JP2003278684A - Fluid suction/exhaust device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid suction/exhaust device capable of lowering noise due to arrangement at unequal intervals in spite of its uneven-interval arrangement of blades. <P>SOLUTION: In this fluid suction/exhaust device having blades 24a and an impeller 24 having blade grooves 24b arranged between the blades 24a in its circumference, sucked fluid is discharged by rotation of the impeller 24. An adjacent angle Θ of the blade grooves 24b is set according to a predetermined periodic function and arranged in the circumference direction. Desirably, the periodic function is defined as Θ(no)=360/[N+Kcosä2π/N/(no-1)}] when a predetermined blade groove Θ1 is used as a reference, the blades 24 are numbered with (no), and the adjacent angle matching the blade 24a (no) with the number (no) is represented by Θ(no). In this expression, N represents the total number of blades, and K represents a coefficient varying the degree of influence of a trigonometric function cos. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid intake / exhaust device, and in particular, it sucks fuel as a fluid from a fuel tank.
A fuel pump for discharging.

[0002]

2. Description of the Related Art As a fluid intake / exhaust device, for example, in a fuel supply device for an internal combustion engine, a rotary member, which is formed in a disk shape and has blades on its outer peripheral edge, rotates to intake and exhaust fuel which is a fluid. A fuel pump that discharges fuel sucked up from a so-called fuel tank is known.

In this type of fluid suction / discharge device, a plurality of blades provided on the outer peripheral edge of the rotary member are arranged at equal intervals in the circumferential direction. When the rotating member rotates, the blade passes through a partition wall provided on the side of the housing that houses the rotating member and adjacent to the blade between the fuel intake mouth and the discharge port at regular intervals. Therefore, a so-called metallic sound of a predetermined high frequency corresponding to the number of blades / (the number of rotations of the rotating member) is generated.

As a countermeasure against this, there is a technique in which the blade intervals are randomly arranged so that the blade intervals do not become constant and uniform (Japanese Patent Laid-Open No. 11-50990).

According to Japanese Patent Laid-Open No. 11-50990,
Arrange the wings randomly. Arranging in a random number is not just arranging at random but, for example, the total angle of a predetermined number of blade intervals, within the range of the predetermined number,
Even if the blades that start to calculate the total angle are shifted in the circumferential direction, the blades are made uniform so that they are within a certain total angle range. It is arranged with this uniformization, that is, with the addition of arbitrary selection.

[0006]

However, in this conventional configuration, since they are arranged in a random number after all, there is a possibility that sound pressure peaks overlapping at n times the frequency of the rotation order of the rotating member may occur. In some cases, resonance may increase noise in the frequency range of the sound pressure peak.

The present invention has been made in consideration of the above circumstances, and an object thereof is to avoid an increase in noise due to an array of unequal intervals in a case provided with blades arranged at unequal intervals. It is to provide a possible fluid suction and discharge device.

Another object of the present invention is to provide a fluid suction / discharge device which can secure a desired discharge amount as the flow rate of the fluid discharged from the discharge port.

[0009]

According to the first aspect of the present invention, there is provided a blade, and a rotary member having a blade groove provided between the blades arranged around the blade, and the fluid sucked by the rotation of the rotary member is discharged. In the fluid suction and discharge device, the adjoining angles of the blade grooves are set in a predetermined periodic function and arranged in the circumferential direction.

As a result, when the adjoining angles of the blade grooves are set, the frequency range of the sound pressure peak is dispersed in a specific frequency range by changing with a periodic function, as compared with the conventional arrangement in which the blade grooves are randomly arranged. It is possible. Therefore, the sound pressure energy can be widely dispersed in a specific frequency range, and the sound pressure at the sound pressure peak can be reduced.

The periodic function for determining the adjoining angle Θ of the blade grooves is, as described in claim 2 of the present invention, a predetermined blade groove as a reference, and the blade is given a number no. Let Θ (no) be the adjoining angle corresponding to the blade of Θ: Θ (no) = 360 / [N + Kcos {2π / N · (n
o-1)}] where N is the total number of blades and K is a mathematical expression represented by a coefficient that changes the degree of influence of the trigonometric function cos.

