JP2010001828A - High pressure fuel pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inhibit or prevent a roller 53 and a cam 18 from unevenly wearing even if the roller 53 of a roller lifter 50 is inclined, in a plunger type high pressure fuel pump 4 for pressure-feeding fuel to a fuel injection valve 6 equipped on an engine. <P>SOLUTION: The roller lifter 50 receiving rotation of the cam 18, reciprocating and linearly displacing a plunger 23 is disposed at an outer end of the plunger 23. The roller 53 on which the cam is abutted is rotatably supported by a lifter body 51 of the roller lifter 50. A convex full crowning is formed on one of an outer circumference surface of the cam 18 and an outer circumference surface of the roller 53, and a concave full crowning having a shape corresponding to the convex full crowning is formed on another. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a plunger-type high-pressure fuel pump for pumping fuel to a fuel injection valve equipped in an engine.

  In recent years, various in-cylinder direct injection engines have been developed in which fuel is linearly injected into the combustion chamber of the engine. In the case of this in-cylinder direct injection engine, the fuel delivered from the fuel tank is introduced into the pressurizing chamber of a plunger type high pressure fuel pump, and the plunger of the high pressure fuel pump is linearly reciprocated by a cam to reciprocate the pressure. After pressurizing the fuel in the pressure chamber, it is stored in the delivery pipe, the high-pressure fuel in the delivery pipe is pumped to the fuel injection valve, and is injected directly from the fuel injection valve into the combustion chamber of the engine. (For example, refer to Patent Document 1).

  By the way, considering that the cam is in direct contact with the plunger, the tappet (corresponding to a roller lifter) is provided at the lower end of the plunger in consideration of sliding contact and increased friction loss. May be brought into rolling contact.

  In that case, when the base circle comes into contact with the cam roller and the plunger is lowered with the rotation of the cam, the fuel is sucked into the pressurizing chamber from the low pressure fuel pipe. On the other hand, when the cam nose of the cam contacts the cam roller and the plunger is raised, the volume of the pressurizing chamber is reduced.

By the way, the tappet body (corresponding to the lifter body) shown in Patent Document 1 is fixed to the wall portion by inserting both ends into a pair of opposing wall portions and an insertion hole formed in the pair of wall portions. The cam roller is externally mounted on the support shaft through a cylindrical bushing (slide bearing).
JP-A-5-332222

  In the structure shown in the conventional example according to Patent Document 1, it is ideal that the cam roller contact state with respect to the cam is in line contact with the cam roller rotation axis parallel to the cam rotation axis. However, when deflection occurs in the camshaft on which the cam is provided, a contact between the cam and the cam roller may occur, and uneven wear may occur in both of them.

  Therefore, the conventional example according to Patent Document 1 is configured to allow the inclination of the cam roller by forming a convex full crowning on the outer peripheral surface of the bushing attached to the support shaft. The convex full crowning has a shape like a “barrel” that gradually decreases in diameter from the axial center to both axial ends.

  In the configuration of the conventional example according to Patent Document 1, the cam roller can tilt with respect to the bushing attached to the support shaft. Therefore, when the cam shaft is deflected, the cam roller follows the cam shaft cam tilt. Therefore, it is described that the contact surface between the cam roller and the cam does not come into contact with each other.

  By the way, not only the deflection of the camshaft but also the cam roller may be inclined due to various factors. In such a case, the rotation axis of the cam roller is inclined with respect to the rotation axis of the cam. If the contact area becomes small and it is severe, point contact may occur. If it becomes so, the contact surface pressure of a cam roller will increase, and both will be easy to carry out partial wear.

  Incidentally, factors that cause the cam roller to incline include, for example, a play for preventing rotation of the tappet body with respect to the sliding hole of the housing, an attachment error of the support shaft that supports the cam roller, and the like.

  First, the play of the detent will be explained. The tappet main body is slidably inserted in the sliding hole of the housing along the vertical direction (axial direction of the sliding hole), and the tappet main body is prevented from rotating by the tappet guide.

  It is necessary to provide a circumferential play between the tappet guide and the tappet main body for smooth operation. For this reason, the rotation axis of the cam roller supported by the tappet main body is inclined with respect to the rotation axis of the cam. Sometimes. Specifically, such an inclination can be said to be an inclination in a plane orthogonal to the plane connecting the rotation axis of the cam roller and the rotation axis of the cam. This inclination is simply referred to as “lateral inclination”.

