Electric liquid pump

Abstract

To provide a technique capable of reducing the size and weight of an 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, and a second housing chamber 42 housing another axial part of the motor rotor 20; and a body 5 having a bearing part supporting one axial part of the shaft 21. The motor case 4 and the body 5 are made of resin. A connection body part 54 of the body 5 and a connection case part 44 are enlarged in a radial direction of the shaft 21, and face the connection body part 54 on a centered body part 51 side. Through hole-like mounting parts 54a, 44a are formed on the connection body part 54 and the connection case part 44 at positions opposed to each other.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Known electric liquid pumps for transporting liquids such as oil include an electric motor as a driving source, and inner and outer rotors connected to the shaft of the electric motor to realize the pump function (see, for example, Patent Documents 1 to 4).

[0003] In this type of electric liquid pump, rotation of the electric motor shaft rotates the inner rotor, which is integrated with the shaft. This 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 Publication No. 2023-055912 [Patent Document 2] Japanese Patent Publication No. 2023-004065 [Patent Document 3] Japanese Patent Publication No. 2023-005537 [Patent Document 4] Japanese Patent Publication No. 2020-165375 Summary of the Invention [Problem to be solved by the invention]

[0005] Electric liquid pumps are generally provided with a mounting portion for mounting the electric liquid pump to a target member to which liquid is to be supplied from the electric liquid pump or to which liquid is to be supplied to the electric liquid pump.

[0006] For example, in the electric liquid pumps disclosed in Patent Documents 1 and 2, the attachment portion is disposed in the vicinity of the electric motor of the electric liquid pump. More specifically, the electric liquid pumps described in Patent Documents 1 and 2 have an electric motor and a liquid pump housed in a case, and a control board connected to the electric motor is located near the electric motor and outside the case. The control board is sandwiched between the case and a cover, and an attachment portion is formed on the cover.

[0007] In a typical electric liquid pump, various three-dimensional structures are provided near the electric motor, and therefore the portion of the electric liquid pump near the electric motor can be said to be a bulky portion. In the electric liquid pumps disclosed in Patent Documents 1 and 2, the cover is also provided with three-dimensional structures such as heat dissipation fins and a connector for connecting the control board to an external power source, which makes the cover bulky.

[0008] The electric liquid pumps disclosed in Patent Documents 1 and 2 have a problem in that the mounting portion is provided on a bulky cover, which significantly limits the degree of freedom in arranging the mounting portion. Furthermore, the cover is made of metal because it has heat dissipation fins, which makes it heavy. Adding the mounting portion to a cover that is already heavy also increases the weight of the electric liquid pump.

[0009] The electric liquid pump disclosed in Patent Document 3 has a mounting portion formed on its side. The mounting portion is made up of part of the case. In the electric liquid pump disclosed in Patent Document 3, mounting portions are located on both the electric motor side and the liquid pump side. Therefore, like the electric liquid pumps disclosed in Patent Document 1 and Patent Document 2, the electric liquid pump disclosed in Patent Document 3 also has the problem of limited flexibility in the arrangement of the mounting portions.

[0010] Furthermore, the mounting portion of the electric liquid pump introduced in Patent Document 3 consists of part of the case, and since the case is made of metal, providing an additional mounting portion on the metal case increases the mass of the electric liquid pump, making it difficult to reduce the weight of the electric liquid pump.

[0011] In the electric liquid pump disclosed in Patent Document 4, an attachment part is disposed on the liquid pump side of the case. However, the case of the electric liquid pump disclosed in Patent Document 4 is also made of metal and is heavy. Therefore, even with this technology, providing an attachment part on such a heavy metal case increases the overall mass of the electric liquid pump, and the problem of making it difficult to reduce the weight of the electric liquid pump is not solved.

[0012] Furthermore, the case of the electric liquid pump introduced in Patent Document 4 is divided into a motor housing, which is the part on the electric motor side, and a pump body, which is the part on the pump side. Patent Document 4 does not mention the attachment structure between the motor housing and the pump body. However, this electric liquid pump requires an attachment structure between the motor housing and the pump body in addition to the attachment part to the mating member described above, which creates the problem of further increasing the mass of the entire electric liquid pump.

