JP6550698B2 - Electric pump - Google Patents

Description

  The present invention relates to an electric pump including a rotor rotatably supported on a shaft member and an impeller fixed to one end of the rotor.

  2. Description of the Related Art Conventionally, an electric pump including a shaft member fixed to a casing and a rotor inserted outside the shaft member is known (see, for example, Patent Document 1). Further, a through passage is formed between the shaft member and the rotor along the axial direction. In order to release the fluid pressure inside the casing to the side of the impeller, a balance hole which penetrates one end of the rotor and communicates with the side of the blade member of the impeller is formed in the radially outward direction from the through passage.

  A part of the fluid that flows due to the rotation of the impeller is returned to the impeller side through the through passage and the balance hole while circulating through the casing to cool the electronic components and the like. At this time, the fluid passing through the through passage functions as a lubricant between the shaft member and the rotor.

JP 2006-296125 A

  However, in the conventional electric pump, since a through passage is formed between the shaft member and the rotor, this through passage is limited to a small size that does not cause the shaft to shake. For this reason, there is a possibility that the foreign matter mixed in the fluid closes the through passage and bites between the shaft member and the rotor, thereby inhibiting the rotation of the rotor.

  In addition, since the balance hole is in communication with the side of the blade member of the impeller, there is a possibility that the fluid may flow back to the inside of the casing under the large fluid pressure caused by the rotation of the impeller. As a result, the foreign matter mixed in the fluid is not discharged, and there is a problem that it stays in the casing.

  Accordingly, an object of the present invention is to rationally configure an electric pump that can smoothly discharge foreign matters mixed in a fluid without hindering the rotation of the rotor.

  The characteristic configuration of the electric pump according to the present invention includes a casing, a shaft member fixed to the casing, a cylindrical bearing portion inserted outside the shaft member, and a separate member from the bearing portion. A rotor integrally rotating with the bearing portion, and an impeller fixed to one end of the rotor, and discharging the fluid that flows out from the outer peripheral side of the impeller and circulates in the casing back to the impeller side A plurality of paths are formed between the bearing portion and the rotor in a state along the axial direction, and in the bearing portion, a plurality of projecting portions are provided in a dispersed manner along the circumferential direction on the outer peripheral surface; In order to restrict relative rotation between the bearing portion and the rotor, the inner circumferential surface is provided with a plurality of inner surface recessed portions in close contact with the plurality of projecting portions, and the plurality of discharge paths are along the circumferential direction. Distributed, and Lies in that said projection and said discharge passage are alternately arranged in the circumferential direction.

  According to this structure, the rotor comprised by a bearing part and this bearing part and another member rotates integrally around the fixed shaft member. That is, if a material having high wear resistance is selected only for the bearing portion, it is reasonable that a through passage for lubrication need not be provided between the shaft member and the rotor as in the prior art. In addition, the rotation of the rotor is not hindered by the inclusion of foreign matter between the shaft member and the bearing portion.

  Further, in the present configuration, the discharge path is provided between the integrally rotating bearing portion and the rotor, and compared with the case where the discharge path is provided between the non-rotating shaft member and the rotor as in the conventional case, As it is not affected, it is possible to secure a large cross-sectional area of the discharge passage. That is, even when a large foreign matter is mixed in the fluid, the discharge path is not blocked. Therefore, the foreign matter mixed in the fluid is returned to the impeller side without staying in the casing and discharged to the outside.

  As described above, the electric pump capable of smoothly discharging the foreign matter mixed in the fluid can be rationally configured without inhibiting the rotation of the rotor.

Other features configurations, prior Symbol impeller has a plurality of blade members in the circumferential direction, the one end of the rotor to the center side of the shaft member than the blade member is provided in a tubular shape, said one end and said bearing The outlet of the discharge passage is formed by the gap with the portion, and the axial position of the outlet of the discharge passage is closer to the inlet of the impeller in the axial direction than the axial position of the blade member. It is at a certain point.

