Patent Description:
In the related art, a submersible pump including an impeller is known. Such a submersible pump is disclosed in <CIT>, <CIT>, <CIT>, and <CIT>.

<CIT> discloses a submersible pump casing made of an elastic material such as hard rubber or synthetic resin. The pump includes a pump chamber housing an impeller, a discharge chamber communicating with the pump chamber, and a water-separating portion that guides part of the swirling fluid into the discharge chamber. The casing has an open-top cylindrical structure covered by an upper lid. To prevent the deformation or breakage of the water-separating portion, <CIT> introduces reinforcing projections on the upper surface of the water-separating portion, which engage with corresponding recesses on the upper lid.

<CIT> discloses a compact submersible pump with a cylindrical casing divided into upper and lower sections, housing a centrally positioned motor connected to an impeller. The motor shaft is offset relative to the casing's center to optimize space, and a water passage extends alongside the motor. Upper and lower flow plates guide the fluid, ensuring controlled flow. The components are secured using a threaded fastening mechanism, which provides structural stability and facilitates assembly.

<CIT> discloses a submersible pump comprising a pump housing with a pump inlet and a pump outlet. The invention integrates a pressure switch actuated by the pressure in the pump outlet and a check valve positioned upstream of the pump outlet to regulate fluid flow. The check valve is a flap valve supported by a compression spring within the pump outlet. A key feature is a multifunctional plastic component that serves as a check valve, pressure membrane, cable sealing, and housing seal, improving compactness and manufacturing efficiency.

In <CIT>, a submersible motor pump (so-called one-sided waterway pump) in which a flow path extending along a rotation shaft is provided on one side of a submersible pump main body is disclosed. The submersible motor pump is configured to suck water from a suction port provided in a pump casing by rotating an impeller provided at a lower end of the rotation shaft, and send water toward an upper discharge port via a flow path on one side of the submersible pump main body.

Although not specified in <CIT>, in the field of a submersible pump (so-called one-sided waterway pump) in which a flow path is provided on one side of the submersible pump main body, in the related art, it has been desired to increase the total head, and there is a problem of how to increase the total head. Even in the submersible motor pump disclosed in <CIT>, there is a problem of how to increase the total head.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a submersible pump capable of increasing the total head.

In order to achieve the object, a submersible pump according to the present invention is a submersible pump in which a one-sided waterway extending along a rotation shaft is provided on one side of a submersible pump main body, and includes an impeller attached to one end of the rotation shaft; and a pump casing in which the impeller is arranged, in which the pump casing includes a tongue portion that is arranged between a pump chamber in which the impeller is arranged and an inlet opening of the one-sided waterway when viewed from an axial direction of the rotation shaft, and a connection waterway that is provided between the tongue portion and an inner surface of the pump casing, and is directly connected to the inlet opening from an upstream side when viewed from the axial direction of the rotation shaft.

In the submersible pump according to the present invention, as described above, the pump casing is provided with the tongue portion that is arranged between the pump chamber in which the impeller is arranged and the inlet opening of the one-sided waterway when viewed from the axial direction of the rotation shaft, and the connection waterway that is provided between the tongue portion and the inner surface of the pump casing, and is directly connected to the inlet opening from the upstream side when viewed from the axial direction of the rotation shaft. Thereby, the pump chamber and the one-sided waterway can be connected to each other via the connection waterway. Therefore, as compared with a case where the pump chamber and the one-sided waterway are directly connected, in the connection waterway provided immediately before the one-sided waterway, since the water flow (flow path sectional area) is narrowed down and the water flow is regulated, water can smoothly flow into the one-sided waterway at a faster speed. As a result, the total head of the submersible pump can be further increased.

In the submersible pump according to the present invention, the one-sided waterway is formed such that a flow path sectional area is gradually decreased from a downstream side toward the inlet opening on the upstream side. With this configuration, in the inlet opening of the one-sided waterway, the water flow (flow path sectional area) can be narrowed down, so that water can flow into the one-sided waterway at a faster speed. Further, by changing the flow path sectional area of the one-sided waterway so that the flow path sectional area is gradually decreased instead of being suddenly changed, it is possible to suppress the water flow from being disturbed by the sudden change of the flow path sectional area. As a result, the total head of the submersible pump can be further increased.

In the submersible pump according to the present invention, a motor including a motor frame provided to the pump casing from a side opposite to a suction port in the axial direction is further provided, and the one-sided waterway is formed to straddle the motor frame and the pump casing, and is formed such that the flow path sectional area is gradually decreased from the motor frame on the downstream side toward the pump casing on the upstream side. With this configuration, not only the one-sided waterway provided in the pump casing but also the one-sided waterway provided in the motor frame can be formed so that the flow path sectional area is gradually decreased, and therefore, the one-sided waterway can be formed over a relatively large range such that the flow path sectional area is gradually decreased. Therefore, the sudden change of the flow path sectional area can be further suppressed, and thus the total head of the submersible pump can be further increased.

