JP5279320B2 - Fuel pump - Google Patents

Description

  The present invention relates to a fuel pump.

A typical fuel pump includes a cylindrical housing and a pump casing that is inserted into the housing and fixed. The pump casing accommodates the impeller inside. The housing is formed with a bent portion whose end is bent toward the inner peripheral side of the housing. The pump casing inserted in the housing is caulked and fixed to the housing by a bent portion. The fuel pump sucks and discharges fuel by rotating the impeller in the pump casing.
Patent Document 1 discloses a caulking structure in which a plug is fixed to an end surface of a cylindrical valve sleeve.

Japanese Utility Model Publication No. 4-75625

  When manufacturing a fuel pump, after inserting a pump casing in a housing, the edge part of a housing is bend | folded to an inner peripheral side (namely, a bending part is formed). As a result, the bent portion comes into contact with the pump casing, and the pump casing is caulked and fixed. At this time, since the bent portion springs back, the bent angle of the bent portion becomes slightly shallower than the actually bent angle. Therefore, in order to firmly fix the pump casing, it is necessary to press the bent portion against the pump casing with a high load. In this way, when the bent portion is pressed against the pump casing with a high load, a slight distortion occurs in the pump casing. Then, slight distortion also occurs on the inner surface of the pump casing (the inner surface of the space that houses the impeller). If slight distortion occurs on the inner surface of the pump casing, non-uniform force acts on the impeller during rotation of the impeller, making it difficult to rotate. As a result, the fuel discharge efficiency of the fuel pump is reduced.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fuel pump that can be manufactured without applying a high load to the pump casing.

The fuel pump of the present invention includes a housing and a pump casing. The housing is formed in a cylindrical shape. The pump casing houses the impeller inside and is inserted into the housing. At one end of the housing, a groove extending around the inner peripheral surface of the housing in the circumferential direction and the entire circumference of the housing are formed, and the groove is bent toward the inner peripheral side from the position of the groove. A bent portion is formed in contact with the pump casing at a position on one end side in the axial direction of the housing. The pump casing is caulked and fixed to the housing by the bent portion. When the pump casing and the housing are viewed in a cut plane passing through the axis of the housing, (1) the outer peripheral corner of one end of the pump casing is rounded, and (2) the end of the other end of the groove of the housing is It is located on the other end side from the outer peripheral corner of the pump casing. (3) The bent portion of the housing extends linearly from the end on one end side of the groove, and the linearly extending portion is the outer periphery of the pump casing. It is in contact with the corner.
In this fuel pump, a groove extending in the circumferential direction is formed in the housing. That is, the thickness of the housing is thin in the groove. Therefore, when the fuel pump is manufactured, when the housing is bent by the groove (that is, by forming the bent portion) and the pump casing is caulked and fixed, the bent portion is difficult to spring back. For this reason, even if the load which presses a bending part on a pump casing is not so high, a pump casing can be caulked and fixed by a bending part. Therefore, distortion is unlikely to occur in the pump casing during manufacturing. That is, this fuel pump is unlikely to be distorted in the pump casing and can discharge fuel with high efficiency.

Further, the fuel pump described above is formed such that the groove makes a round around the housing in the circumferential direction, and the bent portion is formed over the entire circumference of the housing . Since the groove is formed so as to make a round in the circumferential direction of the housing, a high load is not required when the housing is bent over the entire circumference of the housing to form the bent portion. A bent portion can be easily formed over the entire circumference of the housing. Further, since the pump casing is caulked and fixed to the bent portion over the entire circumference, no load is locally applied to the pump casing. Thus, distortion of the pump casing can be suppressed.

In the fuel pump described above, it is preferable that the groove is formed shallower toward the bent portion side.
According to such a configuration, when the housing is bent to form the bent portion, the bent position is stabilized.

In the fuel pump described above, it is preferable that the pump casing is caulked and fixed by a bent portion in a state where the pump casing is press-fitted into the housing.
According to such a configuration, the sealing performance between the pump casing and the housing is improved.

  The fuel pump of the present invention can be manufactured with almost no distortion in the pump casing. Therefore, a fuel pump with high fuel discharge efficiency can be provided.

