Patent Description:
As a shift device for a straddle-type vehicle, there is known a shift device employing a quick shift that can detect a shift operation by a driver and perform a shift change without performing a clutch operation (for example, see Patent Literature <NUM>). In the shift device described in Patent Literature <NUM>, one end of a shift shaft protrudes from an upper side surface of a crankcase, and a shift lever extends rearward from a lower side surface of the crankcase. An upper end of a shift rod is coupled to one end of the shift shaft via a link arm, and a lower end of the shift rod is coupled to an intermediate position of the shift lever. A shift sensor is integrally provided on the shift rod that is long in an upper-lower direction, and a shift operation in accordance with an operation load applying to the shift rod is detected. Patent Literature <NUM> discloses a shift device for a motorcycle, the shift device having a sensor unit. The shift device translates a linear movement of a shift rod into a rotational movement which is detected by the sensor unit, a housing and a connecting element being provided for implementing the movement, the housing and the connecting element being connected by at least a spring element. <CIT>, on which the two-part form is based, discloses a control device for a motorcycle including a transmission that allows switching between a neutral state and a number of engaged shift positions, a shift control section that controls a shift state of the transmission, and an N/D changeover switch that switches between the neutral state and a drive mode for executing automatic shift among the plural shift positions. The shift control device also includes a hand-operated shift switch that allows manual shifting among the plural shift positions, and a foot operated shift control unit that allows manual shifting among the plural shift positions during the drive mode according to an operation of a shift pedal.

In order to provide the shift sensor integrally with the shift rod, it is necessary to ensure a sufficient length of the shift rod. Therefore, it is difficult to provide the shift sensor depending on a layout of the straddle-type vehicle.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a compact shift device in which a shift sensor can be disposed even in a layout in which a sufficient length of a shift rod cannot be ensured.

There is provided a shift device for a straddle-type vehicle that is configured to cause a transmission device to perform a shift change in accordance with rotation of a shift shaft. The shift device is defined in claim <NUM>. Preferred features are defined in the dependent claims.

In the shift device according to an aspect of the present invention, the shift sensor has a function of detecting the shift operation, and the shift sensor functions as a link arm that couples the shift shaft and the shift rod. Even in a layout in which a sufficient length of the shift rod cannot be ensured, the shift sensor can be provided in the shift device. Since the shift sensor and the operation portion are positioned at the same side in a manner of sandwiching the shift rod in a vehicle front view, the shift lever and the shift rod are disposed in a compact manner in the same space, and the shift device is reduced in size. In addition, since the shift sensor is provided instead of a link arm, the number of components is suppressed from increasing, and the shift sensor is easily attached.

A shift device according to the present invention causes a transmission device to perform a shift change in accordance with rotation of a shift shaft of a straddle-type vehicle. The shift lever is provided with an operation portion that receives a shift operation, a shift sensor is provided on the shift shaft so as to be integrally rotatable with the shift shaft, and the shift lever and the shift sensor are coupled to each other via a shift rod. The shift sensor detects a shift operation on the shift lever in accordance with a movement of the shift rod. The shift sensor has a function of detecting the shift operation, and the shift sensor functions as a link arm that couples the shift shaft and the shift rod. Even in a layout in which a sufficient length of the shift rod cannot be ensured, the shift sensor can be provided in the shift device. Since the operation portion and the shift sensor are positioned at the same side in a manner of sandwiching the shift rod in a vehicle front view, the shift lever and the shift rod are disposed in a compact manner in the same space, and the shift device is reduced in size. In addition, since the shift sensor is provided instead of a link arm, the number of components is suppressed from increasing, and the shift sensor is easily attached.

Hereinafter, a present embodiment, representing an embodiment of the present invention, will be described in detail with reference to the accompanying drawings. <FIG> is a left side view showing a straddle-type vehicle with a shift device according to the present embodiment. <FIG> is a left side view showing a shift device according to a comparative example, not encompassed by the wording of the claims. In the following drawings, an arrow FR indicates a vehicle front side, an arrow RE indicates a vehicle rear side, an arrow L indicates a vehicle left side, and an arrow R indicates a vehicle right side.

