JPH1163076A - Solenoid control device, and solenoid control device for controlling damping force characteristic of shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform optional characteristic opening degree control for a specified control signal by non-linearly changing the on-duty ratio of a driving current for an opening degree control signal in the suspension device of a vehicle. SOLUTION: The non-linearity of a generated clamping force characteristic for the on-duty ratio (%) of a driving current for a solenoid coil 68 is corrected by the non-linearity compensation map of an on-duty ratio (%) variable characteristic for a control signal, and thereby the linearity of a damping force variable characteristic for the control signal is secured, and thus a control effect is increased. Also, since many of magnetic fluxes generally flow near the surface of a magnetic member, one having thin plates stacked has a total magnetic flux amount larger than that of an integral one even in an equal section area, and by using the specified number of stacked magnetic flux plates 74 each having a specified thickness, a weight is reduced, and the responsiveness of each of a damping force variable mechanism 31 and a suspension system is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid valve control device driven by a solenoid and a solenoid valve control device for controlling damping force characteristics of a shock absorber.

[0002]

2. Description of the Related Art Conventionally, as an electromagnetic valve control device driven by a solenoid for variably controlling a damping force characteristic of a shock absorber, for example, Japanese Patent Laid-Open Publication No. 3-153412, "Suspension control for continuously changing the damping force characteristic" has been proposed. Such methods are known.

In this conventional suspension control method, PWM control is performed on a solenoid valve that switches a damping force switching valve,
Switching between the high damping force state and the low damping force state at high speed, and adjusting the ratio (on-duty ratio) between the time of the high damping force state and the time of the low damping force state, the intermediate damping force state is obtained. It was made up.

[0004]

However, in the conventional suspension control method, the on-duty ratio is variably set proportionally (linearly) with respect to the vehicle body fluctuation value. There was a problem. That is, in general, the damping force changed by the solenoid valve is generated non-linearly with respect to the on-duty ratio of the drive current to the solenoid, so that the damping force control suitable for the vehicle body behavior cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has an electromagnetic valve control device capable of controlling an opening degree of an arbitrary characteristic with respect to a predetermined control signal;
An object of the present invention is to provide an electromagnetic valve control device for controlling a damping force characteristic of a shock absorber, which can perform damping force characteristic control of an arbitrary characteristic with respect to a damping force characteristic control signal.

[0006]

According to a first aspect of the present invention, there is provided a solenoid valve control apparatus, comprising:
In the solenoid valve control device configured to perform the opening control of the solenoid valve by variably controlling the on-duty ratio of the driving current to the solenoid valve by the M control, the on-duty ratio of the driving current to the opening control signal is nonlinear. It is a means to change it.

According to a second aspect of the present invention, there is provided an electromagnetic valve control apparatus for controlling a damping force characteristic of a shock absorber, wherein the on-duty ratio of a drive current to the damping force characteristic variable control electromagnetic valve is variably controlled by PWM control to thereby make the damping force characteristic variable. In the electromagnetic valve control device for controlling the damping force characteristic of the shock absorber configured to perform the opening control of the control electromagnetic valve,
The on-duty ratio of the drive current to the damping force characteristic control signal is nonlinearly changed.

[0008]

In the solenoid valve control device according to the first aspect of the present invention, the on-duty ratio of the drive current with respect to the opening control signal is changed non-linearly, so that the predetermined control signal
It becomes possible to control the opening degree of any characteristic.

Further, in the electromagnetic valve control device for controlling the damping force characteristic of the shock absorber according to the second aspect, the on-duty ratio of the drive current with respect to the damping force characteristic control signal is changed non-linearly. Damping force characteristic control of an arbitrary characteristic can be performed on the force characteristic control signal.

[0010]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration explanatory view showing a vehicle suspension system according to an embodiment of the present invention to which an electromagnetic valve control device for controlling a damping force characteristic of a shock absorber is applied, and is interposed between a vehicle body and four wheels. , Four shock absorbers SA _FL , SA _FR , SA _RL , SA _RR (in the description of the shock absorbers, when these four are collectively referred to, and when describing their common configuration, they are simply indicated as SA. In addition, the code at the lower right indicates the wheel position, _FL indicates the front wheel left, _FR indicates the front wheel right, _RL indicates the rear wheel left, and _RR indicates the rear wheel right.) Then, the acceleration G in the vertical direction (G _FL , G
_FR , _GRL , _GRR ) sprung vertical acceleration sensor (hereinafter referred to as vertical G sensor) 1 ( _1FL , _1FR , _1RL ,
1 _RR ), and a signal from each of the upper and lower G sensors 1 (1 _FL , 1 _FR , 1 _RL , 1 _RR ) is input to a position near the driver's seat, and each of the shock absorbers SA _FL , SA _FR , S
A _RL , SA _RR each extension stroke side damping force variable mechanism 31 described later
A control unit 4 for outputting a drive signal to the pressure-stroke-side damping force variable mechanism 33 is provided.

