US3791171A

US3791171A - Centrifugal governor particularly for altering the moment of injection start in diesel engines

Info

Publication number: US3791171A
Application number: US00269174A
Authority: US
Inventors: E Hofmann
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1971-07-14
Filing date: 1972-07-05
Publication date: 1974-02-12
Anticipated expiration: 1991-02-12
Also published as: IT965708B; CH536937A; AT311725B; DE2135111A1; GB1398930A; BR7204605D0; ES404880A1; NL7209166A; DE2135111B2; FR2146040A5; BE786249A

Abstract

In a centrifugal governor connecting a driving shaft with an axially aligned driven shaft for varying the phase angle between the two shafts in an rpm-dependent manner, each centrifugal weight rotates in unison with the driving shaft and has a rigidly affixed pin extending parallel to and spaced from the pivotal axis of the weight. The pin projects beyond either side of the weight. One terminus of the pin is in continuous engagement with a curved track of a component keyed to the driven shaft for changing the phase angle as the weights swing in response to an rpm change. The other terminus of the pin carries an abutment ring of arbitrary diameter which, after the weight has swung through a predetermined path, engages the bounding edge of a recess provided in a component affixed to the driving shaft to limit the phase angle alteration to a predetermined, arbitrary value.

Description

United States Patent [191 Hofmann [451 Feb. 12, 1974 [75] Inventor: Eberhard Hofmanm'Kirchberg/M.

. Neuhof, Germany [73] Assignee: Robert Boach GmbH, Stuttgart,

Germany I [22] Filed: July 5, 1972 [21] Appl. NO.: 269,174

[30] Foreign Application Priority Data 3,424,875 1/1969 Ojala 64/25 Primary Examiner- -Benjamin W. Wyche Assistant Examiner-Randall Heald Attorney, Agent, or Firm-Edwin E. Greigg [5 7] ABSTRACT In a centrifugal governor connecting a driving shaft with an axially aligned driven shaft for varying the phase angle between the two shafts' in an rpmdependent manner, each centrifugal weight rotates in unison with the driving shaft and has a rigidly affixed pin extending parallel to and spaced from the pivotal axis Of the weight. The pin projects beyond either side of the weight. One terminus of the pin is in continuous engagement with a curved track of a component keyed to the driven shaft for changing the phase angle as the weights swing in response to an rpm change. The other terminus of the pin carries an abutment ring of arbitrary diameter which, after the weight has swung through a predetermined path, engages the bounding edge of a recess provided in a component affixed to the driving shaft to limit the phase angle alteration to'a predetermined, arbitrary value.

3 Claims, 2 Drawing .ATENTEUFEB 12 I974 SHEET 10? 2 I 1 CENTRIFUGAL GOVERNOR PARTICULARLY FOR ALTERING THE MOMENT OF INJECTION START IN DIESEL ENGINES BACKGROUND OF TI-IE'INVENTION This invention relates to a centrifugal governor, particularly for altering the starting moment of injection in diesel engines and is of the type that has at least one centrifugal weight which is swung by rpm-dependent centrifugal forces against the force of at least one spring and which, as a function of the extent of its swinging displacement, varies the .phase angle A between axially aligned driving and driven shafts. The centrifugal governor is further of the type that includes a mechanism which sets an arbitrary'limit to the phase angle. The said mechanism is provided with at least one recess, the shape of which limits the displacement of a pin which is an integral part of the centrifugal weight and which projects therebeyond remote from the center of gravity thereof.

In centrifugal governors of the aforenoted type it is required to limit the phase shift between the axially "aligned driving'and driven shafts to various predetermined phase angles in case, for example, the governors are used in serial engines which are set without other substantial changes to various full load output values by limiting the full load rpm s. To these rpm s there are assigned corresponding phase angles. The most important reason'for providing a limitation to the phase angle, however, is to ensure that when the full-load rpm is reached, the motion of the A -altering mechanism is stopped and A is maintained at that value. If such limitation is absent then the centrifugal governor tends to oscillate in case of torque or rpm fluctuations. Such an oscillation of the governor components generates loud operational noises. Also, the engine runs unevenly and there is experienced a premature wear and breakdown of the governor.

In known centrifugal governors of the aforenoted type (such as disclosed, for example, in US. Pat. No. 1,967,445 and German Pat. No. 682,352) which serve for altering the moment of ignition in engines having battery operated ignition systems, the mechanism pro- 2. quirements of inexpensive mass production and renders possible simple and reliable readaptations.

