Electric vehicle

An electric vehicle is provided with a highly simple and convenient structure for detachably retaining a battery, and enabling the vehicle to be lifted by hand. A battery case of the electric vehicle includes an upper extension (80F, 80G) including an upper member (80G) configured to be gripped by a hand for lifting the vehicle, and defining a gripping space (112) for receiving the hand between an upper surface of the battery received in the battery case and the upper member, and a latching structure (102, 106, 120) is provided between an upper part of the battery and an opposing part of the battery case, the latching structure including an operating member (104) positioned inside the gripping space.

TECHNICAL FIELD

The present invention relates to an electric vehicle, and in particular to a small electric vehicle such as a personal mobility vehicle provided with a detachable battery.

BACKGROUND ART

In a personal mobility vehicle such as an electric vehicle with inverted pendulum control, it is known to provide a battery case having an open upper and rear end in a rear part of the vehicle body frame and a lid pivoted to an upper end of the battery case to selectively close the open upper end of the battery case. With a projection projecting from the bottom wall of the battery case engaging a corresponding recess formed in the bottom end of the battery, a latch claw formed in the lid selectively engages a latch recess formed in the upper end of the battery so that the battery can be retained in the battery case by engaging the upper and bottom ends of the battery. See JP2013-237334A, for instance.

In a known battery mounting structure for an electric bicycle, a bracket fixedly attached to the vehicle body is provided with a positioning recess and an engagement recess, and the battery is provided with a support pin that is configured to be seated in the positioning recess. The battery is further provided with an engagement projection which is configured to be engaged by the engagement recess as the battery is rotated around the support pin seated in the positioning recess. See JP2000-142551A.

In the prior art disclosed in JP2013-237334A, the battery case is required to be fitted with a pivoted lid which complicates the battery retaining structure.

In the case of the prior art disclosed in JP2000-142551A, the lower part of the battery can be supported in a highly simple manner, but a latching structure is required for securing an upper part of the battery in a stable manner against vibrations and impacts which the vehicle is expected to experience.

In the field of personal mobility, the vehicle is often provided with a handle or a grip for lifting the vehicle for transportation and other purposes, in addition to a battery case for accommodating a battery therein in a detachable manner.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide an electric vehicle which is provided with a highly simple and convenient structure for detachably retaining a battery, and enabling the vehicle to be lifted by hand.

A second object of the present invention is to provide an electric vehicle which is provided with a structure combining a grip for lifting the vehicle and a battery case for detachably retaining a battery in a highly compact manner.

To achieve such objects, the present invention provides an electric vehicle including a vehicle body frame (12), a wheel (14) supported by the vehicle body frame, an electric motor (60) for driving the wheel, and a power unit (26) for supplying electric power to the electric motor, the power unit comprising a battery case (80) provided in a rear part of the vehicle body frame and having a rearwardly facing opening, and a battery (82) configured to be detachably placed in the battery case, wherein the battery case includes an upper extension (80F,80G) including an upper member (80G) configured to be gripped by a hand for lifting the vehicle, and defining a gripping space (112) for receiving the hand between an upper surface of the battery received in the battery case and the upper member, and a latching structure (102,106,120) is provided between an upper part of the battery and an opposing part of the battery case, the latching structure including an operating member (104) positioned inside the gripping space.

Owing to this arrangement, the structure for lifting the vehicle and the structure for accessing the battery can be combined into a compact unit.

The vehicle may consist of an inverted pendulum vehicle.

In a preferred embodiment of the present invention, the operating member includes an operating arm having a base end pivotally supported by the battery case and a free end extending forward, and is configured to release the latching structure by being depressed downward.

For the operating member to be operated by a user, a hand must be inserted into the gripping space with the palm of the hand facing downward. On the other hand, for lifting the vehicle by inserting a hand into the gripping space, the palm of the hand must be facing upward. Therefore, when lifting the vehicle, an inadvertent operation of the operating member can be prevented.

Preferably, the operating arm extends forward with a downward slant.

In this arrangement, the operating arm is required to be moved in a rearward direction so that the operating arm is most effectively prevented from being operated when a hand is inserted into the gripping space with the palm of the hand facing upward.

The upper extension may include a pair of side walls and an upper wall extending between the side walls, the upper member consisting of the upper wall. However, the upper member may also consist of a bar or any other member that is suitable to be held by a hand for lifting the vehicle.

In a particularly preferred embodiment of the present invention, the vehicle is configured to be placed in a forwardly slanted park position, and the battery case includes a bottom wall extending substantially horizontally when the vehicle is in operation, and a slanted wall extending from a rear edge of the bottom wall with a downward slant, the slanted wall being angled in such a manner that the slanted wall extends substantially horizontally when the vehicle is in the park position.

