US3709001A

US3709001A - Hydraulic-type fuel-injection automatic timer

Info

Publication number: US3709001A
Authority: US
Inventors: S Suzuki
Original assignee: Diesel Kiki Co Ltd
Current assignee: Bosch Corp
Priority date: 1970-07-06
Filing date: 1970-07-06
Publication date: 1973-01-09
Anticipated expiration: 1990-01-09

Abstract

A hydraulic, automatically adjustable timing device for regulating fuel injection. A pair of springs control outward movement of a flyweight responsive to driving shaft speed and hence permit different control characteristics at low and high speeds. The relative angular positions of the driving and driven shafts depend on the relative positions of a casing forming working chambers and a rotor having vanes located in the working chambers, the torque being transmitted through the casing, the rotor and the fluid in the working chambers. a valve member having valve elements with a solid periphery and inclined parallel faces is rotated with the outward movement of the flyweights to control the flow of pressurized fluid to the various portions of the working chamber.

Description

United States Patent [1 1 Suzuki 14 1 Jan. 9, 1973 [54] HYDRAULIC-TYPE FUEL-INJECTION AUTOMATIC TIMER [75] Inventor: Sholchi Suzuki, l-ligashi-Matsuyamashi, Japan [73] Assignee: Diesel Kiki Kabushiki Kaisha,

Tokyo, Japan [22] Filed: July 6, 1970 [21] Appl. No.: 52,248

[52] US. Cl. ..64/25, 73/537, 91/458, 137/56 [51] Int. Cl ..Fl6d 3/10 [58] Field of Search ..64/25; 91/458, 366; l37/625.22, 625.23, 625.24, 56; 73/537 [56] 8 References Cited UNITED STATES PATENTS 314,353 3/1885 Thompson ..73/537 2,786,667 3/1957 Gaubatz ..73/537 X 3,146,795 9/1964 Retallick ..137/625.23 X 752,472 2/1904 Schilde ..91/464 X 2,107,070 2/1938 Fleury ..64/25 2,708,353 5/1955 Brady ..64/25 2,708,354 5/1955 Brady et a1. ...64/25 2,743,593 5/1956 Bischoff ..64/25 3,003,341 10/1961 Aland ..64/25 FOREIGN PATENTS OR APPLICATIONS 561,811 6/1944 Great Britain ..64/25 Primary Examiner-Martin P. Schwadron Assistant Examinerlrwin C. Cohen Attorney-Larson, Taylor and Hinds [57] ABSTRACT A hydraulic, automatically adjustable timing device for regulating fuel injection. A pair of springs control outward movement of a flyweight responsive to driving shaft speed and hence permit different control characteristics at low and high speeds. The relative angular positions of the driving and driven shafts depend on the relative positions of a casing forming working chambers and a rotor having vanes located in the working chambers, the torque being transmitted through the casing, the rotor and the fluid in the working chambers. a valve member having valve elements with a solid periphery and inclined parallel faces is rotated with the outward movement of the flyweights to control the flow of pressurized fluid to the various portions of the working chamber.

Z Clairns, 5 Drawing Figures n 34 30 C B 13 3| 4 5 [is (0 PAIENTEUJAM 9|975 I 3 709 001 sum 1 OF 3 FIG.I

PATENIEDJAN 9197s I 3 7090M SHEET 2 [1F 3 HYDRAULIC-TYPE FUEL-INJECTION AUTOMATIC TIMER The invention relates to a hydraulic-type fuel-injection automatic timing device for fuel-injection pumps.

The advantages of conventional automatic timers of this kind are:

l. accurate timing action,

2. large driving torque-transmitting capacity, and a stable angle of advance even under condition of large fluctuation in the torque absorption within the injection pump, which properties are of particularly high merit when the timer is used on a large-size internal combustion engine, and

3. no need of preparing any special fluid for use within the timer, engine oil or fuel oil being used in the timer.