As a result, when the adjoining angles are not at least equidistantly spaced, a predetermined cycle fluctuation is made corresponding to the blade number number no, based on the average adjoining angle of 360 / N in the total number N of the blades. Give Kcos {2π / N ・
By adding (no-1)} to the parameter N, it is possible to form an array of adjacent angles having regularity. Therefore, it is possible to avoid an increase in noise due to an accidental unequal interval such as a random arrangement.

Further, since the array of the adjoining angles Θ is set by a periodic function including Kcos {2π / N · (no-1)} which gives a periodic variation, by changing the coefficient K of the trigonometric function cos, The sound pressure energy generated in the frequency range of the sound pressure peak can be dispersed into the sound pressure energy in a specific frequency range, that is, a frequency band having a predetermined frequency width corresponding to the coefficient K. Therefore, the maximum sound pressure in the frequency range of the sound pressure peak can be reduced.

According to claim 3 of the present invention, in the above periodic function, the coefficient K is 6 or more.

Thus, for example, in the case of being applied to a fluid intake / exhaust device as a fuel supply device for an internal combustion engine, a frequency band higher than the frequency band in which combustion noise is generated is 4 kHz.
It is possible to reduce the maximum noise at the sound pressure peak caused by the blade arrangement of the rotating member of the fluid suction / exhaust device in the frequency range of z or higher to a predetermined sound pressure or lower. For example, even in an operating state where the combustion noise is relatively small, that is, in the idle state of the internal combustion engine, the noise level in the frequency band that can be distinguished from the combustion noise, that is, the maximum noise of the sound pressure peak is suppressed to a predetermined sound pressure or less, which is annoying. It is possible to prevent the generation of perceived noise.

According to claim 4 of the present invention, in the above periodic function, the coefficient K is in the range of 6≤K≤14.

As a result, in order to disperse the sound pressure energy generated in the frequency range of the sound pressure peak, for example, the frequency of the peak part of the sound pressure on the lower limit side of the frequency band expanded to a predetermined frequency width is 4 kHz. It is possible to prevent the occurrence of the following combustion sound generation zone.

According to claim 5 of the present invention, in the above periodic function, the coefficient K is in the range of 6≤K≤10.

As a result, it is possible to secure a desired discharge amount of the fluid discharged from the fluid suction / discharge device without increasing the size of the body. For example, when applied to a fluid intake / exhaust device as a fuel supply device for an internal combustion engine, it is possible to easily secure a required discharge amount required to secure a fuel pressure of fuel to be supplied.

According to claim 6 of the present invention, the rotary member is suitable for a fuel pump having an impeller for discharging the fuel sucked from the fuel tank.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a fluid intake / exhaust device of the present invention will be described.
A specific embodiment applied to a fuel pump of an internal combustion engine will be described with reference to the drawings. FIG. 1 shows an impeller of a fuel pump to which a fluid intake / exhaust device of an embodiment of the present invention is applied, and is a schematic plan view seen from I-I in FIG. 2. FIG. 2 is a cross-sectional view showing a schematic configuration of a fuel pump including the fluid suction / discharge device according to the embodiment of the present invention. FIG. 3 is a graph showing the relationship between frequency and sound pressure in one embodiment of the present invention. FIG. 4 is a schematic diagram showing the relationship between frequency and sound pressure according to the embodiment of the present invention, and FIG.
(B) is a schematic diagram showing the relationship between frequency and sound pressure by changing the coefficient K of the periodic function, which is a feature of the present invention. 5 is shown in FIG.
2 is a graph showing the performance of the fuel pump provided with the fluid intake / exhaust device according to the embodiment of the present invention shown in FIG.
Maximum sound pressure value in the frequency range of -10 kHz, and FIG.
FIG. 3 is a schematic diagram showing the relationship with the fluid intake / exhaust device shown in FIG. 1, that is, the discharge flow rate of the fuel pump.

The fuel pump 10 is mounted in, for example, a fuel tank of a vehicle or the like, and supplies fuel from the fuel tank to a fuel injection device of an internal combustion engine. The fuel pump 10
A pump unit 10a that sucks and pressurizes fuel from a fuel tank (not shown), and a motor unit 10 that drives the pump unit 10a.
b, and a fuel discharge part 10c for discharging the fuel pressurized by the pump part 10a to the outside of the fuel pump. Pump section 1
0a forms a C-shaped pump chamber 30 between the pump cover 12 and the pump casing 13, and a disc-shaped impeller 24 serving as a rotary member for fuel pressurization is rotatable in the pump chamber 30. It is housed in. Pump cover 1
2 and the pump casing 13 are made of aluminum, and are fixed by caulking to one end of a housing 11 formed in a cylindrical shape.

