WO2009103572A1 - High-pressure pump for feeding high-pressure fuel to an internal-combustion engine - Google Patents

High-pressure pump for feeding high-pressure fuel to an internal-combustion engine Download PDF

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Publication number
WO2009103572A1
WO2009103572A1 PCT/EP2009/050287 EP2009050287W WO2009103572A1 WO 2009103572 A1 WO2009103572 A1 WO 2009103572A1 EP 2009050287 W EP2009050287 W EP 2009050287W WO 2009103572 A1 WO2009103572 A1 WO 2009103572A1
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WO
WIPO (PCT)
Prior art keywords
hole
pump according
axis
wall
friction bearing
Prior art date
Application number
PCT/EP2009/050287
Other languages
French (fr)
Inventor
Johann Warga
Giuseppe Ficarella
Ruggiero Gissi
Original Assignee
Robert Bosch Gmbh
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Robert Bosch Gmbh filed Critical Robert Bosch Gmbh
Publication of WO2009103572A1 publication Critical patent/WO2009103572A1/en

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Classifications

    • 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
    • F02M59/04—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 special arrangement of cylinders with respect to piston-driving shaft, e.g. arranged parallel to that shaft or swash-plate type pumps
    • F02M59/06—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 special arrangement of cylinders with respect to piston-driving shaft, e.g. arranged parallel to that shaft or swash-plate type pumps with cylinders arranged radially to driving shaft, e.g. in V or star arrangement
    • 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
    • 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
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/02—Fuel-injection apparatus having several injectors fed by a common pumping element, or having several pumping elements feeding a common injector; Fuel-injection apparatus having provisions for cutting-out pumps, pumping elements, or injectors; Fuel-injection apparatus having provisions for variably interconnecting pumping elements and injectors alternatively
    • F02M63/0225—Fuel-injection apparatus having a common rail feeding several injectors ; Means for varying pressure in common rails; Pumps feeding common rails
    • F02M63/0265—Pumps feeding common rails
    • 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
    • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
    • F04B53/16—Casings; Cylinders; Cylinder liners or heads; Fluid connections
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C35/00—Rigid support of bearing units; Housings, e.g. caps, covers
    • F16C35/02—Rigid support of bearing units; Housings, e.g. caps, covers in the case of sliding-contact bearings

