Motorcycle

A motorcycle with reduced fatigue due to vibrations in travel. A handle bracket is connected to an upper end of a steering shaft through a damper member, and left and right handle bodies are fixed to left and right ends of the handle bracket.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a motorcycle having a front fork journaled by a head pipe of a body frame and a steering handle mounted to an upper end of the front fork.

2. Description of Related Art

A motorcycle has been proposed in which a handle crown is fixed to a steering shaft of a front fork, and a handle divided into separate left and right sections is fixed to left and right ends of the handle crown. See, for example, Chinese Patent Specification No. M245151.

In this motorcycle, because the left and right separate handles are fixed directly to the handle crown, which is fixed to the steering shaft, there is a problem in that vibrations from the engine and body frame are liable to be transmitted to the left and right separate handles. Fatigue due to vibrations in travel is therefore liable to occur.

SUMMARY OF THE INVENTION

The present invention provides a motorcycle with reduced fatigue due to vibrations in travel.

A first embodiment of the invention is a motorcycle comprising a body frame, a front fork journaled by a head pipe of the body frame and journaling a front wheel at a lower end thereof, and a steering handle mounted to an upper end of the front fork. The front fork includes a steering shaft and left and right fork bodies connected to a lower end of the steering shaft through a fork bracket. A handle bracket is connected to an upper end of the steering shaft through a damper member. The steering handle includes separate left and right handle bodies that are fixed to left and right ends of the handle bracket.

With the motorcycle of the first embodiment, since the handle bracket is connected to the steering shaft through the damper member and the handle bodies are fixed to the handle bracket, vibrations from the engine and body frame are absorbed by the damper member and not transmitted to the handle bodies. Fatigue due to vibrations in travel is thereby reduced.

In one implementation, the handle bracket includes a lower bracket fixed to the steering shaft and an upper bracket fixed to the lower bracket through damper members. The left and right handle bodies are fixed to left and right ends of the upper bracket.

According to this implementation, since the lower bracket is fixed to the steering shaft and the damper members are interposed between the lower bracket and the upper bracket, to which the handle bodies are fixed, the lower bracket is surely fixed to the steering shaft. Accordingly, the steering handle is mounted to the body frame with a feeling of stiffness while inhibiting transmission of vibrations. Responsibility at the time of handle manipulation is thereby ensured.

In a further implementation, the damper members are arranged on left and right sides with a portion of the handle bracket fixed to the steering shaft interposed therebetween.

According to the implementation, since the damper members are arranged on left and right sides with a portion of the handle bracket fixed to the steering shaft interposed therebetween, a feeling of stiffness with which the steering handle is supported on the body frame is made further sure. By contrast, if the damper member were arranged on a region where the handle bracket and steering shaft are fixed, the handle bracket would be liable to fluctuate about the fixed region and would decrease the feeling of stiffness of the steering handle on the steering shaft.

In a further implementation, the left and right handle bodies are fixed to the handle bracket by joint bolts.

According to this implementation, since the left and right handle bodies are fixed by joint bolts, the handle bodies are prevented from turning about portions which are fixed to the handle bracket, without the need for structure such as detent pins or the like. By contrast, in other configurations using a front fork having left and right fork bodies extending to an upper end of a steering shaft, in which handle bodies are mounted directly to upper ends of the fork bodies, and in which ring-shaped mount bosses formed on the handle bodies are fitted onto upper ends of the fork bodies and fixed by bolts, there is a need for a detent construction.

In a further implementation, the left and right handle bodies are fixed to left and right ends of the handle bracket with height adjustment spacers therebetween.

According to this implementation, the interposed spacers interpose permit ready adjustment of the handle level to conform to a rider's body.

In a further implementation, a steering-shaft cover is mounted to the upper end of the steering shaft and positioned below the handle bracket. The steering-shaft cover covers harness members extending downwardly of the steering shaft from a car-mount part around the steering handle, and a guide portion is cut out and formed on the steering-shaft cover to hold the harness members in a bundled state.

According to this implementation, the steering-shaft cover also functions as a part for harness bundling to surely guide harness members, and eliminates the need for an exclusive part for harness fixation. By contrast, in a so-called pine-needle type front fork having left and right fork bodies connected to a steering shaft through a fork bracket, there is no part on an upper end of the steering shaft that functions to bundle harness members. Thus, the harnesses are liable to become separated unless an exclusive part for harness fixation is added.

In a further implementation, the handle bracket includes a lower bracket fixed to the steering shaft and an upper bracket fixed to the lower bracket through a damper member by a fixation bolt that is coaxial with the steering shaft.