As shown in FIG. 1, the impeller 24 as a rotating member has 67 blades 24a on the outer peripheral edge and blades 24a.
67 blade grooves 24b are provided between a. Feather 2
The width of the blades 4a is substantially constant, but the pitch between the adjacent blades 24a, that is, the adjacent angle of the blade grooves 24b are all different. The fuel sucked into the pump chamber 30 through the suction port 31a formed in the pump cover 12 is pressurized by the rotation of the impeller 24, and is delivered from the discharge port 31b to the motor chamber 32 of the motor unit 10b. The partition wall 13a formed in the pump casing 13 is close to the outer circumference of the impeller 24 and seals the suction port 31a and the discharge port 31b.

The motor unit 10b shown in FIG. 2 has a rotor 20 and a magnet 25 surrounding the rotor 20, and the coil 20a of the rotor 20 arranged in the magnetic field of the magnet 25 has the connector 50 of the connector 50. When current is supplied from the connector pin 51, the rotor 20 rotates. A thrust shaft 22 of the rotor 20 on the thrust direction side is supported by a thrust bearing 22 which is press-fitted into a central recess of the pump cover 12. The rotary shaft 21 is axially supported by a thrust bearing 22 and radially supported by a bearing 26. The other rotating shaft 23 of the rotor 20 is supported by a bearing 27 in the radial direction. A notch 21a is provided on the outer peripheral wall of the rotary shaft 21 in the axial direction.
The impeller 24 is fixed to the portion where the is formed.

The magnet 25 is provided on the outer periphery of the rotor 20 and forms a predetermined air gap with the rotor 20. A commutator 40 made of copper, which is divided into eight segments, is installed on the rotary shaft 23 side of the rotor 20. The discharge case 14 is fixed to the other end of the housing 11 by caulking. The connector pin 51 is embedded in the connector 50 provided in the discharge case 14 with its tip exposed. The connector pin 51 is connected to the rotor 20 via the brush and the commutator 40.
The coil 20a is connected to the coil 20a and is connected to the choke coil 52. The choke coil 52 is connected to remove the AC component from the current supplied to the coil 20a.

The discharge portion 10c accommodates a check valve 34 in the discharge port 33 formed in the discharge case 14, and the check valve 34 prevents the backflow of the fuel discharged from the discharge port 33. Next, the operation of the fuel pump 10 will be described. Coil 2
When a current is supplied to 0a, the rotor 20 rotates with the rotating shaft 21 supported by the thrust bearing 22 and the bearing 26 and the rotating shaft 23 supported by the bearing 27. The fuel sucked up from the fuel tank into the pump chamber 30 through a filter (not shown) is pressurized in the pump chamber 30 by the impeller 24 rotating with the rotary shaft 21, and is delivered to the motor chamber 32. The fuel delivered to the motor chamber 32 pushes up the check valve 34 of the discharge port 33 and is discharged from the discharge port 34 to the outside of the fuel tank through a fuel pipe (not shown).

When the impeller 24 rotates, each blade 24a
The pressure difference generated before and after the rotational direction of the above-mentioned impinges on the partition wall 13a of the pump casing 13 near the outer circumference of the impeller 24. Depending on how to set the adjoining angles of the blade grooves 24b provided in the impeller 24, a loud noise may be generated when fuel having a pressure difference collides with the pump cover 12 and the partition wall 13a of the pump casing 13.

Next, the arrangement of the blade grooves 24b of the impeller 24, which is a feature of the present invention, particularly the arrangement of the blade grooves adjacent to each other will be described.

