A claw pole hot forging and a finished claw pole manufacturing process based on the claw pole hot forging

Abstract

The present invention relates to the technical field of claw pole manufacturing, and in particular to a claw pole hot forging, in which the entire inner surface of the groove directly adopts a complete arc transition without a supporting plane part, and the steel shot used for subsequent shot blasting cannot be subjected to force and remain therein, and the stability of the manufacturing process is greatly improved; the present invention also provides a finished claw pole manufacturing process of the claw pole hot forging, and the key point is that the parts of the claw pole when the cold forming die is used to perform local cold finishing on the claw pole include the outer cylindrical surface of the yoke, the bottom plane, the inner inclined surface and the outer cylindrical surface of the claw pole, and do not include the magnet support surface and the magnet positioning surface; because the magnet support surface and the magnet positioning surface are not squeezed, no excess material flows into the groove reserved during forging, so no residual metal burrs will appear, and the stability of the manufacturing process is further improved.

Description

Technical Field

[0001] The invention relates to the technical field of claw pole manufacturing, in particular to a claw pole hot forging and a finished claw pole manufacturing process based on the claw pole hot forging. Background Art

[0002] The claw pole is the core component of the automobile AC generator rotor assembly. Its main function is to convert the axial magnetic field generated by the excitation coil in the rotor into a radial magnetic field, so that when the rotor rotates, an alternating magnetic field with a three-dimensional distribution in space is obtained. This alternating magnetic field moves relative to the stator to generate alternating current. Therefore, the claw pole of the automobile generator is sometimes also called the automobile generator magnetic pole.

[0003] The claw pole for hybrid excitation generator is a new type of claw pole structure based on the high-power and lightweight development of automobile AC generators. The difference from conventional claw poles is that magnet mounting grooves are left on both sides of the claw poles. Permanent magnets can be embedded in the magnet grooves during assembly and use, thereby greatly increasing the output power of the AC generator without increasing its volume.

[0004] Since the claw pole used in the hybrid excitation generator has a special structure of a magnet mounting groove compared to the conventional claw pole, in order to ensure the normal installation of the permanent magnet, there cannot be an arc with a radius greater than 0.5mm at the connection between the magnet positioning surface and the supporting surface of the magnet mounting groove. Such structural requirements require further improvements to the existing conventional claw pole manufacturing process to meet the needs of industrial production.

[0005] At present, there are three main manufacturing processes for claw poles for hybrid excitation generators, which are as follows:

[0006] (1) The processing technology of claw poles for hybrid excitation generators, the main process steps of this process method are hot forging blanks - magnetic annealing - cold finishing - drilling inner holes - precision boring inner control - turning the yoke end face - milling the magnet installation groove. The problem with this method is that the surface of the forging is not treated to remove the oxide scale on the surface of the claw pole hot forging before annealing and cold finishing. Direct cold finishing will cause problems such as mold damage and residual oxide scale pressing into the surface of the claw pole forging, affecting the performance of the claw pole. In addition, this method adds a milling process for the magnet installation groove, which greatly reduces the manufacturing efficiency of the claw pole and wastes materials and cutting tools.

[0007] (2) A hot forging and cold extrusion manufacturing process for claw poles for hybrid excitation generators, the main process steps of which are blanking-heating-forging-trimming-shot blasting-cold extrusion-drilling inner holes-finishing boring inner holes-turning yoke end faces. This method sets a material storage groove on the hot forging part, and uses hot forging and cold extrusion to manufacture the magnet mounting groove. There is no need for additional milling of the magnet mounting groove, which improves the manufacturing efficiency of the claw pole and saves materials and cutting tools. However, since this method sets a material storage groove and shot blasting process on the hot forging part, the steel shot particles from the shot blasting are easily left in the material storage groove during the actual manufacturing process, and the size fluctuation of the hot forging part will cause metal burrs that cannot completely fill the material storage groove during cold extrusion. The above problems all cause instability in the manufacturing process, which is not conducive to industrial production.

