Claims:CLAIMS

We Claim

1. A maximum speed control unit (10) for a governor (20) of a high-pressure fuel pump (100), the maximum speed control unit (10) for the governor (20) of the high-pressure fuel pump (100) comprising:
a set-screw (12) positioned within a housing (14) of the high-pressure fuel pump (100) at one end, said set screw (12) adapted to abut against a control lever (17) at its opposite second end, the set-screw (12) adapted to be reciprocated within the housing (14) of the high-pressure fuel pump (100) by a user defined displacement to facilitate translating the control lever (16), thereby controlling a quantity of pressurized fuel that is delivered from the high-pressure fuel pump (100) to a fuel injector, said set-screw (12) comprising a plurality of external screw threads that are defined along a longitudinal shaft of said set-screw (12);
an adaptor (16) comprising a bore (18) defined therethrough, the bore (18) of said adaptor (16) secured to said set-screw (12) by screwing the external screw threads that are defined along the longitudinal shaft of said set-screw (12) to internal screw threads that are defined within the bore (18) of said adaptor (16);
the governor (20) comprising a bore (22) defined therethrough, the bore (22) of said governor (20) inserted through said adaptor (16) such that an end of said governor (20) is flush against an end of said adaptor (16);
a hexagonal bolt (24) comprising a bore (26) defined therethrough and a plurality of internal screw threads defined on the bore (26) of said hexagonal bolt (24), said hexagonal bolt (24) screwed on to the external screw threads that are defined on an outer diameter of said set-screw (12) such that an end of said hexagonal bolt (24) is flush against an end of said adaptor (16) and an end of said governor (20).

2. The maximum speed control unit (10) for a governor (20) of a high-pressure fuel pump (100) in accordance with Claim 1, further comprising a first lock-nut (28) comprising a bore (30) defined therethrough, the bore (30) of said first lock-nut (28) secured to said adaptor (16) by screwing external screw threads that are defined along a longitudinal shaft of said adaptor (16) to internal screw threads that are defined within the bore (30) of said first lock-nut (28).

3. The maximum speed control unit (10) for a governor (20) of a high-pressure fuel pump (100) in accordance with Claim 2, wherein said first lock-nut (28) secured to said adaptor (16) by screwing external screw threads that are defined along a longitudinal shaft of said adaptor (16) to internal screw threads that are defined within the bore (30) of said first lock-nut (28) prevents axial movement between said first lock-nut (28) and said adaptor (16).

4. The maximum speed control unit (10) for a governor (20) of a high-pressure fuel pump (100) in accordance with Claim 3, wherein said first lock-nut (28) when unscrewed from said adaptor (16) by unscrewing external screw threads that are defined along the longitudinal shaft of said adaptor (16) to internal screw threads that are defined within the bore (30) of said first lock-nut (28) facilitates axial translation between said first lock-nut (28) and said adaptor (16) to translate said adaptor (16) to a required axial length, thereby preventing said control lever (16) from rotating beyond a required angle of displacement.

5. The maximum speed control unit (10) for a governor (20) of a high-pressure fuel pump (100) in accordance with Claim 4, wherein said first lock-nut (28) is screwed to said adapter (16) by screwing external screw threads that are defined along the longitudinal shaft of said adapter (16) to internal screw threads that are defined within the bore (30) of said first lock-nut (28) to facilitate locking the adaptor (16) at a desired position, thereby preventing said control lever (16) from rotating beyond a required angle of displacement.

6. The maximum speed control unit (10) for a governor (20) of a high-pressure fuel pump (100) in accordance with Claim 1, further comprising a second lock-nut (31) comprising a bore (33) defined therethrough, the bore (33) of said second lock-nut (31) secured to said set-screw (12) by screwing external screw threads that are defined along a longitudinal shaft of said set-screw (12) to internal screw threads that are defined within the bore (33) of said second lock-nut (31).

7. The maximum speed control unit (10) for a governor (20) of a high-pressure fuel pump (100) in accordance with Claim 6, wherein said second lock-nut (31) secured to said set-screw (12) by screwing external screw threads that are defined along a longitudinal shaft of said set-screw (12) to internal screw threads that are defined within the bore (33) of said second lock-nut (31) prevents axial movement between said second lock-nut (31) and said set-screw (12).

