CA1184453A - Valve-rotating device - Google Patents
Valve-rotating deviceInfo
- Publication number
- CA1184453A CA1184453A CA000383478A CA383478A CA1184453A CA 1184453 A CA1184453 A CA 1184453A CA 000383478 A CA000383478 A CA 000383478A CA 383478 A CA383478 A CA 383478A CA 1184453 A CA1184453 A CA 1184453A
- Authority
- CA
- Canada
- Prior art keywords
- valve
- plate
- rotating device
- spring
- rotating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/32—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for rotating lift valves, e.g. to diminish wear
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Valve-Gear Or Valve Arrangements (AREA)
- Valve Device For Special Equipments (AREA)
Abstract
ABSTRACT
A valve-rotating device for an internal combustion engine is described.
The device has two rotating parts one of which is connected to the upper spring-plate of the valve and the other connected through the lower spring-plate and a unidirectional clutch to the cylinder head. The unidirectional clutch locks the other spring-plate against rotation as the valve spring and upper spring-plate move down. Interengaging members on the two rotating parts, therefore cause rotation of the one rotating part. This rotation is transmitted via the upper spring-plate and valve-stem to the valve head. Various interengaging members are disclosed. For example pins in one of the rotating parts engages sloping grooves in the other. Alternatively, balls running in sockets and cooperating with oblique grooves may be used. Wear is slight and the device can be operated at high speed.
A valve-rotating device for an internal combustion engine is described.
The device has two rotating parts one of which is connected to the upper spring-plate of the valve and the other connected through the lower spring-plate and a unidirectional clutch to the cylinder head. The unidirectional clutch locks the other spring-plate against rotation as the valve spring and upper spring-plate move down. Interengaging members on the two rotating parts, therefore cause rotation of the one rotating part. This rotation is transmitted via the upper spring-plate and valve-stem to the valve head. Various interengaging members are disclosed. For example pins in one of the rotating parts engages sloping grooves in the other. Alternatively, balls running in sockets and cooperating with oblique grooves may be used. Wear is slight and the device can be operated at high speed.
Description
The invention relates ko a valve-rotating device, more particular]y for internal-combustion engines, the said device comprlsing a valve-spring adap-ted to be held between an upper and a lower spring-plate or retainer and a uni-directional clutch, associated with the said lower spring-plate or the cylinder-head, which, as the valve is loaded and unloaded, permits the valve to rotate in one direction only.
A valve-rotating device of this kind is known in principle (German OS 28 ~1 ~89) which was published on 23.09.1978 in the name of Blohm v. Voss, AG.
The known valve-rotating device makes use of the twisting of a helical spring as it is loaded and unloaded, in conjunction with a free-wheeling means, e.g. a one-way clutch, to produce stepwise rotation of the valve. In this case, a free-wheeling means is associated with each of the two concentrically arranged helical springs, the turns of which are wound in opposite directions. The two free-wheeling means both lock in the same direction. Thus each time the valve opens and closes, each of the two springs is acted upon in such a manner that, with opposing movement of the valve stepwise rotation thereof occurs. The dis-advantage of this arrangement is that the rotational velocity of the valve is de-pendent mainly upon engine r.p.m. Thus at low camshaft r.p.m., the valve rotates only in very small steps or not at all. Furthermore, the rotary motion is de-pendent upon a very wide variety of factors, such as fric-tional torque in the valve guide, mass inertia moment, and the like, which have different effects at different rotational velocities.
In addition to the foregoing are various proposals ~German AS 19 55 820 published on 2~.09.1963 in the name of Tewes-Thompson GmbH German AS 21 10 708 published on 05.03.1971 in the name of Tewes-Thomspon GmbH German OS 21 16 086 published on 02.0~.1971 in the name of Tewes-Thompson GmbH German OS 26 40 383 publlshed on 09.09.1976 in the name of Tewes-Thompson GmbH German OS 27 57 ~55 published on 22.12.1977 in the name of TRW. Inc.) using rolling or sliding -r- E 1398 5~
elements, in pockets having sloping planes arranged concentrically around the axis of a base-element, which are loaded by tangentially acting springs adapted to be compressed, when the rolling or sliding elements are loaded, in the direc-tion of the flat sides of the pockets. They co-opera-te with a spring-element which tensions itself in the axial direction of the valve, the rolling or sliding elements being unloaded in the axial direction of the valve as the tension of the said spring-element increases, and being unloaded as the tension of the spring-element decreases, to produce relative rotation between the base-element and thespring-element. ~y using sloping planes having dif:Eerent configurations and different slopes, and equipped with differen~ rolling and sliding elements, at-tempts have been made to cause the rolling elements to travel as uniformly as possible in the peripheral direction, and thus to impart a uniform rotary motionto the valve. All of these valve-rotating devices are characteri~ed by a plur-ality oE individual parts, springs possessing different properties, and limited ability to rotate the valve. In view of the complexity of the design, suffi-ciently reliable operation is not assured.
In view of the foregoing disadvantages, attempts have also been made to achieve uniform rotation of the valve by means of positive controls associated with the engine-block. The disadvantage of this is that these positive controls act upon the respective upper spring-plates. This results in an expensive designwhich is difficult to fit to existing engines because of the large amount of space required, and which cannot be used with high-speed engines ~German OS 20 54 351 published on 05.11.1970 in the name of H. D. Klockner, et al; 21 28 110 published on 05.06.1971 in the name of H. D. Klockner, et al; 20 54 349 published on 05.11.1970 in the name of H. D. Klockner, et al; 20 54 362 published on ~49~5~
05.11.1970 in the name of ~I. D. Klockner, et al; and 27 39 403 published on 01.09.1977 in the name of ~I. D. Klockner, et al).
It is the purpose of the invention to provide a valve-rotating device which may be applied to both high and low-speed engines, which at all times en-sures adequate valve-rotation without rotating the springs, and which is as free as possible from wear.
According to the invention, this purpose is achieved in that a two-part rotating element is arranged between the upper and lower spring-plates, the two parts engaging with each other and rotating with the valve, the lower part being connected to the cylinder-head through the unidirectional clutch, and the upper part being connected to the upper spring-plate.
