JP2013147947A - Roller lifter guide device and fuel pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a roller lifter guide device and a fuel pump which can reduce hitting sound and the like at a guide face part of a roller lifter, and also can suppress thermal conduction in the vicinity of the guide face part.SOLUTION: A roller lifter guide device including a lifter housing 24 for reciprocatably guiding a roller lifter 22 which rotatably supports, to a lifter body 26, a roller 25 rollably contacting a drive cam 21 in a guide axial direction orthogonal to a rotational central axis of the drive cam 21. The lifter housing 24 includes: a housing body 41 for housing the roller lifter 22; a guide face part 42 for slidably guiding an outer peripheral part of the roller lifter 22 in the guide axial direction; and a soft material part 43 which is comprised of a material softer than the housing body part 41 and the guide face part 42 and which is interposed between the housing body part 41 and the guide face part 42.

Description

  The present invention relates to a roller lifter guide device and a fuel pump, and more particularly to a roller lifter guide device that guides a lifter with a roller that engages with a drive cam so as to be capable of reciprocating linear movement, and a fuel pump that is suitable for high-pressure pressurization equipped with the device. About.

  When using a roller lifter on the cam follower side, that is, a lifter with a roller, in a motion conversion mechanism that converts rotational motion into reciprocating linear motion using a rotating cam, a roller lifter guide device that guides the roller lifter so that it can reciprocate linearly is used frequently. Has been.

  Conventionally, some fuel pumps that reciprocate the plunger to pressurize the fuel of the internal combustion engine to a high pressure include a motion conversion mechanism that uses a roller lifter guide device at the input portion of the driving force to the plunger.

  As such a roller lifter guide device and a fuel pump, for example, a roller lifter is used in which a roller support portion and a bottom-guided cylindrical portion guided linearly are configured separately from each other so as to be slidable spherically. It is known that the clearance between the bottomed cylindrical portion and the roller support portion is set so that θg ≦ θp, where θg is the inclination due to the guide clearance of the portion and θp is the inclination due to the guide clearance of the plunger. Yes. In this case, the lateral force acting on the plunger is reduced by bringing the roller lifter and the drive cam into line contact (see, for example, Patent Document 1).

  Also, when the roller lifter reciprocates by offsetting the rotation center axis of the drive cam from the center axis of the lifter housing part with respect to the center axis of the lifter housing part that linearly guides the roller lifter, the lifter is lifted from the side wall part of the roller lifter. Also known is one in which the direction of the pressing force (contact pressure) acting on the inner wall surface of the housing portion is always constant (see, for example, Patent Document 2).

JP 2010-196641 A JP 2010-248974 A

  However, in the conventional roller lifter guide device and the fuel pump as described above, it is necessary to prevent seizure or the like and to ensure that the cylindrical surface of the roller is aligned with the lobe portion of the drive cam. There is a limit in terms of cost in strictly managing the perpendicularity between the center axis of the sliding surface of the roller lifter and the rotation center axis of the roller and the drive cam. Therefore, a relatively large guide clearance is set between the roller lifter and the lifter housing portion having a cylindrical guide surface that guides the roller lifter so as to be capable of reciprocating linear movement so that the inclination of the engagement surface of the roller and the drive cam can be absorbed. It was.

  Therefore, in the conventional roller lifter guide device and fuel pump, the roller lifter collides with the guide surface near the top dead center or the bottom dead center where the urging force in the reciprocating direction acting on the roller lifter is reversed. There is a concern that abnormal noise such as a hitting sound is likely to occur, and that the abnormal noise is transmitted to the passenger compartment as noise.

  Further, in the conventional high-pressure pressurizing fuel pump, the lifter housing part for guiding the roller lifter is integrally formed of metal, so that the temperature of the fuel sucked into the high-pressure fuel pump during the operation of the internal combustion engine is reduced. There is a concern that fuel vapor is likely to rise and fuel vapor that adversely affects high-pressure pressurization and fuel injection control of the fuel is generated.

  Accordingly, the present invention provides a roller lifter guide device and a fuel pump that can effectively suppress the occurrence of a hitting sound or the like in the guide surface portion of the roller lifter and can suppress heat conduction in the vicinity of the guide surface portion. is there.

