JP7240352B2 - electric pump - Google Patents

Description

The present invention relates to the structure of an electric pump that sucks and discharges fluid.

Internal combustion engines mounted on vehicles, especially four-wheeled vehicles, are generally water-cooled. Therefore, a cooling water pump for sucking and discharging cooling water for the internal combustion engine and for circulating the cooling water is attached to the internal combustion engine.

A known electric cooling water pump (see, for example, the following patent documents) includes a pump housing containing a pump chamber (vortex chamber) in which fluid, that is, cooling water inlet and outlet ports communicate, and an impeller disposed in the pump chamber. fixed to a rotating shaft, and a stator surrounding the rotor. Electromagnetic force generated between a permanent magnet provided on one of the rotor and the stator and a coil provided on the other rotates the rotor and thus the impeller, sucks cooling water from the suction port, and cools the cooling water. is pumped and ejected from the ejection port.

JP 2020-016182 A

In a conventional electric pump, the suction port of the pump housing opens in the axial direction of the rotating shaft of the rotor, and the discharge port opens in the radial direction orthogonal to the axial direction. Also, the rotor and stator are not mechanically connected. Rotating the rotor results in lower pressure on the inlet side and higher pressure on the outlet side. As a result, the rotor is drawn in along the axial direction toward the suction port and protrudes from the stator.

It is also conceivable to integrally form a boss on the pump housing to abut against the impeller from the suction port side to prevent the rotor from protruding. However, when it is attempted to manufacture a pump housing having such a shape, there is a tendency to increase the number of processing steps and increase the cost.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a structure capable of appropriately preventing the rotor from protruding during operation of an electric pump at as low cost as possible.

In the present invention, a pump housing including a pump chamber in which a fluid suction port and a fluid discharge port communicate with each other; a rotor having an impeller disposed in the pump chamber and fixed to a rotating shaft; a stator surrounding the rotor; a holding member separate from the pump housing and having a contact surface that abuts against the impeller along the axial direction of the rotating shaft from the suction port side; A boss having a shaft hole is provided, and one end of the rotating shaft of the rotor on the suction port side is inserted into the shaft hole to bear it. The surface facing the impeller is used as the abutment surface, and the pressing member has an outer shell formed annularly around the axis of the rotating shaft, and is in close contact with the outer shell and the peripheral edge of the suction port of the pump housing. An electric pump is constructed in which a labyrinth seal is provided between a seal body having a seal surface .

ADVANTAGE OF THE INVENTION According to this invention, the structure which can suppress protruding of a rotor appropriately during operation|movement of an electric pump can be implement|achieved at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS Sectional drawing which shows the structure of the electric pump of one Embodiment of this invention.

One embodiment of the present invention will be described with reference to the drawings. The electric pump 1 of the present embodiment is for sucking, discharging and circulating cooling water for a water-cooled internal combustion engine. As shown in FIG. 1, the electric pump 1 of the present embodiment includes a pump housing 2 including a pump chamber (vortex chamber) in which a suction port 21 and a discharge port (not shown) of cooling water, which is a fluid, communicate with each other; A rotor 3 having an impeller 32 arranged in a chamber fixed to a rotary shaft 31, a stator 4 surrounding the rotor 3, a motor housing 5 having a motor chamber containing the rotor 3 and the stator 4, and a pump housing 2. is provided with a seal body 6 and a bushing 7 interposed between the pump housing 2 and the impeller 32 as separate bodies.

In the pump housing 2 , a cooling water suction port 21 opens toward the axial center A direction of the rotating shaft 31 of the rotor 3 . On the other hand, the cooling water discharge port is opened in the radial direction perpendicular to the direction of the axis A of the rotating shaft 31 of the rotor 3, that is, in the direction perpendicular to the paper surface of FIG. does not appear in

The rotor 3 includes an impeller 32 fixed to one end of the rotating shaft 31 facing the suction port 21 and a permanent magnet 33 fixed to the other end separated from the suction port 21 . One end of the rotary shaft 31 of the rotor 3 is inserted into a shaft hole 74 formed in the central portion of the bush 7 to be borne. The other end of the rotating shaft 31 is inserted into a shaft hole 51 formed in the central portion of the motor housing 5 and is borne thereon. Bearings may be appropriately interposed between the rotating shaft 31 and each of the shaft holes 74 and 51 .

The stator 4 includes a coil 41 formed by winding a conductive wire around a core made of laminated magnetic steel plates.

The seal body 6 is a member that is separate and independent from the pump housing 2 (that is, detachable from the pump housing 2 ), is inserted into the pump housing 2 afterward, and is arranged in the vicinity of the suction port 21 . The seal body 6 is an annular body that is continuous around the axis A of the rotary shaft 31, and has an outer peripheral surface 61 that contacts or is very close to the inner peripheral surface of the pump housing 2, and the axial center A direction of the rotary shaft 31. It has a seal surface 62 that closely contacts the peripheral edge of the suction port 21 of the directional pump housing 2 .

The bushing 7 is also a member separate from the pump housing 2 and the seal body 6 (that is, detachable from the pump housing 2 and the seal body 6), and is inserted into the pump housing 2 and the seal body 6 afterward. , and arranged at a site near the suction port 21 . The bushing 7 includes an annular outer shell 71 continuous around the axis A of the rotating shaft 31, an annular boss 72 inside the outer shell 71 and continuous around the axis A of the rotating shaft 31, and the boss 72. A plurality of support arms 73 extending radially from the outer peripheral surface toward the inner peripheral surface of the outer shell 71 and connecting to both are provided. The shaft hole 74 is located in the center of the boss 72 . A labyrinth seal 75 is provided between the outer peripheral surface of the outer shell 71 of the bushing 7 and the inner peripheral surface of the seal body 6 that accommodates it.

