JP5029477B2 - Roller lifter structure - Google Patents

Description

  The present invention relates to a structure of a roller lifter provided in, for example, a fuel pump. In particular, the present invention relates to measures for realizing a smooth operation of the roller lifter.

  In-cylinder direct injection engines mounted on automobiles and the like, fuel injection must be performed with the fuel pressure higher than the pressure in the combustion chamber. Therefore, the fuel sent from the fuel tank is added by a high-pressure fuel pump. The pressure is supplied to the injector.

  As a fuel supply system of a direct injection type in-cylinder engine, for example, as disclosed in Patent Document 1 and Patent Document 2 below, a feed pump that feeds fuel from a fuel tank, and fuel that is fed by this feed pump A high pressure fuel pump that pressurizes the fuel, a delivery pipe that stores fuel pressurized by the high pressure fuel pump, and an injector disposed for each cylinder of the engine are known. By the valve opening control of each injector, the high-pressure fuel stored in the delivery pipe is directly injected from the injector into the combustion chamber.

  As a high-pressure fuel pump used in such a fuel supply system, for example, a plunger inserted in a cylinder so as to be reciprocally slidable, a pressurizing chamber defined by the cylinder and the plunger, a lifter guide Some of them include a lifter connected to the plunger and a compression coil spring that presses the lifter toward the outer peripheral surface of the cam. As the cam rotates, the plunger moves when the cam nose retreats from the lifter (the suction stroke), and the lifter is pushed by the cam nose, and the plunger moves accordingly. By repeating the process of reducing the volume of the pressurizing chamber (pressurizing process), the fuel is pressurized and supplied to the delivery pipe or the like.

By the way, in the high-pressure fuel pump having the structure as described above, the lifter is configured as a roller lifter as disclosed in Patent Document 2 in order to suppress sliding resistance between the cam and the lifter that are in contact with each other. Things are known. That is, a through-hole penetrating in the direction along the axis of the cam is formed in the substantially cylindrical lifter body, and the roller shaft is inserted and fixed in the through-hole, and the roller is rotatable by the roller shaft. It has a configuration that supports it. As a result, the outer peripheral surface of the roller and the outer peripheral surface of the cam come into contact with each other, and the lifter receives the pressing force from the cam while the roller rotates along the outer peripheral surface of the cam. The sliding resistance can be suppressed.
JP 2000-145572 A JP 2008-38604 A

By the way, in the conventional roller lifter, the following two phenomena have occurred due to the fact that the lifter is disposed in the lifter guide so as to be reciprocally movable.
(1) Lifter Cocking First, when the lifter receives a pressing force from the cam, the contact position of the cam with the roller changes in accordance with the rotational phase of the cam. For this reason, the lifter receives a load (component force) in a direction substantially perpendicular to the reciprocating direction, and the lifter tilts inside the lifter guide due to this load. FIG. 12 shows a state where the lifter b is tilted inside the lifter guide c due to the pressing force from the cam a during the pressurizing stroke. This inclination is caused by the existence of a gap (hereinafter referred to as guide clearance) between the inner surface of the lifter guide c and the outer surface of the lifter b. The larger the guide clearance, the larger the inclination. When the lifter b is tilted in this way, the upper end on one side (right side in the figure) of the outer peripheral surface of the lifter b in the direction orthogonal to the axis of the lifter guide c (left and right direction in the figure) The edge b1 and the lower end edge b2 on the other side (the left side in the figure) are in a state of being in contact with the inner surface of the lifter guide c. On the contrary, during the suction stroke, the direction of the load (reaction force from the cam a) received by the lifter b from the cam a is switched, and the direction perpendicular to the axis of the lifter guide c on the outer peripheral surface of the lifter b. The lower end edge b3 on one side (the right side in the figure) and the upper end edge b4 on the other side (the left side in the figure) are respectively brought into contact with the inner surface of the lifter guide c. Such a situation is called cocking, and abnormal noise is generated at each piece contact portion, or sliding resistance at each piece contact portion becomes extremely large, which causes the smooth reciprocation of the lifter b to be hindered. .
(2) Roller per piece against the cam If the parallelism between the rotation axis of the cam and the rotation axis of the roller is not good, for example, the processing accuracy and assembly accuracy of each component are not sufficiently obtained. For this reason, when these parallelisms are not obtained satisfactorily, only one part of the outer peripheral surface of the roller comes into contact with the outer peripheral surface of the cam. FIG. 13 shows a state in which the rotational axis of the cam a is inclined, and the lifter b is slightly inclined as much as the guide clearance exists, but cannot follow the inclination of the cam a. Since the parallelism between the rotation axis and the rotation axis of the roller d is not obtained, only one end edge of the roller d (one end edge d1 in the axial direction of the roller d) comes into contact with the outer peripheral surface of the cam a. It shows the state. In such a situation, the surface pressure at the contact portion between the cam a and the roller d increases significantly, and in some cases, the outer peripheral surface of the cam a may be damaged such as pitching.

  The following measures can be taken for each of the above phenomena.

  First, as a means for suppressing cocking of the lifter, it is possible to reduce the guide clearance. That is, by reducing the guide clearance, the lifter is hardly tilted under the restriction of the inner surface of the lifter guide, thereby suppressing cocking.

  On the other hand, as a means for suppressing the contact of the roller with the cam, the guide clearance can be enlarged. In other words, by enlarging the guide clearance, the tilt of the lifter relative to the lifter guide is greatly allowed to follow the cam tilt, and the parallelism between the cam rotation axis and the roller rotation axis can be obtained. It is what you want to do.

