JP2007083853A - Suspension system for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suspension system for a vehicle capable of supplementing shortage of a rolling restraining effect in slalom travelling of a stabilizer device. <P>SOLUTION: This suspension system 10 furnished with the stabilizer device 22 is provided with an electronic control unit ECU 200 and a shock absorber 34 capable of controlling damping force. It practices a rolling restraining program by the ECU 200 and increases damping force of the shock absorber 34 when it detects that operation to change over the revolving direction is carried out. Consequently, it is possible to supplement the shortage of the rolling restraining effect and to properly restrain rolling even when delayed return of torsion of the stabilizer 70 is caused by working resistance of an actuator 80 of the stabilizer device 22. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a suspension system including an active stabilizer device in which an effect of suppressing a roll of a vehicle body is made variable.

In recent years, active stabilizer devices in which the roll suppression effect, which is the effect of suppressing the roll of the vehicle body, is made variable by changing the twist amount of the stabilizer bar per roll amount of the vehicle body, have been studied. Patent Document 1 below describes a stabilizer device in which a stabilizer bar includes a pair of left and right bar members, and the pair of bar members are rotated relative to each other by an actuator to change the roll suppression effect. .
Special table 2002-518245 gazette

  The stabilizer system of the said patent document 1 can be controlled based on the lateral acceleration of a vehicle body, for example. Specifically, for example, when the lateral acceleration is large, the amount of twist of the stabilizer bar per roll amount of the vehicle body is increased in order to enhance the roll suppression effect, and the roll is appropriately suppressed. However, when performing slalom traveling, for example, the stabilizer bar is twisted by the actuator when it rolls to one of the left and right, and then the twist of the stabilizer bar is eliminated before the roll to the other of the left and right starts. Although desirable, there is a case where the twist of the stabilizer bar does not quickly return due to the operating resistance of the actuator. Roll suppression effect of the active stabilizer device (hereinafter sometimes abbreviated as “stabilizer device”) after the roll direction is switched from one of the left and right to the other in the above example due to delay in the return of the twist of the stabilizer bar There is a problem that the roll of the vehicle body may not be properly suppressed.

  Taking the above problems as an example, there are various problems that can be an obstacle to improving the practicality of the suspension system, such as demonstrating an appropriate roll suppression effect by a suspension system equipped with a stabilizer device that has been studied conventionally. is there. That is, there is room for improvement from various viewpoints in the suspension system provided with the stabilizer device which has been studied conventionally, and it is possible to improve the practicality of the suspension system by improving the suspension system. The present invention has been made in view of such circumstances, and an object of the present invention is to obtain a more practical vehicle suspension system.

  In order to solve the above-described problems, a vehicle suspension system according to the present invention includes (a) a pair of damping force generation mechanisms capable of changing the magnitude of damping force, and (b) left and right wheels. A stabilizer bar configured to include a stabilizer bar connected to each of the actuators and an actuator that changes the twisting amount of the stabilizer bar per roll amount of the vehicle body to change the roll suppression effect of the vehicle body, and crosses the neutral position. When the steering operation is performed, at least one damping force of the pair of damping force generation mechanisms is increased more than before the steering operation is performed.

  According to the vehicle suspension system of the present invention, for example, when a steering operation from one side to the other side, that is, an operation crossing the neutral position is performed during slalom traveling, for example, roll suppression of the stabilizer device is performed. In order to compensate for the lack of effect, the roll after crossing the neutral position can be appropriately suppressed by increasing the damping force of at least one of the pair of damping force generation mechanisms. That is, the suspension system of the present invention can exhibit an appropriate roll suppressing effect even during slalom running, for example, and is a more practical suspension system. Various aspects of the vehicle suspension system of the present invention and their functions and effects will be described in detail in the following [Aspect of the Invention] section.

Aspects of the Invention

  In the following, some aspects of the invention that can be claimed in the present application (hereinafter sometimes referred to as “claimable invention”) will be exemplified and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is for the purpose of facilitating the understanding of the claimable invention, and is not intended to limit the combinations of the constituent elements constituting the claimable invention to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which some constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention.

  In the following paragraphs, (1) is combined with claim 1, (3) is combined with claim 2, (4) is combined with claim 3, and (8) and (9) are combined. These correspond to claim 4 respectively.

(1) A pair of damping force generation mechanisms provided corresponding to the left and right wheels and capable of changing the magnitude of the damping force with respect to the approach and separation between each of the left and right wheels and the vehicle body; ,
The stabilizer bar connected to each of the left and right wheels, and the amount of twist of the stabilizer bar per roll amount of the vehicle body according to the roll moment estimated physical amount, which is a physical amount capable of estimating the magnitude of the roll moment applied to the vehicle body A suspension system comprising a stabilizer device including an actuator that changes the roll suppression effect of the vehicle body by the stabilizer bar by changing
A vehicle suspension system configured to increase a damping force of at least one of the pair of damping force generation mechanisms when a steering operation is performed across a neutral position.

  The stabilizer device described in this section is a so-called active stabilizer device, and by changing the amount of twist of the stabilizer bar per roll amount of the vehicle body, that is, the force for suppressing the roll caused by the elastic force of the stabilizer bar. By changing the above, it is possible to exert an appropriate roll suppression effect (for example, it can be expressed as “degree of roll suppression”). That is, when the roll amount is the same, the roll suppression effect can be increased or decreased by increasing or decreasing the amount of twist of the stabilizer bar. Specifically, for example, if the twist amount is relatively large with a relatively small roll amount, the roll suppression effect is increased, and the roll amount during turning can be reduced.