FIG. 2 is a system block diagram showing the above configuration. The control unit 4 includes an interface circuit 4a, a CPU 4b, and a drive circuit 4c, and the interface circuit 4a includes the upper and lower G sensors 1 (1).
_FL , 1 _FR , 1 _RL , 1 _RR )
_FL , G _FR , G _RL , G _RR ) signals are input, and in the control unit 4, based on these input signals, each shock absorber SA (SA _FL , SA _FR , SA _RL , SA _RR ).
Is performed.

The control unit 4 includes:
The damping of each shock absorber SA based on the sprung vertical acceleration G (G _FL , G _FR , G _RL , G _RR ) signal from each of the vertical G sensors 1 (1 _FL , 1 _FR , 1 _RL , 1 _RR ). A signal processing circuit for obtaining a control signal V used for force characteristic control (FIG. 1)
0) is provided. The details of this signal processing circuit will be described later.

Next, the structure of the shock absorber SA will be described with reference to FIGS. 3 is an overall sectional view showing a shock absorber SA, FIG. 4 is an enlarged sectional view showing a later-described extension side variable damping force mechanism, and FIG. 5 is an enlarged sectional view showing a piston section described later.

As shown in FIG. 3, the shock absorber SA is slidably provided with a cylinder 21 filled with hydraulic fluid and an upper chamber 21a and a lower chamber 21b defined inside the cylinder 21. A piston 24, an outer cylinder 23 forming a reservoir chamber 23a on the outer periphery of the cylinder 21, a base 24 defining a lower end of the cylinder 21 between the lower chamber 21b and the reservoir chamber 23a, and provided on the base 24. The piston 22 is fixed to a lower end of the check passage 24a that allows only the flow from the reservoir chamber 23a to the lower chamber 21b, the check passage 24c that allows only the flow from the lower chamber 21b to the reservoir chamber 23a. The piston rod 25 guides the sliding of the piston rod 25, and the upper end of the cylinder 21 extends between the upper chamber 21a and the reservoir chamber 23a. Guide member 26 which defines the
And an upper communication path formed between the cylinder 21 and the outer cylinder 23 to form an upper annular flow path 28a between the upper peripheral surface of the cylinder 21 and the upper chamber 21a and the upper communication hole 21c. A lower annular flow path 29a is provided between the cylinder 28 and the cylinder 21 and the outer cylinder 23 and communicates with the lower chamber 21b through the lower communication groove 24b between the cylinder 21 and the lower outer peripheral surface of the cylinder 21. As shown in detail in FIG. 4, the lower communication cylinder 29 forms an extension-side communication channel 31 a communicating between the upper annular channel 28 a and the reservoir chamber 23 a, and forms the extension-side communication channel 31 a. A variable stroke-side damping force mechanism 31 for variably controlling the flow amount, and a check flow path 32 that allows only the flow from the reservoir chamber 23a to the upper annular flow path 28a by bypassing the variable stroke-side damping force mechanism 31. And also the figure As shown in detail, a pressure-side communication flow path 33a that communicates between the lower annular flow path 29a and the reservoir chamber 23a is formed, and a pressure-stroke-side damping force that variably controls the flow rate of the pressure-side communication flow path 33a. A variable mechanism 33;
A check flow path that allows only the flow from the reservoir chamber 23a toward the lower annular flow path 29a, bypassing the pressure stroke side damping force variable mechanism 33;

As shown in detail in FIG. 5, the piston 22 restricts only the flow from the upper chamber 21a to the lower chamber 21b by the expansion disk valve (extension high damping valve) 22a. The expansion side communication hole 22b, which generates a high damping force by allowing the pressure, and the compression side disc valve (pressure side high attenuation valve) 22c allow only the flow from the lower chamber 21b to the upper chamber 21a in a limited manner. A pressure-side communication hole 22d for generating a damping force is provided.

Next, the structure of the extension stroke side damping force variable mechanism 31 will be described in detail with reference to FIG. The outer cylinder 23
One end of an annular base 51 is fixedly welded to the opening formed in the opening, and a valve body 52 is fastened and fixed to the other end of the opening end surface side with a bolt 53 so as to close the opening end surface.

On the other hand, an opening formed in the upper communication cylinder 28 at the coaxial position in the base 51 is provided with a joint 5.
4, one end of the guide tube 56 is press-fitted and connected to the inner peripheral side of the other end of the joint 54 via a seal ring 55. Further, the other end of the guide tube 56 is The inner protruding portion 52a of the valve body 52 is press-fitted and fixed, whereby the space between the upper annular flow passage 28a and the reservoir chamber 23a is
Is defined via the.

