JP5255506B2 - Fuel injection pump - Google Patents

Description

  The present invention relates to a fuel injection pump of a fuel injection device mounted on an engine.

  Conventionally, a fuel injection pump configured to drive a camshaft supported by a pump housing from a crankshaft of an engine, reciprocate a plunger in a vertical direction by a cam provided on the camshaft, and pump fuel by the plunger. It is publicly known (see, for example, Patent Document 1). This fuel injection pump stores lubricating oil in a cam chamber formed in a lower portion of a pump housing, and lubricates drive system components such as a cam housed in the cam chamber.

  The fuel injection pump has a lubricating oil discharge hole formed in the pump housing so that the lubricating oil can be discharged from the cam chamber into the gear case connected to the pump housing via the lubricating oil discharge hole. Has been. The lubricating oil discharged to the gear case lubricates the power transmission means for transmitting power from the crankshaft of the engine to the camshaft of the fuel injection pump in the gear case, and lubricates the crankshaft, piston, etc. in the engine. Used for.

  In such a fuel injection pump, a plunger barrel is fitted into a hydraulic head on the pump housing, and the plunger is inserted into the plunger barrel so as to be slidable in the vertical direction. A pressure chamber (fuel pressure chamber) is formed above the plunger in the plunger barrel. A spring for urging the plunger downward is wound around the lower portion of the plunger below the plunger barrel, and a tappet is connected thereto. The tappet is inserted into the tappet chamber so as to be slidable up and down, and is pressed against the cam. The tappet chamber is formed above the cam chamber of the pump housing and communicates with the cam chamber.

JP 2008-106780 A

In the conventional configuration as shown in Patent Document 1, the lubricating oil enters the cam chamber in the pump housing as a droplet through the lubricating oil discharge hole formed in the pump housing, and the lubricating oil in the cam chamber In some cases, the amount of splashes increased.
When the amount of splash of lubricating oil in the cam chamber increases, as shown in FIG. 11, the splash of lubricating oil 82 reaches and adheres to the lower part of the plunger 81, and lubrication is performed by the reciprocating motion of the plunger 81 in the vertical direction. The oil 82 moves upward through the gap between the plunger 81 and the plunger barrel 80, and may be mixed into the fuel 83 through the leak return groove 80 a of the fuel 83. Alternatively, the lubricating oil 82 may continue to rise and enter the pressurizing chamber and get mixed into the fuel 83. Therefore, the amount of the lubricating oil 82 mixed into the fuel 83 is increased, and there is a possibility that problems such as blackening of the fuel 83 and deterioration of engine performance may occur.

  The present invention has been made in view of the problems as described above, and makes it difficult for the splash of lubricant oil from the gear case side connected to the pump housing to enter the pump housing, resulting from the splash of lubricant oil. It is an object of the present invention to provide a fuel injection pump that can suppress mixing of generated lubricating oil into fuel.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  According to a first aspect of the present invention, there is provided a fuel injection pump provided with a pump housing that is connected to a gear case and is capable of communicating with the inside of the gear case. A cover body is provided in the pump housing, and is disposed outside the communication hole of the pump housing so as to face the communication hole, and the communication path is connected to be bent with respect to the communication hole.

  In Claim 2, the through-hole which comprises a part of said communicating path is formed in the said cover body, and it has shifted and arrange | positioned from the position facing the said communicating hole.

  According to a third aspect of the present invention, in the middle of the communication path, a lubricating oil reservoir that can store lubricating oil is provided between the pump housing and the cover body.

  5. The cam housing according to claim 4, wherein a cam chamber for storing a cam is formed in the pump housing, and a tappet chamber for storing the tappet in contact with the cam is formed to communicate with the cam chamber. A blocking portion for blocking these communication is formed between the tappet and the plunger side of the chamber.

  As effects of the present invention, the following effects can be obtained.

  According to the first aspect of the present invention, the communication passage is bent by the bent portion, so that the splash of lubricating oil from the gear case side does not easily enter the pump housing through the communication hole. In addition, the pulsation pressure accompanying the vertical movement of the piston of the engine is attenuated by the plate material, and the pulsation pressure of the fuel injection pump is reduced. Accordingly, it is possible to reduce the amount of splashing of the lubricating oil in the pump housing, and to suppress the mixing of the lubricating oil generated due to the splashing of the lubricating oil into the fuel.

