Sun gear and motor rotor assembly using same

Abstract

The utility model discloses a sun gear and a motor rotor assembly using the sun gear. The sun gear comprises a bearing matching part, a meshing tooth part, an assembling tooth part and a guiding tooth part which are integrally and coaxially formed, wherein a plurality of spline racks are uniformly arranged on the assembling tooth part and the guiding tooth part in the circumferential direction; a plurality of gear racks are uniformly arranged on the meshing tooth parts in the circumferential direction; spline racks of the assembly tooth part and the guide tooth part and gear racks of the meshing tooth part are continuously arranged in the axial direction; and the addendum circle of the spline rack of the guide tooth part is smaller than the addendum circle of the spline rack of the assembly tooth part. According to the utility model, the assembly precision requirement can be ensured on the basis of reducing the assembly difficulty.

Description

Technical Field

[0001] The utility model relates to the technical field of motors, in particular to a sun wheel and a motor rotor assembly using the sun wheel. Background Art

[0002] The joint drive modules of automation equipment mostly use a reduction planetary gear system driven by a permanent magnet brushless outer rotor motor. In order to achieve large torque output and light weight, the product must have high reliability and compact size.

[0003] In order to ensure a compact and lightweight structure, the rotor frame is generally made of die-cast aluminum alloy or magnesium alloy, which can meet the complex structural design of the rotor frame and good machining requirements. The sun gear is generally manufactured by machining or powder metallurgy. For high-power and low-speed conditions, the sun gear uses structural steel for tooth processing and heat treatment. For light loads or conditions with higher cost requirements, the sun gear is mostly processed by powder metallurgy and supplemented by simple machining processes. Regardless of the sun gear manufacturing process used, due to the large differences in the elastic modulus and thermal expansion coefficients of the two assembly materials, the reliability of the rotor assembly using traditional interference fit cannot be well guaranteed under high speed, long-term load and high temperature conditions, and failures such as sun gear falling off and slipping are prone to occur.

[0004] To address this problem, some products use spline connection to improve the connection reliability between the sun gear and the rotor frame. For example, a through-type sun gear disclosed in announcement number CN213206489U has a plurality of spline racks on the extension of one end of the body, and a plurality of gear racks on the extension of the other end of the body. The spline rack and the gear rack are an integrated structure, which makes the gear and the spline form an integrated structure, which solves the problem of looseness between the traditional spline and the gear, thereby ensuring that the spline and the gear can rotate synchronously.

[0005] For the above-mentioned sun gear, actual research has found that it has the following defects: during the spline press-fit connection process, the rotor frame material is prone to plastic deformation, the sun gear assembly size cannot be guaranteed, and even the rotor frame cracks. This places high demands on the spline press-fit process, which requires matching the design of multiple factors such as spline tooth shape, interference fit, and press-fit speed.

[0006] Therefore, from the perspective of simplifying the press-fitting process, the structure of the sun gear needs to be further optimized. Utility Model Content

[0007] The first purpose of the utility model is to provide a sun gear to solve the technical problem of improving its carrying capacity.

[0008] The second object of the utility model is to provide a motor rotor assembly to solve the technical problem of simplifying the press-fitting process of the rotor frame and the sun gear.

[0009] The sun gear of the utility model is realized as follows:

[0010] A sun gear comprises: a bearing matching portion, a meshing tooth portion, an assembly tooth portion and a guide tooth portion which are coaxially formed in one piece; wherein

[0011] A plurality of spline racks are evenly arranged along the circumferential direction on the assembly tooth portion and the guide tooth portion; a plurality of gear racks are evenly arranged along the circumferential direction on the meshing tooth portion;

[0012] The spline racks of the assembly tooth portion and the guide tooth portion and the gear racks of the meshing tooth portion are arranged continuously along the axial direction; and

[0013] The tooth addendum circle of the spline rack of the guide tooth portion is smaller than the tooth addendum circle of the spline rack of the assembly tooth portion.

