US20200018296A1 - Tappet body and fuel injection pump comprising same - Google Patents
Tappet body and fuel injection pump comprising same Download PDFInfo
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- US20200018296A1 US20200018296A1 US16/505,882 US201916505882A US2020018296A1 US 20200018296 A1 US20200018296 A1 US 20200018296A1 US 201916505882 A US201916505882 A US 201916505882A US 2020018296 A1 US2020018296 A1 US 2020018296A1
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- US
- United States
- Prior art keywords
- tappet body
- injection pump
- face
- inner end
- fuel injection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B7/00—Piston machines or pumps characterised by having positively-driven valving
- F04B7/0057—Mechanical driving means therefor, e.g. cams
- F04B7/0069—Mechanical driving means therefor, e.g. cams for a sliding member
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
- F04B1/04—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement
- F04B1/0404—Details or component parts
- F04B1/0426—Arrangements for pressing the pistons against the actuated cam; Arrangements for connecting the pistons to the actuated cam
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
- F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
- F02M59/02—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type
- F02M59/10—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type characterised by the piston-drive
- F02M59/102—Mechanical drive, e.g. tappets or cams
Definitions
- the present application relates to a fuel feed system of an internal combustion engine, and in particular to a tappet body and a fuel injection pump comprising same.
- a fuel feed system using a common rail system typically comprises a fuel injection pump device, a common rail system, and a plurality of fuel injection valves.
- the fuel injection pump device is used for pumping fuel from a fuel tank and pressurizing the fuel to deliver same to the common rail system.
- the common rail system is used for storing high-pressure fuel from the fuel injection pump device.
- Each of the fuel injection valves is disposed within a corresponding one of a plurality of cylinders of an internal combustion engine such that the high-pressure fuel in the common rail system is fed to respective cylinders.
- a fuel injection pump device 1 in the prior art comprises a fuel injection pump 9 .
- the existing fuel injection pump 9 comprises: a shell 19 , which is formed with one upright hole 21 or two upright holes 21 arranged side by side and a chamber 28 in communication with the upright holes 21 ; plunger sleeves 13 , which are assembled in the upright holes 21 , wherein plungers 11 capable of moving in a reciprocating manner therein are respectively inserted in the plunger sleeves 13 ; and a camshaft 17 , which is rotatably supported, wherein the camshaft 17 is formed with drive cams 25 , 27 which correspond to the plungers 11 and are located in the chamber 28 .
- a lower end of the plunger 11 is placed on a corresponding tappet body 15 .
- a first cavity 29 is formed on the side of a tappet body 15 that faces the drive cam 25 , 27 .
- a roller 33 is held in the first cavity 29 by a pin shaft 31 which is mounted on the tappet body 15 in such a way that the roller is scrollable about the pin shaft 31 and axially movable along the pin shaft 31 .
- a spring 35 and a spring seat 36 are further provided between the plunger sleeve 13 and the tappet body 15 .
- a second cavity 30 is formed on the side of the tappet body 15 that is away from the drive cam 25 , 27 , and the spring seat 36 is accommodated within the second cavity 30 .
- One side of the spring seat 36 is in contact with the spring 35 , and the other side thereof is in contact with an inner end face 47 of the tappet body 15 (i.e., an inner end face of the second cavity 30 ).
- the spring 35 biases the tappet body 15 towards the camshaft 17 by the spring seat 36 such that the roller 33 is always in contact with corresponding drive cam 25 , 27 .
- the plunger 11 moves in a reciprocating manner up and down against an outer contour of the drive cam 25 , 27 by the roller 33 held on the tappet body 15 as a contour position of the drive cam 25 , 27 changes.
- left and right side end faces of the roller 33 of the tappet body 15 are twisted and thus come into contact with left and right inner side faces of the first cavity 29 of the tappet body 15 , and friction is caused. Such friction may lead to wear of the left and right side end faces of the roller 33 and the left and right inner side faces of the first cavity 29 of the tappet body 15 , which shortens the service life of the tappet body 15 and the roller 33 held on same.
- An object of the present application is to overcome the above-mentioned defects in the prior art and to provide a tappet body and a fuel injection pump comprising same.
- a tappet body for a fuel injection pump comprising: a first cavity, which is disposed at the bottom of the tappet body; a roller, which is held in the first cavity by a pin shaft in such a way that the roller is scrollable and axially movable; and a second cavity, which is disposed at the top of the tappet body and has an inner end face perpendicular to a longitudinal central axis of the tappet body; wherein at least one recess symmetrical about the longitudinal central axis of the tappet body is provided in the inner end face.
