JP4428806B2 - Vehicle steering device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle steering apparatus that changes the direction of a steered wheel by a steering operation by a driver, and more particularly to a steering apparatus that is suitable for use in a small vehicle having a simple structure on which one or two people get on.
[0002]
[Prior art]
In recent years, from the viewpoint of reducing exhaust gas and energy consumption, a small vehicle that can be moved by one or two people has been developed and put into practical use.
Such a small vehicle is configured in a self-supporting form such as a four-wheeled vehicle or a three-wheeled vehicle. For example, as described in JP-A-9-286348, a small engine is used as a power source. It is used as a means that can be easily moved with low exhaust gas with low fuel consumption.
[0003]
In general, such small vehicles are equipped with a steering device that changes the direction of the steered wheels by a steering operation by a driver in order to change the traveling direction of the vehicle.
Such a steering device is provided with a knuckle arm on a knuckle block that rotatably supports a steered wheel, and a tie rod connected to the knuckle arm is moved in the axial direction by the rotational force of the steering wheel. Is to change the direction.
[0004]
And, as a mechanism for moving the tie rod in the axial direction by the rotational force of the steering wheel, a gear box type that converts the rotation of the steering wheel into the swing of the pitman arm by the gearbox and moves the tie rod in the axial direction by the pitman arm, A rack and pinion type in which the rotation of the steering wheel is converted into axial movement of the rack by a pinion and the tie rod is moved in the axial direction by the rack. The rotation of the steering wheel is converted to reciprocation by the link and the tie rod is moved in the axial direction by the link. Various types are known, such as a link type.
[0005]
[Problems to be solved by the invention]
However, in such a steering device, when the steering wheel rides on a protrusion or fits into a recess while the vehicle is running, a force is generated to change the direction of the steering wheel due to the road surface reaction force. As a result, a force to change the direction of the steering wheel (that is, kickback) is generated, which may cause discomfort and fatigue to the driver holding the steering wheel.
As a countermeasure, in a rack and pinion type steering device, a method of interfering with the kickback force generated in the rack by providing a hydraulic damper in parallel with the rack can be considered. However, the rack and pinion type steering device itself has a complicated structure and a large size. Although the gravity is increased, if a hydraulic damper is provided, the structure becomes more complicated and the gravity increases. Needless to say, if the installation method and type of the hydraulic damper are not devised, the size is considerably increased.
[0006]
Here, in a small vehicle as described above, since a structure is simplified and a reduction in size and weight is particularly required, a link type steering device that is simpler in structure and smaller in weight than a rack and pinion type or a gear box type is adopted. Is advantageous. In addition, the link type steering device has a smaller ratio when converting the rotational force of the steering wheel to the axial movement force of the tie rod than the rack and pinion type and the gear box type. Since the steering load is originally small, there is no problem with the steering load even if a link type steering device is employed.
However, in the link type steering device, since the conversion ratio is small, the kickback force is easily transmitted to the steering wheel, and a countermeasure against the buffer is particularly required as compared with the rack and pinion type and the gear box type.
[0007]
The present invention has been made in view of the above-described conventional circumstances, and an object thereof is to provide a vehicle steering apparatus having a buffering function against kickback.
It is another object of the present invention to provide a vehicle steering apparatus that is particularly suitable for a small vehicle.
Further objects of the present invention will be apparent from the following description.
[0008]
[Means for Solving the Problems]
A vehicle steering apparatus according to the present invention includes a knuckle block that rotatably supports a steered wheel, a knuckle arm provided on the knuckle block, and a tie rod connected to the knuckle arm, and a kickback that acts in the axial direction. A damper mechanism for absorbing force is interposed coaxially with the tie rod.
Therefore, the kickback force transmitted through the tie rod can be buffered by the damper mechanism, and since this damper mechanism is disposed coaxially with the tie rod, it can be buffered without increasing the size of the device. Functions can be added.
[0009]
Furthermore, in the steering apparatus of the present invention, hydraulic cylinder type damper mechanisms are respectively interposed in the left and right tie rods connected to the left and right steering wheels, and pipes for circulating oil between these cylinders are connected between the cylinders.
Therefore, the damper mechanism can use various types using a compressive fluid such as air or an elastic body, but it does not generate a damper function during normal steering by using a hydraulic cylinder type in particular. In addition, it is possible to easily adjust and set so that the driver does not feel uncomfortable in steering and a large buffering effect is generated against kickback. Furthermore, since oil is circulated between these hydraulic cylinders, when one tie rod is contracted by the kickback force, the other tie rod can be operated so as to be extended. Alignment is always kept constant.
[0010]
Furthermore, the present invention includes a link mechanism that directly transmits the rotational force of the steering wheel to the tie rod to move the tie rod in the axial direction, that is, is applied to a link type steering apparatus.
Therefore, it is possible to add a buffer function for kickback without impairing the advantages of the link type steering device, which is advantageous in that the structure is simple and small and light, and for example, steering that can satisfy the demands required for small vehicles An apparatus can be realized.