[0013] Therefore, the various conventional electric liquid pumps described above have not been able to achieve sufficient size and weight reduction, and there is a demand for technology to further reduce the size and weight of electric liquid pumps.

[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 size and weight of an electric fluid pump. [Means for solving the problem]

[0015] The electric liquid pump of the present invention, which solves the above problems, 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 motor case and the body are made of resin, a connecting body portion of the body that is continuous with the general body portion and is located on the opposite side of the centering body portion extends in the radial direction of the shaft and is exposed on the opposite side of the centering body portion and on the outer side in the radial direction relative to the second accommodating chamber, a connection case portion, which is an end portion of the motor case on the connection body portion side, extends in the radial direction and faces the connection body portion on the centering body portion side; The electric liquid pump has through-hole-shaped mounting portions formed in the connection body portion and the connection case portion at positions facing each other. [Effects of the Invention]

[0016] The technology of the present invention makes it possible to reduce the size and weight of an electric liquid pump. [Brief explanation of the drawings]

[0017] [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. DETAILED DESCRIPTION OF THE INVENTION

[0018] The electric liquid pump of the present invention will be described below by way of a specific example.

[0019] The electric liquid pump of the present invention comprises a motor rotor, a stator, an inner rotor, an outer rotor, a motor case, and a body. The inner rotor and the outer rotor form the liquid pump, and the motor rotor and the shaft form an electric motor for driving the liquid pump.

[0020] The motor case and the body function as a housing for accommodating at least a portion of the liquid pump and the electric motor therein. The body also functions as a support mechanism for supporting the liquid pump and the electric motor.

[0021] As mentioned above, conventional electric liquid pumps have used metal cases.

[0022] In contrast, the electric liquid pump of the present invention uses a resin material for the motor case and body that make up the case. Because resin material is lighter than metal, the electric liquid pump of the present invention is significantly lighter overall.

[0023] In addition, in the electric liquid pump of the present invention, through-hole-shaped mounting portions are provided in the connecting body portion of the body and the connecting case portion of the motor case. The connecting body portion is the end of the body on the opposite side from the centering body portion (in other words, the liquid pump side), extends in the radial direction of the shaft, and is exposed on the opposite side from the centering body portion and radially outward from the second housing chamber. The connecting case portion is the end of the motor case on the connecting body portion side (in other words, the liquid pump side), extends in the radial direction like the connecting body portion, and faces the connecting body portion on the centering body portion side. In other words, the connecting body portion and the connecting case portion face each other radially outward from the second housing chamber and on the outside of the liquid pump side. The connecting body portion and the connecting case portion are formed with through-hole-shaped mounting portions at positions facing each other.

[0024] In the electric liquid pump of the present invention, the mounting portion is provided on the liquid pump side as described above, which provides greater freedom in the arrangement of the mounting portion than when the mounting portion is provided on the electric motor side.

[0025] The mounting portion is provided at a position facing the connection body portion and the connection case portion, and is shaped like a through hole. Therefore, the mounting portion functions not only as a mounting portion for the electric liquid pump to the mating member, but also as a connecting portion between the motor case and the body. In other words, with the electric liquid pump of the present invention, instead of providing two corners for a mounting portion for the electric liquid pump to the mating member and a connecting portion between the motor case and the body, only one mounting portion is required.

[0026] Therefore, the electric liquid pump of the present invention can have a smaller external size, which makes the entire electric liquid pump even smaller and lighter.

[0027] Additionally, in the electric liquid pump of the present invention, liquid circulates inside the motor case. This eliminates the need for a liquid-tight seal between the electric motor side and the liquid pump side of the case, simplifying the sealing mechanism. This also allows the electric liquid pump of the present invention to be made smaller and lighter.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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. 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] The shaft may have a constant radial cross section, or may have a T-shaped cross section with a sleeve of a larger diameter at one end in the axial direction, i.e., the part integrated with the magnet part, compared to the other parts. If the shaft has a sleeve, the magnet part is integrated with the sleeve. Therefore, when a sleeve is provided on the shaft, it can effectively function as a back yoke as described above, and also has the advantage of being able to reduce the magnet part by the amount of the sleeve.

