JPH0214972A - Steering gear for vehicle - Google Patents

Abstract

PURPOSE:To increase the degree of control setting freedom of a power assist for a bar handle having a small steering angle by permitting an actuator for the power assist to be variably controlled on the basis of the torsional phase difference generated on a steering shaft. CONSTITUTION:When a bar handle is turned right, an inner shaft 22 is twisted according to a steering force, an outer shaft 21 coupled with a steering shaft end 25 is first rotated clockwise by the torsional amount of said shaft 22 and a spool rod 34 integral with the outer shaft 21 is moved backward. A torsion is generated in the inner shaft 22 integral with the shaft end 25 to allow the inner shaft 22 to function as a torsion bar. Thus, a steering force corresponding to the torsion of the inner shaft 22 is transmitted to the shaft end 25 and an actuator body 30.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a steering device for a vehicle that includes a power steering device and a bar handle.

[Prior Art] There is a bar handle type vehicle equipped with a power steering device, which is known, for example, from Japanese Patent Laid-Open No. 62-46787.

[Problems to be Solved by the Invention] However, in the past, the structure for controlling the rotation angle of the steering wheel was complicated, and a power steering device for a bar handle type vehicle has a simple structure and is advantageous in terms of cost. The realization of a control device is desired.

Therefore, an object of the present invention is to generate a torsional phase difference in a steering shaft, detect the phase difference, and make the transmission force of a power assist actuator variable, thereby simplifying the structure and being advantageous in terms of cost. An object of the present invention is to provide a vehicle steering device that increases the degree of freedom in setting power assist control for a bar handle with a small steering angle.

[Means for Solving the Problems] In order to achieve the above-mentioned problems, the present invention provides an upper steering shaft that rotates together with a bar handle, a lower steering shaft that has an attachment part for a link mechanism connected to a steering wheel. , a torsional phase difference generating section disposed between the lower steering shaft and the upper steering shaft;
A phase difference detection section that detects the relative displacement of the torsional phase difference generation section and an actuator that power assists the lower steering shaft in conjunction with the phase difference detection section are provided, and the transmission force of the actuator is transmitted to the steering shaft. It is characterized by being variable by changing the arm ratio of the arms that rotate together around the axis.

Specifically, the phase difference detection section is an arm disposed on the upper steering shaft, one end of a control section that controls the actuator is connected to the arm, and the other end of the control section is swingably attached to the vehicle body. It is installed.

Further, an arm is disposed on the lower steering shaft, one end of an actuator is connected to the arm, and the other end of the actuator is swingably attached to the vehicle body.

[Function] A torsional phase difference is generated between the upper steering shaft and the lower steering shaft by the steering operation of the bar handle, and based on the detection of the relative displacement, the transmission force of the actuator becomes variable by changing the arm ratio of the arm.
The actuation of the actuator provides power assistance to the lower steering shaft, ie, reduces the steering force.

Although the structure is simple and advantageous from a cost standpoint, it is possible to variably control the operation of the power assist actuator by changing the arm ratio of the arm based on the torsional phase difference generated in the steering shaft. By changing the degree of occurrence of phase difference and the swing radius of the arm, the degree of freedom in setting the power assist control for a bar handle with a small steering angle can be increased.

The phase difference detection section is an arm disposed on the upper steering shaft, one end of the control section that controls the actuator operation is connected to the arm, and the other end of the control section is swingably attached to the vehicle body. By disposing an arm on the steering shaft, connecting one end of the actuator to the arm, and attaching the other end of the actuator to the vehicle body in a swingable manner, as the steering angle of the bar handle increases, the lower steering shaft is moved by the actuator. The assist force or operating ratio of the control unit becomes smaller.

As a result, in the work assist range of the bar handle,
As the steering angle increases from the neutral steering position, a larger steering force is required, so in the small steering angle range, which is the range used during normal driving, the bar handle can be operated with a light steering force, while at low speeds the bar handle can be operated with a large steering angle. In the range, the steering force can be increased to help prevent the steering wheel from turning too sharply.