- the at least one recess is an annular recess and is configured such that at least part of the recess is at a position of the inner end face that is proximate to an outer perimeter of the inner end face.
- the distance between the at least part of the annular recess and the longitudinal central axis of the tappet body is greater than one third of the radius of the inner end face.
- the at least one recess includes a plurality of radial recesses or dispersedly-arranged recesses and is configured such that at least part of the recesses is at a position of the inner end face that is proximate to an outer perimeter of the inner end face.
- the distance between the at least part of the plurality of radial recesses or dispersedly-arranged recesses and the longitudinal central axis of the tappet body is greater than one third of the radius of the inner end face.
- a central protrusion is further provided on the inner end face, and the at least one recess is disposed around the central protrusion.
- a through hole for communication between the first cavity and the second cavity is provided in the tappet body, and the width of the at least one recess is greater than the diameter of the through hole.
- a fuel injection pump comprising the tappet body.
- the fuel injection pump further comprises:
- a plunger sleeve which is fixedly assembled in the upright hole, wherein a plunger is inserted in the plunger sleeve, and the plunger is placed on the tappet body and is capable of moving in a reciprocating manner in the plunger sleeve;
- camshaft which is rotatably supported by the injection pump shell, wherein the camshaft is formed with a drive cam which corresponds to the plunger and located in the chamber;
- a spring and a spring seat which are disposed between the plunger sleeve and the tappet body, the spring biasing a roller of the tappet body onto the drive cam by the spring seat;
- a fuel inlet and discharge valve assembly which is disposed at an upper end of the plunger sleeve and is configured to allow fuel to be pumped into the fuel injection pump with the rotation of the camshaft and to further pressurize the fuel pumped into the fuel injection pump for ejection.
- the tappet body according to the present application can greatly reduce the contact area between the spring seat and the tappet body, thereby greatly reducing the wear, which is caused by friction, of left and right side end faces of the roller and left and right inner sides of the first cavity of the tappet body, and prolonging the service life of the tappet body and the roller held on same.
- FIG. 1 illustrates a longitudinal sectional view of a fuel injection pump device in the prior art for showing the structure in a pump body of a fuel injection pump;
- FIGS. 2 and 3 respectively illustrate a partial cutaway perspective view and a sectional view of a tappet body in the prior art
- FIG. 4 illustrates a longitudinal sectional view of a fuel injection pump device according to an embodiment of the present application
- FIGS. 5 and 6 respectively illustrate a partial cutaway perspective view and a sectional view of a tappet body according to an embodiment of the present application.
- a fuel injection pump device 1 generally comprises a vane pump 3 , a fuel metering unit 5 , an overflow valve 7 and a fuel injection pump 9 which are assembled together.
- the vane pump 3 pumps fuel from a fuel tank and delivers the fuel to the fuel metering unit 5 .
- the fuel metering unit 5 can adjust the amount of fuel to be supplied to the fuel injection pump 9 .
- the fuel supplied to the fuel injection pump 9 is pressurized and then ejected, so that the fuel flows to a common rail system.
- the fuel is then delivered from the common rail system to various fuel injection valves.
- the overflow valve 7 can take an action to discharge part of the fuel from the fuel injection pump 9 .
- the fuel injection pump device 1 can further comprise a relief valve for returning part of the fuel to the fuel tank.
- the fuel injection pump 9 comprises two plungers 11 , corresponding plunger sleeves 13 , corresponding tappet bodies 15 , and a camshaft 17 .
- the camshaft 17 is supported on an injection pump shell 19 with one end of the camshaft 17 protruding through the injection pump shell 19 to receive a driving torque from an engine (not shown), so that the camshaft 17 rotates synchronously with the engine.
- the injection pump shell 19 comprises an injection pump shell component 19 a and an injection pump shell component 19 b .
- the injection pump shell component 19 b and a vane pump shell are mounted to both ends of the injection pump shell component 19 a by bolts or similar devices.
- the camshaft 17 is rotatably held on the injection pump shell 19 by a bearing 23 .
- Two upright holes 21 are formed in the injection pump shell component 19 a .
- Drive cams 25 and 27 which are respectively used for the respective plungers 11 , are formed on the camshaft 17 and are located in a chamber 28 , which is below the upright holes 21 and is formed within the injection pump shell component 19 a .
