Pump rotor assembly, oil pump and manufacturing method of oil pump

Abstract

The pump rotor assembly comprises a first rotor, the first rotor is an injection molding part, the position where injection molding materials are filled is defined, a feeding position of the first rotor is formed on the surface of the first rotor, the first rotor comprises reinforcing ribs, and the reinforcing ribs can improve the strength of the first rotor. The pump rotor assembly comprises a first rotor, the rotating shaft is connected with the first rotor, the first rotor is an injection molding part and comprises reinforcing ribs, the reinforcing ribs can improve the strength of the first rotor, and the invention further provides an oil pump and a manufacturing method of the oil pump.

Description

Technical Field

[0001] This application relates to the field of vehicles, and more particularly to oil pumps used in vehicles. Background Technology

[0002] Oil pumps are widely used in vehicle lubrication and / or cooling systems. They primarily provide power to these systems. Oil pumps come in various structural forms, such as rotary pumps and gear pumps. Taking a rotary pump as an example, it includes inner and outer rotors, a pump housing, and other components. Both the active inner rotor and the driven outer rotor are installed inside the pump housing. In related technologies, the inner rotor is made of plastic, but the strength of plastic inner rotors needs to be improved. Summary of the Invention

[0003] The technical problem to be solved by this application is to increase the strength of the inner rotor.

[0004] To solve the above-mentioned technical problems, this application provides a pump rotor assembly, including a first rotor and a second rotor. The first rotor includes a plurality of external teeth, and the second rotor includes a plurality of internal teeth. At least a portion of the external teeth mesh with at least a portion of the internal teeth, and the first rotor is capable of driving the second rotor to rotate.

[0005] The first rotor is an injection molded part, and the first rotor includes reinforcing ribs that extend from the first rotor away from the external teeth and protrude from the sidewall of the first rotor.

[0006] The pump rotor assembly provided in this application includes a first rotor, which is an injection molded part. The position for filling the injection molding material is defined by forming the inlet position of the first rotor on the surface of the first rotor. The first rotor includes reinforcing ribs, which can improve the strength of the first rotor.

[0007] This application also provides an oil pump, including a pump rotor assembly and a rotating shaft. The rotating shaft can drive the pump rotor assembly to rotate. The pump rotor assembly includes a first rotor and a second rotor. The first rotor includes a plurality of external teeth, and the second rotor includes a plurality of internal teeth. At least a portion of the external teeth meshes with at least a portion of the internal teeth. The rotating shaft is connected to the first rotor, and the first rotor can drive the second rotor to rotate.

[0008] The first rotor is an injection molded part. The first rotor includes a reinforcing rib. The rotating shaft is connected to the reinforcing rib. The reinforcing rib extends from the first rotor to the side away from the external teeth and protrudes from the side wall of the first rotor.

[0009] The oil pump provided in this application includes a pump rotor assembly and a rotating shaft. The pump rotor assembly includes a first rotor, and the rotating shaft is connected to the first rotor. The first rotor is an injection-molded part, and the first rotor includes reinforcing ribs, which can improve the strength of the first rotor.

[0010] This application also provides a method for manufacturing an oil pump, comprising providing a first mold having at least two first inlets, filling the first mold with a first injection molding material through the at least two first inlets, forming a first rotor of the oil pump within the first mold, and the first rotor including reinforcing ribs located between two adjacent inlets.

[0011] The method for manufacturing an oil pump provided in this application includes a first mold, in which a first rotor formed includes reinforcing ribs located between two adjacent feed ports, such that the reinforcing ribs can strengthen the first rotor located between the two adjacent feed ports. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the structure of a pump rotor assembly provided in one embodiment of this application;

[0014] Figure 2 for Figure 1 A schematic diagram of the structure of the first rotor in the middle;

[0015] Figure 3 for Figure 2 A top-down view;

[0016] Figure 4 for Figure 3 Schematic sectional view of section C in the middle;

[0017] Figure 5 for Figure 1 Schematic diagram of the structure of the second rotor;

[0018] Figure 6 for Figure 5 A top-down view;

[0019] Figure 7 for Figure 6 Schematic sectional view of section D;

[0020] Figure 8This is a schematic diagram of the structure of an oil pump provided in an embodiment of this application;

[0021] Figure 9 for Figure 8 Another structural diagram from a different perspective;

[0022] Figure 10 for Figure 8 A cross-sectional view;

[0023] Figure 11 for Figure 8 Exploded view of the rotor assembly and shaft of the medium-sized pump.

[0024] In the diagram: 11-First rotor; 11a-External teeth; 11b-Reinforcing rib; 11r-First rotor section A; 11s-First rotor section B; 11t-Melting section; 11u-First rotor section C; 111-First wall; 112-Second wall; 111b-First reinforcing rib wall; 112b-Second reinforcing rib wall; 113b-Third reinforcing rib wall; 11c-Cylinder section; 11d-First partition; 11e-Joint section; 110-Feeding position; 113-First A end wall; 114-First B end wall; 12-Second rotor; 12a-Internal teeth; 121a-Second A end Wall; 121b-Second B-end wall; 10-First hole group; 12d-Second partition; 10a-First A-hole; 10b-First B-hole; 20-Second hole group; 20a-Second A-hole; 20b-Second B-hole; L1-First rotating shaft; L2-Second rotating shaft; A-Pump rotor assembly; B-Shaft; B1-Groove; S-Weld line; 2-Stator assembly; 3-Motor rotor assembly; 4-Electrical control board; A1-First receiving cavity; A2-Second receiving cavity; 51-First housing; 52-Second housing; 53-Pump cover; 61-Inflow channel; 62-Outflow channel. Detailed Implementation

[0025] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. In the following description relating to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements.

[0026] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0027] It should be understood that the terms "first," "second," and similar terms used in this application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, "a" or "one," and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one; "multiple" indicates two or more. Unless otherwise stated, terms such as "front," "rear," "lower," and / or "upper" are for illustrative purposes only and are not limited to a location or spatial orientation. Terms such as "comprising" or "including" indicate that the elements or objects preceding "comprising" encompass the elements or objects listed following "comprising" or "including" and their equivalents, but do not exclude other elements or objects.

[0028] The exemplary embodiments of this application will now be described in detail with reference to the accompanying drawings. Unless otherwise specified, the features of the following embodiments and implementation methods can complement or combine with each other.