  In the fuel pump according to the present invention, in order to solve the above problems, (1) a roller lifter that rotatably supports a roller in contact with a drive cam on a lifter main body is orthogonal to a rotation center axis of the drive cam. A roller lifter guide device having a lifter housing that is guided so as to be reciprocally movable in the guide axis direction, wherein the lifter housing slides a housing main body portion that houses the roller lifter and an outer peripheral portion of the roller lifter in the guide axis direction. A guide surface portion that is movably guided, and a soft material portion that is made of a material softer than the housing main body portion and the guide surface portion and is interposed between the housing main body portion and the guide surface portion. And

  In this invention, since the soft material portion is interposed between the housing main body portion and the guide surface portion of the lifter housing, the inclination of the engagement surface between the roller and the drive cam is set even if the sliding clearance between the roller lifter and the guide surface portion is set small. In addition, when the tilting direction of the roller lifter relative to the lifter housing is reversed due to the movement of the contact point between the drive cam and the roller lifter, the impact and the sudden increase in contact surface pressure are mitigated by the deformation of the soft material part on the approaching side due to the tilt. The Therefore, it is not necessary to set a large clearance between the roller lifter and the guide surface portion, and noise caused by abnormal noise such as a hitting sound between the roller lifter and the lifter housing near the top dead center or the bottom dead center of the roller lifter is eliminated. Generation is effectively suppressed. In addition, since the lifter housing is not integrally formed of metal and has a soft material portion, the heat conduction between the housing main body portion and the guide surface portion can be effectively suppressed by the thermal resistance of the soft material portion, and from the outside. Can be prevented from being transmitted to the sliding surface of the roller lifter.

  In the roller lifter guide device of the present invention, (2) it is preferable that the soft material of the soft material portion is made of a material having lower thermal conductivity than the housing main body portion and the guide surface portion. With this configuration, heat conduction between the housing main body portion and the guide surface portion can be reliably suppressed by the thermal resistance of the soft material portion.

  In the roller lifter guide device of the present invention, (3) it is desirable that the soft material portion has rubber elasticity. As a result, the guide surface portion can be elastically supported by the housing main body portion, the inclination of the engagement surface of the roller and the drive cam is absorbed by the soft material portion, and the posture of the roller lifter is flexibly adapted to the change of the acting force. The contact pressure on the sliding surface can be maintained within an appropriate range.

  In the roller lifter guide device of the present invention, (4) it is preferable that the soft material of the soft material portion contains a resin. In this case, the soft material portion can be easily formed into a required shape.

  In the roller lifter guide device according to the present invention, (5) the lifter housing passes through at least the guide surface portion and the soft material portion at a specific position in the circumferential direction that is separated from both axial ends of the roller. Preferably, the lifter main body of the roller lifter is provided with a rotation-preventing projection that engages with the notch groove. As a result, the roller lifter can be prevented from rotating by engaging the notch groove of the lifter housing in a concave-convex manner, and the material of the soft material portion is filled between the two while the guide surface portion is supported by the housing body of the lifter housing. It becomes possible to mold the portion, and the soft material portion can be easily loaded between the housing main body and the guide surface portion.

  In the roller lifter guide device of the present invention, (6) the guide surface portion may be made of a material having higher wear resistance than the soft material portion. With this configuration, a stable sliding and guiding state between the roller lifter and the lifter housing can be maintained for a long period of time.

  A fuel pump according to the present invention is (7) a fuel pump including a roller lifter guide device having any one of the above-described configurations, the pump body forming a fuel passage and a fuel pressurizing chamber therein, A plunger that is reciprocally supported by the pump body so as to change the volume of the pressure chamber and that is driven in a direction in which the fuel in the pressurizing chamber is pressurized by the roller lifter, and the plunger through the roller lifter. And an urging mechanism for urging the drive cam side.

  In this fuel pump, the roller lifter guide device can set a guide clearance of about a sliding clearance suitable for preventing seizure, and can effectively suppress the occurrence of hitting sound on the guide surface portion of the roller lifter. It is possible to suppress heat conduction in the vicinity of the guide surface portion. Therefore, seizure of the fuel pump is prevented, and heat from the drive cam side is prevented from being transmitted to the fuel in the fuel pump, thereby preventing the fuel pressurization performance of the fuel pump from being deteriorated due to the generation of fuel vapor. It will be possible.

  According to the present invention, since the soft material portion is interposed between the housing main body portion and the guide surface portion of the lifter housing, even if the inclination direction with respect to the housing main body portion of the roller lifter is reversed, the roller lifter and the guide surface portion are close to each other. An increase in impact and contact surface pressure can be mitigated by the soft material portion. As a result, the clearance between the roller lifter and the guide surface portion can be suppressed to a relatively small clearance value, and the occurrence of abnormal noise such as a hitting sound can be effectively suppressed, and the heat between the housing main body portion and the guide surface portion can be suppressed. It is possible to provide a roller lifter guide device and a fuel pump in which conduction can be effectively suppressed by the soft material portion.