  Moreover, an attachment error will be described. In order to prevent the support shaft supporting the cam roller from slipping out into the insertion hole of the wall portion, a form in which both ends of the support shaft are fixed by caulking the pair of side walls may be employed. In that case, the support shaft may be inclined at the stage where both ends of the support shaft are caulked. It is difficult to make this inclination zero.

  The inclination of the cam roller due to such an attachment error is not only at least in the plane connecting the rotation axis of the cam roller and the rotation axis of the cam (simply referred to as “vertical inclination”), but orthogonal to the plane. It can be an inclination within a plane (simply referred to as “lateral inclination”) or a direction in which they are combined (simply referred to as a combined inclination).

  Such various inclinations of the cam roller are not considered at all in the conventional example according to Patent Document 1.

  That is, the camshaft deflection considered in the conventional example according to Patent Document 1 is considered to be similar to the above-described vertical inclination of the cam roller. The conventional example according to Document 1 is considered to exhibit a sufficient effect. However, it is not considered that the conventional example according to Patent Document 1 exhibits a sufficient effect with respect to the lateral inclination of the cam roller described above.

  In view of such circumstances, the present invention provides a plunger-type high-pressure fuel pump for pumping fuel to a fuel injection valve provided in an engine. Even if the roller of the roller lifter is inclined, the roller and the cam are offset. The object is to make it possible to suppress or prevent wear.

  The present invention is a plunger-type high-pressure fuel pump for pumping fuel to a fuel injection valve provided in an engine, and the plunger is reciprocally displaced linearly by the rotation of a cam at the outer end of the plunger. A convex full crowning is provided on either the outer peripheral surface of the cam or the outer peripheral surface of the roller that is rotatably supported by the lifter body of the roller lifter and is in contact with the cam. In the remaining other, concave full crowning having a shape corresponding to the convex full crowning is formed.

  A plunger type high-pressure fuel pump is generally driven by a cam attached to an intake cam shaft or an exhaust cam shaft of an engine to pressurize fuel supplied from a fuel tank and store it in a delivery pipe. The high pressure fuel in the delivery pipe is injected from the fuel injection valve into the combustion chamber or intake port of the engine.

  According to this configuration, even if the roller is inclined with respect to the cam in the vertical direction, the horizontal direction, or the direction in which they are combined, the roller is not in point contact with the cam but in line contact, The roller keeps rolling and cannot be dragged.

  As a result, it is possible to suppress or prevent a local increase in the contact surface pressure between the roller and the cam, thereby suppressing or preventing uneven wear of the roller and the cam.

  Preferably, the lifter body has a pair of opposing wall portions and a support shaft fixed to the wall portion by stamping by inserting both ends into insertion holes formed in the pair of wall portions. The roller is externally mounted on the support shaft via a plurality of rollers.

  In this configuration, the configuration of the roller lifter is specified, and the configuration in which the roller is supported by rolling is specified. In this way, when the support shaft is fixed to the pair of wall portions by stamping, the mounting shaft is tilted in the vertical direction, the horizontal direction or the direction in which they are combined at the stamping stage. Can occur.

  Even if such an attachment error occurs, if the concave crowning and the convex crowning are formed on the cam and the roller as described above, they are kept in a line contact state.

  Preferably, the lifter body is accommodated in the guide hole of the lifter guide so as to be slidable and prevented from rotating along the axial center of the hole. The lifter guide is provided separately or integrally with, for example, a cam housing attached to the cylinder head, a cylinder head, or the like.

  In this configuration, if there is play in the non-rotating structure, the lifter body can move slightly in the rotational direction within the guide hole of the pump body. Will be inclined to. Even in such a case, if the concave crowning and the convex crowning are formed on the cam and the roller as described above, their contact is maintained in a line contact state.

  According to the present invention, in a plunger-type high-pressure fuel pump for pumping fuel to a fuel injection valve mounted on an engine, even if the roller lifter is inclined, the contact surface pressure between the roller and the cam is locally increased. Therefore, it is possible to suppress or prevent the roller and cam from being unevenly worn. Therefore, it is advantageous in improving the durability of the roller and the cam.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

  First, FIG. 1 to FIG. 7 show an embodiment of the present invention. Prior to the description of the features of the present invention, a schematic configuration of a fuel supply system used in an in-cylinder direct injection type (in-cylinder direct injection type) engine to which the present invention is applied will be described with reference to FIG.