[0029] A pump rotor assembly according to this application includes a first rotor 11 and a second rotor 12. The first rotor 11 includes a plurality of external teeth 11a and the second rotor 12 includes a plurality of internal teeth 12a. At least a portion of the external teeth 11a meshes with at least a portion of the internal teeth 12a. The first rotor 11 can drive the second rotor 12 to rotate.

[0030] The first rotor 11 is an injection molded part. The first rotor 11 includes a reinforcing rib 11b, which extends from the first rotor 11 toward the side away from the external teeth 11a and protrudes from the side wall of the first rotor 11.

[0031] The pump rotor assembly provided in this application includes a first rotor 11, which is an injection molded part, and the first rotor 11 includes a reinforcing rib 11b. The reinforcing rib 11b can improve the local strength of the first rotor 11, thereby improving its overall strength.

[0032] A pump rotor assembly according to this application includes a first rotor 11 and a second rotor 12. The first rotor 11 includes a plurality of external teeth 11a and the second rotor 12 includes a plurality of internal teeth 12a. At least a portion of the external teeth 11a meshes with at least a portion of the internal teeth 12a. The first rotor 11 can drive the second rotor 12 to rotate.

[0033] The first rotor 11 is an injection molded part. The first rotor 11 includes a reinforcing rib 11b, which extends radially along the first rotor 11 and protrudes from the side wall of the first rotor 11 away from the second rotor 12. The position for filling the injection molding material is defined by forming a feed position 110 on the surface of the first rotor 11. At least two feed positions 110 are provided, and at least a portion of the reinforcing rib 11b is located between two adjacent feed positions 110.

[0034] The pump rotor assembly provided in this application includes a first rotor 11, which is an injection molded part. The position for filling the injection molded material is defined to form a feed position 110 on the surface of the first rotor 11. The first rotor 11 includes reinforcing ribs, and at least some of the reinforcing ribs 11b are located between two adjacent feed positions 110. The reinforcing ribs 11b can improve the strength of the first rotor 11 between two adjacent feed positions 110. The reinforcing ribs 11b can improve the local strength of the first rotor 11, thereby helping to improve its overall strength.

[0035] According to a specific embodiment of this application, please refer to Figure 1 A pump rotor assembly includes a first rotor 11 and a second rotor 12. The first rotor 11 includes a plurality of external teeth 11a, and the second rotor 12 includes a plurality of internal teeth 12a. At least some of the external teeth 11a mesh with at least some of the internal teeth 12a, and the first rotor 11 is capable of driving the second rotor 12 to rotate.

[0036] Typically, pump rotor assemblies are manufactured using powder metallurgy sintering and / or machining. The powder metallurgy process includes sintering, forming, and machining, involving numerous and complex steps. For these reasons, related technologies have led to the development of pump rotor assemblies made of plastic. Plastic pump rotor assemblies can be molded using injection molding, but the strength of plastic pump rotor assemblies needs to be improved.

[0037] In this embodiment, the first rotor 11 is an injection molded part. The first rotor 11 can be processed and formed by injection molding. It should be noted that the first rotor 11 can be processed and formed by injection molding, including other finishing processing methods after the first rotor 11 is injection molded, such as grinding, machining grooving, deburring and other processing methods.

[0038] In this embodiment, as Figure 1 , Figure 2 and Figure 3 As shown, the first rotor 11 includes a reinforcing rib 11b, which extends from the first rotor 11 toward the side away from the external teeth 11a and protrudes from the sidewall of the first rotor 11. In other words, the reinforcing rib 11b protrudes from the first rotor 11 toward the side away from the second rotor 12 from the sidewall of the first rotor 11. The reinforcing rib 11b can improve the local strength of the first rotor 11, thereby helping to improve its overall strength.

[0039] In this embodiment, the position where the injection molding material is filled is defined to form the feed position 110 of the first rotor 11 on the surface of the first rotor 11.

[0040] The injection mold can be filled with injection material through the injection mold inlet to form the first rotor 11 of this embodiment. The inlet corresponds to the inlet position 110 of this embodiment. That is, the inlet position 110 of this embodiment is the orthographic projection of the inlet on the surface of the first rotor 11.

[0041] In this embodiment, at least two feeding positions 110 are provided, and at least some of the reinforcing ribs 11b are located between two adjacent feeding positions 110.

[0042] In this embodiment, the material inlet 110 is provided at least two times. In other words, the injection mold forming the first rotor 11 of this embodiment has at least two inlets, and the injection material can be filled into the injection mold through at least two inlets.

[0043] This embodiment is described using the example of a first rotor 11 having three feed positions 110 on its surface. Figure 1 , Figure 2 and Figure 3 As shown, three feed points 110 are evenly distributed along the circumference of the first rotor 11 on the surface of the first rotor 11 to improve the feed / glue balance of the first rotor 11 during injection molding. In other words, the injection mold forming the first rotor 11 of this embodiment has three feed ports.

[0044] like Figure 1 , Figure 2 and Figure 3 As shown, this embodiment takes three reinforcing ribs 11b as an example for description. The three reinforcing ribs 11b are respectively located between two adjacent feed positions 110, thereby improving the strength of the first rotor 11 between the two adjacent feed positions 110. The reinforcing ribs 11b can improve the local strength of the first rotor 11, thereby helping to improve its overall strength.

[0045] During the process of forming the first rotor 11, the injection material filled into the injection mold through the injection mold inlet flows along the circumference of the first rotor 11 from the inlet / inlet position 110 to a direction away from the inlet / inlet position 110. The injection materials injected from the three inlets will eventually contact and form the first rotor 11 as a whole.

[0046] The injection molding materials entering from the three inlets are defined as the first injection molding material, the second injection molding material, and the third injection molding material. In this embodiment, the first injection molding material, the second injection molding material, and the third injection molding material are made of the same material. The first injection molding material and the second injection molding material contact and fuse at the first weld surface, the second injection molding material and the third injection molding material contact and fuse at the second weld surface, and the first injection molding material and the third injection molding material contact and fuse at the third weld surface.

[0047] The first rotor 11 has relatively low strength at the first welded surface, the second welded surface and the third welded surface. Therefore, the first rotor 11 is prone to breakage at the first welded surface, the second welded surface and the third welded surface, which affects the service life of the first rotor 11.

