A planetary gear assembly with a clutch as a bracket

Abstract

The present invention discloses a planetary gear assembly with a clutch as a support, comprising a clutch and several planetary gears. The clutch comprises an outer ring and an inner ring, and each planetary gear is mounted on a corresponding planetary shaft, which is fixed to the outer ring of the clutch. The planetary gears are all duplex gears, comprising a coaxially arranged large gear and small gear, with the small gear facing the clutch. The assembly is characterized in that the outer ring end face of the clutch has a clearance cavity corresponding to each planetary gear for its small gear to be embedded, and the outer circumference of the outer ring has an opening corresponding to each clearance cavity, so that the outer peripheral teeth of the small gears can radially protrude from the outer ring. The present invention has a smaller axial dimension and a more compact structure, and can be adapted to motors with a smaller overall axial dimension design and a more compact internal space.

Description

Technical Field

[0001] The invention relates to a planetary gear assembly with a clutch as a support. Background Art

[0002] Both the planetary reduction mechanism and the clutch are key components of the motor transmission mechanism in hub motors or mid-mounted motors. The planetary reduction mechanism primarily consists of a planetary gear assembly and a sun gear. The multiple planetary gears in the planetary gear assembly are mounted on a bracket via planetary shafts and then mesh with the sun gear on the motor's rotor output. The clutch is typically connected to the output of the planetary reduction mechanism and then assembled with the motor's output transmission components, such as the ring gear inside the hub motor or the chainring output mechanism of a mid-mounted motor.

[0003] In the original motor transmission mechanism, the clutch is usually assembled separately from the planetary reduction mechanism. However, with the improvement of technology, more and more motor products are now integrating the planetary gear assembly in the planetary reduction mechanism with the clutch in order to simplify the structure of the internal transmission mechanism and make it more compact. In this assembly structure, the clutch is also used as a bracket to support the assembly of the planetary gear.

[0004] Taking a conventional through-shaft hub motor as an example, the motor (including the stator and rotor), planetary reduction mechanism, and clutch are all assembled in sequence along this through-shaft. The clutch consists of an outer ring and an inner ring, the inner ring of which is fixed to the through-shaft, while the planetary shaft at the center of the planetary gear is directly fixed to the outer ring of the clutch. A sun gear, which is mounted on the through-shaft, is fixed to the output end of the motor's rotor. This sun gear is connected to the ring gear fixed to the inside of the hub shell through several planetary gears in the planetary reduction mechanism. In further refinement, the planetary gears are usually made into an integral double gear, with the large gear meshing with the sun gear and the small gear meshing with the ring gear.

[0005] It can be said that many companies in the industry have already produced the above-mentioned planetary gear assembly with a clutch as a standard part so that it can be quickly adapted to the appropriate motor transmission mechanism. However, in actual use, the existing planetary gear assembly has exposed the following problems:

[0006] Because the planetary gears and clutch are simply assembled axially, the axial dimensions of this type of planetary gear assembly, with the clutch as a support, are not optimized or reduced. Consequently, it cannot be adapted to motors with a small overall axial dimension and compact internal space. In the prior art, a type of motor manufactured and used in electric power-assisted road bicycles often has higher production requirements in terms of overall weight, volume, structural strength, and output power.

[0007] Furthermore, it's worth noting that, to further reduce component mass, existing planetary gears typically utilize duplex plastic gears, manufactured from a single piece of plastic, such as POM (polyoxymethylene), PEEK (polyetheretherketone), and nylon plastics like PA66 and PA46. However, this inevitably leads to a decrease in structural strength. To compensate for this shortcoming, current practice often involves making these duplex plastic gears thicker and larger to enhance structural strength. However, increasing the diameter of the larger gear in the duplex gear reduces its speed ratio to the sun gear at the rotor's output, ultimately reducing the motor's overall output power.

