JP2010037985A - Fuel pump and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent uneven contact of a roller to a cam at low cost in a fuel pump reciprocating a plunger by reciprocating a lifter with a roller in a lifter guide. <P>SOLUTION: This invention relates to a method for manufacturing a fuel pump including a first lift guide 102 including a guide surface 102a guiding a lifter in a direction perpendicular to a cam surface 203a, and a second lifter guide 103 fixing and supporting an outer circumference surface 102b of the first lift guide 102. A perpendicularity calibration jig 300 including a slid finger 301 is used. The slid finger 301 includes a surface 301a along the guide surface 102a of the first lifter guide 102 and a cam contact surface 301b perpendicular to the same. The slid finger 301 is fitted along the guide surface 102a in the first lift guide and the cam contact surface 301b is arranged along the cam surface 203a, and adhesive 109 is filled between the first lifter guide 102 and the second lifter guide 103. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel pump that supplies fuel to a fuel injection valve of an internal combustion engine such as an engine, and a method for manufacturing the same.

  Conventionally, a plunger-type high-pressure fuel pump is known as a fuel pump mounted on an automobile engine.

  For example, in a plunger-type high-pressure fuel pump disclosed in Patent Document 1, the cam rotates as the engine is driven, and the plunger reciprocates in the axial direction in accordance with a change in the phase of the cam surface of the cam. . Then, the volume of the pressurizing chamber provided at the plunger end is changed by the operation of the plunger to pressurize the fuel or to suck the fuel as a premise of pressurization.

  A roller and a lifter are interposed between the cam and the plunger. The roller reciprocates along the cam surface, and the lifter and plunger connected to the roller also reciprocate together with the roller.

In the high-pressure fuel pump, the lifter is provided so as to reciprocate in the lifter guide. However, the lifter guide mounting portion (in Patent Document 1 in the state where the lifter guide is inclined with respect to the original installation position due to an installation error or the like). It is sometimes called “bracket”.) In this case, although the movement direction of the lifter within the lifter guide is not orthogonal to the cam surface, the roller is provided so as to be swingable with respect to the lifter via the swing shaft. The hit is prevented.
JP 2006-105090 A

  However, in the high-pressure fuel pump disclosed in Patent Document 1, since the roller is swingably provided via the swing shaft with respect to the lifter that slides in the lifter guide, the structure becomes complicated, There is a problem of high costs.

  The present invention has been made in view of the above problems, and in a fuel pump in which a plunger is reciprocated by reciprocating a lifter with a roller that rolls on a cam within a lifter guide, the roller relative to the cam is provided. It is an object of the present invention to provide a fuel pump and a method of manufacturing the same that can prevent per-piece contact at a low cost.

  As means for solving the above-described problems, the fuel pump of the present invention is configured as follows. That is, a fuel pump according to the present invention includes a plunger that is fitted in a cylinder so as to be reciprocally slidable, a lifter that has a roller that rolls along a cam surface of the cam, and a cam surface of the cam. A lifter guide that guides the lifter in a direction orthogonal to the above, and assuming that the plunger rotates and reciprocates through the lifter as the cam rotates to discharge fuel under pressure. Yes. The lifter guide includes a first lifter guide having a guide surface for guiding the lifter in the direction, and a second lifter guide for fixing and supporting the outer peripheral surface of the first lifter guide, The outer peripheral surface of one lifter guide is fixed to the fixing surface of the second lifter guide via an adhesive.

  According to the fuel pump having such a configuration, since the outer peripheral surface of the first lifter guide is fixed to the fixing surface of the second lifter guide via the adhesive, the first lifter is set before the adhesive is cured. The lifter guide direction by the guide can be adjusted so as to be directed in a direction perpendicular to the cam surface, and as a result, it is possible to prevent the roller from coming into contact with the cam surface. And the said adjustment can be performed at low cost.

  Moreover, the fuel pump of the present invention may be configured as follows. That is, a fuel pump according to the present invention includes a plunger that is fitted in a cylinder so as to be reciprocally slidable, a lifter that has a roller that rolls along a cam surface of the cam, and a cam surface of the cam. A lifter guide that guides the lifter in a direction orthogonal to the above, and assuming that the plunger rotates and reciprocates through the lifter as the cam rotates to discharge fuel under pressure. Yes. The lifter guide includes a first lifter guide having a guide surface for guiding the lifter in the direction, and a second lifter guide for fixing and supporting the outer peripheral surface of the first lifter guide, The outer peripheral surface of one lifter guide is fixed to the fixed surface of the second lifter guide via an elastic body.

