Electric governor

An electric governor of the type, in which the fuel injection regulating member of a fuel injection pump is driven by means of a solenoid type electromagnetic actuator. The governor includes a link mechanism being rotatably attached to the casing of the governor. In the link mechanism, the electromagnetic actuator is connected to its first point, the fuel injection regulating member is connected to its second point, and the force of a spring for acting against the attraction of the electromagnetic actuator is exerted upon its third point.

FIELD OF THE INVENTION 
The present invention relates to an electric governor of fuel injection 
pump for an internal combustion engine, especially, a Diesel engine. 
DESCRIPTION OF THE Prior Art 
Most of the conventional governors using a solenoid type electromagnetic 
actuator are constructed such that there is disposed in the 
electromagnetic actuator a spring for generating a force which acts 
against the attraction of the electromagnetic actuator. In some of the 
governors, on the other hand, there is disposed outside of the 
electromagnetic actuator a spring for generating the force which acts 
against the attraction of the electromagnetic actuator. Those springs are 
restricted to one which is arranged in the same direction as the moving 
direction of a fuel injection regulating member thereby to counteract the 
attraction of the electromagnetic actuator through the fuel injection 
regulating member. 
Moreover, the construction, in which the spring is disposed in the 
electromagnetic actuator, has the following defects. First of all, since 
there is a limit in the spring mounting size of the electromagnetic 
actuator, there is little degree of freedom in the design of the spring. 
Next, since it is intended to retain a space for mounting the spring, the 
attracting area of a magnetic member is reduced to reduce the attraction, 
and the spring may occasionally exert an undesired influence upon the 
magnetic field thereby to reduce the attraction. Moreover, it is 
remarkably difficult to effect the adjustment of the mounting load upon 
and the replacement of the spring. 
On the other hand, the latter construction, in which the spring is disposed 
outside of the electromagnetic actuator so that its force may act against 
the attraction at the output rod of the electromagnetic actuator through 
the fuel injection regulating member, has the following defects. In this 
construction, first of all, since the spring mounting position and size 
are restricted, there is little degree of freedom in the design of the 
spring. In the construction, moreover, it is also remarkably difficult to 
effect the adjustment of the mounting load upon and the replacement of the 
spring. 
SUMMARY OF THE INVENTION 
It is, therefore, an object of the present invention to increase the 
attraction of an electromagnetic actuator, to increase the degree of 
freedom in the design of a spring for generating a force which acts 
against the attraction of the electromagnetic actuator, and to make it 
possible to facilitate the adjustment of the spring force and the 
replacement of the spring.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
In FIGS. 1 to 3, reference numeral 1 indicates a governor casing which is 
fixed to a not-shown fuel injection pump by means of bolts. Numeral 2 also 
indicates a governor casing which in turn is fixed to the former governor 
casing 1 by means of not-shown bolts. Numeral 3 indicates a solenoid type 
electromagnetic actuator, in which a coil 6 of a wire wound on the outer 
circumference of a bobbin 5 is fixed in a cylindrical casing 4 made of a 
magnetic material. In the inner wall of the coil 6, there is fixed a 
stationary core 7 made of a magnetic material, which has its one end 
formed with a frusto-conical protrusion and has bearings 12 and 13 
press-fitted in the center portions of both its ends. In these bearings 12 
and 13, moreover, there is borne an output rod 9 such that it can move to 
the right and left, as viewed in FIG. 1 and can rotate. To one end of this 
output rod 9, there is fixed a moving core 8 which is made of a magnetic 
material and which is formed with such a frusto-conical recess as faces 
the frusto-conical protrusion of the stationary core 7. To the other end 
of that output rod 9, there is fastened by means of a screw a connecting 
member 10 which is formed with an annular groove. Numeral 11 indicates a 
cover which is made of a non-magnetic material and which is fixed to the 
casing 4 by means of non-shown bolts. 
