JPH02189295A - Motorcycle - Google Patents

Abstract

PURPOSE:To make both wobble prevention and rear-wheel steerage performable by intersecting a straight line, connecting vertical connecting points of a knuckle to an arm member, with a perpendicular passing through a rear-wheel grounding point, installing a caster angle therein, and controlling the damping force of a hydraulic damper being installed between the knuckle and the arm member. CONSTITUTION:A knuckle 41 is bendably connected to an arm member 21 at two vertical points A, B passing through a drive shaft center O. Then, a straight line K connecting these two points A, B is intersected with a perpendicular L passing though a ground point S of a rear-wheel tire 16t and a caster angle alpha is installed in a rear wheel 16. In succession, damping force in a hydraulic damper 51 being installed between a ball joint 48 at a tip of a knuckle arm 43 and a knuckle arm holder 27 is varied by a control unit 64 in accordance with the specified procedures via a variable throttle valve 61. With this constitution, any wobble can be prevented from occurring and, what is more, rear-wheel steerage is made possible.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention enables the rear wheels to be steered by a lateral force acting on the tire grounding point without providing a steering device on the rear wheel side, and also according to the driving conditions. The present invention relates to a motorcycle that allows rear wheel steering to be permitted or restricted depending on the circumstances.

[Prior Art] A motorcycle in which one end side of a drive shaft of a rear wheel is supported with respect to a rear fork via an elastic device is known from Japanese Patent Laid-Open No. 70277/1989 proposed by the present applicant. . According to this, it is possible to absorb and alleviate the horizontal vibrations of the rear wheels that are experienced during high-speed driving, and it is possible to prevent the occurrence of wobble (high-frequency vibration around the steering shaft) without affecting the dynamic characteristics of the tire.

Furthermore, a motorcycle equipped with a steering device connected from a bar handle to the rear wheel side is also known from Japanese Patent Application Laid-Open No. 62-71780, which enables steering of the front and rear wheels and improves turning performance.

[Problems to be Solved by the Invention] Incidentally, the latter requires a rear wheel steering device that is linked in addition to the usual front wheel steering device.

Also, unlike four-wheeled vehicles such as passenger cars, motorcycles use a steering operation by banking the vehicle body to one side when cornering or changing lanes, so only a small amount of steering angle is required for the rear wheels. .

On the other hand, although the former method can prevent the occurrence of wobble, it does not allow rear wheel steering to follow steering.

Therefore, in addition to being able to prevent the occurrence of wobble, it is an object of the present invention to create a trail by providing a caster angle on the rear wheel without providing a steering device on the rear wheel side, thereby reducing the lateral force acting on the tire grounding point. In addition to allowing rear wheel steering using the The object of the present invention is to provide a motorcycle in which rear wheel steering can be regulated.

[Means for Solving the Problems] In order to achieve the above problems, the present invention provides an arm member 21 extending rearward from the body of a motorcycle, a drive shaft 31 rotatably supported by the arm member 21, and the drive shaft. Rear wheel hub 38 bendably connected to 31
, the arm member 2 rotatably supports this rear wheel hub 38.
Two points A above and below passing through the drive shaft center O for the 1 side,
The knuckle 41 is connected to the arm member 21 side in a side view so that the knuckle 41 can be bent, and the line segment K connecting the upper and lower connection points A and B of the knuckle 41 with respect to the arm member 21 side is connected vertically to the grounding point S of the rear tire 16t. A hydraulic damper 51 that intersects with the line and provides a caster angle α on the rear wheel 16, and is installed between the knuckle 41 and the arm member 21 side, and a variable throttle valve that changes the damping force of the hydraulic damper 51. 61,
The present invention is characterized in that it includes an actuator 63 that drives the variable throttle valve 61 and a control device 64 that operates the actuator 63.

Specifically, the control device 64 operates the actuator 63 to drive the variable throttle valve 61 based on the vehicle speed V, the bank angle θBANK at which the vehicle body tilts laterally, or the amount of depression of the vehicle body, and the hydraulic damper 51 change the damping force of

Then, the vehicle speed V and the front wheel steering angle θ are detected, the turning radius R is calculated from the data map, and the bank angle θ[lAN is determined.