In this connection, it is desirable for the cylindrical rotating part to be associated with the unidirectional clutch positively connected to the valve-spring, the rotating part comprising guide-slots for the pin constituting the upper part.
In the valve-rotating device of this kind, the mechanism which rotates the valve is colmected to the unidirectional clutch and therefore rotates with the valve. The system is moreover designed in such a manner that rotation of the valve is always achieved, even at low engine r.p.m., dependently upon the mass inertia moments of the unidirectional clutch and the rotating part, and upon fric-tional torque in the valve-guide. By dispensing with purely -positive control, which inevitably takes up substantially more space, and by associating the part which rotates the valve with the unidirectionalclutch arranged upon the lower spring-plate, optimal use is made of the available space and any change or weight increase in the vicinity of the upper spring-plate is almost completely avoided.
This makes it possible to use a valve-rotating device of this kind in high-speed engines also, and to achieve high rotational velocities of the valve.
_3 5i3 Wear between the pin and the guide slot, which rub against each other~
is preferably limited in that the guide-slots are in the form of wedge-shaped recesses, the edges thereof which come into contact with the pin being hardened.
According to one design, the edges and the tip of the pin are coated with hard metal. This prevents damage even under the heaviest loads; wear is further minimized by the presence in this area of engine-oil.
The magnitude of the rotary motion of the valve during each cycle is predetermined by the slope of the guide-slot or recess. It has been found that optimal rotary motion of the valve is assured, even at different velocities, if the two parts of the rotating device turn in relation to each other by between 6 and 12 at each valve-stroke.
In the case of high-speed engines in particular, it may be desirable B to provide the ~-p of the pin with a ball-bearing adapted to rotate about an axis at right angles to the valve-stem. A design of this kind also largely eliminates frictional losses. Here again, the oil in this area also assists in lubricating the ball-bearing.
An advantageous example of embodiment of the invention, from the point of view of weight, provides for the rotating device to be arranged within the valve-spring and to have, at its upper edge, a sloping slot which guides the pin or cam. Here again, valve-spring torsion is used to produce subsequent rotary motion of the valve itself.
According to the invention, valve-spring torsion may be dispensed with if, with a rotating part comprising a closed gap, the valve-spring is mounted to rotate freely, in the vicinity of the lower spring-plate, by means of an axial bearing. In this design, only the gap in the rotating part, and thus the rotat-ing part itself, produces rotation of the valve and valve-plate.
In order to be able to use the vertical motion of the valve, both in s~
opening and closing, to rotate the valve-plate, provision is made, according to the invention, for a rotating part with a gap also to be arranged outside the valve-spring, and for a separate unidirectional clutch, acting in the same direc tion, to be associated therewith. If two such rotating mechanisms, with separate unidirectional clutch, are used for a single valve, -the masses to be moved are again kep-t small, in that one of the rotating parts is arranged outside and the other inside the valve-spring. In this collnection it is desirable for the slop-ing slot in the inner,and the gap inthe outer, rotating part to run in opposite directions, and to have a different inclination. As a result of this, the valve is rotated both when it opens and when it closes, and the rotational veloci-ty upon opening may differ from that upon closing, depending upon the slope of each gap. The two unidirectional clutch act in the same direction, i.e. they lock and rotate in the same direction of rotation.
Further substantial reduction in wear is achieved in that the upper and lower parts of the valve-rotating device are arranged close together as they move in relation to each other, and are connected together by balls which rotate, the said balls being guided in the upper part in a ball-socket and, in the lower part, in a ball-groove running obliquely downwards. A device of this kind rotates at a higher r.p.m., and more reliably, than e~isting rotating devices. The balls in no way affect this rotation and thus cause little wear. Furthermore, since any wear arising occurs in the balls themselves, these can be replaced whersupon the valve-rotating device becomes fully serviceable again without replacing or rework;ng any other parts. If any wear occurs, replacement is a simple matter and takes little time.
It is desirable for the upper part -to be in the form of a small-diameter cylinder integral with the upper spring-plate, and for the lower part to be in the form of a larger-diameter rotating cylinder associated with the cylinder head. In this case, the valve-springs themselves may be arranged in-ternally or externally of the cylinders, without in any way affecting the opera=
tion of the valve-rotating device itself. This design is noted for its great stability and is also particularly simple to procluce.
In order to equalize the forces acting upon the rotating device, pro-vision is made, according to the invention, to arrange a plurality of ball-sockets and ball-grooves around the periphery of the cylinder and rotating cylinder. Depending upon the size of the valve, two, three, four, or more such "ball-bearings" may be provided, without substantially increasing the production costs of the valve-rotating device itself. ~niform Inovement is still further promoted in that the ball-grooves are helical with a constant pitch. The balls thus roll uniformly in the grooves during the rota~ing process and canno-t become jammed in any position.
The spring plates and rotating parts are usually made of the same material. It is desirable to design the upper spring plate and cylinder as a unit, in order to reduce production costs and improve dimensional accuracy.
In the case of large valves, lack of space or, more particularly, if the valve-rotating device is to be fitted to an existing engine, it may be de-sirable for the upper part to contain the ball-groove and for the lower part to be in the form of a rotating ring with sockets for the accomodation of the balls, the ring being arranged,together with the unidirectional clutch on the cylinder-head by means of a bearing-plate including both parts. [n this design the unidirectional clutch is arranged radially, thus ensuring satisfactory operation of the rotating device, even in compact designs.
In order to reduce inertia-forces and simplify incorporation, it is desirable, in the case of compact designs, for the bearing-plate, and for a bearing-washer resting upon the cylinder-head, to be secured to the cylinder-head by attachment screws, with a predeterminable amount of play. This provides simple, automatic centering of the parts during assembly.
Iurther improvement and simplification Or centering may be achieved, according to the invention, in that the edge of the bearing-plate associated with the upper part approaches the said upper part closely and is rounded off at least on one side.
