Electric liquid pump

Abstract

To provide a technique capable of reducing the manufacturing costs of an electric liquid pump and the weight of the electric liquid pump.SOLUTION: An electric liquid pump 1 comprises: an electric motor 2 having a motor rotor 20 and a stator 25; a liquid pump 3 having an inner rotor 30 and an outer rotor 35; a motor case 4 formed into a box-shape, and having therein a first housing chamber 41 housing the stator 25, a second housing chamber 42 housing another axial part of the motor rotor 20, and a partition wall 45; and a body 5 having a bearing part supporting one axial part of the shaft 21. In the shaft 21, a large-diameter sleeve 21s at one axial end and a general shaft part 21g serving as a remaining axial part and having a smaller diameter than that of the sleeve 21s are integrally molded of the same material. The magnet part 23 is made of a bond magnet, and integrated with the sleeve 21s.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electric fluid pump for transporting fluids such as oil. [Background technology]

[0002] A known electric liquid pump for transporting liquids such as oil includes an electric motor as a driving source, and an inner rotor and an outer rotor connected to the shaft of the electric motor to realize the pump function (see, for example, Patent Document 1).

[0003] In this type of electric liquid pump, the rotation of the motor rotor of the electric motor rotates the inner rotor, which is integrated with the shaft of the motor rotor. The rotation of the inner rotor also rotates the outer rotor, which is meshed with the inner rotor. This allows the pump to function as a pump that sucks in and discharges liquid. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-101062 Summary of the Invention [Problem to be solved by the invention]

[0005] The motor rotor in the electric liquid pump has a magnet portion integrated with one axial end of a shaft.

[0006] In a typical motor rotor, the shaft and magnet portion are both made of metal, and such a conventional motor rotor has a large mass and a large rotational torque due to the metal shaft and metal magnet portion.

[0007] Therefore, conventional electric liquid pumps having the above-described conventional motor rotor in an electric motor require a bearing portion including a metal bearing as a bearing for stably supporting the motor rotor. A bearing is a mechanism for smoothly rotating a shaft. For example, a typical rolling bearing has a three-layer structure consisting of an inner ring, balls, and an outer ring, and is a component with a relatively large mass.

[0008] Therefore, it is difficult to reduce the weight of such conventional electric liquid pumps.

[0009] Patent Document 1 introduces a technology that uses a bonded magnet as the magnet portion of a motor rotor. A bonded magnet is a magnet made by binding magnetic powder with a binder, and by using a bonded magnet as the magnet part, it is possible to reduce the mass of the magnet part by the amount of the binder.

[0010] Patent Document 1 also proposes providing a large-diameter sleeve on a portion of the shaft of the motor rotor in the axial direction, and integrating a magnet portion with the surface of the sleeve, including the outer peripheral surface.

[0011] A motor rotor having a large-diameter sleeve on the shaft allows the magnet section to be made smaller by the size of the sleeve, and the sleeve can function as a back yoke for the magnet section, thereby giving the electric motor excellent functionality.

[0012] However, a motor rotor in which the magnet portion is integrated into the sleeve requires a complicated manufacturing process. For example, in Patent Document 1, a shaft is press-fitted and fixed into a sleeve having an opening in the center, and then a magnet portion made of a bonded magnet is integrally molded on the outer periphery of the sleeve in the integrated shaft-sleeve assembly.

[0013] Therefore, in conventional electric liquid pumps, the rotor motor is made up of a large number of parts, and the rotor motor requires a large number of steps to manufacture, which makes the manufacturing process complicated and makes it difficult to reduce manufacturing costs.

[0014] The present invention has been made in view of the above circumstances, and an object to be achieved is to provide a technique that can reduce the manufacturing cost of an electric liquid pump and make the electric liquid pump lighter. [Means for solving the problem]

[0015] One aspect of the electric liquid pump of the present invention that solves the above problem is: an electric motor including a motor rotor having a shaft and a magnet portion integrated with one axial end of the shaft, and a stator disposed radially outside or inside the magnet portion to rotate the motor rotor; a liquid pump including: an inner rotor having external teeth and integral with the other axial end of the shaft; and an outer rotor having internal teeth that mesh with the external teeth and forming a clearance volume between the inner rotor and the outer rotor, into which liquid is sucked from a suction passage and into which liquid is discharged toward a discharge passage; a motor case having a box shape and including inside a first accommodating chamber that accommodates the stator and a portion of the motor rotor in the axial direction including the magnet portion, a second accommodating chamber that communicates with the first accommodating chamber and accommodates another portion of the motor rotor in the axial direction, and a partition wall that has a hole-like communicating portion that communicates the first accommodating chamber and the second accommodating chamber and is provided between the first accommodating chamber and the second accommodating chamber, and in which a liquid circulates between the first accommodating chamber, the second accommodating chamber, and the hole-like communicating portion; a body including a centering body portion inserted into the hole-like connecting portion and centered therein, a general body portion continuous with the centering body portion and accommodated in the second accommodation chamber, and a bearing portion formed through the centering body portion and the general body portion and supporting a part of the axial direction of the shaft at a position between the magnet portion and the inner rotor, the shaft is formed by integrally molding a large-diameter sleeve, which is the one end in the axial direction, and a general shaft portion, which is the remaining portion in the axial direction and has a smaller diameter than the sleeve, from the same material; The magnet portion is made of a bonded magnet and is integrated with the outer or inner peripheral surface of the sleeve, making it an electric liquid pump.