It is preferable that the impeller includes a plate-shaped portion, and a blade portion provided on a suction port side of the plate-shaped portion, and a portion on an inner peripheral side of the blade portion is inclined toward an outer peripheral side. With this configuration, on the inner peripheral side of the blade portion, a larger opening portion on the inner peripheral side where water is first taken into a portion between the blade portions via the suction port can be secured by inclining the blade portion toward the outer peripheral side. Therefore, the loss on the large flow rate side can be reduced by improving the suction performance, and the lift on the large flow rate side can be increased.

It is preferable that the blade portion is formed such that a size of the blade portion in the axial direction is gradually decreased from the inner peripheral side toward the outer peripheral side of the impeller, and a facing surface of the pump casing facing the blade portion is inclined from the inner peripheral side toward the outer peripheral side of the impeller corresponding to the size of the blade portion in the axial direction, which is gradually decreased, when viewed from a direction orthogonal to the axial direction. With this configuration, the loss can be reduced by changing an area ratio between the inlet side and the outlet side in the pump casing, and therefore the total head of the submersible pump can be further increased.

In the preferable configuration in which the portion on the inner peripheral side of the blade portion is inclined toward the outer peripheral side, it is further preferable that the impeller is formed such that a flow path sectional area of a waterway formed between the blade portions is gradually decreased from the inner peripheral side to the outer peripheral side of the impeller. With this configuration, the outer diameter of the impeller can be increased by making the blade width on the outer peripheral side (outlet side) smaller than the blade width on the inner peripheral side (inlet side), and therefore the total head of the submersible pump in the small flow rate range can be further increased.

It is preferable that an inner surface of the one-sided waterway is formed in a smooth shape without a step between the motor frame and a discharge port. With this configuration, unlike a case where there is a step, it is possible to prevent a water flow passing through the one-sided waterway from being disturbed, and thus the total head of the submersible pump can be further increased.

It is preferable that the tongue portion extends toward the upstream side of the inlet opening so that the vicinity of a center of the pump chamber is partitioned off from the inlet opening of the one-sided waterway when viewed from the axial direction of the rotation shaft. With this configuration, the connection waterway can be arranged to extend in a direction along the water flow generated in the pump chamber by the impeller instead of in a direction in which the vicinity of the center of the pump chamber and the inlet opening of the one-sided waterway are directly connected. Therefore, water can flow smoothly from the pump chamber to the connection waterway at a higher speed, and therefore, the total head of the submersible pump can be further increased.

It is preferable that the pump casing includes a surface that is formed on the other end side of the rotation shaft with respect to the connection waterway, and forms the connection waterway, and the surface forming the connection waterway connects the tongue portion and the inner surface of the pump casing to each other when viewed from the axial direction of the rotation shaft. With this configuration, the number of components can be reduced and the device configuration can be simplified as compared with a case where the upper surface that forms the connection waterway by connecting the tongue portion and the inner surface of the pump casing when viewed from the axial direction of the rotation shaft is configured by a lid-shaped separate member different from the pump casing.

It is preferable that the motor frame is provided with a reduced portion of which an external shape is gradually decreased from the downstream side toward the upstream side along with the flow path sectional area of the one-sided waterway being gradually decreased from the motor frame on the downstream side toward the pump casing on the upstream side. With this configuration, the fixing member for the pump casing and the motor frame can be arranged at a position closer to the one-sided waterway, by the space around the reduced portion, which is secured on the pump casing side by the reduced portion. Therefore, water leakage from between the pump casing and the motor frame can be effectively suppressed by firmly fixing the pump casing and the motor frame.

According to the present invention, as described above, it is possible to provide a submersible pump capable of further increasing the total head.

A submersible pump <NUM> of the present embodiment will be described with reference to <FIG>. The submersible pump <NUM> is a vertical electric pump in which a center axis of rotation α of a rotation shaft <NUM> extends in a vertical direction (Z direction). Further, the submersible pump <NUM> is a so-called one-sided waterway pump in which a one-sided waterway <NUM> extending along the rotation shaft <NUM> is provided on one side of a submersible pump main body 100a. As an example, the submersible pump <NUM> of the present embodiment is used at a site where a particularly large total head is required, such as a tunnel work site in a mountain.

The one-sided waterway <NUM> illustrated in <FIG> is a waterway through which water in a pump chamber 5a flows toward a discharge port 101b. The one-sided waterway <NUM> is formed to straddle each member of a pump casing <NUM>, a motor frame <NUM>, and a bracket <NUM>, which will be described later. That is, a portion of the uppermost stream of the one-sided waterway <NUM> is formed in the pump casing <NUM>. A portion of the downmost stream of the one-sided waterway <NUM> is formed in the bracket <NUM>. A portion of the one-sided waterway <NUM> located between the pump casing <NUM> and the bracket <NUM> is formed in the motor frame <NUM>.

