Electric wheelchairs and power units for electric wheelchairs

Abstract

To provide an electric wheelchair that reduces the width of the vehicle when the frame is folded, without reducing the battery capacity. [Solution] The electric wheelchair 100 includes an electric motor 21 mounted on the right wheel 10R, an electric motor 21 mounted on the left wheel 10L, a battery 30 for supplying current to the electric motors 21, and a battery holder 40 that houses the battery 30 and is positioned closer to the right wheel 10R than the center of the electric wheelchair 100 in the left-right direction. The battery holder 40 is open inwards, towards the center of the electric wheelchair 100 in the left-right direction, and upwards of the electric wheelchair 100.

Description

Technical Field

[0006] , , , , , ,

[0005] , , , , ,

[0001] The present disclosure relates to an electric wheelchair and a power unit of the electric wheelchair.

Background Art

[0002] Patent Document 1 below discloses an electric wheelchair. The electric wheelchair has an electric motor disposed on left and right wheels and a battery for supplying power to the electric motor. Further, the electric wheelchair disclosed in Patent Document 1 is foldable so that the distance between the left and right wheels becomes small. In this electric wheelchair, a battery pack for accommodating the battery is disposed on the back surface of the backrest.

[0003] Unlike the electric wheelchair of Patent Document 1, an electric wheelchair having a battery holder disposed along the wheel is also used. In this type of electric wheelchair, the battery holder is in a box shape opened upward and has four wall portions surrounding the left side surface, the front surface, the right side surface, and the rear surface of the battery.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An electric wheelchair may be loaded onto a vehicle in a folded state or stored at home in a folded state. Therefore, it is desirable that the width in the left-right direction of the electric wheelchair in the folded state is small.

Means for Solving the Problems

[0006] (1) The power unit proposed in this disclosure is mounted on an electric wheelchair that is foldable such that the distance between the first wheel and the second wheel is small, and has a first wheel which is one of the right wheel and the left wheel, and a second wheel which is the other of the right wheel and the left wheel. The power unit has a first electric motor mounted on the first wheel, a second electric motor mounted on the second wheel, a battery for supplying current to the first electric motor and the second electric motor, and a battery holder which is located closer to the first wheel than the center of the electric wheelchair in the left-right direction and houses the battery. The battery holder is open inward, which is toward the center of the electric wheelchair in the left-right direction, and toward the top of the electric wheelchair.

[0007] (2) In the power unit of (1), the battery has a first side surface that faces inward. When the battery is mounted in the battery holder, the entire first side surface is exposed inward from the battery holder.

[0008] (3) In the power unit of (1) or (2), the battery has a front surface facing forward of the electric wheelchair and a rear surface facing backward of the electric wheelchair. The battery holder has a front wall portion along the front surface and a rear wall portion along the rear surface. The front wall portion has a first inner surface along the front surface of the battery. The rear wall portion has a second inner surface along the rear surface of the battery. The width of the first inner surface and the second inner surface in the left-right direction is smaller than the width of the battery in the left-right direction.

[0009] (4)(3) In the power unit, when the battery and the battery holder are viewed in the front-rear direction, the center of gravity of the battery coincides with the front wall and the rear wall.

[0010] (5) In the power unit of (3) or (4), when the battery and the battery holder are viewed in the front-rear direction, the plane passing through the center of the battery in the left-right direction intersects the front wall and the rear wall.

[0011] In the power unit described in any of (6)(3) to (5), the positions of the upper surfaces of the front wall and the rear wall are higher than the center of the battery in the vertical direction.

[0012] (7) In the power unit described in any of (1) to (6), the battery has a first side facing inward and a second side facing outward, opposite to the inward direction. The battery holder includes a side wall portion along the second side of the battery. The side wall portion has an inner surface facing inward. The inner surface has a slope at its uppermost part. The slope extends diagonally upward and outward from the lower edge of the slope.

[0013] (8) In the power unit described in any of (1) to (7), the battery holder has a guide portion. The battery has a guided portion. The guide portion and the guided portion allow vertical movement of the battery relative to the battery holder and restrict inward movement of the battery relative to the battery holder.

[0014] (9) The electric wheelchair proposed in this disclosure comprises the power unit described in any of (1) to (7), the first wheel, and the second wheel.

[0015] The electric wheelchair described in (10)(9) has a stopper portion located closer to the second wheel than the center of the electric wheelchair in the left-right direction. The battery holder has a stoppered portion. The stopper portion and the stoppered portion are in contact with each other when the electric wheelchair is folded, and restrict the distance between the first wheel and the second wheel from becoming smaller than a preset value.

[0016] In the electric wheelchair described in (11)(10), the battery holder has the side facing inward. The stopper portion is provided on the side.

[0017] In the electric wheelchair described in (12), (10), or (11), the battery holder has a bottom that supports the lower surface of the battery. The stopper portion is provided on the bottom.

