JPH02109710A - variable suspension device - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a variable rear suspension device for a two-wheeled motor vehicle.

[Prior Art] Various variable rear suspension installations are known, such as vehicle speed, sprung load, unsprung load, bank angle,
There is a device that controls the damping force of the rear suspension by detecting the throttle opening, gear position, etc.
(See Publication No. 3-2787). In this example, the damping force of the damping force variable damper is controlled in order to prevent the occurrence of the skort phenomenon, in which the vehicle body sags during acceleration, etc., and the damping force is controlled based on the predicted acceleration based on the detected quantities or The damping force is controlled based on the acceleration of

[Problems to be Solved by the Invention] Incidentally, the cause of the posture change such as the skort phenomenon is the skort force (denoted as F) generated by the driving force or braking force acting on the rear wheels and the anti-scort force (denoted as F). F,
, ), ΔF=F, -F, . . .
...■ means that the force ΔF (in the present invention, referred to as rear axle conversion additional reaction force) acts as an extra force on the rear axle due to chain tension,
This rear axle converted additional reaction force ΔF becomes a force Δf (also referred to as additional reaction force) that acts on the rear suspension in a constant proportional relationship.

Now, considering the compression stroke of the rear suspension when passing through a gap during driving or braking, when the additional reaction force Δf is acting in the direction of extension, the rear suspension becomes stiff, and conversely, it is acting in the direction of contraction. If you do it, it will become softer.

However, all of the conventional variable damping force dampers, including the ones mentioned above, have a skort force F and an anti-scort force F a
Since ll is not used as the basic control quantity, it is not possible to perform damping force control corresponding to the additional reaction force Δf when passing through the gap, so the attitude change when passing the gap becomes large, and it is difficult to optimize the attitude change or roughly. Arbitrary and easy attitude control is not possible, and as a result, it becomes difficult to improve the road surface followability of the rear wheels and the rear wheel traction.

Therefore, it is desirable to control the damping force of the damper so that there is no influence of the additional reaction force Δf when passing through the gap.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a variable rear suspension device that can achieve optimal posture changes even when passing through a gap during driving or braking by performing damping force control based on the additional reaction force Δf. .

[Means for Solving the Problems] In order to solve the above problems, a variable rear suspension device according to the present invention includes a variable damping force type damper, a driving force sensor for detecting driving force or braking force, and a front A front stroke sensor to detect the stroke amount of the suspension, a rear arm angle sensor to detect the angle the rear arm makes with the horizontal line, and skort force and anti-scort determined by geometric calculations based on the detection signals of these sensors. and a control circuit that determines a difference between the damping force and the damping force, determines a damping force change amount based on this difference, and further outputs a control signal for adjusting the damping force of the damper based on the damping force change amount. It is characterized by

[Operation of the invention] Fig. 1 shows the conceptual shape of a two-wheeled motor vehicle in order to define the various quantities described below. IFC the center position (the intersection of the tension of chain 2 and each extension line of rear arm 3)
, wheelbase statement, ground clearance of CG is h, rear arm angle (angle with horizontal line of rear arm 3) is ψ, horizontal distance between rear axle 4 and IFC is X, ground clearance of IFC is Y, and roughly the capacity is Define as follows.

F: Suspension reaction force at rest due to the rear suspension 5 converted to the rear axle 4 F: Dynamic suspension reaction force during driving (or braking) converted to the rear axle 4 Fr: Rear wheel l caused by the chain 2 The driving force (or braking force, the same applies hereinafter) transmitted to wtr: unsprung weight, W: total weight tan α knee Here, the relationship between each suspension reaction force is given by: Therefore, if we define K1=E+Hiro
Each multiplied by the driving force Fr is the skort force F.
8 and anti-scort force F, 1. Therefore, the formula becomes as follows.

Fpa-Fa +Fr (Kl-2)'...
・■=Fa+F, -Fa□ Here, from equation 0, Fpa=Fa+ΔF Therefore, ΔF=F,, (2 for Kl -) ・・・・■
Further, in FIG. 2 which conceptually shows the vicinity of the rear suspension 5, the wheel ratio Kw is set to L ΔF K·=1. If we define “Af”, it becomes as follows.

Δf=1−XΔF...■ w Here, W and Wtr are constants, and the other h, sentence,
and Y can be found once each position of CG and IFC is determined.

The positions of CG and NFC are the front suspension 7 and rear suspension 5 supporting the front wheels 6.
It is determined by detecting the stroke amount. Of these, the stroke amount of the rear suspension 5 is determined by the rear arm angle ψ, and the driving force Fr and the stroke amount of the front suspension 7 can also be calculated by sensors. Therefore, by detecting the rear arm angle ψ, the driving force Fr, and the stroke amount of the front suspension 7, the rear axle converted additional reaction force ΔF and additional reaction force Δf can be determined by geometric calculation from the above equations.