Further reduction in inertia forces as the valve rotates may be ob-tained, according to the invention, by designing the upper part as a cylinder closely adjacent the valve-stem and screwed to the upper spring-plate.
The invention is noted for favourable mass-distribution, since only minor additional masses need by added at the top of the spring. In this area there are no unidirectional clutch, sliding connections, or the like, The unidirectional clutch or clutches is or are associated with the lower end of the valve-spring, together with the rotating part, thus eliminating all of the dis-advantages mentioned above. This makes it possible to fit such valve-rotating devices to high-speed engines also,even to those already produced ànd in oper-ation. It is furthermore advantageous for the rotational velocity of the valve to be largely adjustable by choice of the slope of the guide-slots, although this velocity is still also dependent upon engine r.p.m. This arrangement also en-sures a specific rotational velocity of the valve, even at very low engine r.p.m.
Fitting to existing engines is possible almost without altering the design of the engines, since individual parts of the valve-rotating device may be adapted to requirements. A reduction in weight may also be achieved by using light alloys.
Further development according to the invention reduces wear and con-centrates it upon a component which is easily removed and replaced. Since the load on the balls is at all times higher than that upon the ball grooves and i3 sockets, the said balls wear first. This effect may also be augmented ~y using for the balls a softer material than that used for the two cylinders of the ro-tating part. If any balls require replacement as a result of wear, the two cylinders may easily be moved apart.
In accordance with this invention there is provided a valve rotating device for an internal combustion engine having a cylinder head and valves, eEfective between a valve stem and the cylinder head, said device comprising:
an upper spring plate; a lower spring plate spaced along an axis below said upper plate and rotatable about said axis relative to said upper plate; a valve-spring braced axially between said plates; a two-part link element having an upper part rotationally secured to said stem and a lower part rotationally fixed in at least one rotational direction relative to said axis on said lower plate, said lower part being generally cylindrical, centered on said axis, fixed rotationally on said lower plate, and formed with a surface inclined to said axis, said upper part having a follower axially engageable with said surface;
and a unidirectional clutch between said lower plate and part and said cylinder head and permitting said lower part to rotate about said axis only in said one direction relative to said cylinder head, said lower part being a sleeve sur-rounding said spring and carried via said clutch on said cylinder head.
The invention will now be described in greater detail with reference to the accompanying drawings in which:
Figure 1 is a simplified representation of a valve-rotating device, in side elevation;
Figure 2 is a view similar to Figure 1 but showing another valve-rotating device, according to the invention;
Figure 3 is a part-section through the valve-rotating device accord-ing to Figure 2;
B
Figure 4 shows a section through the axis of symmetry of a third embodiment oE the valve-rotating device;
Figure 5 is a partial side elevation of the valve-rotating device according to Figure ~;
Figure 6 shows an enlarged detail of the valve rotating device accord-ing to Figure 1, in side elevation;
Figure 7 is a plan view of the detail in Figure 6;
Figure 8 is a part-section through the valve-rotating device accord-ing to Figure l;
Figure 9 is a fragmentary view showing a valve-rotating device accord-ing to the invention and having a ball-bearing guide; and Figure 10 is a view similar to Figure 9 but showing another type of valve-rotating device having a ball-bearing guide.
Figure 1 shows a rotating device for a valve marked 1 shown only in part. A valve-spring 2 is clamped between an upper spring-plate 3 and a lower spring-plate 4 and is positively connected to a unidirectional clutch 5 located under spring-plate 4. The latter is the rotating upper part of unidirectional clutch 5, the lower part of which is secured to cylinder-head 7. The upper part also carries a cylindr:ical rotating part 9 which acts as a guide and rotating part for valve 1.
Shown at upper edge 10 of the cylindrical rotating part is a guide-slot 11 which, in the embodiment illustrated, is in the form of a wedge-shaped recess 13 accommodating a pin 12. The latter is hinged to upper spring-plate 3 to which valve spring 2 and the unidirectional clutch 5 are positively connected.
Wedge-shaped recess 13 comprises edges 1~, 15, only edge 11~ being acted upon by pin 12 or pin-tip 16. ~his is achieved by preloading valve-spring 2. As shown in Figure 1, pin-tip 16 rubs against edge 14, damage and ~_ g _ 9~
loss of material being largely eliminated by the fact that both parts are hardened or coated with hard metal.
As valve 1 opens, and upper spring-plate 3 moves downwardly, the valve-plate is rotated in that tip 16 of pin 12 slides along edge 1~, but cannot rotate cylindrical rotating part 9 because this is locked by unidirectional clutch 5. This imparts a rotary motion to the upper spring-plate and, through the valve-stem, to the head of the valve. As the valve closes again and upper spring-plate 3 moves up, cylindrical rotating part 9 is moved in the direction of rotation, since this easily rotatable part is no longer locked by free-wheeling means 5, and this rotation of cylindrical part 9, and the forced rota-tion of valve-spring 2, causes the valve plate not shown to rotate.
At high engine r.p.m., this procedure takes place at such a speed that cylindrical rotating part 9 and the valve-plate rotate almost continuously in direction 17 of rotation.
In the valve-rotating device according to Figures 2 and 3, no torsion is applied to valve-spring 2. To this end, the latter is connected to a~ial bearing 21 arranged upon free-wheeling means 22. As may be seen in Figure 3, - 9a -B
i3 therefore, cam 20, which constitutes the tip of pin 12, is guided positively in slot 19.
As in the design according to Figures 4 and 5, upper spring-plate 3, and therefore valve-stem 23 and the valve-plate not shown, are rotated in that, as the said spring plate moves down, cam 20 is guided obliquely downwards in slot 19. Since cylindrical rotating part 9 is prevented from rotating in the opposite direc-tion by free-wheeling means 22, spring-plate 3 must rotate by thecorresponding amount. When spring-plate 3 moves up again, cylindrical rotating part 9 is moved in the direction of rotation, since this easily rotatable part is no longer locked by free-wheeling means 22.
The designs described may also be used with the free-wheeling means acting in the opposite direction. In this case, when valve 1 opens9 the free-wheeling means with the rotating part rotates first of all. Under otherwise similar conditions, the rotational velocity of the valve is lower with the free-wheeling means acting in this direction.
