Patent Application
20200355149
The present disclosure relates to a fuel supply device.
In a fuel supply device including a fuel pump disposed in a fuel tank, a supporting pillar connects a flange that is a lid of the fuel tank to a pump unit that includes the fuel pump. In the fuel supply device, the supporting pillar is press-fit into an inner tube of the flange.
A fuel supply device of the present disclosure includes a flange, a pump unit, a supporting pillar, and a boss. The flange is attached to an opening portion of a fuel tank. The pump unit is disposed in the fuel tank and discharges a fuel out of the fuel tank. The supporting pillar connects the flange to the pump unit. The boss is fixed to the flange and the supporting pillar has one end inserted into the boss.
A direction perpendicular to an axial direction of the supporting pillar is defined as an axis perpendicular direction. The boss is made of a material different from that of the flange or the boss is formed as a different member from the flange. The boss includes a stress concentration portion to be preferentially broken when a force, in the axis perpendicular direction, having a predetermined value or more is applied to the other end of the supporting pillar.
The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description made with reference to the accompanying drawings.
To begin with, examples of relevant techniques will be described.
In a fuel supply device including a fuel pump disposed in a fuel tank, a supporting pillar connects a flange that is a lid of the fuel tank to a pump unit that includes the fuel pump. In the fuel supply device, the supporting pillar is press-fit into an inner tube of the flange.
When a large impact is applied to the fuel tank due to a vehicle collision or the like, a large inertia force is applied to the pump unit. In addition to the inertia force, if a load generated when the fuel around the pump unit is shaken is applied to the flange through the supporting pillar, the flange may be broken. In this case, if a crack passing through the tank is generated in the flange, the fuel may leak from the fuel tank through the crack. The inner tube of the flange is integrally molded with a flange body with a resin. Thus, a crack generated at a root of the inner tube may pass through the fuel tank.
It is objective of the present disclosure to provide a fuel supply device that can restrict a fuel from leaking from a fuel tank.
A fuel supply device of the present disclosure includes a flange, a pump unit, a supporting pillar, and a boss. The flange is attached to an opening portion of a fuel tank. The pump unit is disposed in the fuel tank and discharges a fuel out of the fuel tank. The supporting pillar connects the flange to the pump unit. The boss is fixed to the flange and the supporting pillar has one end inserted into the boss.
A direction perpendicular to an axial direction of the supporting pillar is defined as an axis perpendicular direction. In a first aspect of the present disclosure, the boss is made of a material different from that of the flange. In a second aspect of the present disclosure, the boss is formed as a different member from the flange. The boss includes a stress concentration portion to be preferentially broken when a force, in the axis perpendicular direction, having a predetermined value or more is applied to the other end of the supporting pillar.
The boss has the stress concentration portion, and thus breakage of the boss occurs prior to the breakage of the flange when an excess amount of a load is applied to the fuel tank. The flange and the boss are made of different materials or formed as different members, thus a crack generated at the stress concentration portion stops expanding at a boundary between the boss and the flange. Therefore, a crack passing through the flange is restricted from generating and the fuel leakage from the fuel tank can be restricted.
Hereinafter, embodiments will be described according to the drawings. In the embodiments, substantially the same components are donated by the same reference numerals and description thereof is omitted. The drawings are schematically drawn for easy understanding of the configuration. The dimensions, angles, and dimensional ratios in the drawings are not necessarily limiting.
A fuel supply device 10 in a first embodiment is illustrated in
At first, a basic configuration of the fuel supply device 10 will be described. As shown in
The sub tank 12 is disposed in the fuel tank 5 and includes a case 21 and a lid 22. The case 21 is disposed on a bottom 23 of the fuel tank 5 and a fuel in the fuel tank 5 flows into the sub tank 12. The fuel pump 13 is housed in the sub tank 12 and discharges the fuel outward the fuel tank 5.
The flange 14 is shaped into a disc shape with a resin. The flange 14 is attached to an opening portion 25 of a ceiling 24 of the fuel tank 5 to liquid-tightly seal the opening portion 25. The flange 14 includes a fuel supply pipe 26 and an electrical connector 27. The fuel supply pipe 26 is connected to a discharging outlet 29 of the fuel pump 13 through a flexible tube 28, thus a fuel discharged out of the fuel pump 13 is guided to the outside of the fuel tank 5 through the fuel supply pipe 26. The electrical connector 27 includes a terminal therein to electrically connect the fuel pump 13 and a residual quantity detector (not shown) to an external member.