One end opening of a casing 57 is fastened and fixed to the outer surface side of the valve body 52 by the bolt 53. A space between the inside of the casing 57 and the reservoir chamber 23a is formed on the outer peripheral side of the valve body 52. Communication hole 5
2b is always in communication.

A small-diameter portion of one end of the stator 58 is inserted from the outside toward the inside of the shaft hole of the valve body 52. That is, the coil case 59, the collar 60,
The (extension side) variable damping force variable disc valve 61, valve body 52, (extension side) check valve 62, and collar 63 are sequentially mounted, and finally fastened with a nut 64 to assemble each member. The reservoir body 23a is connected to the valve body 52 through a communication hole 52b.
By opening the (expansion side) check valve 62 from the inside of the casing 57 which is always in communication with the flow path, the flow in the direction of the upper annular flow path 28a is secured (extension side).
2 and a (growing-side) communication flow path 31a that secures a flow in the casing 57 by opening the (growing-side) variable damping force disc valve 61 from the upper annular flow path 28a.

A pilot pressure chamber 65 is formed in the stator 58 so as to penetrate the axis thereof, and a lower end opening of the pilot pressure chamber 65 has an upper annular passage 28a.
A pilot bush 66 having a small hole 66a formed therein for restricting the flow rate of the hydraulic fluid flowing into the pilot pressure chamber 65 is press-fitted. Further, a filter 67 for preventing foreign matter (such as contamination) from entering the pilot pressure chamber 65 is incorporated in the nut 64.

A solenoid coil 68 and a coil assist plate 69 made of a non-magnetic material are accommodated between the outer peripheral surface of the large diameter portion of the stator 58 and the coil case 59.
A mold material 71 integrally formed of a non-magnetic material such as a resin is also housed between the outer peripheral surface on the distal end side of the coil case 59 and the casing 57 to also fix the harness 70. The cover 72 is accommodated in a state in which the cover 72 is in contact with the mold material 71 and the end opening end surface of the coil case 59, and is fixed by bending the end opening edge of the casing 57 inward and caulking.

On the large-diameter end face of the stator 58, a valve seat 58a with which the pilot valve 73 contacts is formed so as to protrude. As shown in detail in FIG. 6, the pilot valve 73 is formed by punching out a single thin plate made of hard spring steel, thereby forming one connection between the outer peripheral fixed portion 73a and the inner peripheral movable portion 73b. It is formed in a structure connected by the portion 73c. The pilot valve 73 is assembled in such a manner that the inner peripheral movable portion 73b abuts on the valve seat 58a without load by fixing the outer peripheral fixing portion 73a between the coil assist plate 69 and the cover 72. Have been.

A recess 72a is formed on the inner surface of the cover 72 facing the movable portion 73b of the pilot valve 73, and a disc 72 is formed in the recess 72a while being laminated on the inner peripheral movable portion 73b. A magnetic flux reinforcing plate 74 is housed in a floating manner. As shown in detail in FIG. 6, the magnetic flux reinforcing plate 74 is made of an iron material (ferromagnetic material) having a smaller carbon content than the constituent material of the pilot valve 73.
A cutout portion 74a is formed in the outer peripheral portion to form a flow path for the working fluid so that the movement in the recess 72a can be performed smoothly.

The magnetic flux reinforcing plate 74 includes the pilot valve 73, the stator 58, and the coil case 59.
And the cover 72 together with the cover 72 to form a magnetic path when energizing the solenoid coil 68.

The coil assist plate 69, the coil case 59, and the molding material 71 are formed with a return flow path 75 that communicates between the inside of the recess 72a and the inside of the casing 57.

An assist ring 76 for assisting the valve closing force and forming a back pressure chamber 77 is slidably provided on a base outer peripheral surface of the coil case 59 via a sliding seal member 76a. I have. This assist ring 76
The inner opening end face protruding inward is brought into contact with the outer peripheral edge of the rear surface of the variable damping force disk valve 61, so that the inside of the casing 57 is on the rear side opposite to the pressure receiving side of the variable damping force disk valve 61. Form a defined back pressure chamber 77. Then, the assist ring 76
An assist spring 78 for urging the assist ring 76 in the direction of applying a predetermined light set load in the direction of the damping force variable disc valve 61 is mounted between the outer opening end face of the mold member 71 and the mold material 71.

On the side wall of the small diameter portion of the stator 58 and on the surface of the coil case 59 where the back pressure chamber 77 is formed, there is formed a pilot pressure introduction passage 79 communicating between the inside of the pilot pressure chamber 65 and the back pressure chamber 77. I have. In the figure, 8
0 denotes a fixed seal member, and 50 denotes a grommet.