In each figure, a direction in which the center axis of rotation α of the rotation shaft <NUM> extends is indicated by the Z direction, a direction facing a motor <NUM> side from an impeller <NUM> side in the Z direction is indicated by a Z1 direction (upward), and the opposite direction to the Z1 direction (downward) is indicated by a Z2 direction. Further, a radial direction of the rotation shaft <NUM> (impeller <NUM>) is indicated by an R direction. The R direction is orthogonal to the Z direction.

The submersible pump <NUM> includes the rotation shaft <NUM>, the motor <NUM>, a hose coupling <NUM> attached to the discharge port 101b, the impeller <NUM>, the pump casing <NUM> in which the impeller <NUM> is arranged, and the above-mentioned one-sided waterway <NUM>. At a lower portion of the submersible pump <NUM>, a strainer <NUM> that prevents the suction of foreign matter and functions as a stand for the submersible pump <NUM> to stand upright is provided. In some cases, a pipe is connected to the discharge port 101b without providing the hose coupling <NUM>.

The rotation shaft <NUM> generally has a cylindrical shape extending in the vertical direction (Z direction). The impeller <NUM> is attached to one end 10a (lower end) of the rotation shaft <NUM> in the Z2 direction, and the motor <NUM> (rotor <NUM>) is fixed to the other end 10b (upper end) side of the rotation shaft <NUM> in the Z1 direction. The rotation shaft <NUM> has a function of transmitting the driving force of the motor <NUM> to the impeller <NUM>.

The rotation shaft <NUM> has a contact surface <NUM> that abuts on the end surface of the impeller <NUM> in the Z1 direction. The contact surface <NUM> has a function of positioning the impeller <NUM> with respect to the rotation shaft <NUM> in the Z direction. Further, the rotation shaft <NUM> is configured such that the impeller <NUM> is fitted from the lower side of the rotation shaft <NUM> and a key member (not illustrated) is installed in a gap between the rotation shaft <NUM> and the impeller <NUM>. Thereby, the rotation shaft <NUM> is configured so that the impeller <NUM> is positioned with respect to the rotation shaft <NUM>. As a result, the rotations of the rotation shaft <NUM> and the impeller <NUM> are synchronized.

The motor <NUM> is configured to rotationally drive the rotation shaft <NUM>. The motor <NUM> is configured to rotationally drive the impeller <NUM> via the rotation shaft <NUM>. Specifically, the motor <NUM> includes a stator <NUM> having a coil, the rotor <NUM> arranged on the inner peripheral side of the stator <NUM>, the motor frame <NUM>, an upper bearing 23a, a lower bearing 23b, and the bracket <NUM>. The rotation shaft <NUM> is also included in the motor <NUM>.

The rotation shaft <NUM> is fixed to the rotor <NUM>. The motor <NUM> is configured to rotationally drive the rotation shaft <NUM> together with the rotor <NUM> by generating a magnetic field with the stator <NUM>. The motor frame <NUM> covers the stator <NUM> and the rotor <NUM>. The upper bearing 23a and the lower bearing 23b rotatably support the upper side and the lower side of the rotation shaft <NUM>, respectively. The upper bearing 23a is installed on the bracket <NUM>. The bracket <NUM> is fixed to the motor frame <NUM> from above. The lower bearing 23b is configured of two angular contact ball bearings that are vertically overlapped with each other and have different orientations from each other. By configuring the lower bearing 23b in this way, it is possible to handle axial loads with different orientations in both directions, and it is possible to handle axial loads in any cases of the small flow rate side and the large flow rate side.

The motor frame <NUM> is installed with respect to the pump casing <NUM> from the side (upper side) opposite to a suction port 101a side in the axial direction (Z direction) of the rotation shaft <NUM>. The motor frame <NUM> has a frame portion 22a forming a motor chamber 2a in which the stator <NUM> and the rotor <NUM> are arranged, and a frame portion 22b forming a portion of the one-sided waterway <NUM>.

Both the frame portion 22a and the frame portion 22b are formed in a cylindrical shape provided with through-holes penetrating the frame portions in the vertical direction. The frame portion 22b is arranged on the outer peripheral side of the frame portion 22a in the radial direction (R direction) of the rotation shaft <NUM> (impeller <NUM>).

The bracket <NUM> forms a portion of the downmost stream of the one-sided waterway <NUM>. The bracket <NUM> is provided with the discharge port 101b that is inclined with respect to a horizontal direction (direction orthogonal to the Z direction). The hose coupling <NUM> is attached to the bracket <NUM> from above so as to cover the discharge port 101b.

The hose coupling <NUM> has a shape obtained by cutting a cylindrical shape diagonally. That is, the hose coupling <NUM> has an inclined end surface <NUM> that is inclined with respect to a direction in which the cylindrical shape extends.

The hose coupling <NUM> is fixed to the bracket <NUM> by a fixing member F. The inclined end surface <NUM> of the hose coupling <NUM> faces the bracket <NUM> from above in a state where the hose coupling <NUM> is fixed to the bracket <NUM> by the fixing member F.

