Electric water pump

Abstract

The utility model discloses an electric water pump which comprises a shell, a pump shaft, a brushless motor, an impeller and an electric control board, and the shell is provided with a water inlet, a water outlet, an impeller cavity, a rotor cavity and an electric control cavity. A cavity wall between the electric control cavity and the rotor cavity forms a heat conduction wall, and the minimum thickness of the heat conduction wall is 0.5 mm; the second end of the pump shaft is positioned in the rotor cavity and is suspended on the heat conduction wall; the electric control board is arranged in the electric control cavity and electrically connected with the stator to control the stator, and the electric control board is attached to the heat conduction wall. The heat dissipation efficiency of the electric control board is high.

Description

TECHNICAL FIELD

[0001] The utility model relates to water pump field, concretely relates to a kind of electric water pump. BACKGROUND

[0002] In prior art, centrifugal electric water pump using permanent magnet brushless motor has been widely used in cooling water circulation system of automobile industry.This electric water pump generally includes shell, pump shaft, brushless motor, electric control board and impeller.Shell is generally formed by upper shell, middle shell and lower shell fixed connection;Upper shell is provided with impeller cavity, water inlet and water outlet, water inlet is axially communicated with impeller cavity, and water outlet is tangentially communicated with impeller cavity;Middle shell is provided with rotor cavity, and upper shell and middle shell are water-tightly fixed to make impeller cavity and rotor cavity axially communicated.Middle shell and lower shell are fixed and enclosed to form electric control cavity.Impeller is placed in impeller cavity, rotor of brushless motor is placed in rotor cavity, stator of brushless motor (including stator part and winding part) is arranged around rotor cavity and fixed with shell, and electric control board is used to control stator and placed in electric control cavity.Pump shaft, rotor and impeller are integrally fixed, and pump shaft is supported by bearing fixed with support plate between rotor and impeller, and support plate is fixed with stator.Lower end of pump shaft is supported by bearing fixed with lower shell.Pump shaft, rotor and impeller fixed with each other are driven by brushless motor to make water flow from water inlet through impeller and pump out from water outlet.However, in the above prior art, the heat dissipation efficiency of electric control board is poor. SUMMARY

[0003] The utility model aims at overcoming the above-mentioned defects or problems existing in the background art, and provides an electric water pump with high heat dissipation efficiency of electric control board.

[0004] To achieve the above-mentioned purpose, the utility model and its preferred embodiments adopt the following technical solutions, but the embodiments are not limited to the following solutions:

[0005] The first technical solution and its related embodiments provide an electric water pump, which includes shell provided with water inlet, water outlet, impeller cavity, rotor cavity and electric control cavity;Water inlet and water outlet are communicated with impeller cavity, and rotor cavity is axially communicated with impeller cavity;Electric control cavity is adjacent to rotor cavity and axially away from impeller cavity;Cavity wall between electric control cavity and rotor cavity forms heat conduction wall, and the minimum thickness of heat conduction wall is 0.5mm;Pump shaft, whose first end is located in impeller cavity and second end is located in rotor cavity and suspended in heat conduction wall;Brushless motor, which includes rotor and stator, rotor is located in rotor cavity and rotationally connected with pump shaft;Stator is fixed with shell and arranged outside rotor cavity;Impeller is located in impeller cavity and fixed with rotor;And electric control board is arranged in electric control cavity and electrically connected with stator to control stator, and electric control board is attached to heat conduction wall.

[0006] Based on the first technical solution, a second technical solution is also provided, and in the second technical solution and related embodiments, the maximum thickness of the heat-conducting wall is 1.5 mm.

[0007] Based on the first technical solution, a third technical solution is also provided, and in the third technical solution and related embodiments, a connecting piece is further included; the first end of the pump shaft is fixedly connected to the cavity wall of the impeller cavity through the connecting piece.

[0008] Based on the third technical solution, a fourth technical solution is also provided, and in the fourth technical solution and related embodiments, the rotor includes a rotating sleeve and a rotor part that are fixedly connected to each other, the rotating sleeve is sleeved on the pump shaft and gap-fitted with the pump shaft, and the rotor part is sleeved outside the rotating sleeve; the connecting piece is made of metal material and is provided with a limiting wall adapted to directly abut against the rotating sleeve.

[0009] Based on the fourth technical solution, a fifth technical solution is also provided, and in the fifth technical solution and related embodiments, the connecting piece is provided with a connecting body and at least two connecting ribs, the connecting body is sleeved on the first end of the pump shaft and has a bullet head shape that faces the water inlet; one end of each connecting rib is fixedly connected to the connecting body, and the other end is fixedly connected to the cavity wall of the impeller cavity, and each connecting rib is arranged in the circumferential direction; the lower end surface of the connecting body forms the limiting wall.

[0010] Based on the fourth technical solution, a sixth technical solution is also provided, and in the sixth technical solution and related embodiments, a lower limiting piece is further included; the rotor and the impeller are allowed to axially slide relative to the pump shaft, the limiting wall limits the upward movement of the rotor and the impeller; the lower limiting piece is fixedly connected to the pump shaft and is used to limit the downward movement of the rotor and the impeller.

