TWI786567B - Electric bicycle booster of outer-rotor-type wheel hub motor using one-stage involute planetary gear reduction mechanism with small teeth number differences - Google Patents

Abstract

An electric bicycle booster device with a first-order involute small-tooth-difference planetary gear reduction transmission mechanism with an outer rotor hub motor has the highest reduction ratio among all first-order planetary gear reduction transmission mechanisms at one tooth difference, wherein the inner stator, The ring gear bracket is fixed on the fixed shaft in the center of the hub, and the hub shaft with the eccentric shaft is locked in the groove of the outer rotor by screws, and rotates with the outer rotor as the input rotating part. The input rotating part is located on the outer rotor The two ball bearings on both sides of the rotor and the fixed shaft in the center of the hub are used as support, and drive the planetary gear with only one tooth difference with the ring gear to perform planetary motion around the ring gear fixed on the ring gear bracket, and the planetary gear is driven by the hole pin The joint mode drives the output intermediary, and then the output intermediary, which is interference-fitted in the housing, drives the hub shell for output rotation.

Description

Electric bicycle booster device with first-order involute planetary gear reduction transmission mechanism and external rotor hub motor

The invention relates to a first-order involute less-tooth-difference planetary gear reduction transmission mechanism of an outer rotor hub motor booster device for an electric bicycle, especially an electric bicycle outer rotor that can realize miniaturization, high mechanical efficiency and boosting boosting effect The technology of the hub motor power-assisted transmission mechanism.

Due to the continuous relationship of the new crown pneumonia epidemic, people in Europe and the United States are afraid of taking crowded and closed subways or buses. Bicycles that are environmentally friendly and can maintain social distance have become popular means of transportation. From London, Paris, Berlin, Milan, and the United States Major cities such as Philadelphia, Denver, Bogota in Colombia, and Sydney and Melbourne in Australia have expanded bicycle lanes and subsidized the purchase of bicycles to encourage citizens to use bicycles as a means of transportation. The production capacity of major bicycle factories is in short supply. And when the commute or leisure destination is far away or the rider has an uphill section on the road, the electric bicycle with the motor assist device is more in line with the demand. Therefore, the electric bicycle market has been growing in recent years, and sales booms have been maintained in European countries. Therefore, electric bicycles are an important key direction for Taiwan's bicycle industry to continue to lead and make profits in the world's bicycle industry.

At present, the common electric bicycle assisting device on the market is to use Brush hub motors are divided into brushless hub motors without gears and brushless hub motors with gears according to whether the motor passes through a gear reduction mechanism. Figure 1 is the actual diagram of the gear reduction mechanism in a brushless hub motor with gears commonly used in the market, including a central gear 51, three middle idler gears 52 and its wheel disc 53 (fixed part), and a ring gear with internal teeth 54. The gear reducers with brushless gear hub motors on the market all use centering gear trains. Although the number of teeth of the ring teeth 54 is as many as 93, the reduction ratio is not high. For example, the number of teeth of the central gear 51 is 21, and the reduction ratio is only -4.4 (the minus sign means that the direction of output and input is reversed). The new patent No. M484555 "bicycle power-assisted motor with one-way function" adopts a compound gear train, and the large-diameter gear and the small-diameter gear pinned to the same shaft mesh with the central gear and the ring gear respectively. The reduction ratio can be higher than that of the centering gear system through gear matching (for example, the central gear with 20 teeth drives the large-diameter tooth part with 60 teeth, and the small-diameter tooth part with 20 teeth that rotates with the large-diameter tooth part drives the ring gear with 93 teeth). (approximately -14), but also requires a large tooth input fit. Therefore, the gear reduction mechanism of hub motors on the market has poor deceleration and torque boosting effects, which makes climbing long and steep slopes weak.

