Centrally-mounted motor gear transmission mechanism and electric power-assisted bicycle driving system

Abstract

The utility model relates to a middle motor gear transmission mechanism and an electric power-assisted bicycle driving system. The middle motor gear transmission mechanism comprises a second-stage input gear, a second-stage output gear, a third-stage input gear, a third-stage output gear and a wedge block type overrun clutch, and limiting check rings are arranged above and below the second-stage output gear respectively, so that the second-stage output gear is axially limited and longitudinally supported; under the condition that axial positioning of the secondary output gear is guaranteed, most longitudinal vibration generated when the secondary input gear and the secondary output gear are meshed and loaded is borne and partially absorbed at the same time, the gear meshing precision is improved to the maximum degree, and the purposes of reducing vibration and noise and guaranteeing the service life of a gear driving system are achieved. According to the electric power-assisted bicycle driving system, by applying the middle motor gear transmission mechanism, high precision of meshing of the second-stage gear can be guaranteed, and the effects of reducing vibration, lowering noise and guaranteeing stable operation are achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of mid-drive motors for electric assist bicycles, and particularly relates to a vibration-damping mid-drive motor gear transmission mechanism and an electric assist bicycle drive system. Background Art

[0002] A mid-drive motor is a type of electric motor commonly used in electric assist bicycles. Different from rear-wheel motors and front-wheel motors, a mid-drive motor is an electric motor installed in the middle of the bicycle frame. It drives the rear wheel sprocket through a belt or a chain, thereby driving the wheel to rotate. The working principle of the mid-drive motor gear transmission mechanism is that under the drive of the motor, the gears mesh with each other, and multiple-stage gears drive layer by layer, and finally the power is transmitted to the vehicle.

[0003] Chinese Patent CN211076241U (Publication Date: November 1, 2019) discloses a mid-drive motor transmission mechanism and an electric assist vehicle drive system. The mid-drive motor transmission mechanism includes a first-level drive shaft and a second-level drive shaft. A first drive gear and a second drive gear are provided on the first-level drive shaft. The number of teeth of the first drive gear is greater than that of the second drive gear. The first drive gear is configured to be in transmission connection with the output end of the mid-drive motor; a third drive gear and a fourth drive gear are provided on the second-level drive shaft. The number of teeth of the third drive gear is greater than that of the fourth drive gear. The third drive gear meshes with the second drive gear, and the fourth drive gear is configured to be in transmission connection with the output shaft. This mid-drive motor transmission mechanism can achieve multi-stage speed change, and has a small volume and is easy to install. The electric assist vehicle drive system provided by the utility model can achieve multi-stage speed change and has a small volume by applying the above mid-drive motor transmission mechanism.

[0004] Chinese Patent CN212500785U (Publication Date: June 9, 2020) discloses a bicycle and an automatic grease compensation mechanism for a mid-drive motor gear of a bicycle, including a motor housing, an oil collecting cover, a gear reduction system and a gearbox housing; a motor body and a controller circuit board electrically connected to the motor body are provided in the motor housing. The gear reduction system includes a motor shaft end gear, a first-level double gear, a second-level double gear and an output shaft gear. The motor body is connected to the motor shaft end gear through the motor shaft. The motor shaft end gear meshes with the large gear of the first-level double gear. The small gear of the first-level double gear meshes with the large gear of the second-level double gear. The small gear of the second-level double gear meshes with the output shaft gear. The oil collecting cover is located outside the motor shaft end gear, the first-level double gear and the second-level double gear. The utility model solves the problem of increased noise after the motor has been used for a long time by collecting grease by using an oil collecting cover and a grease pushing plate, and a structure in which a micro electromagnetic coil pushes the grease pushing plate to compensate for the grease thrown out due to the high-speed rotation of the gears.

[0005] Chinese Patent CN214823908U (Publication Date: July 30, 2021) discloses a mid-mounted motor drive mechanism, an electric assist vehicle drive system, and an electric assist vehicle. The mid-mounted motor drive mechanism includes a central shaft, an input gear, an output gear, a clutch, and a central shaft support bearing. The input gear is used to mesh with the output gear of the reducer, and the output gear is used to transmit power to the chainring; the clutch is sleeved on the central shaft and is in transmission connection with the central shaft; the output gear is sleeved on the clutch and is in transmission connection with the clutch; the stepped mating surfaces of the central shaft support bearing and the central shaft are respectively located at both ends of the output gear, and are used to limit the output gear; by fixing the input gear on the central shaft and using the stepped mating surface and the central shaft support bearing on the central shaft to limit the output gear, it is possible to achieve the positioning of the input gear and the output gear without increasing the size of the central shaft, ensure accurate positioning, reduce transmission noise.

