Patent Publication Number: US-8978809-B2

Title: Saddle-ride vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority under 35 U. S. C. §119 to Japanese Patent Application No. 2013-075295, filed Mar. 29, 2013, entitled “Saddle-Ride-Type Vehicle.” The contents of this application are incorporated herein by reference in their entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a saddle-ride vehicle. 
     2. Discussion of the Background 
     Generally, a steering angle sensor is provided in a lower end portion, on an axis, of a steering shaft. Japanese Unexamined Patent Application Publication No. 2009-184419 discloses an example in which a steering angle sensor is provided in front forks which support a front wheel. Specifically, the front forks include a steering stem which is turnably attached to a head pipe constituting a front end of a vehicle body frame, and a bridge which is attached to a lower end portion of the steering stem. The steering angle sensor is provided at a bottom portion of the bridge. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, a saddle-ride vehicle includes a steering shaft, a head pipe, a main frame, a top bridge and a bottom bridge, an upper end bearing and a lower end bearing, a potentiometer, a bracket, and a thread nut. The steering shaft has a shaft axis. The head pipe supports the steering shaft to be rotatable around the shaft axis. The main frame extends from the head pipe toward a rear side of a vehicle body. The top bridge and the bottom bridge are fixed to upper and lower ends of the steering shaft, respectively. The upper end bearing and the lower end bearing are provided inside the head pipe at upper and lower ends of the head pipe, respectively to support the steering shaft rotatably. The potentiometer includes a cable and is configured to output an electric signal in accordance with a pullout amount of the cable. The bracket is provided in the main frame at a connection portion with the head pipe to support the potentiometer. The thread nut is provided between the upper end bearing and the top bridge to abut on the upper end bearing and is screwed to the steering shaft. The thread nut includes a nut main body part, a plurality of engagement grooves, and a plurality of projection parts. The nut main body part includes a guide part to guide the cable to be wound up. The plurality of engagement grooves are provided in an outer circumference portion to engage with a jig. The plurality of projection parts extend in a radial direction from the nut main body part. Each of the plurality of projection parts includes a cable connecting part via which the cable is connected to the thread nut. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings. 
         FIG. 1  is a right-side view illustrating a state where a steering angle sensor is attached to a saddle-ride-type vehicle according to a present embodiment. 
         FIG. 2  is a cross-sectional view illustrating a positional relation among a head pipe, a steering shaft, and a thread nut. 
         FIG. 3  is a perspective view illustrating an attachment state of the steering angle sensor to the saddle-ride-type vehicle in a partially omitted manner. 
         FIG. 4  is a side view illustrating the attachment state of the steering angle sensor in a partially omitted manner. 
         FIG. 5  is an explanation view illustrating the attachment state of the steering angle sensor, specifically a method of fixing a tip of a cable, in a partially omitted manner. 
         FIG. 6  is an explanation view illustrating a relation among a center line of a vehicle body, an extension line in a tangential direction at one side of a guide part, and an extension direction of the cable, and a relation between a rotation center of the thread nut and a fixed position of the cable. 
         FIG. 7  is a plan view illustrating an example of attached positions of the steering angle sensor, a lap sensor, a section sensor, a GPS sensor, and a gyro sensor. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     The embodiments will now be described with reference to the accompanying drawings, wherein like reference numerals designate corresponding or identical elements throughout the various drawings. 
     Hereinafter, a saddle-ride-type vehicle according to the embodiment of the present invention will be described in detail with reference to the attached drawings. 
       FIG. 1  is a right-side view of a motorcycle  12  (vehicle body) as a saddle-ride-type vehicle according to the present embodiment. Note that, for easy understanding of the embodiment of the present invention, front-rear and up-down directions are described using arrow directions illustrated in  FIG. 1  as the reference as long as any special instruction is given, and left-right directions are described using a direction seen from a vehicle driver seated in a vehicle body as the reference. 
