JPH10176626A - Bellows type fuel pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To support a torque by a shaft when a bellows is contracted/expanded by a driving mechanism so as to ensure durability of the bellows by offsetting a center of the bellows, and a center of a shaft which is inserted in a buried member stored in the bellows and which is fixed to the bellows. SOLUTION: When a bellows 20 is expanded by rotation of an axial cam 13, an intake passage 21 is opened by an inlet side check valve 41, and fuel is intake in a clearance of a pump chamber 40 from a communicating passage 51. When the bellows 20 is contracted, pressure in a pump chamber 40 is raised, an output side check valve 42 is opened, and compressed fuel is supplied from a delivery passage 22 to a fuel injection valve of each cylinder. In this time, since a shaft 60 which is press-fitted to a crown surface member 34 is integratedly formed in a condition offset from a center shaft of the bellows 20, a torque toward the crown surface member 34 is supported by a buried member 50 into which the shaft 60 being fitted. It is thus possible to prevent torsion of the bellows 20, and it is also possible to ensure is durability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a technique for miniaturizing a bellows type fuel pump.

[0002]

2. Description of the Related Art Conventional bellows type fuel pumps include:
For example, a fuel pump disclosed in Japanese Patent Application Laid-Open No. 4-187,865 is known. This fuel pump includes a tubular bellows 70 which can be extended and contracted as shown in FIG.
The pump function is exhibited by the zero expansion / contraction drive.

[0003]

However, in such a conventional bellows type fuel pump, the cam 71
And the roller 72 which is set in contact with the roller and is set for the purpose of preventing seizure and reducing the frictional force is set on the upper part of the bellows 70, so that the axial length of the bellows 70 is increased, so that a vehicle that can be mounted is provided. There was a problem that it was limited and lacked versatility. Further, there is a problem that the cost is high from the viewpoint of the processing accuracy of the roller 72 and the increase in the number of parts.

The present invention has been made in view of such conventional problems, and a bellows type fuel pump capable of realizing size reduction and cost reduction while satisfying the durability and prevention of seizure of the bellows portion. The purpose is to provide.

[0005]

According to one aspect of the present invention, there is provided a bellows type fuel pump according to claim 1, wherein the bellows-type fuel pump has an expandable / contractible tubular bellows, a housing for fixing a fixed end of the bellows, and a bellows type. A drive mechanism for reciprocating the movable end in the expansion and contraction direction, a suction passage for guiding fuel to the bellows, an inlet check valve for opening fuel flowing from the suction passage to the bellows, and a fuel from the bellows In a bellows-type fuel pump including a discharge passage for discharging the fuel and an outlet-side check valve that opens for fuel flowing from the bellows to the discharge passage, a columnar embedded member is housed in the bellows, While fixing one end of the embedded member to the housing side, the other end of the embedded member faces the movable end of the bellows, and the bellows is attached to the other end of the embedded member. While drilled guide holes offset from the center, characterized in that the insertion of the shaft fixed to the bellows side to the guide hole.

In the bellows type fuel pump according to the present invention, since the center of the bellows and the center of the shaft inserted into the buried member and fixed to the bellows are offset, the bellows is driven by, for example, a swash plate as a driving mechanism. The shaft can support a torsional force on the bellows when the shaft expands and contracts. Therefore, even if the driving mechanism and the movable end of the bellows do not generate a large sliding motion, the durability of the bellows can be sufficiently ensured. As a result, the conventional image sticking prevention roller can be eliminated, so that downsizing and cost reduction can be realized.

According to another aspect of the present invention, there is provided a bellows-type fuel pump according to claim 2, wherein the bellows-type fuel pump is expandable and contractible, a housing for fixing a fixed end of the bellows, and a movable end of the bellows for expansion and contraction. Drive mechanism for reciprocating in a direction, a suction passage for guiding fuel to the bellows, an inlet check valve for opening fuel flowing from the suction passage to the bellows, and a discharge for discharging fuel from the bellows. In a bellows-type fuel pump including a passage and an outlet-side check valve that opens for fuel flowing from the bellows to the discharge passage, a columnar embedded member is housed in the bellows, and One end is fixed to the housing side, the other end of the embedded member faces the movable end of the bellows, and a guide hole is formed in the other end of the embedded member. A shaft fixed to the bellows side is inserted into the guide hole, and a key and a key groove for stopping the shaft from rotating with respect to the embedded member are formed between the guide hole and the shaft. .

