Valve operating system in internal combustion engine

A valve operating system in an internal combustion engine, that can be readily assembled and installed on the engine, including a casing coupled to an upper surface of a cylinder head, an armature, a pair of electromagnets for exerting electromagnetic forces on the armature in directions of opening and closing of an engine valve, and a pair of resilient means for biasing the engine valve in the opening and closing directions, respectively, and for retaining the armature at a predetermined neutral position by cooperation with each other during deenergization of both the electromagnets. The resilient means for closing the engine valve is mounted between a retainer fixed to the valve stem and a fixed position on the cylinder head, and the electromagnets are fixed within the casing which is constructed so that an upper portion of the stem can be inserted into the casing. Accommodated within the casing are the armature separatably coaxially connected at an upper end of the stem, and the resilient means for opening the engine valve and also exhibiting a resilient force for urging the armature against the first electromagnet to support the armature, when the armature is not connected to the stem.

The present invention relates to a valve operating system in an internal 
combustion engine, and particularly, to a valve operating system in an 
internal combustion engine including a casing coupled to an upper surface 
of a cylinder head, an armature operatively connected to a stem of an 
engine valve, a pair of electromagnets for applying an electromagnetic 
force to the armature in directions of opening and closing of the engine 
valve, and a pair of resilient means for biasing the engine valve in the 
opening and closing directions respectively and for retaining the armature 
at a predetermined neutral position by cooperation with each other during 
deenergization of both the electromagnets. 
BACKGROUND OF THE INVENTION 
Such a valve operating system is conventionally known, for example, from 
PCT International Patent Application Laid-open No. WO95/00959 and the 
like. In the valve operating system disclosed in that Patent Application, 
the armature is fixed to the upper end of the stem of the engine valve. In 
assembling the valve operating system to the cylinder head, the components 
disposed within the casing are assembled in sequence from the side of the 
cylinder head and finally, the casing is assembled to the cylinder head to 
cover these components. This assembling operation is carried out in a 
narrow space, and therefore the assemblability is poor. 
SUMMARY OF THE INVENTION 
The present invention has been accomplished with such circumstance in view, 
and it is an object of the present invention to provide a valve operating 
system in an internal combustion engine, wherein the assemblability of 
components is excellent. 
To achieve the above object, there is provided a valve operating system in 
an internal combustion engine, comprising a casing separatably coupled to 
an upper surface of a cylinder head, an armature movably accommodated 
within said casing and operatively connected to a stem of an engine valve, 
a first electromagnet disposed within the casing at a location in which it 
is opposed to said armature to exhibit an electromagnetic force for 
attracting the armature to open the engine valve, a second electromagnet 
disposed within the casing at a location in which it is opposed to the 
armature to exhibit an electromagnetic force for attracting the armature 
to close the engine valve, a first resilient means for exhibiting a 
resilient force for biasing the engine valve in an opening direction, and 
a second resilient means for exhibiting a resilient force for biasing the 
engine valve in a closing direction and for retaining the armature at a 
predetermined neutral position by cooperation with the first resilient 
means during deenergization of the first and second electromagnets, 
wherein the second resilient means is mounted between a retainer fixed to 
the stem and a fixed position on the cylinder head; the first and second 
electromagnets are fixed within the casing constructed so that the upper 
portion of the stem can be inserted from below into the casing; and the 
following two members are accommodated within the casing: (a) the armature 
to which the upper end of the stem is separatably coaxially connected, and 
(b) the first resilient means for exhibiting the resilient force for 
urging the armature against the first electromagnet to support the 
armature, when the armature is not connected to the stem. 
With such construction, the stem and the armature can be separated from 
each other, and both the electromagnets, the armature and the first 
resilient means can be accommodated and disposed within the casing to form 
a unit. In a condition in which the engine valve and the second resilient 
means have been assembled to the cylinder head, the unit is assembled to 
the cylinder head, thereby connecting the stem to the armature, thus 
completing the assembling of the valve operating system to the cylinder 
head. 
