GB2551203A

GB2551203A - Guiding arangement of high pressure pump

Info

Publication number: GB2551203A
Application number: GB1610181.8A
Authority: GB
Inventors: Playle Andrew
Original assignee: Delphi International Operations Luxembourg SARL
Current assignee: Delphi International Operations Luxembourg SARL
Priority date: 2016-06-10
Filing date: 2016-06-10
Publication date: 2017-12-13
Anticipated expiration: 2036-06-10
Also published as: EP3469214B1; EP3469214A1; WO2017211480A1; GB201610181D0; GB2551203B

Abstract

A shoe guide member 30 of a high pressure fuel pump is provided with a guiding bore 56 opening in a top face 52 and in a bottom face 54 of the shoe guide member. The guiding bore 56 defines guiding faces 58, 60, 62 & 64 against which, in use, slide faces of a shoe member. The shoe guide member is further provided with at least one groove 66 arranged in a guiding face, said groove extending from said top to said bottom face and enabling, in use, lubricant fluid to flow between said top and bottom faces. A plurality of grooves may be used on all faces of the shoe guide, the grooves may be equally spaced and parallel to each other. Grooves may be employed on the shoe, rather than the shoe guide, or on both members simultaneously.

Description

GUIDING ARRANGEMENT OF HIGH PRESSURE PUMP

TECHNICAL FIELD

The present invention relates to a high pressure pump and more particularly to a guiding arrangement adapted to guide a shoe member and roller cooperating with a cam.

BACKGROUND OF THE INVENTION

In high pressure fuel pump, a piston reciprocally translates within a bore performing therein a pumping cycle. A rotating cam cooperates with the piston via a cam follower provided at an end of the piston. The cam follower comprises a shoe and a cylindrical roller, the shoe being a parallelepiped rectangle provided, on a lower side with a cylindrical hollow wherein is complementary received the roller and, on the opposite upper side with an abutment face for the lower end of the piston. The displacement of the shoe are guided in a shoe guide fixed in the body of the pump, said shoe guide being provided with a complementary opening having a rectangular section and defining long and short faces against which, in use, the shoe member slides.

Despite a flow of lubricant fluid within a thin functional clearance defined between the shoe member and the shoe guide, wear due to cavitation of the fluid is observed on the sliding faces.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to resolve the above mentioned problems in providing a shoeguide member of a high pressure fuel pump, the shoe guide member being provided with a guiding bore opening in a top face and in a bottom face of the shoe guide member, said guiding bore defining guiding faces, against which, in use, slide faces of a shoe member.

The shoe guide member is further provided with at least one groove arranged in a guiding face, said groove extending from said top to said bottom face and enabling, in use, lubricant fluid to flow between said top and bottom faces.

Also, the guiding bore has two long faces parallel to each other and two short faces parallel to each other, the short faces being perpendicular to the long faces and wherein, each of the long face is provided with at least one groove.

Also, the shoe guide member further comprises a plurality of said grooves in each of the lateral guiding face.

Also, the guiding bore defines a pumping axis, the groove being aligned with said pumping axis.

Also, said plurality of grooves are parallel to each other.

Also, said plurality of grooves are equally distributed across said guiding faces.

Also, said groove intersects with said guiding face along edge lines which are rounded and smooth so that, stress concentration are avoided.

The invention further extends to a shoe member adapted to be slidably guided within a guiding bore provided in a shoe guide member, the shoe member having side faces sliding, in use, against guiding faces of the guiding bore and, the shoe member is further provided with at least one groove arranged in a side face, said groove extending from a top face to a bottom face of the shoe member and enabling, in use, lubricant fluid to flow between said top and bottom faces.

Also, the shoe member has two lateral faces, parallel to each other and two end faces, parallel to each other, the end faces, being perpendicular to the lateral faces, and wherein, each of the lateral face, is provided with at least one groove.

Also, the shoe member further comprises a plurality of said grooves in each of the lateral face,. also, in use, the shoe member slides along a pumping axis, the groove being aligned with said pumping axis.

Also, said plurality of grooves are parallel to each other.

Also, said plurality of grooves are equally distributed across said side faces.

Also, said groove intersects with said lateral face along edge lines which are rounded and smooth so that, stress concentration are avoided.

The invention further extends to a guiding arrangement of a shoe member slidably arranged in a shoe guide member as previously described.

The invention further extends to high pressure fuel pump comprising a shoe member or a shoe guide member or a guiding arrangement as previously described.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is now described by way of example with reference to the accompanying drawings in which:

Figure 1 is a section of a high pressure pump provided with a shoe guide member as per the invention.

Figure 2 is a magnified area of the pump of figure 1.