[0011] Based on any one of the fourth to sixth technical solutions, a seventh technical solution is also provided, and in the seventh technical solution and related embodiments, the shell includes an upper shell, a middle shell, and a lower shell, the upper shell and the middle shell are fixedly and watertightly connected, the lower shell is fixedly connected to the middle shell, the impeller cavity, the water inlet, and the water outlet are formed in the upper shell, the rotor cavity is formed in the middle shell, and the middle shell and the lower shell enclose the electric control cavity.

[0012] Based on the seventh technical solution, an eighth technical solution is also provided, and in the eighth technical solution and related embodiments, the upper shell is made of plastic material, and the connecting piece is integrally formed with the upper shell by insert injection molding.

[0013] Based on the seventh technical solution, a ninth technical solution is also provided, and in the ninth technical solution and related embodiments, the upper shell is made of metal material, and the connecting piece is welded to the upper shell.

[0014] Based on the seventh technical solution, the tenth technical solution is further provided, and in the tenth technical solution and the related embodiments, the pump shaft is provided with a water passage along the extension direction of the pump shaft, a high-pressure area is formed between the impeller and the cavity wall of the impeller cavity, the high-pressure area is communicated to a low-pressure area close to the water inlet through the rotor cavity and the water passage, a heat dissipation wall is formed by the side cavity wall of the rotor cavity, a water passage gap is formed between the heat dissipation wall and the rotor, and the water passage gap is used to communicate the high-pressure area and the water passage.

[0015] As can be seen from the above description of the utility model and its preferred embodiments, compared with the prior art, the technical solution and the preferred embodiments of the utility model have the following beneficial effects due to the following technical means:

[0016] In the first technical solution, since the second end of the pump shaft is located in the rotor cavity and is suspended on the heat conduction wall, the vibration of the rotor and the impeller is not easily transmitted to the heat conduction wall through the pump shaft, and the heat conduction wall is not easily cracked. In the prior art, in order to avoid cracking of the heat conduction wall, the heat conduction wall is often thickened, and a limiting structure is often protruded on the heat conduction wall to cooperate with the second end of the pump shaft. After the electric control board is attached to the heat conduction plate, since the heat conduction wall is thick, the heat of the electric control board cannot be well transmitted to the side of the heat conduction wall located in the rotor cavity. In addition, the limiting structure protruded on the heat conduction wall occupies the space in the rotor cavity and is often located at the center of the heat conduction wall. The cooling liquid in the rotor cavity can only flow around the limiting structure, and the cooling liquid in the rotor cavity can only take away the heat of the electric control board that is not overlapped with the limiting structure. Therefore, the heat of the electric control board cannot be well taken away by the water cooling in the rotor cavity, and the electric control board is mainly cooled by natural cooling, and the heat dissipation efficiency of the electric control board is low. In the present technical solution, the heat conduction wall is not easily cracked, the minimum thickness of the heat conduction wall is 0.5 mm, the heat transfer rate of the heat conduction wall is faster, and there is no extra structure between the heat conduction wall and the second end of the pump shaft. The cooling liquid in the rotor cavity can flow through the entire surface of the heat conduction wall located in the rotor cavity, so that the heat of the electric control board can be taken away faster by the liquid cooling in the rotor cavity, and the heat dissipation efficiency of the electric control board is high. Therefore, the present technical solution not only avoids cracking of the heat conduction wall, but also improves the heat dissipation efficiency of the electric control board.

[0017] In the second technical solution and the preferred embodiments, the thickness of the heat conduction wall is between 0.5 mm and 1.5 mm, which further ensures the strength of the heat conduction wall and the heat dissipation efficiency of the electric control board.

[0018] In the third technical solution and the preferred embodiments thereof, the first end of the pump shaft is fixed to the cavity wall of the impeller cavity through the connecting piece. Therefore, when the impeller rotates, the position where the pump shaft is fixed to the shell is very close to the upper part of the rotor. Compared with the prior art in which the position where the pump shaft is fixed to the shell is arranged in the rotor cavity, the deflection deformation of the pump shaft caused by the mass center offset of the rotor and the impeller during the operation of the electric water pump is smaller, the vibration amplitude of the pump shaft caused by the deflection deformation of the pump shaft is smaller, and the noise during the operation of the electric water pump is lower than that of the prior art. In addition, the machining precision of the connecting piece is easier to ensure than that of the upper shell, and the offset between the axis of the pump shaft and the central axis of the impeller cavity is smaller.

[0019] In the fourth technical solution and the preferred embodiments thereof, the connecting piece is made of metal material and is provided with a limiting wall adapted to directly abut against the rotating sleeve. Compared with the scheme in which a gasket is arranged between the connecting piece and the rotating sleeve, the scheme is more conducive to reducing the assembly steps, eliminating the risk of missing, overloading and misalignment, and has a simpler structure.