[0008] Moreover, as the overall size of the planetary gear increases, it needs to be adapted to a motor with a larger outer diameter, which ultimately leads to an increase in the corresponding motor volume, increased material usage, increased weight, and higher costs. Summary of the Invention

[0009] The purpose of the present invention is to provide a planetary gear assembly with a clutch as a bracket, which has a smaller axial size and a more compact structure, and can be adapted to a motor with a smaller overall axial size design and a more compact internal space.

[0010] The technical solution of the present invention is: a planetary gear assembly with a clutch as a support, including a clutch and several planetary gears, the clutch including an outer ring and an inner ring, each planetary gear is arranged on a corresponding planetary shaft, and the planetary shaft is fixed to the outer ring of the clutch; the planetary gears are all double gears, including a large gear and a small gear arranged coaxially, and the small gear is arranged toward the clutch; it is characterized in that a clearance cavity for the small gear to be embedded is provided on the end face of the outer ring of the clutch corresponding to each planetary gear, and an opening is provided on the outer periphery of the outer ring corresponding to each clearance cavity, so that the outer peripheral tooth portion of the small gear can radially protrude from the outer ring.

[0011] Furthermore, the present invention sets the large and small gears of the planetary gear separately, wherein the large gear is a plastic gear and the small gear is a metal gear, and an extended shaft sleeve is integrally provided in the center to fix the large gear.

[0012] Furthermore, the large gear is injection-molded and fixed to the periphery of the extension sleeve of the small gear, or the large gear is embedded in the periphery of the extension sleeve of the small gear through a keyway structure.

[0013] Furthermore, the extension sleeve of the pinion gear is assembled on the planetary shaft through a plurality of planetary bearings.

[0014] Preferably, the planetary bearings of the present invention are sliding bearings. Compared to deep groove ball bearings, sliding bearings can further reduce the radial dimensions of the planetary gears, thus reducing the overall radial dimensions of the present invention. Furthermore, when adapted to a motor, they can increase the speed ratio between the large gear and the sun gear at the motor rotor output end, thereby increasing the overall motor power. This also reduces the size of the motor to which they are adapted.

[0015] Furthermore, the planetary gears in the present invention are distributed in a centrosymmetrical manner about the center of the clutch, and the number of the planetary gears is more than three.

[0016] Furthermore, the inner circumference of the inner ring of the clutch in the present invention is milled with a positioning groove for assembly and fixation to a shaft milled with splines, such as quick assembly and fixation to the through shaft of a hub motor or the center shaft of a mid-mounted motor.

[0017] The present invention is practically used as a component of an existing motor transmission mechanism. For example, a conventional through-shaft hub motor comprises a through-shaft and a hub housing mounted on the through-shaft at both ends via housing bearings. The hub housing houses a movement, a sun gear, and the planetary gear assembly of the present invention, which are assembled sequentially along the through-shaft. The movement employs an inner stator and outer rotor structure. The sun gear is fixed to the rotor and sleeved on the through-shaft. The sun gear is then connected to a ring gear fixed to the inner side of the hub housing via the planetary gears of the present invention.

[0018] During assembly, the clutch's inner ring is fixed to a through-shaft. The planetary gears are made of plastic and mesh with the sun gear. The pinions are metal gears, each with an integral extended sleeve to secure the gear. The clutch's outer ring has recessed pockets on its end faces, corresponding to the planetary gears, for the pinions to fit into. Openings are provided on the outer circumference of each recessed pocket, allowing the outer teeth of the pinions to protrude radially and mesh with the ring gear. In this type of motor, the ring gear is often also made of plastic to further reduce weight and minimize noise when meshing with the metal pinions.

[0019] It should be noted that the plastic used in the large gear of the present invention can be any commonly used material in the industry, such as POM (polyoxymethylene) plastic, PEEK (polyetheretherketone) plastic, and nylon plastic such as PA66 and PA46.

[0020] As for the pinion of the metal gear, its metal material can also be any commonly used material in the industry, such as alloy steels such as 40Cr, 45Cr, 20CrMnTi, as well as conventional copper alloys (such as brass) and aluminum alloys. Its forming methods can be milling, forging, cold extrusion, drawing and powder metallurgy.

