JP3967782B2 - Isobaric valve for fuel injection pump - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an isobaric valve structure including a delivery valve and a return valve in a fuel injection pump that supplies high-pressure fuel to a fuel injection valve of a diesel engine.
[0002]
[Prior art]
Conventionally, a technology related to an isobaric valve of a fuel injection pump constituted by a delivery valve and a return valve is known. For example, the techniques described in Japanese Utility Model Laid-Open Nos. 63-19068, 62-243965, 3-19465, and 6-213105 are used. In these conventional fuel injection pumps, it is difficult to assemble the delivery valve and the return valve in a small and compact manner so as to obtain a good sealing performance in a narrow valve casing, and there is a limit to increasing the pressure of fuel injection.
[0003]
In the technique described in Japanese Utility Model Laid-Open No. 63-19068, an isobaric valve for a diesel engine fuel injection pump having a fuel injection delivery valve and a fuel suction return valve, the return valve is connected to the shaft of the delivery valve. It is housed in a bottomed inner hole provided at the center. Further, the bottomed inner hole communicates with the compression space portion by the delivery valve fuel passage and the plunger through a small hole in the bottomed inner hole shaft portion. A fuel discharge hole for communicating the compression space and the fuel passage is provided around the return valve, and is opened to the central portion of the valve spring for the delivery valve.
However, in Japanese Utility Model Laid-Open No. 63-19068, the seat is a bottom-contacting system, and the seal area is large and it is difficult to obtain a high contact pressure seal. In addition, it is necessary to polish the periphery of the delivery valve at the same time as the seat. There is. In addition, there is a problem that it is difficult to fix the return valve portion in the delivery valve, and high pressure sealing is difficult.
[0004]
In Japanese Patent Application Laid-Open No. 62-243965, a return valve having a configuration in which a communication passage communicating between the upstream and the downstream is formed in a delivery valve, and the check valve is pressed by a check valve spring to close the communication passage. The spring receiver of the cap with which one end of the delivery valve spring engages is formed in front of the tip of the check valve spring, that is, on the side of the check valve. The diameter and the diameter of the check valve spring can be enlarged. Therefore, in this example as well, it is difficult to obtain a high-pressure seal by making it compact and compact.
[0005]
In Japanese Utility Model Laid-Open No. 3-19465, the delivery valve is provided with a cylindrical portion for forming a return valve accommodating chamber, and a holder having a return valve seat portion is formed with a cylindrical skirt portion. A return valve spring that press-fits the valve body and biases the valve body is positioned inside the skirt portion.
[0006]
In the technique described in JP-A-6-213105, a delivery valve and a return valve are built in the plunger barrel, and the seat is flat, but it is configured at the bottom of a deep hole and is difficult to polish. is there. The return valve outer diameter guides the return valve itself and the delivery valve. The return valve seat and the delivery valve periphery must be polished coaxially with the seat. It was difficult.
[0007]
Further, the isobaric valve of the fuel injection pump shown in FIGS. 14 and 15 is also known. However, in the case of the prior art, the delivery valve mechanism D and the return valve mechanism R are arranged in parallel, and the high-pressure seal portion is configured indefinitely, making it difficult to process this portion. . Also, since the delivery valve and return valve seats are not on the same axis, it is difficult to polish the seat surface of the seat. Further, the high pressure pressure receiving diameter is left and right unbalanced, and the load generated by the high pressure during injection causes unbalance with respect to the tightening surface, and the high pressure fuel oil is likely to leak.
In addition, the parallel type requires a larger diameter in the delivery valve holder and cannot be miniaturized.
[0008]
Further, in the prior art of the series arrangement type of the delivery valve mechanism D and the return valve mechanism R shown in FIG. 16, the delivery valve chamber and the return valve chamber are stacked in series, so that the height of the delivery valve holder becomes large. The fuel injection pump cannot be downsized.
[0009]
[Problems to be solved by the invention]
In the present invention, a delivery valve 1 is guided at a relatively large interval on the outer periphery of a return valve 2 constituted by a ball valve or a conical valve, and the delivery valve 1 is pressed against a seat portion.
Further, the lower surface of the delivery valve 1 is configured as a flat sheet, and is configured so as to be loosely fitted, so that polishing of the sheet surface is facilitated.
