CN108591052B

CN108591052B - Pump impeller

Info

Publication number: CN108591052B
Application number: CN201810184056.5A
Authority: CN
Inventors: 塚本浩司
Original assignee: Nok Corp
Current assignee: Nok Corp
Priority date: 2017-03-07
Filing date: 2018-03-06
Publication date: 2020-10-30
Anticipated expiration: 2038-03-06
Also published as: CN108591052A; US20180258932A1; JP6890439B2; JP2018145901A

Abstract

The problem of the present invention is solved by a pump impeller (1) that does not increase the diameter of the impeller, does not increase the manufacturing cost of the impeller, and increases the reaction force generated by a blade portion by increasing the interference when the impeller is attached to a housing, thereby preventing the blade portion from separating from the inner circumferential surface of the housing and enhancing the discharge performance, the pump impeller comprising: a cylindrical bush (13) rotatably held at an eccentric position inside a cylindrical pump housing via a rotating shaft (3); and a plurality of blade sections (11) that are fixed to the outer peripheral surface of the liner (13), extend in a radial direction, and divide the interior of the pump housing into a plurality of sections (14), wherein each of the blade sections (11) is formed of a rubbery elastic material, and is formed so as to be inclined toward the rotational direction side of the liner (13) with respect to the radial direction from the rotational axis (3) of the liner (13).

Description

Pump impeller

Technical Field

The present invention relates to a pump impeller used for a cooling water pump, a bilge pump, and the like of an outboard engine, and more particularly, to a pump impeller capable of preventing blade portions from separating from an inner peripheral surface of a pump housing and enhancing discharge performance.

Background

Conventionally, as a pump impeller usable for a cooling water pump, a bilge pump, and the like of an outboard engine, a pump impeller having a structure shown in fig. 4 is known (patent documents 1 and 2).

In fig. 4, reference numeral 100 denotes a pump impeller rotatably held in a pump housing 200. The pump impeller 100 is attached to a rotary shaft 300 disposed at an eccentric position in the pump housing 200. The pump impeller 100 includes a plurality of blade portions 110 made of a rubbery elastic material, and is in elastic contact with an inner circumferential surface 210 of the pump housing 200.

The pump impeller 100 divides the interior of the pump casing 200 into a plurality of sections 120 by a plurality of blade portions 110. When the pump impeller 100 rotates via the rotation shaft 300, each blade 110 is bent in a direction opposite to the rotation direction (arrow R) of the pump impeller 100. When the pump impeller 100 rotates, the partition 120 between the adjacent two

blade portions

110, 110 has a reduced volume on the side of the rotary shaft 300 closer to the inner circumferential surface 210 of the pump casing 200, and has an increased volume on the side of the rotary shaft 300 farther from the inner circumferential surface 210 of the pump casing 200.

When the volume of the partition 120 is increased (in the direction of the arrow R1), water is sucked into the partition 120 from the outside through a suction port (not shown) provided in the pump housing 200. When the volume of the partition 120 gradually decreases (in the direction of the arrow R2), water is discharged from the partition 120 to the outside through a discharge port (not shown) provided in the pump housing 200.

In the pump impeller 100 described in patent document 1, each blade 110 is formed to be inclined in a direction opposite to a rotation direction of the impeller 100 with respect to a radial direction.

Such inclination reduces the amount of displacement (interference) of each blade 110 from the natural state when the blade is bent by the rotation of the pump impeller 100, and reduces material fatigue due to the displacement.

Documents of the prior art

Patent document

Patent document 1: japanese Kokai publication Sho 63-010281

Patent document 2: japanese laid-open patent publication No. 2015-074994

However, in recent years, it has been desired to enhance the discharge performance in the above-described pump impeller. In order to enhance the discharge performance, it is necessary to increase the reaction force generated by the blade 110, increase the pressing force against the inner circumferential surface 210 of the pump housing 200, and prevent the blade 110 from being separated from the inner circumferential surface 210 by the water pressure generated during rotation.

As conventional methods for increasing the reaction force generated by the vane portion 110 in the pump impeller 100, increasing the rubber hardness of the vane portion 110, increasing the thickness of the vane portion 110, or increasing the length of the vane portion 110 has been cited.

The rubber hardness of the blade portion 110 is not preferably set to 70 or more in shore a hardness Hs (JIS K6253) at most in order to ensure good tensile properties and fatigue properties. Therefore, in order to increase the reaction force generated by the blade 110, the rubber hardness of the blade 110 cannot be increased.