[0018] (13) In the electric wheelchair described in any of (10) to (12), the battery has a front surface facing forward of the electric wheelchair and a rear surface facing backward of the electric wheelchair. The battery holder has a front wall portion along the front surface and a rear wall portion along the rear surface. When the battery is mounted in the battery holder, the battery has a portion that is located inward from the inward side surfaces of the front wall portion and the rear wall portion. A space is secured inward of the battery holder for the portion of the battery to be positioned. When the electric wheelchair is folded with the battery removed from the battery holder, the frame closer to the second wheel is located in front of the space.

[0019] In the electric wheelchair described in any of (14)(10) to (13), the battery has a first side facing inward and a second side facing outward, opposite to the inward direction. The battery holder includes a side wall portion along the second side of the battery. The side wall portion has an inner surface facing the center in the left-right direction of the electric wheelchair. The inner surface has a slope at its uppermost part, and the slope extends diagonally upward and outward from the lower edge of the slope. The battery holder is supported away from the first wheel in the inward direction. [Effects of the Invention]

[0020] According to the power unit and electric wheelchair proposed in the present disclosure, without reducing the capacity of the battery, the width of the vehicle body in the left-right direction in the folded state of the frame can be reduced.

Brief Description of the Drawings

[0021] [Figure 1] It is a perspective view of the electric wheelchair facing obliquely from the left rear. [Figure 2] It is a perspective view of the electric wheelchair facing obliquely from the right rear. [Figure 3] It is a rear view of the battery holder, battery, and right wheel. [Figure 4] It is a perspective view of the battery holder. [Figure 5] It is a plan view of the battery holder. [Figure 6A] It is a left side view of the battery. [Figure 6B] It is a perspective view of the battery. [Figure 7] It is a rear view showing the folded state of the frame.

Modes for Carrying Out the Invention

[0022] Hereinafter, the electric wheelchair and the power unit of the electric wheelchair proposed in the present disclosure will be described. Hereinafter, as an example of the electric wheelchair and the power unit proposed in the present disclosure, the electric wheelchair 100 and the power unit U shown in FIG. 1 and the like will be described. The power unit U includes, as components, the left and right electric motors 21, the battery 30, and the battery holder 40, which will be described later.

[0023] In the following description, the Z1 and Z2 directions shown in FIG. 1 are referred to as the upper and lower directions, respectively. Also, the Y1 and Y2 directions shown in FIG. 1 are referred to as the front and rear directions, respectively, and similarly, the X1 and X2 directions shown in FIG. 1 are referred to as the right and left directions, respectively.

[0024] As shown in Figure 1, the electric wheelchair 100 has wheels 10R and 10L positioned on the right and left sides of the vehicle body, respectively. Wheels 10R and 10L each have a hub 11 and an electric motor 21 located inside the hub 11. The electric motor 21 has a motor housing 23 (see Figure 2), a rotor housed in the motor housing 23, and a stator. The rotation of the rotor is transmitted to the hub 11 via a reduction mechanism located inside the hub 11.

[0025] As shown in Figure 1, the electric wheelchair 100 has a battery 30 that stores power supplied to the electric motor 21, and a battery holder 40 that holds the battery 30. The battery 30 is electrically connected to the electric motors 21 mounted on the left and right wheels 10L and 10R via cables. As shown in Figure 6A, the battery 30 has a battery body 31 that houses multiple battery cells, and a handle 32 provided on the top of the battery body 31.

[0026] As shown in Figure 1, the electric wheelchair 100 has casters 66 positioned in front of the wheels 10R and 10L, foot supports 61 for the user's feet, a seat 62 for the user to sit on, a back support 63 for supporting the user's back, and arm supports 64 for the user's arms. An operating unit (not shown) that receives input from the user is positioned in front of the arm supports 64. Through this operating unit, the user can input instructions regarding the direction and speed of the wheelchair 100 to the control device.

[0027] As shown in Figure 1, the electric wheelchair 100 has a frame 50. The frame 50 has a right frame section 51R which forms the right side of the vehicle body and a left frame section 51L which forms the left side of the vehicle body. The right frame section 51R and the left frame section 51L each have a rear frame section 52, a seat frame section 53, a lower frame section 54, etc. The rear frame section 52 extends vertically and supports the right and left sides of the back support 63. The seat frame section 53 extends forward from the rear frame section 52 and supports the right and left sides of the seat 62, and also supports the left and right arm supports 64. The lower frame section 54 extends forward from the rear frame section 52 and supports the casters 66, etc.

[0028] The left wheel 10L and the right wheel 10R are supported by the left frame section 51L and the right frame section 51R, respectively. As shown in Figure 2, for example, a support section 52a is formed at the lower part of the rear frame section 52, protruding to the rear. The axles of the wheels 10L and 10R are supported by this support section 52a. For example, the axles are inserted into through holes formed in the support section 52a.

[0029] The frame 50 can be folded so that the distance between the left and right wheels 10L and 10R is reduced (see Figure 7).

[0030] For example, as shown in Figure 2, frame 50 has movable arms 55a and 55b that connect the left and right frame sections 51L and 51R. The two movable arms 55a and 55b are arranged to intersect and are connected to each other at their intersection via a connecting shaft. The upper ends of the two movable arms 55a and 55b are connected to the right frame section 51R and the left frame section 51L, respectively, via a connecting shaft. The lower ends of the two movable arms 55a and 55b are connected to the left frame section 51L and the right frame section 51R, respectively, via a connecting shaft. By moving the movable arms 55a and 55b so that the angle between them becomes smaller, the distance between the left and right frame sections 51L and 51R is reduced, and frame 50 can be folded.

