Permanent magnet electric drive assembly bearing chamber wave spring installation and fixing tool and its use method

Abstract

The present invention discloses a fixture for installing and fixing a wave spring in a bearing chamber of a permanent magnet electric drive assembly and a method for using the fixture. The fixture includes a base and a plurality of elastic claws. A positioning surface and a connector are provided on the base. The plurality of elastic claws are distributed circumferentially along the base. One end of the elastic claw is fixedly connected to the base, and the other end of the elastic claw protrudes from the base. The end of the elastic claw protruding from the base is in the shape of a reverse hook. The fixture of the present invention is provided with a plurality of elastic claws. An installation space for the elastic claws is reserved on the bearing chamber by drilling holes or opening windows, so that the elastic claws in the fixture can be extended into the bearing chamber. The fixture is assembled as a whole in the bearing chamber through the positioning surface and connector on the base, thereby solving the problem of the flat pad and wave spring falling off in the bearing chamber at the tail end of the motor when the stator and rotor are combined. After the stator and rotor are assembled, the rear bearing of the rotor is pressed into the bearing chamber and a withdrawal force is applied to the elastic claws, and the fixture is withdrawn smoothly.

Description

Technical Field

[0001] The present invention relates to the technical field of electric drive systems for new energy vehicles, and in particular to a tool for installing and fixing a wave spring in a bearing chamber of a permanent magnet electric drive assembly and a method for using the tool. Background Art

[0002] The electric drive system is a core component of new energy vehicles, responsible for converting electrical energy into mechanical power to propel the vehicle forward. It typically consists of multiple components, including the drive motor, motor controller, and transmission. The development of the electric drive system directly impacts the power output, energy efficiency, range, and safety of new energy vehicles.

[0003] Currently, most new energy vehicles on the market use permanent magnet motors as the driving device for their electric drive systems. When using a permanent magnet motor as the driving device for an electric drive system, the motor's rotor and the reduction gearbox input shaft share three bearings. The motor has only a rear bearing, and the motor housing is equipped with a bearing chamber. The bearing chamber design primarily includes a wave spring + rear bearing + bearing inner cover, a wave spring + rear bearing with a fixed cover, and a wave spring + rear bearing.

[0004] When a system using a permanent magnet motor as an electric drive adopts a wave spring + rear bearing structure, the bearing chamber occupies less axial space, the product structure is simple, the bearing chamber structure size is minimized, materials are saved, the overall cost is lowest, and it has the greatest development and exploration value. However, at this stage, systems using permanent magnet motors as electric drives rarely adopt the wave spring + rear bearing structure. This is mainly because this structure has the following process assembly problems: Since new energy electric drive systems need to reduce weight, the motor housing is made of aluminum alloy. The wear resistance of the bearing chamber end face (the wave spring repeatedly squeezes the aluminum end face) will produce pits, so a flat washer needs to be added between the wave spring and the motor housing. For permanent magnet motors as electric drive systems, because the rotor and reducer are connected through internal and external splines, and the rotor is a permanent magnet structure, the rotor must be at the bottom when the stator and rotor of the permanent magnet motor are assembled, and the assembly equipment supports and fixes the rotor through the middle hole to prevent the stator core and the rotor permanent magnet from being magnetically attracted and deflected during the assembly process. The stator part of the motor needs to be assembled from top to bottom with the bearing chamber facing downward, which will cause the flat washer and wave spring in the bearing chamber to fall out of the bearing chamber during the assembly process. Therefore, how to fix the wave spring and flat washer is the key and difficulty in the assembly process. Summary of the Invention

[0005] In view of the above shortcomings of the prior art, the technical problem to be solved by the present invention is: how to provide a device that can stably fix the flat washer and the wave spring in the bearing chamber with the opening facing downward, so that the stator and the rotor can automatically flip and load the material when the box is assembled.

