Electric assist unit

Abstract

This electric assist unit is configured to be mounted to a manual wheelchair. The electric assist unit comprises: an electric assist device that can be mounted to the handrim of the manual wheelchair without being fixed in the circumferential direction and can be supported by an operator in the circumferential direction during electric travel; and a retaining bracket that fixes and supports the electric assist device so that the electric assist device is retained in a state of being mounted to the handrim during non-electric travel. The retaining bracket has: one or more clamps that can be mounted to a frame of the manual wheelchair; and a retaining part that retains the electric assist device. The retaining bracket is configured to be mounted on the handrim side with respect to the frame. The retaining part is located in a non-use area, which is an area located outside an area used during manual travel in the circumferential direction of the handrim, in a state where the clamps are mounted to the frame.

Description

Electric assist unit

[0001] The present invention relates to an electric assist unit attached to a manual wheelchair.

[0002] There is known an electric assist device for simply electrifying a general manual wheelchair. JP2021-514799A discloses an electric assist device that runs a manual wheelchair by rotating a friction roller that contacts the wheels of the manual wheelchair with an electric motor. In this device, the friction roller and the electric motor are supported by the frame of the manual wheelchair, and at a different position, a battery and an operation joystick are also attached to the frame of the manual wheelchair. In order to attach an electric assist device configured such that the friction roller, the electric motor, the battery, and the joystick are attached at separate positions to a manual wheelchair, relatively large-scale modification is required.

[0003] As a configuration that does not require such large-scale modification, a device in which a friction roller, an electric motor, and a battery are integrated is attached to the handrim of a manual wheelchair in a state where it is not fixed in the circumferential direction, and is supported in the circumferential direction by an operator during electric driving. In this configuration, if the driving direction and driving force are controlled according to the amount of movement or inclination when the operator moves the device back and forth along the circumferential direction of the handrim, a joystick is also unnecessary.

[0004] However, in the integrated device as described above, the operator needs to always hold the electric assist device, and when manual driving or direction change is desired, the integrated device needs to be removed from the manual wheelchair. In this case, there is a risk of trouble regarding the storage location of the removed device.

[0005] Therefore, an object of the present invention is to provide an electric assist unit that does not require large-scale modification for attachment to a manual wheelchair and does not need to be removed from the manual wheelchair when manually driving or the like.

[0006] According to one aspect of the present invention, an electric assist unit for attachment to a manual wheelchair is provided. This unit comprises an electric assist device that is mounted on the handrim of the manual wheelchair in a manner that is not fixed in the circumferential direction and is supported in the circumferential direction by the operator during electric operation, and a fixed support bracket that holds the electric assist device in place while it is mounted on the handrim during non-electric operation. The retaining bracket has one or more clamps that are attached to the frame and a retaining portion for holding the electric assist device, and is attached to the handrim side of the frame of the manual wheelchair. The retaining portion is located in a non-use area, which is an area outside the area used during manual operation in the circumferential direction of the handrim, when the clamps are attached to the frame.

[0007] Figure 1 is a side view showing the electric assist unit mounted on a manual wheelchair. Figure 2 is a side view showing the electric assist device mounted on the wheels of the manual wheelchair. Figure 3 is a top view of the same. Figure 4 is a front view of the same. Figure 5 is an enlarged side view of the main part of Figure 2. Figure 6 is an enlarged side view of the main part of Figure 4. Figure 7 is a perspective view showing the mounting bracket mounted on a manual wheelchair. Figure 8 is a perspective view of the mounting bracket. Figure 9 is an enlarged view of the area around the mounting part of the mounting bracket. Figure 10 is a perspective view showing the electric assist device mounted on the mounting part. Figure 11 is an example of a side view and front view of the mounting bracket according to the first modification. Figure 12 is another example of a side view and front view of the mounting bracket according to the first modification. Figure 13 is an example of a side view and front view of the mounting bracket according to the second modification. Figure 14 is a side view showing the electric assist unit according to the third modification mounted on a manual wheelchair. Figure 15 is a side view showing the electric assist unit according to the fourth modification attached to a manual wheelchair. Figure 16 is a side view showing the electric assist unit according to the fifth modification attached to a manual wheelchair.

[0008] Embodiments of the present invention will be described below with reference to the drawings.

[0009] Figure 1 is a side view showing the electric assist unit according to this embodiment attached to a manual wheelchair (hereinafter also simply referred to as "wheelchair") 100. Figure 1 shows the frame 9 as viewed from the side where the seat 28 and backrest 29 are provided. In the following description, following the concepts of front-to-back, left-to-right, and up-and-down of the wheelchair 100, the X direction shown in Figure 1 will be referred to as the front-to-back direction, the Y direction as the left-to-right direction or width direction, and the Z direction as the up-and-down direction.

