1. Field of the Invention
The present invention relates to a circumferential flow pump which is accommodated in a fuel tank of a vehicle to press-feed fuel to an internal combustion engine, for example.
2. Description of the Related Art
A conventional circumferential flow pump is designed so that the groove cross-section area of an annular feed passage disposed in a pump cover and the groove cross-section area of an annular feed passage disposed in a pump base are set to be substantially equal to each other, and the dimension of a space formed in a vane wheel so as to confront the feed passage of the pump cover and the dimension of a space formed in the vane wheel so as to confront the feed passage-of the pump base are set to be substantially equal to each other, whereby the pressure balance in a pump chamber formed by the pump cover, the pump base and the vane wheel is made uniform as disclosed in Japanese Patent No. 2,962,828 (Patent Document 1).
In the conventional circumferential flow pump thus constructed, when fuel press-fed from the circumferential flow pump to the internal combustion engine is reduced, the pressure in the neighborhood of a discharge port of the pump base is increased and force acts on the vane wheel so that the vane wheel is pressed against the pump cover side. Therefore, the vane wheel is inclined and thus rotated while coming into contact with the pump cover or the pump base, so that the sliding resistance thereof is increased and the operating current of an electrically-driven motor for rotating the vane wheel is increased. In addition, the discharge amount is reduced, and the fuel press-fed from the circumferential flow pump to the internal combustion engine is reduced.
The present invention has been implemented to solve the above problem, and has an object to provide an efficient circumferential flow pump for press-feeding fuel to an internal combustion engine in which even when the pressure of fuel press-fed from the circumferential flow pump to the internal combustion engine is increased, the fuel press-fed from the circumferential flow pump to the internal combustion engine is prevented from being reduced.
In order to attain the above object, according to a first aspect of the present invention, a circumferential flow pump which press-feeds fuel and is equipped with a pump cover and a pump base constituting a pump chamber and a disc-shaped vane wheel rotating in the pump chamber and in which plural vane groove portions are formed along the outer peripheral wall of the vane wheel so as to penetrate through the vane wheel and so as to be trained in the outer peripheral direction of the vane wheel while partitioned by partition walls in the outer peripheral direction, and feed passages are formed in an annular form in the pump cover and the pump base respectively so as to face the vane groove portions of the vane wheel, is characterized in that a first groove sectional area (S1) of the feed passage at the pump cover side is set to be smaller than a second groove sectional area (S2) of the feed passage at the pump base side.
Furthermore, according to a second aspect of the present invention, a circumferential flow pump which press-feeds fuel and is equipped with a pump cover and a pump base constituting a pump chamber and a disc-shaped vane wheel rotating in the pump chamber and in which plural vane groove portions are formed along the outer peripheral wall of the vane wheel so as to penetrate through the vane wheel and so as to be trained in the outer peripheral direction of the vane wheel while partitioned by partition walls in the outer peripheral direction, and feed passages are formed in an annular form in the pump cover and the pump base respectively so as to face the vane groove portions of the vane wheel, is characterized in that a first spatial dimension (L1) formed in the vane wheel so as to confront the feed passage at the pump cover side is set to be smaller than a second spatial dimension (L2) formed in the vane wheel so as to confront the feed passage at the pump base side.
According to the present invention, in such a case that the fuel press-fed from the circumferential flow pump to an internal combustion engine is reduced, when the pressure of the fuel in the neighborhood of a discharge port of the pump base is increased, the pressure thus increased is balanced with the force for pressing the vane wheel to the pump cover side, and thus the vane wheel is not inclined. Therefore, the vane wheel is rotated with no occurrence of high sliding resistance between the pump base and the pump cover, so that the efficiency of the circumferential flow pump can be enhanced.
Preferred embodiments according to the present invention will be described hereunder with reference to the accompanying drawings.
In
A thrust block 5a for supporting the movement of the shaft 3a the electrically-driven motor 3 in the thrust direction and a suction port 5b for introducing fuel (not shown) to the vane wheel 2 are disposed at the center portion of the pump cover 5, and a metal 6a for supporting the rotation of the shaft 3a is disposed at the center portion of the pump base 6.
In
As shown in
Here, the position of the joint face 23c is set as a center line L, the distance from the end face 24 of the vane wheel 2 to the center line L is represented by L2, the distance from the end face 25 of the vane wheel 2 to the center line L is represented by L1, the space surrounded by the end face 25, the second circular bow portion 23b, the center line L and the outer peripheral wall 22 is set as a first space 23d, and the space surrounded by the end face 24, the first circular bow portion 23a, the center line L and the outer peripheral portion 22 is set as a second space 23e.
