Cylinder shaft hub motor

Abstract

The utility model discloses a cylinder shaft hub motor, which has the advantages that at least one side of a second connecting part of a key body connected between a planet carrier and a cylinder shaft is connected with an extension part which exceeds a first connecting part and extends along the circumferential direction of the cylinder shaft, and the extension part is propped against the cylinder shaft to limit the key body to move inwards along the radial direction of the cylinder shaft; the extending part enables the width of the second connecting part to be larger than the width of the first connecting part and the width of the key groove, a step or a resisting part is formed between the first connecting part and the second connecting part, and after the planet carrier is connected, the inner end of the extending part abuts against the outer side wall of the cylinder shaft beside the key groove for limiting. Deformation of the bottom of the key groove is effectively reduced or avoided, the barrel shaft is not prone to being damaged, the mechanical strength of the barrel shaft is prevented from being weakened, and influences on a barrel shaft rod in the barrel shaft are avoided; in addition, the second connecting part is widened, so that the planet carrier and the barrel shaft are firmly connected, the stability is good, and looseness of the planet carrier and abnormal sound generated by looseness are avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of drive motors, in particular to a cylindrical shaft hub motor. Background Art

[0002] An electric power-assisted bicycle is composed of an ordinary bicycle with a drive motor. The drive motor is powered by a battery installed on the frame, and the rotation of the drive motor drives the electric power-assisted bicycle forward. In order to improve the efficiency of electric energy utilization and reduce transmission losses, the drive motor is generally installed in the front or rear wheel hub, so it is also called a hub motor. As the core power component of an electric power-assisted bicycle, the stability, durability, lightness and service life of the hub motor are important indicators for measuring the quality of the hub motor.

[0003] Among them, the main shaft of the barrel shaft hub motor (also called barrel shaft hub motor, through-axle hub motor) adopts a barrel shaft, and the planetary reduction mechanism and the clutch are assembled in sequence along this through shaft. In the conventional structural design of the barrel shaft hub motor, in order to make the structure compact, the clutch is often integrated into the planetary reduction mechanism, that is, the planetary carrier used to support or install the planetary gear is also called the clutch bracket; the planetary carrier and the barrel shaft are fixedly connected, and the two are generally fixedly connected by a key connection. The firmness and stability of the connection between the planetary carrier and the barrel shaft directly affect the performance of the hub motor. At present, in order to facilitate the installation or disassembly of the hub motor with the frame, the barrel shaft of the hub motor is generally set to be hollow, and a barrel shaft rod (also called a quick-release rod) is inserted in the center hole of the barrel shaft, and the hub motor is quickly installed on the frame through the locking nuts threaded at both ends of the barrel shaft rod.

[0004] The above-mentioned cylindrical shaft hub motor with cylindrical shaft rod in the related art has the following deficiencies: the cylindrical shaft of the cylindrical shaft hub motor with cylindrical shaft rod is a hollow shaft, and its wall thickness is limited, so that the wall thickness between the bottom of the keyway on the cylindrical shaft and the inner wall of the center hole of the cylindrical shaft is relatively thin, and the key installed in the keyway of the cylindrical shaft is generally a rectangular key, part of the key is located in the keyway of the cylindrical shaft, and the other part is located in the keyway on the inner wall of the planetary carrier mounting hole of the planetary reduction mechanism. When the planetary carrier of the planetary reduction mechanism is installed and the strength or torque test is carried out, or after the hub motor is used for a long time, the planetary carrier applies torque to the cylindrical shaft through the key, which causes the bottom wall of the cylindrical shaft keyway to deform under the extrusion of the key, and even causes the bottom wall of the cylindrical shaft keyway to penetrate its center hole, which not only affects the cylindrical shaft rod in the center hole of the cylindrical shaft, but also weakens the mechanical strength of the cylindrical shaft, limiting the output torque of the hub motor; and it also causes the planetary carrier to loosen and produce abnormal noise. Utility Model Content

[0005] The technical problem to be solved by the present application is to overcome the defects of the above-mentioned related technologies and provide a cylindrical shaft hub motor which can make the planetary carrier of the planetary reduction mechanism firmly connected and stable, and can effectively avoid or reduce the deformation of the bottom of the cylindrical shaft keyway, so that the cylindrical shaft is not easily damaged.

