JP3592766B2 - Planetary roller reducer with direct motor connection - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a planetary roller speed reducer directly connected to a motor for assisting driving of a bicycle.
[0002]
[Prior art]
An example of the arrangement and function of a conventional transmission motor used as auxiliary power for a bicycle will be described with reference to FIGS. 5 to 8 (Japanese Patent Laid-Open No. 58-149277). A wheel 2 and a second freewheel 3 are mounted, and a first chain 5 is suspended between the first freewheel 2 and a first gear 4 which is a driving sprocket. A second chain 8 is suspended between the drive shaft 6 and a second gear 7 attached to an output shaft of the drive motor 6.
In the middle of the first chain 5, a torque detector 9 for detecting the magnitude of the tension applied to the first chain 5 and converting it into an electric quantity (for example, electric resistance or electric capacity) is provided. More specifically, as shown in FIGS. 7 and 8, a tension arm 11 is attached to a rotating shaft 10 of the torque detector 9, and free gears 12 and 12 'are pivotally mounted on both ends thereof. The chain 5 is mounted, and the tension arm 11 is provided with a spring 13 for biasing the power clockwise in the drawing of FIG. With this configuration, the tension applied to the first chain 5 caused by the stepping force transmitted by the occupant via the pedal 14, the crank 15, and the first gear 4 causes the rotation of the rotation shaft 10 to rotate. It can be detected as an angle.
When the pedal 14 is depressed strongly at the time of starting, accelerating, climbing, or the like, a large tension is applied to the first chain 5, and the tension arm 11 rotates counterclockwise in the drawing against the elastic pressure of the spring 13. Then, the slider (not shown) of the potentiometer 9 connected to the rotating shaft 10 is rotated by an angle corresponding to the tension. When the motor rotates more than the required angle, the electric power of the motor 6 is supplied, the second gear 7 attached to the output shaft of the motor 6 rotates to rotate the second freewheel 3 via the second chain 8, and The wheels will be driven, and the rear wheels will be driven by the combined torque of both human power and the motor.
To put it the other way around, applying the same drive torque to the rear wheels reduces the burden on humans as compared with conventional bicycles. On the other hand, when traveling on a flat road, light torque is sufficient, so that the tension applied to the first chain 5 is reduced, and the rotation angle of the tension arm 11 is also reduced, so that the power supply to the motor 6 is stopped and only the rotation of the pedal is performed. The bicycle will run with the power of.
[0003]
One general conventional example of the structure of the motor 6, which is the prime mover used for such auxiliary power, will be described. The structure shown in FIG. 9 is a small and compact example. That is, a thin planetary gear reducer is directly connected to the thin DC motor 21. Reference numeral 22 denotes an output shaft of the motor 21, and a sun gear 22 a is directly formed on the tip of the output shaft 22. An internal gear 23 attached to a reduction gear casing 28, a plurality of planetary gears 24 internally meshed with the internal gear 23, and externally meshed with the sun gear 22 a, and these planetary gears 24 are connected by respective planetary gear shafts 25. The planetary gear carrier 26a that supports the shaft constitutes a planetary gear reduction mechanism. The planetary gear carrier 26a is integrated with the output shaft 26, and a sprocket wheel 27 is mounted on the output shaft 26, and a chain for driving the rear wheel of the bicycle is hung.
[0004]
[Problems to be solved by the invention]
As described above, the reduction gear of the conventional auxiliary power motor is a gear system, so there is a backlash between the meshing gears, and when used as an auxiliary power for a bicycle, vibration and noise due to speed fluctuations occur when the motor power is energized. Worsened. Also, since the chain is wound around the output end of the power unit , not only does the width of the power unit protrude as compared with the width of the bicycle, but also the output shaft 26 is easily bent by the cantilever support, and it is difficult to balance left and right. there were.
Therefore, the present invention solves the above-mentioned conventional problems and provides a motor-coupled planetary roller speed reducer that is small in vibration and noise, and excellent in durability.
[0005]
[Means for Solving the Problems]
Therefore, the present invention provides a thin motor having a mounting flange on the outer periphery of a casing and a sun roller formed at the end of an output shaft, and an output shaft of the motor mounted on the flange of the motor and having an inner small-diameter cylindrical portion. A window for inserting an output chain is bored in the large-diameter cylindrical body on the outside supported by bearings, and the elastic ring or inner roller is fitted concentrically with the motor shaft on the inner circumference of the end face of the body. A plurality of planetary rollers that are circumscribed to the machine casing and the sun roller at the end of the motor output shaft, and are inscribed in the elastic ring or the inner roller; a planetary roller shaft rotatably supporting these planetary rollers; A planetary roller carrier comprising a planetary roller carrier rotatably supported via bearings on a small-diameter cylindrical portion inside the speed reducer casing and constituting an output of the speed reducer; A planetary roller carrier mounted on the planetary roller carrier, and a bearing for supporting the planetary roller carrier is disposed inside the output sprocket wheel disposed between the sun roller and the motor. Is designed to directly receive the tensile force of the chain applied to the output sprocket, and this is used as means for solving the problem.