In the bellows type fuel pump according to the second aspect, the buried member and the shaft inserted into the buried member and fixed to the bellows are prevented from rotating by the key and the key groove. When the bellows expands and contracts by the swash plate, the torsional force on the bellows can be supported by the key and the key groove. Therefore, even if the driving mechanism and the movable end of the bellows do not generate a large sliding motion, the durability of the bellows can be sufficiently ensured. As a result, the conventional image sticking prevention roller can be eliminated, so that downsizing and cost reduction can be realized.

The bellows type fuel pump according to claim 3 is
A through hole is formed in the buried member so as to communicate an outer peripheral portion of the buried member with the guide hole. In the bellows type fuel pump according to the third aspect, since the through hole communicating the outer peripheral portion of the buried member and the guide hole is formed, even if the shaft moves up and down due to the expansion and contraction of the bellows, the shaft is connected to the shaft. Fuel between the guide hole is discharged or flows into the outer peripheral portion of the embedded member from the through hole. Therefore, the expansion and contraction movement of the bellows is not hindered by the fuel pressure loss in the guide hole, and the increase in the driving torque can be suppressed.

The bellows type fuel pump according to claim 4 is
The embedded member is formed with a through hole communicating the outer peripheral portion of the embedded member and the guide hole, and a groove is formed in the outer peripheral portion of the embedded member along a direction in which the bellows expands and contracts. . In the bellows type fuel pump according to the fourth aspect, the through hole communicating the outer peripheral portion of the buried member and the guide hole is formed, and the groove in the bellows extending and contracting direction is formed on the outer peripheral portion of the buried member. Even if the shaft moves up and down with the expansion and contraction of the fuel, the fuel between the shaft and the guide hole is discharged or flows into the outer peripheral portion of the embedded member from the through hole. Therefore, the expansion and contraction movement of the bellows is not hindered by the fuel pressure loss in the guide hole, and the increase in the driving torque can be suppressed.

In addition, since the groove in the bellows expansion and contraction direction is formed on the outer peripheral portion of the buried member, a sufficient fuel can be supplied into the bellows while using a wasted space in the bellows, and the size of the bellows can be reduced. And cost reduction can be realized.

According to a fifth aspect of the present invention, there is provided a bellows type fuel pump.
A groove is formed in an outer peripheral portion of the shaft along a direction in which the bellows expands and contracts. In the bellows type fuel pump according to the fifth aspect, since the groove in the bellows expansion and contraction direction is formed on the outer peripheral portion of the shaft, even if the shaft moves up and down with the expansion and contraction of the bellows, the shaft and the guide hole are not connected. The fuel in between drains or flows in from the groove. Therefore, the expansion and contraction movement of the bellows is not hindered by the fuel pressure loss in the guide hole, and the increase in the driving torque can be suppressed.

A bellows type fuel pump according to claim 6 is
A groove is formed in the guide hole of the embedded member along a direction in which the bellows expands and contracts. In the bellows-type fuel pump according to the sixth aspect, since the groove in the bellows expansion and contraction direction is formed in the guide hole of the buried member, even if the shaft moves up and down as the bellows expands and contracts, the shaft and the guide hole do not move. During this time, the fuel is discharged or flows from the groove. Therefore, the expansion and contraction movement of the bellows is not hindered by the fuel pressure loss in the guide hole, and the increase in the driving torque can be suppressed.

[0014]

According to the bellows type fuel pump according to the first aspect of the present invention, the torsional force on the bellows can be supported by the shaft, so that a large sliding motion does not occur between the drive mechanism and the movable end of the bellows. Even with the configuration, the durability of the bellows can be sufficiently ensured. As a result,
The conventional image sticking prevention roller can be eliminated, and downsizing and cost reduction can be realized.

According to the bellows type fuel pump according to the second aspect, since the torsional force on the bellows can be supported by the key and the key groove, a large sliding motion occurs between the drive mechanism and the movable end of the bellows. No configuration,
The durability of the bellows can be sufficiently ensured. As a result, the conventional image sticking prevention roller can be eliminated,
Size reduction and cost reduction can be realized.

