JP7126467B2 - Bearing structure in electric fluid pump - Google Patents

Description

The present invention comprises a casing having a suction port, a support shaft having at least one end held by a holding portion provided in the casing and arranged inside the suction port, and an inner hole through which the support shaft is inserted. an impeller and a rotor rotatably supported by the support shaft via the bearing means and fixed to the bearing means; a first restricting portion for restricting movement of the bearing means toward the suction port side so as to be in a fixed position within the casing at least when the impeller rotates; and a second restricting portion fixedly arranged in the casing to restrict the movement of the bearing means, and the axial movement between the first restricting portion and the second restricting portion of the bearing means immersed in the handled fluid is prevented. It relates to possible electric fluid pumps, and in particular to improved bearing structures.

Such an electric fluid pump is already known from US Pat.

JP 2015-183650 A

In the technique disclosed in Patent Document 1, an impeller and a rotor supported by a support shaft via a slide bearing are fixed to the slide bearing, and thrust plates are disposed facing both ends of the slide bearing. A suction means is provided between the thrust plate and the slide bearing for sucking the fluid between the slide bearing and the support shaft when the impeller rotates, and between the other thrust plate and the slide bearing, when the impeller rotates, the fluid is drawn from between the slide bearing and the support shaft. A discharge means is provided for discharging, so that when the impeller rotates, fluid is always circulating to lubricate between the slide bearing and the support shaft. For this reason, foreign matter mixed in the fluid, such as fine dust, rusted metal powder, abrasion powder of the sliding bearing, etc., is caught in the sliding surface of the sliding bearing, resulting in an increase in rotational resistance and abnormal wear. there is a possibility.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and is intended to prevent the fluid to be handled from flowing between the support shaft and the bearing means while the impeller is rotating, thereby preventing an increase in rotational resistance and abnormal wear. It is an object of the present invention to provide a bearing structure in an electric fluid pump which can contribute to improvement in durability of bearing means.

In order to achieve the above object, the present invention provides a casing having an inlet, a support shaft having at least one end held by a holding part provided in the casing and arranged inside the inlet, and bearing means having a cylindrical bearing cylinder portion having an inner hole through which a shaft is inserted and exerting a sliding bearing function; a fixed impeller and rotor; a first restricting portion that restricts movement of the bearing means toward the suction port side so as to be in a fixed position within the casing at least when the impeller rotates; a second restricting portion that is fixedly arranged within the casing to restrict movement to the side opposite to the suction port; In the electric fluid pump capable of axial movement between the parts, the fluid to be handled is provided on the inner surface of the inner hole of the bushing part between the support shaft and the bearing means over the axial ends of the bearing means. is formed on the first end face of the bearing means on the side of the first restricting portion, the lubrication groove of the first end face according to the pressure received by the impeller when the impeller rotates. 1. A concave portion which is closed by pressure contact with the regulating portion but is opened when the impeller stops is released in response to pressure contact of the first end face with the first regulating portion is released along the radial direction of the support shaft. The inner end portion is communicated with the lubrication groove and the outer end portion along the radial direction is formed to have a closed shape, and the second end surface of the bearing means on the second restricting portion side communicates with the lubrication groove. A first feature is that the discharge groove is formed so as to be able to discharge the handled fluid radially outward.

In addition to the configuration of the first characteristic, the present invention is characterized in that the bearing means includes the first restricting portion in the first bushing portion having the first inner hole in which the first lubricating groove is formed. A first slide bearing integrally provided with a first restricting portion-side flange portion opposed to and formed with the recess, and a second sliding bearing having the second inner hole formed with the second lubrication groove A second sliding bearing formed by integrally providing a second restricting portion-side flange portion in which the discharge groove is formed and which faces the second restricting portion to the bearing cylinder portion of the second sliding bearing. characterized by

In the present invention, in addition to the configuration of the first characteristic, the bearing means are provided on both axial end surfaces of the single bearing cylinder portion disposed between the first restricting portion and the second restricting portion. A third feature is that the recess and the discharge groove are respectively formed.

