JP2006105090A - Fuel pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel pump preventing local contact of a contact part and a cam surface due to inclination even if a cam surface is inclined when a cam pushes the contact part on a plunger side. <P>SOLUTION: A roller 30 driven and rotated by contacting a cam 33 and reciprocating a plunger 18 via a lifter 20 is arranged between the cam 33 and the plunger 18. The roller 30 is rotatably supported by a roller housing 25. The roller housing 25 is suspended and supported by a rocker shaft 26 in relation to the lifter 20. The rocker shaft 26 is arranged in a direction crossing a cam shaft 34 of the cam 33. Since the roller 30 is inclined in a same direction in parallel with the cam shaft 34 with accompanying inclination of the cam surface 33a of the cam 33 with this structure, local contact of the cam surface 33a and the roller surface 30a is prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel pump such as a high-pressure fuel pump that is mounted on, for example, an automobile engine and supplies fuel to a fuel injection valve or the like.

Conventionally, as a fuel pump mounted on an automobile engine or the like, for example, a plunger-type high-pressure pump disclosed in Patent Document 1 is known.
In the high-pressure pump 11 of Patent Document 1, as shown in FIG. 1, an elliptical drive cam 23 rotates, and the drive is transmitted to the bottom plate portion 18 a of the lifter 18 according to the phase of the drive cam 23. Yes. And the plunger 17 advanced to the pressurizing chamber 14 side via the lifter 18 compresses the fuel in the pressurizing chamber 14 and supplies it to the fuel injection valve of the engine. The drive cam 23 pushes the lifter 18 while always in line contact with the bottom plate portion 18a of the lifter 18 in the width direction.
JP 2001-295754 A

  However, for example, the cam shaft of the drive cam 23 is not exactly orthogonal to the advancing / retreating direction of the plunger 17, or the manufacturing accuracy of the drive cam 23 itself is low or accurate even if the cam shaft is arranged accurately. In some cases, the cam surface is not accurately orthogonal to the advancing and retreating direction of the plunger 17. If the drive cam 23 is out of alignment due to these, the drive cam 23 cannot make line contact with the bottom plate portion 18a of the lifter 18, and so-called one-side contact occurs. Such local contact of the cam surface may adversely affect the compression efficiency of the pump, cause abnormal noise, or increase the surface pressure of the contacted portion, which may cause uneven wear. It was.

  The present invention has been made paying attention to such problems existing in the prior art. The purpose of the fuel pump is to prevent the contact portion from locally contacting the cam surface due to the tilt even if the cam surface tilts when the cam pushes the contact portion on the plunger side. It is to provide.

In order to achieve the above object, the operation and effect will be described below.
According to the first aspect of the present invention, in the fuel pump that pressurizes and discharges the fuel by driving the plunger inserted into the cylinder so as to be slidable in a reciprocating manner with the cam, The gist of the invention is that it can be tilted in a direction parallel to the cam shaft of the cam as the contact surface tilts.

  If configured in this way, when cam alignment is out of order, that is, for example, the cam shaft is not exactly perpendicular to the plunger's advance / retreat direction, or even if the cam shaft is arranged accurately, it is driven. When the cam itself is not manufactured accurately or is not mounted correctly, and the cam tilts in the direction intersecting the cam shaft, the contact portion of the plunger on the cam is the surface of the portion where the cam contacts The pressure causes the cam to tilt following the tilt of the cam. Then, the contact area of a cam and a contact part increases, and the malfunction which arises by local contact will be eliminated. In short, while the plunger itself is accurately advanced and retracted so as not to be shaken, only the contact portion can be tilted in a direction parallel to the cam shaft so that the drive received from the cam is passively contacted by line contact as much as possible when the cam contact surface tilts. It is comprised as follows.

  Here, the contact portion corresponds to a lifter connected to the plunger main body as a part of the plunger that pressurizes the fuel, a roller that rotates in contact with the cam and is driven by the cam and reciprocates the plunger. .

  According to a second aspect of the invention, in addition to the configuration of the first aspect of the invention, the contact portion is a connecting portion connected to a plunger main body that pressurizes the fuel, and the connecting portion is connected to the cam of the cam. The gist of the invention is that the camshaft is supported by a rocking shaft arranged in a direction crossing the shaft so that the cam can be swung in a direction parallel to the camshaft of the cam. To do.