Each of the supporting pillars 15 is made, for example, of metal and connects the flange 14 to the pump unit 11. The supporting pillar 15 has an end portion 31 facing the pump unit 11 and being inserted into a through hole 32 of the sub tank 12. The supporting pillar 15 supports the sub tank 12 such that the sub tank 12 can be positioned close to and away from the flange 14. The springs 16 are respectively disposed outside of the supporting pillars 15 and bias the sub tank 12 against the bottom 23 of the fuel tank 5. Thus, a position of the sub tank 12 against the bottom 23 of the fuel tank 5 is stabilized regardless of a tolerance in manufacture and a deformation.
Next, fixing structures of the supporting pillars 15 will be described with reference to
The flange 14 is a tank lid of the fuel tank 5. The tank lid needs a chemical resistance (in particular, an acid resistance) because the tank lid is exposed to an outside of the fuel tank 5. In contrast, a portion to which the supporting pillar 15 is fixed needs an impact resistance. The tank lid and the portion to which the supporting pillar 15 is fixed are often integrally molded with the same material. Thus, the material demands both of chemical resistance and impact resistance. However, an appropriate material having both resistances is not present actually, thus one of the resistances is often impaired.
In this embodiment, the fuel supply device 10 additionally includes the bosses 33 formed as a different member from the flange 14 as a portion to which the supporting pillars 15 are fixed. The flange 14 as a tank lid is made of a material having a high rigidity and being superior in chemical resistance and fuel resistance. Each of the bosses 33 is made of a material having a high toughness and being superior in fuel resistance. The material of the flange 14 may be polyphenylene sulfide-glass fiber (i.e., PPS-GF), polyphthalamide-glass fiber (i.e., PPA-GF), polyphenylene sulfide (i.e., PPS), polyphenylene sulfide in impact resistance (i.e., PPS-I that is elastomer modified), or polyphthalamide (i.e., PPA). The material of the boss 33 may be PPS, PPS-I, PPA, or POM. Thus, the flange 14 is restricted from cracking when the flange 14 is exposed to an acid liquid and the boss 33 can be improved in a durability against an external impact.
In this embodiment, a crack passing through the fuel tank 5 is restricted from generating in the flange 14 when a load caused by a vehicle collision is applied to the bosses 33 and the flange 14 through the supporting pillars 15. Structures of each of the bosses 33 and the like including a configuration to restrict the crack will be described in detail.
The bosses 33 are disposed between the flange 14 and the pump unit 11. Each of the bosses 33 includes a flange fixing member 34 and a supporting pillar fixing member 35.
The flange fixing member 34 is fixed to a supporter 36 of the flange 14. In the first embodiment, the flange fixing member 34 is integrally molded with the flange 14 by an insert molding when the flange 14 is molded. The flange fixing member 34 is embedded into the supporter 36. The supporter 36 is located between a body of the flange 14 and the pump unit 11 and has a tube shape to surround an outer periphery of the flange fixing member 34. The supporter 36 has a root having a round shape, i.e., the root of the supporter 36 has a curved surface in a vertical cross section.
The flange fixing member 34 has a large diameter portion 37 and a small diameter portion 38 located between the large diameter portion 37 and the pump unit 11. The flange fixing member 34 has an outer peripheral surface having a smaller diameter at a portion closer to the pump unit 11. The supporter 36 includes an inner annular protrusion 39 that protrudes toward the outer peripheral surface of the small diameter portion 38. The flange fixing member 34 has a corner 47 between the large diameter portion 37 and the small diameter portion 38 and the corner has a round shape. The corner 47 is an engaging portion that faces the pump unit 11 in an axial direction of the supporting pillar 15 and is engaged with the inner annular protrusion 39. Since the corner 47 is engaged with the inner annular protrusion 39, the boss 33 is prevented from slipping out. Hereinafter, the axial direction of the supporting pillar 15 is refereed as an axial direction.
The flange fixing member 34 includes a recess 48 recessed from a surface of the boss 33 facing the flange 14 in the axial direction. The recess 48 enables to reduce a difference of the thickness of the boss 33 as much as possible and improve a moldability of the boss 33. The flange 14 includes a protrusion 49 protruding into the recess 48.