The sun gear in the ordinary planetary gear reducer is removed and when the difference between the number of teeth of the fixed ring gear and the planetary gear is very small, it is called a planetary gear reducer with small tooth difference. The planetary gear reducer with small tooth difference has a higher reduction ratio than the reduction mechanism with a centering wheel (including simple and compound gear trains), so it can improve the output torque effect of the hub motor, and the number of teeth can be smaller, that is Small size and weight. At present, the first-order small tooth difference planetary gear reducer can be divided into involute small tooth difference reducer, cycloidal pin wheel reducer and harmonic reducer. However, the cycloid reducer requires a very precise center distance and a very precise tooth shape, otherwise the output speed and torque are quite easy to fluctuate. invention Patent No. I694952 "Harmonic Gear Transmission Mechanism for Electric Bicycle Power Booster" is to apply the harmonic reducer to the power-assisted device of the electric bicycle, but the harmonic reducer has a flexible spline, so the rigidity and strength are poor, and the lifespan tends to be low, and the manufacturing cost is also quite high. As for the involute less-tooth-difference reducer, it does not have the disadvantages of the above two reducers, but the design of the tooth profile of the gear set is difficult, and it is easy to interfere with the tooth profile. Therefore, shift gears and non-standard modules must be used. Design technology can overcome the difficulty of tooth profile design.

Another common type is the RV reducer. Since the first stage uses a sun gear to drive the planetary gear, and the second stage uses a cycloidal pin gear reduction mechanism with a small tooth difference, the structure is complex, the volume is relatively large, and the weight is relatively heavy. It is not suitable as a power assist device for electric bicycles.

The present invention is mainly aimed at the lack of the gear reduction mechanism of the outer rotor hub motor of the current electric bicycle and the application of the known gear reducer to the electric bicycle booster, and is a brand new invention.

，其中z _i 代表齒輪i的齒數。如前所述，單式與複式齒輪系其93齒的圈齒的減速比才-4.4與-14(尚需大徑齒部60齒)，使用一階漸開線少齒差行星齒輪減速機構能以較少的齒數即可達成較高的減速比，如行星齒輪11、齒圈12的齒數各為20與21時減速比可達成-20；各為30與31時減速比可達成-30；各為40與41時減速比可達成-40。顯而易見，使用一階漸開線少齒差行星齒輪減速機構於電動自行車的外轉子式輪轂電機之動力傳動機構上，可以實現小型化、輕量化與提升助力的效果。此外一階相較二階行星齒輪減速機構其機械效率可以達到更高。 The main purpose of the present invention is to provide a first-order involute less-tooth-difference planetary gear reduction mechanism for a booster device of an electric bicycle, mainly applying the first-order involute less-tooth-difference planetary gear reduction mechanism to the outer rotor type of an electric bicycle On the hub motor, in order to achieve miniaturization, high mechanical efficiency and enhance the effect of power assist. Fig. 2 is a schematic diagram of the first-order involute small tooth difference planetary gear reduction mechanism used in the present invention, wherein the hub rotating shaft 23 includes an eccentric rotating shaft 25, and the two are joined into one or integrally formed, and the teeth of the ring-shaped internal gear are provided. The ring 12 is a fixed part, and the eccentric shaft 25 of the hub shaft 23 drives the planetary gear 11 to perform planetary motion around the fixed ring gear 12, and drives the output intermediary part 14 (or output shaft) and the input of the hub shaft 23 by means of hole pin engagement. Shafts rotate on the same axis. This hole-pin joint method is that there are four or six pin holes 13 on the planetary gear 11, and there are also four or six pins 15 and self-lubricating bushings 16 on the corresponding output intermediary member 14, but must meet r _h =r _b +e, where r _h is the radius of the pin hole 13, r _b is the radius of the outer circle of the self-lubricating bush 16, and e is the eccentricity of the eccentric shaft. In this way, the hole-pin engagement is equivalent to a parallelogram mechanism, so the rotation speed of the planetary gear 11 is transmitted to the output intermediate member 14 through the hole-pin engagement to perform a constant-velocity center-to-center rotation. Figure 3 is an exploded schematic diagram of a first-order involute planetary gear reduction mechanism with small tooth difference (the axial positioning buckle between the eccentric shaft and the planetary gear is not shown), and the reduction ratio formula is:

, where z _i represents the number of teeth of gear i . As mentioned above, the reduction ratio of the 93-tooth ring teeth of the single and compound gear trains is only -4.4 and -14 (60 teeth are still required for the large-diameter teeth), and the first-order involute planetary gear reduction mechanism with small tooth difference is used. A higher reduction ratio can be achieved with a smaller number of teeth. For example, when the number of teeth of the planetary gear 11 and the ring gear 12 are 20 and 21, the reduction ratio can reach -20; when the number of teeth is 30 and 31, the reduction ratio can reach -30. ; When each is 40 and 41, the reduction ratio can reach -40. Obviously, using the first-order involute planetary gear reduction mechanism with small tooth difference on the power transmission mechanism of the outer rotor hub motor of the electric bicycle can achieve the effects of miniaturization, weight reduction and boosting power. In addition, the mechanical efficiency of the first-stage planetary gear reduction mechanism can be higher than that of the second-stage planetary gear reduction mechanism.

The technical means to achieve the purpose of the present invention includes three sub-assemblies of the first-order involute planetary gear reduction mechanism with small tooth difference, the hub motor including the inner stator, the outer rotor and the rotating shaft, and the hub shell. The first two sub-assemblies It is installed inside the hub shell, and these three subassemblies are assembled into a utility model with the effect of the present invention by means of supporting and connecting members including the central fixed shaft of the hub. The electric bicycle booster device with a first-order involute small tooth difference planetary gear reduction transmission mechanism and an outer rotor hub motor, the movement sequence of its deceleration and force increase is that the eccentric shaft of the hub shaft locked on the outer rotor of the hub motor drives the planetary gear The planetary motion is performed around the ring gear fixed on the ring gear bracket, and the planetary gear transmits its rotational speed to the output intermediary with the same rotation axis as the outer rotor at a constant speed through the constant velocity mechanism joined by the hole pin, and then fits in the housing by interference The output intermediary part drives the hub shell to rotate, because the hub shell is connected to the wheel frame through the spokes, and finally the hub shell drives the rim to output and rotate. The central fixed axis of the hub supports and fixes the inner stator through interference fit, flat key, shaft step and C-shaped retaining ring, and supports the rotating outer rotor and hub shaft through two bearings, and also supports the rotating hub shell through two bearings . There is a certain gap between the hollow hub rotating shaft and the fixed shaft at the center of the hub. The ring gear bracket is fixed to the fixed shaft in the center of the hub through interference fit, flat key, and two C-shaped buckles, and the ring gear is fixed to the ring gear bracket by screws.

11: Planetary gear

12: ring gear

13: pin hole

14: Output middleware

15:pin

16: Self-lubricating bushing

17: screw

21: Outer rotor

22: Inner stator

23: hub shaft

24: screw

25: Eccentric shaft

26: The second right ball bearing

27: The second left ball bearing

28: Outer rotor groove

31: shell body

32: Shell right side cover

33: Shell left cover

34: screw

35: The right ball bearing

36: left one ball bearing

37:Right seal

38:Left seal

41: hub center fixed axis

411: fixed axis ladder

42: ring gear bracket

43:Left flat key

44: C-shaped buckle on the left

45: Left two C-shaped buckle

46: Right side flat key

47:C-shaped buckle on the right side

51: Central gear

52: idler

53: Roulette

54: ring gear

Figure 1 is the actual diagram of the gear reduction mechanism in the brushless geared hub motor.

Fig. 2 is a schematic diagram of a first-order involute planetary gear reduction mechanism with few tooth differences of the present invention.

