JP2013142364A - Drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive device that can, even when something abnormal happens on a driven member side, suppress a damage of peripheral components of a rocker arm, and can even improve an assembling property and durability.SOLUTION: The device includes a drive cam 21, a rocker arm 22 that sways in response to the rotation of the drive cam, and a rocker arm supporting mechanism 23 for swayably supporting the rocker arm 22 in cooperation with the drive cam 21. The drive device reciprocates, according to the swaying of the rocker arm 22, a plunger 12 biasing a swaying end part 22a of the rocker arm 22 to the drive cam 21 side. The rocker arm supporting mechanism 23 includes a pivot member 25 swayably supporting a base end part 22b of the rocker arm 22 at a first supporting position in a reciprocating direction of the plunger 12, a pump attaching case 24 displaceably supporting the pivot member 25 from the first supporting position to the drive cam 21 side, and a compression coil spring 27 biasing the pivot member 25 from the first supporting position to the drive cam 21 side.

Description

  The present invention relates to a drive device that reciprocates a driven member by a rocker arm, and more particularly to a drive device suitable for driving a high-pressure fuel pump that pressurizes fuel of an internal combustion engine to a high pressure capable of in-cylinder injection.

  A drive device provided with a rocker arm can reciprocate a driven member engaged with the rocker arm by swinging the rocker arm in accordance with a rotation input. Such a drive device is widely used in a valve mechanism of an internal combustion engine, but is also applied to another device, for example, a drive device of a high-pressure fuel pump that pressurizes the fuel of the internal combustion engine to a high pressure by reciprocating a plunger. it can.

  As a conventional drive device provided with a rocker arm, for example, in order to prevent the rocker arm from falling off when assembling a head cover provided with a bearing portion of a camshaft, it is close to the rocker arm's rocking fulcrum. For example, a rocker arm supporting portion that restricts the rocker arm from falling off is provided integrally with the head cover (see, for example, Patent Document 1).

  In addition, the cam follower is supported by a support shaft penetrating in the direction of the central axis of the cam follower so that the cam follower can be prevented from falling off the plunger even when the plunger for driving the unit injector is stuck, and the lifting direction by the tension spring There is also known one that is biased to (see, for example, Patent Document 2).

  Further, there is also known one in which a rocking fulcrum portion of a cam follower with a roller is supported by a support shaft penetrating in the rocking central axis direction, and a regulating member for regulating a movable range of the cam follower is provided (for example, Patent Documents). 3).

JP 2007-192101 A Japanese Utility Model Publication No. 05-21163 JP 2004-308615 A

  However, in the conventional driving device in which the rocker arm support portion that is close to the rocking fulcrum portion of the rocker arm with a small gap is provided, the rocker arm can be prevented from falling off, but is driven by the rocker arm. When the push rod, the valve stem, or the like raises a stick, the rocker arm is not normally supported, and there is a concern that the peripheral parts may be damaged by hitting from the drive cam.

  In particular, when such a drive device is used to drive a fuel pump that reciprocates the plunger vertically above the rocker arm, the rocker that is no longer supported normally when the plunger causes a sliding abnormality such as a stick. It is considered that there is a high possibility that the arm may be damaged by hitting from the drive cam or the like, or the peripheral parts may be damaged.

  Further, in the conventional drive device that supports the swing fulcrum portion of the cam follower on the support shaft that penetrates in the direction of the swing center axis, it is not only easy to assemble because it is necessary to pass the support shaft through the cam follower. There was a problem that the contact pressure of the roller became non-uniform and the durability deteriorated.

  Therefore, the present invention can suppress damage to the parts around the rocker arm even if some abnormality occurs on the driven member side, and can further improve the assembling property and durability of the driven member. Is to provide.

  In order to solve the above problems, the fuel pump according to the present invention includes (1) a drive cam, a rocker arm that engages with the drive cam at an intermediate portion in the longitudinal direction, and rocks according to the rotation of the drive cam; A rocker arm support mechanism that supports the rocker arm in a swingable manner in cooperation with the drive cam, and a driven member that urges the rocking end of the rocker arm in a direction approaching the drive cam The rocker arm support mechanism is configured to reciprocate the rocker arm according to the rocking movement of the rocker arm. A pivot member that slidably supports an end portion, a support member that movably supports the pivot member from the first support position in the reciprocating direction toward the drive cam, and the pivot Characterized in that the door member from the first supporting position is configured to include a, a biasing mechanism for biasing the drive cam side.

