US2190900A - Motion transmitting mechanism - Google Patents

Description

Patented Feb. 20, 1940 nsect PATENT OFFHQE MOTION TRANSMITTING MECHANISM Hesper von Tavcl, Soleure, Switzerland, assignor to Scintilla Ltd, Soleure, Switzerland, a corporation of Switzerland Application April 4, 1938, Serial No. 200,049 in Switzerland April 5, 1937 ll Claims.

This invention relates to a motion transmitting mechanism including a fluid-pressure responsive, angularly adjustable shaft coupling ,device. in particular, though not exclusively, such mechanism may be used for driving auxiliary apparatus, such as fuel injection pumps, ignition apparatus, valve gear and the like, cooperating with internal combustion engines, the fluid-pressure responsive, angularly adjustable shaft coupling device then serving for varying the timing of the operation of such auxiliary apparatus in relation to the working cycle of the internal combustion engine.

One of the objects of my invention is to provide a simple and compact arrangement of the said mechanism, in which no linkage rods or levers are required for adjusting the said shaft coupling device.

Another object of the invention is to arrange the parts so as to diminish the possibilities of leakage of the pressure-fluid supplied for adjusting the said shaft coupling device.

The invention further has for its purpose to provide a construction in which the said fluidpressure is supplied to the angularly adjustable shaft coupling device through means well protected from. accidental damage.

Further objects and advantages of my invention will appear from the following description of embodiments thereof with reference to the accompanying drawings, and. it will beunderstood that while I have described what may be consid ered as preferable embodiments of my invention, 1 do not limit myself to the precise conditions or proportions herein set forth, as they may be varied by those skilled in the art in accordance with the particular purposes for which they are intended, and theco nditions under which they are to be utilized.

In the said drawings,

Fig. 1 is a longitudinal section through a fuel injection pump for internal combustion engines, and through its injection timing device embodying the invention. a

Fig. 2 is a cross-section on the line AA of Fig. 1.

Fig. 3 shows, also in longitudinal section, an

adjustable shaft coupling suitable for replacing exactly similar to the corresponding parts shown a in Fig. 1.

Fig. 4 is a longitudinal section through a fuel injection pump and injection timing device, in

which the invention is embodied still in another Fig. 5 is a horizontal section on the line 13-13 of Fig. 4. i

In the embodiment shown in Figs. 1 and 2, the reference number tilt indicates generally the fuel injection pump of a three-cylinder internal combustion engine; t is the housing of the said pump, and 3 is the cam shaft supported in the ball bearings l and 2 lodged in the housing 1. The cam shaft 3 has three cams Nil, I02 and M3 formed thereon and each actuating one piston of the feul injection pump through a pusher HM, M5, [06

carrying a loose roller such as lll'l on a journal Hi8, and guided in the housing 4. Springs I09, ill? and ill are provided for pressing the pushers lil i, Hi5 and tilt home onto their actuating cams let, it? and IE3. As the fuel injection pump Hi may operate on any suitable principle and does not form a part of the present invention, its cylinders, pistons, valves and similar parts have not been shown in the drawing and need not be described; they are concealed in the upper portion of the housing l, from which injection conduits l [2, H3 and lit lead to the cylinders of the internal combustion engine, which are not shown. is a housing fixed to the pump housing 4 and enclosing the adjustable coupling device. A

further ball bearing 6 lodged in the housing 5 supports the driving member 7!, to which a cover piece 8 is secured by screws 8a. The cover piece 8 is rotatably supported on the cam shaft 3 next to the bearing l. The driving member l is keyed to a shaft 9 driven from the internal combustion engine in a way not shown and has a cylindric t and thepiston ll presses the latter into the cylindric recess ll].