  According to the second aspect of the present invention, since the communication path is bent by the through hole, the splash of lubricating oil from the gear case side hardly enters the pump housing through the communication hole. Accordingly, it is possible to reduce the amount of splashing of the lubricating oil in the pump housing, and to suppress the mixing of the lubricating oil generated due to the splashing of the lubricating oil into the fuel. In addition, the end of the plate member can be attached to the pump housing using a fastener, and the vibration resistance of the cover body can be improved.

  According to the third aspect of the present invention, the pulsation pressure accompanying the vertical movement of the piston of the engine is attenuated by the lubricating oil accumulated in the oil reservoir and does not propagate into the pump housing. Accordingly, it is possible to reduce the amount of splashing of the lubricating oil in the pump housing, and to suppress the mixing of the lubricating oil generated due to the splashing of the lubricating oil into the fuel.

  According to a fourth aspect of the present invention, the splash of lubricating oil in the pump housing is less likely to enter the plunger side than the tappet in the tappet chamber where the fuel is supplied from the cam chamber. Therefore, mixing of the lubricating oil generated in the fuel due to the splashing of the lubricating oil in the pump housing can be suppressed.

FIG. 3 is a right side cross-sectional view showing the overall configuration of the fuel injection pump. FIG. 3 is a front sectional view showing the overall configuration of the fuel injection pump. (A) The front view of the flange which concerns on 1st embodiment of this invention. (B) The front view of the flange which attached the flange cover which concerns on 1st embodiment of this invention. (A) The perspective view of a flange and a flange cover. (B) The perspective view of the flange which attached the flange cover. (A) The front view of the flange cover which concerns on 1st embodiment of this invention. (B) The right view of the flange cover which concerns on 1st embodiment of this invention. (A) The front view of the flange which concerns on 2nd embodiment of this invention. (B) The front view of the flange which attached the flange cover which concerns on 2nd embodiment of this invention. (A) The front view of the flange cover which concerns on 2nd embodiment of this invention. (B) The right view of the flange cover which concerns on 2nd embodiment of this invention. (A) The graph which shows the pulsation pressure of each lubricating oil in the fuel injection pump which concerns on 1st embodiment of this invention, and a gear case. (B) The graph which shows the pulsation pressure of each lubricating oil in the fuel-injection pump and gear case in 2nd embodiment of this invention. The right side sectional view showing the composition near a tappet. The right side sectional view showing the composition near the conventional tappet. The figure which shows the mixing path | route into the fuel of lubricating oil.

Next, an embodiment of the fuel injection pump of the present invention will be described.
In the following description, the front-rear direction is defined with the right-hand direction of FIG. 1 as the front direction, the left-right direction is defined with the front direction of the paper as the right direction, and the up-down direction is defined with the upper direction on the page as the upward direction.

  The fuel injection pump 1 is a part of a fuel injection device mounted on an engine, and is for pumping a predetermined amount of fuel to a fuel injection valve disposed in a cylinder head of the engine at a predetermined timing. . As shown in FIG. 1, the fuel injection pump 1 in this embodiment is a distributed fuel injection pump that distributes and pumps fuel to a fuel injection valve.

  The fuel injection pump 1 is configured by vertically joining a hydraulic head 2 and a pump housing 3.

  A plunger barrel 4 is inserted into the hydraulic head 2, and a plunger 5 is housed in the plunger barrel 4 so as to be slidable up and down. In the hydraulic head 2, a cold start timer mechanism 6 is provided on the left front side of the plunger barrel 4, and an accumulator 7 is provided on the right side of the plunger barrel 4. A pressurizing chamber 8 is formed between the plunger barrel 4 and the upper end portion of the plunger 5.

  In the plunger barrel 4, a leak return groove 4 a is formed in order to reduce a phenomenon (fuel leak) in which fuel leaks from the gap with the plunger 5 and enters the lubricating oil. The leak return groove 4a communicates with a fuel tank (not shown).

A tappet chamber 20 is formed at the front upper part of the pump housing 3 and the lower end of the plunger barrel 4 is inserted. In the tappet chamber 20, the plunger 5 protrudes downward from the lower end portion of the plunger barrel 4.
An upper spring receiver 21 is fixed to the outer periphery of the lower end portion of the plunger barrel 4, and a lower spring receiver 22 is fixed to the lower end portion of the plunger 5. A spring 23 is provided between the upper surface of the lower spring receiver 22 and the lower surface of the upper spring receiver 21 to apply a downward urging force to the plunger 5. A tappet 24 is provided at the lower end portion of the plunger 5 so as to be able to reciprocate in the vertical direction in the tappet chamber 20.