  According to the fuel pump having such a configuration, even if the lifter guide direction by the guide surface of the first lifter guide is inclined without being orthogonal to the cam surface, a load exceeding a certain level is applied to the lifter. By acting in the cam direction (direction perpendicular to the cam surface), the elastic body provided between the outer peripheral surface of the first lifter guide and the fixed surface of the second lifter guide is deformed. As a result, the roller is pressed along the cam surface by the lifter, and the roller is prevented from coming into contact with the cam surface. In addition, since the elastic body can be provided between the outer peripheral surface of the first lifter guide and the fixed surface of the second lifter guide at a low cost, according to the present invention, the cam surface of the roller can be provided at a low cost. It is possible to prevent contact with one piece.

  Further, as a means for solving the above-described problems, the method for manufacturing a fuel pump according to the present invention is configured as follows. That is, the fuel pump manufacturing method of the present invention includes a plunger fitted in a cylinder so as to be reciprocally slidable, a lifter connected to the plunger having a roller rolling along a cam surface of the cam, and the cam A first lifter guide having a guide surface for guiding the lifter in a direction perpendicular to the cam surface, and a second lifter guide for fixing and supporting the outer peripheral surface of the first lifter guide, the cam rotating In the manufacturing method of the fuel pump that pressurizes and discharges the fuel by reciprocating the plunger through the lifter, the insertion portion that is inserted along the guide surface in the first lifter guide And a perpendicular calibration jig having a cam contact surface perpendicular to the creeping surface of the insertion portion along the guide surface. And while inserting the insertion part of the said squareness calibration jig along the guide surface in the said 1st lifter guide, after arrange | positioning the cam contact surface of the said squareness calibration jig along the said cam surface An adhesive is filled between the first lifter guide and the second lifter guide.

  According to the method of manufacturing a fuel pump having such a configuration, the insertion portion of the perpendicularity calibration jig is inserted along the guide surface in the first lifter guide, and the cam contact surface of the perpendicularity calibration jig is inserted into the cam surface. The lifter guide direction by the first lifter guide can be accurately orthogonal to the cam surface. Then, in this state, an adhesive is filled between the first lifter guide and the second lifter guide, and if the adhesive is solidified, the orthogonal state is maintained, and the rollers disposed in the first lifter guide It is possible to prevent contact with the cam surface. In addition, since the perpendicularity calibration jig has a simple structure, it can be procured at a low price, and the adhesive filling process can be easily performed. Therefore, according to the present invention, it is possible to prevent one-side contact of the roller with respect to the cam surface at a low cost.

  According to the present invention, it is possible to prevent the rollers from coming into contact with the cam surface at low cost.

[First Embodiment]
Hereinafter, a fuel pump according to a first embodiment of the present invention will be described with reference to the drawings. In the present embodiment, a high-pressure fuel pump used in a direct injection engine will be described as an example. 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 not shown.

  As shown in FIGS. 1 and 2, in the high-pressure fuel pump 100, a cylinder 101 is disposed in a housing 201. Although the detailed structure of the housing 201 is not shown, the position of the housing 201 is fixed with respect to the axial center position of a cam 203 described later.

  A plunger 106 is fitted into the sliding hole 101a of the cylinder 101 so as to be reciprocally slidable in the axial direction. A space defined by the inside of the cylinder 101 and the tip end portion (upper end portion in the figure) of the plunger 106 is a pressurizing chamber 105.

  A first lifter guide 102 and a second lifter guide 103 are disposed on the lower side of the housing 201 (the cam 203 side described later). The first lifter guide 102 is formed of a cylindrical body (cylindrical body in the present embodiment), and guides a lifter 104 described later along a guide surface 102a having an inner diameter surface so as to linearly move. The guide direction of the lifter 104 by the first lifter guide 102 is orthogonal to the outer peripheral surface (cam surface) 203a of the cam 203 described later.

  The second lifter guide 103 fixes and supports the outer peripheral surface 102b of the first lifter guide 102. The second lifter guide 103 includes a through-hole 103a into which the first lifter guide 102 is inserted and fixed, and a cam housing portion 103b. It is fixed on the support part 202a of the head cylinder 202. The outer peripheral surface 102 b of the first lifter guide 102 is fixed to the fixing surface (inner diameter surface) 103 c forming the through hole 103 a of the second lifter guide 103 with an adhesive 109. Note that the second lifter guide 103 does not necessarily have to serve also as a cam housing.