Definitions

  • the present invention relates to a high-pressure pump for feeding high-pressure fuel to an internal-combustion engine.
  • the present invention relates to a high-pressure pump comprising a pump body with a chamber designed to house a mechanism for actuating at least one pumping member, a wall provided with a hole along an axis and delimited by an inner surface arranged around the axis, a shaft rotating about the axis, and a friction bearing which is forced with an interference fit inside the hole of the wall and has the function of supporting the shaft rotating about the axis.
  • the friction bearing has a greater length than the hole of the friction bearing in the axial direction so as to allow at least one of the opposite ends of the friction bearing to be deformed resiliency when the shaft is subject to flexing moments along its axis so as to adapt to any misalignment of the shaft.
  • a high-pressure pump of the type identified above comprises three pumping members which are uniformly distributed about the shaft in respective radial directions and flexurally stress the shaft cyclically in the respective radial directions.
  • the object of the present invention is to provide a high-pressure pump which is devoid of the drawbacks of the prior art and which at the same time is low-cost and reliable.
  • a high-pressure pump for feeding high-pressure fuel to an internal-combustion engine
  • the high- pressure pump comprising a pump body with a chamber designed to house a mechanism for actuating at least one pumping member, a wall provided with a hole along an axis and delimited by an inner surface arranged around the axis, a shaft rotating about the axis, and a friction bearing which is forced with an interference fit inside the hole of the wall and has the function of supporting the shaft rotating about the axis
  • the high-pressure pump being characterized in that the friction bearing is completely contained inside the hole.
  • any anomalous or excessive flexing of the friction bearing is limited by the inner surface of the wall.
  • the friction bearing has an outer surface comprising an outer cylindrical surface in contact with the inner surface and two outer chamfers which are arranged on opposite sides of the outer cylindrical surface and define an angle with the inner surface.
  • the wall comprises at least one annular edge portion which extends around the hole and defines partly the said inner surface.
  • the annular edge portion has dimensions such that it may be resiliency deformable and is able to allow controlled deformation of the bearing and withstand any excessive forces transmitted by the flexurally stressed shaft.
  • the wall has two opposite faces and at least one groove arranged along one of the opposite faces and around the hole so as to define the annular edge portion.
  • FIG. 1 is a longitudinally sectioned view, with parts removed for greater clarity, of a high-pressure pump provided according to the present invention
  • FIG. 2 is a longitudinally sectioned view, with further parts removed for greater clarity and on a larger scale, of a detail of the high-pressure pump according to Figure 1;
  • FIG. 3 is a longitudinally sectioned view, with parts removed for greater clarity, of a further detail of a high-pressure pump according to the present invention.
  • FIG 1 denotes in its entirety a high-pressure pump designed to compress the fuel to pressures in the region of 2000 bar and supply fuel to a common rail and, then, to an internal-combustion engine (not shown in the accompanying figures).
  • the high-pressure pump 1 comprises a pump body 2, a chamber 3 designed to house an actuating mechanism (not shown in Figure 1), an actuating shaft 4 which is indicated by broken lines in Figure 1 and is rotatable about an axis A.
  • the actuating mechanism is designed to actuate at least one pumping member (also not shown in Figure 1) designed to move with a reciprocating movement in the radial direction relative to the shaft 4.
  • the pump body 2 comprises an annular wall 5 which has three seats 6 for housing respective pumping members (only two seats 6 are shown in Figure 1) and three service openings 7 (only two of which are shown in Figure 1) closed by respective plates 8 (only one of which is shown in Figure 1).
  • the seats 6 of the pumping members are arranged at 120° relative to each other about the axis A.
  • the pump body 2 comprises a wall 9 of considerable thickness which extends perpendicularly with respect to the axis A, is adjacent to the annular wall 5 and has a hole 10 along the axis A for housing the shaft 4.
  • the pump 1 comprises a flange 11 ( Figure 3) for closing the chamber 3, which is arranged on the opposite side to the wall 9, has the function of supporting the shaft 4 and is not shown in Figure 1.
  • the hole 10 is delimited by an inner surface 12 extending around the axis A, while the wall 9 comprises a face 13 perpendicular to the axis A and directed towards the chamber 3.
  • the high-pressure pump 1 comprises a friction bearing 14 which is formed by a steel bush lined internally with material having a low coefficient of friction, usually polymers with solid lubricating agglomerates, and has the function of supporting the shaft 4, in this case a portion of the shaft 4 provided with a ground outer surface 15.
