IMPELLER AND PUMP

Abstract

The present application relates an impeller and a pump. The impeller includes a shaft insertion hole, a fastening hole having a diameter smaller than a diameter of the shaft insertion hole, and a sleeve insertion hole having a diameter larger than a diameter of the shaft insertion hole.

Description

TECHNICAL FIELD

The present invention relates to an impeller and a pump.

BACKGROUND ART

A pump is known to transport a liquid by rotating an impeller fixed to a main shaft of an electric motor. The pump has a seal structure to prevent the liquid from contacting the main shaft.

CITATION LIST

Patent Literature

• • Patent document 1: Japanese laid-open utility model publication No. S53-88803
  • Patent document 2: Japanese laid-open utility model publication No. S60-88098

SUMMARY OF INVENTION

Technical Problem

The patent document 1 (Japanese laid-open utility model publication No. S53-88803) discloses an impeller (2) fastened to a main shaft (10) by a bolt (4). The impeller (2) has a boss portion (22) covering a portion of the main shaft (10), and the boss portion (22) and an exposed portion of the main shaft (10) are covered by a sleeve (5). In this manner, the pump (1) of the patent document 1 prevents the liquid from contacting the main shaft (10).

However, in a configuration of the patent document 1, the pump (1) includes an O ring (31) and a lock ring (40) to close a gap between the impeller (2) and the bolt (4), and further includes an O ring (7) arranged between the boss portion (22) and the sleeve (5).

Thus, in the configuration of the patent document 1, it is necessary to arrange three seal members, but from a viewpoint of improving pump reliability, it is desirable to reduce the number of seal members by arranging the seal member that can reliably prevent the liquid from coming into contact with the main shaft.

Therefore, the present invention provides an impeller and a pump that can improve reliability.

Solution to Problem

In an embodiment, there is provided an impeller, comprising: a shaft insertion hole into which a main shaft of an electric motor can be inserted; a fastening hole having a diameter smaller than a diameter of the shaft insertion hole, and into which a fastener fastened to the main shaft can be inserted; and a sleeve insertion hole having a diameter larger than a diameter of the shaft insertion hole, and into which a shaft sleeve attached to the main shaft can be inserted, the sleeve insertion hole has a seal groove formed on an opposite surface of the shaft sleeve when the shaft sleeve is inserted into the sleeve insertion hole.

In an embodiment, the impeller comprises a main plate having a machined surface that is connected to the fastening hole and forms a front surface of the impeller.

In an embodiment, the fastening hole, the shaft insertion hole, and the sleeve insertion hole are arranged in this order, in a straight line.

In an embodiment, there is provided a pump comprising: an impeller, a fastener, and a shaft sleeve above described; a seal washer configured to close a gap between a head portion of the fastener and the fastening hole; and a seal member attached to the seal groove and configured to close a gap between the sleeve insertion hole and the shaft sleeve.

In an embodiment, the seal washer, the impeller, and the shaft sleeve are arranged in this order, in a straight line, and the fastener is configured to press a metal portion of the seal washer, the metal impeller, and the metal shaft sleeve against a step portion of the main shaft by a fastening force of the fastener.

In an embodiment, the shaft sleeve has a non-rotating groove that can fit a key formed on an inner surface of the shaft insertion hole.

Advantageous Effects of Invention

The impeller includes a sleeve insertion hole having a seal groove formed on an opposite surface of a shaft sleeve. Therefore, a seal member arranged between the shaft sleeve inserted into the sleeve insertion hole and the sleeve insertion hole can reliably prevent the liquid from contacting the main shaft. As a result, the pump can improve its reliability.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view showing a pump apparatus;

FIG. 2 is an enlarged view of an impeller;

FIG. 3 is a view showing a seal washer;

FIG. 4 is a partially enlarged view of FIG. 1;

FIG. 5A is a view showing a key formed in a shaft insertion hole;

FIG. 5B is a view showing a key groove formed in a main shaft; and

FIG. 6 is a view showing a non-rotating groove formed in the shaft sleeve.

DESCRIPTION OF EMBODIMENTS

Embodiments of a pump apparatus are described below with reference to the drawings. In the following embodiments, identical or equivalent components will be marked with the same symbol and redundant explanations will be omitted.

FIG. 1 is a view showing a pump apparatus. As shown in FIG. 1, the pump apparatus PA includes a pump P that transports a liquid, and an electric motor M that operates the pump P. The pump P includes an impeller 2 fixed to a main shaft 1 of the electric motor M and a pump casing 10 that accommodates the impeller 2.

The impeller 2 is fixed to the main shaft 1 by a fastener 6. The impeller 2 includes a main plate 3 having a disk shape, a side plate 4 having a liquid inlet, and a plurality of vanes 5 arranged between the main plate 3 and the side plate 4. The fastener 6 is a part of components of the pump P.

