JP2009293397A - Pump tappet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pump tappet capable of attaining a long service life. <P>SOLUTION: The pump tappet 21 includes a shaft 22, a roller bearing 31 arranged on the outer diameter side of the shaft 22 and rotatably supported on the shaft 22, and a case 23 holding the shaft 22 and the roller bearing 31. The roller bearing 31 comprises an outer ring 32 abutting on a cam 12a, and a plurality of rollers 33 arranged between the outer ring 32 and the shaft 22. The case 23 includes a contact surface 23j contacting an end face 32c of the outer ring 32. The surface roughness of at least one of the end face 32c of the outer ring 32 and the contact surface 23j is 0.05-0.3 μm. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pump tappet, and more particularly to a pump tappet including a roller bearing.

  Some engines such as automobiles are provided with a high-pressure pump that injects fuel at a high pressure. The high-pressure pump converts the rotational movement of the camshaft provided with the cam into the reciprocating linear movement of the pump plunger, sends the gas by the reciprocating linear movement of the pump plunger, increases the pressure in the high-pressure chamber, and injects it into the fuel chamber And supply fuel. As a constituent member of the high-pressure pump, there is a pump tappet that transmits the rotational motion of the camshaft to the pump plunger as a reciprocating linear motion. There are several types of pump tappets, such as a roller-containing tappet including rollers and a mushroom-shaped tappet, depending on the shape of the contact portion with the cam.

  Here, a technique related to a tappet for a pump including a roller bearing is disclosed in DE 10 2005 047 234 A1 (Patent Document 1). FIG. 12 is a cross-sectional view of the pump tappet shown in Patent Document 1. Referring to FIG. 12, a tappet as a roller push rod 101 shown in Patent Document 1 has a push rod housing 102 and a push rod roller 103 (roller bearing) fixed to this and supported by a needle. . The roller push rod 101 is driven by a three-stage cam 105 of a cam shaft 104 that rotates clockwise. At the same time, the roller push rod 101 is guided in the push rod guide hole 106 in the axial direction indicated by the arrow XII in FIG. 12, and drives a pump plunger 107 of a fuel high pressure pump (not shown).

The push rod roller 103 includes an outer ring 108 that contacts the three-stage cam 105, a shaft 109 disposed on the inner diameter side of the outer ring 108, and a plurality of needle rollers 110 disposed between the outer ring 108 and the shaft 109. The push rod roller 103 is a full roller type, that is, a type in which only a plurality of needle rollers 110 are disposed between the outer ring 108 and the shaft 109.
DE 10 2005 047 234 A1

  Modern high-pressure pumps are required to increase the pressure of fuel in a short time. In order to meet such a demand for high pressure in a short time, a roller bearing that is a constituent member of a pump tappet as shown in Patent Document 1 is required to be able to withstand high speed, that is, withstand high rotation. . Here, when the axial load is applied to the roller bearing during operation of the pump tappet, the roller bearing moves in the rolling axis direction of the roller. The outer ring included in the roller bearing comes into contact with the case in which the roller bearing is accommodated, but at the time of high speed rotation, seizure or wear may occur at the contact portion, and the life of the pump tappet may be shortened. .

  An object of the present invention is to provide a pump tappet capable of extending the service life.

  The pump tappet according to the present invention transmits the rotational motion of the camshaft provided with the cam to the pump plunger as a reciprocating linear motion, and performs the reciprocating linear motion together with the pump plunger. The pump tappet includes a shaft, a roller bearing disposed on the outer diameter side of the shaft and rotatably supported on the shaft, and a case for housing the shaft and the roller bearing. The roller bearing includes an outer ring that contacts the cam and a plurality of rollers disposed between the outer ring and the shaft. The case includes a contact surface that contacts an end surface of the outer ring. Here, the surface roughness Ra of at least one of the end surface and the contact surface of the outer ring is 0.05 to 0.3 μm.

  During operation of the pump tappet, the end face of the outer ring contacts the case, and seizure and wear may occur during high-speed rotation. In this case, if the value of the surface roughness Ra of the end surface and the contact surface of the outer ring is made smoother than 0.05 μm, the processing cost is greatly increased. On the other hand, if the value of the surface roughness Ra of the end surface and the contact surface of the outer ring is larger than 0.3 μm, seizure and wear are likely to occur due to the surface roughness. Therefore, by setting the surface roughness Ra of at least one of the end surface and the contact surface of the outer ring within the above range, seizure and wear of the end surface of the outer ring and the contact surface of the case can be prevented, and the pump tappet Long life can be achieved. The surface roughness Ra is defined in JIS B0601.