[0006] A permanent magnet electric drive assembly bearing chamber wave spring installation and fixing tool and its use method that can automatically clamp and fix, automatically close the box without falling, and can simply be recycled.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A permanent magnet electric drive assembly bearing chamber wave spring installation and fixing tool includes a base and multiple elastic claws. A positioning surface and a connecting piece are provided on the base. The multiple elastic claws are distributed along the circumference of the base. One end of the elastic claw is fixedly connected to the base, and the other end of the elastic claw protrudes from the base. The end of the elastic claw protruding from the base is in the shape of an inverted hook.

[0009] Preferably, there are three elastic claws distributed along the circumference of the base, and the three elastic claws form a circular structure. One end of the elastic claw in the reverse hook shape has an arc structure protruding outward, and the arc structure of the three elastic claws forms a discontinuous drum ring.

[0010] Preferably, a positioning stop is provided on the base at a position connected to the elastic claw, the elastic claw is located at the positioning stop, and the elastic claw is fixedly connected to the base via a connecting bolt.

[0011] A method for using the above-mentioned permanent magnet electric drive assembly bearing chamber wave spring installation and fixing tool comprises the following steps:

[0012] Step 1) machining a plurality of through holes at the bearing chamber of the motor housing, wherein the number and positions of the through holes correspond one-to-one to the elastic claws;

[0013] Step 2) Extend the elastic claws from the outside of the bearing chamber through the corresponding through-holes into the bearing chamber, and connect the base to the bearing chamber through the positioning surface and the connector;

[0014] Step 3) Retract the elastic claws inward and install the flat washer and wave spring in sequence, then expand the elastic claws outward and reset them to secure the wave spring and flat washer.

[0015] Step 4) When assembling the stator and rotor, the rear bearing of the rotor is pressed into the bearing chamber and an outward force is applied to the elastic claws, causing the elastic claws to exit the bearing chamber through the through hole and exit the tooling.

[0016] Preferably, there are three elastic claws distributed along the circumference of the base, and the three elastic claws form a quasi-circular structure. The end of the elastic claw in the shape of a reverse hook has an arc structure protruding outward, and the arc structure of the three elastic claws forms a discontinuous drum ring; and the diameter of the largest outer circle formed by the arc structure of the three elastic claws is larger than the inner diameter of the wave spring.

[0017] Preferably, the diameter of the largest outer circle formed by the three elastic claw arc structures is 4-7 mm larger than the inner diameter of the wave spring.

[0018] Preferably, the diameter of the largest outer circle formed by the three elastic claw arc structures is 5 mm larger than the inner diameter of the wave spring.

[0019] Preferably, the positioning surface on the base is an outer stop surface, and the connecting parts are multiple glass ball screws arranged at different circumferential positions of the base, and each of the glass ball screws is radially installed on the outer stop surface.

[0020] Preferably, the elastic claws are made of elastic steel structure, elastic plastic, or elastic non-ferrous metal.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. The tooling of the present invention is provided with three or more elastic claws. Installation space for the elastic claws is reserved on the bearing chamber by drilling holes or opening windows, so that the elastic claws in the tooling can be extended into the bearing chamber, and the tooling as a whole is assembled in the bearing chamber through the positioning surface and connectors on the base. The elastic claws are in the shape of reverse hooks, and multiple elastic claws are distributed to form a quasi-circular shape. The elastic claws are elastic, and the elastic claws shrink inward to fit the flat washers and wave springs on them, and then they are fixed in the bearing chamber by resetting and stretching outwards, thereby solving the problem of the flat washers and wave springs falling off in the bearing chamber at the tail end of the motor when the stator and rotor are combined. After the stator and rotor are assembled, the rear bearing of the rotor is pressed into the bearing chamber and exerts an exit side force on the elastic claws, and the tooling is smoothly withdrawn. The tooling is easy to recycle and can be reused.

[0023] 2. This invention uses tooling to solve the problem of flat washers and wave springs falling during assembly. This allows the steel insert in the bearing chamber to be replaced with a flat washer, significantly optimizing the motor casing processing (deep hole finishing of two soft and hard materials becomes deep hole finishing of the same material). This effectively reduces processing costs and improves machining precision in mass production. Each unit saves 30-50 yuan in manufacturing costs (including the cost of insert casting and tool wear for finishing the two materials). The use of elastic claws to secure the wave spring replaces the bearing inner cover and inner cover assembly, eliminating the need for a bearing inner cover or C-type retaining ring. This saves 5-10 yuan in manufacturing costs per unit (including the cost of bearing chamber extension materials, bearing inner cover, and C-type retaining ring), effectively facilitating the mass production of permanent magnet electric drive systems.

