JP3734757B2 - Fuel injection pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a distribution type fuel injection pump configured to pump fuel to a fuel injection nozzle disposed in a combustion chamber of an internal combustion engine.
[0002]
[Prior art]
Conventionally, a fuel injection pump is provided in an internal combustion engine such as a diesel engine. For example, there is a technique disclosed in JP-A-61-218769.
[0003]
[Problems to be solved by the invention]
There are two types of fuel injection pumps: a distribution type and a distribution type. In the distribution type fuel injection pump, the fuel injection amount changing means, the injection timing changing means, and the distributing means are integrally provided in the main body case for compactness. However, the configuration is complicated, and the processing and assembly of the main body case are complicated, which takes time and is troublesome, and the assembly efficiency is reduced.
Therefore, the present invention is assembled as a sub mechanism for storing the camshaft and the pump drive shaft, a hydraulic head sub mechanism for storing the plunger, the control sleeve, and the distributing means and a governor mechanism, and these are assembled integrally. A fuel injection pump capable of improving assembly efficiency is provided.
[0004]
[Means for Solving the Problems]
The present invention uses the following means in order to solve the above problems.
In claim 1, the fuel injection nozzle disposed for each of a plurality of combustion chamber of an internal combustion engine, in distributor type fuel injection pump for supplying and distributing a fuel for pumping from one plunger 6, reciprocating the plunger 6 A camshaft 4 having a cam to be moved and a pump shaft 9 linked to the camshaft 4 in an orthogonal direction to drive the oil feed pump 10 are disposed in the main body case 24 and are arranged in the main body case sub-structure 1. The distribution shaft 11 having a slit 11b intermittently cut off from the top of the plunger 6 through a fuel passage 25d and the plunger 6 are disposed in a pump case 25 to provide a hydraulic head. as sub mechanism 2, placing the hydraulic head sub mechanism 2 on the main body casing sub mechanism 1, and attaching a governor mechanism 3 further to the side of the main body case sub mechanism 1, the pump shaft The oil feeding pump 10 driven by the pump shaft 9 is disposed on the mating surface portion of the main body case 24 and the pump case 25, and the fuel is sucked from the fuel tank by the oil feeding pump 10 into the plunger 6. Further, the distribution shaft 11 is arranged on the extension to the pump shaft 9, and the pump shaft 9 and the distribution shaft 11 are connected .
[0005]
In claim 2, the fuel injection pump according to claim 1, wherein the upper surface side of the main body case 24, an insertion hole of the fuel metering member which rotates the plunger in conjunction with the governor mechanism 3, pump shaft 9 And a suction part 10a to the oil feed pump 10, and the hydraulic head sub mechanism 2 is detachably joined to the upper surface thereof.
[0006]
In claim 3, in the fuel injection pump according to claim 1, when the pump case 25 constituting the hydraulic head sub mechanism 2 and the main body case 24 constituting the main body case sub mechanism 1 are coupled, the pump case 25 And the main body case 24 are separated through a seal member, fuel oil is supplied to the former, and the latter is lubricated with system oil.
[0007]
According to a fourth aspect of the present invention, in the fuel injection pump according to the first aspect, the plunger 6, the control sleeve 17, and the upper and lower spring receivers are disposed on the lower surface of the pump case 25 constituting the hydraulic head sub mechanism 2 via a retaining ring. The integrally assembled plunger assembly is inserted into the plunger insertion hole opened in the main body case 24 from above, and the pump case 25 and the main body case 24 are assembled together.
[0008]
By using such means,
According to the first aspect of the present invention, the plunger drive mechanism and the distribution shaft drive mechanism are oriented vertically, and the hydraulic head incorporating the fuel metering mechanism of the plunger and the fuel distribution mechanism can be easily viewed from above from the upper surface of the main body case. Can be incorporated into.
[0009]
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.
[0010]
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 side and system oil on the main body case side does not leak to the pump case side.
[0011]
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 incorporated can be fixed to the pump case with the spring receiving member, and can be easily assembled into the pump case. Can be easily incorporated into
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings.