The structure of the Example described in detail below is listed first.
(Feature 1) A step is formed on the inner peripheral surface of the housing. One end of the pump casing is in contact with the step, and the other end is fixed by being in contact with the bent portion.
(Feature 2) The groove is formed on the inner peripheral surface of the housing.

  A fuel pump according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic cross-sectional view of a fuel pump 100 of the present embodiment. The fuel pump 100 is installed in a fuel tank of an automobile or the like, and is used to supply fuel in the fuel tank to the engine. The fuel pump 100 includes a pump unit 70, a motor unit 10, and a discharge unit 80.

  As shown in FIG. 1, the motor unit 10 includes a housing 30, a permanent magnet 34, and a rotor 12. The housing 30 is a cylindrical case. The permanent magnet 34 is fixed to the inner peripheral surface of the housing 30. The rotor 12 is accommodated in the housing 30. The rotor 12 and the permanent magnet 34 are not in contact with each other, and a gap is formed between them.

The rotor 12 includes a shaft 14, a core 16, a case portion 18, and a commutator 20.
The shaft 14 is rotatably supported in the housing 30. Thereby, the entire rotor 12 can be rotated in the housing 30.
The core 16 is configured by laminating a plurality of metal plates. Although not shown, a coil is wound around the core 16.
The case portion 18 covers the periphery of the core 16.
The commutator 20 is fixed to the shaft 14 and the case portion 18. The commutator 20 has a plurality of electrode segments. Each electrode segment is connected to the end of the coil described above. Each electrode segment is in sliding contact with the brush 86 when the rotor 12 (that is, the commutator 20) rotates.

The discharge unit 80 includes a cover 82 and a brush 86.
The cover 82 is fixed to the upper part of the housing 30. A shaft support portion 84 is formed inside the cover 82. The shaft support part 84 supports the shaft 14 rotatably. A fuel discharge port 88 is formed in the upper part of the cover 82.
The brush 86 is installed inside the cover 82. The brush 86 can be supplied with electric power from the outside. When the brush 86 is in sliding contact with each electrode segment of the commutator 20, a current is supplied to the coil of the rotor 12.

The pump unit 70 includes an impeller 72 and a pump casing 74.
The pump casing 74 includes an upper casing 75 and a lower casing 76. Since the upper casing 75 and the lower casing 76 are in contact with each other, an impeller accommodating chamber 77 is formed inside the pump casing 74. In the upper casing 75, a shaft support portion 75c is formed. The shaft support portion 75c supports the shaft 14 so as to be rotatable. The pump casing 74 is fixed to the lower part of the housing 30. The fixing structure of the pump casing 74 will be described in detail later.
The impeller 72 is housed in the impeller housing chamber 77. The shaft 14 extends into the impeller accommodating chamber 77 and is engaged with the impeller 72. Thereby, the impeller 72 is rotatable together with the shaft 14. A plurality of recesses 72 a are continuously formed on the upper and lower surfaces of the impeller 72 along the circumferential direction of the impeller 72. The recess 72a formed on the upper surface and the recess 72a formed on the lower surface communicate with each other at the bottom. A concave groove 75a extending in a C shape is formed in a region facing the concave portion 72a of the upper casing 75. A concave groove 76a extending in a C shape is formed in a region facing the concave portion 72a of the lower casing 76. A step-up path 73 is formed by the concave grooves 75a and 76a and the respective concave portions 72a. The lower casing 76 is formed with a fuel intake port 76b that communicates the upstream end of the concave groove 76a (that is, the upstream end of the pressure increasing path 73) and the outside. The upper casing 75 is formed with a fuel discharge port 75b that communicates the downstream end of the concave groove 75a (that is, the downstream end of the pressure increasing path 73) and the outside.

  When a current is supplied to the brush 86 of the fuel pump 100, a current flows through the coil of the rotor 12 via the brush 86 and the commutator 20. As a result, the rotor 12 rotates and the shaft 14 of the rotor 12 also rotates. When the shaft 14 rotates, the impeller 72 rotates in the impeller accommodating chamber 77. When the impeller 72 rotates, fuel is sucked into the pressure increasing path 73 from the fuel suction port 76b. The fuel sucked into the booster passage 73 flows through the booster passage 73 while being boosted by the rotation of the impeller 72, and is sent out from the fuel discharge port 75b into the motor unit 10. The fuel fed into the motor unit 10 flows upward in the motor unit 10 and is discharged from the fuel discharge port 88 to the outside.