Further, in addition to any one of the configurations of the first to third characteristics, the present invention is characterized in that the axis of the support shaft is oriented vertically with one end side of the support shaft held by the holding portion as an upper position. A fourth feature is that it is arranged as follows.

According to the first feature of the present invention, when the impeller rotates, the first end surface of the bearing means on the side of the first restricting portion is pressed against the first restricting portion according to the pressure received by the impeller. As a result, the recess formed in the inner hole of the bearing means is closed, and the flow of the fluid to be handled to the lubricating groove formed in the inner hole of the bearing means is blocked. On the other hand, when the impeller stops, the pressure contact of the first end face to the first restricting portion is released, thereby opening the recess, allowing the fluid to flow from the recess through the lubricating groove to the discharge groove. That is, when the impeller is rotating, the handled fluid does not flow between the bearing means and the support shaft, and when the impeller is stopped, the handled fluid can flow between the bearing means and the support shaft. For this reason, the impeller rotation causes the fluid to be handled to flow, causing foreign matter to be stirred up, thereby preventing the suspended fluid from flowing between the bearing means and the support shaft. Only when the fluid is exchanged on the sliding surface of the bearing means is exchanged, and problems such as abnormal wear of the bearing means and increased rotational resistance due to the entry of foreign matter such as abrasion powder are avoided. It can contribute to improvement in durability of the bearing means. Further, when the first restricting portion cannot rotate, the first end surface is brought into sliding contact with the first restricting portion so that the thrust load from the bearing means side is received by the first restricting portion when the impeller rotates. However, it is possible to lubricate between the first end face and the first regulating portion with the handled fluid accumulated in the concave portion formed in the first end face. can be increased, and durability can be improved.

According to the second feature of the present invention, the first restricting portion-side flange portion of the first sliding bearing of the first and second sliding bearings constituting the bearing means faces the first restricting portion, Since the second regulating portion-side flange portion of the second sliding shaft faces the second regulating portion, the contact area between the first and second regulating portions and the bearing means is increased to keep the surface pressure low, The seed resistance between the sliding bearing of 1 and the first restricting portion can be reduced.

According to the third feature of the present invention, the number of parts can be reduced because the bearing means consists of a single bearing cylinder.

Further, according to the fourth feature of the present invention, one end of the support shaft held by the holding portion is positioned upward, and the axis of the support shaft is oriented vertically. The end face can be spaced apart from the first restricting portion.

1 is a partially cutaway perspective view of an electric fluid pump according to a first embodiment; FIG. It is the perspective view which looked at the support shaft, the 1st control part, and the 1st slide bearing from the upper direction. It is the perspective view seen from the downward direction of the 2nd slide bearing. FIG. 5 is a longitudinal sectional view of an electric fluid pump of a second embodiment;

Embodiments of the present invention will be described with reference to the accompanying drawings.

A first embodiment of the present invention will be described with reference to FIGS. 1 to 3. First, in FIG. a support shaft 8; an impeller 9 rotatably supported by the support shaft 8 and housed in the pump chamber 6; a rotor 10 housed in the pump chamber 6 so as to rotate together with the impeller 9; and a stator 11 arranged to surround the rotor 10 outside the casing 7 .

The casing 7 includes a suction cylinder portion 13b extending vertically so as to form a suction port 12 opening at the upper end of the central portion of the pump chamber 6, and a discharge port extending tangentially to the outer peripheral portion of the pump chamber 6. It is composed of a pump case 13 having a tubular portion 13c and a can-shaped case member 14 coupled to the pump case 13 so as to form the pump chamber 6 between the pump case 13 and the pump case 13 .

The pump case 13 includes a dish-shaped pump case main portion 13a that is open downward, the suction cylinder portion 13b that is connected to the center of the upper end of the pump case main portion 13a, and the pump case 13 that is connected to the outer periphery of the pump case 13. and a first flange portion 13d projecting radially outward from the lower end of the pump case main portion 13a. 13d is formed with a step so as to be lower than the outer side or the inner side along the radial direction of the pump case main portion 13a.