1 is a front sectional view of the fuel injection pump according to the present invention, FIG. 2 is a sectional side view, FIG. 3 is a perspective view of the main part, FIG. 4 is a front sectional view of the hydraulic head removed, and FIG. FIG. 6 is an exploded perspective view of the fuel injection pump, FIG. 7 is a sectional view of the hydraulic head sub mechanism 2 with the plunger assembly inserted into the main body case 24, and FIG. FIG. 9 is a sectional view in the same manner, FIG. 10 is a sectional plan view of the fuel gallery hole, FIG. 11 is a sectional side view, and FIG. 12 is a sectional plan view showing another embodiment of the timer lever. 13 is a side cross-sectional view, FIG. 14 is a cross-sectional view of an embodiment in which an oil feeding pump is disposed across both the main body case 24 and the pump case 25, and FIG. 15 is a main body below the mating surface. Cross section of the embodiment placed 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 axis, FIG. 18 is a X-X in arrow sectional view in FIG. 17.
[0013]
1, 2, 3, and 6, the fuel injection pump has a hydraulic head sub-structure 2 mounted on a main body case sub-structure 1 and a governor structure 3 attached to the side.
The main body case 24 of the main body case sub-structure 1 has a cam shaft 4 mounted horizontally in the horizontal direction, and cam profiles 4a, 4a,... As many as the number of engine cylinders are formed on the cam shaft 4. The roller 5a of the tappet 5 is placed on the cam profile 4a, and the lower portion of the plunger 6 is fitted to the tappet 5.
Further, a bevel gear 7 is fixed on the cam shaft 4, the bevel gear 7 meshes with the bevel gear 8, the bevel gear 8 is fixed to the lower end of the pump shaft 9, and a rotary pressure feed type feed is provided on the top of the pump shaft 9. An oil pump 10 is formed, and is connected to a distribution shaft 11 provided in a hydraulic head sub mechanism 2 described later at the upper end of the pump shaft 9. In this way, the rotational movement of the cam shaft 4 is changed in the right-angle direction by the bevel gears 7 and 8 to constitute the drive mechanism for the distribution shaft 11.
[0014]
The tip of the camshaft 4 is supported by a camshaft support 12 and inserted into the governor mechanism 3. When the flyweight 13 is opened by centrifugal force, the governor mechanism 3 slides the sliding body 14 to form an arm 15 and a rack 16. The control sleeve 17 which will be described later is rotated via this to reduce the injection amount so that the speed can be adjusted.
Further, the plunger 6 is arranged to be inserted from below the pump case 25 of the hydraulic head sub mechanism 2, and as shown in FIG. 5 and FIG. A ring 23 is fitted to the lower part of the control sleeve 17 so that the plunger 6 does not fall, an upper spring receiver 18 is fitted on the outer periphery, a plunger spring 19 is further fitted and received by the lower spring holder 20, and the plunger assembly is mounted. It is composed.
A cutout 18a is provided on the side surface of the upper spring receiver 18, and an upper spring catch 21 is engaged with the notch 18a. The upper spring catch 21 is a punched plate having a linear shape on one side. Is engaged with the notch 18 a to prevent rotation, and the upper spring catch 21 is fixed to the bottom surface of the pump case 25 with a screw 22.
[0015]
Further, the control sleeve 17 has a projection 17a that is engaged with a locking piece 26 serving as a fuel metering member fixed on the rack 16 connected to the governor mechanism 3. Accordingly, the plunger 6 is urged downward by the plunger spring 19, and the lowest position of the plunger 6 is determined by the control sleeve 17. By sliding the control sleeve 17 from the governor mechanism on the rack 16, the projection 17a is moved. The plunger 6 is rotated to change the lowest position of the plunger 6. That is, the fuel metering means is configured by changing the stroke of the plunger 6 so as to change the fuel supply amount.
[0016]
In 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 a fuel metering member, an upper spring catch 21 and a screw 22 are housed. When the hydraulic head sub mechanism 2 is assembled to the main body case 24, the rack 16 is first rotated in the direction of the arrow and the end of the locking piece 26 is locked. It rotates until it contacts the wall surface of the one-side insertion hole 24b. At this time, a locking piece insertion hole 24b is configured so that the tip of the locking piece 26 can be retracted to a position where it does not interfere when the plunger 6 and the spring receivers 18 and 20 are inserted. Next, as shown in FIG. 8, the hydraulic head sub mechanism 2 is fitted into the main body case 24 from above, and the locking piece 26 and the protrusion 17a are visually observed in the gap between the main body case 24 and the pump case 25 in the direction of the arrow. When the rack 16 is rotated and securely locked, the connection is completed, and the head bolt is tightened, the main body case 24 and the pump case 25 can be brought into close contact as shown in FIG.