As shown in <FIG>, a straddle-type vehicle <NUM> is configured by mounting various components such as an engine <NUM> and an electrical system on a twin spar type vehicle body frame <NUM> formed by aluminum casting. The vehicle body frame <NUM> includes a pair of main frames <NUM> that are branched off from a head pipe <NUM> to the left and right and extend rearward, and a pair of down frames <NUM> that are branched off from the head pipe <NUM> to the left and right and extend downward. A rear portion of the engine <NUM> is supported by the pair of main frames <NUM>, and a front portion of the engine <NUM> is supported by the pair of down frames <NUM>. Since the engine <NUM> is supported by the vehicle body frame <NUM>, rigidity of the entire vehicle is ensured.

A front portion of the main frame <NUM> serves as a tank rail <NUM> located above the engine <NUM>, and a fuel tank <NUM> is supported by the tank rail <NUM>. A rear portion of the main frame <NUM> serves as a body frame <NUM> located at a rear side of the engine <NUM>, and a swing arm <NUM> is swingably supported at a substantially intermediate position in an upper-lower direction of the body frame <NUM>. The swing arm <NUM> is coupled to an upper portion of the body frame <NUM> via a link plate <NUM> and a rear suspension <NUM>. A seat rail <NUM> and a back stay <NUM> extend rearward from the upper portion of the body frame <NUM>, and a rider seat <NUM> is supported on the seat rail <NUM>.

A pair of front forks <NUM> are supported by the head pipe <NUM>, and a front wheel <NUM> is rotatably supported by lower ends of the front forks <NUM>. The swing arm <NUM> extends rearward from the body frame <NUM>, and a rear wheel <NUM> is rotatably supported by a rear end of the swing arm <NUM>. The engine <NUM> is coupled to the rear wheel <NUM> via a chain drive type transmission mechanism, and power of the engine <NUM> is transmitted to the rear wheel <NUM> via the transmission mechanism. Footrests <NUM> are provided on the body frame <NUM> via footrest brackets <NUM>. A shift device <NUM> is provided between a lower portion of the engine <NUM> and the left footrest <NUM>.

As shown in the comparative example in <FIG>, when three major axes of the engine are arranged in a triangular shape, an arrangement space of a shift device <NUM> can be ensured in a height direction. In such an engine, a shift sensor <NUM> can be attached to a shift rod <NUM> by ensuring a length of the shift rod <NUM> of the shift device <NUM> in a vertical direction. A shift lever <NUM> is coupled to a lower end of the shift rod <NUM>, and a shift shaft <NUM> is coupled to an upper end of the shift rod <NUM> via a link arm <NUM>. A shift operation of the shift lever <NUM> is transmitted to the shift shaft <NUM>, and the shift shaft <NUM> is rotated to cause the transmission mechanism to perform a shift change.

In the engine <NUM> according to <FIG>, since the three major axes are arranged in a front-rear direction, a shift rod <NUM> of the shift device <NUM> cannot be directed vertically, and a sufficient length cannot be ensured (see <FIG>). The body frame <NUM> is positioned at a rear side of the engine <NUM>, and the shift rod <NUM> needs to extend rearward in order to attach a shift sensor on the shift rod <NUM>. When the shift rod <NUM> is extended, the entire shift device <NUM> is increased in size, and it is difficult to ensure a minimum ground clearance, a bank angle, and the like. Therefore, the shift rod <NUM> is shortened by using a shift sensor <NUM> having a link arm shape in the present embodiment, and miniaturization is achieved by a concentrated arrangement of respective members of the shift device <NUM>.

A shift device according to the present invention will be described with reference to <FIG> and <FIG>. <FIG> is a left side view showing a periphery of the engine and a shift device according to the present embodiment. <FIG> is a bottom view showing a periphery of the engine and a shift device according to the present embodiment. <FIG> and <FIG> show a state where a sprocket cover is removed from the engine.

As shown in <FIG> and <FIG>, the engine <NUM> includes a crankcase <NUM> having an upper-lower divided structure that includes an upper case <NUM> and a lower case <NUM>. The upper case <NUM> is integrated with a cylinder, and a cylinder head <NUM> and a cylinder head cover (not shown) are attached to an upper portion of the upper case <NUM>. A valve gear (not shown) for operating intake and exhaust valves is accommodated inside the cylinder head <NUM> and the cylinder head cover. An oil pan <NUM> that stores oil for lubrication and cooling is attached to a lower portion of the lower case <NUM>. A magneto cover <NUM> that covers a magneto (not shown) from a side is attached to a left side surface of the crankcase <NUM>.