[0006] The technical solution of the present application is to provide a cylindrical shaft hub motor with the following structure: it includes a cylindrical shaft and a planetary reduction mechanism, the planetary carrier of the planetary reduction mechanism is installed on the cylindrical shaft, a keyway is provided at a position on the cylindrical shaft for installing the planetary carrier, and a key body is connected in the keyway to keep the planetary carrier in a fixed position relative to the cylindrical shaft, the key body includes a first connecting portion inserted in the keyway and a second connecting portion at least partially inserted in the planetary carrier, at least one side of the second connecting portion is connected to an extension portion extending circumferentially of the cylindrical shaft beyond the first connecting portion, and the extension portion abuts against the cylindrical shaft.

[0007] Compared with the related technology, the cylindrical shaft hub motor of the present application has the following advantages: the cylindrical shaft hub is connected to the key body between the planetary carrier and the cylindrical shaft of the planetary reduction mechanism of the motor, and at least one side of its second connection part is connected to an extension part that exceeds the first connection part and extends outward along the circumference of the cylindrical shaft, and the extension part abuts against the cylindrical shaft to limit the radial inward displacement of the key body along the cylindrical shaft. The extension portion widens the width of the second connecting portion of the key body, making the width of the second connecting portion greater than the width of the first connecting portion and the keyway, so that a step or abutment portion is formed between the second connecting portion and the first connecting portion, that is, after the planetary carrier is connected, one end of the extension portion of the key body close to the first connecting portion abuts against the outer wall of the cylinder shaft outside the keyway to limit the position. In this way, after the planetary carrier is installed, the extension portion of the key body abuts against the outer wall of the cylinder shaft, and the cylinder shaft at the abutting portion has a large thickness and high mechanical strength, thereby reducing or eliminating the pressure between the first connecting portion of the key body and the bottom of the keyway, effectively reducing or avoiding deformation of the bottom of the cylinder shaft keyway, avoiding weakening of the mechanical strength of the cylinder shaft, making the cylinder shaft less prone to damage, improving the output torque of the cylinder shaft hub motor, and avoiding affecting the cylinder shaft rod in the cylinder shaft; in addition, the width of the second connecting portion of the key body is widened, so that the connection between the planetary carrier and the cylinder shaft of the planetary reduction mechanism is firm and stable, avoiding loosening of the planetary carrier and abnormal noise caused by loosening.

[0008] Preferably, both sides of the second connection part are connected with extension parts, and the two extension parts respectively abut against the outer side walls of the cylinder shaft on both sides of the keyway. The abutment on both sides of the keyway can better limit the radial inward displacement of the key body along the cylinder shaft, and the pressure at the bottom of the keyway is smaller or eliminated due to the squeezing force of the first connection part.

[0009] Preferably, the extension portion and the second connection portion are integrally formed. The key body of the integral structure has high mechanical strength and can also avoid an increase in the number of parts and corresponding installation processes.

[0010] As an improvement, the extension portion forms a fitting portion at one end thereof close to the first connection portion, which fits the surface of the cylindrical shaft; the fitting portion is configured so that when the planet carrier has a tendency to rotate circumferentially relative to the cylindrical shaft, the fitting portion and the cylindrical shaft surface are tightly pressed against each other to increase the contact area, expand the force-bearing surface, and reduce the deformation of the groove walls on both sides of the keyway.

[0011] In some embodiments, a locking nut is threadedly connected to the first end of the cylindrical shaft rod, and a limiting stud is connected to the second end of the cylindrical shaft rod, and the locking nut and the limiting stud are used to connect the two ends of the cylindrical shaft to the frame. The limiting stud can accurately position and facilitate the installation of the cylindrical shaft hub motor.

[0012] In some embodiments, the limiting column head is connected with a handle extending outwardly along the cylindrical shaft rod, and the handle can be rotated for disassembly and assembly, thereby reducing the selection and adaptation of disassembly and assembly tools and improving disassembly and assembly efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic cross-sectional structure diagram of a cylindrical shaft hub motor according to some embodiments of the present application.

[0014] Figure 2 is a cross-sectional view of a key body installation of a cylindrical axle hub motor according to some embodiments of the present application.

[0015] Figure 3 It is a schematic diagram of the structure of a cylindrical shaft hub motor according to some embodiments of the present application.