  The fluid subjected to centrifugal force by the rotation of the impeller flows to the outer peripheral side of the impeller. That is, in the region where the impeller blade member is present, the flow velocity (fluid pressure) increases toward the outer peripheral side. As in this configuration, by providing the outlet of the discharge path on the center side of the shaft member with respect to the blade members of the impeller, that is, on the inner peripheral side of the impeller having the lowest fluid pressure, It can be smoothly drained to the side.

State Other features configurations, prior SL rotor, the said bearing part is made of a resin material for insert molding, a part of the region along the axial direction of the discharge path is not in contact with the outer surface of the bearing portion And the inlet side of the discharge passage is formed by the rotor, and the outlet side of the discharge passage is formed between the outer surface of the bearing portion and the inner surface of the rotor.

If the rotor is formed by insert molding of the bearing portion as in this configuration, the integrity between the rotor and the bearing portion is enhanced. Further, by setting a partial region along the axial direction of the discharge path not to be in contact with the outer surface of the bearing portion, the entire circumference of the bearing portion is surrounded by the resin constituting the rotor. As a result, since the resin shrinkage pressure received by the bearing portion is dispersed along the circumferential direction, the cross-sectional shape of the inner surface of the bearing portion is easily held in a circular shape. Thus, the bearing portion and the rotor can be smoothly rotated relative to the shaft member.
Other features configurations, the distal end surface side of the impeller of the previous SL bearing unit, in that a plurality of tip grooves communicating with the outlet of the discharge channel is extended radially from the center of the front end surface is formed is there.

It is sectional drawing which shows the whole structure which concerns on this embodiment. It is a fragmentary sectional view concerning this embodiment. It is the figure which looked at FIG. 2 from the front side. It is the figure which looked at FIG. 2 from the back side. It is a side view which shows a bearing part. It is VI-VI sectional drawing of FIG. It is the figure which looked at the end of the rotor from the front side. It is a fragmentary sectional view concerning another embodiment. It is the figure which looked at FIG. 8 from the back side.

  Below, an embodiment of electric pump P concerning the present invention is described based on a drawing. In the present embodiment, an electric water pump (hereinafter simply referred to as “electric pump P”) for circulating cooling water (an example of fluid) for cooling the engine of a vehicle will be described as an example. However, the present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the invention. Hereinafter, the description will be made with reference to the longitudinal direction of the rotor 5 in FIG. 1, with the impeller 6 side being the front and the side opposite the impeller 6 being the rear.

  FIG. 1 shows the overall configuration of an electric pump P according to the present embodiment. The electric pump P includes a resin casing 1, a metal shaft 3 (shaft member) fixed to the casing 1, a cylindrical bush 4 (bearing portion) inserted outside the shaft 3, and the bush 4 And a rotor 5 integrally rotating with the bush 4 and an impeller 6 fixed to a flange-like end 51 of the rotor 5.

  The bush 4 is composed of, for example, a carbon fiber / resin composite material or a carbon bearing such as carbon as a material having high wear resistance and high heat resistance that slides directly with the shaft 3. The rotor 5 is made of, for example, PPS (polyphenylene sulfide) as a resin material for insert-molding the bush 4. The bush 4 is not particularly limited as long as it is a material having high wear resistance and heat resistance. For example, the bush 4 may be made of metal such as resin or aluminum.

  Current control to the coil wound around the stator 8 is executed by an ECU (engine control unit) of a vehicle not shown, so that the magnet 54 of the rotor 5 receives an alternating magnetic field, and the bush 4 and the rotor 5 are integrated. Rotate.

  When the bush 4 and the rotor 5 integrally rotate, the impeller 6 fixed to one end 51 of the rotor 5 also rotates. As shown in FIGS. 1 to 3, the impeller 6 has a plurality of blade members 63 curved inside the shroud 64 and is covered with an impeller cover 2 made of resin. These blade members 63 are, for example, vibration welded to one end 51 of the rotor 5.

  Further, as shown in FIG. 1, between the impeller cover 2 and the bush 4 along the axial direction L, the shaft 3 and the bush 4 are fitted on the outer surface of the tip portion of the shaft 3 in a state in which the shaft 3 and the bush 4 are not relatively rotatable. A matching washer 7 is arranged. The washer 7 functions as a retainer for the bush 4.