[0020] In the fifth technical solution and the preferred embodiments thereof, the connecting body for being fixed to the pump shaft is connected to the upper shell through connecting ribs. The connecting ribs are distributed in the circumferential direction, and the interval between the connecting ribs can enable water to smoothly flow into the impeller from the water inlet. The circumferential distribution of the connecting ribs can also ensure the position precision of the connecting body in the impeller cavity, so that the offset between the axis of the pump shaft connected to the connecting body and the central axis of the impeller cavity is smaller, and the operation efficiency of the electric water pump can be effectively improved. The connecting body is sleeved on the first end of the pump shaft and has a bullet head shape as a whole and faces the water inlet. The upper surface of the connecting body is substantially conical or steamed bun-shaped. Such a shape is conducive to reducing the flow resistance of the water flow from the water inlet to the impeller, improving the operation efficiency of the electric water pump, and does not need to consider the matching of two components during machining, has lower machining precision requirements, and has lower overall cost compared with the scheme in which the connecting body and the first end of the pump shaft form a bullet head shape as a whole and face the water inlet.

[0021] In the sixth technical solution and the preferred embodiments thereof, the rotor and the impeller are allowed to axially slide relative to the pump shaft as a whole, so that the rotor and the impeller as a whole are easier to be assembled to the pump shaft. The limiting wall limits the upward movement of the rotor and the impeller as a whole, so that the connecting piece has more functions in addition to connecting the pump shaft, and the structure is simpler. At the same time, since the limiting wall limits the upward movement of the rotor and the impeller as a whole, the fixed position of the pump shaft and the shell is closer to the upper part of the rotor, which is more conducive to inhibiting the deflection deformation of the pump shaft. The lower limiting piece limits the downward movement of the rotor and the impeller, so that the rotor and the impeller will not collide with the connecting piece during rotation due to too long upward travel, which is conducive to reducing noise and increasing service life, and solves the problem that the rotor freely moves along the axial direction of the pump shaft during assembly and is attracted away by the magnetic force.

[0022] In the eighth technical solution and the preferred embodiments thereof, the upper shell is made of plastic material, the connecting piece is integrally formed with the upper shell by insert injection molding, the cost is lower, and the position accuracy of the connecting piece in the impeller cavity can be ensured, so that the deviation between the axis of the pump shaft connected with the connecting body and the central axis of the impeller cavity is smaller, and the operation efficiency of the electric water pump is improved.

[0023] In the ninth technical solution and the preferred embodiments thereof, the upper shell is made of metal material, and the connecting piece is welded with the upper shell, so that the position accuracy of the connecting piece in the impeller cavity can be ensured, and the upper shell made of metal material has higher strength, and the cracking of the upper shell caused by the vibration of the impeller and the rotor being transmitted to the upper shell through the pump shaft can be avoided.

[0024] In the tenth technical solution and the preferred embodiments thereof, the pump shaft is provided with a water passage in the extending direction, the high-pressure area is communicated to the low-pressure area through the rotor cavity and the water passage, the internal circulation cooling flow channel can be established in the electric water pump, the water flows from the high-pressure area to the low-pressure area through the internal circulation cooling flow channel to form an internal circulation cooling water flow, and the heat dissipation of the stator and the control board is facilitated. It should be understood that although the internal circulation cooling water flow may reduce the operation efficiency of the electric water pump, the effective heat dissipation can improve the service life of the electric water pump. The water passage gap is formed between the heat dissipation wall and the rotor, the internal circulation cooling water flow passes through the water passage gap, the heat generated by the stator during the operation of the electric water pump is more easily taken away, and the heat dissipation efficiency of the electric water pump is further improved. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0026] Figure 1 is a top view of the electric water pump of the embodiment of the present application;

[0027] Figure 2 is Figure 1 is a sectional view in the A-A direction;

[0028] Figure 3 is a perspective exploded view of the electric water pump of the embodiment of the present application.

[0029] Explanation of main reference signs:

[0030] Housing 10; upper housing 11; bolt hole 111; middle housing 12; through hole 121; annular groove 122; lower housing 13; insertion part 131; abutting wall 132; heat dissipation wall 14; heat conduction wall 15; impeller cavity 01; rotor cavity 02; electric control cavity 03; water inlet 04; water outlet 05; connecting piece 20; connecting body 21; limiting wall 211; through hole 212; connecting rib 22; embedded part 221; pump shaft 30; water passage 31; impeller 40; rotor 50; rotor part 51; rotating sleeve 52; stator 60; electric control board 70; lower limiting piece 80. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are preferred embodiments of the utility model, and should not be regarded as excluding other embodiments. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the utility model.

[0032] In the claims, the description and the drawings of the utility model, unless otherwise explicitly limited, the terms such as 'first','second' or 'third' are used only to distinguish different objects, and are not used to describe a particular order.

[0033] In the claims, the description and the drawings of the utility model, unless otherwise explicitly limited, for the orientation words, such as the terms 'center', 'transverse', 'longitudinal', 'horizontal','vertical', 'top', 'bottom', 'inner', 'outer', 'upper', 'lower', 'front','rear', 'left', 'right', 'clockwise', 'counterclockwise' indicate the orientation or position relationship based on the orientation and position relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and are not used to indicate or imply that the indicated device or element must have a particular orientation or be constructed and operated in a particular orientation, so it cannot be understood as limiting the specific protection scope of the utility model.