At the other end of the injection pump, where its camshaft is supported by the bearing 2, the casing i9 of a gear pump is fixed to the injection pump housing 4. Said pump comprises a gearwheel ill which is keyed to the cam shaft 3 and which meshes with a second gearwheel 22 journalled on the pin 2!. Both said gearwheels tightly fit the gear pump casing 19 on their faces and on a considerable portion of their circumference, so that when driven as indicated by the arrow they displace'liquid from the supply chamber 23 to the delivery chamber 25. The supply chamber 23 is connected to a reservoir (not shown) by a supply pipe 24. From the delivery chamber 25 a duct 26 leads to a restricted passage 21 whose cross-section may be adjusted by means of the adjusting screw 28, and a conduit 29 is connected after said passage 21 for carrying the liquid away. In the conduit 29, the liquid pressure will suitably be kept substantially constant by a pressure regulating device which-may comp-rise a spring-loaded piston valve acted upon by the liquid pressure in the conduit 29 and controlling a release passage.

The liquid supplied to the described system from the reservoir may be lubricating oil, glyc-.

which bore the pressure of the liquid is trans mitted from the gear pump to the pressure-responsive adjustable coupling 'at the other end of the injection pump. The ducttt issues in the plane inner face 32 of the gear pump casing l9, opposite the end face of the cam shaft 3. A

short flanged tube 33 communicating with the bore 3! of the cam shaft 3 has on its flange a plane end face tightly fitting the face 32 of the casing l9 and pressed thereto by a spring 34. "The latter abuts the flange of another short tube I 35 in which the tube 33 is a slidable tight fit, and

presses .said tube 35 against a ring 38 having a spherical face-fitting a corresponding recess in the'end face of the cam shaft 3. The connec- 7 tion thus established between the duct Eli and the bore 3! allows for free movement of the cam shaft 3. On. account of the spherical fitting surfaces of the ring tit-with the camshaft 3 and because the flange of the tube 33 can slide along the piston H though angularly movable with relation to the axis of the latter, as the said tube 31 has a spherical head 38 which is confined by the cup 39 forced into a recess of the piston II. The tube 31 is guided in a bore of the ball 41], which is retained in a spherical recess of the cam shaft 3 by a cup M forced into said recess.

When the internal combustion engine is running, the driving shaft 9, the driving member 1, and the cover piece 8 rotate together. The tubular extension if being angularly coupled to the jection pump. The cam shaft 3 also drives the gear pump 2%,122, which displaces from the supply chamber 23 to the delivery chamber 25 a quantity of liquid increasing according to the sense of rotation of the said cam shaft.

in Fig. 3.

number of revolutions of the cam shaft 3. From the delivery chamber 25, the liquid flows off through the duct 26 and the restricted passage 2?, and thence through the conduit 29. Because of the throttling effect in the restricted passage 21 the liquid pressure in the duct 26 increases approximately according to the square of the angular speed of the cam shaft 3. This liquid pressure is transmitted to the cylindricrecess l through the duct Sll, the tube 33, the bore 3! of the cam shaft 3, and the tube 31. As the angular speed of the cam shaft 3 increases, the increasing liquid pressure in the recess lfl displaces the piston ll against the force of the spring 16. As the said piston and its extension l2 are guided by the quick pitch thread It engaging cover piece 83 carried by the driving member 1, they are angularly displaced relatively to the latter while proceeding under the effect of the liquid pressure, and as the splines it are in engagement with the slots [4 of the cam shaft 3, the latter must follow this angular displacement. The quick pitch thread I is directed in such a way that when the pressure in the recess Ill increases the angular displacement of the shaft 3 relatively to the member 1 takes place in the Thus the fuel injection by the injection pump is advanced when the internal combustion engine runs faster, and delayed when it runs slower. Such a variation of the injection timing is known to have a good influence on the steady running of the internal combustion engine at all speeds.