[0048] Of course, in some other embodiments, the feed point 110 may be set to a single one, that is, if the injection mold has a single feed port, the weld surface is formed at the furthest point from the feed point 110.

[0049] The first rotor 11 includes a first rotor A segment 11r, a first rotor B segment 11s, and a molten section 11t. The molten section 11t is located between the first rotor A segment 11r and the first rotor B segment 11s. The molten section 11t connects the first rotor A segment 11r and the first rotor B segment 11s. The first rotor A segment 11r and the first rotor B segment 11s are joined at the molten section 11t to form an integral first rotor 11. The reinforcing rib 11b is located in the molten section 11t.

[0050] In this embodiment, the surface of the first rotor 11 has a weld line S. The injection molding material is joined at the weld line S to form an integral first rotor 11. The weld line S is located in the molten part 11t, and the weld surface is located in the molten part 11t. In other words, in this embodiment, the first rotor 11 includes a first rotor A segment 11r, a first rotor B segment 11s, and a first rotor C segment 11u. The first rotor A segment 11r and the first rotor B segment 11s are joined at the first weld surface / molten part 11t, the first rotor B segment 11s and the first rotor C segment 11u are joined at the second weld surface / molten part 11t, and the first rotor A segment 11r and the first rotor C segment 11u are joined at the third weld surface / molten part 11t. The weld line S is a line formed by the first weld surface, the second weld surface, and the third weld surface on the surface of the first rotor 11. In this embodiment, the weld line S is difficult to identify with the naked eye, but the weld line S in the microscopic state of the first rotor 11 can be displayed with the help of a microscopic image display instrument. In this embodiment, the molten part 11t is provided in three places.

[0051] In this embodiment, the surface of the first rotor 11 has three weld lines S, which are defined as the first weld line, the second weld line, and the third weld line. The first rotor 11 has a first wall 111 and a second wall 112 arranged radially along the first rotor 11. The first wall 111 is closer to the rotation axis of the first rotor 11 than the second wall 112. The first weld surface has the first weld line on the first wall 111, the second weld surface has the second weld line on the first wall 111, and the third weld surface has the third weld line on the first wall 111. The first rotor 11 is prone to breakage at the first weld line, the second weld line, and the third weld line, which affects the service life of the first rotor 11.

[0052] Of course, in some other embodiments, the reinforcing ribs, the feed position of the first rotor 11, and the weld line of the first rotor may be set to other quantities.

[0053] In this embodiment, the reinforcing rib 11b is located at the fusion line S. In other words, the reinforcing rib 11b at least partially covers the fusion line S. The reinforcing rib 11b can improve the connection strength of the first rotor 11 at the first fusion line, the second fusion line and the third fusion line. The reinforcing rib 11b can improve the local strength of the first rotor 11, thereby helping to improve its overall strength.

[0054] The first rotor 11 includes a cylindrical portion 11c, and the external teeth 11a are integral with the cylindrical portion 11c. That is, the external teeth 11a and the cylindrical portion 11c can be integrally injection molded. The external teeth 11a are located on the side of the cylindrical portion 11c away from the first rotation axis L1 of the first rotor 11. The reinforcing ribs 11b are located on the inner sidewall of the cylindrical portion 11c to avoid affecting the engagement and transmission between the external teeth 11a of the first rotor 11 and the internal teeth 12a of the second rotor 12.

[0055] In this embodiment, the first wall 111 is the inner wall of the cylindrical portion 11c. The reinforcing rib 11b and the cylindrical portion 11c are integral parts, and the cylindrical portion 11c and the reinforcing rib 11b can be integrally injection molded.

[0056] The feed point 110 is defined as the starting point for the injection molding material to form the first rotor 11, and the weld line S is defined as the ending point for the injection molding material to form the first rotor 11. In other words, during the injection molding process of the first rotor 11, the liquid injection molding material forming the first rotor 11 flows from the feed point 110 to the weld line S along the circumference of the first rotor 11, and is joined at the weld line S to form an integral first rotor 11.

[0057] It should be noted that the fusion line S is a virtual line defined on the surface of the first rotor 11. In the actual product, the fusion line S is difficult to see with the naked eye. However, the fusion line S in the microscopic state of the first rotor 11 can be observed with the help of instruments.

[0058] The fusion line S is a straight line or a roughly straight line.

[0059] In this embodiment, the connection between the external tooth 11a and the cylindrical portion 11c is defined as the joint portion 11e. The joint portion 11e is located between the external tooth 11a and the cylindrical portion 11c. The joint portion 11e connects the external tooth 11a and the cylindrical portion 11c. The joint portion 11e, the external tooth 11a, and the cylindrical portion 11c are integral parts. The joint portion 11e, the external tooth 11a, and the cylindrical portion 11c can be integrally injection molded.

[0060] Along the radial direction of the first rotor 11, the reinforcing rib 11b and the joint 11e are located on the inner and outer arcuate walls of the cylindrical part 11c, respectively. By utilizing the designed reinforcing rib 11b and joint 11e, the reinforcing rib 11b can improve the local strength of the first rotor 11, thereby helping to improve its overall strength.

[0061] In this embodiment, six joint portions 11d are provided, such as... Figure 3 As shown, the six joints 11e are evenly distributed along the circumference of the cylindrical portion 11c, and two of the joints 11e and the reinforcing rib 11b are located in the same diametrical direction as the first rotor 11.

[0062] Of course, in some other embodiments, the number of joints 11e may be the same as the number of reinforcing ribs 11b.

[0063] At least two reinforcing ribs 11b are provided, and the two reinforcing ribs 11b are evenly distributed on the inner arc-shaped wall of the cylinder 11c. This embodiment is described using three reinforcing ribs 11b as an example. Figure 1 , Figure 2 and Figure 3 As shown, three reinforcing ribs 11b are evenly arranged on the inner arc-shaped wall / first wall of the cylinder 11c.

[0064] In this embodiment, the first rotor 11 has a first A-end wall 113 and a first B-end wall 114, which are arranged along the first rotation axis L1 of the first rotor 11, as shown below. Figure 4 As shown;

[0065] like Figure 4 As shown, the first rotor 11 has a first A hole 10a and a first B hole 10b. The first A hole 10a is located on the first A end wall 113, and the first B hole 10b is located on the first B end wall 114. The first rotor 11 includes a first partition 11d, which isolates the first A hole 10a and the first B hole 10b; that is, the first A hole 10a and the first B hole 10b are not connected.