  In this invention, the rocker arm that engages with the drive cam biases the pivot member toward the support member by the biasing force applied to the drive cam side from the driven member to the rocking end of the rocker arm. The pivot member is biased by a biasing mechanism that biases the pivot member from the first support position toward the drive cam. Therefore, when some abnormality occurs on the driven member side and the urging force from the driven member side to the rocker arm decreases, the pivot member is displaced from the first support position to the driving cam side by the urging force from the urging mechanism. At the same time, the rocker arm that engages with the drive cam displaces its swing end toward the driven member, and the rocker arm is supported at three points. As a result, even if some abnormality occurs on the driven member side, it is possible to avoid damage to the peripheral parts due to the rocking of the rocker arm by avoiding the impact of the rocker arm by the driving cam. When the urging force from the driven member side that urges the rocker arm toward the drive cam is normally applied to the rocker arm, the rocker arm is moved by the pivot member of the rocker arm support mechanism, the driven member, and the drive cam. While being supported at three points, it swings according to the rotation of the drive cam.

  In the drive device of the present invention, it is preferable that (2) the intermediate portion of the rocker arm is in a state where the rocking end portion of the rocker arm is urged toward the drive cam by an urging force within a certain range. When engaging with the drive cam, the pivot member is positioned at the first support position against the biasing force of the biasing mechanism.

  In this case, the normal rocking fulcrum position of the rocker arm can be stabilized, and when the urging force from the driven member side is impaired, the base end of the rocker arm is quickly and accurately adjusted by a necessary amount. It can be displaced toward the drive cam.

  In the drive device having the configuration of (2) above, (3) the biasing force by which the driven member biases the rocking end of the rocker arm toward the drive cam is deviated from the predetermined range. Then, the pivot member is displaced from the first support position to the drive cam side by the urging force of the urging mechanism, and the swinging end portion of the rocker arm is displaced to the driven member side. It is more preferable.

  This configuration stabilizes the normal swing fulcrum position of the rocker arm, and only when the urging force from the driven member side falls outside the normal fluctuation range, and quickly and accurately only the required amount. The base end of the arm can be displaced toward the drive cam.

  In the drive device having the configuration of (3), (4) the pivot member is displaced from the first support position to the drive cam side by the urging force of the urging mechanism and reaches the second support position. It is preferable that a drop-off preventing member that engages with the base end portion of the rocker arm and restricts the displacement of the base end portion toward the drive cam is provided.

  With this configuration, it is possible to improve the assembling performance by exhibiting the rocker arm positioning function when assembling the driven member, and to improve the durability by reducing the friction at the rocking fulcrum portion of the rocker arm. You can also.

  In the drive device having the configuration of (4), it is preferable that (5) the drop-off prevention member is supported by the support member.

  In this case, the amount of displacement of the base end portion of the rocker arm and the pivot member toward the drive cam is within a certain range from before the drive device is assembled to the internal combustion engine side or before the driven member and the rocker arm are engaged. It is possible to regulate the inside, and the assembly work can be facilitated.

  In the driving device according to the present invention, (6) the rocker arm includes a roller that is movably engaged with the driving cam between the base end portion and the swing end portion. desirable.

  In this case, not only rocking of the rocker arm according to the rotation of the drive cam but also rocking of the rocker arm when the pivot member is displaced (switching of the end serving as the rocking fulcrum) and the rocker arm during the rocking The engagement position (roller contact position) of the drive cam can be easily moved.

  In the driving device of the present invention, (7) the driven member is constituted by the input member of the pump device that sucks and discharges fluid into the pump body by reciprocating movement of the input member, It is preferable to have an elastic member that biases the input member toward the side approaching the drive cam.

  In this case, the input member of the pump device can be reciprocated according to the rocker arm swinging according to the rotation of the drive cam, and the drive device is suitable for a high-pressure pump. Also, when the input member of the pump device cannot normally reciprocate due to some abnormality and the urging force from the input member that urges the rocker arm toward the drive cam is greatly reduced or lost, the drive of the pivot member The rocking fulcrum of the rocker arm can be switched to the normal oscillating end side by the displacement toward the cam. Therefore, even when the urging force from the input member is greatly impaired, the pivot member is supported at three points by the rocker arm support mechanism and the drive cam, and the rocker arm is not struck by the drive cam and the rocker arm Damage to peripheral parts due to flapping can be suppressed. In addition, the assembling property of the pump device can be improved by exhibiting the rocker arm positioning function on the drive device side when the pump device is assembled.