8. The maximum speed control unit (10) for a governor (20) of a high-pressure fuel pump (100) in accordance with Claim 7, wherein said second lock-nut (31) is unscrewed from said set-screw (12) by unscrewing external screw threads that are defined along the longitudinal shaft of said set-screw (12) to internal screw threads that are defined within the bore (33) of said second lock-nut (28) to facilitate translating said set-screw (12) to a required axial length, thereby preventing said control lever (16) from rotating beyond a required angle of displacement.
9. The maximum speed control unit (10) for a governor (20) of a high-pressure fuel pump (100) in accordance with Claim 8, wherein said second lock-nut (31) is screwed to said set-screw (12) by screwing external screw threads that are defined along the longitudinal shaft of said set-screw (12) to internal screw threads that are defined within the bore (33) of said second lock-nut (31) to facilitate locking the set-screw (12) at a desired position, thereby preventing said control lever (16) from rotating beyond the required angle of displacement.
, Description:Complete Specification:

The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of the invention
[0001] This invention relates to a governor of a high-pressure fuel pump, and more specifically to a maximum speed control unit for the governor of the high-pressure fuel pump.

Background of the invention
[0002] GB 2295463 A1 describes a governor mechanism for a rotary fuel pump in an engine that comprises an adjustment mechanism which adjusts the number of active coils and prestresses, independently, and a governor spring. The mechanism adjusts the number of active coils via a screw which is in threaded engagement with an outer screw and has on one end helical grooves having a pitch equal to that of a spring. When the locking screw is released, the screw is rotated relative to the outer screw, resulting in a change in the number of active coils. Releasing the lock nut allows the outer screw to rotate relative to the housing, thereby adjusting the pre-stressing of the spring independently. Sealing rings are provided to restrict leakage. The spring acts on one end of the lever, the other end of which acts against a centrifugal weight mechanism. The lever is further connected to a fuel control member. Spring rotation, when adjusting, is restricted by a leg bearing against the housing.

Brief description of the accompanying drawing
[0003] Figure 1 illustrates a schematic representation of a maximum speed control unit for a governor of a high-pressure fuel pump.

Detailed description of the embodiments
[0004] Figure 1 illustrates a maximum speed control unit 10 for a governor 20 of a high-pressure fuel pump 100. The maximum speed control unit 10 for the governor 20 of the high-pressure fuel pump 100 comprises a set-screw 12 that is positioned within a housing of the high-pressure fuel pump 100 at one end. The set-screw 12 is adapted to abut against a control lever 17 at its opposite second end. The set-screw 12 is adapted to be reciprocated within the housing 14 of the high-pressure fuel pump 10 to facilitate controlling the control lever 17 by a user defined displacement, thereby controlling a quantity of pressurized fuel that is delivered from the high-pressure fuel pump 10 to a fuel injector. The set-screw 12 comprises a plurality of external screw threads that are defined along a longitudinal shaft of the set-screw 12. An adaptor 16 comprises a bore 18 defined therethrough. The bore 18 of the adaptor 16 is secured to the set-screw 12 by screwing the external screw threads that are defined along the longitudinal shaft of the set-screw 12 to internal screw threads that are defined within the bore 18 of the adaptor 16. A governor 20 comprises a bore 22 defined therethrough, the bore 22 of the governor 20 inserted through the adaptor 16 such that an end of the governor 20 is flush against an end of the adaptor 16. A hexagonal bolt 24 comprises a bore 26 defined therethrough and a plurality of internal screw threads defined on the bore 26 of the hexagonal bolt 24. The hexagonal bolt 24 is screwed on to the external screw threads that are defined on an outer diameter of the set-screw 12 such that an end of the hexagonal bolt 24 is flush against an end of the adaptor 16 and an end of the governor 20.

[0005] Figure 1 illustrates a maximum speed control unit 10 for a governor 20 of a high-pressure fuel pump 100. The maximum speed control unit 10 for the governor 20 of the high-pressure fuel pump 100 comprises a set-screw 12 that is positioned within a housing 14 of the high-pressure fuel pump 100 at its one end. More specifically, the set-screw 12 of the maximum speed control unit 10 is received within the housing 14 of the high-pressure fuel pump 100 at its one end, while abutting against a control lever 17 of the governor 20 at its opposite second end. In the exemplary embodiment, the set-screw 12 is adapted to be reciprocated within the housing 14 of the high-pressure fuel pump 100 to facilitate controlling a displacement of the control lever 17. More specifically, when the set-screw 12 is at one extreme position proximate to the control lever 17, the control lever 17 is at the minimum displacement angle position that corresponds to the minimum fueling quantity of the high-pressure fuel pump 10. Conversely, when the set-screw 12 is at the opposite extreme position away from the control lever 17, the control lever 17 is at the maximum displacement angle position that corresponds to the maximum fueling quantity of the high-pressure fuel pump 10. Therefore, the position of the set-screw 12 with respect to the control lever 17 facilitates controlling a quantity of pressurized fuel that is delivered from the high-pressure fuel pump 10 to a fuel injector.