[0008] (3) Hot forgings of hybrid excitation motor claw poles and a method for manufacturing claw poles of hybrid excitation motors, the main process steps of this process method are hot forging blanks - heat treatment - shot blasting - shaping - phosphating - cold extrusion. This method realizes the manufacture of magnet mounting grooves by increasing the extrusion margin at the magnet groove part of the hot forging and combining surface lubrication methods such as phosphating by cold extrusion with large margin. Since the extrusion margin is large during cold forming, this process method needs to increase the surface phosphating, which causes greater pollution to the environment. In addition, since the margin is large during cold extrusion, the requirements for cold forming molds are increased. In addition, if this method is to obtain a complete claw pole product, it is also necessary to process the center hole used for the transfer of the rotor shaft. Summary of the invention

[0009] The technical problem to be solved by the present invention is to improve the stability of the existing hybrid excitation generator claw pole manufacturing process without polluting the environment and reducing the manufacturing efficiency.

[0010] In the first aspect, the present invention provides a claw pole hot forging, wherein the entire inner surface of the groove directly adopts a complete arc transition without a supporting plane part, and the steel shot used for subsequent shot blasting cannot be subjected to force and remain therein, and the stability of the manufacturing process is greatly improved. The specific technical scheme is as follows:

[0011] A claw hot forging, comprising:

[0012] Supporting part,

[0013] The claw pole finger assembly is a plurality of claw pole fingers distributed circumferentially along the center line.

[0014] The claw pole finger portion and the support portion are connected via the lower surface of the claw pole finger portion,

[0015] The claw pole finger portion includes an outer circular surface, an inner inclined surface, a magnet positioning surface and a magnet supporting surface.

[0016] A curved groove is arranged between the magnet supporting surface and the magnet positioning surface, and the entire inner surface of the curved groove is a complete curved arc structure.

[0017] Preferably, the arc radius of the curved arc structure is 0.5mm-1mm.

[0018] Preferably, the arc radius of the curved arc structure is 1 mm.

[0019] Preferably, the angle a between the magnet supporting surface and the magnet positioning surface of the hot forging is greater than 90°.

[0020] Preferably, the angle a between the magnet supporting surface and the magnet positioning surface of the hot forging is 91-93°.

[0021] Preferably, the angle a between the magnet supporting surface and the magnet positioning surface of the hot forging is 91.5°.

[0022] In the second aspect, the present invention provides a finished claw pole manufacturing process of a claw pole hot forging. The key point is that the parts of the claw pole that are locally cold finished by a cold forming die include the outer cylindrical surface of the yoke, the bottom plane, the inner inclined surface and the outer cylindrical surface of the claw pole, but do not include the magnet support surface and the magnet positioning surface; since the magnet support surface and the magnet positioning surface are not squeezed, no excess material flows into the groove reserved during forging, so there will be no residual metal burrs, and the stability of the manufacturing process is further improved. That is to say, the function of the groove set in the hot forging is not to accommodate material during cold extrusion, but only to ensure that there is no arc with a radius greater than 0.5 mm at the connection between the magnet positioning surface and the support surface of the magnet mounting groove of the final finished part, thereby avoiding interference during the assembly of the permanent magnet. The specific technical scheme is as follows:

[0023] 1) A hot die forging method is used to obtain a claw pole hot forging 01;

[0024] 2) performing post-forging treatment on the claw pole hot forging 01 to obtain a claw pole forged treated part, wherein the post-forging treatment is direct shot blasting treatment, or heat treatment and shot blasting treatment are performed in sequence;

[0025] 3) Then, the claw pole forging post-processing part 02 is subjected to local cold finishing by using a cold forming die to obtain a claw pole cold formed part 03, and the parts subjected to local cold finishing by using the cold forming die include the outer cylindrical surface of the yoke, the bottom plane, the inner inclined surface and the outer cylindrical surface of the claw pole;

[0026] 4) Finally, the claw pole cold-formed part 03 is partially cut to obtain a claw pole finished part 04, wherein the radius of the transition arc at the intersection of the magnet support surface and the magnet positioning surface of the claw pole finished part is not greater than 0.5 mm.