A crankshaft <NUM> is disposed inside the magneto cover <NUM>, and a counter shaft <NUM> and a drive shaft <NUM> are disposed in parallel with the crankshaft <NUM> at a rear side of the crankshaft <NUM>. In this manner, the crankshaft <NUM>, the counter shaft <NUM>, and the drive shaft <NUM> are arranged side by side in the front-rear direction. A water pump <NUM> is disposed below the counter shaft <NUM>, and a shift cam <NUM> is disposed below the drive shaft <NUM> in parallel with the drive shaft <NUM>. Further, a shift shaft <NUM> is disposed at a rear side of the shift cam <NUM> in parallel with the shift cam <NUM>, and the shift sensor <NUM> is attached to one end of a shift shaft <NUM> protruding from a left side surface of the lower case <NUM> so as to be integrally rotatable with the shift shaft <NUM>.

The shift sensor <NUM> is disposed below the drive shaft <NUM> and is disposed between the water pump <NUM> and the body frame <NUM>. The shift sensor <NUM> is positioned above a lower end of the water pump <NUM> and is positioned inside the magneto cover <NUM> in a vehicle width direction (particularly, see <FIG>). Since the water pump <NUM> is disposed in a manner of covering the shift sensor <NUM> from the front side, the shift sensor <NUM> is effectively protected by the water pump <NUM> from flying objects such as flying stones from the front side. A lead wire <NUM> extends obliquely upward from a front surface of the shift sensor <NUM>, and the lead wire <NUM> is not entangled with an operation portion <NUM> of a shift lever <NUM> at a rear side of the shift sensor <NUM>.

The footrest bracket <NUM> is attached to a rear edge of the body frame <NUM>, and the shift lever <NUM> is attached to the footrest bracket <NUM> in a manner of being coaxial with the footrest <NUM>. The shift lever <NUM> is formed with a long arm <NUM> and a short arm <NUM> so as to be a substantially L shape in a side view. An attachment portion <NUM> (see <FIG>) that is swingably supported by the footrest bracket <NUM> is formed at a bent portion of the shift lever <NUM>. The long arm <NUM> extends obliquely downward toward a front side from the attachment portion <NUM>, and the operation portion <NUM> that receives a shift operation is provided at a tip end of the long arm <NUM>. A tip end side of the long arm <NUM> overlaps with the body frame <NUM> in a vehicle side view.

The short arm <NUM> extends substantially downward from the attachment portion <NUM>, and a rear end of the shift rod <NUM> is coupled to a tip end of the short arm <NUM> via a joint <NUM>. The shift rod <NUM> extends obliquely upward toward the front side from the joint <NUM> and crosses an outer side of the body frame <NUM> in the vehicle width direction. An upper portion of the shift sensor <NUM> is coupled to a front end of the shift rod <NUM> via a joint <NUM>. The shift sensor <NUM>, the shift lever <NUM>, and the shift rod <NUM> are positioned below the drive shaft <NUM> and the swing arm <NUM> and above the lower end of the water pump <NUM>. In this manner, respective members of the shift device <NUM> are disposed in a compact manner at a vehicle lower side.

In the shift device <NUM>, when the shift lever <NUM> is operated by a driver, the shift shaft <NUM> is integrally rotated by a predetermined angle with the shift sensor <NUM> via the shift rod <NUM>. The rotation of the shift shaft <NUM> is transmitted to the shift cam <NUM>, and the shift cam <NUM> is rotated by a predetermined angle, so that a shift fork (not shown) changes a combination of transmission gears of the counter shaft <NUM> and the drive shaft <NUM> so as to perform a shift change. At this time, a shift operation on the shift lever <NUM> in accordance with a movement of the shift rod <NUM> is detected by the shift sensor <NUM>, and the shift change can be performed without performing a clutch operation.

A shift device according to the present invention will be described with reference to <FIG>. <FIG> is a left side view showing the shift device according to the present embodiment. <FIG> is a right side view showing the shift device according to the present embodiment. <FIG> is a front view showing the shift shaft according to the present embodiment.

