EP2915994A1

EP2915994A1 - Tappet arrangement and pump

Info

Publication number: EP2915994A1
Application number: EP14158131.4A
Authority: EP
Inventors: Cristian Adrian Rosu
Original assignee: Continental Automotive GmbH
Current assignee: Continental Automotive GmbH
Priority date: 2014-03-06
Filing date: 2014-03-06
Publication date: 2015-09-09
Also published as: WO2015132052A1

Abstract

A tappet arrangement (200) for a high pressure pump comprises a tappet body (201), a roller (202) arranged partly in the tappet body, and a fixing (203) for holding the roller (202) in the tappet body to prevent a movement of the roller (202) in direction of the longitudinal axis (R) of the roller. The tappet body comprises a first (2041) and a second (2042) side surface arranged opposite to each other, and aligned in direction of the longitudinal axis of the roller, and a third (2051) and a fourth (2052) side surface arranged opposite to each other, and aligned perpendicular to the direction of the longitudinal axis of the roller, wherein the dimension of the first and the second side surfaces in direction of the longitudinal axis of the roller is larger than the dimension of the third and the fourth side surfaces perpendicular to the direction of the longitudinal axis of the roller.

Description

The invention relates to a tappet arrangement for a high-pressure pump for the delivery of a fluid and a pump.
In today's automotive engine systems, there is an increased demand for low cost, direct injection. In common rail injection systems, the fuel is delivered by means of a high pressure pump from a fuel tank to a fuel rail which serves as a storage reservoir for the fuel. The fuel is under high pressure in the fuel rail (or common rail) and can be injected directly into the cylinders via injection valves connected to the rail.
Two of the main concerns related to the common rail pumps are cost and durability. On one hand, high durability is required and higher pressure energy output for the pump and on the other hand, the pump has to become smaller to fit to the downsizing strategy of the engine market. These requirements can be in contradiction as downsizing may lead to a reduction of the space available to design a robust pump. In these circumstances, the pump design is pushed towards selecting expensive materials and creating expensive features to ease the internal stresses.
It is desirable to provide a tappet arrangement for a high-pressure pump and a pump which is cost effective and reliable.
According to an aspect of the invention, a tappet arrangement for a high-pressure pump comprises a tappet body. The tappet arrangement comprises a roller partly arranged in the tappet body. The tappet arrangement further comprises a fixing for holding the roller and the tappet body to prevent a movement of the roller in the direction of the longitudinal axis of the roller. The tappet body comprises a first and a second side surface arranged opposite to each other, and aligned in direction of the longitudinal axis of the roller. Furthermore, the tappet body comprises a third and a fourth side surface arranged opposite to each other, and aligned perpendicular to the direction of the longitudinal axis of the roller, wherein the dimension of the first and the second side surfaces in direction of the longitudinal axis of the roller is larger than the dimension of the third and the fourth side surfaces perpendicular to the direction of the longitudinal axis of the roller. By forming the tappet body such that the dimension of the first and second side surfaces are larger than the dimension of the third and fourth side surfaces an elongated body is formed. When such an elongated body is guided in a correspondingly formed bore of a pump housing a rotation of this body in the bore is prevented, thus reducing the stress to the components of the tappet arrangement.
According to a development of the invention the tappet body is curved or radiused on the first and second side surfaces, in particular representing two outside vertical sides of the tappet body along the roller for movable coupling the tappet arrangement with a pump housing of the high pressure pump. Therefore, although the tapped body is basically prevented from rotating because of its elongated shape guided in the correspondingly formed bore of a pump housing, the tappet arrangement is able to slightly rotate in its bore in the pump housing due to the first and second curved side surfaces. Thus, the tappet arrangement is able to self-align about its longitudinal axis, for example when the bore is not perfectly aligned with the position of a cam of a driveshaft of the pump. Further, a misalignment coming from the position and clearance of the bearings where the camshaft sits is compensated. In this context it is possible that the first and the second side surfaces are curved convex with respect to the tappet body. In particular it is possible that the peak of the curvature of the first side surface is displaced to the peak of the curvature of the second side surface in direction of the longitudinal axis of the roller. Consequently, by forming the corresponding bore of the pump housing in the same geometry, a clearance between the tappet body and the walls surrounding the bore will allow the tappet body to rotate for a very limited number of degrees, without spinning around its vertical axis. Thus, the roller alignment with the cam is improved.