The pressure stroke side damping force variable mechanism 33
Has the same structure as that of the variable extension stroke side damping force mechanism 31, the same components are denoted by the same reference numerals, and description thereof is omitted.

Since the shock absorber SA is configured as described above, the flow path through which the fluid can flow during the expansion stroke includes opening the expansion disk valve 22a from the upper chamber 21a through the expansion communication hole 22b. The expansion-side main flow path (see FIG. 5) which flows into the lower chamber 21b by valve, the upper communication hole 21c, the upper annular flow path 28a, the expansion-side communication flow path 31a, the reservoir chamber 23a, and the check flow path 24a from the upper chamber 21a. And a flow path through which the fluid can flow at the time of the pressure stroke. The flow path through which the fluid can flow during the pressure stroke passes through the pressure-side communication hole 22d from the lower chamber 21b. The compression-side main flow path (see FIG. 3) that opens the compression-side disk valve 22c and flows into the upper chamber 21a, the lower communication groove 24b, the lower annular flow path 29a, and the compression-side communication flow path 3 from the lower chamber 21b.
3a, the reservoir chamber 23a, the check channel 34, the upper annular channel 28a, and the upper chamber 21a via the upper communication hole 21c.
There are two flow paths, a pressure side bypass flow path that flows into the flow path.

Therefore, the damping force characteristic on the extension stroke side becomes a hard characteristic when the extension side bypass flow path is closed, and becomes a soft characteristic when the extension side bypass flow path is opened. The characteristic can be variably controlled to an arbitrary characteristic between the characteristic and the soft characteristic.

On the other hand, the damping force characteristic on the compression stroke side becomes a hard characteristic when the compression-side bypass flow path is closed, and becomes a soft characteristic when the compression-side bypass flow path is opened. Any characteristic can be variably controlled between the soft characteristic and the soft characteristic.

The cross-sectional area of the expansion side bypass flow path is variably controlled to an arbitrary flow path cross-sectional area by variably controlling a drive signal for the solenoid coil 68 of the expansion stroke side damping force variable mechanism 31. Can be. The cross-sectional area of the pressure-side bypass flow path can be variably controlled to an arbitrary flow-path cross-sectional area by variably controlling a drive signal for the solenoid coil 68 of the pressure-stroke-side damping force variable mechanism 33.

That is, in the state where the power supply to the solenoid coil 68 is released (no power supply), the pilot pressure chamber 65
Through the small hole 66a of the pilot bush 66,
The pressurized hydraulic pressure in one chamber of the cylinder 21 defined by the piston 22 is supplied, and the inside of the recess 72 a on the back pressure chamber side of the pilot valve 73 is communicated via a return flow path 75 and the like. Due to the same pressure as the fluid pressure in the reservoir chamber 23a, the inner peripheral movable portion 73b of the pilot valve 73 is pushed away from the valve seat 58a by the differential pressure to open the valve. Hydraulic fluid flows out, the hydraulic pressure in the pilot pressure chamber 65 and the back pressure chamber 77 increases in the reservoir chamber 2
The pressure drops to the same pressure as the liquid pressure in 3a. Accordingly, the variable damping force disc valve 61 easily opens against the light set load of the assist spring 78, and almost the entire flow rate of the hydraulic fluid flows through the bypass flow path side and the piston 22 side and the base 2
Since the flow does not flow on the fourth side, the generated damping force at this time has a soft characteristic determined by the damping force variable disc valve 61.

On the other hand, when the solenoid coil 68 is energized, as shown by the arrow in FIG.
Solenoid coil 68, coil case 59, cover 7
2. A magnetic path is formed around the magnetic flux reinforcing plate 74, the pilot valve 73, and the stator 58, and the pilot valve 73 is attracted to the valve seat 58a.
Is maintained in a closed state, whereby the pressure in the pilot pressure chamber 65 is maintained.

Therefore, the pressure receiving side of the variable damping force disk valve 61 and the back pressure chamber 77 into which the pressure in the pilot pressure chamber 65 is introduced have the same pressure, so that the assist spring 78 is provided.
The variable load damping force disc valve 61 is maintained in the closed state by the set load, and the bypass flow path is completely closed, so that almost all the flow rate of the hydraulic fluid flows through the piston 22 side, and the expansion side disc valve 22a Alternatively, since the compression-side disc valve 22c is opened for circulation, the generated damping force at this time has a hard characteristic determined by the expansion-side disc valve 22a or the compression-side disc valve 22c.

As shown in FIG. 8, ON-OFF of the current supplied to the solenoid coil 68 is repeatedly given at a predetermined high frequency cycle Ts by PWM (pulse width modulation) control. The ratio of the ON state time, that is, the on-duty ratio (ON
By variably controlling (Duty) between 0% and 100%, as shown in FIG. 9, between the soft characteristic (0%) and the hard characteristic (100%) according to the ratio (%) The damping force characteristics can be variably controlled.