[0021] The advantages of the present invention are:

[0022] 1. Because the present invention features recessed pockets on the outer end face of the clutch ring, corresponding to the pinions of each planetary gear, it can further reduce the overall axial length compared to existing products, resulting in a more compact structure. This allows it to be adapted for motors with smaller overall axial dimensions and more compact internal spaces. Similarly, the planetary gear assembly of the present invention facilitates the design of corresponding motors with smaller dimensions and more compact internal structures, thereby saving materials, reducing weight, and lowering production costs.

[0023] 2. The planetary gears of this invention differ from existing integrally manufactured plastic duplex gears in that their large and small gears are arranged separately. The large gear is a plastic gear, which reduces the overall weight of the planetary gear, while the small gear is a metal gear, secured to the large gear by an integrally formed extended sleeve. This structure ensures the small gear's inherent strength while also providing a certain degree of support for the large gear. This eliminates the need for increasing the outer diameter and thickness of the large gear to enhance strength, as is conventionally done. Instead, the outer diameter of the large gear can be further reduced, thereby ensuring a higher speed ratio with the sun gear at the rotor output end of the motor to which it is adapted, thereby increasing the overall output power of the motor and making this type of motor more suitable for the application requirements of electric power-assisted road bicycles.

[0024] 3. Similarly, because the metal pinion in the planetary gear structure design of the present invention can provide sufficient supporting strength for the large gear, the outer diameter and thickness of the large gear can be further reduced. This helps to reduce the radial and axial dimensions of the entire motor to which it is adapted, thereby reducing the volume and weight of the entire motor, making this type of motor more suitable for the application requirements of road electric power-assisted bicycles.

[0025] 4. In this invention, the planetary shafts utilize sliding bearings to support the pinion gears and their extension sleeves. Compared to deep groove ball bearings, these bearings can further reduce the radial dimensions of the planetary gears, thus reducing the overall radial dimensions of the present invention. Furthermore, when adapted to a motor, this increases the speed ratio between the large gear and the sun gear at the motor's rotor output, thereby increasing overall motor power. This also reduces the size of the motor to which it is adapted. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0027] Figure 1 It is the front view of the present invention;

[0028] Figure 2 for Figure 1 Right view of;

[0029] Figure 3 for Figure 1AA cross-section of

[0030] Figure 4 for Figure 1 Schematic diagram of the three-dimensional structure of the clutch (with planetary shaft);

[0031] Figure 5 for Figure 1 Front view of the middle clutch;

[0032] Figure 6 This is a cross-sectional view of the present invention in use on a through-axle hub motor.

[0033] Among them: 1. Clutch; 101. Outer ring; 101a. Clearance cavity; 101b. Opening; 102. Inner ring; 102a. Positioning groove; 2. Planetary gear; 201. Large gear; 202. Small gear; 202a. Extension sleeve; 3. Planetary shaft; 4. Planetary bearing; 5. Through shaft; 6. Housing bearing; 7. Hub housing; 8. Stator; 9. Rotor; 10. Sun gear; 11. Ring gear. DETAILED DESCRIPTION

[0034] Example: The following combination Figures 1 to 6 The specific embodiment of the planetary gear assembly with the clutch as the bracket provided by the present invention is described as follows:

[0035] First, as Figure 1 As shown, this embodiment comprises a clutch 1, three planetary gears 2, three planetary shafts 3, and six planetary bearings 4. The clutch 1, like conventional technology, has an outer ring 101 and an inner ring 102. Each planetary gear 2 is mounted on a corresponding planetary shaft 3, which is vertically fixed to the outer ring 101 of the clutch 1. The three planetary gears 2 are distributed symmetrically about the center of the clutch 1.

