Pump rotor assembly and oil pump

Abstract

A pump rotor assembly and an oil pump. The pump rotor assembly includes an inner rotor and an outer rotor, and the outer rotor is sleeved on the outer periphery of the inner rotor; the central axis of the inner rotor is offset from the central axis of the outer rotor; there is a volume chamber between the inner peripheral surface of the outer rotor and the outer peripheral surface of the inner rotor; the inner peripheral surface of the outer rotor includes a plurality of first protrusions and a plurality of first recesses, the outer peripheral surface of the inner rotor includes a plurality of second protrusions and a plurality of second recesses, and at least one of the outer rotor and the inner rotor includes a connecting portion. When the outer rotor includes a connecting portion, the corresponding connecting portion of the outer rotor is defined as the first connecting portion, and the first protrusion and the first recess adjacent to the first protrusion are connected by the first connecting portion; when the inner rotor includes a connecting portion, the corresponding connecting portion of the inner rotor is defined as the second connecting portion, and the second protrusion and the second recess adjacent to the second protrusion are connected by the second connecting portion; this is beneficial to increasing the displacement of the oil pump.

Description

Technical Field

[0001] The present invention relates to the field of vehicles, and particularly to components of a vehicle lubrication system and / or a cooling system. Background Art

[0002] An oil pump mainly provides a power source for a vehicle lubrication system and / or a cooling system; the oil pump includes a pump rotor assembly, and the structure of the pump rotor assembly is closely related to the displacement of the oil pump; usually in some systems, a large-displacement oil pump is required to meet the system requirements, so how to optimize the pump rotor assembly to increase the displacement of the oil pump is a problem that needs to be considered in the design process. Summary of the Invention

[0003] The purpose of the present invention is to provide a pump rotor assembly, which is beneficial to increasing the displacement of the oil pump.

[0004] To achieve the above purpose, an embodiment of the present invention adopts the following technical solution:

[0005] A pump rotor assembly, the pump rotor assembly includes an inner rotor and an outer rotor, the outer rotor is sleeved on the outer periphery of the inner rotor; the central axis of the inner rotor is offset from the central axis of the outer rotor; there is a volume chamber between the inner peripheral surface of the outer rotor and the outer peripheral surface of the inner rotor; the outer rotor includes a plurality of first protrusions and a plurality of first recesses, along the radial direction of the outer rotor, the first protrusions protrude towards the central axis of the outer rotor, and the first recesses are recessed in a direction away from the central axis of the outer rotor; along the circumferential direction of the outer rotor, there is a first recess between two adjacent first protrusions;

[0006] The inner rotor includes a plurality of second protrusions and a plurality of second recesses, along the radial direction of the inner rotor, the second protrusions protrude in a direction away from the central axis of the inner rotor, and the second recesses are recessed in a direction towards the central axis of the inner rotor; along the circumferential direction of the inner rotor, there is a second recess between two adjacent second protrusions;

[0007] At least one of the outer rotor and the inner rotor includes a connecting portion. When the outer rotor includes the connecting portion, the corresponding connecting portion of the outer rotor is defined as the first connecting portion. The first protrusion and the first recess adjacent to the first protrusion are connected by the first connecting portion. The ratio of the root circle diameter (D2) to the tip circle diameter (D1) of the outer rotor satisfies the following relational expression: D2 / D1 > 1.14;

[0008] When the inner rotor includes the connecting portion, the corresponding connecting portion of the inner rotor is defined as the second connecting portion. The second convex portion and the second concave portion adjacent to the second convex portion are connected by the second connecting portion. Project the inner rotor in a direction parallel to the end face of the inner rotor. In the projection of the inner rotor, the distance from the center of the inner rotor to each part of the second connecting portion is less than the distance from the center of the inner rotor to each part of the second convex portion.

[0009] An oil pump, the oil pump includes a pump shaft, a pump rotor assembly, a stator assembly, a motor rotor assembly, a first accommodation cavity and a second accommodation cavity. The pump rotor assembly is disposed in the first accommodation cavity. The stator assembly and the motor rotor assembly are disposed in the second accommodation cavity. One end of the pump rotor assembly is close to the pump shaft, and the other end of the motor rotor assembly is close to the pump shaft and connected to the pump shaft. The pump rotor assembly is the pump rotor assembly as described above.