According to a further development, the tappet body comprises two flat side surfaces, i.e. the third and fourth side surfaces, arranged opposite to each other aligned in the direction across the longitudinal axis of the roller. The two flat faces of the tappet arrangement are straight to limit the rotation of the tappet arrangement. In particular the third and fourth side surfaces are adjacent to the first and second side surfaces (in other words, they are connecting first and second side surfaces).
According to a further development, the fixing comprises two projecting parts that each are in contact with the roller to prevent a movement of the roller in the direction of the longitudinal axis of the roller. The fixing comprises two contact points with the roller. The fixing is designed to fit in position with the roller center to reduce the braking torque of the roller. For example, the fixing comprises a tip at each of the two projecting parts that is in contact with the roller. In this context it is also possible that each of the projecting parts has a spherical segment that is in contact with the roller center at the longitudinal axis to prevent the movement of the roller in direction of the longitudinal axis of the roller. The basic idea to contact the roller at the roller center is that at the center (where the longitudinal or rotational axis goes through) the theoretical speed of the roller is zero. Thus, by contacting the roller center there is provided axial constraint to the roller without introducing a braking torque.
According to a further development, the fixing is made from a metallic material with elastic properties, for example brass. The fixing can be a part separate to the tappet body, and can be formed as a clip or bracket. In particular the fixing is tightly connected to the tappet body by a force fit or tight fit.
For the connection to the tappet body each of the projecting parts of the fixing can have a protrusion sticking out of the projecting part for contacting the tappet body in order to secure the fixing to the tappet body.
According to a further development, the fixing can have a base element connecting the projecting parts. When assembling, the base element can be fixed on a site of the tappet body opposite the roller. Furthermore, the base element can have a recess for coupling the tappet arrangement with a plunger of the high pressure pump.
It is possible to arrange the protrusion on the base element near side of one projecting part, and to arrange the spherical segment on the base element distant side of one projecting part.
According to a further development, each of the projecting parts has a tapering section, in particular a trapezoidal section. Furthermore, it is possible that the base element merges into the tapering section of each projecting part. By providing a projecting part of the fixing with a large dimension or diameter adjacent to the base element a reliable strength against fatigue bending due to axial force from the roller is given. Moreover, the protrusion can be located at an area of the projecting having a large dimension or diameter for a robust fit on the tappet body, and the spherical segment can be located at an area of the projecting having a small dimension or diameter.
According to an aspect of the invention, a high-pressure pump for use in an internal combustion engine comprises a plunger for pressurizing fuel within a pump chamber of a pump housing during a plunger pumping stroke. The pump comprises a driveshaft and the tappet arrangement as described above. The tappet arrangement is coupled with the plunger and the driveshaft for imparting drive from the driveshaft to the plunger to perform the plunger pumping stroke.
According to further aspects, the pump housing comprises a bore. The shape of a wall surrounding the bore corresponds with the shape of the first and second curved side surfaces and the first and second curved side surfaces each are in contact with the wall of the bore. Therefore, the tappet arrangement is able to slightly rotate with respect to the pump housing and to self-align with respect to the pump housing and the driveshaft.
According to further aspects, the wall surrounds the bore such that the third and fourth flat side surfaces are arranged at a distance from the wall. Thus, the rotation of the tappet arrangement with respect to the pump housing is limited to a given angle.
The tappet arrangement and the bore correspond to each other with a clearance given to provide the required maximum rotation degree of the tappet arrangement with respect to the pump housing. The corners between the two curved side surfaces and the two flat side surfaces serve as rotation stops for the tappet arrangement. The corners are free to travel on a circle circumscribed to the radiused edges for only the amount of space allowed by the clearance between the two flat side surfaces and the corresponding wall of the bore. Thus, the robustness of the pump is increased by the mean of the increase in robustness for the roller alignment to the cam of the driveshaft.
According to a further development, the wall surrounding the bore, in particular that part of the wall being in contact with the first and second curved side surfaces of the tappet body is covered by a abrasion protective coating. Thus, for additional robustness the wall can be covered with a polymeric coating like PEEK or PTFE and their derivates, or can be heat treated with known methods such as anodising.
Reference will now be made in detail to the preferred embodiments, examples of which are illustrated in the accompanying drawings. The same elements, elements of the same type and elements having the same effect may be provided with the same reference symbols in the figures.