  The pivot member referred to in the present invention holds the base end portion of the rocker arm so as to be slidable not only in the rocking direction of the rocker arm but also in an inclined direction perpendicular thereto.

  According to the present invention, when some abnormality occurs on the driven member side and the urging force from the driven member side to the rocker arm decreases, the pivot member is driven from the first support position by the urging force from the urging mechanism. Since the cam member is displaced toward the cam side, the rocker arm can be supported at three points even when the urging force from the input member is greatly impaired. As a result, even if some abnormality occurs on the driven member side, it is possible to avoid damage to the peripheral parts due to the rocking of the rocker arm by avoiding the hitting of the rocker arm by the driving cam, and when the driven member is assembled. It is possible to provide a drive device capable of improving the assemblability and durability.

It is explanatory drawing of schematic structure of the drive device of the fuel pump which concerns on one Embodiment of this invention. It is sectional drawing of the fuel pump which concerns on one Embodiment of this invention, and its drive device. It is a principal part expanded sectional view which shows the state in which the plunger in the drive device of the fuel pump which concerns on one Embodiment of this invention exists in the bottom dead center vicinity. FIG. 3 is an enlarged cross-sectional view of a main part showing a state in which a plunger in a fuel pump drive device according to an embodiment of the present invention causes a stick near top dead center and a rocker arm swings downward to near a normal bottom dead center position. is there. FIG. 6 shows a state in which the rocker arm swing fulcrum position is switched by the displacement of the pivot member toward the drive cam after the plunger in the fuel pump drive device according to the embodiment of the present invention causes a stick near top dead center. It is a principal part expanded sectional view.

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

(One embodiment)
FIG. 1 to FIG. 5 are diagrams showing a driving apparatus according to an embodiment of the present invention, and show an example in which the present invention is applied to a driving apparatus for a plunger pump type high-pressure fuel pump.

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

  As shown schematically in FIG. 1, the fuel pump 10 of the present embodiment is connected to a feed pump FP provided in the fuel tank T via a pipe L, and the feed pump FP is connected to the fuel pump 10. A fuel pressurized to a relatively low feed pressure is introduced. The feed pump FP is, for example, an electric low-pressure fuel pump, and pumps up gasoline that is fuel in the fuel tank T.

  In the present embodiment shown in FIGS. 1 to 5, the fuel pump 10 is driven by a drive device 20.

  The fuel pump 10 includes a pump body 11, a plunger 12 attached to the pump body 11 so as to be capable of reciprocating in the axial direction, and an end portion 12 a (upper end portion in FIG. 1) between the plunger 12 and the pump body 11. And a pressurizing chamber 13 defined.

  In addition, the pump body 11 has a suction passage 11a (fuel passage) for introducing fuel from the feed pump FP into the pressurizing chamber 13, and fuel pressurized inside the pressurizing chamber 13 is discharged to the delivery pipe side. A discharge passage 11b (fuel passage) is formed.

  The drive device 20 includes a drive cam 21, a rocker arm 22 that swings according to the rotation of the drive cam 21, and a rocker arm support mechanism 23 that supports the rocker arm 22 in a swingable manner in cooperation with the drive cam 21. It has. The rocker arm support mechanism 23 has a pump mounting case 24 (support member) that is integrally attached to a part of the outer wall portion of the engine.

  The plunger 12 of the fuel pump 10 is an input member that urges the rocker arm 22 in a direction approaching the drive cam 21 on the other end 12 b side. The drive device 20 swings the plunger 12 on the rocker arm 22. It can reciprocate in the axial direction corresponding to the moving direction.

  Specifically, as shown in FIG. 2, the pump body 11 of the fuel pump 10 includes a plurality of flange portions 11 f each having bolt holes 11 c (only one is shown in FIG. 2), and a pump of the pump mounting case 24. It has a fitting portion 11g fitted into the mounting hole 24a, and is fastened to the pump mounting case 24 by a plurality of bolts (not shown) inserted into the plurality of bolt holes 11c. The pump body 11 has a fuel introduction pipe part 11i and a fuel discharge pipe part 11j, and a fuel filter 17 is provided inside the fuel introduction pipe part 11i.

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

  The plunger 12 is a driven member that is driven by the drive cam 21 via the rocker arm 22 from the other end 12b side.

  The drive cam 21 is provided in a cylinder head (not shown in detail) constituting the pump mounting case 24, and is driven by rotational power from the engine. The drive cam 21 is integrally mounted on, for example, an exhaust camshaft (not shown in detail) of the engine.

