JP2011126514A - Front double-wheel type tricycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a front double-wheel type tricycle having compact construction for actualizing good differential operation while developing improved travelling performance and control stability. <P>SOLUTION: A steering stem 122 is rotatably supported on the front part of a body frame, and a pair of right and left front wheels 106 are supported on both sides of a chain type differential unit 10 mounted directly or indirectly on the steering stem 122. The differential unit 10 is constructed rotatable integrally with the steering stem 122 to support the front wheels 106 via a pair of right and left arms 36, 37, respectively. A front fork is arranged between mutually turnable upper and lower arms constituting the arms 36, 37. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a front two-wheeled tricycle having a pair of left and right front wheels at the front of a vehicle body, and particularly to a vehicle in which the front wheels are operated.

  In vehicles such as motorcycles and bicycles, for example, when the road surface is wet, the front wheels are slippery during sudden braking or the like, and there is a possibility that the vehicle may fall over if left as it is. On the other hand, vehicles such as four-wheel vehicles and so-called ATVs (all train vehicles) are generally excellent in running stability. However, these four-wheeled vehicles have a wider vehicle width than two-wheeled vehicles, and not only are they difficult to travel in narrow spaces, but also have a large turning radius when turning, and thus both have advantages and disadvantages.

  Conventionally, for example, in the tricycle described in Patent Document 1, a differential device composed of a substantially parallel link mechanism is provided above the front wheel so that a lean operation can be performed, and the front wheel can be differentially operated via this differential device. It can be done. In the actual vehicle, since the differential gear occupies a large arrangement space, the upper part of the front wheel is covered with a large cover.

  Moreover, in the tricycle described in Patent Document 2, a pair of swing arms extending in the front-rear direction are pivotally supported on the left and right ends of the front arm extending from the steering shaft, and the front wheels are supported on the free ends of the swing arms, and each swing One end of a cushion spring is connected to the arm, and the other end of each cushion spring is differentially connected via a motion conversion means.

JP 2006-160254 A JP-A-5-139357

  For example, in the tricycle described in Patent Document 1, in order to make the left and right front wheels differential, so-called seesaw type is moved up and down. In this seesaw system, the width between the left and right front wheels is considerably large in order to secure a predetermined differential amount. Conversely, if the width is limited, it is difficult to secure the differential amount.

  More specifically, consider a case in which it is desired to set the vehicle body width to be smaller than the handle width. For example, when it is necessary to increase the diameter of the front wheel or to increase the center distance (tread) between the left and right front wheels (under the condition of maintaining the maximum lean angle), the two arm members of the seesaw structure described above are lengthened. Must. Then, the whole mechanism becomes large and bulky, and the handle width is greatly exceeded. In this case, although it is possible to run lean, the result is that the handling performance is not as good as that of a normal motorcycle.

  In view of such circumstances, an object of the present invention is to provide a front two-wheeled three-wheeled vehicle that realizes a good differential operation while being compact and is excellent in running performance and handling performance.

  The front two-wheel tricycle of the present invention is a front two-wheel tricycle having a pair of left and right front wheels and a rear wheel, and a steering stem is rotatably supported at the front part of a vehicle body frame. Alternatively, the pair of left and right front wheels are supported on both sides of an indirectly mounted chain type differential unit.

  Further, in the front two-wheeled tricycle of the present invention, the differential unit supports the front wheel via a pair of left and right arms in the immediate vicinity of the front fork supported by the steering stem. The arm is differentially operated in the vertical direction along a pair of linear guide rails arranged.

  Further, in the front two-wheeled tricycle of the present invention, a chain having a traveling track in the vertical direction is wound around the inside of the guide rail, and the arm is moved up and down via a pair of sliders connected to both sides of the chain. It is made to move.

  Further, in the front two-wheeled tricycle of the present invention, the chain is mounted two front and rear in the differential unit, and can run in synchronization with each other.

  In the front two-wheeled tricycle of the present invention, an auto tensioner capable of adjusting the tension is mounted at an appropriate position of the chain.

  In the front two-wheel tricycle of the present invention, the differential unit is connected and supported to the front fork via a link mechanism, and can be interlocked and followed by the buffering operation of the front fork.

  Further, in the front two-wheel tricycle of the present invention, the differential unit is configured integrally with the steering stem and supports the front wheels via a pair of left and right arms, and constitutes the arms. A front fork is arranged between the rotatable upper arm and the lower arm.