- the injection pump shell component 19 a may also be formed with only one upright hole 21 .
- the plunger sleeves 13 are fixedly assembled in the corresponding upright holes 21 .
- the plungers 11 are respectively inserted in the plunger sleeves 13 .
- a lower end of the plunger 11 is placed on the corresponding tappet body 15 so as to move in a reciprocating manner in the plunger sleeve 13 .
- the specific structure of the tappet body 15 will be described in detail below in combination with FIGS. 5 and 6 .
- a fuel inlet and discharge valve assembly 37 is provided at an upper end of the plunger sleeve 13 .
- a plunger chamber 39 is formed between the fuel inlet and discharge valve assembly 37 and the respective plunger 11 .
- a fuel injection channel 43 formed in a valve holder 41 is located above the fuel inlet and discharge valve assembly 37 .
- the specific structure of the fuel inlet and discharge valve assembly 37 is commonly known in the art, and thus the detailed description thereof is omitted.
- a positive pressure is formed in the plunger chamber 39 corresponding to the plunger, and the fuel inlet and discharge valve assembly 37 is opened in a commonly known manner so that the fuel is ejected from the fuel injection channel 43 and delivered to the common rail system.
- the process is performed alternately and repeatedly to continuously deliver the fuel to the common rail system.
- FIGS. 5 and 6 are respectively a partial cutaway perspective view and a sectional view of a tappet body according to an embodiment of the present application, wherein a roller is mounted in the tappet body.
- the tappet body 15 is substantially cylindrical in shape and has a longitudinal central axis.
- First cavities 29 are formed on the side of each of the tappet bodies 15 that faces the drive cams 25 and 27 (i.e., the bottom of each of the tappet bodies 15 ).
- Rollers 33 are held in the first cavities 29 by pin shafts 31 which are mounted on the tappet bodies 15 in such a way that the rollers are scrollable about the pin shafts 31 and axially movable along the pin shafts 31 .
- Second cavities 30 are formed on the side of each of the tappet bodies 15 that is opposite the drive cams 25 and 27 (i.e., the top of each of the tappet bodies 15 ).
- Central protrusions 16 are provided within the second cavities 30 .
- Inner end faces 47 perpendicular to longitudinal central axes of the tappet bodies 15 are formed around the central protrusions 16 , wherein at least one recess 38 (e.g., annular recess) is formed in the inner end face 47 in such a way that the recess surrounds the central protrusion 16 and is symmetrical about the longitudinal central axis of the tappet body 15 .
- the tappet body 15 may also be not provided with the central protrusion 16 so that the inner end face 47 is a generally circular surface.
- a spring 35 and a spring seat 36 are further provided between the plunger sleeve 13 and the tappet body 15 .
- the spring seat 36 is accommodated within the second cavity 30 , and one side of the spring seat 36 (i.e., an upper side) is in contact with the spring 35 and the other side (i.e., a lower side) is in contact with the inner end face 47 of the tappet body 15 .
- the spring 35 biases the tappet body 15 towards the camshaft 17 by the spring seat 36 such that the rollers 33 are always in contact with corresponding drive cams 25 and 27 .
- the drive cams 25 and 27 drive the tappet body 15 to move up and down, thereby driving the plunger 11 and the plunger sleeve 13 to move up and down.
- the spring 35 is located between the spring seat 36 and the plunger sleeve 13 , the spring 35 is compressed and elongated repeatedly. In the process that the spring 35 is compressed and elongated, the spring 35 generates a torque due to inherent properties thereof, which accordingly drives the spring seat 36 to twist.
- the lower side of the spring seat 36 is in contact with the inner end face 47 of the tappet body 15 .
- the torque generated by the spring 35 is transmitted to the tappet body 15 by means of friction between the spring seat 36 and the tappet body 15 , driving the tappet body 15 to twist.
- the recess 38 is provided in the inner end face 47 , only part of the lower side of the spring seat 36 is in contact with the inner end face 47 , rather than all of the lower side of the spring seat 36 is in contact with the inner end face 47 .
- the contact area between the spring seat 36 and the inner end face 47 of the tappet body 15 is greatly reduced and thus the frictional force between them is reduced, which mitigates the friction between left and right side end faces of the roller 33 of the tappet body 15 and the inner end face of the tappet body.
- the recess 38 is an annular recess and is configured such that at least part of the annular recess is at a position of the inner end face 47 proximate to an outer perimeter of the inner end face 47 , i.e., the distance between the at least part of the annular recess and the longitudinal central axis of the tappet body 15 is greater than a half of the radius of the inner end face 47 .