[0010] In this technical solution, at least one of the outer rotor and the inner rotor includes a connecting portion. When the outer rotor includes the connecting portion, the corresponding connecting portion of the outer rotor is defined as the first connecting portion. The first convex portion and the first concave portion adjacent to the first convex portion are connected by the first connecting portion. The ratio of the bottom circle diameter (D2) to the top circle diameter (D1) of the outer rotor teeth satisfies the following relational expression: D2 / D1 > 1.14; by the above method, it is beneficial to increase the distance between the top circle and the bottom circle of the outer rotor teeth, and thus it is beneficial to relatively increase the distance between the first concave portion and the first convex portion. Since there is a volume cavity between the first concave portion and the outer peripheral surface of the inner rotor, it is beneficial to the volume of the volume cavity between the first concave portion and the outer peripheral surface of the inner rotor, and further beneficial to increase the displacement of the oil pump. When the inner rotor includes the connecting portion, the corresponding connecting portion of the inner rotor is defined as the second connecting portion. The second convex portion and the second concave portion adjacent to the second convex portion are connected by the second connecting portion. Project the inner rotor in a direction parallel to the end face of the inner rotor. In the projection of the inner rotor, the distance from the center of the inner rotor to each part of the second connecting portion is less than the distance from the center of the inner rotor to each part of the second convex portion. By the above method, by setting the second connecting portion, part of the contour of the outer peripheral surface of the inner rotor can be relatively close to the central axis direction of the inner rotor. Since there is a volume cavity between the second connecting portion and the inner peripheral surface of the outer rotor, it is beneficial to increase the volume of the volume cavity between the second connecting portion and the outer peripheral surface of the inner rotor, and further beneficial to increase the displacement of the oil pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a schematic cross-sectional structure diagram of the oil pump of the present application;

[0012] Figure 2 is Figure 1A front view structural schematic diagram of a partial structure of an oil pump without an assembled pump cover;

[0013] Figure 3 is Figure 1 or Figure 2 A three-dimensional structural schematic diagram of a pump rotor assembly in [[ ]];

[0014] Figure 4 is Figure 3 A front view structural schematic diagram of a pump rotor assembly in [[ ]];

[0015] Figure 5 is Figure 3 or Figure 4 A three-dimensional structural schematic diagram of an outer rotor in [[ ]];

[0016] Figure 6 is Figure 5 A front view structural schematic diagram of an outer rotor in [[ ]];

[0017] Figure 7 is Figure 6 An enlarged structural schematic diagram of part A in [[ ]];

[0018] Figure 8 is Figure 3 or Figure 4 A three-dimensional structural schematic diagram of an inner rotor in [[ ]];

[0019] Figure 9 is Figure 4 An enlarged structural schematic diagram of part B in [[ ]];

[0020] Figure 10 is Figure 3 or Figure 4 A front view structural schematic diagram of an inner rotor in [[ ]];

[0021] Figure 11 is Figure 10 An enlarged structural schematic diagram of part C in [[ ]]. Detailed implementation manners

[0022] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

[0023] The oil pump in this embodiment can mainly provide the driving force for the working medium of the vehicle lubrication system and / or cooling system, specifically for the working medium of the lubrication system and / or cooling system in the vehicle transmission system; the oil pump in this embodiment can be a mechanical oil pump or an electric oil pump. The following takes the electric oil pump as an example for detailed introduction.

[0024] See Figure 1, the oil pump 100 includes a pump housing, a pump rotor assembly 1, a stator assembly 4, a motor rotor assembly 2, a pump shaft 3, and an electronic control board assembly 5; the pump rotor assembly 1, the motor rotor assembly 2, and the electronic control board assembly 5 are arranged along the axial direction of the oil pump 100, the motor rotor assembly 2 is located between the pump rotor assembly 1 and the electronic control board assembly 5, the stator assembly 4 is located on the outer periphery of the motor rotor assembly 2, one end of the pump rotor assembly 1 is close to the pump shaft 3, the other end of the motor rotor assembly 2 is close to the pump shaft 3, and the motor rotor assembly 2 drives the pump rotor assembly 1 to rotate through the pump shaft 3; the oil pump 100 further includes a first accommodation cavity 80 and a second accommodation cavity 90, the pump rotor assembly 1 is located in the first accommodation cavity 80, and the stator assembly 4 and the motor rotor assembly 2 are located in the second accommodation cavity 90; see Figure 1 , the stator assembly 4 includes a stator core 41 and a coil 42. When the oil pump 100 works, the electronic control board assembly 5 controls the current passing through the coil 42 of the stator assembly 4 to change according to a predetermined law, so as to control the stator assembly 4 to generate a changing excitation magnetic field. The motor rotor assembly 2 rotates under the action of the excitation magnetic field, and the motor rotor assembly 2 can directly or indirectly drive the pump rotor assembly 1 to rotate. When the pump rotor assembly 1 rotates, the volume of the volume cavity between the pump rotor assemblies 1 changes, so that the working medium is pressed out to the outflow channel 62 to generate a flowing power.