It is sectional drawing which shows schematic structure of the fuel pump provided with the roller lifter guide apparatus which concerns on one Embodiment of this invention. It is II-II sectional drawing of FIG. FIG. 3 is a sectional view taken along line III-III in FIG. 2. It is sectional drawing which shows the principal part structure of the fuel pump provided with the roller lifter guide apparatus which concerns on other embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(One embodiment)
1 to 3 show a roller lifter guide device and a fuel pump according to an embodiment of the present invention.

  The fuel pump of the present embodiment is mounted as a part of a fuel supply system on an internal combustion engine mounted on a vehicle, for example, a multi-cylinder gasoline engine capable of direct in-cylinder injection (hereinafter simply referred to as an engine). This fuel pump is for high-pressure pressurization that supplies high-pressure fuel accumulated and stored in a delivery pipe that distributes high-pressure fuel to a plurality of in-cylinder injectors (fuel injection valves). It is a fuel pump.

  As shown schematically in FIG. 1, the high-pressure fuel pump 10 (fuel pump) of the present embodiment is driven by a drive mechanism 20 having a roller lifter guide device.

  The high-pressure fuel pump 10 is connected to a feed pump provided in a fuel tank (not shown), and fuel pressurized to a relatively low feed pressure is introduced from the feed pump to the high-pressure fuel pump 10. It is like that. The feed pump here is, for example, an electric low-pressure fuel pump that pumps up fuel such as gasoline in a fuel tank.

  As shown in FIGS. 1 to 3, the high-pressure fuel pump 10 of this embodiment includes a pump body 11, a plunger 12 that is mounted on the pump body 11 so as to be capable of reciprocating displacement (reciprocating linear motion) in the axial direction, A fuel pressurizing chamber 13 defined between one end 12a (upper end in FIG. 1) of the plunger 12 and the pump body 11 is provided. The pump body 11 includes a suction passage 11a (only a part of which is shown) for introducing fuel from the feed pump into the fuel pressurizing chamber 13, and the fuel pressurized inside the fuel pressurizing chamber 13 as the delivery pipe. A discharge passage 11b for discharging to the side is formed.

  On the suction side of the fuel pressurizing chamber 13 of the pump body 11, a suction gallery chamber 11k is formed for storing fuel in an upstream portion of the suction passage 11a. Further, the pump body 11 includes a suction valve 14 including a check valve that allows a fuel suction into the fuel pressurization chamber 13 on the downstream side of the suction gallery chamber 11k and that exhibits a backflow prevention function, and a fuel pressurization chamber 13. And a discharge valve 16 including a check valve that allows the fuel to be discharged from the fuel tank and that exhibits a backflow prevention function.

  The suction valve 14 has a valve body 14 capable of opening and closing the suction passage 11a and an annular valve seat 14b, and the valve body 14a until reaching a predetermined suction pressure (a pressure lower than the feed pressure by a predetermined suction valve opening differential pressure). And a valve spring 14c that keeps the valve closed state in contact with the annular valve seat 14b.

  The discharge valve 16 reaches a predetermined discharge pressure (a pressure higher by a predetermined discharge valve opening differential pressure than the fuel pressure in the delivery pipe) with the valve body 16a and the annular valve seat 16b that can open and close the discharge passage 11b. And a valve spring 16c that holds the valve closed state in which the valve body 16a contacts the annular valve seat 16b.

  Therefore, when the plunger 12 is displaced upward in FIG. 1 so as to reduce the volume of the fuel pressurizing chamber 13, the plunger 12 pressurizes the fuel in the fuel pressurizing chamber 13 with the intake valve 14 closed. The fuel can be discharged from the fuel pressurizing chamber 13 while increasing the pressure and opening the discharge valve 16. Further, when the plunger 12 is displaced downward in FIG. 1 so as to increase the volume of the fuel pressurizing chamber 13, the fuel in the fuel pressurizing chamber 13 is depressurized to reduce its pressure. The intake valve 14 is opened in the closed state so that fuel can be sucked into the fuel pressurizing chamber 13.

  The intake valve 14 is provided with an electromagnetic operation mechanism 15. The electromagnetic operating mechanism 15 includes an operating member 15a slidably held in the pump body 11 so as to face the valve body 14a, and the operating member 15a with a biasing force larger than the biasing force of the valve spring 14c of the intake valve 14. A valve opening operating spring 15b that urges toward the valve opening side of the valve body 14a, and an electromagnetic that can displace the operating member 15a toward the valve closing side of the valve body 14a against the urging force of the valve opening operating spring 15b. And a coil portion 15c.