  According to the second aspect of the present invention, the connecting portion is swayed by swingably supporting the connecting portion as the contact portion connected to the plunger main body on the swing shaft arranged in the direction intersecting the cam shaft of the cam. Swing around the dynamic axis. As a result, the connecting portion can be tilted in a direction parallel to the cam shaft of the cam as the cam contact surface tilts. As a result, the contact area between the cam and the connecting portion increases, and problems caused by local contact are eliminated. Here, the connecting portion corresponds to, for example, a lifter.

In addition, it is preferable to arrange the cam shaft and the swing shaft so as to be orthogonal or substantially orthogonal since the contact resistance when the connecting portion follows the tilt of the cam is reduced.
Further, in the invention according to claim 3, in addition to the structure of the invention according to claim 1, the contact portion is a connecting portion connected to a plunger main body for pressurizing fuel, and the connecting portion is connected to the plunger. The gist of the invention is that they are connected via an elastic member and tilted in a direction parallel to the cam shaft of the cam as the contact surface of the cam tilts.

  In the invention according to claim 3, when an external force is received by connecting a connecting portion as a contact portion connected to the plunger body to the plunger via an elastic member, the plunger can be swung by its elasticity. . As a result, the connecting portion can be tilted in a direction parallel to the cam shaft of the cam as the contact surface of the cam tilts, and the contact area between the cam and the connecting portion increases, thereby eliminating problems caused by local contact. Will be.

  By restricting the direction of rocking here, it becomes easy to tilt as the contact surface of the cam tilts. For example, by arranging a plurality of elastic members along the direction intersecting the camshaft so that the rocking is performed along the direction parallel to the camshaft, free swinging of the contact portion is restricted, It is conceivable that a guide member is provided side by side so as to always tilt along one direction. Here, the connecting portion corresponds to, for example, a lifter.

  Further, in the invention according to claim 4, in addition to the configuration of the invention according to any one of claims 1 to 3, the cam and the plunger are in contact with the cam to rotate and follow the cam. A roller that reciprocates the plunger driven by the actuator is disposed, and the roller is supported by a swing shaft disposed in a direction intersecting the cam shaft of the cam so as to be able to swing, so that the contact surface of the cam can be tilted. Accordingly, the gist is that the cam is tilted in a direction parallel to the cam shaft.

  Further, in the invention according to claim 5, in addition to the configuration of the invention according to any one of claims 1 to 3, the cam and the plunger are in contact with the cam to rotate and follow the cam. A roller driven and reciprocatingly moved by the plunger, and supporting the roller via an elastic member with respect to the plunger in a direction parallel to the cam shaft of the cam as the cam contact surface tilts. The gist is that it is tilted.

  Here, when the plunger is directly driven by a cam without using a roller, a large sliding friction is generated when the cam surface comes into contact with the contact surface of the plunger, resulting in poor energy efficiency. However, the invention described in claims 4 and 5 employs a configuration in which a roller is disposed between the cam and the plunger so as to contact and rotate the cam and to be driven by the cam to reciprocate the plunger. As a result, sliding friction can be greatly reduced.

  However, since the cam surface and the roller are in a line contact state, when the cam or roller is misaligned, the contact surface pressure tends to be remarkably increased. That is, it is necessary to adjust the alignment of both the cam and the roller and to set the strength of the roller in consideration of the case where a large contact surface pressure is locally applied to the roller.

  Therefore, in the invention according to the fourth aspect, when a roller is provided between the cam and the plunger, the roller is swingably supported on a swing shaft disposed in a direction intersecting the cam shaft of the cam. . As a result, the roller swings around the swing shaft, and the roller can be tilted in a direction parallel to the cam shaft of the cam as the cam contact surface tilts. As a result, the contact area between the cam and the roller increases, and problems caused by local contact are eliminated. Further, it is preferable to arrange the cam shaft and the swing shaft so as to be orthogonal or substantially orthogonal, since the contact resistance when the roller follows the tilt of the cam is reduced.

  For this reason, in the invention described in claim 5, when a roller is disposed between the cam and the plunger, when the roller is connected to the plunger via an elastic member, an external force is received. Swing by elasticity. As a result, the contact portion can be tilted in a direction parallel to the cam shaft of the cam as the cam contact surface tilts, and the contact area between the cam and the roller is increased, thereby eliminating problems caused by local contact. The Rukoto.