[0010] [Manual Wheelchair] The wheelchair 100 has a conventionally known general configuration, with a seat 28 on which the user (operator) sits and a backrest 29 on which the operator can lean between a pair of frames 9.

[0011] The frame 9 is made of metals such as aluminum, steel, stainless steel, and titanium, or carbon. The seat 28 and backrest 29 are made of fabric or resin. The wheelchair 100 can be folded when not in use by moving the pair of frames 9 closer together while deforming the seat 28 and backrest 29.

[0012] A wheel 2 is supported on the frame 9 so as to be rotatable around the axle 3, and a handrim 5 is provided on the side of the wheel 2 opposite to the frame 9 (hereinafter also referred to as the "outside") for the user to rotate the wheel 2 by hand. The handrim 5 is constructed by connecting metal tubes or metal rods with a circular cross-section in a ring shape, and is positioned slightly outside the wheel 2 and parallel to the wheel 2, and has a diameter slightly smaller than the outer diameter of the wheel 2. It is fixed to the wheel 2 via a plurality of connecting pieces 6 (see Figure 3) provided at the same angular interval.

[0013] Furthermore, a caster 7 smaller in diameter than the wheel 2 is provided in front of the wheel 2 of the frame 9, and a handle 8 extending towards the rear is provided above the backrest 29. In addition to the above-mentioned parts, the frame 9 is also fitted with armrests, footrests, and brake levers, but these are omitted in Figure 1. In the following description, the part of the frame 9 that supports the seat 28 may be referred to as the seat frame 9A, and the part that supports the backrest 29 may be referred to as the backrest frame 9B.

[0014] [Electric Assist Unit] The electric assist unit comprises an electric assist device 1 attached to the handrim 5 and configured to drive the adjacent wheel 2, and a retaining bracket 4 for storing the electric assist device 1 when not in use.

[0015] [Electric Assist Device] First, the electric assist device 1 will be described. Figures 2 to 4 show the electric assist device 1 according to this embodiment attached to the wheelchair 100. Note that only the wheels 2 of the wheelchair 100 are shown in Figures 2 to 4. Figure 5 is an enlarged front view of the main part of Figure 2, and Figure 6 is an enlarged side view of the main part of Figure 4.

[0016] The electric assist device 1 is provided on each of the left and right wheels 2. The figure illustrates the electric assist device 1 for the right wheel 2, and the electric assist device 1 for the left wheel 2 has a symmetrical shape. Here, the electric assist devices 1 provided on the left and right are not fixed in the circumferential direction when mounted on the handrim 5, and are configured so that the user seated on the seat 28 supports the electric assist devices 1 in the circumferential direction with both hands. In other words, the user bears the reaction force that acts on the electric assist device 1 when it drives the wheel 2. Figures 2 to 4 show the electric assist device 1 at the top of the wheel 2, assuming that the user is supporting it with their hands. Note that, as described above, the electric assist device 1 in this embodiment is not fixed in the circumferential direction when mounted on the handrim 5, and only needs to be configured so that the user supports it in the circumferential direction, and the configuration described below is merely an example.

[0017] As shown in Figures 5 and 6, the electric assist device 1 comprises a mounting bracket 11 for attaching the entire electric assist device 1 to the handrim 5, a drive unit 12 for driving the wheel 2, and a battery unit 13 that serves as a power source, and these three components are integrated into a single unit. The drive unit 12 has a drive unit housing 31 made of rigid synthetic resin as its first housing. The drive unit housing 31 is a rectangular box shape with relatively similar dimensions in the front-rear direction and left-right direction, and is located on the outer circumference side of the handrim 5. The battery unit 13 has a battery unit housing 32, also made of rigid synthetic resin, as its second housing. The battery unit housing 32 is an elongated box shape in the front-rear direction, and is located on the inner circumference side of the handrim 5.

[0018] The mounting bracket 11 is mainly composed of a tubular section with a circular cross-section that forms a hollow passage 15 curved in an arc shape through which the handrim 5 can pass. The tubular section is made of a hard synthetic resin with appropriate elasticity and extends forward and backward while curving in an arc shape with a curvature corresponding to the curvature of the handrim 5, and has a roughly C-shaped cross-section with an open side portion facing the wheel 2. Because the tubular section has a roughly C-shaped cross-section, it is possible to press-fit the tubular section into the handrim 5 by utilizing the elasticity of the resin material. In the pressed-fit state, the opening width of the side portion is smaller than the pipe diameter of the handrim 5. Therefore, the mounting bracket 11 will not fall off the handrim 5 naturally. The inner diameter of the tubular section with a roughly C-shaped cross-section, that is, the diameter of the hollow passage 15, is set to be slightly larger than the pipe diameter of the handrim 5, so that the handrim 5 can pass through the hollow passage 15 in the circumferential direction. In other words, the mounting bracket 11 is configured to move freely in the circumferential direction relative to the handrim 5.