[0016] Another aspect of the electric liquid pump of the present invention that solves the above problem is: an electric motor including a motor rotor having a shaft and a magnet portion integrated with one axial end of the shaft, and a stator disposed radially outside or inside the magnet portion to rotate the motor rotor; a liquid pump including: an inner rotor having external teeth and integral with the other axial end of the shaft; and an outer rotor having internal teeth that mesh with the external teeth and forming a clearance volume between the inner rotor and the outer rotor, into which liquid is sucked from a suction passage and into which liquid is discharged toward a discharge passage; a box-shaped case that houses the liquid pump and the shaft; the shaft is formed by integrally molding a large-diameter sleeve, which is the one end in the axial direction, and a general shaft portion, which is the remaining portion in the axial direction and has a smaller diameter than the sleeve, from the same material; The magnet portion is made of a bonded magnet and is integrated with the outer or inner peripheral surface of the sleeve, making it an electric liquid pump. [Effects of the Invention]

[0017] The technology of the present invention can reduce the manufacturing cost of an electric liquid pump and the weight of the electric liquid pump. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is an explanatory diagram for schematically explaining the appearance of an electric liquid pump according to a first embodiment. [Figure 2] 2 is an explanatory diagram for explaining a schematic view of the electric liquid pump of the first embodiment cut at the position XX in FIG. 1. FIG. [Figure 3]2 is an explanatory diagram for schematically explaining the electric liquid pump of the first embodiment cut at the YY position in FIG. 1. FIG. [Figure 4] 10A and 10B are explanatory diagrams illustrating another example of a motor rotor in the electric liquid pump of the present invention. [Figure 5] 10A and 10B are explanatory diagrams illustrating another example of a motor rotor in the electric liquid pump of the present invention. [Figure 6] 10A and 10B are explanatory diagrams illustrating another example of a motor rotor in the electric liquid pump of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] The electric liquid pump of the present invention will be described below by way of a specific example.

[0020] As mentioned above, when a conventional electric liquid pump has a motor rotor with a large-diameter sleeve attached to its shaft, the shaft and sleeve are integrated by press-fitting the shaft into the sleeve. This process is complicated and places a burden on the worker, making it expensive to manufacture this type of motor rotor, and making it difficult to reduce the manufacturing cost of the electric liquid pump.

[0021] The electric fluid pump of the present invention also has a shaft formed by a general shaft portion and a sleeve having a diameter larger than that of the general shaft portion, and the sleeve and the general shaft portion are integrally molded from the same material. As a result, the electric liquid pump of the present invention does not require the step of press-fitting the shaft into the sleeve during the manufacture of the motor rotor, and does not impose a burden on the worker, which has the advantage of reducing manufacturing costs.

[0022] In the electric liquid pump of the present invention, the magnet portion integrated with the sleeve of the motor rotor is made of a bonded magnet.

[0023] As mentioned above, the magnet part made of a bonded magnet is lighter than the magnet part made of metal by the weight of the binder. Therefore, according to the electric liquid pump of the present invention, in which the magnet portion is made of a bonded magnet, the weight of the motor rotor can be reduced.

[0024] Furthermore, since the motor rotor is lightweight, its rotational torque is also small. Therefore, the electric liquid pump of the present invention can smoothly rotate the shaft without using metal bearings. As a result, the electric liquid pump of the present invention can be made even lighter.

[0025] By virtue of these cooperation, the electric liquid pump of the present invention is lightweight and can be manufactured at low cost.

[0026] The electric liquid pump of the present invention will be described below with respect to each of its components. In this specification, when simply referring to the radial direction or the axial direction, it means the radial direction or the axial direction of the shaft of the electric motor.

[0027] Unless otherwise specified, the numerical ranges "x to y" described in this specification include the lower limit x and the upper limit y. These upper and lower limit values, as well as the numerical values ​​listed in the embodiments, can be arbitrarily combined to form a numerical range. Furthermore, the upper and lower limit values ​​can be arbitrarily selected from within the numerical range.

[0028] The electric fluid pump of the present invention is a pump for infusing fluids such as oil and various coolants, and can be embodied, for example, as a pump mounted on a vehicle to supply oil to a drive system such as a transmission. The electric fluid pump of the present invention may be a small pump mounted on a vehicle, or a stationary pump installed in various facilities.

[0029] The electric liquid pump of the present invention comprises an electric motor, a liquid pump, and a case, the case of which may comprise a motor case and a body.

[0030] The electric motor includes a shaft, a magnet, and a stator. The electric motor in the electric liquid pump of the present invention may be a so-called inner rotor motor in which the stator is disposed radially outside the motor rotor, or a so-called outer rotor motor in which the stator is disposed radially inside the motor rotor.