[0006] Currently, in the power transmission of the mid-mounted motor gear drive mechanism, through multiple-stage transmission components, multiple-stage transmission generates vibration. When meshing at the intermediate stage, there will be a certain amount of eccentric load, resulting in a large vibration frequency, generating a certain amount of noise, affecting the gear life, and causing vibration in the drive system. Therefore, a new type of mid-mounted motor gear drive mechanism is needed to solve the above problems. Summary of the Utility Model

[0007] To solve the above technical problems, on the one hand, the present utility model provides a mid-mounted motor gear drive mechanism, which can improve the meshing accuracy of gears, reduce the vibration generated by gears, reduce noise, and extend the service life of the drive mechanism. On the other hand, it provides an electric assist bicycle drive system. By applying the above mid-mounted motor gear drive mechanism, it can reduce the vibration of the drive system, reduce system noise, ensure the stable operation of the drive system, and extend the service life of the drive system.

[0008] The technical solution of the present utility model is as follows:

[0009] A mid-mounted motor gear drive mechanism, which includes a secondary input gear, a secondary output gear, a tertiary input gear, a tertiary output gear, and a sprag overrunning clutch;

[0010] The secondary input gear and the secondary output gear of the mid-mounted motor gear drive mechanism mesh with each other during the movement process, and the power is transmitted from the secondary input gear to the secondary output gear;

[0011] The secondary output gear, the sprag overrunning clutch, and the tertiary input gear of the mid-mounted motor gear drive mechanism are nested layer by layer, and the power is transmitted to the central shaft of the tertiary input gear through the sprag overrunning clutch;

[0012] The central shaft of the three-stage input gear of the central motor gear transmission mechanism meshes with the three-stage output gear, and the power is transmitted from the three-stage input gear to the three-stage output gear.

[0013] Further, there is a first bearing and a second bearing above and below the two-stage input gear of the central motor gear transmission mechanism;

[0014] Further, the first bearing and the second bearing on the two-stage input gear of the central motor gear transmission mechanism play a role in supporting and fixing the two-stage input gear;

[0015] Further, there is a third bearing and a fourth bearing above and below the three-stage input gear of the central motor gear transmission mechanism;

[0016] Further, the first bearing, the second bearing, the third bearing and the fourth bearing of the central motor gear transmission mechanism are deep groove ball bearings.

[0017] Further, there is a first limit retaining ring and a second limit retaining ring above and below the two-stage output gear of the central motor gear transmission mechanism.

[0018] Further, the first limit retaining ring of the central motor gear transmission mechanism is located between the three-stage input gear and the wedge-type overrunning clutch, longitudinally supporting the two-stage output gear to ensure the verticality of the installation of the two-stage output gear;

[0019] Further, the upper surface of the first limit retaining ring is flush with the upper surface of the two-stage output gear (2), and the outer circular surface of the first limit retaining ring fits with the inner circular surface of the two-stage output gear (2); the cross section of the first limit retaining ring is rectangular.

[0020] Further, the second limit retaining ring is located between the three-stage input gear, the third bearing and the two-stage output gear.

[0021] Further, the second limit retaining ring is a non-metallic component with a certain plasticity, which can absorb a large part of the longitudinal vibration generated when the two-stage input gear and the two-stage output gear are meshed under load.

[0022] Further, the cross section of the second limit retaining ring is L-shaped.

[0023] An electric assist bicycle drive system, the electric assist bicycle drive system includes a central motor, and the central motor uses the above-mentioned central motor gear transmission mechanism to transmit power to the vehicle.

[0024] The beneficial effects obtained by the present utility model:

[0025] 1. In the middle-mounted motor gear transmission mechanism provided by the present utility model, one limiting retaining ring is provided above and below the secondary output gear. Among them, the first limiting retaining ring longitudinally supports the secondary output gear, ensuring the verticality of the installation of the secondary output gear, improving the gear meshing accuracy, reducing the amplitude, ensuring the one-way power transmission, and making the service life of the gear drive system meet the design requirements. The second limiting retaining ring undertakes most of the longitudinal vibrations generated when the secondary input gear and the secondary output gear are engaged under load, and absorbs part of the longitudinal vibrations, reducing the amplitude and noise.