[0019] A notch is provided over a relatively large length in the center of the tubular section in the longitudinal direction (front-to-back direction) to avoid interference with the drive unit housing 31. Within the range of this notch, the tubular section has a shape in which the upper part is cut off, leaving only the lower part (inner circumference) of the C-shaped cross-section. The range of this notch roughly corresponds to the front-to-back dimension of the drive unit housing 31. By providing this notch, the part that is pressed into the handrim 5 is divided into two parts, making it easier to press it into the handrim 5 and reducing the sliding resistance that occurs between the drive unit 12 and the handrim 5 during driving. In addition, it becomes possible to lower the height position of the drive unit 12.

[0020] A pair of drive unit mounting portions 18 for supporting the drive unit 12 are provided at positions adjacent to the front and rear ends of the notch in the tubular portion. Each drive unit mounting portion 18 is equipped with a circular shaft support hole 20, and each of the pair of front and rear cylindrical boss portions 33 (see Figure 6) formed in the drive unit housing 31 is configured to fit into the shaft support hole 20 of the pair of drive unit mounting portions 18. Specifically, each drive unit mounting portion 18 is composed of a fixing piece molded integrally with the tubular portion and a cap 18b fixed to this fixing piece by a screw 19. The boss portion 33 is fixed by adjusting the angle of the drive unit 12 relative to the mounting bracket 11 and then tightening the screw 19. In other words, the inner diameter of the shaft support hole 20 is slightly smaller than the outer diameter of the boss portion 33. The pair of boss portions 33 and the corresponding pair of shaft support holes 20 are configured around a single common center line along the tangential direction of the handrim 5. Therefore, when the screw 19 is loosened, the angle of the drive unit 12 can be adjusted with the above center line as the center of rotation.

[0021] The drive unit 12 has a configuration in which a pair of electric motors 35, a drive roller 36, and a reduction gear between them are housed in the drive unit housing 31. The pair of electric motors 35 are arranged in a front-to-back arrangement, and one drive roller 36 rotates via a reduction gear consisting of the pinions of each electric motor 35 and a relatively large-diameter gear on the drive roller 36 side. The drive roller 36 is in contact with the outer circumferential surface of the wheel 2, thereby transmitting rotational torque from the drive roller 36 to the wheel 2. As described above, the drive unit 12 is supported with respect to the mounting bracket 11 in a manner that allows for angle adjustment, so by adjusting the angle in accordance with the actual position of the outer circumferential surface of the wheel 2 relative to the handrim 5, it is possible to reliably ensure that the drive roller 36 is in contact with the outer circumferential surface of the wheel 2.

[0022] The drive roller 36 is made of hard synthetic resin or metal, and its outer surface is treated with an appropriate anti-slip finish. The drive roller 36 is rotatably supported at both ends of its rotating shaft by the drive unit housing 31 via bearing members.

[0023] The uppermost part of the drive unit housing 31 covering the drive roller 36 has a generally flat shape that follows the horizontal plane, and a part of the front end of the drive unit housing 31 protrudes forward from the drive roller 36, forming a grip 31a that is easy for the user to hold. An operation switch 38 is provided on the side of the grip 31a. In one embodiment, the operation switch 38 is of the push-button type and is positioned so that it can be pressed with the thumb of the hand placed on the grip 31a. The drive unit 12 is also equipped with a gravity sensor (not shown) at an appropriate position for switching between forward and reverse. Note that the position of the gravity sensor may be any other position on the electric assist device 1 other than the drive unit 12.

[0024] The battery unit housing 32 (battery cover 41) has two projections 42 that extend long in the front-to-back direction at its bottom. These two projections 42 allow the electric assist device 1, which has been removed from the wheelchair 100, to stand upright on the floor without tipping over.

[0025] The mounting bracket 11 and the battery unit housing 32 are connected to each other via a pair of rail sections 44 so as to be slidable in the left-right direction (i.e., in the axial direction of the wheel 2). The rail section 44 consists of a convex rail section 44a molded as part of a synthetic resin molded product on the battery unit housing 32 side to form a substantially T-shape in cross-section, and a concave rail section 44b having a substantially T-shaped groove that slidably engages with the convex rail section 44a. The concave rail section 44b is formed integrally with the tubular portion of the mounting bracket 11 and is formed as a highly rigid part that is thicker than the wall thickness of the annular portion. The pair of rail sections 44 are located in front of and behind, respectively, a pair of drive unit mounting sections 18 that support the drive unit housing 31. The mounting bracket 11 and the battery unit housing 32 do not interfere with each other in areas other than the pair of rail sections 44.

