Impeller for pump

Abstract

Provided is an impeller for a pump, for which it is possible to easily ascertain the degree of wear of a blade wheel (impeller). An impeller 10 for a pump is formed of at least a primary member 100 and a secondary member configured to cover the primary member 100. The primary member 100 includes a substantially disk-shaped plate section 110, and a blade section 120 formed on one surface side of the plate section 110 so as to correspond to a blade 12 of the impeller 10 for a pump. The primary member 100 and the secondary member are made of different resin materials.

Description

Pump impeller

[0001] The present invention relates to an impeller for a pump.

[0002] BACKGROUND ART Impellers used in submersible pumps are conventionally known.

[0003] For example, Patent Document 1 discloses a technology related to an impeller that prevents deformation of rubber or resin blades due to pressure from a fluid when the impeller rotates. Specifically, the impeller is configured by embedding metal reinforcing members inside the plate-like portion and the blades.

[0004] JP 2017-210937 A

[0005] However, even with the impeller disclosed in Patent Document 1, wear is unavoidable due to contaminants such as sand contained in the fluid that hits the impeller (particularly the blade portion) when the impeller rotates.

[0006] For example, if the blades of the impeller wear to the point where they can no longer perform their intended function, there is a concern that this will lead to a decline in pump performance, and it is desirable to inspect and replace the impeller before such a situation occurs.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a pump impeller that allows the degree of wear of the impeller to be easily determined.

[0008] A pump impeller according to one aspect of the present invention is a pump impeller used in an underwater pump, and is formed of at least a primary member and a secondary member configured to cover the primary member, the primary member including a roughly disk-shaped plate portion and a blade portion formed on one side of the plate portion to correspond to the blades of the pump impeller, and the primary member and secondary member are made of different resin materials.

[0009] In the above aspect, among the blades of the pump impeller, at least a portion of the vane portion formed by the primary member and at least a portion formed by the secondary member so as to cover the vane portion may be configured in different colors.

[0010] In the above aspect, at least a portion of the blades of the pump impeller that is formed of a secondary member so as to cover the vane portion may be transparent.

[0011] In the above aspect, the wing portion may include a marking portion having a first height on at least a portion of the wing portion.

[0012] In the above aspect, the secondary member may be configured to cover, with approximately the same thickness, a side wall portion of the marker portion on the rotation direction side of the pump impeller and a side wall portion on the opposite side to the rotation direction.

[0013] In the above aspect, the secondary member may be configured to cover a side wall portion of the marker portion on a rotation direction side of the pump impeller with a thickness greater than that of a side wall portion on an opposite side to the rotation direction.

[0014] In the above aspect, the secondary member may be configured to cover the tip portion of the sign portion with a thickness greater than that of one surface side of the plate-shaped portion.

[0015] In the above aspect, the blade portion may include a rib portion having a second height smaller than the first height of the blade portion.

[0016] In the above aspect, the primary member may be made of a resin material, and the secondary member may be made of a resin material that is softer than the primary member.

[0017] According to the present invention, it is possible to provide a pump impeller that allows the degree of wear of the impeller to be easily determined.

[0018] 1 is a perspective view showing the appearance of a pump impeller 10 according to one embodiment of the present invention. FIG. 2 is a perspective view showing the appearance of a primary member 100 constituting the pump impeller 10 according to one embodiment of the present invention. FIG. 3 is a perspective view showing the primary member 100 arranged inside the pump impeller 10 according to one embodiment of the present invention. FIG. 4 is an enlarged view of part E shown in FIG. 3 for more specifically explaining the arrangement of the blade portion 120 (marked portion 121) of the primary member 100 inside the blade 12 of the pump impeller 10 according to one embodiment of the present invention. FIG. 5 is a view showing another specific example in which the blade portion 120 (marked portion 121) of the primary member 100 is arranged inside the blade 12 of the pump impeller 10 according to one embodiment of the present invention. FIG. 6 is a perspective view showing the appearance of a primary member 200 constituting the pump impeller 10 according to one embodiment of the present invention. FIG. 7 is a perspective view showing the appearance of a primary member 300 constituting the pump impeller 10 according to one embodiment of the present invention. Fig. 9 is an enlarged view showing details of a blade portion 320 in the primary member 300 shown in Fig. 8. Fig. 10 is a perspective view showing the appearance of a primary member 400 constituting the pump impeller 10 according to one embodiment of the present invention.