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

In FIG. 1 showing the external appearance of a straddle-type four-wheeled vehicle to which the present invention is applied, the left and right front wheels 2 and rear wheels 3 equipped with low-pressure tires at the front and rear of a vehicle body in which an engine 1 is mounted in the center are shown in FIG. Engine power is transmitted to front wheels 2 and rear wheels 3, 4 is a front fender, 5 is a seat, and 6 is a rear fender. 4. Operate the bar handle 7 located above. The bar handle 7 is fixed to the upper end of the steering shaft 20 as shown in the figure, and the actuator body 30 is connected to the lower end of the steering shaft 20, and supports the steering arm 29 fixed to the lower end of the steering shaft 20 and the front wheels 2 forming steering wheels. Tie rods 9 are installed between the knuckle arms 8, respectively.

In this way, it is a straddle-type four-wheeled vehicle equipped with a bar handle 7, and the transmission is from the steering shaft 20 to the tie rod 9 and knuckle arm 8, which form a steering link mechanism, or the steering arm 29, resulting in large diameter tires or wide tires. Because it requires such a large steering force, it is equipped with a hydraulic power steering device.

As shown in FIGS. 3 and 4, the front part of the vehicle body frame 10 includes a main vibe 11, an under vibe 12, a front vibe 13. It is composed of a front cushion vibe 14 and a steering underhold vibe 15, and an actuator body 30 is disposed within the front space of this frame 11. The steering shaft 20 has an upper part supported by a holder 18 on the front end of the main vibe 11, and a lower part supported by a bracket 19 installed between the steering under-hold vibes 15, and an actuator body 30 on the right side extending from the steering under-hold vibe 15 at the rear. is pivotally supported on the vibrator end 16 via a vertical shaft 17.

The hydraulic power steering device includes a control valve section V, a power assist cylinder section S, an oil reservoir tank T, an oil pump P, etc. built into the actuator body 30. The reservoir tank T is fixed between the upper part of the front pipe 13, and the oil pump P is fixed to the cylinder head 1a of the engine 1 and is driven integrally with the camshaft lb or via a joint (not shown). is connected with the old suction hose, and the oil pump P
and the actuator body 30 are connected by a foot hose H2, and the actuator body 30 and the reservoir tank T are connected by a return hose H3.

By the way, the steering shaft 20 consists of an outer shaft 21, an inner shaft 22, and a shaft end 25, as shown in FIG. The steering bridge 23 is connected to the steering bridge 23, which is fixed to the steering bridge 23. Then, the upper end of the shaft end 25 is inserted into the lower end of the inner shaft 22 and fixed by the welding joint 26, and the lower inner circumference of the outer shaft 21 forming the upper steering shaft and the upper outer circumference of the shaft end 25 forming the lower steering shaft are approximately As shown in FIG. 6(b), they are connected to each other by a spline fitting portion 27 with a predetermined gap C, C provided on both sides in the rotational direction. A bearing 28 is interposed between the upper and lower parts of the spline fitting part 27 which forms the torsional phase difference generating part of the inner shaft 22 through the gaps C and C, and a steering arm 29 is fixedly installed at the lower end of the shaft end 25. .

The actuator body 30 is shown in FIGS. 6(a) and (
C) and as shown enlarged in FIG. 7 and subsequent figures. The actuator body 30 is formed by bolting a valve body 31 onto a cylinder body 41, and a valve hole 32 provided in the valve body 31 and opening at the front and a cylinder 42 provided in the cylinder body 41 and opening at the rear are vertically parallel to each other. .