  However, the amount of twisting of the stabilizer bar becomes inappropriate, and an appropriate roll suppressing effect may not be exhibited. Specifically, for example, during a slalom run, an S-curve run, etc., a steering operation from one side to the other, that is, an operation crossing a neutral position (for example, an operation position for moving the vehicle straight) is performed. This is the case. When an operation that crosses the neutral position is performed, in other words, when a turning direction switching operation that switches the turning direction of the vehicle is performed, the vehicle body that rolls to either the left or right side rolls to the other side. To do. In such a state, after the stabilizer bar is twisted when the vehicle body rolls to either the left or right side, the roll amount of the vehicle body decreases and the twist of the stabilizer bar decreases until the vehicle body rolls to the other side of the left and right. Although it is desirable that the twist of the stabilizer bar is eliminated, there may be a case where the return of the twist of the stabilizer bar may be delayed due to, for example, the operating resistance of the actuator. If there is a delay in the return of the twisting of the stabilizer bar, the roll restraining effect of the stabilizer device becomes insufficient when the roll to the other side (that is, the roll after crossing the neutral position), and the roll to the other side It may not be properly controlled.

  Therefore, according to the suspension system described in this section, when a steering operation is performed across the neutral position, for example, a pair of damping forces is generated in order to compensate for the lack of the roll suppression effect of the stabilizer device as described above. By increasing the damping force of at least one of the mechanisms more than before the steering operation is performed, the roll to the other can be appropriately suppressed. That is, the suspension system described in this section can exhibit an appropriate roll suppressing effect even during slalom traveling, for example, and is a more practical suspension system. Further, according to the suspension system described in this section, for example, even if the vehicle is not provided with a stroke sensor, a roll sensor, or the like, it is possible to detect a state where the roll suppression effect is insufficient based on a steering operation or the like. The suspension system is more practical in terms of cost.

  In the suspension system described in this section, in order to appropriately suppress the roll, the torsion amount of the stabilizer bar is set to the torsion amount according to the estimated roll moment physical quantity by the actuator. The roll moment estimated physical quantity can be a physical quantity capable of estimating the magnitude of the external force roll moment that is a roll moment acting on the vehicle body by an external force such as a centrifugal force during turning, for example, the roll acceleration, lateral It can be acceleration or a physical quantity that can be estimated. The lateral acceleration can be estimated based on, for example, a steering angle, a yaw rate, a vehicle speed, and the like.

  The structure of the damping force generation mechanism described in this section is not particularly limited as long as the magnitude of the damping force can be changed. For example, a shock absorber that uses the viscous resistance force of oil or an electromagnetic that uses electromagnetic force. A type shock absorber or the like can be included. Further, the damping force generation mechanism described in this section can change the damping coefficient, for example, in order to change the magnitude of the damping force.

(2) The suspension system is
The vehicle suspension system according to item (1), configured to increase the damping force of at least one of the pair of damping force generation mechanisms in response to an insufficient roll suppression effect of the stabilizer device.

  According to the aspect described in this section, for example, the amount of increase in the damping force can be increased as the insufficient amount of the roll suppression effect increases (for example, as the return delay of twisting of the stabilizer bar increases), and more appropriately. Roll can be suppressed. Further, according to the aspect described in this section, for example, when the insufficient amount of the roll suppression effect is equal to or less than the set value, the damping force can be prevented from increasing.

(3) The suspension system is
It is configured to increase the damping force of at least one of the pair of damping force generating mechanisms according to the degree of return delay of twisting of the stabilizer bar when a steering operation is performed across the neutral position (1) The suspension system for a vehicle according to item or (2).

  In the suspension system described in this section, the operation amount of the actuator and the increase / decrease amount of the twist of the stabilizer bar are closely related. Therefore, when the suspension system described in this section includes, for example, a sensor that detects the operation amount of the actuator, the degree of return delay of the stabilizer bar torsion is acquired based on the operation amount of the actuator. Can do. Then, for example, an insufficient amount of roll suppression effect can be acquired based on the degree of return delay of the twist of the stabilizer bar. Further, in the suspension system described in this section, the degree of return delay of the twist of the stabilizer bar correlates with, for example, the operation speed, the vehicle speed, the estimated physical moment of the roll moment, etc., and the stabilizer bar is based on at least one of them. The degree of return delay can be estimated, or at least one damping force of the damping force generation mechanism can be increased.

(4) The suspension system is
4. The vehicle suspension system according to any one of items (1) to (3), configured to increase at least one damping force of the pair of damping force generation mechanisms according to an operation speed.

  It is considered that there is a correlation between the operation speed of the steering operation crossing the neutral position and the degree of delay in returning the twist of the stabilizer bar, that is, the insufficient amount of the roll suppression effect. Specifically, when the operation speed is low, the return delay of the stabilizer bar twist tends to decrease, and the amount of insufficient roll suppression effect tends to decrease. On the other hand, when the operation speed is high, the roll suppression effect increases. The shortage tends to increase. Therefore, according to the aspect described in this section, for example, the increase amount of the damping force can be determined based on the operation speed of the steering operation crossing the neutral position, and the roll can be more appropriately suppressed. Further, according to the aspect described in this section, for example, when the operation speed of the steering operation crossing the neutral position is equal to or lower than the set speed, the damping force can be prevented from increasing. In the aspect described in this section, the operation speed of the steering operation crossing the neutral position is, for example, the average operation speed of the steering operation (switching operation that is an operation approaching the neutral position) until the neutral position is crossed. It can be acquired based on the operation speed at the time of crossing the neutral position. Note that the mode described in this section is an example of a mode in which the damping force of the damping force generation mechanism is increased according to the degree of delay in return of twisting of the stabilizer bar.

(5) The suspension system is
5. The vehicle suspension system according to any one of (1) to (4), configured to increase at least one damping force of the pair of damping force generation mechanisms according to a vehicle speed.

  When the vehicle speed is high, the roll moment during turning is larger than when the vehicle speed is low, and thus the roll suppression effect is often relatively large. For this reason, the amount of twist of the stabilizer bar is relatively large, and the return delay amount of the amount of twist tends to increase. In the aspect described in this section, the vehicle speed is, for example, the average of the vehicle speed or the neutral position during the steering operation (switching operation that is an operation in a direction approaching the neutral position) until the neutral position is crossed. It can be acquired based on the vehicle speed at the time of crossing. Note that the mode described in this section is an example of a mode in which the damping force of the damping force generation mechanism is increased according to the degree of delay in return of twisting of the stabilizer bar.