[0019] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the embodiment described below is merely a specific example for carrying out the present invention and is not intended to limit the scope of the present invention. Furthermore, to facilitate understanding of the description, the same components in each drawing will be designated by the same reference numerals wherever possible, and duplicate descriptions may be omitted.

[0020] <One embodiment> [Outline of pump impeller] Figure 1 is a perspective view showing the appearance of a pump impeller 10 according to one embodiment of the present invention. As shown in Figure 1, the pump impeller 10 includes a main plate (disk portion) 11 and eight blades 12 on one side of the main plate 11, and is used in a submersible pump. The main plate 11 is formed with a bearing portion 13 having a through hole in which a rotating shaft that rotates the pump impeller 10 is installed.

[0021] The pump impeller 10 is formed of at least a primary member and a secondary member configured to cover the primary member, and it can be seen from the exterior of the pump impeller 10 that a portion of the primary member is exposed.

[0022] In the pump impeller 10, there is an exposed portion 14 where the primary member is exposed between each of the eight blades 12. That is, on one side of the main plate (disk portion) 11 of the pump impeller 10 where the eight blades 12 are arranged, there is an exposed portion 14 of the primary member that is not covered by the secondary member between each of the eight blades 12.

[0023] Furthermore, on the other side of the main plate (disk portion) 11, at a position corresponding to the exposed portion 14 of the primary member on that side, there is an exposed portion of the primary member that is not covered by the secondary member, similar to the exposed portion 14.

[0024] In the bearing portion 13 of the pump impeller 10, the inner wall surface of the through hole in which the rotating shaft is disposed, where the rotating shaft abuts, is not covered with the secondary member, and the primary member is exposed. In other words, when the rotating shaft is disposed in the through hole of the bearing portion 13, the rotating shaft abuts against the primary member.

[0025] [Configuration of Primary Member in Pump Impeller] Figure 2 is a perspective view showing the appearance of primary member 100 constituting pump impeller 10 according to one embodiment of the present invention. As shown in Figure 2, primary member 100 includes plate-shaped portion 110, eight blade portions 120, bearing portion 130, multiple protrusions 140, and multiple through holes 150, and is disposed inside pump impeller 10 as a core member.

[0026] The plate-like portion 110 has a substantially disk shape and is mainly disposed inside the main plate (disk portion) 11 of the pump impeller 10 .

[0027] The eight vane portions 120 are formed on one surface of the plate-like portion 110 so as to be arranged inside the pump impeller 10 corresponding to the eight blades 12. Each of the eight vane portions 120 includes a marking portion 121 and a rib portion 122.

[0028] The sign portion 121 is formed on the outer edge side of the substantially disk-shaped plate portion 110 of the blade portion 120. For example, in this example, the sign portion 121 is formed in a region of the blade portion 120 that is approximately ¼ to ⅓ of the way from the outer edge of the plate portion 110.

[0029] The vane portion 120 is configured inside the blade 12 of the pump impeller 10 by being covered with a secondary member, and is configured so that as the pump impeller 10 is used and the secondary member of the blade 12 gradually wears, the marking portion 121 of the vane portion 120 appears on the surface. In other words, the marking portion 121 serves as an indicator function for understanding the degree of wear of the secondary member of the blade 12. The indicator function will be described in detail later.

[0030] The rib portion 122 is formed in an area of ​​the blade portion 120 other than the marked portion 121. The height (second height) of the rib portion 122 may be smaller than the height (first height) of the marked portion 121. This makes it difficult for the rib portion 122 to appear on the surface even if the secondary member of the blade 12 gradually wears.