As shown in <FIG> and <FIG>, the shift device <NUM> includes the shift sensor <NUM> that detects a shift operation on the shift lever <NUM>. A sensor main body <NUM> of the shift sensor <NUM> is formed into a triangular shape with rounded corners in a side view. A Hall integrated circuit (IC) <NUM> serving as a detection portion is provided on an outer side surface <NUM> at an outer side in the vehicle width direction of the sensor main body <NUM>, and a pair of protection portions <NUM> and <NUM> are provided in a manner of sandwiching the Hall IC <NUM> from above and below. The Hall IC <NUM> detects a movement of the shift rod <NUM> in accordance with the shift operation on the shift lever <NUM>. The lead wire <NUM> extends from a front end of the Hall IC <NUM> toward a control device (not shown).

The pair of protection portions <NUM> and <NUM> protect the Hall IC <NUM> from external forces from above and below. The Hall IC <NUM> protrudes outward in the vehicle width direction from the outer side surface <NUM> of the sensor main body <NUM>, and the pair of protection portions <NUM> and <NUM> are increased in protruding amounts from an upper portion and a lower portion of the sensor main body <NUM> toward an outer side in the vehicle width direction as coming close to the Hall IC <NUM>. That is, an outer surface of the upper protection portion <NUM> is inclined downward toward the outer side in the vehicle width direction, and an outer surface of the lower protection portion <NUM> is inclined upward toward the outer side in the vehicle width direction. Even when an external force is applied to the protection portions <NUM> and <NUM> from above or below by a foot of a driver, the external force is deflected outward in the vehicle width direction, and the Hall IC <NUM> is effectively protected.

As shown in <FIG> and <FIG>, a holding portion <NUM> that holds the shift shaft <NUM> and a fastening boss <NUM> that is continuous with a front side of the holding portion <NUM> are provided at an inner side of the sensor main body <NUM> in the vehicle width direction in an inner side surface view. An opening is formed in the holding portion <NUM> at a substantially central position of the sensor main body <NUM> in a vehicle side view, and a female serration <NUM> is attached to the opening. A slit <NUM> is formed so as to divide the fastening boss <NUM> from a fitting hole of the female serration <NUM> toward an outer side in a radial direction. With a straight line S on the slit <NUM> interposed therebetween, lower portion of the holding portion <NUM> and the fastening boss <NUM> is coupled to an inner side surface <NUM> of the sensor main body <NUM>, and upper portion of the holding portion <NUM> and the fastening boss <NUM> is separated from the inner side surface <NUM> of the sensor main body <NUM>.

A male serration of the shift shaft <NUM> is inserted into the female serration <NUM>, and a tip end of the shift shaft <NUM> is brought into contact with a contact surface <NUM> of the sensor main body <NUM> so as to position the shift shaft <NUM>. The contact surface <NUM> of the sensor main body <NUM> is one step higher than the inner side surface <NUM> of the sensor main body <NUM>. The fastening boss <NUM> extends to a lower end of the sensor main body <NUM>, and a bolt <NUM> is fastened to the fastening boss <NUM> from a lower side of the fastening boss <NUM>. When the bolt <NUM> is fastened to the fastening boss <NUM>, a slit width is narrowed, and the shift shaft <NUM> is held by the female serration <NUM> of the holding portion <NUM>. Accordingly, the shift sensor <NUM> is attached to the shift shaft <NUM> so as to be integrally rotatable with the shift shaft <NUM>.

Since the bolt <NUM> is fastened from a lower side of the vehicle by a tool, a tool line is ensured without affecting a layout of other components such as the water pump <NUM>. In a non-operated state of the shift device <NUM> (the shift lever <NUM>), the shift sensor <NUM> is inclined such that a front side of a lower end of the shift sensor <NUM> is positioned above a rear side thereof. That is, the shift sensor <NUM> is slightly inclined rearward about the shift shaft <NUM>. As described above, since the fastening boss <NUM> is formed at a front side of the shift sensor <NUM>, it is easy to see a head portion of the bolt <NUM> from the front side, and the bolt <NUM> is easily fastened to the fastening boss <NUM>.

