JP2007177704A - High pressure pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high pressure pump capable of surely inhibiting seizure caused by heat generation accompanying slide of a plunger. <P>SOLUTION: The plunge 32 is reciprocatably fitted in a slide hole 31 of a cylinder body 29 between a pressurizing chamber 35 and a drive cam 22. Fuel 10 is sucked into the pressurizing chamber 35 by moving the plunger to the drive cam 22 side by the drive cam 22 and a coil spring 41, and the fuel 10 in the pressurizing chamber 35 is pressurized by moving the plunger 32 to the pressurizing chamber 35 side. Moreover, a gap between the plunger 32 and a wall surface 46 of the slide hole 31 is used as a flow passage 47 of the fuel 10 flowing out of the pressurizing chamber 35. A fuel retention groove 55 temporarily retaining the fuel 10 flowing in the flow passage 47 is provided near a section which the plunger contact with high contact pressure with accompanying slide of the plunger 32 of the wall surface 46 of the slide hole 31 in such a high pressure fuel pump 17. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention reciprocates the plunger in the sliding hole of the cylinder body to change the volume of the pressurizing chamber, thereby pressurizing the suction stroke for sucking the liquid into the pressurizing chamber and the liquid in the pressurizing chamber. The present invention relates to a high-pressure pump that performs a pressurizing stroke.

For example, a plunger-type high-pressure pump is known as a high-pressure fuel pump that is incorporated in an in-vehicle engine or the like and supplies fuel to a fuel injection valve or the like (for example, see Patent Document 1).
As shown in FIG. 20, the high-pressure pump includes a cylinder body 71, a plunger 73 fitted into the sliding hole 72 of the cylinder body 71 so as to be slidable back and forth, and one end side of the sliding hole 72 (in FIG. A pressurizing chamber 74 provided on the upper side, and a lifter 75 and a drive cam 76 provided on the other end side (lower side in FIG. 20) of the sliding hole 72 are provided. The lifter 75 is in contact with the plunger 73 at the inner bottom thereof, and is guided by the lifter guide 77 so as to be slidable back and forth. The lifter 75 is urged toward the drive cam 76 by a spring 78. The high pressure pump 85 is configured to reciprocate and slide the plunger 73 in the sliding hole 72 by rotating the drive cam 76, and to change the volume of the pressurizing chamber 74 to suck and pressurize the fuel 79. .

  That is, when the drive cam 76 further rotates from the state where the plunger 73 is located at the top dead center, the push-up force of the drive cam 76 is weakened, the lifter 75 biased by the spring 78 is lowered, and the plunger 73 is lowered. Move to 76 side. Along with this, the volume of the pressurizing chamber 74 gradually increases, and the fuel 79 is sucked into the pressurizing chamber 74 (intake stroke). On the other hand, when the drive cam 76 further rotates from the state where the plunger 73 is located at the bottom dead center, the pushing force of the drive cam 76 is increased, the lifter 75 is raised against the spring 78, and the plunger 73 is added. Move to the pressure chamber 74 side. Along with this, the volume of the pressurizing chamber 74 gradually decreases, and the fuel 79 in the pressurizing chamber 74 is pressurized (pressurization stroke). Then, by closing the electromagnetic spill valve 81 during the pressurization stroke, the overflow of the fuel 79 from the pressurization chamber 74 is stopped and the fuel 79 is increased in pressure. When the pressure of the fuel 79 exceeds the specified value, the check valve 82 is opened and the fuel 79 is discharged to the fuel injection valve side.

As shown in FIG. 21, a slight gap between the plunger 73 and the wall surface 83 of the sliding hole 72 serves as a flow passage 84 for the fuel 79 from the pressurizing chamber 74. Lubrication and cooling are performed by the flowing fuel 79 so as to suppress seizure due to heat generated as the plunger 73 reciprocates.
JP 2001-41129 A

  By the way, in the high pressure pump 85, the lifter 75 is pushed up by the drive cam 76, the plunger 73 is moved to the pressurizing chamber 74 side, and the drive cam 76 is pushed up in the pressurization stroke in which the fuel 79 is pressurized. The force Fu is generated as a force toward the pressurizing chamber 74. In addition, the reaction force Fr when the fuel 79 is boosted is generated as a force directed to the drive cam 76.

  The drive cam 76 contacts the center C of the lifter 75 at the base circle portion 76A. The contact point Pa of the drive cam 76 with the lifter 75 is displaced with the rotation of the drive cam 76 and deviates from the center C of the lifter 75. Due to this, as shown in FIG. 21, the lifter 75 tilts within a range allowed by the clearance with the lifter guide 77. The plunger 73 tilts in the sliding hole 72 due to the moment, and a force (lateral force Fs) is applied from the plunger 73 to the pressurizing chamber side end Ep and the driving cam side end Ed of the sliding hole 72. To do.

  In particular, in recent years, there is a tendency to increase the fuel discharge amount or pressure of the high-pressure pump 85 in order to improve engine performance. In this case, the lateral force Fs may be increased. That is, when increasing the fuel discharge amount, it is effective to bring the closing timing of the electromagnetic spill valve 81 closer to the bottom dead center of the plunger 73. This is because the overflow of the fuel is stopped when the volume of the pressurizing chamber 74 reaches the maximum or close to the volume. However, on the other hand, the reaction force Fr at the time of boosting the fuel 79 increases, and the lateral force Fs increases accordingly. As a result, the amount of heat generated by the sliding of the plunger 73 increases at the driving cam side end Ed and the pressure chamber side end Ep of the sliding hole 72, and the fuel 79 flowing through the flow passage 84 ensures the seizure. May not be able to be suppressed.

  In Patent Document 1, the clearance between the plunger 73 and the wall surface 83 of the sliding hole 72 is increased on the pressurizing chamber 74 side as compared with the drive cam 76 side, so that the plunger 73 is in the pressurizing chamber side end portion Ep. It is made to contact the drive cam side edge part Ed earlier. However, no special measures are taken for the drive cam side end portion Ed. For this reason, the above-described problems may still occur.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a high-pressure pump that can reliably suppress seizure due to heat generated by sliding of a plunger.

In the following, means for achieving the above object and its effects are described.
According to the first aspect of the present invention, the plunger is slidably fitted into the sliding hole of the cylinder body between the pressurizing chamber and the drive cam, and the plunger is moved toward the drive cam by the drive cam. Liquid is sucked into the pressurizing chamber, and the plunger is moved to the pressurizing chamber side by the drive cam to pressurize the liquid in the pressurizing chamber, and further, the plunger and the wall surface of the sliding hole In the high pressure pump in which the gap is a flow passage for the liquid flowing out of the pressurizing chamber, the flow passage is provided in the vicinity of the wall where the plunger comes into contact with a high surface pressure as it slides. A liquid holding recess for temporarily holding the flowing liquid is provided.

  According to the above configuration, in the high-pressure pump, the plunger is driven by the drive cam and reciprocally slides within the sliding hole of the cylinder body. When the plunger is moved to the drive cam side (non-pressurizing chamber side), the volume of the pressurizing chamber increases, and the liquid is sucked into the inside thereof. When the plunger is moved to the pressurizing chamber side, the volume of the pressurizing chamber decreases and the liquid inside the pressurizing chamber is pressurized. Part of the pressurized liquid flows out into the flow path between the plunger and the wall surface of the sliding hole. The liquid flowing through the flow passage lubricates and cools the plunger and the wall surface.

  By the way, in the high pressure pump, when the plunger is moved to the pressurizing chamber side by the drive cam and the liquid in the pressurizing chamber is pressurized, the plunger is inclined with respect to the sliding hole. A force (lateral force) is applied from the inclined plunger to the wall surface of the sliding hole. Due to the lateral force, the plunger generates heat more than the other portions in the portion where it slides in contact with the wall surface at a high surface pressure.