The hose coupling <NUM> is configured to be able to switch a flow direction of the water discharged from the discharge port 101b by being rotated with respect to the discharge port 101b while causing the inclined end surface <NUM> to face the bracket <NUM> after the fixing by the fixing member F is released. Specifically, the hose coupling <NUM> is configured to be able to switch between a state in which the water discharged from the discharge port 101b flows directly above the discharge port 101b and a state in which the water discharged from the discharge port 101b flows in a direction inclined by a predetermined angle θ with respect to directly above the discharge port 101b.

As illustrated in <FIG>, the impeller <NUM> is arranged in the pump chamber 5a inside the pump casing <NUM>. The impeller <NUM> is a semi-open type impeller. That is, the impeller <NUM> includes a plate-shaped portion (shroud) <NUM>, and a plurality of blade portions (vanes) <NUM> provided on the suction port 101a side (lower side) of the plate-shaped portion <NUM>.

Further, the impeller <NUM> is provided with a back blade 4a on the upper side (side opposite to the blade portion <NUM> side) of the plate-shaped portion <NUM>. The back blade 4a has a function of suppressing a downward load acting on the impeller <NUM>. That is, the back blade 4a has a function of suppressing the load acting on the bearing during the pump operation.

Further, a labyrinth seal LS is provided between the impeller <NUM> and the pump casing <NUM>, and a space <NUM> is provided between the pump chamber 5a and an oil chamber <NUM>. Therefore, it is avoided that the pressure in the pump chamber 5a is directly applied to the oil chamber <NUM>. The leakage of water from the pump chamber 5a to the space <NUM> is increased as the pressure in the pump chamber 5a is increased, and thus the amount of water discharged from the pump casing <NUM> is decreased. By arranging the labyrinth seal LS between the pump chamber 5a and the space <NUM>, the leakage from the pump chamber 5a to the space <NUM> can be reduced, and thus a large amount of water can be discharged from the pump casing <NUM> even in a case of the high pressure.

The plate-shaped portion <NUM> is formed in a circular flat plate shape extending in a direction orthogonal to the Z direction.

The blade portion <NUM> is formed so that a size D in the axial direction (Z direction) is gradually decreased from the inner peripheral side toward the outer peripheral side of the impeller <NUM>. That is, the impeller <NUM> (impeller <NUM>) is formed in a mountain shape (arc shape) so that the inner peripheral side of the impeller <NUM> protrudes downward (Z2 direction) in the side view.

In the blade portion <NUM>, a portion 41a on the inner peripheral side of the blade portion <NUM> is inclined toward the outer peripheral side. That is, the portion 41a on the inner peripheral side of the blade portion <NUM> is inclined so as to be gradually separated from the rotation shaft <NUM> toward the lower end (end portion in the Z2 direction) of the blade portion <NUM> from the base of the blade portion <NUM> connected to the plate-shaped portion <NUM>.

Since the impeller <NUM> is configured such that the blade width of the blade portion <NUM> is narrowed toward the outer peripheral side of the impeller <NUM> in the sectional view (refer to <FIG>), a flow path sectional area S1 of a waterway <NUM> formed between the blade portions <NUM> is formed to be gradually decreased from the inner peripheral side to the outer peripheral side of the impeller <NUM>. That is, the impeller <NUM> is formed such that a large amount of water can be taken on the inner peripheral side where the water is taken into the waterway <NUM> between the plurality of blade portions <NUM> via the suction port 101a.

Further, the impeller <NUM> is formed such that the flow velocity of the water can be increased on the outer peripheral side where the water is discharged from the waterway <NUM> between the plurality of blade portions <NUM> to the outside of the impeller <NUM>. Therefore, the submersible pump <NUM> is configured to be able to increase the total head by vigorously introducing water into the one-sided waterway <NUM>.

As illustrated in <FIG>, in the pump casing <NUM>, the impeller <NUM> is arranged inside, and the pump chamber 5a is provided inside. The pump casing <NUM> forms a portion of the uppermost stream of the one-sided waterway <NUM>. That is, the pump casing <NUM> is provided with an inlet opening 6a for introducing water from the pump chamber 5a into the one-sided waterway <NUM>. In <FIG>, for convenience of explanation, the pump casing <NUM> is illustrated in a divided state (section), and the impeller <NUM> is illustrated in an undivided state.

The pump casing <NUM> includes a pump casing main body <NUM>, and a suction cover <NUM> that is detachably attached to the pump casing main body <NUM>.

The suction cover <NUM> has the suction port 101a. The suction cover <NUM> is removed from the pump casing main body <NUM> in a case where the impeller <NUM> is attached to the rotation shaft <NUM>.

A facing surface <NUM> of the pump casing <NUM> (suction cover <NUM>) facing the blade portion <NUM> from below is inclined from the inner peripheral side toward the outer peripheral side of the impeller <NUM> corresponding to the size of the blade portion <NUM> in the axial direction, which is gradually decreased from the inner peripheral side toward the outer peripheral side, when viewed from a direction orthogonal to the axial direction (Z direction) of the rotation shaft <NUM> (in the side view).