According to the bellows type fuel pump, even if the shaft moves up and down as the bellows expands and contracts, the fuel between the shaft and the guide hole flows from the through hole to the outer peripheral portion of the embedded member. Since the bellows are discharged or flown in, the expansion and contraction movement of the bellows is not hindered by the fuel pressure loss in the guide hole, and an increase in the driving torque can be suppressed.

According to the bellows type fuel pump, even if the shaft moves up and down as the bellows expands and contracts, the fuel between the shaft and the guide hole flows from the through hole to the outer peripheral portion of the embedded member. Since the bellows are discharged or flown in, the expansion and contraction movement of the bellows is not hindered by the fuel pressure loss in the guide hole, and an increase in the driving torque can be suppressed. In addition, since the groove in the bellows expansion and contraction direction is formed on the outer peripheral portion of the embedded member, it is possible to supply sufficient fuel into the bellows while using wasted space in the bellows. Cost reduction can be realized.

According to the bellows type fuel pump according to the fifth aspect, even if the shaft moves up and down as the bellows expands and contracts, the fuel between the shaft and the guide hole is discharged or flows in from the groove. The expansion and contraction movement of the bellows is not hindered by the fuel pressure loss in the guide hole, and an increase in driving torque can be suppressed.

According to the bellows type fuel pump of the present invention, even if the shaft moves up and down as the bellows expands and contracts, the fuel between the shaft and the guide hole is discharged or inflow from the groove. The expansion and contraction movement of the bellows is not hindered by the fuel pressure loss in the guide hole, and an increase in driving torque can be suppressed.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall sectional view showing an embodiment of the present invention. Numeral 10 denotes a bellows type fuel pump used in a direct cylinder injection type spark ignition engine, and a fuel injection valve facing each cylinder. Pump fuel to

The fuel pump 10 includes a pump housing 11 connected to a cylinder head (not shown), a pump shaft 12 rotatably supported by the pump housing 11, and an axial cam 13 formed integrally with the pump shaft 12. And a plurality of bellows 20 that reciprocate following the axial cam 13.

Here, the expansion and contraction movement of the bellows 20 is driven via the axial cam 13 and the swash plate 32 rotatably connected with the bearing 35 interposed therebetween. The pump shaft 12 has an end engaged with a rear end of a camshaft (not shown) via a claw 14 or the like, and is configured to rotate together with the camshaft.

The fuel pump 10 draws fuel guided from a suction passage (low-pressure fuel supply passage) 21 by the bellows 20 extending with the rotation of the axial cam 13. The fuel discharged from the fuel pump is supplied at a regulated pressure through a low-pressure regulator.

In the fuel pump 10, the bellows 20 contracts with the rotation of the axial cam 13, so that the pressurized fuel is discharged from the discharge passage (high-pressure fuel supply passage) 2
2 and the fuel pumped from the discharge passage 22
After being adjusted to a predetermined pressure via a high-pressure regulator (not shown), the pressure is supplied to the fuel injection valve of each cylinder.

The bellows 20 has a cylindrical shape whose cross section is bent in a labyrinth shape, and is configured to be able to expand and contract in the axial direction. The fixed end of the bellows 20 is
And is fixed to the pump housing 11 side. That is, the annular member 23 is coupled to the fixed end of the bellows 20,
The annular member 23 is sandwiched between the blocks 24 and 25 provided in the pump housing 11. A seal ring 29 is interposed between the annular member 23 and the block 25.

On the other hand, the movable end of the bellows 20
It reciprocates following the axial cam 13 via the crown member 34 and the swash plate 32. That is, the driving mechanism according to the present invention for reciprocating the movable end of the bellows in the expansion and contraction direction is constituted by the crown member 34, the swash plate 32, the axial cam 13, and the like.

The crown member 34 is connected to the movable end of the bellows 20 via an annular member 33.
4 has a spherical surface, and comes into contact with the swash plate 32. On the back surface, a columnar shaft 60 is press-fitted. In particular, in the present embodiment, the center O of the shaft 60 is
₂ is offset from the center O ₁ of the crown member 34 and the bellows 20.

The swash plate 32 is connected to the axial cam 1 via a thrust bearing 35 and a radial bearing 36.
3 so as to be rotatable. Accordingly, when the axial cam 13 rotates, the crown member 34 reciprocates in the expansion and contraction direction via the swash plate 32, and the bellows 20 expands and contracts.