[0026] Next, the operation of a manual wheelchair equipped with the above-mentioned electric assist device 1 will be described. As mentioned above, the electric assist device 1 is attached to each of the left and right wheels 2 of the manual wheelchair, and is operated by a user seated in the seat with both hands placed on the left and right electric assist devices 1. For example, with the top of the wheel 2 as the reference position, when the user presses the operation switch 38 and tilts the electric assist device 1 forward, the drive roller 36 of the drive unit 12 drives the wheel 2 in the forward direction. If the left and right electric assist devices 1 are operated in the same way, the manual wheelchair will move forward. The fact that the electric assist device 1 has been tilted forward by the user is detected by a gravity sensor (for example, a 6-axis gravity sensor) built into the drive unit 12. Conversely, when the user presses the operation switch 38 and tilts the electric assist device 1 backward, the wheel 2 is driven in the reverse direction. Therefore, if the left and right electric assist devices 1 are tilted backward simultaneously, the manual wheelchair will move backward. Furthermore, by operating one of the left and right electric assist devices 1 in the forward direction and the other in the reverse direction, the manual wheelchair can be turned around.

[0027] As described above, forward and backward movement and direction changes can be performed by operating the electric assist device 1, so there is no need to provide a separate control unit such as a joystick.

[0028] In the above explanation, the uppermost part of the wheel 2 was described as the reference position of the electric assist device 1. However, it is also possible to set a reference position at an angle other than the uppermost part (an angle tilted at an appropriate angle forward or backward). Even if the reference position is set at an appropriate angle, the gravity sensor can detect whether the electric assist device 1 has been tilted forward or backward from this reference position. Furthermore, the amount of displacement of the electric assist device 1 due to user operation (how much it has been tilted) can also be detected by the gravity sensor, and in one embodiment, the larger this displacement, the greater the torque with which the wheel 2 is driven.

[0029] [Residing Bracket] Next, the retaining bracket 4 will be described with reference to Figures 7 to 10. Figures 7 and 9 show the retaining bracket 4 according to this embodiment attached to the wheelchair 100. Note that in Figures 7 and 9, only the seat frame 9A, backrest frame 9B, wheels 2 and handrims 5 of the wheelchair 100 are shown. Figure 8 is a perspective view of the retaining bracket 4. Figure 10 shows the electric assist device 1 attached to the retaining bracket 4.

[0030] The retaining bracket 4 is attached to the handrim 5 side of the frame 9. The retaining bracket 4 comprises clamps 21B and 21C that are attached to the frame 9, and a retaining section 22A for retaining the electric assist device 1.

[0031] This section describes a configuration with two clamps: a first clamp 21B attached to the seat frame 9A and a second clamp 21C attached to the backrest frame 9B. However, the number of clamps is not limited to these; there may be just one or three or more.

[0032] The first clamp 21B and the second clamp 21C are made of rigid synthetic resin and are mounted on a clamp base 21 made of rigid synthetic resin or metal. The first clamp 21B and the second clamp 21C are molded separately from the clamp base 21 and are fixed to the clamp base 21 with screws or the like. If the clamp base 21 is made of rigid synthetic resin, the first clamp 21B and the second clamp 21C and the clamp base 21 may be molded as a single unit.

[0033] The clamps 21B and 21C have a roughly C-shaped cross-section with an open side portion facing the frame. This design allows the clamps 21B and 21C to be press-fitted into the frame 9 by utilizing the elasticity of the resin material. When press-fitted, the opening width of the side portion is smaller than the pipe diameter of the frame 9. Therefore, the retaining bracket 4 will not fall out of the frame 9 naturally. The inner diameter of the roughly C-shaped clamps 21B and 21C is set to be approximately the same as the pipe diameter of the frame 9. This helps to suppress rattling of the retaining bracket 4.

[0034] The retaining portion 22A is provided at one end of the arm member 22. The one end referred to here is the radially outer end of the wheel 2 and handrim 5 when the retaining bracket 4 is attached to the frame 9. The arm member 22 and the retaining portion 22A may be molded integrally, or they may be molded as separate members and then joined together. As shown in Figures 1 and 9, with the retaining bracket 4 attached to the wheelchair 100, the retaining portion 22A is located in a non-use area that is outside the area used during manual operation (the "self-propelled use area" in Figure 1) in the circumferential direction of the handrim 5. The non-use area is the area lower than the seat 28 in the vertical direction of the wheelchair 100, or the area behind the backrest 29 in the front-rear direction of the wheelchair 100. In this embodiment, the retaining portion 22A is located in the area behind the backrest 29 in the front-rear direction of the wheelchair 100.

[0035] As shown in Figure 9, the retaining section 22A comprises a bottom portion 25 shaped to conform to the outer circumference of the wheel 2 of the wheelchair 100, and a wall portion 26 extending radially from the rear end of the bottom portion 25 in the front-rear direction to the wheel 2. As shown in Figure 10, the electric assist device 1 moves along the handrim 5 from the front in the front-rear direction, and the grip 31a of the drive unit housing 31 rides up onto the bottom portion 25, and the grip 31a comes into contact with the wall portion 26, thereby being retained in the retaining section 22A. As shown in Figure 9, a claw portion 27 protruding to the front in the front-rear direction may be provided at the upper end of the wall portion 26. Providing a receiving portion on the drive unit housing 31 that engages with the claw portion 27 makes it easier to maintain the retained state.