(6) The suspension system is
The vehicle according to any one of (1) to (5), wherein the vehicle is configured to increase at least one damping force of the pair of damping force generation mechanisms in accordance with a roll moment estimated physical quantity at the time of switching back operation. Suspension system.

  For example, in a turning state in which the operation amount from the neutral position is large, the turning radius is small, the turning speed is high, etc., the roll moment is relatively large and the twist amount of the stabilizer bar is relatively large. The degree of return delay tends to increase. Therefore, the roll can be appropriately suppressed by increasing the damping force according to the roll moment estimated physical quantity. The switch-back operation is simply an operation in a direction approaching the neutral position. The roll moment estimated physical quantity at the time of the switchback operation, which is the time when the switchback operation is performed, is reversed, for example, from the time when the switchback operation is started (for example, the operation direction is changed from the direction away from the neutral position to the approaching direction). Time), or a time when a return operation that tends to cause a twisting return delay of the stabilizer bar is performed (for example, when an operation speed in a direction approaching the neutral position exceeds a set value). Note that the mode described in this section is an example of a mode in which the damping force of the damping force generation mechanism is increased according to the degree of delay in return of twisting of the stabilizer bar.

  (7) The suspension system increases the damping force of the turning outer wheel side of the pair of damping force generating mechanisms when the steering operation is performed across the neutral position. 6. The vehicle suspension system according to any one of items 6).

  When the increase amount of the damping force is relatively small, it is convenient to increase the damping force on the turning outer wheel side in order to suppress the lowering of the vehicle body on the turning outer wheel side. It is desirable to increase the damping force of only the turning outer wheel side of the pair of damping force generation mechanisms.

(8) The stabilizer bar is
Each has a shaft-like torsion bar portion rotatably held on the vehicle body and an arm portion extending from one end portion of the torsion bar portion in a direction crossing the rotation axis, and a starting end portion of the torsion bar portion And including a pair of left and right bar members connected to the actuator,
Each of the pair of bar members is configured so that the amount of twist of the stabilizer bar per roll amount is changed by changing the relative rotation amount of the starting portion of each of the pair of bar members. The vehicle suspension system according to any one of the above.

  The aspect described in this section is an aspect in which the stabilizer bar is configured to include two bar members. When the relative rotation amount of the starting end portions of these two bar members is changed by the actuator, the twist amount per roll amount is changed, and the roll suppression effect is changed. In such an aspect, when the relative rotation amount of the two bar members returns to 0, a return delay is likely to occur due to the operating resistance of the actuator, and thus the damping force is increased when a steering operation is performed across the neutral position. The effect is particularly great.

(9) The actuator is
The vehicle suspension system according to item (8), including an electromagnetic motor serving as a driving force source and a speed reducer that decelerates and outputs the driving rotation of the electromagnetic motor input to the motor.

The mode described in this section is a mode in which the actuator includes a speed reducer. Although it is desirable to reduce the motor load by adopting a reduction gear having a large reduction ratio, the operating resistance of the reduction gear itself becomes relatively large. For this reason, the aspect described in this section has a great effect of increasing the damping force when a steering operation crossing the neutral position is easily performed because the return delay of the twisting of the stabilizer bar is likely to be large. The reduction gear may be a gear having a large reduction ratio, such as a harmonic gear mechanism (sometimes called “harmonic drive (registered trademark)”).

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is by no means limited to the following examples, and in addition to the following examples, there are various types based on the knowledge of those skilled in the art including the aspects described in the above [Aspect of the Invention] section. It can implement in the various aspect which gave the change and improvement of these.

1. Vehicle suspension system.
FIG. 1 schematically shows a vehicle suspension system 10 (hereinafter simply abbreviated as “suspension system”) according to an embodiment of the present invention. This suspension system 10 is provided corresponding to each wheel 16 and is provided on each of the independent suspension type suspension device 20 that connects each wheel 16 and the vehicle body so as to be close to and away from each other, and each of the front wheel side and the rear wheel side of the vehicle. And two active stabilizer devices 22 (hereinafter, may be abbreviated as “stabilizer device 22”) that are provided and suppress the roll of the vehicle body. In this embodiment, four suspension devices 20 are provided, but two suspension devices 20 are shown in the figure.

2. Suspension device.
FIG. 2 schematically shows a part of the suspension device 20 and a portion of the one stabilizer device 22 from the center in the vehicle width direction in front of the vehicle to the wheel 16 on one side. The suspension device 20 is of a generally well-known double wishbone type, and includes an upper arm 30 as a wheel support member having one end rotatably connected to the vehicle body and the other end connected to the wheel 16. A lower arm 32 is provided. The upper arm 30 and the lower arm 32 are rotated around the one end (vehicle side) in accordance with the approach and separation (meaning relative vertical movement) between the wheel 16 and the vehicle body, and the other end (wheel side). ) Is moved up and down with respect to the vehicle body.

  As shown in FIG. 3, the suspension device 20 includes a shock absorber 34 and an air spring 36. The shock absorber 34 is of a twin tube type in this embodiment, and is connected to the lower arm 32 at the lower end portion of the outer cylinder 42 constituting the main body 40 and is fixed to the vehicle body at the upper end portion of the hollow piston rod 44. The rod support 45 is fixedly supported. The piston rod 44 extends from a piston 48 that is fluid-tight and slidably fitted in the inner cylinder 46 of the main body 40, and an orifice provided in the piston 48 is moved when the piston 48 moves. Damping force is generated by the flow of oil.