Further, according to the present invention, the first and second 
electromagnets are accommodated within the casing, so that their movements 
in directions away from each other are limited by opposite ends of the 
casing, and the valve operating system further includes a sleeve 
interposed between the two electromagnets to surround the armature. Thus, 
it is possible to appropriately set the distance between the 
electromagnets. 
Still further, according to the present invention, a guide shaft extending 
on the opposite side from the stem of the engine valve is fixed at its one 
end to the armature and slidably fitted in a guide member which is 
supported at an upper end of the casing. Thus, the movement of the 
armature, separatably connected to the stem, can be supported by the guide 
member, thereby avoiding, to the utmost, the exertion of vibration between 
the upper end of the stem and the armature during opening or closing of 
the engine valve to stabilize the behavior of the armature. 
Furthermore, according to the present invention, the guide member is 
supported at the upper end of the casing for movement in an axial 
direction of the stem; the casing is provided with a limiting means for 
adjustably limiting the extent of axially outward movement of the guide 
member, and the first resilient means is mounted between the guide shaft 
and the guide member. Thus, it is possible to freely adjust the axial 
position of the guide member to regulate the resilient forces of the first 
and second resilient means. 
Moreover, according to the present invention, a support tube is mounted at 
the lower end of the casing and is capable of being advanced and retreated 
in a direction coaxial with the stem, and a fixing means is also mounted 
at the lower end of the casing for fixing the support tube to the casing, 
so that the advanced or retreated position of the support tube can be 
regulated; and the first and second electromagnets with the sleeve 
interposed therebetween to surround the armature are clamped between the 
upper end of the casing and the upper end of the support tube. Thus, it is 
possible to firmly fix the electromagnets within the casing, while 
regulating the neutral position of the armature and the distance between 
the armature located at the neutral position and the electromagnets. 
Still further, according to the present invention, the casing has support 
portions integrally provided thereon at an outer peripheral of the casing 
at a plurality of points spaced circumferentially of the stem, the support 
portions being fastened to the upper surface of the cylinder head. Thus, 
in assembling, to the cylinder head, the unit including the casing as well 
as the electromagnets, the armature and the first resilient means 
accommodated within the casing, the axial center of the stem and the axial 
centers of the electromagnets and the armature can be reliably matched 
with one another.

DESCRIPTION OF A PREFERRED EMBODIMENT 
Referring first to FIG. 1, a pair of engine valves V, which are intake or 
exhaust valves, are disposed for each of the cylinders in a cylinder head 
5 of an internal combustion engine. The engine valve V is comprised of a 
valve member 7 capable of opening and closing a valve bore 6 provided in 
the cylinder head 5, and a stem 8 integrally connected to the valve member 
7 and slidably fitted into a guide tube 9. The guide tube 9 has, at its 
upper end, a flange portion 9a protruding radially outwards, and is fixed 
to the cylinder head 5 by press-fitting the flange portion 9a into the 
cylinder head 5 until it is engaged with an upper surface of the cylinder 
head 5. 
A valve operating system 10 according to the present invention is disposed 
on the cylinder head 5 and connected to upper end of the stem 8 of each of 
the engine valves V. Each of the valve operating systems 10 is the same 
and therefore only one will be described. 
The valve operating system 10 includes a casing 11 separatably coupled to 
the cylinder head 5, an armature 12 movably accommodated in the casing 11 
and operatively connected to the stem 8 of the engine valve V, a first 
electromagnet 13 disposed within the casing 11 at a location in which it 
is opposed to a lower surface of the armature 12 to exhibit a 
electromagnetic force for attracting the armature 12 to open the engine 
valve V, a second electromagnet 14 disposed within the casing 11 at a 
location in which it is opposed to the upper surface of the armature 12 to 
exhibit an electromagnetic force for attracting the armature 12 to close 
the engine valves V, a first coil spring 15 as a first resilient means for 
exhibiting a resilient force for biasing the engine valves V in an opening 
direction, and a second coil spring 16 as a second resilient means for 
exhibiting a resilient force for biasing the engine valves V in a closing 
direction and for retaining the armature 12 at a predetermined neutral 
portion by cooperation with the first coil spring 15 during deenergization 
of the first and second electromagnets 13 and 14. 