The pump housing 2 and bushing 7 are keyed (or splined). That is, on the outer peripheral surface of the outer shell 71 of the bush 7, a key is formed that protrudes outward along the radial direction and extends along the axial center A direction. On the other hand, a concave groove (not shown) extending in the direction of the axis A is formed in the inner peripheral surface of the pump housing 2 that accommodates the pump housing 2 . When the bushing 7 is inserted into the pump housing 2 , the former key engages with the latter groove to prevent the bushing 7 from rotating about the axis A relative to the pump housing 2 .

Thus, the surface of the boss 72 of the bush 7 that faces the rotor 3 along the direction of the axis A of the rotating shaft 31 serves as a contact surface that contacts the impeller 32 . A washer 76 is interposed between the contact surface and the impeller 32 .

As with the known electric pump, the electric pump 1 of this embodiment also energizes the coil 41 to generate an electromagnetic force between the rotor 3 and the stator 4 to rotate the rotor 3 and thus the impeller 32 . 1, the cooling water flows into the pump chamber from the suction port 21 of the pump housing 2, and flows into the inner spaces of the seal body 6 and the bush 7, particularly the outer shell 71 and the boss. 72, it reaches the periphery of the impeller 32, is pressure-fed by the impeller 32, and flows out of the pump chamber from the discharge port.

The rotor 3 and stator 4 are not mechanically connected. Therefore, when the electric pump 1 is operated by rotating the rotor 3, the rotor 3 including the impeller 32 moves along the direction of the axis A due to the pressure difference between the pressure on the suction port 21 side and the pressure on the discharge port side. 21 side is drawn in. However, in the present embodiment, the impeller 32 contacts the contact surface of the boss 72 of the bush 7 , more specifically, the washer 76 , so that the impeller 32 rotates while sliding against the washer 76 . Displacement of the rotor 3 to the suction port 21 side and protruding from the stator 4 is suppressed.

As already mentioned, a labyrinth seal 75 is provided between the outer peripheral surface of the outer shell 71 of the bushing 7 and the inner peripheral surface of the seal body 6 . The presence of the labyrinth seal 75 suppresses leakage (or reverse flow) of cooling water from the discharge port side to the suction port 21 side through the space between the outer circumference of the outer shell 71 of the bush 7 and the inner circumference of the seal body 6 . . Furthermore, since the seal surface 62 of the seal body 6 is in close contact with the periphery of the suction port 21 of the pump housing 2, the cooling water is sucked from the discharge port side through the gap between the outer periphery of the seal body 6 and the inner periphery of the pump housing 2. Leakage to the mouth 21 side is also suppressed. Overall, the efficiency of the electric pump 1 can be maintained at a high level.

In this embodiment, a pump housing 2 including a pump chamber in which a fluid suction port 21 and a fluid discharge port communicate with each other; a rotor 3 having an impeller 32 disposed in the pump chamber fixed to a rotating shaft 31; and a contact surface (washer 76) that abuts against the impeller 32 along the axial center A direction of the rotating shaft 31 from the suction port 21 side. An electric pump 1 including a holding member (bush 7) forming a body is constructed.

According to this embodiment, it is possible to appropriately prevent the rotor 3 from protruding during operation of the electric pump 1 . Moreover, the shape of the pump housing 2 does not become unnecessarily complicated, the design of the mold for molding the pump housing 2 and the removal of the mold are easy, and the number of processing steps when manufacturing the pump housing 2 does not increase. , without incurring higher costs.

For the labyrinth seal 75, tolerance control and dimensional accuracy along the radial direction perpendicular to the direction of the axis A should be strictly enforced. That is, it is not necessary to extremely improve the dimensional accuracy along the axis A direction between the bush 7 and the seal body 6 and between the bush 7 and the pump housing 2 . This is because a tight seal is formed between the seal surface 62 of the seal body 6 and the periphery of the suction port 21 of the pump housing 2 .

The present invention is not limited to the embodiments detailed above. For example, the fluid sucked and discharged by the electric pump according to the present invention is not limited to the cooling water of the internal combustion engine.

In addition, the specific configuration of each part and the content of processing can be modified in various ways without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1... Electric pump 2... Pump housing 21... Suction port 3... Rotor 31... Rotating shaft 32... Impeller 4... Stator 7... Holding member (bush)
76 ... Contact surface (washer)
A … the axis of the rotating shaft

Claims (1)

a pump housing containing a pump chamber in which a fluid suction port and a fluid discharge port are in communication;
a rotor formed by fixing an impeller disposed in the pump chamber to a rotating shaft;
a stator surrounding the rotor;
a holding member separate from the pump housing and having a contact surface that abuts against the impeller along the axial direction of the rotating shaft from the suction port side ;
The pressing member has a boss having an axial hole therein,
one end of the rotating shaft of the rotor on the side of the suction port is inserted into the shaft hole to bear it;
a surface of the boss facing toward the impeller along the axial direction of the rotating shaft is defined as the contact surface;
The pressing member has an outer shell formed annularly around the axis of the rotating shaft, and a labyrinth seal is provided between the outer shell and a seal body having a sealing surface that comes in close contact with the peripheral edge of the suction port of the pump housing. electric pump.

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