The case member 14 includes a bottomed cylindrical portion 14a having an inner diameter smaller than the inner diameter of the pump case main portion 13a and having an open top, and a bottomed cylindrical portion 14a projecting radially outward from the upper end portion of the bottomed cylindrical portion 14a. It is formed of synthetic resin integrally with a second flange portion 14b that abuts and fits into the first flange portion 13d from below.

An intermediate case member 15 and a cover member 16 sandwiching the intermediate case member 15 and the casing 7 are coupled to the casing 7 . The intermediate case member 15 includes a cylindrical case member main portion 15a coaxially surrounding the bottomed cylindrical portion 14a and a third flange portion 15b projecting radially outward from the upper portion of the case member main portion 15a. and a fourth flange portion 15c projecting radially outward from the lower portion of the case member main portion 15a, and the upper portion of the case member main portion 15a and the third flange portion 15b The third flange portion 15b is fitted to the second flange portion 14b such that the third flange portion 15b is brought into contact with the second flange portion 14b from below, and the first flange portion 13d and the third flange portion 15b are fitted. They are coupled to each other with the second flange portion 14b interposed therebetween.

The cover member 16 includes a cover member main portion 16a formed in a bottomed cylindrical shape with a closed lower end, and a lower end of the intermediate case member 15 projecting radially outward from the upper end of the cover member main portion 16a. A fifth flange portion 16b coupled from below to the fourth flange portion 15c of the portion is integrally provided, and an annular seal is provided between the fourth flange portion 15c and the fifth flange portion 16b. A member 17 is clamped.

The stator 11 is fixed to the outer surface of the bottomed cylindrical portion 14 a of the case member 14 , and the stator 11 is surrounded by the case member main portion 15 a of the intermediate case member 15 . A control circuit board 18 is accommodated and fixed in the cover member main portion 16 a of the cover member 16 .

At least one end of the support shaft 8, in this embodiment, the uppermost end of the support shaft 8 is provided in the pump case 13 of the casing 7 and arranged inside the suction port 12. It is held by the holding portion 20 .

The holding portion 20 is arranged in the center portion of the end portion of the suction cylinder portion 13b on the side of the pump chamber 6, and is opened downward so as to fit the one end portion of the support shaft 8 thereon. It has a fitting recess 21, and is integrally connected to the inner periphery of the pump chamber 6 side end of the suction tube portion 13b via a plurality of support arm portions 22 arranged at intervals in the circumferential direction. .

2, a flat notch surface 23 is formed in a portion of the outer periphery of the support shaft 8 near the one end, and the fitting recess 21 is formed in the cross section of the support shaft 8. It is formed to have a cross-sectional shape corresponding to the shape. That is, one end of the support shaft 8 is non-rotatably held by the holding portion 20 .

Further, the case member 14 integrally has a cylindrical support cylinder portion 14c extending upward from the bottom closed portion of the bottomed cylinder portion 14a, and the other end of the support shaft 8 is the support cylinder portion 14c. fitted within. Moreover, the support cylinder portion 14c is formed to have a socket length that can receive about 30% of the total length of the support shaft 8. As shown in FIG. As a result, the support cylinder portion 14c forms a part of the case member 14 and is integrally connected to the support cylinder portion 14c. The support shaft 8 is accurately positioned and held coaxially.

The rotor 10 is composed of a rotor hub 24 and bond magnets 25 fixed to the rotor hub 24 . The rotor hub 24 includes a cylindrical magnet support portion 24a that coaxially surrounds the support cylinder portion 14c, and a magnet support portion 24a that is smaller in diameter than the magnet support portion 24a and coaxially surrounds the support shaft 8. An extension cylinder portion 24b extending upward from the upper end portion of the magnet 24a is coaxially and integrally connected to the extension cylinder portion 24b. The impeller 9 is fixed to the upper portion of the portion 24b by snap fitting or the like.