[0034] The magnet portion may be any permanent magnet that can generate a magnetic field. For example, a bonded magnet may be used as the magnet portion.

[0035] 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. By using a bonded magnet as the magnet portion, it is possible to reduce the mass of the magnet portion by the amount of the binder.

[0036] Incidentally, an electric liquid pump having a motor rotor with a large rotational torque requires a bearing portion including a metal bearing as a bearing for supporting the shaft of the electric motor. Bearings are mechanisms 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 relatively heavy component. For this reason, it is difficult to reduce the weight of an electric fluid pump that includes such a bearing in its bearing section.

[0037] The bearing portion of the electric liquid pump of the present invention is formed by penetrating the centering body portion and the general body portion of the resin body. The electric motor shaft is supported by the bearing portion. Furthermore, in the electric liquid pump of the present invention, the liquid drawn in and discharged by the liquid pump circulates within the motor case. Since the liquid is also supplied between the body and the shaft, it can function as a lubricant.

[0038] In the electric liquid pump of the present invention, by circulating liquid inside the motor case, it is possible to smoothly rotate the shaft even though a part of the body is made of resin, which is lighter than metal, instead of bearings. In other words, in the electric liquid pump of the present invention, the motor rotor rotates smoothly even without using metal bearings or the like as bearing parts to support the electric motor shaft. This also makes it possible to achieve a lightweight electric liquid pump of the present invention.

[0039] In addition, when a bonded magnet is used as the magnet portion of the motor rotor, the rotational torque of the motor rotor is further reduced, which has the advantage of allowing the shaft to rotate even more smoothly.

[0040] In the electric liquid pump of the present invention, the method for integrating the magnet portion and the shaft is not particularly limited. For example, they may be integrated during molding by insert molding or the like, or a pre-molded magnet portion may be fixed to the shaft using a method such as adhesive.

[0041] 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.

[0042] The liquid pump has an inner rotor and an outer rotor.

[0043] The inner rotor has external teeth and is integrated with the other axial end of the shaft, so that the inner rotor rotates together with the shaft.

[0044] 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.

[0045] 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.

[0046] The inner rotor and outer rotor for forming the clearance volume may have any shape that is generally used in liquid pumps.

[0047] 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.

[0048] The inner rotor and the outer rotor may have any general shape that can perform the above-mentioned pump function.

[0049] In the electric liquid pump of the present invention, the materials of the inner rotor and the outer rotor are not particularly limited, and they may be made of metal such as aluminum, or resin. At least one of the inner rotor and the outer rotor is preferably made of resin, and a thermosetting resin is particularly preferred. Hereinafter, the inner rotor or the outer rotor that is made of resin may be referred to as a resin rotor, as necessary.

[0050] By using a resin rotor for at least one of the inner rotor and the outer rotor, it is possible to reduce the weight of the resin rotor, and therefore the weight of the electric liquid pump itself.

[0051] In particular, by using a thermosetting resin as the material of the resin rotor, the manufacturing cost can be reduced while maintaining the heat resistance of the resin rotor.

[0052] 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.

[0053] In the electric liquid pump of the present invention, the case for housing the electric motor and the liquid pump includes a motor case and a body. The motor case and the body are made of a resin material, which will be described in detail later.

[0054] The motor case is a box-shaped member that houses the motor rotor having a magnet portion, the stator, and the body.

[0055] 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.

[0056] The first housing chamber accommodates the magnet unit, the stator, and one axial end of the shaft integrated with the magnet unit. In other words, the first housing chamber accommodates a part of the axial direction of the motor rotor 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.