Referring also to FIG. 2, the casing 11 is fastened to the upper surface of 
the cylinder head 5 and is common to the pair of engine valves V. The 
casing 11 is comprised of a casing body 17 and lid plate 18 fixed to an 
upper surface of the casing body 17. The casing body 17 is provided with 
an accommodating bore 19 which extends coaxially with each stem 8 in 
individual correspondence to each of the engine valves V. The lid plate 18 
is fastened to the upper surface of the casing body 17 by a plurality of, 
e.g., four bolts 20, so that it closes the upper ends of both the 
accommodating bores 19. 
Three vertically extending support portions 21.sub.1, 21.sub.2 and 21.sub.3 
are integrally provided at a lower portion of an outer periphery of the 
casing body 17. The support portions 21.sub.1 and 21.sub.2 are disposed at 
two circumferentially spaced points relative to the stem 8 of one of the 
engine valves V, and the support portions 21.sub.2 and 21.sub.3 are 
disposed at two circumferentially spaced points relative to the stem 8 of 
the other engine valve V. Fastening bolts 22 are inserted through the 
support portions 21.sub.1 to 21.sub.3, and the casing 11 is fastened to 
the upper surface of the cylinder head 5 by threaded insertion of the 
fastening bolts 22 into the cylinder head 5. 
Referring also to FIG. 3, a support collar 24 is integrally provided at a 
lower end of the casing 11, i.e., at a lower end of the casing body 17 and 
protrudes radially inwards from an inner surface of the accommodating bore 
19. Threadedly mounted on the support collar 24 is a support tube 25 
capable of being advanced and retreated coaxially with the stem 8 of the 
engine valve V, and a fixing means 26 is threadedly mounted on the support 
tube 25 for fixing the support tube 25 to the support collar 24, so that 
the advanced or retreated position of the support tube 25 can be adjusted. 
The support tube 25 is threadedly engaged with internal threads 27 provided 
on an inner periphery of the support collar 24 and can be advanced and 
retreated in a direction coaxial with the stem 8 by turning thereof. The 
fixing means 26 is formed into a double-nut structure by a structure of 
threaded engagement with the internal threads 27 of the support tube 25 
and by a retaining nut 28 which is threadedly fitted over the support tube 
25 and engaged with a lower surface of the support collar 24. Thus, the 
fixing means 26 is capable of firmly fixing the support tube 25 to the 
lower end of the support collar 24, i.e., the casing 11, so that the 
support tube 25 can be advanced and retreated in the direction coaxial 
with the stem 8. 
On the other hand, a cylindrical portion 30 is integrally provided at the 
upper end of the casing 11, i.e., on the lid plate 18 to protrude upwards 
and defines a support bore 29 coaxial with the stem 8. An upper portion of 
a cylindrical guide member 31 is slidably received in the support bore 29 
for movement along an axis of the stem 8. A slide bore 32 is provided in 
the guide member 31 over the entire vertical length of the guide member 
31. 
A limiting means 33 is mounted on the cylindrical portion 30, so that the 
extent of the axial outward movement of the guide member 31 can be 
adjusted. The limiting means 33 is formed into a double-nut structure by 
(1) a cap nut 34 which is threadedly fitted over the cylindrical portion 
30, so that the upper end of the guide member 31 abuts against the closed 
end of the cap nut 34, and (2) a retaining nut 35 which is threadedly 
fitted over the cylindrical portion 30 to limit the advanced or retreated 
position of the cap nut 34. Thus, the extent or position of the axially 
outward movement of the guide member 31 can be regulatably firmly limited. 
An open bore 36 is provided in the closed end of the cap nut 34 and 
coaxially communicates with the slide bore 32 in the guide member 31. 
