JP2013086703A - Electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric vehicle capable of preventing a vehicle body from being laterally turned by maintaining the vehicle body horizontal with a simple configuration.SOLUTION: This electric wheelchair 1 as the electric motor chaired vehicle is configured, for an example, to drive a rear wheel 13a upward and a rear wheel 13b downward at the same time by drive of a motor 16. In the case wherein the vehicle body 11 tilts in the lateral direction due to an inclined surface, a step or the like, the rear wheel 13a on an upper side of the tilt is driven upward, and at the same time, the rear wheel 13b on a lower side of the tilt is driven downward. A deviation between driving timings when maintaining the vehicle body 11 horizontal can be thereby prevented, and the electric wheelchair 1 can be surely prevented from being laterally tuned.

Description

  The present invention relates to an electric vehicle that can be driven by a motor.

  The electric wheelchair, which is one of the general electric vehicles, supports the left and right wheels by suspensions, so that the vehicle body is inclined, for example, in the direction of the left wheel due to an inclined surface or a step, and the load on the left wheel side is increased. When it becomes larger, the suspension on the left wheel side further sinks and it becomes easier to roll over. Although the tilt absorption performance can be increased by softening the suspension, problems such as a decrease in ride comfort and subsidence (pitching) at the time of stopping occur.

  Therefore, for example, in Japanese Patent Application Laid-Open No. 11-197191 (Patent Document 1) and Japanese Patent No. 4687309 (Patent Document 2), a pair of frames mounted on the left and right sides of the body frame so as to be swingable in the vertical direction. An electric wheelchair is described that includes a swing arm, wheels that are rotatably attached to each swing arm, and a telescopic cylinder that swings each swing arm in the vertical direction. According to this electric wheelchair, when the vehicle body is inclined in the lateral direction due to an inclined surface or a step, the vehicle body can be held horizontally by contracting the telescopic cylinder on the upper side of the tilt and extending the telescopic cylinder on the lower side of the tilt. it can.

  Japanese Patent Laid-Open No. 2008-48760 (Patent Document 3) discloses a curved beam that forms a part of an arc attached to the lower part of a seat, and an upper part of a vehicle body that is slidably contacted with the curved beam in a circumferential direction. An electric wheelchair with possible rollers is described. According to this electric wheelchair, when the vehicle body is inclined in the lateral direction due to an inclined surface, a step, or the like, the bending beam is slid in the inclined direction by the roller, so that the seat can be held horizontally.

JP 11-197191 A Japanese Patent No. 4687309 JP 2008-48760 A

  In the electric wheelchairs described in Patent Documents 1 and 2, it is necessary to extend and retract the telescopic cylinders attached to the swing arms and move the wheels up and down to hold the vehicle body horizontally. For this reason, when the expansion / contraction timing of each expansion / contraction cylinder shifts, there exists a possibility that a vehicle body may incline and an electric wheelchair may roll over. In addition, since an air cylinder is used as the telescopic cylinder, the response is poor and it is difficult to cope with a sudden movement such as wheel removal. Moreover, in the electric wheelchair described in Patent Document 3, the seat can be held horizontally by the gravity of a seat or the like hanging on the bending beam. However, since the vehicle body remains inclined in the lateral direction, the electric wheelchair may roll over depending on the inclination angle.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electric vehicle capable of preventing a rollover by holding the vehicle body horizontally with a simple configuration.

  (Embodiment 1) An electric vehicle according to the present invention includes a vehicle body, at least a pair of wheels for running the vehicle body, and supported by the vehicle body, wherein the pair of wheels are rotatably supported, and one of the wheels An electric vehicle comprising a drive mechanism capable of simultaneously driving the other wheel in the upward direction and the other wheel in the downward direction, and one motor for simultaneously driving the pair of wheels by driving the drive mechanism.

  (Claim 2) The drive mechanism may be configured such that the pair of wheels can be moved in the upside down direction and in the same amount of movement, with a movement amount corresponding to the rotational drive angle of the motor. .

  (Claim 3) The electric vehicle may include a guide member fixed to the vehicle body and at least one suspension for supporting the drive mechanism with respect to the guide member.