The present invention also provides a bicycle having an auxiliary power mechanism, wherein the output sprocket of the motor-coupled planetary roller speed reducer is connected to a driven sprocket mounted on a rear wheel axle via a chain.
Further, the present invention provides a thin motor having a mounting flange portion on the outer periphery of a casing and a sun roller formed at the tip of an output shaft, and a small-diameter cylindrical portion mounted on the flange portion of the motor to support the output shaft of the motor. A pair of large windows are formed symmetrically in the radial direction on the large-diameter cylindrical body on the outer side of the support, and an elastic ring or an inner roller is fitted concentrically with the motor shaft on the inner periphery of the end face of the body. A plurality of planetary rollers circumscribing the sun roller at the tip of the motor output shaft and inscribing the elastic ring or the inner roller, the planetary roller shaft that rotatably supports these planetary rollers, and the roller shaft fixed together. A planetary roller carrier rotatably supported via a bearing on the small-diameter cylindrical portion inside the speed reducer casing to constitute the output of the speed reducer. And La deceleration mechanism, said is constituted by an output end attached to the planetary roller carrier is arranged a bearing for supporting the planetary roller carrier between the sun roller and the motor, and the output terminal and concentrically within said output end And this is used as a means for solving the problem.
[0006]
[Action]
By the above means, the rotation of the output shaft of the motor is reduced to the expected output rotation by the high reduction ratio planetary roller reduction mechanism directly connected thereto, and the required torque is output. Low vibration and noise due to rolling friction drive using planetary rollers.
Since the sun roller is formed at the output shaft end of the thin motor and the planetary roller reduction mechanism is formed on the rotation surface of the sun roller, the axial length of the entire combination of the motor and the reduction mechanism is reduced. In addition, a speed reduction mechanism output shaft formed as a planetary roller carrier is provided between the motor and the speed reduction mechanism, and an output chain hung on a sprocket wheel attached to the output shaft is connected to the speed reducer casing. Since the driven sprocket wheel is linked to the driven sprocket wheel through the side window, it is possible to move closer to the center line of the vehicle when installing the motored reducer on a narrow vehicle such as a bicycle. It is possible to avoid a large imbalance in weight.
Also, since the bearing supporting the planetary roller carrier is arranged so as to overlap the same position inside the output sprocket wheel, the bearing directly receives the tensile force of the chain applied to the output sprocket, and the cantilever as in the prior art is provided. Since it does not receive bending stress unlike the output shaft, it has excellent durability.
[0007]
【Example】
FIG. 1 is a side sectional view of a planetary roller speed reducer 30 directly connected to a motor, and FIG. 2 is a front view showing an AA section of FIG.
The structure of the motor-directed planetary roller reducer 30 will be described. Reference numeral 31 denotes a thin DC motor composed of a thin disk-shaped armature, permanent magnet stators, rectifying brushes, etc., wired by printed coils or the like. A sun roller 32a is formed at the tip of the output shaft 32 of the motor 31. The outer periphery of the motor 31 is provided with a mounting flange, on which a reduction gear casing 41 is mounted. A small-diameter cylindrical portion 41b provided inside the reduction gear casing 41 supports the motor output shaft 32 via a bearing 50, and a pair of large windows 41a is provided symmetrically at a radial position on the outer large-diameter cylindrical body. (FIG. 2) is provided, and a circumferential step portion for fitting the elastic ring 33 or the shrink-fit type inner roller 33a is provided on the inner circumference of the arrangement surface of the body portion. A sun roller 32a at the end of the motor output shaft 32, an elastic link 33 fastened and fixed by a speed reducer casing 41 and a speed reducer lid 42, a plurality of planetary rollers 34 pressed against this, and planetary rollers via bearings A planetary roller shaft 35 for rotatably supporting the roller 34 and a planetary roller carrier 36 for fixing and supporting the roller shaft 35 constitute a planetary roller reduction mechanism. The planetary roller carrier 36 is rotatably supported via a bearing 38 in a small-diameter cylindrical portion 41b inside the reduction gear casing 41, and serves as an output shaft of the reduction gear. An output sprocket wheel 37 is mounted on the planetary roller carrier 36. The reduction ratio 1 / n of this planetary roller reduction mechanism is
1 / n = sun roller diameter / (sun roller diameter ÷ elastic ring inner diameter)
The output torque of the output sprocket wheel 37 is n times the motor output torque if the mechanical loss of power transmission is ignored.