[0031] [Battery holder] As shown in Figure 1, the battery holder 40 is positioned closer to the right wheel 10R than to the center of the electric wheelchair 100 in the left-right direction. The battery holder 40 is positioned inside the right wheel 10R (towards the center in the left-right direction) and is positioned along the right wheel 10R.

[0032] As shown in Figure 4, the battery holder 40 has a front wall portion 41 positioned along the front surface 31a of the battery 30, a rear wall portion 42 positioned along the rear surface 31b of the battery 30, and a right wall portion 43 positioned along the right side surface 31c of the battery 30. The battery holder 40 also has a bottom portion 44 that supports the bottom surface of the battery 30.

[0033] As shown in Figure 4, the battery holder 40 has a plurality of terminals 49 for electrically connecting to the battery 30. The terminals 49 are provided, for example, on the upper surface of the bottom portion 44. The terminals 49 protrude upward from the upper surface 44a of the bottom portion 44. The bottom portion 44 may house a terminal block to which the plurality of terminals 49 are attached, or cables connected to the terminal block. The battery 30 has terminal holes formed on its lower surface into which the terminals 49 are inserted.

[0034] Unlike the example shown in Figure 4, the terminal 49 may be provided on another wall of the battery holder 40. For example, the terminal 49 may be provided on the right wall 43 of the battery holder 40. In this case, a terminal for connecting to this terminal 49 may be provided on the right side surface 31c of the battery 30.

[0035] Components related to the charging and discharging of the battery 30 may be arranged on the wall portion of the battery holder 40. For example, as shown in Figure 5, a circuit board 48 may be housed in the right wall portion 43 of the battery holder 40. The circuit board 48 may have an electrical circuit for supplying power from the battery 30 to the left and right electric motors 21. The circuit board 48 may also have an electrical circuit for supplying power from the battery 30 to a control device for controlling the electric motors 21.

[0036] Furthermore, the battery holder 40 may be configured to charge the battery 30 with power supplied from an external power supply while the battery 30 is mounted in the battery holder 40. In this case, the battery holder 40 may be provided with a connector for connecting a cable extending from an external power supply. The connector may be provided, for example, on the rear wall portion 42 of the battery holder 40.

[0037] As shown in Figure 4, a retractable connector cover 42e may be attached to the rear wall portion 42 to cover the connector. Components related to the charging and discharging of the battery 30 may also be housed in this rear wall portion 42. For example, a circuit for charging the battery 30 and a heat sink 47 for cooling components mounted on the circuit may be housed in the rear wall portion 42.

[0038] [Battery holder support structure] As shown in Figure 2, the battery holder 40 is supported by a stay 71. The stay 71 is attached, for example, to the right side of the battery holder 40. More specifically, the stay 71 is attached to the right side 44c of the bottom 44.

[0039] The stay 71 has a mounting plate 71c (see Figure 2) that is attached to the right side of the bottom portion 44 by fasteners such as screws and bolts. The stay 71 also has a plurality of extensions 71a (see Figure 5) that extend to the right from the mounting plate 71c. The stay 71 has a mounting plate 71b (see Figure 5) that is fixed to the right end of the plurality of extensions 71a. The mounting plate 71b is attached to the wheel 10L by fasteners such as screws and bolts. The mounting plate 71b is fixed to the motor housing 23, for example. This structure of the battery holder 40 allows for a large distance L1 (see Figure 3) to be secured between the right wheel 10R and the battery holder 40. The battery holder 40 may be located inward (towards the center in the left-right direction) from the rear frame portion 52 of the right frame portion 51R, as shown in Figure 4.

[0040] [Battery holder shape] As shown in Figure 4, the battery holder 40 opens upwards (towards Z1 in Figure 1, etc.) of the electric wheelchair 100. The battery holder 40 also opens inwards (towards X2 in Figure 1, etc.), which is the direction towards the center of the electric wheelchair 100 in the left-right direction. In other words, the battery holder 40 opens toward the opposite side (left side) from the side to which the stay 71 is attached. The battery holder 40 does not have a left wall portion connecting the left edge of the front wall portion 41 and the left edge of the rear wall portion 42. Therefore, when the battery 30 is mounted in the battery holder 40, the left side surface 31d of the battery 30 is exposed inwards (towards X2 in Figure 1).

[0041] The structure of the battery holder 40 allows for a reduction in the width of the vehicle in the left-right direction (distance between wheels 10L and 10R) when the frame 50 is folded, without reducing the capacity of the battery 30. For example, compared to a conventional battery holder that has four walls surrounding the right, left, front, and rear sides of the bottom of the battery, the width of the vehicle when the frame 50 is folded can be reduced.

[0042] Contrary to the example shown in Figure 1, the battery holder 40 may be positioned to the left of the center of the electric wheelchair 100 in the left-right direction. That is, the battery holder 40 may be positioned along the left wheel 10L. In this case, the battery holder 40 may be formed to open upward and to the right.

