JPH0526273Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a distribution type fuel injection pump used in internal combustion engines such as diesel engines.

(Prior art and its problems) Conventionally, as shown in FIG.
A distribution type fuel injection pump 6 is known which is equipped with a hydraulic timer 5 that is operated by fuel oil pressure supplied through a hydraulic timer 5 to adjust fuel injection timing.

In such a conventional distribution type fuel injection pump 6, fuel that flows in from an inlet 7 provided in the pump housing 1 is pressurized by the feed pump 2, and then adjusted to a predetermined pressure related to the rotation of the engine by the regulating valve 8. After the pressure is regulated, the oil passage hole 10 on the upper end side of the feed pump ring 9 and the oil passage hole 12 of the feed pump cover 11 that communicates with the oil passage hole 10 (these oil passage holes 10 and 12 It flows into the upper part of the inside of the pump chamber 3 (on the opposite side from the hydraulic timer 5) through a supply path 4 (forming a supply path 4). Therefore, the fuel oil pumped from the feed pump 2 flows into the upper part of the pump chamber 3 and is stirred, and then introduced into the fuel oil inlet of the hydraulic timer 5.

This hydraulic timer 5 rotates a roller holder 16 via a connecting rod 15 by a timer piston 14 that slides inside a cylinder 13 depending on the balance between fuel oil pressure introduced from a pump chamber 3 and the spring force of a timer spring. The roller holder 16 is configured so that the injection timing can be adjusted by moving the roller holder 16.
In a hydraulic timer equipped with a servo valve mechanism that prevents the timer piston 14 from moving in the direction of delaying the injection timing due to the reaction force of When the oil flows in and the engine speed decreases, the fuel oil in the high pressure chamber flows to the fuel tank side via the servo valve mechanism, so dirt easily flows into the servo valve mechanism, which is the least likely to get clogged with dirt. If there is dust such as cutting debris in the chamber 3, there is a problem that if the dust clogs the servo valve mechanism, it will become inoperable.

(Purpose of the invention) The present invention was made in view of the above circumstances, and its purpose is to prevent dust from flowing into the hydraulic timer section.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a fuel supply path from the feed pump to the pump chamber in a position close to the hydraulic timer, and supplies the fuel oil pressure from the supply path. The present invention provides a distribution type fuel injection pump characterized in that the fuel is supplied to the hydraulic timer via the pump chamber.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 7. 20 in FIG. 1 is a distribution type fuel injection pump of the present invention, and its pump housing 21
A plunger 23 is slidably fitted into a plunger barrel 22 provided within the plunger barrel 22.
A cam disk 24 is provided at one end of the pump 3, and a pump drive shaft 25 is connected to the cam disk 24. A roller holder 27 holding a plurality of rollers 26 concentrically with the pump drive shaft 25 is provided within the pump housing 21 . The cam disk 24 is attached to the roller 26 of this roller holder 27.
The cam surface 24 a of the plunger 23 is pressed by the biasing force of the plunger spring 28 . Therefore, the plunger 23 is reciprocated in the axial direction as the pump drive shaft 25 rotates, and The fuel in the pump chamber 29 is sucked and pressurized, and the fuel is distributed under pressure into each cylinder of the multi-cylinder internal combustion engine via the delivery valve 30.