     The motorcycle  12  includes, as illustrated in  FIG. 1 , a vehicle body frame  14  which constitutes a vehicle body, and the vehicle body frame  14  includes a head pipe  16  which is provided at a front end thereof, a main frame  18  which extends rearward and slant downward from the head pipe  16 , a pivot plate  20  which is connected to a rear end portion of the main frame  18 , a seat frame  22  which is connected to an intermediate portion of the main frame  18  and extends rearward and upward, and a down frame  24  which extends rearward and downward from the head pipe  16 , below the main frame  18 . An engine  26  and a transmission  28  which is integrally attached to a rear portion of the engine  26  are attached to the main frame  18 , the pivot plate  20 , and the down frame  24 . Moreover, the motorcycle  12  is attached with a rear cowl  29  which extends rearward together with the seat frame  22  and covers both side surfaces and a lower surface of the seat frame  22 . 
     The engine  26  is a single cylinder engine, and includes a crankcase  30 , a cylinder block  32  which is attached to a front upper portion of the crankcase  30 , a cylinder head  34  which is attached to an upper end portion of the cylinder block  32 , and a cylinder head cover  36  which covers an upper opening of the cylinder head  34 . The cylinder head  34  is connected with a muffler  40  via an exhaust pipe  38 . 
     Moreover, the motorcycle  12  includes a steering shaft  42  which is supported in the head pipe  16 , a pair of front forks  44  which are disposed in left and right sides of the head pipe  16  being separated from each other, a top bridge  46  which connects respective upper portions of the pair of front forks  44 , and a bottom bridge  48  which connects respective central portions of the pair of front forks  44 . 
     The steering shaft  42  is supported rotationally movable relative to the head pipe  16  by an upper end bearing  50  and a lower end bearing  52  which are respectively fixed an upper end portion and a lower end portion of the head pipe  16 , as illustrated in  FIG. 2 . Moreover, an upper end portion and a lower end portion of the steering shaft  42  are respectively fixed to the top bridge  46  and the bottom bridge  48 . In addition, a thread nut  54  which abuts on the upper end bearing  50  and is screwed to the steering shaft  42  is included between the upper end bearing  50  and the top bridge  46 . A lower surface of the lower end bearing  52  is abutted on the bottom bridge  48 . Accordingly, tightening the thread nut  54  allows loads to the upper end bearing  50  and the lower end bearing  52  to be adjusted. Note that, a nut  58  is screwed into a groove  56  formed on the upper portion of the steering shaft  42  which protrudes from an upper surface of the top bridge  46 . 
     The motorcycle  12  includes, as illustrated in  FIG. 1 , a front wheel  60  as a steering wheel which is pivotally supported by the pair of left and right front forks  44  in a rotatable manner, a handle  64  (steering) which is fixed to an upper portion of the top bridge  46  via a pair of fixing members  62 , a pair of left and right swing arms  66  which are supported by the pivot plate  20  in a swingable manner, and a rear wheel  68  which is pivotally supported by rear end portions of the pair of left and right swing arms  66  in a rotatable manner. A front fender  70  is attached to a position above and away from the front wheel  60 . A front cover  72  which covers the head pipe  16  and the like is attached to an upper portion of the front fender  70 . A fuel tank  74  is provided above the engine  26 . A seat  76  is disposed on the rear of the fuel tank  74 . 
     Further, as illustrated in  FIG. 3  and  FIG. 4 , the saddle-ride-type vehicle according to the present embodiment is devised so as to attach a steering angle sensor  90  to the thread nut  54 . 
     Firstly, the steering angle sensor  90  includes a potentiometer  100 , and the potentiometer  100  outputs an electric signal (voltage signal, current signal) at a level in accordance with the pullout amount of a cable  102 . The cable  102  is always urged in a direction of a housing  104  by a spring member installed in the housing  104 . 