[0043] The battery 30 has a left side surface 31d (see Figure 6A) that faces inward (to the left in the electric wheelchair 100). When the battery 30 is mounted in the battery holder 40, it is desirable that the entire left side surface 31d is exposed inward from the battery holder 40. More specifically, it is desirable that the battery holder 40 is configured such that the area from the lower edge 31e (see Figure 6A) to the upper edge 31f (see Figure 6A) of the left side surface 31d is exposed inward.

[0044] [Relationship between battery and battery holder] As shown in Figure 5, the width W1 in the left-right direction of the inner surface 42a of the rear wall portion 42 and the inner surface 41a of the front wall portion 41 of the battery holder 40 is smaller than the width W2 in the left-right direction of the battery body 31. Therefore, as shown in Figure 3, when the battery 30 is mounted in the battery holder 40, the battery body 31 has a portion 31g on its left side that is located to the left of the left side surface 42b of the rear wall portion 42 of the battery holder 40, the left side surface 41b of the front wall portion 41, and the left side surface 44b of the bottom portion 44. With this structure, while ensuring sufficient capacity for the battery 30, the width of the vehicle body in the left-right direction (distance between wheels 10L and 10R) when the battery 30 is removed and the frame 50 is folded, as shown in Figure 7, can be further reduced.

[0045] The width of part 31g in the left-right direction may be less than half the width of the entire battery body 31 in the left-right direction. Also, the width of part 31g in the left-right direction may be less than 1 / 3 of the width of the entire battery body 31 in the left-right direction. Also, the width of part 31g in the left-right direction may be greater than 1 / 8 of the width of the entire battery body 31 in the left-right direction. The width of part 31g in the left-right direction may be greater than 1 / 6 of the width of the entire battery body 31 in the left-right direction.

[0046] As shown in Figure 3, the left side surface 31d of the battery body 31 may have a slope 31h at its lowest point that approaches the battery holder 40 downwards. Therefore, the lowest part of the battery body 31 does not necessarily have to have a portion 31g. In other words, the portion 31g is not necessarily formed over the entire area from the top to the bottom of the battery body 31, but may be formed only in a part of the area from the top to the bottom of the battery body 31. Note that, unlike the example shown in Figure 3, the portion 31g may be formed over the entire area from the top to the bottom of the battery body 31. That is, the portion 31g does not necessarily have a slope 31h.

[0047] As shown in Figure 3, when the battery 30 and battery holder 40 are viewed in the front-to-back direction, the center C1 of the battery 30 (the center of the battery body 31) in the left-to-right direction coincides with the front wall portion 41 and the rear wall portion 42 of the battery holder 40 (in Figure 3, the symbol C1 indicates a plane passing through the center in the left-to-right direction). In other words, the center C1 of the battery 30 is located to the right of the left side surfaces 41b and 42b of the front wall portion 41 and the rear wall portion 42. This improves the support stability of the battery 30 by the battery holder 40.

[0048] Furthermore, as shown in Figure 5, when the battery 30 and battery holder 40 are viewed from above, the center C1 of the battery 30 (the center of the battery body 31) in the left-right direction may coincide with the bottom 44 of the battery holder 40. In other words, the center C1 of the battery 30 is located to the right of the left side surface 44b of the bottom 44. This improves the support stability of the battery 30 by the battery holder 40.

[0049] As shown in Figure 3, when the battery 30 and battery holder 40 are viewed in the front-rear direction, the center of gravity G1 of the battery 30 coincides with the front wall 41 and rear wall 42 of the battery holder 40. In other words, the center of gravity G1 of the battery 30 is located to the right of the left side surfaces 41b and 42b of the front wall 41 and rear wall 42. This improves the support stability of the battery 30 by the battery holder 40.

[0050] Furthermore, as shown in Figure 5, when the battery 30 and battery holder 40 are viewed from above, the center of gravity G1 of the battery 30 may coincide with the bottom 44 of the battery holder 40. In other words, the center of gravity G1 of the battery 30 is located to the right of the left side surface 44b of the bottom 44. This improves the support stability of the battery 30 by the battery holder 40.

[0051] As shown in Figure 3, the upper surfaces 41c, 42c, and 43c of the front wall 41, rear wall 42, and right wall 43 are higher than the vertical center C2 of the battery body 31. (The symbol C2 indicates a horizontal plane passing through the vertical center of the battery 30.)

[0052] [Guide Section] As shown in Figure 4, the battery holder 40 has a guide portion 45. The guide portion 45 is formed, for example, on the inner surface of the front wall portion 41 and the inner surface of the rear wall portion 42. The guide portion 45 is, for example, a groove extending in the vertical direction. On the other hand, the battery 30 has a guided portion 33 (see Figures 6A and 6B) formed on the front surface 31a and the rear surface 31b. The guided portion 33 is, for example, a convex portion extending in the vertical direction.

[0053] The guide portion 45 and the guided portion 33 engage with each other, restricting the inward movement of the battery 30 relative to the battery holder 40. In other words, it prevents the battery 30 from separating from the battery holder 40 toward the center in the left-right direction of the electric wheelchair 100. The guide portion 45 and the guided portion 33 also allow the battery 30 to move vertically relative to the battery holder 40. That is, the battery 30 can be inserted into the battery holder 40 from above.