Fig. 3 is an exploded schematic view of the first-order involute planetary gear reduction mechanism with small tooth difference of the present invention, wherein the axially positioned retaining ring between the eccentric shaft and the planetary gear is not shown.

Fig. 4 is a perspective view of an electric bicycle booster according to an embodiment of the present invention.

Fig. 5 is an exploded view of an electric bicycle booster device according to an embodiment of the present invention, wherein the shell body and conventional accessories such as bearings, screws, and seals are not shown.

Fig. 6 is a sectional view of an electric bicycle booster according to an embodiment of the present invention.

In order for the benefit review committee to further understand the technical features and means of the present invention, it will be described in detail with specific embodiments and diagrams as follows: please refer to Figure 4 to Figure 6 at the same time, Figure 4 is the electric bicycle power-assisted device according to the embodiment of the present invention Figure 5 is an exploded view of an electric bicycle booster device according to an embodiment of the present invention, wherein the shell main body and conventional accessories such as ball bearings 26, 27, 35, 36, screws 17, 24, 34, and seals 37, 38 are not Drawing; Figure 6 is a cross-sectional view of an electric bicycle booster device according to an embodiment of the present invention. In the embodiment of the present invention, the electric bicycle booster device includes three sub-assemblies: a first-order involute planetary gear reduction mechanism with small tooth difference, an outer rotor hub motor, and a hub shell. The first two sub-assemblies are installed inside the hub shell. , and these three sub-assemblies are assembled into an electric bicycle booster with a first-order involute small-tooth-difference planetary gear reduction transmission mechanism with the effect of the present invention by means of supporting and connecting members.

The supporting and connecting components include hub center fixed shaft 41 and ring gear bracket 42 . A part of hub central fixed shaft 41 is installed in the inside of the hub shell, and a part is outside the hub shell and can be locked on the front fork or rear fork (not drawn) of the vehicle frame by nuts (not shown). out). In addition to the interference fit between the ring gear bracket 42 and the hub central fixed shaft 41, the left side flat key 43 is used for circumferential positioning and the left one C-shaped buckle 44 and the left two C-shaped buckle 45 are used for axial positioning.

The hub shell includes a shell main body 31 , a right shell cover 32 and a left shell cover 33 , and the three are connected by screws 34 . In practical application, the hub shell can be connected to the wheel frame (not shown) through the spokes (not shown), and the wheel hub shell drives the rim to rotate.

The outer rotor hub motor includes an outer rotor 21 , an inner stator 22 installed inside the outer rotor and a hub shaft 23 . In addition to the interference fit between the inner stator 22 and the central fixed shaft 41 of the hub, the right side flat key 46 is used for circumferential positioning and the fixed shaft step integrated with the central fixed shaft 41 of the hub 411 and the right side C-shaped snap ring 47 do axial positioning; the outer rotor 21 rotates outside the inner stator by the second right ball bearing 26 and the second left ball bearing 27 on the fixed shaft 41 in the center of the hub. The hub rotating shaft 23 is locked in the outer rotor groove 28 by the screw 24, and rotates together with the outer rotor 21 as an input rotating member. The hub rotating shaft 23 includes an eccentric rotating shaft 25, both of which are integrated or integrally formed.

The first-order involute small-tooth-difference planetary gear reduction mechanism includes a planetary gear 11 with four or six pin holes 13, a ring gear 12 fixed to the ring gear bracket 42 by screws 17, and four or six pins. 15 and the output intermediary 14 of the self-lubricating bushing 16 that is sleeved on the pin. The electric bicycle booster device of the outer rotor hub motor of the first-order involute less tooth difference planetary gear speed reduction transmission mechanism of the present invention, the movement sequence of deceleration and boosting is the hub shaft 23 locked to the outer rotor 21 of the hub motor The eccentric rotating shaft 25 drives the planetary gear 11 to perform planetary motion around the ring gear 12, and through the pin hole 13 on the planetary gear 11 and the pin 15 on the output intermediary member 14 and the hole pin of the self-lubricating bushing 16, the constant speed is engaged. The mechanism transmits the rotational speed of the planetary gear 11 to the output intermediary 14 at the same rotation axis as the outer rotor 21 at a constant speed, and then the hub shell is driven by the output intermediary 14 that is interference-fitted in the shell main body 31 to rotate, because the hub shell is borrowed The spokes are connected to the wheel frame, and finally the hub shell drives the wheel rim for output rotation.