[0014] In an optional implementation of the present invention, the tooth roots of the spline rack of the guide tooth portion, the spline rack of the assembly tooth portion, and the gear rack of the meshing tooth portion are all integrally connected.

[0015] In an optional implementation of the present invention, rounded or beveled transitions are used between the meshing tooth portion and the assembly tooth portion, and between the assembly tooth portion and the guide tooth portion.

[0016] The motor rotor assembly of the utility model is realized as follows:

[0017] A motor rotor assembly comprises: the sun gear, a rotor frame having an interference fit with the assembly teeth of the sun gear, and a yoke assembly connected to the rotor frame;

[0018] The yoke assembly comprises an annular yoke and a plurality of magnetic steels arranged along a circumferential direction on one side of an inner ring wall of the annular yoke.

[0019] In an optional implementation of the present invention, the rotor frame includes a disc-shaped body and a columnar connecting portion integrally provided on the central axis of the disc-shaped body; wherein

[0020] A central shaft hole is formed through the columnar connecting portion for interference fit with the assembly tooth portion of the sun gear.

[0021] In an optional implementation of the utility model, the disc-shaped body is provided with an annular stopper for matching with the annular magnetic yoke along the circumferential direction;

[0022] The disc-shaped body is also provided with a limiting toothed disc for mounting a plurality of magnetic steels; the limiting toothed disc is formed with a plurality of slots suitable for one-to-one mounting of the magnetic steels at intervals.

[0023] In an optional implementation of the present invention, the central axis hole includes an assembly hole, a guide hole and a process hole which are axially penetrated in sequence; wherein

[0024] The assembly teeth match the assembly holes, and the guide teeth match the guide holes; and

[0025] The inner diameter of the assembly hole is larger than the inner diameter of the guide hole, and the inner diameter of the process hole is smaller than the inner diameter of the guide hole;

[0026] The tooth top circle size of the assembly tooth portion is larger than the inner diameter of the assembly hole, and there is a transition fit between the guide tooth portion and the guide hole.

[0027] In an optional implementation of the present invention, the axial length of the assembly hole is 2 to 3 mm longer than the axial length of the assembly tooth portion.

[0028] In an optional implementation of the utility model, a diameter reducing portion is provided at the end portion where the assembly hole is connected to the guide hole;

[0029] The inner diameter of the diameter-reducing portion is greater than the inner diameter of the assembly hole.

[0030] In an optional implementation of the present invention, an annular receiving groove is provided between the assembly tooth portion and the guide tooth portion and is recessed relative to the guide tooth portion.

[0031] By adopting the above technical scheme, the utility model has the following beneficial effects: the sun gear of the utility model and the motor rotor assembly using the sun gear enter the guide hole through the guide tooth portion on the sun gear, thereby ensuring the initial concentricity and verticality of the sun gear and the rotor frame. At this moment, the assembly tooth portion has no contact with the assembly hole. Next, when the sun gear is pressed in, the assembly tooth portion and the assembly hole are interference connected. Due to the guidance of the guide tooth portion, the assembly size can be well guaranteed, that is, the assembly accuracy requirements can be guaranteed while reducing the difficulty of assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic diagram of the exploded structure of the motor rotor assembly of an embodiment of the present application;

[0033] Figure 2 is a schematic structural diagram of a sun gear of a motor rotor assembly according to an embodiment of the present application;

[0034] Figure 3 is a schematic diagram of a sun of a motor rotor assembly according to an embodiment of the present application in another implementation situation;

[0035] Figure 4 is a schematic diagram of a central axis hole of a rotor frame of a motor rotor assembly in an embodiment of the present application in an implementation situation;

[0036] Figure 5is a schematic diagram of a central axis hole of a rotor frame of a motor rotor assembly and a sun gear in another matching condition in an embodiment of the present application;

[0037] Figure 6 It is a schematic diagram of the central axis hole of the rotor frame of the motor rotor assembly according to an embodiment of the present application in another implementation situation.