- This is because an annular contact part proximate to the outer perimeter of the inner end face 47 is often formed due to the contact between the lower side of the spring seat 36 and the inner end face 47 .
- the contact area between the spring seat and the tappet body can be reduced provided that the recess 38 is disposed in the part of the inner end face 47 that is in contact with the spring seat 36 . Furthermore, considering the moment caused by the frictional force, disposing the recess 38 at a position of the inner end face 47 that is proximate to the outer perimeter thereof can better reduce the torque transmitted to the tappet body.
- the distance between the at least part of the annular recess and the longitudinal central axis of the tappet body 15 is greater than one third of the radius of the inner end face 47 .
- the recess 38 can include a plurality of radial recesses or dispersedly-arranged recesses, and is configured such that at least part of the plurality of radial recesses or dispersedly-arranged recesses is at the position of the inner end face 47 that is proximate to the outer perimeter of the inner end face 47 , i.e., the distance between the at least part of the plurality of radial recesses or dispersedly-arranged recesses and the longitudinal central axis of the tappet body 15 is greater than a half of the radius of the inner end face 47 . Preferably, the distance is greater than one third of the radius of the inner end face 47 .
- the tappet body 15 can be further provided with at least two through holes 48 for communication between the first cavity 29 and the second cavity 30 , so as to maintain the pressure balance between the two cavities.
- the width of the recess 38 can be greater than the diameter of the through hole 48 to reduce the contact area between the spring seat and the tappet body and to facilitate machining.
- a solution in which the width and depth of the recess 38 can be further adjusted according to the size of the tappet body and the spring seat is further envisaged in the present application, but is not described in further detail herein.
- the contact area between the spring seat and the tappet body can be greatly reduced, thus greatly reducing the wear, which is caused by friction, of the left and right side end faces of the roller and the left and right inner side faces of the first cavity of the tappet body, and prolonging the service life of the tappet body and the roller held on same.
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- Engineering & Computer Science (AREA)
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- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
Description
- The present application relates to a fuel feed system of an internal combustion engine, and in particular to a tappet body and a fuel injection pump comprising same.
- Fuel feed systems of internal combustion engines are commonly known. A fuel feed system using a common rail system typically comprises a fuel injection pump device, a common rail system, and a plurality of fuel injection valves. Here, the fuel injection pump device is used for pumping fuel from a fuel tank and pressurizing the fuel to deliver same to the common rail system. The common rail system is used for storing high-pressure fuel from the fuel injection pump device. Each of the fuel injection valves is disposed within a corresponding one of a plurality of cylinders of an internal combustion engine such that the high-pressure fuel in the common rail system is fed to respective cylinders.
- Referring to
FIGS. 1, 2 and 3 , a fuel injection pump device 1 in the prior art comprises a fuel injection pump 9. The existing fuel injection pump 9 comprises: ashell 19, which is formed with oneupright hole 21 or twoupright holes 21 arranged side by side and achamber 28 in communication with theupright holes 21;plunger sleeves 13, which are assembled in theupright holes 21, wherein plungers 11 capable of moving in a reciprocating manner therein are respectively inserted in theplunger sleeves 13; and acamshaft 17, which is rotatably supported, wherein thecamshaft 17 is formed withdrive cams plungers 11 and are located in thechamber 28. A lower end of theplunger 11 is placed on acorresponding tappet body 15. Afirst cavity 29 is formed on the side of atappet body 15 that faces thedrive cam roller 33 is held in thefirst cavity 29 by apin shaft 31 which is mounted on thetappet body 15 in such a way that the roller is scrollable about thepin shaft 31 and axially movable along thepin shaft 31. Aspring 35 and aspring seat 36 are further provided between theplunger sleeve 13 and thetappet body 15. Asecond cavity 30 is formed on the side of thetappet body 15 that is away from thedrive cam spring seat 36 is accommodated within thesecond cavity 30. One side of thespring seat 36 is in contact with thespring 35, and the other side thereof is in contact with aninner end face 47 of the tappet body 15 (i.e., an inner end face of the second cavity 30). Thespring 35 biases thetappet body 15 towards thecamshaft 17 by thespring seat 36 such that theroller 33 is always in contact withcorresponding drive cam camshaft 17 rotates, theplunger 11 moves in a reciprocating manner up and down against an outer contour of thedrive cam roller 33 held on thetappet body 15 as a contour position of thedrive cam - However, in the process of moving up and down with the
tappet body 15, due to inherent properties of a coil spring, repeated compression and elongation of thespring 35 may cause the spring to twist, generating a torque to thespring seat 36 and thereby generating a torque to thetappet body 15 by the friction between thespring seat 36 and theinner end face 47 of thetappet body 15. Since theinner end face 47 of thetappet body 15 is an annular plane disposed around acentral protrusion 16, the contact area between thespring seat 36 and theinner end face 47 of thetappet body 15 is relatively large, so that the frictional force between them is also relatively large. As a result, left and right side end faces of theroller 33 of thetappet body 15 are twisted and thus come into contact with left and right inner side faces of thefirst cavity 29 of thetappet body 15, and friction is caused. Such friction may lead to wear of the left and right side end faces of theroller 33 and the left and right inner side faces of thefirst cavity 29 of thetappet body 15, which shortens the service life of thetappet body 15 and theroller 33 held on same. - Therefore, there is a need to improve the tappet body in the prior art.