The internal space of the bellows 20 is
The pump chamber 40 has an inlet-side check valve 41.
And is connected to the discharge passage 22 via an outlet-side check valve 42. The block 25 includes a pump chamber 40 in the bellows 20.
An entrance 43 is formed which opens into
It is connected to the suction passage 21 via the inlet side check valve 41, and is connected to the discharge passage 22 via the outlet side check valve 42.

The inlet side check valve 41 includes a spring 44
Is seated on the valve seat 45 by the urging force of the above, and the valve opens for the fuel flowing into the pump chamber 40 from the suction passage 22 through the entrance 43. On the other hand, the outlet side check valve 42 is seated on the valve seat 45 by the urging force of the spring 46 and opens for the fuel flowing out of the pump chamber 40 through the inlet / outlet 43 to the discharge passage 22.

The buried member 50 is formed in a column shape having an outer diameter slightly smaller than the inner diameter of the bellows 20. The base end of the embedded member 50 is press-fitted into the block 25 and is fixed to the pump housing 11 side together with the annular member 23 which is a fixed end of the bellows 20.

The length of the embedded member 50 in the axial direction is such that the block 25 and the crown member 34 when the bellows 20 are most contracted.
It is formed slightly smaller than the distance between them. That is, as shown in FIG. 1, whenever the bellows 20 expands and contracts,
A gap is defined between the crown member 34 and the distal end surface of the buried member 50, and this gap constitutes the pump chamber 40 described above.

The buried member 50 has a communication passage 51 connecting both ends thereof. As shown in FIGS. 2 and 3, the communication passage 51 is defined between the bellows 20 by a single groove 57 formed on the outer peripheral surface of the embedded member 50. The communication passage 51 extends in the direction of expansion and contraction of the bellows 20, and has one end connected to the entrance 43 of the block 25 and the other end connected to the gap between the tip surface of the embedded member 50 and the crown member 43, that is, to the pump chamber 40. Are in communication.

As shown in FIG. 2, the embedding member 50 is provided with a knock pin 52 protruding from the base end surface thereof, while the block 25 is formed with a positioning hole (not shown) into which the knock pin 52 is fitted. Have been. The knock pin 52 and the positioning hole are provided offset from the center of the embedded member 50. Then, the offset knock pin 52 is fitted into the positioning hole of the block 25, thereby positioning the embedded member 50 in the rotation direction, and thereby the communication path 51 is located at a position where the communication path 51 communicates with the entrance 43 of the block 25. Will be retained.

With the embedded member 50 held at this position, a guide hole 61 is formed in the embedded member 50. The guide hole 61 is formed so that the shaft 60 press-fitted into the back surface of the crown member 34 can be inserted and the shaft 6
0 is inserted with a small gap so that it can be slid with the expansion and contraction movement of the bellows. In addition, at least one through hole 62 communicating with the outer surface of the embedded member 50 is formed near the lower surface of the guide hole 61.

Next, the operation will be described. In the fuel pump 10 according to the present embodiment, the bellows 20 is extended with the rotation of the axial cam 13, so that the suction passage 21 is opened by the inlet-side check valve 41, and the fuel flows from the suction passage 21 to the entrance 43 and the communication passage 51. , And is sucked into the expanding gap of the pump chamber 40.

In this fuel pump 10, when the pressure of the pump chamber 40 rises from the discharge passage 22 due to the bellows 20 contracting with the rotation of the axial cam 13, the outlet side tick valve 42 opens, and the pump chamber The fuel compressed in the gap of 40 flows out to the discharge passage 22 through the communication passage 51 and the entrance / exit 43, and is supplied from the discharge passage 22 to the fuel injection valve facing each cylinder.

At this time, the bellows 20 expands and contracts with the rotation of the axial cam 13.
Since the bellows 20 is made to expand and contract through the swash plate 32, a large sliding motion such as a cam drive without a roller does not occur on the contact surface between the swash plate 32 and the crown member 34. Therefore, no problem such as seizure or an increase in frictional force occurs on the contact surface between the swash plate 32 and the crown member 34.
Conventional rollers can be eliminated.

Although the bearing 35 is set in place of the conventional roller, the bellows driven by the bearing 35 and the swash plate 32 according to the present embodiment are smaller than the conventional bellows driving structure using a combination of a cam and a roller. The drive structure is more effective for downsizing the pump.

