RU2469224C1 - Automotive suspension adaptive damper - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: damper comprises external tube secured on rod guide, idle cylinder and working cylinder with piston secured on rod. Indirect-action controlled solenoid valve is arranged inside said tube. Valve inlet communicates with chamber composed by said working and idle cylinders. Valve outlet communicates with chamber made by idle cylinder and tube. Working cylinder piston and rod end chambers are communicated with chamber made by external tube and idle cylinder by means of bypass valves arranged in rod guide and base. Working cylinder walls have through working walls to communicate piston and rod end chambers with chamber made by working and idle cylinder. Bypass valve is arranged at lower working opening.

EFFECT: higher reliability, simplified design.

9 dwg

Description

The invention relates to mechanical engineering, in particular to hydraulic shock absorbers of vehicles, and can be used in vehicle suspensions.

Known hydraulic shock absorber of the vehicle suspension (A.I. Kuzmenko, G.M. Yaroslavtsev. Hydraulic shock absorber of the vehicle suspension. SU No. 1157292, IPC F16F 5/00 // B60C 17/04, 04/27/1983) containing a housing with workers forward and reverse cameras connected through a valve system, a compensation chamber and a rod mounted on a shock absorber element associated with the unsprung part of the vehicle, made with an axial channel and radial windows covered by a spool in the form of a spring-loaded mass, We have an inlet to the channel connecting the forward-stroke chamber with the spool device, located on the inner working surface of the housing, and the output from the spool-type device is connected by the channel to the reverse chamber.

The presence of a compression valve on the piston determines the possibility of breakdown of the shock absorber at the end of the forward stroke. And the presence of a spool device with an inertial mass makes it possible to breakdown the shock absorber at the end of the return stroke when driving along the "high-frequency profile", since in this mode the inertial mass constantly moves, periodically opening the channel between the forward and reverse cameras. Breakdown of the shock absorber, as a rule, leads to a quick failure of the shock absorber, dramatically reducing its reliability and durability.

Known adjustable shock absorber (Adjustable shock absorber. Self-study program 406. Adaptive control system for DCC chassis. Design and principle of operation, http://volkswagen.msk.ru, prototype), containing a piston rod guide on which concentrically, sequentially fixed (external) tube-tank, intermediate cylinder and working (inner) cylinder. A piston is moved inside the working cylinder, in which the piston valves are placed, and a compression valve is placed at the base of the working cylinder. The piston is mounted on a rod moving along the guide. A closed annular cylindrical channel formed by the working and intermediate cylinders, the base and the rod guide is connected on one side with a bypass hole to the working chamber 1 formed by the working cylinder, and on the other hand, with the inlet of the adjustable valve. The output channel of the adjustable valve is connected to the working chamber 2 of the shock absorber formed by the tube-reservoir, the intermediate cylinder and the rod guide. The adjustable valve is made according to the scheme of an indirect hydraulic valve with electromagnetic control. The governing body of the valve, and therefore the shock absorber as a whole, is an electromagnet, which fixes the position of the armature associated with the head of the pusher. Depending on the magnitude of the current supplied to the coil of the electromagnet, a certain position of the pusher head is established, and therefore the passage area between the pusher head and the control plate in the valve control circuit, and at the same time, the degree of damping of the shock absorber.

The disadvantages of the prototype include the fact that due to the peculiarities of its design and organization of the working process during the operation of the shock absorber, breakdowns are possible both in the compression phase and in the rebound phase, which inevitably leads to damage to the shock absorber and its subsequent failure. This circumstance sharply reduces the reliability of the shock absorber as a whole.

The disadvantages of the prototype should also include some design complexity caused by the introduction of a special Fail Safe valve into the adjustable valve circuit for the implementation of the “Fail Safe” mode, as well as the impossibility of implementing the “blocking mode” shock absorber in this design, in which the entire shock absorber turns into a single rigid link . This mode is necessary to stabilize the movement of the vehicle.

The basis of the invention is a technical problem, which consists in increasing the reliability of the shock absorber by eliminating the possibility of breakdown of the shock absorber during its operation, as well as in the implementation of the "blocking mode" and simplifying the design of the shock absorber.