[0027] Preferably, the steps of the hot die forging method in step 1) are blanking-heating-pier blanking-pre-forging-final forging-trimming, wherein the blanking is performed by a sawing machine or a shearing machine, the heating is performed by medium frequency induction heating, the pier blanking, pre-forging and final forging processes are manufactured by a hot die forging machine, and the trimming is performed by a press for hot cutting or cold cutting to remove the forging flash.

[0028] Preferably, the local cutting process in step 4) is to process the center hole, the end face of the yoke, the outer cylindrical surface of the claw pole, the fan plane and the positioning keyway.

[0029] Preferably, the particle size of the steel shot during shot blasting is 0.8-1.2 mm, and the heat treatment is annealing or normalizing treatment of the hot forging.

[0030] The beneficial effects of the present invention are: the present invention is energy-saving and environmentally friendly, the entire manufacturing process does not involve a manufacturing process that pollutes the environment, the manufacturing efficiency is high, there is no need to mill the magnet installation groove, the manufacturing process is stable, the steel shot particles will not remain in the forging during the shot blasting process, and there will be no problem of residual metal burrs in the material storage tank after cold plastic forming. The specific beneficial effects are specifically manifested in the following aspects:

[0031] (1.1) The present invention provides a claw pole hot forging, in which the entire inner surface of the groove directly adopts a complete arc transition without a supporting plane part, and the steel shot used for subsequent shot blasting cannot be subjected to force and remain therein, and the stability of the manufacturing process is greatly improved;

[0032] (1.2) The arc radius of the curved arc structure is 0.5mm-1mm. If the arc radius is too small, it is not easy to forge. If the arc radius is too large, metal burrs that cannot completely fill the arc groove will appear during the subsequent cold finishing, affecting the stability of the manufacturing process. The appropriate arc radius ensures both easy forging and stability of the manufacturing process.

[0033] (1.3) The angle a between the magnet support surface and the magnet positioning surface of the hot forging is 91-93°. If the angle is too large, the deformation will be too large during the subsequent cold finishing. If the surface phosphosaponification treatment is not used, forming defects will easily occur and excessive material will form excess metal burrs. If the angle is too small, it will be difficult to put the hot forging into the cold finishing mold during cold finishing, which will not only affect the production efficiency but also reduce the life of the mold. The appropriate angle can simultaneously ensure the product manufacturing efficiency, the green environmental protection, the economy and stability of the manufacturing process.

[0034] (2.1) The present invention provides a finished claw pole manufacturing process for a claw pole hot forging. The key point is that the parts of the claw pole that are locally cold finished by a cold forming die include the outer cylindrical surface of the yoke, the bottom plane, the inner inclined surface and the outer cylindrical surface of the claw pole, but do not include the magnet support surface and the magnet positioning surface. Since the magnet support surface and the magnet positioning surface are not squeezed, no excess material flows into the groove reserved during forging, so there will be no residual metal burrs, and the stability of the manufacturing process is further improved. That is to say, the function of the groove set in the hot forging is not to accommodate material during cold extrusion, but only to ensure that there is no arc with a radius greater than 0.5 mm at the connection between the magnet positioning surface and the support surface of the magnet mounting groove of the final finished part, thereby avoiding interference during the assembly of the permanent magnet. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0036] Figure 1 A schematic diagram of the main structure of a claw pole hot forging obtained by the manufacturing process of the present invention;

[0037] Figure 2 Figure 1 AA section view;

[0038] Figure 3 Figure 2 BB section view of the claw pole finger;

[0039] Figure 4 A schematic diagram of the structure of a material storage tank for a claw hot forging in the prior art;

[0040] Figure 5 It is a schematic diagram of the structure of claw poles 01, 02 and 03;

[0041] Figure 6 It is a schematic diagram of the structure of the claw pole finished part 04.

[0042] In the figure: 1 magnet supporting surface, 2 magnet positioning surface, 3 curved groove of the present invention, 4 outer cylindrical surface of yoke, 5 bottom plane, 6 inner inclined surface, 7 outer cylindrical surface of claw pole, 8 middle hole, 9, end surface of yoke, 10 fan surface, 11 positioning key groove, 31 arc surface of material containing groove in the prior art, 32 residual plane of material containing groove in the prior art, 33 arc surface of material containing groove in the prior art. DETAILED DESCRIPTION

[0043] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0044] like Figure 5As shown, the shape and structure of the claw pole hot forging and the forged part are exactly the same, the difference lies in the presence of oxide scale and surface roughness; the shape and structure of the claw pole cold formed part and the forged part are different in the shape and precision of the shaped part, and the shaped part is bright;

[0045] like Figure 6 As shown, the hole structure in the claw pole finished part is different, which is the finished part model.