[0034] In the claims, the description and the drawings of the utility model, unless otherwise explicitly limited, such as the terms 'fixedly connected' or 'fixedly connected', should be understood broadly, that is, any connection mode without displacement relationship and relative rotation relationship between the two, that is, it includes irremovable fixed connection, detachable fixed connection, integration and fixed connection through other devices or elements.

[0035] In the claims, the description and the drawings of the utility model, such as the terms 'include', 'have' and their variants, are intended to be 'inclusive but not limited to'.

[0036] In the claims and specification, the term "provided with" means that the technical feature located after it is a part of the technical feature located before it, unless otherwise defined.

[0037] In the claims and specification, the term "stator" includes not only the stator as understood by those of ordinary skill in the art, but also the winding. That is, the stator includes the stator portion and the winding portion.

[0038] In the claims and specification, the term "water-tight" means liquid-tight, which is commonly understood by those of ordinary skill in the art to be achievable by conventional means such as a sealing ring or a sealing cup.

[0039] In the claims and specification, the term "insert injection molding" means a processing means by which the two are tightly combined after injection molding so as to be inseparable, by embedding a part during injection molding.

[0040] In the claims and specification, the term "abut" means that the two are tightly attached or indirectly attached together (for example, through a heat-conductive material).

[0041] Referring to Figures 1-3 , Figures 1-3 An electric water pump is shown, which includes a housing 10, a connecting piece 20, a pump shaft 30, an impeller 40, a brushless motor, an electric control board 70, and a lower limit piece 80.

[0042] As shown in Figure 2 , the housing 10 includes an upper housing 11, a middle housing 12, and a lower housing 13. The upper housing 11 is provided with an impeller cavity 01, a water inlet 04, and a water outlet 05. The impeller cavity 01 is open downward, the water inlet 04 is axially communicated with the top end of the impeller cavity 01, and the water outlet 05 is tangentially communicated with the impeller cavity 01. The middle housing 12 is provided with a rotor cavity 02. The rotor cavity 02 is open upward and is provided with a side cavity wall, and the side cavity wall of the rotor cavity 02 forms a heat dissipation wall 14. The upper housing 11 and the middle housing 12 are water-tightly fixed by a sealing ring and bolts. After the upper housing 11 and the middle housing 12 are fixed, the impeller cavity 01 is axially communicated with the rotor cavity 02. The lower housing 13 and the middle housing 12 are friction-welded and fixed. After the lower housing 13 and the middle housing 12 are fixed, an electric control cavity 03 is enclosed. The electric control cavity 03 is adjacent to the rotor cavity 02 and axially away from the impeller cavity 01. The cavity wall between the rotor cavity 02 and the electric control cavity 03 forms a heat-conductive wall 15. The minimum thickness of the heat-conductive wall 15 is 0.5 mm, and in actual application, the maximum thickness of the heat-conductive wall 15 is 1.5 mm. In this embodiment, the thickness of the heat-conductive wall 15 is 0.9 mm. Therefore, the housing 10 is provided with the water inlet 04, the water outlet 05, the impeller cavity 01, the rotor cavity 02, and the electric control cavity 03.

[0043] As shown in Figures 2-3As shown, the connecting piece 20 is provided with a connecting body 21 and at least two connecting ribs 22, in this embodiment, the number of connecting ribs 22 is four. The connecting body 21 is used to be fixedly connected with the pump shaft 30, the connecting body 21 is in the shape of a downwardly open cylinder, and the bottom of the cylinder is provided with a through hole 212. One end of each connecting rib 22 is fixedly connected with the outer edge of the connecting body 21, and the other end is fixedly connected with the position of the upper shell 11 close to the water inlet 04, that is, the cavity wall of the impeller cavity 01, and each connecting rib 22 is arranged in the circumferential direction. In this embodiment, the end of each connecting rib 22 away from the connecting body 21 is provided with a horizontally extending embedding part 221. In this embodiment, the connecting piece 20 is made of metal material and is provided with a limiting wall 211 directly abutting against the rotating sleeve 52 in the following, and the lower end face of the connecting body 21 forms the limiting wall 211. In one embodiment, the upper shell 11 is made of plastic material, the connecting piece 20 and the upper shell 11 are integrally formed by insert injection molding, and the embedding part 221 is placed in the mold when the connecting piece 20 is injection molded on the upper shell 11, so that the upper shell 11 and the connecting piece 20 are integrally formed by insert injection molding. In another embodiment, the upper shell 11 is made of metal material, and the upper shell 11 is provided with an embedding groove corresponding to each embedding part 221, the embedding part 221 is inserted into the embedding groove and welded with the upper shell 11, so that the connecting piece 20 is welded with the upper shell 11.