[0036] As described above, the electric assist device 1 is not fixed in the circumferential direction when attached to the handrim 5 of the wheelchair 100, so it becomes unstable when the user lets go. However, it is inconvenient to attach and detach the electric assist device 1 every time there is an opportunity to let go, such as when manually propelling the wheelchair or when the user wants to use their hands for some task. Furthermore, finding a place to store the removed electric assist device 1 is also a problem.

[0037] In this respect, if a retaining section 22A is provided as in this embodiment, when releasing the hand, the electric assist device 1 only needs to be moved along the handrim 5 to the retaining section 22A. Furthermore, because the retaining section 22A is located in the above area, the electric assist device 1, which is retained in the retaining section 22A, does not get in the way when manually driving.

[0038] The above effects can be obtained similarly even when the clamps 21B, 21C, clamp base 21, arm member 22, and retaining portion 22A are integrally molded. However, if they are integrally molded, the positional relationship between the clamps 21B, 21C and the retaining portion 22A is fixed, making it unusable when the diameter of the wheel 2 is different, etc. Furthermore, it is necessary to consider manufacturing tolerances for each part. Therefore, in this embodiment, in order to provide an adjustment mechanism for adjusting the radial position of the retaining portion 22A, the clamp base 21 equipped with the clamps 21B, 21C and the arm member 22 equipped with the retaining portion 22A are constructed as separate components.

[0039] The adjustment mechanism of this embodiment includes a radially elongated slot 23 provided in the clamp base 21, and a screw 24 inserted through this slot from the clamp base 21 side. This allows the position of the screw hole in the arm member 22 to be adjusted radially along the slot 23, making it possible to position the mounting portion 22A in an appropriate location according to the dimensions of the wheelchair 100 to be mounted. Note that the adjustment mechanism is not limited to the above configuration. For example, instead of the screw 24, a stud bolt may be provided in the arm member 22, and a nut may be tightened with the stud bolt inserted through the slot.

[0040] Alternatively, the bottom portion 25 may be configured such that the drive roller 36 is separated from the wheel 2 when the electric assist device 1 is mounted on the bottom portion 25. This prevents the drive roller 36 from becoming a driving resistance when manually operated.

[0041] Next, modifications of the above embodiments will be described. Each of the following modifications also falls within the technical scope of the present invention, similar to the above embodiments. Furthermore, it is possible to combine the above embodiments with each of the modifications as appropriate.

[0042] [First Modification] A first modification of the retaining bracket 4 will be described with reference to Figures 11 and 12. In both Figures 11 and 12, the left figure is a side view of the retaining bracket 4, and the right figure is a front view of the retaining bracket 4. The difference between Figure 11 and Figure 12 is the configuration of the adjustment mechanism for adjusting the position of the retaining portion 22A, specifically the dimensions of the first link 45 and the second link 46, which will be described later.

[0043] In this modified example, the retaining bracket 4 has an arm member 22 that is divided into a first arm member 22B and a second arm member 22C, with a retaining portion 22A provided on the first arm member 22B. The first arm member 22B and the second arm member 22C are connected via a first link 45 and a second link 46.

[0044] The first link 45 and the second link 46 are arranged in parallel. In FIGS. 11 and 12, the first link 45 is substantially H-shaped in side view, but it is not limited to this. The same applies to the second link 46. Also, for the connection between the first link 45 and the second link 46 and the first arm member 22B and the second arm member 22C, a known connection method can be applied. For example, fastening members such as screws may be used, or so-called insertion joints may be used.

[0045] In this modification, for each of the first link 45 and the second link 46, a plurality of links with different radial dimensions are prepared. The radial direction here refers to the radial direction of the wheel 2 in the state of being mounted on the wheelchair 100.

[0046] Then, the first link 45 and the second link 46 with appropriate dimensions are selected and used according to the wheelchair 100 to be mounted.

[0047] FIG. 11 shows the retaining bracket 4 when mounted on a certain wheelchair 100. When the lower end of the retaining bracket 4 in this case and the portion closest to the wheel 2 is defined as the reference position O, and the upper end of the retaining portion 22A and the portion closest to the wheel 2 is defined as the upper end position P1, the upper end position P1 is at a position where the axial distance from the reference position O is A1 and the radial distance is D1.

[0048] FIG. 12 shows the retaining bracket 4 when the first link 45 and the second link 46 with dimensions different from those in FIG. 11 are used. The first link 45 and the second link 46 in FIG. 12 have shorter radial dimensions than those in FIG. 11. Therefore, the upper end position P2 is at a position where the axial distance from the reference position O is A2, which is shorter than A1, and the radial distance is D2, which is shorter than D1. That is, in the configuration of FIG. 12, compared with the configuration of FIG. 11, the upper end position is closer to the axle 3 both in the axial direction and the radial direction.

