CN100378319C - turbo fuel pump - Google Patents

Abstract

The turbo fuel pump includes an impeller having a plurality of blades, each of which includes a straight blade portion extending linearly in the radial direction of the impeller, and a circular blade on the front side from the head of the straight blade portion toward the direction of rotation of the impeller. It consists of a curved blade section that extends in a curved manner. The length of the straight blade portion is (1/3 to 2/3) x H, where H is the total length of the impeller.

Description

turbo fuel pump

This application is a divisional application of the invention patent application with application number 03136325.3. The filing date of the original application was May 28, 2003, and the title of the invention was "turbine fuel pump".

technical field

The invention relates to turbo fuel pumps suitable for use, for example, in delivering fuel to injection valves and the like of motor vehicle engines.

Background technique

Usually, in order to deliver fuel to the engine, an electronically controlled fuel injection system is installed on the passenger car. The fuel injection system has an injection valve that injects fuel into the combustion chamber of the engine, and delivers the fuel in the fuel tank, such as at the rear of the vehicle, to the injection valve for the fuel pump. Recently, there has been an increased demand for improvement in fuel consumption of vehicles due to social demands for global environmental protection. Therefore, an important challenge for electric motor driven fuel pumps is to achieve increased efficiency (ie reduced electrical power consumption) and reduced size and weight.

In normal use, the fuel pump includes a turbo fuel pump, the turbo fuel pump has a cylindrical housing for accommodating the electric motor, an upper cover mounted on one end of the housing, and a cover mounted on the other end of the housing for supporting the motor and having a The casing of the annular fuel passage between the oil port and the oil outlet, and an impeller rotatably installed in the casing. When the impeller is rotated by the motor, the impeller sends the fuel sucked in from the oil inlet through the fuel passage to the outlet. oil port.

The impeller is shaped like a disc with radially extending vanes arranged circumferentially on the outer periphery and vane grooves formed between the vanes. The fuel sucked in from the oil inlet is introduced into the vane groove through the fuel channel to receive the kinetic energy from the vane, and then is discharged to the channel. The fuel discharged to the fuel passages circulates in the passages, and then the fuel is directed into the vane grooves. Fuel in the passage builds up pressure in repeated inflow and outflow, and is expelled through the outlet.

Improving the efficiency of the fuel pump is important to improving both the efficiency of the electric motor and the efficiency of the pump section. In particular, the impeller is driven by an electric motor turning in fuel, with torque losses due to the viscosity of the fuel. The impeller also suffers torque losses due to the viscosity of the fuel when turning within the housing. These torque losses increase in proportion to the square of rpm (revolutions per minute), so torque losses become very large when the fuel pump operates at high rpm, resulting in a reduction in pump efficiency.

By sizing the pump section, the desired flow rate can be achieved at low rpm and torque losses can be contained. In this case, however, the torque required to drive the impeller increases.

In addition, due to the need to reduce the size of the fuel pump, the electric motor is also reduced in size. As mentioned above, generating high torque at low rpm requires the motor to operate in a low efficiency range. Thus, not only is it important to improve pump efficiency by sizing the pump section so that torque loss is minimized, but also sizing the motor so that it can operate within a high efficiency range.

In terms of improving the efficiency of turbo fuel pumps, various impeller improvements have been proposed. One of the improvements is disclosed in JP-A8-100780, in which each blade of the impeller has a root that is bent backward as viewed in the direction of rotation of the impeller, and the head is inclined linearly backward from the curved portion radially stick out. Even in the relatively low rpm range, this shape of the vanes allows for a smooth flow of fuel from the vane grooves to the passages, preventing the flow rate from decreasing with rpm, improving low pressure performance and flow rate control.

In the fuel pump disclosed in JP-A8-100780, as mentioned above, each blade of the impeller has a root portion bent backward as viewed from the direction of rotation of the impeller, and the head is linearly inclined backward from the curved portion along the radial direction. Stretch out. In this way, the impeller prevents the flow rate from decreasing with rpm in the relatively low rpm range. However, since the impeller has a rectilinearly inclined head. The fuel flows out of the vane grooves in the rear direction, which cannot give the fuel high kinetic energy. Thereby, a considerable increase in rpm is required to achieve a relatively large flow rate. This leads to an increase in torque loss over a relatively large flow rate range, creating a problem of lowering pump efficiency.

Contents of the invention

It is therefore an object of the present invention to provide a turbo fuel pump which improves pump efficiency over the entire operating range.

The present invention generally provides a kind of fuel pump, and it has: a casing that accommodates electric motor, is contained on casing, and casing has the annular channel between inlet and outlet; It has blades arranged on the outer circumference of the impeller and extending radially along it. When the blades are rotated by the motor, the fuel is delivered through the channel. Each blade has a straight line extending along the radial direction of the impeller and a The head of the straight portion is curved in a circle toward the curved portion extended on the front side of the impeller, and the straight portion has a predetermined length, which is (1/3 to 2/3)×H, where H is the total length of the impeller.

One aspect of the present invention is to provide a turbo fuel pump, which has: a housing containing the motor, a housing mounted on the housing, the housing has an annular passage between the inlet and the outlet; rotatably mounted in the housing The impeller has blades arranged on the outer circumference of the impeller and extending radially along it. When the blades are rotated by the motor, the fuel is delivered through the channel. Each blade has a plate with a substantially rectangular cross-section. In front of the front side, behind the impeller on the rear side, and on a pair of sides between the front and back, each blade has a chamfer extending radially of the impeller on the side of the blade root, the The chamfer is obtained by obliquely cutting off the corner between the side and the rear of the blade, and the chamfer has a predetermined length, where the predetermined length is (2/5 to 3/5)×L, where L is the length of the channel radial length.