[0038] In the figure: bearing mating part 1, meshing tooth part 2, assembly tooth part 3, guide tooth part 4, spline rack 5, gear rack 6, tooth groove 7, annular yoke 8, magnetic steel 9, disc-shaped body 101, annular stop 102, slot 103, limit gear disc 104, assembly hole 105, guide hole 106, process hole 107, diameter reducing part 108, extension section 109, annular receiving groove 200. DETAILED DESCRIPTION

[0039] In order to make the content of the utility model more clearly understood, the utility model is further described in detail below based on specific embodiments and in conjunction with the accompanying drawings.

[0040] Embodiment 1:

[0041] See also Figures 1 to 6 As shown, this embodiment provides a sun gear, including: an integrally coaxially formed bearing mating portion 1, a meshing tooth portion 2, an assembly tooth portion 3 and a guide tooth portion 4; wherein a plurality of spline racks 5 are evenly arranged along the circumferential direction on the assembly tooth portion 3 and the guide tooth portion 4; and a plurality of gear racks 6 are evenly arranged along the circumferential direction on the meshing tooth portion 2.

[0042] Furthermore, the spline racks 5 of the assembly tooth portion 3 and the guide tooth portion 4 and the gear rack 6 of the meshing tooth portion 2 are arranged continuously along the axial direction; and the addendum circle of the spline rack 5 of the guide tooth portion 4 is smaller than the addendum circle of the spline rack 5 of the assembly tooth portion 3. It is necessary to explain that the sun gear in this embodiment can be manufactured by machining or powder metallurgy, and the guide tooth portion 4 and the assembly tooth portion 3 are subsequently realized by machining the outer circle.

[0043] Based on the above situation, in a specific optional implementation, the tooth top circle of the gear rack 6 of the meshing tooth portion 2 is larger than the tooth top circle of the spline rack 5 of the assembly tooth portion 3, thereby improving the meshing strength of the meshing tooth portion 2.

[0044] On the basis of the above structure, further speaking, the tooth roots of the spline rack 5 of the guide tooth portion 4, the spline rack 5 of the assembly tooth portion 3 and the gear rack 6 of the meshing tooth portion 2 are all integrally connected, which can well ensure the service strength of the tooth roots of the guide tooth portion 4, the assembly tooth portion 3 and the gear rack 6.

[0045] In addition, it should be noted that rounded corners or beveled corners are used for transition between the meshing tooth portion 2 and the assembly tooth portion 3 , and between the assembly tooth portion 3 and the guide tooth portion 4 .

[0046] In an optional implementation, from the perspective of ease of processing, in this embodiment, the widths of the tooth grooves 7 formed between the spline racks 5 of the guide tooth portion 4, the tooth grooves 7 formed between the spline racks 5 of the assembly tooth portion 3, and the tooth grooves 7 formed between the gear racks 6 of the meshing tooth portion 2 are all the same.

[0047] In summary, for the sun gear of this embodiment, the guide tooth portion 4, the assembly tooth portion 3, and the meshing tooth portion 2 are an integral tooth shape, the tooth root portions of the assembly tooth portion 3 and the meshing tooth portion 2 are connected, the meshing gear has good strength, and has the advantage of high load reliability.

[0048] Embodiment 2:

[0049] Based on the sun gear of Example 1, this embodiment provides a motor rotor assembly, comprising: the sun gear of Example 1, a rotor frame having an interference fit with the assembly tooth portion 3 of the sun gear, and a yoke assembly connected to the rotor frame. The yoke assembly comprises an annular yoke 8 and a plurality of magnetic steels 9 arranged along the circumferential direction on one side of the inner ring wall of the annular yoke 8.