That is, the facing surface <NUM> of the pump casing <NUM> (suction cover <NUM>) is arranged with a substantially constant relatively small gap from the lower end of the blade portion <NUM> in the side view. Therefore, the facing surface <NUM> of the pump casing <NUM> (suction cover <NUM>) is formed to be inclined along the blade portion <NUM> which is gradually decreased from the inner peripheral side toward the outer peripheral side of the impeller <NUM> in the side view.

The pump casing <NUM> (pump casing main body <NUM>) includes a tongue portion <NUM> and a connection waterway (throat) <NUM>.

The tongue portion <NUM> is arranged between the pump chamber in which the impeller <NUM> is arranged and the inlet opening 6a of the one-sided waterway <NUM> when viewed from the axial direction (Z direction) of the rotation shaft <NUM>. The tongue portion <NUM> is a spiral cut-off portion for collecting water discharged from the waterway <NUM> between the blade portions <NUM> of the impeller <NUM>, in the pump casing <NUM>.

The tongue portion <NUM> extends toward the upstream side of the inlet opening 6a so that the vicinity of the center of the pump chamber 5a (near the center axis of rotation α of the rotation shaft <NUM>) is partitioned off from the inlet opening 6a of the one-sided waterway <NUM> when viewed from the axial direction (Z direction) of the rotation shaft <NUM>.

That is, when viewed from the axial direction (Z direction) of the rotation shaft <NUM>, in a case where the center axis of rotation α of the rotation shaft <NUM> and the inlet opening 6a are connected by a straight line L, the pump casing <NUM> is configured such that the tongue portion <NUM> is always positioned on the straight line L connecting the center axis of rotation α and the inlet opening 6a.

The connection waterway <NUM> is a waterway connecting the pump chamber 5a and the one-sided waterway <NUM>. The connection waterway <NUM> is provided between the tongue portion <NUM> and an inner surface <NUM> of the pump casing <NUM> when viewed from the axial direction (Z direction) of the rotation shaft <NUM>. The inner surface <NUM> of the pump casing <NUM> is arranged on the outer peripheral side of the tongue portion <NUM> in the radial direction (R direction) of the rotation shaft <NUM> (impeller <NUM>) when viewed from the axial direction of the rotation shaft <NUM>. The connection waterway <NUM> is directly connected to the inlet opening 6a from the upstream side.

The pump casing <NUM> includes an upper surface 56a that is provided on the other end 10b side (Z1 direction side) of the rotation shaft <NUM> with respect to the connection waterway <NUM>, and forms the connection waterway <NUM>. The upper surface 56a forming the connection waterway <NUM> connects the inner surface <NUM> of the pump casing <NUM> and the tongue portion <NUM> to each other when viewed from the axial direction of the rotation shaft <NUM>. The upper surface 56a is an example of a "surface" in the claims.

Further, the pump casing <NUM> includes a lower surface 56b (refer to <FIG>) that is provided on the one end 10a side (Z2 direction side) of the rotation shaft <NUM> with respect to the connection waterway <NUM>, and forms the connection waterway <NUM>. The connection waterway <NUM> is formed in a tubular shape connecting the pump chamber 5a and the one-sided waterway <NUM> by being surrounded by the tongue portion <NUM>, the inner surface <NUM>, the upper surface 56a, and the lower surface 56b.

As illustrated in <FIG>, the oil chamber <NUM> is provided between the motor <NUM> and the pump chamber 5a. A mechanical seal <NUM> and an oil lifter <NUM> are installed in the oil chamber <NUM>. Further, although not illustrated, an electrode-type water immersion detection unit may be arranged in the oil chamber <NUM>.

The pump casing <NUM> and the motor frame <NUM> are in direct contact with each other at a contact portion C on the outer peripheral side of the oil chamber <NUM> so that the oil chamber <NUM> is not directly sandwiched between the pump casing <NUM> and the motor frame <NUM>. Thereby, the submersible pump <NUM> can reduce the component tolerances that have to be taken into consideration, so that high assemblability can be ensured.

As illustrated in <FIG>, a pair of small flange portions FL1 and one large flange portion FL2 (refer to also <FIG>) are provided at the upper end portion of the pump casing <NUM>. The small flange portions FL1 and one large flange portion FL2 are configured to fix the pump casing <NUM> to the motor frame <NUM>. Each of the pair of small flange portions FL1 is provided with one screw hole H10 for the attachment of the fixing member. The one-sided waterway <NUM> is arranged inside the large flange portion FL2 so as to penetrate the large flange portion FL2.

Here, in <FIG> and <FIG>, a direction in which the rotation shaft <NUM> and the one-sided waterway <NUM> are lined up is indicated by an A direction, and a direction orthogonal to the A direction is indicated by a B direction. Both the A direction and the B direction are orthogonal to the Z direction.

The large flange portion FL2 is provided with a pair of screw holes H20 for the attachment of a fixing member Fa (refer to <FIG>), and a pair of screw holes H21 for the attachment of a fixing member Fb (refer to <FIG>).