Description of drawings

Other objects and features of the invention will be apparent from the following description with reference to the accompanying drawings, in which:

Fig. 1 is a longitudinal sectional view of a first embodiment of a turbo fuel pump according to the present invention;

Figure 2 is a partially enlarged view of Figure 1;

Fig. 3 is a sectional view taken along line III-III in Fig. 2;

Figure 4 is an enlarged perspective view of the impeller blade;

Figure 5 is a plan view of the impeller blade;

6 is a graph showing the relationship between the position of the starting point of the curved portion of the blade and the pump efficiency;

Fig. 7 is a graph similar to Fig. 6, showing a graph corresponding to the relationship between the angle of the curved portion of the vane and the pump efficiency;

Fig. 8 is similar to Fig. 2, shows the second embodiment of the present invention;

Figure 9 is a further enlarged view of Figure 8;

Figure 10 is similar to Figure 4, showing the blades of the impeller;

Figure 11 is similar to Figure 5, showing a plurality of blades of the impeller;

Fig. 12 is similar to Fig. 3 and is a sectional view along line XII-XII in Fig. 11;

Fig. 13 is a graph similar to Fig. 7, showing the relationship between the inclination angle of the chamfered portion on the root side and the pump efficiency;

Fig. 14 is a graph similar to Fig. 13, showing the relationship between the length of the chamfered portion on the root side and the pump efficiency;

Fig. 15 is similar to Fig. 1, shows the third embodiment of the present invention;

Fig. 16 is similar to Fig. 8, shows the main part of Fig. 15;

Fig. 17 is similar to Fig. 12, is a sectional view along line XVII-XVII in Fig. 16;

Fig. 18 is similar to Fig. 9, shows the main part of Fig. 17;

Figure 19 is similar to Figure 10, showing a plurality of blades of the impeller;

Figure 20 is a view similar to Figure 11, showing a plurality of blades of the impeller;

Fig. 21 is similar to Fig. 17, is the sectional view along XXI-XXI line in Fig. 20;

Fig. 22 is a graph similar to Fig. 14, showing the relationship between the inclination angle of the chamfered portion on the root side and the pump efficiency;

Fig. 23 is a graph similar to Fig. 22, showing the relationship between the length of the chamfered portion on the root side and the pump efficiency;

Figure 24 is similar to Figure 18, showing a first modification of the third embodiment; and

Fig. 25 is similar to Fig. 19 and shows a second modification of the third embodiment.

Detailed ways

A turbo fuel pump embodying the present invention will be described with reference to the drawings.

Referring to Figures 1-7, a first embodiment of the present invention is shown. Referring to FIG. 1, the turbo fuel pump has a cylindrical casing 1 which constitutes the casing of the pump and has axial ends closed by a delivery cover 2 and a pump housing 9. Referring to FIG.

A capped cylinder delivery cap 2 is fitted at one end of the housing 1 . As shown in FIG. 1 , the delivery cover 2 is provided with a delivery pipe 2A and a connector 2B protruding upward, and a bearing sleeve 2C extending downward at the center.

A check valve 3 is installed in the delivery pipe 2A for maintaining residual pressure. During the rotation of the electric motor 7, the check valve 3 is opened by the fuel flowing into the housing 1, so that the fuel can be pressed from the delivery pipe 2A into an external fuel pipe (not shown). When the motor stops, the check valve 3 is closed to prevent the fuel in the fuel pipe from flowing back into the casing 1, so that a predetermined residual pressure is maintained in the fuel pipe.

Referring to FIG. 2 , the bushing 4 is fitted in the bearing sleeve 2C of the delivery cover 2 , and the bushing 5 is fitted in the stepped hole 12E of the inner casing 12 . The bushes 4, 5 constitute a bearing that rotatably supports the rotary shaft 6.

The rotary shaft 6 is supported between the delivery cover 2 and the pump housing 9 via bushings 4 , 5 . As shown in FIG. 2, the rotary shaft 6 extends axially along the axis O-O inside the casing 1 so as to rotatably support a rotor 7B of the motor 7 and the like. Referring to FIG. 3 , a chamfer 6A is machined at the lower end of the rotating shaft 6 so as to engage with the impeller 2 in a non-rotating state.

The motor 7 is housed in the housing 1 and has a cylindrical yoke 7A fitted in the housing 1 between the delivery cover 2 and the pump housing 9 for supporting a stator (not shown) with permanent magnets, a rotor 7B and a commutator 7C are mounted with a gap in the yoke 7A, and are fitted on the rotary shaft 6 to rotate therewith, and a pair of brushes (not shown) are in sliding contact with the commutator 7C.

As far as the motor 7 is concerned, when power is supplied to the rotor 7B through the connector 2B of the delivery cover 2, the brushes and the commutator 7C, the rotor 7B rotates together with the rotating shaft 6 so as to drive the impeller 20 at a medium to high rpm, i.e. Rotate within the range of 5000-8000rpm.

A fuel channel 8 is formed between the yoke 7A and the rotor 7B of the motor 7, which is used to circulate the fuel discharged from the oil outlet 14 of the pump housing 9 into the casing 1 to the delivery cover through the gap between the yoke 7A and the rotor 7B 2.

The pump housing 9 is installed at the other or lower end of the outer housing 1 , obtained by vertically adjoining the outer housing 10 and the inner housing 12 . The pump housing 9 serves to rotatably accommodate an impeller 20 .

As shown in FIGS. 1 and 2 , the outer casing 10 of the pump casing 9 is firmly fitted on the lower end of the casing 1 by a fixing means such as caulking to close the casing 1 from the outside. The outer casing 10 and the oil inlet 11 are integral.

The outer casing 10 has a circular recess 10A at the center of the shaft (axis O-O), and a circular recess 10B of substantially semicircular cross-section extending circumferentially around the axis O-O corresponding to the outer circumference of the impeller 20 . As shown in FIG. 3 , the circular groove 10B extends circumferentially within the range of the angle θ, and together with the peripheral wall groove 12D of the inner housing 12 constitutes the lower butt side channel 18

The inner housing 12 is used as housing part to form the pump housing 9 together with the outer housing 10 . The inner case 12 is fitted in the outer case 1 in a state of butting against the outer case 10 .