In the embodiment shown in Fig. 3 a cylinder 53 is carried by the end of shaft 3, to which it is angularly coupled by a pin 5! and fixed by the nut 52. The piston 54 is a tight fit in the cylinder 53 and bounds therein a working chamber 5t which is in open communication with the bore 35 of the shaft 3. 'Thepiston 54 is provided with splines 5'! engaging slots 55 in the cylinder body 53. The said piston 54 has also a female quick pitch thread in engagement with a corre sponding male thread 55 provided on the driving shaft 9 which, in a way not shown in the draw ingsyis coupled to the crank-shaft of the internal combustion engine. The driving shaft 9 is supported in a ball-bearing 6 lodged in the housing 5. As already mentioned, the device shown in Fig. 3 is intended to replace the corresponding device in the apparatus shown in Fig. 1, so that the fuel injection pump Hit, the gear pump fitted thereto in the housing 9, and the means connecting the delivery chamber in the'latter to the bore 3! of the cam shaft 3, may be constructed exactlyas shown in Fig. 1 and have therefore ternal combustion engine, its quick-pitch screwthread 55 causes the piston 54 to revolve also, thus driving, by means of the splines El, the cylinder body 53 and the cam shaft 3, which actuates the injection pump and the gear pump not shown As described with reference to Fig. 1, a liquid pressure increasing with engine speed is set up in the bore 3|. Because of the opencommunication between the said bore and the working chamber 5!), this pressure is also effective in the latter. When the engine speed increases, the pressure overcomes the force of the spring 53 and displaces the piston M to the right. Ow ing tothe high-pitch thread 55, the said piston is also angularly displaced relatively to the shaft .9. The cylinder body 53 and the cam shaft 3 follow this angular displacement, thus advancing the time of injection relatively to the working cycle of the internal combustion engine.

In the embodiment shown in Figs. 4 and 5, the injection pump I06 is of similar design as shown in Fig. 1. Its cam shaft 3 is connected to the drive shaft 9 by means of an angularly adjustable coupling comprising a drive member 5 keyed to the shaft 9, a cover piece 8 rotatably mounted on shaft 3 and securedto themember I by screws 8a and provided with internal quick pitch thread 6|. The end portion of shaft 3 has parallel slots I4. The piston I I also is provided with a tubular extension I2 having onits outside a quick pitch thread I5 engaging thread 6! of the cover piece 8 and internal splines I 3 engaging the slots M of shaft 3, and it is axially displaceable in a cylindric recess I of the drive member I, in which it defines a working chamber 82., The parts and their features as thus fardescribed are similar to the corresponding onesin Fig. 1. However, the piston I I has a cylindric axial hole 63 tightly fitted by the tube 64, which latter is secured to the housing '65, at the other end of the injection .25 pump I08, and extends through the whole length of the axial passage 65 provided in the cam shaft 3. Adjacent to its ball bearing .2, the latter carries a bevel gear wheel 67 keyed thereto and secured by a nut 63. In the bottom portion of the isprovided between wheel 13 and the housing 65. The other spur wheel II is journalled on the pin 14, which alsois supported in the said housing E5 and cover 69. m

Both wheels I0 and II tightly fit a recess of the housing 65, but a supply chamber I5 and a delivery chamber I6 are provided adjacent to the place where their teeth are in engagement. Lubricant or fuel oil is supplied from some source to the supply chamber I5 through the conduit I1 and carried to the delivery chamber I6 when the gear wheels and Hare revolving in their normal sense of rotation indicated by the arrows. From the delivery chamber Hi, the oil is carried away through the duct 18 and the conduit I9. In the duct I8, a restricted passage 8b is provided, whose cross-section may be adjusted by the screw pin 8I.

The tube 64 has a portion 82 of greater diameter which fits a corresponding opening in the wall of housing 65, and an abutment 83 between which and the housing wall a packing 84 is interposed. On the other side of the said Wall, a nut 85 tightened on another packing 8t cooperates with the abutment 83 to hold the tube 64 in to Fig. 1, it will readily be seen that, owing to the throttling effect in the passage as, the oil sup? plied to the delivery chamber I6 by the cooperating gear wheels H3 and II is under a pressure increasing with the speed of rotation of said wheels, i. e., with the speed of the internal combustion engine. This pressure is transmitted to the working chamber 62; through the ducts I8 and 81, the groove 88, the hole 89, and through the tube 64. In the chamber 62, the said pressure becomes effective on piston II, displacing the latter to the left against the resistance of spring It, as engine speed increases. The said piston simultaneously effects an angular displacement due to the quick pitch threads I5 and 6| and thus advances the time of injection with reference to the angular position of shaft 9 and the working cycle of the internal combustion enue.

