JPH0794833B2 - Turbine fuel pump - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a turbine-type fuel pump that is preferably used for feeding the fuel in a fuel tank under pressure to an internal combustion engine for automobiles, for example.

[Conventional technology]

While a roller vane type fuel pump is used as a fuel pump used in an automobile internal combustion engine, a turbine type fuel pump has recently come to be used as a non-volumetric pump.

As such a turbine type fuel pump, the present applicant has previously proposed one having a structure shown in Japanese Utility Model Application No. 61-15852 (Japanese Utility Model Application No. 62-128188) (hereinafter referred to as "prior art").

Therefore, FIGS. 3 and 4 show a turbine type fuel pump of the prior art.

In the figure, reference numeral 1 denotes a casing, which is a tubular casing body 2, a pump housing 3 provided at a lower end side of the casing body 2, and an upper cover 4 provided at an upper end side of the casing body 2. The upper cover 4 and the pump housing 3 cover the upper and lower ends of the casing body 2. Here, the pump housing 3 includes an outer housing 5 formed in a substantially bottomed cylindrical shape, and a substantially disc-shaped inner housing 6 abutting on the outer housing 5, and the center of the inner housing 6 is formed. A through hole 6A is formed in the portion. Further, a boss portion of the turbine 11 to be described later is provided at the center of the bottom side of the outer housing 5.
A recess 5A is provided correspondingly to the recess 11A, and a shaft hole 5B extending axially downward from the center of the recess 5A and into which a lower end side of a fixed shaft 10 described later is fitted is provided.

Reference numeral 7 denotes a pump chamber located inside the pump housing 3 and provided between the outer housing 5 and the inner housing 6, and the outer peripheral side of the pump chamber 7 is provided with blades 11B and 11C of a turbine 11 to be described later. A fuel flow path 7A is formed so as to surround the periphery, and the cross section of the fuel flow path 7A has a substantially rectangular shape. The start end side of the fuel flow path 7A communicates with the fuel suction port 8 formed on the outer peripheral side of the bottom portion of the outer housing 5, and the end side communicates with the discharge port 9 formed on the outer peripheral side of the inner housing 6. The fuel flow path 7A extends in the circumferential direction of the pump chamber 7 over an angular range of, for example, about 300 degrees. In addition, on the upper surface of the bottom of the outer housing 5 and the lower surface of the inner housing 6, sliding surfaces 5C and 6B located on the inner side in the radial direction of the fuel passage 7A and facing the upper and lower surfaces of the turbine 11 are flat. Is formed in.

Reference numeral 10 denotes a fixed shaft that extends in the casing 1 in the axial direction. The fixed shaft 10 has an upper end side fitted into a central portion of the upper cover 4, and a lower end side thereof having an inner housing 6
It is fitted into the shaft hole 5B of the outer housing 5 through the through hole 6A. Reference numeral 11 denotes a closed vane type turbine which is located in the pump chamber 7 between the outer housing 5 and the inner housing 6 and is rotatably mounted on the lower end side of the fixed shaft 10 via a bearing 12. 11 is made of a reinforced plastic material such as 40% glass material, 40% phenol resin, 20% binder, etc., and is formed as a substantially disk-shaped body whose upper and lower surfaces are parallel to each other. It is set up.

Further, the outer peripheral side of the turbine 11 extends into the fuel passage 7A,
In addition, a large number of blades 11B,
, 11C, 11C, ... Are arranged in a row with their phases shifted from each other (see FIG. 4). Then, on the central side of the turbine 11, there are four engaging holes 11D, 11 located around the bearing 12, for example.
D, ... Are bored, the projections 21A of the joint 21 described later are engaged with the engagement holes 11D, and the turbine 11 is connected to the joint 2
Along with 1, they are driven to rotate by an electric motor 13 described later. Although omitted in FIG. 3,
Both upper and lower surfaces of the turbine 11 and sliding surfaces 5 of the housings 5 and 6
A minute gap of about 10 to 30 μm is usually provided between C and 6B, and an oil film formed in this gap provides a floating seal.