[0044] As shown in the drawings, Figure 2 As shown, the first end of the pump shaft 30 is located in the impeller cavity 01 and axially faces the water inlet 04, and the second end of the pump shaft 30 is located in the rotor cavity 02 and is suspended on the heat conducting wall 15. In this embodiment, the pump shaft 30 is inserted into the cylinder formed by the connecting body 21 and abuts against the bottom of the cylinder, and the pump shaft 30 can be fixedly connected with the connecting body 21 by interference fit, or can be fixedly connected with the connecting body 21 by other ways such as adhesion, screwing, embedding and the like, which are well known to those skilled in the art. Therefore, in this embodiment, the pump shaft 30 is fixed relative to the shell 10. The pump shaft 30 is provided with a water passage 31 penetrating through the entire pump shaft 30 along the extension direction of the pump shaft 30, and the water passage 31 is in communication with the through hole 212. Therefore, the first end of the pump shaft 30 is fixedly connected with the cavity wall of the impeller cavity 01 through the connecting piece 20, and in this embodiment, the first end of the pump shaft 30 is fixedly connected with the connecting body 21, and the fixedly connected position is located in the impeller cavity 01. In other embodiments, the connecting body 21 can be fixedly connected with the part of the pump shaft 30 other than the first end and located in the impeller cavity 01. In this embodiment, the connecting body 21 is sleeved on the first end of the pump shaft 30 and has a bullet head shape facing the water inlet 04, and the upper surface thereof is substantially in the shape of a cone or a steamed bun. Such a shape is beneficial to reduce the flow resistance of the water flow from the water inlet 04 to the impeller 40. In this embodiment, the pump shaft 30 can be made of plastic material or metal material.

[0045] As shown in the drawings, Figure 2As shown, the impeller 40 rotates in the impeller cavity 01 about the rotation axis defined by the pump shaft 30 relative to the pump shaft 30. The electric water pump outputs the water flow or liquid flow input from the water inlet 04 to the water outlet 05 by the rotation of the impeller 40. In this embodiment, when the impeller 40 rotates in the impeller cavity 01, a high pressure area is formed between the impeller 40 and the cavity wall of the impeller cavity 01. Specifically, a gap is formed between the outer edge of the impeller 40 and the side cavity wall of the impeller cavity 01, and the gap forms the high pressure area. Correspondingly, when the impeller 40 rotates in the impeller cavity 01, a low pressure area is formed in the area close to the water inlet 04. When the electric water pump is used to establish a circulating water flow, the rotation of the impeller 40 causes the pressure of the water outlet 05 to be higher than the pressure of the water inlet 04, so that the circulating water pump pumps the outlet flow from the water outlet 05 back to the water inlet 04.

[0046] As shown in Figure 2 The brushless motor includes a stator 60 and a rotor 50. The stator 60 includes a stator portion and a winding portion, and is fixedly connected to the middle shell 12 and surrounds the outside of the rotor cavity 02. The middle shell 12 also wraps the outside of the stator 60. The stator 60 is water-tightly isolated from the rotor cavity 02. The rotor 50 is located in the rotor cavity 02 and is rotationally connected to the pump shaft 30. The rotor 50 is sleeved on the pump shaft 30. In this embodiment, the rotor 50 includes a rotor portion 51 and a rotating sleeve 52 which are fixedly connected to each other. The rotor portion 51 and the stator 60 jointly constitute the brushless motor, and the rotor portion 51 generally adopts a permanent magnet. The rotating sleeve 52 is sleeved on the pump shaft 30 and is in gap fit with the pump shaft 30. The rotor portion 51 is sleeved outside the rotating sleeve 52, and the rotating sleeve 52 is located between the pump shaft 30 and the rotor portion 51. In this embodiment, the rotating sleeve 52 is made of stainless steel.

[0047] As shown in Figure 2 The rotor 50 and the heat dissipation wall 14 form a water passing gap for connecting the high pressure area and the water passing channel 31. In this embodiment, the rotor 50 is fixedly connected to the impeller 40, so that the brushless motor can drive the impeller 40 to rotate in the impeller cavity 01 about the pump shaft 30. In this embodiment, the whole formed by the rotor 50 and the impeller 40 is allowed to axially slide relative to the pump shaft 30, and is also allowed to rotate about the rotation axis relative to the pump shaft 30. In this embodiment, the connecting piece 20 is located above the rotating sleeve 52, and the limiting wall 211 is used to limit the upward movement of the whole formed by the rotor 50 and the impeller 40. Specifically, when the impeller 40 rotates, the impeller 40 will drive the rotor 50 to move upward together until the rotating sleeve 52 directly or indirectly abuts against the limiting wall 211 of the connecting piece 20.

[0048] As shown in Figure 2As shown, the electric control board 70 is installed in the electric control cavity 03 and electrically connected with the stator 60 to control the stator 60, so that the brushless motor can be started, stopped and the rotating speed adjusted. In this embodiment, the electric control board 70 is attached to the heat-conducting wall 15 through heat-conducting silica gel. The electric control board 70 is also connected with external terminals through lead wires penetrating the lower shell 13 to obtain external power and control signals, which is well known to those skilled in the art.