What I claim is:

1. The combination of a rotatable shaft having axial passage formed therein; a rotatable member axially aligned withsaid shaft; a cylinder and an axially shiftable piston enclosing together a variable working space; a spline connection between said piston and said rotatable member and a spline connection between said piston and said shaft, at least one of said spline connections being helicoidal and the spline connections so arranged that axial displacement of the piston entails relative angular displacement of said rotatable member and said shaft; a housing enclosing a fluid-containing space, means adapted for maintaining a controlled fluid-pressure in said fluid-containing space; means connecting said variable working space through said passage in said shaft to said fluid-containing space; and yielding means opposing axial displacement of said piston by the fluid pressure in said variable working space.

i 2. The combination of a rotatable shaft having an axial passage formed therein, a rotatable member axially aligned with said shaft and havspline connection between said piston and said rotatable member and a spline connection between said piston and said shaft, at least one of said spline connections being helicoidal and the spline connections so arranged that axial displacement of the piston entails relative angular displacement of said rotatable member and i said shaft; a housing enclosing a fluid-containing space; means adapted for maintaining a controlled fluid-pressure in said fluid-containing space; means connecting said variable working space through said passage in said shaft to said fluid-containing space; and yielding means opposing axial displacement of said pistonby the fluid pressure in said variable working space.

3. The combination of a rotatable shaft having an axial passage formed therein; a rotatable member axially aligned with said shaft; a cylinder carried by said shaft and an axially shift- I able piston, which cylinder and piston enclose together a variable working space; a spline connection between said piston and said rotatable member and a spline connection between said piston and said cylinder, at least one of said spline connections being helicoidal and the spline connections so arranged that axial displacement of the piston entails relative angular displacement of said rotatable member and said shaft; a housing enclosing a fluid-containing space; means adapted for maintaining a controlled fluid-pressure in said fluid-containing space; means connecting said variable working space through said passage in said shaft to said fluidcontaining space; and yielding means opposing axial displacement of said piston by the fluidpressure in said variable working chamber.

. i. The combination .of a rotatable shaft having an a ial passage formed therein; a rotatable member axially aligned with said shaft; a cylinder; a piston provided with an opening and axially shiftable in said cylinder, said cylinder piston enclosing together a variable working space; a spline connection between said piston and said rotatable member and a spline conmotion between said piston and said shaft, at least one of said spline connections being heliccida-l and the spline connections so arranged that axial displacement of the piston entails relative angular displacement of said rotatable member and said shaft; a housing enclosing a fluid-containing space; means adapted for maintaining a controlled fluid-pressure in said fluidecntaining space; means connecting said variable working space to said fluid-containing space, through said opening in said piston and through said passage in said shaft.

5. The combination of a rotatable shaft having an axial passage formed therein; a rotatable member axiallyaligned with said shaft; a cylinder and'an axially shiftable piston enclosing together a variable working space; said piston being splined to said rotatable member and to said shaft, in such a way that axial displacement of the piston entails relative angular displacement of said rotatable member and said shaft; a housing enclosing a fluid-containing space; means adapted for maintaining a controlled fluid-pressure in said fluid-containing space; tubular means guided on said shaft and on said housing so as to allow for motion of the shaft relatively to the housing whilst forming a fluid-tight connection between said fluid-containing space and said passage in the shaft; means forminga fluidtight connection between said passage in the shaft and said variable working space; and yielding means opposing axial displacement of said piston by the fluid pressure in said variable.