[0024] 3. The present invention solves the problem of wave spring falling off when the stator and rotor of the permanent magnet motor have a wave spring + flat washer + rear bearing structure; solves the problem of wave spring falling off when the stator is flipped 180°; and provides a solid process manufacturing guarantee for the optimization of the electric drive structure.

[0025] 4. The tooling of the present invention is easy to manufacture, has a stable fixing method, is easy to assemble and disassemble, and tooling of different sizes is suitable for fixing with different types of wave springs.

[0026] 5. The present invention can stably fix the flat washer and the wave spring in the bearing chamber with the opening facing downward, so that the stator and the rotor can be automatically turned over and loaded, automatically clamped and fixed, and automatically closed without falling during assembly. In addition, the tooling can be easily recovered and reused. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Attachment Figure 1 It is a structural diagram of a permanent magnet motor electric drive system in the prior art;

[0028] Attachment Figure 2 A schematic diagram of the structure of the permanent magnet electric drive assembly bearing chamber wave spring mounting and fixing tooling of the present invention;

[0029] Attachment Figure 3 A schematic diagram of the arrangement of through holes on the motor housing in the method for using the fixture for mounting and fixing the wave spring in the bearing chamber of the permanent magnet electric drive assembly of the present invention;

[0030] Attachment Figure 4 Structural dimension diagram of the flat washer of the permanent magnet electric drive assembly bearing chamber wave spring installation and fixing tooling of the present invention;

[0031] Attachment Figure 5 A structural dimension diagram of the wave spring in the method for using the fixture for mounting and fixing the wave spring in the bearing chamber of the permanent magnet electric drive assembly of the present invention;

[0032] Attachment Figure 6 A structural dimension diagram of the elastic claws used in the method for using the fixture for installing and fixing the wave spring in the bearing chamber of the permanent magnet electric drive assembly of the present invention;

[0033] Attachment Figure 7 Structural dimension diagram of the base in the method for using the tooling for installing and fixing the wave spring in the bearing chamber of the permanent magnet electric drive assembly of the present invention.

[0034] Explanation of the accompanying drawings: rotor 1, reduction gearbox input shaft 2, rear bearing 3, bearing chamber 4, wave spring 5, flat washer 6, motor housing 7, through hole 701, stator 8, elastic claw 9, base 10, connector 11, positioning surface 12. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0036] When using a permanent magnet motor as the driving device of an electric drive system, Figure 1 As shown, the motor's rotor 1 and the reduction gearbox input shaft 2 share three bearings. The motor has only a rear bearing 3, and a bearing chamber 4 is located in the motor housing 7. The design options for bearing chamber 4 include a wave spring + rear bearing + inner bearing cover, a wave spring + rear bearing with a fixed cover, and a wave spring + rear bearing. Table 1 shows the advantages and disadvantages of each design.

[0037] Table 1: Advantages and disadvantages of various structural forms of bearing chambers

[0038] Structural form advantage shortcoming Wave spring + rear bearing + bearing inner cover 1. Axial fixed dimension control quality is stable and reliable; 2. The structure is adapted to the diameter of each shaft 1. The assembly is complicated, requiring an additional assembler to tighten the bolts; the labor cost is high; 2. The axial space occupied is large, which is not conducive to volume reduction; 3. The bearing chamber structure size becomes larger, and the material cost is high; Wave spring + rear bearing with fixed cover 1. The axial fixed dimension control quality is stable and reliable; 2. Compared with the inner cover structure, the axial space is less occupied; 3. Compared with the inner cover structure, the bearing chamber structure size is smaller; 1. The assembly is complicated, and an additional assembler is required to tighten the bolts; the labor cost is high; 2. The bearings come with fixed cover plates in limited models, and the price is high. Wave spring + rear bearing 1. Small axial space occupation and simple product structure. 2. Minimum bearing chamber structure size, saving materials. 3. Lowest overall cost. 1. The assembly structure is complex, the wave spring cannot be fixed, and batch production is difficult