This problem is solved in that in the adaptive shock absorber of the vehicle suspension, comprising an outer tube-reservoir fixed to the rod guide with annular cavities formed also in the rod guide and at the base by an intermediate cylinder and a working cylinder, inside of which a piston is mounted on the rod the working cylinder, as well as containing an adjustable solenoid valve of indirect action installed in the tube-tank, including sequentially placed in the main damper valve with a central throttle bore, pressed against the inner surface of the solenoid valve by a spring, and a direct-acting control valve rigidly connected to the armature of the control electromagnet, the inlet of the adjustable solenoid valve of indirect action is connected to the cavity formed by the working and intermediate cylinders, and the outlet - with a cavity formed by an intermediate cylinder and a tube - a reservoir, the over-piston and under-piston cavities of the working cylinder are connected through the bypass valves installed respectively in the rod guide and in the base, according to the invention, in the walls of the working cylinder, in its upper and lower parts, through working windows are made, connecting through respectively , an over-piston and under-piston cavity of the working cylinder with a cavity formed by the working and intermediate cylinders, while the bypass valve is installed on the lower working window, and the piston is made in one piece, rum, the head of the control valve is made of direct action in the form of a cone that closes the part of the smaller diameter disk restrictive.

The invention is illustrated by drawings, where figure 1 shows a diagram of a shock absorber in the compression phase; figure 2 - diagram of the shock absorber in the end phase; figure 3 - diagram of the shock absorber at the initial moment of the compression phase; figure 4 - diagram of an adjustable solenoid valve; figure 5 (a, b, c, d, d, e, f, h) - some options for the possible implementation of the form of working windows (view. A); figure 6 is a qualitative picture of the dependence of the cross-sectional area F of the working window on the height h of the lumen of the working window when the piston overlaps the working window when the piston approaches the boundary of the working area; Fig.7 option of the possible implementation of the cross-sectional shape of the working window; on Fig is a graph of the magnitude of the annular gap Z in the bore of the control valve on the value I of the control current in an adjustable solenoid valve; figure 9 is a working characteristic of the shock absorber in various adjustment modes.

.The shock absorber consists of a concentrically arranged outer tube-tank 1, an intermediate cylinder 2 and a working cylinder 3, which are mounted on top of the guide 4 of the rod 5 connected to a monolithic (not containing valves or throttles) piston 6. The piston 6 is movably mounted in the working cylinder 3, which together with the intermediate cylinder 2 is fixed to the base 7. The tube-tank 1 is closed from below by a cover 8. In the lower part of the guide 4 there is a bypass valve 9, made, for example, in the form of an elastic plate of low rigidity. A similar bypass valve 10 is placed on the lower working window 11, which limits the extreme lower position of the piston 6. At the base 7, a similar bypass valve 12 is also provided, blocking the inlet window 13. The working cylinder 3 forms an annular cavity 14 with the intermediate cylinder 2, which, with on the one hand, through the upper working window 15 communicates with the nadporshnevaya cavity 16, and on the other, through the channel 17, with the inlet 18 of the adjustable electromagnetic valve 19. The working window (both upper 15 and lower 11) can m be formed as a through hole defined profile (5) or the hole with variable cross section (Figure 7), the inner surface 20 which has the same profile and the outer surface 21 may have a circular shape. The profile of the working windows 11 and 15 is symmetrical with respect to each other. The thickness H of the piston 6 should be greater than the height H _{1 of the} working windows:

.

The outer tube-tank 1 together with the intermediate cylinder 2 forms an annular cavity 22, which is connected through the channel 23 to the outlet 24 of the adjustable solenoid valve 19. The shock absorber is attached to the corresponding vehicle suspension elements using nodes 25 and 26 (for example, eyes).