  Preferably, the surface roughness Ra of the end surface and the contact surface of the outer ring is 0.05 to 0.3 μm. By doing so, seizure and wear of the end face of the outer ring and the contact surface of the case can be prevented more reliably, and the life of the pump tappet can be extended.

  More preferably, the end surface of the outer ring is provided with a plurality of minute concave recesses, and the surface roughness parameter Ryni (the average value of the maximum height for each reference length) of the surface provided with the recesses is 0. 8 to 2.3 μm. By doing so, an oil film can be appropriately formed at the contact portion between the outer ring and the case. Accordingly, the life of the pump tappet can be extended.

  Here, the surface roughness parameter Ryni is the average value of the maximum height for each reference length, that is, the reference curve is extracted from the roughness curve in the direction of the average line, and the peak line and valley line of this extracted part are extracted. Is the value measured in the direction of the vertical magnification of the roughness curve (ISO 4287: 1997).

  More preferably, the roller bearing includes a cage that holds the roller. In the full-roller type bearing described in Patent Document 1, the position of the roller in the bearing is not stable during high-speed rotation, and roller skew occurs. Due to the skew of the rollers, the rollers push the roller bearings in the lateral direction, that is, in the axial direction of the shaft 109 which is the front and back direction of the drawing in FIG. Due to such lateral running of the roller bearing, there is a possibility that the end of the roller bearing becomes poorly lubricated between the roller bearing and the housing, or the roller bearing is worn.

  However, in this way, in the roller bearing that is a constituent member of the pump tappet, the position of the roller in the roller bearing during high-speed rotation can be stabilized by the cage. If it does so, the skew of a roller can be suppressed and the side running of a roller bearing can be prevented. Therefore, it is possible to reduce the risk of poor lubrication of the roller bearing and wear of the roller bearing during high-speed rotation. As a result, the life of the pump tappet can be extended.

  More preferably, the surface roughness Ra of the end face of the cage is 0.05 to 0.3 μm. During operation of the pump tappet, the end face of the cage contacts the case, and seizure and wear may occur during high-speed rotation. In this case, if the value of the surface roughness Ra of the end face of the cage is smoothed to be less than 0.05 μm, the processing cost is greatly increased. Further, if the value of the surface roughness Ra of the end face of the cage is larger than 0.3 μm, seizure and wear are likely to occur due to the roughness of the surface. Therefore, by setting the surface roughness Ra of the end face of the cage within the above range, seizure and wear of the end face of the cage can be prevented, and the life of the pump tappet can be extended.

  According to the pump tappet according to the present invention, since the surface roughness Ra of at least one of the end surface and the contact surface of the outer ring is 0.05 to 0.3 μm, the end surface of the outer ring and the contact surface of the case are baked. Prevents sticking and wear, and can extend the life of the pump tappet.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a part of a high-pressure pump including a pump tappet (hereinafter simply referred to as “tappet”) according to an embodiment of the present invention. 2 and 3 are sectional views of tappets included in the high-pressure pump shown in FIG. FIG. 4 is a schematic perspective view of the tappet shown in FIGS. 2 and 3. FIG. 5 is a view of the tappet shown in FIG. 4 as viewed from the direction of the arrow V in FIG. 6 is a view of the tappet shown in FIG. 4 as viewed from the direction of the arrow VI in FIG. 7 is a view of the tappet shown in FIG. 4 as viewed from the direction of arrow VII in FIG. 8 is a view of the tappet shown in FIG. 4 as viewed from the direction of arrow VIII in FIG. 2 corresponds to the II-II cross section shown in FIG. 5, and FIG. 3 corresponds to the III-III cross section shown in FIG. In addition, in the figure shown below, illustration of hatching of the cross section of a roller is abbreviate | omitted from a viewpoint of easy understanding.