[0049] As described above, the retaining bracket 4 of this modified example allows the axial and radial positions of the retaining portion 22A to be changed by changing the combination of the first link 45 and the second link 46. In other words, by changing the combination of the first link 45 and the second link 46, it can accommodate different types of wheelchairs and wheels 2 of different diameters. The axial direction referred to here is the axial direction of the wheel 2 when it is attached to the wheelchair 100.

[0050] [Second Modification] A second modification of the implantation bracket 4 will be described with reference to Figure 13. Figure 13 is a perspective view of the implantation bracket 4 according to this modification.

[0051] In this modified example, the retaining bracket 4 has a base arm 50 in which the clamp base 21 and arm member 22 in the above embodiment are integrated, and the first clamp 21B, second clamp 21C, and retaining portion 22A are separate components.

[0052] The first clamp 21B and the second clamp 21C are fixed to the base arm 50 using fastening members such as screws. The retaining portion 22A and the base arm 50 are joined, for example, by a push-fit joint.

[0053] According to the above configuration, the radial and axial positions of the mounting portion 22A can be changed by changing the shape of the base arm 50. Therefore, multiple base arms 50 with different shapes are prepared, and the appropriate base arm 50 is selected according to the wheelchair 100 to be mounted. This makes it possible to accommodate different types of wheelchairs and wheels 2 of different diameters, similar to the first modified example.

[0054] [Third Modification] A third modification of this embodiment will be described with reference to Figure 14. Figure 14 is a side view showing the electric assist unit according to this modification attached to the wheelchair 100.

[0055] In this modified electric assist unit, the side guard 51 for preventing entanglement, which is positioned between the frame 9 and the wheel 2, is integrated with the retaining bracket 4. The side guard 51 is fixed to a suitable location on the frame 9. For example, as shown in Figure 14, it may be fixed to the seat frame 9A by providing a third clamp 21D near the front end of the side guard 51 in the front-rear direction. Note that fixing points using screws (not shown) may also be provided.

[0056] With the above configuration, the retaining bracket 4 is not only fixed to the frame 9 by the first clamp 21B and the second clamp 21C, but the integrated side guard 51 is also fixed to the frame 9. This makes the attachment state of the retaining bracket 4 to the wheelchair 100 more stable.

[0057] [Fourth Modification] A fourth modification of this embodiment will be described with reference to Figure 15. Figure 15 is a side view showing the electric assist unit according to this modification attached to a wheelchair 100. Figure 15 shows the frame 9 as viewed from the side on which the wheels 2 are provided. The electric assist unit according to this modification is basically the same as the electric assist unit according to the embodiment described above, the only difference between the two is the presence or absence of the handle portion 52.

[0058] The modified electric assist unit is provided with a handle portion 52 on the side of the electric assist device 1 closest to the user in the circumferential direction when the electric assist device 1 is placed in the retaining portion 22A, for the user to grip when pulling the electric assist device 1 out of the retaining portion 22A. The side of the electric assist device 1 closest to the user in the circumferential direction when it is placed in the retaining portion 22A is, in the case of Figure 15, either the front side of the electric assist device 1 in the front-rear direction, for example, the upper surface of the tubular portion 16, and if the retaining portion 22A is in a region below the seat 28, it is the upper surface of the tubular portion 16 on the opposite side.

[0059] The handle portion 52 may be molded integrally with the components of the electric assist device 1, or it may be molded separately and attached. Furthermore, the material and shape of the handle portion 52 are not particularly limited; for example, it may be a resin hook or ring shape, or it may be a ring-shaped piece of string, cloth, leather, etc.

[0060] As described above, by providing the handle portion 52, it becomes easier to remove the electric assist device 1 that is stored in the storage portion 22A.

[0061] [Fifth Modification] A fifth modification of this embodiment will be described with reference to Figure 16. Figure 16 shows the implantation bracket 4 according to this modification attached to the wheelchair 100.

[0062] The retaining bracket 4 according to this modified example has basically the same configuration as the retaining bracket 4 according to the above embodiment, but differs in that it is equipped with a brush 53.

[0063] The brush 53 is positioned on the retaining portion 22A so as to be in contact with the wheel 2 at a location opposite to the ground contact surface of the wheel 2. For example, as shown in Figure 16, it is provided on the surface of the bottom portion 25 that faces the wheel 2.

[0064] As a result, foreign matter adhering to the wheel 2 is removed by the brush 53, making it possible to transmit driving force from the electric assist device 1 to the wheel 2 more stably.

[0065] [Sixth Modification] As described above, the electric assist device 1 integrates the drive unit 12 and the battery unit 13, and the electric assist device 1 itself also functions as the operating unit. However, there are cases where it is not possible to operate the electric assist device 1 with both hands, such as when carrying luggage.