The slanted wall provides a surface for placing the battery in a stable manner when the vehicle is placed in the forwardly slanted park position. Although the battery is relatively heavy, the presence of the slanted wall allows the battery to be installed and removed with a minimum effort.

In a particularly preferred embodiment of the present invention, the battery is provided with a pair of lateral projections located in lower front parts of side surfaces of the battery, and each of opposing side walls of the battery case is provided with a guide slot for guiding a rotational motion of the battery around a lateral axial line and a vertical motion of the battery from and to a state where the battery is placed on the slanted wall.

According to this embodiment, owing to the cooperation between the lateral projections and the guide slots, the battery can be properly positioned on the slanted wall, and tilted forward into a fully received position in an effortless manner when installing the battery into the battery case with the vehicle positioned in the park position. When removing the battery from the battery case, the battery may be raised from the fully received position into an upright position on the slanted wall, and then lifted upward, again, owing to the cooperation between the lateral projections and the guide slots.

For the convenience of lifting and carrying the battery, the battery may be provided with a grip handle in an upper part thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

A preferred embodiment of the present invention is described in the following with reference to the appended drawings.

The illustrated electric vehicle consists of an inverted pendulum vehicle10. The directions mentioned in the following disclosure will be based on the viewpoint of the rider or the occupant of the inverted pendulum vehicle10.

As shown inFIGS. 1 to 3, the inverted pendulum vehicle10includes a vehicle body frame12, a propulsion unit16including a main wheel14, a tail wheel unit20including a tail wheel18, a drive unit22for driving the propulsion unit16, a control unit24for controlling the drive unit22and the tail wheel unit20, a power unit26for supplying electric power to the control unit24, the drive unit22and the tail wheel unit20, and an outer cover28covering the exterior of the propulsion unit16.

The vehicle body frame12includes a pair of vertically extending side posts30located on either side of the vehicle body frame12, and a cross beam (not shown in the drawings) extending laterally between the two side posts30. The upper ends of the side posts30support a saddle32in such a manner that the height of the saddle32may be adjusted with the aid of an adjustment screw34.

A foot rest38is attached to the lower end of each side post30via a mounting bracket36. The bottom side of each foot rest38is fitted with a retractable stand40which extends downward when deployed to support the inverted pendulum vehicle10in a forwardly tilted position (park position) as shown inFIG. 3.

The propulsion unit16is positioned between the two side posts30, and includes a support shaft50extending laterally between the two mounting brackets36, a pair of drive disks52rotatably supported by the support shaft50in an individually rotatable manner, and a pair of driven pulleys54(for cogged belt) attached to the respective drive disks52in a coaxial manner.

Each drive disk52has a frusto-conical shape with the tapered end thereof facing inward, and a plurality of metallic drive rollers (free rollers not shown in the drawings) are rotatably supported on the tapered outer circumferential surface of the drive disk52at a regular angular interval. The rotational center lines of the drive rollers are in a skewed relationship to the rotational center line of the drive disks, and the drive rollers are arranged along the circumference of the two drive disks52in a symmetric manner with respect to the center plane extending longitudinally and vertically through the vehicle body frame12.

The main wheel14includes a metallic annular member56and a plurality of driven rollers (free rollers)58rotatably supported by the annular member56so as to be rotatable around the tangential line of the annular member56. Each driven roller58contacts the road surface as the main wheel14rotates around the rotational center line thereof, and is provided with an outer layer made of rubber for an improved traction. The main wheel14is interposed between the drive disks52in such a manner that the driven rollers and drive rollers engage with each other.

For the details of the mechanism for driving the main wheel14, reference may be made to JP2014-234035A (U.S. Pat. No. 9,511,656B2).

The drive unit22includes a pair of electric motors60and a par of drive pulleys62for cogged belt actuated by the respective electric motors60, and an endless cogged belt64is passed around each drive pulley62and the associated driven pulley54so that the two drive disks52can be individually driven by the respective electric motors60.

The tail wheel18of the tail wheel unit20is attached to a rear end of a tail wheel arm having a front end (base end) pivotally connected to the support shaft50. The tail wheel18consists of an omni-wheel that includes a disk wheel72and a plurality of free rollers74attached to the periphery of the disk wheel72so as to be rotatable around the respective rotational center lines thereof. The tail wheel18contacts the road surface under the gravitational force, and rotatively actuated by an electric motor76mounted on the tail wheel arm70when a yaw movement of the vehicle10is required. The tail wheel18is covered by an outer cover78as shown inFIG. 1.

The control unit24includes a main wheel PDU (not shown in the drawings), a tail wheel PDU (not shown in the drawings), a DC-DC converter (not shown in the drawings) and gyro sensors (not shown in the drawings), and performs an inverted pendulum control by taking into account the tilt angle of the vehicle body frame12and the movement of the gravitation center of the rider seated on the saddle32, in addition to a travel control for the main wheel14, and a cornering control using the tail wheel18.

