Driving device and planetary gear box thereof

Abstract

The utility model relates to a driving device and a planetary gear box thereof. The planetary gear box comprises a sun gear (81), a plurality of planet gears (82) surrounding the sun gear (81), an inner gear ring (83) surrounding the planet gears (82) and a gear carrier (85) for installing the planet gears (82). A tooth (8101) of the sun gear (81) comprises a tooth crest (8103) and two tooth surfaces (8105), and the two tooth surfaces (8105) are located on the two sides of the tooth crest (8103) respectively. The part, close to the tooth crest (8103), of the tooth surface (8105) is trimmed to form an outer arch cambered surface; and the teeth (8201) of the planet gear (82) and the teeth of the inner gear ring (83) are the same as the teeth (8101) of the sun gear (81) in size and shape. By means of the gear, the smoothness of tooth surfaces can be improved, the contact area of the tooth surfaces is increased, smooth transition is achieved, the meshing degree is obviously improved, abrasion between gears in the working process is reduced, noise and vibration are correspondingly reduced, and NVH is obviously improved.

Description

Technical Field

[0001] The utility model relates to the field of drives, and more specifically, to a drive device and its planetary gearbox. Background Art

[0002] With the improvement of people's living standards, the demand for household appliances such as vacuum cleaners is increasing, and the requirements are getting higher and higher. For example, the requirements for NVH (Noise, Vibration, Harshness, that is, noise, vibration, and acoustic vibration comfort) of household appliances are getting higher and higher. Therefore, new requirements are put forward for the drive devices of household appliances. Summary of the Utility Model

[0003] An object of this application is to improve the NVH of the planetary gearbox.

[0004] To this end, the utility model provides a planetary gearbox, which includes a sun gear, a plurality of planet gears surrounding the sun gear, an internal gear ring surrounding the plurality of planet gears, and a gear carrier for mounting the plurality of planet gears; the teeth of the sun gear include a tooth tip and two tooth surfaces, and the two tooth surfaces are respectively located on both sides of the tooth tip; the tooth surfaces are trimmed near the tooth tip to form an outer arched surface; the sizes and shapes of the teeth of the planet gears and the internal gear ring are the same as those of the teeth of the sun gear.

[0005] In an embodiment of the utility model, the included angle (A2) formed by the tangents of the two tooth surfaces near the tooth tip is 45 to 75 degrees.

[0006] In an embodiment of the utility model, the included angle (A2) formed by the tangents of the two tooth surfaces near the tooth tip is 55 to 65 degrees.

[0007] In an embodiment of the utility model, the outer arched surface accounts for 50% to 90% of the surface area of the tooth surface.

[0008] In an embodiment of the utility model, the outer arched surface b accounts for 70% to 85% of the surface area of the tooth surface.

[0009] In an embodiment of the utility model, along the direction away from the tooth tip, the included angle formed by the tangents of the two tooth surfaces at symmetrical positions gradually increases, the maximum value of the included angle is 45 to 75 degrees, and the minimum value is 10 to 25 degrees.

[0010] In an embodiment of the utility model, along the direction away from the tooth tip, the included angle formed by the tangents of the two tooth surfaces at symmetrical positions gradually increases, the maximum value of the included angle is 55 to 65 degrees, and the minimum value is 12 to 20 degrees.

[0011] In an embodiment of the present utility model, the planetary gearbox includes two-stage reduction. Each stage of reduction includes a corresponding sun gear, a plurality of planet gears, and a gear carrier for mounting the plurality of planet gears; the sun gear of the second-stage reduction is driven by the gear carrier of the first-stage reduction; the planet gears of the two-stage reduction are meshed with the same internal gear ring.

[0012] On the other hand, the present utility model provides a driving device, which includes a motor and also includes the planetary gearbox as described in any one of the claims; the driving device includes a cylindrical outer shell, the motor is installed inside the outer shell, and the rotating shaft of the motor extends from the front end of the motor; the planetary gearbox is installed inside the outer shell, the planetary gearbox is located at the front end of the motor, and is positioned and aligned with the motor under the constraint of the outer shell to receive the output of the rotating shaft.