The front end of the shift rod <NUM> is coupled to the upper portion of the sensor main body <NUM> via the joint <NUM>. In this manner, the shift shaft <NUM> is held at a substantially central portion of the sensor main body <NUM>, and the shift rod <NUM> is coupled to the upper portion of the sensor main body <NUM>, so that the sensor main body <NUM> functions as a link arm that couples the shift shaft <NUM> and the shift rod <NUM>. Since the shift sensor <NUM> is not provided on the shift rod <NUM>, it is not necessary to ensure a long shift rod <NUM> in order to attach the shift sensor <NUM>. Since the shift sensor <NUM> is used instead of a link arm, the number of components is suppressed from increasing, and the shift sensor <NUM> is easily attached.

As shown in <FIG> and <FIG>, in the shift lever <NUM>, the long arm <NUM> extends obliquely downward toward a front side from the attachment portion <NUM> serving as a swing fulcrum, and the short arm <NUM> extends substantially downward from the attachment portion <NUM>. The long arm <NUM> extends toward a lower end of the shift sensor <NUM>, and the operation portion <NUM> at a tip end of the long arm <NUM> is positioned at a rear side of the shift sensor <NUM>. The shift rod <NUM> extends from the joint <NUM> at a tip end of the short arm <NUM> to the joint <NUM> at an upper portion of the shift sensor <NUM>. The long arm <NUM> crosses an outer side of the shift rod <NUM> in the vehicle width direction, and the long arm <NUM> and the shift rod <NUM> obliquely intersect with each other.

In a non-operated state of the shift lever <NUM>, inclination of the short arm <NUM> substantially coincides with inclination of the shift sensor <NUM>. The shift rod <NUM> extends in a direction orthogonal to the inclination of the short arm <NUM> and the shift sensor <NUM>, and a distance L1 from a front end of the shift sensor <NUM> to a front end of the operation portion <NUM> in an extending direction of the shift rod <NUM> is equal to or less than half of a length L2 of the shift rod <NUM>. Accordingly, the operation portion <NUM> is brought close to the shift sensor <NUM>, and a front-rear length of the shift device <NUM> is reduced. Since the front-rear length of the shift device <NUM> is reduced, a step position is not biased in the front-rear direction, and a riding position of the driver is not impaired.

In a vehicle side view, the operation portion <NUM> and the shift sensor <NUM> are provided below the shift rod <NUM>, and the operation portion <NUM> and a lower portion of the shift sensor <NUM> are positioned at the same height. As a result, the operating portion <NUM> is not positioned too low, and a bank angle can be easily ensured. Since the shift sensor <NUM> is disposed below the shift rod <NUM>, the shift shaft <NUM> that rotates integrally with the shift sensor <NUM> is separated from the drive shaft <NUM> (see <FIG>) of the transmission device. Therefore, the degree of freedom of a shaft arrangement of the transmission device is improved, the shift device <NUM> is separated from a drive chain, and it is easy to arrange the sprocket cover <NUM> (see <FIG>).

In a vehicle side view, the attachment portion <NUM> of the shift lever <NUM> is provided above the shift rod <NUM>, and the attachment portion <NUM> and an upper portion of the shift sensor <NUM> are positioned at the same height. A rear end of the shift rod <NUM> is positioned below a front end of the shift rod <NUM>, and the joint <NUM> at the rear end of the shift rod <NUM> is positioned at the same height as a lower portion of the shift sensor <NUM> and the operation portion <NUM>. Since the shift lever <NUM> and the shift rod <NUM> are accommodated in a range from the upper portion to the lower portion of the shift sensor <NUM>, a height of the shift device <NUM> is reduced. The long arm <NUM> extends obliquely from the attachment portion <NUM> toward the operation portion <NUM>, and a sufficient length of the shift lever <NUM> is ensured.

In this manner, the shift lever <NUM> and the shift rod <NUM> are disposed in a compact manner so as to intersect with each other, so that a front-rear length and a height of the shift device <NUM> are reduced, and the shift device <NUM> is reduced in size. The operation portion <NUM>, the lower portion of the shift sensor <NUM>, and the joint <NUM> at the rear end of the shift rod <NUM> do not need to be positioned at completely the same height. A slight deviation may be generated to such an extent that these heights are considered to be the same height. Similarly, the attachment portion <NUM> and the upper portion of the shift sensor <NUM> do not need to be positioned at completely the same height. A slight deviation may be generated to such an extent that these heights are considered to be the same height.