The pump casing 10 has a suction port 11 and a discharge port 12. By driving the electric motor M, the impeller 2 in the pump casing 10 rotates, and the liquid is sucked into the pump casing 10 through the suction port 11. The liquid sucked into the pump casing 10 is discharged to an outside through the discharge port 12.

The pump P includes a shaft sleeve 15 attached to the main shaft 1, and a mechanical seal 16 attached to the shaft sleeve 15. The mechanical seal 16 is arranged between the impeller 2 and the pump casing 10, and is configured to prevent the liquid from leaking to the electric motor M side.

FIG. 2 is an enlarged view of the impeller. As shown in FIG. 2, the main plate 3 has a shaft insertion hole 50 formed in its center and into which the main shaft 1 of the electric motor M can be inserted, a fastening hole 51 communicating with the shaft insertion hole 50 and into which the fastener 6 can be inserted, and a sleeve insertion hole 52 communicating with the shaft insertion hole 50 and into which the shaft sleeve 15 can be inserted.

The fastening hole 51, the shaft insertion hole 50, and the sleeve insertion hole 52 are arranged in a straight line along a direction of an axis CL of the main shaft 1 in this order. Therefore, when an operator fastens the fastener 6 while inserting the main shaft 1 with the shaft sleeve 15 into the shaft insertion hole 50, the impeller 2 is fixed to the main shaft 1, and the shaft sleeve 15 is inserted into the sleeve insertion hole 52.

As shown in FIG. 2, the sleeve insertion hole 52 has an annular seal groove 36 formed on an opposite surface (i.e., an inner surface of the sleeve insertion hole 52) of the shaft sleeve 15 when the shaft sleeve 15 is inserted into the sleeve insertion hole 52. The pump P includes a seal member 35 mounted in the seal groove 36. The seal member 35 is, for example, an O ring, and closes a gap between the sleeve insertion hole 52 and the shaft sleeve 15.

The fastening hole 51 has a diameter D2 smaller than a diameter D1 of the shaft insertion hole 50 (D2<D1), and the sleeve insertion hole 52 has a diameter D3 larger than the diameter D1 of the shaft insertion hole 50 (D3>D1). Thus, by forming the sleeve insertion hole 52 having the diameter D3 larger than the diameter D1 of the shaft insertion hole 50, the seal member 35 can be arranged between the main plate 3 and the shaft sleeve 15.

According to the embodiment, the seal member 35 can reliably prevent the liquid from contacting the main shaft 1, thus improving the reliability of the pump P. A carbon steel (e.g., S45C) may be used as a material of the main shaft 1. The carbon steel may corrode due to contact with the liquid. If the main shaft 1 corrodes, the main shaft Imust be replaced. The pump P can reliably prevent the liquid from contacting the main shaft 1, thus reliably preventing corrosion of the main shaft 1.

FIG. 3 is a view showing a seal washer. As shown in FIGS. 2 and 3, the pump P includes a seal washer 30 that closes a gap between a head portion 6a of the fastener 6 and the fastening hole 51. The seal washer 30 has an annular metal ring 31 and a rubber ring 32 arranged radially inward of the metal ring 31. By fastening the fastener 6, the rubber ring 32 of the seal washer 30 is pressed against the main plate 3 by the head portion 6a of the fastener 6 to close the gap between the head portion 6a and the fastening hole 51. By arranging the seal washer 30, it is possible to prevent the liquid from entering the fastening hole 51. As a result, the seal washer 30 can reliably prevent the liquid from coming into contact with the main shaft 1.

As described above, the configuration of the patent document 1 requires the arrangement of three seal members, but in this embodiment, by arranging two seal members (i.e., seal member 35 and seal washer 30), the pump P can prevent the liquid from contacting the main shaft 1. As a result, an overall cost of the pump P can be reduced. Furthermore, by reducing the number of seal members, a service life and maintainability of the pump P can be improved.

As shown in FIG. 2, the main plate 3 of the impeller 2 preferably has a machined surface 40 that is connected to the fastening hole 51 and forms a front surface of the impeller 2. The machined surface 40 is a flat surface for improving an adhesion of the seal washer 30 to the main plate 3. The seal washer 30 arranged between the head portion 6a of the fastener 6 and the machined surface 40 can more reliably close the gap between the head portion 6a and the fastening hole 51.

FIG. 4 is a partially enlarged view of FIG. 1. As shown in FIG. 4, the seal washer 30, the impeller 2, and the shaft sleeve 15 are arranged in this order in a straight line along the direction of the axis CL. The shaft sleeve 15 is arranged between the main plate 3 of the impeller 2 and a step portion 1a of the main shaft 1, and a movement of the shaft sleeve 15 in the direction of the axis CL is restricted.