  (Claim 4) The drive mechanism includes a pair of rack gears that rotatably support the pair of wheels, and a pinion gear that can simultaneously mesh with the pair of rack gears, and the motor includes the pinion gear. The pair of rack gears may be moved in opposite directions by rotating.

  (Claim 5) The drive mechanism includes a pair of feed screws that rotatably support the pair of wheels, a pair of nuts that can be screwed to the pair of feed screws, and the pair of nuts that rotate simultaneously. A spur gear mechanism, and the motor may rotate the spur gear mechanism to rotate the pair of nuts and move the pair of feed screws in directions opposite to each other.

  (Claim 6) The drive mechanism includes a pair of swing arms for rotatably supporting the pair of wheels, and a bevel gear mechanism capable of simultaneously turning the pair of swing arms together with the pair of wheels in a reverse direction; The motor may rotate the bevel gear mechanism to turn the pair of swing arms together with the pair of wheels in opposite directions.

  (Claim 1) The electric vehicle is configured to simultaneously drive one wheel upward and the other wheel downward by driving one motor. As a result, when the vehicle body is inclined in the lateral direction due to an inclined surface or a step, the upper wheel is driven upward, and the lower wheel is simultaneously driven downward, so that the vehicle body is held horizontally. There is no deviation in the driving timing at that time, and the rollover of the electric vehicle can be reliably prevented.

  (Claim 2) The drive mechanism has a configuration in which the pair of wheels are moved in the upside down direction and in the same amount of movement, with a movement amount corresponding to the rotational drive angle of the motor. Thereby, since the movement accuracy of a pair of wheels can be raised, a vehicle body can be held horizontally reliably.

  (Claim 3) One suspension is configured to support the drive mechanism with respect to the guide member fixed to the vehicle body. As a result, the tilt absorbing function by the drive mechanism and the shock absorbing function by the suspension can be configured separately, so that the shock absorbing performance remains the same regardless of the width of the tilt absorbing performance, and the ride comfort is reduced or stopped. Time subsidence (pitching) can be prevented.

  (Claim 4) The drive mechanism is configured to move the pair of rack gears in opposite directions by the rotation of one pinion gear driven by one motor, and to drive the pair of wheels in the upward and downward directions, respectively. . Thus, since the drive mechanism can be configured with a simple mechanism, the vehicle body can be held horizontally and the cost of the electric vehicle can be reduced.

  (Claim 5) The drive mechanism rotates a pair of nuts simultaneously by rotation of a spur gear mechanism driven by one motor, moves a pair of feed screws in opposite directions, and moves a pair of wheels upward and downward. Each is driven. Thus, since the drive mechanism can be configured with a simple mechanism, the vehicle body can be held horizontally and the cost of the electric vehicle can be reduced.

  (Claim 6) The drive mechanism is configured to simultaneously turn the pair of swing arms together with the pair of wheels in the same direction by the rotation of the bevel gear mechanism driven by one motor. Thus, since the drive mechanism can be configured with a simple mechanism, the vehicle body can be held horizontally and the cost of the electric vehicle can be reduced.

It is the whole view which looked at the electric wheelchair from the side. (A) is a top view of the rear drive mechanism of 1st Embodiment of an electric wheelchair, (B) is AA sectional view, (C) is BB sectional drawing. It is a flowchart for demonstrating operation | movement of an electric wheelchair. (A) is a figure which shows the state of the rear drive mechanism in a flat surface, (B) is a figure which shows the state of the rear drive mechanism in an inclined surface. (A) is a top view of the rear drive mechanism of 2nd Embodiment of an electric wheelchair, (B) is an AA sectional view, (C) is a BB sectional drawing. It is a schematic block diagram which shows the drive mechanism of the rear drive mechanism of 3rd Embodiment of an electric wheelchair. It is a schematic block diagram which shows the drive mechanism of the rear drive mechanism of 4th Embodiment of an electric wheelchair. (A) is a schematic block diagram which shows the drive mechanism of the rear drive mechanism of 5th Embodiment of an electric wheelchair, (B) is the figure which looked at it from the side.