[0049] As shown, the lower limit member 80 is a snap spring, which is clamped on the pump shaft 30 to be fixedly connected with the pump shaft 30. The lower limit member 80 is used to limit the downward movement of the whole formed by the rotor 50 and the impeller 40. Figure 2

[0050] In the operation process of the electric water pump in this embodiment, the main water flow and the internal circulation cooling water flow are formed. The main water flow is consistent with the prior art, as described above, the high pressure area is formed between the impeller 40 and the cavity wall of the impeller cavity 01 during the rotation of the impeller 40, the high pressure area is connected to the low pressure area near the water inlet 04 through the rotor cavity 02 and the water passage 31, and the water flow flows from the high pressure area to the low pressure area through the water passage gap, the rotor cavity 02 and the water passage 31 and merges with the main water flow. The low pressure area is located near the water inlet 04, thereby forming the internal circulation cooling water flow, but the internal circulation cooling water flow exchanges liquid with the main water flow, as described above, since the stator 60 is arranged outside the rotor cavity 02, and generally the stator 60 is adjacent to or attached to the heat-dissipating wall 14, therefore, the water flow passing through the water passage gap can take away the heat generated by the stator 60 during the operation of the electric water pump. As described above, the heat generated by the electric control board 70 during the operation process can be transferred to the heat-conducting wall 15, and the water flow about to enter the second end of the pump shaft 30 can take away the heat.

[0051] Generally, when the electric water pump is assembled, the stator 60 and the middle shell 12 are integrally formed by insert injection molding, the rotor 50 is placed in the middle shell 12, and then the upper shell 11 and the middle shell 12 are water-tightly and fixedly connected, and the electric control board 70 is assembled from the opening of the middle shell 12 away from the upper shell 11, and then the lower shell 13 is water-tightly and fixedly connected with the middle shell 12, that is, the direction of the shell 10 needs to be adjusted during assembly, which brings inconvenience to the on-site workers. In this embodiment, in order to improve this problem, as shown in Figures 2-3 ​As shown, the upper shell 11 is provided with a bolt hole 111 for bolt fixation, which is open to the lower shell 13, and the middle shell 12 is provided with a through hole 121 corresponding to the bolt hole 111, so that when installed, the insertion direction of the electric control board 70 and the insertion direction of the bolt are consistent, facilitating installation. In this embodiment, in order to facilitate installation, an annular groove 122 is arranged on the side of the middle shell 12 close to the opening of the lower shell 13, and the lower shell 13 is provided with an insertion portion 131 which can be inserted into the annular groove 122 and an abutting wall 132 which abuts against the end of the groove wall of the annular groove 122, and the insertion portion 131 and the annular groove 122 can be welded together by friction welding process. Compared with the welding scheme by sealing ring and screw, not only the number of parts can be reduced, but also the outer diameter of the lower shell 13 can be reduced. Compared with the laser welding process, the lower shell 13 does not need to have light transmission and will not produce splashes. Compared with the ultrasonic welding process, high frequency vibration is not needed, and the destructiveness to the product is smaller.

[0052] In this embodiment, since the second end of the pump shaft 30 is located in the rotor cavity 02 and is suspended in the heat-conducting wall 15, the rotation of the rotor 50 and the impeller 40 is not easily transmitted to the heat-conducting wall 15 through the pump shaft 30, and the heat-conducting wall 15 is not easily cracked. In the prior art, in order to avoid cracking of the heat-conducting wall 15, the heat-conducting wall 15 is often thickened, and a limiting structure is often protruded on the heat-conducting wall 15 to cooperate with the second end of the pump shaft 30. In this way, after the electric control board 70 is attached to the heat-conducting plate, since the heat-conducting wall 15 is thick, the heat of the electric control board 70 cannot be well transmitted to the side of the heat-conducting wall 15 located in the rotor cavity 02. Moreover, the protruding limiting structure on the heat-conducting wall 15 occupies space in the rotor cavity 02 and is often located at the center of the heat-conducting wall 15. The coolant in the rotor cavity 02 can only flow around the limiting structure, and only the heat of the electric control board 70 which is not overlapped with the limiting structure can be taken away by the coolant in the rotor cavity 02. Therefore, the heat of the electric control board 70 cannot be well taken away by the water cooling in the rotor cavity 02, and the electric control board 70 is mainly cooled by natural cooling, resulting in low cooling efficiency of the electric control board 70. In this technical solution, the heat-conducting wall 15 is not easily cracked, the minimum thickness of the heat-conducting wall 15 is 0.5 mm, the heat transfer rate of the heat-conducting wall 15 is faster, and there is no extra structure between the heat-conducting wall 15 and the second end of the pump shaft 30. The coolant in the rotor cavity 02 can flow through the entire surface of the heat-conducting wall 15 located in the rotor cavity 02, so that the heat of the electric control board 70 can be taken away by the liquid cooling in the rotor cavity 02 faster, and the cooling efficiency of the electric control board 70 is high. Therefore, this technical solution not only avoids cracking of the heat-conducting wall 15, but also improves the cooling efficiency of the electric control board 70.