- An object of the present application is to overcome the above-mentioned defects in the prior art and to provide a tappet body and a fuel injection pump comprising same.
- According to an aspect of the present application, provided is a tappet body for a fuel injection pump, the tappet body comprising: a first cavity, which is disposed at the bottom of the tappet body; a roller, which is held in the first cavity by a pin shaft in such a way that the roller is scrollable and axially movable; and a second cavity, which is disposed at the top of the tappet body and has an inner end face perpendicular to a longitudinal central axis of the tappet body; wherein at least one recess symmetrical about the longitudinal central axis of the tappet body is provided in the inner end face.
- According to an embodiment, the at least one recess is an annular recess and is configured such that at least part of the recess is at a position of the inner end face that is proximate to an outer perimeter of the inner end face.
- According to an embodiment, the distance between the at least part of the annular recess and the longitudinal central axis of the tappet body is greater than one third of the radius of the inner end face.
- According to an embodiment, the at least one recess includes a plurality of radial recesses or dispersedly-arranged recesses and is configured such that at least part of the recesses is at a position of the inner end face that is proximate to an outer perimeter of the inner end face.
- According to an embodiment, the distance between the at least part of the plurality of radial recesses or dispersedly-arranged recesses and the longitudinal central axis of the tappet body is greater than one third of the radius of the inner end face.
- According to an embodiment, a central protrusion is further provided on the inner end face, and the at least one recess is disposed around the central protrusion.
- According to an embodiment, a through hole for communication between the first cavity and the second cavity is provided in the tappet body, and the width of the at least one recess is greater than the diameter of the through hole.
- According to another aspect of the present application, a fuel injection pump comprising the tappet body is provided.
- According to an embodiment, the fuel injection pump further comprises:
-
- an injection pump shell, which is formed with at least one upright hole and a chamber in communication with the upright hole, wherein the tappet body is disposed in the upright hole;
- a plunger sleeve, which is fixedly assembled in the upright hole, wherein a plunger is inserted in the plunger sleeve, and the plunger is placed on the tappet body and is capable of moving in a reciprocating manner in the plunger sleeve;
- a camshaft, which is rotatably supported by the injection pump shell, wherein the camshaft is formed with a drive cam which corresponds to the plunger and located in the chamber;
- a spring and a spring seat, which are disposed between the plunger sleeve and the tappet body, the spring biasing a roller of the tappet body onto the drive cam by the spring seat; and
- a fuel inlet and discharge valve assembly, which is disposed at an upper end of the plunger sleeve and is configured to allow fuel to be pumped into the fuel injection pump with the rotation of the camshaft and to further pressurize the fuel pumped into the fuel injection pump for ejection.
- The positive effects of the present application are: the tappet body according to the present application can greatly reduce the contact area between the spring seat and the tappet body, thereby greatly reducing the wear, which is caused by friction, of left and right side end faces of the roller and left and right inner sides of the first cavity of the tappet body, and prolonging the service life of the tappet body and the roller held on same.