The rotor 10 and the impeller 9 fixed to the extended cylindrical portion 24b of the rotor hub 24 are rotatably supported by the support shaft 8 via bearing means 27 that exhibits a sliding bearing function. The bearing means 27 is immersed in the fluid to be handled, such as cooling water, which is pumped by the impeller 9 so as to use the fluid to be handled as a lubricating fluid.

The bearing means 27 includes a washer 28 as a first restricting portion fixedly arranged in the casing 7 at least when the impeller 9 rotates, and the support cylinder as a second restricting portion fixedly arranged in the casing 7. The movement of the bearing means 27 toward the suction port 12 is restricted by the washer 28, and the movement of the bearing means 27 toward the side opposite to the suction port 12 is restricted by the washer 28. The movement is restricted by the support cylinder portion 14c.

Focusing on FIG. 2, the washer 28 can abut on the holding portion 20 from below, and the insertion hole 29 provided in the central portion of the washer 28 so as to allow the support shaft 8 to pass therethrough is A linear portion 29 a corresponding to the notch surface 23 of the support shaft 8 is provided on a part of the inner circumference, and is formed in a shape corresponding to the cross-sectional shape of the support shaft 8 . That is, the washer 28 does not rotate around the axis of the support shaft 8 fixedly supported by the casing 7, and contacts the holding portion 20 when the bearing means 27 moves toward the suction port 12 side. It is arranged so as to be in a substantially fixed position within the casing 7 by being in contact with it.

The bearing means 27 is composed of first and second slide bearings 30, 31 arranged between the washer 28 and the support tube portion 14c, the first slide bearing 30 connecting the washer 28 and the second slide. It is arranged between the bearings 31, and the second slide bearing 31 is arranged between the first slide bearing 30 and the support tube 14c.

The first slide bearing 30 has a first bearing cylinder portion 30a having a first inner hole 32 through which the support shaft 8 is inserted, and a sixth flange portion as a first restricting portion side flange portion facing the washer 28. A flange portion 30b is integrally provided.

Also referring to FIG. 3, the second slide bearing 31 includes a second bearing cylinder portion 31a having a second inner hole 33 through which the support shaft 8 is inserted, and a second bearing cylinder portion 31a facing the support cylinder portion 14c. A seventh flange portion 31b is integrally provided as a flange portion on the side of the second restricting portion.

On the inner surface of the first inner hole 32 of the first bearing sleeve portion 30a and the inner surface of the second inner hole 33 of the second bearing sleeve portion 31a, a First and second lubrication grooves 34 and 35 are formed between the support shaft 8 and the bearing means 27 to enable the fluid to be handled to flow. That is, the first end surface 30c of the sixth flange portion 30b facing the washer 28 is pressed against the washer 28 according to the pressure received by the impeller 9 when the impeller 9 rotates. When the impeller 9 is stopped, although it is closed, the concave portion 36 becomes open as the pressure contact of the first end surface 30c to the washer 28 is released. It is formed so as to communicate with the first lubricating groove 34 and to have a closed outer end along the radial direction.

Moreover, the first lubricating grooves 34 are formed at a plurality of locations, for example, three locations, spaced apart in the circumferential direction of the inner surface of the first inner hole 32, and the plurality of, for example, three recesses 36 are formed in a plurality of the above The outer diameter of the washer 28 is formed in the first end face 30c individually corresponding to the first lubrication grooves 34, and the outer diameter of the washer 28 is such that all the recesses 36 are covered when the first end face 30c is pressed against the washer 28. It is set to a size that can be closed.

Further, a discharge groove 37 communicating with the second lubrication groove 35 is formed on the end surface of the bearing means 27 on the support cylinder portion 14c side, that is, the second end surface 31c of the seventh flange portion 31b facing the support cylinder portion 14c. are formed to allow the fluid to be discharged radially outwardly.