[0025] See Figure 1 , the pump housing includes a pump cover 6, a first housing 7, and a second housing 8. The pump cover 6 and the first housing 7 are connected by screws or bolts. Of course, the pump cover 6 and the first housing 7 can also be connected by other means, such as plugging, clamping, etc.; the first housing 7 and the second housing 8 are connected by screws or bolts. Specifically, in this embodiment, the oil pump 100 further includes an isolation member 9, and the isolation member 9 can prevent the working medium in the second accommodation cavity 90 from flowing into the cavity where the electronic control board assembly 5 is located, which is beneficial to preventing the working medium in the second accommodation cavity 90 from affecting the performance of the electronic control board assembly 5. See Figure 1, a screw or bolt sequentially passes through the second housing 8, the spacer 9, and the first housing 7, so that the first housing 7 and the second housing 8 are indirectly fixedly connected. Of course, the first housing 7 and the second housing 8 can also be directly fixedly connected by screws or bolts without passing through the spacer 9. At this time, the structure of the spacer 9 will change accordingly. At this time, the spacer 9 can be positioned by being tightly fitted with the inner peripheral side wall of the first housing 7; the connection method of the first housing 7 and the second housing 8 by screws or bolts is beneficial to making the disassembly and assembly of the oil pump more convenient. In this embodiment, since the electronic control board assembly 5 is disposed in the cavity between the second housing 8 and the spacer 9, this is also beneficial to the maintenance of the electronic control board assembly 5 in the oil pump. Of course, the first housing 7 and the second housing 8 can also be connected by other connection methods such as plugging, clamping, etc.; in addition, in this embodiment, the first accommodation cavity 80 and the second accommodation cavity 90 are formed by the pump housing. Specifically, the first accommodation cavity 80 is formed between the pump cover 6 and the first housing 7, and the second accommodation cavity 90 is formed between the first housing 7 and the second housing 8. Of course, it is also possible not to include the pump housing, but to directly assemble other components except the pump housing with the vehicle transmission. At this time, a partition can be provided. On the one hand, it supports the pump rotor assembly 1, and on the other hand, the partition can also be used as the boundary between the first accommodation cavity 80 and the second accommodation cavity 90.

[0026] See again Figure 1 and Figure 2 , the oil pump 100 further includes an inlet flow channel 61 and an outlet flow channel 62. The inlet flow channel 61 is used for the inflow of the working medium, and the outlet flow channel 62 is used for the outflow of the working medium. Specifically, the working medium can enter the volume cavity 801 through the inlet flow channel 61, and the working medium can leave the volume cavity 801 through the outlet flow channel 62; in this embodiment, both the inlet flow channel 61 and the outlet flow channel 62 are formed on the pump cover 6. Of course, when the pump cover 6 is not included, other components except the pump cover 6 can be directly assembled with the vehicle transmission or other components on the vehicle. At this time, the inlet flow channel 61 and the outlet flow channel 62 can be correspondingly provided on the transmission or other components on the vehicle; see Figure 2, during one rotation of the pump rotor assembly 1, the volume of the volume chamber formed between the outer peripheral surface of the inner rotor 11 and the inner peripheral surface of the outer rotor 12 will change. Specifically, during the process of the pump rotor assembly 1 rotating from the starting point to a certain angle, the volume of some of the volume chambers formed between the outer peripheral surface of the inner rotor 11 and the inner peripheral surface of the outer rotor 12 will gradually increase, thus forming a local vacuum. At this time, the working medium is sucked from the inflow channel 61 into the volume chamber 801. During the continuous rotation of the inner rotor 11 and the outer rotor 12, along the rotation direction of the pump rotor assembly 1, the volume of some of the volume chambers formed between the outer peripheral surface of the inner rotor 11 and the inner peripheral surface of the outer rotor 12 will gradually decrease, and the working medium is squeezed, so that the working medium entering the volume chamber 801 is pressed out to the outflow channel 62, thus generating the power of flow.

[0027] See Figures 2 to 4 , in this embodiment, the pump rotor assembly 1 includes an inner rotor 11 and an outer rotor 12. The inner rotor 11 is connected to Figure 1 the pump shaft 3 in. In this embodiment, the outer rotor 12 is located on the outer periphery of the inner rotor 11. The inner rotor 11 and the outer rotor 12 are internally meshed. There are multiple volume chambers 801 between the outer peripheral surface of the inner rotor 11 and the inner peripheral surface of the outer rotor 12. Of course, the outer rotor 12 and the inner rotor 11 can also be externally meshed. At this time, the inner rotor 11 and the outer rotor 12 are arranged side by side. In this embodiment, the central axis of the inner rotor 11 and the central axis of the outer rotor 12 are offset, that is to say, there is a certain eccentricity e between the central axis of the inner rotor 11 and the central axis of the outer rotor 12; See Figure 5 and Figure 6 , the inner peripheral surface of the outer rotor 12 includes multiple first protrusions 121 and multiple first recesses 122. Along the radial direction of the outer rotor 12, the first protrusions 121 protrude towards the central axis C1 of the outer rotor 12, and the first recesses 122 are recessed away from the central axis C1 of the outer rotor 12. Along the circumferential direction of the outer rotor 12, there is one first recess 122 between two adjacent first protrusions 121, or there is one first protrusion 121 between two adjacent first recesses 122. That is to say, the first protrusions 121 and the first recesses 122 are arranged at intervals; See Figure 8 , the outer peripheral surface of the inner rotor 11 includes multiple second protrusions 111 and multiple second recesses 112. Along the radial direction of the inner rotor 11, the second protrusions 111 protrude away from the central axis C2 of the inner rotor 11, and the second recesses 112 are recessed towards the central axis of the inner rotor 11. Along the circumferential direction of the inner rotor 11, there is one second recess 112 between two adjacent second protrusions 111, or there is one second protrusion 111 between two adjacent second recesses 112. That is to say, the second protrusions 111 and the second recesses 112 are arranged at intervals; See Figure 4, the second protrusion 111 is corresponding to the first recess 122, and the second recess 112 is corresponding to the first protrusion 121; Figure 1 、 Figure 2 as well as Figure 4 When the inner rotor 11 rotates, the second protrusion 111 of the inner rotor 11 engages with the first recess 122 of the outer rotor 12 and / or the second recess 112 of the inner rotor 11 engages with the first protrusion 121 of the outer rotor 12, so that the inner rotor 11 can drive the outer rotor 12 to rotate.

