JP2002235630A - Fuel injection pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection pump capable of integrally assembling a sub mechanism for storing a cam shaft and a pump driving shaft, a hydraulic head sub mechanism for storing a plunger, a control sleeve, and a distribution means, and a governor mechanism. SOLUTION: The body case sub mechanism 1 is constituted by disposing the cam shaft 4 having a cam reciprocating the plunger 6 and a pump shaft 9 orthogonally linked with the cam shaft and driving an oil feed pump 10 in a body case 24. The hydraulic head sub mechanism 2 is constituted by disposing the distribution shaft 11 having a slit 11b intermittently communicating and intercepting from the crown part of the plunger 6 via a fuel passage 25d and the plunger in a pump case 25. The hydraulic head sub mechanism 2 is mounted on the body case sub mechanism 1, the governor mechanism 3 is added to the side of the body case sub mechanism, and the pump shaft and the distribution shaft are connected together in a part of a stacking surface between the body case and the pump case.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distribution type fuel injection pump for pumping fuel to a fuel injection nozzle disposed in a combustion chamber of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, a fuel injection pump is provided in an internal combustion engine such as a diesel engine. For example, Japanese Patent Application Laid-Open No. 61-218769.

[0003]

There are a line type and a distribution type of fuel injection pump. In the distribution type fuel injection pump, the fuel injection amount changing means, the injection timing changing means, and the distribution means are integrated with the main body case. Although it is desirable to reduce the size of the main body case by assembling it in a compact manner, the processing and assembly of the main body case become complicated, and it takes time and is troublesome to reduce the assembling efficiency. Therefore, the present invention is assembled as a governor mechanism and a sub mechanism for accommodating the cam shaft and the pump drive shaft and a hydraulic head sub mechanism for accommodating the plunger, the control sleeve and the distributing means, and assembling these integrally. An attempt is made to provide a fuel injection pump that can improve assembly efficiency.

[0004]

The present invention uses the following means to solve the above-mentioned problems. According to a first aspect of the present invention, there is provided a distribution type fuel injection pump for distributing and supplying fuel to be injected from one plunger to a fuel injection nozzle arranged for each of a plurality of combustion chambers of an internal combustion engine. A camshaft 4 having a cam to be driven and a pump shaft 9 which is interlockedly connected to the camshaft 4 in a direction perpendicular to the camshaft 4 and drives an oil feed pump 10 are connected to the main body case 24.
And a distributing shaft 11 having a slit 11b for intermittently blocking communication from the top of the plunger 6 via a fuel passage 25d, and the plunger 6 by a pump. The hydraulic head sub-structure 2 is disposed in the case 25, the hydraulic head sub-structure 2 is placed on the main body case sub-structure 1, and the governor mechanism 3 is provided beside the main body case sub-structure 1. Is provided, and the pump shaft 9 and the distribution shaft 11 are connected to each other at a portion where the main body case 24 and the pump case 25 meet.

According to a second aspect of the present invention, in the fuel injection pump according to the first aspect, an insertion hole of a fuel metering member for rotating a plunger in conjunction with the governor mechanism 3 is provided on an upper surface side of the main body case, and a pump shaft. The hydraulic head sub-structure 2 is detachably joined to the upper surface thereof.

According to a third aspect of the present invention, in the fuel injection pump according to the first aspect, a hydraulic head sub mechanism 2 is provided.
Pump case 25 and main body case sub-structure 1
When the main body case 24 is assembled, the insides of the two cases are separated via a sealing member, fuel oil is supplied to the former case, and the latter is lubricated with system oil.

According to a fourth aspect of the present invention, in the fuel injection pump according to the first aspect, a hydraulic head sub-structure 2 is provided.
A plunger assembly in which the plunger, the control sleeve 17 and the upper and lower spring receivers are integrally incorporated via a retaining ring on the lower surface of the pump case 25 constituting the plunger. The pump case 25 and the main body case 24 are inserted into the insertion holes from above to assemble them integrally.