  As described above, conventionally, only the technical idea of reducing the guide clearance to suppress the lifter cocking and increasing the guide clearance to suppress the one-sided contact of the roller with respect to the cam has been achieved. These measures are mutually exclusive, so they cannot coexist. That is, according to the conventional technical idea, it has been impossible to achieve both the suppression of the lifter cocking and the suppression of the contact of the roller with respect to the cam.

  The present invention has been made in view of such a point, and an object of the present invention is to provide a configuration capable of achieving both the suppression of lifter cocking in the roller lifter and the suppression of the one-sided contact of the roller with respect to the cam. There is.

-Principle of solving the problem-
The solution principle of the present invention devised to achieve the above object makes the allowable amount of inclination of the lifter with respect to the lifter guide different according to the phase in the circumferential direction of the lifter. In other words, by limiting the lifter tilt tolerance for the phase in the direction in which the cocking occurs, increasing the lifter tilt allowance for the phase in the direction that needs to follow the cam tilt, It is possible to achieve both suppression of lifter cocking and suppression of roller contact with the cam.

-Solution-
Specifically, the present invention relates to a roller that contacts the outer peripheral surface of the cam and receives a pressing force from the cam, and a lifter that rotatably supports the roller and is reciprocally accommodated in the internal space of the lifter guide. Assuming a roller lifter structure with With respect to this roller lifter structure, the lifter is provided with a lifter body formed in a substantially cylindrical shape. Then, at the phase position in the roller axial extension direction in the circumferential phase of the outer peripheral surface of the lifter body, the fitting length dimension in the reciprocating direction of the portion in contact with the inner surface of the lifter guide is set short, and this roller In addition to increasing the allowable tilt of the lifter relative to the lifter guide in the axial extension direction, the phase position in the direction perpendicular to the roller axial extension direction in the circumferential phase of the outer peripheral surface of the lifter body is on the inner surface of the lifter guide. Lifter tilt tolerance adjustment that limits the lifter tilt tolerance with respect to the lifter guide in the direction perpendicular to the roller axis extension direction by setting the fitting length dimension in the reciprocating direction of the contact portion to be longer Means are provided. That is, the lifter allowable tilt amount with respect to the lifter guide in the direction along the roller axis is configured to be larger than the lifter allowable tilt amount with respect to the lifter guide in the direction orthogonal to the roller axis. In other words, the lifter allowable tilt amount with respect to the lifter guide in the direction perpendicular to the roller axis is smaller than the lifter allowable tilt amount with respect to the lifter guide in the direction along the roller axis.

  Due to this specific matter, the allowable amount of lifter tilt relative to the lifter guide in the direction orthogonal to the roller axis is limited, thereby suppressing the occurrence of cocking of the lifter. In addition, the lifter tilt tolerance with respect to the lifter guide in the direction along the roller axis is increased, so that the lifter tilt can follow the cam tilt, and the cam rotation axis and the roller rotation axis can be made to follow. By obtaining a good degree of parallelism with the center, it is possible to suppress the contact of the roller against the cam. As described above, according to the present solution, it is possible to achieve both the suppression of lifter cocking and the suppression of the one-sided roller contact with the cam.

  In this case, the fitting length is perpendicular to the roller axis extending direction in the circumferential phase of the outer peripheral surface of the lifter body from the phase position in the roller axis extending direction in the circumferential phase of the outer peripheral surface of the lifter body. The length is gradually increased toward the phase position at.

  More specifically, the lifter tilt allowable amount adjusting means is configured by chamfering the outer peripheral edge portions at both ends in the axial direction of the lifter body. In other words, the chamfer dimension is set to be larger at the phase position in the roller axis extension direction in the circumferential phase of the outer peripheral surface of the lifter body, while in the direction orthogonal to the roller axis extension direction in the circumferential phase of the outer surface of the lifter body. The chamfer dimension is set small at the phase position.

  With these configurations, the lifter inclination is largely regulated by the inner surface of the lifter guide because the fitting length is long at the phase position in the direction perpendicular to the roller axis extension direction in the circumferential phase of the outer peripheral surface of the lifter body. In addition, the allowable amount of inclination of the lifter with respect to the lifter guide in the direction perpendicular to the axis of the roller is limited. On the contrary, since the fitting length dimension is short at the phase position in the roller axial extension direction in the circumferential phase of the outer peripheral surface of the lifter body, the limit of the lifter inclination by the inner surface of the lifter guide is small, and the roller shaft The lifter tilt tolerance relative to the lifter guide in the direction along the center is increased. In this way, it is possible to achieve both the suppression of the lifter cocking and the suppression of the contact of the roller with respect to the cam with a relatively simple configuration in which the fitting length dimensions are different.

  In the present invention, the allowable amount of inclination of the lifter with respect to the lifter guide is varied according to the phase in the circumferential direction of the lifter, thereby limiting the allowable amount of inclination of the lifter with respect to the phase in the direction in which the cocking occurs. For the phase in the direction that needs to follow the cam tilt, the lifter tilt tolerance is increased. Thereby, both the suppression of the cocking of the lifter and the suppression of the one-sided contact of the roller with respect to the cam can be achieved, and the generation of abnormal noise, the increase in sliding resistance, and the occurrence of cam pitching can be prevented.