  A spring receiving portion 12c is mounted in the vicinity of the other end portion 12b of the plunger 12, and a compression coil spring 19 (elastic member) is incorporated in a compressed state between the spring receiving portion 12c and the pump body 11. It is. The compression coil spring 19 is an elastic member that urges the plunger 12 toward the side approaching the drive cam 21, and the plunger 12 increases the volume of the pressurizing chamber 13 by the compression coil spring 19 (FIG. 2). It is always energized in the downward direction. Therefore, when the drive cam 21 is rotationally driven by the power from the engine, the plunger 12 reciprocates in the axial direction according to the reciprocal swing of the rocker arm 22 according to the rotation of the drive cam 21.

  The rocker arm 22 includes a swing end 22a that engages with the other end 12b of the plunger 12, a base end 22b supported on the pump mounting case 24 side, and the swing end 22a and the base end 22b. And an intermediate portion 22c that rotatably holds a roller 22r that is rotatably engaged with the drive cam 21. The rocker arm 22 is lubricated together with the other end portion 12b of the plunger 12 by engine oil in the cylinder head (oil from the outside).

  Before and after the pressurization chamber 13, that is, on the suction side and the discharge side of the pressurization chamber 13, the fuel intake into the pressurization chamber 13 is allowed on the downstream side of the fuel filter 17, and the check that exhibits the backflow prevention function is exhibited. A suction valve 14 made of a valve and a discharge valve 16 made of a check valve that allows the fuel to be discharged from the pressurizing chamber 13 and that exhibits a backflow prevention function are provided.

  The suction valve 14 has a plate-like valve body 14a and an annular valve seat 14b for opening and closing the suction passage 11a, and a valve until a predetermined suction pressure (pressure lower than the feed pressure by a predetermined suction valve opening differential pressure) is reached. It is comprised by the valve spring 14c which hold | maintains the valve closing state which makes the body 14a contact | abut to the valve seat 14b.

  The discharge valve 16 includes a plate-like valve body 16a that opens and closes the discharge passage 11b and an annular valve seat 16b, and a predetermined discharge pressure (a pressure that is higher than the pressure of fuel in the delivery pipe by a predetermined discharge valve opening differential pressure). ) Until the valve body 16a comes into contact with the valve seat 16b.

  Therefore, when the plunger 12 is displaced upward in FIG. 1 so as to decrease the volume of the pressurizing chamber 13, the fuel in the pressurizing chamber 13 is pressurized under the closed state of the intake valve 14 to increase its pressure. The fuel can be discharged from the pressurizing chamber 13 while the discharge valve 16 is opened. Further, when the plunger 12 is displaced downward in FIG. 1 so as to increase the volume of the pressurizing chamber 13, the fuel in the pressurizing chamber 13 is depressurized and the pressure is lowered, and the discharge valve 16 is closed. The suction valve 14 can be opened below.

  The intake valve 14 is provided with an electromagnetic operation mechanism 15.

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

  The electromagnetic operation mechanism 15 can suck the operation member 15a toward the electromagnetic coil portion 15c when the electromagnetic coil portion 15c is excited by energization (when in an ON state), and the valve body 14a of the intake valve 14 is a valve spring. It can be returned to the valve closing direction by the urging force of 14c. Further, the electromagnetic operating mechanism 15 forces the intake valve 14 against the urging force of the valve spring 14c by the valve opening operating spring 15b when the energization of the electromagnetic coil portion 15c is stopped and becomes a non-excited state (OFF state). The valve can be opened automatically. Therefore, the electromagnetic operation mechanism 15 controls the period during which the intake valve 14 is forcibly opened by energization of the electromagnetic coil portion 15c, so that the pressurization period (discharge period) of the fuel in the pressurization chamber 13 by the plunger 12 is controlled. ) Can be variably controlled.

  On the other hand, the rocker arm support mechanism 23 includes a pivot member 25, a drop-off prevention member 26, and a compression coil spring 27 in addition to the pump mounting case 24.

  The pivot member 25 includes a hollow base end side shaft portion 25a supported by the pump mounting case 24, a substantially spherical or hemispherical pivot portion 25b that supports the base end portion 22b of the rocker arm 22 in a swingable manner, An annular flange portion 25c that abuts against the pump mounting case 24 at a first support position in the axial direction of the plunger 12 (the position shown in FIG. 2).