In the design according to Figures 4 and 5, the cylindrical rotating par-t is arranged as part 24 within valve spring 2. Here again, cams 20, 26 on pins 12, 25 are guided positively in oblique slot 27 which allows the afore-said rotational forces to act upon valve-stem 23.
As indicated, upper spring-plate 3 is connected by pins or the like to valve-stem 23, so that forces acting upon the said spring-plate also act ~r~ upon the said valve-stem and upon tlle valve-plate not shown.
~a~
Figures 6 and 7 ~4~-edge 14 fitted with a hard-metal pin 30, the said pin being inserted into pilot-hole 31 of recess 13 and being then secured to the wall of cylindrical rotating part 9 by cementing, gluing, or by some other means. As may be gathered from Figure 7, pilot-hole 31 is drilled at a specific angle, so that the subsequently fitted hard-metal pin allows pin-tip :.
16 to roll satisfactorily thereon. In the design of pin-tip 16 illustrated in Figure 8, this rolling motion takes place almost without friction, in that a ball-bearing 34 is located in the vicinity of the said tip and rotates about an axis 35 which is thus at right angles to valve-stem 23 and the axis of the valve.
The valve-spring and free-wheeling means are not shown in Figure 9.
Arranged at upper edge 10 of part 29, constituting rotating cylinder 41, is a sloping or helical groove 38 for a ball 36 located in a ball-socket 37 in upper part 28, in the form of cylinder 40, of rotating part 9.
As valve 1 opens and upper spring-plate 3 moves down~ardly with valve-]0 stem 23, spring-plate 3 is rotated in that ball 36 travels in groove 37 but ls unable to move rotating cylinder 41, since the latter is locked in this direc-tion of rotation by the free-wheeling means, not shown. Upper spring-plate 3 is therefore caused to rotate, the degree of rotation being a function of the slope of ball-groove 38. During this movement, ball 36 rolls in socket 37 and in groove 38, so that wear is scarcely possible. Such wear is still further minimized in that oil or lubricant emerges during the up and down movements of the valve, thus lubricating this "ball-bearing".
B As valve 1 closes, and upper spring-plate 3 moves ~
cylinder 41 also rotates, i.eO moves with them, since this easily rotatable part is not locked in this direction by the free-wheeling means.
With the free-wheeling means acting in the opposite direction, the movements are reversed, i.e. cylinder 41 rotates when the valve opens and pulls valve-stem 23 behind it when the valve closes.
Thus each time valve-stem 23 moves up and down, th& said stem, and therefore the valve, is rotated by a specific amount depending upon engine r.p.m., thus assuring uniform loading of the seat.
The valve-rotating device according to Figure 10 operates upon the same principle. In this case helical ball-groove 38 is associated with upper part 28 closely adjacent valve-stem 23, while ball-socket 37 and ball 36 are a.ssociated with a rotating ring 42. Upper part 28 is in the form of a cylinder 40 screwed to upper spring-plate 3.
Rotating ring 42J and free-wheeling means 22~ are held to cylinder-head 7 by bearing-plate 43 and bearing washer 44. In addition to the locking elements, free-wheeling means 22 comprises a radial roller-bearing.
Bearing-plate 43 is used to secure rotating ring 42 and free-wheeling means 22, the bearing-plate being retained resiliently by attachment screws 45.
This is achieved by means of Belleville springs 49 which bear upon plate 43 and,through a washer 50, upon the heads o:f screws 45. In order to simplify assembly, long shank 47 is screwed into cylinder-head 7 by means of an inside hexagon 48.
Belleville springs 49, the force of which is greater than the axial forces exerted by balls 36 in the drive, provide parts 22, 42, 43 and 44 with enough play to permit centering when the valve is assembled. At this time, bearing plate 42 is automatically centered by its edge 51 and by cylinder 40.
Centering may also be carried out by rotating ring 42. In any case, balls 36 must be inserted into ball-sockets 37 before actual assembly of the valve.
Depending upon the direction of the free-wheeling means and the direc-tion of rotation of spiral ball-grooves 38 in cylinder 40, ring 42 rotates during the upward or downward strolce or is held by the said free-wheel:ing means, so that valve 1 co-rotates only by a specific amount.
A valve-rotating device of this kind is known in principle (German OS 28 ~1 ~89) which was published on 23.09.1978 in the name of Blohm v. Voss, AG.
The known valve-rotating device makes use of the twisting of a helical spring as it is loaded and unloaded, in conjunction with a free-wheeling means, e.g. a one-way clutch, to produce stepwise rotation of the valve. In this case, a free-wheeling means is associated with each of the two concentrically arranged helical springs, the turns of which are wound in opposite directions. The two free-wheeling means both lock in the same direction. Thus each time the valve opens and closes, each of the two springs is acted upon in such a manner that, with opposing movement of the valve stepwise rotation thereof occurs. The dis-advantage of this arrangement is that the rotational velocity of the valve is de-pendent mainly upon engine r.p.m. Thus at low camshaft r.p.m., the valve rotates only in very small steps or not at all. Furthermore, the rotary motion is de-pendent upon a very wide variety of factors, such as fric-tional torque in the valve guide, mass inertia moment, and the like, which have different effects at different rotational velocities.
In addition to the foregoing are various proposals ~German AS 19 55 820 published on 2~.09.1963 in the name of Tewes-Thompson GmbH German AS 21 10 708 published on 05.03.1971 in the name of Tewes-Thomspon GmbH German OS 21 16 086 published on 02.0~.1971 in the name of Tewes-Thompson GmbH German OS 26 40 383 publlshed on 09.09.1976 in the name of Tewes-Thompson GmbH German OS 27 57 ~55 published on 22.12.1977 in the name of TRW. Inc.) using rolling or sliding -r- E 1398 5~
elements, in pockets having sloping planes arranged concentrically around the axis of a base-element, which are loaded by tangentially acting springs adapted to be compressed, when the rolling or sliding elements are loaded, in the direc-tion of the flat sides of the pockets. They co-opera-te with a spring-element which tensions itself in the axial direction of the valve, the rolling or sliding elements being unloaded in the axial direction of the valve as the tension of the said spring-element increases, and being unloaded as the tension of the spring-element decreases, to produce relative rotation between the base-element and thespring-element. ~y using sloping planes having dif:Eerent configurations and different slopes, and equipped with differen~ rolling and sliding elements, at-tempts have been made to cause the rolling elements to travel as uniformly as possible in the peripheral direction, and thus to impart a uniform rotary motionto the valve. All of these valve-rotating devices are characteri~ed by a plur-ality oE individual parts, springs possessing different properties, and limited ability to rotate the valve. In view of the complexity of the design, suffi-ciently reliable operation is not assured.