  The electromagnetic operating mechanism 15 can suck the operating member 15a toward the electromagnetic coil unit 15c when the electromagnetic coil unit 15c is energized (ON state) by energization, and the valve element 14a of the intake valve 14 is operated as a valve spring. It can be returned to the valve closing direction by the urging force of 14c. Further, the electromagnetic operating mechanism 15 forces the intake valve 14 against the urging force of the valve spring 14c by the valve opening operating spring 15b when the energization of the electromagnetic coil portion 15c is stopped and becomes a non-excited state (OFF state). The valve can be opened automatically.

  The drive mechanism 20 includes a drive cam 21, a roller lifter 22 that engages with the drive cam 21, and a roller lifter guide device 23 that includes a lifter housing 24 that guides the roller lifter 22 so that it can reciprocate linearly in the guide axis direction. Has been.

  More specifically, the pump body 11 of the high-pressure fuel pump 10 is provided with an oil seal 11 s and has a fitting portion 11 g fitted into the pump fitting hole portion 24 a of the lifter housing 24. A plurality of flange portions 24f each having a mounting hole 24c are integrally provided. The lifter housing 24 is bolted and attached to the head cover H together with the high-pressure fuel pump 10 by a plurality of bolts B inserted into the plurality of mounting holes 24c. As shown in FIG. 1, the high-pressure fuel pump 10 is provided with a flange-shaped attachment ring 11 r that overlaps the flange portion 24 f of the lifter housing 24, and this attachment ring 11 r is made of a material that is harder than the main body portion of the pump body 11. It is constituted by.

  Further, the pump body 11 has a fuel introduction pipe section and a fuel discharge pipe section 11j (not shown), and the fuel sucked through the fuel introduction pipe section is stored in the suction gallery chamber 11k while being sucked into the suction passage. It is sucked into the fuel pressurizing chamber 13 through 11a.

  The plunger 12 is slidably inserted into the pump body 11 at one end 12 a side, and the volume of the fuel pressurizing chamber 13 inside the pump body 11 changes according to the reciprocating displacement of the plunger 12 ( (Increase and decrease), the fuel can be sucked into the fuel pressurizing chamber 13 and the fuel can be discharged from the fuel pressurizing chamber 13.

  The plunger 12 is driven by a drive cam 21 via a roller lifter 22 on the other end 12b side.

  The drive cam 21 is provided in a head cover H (not shown in detail) constituting the pump mounting case, and is driven by rotational power from an engine having the head cover H. The drive cam 21 is integrally mounted on, for example, an exhaust camshaft S (not shown in detail) of the engine, and a plurality of, for example, three cam lobe portions 21a (projecting portions) projecting radially outward at equal angular intervals. Have. Here, the cam lobe portion 21 a of the drive cam 21 has a substantially cylindrical convex shape that makes a line contact with the roller 25 when contacting the roller 25 of the roller lifter 22.

  A spring receiving portion 12c is mounted in the vicinity of the other end portion 12b of the plunger 12, and a compression coil spring 18 (an elastic member) is incorporated in a compressed state between the spring receiving portion 12c and the pump body 11. It is. The spring receiving portion 12 c and the compression coil spring 18 constitute an urging mechanism 19 that urges the plunger 12 toward the drive cam 21 via the roller lifter 22. The plunger 12 is constantly urged by the compression coil spring 18 in the direction of increasing the volume of the fuel pressurizing chamber 13 (downward direction in FIG. 1).

  As shown in FIGS. 2 and 3, the roller lifter 22 includes a cylindrical roller 25 that is rotatably contacted with the drive cam 21, and is rotatably supported by the lifter body 26. And a needle bearing 26b provided between the roller 25 and the support shaft 26a.

  The lifter body 26 is guided inside the lifter housing 24 so as to be slidable in the axial direction, and is urged toward the drive cam 21 by the compression coil spring 18, so that the roller lifter 22 is rotated by the drive cam 21. Accordingly, while rolling the roller 25, the roller 25 can reciprocate in the guide axis direction (vertical direction in FIG. 1) perpendicular to the rotation center axis of the drive cam 21 and passing through the center of the lifter housing 24. .

  Here, the engagement portion between the drive cam 21 and the roller 25 of the roller lifter 22, the sliding portion between the lifter body 26 and the lifter housing 24 of the roller lifter 22, and the other end portion 12 b of the plunger 12 are respectively within the head cover H. It is lubricated by the scattered engine oil.

  On the other hand, the lifter housing 24 is formed in a substantially cylindrical shape for housing the roller lifter 22, and a housing main body 41 in which a flange portion 24 f is integrally formed at one end thereof, and an outer peripheral portion 26 c of the lifter main body 26 of the roller lifter 22 (see FIG. 2) and a soft material portion made of a material softer than the housing body 41 and the guide surface 42 and interposed between the housing body 41 and the guide surface 42. 43.