[0046] Example 1

[0047] A claw hot forging, characterized in that it includes:

[0048] Supporting part,

[0049] The claw pole finger assembly is a plurality of claw pole fingers distributed circumferentially along the center line.

[0050] The claw pole finger portion and the support portion are connected via the lower surface of the claw pole finger portion,

[0051] The claw pole finger portion includes an outer circular surface 7, an inner inclined surface 6, a magnet positioning surface 2 and a magnet supporting surface 1.

[0052] A curved groove 3 is arranged between the magnet supporting surface 1 and the magnet positioning surface 2, and the entire inner surface of the curved groove 3 is a complete curved arc structure.

[0053] In a specific implementation, the radius of the arc of the curved arc structure is 0.5 mm-1 mm.

[0054] In a specific implementation, the arc radius of the curved arc structure is 1 mm.

[0055] In a specific embodiment, the angle a between the magnet supporting surface 1 and the magnet positioning surface 2 of the hot forging is greater than 90°.

[0056] Preferably, the angle a between the magnet supporting surface 1 and the magnet positioning surface 2 of the hot forging is 91-93°.

[0057] Preferably, the angle a between the magnet supporting surface and the magnet positioning surface 2 of the hot forging is 91.5°.

[0058] The present invention provides a claw pole hot forging, wherein the entire inner surface of the groove directly adopts a complete arc transition without a supporting plane part, which is different from the existing material containing groove which is composed of two arc surfaces 31 and 33 and a plane 32. The arc radius of the curved arc structure of the present invention is 0.5mm-1mm, preferably 1mm. The entire inner surface of the groove directly adopts a complete arc transition without a supporting plane part, and the steel shots used for subsequent shot blasting cannot be subjected to force and remain therein, and the stability of the manufacturing process is greatly improved. The angle a between the magnet support surface 1 and the magnet positioning surface 2 of the hot forging is greater than 90°, preferably 91-93°, and further preferably 91.5°, so that during subsequent cold finishing, a gap is retained between the magnet support surface 1 and the cold forming mold while meeting the requirements of size and shape accuracy.

[0059] In the prior art, the groove structure was originally designed to facilitate material storage during cold extrusion, without considering the negative impact that the design of the groove structure would have on the manufacturing process. Therefore, a structure of any shape could be designed. Existing designers would not think of what shape structure is optimal for the manufacturing process. From the perspective of material storage, a flat surface on the inner surface of the groove makes it easier to judge the rationality of the deformation allowance setting through the residual metal from actual cold extrusion. Therefore, the earliest material storage grooves were all set with rectangular grooves and then the sharp corners of the rectangle were rounded to form a three-stage groove structure.

[0060] However, during the actual manufacturing process, we found that there were metal pellets left after shot blasting, so we considered optimizing the structure of the original groove with material storage function. After in-depth exploration, we finally found that the groove with a complete curved arc structure has the best comprehensive effect. Difficulties that need to be overcome in the technical solution of the present invention:

[0061] (1) Consider eliminating the material storage function of the forging groove to produce a claw pole product that meets the shape structure and dimensional accuracy requirements;

[0062] (2) Considering the groove structure is a factor affecting the stability of the manufacturing process;

[0063] (3) Considering the complete arc structure, the groove structure has the smallest supporting effect on the metal pellets;

[0064] (4) Consider the impact of the arc radius on the stability of the manufacturing process.

[0065] Example 2

[0066] The present invention provides a finished claw pole manufacturing process of a claw pole hot forging.