Numeral 14 indicates a link mechanism which has its fulcrum fixed at the 
governor casing 1 and which has such a construction as is shown in detail 
in FIG. 3. Numeral 22 indicates a block which is fixed to the governor 
casing 1 by means of later-described bolts thereby to provide the fulcrum 
of the link mechanism 14. In the block 22, there is press-fitted a 
cylindrical bush 23 which provides that fulcrum. The block 22 is formed 
with holes 24 and 25 for receiving the bolts to be fastened to the 
governor casing 1. Numeral 19 indicates a cylindrical shaft which is 
rotatably fitted in the bush 23. Both those ends of the cylindrical shaft 
19, which protrude from that block 22, are formed with holes 20 and 21 
which are directed to intersect the axis of the shaft 19 at a right angle. 
Numeral 16 indicates a lever which is made of a metal plate and which has 
its one end fixed to the other end of a pin 15 having its one end formed 
into a round portion. To the other end of the lever 16, there is fixed a 
bush 17 which is formed with both an axial hole for receiving the shaft 19 
and a hole 8 intersecting the axial hole at a right angle. Numeral 26 
indicates a lever which is made of a metal plate and which has its one end 
formed with a slit 27 and its other end fixed to one end of a bush 28. 
Numeral 30 indicates a lever which is made of a metal plate and which has 
a pin 31 fixed to its one end. Moreover, a roller 32 is rotatably held on 
the pin 31 by means of a cir-clip 33 (as shown in FIG. 2). The 
aforementioned lever 30 has its other end fixed to the lever 26 at an 
angle. 
The bush 28 is formed like the bush 17 with both an axial hole for 
receiving the shaft 19 and a hole 29 intersecting the axial hole at a 
right angle. The bush 17 is fitted on that portion of the shaft 19, which 
protrudes upward from the block 22, and is fixed to the shaft 19 by means 
of a not-shown spring pin such that its hole 18 is aligned with the hole 
20 of the shaft 19. The bush 28 is also fitted on that portion of the 
shaft 19, which protrudes downward from the block 22, and is fixed to the 
shaft 19 by means of a not-shown spring pin such that its hole 29 is 
aligned with the hole 21 of the shaft 19. Numerals 36 and 37 indicate 
clearance adjusting shims which are sandwiched, respectively, between the 
bush 17 and the block 22 and between the bush 28 and the block 22. 
In FIG. 2, numerals 34 and 35 indicate bolts which fasten the block 22 to 
the governor casing 1. Numeral 38 indicates a pin which has its one end 
formed into a round portion and its other end fixed to a fuel injection 
regulating member 50. The round portion of the pin 38 is fitted in the 
slit 27 of the lever 26 so that the motions of the lever 26 are 
transmitted through the pin 38 to the fuel injection regulating member 50. 
Numeral 39 indicates a cylindrical rod which has its one end formed with a 
stepped portion 40 and which has a core 43 of a position sensor fixed to 
its other end. The roller 32 abuts against one side of the stepped portion 
40 whereas a spring 41 abuts against the other side. Numeral 45 indicates 
a casing which is fixed to the governor casing 1 by means of bolts. To one 
end of that casing 45, there is fixed a hollow bush 42, in which the rod 
39 is slidably and rotatably held. The spring 41 is sandwiched under 
compression between the stepped portion 40 of the rod 39 and the bush 42. 
Numeral 51 indicates a shim for adjusting the mounting load of the 
compression spring 41. In the casing 45, there is fixed an inductance 
changing type non-contact position detector 44 having a hole, in which 
there is arranged the core 43 such that it can linearly move. Numeral 52 
indicates a shim for adjusting the relative positions of the core 43 and 
the position detector 44. Numeral 48 indicates the cam shaft of a 
not-shown fuel injection pump. Numeral 47 indicates a disc which is made 
of a magnetic material, which is fixed to one end of the cam shaft 48 by 
means of a round nut 49 (as shown in FIG. 1) and which has its outer 
circumference formed with equi-distantly spaced grooves. Numeral 46 
indicates an electromagnetic pickup which has its leading end fixed to the 
governor casing 1 while being spaced at a predetermined distance from the 
outer circumference of the disc 47. Although not shown, moreover, the fuel 
injection regulating member 50 is equipped for the purpose of preventing 
the chattering with a compression spring which has a weaker spring force 
than that of the spring 41 and which is sandwiched between the housing of 
the not-shown fuel injection pump and the pin 38 thereby to always thrust 
the fuel injection regulating member in a direction to reduce the fuel 
injection rate (i.e., rightwardly of FIG. 1). 