According to the first aspect of the present invention, the plunger drive mechanism and the distributing shaft drive mechanism are oriented vertically, and the plunger fuel metering mechanism and the fuel supply mechanism are respectively positioned from the upper surface of the main body case. The hydraulic head incorporating the distribution mechanism can be easily incorporated from above.

According to the second aspect, the locking piece mounted on the rack enters the insertion hole, and the hydraulic head sub mechanism is assembled on the upper surface thereof, so that it can be easily separated.

According to the third aspect, the seal member can be separated so that fuel on the pump case side does not leak to the main body case and system oil on the main body case does not leak to the pump case side.

According to the fourth aspect, the plunger assembly in which the plunger, the control sleeve 17 and the upper and lower spring receivers are integrally incorporated can be fixed to the pump case by the spring receiving member, and can be easily incorporated into the pump case. ,
Incorporation into the body case is also easy.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a front sectional view of a fuel injection pump of the present invention, FIG. 2 is a side sectional view of the same, FIG. 3 is a perspective view of the same main part, FIG. 4 is a front sectional view of a state where a hydraulic head is removed, and FIG. FIG. 6 is an exploded perspective view of the fuel injection pump, FIG. 7 is a cross-sectional view of a state where the plunger assembly of the hydraulic head sub-structure 2 is inserted into the main body case 24, and FIG. FIG. 9, FIG. 9 is a sectional view showing the same when engaged, FIG. 10 is a plan sectional view of the fuel gallery hole, FIG. 11 is a side sectional view thereof, and FIG. 12 is a plan sectional view showing another embodiment of the timer lever. 13 is a cross-sectional side view of the same, FIG. 14 is a cross-sectional view of an embodiment in which the oil feed pump is disposed over both the main body case 24 and the pump case 25, and FIG. Cross section of the embodiment arranged in the case 24 , 16 is a plan view of the top surface of the body case, FIG. 17 is a side sectional view of a dispensing shaft,
FIG. 18 is a sectional view taken along the line XX in FIG.

In FIG. 1, FIG. 2, FIG. 3, and FIG. 6, the fuel injection pump has a hydraulic head sub-structure 2 mounted on a body case sub-structure 1 and a governor mechanism 3 attached to the side. ing. Body case 24 of body case sub-structure 1
, A cam shaft 4 is laid horizontally in the left-right horizontal direction.
Above is the same number of cam profiles 4a as the number of engine cylinders.
Are formed, the roller 5a of the tappet 5 rides on the cam profile 4a, and the lower portion of the plunger 6 is fitted to the tappet 5. A bevel gear 7 is fixedly mounted on the camshaft 4. The bevel gear 7 meshes with a bevel gear 8. An oil pump 10 is formed and connected to a distribution shaft 11 provided at the upper end of the pump shaft 9 in a hydraulic head sub mechanism 2 described later. As described above, the rotational movement of the camshaft 4 is changed in the right-angle direction by the bevel gears 7 and 8 to constitute a drive mechanism of the distribution shaft 11.

The tip of the camshaft 4 is a camshaft support 12
When the flyweight 13 is opened by centrifugal force, the governor mechanism 3 slides the sliding body 14 to rotate a control sleeve 17 to be described later via the arm 15 and the rack 16. In this way, the injection amount is reduced to control the speed.
The plunger 6 is inserted and arranged from below the pump case 25 of the hydraulic head sub-structure 2. As shown in FIG. 5 and FIG. The wheel 23 is fitted to the lower part of the control sleeve 17 so that the plunger 6 does not drop, and the upper spring receiver 18 is fitted around the outer periphery of the
Further, a plunger spring 19 is fitted over the lower spring support 2.
0, which constitutes a plunger assembly. A notch 18a is provided on the side surface of the upper spring receiver 18,
An upper spring stopper 21 is engaged with the notch 18a. The upper spring stopper 21 is a punched plate having a straight shape on one side, and the straight portion is engaged with the notch 18a to prevent rotation. Stop 21 is screwed to pump case 2
5 Fixed to the bottom.