[0066] In other words, the first A hole 10a penetrates the first A end wall 113 but does not penetrate the first B end wall 114; the first B hole 10b penetrates the first B end wall 114 but does not penetrate the first A end wall 113.

[0067] In this embodiment, the first A hole 10a and the first B hole 10b are arranged along the first rotation axis L1 of the first rotor 11, and the first A hole 10a is evenly distributed on the first A end wall 113 of the first rotor 11, and the first B hole 10b is evenly distributed on the first B end wall 114 of the first rotor 11. The first A hole 10a is located between the outer tooth 11a and the cylindrical part 11c, and the first B hole 10b is located between the outer tooth 11a and the cylindrical part 11c.

[0068] The first A hole 10a and the first B hole 10b are beneficial for the first rotor 11 to have a uniform wall thickness after injection molding, and can reduce the weight of the first rotor 11 and reduce the cost of the pump rotor assembly.

[0069] The first partition 11d is located between the external teeth 11a and the cylindrical portion 11c. The first partition 11d, the external teeth 11a, and the cylindrical portion 11c are integral parts and can be integrally injection molded. The first partition 11d is used to isolate the first A hole 10a and the first B hole 10b, making them non-connected. In addition, the first partition 11d can improve the strength of the first rotor 11.

[0070] In this embodiment, the second rotor 12 is an injection molded part. The second rotor 12 can be processed and formed by injection molding. It should be noted that the second rotor 12 can be processed and formed by injection molding, including other finishing processing methods after the second rotor 12 is injection molded, such as grinding, machining grooving, deburring and other processing methods.

[0071] In this embodiment, the first rotor 11 of the injection molded part can achieve lightweighting of the pump rotor assembly and simplification of the molding process.

[0072] In this embodiment, the second rotor 12 of the injection molded part can achieve lightweighting of the pump rotor assembly and simplification of the molding process.

[0073] Please combine Figure 5 , Figure 6 and Figure 7 In the structure shown, in this embodiment, the second rotor 12 has a second A end face 121a and a second B end face 121b, and the second A end face 121a and the second B end face 121b are arranged along the second rotation axis L2 direction of the second rotor 12.

[0074] The second rotor 12 has a second A hole 20a and a second B hole 20b. The second A hole 20a is located on the second A end face 121a, and the second B hole 20b is located on the second B end face 121b. The second rotor 12 includes a second partition 12d, which isolates the second A hole 20a and the second B hole 20b, that is, the second A hole 20a and the second B hole 20b are not connected.

[0075] In other words, the second A hole 20a penetrates the second A end wall 121a but does not penetrate the second B end wall 121b; the second B hole 20b penetrates the second B end wall 121b but does not penetrate the second A end wall 121a.

[0076] In this embodiment, the second A hole 20a and the second B hole 20b are arranged along the second rotation axis L2 of the second rotor 12, and the second A hole 20a is evenly distributed on the second A end wall 121a of the second rotor 12, and the second B hole 20b is evenly distributed on the second B end wall 121b of the second rotor 12.

[0077] The second A hole 20a and the second B hole 20b are beneficial for the first rotor 11 to have a uniform wall thickness after injection molding, and can reduce the weight of the first rotor 11 and reduce the cost of the pump rotor assembly.

[0078] The second partition 12d and the internal gear 12a are integral parts, and the second partition 12d and the internal gear 12a can be integrally injection molded. The second partition 12d is used to isolate the second A hole 20a and the second B hole 20b so that the two are not connected. In addition, the second partition 12d can improve the strength of the first rotor 11.

[0079] The first rotor 11 and the second rotor 12 are eccentrically positioned.

[0080] The pump rotor assembly of this embodiment can be applied to oil pumps, especially oil pumps in vehicles.

[0081] This application also provides an oil pump, which includes a pump rotor assembly A and a rotating shaft B. The rotating shaft B can drive the pump rotor assembly A to rotate. The pump rotor assembly A includes a first rotor 11 and a second rotor 12. The first rotor 11 includes a plurality of external teeth 11a, and the second rotor 12 includes a plurality of internal teeth 12a. At least some of the external teeth 11a mesh with at least some of the internal teeth 12a. The rotating shaft B is connected to the first rotor 11, and the first rotor 11 can drive the second rotor 12 to rotate.

[0082] The first rotor 11 is an injection molded part. The first rotor 11 includes a reinforcing rib 11b. The rotating shaft B is connected to the reinforcing rib 11b. The reinforcing rib 11b extends from the first rotor 11 to the side away from the external teeth 11a and protrudes from the side wall of the first rotor 11.

[0083] The oil pump provided in this application includes a pump rotor assembly A and a rotating shaft B. The pump rotor assembly A includes a first rotor 11, and the rotating shaft B is connected to the first rotor 11. The first rotor 11 is an injection molded part, and the first rotor 11 includes a reinforcing rib 11b. The reinforcing rib 11b can improve the local strength of the first rotor 11, thereby improving its overall strength.

[0084] According to a specific embodiment of this application, please refer to Figure 11An oil pump includes a pump rotor assembly A and a shaft B. The shaft B is capable of driving the pump rotor assembly A to rotate. The pump rotor assembly A includes a first rotor 11 and a second rotor 12. The first rotor 11 includes a plurality of external teeth 11a, and the second rotor 12 includes a plurality of internal teeth. At least some of the external teeth 11a mesh with at least some of the internal teeth. The shaft B is connected to the first rotor 11, and the first rotor 11 is capable of driving the second rotor 12 to rotate.

[0085] In this embodiment, the first rotor 11 is an injection molded part. The first rotor 11 can be processed and formed by injection molding. It should be noted that the first rotor 11 can be processed and formed by injection molding, including other finishing processing methods after the first rotor 11 is injection molded, such as grinding, machining grooving, deburring and other processing methods.

[0086] like Figure 11 As shown, the first rotor 11 includes a reinforcing rib 11b. The reinforcing rib 11b extends from the first rotor 11 toward the side away from the external tooth 11a and protrudes from the side wall of the first rotor 11. In other words, the reinforcing rib 11b protrudes from the first rotor 11 toward the side away from the second rotor 12 and protrudes from the side wall of the first rotor 11. The reinforcing rib 11b can improve the local strength of the first rotor 11, thereby helping to improve its overall strength.