[0050] It should be noted that the rotor frame used in this embodiment includes a disc-shaped body 101 and a columnar connecting portion integrally provided on the central axis of the disc-shaped body 101; wherein a central axis hole for interference fit with the assembly tooth portion 3 of the sun gear is formed through the columnar connecting portion.

[0051] Based on the above situation, to further explain, the disc-shaped body 101 is provided with an annular stopper 102 for matching with the annular magnetic yoke 8 along the circumferential direction; the disc-shaped body 101 is also provided with a limiting toothed disc 104 for mounting multiple magnetic steels 9; the limiting toothed disc 104 is formed with multiple slots 103 suitable for one-to-one mounting of magnetic steels 9. In industrial production, anaerobic glue is generally used to bond the magnetic steel 9 and the annular magnetic yoke 8 together.

[0052] Furthermore, the central axis hole in this embodiment includes an assembly hole 105, a guide hole 106 and a process hole 107 which are axially penetrated in sequence; wherein the assembly tooth portion 3 and the assembly hole 105 are matched, and the guide tooth portion 4 and the guide hole 106 are matched; and the inner diameter of the assembly hole 105 is larger than the inner diameter of the guide hole 106, and the inner diameter of the process hole 107 is smaller than the inner diameter of the guide hole 106. The tooth top circle size of the assembly tooth portion 3 is larger than the inner diameter of the assembly hole 105, and the guide tooth portion 4 and the guide hole 106 are transitionally matched.

[0053] It should be noted that, in the actual process of press-fitting the sun gear and the center axis hole of the rotor frame, in some cases, due to the large assembly interference of the spline rack 5 of the assembly tooth portion 3 or the excessively fast press-fitting speed, the metal hardness of the rotor frame is relatively low. During the process of pressing the spline rack 5 of the assembly tooth portion 3 into the assembly hole 105, some metal debris caused by the scraping of the spline will be generated in the assembly hole 105. In order to prevent the debris from affecting the assembly size and the debris from scattering and polluting, in an optional implementation, the axial length of the assembly hole 105 of the rotor frame can be designed to be 2 to 3 mm longer than the axial length of the assembly tooth portion 3 (that is, equivalent to extending the assembly hole 105, that is, designing an extension section 109 in the assembly hole 105). In this way, after the sun gear is press-fitted into place, some debris can be stored in the gap formed between the end of the assembly tooth portion 3 facing the guide tooth portion 4 and the end of the assembly hole 105 connecting the guide hole 106, thereby preventing the scattered and excessive debris from causing additional obstruction to the sun gear and causing the assembly size to deteriorate.

[0054] Also out of consideration for the problem of metal debris caused by partial spline scratching in the assembly hole 105 , in another optional implementation, a reducing portion 108 is provided at the end of the assembly hole 105 connected to the guide hole 106 ; the inner diameter of the reducing portion 108 is larger than the inner diameter of the assembly hole 105 .

[0055] In addition, based on the above two different implementations, this implementation can also be processed as follows: an annular receiving groove 200 is provided between the assembly tooth portion 3 and the guide tooth portion 4, which is concave relative to the guide tooth portion 4. The annular receiving groove 200 here is used to receive metal debris scraped by part of the spline generated in the assembly hole 105. It should be noted that the annular receiving groove 200, the diameter reducing portion 108 and the situation of extending the assembly hole 105 here can exist at the same time, or only one or any two structures can be used, and this embodiment does not make an absolute limitation on this.

[0056] In summary, for the motor rotor assembly of this embodiment, the sun gear and the rotor frame are fixedly assembled together. As the power output part, the connection reliability of the sun gear and the rotor frame and the assembly size (the verticality and concentricity of the sun gear relative to the rotor frame after assembly) have a decisive influence on the efficiency, life and vibration noise of the planetary gear transmission. In this embodiment, the guide tooth portion 4 on the sun gear enters the guide hole 106 to ensure the initial concentricity and verticality of the sun gear and the rotor frame. At this moment, the assembly tooth portion 3 has no contact with the assembly hole 105. When the sun gear is pressed in, the assembly tooth portion 3 is interference-connected with the assembly hole 105. Due to the guidance of the guide tooth portion 4, the assembly size can be well guaranteed, that is, the assembly accuracy requirements can be guaranteed on the basis of reducing the difficulty of assembly.