As shown in FIG. 2, the inner case 12 is shaped like a covered flat cylinder, and has a cylindrical portion 12A forming a cylindrical peripheral wall and a lid portion 12B covering the cylindrical portion 12A from above. The inner edge of the cylindrical portion 12A is formed with a circular impeller-accommodating recess 13 which opens on the side of the joint surface 12C of the cylindrical portion 12A and the outer casing 10 . Furthermore, the cylindrical portion 12A is formed with a peripheral wall groove 12D under the annular protrusion 16 . The peripheral wall groove 12D together with the circular groove 10B on the outer housing 10 forms a butt side channel 18 . The cover portion 12B is formed with a stepped hole 12E into which the bushing 5 is inserted, and has an oil outlet 14 extending vertically on the outer edge of the cover portion 12B.

An annular passage 15 is formed through the pump housing 9 at the outer edge of the impeller-accommodating recess 13 , extending circumferentially centered on the axis O in a substantially C-shaped manner, as shown in FIG. 3 . The fuel passage 15 has two parts, namely an inner passage 17 and a butt side passage 18 , which are vertically divided by the annular protrusion 16 .

The beginning end of the fuel passage 15 is connected with the oil inlet 11 , and the end is connected with the oil outlet 14 . In addition, the fuel passage 15 has an inlet passage portion 15A at the beginning for smoothly guiding the fuel sucked through the inlet 11 into the fuel passage 15 .

An annular protrusion 16 is formed on the cylindrical portion 12A of the inner housing 12 . As shown in FIG. 2 , the annular protrusion 16 is radially inward from the cylindrical portion 12A in the shape of a mountain range, and protrudes toward the periphery of the impeller 20 . And the next two parts, that is, the inner channel 17 and the butt side channel 18.

The inner passage 17 is a C-shaped cross-sectional groove formed at an inner corner between the cylindrical portion 2A and the cover portion 12B of the inner housing 12 . The butting-side channel 18 is a C-shaped cross-sectional groove formed by the circular groove 10B of the outer casing 10 and the outer edge wall groove 12D of the inner casing 12 .

The annular protrusion 16, together with the passages 17, 18, extends along the circumferential direction of the impeller 20 within the range of an angle θ (e.g. equal to 250-270°), as shown in FIG. Wait for it to appear.

The inner housing 12 has a sealing partition 19 on the cylindrical portion 12A side. As shown in FIG. 3 , the sealing partition 19 protrudes from the cylindrical portion 12A of the inner housing 12 to a point adjacent to the outer circumference of the impeller 20 as a circular protrusion. The sealing partition 19 seals the periphery of the impeller 20 between the oil inlet 11 and the oil outlet 14 , so that the fuel sucked through the oil inlet 11 must flow along the fuel passage 15 .

The impeller 20 is shaped, for example, approximately like a disc made of reinforced plastic material and is mounted rotatably in the impeller receiving recess 13 of the pump housing 9 . The impeller 20 is driven by the motor 7 to rotate in the direction of arrow A in FIG. 3 , and the fuel sucked through the fuel inlet 11 is sent to the fuel outlet 14 through the fuel passage 15 .

The impeller 20 has an engaging hole 21 at the center of rotation (axis O-O), and the rotating shaft 6 is fitted into this hole. A plurality of (for example, three) through holes 22 are arranged around the engagement hole 21 . Referring to FIG. 4, the impeller 20 has a plurality of radially extending blades 23 arranged in the circumferential direction on its circumference. Between adjacent vanes 23 there is a pair of circular grooves 24 each having a curvature substantially corresponding to the circular shape of the passages 17 , 18 of the pump housing 9 .

The impeller 20, together with the rotating shaft 6, is driven by the motor 11, and the upper and lower surfaces of the impeller 20 are floatingly sealed between the upper surface of the outer casing 10 and the lower surface of the cover portion 12B in the impeller receiving recess 13. Each of the through holes 22 of the impeller 20 has a function of equalizing the fuel pressure, etc., between the circular recess 10A of the outer casing 10 and the stepped hole 12E of the inner casing 12 .

Referring to Fig. 5, each blade 23 has a linear blade portion 23A that is positioned at the root side and extends linearly along the radial direction of the impeller 20, and starts from the head of the linear blade portion 23A, viewed along the direction of rotation, i.e. the arrow In the direction of A, the curved blade portion 23B extends circularly toward the front side of the impeller 20 .

Next, the shape of the blade 23 will be described in detail. As shown in FIG. 5, the length from the root position B of the straight blade portion 23A to the head position C of the curved blade portion 23B, that is, the entire length of the blade 23, is referred to as a total length H; B to the starting point position D of the curved blade portion 23B, that is, the length of the head position D of the straight blade portion 23A, is referred to as a straight portion length H1; from the starting point position D of the curved blade portion 23B to the head position D. The length of the portion position C is referred to as the bent portion length H2.

The forwardly inclined length of the curved blade portion 23B between the forwardmost position E inclined forwardly in the rotational direction and the straight blade portion 23A is shown by an angle α with reference to the rotational center (axis O-O) of the impeller 20 .

In the first embodiment, it is shown that when the straight portion length H1 of the straight blade portion 23A is set with respect to the total length H of the blade 23, that is, the starting point position D of the curved blade portion 23B according to the following formula (1), Excellent pump efficiency can be obtained:

1/3≤(H1/H)≤2/3 …(1)

In this regard, it was shown that better pump efficiency can be obtained when H1/H in the formula (1) is set within the range given by the following formula (2):

2/5≤(H1/H)≤3/5 …(2)

Furthermore, it was shown that excellent pump efficiency can be obtained when the angle α corresponding to the forwardly inclined length of the curved blade portion 23B is set according to the following formula (3):

0.5≤α≤2.0 …(3)

In this regard, it was shown that better pump efficiency can be obtained when α in formula (3) is set within the range given by the following formula (4):

1.0≤α≤1.5 ...(4)

Next, the operation of the first embodiment will be explained. When the pump is powered from the outside through the connector 2B of the delivery cover 2, the drive current delivered to the rotor 7B of the motor 7 makes the rotor 7B rotate with the rotating shaft 6, driving the impeller 20 in the pump housing 9. When the impeller 20 rotates, the fuel in the fuel tank (not shown) is sucked into the fuel passage 15 through the oil inlet 11, and then the fuel is conveyed along the fuel passage 15 by the blade 23 of the impeller 20, and is pressed to the casing through the oil outlet 14 1 in.