Briefly stated, according to the invention, the rpmdependent course of the phase angle alteration is controlled in a known manner by means of a guiding track affixed to one of the shafts and further, the recess associated with the arbitrary limitation of the phase angle is arranged separately and spaced from the guiding track in a disc-shaped component affixed to the other shaft. The pin projecting from the centrifugal weight and extending into said recess is provided with an abutment ring which is adapted to engage an inner edge of the recess that is remote from the rotational axis of the vide d with the aforenoted recesses for limiting the phase angle has, at the same time, the function of controlling the rpm-dependent course of the A-change between the driving and the driven shaft. For this reason, the mechanism is fixedly attached tothe driven shaft and transmits the full driving torque. Each recess has to be machined very accurately in order to function properly as a curved guiding track. Such an arrangement is particularly disadvantageous if a governor of this type is, for changing the starting moment of injection, incorporated into the fuel injection pump for diesel engines because in such a case the requirements with regard to the accuracy of the curved guiding track and the stability of the governor components are particularly stringent.

OBJECT, SUMMARY AND ADVANTAGES OF THE INVENTION It is an object of the invention to provide an improved centrifugal governor which fulfills the aforenoted requirements, isfree from the disadvantages of known centrifugal governors, complies with the recentrifugal governor. The outer diameter of the ring carried by the pin is dimensioned in accordance with the desired phase angle limit A,.

By virtue of separating the guiding track from the phase angle limiting mechanism, no torque is transmitted through the latter.- Further, as far as the recesses are concerned, only their distance from the rotational axis of the centrifugal governor has to be accurately set.

The invention will be better understood as well as further objects and advantages become more apparent from the ensuing detailed specification of a preferred, although exemplary embodiment taken in conjunction with the drawing.

BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENT An only symbolically illustrated fuel injection pump 11 has a cam shaft 10 (driven shaft) on which there is inserted a centrifugal governor, generally indicated at 12. The-centrifugal governor has a hub 13 which serves as the driving shaft for the driven shaft 10 and which is'supported on a terminal shaft portion 14 of the cam shaft 10. The hub 13 is provided with pivots 15 on which there are swingably arranged centrifugal weights 18. I

On an axially forwardly projecting central extension 20 of the driving hub 13 there is supported a clutch member 22 which is provided with jaws 21 and which is connected at its radial face by means of bolts 23 to the driving hub 13. By means of a second clutch mem her (not shown) which surrounds the jaws 21 of the clutch member 22, the centrifugal governor is connected with the driving components of the engine, also not shown. It is to' be understood that instead of the particular clutch member 22 a gear wheel may be used as part of a gearing to serve as the coupling means between the engine and the centrifugal governor 12.

Each centrifugal weight 18 has, at a distance from its pivot 15, a pin 25 which extends parallel to and spaced from the governor axis and which projects beyondeither side of the weight 18. One end portion 25a of the pin 25 carries a roller 26 which, in turn, is in engagement with a curved track 27. The latter, which serves as a guiding curve, is provided on a lever-shaped transmission member 28 which, in turn, is integral with the cam shaft 10. The roller 26 is secured to the end portion 25a of the pin 25 against axial displacement by means of a retainer ring 29. The other terminal portion 25b of the pin 25 carries an abutment ring 30. When the centrifugal weight 18 executes its pivotal motion, the terminal portion 25b of the pin 25 moves within and across the recess 31 of a disc-shaped part 32 integral with the driving hub 13. Each recess 31 is, for manufacturing reasons, expediently of circular configuration as illustrated in FIG. 2; it may, however, have any other shape. The essential characteristic of the recess 31 is that the full swinging movement of the pin portion 25b carrying the abutment ring 30 must not be obstructed. The recess 31 is bounded by an inner edge 33 which the abutment ring 30 is adapted to contact when the weight 18 assumes an outer position. The radial distance A of the governor axis from that location of the inner edge 33 of the recess 31 which is in engagement with the abutment ring 30 when the centrifugal weight 18 is in its outer position, limits the swinging path of the centrifugal weights 18. In this manner the possible change of the phase angle between the driving shaft (that is, the hub 13) and the driven shaft (that is, the cam shaft 10) is also limited.

From the cooperation between the pin 25 and the recess edge 33 it is apparent'that the magnitude of the possible pivotal paths of the centrifugal weight 18 is a function of the outer diameter D of the abutment ring 30. Stated differently, by providing replaceable abutment rings 30 of an arbitrarily selected outer diameter D, the phase angle may be arbitrarily limited to a changeable value A,.

In the aforenoted manner a readaptation of the centrifugal governor may be effected in a very simple manner. The abutment rings 30 may be manufactured, for example, by precision stamping.