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

  Below, the case where this invention is applied to the roller lifter of the high pressure fuel pump used for the in-cylinder direct injection type | mold multi-cylinder (for example, 6 cylinders) gasoline engine mounted in a motor vehicle is demonstrated.

-Fuel supply device 100-
Before describing the roller lifter configuration of the high-pressure fuel pump, a schematic configuration of the fuel supply apparatus 100 to which the high-pressure pump is applied will be described with reference to FIG.

  1 includes a feed pump 102 that feeds fuel from a fuel tank 101, and pressurizes the fuel fed by the feed pump 102 to the injectors 4, 4,... Of each cylinder (six cylinders). And a high-pressure fuel pump 1 that discharges toward the vehicle.

  The high-pressure fuel pump 1 includes a cylinder 21, a plunger 23, a pressurizing chamber 22, and an electromagnetic spill valve 30.

  The plunger 23 is driven by the rotation of a cam 111 attached to the intake camshaft 110 of the engine, and reciprocates in the cylinder 21. By the reciprocating movement of the plunger 23, the volume of the pressurizing chamber 22 is enlarged or reduced. In this embodiment, three cam peaks (cam noses) 112, 112, 112 are formed in the cam 111 with an angular interval of 120 ° around the rotation axis of the intake camshaft 110. The plunger 23 is pushed up by the three cam noses 112, 112, 112, and the plunger 23 moves in the cylinder 21.

  In this embodiment, since the engine is a 6-cylinder type, during each cycle of the engine, that is, while the crankshaft rotates twice, each of the injectors 4 provided for each cylinder once, for a total of 6 times. Fuel injection will be performed. In addition, for each cycle of the engine, the intake camshaft 110 rotates once, and the discharge operation from the high-pressure fuel pump 1 is performed three times.

  The pressurizing chamber 22 is partitioned by a plunger 23 and a cylinder 21. The pressurizing chamber 22 communicates with the feed pump 102 via the low pressure fuel pipe 104. The pressurizing chamber 22 communicates with a delivery pipe (pressure accumulating vessel) 106 through a high-pressure fuel pipe 105.

  Six injectors 4, 4,... Are connected to the delivery pipe. The delivery pipe 106 is provided with a fuel pressure sensor 161 that detects the fuel pressure (actual fuel pressure) inside the pipe. A return pipe 172 is connected to the delivery pipe 106 via a relief valve 171.

  The relief valve 171 opens when the fuel pressure in the delivery pipe 106 exceeds a predetermined pressure (for example, 13 MPa). By opening the relief valve 171, a part of the fuel stored in the delivery pipe 106 is returned to the fuel tank 101 via the return pipe 172. Thereby, an excessive increase in the fuel pressure in the delivery pipe 106 is prevented.

  Further, the return pipe 172 and the high-pressure fuel pump 1 are connected by a fuel discharge pipe 108 (shown by a broken line in FIG. 1), and the fuel leaked from the gap between the plunger 23 and the cylinder 21 of the high-pressure fuel pump 1 is sealed. The fuel is accumulated in the fuel storage chamber 6 in the upper part of the unit 5 and then returned to the fuel tank 101 from the fuel discharge pipe 108 connected to the fuel storage chamber 6.

  The low pressure fuel pipe 104 is provided with a filter 141 and a pressure regulator 142. The pressure regulator 142 returns the fuel in the low-pressure fuel pipe 104 to the fuel tank 101 when the fuel pressure in the low-pressure fuel pipe 104 exceeds a predetermined pressure (for example, 0.4 MPa). The fuel pressure is maintained below a predetermined pressure.

  Further, a pulsation damper 107 is provided in the low pressure fuel pipe 104, and the pulsation damper 107 suppresses fuel pressure pulsation in the low pressure fuel pipe 104 when the high pressure fuel pump 1 is operated. . Further, the high pressure fuel pipe 105 is provided with a check valve 151 for preventing the fuel discharged from the high pressure fuel pump 1 from flowing backward.

  The high-pressure fuel pump 1 is provided with an electromagnetic spill valve 30 for communicating or blocking between the low-pressure fuel pipe 104 and the pressurizing chamber 22. The electromagnetic spill valve 30 includes an electromagnetic solenoid 31 and opens and closes by controlling energization of the electromagnetic solenoid 31.

  Next, the opening / closing operation of the electromagnetic spill valve 30 will be described with reference to FIG.

  First, when the energization of the electromagnetic solenoid 31 is stopped, the electromagnetic spill valve 30 is opened by the elastic force of the compression coil spring 37, and the low pressure fuel pipe 104 and the pressurizing chamber 22 are in communication with each other. In this state, when the cam 111 rotates together with the intake camshaft 110 and the plunger 23 moves in the direction in which the volume of the pressurizing chamber 22 increases (in the direction in which the plunger 23 descends in FIG. 1) (intake stroke). The fuel delivered from the feed pump 102 is sucked into the pressurizing chamber 22 through the low-pressure fuel pipe 104.

  On the other hand, when the cam 111 rotates together with the intake camshaft 110 and the plunger 23 moves in the direction in which the volume of the pressurizing chamber 22 contracts (the direction in which the plunger 23 rises in FIG. 1) (pressurization stroke), When the electromagnetic spill valve 30 is closed against the elastic force of the compression coil spring 37 by energizing the electromagnetic solenoid 31, the low-pressure fuel pipe 104 and the pressurizing chamber 22 are disconnected, and the fuel in the pressurizing chamber 22 is blocked. When the pressure reaches a predetermined value, the check valve 40 is opened, and high-pressure fuel is discharged toward the delivery pipe 106 through the high-pressure fuel pipe 105.