Figure 3 is a 3D view of the shoe guide member of the pump of figure 1. Figure 4 is a top view of the shoe guide member of figure 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In reference to the figures is now described a high pressure diesel pump 10 adapted to be arranged in a diesel fuel injection equipment between an upstream low pressure delivery unit and a high pressure injection unit. The pump 10 comprises a pump body 12 on which is fixed a pumping head 14 wherein a piston 16, slidably arranged in a bore 18 extending along a pumping axis X, performs a pumping cycle during which the volume of a control chamber 20 is varied.

The pump body 12 further defines an inner space S wherein is arranged a camshaft 22 adapted to rotate about a camshaft axis Y1 perpendicular to the pumping axis X.

While the upper end of the piston remains inside the pumping head 14 and directly contributes to the compression of the fuel in the compression chamber, an opposite lower end 24 of the piston protrudes outside the pumping head 14, and extends inside the inner space S for cooperating via a cam-follower 26 with a cam 28 of the camshaft 22. The cam-follower 26 is fixed to said lower end 24 and is axially guided along the pumping axis X by a guide member 30 fixed to the pump body 12.

In use, the cam 28 rotates about the camshaft axis Y1 and it urges the piston 16, via the cam-follower 26, to said reciprocal displacements forming the pumping cycle.

The use of relative terms such as upper or lower is done in relation to the arbitrary orientation of figure 1. It eases and clarifies the description and must not be interpreted as a limitation to the invention.

More precisely, the cam-follower 26 comprises a shoe member 32 wherein is received a cylindrical roller 34 adapted to rotate about a roller axis Y2 parallel to the camshaft axis Yl. In use, the outer cylindrical face of the roller rolls on the cam profile and imparts said axial X displacements to the shoe member 32 and to the piston 16.

In a plan transverse to the pumping axis X, the shoe member 32 has a rectangular cross-section and its shape is substantially circumscribed to a parallelepiped rectangle. The shoe member 32 has a rectangular flat upper face 36 receiving in abutment the lower end 24 of the piston and, an opposed lower face 38 provided with a cylindrical concave hollow 40 adjusted to complementary receive the roller 34. Between said upper 36 and lower 38 faces are defined four side faces comprising two lateral faces 42, 44, parallel to each other, said lateral faces being rectangular, and two end faces 46, 48 parallel to each other and transverse to the roller axis Y2, the hollow 40 opening in a truncated circle in said end faces.

The cam-follower 26 is axially X guided within the guide member 30, or shoe guide member 30 represented on figures 3 and 4.

The shoe guide member 30 is a tubular member having a cylindrical lateral face 50 extending along the pumping axis X between a transverse top face 52 and an opposed transverse bottom face 54. Alternatively, other profiles such as rectangular are possible for the lateral face 50. The shoe guide 30 further defines a guiding bore 56 opening in said top 52 and bottom 54 faces, said guiding bore 56 defining four guiding faces 58, 60, 62, 64, comprising a first 58 and a second 60 long faces that are parallel to each other and, a first 62 and a second 64 short faces that are parallel to each other, the short faces 62, 64, being perpendicular to the long faces.

The guiding bore 56 is adapted to complementary receive the shoe member 32, the lateral faces 42, 44, of the shoe member sliding against the long faces 58, 60 of the bore 56 and, the end faces 46, 48, of the shoe member sliding against the short faces 62, 64, of the bore. To enable the relative sliding movements, a functional clearance C is defined between each pair of sliding faces.

In a first embodiment of the invention, as represented of figure 3, the long faces 58, 60 of the bore 56 are provided with vertical grooves 66 extending along the pumping axis X between the top 52 and bottom face 54 of the shoe guide member. In the figure five grooves 66 are represented but any other number is possible. Also, only one of the long face is visible but the grooves 66 are provided on both long faces 58 and 60.

The grooves 66 represented have a triangular profile but other profiles, semi-circular, square, trapezoidal... are adequate as well. The grooves 66 intersect with the long faces 58, 60 along edge lines 68 and, to avoid stress concentration, said edge lines 68 are rounded to provide a smooth transition between the face and the groove.

Conclusive tests have been performed demonstrating that said grooves 66 ease the lubricant flow and avoid wear due to cavitation of said lubricant fluid.

In a non-represented alternative, the first and second short faces 62, 64, of the shoe guide member 30 are also provided with grooves 66.

In a non-represented second embodiment, the faces of the guiding bore 56 are planar and the side faces 42, 44, of the shoe member are provided with grooves 66 having rounded edge lines 68.

In an alternative to said second embodiment, the end faces 46, 48, of the shoe member are also provided with grooves 66.

In a third embodiment, combining the first and second embodiments as well as their alternatives, faces of both the shoe member 32 and of the shoe guide member 30 are provided with grooves 66.