     Generally, the thread nut  54  includes a nut main body part  106  which is screwed to the steering shaft  42 , multiple engagement grooves  108  (see  FIG. 6 ) for engaging a jig which are formed in an outer circumference portion of the nut main body part  106 , and multiple projection parts  110  which extend in the radial direction from an upper portion of the nut main body part  106 . Accordingly, the thread nut  54  has a petal-like shape in a top view. 
     Therefore, in the present embodiment, provided is a flange part  112  which extends in the radial direction from a bottom portion of the nut main body part  106  and abuts on the upper end bearing  50 . Further, each of the projection parts  110  is provided with a through-hole  116  into which a screw  114  is inserted. In the nut main body part  106 , a small-diameter portion sandwiched between the flange part  112  and the multiple projection parts  110  functions as a guide part  118  around which the cable  102  is wound up. 
     Meanwhile, as illustrated in  FIG. 5 , a ring member  120  into which the screw  114  is inserted is fixed to an end portion of the cable  102  extended from the potentiometer  100 . Accordingly, a tip of the cable  102  can be fixed to the thread nut  54  such that the end portion of the cable  102  is positioned to one arbitrarily projection part  110  selected among the multiple projection parts  110 , and in such a state, the screw  114  is screwed into the flange part  112  through the through-hole  116  of the selected projection part  110  and the ring member  120  of the cable  102 . In other words, each of the through-holes  116  of the multiple projection parts  110  provided in the thread nut  54  functions as a cable fixing part. 
     In addition, a bracket  122  for fixing the potentiometer  100  is fastened to the motorcycle  12 . The bracket  122  is formed, as illustrated in  FIG. 4 , such that a plate member made of a metal is bent, for example, and is fastened to the main frame  18  at a portion downwardly slanted from a connection portion with the head pipe  16  toward the rear side. In other words, the bracket  122  integrally includes a plate-shaped fixing part  128  which is fastened to the main frame  18  by being screwed together with a tank support part  126  by a bolt  124 , a plate-shaped extension part  130  which extends from the fixing part  128  toward an upper end of the head pipe  16 , and a plate-shaped side plate part  132  which stands upright from a side portion of the extension part  130 . The potentiometer  100  is removably supported on a right side surface of the side plate part  132 . Moreover, a protection cover member  134  for protecting the cable  102  pulled out from the potentiometer  100  is rotatably attached to a left side surface of the side plate part  132 . The protection cover member  134  covers the cable  102  from one side to the other side over the cable  102 . 
     In this manner, with the saddle-ride-type vehicle according to the present embodiment, the rotational movement (steering angle) of the handle  64  can be measured by simply preparing the thread nut  54  with the projection parts  110  and the nut main body part  106  which are processed, and attaching the potentiometer  100  which is removably supported on a vehicle body thereto. In other words, no dedicated part is necessary to be provided on the steering shaft  42 , only a small change is required even in a case of a design change of the potentiometer  100 , and the potentiometer  100  is easy to be installed as an external device, thereby making it possible to suppress an increase in the cost and an increase in the number of parts. 
     When only one projection part  110  among the multiple projection parts  110  provided in the thread nut  54  is functioned as the cable fixing part, fastening the thread nut  54  results in change of an attached position of the cable  102 . In contrast, in the present embodiment, each of the multiple projection parts  110  can function as the cable fixing part to allow the attached position to be selected. Accordingly, versatility can be achieved. In this case, the projection parts  110  are disposed at equal intervals to allow the tip of the cable  102  to be easily fixed to a position in accordance with the length of the cable  102 . 
     Moreover, the thread nut  54  includes the multiple projection parts  110  which extend in the radial direction from the upper portion of the nut main body part  106 , and the flange part  112  which extends in the radial direction from the bottom portion the nut main body part  106 . Accordingly, the multiple projection parts  110  and the flange part  112  can constitute the guide part  118  which guides winding up of the cable  102 . In other words, the guide part  118  is not necessary to be provided as a separate member because the multiple projection parts  110  are also used as members for constituting the guide part  118 , thereby making it possible to suppress an increase in the number of parts. 
