JP4138374B2 - Wheel drive device and golf car - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drive device for driving a wheel mounted on an axle, and more particularly to a wheel drive device capable of transmitting a driving force with a large reduction ratio through a short transmission path and a golf car using the same. .
[0002]
[Prior art]
Conventionally, in a wheel drive device, a path through which a rotational force from a drive source to a wheel is transmitted is configured to have as high a transmission efficiency as possible. In particular, in a small electric vehicle such as a golf car, in order to reduce the size and weight, there is a demand for a drive device that has a transmission path from a drive source to an axle as short as possible and has high transmission efficiency.
[0003]
5 to 7 show a conventional golf car and its driving device.
[0004]
In the driving device 31 of the golf car 30, a battery 35 and a driving motor 36 are disposed below the rear seat 32 and on the front side of the axle 34 of the rear wheel 33. As shown in FIGS. The transmission path is configured so that the driving force is transmitted from the output shaft 37 of 36 to the axle 34 of the rear wheel 33 via the speed reduction mechanism 38 and the differential device 39.
[0005]
The speed reduction mechanism 38 includes four gears 41a, 41b, 41c, and 41d as power transmission components. Here, by using the four gears 41a to 41d, a predetermined large reduction ratio is obtained without using an excessively large gear.
[0006]
The differential device 39 is disposed substantially in the middle between the left and right rear wheels 33, and the final gear 41 d of the speed reduction mechanism 38 forms a part of the differential case 40. The rotation from the gear 41d is transmitted to the left and right axles 34 via the pinion 42.
[0007]
The drive device 31 is provided with an electromagnetic brake 43 as a parking brake. The electromagnetic brake 43 is disposed on the output shaft 37 side of the drive motor 36 so as to obtain a large braking force according to the reduction ratio. Further, as shown in FIG. 6, a vehicle speed sensor 45 is mounted on the differential device 39 side of the housing 44, and the electromagnetic brake 43 is operated by detecting the rotation stop of the gear 41 d, so that the output shaft 37 It is comprised so that the stop state of rotation may be maintained.
[0008]
In the golf car 30 having such a drive device, the rotational force of the drive motor 36 is transmitted to the axle 34 via the speed reduction mechanism 38 and the differential device 39, whereby the rear wheel 33 is driven and travels. Further, when the vehicle stops, the rotation of the output shaft 37 of the drive motor 36 is stopped by the electromagnetic brake 43.
[0009]
[Problems to be solved by the invention]
However, in such a drive device 31, the rotational force of the drive motor 36 is transmitted via a large number of gears 41 a to 41 d, so that the number of power transmission components and accompanying components is large, and the weight of the drive device 31 is increased. It tends to be heavy. Further, since backlash exists between each of the gears 41a and 41b and between each of the gears 41c and 41d, the backlash between each gear tends to be combined and easily increased. As a result, due to the backlash, noise during driving of the drive device 31 tends to increase, and the rear wheel 33 rotates immediately after the rotation of the drive motor 36 stops, so that the vehicle body is shaken and smooth. It had problems such as it was difficult to stop.
[0010]
Further, in such a drive device 31, the output shaft 37 of the drive motor 36 and the axle 34 are arranged close to each other in parallel, so that the differential device 39 disposed at the center between the pair of left and right rear wheels 33. On the other hand, the drive motor 36 is disposed at a position shifted to the right or left, so that there is a problem that the weight balance of the vehicle body is poor and traveling stability is likely to be lowered.
[0011]
Therefore, the present invention provides a wheel driving device that can easily reduce the size and weight, suppress backlash, and obtain sufficient transmission efficiency, and a golf car equipped with such a wheel driving device. This is the issue.
[0012]
Another object is to improve the weight balance of the vehicle body.
[0013]
[Means for Solving the Problems]
In order to solve the above-described problem, a wheel drive device according to claim 1 is engaged with a drive source that outputs a rotational force, a worm that is rotationally driven by the drive source, and a thread-like tooth of the worm. A driven wheel and an axle of a pair of left and right drive wheels connected to the wheel via a differential device, the wheel constituting a part of a differential case of the differential device, and a wheel body rotary shaft along the radial direction a plurality provided at predetermined intervals on the outer periphery of the wheel body, the rotating body to the rotational axis rotatably mounted respectively, of the worm between the rotating bodies adjacent the wheel The screw-shaped teeth are meshed, and when the worm rotates, the rotating body rolls to rotate the wheel.