[0013] In an embodiment of the present utility model, the driving device includes a plurality of first radial connectors, a plurality of second radial connectors, a front end cover and a rear end cover that are at least partially received inside the outer shell. The plurality of first radial connectors pass through the outer shell and are fixedly connected to the rear end cover, and the plurality of second radial connectors pass through the outer shell and are fixedly connected to the front end cover; the planetary gearbox and the motor are respectively limited by the front end cover and the rear end cover and fixedly received inside the outer shell.

[0014] Implementing the present utility model can improve the tooth surface finish, increase the tooth surface contact area and achieve smooth transition, significantly improve the meshing degree, reduce the wear between gears during the working process, and correspondingly reduce the noise and vibration, and significantly improve the NVH. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] To further disclose the specific technical content of this case, please first refer to the drawings, where:

[0016] Figure 1 is a schematic diagram of a driving device provided by an embodiment of the present utility model;

[0017] Figure 2 is Figure 1 an exploded schematic diagram of the driving device shown;

[0018] Figure 3 is Figure 1 a longitudinal sectional schematic diagram of the driving device shown;

[0019] Figure 4 and Figure 5 is Figure 1 exploded schematic diagrams of the driving device shown from different angles;

[0020] Figure 6 is Figure 1 an exploded schematic diagram of the driving device shown after removing the outer shell;

[0021] Figure 7 is Figure 1 A schematic diagram of the front end cover, drive head and thrust ring of the drive device shown;

[0022] Figure 8 is Figure 1 A plan schematic diagram of the sun gear and planetary gears of the drive device shown. Specific embodiments

[0023] Next, the technical solutions in the embodiments of the present invention will be described with reference to the accompanying drawings of the present invention.

[0024] Refer to Figure 1 and Figure 2 A drive device 100 provided in an embodiment of the present invention includes a cylindrical outer shell 10, a motor 30 received in the outer shell 10, and a planetary gearbox 80. A drive head 93 is provided at the front end of the drive device 100 for connecting an external driven object (not shown in the figure), and a cable 15 of the motor 30 extends out from the rear end of the drive device 100.

[0025] The motor 30 is installed in the outer shell 10, and a rotating shaft 51 of the motor 30 extends out from the front end of the motor 30. A plurality of first radial connectors 11 pass through the outer shell 10 and are directly or indirectly fixedly connected to the motor 30.

[0026] The planetary gearbox 80 is installed in the outer shell 10, the planetary gearbox 80 is located at the front end of the motor 30, and is positioned and aligned with the motor 30 under the constraint of the outer shell 10 to receive the output of the rotating shaft 51. A plurality of second radial connectors 12 pass through the outer shell 10 and are directly or indirectly fixedly connected to the planetary gearbox 80.

[0027] In the present invention, the motor 30 and the planetary gearbox 80 are positioned by the common outer shell 10, which can improve the coaxiality of the motor 30 and the planetary gearbox 80; the outer shell 10, the motor 30, and the planetary gearbox 80 are fixed as a whole by the radial connectors 11 and 12, which can reduce the assembly complexity of the drive device 100, simplify the structure, and reduce the size.

[0028] Refer to Figure 2 and Figure 3, in this embodiment, the driving device 100 includes a front end cover 21 and a rear end cover 31. The front end cover 21 is at least partially received in the housing 10, and the rear end cover 31 is at least partially received in the housing 10. The first radial connecting member 11 passes through the housing 10 and is fixedly connected to the rear end cover 31, and the second radial connecting member 12 passes through the housing 10 and is fixedly connected to the front end cover 21. The planetary gearbox 80 and the motor 30 are respectively limited by the front end cover 21 and the rear end cover 31 and fixedly received in the housing 10. As an alternative, the front end cover 21 can be a part of the planetary gearbox 80 or fixedly connected to the planetary gearbox 80.