The supporting pillar fixing member 35 protrudes from the flange fixing member 34 toward the pump unit 11. The supporting pillar fixing member 35 defines an insertion hole 42 that opens at an end surface 41 of the boss 33 facing the pump unit 11. The supporting pillar 15 has an end portion 43 facing the flange 14 and being inserted into the insertion hole 42. In the first embodiment, the insertion hole 42 has a tapered inner surface and the end portion 43 of the supporting pillar 15 has a fir tree shape. The fir tree shape is a shape in which multiple tapered surfaces are stacking in the axial direction. The end portion 43 of the supporting pillar 15 is press-inserted into the insertion hole 42 to fix the supporting pillar 15 to the boss 33. There is a cavity 44 defined between a bottom surface of the insertion hole 42 and an end surface of the end portion 43.
An outer diameter of a portion of the supporting pillar fixing member 35 closer to the flange fixing member 34 is larger than the small diameter portion 38. There is a step 45 between the supporting pillar fixing member 35 and the flange fixing member 34. The step 45 is a contact portion facing away from the pump unit 11 and being in contact with a flange end surface 46 of the supporter 36 in the axial direction.
The boss 33 and an outer surface of the supporting pillar 15 are in contact with each other at a contact portion having a first position P1 closest to the pump unit 11. The boss 33 and the flange 14 are in contact with each other at a contact portion having a second position P2 closest to the pump unit 11. The boss 33 and the outer surface of the supporting pillar 15 are in contact with each other at a contact portion having a third position P3 closest to the flange 14. The first position P1 and the third position P3 are located between the second position P2 and the pump unit 11 in the axial direction. The cavity 44 is defined between the third position P3 and the second position P2 in the axial direction.
The boss 33 is made of a different kind of resin from the flange 14. The materials of the boss 33 and the flange 14 are selected between materials satisfying the following conditions (A) to (E). The conditions (B) to (E) are described in
(A) The material of the boss 33 has a melting temperature equal to or greater than a melting temperature of the material of the flange 14.
(B) The material of the boss 33 has a breaking strength σ2 less than a breaking strength σ1 of the material of the flange 14.
(C) The material of the boss 33 has an elastic modulus E2 less than an elastic modulus E1 of the material of the flange 14.
(D) The material of the boss 33 has a breaking elongation ε2 greater than a breaking elongation ε1 of the material of the flange 14.
(E) The breaking elongation ε2 of the material of the boss 33 is greater than a predetermined breaking elongation ε3. The predetermined breaking elongation ε3 is a value required to restrict a crack of the supporting pillar 15 generated when press-fit and a decrease in a force required to draw the supporting pillar 15.
When a large impact force is applied to the fuel tank 5 due to a vehicle collision, both of an inertia force acting on the pump unit 11 and a load generated when the fuel around and inside the pump unit 11 is shaken are applied to the end portion 31 of the supporting pillar 15 in a direction perpendicular to the axis of the supporting pillar 15 (hereinafter, referred as an axis perpendicular direction). Since these forces have the supporting pillar 15 tilt relative to the end portion 43 as a fulcrum point, the boss 33 and the flange 14 that are supporting structures of the end portion 43 receive the forces. The boss 33 includes a stress concentration portion 40 that is preferentially broken when a force having a predetermined value or more in the axis perpendicular direction is applied to the end portion 31 of the supporting pillar 15.
In the first embodiment, when a force in the axis perpendicular direction is applied to the end portion 31, the corner 47 that is located at a side of the stress concentration portion 40 opposite to the pump unit 11 is engaged with the inner annular protrusion 39, so that the large diameter portion 37 resists against a tilt of the supporting pillar 15. Additionally, the step 45 is in contact with the flange end surface 46 of the supporter 36 and restricts the flange fixing member 34 (i.e., a portion of the boss 33 located between the step 45 and the flange 14) and the supporter 36 from being tilted. The third position P3 is closer to the pump unit 11 than the second position P2 and the stress concentration portion 40 in the axial direction. The cavity 44 is defined between the third position P3 and the second position P2 in the axial direction. Thus, the boss 33 receives a force to have the boss 33 bend around a portion of a corner of the step 45 as a fulcrum point in a direction in which the inertia force is applied (hereinafter, refereed as an inertia force direction). Therefore, a stress is concentrated on a portion of the corner of the step 45 that is located opposite to the fulcrum point of bending in the inertia force direction, has a smallest outer diameter (hereinafter referred as a smallest diameter portion), and is outside of a press-fit area of the boss 33 in which the supporting pillar 15 is press-fit into the boss 33. That is, the portion of the corner of the step 45 serves as the stress concentration portion 40. A portion outside the press-fit area is a range that is not overlapped with a portion of the boss 33 into which the supporting pillar 15 is press-fit in the axial direction. Because of this and the conditions (B) and (C) for selecting the materials, the stress concentration portion 40 of the boss 33 is broken prior to the flange 14 when a force having a predetermined value or more is applied to the end portion 31 in the axis perpendicular direction.