[0087] The position for injecting the molding material is defined to form the feed position 110 of the first rotor 11 on the surface of the first rotor 11. The first rotor 11 includes reinforcing ribs, and at least some of the reinforcing ribs 11b are located between two adjacent feed positions 110. The reinforcing ribs 11b can improve the strength of the first rotor 11 between two adjacent feed positions 110. The reinforcing ribs 11b can improve the local strength of the first rotor 11, thereby helping to improve its overall strength.

[0088] The injection mold can be filled with injection material through the injection mold inlet to form the first rotor 11 of this embodiment. The inlet corresponds to the inlet position 110 of this embodiment. That is, the inlet position 110 of this embodiment is the orthographic projection of the inlet on the surface of the first rotor 11.

[0089] There are at least two feeding positions 110, and at least some of the reinforcing ribs 11b are located between two adjacent feeding positions 110.

[0090] In this embodiment, the material inlet 110 is provided at least two times. In other words, the injection mold forming the first rotor 11 of this embodiment has at least two inlets, and the injection material can be filled into the injection mold through at least two inlets.

[0091] This embodiment is described using the example of a first rotor 11 having three feed positions 110 on its surface. Figure 11As shown, three feed points 110 are evenly distributed along the circumference of the first rotor 11 on the surface of the first rotor 11 to improve the feed / glue balance of the first rotor 11 during injection molding. In other words, the injection mold forming the first rotor 11 of this embodiment has three feed ports.

[0092] like Figure 11 As shown, this embodiment takes three reinforcing ribs 11b as an example for description. The three reinforcing ribs 11b are respectively located between two adjacent feed positions 110, thereby improving the strength of the first rotor 11 between the two adjacent feed positions 110. The reinforcing ribs 11b can improve the local strength of the first rotor 11, thereby helping to improve its overall strength.

[0093] During the process of forming the first rotor 11, the injection material filled into the injection mold through the injection mold inlet flows along the circumference of the first rotor 11 from the inlet / inlet position 110 to a direction away from the inlet / inlet position 110. The injection materials injected from the three inlets will eventually contact and form the first rotor 11 as a whole.

[0094] The injection molding materials entering from the three inlets are defined as the first injection molding material, the second injection molding material, and the third injection molding material. In this embodiment, the first injection molding material, the second injection molding material, and the third injection molding material are made of the same material. The first injection molding material and the second injection molding material contact and fuse at the first weld surface, the second injection molding material and the third injection molding material contact and fuse at the second weld surface, and the first injection molding material and the third injection molding material contact and fuse at the third weld surface.

[0095] The first rotor 11 has relatively low strength at the first welded surface, the second welded surface and the third welded surface. Therefore, the first rotor 11 is prone to breakage at the first welded surface, the second welded surface and the third welded surface, which affects the service life of the first rotor 11.

[0096] The first rotor 11 includes a first rotor A segment 11r, a first rotor B segment 11s, and a molten section 11t. The molten section 11t is located between the first rotor A segment 11r and the first rotor B segment 11s. The molten section 11t connects the first rotor A segment 11r and the first rotor B segment 11s. The first rotor A segment 11r and the first rotor B segment 11s are joined at the molten section 11t to form an integral first rotor 11. The reinforcing rib 11b is located in the molten section 11t.

[0097] In this embodiment, the surface of the first rotor 11 has a weld line S, which is located in the molten portion 11t, and the weld surface is located in the molten portion 11t. The injection molding material is joined at the weld line S to form an integral first rotor 11. In other words, in this embodiment, the first rotor 11 includes a first rotor A segment 11r, a first rotor B segment 11s, and a first rotor C segment 11u. The first rotor A segment 11r and the first rotor B segment 11s are joined at the first weld surface / molten portion 11t, and the first rotor B segment 11s and the first rotor C segment 11u are joined at the second weld surface / molten portion 11t. A rotor segment A 11r and a first rotor segment C 11u are joined at the third welding surface / melting part 11t. The weld line S is a line formed by the first welding surface, the second welding surface, and the third welding surface on the surface of the first rotor 11. In this embodiment, the weld line S is difficult to identify with the naked eye, but it can be displayed in the microscopic state of the first rotor 11 using an image microscopic display instrument. In this embodiment, the melting part 11t is provided in three places. In other words, the surface of the first rotor 11 in this embodiment has three weld lines S. The three weld lines S are defined as the first weld line, the second weld line, and the third weld line, as follows: Figure 11 Taking one of the weld lines S as an example, the first rotor 11 has a first wall 111 and a second wall 112 arranged radially along the first rotor 11. The first wall 111 is closer to the rotation axis of the first rotor 11 than the second wall 112. The first weld surface has a first weld line on the first wall 111, the second weld surface has a second weld line on the first wall 111, and the third weld surface has a third weld line on the first wall 111. The first rotor 11 is prone to breakage at the first weld line, the second weld line and the third weld line, which affects the service life of the first rotor 11.

[0098] Of course, in some other embodiments, the reinforcing ribs, the feed position of the first rotor 11, and the weld line of the first rotor may be set to other quantities.

[0099] In this embodiment, the reinforcing rib 11b is located at the fusion line S. In other words, the reinforcing rib 11b at least partially covers the fusion line S. The reinforcing rib 11b can improve the connection strength of the first rotor 11 at the first fusion line, the second fusion line and the third fusion line, thereby improving the strength of the first rotor 11.

[0100] The first rotor 11 includes a cylindrical portion 11c, and the external teeth 11a are integral with the cylindrical portion 11c. That is, the external teeth 11a and the cylindrical portion 11c can be integrally injection molded. The external teeth 11a are located on the side of the cylindrical portion 11c away from the first rotation axis L1 of the first rotor 11. The reinforcing ribs 11b are located on the inner sidewall of the cylindrical portion 11c to avoid affecting the engagement and transmission between the external teeth 11a of the first rotor 11 and the internal teeth 12a of the second rotor 12.

[0101] In this embodiment, the first wall 111 is the inner wall of the cylindrical portion 11c, and the weld line S is located on the inner wall of the cylindrical portion 11c. The second wall 112 is the outer wall of the cylindrical portion 11c. The reinforcing rib 11b is integral with the cylindrical portion 11c, and the cylindrical portion 11c and the reinforcing rib 11b can be integrally injection molded.

