Claims:We claim:
1. A governor shaft 12 for a governor 10 of a high pressure fuel pump 1, said governor shaft 12 comprising:
a body 14;
a first radial bore 16 defined in said body 14;
an axial bore 18 defined in said body 14 and in flow communication with said first radial bore 16, said axial bore 18 adapted to channel fuel that is supplied from said first radial bore 16 through said governor shaft 12;
a second radial bore 20 defined in said body 14 and in flow communication with said axial bore 18, said second radial bore 20 adapted to channel fuel that is delivered from said axial bore 18 out of said governor shaft 12;
characterized in that
a plug 22 positioned within said axial bore 18;
a spring member 24 inserted within said axial bore 18, a first end of said spring member 24 in contact with said plug 22; and
a ball 26 inserted within said axial bore 18, said ball 26 positioned against said spring member 24 such that said ball 26 closes said second radial bore 20 to prevent fuel flow through said governor shaft 12 until a pressure of fuel entering said governor shaft 12 is above a threshold fuel pressure.

2. The governor shaft 12 as claimed in claim 1, wherein said axial bore 18 comprises a first portion 30 that is in flow communication with said first radial bore 16.

3. The governor shaft 12 as claimed in claim 2, wherein said axial bore 18 comprises a second portion 32 that is in flow communication with said second radial bore 20.

4. The governor shaft 12 as claimed in claims 2 and 3, wherein a diameter of said second portion is larger than a diameter of said first portion.

5. The governor shaft 12 as claimed in claim 1, further comprising a screw member 28 coupled to an end of said governor shaft 12, said screw member 28 removable to facilitate inserting said plug 22, said spring member 24, and said ball 26 within said governor shaft 12.

6. A governor 10 for a high pressure fuel pump 1, said governor 10 comprising at least a governor shaft 12, said governor shaft 12 comprising:
a body 14;
a first radial bore 16 defined in said body 14;
an axial bore 18 defined in said body 14 and in flow communication with said first radial bore 16, said axial bore 18 adapted to channel fuel that is supplied from said first radial bore 16 through said governor shaft 12;
a second radial bore 20 defined in said body 14 and in flow communication with said axial bore 18, said second radial bore 20 adapted to channel fuel that is delivered from said axial bore 18 out of said governor shaft 12;
characterized in that
a plug 22 positioned within said axial bore 18;
a spring member 24 inserted within said axial bore 18, a first end of said spring member 24 in contact with said plug 22; and
a ball 26 inserted within said axial bore 18, said ball 26 positioned against said spring member 24 such that said ball 26 closes said second radial bore 20 to prevent fuel flow through said governor shaft 12 until a pressure of fuel entering said governor shaft 12 is above a threshold fuel pressure.

7. A high pressure fuel pump 1, said high pressure fuel pump 1 comprising at least:
a governor 10, said governor 10 comprising at least a governor shaft 12, said governor shaft 12 comprising:
a body 14;
a first radial bore 16 defined in said body 14;
an axial bore 18 defined in said body 14 and in flow communication with said first radial bore 16, said axial bore 18 adapted to channel fuel that is supplied from said first radial bore 16 through said governor shaft 12;
a second radial bore 20 defined in said body 14 and in flow communication with said axial bore 18, said second radial bore 20 adapted to channel fuel that is delivered from said axial bore 18 out of said governor shaft 12; characterized in that
a plug 22 positioned within said axial bore 18;
a spring member 24 inserted within said axial bore 18, a first end of said spring member 24 in contact with said plug 22; and
a ball 26 inserted within said axial bore 18, said ball 26 positioned against said spring member 24 such that said ball 26 closes said second radial bore 20 to prevent fuel flow through said governor shaft 12 until a pressure of fuel entering said governor shaft 12 is above a threshold fuel pressure. , Description:Field of the invention:
[0001] This disclosure relates to a governor shaft of a high pressure fuel pump and a governor thereof.
Background of the invention:
[0002] U.S. Patent Number 5,086,742 describes a fuel injection pump for internal combustion engines. A centrifugal governor is driven in a known manner by a drive shaft of the pump piston. The rotations per minute of the drive shaft is transmitted to flyweights via a gear wheel supported on a holder. With increasing rotations per minute, centrifugal force comes into play, and the flyweights are moved outward. In this motion, each flyweight rotates about a respective knife-edge bearing, and via their inner shanks they displace the governor sleeve seated axially displaceably on the holder. The governor sleeve transmits its displacement motion in a known manner to the intermediate lever, which in turn varies the position of the governor slide relative to the control bore. The holder has an axial bore, which at one end discharges into the transverse bore disposed in the holder in the vicinity of the governor sleeve and at the other end communicates with the control line.