First, the blades 24a and the blade grooves 24b arranged around the impeller 24 are numbered in the circumferential direction, for example, in the rotation direction of the impeller 24 to define the array number.
In this embodiment, the total number N of blades arranged on the impeller 24 is 47 (N = 47). As shown in FIG. 1, the adjoining angle Θ of the blade groove 24b is changed to the adjoining angle Θ.
It is defined by being associated with the numbering no of the blade 24a standing inside (specifically, the i-th adjacent angle Θ is numbered i).
Corresponding to the blade 24a (i) of No. That is, as shown in FIG. 1, the first adjoining angle Θ (1) serving as the arrangement start point of the blade grooves 24b is the first blade 24a (1) and the 47th blade 24a (47). With reference to the center of the blade groove 24b (1) formed between the two, the center-to-center angle to the center of the second blade groove 24b (2) is defined. Similarly, the i-th adjacent angle Θ (i) is measured from the center of the i-th blade groove 24b (i) to the (i + 1) th angle.
It is represented by the center-to-center angle to the center of the th blade groove 24b (i + 1). At this time, before obtaining the i-th adjacent angle Θ (i), the adjacent angle Θ (1) to the (i-1) -th adjacent angle Θ (i- of the first blade groove 24b (1) are obtained. 1)
Blades 2
The arrangement of 4 (i) is automatically determined.

Next, a method of setting the adjacent angles Θ of the blade grooves 24b will be described below. As described above, with reference to the predetermined blade groove 24b (1), the blade 24
a is a numbered no (more specifically, the numbered numbers are 1, 2, ...
i ,. ． ． , 47), and the blade number 24a of the numbered No.
(Specifically, the adjacent angle corresponding to 24a (no) is represented by Θ
When (no),

[0031]

## EQU00001 ## .THETA. (No) = 360 / [N + Kcos {2.pi.
/N.(no-1)}]. Here, in Expression 1, K is a coefficient that changes the degree of influence of the trigonometric function cos. Furthermore, when K = 0, the arrangement of the adjoining angles Θ (no) will be at equal intervals, so they are not included in the present invention.

As a result, when the adjoining angle Θ of the blade groove 24a is set, the frequency of the sound pressure peak is changed by changing with a function including a periodic function, that is, a trigonometric function cos, as compared with the conventional arrangement in which random numbers are arranged. It is possible to distribute the range over a specific frequency range (see FIG. 5). Therefore, the sound pressure energy can be widely dispersed in a specific frequency range, and the sound pressure at the sound pressure peak can be reduced (see FIG. 5).

The arrangement of the adjoining angles Θ of the blade grooves 24a according to one embodiment of the present invention, the arrangement of arranging the conventional adjoining angles Θ at equal intervals (hereinafter referred to as the equal interval arrangement), and the arrangement at random. The following is a description of the arrangement (hereinafter, referred to as an unequal-spaced arrangement based on a random number arrangement), which has been subjected to noise evaluation experiments, with reference to FIGS. 6, 7, and 3. FIG. 6 is a graph showing a relationship between frequency and sound pressure in a configuration in which adjacent angles of blade grooves of a conventional example are randomly arranged, and FIG. 7 shows frequency in a configuration in which adjacent angles of blade grooves of a conventional example are arranged at equal intervals. It is a graph which shows the relationship of sound pressure. As shown in FIG. 7, the adjacency angle Θ
In the case of simply arranging them at equal intervals, a so-called first-order rotational sound pressure peak corresponding to the total number N of the blades 24a of the impeller 24 and the number of revolutions is shown (for example, in the present embodiment, the frequency range is 5).
Resonance that maximizes the sound pressure peak occurs at up to 6 kHz, and the sound pressure maximum value Pf3 occurs about 147 (dB). On the other hand, in the case of the non-equidistant array by the conventional random number arrangement, the resonance is alleviated at the frequency range of 5 to 6 kHz shown in FIG. 7, but after all, since the arrangement is made in the random number, There is no guarantee that the sound pressure peak in the frequency range will not increase. Figure 6
As shown in, when compared with an equidistant array (see FIG. 7),
Depending on the random number arrangement, the sound pressure decreases in the frequency range of 5 to 6 kHz, but the sound pressure increases conversely at the frequency range of 7 to 8 kHz, and the sound pressure peaks at the peak. . The maximum value Pf2 at that time is shown in FIG.
Is about 141 (dB), for example.