  The fuel discharge amount in the high-pressure fuel pump 1 is adjusted by controlling the closing period of the electromagnetic spill valve 30 in the pressurization stroke. That is, if the closing time of the electromagnetic spill valve 30 is advanced and the closing period is lengthened, the fuel discharge amount increases. If the closing start time of the electromagnetic spill valve 30 is delayed and the closing period is shortened, the fuel discharge amount decreases. To come. In this manner, the fuel pressure in the delivery pipe 106 is controlled by adjusting the fuel discharge amount of the high-pressure fuel pump 1.

  Here, the pump duty DT which is a control amount for controlling the fuel discharge amount of the high-pressure fuel pump 1 (the valve closing start timing of the electromagnetic spill valve 30) will be described. This pump duty DT varies between 0% and 100%, and is a value related to the cam angle of the cam 111 of the intake camshaft 110 corresponding to the valve closing period of the electromagnetic spill valve 30.

Specifically, with respect to the cam angle of the cam 111, as shown in FIG. 2, the cam angle (maximum cam angle) corresponding to the maximum valve closing period of the electromagnetic spill valve 30 is θ _0, and the target of the maximum valve closing period is set. Assuming that the cam angle (target cam angle) corresponding to the fuel pressure is θ, the pump duty DT is represented by the ratio of the target cam angle θ to the maximum cam angle θ ₀ (DT = θ / θ ₀ ). Accordingly, the pump duty DT becomes closer to 100% as the valve closing period (closing timing) of the target electromagnetic spill valve 30 approaches the maximum valve closing period, and the target valve closing period approaches “0”. The value is closer to 0%.

  And as the pump duty DT approaches 100%, the valve closing start timing of the electromagnetic spill valve 30 adjusted based on the pump duty DT is advanced, and the valve closing period of the electromagnetic spill valve 30 becomes longer. As a result, the fuel discharge amount of the high-pressure fuel pump 1 increases and the actual fuel pressure increases. Further, as the pump duty DT approaches 0%, the valve closing start timing of the electromagnetic spill valve 30 adjusted based on the pump duty DT is delayed, and the valve closing period of the electromagnetic spill valve 30 is shortened. As a result, the fuel discharge amount of the high-pressure fuel pump 1 is reduced and the actual fuel pressure is lowered. The details of the procedure for calculating the pump duty DT are omitted here.

-Specific configuration of high-pressure fuel pump 1-
Next, a specific configuration of the high-pressure fuel pump 1 will be described with reference to FIG.

  The high-pressure fuel pump 1 illustrated in FIG. 3 is a plunger type pump, and includes a pump unit 20 provided in the housing 10, an electromagnetic spill valve 30, and a check valve 40.

  The pump unit 20 includes a cylinder 21, a pressurizing chamber 22, a plunger 23, and a lifter 51. The cylinder 21 is formed at the center of the housing 10, and a pressurizing chamber 22 is formed on the tip side (the upper end side in FIG. 3). The plunger 23 is a substantially cylindrical member, and is inserted into the cylinder 21 so as to be slidable in the axial direction (the vertical direction here).

  As shown in FIG. 4, the lifter 51 includes a substantially cylindrical lifter body 51a and a roller support portion 51b extending downward from the lower end of the lifter body 51a. The roller support portion 51b includes support plates 51e and 51e that are formed inside the outer peripheral edge of the lower surface of the lifter main body 51a and face each other.

  A partition wall portion 51c is integrally formed at an intermediate portion of the lifter body 51a in the axial direction (vertical direction in FIG. 3), and a base end portion (lower end portion) of the plunger 23 is formed in a space above the partition wall portion 51c. A retainer 26, a compression coil spring 27, and the like are accommodated. In addition, an inner space below the lifter body 51a (a portion below the partition wall portion 51c) and an inner space of the roller support portion 51b are configured as spaces for accommodating the rollers 53, and this roller support portion. 51 b supports the roller 53 that is rotatable about an axis extending parallel to the axis of the intake camshaft 110. The lower end of the roller 53 can come into contact with the outer peripheral surface of the cam 111. Thus, the lifter 51 and the roller 53 constitute a roller lifter.

  The roller 53 is rotatably supported by, for example, a roller shaft 53a fixed to the roller support portion 51b via a roller bearing having a large number of rollers. In this embodiment, lubricating oil is supplied to a contact portion (cam / roller contact portion) P1 between the outer peripheral surface of the cam 111 and the outer peripheral surface of the roller 53 to improve the lubricity in the cam / roller contact portion P1. It is supposed to let you. As a structure for fixing the roller shaft 53a to the roller support portion 51b, for example, the roller shaft 53a is inserted into a roller shaft support hole 51d formed in the support plates 51e and 51e of the roller support portion 51b. Both end surfaces of the shaft 53a are crimped and plastically deformed to the outer peripheral side, and are assembled with the roller shaft support hole 51d being prevented from coming off and rotating.

  The lifter 51 is supported by a lifter guide 52 so as to be slidable along the axis (in the vertical direction in FIG. 3). That is, the lifter guide 52 has a substantially cylindrical space, and the lifter 51 is accommodated in the space so as to be slidable in the axial direction. The lifter guide 52 is formed in a cylindrical shape, for example, and is integrally attached to an upper portion of a cam carrier (not shown) that supports the intake camshaft 110.