[0031] As long as the marking portion 121 of the vane portion 120 is formed to fulfill the indicator function, the shape of the eight vane portions 120 (marking portion 121 and rib portion 122) may be made larger, smaller, thicker, or thinner, taking into consideration the strength required of the eight blades 12 of the pump impeller 10. Furthermore, the shape of the eight vane portions 120 (marking portion 121 and rib portion 122) may also be such that the height protruding from one surface of the plate-like portion 110 is made larger or smaller, and further, the height may be made different between the center side and the outer edge side of the plate-like portion 110.

[0032] The bearing portion 130 has a through-hole formed in the center of the plate-shaped portion 110, through which the rotating shaft passes. The shape of the through-hole may be, for example, circular, or may be a so-called D-cut shape in which at least a portion of the circle is made straight. In other words, if the shape of the through-hole is D-cut, the rotating shaft will also be a D-cut shaft in which a D-cut has been applied accordingly.

[0033] As described above, in the pump impeller 10, the inner wall of the through-hole in which the rotating shaft is disposed, against which the rotating shaft abuts, is not covered by the secondary member, and the primary member 100 is exposed. In other words, when the pump impeller 10 is used, the rotating shaft rotates, and a large torque is transmitted to the primary member 100 that directly abuts against it. In this case, if the through-hole is shaped like a D-cut and a D-cut shaft is used for the rotating shaft, the pump impeller 10 and the rotating shaft can be firmly fastened together, preventing free rotation and reducing wear on the bearing portion 130 of the primary member 100.

[0034] The plurality of protrusions 140 are formed so as to protrude from one surface and the other surface of the plate-shaped portion 110. For example, on one surface of the plate-shaped portion 110, the plurality of protrusions 140 are formed between the eight blade portions 120, two protrusions each in the vicinity of the outer edge of the plate-shaped portion 110 (outer region) and in the intermediate region between the bearing portion 130 and the outer edge of the plate-shaped portion 110, for a total of 16 protrusions 140. On the other surface of the plate-shaped portion 110, the plurality of protrusions 140 are formed at positions corresponding to the positions of the plurality of protrusions 140 formed on the one surface of the plate-shaped portion 110.

[0035] Here, the intermediate region and outer region refer to the intermediate region and outer region of the plate-shaped portion 110 when the distance from the outer periphery of the bearing portion 130 to the outer edge of the plate-shaped portion 110 is divided into thirds to define the inner region (bearing portion 130 side), the intermediate region, and the outer region (outer edge side of the plate-shaped portion 110).

[0036] The 16 protrusions 140 are provided for fixing (aligning) the primary member 100 to a mold for molding the pump impeller 10 when producing the pump impeller 10. Specifically, the primary member 100 serving as a core material for the pump impeller 10 is inserted into a mold for molding the pump impeller 10, and then the secondary member is filled in, thereby producing the pump impeller 10. At this time, the bearing portion 130 of the primary member 100 is fitted into a position in the mold corresponding to the rotation shaft, and the 16 protrusions 140 of the primary member 100 abut against the interior of the mold, thereby fixing the primary member 100 to the mold.

[0037] The plurality of through holes 150 are formed so as to penetrate from one surface side to the other surface side of the plate-shaped portion 110. For example, the plurality of through holes 150 are formed between the eight blade portions 120, one on each side in the outer region of the plate-shaped portion 110, and four near the outer periphery (inner region) of the bearing portion 130, for a total of 12 through holes.

[0038] [Indicator Function] Fig. 3 is a perspective view showing the primary member 100 disposed inside the pump impeller 10 according to one embodiment of the present invention. As shown in Fig. 3, the primary member 100 is disposed inside the pump impeller 10 as a core material of the pump impeller 10.

[0039] The pump impeller 10 rotates in the direction shown in FIG. 3 by the rotation of the rotary shaft disposed in the through hole of the bearing portion 13 .

[0040] As the pump impeller 10 rotates, sand and other contaminants contained in the fluid that hits the pump impeller 10 cause wear to the pump impeller 10. That is, as the secondary member configured to cover the primary member 100 gradually wears away, the primary member 100 begins to appear on the surface.

[0041] 3, a large pressure from the fluid is applied to the blades 12 of the pump impeller 10. In particular, the pressure from the fluid applied to the outer edge of the main plate 11 of the side wall portion of the blades 12 on the rotational direction side is thought to be larger than that of other portions, and sand and other impurities contained in the fluid collide with this portion, causing severe wear of the secondary member in that portion.