[0054] As shown in Figure 4, a slope is formed on the upper part of the guide section 45 such that the width W3 in the left-right direction of the upper part of the guide section 45 is greater than the width in the left-right direction of the lower part of the guide section 45. This makes it easier to insert the battery holder 40 into the battery 30.

[0055] Unlike the examples shown in Figures 4 and 6A, grooves extending vertically may be formed on the front surface 31a and rear surface 31b of the battery 30 as guided portions 33. In this case, the guide portion 45 may be a protrusion extending vertically.

[0056] As shown in Figure 4, the upper surface 44a of the bottom 44 of the battery holder 40 has a slope 44i on its left edge. The slope 44i is a slope that gradually slopes downward to the left. The slope 44i continues from the front wall 41 to the rear wall 42. This slope 44i helps to prevent excessive force from being applied to the battery 30 and the left edge of the bottom 44 when the battery 30 is fitted into the battery holder 40 due to collision. It also helps to encourage moisture (e.g., rainwater) that falls inside the battery holder 40 to be discharged to the left side of the battery holder 44.

[0057] [Battery locking mechanism] A locking mechanism may be provided for the battery 30 and the battery holder 40. For example, as shown in Figure 6B, a protrusion 34a may be provided on the front surface 31a of the battery body 31, and a recess 46 (see Figure 4) may be formed in the front wall 41 of the battery holder 40 in which this protrusion 34a catches. This protrusion 34a may be connected to an operating part 34b (see Figure 6B) located on the handle 32. The operating part 34b and the protrusion 34a may be connected such that when the operating part 34b is pulled up, the protrusion 34a retracts.

[0058] As shown in Figure 4, the inner surface 43a of the right wall portion 43 of the battery holder 40 has a sloped surface 43d at its uppermost part. The sloped surface 43d extends diagonally upward and outward in the left-right direction from its lower edge. The sloped surface 43d is continuous from the front wall portion 41 to the rear wall portion 42. This sloped surface 43d allows the battery 30 to be guided to the correct position when the battery 30 is inserted into the battery holder 40 in a tilted position to the right. This makes it easier to insert the guided portion 33 into the guide portion 45.

[0059] [Space between the battery holder and the wheel] As described above, the battery holder 40 is supported by the stay 71 and is located inward (to the left) from the wheel 10R. Using the slope 43d described above, the battery 30 can be inserted into the battery holder 40 from a position closer to the right wheel 10R. At this time, the space formed between the right wheel 10R and the battery holder 40 (distance L1 shown in Figure 3) can function as space for inserting and removing the battery 30.

[0060] As described above, the electric wheelchair 100 has an arm support 64. The space between the right wheel 10R and the battery holder 40 may be used to move the arm support 64. As shown in Figure 2, a support bar 64a is attached to the arm support 64. This support bar 64a is connected to the seat frame 53 so that it can move up and down relative to the seat frame 53.

[0061] In contrast, the electric wheelchair 100 may have a movable part that supports the arm support 64. The movable part may support the arm support 64 so that the arm support 64 moves between a horizontal position (position in use) where the arm support 64 is positioned substantially horizontally, as shown in Figure 1, etc., and a vertical position where the arm support 64 is positioned substantially vertically. If the electric wheelchair 100 has such a movable part, when the arm support 64 is in the vertical position, a part of the movable part may be located in the space between the right wheel 10R and the battery holder 40.

[0062] As shown in Figure 3, the right side (outer surface) 43e of the right wall portion 43 of the battery holder 40 may have a sloped surface 43f at its uppermost part. The battery holder 40 may avoid interference with the movable part supporting the arm support 64 by having this sloped surface 43f.

[0063] [Folding electric wheelchair] The electric wheelchair 100 has a stopper portion 68b, as shown in Figure 2. The stopper portion 68b is located closer to the left wheel 10L than the center of the wheelchair 100 in the left-right direction. On the other hand, the battery holder 40 has a stoppered portion 44f (see Figure 4) on its left side. The stopper portion 68b and the stoppered portion 44f come into contact with each other when the battery 30 is removed and the electric wheelchair 100 is folded, as shown in Figure 7. This restricts the distance between the left and right wheels 10L and 10R from becoming smaller than a preset value D1. With this structure, for example, the width of the electric wheelchair 100 when folded can be reduced compared to a structure in which the stoppered portion 44f is provided on a different part from the battery holder 40.

[0064] As shown in Figure 4, the stopper portion 44f is formed, for example, on the left side surface 44b of the bottom portion 44. The bottom portion 44 has a larger width (width in the front-to-back direction) than the sides 41b and 42b of the other wall portions 41 and 42. Therefore, a wide area of ​​the stopper portion 44f can be secured. As a result, when the electric wheelchair 100 is folded, the stopper portion 68b can be reliably brought into contact with the stopper portion 44f. The bottom portion 44 has a portion at its front that extends downward compared to the rear portion. The left side surface of this front portion may function as the stopper portion 44f.