[0029] In this embodiment, the planetary gearbox 80 is a multi-stage reduction gear. The first stage of reduction includes a sun gear 81 fixedly sleeved on the rotating shaft 51, a plurality of planet gears 82 surrounding the sun gear 81, an internal gear ring 83 surrounding the plurality of planet gears 82, and a gear carrier 85 mounting the plurality of planet gears 82; the internal gear ring 83 is fixed to the front end cover 21 or fixedly connected to the housing 10 under the limitation of the front end cover 21. The second stage of reduction includes a sun gear 86 fixed to the gear carrier 85, a plurality of planet gears 87 surrounding the sun gear 86, and a gear carrier 88 mounting the plurality of planet gears 87. The planet gears 87 are also surrounded and meshed by the internal gear ring 83, that is, the planet gears 82 and 87 of the two stages of reduction share the same internal gear ring 83. By axially connecting multiple stages of reduction, a larger reduction ratio can be obtained and the radial dimension increase can be avoided. Understandably, the planetary gearbox 80 can adopt one stage or more stages of reduction.

[0030] Reference Figures 2 to 5 , the motor 30 includes a stator 40 and a rotor 50. The stator 40 includes an annular housing 41 and a plurality of permanent magnets 44 fixedly installed on the inner wall of the annular housing 41. A spring 45 is arranged between adjacent permanent magnets 44 to reinforce the installation of the permanent magnets 44. The rotor 50 includes a rotating shaft 51, a commutator 52 fixed to the rotating shaft 51, a rotor core 53, and a rotor winding wound around the teeth of the rotor core 53. The corresponding wire ends of the rotor winding are hung on the corresponding commutator segments of the commutator 52 and form an electrical connection. The rotor core 53 is received in the stator 40 and surrounded by the plurality of permanent magnets 44. Understandably, there is a gap 48 between the outer periphery of the rotor core 53 and the stator 40 to facilitate the rotation of the rotor 50 relative to the stator 40.

[0031] The annular housing 41 of the stator 40 is installed inside the outer housing 10. A plurality of positioning recesses 42 are provided at one end of the annular housing 41 close to the rear end cover 31. A plurality of positioning protrusions 33 are provided on the inner wall of the rear end cover 31 or the outer housing 10. The positioning protrusions 33 cooperate with the positioning recesses 42 to limit the position of the stator 40, thereby preventing the motor stator 40 from rotating. In this embodiment, the motor 30 is a permanent magnet DC brushed motor. A brush holder 32 is provided inside the rear end cover 31. The brush holder 32 is provided with a positioning protrusion 33 and a brush for supplying power to the commutator 52, etc. Understandably, the brush holder 32 can be made as an integral part of the rear end cover 31.

[0032] A plurality of positioning recesses 43 can also be provided at one end of the annular housing 41 away from the rear end cover 31. Corresponding positioning protrusions 18 are provided on the inner wall of the outer housing 10 to cooperate with the positioning recesses 43. In this embodiment, a bracket 17 is further provided inside the outer housing 10. The bracket 17 is located between the motor 30 and the planetary gearbox 80. A positioning protrusion 18 is provided on the side of the bracket 17 close to the motor 30. In this way, during assembly, the motor 30 is limited between the bracket 17 and the rear end cover 31, and the planetary gearbox 80 is limited between the bracket 17 and the front end cover 21. The rear end cover 21 and the bracket 17 are respectively provided with a first bearing 36 and a second bearing 37, which are respectively used to support the rear end and the front end of the rotating shaft 51.

[0033] A first chute 19 extending along the axial direction of the motor is provided on the inner wall of the outer housing 10. A corresponding first slide rail 84 is provided on the outer wall of the internal gear ring 83. The first slide rail 84 slides in the first chute 19 when assembling the planetary gearbox 80 to the outer housing 10. Through this structure, on the one hand, it is convenient to assemble the planetary gearbox 80, and on the other hand, it is also convenient to limit the rotation of the internal gear ring 83 relative to the outer housing 10, that is, it is convenient to keep the internal gear ring 83 fixed with the outer housing 10.