[0031] The shaft is a long member that constitutes the rotating shaft of the motor rotor, and it is preferable to use a material that is difficult to deform as the material for the shaft.

[0032] The shaft may be made of a magnetic material or a non-magnetic material, but is preferably made of a magnetic material in order to function as a back yoke for the magnet portion.

[0033] As a material for the shaft, for example, stainless steel is preferably used. Examples of stainless steel include austenitic stainless steels such as SUS303, SUS304, and SUS316, ferritic stainless steels such as SUS430, and martensitic stainless steels such as SUS410 and SUS440C. Of these, SUS303, an austenitic stainless steel, is particularly suitable as a material for the shaft due to its excellent corrosion resistance.

[0034] The shaft has a general shaft portion and a sleeve, which are integrally molded. The method for integrally molding the general shaft portion and the sleeve may be selected from general methods such as forging, press molding, casting, etc.

[0035] The shaft of the electric liquid pump of the present invention has a sleeve at one axial end, i.e., at the portion integrated with the magnet portion, which has a larger diameter than the other portions.

[0036] The shape of the sleeve is not particularly limited, and may be, for example, plate-like, columnar, box-like, etc. Because the motor rotor is a rotor, the sleeve, which is part of the motor rotor, preferably has a shape that can reduce rotational torque, specifically a shape that is uniform or approximately uniform in the circumferential direction of the shaft. For example, it is particularly preferable that the sleeve be a perfect circle or a regular polygon in a projection of the shaft in the axial direction.

[0037] Considering the need to integrate the sleeve and the magnet portion with high adhesion, it is preferable that the side surface of the magnet that is integrated with the magnet in the sleeve has an uneven shape, such as a rough surface. Alternatively, a primer layer that has excellent compatibility with the magnet portion may be formed on the magnet side surface. The material of the primer layer can be selected appropriately depending on the binder used in the magnet portion.

[0038] The thickness of the sleeve, i.e., the axial length of the sleeve, may or may not be constant in the radial direction. For example, the thickness of the sleeve may be greater at the center, i.e., the shaft side, than at the peripheral side. Alternatively, the thickness of the sleeve may be greater at the peripheral side than at the shaft side.

[0039] Furthermore, as will be described later, when the case of the electric liquid pump of the present invention has a motor case and a body, and liquid circulates inside the motor case, the liquid also reaches the motor rotor. Therefore, in this case, in order to promote the circulation of the liquid, a groove that serves as a flow path for the liquid may be provided in the sleeve.

[0040] The shape of the grooves is not particularly limited, but it is preferable that the sleeve has multiple grooves extending radially from the inside to the outside in the radial direction. Liquid that has entered the grooves of such a sleeve flows from the inside to the outside in the radial direction of the sleeve as the motor rotor rotates. This allows the liquid to circulate quickly inside the motor case.

[0041] The magnet part is made of bonded magnet.

[0042] As mentioned above, a bonded magnet is a magnet made by binding magnetic powder with a binder. The magnetic powder may be any known material such as SmFeN, ferrite, or neodymium. The binder is not particularly limited, and known binders such as resins and elastomers may be used.

[0043] The magnet part is not the part of the motor rotor that comes into contact with other components. Therefore, the magnet part does not require much sliding property or wear resistance. For this reason, a thermoplastic resin such as polyamide (PA) can be preferably used as a binder for the magnet part.

[0044] The method for integrating the magnet part and the shaft is not particularly limited, and for example, the magnet part may be integrated with the shaft as an insert during molding by insert molding, etc. Alternatively, a pre-molded magnet part may be fixed to the shaft using a method such as adhesion.

[0045] The magnet portion may be integrated with the sleeve. For example, the magnet portion may be integrated with the outer or inner circumferential surface of the sleeve, or may be embedded inside the sleeve to be integrated with the sleeve. Note that it is particularly preferable to position the magnet portion on the sleeve close to the stator, and specifically, it is particularly preferable to integrate the magnet portion on the surface of the sleeve facing the stator. That is, if the electric motor in the electric liquid pump of the present invention is a so-called inner rotor motor in which the stator is disposed radially outside the motor rotor, it is preferable to integrate the magnet part with the outer circumferential surface of the sleeve of the motor rotor or a position close to said outer circumferential surface.Also, if the electric motor is a so-called outer rotor motor in which the stator is disposed radially inside the motor rotor, it is preferable to integrate the magnet part with the inner circumferential surface of the sleeve of the motor rotor or a position close to said inner circumferential surface.

[0046] In addition to these, the magnet portion may be integrated with another portion of the sleeve. The other portion may be, for example, one or the other axial end surface of the sleeve. The magnet portion integrated with the other portion and the magnet portion integrated with the outer or inner circumferential surface of the sleeve may be separate bodies, but considering the adhesion between the sleeve and the magnet portion and the manufacturing man-hours, it is preferable that they are integrated.

[0047] The stator is a part that generates a force for rotating the rotor, and may have a known structure such as a core with a coil wound around it.