[0065] As shown in Figure 3, the left side surface 44b of the bottom portion 44, where the stopper portion 44f is formed, and the left side surface 42b of the rear wall portion 42 are located on substantially the same vertical plane. Similarly, the left side surface 44b of the bottom portion 44 and the left side surface 41b of the front wall portion 41 are located on substantially the same vertical plane. This ensures sufficient space (space for accommodating cables and terminal blocks) is formed inside the bottom portion 44. Unlike the example shown in Figure 3, the left side surface 44b of the bottom portion 44 may be recessed to the right relative to the left sides 41b and 42b of the walls 41 and 42. The stopper portion 44f may then be secured on this recessed left side surface 44b.

[0066] The stopper portion 44f may be formed on other walls of the battery holder 40. For example, the stopper portion 44f may be formed on the left side surface 41b of the front wall portion 41, or on the left side surface 42b of the rear wall portion 42.

[0067] The electric wheelchair 100 has two rear casters 67, as shown in Figure 2. The two rear casters 67 are located behind the left and right wheels 10L and 10R, respectively. The electric wheelchair 100 has a caster support mechanism 68 that supports the rear casters 67. The caster support mechanism 68 has a mounting portion 68a at its foremost end, which is attached to another part of the vehicle body. The mounting portion 68a is attached, for example, to the motor housing 23. The caster support mechanism 68 extends rearward from the mounting portion 68a and supports the casters 67 at its rearmost end.

[0068] The stopper portion 68b described above may be provided, for example, on the caster support mechanism 68. For example, the stopper portion 68b may be provided on the mounting portion 68a of the caster support mechanism 68. For example, the right side of the mounting portion 68a may function as the stopper portion 68b.

[0069] The position of the stopper portion 68b is not limited to this. For example, the stopper portion 68b may be provided on the left frame portion 51L or on the left motor housing 23.

[0070] As shown in Figure 3, when the battery body 31 is mounted in the battery holder 40, it has a portion 31g that is located to the left of the left side surface 41b of the front wall portion 41 and the left side surface 42b of the rear wall portion 42. In other words, a space S1 is secured to the left of the battery holder 40 where this portion 31g is located. As shown in Figure 7, when the battery 30 is removed from the battery holder 40 and the electric wheelchair 100 is folded, a part of the left frame portion 51L is located in front of this space S1. For example, the rear frame portion 52 of the left frame portion 51L may be located in front of this space S1.

[0071] Furthermore, as shown in Figure 7, when the battery 30 is removed from the battery holder 40 and the electric wheelchair 100 is folded, the lower part of the left frame section 51L is located in front of the battery holder 40. Therefore, in a rear view of the electric wheelchair 100, the lower part of the left frame section 51L (the lower part of the rear frame section 52) and the battery holder 40 overlap.

[0072] Furthermore, when the battery 30 is removed from the battery holder 40 and the electric wheelchair 100 is folded, a portion of the left wheel 10L (for example, the motor housing 23) may be placed in this space S1.

[0073] [summary] (1) The power unit U includes an electric motor 21 mounted on the right wheel 10R, an electric motor 21 mounted on the left wheel 10L, a battery 30 for supplying current to the electric motors 21, and a battery holder 40 that houses the battery 30 and is positioned closer to the right wheel 10R than the center of the electric wheelchair 100 in the left-right direction. The battery holder 40 is open inwards, which is the direction toward the center of the electric wheelchair 100 in the left-right direction, and upwards toward the electric wheelchair 100.

[0074] The structure of the battery holder 40 allows for a reduction in the width of the vehicle in the left-right direction (distance between wheels 10L and 10R) when the frame 50 is folded, without reducing the capacity of the battery 30. For example, compared to a conventional battery holder that has four walls surrounding the right, left, front, and rear sides of the bottom of the battery, the width of the vehicle when the frame 50 is folded can be reduced.

[0075] (2) In the power unit U described in (1), the battery 30 has a left side surface 31d that faces inward. When the battery 30 is mounted in the battery holder 40, the entire left side surface 31d is exposed inward from the battery holder 40.

[0076] (3) In the power unit U described in (1) or (2), the battery 30 has a front surface 31a facing forward of the electric wheelchair 100 and a rear surface 31b facing backward of the electric wheelchair 100. The battery holder 40 has a front wall portion 41 along the front surface 31a and a rear wall portion 42 along the rear surface 31b. The front wall portion 41 has an inner surface 41a along the front surface 31a of the battery 30. The rear wall portion 42 has an inner surface 42a along the rear surface 31b of the battery 30. The width W1 in the left-right direction of the inner surfaces 41a and 42a is smaller than the width W2 in the left-right direction of the battery 30. The capacity of the battery 30 can be increased while reducing the width of the vehicle body when the frame 50 is folded.

[0077] In the power unit U described in (4)(3), when the battery 30 and battery holder 40 are viewed in the front-rear direction, the center of gravity G1 of the battery 30 coincides with the front wall portion 41 and the rear wall portion 42. This improves the stability of the support of the battery 30.

[0078] In the power unit U described in (5)(3) or (4), when the battery 30 and battery holder 40 are viewed in the front-rear direction, the plane C1 passing through the center of the battery 30 in the left-right direction intersects the front wall portion 41 and the rear wall portion 42. This improves the stability of the support of the battery 30.