FIG. 1: schematically shows a tappet arrangement according to an embodiment; and
FIG. 2: schematically shows a detail of a high-pressure pump according to an embodiment;
FIGS. 3: schematically show a tappet arrangement according to a second embodiment, wherein FIG. 3A shows a perspective view from a front, side and top perspective, and wherein FIG. 3B shows a front view;
FIGS. 4: schematically show the fixing of the tappet arrangement according to the second embodiment, wherein FIG. 4A shows a front view, and FIG. 4B shows a side view;
FIG. 5: schematically shows a top view of the tappet body of the tappet arrangement according to the second embodiment;
FIG. 6: schematically shows a detail of a high-pressure pump with the tappet arrangement according to the second embodiment;
FIG. 7: schematically shows a cross-sectional view of the tappet body in the bore of the pump housing along the plane A-A in FIG. 6.

A tappet arrangement 100 comprises a tappet body 101 and a roller 102. The roller is coupled with the tappet body 101 by a fixing 103.
The roller is coupled with the tappet body 101 such that the roller is able to rotate relative to the tappet body 101 about its longitudinal axis R. The fixing 103 comprises two projecting parts 106. Each of the projecting parts 106 is coupled with a plane of the cylinder-shaped roller 102. For example, each of the projecting parts 106 comprises a point at the end that is in contact with the roller 102. The tip is in contact with the roller 102 in the roller center at the longitudinal axis R. Thus, the friction and the braking torque between the roller 102 and the fixing 103 is reduced. For example, the fixing 103 is made from a metallic material with elastic properties, for example brass or other metallics. The fixing 103 is a separate part to the tappet body 101 and, for example, is clipped on the tappet body 101. The tappet body 101 comprises two curved side surfaces 104. The curved side surfaces 104 are positioned opposite each other. The curved side surfaces are convex. The two curved side surfaces 104 are aligned in the direction of the longitudinal axis R of the roller 102 and in the direction of the longitudinal axis L of the tappet body.
The tappet body 101 further comprises two flat side surfaces 105 that are aligned in the direction across the longitudinal axis R of the roller 102 and in the direction of the longitudinal axis L of the tappet body 101. The two flat side surfaces 105 each are in alignment with the two planes of the roller 102. The two projecting parts 106 of the fixing 103 are arranged at the respective flat side surfaces 105. The two projecting parts 106 prevent the roller 102 from moving along its longitudinal axis R between the two flat side surfaces 105. The roller 102 is able to rotate about its longitudinal axis R with respect to the tappet body 101 as well as the fixing 103 and is restrained from moving in the direction of the longitudinal axis R of the roller 102 and the longitudinal axis L of the tappet body 101.
According to aspects, the tappet body 101 comprises a recess 107 on a side 115 opposite the roller 102. The recess is provided for coupling the tappet arrangement 100 with a plunger 110 (FIG. 2) of the high-pressure pump. The fixing 103 comprises a corresponding opening 108 such that the plunger 110 can reach through the fixing 103 into the recess 107.
FIG. 2 schematically shows a detail of a pump according to an aspect. The pump comprises a housing 114 that surrounds a bore 112. The bore 112 is surrounded by a wall 113. The plunger 110 is mounted within the bore 112. A driveshaft 111 is arranged. The driveshaft 111 comprises an engine-driven cam. As the cam is driven in use, the plunger 110 is caused to reciprocate within the bore 112 and causes pressurization of fuel within a pump chamber defined at one end of the bore. The coupling between the plunger 110 and the driveshaft 111 is realized by the tappet arrangement 100. The tappet arrangement 100 is coupled with the driveshaft 111 or the cam with the roller 102. The tappet arrangement 100 is coupled with the plunger 110 by means of the recess 107.