[0039] As can be seen from the table above, the wave spring + rear bearing structure takes up less axial space in the bearing chamber, has a simple product structure, minimizes the bearing chamber structure size, saves materials, and has the lowest overall cost, making it the most promising for development and exploration. However, currently, systems using permanent magnet motors as electric drives rarely use the wave spring + rear bearing structure, mainly because this structure has the following assembly process problems:

[0040] 1. Due to the need to reduce weight in new energy electric drive systems, the motor housing is made of aluminum alloy. The end face of the bearing housing is resistant to wear (the wave spring repeatedly presses against the aluminum end face), which can cause pitting. Therefore, a flat washer is required between the wave spring and the motor housing. When assembling the flat washer and wave spring, the bearing housing opening should face upward.

[0041] 2. For permanent magnet motors as electric drive systems, because the rotor and reducer are connected through internal and external splines, and the rotor is a permanent magnet structure, the rotor must be at the bottom when the stator and rotor of the permanent magnet motor are assembled, and the assembly equipment supports and fixes the rotor through the middle hole to prevent the stator core and the rotor permanent magnet from being magnetically attracted and deflected during the assembly process. The stator part of the motor needs to be assembled from top to bottom with the bearing chamber facing down, which will cause the flat washer and wave spring in the bearing chamber to fall out of the bearing chamber during the assembly process.

[0042] 3. After the flat washers and wave springs are placed on the motor stator, it needs to be flipped 180°. At the same time, when the stator is fixed on the assembly equipment, it is subjected to a certain impact and the flat washers and wave springs may fall off.

[0043] 4. Many bearings in new energy electric drives use oil cooling, so flat washers and wave springs cannot be fixed with grease. This involves oil and grease compatibility, oxidation resistance, etc.

[0044] In order to solve the problem of falling easily existing when using flat washers and wave springs, this specific embodiment first provides a permanent magnet electric drive assembly bearing chamber wave spring installation and fixing tool, as shown in the attached Figure 2 As shown, the tooling includes a base 10 and multiple elastic claws 9. The base 10 is provided with a positioning surface 12 and a connector 11. In this specific embodiment, the positioning surface 12 is an outer stop surface, and the connector 11 is a plurality of glass bead screws arranged at different positions around the base 10, and each glass bead screw is radially mounted on the outer stop surface. Multiple elastic claws 9 are distributed along the circumference of the base 10. One end of the elastic claw 9 is fixedly connected to the base 10, and the other end of the elastic claw 9 protrudes from the base 10. The end of the elastic claw 9 protruding from the base 10 is in the shape of an inverted barb. The elastic claw 9 is made of elastic steel structure, elastic plastic, or elastic non-ferrous metal.

[0045] In this specific embodiment, three elastic claws 9 are distributed circumferentially along the base 10. These claws 9 form a quasi-circular structure. The reversed barbed ends of the claws 9 have an outwardly protruding arc, forming a discontinuous, bulging ring shape. The maximum outer diameter of the arcuate structure of the three elastic claws 9 is larger than the inner diameter of the wave spring. In this specific embodiment, the maximum outer diameter of the arcuate structure of the three elastic claws 9 is 5 mm larger than the inner diameter of the wave spring.

[0046] In this specific embodiment, a positioning stop is provided on the base 10 at a position connected to the elastic claw 9 , the elastic claw 9 is located at the positioning stop, and the elastic claw 9 is fixedly connected to the base 10 via a connecting bolt.

[0047] In addition, this specific embodiment also provides a method for using a permanent magnet electric drive assembly bearing chamber wave spring installation and fixing tool, including the following steps:

[0048] Step 1) Process multiple through holes at the bearing chamber 4 of the motor housing 7. The number and position of the through holes correspond to the elastic claws 9 one by one. Figure 3 As shown, three through holes 701 are reserved at the bearing chamber 4 of the motor housing 7, and three holes with a diameter of 8.5 are designed and processed to allow the elastic claws 9 on the tooling to extend into the bearing chamber 4 and contact the flat washer 6 and the wave spring 5.