[0042] 4 is an enlarged view of part E shown in FIG. 3 for more specifically illustrating the arrangement of the vane portion 120 (marked portion 121) of the primary member 100 inside the blade 12 of the pump impeller 10 according to one embodiment of the present invention. As shown in FIG. 4, the marked portion 121 of the primary member 100 is arranged inside the blade 12 as viewed from the outer edge side of the main plate 11.

[0043] The blade 12 has a vane portion 120 disposed inside, and a marking portion 121 is disposed on the outer edge side of the substantially disk-shaped plate portion 110 of the vane portion 120. As described above, when the pump impeller 10 rotates in the rotational direction, the secondary member of the side wall portion 12A on the rotational direction side of the blade 12 gradually wears away, and the marking portion 121 appears on the surface.

[0044] The primary member 100 and the secondary member are configured to be visually identifiable, so that it can be seen that the secondary member is worn at the side wall portion 12A and the marking portion 121 of the primary member 100 appears on the surface.

[0045] The primary member 100 and the secondary member may be configured in different colors, for example, the primary member 100 may be configured in black and the secondary member may be configured in orange. Also, the colors of each member are not limited to these, and the primary member 100 may be configured in gray or the like and the secondary member may be configured in red or the like.

[0046] The secondary member may be transparent, which allows the primary member 100 (the marking portion 121) disposed inside the secondary member to be confirmed, thereby enabling the extent to which the primary member 100 (the marking portion 121) appears on the surface to be grasped.

[0047] 4, the marked portion 121 is disposed in the center of the blade 12. That is, the secondary member is configured to cover the side wall portion (pressure surface) on the rotational direction side of the pump impeller 10 and the side wall portion (negative pressure surface) on the opposite side to the rotational direction with approximately the same thickness for the marked portion 121. By disposing the vane portion 120 (including the marked portion 121) of the primary member 100 as a core material in the center of the blade 12, manufacturing is easier in terms of the filling property and hardening time of the secondary member during the manufacturing process.

[0048] 5 is a diagram showing another specific example in which the vane portion 120 (marked portion 121) of the primary member 100 is arranged inside the blade 12 of the pump impeller 10 according to one embodiment of the present invention. As shown in FIG. 5, the marked portion 121 of the primary member 100 is arranged inside the blade 12 as viewed from the outer edge side of the main plate 11.

[0049] 5, the marking portion 121 is disposed away from the center of the blade 12 on the side opposite to the rotation direction of the pump impeller 10. In other words, the secondary member is configured to cover the side wall portion 12B of the marking portion 121 on the rotation direction side of the pump impeller 10 with a thickness greater than that of the side wall portion on the opposite side to the rotation direction.

[0050] In this way, by making the side wall portion 12B made of the secondary member thicker, the secondary member of the side wall portion 12B gradually wears away, and it takes longer for the marker portion 121 to appear on the surface, compared to the example shown in Fig. 4. In other words, the time until the marker portion 121 appears on the surface due to gradual wear of the secondary member can be adjusted depending on the position of the marker portion 121 arranged inside the blade 12 (the thickness of the secondary member covering the marker portion 121).

[0051] Here, the side wall portion 12B made of the secondary member has a large thickness, but if it is desired to shorten the time until the sign portion 121 appears on the surface, it may have a smaller thickness than the example shown in Figure 4.

[0052] 6 is a diagram showing another specific example in which the vane portion 120 (marked portion 121) of the primary member 100 is arranged inside the blade 12 of the pump impeller 10 according to one embodiment of the present invention. As shown in FIG. 6, the marked portion 121 of the primary member 100 is arranged inside the blade 12 as viewed from the outer edge side of the main plate 11.

[0053] In the example shown in Fig. 6, the sign portion 121 is configured to have a smaller height than the examples shown in Fig. 4 and Fig. 5. That is, the secondary member is configured to cover the tip portion 12C of the sign portion 121 with a thickness greater than that of one surface of the plate-like portion 110.