  The lifter housing 24 has a slit-like or elongated hole-like cutout groove 24g extending in the guide axis direction while penetrating at least the guide surface portion 42 and the soft material portion 43 in the radial direction. The lifter body 26 is prevented from rotating with respect to the lifter housing 24 by engaging with the notch groove 24g. Note that the notch groove 24g of the lifter housing 24 penetrates not only the guide surface portion 42 and the soft material portion 43 but also the cylindrical guide portion 41a of the housing main body portion 41 in FIGS. The cutout groove 24g may be closed on the outer peripheral side of the cylindrical guide portion 41a of the housing body 41. That is, the notch groove 24g may have a bottomed concave shape.

  More specifically, as shown in FIGS. 1 and 2, the cylindrical guide portion 41 a of the housing body 41 has a specific circumferential position (roller 25) that is spaced apart from both axial ends of the roller 25 of the roller lifter 22. At least one slit-like or slot-like notch groove 41g extending in the guide axial direction is formed on at least one side in a direction orthogonal to the axial direction. A rotation-preventing protrusion 26p that protrudes radially outward from the lifter body 26 of the roller lifter 22 is inserted into the notch groove 41g. That is, the roller lifter 22 rotates with respect to the lifter housing 24 at each position where the roller lifter 22 reciprocates in the axial direction by guiding the rotation-preventing projection 26p of the lifter body 26 to the side wall surface portion of the notch groove 41g of the housing body 41. The rotation center axis of the roller 25 and the rotation center axis of the drive cam 21 can be kept substantially parallel.

  The guide surface portion 42 is formed in a substantially cylindrical shape that surrounds the roller lifter 22 inside the housing main body portion 41. The guide surface portion 42 is made of a material having higher wear resistance than the soft material portion 43, for example, metal or wear-resistant resin (or a composite structure thereof), and is formed in a thin, substantially cylindrical shape. At a specific position in the circumferential direction of the guide surface portion 42, at least one notch groove 42g extending in the guide axis direction is formed in substantially the same shape as the notch groove 41g of the housing body 41.

  Here, the inner diameter (inner circumferential surface) of the guide surface portion 42 is large enough to separate the sliding clearance that is large enough to avoid seizure from the outer diameter (outer circumferential surface) of the lifter body 26 of the roller lifter 22 (the guide clearance). The radius is set to a value that is large enough to prevent substantial hitting between the roller lifter 22 and the guide surface portion 42 near the top dead center or the bottom dead center of the roller lifter 22. That is, when the roller 25 gets over the cam lobe portion 21 a (projecting portion) of the drive cam 21 near the top dead center or the bottom dead center of the roller lifter 22 as the drive cam 21 rotates, the roller lifter 22 is moved with respect to the lifter housing 24. The direction in which the biasing force to be tilted (the direction of the moment) is reversed, and the roller lifter 22 reverses the tilting direction with respect to the lifter housing 24. However, the sliding clearance between the lifter body 26 and the guide surface portion 42 of the roller lifter 22 is reversed. Is set so narrow that no sound is generated between the lifter body 26 and the guide surface portion 42 so as to generate noise toward the passenger compartment.

  The soft material portion 43 includes a soft material having lower thermal conductivity than both the housing main body portion 41 and the guide surface portion 42 and having elasticity, for example, rubber or resin having rubber elasticity (viscoelasticity). ing. Specifically, the soft material portion 43 is made of, for example, nitrile rubber (NBR), and is a substantially cylindrical film body that surrounds the guide surface portion 42. Of course, the soft material portion 43 may be formed of an easily molded material such as acrylic rubber (ACM), silicone rubber (VMQ), fluorine rubber (FKM), or other rubber or resin. At a specific position in the circumferential direction of the soft material portion 43, at least one notch groove 43 g extending in the guide axis direction is formed in substantially the same shape as the notch groove 41 g of the housing body 41.

  In the present embodiment, the thickness of the cylindrical wall of the guide surface portion 42 and the cylindrical film thickness of the soft material portion 43 are smaller than the thickness of the cylindrical wall of the housing main body portion 41. Is smaller than the cylindrical film thickness of the soft material portion 43. That is, the guide surface portion 42 is the thinnest.

  A coating with low friction and excellent wear resistance may be formed on the inner peripheral surface of the cylindrical wall of the guide surface portion 42, or the cylindrical film of the soft material portion 43 may be composed of a plurality of different material layers. it can.