[0067] 1) The claw pole hot forging 01 is obtained by hot die forging, wherein the steps of the hot die forging method are blanking-heating-heading-pre-forging-final forging-trimming, wherein the blanking is performed by sawing machine or shearing machine, the heating is performed by medium frequency induction heating, the heading, pre-forging and final forging processes are manufactured by hot die forging machine, and the trimming is performed by hot cutting or cold cutting by press to remove forging flash;

[0068] 2) performing post-forging treatment on the claw pole hot forging 01 to obtain a claw pole forged treated part, wherein the post-forging treatment is direct shot blasting treatment, or heat treatment and shot blasting treatment are performed in sequence;

[0069] 3) Then, the claw pole forging post-processing part 02 is subjected to local cold finishing by using a cold forming die to obtain a claw pole cold formed part 03, and the parts subjected to local cold finishing by using the cold forming die include the outer cylindrical surface 4 of the yoke, the bottom plane 5, the inner inclined surface 6 and the outer cylindrical surface 7 of the claw pole;

[0070] 4) Finally, the claw pole cold-formed part 03 is locally cut to obtain the claw pole finished part 04. The radius of the transition arc at the intersection of the magnet support surface 1 and the magnet positioning surface 2 of the claw pole finished part is not more than 0.5 mm. The local cutting process includes processing the center hole 8, the yoke end face 9, the claw pole outer cylindrical surface 7, the fan plane 10 and the positioning keyway 11.

[0071] Embodiment 3:

[0072] (1) The hot die forging method specifically includes using a shearing machine or a sawing machine to cut the material to obtain a round steel billet of a certain length, then using a medium frequency induction heating furnace to heat the round steel billet to a suitable forging temperature, and using a hot die forging machine to perform hot forging forming processing on the heated round steel billet using a die, and the hot forging forming processing sequentially includes roughing, pre-forging, final forging and trimming. A curved groove 3 not used for material storage is set between the magnet support surface 1 and the magnet positioning surface 2 of the claw pole hot forging, and the entire groove inner surface of the curved groove 3 is a complete curved arc structure, which is different from the existing material storage groove consisting of two arc surfaces and a plane. The arc radius of the curved arc structure is 0.5mm-1mm, preferably 1mm. The entire groove inner surface of the curved groove 3 directly adopts a complete arc transition without a supporting plane part, and the steel shot used for subsequent shot blasting cannot be subjected to force and remains therein, and the stability of the manufacturing process is greatly improved. The angle a between the magnet support surface 1 and the magnet positioning surface 2 of the hot forging is greater than 90°, preferably 91-93°, and further preferably 91.5°, so that during subsequent cold finishing, a gap is retained between the magnet support surface 1 and the cold forming die while meeting the requirements of size and shape accuracy.

[0073] (2) Then, the claw pole hot forging 01 is subjected to post-forging treatment to obtain the claw pole forging treated part 02. The post-forging treatment specifically includes direct shot blasting treatment of the forging using a shot blasting machine to remove the oxide scale on the surface of the forging. The particle size of the steel shot during the shot blasting treatment is preferably 0.8-1.2 mm.

[0074] (3) Then, the claw pole forging processed part 02 is subjected to cold plastic forming by using a cold forming die to obtain a claw pole cold formed part 03. Specifically, the yoke outer cylindrical surface 4, the bottom plane 5, the inner inclined surface 6 and the claw pole outer cylindrical surface 7 of the claw pole forging processed part are cold finished to improve the size and shape and position accuracy of the corresponding parts.

[0075] (4) Finally, the claw pole cold-formed part 03 is cut to obtain the claw pole finished part 04. Specifically, the claw pole center hole 8, the fan surface 10, the claw pole outer cylindrical surface 7 and the yoke end surface 9 are machined by a machine tool to improve the size and shape and position accuracy of the corresponding parts of the claw pole.

[0076] Example 4

[0077] The method is basically the same as Example 3, except that: in step 2), the post-forging treatment is to firstly perform heat treatment on the claw pole in an annealing furnace to improve the magnetic conductivity of the claw pole, and then directly perform shot blasting on the forging in a shot blasting machine to remove the oxide scale on the surface of the forging.