- The foregoing and other aspects of the present application will be more fully understood from the following detailed description in combination with the following drawings. It is noted that the proportion in the drawings may be different for the purpose of clarity, but this does not affect the understanding of the present application. In the drawings:
-
FIG. 1 illustrates a longitudinal sectional view of a fuel injection pump device in the prior art for showing the structure in a pump body of a fuel injection pump; -
FIGS. 2 and 3 respectively illustrate a partial cutaway perspective view and a sectional view of a tappet body in the prior art; -
FIG. 4 illustrates a longitudinal sectional view of a fuel injection pump device according to an embodiment of the present application; -
FIGS. 5 and 6 respectively illustrate a partial cutaway perspective view and a sectional view of a tappet body according to an embodiment of the present application. - In the figures of the present application, features with the same structures or similar functions are denoted by the same reference signs.
- Description of Reference Signs: fuel injection pump device 1;
vane pump 3; fuel metering unit 5; overflow valve 7; fuel injection pump 9;plunger 11;plunger sleeve 13;tappet body 15;central protrusion 16;camshaft 17;injection pump shell 19; injectionpump shell component 19 a; injection pump shell component 19 b;upright hole 21; bearing 23;drive cams chamber 28;first cavity 29;second cavity 30;pin shaft 31;roller 33;spring 35;spring seat 36; fuel inlet anddischarge valve assembly 37;recess 38;plunger chamber 39;valve holder 41; fuel injection channel 43; side end face 45;inner end face 47; throughhole 48. - Preferred embodiments of the present application are described in detail below in combination with examples. It should be understood by those skilled in the art that the exemplary embodiments are not intended to limit the present application in any manner.
- The structure and working process of the fuel injection pump device of the present application are generally described in combination with
FIG. 4 below. As shown inFIG. 4 , a fuel injection pump device 1 according to an embodiment of the present application generally comprises avane pump 3, a fuel metering unit 5, an overflow valve 7 and a fuel injection pump 9 which are assembled together. Thevane pump 3 pumps fuel from a fuel tank and delivers the fuel to the fuel metering unit 5. The fuel metering unit 5 can adjust the amount of fuel to be supplied to the fuel injection pump 9. The fuel supplied to the fuel injection pump 9 is pressurized and then ejected, so that the fuel flows to a common rail system. The fuel is then delivered from the common rail system to various fuel injection valves. In the case that the pressure of the fuel supplied to the fuel injection pump 9 exceeds a predetermined pressure, the overflow valve 7 can take an action to discharge part of the fuel from the fuel injection pump 9. In addition, the fuel injection pump device 1 can further comprise a relief valve for returning part of the fuel to the fuel tank. - The fuel injection pump 9 comprises two
plungers 11,corresponding plunger sleeves 13,corresponding tappet bodies 15, and acamshaft 17. The camshaft 17 is supported on aninjection pump shell 19 with one end of thecamshaft 17 protruding through theinjection pump shell 19 to receive a driving torque from an engine (not shown), so that thecamshaft 17 rotates synchronously with the engine. - The
injection pump shell 19 comprises an injectionpump shell component 19 a and an injection pump shell component 19 b. The injection pump shell component 19 b and a vane pump shell are mounted to both ends of the injectionpump shell component 19 a by bolts or similar devices. Thecamshaft 17 is rotatably held on theinjection pump shell 19 by abearing 23. Twoupright holes 21 are formed in the injectionpump shell component 19 a. Drivecams respective plungers 11, are formed on thecamshaft 17 and are located in achamber 28, which is below the upright holes 21 and is formed within the injectionpump shell component 19 a. It is noted that the injectionpump shell component 19 a may also be formed with only oneupright hole 21. Theplunger sleeves 13 are fixedly assembled in the corresponding upright holes 21. Theplungers 11 are respectively inserted in theplunger sleeves 13. A lower end of theplunger 11 is placed on thecorresponding tappet body 15 so as to move in a reciprocating manner in theplunger sleeve 13. The specific structure of thetappet body 15 will be described in detail below in combination withFIGS. 5 and 6 . - As shown in
FIG. 4 , a fuel inlet and dischargevalve assembly 37 is provided at an upper end of theplunger sleeve 13. Aplunger chamber 39 is formed between the fuel inlet and dischargevalve assembly 37 and therespective plunger 11. A fuel injection channel 43 formed in avalve holder 41 is located above the fuel inlet and dischargevalve assembly 37. The specific structure of the fuel inlet and dischargevalve assembly 37 is commonly known in the art, and thus the detailed description thereof is omitted. - When one of the plungers moves downwards as a lobe position of one of the drive cams (e.g., the
drive cam 27 inFIG. 4 ) changes, a negative pressure is formed in theplunger chamber 39 corresponding to the plunger, and the fuel inlet and dischargevalve assembly 37 is closed in a commonly known manner to prevent backflow of the fuel from the common rail system. At the same time, the other plunger moves upwards as a lobe position of the other drive cam (e.g., thedrive cam 25 inFIG. 4 ) changes, a positive pressure is formed in theplunger chamber 39 corresponding to the plunger, and the fuel inlet and dischargevalve assembly 37 is opened in a commonly known manner so that the fuel is ejected from the fuel injection channel 43 and delivered to the common rail system. The process is performed alternately and repeatedly to continuously deliver the fuel to the common rail system. - Referring to