The on-duty ratio is variably controlled in accordance with a control signal V obtained from the vehicle behavior (sprung vertical acceleration G signal) as described later.

As described above, since the opening and closing of the pilot valve 73 is repeated at a high frequency cycle, durability of the pilot valve 73 due to abrasion of the abutting portion of the valve seat 58a is a problem. In the configuration, the valve seat 58a
The pilot valve 73 itself, which is in contact with, is made of a single thin plate made of hard spring steel to eliminate the problem of durability due to wear.

On the other hand, the spring steel constituting the pilot valve 73 has a high carbon content and a low maximum saturation magnetic flux density.
Attraction of the solenoid coil 68 to the valve seat 58a when the solenoid coil 68 is energized causes a problem that the maximum damping force set value is reduced. However, in the embodiment of the present invention, the iron material having a low carbon content ( By providing a magnetic flux reinforcing plate 74 made of a ferromagnetic material in a state where the magnetic flux reinforcing plate 74 is stacked on the inner peripheral movable portion 73b of the pilot valve 73 so as to float, the valve seat 58 when the solenoid coil 68 is energized is provided.
The attraction force of the pilot valve 73 with respect to a is increased, whereby the maximum damping force set value can be increased, and the degree of freedom in damping force tuning can be increased.

Next, in the control operation of the control unit 4, a control signal V used for controlling the damping force characteristic of each shock absorber SA is obtained from each sprung vertical acceleration G signal detected by each vertical G sensor 1. The configuration of the signal processing circuit for this will be described based on the block diagram of FIG.

First, in B1, a phase delay compensation formula is used,
Each vertical G sensors _{1 (1 FL, 1 FR,} 1 RL, 1 RR) on each spring is detected by the vertical acceleration _{G (G FL, G FR,} G RL, G RR)
Is converted into a sprung vertical speed signal at each tower position. The general expression of the phase delay compensation can be expressed by the following transfer function expression (1).

G _(S) = (AS + 1) / (BS + 1) (1) (A <B) Then, a frequency band (0.5 Hz to 3) required for damping force characteristic control.
Hz), has the same phase and gain characteristics as the case of integration (1 / S), and as a phase lag compensation equation for lowering the gain on the low frequency side (up to 0.05 Hz), the following transfer function equation (2 ) Is used.

G _(S) = [(0.001 S + 1) / (10S + 1)] × γ (2) Here, γ is a signal when the speed is converted by integration (1 / S). This is a gain for matching the gain characteristics, and is set to γ = 10 in the embodiment of the present invention. As a result, as shown in the gain characteristic of the solid line in FIG. 11A and the phase characteristic of the solid line in FIG. 11B, the frequency band (0.5 Hz to 3 Hz) required for damping force characteristic control is obtained.
2), only the gain on the low frequency side is reduced without deteriorating the phase characteristics. Note that FIG.
Dotted lines (a) and (b) show the gain characteristic and phase characteristic of the sprung vertical velocity signal that has been velocity-converted by integration (1 / S).

In B2, a band-pass filter process for cutting off components other than the target frequency band to be controlled is performed. That is, the band-pass filter BPF is composed of a second-order high-pass filter HPF (0.3 Hz) and a second-order low-pass filter LPF (4 Hz), and has a sprung vertical velocity that targets a sprung resonance frequency band of the vehicle. Δx (Δx _FL ,
Δx _FR , Δx _RL , Δx _RR ) signals are obtained.

On the other hand, in B3, as shown in the following equation (3),
Using the transfer function Gu _(S) from each sprung vertical acceleration to the sprung-unsprung relative velocity, the vertical acceleration G (G _FL , G _FR , G _RL , G _{RR )} detected by each vertical G sensor 1. ) Signal from the sprung-unsprung relative velocity (Δx
−Δx ₀ ) [(Δx−Δx ₀ ) _FL , (Δx−Δx
₀ ) _FR , (Δx−Δx ₀ ) _RL , (Δx−Δx ₀ ) _RR ] signal is obtained. Gu _(S) = − ms / (cs + k) (3) where m is a sprung mass, c is a damping coefficient of the suspension, and k is a spring constant of the suspension.

In B4 following B2 and B3, the following equation
Based on (4), the control signal V used for the special control of the damping force of each shock absorber SA is obtained. V = α · Δx · Ku (4) where α is a constant, and Ku is a control for the relative speed between the sprung and unsprung shown in FIG. Based on the gain variable characteristic map, the control gain is variably set to a value inversely proportional to the sprung-unsprung relative speed (Δx−Δx ₀ ).