  The tappet 24 has a cylindrical shape opened upward. A lower spring receiver 22 is fixed inside the tappet 24, and the tappet 24 is urged downward together with the plunger 5 by the spring 23 via the lower spring receiver 22. A roller portion 25 is pivotally supported by a lower portion of the tappet 24 via a roller shaft 26. An adjustment shim 27 is provided between the upper surface in the tappet 24 and the lower surface of the lower spring receiver 22.

  A rack chamber 30 is formed at the rear upper part of the pump housing 3 and houses a rack (not shown). A distribution shaft 31 is vertically inserted into the rear portion of the hydraulic head 2, and a lower end portion of the distribution shaft 31 protrudes into the rack chamber 30. A transmission shaft 32 is fixed to the lower end portion of the distribution shaft 31 via the joint 33 on the same axis as the distribution shaft 31. The upper end portion of the transmission shaft 32 is rotatably supported by the shaft support portion 34 of the pump housing 3, and the position in the axial direction (vertical direction) is positioned by the positioning member 35.

  The distribution shaft 31 and the pressurizing chamber 8 are communicated with each other by an oil passage 9 formed in the hydraulic head 2. A delivery valve 10 is provided on the rear side of the distribution shaft 31 in the hydraulic head 2 via a holder 11 for preventing fuel in the injection pipe from flowing into the pressurizing chamber 8 at the end of injection.

  A cam chamber 40 is formed in the lower portion of the pump housing 3. A cam shaft 41 is installed in the cam chamber 40 in the front-rear direction via a first cam bearing 42 and a second cam bearing 43 and is pivotally supported. The cam chamber 40 is filled with lubricating oil, and the cam 44 on the cam shaft 41 is lubricated with this lubricating oil. The cam 44 is formed at the front portion of the pump housing 3, and the roller portion 25 is brought into contact therewith.

  A bevel gear 45 fixed on the cam shaft 41 is accommodated in the rear interior of the cam chamber 40. From the rear upper surface of the cam chamber 40, a lower end portion of a transmission shaft 32 that is pivotally supported by the pump housing 3 and extends in the vertical direction protrudes downward. A bevel gear 46 that meshes with the bevel gear 45 is fixed to the lower end portion of the transmission shaft 32.

  A rear end portion of the cam shaft 41 protrudes rearward from the rear portion of the pump housing 3, and a governor sleeve 12 and a governor weight 13 constituting a governor mechanism are provided in the rear projecting portion of the cam shaft 41.

  A flange 3a is formed in the front portion of the pump housing 3 (in front of the cam chamber 40), and the front end portion of the cam shaft 41 projects forward from the flange 3a. A cam shaft fixing flange 52 is fixed to the front end portion of the cam shaft 41, and a cam shaft driving gear 51 is fixed to the cam shaft fixing flange 52 by a bolt 53. The power from the crankshaft of the engine can be transmitted to the camshaft 41 via the camshaft drive gear 51, power transmission means in the gear case 50 connected to the pump housing 3, and the like.

  Further, in the flange 3a, two lubricating oil discharge holes 3i and 3j are formed as communication holes for communicating the inside of the pump housing 3, that is, the cam chamber 40 and the gear case 50. The lubricating oil in the cam chamber 40 is discharged into the gear case 50 through the two lubricating oil discharge holes 3i and 3j. A flange cover 60 to be described later is attached to these lubricating oil discharge holes 3i and 3j.

In the fuel injection pump 1 having such a configuration, when power is transmitted from the crankshaft to the camshaft 41 and rotated, the cam 44 is rotated together with the rotation of the camshaft 41, and the tappet 24 is reciprocated in the vertical direction. At the same time, the plunger 5 is reciprocated up and down via the lower spring receiver 22 fixed to the tappet 24.
Then, as the plunger 5 reciprocates up and down, the fuel suction stroke into the pressurizing chamber 8 and the fuel discharge stroke from the pressurizing chamber 8 are alternately performed. That is, in the suction stroke, when the plunger 5 is pushed down by the urging force of the spring 23 and descends, the fuel from the fuel tank (feed pump) is sucked into the pressurizing chamber 8. In the discharge stroke, when the plunger 5 is pushed up by the urging force of the spring 23 and rises, the fuel sucked into the pressurizing chamber 8 is pressurized and fed to the distribution shaft 31 through the oil passage 9.
Thereafter, the fuel pumped to the distribution shaft 31 is distributed to the delivery valve 10 by the distribution shaft 31 and injected from the fuel injection nozzle through the injection pipe.