     The cable  102  pulled out from the potentiometer  100  is always urged in the direction of the housing  104  by the spring member installed in the housing  104 . In other words, the cable  102  is wound up by the spring member. Therefore, the potentiometer  100  can measure a steering angle by following the rotational movement of the handle  64 . 
     Moreover, in the present embodiment, the bracket  122  to which the potentiometer  100  is fixed is fixed to the main frame  18  by being screwed together with the tank support part  126  by the bolt  124 . In this case, the potentiometer  100  is attached to the main frame  18  using the tank support part  126 . This enables the potentiometer  100  to be held without requiring a redundant attachment part. 
     Here, a preferable attachment method of the potentiometer  100  will be described also with reference to FIG. 
       6 . 
     Firstly, the potentiometer  100  is preferably attached to the bracket  122  (see  FIG. 4 ) such that the cable  102  is positioned so as to extend in parallel with a center line La of the vehicle body in both cases in a top view and in a side view, as illustrated in  FIG. 6 . Specifically, as illustrated in  FIG. 6 , the cable  102  extended from the potentiometer  100  is positioned on an extension line Lb in a tangential direction at one side (right side) of the guide part  118  in a top view. In addition, as illustrated in  FIG. 4 , the cable  102  extended from the potentiometer  100  is positioned so as to be in parallel with an extension line Lc (extension line indicating the same height) of the guide part  118  of the thread nut  54  in a side view. 
     This allows a tension (pullout) of the cable  102  from the potentiometer  100  and a return thereof to the potentiometer  100  to easily follow the rotational movement of the handle  64 , thereby making it possible to implement a low friction with respect to the tension or the return of the cable  102 . 
     Moreover, the potentiometer  100  is disposed, as illustrated in  FIG. 6 , at one side (for example, right side) relative to the center line La of the vehicle body, and the handle  64  is in a straight ahead state (position at which the front wheel  60  directs forward), the cable  102  is fixed to the other side (for example, left side) relative to the center line La through the front side of the thread nut  54 . This allows the pullout or the return of the cable  102  to easily follow the rotational movement in both directions of the handle  64 , thereby making it possible to detect the steering angle with high accuracy. 
     Moreover, when only one projection part  110  among the multiple projection parts  110  provided in the thread nut  54  is functioned as the cable fixing part, fastening the thread nut  54  results in change of an attached position of the cable  102 . In contrast, in the present embodiment, the through-holes  116  are respectively provided in the multiple projection parts  110  (all the projection parts  110  in  FIG. 6 ) to cause the multiple projection parts  110  to function as the cable fixing parts. In addition to a projection part  110  located at a “A” position of  FIG. 6 , for example, a projection part  110  (a projection part  110  located at a “B” position or a projection part  110  located at a “C” position) located before and after the projection part  110  located at the “A” position or the like can be also selected as the attached position. Accordingly, versatility can be achieved. 
     In addition, in the present embodiment, the potentiometer  100  is attached such that when the handle  64  is fully turned to one side (for example, right side) relative to the center line La of the vehicle body, the projection part  110  which supports the cable  102  is not positioned at least at the one side across the center line La of the vehicle body. This allows the cable  102  to always come into contact with the guide part  118  in the entire movable range of the potentiometer  100  (range of the cable being pulled out and returned), thereby enabling the cable  102  to smoothly be pulled out and returned using the guide part  118 . 
     Note that, as illustrated in  FIG. 6 , when the potentiometer  100  is installed in a position at the right side of a vehicle body, only the multiple projection parts  110  positioned at the left side may respectively function as the cable fixing parts. Needless to say, all the projection parts  110  are functioned as the cable fixing parts to allow the potentiometer  100  to be installed at the left side as well as the right side, of the vehicle body. Accordingly, versatility can be achieved. 