[0028] See also Figures 5 to 7 In this embodiment, the first protrusion 121 and the first recess 122 adjacent to the first protrusion 121 are connected by a first connecting portion 123, see Figure 6 The ratio of the outer rotor tooth bottom circle diameter D2 to the outer rotor tooth tip circle diameter D1 satisfies the following relationship: D2 / D1>1.14; this is conducive to increasing the distance between the outer rotor tooth tip circle and the outer rotor tooth bottom circle, thereby facilitating an increase in the distance between the first recess and the first protrusion. Since there is a volume cavity between the first recess and the outer peripheral surface of the inner rotor, this is conducive to increasing the volume of the volume cavity between the first recess and the outer peripheral surface of the inner rotor, thereby facilitating an increase in the displacement of the oil pump; in addition, the ratio of the outer rotor tooth bottom circle diameter D2 to the outer rotor tooth tip circle diameter D1 also satisfies the following relationship: D2 / D1<1.32, where the value "1.32" can be a fixed value or a rounded value, which is conducive to preventing the outer rotor tooth tip circle from crossing the outer peripheral boundary of the outer rotor; see Figure 6 and Figure 7 For ease of description, an imaginary reference body is introduced here: the first virtual recess 124. The first virtual recess 124 is directly connected to one end of the two adjacent first protrusions 121. The first recess 122 is closer to the outer circumferential surface of the outer rotor than the first virtual recess 124. In other words, it is equivalent to moving the first recess 122 relatively outward. In this embodiment, the tooth bottom circle diameter D3 of the first virtual recess 124 satisfies the following relationship: D3 = 1.14D1. In this way, the first recess 122 is closer to the outer circumferential surface of the outer rotor 12. Since there is a volume cavity between the first recess 122 and the outer circumferential surface of the inner rotor, the volume of the volume cavity between the first recess 122 and the outer circumferential surface of the inner rotor is increased, thereby facilitating an increase in the displacement of the oil pump. In addition, see Figures 5 to 7, here, for the convenience of showing the first connecting portion 123 and the first virtual concave portion 124, the first connecting portion 123 is marked with a thick solid line, and the first virtual concave portion 124 is marked with a dotted line. In this embodiment, the main body of the first connecting portion 123 is planar. There are two cases here. The first case is that the entire surface of the first connecting portion 123 is planar. In this way, edges will be formed at the joints of the first connecting portion 123 with the first convex portion 121 and the first concave portion 122. Of course, the edges formed at the joints of the first connecting portion 123 with the first convex portion 121 and the first concave portion 122 can also be polished into a smooth surface by a polishing process. The second case is that the joint of the first connecting portion 123 and the first convex portion 121 is smoothly connected through an arc or a curved surface, and / or the joint of the first connecting portion 123 and the first concave portion 122 is smoothly connected through an arc or a curved surface. In this embodiment, the main body of the first connecting portion 123 is planar. Of course, the first connecting portion 123 can also be concave. When the first connecting portion 123 is concave, the first connecting portion 123 is recessed toward the direction close to the outer peripheral surface of the outer rotor 12. Of course, small protrusions can also be provided locally on the first connecting portion 123, or the first connecting portion 123 is convex. At this time, the convex surface of the first connecting portion 123 should be relatively gentle. The cross-section of the convex first connecting portion can be arc-shaped. This arc shape can be formed by point description or composed of an arc. Of course, the first connecting portion 123 can also be a combination of two or more of a curved surface shape, a planar shape, and a convex shape, etc. See Figure 5 and Figure 6 , the minimum distance between the first concave portion 122 and the outer peripheral surface 120 of the outer rotor 12 is greater than or equal to 1 mm. Here, the "outer peripheral surface 120 of the outer rotor 12" does not include the outer peripheral surface formed by the chamfer of the outer rotor 12. This is beneficial to ensuring the structural strength of the first concave portion 122. In addition, the "1 mm" here is a theoretical distance. Since there will be errors in the processing and manufacturing process, all errors in the processing and manufacturing process are within the protection scope of this application.