[0079] In the power unit U described in any of (6)(3) to (5), the positions of the upper surfaces 41c and 42c of the front wall portion 41 and the rear wall portion 42 are higher than the vertical center C2 of the battery 30. This improves the stability of the support for the battery 30.

[0080] In the power unit U described in any of (7)(3) to (6), the battery 30 has a left side surface 31d facing inward and a right side surface 31c facing outward, opposite to the inward direction. The battery holder 40 includes a right wall portion 43 along the right side surface 31c of the battery 30. The right wall portion 43 has an inner surface 43a facing inward. The inner surface 43a has a sloped surface 43d at its uppermost part. The sloped surface 43d extends diagonally upward and to the right from its lower edge. With this structure, when the battery 30 is inserted into the battery holder 40 in a tilted position to the right, the sloped surface 43d can guide the battery 30 to the correct position.

[0081] (8) In the power unit U described in any of (1) to (7), the battery holder 40 has a guide portion 45. The battery 30 has a guided portion 33. The guide portion 45 and the guided portion 33 allow vertical movement of the battery 30 relative to the battery holder 40 and restrict inward movement of the battery 30 relative to the battery holder 40.

[0082] (9) The electric wheelchair 100 proposed in this disclosure has a power unit U as described in any of (1) to (8) and left and right wheels 10L and 10R.

[0083] The electric wheelchair 100 described in (10)(9) has a stopper portion 68b located closer to the left wheel 10L than the center of the electric wheelchair 100 in the left-right direction. The battery holder 40 has a stoppered portion 44f. The stopper portion 68b and the stoppered portion 44f are in contact with each other when the electric wheelchair 100 is folded, and restrict the distance L1 between the right wheel 10R and the left wheel 10L from becoming smaller than a preset value. With this structure, for example, the width of the electric wheelchair 100 when folded can be reduced compared to a structure in which the stoppered portion 44f is provided on another part than the battery holder 40.

[0084] In the electric wheelchair 100 described in (11)(10), the battery holder 40 has an inwardly facing side surface 44b. The stopper portion 44f is provided on the side surface 44b.

[0085] In the electric wheelchair 100 described in (12), (10), or (11), the battery holder 40 has a bottom portion 44 that supports the lower surface of the battery 30. The stopper portion 44f is provided on the bottom portion 44. This structure allows the stopper portion 44f to be secured over a wide area. As a result, when the electric wheelchair 100 is folded, the stopper portion 68b can be reliably brought into contact with the stopper portion 44f.

[0086] In the electric wheelchair 100 described in (13)(10) to (12), the battery 30 has a front surface 31a facing forward of the electric wheelchair 100 and a rear surface 31b facing backward of the electric wheelchair 100. The battery holder 40 has a front wall portion 41 along the front surface 31a and a rear wall portion 42 along the rear surface 31b. When the battery 30 is mounted in the battery holder 40, it has a portion 31g that is located inward from the left side surfaces 41b and 42b facing inward from the front wall portion 41 and the rear wall portion 42. A space S1 is secured inward from the battery holder 40 for the portion 31g of the battery 30 to be positioned. When the electric wheelchair 100 is folded with the battery 30 removed from the battery holder 40, the left frame portion 51L closer to the left wheel 10L is located in front of the space S1.

[0087] In the electric wheelchair 100 described in (14)(9) to (13), the battery 30 has a left side surface 31d facing inward and a right side surface 31c facing outward, opposite to the inward direction. The battery holder 40 includes a right wall portion 43 along the right side surface 31c of the battery 30. The right wall portion 43 has an inner surface 43a facing the center of the electric wheelchair 100 in the left-right direction. The inner surface 43a has a slope 43d at its uppermost part, and the slope 43d extends diagonally upward and outward from its lower edge. The battery holder 40 is supported away from the right wheel 10R in the inward (leftward) direction. With this structure, the battery 30 can be inserted into the battery holder 40 from a position closer to the right wheel 10R by utilizing the slope 43d. At this time, the space formed between the right wheel 10R and the battery holder 40 can function as space for inserting and removing the battery 30.

[0088] [others] Furthermore, the power unit and electric wheelchair proposed in this disclosure are not limited to the power unit U and electric wheelchair 100 described above, and various modifications may be made.

[0089] For example, in the electric wheelchair 100, the battery body 31 has a portion 31g located to the left of the left side surfaces 41b, 42b, and 44b of the battery holder 40. However, the battery 30 does not need to have such a portion 31g. [Explanation of symbols]