Next, the operation of the damping force characteristic control of the shock absorber SA in the control unit 4 will be described with reference to the flowchart of FIG. In addition,
This control is performed for each shock absorber SA _FL , SA _FR , SA
_This is performed for each of _RL and SA _RR .

At step 101, the sprung vertical speed Δx
It is determined whether or not the control signal V based on
If ES (V> 0), the process proceeds to step 102 in order to variably control only the damping force characteristic on the extension stroke side to the hard characteristic, and the solenoid of the extension stroke side damping force variable mechanism 31 in each shock absorber SA is driven. The on-duty ratio (%) of the drive current is variably set based on the control signal-on-duty ratio compensation map shown in FIG.

If NO (V ≦ 0), step 1
Go to 03. In step 103, it is determined whether or not the control signal V is a negative value. If YES (V <0), step 104 is performed to variably control only the damping force characteristic on the pressure stroke side to the hard characteristic. The on-duty ratio (%) of the drive current for driving the solenoid of the pressure stroke side damping force variable mechanism 33 in each shock absorber SA is variably set based on the control signal-on duty ratio compensation map shown in FIG. . In this case, since the control signal V is a negative value, an absolute value is used.

If NO (V = 0), the process proceeds to step 105 to fix the damping force characteristics of both the extension stroke and the compression stroke to the soft characteristics, and the extension stroke side damping force variable mechanism 3 is set.
Both the on-duty ratio (%) of the drive current for driving the solenoid 1 and the on-duty ratio (%) of the drive power supply for driving the solenoid of the pressure-stroke-side damping force variable mechanism 33 are 0.
Set to%.

The compensation map shown in FIG. 14 is for compensating for the nonlinearity of the generated damping force characteristics with respect to the on-duty ratio (%). That is, since the generated damping force characteristic with respect to the on-duty ratio (%) of the driving power supply for the solenoid coil 68 does not become a linear characteristic as shown by the solid line in FIG. 15, the on-duty ratio (%) is proportional to the value of the control signal V. %), The damping force of the shock absorber SA is generated non-linearly with respect to the control signal V, so that damping force characteristic control suitable for vehicle behavior (control signal V) cannot be performed (FIG. 16). Dotted line).

Therefore, in the embodiment of the present invention, the non-linearity of the generated damping force characteristic with respect to the on-duty ratio (%) is corrected using a non-linearity compensation map of the on-duty ratio (%) variable characteristic with respect to the control signal V. Thus, the linearity of the damping force variable characteristic with respect to the control signal V can be ensured (see the solid line in FIG. 16).

Next, the operation of the damping force characteristic control will be described with reference to the time chart of FIG. When the control signal V based on the sprung vertical speed Δx changes as shown in FIG.
As shown in the figure, when the value of the control signal V is 0, the damping force characteristics of the extension stroke and the pressure stroke of the shock absorber SA are both fixedly controlled to soft characteristics (SS). Also, when the value of the control signal V becomes a positive value, the extension stroke side is variably controlled to the hard characteristic according to the value of the control signal V, while the pressure stroke side is fixedly controlled to the soft characteristic (HS).

When the value of the control signal V becomes a negative value,
The compression stroke side is variably controlled to a hard characteristic according to the value of the control signal V, while the extension stroke side is fixedly controlled to a soft characteristic (S
H).

Next, among the damping force characteristic control operations of the control unit 4, mainly a switching operation state of the control region of the shock absorber SA will be described with reference to a time chart of FIG.

In the time chart of FIG.
Is a state in which the control signal V based on the sprung vertical speed Δx is reversed from a negative value (downward) to a positive value (upward). At this time, the relative speed (Δx−Δx ₀ ) is still a negative value ( Since the stroke of the shock absorber SA is the pressure stroke side), at this time, the shock absorber SA is determined based on the direction of the control signal V (the sprung vertical speed Δx).
Has a hard characteristic on the extension stroke side and a soft characteristic on the pressure stroke side.

In the area b, the control signal V remains positive (upward), and the relative speed (Δx−Δx ₀ ) changes from a negative value to a positive value (the stroke of the shock absorber SA is on the extension stroke side).
At this time, the control signal V
Based on the direction of (sprung vertical velocity Δx), the shock absorber SA has a hard characteristic on the extension stroke side and a soft characteristic on the compression stroke side, and the stroke of the shock absorber is also the extension stroke. The extension stroke, which is the stroke of the shock absorber SA at that time, is controlled by the control signal V
Is obtained according to the value of.