working space. I

6. The combination of a rotatable shaft having an formed therein; a rotatable member axially aligned with shaft; a cy nder; a piston pro ed with ano ening and axially shiftable in said cylinder, said cylin and piston enclosing together a variable working space, said piston. being spliced to said rotatable member to said shaft in such a way that axial displacement of the piston entails relative angular displacementef said rotatable member and said shaft; a housing enclosing a fluid-- containing space; means adapted for maintain-- ing a controlled fluid pressure in said fluidcontaining space; tubular means guided on said shaft and on said housing so as to allow for motion of shaft relatively to said housing whilst, a fluid-tight connection between said fluid-containing space and said passage in the shaft; tubular means guided on said shaft and in the opening of said piston. so as to f: m a fluid-tight connection between. said in the shaft and the said variable workingchain oer While allowing for relative motion of said shaft and piston; and yielding means opposing axial displacement of said piston by the fluid pressure in said variable worlii space.

7. The combination of a rot ble shaft having an axial passage formed therein; a rotatable member axially aligned with said shaft; a cylinder carried by shaft and an axially shiftable piston enclosing together a variable housing; a driven 'and axially aligned with said working space in open oemmunication with said passage in the shaft, said piston being splined to said rotatable member and to said shaft, in such a way that axial displacement of the piston entails relative angular displacement of said rotatable member on said shaft; a housing enclosing a flu l -containing space; means adapted for maintaining a controlled fluid pressure in said fluid-containing space; tubular means guided on said shaft and on said housing so as to allcwformotion of shaftrelatively to said housing whilst forming a iluid-tight connection between said fluid-containing space and said passage in the shaft; yielding means opposing axial displacement of said piston by the fluid pressure in said variable working space.

8. he combination of a rotatable shaft having an axial passage formed therein; a rotatable member axially aligned with said shaft; a cylinder; a pistonprovided with an opening and axially shiftable in said cylinder, said cylinder and piston-enclosing together variable working space; saidpiston being splined to said rotatable member and tosaid shaft in such a way that axial displacement of the piston entails relative angular. lacernent of said rotatable member and said shaft; a, housing enclosing a fluid-containing space; means adapted for main.-

a contrelled fluid pr sure in fluicontaining space; tubular mean. secured to s ment of said piston. by the fluid pressure in said variable working space.

9. The combination of a substantially closed housing; a driven shaft'mounted to rctate in said housing and having both ends enclosed thereby; a driving shaft entering said housing and axially aligned with said driven shaft; a cylinder turning with and forming an extension of one of said shafts within housing; a pie 1 axially shiftable in said cylinder, interposed between the ends of said shafts and having torque transmitting spline connections with each of said shafts, at least one of s i spline comiections being helicoidal; fluid transmitting connection for conducting pressure fluid to said cylinder to act against said piston, said connection leading axially through the drivenshaft from the end thereof remote from said piston; means'ior deliver 'ng fluid under controlled pressure to said connection; and yielding means resisting movement of said piston under such fluid pressure.

16. The combination cfa substantially closed shaft mounted to in having both ends enclosed shaft entering said housing I driven s aft; a cylinder turning with and forming an of one of said shafts Within said housing; a

rctate said housing and thereby; a driving piston axially shiftable in said cylinder, inter-' shaft fromthe end thereof remote from said id housing, extending through said passage in s id arranged to deliver fluid under controlled pressure to said axial connection for developing fluid pressure in said cylinder; and yielding means resisting movement of said piston under such fluid pressure.

11. The combination of a substantially closed housing; a driven shaft mounted to rotate in said housing and having both ends enclosed thereby; a driving shaft entering said housing and axially aligned With said driven shaft; a cylinder turning with and forming an extension of said driving shaft Within said housing; a 1oiston axially shiftable in said cylinder, interposed between the ends of said shafts and having torque transmitting spline connections with each of said shafts, at least one of said spline connections being helicoidal; a fluid transmitting connection for conducting pressure fluid to said cylinder to act against said piston, said connection lead ing axially through the driven shaft from the end thereof remote from said piston, and including a leak-resisting slip connection with the piston, leading through the piston and adapted to permit functional movements of the piston; means for delivering fluid under controlled pres sure to said connection; and yielding means resisting movement of said piston unde1qsuch fluid pressure.

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