The adjustable solenoid valve 19 in functional design is a hydraulic valve of indirect operation with electromagnetic control. It includes a main valve (locking and regulating element) - a shutter 27, which is pressed by the action of a spring 28 with an annular surface 29 to an annular surface 30 of an adjustable solenoid valve 19. In the center of the shutter 27 there is a throttle hole 31 of small diameter. The movement of the main valve - flap 27 is controlled by a control valve 32 - a small direct-acting valve, which is pressed from the control plate 33 of the valve 19 by a spring 34. The head (left end) of the control valve 32 is made in the form of a cone 35, which is closed from the smaller diameter by the restrictive disk 36.

The control valve 32 is rigidly connected to the armature 37 of the electromagnet, to the contacts 38 of which and, further, the control current I is supplied to the coil 39.

An axial groove 40 is made on the outer surface of the armature 37, by means of which the cavities 41 and 42 communicate with each other. The annular cavity 14 with the open valve 10 can communicate through the window 11 with the piston cavity 43. The cavities 22, 14, 16 and 43 are filled with oil.

The shock absorber works as follows.

In the compression phase, when the rod 5 and the piston 6 are moved down, as shown in FIG. 1, the oil opens the valve 10 under the pressure of the piston and is displaced through the working window 11 into the annular cavity 14, making up for the increasing volume of the cavity 16 due to the presence of the working window 15. this part of the oil corresponding to the volume of the rod 5 sliding into the cavity 16, enters through the channel 17 into the inlet 18 and then into the inlet cavity of the adjustable solenoid valve 19, then bypassing the annular gap of width X between the annular surface 29 of the shutter 27 and the annular th surface 30 of the adjustable solenoid valve 19 - into the output cavity 44 of the adjustable solenoid valve 19.

Due to the presence of the working window 15, the oil pressure in the cavities 43 and 16 is almost the same and significantly greater than in the cavity 22, which is connected via the channel 23 to the outlet 24 of the adjustable electromagnetic valve 19. For this reason, the bypass valve 12 is closed during the compression phase.

The cross-sections of the throttle hole 31 and the annular channel between the cone 35 and the control plate 33 are selected commensurate with each other. Therefore, the oil flow rate through the throttle hole 31 and the annular channel between the cone 35 of the control valve 32 and the control plate 33 are also comparable. As a result, the oil pressure in the cavity 45 is less than in the inlet cavity (inlet 18) of the electromagnetic valve 19, and the stiffness of the spring 28 is selected such that the oil pressure force N ₁₈ from the inlet side 18 is balanced by the combination of the oil pressure force N ₄₅ from the cavity 45 and force N ₂₈ spring elasticity 28:

As a result, the shutter 27 occupies a position in which an annular gap X is formed between the annular surfaces 29 of the shutter and 30 of the valve 19. In this case, the bulk of the oil, overcoming the hydraulic resistance in the annular gap X, enters from the cavity 44 through the outlet 24 of the valve 19 and the channel 23 into the annular cavity 22 of the shock absorber.

It has been established that the level of damping of the shock absorber is determined precisely by the value of hydraulic resistance noted in the annular gap X.

An insignificant amount of oil, corresponding to a very small (compared with the inlet 18) flow rate through the throttle hole 31, enters the cavity 45 and then through the annular gap Z between the control plate 33 and the cone 35 of the control valve 32 into the cavity 41, and through the control channel 46 and the cavity 44 - also in the outlet 24 of the valve 19.

This process continues until the lower end plane 47 of the piston 6 reaches position II (corresponding to the level of the upper boundary of the working window 11), at which the working window 11 is still fully open to a height of H ₁ . With further movement of the piston downward, the working window 11 begins to gradually overlap with the piston 6, i.e. the height h of the lumen of the working window begins to decrease from the value of H ₁ to 0, and the area F of the cross section of the working window - from the value of F _max to 0 (Fig.6).

We emphasize that when the plane 47 of the piston 6 reaches position II-II, the working window 11, due to (1), is completely closed, i.e.

In this case, the further movement of the piston down, due to the incompressibility of the oil, is impossible. This eliminates the possibility of breakdown of the shock absorber at the end of the compression phase, i.e. the possibility of collision of the plane 47 of the piston 6 with the base 7 with a sharp compression of the shock absorber, which may occur, for example, when the vehicle moves at high speed on an uneven road, in particular, when the wheel hits a hummock.