  The pivot member 25 can swingably support the base end portion 22b of the rocker arm 22 at the first support position when being pushed upward from the base end portion 22b of the rocker arm 22 in the drawing. It is like that. Further, the pivot portion 25b of the pivot member 25 holds the base end portion 22b on the rocking fulcrum side of the rocker arm 22 so as to be tiltable and changeable in any direction including the rocking direction of the rocker arm 22. The center of the pivot portion 25b is a swing fulcrum (swing center) of the rocker arm 22. The pivot member 25 is formed with a lubricating oil hole 25h through which oil passes, and the base end 22b of the rocker arm 22 has an oil hole 22h that guides the oil from the lubricating oil hole 25h to the vicinity of the outer peripheral surface of the roller 22r. And a concave spherical surface portion (no symbol) corresponding to the pivot portion 25b of the pivot member 25 is formed.

  The pump mounting case 24 is formed with a pivot holding hole 24c and an oil supply hole 24d for slidably fitting the proximal end side shaft part 25a of the pivot member 25. The pump holding case 24 has an inside of the pivot holding hole 24c. The oil supplied at a predetermined lubricating oil pressure is supplied to the engaging portion of the roller 22r and the drive cam 21 through the lubricating oil hole 25h of the pivot member 25 and the oil hole 22h of the rocker arm 22.

  The pump mounting case 24 is configured to position and hold the pivot member 25 at the first support position when the flange portion 25c of the pivot member 25 abuts from the lower surface side in FIG. The pump mounting case 24 supports the pivot member 25 so as to be displaceable from the first support position to the drive cam 21 side by slidably holding the proximal end side shaft portion 25a of the pivot member 25.

  Normally, the rocker arm 22 engages the roller 22r in the middle portion in the longitudinal direction with the drive cam 21 and also exerts a downward biasing force (hereinafter referred to as “downward”) from the compression coil spring 19 via the plunger 12 on the swing end portion 22a side. , Also referred to as a first urging force), and urged counterclockwise in FIG. Then, the base end portion 22b of the rocker arm 22 pushes the pivot member 25 upward in the drawing to position the pivot member 25 at the first support position.

  The drop-off prevention member 26 is fixed to the pump mounting case 24, and extends from the pump mounting case 24 toward the lower side in the drawing, and from the lower end portion of the fixed end side portion 26a in the drawing. And a free end portion 26b bent toward the base end 22b side of the rocker arm 22. The free end side portion 26 b of the dropout prevention member 26 is located closer to the drive cam 21 than the base end portion 22 b of the rocker arm 22 in the axial direction that is the reciprocating direction of the plunger 12. The drop-off prevention member 26 cooperates with the compression coil spring 27 to prevent the base end portion 22b of the rocker arm 22 from dropping from the drive cam 21 side.

  The compression coil spring 27 is a biasing mechanism that biases the pivot member 25 from the first support position toward the drive cam 21 (downward in FIG. 2, the clockwise direction of the rocker arm 22). The compression coil spring 27 is configured so that the pivot member 25, which is normally pushed into the first support position, moves from the first support position to the drive cam 21 when the urging force from the compression coil spring 19 side via the plunger 12 decreases. To escape to the side.

  The compression coil spring 27 is housed in a pivot holding hole 24c formed in the pump mounting case 24, and is usually compressed between the pump mounting case 24 and the proximal end side shaft portion 25a of the pivot member 25. Held in a state.

  Specifically, a downward biasing force (hereinafter also referred to as a second biasing force) applied to the pivot member 25 by the compression coil spring 27 and a radius from the center of the roller 22r to the point of application of the second biasing force. 2 acts on the rocker arm 22 in response to the first biasing force and the roller applied to the rocking end 22a of the rocker arm 22 from the compression coil spring 19 via the plunger 12. This is sufficiently smaller than the counterclockwise rotational moment acting on the rocker arm 22 according to the radius from the center of 22r to the point of application of the first urging force. Therefore, when the first urging force from the compression coil spring 19 is normally applied to the rocking end 22a of the rocker arm 22 via the plunger 12 with respect to the rocker arm 22 engaged with the drive cam 21, the rocker The base end portion 22b of the arm 22 pushes the pivot member 25 upward in the drawing against the second biasing force from the compression coil spring 27, and the pivot member 25 is positioned at the first support position.

  That is, when the rocking end 22a of the rocker arm 22 is urged toward the drive cam 21 by the first urging force within a certain range, the roller 22r of the rocker arm 22 is engaged with the drive cam. The member 25 is positioned at the first support position against the urging force of the compression coil spring 27.