The fuel pressed into the housing 1 flows through the fuel passage 8 in the housing 1 to the delivery cap 2 in order to open the non-return valve 3 in the delivery line 2A. Then, the fuel is delivered from the delivery pipe 2A through an outer oil pipe (not shown), for example, at a pressure of 200-500 kPa and a flow rate of 30-200 L/h, to an injection valve (not shown) of the engine body.

As a result of our study on the ratio of the straight portion length H1 of the straight blade portion 23A to the total length H of the blade 23, it was confirmed that when the ratio H1/H is set at 1/3-2/3 shown in the formula (1), When it is in the range, preferably, when it is in the range of 2/5-3/5 shown in the formula (2), a higher pump efficiency as shown in the characteristic curve in FIG. 6 can be obtained. In this case, the angle α corresponding to the forwardly inclined length of the curved blade portion 23B is set at about 1.2°.

Furthermore, as a result of our studies on the angle α corresponding to the forwardly inclined length of the curved blade portion 23B, it was confirmed that when the angle α is set within the range of 0.5-2.0° shown in the formula (3), it is best, When it is in the range of 1.0-1.5° as shown in the formula (4), a higher pump efficiency as shown in the characteristic curve of FIG. 7 can be obtained. In this case, the ratio of the straight portion length H1 of the straight blade portion 23A to the total length H of the blade 23 is set at approximately 1/2.

In this regard, it is shown that when the ratio of the straight portion length H1 of the straight blade portion 23A to the total length H of the blade 23 is set at about 1/2 in the range of 2/5-3/5, while the corresponding curved blade portion The angle α of the forwardly inclined length of 23B is set at about 1.2° in the range of 1.0-1.5°, enabling the highest pump efficiency.

Therefore, in the first embodiment, the starting point position D at which the curved portion 23B of the blade 23 of the impeller 20 starts to bend, that is, the straight portion length H1, is set at 2/5- 3/5 (approximately 1/2) position while the angle α corresponding to the forwardly inclined length of the curved blade portion 23B is set at 1.0-1.5° (approximately 1.2°).

This enables the blade 23 to have a curved blade portion 23B that is gently curved from the middle in the length direction and has an appropriate forward inclination length obtained in the rotation direction of the impeller 20 .

As a result, when the impeller 20 rotates, smooth fuel flow from the vane grooves between the vanes 23 to the fuel passage 15 can be obtained even in a relatively low flow velocity range, preventing a decrease in flow velocity with respect to rpm. In addition, the impeller 20 provides suitable kinetic energy to the fuel, can prevent the increase of torque loss in a relatively large flow rate range, and can make the pump operate in the high efficiency range of the electric motor 7, resulting in a higher efficiency in the entire operating range of the pump. High pump efficiency.

In addition, since the curved vane portion 23B of the vane 23 is formed with a circular bend, the fuel can flow smoothly along the circular surface of the curved vane portion 23B, enabling the fuel to flow smoothly from the vane groove between the vanes 23 .

Referring to FIGS. 8-14 , a second embodiment of the present invention is shown here, except that the angle between the side and the rear side of the blade 35 located at the blade 35 root side is obliquely cut off, and the inverted blade extending radially along the impeller 20 is removed. Except for angle 39, the construction of the second embodiment is basically the same as that of the first embodiment.

8 and 9, the annular fuel passage 31 is located at the position of the fuel passage 15 of the first embodiment. The fuel channel 31 includes the circular groove 10B of the outer shell 10, forming a channel with a C-shaped cross-section and a relatively large vertical length extending circumferentially around the axis O-O.

The fuel passage 31 has circular upper and lower ends, along which the fuel flows in the form of a circular flow as shown by the arrows in Figure 9, so that when the fuel is delivered through the fuel passage 31, the center of the circular part of the fuel passage 31 The circumference forms the channel center F. The passage center F is located at a distance L1 of about 1/2 from the inner end 31A with respect to the radial length L from the inner end 31A to the outer end 31B of the fuel passage 31 . The beginning of the fuel passage 31 is connected to the fuel inlet 11 , and the end is connected to the fuel outlet 14 .

The impeller 32 is shaped, for example, substantially like a disc made of reinforced plastic material and is rotatably mounted in the impeller receiving recess 13 of the pump housing 9 .

The impeller 32 has an engaging hole 33 in which the rotating shaft 6 is fitted at the center of rotation (axis O-O). A plurality of (for example, three) through holes 34 are arranged around the engagement hole 33 . Referring to Fig. 10, the impeller 20 has a plurality of blades 35 arranged in the circumference and extending in the radial direction at its periphery. A pair of circular grooves 36 are located between adjacent vanes 35 in the form of a mountain, each groove 36 having a curvature substantially corresponding to the circular shape of the fuel passage 31 of the pump housing 9 .

Referring to Figures 10 and 11, the blade 35 is shaped as a plate body with a substantially rectangular cross-section, and has a front face 35A on the front side as viewed in the direction of rotation of the impeller 32, ie, the direction of arrow A, and a front 35A located on the rear side as viewed in the direction of rotation. A rear face 35B on one side, and a pair of side faces 35C located between the front face 35A and the rear face 35B.

The blade 35 has, on the root side, a straight blade portion 37 extending linearly in the radial direction of the impeller 32, and on the head side, a curved blade portion 38 that is circularly curved on the front side as viewed in the direction of rotation of the impeller 32. The shape and size of the vane portions 37, 38 are set according to formulas (1) and (3), preferably, formulas (2) and (4) described above with respect to the first embodiment.