On the other hand, in the arrangement of the adjoining angles Θ (no) of the blade grooves 24a of the present invention, a periodic function (details) in a specific frequency range (for example, a frequency band of about 4.5 to 7 kHz shown in FIG. 3) is provided. Can be widely distributed without bias due to the trigonometric function cos). The maximum value Pf1 of the sound pressure peak generated at that time is about 135 (dB), and noise can be reduced (Pf1 <Pf2 <Pf3).

More specifically, when the adjoining angles Θ are not at least equally spaced by the periodic function, the average adjoining angle in the total number N of the blades 24a is 360 / N.
Is used as a reference, and Kcos {2π / N · (no-
1)} is added to the parameter N, it is possible to form an array of adjacent angles having regularity. Therefore, it is possible to avoid an increase in noise due to accidental unequal array arrangement such as random arrangement. Furthermore, the array of adjacent angles Θ (no) is given by Kcos {2π / N · (no-
1)} is set by a periodic function, the sound pressure energy generated in the frequency range of the sound pressure peak is changed by changing the coefficient K of the trigonometric function cos to a specific frequency range, that is, a predetermined frequency corresponding to the coefficient K. The sound pressure energy can be dispersed in a frequency band having a width (see FIGS. 4 and 5). Therefore, as shown in FIG. 5, the maximum sound pressure in the frequency range of the sound pressure peak can be reduced.

In FIG. 4, the horizontal axis represents frequency (kH
z) and the vertical axis is a sound pressure level (dB) representing the magnitude of sound pressure energy, and FIGS.
The coefficient K for changing the degree of influence of the periodic fluctuation factor (trigonometric function cos) of K = 0, 2, 4, 6, 8, 10, 1
It is the result of noise evaluation by experiment by manufacturing the impeller 24 in which 2 and 14 were changed. As shown in FIG. 4, as the coefficient K increases, the frequency width of a specific frequency range for distributing the sound pressure energy can be expanded. Therefore, the sound pressure energy generated in the frequency range of 5 to 6 kHz in which the first-order rotation resonates, which is generated in the conventional equidistant arrangement, is
The sound pressure energy can be dispersed over a specific frequency range having a predetermined frequency width according to the coefficient K. As shown in the relationship between the maximum sound pressure value and the coefficient K in FIG. 5, the larger the coefficient K is, the more the maximum value of the sound pressure peak in the frequency range of 0 to 10 kHz can be reduced.

Here, in the array of adjacent angles Θ (no) using the so-called periodic function of the present invention, a coefficient K for controlling the degree of influence of the trigonometric function cos as the periodic function, and 0
The relationship between the maximum value that becomes the sound pressure peak in the frequency range of 10 kHz and the discharge flow rate from the viewpoint of the fuel pump that feeds fuel to the internal combustion engine will be described with reference to FIG.

The combustion noise of an internal combustion engine is generally about 1 to 3 kH.
It occurs in the z frequency band. Therefore, in an operating state in which combustion noise is relatively small, for example, in an idling state of the internal combustion engine, noise other than combustion noise may be noise that makes passengers in the vehicle feel uncomfortable. Particularly in the case of device noise that produces a so-called metallic high-frequency sound that occurs in a frequency band different from that of the combustion sound, it is desirable to make the sound pressure at least smaller than the maximum value.

On the other hand, in the embodiment of the present invention, the coefficient K is set to 6 or more in the array of the adjoining angles Θ (no) (specifically, the mathematical expression 1) using the above periodic function.
As shown in, the maximum noise of the sound pressure peak caused by the arrangement of the blades 24a of the impeller 24 of the fuel pump, which is generated in the frequency range of 4 kHz or more, which is a higher frequency band than the frequency band in which the combustion noise is generated, is Can be reduced to That is, the noise level in the frequency band distinguishable from combustion noise, that is, the maximum noise Pf at the sound pressure peak.
Is suppressed to a predetermined sound pressure Pfa (for example, idle combustion sound) or less, it is possible to prevent noise that is offensive to the ear.

Furthermore, in the array of adjacent angles Θ (no) using the above periodic function (specifically, Formula 1), the coefficient K may be set within the range of 6 ≦ K ≦ 14.

As a result, in order to disperse the sound pressure energy generated in the frequency range of the sound pressure peak, for example, the frequency of the peak part of the sound pressure on the lower limit side of the frequency band expanded to a predetermined frequency width is 4 kHz. It is possible to prevent the occurrence of the following combustion sound generation zone (see FIG. 4 (h)).