  • the actuating mechanism in general comprises a cam fixed onto another portion of the shaft 4 inside the chamber 3.
  • the cam is designed to co-operate, in a known manner, with a prismatic ring of the known type (not shown in the accompanying figures) so as to actuate in sequence the three pumping members (not shown in the accompanying figures).
  • the friction bearing 14 comprises essentially a cylindrical wall having an outer surface 16 and an inner surface 17 rotatably coupled with the outer surface 15 of the portion of the shaft 4.
  • the friction bearing 14 is fixed with an interference fit inside the hole 10 and is completely contained inside the hole 10.
  • the inner surface 12 has a greater length, in the axial direction and on both sides, than the friction bearing 14.
  • the inner surface 12 comprises an inner cylindrical surface 18 and two inner chamfers 19A and 19B arranged on opposite sides of the inner cylindrical surface 18.
  • the outer surface 16 of the friction bearing 14 has an outer cylindrical surface 20 and two outer chamfers 21A and 21B arranged on opposite sides of the outer cylindrical surface 20.
  • the two outer chamfers 21A and 21B are defined by two respective frustoconical surfaces which form an acute angle with the inner surface 12 of the hole 10.
  • the wall 9 has an annular edge portion 22 which is arranged around the axis A and defines, partly, the inner surface 12.
  • the annular edge portion 22 forms an integral part of the wall 9 and is obtained by means of a groove 23 formed along the face 13 of the wall 9 itself.
  • the annular edge portion 22 has a thickness S in the radial direction and a length L in the axial direction, which ensure a certain degree of radial flexibility of the wall 9 in the region of the annular edge portion 22.
  • the groove 23 extends along an annular path around the hole 10, in particular the groove 23 extends along a circular path around the hole 10.
  • the groove 23 has a cross-section delimited by two parallel cylindrical faces 24 connected by a toroidal cavity 25.
  • Each groove 23 is arranged at a predefined distance from the inner cylindrical surface 18, equal to the thickness of the edge portion 22, in particular the thickness S of the edge portion 22 is less than one tenth of the diameter D of the hole 10.
  • the value of the thickness S of the edge portion 22 is a design parameter which, generally, depends on the materials, in particular the material from which the pump body 2 is made, the magnitude of the stresses transmitted by the shaft 4 to the friction bearing 14 and the pump body 2, and the diameter D of the hole 10.
  • the length L of the edge portion 22 is a design parameter which has a considerable importance in determining the flexibility of the edge portion 22 and depends on the abovementioned parameters.
  • the edge portion 22 extends from a wall 26 comprising a face 27 which is shown in broken lines in Figure 2.
  • the flange 11 comprises a wall 28 of considerable thickness which extends perpendicularly with respect to the axis A and has a hole 29 along the axis A for housing the shaft 4.
  • the high-pressure pump 1 comprises a friction bearing 32 which is formed by a steel bush lined internally with material having a low coefficient of friction, generally polymers with solid lubricating agglomerates, and has the function of supporting the shaft 4, in this case a portion of the shaft 4 provided with a ground outer surface 33.
  • the friction bearing 32 comprises essentially a cylindrical wall having an outer surface 34 and an inner surface 35 rotatably coupled with the outer surface 33 of the portion of the shaft 4.
  • the friction bearing 32 is fixed with an interference fit inside the hole 29 and is completely contained inside the hole 29.
  • the inner surface 30 has a greater length, in the axial direction and on both sides, than the friction bearing 32.
  • the inner surface 30 comprises an inner cylindrical surface 36 and two inner chamfers 37A and 37B arranged on opposite sides of the inner cylindrical surface 36.
  • the outer surface 34 of the friction bearing 32 has an outer cylindrical surface 38 and two outer chamfers 39A and 39B arranged on opposite sides of the outer cylindrical surface 38.
  • the two outer chamfers 39A and 39B are defined by two respective frustoconical surfaces which form an acute angle with the inner surface 30 of the hole 29, in particular with the inner cylindrical surface 36.
  • the wall 28 has respective annular edge portions 40 which are arranged around the axis A and define, partly, the inner surface 30.
  • the annular edge portions 40 form an integral part of the wall 28 and are obtained by means of respective grooves 41 formed along the opposite faces 31 of the wall 28 itself.
  • Each annular edge portion 40 has a thickness S in the radial direction and a length L in the axial direction, which ensure a certain degree of radial flexibility of the wall 28 in the region of the annular edge portions 40.
  • Each groove 41 extends along an annular path around the hole 29, in particular the groove 41 extends along a circular path around the hole 29.
  • Each groove 41 has a cross-section delimited by two parallel cylindrical faces 42 connected by a toroidal cavity 43.
  • the grooves 41 have a mirror symmetry relative to a plane P perpendicular to the axis A.