A hydraulic timer 31 is provided at the lower part of the pump housing 21, and the timer 31 is operated by the fuel oil pressure in the pump chamber 29, and the timer 31 is operated by the fuel oil pressure introduced from the pump chamber 29 and the spring force of the timer spring. The roller holder 27 is rotated via a connecting rod 34 by a timer piston 33 that slides within the cylinder 32 due to balance, thereby adjusting the injection timing.
On the other hand, the fuel in the fuel tank is pumped by a fuel pump, filtered by a filter, and then flows into the inflow passage 36a from the fuel inlet 35 provided in the pump housing 21, and the fuel in the fuel tank is pumped by the fuel pump provided in the pump housing 21. After being further pressurized by the feed pump 37 driven by the shaft 25 in relation to the rotational speed of the engine and adjusted to a predetermined pressure in relation to the rotation of the engine by the regulating valve 38, the position near the hydraulic timer 31 is It is designed to be supplied to the lower part of the inside of the pump chamber 29 through a supply path 39 provided in the pump chamber 29 . As shown in FIGS. 2 and 3, the supply path 39 includes an annular groove 41 provided all around the outer periphery of one side of the feed pump ring 40 (the surface on the roller holder 27 side), and A through hole 42 is provided on the upper side of the pump ring 40 to communicate with the discharge passage 36b and the annular groove 41, and a through hole 42 is provided on the lower side of the feed pump cover 43 as shown in FIGS. 4 and 5. It consists of an arcuate notch 44 provided over a predetermined angular range, and an arcuate notch 45 provided on the lower peripheral edge of the roller holder 27 over a predetermined angular range, as shown in FIGS. 6 and 7. Between the lower inner peripheral surface 21a of the pump housing 21 (bottom surface of the pump chamber 29) and the lower surface of the annular groove 41, and between the arcuate notches 44 and 45 on the lower inner surface of the pump housing 21, A gap is formed between each of them so that they communicate with each other. One end side (cam disc 24 side) of the arc-shaped notch 45 of the roller holder 27 is located close to above the fuel oil inlet 46 of the hydraulic timer 31.

(Function) Fuel inlet 35 provided in the pump housing 21
Flows into the inflow path 36a from the feed pump 3.
7 pressurizes the regulating valve 3.
The fuel oil adjusted to a predetermined pressure by 8 passes sequentially through the through hole 42 of the feed pump ring 40 → the annular groove 41 → the notch 44 of the feed pump cover 43 → the notch 45 of the roller holder 27 and reaches the bottom of the pump chamber 29. After flowing into the side, a part of it flows into the hydraulic timer 31.
The fuel oil is introduced into the fuel oil inlet 46 of the fuel oil.

Here, even if there is debris such as cutting debris in the temporary pump chamber 29, fuel oil is introduced almost directly from the notch 45 of the roller holder 27 to the fuel oil inlet 46 of the hydraulic timer 31. , there is no risk of dirt flowing into the hydraulic timer 31, and therefore,
The hydraulic timer will not become inoperable due to dirt clogging.

(Effects of the invention) As detailed above, the distribution type fuel injection pump of the invention has a fuel supply path from the feed pump to the pump chamber in a position close to the hydraulic timer, and the fuel oil pressure is supplied from the supply path to the pump chamber. Since the hydraulic timer is supplied through the pump, even if there is dust in the temporary pump chamber, the dust can be prevented from flowing into the hydraulic timer section, and the hydraulic timer can be prevented from becoming inoperable due to dust clogging. It is possible.
In addition, since the fuel pressure pumped by the feed pump flows into the pump chamber from the supply path and is then supplied to the hydraulic chamber timer, the pulsation of the feed pump, which is generally a vane pump that generates pulsation, acts directly on the hydraulic timer. Therefore, there is no adverse effect on the timer operation of the hydraulic timer.

[Brief explanation of drawings]

1 to 7 show an embodiment of the present invention,
Figure 1 is a longitudinal sectional view of the distribution type fuel injection pump, Figure 2 is a longitudinal sectional view of the distribution type fuel injection pump.
The figure is a front view of the feed pump ring, Figure 3 is a vertical sectional view taken along the - line in Figure 2, Figure 4 is a front view of the feed pump cover, and Figure 5 is a - line in Figure 4.
6 is a front view of the roller holder, FIG. 7 is a vertical sectional view taken along the - line in FIG. 6, and FIG. 8 is a vertical sectional view of a conventional distribution type fuel injection pump. . 20... Distribution type fuel injection pump, 21... Pump housing, 31... Hydraulic timer, 37...
Feed pump, 39... supply path.

Claims (1)

[Scope of utility model registration request] A distribution device comprising a hydraulic timer that adjusts the timing of fuel injection by being operated by the hydraulic pressure of fuel that is pressure-fed by a feed pump provided in the pump housing and supplied to the pump chamber in the pump housing via a supply path. type fuel injection pump, characterized in that the supply passage is provided in a position close to the hydraulic timer, and the fuel oil pressure is supplied from the supply passage to the hydraulic timer via the pump chamber. type fuel injection pump.