Furthermore, in the array of adjacent angles Θ (no) using the above periodic function (specifically, Formula 1), the coefficient K may be set within the range of 6 ≦ K ≦ 10.

As a result, it is possible to secure a desired discharge amount without increasing the size of the fluid discharged from the fuel pump. More specifically, in the embodiment shown in FIG. 5, if a discharge flow rate reduction of 5% is within the error range (a predetermined discharge amount Qa that is an error range with respect to the required discharge amount), K
When ≦ 10, it can be suppressed to about 3%. Therefore, when applied to a fluid intake / exhaust device as a fuel supply device for an internal combustion engine, it is possible to easily ensure the required discharge amount required to ensure the fuel pressure of the fuel to be supplied.

The adjacent angle Θ (n
The mathematical formula for determining the arrangement of o) is not limited to the mathematical formula 1, and the adjacency angle Θ (no) is calculated using a periodic function.
Can be any equation as long as it can be controlled within a predetermined variation range, that is, an array with unequal intervals can be generated within the predetermined variation range.

[Brief description of drawings]

FIG. 1 shows an impeller of a fuel pump to which a fluid intake / exhaust device according to an embodiment of the present invention is applied, which is I- in FIG.
It is a schematic plan view seen from I.

FIG. 2 is a cross-sectional view showing a schematic configuration of a fuel pump including the fluid suction / discharge device according to the embodiment of the present invention.

FIG. 3 is a graph showing the relationship between frequency and sound pressure according to the embodiment of the present invention.

FIG. 4 is a schematic diagram showing a relationship between frequency and sound pressure in the embodiment of the present invention, and FIGS. 4A to 4H show the frequency and the frequency by changing the coefficient K of the periodic function which is a feature of the present invention. It is a schematic diagram which shows the relationship of sound pressure.

5 is a graph showing the performance of the fuel pump including the fluid intake / exhaust device according to the embodiment of the present invention shown in FIG.
FIG. 3 is a schematic diagram showing a relationship between a coefficient K, a maximum sound pressure value in a frequency range of 0 to 10 kHz, and a discharge flow rate of the fluid suction / exhaust device shown in FIG. 2, that is, a fuel pump.

FIG. 6 is a graph showing a relationship between frequency and sound pressure in a configuration in which adjacent angles of blade grooves of a conventional example are randomly arranged.

FIG. 7 is a graph showing the relationship between frequency and sound pressure in a configuration in which adjacent angles of blade grooves of a conventional example are arranged at equal intervals.

[Explanation of symbols]

10 Fuel pump (fluid suction / discharge device) 11 housing 12 Pump cover 13 Pump casing 13a partition wall 24 Impeller (rotating member) 24a feather 24b blade groove Total number of N blades no numbering Θ Adjacent angle (angle between centers, pitch) K coefficient

Claims (6)

[Claims] 1. A fluid intake / exhaust device that has blades and a rotating member around which blade grooves provided between the blades are arranged, and discharges the fluid sucked in by the rotation of the rotating member. A fluid intake / exhaust device in which angles are set by a predetermined periodic function and arranged in the circumferential direction. 2. The periodic function for determining the adjacent angle Θ of the blade groove corresponds to the blade of the numbered no by assigning a number no to the blade with reference to the predetermined blade groove. When the adjoining angle is set to Θ (no), Θ (no) = 360 / [N + Kcos {2π / N · (n
o-1)}] where N is a total number of the blades and K is a mathematical expression represented by a coefficient that changes the degree of influence of the trigonometric function cos. 3. The coefficient K in the periodic function is 6
It is above, The fluid intake-and-exhaust device of Claim 2 characterized by the above-mentioned. 4. In the periodic function, the coefficient K is 6
The fluid intake / exhaust device according to claim 2, wherein ≦ K ≦ 14. 5. The coefficient K in the periodic function is 6
The fluid intake / exhaust device according to claim 2, wherein ≦ K ≦ 10. 6. The fluid intake / exhaust device according to claim 1, wherein the rotary member is an impeller of a fuel pump that discharges fuel sucked from a fuel tank.