     In the foregoing, although the attachment method of the steering angle sensor  90  is explained, various kinds of sensors as well as the steering angle sensor  90  may be attached to the motorcycle  12 . 
     For example, as illustrated in  FIG. 3  and  FIG. 7 , a lap sensor  142  (sensor which measures a lap time) and a section sensor  144 , in addition to the potentiometer  100 , are attached to the bracket  122  to which the potentiometer  100  is fixed. For example, the bracket  122  is provided with a left-side attachment part  146   a  and a right-side attachment part  146   b  which respectively extend in left and right sides from the portion thereof fixed to the tank support part  126 . For example, the lap sensor  142  is fixed to the left-side attachment part  146   a,  and the section sensor  144  is fixed to the right-side attachment part  146   b.  Accordingly, the bracket  122  which supports the steering angle sensor  90  is commonly used for the various sensors, thereby making it possible to suppress an increase in the cost and an increase in the number of parts. 
     Moreover, as illustrated in  FIG. 3  and  FIG. 7 , a GPS sensor  152  may be provided on an attachment bar  150  which is rotatably stretched on an upper portion of a handle bar  148 . A tubular cushion  154  is generally attached to the attachment bar  150 , to cause the GPS sensor  152  to be hidden in the cushion  154 . 
     In addition, as illustrated in  FIG. 7 , a gyro sensor  158  may be attached to a seat support stay  156  which supports and fixes the seat  76  (see  FIG. 1 ). The seat support stay  156  is installed in a position at a nearly central portion of the vehicle body. Therefore, the gyro sensor  158  can detect the inclination with high accuracy during when the vehicle body is traveling. 
     Note that, the saddle-ride-type vehicle according to the embodiment of the present invention is not limited to the abovementioned embodiment, and is apparently able to employ various configurations without departing from the gist of the present invention. 
     The embodiment of the present invention involves the following aspects. 
     A first aspect of the embodiment of the present invention provides a saddle-ride-type vehicle including: a steering shaft ( 42 ); a head pipe ( 16 ) which supports the steering shaft ( 42 ) in a rotationally movable manner; a main frame ( 18 ) which extends from the head pipe ( 16 ) toward a rear side of a vehicle body ( 12 ); a top bridge ( 46 ) and a bottom bridge ( 48 ) which are respectively fixed to upper and lower ends of the steering shaft ( 42 ); an upper end bearing ( 50 ) and a lower end bearing ( 52 ) which support the steering shaft ( 42 ) in a rotationally movable manner inside upper and lower ends of the head pipe ( 16 ); and a thread nut ( 54 ) which abuts on the upper end bearing ( 50 ), is positioned between the upper end bearing ( 50 ) and the top bridge ( 46 ), and is screwed to the steering shaft ( 42 ), the thread nut ( 54 ) including a plurality of engagement grooves ( 108 ) for engaging a jig which are formed in an outer circumference portion thereof, and a plurality of projection parts ( 110 ) which extend in a radial direction from a nut main body part ( 106 ), in which the saddle-ride-type vehicle includes a bracket ( 122 ) which is provided in the main frame ( 18 ) at a connection portion with the head pipe ( 16 ), and removably fastens a potentiometer ( 100 ) for outputting an electric signal at a level in accordance with a pullout amount of a cable ( 102 ), each of the projection parts ( 110 ) of the thread nut ( 54 ) includes a cable fixing part which fixes the cable ( 102 ) extended from the potentiometer ( 100 ), and the nut main body part ( 106 ) of the thread nut ( 54 ) includes a guide part ( 118 ) which guides winding up of the cable ( 102 ). 
     A second aspect of the embodiment of the present invention provides the saddle-ride-type vehicle in which the projection parts ( 110 ) of the thread nut ( 54 ) extend in the radial direction from an upper portion of the nut main body part ( 106 ), the thread nut ( 54 ) further includes a flange part ( 112 ) which extends in the radial direction from a bottom portion of the nut main body part ( 106 ), and the projection parts ( 110 ) and the flange part ( 112 ) constitute the guide part ( 118 ). 