  As shown in FIG. 1, this fuel supply system mainly includes a fuel tank 1, a feed pump 2, a pressure regulator 3, a high pressure fuel pump 4, a delivery pipe (accumulation container) 5, a fuel injection valve 6, a low pressure fuel pipe 7, Including high-pressure fuel pipe 8 and return pipe 9.

  The feed pump 2 feeds fuel from the fuel tank 1. The pressure regulator 3 returns the fuel in the low-pressure fuel pipe 7 to a predetermined pressure or less by returning the fuel in the low-pressure fuel pipe 7 to the fuel tank 1 when the fuel pressure in the low-pressure fuel pipe 7 exceeds a predetermined pressure. To maintain.

  The high-pressure fuel pump 4 pressurizes the fuel sent out by the feed pump 2 and filtered by the filter 10 and stores it in the delivery pipe 5. The configuration of the high-pressure fuel pump 4 will be described later.

  The delivery pipe 5 supplies high-pressure fuel stored therein to the fuel injection valve 6. The fuel injection valve 6 directly injects the high-pressure fuel in the delivery pipe 5 into each combustion chamber of an engine (not shown). The number of fuel injection valves 6 is the same as the number of cylinders of the engine. For example, when six fuel injection valves 6 are used as shown in the drawing, for example, a six-cylinder engine is used.

  A return pipe 9 is connected to the delivery pipe 5 via a relief valve 11. The relief valve 11 is opened when the fuel pressure in the delivery pipe 5 exceeds a predetermined pressure, and a part of the fuel stored in the delivery pipe 5 is returned to the fuel tank 1 through the return pipe 9. The fuel pressure in the delivery pipe 5 is prevented from excessively rising.

  The low pressure fuel pipe 7 is provided with a pulsation damper 12. The pulsation damper 12 suppresses fuel pressure pulsation in the low pressure fuel pipe 7 when the high pressure fuel pump 4 is operated.

  Next, a specific configuration of the high-pressure fuel pump 4 will be described with reference to FIG.

  The high-pressure fuel pump 4 is generally of a known plunger type, and mainly includes a pump unit 20, an electromagnetic spill valve 30, a check valve 40, and a roller lifter 50.

  The pump unit 20 mainly includes a cylinder 21, a pressurizing chamber 22, and a plunger 23.

  The cylinder 21 is provided with a guide hole 21a of the plunger 23 along the vertical direction. The pressurizing chamber 22 is provided on the upper end side of the guide hole 21a, and is communicated with the feed pump 2 through the low-pressure fuel pipe 7 and delivered via the high-pressure fuel pipe 8 as shown in FIG. It communicates with the pipe 5. The plunger 23 is formed of a substantially cylindrical member, and is inserted into the guide hole 21a of the cylinder 21 so as to be slidable up and down.

  As an operation of the pump unit 20, the plunger 23 is reciprocated in the vertical direction in the cylinder 21 by the rotating cam 18, and the volume of the pressurizing chamber 22 is expanded or reduced. The fuel leaking from the fitting gap between the plunger 23 and the guide hole 21 a is accumulated in the fuel storage chamber 26 at the upper part of the seal unit 25, but is discharged to the return pipe 9 through the fuel discharge pipe 13. It has become.

  The electromagnetic spill valve 30 is provided above the pump unit 20 and controls communication between the low-pressure fuel pipe 7 and the pressurizing chamber 22 by controlling energization to the electromagnetic solenoid 31.

  The electromagnetic spill valve 30 mainly includes an electromagnetic solenoid 31, a bobbin 32, a core 33, an armature 34, a poppet valve 35, a seat body 36, and a compression coil spring 37.

  As an operation of the electromagnetic solenoid 31, when energization to the electromagnetic solenoid 41 is stopped, the poppet valve 35 opens the through hole of the seat body 36 by the expansion restoring force of the compression coil spring 37, and the low pressure fuel pipe 7 and the pressurizing chamber 22 are communicated (valve open state). On the other hand, when the electromagnetic solenoid 31 is energized, the armature 34 moves toward the core 33 so as to compress the compression coil spring 37, so that the poppet valve 45 closes the through hole of the seat body 46, and the low-pressure fuel pipe 7 The pressurizing chamber 22 is shut off (closed state).