In view of the foregoing disadvantages, attempts have also been made to achieve uniform rotation of the valve by means of positive controls associated with the engine-block. The disadvantage of this is that these positive controls act upon the respective upper spring-plates. This results in an expensive designwhich is difficult to fit to existing engines because of the large amount of space required, and which cannot be used with high-speed engines ~German OS 20 54 351 published on 05.11.1970 in the name of H. D. Klockner, et al; 21 28 110 published on 05.06.1971 in the name of H. D. Klockner, et al; 20 54 349 published on 05.11.1970 in the name of H. D. Klockner, et al; 20 54 362 published on ~49~5~
05.11.1970 in the name of ~I. D. Klockner, et al; and 27 39 403 published on 01.09.1977 in the name of ~I. D. Klockner, et al).
It is the purpose of the invention to provide a valve-rotating device which may be applied to both high and low-speed engines, which at all times en-sures adequate valve-rotation without rotating the springs, and which is as free as possible from wear.
According to the invention, this purpose is achieved in that a two-part rotating element is arranged between the upper and lower spring-plates, the two parts engaging with each other and rotating with the valve, the lower part being connected to the cylinder-head through the unidirectional clutch, and the upper part being connected to the upper spring-plate.
In this connection, it is desirable for the cylindrical rotating part to be associated with the unidirectional clutch positively connected to the valve-spring, the rotating part comprising guide-slots for the pin constituting the upper part.
In the valve-rotating device of this kind, the mechanism which rotates the valve is colmected to the unidirectional clutch and therefore rotates with the valve. The system is moreover designed in such a manner that rotation of the valve is always achieved, even at low engine r.p.m., dependently upon the mass inertia moments of the unidirectional clutch and the rotating part, and upon fric-tional torque in the valve-guide. By dispensing with purely -positive control, which inevitably takes up substantially more space, and by associating the part which rotates the valve with the unidirectionalclutch arranged upon the lower spring-plate, optimal use is made of the available space and any change or weight increase in the vicinity of the upper spring-plate is almost completely avoided.
This makes it possible to use a valve-rotating device of this kind in high-speed engines also, and to achieve high rotational velocities of the valve.
_3 5i3 Wear between the pin and the guide slot, which rub against each other~
is preferably limited in that the guide-slots are in the form of wedge-shaped recesses, the edges thereof which come into contact with the pin being hardened.
According to one design, the edges and the tip of the pin are coated with hard metal. This prevents damage even under the heaviest loads; wear is further minimized by the presence in this area of engine-oil.
The magnitude of the rotary motion of the valve during each cycle is predetermined by the slope of the guide-slot or recess. It has been found that optimal rotary motion of the valve is assured, even at different velocities, if the two parts of the rotating device turn in relation to each other by between 6 and 12 at each valve-stroke.
In the case of high-speed engines in particular, it may be desirable B to provide the ~-p of the pin with a ball-bearing adapted to rotate about an axis at right angles to the valve-stem. A design of this kind also largely eliminates frictional losses. Here again, the oil in this area also assists in lubricating the ball-bearing.
An advantageous example of embodiment of the invention, from the point of view of weight, provides for the rotating device to be arranged within the valve-spring and to have, at its upper edge, a sloping slot which guides the pin or cam. Here again, valve-spring torsion is used to produce subsequent rotary motion of the valve itself.
According to the invention, valve-spring torsion may be dispensed with if, with a rotating part comprising a closed gap, the valve-spring is mounted to rotate freely, in the vicinity of the lower spring-plate, by means of an axial bearing. In this design, only the gap in the rotating part, and thus the rotat-ing part itself, produces rotation of the valve and valve-plate.
In order to be able to use the vertical motion of the valve, both in s~
opening and closing, to rotate the valve-plate, provision is made, according to the invention, for a rotating part with a gap also to be arranged outside the valve-spring, and for a separate unidirectional clutch, acting in the same direc tion, to be associated therewith. If two such rotating mechanisms, with separate unidirectional clutch, are used for a single valve, -the masses to be moved are again kep-t small, in that one of the rotating parts is arranged outside and the other inside the valve-spring. In this collnection it is desirable for the slop-ing slot in the inner,and the gap inthe outer, rotating part to run in opposite directions, and to have a different inclination. As a result of this, the valve is rotated both when it opens and when it closes, and the rotational veloci-ty upon opening may differ from that upon closing, depending upon the slope of each gap. The two unidirectional clutch act in the same direction, i.e. they lock and rotate in the same direction of rotation.
Further substantial reduction in wear is achieved in that the upper and lower parts of the valve-rotating device are arranged close together as they move in relation to each other, and are connected together by balls which rotate, the said balls being guided in the upper part in a ball-socket and, in the lower part, in a ball-groove running obliquely downwards. A device of this kind rotates at a higher r.p.m., and more reliably, than e~isting rotating devices. The balls in no way affect this rotation and thus cause little wear. Furthermore, since any wear arising occurs in the balls themselves, these can be replaced whersupon the valve-rotating device becomes fully serviceable again without replacing or rework;ng any other parts. If any wear occurs, replacement is a simple matter and takes little time.
It is desirable for the upper part -to be in the form of a small-diameter cylinder integral with the upper spring-plate, and for the lower part to be in the form of a larger-diameter rotating cylinder associated with the cylinder head. In this case, the valve-springs themselves may be arranged in-ternally or externally of the cylinders, without in any way affecting the opera=
tion of the valve-rotating device itself. This design is noted for its great stability and is also particularly simple to procluce.