Moreover, the second lubricating grooves 35 are formed at a plurality of locations, for example, three locations, spaced apart in the circumferential direction of the inner surface of the second inner hole 33, and the plurality of, for example, three discharge grooves 37 are formed at a plurality of locations. They are formed on the second end surface individually corresponding to the second lubrication grooves 35 .

Next, the action of the first embodiment will be described. Between the support shaft 8 and the impeller 9 and rotor 10, the impeller 9 and rotor 10 are fixed and a bearing that exhibits a sliding bearing function is provided. The means 27 includes a washer 28 arranged on the side of the intake port 12 of the casing 7 so as to be in a fixed position when the impeller 9 rotates, and a support cylinder fixedly arranged on the casing 7 at a position spaced from the intake port 12. A bearing means 27 is provided which is immersed in the fluid to be handled while allowing it to move between the portions 14c. The inner holes 32 and 33 have first and second lubrication grooves 34 and 35 which enable the fluid to be handled to flow between the support shaft 8 and the bearing means 27 over both ends of the bearing means 27 in the axial direction. is formed on the first end surface 30c of the bearing means 27 on the washer 28 side, and is closed by pressure contact of the first end surface 30c against the washer 28 according to the pressure received by the impeller 9 when the impeller 9 rotates. When the impeller 9 is stopped, the concave portion 36, which opens in response to the release of the pressure contact of the first end surface 30c to the washer 28, moves the radially inner end portion of the support shaft 8 to the first position. and the second lubrication grooves 34, 35, and formed to have a shape in which the outer end along the radial direction is closed. A discharge groove 37 communicating with the first and second lubricating grooves 34, 35 is formed to allow the fluid to be discharged radially outward.

Therefore, when the impeller 9 rotates, the first end surface 30c of the bearing means 27 on the washer 28 side is pressed against the washer 28 according to the pressure applied to the impeller 9, whereby the recess 36 formed in the first end surface 30c is formed. As a result, the flow of the handled fluid to the first and second lubricating grooves 34, 35 formed in the first and second inner holes 32, 33 of the bearing means 27 is blocked. On the other hand, when the impeller 9 stops, the pressure contact of the first end surface 30c to the washer 28 is released, so that the recess 36 is opened. The fluid to be handled can flow to the discharge groove 37 . That is, when the impeller 9 rotates, the handled fluid does not flow between the bearing means 27 and the support shaft 8, and when the impeller 9 stops, the handled fluid can flow between the bearing means 27 and the support shaft 8. For this reason, the fluid handled by the rotation of the impeller 9 is prevented from flowing between the bearing means 27 and the support shaft 8, and the foreign matter precipitates. The fluid to be handled is exchanged on the sliding surface of the bearing means 27 only when the impeller 9 is stopped. can be avoided, and the durability of the bearing means 27 can be improved.

Further, since the washer 28 cannot rotate, the first end surface 30c comes into sliding contact with the washer 28 so that the washer 28 receives the thrust load from the bearing means 27 side when the impeller 9 rotates. However, it is possible to lubricate between the first end face 30c and the washer 28 with the fluid to be handled accumulated in the recess 36 formed in the first end face 30c, thereby preventing breakage and abnormal wear and increasing resistance. It is possible to enhance the seizure property and improve the durability.

The bearing means 27 has a first bearing cylinder portion 30a having a first inner hole 32 in which a first lubricating groove 34 is formed, and a sixth lubricating groove 30a facing the washer 28 and having the recess 36 formed therein. A first sliding bearing 30 integrally provided with a flange portion 30b and a second bearing cylinder portion 31a having a second inner hole 33 in which a second lubrication groove 35 is formed are connected to the support cylinder portion 14c. Since the second sliding bearing 31 and the second slide bearing 31 integrally provided with the seventh flange portion 31b facing each other and formed with the discharge groove 37 are formed, the washer 28 and the support cylinder portion 14c, and the bearing By increasing the contact area with the means 27 and keeping the surface pressure low, the sliding resistance between the first sliding bearing 30 and the washer 28 can be reduced.