Alternatively, calculate the amount of sinking from the longitudinal acceleration (vertical G).

[Function] A knuckle 41 bendably connects a rear wheel hub 38 to a drive shaft 31 rotatably supported by an arm member 21 extending rearward from the motorcycle body, and rotatably supports the rear wheel hub 38. is bendably connected to the arm member 21 side at two upper and lower points A and B that pass through the drive shaft center O. The rear wheels 16 can be steered by using the line segment as steering IthK.

Furthermore, by installing a fluid pressure damper 51 between the knuckle 41 and the arm member 21 side, the damping force generated by the throttle valve 61 of this fluid pressure damper 51 can provide resistance to the steering behavior of the rear wheel 16. In addition, the amount of steering can be regulated, and horizontal vibrations of the rear wheels 16 that are received during high-speed driving can be absorbed and alleviated, thereby preventing the occurrence of a crash.

Since the rear wheel 16 is provided with a caster angle α by making the steering axis K intersect with a vertical line passing through the grounding point S of the rear tire 16t in a side view, the rear wheel 16
A trail 1 is generated, and therefore, the rear wheels 16 are steered around the steering axis by the lateral force F acting on the tire grounding point S by the steering operation of the vehicle body.

In the above, the fluid pressure damper 51 is provided with the variable throttle valve 61, and is equipped with its actuator 63 and control device 64.

For example, the control device 64 determines the vehicle speed V and the bank angle θBANK at which the vehicle body leans to the side (determined by detecting the vehicle speed V and front wheel steering angle θ, and calculating the turning radius R from the data map) or the amount of sinking of the vehicle body (vertical G actuator 63 to drive variable throttle valve 61 based on
The damping force of the fluid pressure damper 51 is changed.

By controlling the damping force, it is possible to allow the rear wheels to be steered, for example, during straight running or steady turning when the vibration of the front wheel steering angle θ is large.In other words, by lowering the damping force, the rear wheels can be steered freely, thereby improving stability. In addition, rear wheel steering can be restricted when turning or changing lanes when vibrations in the front wheel steering angle θ are small.In other words, by increasing the damping force and fixing the rear wheels in a neutral steering state, maneuverability can be improved. You can improve.

[Example] Examples will be described below based on the accompanying drawings.

FIG. 1 shows a motorcycle as an example to which the present invention is applied, and the illustration shows a body frame 2 on which an engine 1 is mounted.
An upper body 3 is connected to the upper part of the body 3. A seat 4 is installed on the upper part of the body 3, and a bar handle 5 is provided on the front part. The front wheel 6 has a shaft 7 supported on a cantilever by a knuckle 8, and a steering link mechanism 9 is installed from the bar handle 5 to the knuckle 8. It is supported by arm 11.

The swing arm 11 is composed of an upper arm 12 and a lower arm 13 arranged at the top and bottom, and a shock absorber 14 and a productive link mechanism 15 are installed between the swing arm 11 and the front part of the vehicle body frame 2.

Trailing type rear swing arms 21 are pivotally supported on the left and right sides of the rear part of the vehicle body frame 2 to support the rear wheels 16. and a progressive link mechanism 18 are installed.

In the above, the support structure for the rear swing arm 21 of the rear vM16 is as shown in FIGS. 2 to 4.

That is, a bearing block 25 is integrally assembled into the rear part 24 of the rear swing arm 21 from the rear and from the top and bottom, as shown in the figure, and is connected by a large number of bolts and nuts. A book knuckle holder 26, 26 and a knuckle arm holder 27 extending forward are integrated.

The drive shaft 31 is divided into a left shaft 32 and a right shaft 33, and the left end of the right shaft 33 is located within the right end of the left shaft 32 and has an arcuate spline fitting portion 34.
are connected so that they can be bent slightly.