[0054] When the pump impeller 10 rotates, pressure from the fluid is exerted not only on the sidewall portion of the blade 12 in the rotation direction, but also on the tip portion of the blade 12. The secondary member also gradually wears away at the tip portion, causing the mark portion 121 to appear on the surface.

[0055] In this way, by making the tip portion 12C made up of the secondary member thicker, the secondary member of the tip portion 12C gradually wears away, and it takes longer for the marker portion 121 to appear on the surface, compared to the examples shown in Figures 4 and 5. In other words, the time it takes for the secondary member to gradually wear away and for the marker portion 121 to appear on the surface can be adjusted depending on the shape of the marker portion 121 arranged inside the blade 12 (the thickness of the secondary member covering the marker portion 121).

[0056] [Materials of Primary and Secondary Members] Regarding the materials forming the pump impeller 10, the primary member 100 is preferably a hard resin material as the core material of the pump impeller 10. For example, the primary member 100 is made of a material having a predetermined flexural modulus (e.g., 8000 MPa or more depending on the shape of the impeller and the required performance), and specifically, the primary member 100 may be a modified PPE (m-PPE, modified polyphenylene ether) resin or PPS (polyphenylene sulfide), which may contain glass fiber, calcium carbonate, or the like.

[0057] The secondary member is made of a resin material that is softer than the primary member 100, and is preferably made of, for example, a soft ether-based urethane that is excellent in abrasion resistance and hydrolysis resistance.

[0058] In this way, by producing the primary component 100 from a hard resin material, the degree of freedom in the product shape of the pump impeller 10 is improved, and a mono-material structure can be realized by not using a metal material as the core material. As a result, the pump impeller 10 can be easily thermally recycled and can be provided as an environmentally friendly product.

[0059] As described above, the pump impeller 10 according to one embodiment of the present invention is formed from a primary member 100 made of a hard resin material and a secondary member made of an ether-based urethane material that is softer than the primary member 100. The primary member 100 includes a substantially disk-shaped plate portion 110 and eight blade portions 120 formed on one side of the plate portion 110. The secondary member is configured to cover the primary member 100, and the primary member 100 and the secondary member are configured to be visually distinguishable. As a result, as the pump impeller 10 rotates, contaminants such as sand contained in the fluid that strikes the pump impeller 10 gradually wear the secondary member, causing the marking portion 121 on the primary member 100 to appear on the surface. As a result, the degree of wear on the pump impeller 10 can be easily determined, allowing appropriate determination of inspection and replacement times.

[0060] 2, the height (second height) of the rib portion 122 of the blade portion 120 in the primary member 100 is smaller than the height (first height) of the sign portion 121, but this is not limiting. For example, the height (first height) of the sign portion 121 and the height (second height) of the rib portion 122 may be the same, so that there is no boundary between the sign portion 121 and the rib portion 122, and the entire portion including the rib portion 122 may be the sign portion 121.

[0061] In addition, in this embodiment, the height (first height) of the sign portion 121 and / or the height (second height) of the rib portion 122 are constant, but this is not limited to this, and for example, they may be configured to gradually become smaller from the outer edge side toward the center side of the approximately disk-shaped plate-like portion 110.

[0062] Furthermore, all or part of the rib portion 122 does not have to be formed so as to protrude from one surface side of the plate-shaped portion 110. For example, as long as the strength required for the eight blades 12 of the pump impeller 10 is satisfied, the position of the primary member 100 corresponding to the blades of the pump impeller (the plate-shaped portion 110) may be flat.

[0063] [Another specific example (1) of the primary member] In the present embodiment, the marking portion 121 is formed only on the outer edge side of the substantially disk-shaped plate portion 110 of the blade portion 120, but this is not limited to this. Fig. 7 is a perspective view showing the appearance of a primary member 200 constituting the pump impeller 10 according to one embodiment of the present invention. As shown in Fig. 7, the primary member 200 differs from the primary member 100 shown in Fig. 2 in that each of the eight blade portions 220 includes two marking portions 221A, 221B and a rib portion 222.