[0036] Combine Figures 2 to 5 As shown, the planetary gears 2 are all duplex gears, comprising a coaxially arranged large gear 201 and small gears 202, with the small gears 202 facing the clutch. The core improvement of the present invention lies in the fact that the outer ring 101 of the clutch 1 has a corresponding clearance cavity 101a on the end surface of each planetary gear 2, into which the small gears 202 are inserted. Furthermore, the outer circumference of the outer ring 101 has openings 101b corresponding to each clearance cavity 101a, allowing the outer peripheral teeth of the small gears 202 to protrude radially from the outer ring 101.

[0037] Meanwhile, the large gear 201 in this embodiment is a plastic gear, and the small gear 202 is a metal gear, with an extension sleeve 202a integrally provided in the center thereof to fix the large gear 201. In this embodiment, the large gear 201 is injection-molded and fixed to the outer periphery of the extension sleeve 202a of the small gear 202.

[0038] The extension sleeve 202a of each pinion 202 is assembled on the planetary shaft 3 via two planetary bearings 4, and the planetary bearings 4 are sliding bearings.

[0039] At the same time, in this embodiment, the inner circumference of the inner ring 102 of the clutch 1 is milled with a positioning groove 102a, such as Figure 1 、 Figure 4 and Figure 5 shown.

[0040] The present embodiment is further described below in conjunction with the application:

[0041] This planetary gear assembly with the clutch as the bracket is actually used as a component of the existing motor transmission mechanism. Figure 6 As shown, specifically, the present invention is applied to a known through-shaft hub motor as an example. This motor comprises a through-shaft 5 and a hub housing 7, both ends of which are mounted on the through-shaft 5 via housing bearings 6. The hub housing 7 houses a movement, a sun gear 10, and the planetary gear assembly of the present invention, which are assembled in sequence along the through-shaft 5. The movement employs an inner stator 8 and outer rotor 9 structure. The sun gear 10 is fixed to the rotor 9 and sleeved on the through-shaft 5. It is connected to a ring gear 11 fixed to the inner side of the hub housing 7 via the planetary gears 2 of the present invention.

[0042] During assembly, the inner ring 102 of the clutch 1 is secured to the through-shaft 5 by means of a positioning groove 102a thereon that engages with a key milled on the through-shaft 5. The large gear 201 of the planetary gears 2 is a plastic gear that meshes with the sun gear 10, while the small gears 202 are metal gears with an integral extended sleeve 202a at their center to secure the large gear 201. The outer ring 101 of the clutch 1 has recessed pockets 101a on its end surface corresponding to each planetary gear 2, allowing the small gears 202 to fit into the pockets. Openings 101b are provided on the outer periphery of the outer ring 101, corresponding to each recessed pocket 101a, to allow the outer teeth of the small gears 202 to protrude radially, allowing them to mesh with the ring gear 11. In this type of motor, the ring gear 11 is often also made of plastic to further reduce weight and reduce noise when meshing with the metal small gears 202. Similarly, the meshing of the large plastic gear 201 with the metal sun gear 10 at the output end of the conventional rotor 9 can also reduce noise, thereby greatly reducing the overall operating noise of the through-axle hub motor.

[0043] In this embodiment, the large gear 201 and the ring gear 11 as plastic gears are actually produced using the commonly used nylon plastic PA66, while the small gear 202 and the sun gear 10 as metal gears are manufactured using the 40Cr alloy steel commonly used in the industry through a powder metallurgy process.

[0044] Since this embodiment provides recessed cavities 101a for embedding the pinions 202 of the planetary gears 2 on the end faces of the outer ring 101 of the clutch 1, the overall axial length can be further reduced compared to existing products, making the structure more compact. This allows the embodiment to be adapted to motors with smaller overall axial dimensions and more compact internal spaces. Similarly, the planetary gear assembly of the present invention is also more conducive to designing corresponding motor products with smaller volumes and more compact internal structures, such as the above-mentioned through-axle hub motor, so as to save production materials, reduce weight, and lower production costs.