[0090] 10L: Left wheel, 10R: Right wheel, 11: Hub, 21: Electric motor, 23: Motor housing, 30: Battery, 31: Battery body, 31a: Front, 31b: Rear, 31c: Right side, 31d: Left side, 31h: Sloping surface, 32: Handle, 33: Guided part, 34a: Protruding part, 34b: Operating part, 40: Battery holder, 41: Front wall, 41a: Inner surface, 41b: Left side, 41c: Top, 42: Rear wall, 42a: Inner surface, 42b: Left side, 42e: Connector cover, 43: Right wall, 43a: Inner surface, 43d: Sloping surface, 43f: Sloping surface, 44: Bottom, 44a: Top, 44b: Left side, 44c: Right side, 44f: Stoppered part 44i: Slope, 45: Guide section, 46: Recess, 47: Heat sink, 48: Circuit board, 49: Terminal, 50: Frame, 51L: Left frame section, 51R: Right frame section, 52: Rear frame section, 52a: Support section, 53: Seat frame section, 54: Lower frame section, 55a / 55b: Movable arm, 61: Foot support, 62: Seat, 63: Back support, 64: Arm support, 64a: Support bar, 66: Caster, 67: Rear caster, 68: Caster support mechanism, 68a: Mounting section, 68b: Stopper section, 71: Stay, 71a: Extension section, 71b: Mounting plate, 71c: Mounting plate, 100: Electric wheelchair.

Claims

1. A power unit mounted on an electric wheelchair that has a first wheel, which is one of the right wheel and the left wheel, and a second wheel, which is the other of the right wheel and the left wheel, and is foldable so that the distance between the first wheel and the second wheel is reduced, The first electric motor mounted on the first wheel, The second electric motor mounted on the second wheel, A battery for supplying current to the first electric motor and the second electric motor, A battery holder for housing the battery is positioned closer to the first wheel than the center in the left-right direction of the electric wheelchair. It has, The battery holder has openings inward, which is the direction towards the center of the electric wheelchair in the left-right direction, and upward, towards the electric wheelchair. The power unit for an electric wheelchair.

2. The battery has the first side surface that faces inward, When the battery is mounted in the battery holder, the entire first side surface is exposed inward from the battery holder. The power unit for an electric wheelchair.

3. The battery has a front end facing forward of the electric wheelchair and a rear end facing backward of the electric wheelchair. The battery holder has a front wall portion that runs along the front surface and a rear wall portion that runs along the rear surface. The front wall portion has a first inner surface that is aligned with the front surface of the battery. The rear wall portion has a second inner surface that is aligned with the rear surface of the battery. The width of the first inner surface and the second inner surface in the left-right direction is smaller than the width of the battery in the left-right direction. A power unit for an electric wheelchair as described in claim 1.

4. When the battery and battery holder are viewed in the front-to-back direction, the center of gravity of the battery coincides with the front wall and the rear wall. A power unit for an electric wheelchair as described in claim 3.

5. When the battery and the battery holder are viewed in the front-to-back direction, the plane passing through the center of the battery in the left-to-right direction intersects the front wall and the rear wall. A power unit for an electric wheelchair as described in claim 3.

6. The upper surfaces of the front and rear walls are positioned higher than the center of the battery in the vertical direction. A power unit for an electric wheelchair as described in claim 3.

7. The battery has a first side facing inward and a second side facing outward, which is in the opposite direction to the inward direction. The battery holder includes a side wall portion that is along the second side surface of the battery, The side wall portion has an inner surface that faces inward, The aforementioned inner surface has a slope at its uppermost part, The aforementioned slope extends diagonally upward and outward from the lower edge of the slope. A power unit for an electric wheelchair as described in claim 1.

8. The aforementioned battery holder has a guide portion, The aforementioned battery has a guided portion, The guide portion and the guided portion allow vertical movement of the battery relative to the battery holder and restrict inward movement of the battery relative to the battery holder. A power unit for an electric wheelchair as described in claim 1.

9. An electric wheelchair having the power unit described in claim 1, the first wheel, and the second wheel.

10. The electric wheelchair has a stopper portion located closer to the second wheel than the center in the left-right direction of the electric wheelchair, The aforementioned battery holder has a stopper portion, The stopper portion and the portion to be stopped are in contact with each other when the electric wheelchair is folded, and restrict the distance between the first wheel and the second wheel from becoming smaller than a preset value. The electric wheelchair described in claim 9.

11. The battery holder has the side surface facing inward, The stopper portion is provided on the side surface. The electric wheelchair as described in claim 10.

12. The battery holder has a bottom that supports the lower surface of the battery, The stopper portion is provided at the bottom. The electric wheelchair as described in claim 10.

13. The battery has a front end facing forward of the electric wheelchair and a rear end facing backward of the electric wheelchair. The battery holder has a front wall portion that runs along the front surface and a rear wall portion that runs along the rear surface. When the battery is mounted in the battery holder, it has a portion that is located inward from the inward side surfaces of the front wall and the rear wall, A space is secured in the inward direction of the battery holder where the portion of the battery is to be arranged. When the electric wheelchair is folded with the battery removed from the battery holder, the frame closer to the second wheel is located in front of the space. The electric wheelchair as described in claim 10.

14. The battery has a first side facing inward and a second side facing outward, which is in the opposite direction to the inward direction. The battery holder includes a side wall portion that is along the second side surface of the battery, The side wall portion has an inner surface facing the center in the left-right direction of the electric wheelchair, The aforementioned inner surface has a slope at its uppermost part, and the slope extends diagonally upward and outward from its lower edge. The battery holder is supported away from the first wheel in the inward direction. The electric wheelchair described in claim 9.

Images