According to this implementation, since the fixation bolt is coaxial with the steering shaft, the center about which the steering handle fixed to the upper bracket turns agrees with the steering shaft, so that steering manipulation is transmitted to the front wheel without a feeling of physical disorder and maneuverability is improved.

A second embodiment of the invention is a motorcycle comprising a body frame, a front fork journaled by a head pipe of the body frame and journaling a front wheel at a lower end thereof, and a steering handle mounted to an upper end of the front fork. The front fork includes a steering shaft and left and right fork bodies connected to a lower end of the steering shaft through a fork bracket. A handle bracket is connected to an upper end of the steering shaft. The steering handle includes separate left and right handle bodies that are fixed to left and right ends of the handle bracket. A spacing between the fixed portions of the left and right handle bodies is larger than a spacing between the left and right fork bodies.

According to this second embodiment, since the spacing between fixed portions of the left and right handle bodies is larger than the spacing between the left and right fork bodies, the front fork and front wheel can be readily steered without increasing the handle manipulating force on the steering handle too much, and maneuverability is thereby improved.

In one implementation, the handle bracket includes a lower bracket fixed to the steering shaft and an upper bracket fixed to the lower bracket by a fixation bolt that is coaxial with the steering shaft.

According to the implementation, since the fixation bolt is coaxial with the steering shaft, the center about which the steering handle fixed to the upper bracket turns agrees with the steering shaft in the same manner as described above, so that steering manipulation is transmitted to the front wheel without a feeling of physical disorder and maneuverability is improved.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the invention is now described with reference to the drawings.FIGS. 1-17illustrate a motorcycle according to an embodiment of the invention. The front and rear, and left and right directions referred to in the are from the perspective of a rider seated on a seat.

In the drawings, reference numeral1denotes a motorcycle. Motorcycle1comprises an underbone type body frame2, a front wheel3arranged at a front end of body frame2, a rear wheel4arranged at a rear end thereof, an engine5mounted below body frame2, and a saddle-type seat6mounted above body frame2.

Body frame2includes a head pipe7positioned at its front end, a single main frame2aextending rearward and obliquely downward from head pipe7, left and right downtubes2b,2bcontiguous to main frame2aand extending rearward and obliquely downward while diverging outward in a vehicle width direction, left and right seat rails2c,2cextending rearward and obliquely upward from rear ends of downtubes2b,2b, and left and right seat stays2d,2dfor connection of rear ends of seat rails2cand rear ends of downtubes2b.

A rear arm bracket2eextends downward from the rear ends of downtubes2b,2b. A rear arm8is supported on rear arm bracket2ethrough a pivot shaft8ato be able to swing vertically and rear wheel4is journaled at a rear end of rear arm8.

Seat6is mounted on seat rails2cand includes a main seat6a, on which a rider is seated, formed integrally with a tandem seat6b, on which a tandem rider is seated. Seat6opens and closes vertically about a front hinge6c. Arranged below seat6are a battery, a fuel tank and a storage box.

Engine5is a water-cooling type four-stroke engine and is suspended from and supported on downtubes2b. Torque of engine5is transmitted to rear wheel4through a power transmission member such as chain.

Body frame2is covered by a body cover13. Body cover13includes a front cover14, which covers the front of head pipe7, an inner cover17, which covers the rear of head pipe7, a leg shield15, which covers the front of a rider's legs, and a side cover16, which covers a lower periphery of seat6.

A substantially triangular-shaped front lace19is mounted to an upper side of front cover14and a rubber cover18composed of an elastic member is mounted to a rear edge of front lace19. Rubber cover18covers a handle escape hole of a steering handle10provided between front lace19and inner cover17(FIG. 17).

A headlight unit20is arranged on front cover14and a taillight unit21is arranged at a rear end of side cover16.

Motorcycle1comprises a front fork9journaled by head pipe7and journaling front wheel3at a lower end thereof, and steering handle10mounted to an upper end of front fork9.

A meter unit23is provided forwardly of steering handle10and includes a speedometer, a fuel reserve meter and a signal lamp. A meter cover24covers a front portion of meter unit23. A visor24ais formed on meter cover24to lead travel wind above a rider to relieve wind pressure. Visor24ais inclined rearwardly upward to connect to front cover14.

Front fork9is a so-called pine-needle type front fork and includes a steering shaft9aand left and right fork bodies9c,9cconnected and fixed to a lower end of steering shaft9athrough a fork bracket9b. Front wheel3is journaled at lower ends of fork bodies9c,9c, and a front fender22mounted to fork bodies9ccovers an upper portion of front wheel3.