  The lifter 104 is disposed so as to be guided by the guide surface 102 a of the first lifter guide 102, and is connected to a base end portion (lower end portion in the drawing) of the plunger 106 via a retainer and connecting member 107. The retainer and connecting member 107 is formed of an annular member having a central portion that bulges toward the flanger 106, and an inner diameter portion thereof is engaged with an enlarged diameter end portion formed at a proximal end portion of the plunger 106. Moreover, the outer peripheral side of the retainer and connecting member 107 is a spring retainer, and a coil spring 108 is interposed between the spring retainer and the housing 201 in a compressed state.

  The lifter 104 is fixed with a roller support shaft 111 having an axis centered in a direction orthogonal to the moving direction of the lifter 104. A roller 112 is rotatably mounted on the roller spindle 111.

  A cam 203 is disposed below the roller 112 (on the side opposite to the plunger 106). The cam 203 rotates with a cam shaft 204 that is linked to the engine. The outer peripheral surface 203a of the cam 203 (hereinafter also referred to as “cam surface 203a”) is always in contact with the outer peripheral surface 112a of the roller 112 (hereinafter also referred to as “roller surface 112a”) by the biasing force of the coil spring 108. It is said that.

  In addition, since the guide direction of the lifter 104 by the first lifter guide 102 is orthogonal to the cam surface 203a, the roller 112 always has a cam surface 203a even if the cam 203 rotates and the lift amount of the cam 203 varies. Is in line contact with each other, so that it does not touch each other.

  The operation of the high-pressure fuel pump 100 configured as described above will be briefly described.

  When the camshaft 204 rotates as the engine is driven and the cam 203 rotates, the plunger 106 reciprocates in the axial direction via the roller 112, the lifter 104, etc. according to the change in the phase of the cam surface 203a. The high-pressure fuel pump 100 changes the volume in the pressurizing chamber 105 by the operation of the plunger 106 to pressurize and discharge the fuel, or suck the fuel as a premise of pressurization.

  The fuel pressurization and suction processes in the pressurization chamber 105 will be described more specifically. When the lift amount of the plunger 106 by the cam 203 (height from the lowest position of the plunger 106) is the lowest, the roller 112 and the lifter 104 are in the lowest lowered position. At this time, the plunger 106 is also in the lowest lowered position moved in the most retracted direction from the pressurizing chamber 105 in conjunction with the roller 112 and the lifter 104, the volume of the pressurizing chamber 105 is maximized, and the fuel is supplied to the pressurizing chamber. Suction is introduced into 105.

  As the cam 203 further rotates, the lift amount of the plunger 106 by the cam 203 increases, the volume of the pressurizing chamber 105 is compressed, and the pressurizing chamber 105 gradually becomes pressurized. When the lift amount is maximized, the roller 112 and the lifter 104 are at their highest positions. At this time, the plunger 106 reaches the highest position where it protrudes most into the pressurizing chamber 105 in conjunction with the roller 112 and the lifter 104, and the volume of the pressurizing chamber 105 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.

  As the cam 203 further rotates, the lift amount of the plunger 106 by the cam 203 begins to decrease again. As the lift amount of the plunger 106 by the cam 203 decreases, fuel is sucked.

  As described above, in the high-pressure fuel pump 100, the plunger 106 repeatedly reciprocates as the cam 203 rotates. The fuel is pressurized as the plunger 106 is raised, and the fuel is sucked in as the plunger 106 is lowered.

<Method for manufacturing high-pressure fuel pump>
Next, a method for manufacturing the high-pressure fuel pump 100 will be described. Below, the characteristic part of the manufacturing method of the high-pressure fuel pump 100 is mainly demonstrated. The following description will be made assuming that the cylinder 101, the lifter 104, the plunger 106, the retainer and connecting member 107, the coil spring 108, the roller 112, and the like are assembled in advance.

  First, as shown in FIG. 3, the cam shaft 204 is disposed on a bearing 206 formed by the upper portion of the support portion 202 a of the head cylinder 202 and the lower portion of the second lifter guide 103, and the second lifter guide 103 is attached to the bolt 116. Then, it is fixed on the support portion 202a of the head cylinder 202. Here, the fixed surface 103c of the second lifter guide 103 is not orthogonal to the cam surface 203a (a curved surface obtained by extending the cam surface in the axial direction), and is slightly inclined from the original design position. The through hole 103a of the second lifter guide 103 is provided in advance before the second lifter guide 103 is fixed on the head cylinder 202, but the second lifter guide member before the through hole 103a is provided. After fixing on the support portion 202 a of the head cylinder 202, the second lifter guide 103 may be formed by processing the through hole 103 a in the second lifter guide member.