  In this regard, in the invention according to claim 1, wherein the liquid retaining recess is provided on the wall surface of the sliding hole, a part of the liquid in the pressurizing chamber that has flowed out to the flow passage is in the process of flowing through the flow passage. Temporarily held. The liquid holding recess is provided in the vicinity of the location where the plunger comes into contact with high surface pressure as it slides, and the liquid volume is higher in the flow path where the liquid holding recess is provided than in other locations. large. Therefore, lubrication / cooling of a portion having a high surface pressure is enhanced by the liquid having a large volume in the liquid holding recess. As a result, it is possible to reliably suppress seizure due to heat generated by the sliding of the plunger, as compared with the case without such a liquid holding recess.

According to a second aspect of the present invention, in the first aspect of the present invention, the liquid holding recess is provided in the vicinity of the driving cam side end of the wall surface of the sliding hole.
Here, when the plunger is moved to the pressurizing chamber side by the drive cam and the liquid in the pressurizing chamber is pressurized, the plunger has both end portions (in the length direction of the sliding hole in the cylinder body) The driving cam side end and the pressurizing chamber side end) are in contact with a high surface pressure. At the drive cam side end and the pressurizing chamber side end of the sliding hole, the amount of heat generated by sliding of the plunger is greater than at other locations, and a large amount of liquid is required to suppress seizure. On the other hand, in the high-pressure pump, the volume of liquid in the pressurizing chamber is large, and heat dissipation is promoted at the pressurizing chamber end near the pressurizing chamber, while at the driving cam side end away from the pressurizing chamber. The liquid volume may not be sufficient.

  In this respect, the liquid holding recess is provided in the vicinity of the drive cam side end on the wall surface of the sliding hole. In the invention according to claim 2, the liquid flows into the liquid holding recess in the process of flowing through the flow path. Temporarily retained. In the flow passage, in the vicinity of the end portion on the drive cam side where the liquid holding recess is provided, the volume of the liquid is larger than in other portions. Therefore, even if the plunger comes into contact with the driving cam side end on the wall surface of the sliding hole with a high surface pressure, the contact portion and many of the liquid holding recesses provided corresponding to the driving cam side end are provided. The heat exchange with the liquid is efficiently performed.

  According to a third aspect of the present invention, in the second aspect of the present invention, the liquid holding recess is formed in a circumferential direction of the wall surface of the sliding hole, and the plunger is pressurized by the plunger. When it is divided into a contact side region that contacts the wall surface of the sliding hole when moving to the chamber side and a non-contact side region that does not contact, the contact side region is larger than the non-contact side region Suppose that it has a cross-sectional area.

  In the high pressure pump, when the plunger is moved to the pressurizing chamber side by the drive cam and the liquid in the pressurizing chamber is pressurized, the plunger is inclined with respect to the sliding hole and comes into contact with the end portion on the drive cam side. At this time, the plunger does not contact with a uniform strength over the entire circumference of the wall surface of the sliding hole but generates a large amount of heat by strongly contacting a specific portion.

  In this regard, in the invention described in claim 3, the cross-sectional area of the liquid holding recess is not uniform in the circumferential direction, and the cross-sectional area of the contact side region is set larger than the cross-sectional area of the non-contact side region. The contact-side region is a region on the side that comes into contact with the wall surface of the sliding hole when the plunger moves to the pressurizing chamber side, and corresponds to a location where a large amount of heat is generated due to the sliding of the plunger. The non-contact side region is a region on the side that does not contact the wall surface when the plunger moves to the pressurizing chamber side, and corresponds to a place where the amount of heat generated by sliding of the plunger is smaller than that of the contact side region. . The amount of liquid held in the liquid holding recess is large in the contact side region and small in the non-contact side region due to the above setting regarding the relationship between the region of the liquid holding recess and the size of the cross-sectional area. In the liquid holding recess, the volume of the liquid contacting the plunger and the wall surface of the sliding hole is large in the contact side region and small in the non-contact side region.

  Accordingly, lubrication / cooling can be performed without excess or deficiency by using the liquid in the contact side region having a large cross-sectional area for the portion with a large calorific value and the liquid for the non-contact side region having a small cross-sectional area for the portion having a small calorific value.

  In order to make the cross-sectional area of the contact-side region larger than the cross-sectional area of the non-contact-side region, the liquid-holding concave portion is made larger than the non-contact-side region. You may form deeply in a contact side area | region. Further, according to the invention described in claim 5, the liquid holding recess may be formed wider in the contact side region than in the non-contact side region. Further, according to the invention as set forth in claim 6, the contact side region is provided in a state of being arranged in the length direction of the sliding hole and is configured by a groove portion having a larger number than the non-contact side region. Good.

  According to a seventh aspect of the present invention, in the invention according to the second aspect, the liquid holding recess has a pressurizing chamber side end portion in addition to the vicinity of the driving cam side end portion of the wall surface of the sliding hole. It is assumed that it is provided in the vicinity of.

  Here, when the plunger is moved to the pressurizing chamber side by the drive cam and the liquid in the pressurizing chamber is pressurized, the plunger has the length direction of the sliding hole in the cylinder body as described above. In addition to the driving cam side end portion, the pressurizing chamber side end portion is also brought into contact with a high surface pressure. Even at the pressurizing chamber side end portion of the sliding hole, although not as much as the driving cam side end portion, the amount of heat generated by the sliding of the plunger is greater than at other locations. In high-pressure pumps, the volume of liquid in the pressurizing chamber is large, and although heat dissipation is promoted at the end of the pressurizing chamber near the pressurizing chamber, in order to suppress seizure, Requires a large amount of liquid.

  In this respect, in the invention according to claim 7, the liquid holding recess is provided in the vicinity of the end portion on the side of the pressurizing chamber in addition to the vicinity of the end portion on the side of the driving cam on the wall surface of the sliding hole. In the process of flowing through the flow passage, both liquid holding recesses are temporarily held. In the flow passage, the volume of the liquid is larger in the vicinity of the end portion on the drive cam side and the end portion on the pressurization chamber side where the liquid holding recess is provided, respectively, than in other portions. Therefore, even if the plunger contacts the pressurizing chamber side end and the drive cam side end on the wall surface of the sliding hole with a high surface pressure, the contact portion and the liquid holding recess provided in the vicinity of the end Heat exchange with many liquids is efficiently performed.

  According to an eighth aspect of the present invention, in the seventh aspect of the invention, the liquid holding recess located near the driving cam side end is more than the liquid holding recess located near the pressurizing chamber side end. Is also assumed to have a large cross-sectional area.

  As described above, in the high pressure pump, since the volume of the liquid in the pressurizing chamber is large at the end near the pressurizing chamber, the heat radiation is promoted. On the other hand, the volume of the liquid is small at the end portion on the drive cam side away from the pressurizing chamber. Therefore, more liquid is required at the driving cam side end than at the pressurizing chamber side end for lubrication and cooling.

  In this regard, in the invention described in claim 8, the cross-sectional area of the liquid holding recess positioned near the drive cam side end is larger than the cross-sectional area of the liquid holding recess positioned near the pressurizing chamber side end. Is set. With this setting, a larger amount of liquid flowing in the flow passage is held in the liquid holding recess on the drive cam side than on the pressure holding chamber side. The volume of the liquid that comes into contact with the plunger at both ends of the sliding hole is larger at the driving cam side end than at the pressurizing chamber side end.

  Therefore, the end of the sliding chamber where the heat release is promoted by the liquid in the pressurizing chamber is caused by the liquid in the liquid holding recess having a small cross-sectional area, and the effect of promoting the heat dissipation is small. The ends can be lubricated and cooled by the liquid in the liquid holding recesses having a large cross-sectional area without excess or deficiency.

