Rotor shaft, electric machine and rotor shaft assembly method

Abstract

The present application relates to a kind of rotor shaft, motor and rotor shaft assembly method.Rotor shaft, including shaft main body and shaft stretch, first end of shaft main body is provided with first assembly part, second end of shaft stretch is provided with second assembly part, first assembly part is provided with first assembly hole, second assembly part is provided with second assembly hole, first end is opposite with second end;Wherein one assembly part can be with second assembly part interference fit together to form mortise and tenon structure, in the interference fit state of first assembly part and second assembly part nesting, first assembly hole and second assembly hole correspond, fastener is embedded in first assembly hole and second assembly hole, wherein fastener and first assembly hole and second assembly hole interference fit.The present application can be combined with different shaft stretch to form different rotor shaft according to the need of shaft main body part, improve the versatility of motor.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and in particular to a rotor shaft, a motor, and a rotor shaft assembly method. Background Technology

[0002] As a power unit, servo motors often need to be assembled with reducers or other mechanical devices. The shaft extension length and shaft extension diameter of the servo motor are important dimensions for servo motors to be assembled with other equipment. In order to meet the actual assembly requirements, the rotor shaft often needs to be redesigned to meet the actual installation requirements.

[0003] Because servo motors have a wide range of applications, the required shaft extension dimensions for the same servo motor vary in different applications. To meet actual installation requirements, servo motors often need to be customized. Due to the different shaft extension dimensions, customized motor development not only increases the cost of purchasing servo motors for customers, but also increases the production and management costs for manufacturers due to the newly developed models. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a rotor shaft, a motor and a rotor shaft assembly method.

[0005] This invention provides a rotor shaft, including a shaft body and a shaft extension. A first assembly portion is provided at a first end of the shaft body, and a second assembly portion is provided at a second end of the shaft extension. The first assembly portion has a first assembly hole, and the second assembly portion has a second assembly hole. The first end and the second end are opposite to each other. The first assembly portion and the second assembly portion can be interference-fitted together to form a tenon and mortise structure. In the nested interference-fit state of the first assembly portion and the second assembly portion, the first assembly hole corresponds to the second assembly hole. Fasteners are embedded in the first assembly hole and the second assembly hole, wherein the fasteners are interference-fitted with the first assembly hole and the second assembly hole.

[0006] In some embodiments, the interference fit between the first assembly portion and the second assembly portion is in the range of 0.04 mm to 0.016 mm; and / or the interference fit between the fastener and the first assembly hole and the second assembly hole is in the range of 0.04 mm to 0.016 mm.

[0007] In some embodiments, the first mounting portion is a mortise formed at a first end of the shaft body, the mortise being formed concavely inward from the first end of the shaft body; the second mounting portion is a tenon formed at a second end of the shaft extension, the tenon being formed convexly outward from the second end of the shaft extension.

[0008] In some embodiments, the first mounting hole penetrates the side wall of the tenon and the outer peripheral wall of the shaft body to form a countersunk hole; the second mounting hole penetrates the tenon to form a through hole.

[0009] In some embodiments, the first mounting portion is a tenon formed at a first end of the shaft body, the tenon being formed to bulge outward from the first end of the shaft body towards the axially outward side; the second mounting portion is a mortise formed at a second end of the shaft extension, the mortise being formed to bulge inward from the second end of the shaft extension towards the axially inward side.

[0010] In some embodiments, the first mounting hole penetrates the tenon to form a through hole; the second mounting hole penetrates the side wall of the mortise and the outer peripheral wall of the shaft body to form a countersunk hole.

[0011] In some embodiments, both the first mounting hole and the second mounting hole extend radially toward the rotor shaft.

[0012] In some embodiments, the cross-sectional shapes of the first assembly portion and the second assembly portion are adapted to each other, and the shapes of the first assembly hole, the second assembly hole and the fastener are adapted to each other; wherein, the cross-sectional shapes of the first assembly portion and the second assembly portion are any one of rectangle, circle, trapezoid and dovetail; the shapes of the first assembly hole, the second assembly hole and the fastener are any one of rectangle, circle and trapezoid.

[0013] In some embodiments, the shaft extension includes a mating section and an extension section, the mating section being adjacent to the second mounting portion of the shaft extension for mounting a bearing, and the extension section being for connecting a load.