It should be noted that the present invention is suitable for application to a link type steering device, but the intended effects can be obtained even when applied to other types of steering devices such as a rack and pinion type and a gear box type. Even if the present invention is applied not only to a small vehicle amount but also to a general vehicle having a steering device, the desired effects can be obtained.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be specifically described with reference to an embodiment shown in the drawings. In this example, the present invention is applied to a link type (particularly, center arm type) steering device used for small vehicles.
As shown in FIGS. 1 to 3, the small vehicle of this example is a four-wheeled vehicle having two wheels on the front wheel 1 and the rear wheel 2, and one occupant (driver) is seated in the center. A single seat driving seat 3 is provided.
The basic vehicle structure of this small vehicle is a frame-type vehicle body frame 4 made of a metal pipe material such as aluminum and covered with a resin body cover 5, and further, above the body cover 5. A resin roof panel 6 is arranged to cover the upper part of the seating seat 3 of the occupant to constitute a cabin.
[0012]
A steering wheel 7 is provided in the driver's seat, and by applying a steering force from the steering wheel 7 via a steering device to be described later, the left and right front wheels 1 as steering wheels change directions and the traveling direction of the vehicle Can be changed arbitrarily.
A frame-type swing frame 8 is attached to the rear portion of the vehicle body frame 4 so as to be swingable up and down, and a power unit 9 in which an engine, a transmission, a differential mechanism, and the like are integrated is provided on the swing frame 8. The left and right rear wheels 2 as drive wheels are connected to the power unit 9 and suspended by swinging of the swing frame 8 and driven by the output from the power unit 9.
[0013]
A pair of leading arms 10 are provided at the front portion of the vehicle body frame 4, and these leading arms 10 are attached so as to be swingable up and down around a pivot 11. A suspension unit (not shown) in which a suspension spring and a shock absorber are assembled is provided between each leading arm 10 and the vehicle body frame 4.
A knuckle block 12 is provided at the tip of each leading arm 10 so as to be rotatable in the steering direction, and the steering wheel 1 is rotatably supported by each knuckle block 12.
[0014]
As shown in detail in FIG. 4, the knuckle block 12 is provided at the tip of the leading arm 10 so as to be rotatable in the steering direction about a central shaft 13 (attachment pin: not shown). The tip of the tie rod 15 of the steering device is connected to the protruding knuckle arm 14.
In this steering apparatus, a plate-like center arm 18 is fixed to a lower end of a steering column 17 extending from a steering wheel 7, and a base end of a tie rod 15 is connected to the center arm 18. The arm 18 is rotationally displaced about the steering column 17, thereby moving the tie rod 15 in the axial direction to the right or left and turning the knuckle block 12 to the right or left.
[0015]
The tip of the tie rod 15 is rotatably connected to the knuckle arm 14 via a pin 19, and the base end of the tie rod 15 is rotatably connected to a center arm 18 via a pin 20. 15, a knuckle arm 14 constitutes a link mechanism that transmits the rotational force of the steering wheel 7 to turn the steering wheel 1.
[0016]
As shown in detail in FIGS. 5 and 6, the tie rod 15 has a structure in which a hydraulic cylinder is interposed coaxially, and the base end of the cylinder body 22 is connected to the center arm 18, and the piston rod extends coaxially from the cylinder body 22. The tip of 23 is connected to the knuckle arm 14.
A small-diameter portion is formed at a substantially central position inside the cylinder body 22 by an annular step portion 24, and the piston 25 provided at the base end of the piston rod 23 slides on this small-diameter portion in the normal state shown in FIG. It fits freely.
[0017]
Oil chambers 26a and 26b containing oil are formed on both sides of the small diameter portion 24 inside the cylinder body 22, and the piston 25 is held in the normal positions shown in FIG. 5 in these oil chambers 26a and 26b. Return springs 27a and 27b are provided for biasing.
Reference numeral 28 in the figure denotes a spring seat for engaging the return springs 27a and 27b with the piston 25. Also, 29 in the figure is a lid member that closes the opening at the tip of the cylinder body 22, and the piston rod 23 penetrates the lid member 29 and is movable in the axial direction, and by a sealing material 30 provided on the lid member 29. The oil tightness of the oil chamber 26a is maintained.
[0018]
The piston 25 is formed with an orifice 31 that communicates between the oil chambers 26a and 26b. When the piston 25 moves by the kickback force as shown in FIG. 6, the orifice 31 passes between the oil chambers 26a and 26b. Oil flows and thereby generates a damping force with respect to the movement of the piston 25 (that is, relative movement between the cylinder body 22 and the piston rod 23).
The cylinder body 22 is formed with ports 33a and 33b communicating with the oil chambers 26a and 26b, respectively. These port ports 33a and 33b are respectively piped to the same ports 33a and 33b of the hydraulic cylinder constituting the other tie rod 15. It communicates via 34a, 34b.