Note that during braking, only the direction of the driving force Fr changes, and the damping force can be controlled in the same way as above.

Therefore, according to the variable rear suspension device of the present invention, when the motorcycle enters the gap, the control circuit detects the skort suspension based on the detection signals input from the driving force sensor, the front stroke sensor, and the rear arm angle sensor. F8 and anti-scort force Fag, rear axle conversion additional reaction force ΔF, and additional reaction force Δf in a proportional relationship thereto are calculated, and based on this additional reaction force Δf, the damping force change amount is determined, and this damping force change amount is calculated. Outputs the corresponding control signal. The damper is adjusted by this control signal to increase or decrease the damping force. As a result, the additional reaction force Δf is canceled and the damping force of the damper when passing through the gap is adjusted.

For example, if an additional reaction force Δf is acting on the rebound side during the contraction process of the tamper when passing through a gap during braking, reducing the damping force will improve the operability of the damper and prevent it from jumping or other postures. On the other hand, if additional reaction force Δf acts on the compression side during the compression process during driving, the damping force is increased to stiffen the rear suspension and similarly reduce the attitude change.

[Example] Hereinafter, one embodiment will be described based on the drawings.

FIG. 3 is a system diagram for controlling the damping force of the rear suspension 5. The rear suspension 5, whose internal structure is shown in cross section in the figure, consists of a damper 8 and a suspension spring 9.

The damper 8 is an example of a known damping force variable damper,
A cylinder 10, a piston 11 slidably housed inside the cylinder, a cylindrical piston rod 12 having one end fixed to the piston 11 and extending downward, and a piston rod 12.
A bottom case 13 is provided at the lower end of the piston rod, a rod valve 14 is fitted into a through hole formed in the axial direction of the piston rod 12 so as to be movable forward and backward, and the rod valve 14 is screwed into a male screw portion formed at the lower end of the rod valve 14. Gear 15a, gear 15b meshing with this,
15c, a reversible motor 16 that rotates the gear 15b, a rotary potentiometer 17 that rotates integrally with the gear 15c, and the like. In addition, gears 15a, 15b, 15c,
The reversible motor 16 and rotary potentiometer 17 are housed within the bottom case 13. Further, the suspension spring 9 is supported by spring receivers disposed on the outer peripheries of the bottom case 13 and the cylinder 10 between seats.

Further, the inside of the cylinder 10 is divided into an upper chamber 10a and a lower chamber 10b by the piston 11, and these upper chamber 10a and lower chamber 10b are communicated with the piston 11, and a reed valve allows hydraulic oil to pass only in opposite directions. Through hole 11a
, llb are formed in the axial direction.

Further, the upper end of the through hole of the piston rod 12 forms an orifice 12a, and the through hole 18 that communicates with this forms an orifice 12a.
1 and the piston rod 12 in the radial direction, and the orifice 12a and the through hole 18 are formed by the rod valve 14.
The flow path area between the two is variable.

Furthermore, a sub-tank 19 is attached to the upper part of the cylinder 10. The sub-tank 19 is divided into an air chamber 19a filled with nitrogen gas or the like and an oil chamber 19b, and the oil chamber 19b communicates with the upper chamber 10a of the cylinder 10 through a pipe 19c.

Further, the piston 19d and a relief valve 19e that closes the passage formed therein are accommodated in the conduit 19c. The return spring 19f of the relief valve 19e is connected to a solenoid 1 provided at the end of the pipe line 19c.
It is supported by a shaft 19h weighing 9 g and is given a set load.

A control circuit 20 for controlling the damping force of the damper 8 includes an arithmetic processing section 21, a driving section 22, a comparator 23, and the like. A driving force sensor 24, a rear arm angle sensor 25, and a front stroke sensor 26 are connected to the calculation processing section 21, respectively.

However, the rear arm angle sensor 25 is also connected to the comparator 23.

A rear arm angle sensor 25 and a potentiometer 17 of the damper 8 are connected to the comparator 23, and the arithmetic processing section 21 is turned on or off depending on the voltage difference between the two. In addition, in FIG. 3, in order to facilitate the explanation of the connection relationship with the comparator 23,
In addition to the entire cross section of the damper 8, a partial cross section of the bottom case 13 in the Z direction is also shown.

FIG. 4 shows a specific example of the driving force sensor 24, in which an electrode 28 is integrally rotated by a bolt 29 at the shaft end of a counter shaft 27 to which the drive sprocket 2a (see FIG. 5) is spline-coupled. A strain gauge is installed as a driving force sensor 24 between the electrode 28 and the drive sprocket 2a.