As described above, in the first embodiment, the fuel supply device 10 includes the sub tank 12, the fuel pump 13, the flange 14, the supporting pillars 15, and the bosses 33. The flange 14 is attached to the opening portion 25 of the fuel tank 5. The supporting pillars 15 support the sub tank 12 such that the sub tank 12 can be positioned close to and away from the flange 14. The bosses 33 are fixed to the flange 14 and the end portions 43 of the supporting pillars 15 are respectively inserted into the bosses 33. Each of the bosses 33 is made of a material different from that of the flange 14 and has the stress concentration portion 40 that is selectively broken when a force having a predetermined value or more in the axis perpendicular direction is applied to the end portion 31 of the supporting pillar 15.
Each of the bosses 33 includes the stress concentration portion 40, and therefore breakage of the bosses 33 occurs prior to the breakage of the flange 14 when an excess amount of load is applied to the fuel supply device 10. The flange 14 and the boss 33 are made of different materials, thus a crack generated at the stress concentration portion 40 stops expanding at a boundary between the boss 33 and the flange 14. As a result, the crack passing through the flange 14 is restricted from generating, which restricts the fuel from leaking from the fuel tank 5.
In the first embodiment, since the material of the boss 33 has a melting temperature equal to or higher than a melting temperature of the material of the flange 14, the boss 33 is restricted from melting and deforming when the boss 33 is inserted into the flange and molded. Thus, the crack at the stress concentration portion 40 can be stopped expanding at the boundary between the boss 33 and the flange 14.
In the first embodiment, the material of the boss 33 has the breaking strength σ2 less than the breaking strength σ1 of the material of the flange 14. Thus, the boss 33 is preferentially broken when an impact energy is applied.
In the first embodiment, the material of the boss 33 has the elastic modulus E2 less than the elastic modulus E1 of the material of the flange 14. Thus, the boss 33 is preferentially deformed so that the flange 14 can be prevented from receiving an excess amount of force.
In the first embodiment, the material of the boss 33 has the breaking elongation ε2 greater than the breaking elongation ε1 of the material of the flange 14. Thus, the supporting pillar 15 is restricted from cracking when press-fit into the boss 33 and a force required to draw the supporting pillar 15 can be prevented from decreasing. In addition, an impact resistance is secured and a design flexibility is improved.
In the first embodiment, the first position P1 is located between the second position P2 and the pump unit 11. The third position P3 is located between the second position P2 and the pump unit 11. Thus, when the force in the axis perpendicular direction is applied to the end portion 31 of the supporting pillar 15, the boss 33 receives the force to have the boss 33 bend at the second position P2 relative to the first position P1 and the third position P3. Thus, the boss 33 can be broken when the excess amount of the load is applied.
In the first embodiment, the stress concentration portion 40 is the smallest outer diameter portion of the boss 33 that is outside of the press-fit area. The corner of the step 45 serves as the stress concentration portion 40. When the force in the axis perpendicular direction is applied to the end portion 31 of the supporting pillar 15, the boss 33 receives a force to have the boss 33 bend around the portion of the corner of the step 45 in the inertia force applying direction. As a result, a stress can be concentrated on the stress concentration portion 40 (i.e., the corner of the step 45) that is located opposite to the fulcrum point of bending in the inertia force applying direction.
In the first embodiment, the boss 33 includes the corner 47 that faces the pump unit 11 and is engaged with the flange 14. The corner 47 is located at a side of the stress concentration portion 40 opposite to the pump unit 11. When a force in the axis perpendicular direction is applied to the end portion 31, the large diameter portion 37 resists against a tilt of the supporting pillar 15 by the corner 47 engaging with the inner annular protrusion 39. Thus, the boss 33 is likely to bend at a position between the large diameter portion 37 and the press-fit area of the boss 33, and the boss 33 can be preferentially broken when the excess amount of the load is applied.