[0048] The liquid pump has an inner rotor and an outer rotor.

[0049] The inner rotor has external teeth and is integrated with the other axial end of the shaft, more specifically, the other end of the general shaft portion of the shaft, so that the inner rotor rotates together with the shaft.

[0050] The outer rotor has internal teeth that mesh with the external teeth of the inner rotor. In other words, the inner rotor is disposed inside the outer rotor, and the outer rotor rotates in response to the rotation of the inner rotor.

[0051] A clearance volume is formed between the inner rotor and the outer rotor. As the inner rotor and the outer rotor rotate, liquid is drawn into the clearance volume from a suction passage outside the electric liquid pump, and liquid is discharged from the clearance volume to a discharge passage outside the electric liquid pump.

[0052] The inner rotor and outer rotor for forming the clearance volume may have any shape that is generally used in liquid pumps.

[0053] Specifically, in a typical oil pump, the inner rotor and outer rotor mesh eccentrically. The inner rotor has multiple external teeth. The outer rotor is located radially outward of the inner rotor and has internal teeth that mesh with the external teeth of the inner rotor. The number of internal teeth on the outer rotor is different from the number of external teeth on the inner rotor. When the shaft rotates, the inner rotor, which is integrated with the shaft, rotates integrally with the shaft. This causes the outer rotor, which is engaged with the inner rotor, to rotate eccentrically relative to the inner rotor. As this rotation occurs, the volumes of the multiple clearance volumes formed between the inner rotor and the outer rotor repeatedly shrink and expand sequentially. This causes oil to be sucked up from the suction passage outside the electric hydraulic pump to the clearance volumes by negative pressure, and oil to be compressed from the clearance volumes to the discharge passage outside the electric hydraulic pump by compression.

[0054] The inner rotor and the outer rotor may have any general shape that can perform the above-mentioned pump function.

[0055] In the electric liquid pump of the present invention, the material of the inner rotor and the outer rotor is not particularly limited, and they may be made of metal such as aluminum, or may be made of resin. At least one of the inner rotor and the outer rotor is preferably made of resin, and is particularly preferably made of a thermosetting resin. Hereinafter, the inner rotor or the outer rotor that is made of resin may be referred to as a resin rotor, as necessary.

[0056] The resin rotor is lightweight because it is made of resin material. Another advantage of a resin rotor is that it can be manufactured easily and inexpensively. Therefore, when at least one of the inner rotor and the outer rotor is a resin rotor, the electric liquid pump of the present invention can be made even lighter, and the manufacturing cost of the electric liquid pump of the present invention can be reduced.

[0057] By using a thermosetting resin as the material for the resin rotor, it is possible to reduce the manufacturing cost while maintaining the heat resistance of the resin rotor, and further to reduce the weight of the resin rotor, which is the inner rotor and / or outer rotor.

[0058] The inner rotor and the outer rotor may be made of the same or different materials. The inner rotor and the outer rotor are preferably made of resin. Thermosetting resins that can be used as the material for the inner rotor and the outer rotor will be described in detail later.

[0059] The case may be any type that is box-shaped and can accommodate the liquid pump and shaft described above, but it is preferable that the case be equipped with the motor case and body described below.

[0060] The motor case is a box-shaped member that houses the motor rotor having a magnet portion, the stator, and the body.

[0061] The motor case has a first housing chamber and a second housing chamber therein, and a partition wall between the first housing chamber and the second housing chamber. The partition wall has a hole-like connecting portion that connects the first housing chamber and the second housing chamber. The partition wall may have a passage that connects the first housing chamber and the second housing chamber in addition to the hole-like connecting portion.

[0062] The first housing chamber accommodates the magnet portion, the stator, and one axial end of the shaft integrated with the magnet portion. In other words, the first housing chamber accommodates the axial part of the motor rotor including the magnet portion and the stator. The first housing chamber can also be considered as a motor chamber that accommodates the part of the electric liquid pump of the present invention that functions as the electric motor.

[0063] The second housing accommodates another axial portion of the shaft, i.e., another axial portion of the motor rotor. Furthermore, the second housing accommodates a general body portion, which is part of the body. For convenience of accommodating the body, it is preferable that the second housing accommodates an open end on the opposite side from the first housing. Hereinafter, this opening will be referred to as a case opening, as necessary.

[0064] As described above, the first and second housing chambers are separated by a partition wall and communicate with each other through a hole-like connecting portion. Therefore, the portion of the motor rotor between the portion housed in the first housing chamber and the other axial portion housed in the second housing chamber can be said to be housed in the hole-like connecting portion. Specifically, this portion is the portion between one axial end and the other axial end of the shaft.

[0065] In the electric liquid pump of the present invention, the material of the motor case is not particularly limited, but it is preferable that the motor case is also made of resin.

[0066] The body has a centering body portion and a general body portion. The centering body portion is inserted into the hole-like connecting portion to center the body relative to the motor case, and the outer shape of the centering body portion approximately matches the shape of the hole-like connecting portion.