Furthermore, since the axis of the support shaft 8 is directed vertically with one end portion of the support shaft 8 held by the holding portion 20 positioned upward, when the impeller 9 is stopped, the gravity causes the first The end surface 30c can be spaced from the washer 28. As shown in FIG.

A second embodiment of the present invention will be described with reference to FIG. 4. This electric fluid pump is attached to a cylinder block for circulating cooling water in an internal combustion engine, for example, and has a pump chamber 41 inside. a support shaft 43 supported by the casing 42; an impeller 44 rotatably supported by the support shaft 43 and housed in the pump chamber 41; A rotor 45 housed in the pump chamber 41 and a stator 46 arranged to surround the rotor 45 outside the casing 42 are provided.

The casing 42 has a pump case 48 made of a light metal such as an aluminum alloy having a suction port 47 and a can-like shape coupled to the pump case 48 so as to form the pump chamber 41 between the pump case 48 and the pump case 48 . The case member 49 is made of a heat-resistant non-magnetic material, such as a synthetic resin such as PPS resin, capable of withstanding the temperature rise of the cooling water during operation of the internal combustion engine. A cover member 50 sandwiching the case member 49 and the pump case 48 is coupled to the pump case 48 and the case member 49 .

The stator 47 is fixed to the outer surface of the case member 49 so as to be covered with the cover member 50 , and the control circuit board 51 is accommodated and fixed in the cover member 50 .

At least one end of the support shaft 43 , in this embodiment, one end of the support shaft 43 is rotated by a holding portion 52 provided in the pump case 48 of the casing 42 and arranged inside the suction port 47 . The other end of the support shaft 43 is fitted into a support cylinder 49 a integrally provided with the case member 49 .

The rotor 45 is composed of a rotor hub 53 and a bond magnet 54 fixed to the rotor hub 53, and an extension tube forming a part of the rotor hub 53 so as to protrude from the bond magnet 54 and extend toward the impeller 44 side. The impeller 44 is integrally formed with the portion 53a.

The rotor 45 and the impeller 44 are rotatably supported by the support shaft 43 via a single sliding bearing 55 as bearing means. The sliding bearing 55 is disposed between a washer 60 as a first restricting portion facing the holding portion 52 through which the support shaft 43 is inserted, and the cylindrical support portion 49a as a second restricting portion. It has a cylindrical portion 55a, and the bearing cylindrical portion 55a is fitted into and fixed to the extending cylindrical portion 53a of the rotor hub 53 of the rotor 45. As shown in FIG. Further, an inner hole 56 through which the support shaft 43 is inserted is provided in the bearing cylinder portion 55a, and a lubricating groove 57 extending between both ends in the axial direction is formed in the inner surface of the inner hole 56. As shown in FIG.

A washer 60 is interposed between the holding portion 52 and the sliding bearing 55. A concave portion 58 facing the washer 60 side and a support cylindrical portion 49a side are provided on both axial end surfaces of the bearing cylinder portion 55a. Facing discharge grooves 59 are formed respectively. That is, the recess 58 is formed in the first end surface 55b of the sliding bearing 55 facing the washer 60, and the discharge groove 59 is formed in the second end surface 55c of the sliding bearing 55 facing the support cylinder portion 49a. be done.

According to the second embodiment, the same effects as those of the first embodiment can be obtained, and the number of parts can be reduced.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various design changes may be made without departing from the scope of the present invention described in the claims. is possible.

For example, in the above-described embodiment, as shown in FIGS. 1 and 4, the rotors 10, 45 and the stators 11, 46 are positioned substantially at the same position along the axis of the support shafts 8, 43 and radially , the invention is not limited to such an arrangement. For example, the rotor hubs 24 and 53 may be shortened so that the rotors 10 and 45 slightly protrude from the stators 11 and 46 toward the impellers 9 and 44 . Then, when the impellers 9 and 44 are stopped, the magnetic force between the stators 10 and 46 and the bond magnets 25 and 54 provided by the rotors 10 and 45 causes the first end faces 30c and 55b of the bearing means 27 and the slide bearing 55 to move regardless of gravity. can be separated from the washers 28 and 60, which are the first restricting portions.