(1. Mechanical configuration of electric wheelchair)
The electric wheelchair, which is one of the electric vehicles, is a four-wheel electric wheelchair that is driven and operated by a passenger, and includes an overall view of the electric wheelchair 1 in FIG. 1 and a rear drive mechanism 15 of the electric wheelchair 1 in FIG. This will be described with reference to these three views.

  As shown in FIG. 1, the electric wheelchair 1 includes a vehicle body 11, a pair of front wheels 12a, 12b and a pair of rear wheels 13a, 13b, and a pair of rear wheels 13a, 13b for running the vehicle body 11, respectively. The rear drive mechanism 15 that can be driven in the vertical direction and a single motor 16 that drives the rear drive mechanism 15 are schematically configured.

  The vehicle body 11 has a general structure in which a handle 3 and a seat 4 are attached to the frame 2. The handle 3 and the seat 4 are attached to the upper part of the frame 2 that can be operated by a passenger sitting on the seat 4 holding the handle 3. A battery 5 for driving the motor 16 and the like is attached to the frame 2 below the seat 4. Further, a control device C including a gyro sensor 6 that detects the inclination of the vehicle body 11 and a G sensor 7 that detects a lateral G (acceleration) applied to the vehicle body 11 is provided inside the seat 4.

  In-wheel motors 21a, 21b and 31a, 31b are built in the front wheels 12a, 12b and the rear wheels 13a, 13b. The axles 32 a and 32 b of the rear wheels 13 a and 13 b are fixed to the rear drive mechanism 15. The front wheels 12a, 12b and the rear wheels 13a, 13b are configured to be rotatable around the axles 22a, 22b and 32a, 32b by in-wheel motors 21a, 21b and 31a, 31b, respectively.

  As shown in FIG. 2, the electric wheelchair 1 includes one suspension 8 that supports the rear drive mechanism 15 with respect to the rear guide member 51 fixed to the frame 2 of the vehicle body 11. The suspension 8 is constituted by a spring and a damper.

  The rear drive mechanism 15 includes a pair of rack gears 53a and 53b, a pinion gear 54 that can mesh with the pair of rack gears 53a and 53b at the same time, and a bracket 56 that supports the pinion gear 54, the motor 16, and the suspension 8. .

  The pair of rack gears 53a and 53b has a T-shaped cross section perpendicular to the longitudinal direction, and teeth are formed on the tops of the T-shaped legs. The pair of rack gears 53a and 53b are arranged so that teeth are opposed to each other at a predetermined interval in the rear guide member 51 in parallel. The pinion gear 54 is arranged so that the teeth of the pinion gear 54 can mesh with the teeth of a pair of opposing rack gears 53a and 53b at the same time. That is, the interval between the pair of rack gears 53 a and 53 b is set to be substantially the same as the pitch circle diameter of the pinion gear 54.

  The pair of rack gears 53 a and 53 b are configured to move in directions opposite to each other (upward and downward) by the rotation of the pinion gear 54 driven by the motor 16. The axles 32a and 32b of the rear wheels 13a and 13b are fixed to the head portions of the T-shape at the lower portions of the pair of rack gears 53a and 53b so as to protrude outward.

  The bracket 56 includes a first holding member 56a having a longitudinal cross-sectional shape formed in a substantially C shape, and a rod-like second holding member 56b integrated with the first holding member 56a in the longitudinal direction. ing. The motor 16 is fixed to the first holding member 56a of the bracket 56, and a pinion gear 54 fitted on the shaft of the motor 16 is rotatably supported. The suspension 8 is inserted into the second holding member 56b. ing. And the 2nd holding member 56b of the bracket 56 is inserted in the hole 58a drilled in the connection frame 58 mentioned later.

  The rear guide member 51 includes a pair of rear rack frames 57a and 57b having a C-shaped planar shape and a connecting frame 58 having an H-shaped planar shape for connecting and holding the pair of rear rack frames 57a and 57b in parallel and at a predetermined interval. And a pair of I-shaped connecting frames 59.