[0102] The feed point 110 is defined as the starting point for the injection molding material to form the first rotor 11, and the weld line S is defined as the ending point for the injection molding material to form the first rotor 11. In other words, during the injection molding process of the first rotor 11, the liquid injection molding material forming the first rotor 11 flows from the feed point 110 to the weld line S along the circumference of the first rotor 11, and is joined at the weld line S to form an integral first rotor 11.

[0103] It should be noted that the fusion line S is a virtual line defined on the surface of the first rotor 11. In the actual product, the fusion line S is difficult to see with the naked eye. However, the fusion line S in the microscopic state of the first rotor 11 can be observed with the help of instruments.

[0104] The fusion line S is a straight line or a roughly straight line.

[0105] In this embodiment, the connection between the external tooth 11a and the cylindrical portion 11c is defined as the joint portion 11e, such as... Figure 11 As shown, the joint 11e is located between the outer tooth 11a and the cylindrical part 11c. The joint 11e connects the outer tooth 11a and the cylindrical part 11c. The joint 11e, the outer tooth 11a and the cylindrical part 11c are an integral part. The joint 11e, the outer tooth 11a and the cylindrical part 11c can be integrally injection molded.

[0106] Along the radial direction of the first rotor 11, the reinforcing rib 11b and the joint 11e are located on the inner and outer arcuate walls of the cylindrical part 11c, respectively. By utilizing the designed reinforcing rib 11b and joint 11e, the strength of the first rotor 11 can be improved.

[0107] In this embodiment, six joint portions 11d are provided, such as... Figure 11 As shown, the six joints 11e are evenly distributed along the circumference of the cylindrical portion 11c, and two of the joints 11e and the reinforcing rib 11b are located in the same diametrical direction as the first rotor 11.

[0108] Of course, in some other embodiments, the number of joints 11e may be the same as the number of reinforcing ribs 11b.

[0109] In this embodiment, as Figure 11 As shown, the rotating shaft B has a groove B1 that extends radially along the rotating shaft B and is recessed into the outer wall of the rotating shaft B. The reinforcing rib 11b is at least partially located in the groove B1 to improve the connection stability between the rotating shaft B and the first rotor 11.

[0110] The reinforcing rib 11b is set as a rectangular or roughly rectangular structure; the rotating shaft B is connected to the reinforcing rib 11b with an interference fit.

[0111] In this embodiment, as Figure 11 As shown, the reinforcing rib 11b includes a first reinforcing rib wall 111b, a second reinforcing rib wall 112b, and a third reinforcing rib wall 113b. The second reinforcing rib wall 112b connects the first reinforcing rib wall 111b and the third reinforcing rib wall 113b. At least one of the first reinforcing rib wall 111b, the second reinforcing rib wall 112b, and the third reinforcing rib wall 113b is interference-fitted with the wall forming the groove B1. Through the above design, the contact area between the reinforcing rib 11b and the rotating shaft B can be increased, and the connection stability between the reinforcing rib 11b and the rotating shaft B is better. In addition, the first reinforcing rib wall 111b, the second reinforcing rib wall 112b, and the third reinforcing rib wall 113b can disperse the force exerted by the rotating shaft B on the reinforcing rib 11b, thereby effectively alleviating the problem of force concentration on the reinforcing rib 11b at the weld line S, so as to improve the service life of the reinforcing rib 11b and even the first rotor 11.

[0112] In this embodiment, the first rotor 11 has a plurality of first hole groups 10, which are evenly distributed along the circumference of the first rotor 11. The first hole group 10 includes a first A hole 10a and a first B hole. The first A hole 10a and the first B hole extend discontinuously along the first rotation axis L1 of the first rotor 11, that is, the first A hole 10a and the first B hole are not connected.

[0113] In this embodiment, the first A hole 10a and the first B hole 10b are arranged along the first rotation axis L1 of the first rotor 11. The first A hole 10a is located between the external tooth 11a and the cylindrical portion 11c, and the first B hole 10b is located between the external tooth 11a and the cylindrical portion 11c. The first A hole 10a and the first B hole 10b are beneficial for the first rotor 11 to have a uniform wall thickness after injection molding, and can reduce the weight of the first rotor 11 and reduce the cost of the pump rotor assembly.

[0114] The first rotor 11 includes a first partition plate located between the first A hole 10a and the first B hole 10b. The first partition plate, the external teeth 11a, and the cylindrical portion 11c are integrally formed and can be integrally injection molded. The first partition plate is used to isolate the first A hole 10a and the first B hole 10b, making them non-connected. In addition, the first partition plate can improve the strength of the first rotor 11.

[0115] Since the first rotor 11 is an injection molded part, the liquid injection molded part will shrink after solidification. The presence of the first partition 11d will cause the first rotor 11 to shrink at different rates than other places where the first partition is designed. In other words, the first partition will affect the overall profile of the outer teeth 11a of the first rotor 11.

[0116] In this embodiment, the wall thickness of the external tooth 11a is defined as D1, and the wall thickness of the first partition is defined as D2, with 0.4*D1≤D2≤0.7*D1, so as to reduce the influence of the first partition on the overall profile of the external tooth 11a, that is, the first partition has a smaller impact on the overall tooth shape of the external tooth 11a.

[0117] The second rotor 12 is an injection-molded part. The second rotor 12 has multiple second hole groups 20, which are evenly distributed circumferentially along the second rotor 12. Each second hole group 20 includes a second A hole 20a and a second B hole 20b. The second A hole 20a and the second B hole 20b extend discontinuously along the second rotation axis L2 of the second rotor 12; that is, the second A hole 20a and the second B hole 20b are not connected. Figure 10 As shown, the second A hole 20a and the second B hole 20b are beneficial for the second rotor 12 to have a uniform wall thickness after injection molding, and can reduce the weight of the second rotor 12 and reduce the cost of the pump rotor assembly.

[0118] The second rotor 12 includes a second partition 12d, which is located between the second A hole 20a and the second B hole 20b. The second partition 12d and the internal gear 12a are integrally formed and can be integrally injection molded. The second partition 12d is used to isolate the second A hole 20a and the second B hole 20b, making them non-connected. In addition, the second partition 12d can improve the strength of the second rotor 12.