  A retainer 26 is integrally attached to the proximal end portion of the plunger 23. A spring seat member 52 a is fitted on the upper portion of the lifter guide 52. A compression coil spring 27 is sandwiched between the lower surface of the spring seat member 52 a and the retainer 26. By the elastic force of the compression coil spring 27, an urging force in a direction of pushing down the plunger 23 (a direction in which the volume of the pressurizing chamber 22 is expanded) is applied and supported by the roller support portion 51b via the roller shaft 53a. The roller 53 is pressed toward the cam 111.

  Here, when the cam 111 rotates together with the intake camshaft 110, the cam nose 112 of the cam 111 applies an upward pressing force to the roller 53 and the lifter 51, so that the lifter 51 and the plunger 23 are raised while the compression coil The spring 27 is compressed to reduce the volume of the pressurizing chamber 22. On the other hand, when the cam 111 rotates to a position where the cam nose 112 is disengaged from the roller 53, the lifter 51 and the plunger 23 are lowered by the urging force of the compression coil spring 27, and the volume of the pressurizing chamber 22 is increased.

  The electromagnetic spill valve 30 is disposed to face the pressurizing chamber 22. The electromagnetic spill valve 30 includes an electromagnetic solenoid 31, a bobbin 32, a core 33, an armature 34, a poppet valve 35, and a seat body 36. The electromagnetic solenoid 31 includes a coil wound around the bobbin 32 in a ring shape, and a core 33 is fitted and fixed in the central through hole of the bobbin 32. A portion of the armature 34 is fixed to one end of the poppet valve 35, and a part of the armature 34 is disposed coaxially with the core 33 so as to enter the central through hole of the bobbin 32. Concave portions are formed on the opposing surfaces of the core 33 and the armature 34, and a compression coil spring 37 is housed in a compressed state between the concave portions. The armature 34 is urged toward the pressurizing chamber 22 by the elastic force of the compression coil spring 37. The poppet valve 35 is slidably inserted into a through hole in the sheet body 36. A disc-shaped valve body 35 a is formed at the lower end of the poppet valve 35.

  In the above configuration, when the electromagnetic solenoid 31 is not energized, the valve body 35a is separated from the seat portion 36a of the seat body 36 by the elastic force of the compression coil spring 37, and the electromagnetic spill valve 30 is opened. On the other hand, when the electromagnetic solenoid 31 is energized by supplying power to the terminal 38, a magnetic circuit is formed by the support member 39 that supports the core 33, the armature 34, and the electromagnetic spill valve 30 as a whole. On the contrary, the armature 34 moves to the core 33 side. As a result, the poppet valve 35 moves to the side opposite to the pressurizing chamber 22, the valve body 35a comes into contact with the seat portion 36a of the seat body 36, and the electromagnetic spill valve 30 is closed (shown in FIG. 3). Status).

  On the other hand, when the electromagnetic spill valve 30 is in the open state, fuel can flow between the plurality of supply passages 36 b formed in the seat body 36 and the pressurizing chamber 22.

  A low pressure fuel passage 11 is formed in the housing 10 so as to communicate with the supply passage 36b. When the plunger 23 descends with the electromagnetic spill valve 30 open, the low pressure fuel pumped from the fuel tank 101 by the operation of the feed pump 102 is filtered, the pressure regulator 142, the low pressure fuel passage 11, and The air is sucked into the pressurizing chamber 22 through the supply passage 36b.

  The pressurizing chamber 22 formed on the tip side of the cylinder 21 is formed with a larger diameter than the inner peripheral surface of the cylinder 21. The plunger 23 enters the pressurizing chamber 22 before the closing timing of the electromagnetic spill valve 30, and the plunger 23 reaches the top dead center after the electromagnetic spill valve 30 is closed. In addition, a gap is formed between the inner peripheral surface of the pressurizing chamber 22 and the outer peripheral surface of the plunger 23 in a state where the distal end portion of the plunger 23 has entered the pressurizing chamber 22. A high pressure fuel passage 12 is formed in the housing 10, and the pressurizing chamber 22 communicates with the check valve 40 through the high pressure fuel passage 12.

  The check valve 40 includes a casing 41 connected to the high-pressure fuel passage 12, a seat body 42 and a spring base body 45 disposed in the casing 41, and a valve body (valve) facing the seat body 42 so as to be able to contact and separate. Body) 43 and a compression coil spring 44 that urges the valve body 43 toward a contact position with respect to the seat body 42. The check valve 40 is connected to the high-pressure fuel pipe 105. When the pressure of fuel pumped from the pressurizing chamber 22 through the high pressure fuel passage 12 exceeds a predetermined value, the valve body 43 separates from the seat body 42 against the urging force of the compression coil spring 44. Moved to position. As a result, the check valve 40 is opened, and the high pressure fuel pumped from the high pressure fuel passage 12 is supplied to the delivery pipe 106 via the high pressure fuel pipe 105.

-Structure of roller lifter-
Next, a plurality of embodiments of the roller lifter structure, which is a characteristic part of this embodiment, will be described.

  As described above, the lifter 51 has both end surfaces of the roller shaft 53a in a state where the roller shaft 53a is inserted into the roller shaft support holes 51d and 51d respectively formed in the support plates 51e and 51e of the roller support portion 51b. The roller shaft 53a and the roller support portion 51b are integrally assembled by caulking the portion. Further, as described above, the roller shaft 53a rotatably supports the roller 53 via a roller bearing (needle bearing).