A projection 17a is projected from the control sleeve 17, and the projection 17a is attached to the governor mechanism 3.
Is engaged with a locking piece 26 serving as a fuel metering member fixed on the rack 16 connected to the rack 16. Therefore, plunger 6
Is urged downward by the plunger spring 19,
The lowest position of the plunger 6 is determined by the control sleeve 17.
By sliding the rack 16 from the governor mechanism, the projection 17a is rotated, and the lowermost position of the plunger 6 is changed. In other words, the fuel metering means is configured such that the stroke of the plunger 6 can be changed to change the fuel supply amount.

Then, on the upper part of the main body case 24,
A plunger insertion hole 24a for inserting the plunger assembly; a locking piece insertion hole 24b for the fuel metering member; and a screw insertion hole 24 for receiving the upper spring receiving 21 and the screw 22.
c, when the hydraulic head sub-assembly 2 is assembled to the main body case 24, the rack 16 is first rotated in the direction of the arrow as shown in FIG. It rotates until it comes into contact with the wall surface of 24b. At this time, a locking piece insertion hole 24b is formed so that the tip of the locking piece 26 can be retracted to a position where it does not interfere with the insertion of the plunger 6 and the spring receivers 18 and 20.
Next, as shown in FIG. 8, the hydraulic head sub mechanism 2 is fitted into the main body case 24 from above, and
4 and a pump case 25, a locking piece 26 and a projection 17a.
When the rack 16 is rotated in the direction of the arrow while visually observing, the engagement can be securely performed, the connection is completed, and when the head bolt is tightened, the main body case 24 and the pump case 25 can be in close contact with each other as shown in FIG.

At the center of the plunger insertion hole of the pump case 25, a fuel gallery hole 25a is opened in the front-rear horizontal direction orthogonal to the plunger insertion hole 25f, and when the plunger 6 is inserted into the pump case 25,
The control sleeve 31 and the timer lever 32 are inserted through the fuel gallery hole 25a, and the control sleeve 31 is fitted to the plunger 6. The configuration of the plunger 6 is such that a hole is opened vertically in the axial center position from the upper end surface to the height at which the control sleeve 31 is located, and a communication hole is opened from the side at the lower end of the hole to form the discharge hole 6a. It is formed. Also,
A lead 6b is formed on a side surface of the plunger 6 at a height where the control sleeve 31 is located, and communicates with the discharge hole 6a.

The side surface of the control sleeve 31 is provided with a fitting recess 31a for engaging the timer lever 32 and a suction / discharge hole 31b communicating with the lead 6b. Fitting recess 31
a is a semicircle in plan view as shown in FIG. 10, and the tip of the timer lever 32 is formed in a square engaging portion 32a. Therefore, the linear portion of the fitting concave portion 31a and the linear portion of the distal end engaging portion 32a of the timer lever 32 contact each other to prevent rotation. And timer lever 3
The second pivot shaft 33 is inserted from the side of the pump case 25, and as shown in FIGS.
The axis O1 serving as a fulcrum and the pivot axis O2 are eccentric in length L0, and the timer lever 32 is moved up and down by rotating the pivot 33 from outside. This allows the control sleeve 31 fitted to the timer lever 32 to move in the vertical direction in conjunction therewith, thereby changing the relative position with respect to the plunger 6 and adjusting the pre-stroke. The initial pre-stroke tends to vary due to variations in component dimensions and the like, so that the use area of the cam changes, causing variations in injection rate, injection amount, etc., leading to variations in engine performance. By providing this adjustment mechanism, such variations can be reduced.