It is an object of the invention to provide a hydraulictype fuel-injection automatic timing device possessing, to these advantages, the following desirable properties:

1. a wider range of adjustable timing is possible (a large angle of advance is obtained);

2. advance characteristic in low-speed region can be made to differ from that in high-speed region;

3. angle of advance can be linearly related to revolving speed of engine, and

4. a timer, possessing all these advantages, is relatively simple in construction and can be made copact, so that the cost of manufacture is low.

A timer in general of the kind is composed of vanes provided on a rotor which is secured to a drive shaft at a connected side with an engine crankshaft and a casing secured to a driven shaft at a connected side with an injection-pump camshaft, and enclosing said rotor vanes to form operating chambers. These chambers are oil-tight and filled with hydraulic fluid, so that drive torque is transmitted from the drive shaft to the driven shaft through the rotor, hydraulic fluid and casing. Inlet and outlet passages of fluid under pressure for said operating chambers are controlled by sleeve valves positioned concentric with the rotor. The sleeve valves are turned by the centrifugal force exerted by flyweights, which are mounted on the drive shaft. A change in revolving speed of the engine causes the sleeve valves to turn in one direction or the other to admit hydraulic fluid under pressure into one operating chamber while relieving the fluid from another chamber, thereby introducing a pressure differential between each pair of adjacent operating chambers to twist the rotor relative to the casing, that is, to increase or decrease the angle of advance.

This invention purports to provide new and novel features in regard to a mechanism for controlling hydraulic fluid in operating chambers in such construction.

In order that this invention may be more readily understood, reference will now be made, by way of example, to the accompanying drawings in which:

FIG. 1 is a longitudinal cross section of a device according to the invention, taken along line A-A of FIG.

FIG. 2 is a transverse cross section taken along line B-B of FIG. 1,

FIGS. 3 and 4 are transverse cross sections taken along lines C-C and D-D of FIG. ll respectively, and

FIG. 5 is the end view ofFIG. ll.

A drive shaft 1 is connected with the engine crankshaft, not shown, by means of its splines 2. A rotor 3 with

vanes

3a, 3b is splined onto the drive shaft 1 by means of splines d. The

vanes

3a, 3b are each fitted with a seal S at the peripheralface of the vane. These faces with sea] S are in oil-tight sliding contact with the wall of casing 5. The ends of casing 5 are closed with end plates 6 and 7, which are in oil-tight sliding contact with the drive shaft 1 and end faces of the rotor and the vanes. To the outer sides of end plates 6 and 7,

covers

8 and 9 are fitted, one cover to one plate, presenting oil-tight sliding contact with the peripheral surface of drive shaft 1, there being formed an enclosed space between the end plate and the cover at each end. The two spaces so formed are designated as oil-tight chambers 10 and 11. The casing 5, the end plates 6 and 7 and the

covers

8 and 9 are rigidly secured together by bolts 12 to pump-side gear 13 located at the end opposite to the other end where splines 2 are located. The gear 13 is engaged with the injection-pump camshaft, not shown, through splines 13a. In the chamber 14 formed between the cover 9 and the gear 13, a pair of flyweights 15 are disposed symmetrically with respect to the axis of drive shaft 1, with one end of each flyweight 15 being rotatably pivoted on stud l7 screwed into plate 16, so that each flyweight is capable of rocking motion, and with the other end of flyweight 15 being urged by spring 19 toward screw 18 threaded into the cover 9 to secure a plate 16 to this cover, so that the centrifugally expanding movement of flyweights 15 is opposed by springs 19 whose ends are hooked onto the free ends of flyweights l5 and onto the protruding heads of screws 18. The plate 16 can be angularly repositioned to adjust the preload of springs 19 by loosening said screws 18 and twisting it in place.

By its rocking motion, each flyweight l5 exerts twisting force through slot 20 formed in the inner end portion of the flyweight to pin 21 engaged with this slot. Pins 21, extending into chamber 14, are studded in plate 22c rigidly mounted on the end of rotary shaft, or valve rod 22, which carries pilot valve, or valve element, 22a at its one end and another pilot valve, or valve element 22b at its other end.