Reference numeral 13 denotes an electric motor as a motor provided in the casing main body 2. The electric motor 13 includes a rotor 16 rotatably attached to a fixed shaft 10 via bearings 14 and 14 and a sleeve 15, and the rotation of the rotor 16. A coil 17 having a plurality of poles wound around the child 16, and a casing body 2 located around the coil 17
The stator 18 fixed to the rotor 16 and the rotor 16 are integrally provided,
Commutator 19 with a commutator element with the same number of poles as the coil 17
And a pair of brushes 20, 20 that are fixed to the casing body 2 and are in sliding contact with the commutator 19. Also, the lower end of the rotor 16 has a downwardly projecting portion 16
A is provided, and the projecting portion 16A is adapted to engage with a joint 21 described later.

Reference numeral 21 denotes a joint which is located in the through hole 6A of the inner housing 6 and is rotatably disposed on the fixed shaft 10. The protrusion 16A of the rotor 16 is engaged with the upper end of the joint 21. On its lower end side, a plurality of protrusions 21A that engage with the respective engagement holes 11D of the turbine 11 are provided so as to protrude downward. And
The joint 21 is rotationally driven together with the turbine 11 by the electric motor 13, and the fuel sucked into the fuel flow path 7A from the suction port 8 by the rotation of the turbine 11 is projected from the discharge port 9 to move inside the casing main body 3 It is fed in the direction of the arrow shown in the figure.

Reference numeral 22 denotes a discharge port provided in the upper cover 4, and the discharge port 22 is connected to a fuel injection valve (neither is shown) via a discharge pipe or the like, and the fuel in the casing 1 is fed to this fuel injection valve. It is designed to be discharged. Further, a check valve 23 for retaining the residual pressure is provided in the discharge port 22,
The check valve 23 is adapted to maintain a predetermined residual pressure inside the discharge pipe when the electric motor 13 is stopped. Further, 24 indicates a relief port provided on the upper cover 4,
A relief valve 25 is provided in the relief port 24 to relieve excess pressure in the casing 1 to the outside.

In the fuel pump configured as described above, the casing 1 is immersed in the fuel in the fuel tank (not shown) to be used as the medium-oil pump. Then, when the fuel in the fuel tank is pressure-fed and supplied to the fuel injection valve, power is externally supplied to the coil 17 of the electric motor 13 via the brush 20, the commutator 19, etc., and the turbine is rotated by the rotor 16 via the joint 21. 11 is driven to rotate, the fuel in the fuel tank is sucked into the fuel flow path 7A from the suction port 8, is discharged from the discharge port 9 while being pumped in the fuel flow path 7A, and the discharge port 22 is discharged from the inside of the casing body 2. Through the discharge pipe.

In this case, between the sliding surfaces 5C and 6B of the pump housing 3 and the upper and lower surfaces of the turbine 11, a small gap of about 10 to 30 μm is interposed, and an oil film is formed in this gap. Floating seal, fuel flow path
The fuel on the discharge port 9 side of 7A is prevented from leaking to the suction port 8 side, etc. through the space between the sliding surfaces 5C, 6B and the turbine 11, etc.
It is designed to prevent deterioration of pump performance.

[Problems to be solved by the invention]

By the way, alcohol-blended gasoline has recently been used as a fuel in North American markets such as Canada and Alaska. Then, when using this kind of gasoline as a fuel, since the turbine 11 is formed of a reinforced plastic such as a phenol resin, the turbine 11 swells,
The turbine 11 may be deformed, and particularly, the deformation is remarkable on the central side of the turbine 11.

Therefore, in the above-mentioned prior art, the turbine 11 is deformed so that the upper and lower surface central portions of the turbine 11 come into frictional contact with the sliding surfaces 5C and 6B of the pump housing 3, and the upper and lower surfaces of the turbine 11 are contacted. As shown in FIG. 4, not only are wear marks 26 left on the central portion side, but also the rotational speed of the turbine 11 is reduced due to frictional resistance and the like, and the discharge flow rate is greatly reduced. .