The return valve portion is built in the delivery valve, but is not integrated and does not require a structure for fixing the return valve portion.
With this configuration, the processability of the isobaric valve of the fuel injection pump can be improved, and the size and cost can be reduced.
In addition, the fuel supply performance can be stabilized and the combustion performance of the diesel engine can be stabilized.
[0010]
[Means for Solving the Problems]
The problems to be solved by the invention are as described above. Next, means for solving the problems will be described.
A delivery valve 1 having a flat seat surface at the lower part, a throttle hole 3 for the return valve 2 at the upper part, and a seat for arranging the return valve 2 inside is arranged in the cylindrical hole of the valve casing 11 and guided. A lift stopper 10 that constitutes the lift restricting structure of the delivery valve 1 is formed on the upper portion of the guide portion, and a delivery valve spring 5 that presses the delivery valve 1 is arranged on the upper portion of the delivery valve 1, and the delivery valve 1 is disposed inside. The valve casing 11 arranged in the above is placed on the upper surface of the delivery valve seat 12 or the dead end type plunger barrel 17 not provided with the delivery valve seat 12, and the respective components are arranged on the same axis. In the isobaric valve of the fuel injection pump, the upper end surface of the delivery valve seat 12, The upper end surface of the plunger barrel 17 of the dead end type, formed a deli Beri valve seat surface S of the annular Deriberibarubu 1, an annular high-pressure seal surface 26a of the valve casing 11, a return valve spring for pressing the return valve 2 8 is disposed in a hole in the upper part of the delivery valve seat 12 or the dead end type plunger barrel 17 where the delivery valve seat 12 is not provided, and constitutes a high pressure fuel passage in the guide portion of the valve casing 11 ; The high-pressure fuel passage is constituted by a hole 9 on the side surface of the lift stopper 10 .
[0011]
[Action]
Next, the operation will be described.
The polishing of the high-pressure seal surface 26 on the upper surface of the valve seat 12 has a delivery valve mechanism and a return valve mechanism configured on the same axis, so that centering at the time of processing can be easily performed, thereby reducing processing costs. In addition, it is possible to reduce the size and size of the isobaric valve of the fuel injection pump.
The delivery valve 1 can be easily processed, and downsizing and cost reduction can be achieved. The fuel high-pressure passage, by forming a hole 9 of the lift stopper side, it is possible to configure a high-pressure fuel passage portion of the lift stopper 10 with a simple processing.
[0012]
【Example】
Next, examples will be described.
Figure 1 is a side sectional view of the equal-pressure valve of a fuel injection pump provided with the Deriberibarubu and return valve of the reference example, FIG. 2 is also a side sectional view of a portion of the valve casing 11 and the valve seat 12 of the reference example, FIG. 3 reference example V-V arrow view showing the high pressure sealing face of FIG. 2 is, W-W arrow view of FIG. 2 and FIG. 4 is a likewise reference example, X-X arrows in FIG. 2 and FIG. 5 is a similarly reference example FIG. 6 is a side sectional view of an embodiment showing a configuration in which a plunger barrel 17 is also used as a valve seat instead of the valve seat 12, and FIG. 7 is a view of a lift stopper side hole 9 constituting a lift restricting structure of the delivery valve. FIG . 8 is a plan view of the embodiment in which the high-pressure fuel passage is constituted by the hole (9) on the side of the lift stopper constituting the lift restricting structure of the delivery valve.
[0013]
FIG. 9 is a side sectional view of a reference example in which the high pressure fuel passage 13 is configured with the outer peripheral two surfaces of the delivery valve 1 as the cut surface 13, and FIG. 10 is a plan view of the reference example in which the cut surface 13 is also used as the high pressure fuel passage. 11 is a side sectional view showing an oil passage of a reference example constituted by a hole 9 on the side surface of the lift stopper and a cut surface 18 of the return valve 2. FIG. 12 is a side view of the hole 9 on the side surface of the lift stopper of FIG. plan view of a reference example of a portion of the cut surface 18, FIG. 13 is a side sectional view showing a reference example bored high-pressure fuel passage 25 to Deriberibarubu 1, FIG. 14, a conventional Deriberibarubu mechanism D and a return valve mechanism R a side cross-sectional view showing a structure arranged in parallel on the left and right, Figure 15 is a plan view of a prior art of a portion of the valve seat 12 of FIG. 14, FIG. 16 Deriberibarubu mechanism D and the return Bal A mechanism R in the vertical is a side sectional view showing a prior art series arrangement.