FIGS. 5 and 6 , which are respectively a partial cutaway perspective view and a sectional view of a tappet body according to an embodiment of the present application, wherein a roller is mounted in the tappet body. Thetappet body 15 is substantially cylindrical in shape and has a longitudinal central axis.First cavities 29 are formed on the side of each of thetappet bodies 15 that faces thedrive cams 25 and 27 (i.e., the bottom of each of the tappet bodies 15).Rollers 33 are held in thefirst cavities 29 bypin shafts 31 which are mounted on thetappet bodies 15 in such a way that the rollers are scrollable about thepin shafts 31 and axially movable along thepin shafts 31.Second cavities 30 are formed on the side of each of thetappet bodies 15 that is opposite thedrive cams 25 and 27 (i.e., the top of each of the tappet bodies 15).Central protrusions 16 are provided within thesecond cavities 30. Inner end faces 47 perpendicular to longitudinal central axes of thetappet bodies 15 are formed around thecentral protrusions 16, wherein at least one recess 38 (e.g., annular recess) is formed in theinner end face 47 in such a way that the recess surrounds thecentral protrusion 16 and is symmetrical about the longitudinal central axis of thetappet body 15. Of course, thetappet body 15 may also be not provided with thecentral protrusion 16 so that theinner end face 47 is a generally circular surface. - As shown in
FIG. 4 , aspring 35 and aspring seat 36 are further provided between theplunger sleeve 13 and thetappet body 15. Thespring seat 36 is accommodated within thesecond cavity 30, and one side of the spring seat 36 (i.e., an upper side) is in contact with thespring 35 and the other side (i.e., a lower side) is in contact with the inner end face 47 of thetappet body 15. Thespring 35 biases thetappet body 15 towards thecamshaft 17 by thespring seat 36 such that therollers 33 are always in contact with correspondingdrive cams camshaft 17 rotates, theplungers 11 move in a reciprocating manner up and down against outer contours of thedrive cams rollers 33 held on thetappet bodies 15 as contour positions of thedrive cams - When the
camshaft 17 rotates, thedrive cams tappet body 15 to move up and down, thereby driving theplunger 11 and theplunger sleeve 13 to move up and down. Since thespring 35 is located between thespring seat 36 and theplunger sleeve 13, thespring 35 is compressed and elongated repeatedly. In the process that thespring 35 is compressed and elongated, thespring 35 generates a torque due to inherent properties thereof, which accordingly drives thespring seat 36 to twist. As described above, the lower side of thespring seat 36 is in contact with the inner end face 47 of thetappet body 15. The torque generated by thespring 35 is transmitted to thetappet body 15 by means of friction between thespring seat 36 and thetappet body 15, driving thetappet body 15 to twist. However, since therecess 38 is provided in theinner end face 47, only part of the lower side of thespring seat 36 is in contact with theinner end face 47, rather than all of the lower side of thespring seat 36 is in contact with theinner end face 47. As a result, the contact area between thespring seat 36 and the inner end face 47 of thetappet body 15 is greatly reduced and thus the frictional force between them is reduced, which mitigates the friction between left and right side end faces of theroller 33 of thetappet body 15 and the inner end face of the tappet body. - In the above example, the
recess 38 is an annular recess and is configured such that at least part of the annular recess is at a position of theinner end face 47 proximate to an outer perimeter of theinner end face 47, i.e., the distance between the at least part of the annular recess and the longitudinal central axis of thetappet body 15 is greater than a half of the radius of theinner end face 47. This is because an annular contact part proximate to the outer perimeter of theinner end face 47 is often formed due to the contact between the lower side of thespring seat 36 and theinner end face 47. Hence, the contact area between the spring seat and the tappet body can be reduced provided that therecess 38 is disposed in the part of theinner end face 47 that is in contact with thespring seat 36. Furthermore, considering the moment caused by the frictional force, disposing therecess 38 at a position of theinner end face 47 that is proximate to the outer perimeter thereof can better reduce the torque transmitted to the tappet body. Preferably, the distance between the at least part of the annular recess and the longitudinal central axis of thetappet body 15 is greater than one third of the radius of theinner end face 47. - In another example, the
recess 38 can include a plurality of radial recesses or dispersedly-arranged recesses, and is configured such that at least part of the plurality of radial recesses or dispersedly-arranged recesses is at the position of theinner end face 47 that is proximate to the outer perimeter of theinner end face 47, i.e., the distance between the at least part of the plurality of radial recesses or dispersedly-arranged recesses and the longitudinal central axis of thetappet body 15 is greater than a half of the radius of theinner end face 47. Preferably, the distance is greater than one third of the radius of theinner end face 47. - Furthermore, it is noted that a solution in which the position of the recess can be accordingly adjusted depending on different contact positions between the spring seat and the inner end face of the tappet body is envisaged in the present application.