[0064] Blade 220 has marker 221A on the outer edge side of substantially disc-shaped plate portion 110 of blade 120, and also has marker 221B on the central side. By forming marker 221B on the central side of substantially disc-shaped plate portion 110 of blade 220, marker 221B appears on the surface as the secondary member configured to cover marker 221B gradually wears away. In other words, when the central side of substantially disc-shaped plate portion 110 of blade 220 is severely worn away, the extent of the wear can be easily determined.

[0065] In this way, the sign portion may be formed not only near the outer region (the outer edge side of the plate-shaped portion 110) of the blade portion 120 (220), but also near the inner region (the side of the bearing portion 130) or near the middle region.

[0066] 7, the protrusions 140 may be formed one between each of the eight blade portions 120, for a total of eight. In FIG. 2, two protrusions 140 are formed between each of the eight blade portions 120, for a total of sixteen protrusions 140, but this is not limiting. The protrusions 140 are provided for fixing (aligning) to the mold, and therefore at least three protrusions 140 may be formed as long as they can be stably fixed to the mold.

[0067] On the other hand, depending on the material and shape of the primary member 100, the material of the secondary member, and the mold, many (more than 16) protrusions 140 may be formed to stably fix (align) the primary member 100 to the mold during the manufacturing process. For example, three or more protrusions 140 may be formed between each of the plurality of wing portions 120 formed on the plate-like portion 110, or protrusions 140 may be formed in the inner region in addition to the middle region and outer region.

[0068] Furthermore, if a jig or the like is used as a method for inserting and fixing the primary member 100 as the core material of the pump impeller 10 into a mold for molding the pump impeller 10, it is not necessary to provide such a protrusion 140.

[0069] 7, eight through holes 150 may be formed between each of the eight blade portions 120. In FIG. 2, one through hole 150 is formed between each of the eight blade portions 120 in the outer region, and four through holes 150 are formed along the outer periphery of the bearing portion 130 in the inner region, for a total of twelve through holes 150, but this is not limited to this. The through holes 150 are provided to ensure close contact between the primary member 100 and the secondary member, and therefore the number, position, and size of the through holes 150 may be set as appropriate as long as appropriate close contact between the primary member 100 and the secondary member can be ensured.

[0070] In this way, the number, positions, and sizes of the protrusions 140 and through holes 150 may be set as appropriate, and the primary member 100 is inserted into a mold for molding the pump impeller 10 and then the secondary member is filled in. However, when the secondary member is filled in, a large load is applied to the primary member 100 set in the mold, so it is preferable to form many protrusions 140 in order to prevent deformation of the primary member 100. Furthermore, when the secondary member is filled in, it is expected that the secondary member will flow in a balanced manner onto one side and the other side of the plate-like portion 110 through the through holes 150.

[0071] [Another specific example of primary member (2)] Figure 8 is a perspective view showing the appearance of a primary member 300 that constitutes the pump impeller 10 according to one embodiment of the present invention. As shown in Figure 8, the primary member 300 differs from the primary member 100 shown in Figure 2 in that a marking portion 321 is formed in the center of each of the eight blade portions 320.

[0072] As shown in FIGS. 2 and 7 , the blade 320 does not have a marking portion formed on the outer edge of the generally disc-shaped plate-like portion 110, but has a marking portion 321 formed in the center of the blade 320. For example, the blade 320 has a marking portion 321 formed near the middle region, a rib portion 322A formed near the outer region (the outer edge side of the plate-like portion 110), and a rib portion 322B formed near the inner region (the side of the bearing portion 130). As a result, as the secondary member configured to cover the marking portion 321 gradually wears, the marking portion 321 appears on the surface. In other words, when the blade 320 is severely worn from the center side of the generally disc-shaped plate-like portion 110, the extent of the wear can be easily determined.

[0073] Fig. 9 is an enlarged view showing details of the blade portion 320 of the primary member 300 shown in Fig. 8. As shown in Fig. 8, a marking portion 321 is formed in the center of the blade portion 320.

[0074] As the pump impeller rotates, a large pressure from the fluid is applied to the blades 12 of the pump impeller 10. At this time, pressure is applied to the blades 12 from various directions, not just from the sidewall portion on the rotational direction side of the blades 12 and the outer edge portion of the main plate 11, depending on the environment and conditions in which the pump is used and the type and amount of foreign matter contained in the fluid.

