This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2013-036414, filed on Feb. 26, 2013, the entire contents of which are incorporated herein by reference.
(i) Technical Field
The present invention relates to an electric fluid pump.
(ii) Related Art
Japanese Patent Application Publication No. 2010-144693 discloses a technique for positioning an axial member by pushing the axial member against a metal mold when the axial member which supports a rotor is insert-molded with a case which has a recess portion housing the rotor.
However, as illustrated in FIGS. 1 and 3 of Japanese Patent Application Publication No. 2010-144693, an inner surface 22 of the recess portion housing the rotor is depressed to increase a capacity of the recess portion. Therefore, resistance of the fluid which has flowed into the recess portion might degrade rotation efficiency of the rotor. Further, in FIG. 6 of Japanese Patent Application Publication No. 2010-144693, depending on the flowing of the resin in insert molding, the resin preferentially flows to an inner side end surface 12b, so that the axial member might sink in a bottom wall portion of the recess portion. This might not ensure positional accuracy of the axial member.
According to an aspect of the present invention, there is provided an electric fluid pump including: a case including a recess portion into which a fluid flows; a rotor arranged in the recess portion; an axial member supporting the rotor; and a flange member insert-molded with the case and the axial member, secured to an end portion of the axial member, and buried in a bottom wall portion of the recess portion, wherein the flange member includes: a first flange portion; a reduced portion closer to an inner surface of the bottom wall portion than the first flange portion, and smaller than the first flange portion in a radial direction; and a second flange portion closer to the inner surface than the reduced portion, larger than the first flange portion in the radial direction, and partially exposed from the inner surface, and the inner surface is flat.
According to another aspect of the present invention, there is provided an electric fluid pump including: a case including a recess portion into which a fluid flows; a rotor arranged in the recess portion; an axial member supporting the rotor; and a flange member insert-molded with the case and the axial member, secured to an end portion of the axial member, and buried in a bottom wall portion of the recess portion, wherein the flange member includes: a flat plate portion partially exposed from an inner surface of the bottom wall portion; a groove portion formed at an outer circumferential portion of the flat plate portion; and a projection portion projecting from the groove portion so as to be distant from the inner surface, and the inner surface is flat.
According to another aspect of the present invention, there is provided an electric fluid pump including: a case including a recess portion into which a fluid flows; a rotor arranged in the recess portion; and an axial member including an end portion buried in a bottom wall portion of the recess portion, supporting the rotor, and being insert-molded with the case, wherein the end portion includes: a first flange portion; a reduced portion closer to an inner surface of the bottom wall portion than the first flange portion, and smaller than the first flange portion in a radial direction; and a second flange portion closer to the inner surface than the reduced portion, larger than the first flange portion in the radial direction, and partially exposed from the inner surface, and the inner surface is flat.
According to another aspect of the present invention, there is provided an electric fluid pump including: a case including a recess portion into which a fluid flows; a rotor arranged in the recess portion; and an axial member including an end portion buried in a bottom wall portion of the recess portion, supporting the rotor, and being insert-molded with the case, wherein the end portion includes: a flat plate portion partially exposed from an inner surface of the bottom wall portion; a groove portion formed at an outer circumferential portion of the flat plate portion; and a projection portion projecting from the groove portion to be distant away from the inner surface, and the inner surface is flat.
The case B includes a side wall portion 12 defining the recess portion S, and a bottom wall portion 14. The case B is made of a synthetic resin. The case B is insert-molded with the iron core 30, an axial member 40 supporting the rotor R for rotation, and a flange member 50 secured to an end portion 42 of the axial member 40. The iron core 30, the coils 34, and the pins CP are buried in the side wall portion 12. The end portion 42 of the axial member 40 and the flange member 50 are buried in the bottom wall portion 14. The axial member 40 is made of metal, and the flange member 50 is made of a synthetic resin. However, both may be made of metal or a synthetic resin.
The rotor R holds plural permanent magnets 46 which face the side wall portion 12 of the case B. An end side of the rotor R is provided with an impeller IP for introducing the fluid from the inlet 3 and discharging the fluid through the outlet 5.
The impeller IP is provided at an end portion 41 side of the axial member 40. A bearing V intervenes between the rotor R and the axial member 40. The bearing V is secured to the rotor R. The energization of the coils 34 excites the iron core 30 to have predetermined polarities, so that the rotor R is rotated by the magnetic force generated between the iron core 30 and the permanent magnets 46. Therefore, the impeller IP rotates.