- As shown in
FIGS. 5 and 6 , thetappet body 15 can be further provided with at least two throughholes 48 for communication between thefirst cavity 29 and thesecond cavity 30, so as to maintain the pressure balance between the two cavities. In this example, the width of therecess 38 can be greater than the diameter of the throughhole 48 to reduce the contact area between the spring seat and the tappet body and to facilitate machining. A solution in which the width and depth of therecess 38 can be further adjusted according to the size of the tappet body and the spring seat is further envisaged in the present application, but is not described in further detail herein. - Therefore, by disposing the
recess 38 in the inner end face 47 of thetappet body 15, the contact area between the spring seat and the tappet body can be greatly reduced, thus greatly reducing the wear, which is caused by friction, of the left and right side end faces of the roller and the left and right inner side faces of the first cavity of the tappet body, and prolonging the service life of the tappet body and the roller held on same. - Although the particular embodiments of the present application have been described above, it will be understood by those skilled in the art that the embodiments are merely illustrative and the protection scope of the present application is defined by the appended claims. Those skilled in the art could make various changes or modifications to these embodiments without departing from the principle and essence of the present application, and all these changes and modifications shall fall within the protection scope of the present application.
Claims (9)
Applications Claiming Priority (2)
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CN201810755845.X | 2018-07-11 | ||
CN201810755845.XA CN110714866B (en) | 2018-07-11 | 2018-07-11 | Tappet body and fuel injection pump comprising same |
Publications (1)
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US20200018296A1 true US20200018296A1 (en) | 2020-01-16 |
Family
ID=69138764
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US16/505,882 Abandoned US20200018296A1 (en) | 2018-07-11 | 2019-07-09 | Tappet body and fuel injection pump comprising same |
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US (1) | US20200018296A1 (en) |
CN (1) | CN110714866B (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11131282B2 (en) * | 2019-03-01 | 2021-09-28 | Denso Corporation | Fuel injection pump |
WO2023117139A1 (en) * | 2021-12-21 | 2023-06-29 | Eaton Intelligent Power Limited | Pump actuator with improved fatigue life |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2004324537A (en) * | 2003-04-24 | 2004-11-18 | Bosch Automotive Systems Corp | Pump for fuel supply and tappet structure |
US7878169B2 (en) * | 2006-06-06 | 2011-02-01 | Woodward Governor Company | Cam roller pin with transverse grooves |
CN201092919Y (en) * | 2007-09-13 | 2008-07-30 | 成都市易控高科电喷有限责任公司 | Lubrication mechanism of stiff pole for fuel injection pump |
JP6380132B2 (en) * | 2015-01-29 | 2018-08-29 | 株式会社デンソー | Drive mechanism components |
EP3176421B1 (en) * | 2015-12-03 | 2018-07-04 | Aktiebolaget SKF | Cam follower roller device with reinforced tappet body |
-
2018
- 2018-07-11 CN CN201810755845.XA patent/CN110714866B/en active Active
-
2019
- 2019-07-09 US US16/505,882 patent/US20200018296A1/en not_active Abandoned
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11131282B2 (en) * | 2019-03-01 | 2021-09-28 | Denso Corporation | Fuel injection pump |
WO2023117139A1 (en) * | 2021-12-21 | 2023-06-29 | Eaton Intelligent Power Limited | Pump actuator with improved fatigue life |
Also Published As
Publication number | Publication date |
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CN110714866A (en) | 2020-01-21 |
CN110714866B (en) | 2023-04-28 |
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