[0075] For example, in the region of the blade 12 on the bearing 130 side, the secondary member (above the rib 322B) covering the vane 320 may gradually wear, causing the indicator 321 to appear on the surface. In this case, the surface 321a of the indicator 321 shown in Fig. 9 that faces the bearing 130 may appear on the surface, making it easy to grasp the degree of wear of the pump impeller 10, and the timing of inspection and replacement may be appropriately determined.

[0076] [Another specific example of primary member (3)] Figure 10 is a perspective view showing the appearance of a primary member 400 that constitutes the pump impeller 10 according to one embodiment of the present invention. As shown in Figure 10, the primary member 400 differs from the primary member 100 shown in Figure 2 in that marking portions 421 are formed only on the outer edge sides of each of the eight blade portions 420.

[0077] As shown in FIGS. 2 , 7 , and 8 , the blade 420 does not have a marking on the center side (inner side) or near the center of the generally disc-shaped plate-like portion 110 of the blade 420, but has a marking 421 formed only on the outer edge of the blade 420. For example, the blade 420 may not have a rib portion as shown in FIGS. 2 , 7 , and 8 , or may have a rib portion formed only slightly around the periphery of the marking 421. This allows the marking 421 to appear on the surface as the secondary member configured to cover the marking 421 gradually wears. In the blade 12, when wear from the center side of the generally disc-shaped plate-like portion 110 is severe or when wear from the outer edge side is severe, the degree of wear can be easily determined. Furthermore, the configuration is simple.

[0078] In this embodiment, a pump impeller 10 having eight blades 12 has been described as an example, but this is not limited to this, and the pump impeller may have, for example, fewer than eight blades or nine or more blades.

[0079] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The elements of the embodiments, as well as their arrangement, materials, conditions, shapes, sizes, etc., are not limited to those illustrated and can be modified as appropriate. Furthermore, configurations shown in different embodiments can be partially substituted or combined with each other.

[0080] 10... Pump impeller, 11... Main plate (disk portion), 12... Blade, 13... Bearing portion, 14... Exposed portion, 100, 200, 300, 400... Primary member, 110... Plate-shaped portion, 120, 220, 320, 420... Blade portion, 121, 221A, 221B, 321, 321a, 421... Marking portion, 122, 222, 322A, 322B... Rib portion, 130... Bearing portion, 140... Protrusion portion, 150... Through hole, 12A, 12B... Side wall portion, 12C... Tip portion

Claims

1. A pump impeller for use in a water pump, formed of at least a primary member and a secondary member configured to cover the primary member, the primary member including a plate-like portion having a substantially disc shape and blade portions formed on one surface side of the plate-like portion so as to correspond to the blades of the pump impeller, the primary member and the secondary member being made of different resin materials, the pump impeller.

2. Among the blades of the pump impeller, at least a part of the blade portions formed by the primary member and at least a part formed by the secondary member so as to cover the blade portions are configured with different colors, the pump impeller according to claim 1.

3. Among the blades of the pump impeller, at least a part formed by the secondary member so as to cover the blade portions is configured to be transparent, the pump impeller according to claim 2.

4. The blade portions include a marking portion having a first height at at least a part of the blade portions, the pump impeller according to claim 1.

5. The secondary member is configured to cover the marking portion with substantially the same thickness for a side wall portion on the rotation direction side and a side wall portion on the side opposite to the rotation direction of the pump impeller, the pump impeller according to claim 4.

6. The secondary member is configured to cover the marking portion with a greater thickness for a side wall portion on the rotation direction side than a side wall portion on the side opposite to the rotation direction of the pump impeller, the pump impeller according to claim 4.

7. The secondary member is configured to cover a tip portion of the marking portion with a greater thickness than one surface side of the plate-like portion, the pump impeller according to claim 4.

8. The blade portions include a rib portion having a second height smaller than the first height among the blade portions, the pump impeller according to claim 4.

9. The secondary member is a resin material softer than the primary member, the pump impeller according to claim 1.

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