The pair of screw holes H20 are arranged near both end portions of the large flange portion FL2 in the B direction and on the inner peripheral side of the large flange portion FL2.

The pair of screw holes H21 are arranged in the vicinity of the outer peripheral end portion of the large flange portion FL2. Further, the pair of screw holes H21 are arranged inward of the pair of screw holes H20 in the B direction. That is, the pair of screw holes H21 are arranged at positions closer to the one-sided waterway <NUM> than the pair of screw holes H20 in the B direction. Further, the pair of screw holes H21 are arranged inside a range in which the one-sided waterway <NUM> is provided, in the B direction.

The arrangement of the screw holes H21 close to the one-sided waterway <NUM> is realized by a space that is secured around a reduced portion 22c of the motor frame <NUM> (a portion on the Z2 direction side where the external shape of the reduced portion 22c becomes smaller) which will be described later, by the reduced portion 22C. Further, the space secured around the reduced portion 22c enables the insertion (attachment) of the fixing members Fa and Fb from above (motor frame <NUM>).

In this way, in the submersible pump <NUM>, since the pump casing <NUM> and the motor frame <NUM> are fixed by the fixing member Fa at a position close to the one-sided waterway <NUM>, water leakage from between the pump casing <NUM> and the motor frame <NUM> can be effectively suppressed by firmly fixing the pump casing <NUM> and the motor frame <NUM>.

Here, packing P is installed between the pump casing <NUM> and the motor frame <NUM> in a range indicated by the two-dot chain line. As illustrated in <FIG>, in the submersible pump <NUM>, since the screw holes at the outer peripheral end portion of the large flange portion FL2 are provided at the positions indicated by H21, an area required for the packing P can be decreased as compared with a case where the screw holes are provided near the positions indicated by hatching in <FIG>, and thus the pressure applied to the packing P can be made larger than the pressure in the related art. As a result of optimizing the position of the screw holes by providing the reduced portion 22c, the submersible pump <NUM> can secure a watertight state by the packing P more reliably than that in the related art.

As illustrated in <FIG>, the one-sided waterway <NUM> is formed so that a flow path sectional area S2 is gradually decreased from the downstream side toward the inlet opening 6a on the upstream side. In other words, the one-sided waterway <NUM> is formed in a widening shape in which the flow path sectional area S2 is gradually increased from the inlet opening on the upstream side toward the downstream side.

Specifically, the one-sided waterway <NUM> is formed to straddle the motor frame <NUM> and the pump casing <NUM> as described above, and is formed such that the flow path sectional area S2 is gradually decreased from the motor frame <NUM> on the downstream side toward the pump casing <NUM> on the upstream side.

That is, the one-sided waterway <NUM> is formed so that a path through which water passes is narrowed in the vicinity of the inlet opening 6a. Therefore, the one-sided waterway <NUM> can increase the flow velocity of water in the vicinity of the inlet opening 6a. As described above, the submersible pump <NUM> is configured to be able to increase the total head by being formed to vigorously introduce water into the one-sided waterway <NUM>.

The motor frame <NUM> is provided with the reduced portion 22c of which the external shape is gradually decreased from the downstream side toward the upstream side along with the flow path sectional area of the one-sided waterway <NUM> being gradually decreased from the motor frame <NUM> on the downstream side toward the pump casing <NUM> on the upstream side (refer to <FIG>). The reduced portion 22c is a lower portion of the frame portion 22b. In this way, it is possible to improve the pump performance by providing the reduced portion 22c in which the flow path is narrowed, and it is possible to increase an area in which the water flowing through the flow path is in contact with the component inside the motor <NUM> and improve the cooling performance for the motor <NUM> by providing the frame 22b in which the width of the flow path is widened.

An inner surface <NUM> of the one-sided waterway <NUM> is formed in a smooth shape without a step (smoothed shape) between the motor frame <NUM> and the discharge port 101b. That is, the inner surface <NUM> of the one-sided waterway <NUM> is formed in a smooth shape without a step in a portion of the downmost stream provided in the bracket <NUM>.

The inner surface <NUM> of the one-sided waterway <NUM> is also formed in a smooth shape without a step in a portion on the upstream side provided in the pump casing <NUM> and the motor frame <NUM>. As described above, the submersible pump <NUM> is configured to be able to increase the total head by forming the inner surface <NUM> in a smooth shape without a step and reducing the energy loss of water in the one-sided waterway <NUM>.

In the present embodiment, the following effects can be obtained.

In the present embodiment, as described above, the pump casing <NUM> is provided with the tongue portion <NUM> which is arranged between the pump chamber 5a in which the impeller <NUM> is arranged and the inlet opening 6a of the one-sided waterway <NUM> when viewed from the axial direction of the rotation shaft <NUM>, and the connection waterway <NUM> which is arranged between the tongue portion <NUM> and the inner surface <NUM> of the pump casing <NUM> is directly connected to the inlet opening 6a from the upstream side when viewed from the axial direction of the rotation shaft <NUM>. Thereby, the pump chamber 5a and the one-sided waterway <NUM> can be connected to each other via the connection waterway <NUM>. Therefore, as compared with a case where the pump chamber 5a and the one-sided waterway <NUM> are directly connected, in the connection waterway <NUM> provided immediately before the one-sided waterway <NUM>, since the water flow (flow path sectional area) is narrowed down and the water flow is regulated, water can smoothly flow into the one-sided waterway <NUM> at a faster speed. As a result, the total head of the submersible pump <NUM> can be further increased.