Furthermore, the feed passage 5c is formed by a first annular portion 52 formed so as to extend from a cross-point c of the end face of the cover end face 51 of the pump cover 5 with a radius of R2, and the feed passage 6b is formed by a second annular portion 62 formed so as to extend from a cross-point d of the base end face 61 of the pump base 6 with a radius of r2. The feed passage 5c at the pump cover side is set to a first groove cross section (S1), and the feed passage 6b at the pump base side is set to a second groove cross section (S2).
The operation of the circumferential flow pump 1 according to the present invention thus constructed will be described.
(1) When the fuel supply device 100 is immersed in a fuel tank (not shown), fuel flows through the suction port 5b into the vane groove portions 23.
(2) When power is supplied to the electrically-driven motor 3, the electrically-driven motor 3 is rotated, and thus the vane wheel 2 coupled to the shaft 3a of the electrically-driven motor 3 is rotated.
(3) When the vane wheel 2 is rotated, the vane wheel groove portions 23 are rotationally moved in the feed passage 5a and the feed passage 6a, whereby two eddy flows (indicated by arrows B of
(4) The kinetic energy of each of the eddy flows B is gradually more and more increased as the vane wheel 2 is rotated, and thus the fuel in the vane groove portions 23 is increased in pressure, so that the fuel thus pressure-increased is passed through the electrically-driven motor 3 and discharged from the discharge port 4, and then supplied to the internal combustion engine (not shown).
In the circumferential flow pump 1 according to the first embodiment, the first groove sectional area (S1) of the feed passage 5c at the pump cover 5 side is set to be smaller than the second groove sectional area (S2) of the feed passage 6b at the pump base 6 side, and thus the diameter of the eddy flow occurring in the first groove sectional area (S1) due to the rotation of the vane wheel 2 is smaller than the diameter of the eddy flow of the second groove sectional area (S2). Therefore, the flow rate of the eddy flow is increased, and the fuel pressure of the feed passage 5c at the pump cover 5 side is higher than that of the feed passage 6b at the pump base 6 side, and the vane wheel 2 is forced to be pressed to the pump base 6 side at all times. Accordingly, in such a case that the fuel press-fed from the circumferential flow pump 1 through the discharge port 4 to the internal combustion engine (not shown) is reduced, when the pressure in the neighborhood of the discharge port 6c of the pump base 6 is increased, the pressure thus increased is balanced with the force pressing the vane wheel 2 to the pump cover 5 side, and thus the vane wheel 2 is not inclined. Therefore, the vane wheel 2 is rotated with no occurrence of high sliding resistance between the pump base 6 and the pump cover 5, so that the efficiency of the circumferential flow pump can be enhanced.
A circumferential flow pump 1 according to a second embodiment of the present invention is designed so that the first spatial dimension (L1) formed in the vane wheel 2 so as to confront the feed passage 5c at the pump cover 5 side is smaller than the second spatial dimension (L2) formed in the vane wheel 2 so as to confront the feed passage 6b at the pump base 6 side in
In the circumferential flow pump 1 according to the second embodiment thus constructed, the first spatial dimension (L1) formed in the vane wheel 2 so as to confront the feed passage 5c at the pump cover 5 side is smaller than the second spatial dimension (L2) formed in the vane wheel 2 so as to confront the feed passage 6b at the pump base 6 side, so that the diameter of the eddy flow occurring in the first space 23d is smaller than the diameter of the eddy flow occurring in the second space 23e. Therefore, the flow rate of the eddy flow in the first space 23d is increased, the fuel pressure of the feed passage 5c at the pump cover 5 side is higher than that of the feed passage 6b at the pump base 6 side, and the vane wheel 2 is forced to be pressed to the pump base 6 side at all times. Accordingly, in such a case where the fuel press-fed from the circumferential flow pump 1 through the discharge port 4 to the internal combustion engine (not shown) is reduced, when the pressure in the neighborhood of the discharge port 6c of the pump base 6 is increased, the increased pressure is balanced with the force for pressing the vane wheel 2 to the pump cover 5 side. Therefore, the vane wheel 2 is not inclined, and the it is rotated with no occurrence of high sliding resistance between the pump base 6 and the pump cover 5, whereby the efficiency of the circumferential flow pump is enhanced.
Number | Date | Country | Kind |
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P2004-351259 | Dec 2004 | JP | national |