  By restricting the direction of rocking here, it becomes easy to tilt as the contact surface of the cam tilts. For example, by arranging a plurality of elastic members along the direction intersecting the camshaft, restricting free swinging of the roller, or providing a guide member so that the roller always tilts along one direction Can be considered.

(Embodiment 1)
DESCRIPTION OF EMBODIMENTS Hereinafter, a first embodiment in which a fuel pump according to the present invention is embodied as a high-pressure fuel pump of an engine such as a cylinder injection engine will be described with reference to FIGS. 1 and 2, the illustration of the fuel supply passage, the electromagnetic spill valve that opens and closes the passage, the high-pressure fuel passage, the check valve provided in the passage, and the like are omitted.

  As shown in FIGS. 1 and 2, in the high pressure fuel pump 11, a cylinder 14 is disposed in a housing 13. A bracket 15 is attached to the lower end of the housing 13. A lifter guide 16 is disposed on the lower surface of the bracket 15. The lifter guide 16 is a kind of casing configured in a cylindrical shape, and a through hole 16a is formed in the center of the lower end surface, and a peripheral edge portion 16b surrounding the through hole 16a is formed.

  A cylinder support tube 17 is disposed at an inner peripheral upper position of the lifter guide 16. The cylinder 14 is placed on the cylinder support cylinder 17. A sliding hole 14a is formed at the center of the cylinder 14, and a plunger 18 is fitted into the sliding hole 14a so as to be slidable in the axial direction. An upper space defined by the plunger 18 in the cylinder 14 is a pressurizing chamber 19. A seal member 19 a is disposed in the protruding cylinder portion 14 b formed at the lower end of the cylinder 14. The seal member 19a prevents the fuel leaking from the pressurizing chamber 19 through the clearance of the plunger 18 and the sliding hole 14a from being mixed with the lubricating oil that has entered the lifter guide 16.

  A lifter 20 is installed in the lifter guide 16 and on the peripheral edge portion 16b. The lifter 20 is guided by the inner peripheral surface of the lifter guide 16 and can slide in the axial direction. As shown in FIG. 2, the base end portion (plunger base end portion) 18 a of the plunger 18 is in contact with the bottom plate portion (lifter bottom plate portion) 20 a of the lifter 20. A retainer 21 is engaged with the outer periphery of the base end of the plunger 18. A spring 22 is interposed between the retainer 21 and the cylinder support cylinder 17 in a compressed state. The plunger base end portion 18 a is pressed toward the lifter bottom plate portion 20 a by the urging force of the spring 22. Similarly, the lifter 20 is pressed against the upper surface of the peripheral edge portion 16 b of the lifter guide 16.

  An O-ring 24 for sealing is disposed between the housing 13 and the cylinder support cylinder 17, between the cylinder support cylinder 17 and the lifter guide 16, and between the lifter guide 16 and the bracket 15.

  A roller housing 25 is suspended and supported by a swing shaft 26 on the lifter bottom plate portion 20a. The upper body of the roller housing 25 extends from the through hole 16a into the lifter guide 16 (see FIG. 1). The upper half of the roller housing 25 is surrounded by the lifter bottom plate 20 a and the peripheral edge 16 b of the lifter guide 16. The upper body of the roller housing 25 has a clearance for its own swinging motion between the lifter bottom plate 20a and the peripheral edge 16b. The roller housing 25 can swing around the swing shaft 26 within a range that does not interfere with the lifter bottom plate portion 20a and the peripheral edge portion 16b.

  A rotation shaft 27 is fixed to the bearing arm 25 a of the roller housing 25. A roller 30 is mounted on the rotating shaft 27 via a rolling bearing 28. The surface of the roller 30 is a roller surface 30a. The swing shaft 26 and the rotation shaft 27 are disposed orthogonally in a plan view of the roller housing 25, and both the shafts 26 and 27 are disposed in parallel in a side view. The roller housing 25, the rotating shaft 27, and the roller 30 constitute a roller portion 31.

  A cam 33 is disposed below the roller portion 31. The cam 33 is rotated by a cam shaft 34 that is linked to an engine (not shown). The outer periphery of the cam 33 is a cam surface 33a. Three cam noses 33b (FIG. 1) are formed on the cam 33 at intervals of 120 degrees. The cam shaft 34 is disposed so as to be parallel to the rotation shaft 27 at a position below the rotation shaft 27. The cam surface 33a of the cam 33 is always in contact with the roller surface 30a of the roller 30. Since the axes of the cam shaft 34 and the rotating shaft 27 are arranged in parallel, the cam surface 33a is in line contact with the roller surface 30a in the width direction.