Brief description of the accompanying drawings:
[0003] An embodiment of the disclosure is described with reference to the following accompanying drawings:
[0004] Figure 1 illustrates a high pressure fuel pump in accordance with this disclosure;
[0005] Figure 2 illustrates a governor of the high pressure fuel pump in accordance with this disclosure; and
[0006] Figure 3 illustrates a governor shaft of the high pressure fuel pump in accordance with this disclosure.

Detailed description of the embodiments:
[0007] A governor shaft 12 for a governor 10 of a high pressure fuel pump 1 is described. The governor shaft 12 comprises a body 14, a first radial bore 16 defined in the body 14, and an axial bore 18 defined in the body 14 and in flow communication with the first radial bore 16, the axial bore 18 adapted to channel fuel that is supplied from the first radial bore 16 through the governor shaft 12. A second radial bore 20 defined in the body 14 and in flow communication with the axial bore 18, the second radial bore 20 adapted to channel fuel that is delivered from the axial bore 18 out of the governor shaft 12. A plug 22 is positioned within the axial bore 18, and a spring member 24 is inserted within the axial bore 18, a first end of the spring member 24 in contact with the plug 22. A ball 26 is inserted within the axial bore 18, the ball 26 positioned against the spring member 24 such that the ball 26 closes the second radial bore 20 to prevent fuel flow through the governor shaft 12 until a pressure of fuel entering the governor shaft 12 is above a threshold fuel pressure.

[0008] In addition, a governor 10 for a high pressure fuel pump 1 is described. The governor 10 comprises at least a governor shaft 12, the governor shaft 12 comprising a body 14, a first radial bore 16 defined in the body 14 and an axial bore 18 defined in the body 14 and in flow communication with the first radial bore 16, the axial bore 18 adapted to channel fuel that is supplied from the first radial bore 16 through the governor shaft 12. A second radial bore 20 is defined in the body 14 and in flow communication with the axial bore 18, the second radial bore 20 adapted to channel fuel that is delivered from the axial bore 18 out of the governor shaft 12. A plug 22 is positioned within the axial bore 18, and a spring member 24 is inserted within the axial bore 18, a first end of the spring member 24 in contact with the plug 22. A ball 26 is inserted within the axial bore 18, the ball 26 positioned against the spring member 24 such that the ball 26 closes the second radial bore 20 to prevent fuel flow through the governor shaft 12 until a pressure of fuel entering the governor shaft 12 is above a threshold fuel pressure.

[0009] A high pressure fuel pump 1 is also disclosed. The high pressure fuel pump 1 comprises a governor 10, the governor 10 comprising at least a governor shaft 12. The governor shaft 12 comprises a body 14, a first radial bore 16 defined in the body 14, and an axial bore 18 defined in the body 14 and in flow communication with the first radial bore 16, the axial bore 18 adapted to channel fuel that is supplied from the first radial bore 16 through the governor shaft 12. A second radial bore 20 is defined in the body 14 and in flow communication with the axial bore 18, the second radial bore 20 adapted to channel fuel that is delivered from the axial bore 18 out of the governor shaft 12. A plug 22 is positioned within the axial bore 18 and a spring member 24 is inserted within the axial bore 18, a first end of the spring member 24 in contact with the plug 22. A ball 26 is inserted within the axial bore 18, the ball 26 positioned against the spring member 24 such that the ball 26 closes the second radial bore 20 to prevent fuel flow through the governor shaft 12 until a pressure of fuel entering the governor shaft 12 is above a threshold fuel pressure.