Thus, the position II-II of the plane 47 of the piston 6, corresponding to the lower edge of the working window 11, determines the lower boundary position of the piston 6.

It should be noted that during the entire compression phase, except for its initial moment, the bypass valve 9 is closed, since the oil pressure in the cavities 16, 43 and 14, i.e. in the inlet 18 of the adjustable solenoid valve 19, more than in the cavity 22, which is connected to the outlet 24 of the adjustable solenoid valve 19. For the same reason, the bypass valve 12 is always closed during the entire compression phase.

In the rebound phase, when the rod 5 and piston 6 are moved upward, as shown in FIG. 2, oil is displaced from the cavity 16 by the piston 6 through the working window 15 into the cavity 14 and then passes through the channel 17 to the inlet 18 of the adjustable electromagnetic valve 19. Subsequent the oil path is the same as in the previous compression phase. The only difference is that due to the occurrence of some vacuum in the sub-piston cavity 43, the bypass valve 12 opens and the increase in oil volume in the sub-piston cavity 43 is compensated by its flow through the inlet 13 from the cavity 22, which is connected to the outlet 24 of the adjustable solenoid valve 19. Since the oil pressure in the cavity 16 (i.e., in the inlet 18 of the adjustable solenoid valve 19) is significantly greater than in the cavity 22 (which is connected to the outlet 24 of the adjustable solenoid itnogo valve 19), the bypass valve 9 during the entire closed-clear phase.

The process described above is repeated until the upper plane 48 of the piston 6 reaches position III-III (corresponding to the level of the lower boundary of the working window 15), at which the working window 15 is still fully open to a height of H ₁ . With further movement of the piston upward, the working window 15 (similar to that which occurred in the compression phase) begins to gradually overlap with the piston 6, i.e. the height h of the lumen of the working window begins to decrease from the value of H ₁ to 0, and the area F of the cross section of the working window - from the value of F _max to 0 (Fig.6).

We emphasize that when the plane 48 of the piston 6 reaches position IV-IV, the working window 15, due to (1), is completely closed, i.e. relation (3) holds. In this case, further movement of the piston upwards, due to the incompressibility of the oil, is impossible. This eliminates the possibility of breakdown of the shock absorber at the end of the rebound phase, i.e. excludes the possibility of collision of the plane 48 of the piston 6 with the guide 4 of the rod with a sharp stretching of the shock absorber, which may occur, for example, when the vehicle moves at high speed on rough roads, in particular, when the wheel enters the road pit.

Thus, the position IV-IV of the plane 48 of the piston 6, corresponding to the upper face of the working window 15, determines the upper boundary position of the piston 6.

Consider the very initial moment of movement of the piston 6 in the compression phase from the extreme upper position, when its plane 48 still occupies the position IV-IV (figure 3). At this point, a certain rarefaction is created in the cavity 16, under the action of which the bypass valve 9 opens and the increase in the volume of the cavity 16 is compensated by the influx of oil through the window 49 from the cavity 22. But this situation occurs only at the indicated moment, avoiding the gap in the continuity of the volume of oil in the cavity 16. At subsequent times, oil will enter the cavity 16 through the opening window 15 as described in the analysis of the operation of the shock absorber in the compression phase.

It must be borne in mind that to prevent air from entering cavity 16, the oil level in the shock absorber must not be lower than the position indicated by the cross section V-V.

Note that choosing one or another form of working holes 11 and 15, it is possible to form one or another law of movement of the piston as it approaches the extreme positions II-II and IV-IV. In particular, choosing in the window 15 the shape corresponding to Figure 5, and in FIG. 5, a smoother decrease in the cross-sectional area F of the working window can be realized (curve 6.1. In FIG. 6), and therefore, a smoother increase in the shock absorber resistance, i.e. e. more effective damping of dynamic loads in the vehicle suspension.