The right half of the left shaft 32 of this drive shaft 31 is rotatably incorporated into the bearing block 25 via the left two rows of ball bearings 35 and the right roller bearing 36, and the right end of the right shaft 33 is provided with a rotational force. A rear wheel hub 38 is connected via a constant velocity ball joint 37 that can be bent while transmitting the same. As shown in the figure, the wheel 16''W of the rear wheel 16 and the brake disc 39 are connected to the right end of the rear wheel hub 38 by a plurality of bolts and nuts.

Here, the rear swing arm 21 is formed by bending the middle part to the left, and the wheel 16w of the rear wheel 16 is also formed by displacing the outer peripheral part to the left, and the wheel rim 16r faces inside the middle part of the rear swing arm 21. I'm here.

A knuckle 41 rotatably supports the rear wheel hub 38.
is provided. The knuckle 41 has upper and lower protrusions 42, 42.
and one knuckle arm 43 extending forward are integrally provided, and this knuckle 41 is assembled onto the rear wheel hub 38 via two rows of ball bearings 44.

Ball joints 45.45 are incorporated into the upper and lower protrusions 42, 42 of this knuckle 41, and the horizontal screw members 46.46 are connected to the knuckle holder 26.
．． It is screwed and connected to 28. These upper and lower ball joints 45.45 allow the knuckle 41 to bend relative to the knuckle holder 26.26 on the rear swing arm 21 side.

As shown in FIG. 2, when viewed from the side, the line segment connecting the centers A and B of the upper and lower ball joints 45 and 45 passes through the drive shaft center O. In addition, as shown in FIG. 3, the constant velocity ball joint 3 is aligned above the line segment when viewed from the rear.
7 and the ball bearing 44 are arranged, and the line segment coincides with the center line C of the wheel rim 16'' of the rear wheel 16, as shown in FIG.

Further, a ball joint 48 is connected to the front end of the knuckle arm 43 by screwing a vertical screw member 47 thereinto, and a fluid pressure damper 51 is installed between the ball case 49 and the knuckle arm holder 27 as shown in FIG. It is constructed like this.

The fluid pressure damper 51 has an oil chamber 5252 that is partitioned left and right by a piston 55 provided in the inner cylinder 54 and formed between the outer cylinder 28 at the front end of the knuckle arm holder 27.
is adapted to slide in an oil-tight manner between the inner wall 29 at the right end of the outer cylinder 28 and a nut member 56 screwed into the left end.

The left half of the screw member 57 is inserted into the inner cylinder 54, and the inner cylinder 54 is interposed between the flange 58 and the nut 59, and the right side of the screw member 57 is screwed and connected to the ball case 49. There is.

In the above fluid pressure damper 51, the left and right oil chambers 52.5
An oil passage 53 is provided that externally connects the two, and a variable throttle valve 61 and an accumulator 62 are installed in this oil passage 53. The variable throttle valve 61 is driven by a motor actuator 63 using a servo motor.
The operation of this motor actuator 63 is controlled by a control unit (control device) 64 as described later. The variable throttle valve 61, the accumulator 62, the motor actuator 63, and the control unit 64 are arranged at appropriate locations on the vehicle body.

Here, the left shaft 32 of the drive shaft 31
A driven sprocket 72 is installed on the left half of the engine 1 via a damper device 71, and a chain 73 is hung between the drive sprocket provided on the output shaft (not shown) of the engine 1 and the driven sprocket 72. Further, a rear brake caliper 79 is installed at the rear of the knuckle 41 to apply braking force to the brake disc 39.

In a motorcycle with the above rear wheel support structure, the second
As shown in FIG. 5, the upper and lower ball joints 45.4 connect the protrusion 42.42 of the knuckle 41 to the knuckle holder 26.26 on the rear swing arm 21 side.
A line segment K connecting the center points A and B of 5 is intersected in side view with a vertical line passing through the grounding point S of the rear tire 16t.
A caster angle α is provided at 6.

In this embodiment, the line segment K is set to be tilted forward as shown in the figure, and the intersection point T with the ground is placed behind the tire contact point S, so that a negative trail 1 is generated on the rear wheel 16. ing.

Next, rear wheel steering will be explained.