[0066] Therefore, in this modified example, a fixing part is provided for fixing the electric assist device 1 to the retaining bracket 4 while it is retained in the retaining part 22A, and an operating part (not shown) separate from the electric assist device 1 is provided for operating the electric assist device 1 while it is retained in the retaining bracket 4.

[0067] The fixing part only needs to be capable of securing the electric assist device 1 so that it does not come off the retaining part 22A due to the reaction force from the wheel 2 when the drive roller 36 is driven by the electric motor 35, and its configuration and shape are not particularly limited. For example, the grip 31a has a receiving part that engages with the claw part 27, and once the claw part 27, which serves as the fixing part, engages with the receiving part, the engagement cannot be released unless a release operation is performed.

[0068] For the control unit, for example, a joystick commonly used in electric wheelchairs can be used.

[0069] With the above configuration, electric-powered driving using the electric assist device 1 becomes possible even when it is difficult to operate with both hands.

[0070] As described above, this embodiment provides an electric assist unit that can be attached to a manual wheelchair 100. This electric assist unit comprises an electric assist device 1 that is attached to the handrim 5 of the manual wheelchair 100 in a state that is not fixed in the circumferential direction and is supported in the circumferential direction by the user (operator) when the wheelchair is electrically driven, and a fixing support bracket 4 that keeps the electric assist device 1 attached to the handrim 5 when the wheelchair is not electrically driven. The fixing bracket 4 has one or more clamps 21B, 21C that are attached to the frame 9 and a fixing part 22A for fixing the electric assist device 1, and is attached to the handrim 5 side of the frame 9 of the manual wheelchair 100. The fixing part 22A is located in a non-use area that is outside the area used when manually driven in the circumferential direction of the handrim 5 when the clamps 21B, 21C are attached to the frame 9. As a result, an electric assist unit is provided that does not require major modifications to be attached to the manual wheelchair 100 and does not need to be removed from the manual wheelchair when manually driven. Furthermore, since the electric assist device 1 is placed in an unused area, it does not interfere with manual operation. In addition, since the mounting bracket 4 is attached to the handrim 5 side of the frame 9, it does not get in the way when folding the manual wheelchair 100.

[0071] In this embodiment, the electric assist device 1 includes a mounting bracket 11 that is attached to the handrim 5 in a state in which the handrim 5 is slidably fitted into the hollow passage portion 15, which is curved in an arc shape through which the handrim 5 can pass; a drive unit 12 that includes a drive roller 36 that contacts the outer circumferential surface of the wheel 2 and an electric motor 35 that drives the drive roller 36, which is supported by the mounting bracket 11; and a battery unit 13 that houses a battery 39, which is supported by the mounting bracket 11 and includes a battery unit housing 32 32. As a result, the installation of the electric assist device 1 is completed simply by attaching the mounting bracket 11 to the handrim 5 of the manual wheelchair 100, so that the manual wheelchair 100 can be easily electrified.

[0072] In this embodiment, the unused area is the area below the seat (seat surface) 28 in the vertical direction of the manual wheelchair 100, or the area behind the backrest 29 in the front-to-back direction of the manual wheelchair 100. This makes it possible to more reliably avoid the electric assist device 1 getting in the way when manually operating the wheelchair.

[0073] In this embodiment, the mounting bracket 4 is composed of multiple components, with the clamps 21B and 21C and the mounting portion 22A being separate components. This allows the bracket to be attached to different types of manual wheelchairs 100 by replacing the clamps 21B and 21C with ones of different dimensions.

[0074] In this embodiment, the retaining bracket 4 has an adjustment mechanism that allows the position of the retaining portion 22A to be adjusted. The adjustment mechanism is provided in at least one of the connecting portions that connect the multiple members and comprises an elongated hole 23 that is radially long in the handrim 5, and a screw (fastening member) 24 that is inserted through the elongated hole. This makes it possible to adjust the radial position of the retaining portion 22A, so that it can be attached to manual wheelchairs 100 with different diameter wheels 2.

[0075] In this embodiment, the adjustment mechanism may be configured to include two link members 45 and 46 arranged in parallel between the member on which the retaining portion 22A is provided and other members. By providing link members 45 and 46 of different dimensions and changing their combination, the radial and axial positions of the retaining portion 22A can be adjusted. This makes it possible to attach the device to various manual wheelchairs 100.

[0076] In this embodiment, the retaining section 22A is equipped with a brush 53 that contacts the wheel 2 at a position opposite to the contact surface of the wheel 2 of the manual wheelchair 100. As a result, foreign matter adhering to the wheel 2 is removed by the brush 53, making it possible to transmit driving force from the electric assist device 1 to the wheel 2 more stably.

[0077] In this embodiment, the side guard 51 for preventing entanglement, which is positioned between the frame 9 and the wheels 2 of the manual wheelchair 100, and the fixing bracket 4 are integrated. This makes the mounting state of the fixing bracket 4 to the wheelchair 100 more stable.