[0006] In the exemplary embodiment, the set-screw 12 comprises a plurality of external screw threads that are defined along a longitudinal shaft of the set-screw 12. An adaptor 16 comprises a bore 18 that is defined therethrough, wherein the adaptor 16 comprises a plurality of internal screw threads that are defined along the longitudinal axis of the adaptor 16. The set-screw 12 is secured within the bore 18 of the adaptor 16 by screwing the external screw threads that are defined along the longitudinal shaft of the set-screw 12 to internal screw threads that are defined within the bore 18 of the adaptor 16. When the set-screw 12 is completely screwed within the bore 18 of the adaptor 16, the longitudinal shaft of the set-screw 12 is completely positioned within the bore 18 of the adaptor 16. A governor 20 comprises a bore 22 defined therethrough. The bore 22 of the governor 20 is inserted through the adaptor 16 such that an end of the governor 20 is flush against an end of the adaptor 16. More specifically, the bore 22 that is defined in the governor 20 is positioned on the adaptor 16 and inserted through the adaptor 16 such that the end of the governor 20 is flush against the end of the adaptor 16.

[0007] In an exemplary embodiment, a hexagonal bolt 24 comprises a bore 26 defined therethrough and a plurality of internal screw threads that are defined on the bore 26 of the hexagonal bolt 24. The bore 26 of the hexagonal bolt 24 is positioned on the set-screw 12 and screwed on to the external screw threads that are defined on the outer diameter of the set-screw 12. More specifically, the internal screw threads that are defined in the bore 26 of the hexagonal bolt 24 meshes with the external screw threads that are defined on the outer diameter of the set-screw 12 when the hexagonal bolt 24 is screwed on to the set-screw 12 such that the end of the hexagonal bolt 24 is flush against an end of the adaptor 16 and against an end of the governor 20 respectively. Therefore, the hexagonal bolt 24 facilitates securing the set-screw 12, the adaptor 16, and the governor 20 in a unitary assembly, thereby preventing the set-screw 12, the adaptor 16, and the governor 20 from translating relative to one other.

[0008] In an exemplary embodiment, a first lock-nut 28 comprises a bore 30 defined therethrough. The bore 30 of the first lock-nut 28 is secured to the adaptor 16 by screwing external screw threads that are defined along a longitudinal shaft of the adaptor 16 to internal screw threads that are defined within the bore 30 of the first lock-nut 28. Therefore, the first lock-nut 28 is screwed on to the longitudinal shaft of the adaptor 16 by screwing the first lock-nut 28 along the entire span of the outer diameter of the adaptor 16. When the first lock-nut 28 is secured to the adaptor 16 by screwing external screw threads that are defined along the longitudinal shaft of the adaptor 16 to internal screw threads that are defined within the bore 30 of the first lock- nut 28, the first lock-nut 28 is flush against an end of the governor 20. The first lock-nut 28 that is screwed on to the longitudinal shaft of the adaptor 16 and is flush against the governor 20 prevents axial movement between the first lock-nut 28 and the adaptor 16. Conversely, when the first lock-nut 28 is unscrewed from the adaptor 16 by unscrewing external screw threads that are defined along the longitudinal shaft of the adaptor 16 to internal screw threads that are defined within the bore 30 of the first lock-nut 28, axial translation between the first lock-nut 28 and the adaptor 16 is facilitated. Once the first lock-nut 28 is unscrewed from the adaptor 16, the adaptor 16 may be translated to a required axial length in a direction towards the control lever 17. The translation of the adaptor 16 to the required axial length in the direction of the control lever 17 prevents the control lever 17 from rotating beyond a required angle of displacement towards the maximum speed control unit 10.