The wall 113 surrounds the bore with a shape that corresponds to the two flat side surface 105 and the two curved side surfaces 104. The wall 113 comprises two sections that each have the same or nearly the same radius as the two curved side surfaces 104. Each of the two curved side surfaces 104 is in contact with one section of the curved sections of the wall 113. The tappet arrangement 100 moves inside the bore 112 along the longitudinal axis L of the tappet body 101 guided by the two curved side surfaces 104 that slide along the wall 113. The two flat side surfaces 105 are arranged at a distance from the corresponding sections of the wall 113. Therefore, the tappet arrangement 100 is able to self-align its alignment with respect to the pump housing 114. The tappet arrangement 100 is able to rotate about its longitudinal axis L due to the curved side surfaces and the corresponding curved sections of the wall 113. The two flat side surfaces 105 and the corresponding sections of the wall 113 limit the rotation of the tappet arrangement 100. The distance between the flat side surfaces 105 and the wall 113 defines the given maximum angle of rotation of the tappet arrangement 100.
According to aspects, the tappet arrangement 100 slides in the bore 112 that is machined directly in the housing 114 and has the corresponding shape in the cross-section as the tappet body 101. According to further aspects, the bore 112 comprises a coating on the wall 113 for reducing friction, for example PEEK, PTFE and/or their derivates.
According to further aspects, the bore 112 comprises a separate sleeve (not shown) inserted in which the tappet arrangement 100 is arranged and movable.
According to further aspects, the wall 113 is heat treated to a desired given hardness, for example with aluminum anodising.
According to aspects, the movement of the tappet arrangement 100 in the direction of the longitudinal axis R of the roller 102 is constrained by the coupling of the tappet arrangement 100 with the plunger 110 in the recess 107. The plunger is arranged inside the recess 107 with a small clearance. The plunger 110 itself is constrained by a given clearance in its bore 112 making the plunger 110 to run in a given axial position. The clearance between the plunger 110 and the tappet arrangement 100 is necessary to compensate a misalignment of the roller 102 with respect to the cam or the driveshaft 111 due to the position of the bearings on which the driveshaft 111 sits.
The radius on the curved side surfaces 104 in combination with the clearance between the flat side surfaces 105 and the wall 113 provide a limited degree of rotation for the tappet arrangement 100. Therefore, a self-alignment of the tappet arrangement 100 with respect to the driveshaft 111 and/or the cam is realized increasing the robustness of the assembly.
The fixing 103 on top of the tappet body 101 prevents the roller 102 from touching either the tappet or the sleeve with its plane end sides. The fixing 103 comprises small spherical tips on the inside of the projecting parts 106 that run against the roller center. Therefore, the design of the roller 102 can be very simple and, thus, cost-effective. Further, the braking torque between the roller 102 and the sleeve is avoided.
The tappet arrangement 100 and the wall 113 and/or the sleeve inside the bore 112 comprise a calculated clearance on both ends at the flat side surfaces 105 avoiding special machining on the tappet arrangement end face, on the projecting parts 106 and on the bore 112.
The tappet body 101, the fixing 103 and the roller 102 are prevented to slide along the longitudinal axis R due to the recess 107 provided on the top surface 115 of the tappet body 101 where the plunger sits with a clearance smaller than the clearance between the flat side surfaces 105 and the wall 113. This feature transmits the plunger constraint to the tappet arrangement 100.
The tappet arrangement 100 comprises the advantage of self-alignment and constraint of the roller position on the cam. According to aspects, there is no need for a sleeve in the bore 112 where the tappet arrangement 100 is guided.
In the following there will be described a tappet arrangement 200 according to a second embodiment. The second embodiment is similar to the first embodiment, so that for equal parts it is referred to the description of the first embodiment. Referring to FIGS. 3A und 3B the tappet arrangement 200 comprises a tappet body 201 (or roller shoe) and a roller 202. The roller is coupled with the tappet body 201 by a fixing 203.
The roller 202 is coupled with the tappet body 201 such that the roller is able to rotate relative to the tappet body 201 about its longitudinal axis R. The fixing 203 comprises two projecting parts 206. Each of the projecting parts 206 is coupled with a plane 220 of the cylinder-shaped roller 202. Therefore, each of the projecting parts 206 comprises a spherical segment 230 that is in contact with the roller 202. The most prominent part or tip 232 of the spherical segment 230 (see also FIGS. 4) is in contact with the roller 202 in the roller center at the longitudinal axis R. The roller center on the plane 220 will be the point where the longitudinal or rotational axis R of the roller 202 passes through. Thus, the friction and the braking torque between the roller 202 and the fixing 203 is reduced. For example, the fixing 203 is made from a metallic material with elastic properties, for example brass or other metallics. The fixing 203 is a separate part to the tappet body 201 and, for example, is clipped on the tappet body 201.