     A third aspect of the embodiment of the present invention provides the saddle-ride-type vehicle in which the potentiometer ( 100 ) is a winding-up type, and winds up the cable ( 102 ) by an urged force. 
     A fourth aspect of the embodiment of the present invention provides the saddle-ride-type vehicle in which the potentiometer ( 100 ) is disposed such that the cable ( 102 ) extends in parallel with a center line (La) of the vehicle body ( 12 ), is positioned on an extension line (Lb) in a tangential direction at one side of the guide part ( 118 ) in a top view, and is in parallel with an extension line (Lc) of the guide part ( 118 ) of the thread nut ( 54 ) in a side view. 
     A fifth of the embodiment of the present invention aspect provides the saddle-ride-type vehicle in which the potentiometer ( 100 ) is disposed at one side of the center line (La) of the vehicle body ( 12 ), and the cable ( 102 ) is fixed to the other side of the center line (La) through a front side of the thread nut ( 54 ) when a steering ( 64 ) is in a straight ahead state. 
     A sixth aspect of the embodiment of the present invention provides the saddle-ride-type vehicle in which the potentiometer ( 100 ) is attached such that when the steering ( 64 ) is fully turned to the one side of the center line (La) of the vehicle body ( 12 ), a fixed position of the cable ( 102 ) is not positioned at least at the one side across the center line (La) of the vehicle body ( 12 ). 
     A seventh aspect of the embodiment of the present invention provides the saddle-ride-type vehicle in which a cover member ( 134 ) which protects the cable ( 102 ) is supported by the bracket ( 122 ) which holds the potentiometer ( 100 ). 
     An eighth aspect of the embodiment of the present invention provides the saddle-ride-type vehicle in which the bracket ( 122 ) which holds the potentiometer ( 100 ) is fixed to the main frame ( 18 ) by being screwed together with a tank support part ( 126 ). 
     According to the first aspect of the embodiment of the present invention, the rotational movement (steering angle) of the handle can be measured by simply preparing the thread nut with the projection parts and the nut main body part which are processed, and attaching the potentiometer which is removably supported on a vehicle body thereto. In other words, no dedicated part is necessary to be provided on the steering shaft, only a small change is required even in a case of a design change of the potentiometer, and the potentiometer is easy to be installed as an external device, thereby making it possible to suppress an increase in the cost and an increase in the number of parts. 
     In addition, each of the multiple projection parts provided in the thread nut functions as the cable fixing part to allow an attached position of the cable of the potentiometer to be selected regardless of the individual difference in length thereof. Accordingly, versatility can be achieved. 
     According to the second aspect of the embodiment of the present invention, the guide part which guides winding up of the cable can be configured with a simple structure. 
     According to the third aspect of the embodiment of the present invention, the potentiometer of a winding-up type can measure a steering angle by following the rotational movement. 
     According to the fourth aspect of the embodiment of the present invention, a tension (pullout) of the cable from the potentiometer and a return thereof to the potentiometer are easy to follow the rotational movement of the steering, thereby making it possible to implement a low friction with respect to the tension or the return of the cable. 
     According to the fifth aspect of the embodiment of the present invention, the pullout or the return of the cable are easy to follow the rotational movement in both directions of the steering, thereby making it possible to detect the steering angle with high accuracy. 
     According to the sixth aspect of the embodiment of the present invention, the cable is allowed to always come into contact with the guide part in the entire movable range of the potentiometer (range of the cable being pulled out and returned), thereby enabling the cable to smoothly be pulled out and returned using the guide part. 
     According to the seventh aspect of the embodiment of the present invention, protection of the cable can be implemented although the cover member is retrofitted. 
     According to the eighth aspect of the embodiment of the present invention, the potentiometer is attached to the main frame using the tank support part. This enables the potentiometer to be held without requiring a redundant attachment part. 
     Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.