Steering device for front two-wheel vehicles

Abstract

To inexpensively manufacture a steering device for a swinging three-wheel vehicle that has excellent turning performance and stability and stands on its own when stopped. [Solution] A cross shaft 2 that can rotate freely in the direction of travel is provided at the front of the main frame 1, plain bearings 7 are fixed to both ends of this cross shaft 2, knuckle arms 5 that support the wheels are attached to the left and right plain bearings, operating rods 3, 4 are attached to the left and right knuckle arms 5, and the left and right knuckle arms 5 are connected by a tie rod 6, so that the vehicle can be steered and tilted by operating the operating rods 3, 4.

Description

[Technical Field]

[0001] This invention relates to a steering device for a tiltable tricycle with two front wheels. [Background technology]

[0002] BACKGROUND ART Conventionally, there has been known a swinging three-wheel vehicle that turns stably by tilting the rear wheels and the center part of the vehicle body where a seat can be placed (see, for example, Patent Documents 1 and 2).

[0003] In Patent Document 1, an axis facing approximately in the direction of travel is provided below the handlebar shaft of a normal bicycle, a cross shaft is attached to the axis so that it can rotate freely, and a pair of front wheels are attached to both ends of the cross shaft, creating a front wheel mechanism that allows for stable riding and also allows the body of the bicycle to tilt moderately when turning.

[0004] In Patent Document 2, one wheel is attached to the rear of a central frame that extends from front to back on the skateboard vehicle, a cross shaft is attached to the front so that it can rotate freely around the frame axis, and steerable front wheels are connected to both ends of the cross shaft and to the handle shaft via left and right tie rods, so that the two front wheels can be steered appropriately when the handle shaft is tilted left or right.

[0005] However, in Patent Documents 1 and 2, the vehicle body tilts in conjunction with the steering wheel being turned, which creates the problem of instability when turning at speeds above a certain level as it is unable to balance with the centrifugal force.

[0006] As a solution to this problem, Patent Document 3 proposes a suspension mechanism in which a steering mechanism and a tilting mechanism are connected to the two front wheels via separate links, and the steering angle changes independently of the tilt. However, there is a problem in that the manufacturing cost increases due to the large number of parts and the complex structure. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Published Utility Model 1977-119647 Front Wheel Mechanism Yasuo Ueno [Patent Document 2] Patent Publication No. 2006-62573 Oscillating tricycle Honda Motor Co., Ltd. [Patent Document 3] Patent No. 7001291 Front wheel suspension mechanism and three-wheeled vehicle Future Co., Ltd. Summary of the Invention [Problem to be solved by the invention]

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a steering device that has excellent turning performance and stability, is capable of standing on its own at the driver's will, and has three oscillating wheels, and can be manufactured inexpensively. [Means for solving the problem]

[0009] The main features of this device are a three-wheeled vehicle equipped with a pair of front wheels and a main frame on which a person can sit, and a single rear drive wheel. A cross shaft is provided at the front of the main frame to rotate freely in the direction of travel, making it a swinging vehicle. Slide bearings are fixed to the left and right ends of this cross shaft, and knuckle arms that support the wheels are attached to the left and right slide bearings. The left and right knuckle arms are connected by tie rods so that the two left and right wheels can be steered in the same direction, and operating rods are provided on the left and right knuckle arms so that the three-wheeled vehicle can tilt. [Effects of the Invention]

[0010] The steering can be achieved by rotating the steering rod left and right, just like a regular bicycle, and the vehicle can be tilted by tilting the steering rod in the same direction, allowing for natural steering and leaning, and stable driving. Another advantage of the oscillating tricycle of this invention is that when the vehicle is stopped, the driver can use the left and right steering rods to keep the vehicle standing. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a side view of a swinging three-wheel vehicle according to the present invention (with a driver); [Figure 2]1 is a perspective view of a swinging three-wheel vehicle according to the present invention (with a driver); [Figure 3] FIG. 1 is a perspective view of a driverless oscillating three-wheel vehicle. [Figure 4] FIG. 10 is a detailed explanatory diagram of the front left wheel rotation. [Figure 5] FIG. 1 is a plan view of a vehicle traveling straight and steering left. [Figure 6] FIG. 2 is a front view showing the front of the swinging three-wheel vehicle. [Figure 7] FIG. 7 is a front view showing the front part of the vehicle of FIG. 6 when tilted. [Figure 8] 7 is a front view of the vehicle of FIG. 6 when one front wheel runs over a protrusion. [Figure 9] FIG. 1 is a side view of a folded embodiment of the oscillating tricycle. [Figure 10] FIG. 10 is a side view of an embodiment in which a wind and rain cover is attached. DETAILED DESCRIPTION OF THE INVENTION

[0012] An example of an embodiment of the present invention will be described with reference to the accompanying drawings. Note that front, rear, left, right, up and down refer to directions as seen from the driver's perspective.