[0029] See Figure 6 and Figure 7 , at least one of at least part of the outer surface of the first convex portion 121 and at least part of the outer surface of the first concave portion 122 is arc-shaped. Here, it includes the following three cases:

[0030] The first case: In the outer surface of the first convex portion 121, the outer surface corresponding to the portion where the first convex portion 121 is directly connected to the first connecting portion 123 is arc-shaped, and the first connecting portion 123 is tangent to the arc-shaped outer surface of the first convex portion 121. In this way, when the working medium flows from the first connecting portion 123 to the first convex portion 121 or when the working medium flows from the first convex portion 121 to the first connecting portion 123, it is beneficial to improve the smoothness of the working medium at the connection between the first connecting portion 123 and the first convex portion 123; in the first case, the outer surface corresponding to the portion of the first convex portion 121 that is not directly connected to the first connecting portion 123 may be arc-shaped. Here, the outer surface corresponding to the portion of the first convex portion 121 that is not directly connected to the first connecting portion 123 may be an arc surface composed of a single arc, or an arc surface composed of two or more arcs. Among them, the arc surface composed of a single arc and the arc surface corresponding to the portion of the first convex portion 121 that is directly connected to the first connecting portion 123 may be the same arc, or different arcs with different diameters; of course, the portion of the first convex portion 121 that is not directly connected to the first connecting portion 123 may also be a curved surface composed of a fitting curve fitted by multiple points;

[0031] The second case: In the outer surface of the first concave portion 122, the outer surface corresponding to the portion where the first concave portion 122 is directly connected to the first connecting portion 123 is arc-shaped, and the first connecting portion 123 is tangent to the arc-shaped outer surface of the first concave portion 122. In this way, when the working medium flows from the first connecting portion 123 to the first concave portion 122 or when the working medium flows from the first concave portion 122 to the first connecting portion 123, it is beneficial to improve the smoothness of the working medium at the connection between the first connecting portion 123 and the first concave portion 122; in the second case, the outer surface corresponding to the portion of the first concave portion 122 that is not directly connected to the first connecting portion 123 may be arc-shaped. Here, the outer surface corresponding to the portion of the first concave portion 122 that is not directly connected to the first connecting portion 123 may be an arc surface composed of a single arc, or an arc surface composed of two or more arcs. Among them, the arc surface composed of a single arc and the arc surface corresponding to the portion of the first concave portion 122 that is directly connected to the first connecting portion 123 may be the same arc, or different arcs with different diameters; of course, the portion of the first concave portion 122 that is not directly connected to the first connecting portion 123 may also be a curved surface composed of a fitting curve fitted by multiple points;

[0032] The third case: Refer to Figure 6 and Figure 7, in the outer surface of the first convex portion 121, the outer surface corresponding to the portion where the first convex portion 121 is directly connected to the first connecting portion 123 is arc-shaped; in the outer surface of the first concave portion 122, the outer surface corresponding to the portion where the first concave portion 122 is directly connected to the first connecting portion 123 is arc-shaped; one end of the first connecting portion 123 is tangent to the arc-shaped outer surface of the first convex portion 121, and the other end of the first connecting portion 123 is tangent to the arc-shaped outer surface of the first concave portion 122. Thus, when the working medium flows from the first connecting portion 123 to the first concave portion 122 or when the working medium flows from the first concave portion 122 to the first connecting portion 123, it is beneficial to improve the smoothness of the working medium at the connection between the first connecting portion 123 and the first concave portion 122. When the working medium flows from the first connecting portion 123 to the first concave portion 122 or when the working medium flows from the first concave portion 122 to the first connecting portion 123, it is beneficial to improve the smoothness of the working medium at the connection between the first connecting portion 123 and the first concave portion 122; in the third case, the outer surface corresponding to the portion of the first convex portion 121 that is not directly connected to the first connecting portion 123 may be arc-shaped. Here, the outer surface corresponding to the portion of the first convex portion 121 that is not directly connected to the first connecting portion 123 may be an arc surface composed of a single arc, or an arc surface composed of two or more arcs. Among them, the arc surface composed of a single arc and the arc surface corresponding to the portion of the first convex portion 121 that is directly connected to the first connecting portion 123 may be the same arc, or different arcs with different diameters. Of course, the portion of the first convex portion 121 that is not directly connected to the first connecting portion 123 may also be a curved surface composed of a fitting curve formed by fitting multiple points. Specifically, refer to Figure 6 and Figure 7 , in this embodiment, the outer surface of the first convex portion 121 is all arc-shaped, and the entire outer surface of the first convex portion 121 is an arc surface composed of a single arc; in the third case, the outer surface corresponding to the portion of the first concave portion 122 that is not directly connected to the first connecting portion 123 may be arc-shaped. Here, the outer surface corresponding to the portion of the first concave portion 122 that is not directly connected to the first connecting portion 123 may be an arc surface composed of a single arc, or an arc surface composed of two or more arcs. Among them, the arc surface composed of a single arc and the arc surface corresponding to the portion of the first concave portion 122 that is directly connected to the first connecting portion 123 may be the same arc, or different arcs with different diameters. Of course, the portion of the first concave portion 122 that is not directly connected to the first connecting portion 122 may also be a curved surface composed of a fitting curve formed by fitting multiple points. Specifically, refer to Figure 6 and Figure 7 , in this embodiment, the outer surface of the first concave portion 122 is all arc-shaped, and the entire outer surface of the first concave portion 122 is an arc surface composed of a single arc; the following takes the above third case as an example for detailed introduction.