[0045] Moreover, the planetary gear 2 in this embodiment is different from the existing integrally manufactured plastic double gear. Its large gear 201 and small gear 202 are separately arranged. The large gear 201 uses a plastic gear to reduce the overall weight of the planetary gear 2, while the small gear 202 uses a metal gear and is fixed to the large gear 201 by an extended shaft sleeve 202a integrally provided thereon. This structure makes the small gear 202 itself strong while also providing a certain supporting strength to the large gear 201, so that the large gear 201 does not need to increase its outer diameter and thickness to increase its strength as in conventional technology. On the contrary, its outer diameter can be further reduced, thereby ensuring that it has a higher speed ratio with the sun gear 10 at the output end of the rotor 9 of the above-mentioned through-axle hub motor to which it is adapted, thereby improving the overall output power of the motor, so that this type of motor better meets the application requirements of road electric power-assisted bicycles.

[0046] Similarly, since the metal small gear 202 in the planetary gear structure design of this embodiment can provide sufficient supporting strength to the large gear 201, the outer diameter and thickness of the large gear 201 can be further reduced, which is conducive to reducing the radial and axial dimensions of the entire through-axle hub motor such as the above-mentioned one, thereby reducing the volume and weight of the entire motor, making this type of motor more suitable for the application requirements of road electric power-assisted bicycles.

[0047] Furthermore, sliding bearings are used on the planetary shafts 3 to support the pinion gears 202 and their extension sleeves 202a. Compared to deep groove ball bearings, the use of sliding bearings can further reduce the radial dimensions of the planetary gears 2, thus reducing the overall radial dimensions of the present invention. Furthermore, when adapted to a motor, the speed ratio between the large gear 201 and the sun gear 10 at the output end of the motor rotor 9 can be increased, thereby increasing the overall motor power. This also reduces the size of the motor to which it is adapted.

[0048] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the present invention and implement it accordingly. They are not intended to limit the scope of protection of the present invention. Any modifications made within the spirit of the main technical solution of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A planetary gear assembly with a clutch as a support, comprising a clutch (1) and a plurality of planetary gears (2), wherein the clutch (1) comprises an outer ring (101) and an inner ring (102), and each planetary gear (2) is arranged on a corresponding planetary shaft (3), and the planetary shaft (3) is fixed to the outer ring (101) of the clutch (1); the planetary gears (2) are all double gears, comprising a large gear (201) and a small gear (202) arranged coaxially, and the small gear (202) is arranged toward the clutch; and it is characterized in that The outer ring (101) of the clutch (1) has a recessed cavity (101a) on the end surface thereof corresponding to each planetary gear (2) for embedding its pinion (202), and an opening (101b) is provided on the outer periphery of the outer ring (101) corresponding to each recessed cavity (101a) so that the outer peripheral teeth of the pinion (202) can protrude radially from the outer ring (101); the large gear (201) is a plastic gear, and the small gear (202) is a metal gear, and an extension sleeve (202a) is integrally provided at the center thereof to fix the large gear (201).

2. A planetary gear assembly with a clutch as a bracket according to claim 1, characterized in that The large gear (201) is injection-molded and fixed to the periphery of the extension sleeve (202a) of the small gear (202), or the large gear (201) is embedded in the periphery of the extension sleeve (202a) of the small gear (202) through a keyway structure.

3. A planetary gear assembly with a clutch as a bracket according to claim 1, characterized in that The extended shaft sleeve (202a) of the pinion (202) is assembled on the planetary shaft (3) via a plurality of planetary bearings (4).

4. A planetary gear assembly with a clutch as a bracket according to claim 3, characterized in that The planetary bearing (4) adopts a sliding bearing.

5. The planetary gear assembly with a clutch as a bracket according to claim 1, characterized in that The planetary gears (2) are distributed in a centrosymmetrical manner about the center of the clutch (1), and the number of the planetary gears (2) is more than three.

6. A planetary gear assembly with a clutch as a bracket according to claim 1, characterized in that A positioning groove (102a) is milled on the inner circumference of the inner ring (102) of the clutch (1).

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