Abstract

A high-pressure pump (1) for feeding high-pressure fuel to an internal-combustion engine has a pump body (2) with a chamber (3) designed to house a mechanism for actuating at least one pumping member and a wall (9) provided with a hole (10) along an axis (A) and delimited by an inner surface (12) arranged around the axis (A), a shaft (4) rotating about the axis (A), a friction bearing (14) which is forced with an interference fit inside the hole (10) of the wall (9) of the pump body (2) and is completely contained inside the hole (10, 29).

Description

HIGH-PRESSURE PUMP FOR FEEDING HIGH-PRESSURE FUEL TO AN INTERNAL-COMBUSTION ENGINE
The present invention relates to a high-pressure pump for feeding high-pressure fuel to an internal-combustion engine.
In particular, the present invention relates to a high-pressure pump comprising a pump body with a chamber designed to house a mechanism for actuating at least one pumping member, a wall provided with a hole along an axis and delimited by an inner surface arranged around the axis, a shaft rotating about the axis, and a friction bearing which is forced with an interference fit inside the hole of the wall and has the function of supporting the shaft rotating about the axis.
Generally the friction bearing has a greater length than the hole of the friction bearing in the axial direction so as to allow at least one of the opposite ends of the friction bearing to be deformed resiliency when the shaft is subject to flexing moments along its axis so as to adapt to any misalignment of the shaft.
The structure of the high-pressure pump produces cyclical flexural stressing of the shaft which occurs in given directions. Generally, a high-pressure pump of the type identified above comprises three pumping members which are uniformly distributed about the shaft in respective radial directions and flexurally stress the shaft cyclically in the respective radial directions.
From a theoretical point of view, the constructional feature whereby the bearing has a greater length axially than the hole inside which it is force-fitted has proved to be particularly advantageous particularly owing to the capacity to adapt to the instantaneous configuration of the shaft. Unfortunately, from a practical point of view and considering the high number of flexural stresses affecting the shaft, and therefore the friction bearing, and the extremely high pressure values in the newly designed high-pressure pump, the risk of damage to the ends of the friction bearing and even breakage, due to fatigue, of the end of the bearing which has a greater length than the hole increases substantially in the newly designed pumps.
In particular, the increase in the magnitude of the stresses due to the increase in pressure would result in the need to design larger-size pumps in which the bearings would also have dimensions greater than the dimensions of the existing bearings. However, such a solution is not feasible for obvious cost-related reasons and because of the demands of manufacturers who require high- pressure pumps which are small in size.
The object of the present invention is to provide a high-pressure pump which is devoid of the drawbacks of the prior art and which at the same time is low-cost and reliable.
According to the present invention the object is achieved by a high-pressure pump for feeding high-pressure fuel to an internal-combustion engine, the high- pressure pump comprising a pump body with a chamber designed to house a mechanism for actuating at least one pumping member, a wall provided with a hole along an axis and delimited by an inner surface arranged around the axis, a shaft rotating about the axis, and a friction bearing which is forced with an interference fit inside the hole of the wall and has the function of supporting the shaft rotating about the axis, the high-pressure pump being characterized in that the friction bearing is completely contained inside the hole.
In accordance with the present invention, any anomalous or excessive flexing of the friction bearing is limited by the inner surface of the wall.
According to a particular embodiment of the present invention the friction bearing has an outer surface comprising an outer cylindrical surface in contact with the inner surface and two outer chamfers which are arranged on opposite sides of the outer cylindrical surface and define an angle with the inner surface.
In practice the chamfers allow slight deformations of the opposite ends of the friction bearing.
According to a particular embodiment of the present invention the wall comprises at least one annular edge portion which extends around the hole and defines partly the said inner surface.
The annular edge portion has dimensions such that it may be resiliency deformable and is able to allow controlled deformation of the bearing and withstand any excessive forces transmitted by the flexurally stressed shaft.
According to a particular advantageous embodiment of the present invention the wall has two opposite faces and at least one groove arranged along one of the opposite faces and around the hole so as to define the annular edge portion.
In this way by means of a simple chip-removal machining operation it is possible to form the annular edge portion in the wall.
Further details, characteristic features and advantages of the invention will emerge more clearly from the following description of non-limiting examples of embodiment, with reference to the accompanying figures in which:
- Figure 1 is a longitudinally sectioned view, with parts removed for greater clarity, of a high-pressure pump provided according to the present invention;
- Figure 2 is a longitudinally sectioned view, with further parts removed for greater clarity and on a larger scale, of a detail of the high-pressure pump according to Figure 1;
- Figure 3 is a longitudinally sectioned view, with parts removed for greater clarity, of a further detail of a high-pressure pump according to the present invention.
In Figure 1, 1 denotes in its entirety a high-pressure pump designed to compress the fuel to pressures in the region of 2000 bar and supply fuel to a common rail and, then, to an internal-combustion engine (not shown in the accompanying figures). The high-pressure pump 1 comprises a pump body 2, a chamber 3 designed to house an actuating mechanism (not shown in Figure 1), an actuating shaft 4 which is indicated by broken lines in Figure 1 and is rotatable about an axis A. The actuating mechanism is designed to actuate at least one pumping member (also not shown in Figure 1) designed to move with a reciprocating movement in the radial direction relative to the shaft 4.
In particular, the pump body 2 comprises an annular wall 5 which has three seats 6 for housing respective pumping members (only two seats 6 are shown in Figure 1) and three service openings 7 (only two of which are shown in Figure 1) closed by respective plates 8 (only one of which is shown in Figure 1). The seats 6 of the pumping members are arranged at 120° relative to each other about the axis A.