[0016] Description of reference numerals:

[0017] 1. Hub shell, 100. Base, 101. End cover, 2. Cylindrical shaft, 200. Center hole, 201. Keyway, 3. Cylindrical shaft rod, 300. Locking nut, 301. Limiting column head, 302. Handle, 4. Stator winding, 400. Rotor, 5. Planetary reduction mechanism, 500. Sun gear, 501. Planet carrier, 502. Planetary gear, 503. Gear ring, 6. Key body, 600. First connecting part, 601. Second connecting part, 602. Extension part, 603. Fitting part, 7. First bearing, 700. Second bearing. DETAILED DESCRIPTION

[0018] First, those skilled in the art should understand that these implementations are only used to explain the technical principles of the embodiments of the present application, and are not intended to limit the protection scope of the embodiments of the present application. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0019] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0020] In the embodiments of the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0021] The utility model is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] like Figures 1 to 3 As shown; the embodiment of the present application discloses a cylindrical hub motor, whose structure includes a coaxially arranged hub shell 1, a cylindrical shaft 2, a stator winding 4, a rotor 400 and a planetary reduction mechanism 5, the cylindrical shaft 2 is a hollow structure, has a center hole 200, and a cylindrical shaft rod 3 is passed through the center hole 200; in this embodiment, the planetary reduction mechanism 5 is also called a planetary gear reduction mechanism, or a planetary gear transmission mechanism, etc., the planetary reduction mechanism 5 includes a planetary carrier 501, a sun gear 500 and a plurality of planetary gears installed on the planetary carrier 5 01, the planetary gear 502 on the planetary carrier 501 is installed on the barrel shaft 2, the sun gear 500 is connected to the rotor 400, and the sun gear 500 is rotatably connected to the barrel shaft 2; in this embodiment, the planetary gear 502 is a primary transmission gear, the planetary gear 502 is rotatably connected to the planetary carrier 501, and the rotation axis of each planetary gear 502 coincides with the axis of the barrel shaft 2, the inner side of the planetary gear 502 is externally meshed with the sun gear 500, and the outer side of the planetary gear 502 is internally meshed with the wheel hub shell 1. After the stator winding 4 is energized, the rotor 400 drives the sun gear 500 to rotate, and the sun gear 500 drives the wheel hub shell 1 to rotate at a reduced speed through the planetary gear 502.

[0023] In this embodiment, if Figure 1As shown, the hub shell 1 is connected to the annular base 100, and the base 100 is rotatably connected to the cylindrical shaft 2 through the first bearing 7, and a gear ring 503 is provided in the hub shell 1 along the circumferential direction; each planetary gear 502 of the planetary reduction mechanism 5 is meshed with the gear ring 503 for transmission; an end cover 101 is connected to one end of the hub shell 1, and the end cover 101 is rotatably connected to the cylindrical shaft 2 through the second bearing 700. The hub shell 1, the end cover 101 and the base 100 together enclose a space for installing the stator winding 4, the rotor 400 and the planetary reduction mechanism 5, and the sun gear 500, the planetary gear 502 and the gear ring 503 of the planetary reduction mechanism 5 constitute a two-stage transmission to realize the rotation of the hub shell 1, and its overall structure is compact and small in size.

[0024] In this embodiment, if Figure 1 and Figure 2 As shown, the connection structure between the planet carrier 501 and the cylindrical shaft 2 is that a keyway 201 is provided at the position of the cylindrical shaft 2 where the planet carrier 501 is installed, and the keyway 201 extends along the axial direction of the cylindrical shaft 2 and is set as a square keyway 201; a key body 6 is connected in the keyway 201 to keep the planet carrier 501 fixed relative to the cylindrical shaft 2, and the key body 6 includes a first connection part 600 inserted or accommodated in the keyway 201 and a second connection part 601 at least partially inserted or accommodated in the planet carrier 501, and at least one side of the second connection part 601 is connected to an extension part 602 extending beyond the first connection part 600 along the circumferential direction of the cylindrical shaft 2, and the extension part 602 abuts against the cylindrical shaft 2 to limit the radial inward displacement of the key body 6 along the cylindrical shaft 2. Specifically in this embodiment, the planet carrier 501 has a mounting hole sleeved on the cylindrical shaft 2, and a hole groove (not shown in the figure) is provided on the inner wall of the mounting hole to at least partially accommodate the second connection part 601.