[0014]
In the reference example of FIG. 1, a valve seat 12 is separately interposed between the delivery valve 1 and the plunger barrel 17 to constitute an isobaric valve of a fuel injection pump including a delivery valve mechanism and a return valve mechanism. A plunger 16 constituting a fuel injection pump is fitted inside the plunger barrel 17 so as to be movable up and down. The upper surface of the valve seat 12 is configured as the seat surface of the delivery valve 1. Further, a guide portion of the return valve spring 8 is formed inside the valve seat 12, and the return valve stopper 7 is fitted on the bottom surface of the return valve spring 8. The return valve stopper 7 also serves as a spring receiver for the return valve spring 8.
[0015]
In the reference example of FIG. 1, a guide hole of the delivery valve 1 is provided inside the valve casing 11 , and the delivery valve 1 is disposed in the guide hole so as to be movable up and down. A delivery valve spring 5 is in contact with the upper surface of the delivery valve 1, and the upper part of the delivery valve spring 5 is received by a delivery valve spring receiver 4. Further, the lift stopper 10 of the delivery valve 1 may be configured on the outer periphery of the delivery valve 1 as shown in FIG.
[0016]
In addition, a return valve throttle hole 3 of the return valve mechanism is formed in the center of the delivery valve 1. A seat portion of the return valve 2 is formed inside the delivery valve 1. In FIG. 1, the return valve 2 is a ball valve. A return valve guide 6 is in contact with the lower surface of the return valve 2. The return valve guide 6 also serves as a spring receiver above the return valve spring 8. L1 is the lift stroke of the delivery valve 1, and L2 is the lift stroke of the return valve 2.
[0017]
In the embodiment of FIG. 6, the delivery valve mechanism and the return valve mechanism have substantially the same configuration, but the valve seat 12 is not provided, and the delivery valve seat surface S is directly attached to the upper surface of the plunger barrel 17. An embodiment in which the plunger barrel 17 is provided with a fitting hole for the return valve spring 8 is shown.
[0018]
FIG. 2 is a drawing in which only the valve casing 11 and the valve seat 12 are taken out from the reference example of FIG. 1, and FIG. 3 illustrates the high-pressure sealing surface of the delivery valve 1.
That is, the annular high pressure seal surface 26 a shown by the shade in FIG. 3 is the high pressure seal surface between the valve casing 11 and the valve seat 12.
Further, the delivery valve 1 comes into contact with the annular delivery valve seat surface S from above to perform high-pressure sealing. That is, the upper surface of the valve seat 12 is precisely finished, and the high pressure seal surface 26 is constituted by an annular high pressure seal surface 26a and an annular delivery valve seat surface S.
The high-pressure seal surface 26 includes an annular high-pressure seal surface 26a between the outer shoulder end 12a and the inner shoulder end 12b, and an annular delivery valve seat surface S.
[0019]
In reference example of FIG. 4 and FIG. 5, the knock pin 15, 15 for joining the valve casing 11 and the valve seat 12, it illustrates the position of the high-pressure sealing surface fastening bolts 14, 14. The knock pins 15 and 15 are shifted from the high pressure seal surface 26 and are on the circumference between the high pressure seal surface 26 and the delivery valve seat surface S. On the contrary, the high-pressure seal surface fastening bolts 14 and 14 screwed to bring the valve casing 11 and the valve seat 12 into close contact with each other for high-pressure sealing are tightened to the high-pressure seal surface 26 so as to be tightened. 26 is arranged overlapping with H.26.
[0020]
In the embodiment of FIGS. 7 and 8, the Deriberibarubu 1 provided with the flat sheet surface at the bottom it is provided with a throttle hole 3 of the return valve at the top. In addition, the seat surface of the return valve 2 is formed inside the delivery valve 1.