[0033] See Figures 5 to 7 , in this embodiment, the area of the first convex portion 121 is larger than the area of the outer surface of the first concave portion 122; for one of the first convex portions 121 and the two first connecting portions 123 respectively connected to both ends of the first convex portion 121, the two adjacent first connecting portions 123 are symmetrically distributed with respect to the central plane of the first convex portion 121.

[0034] See Figure 4 and Figure 9 , the flow area of at least a part of the volume chambers in the minimum volume chamber 8010 between the inner peripheral surface of the outer rotor 12 and the outer peripheral surface of the inner rotor 11 gradually decreases along the rotation direction of the pump rotor assembly 1. In this embodiment, the rotation direction of the pump rotor assembly 1 is counterclockwise. Here, "counterclockwise" is the view from the top when the electric pump without a cross-section is placed in the Figure 1 state; for the convenience of describing the minimum volume chamber 8010, see Figure 4 , the area where the volume chamber is located between the inner peripheral surface of the outer rotor 12 and the outer peripheral surface of the inner rotor 11 is divided into a first area 101 and a second area 102. For better distinction between the first area 101 and the second area 102 on the drawing, see Figure 4 , the first area 101 and the second area 102 are distinguished by two different hatching patterns respectively; in the first area 101, the volume in the volume chamber formed by the outer peripheral surface of the inner rotor 11 and the inner peripheral surface of the outer rotor 12 gradually increases from the head of the first area 101 to the tail of the first area 101 along the rotation direction of the pump rotor assembly 1, so that a local vacuum can be formed in the first area 101. Combining Figure 1 , at this time, the working medium is sucked from the inflow channel 61 into the first area 101; in the second area 102, the volume of the volume chamber formed by the outer peripheral surface of the inner rotor 11 and the inner peripheral surface of the outer rotor 12 gradually decreases from the head of the second area 102 to the tail of the second area 102 along the rotation direction of the pump rotor assembly 1, so that the working medium is squeezed in the second area 102, and then the pressure of the working medium located in the second area 102 gradually increases. Among them, the minimum volume chamber 8010 is located at the tail of the second area 102, and the minimum volume chamber 8010 can communicate with the volume chamber located in the first area 101.

[0035] See Figures 4 to 9, in this embodiment, the minimum volume chamber 8010 is located between one of the first convex portions 121 of the outer rotor 11 and one of the second concave portions 112 of the inner rotor; define the first convex portion 121 corresponding to one side wall of the minimum volume chamber 8010 as the first reference convex portion 1211, and define the second concave portion corresponding to the other side wall of the minimum volume chamber as the second reference concave portion 1121. Project the pump rotor assembly 1 in a direction parallel to the end face of the pump rotor assembly 1, and define the first reference line L1 and the second reference line L2. The first reference line L1 is the connection line between the center O2 of the inner rotor and the tooth bottom tangent point of the second reference concave portion 1121, and the second reference line L1 is the connection line between the center O2 of the inner rotor and the center of the first reference convex portion 1211. The first reference line L1 and the second reference line L2 are arranged at an angle; specifically, the offset direction of the second reference line L2 relative to the first reference line L1 is the same as the rotation direction of the pump rotor assembly 1, so that at least part of the flow area of the volume chambers in the minimum volume chamber 8010 can gradually decrease along the rotation direction of the pump rotor assembly 1. Compared with the case where the volume of the minimum volume chamber remains unchanged, when the pump rotor assembly 1 is working, on the one hand, it is beneficial to relatively reduce the flow rate of the working medium at the tail of the second region 102 flowing to the first region 101, thereby being beneficial to improving the pump efficiency. On the other hand, it is beneficial to improve the smoothness of the working medium flowing in the minimum volume chamber 8010, and then beneficial to reducing the pressure fluctuation of the working medium, thereby being beneficial to reducing noise; in addition, in this embodiment, the angle α between the first reference line L1 and the second reference line L2 is greater than 0° and less than or equal to 2.5°, which is beneficial to preventing structural interference between the first reference convex portion 1211 and the second reference concave portion 1121.