  The check valve 40 prevents the fuel discharged from the high-pressure fuel pump 4 from flowing backward, and mainly includes a valve body 41, a seat body 42, a valve body 43, and a compression coil spring 44. .

  The operation of the check valve 40 is that the valve body 43 resists the urging force of the compression coil spring 44 when the pressure of the fuel pumped from the pressurizing chamber 22 through the high pressure fuel passage 21 b exceeds a predetermined value. Then, the check valve 40 is opened by being displaced away from the seat body 42, and the high-pressure fuel fed from the high-pressure fuel passage 21 b is supplied to the delivery pipe 5 through the high-pressure fuel pipe 8. It has come to be.

  The roller lifter 50 converts the rotary motion of the cam 18 into a linear motion and transmits it to the plunger 23 to displace the plunger 23 up and down, and mainly includes a lifter body 51, a support shaft 52, and a roller 53. It is configured.

  The lifter body 51 is inserted into the guide hole 56a of the lifter guide 56 so as to be able to reciprocate along the central axis. The lifter guide 56 is provided separately or integrally with, for example, a cam housing (not shown) for supporting the intake camshaft (or exhaust camshaft) 14.

  The lifter body 51 is formed in a substantially cylindrical shape, and is provided with a partition wall 51a that bisects vertically in the middle of the vertical direction. The upper peripheral wall 51b is above the partition wall 51a, and the lower peripheral wall 51c is below the partition wall 51a. It is said. The lower end of the plunger 23 is in contact with the upper surface of the partition wall 51 a of the lifter body 51 via the retainer 27. A roller 53 is rotatably supported on the lower peripheral wall 51 c of the lifter body 51 via a support shaft 52.

  And in the area | region which opposes 180 degree | times on the outer peripheral surface of the lifter body 51, the mutually parallel flat surfaces 51d and 51e are provided over the longitudinal direction (up-down direction) full length, and, thereby, radial cross-sectional shape is oval. Is formed.

  The reason why the two flat surfaces 51d and 51e are provided is that the lifter body 51 is prevented from rotating around the central axis of the guide hole 56a when the lifter body 51 is reciprocally displaced in the guide hole 56a of the lifter guide 56. Because.

  The structure of this detent will be described with reference to FIGS. That is, the pin hole 56b is provided in the peripheral wall portion of the lifter guide 56 along the tangential direction of the guide hole 56a. An axially intermediate portion of the pin hole 56b is opened so as to communicate with the guide hole 56a. When the anti-rotation pin 57 is mounted in such a pin hole 56b, a part of the anti-rotation pin 57 protrudes into the guide hole 56a, and the protruding portion abuts against one flat surface 51d of the lifter body 51. As a result, the lifter body 51 is prevented from rotating.

  The both ends of the support shaft 52 are fixed to the insertion holes 51f and 51g formed through the flat surfaces 51d and 51e of the lower peripheral wall 51c. With respect to the retaining of the support shaft 52, both ends of the support shaft 52 are clearance fitted into the insertion holes 51f and 51g, so that both ends of the support shaft 52 are stamped and squeezed. Both ends of 52 are expanded so that they do not come out of the insertion holes 51f and 51g.

  Although not shown in the drawings, the stamping operation for the support shaft 52 is performed by pressing and applying pressure to the both ends of the support shaft 52 inserted into the insertion holes 51f and 51g. The embossed grooves 52a and 52a are formed to generate a plastic flow in the radial direction and expand both ends of the support shaft 52. Thereby, the support shaft 52 is fixed in a state in which it is prevented from rotating on the lower peripheral wall 51c.

  The roller 53 is rotatably supported on the outer diameter side of the support shaft 52 via a plurality of rollers 54. The cam 18 is brought into contact with the outer peripheral surface of the roller 53 protruding outward. In order to press the roller 53 against the cam 18, a compression coil spring 55 is interposed between the partition wall 51 a of the lifter body 51 and the cylinder 21 in a compressed state. That is, the roller 53 is brought into pressure contact with the cam 18 by the expansion restoring force of the compression coil spring 55. The lubricating oil can be supplied to the contact portion between the roller 53 and the cam 18.