[0034] The utility model can improve the structural compactness. In order to facilitate the heat dissipation of the driving device, a cooling air duct and an impeller for generating air flow are also provided in the utility model. Specifically, the driving device 100 further includes two impellers 55, 56 fixedly sleeved on the rotating shaft 51 and housed inside the outer housing 10. The impellers 55, 56 are respectively fixed to both sides of the rotating shaft 51 and are located on both sides of the rotor 50, and can generate air flow as the rotating shaft 51 rotates. The aforementioned gap 48 between the stator 40 and the rotor 50 serves as a part of the cooling air duct. When the motor 30 works, the impellers 55, 56 rotate with the rotating shaft 51 to form an air flow, and the air flow flows through the gap 48 between the stator 40 and the rotor 50 to help the motor 30 dissipate heat.

[0035] In this embodiment, a plurality of first channels 28 are formed between the inner wall 10a of the housing 10 and the outer wall 83a of the internal gear ring 83, and the first channels 28 serve as part of the cooling air ducts for air flow. Therefore, this air flow can also help dissipate heat from the planetary gearbox 80. Preferably, the bracket 17 is provided with a plurality of through holes 20 for air flow. One side of the through holes 20 communicates with the gap 48 between the stator 40 and the rotor 50, and the other side communicates with the first channels 28 between the inner wall 10a of the housing 10 and the outer wall 83a of the internal gear ring 83.

[0036] In this embodiment, the rear end cover 31 is provided with a first air port 34 communicating with the gap 48. A plurality of second channels 29 are also formed between the front end cover 21 and the inner wall of the housing 10. One end of the second channels 29 communicates with the first channels 28, and the other end communicates with the second air port 26 at the front end of the planetary gearbox 80.

[0037] The first air port 34 and the second air port 26 are respectively connected to both ends of the cooling air duct. One of the first air port 34 and the second air port 26 serves as the air inlet, and the other serves as the air outlet. For example, the first air port 34 serves as the air inlet, and the air sequentially flows through the gap 48, the through holes 20, the first channels 28, the second channels 29, and the second air port 26. The gap 48, the through holes 20, the first channels 28, and the second channels 29 form the cooling channels.

[0038] In this embodiment, the motor 30 includes a stator 40 and a rotor 50. The stator 40 is fixedly installed on the inner wall of the housing 10, and the rotor 50 is surrounded by the stator 40 and can rotate relative to the stator 40; the gap 48 between the stator 40 and the rotor 50 serves as part of the cooling air duct; there are two impellers respectively located at both ends of the motor 30. As an alternative, there can be one impeller, installed between the motor 30 and the rear end cover 31, or installed between the motor 30 and the bracket 17.

[0039] Reference Figures 2 to 7 , the driving device 100 further includes a return spring 94, a driving rod 91, and a driving head 95. The driving rod 91 is connected to the last stage of the planetary gearbox 80 and extends outward. The driving rod 91 is driven by the planetary gearbox 80 to rotate. The driving head 95 is slidably sleeved on the outer end of the driving rod 91 and rotates along with the rotation of the driving rod 91. The driving head 95 can slide a preset distance along the driving rod 91. The return spring 94 applies a restoring force to the driving head 95 to enable the driving head 95 to be reset to a preset position.

[0040] The driving device 100 further includes a thrust ring 25 installed at the front end of the housing 10. The thrust ring 25 is used to limit the maximum distance of the driving head 95 away from the planetary gearbox 80, and the return spring 94 is used to reset the driving head 95 to the maximum distance. When the driving device 100 drives externally, the driving head 95 retracts a certain distance towards the planetary gearbox 80.

[0041] Reference Figure 6 and Figure 7 In this embodiment, a connector 92 is sleeved on the outer end of the drive rod 91, and the connector 92 is provided with a plurality of second chutes 93. The drive head 95 is sleeved on the connector 92, and a second slide rail 96 is arranged in the drive head 95 to cooperate with the second chute 93. The connector 92 can slide relative to the drive rod 91, but cannot rotate relative to the drive rod 91. In this way, when the drive rod 91 rotates, the drive head 95 is driven to rotate through the connector 92. The return spring 94 is compressed between the front end cover 21 and the connector 92. When the drive head 95 retracts towards the planetary gearbox 80, the connector 92 is driven to retract and compress the return spring 94; conversely, when the return spring 94 resets, it pushes the connector 92 outwards, thereby driving the drive head 95 to reset. As an alternative, the connector 92 can be fixed to the drive rod 91, and the drive head 95 is slidably sleeved on the connector 92. The return spring 94 is compressed between the front end cover 21 and the drive head 95.