  On the other hand, the normal sliding state between the plunger 12 and the pump body 11 is damaged by some abnormality, and the plunger 12 is forcibly moved to the top dead center by the drive cam 21, but from the compression coil spring 19. If the urging force cannot be lowered smoothly, the first urging force for urging the rocker arm 22 toward the drive cam 21 is deviated from within a certain range and is significantly reduced. In such a case, the pivot member 25 is displaced from the first support position toward the drive cam 21 by the urging force of the compression coil spring 27, and the rocker arm 22 is swung clockwise in FIG. The rocking end 22a of the rocker arm 22 is attached to the other end 12b of the plunger 12 that cannot stop following the rotation of the drive cam 21 while stopping at the upper side or repeating the stick (temporary catching stop). It can come into contact. In other words, the pivot member 25 supports the rocker arm 22 at three points by the plunger 12, the drive cam 21 and the pivot member 25 (held in a fixed position in both the reciprocating motion direction of the plunger 12 and the rocking direction of the rocker arm 22). In order to prevent the state to be lost from being damaged by the delay or stop of the sliding of the plunger 12, the biasing force of the compression coil spring 27 can be displaced from the first support position to the drive cam 21 side. Yes.

  Further, the drop-off prevention member 26 is displaced from the first support position (stop position in FIG. 2) to the drive cam side by the pivot member 25 by the urging force of the compression coil spring 27 and moved to the second support position (in FIG. 5). When it reaches the stop position), the base end 22b of the rocker arm 22 is engaged, and the displacement of the base end 22b toward the drive cam 21 can be regulated. It has become.

  More specifically, the pump body 11 is constituted by a plurality of cylindrical or annular segments (no reference numerals) that are adjacent in the axial direction and are fluid-tightly fitted to each other via a seal ring such as an O-ring. Has been.

  An oil seal holding portion 18 that holds a plurality of seal rings 41 and 42 that engage with the plunger 12 is provided on the lower end side of the pump body 11 exposed in the pump mounting case 24 in the drawing. Here, the seal ring 41 is a fuel seal that suppresses fuel leakage by sealing the sliding gap portion between the plunger 12 and the pump body 11. The seal ring 42 allows the engine oil in the cylinder head to be connected to the plunger 12. An oil seal that suppresses entry into the sliding gap portion of the pump body 11 is provided.

  Next, the operation will be described.

  In the drive device 20 of the fuel pump 10 of the present embodiment configured as described above, the drive cam 21 rotates in the rotation direction indicated by the white arrow in FIG. 2 during the operation of the engine. Then, the first urging force from the compression coil spring 19 that urges the rocking end 22 a of the rocker arm 22 toward the drive cam 21 is normally applied to the rocking end 22 a of the rocker arm 22 via the plunger 12. Join.

  During such a normal operation, as shown in FIG. 2, the rocker arm 22 is moved by the pivot member 25, the plunger 12, and the drive cam 21 with the pivot member 25 positioned at the first support position. While being supported at three points, it reciprocates according to the rotation of the drive cam 21. The plunger 12 has a top dead center position where the lift amount by the drive cam 21 is maximum as shown in FIG. 2 and a bottom dead center position where the lift amount by the drive cam 21 is minimum as shown in FIG. Reciprocate in the axial direction. Then, under the state in which the volume of the pressurizing chamber 13 is changed with the reciprocating motion of the plunger 12, the electromagnetic operation mechanism 15 controls the period during which the suction valve 14 is forcibly opened. The fuel pressurization period in the pressurization chamber 13 is variably controlled, and the fuel discharge amount of the fuel pump 10 is controlled.

  In such a state, since the pivot member 25 is positioned at the first support position against the biasing force of the compression coil spring 27, the normal swing fulcrum position of the rocker arm 22 can be stabilized. .

  Now, suppose that the normal sliding state between the plunger 12 and the pump body 11 is damaged by some abnormality. For example, it is assumed that the plunger 12 is baked on the pump body 11 side, or a foreign object enters between the plunger 12 and the pump body 11 to impair the slidability of the plunger 12.

  At this time, the plunger 12 is forcibly moved to the top dead center by the drive cam 21, but cannot be lowered smoothly by the first urging force from the compression coil spring 19, and as shown in FIG. There is a possibility that it will not be possible to follow the rotation of the drive cam 21 while stopping at the upper side in FIG.

  However, in such a case, as shown in FIG. 5, the pivot member 25 is engaged with the drive cam 21 by being displaced from the first support position toward the drive cam 21 by the urging force from the compression coil spring 27. The rocker arm 22 displaces the oscillating end 22a toward the other end 12b of the plunger 12 and makes it come into contact therewith.