The feature of this embodiment is that the lifter main body 51a is configured to increase the swingable amount of the lifter 51 in the direction along the axis of the roller 53 (allowable amount of inclination in the lifter guide 52). In addition, there is provided a lifter tilt allowable amount adjusting means for limiting a swing allowable amount of the lifter 51 in a direction orthogonal to the axis of the roller 53. The following describes the implementation form of the lifter inclination tolerance adjustment hand stage.

( Embodiment )
FIG. 4 is a perspective view showing the lifter 51 in the present embodiment. 5 and 6 show a state in which the lifter 51 is tilted inside the lifter guide 52 due to the pressing force from the cam 111 during the pressurizing stroke, and FIG. 6 is a cross-sectional view as viewed from a direction perpendicular to the axis of the roller 53.

  As shown in these drawings, the lifter body 51a formed in a substantially cylindrical shape has inclined surfaces 54 and 55 formed by chamfering at the upper edge portion and the lower edge portion, respectively. As the shapes of the inclined surfaces 54 and 55, the inclined surfaces 54 and 55 are positioned at a position along the axial center of the roller 53 (phase position in the roller axis extending direction in the circumferential phase of the outer peripheral surface of the lifter body 51 a). In the direction perpendicular to the axial center of the roller 53 (the phase in the direction perpendicular to the roller axial extension direction in the circumferential phase of the outer peripheral surface of the lifter body 51a). The area of the inclined surfaces 54 and 55 gradually decreases toward the position (the chamfer dimension gradually decreases). Further, the inclined surfaces 54 and 55 are not formed at the phase position in the direction orthogonal to the roller axis extending direction in the circumferential phase of the outer circumferential surface of the lifter body 51a, and in this portion, the upper end surface and the lower surface of the lifter body 51a are not formed. The end surfaces are formed as flat surfaces 56 and 57 extending in the horizontal direction. Such shapes of the inclined surfaces 54 and 55 are obtained by changing the chamfering angle (inclination angle of the inclined surfaces 54 and 55) in accordance with the circumferential phase of the lifter body 51 a.

  In other words, the height dimension of the outer peripheral surface of the lifter main body 51a (the outer peripheral surface of the cylindrical portion) is minimum at the phase position in the roller axis extension direction in the circumferential phase of the outer peripheral surface of the lifter main body 51a. (Dimension T1 in FIG. 4) and the maximum in the phase position in the direction orthogonal to the roller axis extending direction in the circumferential phase of the outer circumferential surface of the lifter body 51a (dimension T2 in FIG. 4). The height dimension is gradually changed (from the phase position in the roller axis extension direction to the phase position in the direction perpendicular to the roller axis extension direction). . That is, the height dimension (fitting length dimension) of the contact surface with respect to the inner peripheral surface of the lifter guide 52 is minimized at the phase position in the roller axial direction in the circumferential direction of the outer peripheral surface of the lifter main body 51a. At the phase position in the direction orthogonal to the roller axis in the circumferential direction of the outer peripheral surface of 51a, the height dimension (fitting length dimension) of the contact surface with respect to the inner peripheral surface of the lifter guide 52 is maximized, It is formed so that the height dimension of the contact surface changes. Thereby, the lifter tilt allowable amount adjusting means referred to in the present invention is configured.

  Therefore, as shown in FIG. 5, the lifter with respect to the inner peripheral surface of the lifter guide 52 at the phase position in the direction orthogonal to the roller axis in the circumferential direction of the outer peripheral surface of the lifter main body 51 a (both lateral positions in FIG. 5). The inclination of the lifter 51 is largely restricted by the inner peripheral surface of the lifter guide 52 because the height dimension of the contact surface of the main body 51a is the maximum (dimension T2).

  On the other hand, the height dimension of the contact surface with respect to the inner peripheral surface of the lifter guide 52 is minimum (dimension T1) at the phase position in the roller axial direction in the circumferential direction of the outer peripheral surface of the lifter body 51a (both lateral positions in FIG. 6). For this reason, the restriction on the inclination of the lifter 51 by the inner peripheral surface of the lifter guide 52 is small, and the inclination of the lifter 51 is allowed to be large in this direction.

  For this reason, when the lifter 51 receives a load (component force) in a direction substantially perpendicular to the reciprocating direction from the cam 111 and the lifter 51 is inclined inside the lifter guide 52 by this load, In the left-right direction in FIG. 5 (phase position in the direction perpendicular to the roller axis in the circumferential direction of the outer peripheral surface of the lifter body 51 a), the inclination of the lifter 51 is largely restricted by the inner peripheral surface of the lifter guide 52. The sliding resistance at the contact portion when the upper end edge or the lower end edge of each of the two contacts the inner surface of the lifter guide 52 can be suppressed, and the above-described cocking of the lifter 51 can be suppressed.

  On the other hand, even in the case where the parallelism between the rotation axis of the cam 111 and the rotation axis of the roller 53 is not obtained, the roller in the left-right direction in FIG. Since the tilt of the lifter 51 is greatly allowed at the phase position in the axial direction), the lifter 51 can tilt following the tilt of the cam 111 and suppress the one-sided contact of the roller 53 with respect to the cam 111 described above. be able to. In other words, it is possible to suppress the contact of the roller 53 with respect to the cam 111 without requiring high accuracy in the processing accuracy and assembly accuracy of each component constituting the roller lifter and the processing accuracy and assembly accuracy of the cam 111. Therefore, the management of each accuracy can be relaxed.