However, since the contact surface of the crown member 34 is spherical, the contact point between the swash plate 32 and the crown member 34 deviates from the central axis of the crown member 34 and the bellows 20, and the swash plate 3
When the bellows 20 is driven by 2, a moment to twist the bellows 20 acts.

However, in this embodiment, the shaft 60 press-fitted into the crown member 34 is integrated with the bellows 20 while being offset from the central axis of the bellows 20, so that the torsional moment acting on the crown member 34 is reduced. Is the shaft 6
0 is supported by the embedded member 50 fitted. Therefore, the bellows 20 itself can be prevented from being twisted, and the durability of the bellows 20 is ensured.

The fuel that has entered the guide hole 61 is
Since the shaft 60 is moved up and down by the vertical movement of the bellows 20 due to the expansion and contraction of the bellows 20, the expansion and contraction movement of the bellows 20 is not affected at all by the fuel pressure loss in the guide hole 61.

Further, the bellows type fuel pump of the present embodiment has the following effects in addition to the above-mentioned effects, as compared with the conventional pump having a large cavity inside the bellows. That is, since the bellows-type fuel pump 10 of the present embodiment has the embedded member 50 that fills a useless volume in the bellows 20, the pump chamber 4 generated as the bellows 20 expands and contracts.
The volume change rate of 0 becomes large. And pump room 4
Since the amount of fuel charged to zero is small, the amount of air bubbles generated from fuel in the pump chamber 40 during the suction stroke in which the bellows 20 extends is also reduced. Due to the decrease in the amount of bubbles generated in the pump chamber 40, the pressure drop in the pump chamber 40 caused by the extension of the bellows 20 increases, and the inlet-side check valve 41
The shortage of the amount of fuel sucked into the pump chamber 40 via the above is suppressed, and the desired pump discharge amount can be obtained.

Further, as the driving speed of the fuel pump 10 increases, the closing timing of the inlet side check valve 41 is suppressed from being delayed, and pressure fluctuation in the suction passage 21 can be prevented.

Further, since the inlet / outlet 43 and the pump chamber 40 communicate with each other through the communication path 51 connecting both ends of the buried member 50, the fuel passes through the communication path 51 from the inlet / outlet 43 as the pump chamber 40 expands and contracts. The fluid flows smoothly, and the pressure loss of the fuel pump 10 can be reduced.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

For example, FIG. 4 shows FIG. 1 of the above-described embodiment.
FIG. 4 is a diagram corresponding to a cross-sectional view taken along the line XX of FIG. 3, which is an embodiment in which a single groove 62 a is provided in a shaft 60 a instead of the through hole 62 in the embodiment (FIG. 3).
FIG. 5 is a view corresponding to a cross-sectional view taken along the line XX of FIG. 1. In the above-described embodiment (FIG. 3), a Groove 62
This is an embodiment in which b is provided.

In the bellows type fuel pump of the embodiment shown in FIG.
a, the shaft 60a and the guide hole 6
The fuel that has entered between them is discharged or flows in from the groove 62a. Also, in the bellows type fuel pump of the embodiment shown in FIG. 5, even if the shaft 60
The fuel that has entered between them is discharged or flows in from the groove 62b. Therefore, the expansion and contraction movement of the bellows 20 is not hindered by the fuel pressure loss in the guide hole 61, and the increase in the driving torque can be suppressed.

In the embodiment shown in FIGS.
In this embodiment, a key 63 is provided coaxially with the embedded member 50, a key 63 is provided on the shaft 60c, a key groove 64 is provided on the embedded member 50c, and a torsional moment to the bellows 20 is supported by the key 63. As in the embodiment shown in FIG. 1, the embedded member 50c and the shaft 60c can be connected to the key 63 without offsetting the central axes of the shaft 60 and the embedded member 50.
And the key groove 64 prevents the swash plate 3 from rotating.
The torsion moment to the bellows 20 when the bellows 20 expands and contracts due to the key 63 and the key groove 6
4 can be supported. Therefore, the durability of the bellows 20 can be sufficiently ensured, and as a result, the conventional anti-seizure roller can be eliminated, so that downsizing and cost reduction can be realized.

The embodiment shown in FIG. 6 is an example in which the through hole 62c is formed in the same manner as the embodiment shown in FIG.
And as shown in FIG. 8, as an alternative to the through hole 62c,
It is also possible to form the groove 62d or the groove 62e. These embodiments are appropriately used depending on various conditions such as the size of the pump and the efficiency of discharge and inflow of the fuel that has entered the guide hole 61.