At the other end of the timer lever 32, an engagement protrusion 32b is projected laterally to form a timer piston 34.
Is engaged with an engagement groove 34a formed in an annular shape in the middle part of the first portion. Thus, the timer lever 32 and the timer piston 3
4 and the like constitute timer means. The piston hole 25b into which the timer piston 34 is inserted is vertically opened, and the fuel gallery hole 2 is opened horizontally.
An opening is formed so as to partially overlap 5a, and an elliptical communication hole 25c is formed in the overlapping portion as shown in FIG. The engagement projection 32b is inserted into the engagement groove 34a through the communication hole 25c.

Then, both ends of the fuel gallery hole 25a are covered, and fuel is supplied from the oil supply pump 10 into the fuel gallery hole 25a.
Is proportional to the number of rotations, and the pressure is a force for pushing up the timer piston 34 from the communication hole 25c. A spring 35 is arranged above the timer piston 34 so that the pressure can be adjusted by an adjusting screw 30 arranged above the spring 35. Further, as shown in FIG. 10, the overlapping length L of the piston hole 25b of the timer piston 34 and the fuel gallery hole 25a is the diameter d of the shaft portion where the engagement groove 34a is located from the diameter D of the piston hole 25b. The length is larger than the length of half of the ground [L ≧ (D−d) / 2]. With this configuration, when the timer lever 32 is installed from the fuel gallery hole 25a, the timer piston 3
As a guide, the engagement protrusion 32b enters the engagement groove 34a of No. 4 and positioning can be easily performed.

The length of the timer lever 32 is, as shown in FIG. 11, the distance L1 between the pivot shaft 33 and the engaging projection 32b is determined by the distance L1 between the pivot shaft 33 and the engaging portion 32a. It is configured to be longer than the distance L2. As a second embodiment, the timer lever 32 'can be configured as shown in FIGS. 12 and 13. The timer lever 32' is formed in a substantially Y-shape in plan view, and the distal end of the forked arm is pivoted. Pivoted by 33 ', placing a control sleeve 31 between the arms,
A central engaging portion 32a 'is engaged with the fitting concave portion 31a. In this manner, the pivot shaft 33 and the engaging projection 32
The distance L1 between the pivot shaft 33b and the pivot shaft 33 is longer than the distance L2 between the pivot shaft 33 and the engaging portion 32a.

This means that even if the amount of movement of the control sleeve 31 is smaller than the amount of movement of the timer piston 34 and fluctuations such as pulsations that do not intend to control the fuel pressure in the fuel gallery hole 25a occur, the change is applied to the control sleeve 31. This is because the influence can be reduced. Further, even if the plunger 6 and the control sleeve 31 try to move due to the frictional resistance between the control sleeve 31 and the plunger 6, the moment of the timer piston 34 is large, so that the dragging movement can be suppressed. 1, 2 and 3
As shown in the figure, the pump case 2 above the plunger 6
A delivery guide 36, a delivery valve 37 for closing the shaft hole 36 a thereof, and a delivery spring 38 for urging the delivery valve 37 in the closing direction are provided in 5. A passage 36b is opened in the delivery guide 36 in an oblique direction, and the passage 36b communicates with a fuel passage 25d formed in the pump case 25 to the distribution shaft 11.

The distribution shaft 11 is disposed on an upper extension of the pump shaft 9 and is driven to rotate by the pump shaft 9. An oil feed pump 10 is disposed above the pump shaft 9, and the position of the oil feed pump 10 may be located in the pump case 25 above the mating surface of the main case 24 and the pump case 25 as shown in FIG. 1. , And as shown in FIG.
It can be arranged so as to straddle both the main body case 24 and the pump case 25, or can be configured to be arranged in the main body case 24 below the mating surface as shown in FIG.
In any case, the oil pump 10 can be easily assembled. Then, as shown in FIG. 16, a suction part 10 a of the oil feed pump 10 and a discharge part 10 b are formed on the upper surface of the main body case 24, and further, a return passage 24 g from the discharge side of the plunger 6 to the low pressure side, The plunger insertion hole 24a, the locking piece insertion hole 24b, the screw insertion hole 24c, and the seal insertion groove 2
4j is drilled. The suction portion 10a is provided with a suction passage 24e for sucking fuel from a fuel tank,
It communicates with the side of the body case 24.