As also depicted in FIG. 5 in more detail, the tappet body 201 comprises two curved side surfaces, i.e. a first side surface 2041 and a second side surface 2042. The curved side surfaces 2041 and 2042 are positioned opposite each other. The curved side surfaces are convex. The two curved side surfaces 2041 and 2042 are aligned in the direction of the longitudinal axis R of the roller 202 and in the direction of the longitudinal axis L of the tappet body 202.
Basically, it is possible that the peak of the curvature of the first side surface is on the same center line as the peak of the curvature of the second side surface, wherein the center line is a line perpendicular to the direction of the longitudinal axis of the roller. However, one of the characterizing features of FIG. 5 is that two curves that form the first and second sides surfaces 2041 and 2041 have the centres or peaks P1 and P2 on different centres lines C1 and C2, thus making the curves eccentric. In other words, the peak P1 of the curvature of the first side surface 2041 is displaced to the peak P2 of the curvature of the second side surface 2042 in direction of the longitudinal axis R of the roller. The mating sides or walls surrounding of the bore of the housing have the corresponding geometry. A clearance between the tappet body and the wall will allow the tappet body to rotate for a very limited number of degrees, without spinning around its vertical axis. This feature improves the roller alignment with the cam.
The tappet body 201 further comprises two flat side surfaces, i.e. a third and a fourth side surface 2051 and 2051, that are aligned in the direction across, in particular perpendicular to, the longitudinal axis R of the roller 202 and in the direction of the longitudinal axis L (see also FIG. 6) of the tappet body 201. The two flat side surfaces 205 each are in alignment with the two planes 230 of the roller 202.
As it further can be seen from FIG. 5, the tappet body has an elongated shape, i.e. wherein the dimension or length LS of the first 2041 and the second 2042 side surfaces in direction of the longitudinal axis R of the roller is larger than the dimension or width WS of the third 2051 and the fourth 2052 side surfaces in a direction perpendicular to the longitudinal axis R. Thus, when the tappet body 202 slides into the intended corresponding bore machined directly into the pump housing, the elongated shape of the tapped body and of the corresponding bore will prevent the tappet body to revolve against its vertical (plunger) axis L.
Referring back to the FIGS. 3 and 4, the fixing 203 comprises a base element 260 connecting the projecting parts 206. These two projecting parts or arms 206 of the fixing 203 are arranged at the respective flat side surfaces 2051 and 2052. In particular, for a tight fit of the fixing 203 to the tapped body 201 each projecting part 206 comprises a protrusion 234 being arranged on the base element near side of one projecting part 206 (or being arranged on an upper part of the projecting part 206). These protrusions 234 enable the fixing 203 to be press fit when clipped on to the tapped body 201. In summary the fixing 203 has the shape of a bracket, wherein on the inside of each projecting part or arm there are formed the respective protrusion for securing the fixing to the tappet body, and the spherical segment for preventing movement of the roller along its rotational exis.
Furthermore, each projecting part 206 comprises the spherical segment 232 being arranged on the base element distant side of one projecting part 206 (or being arranged on a lower part of the projecting part 206). The two respective the spherical segments 232 of the projecting parts 206 prevent the roller 202 from moving along its longitudinal axis R between the two flat side surfaces 2051 and 2052. The roller 202 is able to rotate about its longitudinal axis R with respect to the tappet body 201 as well as the fixing 203 and is restrained from moving in the direction of the longitudinal axis R of the roller 202 and the longitudinal axis L of the tappet body 201.