[0057] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0058] In the description of the present invention, it is necessary to understand that the terms indicating orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0059] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like 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 a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0060] In the description of the present utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the utility model product is usually placed when in use, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0061] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0062] In the present utility model, unless otherwise clearly specified and limited, the first feature being above or below the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through another feature between them. Moreover, the first feature being above, above, and above the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being below, below, and below the second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

Claims

1. A sun gear, characterized in that: include: The bearing matching part, meshing tooth part, assembly tooth part and guide tooth part are coaxially formed in one piece; in A plurality of spline racks are evenly arranged along the circumferential direction on the assembly tooth portion and the guide tooth portion; a plurality of gear racks are evenly arranged along the circumferential direction on the meshing tooth portion; The spline racks of the assembly tooth portion and the guide tooth portion and the gear racks of the meshing tooth portion are arranged continuously along the axial direction; and The tooth addendum circle of the spline rack of the guide tooth portion is smaller than the tooth addendum circle of the spline rack of the assembly tooth portion.

2. The sun gear according to claim 1, characterized in that: The tooth roots of the spline rack of the guide tooth portion, the spline rack of the assembly tooth portion and the gear rack of the meshing tooth portion are all connected in one piece.

3. The sun gear according to claim 1 or 2, characterized in that: Rounded corners or beveled corners are used for transition between the meshing tooth portion and the assembly tooth portion, and between the assembly tooth portion and the guide tooth portion.

4. A motor rotor assembly, characterized in that: include: The sun gear according to any one of claims 1 to 3, a rotor frame having an interference fit with the assembly teeth of the sun gear, and a yoke assembly connected to the rotor frame; The yoke assembly comprises an annular yoke and a plurality of magnetic steels arranged along a circumferential direction on one side of an inner ring wall of the annular yoke.

5. The motor rotor assembly according to claim 4, characterized in that: The rotor frame includes a disc-shaped body and a columnar connecting portion integrally arranged on the central axis of the disc-shaped body; wherein A central shaft hole is formed through the columnar connecting portion for interference fit with the assembly tooth portion of the sun gear.

6. The motor rotor assembly according to claim 5, characterized in that: The disc-shaped body is provided with an annular stopper along the circumferential direction for matching with the annular magnetic yoke; The disc-shaped body is also provided with a limiting toothed disc for mounting a plurality of magnetic steels; the limiting toothed disc is formed with a plurality of slots suitable for one-to-one mounting of the magnetic steels at intervals.

7. The motor rotor assembly according to claim 5 or 6, characterized in that: The central axis hole includes an assembly hole, a guide hole and a process hole which are axially penetrated in sequence; wherein The assembly teeth match the assembly holes, and the guide teeth match the guide holes; and The inner diameter of the assembly hole is larger than the inner diameter of the guide hole, and the inner diameter of the process hole is smaller than the inner diameter of the guide hole; The tooth top circle size of the assembly tooth portion is larger than the inner diameter of the assembly hole, and there is a transition fit between the guide tooth portion and the guide hole.

8. The motor rotor assembly according to claim 7, characterized in that: The axial length of the assembly hole is 2 to 3 mm longer than the axial length of the assembly tooth portion.

9. The motor rotor assembly according to claim 7, characterized in that: The end portion of the assembly hole connected to the guide hole is provided with a diameter reducing portion; The inner diameter of the diameter-reducing portion is greater than the inner diameter of the assembly hole.

10. The motor rotor assembly according to any one of claims 4 to 6, characterized in that: An annular receiving groove which is concave relative to the guiding tooth portion is provided between the assembly tooth portion and the guiding tooth portion.

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