[0017]
A fuel gallery hole 25a is opened in the front / rear horizontal direction perpendicular to the plunger insertion hole 25f at the center of the plunger insertion hole of the pump case 25, and the fuel gallery is inserted when the plunger 6 is inserted into the pump case 25. The control sleeve 31 and the timer lever 32 are inserted from the hole 25a, and the control sleeve 31 is externally fitted to the plunger 6. The plunger 6 has a structure in which a hole is opened vertically from the upper end surface to a height at which the control sleeve 31 is positioned, and a communication hole is opened from the side at the lower end of the hole. It is formed. A lead 6b is formed on the side surface of the plunger 6 where the control sleeve 31 is located, and communicates with the discharge hole 6a.
[0018]
On the side surface of the control sleeve 31, a fitting recess 31a for engaging the timer lever 32 and an intake / exhaust hole 31b capable of communicating with the lead 6b are opened. The fitting recess 31a has a semicircular shape in plan view as shown in FIG. 10, and the tip of the timer lever 32 is formed in a rectangular engaging portion 32a. Accordingly, the straight portion of the fitting recess 31a and the straight portion of the tip engaging portion 32a of the timer lever 32 are in contact with each other to prevent rotation.
The pivot shaft 33 of the timer lever 32 is inserted from the side surface of the pump case 25, and as shown in FIGS. 10 and 11, an axis O1 serving as a fulcrum of the timer lever 32 and a pivot shaft rotation axis. O2 is configured to have an eccentric length L0. By rotating the pivot shaft 33 from the outside, the timer lever 32 can be moved in the vertical direction. The control sleeve 31 fitted to the timer lever 32 is also provided. It can move in conjunction with the vertical direction, can change the relative position with the plunger 6, and can adjust the prestroke.
The initial prestroke is likely to vary due to variations in component dimensions, etc., so that the cam usage area changes, causing variations in the injection rate, injection amount, etc., leading to variations in engine performance. By providing this adjustment mechanism, the variation can be reduced.
[0019]
Then, the other end of the timer lever 32 protrudes from the side to an engagement protrusion 32b and engages with an engagement groove 34a formed in an annular shape in the middle of the timer piston 34. Thus, the timer lever 32, the timer piston 34, etc. constitute timer means. A piston hole 25b into which the timer piston 34 is inserted is opened in the vertical direction so as to partially overlap the fuel gallery hole 25a opened in the lateral direction, and the overlapping part is elliptical as shown in FIG. The communication hole 25c is formed. The engaging protrusion 32b is inserted into the engaging groove 34a through the communication hole 25c.
[0020]
Then, both ends of the fuel gallery hole 25a are covered, and fuel is fed from the oil pump 10 into the fuel gallery hole 25a. The oil feed pressure is proportional to the rotational speed of the camshaft 4, and the pressure is This is the force that pushes up the timer piston 34 from the communication hole 25c. A spring 35 is disposed on the timer piston 34, and the pressure can be adjusted by an adjusting screw 30 disposed on 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 obtained by changing the diameter d of the shaft portion where the engaging groove 34a is located from the diameter D of the piston hole 25b. The length is larger than half the length [L ≧ (D−d) / 2]. With this configuration, when the timer lever 32 is assembled from the fuel gallery hole 25a, the engagement protrusion 32b is inserted into the engagement groove 34a of the timer piston 34, and positioning can be performed easily.
[0021]
Further, as shown in FIG. 11, the length of the timer lever 32 is such that the distance L1 between the pivot shaft 33 and the engagement protrusion 32b is larger than the distance L2 between the pivot shaft 33 and the engagement portion 32a. It also has a long structure. Further, as a second embodiment, it can be configured as shown in FIGS. 12 and 13, the timer lever 32 ′ is configured in a substantially Y shape in plan view, and the bifurcated arm tip is pivotally supported. The control sleeve 31 is pivotally supported by 33 ', the control sleeve 31 is disposed between the arms, and the engaging portion 32a' at the center is engaged with the fitting recess 31a.
Thus, in this second embodiment and the above-described embodiment, the distance L1 between the pivot shaft 33 and the engagement protrusion 32b is the distance between the pivot shaft 33 and the engagement portion 32a. It is longer than L2.
[0022]
This is because the amount by which the control sleeve 31 is moved is smaller than the amount by which the timer piston 34 is moved, and even if fluctuations such as pulsations that do not intend to control the fuel pressure in the fuel gallery hole 25a occur, the influence on the control sleeve 31 is reduced. This is because it can. Further, even if the plunger 6 and the control sleeve 31 are moved by the frictional resistance between the control sleeve 31 and the plunger 6, the moment on the timer piston 34 side is large, so that the dragging movement can be suppressed.