Referring to FIG. 4B, the base element 260 merges into the tapering section 270, in particular a trapezoidal section of the projecting part 206. The upper part of the projecting part having larger dimension or diameter than the lower part provides better strength against fatigue bending due to axial force from the roller.
According to a further development of the fixing, it comprises a recess 207 for coupling the tappet arrangement 200 with a plunger 210 of the high-pressure pump. This recess allows a tight fit of the plunger in the fixing 203. As can be seen from FIG. 6 the fixing 203 is arranged on a side 215 of the tappet body 201 opposite to the roller 202. Thus, also the recess 207 is arranged on the side 215 of the tappet body opposite the roller 202.
According to a further development the recess 207 can be built as an opening or through hole such that the plunger 210 can reach through the recess 207, and can abut on the side 215 of the tappet body 201.
In correspondence with FIG. 2, FIG. 6 schematically shows a detail of a high pressure pump comprising a tappet arrangement according to the second embodiment. The pump comprises a housing 214 that surrounds a bore 212. The bore 212 is surrounded by a wall 213. The plunger 210 is mounted within the bore 212. A driveshaft 211 is arranged. The driveshaft 111 comprises an engine-driven cam. As the cam is driven in use, the plunger 210 is caused to reciprocate within the bore 212 (in the direction of the axis L) and causes pressurization of fuel within a pump chamber defined at one end of the bore. The coupling between the plunger 210 and the driveshaft 211 is realized by the tappet arrangement 200. The tappet arrangement 200 is coupled with the driveshaft 211 or the cam with the roller 202. The tappet arrangement 200 is coupled with the plunger 210 by means of the recess 207 as mentioned above.
The wall 213 surrounds the bore with a shape that corresponds to the two flat side surface 2051 and 20152, as well as the two curved side surfaces 2041 and 2042. Consequently, there is an elongated bore for the elongated shaped tappet body as described above. The wall 213 comprises two sections that each have the same or nearly the same radius as the two curved side surfaces 2041 and 2042. Each of the two curved side surfaces 2041 and 2042 is in contact with one section of the curved sections of the wall 213. This is shown in detail in FIG. 7, which gives a cross-sectional view of the tappet body 201 in the bore 212 from a direction along the axis L (in FIG. 6). The tappet arrangement 200 moves inside the bore 212 along the longitudinal axis L of the tappet body 201 guided by the two curved side surfaces 204 that slide along the wall 213. The two flat side surfaces 2051 and 2052 are arranged at a distance from the corresponding sections of the wall 213. Therefore, the tappet arrangement 200 is able to self-align its alignment with respect to the pump housing 214. The tappet arrangement 200 is able to rotate about its longitudinal axis L for a very limited number of degrees due to the curved side surfaces and the corresponding curved sections of the wall 213. The two flat side surfaces 2051 and 2051 and the corresponding sections of the wall 213 as well as the elongated shape of the tappet body 201 limit the rotation of the tappet arrangement 200. The distance between the flat side surfaces 2051 and 2052, and the wall 213 defines the given maximum angle of rotation of the tappet arrangement 200.
According to further aspects, the bore 212 comprises a coating on the wall 213 for reducing friction, for example PEEK, PTFE and/or their derivates.
According to further aspects, the bore 212 could comprise a separate sleeve inserted in which the tappet arrangement 200 is arranged and movable.
According to further aspects, the wall 213 is heat treated to a desired given hardness, for example with aluminum anodising.
The radius on the curved side surfaces 2041 and 2042 in combination with the clearance between the flat side surfaces 2051 and 2052, and the wall 213 provide a limited degree of rotation for the tappet arrangement 200. Therefore, a self-alignment of the tappet arrangement 200 with respect to the driveshaft 211 and/or the cam is realized increasing the robustness of the assembly.
The tappet arrangement 200 and the wall 213 and/or the sleeve inside the bore 212 comprise a calculated clearance on both ends at the flat side surfaces 2051 and 2052 avoiding special machining on the tappet arrangement end face, on the projecting parts 206 and on the bore 212.
The tappet arrangement 200 comprises the advantage of self-alignment and constraint of the roller position on the cam. According to aspects, there is no need for a sleeve in the bore 212 where the tappet arrangement 200 is guided.