[0067] The material of the body is not particularly limited, but considering durability, it is preferable to use a thermosetting resin. The thermosetting resin that is the material of the body will be described in detail later.

[0068] The general body portion is a portion that is continuous with the centering body portion and is housed in the second housing chamber of the motor case.

[0069] A bearing portion is formed through the centering body portion and the general body portion. The bearing portion is simply a through-hole without a bearing or the like. However, an oil groove may be provided in the bearing portion to improve lubrication between the shaft and the bearing portion.

[0070] When the case comprises a motor case and a body, the bearing portion formed through the centering body portion and the general body portion accommodates the portion of the motor rotor shaft between one end and the other end, i.e., the portion that is not integrated with any of the magnet portion, stator, or inner rotor.

[0071] An inner rotor is integrally formed on the other axial end of the motor rotor shaft. The inner rotor may be disposed outside the body, but in order to make the electric liquid pump of the present invention compact and lightweight, it is preferable to dispose it inside the body.

[0072] That is, it is preferable that a rotor accommodating chamber for accommodating the inner rotor and the outer rotor is provided at the end of the general body opposite the centering body, and the rotor accommodating chamber is connected to the bearing due to the positional relationship of the shaft, inner rotor, and outer rotor.

[0073] When the general body portion has a rotor accommodating chamber for accommodating the inner rotor and the outer rotor, it is preferable that the inner rotor and the outer rotor are also accommodated in the motor case together with the general body portion.

[0074] The general body portion and the motor case are integrated with each other by inserting the centering body portion into the hole-like connecting portion and centering them, but they may also be integrated at other portions. For example, if the second housing chamber has a case opening, the general body portion may close the case opening, and the general body portion and the motor case may be centered around the periphery of the case opening.

[0075] Furthermore, the centering portion between the general body and the motor case may also be used as a mounting portion for mounting the electric liquid pump of the present invention to a mating member, such as an oil pan, for supplying liquid to the pump. In this case, the structure for integrating the body and motor case in the electric liquid pump of the present invention and the structure for mounting the electric liquid pump of the present invention to the mating member can be made simple and compact. This contributes to further reducing the size and weight of the electric liquid pump of the present invention.

[0076] When the case includes the motor case and body, the liquid drawn into the liquid pump circulates inside the motor case, specifically, through the first and second chambers and the hole-like connecting portion. By circulating the liquid inside the motor case, a metal bearing or other structure is not required as a bearing portion of the electric liquid pump.

[0077] When the electric liquid pump of the present invention is configured such that liquid circulates inside the motor case, the liquid circulating inside the motor case is also supplied between a through-hole-shaped bearing portion provided in the body and the shaft supported by the bearing portion, and can function as a lubricant.

[0078] Therefore, in the electric liquid pump of this aspect of the present invention, it is possible to eliminate the need for bearings and still rotate the shaft more smoothly. As a result, the electric liquid pump of this aspect of the present invention has the advantage of being able to achieve weight reduction while maintaining excellent pump performance.

[0079] The material of the body is not particularly limited, and similar to the inner rotor and outer rotor described above, materials such as metal and resin can be used. When resin is used as the material of the body, the resin is preferably a thermosetting resin. The material of the body may be the same as or different from the material of the inner and outer rotors.

[0080] The thermosetting resin that can be used as the material for the inner rotor, outer rotor, and body is not particularly limited, and may be selected appropriately taking into consideration the deterioration resistance and infiltration resistance to the liquid that is sucked in and discharged by the electric liquid pump of the present invention, the seizure resistance and sliding properties of the bearing parts, etc. For example, if the electric liquid pump of the present invention is an oil pump for a vehicle, it is preferable to use a phenolic resin as the thermosetting resin.

[0081] In the present invention, the term "made of thermosetting resin" includes not only those made of only thermosetting resin, but also those made of a mixture of thermosetting resin and various compounding agents.

[0082] The compounding agent referred to here means a material other than the thermosetting resin, and examples thereof include reinforcing fibers such as glass fiber and carbon fiber, various inorganic fillers typified by mineral powders such as talc and mica, and glass beads, as well as various additives such as antifoaming agents and pigments.

[0083] The amount of compounding agent relative to the thermosetting resin is not particularly limited, but is preferably, for example, 90% by mass or less, 70% by mass or less, or 50% by mass or less relative to 100% by mass of the thermosetting resin.

[0084] In the electric liquid pump of the present invention, the material of the motor case is not particularly limited, but is preferably a resin material, and a thermosetting resin may also be selected as the material of the motor case.

[0085] The electric liquid pump of the present invention will be described below by way of a specific example.

[0086] Example 1 The electric fluid pump of the first embodiment is mounted on a vehicle and serves to suck up oil from an oil pan and supply it to a drive system such as a transmission, and the fluid in the electric fluid pump is oil.

[0087] Fig. 1 is an explanatory diagram that schematically illustrates the appearance of the electric liquid pump of Example 1. Fig. 2 is an explanatory diagram that schematically illustrates the electric liquid pump of Example 1 cut at position XX in Fig. 1. Fig. 3 is an explanatory diagram that schematically illustrates the electric liquid pump of Example 1 cut at position YY in Fig. 1. Figs. 4 to 6 are explanatory diagrams that schematically illustrate other examples of the motor rotor in the electric liquid pump.