Each of the impeller 2 and the shaft sleeve 15 is made of a metal, and the seal washer 30 includes the metal ring 31. Therefore, the fastener 6 can press a metal portion (i.e., metal ring 31) of the seal washer 30, the impeller 2, and the shaft sleeve 15 against the step portion 1a of the main shaft 1 by a fastening force of the fastener 6. The fastener 6 can transmit its fastening force to the step portion 1a of the main shaft 1 through a contact of a metal member (i.e., seal washer 30, impeller 2, and shaft sleeve 15) of the pump P. Therefore, the fastener 6 can fully exert its fastening force, and reliably prevent the components of the pump P from loosening or falling off.

FIG. 5A is a view showing a key formed in the shaft insertion hole, and FIG. 5B is a view showing a key groove formed in the main shaft. The main plate 3 has a key 55 (see FIG. 5A) formed on an inner surface of the shaft insertion hole 50. The main shaft 1 has a key groove 20 formed on an outer surface of the main shaft 1 (see FIG. 5B). The key groove 20 is formed by performing an electrical discharge machining on the main shaft 1.

These key 55 and key groove 20 extend in the direction of the axis CL, and by inserting the main shaft 1 into the shaft insertion hole 50, and the key 55 fits into the key groove 20. By fitting the key 55 into the key groove 20, the main shaft 1 can reliably transmit a torque to the impeller 2.

FIG. 6 is a view showing a non-rotating groove formed in the shaft sleeve. As shown in FIG. 6, the shaft sleeve 15 has a non-rotating groove 25 connected to an end surface 15a of the shaft sleeve 15. The non-rotating groove 25 extends in the direction of the axis CL, and can fit into the key 55 formed on the inner surface of the shaft insertion hole 50. By moving the non-rotating groove 25 in a direction of an arrow in FIG. 6, the non-rotating groove 25 fits into the key 55. This configuration restricts the movement of the shaft sleeve 15 in the direction of rotation.

The above embodiments are described for the purpose of practicing the present invention by a person with ordinary skill in the art to which the invention pertains. Although preferred embodiments have been described in detail above, it should be understood that the present invention is not limited to the illustrated embodiments, but many changes and modifications can be made therein without departing from the appended claims.

INDUSTRIAL APPLICABILITY

The present invention is applicable to an impeller and a pump.

REFERENCE SIGNS LIST

• • 1 main shaft
  • 1 a step portion
  • 2 impeller
  • 3 main plate
  • 4 side plate
  • 5 vane
  • 6 fastener
  • 6 a head portion
  • 10 pump casing
  • 11 suction port
  • 12 discharge port
  • 15 shaft sleeve
  • 15 a end surface
  • 16 mechanical seal
  • 20 key groove
  • 25 non-rotating groove
  • 30 seal washer
  • 31 metal ring
  • 32 rubber ring
  • 5.35 seal member
  • 36 seal groove
  • 40 machined surface
  • 50 shaft insertion hole
  • 51 fastening hole
  • 52 sleeve insertion hole
  • 55 key

Claims

1. An impeller, comprising: a shaft insertion hole into which a main shaft of an electric motor can be inserted;a fastening hole having a diameter smaller than a diameter of the shaft insertion hole, and into which a fastener fastened to the main shaft can be inserted; anda sleeve insertion hole having a diameter larger than a diameter of the shaft insertion hole, and into which a shaft sleeve attached to the main shaft can be inserted,wherein the sleeve insertion hole has a seal groove formed on an opposite surface of the shaft sleeve when the shaft sleeve is inserted into the sleeve insertion hole, andwherein the shaft sleeve is arranged in a straight line between a main plate of the impeller and a step portion of the main shaft, and the fastener is fastened to apply a fastening force to an entire shaft sleeve.

2. The impeller according to claim 1, wherein the impeller comprises a main plate having a machined surface that is connected to the fastening hole and forms a front surface of the impeller.

3. The impeller according to claim 1, wherein the fastening hole, the shaft insertion hole, and the sleeve insertion hole are arranged in this order, in a straight line.

4. A pump comprising: an impeller, a fastener, and a shaft sleeve according to claim 1;a seal washer configured to close a gap between a head portion of the fastener and the fastening hole; anda seal member attached to the seal groove and configured to close a gap between the sleeve insertion hole and the shaft sleeve.

5. The pump according to claim 4, wherein the seal washer, the impeller, and the shaft sleeve are arranged in this order, in a straight line, and wherein the fastener is configured to press a metal portion of the seal washer, the metal impeller, and the metal shaft sleeve against a step portion of the main shaft by a fastening force of the fastener.

6. The pump according to claim 4, wherein the shaft sleeve has a non-rotating groove that can fit a key formed on an inner surface of the shaft insertion hole.

7. The impeller according to claim 1, wherein the shaft sleeve has an impeller side end portion that can be inserted into the sleeve insertion hole and an anti-impeller side end portion that can be pressed against the step portion of the main shaft and is aligned with the impeller side end portion, and wherein the impeller side end portion is inserted into the sleeve insertion hole, and the anti-impeller side end portion is pressed against the step portion, and the fastener is fastened to apply the fastening force to the entire shaft sleeve.