LIST OF REFERENCES X pumping axis Y1 camshaft axis Y2 roller axis S inner space C clearance 10 pump 12 pump body 14 pumping head 16 piston 18 bore 20 control chamber 22 camshaft 24 lower end of the piston 26 cam-follower 28 cam 30 shoe guide member 32 shoe member 34 roller 36 upper face of the shoe member 38 lower face of the shoe member 40 concave hollow 42 side face of the shoe member - lateral face 44 side face of the shoe member - lateral face 46 side face of the shoe member - end face 48 side face of the shoe member - end face 50 outer face of the shoe guide member 52 top face of the shoe guide member 54 bottom face of the shoe guide member 56 guiding bore 58 guiding face of the guiding bore - first long face 60 guiding face of the guiding bore - second long face 62 guiding face of the guiding bore - first short face 64 guiding face of the guiding bore - second short face 66 groove 68 edge lines of the groove

Claims

CLAIMS:

1. Shoe guide member (30) of a high pressure fuel pump (10), the shoe guide member (30) being provided with a guiding bore (56) opening in a top face (52) and in a bottom face (54) of the shoe guide member, said guiding bore (56) defining guiding faces (58, 60, 62, 64) against which, in use, slide faces (42, 44, 46, 48) of a shoe member, characterized in that the shoe guide member (30) is further provided with at least one groove (66) arranged in a guiding face (58, 60, 62, 64), said groove (66) extending from said top (52) to said bottom (54) face and enabling, in use, lubricant fluid to flow between said top and bottom faces.

2. Shoe guide member (30) as claimed in the preceding claim wherein the guiding bore (56) has two long faces (58, 60) parallel to each other and two short faces (62, 64) parallel to each other, the short faces (62, 64) being perpendicular to the long faces (58, 60) and wherein, each of the long face (58, 60) is provided with at least one groove (66).

3. Shoe guide member (30) as claimed in claim 2 further comprising a plurality of said grooves (66) in each of the lateral guiding face.

4. Shoe guide member (30) as claimed in any one of the preceding claims wherein the guiding bore (56) defines a pumping axis (X), the groove (66) being aligned with said pumping axis (X).

5. Shoe guide member (30) as claimed in claim 4 when depending upon claim 3 wherein said plurality of grooves (66) are parallel to each other.

6. Shoe guide member (30) as claimed in claim 5 wherein said plurality of grooves (66) are equally distributed across said guiding faces.

7. Shoe guide member (30) as claimed in any one of the preceding claims wherein said groove (66) intersects with said guiding face along edge lines (68) which are rounded and smooth so that, stress concentration are avoided.

8. Shoe member (32) of a high pressure fuel pump (10), the shoe member (32) being adapted to be slidably guided within a guiding bore (56) provided in a shoe guide member (30), the shoe member (32) having side faces (42,44,46,48) sliding, in use, against guiding faces (58, 60, 62, 64) of the guiding bore (56), characterized in that the shoe member (32) is further provided with at least one groove (66) arranged in a side face (42,44,46,48), said groove (66) extending from a top face (36) to a bottom face (38) of the shoe member and enabling, in use, lubricant fluid to flow between said top and bottom faces.

9. Shoe member (32) as claimed in claim 8 wherein the shoe member (32) has two lateral faces (42, 44) parallel to each other and two end faces (46, 48) parallel to each other, the end faces (46, 48) being perpendicular to the lateral faces (42, 44) and wherein, each of the lateral face (42, 44) is provided with at least one groove (66).

10. Shoe member (32) as claimed in claim 9 further comprising a plurality of said grooves (66) in each of the lateral face (42, 44).

11. Shoe member (32) as claimed in any one of the claims 8 to 10 wherein, in use, the shoe member (32) slides along a pumping axis (X), the groove (66) being aligned with said pumping axis (X).

12. Shoe member (32) as claimed in claim 11 when depending upon claim 10 wherein said plurality of grooves (66) are parallel to each other.

13. Shoe member (32) as claimed in claim 12 wherein said plurality of grooves (66) are equally distributed across said side faces.

14. Shoe member (32) as claimed in any one of the claims 8 to 13 wherein said groove (66) intersects with said lateral face along edge lines (68) which are rounded and smooth so that, stress concentration are avoided.

15. Guiding arrangement of a shoe member (32) as claimed in any one of the claims 8 to 14 slidably arranged in a shoe guide member (30) as claimed in any one of the claims 1 to 7.

16. High pressure fuel pump (10) comprising a shoe member (32) as claimed in any one of the claims 8 to 14, or a shoe guide member (30) as claimed in any one of the claims 1 to 7 or a guiding arrangement as claimed in claim 15.