[0053] In this embodiment, the thickness of the heat-conducting wall 15 is between 0.5 mm and 1.5 mm, further ensuring the strength of the heat-conducting wall 15 and the cooling efficiency of the electric control board 70.

[0054] In the embodiment, the first end of the pump shaft 30 is fixed to the cavity wall of the impeller cavity 01 through the connecting piece 20, so that when the impeller 40 rotates, the position where the pump shaft 30 is fixed to the shell 10 is very close to the upper part of the rotor 50. Compared with the prior art in which the position where the pump shaft 30 is fixed to the shell 10 is arranged in the rotor cavity 02, the deflection of the pump shaft 30 caused by the mass center offset of the rotor 50 and the impeller 40 during the operation of the electric water pump is smaller, the vibration amplitude of the pump shaft 30 caused by the deflection of the pump shaft 30 is smaller, and the noise during the operation of the electric water pump is lower than that of the prior art. In addition, the machining precision of the connecting piece 20 is easier to ensure than that of the upper shell 11, and the offset between the axis of the pump shaft 30 and the central axis of the impeller cavity 01 is smaller.

[0055] In the embodiment, the connecting piece 20 is made of metal material and is provided with a limiting wall 211 adapted to directly abut against the rotating sleeve 52. Compared with the scheme in which a gasket is arranged between the connecting piece 20 and the rotating sleeve 52, the scheme is more conducive to reducing the assembly steps, eliminating the risk of missing, overloading and misalignment, and the structure is simpler.

[0056] In the embodiment, the connecting body 21 for being fixed to the pump shaft 30 is connected to the upper shell 11 through the connecting ribs 22. The connecting ribs 22 are distributed in the circumferential direction, and the interval between the connecting ribs 22 can make the water flow smoothly from the water inlet 04 to the impeller 40. The circumferential distribution of each connecting rib 22 can also ensure the position accuracy of the connecting body 21 in the impeller cavity 01, so that the offset between the axis of the pump shaft 30 connected to the connecting body 21 and the central axis of the impeller cavity 01 is smaller, and the operation efficiency of the electric water pump can be effectively improved. The connecting body 21 is sleeved on the first end of the pump shaft 30 and has a bullet head shape as a whole toward the water inlet 04, and the upper surface thereof is substantially conical or steamed bun-shaped. Such a shape is conducive to reducing the flow resistance of the water flow from the water inlet 04 to the impeller 40, improving the operation efficiency of the electric water pump, and compared with the scheme in which the connecting body 21 and the first end of the pump shaft 30 are matched to form a bullet head shape as a whole toward the water inlet 04, the matching of the two components does not need to be considered during machining, the machining precision requirement is lower, and the overall cost is lower.

[0057] In the embodiment, the rotor 50 and the impeller 40 are allowed to slide axially relative to the pump shaft 30 as a whole, so that the rotor 50 and the impeller 40 as a whole are more easily assembled to the pump shaft 30. The limiting wall 211 limits the upward movement of the rotor 50 and the impeller 40 as a whole, so that the connecting piece 20 has more functions in addition to connecting the pump shaft 30, and the structure is simpler. At the same time, since the limiting wall 211 limits the upward movement of the rotor 50 and the impeller 40 as a whole, the position of the pump shaft 30 fixed to the shell 10 is closer to the upper part of the rotor 50, which is more conducive to inhibiting the deflection of the pump shaft 30. The lower limiting piece 80 limits the downward movement of the rotor 50 and the impeller 40, so that the rotor 50 and the impeller 40 will not hit the connecting piece 20 due to too long upward stroke during rotation, which is conducive to reducing noise and increasing service life, and at the same time solves the problem that the rotor 50 freely moving axially along the pump shaft 30 during assembly will be attracted away by magnetic force.

[0058] In the embodiment, the upper shell 11 is made of plastic material, the connecting piece 20 and the upper shell 11 are integrally formed by insert injection molding, which is lower in cost and can better ensure the position accuracy of the connecting piece 20 in the impeller cavity 01, so that the axis of the pump shaft 30 connected with the connecting body 21 deviates less from the central axis of the impeller cavity 01, which is conducive to improving the operating efficiency of the electric water pump. In other embodiments, the upper shell 11 is made of metal material, and the connecting piece 20 is welded with the upper shell 11, which can not only ensure the position accuracy of the connecting piece 20 in the impeller cavity 01, but also the upper shell 11 made of metal material has higher strength, which is more conducive to avoiding the cracking of the upper shell 11 caused by the vibration of the impeller 40 and the rotor 50 being transmitted to the upper shell 11 through the pump shaft 30.

[0059] In the embodiment, the pump shaft 30 is provided with a water passage 31 in the extending direction, and the high-pressure area is communicated to the low-pressure area through the rotor cavity 02 and the water passage 31, so that an internal circulation cooling flow channel is established inside the electric water pump, water flows from the high-pressure area to the low-pressure area through the internal circulation cooling flow channel to form an internal circulation cooling water flow, which is conducive to heat dissipation of the stator 60 and the control board 70. It should be understood that although the internal circulation cooling water flow may reduce the operating efficiency of the electric water pump, effective heat dissipation can improve the service life of the electric water pump. The water passage gap is formed between the heat dissipation wall 14 and the rotor 50, and the internal circulation cooling water flow passes through the water passage gap, which is more conducive to taking away the heat generated by the stator 60 during operation of the electric water pump, further improving the heat dissipation efficiency of the electric water pump.