Reference numerals 7, 42... Casings 8, 43... Support shafts 9, 44... Impellers 10, 45... Rotors 12, 47... Suction ports 14c, 49a... Supports that are second restricting portions Cylindrical portions 20, 52... Holding portion 27... Bearing means 28, 60... Washers 30, 31... sliding bearings 30a, 31a, 55a... Bearing tube portion 30b. .. 6th 5 flange portions 30c, 55b, which are first restricting portion side flange portions . . . 1st end face 31b . Second end faces 32, 33, 56 Inner holes 34, 35, 57 Lubrication grooves 36, 58 Recesses 37, 59 Discharge groove 55 Sliding bearings as bearing means

Claims (4)

Casings (7, 42) having suction ports (12, 47) and holding portions (20, 52) provided in the casings (7, 42) and arranged inside the suction ports (12, 47) A support shaft (8, 43) at least one end of which is held, and a cylindrical bearing cylinder (30a, 31a, 55a) to perform a sliding bearing function; Impeller (9, 44) and rotor (10, 45) fixed to means (27, 55) and in fixed position within said casing (7, 42) at least when said impeller (9, 44) rotates. Thus, the first restricting portion (28, 60) for restricting the movement of the bearing means (27, 55) toward the suction port (12, 47), and the suction port of the bearing means (27, 55) a second restricting portion (14c, 49a) fixedly arranged in the casing (7, 42) to restrict movement to the side opposite to (12, 47), and the bearing immersed in the handled fluid; In the electric fluid pump in which the means (27, 55) are axially movable between the first restricting portion (28, 60) and the second restricting portion (14c, 49a), the bushing portion (30a , 31a, 55a) on the inner surfaces of the inner holes (32, 33, 56) of the support shafts (8, 43) and the bearing means (27, 55) across the axial ends of the bearing means (27, 55). ) are formed between the lubricating grooves (34, 35, 57) that allow the fluid to be circulated between the first grooves (34, 35, 57) on the side of the first restricting portions (28, 60) of the bearing means (27, 55). The first restricting portions (28, 60) of the first end surfaces (30c, 55b) corresponding to the pressure received by the impellers (9, 44) during rotation of the impellers (9, 44) are provided on the end surfaces (30c, 55b). ), but when the impeller (9, 44) is stopped, the pressure contact of the first end face (30c, 55b) to the first restricting portion (28, 60) is released. The concave portions (36, 58) that are in the state communicate the radially inner end portions of the support shafts (8, 43) with the lubrication grooves (34, 35, 57) and the radially outer end portions thereof. is formed in a closed shape, and is formed on the second end surface (31c, 55c) of the bearing means (27, 55) on the side of the second restricting portion (14c, 49a). A bearing structure for an electric fluid pump, characterized in that discharge grooves (37, 59) communicating with said lubrication grooves (34, 35, 57) are formed so as to be able to discharge said handled fluid radially outward. . The bearing means (27) includes the first restricting portion (28) in the first bushing portion (30a) having the first inner hole (32) in which the first lubricating groove (34) is formed. A first sliding bearing (30) integrally provided with a first restricting portion-side flange portion (30b) in which the concave portion (36) is formed and facing the second lubricating groove (35) A second restricting portion facing the second restricting portion (14c) and formed with the discharge groove (37) in a second bushing portion (31a) having the second inner hole (33) formed therein. 2. A bearing structure for an electric fluid pump according to claim 1, further comprising a second sliding bearing (31) integrally provided with a side flange portion (31b). The bearing means (55) are provided in the recess ( 58) and the discharge groove (59) are formed respectively. The axes of the support shafts (8, 43) are oriented vertically with one end side of the support shafts (8, 43) held by the holding portions (20, 52) positioned upward. A bearing structure in an electric fluid pump according to any one of claims 1 to 3, characterized in that:

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