[0014]
A wheel drive device according to a second aspect is characterized in that, in addition to the configuration according to the first aspect, the drive source is a drive motor.
[0015]
Furthermore, in the wheel drive device according to claim 3, in addition to the configuration according to claim 2, the drive wheel is a pair of left and right rear wheels, and the wheel is disposed substantially in the middle of the pair of left and right rear wheels. The wheel shaft and the axle are provided on the same shaft, the output shaft of the drive motor and the worm shaft are provided on the same shaft, and the drive motor is provided on the front side of the axle of the rear wheel. It is arranged.
[0016]
According to a fourth aspect of the present invention, in addition to the configuration of the second or third aspect, the drive motor is arranged on the upper side of the worm so that the output shaft of the drive motor is in a direction along the vertical direction. It is characterized by being arranged in.
[0017]
Furthermore, the wheel drive device according to claim 5 is provided with an electromagnetic brake directly connected to the output shaft at an upper portion of the drive motor, in addition to the configuration according to claim 4, and the output shaft of the drive motor. A vehicle speed sensor capable of detecting rotation is provided, and the electromagnetic brake is operated by detecting a stop state of the output shaft by the vehicle speed sensor.
[0018]
According to a sixth aspect of the present invention, in addition to the configuration according to any one of the first to fifth aspects, the plurality of rotating bodies are detachably mounted on the wheel body. It is characterized by that.
[0019]
A golf car according to a seventh aspect is characterized in that the pair of left and right wheels are driven by the driving device according to any one of the first to sixth aspects.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
[0021]
FIGS. 1 and 2 show the drive device of this embodiment, and FIGS. 3 and 4 show a golf car equipped with the drive device.
[0022]
In the figure, reference numeral 10 denotes a driving device for driving a rear wheel 33 of the golf car 30. As shown in FIGS. 1 and 2, the drive device 10 includes a drive motor 11 as a drive source, and a speed reduction mechanism 13 and a differential device 14 are sequentially connected to an output shaft 12 of the drive motor 11. The transmission shaft is configured such that the axle 34 of the left and right rear wheels 33 is connected to the moving device 14 and the rotational force of the output shaft 12 of the drive motor 11 is transmitted to the axle 34. Here, the drive motor 11 is disposed on the front side with respect to the axle 34 and on the upper side of the speed reduction mechanism 13 so that the output shaft 12 is along the vertical direction. The speed reduction mechanism 13 and the differential device 14 are the drive motor. 11 is integrally provided in a housing 16 attached to the housing 11.
[0023]
The speed reduction mechanism 13 includes a worm 18 that is directly connected to the lower output shaft 12 of the drive motor 11 and is driven to rotate, and a wheel 20 that meshes with the worm 18 and is driven. On the outer peripheral surface of the worm 18, screw-like teeth 19 are formed at a predetermined pitch. On the other hand, the wheel 20 includes a rotatable substantially circular wheel main body 21 and a plurality of rotating bodies 22 disposed on the outer periphery of the wheel main body 21 and meshable with the screw-shaped teeth 19. The plurality of rotating bodies 22 have a cylindrical shape, and are rotatably attached to rotating shafts 23 along the radial direction of the wheel body 21. The rotating bodies 22 are arranged in a state of protruding from the outer periphery of the wheel body 21 and are arranged at a predetermined interval corresponding to the pitch of the screw-like teeth 19.
[0024]
The wheel 20 and the worm 18 are combined with each other, and the screw-like teeth 19 of the worm 18 are engaged between the adjacent rotators 22, and the outer peripheral surface of the rotator 22 is engaged with the groove side surface portion of the screw-like teeth 19. When the worm 18 is rotated in a state where it is in contact, the rotating body 22 is pressed by the screw-like teeth 19 while rolling, whereby the wheel 20 is rotated.