[0088] Hereinafter, in the first embodiment, the terms "upper", "lower", "left", "right", "front" and "rear" refer to the respective directions shown in the drawings. The upper and lower directions correspond to the axial direction of the motor rotor.

[0089] As shown in FIGS. 1 to 3, the electric liquid pump 1 of the first embodiment includes an electric motor 2, a liquid pump 3, a motor case 4, and a body 5.

[0090] As shown in FIGS. 2 and 3, the electric motor 2 has a motor rotor 20 and a stator 25.

[0091] The motor rotor 20 has a shaft 21 and a magnet portion 23, and its axial cross section is substantially T-shaped. The shaft 21 is a long member made of SUS440C and includes a generally cylindrical shaft portion 21g and a generally disk-shaped sleeve 21s that is arranged coaxially with the general shaft portion 21g and is integrated with one end of the general shaft portion 21g. The sleeve 21s has a larger diameter than the general shaft portion 21g.

[0092] The magnet portion 23 is a bonded magnet containing SmFeN-based magnetic powder and a binder made of PA, and is integrated with the outer peripheral surface of the sleeve 21s, extending radially outward beyond the sleeve 21s.

[0093] The stator 25 is disposed radially outward of the magnet portion 23. The control board 7 is connected to the stator 25 via lead wires (not shown). 3, a lead wire 70 is further connected to the control board 7 and directed toward the outside of the electric liquid pump 1. The end of the lead wire 70 forms a connection terminal portion 71 for supplying power to the electric motor 2 of the first embodiment and for inputting and outputting signals.

[0094] The liquid pump 3 has an inner rotor 30 and an outer rotor 35. The inner rotor 30 and the outer rotor 35 are made of phenolic resin.

[0095] The inner rotor 30 has external teeth 31 and is integrated with the other axial end of the shaft 21, i.e., the lower end in Figures 2 and 3. Because the inner rotor 30 is integrated with the shaft 21 of the motor rotor 20, when the motor rotor 20 rotates due to the action of the stator 25 and the magnet portion 23, the inner rotor 30 rotates together with the motor rotor 20.

[0096] The outer rotor 35 has internal teeth 36 that mesh with the external teeth 31 of the inner rotor 30 , and is disposed outside the inner rotor 30 so as to surround the inner rotor 30 . A clearance volume 38 is formed between the inner rotor 30 and the outer rotor 35 to provide a pump function.

[0097] The motor case 4 is made of polyphenylene sulfide resin containing reinforcing fibers, is box-shaped, and has a case opening 40 that opens downward. A first housing chamber 41 and a second housing chamber 42 are provided inside the motor case 4. Inside the motor case 4, the first housing chamber 41 is located at the top and the second housing chamber 42 is located at the bottom, and a partition wall 45 is provided between the first housing chamber 41 and the second housing chamber 42.

[0098] The partition wall 45 is provided with a through-hole-like communicating portion 46 that passes through the partition wall 45 in the thickness direction, i.e., the vertical direction. In the electric liquid pump 1 of the first embodiment, the hole diameter of the communicating portion 46 is approximately the same as the inner diameter of the first storage chamber 41.

[0099] The first housing chamber 41 of the motor case 4 houses an upper portion of the motor rotor 20 including the magnet portion 23, and the stator 25. The stator 25 is disposed radially outward of the magnet portion 23 so as to surround the magnet portion 23.

[0100] The inner portion of the stator 25, i.e., the portion of the stator 25 on the motor rotor 20 side, is exposed to the first housing chamber 41. The outer portion of the stator 25 is outside the first housing chamber 41 and is embedded in the wall portion of the motor case 4.

[0101] In the electric liquid pump 1 of the first embodiment, the portion of the motor case 4 above the first housing chamber 41 is divided into an upper and lower section, with a board chamber 48 formed between them.

[0102] The board chamber 48 is liquid-tightly isolated from the first housing chamber 41 and the second housing chamber 42, and a control board 7 for the stator 25 is disposed in the board chamber 48. The control board 7 is electrically connected to the stator 25 by lead wires extending from the first housing chamber 41 to the board chamber 48. For this reason, a communication path (not shown) through which the lead wires pass is formed in the portion of the motor case 4 between the first housing chamber 41 and the board chamber 48. However, the gap between the communication path and the lead wires is liquid-tightly sealed at the boundary between the first housing chamber 41 and the board chamber 48. Therefore, the board chamber 48 in the electric liquid pump 1 of the first embodiment is liquid-tightly isolated from the first housing chamber 41 and the second housing chamber 42.

[0103] The hole-like communicating portion 46 and the second accommodating chamber 42 are continuous, and the portion of the motor rotor 20 other than the portion accommodated in the first accommodating chamber 41 is accommodated in the hole-like communicating portion 46 or the second accommodating chamber 42.