[0049] Step 2) Insert the elastic claw 9 from the outside of the bearing chamber 4 through the corresponding through-hole. Connect the base 10 to the bearing chamber 4 via the positioning surface 12 and the connector 11. In mass production, because the bearing chamber 4 is located at the rear end of the motor, components (flat washers and wave springs) require deep-hole installation. For optimal ergonomics, install the fixture from top to bottom. Therefore, the fixture should be installed from bottom to top. The electric cylinder lifts the fixture upward from the bottom. The fixture is secured with the external stopper screws on the base 10.

[0050] Step 3) Retract the elastic claw 9 inward and install the flat washer 6 and wave spring 5 in sequence, then expand the elastic claw 9 outward and reset it to fix the wave spring 5 and flat washer 6. Because the inner circle size of the flat washer is less than the inner circle size of the wave spring, the inner circle size of the flat washer is as shown in the attached figure. Figure 4 The figure is ɸ59mm, the inner circle size of the wave spring is as shown in the attached Figure 5 The figure shows ɸ61.15mm. First, install the flat washer, and the inner circle size of the tooling elastic clamping claw 9 after it shrinks inward must be less than ɸ59mm. Then install the wave spring, and the inner circle size of the tooling after it is stretched out must be greater than ɸ61.15mm. Since the stator needs to be flipped 180° in the later stage, the bearing chamber opening faces downward, and the wave spring does not fall off, the inner circle size of the tooling after it is stretched out must be much greater than ɸ61.15, which is ɸ65mm in this specific embodiment. The tooling is made of spring steel material (60Si2Mn) and heat-treated (C45) to give it good elasticity. At the same time, a special elastic clamping claw 9 with a fishhook barb structure is designed, and the size of the elastic clamping claw 9 is as shown in the attached figure. Figure 6 As shown, the base 10 size is as shown in the attached Figure 7 shown.

[0051] Step 4) When assembling the stator and rotor, the rotor rear bearing is pressed into the bearing chamber and exerts an outward force on the elastic claw 9, so that the elastic claw 9 withdraws from the bearing chamber through the through hole and withdraws from the tooling.

[0052] Compared to the prior art, the fixture of the present invention comprises three or more elastic claws 9 disposed on a base 10. The fixture is fixed to the tail end of the stator, and installation space for the elastic claws 9 is reserved in the bearing chamber by drilling holes or opening windows, allowing the elastic claws 9 in the fixture to be inserted into the bearing chamber. The fixture is then assembled in the bearing chamber via the positioning surfaces 12 and connectors 11 on the base 10. The elastic claws 9 are in the shape of reversed barbs, with multiple elastic claws 9 distributed in a quasi-circular shape. The elastic claws 9 are elastic and contract inward to fit the flat washer and wave spring over them. The claws then reposition and expand outward to secure the flat washer and wave spring in the bearing chamber, thus resolving the problem of the flat washer and wave spring falling out of the bearing chamber at the tail end of the motor when the stator and rotor are assembled. After the stator and rotor are assembled, the rear rotor bearing is pressed into the bearing chamber and applies a withdrawal force to the elastic claws 9, allowing the fixture to be smoothly withdrawn. The fixture is easy to recycle and can be reused.

[0053] This invention uses tooling to solve the problem of flat washers and wave springs falling during assembly. This allows the steel insert in the bearing chamber to be replaced with a flat washer, significantly optimizing the motor casing machining process (deep hole finishing of two soft and hard materials becomes deep hole finishing of the same material). This effectively reduces machining costs and improves machining precision in mass production. Each unit saves 30 to 50 yuan in manufacturing costs (including the cost of insert casting and tool wear for finishing the two materials). The use of elastic claws 9 to secure the wave spring replaces the bearing inner cover and inner cover assembly, eliminating the need for a bearing inner cover or C-ring. This saves 5 to 10 yuan in manufacturing costs per unit (including the cost of bearing chamber extension materials, bearing inner cover, and C-ring), effectively facilitating the mass production of permanent magnet electric drive systems.