First, the rear wheels 16 can be steered around the line segment, and therefore the line segment is a steering axis.

For example, when the vehicle starts to turn left after traveling straight, a lateral force (centripetal force) F is applied to the tire grounding point S from the right side as shown in FIG. Then, the vehicle is steered backward from the tire contact point S.
Since the intersection point T with the ground is located, a moment of point 7g is generated due to the lateral force F acting on the tire contact point S as shown in Fig. 7, and the rear wheel 16 rotates to the left in the same direction as the turning direction. be steered.

When the rear wheel 16 turns around the steering axis, the steering behavior of the rear wheel 16 is controlled by the damping force generated by the throttle valve 61 of the fluid pressure damper 51 installed between the knuckle arm 43 and its holder 27. The amount of steering is regulated. In addition, the hydraulic damper 5 absorbs the horizontal vibration of the rear wheel 16 that is received when driving straight at high speed.
Since the absorption is relaxed by 1, the generation of opple is also prevented.

In this way, by setting the rear wheels 16 to be steered in the same direction as the turning direction by the lateral force generated when the vehicle turns,
Not only does it provide agile maneuverability, it also generates a large amount of cornering power from the tires, increasing turning power.

Here, since it is a motorcycle, it is preferable that the rear wheel steering angle is within a range of about 0.5° at the maximum.

It should be noted that the rear swing arm 21 may be constructed of three parallel links, upper and lower, and if it is of the parallel link type, the rear wheel caster angle α can be kept constant.

Next, damping force control of the fluid pressure damper 51 will be explained.

First, as shown in FIG. 8, a vehicle speed sensor 65 that detects the vehicle speed V based on a speedometer or the like, and a steering angle sensor 66 that detects the front wheel steering angle θ based on the steering angle of the steering wheel 5 are provided.
The control unit 64 performs arithmetic processing and map processing on the detection signals from both sensors 65 and 66, and outputs a control signal to the motor actuator 63.

Here, the purpose of detecting the vehicle speed ■ and the steering angle (front wheel steering angle) θ is to calculate the turning radius R, and the bank angle θBANK at which the vehicle body leans to the side has the following relationship: -R taneBANK=■2 This is because the bank angle θBANK is inversely proportional to the square of the speed V and proportional to the turning radius R.

FIG. 9 shows a first embodiment of control, and briefly explains:
Read θ and ■, and calculate R from the data map of θ, v, and R. The map is shown in Figure 10, R=f(θ,
v).

Then, a set value RstT=f (V), which is a control threshold for the turning radius based on (2), is calculated (see FIG. 11), and R and R5E are compared. The time when R5ET≦R is considered to be the start of cornering, and when Rx>R, the time is considered to be straight ahead and steady turning, which is not cornering.

R8! If T≦R, input 1 to the corner song flag and CF through the timer to indicate cornering, output a control signal to the actuator 63, set the control time Tc, and return to the original loop. repeat. This time Tc is compared by the timer, and again the time Tc
After the elapsed time, similar processing is performed, and if Tc does not elapse, the process returns to the original state.

Also, if R9ET>R, cornering flag; CF
0 indicating that it is not cornering is input to , a control signal is output to the actuator 63, and the loop is repeated.

Through the above processing, the bank angle θBA? Performs variable control of damping force based on lK.

That is, during straight travel and steady turning, the opening degree of the variable throttle valve 61 of the fluid pressure damper 51 is increased to fully open, etc. to reduce the generated damping force, and the rear wheels 16 can be steered freely to improve stability. . Further, when turning back or changing lanes, the variable throttle valve 61 is closed to fix the movement of the rear @16 in the steering direction to the neutral position, improving maneuverability.

Next, control of the second embodiment will be explained.

First, in FIG. 8, a vehicle body longitudinal acceleration (vertical G) sensor 67 is provided in place of the steering wheel angle sensor. This vertical G sensor 67 is attached under the spring of the suspension,
The amount of depression of the vehicle body during turning is detected from the detected vertical G.

To briefly explain the control shown in FIG. 13, V.