[0119] Since the second rotor 12 is an injection molded part, the liquid injection molded part will shrink after solidification. The presence of the second partition 12d will cause the second rotor 12 to shrink at different rates than other places where the second partition 12d is designed. In other words, the first partition will affect the overall profile of the internal teeth 12a of the second rotor 12.

[0120] In this embodiment, the wall thickness of the internal tooth 12a is defined as D3, and the wall thickness of the second partition 12d is defined as D4, with 0.4*D3≤D4≤0.7*D3, in order to reduce the influence of the second partition 12d on the overall profile of the internal tooth 12a. That is, the second partition 12d has a smaller impact on the overall tooth shape of the internal tooth 12a.

[0121] In this embodiment, the oil pump includes a pump housing, a stator assembly 2, a motor rotor assembly 3, and an electronic control board 4. The pump rotor assembly A, the motor rotor assembly 3, and the electronic control board 4 are arranged along the axial direction of the oil pump. The motor rotor assembly 3 is located between the pump rotor assembly A and the electronic control board 4. The stator assembly 2 is located on the outer periphery of the motor rotor assembly 3. The motor rotor assembly 3 drives the pump rotor assembly A to rotate through the rotating shaft B.

[0122] The oil pump also includes a first receiving cavity A1 and a second receiving cavity A2. The pump rotor assembly A is located in the first receiving cavity A1, and the stator assembly 2 and the motor rotor assembly 3 are located in the second receiving cavity A2. Figure 10 As shown.

[0123] During the operation of the oil pump, the electronic control board 4 controls the stator assembly 2 to change the excitation magnetic field. The motor rotor assembly 3 rotates under the action of the excitation magnetic field. The motor rotor assembly 3 can directly or indirectly drive the pump rotor assembly A to rotate. When the pump rotor assembly A rotates, the volume of the cavity between the pump rotor assemblies A changes, thereby causing the working medium to be forced out to... Figure 9 The outflow channel 62 is shown.

[0124] like Figure 8 , Figure 9 and Figure 10 As shown, the pump housing includes a first housing 51, a second housing 52, and a pump cover 53. The pump cover 53 is connected to the first housing 51 by screws or bolts, and the first housing 51 and the second housing 52 are connected by screws or bolts. Specifically, as shown... Figure 8 and Figure 10 As shown, a spacer 54 is provided between the first housing 51 and the second housing 52, and screws or bolts pass through the second housing 52, the spacer 54 and the first housing 51 in sequence.

[0125] The electronic control board 4 is located in the cavity between the first housing 51 and the isolation member 54, which facilitates the maintenance of the electronic control board 4.

[0126] In this embodiment, there is a certain eccentricity between the first rotor 11 and the second rotor 12 of the pump rotor assembly A. At least a portion of the external teeth 11a of the first rotor 11 meshes with at least a portion of the internal teeth 12a of the second rotor 12, thereby enabling the first rotor 11 to drive the second rotor 12 to rotate.

[0127] In this embodiment, the oil pump has an inflow channel 61 and an outflow channel 62. Please refer to... Figure 8 and Figure 9As shown, the inflow channel 61 is used for the inflow of the working medium, and the outflow channel 62 is used for the outflow of the working medium. Specifically, the working medium can enter the volume cavity between the first rotor 11 and the second rotor 12 through the inflow channel 61, and the working medium can leave the volume cavity between the first rotor 11 and the second rotor 12 through the outflow channel 62. In this embodiment, both the inflow channel 61 and the outflow channel 62 are formed on the pump cover 53.

[0128] Of course, in some other embodiments, when the oil pump does not include the pump cover 53, other components besides the pump cover 53 can be directly assembled with the vehicle's transmission. In this case, the inflow channel 61 and the outflow channel 62 can be correspondingly set on the transmission.

[0129] During one revolution of the pump rotor assembly A, the volume of the cavity formed between at least one external tooth 11a of the first rotor 11 and the internal tooth 12a of the second rotor 12 corresponding to the external tooth 11a will change. Specifically, as the pump rotor assembly A rotates from the starting point to a certain angle, the volume of the cavity formed between at least one external tooth 11a of the first rotor 11 and the internal tooth 12a of the second rotor 12 corresponding to the external tooth 11a will gradually increase, thereby forming a partial vacuum. At this time, the working medium is drawn into the cavity from the inflow channel 61. As the first rotor 11 and the second rotor 12 continue to rotate, the volume of the cavity formed between at least one external tooth 11a of the first rotor 11 and the internal tooth 12a of the second rotor 12 corresponding to the external tooth 11a will gradually decrease. The working medium is squeezed, causing the working medium entering the cavity to be forced out to the outflow channel 62, thereby generating the flow power.

[0130] This application also provides a method for manufacturing an oil pump, providing a first mold having at least two first inlets, filling the first mold with first injection molding material through the at least two first inlets, and forming a first rotor 11 of the oil pump in the first mold. In other words, the first rotor 11 is formed by injection molding, and the first rotor 11 includes reinforcing ribs 11b located between two adjacent inlets.

[0131] The oil pump manufacturing method provided in this application uses a first mold to process a first rotor. The first rotor formed in the first mold includes reinforcing ribs located between two adjacent feed ports, so that the reinforcing ribs can strengthen the first rotor located between the two adjacent feed ports.

[0132] The method for manufacturing an oil pump also provides a second mold, into which a second injection molding material is filled at a second inlet to form a second rotor 12 of the oil pump. The first rotor 11 meshes with the second rotor 12, and the first rotor 11 can drive the second rotor 12 to rotate. In other words, the second rotor 12 is formed by injection molding.

[0133] The reinforcing rib 11b extends from the first rotor 11 toward the side away from the second rotor 12 and protrudes from the side wall of the first rotor 11;

[0134] The first injection molding material, which is filled into the first mold through at least two first feed ports, is fused at the molten portion 11t of the first rotor 11. The molten portion 11t is located between two adjacent feed ports. The reinforcing rib 11b is located at the molten portion 11t. The reinforcing rib 11b can improve the connection strength of the first rotor 11 at the molten portion 11t, thereby improving the strength of the first rotor 11.

[0135] The oil pump of this embodiment can be applied in the automotive field; that is, the oil pump of this embodiment is a component of an automobile.