If the thickness of the blade 110 is increased, the partition 120 between the blade 110 and the blade 110 is narrowed, and thus the suction amount and the discharge amount are reduced. Therefore, the thickness of the blade 110 cannot be increased to increase the reaction force generated by the blade 110.

If the length of the vane portion 110 is increased, the diameter of the pump impeller 100 is increased, and the number of impellers that can be manufactured by one rubber mold is reduced, which causes an increase in manufacturing cost. Therefore, the length of the blade 110 cannot be increased in order to increase the reaction force generated by the blade 110.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide an impeller for a pump, which can prevent a vane portion from being separated from an inner circumferential surface of a casing and enhance discharge performance by increasing a reaction force generated by the vane portion by increasing an effective interference when the impeller is attached to the casing without increasing a diameter of the impeller and without increasing a manufacturing cost of the impeller.

Other problems of the present invention will become apparent from the following description.

The above problems are solved by the following inventions.

In order to solve at least one of the above problems, an impeller for a pump reflecting an aspect of the present invention includes:

a cylindrical bush rotatably held at an eccentric position inside a cylindrical pump housing via a rotating shaft; and a plurality of blade portions fixed to an outer circumferential surface of the liner to radially extend to divide an interior of the pump housing into a plurality of sections,

the plurality of blade portions are each formed of a rubbery elastic material and are formed to be inclined toward the rotational direction side of the bushing with respect to a radial direction from the rotational axis of the bushing.

According to the present invention, it is possible to provide a pump impeller in which the diameter of the impeller is not increased, the manufacturing cost of the impeller is not increased, and the reaction force generated by the vane portion is increased by increasing the effective interference when the impeller is attached to the casing, so that the vane portion is prevented from being separated from the inner circumferential surface of the casing, and the discharge performance can be enhanced.

Drawings

Fig. 1 is a schematic cross-sectional view showing an embodiment of a pump impeller according to the present invention.

Fig. 2 is a schematic view illustrating a structure of inclination of blade portions of the impeller for a pump shown in fig. 1.

Fig. 3 is an enlarged view of a main portion of the pump impeller shown in fig. 2.

Fig. 4 is a plan view showing a conventional pump impeller.

Description of the symbols

Impeller for 1 pump

11 blade part

11a front end side

11b base end side

11c intermediate section

12 front end part

13 liner

14 division

2 Pump case

21 inner peripheral surface

3 rotating shaft

Detailed Description

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

The pump impeller of the present invention is used for a cooling water pump, a bilge pump, and the like of an outboard engine.

Fig. 1 is a schematic cross-sectional view showing an embodiment of a pump impeller according to the present invention, fig. 2 is a schematic view illustrating an inclined structure of blade portions of the pump impeller shown in fig. 1, and fig. 3 is an enlarged view of a main portion of the pump impeller shown in fig. 2.

In fig. 1, reference numeral 1 denotes a pump impeller, and the pump impeller 1 is rotatably held inside a pump housing 2.

The pump housing 2 is formed of a metal material or the like, and has a cylindrical shape with closed upper and lower ends, and has, for example, an unillustrated suction port on the lower surface side and an unillustrated discharge port on the upper surface side. The material of the pump housing 2 is preferably selected to have excellent corrosion resistance when it comes into contact with highly corrosive water.

As shown in fig. 1 to 3, the pump impeller 1 includes a cylindrical hub 13 and a plurality of vane portions 11 radially formed on an outer peripheral surface of the hub 13. In this embodiment, the pump impeller 1 has six blade portions 11.

As shown in fig. 2 and 3, each blade 11 is inclined in the rotation direction (the direction indicated by the arrow R) of the pump impeller 1 in a natural state before being mounted on the casing. The method of inclining is not particularly limited, but inclining is performed by a molding method in the present embodiment. The details of the tilt structure will be described later.

In the embodiment shown in fig. 1, the impeller 1 rotates, and the blade portions 11 are bent in the direction opposite to the rotation direction R of the impeller 1 by sliding contact with the inner circumferential surface 21 of the pump housing 2. The impeller 1 rotates at a rotational speed of, for example, about 6000 revolutions per minute.

The bush 13 is formed of a resin material such as a thermoplastic resin or a thermosetting resin. The material of the bush 13 is not particularly limited, but for example, a polyamide resin having excellent strength can be selected and used.