[0036] See Figure 10 and Figure 11 , the inner rotor 11 includes a second connecting portion 113. The second convex portion 111 and the second concave portion 112 adjacent to the second convex portion 111 are connected by the second connecting portion 113. Project the inner rotor 11 in a direction parallel to the end face of the inner rotor 11. In the projection of the inner rotor 11, the distance L3 from the center O2 of the inner rotor 11 to each part of the second connecting portion 113 is less than the distance L4 from the center O2 of the inner rotor 11 to each part of the second convex portion; by the above method, by setting the second connecting portion, part of the contour of the outer peripheral surface of the inner rotor can be relatively close to the central axis direction of the inner rotor. Since there is a volume chamber between the second connecting portion and the inner peripheral surface of the outer rotor, it is beneficial to increase the volume of the volume chamber between the second connecting portion and the outer peripheral surface of the inner rotor, and then beneficial to improving the displacement of the oil pump. See Figure 10 and Figure 11 , for one of the second convex portions 111 and the two second connecting portions 113 respectively connected to both ends of the second convex portion 111, the two adjacent second connecting portions 113 are symmetrically distributed with respect to the central plane of the second convex portion 111.

[0037] See Figure 10 and Figure 11 In this embodiment, the main body of the second connecting portion 113 is planar, and there are two cases here: The first case is that the entire surface of the second connecting portion 113 is planar, and in this way, edges will be formed at the joints of the second connecting portion 113 with the second convex portion 111 and the second concave portion 112; The second case is that the joint of the second connecting portion 113 and the second convex portion 111 is smoothly connected through an arc or a curved surface, and / or the joint of the second connecting portion 113 and the second concave portion 112 is smoothly connected through an arc or a curved surface; See Figure 10 and Figure 11 For the convenience of description, a hypothetical reference body is introduced here: a virtual extension portion 114. The virtual extension portion 114 is an extension segment of the second convex portion 111, and the second connecting portion 113 is closer to the central axis of the inner rotor 11 than the virtual extension portion 114. That is to say, the second connecting portion 113 is arranged closer to the inside relative to the virtual extension portion 114. By arranging the second connecting portion 113, a partial contour of the outer peripheral surface of the inner rotor 11 can be made to approach the central axis direction of the inner rotor 11. Since there is a volume chamber between the second connecting portion 113 and the inner peripheral surface of the outer rotor, it is thus beneficial to increase the volume of the volume chamber between the second connecting portion 113 and the outer peripheral surface of the inner rotor, and further beneficial to increasing the displacement of the oil pump; See Figure 10 and Figure 11 Here, in order to facilitate showing the second connecting portion 113 and the extension portion 114 of the second convex portion 111, the second connecting portion 113 is marked with a thick solid line, and the extension portion 114 of the second convex portion 111 is marked with a dotted line; In this embodiment, the second connecting portion 113 is planar. Of course, the second connecting portion 113 can also be concave. When the second connecting portion 113 is concave, the second connecting portion 113 is recessed in the direction close to the central axis of the inner rotor 11; Of course, the second connecting portion 113 can also be a combined shape of planar and concave, etc.; The shapes of the second convex portion 111 and the second concave portion 112 here can respectively refer to the descriptions of the first convex portion 111 and the second concave portion 112 in the above text, and will not be elaborated here one by one.

[0038] In addition, see Figures 3 to 11 In this embodiment, the outer rotor 12 has a first connecting portion 123, and the inner rotor 11 has a second connecting portion 113. That is to say, connecting portions are provided on both the outer rotor 12 and the inner rotor 11. Of course, only one of the outer rotor 12 and the inner rotor 11 may include a connecting portion, and this can also increase the displacement of the oil pump.