[0104] The body 5 is made of phenolic resin. A centering body portion 51, which is a part of the body 5, is inserted into the hole-like connecting portion 46. The outer shape of the centering body portion 51 is roughly the same as the hole shape of the hole-like connecting portion 46, so that the centering body portion 51 is fitted into the hole-like connecting portion 46 and is centered, i.e., positioned, with respect to the partition wall 45 and ultimately the motor case 4.

[0105] The upper portion of the general body portion 52, which is continuous with the centering body portion 51, is housed in the second housing chamber 42, which is continuous with the hole-like connecting portion 46. The outer shape of the upper portion of the general body portion 52 is slightly smaller than the inner shape of the second housing chamber 42, and a small space is formed in the outer portion of the general body portion 52 in the second housing chamber 42. This space functions as an oil circulation space.

[0106] 3, a plurality of recesses 53 are formed inside the general body portion 52. The interior of the recesses 53 communicates with the clearance volume 38 formed between the inner rotor 30 and the outer rotor 35.

[0107] A bearing portion 55 is formed to penetrate the centering body portion 51 and the general body portion 52. The bearing portion 55 is a through-hole extending in the vertical direction. A central portion of the shaft 21 of the motor rotor 20 is supported by the bearing portion 55. More specifically, the axial central portion of the shaft 21 of the motor rotor 20 is inserted into the through-hole-shaped bearing portion 55 provided in the body 5, and as a result, the bearing portion 55 supports the entire shaft 21, the magnet portion 23 integrated with one axial end of the shaft 21, and the inner rotor 30 integrated with the other axial end of the shaft 21.

[0108] The inner rotor 30 is integrated with the lower end of the shaft 21 of the motor rotor 20. The inner rotor 30 is housed together with the outer rotor 35 in a rotor housing chamber 56 provided at the end of the general body portion 52 opposite the centering body portion 51. The rotor accommodating chamber 56 is larger than the bearing portion 55, is located below the bearing portion 55, and is connected to the bearing portion 55. The bottom of the rotor accommodating chamber 56 is open. Furthermore, there is a recess 53 above the rotor accommodating chamber 56, and the interior of the recess 53 is connected to the rotor accommodating chamber 56. As described above, the inner rotor 30 and the outer rotor 35 are housed in the rotor accommodating chamber 56, and therefore it can be said that the interior of the recess 53 is also connected to the clearance volume 38 formed between the inner rotor 30 and the outer rotor 35 via the rotor accommodating chamber 56.

[0109] The lower end of the general body portion 52 is larger than the second housing chamber 42 , expands in a radial direction perpendicular to the up-down direction, and is exposed to the lower side of the motor case 4 through the case opening 40 . The lower end of the motor case 4, in other words, the peripheral edge of the case opening 40, also expands in a radial direction perpendicular to the up-down direction.

[0110] 2, through holes are formed at opposing positions in the lower end of the general body portion 52 and the periphery of the case opening 40. A fastener (not shown) is inserted into the through hole, and the lower end of the general body portion 52 is fixed to the periphery of the case opening 40 by the fastener. The lower end of the general body portion 52 can be said to close the case opening 40.

[0111] In the electric liquid pump 1 of the first embodiment, the shaft 21 of the motor rotor 20 is made up of a general shaft portion 21g and a sleeve 21s, and the general shaft portion 21g and the sleeve 21s are integrally molded from the same material, SUS440C. Therefore, the shaft 21 can be easily manufactured without any complicated processes, thereby reducing the manufacturing costs of the electric liquid pump 1 of the first embodiment.

[0112] In addition, the electric liquid pump 1 of Example 1 uses a bonded magnet containing SmFeN-based magnetic powder and a binder made of PA as the magnet portion, so the motor rotor 20 in the electric liquid pump 1 of Example 1 is lightweight and has a relatively small rotational torque.

[0113] Furthermore, in the electric fluid pump 1 of the first embodiment, liquid circulates inside the motor case 4. The liquid is also supplied between the bearing portion 55 of the body 5 and the shaft 21 supported by the bearing portion 55, and functions as a lubricant.

[0114] Therefore, the electric liquid pump 1 of the first embodiment does not require a bearing to support the shaft 21. Therefore, the electric liquid pump 1 of the first embodiment is small and lightweight.

[0115] Furthermore, in the electric liquid pump 1 of the first embodiment, the inner rotor 30, the outer rotor 35 and the body 5 are made of phenolic resin, which is a type of thermosetting resin, which also contributes to the light weight of the electric liquid pump 1 of the first embodiment.

[0116] Furthermore, thermosetting resin is less expensive and more moldable than sintered metal, so using thermosetting resin as the material for inner rotor 30, outer rotor 35, and body 5 reduces the manufacturing costs of inner rotor 30, outer rotor 35, and body 5. This further reduces the manufacturing costs of electric liquid pump 1 of the first embodiment.

[0117] As a result of the cooperation described above, the electric liquid pump 1 of the first embodiment can be manufactured at reduced cost and made lighter in weight.