  The shock absorber 34 has a variable damping force. A passage resistance adjusting mechanism 50 for changing the passage resistance of the oil by changing the area of the orifice is disposed below the piston 48 in order to adjust the damping force. The passage resistance adjusting mechanism 50 is formed by an orifice forming member 52 in which an orifice that allows oil to pass along the upper and lower sides of the piston is formed, and the orifice forming member that is provided so as to be rotatable about an axis and changes in the rotational position. And a shutter member 54 for changing the area of the orifice. On the other hand, a control rod 56 is inserted into the hollow piston rod 44, and an upper end portion of the control rod 56 is connected to an electric motor 58 (which is a step motor in this embodiment). A shutter member 54 is connected to the lower end of the control rod 56. Then, the rotational position of the shutter member 54 is changed by the electric motor 58 so that the magnitude of the damping force is changed. That is, the shock absorber 34 of the present embodiment is a damping force generating mechanism that can change the magnitude of the damping force with respect to the approach and separation between the wheel 16 and the vehicle body.

  The air spring 36 includes an air chamber 60 fixed to the piston rod 44 of the shock absorber 34 and an air piston 62 fixed to the main body 40 of the shock absorber 34. The air chamber 60 and the air piston 62 are connected by an elastically deformable diaphragm 64 so as to be able to approach and separate while maintaining airtightness, and the volume in the air spring 36 is reduced according to the approach and separation. The elastic force is increased and decreased.

3. Stabilizer device.
Each of the front and rear stabilizer devices 22 includes a stabilizer bar 70 connected to a lower arm 32 (see FIG. 2) that supports the left and right wheels 16 at both ends. The stabilizer bar 70 is divided at the center, and includes a pair of stabilizer bar members as a pair of left and right bar members, that is, a right stabilizer bar member 72 and a left stabilizer bar member 74. The pair of stabilizer bar members 72 and 74 are connected to each other via an actuator 80 so as to be relatively rotatable. Generally speaking, in the stabilizer device 22, the actuator 80 causes the left and right stabilizer bar members 72 and 74 to rotate relative to each other. Accordingly (see the arrows in FIG. 1 and the dotted line arrow), the roll amount of the vehicle body is suppressed by changing the twist amount per roll amount of the entire stabilizer bar 70. FIG. 2 shows one of the right stabilizer bar member 72 and the left stabilizer bar member 74.

  Each of the stabilizer bar members 72 and 74 is divided into a torsion bar portion 90 that extends substantially in the vehicle width direction and an arm portion 92 that is integrated with the torsion bar portion 90 and that intersects with the torsion bar portion 90 and extends generally forward or rearward of the vehicle. be able to. The torsion bar portion 90 of each stabilizer bar member 72, 74 is rotatably supported by a support member 96 fixedly provided on a stabilizer device disposition portion 94 that is a part of the vehicle body at a location close to the arm portion 92. Are arranged coaxially with each other. Between the end portions (end portion on the center side in the vehicle width direction) of the torsion bar portions 90, the above-described actuator 80 is disposed. As will be described in detail later, the end portions of the torsion bar portions 90 are Are connected to the actuator 80. On the other hand, the end portion of the arm portion 92 (the end portion opposite to the torsion bar portion 90 side) is connected to a stabilizer bar connecting portion 98 provided in the lower arm 32 so as to be relatively rotatable therewith.

  As schematically shown in FIG. 4, the actuator 80 includes an electric motor 100 and a speed reducer 102 that decelerates the rotation of the electric motor 100. The electric motor 100 and the speed reducer 102 are provided in a housing 104 that is an outer shell member of the actuator 80. The housing 104 is held by a stabilizer device mounting portion 94 provided on the vehicle body by a housing holding member 106 so as to be rotatable and immovable in the axial direction (substantially in the vehicle width direction). As can be seen from FIG. 2, each of the two output shafts 110 and 112 is disposed so as to extend from both ends of the housing 104. The ends of the output shafts 110 and 112 extending from the housing 104 are connected to the ends of the stabilizer bar members 72 and 74 so as not to rotate relative to each other by serration fitting. As can be seen from FIG. 4, one output shaft 110 is fixedly connected to the end of the housing 104, and the other output shaft 112 is disposed so as to extend into the housing 104. In addition, it is supported so as to be rotatable with respect to the housing 104 and immovable in the axial direction. One end of the output shaft 112 existing in the housing 104 is connected to the speed reducer 102, as will be described in detail later. The output shaft 112 also serves as the output shaft of the speed reducer 102. .

  The electric motor 100 includes a plurality of stator coils 114 fixedly arranged on one circumference along the inner surface of the peripheral wall of the housing 104, a hollow motor shaft 116 rotatably held in the housing 104, and a motor. It includes a permanent magnet 118 that is fixedly arranged on one circumference so as to face the stator coil 114 on the outer circumference of the shaft 116. The electric motor 100 is a motor in which the stator coil 114 functions as a stator and the permanent magnet 118 functions as a rotor, and is a three-phase DC brushless motor.

  The speed reducer 102 includes a wave generator (wave generator) 120, a flexible gear (flex spline) 122, and a ring gear (circular spline) 124. Also called). The wave generator 120 includes an elliptical cam and a ball bearing fitted on the outer periphery thereof, and is fixed to one end of the motor shaft 116. The flexible gear 122 has a cup shape in which the peripheral wall portion can be elastically deformed, and a plurality of teeth are formed on the outer periphery on the opening side of the peripheral wall portion. The flexible gear 122 is connected to and supported by the output shaft 112 described above. More specifically, since the output shaft 112 passes through the motor shaft 116 and the bottom portion of the flexible gear 122 is fixed to the end portion extending from the motor shaft 116, the flexible gear 122 and the output shaft 112 are connected. is there. The ring gear 124 is generally formed in a ring shape and has a plurality of teeth (a slightly larger number than the number of teeth of the flexible gear, for example, two more) than the number of teeth of the flexible gear, and is fixed to the housing 104. The flexible gear 122 is elastically deformed into an elliptical shape with a peripheral wall portion fitted on the wave generator 120, and meshes with the ring gear 124 at two positions located in the major axis direction of the ellipse, and does not mesh at other positions. It is said that. When the wave generator 120 rotates once (360 degrees), that is, when the motor shaft 116 of the electric motor 100 rotates once, the flexible gear 122 and the ring gear 124 are relatively rotated by the difference in the number of teeth. Since the harmonic gear mechanism has a known configuration, detailed illustration of the speed reducer 102 is omitted, and the description is limited to this level.