Specifically, the end portion 42 of the axial member 40 is press-fitted into a hole 50h formed in the flange member 50. However, the present invention is not limited to this configuration. For example, both members may be secured by caulking. The flange member 50 includes a flange portion 51, a reduced portion 53, and a flange portion 55 in the order from the end portion 42 to the end portion 41 side. The reduced portion 53 is smaller than the flange portion 51 in the radial direction. The flange portion 55 is larger than each of the flange portion 51 and the reduced portion 53 in the radial direction.
As illustrated in
Also, as illustrated in
The resin is filled into the cavity CB, so that the resin flows between the flange portions 51 and 55. The force of the resin is applied to the flange portion 55 such that the flange portion 55 is pushed against the surface 82 of the metal mold 80. The force is applied to the flange portion 51 such that the flange portion 55 moves away from the surface 82. Here, the flange portion 55 is larger than the flange portion 51 in the radial direction, and also the area of the flange portion 55 is greater than that of the flange portion 51. Therefore, the force of the resin which pushes the flange portion 55 toward the metal mold 80 is greater than that of the resin which pushes the flange portion 51 to move away from the metal mold 80.
Thus, the force of the flowing resin maintains a state where the flange portion 55 of the flange member 50 is pushed against the surface 82 of the metal mold 80. Therefore, in the state where the flange member 50 and the axial member 40 are positioned with respect to the metal mold 80, the resin is hardened to form the case B. Accordingly, the positional accuracy of the axial member 40 is ensured.
Further, since the surface 82 is flat, the inner surface 14s of the bottom wall portion 14 of the case B also is formed into a flat shape. This suppresses an increase in the capacity of the recess portion S after formed. This also suppresses an amount of the fluid which flows into the recess portion S, thereby suppressing the rotation efficiency of the rotor R from deteriorating.
Also, the flange member 50 is formed by pressing. Thus, the manufacturing cost of the electric fluid pump 1 is reduced.
Next, a description will be given of an axial member 40a and a flange member 50a according to a variation embodiment.
The outer circumferential portion of the flat plate portion 51a is provided with plural groove portions 54a. The groove portion 54a is formed with a projection portion 55a which projects radially outward. The four groove portions 54a are provided at even angular intervals around the center of the axial member 40a. The projection portions 55a also have the same configuration. The projection portion 55a projects to the pipe portion 53a side from the flat plate portion 51a. Specifically, the projection portion 55a includes: a root portion 551a which projects from a bottom surface of the groove portion 54a and is curved; and an end portion 553a which projects from the root portion 551a in the direction perpendicular to the axial member 40a. The root portion 551a is curved to the pipe portion 53a side from the flat plate portion 51a. As illustrated in
Also, as illustrated in
The resin is filled into the cavity CB, so that the resin flows around the projection portions 55a at first. The resin flows not only to the upper side of the end portions 553a but also to the lower side thereof. Also, the resin flows to the lower side of the flat plate portion 51a. Therefore, the force of the resin is applied to the flat plate portion 51a such that the flat plate portion 51a is pushed against the surface 82 of the metal mold 80. The force is applied to the upper surfaces of the end portions 553a such that the end portions 553a move away from the surface 82. Here, the area of the lower surface of the flat plate portion 51a is greater than that of the upper surfaces of the end portions 553a. Therefore, the force of the resin which pushes the flange member 50a toward the metal mold 80 is greater than that of the resin which pushes the flange member 50a to move away from the metal mold 80.
Thus, the force of the flowing resin maintains a state where the flat plate portion 51a of the flange member 50a is pushed against the surface 82 of the metal mold 80. Therefore, in the state where the flange member 50a and the axial member 40a are positioned with respect to the metal mold 80, the resin is hardened to form the case. Accordingly, the positional accuracy of the axial member 40a is ensured.
Also, the flange member 50a is formed by pressing. Thus, the manufacturing cost of the electric fluid pump is reduced.
While the exemplary embodiments of the present invention have been illustrated in detail, the present invention is not limited to the above-mentioned embodiments, and other embodiments, variations and modifications may be made without departing from the scope of the present invention.
The flange member may be formed by cutting. Further, an axial member which is integrally formed with an flange member may be employed.
Number | Date | Country | Kind |
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2013-036414 | Feb 2013 | JP | national |
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Number | Date | Country |
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A-2010-144693 | Jul 2010 | JP |
Entry |
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Jun. 1, 2016 Extended Search Report issued in European Patent Application No. 14152012.2. |
Number | Date | Country | |
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20140241915 A1 | Aug 2014 | US |