[0025] It is not difficult to understand that when the above-mentioned extension part 602 is connected to one side of the second connecting part 601, the extension setting direction of the extension part 602 is consistent with the force direction of the planetary carrier 501. When the planetary carrier 501 drives the key body 6 to have a rotation tendency, the extension part 602 can be against the outer wall of the cylinder shaft 2.

[0026] In this embodiment, if Figure 1 and Figure 2As shown, the planet carrier 501 of the cylindrical shaft hub motor planetary reduction mechanism 5 is connected to the cylindrical shaft 2 through the key body 6, and at least one side of the second connection part 601 of the key body 6 is connected to an extension part 602 extending outward along the circumferential direction of the cylindrical shaft 2, and the extension part 602 abuts against the cylindrical shaft 2 to limit the radial inward displacement of the key body 6 along the cylindrical shaft 2. The extension part 602 widens the width of the second connection part 601 of the key body 6, so that the width dimension of the second connection part 601 is larger than the width dimension of the first connection part 600 and the key slot 201, so that a step or abutment is formed between the second connection part 601 and the first connection part 600, that is, after the planet carrier 501 is connected, the end of the extension part 602 of the key body 6 close to the first connection part 600 abuts against the outer wall of the cylindrical shaft 2 outside the key slot 201 to limit the position, so that after the planet carrier 501 is installed, due to the extension part 602 of the key body 6 and the cylindrical shaft 2 The outer walls abut against each other, thereby reducing or eliminating the pressure between the first connecting portion 600 of the key body 6 and the bottom of the keyway 201, effectively avoiding or reducing deformation of the bottom of the keyway 201 of the cylindrical shaft 2, making the cylindrical shaft 2 less susceptible to damage, avoiding the mechanical strength of the cylindrical shaft 2 from being weakened, and avoiding affecting the cylindrical shaft rod 3 inside the cylindrical shaft 2; in addition, the width of the second connecting portion 601 of the key body 6 is widened, so that the planetary carrier 501 of the planetary reduction mechanism 5 and the cylindrical shaft 2 are firmly connected and stable, avoiding loosening of the planetary carrier 501 and abnormal noise caused by loosening.

[0027] In some embodiments, both sides of the second connection portion 601 are connected with extension portions 602 extending outward along the circumferential direction of the cylindrical shaft 2, and the two extension portions 602 respectively abut against the outer side walls of the cylindrical shaft 2 on both sides of the keyway 201. This not only makes the connection between the planet carrier 501 and the cylindrical shaft 2 more secure, but also, after the planet carrier 501 is installed, because the extension portions 602 on both sides of the key body 6 abut against the outer side walls of the cylindrical shaft 2, the pressure between the first connection portion 600 of the key body 6 and the bottom of the keyway 201 is further reduced or eliminated, and the deformation of the bottom of the keyway 201 of the cylindrical shaft 2 is more effectively avoided or reduced.

[0028] In the above embodiment, if Figure 2 As shown, the extension portion 602 and the second connecting portion 601 are an integrally formed structure; this makes the mechanical strength of the key body 6 higher; of course, in other embodiments, the extension portion 602 can also be an extension portion 602 connected to the second connecting portion 601, for example, the extension portion 602 is formed by assembly or welding.

[0029] It can be understood that in this embodiment, the position of the planetary carrier 501 and the cylindrical shaft 2 remains fixed under the keying action of the key body 6; when the hub motor outputs torque, due to the transmission relationship of the planetary reduction mechanism 5, the planetary carrier 501 will be subjected to a circumferential reaction torque, so that the planetary carrier 501 has a circumferential rotation tendency relative to the cylindrical shaft 2. At this time, the planetary carrier 501 applies torque to the second connecting portion 601 of the key body 6, and the first connecting portion 600 of the key body 6 will have a rotation tendency, so that the bottom of the first connecting portion 600 of the key body 6 applies pressure or shear force to the bottom wall of the key slot 201, and this force can easily deform the bottom wall of the key slot 201 or even penetrate it.