[0026] 2. The electric assist bicycle drive system provided by the present utility model can achieve the effects of reducing vibration, reducing noise, and ensuring smooth operation by applying the above middle-mounted motor gear transmission mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0028] Figure 1 It is a structural diagram of the middle-mounted motor gear transmission mechanism provided by the present application;

[0029] Among them: 1-secondary input gear; 2-secondary output gear; 3-tertiary input gear; 4-tertiary output gear; 5-wedge-type overrunning clutch; 6-first bearing; 7-second bearing; 8-third bearing; 9-fourth bearing; 10-first limiting retaining ring; 11-second limiting retaining ring. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. In the following description, specific details such as specific configurations and components are provided only to assist in a comprehensive understanding of the embodiments of the present application. Therefore, those skilled in the art should clearly understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present application. In addition, for clarity and conciseness, descriptions of known functions and structures are omitted in the embodiments.

[0031] It should be understood that the "one embodiment" or "this embodiment" mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present application. Therefore, the "one embodiment" or "this embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner.

[0032] In addition, this application may repeat reference numerals and / or letters in different instances. This repetition is for the purpose of simplicity and clarity, and does not in itself indicate the relationship between the various embodiments and / or arrangements discussed.

[0033] The term "and / or" in this article is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. The term " / and" in this article describes another association relationship of associated objects, indicating that there can be two relationships. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are an "or" relationship.

[0034] The term "at least one" in this article is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, at least one of A and B can mean: A exists alone, A and B exist simultaneously, and B exists alone.

[0035] It should also be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion.

[0036] Embodiment 1:

[0037] Please refer to Figure 1 , a mid-mounted motor gear transmission mechanism, which includes a secondary input gear 1, a secondary output gear 2, a tertiary input gear 3, a tertiary output gear 4, and a wedge-type overrunning clutch 5;

[0038] The secondary input gear 1 meshes with the secondary output gear 2;

[0039] The secondary output gear 2 is internally embedded with a wedge-type overrunning clutch 5;

[0040] The tertiary input gear 3 is nested with a wedge-type overrunning clutch 5 below;

[0041] The described three - stage input gear 3 meshes with the three - stage output gear 4;

[0042] A first bearing 6 and a second bearing 7 are respectively sleeved on the upper and lower ends of the two - stage input gear 1;

[0043] A third bearing 8 and a fourth bearing 9 are respectively sleeved on the upper and lower ends of the three - stage input gear 3.

[0044] There is a first limit retaining ring 10 on the three - stage input gear 3, located above the two - stage output gear 2 and the overrunning clutch 5;

[0045] There is a second limit retaining ring 11 on the three - stage input gear 3, located between the bearing 8, the three - stage input gear 3 and the two - stage output gear 2.

[0046] The first bearing 6, the second bearing 7, the third bearing 8 and the fourth bearing 9 are deep - groove ball bearings.

[0047] The upper surface of the first limit retaining ring 10 is flush with the upper surface of the two - stage output gear 2, and the outer cylindrical surface of the first limit retaining ring 10 fits with the inner cylindrical surface of the two - stage output gear 2, playing a role in longitudinally supporting the two - stage output gear and ensuring the verticality of the installation of the two - stage output gear;

[0048] The cross - section of the first limit retaining ring 10 is rectangular.

[0049] The described second limit retaining ring 11 is a non - metallic component with a certain plasticity and can absorb a certain amount of vibration;

[0050] The cross - section of the second limit retaining ring 11 is L - shaped.

[0051] The technical effects achieved by this embodiment are: improving the accuracy of gear meshing, reducing the eccentric load generated by the meshing of the two - stage output gear and the two - stage input gear, thereby reducing the noise generated by vibration; avoiding the reduction of service life caused by abnormal meshing, etc.