According to the present invention, a differential unit is configured using a linear guide rail and a slider, and a large distance between the ground contact points of the front wheels can be ensured while being small. In this case, by configuring the differential mechanism using a chain, the differential amount when the left and right front wheels are differentiated can be set large. As a result, the differential amount can be effectively secured, so that good turning performance can be realized, and the differential unit can be substantially made compact. As a result, it is possible to realize both handling performance similar to that of a two-wheeled vehicle and traveling stability similar to that of a four-wheeled vehicle.
In particular, by reducing the unsprung weight of the front fork, further steering stability can be improved.

1 is a perspective view showing an overall configuration of a front two-wheel tricycle according to the present invention. 1 is a side view showing an overall configuration of a front two-wheel tricycle according to the present invention. It is a perspective view which shows the coupling relationship etc. with the front fork of the differential unit which concerns on this invention. It is sectional drawing which follows the AA line of FIG. 2 which shows the structural example of the differential unit which concerns on this invention. It is a perspective view which shows the example of a structure of the differential unit which concerns on this invention in principle. It is a front view which shows the effect | action of the differential unit which concerns on this invention. It is a right view of the front two-wheeled tricycle which concerns on the 2nd Embodiment of this invention. It is a perspective view which shows the structural example of the vehicle body frame in the front two-wheeled tricycle which concerns on the 2nd Embodiment of this invention. It is sectional drawing which follows the BB line of FIG. 7 which shows the structural example of the differential unit which concerns on the 2nd Embodiment of this invention. It is a figure which shows the basic structure of the steering mechanism in the front two-wheeled tricycle which concerns on the 2nd Embodiment of this invention. It is a figure which shows the structural example around the front fork in the front two-wheeled tricycle which concerns on the 2nd Embodiment of this invention.

Hereinafter, preferred embodiments of a front two-wheeled tricycle according to the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of a front two-wheel tricycle according to the present invention, and FIG. 2 is a side view thereof. First, the overall configuration of the front two-wheeled tricycle 100 will be described with reference to FIGS. 1 and 2. In addition, in the drawings used in the following description including these drawings, the front of the vehicle is indicated by an arrow Fr, the rear of the vehicle is indicated by an arrow Rr, and the lateral right side of the vehicle is indicated by an arrow R as necessary. The left side of the vehicle is indicated by an arrow L.

  The front two-wheel tricycle 100 shown in FIG. 1 may be used for, for example, so-called off-road, and a steering head pipe 101 is disposed at the front upper part of the vehicle body, and a steering stem (not shown) rotates in the steering head pipe 101. It is movably inserted. An upper bracket 102 and a lower bracket 103 are coupled to the upper and lower ends of the steering stem, respectively, and a pair of left and right front forks 104 are attached thereto. A handle 105 is attached to the upper bracket 102, and a pair of left and right front wheels 106, which are operating wheels rotatably supported by a lower end of a differential unit 10 described later, through a front fork 104 by operation of the handle 105. Can be steered.

  From the steering head pipe 101, a pair of left and right main frames 107A constituting the vehicle body frame 107 extend obliquely downward toward the rear of the vehicle body, and a down tube 107B extends substantially vertically downward. The down tube 107B branches to the left and right as a lower frame 107C in the vicinity of the lower part, and the pair of lower frames 107C extends downward and then bends at a substantially right angle toward the rear of the vehicle body. The frame 107D is connected to each rear end portion of the main frame 107A.

  A water-cooled engine 108 as a driving source is mounted in a space surrounded by the pair of left and right main frames 107A, the down tube 107B and the lower frame 107C, and the body frame 107D, and a fuel tank 109 is disposed above the engine 108. The fuel supply port is plugged by a cap 110. A seat 111 is disposed behind the fuel tank 109. A radiator 112 is disposed in front of the engine 100.

  A front end portion of the rear swing arm 113 is supported by a pivot shaft 114 so as to be able to swing up and down on a pair of left and right body frames 107D provided at a substantially lower center in the front-rear direction of the vehicle body. A rear wheel 115 as a driving wheel is rotatably supported at the rear end portion of the rear swing arm 113. The rear swing arm 113 is suspended from the vehicle body via a link mechanism and a shock absorber (rear wheel suspension device) connected thereto.

  A fuel pump unit is disposed in the fuel tank 109, and fuel is supplied to the engine 108 by the fuel pump unit. On the other hand, although not shown in detail, an air cleaner box is disposed on the rear side of the above-described shock absorber, and the air cleaner box and the engine 108 are connected via an intake passage. Although not shown in FIG. 1, the intake passage is connected to an intake port provided in the cylinder head of the engine 108, and a throttle body is disposed as a part of the intake passage along the way. The throttle body is provided with a fuel injector, and a predetermined amount of fuel is supplied to the fuel injector at a predetermined timing from a fuel pump unit.