It should be noted that in both of the two phases discussed above, in the compression phase and the rebound phase, the shock absorber, with a constant control action from the control unit 50 to the adjustable solenoid valve 19, which is carried out in the form of a control current I supplied to contacts 38 ( the control valve 32 remains stationary) of the coil 39, i.e. under the condition

I = Const

works like conventional well-known non-adjustable shock absorbers. In this case, the throttle mode is implemented due to a special selection and profiling of the shape of the working holes 15 and 11, and the valve mode is due to the appropriate selection of the stiffness of the spring 28 of the shutter 27: with increasing piston speed, i.e. as the oil pressure increases in the inlet 18 of the electromagnetic valve 19, the shutter 27 automatically moves to the right, increasing the annular gap X between the annular surfaces 29 and 30. The latter circumstance leads to an increase in oil flow through the annular gap X of the main valve and, as a result, to a decrease the resistance force of the shock absorber, to reduce its degree of damping.

Thus, the adjustable solenoid valve 19, with a constant control action from the side of the control unit 50, works like a regular unloading valve in a conventional unregulated shock absorber. One of these operating modes of the electromagnetic valve 19, corresponding to the case

shown in figure 4: if the control current I on the contacts 38 is zero, then the armature 37 under the action of the spring 34 occupies the extreme right position, limited, for example, by the stop 51. In this case, the flow of oil flowing through the control channel 46 is determined by the annular gap Y between the stop disc 36 and the control plate 33, as in this position (as will be shown below)

Here Z is the annular gap in the flow section of the control valve 32 is the gap between the conical surfaces 52 and 53 of the cone 35 and the control plate 33, respectively.

Note that mode (4), known as the Fail Safe mode (emergency movement program), is one of the standard shock absorber operating modes. It occurs, for example, when the control unit 50 fails.

It should be noted that the proposed shock absorber, in contrast to the case considered above (4), allows in a wide zone, depending on road conditions, to adjust its performance - the dependence of the force P on the rod on the value of the rod velocity V (Fig. 9):

Those. in terms of functionality, it is an adaptive shock absorber.

This is ensured by external action from the side of the control unit 50 by changing the magnitude of the control current I on the contacts 38 of the coil 39. We will consider these more general modes of operation of the shock absorber when the control current I is applied to the contacts 38 of the coil 39 from the control unit 50, i.e. . consider cases when

In these cases, the anchor 37, and therefore the control valve 32, begins to act additional electromagnetic force N ₁ , which should be equal to the resultant of all the forces acting on it:

Here: N ₄₅ - oil pressure force from the side of the cavity 45 to the valve 32; N ₄₁ - the pressure force of the oil from the side of the cavity 41 to the valve 32; N ₃₄ - spring force 34.

When the value of the control current I increases, the electromagnetic force N ₁ (the left side of equality (8) also increases by the corresponding value. This leads to a certain displacement of the control valve 32 to the left along the axis. The latter, in turn, causes compression of the spring 34 and, therefore, leads to an increase values of force N ₃₄ until the right-hand side of equality (8) increases by a similar amount, while equality (8) is restored again.

Thus, with an increase in the value of the control current I at the contacts 38 of the coil 39, the control valve 32 moves to the left along its axis, and the annular gap Z in the passage section of the control valve decreases (Fig. 8). A decrease in the annular gap Z automatically causes a decrease in the oil flow through it and, as a result, an increase in the oil pressure in the cavity 45 and the corresponding force N ₄₅ (the right-hand side of equality (2) increases). But this circumstance causes the flap 27 to shift to the left along its axis (unloading spring 28), at the same time (proportionally) reducing the value of elasticity force N _{28 of} spring 28 just so that equality (2) is restored again. At the same time, the leftward movement of the shutter 27 causes a decrease in the annular gap X, i.e. an increase in the hydraulic resistance of the electromagnetic valve 19, and therefore an increase in the degree of damping of the shock absorber.

Thus, with increasing value of the control current I at the contacts 38 of the coil 39, the degree of damping of the shock absorber also increases.