  Next, a squareness calibration jig 300 as shown in FIG. 4 is used. As this squareness calibration jig 300, for example, a well-known chuck device (for example, a chuck device disclosed in Japanese Patent Laid-Open No. 6-106491) with an improved dimensional shape of a slide finger can be used. The squareness calibration jig 300 shown in FIG. 4 has a pair of slide fingers 301 and 301 provided so as to extend in parallel with each other from the chuck device main body 302. The slide fingers 301, 301 are insertion portions that are inserted along the guide surface 102 a in the first lifter guide 102, and are driven by a hydraulic mechanism or a pneumatic mechanism. As shown in the figure, they can approach and separate from each other within a certain range in the width direction. The pair of slide fingers 301, 301 are arranged in the first lifter guide 102, and grip the first lifter guide 102 by sliding in a direction away from each other (direction of arrow P). Also, from this gripping state, the gripping state of the first lifter guide 102 is released by sliding the slide fingers 301 and 301 in the direction approaching each other (the direction opposite to the arrow P).

  As shown in FIG. 5, creeping surfaces 301 a each having a shape along the guide surface 102 a of the first lifter guide 102 are formed on the outer surfaces of the slide fingers 301. Therefore, for example, if the guide surface 102a of the first lifter guide 102 is cylindrical, the creeping surface 301a is a curved surface having the same radius of curvature as the cylindrical shape.

  Further, as shown in FIG. 4, a cam contact surface 301 b is formed at the leading end of each slide finger 301, 301 in the extending direction. The cam contact surfaces 301b and 301b shown in the drawing are flat surfaces formed on the same plane and are orthogonal to the creeping surface 301a.

  Using such a perpendicularity calibration jig 300, first, as shown in FIG. 4, a slide finger 301 which is an insertion portion of the perpendicularity calibration jig 300 is inserted into the first lifter guide 102, and the slide finger 301 is inserted. , 301 are slid in a direction away from each other (in the direction of arrow P), and the first lifter guide 102 is gripped. As a result, the slide fingers 301 and 301 are inserted and fitted along the guide surface 102 a in the first lifter guide 102.

  Next, as shown in FIG. 6, the first lifter guide 102 is inserted into the second lifter guide 103. At this time, it is desirable that the two slide fingers 301, 301 are aligned in the axial direction of the cam shaft 204. Cam contact surfaces 301b and 301b of the slide fingers 301 and 301 are disposed along the cam surface 203a. That is, the cam contact surfaces 301b and 301b of the slide fingers 301 and 301 and the cam surface 203a are arranged in line contact. At this time, since the cam contact surfaces 301b and 301b of the slide finger 301 and the creeping surface 301a are orthogonal to each other, the guide direction of the lifter 104 (not shown in FIG. 6) by the first lifter guide 102 is the cam. It is orthogonal to the surface 203a.

  Next, as shown in FIG. 7, an adhesive 109 is filled between the first lifter guide 102 and the second lifter guide 103. Thus, the first lifter guide 102 is bonded and fixed to the fixing surface 103 c of the second lifter guide 103, and the first lifter guide 102 is supported and fixed by the second lifter guide 103. As a result, the positional relationship in which the guide direction of the lifter 104 by the first lifter guide 102 is orthogonal to the cam surface 203a is maintained.

  After that, as shown in FIG. 8, the slide fingers 301, 301 of the perpendicularity calibration jig 300 are brought close to each other to release the gripped state of the first lifter guide 102, and then removed from the first lifter guide 102. .

  Finally, as shown in FIG. 1, the lifter 104 connected to the plunger 106 is slidably fitted into the guide surface 102 a of the first lifter guide 102 and the roller surface of the roller 112 provided on the lifter 104. 112a is brought into contact with the cam surface 203a.

  At this time, since the positional relationship in which the guide direction of the lifter 104 by the first lifter guide 102 is orthogonal to the cam surface 203a is maintained, the roller can be prevented from coming into contact with the cam surface 203a.

[Second Embodiment]
Next, a high-pressure fuel pump according to a second embodiment of the present invention will be described with reference to FIG. In addition, about the structure similar to what was demonstrated in 1st Embodiment, a same sign is attached | subjected and description is abbreviate | omitted.

  The high-pressure fuel pump 100A in this embodiment is bonded between the first lifter guide 102 and the second lifter guide 103 filled with the adhesive in the high-pressure fuel pump 100 according to the first embodiment described above. An elastic body is loaded instead of the agent. That is, the outer peripheral surface 102 b of the first lifter guide 102 is fixed to the fixing surface 103 c formed on the second lifter guide 103 via an elastic body 114 such as rubber. However, a small amount of adhesive (not shown) is used for this fixing. As the elastic body 114, for example, a cylindrical member having a uniform thickness in the whole in an uncompressed state can be adopted.