In the present embodiment, as described above, the one-sided waterway <NUM> is formed so that a flow path sectional area S2 is gradually decreased from the downstream side toward the inlet opening 6a on the upstream side. Thereby, in the inlet opening 6a of the one-sided waterway <NUM>, the water flow (flow path sectional area S2) can be narrowed down, so that water can flow into the one-sided waterway <NUM> at a faster speed. Further, by changing the flow path sectional area S2 of the one-sided waterway <NUM> so that the flow path sectional area S2 is gradually decreased instead of being suddenly changed, it is possible to suppress the water flow from being disturbed by the sudden change of the flow path sectional area S2. As a result, the total head of the submersible pump <NUM> can be further increased.

In the present embodiment, as described above, the motor <NUM> including the motor frame <NUM> provided to the pump casing <NUM> from a side opposite to the suction port 101a in the axial direction is further provided, and the one-sided waterway <NUM> is formed to straddle the motor frame <NUM> and the pump casing <NUM>, and is formed such that the flow path sectional area S2 is gradually decreased from the motor frame <NUM> on the downstream side toward the pump casing <NUM> on the upstream side. Thereby, not only the one-sided waterway <NUM> provided in the pump casing <NUM> but also the one-sided waterway <NUM> provided in the motor frame <NUM> can be formed so that the flow path sectional area S2 is gradually decreased, and therefore, the one-sided waterway <NUM> can be formed over a relatively large range such that the flow path sectional area S2 is gradually decreased. Therefore, a sudden change of the flow path sectional area S2 can be further suppressed, and thus the total head of the submersible pump <NUM> can be further increased.

In the present embodiment, as described above, the impeller <NUM> includes the plate-shaped portion <NUM>, and the blade portion <NUM> provided on the suction port 101a side of the plate-shaped portion <NUM>, and the blade portion <NUM> is formed such that the portion on the inner peripheral side of the blade portion <NUM> is inclined toward the outer peripheral side. Thereby, on the inner peripheral side of the blade portion <NUM>, a larger opening portion on the inner peripheral side where water is first taken into a portion between the blade portions <NUM> via the suction port 101a can be secured by inclining the blade portion <NUM> toward the outer peripheral side. Therefore, the loss on the large flow rate side can be reduced by improving the suction performance, and the lift on the large flow rate side can be increased.

In the present embodiment, as described above, the blade portion <NUM> is formed such that the size D of the blade portion <NUM> in the axial direction is gradually decreased from the inner peripheral side toward the outer peripheral side of the impeller <NUM>, and the facing surface <NUM> of the pump casing <NUM> facing the blade portion <NUM> is inclined from the inner peripheral side toward the outer peripheral side of the impeller <NUM> corresponding to the size D of the blade portion <NUM> in the axial direction, which is gradually decreased, when viewed from a direction orthogonal to the axial direction. Thereby, the loss can be reduced by changing an area ratio between the inlet side and the outlet side in the pump casing <NUM>, and therefore the total head of the submersible pump <NUM> can be further increased.

In the present embodiment, as described above, the impeller <NUM> is formed such that the flow path sectional area S1 of the waterway <NUM> formed between the blade portions <NUM> is gradually decreased from the inner peripheral side toward the outer peripheral side of the impeller <NUM>. Thereby, the outer diameter of the impeller <NUM> can be increased by making the blade width on the outer peripheral side (outlet side) smaller than the blade width on the inner peripheral side (inlet side), and therefore the total head of the submersible pump <NUM> in the small flow rate range can be further increased.

In the present embodiment, as described above, the motor <NUM> including the motor frame <NUM> provided to the pump casing <NUM> from a side opposite to the suction port 101a in the axial direction is further provided, and the inner surface <NUM> of the one-sided waterway <NUM> is formed in a smooth shape without a step between the motor frame <NUM> and the discharge port 101b. Thereby, unlike a case where there is a step, it is possible to prevent the water flow passing through the one-sided waterway <NUM> from being disturbed, and thus the total head of the submersible pump <NUM> can be further increased.

In the present embodiment, as described above, the tongue portion <NUM> extends toward the upstream side of the inlet opening 6a so that the vicinity of the center of the pump chamber 5a is partitioned off from the inlet opening 6a of the one-sided waterway <NUM> when viewed from the axial direction of the rotation shaft <NUM>. Thereby, the connection waterway <NUM> can be arranged to extend in a direction along the water flow generated in the pump chamber 5a by the impeller <NUM> instead of in a direction in which the vicinity of the center of the pump chamber 5a and the inlet opening 6a of the one-sided waterway <NUM> are directly connected. Therefore, water can flow smoothly from the pump chamber 5a to the connection waterway <NUM> at a higher speed, and therefore, the total head of the submersible pump <NUM> can be further increased.