  In this example, the engine 108 is a four-cycle single cylinder engine, for example, and an exhaust pipe 116 is connected to an exhaust port provided in the cylinder head. In FIG. 1, an exhaust pipe 116 extends from the cylinder head to the right side of the vehicle and further extends rearward, and is connected to a silencer (muffler) 117 constituting an exhaust device. In FIG. 1, a part of the silencer 117 (near the rear part) is shown, but the silencer 117 is arranged on the upper right side of the rear wheel 115.

  The differential unit 10 is mounted along the front fork 104 in the immediate vicinity of the front fork 104 and supports the left and right front wheels 106 so as to be differentially operable. As shown in FIG. 3, a long casing or casing 11 is provided, and the constituent members of the differential unit 10 are arranged and configured in the casing 11. In FIG. 3, the detailed structure in the casing 11 is not shown. The casing 11 has a substantially hollow structure with a substantially rectangular cross section, and can be rotated by a support shaft 12 horizontally mounted on the lower ends of the left and right front forks 104 (FIG. 3, arrow B). Supported. Further, in this example, as shown in FIG. 3, a buffer link arm 13 that extends forward from the vehicle body side is provided, and a bracket 14 that is rotatably connected to the tip end portion via a support shaft 15 is provided inside the casing 11. It is fixed in place (near the upper part of the casing 11).

  As shown in FIG. 3, the link arm 13 may be disposed between the left and right front forks 104 in this example. Further, in this case, the base end side of the link arm 13 is rotatably supported via the support shaft 17 by a bracket 16 fixed to the front fork 104 as shown in FIG. The bracket 16 may be provided separately, or may be fixed to the lower bracket 103 of the steering stem using the lower bracket 103. By supporting the casing 11 on the front fork 104 through the link mechanism including the link arm 13 and the like in this way, the casing 11 can interlock and follow the buffering operation (extension / contraction) of the front fork 104. The moving unit 10 can use the buffer function of the front fork 104.

Further, the differential unit 10 will be described with reference to FIGS. 4 is a cross-sectional view taken along line AA in FIG. A rotating shaft of a sprocket, which will be described later, is disposed along the line AA. In this embodiment, the differential mechanism of the differential unit 10 is configured using a chain. As shown in FIGS. 4 and 5, rotary shafts 18 and 19 are arranged in the front-rear direction at a central position in the left-right direction above and below the casing 11, and these rotary shafts 18 and 19 each have a pair of front and rear bearings 20. It is supported rotatably via. A pair of sprockets 21 and 22 are attached to the front and rear shaft ends of the rotary shafts 18 and 19, respectively, and a front chain 23 is wound between the front sprockets 21 and 22, and the rear sprocket 21 and 22 are wound around each other. A rear chain 24 is wound around 22 between them. These chains 23 and 24 run along the longitudinal direction (vertical direction) at a substantially central portion in the casing 11 and run in synchronization with each other.

On the other hand, a pair of guide rails 25 and 26 are arranged in parallel to each other along the longitudinal direction on both the left and right sides of the casing 11. These guide rails 25 and 26 are arranged on the outer side in the left-right direction and in the center in the front-rear direction with respect to the chains 23 and 24, but are configured as linear motion type guide rails. The guide rails 25 and 26 support the sliders 27 and 28 movably in the longitudinal direction, respectively. In FIG. 5, the chains 23 and 24 and the sliders 27 and 28 are shown.
The connection relationship is shown in principle and schematically, which will be described later.

FIG. 4 shows a specific configuration of the guide rails 25 and 26 and the sliders 27 and 28. Linear motion bearings 29 and 30 are engaged with the guide rails 25 and 26. These linear motion bearings 29 and 30 are slidable in the axial direction with respect to the guide rails 25 and 26, and are restricted in the rotational direction. Is done. The linear motion bearings 29 and 30 and their housings 31 and 32 are coupled and fixed to each other via a key 33. The housing 31 is connected to the front and rear chains 23, 2 via a connecting plate 34.
4, and the housing 32 is connected to the front and rear chains 23,
24. The sliders 27 and 28 are coupled to the housings 31 and 32, respectively, thereby being connected to the front and rear chains 23 and 24 while maintaining a predetermined relative positional relationship.