Pilot valves

22a and 22b are cylindrical in shape; their parallel end faces are inclined relative to the axis'of shaft 22; and their peripheral surfaces are in oil-tight contact with the bores of bushes la and 1b fitted into the center bore of drive shaft 1. Thus, it is these bushes that support rotary shaft 22 in place. Centrifugal force causesthe flyweights to expand against the force of springs l9. When flyweights so move, this movement is transmitted by pins 21 and plate 220 to shaft 22 to rotate

pilot valves

22a and 22b in clockwise direction as referred to FIG. 2. Two adjusting bolts, each holding secondary spring 23a in the bore provided in the bolt, are threadedly secured to cover 9 and sopositioned as to elastically meet the expanding flyweights by the free ends of their springs 23a, thereby opposing to the expanding motion of the flyweights. This opposing action adds to that of springs 19 in the high-speed region, that is, when the revolving speed of the engine is abovea predetermined speed level, and thus alters the advance characteristic of the timer for that region of the speed range. The level of rising speed at which secondary springs 23a begin to act can be selected by repositioning adjusting bolts 23 equally. This can be accomplished by loosening nuts 24 and by equally running bolts 23 in orout. Torsion-compression spring 25, interposed between and anchored to bush lb and plate 220, is so oriented and preloaded as to urge flyweights 15 outwardly in opposition to the tensile force of springs 19 and to push on plate 220 axially. By the torsional and compressive preload of spring 25, the play, if any, between flyweight and pin 21 is eliminated and

pilot valves

22a and 22b are retained in their respective positions along the axis of drive shaft 1.

At the drive side, collar 26 is mounted on drive shaft 1 and against the outer end face of cover 8 with an oiltight fit. Inlet oilway 27, a hole drilled radially in collar 26 is. communicated to chamber 30 formed in the center bore of drive shaft 1 between

pilot valves

22a and 22b. This communication is through oilway 28 extending radially into drive shaft 1 and oilway 29 cut in the peripheral surface of bush la and extending along the bush-holding bore of shaft 1. Oilway 29 opens out into chamber 30at the inner end of bush 1a. Chamber 10 is communicated to the bore of bush la through a passage formed by

oilways

31 and 32 extending radially into shaft 1 and bush Ia. Chamber 11 is similarly communicated to the bore of bush lb through a passage formed by

oilways

33 and 34 extending radially into shaft 1 and bush lb. The openings of

oilways

32 and 34 are so located as to be covered by

pilot valves

22a and 22b, whose axial thickness is made equal to or slightly larger than the size of respective opening. As rotary shaft 22 turns in clockwise direction as referred to FIG. 2 when the pilot valves are in the positions for fully covering the openings, valve 22a opens oilway 32 to the atmospheric side opposite to chamber 30 and valve 22b opens oilway 34 to chamber 30. Conversely, if shaft 22 turns in counterclockwise direction, oilway 32 opens to chamber 30 and oilway 34 opens to the atmospheric,

side. Thus, the openings ofoilways 32 and 34 are controlled by the rotary movement of pilot valves 22a and Inside casing 5, radial protrusions a, 5b extending axially, are formed on the inside wall of casing 5. Corresponding to these radial protrusions, bosses are formed'on the hub portion of rotor 3, each boss being fitted with

seal S. Protrusions

5a, 5b are in sliding contact with the lands of said bosses, the contact being made oil-tight by the seal, thereby introducing identical chambers equalingin number to

vanes

30, 3b Each chamber is divided by a vane into two operating chambers, or portions, say, by vane 3ainto operating chambers, or first and second portions, 35a and 35b, representing other similar operating chambers. Chamber 35a is communicated through oil hole 6a, a drilled hole in' end plate 6, to chamber between end plate 6 and cover 8. Similarly, chamber 35b is communicated through oil hole 7a, a drilled hole in end plate 7, to chamber 11 between end plate 7 and cover 9. Of

. the vanes of rotor 3, vane 3a in particular is provided with two stopper 3:, one on each side face of this vane, to meet the side faces of radial protrusions 35a and 35b. The purpose of these stoppers 3s is to limit the range of relativeangular displacement between rotor 3 and easing 5, so that the end faces of

vanes

30, 3b will not cover up oil holes 6a and 70 provided in the two end plates for respective operating chambers 35a, 35b It should be noted here that the timer of the invention shown in the drawings is to operate with its drive shaft 1 rotating counterclockwise as referred to FIG. 2.