  Next, the operation of the high pressure fuel pump 4 will be described.

  In this embodiment, the high-pressure fuel pump 4 is driven by a cam 18 provided separately or integrally with an intake camshaft (or exhaust camshaft) 14 of the engine, for example.

  For example, in the case of a six-cylinder engine, a total of six fuel injections are performed once from the fuel injection valve 6 provided in each cylinder during one cycle of the engine, that is, while the crankshaft rotates twice. become. Further, for each cycle of the engine, the intake camshaft 14 rotates once, and the discharge operation from the high-pressure fuel pump 4 is performed three times. For this purpose, the cam 18 is provided with three cam noses 18a... With an angular interval of 120 ° around the rotation axis.

  That is, when the cam nose 18a pushes up the roller 53 of the roller lifter 50 due to the rotation of the cam 18 accompanying the engine operation, the plunger 23 of the pump unit 20 rises, and the compression coil spring 55 is compressed and the pressurizing chamber 22 is compressed. The volume of is reduced. On the other hand, when the cam nose 18a... Is separated from the roller 53 of the roller lifter 50 and comes into contact with the base circle, the roller lifter 50 and the plunger 23 are lowered by the expansion restoring force of the compression coil spring 55, and the volume of the pressurizing chamber 22 is increased. Is done.

  Therefore, first, during the period in which the contact position between the cam 18 and the roller 53 shifts from the apex of the cam nose 18a... Of the cam 18 to the base circle, the volume of the pressurizing chamber 22 is increased by lowering the plunger 23. Therefore, during that period, by stopping energization of the electromagnetic spill valve 30 to the electromagnetic solenoid 31, the electromagnetic spill valve 30 is opened by the expansion restoring force of the compression coil spring 37, and the low pressure fuel pipe is opened. 7 and the pressurizing chamber 22 communicate with each other, the fuel delivered from the feed pump 2 is sucked into the pressurizing chamber 22 through the low-pressure fuel pipe 7 (intake stroke).

  On the other hand, the volume of the pressure chamber 22 is reduced by raising the plunger 23 during the period in which the contact position between the cam 18 and the roller 53 is shifted from the base circle of the cam 18 to the apex of the cam nose 18a. Therefore, during that period, the electromagnetic solenoid 31 is energized to close the poppet valve 35 against the elastic force of the compression coil spring 37, and the low pressure fuel pipe 7 and the pressurizing chamber 22 are closed. Is cut off, the fuel pressure in the pressurizing chamber 22 rises, and when the fuel pressure reaches a predetermined value, the check valve 40 is opened and high-pressure fuel passes through the high-pressure fuel pipe 8 to deliver the delivery pipe 5. It is discharged toward (pressure increase process).

  Next, with reference to FIG. 3 to FIG. 7, a portion to which the features of the present invention are applied will be described in detail. 3 is a side view of the roller lifter 50 of the high-pressure fuel pump 4 shown in FIG. 2, and FIG. 4 is a cross-sectional view taken along line (4)-(4) of FIG. 3 and around the lifter body 51 of the roller lifter 50. A stop structure is shown. FIG. 5 is a plan view schematically showing a contact state of the roller 53 with respect to the cam 18 in an appropriate posture.

  In short, the convex full crowning and the concave full crowning that match each other are provided separately on the outer peripheral surface of the cam 18 and the outer peripheral surface of the roller 53 of the roller lifter 50.

  Specifically, in this embodiment, a convex full crowning is formed on the outer peripheral surface of the cam 18, and a concave full crowning having a shape matching the convex full crowning is formed on the outer peripheral surface of the roller 53.

  The full crowning is formed over the entire axial length of the outer peripheral surface to be formed, as is generally known. Further, the convex full crowning has a shape like a “barrel” that gradually decreases in diameter from the center in the axial direction toward the both ends in the axial direction of the outer peripheral surface of the cylinder (cam 18 or roller 53) to be formed. . On the other hand, the concave full crowning is a “drum” shape that gradually decreases in diameter from both axial ends of the outer peripheral surface of the cylinder (roller 53 or cam 18) to be formed toward the center in the axial direction. is there.

  In this embodiment, the convex full crowning and the concave full crowning have, for example, an arc shape having a single radius of curvature. 3 to 7, the full crowning shape is exaggerated.