  In order to make the cross-sectional area of the liquid holding recess different between the pressurizing chamber side and the drive cam side as described above, the liquid located in the vicinity of the end portion on the drive cam side as described in claim 9. The holding recess may be formed deeper than the liquid holding recess positioned in the vicinity of the pressurizing chamber side end. According to the tenth aspect of the present invention, the liquid holding recess positioned near the driving cam side end may be formed wider than the liquid holding recess positioned near the pressurizing chamber end. Good. Further, according to the invention of claim 11, the liquid holding recesses located in the vicinity of the drive cam side end are provided in a state of being arranged in the length direction of the sliding hole, and the pressurization chamber side end You may comprise by a groove part with many numbers rather than the liquid holding | maintenance recessed part located in the vicinity of a part.

(First embodiment)
Hereinafter, a first embodiment in which the high-pressure pump of the present invention is embodied in a high-pressure fuel pump provided in an engine fuel supply system will be described with reference to FIGS.

  As shown in FIG. 1, a delivery pipe 12 that is a common high-pressure fuel pipe is connected to a plurality of fuel injection valves 11 provided for each cylinder of the engine, and the fuel in the delivery pipe 12 is used as each fuel. The fuel is distributed and supplied to the injection valve 11. Each fuel injection valve 11 is controlled to open and close, thereby directly injecting and supplying high-pressure fuel to the combustion chamber of the corresponding cylinder. The injected fuel mixes with the air in the combustion chamber and becomes an air-fuel mixture.

  A fuel supply device 13 for supplying high-pressure fuel to the delivery pipe 12 includes a low-pressure fuel pump 15 fixed in the fuel tank 14 and an engine, and is connected to the low-pressure fuel pump 15 via the low-pressure fuel passage 16. And a high-pressure fuel pump 17 connected thereto.

  The low-pressure fuel pump 15 is driven by an electric motor (not shown) that uses a battery as a power source, sucks up the fuel 10 from the fuel tank 14, and discharges the fuel 10 into the low-pressure fuel passage 16. 1 is a pressure regulator for making the fuel pressure (feed pressure) in the low pressure fuel passage 16 constant, and 19 is a pulse regulator for reducing the pulsation of the fuel 10 in the low pressure fuel passage 16. It is a session damper.

  As shown in FIGS. 2 and 3, the high-pressure fuel pump 17 is driven by the camshaft 21 of the engine, and the fuel 10 sent from the low-pressure fuel pump 15 through the low-pressure fuel passage 16 is a substantially cylindrical plunger. This is a type of pump that sucks and pressurizes by 32 reciprocating slides.

  More specifically, a drive cam 22 for driving the high-pressure fuel pump 17 is provided on the camshaft 21 that rotates clockwise as indicated by an arrow. The drive cam 22 includes a base circular portion 23 having a disk shape and a plurality of cam noses 24 protruding from the base circular portion 23.

  The high-pressure fuel pump 17 includes a bracket 26 having a hole 25, and the bracket 26 is fixed to the cylinder head of the engine. The hole 25 is located in the vicinity of the drive cam 22, and a substantially cylindrical lifter guide 27 having both ends opened is inserted into the hole 25. The other end of the cylinder body 29 (the lower end in FIGS. 2 and 3) is attached to the open end of one of the lifter guides 27 (upper side in FIGS. 2 and 3) via a substantially cylindrical seat 28. ing. The cylinder body 29 is formed with a sliding hole 31 opened at both ends. The center line L of the sliding hole 31 is located on the same plane (plane P) as the rotation center R of the camshaft 21. The plunger 32 is fitted into the sliding hole 31 so as to be slidable back and forth.

  The cylinder body 29 is covered with a cover 33 from one end side (the upper side in FIG. 2). The cover 33 is fastened to the bracket 26 with bolts 34. By this fastening, the cylinder body 29 is held between the cover 33 and the bracket 26.

  A pressurizing chamber 35 is formed in the cylinder body 29 in communication with the sliding hole 31. The pressurizing chamber 35 is connected to the low pressure fuel passage 16, and the fuel 10 discharged from the low pressure fuel pump 15 can flow into the pressurizing chamber 35 through the low pressure fuel passage 16. The pressurizing chamber 35 is connected to the delivery pipe 12 through a high-pressure fuel passage 36 (see FIG. 1). In the cylinder body 29, a check valve 37 that opens only when the pressure of the fuel 10 in the pressurizing chamber 35 exceeds a specified value is provided at a connection point between the pressurizing chamber 35 and the high-pressure fuel passage 36. Yes.

  In order to change the volume of the pressurizing chamber 35 by transmitting the rotation of the drive cam 22 to the plunger 32 and reciprocatingly sliding in the sliding hole 31, the following structure is adopted. In the lifter guide 27, a lifter 38 having a bottomed cylindrical shape is inserted and supported so as to be slidable back and forth in a direction along the center line L (length direction of the sliding hole 31). On the other hand, a part of the plunger 32 (lower part in FIGS. 2 and 3) protrudes from the cylinder body 29 and enters the lifter guide 27. A retainer 39 is mounted on the outer periphery of the end of the plunger 32 on the drive cam 22 side, and a coil spring 41 is interposed between the retainer 39 and the seat 28 in a compressed state. With this coil spring 41, the plunger 32 is pressed against the inner bottom surface of the lifter 38 via the retainer 39 and the lifter 38 is pressed against the drive cam 22.

  The position of the plunger 32 in the direction along the center line L (the length direction of the sliding hole 31) varies depending on the contact position of the drive cam 22 with the lifter 38. For example, when the drive cam 22 contacts the center C of the lifter 38 in the base circle portion 23, the plunger 32 is located at a position (bottom dead center) that is closest to the rotation center R of the camshaft 21 in the movable range. At this time, the plunger 32 is located at a place most retracted from the pressurizing chamber 35. Therefore, the volume of the pressurizing chamber 35 is the maximum of the range that can be taken.

On the other hand, when the drive cam 22 contacts the lifter 38 in the cam nose 24, the plunger 32 is positioned closer to the pressurizing chamber 35 than the bottom dead center in the movable range.
As shown in FIG. 7, when the drive cam 22 comes into contact with the center C of the lifter 38 at a position (tip portion) farthest from the base circle 23 of the predetermined cam nose 24, the plunger 32 moves within the movable range of the camshaft 21. Is located at the place farthest from the rotation center R (top dead center). At this time, the end portion (upper end portion in FIG. 7) of the plunger 32 is located at the most protruding portion in the pressurizing chamber 35. Therefore, the volume of the pressurizing chamber 35 is the smallest possible range. .

  As shown in FIG. 8, the volume of the pressurizing chamber 35 gradually increases during the stroke (intake stroke) in which the plunger 32 moves from the top dead center to the bottom dead center. Further, as shown in FIG. 6, the volume of the pressurizing chamber 35 gradually decreases during the stroke (pressurization stroke) in which the plunger 32 moves from the bottom dead center toward the top dead center.

  As shown in FIGS. 1 and 2, an electromagnetic spill valve 42 is incorporated in the high pressure fuel pump 17 in order to communicate or block between the low pressure fuel passage 16 and the pressurizing chamber 35. The electromagnetic spill valve 42 is fastened and fixed to the cover 33 by bolts 43. The electromagnetic spill valve 42 includes an electromagnetic solenoid. When the electromagnetic solenoid is not energized, the electromagnetic spill valve 42 is opened to allow communication between the low pressure fuel passage 16 and the pressurizing chamber 35. In addition, the electromagnetic spill valve 42 is closed when the electromagnetic solenoid is energized to shut off the low-pressure fuel passage 16 and the pressurizing chamber 35.

  The electromagnetic spill valve 42 is opened throughout the entire intake stroke in which the volume of the pressurizing chamber 35 increases. Therefore, the fuel 10 is sucked into the pressurizing chamber 35 from the low pressure fuel passage 16 during the suction stroke. Further, the electromagnetic spill valve 42 is generally closed at an arbitrary timing in a pressurizing stroke in which the volume of the pressurizing chamber 35 decreases. During the valve opening period until the electromagnetic spill valve 42 is closed in the pressurizing stroke, the fuel 10 in the pressurizing chamber 35 overflows into the low pressure fuel passage 16. During the valve closing period from the closing timing of the electromagnetic spill valve 42 to the end of the pressurizing stroke, the fuel 10 in the pressurizing chamber 35 is pressurized. When the pressure of the fuel 10 exceeds a specified value due to this pressurization, the check valve 37 is opened and the fuel 10 in the pressurizing chamber 35 is discharged to the high pressure fuel passage 36.