A pair of chamfers 39 are located on the root side of the blade 35 and extend along the radial direction of the impeller 32 . 10-12, each chamfer 39 is obtained by obliquely cutting off the corner between the side 35C and the rear 35B of the blade 35. Referring to FIGS. The total length T of the chamfer 39 is set approximately equal to the distance L1 from the inner end 31A of the fuel passage 31 to the passage center F, that is, a value of (2/5 to 3/5)×L, where L is the fuel passage 31 The radial length of , according to the following formula (5):

2/5≤(T/L)≤3/5 …(5)

The total length T of the chamfer 39 is preferably set to a value of (9/20 to 11/20)×L according to the following formula (6):

9/20≤(T/L)≤11/20 …(6)

The total length T of the chamfer 39 is set within the range given by equations (5) and (6), preferably, at a value of 1/2 relative to the radial length L of the fuel passage 31 . Thereby, the chamfer 39 is configured to extend to the channel center F formed when the fuel flows through the fuel channel 31 in a circular flow, so as to achieve the best effect of fuel smoothly flowing into the vane grooves between the vanes 35 .

The chamfer 39 has a substantially rectangular root-side chamfer portion 39A that is located on the root side and has a substantially constant chamfer width, and has a chamfer width that gradually decreases from the root-side chamfer portion 39A. The substantially triangular head-side chamfered portion 39B.

The chamfered portion 39A on the root side is formed by cutting off a corner to have a constant chamfer width to obtain a smooth flow of fuel flowing into the blade grooves between the blades 36 from the root side thereof, which can reduce the fuel flow. flow resistance. On the other hand, the chamfered portion 39B on the head side is formed with a gradually decreasing chamfer width toward the head thereof, achieving smoothness between the rear face 35B and the side face 35C of the blade 35 and the chamfered portion 39A on the root side. connection so that fuel can flow smoothly through it.

Referring to FIG. 12, the shape of the chamfered portion 39A on the root side of the chamfer 39 will be described in detail. The inclination angle β of the chamfered portion 39A on the root side with respect to the side surface 35C of the blade 35 is set in the range of 30-70° according to the following formula (7):

30≤β≤70 …(7)

The inclination angle β in the formula (7) is preferably set in the range of 40-60° according to the following formula (8):

40≤β≤60 ...(8)

9, the length T1 of the chamfered portion 39A on the root side is set to a value of (1/5 to 4/5)×T with respect to the total length T of the chamfer 39 according to the following formula (9):

1/5≤(T1/T)≤4/5 …(9)

The length T1 of the chamfered portion 39A on the root side is preferably set to a value of (2/5-3/5) according to the following formula (10):

2/5≤(T1/T)≤3/5 …(10)

As a result of research on the inclination angle β of the chamfered portion 39A on the root side with respect to the side surface 35C of the blade 35, it was confirmed that when the inclination angle β is set within the range of 30-70° as shown in the formula (7), the most Well, in the range of 40-60° as shown in formula (8), higher pump efficiency as shown in the characteristic curve in FIG. 13 can be obtained.

In this case, the ratio of the length T1 of the chamfered portion 39A on the root side to the total length T of the chamfer 39 is set at about 1/2. Thereby, the inclination angle β of the chamfered portion 39A on the root side can be set substantially equal to the flow angle of the fuel flowing from the side face 35C of the blade 35 to the rear face 35B thereof, resulting in the formation of the chamfer along the root side. Smooth fuel flow for part 39A.

Furthermore, as a result of studies on the ratio of the length T1 of the chamfered portion 39A on the root side to the total length T of the chamfer 39, it was confirmed that when the ratio T1/T is set at 1/5- In the range of 4/5, preferably, in the range of 2/5-3/5 as shown in formula (10), a higher pump efficiency as shown in the characteristic curve in FIG. 14 can be obtained.

In this case, the angle of inclination β of the chamfered portion 39A on the root side with respect to the side face 35C of the blade 35 is set at approximately 50°. Thereby, the chamfered portion 39A on the root side suppresses a vortex that may be generated on the root side of the vane 35 by the large groove of constant width, allowing the fuel to flow in smoothly.

In addition, our research has shown that since the chamfered portion 39B on the head side has a chamfered width that gradually decreases toward the head, the gap between the rear face 35B and the side 35C of the blade 35 and the chamfered portion 39A on the root side is guaranteed With the smooth connection, the fuel can smoothly flow from the side 35C of the vane 35 to the chamfered portion 39A on the root side, and from the chamfered portion 39A on the root side to the rear 35B, so that a higher pump efficiency can be obtained.

In this regard, it is shown that when the ratio T/L of the total length T of the chamfer 39 to the radial length L of the fuel passage 31 is set at 1/2 in the range of 9/20-11/20, the root side The inclination angle β of the chamfered portion 39A with respect to the side surface 35C of the blade 35 is set at 50° in the range of 40-60°, and the length T1 of the chamfered portion 39A on the root side is equal to the total length T of the chamfered portion 39. When the ratio T1/T is set at 1/2 within the range of 2/5-3/5, the highest pump efficiency can be obtained.

In the second embodiment, a chamfer 39 obtained by obliquely cutting off the corner between the side surface 35C and the rear surface 35B is located on the side surface of the impeller 32 . Therefore, when the impeller 32 rotates, the chamfer 39 allows the fuel to flow smoothly along the chamfered portion 39A on the root side and the chamfered portion 39B on the head side.

In addition, the chamfer 39 is designed in such a way that the ratio of the total length T extending radially of the impeller 32 to the radial length L of the fuel passage 31 is set to 9/20-11/20 (preferably 1/2) , the angle of inclination β of the chamfered portion 39A on the root side with respect to the side face 35C of the blade 35 is set to 40-60° (preferably 50°), and the length T1 of the chamfered portion 39A on the root side is the same as that of the chamfered angle 39 The ratio of the total length T is set to 2/5-3/5 (preferably 1/2).