The operation of the timer so constructed will now be explained. Suppose the revolving speed of the engine increases to cause flyweights 15 to expand by an amount corresponding to the rise in speed against the force of springs 19: then rotary shaft 22 and hence pilot valves 22a and 2212 will turn clockwise, as seen in FIG. 2, relative to drive shaft 1, thereby opening

oilways

32 and 34. These oilways, now open, respectively communicate operating chamber 35a to the atmospheric side through oil hole 6a, chamber 10 and oilways 31 and 32, and operating chamber 35b to chamber 30 through oil hole 7a, chamber 11 and oilways 33 and 34. Communications take place similarly to the other operating chambers, which are represented, for the purpose of illustration, by chambers 35a and 35b. Since chamber 30 is always supplied with high-pressure hydraulic oil from a supply pump, not shown, through

inlet oilways

27, 28 and 29, the high-pressure oil flows from chamber 30 into operating chamber 351;, while the oil pressure, if any, in operating chamber 35a becomes bled out to the atmospheric side. Consequently, a pressure differential occurs between chambers 35a and 35b to turn casing 5 relative to, and in the same direction as that of, drive shaft]. This turning advances gear 13 angularly relative to drive shaft 1. In other words, the turning of casing 5 changes the phase relationship between shaft 1 and gear 13 and, in the present instance, increases the angle of advance. As casing 5 so turns, plate 16,.held integrally to this casing, and flyweights l5 mountedfon this plate turn together, and pins 21 transmits this rotary movement to shaft 22, thereby turning

pilot valves

22a and 22b counterclockwise, as viewed in FIG. 2, to close oilways 32 and 34 again. By this closure, the oil in operating .chambers 35a and 35b becomes trapped to keepthe pressure differential and thus maintain the increased angle of advance.

Above a predetermined speed level, that is, in the high region of the speed range, the expanding movement of flyweights 15 becomes countered by secondary springs 23a, so that the speed characteristic of advance is different from that in the low region of the speed range. Stated specifically, the action of springs 23a in addition to that of springs 19 makes the timer provide less advance for a given increment of speed. Obviously, by using proper springs 19 and 23a in proper combination, a desired characteristic can be obtained in the timer according to the invention.

For a fall in speed on the other hand, flyweights l5 contract under the force of springs 19, and this contracting movement, which is opposite in direction to the expanding movement considered above, turns

pilot valves

22a and 22b counterclockwise, as referred to FIG. 2, thereby communicating operating chamber35a to chamber 30 and operating chamber 35b to the atomospheric side. As results of these communications, the high-pressure oil flows into chamber 35a while the pressure, if any, in chamber 35b becomes bled out, so that casing 5 turns in the opposite direction by an amount corresponding to said fall in speed. Thereupon, said pilot valves trap the oil in respective operating chambers by reversing the sequence of events mentioned above, to make the timer maintain the altered phase relationship and continue to transmit drive.

Since hydraulic oil is incompressible, the timer is capable of accurately transmitting drive torque regardless of its magnitude, without allowing the angle of advance to be changed even when large changes in drive torque occur during operation. Moreover, the relationship between the speed and the angle of advance can be made linear by properly positioning springs 19 and 23a relative to a line normal to the line drawn through the center point of stud 17, on which flyweight is pivoted, and the point at which the spring acts on the flyweight, so that a proper angle will be included between each spring and said normal line. Without this included angle for each spring, the relationship between the speed and the angle of advance would describe a secondary characteristic curve simply because spring force is proportional to centrifugal force, which varies as the square of speed; but, with the angle properly included between each spring and said normal line, the progressive expansion of flyweights 15 will make the included angle progressively smaller to increase the force of spring correspondingly, so that this increasing spring force will begin to vary, as governed by said secondary characteristic curve, with centrifugal force to cancel off the effect of the relationship between centrifugal force and speed and thus result in said linear relationship.