  Here, when the closing timing of the electromagnetic spill valve 42 in the pressurization stroke is changed, the amount of the fuel 10 overflowed from the pressurization chamber 35 to the low-pressure fuel passage 16 during the pressurization stroke changes. Therefore, it is possible to adjust the fuel discharge amount of the high-pressure fuel pump 17 by adjusting the valve closing timing of the electromagnetic spill valve 42.

  For example, if the valve closing timing is advanced through energization control of the electromagnetic spill valve 42 and the amount of the fuel 10 overflowing from the pressurizing chamber 35 to the low pressure fuel passage 16 is reduced during the pressurizing stroke, the electromagnetic spill in the pressurizing stroke is reduced. During the valve closing period of the valve 42, the amount of fuel 10 discharged from the pressurizing chamber 35 to the high pressure fuel passage 36 increases. When the plunger 32 reaches the bottom dead center, that is, when the electromagnetic spill valve 42 is closed at the timing of switching from the suction stroke to the pressurization stroke, the overflow flow rate of the fuel 10 is minimized, and the pressure chamber 35 to the high pressure fuel passage 36 is reached. The discharge amount is maximized.

  Further, if the valve closing timing is delayed through energization control of the electromagnetic spill valve 42 and the amount of the fuel 10 overflowing from the pressurizing chamber 35 to the low pressure fuel passage 16 during the pressurizing stroke is increased, the electromagnetic spill in the pressurizing stroke is increased. During the valve closing period of the valve 42, the amount of the fuel 10 discharged from the pressurizing chamber 35 to the high pressure fuel passage 36 is reduced.

  By the way, in the high pressure fuel pump 17 of the present embodiment, the closing timing of the electromagnetic spill valve 42 is set at the bottom dead center of the plunger 32 in order to improve the performance of the engine. With this setting, the electromagnetic spill valve 42 is closed when the volume of the pressurizing chamber 35 reaches the maximum range, and the fuel discharge amount of the high-pressure fuel pump 17 is maximized.

  As shown in FIGS. 1 and 3, at least a part of the high-pressure fuel pump 17 is located in the cylinder head, and an oil for lubricating a valve mechanism or the like in the cylinder head is provided around the high-pressure fuel pump 17. Is present. The contact portion of the drive cam 22 with the lifter 38 is lubricated and cooled by this oil. In addition, through holes 44 and 45 are provided in the outer peripheral walls of the lifter guide 27 and the lifter 38, and the oil that has entered the lifter 38 through these through holes 44 and 45 is used for the plunger 32 and the lifter 38. The contact area with the inner bottom is lubricated and cooled.

  Further, the gap between the plunger 32 and the wall surface 46 of the sliding hole 31 has an annular shape, and the fuel 10 flowing out from the pressurizing chamber 35 mainly when the volume of the pressurizing chamber 35 is reduced (pressurizing stroke). The flow passage 47 is a part. Then, when a part of the fuel 10 in the pressurizing chamber 35 passes through the flow passage 47, lubrication and cooling between the plunger 32 and the wall surface 46 of the sliding hole 31 are performed. The fuel 10 flowing through the flow passage 47 flows out from the open end 48 on the drive cam 22 side of the sliding hole 31, but oil is present in the lifter 38 as described above. In order to prevent the fuel 10 and oil from mixing with each other, a seal member 49 is attached to the inner peripheral surface of the seat 28. The seal member 49 has a substantially cylindrical shape, and is in close contact with the outer peripheral surface of the plunger 32 so as to be relatively slidable at an end portion (lower end portion in FIG. 3) on the drive cam 22 side. The space in the seal member 49 constitutes a storage chamber 51 that temporarily stores the fuel 10 that has flowed out from the open end 48. The storage chamber 51 is connected to the fuel tank 14 by a return passage 54 (see FIG. 1), and the fuel 10 in the storage chamber 51 is returned to the fuel tank 14 through the return passage 54.

  As shown in FIG. 1, a relief valve 52 is attached to the delivery pipe 12, and the relief valve 52 is connected to the fuel tank 14 via a relief passage 53. The relief valve 52 opens when the fuel pressure in the delivery pipe 12 becomes excessively high and exceeds a predetermined value. By opening the valve, the high-pressure fuel 10 in the delivery pipe 12 is returned to the fuel tank 14 through the relief passage 53.

  By the way, in the high pressure fuel pump 17 having the above-described configuration, as shown in FIG. 6, the driving is performed in the pressurizing stroke in which the lifter 38 is pushed up by the driving cam 22 and the plunger 32 is moved to the pressurizing chamber 35 side. The pushing force Fu of the cam 22 is generated as a force toward the pressurizing chamber 35 side. In addition, when the pressure of the fuel 10 in the pressurizing chamber 35 is increased as the plunger 32 moves, the reaction force Fr is generated as a force toward the drive cam 22 side. The contact point Pa of the drive cam 22 with the lifter 38 is displaced with the rotation of the drive cam 22 and deviates from the center C of the lifter 38, which causes the lifter 38 to be within a range allowed by the clearance with the lifter guide 27. Tilt. At this time, the plunger 32 is tilted in a specific direction within the sliding hole 31 by the moment, that is, in the clockwise direction of FIG. A force (lateral force Fs) is applied from the inclined plunger 32 to the pressurizing chamber side end Ep and the drive cam side end Ed of the sliding hole 31.

  In particular, in the high-pressure fuel pump 17 of the present embodiment, as described above, the closing timing of the electromagnetic spill valve 42 is set so as to increase the discharge amount or fuel pressure of the fuel 10 in order to improve the performance of the engine. The bottom dead center is set. However, with this setting, the reaction force Fr due to the pressure increase of the fuel 10 becomes large at the initial stage of the pressurization stroke, and the lateral force Fs increases. As a result, at the pressurizing chamber side end Ep and the drive cam side end Ed of the sliding hole 31, the surface pressure due to the plunger 32 increases, and the amount of heat generated by the sliding of the plunger 32 increases, thereby suppressing seizure. In order to do so, a large amount of fuel 10 is required.

  In this regard, the pressurizing chamber side end Ep near the pressurizing chamber 35 has a large volume of the fuel 10 in the pressurizing chamber 35, and therefore the pressurizing chamber side end Ep is lubricated. Heat dissipation is encouraged. However, the drive cam side end Ed far from the pressurizing chamber 35 is not supplied with an appropriate amount of fuel 10 through the flow passage 47, and the drive cam side end Ed may not be sufficiently lubricated and cooled.

  Therefore, in the present embodiment, the following measures are taken so that the drive cam side end portion Ed is reliably lubricated and cooled in the pressurization stroke. As shown in FIGS. 4 and 5, the wall 46 of the sliding hole 31 has a single fuel holding groove as a liquid holding recess for temporarily holding the fuel 10 flowing in the flow passage 47 in the vicinity of the drive cam side end portion Ed. 55 is provided. In the vicinity of the drive cam side end portion Ed, as described above, the plunger 32 contacts with the highest surface pressure during sliding. The fuel holding groove 55 is formed around the entire circumference of the wall surface 46 around the center line L of the sliding hole 31 and has an annular shape.

  Here, in the pressure stroke, the plunger 32 contacts with the uniform strength over the entire circumference of the wall surface 46 of the sliding hole 31 when tilting with respect to the sliding hole 31 and contacting the driving cam side end portion Ed. However, a lot of heat is generated due to strong contact with a specific part.