[0078] Among them, cold finishing is an existing technology, which is to use cold finishing dies to perform small-allowance surface plastic deformation on forgings. Cold finishing and cold extrusion are both subordinate concepts of cold plastic deformation. The main difference lies in the size of the deformation allowance. The main function is to ensure the size and shape position accuracy of the local position of the claw pole. In the existing scheme, it is considered that the shape and position fluctuations of the hot forging magnet support surface and positioning surface exceed the requirements of the existing claw pole finished products, so these two surfaces are included in the cold plastic deformation.

[0079] In order to solve the problem of residual metal burrs in this scheme, cold plastic deformation is considered to use cold finishing, that is, to reduce the deformation during cold forming, so as to improve the stability of the manufacturing process while ensuring the shape position and dimensional accuracy of the local position of the product. The key to cold finishing lies in the control of the shaping position and shaping margin. This scheme is different from the prior art scheme in that the magnet support surface and the positioning surface are shaped. Instead, these two surfaces are completely avoided during shaping, and the shape and dimensional accuracy after shaping are controlled by the angle between the magnet mounting surface and the magnet positioning surface in the forging structure. After cold finishing, the angle between the magnet mounting surface and the magnet positioning surface should theoretically be 90°, and in fact a deviation of plus or minus 15' is allowed.

[0080] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A claw hot forging, characterized in that: include, Supporting part, The claw pole finger assembly is a plurality of claw pole fingers distributed circumferentially along the center line. The claw pole finger portion and the support portion are connected via the lower surface of the claw pole finger portion, The claw pole finger portion includes an outer circular surface, an inner inclined surface, a magnet positioning surface and a magnet supporting surface. A curved groove is arranged between the magnet supporting surface and the magnet positioning surface. The entire inner surface of the curved groove is a complete curved arc structure. The arc radius of the curved arc structure is 0.5mm-1mm.

2. A claw-type hot forging according to claim 1, characterized in that: The arc radius of the curved arc structure is 1 mm.

3. The claw-type hot forging according to claim 1, characterized in that: The angle a between the magnet supporting surface and the magnet positioning surface of the hot forging is greater than 90°.

4. A claw-type hot forging according to claim 3, characterized in that: The angle a between the magnet supporting surface and the magnet positioning surface of the hot forging is 91-93°.

5. A claw-type hot forging according to claim 4, characterized in that: The angle a between the magnet supporting surface and the magnet positioning surface of the hot forging is 91.5°.

6. A process for manufacturing a finished claw pole hot forged part according to any one of claims 1 to 5, characterized in that: 1) A hot die forging method is used to obtain a claw pole hot forging (01); 2) performing post-forging treatment on the claw pole hot forged part (01) to obtain a claw pole forged part, wherein the post-forging treatment is direct shot blasting treatment, or heat treatment and shot blasting treatment are performed in sequence; 3) Then, the claw pole forging post-processing part (02) is subjected to local cold finishing by using a cold forming die to obtain a claw pole cold formed part (03), wherein the parts subjected to local cold finishing by using the cold forming die include the outer cylindrical surface of the yoke, the bottom plane, the inner inclined surface and the outer cylindrical surface of the claw pole; 4) Finally, the claw pole cold-formed part (03) is partially cut to obtain a claw pole finished part (04), wherein the radius of the transition arc at the intersection of the magnet support surface and the magnet positioning surface of the claw pole finished part is not greater than 0.5 mm.

7. The process for manufacturing a finished claw pole of a claw pole hot forged part according to claim 6, characterized in that: Step 1) The hot die forging method comprises the following steps: blanking - heating - pier blank - pre-forging - final forging - trimming, wherein the blanking is performed by a sawing machine or a shearing machine, the heating is performed by medium frequency induction heating, the pier blank, pre-forging and final forging processes are performed by a hot die forging machine, and the trimming is performed by a press for hot cutting or cold cutting to remove the forging flash.

8. The process for manufacturing a finished claw pole of a claw pole hot forged part according to claim 6, characterized in that: The local cutting process in step 4) is to process the center hole, the end face of the yoke, the outer cylindrical surface of the claw pole, the fan plane and the positioning keyway.

9. The process for manufacturing a finished claw pole of a claw pole hot forged part according to claim 6, characterized in that: The particle size of the steel shot during shot blasting is 0.8-1.2 mm, and the heat treatment is annealing or normalizing of the hot forging.

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