  In the rear rack frames 57a and 57b, guide grooves 571a and 571b through which the T-shaped head portions of the pair of rack gears 53a and 53b are inserted to guide sliding in the longitudinal direction are formed so as to penetrate therethrough. The pair of rear rack frames 57a and 57b are arranged at intervals that can hold the pair of rack gears 53a and 53b meshing with the pinion gear 54. And in order to hold | maintain the said space | interval, the connection frame 58 is fixed to the upper end part of a pair of rack gear 53a, 53b, and a pair of connection frame 59 is fixed below the pair of rack gear 53a, 53b.

(2. Operation of electric wheelchair)
The operation of the electric wheelchair 1 will be described with reference to the flowchart of FIG. 3 and the state diagram of the rear drive mechanism 15 of FIG. The state of the front drive mechanism 14 is the same as the state of the rear drive mechanism 15 as described above. The passenger puts his / her hand on the handle 3 of the electric wheelchair 1 stopped on the horizontal plane and sits on the seat 4 and turns on the activation switch provided on the handle 3. Then, the control device C confirms whether or not sensor data is transmitted from the gyro sensor 6 or the G sensor 7 (step 1). At this time, as shown in FIG. 4A, since the electric wheelchair 1 is stopped on the horizontal plane FS and no sensor data is transmitted, the pair of rack gears 53a, 53b (rear wheels 13a, 13b) of the rear drive mechanism 15 are used. ) Are held at the same height by the pinion gear 54.

  The occupant starts traveling by grasping an accelerator lever provided on the handle 3. Then, when the sensor data is transmitted, the control device C determines whether or not the sensor data is transmitted from the gyro sensor 6 (step 2). When the sensor data is transmitted from the gyro sensor 6, it is determined that the electric wheelchair 1 has entered an inclined surface or a step. Since the sensor data is an angular velocity, the angular velocity is integrated to obtain the tilt angle of the electric wheelchair 1 (step 3). Further, based on the inclination angle, the moving distance of the rack gear 53a (53b) in which the electric wheelchair 1 maintains a horizontal posture is obtained (step 4). Then, based on the moving distance of the rack gear 53a (53b), the rotation angle of the pinion gear 54 is obtained, and the motor 16 is instructed to rotate the pinion gear 54 by the rotation angle (step 5).

For example, as shown in FIG. 4 (B), it is assumed that the electric wheelchair 1 has entered an inclined surface SS having an inclination angle α that is downwardly lowered when viewed from the front, for example. Here, due to the clockwise rotation of the pinion gear 54, the rack gear 53a moves downward and simultaneously the rack gear 53b moves upward. Therefore, the height difference between the rack gear 53a and the rack gear 53b becomes twice the moving distance. Therefore, if the distance between the rear wheels 13a and 13b is L, the movement distance M of the rack gear 53a (53b) is expressed by the following equation (1).
M = (L · tan α) / 2 (1)

When the pitch circle diameter of the pinion gear 54 is D, the rotation angle θ of the pinion gear 54 is expressed by the following equation (2).
θ = (M · 2π) / πD = 2M / D (2)

  On the other hand, in Step 2, when the sensor data is transmission from the G sensor 7, the control device C determines that the electric wheelchair 1 is turning. Since the sensor data is acceleration, an inner angle at which the electric wheelchair 1 does not roll over while turning is determined based on the acceleration (step 6). Further, the moving distance of the rack gear 53a (53b) that maintains the inward tilt angle is obtained (step 7). Then, based on the moving distance of the rack gear 53a (53b), the rotation angle of the pinion gear 54 is obtained, and the motor 16 is instructed to rotate the pinion gear 54 by the rotation angle (step 5).

(3. Effects of the electric wheelchair)
The electric wheelchair 1 is configured to drive one rear wheel 13a upward and the rear wheel 13b downward simultaneously by driving one motor 16, for example. Thereby, when the vehicle body 11 is inclined in the lateral direction due to an inclined surface or a step, for example, the rear wheel 13b on the upper side of the inclination is driven upward, and at the same time, the rear wheel 13a on the lower side of the inclination is driven downward. The front wheels 12a and 12b operate following the rear wheels 13a and 13b. Therefore, there is no deviation in the driving timing when the vehicle body 11 is held horizontally, and the rollover of the electric wheelchair 1 can be reliably prevented.