It should be noted that the implementation of the main working surface of the control valve 32 in the form of a conical cylindrical surface 52, which is closed from the smaller diameter by the restrictive disk 36, on the one hand, helps to reduce the axial dimensions of the valve, and on the other hand, expands the possibilities of varying the operating characteristics of the valve due to the possibility of varying an additional parameter - the angle of inclination of the conical cylindrical surface 52. The presence of the restrictive disk 36 allows you to exclude from The additional special Fail Safe valve required in the prototype for the implementation of the “Fail Safe” mode, which helps simplify the design.

We emphasize that the "technological" range

in real constructions it is not advisable to use because of inevitable errors.

The value of the control current I = I ₁ corresponds to the operation of the shock absorber in the mode of "low degree of damping" (mode "Comfort") - curve 1 in Fig.9. This mode is in demand when driving on bad roads.

The value of the control current I = I ₂ corresponds to the operation of the shock absorber in the "normal degree of damping"("Normal" mode) - curve 2 in Fig.9. This mode is in demand when driving in normal road conditions.

The value of the control current I = I ₃ corresponds to the operation of the shock absorber in the mode of "high damping" (mode "Sport") - curve 3 in Fig.9. This mode is in demand when driving at high speeds on good roads.

Note that (Fig. 8)

0 <I ₁ <I ₂ <I ₃ <I _max , and at the same time 0 <Z ₃ <Z ₂ <Z ₁ <Z _max .

It is interesting to note that the proposed shock absorber, in contrast to the known ones, also allows for the implementation of a “blocking mode”

I = I _max → Z = 0,

at which the annular gap Z is equal to zero. In this case, the oil pressure in the cavities of the inlet 18 and 45 is equalized and the shutter 27 under the action of the spring 28 occupies the extreme left position. In this case, the annular surface 29 of the shutter 27 is pressed against the annular surface 30 of the electromagnetic valve 19 and as a result, the annular gap X becomes equal to zero:

I = I _max → Z = 0 → X = 0.

The inlet 18 of the solenoid valve 19 is blocked and the movement of the piston and rod are blocked. The locking mode is necessary, for example, to stabilize the movement of the vehicle in corners, during rolls, as well as during sharp braking and acceleration - i.e. when "pecking" the vehicle.

In conclusion, we note that for regime (4), as already noted, relation (5) holds. Clarify it. In practice, the value of Y, it is advisable to choose from the condition (Fig)

Then, taking into account (10) in the interval (9), function (6) will graphically have the form 8.1 (Fig. 8).

Thus, the use of the proposed design solution of the shock absorber will increase its reliability and durability by eliminating the possibility of breakdown of the shock absorber during its operation, simplify and, therefore, reduce the cost of the design by eliminating the special Fail Safe valve for implementing the “Fail Safe” mode, and expand the shock absorber’s functionality for due to the possibility of implementing a blocking mode.

Claims (1)

Adaptive shock absorber of a vehicle suspension, comprising an outer tube-tank fixed to the rod guide with annular cavities formed also in the rod guide and in the base by an intermediate cylinder and a working cylinder, inside of which a piston is fixed to the rod, which is moved in the working cylinder, and also contains in the tank tube, an adjustable solenoid valve of indirect action, which includes the main damper valve in series with the central throttle aperture, pressed against the inner surface of the solenoid valve by a spring, and a direct-acting control valve, rigidly connected to the armature of the control electromagnet, the inlet of the adjustable solenoid valve is connected to the cavity formed by the working and intermediate cylinders, and the outlet is connected to the cavity formed by the intermediate cylinder and a tube-reservoir, the supra-piston and sub-piston cavities of the working cylinder are connected to the cavity formed by the outer tube-reservoir m and an intermediate cylinder, bypass valves installed respectively in the rod guide and at the base, characterized in that in the walls of the working cylinder, in its upper and lower parts, through working windows are made connecting respectively the over-piston and under-piston cavities of the working cylinder, formed by the working and intermediate cylinders, while the bypass valve is installed on the lower working window, and the piston is made monolithic, in addition, the head of the direct-acting control valve it is filled in the form of a cone that closes on the side of a smaller diameter with a restrictive disk.

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