[0014] The present invention also provides an electric motor, comprising: a stator, a rotor, and a rotor shaft, wherein the rotor shaft is a rotor shaft as described in any of the embodiments mentioned above, and the rotor is fixed to the shaft body of the rotor shaft.

[0015] The present invention also provides a rotor shaft assembly method for assembling a rotor shaft as described in any of the embodiments mentioned above. The method includes: preheating the mortise of the tenon structure to a preheated state; inserting the tenon of the tenon structure into the preheated mortise to assemble the shaft body and shaft extension together, and aligning the first assembly hole with the second assembly hole; cooling the assembled shaft body and shaft extension to room temperature to form an interference fit between the tenon and the mortise; preheating the assembled shaft body and shaft extension again to a preheated state for the first and second assembly holes; inserting fasteners into the preheated first and second assembly holes and cooling to room temperature to form an interference fit between the fasteners and the first and second assembly holes.

[0016] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0017] The rotor shaft structure of this invention is divided into two parts: a shaft extension and a shaft body. The shaft extension and shaft body are then joined together by a first assembly part and a second assembly part to form a mortise and tenon structure. Fasteners are then inserted into the first and second assembly holes and fitted together to restrict axial displacement of the shaft extension and shaft body, thus forming a complete rotor shaft. The shaft body can be combined with shaft extensions of different lengths and / or diameters to form different rotor shafts as needed. This allows for changes in the shaft extension dimensions to meet different assembly requirements without affecting the motor's performance, significantly reducing motor production costs and improving the motor's versatility.

[0018] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0019] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0020] Figure 1 This is a schematic diagram of a motor structure according to an exemplary embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of a shaft extension structure at different angles according to an exemplary embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the shaft body structure at different angles according to an exemplary embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of a fastener structure at different angles according to an exemplary embodiment of the present invention;

[0024] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0025] In the description of this invention, it should be noted that the terms "inner" and "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "contact," and "communication" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] This invention provides a rotor shaft with variable shaft extension. Without affecting the performance of the motor itself, the shaft extension size can be changed according to the assembly requirements of different occasions, which greatly reduces the production cost of the motor and improves the versatility of the motor.

[0028] like Figures 1 to 4 As shown, the rotor shaft of this embodiment of the invention includes a shaft body 11 and a shaft extension 12. A first mounting portion 13 is provided at the first end 101 of the shaft body 11, and a second mounting portion 14 is provided at the second end 102 of the shaft extension 12. The first mounting portion 13 has a first mounting hole 131, and the second mounting portion 14 has a second mounting hole 141. The first end 101 and the second end 102 are opposite to each other. The first mounting portion 13 and the second mounting portion 14 can be interference-fitted together to form a tenon and mortise structure. In the nested assembly state of the first mounting portion 13 and the second mounting portion 14, the first mounting hole 131 and the second mounting hole 141 correspond to each other. Fasteners 15 are embedded in the first mounting hole 131 and the second mounting hole 141, wherein the fasteners 15 are interference-fitted with the first mounting hole 131 and the second mounting hole 141, thereby forming the shaft body 11 and the shaft extension 12 into a whole.

[0029] The shaft body 11, shaft extension 12, and fastener 15 can be made of 45# steel or other materials that meet structural strength and processing requirements. The specific assembly process is as follows:

[0030] First, the mortise and tenon joint is preheated to a preheated state. When preheated, the opening of the mortise and tenon joint is slightly larger than at room temperature to facilitate the insertion of the tenon.

[0031] Next, the tenon of the mortise and tenon structure is inserted into the mortise in the preheated state, so that the shaft body 11 and the shaft extension 12 are assembled together, and the first assembly hole corresponds to the second assembly hole. The mortise in the preheated state allows the tenon of the mortise and tenon structure to be smoothly inserted into the mortise, achieving an interference fit.

[0032] Next, the assembled shaft body 11 and shaft extension 12 are cooled to room temperature, so that the tenon and mortise form an interference fit. The mortise and tenon structure, cooled to room temperature, forms an interference fit, making the shaft body 11 and shaft extension 12 a single unit.