Steering shaft9ais supported through a pair of upper and lower bearings7a,7barranged in head pipe7to enable steering left and right. An upper end9dof steering shaft9aprojects upward from head pipe7(FIG. 2).

Steering handle10is mounted to upper end9dof steering shaft9athrough a handle bracket25. Handle bracket25includes a lower bracket26and an upper bracket27. Lower bracket26is fixed to upper end9dof steering shaft9a, upper bracket27is fixed to lower bracket26, and steering handle10is mounted to upper bracket27.

Steering handle10includes left and right handle bodies11,11. Each handle body11comprises a handle lever11afixed to a base portion11b. Base portions11bare mounted to left and right ends27e,27eof upper bracket27.

Lower bracket26includes a cylinder portion26a, into which upper end9dof steering shaft9ais inserted, a band-shaped bracket body26bfixed to an upper end of cylinder portion26aand diverging forward in a substantially V-shaped manner, and a pair of left and right arm portions26c,26cprojecting forward from bracket body26b. Meter unit23is mounted to left and right arm portions26c.

Cylinder portion26ais formed with a fastening slit26a′ to fix a clamp member26dthereto. Clamp member26dprojects rearward, and a bolt26eis screwed into clamp member26din the vehicle width direction. An engagement recess9e, with which bolt26eengages, is cut out tangentially and formed at a rear edge of steering shaft9a, and lower bracket26is fixed to steering shaft9aby fastening bolt26e(seeFIGS. 6 and 7).

Bracket body26bhas damper mount holes26g,26gformed at its left and right ends. A nut26fis fixed to an underside of a central portion of bracket body26bin the vehicle width direction (FIG. 13).

Upper bracket27is formed by die casting and includes a band-shaped bracket body27adiverging forward in a substantially V-shaped manner. A longitudinal wall portion27bextends downward from a rear edge of bracket body27a. Bracket body27ahas a damper mount hole27cformed in its central portion and handle mount seats27d,27dformed in its left and right ends27e,27e(FIG. 10). Downwardly extending left and right boss portions27f,27fare protrusively formed on an underside of bracket body27aclose to and inwardly of handle mount seats27d,27d.

Handle mount seats27dare substantially egg-shaped and are larger in thickness than the remaining portion of bracket body27a. A pair of bolt holes27g,27gare formed through each mount seat27d, with a spacing in the vehicle width direction, and a positioning recess27hformed therebetween.

Height adjustment spacers35are arranged on mount seats27d(FIG. 8). Projections35aare formed on undersides of spacers35to engage with positioning recesses27h.

Left and right handle bodies11are fixed detachably to left and right handle mount seats27dof upper bracket27by two joint bolts36,36inserted from above with spacers35therebetween. Caps37are mounted to base portions11bto cover joint bolts36.

A steering-shaft cover30is mounted to upper bracket27in a manner to be positioned at upper end9dof steering shaft9abelow upper bracket27(FIGS. 4-6). Steering-shaft cover30includes a cover body30a, which covers the rear of lower bracket26between upper bracket27and inner cover17, and left and right mount pieces30b,30bextending forward from both ends of cover body30a(FIG. 16). Mount pieces30bare bolted and fixed detachably to an underside of upper bracket27and a front edge of cover body30ais bolted and fixed detachably to lower edges27b′ of longitudinal wall portion27bof upper bracket27(FIGS. 6 and 7).

Steering-shaft cover30covers a plurality of harness members (not shown) laid downward along steering shaft9afrom car-mount parts such as switches, operating buttons, etc. around steering handle10. A guide portion30cis cut out and formed on right mount piece30bto hold the harness members in a bundled state (FIGS. 6 and 16).

A central portion of upper bracket27in the vehicle width direction is fixed to lower bracket26with a central damper member28therebetween. Damper member28is formed of an elastic member such as rubber or the like. Central damper member28is fitted into damper mount hole27cof upper bracket27, and a collar28ais inserted into a shaft core of central damper member28. By fastening a fixation bolt29, which is inserted into collar28afrom above, to nut26fof lower bracket26, upper bracket27is fixed to lower bracket26with central damper member28therebetween (FIG. 7).

Fixation bolt29is arranged coaxially with a center line of steering shaft9a. Fixation bolt29also mounts thereto a sealing cap29afor sealing between fixation bolt29and a peripheral edge of damper mount hole27c.

Left and right ends27e,27eof upper bracket27are fixed to lower bracket26with left and right damper members31,31therebetween. Damper members31are formed of elastic members such as rubber or the like, Damper members31are fitted into left and right damper mount holes26gof lower bracket26, and boss portions27fof upper bracket27are inserted axially into damper members31. By fastening left and right fixation bolts32, which are inserted into boss portions27ffrom under, with washer members32atherebetween, left and right ends27e,27eof upper bracket27are fixed to lower bracket26with damper members31therebetween (seeFIG. 9). Handle bodies11are fixed in the vicinity of damper members31.