Claims

Tappet arrangement for a high pressure pump, comprising:
- a tappet body (201),

- a roller (202) arranged partly in the tappet body (201),

- a fixing (203) for holding the roller (202) in the tappet body (201) to prevent a movement of the roller (202) in direction of the longitudinal axis (R) of the roller (202), - wherein the tappet body (201) comprises:
+ a first (2041) and a second (2042) side surface arranged opposite to each other, and aligned in direction of the longitudinal axis (R) of the roller (202);

+ a third (2051) and a fourth (2052) side surface arranged opposite to each other, and aligned perpendicular to the direction of the longitudinal axis (R) of the roller,

wherein the dimension of the first (2041) and the second (2042) side surfaces in direction of the longitudinal axis (R) of the roller is larger than the dimension of the third and the fourth side surfaces perpendicular to the direction of the longitudinal axis (R) of the roller.
Tappet arrangement according to claim 1, wherein the first (2041) and the second (2042) side surfaces are curved for movable coupling the tappet arrangement with a pump housing (214) of the high pressure pump.
Tappet arrangement according to claim 2, wherein the first (2041) and the second (2042) side surfaces are curved convex with respect to the tappet body, wherein the peak of the curvature of the first (2041) side surface is displaced to the peak of the curvature of the second (2042) side surface in direction of the longitudinal axis (R) of the roller.
Tappet arrangement according to any of claims 1 to 3, the fixing (203) comprising two projecting parts (206) that each are in contact with the roller (202) to prevent a movement of the roller (202) in direction of the longitudinal axis (R) of the roller (202).
Tappet arrangement according to claims 4, wherein each of the projecting parts (206) has a spherical segment (230, 232) that is in contact with the roller (202) center at the longitudinal axis (R) to prevent the movement of the roller (202) in direction of the longitudinal axis (R) of the roller (202).
Tappet arrangement according to claims 4 or 5, wherein each of the projecting parts (206) has a protrusion (234) sticking out of the projecting part for contacting the tappet body in order to secure the fixing to the tappet body.
Tappet arrangement according to any of the claims 4 to 6, wherein each of the projecting parts has a tapering section, in particular a trapezoidal section (270).
Tappet arrangement according to any of the claims 4 to 7, wherein the fixing has a base element (260) connecting the projecting parts (206), wherein the base has a recess (207) for coupling the tappet arrangement with a plunger (210) of the high pressure pump.
Tappet arrangement according to the claims 8, wherein the base element (260) is fixed on a site (115) of the tappet body opposite the roller (102).
Tappet arrangement according to claim 7 and one of the claims 8 or 9, wherein the base element (260) merges into the tapering section of each projecting part.
Tappet arrangement according to the claims 5, 6 and 10, wherein the protrusion (234) is arranged on the base element near side of the projecting part (206), and the spherical segment (230, 232) is arranged on the base element distant side of the projecting part (206).
High pressure pump for use in an internal combustion engine, comprising:
- a plunger (210) for pressurising fuel within a pump chamber of a pump housing during a plunger pumping stroke,

- a drive shaft (111),

- a tappet arrangement (200) according to any of claims 1 to 11, the tappet arrangement (200) being coupled with the plunger (210) and the drive shaft (211) for imparting drive from the drive shaft (211) to the plunger (210) to perform the plunger pumping stroke.
Pump according to claim 12, the pump housing (214) comprising a bore (212), the shape of a wall (213) surrounding the bore (212) corresponding with the shape of the two curved side surfaces (2041, 2042) and the two curved side surfaces (2041, 2042) each being in contact with the wall (213) of the bore (212).
Pump according to claim 13, the wall (213) surrounding the bore (212) such that the two flat side surfaces (2051, 2052) are arranged at a distance from the wall (213).
Pump according to claim 13 or 14, wherein the wall (213) surrounding the bore (212) is covered by a abrasion protective coating.