The operation of the high-pressure fuel pump 11 configured as described above will be described.
When the cam shaft 34 rotates and the cam 33 rotates as the engine is driven, the plunger 18 is reciprocated in the axial direction via the roller portion 31 and the lifter 20 according to the change in the phase of the cam surface 33a. The high-pressure fuel pump 11 changes the volume in the pressurizing chamber 19 by the operation of the plunger 18 to pressurize the fuel or suck the fuel as a premise of pressurization.

  More specifically, the pressurization and suction processes will be described. When the cam 33 is at a position where the intermediate portion of the two cam noses 33b presses the roller 30 (position shown in FIG. 1), the roller portion 31 and the lifter 20 move to the lowest position. At this time, the plunger 18 reaches the lowest position where the plunger 18 moves in the most retracted direction from the pressurizing chamber 19 in conjunction with the roller portion 31 and the lifter 20, and the volume of the pressurizing chamber 19 is maximum and is sucked. Fuel is introduced into the pressurizing chamber 19.

  From this state, for example, when the cam 33 is rotated counterclockwise in FIG. 1, the plunger 18 starts to rise through the roller portion 31 and the lifter 20, and the volume of the pressurizing chamber 19 is compressed and pressurized. The chamber 19 is gradually pressurized. When the cam nose 33b is in a position where the roller 30 is pressed, the roller portion 31 and the lifter 20 are moved to the highest position. At this time, the plunger 18 reaches the highest position that protrudes most into the pressurizing chamber 19 in conjunction with the roller portion 31 and the lifter 20, and the volume of the pressurizing chamber 19 is in the most compressed state. The pressurized high-pressure fuel reaches a high-pressure fuel passage (not shown) and is discharged by pushing a check valve provided in the passage.

  When the cam 33 is further rotated counterclockwise in FIG. 1, the plunger 18 starts to descend again. As the plunger 18 descends, fuel is sucked. In this way, the fuel is pressurized as the plunger 18 is raised, and the fuel is sucked again as the plunger 18 is lowered. The pressurization and the suction stroke are repeatedly performed by the rotation of the cam 33.

  Incidentally, it is originally planned that a straight line Q orthogonal to a straight line P passing through the axis of the camshaft coincides with the forward / backward direction of the plunger 18 as shown in FIG. However, for example, as shown in FIG. 3B, when the cam shaft 34 is not exactly perpendicular to the advancing and retreating direction of the plunger, the axis of the cam shaft 34 and the cam surface 33a are not parallel. The cam surface 33a may tilt. In the first embodiment, the roller portion 31 (roller housing 25) swings around the swing shaft 26 following the tilt of the cam surface 33a, in other words, tilts in a direction parallel to the cam shaft 34. Regardless of the tilt of the surface 33a, the cam surface 33a and the roller surface 30a are always in direct line contact with each other. Therefore, the cam surface 33a hardly comes into contact with the roller surface 30a. Regardless of the tilt of the cam surface 33 a, the roller surface 30 a passively applies the driving force from the cam 33 and pushes the plunger 18 through the lifter 20. In FIG. 3, the tilting of the cam surface 33a is slightly exaggerated.

According to the high pressure fuel pump 11 of the first embodiment described above, the following effects can be obtained.
(1) In the first embodiment, the cam surface 33a rotates even if the mounting accuracy of the cam 33 to the cam shaft 34 is poor or the manufacturing accuracy of the cam 33 itself is low and the cam shaft 34 is accurately arranged. Even if it is not parallel to the shaft 27, the roller portion 31 (roller housing 25) follows the tilt of the cam surface 33a, and the cam surface 33a and the roller surface 30a face each other. As a result, the cam surface 33a hardly comes into local contact with the roller surface 30a, causing an adverse effect on the compression efficiency of the high-pressure fuel pump 11, causing noise, or the cam surface 33a or the roller surface 30a. Various inconveniences such as uneven wear due to increased surface pressure of the contacted portion are eliminated.
(2) In the high-pressure fuel pump 11 of the first embodiment, the portion where the drive is directly transmitted is only a line contact portion where the curved surfaces of the cam surface 33a and the roller surface 30a abut. For this reason, when the alignment is deviated as described above, the contact surface pressure tends to be remarkably increased. In this regard, in the high pressure fuel pump 11 of the first embodiment, the roller portion 31 (roller housing 25) swings following the tilting of the cam surface 33a, and the cam surface 33a and the roller surface 30a face each other. It becomes. As a result, the contact surface pressure between the cam surface 33a and the roller surface 30a is hardly increased. Therefore, it is not necessary to unnecessarily increase the rigidity of the roller portion 31, which can contribute to cost reduction. .