  Next, the configuration of the flange 3a of the pump housing 3 according to the first embodiment will be described.

  As shown in FIGS. 1, 3, and 4, the flange 3a is formed in a substantially triangular shape when viewed from the front. In the flange 3a, a through hole 3d is formed in a substantially circular shape in a front view at the center thereof. The cam shaft 41 is supported in the through hole 3d via the second cam bearing 43 as described above. An annular protrusion 3b is formed on the outer periphery of the through hole 3d so as to protrude forward. The protruding portion 3b can be fitted into a through hole 50a formed in the rear surface of the gear case 50. Then, in a state where the protruding portion 3b is fitted in the through hole 50a of the gear case 50, the bolt is screwed into the mounting hole 3c formed on the outer periphery of the protruding portion 3b, and the flange 3a is fixed to the gear case 50. ing.

  As shown in FIGS. 3A and 4A, a flange recess 3e having a substantially C-shape in front view is formed on the front surface of the protrusion 3b along the circumferential direction of the protrusion 3b. In the flange recess 3e, a plurality of convex ribs 3f, 3f,... Are formed at predetermined intervals in the circumferential direction of the protrusion 3b. Mounting holes 3g and 3h of the flange cover 60 are formed in the uppermost part and the lowermost part of the flange recess 3e, respectively.

  Further, two first lubricating oil discharge holes 3i and a second lubricating oil discharge hole 3j extend linearly in the front-rear direction at the upper right part and the left part in the flange recess 3e, and the cam chamber 40 on the rear end side. And facing the inside of the gear case 50 connected to the pump housing 3 on the front end side. The cam chamber 40 of the pump housing 3 communicates with the inside of the gear case 50 through the first lubricating oil discharge hole 3i and the second lubricating oil discharge hole 3j.

  As shown in FIGS. 3B, 4, and 5, the flange cover 60 that is a cover body has a lubricating oil discharge direction in the first lubricating oil discharge hole 3 i and the second lubricating oil discharge hole 3 j, that is, the front-rear direction. The plate is made of a resin or metal plate having a plane extending in a direction orthogonal to the shape, and is formed in a substantially C shape in front view with a part of the ring cut out. The flange cover 60 has a shape similar to that of the flange recess 3e in a front view, and has a surface area slightly smaller than that of the flange recess 3e. The circumferential length of the flange cover 60 is made shorter than the circumferential length of the flange recess 3e.

  The flange cover 60 is configured to be uneven by a first flat portion 60a, a first concave portion 60b recessed backward, a second flat portion 60e, and a second concave portion 60f recessed backward. In the flange cover 60 having a substantially C shape when viewed from the front, each part is arranged in the order of the first flat part 60a, the first concave part 60b, the second flat part 60e, and the second concave part 60f in the clockwise direction when viewed from the front.

  The flange cover 60 is fitted to the flange recess 3e so that the first recess 60b is located at the top, the second recess 60f is located at the bottom, and the second flat portion 60e is located at the left. Is done. At the time of this fitting, the first lubricating oil discharge hole 3i and the second lubricating oil discharge hole 3j are completely covered by the flange cover 60 in a front view. Attachment holes 60c and 60g for attaching the flange cover 60 to the flange 3a are formed at the upper, lower, left and right centers of the recesses 60b and 60f. A discharge hole 60h, which is a through hole, is formed in the lower portion of the second flat surface portion 60e.

  Such a flange cover 60 is fitted into the flange recess 3e of the flange 3a, the mounting holes 60c and 60g of the flange cover 60 are made to coincide with the mounting holes 3g and 3h of the flange recess 3e, respectively, and the bolts 61 and 61 are attached. Inserted into the mounting holes 60c and 60g from the outside of the pump housing 3 and screwed into the mounting holes 3g and 3h. Thus, the flange cover 60 is attached to the flange 3a in a state where the flange cover 60 is disposed to face the first lubricating oil discharge hole 3i (see FIGS. 3B and 4B).