A spool rod 34 is pivotally connected to the forward protruding part of a spool valve 33 installed in the valve hole 32 by a vertical pin 35, and the front part of the rod 44 of a piston 43 installed in the cylinder 42 via a seal projects forward. It faces into the slot hole 45 at the front of the cylinder body 41. A boot 36 is provided between the valve body 31 and the spool rod 34, a check valve 37 is built into the upper part of the valve body 31, and joints 38 and 39 for connecting the hoses H2 and H:1 are provided on the upper surface. ing. The rear part of the piston rod 44 is sealed to the cylinder 42 by a rod guide 46, etc., and a rod end 47 provided at the rear protrusion is pivotally supported on the vertical shaft 17 via a collared rubber bushing 48. A boot 49 is provided between 47.

And the outer shaft 2 of the steering shaft 20
A first arm 72 forming a phase difference detection section is bolted to the stayer 1 which is fixed by welding or the like on the outer periphery of the lower part of the stayer 1, and this first arm 72 protrudes to the right and has a spool rod 3 at its right end.
4 front ends are pivotally connected by a vertical pin 73. Further, a second arm 75 is fixed by welding to the outer periphery of the middle part of the shaft end 25 at the lower part of the steering shaft 20, and this second arm 75 also protrudes to the right and is connected to the front end of the cylinder body 41 by a vertical bolt 76 at its right end via a bearing 77. The parts are pivotally connected. In the embodiment, when the vehicle is traveling straight, the vertical pin 73 and the vertical bolt 76 align on the same axis.

As described above, the power assist cylinder section S functions as an actuator, and the control section that controls its operation is a spool type control valve section V.

Next, the operation will be explained.

The oil discharged from the oil pump P passes through the foot hose ■2, passes through the spool valve 33 in the actuator body 30, and is returned to the reservoir tank T from the return hose H3. The oil is circulated through the oil pump P.

A check valve 37 is installed in the bypass oil passage 58 between the inlet oil passage 51 and the return oil passage 59 provided in the actuator body 30, and allows flow only from the return oil passage 59 to the inlet oil passage 51. When the pump is stopped, the actuator body Oil circulation takes place within 30.

When driving straight without turning the par handle 7, the oil flowing into the valve hole 32 from the oil passage 51 as shown by the arrow in FIG. Front and rear oil passages 55, 52 provided
The oil is distributed to the front and rear lands 82, 64 through the oil holes 63 and 65, passes through the spool central oil passage 66, and is returned to the reservoir tank T through the return oil passage 59.

When the bar handle 7 is turned to the right, the inner shaft 22 is twisted according to the steering force, and the steering shaft end 25
As shown in FIG. 6(b), the outer shaft 21 connected by the spline fitting portion 27 with a gap C is first rotated clockwise as indicated by the arrow in FIG. 6(a) by the amount of twist.
The inner shaft 2 is integral with the shaft end 25, and the spool rod 34, which is pivotally connected to the first arm 72 which is integral with the outer shaft 21, moves rearward as shown in FIG.
In other words, the inner shaft 22 functions as a torsion bar having a phase difference that lags behind the rotation of the outer shaft 21. Therefore, the steering force due to the torsion of the inner shaft 22 is transmitted to the shaft end 25, and the steering force due to the torsion of the inner shaft is also transmitted from the second arm 75 integrated with the shaft end 25 to the actuator body 30. In this way, at the beginning of steering, the first arm 72 on the input side rotates about the steering shaft center with a certain phase difference from the second arm 75 on the output side.

Then, the phase difference between the steering outer shaft 21 and the steering inner shaft 22 is amplified by the swing radius of the first arm 72, and the spool valve 3 is moved from the spool rod 34 to the spool valve 3.
3. By operating this spool valve 33, the oil flow changes as shown in FIG.