[0009] In an exemplary embodiment, the first lock-nut 28 is screwed to the adapter 16 by screwing external screw threads that are defined along the longitudinal shaft of the adapter 16 to internal screw threads that are defined within the bore 30 of the first lock-nut 28. By screwing the external screw threads that are defined along the longitudinal shaft of the adapter 16 to internal screw threads that are defined within the bore 30 of the first lock-nut 28, the governor 20 may be locked at a desired position. The locking of the governor 20 at the desired position prevents the control lever 17 from being rotated beyond the required angle of displacement such that the control lever 17 abuts against an end of the set-screw 12. In an exemplary embodiment, a second lock-nut 31 comprising a bore 33 is defined therethrough. More specifically, the bore 33 of the second lock-nut 31 is secured to the set-screw 12 by screwing external screw threads that are defined along the longitudinal shaft of the set-screw 12 to internal screw threads that are defined within the bore 33 of the second lock nut 31.

[0010] In an exemplary embodiment, the second lock-nut 31 is secured to the set-screw 12 by screwing external screw threads that are defined along a longitudinal shaft of the set-screw 12 to internal screw threads that are defined within the bore 33 of the second lock-nut 31. By screwing the external screw threads that are defined along the longitudinal shaft of the set-screw 12 to internal screw threads that are defined within the bore 33 of the second lock-nut 31, the set-screw 12 may be locked at a desired position. The locking of the set-screw 12 at the desired position prevents the control lever 17 from being rotated beyond the required angle of displacement such that the control lever 17 abuts against an end of the set-screw 12. Therefore, by translating the adaptor 16 to the user desired position by loosening the first lock-nut 28 and translating the set-screw 12 to the user desired position by loosening the second lock-nut 31, the overall length of travel of the set-screw 12 may be increased. Moreover, since the set-screw 12 is positioned within the adaptor 16, the adaptor 16 facilitates increasing the shear stability of the set-screw 12 due to an increase in diameter of the adaptor 16 and set-screw 12 assembly. Consequently, the adaptor 16 and set-screw 12 assembly has an increased resistance to shear stress that is caused due to the abutment of the control lever 17 against the set-screw 12.

[0011] The second lock-nut 31 is unscrewed from the set-screw 12 by unscrewing external screw threads that are defined along the longitudinal shaft of the set-screw 12 to internal screw threads that are defined within the bore 33 of the second lock-nut 31. When the second lock-nut 31 is unscrewed from the set-screw 12 completely, the set-screw 12 is translated to a required axial length that corresponds to the required fueling quantity of the high-pressure fuel pump 100. When the set-screw 12 is translated to this required axial length, the control lever 17 is prevented from being rotated beyond the required angle of displacement. At the required angle of displacement, the set-screw 12 abuts against the end of the control lever 17, and prevents the control lever 17 from being rotated any further. In an exemplary embodiment, the second lock-nut 31 is screwed to the set-screw 12 by screwing external screw threads that are defined along the longitudinal shaft of the set-screw 12 to internal screw threads that are defined within the bore 33 of the second lock-nut 31, to facilitate locking the set-screw 12 at the user desired position. When the set-screw 12 is locked at the user desired position, the control lever 17 is prevented from being rotated beyond the required angle of displacement. Due to the control lever 17 being prevented from being rotated beyond the required angle of displacement, the required fueling quantity of pressurized fuel that is delivered from the element chamber of the high-pressure fuel pump 100 to the fuel injector may be effectively controlled.

[0012] Once the set-screw 12 is translated to the required axial displacement, the second lock-nut 31 is screwed to the set-screw 12 by screwing external screw threads that are defined along the longitudinal shaft of the set-screw 12 to internal screw threads that are defined within the bore 33 of the second lock-nut 31. When the second lock-nut 31 is screwed to the set-screw 12 by screwing external screw threads that are defined along the longitudinal shaft of the set-screw 12 to internal screw threads that are defined within the bore 33 of the second lock-nut 31, the set-screw 12 is locked at the user desired position, thus preventing the control lever 17 from rotating beyond the required angle of displacement. Similarly, the first lock-nut 28 is also secured to the adaptor 16 by tightening the first lock-nut 28 once the adaptor 16 has been translated to the user desired displacement.

{0013] As described earlier, when the set-screw 12 is positioned within the adaptor 16 and translated in the direction of the control lever 17, the adaptor 16 acts like an outer sheath. Thereby, the adaptor 16 facilitates providing structural rigidity to the set-screw 12, thereby preventing the set-screw 12 from bending due to the shear loads that act on the set-screw 12 due to the control lever 17 applying a shear force on the set-screw 12.

[0014] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to dimensions of various components are envisaged and form a part of this invention. The scope of the invention is only limited by the scope of the claims.