  In addition, one suspension 8 is configured to support the rear drive mechanism 15 with respect to the rear guide member 51 fixed to the vehicle body 11. Thereby, the inclination absorption function by the rear drive mechanism 15 and the shock absorption function by the suspension 9 can be configured separately. The same applies to the front drive mechanism 14. Therefore, regardless of the width of the tilt absorbing performance, the shock absorbing performance can be maintained the same, and the ride comfort can be prevented from being lowered, and the sinking (pitching) at the time of stopping can be prevented.

(4. Mechanical configuration of another example of rear drive mechanism)
FIG. 5 is a diagram showing a second embodiment of the rear drive mechanism corresponding to FIG. 2, and the same components are denoted by the same reference numerals and detailed description thereof is omitted. The rear drive mechanism 19 of the second embodiment connects a pair of rear rack frames 57a and 57b at the center instead of the bracket 56 provided in the rear drive mechanism 15 of the first embodiment, and includes a pinion gear 54 and a motor. 16 is provided with a pair of I-shaped support frames 91 that support 16. The suspension 8 has one end fixed to the upper surface of the connection frame 58 and the other end fixed to the vehicle body 11. Also in the rear drive mechanism 19 having such a configuration, the same effect as that of the rear drive mechanism 15 of the first embodiment can be obtained.

  FIG. 6 is a schematic configuration diagram showing a rear drive mechanism of the third embodiment of the rear drive mechanism. The rear drive mechanism 62 according to the third embodiment includes a pair of ball screw shafts 63a and 63b and a pair of rack gears 53a and 53b and one pinion gear 54 provided in the rear drive mechanism 15 of the first embodiment. A pair of nuts 64a and 64b that can be screwed to the ball screw shafts 63a and 63b, respectively, and three spur gears 65a, 65b, and 66 that can be engaged with each other. A trapezoidal screw may be used instead of the ball screw. If the relationship between the gear axes is a parallel axis, a helical gear or a toothed gear may be used instead of the spur gear.

  The pair of ball screw shafts 63a and 63b and the pair of nuts 64a and 64b are formed to be reverse screws. The pair of ball screw shafts 63 a and 63 b are arranged in parallel and at a predetermined interval, and are arranged so as to be restricted in rotation in the rear guide member 51. The axles 32a and 32b of the rear wheels 13a and 13b are fixed to the lower portions of the pair of ball screw shafts 63a and 63b. The pair of nuts 64a and 64b are arranged to be rotatable only in the rear guide member 51. And the shaft hole of the spur gears 65a and 65b is each fitted by the outer periphery of a pair of nut 64a, 64b. A spur gear 66 is fitted on the motor shaft of the motor 16. The spur gear 66 is meshed with the spur gears 65a and 65b. In the rear drive mechanism 62 having such a configuration, the same effect as that of the rear drive mechanism 15 of the first embodiment can be obtained.

  FIG. 7 is a schematic configuration diagram showing the rear drive mechanism of the fourth embodiment of the rear drive mechanism corresponding to FIG. 6, and the same components are denoted by the same reference numerals and detailed description thereof is omitted. The rear drive mechanism 72 of the fourth embodiment meshes the spur gear 66 fitted to the motor 16 of the rear drive mechanism 62 of the third embodiment only with the spur gear 65b, and meshes the spur gear 65b with the spur gear 65a. It is the composition made to do. In the rear drive mechanism 72 having such a configuration, the same effect as that of the rear drive mechanism 15 of the first embodiment can be obtained. In the rear drive mechanism 62 of the third embodiment and the rear drive mechanism 72 of the fourth embodiment, the pair of nuts 64a and 64b are restricted in rotation and fixed to the axles 32a and 32b of the rear wheels 13a and 13b. The pair of ball screw shafts 63a and 63b may be configured to be rotatably arranged and fitted to the spur gears 65a and 65b.

  FIG. 8 is a schematic configuration diagram showing the rear drive mechanism of the fifth embodiment of the rear drive mechanism corresponding to FIG. 6A, and the same components are denoted by the same reference numerals and detailed description thereof is omitted. . The rear drive mechanism 82 of the fifth embodiment includes a pair of ball screws 63a, 63b, a pair of nuts 64a, 64b, and three spur gears 65a, 65b, 66 provided in the rear drive mechanism 62 of the third embodiment. Instead of this, a pair of swing arms 83a, 83b and three bevel gears 84a, 84b, 85 that can mesh with each other are provided.