As described above, the left and right sliders 27, 2 connected to the front and rear chains 23, 24, respectively.
8 moves up and down along the guide rails 25 and 26 as the chains 23 and 24 travel, that is, performs differential operation. In this case, the height direction position of the sliders 27 and 28 is set to a substantially middle point of the distance between the axes of the upper and lower rotary shafts 18 and 19 or to an extent that the sliders 27 and 28 face each other at an appropriate upper position. When one of the sliders 27 and 28 is raised in the differential operation, the other is lowered.

  The left and right sliders 27 and 28 are firmly fixed and fixed with arms 36 and 37 for supporting the front wheel 106 on the outer sides in the left and right direction. A front wheel 106 is rotatably supported on the lower ends of these arms 36 and 37 via an axle 106a. The front wheel 106 may be provided with a brake disk 118.

In the above case, as schematically shown in FIG.
An auto tensioner 38 capable of adjusting the tension may be attached. Although a detailed description and illustration of the auto tensioner 38 are omitted, a housing is connected to one of adjacent chain pieces connected to each other in the chains 23 and 24, and a male screw (bolt) is connected to the other. The housing accommodates a tension adjuster with a spring seat that can reciprocate by a predetermined stroke in the running direction of the chains 23 and 24 (restrained in the rotational direction). The tension adjuster is formed with a female screw that is screwed with the male screw, and a compression spring is mounted on the outer periphery thereof.

In such an auto tensioner 38, each time the chains 23 and 24 are loosened, the male screw and the female screw are appropriately tightened, whereby the tension of the chains 23 and 24 can be adjusted appropriately. It should be noted that when an overload is applied to the auto tensioner 38 for some reason, it is also possible to exhibit a so-called “degree-of-contact” function and prevent plastic deformation of the mounted spring.

  In the front two-wheeled tricycle 100 of the present invention, the rider M (see FIG. 1) rotates the handle 105 in the direction in which the steering wheel 105 is desired to be steered, and moves the weight appropriately to the steering side. The front wheel 106 supported by the vehicle 10 can be steered. According to the present invention, first, it is possible to realize both handling performance similar to that of a two-wheeled vehicle and traveling stability similar to that of a four-wheeled vehicle.

More specifically, the differential unit 10 is configured by using the direct-acting guide rails 25 and 26 and the sliders 27 and 28, and a large distance between the grounding points of the front wheels 106 can be ensured while being small. For example, when steering to the right as shown in FIG. 1, the right slider 27 is raised and the left slider 28 is lowered. At this time, as shown in FIG. 6, the reaction force F from the road surface is transmitted to the front and rear chains 23 and 24 via the sliders 27 and 28, and each of the chains 23 and 24 (four in this embodiment in total) is transmitted. Countering with the drag force f, the reaction force F can be stably received as a whole. FIG. 6 shows a state when the front two-wheeled tricycle 100 tilts with respect to a horizontal road surface.

In the front two-wheel tricycle 100 of the present invention, as shown in FIG. 6, the distance S between the ground contact points of the left and right front wheels 106 when turning is increased as the vehicle body inclination angle increases from the minimum distance S ₀ when the vehicle body is vertical. And driving stability can be guaranteed.
Further, in the present invention, the differential mechanism is configured by using the chains 23 and 24, so that the differential amount when the left and right front wheels 106 are differentially set is set larger than when the link mechanism is used. Can do. As a result, even when the vehicle width is limited, the differential amount can be effectively ensured, so that good turning performance can be realized and the differential unit 10 can be made substantially compact.

By using the two chains 23 and 24 at the front and rear as described above, the rotational torque received by the arms 36 and 37 that support the front wheel 106 during braking is shared with the sliders 27 and 28 to receive the linear motion guide portion. The burden of In addition, the safety of the differential mechanism operation can be improved by taking into consideration the damage of parts and the loosening of screws.

  Further, in actual use, for example, the wheel is likely to slip over a wet manhole or the like, and particularly when subjected to lateral G (lateral acceleration) during cornering, the wheel becomes even more slippery. In this case, one of the right and left front wheels 106 can pass on the asphalt road surface, and it becomes much harder to slip than in the case of a two-wheeled vehicle. In the front two-wheeled tricycle 100 of the present invention, a large distance S between the grounding points of the front wheels 106 can be ensured during cornering, and high stability can also be realized in this respect.

Further, even when the chains 23 and 24 are loosened with time in actual use, the tension of the chains 23 and 24 can always be properly adjusted and maintained by the auto tensioner 38. This ensures a smooth and proper operation of the differential unit 10.