  The rotation of the impeller 6 together with the integral rotation of the bush 4 and the rotor 5 causes the cooling water to flow from the suction port 61 to the outer peripheral side of the impeller 6 in a spiral manner. At this time, as shown in FIG. 1, most of the cooling water is sent out from the discharge port 62, and a part of the cooling water flows out from the outer peripheral side of the impeller 6 and circulates inside the casing 1. A part of the cooling water circulates inside the casing 1 to cool the rotor 5, the stator 8 and the like.

  On the other hand, foreign matter such as rust of metal parts or metal powder is mixed in the cooling water in the circulation path, and the foreign matter may clog and stay in a narrow passage formed inside the casing 1. In particular, since it is necessary to prevent the support function from being damaged around the axis of the shaft 3 that supports the rotor 5, a large flow path of the cooling water can not be secured. As a result, the cooling water can not be returned from the inside of the casing 1 to the side of the impeller 6, and there is a possibility that the generation of the rotation failure and the cooling function due to the biting of the foreign matter may be impaired.

  Therefore, in the present embodiment, the discharge passage 52 for returning the cooling water flowing out from the outer peripheral side of the impeller 6 and circulating inside the casing 1 back to the impeller 6 side along the axial direction L is the bush 4 and the rotor 5 Formed between. In particular, in this embodiment, the discharge path 52 is formed on the rotor 5 side so as to be in contact with the outer surface of the bush 4. As a result, when the bush 4 is insert-molded, since the discharge path 52 can be formed by inserting the core pin, there is no need to cut the bush 4 and manufacturing efficiency is good. In addition, since the discharge path 52 is formed between the bush 4 and the rotor 5, the degree of freedom of the dimensional shape of the discharge path 52 is increased, so that the inconvenience that foreign matters mixed in the cooling water are clogged can be solved.

  Further, in the present embodiment, the outlet 52 b of the discharge path 52 is provided on the center side of the shaft 3 from the blade member 63 of the impeller 6. The outlet 52b is also used as a so-called balance hole for releasing the fluid pressure inside the casing 1 to the impeller 6 side.

  In general, the balance hole passes through one end 51 of the rotor 5 and communicates with a region where the blade member 63 exists. For this reason, there is a possibility that the cooling water flows backward into the casing 1 due to the fluid pressure due to the rotation of the impeller 6. As a result, the fluid pressure inside the casing 1 is not released, and the rotation function of the rotor 5 is reduced. Moreover, the cooling water cannot be circulated from the inside of the casing 1 to the impeller 6, and the cooling function may be impaired. However, as in the present embodiment, by providing the balance hole inside the blade member 63 that is less affected by the fluid pressure due to the rotation of the impeller 6, the cooling water flows out smoothly from the inside of the casing 1 to the impeller 6 side. Can be made.

  As shown in FIG. 5, the bush 4 is formed in a cylindrical shape, and a plurality of protruding portions 41 surrounded by the insert molding resin of the rotor 5 are arranged on the outer peripheral surface at equal intervals along the circumferential direction (in the present embodiment). 3 places). When the protrusion 41 and the inner surface concave portion 56 of the rotor 5 are in close contact with each other, the relative rotation between the bush 4 and the rotor 5 is restricted, and both rotate integrally.

  As shown in FIGS. 4 to 5, a plurality of positioning recesses 42 cut out in the radial direction are formed on the rear end surface of the bush 4 opposite to the impeller 6. The positioning recesses 42 are arranged at equal intervals between the three protruding portions 41 along the circumferential direction of the bush 4 when the bush 4 is viewed from the rear side. That is, the protrusions 41 and the positioning recesses 42 are alternately arranged along the circumferential direction of the bush 4.

  When the bush 4 is insert-molded to form the rotor 5, a core pin is inserted along the longitudinal direction in which the positioning recess 42 is located. That is, the positioning recess 42 functions as a positioning guide for the discharge path 52 formed between the bush 4 and the rotor 5. Further, by bringing the insert molding die into contact with the positioning recess 42, the position of the bush 4 can be fixed.