With construction thus far described, when the coil 6 of the 
electromagnetic actuator 3 is energized, the moving core 8 is attracted by 
the resultant magnetic force toward the stationary core 7 so that it moves 
leftwardly of FIG. 1. The movement of that moving core 8 is transmitted to 
the output rod 9 which is fixed to the moving core 8. This movement of the 
output rod 9 is transmitted through the connecting member 10 and the pin 
15 to the lever 16 and further through the shaft 19 to the lever 30 which 
is made rotatable integrally with the lever 16. This motion of the lever 
30 is converted through the pin 31 and the roller 32 into the linear 
movement of the rod 39 thereby to compress the compression spring 41 which 
is in abutment contact with the stepped portion 40 of the rod 39. On the 
contrary, this force of the spring 41 is transmitted through the stepped 
portion 40, the roller 32, the pin 31, the lever 30, the shaft 19, the 
lever 16, the pin 15, the connecting member 10 and the output rod 9 to the 
moving core 8, so that the moving core 8 and the output rod 9 reside at 
positions where the attraction and the spring force are balanced. On the 
other hand, the fuel injection regulating member 50 is connected through 
the pin 38 to the lever 26, which in turn can swing together with the 
lever 16 through the shaft 19 similarly to the lever 30, so that the 
regulating member 50 is shifted in accordance with the position of the 
output rod 9. As a result, the position of the fuel injection regulating 
member 50 can be controlled in accordance with the level of the current to 
flow through the coil 6 of the electromagnetic actuator 3 thereby to 
regulate the fuel injection rate of the fuel injection pump. 
In the embodiment, as shown, the movement of the output rod 9 in the 
leftward direction, as viewed in FIG. 1, in case the electromagnetic 
actuator 3 is energized, is transmitted as the leftward motion of the fuel 
injection regulating member 50, i.e., as the motion in a direction to 
increase the fuel injection rate. In case the electromagnetic actuator 3 
is deenergized, on the contrary, the fuel injection regulating member 50 
shifts in the rightward direction of FIG. 1. i.e., in a direction to 
reduce the fuel injection rate to zero. As a result, in case the current 
to the electromagnetic actuator is interrupted by an accident, the fuel 
injection rate can be reduced to zero thereby to prevent the engine from 
excessively rotating. On the other hand, the core 43 fixed to the rod 39 
conducts the linear movements integrally with the rod 39 so that the 
output of the inductance changing type position sensor 44 becomes such an 
output as varies in accordance with the position of the fuel injection 
regulating member 50 which is made coactive with the rod 39. By feeding 
that output to a not-shown electric control circuit, it is enabled to 
effect the position control. Moreover, since a signal having a frequency 
proportional to the r.p.m. of the engine can be generated by the coactions 
between the disc 47 and the electromagnetic pickup 46, the engine r.p.m. 
cam be controlled in a fed-back manner by feeding that signal to the 
not-shown control circuit. The casing 45 is fixed to the governor casing 1 
by means of bolts so that it can be mounted and demounted from the outside 
of the governor casing. As a result, it is possible to replace the spring 
41 and the shim 51, and it is easy to change the spring constant for 
coping with the attraction of the electromagnetic actuator 3 and to adjust 
the mounting load. 
Although, in the embodiment thus far described, the link mechanism 14 is 
constructed of an integrally movable one, it may be composed of a 
plurality of such links as can move respectively but together such that 
the respective links are swung in arbitrary planes. 
Moreover, since the bush 42 is fixedly press-fitted in the casing 45, it 
may be fixedly fastened to the casing 45 by means of screws and nuts, for 
example, so that it can be moved to adjust the mounting load of the spring 
41. 
Still moreover, the position sensor 44 to be used may be of a resistance 
changing contact type. 
As has been described hereinbefore, according to the present invention, by 
disposing outside of the electromagnetic actuator the spring for 
generating the force which acts against the attraction of the 
electromagnetic actuator, this attraction can be increased while 
facilitating the design of the spring. By making such a mechanism as 
causes the force of the spring to counteract the attraction of the 
electromagnetic actuator through the link mechanism, the restriction to 
the mounting position of the spring is reduced so that the spring can be 
arranged at a position, where its interference with the parts of the 
engine body is obviated, and the spring having its force adjusted can be 
easily replaced from the outside of the governor.