  On the other hand, in the first embodiment, the fuel holding groove 55 is formed on the basis of the surface P (see FIG. 3) passing through the rotation center R of the cam shaft 21 and the center line L of the sliding hole 31 described above. It is divided into two regions that are partitioned by the surface P. One region is a contact side region Tdc on the side in contact with the wall surface 46 of the sliding hole 31 (on the left side of the surface P in FIGS. 4 and 5) in the pressurization stroke in which the plunger 32 moves to the pressurizing chamber 35 side. It is. The contact side region Tdc has an arc shape (substantially semicircular ring shape) and corresponds to a portion where the amount of heat generated by the sliding of the plunger 32 is particularly large.

  The other region is a non-contact side region Tdn on the side where the plunger 32 does not contact the wall surface 46 in the pressurization stroke (on the right side of the surface P in FIGS. 4 and 5). The non-contact side region Tdn has an arcuate shape (substantially semicircular) and corresponds to a location where the amount of heat generated by sliding of the plunger 32 is smaller than that of the contact side region Tdc.

  As shown by hatching in FIG. 4, in the contact side region Tdc, the sectional area of the surface including the center line L is Sdc, and the sectional area of the non-contact side region Tdn on the surface including the center line L is Sdn. Then, both regions Tdc and Tdn are formed so as to satisfy the relationship of “Sdc> Sdn”.

  Specifically, the bottom surface 56 of the fuel holding groove 55 is formed in parallel with the center line L of the sliding hole 31 at any location in the circumferential direction. Further, the opposing side surfaces 57 and 58 of the fuel holding groove 55 are orthogonal to the center line L at any circumferential position. Accordingly, the fuel holding groove 55 has a rectangular cross-sectional shape at any location in the circumferential direction. Further, when the width of the contact side region Tdc (the length in the direction along the center line L of the sliding hole 31) is Wdc and the width of the non-contact side region Tdn is Wdn, both widths Wdc and Wdn are “Wdc = The relationship of “Wdn” is satisfied.

  Furthermore, when the depth of the contact side region Tdc is Ddc and the depth of the non-contact side region Tdn is Ddn, both depths Ddc and Ddn satisfy the relationship of “Ddc> Ddn”. Thus, the fuel holding groove 55 is formed deeper in the contact side region Tdc than in the non-contact side region Tdn.

  In order to realize the fuel holding groove 55 having the above various relationships, the fuel holding groove 55 is formed in a state where the center line L1 is eccentric with respect to the center line L of the sliding hole 31, as shown in FIG. ing. The eccentric direction of the center line L1 with respect to the center line L is based on the boundary portion (surface P) between the two regions Tdc and Tdn. The left side of FIG.

  With this configuration, the depth Ddc (cross-sectional area Sdc) of the contact side region Tdc is minimized at the boundary portion (surface P) and gradually increases as the distance from the boundary portion (surface P) increases. The same depth Ddc (cross-sectional area Sdc) becomes maximum at a position farthest from the boundary portion (plane P). Further, the depth Ddn (cross-sectional area Sdn) of the non-contact side region Tdn is maximized at the boundary portion (surface P) and gradually decreases as the distance from the boundary portion (surface P) increases. The same depth Ddn (cross-sectional area Sdn) is the smallest at a position farthest from the boundary portion (plane P).

  In addition, as shown in FIG. 8, the plunger 32 is inclined in the opposite direction to the pressurizing stroke, in this case, in the counterclockwise direction, in the suction stroke moving to the drive cam 22 side. At this time, the reaction force Fr described above is small, and accordingly, the lateral force Fs is small. Therefore, the problem of heat generation and seizure due to the sliding of the plunger 32 such as the pressurization stroke is unlikely to occur.

  In the high-pressure fuel pump 17 of the present embodiment configured as described above, the plunger 32 is driven by the rotating drive cam 22 and reciprocates in the slide hole 31. As shown in FIG. 8, in the suction stroke in which the plunger 32 is moved to the drive cam 22 side, the volume of the pressurizing chamber 35 increases, and the fuel 10 is sucked therein. On the other hand, as shown in FIG. 6, in the pressurization stroke in which the plunger 32 is moved to the pressurization chamber 35 side, the volume of the pressurization chamber 35 decreases and the fuel 10 inside thereof is pressurized. With this pressurization, part of the fuel 10 in the pressurizing chamber 35 flows out to the flow passage 47. Lubrication / cooling between the plunger 32 and the wall surface 46 of the sliding hole 31 is performed by the fuel 10 flowing through the flow passage 47.

  In particular, in the first embodiment in which the fuel holding groove 55 is provided in the vicinity of the drive cam side end Ed on the wall surface 46, a part of the fuel 10 in the pressurizing chamber 35 that has flowed out into the flow passage 47 in the pressurizing stroke is obtained. In the course of flowing through the flow passage 47, the fuel is temporarily held in the fuel holding groove 55. In the flow passage 47, the volume of the fuel 10 is larger at the driving cam side end Ed where the fuel holding groove 55 is provided in the vicinity than at other portions.

  For this reason, even when the plunger 32 comes into sliding contact with the wall surface 46 of the sliding hole 31 at the highest surface pressure against the drive cam side end portion Ed, the contact portion and the vicinity of the drive cam side end portion Ed Heat exchange is efficiently performed with the fuel 10 having a large volume in the fuel holding groove 55 provided in

  In the first embodiment, the cross-sectional areas Sdc and Sdn of the fuel holding groove 55 are not the same in the circumferential direction, and the cross-sectional area Sdc of the contact side region Tdc is set larger than the cross-sectional area Sdn of the non-contact side region Tdn. (See FIG. 4). With this setting, the amount of the fuel 10 held in the fuel holding groove 55 is large in the contact side region Tdc and small in the non-contact side region Tdn. In the fuel holding groove 55, the volume of the fuel 10 in contact with the drive cam side end portion Ed of the plunger 32 and the sliding hole 31 is large in the contact side region Tdc and small in the non-contact side region Tdn. The contact side region Tdc has a larger amount of heat exchange with the fuel 10 than the non-contact side region Tdn, and the drive cam side end Ed and the like are efficiently lubricated and cooled in the contact side region Tdc.

According to the first embodiment described in detail above, the following effects can be obtained.
(1) A fuel retaining groove 55 is provided in the vicinity of the drive cam side end Ed on the wall surface 46 of the sliding hole 31 and flows out into the flow passage 47 in the pressurization stroke in which the plunger 32 is moved to the pressurization chamber 35 side. A part of the fuel 10 in the pressurizing chamber 35 is temporarily held in the fuel holding groove 55 (see FIG. 6). Therefore, lubrication and cooling of the drive cam side end Ed can be enhanced by the fuel 10 having a large volume in the fuel holding groove 55, and the sliding of the plunger 32 is caused as compared with the case where there is no such fuel holding groove 55. Burn-in due to heat generation can be reliably suppressed.

  (2) The fuel holding groove 55 is divided into a contact side region Tdc that generates a large amount of heat when the plunger 32 slides and a non-contact side region Tdn that does not generate as much heat as the contact side region Tdc. The sectional area Sdc of the region Tdc is set larger than the sectional area Sdn of the non-contact side region Tdn (see FIGS. 4 and 5). With this setting, the volume of the fuel 10 that contacts the drive cam side end Ed of the plunger 32 and the sliding hole 31 in the fuel holding groove 55 is increased in the contact side region Tdc and decreased in the non-contact side region Tdn. .

  Accordingly, the portion having a large calorific value is exceeded by the fuel 10 in the contact side region Tdc having a large cross-sectional area Sdc, and the portion having a small calorific value is indicated by the fuel 10 in the non-contact side region Tdn having a small cross-sectional area Sdn. Lubrication and cooling can be performed without any shortage.

  (3) The plunger 32 does not contact with a uniform strength over the entire circumference of the wall surface 46 of the sliding hole 31, and a specific portion of the contact side region Tdc, that is, a boundary portion (surface P) in the contact side region Tdc. A lot of heat is generated in contact with the point farthest away from the strongest point. As the distance from this portion increases, the surface pressure decreases and the amount of heat generation decreases.