[0025]
In this speed reduction mechanism 13, the reduction ratio can be set with respect to the worm 18 by the number of rotating bodies 22 of the wheel 20. Here, by increasing the number of rotating bodies 22, a large number of conventional gears 41a to 41d. It is set to a predetermined large reduction ratio equivalent to the speed reduction mechanism using the.
[0026]
The differential device 14 is configured to transmit the rotational force transmitted from the speed reduction mechanism 13 to the differential case 24 to the side gear 26 provided at the end of the axle 34 via the pinion 25. In this differential device 14, since a part of the differential case 24 is constituted by the wheel 20, the rotational force decelerated by the speed reduction mechanism 13 is directly transmitted from the wheel 20 to the differential device 14.
[0027]
An electromagnetic brake 27 is directly connected to the output shaft 12 at the upper portion of the drive motor 11, that is, at the end 12 a opposite to the worm 18. The electromagnetic brake 27 is configured to maintain the output shaft 12 in a stopped state during operation. Further, a vehicle speed sensor 28 capable of detecting the rotation of the output shaft 12 is provided at the end 12a of the output shaft 12, and the electromagnetic brake 27 is activated by detecting the stop state of the output shaft 12. Has been.
[0028]
In the golf car 30 of this embodiment, as shown in FIGS. 3 and 4, the driving device 10 as described above is mounted so as to drive the pair of left and right rear wheels 33. Here, the differential device 14 is disposed at the center between the left and right rear wheels 33, and the wheel 20 is disposed near the center thereof. A battery 35 is disposed on the front side of the drive motor 11.
[0029]
According to the wheel drive device 10 as described above, the rotational force of the drive motor 11 is constituted by the worm 18 that is rotationally driven by the drive motor 11 and the wheel 20 that is engaged with the screw-like teeth 19 of the worm 18 and driven. Is transmitted to the axle 34, so that a large reduction ratio can be obtained only by the worm 18 and the wheel 20, and the transmission path can be shortened to reduce the number of power transmission components.
[0030]
In particular, since the worm 18 is directly connected to the output shaft of the drive motor 11 and the wheel 20 forms a part of the differential case 24 of the differential device 14, a particularly short transmission path can be obtained. Therefore, the number of parts of the speed reduction mechanism 13 is small and it is easy to reduce the weight and size. And since the golf car 30 equipped with such a drive device 10 is light in weight, it is difficult to damage the turf even if it is on the turf during traveling.
[0031]
Further, since the speed reduction mechanism 13 is composed of the worm 18 and the wheel 20, there are few power transmission parts and there is no backlash caused by using a plurality of gears 41a to 41d as in the prior art. For this reason, noise is low when driving compared to a conventional speed reduction mechanism using a plurality of gears. Further, it is possible to suppress the rear wheel 33 from rotating when the output shaft 12 of the drive motor 11 stops rotating, and it is possible to perform a smooth stop with little shaking of the vehicle body immediately after stopping by operating the electromagnetic brake 27. It is.
[0032]
Moreover, since the screw-like teeth 19 of the worm 18 are meshed between the adjacent rotating bodies 22 and the worm 18 rotates, the rotating body 22 rolls and rotates the wheel 20. The resistance when the rotational force is transmitted from the worm 18 to the wheel 20 can be reduced, and the transmission efficiency is good. That is, in the case of a power transmission component in which the contact surfaces slide like the conventional worm gear, the resistance at the time of rotation transmission is large because it slides against the contact, but the rotation is transmitted when the rotating body 22 rolls. By doing so, there are few sliding parts, the resistance at the time of rotation transmission can be made small, and thereby sufficient transmission efficiency can be obtained.
[0033]
Further, although the drive motor 11 is driven by the battery 35, since the drive device 10 is small and light and has good transmission efficiency, energy consumption during driving can be reduced, and the cruising distance without increasing the capacity of the battery 35. Can be extended or the battery 35 can be made smaller.
[0034]
Further, the wheel 20 is disposed substantially in the middle of the pair of left and right rear wheels 33, the axis of the wheel 20 is on the same axis as the axle 34, and the shaft of the worm 18 that meshes with the wheel 20 and the drive motor 11. Since the output shaft 12 is on the same axis, the drive motor 11 having a large weight ratio in the vehicle body can be disposed substantially in the middle between the rear wheels 33, and the drive motor 11 is disposed on the front side of the rear wheel 33. Therefore, it can be disposed between the rear wheel 33 and the front wheel, and it is easy to improve the weight balance in the left-right direction and the front-rear direction of the vehicle body, and the running stability of the vehicle body can be improved.