Thus, in the second embodiment, the position and length of the chamfer 39 (the chamfered portion 39A on the root side) and the inclination angle of the chamfer 39A on the root side can correspond to the point where the fuel flows into the vane 35 through the fuel passage 31. The inflow position of the vane groove between the blades is set, the size is according to the needs of smooth inflow, and the angle enables smooth inflow, so that it can flow from the vane groove between the vanes 35 to the fuel passage more smoothly compared with the first embodiment 31, able to achieve higher pump efficiency.

Referring to Figures 15-23, a third embodiment of the present invention is shown. Referring to FIG. 15, the turbo fuel pump has a cylindrical housing 101 which constitutes the pump casing and has axial ends closed by a delivery cover 102 and a pump housing 109. Referring to FIG.

A cylindrical delivery cover 102 with a cover is located at one end of the housing 101 . As shown in FIG. 15 , the delivery cover 102 is provided with a delivery tube 102A and a connector 102B protruding upward, and a bearing sleeve 102C extending downward at the center.

A check valve 103 is provided in the delivery pipe 102A for maintaining residual pressure. When the motor 107 is rotated, the check valve 103 is opened by the fuel flowing into the housing 101 to deliver the fuel from the delivery pipe 102A to an external fuel pipe (not shown). When the motor 107 is stopped, the check valve 103 is closed to prevent the fuel in the fuel pipe from flowing back into the casing 101, thereby maintaining the fuel pipe at a predetermined residual pressure.

Referring to FIG. 16 , the bushing 104 is installed in the bearing housing 102C of the delivery cover 102 , and the bushing 105 is installed in the stepped hole 112D of the inner casing 112 . The bushings 104, 105 constitute a bearing that rotatably supports the rotary shaft 106. As shown in FIG.

The rotary shaft 106 is supported between the delivery cover 102 and the pump housing 109 via bushings 104 , 105 . As shown in FIG. 16, the rotary shaft 106 extends axially along the axis O-O inside the casing 101 to rotatably support the rotor 107B of the motor 107 and the like. Referring to Fig. 17, a flat surface (chamfer) 106A is formed at the lower end of the rotating shaft 106 so as to engage with the impeller 117 in a non-rotating state.

The motor 107 is housed in the casing 101, and has a cylindrical yoke 107A fitted inside the casing 101 between the delivery cover 102 and the pump housing 109 for supporting a stator (not shown) made of permanent magnets. , the rotor 107B and the commutator 107C are installed in the yoke 107A with a gap between the yoke 107A, the rotor 107B and the commutator 107C are assembled on the rotating shaft 106 so as to rotate integrally together, a pair of brushes (not shown) and the commutator 107C is in sliding contact.

For the motor 107, when the rotor 107B is powered by the connector 102B, the brush and the commutator 107C of the delivery cover 102, the rotor 107B rotates together with the rotating shaft 106 to drive the impeller 117, for example, at 5000-8000rpm.

A fuel passage 108 is formed between the yoke 107A and the rotor 107B of the electric motor 107 for passing the fuel pressed from the oil outlet 114 of the pump housing 101 to the casing 101 to the delivery cover 102 through the gap between the yoke 107A and the rotor 107B. .

The pump housing 109 is provided at the other or lower end of the outer housing 101 and is obtained by vertically adjoining the outer housing 110 and the inner housing 112 . The pump housing 109 serves to rotatably accommodate an impeller 117 .

As shown in FIGS. 15 and 16 , the outer casing 110 of the pump casing 109 is snap-fitted on the lower end of the casing 101 by a fixing means such as calking to close the casing 101 from the outside. The outer shell 110 and the oil inlet 111 form an integral body.

The outer casing 110 has a circular recess 110A formed at the center of the shaft (axis O-O), and a circular recess 10B formed of a substantially semicircular section corresponding to the periphery of the impeller 117 and extending circumferentially around the axis O-O. .

The inner housing 112 is located on the outer housing 110 and assembled in the outer housing 101 in a state of being docked on the outer housing 110 . As shown in FIG. 16, the inner housing 112 is shaped like a flat cylinder with a cover, and has a cylindrical portion 112A forming a cylindrical peripheral wall and a cover covering the cylindrical portion 112A from above. Section 112B. The cylindrical portion 112A has an impeller-accommodating circular recess 113 on its inner peripheral surface, which is open on the side of the joint surface 112C of the cylindrical portion 112A and the outer casing 110 .

In addition, the cylindrical portion 112A has an annular fuel passage 115 on its inner surface. The cover portion 112B is formed with a stepped hole 112D into which the bushing 105 is inserted, and has a vertically extending oil outlet 114 at the outer edge.

A fuel passage 115 is formed through the pump housing 109 at the outer edge of the recess 113 for accommodating the impeller. The fuel passage 115 extends around the axis O in a substantially C shape, as shown in FIGS. 16 and 18 . The fuel passage 115 includes a circular groove 110B of the outer housing 110 .

The fuel passage 115 has circular upper and lower ends along which the fuel flows in a circular flow as shown in FIG. Form the channel center C. The passage center C is located at a distance of about 1/2L1 from the inner end 115A with respect to the radial length L from the inner end 115A of the fuel passage 115 to the outer end 115B thereof.

The fuel passage 115 has a beginning connected to the fuel inlet 111 and a terminal connected to the fuel outlet 114 . Further, the fuel passage 115 has an inlet passage portion 115C on the start side for smoothly introducing the fuel sucked through the inlet 111 into the fuel passage 115 .

The sealing partition 116 is provided on the cylindrical portion 112A side of the inner housing 112 . As shown in FIG. 17 , the seal partition 116 is formed as a circular protrusion protruding from the cylindrical portion 112A of the inner housing 112 to a point adjacent to the outer circumference of the impeller 117 . The sealing partition 116 seals the periphery of the impeller 117 between the oil inlet 111 and the oil outlet 114 , so that the fuel sucked through the oil inlet 111 must flow along the fuel passage 115 .

The impeller 117 is shaped, for example, substantially like a circular disk of reinforced plastic material, and is rotatably mounted in an impeller-accommodating recess 113 of the pump housing 109 . The impeller 117 is driven by the motor 107 to rotate in the direction of arrow A in FIG. 17 , and delivers the fuel sucked through the fuel inlet 111 to the fuel outlet 114 through the fuel passage 115 .