[0013] Figure 1 is a side view of one embodiment of the device of this invention. The main frame 1 on which the driver sits and the swing arm supporting the rear wheel equipped with the drive unit are pin-connected via a shock absorber. The two front wheels are mounted on both ends of a cross shaft 2 extending left and right at the front of the main frame, and the driver's footrest is fixed to the main frame between the two wheels. The driver's arms can easily reach the operating rods 3, 4 extending rearward and upward from the steering parts of the two front wheels.

[0014] FIG. 2 is a perspective view of the embodiment of the device of the present invention shown in FIG. 1. The driver can turn the two front wheels or tilt the vehicle by grasping the left and right operating rods 3, 4 and moving them left and right, forward and backward.

[0015] Figure 3 shows the embodiment of Figure 2 without the driver and auxiliary equipment. A bearing is provided in the center of cross shaft 2, and the structure is such that it can bear loads in the front-to-back and up-and-down directions of the vehicle. The cross shaft is journaled and fastened to the front of main frame 1, with the direction of travel as the axis of rotation, making it a swinging vehicle. Operating rods 3 and 4 for steering and tilting are attached to both ends of the cross shaft.

[0016] The device of the present invention will be described in detail below with reference to the reference numerals in FIG. Spherical plain bearings 7 are fixed to both ends of the cross shaft 2, and the central axis of these bearings has appropriate caster and kingpin angles. Knuckle arms 5, which are attached so as to sandwich the spherical plain bearings 7 from above and below, are equipped with axles that rotatably secure the wheels. Tie rods 6 are attached to the arms extending rearward of these knuckle arms 5, connecting the left and right knuckle arms and enabling the left and right front wheels to be steered for tight turns. Operating stalks 4, which extend rearward and upward, are bolted to the knuckle arms 5. The wheels are steered by the driver pushing the left and right operating stalks 3, 4 in opposite directions, and tilting the left and right operating stalks 3, 4 in the same direction causes the wheels to tilt.

[0017] Figure 5 is a plan view of the embodiment of Figure 3 when traveling straight ahead and when the operating culm is turned to the left. When the right operating culm 3 is pushed forward and to the right and the left operating culm 4 is pulled backward and to the left, the front wheel turns just like when turning the handlebars of a bicycle.

[0018] Figure 6 is a front view of the front of the embodiment shown in Figure 3, with the vehicle standing upright. This shows that the vehicle will remain stable and self-supporting as long as the driver holds the steering wheel, whether the vehicle is traveling straight or stopped.

[0019] Figure 7 is a front view of the vehicle when it is tilted, showing that the left and right control shafts 3, 4 are tilted relative to the cross shaft 2, i.e., the driver has intentionally tilted the control shafts 3, 4 to the left. When turning at a certain speed, tilting the vehicle to resist centrifugal force allows it to maintain balance and travel stably.

[0020] Figure 8 is a front view of the vehicle when one of the front wheels runs over a protrusion, showing that the cross shaft 2 rotates relative to the main frame 1, preventing the vehicle from tipping over and allowing it to go over the protrusion with little impact, enabling stable driving. This state also shows that the vehicle can run stably when traversing the shoulder of the road or on a slope.

[0021] FIG. 9 is a side view of the oscillating tricycle of the embodiment when folded up, allowing the vehicle to be stored compactly and allowing the driver to easily get on and off the vehicle from a standing position.

[0022] Furthermore, the rear wheel drive of the device of this invention is not limited to an electric motor, but can also be an electric assist system in which the foot rest is replaced with a pedal crank and the rear wheel is driven by a chain or the like.

[0023] Figure 10 shows an example of a rocking tricycle equipped with a steering device according to the embodiment, equipped with a wind and rain cover to enhance comfort. The tricycle can stand on its own even when stopped, so the driver does not need to put their feet down and will not get wet in the rain. [Industrial Applicability]

[0024] This device requires a small number of parts, many of which can be reused from existing bicycle parts, and the main frame and cross shaft can be made using standard manufacturing methods, making it inexpensive to manufacture. It can turn stably with natural and good handling similar to a bicycle, so it can be used as a leisure vehicle that is fun to operate, and it can also be driven at low speeds by people who are nervous about riding a two-wheeled bicycle, such as elderly people, and it has a wide range of uses. [Explanation of symbols]

[0025] 1. Mainframe 2 Cross Axis 3 Right operating culm 4 Left operating culm 5 Knuckle Arm 6 tie rod 7 Spherical plain bearing

Claims

[Claim 1] In a three-wheeled vehicle equipped with a pair of left and right front wheels and a main frame on which a person can sit, a cross shaft is provided at the front of the main frame so that it can rotate freely in the direction of travel, making it a swinging vehicle; plain bearings are fixed to the left and right ends of this cross shaft; knuckle arms that support the wheels are attached to the left and right plain bearings; the left and right knuckle arms are connected by tie rods so that the two left and right wheels can be steered in the same direction; and an operating rod is provided on the left and right knuckle arms so that the three-wheeled vehicle can tilt.

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