it will be noted in the foregoing description that the timer according to the invention is capable of being built small and compact on account of these distinctive features: Oilways for providing the flow of hydraulic oil into and out of operating chambers 35a and 35b open out at the bore within drive shaft 1, so that

pilot valves

22a and 22b are cylindrical in shape and small in diameter because they are located within said bore; the axial thickness of said pilot valves is minimized to minimize their sliding surfaces because the end faces of said pilot valves are slanted relative to the axis of shaft 22 in order that turning these valves will open and close said oilways depending on the direction of turning; flyweights 15 for turning the pilot valves can be made small because they need not have a large mass otherwise necessary to overcome large friction. More importantly, the adjustable range in terms of revolving speed can be made wider and, in addition to the above merit of practical value, the timer according to the invention permits a plurality of springs to be employed to control the flyweights, thereby making available diverse advance characteristics for a wide variety of requirements imposed by engines.

Many variations may be effected without departing from the spirit of the invention. It is to be understood that these, together with other variations in details, are anticipated by the appended claims.

What is claimed is:

l. A device for regulating the angular relationship between a driving shaft and a driven shaft axially aligned with the driving shaft and angularly adjustable with respect to the driving shaft,

a casing fixed to rotate with one of said shafts, said casing surrounding the rotor and defining working chambers opened radially inwardly,

a rotor fixed on the other of said shafts to rotate therewith, said rotor having a hub covering the inner openings of the working chambers and vanes extending radially outwardly from the hub into the working chambers to define with each working chamber first and second fluid sealed portions, wherein when the working chambers are filled with hydraulic fluid, torque can be transmitted from the driving shaft through the hydraulic fluid to the driven shaft,

the rotor being movable angularly with respectto the casing such that enlarging either of the first or second portions while concurrently reducing the other of said first or second portions varies the angular relationship between the rotor and the casing and hence between the driving and driven shafts,

fluid control means for controlling the flow of hydraulic fluid to said working chambers, said control means having a first position in which pressurized hydraulic fluid is introduced into the said first portions and drained from the said second portions of the working chambersya second position in which pressurized hydraulic fluid is introduced into the second portions and drained from the said first portions, and a third position in which hydraulic fluid is concurrently held in said first and second portions,

said control means comprising an axially extending cylindrical passage located within the device axially aligned with said shafts, first fluid lines leading from said passage to the first portions, second fluid lines leading from said passage to the second portions, means for delivering hydraulic fluid to this passage and means for draining hydraulic fluid from this passage,

a axially fixed valve member located in the passage comprising a rod and a pair of valve elements fixed on the rod, one valve element covering each of said first and second fluid lines, each valve element being cylindrical and having a solid outer periphery of an axial dimension sufficiently large to cover its respective fluid line, said valve element having radial faces parallel with each other and parallel with the faces of the other valve element, said parallel faces being oblique to the said axis, wherein in the said first position of the control means the valve member is rotated to a first position to permit hydraulic fluid into the first fluid lines and to drain fluids from the second fluid lines,

in the said second position of the control means the valve member is rotated to a second position to permit hydraulic fluid into the second fluid lines and to drain fluid from the first fluid lines, and in said third position of the control means the valve member is rotated to close both of said first and second fluid lines,

a pair of flyweights, each pivotally connected to both the valve member and the casing to be movable outwardly by centrifugal force, a spring means for urging the flyweights radially inwardly in opposition to said centrifugal force, said spring means including a first spring urging the flyweights radially inwardly, and a second spring to assist the first spring only after the flyweights have moved outwardly a predetermined amount, the second spring thus limiting the capability of the flyweights to vary the position of the valve member for increasing speeds beyond a predetermined speed, the said connection of the flyweights and the valve member including means for rotating the valve member between said first, second and third positions in response to the radial position of the flyweights, and the said connection of the flyweights to the between the flyweightsand the valve member compris- 10 ing a plate fixedvto the valve rod and having pins thereon, said flyweights having slots associated with the pins such that upon outward movement of the flyweights the slots engage the pins to turn the plate and hence turn the valve member.