  In this regard, in the first embodiment, the depth Ddc (cross-sectional area Sdc) of the contact side region Tdc is gradually increased as the distance from the boundary portion (plane P) with the non-contact side region Tdn increases. Further, the depth Ddn (cross-sectional area Sdn) of the non-contact side region Tdn is gradually reduced as the distance from the boundary portion (surface P) with the contact side region Tdc increases. Therefore, the cross-sectional area in the circumferential direction of each region Tdc, Tdn can be set to a size corresponding to the amount of heat generated by the sliding of the plunger 32, and a part of the fuel 10 in the pressurizing chamber 35 that has flowed into the flow passage 47. Can be distributed and held in an amount corresponding to the degree of heat generation, and the fuel 10 can be lubricated and cooled without excess or deficiency.

(Second Embodiment)
Next, a second embodiment embodying the present invention will be described with reference to FIGS.

  In the pressurization stroke in which the plunger 32 is moved to the pressurizing chamber 35 side by the drive cam 22 and the pressure of the fuel 10 in the pressurizing chamber 35 is increased, the plunger 32 has a length of the sliding hole 31 in the cylinder body 29. As described above, in addition to the driving cam side end portion Ed, the pressurizing chamber side end portion Ep is contacted with the highest surface pressure as described above. At the pressurizing chamber side end Ep of the sliding hole 31, although the volume of the fuel 10 in the pressurizing chamber 35 is large and heat dissipation is promoted, the amount of heat generated by the sliding of the plunger 32 is larger than in other portions. Then, it is the same as the drive cam side end portion Ed. Therefore, in the pressurizing chamber side end portion Ep, a larger amount of fuel 10 is required than other portions in order to suppress seizure.

  Therefore, in the second embodiment, as the liquid holding recess, the fuel holding groove 55 is provided in the vicinity of the drive cam side end portion Ed of the wall surface 46 of the sliding hole 31 and the fuel is provided in the vicinity of the pressurizing chamber side end portion Ep. A holding groove 61 is provided.

  The fuel holding groove 61 is formed over the entire circumference of the wall surface 46 around the center line L of the sliding hole 31 and has an annular shape. The bottom surface 62 of the fuel holding groove 61 is parallel to the center line L at any location in the circumferential direction. Further, the opposite side surfaces 63 and 64 of the fuel holding groove 61 are orthogonal to the center line L at any location in the circumferential direction. Therefore, the fuel holding groove 61 has a rectangular cross-sectional shape at any location in the circumferential direction. In other words, if the cross-sectional area of the fuel holding groove 61 is Sp, as shown by the shaded area in the upper part of FIG. 10, this cross-sectional area Sp is the same everywhere in the circumferential direction. Further, when the depth of the fuel holding groove 61 is Dp and the width is Wp, the depth Dp and the width Wp are the same at any location in the circumferential direction of the fuel holding groove 61.

  On the other hand, the fuel holding groove 55 is formed over the entire circumference of the wall surface 46 around the center line L of the sliding hole 31 and has an annular shape. The bottom surface 56 of the fuel holding groove 61 is parallel to the center line L at any location in the circumferential direction. Further, the opposing side surfaces 57 and 58 of the fuel holding groove 55 are orthogonal to the center line L at any circumferential position. Accordingly, the fuel holding groove 55 has a rectangular cross-sectional shape at any location in the circumferential direction. In other words, as shown by hatching in the lower part of FIG. 10, when the cross-sectional area of the fuel holding groove 55 is Sd, the cross-sectional area Sd is the same at any location in the circumferential direction. Further, assuming that the depth of the fuel holding groove 55 is Dd and the width is Wd, the depth Dd and the width Wd are the same at any location in the circumferential direction of the fuel holding groove 55.

  Furthermore, both the fuel holding grooves 61 and 55 are formed so that the relationship of “Sp <Sd” is satisfied with respect to the cross-sectional areas Sp and Sd. In order to establish this relationship, in this embodiment, the width Wd of the fuel holding groove 55 and the width Wp of the fuel holding groove 61 are set to be the same, and the depth Dd of the fuel holding groove 55 is the depth of the fuel holding groove 61. It is set to be larger than Dp.

Other configurations are the same as those in the first embodiment. For this reason, the same parts and members as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.
As described above, the fuel holding groove 61 is provided on the wall surface 46 of the sliding hole 31 in the vicinity of the pressurizing chamber side end portion Ep in addition to the vicinity of the driving cam side end portion Ed. Then, the fuel 10 is temporarily held in the fuel holding grooves 61 and 55 in the process of flowing through the flow passage 47. In the flow passage 47, the pressurization chamber side end Ep provided near the fuel holding groove 61 and the drive cam side end Ed provided near the fuel holding groove 55 have more fuel 10 than other portions. Volume increases. Therefore, heat exchange is efficiently performed between the pressurizing chamber side end portion Ep and the driving cam side end portion Ed with which the plunger 32 contacts with the highest surface pressure, and the many fuels 10 in the fuel holding grooves 61 and 55. Is called.

  In the second embodiment, since the cross-sectional area Sd of the fuel holding groove 55 is larger than the cross-sectional area Sp of the fuel holding groove 61, the fuel 10 flowing through the flow passage 47 flows through the fuel holding groove 61 on the pressurizing chamber 35 side. More than that, the fuel is retained in the fuel retaining groove 55 on the drive cam 22 side. The volume of the fuel 10 that comes into contact with the plunger 32 at both ends of the sliding hole 31 is larger at the driving cam side end Ed than at the pressurizing chamber side end Ep.

Therefore, according to the second embodiment, in addition to the above (1), the following effects can be obtained.
(4) With respect to the wall surface 46 of the sliding hole 31, in addition to the fuel holding groove 55 in the vicinity of the driving cam side end portion Ed, the fuel holding groove 61 is provided in the vicinity of the pressurizing chamber side end portion Ep. The volume of the fuel 10 is made larger than other portions (see FIG. 9). Therefore, lubrication and cooling of the drive cam side end Ed and the pressurization chamber side end Ep can be enhanced by the fuel 10 having a large volume in the fuel holding grooves 55 and 61. Even if the plunger 32 contacts the pressurizing chamber side end portion Ep and the drive cam side end portion Ed with a high surface pressure with respect to the wall surface 46 of the sliding hole 31 in the pressurizing stroke, the contact portion and the end portion Ep , Ed can efficiently exchange heat with many fuels 10 in the fuel holding grooves 61 and 55 provided in the vicinity of Ed. Of course, the seizure due to heat generated by sliding of the plunger 32 can be more reliably suppressed as compared with the case where only the fuel holding groove 55 is provided, as well as the case where no fuel holding grooves 55 and 61 are provided. It becomes like this.

  (5) The cross-sectional area Sd of the fuel holding groove 55 provided in the vicinity of the drive cam side end portion Ed is set larger than the cross-sectional area Sp of the fuel holding groove 61 provided in the vicinity of the pressurizing chamber side end portion Ep. (See FIG. 10). By such setting, the fuel 10 flowing through the flow passage 47 is distributed and held more in the fuel holding groove 55 on the driving cam 22 side than the fuel holding groove 61 on the pressurizing chamber 35 side, and both end portions Ed, The volume of the fuel 10 that comes into contact with the plunger 32 at Ep is set larger at the driving cam side end Ed than at the pressurizing chamber side end Ep.

  For this reason, about the pressurization chamber side end part Ep of the sliding hole 31 in which heat dissipation is promoted by the fuel 10 in the pressurization chamber 35, the heat is also dissipated by the fuel 10 in the fuel holding groove 61 having a small cross-sectional area Sp. The driving cam side end Ed having a small acceleration effect can be lubricated and cooled by the fuel 10 in the fuel holding groove 55 having a large cross-sectional area Sd.