  According to the high-pressure fuel pump 100A, the first lifter guide 102 can be tilted with respect to the fixed surface 103c of the second lifter guide 103 by the elastic body 114 being bent in the thickness direction. Therefore, even if the fixed surface 103c of the second lifter guide 103 is not perpendicular to the cam surface 203a and is inclined from the original design position, a load F (for example, about about a predetermined value) is applied to the roller 112 and the lifter 104. 500N) is acting in the direction of the cam 203 (direction perpendicular to the cam surface 203a), the roller 112 is pressed against the cam surface 203a and makes a line contact, and accordingly, the lifter 104 and the first lifter guide 102 Is corrected to the original design position (a position where the guide direction of the lifter 104 by the first lifter guide 102 is orthogonal to the cam surface 203a), and the one-contact of the roller 112 with respect to the cam surface 203a is prevented.

  The present invention can be applied to, for example, a high-pressure fuel pump that supplies fuel to an engine fuel injection valve and the like, and a manufacturing method thereof.

1 is a longitudinal sectional view of a high-pressure fuel pump according to a first embodiment of the present invention. It is AA sectional drawing of FIG. It is sectional drawing which shows the first process in the manufacturing method of the high pressure fuel pump which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the next process of FIG. It is BB sectional drawing of FIG. It is sectional drawing which shows the next process of FIG. It is sectional drawing which shows the next process of FIG. It is sectional drawing which shows the next process of FIG. It is a longitudinal cross-sectional view of the high pressure fuel pump which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

100 High-pressure fuel pump (fuel pump)
100A high pressure fuel pump (fuel pump)
DESCRIPTION OF SYMBOLS 101 Cylinder 102 1st lifter guide 102a Guide surface 102b Outer peripheral surface 103 2nd lifter guide 103c Fixed surface 104 Lifter 106 Plunger 109 Adhesive 112 Roller 114 Elastic body 203 Cam 203a Cam surface 300 Straight angle calibration jig 301 Slide finger (insertion) Part)
301a Creepage 301b Cam contact surface

Claims (3)

A plunger fitted in a cylinder so as to be reciprocally slidable;
A lifter coupled to the plunger having a roller that rolls along the cam surface of the cam;
A lifter guide for guiding the lifter in a direction perpendicular to the cam surface of the cam;
With
A fuel pump that pressurizes and discharges fuel by reciprocating the plunger through the lifter as the cam rotates;
The lifter guide includes a first lifter guide having a guide surface for guiding the lifter in the direction, and a second lifter guide for fixing and supporting the outer peripheral surface of the first lifter guide,
The fuel pump, wherein an outer peripheral surface of the first lifter guide is fixed to a fixing surface of the second lifter guide via an adhesive. A plunger fitted in a cylinder so as to be reciprocally slidable;
A lifter coupled to the plunger having a roller that rolls along the cam surface of the cam;
A lifter guide for guiding the lifter in a direction perpendicular to the cam surface of the cam;
With
A fuel pump that pressurizes and discharges fuel by reciprocating the plunger through the lifter as the cam rotates;
The lifter guide includes a first lifter guide having a guide surface for guiding the lifter in the direction, and a second lifter guide for fixing and supporting the outer peripheral surface of the first lifter guide,
The fuel pump, wherein an outer peripheral surface of the first lifter guide is fixed to a fixed surface of the second lifter guide via an elastic body. A plunger fitted in a cylinder so as to be reciprocally slidable; a roller having a roller that rolls along a cam surface of the cam; and a lifter connected to the plunger; and the lifter in a direction perpendicular to the cam surface of the cam A first lifter guide having a guide surface for guiding the first lifter guide, and a second lifter guide for fixing and supporting the outer peripheral surface of the first lifter guide, and the plunger reciprocates via the lifter as the cam rotates. A method of manufacturing a fuel pump that pressurizes and discharges fuel by moving,
A squareness calibration jig having an insertion portion that is inserted along the guide surface in the first lifter guide, and a cam contact surface that is orthogonal to the creeping surface of the insertion portion along the guide surface. A method of manufacturing a fuel pump using
The insertion portion of the perpendicularity calibration jig is inserted along the guide surface in the first lifter guide, and the cam contact surface of the perpendicularity calibration jig is arranged along the cam surface. Filling an adhesive between the first lifter guide and the second lifter guide;
A method of manufacturing a fuel pump.

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