[0054] The present invention solves the problem of wave spring falling off when the stator and rotor of a permanent magnet motor with a wave spring + flat washer + rear bearing structure is assembled; solves the problem of wave spring falling off when the stator is flipped 180°; and provides a solid process manufacturing guarantee for the optimization of the electric drive structure.

[0055] The tooling of the present invention is simple to manufacture, has a stable fixing method, is convenient to assemble and disassemble, and tooling of different sizes is suitable for fixing with wave springs of different models.

[0056] The present invention can stably fix the flat washer and the wave spring in the bearing chamber with the opening facing downward, so that the stator and the rotor can be automatically turned over and loaded, automatically clamped and fixed, and automatically closed without falling during the assembly process, and the tooling can be simply recovered and reused.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the technical solutions. Those skilled in the art should understand that modifications or equivalent replacements of the technical solutions of the present invention that do not depart from the purpose and scope of the technical solutions of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for using a tool for installing and fixing a wave spring in a bearing chamber of a permanent magnet electric drive assembly, characterized in that: The permanent magnet electric drive assembly bearing chamber wave spring mounting and fixing tool comprises a base and a plurality of elastic claws, a positioning surface and a connecting piece are provided on the base, the plurality of elastic claws are distributed along the circumference of the base, one end of the elastic claw is fixedly connected to the base, the other end of the elastic claw protrudes from the base, and the end of the elastic claw protruding from the base is in the shape of a reverse hook; The following steps are involved: Step 1) machining a plurality of through holes at the bearing chamber of the motor housing, wherein the number and positions of the through holes correspond one-to-one to the elastic claws; Step 2) Extend the elastic claws from the outside of the bearing chamber through the corresponding through-holes into the bearing chamber, and connect the base to the bearing chamber through the positioning surface and the connector; Step 3) Retract the elastic claws inward and install the flat washer and wave spring in sequence, then expand the elastic claws outward and reset them to secure the wave spring and flat washer. Step 4) When assembling the stator and rotor, the rear bearing of the rotor is pressed into the bearing chamber and an outward force is applied to the elastic claws, causing the elastic claws to exit the bearing chamber through the through hole and exit the tooling.

2. The method for using the permanent magnet electric drive assembly bearing chamber wave spring installation and fixing tool according to claim 1 is characterized in that: A positioning stop is provided on the base at a position connected to the elastic claw. The elastic claw is located at the positioning stop, and the elastic claw is fixedly connected to the base via a connecting bolt.

3. The method for using the permanent magnet electric drive assembly bearing chamber wave spring installation and fixing tool according to claim 1 is characterized in that: There are three elastic claws distributed along the circumference of the base, and the three elastic claws form a circular-like structure. The end of the elastic claw in the shape of a reverse hook has an arc structure protruding outward, and the arc structure of the three elastic claws forms a discontinuous drum ring; and the diameter of the largest outer circle formed by the arc structure of the three elastic claws is larger than the inner diameter of the wave spring.

4. The method for using the permanent magnet electric drive assembly bearing chamber wave spring installation and fixing tool according to claim 3 is characterized in that: The diameter of the largest outer circle formed by the three elastic claw arc structures is 4-7 mm larger than the inner diameter of the wave spring.

5. The method for using the permanent magnet electric drive assembly bearing chamber wave spring installation and fixing tool according to claim 4 is characterized in that: The diameter of the largest outer circle formed by the three elastic claw arc structures is 5 mm larger than the inner diameter of the wave spring.

6. The method for using the permanent magnet electric drive assembly bearing chamber wave spring installation and fixing tool according to claim 1 is characterized in that: The positioning surface on the base is an outer stop surface, and the connecting parts are multiple glass ball screws arranged at different positions around the base, and each of the glass ball screws is radially installed on the outer stop surface.

7. The method for using the permanent magnet electric drive assembly bearing chamber wave spring installation and fixing tool according to claim 1 is characterized in that: The elastic claws are made of elastic steel structure, elastic plastic, or elastic nonferrous metal.

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