  As described above, the high-pressure fuel pump 10 according to the present embodiment includes the roller lifter guide device 23, and the pump body 11 that forms the suction passage 11a, the discharge passage 11b, and the fuel pressurization chamber 13 through which the fuel passes, and the fuel The plunger 12 is supported by the pump body 11 so as to be able to reciprocate linearly so as to change the volume of the pressurizing chamber 13 and is driven in a direction to pressurize the fuel in the fuel pressurizing chamber 13 by the roller lifter 22. And an urging mechanism 19 that urges the drive cam 21 toward the drive cam 21.

  When the drive cam 21 is rotationally driven by the power from the engine, the plunger 12 reciprocates linearly in the axial direction according to the reciprocating displacement of the roller lifter 22 corresponding to the rotation of the drive cam 21. Thereby, the high-pressure fuel pump 10 can suck the fuel into the fuel pressurizing chamber 13, pressurize it, and discharge it.

  The high-pressure fuel pump 10 controls the period during which the intake valve 14 is forcibly opened by energizing the electromagnetic coil portion 15 c of the electromagnetic operation mechanism 15, so that the fuel in the fuel pressurizing chamber 13 by the plunger 12 is supplied. The pressurization period can be variably controlled, and the amount of fuel discharged can be controlled.

  The pump body 11 of the high-pressure fuel pump 10 is composed of a plurality of cylindrical or annular segments (no reference numerals) that are adjacent in the axial direction and are fluid-tightly fitted to each other via a seal ring such as an O-ring. It may be. A seal mechanism 31 interposed between the pump body 11 and the plunger 12 is provided on the lower end side in FIG. 1 of the pump body 11 exposed in the head cover H. The seal mechanism 31 includes an annular folded portion 32 folded back to accommodate the upper end portion of the compression coil spring 18 in FIG. 1, an oil seal portion 33 that engages with the lower end portion of the plunger 12 in FIG. And a garter spring 34 that applies a required tightening force to the seal portion 33.

  Next, the operation will be described.

  In the roller lifter guide device and the fuel pump 10 of the present embodiment configured as described above, since the soft material portion 43 is interposed between the housing main body portion 41 and the guide surface portion 42 of the lifter housing 24, the roller lifter 22. And the sliding clearance between the guide surface portions 42 can be set small.

  That is, when the axis of the roller 25 is inclined following the drive cam 21 and the roller lifter 22 is inclined with respect to the lifter housing 24, the soft material portion 43 is partially deformed on the increase side of the contact surface pressure due to the inclination. The increase in the contact surface pressure is sufficiently absorbed, and the uneven contact pressure on the sliding surfaces of the roller lifter 22 and the lifter housing 24 is sufficiently relieved. Therefore, it is not necessary to set the clearance between the roller lifter 22 and the guide surface portion 42 so as to exceed a clearance value suitable for preventing seizure.

  In addition, since the clearance between the roller lifter 22 and the guide surface portion 42 is kept small, the lifter body of the roller lifter 22 is near the top dead center or the bottom dead center of the roller lifter 22 where the inclination direction of the roller lifter 22 with respect to the lifter housing 24 is reversed. The speed at which 26 collides with the guide surface portion 42 does not increase, and the occurrence of abnormal noise such as a hitting sound between the roller lifter 22 and the guide surface portion 42 is effectively suppressed. Further, since the soft material portion 43 can function as a buffer material when an impact is applied to the hard guide surface portion 42 or the lifter housing 24, the generation of abnormal noise such as hitting sound is also effective from this point of view. In addition to being suppressed, it is also possible to suppress external vibration from being transmitted to the sliding surface of the roller lifter 22.

  In the present embodiment, the lifter housing 24 is not integrally formed of metal and has the soft material portion 43, so that the heat conduction between the housing main body portion 41 and the guide surface portion 42 is performed by the heat of the soft material portion 43. It can be effectively suppressed by resistance. In particular, since the soft material of the soft material portion 43 is made of a material having lower thermal conductivity than the housing main body portion 41 and the guide surface portion 42, heat conduction between the housing main body portion 41 and the guide surface portion 42 can be reliably suppressed. Therefore, an increase in the temperature of the fuel in the high-pressure fuel pump 10 due to heat inside the engine is suppressed.

  Furthermore, in this embodiment, since the soft material part 43 has rubber elasticity, the guide surface part 42 can be elastically supported by the housing main body part 41. Therefore, the soft material portion 43 absorbs the inclination of the engagement surface between the roller 25 and the drive cam 21, and the posture of the roller lifter 22 is flexibly changed with respect to the change of the force acting on the roller lifter 22. It becomes possible to maintain the contact pressure of the sliding surface between the lifter housings 24 within an appropriate range. Moreover, in this embodiment, when the soft raw material of the soft material part 43 contains resin, the soft material part 43 can be easily shape | molded by a shaping | molding die with a required shape.