  From the above configuration, when the electric motor 100 is rotated, that is, when the actuator 80 is operated, the right stabilizer bar member 72 and the left stabilizer bar member 74 are rotated relative to each other (specifically, their respective torsion bars are The end portion of the portion 90 is relatively rotated), and one stabilizer bar 70 constituted by the right stabilizer bar member 72 and the left stabilizer bar member 74 is twisted. The elastic force generated by twisting the stabilizer bar 70 acts as a force for suppressing the roll, that is, a roll suppressing moment, by moving the left and right wheels 16 and the vehicle body closer to or away from each other. That is, in the present stabilizer device 22, the amount of twist of the stabilizer bar 70 per roll amount of the vehicle body is changed by the operation of the actuator 80, and the magnitude of the roll suppression moment with respect to the roll amount of the vehicle body, that is, the apparent rigidity is changed. Thus, the apparatus is configured to change the roll suppression effect.

  The actuator 80 is provided with a motor rotation angle sensor 130 for detecting the rotation angle of the motor shaft 116, that is, the rotation angle of the electric motor 100, in the housing 104. The motor rotation angle sensor 130 is mainly composed of an encoder in the actuator 80, and the detected value is used for switching the energized phase of the electric motor 100 and the relative values of the left and right stabilizer bar members 72 and 74. Used to acquire the rotation angle (relative rotation position).

4. Electronic control unit.
As shown in FIG. 1, the suspension system 10 includes a suspension device 20 and a stabilizer device 22, more specifically, an electronic control unit (ECU) 200 (hereinafter simply referred to as “ECU 200”) that is a control device that controls the operation of the actuator 80. May have). The ECU 200 is mainly configured by a computer having a CPU, a ROM, a RAM, and the like. In addition to the motor rotation angle sensor 130 described above, the ECU 200 includes an operation angle sensor 210 for detecting an operation angle of a steering wheel, which is an operation amount of a steering operation member as a steering amount, a vehicle travel speed (hereinafter referred to as “vehicle speed”). And a lateral acceleration sensor 214 for detecting an actual lateral acceleration that is a lateral acceleration actually generated in the vehicle body. (In FIG. 1, they are represented as “θ”, “δ”, “V”, and “G”, respectively).

  ECU 200 is also connected to inverter 134, and ECU 200 transmits various control commands to inverter 134, whereby drive power is supplied from inverter 134 to actuator 80. Furthermore, the ECU 200 is connected to the electric motor 58 via the drive circuit, and the drive power is supplied from the drive circuit to the electric motor 58 when the ECU 200 transmits a command to change the damping force to the drive circuit. Is done. The ECU 200 includes a storage unit 230 that includes a ROM, a RAM, and the like. The storage unit 230 includes programs such as a roll suppression control program and a roll suppression effect complementing program that will be described later, roll suppression, and the like. Various data relating to the control of these are stored.

  The stabilizer system 10 includes two stabilizer devices 22 on the front wheel side and the rear wheel side. The two stabilizer devices 22 are individually controlled according to the set roll rigidity distribution, and each of the stabilizer devices 22 is controlled. Under the control, each generates a predetermined roll restraining moment. In the following description, the two stabilizer devices 22 have the same configuration in consideration of simplification unless otherwise specified. We will treat them as a single unit.

4.1. Roll suppression control.
Below, control of the actuator 80 by ECU200 for exhibiting a suitable roll suppression effect by the stabilizer apparatus 14 is demonstrated in detail. The ECU 200 controls the actuator 80 by repeatedly executing the roll suppression control program at an extremely short time interval, and changes the relative rotation amount of the pair of stabilizer bar members 72 and 74 to exert an appropriate roll suppression effect. . The roll suppression control is performed by relatively rotating the pair of stabilizer bar members 72 and 74 so that the relative rotation amount of the pair of stabilizer bar members 72 and 74 becomes an amount corresponding to the control lateral acceleration Gy ^* described later. This is a control that generates an appropriate roll suppression effect. FIG. 5 shows a flowchart of the roll suppression control, and the roll suppression control will be described along the flowchart.

In step 11 (hereinafter, step 11 is abbreviated as “S11”, and the same applies to other symbols), the vehicle speed V and the steering wheel operation angle δ (in the neutral state, that is, in the case where the straight operation state is 0) , The angle deviation from the state) is acquired based on the detection values of the vehicle speed sensor 212 and the operation angle sensor 210, respectively. In this embodiment, the control lateral acceleration Gy ^{*, which} is a roll moment estimated physical quantity, is acquired in order to determine the target rotation amount of the pair of stabilizer bar members 72 and 74 during the roll suppression control. The control lateral acceleration Gy ^* is calculated based on the so-called estimated lateral acceleration Gyc estimated based on the operation angle δ and the vehicle speed V and the actual lateral acceleration Gy detected by the lateral acceleration sensor 214 in the present embodiment. Obtained by an expression.
[Formula 1] Control lateral acceleration Gy ^* = K ₁ · Gyc + K ₂ · Gyr
In this embodiment, K ₁ and K ₂ are coefficients set in advance so that the roll can be effectively suppressed based on the result of the running test. Further, these K ₁ and K ₂ are, for example, values set so that the sum thereof becomes 1, or values that change based on the vehicle speed V, the operation angle δ, the actual lateral acceleration Gyr, and the like. You can also.