As shown in FIGS. 1, 2, and 3, a delivery guide 36, a delivery valve 37 capable of closing the axial hole 36 a in the pump case 25 above the plunger 6, and the delivery A delivery spring 38 that urges the valve 37 in the closing direction is provided. A passage 36 b is opened in the delivery guide 36 in an oblique direction, and the passage 36 b communicates with a fuel passage 25 d to the distribution shaft 11 formed in the pump case 25.
[0023]
The distribution shaft 11 is disposed on the upper extension of the pump shaft 9 and is rotationally driven by the pump shaft 9. An oil feed pump 10 is arranged on the upper part of the pump shaft 9, and the position of the oil feed pump 10 may be arranged in a pump case 25 above the mating surface of the main body case 24 and the pump case 25 as shown in FIG. Further, as shown in FIG. 14, it is arranged so as to straddle both the main body case 24 and the pump case 25, as shown in FIG. 15, so as to be arranged in the main body case 24 below the mating surface. In any case, the oil pump 10 can be easily assembled.
And as shown in FIG. 16, the suction part 10a of the oil feeding pump 10 and the discharge part 10b are formed in the upper surface of the main body case 24, and also the return path 24g 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 24j are formed. A suction passage 24e for sucking fuel from the fuel tank is opened in the suction portion 10a and communicates with the side surface of the main body case 24.
[0024]
Further, a supply passage 24f is opened from the suction portion 10a to an oil seal 39 (FIG. 1) for sealing the lower portion of the pump shaft 10. A relief passage 24d is opened in the discharge part 10b. The seal insertion groove 24i is formed to divide the periphery of the return passage 24g, the periphery of the suction portion 10a and the discharge portion 10b, the periphery of the plunger insertion hole 24a, and the periphery of the contact surface 24h of the lower end of the timer piston 34. ing. The holes, grooves, and the like formed on the upper surface of the main body case 24 are concentrated on 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.
[0025]
In the pump case 25 into which the distribution shaft 11 is inserted, a distribution shaft insertion hole 25e is opened in parallel with the plunger insertion hole 25f and the piston hole 25b in the vertical direction and with the same diameter, and the piston holes formed in the pump case 25 are formed. 25b, the distribution shaft insertion hole 25e, the plunger insertion 25f, the fuel gallery hole 25a, the communication hole, and the like are all round holes so that they can be easily processed. .. Are distributed radially in the pump case 25 at the upper part of the distribution shaft 11 and communicated with discharge joints 41, 41,. The fuel can be sent to the injection nozzle from the joints 41.
[0026]
As shown in FIGS. 17 and 18, the distribution shaft 11 communicates with the distribution passage 25g and the fuel passage 25d for sending the fuel discharged from the plunger 6, as shown in FIGS. An annular groove 11a is formed, and a slit 11b is formed in parallel with the axial center from the annular groove 11a. The slit 11b forms a single vertical groove 11c that communicates with the annular groove 11a. A corner portion that is an intersection point with the outer periphery of the distribution shaft is cut by a plane parallel to the axis to form a plane processing portion 11d.
With this configuration, when the distribution shaft 11 is rotated, if there is a corner, galling occurs. However, since the planar processing portion 11d is provided, the portion becomes obtuse and galling does not occur. In addition, the supply period from the slit to the distribution passage 25g can be extended.
[0027]
With the configuration described above, 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 into the fuel gallery hole 25a. At the same time, the plunger 6 is reciprocated. Then, the pressure is fed from the delivery valve 37 to the distribution shaft 11 through the fuel passage 25d, and intermittently sent to the distribution passages 25g, 25g... By the rotation of the distribution shaft 11, and from the discharge joint 41 to the injection nozzle. Fuel is sent. The engine speed is increased, the rack 16 is slid by the governor mechanism, the control sleeve 17 is rotated to adjust the amount of fuel discharged by the plunger 6, and the fuel pump 10 is discharged from the oil pump 10 as the speed increases. The pressure of the fuel to be increased also rises and lowers the timer piston 34 to rotate the timer lever 32 and raises and lowers the control sleeve 31 to adjust the pressure feeding timing.