In the present embodiment, as described above, the pump casing <NUM> includes the upper surface 56a that is provided on the other end 10b side of the rotation shaft <NUM> with respect to the connection waterway <NUM>, and forms the connection waterway <NUM>, and the upper surface 56a forming the connection waterway <NUM> connects the tongue portion <NUM> and the inner surface <NUM> of the pump casing <NUM> to each other when viewed from the axial direction of the rotation shaft <NUM>. Thereby, the number of components can be reduced and the device configuration can be simplified as compared with a case where the upper surface that forms the connection waterway by connecting the tongue portion <NUM> and the inner surface <NUM> of the pump casing <NUM> when viewed from the axial direction of the rotation shaft <NUM> is configured by a lid-shaped separate member different from the pump casing.

In the present embodiment, as described above, the motor frame <NUM> is provided with the reduced portion 22c of which the external shape is gradually decreased from the downstream side toward the upstream side along with the flow path sectional area S2 of the one-sided waterway <NUM> being gradually decreased from the motor frame <NUM> on the downstream side toward the pump casing <NUM> on the upstream side. Thereby, the fixing member Fa for the pump casing <NUM> and the motor frame <NUM> can be arranged at a position closer to the one-sided waterway <NUM>, by the space around the reduced portion 22c, which is secured on the pump casing <NUM> side by the reduced portion 22c. Therefore, water leakage from between the pump casing <NUM> and the motor frame <NUM> can be effectively suppressed by firmly fixing the pump casing <NUM> and the motor frame <NUM>.

For example, the length of the tongue portion illustrated in the above embodiment is only an example, the tongue portion may be formed longer than the example illustrated in <FIG>, and the tongue portion may be formed shorter than the example illustrated in <FIG> in a state where the connection waterway is reliably provided.

Further, in the above embodiment, an example is illustrated in which the portion on the inner peripheral side of the blade portion is inclined toward the outer peripheral side, but the present invention is not limited thereto. In the present invention, the portion on the inner peripheral side of the blade portion may be formed to extend downward without being inclined toward the outer peripheral side.

Further, in the above embodiment, an example is illustrated in which the impeller is formed such that the size of the blade portion in the axial direction is gradually decreased from the inner peripheral side toward the outer peripheral side of the impeller, but the present invention is not limited thereto. In the present invention, the impeller may be formed such that the size of the blade portion in the axial direction is constant.

Further, in the above embodiment, an example is illustrated in which the facing surface of the pump casing facing the blade portion is inclined when viewed from a direction orthogonal to the axial direction, but the present invention is not limited thereto. In the present invention, the facing surface may be formed to extend in the horizontal direction.

Further, in the above embodiment, an example is illustrated in which the impeller is formed such that the flow path sectional area of the waterway formed between the blade portions is gradually decreased from the inner peripheral side toward the outer peripheral side of the impeller, but the present invention is not limited thereto. In the present invention, the impeller may be formed such that the flow path sectional area of the waterway formed between the blade portions has a constant size without being changed from the inner peripheral side toward the outer peripheral side of the impeller.

Claim 1:
A submersible pump (<NUM>) in which a one-sided waterway (<NUM>) extending along a rotation shaft (<NUM>) is provided on one side of a submersible pump main body (100a), the submersible pump (<NUM>) comprising:
an impeller (<NUM>) attached to one end (10a) of the rotation shaft (<NUM>); and
a pump casing (<NUM>) in which the impeller (<NUM>) is arranged,
wherein the pump casing (<NUM>) includes
a tongue portion (<NUM>) that is arranged between a pump chamber (5a) in which the impeller (<NUM>) is arranged and an inlet opening (6a) of the one-sided waterway (<NUM>) when viewed from an axial direction of the rotation shaft (<NUM>), and
a connection waterway (<NUM>) that is provided between the tongue portion (<NUM>) and an inner surface (<NUM>) of the pump casing (<NUM>), and is directly connected to the inlet opening (6a) of the one-sided waterway (<NUM>) from an upstream side when viewed from the axial direction of the rotation shaft (<NUM>), and
wherein the submersible pump (<NUM>) further comprises a motor (<NUM>) including a motor frame (<NUM>) provided to the pump casing (<NUM>) from a side opposite to a suction port (101a) in the axial direction, wherein the one-sided waterway (<NUM>) is formed to straddle the motor frame (<NUM>) and the pump casing (<NUM>),
characterized in that
the one-sided waterway (<NUM>) is formed such that a flow path sectional area is gradually decreased from a downstream side toward the inlet opening (6a) on the upstream side, and
the one-sided waterway (<NUM>) is formed such that the flow path sectional area is gradually decreased from the motor frame (<NUM>) on the downstream side toward the pump casing (<NUM>) on the upstream side.