  When the flange cover 60 is attached to the flange 3a in this way, as shown in FIG. 3B, the position where the first flat surface portion 60a of the flange cover 60 faces the first lubricating oil discharge hole 3i of the flange 3a. Will be placed. In other words, the first lubricating oil discharge hole 3i and the first flat surface portion 60a are arranged so as to overlap in a front view. At this time, the flange cover 60 comes into contact with the ribs 3f, 3f..., And a space is formed between the flange cover 60 and the flange recess 3e except for the contact portion.

  Therefore, the lubricating oil discharged from the first lubricating oil discharge hole 3i in the pump housing 3 comes out from the first lubricating oil discharge hole 3i and then comes to the front and rear in the first flat surface portion 60a of the flange cover 60. It is changed from the direction to the substantially vertical direction, and is formed between the right end portion of the first flat portion 60a and the right end portion of the flange concave portion 3e through the space between the first flat portion 60a and the flange concave portion 3e. The gap 60d flows from here into the gear case 50 as a discharge hole. Here, the gap 60d is arranged so as to be deviated from the position facing the first lubricating oil discharge hole 3i.

  That is, a bent portion is formed by the flange cover 60 in the communication passage that connects the cam chamber 40 of the pump housing 3 and the inside of the gear case 50 together with the first lubricating oil discharge hole 3i, here, the lubricating oil discharge passage. The lubricating oil discharged from the one lubricating oil discharge hole 3i does not flow linearly into the gear case 50, flows through the space between the flange cover 60 and the flange 3a, and then enters the gear case 50 through the gap 60d. Will flow.

  Therefore, even when the lubricating oil scatters toward the first lubricating oil discharge hole 3i of the pump housing 3 in the gear case 50, the lubricating oil splashes near the first lubricating oil discharge hole 3i in the vicinity of the flange cover 60. The first flat surface portion 60a is prevented from entering the first lubricating oil discharge hole 3i. Further, even when the lubricant splashes reach the gap 60d, it must pass through the bent portion of the discharge passage formed by the flange cover 60 and is difficult to enter the first lubricant discharge hole 3i.

  Similarly, when the flange cover 60 is attached to the flange 3a, the second flat surface portion 60e of the flange cover 60 is disposed at a position facing the second lubricating oil discharge hole 3j of the flange 3a. In other words, the second lubricating oil discharge hole 3j and the second flat surface portion 60e are arranged so as to overlap in a front view.

  Therefore, after the lubricating oil discharged from the second lubricating oil discharge hole 3j in the pump housing 3 comes out of the second lubricating oil discharge hole 3j, the discharge direction of the second flat surface portion 60e of the flange cover 60 is substantially changed back and forth. The direction is changed from the direction to the substantially vertical direction, and flows into the gear case 50 from the discharge hole 60h formed in the second plane part 60e through the space between the second plane part 60e and the flange recess 3e. Here, the discharge hole 60h is arranged so as to be deviated from the directly-facing position with the second lubricating oil discharge hole 3j.

  That is, a bent portion is formed by the flange cover 60 in the communication passage that connects the cam chamber 40 of the pump housing 3 and the inside of the gear case 50 together with the second lubricating oil discharge hole 3j, here the lubricating oil discharge passage. The lubricating oil discharged from the two lubricating oil discharge holes 3j does not flow linearly into the gear case 50, flows through the space between the flange cover 60 and the flange 3a, and then enters the gear case 50 through the discharge hole 60h. Will flow in.

  Therefore, even when the lubricating oil scatters toward the second lubricating oil discharge hole 3j side of the pump housing 3 in the gear case 50, the splash of the lubricating oil is near the second lubricating oil discharge hole 3j near the flange cover 60. The first flat surface portion 60a is prevented from entering the first lubricating oil discharge hole 3i. Further, even when the lubricant splashes reach the discharge hole 60h, it must pass through the bent portion of the discharge passage formed by the flange cover 60 and is difficult to enter the second lubricant discharge hole 3j.

  As a result, the lubricant enters the cam chamber 40 in the pump housing 3 from the gear case 50 as a splash through the first lubricant discharge hole 3i and the second lubricant discharge hole 3j formed in the pump housing, and the cam chamber It can be reduced that the amount of the lubricant splashed at 40 increases. As a result, the splash of lubricating oil reaches and adheres to the lower part of the plunger 5, and by the reciprocating motion of the plunger 5 in the vertical direction, the lubricating oil passes through the gap between the plunger 5 and the plunger barrel 4 and leaks into the leak return groove 4 a or It is possible to suppress entry into the pressure chamber 8 and mixing with the fuel.