Each blade 11 is made of a rubbery elastic material such as Chloroprene Rubber (CR) or nitrile rubber (NBR), and is bonded to the outer circumferential surface of bushing 13. The bonding method is not particularly limited, but the blade 11 may be sintered on the bush 13 after applying an adhesive to the bush 13 to mold it, or may be bonded to the bush 13 by an adhesive after molding the blade 11.

For the rubber hardness of each blade 11, in order to ensure good tensile properties and fatigue properties, a rubber having a shore a hardness Hs (JIS K6253) in the range of 45 to 75 may be used. As described later, since the blade 11 is inclined in the rotation direction, a rubber having good fatigue characteristics and low hardness can be selected for the rubber hardness. However, the rubber having a rubber hardness of less than 45 is not used because the rubber reaction force is too low.

The bush 13 is attached to the rotary shaft 3 disposed at an eccentric position in the pump housing 2, and is rotatably held by the rotary shaft 3.

The bush 13 has a shaft hole 13a along the central axis, and the rotary shaft 3 is inserted into the shaft hole 13 a. A key groove 13b is provided on the inner peripheral surface of the shaft hole 13 a. Parallel keys 3a formed on the outer peripheral surface of the rotary shaft 3 are fitted into the key grooves 13b so that the rotary shaft 3 does not run idle.

The bush 13 is driven to rotate along with the blade portions 11 by a power source not shown through the rotary shaft 3.

The tip portions 12 of the blade portions 11 elastically contact the inner circumferential surface 21 of the pump housing 2.

The blade 11 may be provided with a sliding contact member made of a resin material at the tip 12, and the sliding contact member may be elastically brought into contact with the inner circumferential surface 21 of the pump housing 2. The sliding contact member may cover the tip end portion 12 of the blade 11. The sliding contact member is preferably formed of a fluorine-containing resin, a polyamide resin, or the like, which is excellent in sliding resistance and the like. In this case, the sliding resistance can be stably reduced for a long period of time, the pump impeller 1 can be prevented from being worn or damaged, and the rotation torque can be reduced, the power loss can be reduced, and the fuel consumption can be improved.

As shown in fig. 1, the pump impeller 1 divides the interior of the pump casing 2 into a plurality of sections 14 by a plurality of blade portions 11. When the pump impeller 1 rotates via the rotary shaft 3 and the bush 13, the vane portions 11 are bent in a direction opposite to the rotation direction of the impeller 1 (the direction indicated by the arrow R in fig. 1).

At this time, the blade portions 11 press the inner circumferential surface 21 of the pump housing 2 with the tip end sides 11a including the tip end portions 12, thereby generating a reaction force (restoring force). The tip end side 11a of the vane 11 is pressed against the inner circumferential surface 21 of the pump housing 2 by the reaction force (restoring force).

In the pump impeller 1, the blade portions 11 are pressed against the inner circumferential surface 21 of the pump housing 2 with a large force, and therefore, the blade portions 11 can be prevented from being separated from the inner circumferential surface 21 by the water pressure generated during rotation.

When the pump impeller 1 rotates, the respective segments 14 between the two

vane portions

11 and 11 reduce the volume of the segments 14 on the side of the rotary shaft 3 closer to the inner circumferential surface 21 of the pump casing 2 (the left side in fig. 1), thereby increasing the pressure in the segments 14, and expand the volume of the segments 14 on the side of the rotary shaft 3 farther from the inner circumferential surface 21 of the pump casing 2 (the right side in fig. 2), thereby reducing the pressure in the segments 14.

In a section (a section indicated by an arrow R1) in which the volume of the partition 14 gradually increases, water is sucked into the partition 14 from the outside through a suction port (not shown). In a section (a section indicated by an arrow R2) in which the volume of the partition 14 gradually decreases, water is discharged from the partition 14 to the outside through a discharge port (not shown).

Next, the tilting structure of the blade portion will be specifically described based on fig. 2 and 3.

As shown in these drawings, each blade portion 11 of the pump impeller 1 is formed in the following shape: the angle θ is inclined toward the rotation direction R of the bush 13 with respect to the radial direction of the central axis 3c of the rotation shaft 3 of the self-holding bush 13.

Since each blade 11 is formed to be inclined at an angle θ toward the rotation direction R of the liner 13, as shown in fig. 1, when the pump impeller 1 rotates, the front end side (lip) 11a is bent in the reverse rotation direction starting from the intermediate portion 11c, and the pressing force F against the inner circumferential surface 21 of the pump housing 2 increases, that is, the interference increases.