[0028]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
That is, since the plunger drive mechanism and the distribution shaft drive mechanism are vertically oriented, the hydraulic head incorporating the plunger fuel metering mechanism and the fuel distribution mechanism from the upper surface of the main body case, respectively. Can be easily assembled from above and can be easily disassembled.
[0029]
Since it is configured as in claim 2, the locking piece mounted on the rack enters the insertion hole, and the hydraulic head sub mechanism is assembled on the upper surface, so that it can be easily disassembled and assembled, and the processing of the main body case is also easy To be able to.
[0030]
Since it is configured as in claim 3, the fuel on the pump case side is not leaked to the main body case side by the seal member, the system oil on the main body case side is not leaked to the pump case side, oil tightness is improved, and each is lubricated, The fuel injection pressure can be increased.
[0031]
Since it comprised like Claim 4, the plunger assembly which integrated the plunger, the control sleeve 17, and each upper and lower spring receiver integrally can be fixed to a pump case with a spring receiving member, and it can be easily assembled in a pump case, It can be easily assembled into the main unit 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 the main part of the same.
FIG. 4 is a front sectional view showing a state in which a hydraulic head is removed.
FIG. 5 is a sectional side view of the same.
FIG. 6 is an exploded perspective view of a fuel injection pump.
7 is a cross-sectional view showing a state where the plunger assembly of the hydraulic head sub mechanism 2 is inserted into the main body case 24. FIG.
FIG. 8 is also a cross-sectional view in the middle of locking.
FIG. 9 is a cross-sectional view of the same when engaged.
FIG. 10 is a cross-sectional plan 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.
14 is a cross-sectional view of an embodiment in which an oil feed pump is disposed across both a main body case 24 and a pump case 25. FIG.
FIG. 15 is a cross-sectional view of an embodiment in which an oil feed pump is disposed in a main body case 24 below a mating surface.
FIG. 16 is a plan view showing an upper surface of the main body case.
FIG. 17 is a side sectional view of a distribution shaft.
18 is a cross-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 structure 4 Cam shaft 6 Plunger 9 Pump shaft 10 Oil supply pump 11 Distribution shaft 17 Control sleeve 24 Main body case 25 Pump case 25d Fuel passage

Claims (4)

In a distribution type fuel injection pump that distributes and supplies fuel to be pumped from one plunger 6 to a fuel injection nozzle arranged for each of a plurality of combustion chambers of an internal combustion engine,
A cam shaft 4 having a cam for reciprocating the plunger 6, the interlockingly connected to the cam shaft 4 in an orthogonal direction, and a pump shaft 9 which drives the oil transfer pump 10, and disposed in the main body case 24 Main body case sub-structure 1 is configured,
The distribution shaft 11 provided with a slit 11b intermittently cut off from the top of the plunger 6 through the fuel passage 25d and the plunger 6 are disposed in the pump case 25 so that the hydraulic head sub mechanism 2 is provided. Configure
The hydraulic head sub mechanism 2 is placed on the main body case sub mechanism 1, and the governor mechanism 3 is attached to the side of the main body case sub mechanism 1.
The oil pump 10 driven by the pump shaft 9 is disposed on the mating surface of the main body case 24 and the pump case 25 at the upper part of the pump shaft 9, and fuel is supplied from the fuel tank by the oil pump 10. Supplied to the suction plunger 6,
Further , the fuel injection pump is characterized in that the distribution shaft 11 is disposed on an extension of the pump shaft 9 and the pump shaft 9 and the distribution shaft 11 are connected . A fuel injection pump according to claim 1, the upper surface of the main body case 24 includes an insertion hole of the fuel metering member which rotates the plunger in conjunction with the governor mechanism 3, and the insertion hole of the pump shaft 9, the A fuel injection pump comprising a suction portion 10a for the oil feed pump 10 and a hydraulic head sub mechanism 2 joined to the upper surface thereof in a separable manner. 2. The fuel injection pump according to claim 1, wherein when the pump case 25 constituting the hydraulic head sub mechanism 2 and the main body case 24 constituting the main body case sub mechanism 1 are coupled, the pump case 25 and the main body case 24 are connected. Is separated through a seal member, fuel oil is supplied to the former, and the latter is lubricated with system oil.   2. The fuel injection pump according to claim 1, wherein the plunger 6, 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 hydraulic head sub mechanism 2. A fuel injection pump comprising a three-dimensional structure, wherein the plunger assembly is inserted into a plunger insertion hole opened in the main body case 24 from above, and the pump case 25 and the main body case 24 are assembled together.

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