JPS62240471A - Pulser for detecting timing - Google Patents

Abstract

PURPOSE:To correctly detect the operation timing of a distribution type fuel injection pump free from the influence of abrasion of a various sorts of constitution parts and working precision by forming the uneven parts for detecting revolution onto the outer peripheral surface of a cam disc. CONSTITUTION:In a distribution type fuel injection pump 1, a plunger 4 is revolved in reciprocation by the cooperative action of a roller holder 7 and a cam disc 6 revolved by a riving shaft 5, and the fuel in a high pressure chamber 8 is pressurized. The pressurized fuel is sent under pressure into a delivery valve 9 in a prescribed timing, and jetted by the quantity corresponding to the position of a control sleeve 10. With such constitution, a plurality of holes 61-63 are formed at a prescribed angular intervals onto the outer peripheral surface of the cam disc 6 so that the pump acts as a pulser for obtaining the signal related to the operation timing of the plunger 4. A pick-up coil 11 is arranged oppositely in the vicinity of the cam disc 6.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a timing detection pulser for a rotation timing detection device that can accurately detect the operation timing of a distributed fuel injection pump.

(Prior Art) In a distribution type fuel injection pump, a configuration in which the fuel injection amount and/or injection timing, etc. are electronically controlled is known. If so, it is necessary to electrically detect the operating timing of the fuel injection pump. For this reason, conventionally, as shown in, for example, Japanese Patent Laid-Open No. 60-125756, a pulsar is attached to the drive shaft of a distribution type fuel injection pump, and a pickup coil is disposed near the pulsar.
A configuration in which the timing at which a cog provided in a pulser faces a pickup coil is electrically detected is widely used.

(Problem to be Solved by the Invention) However, when detecting the operating timing of the fuel injection pump using a pulser attached to the drive shaft of the distribution type fuel injection pump, the accuracy of the detection timing is different from that of the drive shaft. This method solves the problem that it is difficult to accurately detect the operating timing of the fuel injection pump over a long period of time because it depends on mechanical wear and/or machining accuracy of the coupling provided between the roller holder and the coupling. have.

An object of the present invention is to accurately detect the operation timing of a distribution type fuel injection pump over a long period of time, regardless of the wear and/or machining accuracy of various mechanical parts interposed between the drive shaft and the plunger. An object of the present invention is to provide a balsa for timing detection that makes it possible to do this.

(Means for Solving the Problems) To achieve the above object, the present invention provides a timing detection pulser for detecting the operation timing of a distribution type fuel injection pump. The device is characterized in that a detection unevenness is provided and the desired timing is detected using the unevenness.

(Function) Since the cam disc is used as a pulser for timing detection by providing irregularities on the outer circumferential surface of the cam disc, the fuel injection pump can be easily operated regardless of the accuracy and wear of the mechanical parts between the drive shaft and the plunger. It becomes possible to accurately detect the required actuation timing.

(Example) Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

FIG. 1 shows an embodiment of a distribution type fuel injection pump to which a timing detection pulser according to the present invention is applied. The distribution fuel injection pump 1 includes a plunger barrel 3 fixed to a housing 2, and a plunger 4 fitted into the plunger barrel 3 so as to be movable in the axial direction.The plunger 4 is not shown. Due to the cooperative action of a cam disk 6 rotated by a drive shaft 5 driven by an internal combustion engine and a roller holder 7, the plunger 4 performs a rotational reciprocating motion according to the rotation of the drive shaft 5. High pressure chamber 8
The fuel sucked into the tank is pressurized.

This pressurized fuel is fed under pressure to the delivery pulp 9 at a predetermined timing, and is injected in an amount corresponding to the position of the control sleeve 1o fitted into the plunger 4.

The above-mentioned fuel suction and fuel pumping operations performed by the reciprocating rotation of the plunger 4 are the same as in the case of a conventional distribution type fuel injection pump, so a detailed explanation thereof will be omitted here. .

In order to obtain a signal related to the actuation timing of the distribution fuel injection pump 1, that is to say the actuation timing of the plunger 4, the cam disk 6 has holes 61. 6□, 6
:1. ... are formed, and a pickup coil 11 is arranged near the cam disk 6 to face it. As can be seen from FIG. 1, the holes 63.6□, ... arranged on the outer peripheral surface of the cam disc 6 are arranged at equal angular intervals along the cam profile of the cam disc 6. On the other hand, the pickup coil 11 is fixed to a part of the housing 2 by appropriate means such as bolting so as to face the holes 6I, 6□, . . . . Therefore, when the cam disc 6 rotates and moves in the axial direction of the plunger 4 according to its cam profile, the holes 61, 62 . ...
are successively opposed to the pickup coil 11.

The cam disk 6 is made of a suitable magnetic material, and a timing signal is output from the pickup coil 11 each time the holes 61, 6□, . . . approach and leave the pickup coil 11 in sequence. is the tip 1 of the pickup coil 11, as shown in the example in FIG.
This is at each timing when 1a reaches position A where it begins to face one of the holes.

According to such a configuration, the cam disk 6 can function as a pulsar with only slight processing, so the configuration is simple, and the phase between the pulsar and the cam profile configured in this way is simple. The deviation can be kept extremely small, and the phase will not shift due to the machining accuracy or wear of various parts installed between the drive shaft 5 and the cam disc 6, so the distribution type fuel injection pump 1 can be operated with extremely high precision. Actuation timing can be detected.

Furthermore, in the above embodiment, since the port processing is performed to provide a hole on the outer circumferential surface of the cam disc 6, the processing is easier than when a cog is provided, and it is easier to achieve accuracy, which is an effect unique to this embodiment. It is something. Additionally, carburization is generally required to increase the strength of each sliding part, and when installing cogs on the outer surface of a cam disk, measures must be taken to prevent carburization of the teeth. .

However, in the above embodiment, this is not necessary.

In some cases, it is of course possible to form cogs on the outer peripheral surface of the cam disk 6 in a pattern with predetermined angular intervals so that the cam disk 6 can function as a pulser. Examples are also within the scope of the invention.

(Effects) According to the present invention, as described above, since the cam disc is configured to have a function as a pulser for timing detection by providing unevenness on the outer circumferential surface, the gap between the drive shaft and the cam disc is The accuracy of detection timing is not affected by the dimensional accuracy or wear of each part, enabling highly accurate timing detection over a long period of time, and because the configuration is simple, it is also expected to reduce costs. It has excellent effects such as being able to

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a main part of an embodiment of a distribution type fuel injection pump equipped with a timing detection pulser according to the present invention;
FIG. 2 is a developed cross-sectional view showing the cam disk shown in FIG. 2 developed in the circumferential direction. 1...Distribution type fuel injection pump, 4...Plunger,
6... cam disc, 63.6□, 63. ···hole,
11...Pick amplifier coil.

Claims (1)

[Claims] 1. A timing detection pulser is characterized in that a cam disk has irregularities for detecting rotation on the outer circumferential surface of the cam disk in order to detect the operation timing of a distribution type fuel injection pump.