In S12, a target rotation amount θ ^* that is a target value of the relative rotation amount of the pair of stabilizer bar members 72 and 74 is determined based on the control lateral acceleration Gy ^* . In other words, the target rotation amount θ ^* set according to the control lateral acceleration Gy ^* is stored as a target rotation amount map in the storage unit 230 of the ECU 200, and the target rotation amount according to the control lateral acceleration Gy ^* is determined from the target rotation amount map. is the target rotation amount theta ^* determination is made by the amount of rotation theta ^* is read. Thereafter, in S13, the actual relative rotation amount θ of the pair of stabilizer bar members 72 and 74 is acquired based on the detection value of the motor rotation angle sensor 130.

In S14, in order to operate the actuator 80 so as to reduce the deviation Δθ between the relative rotation amount θ and the target rotation amount θ ^* , a target power value that is an appropriate power value supplied to the electric motor 100 is determined. . After the target power value is determined, a command is issued to the inverter 104 in S15. That is, the inverter 104 supplies the electric motor 100 with electric power having a magnitude equal to the target electric power value. As a result, the pair of stabilizer bar members 72 and 74 are rotated relative to each other, and an appropriate roll suppressing effect is exhibited. With the above, one process of roll suppression control is completed.

4.2. Roll suppression effect supplement program.
In the suspension system 10, the roll restraining control program is executed as described above, so that the stabilizer device 22 exhibits an appropriate roll restraining effect. However, the roll restraining effect (specifically, the ability to restrain the roll generated according to the amount of twist of the stabilizer bar 70) is insufficient when the roll direction of the vehicle body is switched from one of the left and right during slalom traveling, etc. There is a case. That is, when the vehicle body rolls to the left or right, the pair of stabilizer bar members 72 and 74 are rotated relative to each other in the rotational direction that suppresses the roll, and then rolled to the other left and right by the operating resistance of the actuator 80 or the like. One reason is that the relative rotation amount of the pair of stabilizer bar members 72 and 74 is delayed until the time is zero. Due to the return delay, the absolute value of the deviation Δθ between the relative rotation amount θ and the target rotation amount θ ^* of the pair of stabilizer bar members 72 and 74 becomes relatively large when the vehicle body rolls to the other side of the left and right. In many cases, the actual relative rotation amount θ becomes smaller than the target rotation amount θ ^* and a time lag until the deviation Δθ becomes equal to or less than the set value becomes relatively long. That is, it is considered that the roll suppressing effect is insufficient because the twist amount of the pair of stabilizer bar members 72 and 74 per roll amount of the vehicle body is insufficient. The speed reducer 102 provided in the actuator 80 of the present embodiment has a large reduction ratio (for example, 200: 1) and a relatively large operating resistance, so that a return delay of the pair of stabilizer bar members 72 and 74 tends to occur. is there. Therefore, for example, even when the pair of stabilizer bar members 72 and 74 are in the relative rotation permissible state, specifically, no electric power is supplied to the electric motor 100 and the electrical connection with the inverter 134 is interrupted. Even if each phase of the electric motor 100 is in an open state, the actuator 80 generates a considerable operating resistance with respect to the relative rotation of the pair of stabilizer bar members 72 and 74.

  In the present embodiment, a roll suppression effect supplement program is executed by the ECU 200 in order to cope with the shortage of the roll suppression effect due to the return delay of the relative rotation of the pair of stabilizer bar members 72 and 74 described above. The roll suppression effect supplement program is a program that appropriately suppresses the roll by increasing the damping force of the shock absorber 34 when the roll suppression effect is insufficient due to the return delay. Flow charts of the roll suppression effect supplement program are shown in FIGS. 6 to 8, and the roll suppression effect supplement program will be described along the flowchart.

  In S20, the vehicle speed V, the steering wheel operating angle δ, the operating speed δv, and the estimated lateral acceleration Gyc are acquired. The operation speed δv is determined based on the change in the operation angle δ from the current time to the set time. The estimated lateral acceleration Gyc is acquired based on the operation angle δ and the vehicle speed V. In this embodiment, the right operation angle δ from the neutral position is a positive value, the left operation angle δ is a negative value, the right operation speed δv is a positive value, and the left operation speed δv is a negative value. Is in value. In S21, it is determined whether or not a command for increasing the damping force of a shock absorber 34 described later has been issued. In the determination, if the flag F1 indicating whether or not a command to increase the damping force has been issued is ON, a command to increase the damping force has been issued, the process proceeds to circle 1, and the processes of S22 and subsequent steps are skipped. As will be described later, processing for canceling the increase in damping force (see FIG. 8) is performed at an appropriate time. When the flag F1 is OFF, the processing from S22 is performed. When this program is executed for the first time, the flag F1 is turned off. Similarly, other flags F2 and F3 described later are also turned off.

  In S22 to S25, it is detected whether or not a switchback operation (operation to approach the neutral position) has been performed after the turn that may cause the roll suppression effect to be insufficient. That is, (a) a turning operation is performed (S22: | operation angle δ |> setting angle A), (b) a switching operation is performed at a certain operation speed (S23), and (c) lateral acceleration due to the turning is increased. When the state is somewhat large (S24), it is determined that the switchback operation has been performed after the turn that may cause the roll suppression effect to be insufficient. And the flag F2 which shows that the switchback operation was made after the turn which may cause the shortage of a roll suppression effect is turned ON (S25). In this embodiment, when the absolute value of the operation speed δv of the operation approaching the neutral position is larger than the set speed B1, it is determined that the switch back operation is being performed (S23). This is because when the operation speed δv of the switchback is sufficiently low, it is considered that the roll suppressing effect is hardly insufficient. In other words, in this processing, the estimated roll moment physical quantity at the time of the switchback operation is the estimated lateral acceleration Gyc at the time when the switchback operation is performed at an operation speed at which the twisting return of the stabilizer bar is likely to occur. If it is determined in S24 that the estimated lateral acceleration Gyc exceeds the set value G1, it is determined that the roll suppression effect is likely to be insufficient. That is, when the estimated lateral acceleration Gyc exceeds the set value G1, a considerable degree of roll moment is applied to the vehicle body by turning, and the pair of stabilizer bar members 72 and 74 are relatively relative to each other to suppress the roll. It is presumed that the roll has been rotated, and when the roll direction is switched by a subsequent steering operation, it is considered that the roll suppression effect is likely to be insufficient. Note that it is also possible to omit the process of S22 and determine whether or not the roll suppression effect can be insufficient based on the roll moment estimated physical quantity at the time of the switch back operation by the processes of S23 and S24. The flag F2 indicating that the turning to such an extent that the roll suppressing effect is insufficient in S25 is used for subsequent determination.