  As shown in FIG. 3, in the tip end surface of the bush 4 on the side of the impeller 6, a plurality of tip grooves 43 are formed so as to extend radially from the center. The tip groove 43 serves as a passage for guiding the carbon powder generated by the friction between the shaft 3 and the bush 4 in the radially outward direction. The tip groove 43 communicates with the outlet 52b of the discharge passage 52, and as shown in FIG. 5, when the bush 4 is viewed from the front side, it is disposed at the same position in the circumferential direction as the three protruding portions 41. ing.

  The number and dimensions of the protrusion 41, the positioning recess 42 and the tip groove 43 are not particularly limited, and one or more locations along the circumferential direction of the bush 4 may be sufficient. However, when the bush 4 is viewed from the rear side, the protrusion 41 and the positioning recess 42 are arranged so as not to overlap.

  As shown in FIGS. 1 to 2, a magnet 54 is insert-molded inside the rotor 5 on the side opposite to the one end 51. As shown in FIG. 6, the magnet 54 is composed of a hexapole multipole magnet, and in a cross sectional view, the inner surface is formed in a hexagonal annular shape. In addition, the magnet 54 is not limited to six poles, You may comprise by the even number pole of two or more poles.

  At the hexagonal apex on the inner surface of the magnet 54, the protrusions 41 and the discharge passages 52 of the bush 4 are alternately arranged. That is, by disposing the projecting portion 41 in a portion where a large thickness of the resin constituting the rotor 5 is secured, the projecting amount of the projecting portion 41 can be configured large. For this reason, the dimensional shape of the protrusion 41 can be appropriately set in consideration of the rigidity of the bush 4 and the rotor 5. Furthermore, by disposing the discharge passage 52 in a portion where a large thickness of the resin constituting the rotor 5 is ensured, a large cross-sectional area of the discharge passage 52 can be ensured. Therefore, even when a large foreign matter is mixed in the cooling water, the discharge path 52 is not easily blocked. Therefore, the foreign matter mixed in the cooling water is smoothly discharged to the impeller 6 side without staying in the casing 1.

  As shown in FIG. 7, the number of rectangular insertion recesses 53 into which the rear end portion 63 a of the blade member 63 is inserted is equal to the number of the blade members 63 (7 places in this embodiment). Only forming. In a part of the plurality of insertion recesses 53, convex portions 53a that are spaced apart in the longitudinal direction of the insertion recess 53 are formed on both side surfaces. For this reason, when the blade member 63 is vibration welded to the one end face 51 a of the rotor 5, the axial center displacement of the blade member 63 is prevented. Further, when the impeller 6 rotates, the blade member 63 comes into contact with the convex portion 53a, thereby preventing relative movement in the rotational direction with respect to the one end surface 51a of the rotor 5.

  The insertion recess 53 in which the projection 53a is provided is not limited to a part, but may be provided in all, or when the insertion recess 53 is formed to the same size as the rear end of the blade member 63, the projection 53a Need not be provided.

[Another embodiment]
Only the configuration different from the above-described embodiment will be described with reference to FIGS. In addition, in order to make an understanding of drawing easy, it demonstrates using the same member name and code | symbol as embodiment mentioned above.

  In the present embodiment, a part of the discharge path 52 along the axial direction L passes through the interior of the rotor 5 without being in contact with the entire circumference of the bush 4. In other words, on the outer surface of the bush 4, in a partial region along the axial direction L, a resin surrounding portion 55 is formed, in which the resin constituting the rotor 5 surrounds the entire circumference. Further, in the present embodiment, the partial area is set to an area other than the vicinity of the inlet 52a and the outlet 52b in the discharge path 52, and the discharge path extends over the outer periphery of the bush 4 in the vicinity of the inlet 52a and the outlet 52b. 52 is in contact.

  Thereby, when the insert molding die is released, the resin shrinkage pressure received by the bush 4 is dispersed along the circumferential direction, so that the cross-sectional shape of the inner surface of the bush 4 is kept circular. For this reason, relative rotation with respect to the shaft 3 of the bush 4 is performed smoothly.