The inverted pendulum control maintains the vehicle body frame12in an upright posture so that the vehicle10is enabled to stop and travel while maintaining an upright posture as shown inFIGS. 1 and 2.

The power unit26includes a battery case80attached to a rear part of the vehicle body frame12, and a battery (battery pack)82detachable installed in the battery case80.

The battery82includes a substantially rectangular outer shell84containing battery cells (secondary battery cells) in a sealed condition, and an upper frame94integrally formed in an upper part of the outer shell84. The outer shell84and the upper frame94may be made of molded plastic material. The front end of the outer shell84is integrally provided with a front projection86projecting from an otherwise planar front wall of the outer shell. The projecting end of the front projection86defines a planar flat surface which is slightly tilted in the forward direction, and is provided with a central recess88for receiving a female connector90for electric power.

The upper wall86A and the lower wall86B of the front projection86define arcuate surfaces (part-cylindrical surfaces) centered around a lower front part of the outer shell84as will be discussed hereinafter.

A lateral projection92is integrally formed in a front and lower part of each side wall84B of the outer shell83. The lateral projection92is vertically elongated, and the bottom end of the lateral projection92is formed as a semi-cylindrical bottom surface92A having a center extending in the lateral direction.

The upper frame94include a pair of side walls94A continuously connected to the respective side walls84B of the outer shell83, and a rear wall94B continuously connected to the rear wall84C (seeFIG. 1) of the outer shell83so that an upper recess96having an open upper and front end is defined on top of the outer shell83.

An upper front part of the upper frame94is integrally provided with a handle bar95extending laterally in an upper part of the upper recess96between the two side walls94A. The handle bar95is configured to be held by a hand for transporting the battery82.

As shown inFIG. 4, a support shaft98extends laterally in an upper rear part of the upper recess96between the two side walls94A. A battery side latch member100made of plastic material is pivotally supported by the support shaft98. The battery side latch member100includes a pair of engagement claws102A located on either side of the battery side latch member100and directed upward, and an operating arm104having the shape of a rectangular plate extending between the two claws102A. A torsion coil spring106is wound around the support shaft98and is engaged by the rear wall94B of the upper frame94at one end and by the battery side latch member100at the other end so that the battery side latch member100is biased in an upward direction (clockwise direction inFIG. 4). The battery case80is provided with a case side latch member120which is fixedly attached to the battery case80, and is configured to engage the engagement claws102A of the battery side latch member100when the battery82is received in the battery case80. When the engagement claws102are pivoted in the downward direction (counterclockwise direction inFIG. 4) by manually depressing the operating arm104against the spring force of the torsion coil spring106, the engagement claws102A of the battery side latch member100are released from the case side latch member120so that the battery82can be removed from the battery case80as will be described hereinafter.

As shown inFIG. 4, the operating arm104is slanted such that the free end (front end) of the operating arm104is lower than the base end thereof. Therefore, when operating the operating arm104, the free end of the operating arm104is required to be moved in a downward and rearward direction.

The battery case80is made of molded plastic member, and is provided with a bottom wall80A which extends substantially horizontally when the vehicle10is in the upright posture, a slanted wall80B which extends rearward from the rear edge of the bottom wall80A. The slanted wall80B is configured such that the slanted wall80B extends substantially horizontally when the vehicle10is in the prescribed forwardly tilted position (park position). The battery case80further includes a pair of side walls80C extending upright from the respective side edges of the bottom wall80A and the slanted wall80B, a front wall80D connecting the front edges of the side walls80C and the bottom wall80A to one other, and an upper wall80E connecting the upper edges of the side walls80C and the front wall80D. Thus, the battery case80is formed as a generally rectangular box having an open rear end and internally defines a battery chamber107.

When the battery82is received in the battery chamber107, the side walls80C of the battery case80opposes the respective side walls84B and94A of the outer shell83of the battery82with a small gap, and the front wall84A of the outer shell83of the battery abuts the front wall80D of the battery case80.

The front wall80D of the battery case80is provided with a front recess109which is recessed forward so as to be complementary to the front projection86of the battery82. More specifically, the front recess109is defined by an arcuate upper wall108A and an arcuate lower wall108B corresponding to the upper wall86A and the lower wall86B of the front projection86. A male connector110for conducting electricity from and into the battery82in cooperation with the female connector90of the front projection86is provided in a front wall108C of the front recess109.

The battery case80is further provided with an upper wall extension80G which is connected to the rear edge of the upper wall80E via an upright wall80F. The side edges of the upper wall extension80G and the upright wall80F are continuously connected to the upper edges of the respective side walls80C of the battery case80. Therefore, a space having an open rear end is defined between the upper end of the battery82(the upper frame94of the outer shell83) and the upper wall extension80G. This space is referred to as a gripping space112in the following disclosure.