[0057] The second housing chamber accommodates another axial portion of the shaft, i.e., another axial portion of the motor rotor. Furthermore, the second housing chamber accommodates a general body portion, which is part of the body. For the convenience of accommodating the body, and because the connecting case portion of the motor case and the connecting body portion of the body are integrated by the attachment portion radially outward from the second housing chamber and on the outside of the liquid pump side, as described above, the end of the second housing chamber opposite the first housing chamber is open. Hereinafter, this opening will be referred to as the "case opening" as necessary.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] In the electric liquid pump of the present invention, 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 either the magnet portion or the inner rotor.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] In the electric liquid pump of the present invention, the body and the motor case are integrated by further centering the connecting body portion of the body and the connecting case portion of the motor case with the centering body portion inserted into the hole-like connecting portion. The connecting body portion extends radially and is exposed radially outward on the opposite side of the centering body portion from the second housing chamber. Therefore, when the body and the motor case are integrated, the general body portion can be said to close the case opening of the second housing chamber. Since the connection body and the connection case are located radially outward from the second housing chamber, the connection body and the connection case are located on the periphery of the case opening, and the general body and the motor case are also centered on the periphery of the case opening.

[0067] Furthermore, the mounting portions provided on the connection body portion and the connection case portion function as mounting portions for mounting the electric liquid pump of the present invention to a mating member, i.e., an oil pan for supplying liquid to the liquid pump, or a target for supplying liquid from the liquid pump, such as a transmission. This allows the electric liquid pump of the present invention to have a structure for integrating the body and motor case and a structure for mounting the electric liquid pump of the present invention to a mating member that is simple and compact. This allows the electric liquid pump of the present invention to be further reduced in size and weight.

[0068] The attachment portion of the connection case portion and the attachment portion of the connection body portion may have the same diameter or different diameters.

[0069] The suction and discharge passages of the electric liquid pump are located on the liquid pump side. Therefore, when the electric liquid pump is connected to a mating member, the liquid pump faces the mating member. Because the connection body is located closer to the liquid pump than the connection case, the electric liquid pump of the present invention can be said to face the connection body toward the mating member.

[0070] When considering ease of installation and cost, the preferred method for attaching the electric liquid pump to the mating member is to bolt the electric liquid pump to the mating member. To bolt the electric liquid pump to the mating member, bolts are inserted through the through-hole-shaped mounting portions of the connection case and the connection body. More specifically, the bolts are inserted from the mounting portions of the connection case toward the mounting portions of the connection body, with the tip of the bolt pointing toward the mating member.

[0071] When the bolt is fastened to a mating member, the head of the bolt presses against the periphery of the attachment part of the connection case, so in order to ensure the strength of the bolt fastening, it is preferable to reinforce the attachment part of the connection case.

[0072] Specifically, it is preferable that the hole diameter of the attachment portion of the connection case portion be larger than the hole diameter of the attachment portion of the connection body portion, and that a hard collar portion be embedded in the attachment portion of the connection case portion. The collar may be cylindrical, but preferably has a flange exposed on the surface facing the connection case and / or the surface opposite the connection case, and the flange may have a brim-like shape that extends radially from the attachment portion of the connection case.

[0073] As described above, in the electric liquid pump of the present invention, the motor case and the body are made of a resin material. The body, which includes a bearing that supports the shaft, must be highly durable. The body is also exposed to liquid. Therefore, a thermosetting resin is preferably selected as the material for the body, as it offers excellent resistance to deterioration and infiltration by the liquid drawn in and discharged by the electric liquid pump of the present invention, as well as excellent seizure resistance and sliding properties for the bearing. For example, if the electric liquid pump of the present invention is an oil pump for a vehicle, a phenolic resin is preferably used as the thermosetting resin.