In order to equalize the forces acting upon the rotating device, pro-vision is made, according to the invention, to arrange a plurality of ball-sockets and ball-grooves around the periphery of the cylinder and rotating cylinder. Depending upon the size of the valve, two, three, four, or more such "ball-bearings" may be provided, without substantially increasing the production costs of the valve-rotating device itself. ~niform Inovement is still further promoted in that the ball-grooves are helical with a constant pitch. The balls thus roll uniformly in the grooves during the rota~ing process and canno-t become jammed in any position.
The spring plates and rotating parts are usually made of the same material. It is desirable to design the upper spring plate and cylinder as a unit, in order to reduce production costs and improve dimensional accuracy.
In the case of large valves, lack of space or, more particularly, if the valve-rotating device is to be fitted to an existing engine, it may be de-sirable for the upper part to contain the ball-groove and for the lower part to be in the form of a rotating ring with sockets for the accomodation of the balls, the ring being arranged,together with the unidirectional clutch on the cylinder-head by means of a bearing-plate including both parts. [n this design the unidirectional clutch is arranged radially, thus ensuring satisfactory operation of the rotating device, even in compact designs.
In order to reduce inertia-forces and simplify incorporation, it is desirable, in the case of compact designs, for the bearing-plate, and for a bearing-washer resting upon the cylinder-head, to be secured to the cylinder-head by attachment screws, with a predeterminable amount of play. This provides simple, automatic centering of the parts during assembly.
Iurther improvement and simplification Or centering may be achieved, according to the invention, in that the edge of the bearing-plate associated with the upper part approaches the said upper part closely and is rounded off at least on one side.
Further reduction in inertia forces as the valve rotates may be ob-tained, according to the invention, by designing the upper part as a cylinder closely adjacent the valve-stem and screwed to the upper spring-plate.
The invention is noted for favourable mass-distribution, since only minor additional masses need by added at the top of the spring. In this area there are no unidirectional clutch, sliding connections, or the like, The unidirectional clutch or clutches is or are associated with the lower end of the valve-spring, together with the rotating part, thus eliminating all of the dis-advantages mentioned above. This makes it possible to fit such valve-rotating devices to high-speed engines also,even to those already produced ànd in oper-ation. It is furthermore advantageous for the rotational velocity of the valve to be largely adjustable by choice of the slope of the guide-slots, although this velocity is still also dependent upon engine r.p.m. This arrangement also en-sures a specific rotational velocity of the valve, even at very low engine r.p.m.
Fitting to existing engines is possible almost without altering the design of the engines, since individual parts of the valve-rotating device may be adapted to requirements. A reduction in weight may also be achieved by using light alloys.
Further development according to the invention reduces wear and con-centrates it upon a component which is easily removed and replaced. Since the load on the balls is at all times higher than that upon the ball grooves and i3 sockets, the said balls wear first. This effect may also be augmented ~y using for the balls a softer material than that used for the two cylinders of the ro-tating part. If any balls require replacement as a result of wear, the two cylinders may easily be moved apart.
In accordance with this invention there is provided a valve rotating device for an internal combustion engine having a cylinder head and valves, eEfective between a valve stem and the cylinder head, said device comprising:
an upper spring plate; a lower spring plate spaced along an axis below said upper plate and rotatable about said axis relative to said upper plate; a valve-spring braced axially between said plates; a two-part link element having an upper part rotationally secured to said stem and a lower part rotationally fixed in at least one rotational direction relative to said axis on said lower plate, said lower part being generally cylindrical, centered on said axis, fixed rotationally on said lower plate, and formed with a surface inclined to said axis, said upper part having a follower axially engageable with said surface;
and a unidirectional clutch between said lower plate and part and said cylinder head and permitting said lower part to rotate about said axis only in said one direction relative to said cylinder head, said lower part being a sleeve sur-rounding said spring and carried via said clutch on said cylinder head.
The invention will now be described in greater detail with reference to the accompanying drawings in which:
Figure 1 is a simplified representation of a valve-rotating device, in side elevation;
Figure 2 is a view similar to Figure 1 but showing another valve-rotating device, according to the invention;
Figure 3 is a part-section through the valve-rotating device accord-ing to Figure 2;
B
Figure 4 shows a section through the axis of symmetry of a third embodiment oE the valve-rotating device;
Figure 5 is a partial side elevation of the valve-rotating device according to Figure ~;
Figure 6 shows an enlarged detail of the valve rotating device accord-ing to Figure 1, in side elevation;
Figure 7 is a plan view of the detail in Figure 6;
Figure 8 is a part-section through the valve-rotating device accord-ing to Figure l;
Figure 9 is a fragmentary view showing a valve-rotating device accord-ing to the invention and having a ball-bearing guide; and Figure 10 is a view similar to Figure 9 but showing another type of valve-rotating device having a ball-bearing guide.
Figure 1 shows a rotating device for a valve marked 1 shown only in part. A valve-spring 2 is clamped between an upper spring-plate 3 and a lower spring-plate 4 and is positively connected to a unidirectional clutch 5 located under spring-plate 4. The latter is the rotating upper part of unidirectional clutch 5, the lower part of which is secured to cylinder-head 7. The upper part also carries a cylindr:ical rotating part 9 which acts as a guide and rotating part for valve 1.
Shown at upper edge 10 of the cylindrical rotating part is a guide-slot 11 which, in the embodiment illustrated, is in the form of a wedge-shaped recess 13 accommodating a pin 12. The latter is hinged to upper spring-plate 3 to which valve spring 2 and the unidirectional clutch 5 are positively connected.
Wedge-shaped recess 13 comprises edges 1~, 15, only edge 11~ being acted upon by pin 12 or pin-tip 16. ~his is achieved by preloading valve-spring 2. As shown in Figure 1, pin-tip 16 rubs against edge 14, damage and ~_ g _ 9~
loss of material being largely eliminated by the fact that both parts are hardened or coated with hard metal.