[0030] In some embodiments, see again Figure 2 As shown, in order to overcome the above defects, the extension part 602 forms a fitting surface 603 that matches and fits with the surface of the cylindrical shaft 2 at one end thereof close to the first connecting part 600; the fitting surface 603 is configured so that when the planetary carrier 501 has a tendency to rotate circumferentially relative to the cylindrical shaft 2, the fitting surface 603 and the surface of the cylindrical shaft 2 are tightly pressed against each other to limit the position. That is, when the planetary carrier 501 is subjected to a force and has a tendency to rotate forward or reverse along the circumference of the cylindrical shaft 2, the fitting surfaces 603 of the extension parts 602 on both sides of the second connecting part 601 can be pressed against the outer wall of the cylindrical shaft 2 to limit the key body 6 from rotating and squeezing the bottom of the key slot 201. In other words, the fitting surface 603 of the extension part 602 acts on the surface of the cylindrical shaft 2, which can better avoid or weaken the pressure of the first connecting part 600 of the key body 6 on the bottom of the key slot 201. Here, the fitting surface 603 should not be understood as being limited to an arc-shaped curved surface. The fitting surface 603 may also be a plane, and the surfaces of the cylinder shaft 2 on both sides of the corresponding keyway 201 are provided with matching abutment planes.

[0031] In some embodiments, Figure 1 As shown, the first end of the cylindrical shaft rod 3 is threadedly connected with a locking nut 300, and the second end of the cylindrical shaft rod 3 is connected to a limiting stud 301. The locking nut 300 and the limiting stud 301 are used to connect the two ends of the cylindrical shaft 2 to the frame. In order to facilitate the rotation of the cylindrical shaft rod 3 or the connection to the frame, the end surface of the limiting stud 301 is provided with an operation hole for inserting a manual tool such as a screwdriver. During installation, the locking nut 300 of the cylindrical shaft rod 3 is loosened to allow the two ends of the cylindrical shaft 2 to be clamped into the front fork or rear fork of the frame, and then the locking nut 300 is locked to complete the installation of the hub motor.

[0032] In another embodiment, if Figure 3 As shown, in order to facilitate the rotation of the cylindrical shaft rod 3, a handle 302 extending laterally outward along the cylindrical shaft rod 3 is connected to the limiting column head 301, and the cylindrical shaft rod 3 can be driven to rotate by turning the handle 302, thereby realizing the installation or removal of the hub motor. Other technical solutions of this embodiment are the same as those of the previous embodiment, and are not described in detail in this embodiment.

[0033] In the description of the embodiments of the present application, it should be noted that in the description of the present application, terms such as "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is only for the convenience of description, and does not indicate or imply that the device or component must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present application.

[0034] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "in the present embodiment", "specific example", or "some examples" etc. means that the specific features, mechanisms, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, mechanisms, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

Claims

1. A cylindrical shaft hub motor, comprising a cylindrical shaft and a planetary reduction mechanism, wherein a planet carrier of the planetary reduction mechanism is mounted on the cylindrical shaft; a keyway is provided at a position on the cylindrical shaft where the planet carrier is mounted, and a key body is installed in the keyway to keep the planet carrier in a fixed position relative to the cylindrical shaft, characterized in that: The key body includes a first connection part inserted in the keyway and a second connection part at least partially inserted in the planet carrier, at least one side of the second connection part is connected to an extension part extending beyond the first connection part along the circumferential direction of the barrel shaft, and the extension part abuts against the barrel shaft.

2. The cylindrical shaft hub motor according to claim 1, characterized in that: Both sides of the second connecting portion are connected with extension portions, and the two extension portions respectively abut against the outer side walls of the cylindrical shaft at both sides of the keyway.

3. The cylindrical shaft hub motor according to claim 1 or 2, characterized in that: The extending portion and the second connecting portion are an integrally formed structure.

4. The cylindrical shaft hub motor according to claim 1 or 2, characterized in that: The extension portion forms a fitting surface at its inner end close to the first connecting portion, which matches and fits with the surface of the barrel shaft; the fitting surface is configured so that when the planet carrier has a circumferential rotation tendency relative to the barrel shaft, the fitting surface and the barrel shaft surface are tightly pressed and limited.

5. The cylindrical shaft hub motor according to claim 1, characterized in that: The first end of the cylindrical shaft rod is threadedly connected with a locking nut, and the second end of the cylindrical shaft rod is connected to a limiting column head. The locking nut and the limiting column head are used to connect the two ends of the cylindrical shaft to the frame.

6. The cylindrical shaft hub motor according to claim 5, characterized in that: The limiting column head is connected with a handle extending outwardly along the cylindrical shaft rod in a transverse direction.

Images