[0019]
Therefore, for example, when the capacity of the oil chamber 26b of one tie rod becomes small as shown in FIG. 6 with respect to the capacity change of the oil chambers 26a, 26b accompanying the movement of the piston 25, the pipe is connected to the oil chamber 26b of the other tie rod. The excess oil is temporarily allowed to flow through 34b to increase its capacity, whereby excess oil resulting from the decrease in the capacity of the oil chamber 26a of the other tie rod is removed via the pipe 34a to the oil chamber 26a of one tie rod. In general, when one tie rod 15 is contracted, the other tie rod 15 is slightly extended to keep the wheel alignment constant.
[0020]
Here, the urging force of the return springs 27a and 27b holds the piston 25 in a neutral position as shown in FIG. 5 with respect to the axial force applied to the tie rod 15 by a normal steering operation. As shown in FIG. 6, the kickback axial force is set so as to allow the piston 25 to move, and when the kickback force is applied from the steering wheel 1, the above-described attenuation due to the expansion and contraction of the tie rod 15. A buffering effect is generated by force, and during normal steering operation, the expansion and contraction of the tie rod 15 is suppressed so that the steering operation does not feel strange.
[0021]
Next, the operation of the steering apparatus of this example will be described.
First, at the time of normal steering, when the driver rotates the steering wheel 7, the center arm 18 rotates, whereby the tie rod 15 moves axially to the right or left to move the knuckle block 12 to the right or left around the pin 13. By turning, the left and right steering wheels 1 can be turned in a desired direction.
When a kickback that suddenly changes the direction of the steered wheel 1 occurs due to the road surface reaction force during traveling, the kickback force is buffered by the damping force of the hydraulic cylinder mechanism of the tie rod 15 and is not transmitted to the steering wheel 7. It is like that.
[0022]
Further, in such a buffering operation, as shown in FIG. 7, when one (right steering wheel side) tie rod 15 contracts, oil circulates between the other (left steering wheel) tie rod 15 through pipes 34a and 34b. On the other hand, the tie rod 15 on the other (left steered wheel) extends, and the wheel alignment such as the toe angle set between the left and right steered wheels 1 is kept constant.
Since kickback due to such road reaction force occurs temporarily, when the kickback force is lost, the piston 25 is immediately returned to the neutral position shown in FIG. 5 by the return springs 27a and 27b, and the left and right tie rods 15 Will return to the normal state with equal length.
[0023]
【The invention's effect】
As described above, according to the present invention, since the damper mechanism for absorbing the kickback force is coaxially interposed in the tie rod, the damper mechanism can be used regardless of the rack pinion type, gear box type, link type or the like. Can be incorporated without protruding from the components of the steering device, and a buffer function can be added without increasing the size of the steering device.
In addition, according to the present invention, the hydraulic cylinder type damper mechanism is interposed between the left and right tie rods, and the pipe for circulating oil between these cylinders is provided. The wheel alignment such as the toe angle set between the left and right steering wheels can always be kept constant.
Further, according to the present invention, since the link type steering device that directly transmits the rotational force of the steering wheel to the tie rod is used, there is a demand for a small vehicle by using a small and light link type steering device with a simple structure. It can be satisfied and a buffering function against kickback can be realized.
[Brief description of the drawings]
FIG. 1 is a perspective view of a small vehicle according to an embodiment of the present invention viewed from the front side.
FIG. 2 is a perspective view seen from the back side of the small vehicle according to the embodiment of the present invention.
FIG. 3 is a bottom view in plan view of a small vehicle according to an embodiment of the present invention.
FIG. 4 is a perspective view showing an overall configuration of a steering apparatus according to an embodiment of the present invention.
FIG. 5 is a sectional view showing a hydraulic damper mechanism according to an embodiment of the present invention in a normal state.
FIG. 6 is a cross-sectional view showing a hydraulic damper mechanism according to an embodiment of the present invention in a state when a damping force is generated.
FIG. 7 is a diagram for explaining the operation of the steering device according to the embodiment of the present invention.
[Explanation of symbols]
1: Front wheel (steering wheel), 7: Steering wheel,
12: Knuckle block, 14: Knuckle arm,
15: Tie rod, 17: Steering column,
18: Center arm, 22: Cylinder body,
23: piston rod, 25: piston,
26a, 26b: oil chamber, 27a, 27b: return spring,
31: Orifice, 33a, 33b: Port,
34a, 34b: pipes,

Claims (2)

In a vehicle steering apparatus including a knuckle block that rotatably supports a steered wheel, a knuckle arm provided on the knuckle block, and a tie rod connected to the knuckle arm.
The left and right tie rods connecting the right and left steered wheels respectively interposed hydraulic cylinder type damper mechanism for absorbing the kickback force acting axially on the tie rod coaxially, circulating oil between these cylinders A steering apparatus for a vehicle , wherein a pipe is connected between the cylinders . The vehicle steering apparatus according to claim 1 ,
A steering apparatus for a vehicle, comprising a link mechanism that transmits a rotational force of a steering wheel directly to a tie rod to move the tie rod in an axial direction.

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