The delivery valve 1 is guided in a cylindrical hole in the valve casing 11 , and a fuel high-pressure passage is formed in the guide portion. The fuel high-pressure passage uses a hole 9 on the side surface of the lift stopper constituting the lift restricting structure of the delivery valve and a gap between the lift stopper 10 formed between the delivery valve 1 and the outer periphery of the guide hole. The hole 9 on the side surface of the lift stopper constitutes a high-pressure fuel passage, but is composed of four holes deeper than the depth of the lift stopper 10 provided in the guide portion.
[0021]
Further, a lift restricting structure is formed in the upper part of the guide part or the delivery valve, the delivery valve spring 5 is arranged in the upper part of the delivery valve 1, the return valve 2 constructed as a ball valve is arranged in the delivery valve 1, and the return valve spring 8 is arranged in the hole of the valve seat 12 or the dead end type plunger barrel 17, and each component is arranged on the same axis. The delivery valve seat surface S of the delivery valve is the upper end surface of the valve seat 12 or the upper end surface of the dead end type plunger barrel 17.
[0022]
Oite the reference example of FIG. 9 and FIG. 10, the outer periphery of Deriberibarubu 1, the cut surface 13 of the second surface is provided, and a portion of the cut surface 13 is configured to high-pressure fuel passage. Other configurations are substantially the same. The return valve stopper 7 is formed with a hole Dr larger than the fuel high-pressure passage hole diameter Dp on the plunger barrel 17 side in the center, and the return valve stopper 7 fluctuates due to a pressure imbalance caused by a difference in flow of high-pressure fuel. It is configured to suppress the decrease.
[0023]
In the reference examples of FIGS. 11 and 12, the high-pressure fuel passage on the outer periphery of the delivery valve 1 is constituted by four holes 9 on the side surfaces of the lift stopper. The return valve 2 is configured as a conical type valve, and the three outer circumferential surfaces of the conical type return valve 2 are configured as cut surfaces 18 and configured as a return oil passage. At this time, the lower surface of the return valve 2 is applied to the delivery sheet to serve as a stopper.
[0024]
In FIG. 13, the fuel high-pressure passage is formed by the hole 9 on the side surface of the lift stopper, and the delivery valve 1 is further extended upward, and the fuel high-pressure passage 25 is formed in the extended portion.
[0025]
【The invention's effect】
In the present invention, the delivery valve 1 having a flat seat surface at the bottom, a throttle hole 3 for the return valve 2 at the top, and a seat for placing the return valve 2 inside is disposed in the cylindrical hole of the valve casing 11 and guided. A lift stopper 10 constituting a lift restricting structure of the delivery valve 1 is formed on the upper part of the guide portion of the cylindrical hole, and a delivery valve spring 5 for pressing the delivery valve 1 is arranged on the upper part of the delivery valve 1, The valve casing 11 in which the delivery valve 1 is arranged is placed on the upper surface of the delivery valve seat 12 or the dead end type plunger barrel 17 where the delivery valve seat 12 is not provided, and each component is placed on the same axis. In the isobaric valve of the fuel injection pump having the configuration arranged in FIG. The end surface, or the upper end surface of the dead-end type of plunger barrel 17, and constitute a deli Beri valve seat surface S of the annular Deriberibarubu 1, an annular high-pressure seal surface 26a of the valve casing 11, for pressing the return valve 2 The return valve spring 8 is arranged in a hole in the upper part of the delivery valve seat 12 or the dead end type plunger barrel 17 where the delivery valve seat 12 is not provided, and a high pressure fuel passage is provided in the guide portion of the valve casing 11. Since the high-pressure fuel passage is configured by the hole 9 on the side surface of the lift stopper 10 , the following effects can be obtained.
First, in the technology described in Japanese Patent Application Laid-Open No. 6-213105, which is a conventional technology, a delivery valve and a return valve are built in the plunger barrel, and the seat is flat, but is constructed at the bottom of a deep hole. It was difficult to polish. The return valve outer diameter guides the return valve itself and the delivery valve. The return valve seat and the delivery valve periphery must be polished coaxially with the seat. It was difficult.
Such a point could be improved.
[0026]
Secondly, the isobaric valve of the fuel injection pump shown in FIGS. However, in the case of the prior art, the delivery valve mechanism D and the return valve mechanism R are arranged in parallel, and the high-pressure seal portion is configured indefinitely, making it difficult to process this portion. . Also, since the delivery valve and return valve seats are not on the same axis, it is difficult to polish the seat surface of the seat. In addition, the high pressure receiving diameter is left and right unbalanced, and the load generated by the high pressure during injection causes unbalance to the tightening surface, which causes the high pressure fuel oil to easily leak.