The impeller 117 has an engaging hole 118 in which the rotating shaft 106 is fitted at the center of rotation (axis O-O). A plurality of (for example, three) through holes 119 are arranged around the engagement hole 118 . Referring to Fig. 19, the impeller 117 has a plurality of radially extending blades 120 arranged in the circumferential direction on its periphery. A pair of circular grooves 121 are located between adjacent vanes 120 , each groove 121 having a curvature generally corresponding to the circular shape of the channel 115 of the pump housing 109 .

The impeller 117, together with the rotating shaft 106, driven by the motor 107, is floatingly sealed between the upper surface of the outer casing 110 and the lower surface of the cover portion 112B in the impeller-accommodating recess 13 above and below the impeller 117. Each through hole 119 of the impeller 117 has a function of equalizing the fuel pressure between the circular recess 110A of the outer casing 110 and the stepped hole 112D of the inner casing 112 .

Referring to Figures 19 and 20, the blade 120 is formed as a plate with a substantially rectangular cross-section. A rear face 120B on one side, and a pair of side faces 120C between the front face 120A and the rear face 120B.

The blade 120 has a straight blade portion 122 on the root side extending linearly in the radial direction of the impeller 117, and a curved blade portion 123 on the head side that is circularly curved on the front side toward the rotation direction of the impeller 117 as shown. The straight blade portion 122 and the curved blade portion 123 are about half the total length of the blade 120 .

A pair of chamfers 124 are located at the root side of the blade 120 and extend along the radial direction of the impeller 117 . Referring to FIGS. 19-21 , each chamfer 124 is obtained by obliquely cutting off the corner between the side 120C and the rear 120B of the blade 120 . The total length H of the chamfer 124 is set approximately equal to the distance L1 from the inner end 115A of the fuel passage 115 to the passage center C thereof, that is, a value of (2/5−3/5)×L, where L is the fuel passage The radial length of 31, according to the following formula (11):

2/5≤(T/L)≤3/5 …(11)

The total length H of the chamfer 124 is preferably set to a value of (9/20-11/20)×L according to the following formula (12):

9/20≤(T/L)≤11/20 …(12)

The total length H of the chamfer 124 is set within the range given by equations (11) and (12), preferably, at a value of 1/2 relative to the radial length L of the fuel passage 115 . Thus, the chamfer 124 is configured to extend to the channel center C formed when the fuel flows through the fuel channel 115 in a circular flow, so that the best effect of fuel flowing smoothly into the vane grooves between the vanes 120 can be achieved.

The chamfer 124 has a substantially rectangular root-side chamfer portion 124A located on the root side and having a substantially constant chamfer width, and a substantially rectangular chamfer width gradually decreasing from the root-side chamfer portion 124A. The chamfered portion 124B on the head side of the triangle.

The chamfered portion 124A on the root side is formed by cutting off a corner and has a substantially constant chamfer width to obtain a smooth fuel flow from the root side thereof into the blade grooves between the blades 120, making it possible to reduce Resistance to fuel flow. On the other hand, the chamfered portion 124B on the head side constitutes a chamfered width gradually decreasing toward the head thereof, realizing a smooth connection between the rear face 120B and the side face 120C and the chamfered portion 124A on the root side, so that Fuel flows smoothly through it.

Referring to FIG. 21, the shape of the chamfered portion 124A on the root side of the chamfer 124 will be described in detail. The inclination angle α of the chamfered portion 124A on the root side with respect to the side surface 120C of the blade 120 is set in the range of 30-70° according to the following formula (13):

30≤α≤70 …(13)

The inclination angle α in the formula (7) is preferably set within the range of 40-60° according to the following formula (8):

40≤α≤60 …(14)

18, the length H1 of the chamfered portion 124A on the root side is set at the value of (1/5≤4/5)×T with respect to the total length H of the chamfer 124 according to the following formula (15):

1/5≤(H1/H)≤4/5 …(15)

The length H1 of the chamfered portion 124A on the root side is preferably set to a value of (2/5-3/5)×H according to the following formula (16):

2/5≤(H1/H)≤3/5 …(16)

Next, the operation of the third embodiment will be explained. When the pump is powered from the outside through the connector 102B of the delivery cover 102 , the drive current delivered to the rotor 107B of the motor 107 makes the rotor 107B rotate together with the rotating shaft 106 to drive the impeller 117 in the pump housing 109 . When the impeller 117 rotates, the fuel in the fuel tank (not shown) is sucked into the fuel passage 115 through the oil inlet 111, then the fuel is conveyed along the fuel passage 115 by the blade 120 of the impeller 117, and is pressed to the casing through the oil outlet 114 101 in.

The fuel pressed into the casing 101 flows through the fuel passage 108 and the like in the casing 1 to the fuel outlet 102 to open the check valve 103 in the delivery pipe 102A. Then, the fuel is delivered from the delivery pipe 102A through an external delivery pipe (not shown), for example, at a pressure of 200-500 kPa and a delivery rate of 30-200 L/h, to an injection valve (not shown) of the engine body.

As a result of our research on the angle α of the chamfered portion 124A on the root side with respect to the side surface 120C of the blade 120, it was confirmed that when the angle α is set within the range of 30-70° shown in formula (13), it is best , within the range of 40-60° shown in formula (14), higher pump efficiency shown by the characteristic curve in Figure 22 can be obtained under the conditions of 300kPa delivery pressure and 80L/h delivery speed.

In this case, the ratio of the length H1 of the chamfered portion 124A on the root side to the total length H of the chamfer 124 is set at approximately 1/2. Thereby, the inclination angle α of the chamfered portion 124A on the root side can be set to be substantially equal to the flow angle of the fuel flowing from the side surface 120C of the blade 120 to the rear surface 120B thereof, so that the fuel oil flows along the chamfered portion 124A on the root side. Flows smoothly, resulting in reduced resistance to fuel flow.