As valve 1 opens, and upper spring-plate 3 moves downwardly, the valve-plate is rotated in that tip 16 of pin 12 slides along edge 1~, but cannot rotate cylindrical rotating part 9 because this is locked by unidirectional clutch 5. This imparts a rotary motion to the upper spring-plate and, through the valve-stem, to the head of the valve. As the valve closes again and upper spring-plate 3 moves up, cylindrical rotating part 9 is moved in the direction of rotation, since this easily rotatable part is no longer locked by free-wheeling means 5, and this rotation of cylindrical part 9, and the forced rota-tion of valve-spring 2, causes the valve plate not shown to rotate.
At high engine r.p.m., this procedure takes place at such a speed that cylindrical rotating part 9 and the valve-plate rotate almost continuously in direction 17 of rotation.
In the valve-rotating device according to Figures 2 and 3, no torsion is applied to valve-spring 2. To this end, the latter is connected to a~ial bearing 21 arranged upon free-wheeling means 22. As may be seen in Figure 3, - 9a -B
i3 therefore, cam 20, which constitutes the tip of pin 12, is guided positively in slot 19.
As in the design according to Figures 4 and 5, upper spring-plate 3, and therefore valve-stem 23 and the valve-plate not shown, are rotated in that, as the said spring plate moves down, cam 20 is guided obliquely downwards in slot 19. Since cylindrical rotating part 9 is prevented from rotating in the opposite direc-tion by free-wheeling means 22, spring-plate 3 must rotate by thecorresponding amount. When spring-plate 3 moves up again, cylindrical rotating part 9 is moved in the direction of rotation, since this easily rotatable part is no longer locked by free-wheeling means 22.
The designs described may also be used with the free-wheeling means acting in the opposite direction. In this case, when valve 1 opens9 the free-wheeling means with the rotating part rotates first of all. Under otherwise similar conditions, the rotational velocity of the valve is lower with the free-wheeling means acting in this direction.
In the design according to Figures 4 and 5, the cylindrical rotating par-t is arranged as part 24 within valve spring 2. Here again, cams 20, 26 on pins 12, 25 are guided positively in oblique slot 27 which allows the afore-said rotational forces to act upon valve-stem 23.
As indicated, upper spring-plate 3 is connected by pins or the like to valve-stem 23, so that forces acting upon the said spring-plate also act ~r~ upon the said valve-stem and upon tlle valve-plate not shown.
~a~
Figures 6 and 7 ~4~-edge 14 fitted with a hard-metal pin 30, the said pin being inserted into pilot-hole 31 of recess 13 and being then secured to the wall of cylindrical rotating part 9 by cementing, gluing, or by some other means. As may be gathered from Figure 7, pilot-hole 31 is drilled at a specific angle, so that the subsequently fitted hard-metal pin allows pin-tip :.
16 to roll satisfactorily thereon. In the design of pin-tip 16 illustrated in Figure 8, this rolling motion takes place almost without friction, in that a ball-bearing 34 is located in the vicinity of the said tip and rotates about an axis 35 which is thus at right angles to valve-stem 23 and the axis of the valve.
The valve-spring and free-wheeling means are not shown in Figure 9.
Arranged at upper edge 10 of part 29, constituting rotating cylinder 41, is a sloping or helical groove 38 for a ball 36 located in a ball-socket 37 in upper part 28, in the form of cylinder 40, of rotating part 9.
As valve 1 opens and upper spring-plate 3 moves down~ardly with valve-]0 stem 23, spring-plate 3 is rotated in that ball 36 travels in groove 37 but ls unable to move rotating cylinder 41, since the latter is locked in this direc-tion of rotation by the free-wheeling means, not shown. Upper spring-plate 3 is therefore caused to rotate, the degree of rotation being a function of the slope of ball-groove 38. During this movement, ball 36 rolls in socket 37 and in groove 38, so that wear is scarcely possible. Such wear is still further minimized in that oil or lubricant emerges during the up and down movements of the valve, thus lubricating this "ball-bearing".
B As valve 1 closes, and upper spring-plate 3 moves ~
cylinder 41 also rotates, i.eO moves with them, since this easily rotatable part is not locked in this direction by the free-wheeling means.
With the free-wheeling means acting in the opposite direction, the movements are reversed, i.e. cylinder 41 rotates when the valve opens and pulls valve-stem 23 behind it when the valve closes.
Thus each time valve-stem 23 moves up and down, th& said stem, and therefore the valve, is rotated by a specific amount depending upon engine r.p.m., thus assuring uniform loading of the seat.
The valve-rotating device according to Figure 10 operates upon the same principle. In this case helical ball-groove 38 is associated with upper part 28 closely adjacent valve-stem 23, while ball-socket 37 and ball 36 are a.ssociated with a rotating ring 42. Upper part 28 is in the form of a cylinder 40 screwed to upper spring-plate 3.
Rotating ring 42J and free-wheeling means 22~ are held to cylinder-head 7 by bearing-plate 43 and bearing washer 44. In addition to the locking elements, free-wheeling means 22 comprises a radial roller-bearing.
Bearing-plate 43 is used to secure rotating ring 42 and free-wheeling means 22, the bearing-plate being retained resiliently by attachment screws 45.
This is achieved by means of Belleville springs 49 which bear upon plate 43 and,through a washer 50, upon the heads o:f screws 45. In order to simplify assembly, long shank 47 is screwed into cylinder-head 7 by means of an inside hexagon 48.
Belleville springs 49, the force of which is greater than the axial forces exerted by balls 36 in the drive, provide parts 22, 42, 43 and 44 with enough play to permit centering when the valve is assembled. At this time, bearing plate 42 is automatically centered by its edge 51 and by cylinder 40.
Centering may also be carried out by rotating ring 42. In any case, balls 36 must be inserted into ball-sockets 37 before actual assembly of the valve.
Depending upon the direction of the free-wheeling means and the direc-tion of rotation of spiral ball-grooves 38 in cylinder 40, ring 42 rotates during the upward or downward strolce or is held by the said free-wheel:ing means, so that valve 1 co-rotates only by a specific amount.