  Next, the configuration of the flange 3A according to the second embodiment will be described. However, the same members as those of the configuration of the first embodiment are denoted by the same reference numerals, and description will be made focusing on portions different from the first embodiment.

  As shown in FIG. 6A, the flange 3A is formed in a substantially triangular shape when viewed from the front. In the flange 3a, an annular protrusion 3B is formed at the center of the front surface so as to protrude forward. A flange recess 3E having a substantially C shape in front view that is recessed rearward is formed on the outer periphery of the through hole 3d. A cover support portion 3K formed in a step shape is formed on the outer peripheral portion in the flange recess 3E. A mounting hole 3G for the flange cover 70, which is a cover body, is formed in the lower right portion of the flange recess 3E.

  Further, in the lower right part in the flange recess 3E, two lubricating oil discharge holes 3I and 3I which are through holes extend linearly in the front-rear direction, face the cam chamber 40 on the rear end side, and pump on the front end side. It is formed so as to face the gear case 50 connected to the housing 3, and is disposed so as to sandwich the mounting hole 3G. The cam chamber 40 of the pump housing 3 communicates with the inside of the gear case 50 through these lubricating oil discharge holes 3I and 3I.

  As shown in FIGS. 6B and 7, the flange cover 70 is made of resin or metal having a plane extending in a direction perpendicular to the direction in which the lubricating oil is discharged in the lubricating oil discharge holes 3 </ b> I and 3 </ b> I, that is, the front-rear direction. It is made of a plate material and is formed in a substantially C shape when viewed from the front. The flange cover 70 has a similar shape to a part of the flange recess 3E in a front view, and has a surface area slightly smaller than a part of the flange recess 3E. The circumferential length of the flange cover 70 is shorter than the circumferential length of the flange recess 3E.

  The flange cover 70 includes a flat surface portion 70a and a cutout portion 70c. In the flange cover 70, the flat surface portion 70 a is disposed over the entire circumferential direction of the flange cover 70, and the notch portion 70 c is disposed on the outer peripheral side of the midway portion of the flange cover 70 in the circumferential direction.

  The flange cover 70 is fitted to the lower portion of the flange recess 3E so that the cutout portion 70c is located at the lowermost portion thereof. At the time of this fitting, the two lubricating oil discharge holes 3I and 3I are completely covered by the flange cover 70 in a front view. An attachment hole 70b for attaching the flange cover 70 to the flange 3a is formed at the center of the flat surface portion 70a.

  The flange cover 70 is fitted into the flange recess 3E of the flange 3A, the mounting hole 70b of the flange cover 70 is made to coincide with the mounting hole 3G, and the bolts 61 and 61 are moved from the outside of the pump housing 3 to the mounting hole 70b. Insert and screw into the mounting hole 3G. In this way, the flange cover 70 is attached to the flange 3A in a state where the flange cover 70 is disposed opposite to the two lubricating oil discharge holes 3I and 3I.

  Thus, when the flange cover 70 is attached to the flange 3A, the flat surface portion 70a of the flange cover 70 is disposed at a position facing the two lubricating oil discharge holes 3I and 3I of the flange 3A. In other words, the two lubricating oil discharge holes 3I and 3I and the flat surface portion 70a are overlapped with each other when viewed from the front. At this time, the flange cover 70 comes into contact with the cover support portion 3K, and a space is formed between the flange cover 70 and the flange recess 3E except for the contact portion.

  Therefore, the lubricating oil discharged from the two lubricating oil discharge holes 3I and 3I in the pump housing 3 is substantially directed to the flat surface portion 70a of the flange cover 70 after being discharged from the respective lubricating oil discharge holes 3I and 3I. It was changed from the front-rear direction to a substantially vertical direction, and formed between the left and right side ends of the flange recess 3E and the left and right sides of the flange recess 3E through the space between the flat surface portion 70a and the flange recess 3E. The gap 70d flows into the gear case 50 from here as a discharge hole. Here, the gap 70d is arranged so as to be deviated from the position facing the lubricating oil discharge holes 3I and 3I.