[0074] The motor case is not subjected to the same load as the body. Therefore, a cheaper material with inferior properties compared to the body material can be selected for the motor case. For example, the motor case can be made of thermoplastic resin, and engineering plastics such as polyphenylene sulfide (PPS) are more suitable. This is because engineering plastics have superior properties compared to other thermoplastic resins. The specific gravity of PPS is greater than that of phenolic resin. However, the motor case does not require the same rigidity as the body. Therefore, the motor case can be thinner than the body, allowing the use of a material with a higher specific gravity for the motor case. Even though PPS has a higher specific gravity than phenolic resin, its specific gravity is still much lower than that of metal. For reference, the specific gravity of aluminum is 2.7, that of phenolic resin is approximately 1.24 to 1.32, and that of PPS is approximately 1.35.

[0075] In order to reduce the weight of the electric liquid pump of the present invention, it is preferable that the inner rotor and the outer rotor are also made of a thermosetting resin. The materials of the inner rotor and the outer rotor may be the same or different. Furthermore, the material of the inner rotor and outer rotor may be the same as or different from that of the body.

[0076] The thermosetting resin used as the material for the body and, if necessary, the material for the inner rotor and / or outer rotor is not particularly limited, but as mentioned above, a phenol resin is preferable.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] The electric liquid pump of the present invention will be described below by way of a specific example.

[0081] 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.

[0082] 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. 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.

[0083] 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.

[0084] As shown in FIGS. 2 and 3, the electric motor 2 has a motor rotor 20 and a stator 25.

[0085] The motor rotor 20 has a shaft 21 and a magnet portion 23, and its axial cross section is substantially T-shaped. Of these, the shaft 21 is a long member made of magnetic metal, and has a sleeve 21s at one end in the axial direction, the sleeve 21s having a larger diameter than the other portions.

[0086] The magnet portion 23 is a bonded magnet, which is integrated with the outer peripheral surface of the sleeve 21s and extends radially outward beyond the sleeve 21s.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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 49 is formed in the outer portion of the general body portion 52 in the second housing chamber 42. This space 49 functions as an oil circulation space.

[0100] 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.

[0101] 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 25.

[0102] 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.

[0103] The connecting body portion 54, which is the lower end portion of the body 5, is larger than the second accommodating chamber 42 and extends in the vertical direction, i.e., in the radial direction perpendicular to the axial direction, and is exposed below and radially outward from the motor case 4 through the case opening 40. The lower end of the motor case 4, in other words, the connection case portion 44, which is the end of the motor case 4 on the connection body portion 54 side, extends in the vertical direction, i.e., in the radial direction perpendicular to the axial direction. The connection case portion 44 can also be referred to as the peripheral portion of the case opening 40.

[0104] 2, the connection body portion 54 and the connection case portion 44 face each other. The connection body portion 54 and the connection case portion 44 have through-hole-shaped attachment portions (attachment portion 54a of the connection body portion 54 and attachment portion 44a of the connection case portion 44) formed at positions facing each other. The attachment portion 54a of the connection body portion 54 and the attachment portion 44a of the connection case portion 44 are connected to each other. The hole diameter of the attachment portion 44a of the connection case portion 44 is larger than the hole diameter of the attachment portion 54a of the connection body portion 54, and a hard collar portion 44c is embedded in the attachment portion 44a of the connection case portion 44.

[0105] A bolt (not shown) is inserted into the mounting portion 54a of the connection body portion 54 and the mounting portion 44a of the connection case portion 44, and the bolt is fastened to a nut (not shown) on the mating member (not shown). This attaches the motor case 4 and the body 5 to the mating member, and the motor case 4 and the body 5 are also attached to each other. At this time, the lower end of the general body portion 52 can be said to close the case opening 40.

[0106] 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, and the motor case is made of PPS, which is a type of thermoplastic resin, so that the electric liquid pump 1 of the first embodiment is lightweight.

[0107] Furthermore, in the electric liquid pump 1 of the first embodiment, the mounting portion 54a of the connection body portion 54 and the mounting portion 44a of the connection case portion 44 are provided at positions on the liquid pump 3 side of the electric liquid pump 1. This provides greater freedom in the arrangement of the mounting portions 54a and 44a than when the mounting portions 54a and 44a are provided on the electric motor 2 side.