Further, a supply passage 24f from the suction portion 10a to an oil seal 39 (FIG. 1) for sealing the lower part of the pump shaft 10 is opened. A relief passage 24d is opened in the discharge section 10b. The seal insertion groove 24i is formed around the return passage 24g, around the suction portion 10a and the discharge portion 10b, around the plunger insertion hole 24a,
The lower end of the timer piston 34 is formed so as to partition around the contact surface 24h. The holes, grooves, and the like formed on the upper surface of the main body case 24 are arranged in a concentrated manner in the main body case 24 manufactured by aluminum die casting capable of forming a complicated shape. A seal packing 40 is inserted into the seal insertion groove 24i to improve the oil tightness of the main body case 24 and the pump case 25, and to separate the fuel passages.

In the pump case 25 into which the distribution shaft 11 is inserted, a distribution shaft insertion hole 25e is provided.
f, the piston hole 25b, the piston hole 25b, the distribution shaft insertion hole 25e, and the plunger insertion
f, the fuel gallery hole 25a, the communication hole, and the like are all round holes so that machining is easy. Are radially opened in the pump case 25 above the distribution shaft 11 in the same number as the number of cylinders, and the distal end thereof communicates with the discharge joints 41, 41. The fuel can be sent from the joints 41 to the injection nozzle.

The distribution shaft 11 communicates with the distribution passage 25g and a fuel passage 25d for sending the fuel discharged from the plunger 6, as shown in FIGS. An annular groove 11a is formed at the end of the passage 25d, and a slit 11b is formed from the annular groove 11a in parallel with the axis.
1a to form one vertical groove 11c,
A corner portion, which is an intersection with the outer periphery of the distribution shaft, is shaved by a plane parallel to the axis to form a plane processed portion 11d. With such a configuration, when the distribution shaft 11 is rotated, if there is a corner, a galling has occurred.
Is provided, the portion becomes obtuse and no galling occurs, and the supply period from the slit to the distribution passage 25g can be extended.

With the above configuration, when the camshaft 4 is rotated, the pump shaft 9 is rotated and the oil feed pump 10 sucks the fuel and feeds the fuel to the fuel gallery hole 25a, and at the same time, the plunger 6 is turned on. The delivery valve 37 is reciprocated.
To the distribution shaft 11 through the fuel passage 25d,
By the rotation of the distribution shaft 11, the distribution passages 25g, 25g,.
The fuel is sent intermittently to the injection nozzle from the discharge joint 41. The engine speed increases, the rack 16 slides by the governor mechanism, the control sleeve 17 rotates, and the amount of fuel discharged by the plunger 6 is adjusted.
The pressure of the fuel discharged from the fuel tank also increases, and the pressure raises and lowers the timer piston 34, rotates the timer lever 32, and raises and lowers the control sleeve 31 to adjust the timing of pressure feeding.

[0028]

The present invention has the following advantages because it is constructed as described above. In other words, since the plunger drive mechanism and the distribution shaft drive mechanism are oriented vertically, the hydraulic head incorporating the plunger fuel metering mechanism and the fuel distribution mechanism from the upper surface of the main body case. It can be easily assembled from above, and can be easily disassembled.

According to the second aspect of the present invention, the locking piece mounted on the rack enters the insertion hole, and the hydraulic head sub mechanism is mounted on the upper surface thereof, so that it can be easily disassembled and assembled. Processing becomes easy.

According to the third aspect of the present invention, the seal member prevents the fuel on the pump case side from leaking to the main body case side and the system oil on the main body case side from leaking to the pump case side, thereby improving oil tightness and lubricating the respective parts. Along with
The fuel injection pressure can be increased.