  That is, a bent portion is formed by the flange cover 60 in the communication passage that connects the cam chamber 40 of the pump housing 3 and the inside of the gear case 50 together with the lubricating oil discharge holes 3I and 3I. Lubricating oil discharged from the lubricating oil discharge holes 3I and 3I does not flow linearly into the gear case 50, flows through the space between the flange cover 70 and the flange 3A, and then enters the gear case 50 through the gap 70d. Will flow in.

  The lubricating oil discharged from the lubricating oil discharge holes 3I and 3I once accumulates in a space formed between the flange recess 3E and the flat portion 70a of the flange cover 70, and then enters the gear case 50 through the gap 70d. Will flow in. In this way, a lubricating oil reservoir is provided between the pump housing 3 and the flange cover 70 in the middle of the discharge passage connecting the cam chamber 40 and the gear case 50. In the present embodiment, the lubricating oil in the lubricating oil reservoir portion flows into the gear case 50 through a gap formed between the notch portion 70c of the flange cover 70 and the flange concave portion 3E.

  Therefore, even when the lubricating oil scatters to the lubricating oil discharge holes 3I and 3I side of the pump housing 3 in the gear case 50, the lubricating oil splashes in the vicinity of the positions facing the lubricating oil discharge holes 3I and 3I are flanges. In the flat portion 70a of the cover 70, entry into the lubricating oil discharge holes 3I and 3I is prevented. Further, even when the lubricant splashes reach the gap 70d, it must pass through the bent portion of the discharge passage formed by the flange cover 70, and is difficult to enter the lubricant discharge holes 3I and 3I.

  As a result, the lubricating oil splashes into the cam chamber 40 in the pump housing 3 from the gear case 50 through the lubricating oil discharge holes 3I and 3I formed in the pump housing, and the amount of the lubricating oil splashing in the cam chamber 40 is reduced. The increase can be reduced. As a result, the splash of lubricating oil reaches and adheres to the lower part of the plunger 5, and by the reciprocating motion of the plunger 5 in the vertical direction, the lubricating oil passes through the gap between the plunger 5 and the plunger barrel 4 and leaks into the leak return groove 4 a or It is possible to suppress entry into the pressure chamber 8 and mixing with the fuel.

In the fuel injection pump 1, as shown in FIG. 10, when the lower spring receiver 22 and the adjustment shim 27 are provided with vertical through holes 22 a and 27 a, the roller portion 25 of the tappet 24 is connected to the cam 44. Since it rotates in contact and rotates, the lubricating oil supplied to the cam 44 is lifted by the rotation of the roller portion 25 and flows into the plunger 5 side from the tappet 24 of the tappet chamber 20 through the through holes 22a and 27a. Furthermore, there is a possibility that the leak return groove 4a or the pressurizing chamber 8 enters the gap between the plunger 5 and the plunger barrel 4 and enters the fuel.
Therefore, in the present embodiment, the fuel injection pump 1 has a structure in which the lower spring receiver 22 and the adjustment shim 27 are not provided with vertical through holes, as shown in FIG. As a result, a blocking portion 28 is formed between the roller portion 25 of the tappet 24 and the lower spring receiver 22 to prevent the lubricating oil adhering to the roller portion 25 of the tappet from entering the tappet 24 and into the fuel. The amount of lubricating oil transferred can be reduced.

  As described above, the fuel injection pump 1 according to the embodiment of the present invention is the fuel injection pump 1 provided with the pump housing 3 connected to the gear case 50 and capable of communicating with the inside of the gear case 50. 3, a first lubricating oil discharge hole 3 i, a second lubricating oil discharge hole 3 j, and a communication path 3 k are provided in the pump housing 3, and the first lubricating oil discharge hole 3 i of the pump housing 3 is provided. The flange cover 60 is disposed outside the second lubricating oil discharge hole 3j so as to face the first lubricating oil discharge hole 3i and the second lubricating oil discharge hole 3j, and the communication passage 3k is connected to the first lubricating oil. The oil discharge hole 3i and the second lubricating oil discharge hole 3j are connected so as to be bent.

  Thereby, since the discharge path of the lubricating oil from the pump housing 3 is bent by the bent portion, the splashing of the lubricating oil from the gear case 50 side hardly enters the pump housing 3. In addition, the pulsation pressure accompanying the vertical movement of the piston of the engine is attenuated by the cover body, and the pulsation pressure of the fuel injection pump 1 is reduced. Accordingly, it is possible to reduce the amount of splashing of the lubricating oil in the pump housing 3 and to suppress the mixing of the lubricating oil generated due to the splashing of the lubricating oil into the fuel.