  Even if the flag F2 is once turned ON, in S26 and S27, when an additional operation (operation to move away from the neutral position) is performed, or when the operation speed δv is very low even in the switchback operation The flag F2 is turned off. This is because even if the turning to such an extent that the roll suppressing effect is insufficient is once performed, the roll suppressing effect is hardly generated unless the switchback operation is continuously performed. In addition, even if the switchback operation is performed, if the operation speed δv is sufficiently low (the absolute value is equal to or less than the set speed B2), the return delay of the relative rotation of the pair of stabilizer bar members 72 and 74 is unlikely to occur. The set speed B2 is very small and is smaller than the set speed B1.

  In S31 to S36 (FIG. 7), it is determined whether or not the operation angle δ exceeds the neutral position by the steering operation. Specifically, when the sign of the operation angle δold when the absolute value of the operation angle δ exceeds a relatively small set angle C (for example, about several degrees) and the sign of the current operation angle δ are reversed, that is, When the signs are different from each other, it is determined that the operation angle δ exceeds the neutral position (S35). In this embodiment, after the flag F3 indicating that the absolute value of the operation angle δ has once exceeded the set angle C is turned ON (S32, S34), it is not determined that the neutral position has been exceeded. (S31). That is, in a state where the absolute value of the operation angle δ does not exceed the set angle C, that is, in a state where the flag F3 is OFF, the steering operation is performed almost in the straight position and near the neutral position, and the roll suppression effect is insufficient. It is because it is hard to produce. That is, the range where the absolute value of the operation angle δ does not exceed the set angle C is a dead zone. If it is determined that the neutral position has been exceeded, the flag F3 is turned OFF, and it is not determined whether the neutral position has been exceeded until the absolute value of the operation angle δ exceeds the set angle C again. Has been.

  By the determination in S37, the process of complementing the shortage of the roll suppression effect in S38 and subsequent steps is skipped unless the vehicle speed V is higher than the set speed D and the flag F2 is ON. This is because when the vehicle speed V is sufficiently low, or when the vehicle is not turned to such an extent that the roll suppression effect is insufficient (when F2 is OFF), the roll suppression effect is unlikely to occur. is there.

  When the determination in S37 is YES, in S38, there is an insufficient amount of the roll suppression effect, specifically, an insufficient amount of force to suppress the roll due to an insufficient amount of twist of the pair of stabilizer bar members 72 and 74. To be acquired. In the present embodiment, the shortage of the roll suppression effect is acquired based on the operation speed δv. Specifically, the relationship between the operation speed δv and the insufficient roll suppression effect is stored in the storage device 230 as a roll suppression effect shortage map schematically shown in FIG. 9, and the operation speed δv in the process of S38. The shortage of the roll suppression effect corresponding to is read out. The roll suppression effect deficiency map may be a linear approximation of the map of FIG. 9 as schematically shown in FIGS. 10 and 11.

  In S39, an increase in the damping force of the shock absorber 34 on the turning outer wheel side is acquired based on the shortage of the roll suppression effect acquired in the process of S38. Specifically, the relationship between the shortage of the roll suppression effect and the increase of the damping force is stored as a map (not shown) in the storage device 230, and the increase of the damping force according to the shortage of the roll suppression effect. Minutes are read. Incidentally, for example, when the current operation angle δ is a positive value, the turning outer wheel side is steered to the right, so the turning outer wheel side is the left side. That is, based on the sign of the operation angle δ, it is possible to acquire which side of the turning outer wheel is left or right. The relationship between the operation speed δv and the increase in damping force is stored in the storage device 230 as a map (not shown), and the processing in S38 and S39 is performed to obtain the increase in damping force based on the operation speed δv. It is also possible to use one process.

  In S40, the ECU 200 instructs the drive circuit to increase the damping force of the shock absorber 34 on the turning outer wheel side in accordance with the increase in the damping force. Then, electric power is supplied by the drive circuit, and the shutter member 52 is rotated by an angle corresponding to the increase in the damping force by the electric motor 58, so that the damping coefficient of the shock absorber 34 is increased. Thereafter, in S41, a flag F1 indicating that a damping force increase command has been issued is turned ON.

  When this program is executed with the flag F1 turned on, the determination of S21 described above becomes NO, and the processing after S42 (FIG. 8) is executed. Since the flag F1 is turned on when turning from one side to the other on the left and right sides is started, normally, the flag F1 is continuously turned on for a while after the flag F1 is turned on (away from the neutral position). Direction operation). In this embodiment, the increase of the damping force is canceled when the increase operation is finished and the return operation is started, that is, when the operation is started in the direction approaching the neutral position (S42). A command is issued (S43). Although different from the determination conditions at the time of the switch back operation in S23 described above, in this process, the determination conditions are set as described above in order to detect a state in which the roll amount of the vehicle body is almost not increased. The determination condition at the time of the switchback operation in this process is a condition for detecting the time point when the switchback operation is started. When a release command is issued from the ECU 200 to the drive circuit in S43, electric power is supplied from the drive circuit to the electric motor, and the shutter member 52 is reversely rotated by an angle corresponding to the increase in the damping force, so that the shock on the turning outer wheel side is reduced. The attenuation coefficient of the absorber 34 is returned to the value before the increase. In S44, after the flag F1 indicating that a damping force increase command has been issued is turned OFF, the process proceeds to circle 3 (to FIG. 7), and one execution of this program is completed.