On the other hand, a slip ring 31 is attached to the mission case 30, and is connected to a power source via a cord 32.
In addition, power is supplied to the electrode 28. Therefore, when a driving force is applied to the chain 2 by the drive sprocket 2a, the counter shaft 27 is twisted accordingly, and the amount of distortion is detected as a change in resistance value by a strain gauge that is the driving force sensor 24.

The relationship between the amount of strain γ and the torsional moment MT in the solid counter shaft 27 is given by πd2 MT=π−XGXγ (d: shaft diameter, G: shear modulus of elasticity).

Moreover, as shown in Fig. 5, this torsional moment MT
The relationship between and driving force Fr is M = 2! -XRXF.

(rt and r2 are the respective radii of the drive sprocket 2a and the driven sprocket 2b). Therefore, by measuring the amount of strain γ, the driving force F,
can be found. However, in reality, a calibration graph is created by previously measuring the relationship between the torque of the counter shaft 27 and the amount of distortion using an actual machine, and this is stored in the arithmetic processing section 21.

FIG. 6 is a diagram showing a specific example of the rear arm angle sensor 25, and this sensor is configured as a rotation potentiometer fixed to the vehicle body. This rotary potentiometer 25 is connected to the rear arm 3 via an arm 33, and the rear arm angle ψ is detected by the voltage change of the rotary potentiometer 25 that occurs as the rear arm 3 swings. By detecting the rear arm angle ψ, the rear axle 4
The stroke amount can be determined. In other words, the rear axle 4 when the rear suspension 5 is fully extended
If the position is 0 and the position at full stroke is S2, then
The stroke amount of the rear axle 4 is determined in accordance with the change in the rear arm angle ψ that swings around the pot point 2. The relationship between the voltage change of the rotary potentiometer 25 and ψ is measured in advance using an actual machine, a calibration graph is created, and this is stored in the arithmetic processing unit 21.

FIG. 7 is a diagram showing the specific side of the front stroke sensor 26, in which a sensor body configured as a stroke type potentiometer is attached to the upper tube 7a side of the front suspension 7, and a telescopic rod 34 is attached to the lower tube 7b side. be. As a result, when the upper tube 7a and the lower tube 7b relatively expand and contract,
The stroke change can be detected as a voltage change of the potentiometer.

Next, a damping force control method in this embodiment will be explained. When the detection signals of each sensor are input to the control circuit 20, the eighth
Processing is performed according to the block diagram shown in the figure. This will be explained below.

First, when the detection signals of each sensor are input, the arithmetic processing unit 21 calculates the driving force Fr based on the detection signal of the driving force sensor 24.
The rear arm angle ψ and the stroke amount of the front suspension are calculated based on the detection signals of the rear arm angle sensor 25 and front stroke sensor 26, and each position of CG and IFC is determined based on these. Furthermore, the values of each scale, l, X, Y, and tanψ (as well as tanθ and tanα) are calculated.

Next, using these quantities and constants W and Wtr, the values of □ for the skort ratio, 2 for the anti-scort ratio, and the difference between the two (2 for K□-) are calculated.

FIG. 9 is a graph showing the correlation between K work, K2, the difference between them (K, -2), and the stroke amount of the rear axle 4. As shown in FIG. 2, the stroke amount of the rear axle 4 is defined as the amount of movement between the maximum extension of the rear suspension 5 and the full O1 contraction of 82. From this graph, K1. It can be understood that 2 and the difference between the two (2 for K knee) are geometrically determined quantities. Also, (K
□-2) value is the stroke displacement SX of rear axle 4
Changes to negative or positive depending on.

Subsequently, the arithmetic processing unit 21 calculates the driving force Fr and (K.

- Calculate the rear axle equivalent additional reaction force ΔF using 2), and further calculate the additional reaction force Δf based on the rear axle equivalent additional reaction force ΔF using equation 0.

Thereafter, the arithmetic processing unit 21 determines the damping force change amount based on this additional reaction force Δf, and outputs a control signal to the drive unit 22. Note that the damping force change amount is determined by the additional reaction force Δf as necessary.
It can also be a value (ΔfXα) multiplied by an arbitrary coefficient α (α>0). This is the rear axle position and driving force F,
This means that the damping force change amount can be arbitrarily selected.

When the drive section 22 is turned on, the reversible motor 16 rotates in either forward or reverse direction. Along with this, the gear 15b rotates, and the gear 15a and gear 15c that mesh with it also rotate at the same time. When the gear 15a rotates, the threaded rod valve 14 moves forward or backward depending on the direction of rotation, and as a result, the orifice 12a is narrowed or loosened, changing its flow path cross-sectional area. damping force is adjusted.

Also, due to the rotation of the gear 15c, the potentiometer 17
voltage changes. This voltage is compared with the voltage of the rear arm angle sensor 25 in the comparator 23, and the result is constantly fed back to the arithmetic processing section 21. Arithmetic processing unit 2
1 performs calculation again based on the signals from the sensors 24 to 26 and the output signal from the comparator 23, determines an appropriate amount of attenuation, and rotates the reversible motor 16 by the required amount via the drive section 22. Thereafter, this process is repeated and the damping force is constantly adjusted.