As described above, according to the present embodiment, the shift sensor <NUM> has a function of detecting a shift operation, and the shift sensor <NUM> functions as a link arm that couples the shift shaft <NUM> and the shift rod <NUM>. Even in a layout in which a sufficient length of the shift rod <NUM> cannot be ensured, the shift sensor <NUM> can be provided in the shift device <NUM>. Since the shift sensor <NUM> and the operation portion <NUM> are positioned below the shift rod <NUM>, the shift lever <NUM> and the shift rod <NUM> are disposed in a compact manner in the same space, and the shift device <NUM> is reduced in size. In addition, since the shift sensor <NUM> is provided instead of a link arm, the number of components is suppressed from increasing, and the shift sensor <NUM> is easily attached.

Although the operation portion and the shift sensor are positioned below the shift rod in the present embodiment, the operation portion and the shift sensor may be positioned at the same side in a manner of sandwiching the shift rod.

Although the Hall IC is used as a sensor portion in the present embodiment, the sensor portion is not limited to the Hall IC. The sensor portion may be, for example, an anisotropic magneto resistive (AMR) sensor as long as the sensor portion can detect a movement of the shift rod.

Although the shift sensor is provided with a pair of protection portions that protect the sensor portion from external forces from above and below in the present embodiment, the shift sensor may be provided with one protection portion so as to protect the sensor portion from external forces at least one of from above and from below. Further, the shift sensor may not be provided with a protection portion.

Although the shift sensor is inclined rearward such that the front side of the lower end of the shift sensor is positioned above the rear side thereof in the present embodiment, the shift sensor may not be inclined, and the shift sensor may be inclined forward.

Although the attachment portion of the shift lever and the upper portion of the shift sensor are positioned at the same height in the present embodiment, a positional relationship between the attachment portion of the shift lever and the upper portion of the shift sensor is not particularly limited.

Although the distance from the front end of the shift sensor to the front end of the operation portion in the extending direction of the shift rod is equal to or less than half of the length of the shift rod in the present embodiment, the distance from the front end of the shift sensor to the front end of the operation portion is not particularly limited. As long as the length of the shift lever can be ensured, the distance from the front end of the shift sensor to the front end of the operation portion may be larger than half of the length of the shift rod.

The shift device may be applied not only to the straddle-type vehicle shown in the drawings but also to a straddle-type vehicle of other types. The straddle-type vehicle is not limited to general vehicles on which a rider rides in a posture of straddling a seat, and also includes a small-sized scooter-type vehicle on which a rider rides without straddling a seat.

Claim 1:
A shift device (<NUM>) for a straddle-type vehicle (<NUM>) that is configured to cause a transmission device to perform a shift change in accordance with rotation of a shift shaft (<NUM>) of the transmission device, the shift device (<NUM>) comprising:
a shift lever (<NUM>) provided with an operation portion (<NUM>) that is configured to receive a shift operation;
a shift sensor (<NUM>) provided on the shift shaft (<NUM>) so as to be integrally rotatable with the shift shaft (<NUM>); and
a shift rod (<NUM>) that couples the shift lever (<NUM>) and the shift sensor (<NUM>),
wherein the shift sensor (<NUM>) is configured to detect the shift operation on the shift lever (<NUM>) in accordance with a movement of the shift rod (<NUM>),
characterized in that
the operation portion (<NUM>) and the shift sensor (<NUM>) are positioned at the same side in a manner of sandwiching the shift rod (<NUM>) in a vehicle front view,
the shift sensor (<NUM>) functions as a link arm and is configured to couple the shift shaft (<NUM>) and the shift rod (<NUM>),
in a non-operated state the shift rod (<NUM>) extends in front-rear direction, and the operation portion (<NUM>) and the shift sensor (<NUM>) are positioned below the shift rod (<NUM>),
and one end of the shift rod (<NUM>) is coupled to an upper portion of the shift sensor (<NUM>) in the vehicle side view, the other end of the shift rod (<NUM>) is positioned below the one end of the shift rod (<NUM>) and is coupled to the shift lever (<NUM>) via a joint (<NUM>), and a lower portion of the shift sensor (<NUM>) and the joint (<NUM>) at the other end of the shift rod (<NUM>) are positioned at the same height in the vehicle side view.