  Further, if the discharge path 52 is in contact with the outer periphery of the bush 4 in the vicinity of the outlet 52b, the impeller 6 can be arranged in the radially inward direction, so that the electric pump P can be made compact. Further, since a large cross-sectional area of the discharge path 52 can be ensured, the cooling water can be smoothly discharged to the impeller 6 side.

  The resin surrounding portion 55 in the present embodiment is formed by providing a step portion 55 a which is retracted inward in the circumferential direction at the tip end portion of the bush 4. However, this is only an example, and the resin surrounding portion 55 may be provided on the flush outer surface of the bush 4 without retracting the outer surface of the bush 4. Even in this case, it is possible to secure a large cross-sectional area of the discharge passage 52 as compared with the case where the discharge passage 52 is provided between the shaft 3 and the bush 4 as in the prior art.

Other Embodiments
(1) In the embodiment described above, the discharge path 52 is formed on the side of the rotor 5 between the bush 4 and the rotor 5, but it may be formed on the side of the bush 4 between the bush 4 and the rotor 5 good. Further, the discharge path 52 may be formed in a state straddling the bush 4 and the rotor 5.
(2) In the embodiment described above, a part of the discharge passage 52 along the axial direction L is not in contact with the entire circumference of the bush 4, but the entire region along the axial direction L May be in contact with the entire circumference of the bush 4. In addition, a part of the discharge path 52 along the axial direction L is not limited to a region excluding the vicinity of the inlet 52a and the outlet 52b, and may be set to a region excluding the vicinity of the inlet 52a or the outlet 52b.
(3) The method of integrating the bush 4 and the rotor 5 which are formed by separate members is not limited to insert molding, and for example, the rotor 5 may be pressed into the bush 4 or the like.
(4) The method of fixing the impeller 6 to the one end 51 of the rotor 5 is not limited to vibration welding, and various modifications such as heat welding and integral molding are possible.
(5) The electric pump P is not limited to a pump that circulates the engine coolant, and may circulate engine oil or may be used for applications other than vehicles. Moreover, the drive system of the electric pump P is not limited to the brushless motor that generates an alternating magnetic field, and a motor with a brush may be used.

  The present invention is applicable to an electric pump for circulating various fluids.

1 casing 3 shaft (shaft member)
4 Bushing (bearing)
5 rotor 6 impeller 51 one end 52 discharge path 52b outlet 63 blade member L axial direction P electric pump

Claims (4)

With the casing,
A shaft member fixed to the casing;
A cylindrical bearing portion inserted to the outside of the shaft member;
A rotor which is a separate member from the bearing and rotates integrally with the bearing;
And an impeller fixed to one end of the rotor.
A plurality of discharge paths returning from the outer peripheral side of the impeller and circulating to the inside of the casing to the impeller side are formed between the bearing portion and the rotor in a state along the axial direction,
In the bearing portion, a plurality of projecting portions are dispersedly provided along the circumferential direction on the outer peripheral surface, and in the rotor, in order to restrict relative rotation between the bearing portion and the rotor, in the inner peripheral surface A plurality of inner surface recesses in intimate contact with the plurality of projections;
The plurality of discharge paths are provided in a distributed manner along the circumferential direction, and the projecting portions and the discharge paths are alternately arranged in the circumferential direction. Before Symbol impeller has a plurality of blade members in the circumferential direction,
One end of the rotor is cylindrically provided on the center side of the shaft member with respect to the blade member, and a gap between the one end and the bearing portion forms an outlet of the discharge path.
2. The electric pump according to claim 1, wherein the axial position of the outlet of the discharge passage is closer to the inlet of the impeller in the axial direction than the axial position of the blade member. Before SL rotor, the bearing portion formed of a resin material for molding the insert,
A part of the discharge path along the axial direction passes through the rotor without contacting the outer surface of the bearing portion, and
The electric pump according to claim 1 , wherein an inlet side of the discharge passage is formed by the rotor, and an outlet side of the discharge passage is formed between an outer surface of the bearing portion and an inner surface of the rotor. The distal end surface side of the impeller of the previous SL bearing unit, any one of claims 1 to 3 in which a plurality of tip grooves communicating with the outlet of the discharge channel is extended radially from the center of the front end surface is formed The electric pump according to one item .

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