[00010] Figure 1 illustrates a high pressure fuel pump 1. The high pressure fuel pump 1 includes a housing 8. A plunger 9 is positioned within the housing 8 such that the plunger 9 reciprocates within the housing 8. A vane pump 23 is coupled proximate to an inlet portion of the high pressure fuel pump 1. An internal bore 21 is coupled from an outlet portion of a governor shaft 12 of the high pressure fuel pump 1 to an inlet portion of the vane pump 23. The internal bore 21 facilitates channeling fuel that is supplied through an axial bore 18 defined in the governor shaft 12 to the inlet portion of the vane pump 23. In this manner, fuel from the body 14 of the governor 10 may be relieved in order to facilitate decreasing a pressure of fuel in the housing 8 of the high pressure fuel pump 1.

[00011] Figure 2 illustrates a governor 10 for the high pressure fuel pump 1. The governor 10 comprises a control lever 34 that may be moved from an idle position to a full throttle position. A spring member 36 is coupled between the control lever 34 and a tensioning lever 38. An idle spring 40 is coupled to the tensioning lever 38 and is operative during an idling condition of the engine. A start lever 42 is coupled to the tensioning lever 38 at a pivot 43. A dumbbell shaped rod 44 is coupled to the pivot 43 and extends to a control collar 46. More specifically, the dumbbell shaped rod 44 is inserted within the control collar 46 and facilitates translating the control collar 46 to facilitate discharging fuel out of a pumping chamber of the high pressure fuel pump 1. The start lever 42 is in contact with a sleeve portion 48 of the governor shaft 12. The start lever 42 facilitates moving the sleeve portion 48 of the governor shaft 12 to discharge fuel from the housing 8 of the high pressure fuel pump 1.

[00012] A first end of the sleeve portion 48 of the governor shaft 12 comprises a notched portion 37. Flyweights 49 and 50 are positioned within the governor 10 such that the flyweights 49 and 50 are positioned against the notched portion 37 of the sleeve portion 48 of the governor shaft 12. The flyweights 49 and 50 are coupled to a drive shaft 51 of the high pressure fuel pump 1. The governor shaft 12 is inserted within the sleeve portion 48 of the governor 10. When the drive shaft 51 of the high pressure fuel pump 1 rotates, the flyweights 49 and 50 are lifted thereby causing the flyweights 48 and 50 to press against the notched portion 37 of the sleeve portion 48. The force of the flyweights 49 and 50 against the notched portion 37 of the sleeve portion 48 causes the sleeve portion 48 to move in the forward direction. The sleeve portion 48 of the governor shaft 12 includes a first radial bore 17 defined therein. An outer portion of the first radial bore 17 is in flow communication with the fuel that is present within the housing 8 of the high pressure fuel pump 1. The governor shaft 12 includes the body 14 and an axial bore 18 that is defined in the body 14. The axial bore 18 that is defined in the body 14 is in flow communication with the radial bore 17 that is defined in the sleeve portion 48, when the sleeve portion 48 is moved in the forward direction to align with the radial bore 16 of the governor shaft 12. The body 14 of the governor shaft 12 includes a second radial bore 20 that is in flow communication with the axial bore 18. The second radial bore 20 delivers fuel out of the governor shaft 12 of the high pressure fuel pump 1. The axial bore 18 that is defined in the body 14 of the governor shaft 12 includes the radial bore 16 that is in flow communication with the radial bore 17 of the sleeve portion 48 when the sleeve portion 48 is moved in the forward direction by the flyweights 49 and 50 respectively. The internal bore 21 is coupled from an outlet portion of the governor shaft 12 of the high pressure fuel pump 1 to the inlet portion of the vane pump 23. The internal bore 21 facilitates channeling fuel that is supplied through an axial bore 18 defined in the governor shaft 12 to the inlet portion of the vane pump 23. In this manner, fuel from the body 14 of the governor 10 may be relieved in order to facilitate decreasing a pressure of fuel in the housing 8 of the high pressure fuel pump 1.