In addition, when the rear wheel l is pushed up with an extremely large force when passing through a gap, the arithmetic processing unit 21 detects passing through the gap from the signal of the front stroke sensor 26, and the stroke amount at this time is abnormally large. When the predetermined condition is met, the solenoid 19g is turned on via the drive unit 22, the shaft 19h is moved backward, and the set load of the return spring 19f is reduced. As a result, even if the pressure in the upper chamber 10a of the cylinder 10 is lower than normal, the hydraulic oil in the upper chamber 10a is transferred to the oil chamber 10 of the sub-tank 19.
b, the damper 8 is easily compressed, and the rear part of the vehicle body is prevented from jumping up during braking. Thereafter, when the current to the solenoid 19g is cut off, the relief valve 19e closes the through hole by the return spring 19, which has returned to the normal set load.

FIG. 10 is a graph showing the relationship between the stroke of the rear axle 4 and the damping force, and shows that when the additional reaction force Δf is canceled, the damping force changes from the solid line to the dotted line.

Here, the sign change of the additional reaction force Δf with respect to the stroke displacement SX of the rear axle 4 is as shown in the following table.

That is, when the additional reaction force Δf<0, an excessive force acts to stretch the rear suspension 5, and when the additional reaction force Δf=0, no excessive force acts on the rear suspension 5. Further, when the additional reaction force Δf>0, it acts as an excessive force that tends to compress the rear suspension 5.

Therefore, for example, when passing through a gap with a braking force applied, if 0<S, <St, the additional reaction force Δf<O, so the damping force change amount (Δf or Δf
xα) to lower the damping force of the damper 8 and cancel the additional reaction force Δf of the rear suspension 5, the damping force shifts from the unadjusted state shown by the solid line to the adjusted state shown by the dotted line and decreases.

As a result, the piston speed of the damper 8 increases, instantly softening the rear suspension 5 and reducing posture changes.

Conversely, when passing through the gap while applying a driving force when S 1 < S If the amounts are added, the damping force of the damper 8 will shift from the solid line to the dotted line and increase, and the piston speed of the damper 8 will slow down. As a result, the additional reaction force Δf of the rear suspension 5 is canceled, so
It instantly becomes stiff and similarly reduces posture changes.

As a result of the above, good gap running performance can be achieved.
It provides better followability to the road surface and improves rear wheel traction.

[Effects of the Invention] According to the present invention, since the damping force is adjusted based on the skort force and the anti-scort force, an optimal suspension reaction force can be set when passing through a gap while applying a driving force or a control force. Therefore, the attitude change when passing through the gap can be minimized or optimized. Furthermore, the degree of change in driving posture can be freely and easily set.

Therefore, it exhibits good gap running performance and improves road surface followability, resulting in improved rear wheel traction.

[Brief explanation of the drawing]

1 and 2 are conceptual diagrams of a motorcycle and its main parts for defining various quantities, FIGS. 3 to 10 show examples, and FIG. 3 is a configuration diagram of a control system, Figure 4 is a cross-sectional view showing the driving force sensor, Figure 5 is a conceptual diagram for calculating driving force, Figure 6 is a conceptual diagram of the rear arm, Figure 7 is a conceptual diagram of the stroke sensor, and Figure 8 is a block diagram. FIG. 9 is a graph showing the relationship between the rear axle stroke and the scot ratio, anti-scort ratio, etc., and FIG. 10 is a graph showing the relationship between the rear axle stroke and the damping force. (Explanation of symbols) F...Driving force, ψ...Rear arm angle, ΔF...
Additional reaction force converted to rear axle, Δf...Additional reaction force, 1.
... Rear wheel, 3... Rear arm, 4... Rear axle, 5... Rear suspension, 7... Front suspension, 8... Damper, 20... Control circuit, 2
4... Driving force sensor, 25... Rear arm angle sensor, 26... Front stroke sensor. Patent applicant: Agent for Honda Motor Co., Ltd.
Patent Attorney Kiyoshi Komatsu Mitsu Daiko I4 Figure Figure Figure Figure

Claims (1)

[Claims] A damper with variable damping force, a driving force sensor for detecting driving force or braking force, a front stroke sensor for detecting the stroke amount of the front suspension, and a rear arm for detecting the angle of the rear arm with the horizontal line. The angle sensor and the difference between the skort force and the anti-skort force determined by geometric calculation based on the detection signals of these sensors are determined, the amount of change in damping force is determined based on this difference, and the amount of change in damping force is determined based on this difference. A variable rear suspension device comprising: a control circuit that outputs a control signal for adjusting the damping force of the damper based on the damping force of the damper.