Read ljG and select R from the data map of ■, vertical G, and R.
is calculated, and the difference ΔR between the previous R and the current R is calculated from (■). Mo and vertical G from the previous R3, A and this R3ET
The difference ΔR5E is calculated, and ΔR and ΔR5ET are compared. Here, ΔR3I! ? The time when ≦ΔR is determined to be the start of cornering, and when ΔR8ε>ΔR, the vehicle is considered to be traveling straight and making a steady turn without cornering.

Next, if ΔR3ET≦ΔR, the flag CF is set to 1 via a timer, a control signal is output to the actuator 63, the control time Tc is set, and the loop is repeated. Tc is compared by the timer, and the same process is performed again after Tc has elapsed, and if Tc has not elapsed, the process returns to the original state. In addition, if ΔR3ET>ΔR, the flag; CF is set to 0, and a control signal is output to the actuator 63.
Go back and repeat the loop.

Through the above processing, variable control of the damping force is performed based on the change in longitudinal G (turnback and lane change) and the magnitude of longitudinal G (during straight travel and steady turning) as shown in FIG. 14 in response to vehicle speed V.

In the above two-side control, the actuator 63 using a servomotor has been described, but an actuator using an ON10FF type solenoid may be used as long as the damping force is switched in two stages between high and low levels.

Next, control of the third embodiment will be explained.

In this embodiment, as in the first embodiment, a vehicle speed sensor 65 and a steering angle sensor 66 are provided as shown in FIG.

To briefly explain the control shown in Fig. 15, θV is read and R is calculated from the map of θ, v, and R (see Fig. 10).
R=f(θ,■)). Next, calculate the bank angle θIIANX=K·−v2 from v and R, where K: constant.

Then, the damping force is calculated from the map of V, θIIANK, and damping force shown in FIG. 16, and a control signal is output to the actuator 63, and the operation of the actuator 63 is feedback-controlled.

In this way, the driving conditions are set using the vehicle speed ■ and the bank angle θ13ANK, and the damping force of the fluid pressure damper 51 is made to respond to the frequency of the front wheel steering angle, thereby achieving both improved stability and improved maneuverability. It is.

In other words, as shown in Figure 16, low speed range (for example 0 to 40 km/h)
), the damping force is II regardless of the bank angle θ13ANK.
, and in the medium speed range (41 to 120 km/h), the damping force is changed from
In the high speed range (121 km/h=MAX), the damping force is set in the entire range from II to MID and further to LOW depending on the increase in the bank angle θRAN.

In this way, especially at high speeds, when the bank angle θ8A□ becomes a dog and the vibration of the front wheel steering angle is large, the damping force is lowered and the rear wheel 16
This improves stability by allowing the vehicle to steer freely. Also, when the bank angle θRAN is very small in each vehicle speed range, or when the vibration is small such as when the bank angle θBANK is large but at low speeds, the variable throttle valve 61 is closed to control the movement of the rear wheels 16 in the steering direction. Fixed in neutral position to improve maneuverability.

Here, in the map of FIG. 16, the damping force was made to change continuously over the entire range from HI to LOW by the servo motor actuator 63, but i
It may be changed in three steps: ll, MJD, and LOW.

It goes without saying that any body structure, front wheel suspension system, and steering system may be used for the motorcycle. Furthermore, appropriate joints may be used.

[Effects of the Invention] As described above, according to the motorcycle of the present invention, the steering axis is the line segment connecting the two upper and lower connection points of the knuckle to the arm member side without providing a steering device on the rear wheel side. It is possible to steer the rear wheels, and the damping force generated by the hydraulic damper installed between the knuckle and the arm member side can provide resistance to the steering behavior of the rear wheels, and the amount of steering can be regulated. It also absorbs and alleviates the horizontal vibrations that the rear wheels experience when driving at high speeds, preventing wobble. Since the angle is provided, a trail is generated on the rear wheels, and therefore, the rear wheels can be steered around the steering axis by the lateral force acting on the tire grounding point by steering operation of the vehicle body.