Area c is a state where the control signal V is reversed from a positive value (upward) to a negative value (downward).
At this time, since the relative speed (Δx−Δx ₀ ) is still in a region where the value is a positive value (the stroke of the shock absorber SA is on the extension stroke side), the control signal V (the sprung vertical speed Δx) The shock absorber SA is controlled to have a hard characteristic on the pressure stroke side and a soft characteristic on the extension stroke side based on the direction of the shock absorber SA. Therefore, in this region, the extension stroke side, which is the stroke of the shock absorber SA at that time, has the soft characteristic.

In the area d, the control signal V remains negative (downward), and the relative speed (Δx−Δx ₀ ) changes from a positive value to a negative value (the stroke of the shock absorber SA is on the extension stroke side).
At this time, the shock absorber S is determined based on the direction of the control signal V (the sprung vertical speed Δx).
A is such that the pressure stroke side is hard and the extension stroke side is controlled with soft characteristics, and the stroke of the shock absorber is also the pressure stroke. Therefore, in this region, the pressure stroke side, which is the stroke of the shock absorber SA at that time, is controlled. The hardware characteristic becomes proportional to the value of the signal V.

As described above, in the embodiment of the present invention, when the control signal V based on the sprung vertical speed Δx and the relative speed (Δx−Δx ₀ ) have the same sign (region b, region d).
According to the skyhook theory, the stroke side of the shock absorber SA at that time is controlled to a hard characteristic, and when the sign is different (regions a and c), the stroke side of the shock absorber SA at that time is controlled to a soft characteristic. The same control as the damping force characteristic control based on this is performed. Further, in the embodiment of the present invention, when the stroke of the shock absorber SA is switched, that is, when shifting from the region a to the region b and from the region c to the region d (from the soft characteristic to the hard characteristic), the switching is performed. Since the position of the damping force characteristic on the switching side has already been switched to the hardware characteristic in the previous areas a and c, the switching from the soft characteristic to the hardware characteristic is performed without time delay.

As described in detail above, the vehicle suspension system according to the embodiment of the present invention has the following effects. The control is performed by correcting the non-linearity of the generated damping force characteristic with respect to the on-duty ratio (%) of the drive current for the solenoid coil 68 using a non-linearity compensation map of the on-duty ratio (%) variable characteristic with respect to the control signal V. The linearity of the damping force variable characteristic with respect to the signal V can be ensured, thereby making it possible to enhance the control effect.

Also, by stacking the magnetic flux reinforcing plates 74 without lowering the attraction when the solenoid coil 68 is energized, and by forming the pilot valve 73 from one thin plate made of hard spring steel, The effect that the durability of the valve 73 can be improved is obtained.

In general, since a large amount of magnetic flux flows near the surface of a magnetic body, a thin plate having the same cross-sectional area has a larger total amount of magnetic flux than an integrated one. As in the embodiment of the present invention, by using a predetermined number of magnetic flux reinforcing plays 74 of a predetermined thickness in a stacked manner, the weight of the inner peripheral movable portion 74b of the pilot valve 74 can be reduced, and as a result, the damping force variable mechanism 31 The responsiveness of the suspension system can be improved, and the responsiveness of the suspension system can be improved.

Although the embodiments of the present invention have been described above, the specific configuration is not limited to the embodiments of the present invention, and even if there is a design change or the like without departing from the gist of the present invention. Included in the present invention.

For example, in the embodiment of the present invention, only one magnetic flux reinforcing plate is formed, but a plurality of magnetic flux reinforcing plates can be used in a stacked state.

In the embodiment of the present invention, the notch for forming the working fluid passage is formed on the outer periphery of the magnetic flux reinforcing plate, but a plurality of protrusions may be formed on the outer periphery. One or a plurality of through holes may be formed in whole or in part.

In the embodiment of the present invention, the pilot valve has a fixed outer circumference, but the positional relationship between the fixed part and the movable part can be set arbitrarily.

[0068]

As described above, the first aspect of the present invention is as follows.
The electromagnetic valve control device described above is configured to nonlinearly change the on-duty ratio of the drive current with respect to the opening control signal, so that the opening control of an arbitrary characteristic can be performed for a predetermined control signal. The effect of being able to do so is obtained.

Further, in the electromagnetic valve control device for controlling the damping force characteristic of the shock absorber according to the second aspect, the on-duty ratio of the drive current with respect to the damping force characteristic control signal is nonlinearly changed. An effect is obtained in that damping force characteristic control of arbitrary characteristics can be performed on the damping force characteristic control signal.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing a vehicle suspension device to which a solenoid valve control device for varying a damping force characteristic of a shock absorber according to an embodiment of the present invention is applied.

FIG. 2 is a system block diagram showing a vehicle suspension device to which the electromagnetic valve control device for varying the damping force characteristic of the shock absorber according to the embodiment of the present invention is applied.

FIG. 3 is a sectional view showing a shock absorber.