[0035]
In addition, since the drive motor 11 is arranged on the upper portion of the worm 18 so that the output shaft 12 is in the direction along the vertical direction, the drive motor 11 can be mounted in an upright state, and the vehicle body can be arranged in the plane direction. It is possible to make the space compact.
[0036]
Furthermore, an electromagnetic brake 27 is provided directly on the output shaft 12 at the top of the drive motor 11, and a vehicle speed sensor 28 for detecting the rotation of the output shaft 12 of the drive motor 11 is provided. The vehicle speed sensor 28 outputs the output of the drive motor 11. Since the electromagnetic brake 27 is operated by detecting the stop state of the shaft 12, a large braking force according to the reduction ratio can be secured by the electromagnetic brake 27, and the electromagnetic brake 27 is provided below the driving device 10. Since it is not provided, it is easy to ensure the minimum ground clearance of the vehicle body.
[0037]
In addition, since the plurality of rotating bodies 22 are detachably attached to the wheel body 20, when some of the rotating bodies 22 are damaged, only the rotating bodies 22 can be replaced. Therefore, it is not necessary to replace the entire gear, and maintenance can be improved.
[0038]
The present invention is not limited to this embodiment, and can be changed as appropriate. For example, in the above description, the driving device 10 is configured to drive the rear wheel 33, but the front wheel may be driven.
[0040]
Furthermore, although the example of the golf car has been described above, the present invention can be applied to an electric vehicle other than the golf car, and can also be applied as a vehicle drive device using another drive source such as an engine. Is possible.
[0041]
【The invention's effect】
As described above in detail, according to the wheel drive device of the first aspect, the rotation of the drive source is performed by the worm that is rotationally driven by the drive source and the wheel that is meshed with the thread-like teeth of the worm and is driven. Since the force is transmitted to the axle, a large reduction gear ratio can be achieved with a small number of power transmission components, and the number of components can be reduced to reduce weight and size. In addition, since the rotational force is transmitted with a small number of power transmission components, it is possible to prevent the occurrence of a large combined backlash as in the prior art. As a result, noise during driving can be suppressed, and rotation of the driving wheel can be suppressed when rotation of the output shaft of the driving source is stopped, and the vehicle can be stopped smoothly by suppressing shaking of the vehicle body immediately after stopping. Is possible.
[0042]
In addition, the rotating body has a plurality of rotating bodies arranged at predetermined intervals on the outer periphery of the wheel body, and the rotating bodies are rotatably attached to the rotating shafts along the radial direction of the wheel body, and adjacent rotating bodies. When the worm's screw teeth are meshed between the two and the worm rotates, the rotator rolls to rotate the wheel, so the rotator rolls and rotates from the drive source. Force can be transmitted, resistance is small compared to a power transmission component in which the contact surfaces of the gear teeth slide and rotate, and sufficient transmission efficiency as a wheel drive device can be obtained. In addition, since the wheel constitutes a part of the differential case of the differential device, the transmission path from the worm to the differential apparatus is shortened, and the number of parts of the transmission path is reduced, thereby reducing weight and size. It becomes possible.
[0043]
Further, according to the wheels of the driving device according to claim 2, when the driving source is a driving motor, since energy consumption is small, can be or or extending the driving range, the battery smaller, particularly effective It is remarkable.
[0044]
According to the wheel drive device of the third aspect, the drive wheel is a pair of left and right rear wheels, the wheel is disposed substantially in the middle of the pair of left and right rear wheels, and the wheel shaft and the axle are the same. Since the output shaft of the drive motor and the worm shaft are provided on the same shaft, and the drive motor is arranged on the front side of the rear wheel axle, in addition to the above effects, the weight ratio in the vehicle body A large drive motor can be arranged between the rear wheel and the front wheel, approximately in the middle between the rear wheels corresponding to the wheels, so that it is easy to improve the weight balance in the left-right direction and the front-rear direction of the vehicle body. It is possible to improve the running stability.