The hub shell performs output rotary motion on the central fixed shaft 41 of the hub through the right one ball bearing 35 and the left one ball bearing 36 respectively.

To sum up, the first-order involute less-tooth-difference planetary gear reduction mechanism for rotor hub motors other than the embodiment of the present invention has the advantages of achieving high reduction ratio, high mechanical efficiency and boosting boosting effect with smaller gears. Compared with the conventional technology such as the centering gear reducer used in the outer rotor hub motor on the market, it obviously has the function of increasing and is progressive. In addition, the present invention has not been seen in publications before the application, and its novelty Sex is also beyond doubt. This creation complies with the provisions of the Patent Law. I would like to file an application for an invention patent in accordance with the law. I would like to pray for the review and grant the patent. It is really convenient.

11: Planetary gear

12: ring gear

13: pin hole

14: Output middleware

15:pin

16: Self-lubricating bushing

17: screw

21: Outer rotor

22: Inner stator

23: hub shaft

24: screw

25: Eccentric shaft

26: The second right ball bearing

27: The second left ball bearing

28: Outer rotor groove

31: shell body

32: Shell right side cover

33: Shell left cover

34: screw

35: The right ball bearing

36: left one ball bearing

37:Right seal

38:Left seal

41: hub center fixed axis

411: fixed axis ladder

42: ring gear bracket

43:Left flat key

44: C-shaped buckle on the left

45: Left two C-shaped buckle

46: Right side flat key

47:C-shaped buckle on the right side

Claims (1)

An electric bicycle booster device with a first-order involute small-tooth-difference planetary gear reduction transmission mechanism and an external rotor hub motor, including: supporting and connecting components, including hub center fixed shaft, which can be connected to the front fork or rear of the frame On the fork; the hub shell includes the shell main body, the right side cover of the shell and the left side cover of the shell. The outer rotor hub motor includes an outer rotor, an inner stator installed on the inner side of the outer rotor, and a hub shaft with an eccentric shaft. In addition to interference fit between the inner stator and the hub center shaft, and use The flat key is used for circumferential positioning, and the ladder and C-shaped buckle integrated with the center of the hub are used for axial positioning; the first-order involute planetary gear reduction mechanism with small tooth difference includes planetary gears with four or six pin holes, A ring gear with ring-shaped internal teeth, and an output intermediary with four or six pins and self-lubricating bushings, which transmit the rotational motion of the outer rotor to the hub shell with a high reduction ratio; characterized by: one tooth In addition to the interference fit between the ring bracket and the central fixed shaft of the hub, the flat key is used for circumferential positioning and the two C-shaped buckles are used for axial positioning. The ring gear is fixed to the ring gear bracket by a screw lock as a fixing , the eccentric shaft of the hub shaft locked in the groove of the outer rotor by screws is used as the input rotating member, and the input rotating member is connected by the left two ball bearings and the right two ball bearings located on both sides of the outer rotor and on the fixed axis of the hub center. The bearing is used as support, and drives the planetary gear with only one tooth difference from the ring gear to perform planetary motion around the fixed ring gear, and through the pin hole on the planetary gear, the pin on the output intermediate piece and the hole of the self-lubricating bushing The pin joint method transmits the speed of the planetary gear to the phase of the outer rotor at a constant speed. The output intermediary part co-rotating with the axis of rotation drives the hub shell to rotate through the output intermediary part interference fit in the main body of the shell.

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