  With reference to FIGS. 1-8, the structure of the high pressure pump containing the tappet which concerns on one Embodiment of this invention is demonstrated first. A high pressure pump 11 including a tappet according to an embodiment of the present invention has a cam 12a provided on the outer diameter side thereof, a camshaft 12 that rotates in the direction of arrow A in FIG. The tappet 21 that abuts and transmits the rotary motion of the camshaft 12 as a reciprocating linear motion to the pump plunger 13 (hereinafter simply referred to as “plunger”) and performs the reciprocating linear motion, and the reciprocating linear motion abutting the tappet 21. A plunger 13 as a rod-shaped member that moves, a high-pressure chamber (not shown) that feeds gas in accordance with the reciprocating linear motion of the plunger 13, abuts against the tappet 21, and moves the plunger 13 inward. And a housing 15 that houses the tappet 21, the plunger 13, and the spring 14.

  The tappet 21, the plunger 13, and the spring 14 are arranged so as to be accommodated in the opening hole 16 provided in the housing 15. The tappet 21 is guided by the inner diameter surface 16a of the opening hole 16 in the vertical direction in FIG. 1, that is, in the direction of the arrow I in FIG.

  The camshaft 12 and the tappet 21 are arranged so that the outer diameter surface 12b of the cam 12a and the outer diameter surface 32a of the outer ring 32 provided in the roller bearing 31 included in the tappet 21 abut. One end 13 a of the plunger 13 is disposed so as to abut on an intermediate bottom 23 c provided in a case 23 included in the tappet 21. The spring 14 is disposed such that one end portion 14a thereof abuts against a spring seat 17 provided on the lower side of the intermediate bottom 23c.

  The spring 14 has an elastic force in the downward direction, that is, in the direction opposite to the direction indicated by the arrow I in FIG. The tappet 21 is urged upward by the elastic force of the spring 14 through the plunger 13, that is, in the direction indicated by the arrow I in FIG. 1.

  The tappet 21 and the plunger 13 are moved in the vertical direction, that is, in the direction of the arrow I in FIG. 1 or vice versa, by the rotational movement of the camshaft 12, the urging of the spring 14, and the guide of the inner diameter surface 16a of the opening hole 16. Reciprocating linear motion in the direction of. The reciprocating linear motion here is a motion in the direction of arrow I in FIG. 1 or in the opposite direction. The tappet 21 performs a reciprocating linear motion in the direction of the arrow I in FIG. When the camshaft 12 rotates at a high speed, the speed of the reciprocating linear motion of the tappet 21 and the plunger 13 also increases.

  The high pressure chamber is disposed on the other end side (not shown) of the plunger 13. The reciprocating linear motion of the plunger 13 can increase the pressure of the fuel supplied to the high pressure chamber.

  Next, the configuration of the tappet 21 according to an embodiment of the present invention will be described. The tappet 21 includes a shaft 22, a roller bearing 31 that is disposed on the outer diameter side of the shaft 22 and is rotatably supported on the shaft 22, and a case 23 that houses the shaft 22 and the roller bearing 31.

  The case 23 includes a cylindrical peripheral wall 23a and an intermediate bottom 23c provided at an intermediate position of the inner diameter surface 23b of the peripheral wall 23a so as to partition the space in the vertical direction. Of the case 23, the intermediate bottom 23 c is in contact with the plunger 13. The peripheral wall 23a and the intermediate bottom 23c have a predetermined thickness.

  A pair of support holes 23d and 23e that support the shaft 22 are provided on one end side of the peripheral wall 23a. The shaft 22 is arranged so that the shaft 22 is inserted into the pair of support holes 23d and 23e. A roller bearing 31 is disposed on the outer diameter side of the shaft 22. Thus, the case 23 accommodates the shaft 22 and the roller bearing 31 in the space 23f from the intermediate bottom 23c toward the one end side of the peripheral wall 23a.

  A part of the plunger 13 is accommodated in the space 23g from the intermediate bottom 23c toward the other end side of the peripheral wall 23a. Specifically, the one end portion 13a of the plunger 13 is disposed so as to contact the central portion in the radial direction of the intermediate bottom 23c, and the one end portion 13a of the plunger 13 is accommodated. The one end portion 14a of the spring 14 is also accommodated in the space 23g.