For the lubrication of the bearing of the flange 13 and the other governor components, the centrifugal governor is provided with oil bores 41, 41a, 41b and is surrounded, for'preventing any loss of oil, by means of a housing 42 which is affixed rigidly to the fuel injection pump 1 l. The housing'42 is provided with a sealing ring 43 which isolates the rotary centrifugal governor from the external environment in a fluid-tight manner. The centrifugal forces of the weights l8 generated during the operation of the governor are opposed by compression spring pairs 45 which at one end engage pivotable spring supports 46 and at the other end engage support pins 47 integral with lever 28. It is thus seen 'that the springs 45 urge the associated centrifugal weight 18 inwardly towards its position of rest through the lever 28, the roller 26 and the pin 25. As the rpm increases, the centrifugal weights 18 move against the force of the springs 45 outwardly in the direction of the arrow 50 and turn the

components

28, 10 of the driven side with respect to the components 13, 22 of the driving side until the abutment rings 30 arrive into engagement with the inner edge 33 of the recesses 31.

Dependent upon the diameter D of the abutment rings 31, there may be obtained a phase angle adjustment of, for example, A, 3, 4, 6 or 7 of the cam shaft of the fuel injection pump. The maximum phase angle A of, for example, 8 is achieved when the centrifugal weights 18 are permitted to execute their greatest possible pivotal motion. This is achieved,

for example, when no abutment rings 30 are present. In

such a case the pins 25 and their end portion 25b directly contact the inner edge 33 of the recesses 31. The cooperation between the

components

25b and 33 also prevents the orbiting weights 18 from contacting the stationary housing 42.

By means of the aforedescribed setting of the phase angle A between the driving shaft and the driven shaft there is achieved, with increasing rpms, a shift of the moment of injection start within the load range towards an earlier moment, while the abutment rings 30, as a function of their outer diameter, limit the phase angle to an arbitrary value A,..

What is claimed is:

1. A centrifugal governor for varying the phase angle in an rpm-dependent manner between a driving shaft and a driven shaft axially aligned .therewith, comprising A. at least one centrifugal weight,

B. means securing said centrifugal weight to a first one of said shafts forrotation as a unit therewith, said means permitting a movement of said centrifugal weight away from the rotary axis of the governor in response to an increase in the rpm of said last-named shaft,

C. means defining a curved track affixed to the second one of said shafts, 1

D. means for connecting said centrifugal weight with said curved track for controlling the rpmdependent shift of the phase angle as a function of the configuration of said curved track,

E. means defining a recess, said last-named means being affixed to the first one of said shafts, said recess being bounded by an edge and being spaced and separate from said curved track, said edge being remote from said rotary axis, I

' F. a pin affixed to said centrifugal weight, with one end portion thereof extending into said recess, and the other end portion thereof comprising said means for connecting said centrifugal weight with said curved track, said pin moving across said recess towards said edge upon movement of said centrifugal weight in response to an rpm change, and

G. an abutment ring of predetermined outer diameter secured to said end portion of said pin, said abutment ring arriving into contact with said edge during the course of outward motion of said centrifugal weight in response to an rpm increase, the cooperation between said edge and said abutment ring limiting the change of phase angle to a predeterminedvalue as a function of said outer diameter.

2. A centrifugal governor as defined in claim 1,

wherein said means defining said curved track is formed of a lever rigidly affixed to the second one of said shafts.

3. A centrifugal governor as defined in claim 2, including spring means for continuously urging said lever into contact with said other end portion of said pin to exert a force on said centrifugal weight, said last-named force opposing the centrifugal force imparted on said weight.

Claims

1. A centrifugal governor for varying the phase angle in an rpmdependent manner between a driving shaft and a driven shaft axially aligned therewith, comprising A. at least one centrifugal weight, B. means securing said centrifugal weight to a first one of said shafts for rotation as a unit therewith, said means permitting a movement of said centrifugal weight away from the rotary axis of the governor in response to an increase in the rpm of said last-named shaft, C. means defining a curved track affixed to the second one of said shafts, D. means for connecting said centrifugal weight with said curved track for controlling the rpm-dependent shift of the phase angle as a function of the configuration of said curved track, E. means defining a recess, said last-named means being affixed to the first one of said shafts, said recess being bounded by an edge and being spaced and separate from said curved track, said edge being remote from said rotary axis, F. a pin affixed to said centrifugal weight, with one end portion thereof extending into said recess, and the other end portion thereof comprising said means for connecting said centrifugal weight with said curved track, said pin moving across said recess towards said edge upon movement of said centrifugal weight in response to an rpm change, and G. an abutment ring of predetermined outer diameter secured to said end portion of said pin, said abutment ring arriving into contact with said edge during the course of outward motion of said centrifugal weight in response to an rpm increase, the cooperation between said edge and said abutment ring limiting the change of phase angle to a predetermined value as a function of said outer diameter.

2. A centrifugal governor as defined in claim 1, wherein said means defining said curved track is formed of a lever rigidly affixed to the second one of said shafts.