That is, when the spool valve 33 moves backward, the oil enters as shown by the arrow and flows through the oil passage 51, the central land 61, and the oil passage 52.
From there, it is fed into the rear hydraulic chamber of the cylinder 42 via oil passages 53 and 54 in the cylinder body 41. Further, the oil in the front hydraulic chamber of the cylinder 42 flows from the oil passage 56 in the cylinder body 41 to the front runt 62 via the oil passage 55, and the oil in the rod hole 45 also flows from the oil passage 57 in the cylinder body 41 to the front runt 62. It flows into the runt 62 , the oil hole 63 , the oil path 66 , and the return oil path 59 .

The piston 43 moves forward inside the cylinder 42 due to the pressure of the oil sent to the rear hydraulic chamber of the cylinder 42 in this way, but since the piston rod 44 is supported by the vehicle body by the rod end 47, the actuator body 30 will move backwards. When the actuator body 30 moves backward, force is transmitted to the integrated steering shaft end 25 via the second arm 75 pivotally connected to the front part of the actuator body 30, and by rotating the steering shaft end 25 with hydraulic pressure, the steering force is generated. is reduced.

In this case, the piston rod end 47 is pivotally supported via the rubber bush 48 to the vehicle body frame lO (right steering under hold pipe end 16) so as to be able to swing around the vertical axis 17.
The left and right rocking of the actuator body 30 due to the rotation of the second arm 75 and the second arm 75 is absorbed.

Further, when the input from the bar handle 7 exceeds the gap C, the steering force is directly transmitted from the spline fitting portion 27 to the steering shaft end 25.

When the bar handle 7 is turned to the left, the first arm 72 and the spool rod rotate from the outer shaft 21, which rotates counterclockwise as shown by the arrow in FIG. 34, the spool valve 33 moves forward as shown in FIG. The steering force due to the torsion of the inner shaft 22, which functions as a torsion bar with a phase difference that lags behind the rotation of the outer shaft 21, is transmitted to the shaft end 25, the second arm 75, and the actuator body 30. The arm 72 rotates around the steering shaft center with a certain phase difference from the output side second arm 75.

By moving the spool valve 33 backward, oil enters as shown by the arrow in the oil passage 51 and the central land 61° oil passages 55 and 56.
The oil is sent from the cylinder 42 to the front hydraulic chamber. Also, the oil in the rear hydraulic chamber of the cylinder 42 flows through oil passages 54, 53, 52.
．． Flows into the oil passage 66 from the rear land 64 and the oil hole 65,
Here, the oil hole 63 and the front land 62 are divided into the front and rear.
and flows into the rod hole 45 from the oil passage 57,
The oil flows from the oil passage 66 to the return oil passage 59.

The piston 43 moves backward in the cylinder 42 due to the pressure of the oil sent into the front hydraulic chamber of the cylinder 42, which means that the actuator body 30 moves forward and force is transmitted from the second arm 75 to the steering shaft end 25. .

In the above, the pivot connection point between the second arm 75 and the actuator (power assist cylinder part S) is rotated in a circle from the neutral steering position N to the left and right maximum steering positions a and b by the steering angle of the bar handle 7, as shown in FIG. 1O. A trajectory that moves in an arc (
Draw an arc locus centered on the 0 point of the steering shaft center.

Therefore, the center line of the actuator swings around the fulcrum P from the neutral position Cn, and the direction changes (see Ca and Cb). Therefore, the power assist force Fa of the actuator acts on the steering shaft only by the component force Fs relative to the moment of the steering force, and the power assist force is FS-R.
Therefore, the force Fa−R is smaller than the force Fa−R near the steering neutral position N. In other words, the power assist force decreases as the steering angle increases from the vicinity of straight-ahead travel.

In addition, in Fig. 10, as can be seen from the fact that the center line of the actuator integrated with the control part (spool type control valve part V) changes within the range from the neutral position Cn to the maximum steering positions Ca and Cb, it is near the straight-ahead position. The operating ratio of the control section decreases as the steering angle increases from .