FIG. 4 is an enlarged sectional view showing a damping force variable mechanism part of the shock absorber.

FIG. 5 is an enlarged sectional view showing a piston portion of the shock absorber.

FIG. 6 is an enlarged perspective view showing a pilot valve and a magnetic flux reinforcing plate in the damping force variable mechanism.

FIG. 7 is an explanatory diagram showing a magnetic path in the damping force variable mechanism.

FIG. 8 is a time chart showing a PM control state for a solenoid coil in the damping force variable mechanism.

FIG. 9 is a diagram illustrating a damping force variable characteristic with respect to a piston speed in a damping force variable mechanism.

FIG. 10 is a block diagram showing a signal processing circuit for obtaining a control signal from a sprung vertical acceleration in the vehicle suspension system.

FIG. 11 is a diagram showing a gain characteristic (a) and a phase characteristic (b) of a sprung vertical velocity signal converted by using a phase lag compensation equation.

FIG. 12 is a control gain variable characteristic map with respect to a sprung-unsprung relative speed in the vehicle suspension system.

FIG. 13 is a flowchart showing a damping force characteristic control operation of a control unit in the vehicle suspension system.

FIG. 14 is a control signal-on duty ratio compensation map in the vehicle suspension system.

FIG. 15 is a characteristic diagram of a generated damping force with respect to an on-duty ratio of a drive current in a vehicle suspension device.

FIG. 16 is a time chart showing a damping force characteristic variable state with respect to a control signal in the vehicle suspension system.

FIG. 17 is a time chart showing a damping force characteristic control operation of a control unit in the vehicle suspension system.

[Explanation of symbols]

 SA Shock absorber 31 Variable stroke side damping force variable mechanism (solenoid valve) 33 Variable compression stroke side damping force variable mechanism (solenoid valve)

[Procedure amendment]

[Submission date] August 21, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0002

[Correction method] Change

[Correction contents]

[0002]

2. Description of the Related Art Conventionally, as an electromagnetic valve control device driven by a solenoid, for example, a device described in Japanese Patent Application Laid-Open No. 3-153412, "Suspension control method for continuously changing damping force characteristics" is known. ing.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0003

[Correction method] Change

[Correction contents]

In this conventional example, a solenoid valve control device driven by a solenoid is used as means for switching and controlling the damping force characteristic of a shock absorber. The damping is performed by variably controlling the opening area of a hydraulic fluid flow path. For a normally open solenoid valve that switches force characteristics, the drive current PWM
The control is performed and a high damping force state (on duty ratio 100
%) And a low damping force state (on duty ratio 0%) at a high speed, and a ratio (on duty ratio) of a time period of a high damping force state (energization on) and a time of a low damping force state (energization off). ) Is adjusted to form an intermediate damping force state.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

[0004]

However, in the solenoid valve control device driven by a solenoid described in the conventional example, the on-duty ratio is variably set in a proportional (linear) manner with respect to a vehicle body oscillation value (control signal). Therefore, there were problems as described below. That is, in general, in a solenoid valve of the type in which the opening area (fluid flow rate) of the fluid flow passage is variably controlled by PWM controlling the drive current to the solenoid, when the on-duty ratio of the drive current is 0%, When the opening area is fully open (flow rate 0%) and the on-duty ratio is 100%, it is fully closed (flow rate 100%)
However, in other intermediate bands, an intermediate opening area (intermediate flow rate) is to be obtained by switching the energized ON state and the OFF state at a high speed. If the ON time ratio is 50%, the average opening area within a unit time should be 50% of the fully open state (50% flow rate). However, even if the valve is opened, a predetermined delay (time lag) occurs from the state in which the flow is stopped until the fluid actually starts flowing, and the responsiveness is deteriorated because the valve is repeatedly opened and closed at a high speed. For this reason, the calculated value (flow rate 50%) is lower than that. Accordingly, since the fluid flow rate is non-linearly generated with respect to the on-duty ratio of the drive current to the solenoid, if the on-duty ratio is variably set proportionally (linearly) with respect to the control signal (vehicle fluctuation value), the fluid flow rate ( The damping force also changes nonlinearly.

Claims (2)

[Claims] An electromagnetic valve control device configured to control the opening degree of an electromagnetic valve by variably controlling the on-duty ratio of the driving current to the electromagnetic valve by PWM control. An electromagnetic valve control device wherein an on-duty ratio is changed non-linearly. 2. A shock absorber configured to variably control an on-duty ratio of a drive current to a damping force characteristic variable control solenoid valve by PWM control to control an opening of the damping force characteristic variable control solenoid valve. A solenoid valve control for damping force characteristic control of a shock absorber, characterized in that an on-duty ratio of a drive current to a damping force characteristic control signal is changed in a non-linear manner. apparatus.