  The pair of swing arms 83 a and 83 b are arranged so as to face each other in parallel and at a predetermined interval, and their upper ends are arranged so as to be turnable on the rear guide member 51. And bevel gears 84a and 84b are fitted to the pivot shafts 86a and 86b of the pair of swing arms 83a and 83b, respectively. The axles 32a and 32b of the rear wheels 13a and 13b are fixed to the lower portions of the pair of swing arms 83a and 83b. A bevel gear 85 is fitted on the motor shaft of the motor 16. The bevel gear 85 is meshed with the bevel gears 84a and 84b. In the rear drive mechanism 82 having such a configuration, the rear wheels 13a and 13b move up and down by turning the pair of swing arms 83a and 83b. However, the rear drive mechanism 82 is the same as the rear drive mechanism 15 in the first embodiment. An effect can be obtained.

(5. Modifications)
In the above-described embodiment, the rear wheels 13a and 13b are configured to move up and down. However, even in the configuration in which the front wheels 12a and 12b are moved up and down, the front and rear wheels 12a, 12b, 13a, and 13b are connected to the drive mechanism 15. May be provided. Moreover, it is applicable to electric wheelchairs such as two wheels or three wheels. In addition to the electric wheelchair, it can be applied to a general electric vehicle. Moreover, although it was set as the structure provided with the gyro sensor 6 and the G sensor 7, it is good also as a structure provided only with either one. Further, the front wheels 12a, 12b and the rear wheels 13a, 13b have in-wheel motors 21a, 21b and 31a, 31b built in, but the left and right wheels are driven from one motor through a differential gear and a constant velocity joint. Alternatively, the rotation may be distributed.

1: Electric wheelchair, 6: Gyro sensor, 7: G sensor, 8: Suspension 11: Car body, 12a, 12b: Front wheel, 13a, 13b: Rear wheel 15, 19, 62, 72, 82: Rear drive mechanism, 16 : Motor, 51: Rear guide member 53a, 53b: Rack gear, 54: Pinion gear 56: Bracket 63a, 63b: Ball screw shaft, 64a, 64b: Nut 65a, 65b, 66: Spur gear 83a, 83b: Swing arm, 84a, 84b , 85: Bevel gear, C: Control device

Claims (6)

The car body,
At least a pair of wheels for running the vehicle body;
A drive mechanism supported by the vehicle body, the pair of wheels being rotatably supported, and capable of simultaneously driving one wheel in the upward direction and the other wheel in the downward direction;
An electric vehicle comprising: one motor that drives the pair of wheels simultaneously by driving the drive mechanism. In claim 1,
The drive mechanism is an electric vehicle configured such that the pair of wheels can be moved in the upside down direction and the same amount of movement with a movement amount corresponding to a rotation driving angle of the motor. In claim 1 or 2,
The electric vehicle includes a guide member fixed to the vehicle body and at least one suspension that supports the drive mechanism with respect to the guide member. In any one of Claims 1-3,
The drive mechanism includes a pair of rack gears that rotatably support the pair of wheels, and a pinion gear that can mesh with the pair of rack gears at the same time, and the motor rotates the pinion gears to rotate the pair of gears. Electric vehicle that moves the rack gears in opposite directions. In any one of Claims 1-3,
The drive mechanism includes a pair of feed screws that rotatably support the pair of wheels, a pair of nuts that can be screwed to the pair of feed screws, and a spur gear mechanism that can rotate the pair of nuts simultaneously. And the motor rotates the spur gear mechanism to rotate the pair of nuts and moves the pair of feed screws in directions opposite to each other. In any one of Claims 1-3,
The drive mechanism includes a pair of swing arms that rotatably support the pair of wheels, and a bevel gear mechanism that can simultaneously turn the pair of swing arms together with the pair of wheels in the reverse direction. Is an electric vehicle that rotates the bevel gear mechanism to turn the pair of swing arms together with the pair of wheels in opposite directions.

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