[0033] Then, the assembled shaft body and shaft extension are preheated again, so that the first and second mounting holes are in a preheated state. With the shaft body and shaft extension already assembled, i.e., the mortise and tenon structure already in an interference fit state, a pre-treatment is performed to make the space in the first and second mounting holes slightly larger, to facilitate the insertion of fasteners.

[0034] Finally, the fastener 15 is inserted into the first and second mounting holes in the preheated state and cooled to room temperature, so that the fastener is interference-fitted with the first and second mounting holes to limit the axial displacement of the shaft extension 12 and the shaft body 11.

[0035] The rotor shaft structure of this invention is divided into two parts: a shaft extension 12 and a shaft body 11. The shaft extension 12 and the shaft body 11 are then joined by a first assembly part 13 and a second assembly part 14 through an interference fit to form a mortise and tenon structure. Fasteners 15 are then inserted into the first assembly hole 131 and the second assembly hole 141 and interference fit to restrict axial displacement of the shaft extension 12 and the shaft body 11, thus forming a complete rotor shaft. The shaft body 11 can be combined with shaft extensions 12 of different lengths and / or diameters to form different rotor shafts as needed. This allows for changes in the shaft extension dimensions to meet different assembly requirements without affecting the motor's performance, significantly reducing motor production costs and improving the motor's versatility.

[0036] In some embodiments, the interference fit between the first assembly part 13 and the second assembly part 14 is not less than 0.04 mm, preferably in the range of 0.04 mm to 0.016 mm; and / or the interference fit between the fastener 15 and the first assembly hole 131 and the second assembly hole 141 is not less than 0.04 mm, preferably in the range of 0.04 mm to 0.016 mm. Such an interference fit allows for changes in shaft extension dimensions according to assembly requirements in different situations without affecting rotor shaft performance, greatly reducing motor production costs and improving motor versatility.

[0037] In some examples, such as Figure 2 and Figure 3As shown, the first mounting portion 13 is a mortise 13 formed at the first end 101 of the shaft body 11, which is recessed inward from the first end face of the shaft body 11. A first mounting hole 131 penetrates the side wall of the mortise 13 and the outer peripheral wall of the shaft body 11 to form a countersunk hole, meaning the first mounting hole 131 and the mortise 13 are connected. The second mounting portion 14 is a tenon 14 formed at the second end of the shaft extension 12, which protrudes outward from the second end face of the shaft extension 12. A second mounting hole 141 penetrates the tenon 14 to form a through hole. For example, the first mounting hole 131 extends along the radial direction of the shaft body 11. The second mounting hole 141 extends along the radial direction of the shaft extension 12. The mortise 13 and the tenon 14 can be matched in shape and size to satisfy an interference fit.

[0038] In other examples, the first mounting part 13 is a tenon formed at the first end of the shaft body 11, the tenon being formed by protruding outward from the first end of the shaft body 11 towards the axial direction, and the first mounting hole 131 passing through the tenon to form a through hole; the second mounting part 14 is a mortise formed at the second end of the shaft extension 12, the mortise being formed by concave inward from the second end of the shaft extension 12 towards the axial direction, and the second mounting hole 141 passing through the side wall of the mortise and the outer peripheral wall of the shaft body to form a countersunk hole.

[0039] In other words, the mortise and tenon of the mortise and tenon structure formed by the rotor shaft of the present invention can be interchanged in the positions of the shaft body 11 and the shaft extension.

[0040] In some embodiments, the cross-sectional shapes of the first assembly portion 13 and the second assembly portion 14 are adapted to each other, and the shapes of the first assembly hole 131, the second assembly hole 141 and the fastener 15 are adapted to each other.

[0041] As examples, the cross-sectional shapes of the first assembly part 13 and the second assembly part 14 are any one of rectangle, circle, trapezoid, and dovetail shapes, but are not limited to these; they can also be other shapes that can be adapted to be joined together. The shapes of the first assembly hole 131, the second assembly hole 141, and the fastener 15 are any one of rectangle, circle, and trapezoid. But they are not limited to these; they can also be other shapes that can be adapted to be joined together.