[0052] Embodiment 2:

[0053] Based on the above-mentioned Embodiment 1, this embodiment mainly introduces the working principle of a mid-mounted motor gear transmission mechanism. During use, the secondary input gear 1 transmits power to the secondary output gear 2, and then transmits power to the central shaft of the tertiary input gear 3 through the overrunning clutch 5 of the wedge type. The tertiary input gear 3 meshes with the tertiary output gear 4 to transmit power to the tertiary output gear 4. Among them, the secondary input gear 1 and the secondary output gear 2 mesh with each other during the movement process. The secondary input gear 1 is supported and fixed by the bearing 6 and the bearing 7. The tertiary input gear 3 is equipped with a limit retaining ring 10 and a limit retaining ring 11. When the secondary input gear 1 and the secondary output gear 2 are engaged and loaded, a large part of the longitudinal vibration generated will be conducted to the limit retaining ring 11. Since this part is a non-metallic component and has a certain plasticity, it can absorb a certain amount of vibration. At the same time, the longitudinal support of the limit retaining ring 10 for the secondary output gear 2 can ensure the perpendicularity of the installation of the secondary output gear 2, making the meshing of the secondary input gear 1 and the secondary output gear 2 smoother, with lower noise, smaller generated amplitude, and avoiding the reduction of service life caused by abnormal meshing and the like.

[0054] Embodiment 3:

[0055] Based on the above-mentioned Embodiments 1-2, this embodiment mainly introduces an electric assist bicycle drive system. The electric assist bicycle drive system includes a mid-mounted motor. The mid-mounted motor uses a mid-mounted motor gear transmission mechanism as described in Embodiment 1 to transmit power to the vehicle. During use, the power is finally transmitted to the vehicle through the spline on the tertiary output gear 4 in the above-mentioned mid-mounted motor gear transmission mechanism to drive the vehicle.

[0056] The technical effects achieved by this embodiment are as follows: ensuring one-way transmission during the process of a mid-mounted motor gear transmission mechanism transmitting power to the vehicle, reducing the pedaling resistance when the battery of the electric assist bicycle runs out of power, reducing the vibration generated by multi-stage transmission, ensuring that the electric assist bicycle drive system rotates easily and the service life meets the design requirements.

[0057] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above description is only the specific embodiments of the present invention and is not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A mid-mounted motor gear transmission mechanism, characterized in that: It comprises a two-stage input gear (1), a two-stage output gear (2), a three-stage input gear (3), a three-stage output gear (4), and a wedge-type overrunning clutch (5); The secondary input gear (1) and the secondary output gear (2) are meshed with each other; The secondary output gear (2) is embedded with a wedge-type overrunning clutch (5); A wedge-type overrunning clutch (5) is nested below the three-stage input gear (3); The three-stage input gear (3) is meshed with the three-stage output gear (4); The upper and lower ends of the secondary input gear (1) are respectively sleeved with a first bearing (6) and a second bearing (7); The upper and lower ends of the third-stage input gear (3) are respectively provided with a third bearing (8) and a fourth bearing (9); The upper and lower ends of the secondary output gear (2) are respectively provided with a first limit retaining ring (10) and a second limit retaining ring (11).

2. A mid-mounted motor gear transmission mechanism according to claim 1, characterized in that: The first bearing (6) and the second bearing (7) sleeved on the secondary input gear (1) are deep groove ball bearings.

3. A mid-mounted motor gear transmission mechanism according to claim 1, characterized in that: The third bearing (8) and the fourth bearing (9) sleeved on the third-stage input gear (3) are deep groove ball bearings.

4. The mid-mounted motor gear transmission mechanism according to claim 1, characterized in that: The first limit ring (10) is located between the second-stage output gear (2), the wedge-type overrunning clutch (5) and the third-stage input gear (3).

5. The mid-mounted motor gear transmission mechanism according to claim 1, characterized in that: The second limit ring (11) is located between the bearing (8), the second-stage output gear (2) and the third-stage input gear (3).

6. A mid-mounted motor gear transmission mechanism according to claim 1 or 4, characterized in that: The lower surface of the first limit stop ring (10) is flush with the upper surface of the second output gear (2); the outer circumferential surface of the first limit stop ring (10) is in contact with the inner circumferential surface of the second output gear (2); and the cross section of the first limit stop ring (10) is rectangular.

7. A mid-mounted motor gear transmission mechanism according to claim 1 or 5, characterized in that: The second limit retaining ring (11) is a non-metallic component.

8. A mid-mounted motor gear transmission mechanism according to claim 1 or 5, characterized in that: The second limiting retaining ring (11) has a certain plasticity.

9. A mid-mounted motor gear transmission mechanism according to claim 1 or 5, characterized in that: The cross section of the second limiting retaining ring (11) is L-shaped.

10. An electric power-assisted bicycle driving system, characterized in that: The electric-assisted bicycle driving system includes a mid-mounted motor, and the mid-mounted motor adopts a mid-mounted motor gear transmission mechanism as described in any one of claims 1 to 9, and the gear transmission mechanism transmits power to the vehicle.

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