  In addition, the full crowning can be a pseudo-logarithmic curve having a large radius of curvature in the middle in the axial direction and a radius of curvature that decreases toward the both ends in the axial direction (see, for example, JP-A-2003-106111). . Further, the full crowning can be formed into a complex curved surface shape in which a plurality of arcs of curvature radii are connected (see, for example, JP-A-2002-039326).

  For reference, for example, when the composite curved surface shape is a combination of three curved surfaces, the radius of curvature over a wide range in the axial direction of the cam 18 or the roller 53 is increased so that the cam 18 or the roller 53 has axially opposite ends. It is possible to reduce the radius of curvature and make the shape smoothly connect them.

  As described above, in the embodiment to which the features of the present invention are applied, the concave and convex full crowning that matches each other is provided on the outer peripheral surface of the cam 18 and the outer peripheral surface of the roller 53 of the roller lifter 50.

  In this case, if the cam 18 and the roller 53 are in an appropriate posture, the contact state is a line contact along the rotation axis O1 of the cam 18 and the rotation axis O2 of the roller 53.

  Moreover, even when the roller 53 is tilted, the contact state of the roller 53 with respect to the cam 18 is maintained in line contact without being point contact due to uneven full crowning. As a result, the roller 53 maintains the rolling state and is not dragged.

  As a result, it is possible to suppress or prevent a local increase in the contact surface pressure between the roller 53 and the cam 18, and thus it is possible to suppress or prevent uneven wear of the roller 53 and the cam 18. Etc., which is advantageous in improving their durability.

  By the way, as described above in the conventional example, the reason why the roller 53 is inclined is, for example, play for preventing the lifter body 51 from rotating with respect to the guide hole 56 a of the lifter guide 56, and the support shaft 52 that supports the roller 53. An attachment error etc. are mentioned.

  First, the play of the detent will be explained. The lifter body 51 is inserted into the guide hole 56a of the lifter guide 56 so as to be slidable in the vertical direction (the axial center direction of the guide hole 56a), and the lifter body 51 is prevented from rotating by the rotation prevention pin 57.

  In this case, it is necessary to provide a slight gap (play) between the one flat surface 51d of the lifter body 51 and the rotation prevention pin 57 for smooth operation. Therefore, for example, as shown in FIG. 6, the rotation axis O2 of the roller 53 supported by the lifter body 51 may be inclined by a predetermined angle α with respect to the rotation axis O1 of the cam 18. This inclination can be said to be an inclination in a plane orthogonal to the plane connecting the rotation axis O2 of the roller 53 and the rotation axis O1 of the cam 18, but in addition, both ends of the roller 53 in the axial direction are front and rear in the circumferential direction of the cam 18. It can also be said to be tilted. This inclination is simply referred to as “lateral inclination”.

  Next, an attachment error will be described. In order to prevent the support shaft 52 supporting the roller 53 from slipping out into the insertion holes 51f and 51g of the lower peripheral wall 51c, a form in which both ends of the support shaft 52 are stamped may be employed.

  In that case, it is possible that the support shaft 52 is inclined at the stage of stamping both ends of the support shaft 52. It is difficult to make this inclination zero.

  As the inclination of the roller 53 due to such an attachment error, for example, as shown in FIG. 7, there is an inclination in a plane connecting the rotation axis O <b> 2 of the roller 53 and the rotation axis O <b> 1 of the cam 18. In other words, this inclination is a state in which both axial ends of the roller 53 are inclined at a predetermined angle β in the vertical direction. The inclination angle β is the inclination of the rotation axis O2 of the roller 53 with respect to the straight line L parallel to the rotation axis O1 of the cam 18. This inclination is simply referred to as “vertical inclination”. In addition to the above, the inclination of the roller 53 due to the mounting error may be an inclination in a plane orthogonal to the plane connecting the rotation axis O2 of the roller 53 and the rotation axis O1 of the cam 18 (simply “horizontal”). There is an inclination in a direction (referred to simply as a combined inclination) in which the vertical inclination and the horizontal inclination are combined.

  By the way, since the cam 18 having the convex full crowning formed on the outer peripheral surface and the roller 53 having the concave full crowning formed on the outer peripheral surface are fitted, the aligning action between the cam 18 and the roller 53 is generated. Therefore, it can be said that the roller 53 is less likely to be inclined in the lateral direction. This makes it possible to provide a gap between the rotation prevention pin 57 and the one flat surface 51d of the lifter body 51.