  In addition, the lifter housing 24 has a notch groove 24g at a specific position in the circumferential direction, and the lifter body 26 of the roller lifter 22 is provided with a rotation-preventing protrusion 26p that engages with the notch groove 24g. ing. Therefore, the roller lifter 22 can be engaged with the notch groove 24g of the lifter housing 24 so as to be prevented from rotating and the rotation of the roller lifter 22 can be prevented, and the material of the soft material portion 43 can be used with the guide surface portion 42 supported by the housing main body portion 41 of the lifter housing 24. It is possible to form the soft material portion 43 by filling in between, and the soft material portion 43 can be easily loaded between the housing main body portion 41 and the guide surface portion 42. In addition, the notch groove 24g can enhance functions such as shock absorption when the roller lifter 22 is tilted with respect to the lifter housing 24 and a reduction in contact surface pressure.

  In this embodiment, since the guide surface portion 42 is made of a material having higher wear resistance than the soft material portion 43, a stable sliding and guiding state between the roller lifter 22 and the lifter housing 24 can be maintained for a long period of time.

  On the other hand, the high-pressure fuel pump 10 of this embodiment includes a pump body 11, a plunger 12, and an urging mechanism 19 that urges the plunger 12 toward the drive cam 21 via a roller lifter 22. Therefore, in this high-pressure fuel pump 10, the roller lifter guide device 23 can effectively suppress the occurrence of sound and the like between the roller lifter 22 and the guide surface portion 42, and the heat conduction in the vicinity of the guide surface portion 42 can be suppressed. It becomes possible to suppress. As a result, heat from parts in the cylinder head covered with the head cover H, engine oil, etc. is prevented from being transmitted to the fuel in the high-pressure fuel pump 10, and fuel pressurization performance by the high-pressure fuel pump 10 due to the generation of fuel vapor. Is prevented from decreasing.

  Thus, according to this embodiment, since the soft material part 43 is interposed between the housing main body part 41 and the guide surface part 42 of the lifter housing 24, the contact position of the drive cam 21 and the roller lifter 22 changes. Even if the roller lifter 22 is inclined with respect to the housing main body 41 of the lifter housing 24, the soft material portion 43 generates an impact or contact surface pressure on the side closer to the lifter main body 26 of the roller lifter 22 and the guide surface portion 42 of the lifter housing 24. The increase can be absorbed. As a result, the sliding clearance between the roller lifter 22 and the guide surface portion 42 can be set to an appropriate clearance, so that the generation of abnormal noise such as hitting can be effectively suppressed, and the housing main body portion 41 and the guide surface portion The heat conduction between 42 can be effectively suppressed by the soft material portion 43.

(Other embodiments)
FIG. 4 shows a main part configuration of a high-pressure fuel pump provided with a roller lifter guide device according to another embodiment of the present invention, and corresponds to FIG. 2 which is a cross-sectional view of the main part of the above-described embodiment.

  Since the present embodiment has an overall configuration substantially similar to that of the above-described embodiment, the components common to the embodiment are denoted by the reference numerals shown in FIGS. 1 to 3 in FIG. Only the differences will be described.

  In the above-described embodiment, the number of notch grooves 24g formed in the lifter housing 24 is one. However, in this embodiment, the number of notch grooves 24g formed in the lifter housing 24 is plural. It has become. That is, the notch grooves 24g of the lifter housing 24 are formed on both sides in the direction orthogonal to the axis of the roller 25 as shown in FIG.

  Here, the pair of notch grooves 24g of the lifter housing 24 are shown in the same shape, but may be different.

  Further, the groove width (circumferential width) of the notch grooves 42g and 43g of the guide surface portion 42 and the soft material portion 43 is made wider than the groove width of the notch groove 41g of the housing main body portion 41, so that the lifter housing of the roller lifter 22 is provided. Functions such as shock absorption at the time of inclination with respect to 24 and relaxation of increase in contact surface pressure may be further improved.

  Also in the present embodiment, as in the case of one embodiment, the sliding clearance between the roller lifter 22 and the guide surface portion 42 is set to an appropriate clearance to effectively suppress the generation of abnormal noise such as a hitting sound. In addition, the heat conduction between the housing main body 41 and the guide surface portion 42 can be effectively suppressed by the soft material portion 43.

  In each of the above-described embodiments, the soft member 43 has a substantially cylindrical shape having the notch groove 24g. However, the soft member 43 is separated from at least one of the axial direction and the circumferential direction of the lifter housing 24. It is also possible to adjust the formability, strength, or elastic characteristics by mixing a plurality of types of soft members.