Note that the present invention can be embodied in another embodiment described below.
In the first embodiment, the depth Ddc of the contact side region Tdc is set to the non-contact side as a configuration in which the cross-sectional area Sdc of the contact side region Tdc in the fuel holding groove 55 is larger than the cross-sectional area Sdn of the non-contact side region Tdn. It was set larger than the depth Ddn of the region Tdn. Instead, as shown in FIGS. 11 and 12, the width Wdc of the contact-side region Tdc may be set larger than the width Wdn of the non-contact-side region Tdn under “Ddc = Ddn”. In this case, the width Wdc of the contact side region Tdc may be minimized at the boundary portion (surface P) with the non-contact side region Tdn and gradually increased as the distance from the boundary portion increases. Similarly, the width Wdn of the non-contact side region Tdn may be maximized at a boundary portion (surface P) with the contact side region Tdc and gradually decreased as the distance from the boundary portion increases.

  11 shows that the side surface 58 of the contact side region Tdc and the side surface 58 of the non-contact side region Tdn are located on the same plane orthogonal to the center line L, and the side surface 57 of the contact side region Tdc and the non-contact side region An example is shown in which the side surface 57 of Tdn is located on a different surface.

  In FIG. 12, the side surface 58 of the contact side region Tdc and the side surface 58 of the non-contact side region Tdn are located on different surfaces, and the side surface 57 of the contact side region Tdc and the side surface 57 of the non-contact side region Tdn are The example which is located on a mutually different surface is shown.

In the example of FIG. 11 and the example of FIG. 12 described above, the relationship “Sdc> Sdn” is established between the cross-sectional areas Sdc and Sdn.
Further, as shown in FIGS. 13 and 14, the contact side region Tdc of the fuel holding groove 55 is provided in a state of being arranged in the length direction of the sliding hole 31 and is more in number than the non-contact side region Tdn. You may comprise by many groove part 55A, 55B. 13 and 14 show an example in which one groove portion 55A is provided in the non-contact side region Tdn, and two groove portions 55A and 55B are provided in the contact side region Tdc. The groove portion 55A of the non-contact side region Tdn and the groove portion 55A of the contact side region Tdc are both arcuate (substantially semicircular), and are connected to the mating groove portion 55A at both ends thereof. Both groove portions 55A and 55A have an annular shape as a whole.

  Further, the groove part 55B of the contact side region Tdc has an arc shape (substantially semi-annular) like the groove part 55A. The groove 55B can be obtained, for example, by processing an annular recess in the wall 46 as shown in FIG. In this case, the annular recess is made smaller in diameter than both grooves 55A and 55A, and the former center line L2 is decentered from the latter center line L3 (same as the center line L of the sliding hole 31). The eccentric direction of the center line L2 with respect to the center lines L3 and L is based on the boundary portion (surface P) between the two regions Tdc and Tdn, and the drive cam 22 contacts the lifter 38 in the pressurization stroke of the plunger 32 than that. This is the side (left side of FIG. 14). In this case, the sum of the cross-sectional areas of the groove portions 55A and 55B becomes the cross-sectional area Sdc of the fuel holding groove 55, and the relationship of “Sdc> Sdn” is established.

  With the above processing, a pair of groove portions 55C connected to both ends of the groove portion 55B is formed on the same surface as the groove portion 55B of the contact side region Tdc in the non-contact side region Tdn (see FIG. 14). However, these grooves 55C and 55C have a small volume and hardly exhibit an effect of enhancing lubrication and cooling. Therefore, the non-contact side region Tdn is substantially not provided with a groove portion corresponding to the groove portion 55B of the contact side region Tdc, and only the groove portion 55A is provided (that is, the number of groove portions is “1”). )

Although not shown, the following items (i) to (iii) may be combined as appropriate.
(I) The depth Ddc of the contact side region Tdc is made larger than the depth Ddn of the non-contact side region Tdn (see FIG. 4).

(Ii) The width Wdc of the contact side region Tdc is made larger than the width Wdn of the non-contact side region Tdn (see FIGS. 11 and 12).
(Iii) The contact-side region Tdc of the fuel holding groove 55 is configured by a larger number of grooves than the non-contact-side region Tdn (see FIG. 13).

  In the first embodiment, the cross-sectional area Sdc of the contact side region Tdc and the cross-sectional area Sdn of the non-contact side region Tdn may be set to be the same. In this case, the same effect as the above (1) can be obtained.

  In the second embodiment, the cross-sectional area Sd of the fuel holding groove 55 is configured to be larger than the cross-sectional area Sp of the fuel holding groove 61, and the depth Dd of the fuel holding groove 55 is greater than the depth Dp of the fuel holding groove 61. Was also set large (see FIG. 10). Alternatively, as shown in FIG. 15, the width Wd of the fuel holding groove 55 may be set larger than the width Wp of the fuel holding groove 61 under “Dd = Dp”.

  Further, as shown in FIG. 16, the fuel holding grooves 55 are provided in a state where they are arranged in the length direction of the sliding holes 31 (vertical direction in FIG. 16), and the number of the fuel holding grooves 55 is smaller than the groove portion 61A of the fuel holding groove 61. You may comprise by groove part 55A, 55B with much. However, the cross-sectional areas of the grooves 61A, 55A, and 55B are the same. FIG. 16 shows an example in which the fuel holding groove 61 is constituted by one groove portion 61A, and the fuel holding groove 55 is constituted by two groove portions 55A and 55B. In this case, the sum of the cross-sectional areas of the groove portions 55 </ b> A and 55 </ b> B becomes the cross-sectional area Sd of the fuel holding groove 55.

  The cross-sectional areas of the grooves 61A, 55A, and 55B may be changed on the condition that the relationship of “Sp <Sd” is established between the cross-sectional areas Sp and Sd. In this case, the cross-sectional areas of the groove portions 61A, 55A, and 55B may be different.

Although not shown, the following items (iv) to (vi) may be combined as appropriate.
(Iv) The depth Dd of the fuel holding groove 55 is made larger than the depth Dp of the fuel holding groove 61 (see FIG. 10).

(V) The width Wd of the fuel holding groove 55 is made larger than the width Wp of the fuel holding groove 61 (see FIG. 15).
(Vi) The fuel holding groove 55 is constituted by a groove having a larger number than the fuel holding groove 61 (see FIG. 16).

  -As shown in FIGS. 17-19, you may implement combining the content of 1st Embodiment, and the content of 2nd Embodiment. That is, with respect to the wall surface 46 of the sliding hole 31, the fuel holding groove 55 is provided in the vicinity of the driving cam side end portion Ed, and the fuel holding groove 61 is provided in the vicinity of the pressurizing chamber side end portion Ep. The cross-sectional area Sdc of the contact side region Tdc in the fuel holding groove 55 is set larger than the cross-sectional area Sp of the fuel holding groove 61 and the cross-sectional area Sdn of the non-contact side region Tdn. When combined in this way, the effects (1) to (5) described above can be obtained. In particular, the cross-sectional area of each part of the fuel holding grooves 55 and 61 can be set to a size corresponding to the amount of heat generated by the sliding of the plunger 32, and a part of the fuel 10 in the pressurizing chamber 35 that has flowed into the flow passage 47. Can be distributed and held in an amount corresponding to the degree of heat generation, and the fuel 10 can be lubricated and cooled without excess or deficiency.

17 to 19, as a common matter, the cross-sectional area Sdn of the non-contact side region Tdn is set to be the same as the cross-sectional area Sp of the fuel holding groove 61 on the pressurizing chamber 35 side.
17 to 19 are different from each other in the configuration in which the cross-sectional area Sdc of the contact side region Tdc in the fuel holding groove 55 is larger than the cross-sectional area Sdn (= Sp) of the non-contact side region Tdn. In FIG. 17, the depth Ddc of the contact side region Tdc is set larger than the depth Ddn of the non-contact side region Tdn under “Wdc = Wdn”.