The present invention has been made in view of the above-mentioned problems of the prior art, and the present invention can prevent frictional contact with the pump housing even when the turbine is deformed due to swelling or the like, and can solve problems such as a decrease in discharge flow rate. The turbine type fuel pump is provided.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides a pump housing provided on one side of a casing body, and a fuel flow path formed on the outer peripheral side from the suction port to the discharge port on the outer peripheral side. And a plurality of blades for pumping the fuel in the fuel flow passage are formed on the outer peripheral side of the pump chamber, which is rotatably arranged in the pump chamber and has a parallel disk-shaped lower surface. The present invention is applied to a turbine type fuel pump including a resin turbine and a motor provided in the casing body for rotationally driving the turbine.

The feature of the configuration adopted by the present invention is that the upper and lower surfaces of the turbine are located on the upper and lower surfaces of the pump chamber of the pump housing radially inward of the groove bottoms of the blades formed on the outer peripheral side of the turbine. And a ring-shaped seal portion that gives a minute gap between the turbine and the contact escape portion that is located on the inner side in the radial direction of the seal portion and that gives a gap larger than the minute gap between the upper and lower surfaces of the turbine. , The relevant escape section,
The gap between the upper and lower surfaces of the turbine is formed to be gradually smaller from the inner peripheral portion toward the outer peripheral portion on the seal portion side, and the seal portion is parallel to the upper and lower surfaces of the turbine, The width dimension in the radial direction is narrower than that of the hit escape portion.

[Action]

With the above configuration, when alcohol-blended gasoline or the like is used as the fuel and the turbine swells so as to be deformed to a greater extent on the central portion (inner circumference) side, the upper and lower sides of the turbine are on the pump chamber and the lower surface of the pump housing. Since the contact relief portion is formed so that the gap between the lower surface and the inner peripheral portion gradually decreases from the inner peripheral portion to the outer peripheral portion, a gap can be secured between the pump chamber and the lower surface even when the turbine is swollen. In addition to reliably preventing the turbine from frictionally contacting the pump housing, the contact relief portion has a gap between the upper and lower surfaces of the turbine that gradually decreases toward the outer peripheral portion, so at least the outer peripheral portion It can exert a sealing action on the side.

Further, on the upper and lower surfaces of the pump chamber of the pump housing, a ring located radially inward of the groove bottom of each blade on the outer peripheral side of the contact escape portion and providing a minute gap between the upper and lower surfaces of the turbine. Since a ring-shaped seal portion is formed, a floating seal can be made between the turbine and the ring-shaped seal portion, and the fuel pumped in the fuel flow path from the suction port side to the discharge port side hits the relief part side. It can be surely prevented from leaking.

Further, the ring-shaped seal portion is parallel to the upper and lower surfaces of the turbine, and the width dimension in the radial direction is narrower than that of the contact relief portion. In addition to being able to perform a floating seal between them, a relatively large area can be formed on the lower and upper surfaces of the pump chamber of the pump housing on the inner side in the radial direction of the seal, eliminating frictional contact due to swelling of the turbine. be able to.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. In the embodiment, the same components as those of the prior art shown in FIG. 3 described above are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, 31 indicates a pump housing provided on the lower end side of the casing main body 2. The pump housing 31 is substantially the same as the pump housing 3 described in the prior art, and an outer housing 32 having a recess 32A and a shaft hole 32B. And an inner housing 33 having a through hole 33A. A pump chamber 7 having a fuel flow path 7A on the outer peripheral side is formed between the inner housing 33 and the outer housing 32, and a suction port 8 is formed in the outer housing 32. The discharge port 9 is formed in the.