Since the fluid pressure damper is equipped with a variable throttle valve and its actuator and control device, the control device operates the actuator to drive the variable throttle valve based on, for example, the vehicle speed and bank angle or the amount of depression of the vehicle body. By changing the damping force of the fluid pressure damper, rear wheel steering can be allowed, for example, during straight travel and steady turns where vibrations in the front wheel steering angle are large.In other words, by lowering the damping force, the rear wheels can be steered freely. In addition, when turning or changing lanes when front wheel steering angle vibration is small, rear wheel steering can be controlled by increasing the damping force and steering the rear wheels. Maneuverability can be improved by fixing it in a neutral state. In this way, both improved stability and improved maneuverability can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view of a motorcycle as an example to which the present invention is applied, Fig. 2 is an enlarged side view showing the area around the rear wheel support part, Fig. 3 is a longitudinal cross-sectional view of the motorcycle as seen from the rear, Figure 4 is a cross-sectional view seen from above, Figure 5 is a schematic side view showing the relationship between caster angle and trail, Figures 6 and 7 are schematic plan views explaining rear wheel steering behavior, and Figure 8. 9 is a control block diagram, FIG. 9 is a flowchart according to the first embodiment of control, and FIG. 10 is a control block diagram.
The figure is a map of θ, v, and R, Figure 11 is a map of "+R8ET," Figure 12 is a characteristic diagram of damping force for θaAN, and Figure 1 is a map of θaAN and damping force.
3 is a flowchart according to the second embodiment of control, the 14th
The figure is a characteristic diagram of longitudinal G change, longitudinal G magnitude and damping force, 1st
5 is a flowchart according to the third embodiment of control, the 16th
The figure is a characteristic diagram of V and θ[1ANK and damping force. In addition, in the drawing, IS is a rear wheel, 21 is an arm member, 26 is a knuckle holder, 27 is a knuckle arm holder 31
is a drive shaft, 37 is a constant velocity joyseat, 38 is a rear wheel hub, 41 is a knuckle, 43 is a knuckle arm, 45
．． 48 is a ball joint, 51 is a fluid pressure damper, 52
53 is an oil chamber, 53 is an oil path, 61 is a variable throttle valve, 62 is an accumulator, 63 is an actuator, 64 is a control device, 6
5 is a vehicle speed sensor, 66 is a steering wheel angle sensor, 67 is a vertical G sensor, A and B are connection points, F is a lateral force, K is a steering axis, L
is the vertical line, 0 is the center of the drive shaft, S is the tire grounding point, α is the caster angle, and °C is the trail. Figure 8 Figure 9 Figure 13 Figure 15

Claims (1)

[Scope of Claims] 1. An arm member extending rearward from the vehicle body, a drive shaft rotatably supported by the arm member, a rear wheel hub bendably connected to the drive shaft, and the rear wheel hub rotatable. The knuckle is supported on the arm member side and is bendably connected to the arm member side at two points above and below that pass through the center of the drive shaft, and when viewed from the side, the line connecting the two upper and lower connection points of the knuckle with respect to the arm member side is the rear wheel. A caster angle is provided on the rear wheel to intersect with a vertical line passing through the grounding point of the tire, and a hydraulic damper is installed between the knuckle and the arm member side.
A motorcycle comprising: a variable throttle valve that changes the damping force of the fluid pressure damper; an actuator that drives the variable throttle valve; and a control device that operates the actuator. 2. The control device according to claim 1, wherein the control device operates the actuator to drive the variable throttle valve based on the vehicle speed and the bank angle at which the vehicle body tilts laterally, and changes the damping force of the fluid pressure damper. Motorcycle. 3. The motorcycle according to claim 2, wherein the bank angle is determined by detecting a vehicle speed and a front wheel steering angle, and calculating a turning radius from a data map. 4. The motorcycle according to claim 1, wherein the control device operates the actuator to drive the variable throttle valve based on the vehicle speed and the amount of depression of the vehicle body, and changes the damping force of the fluid pressure damper. 5. The motorcycle according to claim 4, wherein the amount of depression is determined from longitudinal acceleration.