casing including means for rotating the valve member in response to relative movement between the casing and the rotor,

whereby the valve member is normally in said third position closing the first and second fluid lines, and

a change in speed moves the valve member to one of said first or second positions to permit hydraulic

Claims

1. A device for regulating the angular relationship between a driving shaft and a driven shaft axially aligned with the driving shaft and angularly adjustable with respect to the driving shaft, a casing fixed to rotate with one of said shafts, said casing surrounding the rotor and defining working chambers opened radially inwardly, a rotor fixed on the other of said shafts to rotate therewith, said rotor having a hub covering the inner openings of the working chambers and vanes extending radially outwardly from the hub into the working chambers to define with each working chamber first and second fluid sealed portions, wherein when the working chambers are filled with hydraulic fluid, torque can be transmitted from the driving shaft through the hydraulic fluid to the driven shaft, the rotor being movable angularly with respect to the casing such that enlarging either of the first or second portions while concurrently reducing the other of said first or second portions varies the angular relationship between the rotor and the casing and hence between the driving and driven shafts, fluid control means for controlling the flow of hydraulic fluid to said working chambers, said control means having a first position in which pressurized hydraulic fluid is introduced into the said first portions and drained from the said second portions of the working chambers, a second position in which pressurized hydraulic flUid is introduced into the second portions and drained from the said first portions, and a third position in which hydraulic fluid is concurrently held in said first and second portions, said control means comprising an axially extending cylindrical passage located within the device axially aligned with said shafts, first fluid lines leading from said passage to the first portions, second fluid lines leading from said passage to the second portions, means for delivering hydraulic fluid to this passage and means for draining hydraulic fluid from this passage, a axially fixed valve member located in the passage comprising a rod and a pair of valve elements fixed on the rod, one valve element covering each of said first and second fluid lines, each valve element being cylindrical and having a solid outer periphery of an axial dimension sufficiently large to cover its respective fluid line, said valve element having radial faces parallel with each other and parallel with the faces of the other valve element, said parallel faces being oblique to the said axis, wherein in the said first position of the control means the valve member is rotated to a first position to permit hydraulic fluid into the first fluid lines and to drain fluids from the second fluid lines, in the said second position of the control means the valve member is rotated to a second position to permit hydraulic fluid into the second fluid lines and to drain fluid from the first fluid lines, and in said third position of the control means the valve member is rotated to close both of said first and second fluid lines, a pair of flyweights, each pivotally connected to both the valve member and the casing to be movable outwardly by centrifugal force, a spring means for urging the flyweights radially inwardly in opposition to said centrifugal force, said spring means including a first spring urging the flyweights radially inwardly, and a second spring to assist the first spring only after the flyweights have moved outwardly a predetermined amount, the second spring thus limiting the capability of the flyweights to vary the position of the valve member for increasing speeds beyond a predetermined speed, the said connection of the flyweights and the valve member including means for rotating the valve member between said first, second and third positions in response to the radial position of the flyweights, and the said connection of the flyweights to the casing including means for rotating the valve member in response to relative movement between the casing and the rotor, whereby the valve member is normally in said third position closing the first and second fluid lines, and a change in speed moves the valve member to one of said first or second positions to permit hydraulic fluid to change the relative angular position of the rotor and the casing, and wherein movement of the casing to a new angular position acts through the connection of the casing to the flyweights and the connection of the flyweights with the valve member to move the valve member to said third position.

2. A device according to claim 1, said connection between the flyweights and the valve member comprising a plate fixed to the valve rod and having pins thereon, said flyweights having slots associated with the pins such that upon outward movement of the flyweights the slots engage the pins to turn the plate and hence turn the valve member.