Therefore, the bottom upper surface of the outer housing 32 and the lower surface of the inner housing 33 are located between the upper and lower surfaces of the turbine 11 and are inside the fuel passage 7A in the radial direction, and each of the turbine 11 is provided. Narrow ring-shaped seal portions 32C, 33B are formed radially inward of the blades 11B, 11C, and contact relief portions 32D, 33C for the upper and lower surfaces of the turbine 11 are provided radially inward of the seal portions 32C, 33B. It is designed to be recessed over the entire circumference. The clearance portions 32D and 33C are gaps between the upper and lower surfaces of the turbine 11 (see the maximum depth dimension c illustrated in FIG. 2).
However, it is formed in a concave curved shape so as to become gradually smaller from the inner peripheral portion located around the recess 32A and the through hole 33A toward the outer peripheral portion on the seal portion 32C, 33B side.

The seal portions 32C, 33B and the contact escape portions 32D, 33C are formed concentrically with the recess 32A and the through hole 33A, and the seal portions 32C, 33B are parallel to the upper and lower surfaces of the turbine 11, and between them. The minute gaps S, S are formed. The seal portions 32C and 33B form an oil film of fuel in the gaps S so that the fuel can be confined in the fuel passage 7A of the pump chamber 7, and a floating seal is provided between the upper and lower surfaces of the turbine 11. To do.

Further, as shown in FIG. 2, the seal portions 32C, 33B have a width dimension a in the radial direction which is sufficiently smaller and narrower than that of the contact escape portions 32D, 33C. On the upper and lower surfaces, the contact escape portions 32D, 33C can be formed in a relatively wide range on the radially inner side of the seal portions 32C, 33B,
It is possible to effectively prevent the occurrence of frictional contact due to swelling of the turbine 11.

Here, the outer diameter of the turbine 11 is 44 mm in the sealing portions 32C and 33B.
In this case, the width dimension a is about 1 mm, and the clearance dimension b between the upper and lower surfaces of the turbine 11 is about 5 to 30 μm, and particularly the minute clearance S is about 10 μm. Then, the hit escape part 32
The seals 32C and 33C are provided in order to provide a gap (b + c) larger than the minute gap S between the upper and lower surfaces of the turbine 11 and D and 33C.
The maximum depth dimension c with respect to B is formed to be about 10 to 20 μm, and when the turbine 11 is deformed due to swelling or the like, the turbine 11 has an upper bottom surface of the outer housing 32 or an inner housing.
It is designed to prevent frictional contact with the lower surface of 33. In addition, since the corresponding escape portions 32D, 33C have a maximum depth dimension c of about 10 to 20 μm with respect to the seal portions 32C, 33B, the oil film is formed between the upper and lower surfaces of the turbine 11 also in the corresponding escape portions 32D, 33C. To form a floating seal.

The fuel pump according to the present embodiment has the above-mentioned structure, and its basic operation is not different from that of the prior art.

Therefore, in this embodiment, the bottom ring upper surface of the outer housing 32 and the bottom surface of the inner housing 33 are provided with narrow ring-shaped seal portions 32C and 33B located radially inward of the fuel passage 7A, and the seal portions Since the contact relief portions 32D and 33C are provided in a concave curved shape on the radially inner side of the 32C and 33B, the turbine 1
Even when 1 swells with alcohol-blended gasoline or the like and is deformed, and the amount of deformation is large in the central portion of the turbine 11, the turbine 11 is prevented from coming into frictional contact with the outer housing 32 and the inner housing 33. It can be prevented by the portions 32D and 33C, and the fourth portion is provided on the upper and lower surface central portions of the turbine 11.
It is possible to prevent the abrasion mark 26 as illustrated in the drawing from occurring.

Further, the seal portions 32C, 33B can form a floating seal by forming an oil film between the upper and lower surfaces of the turbine 11, and the contact relief portions 32D, 33C have the maximum depth dimension with respect to the seal portions 32C, 33B. Since c is formed to about 10 to 20 μm,
A floating seal can be formed by forming an oil film in the corresponding escape portions 32D and 33C, and the fuel flow path
It is possible to reliably contain the fuel in the 7A and to pump this fuel from the suction port 8 side to the discharge port 9 side. That is, the fuel pressure-fed in the fuel passage 7A from the suction port 8 side to the discharge port 9 side is first given a relatively strong floating seal action by the seal portions 32C and 33B, and this seal action is the contact escape portion 32D. , 33C, so that the fuel can be reliably contained in the fuel passage 7A.