The pressing force F acts to restore the distal end side 11a of the blade 11.

Then, the pressing force F against the inner peripheral surface 21 of the pump casing increases, and a pressing force F (reaction force) for restoring the distal end side 11a acts on the intermediate portion 11 c.

As a result, the base end side 11b is prevented from being bent in the reverse rotation direction, and the state of being inclined in the rotation direction R is maintained.

That is, as the pressing force F increases, the base end side 11b of the blade 11 can be kept inclined in the rotation direction R as a result.

When the impeller 1 rotates in the pump casing 2, the interference between the vane portions 11 increases, and therefore the reaction force generated by the vane portions 11 increases.

Since the blade portions 11 are prevented from separating from the inner peripheral surface 21 by increasing the pressing force against the inner peripheral surface 21 of the pump housing 2, water does not leak to other portions in the respective sections 14 of the pump housing 2 partitioned by the blade portions 11. Further, since water does not leak out to other sections in each section 14, the discharge performance can be enhanced as a result.

In the impeller 1, the pressing force F on the inner peripheral surface 21 can be increased even when the blade portions 11 are provided to have a thickness slightly smaller than that of the conventional impeller by inclining the blade portions 11 in the rotation direction R. As a result, the area 14 between the two

blade sections

11, 11 can be made larger, and the suction amount and the discharge amount can be increased.

Further, in the pump impeller 1, the blade portions 11 are inclined according to the specific inclination structure of the present invention, so that the diameter does not increase as compared with the conventional impeller. As a result, the number of products that can be manufactured by one rubber mold is not reduced, and the manufacturing cost is not increased.

As shown in fig. 3, the length L2 of the blade 11 is longer than the length L1 (the length of the blade 11 that always slides against the inner circumferential surface 21 of the pump housing 2 and bends) required when the blade 11 is not tilted by the tilt angle θ.

If the angle of inclination θ of the blade 11 is small, the length L2 of the blade 11 is close to the length L1, and the length L2 of the blade 11 is greater than the length L1 for larger angles of inclination θ.

If the inclination angle θ of the blade 11 is too small, the interference does not increase sufficiently when the impeller 1 in the housing 2 rotates, and the required reaction force cannot be generated. In contrast, if the inclination angle θ of the blade 11 is too large, the impeller 1 may not be bent when rotating.

Accordingly, the preferred inclination angle θ of the blade 11 is about 0.1 to 10 degrees. The inclination angle θ may be an angle that can maintain the base end side 11b inclined in the rotation direction R in the above-described relationship with the pressing force F during rotation.

The thickness T of the vane portion 11 can be set as appropriate in accordance with the relationship with the inner diameter of the pump housing 2. The inclination angle θ and the thickness T of the blade 11 are preferably designed to be able to maintain the state in which the base end side 11b is inclined in the rotation direction R during rotation.

By satisfying these conditions, each blade 11 can be bent well when the pump impeller 1 rotates, the interference is sufficiently increased, and a required reaction force is generated, and as a result, the discharge performance can be enhanced.

The present invention is not limited to the above-described embodiments, and various configurations may be adopted without departing from the gist of the present invention.

Claims

1. An impeller for a pump, comprising: a cylindrical bush rotatably held at an eccentric position inside a cylindrical pump housing via a rotating shaft; and a plurality of blade portions fixed to an outer peripheral surface of the liner and extending radially to divide an interior of the pump housing into a plurality of sections,

the plurality of blade portions are each formed of a rubbery elastic material and are formed to be inclined toward a rotation direction side of the bushing with respect to a radial direction from a rotation axis of the bushing,

the plurality of blade portions each have a base end side fixed to one side of the outer peripheral surface of the liner and a tip end side in sliding contact with the inner peripheral surface of the pump housing,

the plurality of blade portions are formed as follows: even if the tip end side of the blade portion is pressed and bent in the reverse rotation direction, the base end side is kept in a state of being inclined in the rotation direction.

2. Impeller for a pump according to claim 1,

the plurality of blade portions extend from a base end side located on a side fixed to an outer peripheral surface of the liner to a tip end side in sliding contact with an inner peripheral surface of the pump housing,

the base end sides of the blade portions are formed to be inclined toward the rotational direction side of the bushing with respect to the radial direction from the rotational axis of the bushing.

3. Impeller for a pump according to claim 2,

the blade portion is formed to incline toward the rotation direction side of the bushing with respect to a radial direction from the rotation axis of the bushing from the base end side to the tip end side of the blade portion.