[0042] In some embodiments, such as Figure 1As shown, the shaft extension 12 includes a mating section 121 and an extension section 122. The bearing mating section 121 is adjacent to the second mounting portion 14 of the shaft extension 12 and is used to assemble the bearing 32. The extension section 122 is used to connect the load. The mating section 121 and the extension section 122 of the shaft extension 12 form a stepped shaft. The outer diameter of the mating section 121 is larger than the outer diameter of the extension section 122, and a protruding tenon can be formed by extending the front end face of the mating section 121. The mating section 121 for assembling the bearing 32 is adjacent to the second mounting portion 14 of the shaft extension 12, which can suppress the wobble of the rotor shaft caused by assembly tolerances to the greatest extent. When the shaft extension 12 is subjected to radial force, with the bearing as the fulcrum, the second assembly part 14 will be subjected to radial force opposite to that of the shaft extension 12. This will cause the motor shaft to wobble during motor operation. However, the tenon and mortise structure design and interference fit of the bearing mating section 112, the motor mating section 111 and the fastener 15 can make the forces of the bearing mating section 112, the motor mating section 111 and the fastener 15 mutually restrict each other, thereby reducing the wobble of the rotor shaft caused by assembly tolerance.

[0043] The shaft body 11 includes a detection section 113, a bearing mating section 112, and a motor mating section 111. At least a portion of the motor mating section 111 is fixed with a motor rotor 22, which is located near the first assembly part 13. The bearing mating section 112 is used to install a bearing 21, and the detection section 113 is used to install an encoder 50.

[0044] This invention also provides a motor, including a stator 21, a rotor 22, and a rotor shaft. The rotor shaft is as described in any of the embodiments mentioned above, and the rotor is fixed to the shaft body 11 of the rotor shaft. A front bearing 31 is supported on a mating section 112 (which may be referred to as the first mating section 112) of the shaft body 11, and a rear bearing 32 is supported on a mating section 121 (which may be referred to as the second mating section 121) of the shaft extension 12. The motor also includes a front end cover 41 supporting the front bearing 31, a rear end cover 42 supporting the rear bearing 32, an encoder 50 mounted on a detection section 113 of the shaft body 11, and an encoder cover 60 connected to the front end cover 41 and covering the encoder 50.

[0045] The motor of the present invention allows the shaft body 11 to be combined with shaft extensions 12 of different lengths and / or different diameters to form different rotor shafts as needed. In this way, without affecting the performance of the motor itself, the shaft extension size can be changed according to the assembly requirements of different occasions, which greatly reduces the production cost of the motor and improves the versatility of the motor.

[0046] This invention also provides a rotor shaft assembly method for assembling a rotor shaft as described in any of the above embodiments, the method comprising:

[0047] Step 1: Preheat the mortise and tenon joint to ensure it is in a preheated state. The opening of the mortise will be slightly larger when preheated than at room temperature to facilitate the insertion of the tenon.

[0048] Step 2: Insert the tenon of the mortise and tenon structure into the mortise in the preheated state, assembling the shaft body 11 and the shaft extension 12 together, and aligning the first assembly hole with the second assembly hole. The preheated mortise allows the tenon of the mortise and tenon structure to smoothly insert into the mortise, achieving an interference fit.

[0049] Step 3: Cool the assembled shaft body 11 and shaft extension 12 to room temperature, so that the tenon and mortise form an interference fit. The mortise and tenon structure, cooled to room temperature, forms an interference fit, making the shaft body 11 and shaft extension 12 a single unit.

[0050] Step 4: Preheat the assembled shaft body and shaft extension again to preheat the first and second mounting holes. With the shaft body and shaft extension already assembled (i.e., the mortise and tenon structure already in an interference fit), perform a pre-setting process to slightly increase the space in the first and second mounting holes to facilitate the insertion of fasteners.

[0051] Step 5: Insert the fastener 15 into the first and second assembly holes in the preheated state, and cool it to room temperature so that the fastener is interference-fitted with the first and second assembly holes to limit the axial displacement of the shaft extension 12 and the shaft body 11.

[0052] It can be further understood that in this disclosure, "multiple" refers to two or more, and other quantifiers are similar. "And / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. The singular forms "a," "the," and "the" are also intended to include the plural forms unless the context clearly indicates otherwise.