As is clear from the above description of FIG. 10, in the power assist range of the bar handle 7, as the steering angle increases from the neutral steering position, a larger steering force is required.
In the small steering angle range, which is the range used during normal driving, the bar handle 7 can be operated with a light steering force, and in the large steering angle range, which is performed at low speeds, the steering force is heavy, which contributes to preventing the bar handle 7 from turning too much. It has become a thing.

The above hydraulic power steering device can be easily installed in commercially available vehicles by simply replacing the steering system.

Since a rod hole 45 is provided in front of the cylinder 42 through which the piston rod 44 moves forward and backward, sealing measures on the front wall of the cylinder 42 are not required, and by providing an oil passage 57, when the piston rod 44 moves, Σ Lot hole 45
The oil inside can be supplied and discharged, and the piston rod 44 can be smoothly moved back and forth without resistance.

In the embodiment, the steering device of the present invention is installed on a straddle-type four-wheeled vehicle, but the steering device of the present invention can also be applied to other bar-handle type vehicles.

[Effect of the invention].

As described above, the present invention provides a steering device that variably controls the operation of a power assist actuator by changing the arm ratio of the arm based on the torsional phase difference generated in the steering shaft by the steering operation of the bar handle. Although the structure is simple and advantageous from a post standpoint, the degree of freedom in setting the power assist control for a bar handle with a small steering angle can be increased by changing the degree of phase difference generation and the swing radius of the arm.

According to claims 2 and 3, as the steering angle increases, the assist force by the actuator and the operating ratio of the control section become smaller. Since a large steering force is required, the bar handle can be operated with light steering force in the small steering angle range a, which is the range used during normal driving, and the bar handle can be operated with a light steering force in the large steering angle range used at low speeds. This can contribute to preventing excessive cutting.

[Brief explanation of the drawing]

Fig. 1 is an external side view of a straddle-type four-wheel vehicle equipped with the device of the present invention, Fig. 2 is a schematic perspective view showing the steering system, power transmission system, and suspension system, and Fig. 3 shows the arrangement of the actuator body, etc. 4 is a schematic side view of the front part of the vehicle body frame shown in FIG. 4. FIG. 4 is a front view taken from the direction of arrow ■ in FIG. c) is a partial plan view taken along the arrow A-A line in Fig. 5, a partial sectional view taken along the same arrow B-B line, and a partial front view taken from the same arrow C direction, and Fig. 7 shows the actuator when traveling straight. An enlarged vertical side view of the inside of the body. Figures 8 and 9 are the same vertical side views when the steering wheel is turned to the right and left, respectively. Figure 1O is a line explaining the locus of the connection point between the steering shaft and the actuator. It is a diagram. In the drawing, 2 is a steering wheel, 7 is a bar handle 8, 9 is a steering link mechanism, 21 is an upper steering shaft, 25 is a lower steering shaft, 27 is a torsional phase difference generating part, and 29 is a steering link mechanism mounting part. ,■
The control section S is an actuator, 72 is a first arm (phase difference detection section), and 75 is a second arm.

Claims (1)

[Claims] 1. An upper steering shaft that rotates together with the bar handle, a lower steering shaft that has a link mechanism attachment part connected to a steering wheel, and a space between the lower steering shaft and the upper steering shaft. A torsional phase difference generating section arranged, a phase difference detecting section for detecting a relative displacement of the torsional phase difference generating section, and an actuator for power assisting the lower steering shaft in conjunction with the phase difference detecting section. A steering device for a vehicle, characterized in that the transmission force of the actuator is made variable by changing the arm ratio of an arm that rotates integrally around the axis of a steering shaft. 2. The phase difference detection section is the arm disposed on the upper steering shaft, one end of a control section for controlling the operation of the actuator is connected to the arm, and the other end of the control section is oscillated by the vehicle body. The vehicle steering device according to claim 1, wherein the steering device is freely attached. 3. disposing the arm on the lower steering shaft, and connecting one end of the actuator to the arm;
2. The vehicle steering device according to claim 1, wherein the other end of the actuator is swingably attached to the vehicle body.