  In FIG. 18, the width Wdc of the contact side region Tdc is set larger than the width Wdn of the non-contact side region Tdn under “Ddc = Ddn”. In this case, similarly to FIG. 12 described above, the width Wdc of the contact side region Tdc is minimized at the boundary portion (surface P) with the non-contact side region Tdn and gradually increased as the distance from the boundary portion increases. Also good. Similarly, the width Wdn of the non-contact side region Tdn may be maximized at a boundary portion (surface P) with the contact side region Tdc and gradually decreased as the distance from the boundary portion increases.

  In FIG. 19, the contact side region Tdc of the fuel holding groove 55 is provided in a state of being arranged in the length direction of the sliding hole 31 (vertical direction in FIG. 19), and has a larger number than the non-contact side region Tdn. It is comprised by the groove parts 55A and 55B. FIG. 19 shows an example in which the non-contact side region Tdn is configured by one groove portion 55A and the contact side region Tdc is configured by two groove portions 55A and 55B. In this case, the sum of the cross-sectional areas of the grooves 55A and 55B becomes the cross-sectional area Sd of the contact side region Tdc, and the relationship of “Sdc> Sdn” is established.

Further, although not shown, the items of “depth”, “width”, and “number of grooves” in FIGS. 17 to 19 may be appropriately combined.
Of the wall surface 46 of the sliding hole 31, the latter (pressure chamber side end portion Ep) of the drive cam side end portion Ed and the pressure chamber side end portion Ep where the plunger 32 slides at a high surface pressure. The fuel holding groove 61 may be provided only in the vicinity of.

  In the embodiment in which the fuel holding groove 61 is provided in the vicinity of the pressurizing chamber side end portion Ep, as in the fuel holding groove 55, the contact on the side where the plunger 32 contacts the wall surface 46 of the sliding hole 31 in the pressurizing stroke. The cross-sectional area of the contact-side area may be set larger than the cross-sectional area of the non-contact-side area.

  -You may change the cross-sectional shape of the fuel holding grooves 55 and 61 into the shape different from each said embodiment. For example, the bottom surfaces 56 and 62 may be inclined with respect to the center line L. Further, the side surfaces 57, 58, 63, and 64 may be configured by surfaces that intersect with the center line L obliquely (except for orthogonality). Furthermore, the cross-sectional shape may be changed to a shape other than a rectangle, such as a triangular shape or a semicircular shape.

The present invention can also be applied to a high-pressure fuel pump that closes after the electromagnetic spill valve 42 slightly passes the bottom dead center in the pressurization stroke.
The present invention can be applied to a high pressure pump other than the high pressure fuel pump 17 of the engine.

  The drive cam 22 may be provided separately from the cam shaft 21 of the engine, and the plunger 32 may be slid back and forth by the drive cam 22.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram which shows the fuel supply system using the high-pressure fuel pump of 1st Embodiment which actualized this invention. Sectional drawing which shows the internal structure of the high pressure fuel pump in FIG. Sectional drawing which expands and shows the A section in FIG. Sectional drawing which expands and shows the B section in FIG. CC sectional view taken on the line in FIG. Sectional drawing which shows the state of A part about the high pressure fuel pump when a drive cam rotates further from the state of FIG. 3, and a plunger raises (pressurization process). Sectional drawing which shows the state of A part about a high pressure fuel pump when a drive cam rotates further from the state of FIG. 6, and a plunger reaches the top dead center. Sectional drawing which shows the state of A part about a high pressure fuel pump when a drive cam rotates further from the state of FIG. 7, and a plunger descends (inhalation stroke). Sectional drawing which shows the internal structure of a high pressure fuel pump corresponding to the A section of FIG. 3 in 2nd Embodiment which actualized this invention. Sectional drawing which expands and shows the D section in FIG. Sectional drawing which shows another embodiment of a fuel holding groove in the B section of FIG. FIG. 5 is a cross-sectional view showing another embodiment of the fuel holding groove, similarly in the portion B of FIG. 4. FIG. 5 is a cross-sectional view showing another embodiment of the fuel holding groove, similarly in the portion B of FIG. 4. EE sectional view taken on the line in FIG. Sectional drawing which shows another embodiment of a fuel holding groove in the D section of FIG. FIG. 11 is a cross-sectional view showing another embodiment of the fuel holding groove, similarly in the D part of FIG. 10. FIG. 11 is a cross-sectional view showing another embodiment of the fuel holding groove, similarly in the D part of FIG. 10. FIG. 11 is a cross-sectional view showing another embodiment of the fuel holding groove, similarly in the D part of FIG. 10. FIG. 11 is a cross-sectional view showing another embodiment of the fuel holding groove, similarly in the D part of FIG. 10. Sectional drawing of the high-pressure fuel pump in background art. Sectional drawing which expands and shows the F section in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Fuel (liquid), 17 ... High pressure fuel pump (high pressure pump), 22 ... Drive cam, 29 ... Cylinder body, 31 ... Sliding hole, 32 ... Plunger, 35 ... Pressurizing chamber, 46 ... Wall surface of sliding hole , 47 ... flow passage, 55, 61 ... fuel holding groove (liquid holding recess), 55A, 55B, 61A ... groove, Dd, Ddc, Ddn, Dp ... depth, Ed ... drive cam side end, Ep ... pressurization Chamber side end, Sd, Sdc, Sdn, Sp ... cross-sectional area, Tdc ... contact side region, Tdn ... non-contact side region, Wd, Wdc, Wdn, Wp ... width.

Claims (11)

A plunger is slidably inserted into a sliding hole of the cylinder body between the pressurizing chamber and the drive cam, and the plunger is moved to the drive cam side by the drive cam to suck liquid into the pressurization chamber. The plunger is moved toward the pressurizing chamber by the drive cam to pressurize the liquid in the pressurizing chamber, and further, the gap between the plunger and the wall surface of the sliding hole flows out of the pressurizing chamber. In the high-pressure pump used as the liquid flow path,
A high-pressure pump characterized in that, on the wall surface of the sliding hole, a liquid holding recess for temporarily holding the liquid flowing through the flow passage is provided in the vicinity of a location where the plunger contacts with high surface pressure as it slides. The high-pressure pump according to claim 1, wherein the liquid holding recess is provided in the vicinity of an end portion on a drive cam side of the wall surface of the sliding hole. The liquid holding recess is formed in the circumferential direction of the wall surface of the sliding hole, and the liquid holding recess is on the side that contacts the wall surface of the sliding hole when the plunger moves to the pressurizing chamber side. 3. The high-pressure pump according to claim 2, wherein the contact-side region has a larger cross-sectional area than the non-contact-side region when divided into a contact-side region and a non-contact-side region on the non-contact side. The high-pressure pump according to claim 3, wherein the liquid holding recess is formed deeper in the contact side region than in the non-contact side region. The high-pressure pump according to claim 3 or 4, wherein the liquid holding recess is formed wider in the contact side region than in the non-contact side region. 4. The high-pressure pump according to claim 3, wherein the contact side region is provided in a state of being arranged in a length direction of the sliding hole, and is configured by a larger number of grooves than the non-contact side region. The high-pressure pump according to claim 2, wherein the liquid holding recess is provided in the vicinity of the end portion on the pressurizing chamber side in addition to the vicinity of the end portion on the drive cam side of the wall surface of the sliding hole. The high pressure pump according to claim 7, wherein the liquid holding recess located in the vicinity of the driving cam side end has a larger cross-sectional area than the liquid holding recess located in the vicinity of the pressurizing chamber side end. The high pressure pump according to claim 8, wherein the liquid holding recess located in the vicinity of the driving cam side end is formed deeper than the liquid holding recess located in the vicinity of the pressurizing chamber side end. 10. The high-pressure pump according to claim 8, wherein the liquid holding recess located in the vicinity of the driving cam side end is formed wider than the liquid holding recess located in the vicinity of the pressurizing chamber end. The liquid holding recess located in the vicinity of the drive cam side end is provided in a state of being arranged in the length direction of the sliding hole, and moreover than the liquid holding recess located in the vicinity of the pressurizing chamber side end. The high-pressure pump according to claim 8, wherein the high-pressure pump is configured by a large number of grooves.

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