[0078] In this embodiment, the electric assist device 1 is provided with a handle portion 52 on the side of the device closest to the user (operator) in the circumferential direction when it is placed in the storage portion 22A, for the user (operator) to grip when pulling the electric assist device 1 out of the storage portion 22A. This makes it easier to remove the electric assist device 1 from the storage portion 22A when switching from manual to electric operation.

[0079] In this embodiment, the vehicle further includes a fixing part for securing the electric assist device 1 to the fixing bracket 4 while it is fixed to the fixing part 22A, and a separate operating part for operating the electric assist device 1 while it is fixed to the fixing bracket 4. This makes it possible to drive electrically even when it is not possible to operate the electric assist device 1 with both hands.

[0080] In this embodiment, the restraining section 22A includes a bottom portion 25 shaped to conform to the outer circumference of the wheel 2 of the manual wheelchair 100, and a wall portion 26 extending radially from one circumferential end of the bottom portion 25 toward the wheel 2. The electric assist device 1 is positioned in the restraining section 22A with the housing 31 mounted on the bottom portion 25 until it contacts the wall portion 26 from the circumferential end opposite to the circumferential end where the wall portion 26 is provided, thereby separating the drive roller 36 that contacts the wheel 2 during use from the wheel 2. This prevents the drive roller 36 from becoming a driving resistance during manual operation.

[0081] Although embodiments of the present invention have been described above, these embodiments only represent a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

Claims

1. An electric assist unit to be attached to a manual wheelchair, comprising: an electric assist device that is attached to the handrim of the manual wheelchair in a manner that is not fixed in the circumferential direction and is supported in the circumferential direction by the operator when the wheelchair is electrically driven; and a fixing support bracket that holds the electric assist device in place when the wheelchair is not electrically driven, wherein the fixing bracket comprises one or more clamps that are attached to the frame of the manual wheelchair, and a fixing portion for fixing the electric assist device, and is attached to the frame on the handrim side, and the fixing portion is located in a non-use area that is outside the area used during manual driving in the circumferential direction of the handrim when the clamps are attached to the frame.

2. An electric assist unit according to claim 1, wherein the electric assist device comprises: a mounting bracket attached to the handrim having a hollow passage portion curved in an arc shape through which the handrim can pass, and the handrim being slidably fitted into the hollow passage portion; a drive unit having a first housing supported by the mounting bracket, and including a drive roller that contacts the outer circumferential surface of the wheel and an electric motor that drives the drive roller; and a battery unit having a second housing supported by the mounting bracket, and housing a battery.

3. An electric assist unit according to claim 1, wherein the unused area is an area lower than the seat in the vertical direction of the manual wheelchair, or an area behind the backrest in the front-to-back direction of the manual wheelchair.

4. An electric assist unit according to claim 1, wherein the retaining bracket is composed of a plurality of members, and the clamp and the retaining portion are separate members.

5. An electric assist unit according to claim 4, wherein the retaining bracket has an adjustment mechanism that can adjust the position of the retaining portion, and the adjustment mechanism is provided in at least one of the connecting portions that connect the plurality of members and comprises an elongated hole that is radially long in the handrim and a fastening member that is inserted through the elongated hole.

6. An electric assist unit according to claim 4, wherein the retaining bracket has an adjustment mechanism that can adjust the position of the retaining portion, and the adjustment mechanism comprises two link members arranged in parallel between the member on which the retaining portion is provided and another member.

7. An electric assist unit according to claim 1, wherein the retaining portion is provided with a brush that contacts the wheel at a position opposite to the contact surface of the wheel of the manual wheelchair.

8. An electric assist unit according to claim 1, wherein the side guard for preventing entanglement, which is disposed between the frame and the wheels of the manual wheelchair, and the fixing bracket are integrated into one unit.

9. An electric assist unit according to claim 1, wherein the electric assist device is provided with a handle portion on the side of the circumferential direction closest to the operator when the electric assist device is placed in the retaining portion, for the operator to place their fingers on when pulling the electric assist device out of the retaining portion.

10. An electric assist unit according to claim 1, further comprising: a fixing part for fixing the electric assist device to the fixing bracket while the electric assist device is fixed to the fixing part; and an operating part separate from the electric assist device for operating the electric assist device while it is fixed to the fixing bracket.

11. An electric assist unit according to claim 1, wherein the retaining portion comprises a bottom portion shaped to conform to the outer circumference of the wheel of the manual wheelchair, and a wall portion extending radially from one circumferential end of the bottom portion, and the electric assist device is an electric assist unit in which the housing rides up onto the bottom portion from the circumferential end opposite to the circumferential end on which the wall portion is provided until it contacts the wall portion, so that the roller that contacts the wheel during use is separated from the wheel.

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