[0118] In the electric liquid pump 1 of the first embodiment, the sleeve 21s of the motor rotor 20 is substantially disk-shaped, and in a projection view of the shaft 21 projected in the axial direction, the sleeve 21s is substantially circular. However, the motor rotor 20 in the electric liquid pump 1 of the present invention is not limited to this, and may take various shapes.

[0119] For example, the motor rotor 20 may have a sleeve 21s in the shape of a substantially regular polygonal plate, as shown in Fig. 4. The sleeve 21s of the motor rotor 20 shown in Fig. 4 has a substantially regular hexagonal shape in a projection view of the shaft 21 projected in the axial direction.

[0120] 5, the motor rotor 20 may have a plurality of grooves 21d in the sleeve 21s, which serve as flow paths for liquid. The grooves 21d are formed on one axial end surface of the sleeve 21s and open to the one axial end side. Each groove 21d extends radially from the inner side to the outer side in the radial direction of the sleeve 21s.

[0121] The electric liquid pump 1 has grooves 21d in the sleeve 21s, which allows the liquid that reaches the sleeve 21s to flow from the inside to the outside in the radial direction of the sleeve 21s as the motor rotor rotates. This allows the electric liquid pump 1 of this embodiment to quickly circulate the liquid inside the motor case 4.

[0122] Further, for example, the motor rotor 20 may have chamfered corners of the sleeve 21s as shown in Fig. 6. Chamfering the corners of the sleeve 21s has the advantage of being able to prevent cracks and the like in the sleeve 21s.

[0123] Although the present invention has been described above, the present invention is not limited to the above-described embodiments, etc., and it is possible to implement the present invention by appropriately extracting and combining elements described in the embodiments, etc., and to make various modifications within the scope that does not deviate from the spirit of the present invention. Furthermore, the specification of the present invention discloses not only the citation relationships of the claims at the time of filing but also the technical idea of ​​appropriately combining the matters described in the claims. [Explanation of symbols]

[0124] 1: Electric liquid pump 2: Electric motor 20: Motor rotor 21: Shaft 21d:Groove 21g: Standard shaft 21s:Sleeve 23: Magnet section 25: Stator 3: Liquid pump 30: Inner rotor 31: Outer teeth 35: Outer Rotor 36: Inner teeth 38: Clearance volume 4: Motor case 41: First Containment Cell 42: Second Containment Cell 45: Compartment wall 46: Hole-like connecting part 48: Substrate room 5: Body 51: Centering body part 52: General body part 55: Bearing part 7: Control board

Claims

1. an electric motor including a motor rotor having a shaft and a magnet portion integrated with one axial end of the shaft, and a stator disposed radially outside or inside the magnet portion to rotate the motor rotor; a liquid pump including: an inner rotor having external teeth and integral with the other axial end of the shaft; and an outer rotor having internal teeth that mesh with the external teeth and forming a clearance volume between the inner rotor and the outer rotor, into which liquid is sucked from a suction passage and into which liquid is discharged toward a discharge passage; a motor case having a box shape and including inside a first accommodating chamber that accommodates the stator and a portion of the motor rotor in the axial direction including the magnet portion, a second accommodating chamber that communicates with the first accommodating chamber and accommodates another portion of the motor rotor in the axial direction, and a partition wall that has a hole-like communicating portion that communicates the first accommodating chamber and the second accommodating chamber and is provided between the first accommodating chamber and the second accommodating chamber, and in which a liquid circulates between the first accommodating chamber, the second accommodating chamber, and the hole-like communicating portion; a body including a centering body portion inserted into the hole-like connecting portion and centered therein, a general body portion continuous with the centering body portion and accommodated in the second accommodation chamber, and a bearing portion formed through the centering body portion and the general body portion and supporting a part of the axial direction of the shaft at a position between the magnet portion and the inner rotor, the shaft is formed by integrally molding a large-diameter sleeve, which is the one end in the axial direction, and a general shaft portion, which is the remaining portion in the axial direction and has a smaller diameter than the sleeve, from the same material; The magnetic portion is made of a bonded magnet and is integrated into the sleeve.

2. an electric motor including a motor rotor having a shaft and a magnet portion integrated with one axial end of the shaft, and a stator disposed radially outside the magnet portion to rotate the motor rotor; a liquid pump including: an inner rotor having external teeth and integral with the other axial end of the shaft; and an outer rotor having internal teeth that mesh with the external teeth and forming a clearance volume between the inner rotor and the outer rotor, into which liquid is sucked from a suction passage and into which liquid is discharged toward a discharge passage; a box-shaped case that houses the liquid pump and the shaft; the shaft is formed by integrally molding a large-diameter sleeve, which is the one end in the axial direction, and a general shaft portion, which is the remaining portion in the axial direction and has a smaller diameter than the sleeve, from the same material; The magnetic portion is made of a bonded magnet and is integrated into the sleeve.

3. 3. An electric liquid pump according to claim 1 or claim 2, wherein the shaft is made of stainless steel.

4. 3. The electric liquid pump according to claim 1, wherein the bonded magnet contains SmFeN as a magnetic powder and polyamide or polyphenylene sulfide as a binder.

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