Therefore, according to the present embodiment, the fuel can be confined in the fuel passage 7A by the seal portions 32C, 33B, etc., and the fuel can be pumped from the suction port 8 side to the discharge port 9 side, and the turbine 11 is deformed. Even if it is done, the turbine 11 is prevented from coming into frictional contact with the outer housing 32 and the inner housing 33, and the relief portions 32D, 33
Since it can be prevented by C, it is possible to solve the problem such as the decrease in the discharge flow rate that occurs in the prior art.

In the above embodiment, the width dimension a of the seal portions 32C and 33B is set to 1
mm, the clearance b between the turbine 11 and the turbine is about 5 to 30 μm, and the maximum depth c of the contact relief portions 32D and 33C is 10 to 20 μm.
Although the value is set to about m, these values are not necessarily limited to the above values and may be appropriately changed. Further, the contact escape portions 32D, 33C do not necessarily have to be formed in a concave curved shape.

〔The invention's effect〕

As described in detail above, according to the present invention, the pump housing is positioned between the upper and lower surfaces of the turbine to form a ring-shaped seal portion and a contact escape portion, and the corresponding escape portion is The gap between the upper and lower surfaces of the turbine is gradually reduced from the inner peripheral portion toward the outer peripheral portion on the seal portion side, and the seal portion is parallel to the upper and lower surfaces of the turbine and has a diameter of Since the width dimension in the direction is narrower than that of the hit-and-release portion, a floating seal can be provided so that the fuel can be contained in the fuel passage by the seal portion, and the fuel can be fed from the suction port side. In addition to reliably pumping to the discharge side, even if the turbine is greatly deformed at the center (inner circumference) side due to swelling etc., the contact relief part effectively prevents the turbine from making frictional contact with the pump housing. Can, discharge flow rate can be solved problems such as lowered.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view of an essential part of a fuel pump, and FIG. 2 is a half sectional view showing an enlarged part of the essential part in FIG. 3 and 4 show the prior art, FIG. 3 is a longitudinal sectional view of a fuel pump, and FIG.
It is a perspective view of the turbine shown in a figure. 1 ... Casing, 2 ... Casing body, 7 ... Pump chamber, 7A ... Fuel passage, 10 ... Fixed shaft, 11 ... Turbine, 11B, 11C ... Blades, 13 ... Electric motor, 31 ... …
Pump housing, 32 ... Outer housing, 32C, 33B ...
… Seal part, 32D, 33C …… Escape part, 33 …… Inner housing.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Shown 60-143188 (JP, U) Shown 56-120392 (JP, U) Shown 59-14992 (JP, U) Shown 63- 174591 (JP, U) Actual public 46-28752 (JP, Y1) Actual public 32-3267 (JP, Y1)

Claims (1)

[Claims] 1. A pump housing provided on one side of a casing main body, a pump chamber provided in the pump housing, and having a fuel flow path formed on the outer peripheral side from a suction port toward a discharge port, and the pump chamber. A resin turbine, which is rotatably arranged in a chamber and has a parallel disk-shaped lower surface, and is provided with a large number of blades for pumping fuel in the fuel passage on the outer peripheral side, and the turbine. In a turbine type fuel pump comprising a motor provided in the casing body for rotationally driving, a pump chamber of the pump housing is provided on a lower surface with a groove bottom of each blade formed on an outer peripheral side of the turbine. Ring-shaped seal portion located radially inward of the turbine and providing a minute gap between the upper and lower surfaces of the turbine, and the minute gap between the upper and lower surfaces of the turbine located radially inward of the seal portion. It's a gap And a relief portion that gives a large gap, and the corresponding relief portion is formed such that the gap between the upper and lower surfaces of the turbine is gradually reduced from the inner peripheral portion toward the outer peripheral portion on the seal portion side. The turbine fuel pump is characterized in that the seal portion is parallel to the upper and lower surfaces of the turbine, and the width dimension in the radial direction is narrower than that of the contact relief portion.