  In the present embodiment, “the steering operation crossing the neutral position” has been detected by the portion of the ECU 200 that executes the processes of S22 to S37. Then, the process of “increasing at least one damping force of the pair of damping force generation mechanisms” is performed by the part that executes the processes of S38 to S40 of the ECU 200. For example, even if at least one of the processing of S22 to S27 and the determination regarding the vehicle speed V of S37 is omitted, it can be detected that the steering operation across the neutral position has been performed. By reducing the determination conditions, the roll suppression supplement program can be simplified. On the other hand, if the number of determination conditions is increased, the process of “increasing the damping force” is performed in a state in which there is a relatively high possibility that the roll suppression effect will decrease or the degree of decrease in the roll suppression effect is large. In a state where the possibility that the roll suppression effect is reduced is relatively low, or in a state where the degree of reduction in the roll suppression effect is relatively small, the process of “increasing the damping force” is difficult to be performed.

  The suspension system 10 is configured such that the ECU 200 increases the damping force of at least one of the pair of damping force generation mechanisms according to the vehicle speed by executing the determination regarding the vehicle speed V in S37. In addition, the suspension system 10 increases the damping force of at least one of the pair of damping force generation mechanisms according to the roll moment estimated physical quantity at the time of the switching back operation by the ECU 200 executing the processes of S22 to S27. It is configured as follows. Furthermore, the suspension system 10 is configured to increase the damping force of at least one of the pair of damping force generation mechanisms in accordance with the operation speed when the ECU 200 executes the process of S38. When the ECU 200 executes this program to perform slalom traveling, the roll amount of the vehicle body is not more than a set value (for example, the absolute value of the roll angle is about several degrees), that is, the vehicle body is The effect of reducing the roll speed in a state where the turning direction is switched after rolling to one side and starting to roll to the other side of the left and right can be expected.

5. Other.
In this embodiment, only the damping force of the shock absorber 34 on the turning outer wheel side is increased, but the damping force of the left and right shock absorbers 34 can be increased. It is also possible to increase only the damping force of the shock absorber 34 on the turning inner ring side. Further, although different from the present embodiment, the damping force of the shock absorber 34 may be increased or decreased by other active control such as pitching control, control according to road surface conditions (good road, bad road), for example. is there. In such a case, for example, it is possible to perform control so that the amount of increase in the damping force that compensates for the lack of the roll suppression effect is added to the damping force determined by other active control.

It is a figure which shows typically the suspension system which is an Example of claimable invention. It is a figure which shows a part of said suspension system typically. It is a figure which shows the cross section of the suspension apparatus of the said suspension system. It is a figure which shows the cross section of the actuator of the said suspension system. It is a figure which shows the flowchart of the roll suppression control performed by the electronic control unit of the said suspension system. It is a figure which shows the 1st part of the flowchart of the roll suppression supplement program performed by the said electronic control unit. It is a figure which shows the 2nd part of the flowchart of the roll suppression supplement program performed by the said electronic control unit. It is a figure which shows the 3rd part of the flowchart of the roll suppression supplement program performed by the said electronic control unit. It is a figure which shows typically the roll suppression effect deficiency map memorize | stored in the memory | storage part of the said electronic control unit. It is a figure which shows typically the example of the roll suppression effect deficiency map different from the above. It is a figure which shows typically the example of the roll suppression effect deficiency map further different from the above.

Explanation of symbols

10: Vehicle suspension system 16: Wheel 20: Suspension device 22: Active stabilizer device 34: Shock absorber (damping force generating mechanism) 36: Air spring 50: Passing resistance adjusting mechanism 52: Orifice forming member 54: Shutter member 70: Stabilizer Bar 72: Right stabilizer bar member (right bar) 74: Left stabilizer bar member (left bar) 80: Actuator 90: Torsion bar portion 92: Arm portion 100: Electric motor (electromagnetic motor) 102: Reducer 104: Housing 120 : Wave generator (wave generator) 122: Flexible gear (flex spline) 124: Ring gear (circular spline) 130: Motor rotation angle sensor 200: Electronic control unit [ECU] θ: Motor rotation angle δ : Operating angle δv: Operating speed V: Vehicle speed G: Lateral acceleration

Claims (4)

A pair of damping force generating mechanisms provided corresponding to each of the left and right wheels and capable of changing the magnitude of the damping force with respect to the approach and separation between each of the left and right wheels and the vehicle body;
The stabilizer bar connected to each of the left and right wheels, and the amount of twist of the stabilizer bar per roll amount of the vehicle body according to the roll moment estimated physical amount, which is a physical amount capable of estimating the magnitude of the roll moment applied to the vehicle body A suspension system comprising a stabilizer device including an actuator that changes the roll suppression effect of the vehicle body by the stabilizer bar by changing
A vehicle suspension system configured to increase a damping force of at least one of the pair of damping force generation mechanisms when a steering operation is performed across a neutral position. The suspension system is
The damping force is configured to increase at least one of the pair of damping force generation mechanisms in accordance with a degree of return delay of twisting of the stabilizer bar when a steering operation is performed across a neutral position. The vehicle suspension system described in 1. The suspension system is
3. The vehicle suspension system according to claim 1, wherein the vehicle suspension system is configured to increase a damping force of at least one of the pair of damping force generation mechanisms according to an operation speed. The actuator is
An electromagnetic motor serving as a driving force source, and a speed reducer that decelerates and outputs the driving rotation of the electromagnetic motor input to itself,
The stabilizer bar is
Each has a shaft-like torsion bar portion rotatably held on the vehicle body and an arm portion extending from one end portion of the torsion bar portion in a direction crossing the rotation axis, and a starting end portion of the torsion bar portion And including a pair of left and right bar members connected to the actuator,
5. The twist amount of the stabilizer bar per roll amount is changed by changing a relative rotation amount of each of the leading end portions of the pair of bar members. Vehicle suspension system.

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