  In each of the above-described embodiments, the lower end portion of the pump body 11 is fitted and fixed to the upper end side of the lifter housing 24, and a plurality of mounting flange portions 24f are provided. A plurality of mounting flange portions are integrally provided at the lower end portion of 11, and the outer peripheral surface portion on the upper end side of the lifter housing is fitted into the inner peripheral surface of the lower end portion of the pump body 11 or fixed by another fixing method. It can also be configured.

  Further, when the pump body 11 is constituted by a plurality of cylindrical segments and a lid member that closes the end thereof, the lower end side of the pump body 11 of the high-pressure fuel pump 10 is closed and the plunger 12 can slide. It is also conceivable that an annular or tubular cylinder member (including a member whose one end is closed) and a seal holding member are assembled in advance on the lifter housing 24 side.

  Of course, the component configuration and passage shape of the pump body 11 of the high-pressure fuel pump 10, the shape of the intake valve 14, the discharge valve 16, the relief valve (not shown), the mounting structure, etc. are limited to those exemplified in the above-described embodiment. It goes without saying that it is not done.

  The roller lifter guide device of the present invention is also suitable for a plunger-type pump other than the high-pressure fuel pump, and can also be applied to other devices having an input member driven by a reciprocating linear motion of the roller lifter.

  As described above, the present invention has a soft material portion interposed between the housing main body portion and the guide surface portion of the lifter housing, so that the clearance between the roller lifter and the guide surface portion is suppressed to a relatively small clearance value, A roller lifter guide device and a fuel pump that can effectively suppress the occurrence of abnormal noise such as a hitting sound, and that can effectively suppress heat conduction between the housing main body portion and the guide surface portion by the soft material portion. Can be provided. The present invention as described above is useful for a roller lifter guide device that guides a lifter with a roller that engages with a drive cam so as to be capable of reciprocating linear movement, and a high-pressure pressurizing fuel pump that includes the device.

10 High-pressure fuel pump (fuel pump)
DESCRIPTION OF SYMBOLS 11 Pump body 11g Insertion part 12 Plunger 13 Fuel pressurization chamber 14 Suction valve 15 Electromagnetic operation mechanism 16 Discharge valve 18 Compression coil spring (elastic member)
19 Biasing mechanism 20 Drive mechanism 21 Drive cam 21a Cam lobe part (protrusion part)
22 Roller Lifter 23 Roller Lifter Guide Device 24 Lifter Housing 24g Notch Groove 25 Roller 26 Lifter Main Body 26c Outer Perimeter 26p Non-rotating Protrusion 31 Seal Mechanism 41 Housing Body 41g, 42g, 43g Notch Groove 42 Guide Surface Part 43 Soft Material Part B Bolt H Head cover S Exhaust camshaft

Claims (7)

A roller lifter guide provided with a lifter housing that guides a roller lifter rotatably supported by a lifter main body on a lifter body so as to be able to reciprocate in a guide axis direction perpendicular to the rotation center axis of the drive cam. A device,
The lifter housing is composed of a housing main body portion that houses the roller lifter, a guide surface portion that guides the outer peripheral portion of the roller lifter so as to be slidable in the guide axis direction, and a material softer than the housing main body portion and the guide surface portion. A roller lifter guide device comprising: a soft material portion interposed between the housing main body portion and the guide surface portion.   The roller lifter guide device according to claim 1, wherein the soft material of the soft material portion is made of a material having a lower thermal conductivity than the housing main body portion and the guide surface portion.   The roller lifter guide device according to claim 1, wherein the soft material portion has rubber elasticity.   The roller lifter guide device according to any one of claims 1 to 3, wherein the soft material of the soft material portion contains a resin.   The lifter housing has a notch groove extending in the guide axis direction through at least the guide surface portion and the soft material portion at a specific position in the circumferential direction separated from both axial ends of the roller, The said lifter main body of a roller lifter is provided with the protrusion for rotation prevention which carries out an uneven | corrugated engagement with respect to the said notch groove, The claim of any one of Claim 1 thru | or 4 characterized by the above-mentioned. Roller lifter guide device.   The roller lifter guide device according to any one of claims 1 to 5, wherein the guide surface portion is made of a material having higher wear resistance than the soft material portion. A fuel pump comprising the roller lifter guide device according to any one of claims 1 to 6,
A pump body that forms a fuel passage and a fuel pressurizing chamber therein;
A plunger that is supported by the pump body so as to be able to reciprocate linearly so as to change the volume of the pressurizing chamber, and that is driven in a direction to pressurize the fuel in the pressurizing chamber by the roller lifter;
A fuel pump, comprising: a biasing mechanism that biases the plunger toward the drive cam via the roller lifter.

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