[0060] The description of the above specification and the embodiments are used to explain the protection scope of the present application, but do not constitute the limitation of the protection scope of the present application. Through the inspiration of the present application or the above embodiments, the ordinary skilled in the art combines the common knowledge, the ordinary technical knowledge in the art and / or the prior art, and obtains the modification, equivalent replacement or other improvement of the present application embodiment or one part of the technical features through logical analysis, reasoning or limited test, which should be included in the protection scope of the present application.

Claims

1. An electric water pump, characterized in that, include The housing (10) is provided with an inlet (04), an outlet (05), an impeller cavity (01), a rotor cavity (02), and an electrical control cavity (03); the inlet (04) and the outlet (05) are connected to the impeller cavity (01), and the rotor cavity (02) is axially connected to the impeller cavity (01); the electrical control cavity (03) is adjacent to the rotor cavity (02) and axially away from the impeller cavity (01); the cavity wall between the electrical control cavity (03) and the rotor cavity (02) forms a heat-conducting wall (15), and the minimum thickness of the heat-conducting wall (15) is 0.5 mm; A pump shaft (30) has its first end located in the impeller cavity (01) and its second end located in the rotor cavity (02) and suspended above the heat-conducting wall (15); a brushless motor includes a rotor (50) and a stator (60), wherein the rotor (50) is located in the rotor cavity (02) and is rotatably connected to the pump shaft (30); the stator (60) is fixed to the housing (10) and surrounds the rotor cavity (02); Impeller (40), which is located in impeller cavity (01) and fixedly connected to the rotor (50); and An electrical control board (70) is installed in the electrical control cavity (03) and electrically connected to the stator (60) to control the stator (60). The electrical control board (70) is attached to the heat-conducting wall (15).

2. The electric water pump as described in claim 1, characterized in that, The maximum thickness of the heat-conducting wall (15) is 1.5 mm.

3. The electric water pump as described in claim 1, characterized in that, It also includes a connector (20); the first end of the pump shaft (30) is fixed to the cavity wall of the impeller cavity (01) through the connector (20).

4. An electric water pump as described in claim 3, characterized in that, The rotor (50) includes a rotating sleeve (52) and a rotor part (51) fixedly connected to each other. The rotating sleeve (52) is sleeved on the pump shaft (30) and has a clearance fit with the pump shaft (30). The rotor part (51) is sleeved outside the rotating sleeve (52). The connecting member (20) is made of metal and has a limiting wall (211) suitable for direct contact with the rotating sleeve (52).

5. An electric water pump as described in claim 4, characterized in that, The connector (20) is provided with a connector (21) and at least two connecting ribs (22). The connector (21) is sleeved on the first end of the pump shaft (30) and is bullet-shaped facing the water inlet (04). One end of the connecting rib (22) is fixed to the connector (21), and the other end is fixed to the cavity wall of the impeller cavity (01). Each connecting rib (22) is arranged circumferentially. The lower end face of the connector (21) forms the limiting wall (211).

6. An electric water pump as described in claim 4, characterized in that, It also includes a lower limiting member (80); the rotor (50) and the impeller (40) are allowed to slide axially relative to the pump shaft (30), and the limiting wall (211) limits the upward movement of the rotor (50) and the impeller (40); the lower limiting member (80) is fixed to the pump shaft (30) and is used to limit the downward movement of the rotor (50) and the impeller (40).

7. An electric water pump as described in any one of claims 4-6, characterized in that, The housing (10) includes an upper housing (11), a middle housing (12) and a lower housing (13). The upper housing (11) is watertightly connected to the middle housing (12), and the lower housing (13) is fixedly connected to the middle housing (12). The impeller cavity (01), the inlet (04) and the outlet (05) are formed in the upper housing (11), and the rotor cavity (02) is formed in the middle housing (12). The middle housing (12) and the lower housing (13) together form the electrical control cavity (03).

8. An electric water pump as described in claim 7, characterized in that, The upper housing (11) is made of plastic, and the connector (20) and the upper housing (11) insert are integrally injection molded.

9. An electric water pump as described in claim 7, characterized in that, The upper housing (11) is made of metal, and the connector (20) is welded to the upper housing (11).

10. An electric water pump as described in claim 7, characterized in that, The pump shaft (30) is provided with a water passage (31) along its extension direction. A high-pressure zone is formed between the impeller (40) and the cavity wall of the impeller cavity (01). The high-pressure zone is connected to a low-pressure zone near the inlet (04) through the rotor cavity (02) and the water passage (31). A heat dissipation wall (14) is formed on the side cavity wall of the rotor cavity (02). A water passage gap is formed between the heat dissipation wall (14) and the rotor (50). The water passage gap is used to connect the high-pressure zone and the water passage (31).

Images