[0042] The front end cover 21 includes an annular body 24, a hub portion 22 located in the middle of the annular body 24, and a plurality of clamping blocks 23 arranged on the outer periphery of the annular body 24. The surface of the clamping block 23 is provided with an inclined surface as a guiding surface. The hub portion 22 mounts a third bearing 38 (see Figure 3 ), and the third bearing 38 rotatably supports the drive rod 91. The thrust ring 25 is buckled onto the front end cover 21 from the outside. The thrust ring 25 includes an annular body 2501 and a plurality of connecting portions 2503 extending from one side of the annular body 2501. The connecting portion 2503 is provided with a clamping hole 2505. When the thrust ring 25 is buckled onto the front end cover 21 from the outside, the connecting portion 2503 straddles the clamping block 23 under the guidance of the inclined surface of the clamping block 23, so that the clamping block 23 slides into the clamping hole 2505 of the connecting portion 2503, thereby realizing the locking connection between the two.

[0043] The second air flow port 26 is formed between the annular body 2501 of the thrust ring 25 and the front end cover 21. The drive head 95 is in the shape of a hat and includes a cap body, a plurality of convex teeth 97 formed on the outer periphery of the cap body, and a flange 98 extending outwards from the lower end of the cap body. When the drive head 95 is in the reset state, the flange 98 is close to the annular body 2501; when the drive head 95 retracts towards the planetary gearbox 80 by a certain distance, the flange 98 is away from the annular body 2501, thereby increasing the area of the second air flow port 26 and increasing the communication area between the housing 10 and the outside. As an alternative, when the drive head 95 is in the reset state, the flange 98 abuts against the annular body 2501 to block the second air flow port 26; when the drive head 95 retracts towards the planetary gearbox 80 by a certain distance, the flange 98 is away from the annular body 2501, thereby opening the second air flow port 26 between the drive head 95 and the thrust ring 25 or forming a second air flow port 26 between the two, enabling the cooling channel to communicate with the outside.

[0044] Reference Figure 8, in order to improve the NVH of the drive device 100 and improve the driving effect, the present utility model also trims the teeth of the sun gear, planet gears, and internal gear ring. The trimming method is to trim a certain proportion of the tooth surfaces on both sides of the tooth tip of each tooth, so that the tooth surface has an outer arched surface. The following takes the sun gear 81 and planet gears 82 as examples for illustration. The tooth 8101 of the sun gear 81 includes a tooth tip 8103 and two tooth surfaces 8105, and the two tooth surfaces 8105 are respectively located on both sides of the tooth tip 8103. The tooth surface 8105 near the tooth tip 8103 is trimmed to form an outer arched surface 8105b.

[0045] Preferably, the part of the tooth surface 8105 near the tooth root is substantially a plane 8105a, and the plane 8105a is connected to the outer arched surface 8105b. The outer arched surface 8105b accounts for 50% to 90% of the surface area of the tooth surface 8105. More preferably, the outer arched surface 8105b accounts for 70% to 85% of the surface area of the tooth surface 8105.

[0046] Preferably, the included angle A2 formed by the tangents of the two tooth surfaces 8105 near the tooth tip 8103 is 45 to 75 degrees. More preferably, the included angle A2 is 55 to 65 degrees.

[0047] Preferably, along the direction away from the tooth tip 8103, the included angle formed by the tangents of the two tooth surfaces 8105 at symmetric positions gradually increases, and the maximum value of the included angle is between 45 and 75 degrees, as shown by the included angle A2 in the figure; the minimum value of the included angle is 10 to 25 degrees, as shown by the included angle A1 in the figure. More preferably, the included angle A2 is 55 to 65 degrees, and the included angle A1 is 12 to 20 degrees.