The present invention was able to solve this problem.
[0027]
Third, the fuel high-pressure passage, by forming a hole 9 of the lift stopper side, a large amount of fuel injection can be a compact size by increasing a fuel pressure passage portion of the lift stopper 10 with a simple process It is.
[Brief description of the drawings]
FIG. 1 is a side sectional view of an isobaric valve of a fuel injection pump including a delivery valve and a return valve of a reference example .
FIG. 2 is a side cross-sectional view of a valve casing 11 and a valve seat 12 of a reference example .
3 is a VV arrow view showing the high-pressure seal surface of FIG. 2 as a reference example .
4 is a view taken along the line WW in FIG. 2 which is also a reference example . FIG.
FIG. 5 is a view taken along the line XX of FIG. 2 which is also a reference example .
6 is a side sectional view of an embodiment showing a configuration in which a plunger barrel 17 is also used as a valve seat instead of the valve seat 12. FIG. 7 shows a high-pressure fuel by a hole 9 on a side of a lift stopper constituting a lift restricting structure of the delivery valve. Side surface sectional drawing of the Example which comprised the channel | path.
FIG. 8 is a plan view of an embodiment in which a high-pressure fuel passage is configured by a hole (9) on a side surface of a lift stopper that constitutes a lift restricting structure of a delivery valve.
FIG. 9 is a side cross-sectional view of a reference example in which a high pressure fuel passage 13 is configured with two outer peripheral surfaces of the delivery valve 1 as cut surfaces 13;
FIG. 10 is a plan view of a reference example in which the cut surface 13 is similarly a high pressure fuel passage.
11 is a side sectional view showing an oil passage of a reference example constituted by a hole 9 on a side surface of the lift stopper and a cut surface 18 of the return valve 2. FIG.
12 is a plan view of a reference example showing the hole 9 on the side surface of the lift stopper and the cut surface 18 of the return valve 2 in FIG.
13 is a side cross-sectional view showing a reference example in which a high pressure fuel passage 25 is formed in the delivery valve 1. FIG.
FIG. 14 is a side sectional view showing a configuration in which a conventional delivery valve mechanism D and a return valve mechanism R are arranged in parallel on the left and right.
15 is a plan view showing a portion of the valve seat 12 of FIG.
FIG. 16 is a side cross-sectional view showing a conventional technique in which a delivery valve mechanism D and a return valve mechanism R are vertically arranged in series.
[Explanation of symbols]
D Delivery valve mechanism R Return valve mechanism 1 Delivery valve 2 Return valve 3 Return valve throttle hole 9 Lift stopper side hole 10 Lift stopper 13 Cut surface

Claims (1)

In the cylindrical hole of the valve casing (11 ), the flat seat surface is formed in the lower part, the throttle hole (3) of the return valve (2) in the upper part, and the delivery valve (1) comprising the seat in which the return valve (2) is arranged. To guide and
A lift stopper (10 ) constituting a lift restricting structure of the delivery valve (1) is formed on the upper part of the guide portion of the cylindrical hole, and a delivery valve spring (5) for pressing the delivery valve (1) is attached to the delivery valve ( 1) is placed on top of
The valve casing 11 in which the delivery valve (1) is disposed is placed on the upper surface of the delivery valve seat (12) or a dead end type plunger barrel (17) not provided with the delivery valve seat (12). In the isobaric valve of the fuel injection pump having a configuration in which each component is arranged on the same axis,
On the upper end surface of the delivery valve seat (12) or the upper end surface of the dead end type plunger barrel (17), the annular delivery valve seat surface (S) of the delivery valve (1) and the valve casing (11) Forming an annular high pressure sealing surface (26a);
The return valve spring (8) for pressing the return valve (2) is a hole in the upper part of the delivery valve seat (12) or the dead end type plunger barrel (17) not provided with the delivery valve seat (12). Placed in the
A high pressure fuel passage is formed in a guide portion of the valve casing (11) , and the high pressure fuel passage is formed by a hole (9) on a side surface of the lift stopper (10) .

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