The upper portion of the stem 8 of the engine valve V is inserted from 
below into the casing body 17, so that it is coaxially passed through the 
support tube 25. A retainer 38 is fixed to the upper end of the stem 8 by 
a split cotter 37. A cap-like receiving member 39 abuts against the upper 
end of the cylinder head 5 to cover the flange portion 9a of the guide 
tube 9. The second coil spring 16 is mounted between the retainer 38 and 
the receiving member 39 to surround the stem 8 which is axially and 
slidably passed through the receiving member 39, so that the stem 8, i.e., 
the engine valve V is resiliently biased in the closing direction by the 
spring force of the second coil spring 16. Moreover, a ring-like seal 
member 40 slidable on the outer surface of the stem 8 is retained within 
the receiving member 39. 
The armature 12 is formed into a disk-like shape and has a cylindrical 
portion 12a, a collar portion 12b protruding radially outward from an 
axial middle of the cylindrical portion 12a, and a limiting collar 12c 
protruding radially inward from the axial middle of the cylindrical 
portion 12a. 
A guide shaft 41 extending coaxially with the stem 8 of the engine valve V 
on the opposite side from the stem 8 is fixed at one end thereof to the 
armature 12. More specifically, an engage collar portion 41a is provided 
at one end, i.e., a lower end of the guide shaft 41 to engage a lower 
surface of the limiting collar portion 12c of the armature 12, and a ring 
42 fitted over and fixed to a lower portion of the guide shaft 41 by 
press-fitting or the like is engaged with an upper surface of the limiting 
collar portion 12c. Thus, the limiting collar portion 12c of the armature 
12 is clamped by the engage collar portion 41a and the ring 42, whereby 
one end of the guide shaft 41 is fixed to the armature 12. 
The upper portion of the guide shaft 41 is slidably fitted into the slide 
bore 32 in the guide member 31. The first coil spring 15 surrounding the 
guide member 31 and the guide shaft 41 is mounted between a stepped 
portion 31a provided at the upper portion of the guide member 31 to face 
the armature 12, a stepped portion 41b provided at the lower portion of 
the guide shaft 41 to face the opposite side from the armature, and the 
ring 42, so that the armature 12 is resiliently biased downwards, i.e., in 
the opening direction of the engine valve V by the spring force of the 
first coil spring 15. 
The upper end of the stem 8 of the engine valve V is separatably coaxially 
connected to the armature 12, and a recess 43 for insertion and contacting 
of the upper end of the stem 8 is provided in a lower end face of the 
guide shaft 41 that is coaxially fixed to the armature 12. 
The first electromagnet 13 is fixedly disposed at a lower portion of the 
accommodating bore 19, so that it is opposed to the lower surface of the 
armature 12. The first electromagnet 13 is comprised of a cylindrical 
inner yoke 44 coaxially surrounding the stem 8 and the second coil spring 
16, a cylindrical outer yoke 45 fitted in the accommodating bore 19 to 
coaxially surround the inner yoke 44, and a ring-like coil assembly 46 
interposed between the inner and outer yokes 44 and 45 and having a coil 
wound around a bobbin made of a synthetic resin. A radially outward 
protruding flange portion 44a is integrally provided at a lower end of the 
inner yoke 44 and has an outer edge engaged with a lower end of the outer 
yoke 45. 
The second electromagnet 14 is fixedly disposed at an upper portion of the 
accommodating bore 19, so that it is opposed to the upper surface of the 
armature 12. The second electromagnet 14 is comprised of a cylindrical 
inner yoke 47 coaxially surrounding the guide shaft 41 and the guide 
member 31, a cylindrical outer yoke 48 fitted in the accommodating bore 19 
to coaxially surround the inner yoke 47, and a ring-like coil assembly 49 
interposed between the inner and outer yokes 47 and 48 and having a coil 
wound around a bobbin made of a synthetic resin. A radially outward 
protruding flange portion 47a is integrally provided at an upper end of 
the inner yoke 47 and has an outer edge engaged with an upper end of the 
outer yoke 48. 