[0048] The size and shape of the tooth 8201 of the planet gear 82 are the same as those of the tooth 8101 of the sun gear 81, and will not be described in detail. Similarly, the size and shape of the teeth of the internal gear ring are also the same as those of the tooth 8101 of the sun gear 81, and the sizes and shapes of the teeth of other sun gears and planet gears are also the same as those of the tooth 8101 of the sun gear 81.

[0049] After the present utility model trims the tooth surface, the smoothness of the tooth surface 8105 is improved, the contact area of the tooth surface 8105 is increased and the transition is smooth, the meshing degree is significantly improved, the wear between gears during the working process is reduced, the noise and vibration are correspondingly reduced, and the NVH is significantly improved.

[0050] The drive device 100 is particularly suitable for vacuum cleaners.

[0051] The above-described embodiments merely represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A planetary gearbox, characterized in that: The planetary gearbox (80) includes a sun gear (81), a plurality of planet gears (82) surrounding the sun gear (81), an internal gear ring (83) surrounding the plurality of planet gears (82), and a gear carrier (85) for mounting the plurality of planet gears (82); The teeth (8101) of the sun gear (81) include a tooth tip (8103) and two tooth surfaces (8105), and the two tooth surfaces (8105) are respectively located on both sides of the tooth tip (8103); the tooth surface (8105) is trimmed near the tooth tip (8103) to form an outer arc surface; The teeth (8201) of the planet gear (82) and the size and shape of the teeth of the internal gear ring (83) are the same as those of the teeth (8101) of the sun gear (81).

2. The planetary gearbox according to claim 1, characterized in that The included angle (A2) formed by the tangents of the two tooth surfaces (8105) near the tooth tip (8103) is 45 to 75 degrees.

3. The planetary gearbox according to claim 1, characterized in that, The included angle (A2) formed by the tangents of the two tooth surfaces (8105) near the tooth tip (8103) is 55 to 65 degrees.

4. The planetary gearbox according to claim 1, wherein The outer arc surface (8105b) accounts for 50% to 90% of the surface area of the tooth surface (8105).

5. The planetary gearbox according to claim 1, wherein The outer arc surface (8105b) accounts for 70% to 85% of the surface area of the tooth surface (8105).

6. The planetary gearbox according to claim 1, characterized in that, Along the direction away from the tooth tip (8103), the included angle formed by the tangents of the two tooth surfaces (8105) at symmetric positions gradually increases, the maximum value of the included angle is 45 to 75 degrees, and the minimum value is 10 to 25 degrees.

7. The planetary gearbox according to claim 1, characterized in that, Along the direction away from the tooth tip (8103), the included angle formed by the tangents of the two tooth surfaces (8105) at symmetric positions gradually increases, the maximum value of the included angle is 55 to 65 degrees, and the minimum value is 12 to 20 degrees.

8. The planetary gearbox according to claim 1, characterized in that, The planetary gearbox includes two-stage reduction, and each stage of reduction includes a corresponding sun gear, a plurality of planet gears, and a gear carrier for mounting the plurality of planet gears; the sun gear of the second-stage reduction is driven by the gear carrier of the first-stage reduction; the planet gears of the two-stage reduction are meshed with the same internal gear ring.

9. A driving device, including a motor (30), characterized in that: It further includes the planetary gearbox (80) according to any one of claims 1 to 8, The driving device includes a cylindrical housing (10), the motor (30) is installed in the housing (10), and the rotating shaft (51) of the motor (30) extends from the front end of the motor (30); the planetary gearbox (80) is installed in the housing (10), the planetary gearbox (80) is located at the front end of the motor (30), and is positioned and aligned with the motor (30) under the constraint of the housing (10) to receive the output of the rotating shaft (51).

10. The driving device according to claim 9, characterized in that: The driving device includes a plurality of first radial connecting members (11), a plurality of second radial connecting members (12), a front end cover (21) and a rear end cover (31) at least partially received in the housing (10). The plurality of first radial connecting members (11) pass through the housing (10) and are fixedly connected to the rear end cover (31), and the plurality of second radial connecting members (12) pass through the housing (10) and are fixedly connected to the front end cover (21). The planetary gearbox (80) and the motor (30) are respectively limited by the front end cover (21) and the rear end cover (31) and fixedly received in the housing (10).

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