(Embodiment 2)
Next, a second embodiment in which the high-pressure pump according to the present invention is embodied will be described based on FIG. 4 with a focus on differences from the first embodiment.

  As shown in FIG. 4, a bearing arm 42 is disposed below the lifter 40 via a coil spring 41 as a pair of left and right elastic members. That is, the bearing arm 42 is suspended and supported by the lifter 40 by the two coil springs 41. A rotating shaft 44 is provided between the bearing arms 42. A roller 46 is mounted on the rotation shaft 44 via a rolling bearing 45. The surface of the roller 46 is a roller surface 46a. The two coil springs 41 are arranged such that an imaginary line connecting the mounting positions on the lifter 40 side is substantially parallel to the rotation shaft 44.

  The cam 33 is disposed below the roller 46. The cam shaft 34 is disposed so as to be parallel to the rotation shaft 44 at a position below the rotation shaft 44. The cam surface 33a is always in contact with the roller surface 46a. Since the axes of the cam shaft 34 and the rotation shaft 44 are arranged in parallel, the cam surface 33a comes into line contact with the roller surface 46a in the width direction.

  With such a configuration, when the cam surface 33a tilts due to an alignment error, the coil spring 41 bends and the roller 46 swings following the tilt of the cam surface 33a. In other words, the cam shaft Therefore, the cam surface 33a and the roller surface 30a are always in direct line contact with each other. Therefore, the cam surface 33a hardly comes into local contact with the roller surface 30a, and the roller surface 30a passively passes the driving force from the cam 33 regardless of the tilt of the cam surface 33a.

Further, since the free swinging of the roller 46 is restricted by the pair of left and right coil springs 41, the roller 46 can more easily follow the tilting of the cam surface 33a.
(Embodiment 3)
Next, a third embodiment that embodies the high-pressure pump according to the present invention will be described based on FIGS. 5 to 7 with a focus on differences from the first and second embodiments.

  As shown in FIG. 6, a pair of left and right bearing arms 48 extending downward are fixed to the back surface of the lifter 20. A rotating shaft 49 is provided between the bearing arms 48. A roller 51 is mounted on the rotation shaft 49 via a rolling bearing 50. The surface of the roller 51 is a roller surface 51a. Two elongated holes 52 that are long in the vertical direction are formed at positions where the phase of the lifter 20 is 180 degrees out of phase. A circular pin hole 53 is formed at a position 180 degrees out of phase on the side surface of the lifter guide 16. The lifter 20 is arranged in the lifter guide 16 so that each elongated hole 52 of the lifter 20 faces each pin hole 53 of the lifter guide 16. As shown in FIG. 5, the lifter 20 is supported so as to be swingable with respect to the lifter guide 16 by inserting a pin 54 as a swinging shaft into both the holes 52 and 53. The pins 54 are arranged so that the axis thereof is orthogonal to the rotation shaft 49.

  In such a configuration, when the roller 51 is pushed by the rotation of the cam 33, the lifter 20 is moved up along the elongated hole 52, and the plunger is further moved up through the lifter 20. That is, the lifter 20 is supported by the lifter guide 16 by the pins 54 and the pins 54 slide in the elongated holes 52 so that the vertical movement based on the rotation of the cam 33 is allowed.

  When the cam surface 33a tilts due to an alignment error, the lifter 20 swings around the pin 54 as shown in FIG. 7, in other words, tilts in a direction parallel to the cam shaft 34. The roller 51 fixed to the lifter 20 also swings with the lifter 20. Accordingly, the cam surface 33a and the roller surface 51a are always in line contact with each other regardless of the tilt of the cam surface 33a, and the cam surface 33a hardly comes into local contact with the roller surface 51a. Regardless of the tilt of the cam surface 33a, the roller surface 51a passively passes the driving force from the cam 33 evenly.