[0108] Furthermore, the electric liquid pump 1 of the first embodiment is attached to a mating member (not shown) by the attachment portions 54a and 44a, and the motor case 4 and the body 5 are integrated together. This allows the electric liquid pump 1 of the first embodiment to be further reduced in size and weight.

[0109] Additionally, in the electric liquid pump 1 of the first embodiment, liquid circulates inside the motor case 4. Therefore, it is not necessary to liquid-tightly seal the first housing chamber 41, which is the space on the electric motor 2 side, and the second housing chamber 42, which is the space on the liquid pump 3 side, inside the motor case 4. Therefore, with the electric liquid pump 1 of the first embodiment, the sealing mechanism can be simplified, and the electric liquid pump 1 can be made even smaller and lighter.

[0110] Furthermore, the electric liquid pump 1 of the first embodiment does not require a bearing to support the shaft 21. This also makes the electric liquid pump 1 of the first embodiment small and lightweight.

[0111] Furthermore, in the electric liquid pump of Example 1, the body 5 not only houses the liquid pump 3, but also supports the liquid pump 3 and the electric motor 2. Because the body 5 thus performs many functions, the number of parts in the electric liquid pump 1 of Example 1 is reduced, which in turn reduces the number of steps required to manufacture the electric liquid pump 1 and, ultimately, reduces the manufacturing costs of the electric liquid pump 1.

[0112] Furthermore, sintered metal, which is generally used as the material for the case, inner rotor 30, and outer rotor 35, is expensive and requires special cutting processes for molding, making the metal case, inner rotor 30, and outer rotor 35 expensive, whereas resin materials are less expensive than sintered metals and have excellent moldability. Therefore, by using resin materials for the motor case 4, body 5, inner rotor 30, and outer rotor 35, the manufacturing costs of the motor case 4, body 5, inner rotor 30, and outer rotor 35 can be significantly reduced. This also has the advantage of significantly reducing the manufacturing costs of the electric liquid pump 1 of the first embodiment.

[0113] By combining the above, it is possible to reduce the size and weight of the electric liquid pump 1 of Example 1. In addition, the electric liquid pump 1 of Example 1 can be manufactured inexpensively.

[0114] 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]

[0115] 1: Electric liquid pump 2: Electric motor 20: Motor rotor 21: Shaft 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 44: Connection case part 44a: Mounting part of the connection case 44c: Color section 45: Compartment wall 46: Hole-like connecting part 48: Substrate room 49: Space 5: Body 51: Centering body part 52: General body part 54: Connection body part 54a: Mounting part of connecting body 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 motor case and the body are made of resin, a connecting body portion of the body that is continuous with the general body portion and is located on the opposite side of the centering body portion extends in a radial direction of the shaft and is exposed on the opposite side of the centering body portion and on the outer side in the radial direction with respect to the second accommodating chamber, a connection case portion, which is an end portion of the motor case on the connection body portion side, extends in the radial direction and faces the connection body portion on the centering body portion side; The electric liquid pump has through-hole-shaped mounting portions formed in the connection body portion and the connection case portion at positions facing each other.

2. 2. The electric fluid pump according to claim 1, wherein a space is formed around the outer periphery of the general body portion in the second housing chamber.

3. 3. The electric liquid pump according to claim 1, wherein the body is made of a thermosetting resin.

4. 4. The electric liquid pump of claim 3, wherein said motor case is made of a thermoplastic resin.

5. a hole diameter of the attachment portion of the connection case portion is larger than a hole diameter of the attachment portion of the connection body portion; 3. The electric liquid pump according to claim 1, wherein a hard collar is embedded in the attachment portion of the connection case portion.

6. 5. The electric liquid pump of claim 4, wherein the thermosetting resin comprises a phenolic resin.

7. 7. The electric liquid pump according to claim 6, wherein the thermosetting resin contains reinforcing fibers and / or inorganic fillers in an amount of 30% by mass to 90% by mass, both inclusive, when the total mass is taken as 100% by mass.

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