A sleeve 50 is fitted into the accommodating bore 19 in a ring-like 
configuration to surround the armature 12 and is interposed between the 
outer yoke 45 of the first electromagnet 13 and the outer yoke 48 of the 
second electromagnet 14. The lower end of the inner yoke 44 of the first 
electromagnet 13 is supported in an abutting manner on the upper end of 
the support tube 25. A shim 51 is interposed between the upper end of the 
inner yoke 47 of the second electromagnet 14 and the lid plate 18 of the 
casing 11. More specifically, the first and second electromagnets 13 and 
14 with the sleeve 50 interposed therebetween are fixed within the casing 
by clamping between the shim 51 disposed at the upper end of the casing 11 
and the upper end of the support tube 25. 
A grommet 52 is fitted in the lower end portion of the casing body 17 which 
corresponds to the support collar 24. A pair of lead wires 53 connected to 
the coil of the coil assembly 46 of the first electromagnet 13 are passed 
through the grommet 52 and drawn outside the casing 11. A grommet 54 is 
fitted in the lid plate 18, and a pair of lead wires 55 connected to the 
coil of the coil assembly 49 of the second electromagnet 14 are passed 
through the grommet 54 and drawn outside the casing 11. 
The operation of the embodiment will be described below. The upper portion 
of the stem 8 of the engine valve V is capable of being inserted from 
below into the casing 11 coaxially through the support tube 25 at the 
lower end of the casing 11. The first and second electromagnets 13 and 14 
are fixed within the casing 11, and the armature 12, to which the upper 
end of the stem 8 is separatably coaxially connected, is accommodated in 
the casing 11. The first coil spring 15 for biasing the engine valve V in 
the opening direction is mounted between the guide shaft 41 fixed to the 
armature 12 and the guide member 31 supported at the upper end of the 
casing 11, and is accommodated in the casing 11. On the other hand, the 
retainer 38 is fixed to the upper end of the stem 8, and the second coil 
spring 16 is mounted between the receiving member 39 located at a fixed 
position on the upper surface of the cylinder head 5 and the retainer 38. 
Therefore, as shown in FIGS. 3 and 4, the first and second electromagnets 
13 and 14, the armature 12, the guide shaft 41 fixed to the armature 12 
and the like can be accommodated and disposed within the casing 11 to form 
a pre-assembled unit U. Thus, the pre-assembled unit U can be prepared by 
a previous assembling conducted away from the narrow space above the 
cylinder head 5. In this pre-assembled unit U, the armature 12 is urged 
against the first electromagnet 13 by the first coil spring 15 and 
supported by the first electromagnet 13. 
In assembling the valve operating system 10 to the cylinder head 5, the 
pre-assembled unit U need only be assembled to the cylinder head 5 in a 
condition in which the engine valves V, the second coil spring 16 and the 
like have been assembled to the cylinder head 5, as shown in FIG. 4. The 
upper end of the stem 8 inserted from below into the casing 11 is inserted 
into the recess 43 in the lower end face of the guide shaft 41 to abut 
against the bottom of the recess 43, and the armature 12 is coaxially 
connected to the stem 8 and pushed upwards away from the first 
electromagnet 13 by installing the three bolts 22. This completes the 
assembling of the valve operating system 10 and completes the attachment 
of the valve-operating system 10 to the cylinder head 5. Thus, it is 
possible to enhance the assemblability of the valve operating system 10. 
Moreover, the support tube 25, which is capable of being advanced and 
retreated in the direction coaxial relative to the stem 8, is mounted at 
the lower end of the casing 11 and the fixing means 26 is also mounted at 
the lower end of the casing 11 for fixing the support tube 25 to the 
casing 11, so that the advanced or retreated position of the support tube 
25 can be adjusted before installing the unit U on the cylinder head 5. 
The first and second electromagnets 13 and 14 with the sleeve 50 
interposed therebetween are clamped between the shim 51 at the upper end 
of the casing 11 and the upper end of the support tube 25. Therefore, the 
electromagnets 13 and 14 in the pre-assembled unit U can be firmly fixed 
within the casing 11, while regulating the neutral position of the 
armature 12 determined by the first and second coil springs 15 and 16 as 
well as the distance between the armature 12 located at the neutral 
position and the electromagnets 13 and 14. 