[00013] Figure 3 illustrates a governor shaft 12 for the high pressure fuel pump 1. The governor shaft 12 includes a first radial bore 16 that extends from an outer portion of the body 14 of the governor shaft 12 to an inner portion of the body 14 of the governor shaft 12. The axial bore 18 extends from the inner portion of the body 14 of the governor shaft 12 along the axis of the governor shaft 12. The axial bore 18 includes a first portion 30 and a second portion 32, wherein a diameter of the second portion 32 is larger than a diameter of the first portion 30. The second portion 32 of the axial bore 18 includes the second radial bore 20 that extends from the inner portion of the body 14 of the governor shaft 12 to the outer portion of the body 14 of the governor shaft 12.

[00014] The ball 26 is positioned at an interface of the first portion 30 and the second portion 32 such that the ball 26 covers the second radial bore 20 to prevent fuel flow through the governor shaft 12 of the high pressure fuel pump 1. The spring member 24 is positioned within the second portion 32 of the axial bore 18. More specifically, a first end of the spring member 24 is positioned against the ball 26, while an opposite second end of the spring member 24 is positioned against the plug 22. The plug 22 facilitates sealing the second portion 32 of the axial bore 18 to prevent fuel flow through the axial bore 18 of the high pressure fuel pump 1. In addition, a position of the plug 22 can be set by a user in order to achieve a desired level of preload on the spring member 24. In an alternate embodiment, any sealing member may be positioned within the second portion 32 of the axial bore 18 to facilitate sealing the governor shaft 12 of the high pressure fuel pump 1. A spring constant of the spring member 24 is selected such that the ball 26 overcomes a resistive force of the spring member 24 when a pressure in the axial bore 18 of the governor shaft 12 is above a threshold pressure. The second portion 32 of the axial bore 18 is in flow communication with the second radial bore 20. Moreover, the first portion 30 of the axial bore 18 is in flow communication with the first radial bore 16.

[00015] The working of the governor shaft 12 of the high pressure fuel pump 1 is described as an example. During an idling condition of the engine, the first radial bore 16 of the governor shaft 12 is aligned with the radial bore 17 of the governor sleeve portion 48. Therein fuel flows through the radial bore 17 of the governor sleeve portion 48 and into the first axial bore 16 of the governor shaft 12. The turbulence of the fuel flowing through the radial bore 16 of the governor shaft 12 causes the governor sleeve portion 48 of the governor shaft 12 to vibrate, thereby varying the position of the sleeve portion 48. The vibration of the governor shaft 12 affects the pressure of fuel that is delivered from the high pressure fuel pump 1. Therefore, it is required to prevent a flow of fuel to the axial bore 18 of the governor shaft 12. The ball 26 that is provided in the axial bore 18 of the governor shaft 12 facilitates closing the second radial bore 20 of the governor shaft 12. During idling conditions of the engine, the pressure of the fuel in the housing 8 of the high pressure fuel pump 1 is low. The low pressure of fuel in the housing 8 of the high pressure fuel pump 1 does not overcome the resistive force of the spring member 24. Therefore, the ball 26 remains in position, thereby closing the second radial opening 20 of the governor shaft 12. The closing of the second radial opening 20 of the governor shaft 12 prevents fuel from flowing through the governor shaft 12 of the high pressure fuel pump 1. As a result, the position of the sleeve portion 48 of the governor shaft 12 is held steady, thereby causing a steady position of the sleeve portion 48 which ensures no variation in fuel delivery from the high pressure fuel pump to the engine.

[00016] During normal working conditions of the engine, the first radial bore 16 of the governor shaft 12 is aligned with the radial bore 17 of the governor sleeve portion 48. Therein fuel flows through the radial bore 17 of the governor sleeve portion 48 and into the first axial bore 16 of the governor shaft 12. The pressure of the fuel flowing through the radial bore 17 of the governor sleeve portion 48 causes the ball 26 that is provided in the axial bore 18 of the governor shaft 12 to move against the resistive force of the spring member 24, thereby opening the second radial bore 20 of the governor shaft 12. The opening of the second radial bore 20 of the governor shaft 12 facilitates fuel flowing through the governor shaft 12 of the high pressure fuel pump 1.

[00017] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.