Next, a fixing structure that fixes the pump casing 74 to the housing 30 will be described. FIG. 2 is an enlarged view of the pump casing 74.
As shown in the drawing, a thin plate portion 36 is formed near the lower end surface of the housing 30 as compared with the upper portion (thick plate portion 35 in FIG. 2) of the housing 30. The outer peripheral surface 36 d of the thin plate portion 36 has the same diameter as the outer peripheral surface 35 d of the thick plate portion 35. On the other hand, the inner peripheral surface 36 a of the thin plate portion 36 has a larger diameter than the inner peripheral surface 35 a of the thick plate portion 35. Therefore, a step 37 is formed at the boundary between the thin plate portion 36 and the thick plate portion 35 on the inner peripheral surface of the housing 30.
The pump casing 74 is press-fitted into the inner peripheral surface 36 a of the thin plate portion 36. As shown in the figure, the pump casing 74 is press-fitted to a position where it abuts against the step 37. Thereby, the outer peripheral surface 74a of the pump casing 74 and the inner peripheral surface of the housing 30 (that is, the inner peripheral surface 36a of the thin plate portion 36) are sealed by pressure contact. Further, the pump casing 74 is prohibited from rotating relative to the housing 30 due to the pressure contact between the pump casing 74 and the housing 30.

  FIG. 3 shows an enlarged view near the lower end of the thin plate portion 36. As shown in FIG. 3, a groove 36 c extending in the circumferential direction of the housing 30 is formed in the vicinity of the lower end of the inner peripheral surface 36 a of the thin plate portion 36. The groove 36 c makes a round on the inner peripheral surface 36 a in the circumferential direction of the housing 30. The groove 36c is formed shallower toward the lower end side. The lower end part 36b of the thin plate part 36 is bent inward from the groove 36c (hereinafter, the lower end part 36b may be referred to as a bent part 36b). As a result, the bent portion 36 b is in contact with the pump casing 74. The bent portion 36b is formed over the entire circumferential direction of the housing 30 (that is, the lower end portion 36b of the thin plate portion 36 is bent to the inner peripheral side by the groove 36c over the entire circumference). As a result, the pump casing 74 is fixed by caulking. That is, the pump casing 74 is fixed between the step 37 and the bent portion 36b.

  When manufacturing the fuel pump 100, as shown in FIG. 4, the pump casing 74 is press-fitted into the housing 30 in a state where the lower end portion 36b is not bent. And the lower end part 36b is bent inside the housing 30 from the groove | channel 36c, and the bending part 36b is formed. The lower end portion 36 b is bent over the entire circumference of the housing 30. Further, the lower end portion 36b is bent until it comes into close contact with the pump casing 74 as shown in FIG.