In the first embodiment, the boss 33 includes the flange fixing member 34 embedded in the supporter 36 of the flange 14 and the supporting pillar fixing member 35 protruding from the supporter 36 toward the pump unit 11. The supporting pillar fixing member 35 includes the step 45 that faces away from the pump unit 11 and is in contact with the flange end surface 46 of the supporter 36. Thus, when the force in the axis perpendicular direction is applied to the end portion 31, the step 45 is pressed against the flange end surface 46 of the supporter 36, which restricts the flange fixing member 34 and the supporter 36 from being tilted. In contrast, the boss 33 is bent at a position, as a fulcrum point, around the corner of the step 45 in the inertia force applying direction. Thus, a stress is concentrated on the corner of the step 45 located opposite to the fulcrum point of bending in the inertia force applying direction. Since the boss 33 is not tilted but is bent, a stress at the supporter 36 of the flange 14 is reduced and a thickness of the supporter 36 can be made relatively thinner.
In a second embodiment, as shown in
In a third embodiment, as shown in
In a fourth embodiment, as shown in
In a fifth embodiment, as shown in
In a sixth embodiment, as shown in
In other embodiment, as shown in
In other embodiment, as shown in
In another example of the first embodiment, as shown in
In other embodiment, as shown in
In other embodiment, as shown in
In other embodiment, as shown in
In other embodiment, as shown in
The L shaped pipe 162 has a tube portion 165 to be inserted between the fuel supply pipe 161 and the clip supporter 163 and a connector 166 protruding from an end of the tube portion 165. The tube portion 165 includes a collar 167 at a middle part of the tube portion 165. A spacer 171 and an ο ring 172 are disposed in the tube portion 165 at an insertion end 168 in this order from an opening of the tube portion 165 through which the fuel supply pipe 161 is inserted.
As shown in
Hereinafter, an embodiment shown in
In contrast, in this embodiment, a gap G1 between the fuel supply pipe 161 and the L shaped pipe 162 is larger than a gap g1 in the comparative example, a protruding height H1 of the fuel supply pipe 161 that protrudes from the flange 189 is less than a protruding height h1 of the fuel supply pipe 161 in the comparative example, and a gap G2 between the insertion end 168 and the L shaped pipe 162 is smaller than a gap g2 in the comparative example. Thus, when a load F is applied to the L shaped pipe 162 to have the L shaped pipe 162 tilt as shown in
The clip 164 in the present embodiment has a thickness larger than that in the comparative example, thus a strength of the clip 164 is improved. Since the spacer 171 has a portion reduced in thickness, in the axis perpendicular direction, toward the insertion end 168, the spacer 171 is prevented from being in contact with a tip end of the fuel supply pipe 161 when the L shaped pipe 162 is tilted.
In another example of the fifth embodiment, the flange fixing member of the boss may be welded to the insertion hole of the supporter of the flange, or the stress concentration portion may be formed as a cutout portion. In another example of the sixth embodiment, the stress concentration portion may be formed as a corner of a step or a bottom of a cutout portion.
In other embodiment, the boss may be formed as a different member from the flange while the boss is made of the same kind of material with the flange. In this case, a crack generated at the stress concentration portion is stopped expanding at the boundary between the boss and the flange, thus the crack passing through the flange is restricted from generating and the fuel is prevented from leaking out of the fuel tank. The material of the boss and the flange may be POM, PPS, PPS-I, PPA, PPS-GF, or PPA-GF.
In other embodiment, the recess included by one of the flange fixing member of the boss and the flange and the protrusion included by the other are not necessary disposed.
In other embodiment, the shape of the end portion of the supporting pillar is not limited to the fir tree shape or tapered shape.
In other embodiment, the pump unit may not include the sub tank while the pump unit includes the fuel pump. In other embodiment, the fuel supply device may not include the spring and may be configured as another structure such as a hanging type in which the pump unit is hanging from the flange.
The present disclosure is described based on embodiments. However, the present disclosure is not limited to the embodiments and configurations described in embodiments. The present disclosure includes various alternations and modifications in a range of equivalent. Various combinations and embodiments and various combinations and embodiments to which one element or elements are added are included in the range and technical features of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-016355 | Feb 2018 | JP | national |
| 2019-011338 | Jan 2019 | JP | national |
The present application is a continuation application of International Patent Application No. PCT/JP2019/003093 filed on Jan. 30, 2019, which designated the U.S. and claims the benefit of priority from Japanese Patent Application No. 2018-016355 filed on Feb. 1, 2018, and Japanese Patent Application No. 2019-011338 filed on Jan. 25, 2019. The entire disclosure of all of the above applications are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2019/003093 | Jan 2019 | US |
| Child | 16941903 | US |