[0053] It is further understood that the terms "first," "second," etc., are used to describe various types of information, but this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another, and do not indicate a specific order or degree of importance. In fact, the expressions "first," "second," etc., are completely interchangeable. For example, without departing from the scope of this disclosure, first information can also be referred to as second information, and similarly, second information can also be referred to as first information.

[0054] It is further understood that although operations are described in a specific order in the accompanying drawings in this disclosure, this should not be construed as requiring these operations to be performed in the specific order or serial order shown, or requiring all of the shown operations to obtain the desired result. In certain environments, multitasking and parallel processing may be advantageous.

[0055] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the following claims.

[0056] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A rotor shaft, characterized in that, Including the shaft body and shaft extension, A first assembly part is provided at the first end of the shaft body, and a second assembly part is provided at the second end of the shaft extension. The first assembly part is provided with a first assembly hole, and the second assembly part is provided with a second assembly hole. The first end and the second end are opposite to each other. The first assembly part can be interference-fitted with the second assembly part to form a tenon and mortise structure. When the first assembly part and the second assembly part are interference-fitted, the first assembly hole corresponds to the second assembly hole. Fasteners are embedded in the first assembly hole and the second assembly hole, wherein the fasteners are interference-fitted with the first assembly hole and the second assembly hole. The interference fit between the first assembly part and the second assembly part is in the range of 0.04mm to 0.016mm; and / or the interference fit between the fastener and the first assembly hole and the second assembly hole is in the range of 0.04mm to 0.016mm.

2. The rotor shaft according to claim 1, characterized in that, The first assembly part is a mortise formed at the first end of the shaft body, the mortise being formed concavely inward from the first end of the shaft body facing axially; The second assembly part is a tenon formed at the second end of the shaft extension, the tenon being formed by the second end of the shaft extension protruding axially outward.

3. The rotor shaft according to claim 2, characterized in that, The first assembly hole penetrates the inner wall of the mortise and the outer peripheral wall of the shaft body to form a countersunk hole; The second assembly hole penetrates the tenon to form a through hole.

4. The rotor shaft according to claim 2, characterized in that, The first assembly part is a tenon formed at the first end of the shaft body, the tenon being formed by protruding outward from the first end of the shaft body towards the axial direction; The second assembly part is a mortise formed at the second end of the shaft extension, the mortise being formed concavely from the second end of the shaft extension toward the axially inward side.

5. The rotor shaft according to claim 4, characterized in that, The first assembly hole penetrates the tenon to form a through hole; The second assembly hole penetrates the inner wall of the mortise and the outer peripheral wall of the shaft body to form a countersunk hole.

6. The rotor shaft according to claim 1, characterized in that, Both the first mounting hole and the second mounting hole extend radially toward the rotor shaft.

7. The rotor shaft according to claim 1, characterized in that, The cross-sectional shapes of the first assembly part and the second assembly part are adapted to each other. The shapes of the first mounting hole, the second mounting hole, and the fastener are compatible; Wherein, the cross-sectional shape of the first assembly part and the second assembly part is any one of rectangle, circle, trapezoid, or dovetail shape; The first mounting hole, the second mounting hole, and the fastener are any one of rectangular, circular, or trapezoidal shapes.

8. The rotor shaft according to any one of claims 1-7, characterized in that, The shaft extension includes a mating section and an extension section. The mating section is adjacent to the second mounting portion of the shaft extension and is used to assemble a bearing. The extension section is used to connect a load.

9. An electric motor, characterized in that, include: Stator, rotor, and rotor shaft, wherein the rotor shaft is the rotor shaft as described in any one of claims 1-8. The rotor is fixed to the shaft body of the rotor shaft.

10. A rotor shaft assembly method, characterized in that, The method for assembling a rotor shaft as described in any one of claims 1-8 comprises: The mortise and tenon joint is preheated to put it in a preheated state. The tenon of the mortise and tenon structure is inserted into the mortise in the preheated state, so that the shaft body and the shaft extension are assembled together, and the first assembly hole corresponds to the second assembly hole. The assembled shaft body and shaft extension are cooled to room temperature, so that the tenon and mortise form an interference fit; The assembled shaft body and shaft extension are preheated again to put the first and second assembly holes in a preheated state. The fastener is inserted into the first and second mounting holes in the preheated state and cooled to room temperature, so that the fastener is interference-fitted with the first and second mounting holes.

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