The guide member 31 is supported at the upper end of the casing 11 for 
movement in the axial direction of the stem 8, and the limiting means 33 
for regulatably limiting the position of axially outward movement of the 
guide member 31 is mounted on the casing 11. The first coil spring 15 is 
mounted between the guide shaft 41 fixed to the armature 12 and the guide 
member 31. Therefore, the axial position of the guide member 31 can be 
freely adjusted to regulate the spring force of the first coil spring 15 
and further to adjust the spring force of the second coil spring 16 in 
accordance with a variation in spring force of the first coil spring 15. 
Further, the support portions 21.sub.1 to 21.sub.3 are integrally provided 
on the outer periphery of the casing 11 at the plurality of points spaced 
circumferentially of each stem 8 and are fastened to the upper surface of 
the cylinder head 5 by the fastening bolts 22. Therefore, the axial 
centers of the first and second electromagnets 13 and 14 and the armature 
12 accommodated in the pre-assembled unit U can be reliably matched with 
the axial center of the stem 8 of the engine valve V. 
The guide shaft 41 fixed to the armature 12 and the upper end of the stem 8 
of the engine valve V are merely in contact with each other, and the guide 
shaft 41 is slidably fitted in the guide member 31 supported at the upper 
end of the casing 11. Therefore, the movement of the armature 12, 
separatable from the stem 8, can be supported by the guide member 31 to 
avoid, to the utmost, the exertion of vibration between the upper end of 
the stem 8 and the armature 12 during opening or closing of the engine 
valve V, thereby stabilizing the behavior of the armature 12. 
The electromagnets 13 and 14 are firmly fixed within the casing 11, as 
described above and hence, cannot be finely vibrated with opening or 
closing of the engine valve V, thereby enabling the opening and closing of 
the engine valve V to be stabilized. 
Although the embodiment of the present invention has been described in 
detail, it will be understood that the present invention is not limited to 
the above-described embodiment, and various modifications in design may be 
made without departing from the spirit and scope of the invention defined 
in claims. 
As discussed above, according to the present invention, the valve stem and 
the armature can be separated from each other, and both the 
electromagnets, the armature and the first resilient means can be 
accommodated and disposed within the casing to form the unit. In the 
condition in which the engine valve and the second resilient means have 
been assembled to the cylinder head, the unit can be assembled to the 
cylinder head, thereby connecting the stem to the armature, thus 
simultaneously completing the assembling of the valve operating system and 
the attachment of the valve operating system to the cylinder head. 
Further, according to the present invention, the distance between the first 
and second electromagnets can be appropriately set by the fact that the 
sleeve is interposed between both the first and second electromagnets. 
Still further according to the present invention, the movement of the 
armature separatably connected to the stem can be supported by the guide 
member to avoid, to the utmost, the exertion of vibration between the 
upper end of the stem and the armature during opening or closing of the 
engine valve to stabilize the behavior of the armature. 
Moreover, according to the present invention, it is possible to regulate 
and limit the extent of axially outward movement of the guide member 
supported at the upper end of the casing by the limiting means, thereby 
freely regulating the axial position of the guide member to adjust the 
resilient forces of the first and second resilient means. 
Furthermore, according to the present invention, it is possible to firmly 
fix the first and second electromagnets with the sleeve interposed 
therebetween within the casing in such a manner that the first and second 
electromagnets are clamped between the upper end of the casing and the 
upper end of the support tube, while regulating the neutral position of 
the armature and the distance between the armature in the neutral position 
and the electromagnets. 
Further, according to the present invention, in assembling, to the cylinder 
head, the unit including the casing as well as the electromagnets, the 
armature and the first resilient means accommodated within the casing, the 
axial center of the valve stem can be reliably matched with the axial 
centers of the electromagnets and the armature.