According to the fourth aspect of the present invention, the plunger assembly in which the plunger, the control sleeve 17 and the upper and lower spring receivers are integrally assembled can be fixed to the pump case with the spring receiving member, and can be easily assembled into the pump case. And it can be easily incorporated into the main body case.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a fuel injection pump according to the present invention.

FIG. 2 is a side sectional view of the same.

FIG. 3 is a perspective view of an essential part of the same.

FIG. 4 is a front sectional view in a state where a hydraulic head is removed.

FIG. 5 is a side view sectional view of the same.

FIG. 6 is an exploded perspective view of the fuel injection pump.

FIG. 7 is a cross-sectional view showing a state in which the plunger assembly of the hydraulic head sub mechanism 2 is inserted into the main body case 24.

FIG. 8 is a cross-sectional view in the same way as in the case of locking.

FIG. 9 is a cross-sectional view of the same when engaged.

FIG. 10 is a plan sectional view of a fuel gallery hole.

FIG. 11 is a side sectional view of the same.

FIG. 12 is a plan sectional view showing another embodiment of the timer lever.

FIG. 13 is a side sectional view of the same.

FIG. 14 is a cross-sectional view of an embodiment in which the oil feed pump is disposed so as to straddle both the main body case 24 and the pump case 25.

FIG. 15 is a perspective view of the main body case 2 below the mating surface of the oil pump
FIG. 4 is a cross-sectional view of the embodiment arranged in FIG.

FIG. 16 is a plan view showing the upper surface of the main body case.

FIG. 17 is a side sectional view of a distribution shaft.

18 is a sectional view taken along the line XX in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body case sub-structure 2 Hydraulic head sub-structure 3 Governor mechanism 4 Cam shaft 6 Plunger 9 Pump shaft 10 Oil feed pump 11 Distribution shaft 17 Control sleeve 24 Body case 25 Pump case 25d Fuel passage

Claims (4)

[Claims] 1. A distribution-type fuel injection pump for distributing and supplying fuel pressure-fed from one plunger 6 to fuel injection nozzles arranged for each of a plurality of combustion chambers of an internal combustion engine.
A camshaft 4 having a cam for reciprocating the plunger 6,
The oil feed pump 10 is linked to the camshaft 4 in an orthogonal direction.
And a pump shaft 9 for driving the main body is disposed in the main body case 24 to form the main body case sub-structure 1. The slit 11b intermittently blocks communication from the top of the plunger 6 via the fuel passage 25d. The distribution shaft 11 and the plunger 6 are arranged in a pump case 25 to form a hydraulic head sub-structure 2, and the hydraulic head sub-structure 2 is placed on the main body case sub-structure 1. A fuel injection pump characterized in that a governor mechanism (3) is attached to a side of a main body case sub-structure (1), and a pump shaft (9) and a distribution shaft (11) are connected at a portion where a main body case (24) and a pump case (25) meet. 2. The fuel injection pump according to claim 1, wherein an insertion hole of a fuel metering member for rotating a plunger in conjunction with the governor mechanism and an insertion hole of a pump shaft are provided on an upper surface side of the main body case. And a fuel suction part, and a hydraulic head sub-structure 2 is detachably joined to an upper surface thereof. 3. The fuel injection pump according to claim 1, wherein when the pump case 25 forming the hydraulic head sub-structure 2 and the main body case 24 forming the main body case sub-structure 1 are connected, the insides of the two cases are separated. A fuel injection pump which is separated through a seal member, supplies fuel oil to the former, and lubricates the latter with system oil. 4. The fuel injection pump according to claim 1, wherein the plunger 6, the control sleeve 17, and the upper and lower spring receivers are integrated with the lower surface of the pump case 25 constituting the hydraulic head sub-structure 2 via retaining rings. A fuel injection pump wherein the pump case 25 and the main body case 24 are assembled integrally by inserting the plunger assembly into the plunger insertion hole opened in the main body case 24 from above. .