Furthermore, as a result of our study on the ratio of the length H1 of the chamfered portion 124A on the root side to the total length H of the chamfer 124, it was confirmed that when the ratio H1/H is set at 1/5- In the range of 4/5, preferably, in the range of 2/5-3/5 shown in formula (16), a higher pump efficiency as shown in the characteristic curve in FIG. 23 can be obtained.

In this case, the angle of inclination α of the chamfered portion 124A on the root side with respect to the side face 120C of the blade 120 is set to about 50°. In this way, the chamfered portion 124A on the root side restrains the vortex that may appear on the root side of the blade 120 through the large groove of constant width, which can reduce the resistance of fuel flow.

In addition, our research has shown that since the chamfered portion 124B on the head side has a chamfered width that gradually decreases toward the head, it ensures Due to the smooth connection between them, the fuel can smoothly flow from the side 120C of the blade 120 to the chamfered portion 120A on the root side and from the chamfered portion 120A on the root side to the rear 120B, so that higher pump efficiency can be obtained.

In this regard, it is shown that when the ratio H/L of the total length H of the chamfer 124 to the radial length L of the fuel passage 115 is set at 1/2 in the range of 9/20-11/20, the root side The inclination angle α of the chamfered portion 124A with respect to the side surface 120C of the blade 120 is set at 50° in the range of 40-60°, and the length H1 of the chamfered portion 124A on the root side is equal to the total length H of the chamfered portion 124. When the ratio H1/H is set at 1/2 within the range of 2/5-3/5, the highest pump efficiency can be obtained.

In the third embodiment, a chamfer 124 obtained by obliquely cutting off the corner between the side surface 120C and the rear surface 120B is located on the side surface of the impeller 117 . Design the chamfer 124 like this, promptly the ratio of the total length H extending radially at the impeller 117 and the radial length L of the fuel passage 115 is set to 9/20-11/20 (preferably 1/2), root one The angle of inclination α of the chamfered portion 124A of the side relative to the side surface 120C of the blade 120 is set to 40-60° (preferably 50°), and the length H1 of the chamfered portion 124A on one side of the root and the total length of the chamfered angle 124 The ratio of H is set to 2/5-3/5 (preferably 1/2).

Thus, in the third embodiment, the position and length of the chamfer 124 (the chamfered portion 124A on the root side) and the inclination angle of the chamfered portion 124A on the root side can correspond to the flow of fuel into the vane 120 through the fuel passage 115 The inflow position of the blade groove between is set, the size is according to the need of smooth inflow, and the angle enables smooth inflow.

As a result, when the impeller 117 rotates, the chamfer 124 enables the fuel to flow smoothly along the chamfered portion 124A on the root side and the chamfered portion 124B on the head side, so as to reduce the fuel flow resistance and realize the passage of fuel through the fuel passage. 115 is efficiently output to the oil outlet 114, resulting in an increase in pump efficiency.

In the third embodiment, the fuel passage 115 is shaped as a passage with a large vertical length and a C-shaped cross-section. Preferably, referring to Fig. 24, in a first modification, the fuel passage 131 may be divided into two parts vertically by an annular protrusion 132 protruding radially inward from the center 133 of the fuel passage, namely the inner passage 133 and the butt joint. Side channel 134 is formed.

Furthermore, in the third embodiment, each blade 120 has a linear blade portion 122 extending linearly in the radial direction of the impeller 117 on the root side, and has a circular blade portion 122 viewed from the front side in the direction of rotation of the impeller 117 on the head side. The curved blade portion 123 is curved in shape. Alternatively, referring to Fig. 25, in a second variation, each blade 141 may have a linear structure extending linearly from the root to the head. Alternatively, the blade 120 may have a curved configuration that is circularly curved forward in the direction of rotation from the root to the tip.

After the present invention has been described according to the intuitive embodiments, it should be pointed out that the present invention is not limited thereto, and various changes and improvements can be made without departing from the scope of the present invention.

The entire teachings of Japanese Patent Application P2002-257988 filed on September 3, 2002 and Japanese Patent Application P2002-165946 filed on June 6, 2002 are hereby incorporated by reference.

Claims (8)

1. A turbo fuel pump having: housing housing the motor; a casing mounted on the casing, the casing having an annular passage between the oil inlet and the oil outlet; and An impeller rotatably installed in the housing, which has a plurality of blades arranged on the outer circumference and extending radially along the impeller, and when the blades are rotated by the motor, fuel is delivered through the channel; Each blade has a plate body of generally rectangular cross-section, the plate body has a front face and a rear face as viewed from the direction of rotation of the impeller, and a pair of sides located between the front face and the rear face; Each blade has a chamfer extending radially along the impeller on one side of the blade root. This chamfer is obtained by obliquely cutting off the angle between the side and the rear of the blade. The chamfer has a predetermined length. The length of is (2/5 to 3/5) x L, where L is the radial length of the channel. 2. The turbo fuel pump according to claim 1, wherein the predetermined length of the chamfer is (9/20 to 11/20)×L. 3. The turbo fuel pump according to claim 1, wherein the chamfer comprises a root side portion and a head side portion, the root side portion has substantially constant chamfer width and predetermined length, and the head portion The side part has a chamfer width that gradually decreases from the head of the side part at the root. 4. The turbo fuel pump according to claim 3, wherein the predetermined length of the root side portion is (1/5 to 4/5) x T, where T is the total length of the chamfer. 5. The turbo fuel pump according to claim 4, wherein the predetermined length of the root side portion is (2/5 to 3/5)*T. 6. The turbo fuel pump according to claim 5, wherein the root side portion has a predetermined inclination angle with respect to the blade side, wherein the predetermined inclination angle is 30° to 70°. 7. The turbo fuel pump according to claim 6, wherein the predetermined inclination angle of the root side portion is 40[deg.] to 60[deg.]. 8. The turbo fuel pump according to claim 7, characterized in that, the predetermined length of the chamfer is (1/2)×L, the predetermined length of the part on one side of the root is (1/2)×T, and the one side of the root is The predetermined inclination angle of the section is 50°.

Images