  As described above, according to the present embodiment, the suppression of the cocking of the lifter 51 and the suppression of the contact of the roller 53 with the cam 111 can coexist, and the difference between the lifter 51 and the lifter guide 52 can be achieved. Generation of sound can be prevented, and sliding resistance between the two can be reduced, and smooth reciprocation of the lifter 51 can be realized. Further, it is possible to avoid the occurrence of damage such as pitching on the outer peripheral surface of the cam 111.

( Reference example )
Next, a reference example will be described. Present embodiment, the configuration of the lifter allowable slope amount adjusting means is different from that of the implementation described above. The other configuration is similar to that of implementation form, here mainly described structure and functions of the lifter allowable slope amount adjusting means.

FIG. 7 is a plan view of the lifter 51 in this reference example . The vertical direction in FIG. 7 is a direction along the axis of the roller 53, and the horizontal direction is a direction orthogonal to the axis of the roller 53. 8 and 9 show a state in which the lifter 51 is tilted inside the lifter guide 52 due to the pressing force from the cam 111 during the pressurizing stroke, and FIG. 9 is a cross-sectional view as viewed from the direction perpendicular to the axis of the roller 53. FIG.

As shown in these figures, the lifter body 51a according to the present embodiment, by the thickness dimension of the upper end portion is changed in the circumferential direction to form a re lid allowable slope amount adjusting means.

  Specifically, in a direction position orthogonal to the axis of the roller 53 (phase position in a direction orthogonal to the roller axis extension direction in the circumferential phase of the outer peripheral surface of the lifter main body 51a), the entire position is uniform. The plate thickness is set to be relatively large (dimension T3 in FIG. 7). On the other hand, at the position along the axis of the roller 53 (the phase position in the roller axis extension direction in the circumferential phase of the outer peripheral surface of the lifter body 51a), the plate thickness is gradually set smaller toward the upper end side. (The thickness dimension at the upper end position is indicated by dimension T4 in FIGS. 7 and 9). Further, as a change in the plate thickness dimension of the upper end portion of the lifter body 51a, as it goes toward the axial center position of the roller 53 (phase position in the roller axial extension direction in the circumferential phase of the outer peripheral surface of the lifter body 51a). The plate thickness dimension gradually decreases, and the plate thickness is minimum at the phase position in the roller axial direction in the circumferential direction of the outer peripheral surface of the lifter body 51a.

  As a result, the rigidity of the lifter body 51a is set to the minimum at the phase position in the roller axial direction in the circumferential direction of the lifter body 51a, while at the phase position in the direction perpendicular to the roller axis in the circumferential direction of the lifter body 51a. The rigidity of the lifter main body 51a is set to the maximum, and the rigidity gradually changes during that time (the rigidity gradually increases from the phase position in the roller axis direction to the phase position in the direction perpendicular to the roller axis). ) Is formed.

  For this reason, as shown in FIG. 8, since the rigidity is high at the phase position in the direction orthogonal to the roller axis in the circumferential direction of the outer peripheral surface of the lifter main body 51a (both side positions in the left-right direction in FIG. 8), the lifter The main body 51a is hardly deformed, and the inclination of the lifter 51 is largely restricted by the inner surface of the lifter guide 52, and the allowable amount of inclination of the lifter 51 relative to the lifter guide 52 in the direction perpendicular to the axis of the roller 53 is limited. Become.

  On the other hand, at the phase position in the roller axial direction in the circumferential direction of the outer peripheral surface of the lifter body 51a (both lateral positions in FIG. 9), since the rigidity is low, the lifter guide 52 is elastically deformed so that the lifter guide 52 is elastically deformed. The inclination with respect to increases.

  For this reason, when the lifter 51 receives a load (component force) in a direction substantially perpendicular to the reciprocating direction from the cam 111 and the lifter 51 is inclined inside the lifter guide 52 by this load, In the left-right direction in FIG. 8 (phase position in the direction orthogonal to the roller axis in the circumferential direction of the outer peripheral surface of the lifter main body 51 a), the inclination of the lifter 51 is largely restricted by the inner peripheral surface of the lifter guide 52. The sliding resistance at the contact portion when the upper end edge or the lower end edge of each of the two contacts the inner surface of the lifter guide 52 can be suppressed, and the above-described cocking of the lifter 51 can be suppressed.

  On the other hand, even in the case where the parallelism between the rotation axis of the cam 111 and the rotation axis of the roller 53 is not obtained well, the roller in the left-right direction in FIG. 9 (the circumferential direction of the outer peripheral surface of the lifter body 51a) (Phase position in the axial direction), the lifter 51 is inclined by the elastic deformation of the lifter body 51a, so that the lifter 51 can follow the inclination of the cam 111. It is possible to suppress the piece contact.

As described above, also in this reference example, the suppression of the cocking of the lifter 51, it is possible to coexist the suppression of partial contact of the roller 53 relative to the cam 111, abnormal noise between the lifter 51 and the lifter guide 52 The sliding resistance between the two can be reduced, and the smooth reciprocation of the lifter 51 can be realized. Further, it is possible to avoid the occurrence of damage such as pitching on the outer peripheral surface of the cam 111.