The operation of the motor-directed planetary roller reducer 30 will be described. When the rotation of the output shaft 32 of the motor is reduced to 1 / n by the planetary roller reduction mechanism directly connected to the output shaft 32, a large required torque is obtained, and vibration and noise are reduced.
The sun roller 32a is formed at the end of the output shaft 32 of the DC thin motor 31, and the planetary roller reduction mechanism is formed on the rotation surface of the sun roller 32a. Therefore, the axial length of the entire combination of the motor 31 and the reduction mechanism is reduced. It is compact. In addition, the output shaft of the planetary roller carrier 36, which is the output shaft of the reduction mechanism to which the output sprocket wheel 37 is attached, is provided between the motor 31 and the reduction mechanism, and the output chain 39 that is hung on the output sprocket wheel 37. Is connected to the driven sprocket wheel through the window 41a on the side of the speed reducer casing 41, so that it can approach the center line of the vehicle body when mounted on a narrow and lightweight vehicle such as a bicycle. For this reason, the device fits well and can avoid a large imbalance in weight.
Further, since a bearing 38 such as a ball bearing for supporting the planet carrier 36 is arranged concentrically inside the radial direction of the output sprocket wheel 37, the bearing 38 linearly reduces the tensile force of the chain 39 applied to the output sprocket 37. Since it can be subjected to a bending stress unlike a conventional cantilevered output shaft, durability is improved and there is no phenomenon such as center runout.
[0008]
Next, an example in which the motor-coupled planetary roller reducer 30 is attached to a bicycle will be described. FIG. 3 is a side view of the bicycle, and FIG. 4 is an enlarged view of a cross section taken along line BB of FIG.
Reference numeral 16 denotes a bicycle with auxiliary power, and reference numeral 4 denotes a sprocket wheel mounted on the crankshaft 15 which is manually operated. 14 is a pedal for rotating the crankshaft 15. Reference numeral 5 denotes a chain that connects the driven sprocket wheel 2 and the sprocket wheel 4 attached to the shaft of the rear wheel 17 of the bicycle 16 via a one-way clutch to transmit the torque of the crankshaft 15 rotated by human power. It is. The display of the part number of the bicycle up to this point is the same as that of the conventional bicycle power mechanism because it has the same structural function.
The rim for supporting the tire of the rear wheel 17 is illustrated as a molded product integral with the rear wheel hub and having a biased support disk portion. With such a structure, the motor-coupled planetary roller speed reducer 30 can be conveniently mounted between the components of the bicycle 16 as shown in the figure (a large number of spokes normally support the rim of the tire). In the case of, the motor-directed reduction gear 30 can be brought close to the extent that it does not touch the spokes, but it moves slightly lower than that shown in FIG. 4, and in this case, the output sprocket wheel 37 moves outward. Due to the displacement, the position of the driven sprocket wheel 45 also moves outward, the hub of the rear wheel becomes slightly longer, and the mounting width of the rear wheel shaft becomes slightly wider.)
An output sprocket wheel 37 of the speed reducer and a driven sprocket wheel 45 attached to the rear wheel axle of the bicycle via a one-way clutch are linked by a chain 39. A torque sensor 19 is provided on the tension side of the chain 5. The torque sensor 19 is such that the roller at the tip of the lever always pushes the chain 5 upward by a spring or the like, and when the chain 5 is pulled strongly, the roller is pushed and the lever rotates to detect the displacement, thereby obtaining torque during operation. When the driving bicycle 16 approaches a hill or the like and the driving torque by human power becomes a certain value or more, the torque sensor 19 detects the torque, and an electric control (not shown) is performed. By the function of the circuit, an electric current is sent from the mounted battery 46 to the motor-directed planetary roller speed reducer 30, which can be driven to assist human power. When the road becomes flat and the driving torque of the bicycle 16 can be reduced, the torque sensor 19 stops transmitting to the auxiliary drive, the motor-equipped reduction gear 30 stops, and the bicycle 16 runs manually. Since the driven sprocket wheels 2 and 45 are mounted via the rear wheel axle and the one-way clutch, there is a possibility that the driven sprocket wheels 2 and 45 may interfere with each other even during operation by human power, during operation by the reduction gear device 30 with the motor, or during movement of the bicycle by inertia. Not.