  At this time, the rocking fulcrum of the rocker arm 22 can be switched from the pivot member 25 side to the other end portion 12b side of the plunger 12, but the three-point support state of the rocker arm 22 is immediately recovered.

  Therefore, even if some abnormality occurs on the plunger 12 side, the rocking of the rocker arm 22 by the drive cam 21 can be avoided and damage to peripheral components due to the rocking of the rocker arm 22 can be suppressed.

  In the present embodiment, the pivot member 25 is compressed when the first urging force that the plunger 12 urges the swinging end portion 22a of the rocker arm 22 toward the drive cam 21 falls and falls within a certain range. The biasing force of the coil spring 27 is displaced from the first support position toward the drive cam 21 to displace the rocking end 22a of the rocker arm 22 toward the plunger 12 side. Therefore, with respect to the plunger 12 that can no longer follow the rotation of the drive cam 21, the base end portion 22b of the rocker arm 22 is displaced to the drive cam 21 side by a necessary amount quickly and accurately, and the rocker arm 22 is supported at three points. The state can be recovered immediately.

  Further, in the present embodiment, when the pivot member 25 is displaced from the first support position to the drive cam 21 side by the urging force of the compression coil spring 27 and reaches the second support position, the drop-off prevention member 26 becomes the rocker arm. 22 is engaged with the base end portion 22b, and the base end portion is restricted from dropping and displacing toward the drive cam 21 side. Therefore, by exhibiting the positioning function of the rocker arm 22 when the plunger 12 is assembled, the assemblability can be improved. By using the pivot member 25, the friction at the swing fulcrum portion of the rocker arm 22 can be improved. The durability can also be improved by reducing or making the back work of the roller 22r and the drive cam 21 uniform.

  In addition, in the present embodiment, since the drop-off prevention member 26 is supported by the pump mounting case 24, the displacement amount of the rocker arm 22 toward the drive cam 21 side of the base end portion 22b of the rocker arm 22 and the pivot member 25 is determined. It can be regulated within a certain range before assembly to the internal combustion engine side or before engagement of the plunger 12 and the rocker arm 22, and the assembling work can be facilitated.

  Further, in the drive device 20 of the present embodiment, the rocker arm 22 has a roller 22r that engages with the drive cam 21 in a rollable manner between the base end portion 22b and the swing end portion 22a. Therefore, not only the rocking of the rocker arm 22 according to the rotation of the drive cam 21, but also the switching of the rocking fulcrum of the rocker arm 22 when the pivot member 25 is displaced, and the roller contact position of the rocker arm 22 during the switching. The movement is easily possible, and the stable posture of the rocker arm 22 is easily secured.

  Furthermore, since the plunger 12 can be reciprocated according to the rocker arm 22 swinging according to the rotation of the drive cam 21, the drive device 20 suitable for a high-pressure pump is obtained. In addition, when the fuel pump 10 is assembled, the assembly function of the fuel pump 10 can be improved by exerting the positioning function of the rocker arm 22 on the drive device 20 side.

  As described above, in this embodiment, when some abnormality occurs on the plunger 12 side and the urging force from the plunger 12 side to the rocker arm 22 falls outside a certain range, the pivot member 25 is moved away from the compression coil spring 27. Since the urging force is displaced from the first support position to the drive cam 21 side, the three-point support state of the rocker arm 22 can be ensured even when the urging force from the plunger 12 is greatly impaired. . As a result, even if any abnormality occurs on the plunger 12 side, it is possible to prevent damage to peripheral components due to flapping of the rocker arm 22 by avoiding the impact of the rocker arm 22 by the drive cam 21, and the assembly of the fuel pump 10. It is possible to provide the driving device 20 that can improve the attachment and durability.

  In the above-described embodiment, the pivot member 25, the rocker arm 22, and the drop-off prevention member 26 are arranged linearly in the longitudinal direction of the rocker arm 22. The arrangement | positioning form which remove | deviates from the axis line of the longitudinal direction of the rocker arm 22 can be taken.

  In the above-described embodiment, the driving device 20 drives the high-pressure pressurizing fuel pump 10, but the driving device of the present invention is also suitable for driving a plunger type pump other than the fuel pump. The present invention can also be applied to driving other devices having an input member that reciprocates according to the rocker arm swinging.

  Furthermore, in the above-described embodiment, the compression coil spring 27 is used as the biasing mechanism. However, other spring elements may be used, and the pivot member 25 is attached to the drive cam side by using a spring and a lever together. Other biasing mechanisms that can be biased may be used.