[0039] It should be noted that the above embodiments are only used to illustrate the present invention and do not limit the technical solutions described in the present invention. Although this specification has described the present invention in detail with reference to the above embodiments, those of ordinary skill in the art should understand that those skilled in the art can still modify or equivalently replace the present invention, and all technical solutions and their improvements that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A pump rotor assembly, characterized in that: The pump rotor assembly includes an inner rotor and an outer rotor, wherein the outer rotor is sleeved on the outer circumference of the inner rotor; the central axis of the inner rotor is offset from the central axis of the outer rotor; a volume cavity is defined between the inner circumferential surface of the outer rotor and the outer circumferential surface of the inner rotor; the outer rotor includes a plurality of first protrusions and a plurality of first recesses, wherein along the radial direction of the outer rotor, the first protrusions are provided to protrude toward the central axis of the outer rotor, and the first recesses are provided to be recessed in a direction away from the central axis of the outer rotor; and along the circumference of the outer rotor, two adjacent first protrusions have the first recesses; The inner rotor includes a plurality of second protrusions and a plurality of second recesses. Along the radial direction of the inner rotor, the second protrusions are arranged to protrude away from the central axis of the inner rotor, and the second recesses are arranged to be recessed toward the central axis of the inner rotor. Along the circumferential direction of the inner rotor, two adjacent second protrusions have a second recess. At least one of the outer rotor and the inner rotor includes a connecting portion. When the outer rotor includes the connecting portion, the connecting portion corresponding to the outer rotor is defined as a first connecting portion. The first protrusion and the first recess adjacent to the first protrusion are connected by the first connecting portion. The ratio of the tooth base circle diameter D2 of the outer rotor to the tooth tip circle diameter D1 of the outer rotor satisfies the following relationship: 1.14 <D2 / D1<1.32; When the inner rotor includes the connecting portion, the connecting portion corresponding to the inner rotor is defined as a second connecting portion, and the second protrusion and the second recess adjacent to the second protrusion are connected via the second connecting portion. When the inner rotor is projected in a direction parallel to the end face of the inner rotor, in the projection of the inner rotor, the distance from the center of the inner rotor to each point of the second connecting portion is less than the distance from the center of the inner rotor to each point of the second protrusion. The main body of the first connecting portion is planar or concave. When the main body of the first connecting portion is concave, the first connecting portion is recessed in a direction close to the outer circumferential surface of the outer rotor. The main body of the second connecting portion is planar or concave.

2. The pump rotor assembly according to claim 1, characterized in that: When the main body of the first connecting portion is planar, the outer surface of the first protrusion corresponding to the portion where the first protrusion is directly connected to the first connecting portion is arc-shaped, and the first connecting portion is tangent to the arc-shaped outer surface of the first protrusion.

3. The pump rotor assembly according to claim 1, characterized in that: When the main body of the connecting portion is planar, the outer surface of the first recess corresponding to the portion where the first recess is directly connected to the first connecting portion is arcuate, and the first connecting portion is tangent to the arcuate outer surface of the first recess.

4. The pump rotor assembly according to claim 1, characterized in that: When the main body of the first connecting part is planar, in the outer surface of the first protrusion, the outer surface corresponding to the part directly connected to the first connecting part is arc-shaped; in the outer surface of the first recessed part, the outer surface corresponding to the part directly connected to the first connecting part is arc-shaped; one end of the first connecting part is tangent to the outer surface of the first protrusion that is in the shape of an arc, and the other end of the first connecting part is tangent to the outer surface of the first recessed part that is in the shape of an arc.

5. The pump rotor assembly according to claim 4, characterized in that: The outer surface of the first protrusion is an arc surface formed by a segment of circular arc, and the outer surface of the first recess is an arc surface formed by a segment of circular arc; for one of the first protrusions and the two first connecting portions respectively connected to the two ends of the first protrusion, the two adjacent first connecting portions are symmetrically distributed about the center plane of the first protrusion.

6. The pump rotor assembly according to any one of claims 1 to 5, characterized in that: The flow area of at least a portion of the minimum volume cavity between the inner circumferential surface of the outer rotor and the outer circumferential surface of the inner rotor gradually decreases along the rotation direction of the pump rotor assembly.

7. The pump rotor assembly according to claim 6, characterized in that: The minimum volume cavity is located between one of the first protrusions of the outer rotor and one of the second recesses of the inner rotor; the first protrusion corresponding to one side wall of the minimum volume cavity is defined as a first reference protrusion, and the second recess corresponding to the other side wall of the minimum volume cavity is defined as a second reference recess. The pump rotor assembly is projected in a direction parallel to the end face of the pump rotor assembly to define a first reference line and a second reference line. The first reference line is a line connecting the center of the inner rotor and the tooth bottom tangent point of the second reference recess, and the second reference line is a line connecting the center of the inner rotor and the center of the first reference protrusion. The first reference line and the second reference line are set at an angle.

8. The pump rotor assembly according to claim 7, characterized in that: The offset direction of the second reference line relative to the first reference line is the same as the rotation direction of the pump rotor assembly, and the angle between the first reference line and the second reference line is greater than 0° and less than or equal to 2.5°.

9. An oil pump, comprising a pump shaft, a pump rotor assembly, a stator assembly, a motor rotor assembly, a first accommodating chamber and a second accommodating chamber, wherein the pump rotor assembly is arranged in the first accommodating chamber, the stator assembly and the motor rotor assembly are arranged in the second accommodating chamber, the pump rotor assembly is close to one end of the pump shaft, and the motor rotor assembly is close to the other end of the pump shaft and connected to the pump shaft, and the pump rotor assembly is the pump rotor assembly according to any one of claims 1 to 8.

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