The pump body 2 comprises a wall 9 of considerable thickness which extends perpendicularly with respect to the axis A, is adjacent to the annular wall 5 and has a hole 10 along the axis A for housing the shaft 4. The pump 1 comprises a flange 11 (Figure 3) for closing the chamber 3, which is arranged on the opposite side to the wall 9, has the function of supporting the shaft 4 and is not shown in Figure 1.
In this case the hole 10 is delimited by an inner surface 12 extending around the axis A, while the wall 9 comprises a face 13 perpendicular to the axis A and directed towards the chamber 3.
The high-pressure pump 1 comprises a friction bearing 14 which is formed by a steel bush lined internally with material having a low coefficient of friction, usually polymers with solid lubricating agglomerates, and has the function of supporting the shaft 4, in this case a portion of the shaft 4 provided with a ground outer surface 15.
The actuating mechanism (not shown in the accompanying figures) in general comprises a cam fixed onto another portion of the shaft 4 inside the chamber 3. The cam is designed to co-operate, in a known manner, with a prismatic ring of the known type (not shown in the accompanying figures) so as to actuate in sequence the three pumping members (not shown in the accompanying figures).
The friction bearing 14 comprises essentially a cylindrical wall having an outer surface 16 and an inner surface 17 rotatably coupled with the outer surface 15 of the portion of the shaft 4.
The friction bearing 14 is fixed with an interference fit inside the hole 10 and is completely contained inside the hole 10. In the particular case shown in the accompanying figures, the inner surface 12 has a greater length, in the axial direction and on both sides, than the friction bearing 14.
In particular, the inner surface 12 comprises an inner cylindrical surface 18 and two inner chamfers 19A and 19B arranged on opposite sides of the inner cylindrical surface 18.
The outer surface 16 of the friction bearing 14 has an outer cylindrical surface 20 and two outer chamfers 21A and 21B arranged on opposite sides of the outer cylindrical surface 20. Basically the two outer chamfers 21A and 21B are defined by two respective frustoconical surfaces which form an acute angle with the inner surface 12 of the hole 10.
The wall 9 has an annular edge portion 22 which is arranged around the axis A and defines, partly, the inner surface 12. In the embodiment shown in the accompanying figures, the annular edge portion 22 forms an integral part of the wall 9 and is obtained by means of a groove 23 formed along the face 13 of the wall 9 itself.
The annular edge portion 22 has a thickness S in the radial direction and a length L in the axial direction, which ensure a certain degree of radial flexibility of the wall 9 in the region of the annular edge portion 22.
The groove 23 extends along an annular path around the hole 10, in particular the groove 23 extends along a circular path around the hole 10.
With reference to Figure 2, the groove 23 has a cross-section delimited by two parallel cylindrical faces 24 connected by a toroidal cavity 25.
Each groove 23 is arranged at a predefined distance from the inner cylindrical surface 18, equal to the thickness of the edge portion 22, in particular the thickness S of the edge portion 22 is less than one tenth of the diameter D of the hole 10.
The value of the thickness S of the edge portion 22 is a design parameter which, generally, depends on the materials, in particular the material from which the pump body 2 is made, the magnitude of the stresses transmitted by the shaft 4 to the friction bearing 14 and the pump body 2, and the diameter D of the hole 10.
In the same way, the length L of the edge portion 22 is a design parameter which has a considerable importance in determining the flexibility of the edge portion 22 and depends on the abovementioned parameters.
According to an alternative embodiment, the edge portion 22 extends from a wall 26 comprising a face 27 which is shown in broken lines in Figure 2.
With reference to Figure 3, the flange 11 comprises a wall 28 of considerable thickness which extends perpendicularly with respect to the axis A and has a hole 29 along the axis A for housing the shaft 4.
In this particular case, the hole 29 is delimited by an inner surface 30 extending around the axis A, while the wall 28 has two opposite faces 31 perpendicular to the axis A. The high-pressure pump 1 comprises a friction bearing 32 which is formed by a steel bush lined internally with material having a low coefficient of friction, generally polymers with solid lubricating agglomerates, and has the function of supporting the shaft 4, in this case a portion of the shaft 4 provided with a ground outer surface 33.
The friction bearing 32 comprises essentially a cylindrical wall having an outer surface 34 and an inner surface 35 rotatably coupled with the outer surface 33 of the portion of the shaft 4.
The friction bearing 32 is fixed with an interference fit inside the hole 29 and is completely contained inside the hole 29. In the particular case shown in the Figure 3, the inner surface 30 has a greater length, in the axial direction and on both sides, than the friction bearing 32.
In particular, the inner surface 30 comprises an inner cylindrical surface 36 and two inner chamfers 37A and 37B arranged on opposite sides of the inner cylindrical surface 36.
The outer surface 34 of the friction bearing 32 has an outer cylindrical surface 38 and two outer chamfers 39A and 39B arranged on opposite sides of the outer cylindrical surface 38. Basically the two outer chamfers 39A and 39B are defined by two respective frustoconical surfaces which form an acute angle with the inner surface 30 of the hole 29, in particular with the inner cylindrical surface 36.
The wall 28 has respective annular edge portions 40 which are arranged around the axis A and define, partly, the inner surface 30. In the embodiment shown in the accompanying figures, the annular edge portions 40 form an integral part of the wall 28 and are obtained by means of respective grooves 41 formed along the opposite faces 31 of the wall 28 itself.
Each annular edge portion 40 has a thickness S in the radial direction and a length L in the axial direction, which ensure a certain degree of radial flexibility of the wall 28 in the region of the annular edge portions 40. Each groove 41 extends along an annular path around the hole 29, in particular the groove 41 extends along a circular path around the hole 29.
Each groove 41 has a cross-section delimited by two parallel cylindrical faces 42 connected by a toroidal cavity 43.
The grooves 41 have a mirror symmetry relative to a plane P perpendicular to the axis A.
Finally, it is clear that the high-pressure pump described here may be subject to modifications and variations without departing from the scope of the accompanying claims.