[Brief description of the drawings]

FIG. 1 is an overall sectional view showing an embodiment of a bellows type fuel pump of the present invention.

FIG. 2 is an enlarged sectional view showing a bellows portion shown in FIG. 1;

FIG. 3 is a sectional view taken along line XX of FIG. 1;

FIG. 4 is a sectional view showing another embodiment of the bellows type fuel pump of the present invention, and is a sectional view corresponding to a sectional view taken along line XX of FIG.

5 is a sectional view showing still another embodiment of the bellows type fuel pump of the present invention, and is a sectional view corresponding to a sectional view taken along line XX of FIG. 1;

6 is a cross-sectional view showing still another embodiment of the bellows type fuel pump of the present invention, and is a cross-sectional view corresponding to a cross-sectional view taken along line XX of FIG.

7 is a cross-sectional view showing still another embodiment of the bellows type fuel pump of the present invention, and is a cross-sectional view corresponding to a cross-sectional view taken along line XX of FIG.

8 is a cross-sectional view showing still another embodiment of the bellows-type fuel pump of the present invention, and is a cross-sectional view corresponding to a cross-sectional view taken along line XX of FIG.

FIG. 9 is an overall sectional view showing a conventional bellows type fuel pump.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Bellows type fuel pump 11 ... Housing 13 ... Axial cam 20 ... Bellows 21 ... Suction passage 22 ... Discharge passage 32 ... Swash plate 34 ... Crown member 40 ... Pump chamber 41 ... Inlet side check valve 42 ... Outlet side check valve 43 ... Entrance 50 ... Buried member 60 ... Shaft 62 ... Through hole 63 ... Key 64 ... Key groove O ₁ ... Center axis of bellows O ₂ ... Center axis of shaft

Claims (6)

[Claims] An expandable tubular bellows, a housing for fixing a fixed end of the bellows, a drive mechanism for reciprocating a movable end of the bellows in an expanding and contracting direction, and a suction passage for guiding fuel to the bellows; An inlet-side check valve that opens for fuel flowing into the bellows from the suction passage, a discharge passage that discharges fuel from the bellows, and a valve that opens for fuel flowing from the bellows to the discharge passage. A bellows type fuel pump having an outlet side check valve, wherein a columnar embedded member is housed in the bellows, one end of the embedded member is fixed to the housing side, and the other end of the embedded member is connected to the bellows. And a guide hole is offset from the center of the bellows at the other end of the buried member, and a guide hole is formed in the guide hole on the bellows side. Bellows type fuel pump, characterized in that the insertion of the boss was shaft. 2. A telescopic tubular bellows, a housing for fixing a fixed end of the bellows, a drive mechanism for reciprocating a movable end of the bellows in a telescopic direction, and a suction passage for guiding fuel to the bellows; An inlet-side check valve that opens for fuel flowing into the bellows from the suction passage, a discharge passage that discharges fuel from the bellows, and a valve that opens for fuel flowing from the bellows to the discharge passage. A bellows type fuel pump having an outlet side check valve, wherein a columnar embedded member is housed in the bellows, one end of the embedded member is fixed to the housing side, and the other end of the embedded member is connected to the bellows. And a guide hole is drilled in the other end of the buried member, and a shaft fixed to the bellows side is inserted into the guide hole, and the guide is inserted. The embedded bellows type fuel pump, characterized in that the formation of the key and keyway to detent the shaft relative to member between said shaft and. 3. The bellows-type fuel pump according to claim 1, wherein a through hole is formed in the buried member so as to communicate an outer peripheral portion of the buried member with the guide hole. 4. A piercing hole is formed in the buried member to communicate an outer peripheral portion of the buried member with the guide hole.
3. The bellows type fuel pump according to claim 1, wherein a groove is formed in an outer peripheral portion of the embedded member along a direction in which the bellows expands and contracts. 5. The bellows type fuel pump according to claim 1, wherein a groove is formed in an outer peripheral portion of the shaft along a direction in which the bellows expands and contracts. 6. The bellows type fuel pump according to claim 1, wherein a groove is formed in the guide hole of the buried member along a direction in which the bellows expands and contracts.