  However, the rotation of the lifter body 51 may be made as small as possible by closely contacting the non-rotating pin 57 and the one flat surface 51d of the lifter body 51 without any gap. This is preferable because the lateral inclination of the support shaft 52 and the roller 53 attached to the lifter body 51 can be made as small as possible.

  However, when the non-rotating pin 57 and the one flat surface 51d of the lifter body 51 are in close contact with each other without a gap, the non-rotating pin 57 is inserted into the pin hole in order to reciprocate the lifter body 51 in the guide hole 56a with less resistance. It can be said that it is preferable to insert the rotary member 56b in a rotatable manner. By doing so, when the lifter body 51 is reciprocated up and down, the rotation-preventing pin 57 rotates, so that the movement of the lifter body 51 can be prevented.

  In addition, this invention is not limited only to the said embodiment, All the deformation | transformation and application included in the range equivalent to the claim and the said range are possible. Examples are given below.

  (1) In the above embodiment, an in-cylinder direct injection type six-cylinder engine is taken as an example, but the number of cylinders of the engine is arbitrary, and the present invention is applied to any gasoline engine or diesel engine. Is possible.

  (2) In the above embodiment, the roller 54 is interposed between the support shaft 52 and the roller 53 of the roller lifter 50 as an example. Instead of the roller 54, a slide bearing such as a cylindrical bush is used. It is also possible to intervene.

  (3) In the above embodiment, an example in which a convex full crowning is formed on the outer peripheral surface of the cam 18 and a concave full crowning is formed on the outer peripheral surface of the roller 53 is shown. For example, as shown in FIG. In other words, the concave full crowning can be formed on the outer peripheral surface of the cam 18 and the convex full crowning can be formed on the outer peripheral surface of the roller 53.

  (4) In the above embodiment, an example in which the cam 18 for driving the high-pressure fuel pump 4 is provided on the intake camshaft (or the exhaust camshaft) 14 is described. It can be independent of the operating state.

It is a figure which shows schematic structure of the fuel supply system used as the use object of the high pressure fuel pump which concerns on this invention. It is sectional drawing which shows the high pressure fuel pump of FIG. It is a figure which shows the roller lifter of the high pressure fuel pump shown in FIG. 2 from a side surface. FIG. 4 is a cross-sectional view taken along the line (4)-(4) in FIG. It is a top view which shows typically the contact state in the suitable attitude | position of the roller with respect to a cam. It is a top view which shows typically the horizontal direction inclination of a roller in FIG. It is a front view which shows typically the vertical direction inclination of a roller with respect to a cam. FIG. 4 is a view corresponding to FIG. 3 in another embodiment of the roller lifter of the high-pressure fuel pump according to the present invention.

Explanation of symbols

1 Fuel tank
4 High-pressure fuel pump
6 Fuel injection valve
18 cams
18a cam nose
20 Pump part
21 Pump cylinder
22 Pressurization chamber of pump part
23 Plunger
50 Roller lifter
51 Lifter body
51c Lower peripheral wall of lifter body 51f, 51g Insertion hole in lower peripheral wall
52 Spindle
53 Laura

Claims (3)

A plunger-type high-pressure fuel pump for pumping fuel to a fuel injection valve mounted on an engine,
A roller lifter is provided at the outer end of the plunger to linearly reciprocate the plunger in response to rotation of a cam.
Convex full crowning is provided on one of the outer peripheral surface of the cam and the outer peripheral surface of the roller that is rotatably supported by the lifter body of the roller lifter and is in contact with the cam. The high-pressure fuel pump is characterized in that a concave full crowning having a shape corresponding to the full crowning is formed. The high-pressure fuel pump according to claim 1,
The lifter body has a pair of opposed wall portions, and a support shaft fixed to the wall portion by stamping by inserting both end portions into insertion holes formed in the pair of wall portions,
The high-pressure fuel pump, wherein the roller is externally mounted on the support shaft via a plurality of rollers. The high-pressure fuel pump according to claim 1 or 2,
The high-pressure fuel pump, wherein the lifter body is housed in a guide hole of the lifter guide so as to be slidable and prevented from rotating along the axial center of the hole.

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