  In addition, the rocker arms are all roller rocker arms, but the contact pressure between the concave spherical surface of the base end portion 22b of the rocker arm 22 and the pivot portion 25b and the side pressure acting on the pivot member 25 are the case of the rocker arm with rollers. Other inclusions may be interposed between the rocker arm and the drive cam as long as the configuration can be reduced to the same extent.

  As described above, in the drive device according to the present invention, when some abnormality occurs on the driven member side and the urging force from the driven member side to the rocker arm decreases, the urging force from the urging mechanism is applied to the pivot member. Accordingly, the rocker arm can be supported at three points even when the urging force from the input member is greatly impaired. Therefore, even if some abnormality occurs on the driven member side, it is possible to avoid damage to the peripheral parts due to the rocking of the rocker arm by avoiding the hitting of the rocker arm by the driving cam, and at the time of assembling the driven member. It is possible to provide a drive device that can improve the attachment and durability. The present invention as described above is a general drive device that reciprocates a driven member by a rocker arm, and in particular, a general drive device that is suitable for driving a high-pressure fuel pump that pressurizes fuel of an internal combustion engine to a high pressure capable of in-cylinder injection. Useful for.

DESCRIPTION OF SYMBOLS 10 Fuel pump 11 Pump body 11a Suction passage 11b Discharge passage 12 Plunger 12a One end part 12b Other end part 12c Spring receiving part 13 Pressurization chamber 14 Suction valve 15 Electromagnetic operation mechanism 16 Discharge valve 18 Oil seal holding part 19 Compression coil spring (elasticity) Element)
DESCRIPTION OF SYMBOLS 20 Drive apparatus 21 Drive cam 22 Rocker arm 22a Swing end part 22b Base end part 22c Intermediate part 22r Roller 23 Rocker arm support mechanism 24 Pump mounting case (support member)
24a Pump mounting hole portion 24c Pivot holding hole portion 25 Pivot member 25a Base end side shaft portion 25b Pivot portion 25c Flange portion 25h Lubricating oil hole 26 Fallout prevention member 26a Fixed end side portion 26b Free end side portion 27 Compression coil spring (biasing) mechanism)
41, 42 Seal ring

Claims (7)

A driving cam, a rocker arm that engages with the driving cam at an intermediate portion in the longitudinal direction and swings in accordance with the rotation of the driving cam, and supports the rocker arm in a swingable manner in cooperation with the driving cam. A rocker arm support mechanism, and a drive device that reciprocates a driven member that urges a rocking end of the rocker arm in a direction approaching the drive cam in accordance with the rocking of the rocker arm. And
The rocker arm support mechanism is
A pivot member that swingably supports a base end portion of the rocker arm at a first support position in the reciprocating direction of the driven member;
A support member for supporting the pivot member so as to be displaceable from the first support position in the reciprocating direction toward the drive cam;
And a biasing mechanism that biases the pivot member from the first support position toward the drive cam.   When the intermediate portion of the rocker arm is engaged with the drive cam in a state where the swinging end portion of the rocker arm is biased toward the drive cam by an urging force within a certain range, the pivot member is The drive device according to claim 1, wherein the driving device is positioned at the first support position against an urging force of the urging mechanism.   When the urging force by which the driven member urges the rocking end portion of the rocker arm toward the driving cam is reduced out of the predetermined range, the pivot member is moved by the urging force of the urging mechanism. 3. The driving device according to claim 2, wherein the driving device is displaced from the first support position toward the driving cam to displace the rocking end of the rocker arm toward the driven member. 4.   When the pivot member is displaced from the first support position to the drive cam side by the urging force of the urging mechanism and reaches the second support position, the pivot member engages with the base end portion of the rocker arm, 4. The drive device according to claim 3, further comprising a drop-off prevention member that restricts displacement of the base end portion toward the drive cam.   The drive device according to claim 4, wherein the drop-off prevention member is supported by the support member.   The said rocker arm has a roller engaged with the said drive cam so that rolling is possible between the said base end part and the said rocking | fluctuation end part, The Claim 1 thru | or 5 characterized by the above-mentioned. The drive device according to any one of the claims. The driven member is constituted by the input member of a pump device that sucks and discharges fluid into and from the pump body by reciprocating movement of the input member
The said pump apparatus has an elastic member which urges | biases the said input member to the side which approaches the said drive cam, The Claim of any one of Claim 1 thru | or 6 characterized by the above-mentioned. Drive device.

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