  In addition, when the flange cover 60 is attached to the flange 3a according to the first embodiment, the pulsation pressure in the pump housing 3 is, as a specific example, pulsation in the gear case 50 as shown in FIG. It is attenuated to about 60% compared to the pressure.

  Further, when the flange cover 70 is attached to the flange 3A according to the second embodiment, the pulsation pressure in the pump housing 3 is, as a specific example, pulsation in the gear case 50 as shown in FIG. It is attenuated to almost zero compared to the pressure.

  In the fuel injection pump 1 according to the embodiment of the present invention, the exhaust hole 60h constituting a part of the communication path 3k is formed in the flange cover 60, and the first lubricating oil discharge hole 3i and the second lubricating oil are formed. The position is shifted from the position facing the discharge hole 3j.

  Accordingly, the lubricating oil discharge path from the pump housing 3 is further bent by the through-hole, so that the splashing of lubricating oil from the gear case 50 side does not easily enter the pump housing 3. Accordingly, it is possible to reduce the amount of splashing of the lubricating oil in the pump housing 3 and to suppress the mixing of the lubricating oil generated due to the splashing of the lubricating oil into the fuel. In addition, the end of the flange cover 60 can be attached to the pump housing 3 using a fastener, and the vibration resistance of the flange cover 60 can be improved.

  Further, the fuel injection pump 1 according to the embodiment of the present invention includes a lubricating oil reservoir 3M capable of storing lubricating oil in the middle of the communication path 3k and between the pump housing 3 and the flange cover 60. Is provided.

  As a result, the pulsation pressure associated with the vertical movement of the piston of the engine is attenuated by the lubricating oil accumulated in the lubricating oil reservoir 3M and does not propagate into the pump housing 3. Accordingly, it is possible to reduce the amount of splashing of the lubricating oil in the pump housing 3 and to suppress the mixing of the lubricating oil generated due to the splashing of the lubricating oil into the fuel.

  The pump housing 3 is formed with a cam chamber 40 for accommodating the cam 44, and a tappet chamber 20 for accommodating the tappet 24 in contact with the cam 44 is formed so as to communicate with the cam chamber 40. The cam chamber 40 and the tappet 24 of the tappet chamber 20 between the plunger 5 side and the cam chamber 40 are formed with a blocking portion 28 that prevents these communication.

  Thereby, the splash of the lubricating oil in the pump housing 3 becomes difficult to enter the pressurizing chamber 8 side where the fuel is supplied from the cam chamber 40. Therefore, it is possible to suppress the mixture of the lubricating oil generated due to the splashing of the lubricating oil in the pump housing 3 into the fuel.

1 Fuel Injection Pump 2 Hydraulic Head 3 Pump Housing 3a Flange 3i First Lubricating Oil Discharge Hole (Communication Hole)
3j Second lubricating oil discharge hole (communication hole)
3k communication passage 3I Lubricating oil discharge hole (communication hole)
3M Lubricating oil reservoir 28 Blocking section 50 Gear case 60 Flange cover (cover body)
60d Clearance 60h Discharge hole (through hole)

Claims (4)

A fuel injection pump provided with a pump housing connected to a gear case and capable of communicating with the inside of the gear case,
A communication hole and a communication path for communicating the inside of the pump housing and the inside of the gear case are provided in the pump housing,
A fuel injection pump in which a cover body is disposed outside the communication hole of the pump housing so as to face the communication hole, and the communication path is bent with respect to the communication hole.   The fuel injection pump according to claim 1, wherein a through-hole constituting a part of the communication passage is formed in the cover body and is shifted from a position facing the communication hole.   3. The fuel injection pump according to claim 1, wherein a lubricating oil reservoir that can store lubricating oil is provided in the middle of the communication path and between the pump housing and the cover body. Forming a cam chamber for storing a cam in the pump housing, and forming a tappet chamber for storing a tappet in contact with the cam so as to communicate with the cam chamber;
The fuel injection pump according to any one of claims 1 to 3, wherein a blocking portion for blocking communication between the cam chamber and the tappet chamber is formed between the tappet chamber and the plunger side.

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