axial hole 10, is recessed into the hollow rod 4, and the check valve 17 closes. In this case, piston 5 closes with its body the lower radial holes 15 in the middle part of plunger 11. After they are closed, liquid enters the above-piston cavity 6 from the hollow rod 4 through the annular channel 12 and radial holes 13, and also from the sub-piston cavity 7 through the throttle 8. In this case, the volume of oil displaced by the hollow rod 4 flows from the sub-piston cavity 7 into the compensation chamber 3 through radial holes 22, blind axial hole 21 and adjustable screw of maximum compression stroke 20. As a result, the resistance of the shock absorber increases sharply, which prevents a hard impact of the suspension parts at the end of the compression stroke.During the subsequent rebound stroke, the working fluid from the above-piston cavity 6 flows into the piston rod cavity 4 through the radial holes 13 and the annular channel 12, and also into the sub-piston cavity 7 through the throttle 8, which allows for the energy of the compressed spring 24 to be absorbed and prevents a sharp throw of the vehicle body at the beginning of the rebound stroke. In this case, the fluid from the compensation chamber 3 flows freely into the sub-piston cavity 7 mainly through the rebound stroke check valve 19, as well as through the adjustable maximum compression stroke screw 20, the blind axial hole 21 and the radial holes 22. The increased resistance of the shock absorber during the rebound stroke remains until the moment when the piston 5 opens the lower radial holes 15 in the plunger 11. With further movement of the piston 5 during the rebound stroke until the moment when the upper radial holes 14 are closed, the resistance of the shock absorber remains reduced.

[0022] When the wheel hits a deep hole (Fig. 3), under the action of the spring 24, the housing 1 moves downwards and the piston 5 closes the upper radial holes 14 of the plunger 11, as a result of which the fluid from the above-piston cavity 6 flows into the sub-piston cavity 7 through the throttle 8, which limits the downward speed of the wheel. During the subsequent compression stroke, when the wheel reaches the road surface and begins to move upward, jumping out of the hole, the piston 5 moves in the opposite direction. In this case, the fluid from the sub-piston cavity 7 enters the above-piston cavity 6 through the lower radial holes 15, the axial channel 16, the check valve 17, the annular channel 14 and the radial holes 13 with virtually no resistance.

[0023] The magnitude of the resistance force at the end of the compression stroke can be changed using the adjustable screw 20. The maximum shock absorber forces on the compression and rebound strokes are limited by safety valves 18 and 9, installed at the bottom of cylinder 2 and in piston 5, respectively.

[0024] This shock absorber design features a low-resistance compression and rebound stroke pattern in the static position and during the compression stroke from fully extended to the fully compressed position, and high-resistance at the end of the compression and rebound strokes and at the beginning of the rebound stroke from the fully compressed position (Fig. 4). This automatic change in resistance in amplitude and direction ensures a smoother ride and improved vehicle stability on rough roads. An additional advantage of this shock absorber is the ability to adjust ground clearance by moving the lower support 23 along the thread along the body 1, which expands its functionality when driving off-road or when the vehicle is loaded.

Claims

A self-adjusting hydraulic shock absorber comprising a cylinder, a hollow rod installed in the cylinder with a piston dividing the cylinder into above-piston and below-piston cavities, a compensation chamber, a throttle and a rebound stroke safety valve installed in the piston and communicating the above-piston and below-piston cavities with each other, a compression stroke safety valve, a plunger secured in the lower part of the cylinder, installed in the axial bore of the piston and forming an annular channel in the hollow rod communicated with the above-piston cavity through radial holes in the lower part of the hollow rod and communicated with the below-piston cavity through upper and lower radial holes in the middle part of the plunger located on both sides of the piston, an axial channel of the plunger and a check valve installed in the upper part of the plunger, characterized in that the shock absorber is provided with a housing forming an annular gap with the cylinder in which a compensation camera,communicated with the sub-piston cavity through a compression stroke safety valve and a check valve installed in the lower part of the cylinder, in the lower part of the plunger there is a blind axial hole and radial holes communicating the sub-piston cavity with the compensation chamber through an adjustable screw of the maximum compression stroke installed in the lower part of the cylinder, and on the housing there is a lower movable support for the lower end of the coil spring of the elastic element of the suspension, the upper end of which rests on the upper support connected to the upper end of the hollow rod.

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