A spacing W1between inner sides of base portions11bof handle bodies11, which are fixed to upper bracket27(FIG. 5), is larger than a spacing W2between axes a, a of left and right fork bodies9c,9c(FIG. 3).

According to the embodiment, since handle bracket25is connected to steering shaft9awith central damper member28and left and right damper members31,31therebetween, and left and right handle bodies11,11are fixed to handle bracket25, vibrations from engine5and body frame2are absorbed by damper members28and31and are not transmitted to handle bodies11. Fatigue due to vibrations in travel is thereby reduced.

According to the embodiment, since lower bracket26is fixed to steering shaft9a, and damper members28,31are interposed between lower bracket26and upper bracket27, to which handle bodies11are fixed, steering handle10is mounted to body frame2with a feeling of stiffness while inhibiting transmission of vibrations, thereby ensuring responsibility at the time of handle manipulation.

According to the embodiment, because damper members31are arranged on left and right sides, with the portion of handle bracket25that is fixed to steering shaft9atherebetween, a feeling of stiffness with which steering handle10is supported on body frame2is made further sure.

Also, since damper members31are arranged in the vicinity of handle bodies11, vibrations are not transmitted to handle bodies11.

According to the embodiment, since handle bodies11are fixed to upper bracket27by means of two joint bolts36, handle bodies11are prevented from turning about portions thereof that are fixed to upper bracket27without the need for structures such as detent pins or the like. That is, in other configurations using a front fork having left and right fork bodies extending to an upper end of a steering shaft, in which handle bodies are mounted directly to upper ends of the fork bodies, and in which ring-shaped mount bosses formed on the handle bodies are fitted onto upper ends of the fork bodies and fixed by bolts, there is a need for a detent construction.

According to the embodiment, since handle bodies11are fixed to left and right ends27e,27eof upper bracket27with spacers35therebetween, a simple height adjustment of spacers35allows adjustment of the handle level to conform to a rider's body.

According to the embodiment, since steering-shaft cover30is positioned below upper bracket27, steering-shaft cover30covers a plurality of harness members extending downward along steering shaft9afrom car-mount parts around steering handle10, and guide portion30cof steering-shaft cover30holds the harness members in a bundled state, steering-shaft cover30also functions as a part for harness bundling to surely guide harness members and eliminates the need for an exclusive part for harness fixation. By contrast, in a so-called pine-needle type front fork having left and right fork bodies connected to a steering shaft through a fork bracket, there is no part on an upper end of the steering shaft that functions to bundle harness members. Thus, the harnesses are liable to become separated unless an exclusive part for harness fixation is added.

Also, since the spacing W1of the fixed portions of handle bodies11is larger than the spacing W2of left and right fork bodies9c,9c, front fork9and front wheel3can be readily steered without increasing the handle manipulating force that a driver applies on steering handle10too much, so that quick switchback manipulation or the like is made easy and maneuverability on roads having a lot of curves is improved.

Also, since the spacing W1of the portions of handle bodies11fixed to upper bracket27is large in width, upper bracket27and hence handle bracket25can be increased in dimension in the vehicle width direction, thus enabling an interior of handle bracket25or a space therebelow to be utilized as a space in which wire harness and auxiliaries are arranged.

According to the embodiment, damper members28,31prevent or inhibit transmission of vibrations. In order to improve this capability, it is advantageous to make the damper members further soft. If made too soft, however, handle steering force is not efficiently transmitted to a front fork and may decrease maneuverability.

According to the embodiment, since handle bracket25is large in width and handle bodies11are arranged as far outside as possible, the force required for sustaining a rotational moment about the steering shaft can be small, which allows use of softer damper members to improve vibration proof capability.

Also, since fixation bolt29, by which upper bracket27is fixed to steering shaft9athrough lower bracket26, is arranged coaxially with steering shaft9a, the center about which steering handle10fixed to upper bracket27turns agrees with steering shaft9a, so that steering manipulation is transmitted to front wheel3without a feeling of physical disorder and maneuverability is improved.

Furthermore, since fixation bolt29is arranged coaxially with steering shaft9a, the interior of handle bracket25or a space therebelow can be efficiently used as a space in which wire harness and auxiliaries are arranged.

The particular embodiments of the invention described in this document should be considered illustrative, rather than restrictive. Modification to the described embodiments may be made without departing from the spirit of the invention as defined by the following claims.