Next, a second embodiment of the front two-wheel tricycle 100 according to the present invention will be described. FIG. 7 is a right side view of the front two-wheeled tricycle 100 according to the second embodiment of the present invention. In the following description, the same reference numerals are used for members that are substantially the same as or correspond to those in the above-described embodiment. I will explain.
By the way, the above-described differential unit 10 is attached to the vehicle body via the front fork 104, that is, has a support structure in which the front wheel 106 and the differential unit 10 are suspended on the front fork 104. The front wheel 106 and the differential unit 10 have a so-called unsprung load on the front fork 104, and the weight of the front wheel 106 and the differential unit 10 is considerably increased. For example, when traveling on a rough road surface, a large inertial force acts on the front wheels 106, and therefore, there is a case where vibration transmission to the driver is affected in relation to the damping action by the front fork 104.

  Therefore, in the second embodiment of the present invention, a front two-wheeled tricycle 100 in which the unsprung weight of the front fork is effectively reduced is provided in order to further improve the maneuverability. Typically, as shown in FIG. 7, the front fork 104 is disposed between the differential unit 10 and the front wheel 106 to reduce the unsprung weight of the front fork 104.

  7 and 8, the front two-wheeled tricycle 100 according to the second embodiment will be described more specifically. The support frame 119 extends forward so as to be forwardly lowered from the vicinity of the upper portion of the down tube 107B constituting the vehicle body frame 107 and substantially parallel to the central axis 101A of the steering head pipe 101. The lower end of the support frame 119 is at a height position substantially the same as the lower frame 107C. A pair of support frames 120 extend from the front ends of a pair of left and right lower frames 107C constituting the lower part of the body frame 107 toward the front. The extended ends of the support frame 119 and the support frame 120 are fixed to the bottom plate 121 at the other end, and the bottom plate 121 is extremely rigidly supported by coupling these members to each other. The bottom plate 121 itself has necessary and sufficient rigidity and is disposed between the left and right front wheels 106.

  A steering stem 122 is rotatably inserted and supported in the steering head pipe 101 via a bearing (not shown). The steering stem 122 extends forward and downward from the steering head pipe 101 along the central axis 101 </ b> A, and a lower end thereof is rotatably supported by the bottom plate 121. Although not shown in detail in the bolt plate 121, a bearing 123 for supporting the steering stem 122 is attached. A handle 105 is attached to the upper bracket 102 coupled to the upper end portion of the steering stem 122, and the basic structure of the steering mechanism is configured as shown in FIG. As a result, the steering stem 122 rotates left and right according to the left and right turns of the handle 105.

  The differential unit 10 is attached to the front side of the steering stem 122 so as to correspond to the left and right of the handle 105. In this case, as shown in FIG. 9, the entire differential unit 10 is fastened and fixed to the steering stem 122 by a bolt 125 or the like via a mounting bracket 124, that is, the steering stem 122 and the differential unit 10 are configured to be integrally rotated. . Although the mounting bracket 124 is not shown in detail in FIG. 7 or the like, the mounting bracket 124 has a predetermined length or a plurality of the mounting brackets 124 disposed along the steering stem 122 that are coupled to each other. Support rigidity is ensured. As shown in FIG. 9, the basic configuration of the differential unit 10 itself is the same as that of the above-described embodiment.

  The left and right sliders 27 and 28 of the differential unit 10 are joined and supported by arms 36 and 37 for supporting the front wheel 106 on the outer sides in the left and right direction. A front wheel 106 is rotatably supported on the lower ends of these arms 36 and 37 via an axle 106a. Here, in the second embodiment, as shown in FIG. 10, the arm 36 is composed of an upper arm 36A and a lower arm 36B that are connected to each other, and they are coupled to each other at their pivot fulcrum 36C. The upper arm 36A is pivotally supported on the differential unit 10 side at its upper end, and the lower arm 36B supports the front wheel 106 at the end opposite to the rotation fulcrum 36C. Further, a front fork 104 is stretched between the rotation fulcrum 36C of the upper arm 36A and the lower arm 36B, respectively. The configuration of the arm 37 is the same as that of the arm 36.

  The front fork 104 is configured to be extendable and contractible in the longitudinal direction, and has a bumper function. For example, in its basic configuration, it may be composed of an inner tube and an outer tube that can be fitted and slid with each other, and may have a configuration substantially similar to a general motorcycle front fork that incorporates a spring and oil. . In that case, the inner tube arranged on the upper side is fixed at a predetermined position on the differential unit 10 side, and the outer tube expands and contracts from the inner tube. The axle 106a supported by the lower arm 36B coupled to the lower end of the outer tube is configured to move up and down according to the expansion and contraction of the front fork 104.