The gripping space112can be used for lifting the vehicle10. A hand of a user may be inserted into the rear opening of the gripping space112with the palm of the hand facing upward to grip (or hook) the upper wall80E to lift the vehicle10, for instance, for transporting the vehicle10from one place to another.

The case side latch member120is made of a metallic hook member insert molded in the rear end part of the upper wall80E of the battery case80.

A lower front part of each side wall80C of the battery case80is integrally provided with a battery support portion114which defines a guide slot116extending in an upward and rearward direction and having an open rear end. In particular, the lower surface of the guide slot116defines a linear plane with a downward slant toward the front part thereof. The slant angle of the guide slot116is determined such that the guide slot116extends vertically when the vehicle is in the forwardly tilted park position. The rear end of the guide slot116has a dimension that is slightly greater than the width (fore and aft dimension) of the corresponding lateral projection92of the battery outer shell84, but significantly smaller dimension than the length (vertical dimension) of the corresponding lateral projection92of the battery outer shell84. The lower front end of the guide slot116is enlarged, and has a slightly greater vertical dimension than the length (vertical dimension) of the corresponding lateral projection92of the battery outer shell84.

Typically, when installing the battery82into the battery case80, the inverted pendulum control of the vehicle10is terminated, and the vehicle10is put into the forwardly tilted position (park position) with the stands40deployed and engaged by the ground surface.

Therefore, when the battery82is about to be fitted into the battery chamber107with each lateral projection92engaged by the corresponding guide slot116, the battery82is guided vertically downward onto the slanted wall80B. In the forwardly tilted position (park position) of the vehicle10, the slanted wall80B is placed in a horizontal position, and the battery may be placed on the slanted wall80B in a stable manner. Once each lateral projection92reaches the bottom (front) end of the corresponding guide slot116, the battery82is allowed to be tilted in the forward direction or into an upright posture (with respect to the vehicle body frame12) so that the battery82is fully received in the battery chamber107.

More specifically, the bottom surface92A of each lateral projection92abuts the bottom surface116B of the corresponding guide slot116. By pushing an upper part of the battery82, the battery82may be tilted forward around the point of contact between the bottom surfaces92A of the lateral projections92and the bottom surfaces116B of the corresponding guide slots116. Thereby, the battery82is fully received in the battery chamber107. At the same time, the male connector110on the side of the battery case80is fully fitted into the female connector90on the side of the battery82.

Also, the engagement claw102A is engaged by the case side latch member120. At this time, the lateral projections92are received in the lower ends of the guide slots116so that the battery82is positively retained in the battery chamber107at both the upper end and the lower end thereof.

When removing the battery82from the battery case80, the inverted pendulum control of the vehicle10is terminated, and the vehicle10is put into the forwardly tilted position (park position) with the stands40deployed and engaged by the ground surface.

The user (rider) then inserts a hand into the rear opening of the gripping space112with the palm of the hand facing downward. By pressing the operating arm104downward and/or rearward, the engagement claw102A is disengaged from the case side latch member120. By pulling the upper part of the battery82rearward, the battery82is caused to tilt rearward around the point of contact between the bottom surfaces92A of the lateral projections92and the bottom surfaces116B of the corresponding guide slots116. Thus, the battery82is placed upright on the slanted wall80B in spite of the forwardly tilted state of the vehicle10.

At this time, the guide slot116extends vertically so that the battery82may be pulled upward. Therefore, the user is enabled to grip the handle bar95, and pull up the battery82with a minimum effort.

According to the illustrated embodiment, the battery82can be temporarily placed on the slanted wall when installing the battery82and removing the battery82. Therefore, even though the battery82is relatively heavy, the user can install and remove the battery with a minimum effort. Also, the operating arm104is normally concealed inside the gripping space112so that an inadvertent operation of the operating arm104can be avoided.

When lifting the vehicle10by a hand, the hand is inserted in the gripping space112from the rear direction with the palm of the hand facing upward. Therefore, an inadvertent operation of the operating arm104can be avoided.

Thus, according to the illustrated embodiment, the arrangement for enabling the vehicle10to be lifted, and the arrangement for accessing the battery82are combined in a limited space so that the external appearance of the vehicle is enhanced, and the number of necessary components can be minimized. Also, even though the gripping space112serves the dual purposes of lifting the vehicle10and accessing the battery82, an inadvertent releasing of the engagement claw102A can be avoided.

Although the present invention has been described in terms of preferred embodiments thereof, it is obvious to a person skilled in the art that various alterations and modifications are possible without departing from the spirit of the present invention. For instance, the present invention may also be applied to electric bicycles and other small vehicles.