In this reference example , as shown in FIG. 7, the plate thickness is changed by making the inner surface of the lifter body 51 a an inclined surface, but as shown in FIG. 10 (a plan view of the lifter 51). The plate thickness may be changed by making the outer surface of the lifter body 51a an inclined surface.

  Further, as another means for setting the rigidity low, as shown in FIG. 11, a slit (notch portion) 58 may be provided in the lifter main body 51a. Specifically, a slit 58 is formed in the vicinity of the phase position in the roller axial direction in the circumferential direction of the lifter body 51a, and the rigidity at the phase position in the roller axial direction in the circumferential direction of the lifter body 51a is set low. Is. The effect obtained by setting the rigidity low in this way can be obtained in the same manner as described above.

-Other embodiments-
The embodiment of the present invention has been described above. However, the embodiment shown here is an example and can be variously modified.

Above you facilities embodiment, the lifter 51 has been configured to be reciprocated, the lifter 51 is reciprocated by rotation of a cam mounted on the exhaust camshaft by the rotation of the intake camshaft 110 cam 111 attached to the structure It is good.

Further, in the above you facilities embodiment, the lifter 51 by the cam 111 having three cam nose 112,112,112 is configured to be reciprocated by a cam having the other number cam nose (e.g., two cam noses) The lifter 51 may be configured to reciprocate.

Further, in the above you facilities embodiment, a case was described in which the present invention is applied to a cylinder direct injection six-cylinder gasoline engine mounted in an automobile. The present invention is not limited to this, and can be applied to, for example, a gasoline engine having any number of cylinders such as an in-cylinder direct injection four-cylinder gasoline engine. Further, the present invention is not limited to a gasoline engine, but can be applied to other internal combustion engines such as a diesel engine. Furthermore, the engine to which the present invention is applicable is not limited to an automobile engine.

Further, in the above you facilities embodiment describes a case of applying the present invention to the roller lifter of the high pressure fuel pump, the present invention is not limited thereto, it is applied to other equipment (eg valve train of the engine, etc.) It can also be applied to roller lifters.

It is a figure which shows typically the fuel supply apparatus which concerns on embodiment. It is a figure for demonstrating the opening / closing operation | movement of an electromagnetic spill valve. It is a longitudinal cross-sectional view which shows a high pressure fuel pump. It is a perspective view showing a lifter of implementation embodiment. Lifter is a diagram viewed in a direction along the axis of the roller a state in which the inclined inside of the lifter guide in the implementation form. Lifter in implementation form is a sectional view seen from a direction perpendicular to the axis of the roller a state in which the inclined inside of the lifter guide. It is a top view of the lifter in a reference example . It is the figure which looked at the state where the lifter inclines inside the lifter guide in the reference example from the direction along the axial center of the roller. It is sectional drawing which looked at the state where the lifter inclines inside the lifter guide in the reference example from the direction orthogonal to the axial center of a roller. It is a top view of the lifter in the 1st modification of a reference example . It is a top view of the lifter in the 2nd modification of a reference example . It is the figure which looked at the state where the lifter inclines inside the lifter guide in the prior art example from the direction along the axial center of the roller. It is sectional drawing which looked at the state which the lifter inclined in the inside of the lifter guide in the prior art example from the direction orthogonal to the axial center of a roller.

Explanation of symbols

1 High Pressure Fuel Pump 51 Lifter 51a Lifter Main Body 52 Lifter Guide 53 Rollers 54, 55 Inclined Surface 58 Slit 111 Cam

Claims (3)

In a roller lifter structure including a roller that contacts the outer peripheral surface of the cam and receives a pressing force from the cam, and a lifter that rotatably supports the roller and is reciprocally accommodated in the internal space of the lifter guide.
The lifter includes a lifter body formed in a substantially cylindrical shape,
At the phase position in the roller axial extension direction in the circumferential phase of the outer peripheral surface of the lifter body, the fitting length dimension in the reciprocating direction of the portion contacting the inner surface of the lifter guide is set to be short. In addition to increasing the allowable tilt of the lifter relative to the lifter guide in the axial extension direction, the phase position in the direction perpendicular to the roller axial extension direction in the circumferential phase of the outer peripheral surface of the lifter body is on the inner surface of the lifter guide. Lifter tilt tolerance adjustment means for restricting the lifter tilt tolerance with respect to the lifter guide in the direction perpendicular to the roller axis extending direction, with the fitting length dimension in the reciprocating direction of the contact portion being set long. A roller lifter structure characterized by comprising: In the roller lifter structure according to claim 1,
The lifter tilt allowable amount adjusting means is configured such that the fitting length extends from the phase position in the roller axis extending direction in the circumferential phase of the outer circumferential surface of the lifter body to the roller axis extension in the circumferential phase of the outer circumferential surface of the lifter body. A roller lifter structure characterized by being set to be gradually longer toward a phase position in a direction orthogonal to the direction. In the roller lifter structure according to claim 1 or 2,
The lifter tilt allowable amount adjusting means is configured by chamfering the outer peripheral edge portions at both ends in the axial direction of the lifter body, and in the roller axis extension direction in the circumferential phase of the outer peripheral surface of the lifter body. The chamfer dimension is set to be large at the phase position, while the chamfer dimension is set to be small at the phase position in the direction orthogonal to the roller axis extending direction in the circumferential phase of the outer peripheral surface of the lifter body. Roller lifter structure.

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