[0136] Some technical features of some implementation methods in the above embodiments can be combined or replaced.

[0137] The technical principles of this application have been described above in conjunction with specific embodiments. However, it should be noted that these descriptions are merely for explaining the principles of this application and should not be construed as limiting the scope of protection of this application in any way. Based on this explanation, other technical solutions or equivalent substitutions of this application that can be conceived by those skilled in the art without creative effort will fall within the scope of protection of this application.

Claims

1. A pump rotor assembly, characterized in that: It includes a first rotor and a second rotor. The first rotor includes a plurality of external teeth, and the second rotor includes a plurality of internal teeth. At least a portion of the external teeth meshes with at least a portion of the internal teeth. The first rotor can drive the second rotor to rotate. The first rotor is an injection molded part, and the first rotor includes reinforcing ribs that extend from the first rotor away from the external teeth and protrude from the sidewall of the first rotor.

2. The pump rotor assembly according to claim 1, characterized in that: The first rotor includes a first rotor segment A, a first rotor segment B, and a molten section. The molten section is located between the first rotor segment A and the first rotor segment B. The molten section connects the first rotor segment A and the first rotor segment B, and the first rotor segment A and the first rotor segment B are joined at the molten section to form an integral first rotor. The reinforcing rib is located in the molten section.

3. The pump rotor assembly according to claim 1 or 2, characterized in that: The first rotor includes a cylindrical portion, the external teeth are integral with the cylindrical portion, the external teeth are located on the side of the cylindrical portion away from the first rotation axis of the first rotor, the reinforcing rib is located on the inner sidewall of the cylindrical portion, and the reinforcing rib protrudes from the inner sidewall of the cylindrical portion.

4. The pump rotor assembly according to claim 3, characterized in that: At least two reinforcing ribs are provided. The reinforcing ribs are integral with the cylindrical part. The connection part between the external teeth and the cylindrical part is defined as the joint part. Along the radial direction of the first rotor, the reinforcing ribs and the joint part are respectively located on the inner arc-shaped wall and the outer arc-shaped wall of the cylindrical part.

5. The pump rotor assembly according to claim 1, 2, or 4, characterized in that: The first rotor has a first A end wall and a first B end wall, which are arranged along the first rotation axis of the first rotor; The first rotor has a first A hole and a first B hole, the first A hole is located on the first A end wall, the first B hole is located on the first B end wall, and the first rotor includes a first partition plate that isolates the first A hole and the first B hole.

6. The pump rotor assembly according to claim 5, characterized in that: The second rotor has a second A end face and a second B end face, which are arranged along the second rotation axis of the second rotor. The second rotor has a second A hole and a second B hole, the second A hole is located on the second A end face, the second B hole is located on the second B end face, and the second rotor includes a second partition plate that isolates the second A hole and the second B hole. The second rotor is an injection molded part.

7. An oil pump, characterized in that: The pump rotor assembly includes a pump rotor assembly and a rotating shaft. The rotating shaft can drive the pump rotor assembly to rotate. The pump rotor assembly includes a first rotor and a second rotor. The first rotor includes a plurality of external teeth, and the second rotor includes a plurality of internal teeth. At least a portion of the external teeth meshes with at least a portion of the internal teeth. The rotating shaft is connected to the first rotor, and the first rotor can drive the second rotor to rotate. The first rotor is an injection molded part. The first rotor includes a reinforcing rib. The rotating shaft is connected to the reinforcing rib. The reinforcing rib extends from the first rotor to the side away from the external teeth and protrudes from the side wall of the first rotor.

8. The oil pump according to claim 7, characterized in that: The first rotor includes a first rotor segment A, a first rotor segment B, and a molten section. The molten section is located between the first rotor segment A and the first rotor segment B. The molten section connects the first rotor segment A and the first rotor segment B, and the first rotor segment A and the first rotor segment B are joined at the molten section to form an integral first rotor. The reinforcing rib is located in the molten section. The shaft has a groove recessed into the outer wall of the shaft, and the reinforcing rib is at least partially located in the groove.

9. The oil pump according to claim 8, characterized in that: The reinforcing rib includes a first reinforcing rib wall, a second reinforcing rib wall, and a third reinforcing rib wall. The second reinforcing rib wall connects the first reinforcing rib wall and the third reinforcing rib wall. At least one of the first reinforcing rib wall, the second reinforcing rib wall, and the third reinforcing rib wall is interference-fitted with the wall forming the groove.

10. The oil pump according to any one of claims 7-9, characterized in that: The first rotor has a plurality of first hole groups, which are evenly distributed along the circumference of the first rotor. The first hole group includes a first A hole and a first B hole. The first A hole and the first B hole extend discontinuously along the first rotation axis of the first rotor. The first rotor includes a first partition plate located between the first A hole and the first B hole. The wall thickness of the external tooth is defined as D1, and the wall thickness of the first partition plate is defined as D2, where 0.4*D1≤D2≤0.7*D1. The second rotor is an injection molded part. The second rotor has multiple second hole groups, which are evenly distributed along the circumference of the second rotor. The second hole groups include a second A hole and a second B hole. The second A hole and the second B hole extend discontinuously along the second rotation axis of the second rotor. The second rotor includes a second partition plate, which is located between the second A hole and the second B hole. The wall thickness of the internal teeth is defined as D3, and the wall thickness of the second partition plate is defined as D4, where 0.4*D3≤D4≤0.7*D3. The rotating shaft is interference-fitted with the reinforcing rib.

11. A method for manufacturing an oil pump, characterized in that: A first mold is provided, the first mold having at least two first inlets, through which a first injection molding material is filled into the first mold, a first rotor of the oil pump is formed in the first mold, and the first rotor includes reinforcing ribs located between two adjacent inlets.

12. The method for manufacturing an oil pump according to claim 11, characterized in that: A second mold is provided, and a second injection material is filled into the second mold through a second inlet. The second rotor of the oil pump is formed in the second mold. The first rotor meshes with the second rotor, and the first rotor can drive the second rotor to rotate. The reinforcing rib extends from the first rotor toward the side away from the second rotor and protrudes from the side wall of the first rotor. The first injection molding material, filled into the first mold through at least two first feed ports, is fused at the molten portion of the first rotor, the molten portion being located between two adjacent feed ports, and the reinforcing rib being located at the molten portion.

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