Claims

Claims
1. High-pressure pump for feeding high-pressure fuel to an internal- combustion engine comprising a pump body (2) with a chamber (3) designed to house a mechanism for actuating at least one pumping member, a wall (9; 26; 28) provided with a hole (10; 29) along an axis (A) and delimited by an inner surface (12; 30) arranged around the axis (A), a shaft (4) rotating about the axis (A), and a friction bearing (14; 32) which is forced with an interference fit inside the hole (10; 29) of the wall (9; 26; 28) and has the function of supporting the shaft (4) rotating about the axis (A), the high-pressure pump being characterized in that the friction bearing (14; 32) is completely contained inside the hole (10;
29).
2. Pump according to Claim 1, characterized in that the inner surface (12; 30) has a greater length, in the axial direction and on both sides, than the friction bearing (14; 32).
3. Pump according to Claim 1 or 2, characterized in that the inner surface (12; 30) comprises an inner cylindrical surface (18; 36), the inner cylindrical surface (36) having a greater length, in the axial direction and on both sides, than the friction bearing (32).
4. Pump according to any one of Claims 1 to 3, characterized in that the friction bearing (14; 32) has an outer surface (16; 34) comprising an outer cylindrical surface (20; 38) in contact with the inner surface (12; 30) and two outer chamfers (19A, 19B; 37A, 37B) which are arranged on opposite sides of the outer cylindrical surface (20; 38) and form respective angles with the inner surface (12; 30).
5. Pump according to Claim 4, characterized in that the said angles are acute angles.
6. Pump according to any one of the preceding claims, characterized in the wall (9; 26; 28) comprises at least one annular edge portion (22; 40) which extends around the hole (10; 29) and defines, partly, the said inner surface (12;
30).
7. Pump according to Claim 6, characterized in that the wall (9; 28) has two opposite faces (13) and at least one groove (23; 41) which is arranged along a face (13; 31) and around the hole (10; 29) so as to define the annular edge portion (22; 40).
8. Pump according to Claim 7, characterized in that the groove (23; 41) extends along an annular path around the hole (10; 29).
9. Pump according to Claim 8, characterized in that the groove (23; 41) extends along a circular path around the hole (10; 29).
10. Pump according to any one of Claims 7 to 9, characterized in that it comprises two grooves (43) which are formed in the wall (28) respectively along the opposite faces (31) and have a mirror symmetry relative to a plane (P) perpendicular to the axis (A).
11. Pump according to any one of Claims 7 to 10, characterized in that each groove (23; 41) has a cross-section delimited by two parallel cylindrical faces (24;
42) connected by a toroidal cavity (25; 43).
12. Pump according to any one of Claims and 6 to 11, characterized in each annular edge portion (22) has a predefined thickness (S) in the radial direction.
13. Pump according to Claim 12, characterized in that the said thickness (S) is less than one tenth of the diameter (D) of the hole (9).
14. Pump according to any one of Claims 6 to 12, characterized in each annular edge portion (22; 40) has a predefined length (L) in the axial direction with respect to the axis (A).
PCT/EP2009/050287 2008-02-22 2009-01-13 High-pressure pump for feeding high-pressure fuel to an internal-combustion engine WO2009103572A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITMI2008A000288 2008-02-22
ITMI20080288 ITMI20080288A1 (en) 2008-02-22 2008-02-22 HIGH PRESSURE PUMP FOR HIGH PRESSURE FUEL SUPPLY TO AN INTERNAL COMBUSTION ENGINE