(Other embodiments)
It should be noted that the present invention can be modified and embodied as follows.
In Embodiments 1 to 3, the roller is tilted in a direction parallel to the cam shaft. The roller tilting direction does not need to be set in a direction completely parallel to the cam shaft 34, so that the roller can be tilted following the tilting of the cam surface 33a due to the above-described misalignment. You may set in the direction slightly shifted from perfect parallel.

  -Embodiments 1-3 may be combined with each other. For example, the roller arm 31 may be swung as in the first embodiment and at the same time the bearing arm that supports the roller may be suspended by an elastic member as in the second embodiment. In the second embodiment, the coil spring 41 as an elastic member is disposed between the bearing arm 42 that supports the roller 46 and the lifter 40. Such a coil spring is applied to the lifter 20 in the third embodiment. It may be.

  In the second embodiment, the free swinging of the roller 46 is restricted using a pair of left and right coil springs 41 (that is, a plurality of elastic members), but the bearing arm 42 is surrounded on the lower back side of the lifter 40. The wall member as a guide may be provided to restrict the swinging. With such a guide, it is easy to restrict free swinging of the roller 46 using one elastic member.

-It is free to use means other than the coil spring 41 as the other elastic member.
・ A gasoline engine or a diesel engine may be used as an engine with a fuel pump.

  -Besides, it is free to implement in a mode that does not depart from the gist of the present invention.

1 is a partial cross-sectional front view of a high-pressure fuel pump according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line AA of FIG. 1 in the same first embodiment. In Embodiment 1, the tilting of the cam is described, (a) is an enlarged explanatory view of the main part in a state where it is not tilted, and (b) is an enlarged explanatory view of the main part in the tilted state. FIG. 4 is a partial cross-sectional view illustrating a main part of a high-pressure fuel pump according to a second embodiment. 9 is a cross-sectional view illustrating a state where a lifter is supported by a lifter guide in Embodiment 3. FIG. The lifter guide of Embodiment 3 and the side view of a lifter. Explanatory drawing explaining the state which the cam inclined in the high pressure fuel pump of Embodiment 3. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Fuel pump, 14 ... Cylinder, 18 ... Plunger as plunger main body, 20 ... Lifter as contact part and connection part, 26 ... Swing shaft, 30 ... Roller as contact part, 30a ... Roller surface as contact part , 33... Cam, 33 a... Cam surface as a contact surface of the cam, 34... Cam shaft, 40... Lifter as a contact portion and connecting portion, 41... Coil spring as an elastic member, 46. ... Roller surface as contact part, 51 ... Roller as contact part.

Claims (5)

In a fuel pump that pressurizes and discharges fuel by driving a plunger fitted in a cylinder so as to be slidable in a reciprocating manner,
A fuel pump characterized in that a contact portion of the plunger side with respect to the cam can be tilted in a direction parallel to a cam shaft of the cam as the contact surface of the cam tilts. The contact portion is a connecting portion connected to a plunger main body that pressurizes the fuel, and the connecting portion is swingably supported by a swing shaft disposed in a direction intersecting with the cam shaft of the cam. 2. The fuel pump according to claim 1, wherein the fuel pump is tilted in a direction parallel to the camshaft of the cam as the contact surface tilts. The contact portion is a connection portion connected to a plunger main body that pressurizes the fuel, and the connection portion is connected to the plunger via an elastic member, and the cam has a tilted contact surface. 2. The fuel pump according to claim 1, wherein the fuel pump is tilted in a direction parallel to the cam shaft. Between the cam and the plunger, a roller that contacts and rotates with the cam and is driven by the cam to reciprocate the plunger is disposed, and the roller is disposed in a direction intersecting the cam shaft of the cam. 4. The apparatus according to claim 1, wherein the cam is pivotably supported by the swing shaft and tilts in a direction parallel to the cam shaft of the cam as the contact surface of the cam tilts. The fuel pump described. A roller is disposed between the cam and the plunger so as to contact and rotate with the cam and to be driven by the cam to reciprocate the plunger. The roller is supported by an elastic member with respect to the plunger. The fuel pump according to any one of claims 1 to 3, wherein the fuel pump is tilted in a direction parallel to the cam shaft of the cam as the contact surface of the cam is tilted.

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