Claims (18)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A valve rotating device for an internal combustion engine having a cylinder head and valves, effective between a valve stem and the cylinder head, said device comprising:
an upper spring plate;
a lower spring plate spaced along an axis below said upper plate and rotatable about said axis relative to said upper plate;
a valve-spring braced axially between said plates;
a two-part link element having an upper part rotationally secured to said stem and a lower part rotationally fixed in at least one rotational direction relative to said axis on said lower plate, said lower part being generally cylindrical, centered on said axis, fixed rotationally on said lower plate, and formed with a surface inclined to said axis, said upper part having a follower axially engageable with said surface; and a unidirectional clutch between said lower plate and part and said cylinder head and permitting said lower part to rotate about said axis only in said one direction relative to said cylin-der head, said lower part being a sleeve surrounding said spring and carried via said clutch on said cylinder head.
an upper spring plate;
a lower spring plate spaced along an axis below said upper plate and rotatable about said axis relative to said upper plate;
a valve-spring braced axially between said plates;
a two-part link element having an upper part rotationally secured to said stem and a lower part rotationally fixed in at least one rotational direction relative to said axis on said lower plate, said lower part being generally cylindrical, centered on said axis, fixed rotationally on said lower plate, and formed with a surface inclined to said axis, said upper part having a follower axially engageable with said surface; and a unidirectional clutch between said lower plate and part and said cylinder head and permitting said lower part to rotate about said axis only in said one direction relative to said cylin-der head, said lower part being a sleeve surrounding said spring and carried via said clutch on said cylinder head.
2. A valve-rotating device according to claim 1, characterized in that the lower part includes a guide-slot receiving the upper part which is in the form of a pin.
3. A valve-rotating device according to claim 2, charac-terized in that the guide-slot is in the form of a wedge-shaped recess, the edges of which are acted upon by the pin, which is hardened or coated with hard metal.
4. A valve-rotating device according to claim 1, charac-terized in that the two parts of the link element rotate through 6 - 12° in relation to each other during each stroke of the valve.
5. A valve-rotating device according to claim 3, charac-terized in that a ball-bearing is associated with the tip of the pin, the ball-bearing being adapted to rotate about an axis at right angles to the valve-stem.
6. A valve-rotating device according to claim 1, charac-terized in that the upper rotating part of the two-part link element is arranged within the valve-spring and carries at its upper edge a sloping slot which guides a pin or cam.
7. A valve-rotating device according to claim 6, charac-terized in that the valve-spring is mounted, in the vicinity of the lower spring-plate, to rotate freely by means of an axial bearing.
8. A valve-rotating device according to claim 6, charac-terized in that the upper rotating part with the slot is arranged externally of the valve-spring and is associated with a separate unidirectional clutch acting in the same direction.
9. A valve-rotating device according to claim 8, charac-terized in that the sloping slot in the upper rotating part and the slot in the lower rotating part, run in opposite directions and have different inclinations.
10. A valve-rotating device according to claim 1, charac-terized in that the upper and lower parts are designed to move closely past each other and are connected together by rotatably arranged balls, the balls in the upper part being guided in a ball-socket and those in the lower part being guided in a ball-groove running obliquely downwards.
11. A valve-rotating device according to claim 10, charac-terized in that the upper part is in the form of a smaller-diameter cylinder integral with the upper spring-plate, while the lower part is in the form of a larger-diameter rotating cylin-der associated with the cylinder-head.
12. A valve-rotating device according to claim 11, charac-terized in that a plurality of ball-sockets and ball-grooves is distributed around the periphery of the cylinder and of the rotat-ing cylinder.
13. A valve-rotating device according to claim 10, characterized in that the ball-grooves are helical with a constant pitch.
14. A valve-rotating device according to claim 10, characterized in that the upper spring-plate and the cylinder constitute a single component.
15. A valve-rotating device according to claim 10, characterized in that the upper part carries the ball-grooves, while the lower part is in the form of a rotating ring which comprises grooves for the accommodation of the balls, and which is arranged, together with the inidirectional cluth, by means of a bearing-plate accommodating both components, upon the cylinder-head.
16. A valve-rotating device according to claim 15, characterized in that the bearing-plate, and a bearing washer resting upon the cylinder-head, are connected to the cylinder-head with a predeterminable amount of play, by means of attachment screws.
17. A valve-rotating device according to claim 15, characterized in that an edge of the bearing-plate, associated with the upper part, is designed to be in close proximity with the said upper part and is rounded at least on one side.
18. A valve-rotating device according to claim 15, characterized in that the upper part is in the form of a cylinder which fits closely to the valve-stem and which is screwed to the upper spring-plate
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3029988.8 | 1980-08-08 | ||
| DE19803029988 DE3029988C2 (en) | 1980-08-08 | 1980-08-08 | Valve rotating device |
| DEP3113944.2 | 1981-04-07 | ||
| DEP3128086.2 | 1981-07-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1184453A true CA1184453A (en) | 1985-03-26 |
Family
ID=6109134
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000383478A Expired CA1184453A (en) | 1980-08-08 | 1981-08-07 | Valve-rotating device |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS57113917A (en) |
| CA (1) | CA1184453A (en) |
| DE (1) | DE3029988C2 (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1520272A (en) * | 1920-06-23 | 1924-12-23 | Continental Engineering Corp | Valve-rotating mechanism |
| US1610409A (en) * | 1922-09-25 | 1926-12-14 | Continental Engineering Corp | Brake |
-
1980
- 1980-08-08 DE DE19803029988 patent/DE3029988C2/en not_active Expired
-
1981
- 1981-08-04 JP JP12149081A patent/JPS57113917A/en active Granted
- 1981-08-07 CA CA000383478A patent/CA1184453A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE3029988A1 (en) | 1982-04-08 |
| JPS57113917A (en) | 1982-07-15 |
| DE3029988C2 (en) | 1982-12-30 |
| JPS6244085B2 (en) | 1987-09-18 |
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| Date | Code | Title | Description |
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| MKEX | Expiry |