[0045]
Further, according to the wheel drive device of the fourth aspect, since the drive motor is arranged on the upper part of the worm so that the output shaft is in the direction along the vertical direction, the vehicle is mounted on the vehicle with the drive motor standing. It is possible to make the arrangement space in the plane direction of the vehicle body compact.
[0046]
Further, according to the wheel drive device of the fifth aspect, the electromagnetic brake is provided directly on the output shaft of the drive motor, and the vehicle speed sensor for detecting the rotation of the output shaft of the drive motor is provided. Since the sensor detects the stop state of the output shaft and operates the electromagnetic brake, the electromagnetic brake can provide a large braking force according to the reduction ratio, and the backlash is small, enabling a smooth stop. In addition, since the electromagnetic brake is not provided on the lower side of the driving device, it is easy to secure the minimum ground clearance of the vehicle body.
[0047]
Further, according to the wheel drive device of the sixth aspect, since the plurality of rotating bodies are detachably attached to the wheel body, respectively, when some of the rotating bodies are damaged, only the rotating bodies are individually Therefore, it is not necessary to replace the entire power transmission component as in the prior art, and the maintainability can be improved.
[0048]
According to the golf car of the seventh aspect, the left and right rear wheels are driven by the driving device according to any one of the first to sixth aspects. Can reduce the noise of the golf car used in the car, and it is hard to damage the turf even if it gets on the turf.
[Brief description of the drawings]
FIG. 1 is a side view showing a cross section of a part of a drive device according to an embodiment of the present invention.
2 is a cross-sectional view taken along the line AA of FIG. 1 showing the drive device according to the embodiment; FIG.
FIG. 3 is a layout view of a golf car equipped with the driving device of the embodiment.
FIG. 4 is a layout view of a golf car equipped with the driving device of the embodiment.
FIG. 5 is a side view of a conventional golf car.
FIG. 6 is a side view showing a part of a conventional driving device in section.
7 is a cross-sectional view taken along the line BB of FIG. 6 showing a conventional driving device.
[Explanation of symbols]
10 drive device 11 drive motor (drive source)
12 Output shaft 13 Deceleration mechanism 14 Differential device 18 Worm 20 Wheel 21 Wheel body 22 Rotating body 23 Rotating shaft 27 Electromagnetic brake 28 Speed sensor 30 Golf car 33 Rear wheel 34 Axle 35 Battery

Claims (7)

A drive source that outputs rotational force, a worm that is rotationally driven by the drive source, a wheel that meshes with and follows the screw-like teeth of the worm, and a pair of left and right connected to the wheel via a differential device And driving wheel axles,
The wheel is configured to form a part of a differential case of the differential device, the rotation shaft along a radial direction of the wheel body is provided with a plurality at predetermined intervals on the outer periphery of the wheel body, the rotating body to the rotational axis Each can be pivoted,
The screw-like teeth of the worm are meshed between the rotating bodies adjacent to the wheel, and when the worm rotates, the rotating body rolls to rotate the wheel. Wheel drive device.   The wheel drive device according to claim 1, wherein the drive source is a drive motor.   The drive wheel is a pair of left and right rear wheels, the wheel is disposed substantially in the middle of the pair of left and right rear wheels, the wheel shaft and the axle are provided on the same axis, and the output shaft of the drive motor The wheel drive device according to claim 2, wherein the worm shaft and the worm shaft are provided on the same axis, and the drive motor is disposed on the front side of the axle of the rear wheel.   The wheel drive device according to claim 2 or 3, wherein the drive motor is arranged above the worm so that an output shaft of the drive motor is in a direction along a vertical direction. An electromagnetic brake is provided directly on the output shaft on the drive motor, and a vehicle speed sensor capable of detecting rotation of the output shaft of the drive motor is provided.
5. The wheel driving device according to claim 4, wherein the electromagnetic brake is operated by detecting a stop state of the output shaft by the vehicle speed sensor.   The wheel driving device according to any one of claims 1 to 5, wherein each of the plurality of rotating bodies is detachably attached to the wheel body.   A golf car comprising a pair of left and right wheels driven by the driving device according to any one of claims 1 to 6.

Images