Publications (1)

Publication Number Publication Date
WO2009103572A1 true WO2009103572A1 (en) 2009-08-27

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ID=40291688

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2009/050287 WO2009103572A1 (en) 2008-02-22 2009-01-13 High-pressure pump for feeding high-pressure fuel to an internal-combustion engine

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WO (1) WO2009103572A1 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2018272131B2 (en) * 2017-05-23 2023-12-14 Societe Des Produits Nestle S.A. Beverage preparation machine with enhanced pump control

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19814505A1 (en) * 1997-07-11 1999-01-21 Bosch Gmbh Robert Radial piston pump for a motor fuel injection system
EP1306553A2 (en) * 2001-10-27 2003-05-02 Robert Bosch Gmbh Fuel pump, fuel system and method for operating a fuel system and an internal combustion engine
WO2004003385A1 (en) * 2002-06-26 2004-01-08 Siemens Aktiengesellschaft Radial piston pump
DE10305011A1 (en) * 2003-02-07 2004-08-19 Robert Bosch Gmbh High-pressure pump for an internal combustion engine's fuel injection device has a drive shaft to rotate on bearings in a casing
WO2005057004A1 (en) * 2003-12-10 2005-06-23 Robert Bosch Gmbh Valve arrangement in particular inlet valve for a high pressure fuel pump
DE102005046670A1 (en) * 2005-09-29 2007-04-05 Robert Bosch Gmbh High pressure pump for fuel injection device of internal combustion engine, has ball indirectly fixed in part of base plate in tangential direction to tappet and engaged in groove approximately radial to longitudinal axis of tappet
DE102006051332A1 (en) * 2006-10-31 2008-05-08 Robert Bosch Gmbh Feed pump, in particular for the promotion of diesel fuel with improved storage of the drive shaft
DE102007029965A1 (en) * 2007-06-28 2009-01-08 Robert Bosch Gmbh High pressure fuel pump arrangement, has pump housing for operating compression-ignition internal combustion engine, low-pressure circuit and high-pressure circuit

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19814505A1 (en) * 1997-07-11 1999-01-21 Bosch Gmbh Robert Radial piston pump for a motor fuel injection system
EP1306553A2 (en) * 2001-10-27 2003-05-02 Robert Bosch Gmbh Fuel pump, fuel system and method for operating a fuel system and an internal combustion engine
WO2004003385A1 (en) * 2002-06-26 2004-01-08 Siemens Aktiengesellschaft Radial piston pump
DE10305011A1 (en) * 2003-02-07 2004-08-19 Robert Bosch Gmbh High-pressure pump for an internal combustion engine's fuel injection device has a drive shaft to rotate on bearings in a casing
WO2005057004A1 (en) * 2003-12-10 2005-06-23 Robert Bosch Gmbh Valve arrangement in particular inlet valve for a high pressure fuel pump
DE102005046670A1 (en) * 2005-09-29 2007-04-05 Robert Bosch Gmbh High pressure pump for fuel injection device of internal combustion engine, has ball indirectly fixed in part of base plate in tangential direction to tappet and engaged in groove approximately radial to longitudinal axis of tappet
DE102006051332A1 (en) * 2006-10-31 2008-05-08 Robert Bosch Gmbh Feed pump, in particular for the promotion of diesel fuel with improved storage of the drive shaft
WO2008052842A1 (en) * 2006-10-31 2008-05-08 Robert Bosch Gmbh Delivery pump, in particular for delivering diesel fuel, having improved mounting of the drive shaft
DE102007029965A1 (en) * 2007-06-28 2009-01-08 Robert Bosch Gmbh High pressure fuel pump arrangement, has pump housing for operating compression-ignition internal combustion engine, low-pressure circuit and high-pressure circuit

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