[0009]
【The invention's effect】
As described in detail above, the present invention uses a planetary roller speed reducer, and therefore has less vibration and noise than a gear type speed reducer. A sun roller is formed at the output shaft end of the thin motor, and a planetary roller reduction mechanism is formed on the rotation surface of the sun roller. Since the output shaft side is disposed in a space between the motor and the sun roller, the sun and the motor are decelerated. The axial length of the entire combination of mechanisms can be reduced. When using this planetary roller reducer with motor as auxiliary power for a bicycle, the output chain sprocket is placed between the thin motor and the thin reducer, so the reducer does not need to travel and the driven sprocket does not need to travel significantly. Eliminates and fits easily. Further, the speed reducer can be configured symmetrically around the chain. A bearing for supporting the planet carrier is disposed concentrically inside the output sprocket wheel, and the bearing directly receives the tensile force of the chain applied to the output sprocket and receives bending stress like a cantilever output shaft. Since there is no bearing, the load capacity of the bearing can be small, and the durability can be improved without the center runout.
[Brief description of the drawings]
FIG. 1 is a side sectional view of a planetary roller speed reducer directly connected to a motor according to an embodiment of the present invention.
FIG. 2 is a front view showing an AA cross section of FIG. 1;
FIG. 3 is a side view showing a bicycle to which the speed reducer of FIG. 1 is attached.
FIG. 4 is an enlarged plan view showing a BB cross section of FIG. 3;
FIG. 5 is a side view showing an outline of a conventional bicycle power mechanism.
FIG. 6 is a plan view of the power mechanism of the bicycle of FIG. 5;
FIG. 7 is a front view showing an example of a torque detector in FIG. 5;
FIG. 8 is a plan view of the torque detector shown in FIG. 7;
FIG. 9 is a side sectional view of a conventional motor-directed planetary gear reducer.
[Explanation of symbols]
Reference Signs List 16 Bicycle with auxiliary power 17 Rear wheel 19 Torque sensor 30 Planetary roller reducer directly connected to motor 31 Thin DC motor 32 Motor output shaft 32a Sun roller 33 Elastic ring or inner roller 34 Planetary roller 35 Planetary roller shaft 36 Planetary roller carrier 37 Output sprocket 38 Ball bearing (bearing)
39 chain 41 reduction gear casing 41a casing window 45 driven sprocket 50 bearing

Claims (3)

A thin motor having a mounting flange on the outer periphery of the casing and a sun roller formed at the end of the output shaft, and a small-diameter cylindrical portion mounted on the flange of the motor and supporting the output shaft of the motor via bearings with an inner small-diameter cylindrical portion. A window for inserting an output chain through a large-diameter cylindrical body portion, and a reduction gear casing in which an elastic ring or an inner roller is fitted concentrically with a motor shaft on an inner periphery of an end surface of the body portion; A plurality of planetary rollers that circumscribe the sun roller at the tip of the output shaft and inscribe the elastic ring or the inner roller, a planetary roller shaft that rotatably supports these planetary rollers, and an inside of the reduction gear casing that fixes and supports the roller shaft. A planetary roller reduction mechanism comprising a planetary roller carrier rotatably supported via a bearing on a small diameter cylindrical portion of the above to constitute an output of the reduction gear; And a bearing for supporting the planetary roller carrier is disposed inside the output sprocket wheel disposed between the sun roller and the motor, and the bearing engages the output sprocket. A planetary roller reducer directly connected to a motor that directly receives the tensile force of chain. A bicycle equipped with an auxiliary power mechanism, wherein the output sprocket of the motor-directed planetary roller speed reducer according to claim 1 is connected to a driven sprocket mounted on a rear wheel shaft via a chain. A thin motor having a mounting flange on the outer periphery of the casing and a sun roller formed at the tip of the output shaft, and an output shaft of the motor mounted on the flange of the motor and supported by a small-diameter inner cylindrical portion via a bearing. A large-diameter cylindrical body is provided with a pair of large windows symmetrically in the radial direction, and a reduction gear casing in which an elastic ring or an inner roller is fitted concentrically with the motor shaft on the inner periphery of the end face of the body. A plurality of planetary rollers circumscribing the sun roller at the end of the motor output shaft, and being inscribed in the elastic ring or the inner roller, a planetary roller shaft rotatably supporting these planetary rollers, and the roller shaft fixedly supported and fixed to the roller shaft A planetary roller reduction mechanism comprising a planetary roller carrier rotatably supported via a bearing on a small-diameter cylindrical portion inside the machine casing and constituting an output of the speed reducer, Serial is constituted by an output end attached to the planetary roller carrier is arranged a bearing for supporting the planetary roller carrier between the sun roller and the motor, and formed by arranging said output end and concentrically within said output end Planetary roller reducer directly connected to the motor.

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