When the lower end portion 36b is bent, the lower end portion 36b attempts to return to a shallower angle than the angle bent by the springback. For this reason, it is necessary to press the lower end part 36 b toward the pump casing 74. However, since the lower end portion 36b is bent in the groove 36c (that is, the thickness of the housing 30 in the groove 36c is thin), the spring back hardly occurs. Therefore, the lower end 36 b can be brought into close contact with the pump casing 74 without pressing the lower end 36 b against the pump casing 74 so strongly. For this reason, since a high load is not applied to the pump casing 74 at the time of bending, distortion of the pump casing 74 due to the load is suppressed.
In addition, since a very high load is not required to bend the lower end portion 36b as described above, it becomes easy to appropriately bend the entire circumference of the lower end portion 36b. Since the entire circumference of the lower end portion 36 b can be favorably bent, the pump casing 74 can be firmly fixed to the housing 30. Further, since the entire circumference of the lower end portion 36b is bent, a locally high load is not applied to the pump casing 74 (when the lower end portion 36b is partially bent, the pump casing 74 is in contact with the bent portion. High load is applied locally). Also by this, the distortion of the pump casing 74 is suppressed.
Thus, the fuel pump 100 of the present embodiment can be assembled without applying a very high load to the pump casing 74. Therefore, distortion of the pump casing 74 hardly occurs during assembly. That is, since the inner surface of the impeller accommodating chamber 77 is suppressed from being distorted, a nonuniform force does not act on the impeller 72 when the fuel pump 100 is used. The impeller 72 can rotate smoothly. Therefore, the fuel pump 100 has high fuel discharge efficiency. Moreover, since distortion of the outer peripheral surface 74a of the pump casing 74 is also suppressed, high sealing performance is ensured at a contact portion between the outer peripheral surface 74a and the inner peripheral surface of the housing 30 (that is, the inner peripheral surface 36a of the thin plate portion 36). be able to. This also improves the discharge efficiency of the fuel pump 100.
Further, as shown in FIGS. 3 and 4, the groove 36c is formed shallower toward the lower end side (that is, toward the bent portion 36b side). Therefore, when the lower end portion 36b is bent, the bent position is stabilized (that is, the thin plate portion 36 is bent at the deepest position of the groove 36c). Therefore, the fuel pump 100 can be manufactured with stable quality.

  In the above-described embodiment, the groove 36c is formed on the inner peripheral surface 36a of the thin plate portion 36, but may be formed on the outer peripheral surface 36d. That is, a groove 36 c that makes a round on the outer peripheral surface 36 d in the circumferential direction of the housing 30 is formed. Even if the groove 36c is formed in this way, the thin plate portion 36 becomes thin at the portion where the groove 36c is formed, so that the lower end portion 36b can be easily bent. Thus, also when forming the groove | channel 36c in 36 d of outer peripheral surfaces, it is preferable to form so that the groove | channel 36c may become shallow, so that it goes to a lower end side. Thereby, the bending position when the lower end portion 36b is bent can be stabilized. Further, the groove 36c may be formed on both the inner peripheral surface 36a and the outer peripheral surface 36d of the thin plate portion 36.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

1 is a schematic side view of a fuel pump 100. FIG. The expanded sectional view of the pump casing 74. FIG. The expanded sectional view of the thin-plate part 36. FIG. The expanded sectional view of the thin-plate part 36 before formation of the bending part 36b.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10: Motor part 12: Rotor 14: Shaft 30: Housing 34: Permanent magnet 36: Thin plate part 36a: Inner peripheral surface 36b: Bending part 36c: Groove 36d: Outer peripheral surface 37: Step 70: Pump part 72: Impeller 73: Booster Path 74: Pump casing 75: Upper casing 76: Lower casing 77: Impeller accommodating chamber 80: Discharge part 82: Cover 88: Fuel discharge port 100: Fuel pump

Claims (3)

A tubular housing;
A pump casing containing an impeller inside and inserted into the housing;
With
At one end of the housing
A groove extending around the inner peripheral surface of the housing in the circumferential direction;
It is formed over the entire circumference of the housing, bent from the groove to the inner peripheral side, and a bent portion is formed that contacts the pump casing at a position on one end side in the axial direction of the housing from the position of the groove.
The pump casing is caulked and fixed to the housing by the bent portion ,
When the pump casing and the housing are viewed in a cut plane passing through the axis of the housing,
(1) The outer peripheral corner of one end of the pump casing has a roundness,
(2) The end on the other end side of the groove of the housing is located on the other end side from the outer peripheral corner of the pump casing,
(3) The bent portion of the housing extends linearly from the end on one end side of the groove, and the linearly extending portion is in contact with the outer peripheral corner of the pump casing.
A fuel pump characterized by that. The groove is formed shallower toward the bent portion side ,
When the pump casing and the housing are viewed in a cut plane passing through the axis of the housing,
At the end on one end side of the groove of the housing, the angle between the groove and the inner peripheral surface of the housing is an obtuse angle,
2. The fuel pump according to claim 1, wherein a corner formed at the obtuse angle is in contact with an outer peripheral corner of the pump casing .   The fuel pump according to claim 1 or 2, wherein the pump casing is caulked and fixed by a bent portion in a state of being press-fitted into the housing.

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