Also in the front two-wheeled tricycle 100 according to the second embodiment, it is possible to guarantee the running stability during turning by the original action of the differential unit 10 and to realize good turning performance.
Particularly in the second embodiment, first, the differential unit 10 is directly attached to the front side of the steering stem 122, and the front wheels 106 are rotatably supported by the lower ends of the arms 36 and 37 via the axles 106a. The front fork 104 is disposed between the differential unit 10 and the front wheel 106, and the unsprung weight of the front fork 104 can be significantly reduced by such a front wheel support structure.

  By disposing the front fork 104 and reducing its unsprung weight, when traveling on an uneven road surface, first, the front fork 104 effectively absorbs the impact from the road surface, and the impact on the differential unit 10. The load can be significantly reduced. Further, the inertial force on the front wheel 106 can be reduced, and the vibration transmission to the driver can be greatly improved.

  Further, in the support structure of the differential unit 10, members such as the support frame 119 and the support frame 120 are coupled to each other using the down tube 107B, and a so-called truss structure is configured by these members. There are advantages such as effectively strengthening the rigidity strength of the support structure around the front wheel 106, ensuring stable operation even when a large load is applied particularly during braking, and ensuring high traveling safety.

Further, the differential unit 10 is substantially directly attached to the steering stem 122, that is, the inertial load in the rotational direction of the differential unit 10 with respect to the steering stem 122 serving as the steering central axis is made as small as possible. Thereby, steering performance, running stability, etc. can be improved.
In addition, by directly attaching the differential unit 10 to a single steering stem 122, the body frame 107 has a narrow and compact structure around the front, realizing a substantial increase in steering angle and good steering performance. can do. In addition, the lightweight and compact configuration makes it possible to obtain a steering feeling equivalent to that of a two-wheeled vehicle.

As mentioned above, although this invention was demonstrated with various embodiment, this invention is not limited only to these embodiment, A change etc. are possible within the scope of the present invention.
In the above-described embodiment, the differential mechanism is configured using a chain and a sprocket. However, the differential mechanism is not limited thereto, and may be configured by, for example, a wire, a belt and a pulley, or a rack and pinion mechanism. It is also possible to configure a single chain and upper and lower sprockets wound around the chain.

10 Differential unit, 11 Casing, 12 Support shaft, 13 Link arm, 18, 19
Rotating shaft, 20 bearings, 21, 22 sprocket, 23, 24 chain, 25, 26
Guide rail, 27, 28 Slider, 29, 30 Linear motion bearing, 31, 32 Housing, 36, 37 Arm, 36A Upper arm, 36B Lower arm, 100 Front two-wheel tricycle, 105 Handle, 104 Front fork, 106 Front wheel, 119 Support frame , 120 support frame, 121 bottom plate, 122 steering stem, 124 mounting bracket.

Claims (7)

A front two-wheeled tricycle having a pair of left and right front wheels and a rear wheel,
A front two wheels characterized in that a steering stem is rotatably supported at a front part of a vehicle body frame, and the pair of left and right front wheels are supported on both sides of a chain type differential unit mounted directly or indirectly on the steering stem. Formula tricycle. The differential units support the front wheels through a pair of left and right arms, respectively, immediately in front of the front fork supported by the steering stem,
2. The front two-wheeled tricycle according to claim 1, wherein the arm is differentially operated in a vertical direction along a pair of linear guide rails arranged in the differential unit.   The chain having a running track in the vertical direction is wound around the inside of the guide rail, and the arm is moved up and down via a pair of sliders connected to both sides of the chain. The described front two-wheeled tricycle.   4. The front two-wheeled tricycle according to claim 3, wherein the chain is mounted in two front and rear in the differential unit and can run in synchronization with each other. 5.   The front two-wheeled tricycle according to claim 3 or 4, wherein an auto tensioner capable of adjusting the tension is mounted at an appropriate position of the chain.   6. The differential unit according to claim 1, wherein the differential unit is connected to and supported by the front fork via a link mechanism, and can be interlocked and followed by a buffering operation of the front fork. Front motorcycle tricycle. The differential unit is configured integrally with the steering stem and supports the front wheels via a pair of left and right arms,
The front two-wheeled tricycle according to claim 1, wherein a front fork is disposed between an upper arm and a lower arm that can turn relative to each other.

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