  The middle bottom 23c is provided with four oil holes 25 penetrating in the thickness direction (see FIGS. 7 and 8). The four oil holes 25 are provided so as to avoid a contact portion between the one end portion 13a of the plunger 13 and the intermediate bottom 23c. By using this oil hole 25, the lubricating oil supplied to the tappet 21 can be passed between the space 23f and the space 23g.

  The case 23 is provided with a through hole 23i that penetrates from the outer diameter surface 23h to the inner diameter surface 23b of the peripheral wall 23a. A positioning pin 24 is fitted in the through hole 23i. The positioning pin 24 is a cylindrical member. The positioning pin 24 is configured such that a part thereof protrudes from the outer diameter surface 23h when fitted into the through hole 23i. A concave groove 16b extending in the direction of arrow I in FIG. 1 is provided on the inner diameter surface 16a of the opening hole 16 of the housing 15 so as to be recessed from the inner diameter surface 16a. When the tappet 21 is accommodated in the opening hole 16, the protruding portion of the positioning pin 24 is fitted into the concave groove 16b. Thereby, the case 23 in the opening hole 16, and the positioning of the tappet 21 in the circumferential direction is performed. Thereby, rotation to the circumferential direction of the tappet 21 in the opening hole 16 can be prevented.

  Next, the configuration of the roller bearing 31 included in the tappet 21 will be described. FIG. 9 is an enlarged view of a portion indicated by IX of a two-dot chain line in FIG. A roller pitch circle 31a is indicated by a one-dot chain line in FIG. FIG. 10 is a view of a part of the roller bearing 31 seen from the direction of the arrow X shown in FIG. FIG. 11 is a cross-sectional view showing a part of the roller bearing 31, and is a XI-XI cross section in FIG. 1 to 11, the roller bearing 31 includes an outer ring 32, a plurality of rollers 33 disposed between the outer ring 32 and the shaft 22, and a cage 34 that holds the plurality of rollers 33. .

  The retainer 34 includes a pair of annular portions 34 a and 34 b and a plurality of column portions 34 d that connect the pair of annular portions 34 a and 34 b so as to form a pocket 34 c that accommodates the rollers 33. The column portion 34d has a shape that extends straight in the axial direction, that is, in the cross section shown in FIG.

  Similar to the rollers 33, the retainer 34 is disposed between the outer ring 32 and the shaft 22. The plurality of rollers 33 are accommodated and held in the respective pockets 34 c provided in the cage 34. The retainer 34 is configured such that the outer diameter guide, that is, the inner diameter surface 32 b of the outer ring 32 disposed on the outer diameter side of the retainer 34 and the outer diameter surface 34 e of the retainer 34 are in radial contact. Further, the retainer 34 is provided with an oil groove 34f so as to be recessed inward from the outer diameter surface 34e. The oil groove 34f is provided at the center of the column portion 34d and has a shape extending in the circumferential direction.

  During the rotational movement of the camshaft 12, that is, when the tappet 21 is in operation, the end surface 32c of the outer ring 32 is in contact with the contact surface 23j of the case 23. Here, the surface roughness Ra of at least one of the end surface 32c of the outer ring 32 and the contact surface 23j of the case 23 is 0.05 to 0.3 μm.

  During high-speed rotation, there is a risk of causing an oil film breakage at this contact portion. Then, abnormal wear occurs in the outer ring 32 and the case 23 due to poor lubrication, and the life of the tappet 21 cannot be extended. However, by configuring as described above, an oil film can be appropriately formed at the contact portion between the outer ring 32 and the case 23 even during high-speed rotation. If it does so, the oil film cut | disconnection in a contact part can be prevented. Therefore, abnormal wear of the end surface 32c of the outer ring 32 and the contact surface 23j of the case 23 can be prevented, and the life of the tappet 21 can be extended.

  When the tappet 21 is in operation, the end face 32c of the outer ring 32 is in contact with the case 23, and seizure or wear may occur during high-speed rotation. In this case, if the value of the surface roughness Ra of the end surface 32c of the outer ring 32 and the contact surface 23j is smoothed to be less than 0.05 μm, the processing cost is greatly increased. On the other hand, if the value of the surface roughness Ra of the end face 32c of the outer ring 32 and the contact surface 23j is larger than 0.3 μm, seizure and wear are likely to occur due to the roughness of the surface. Therefore, seizure and wear of the end surface 32c of the outer ring 32 and the contact surface 23j of the case 23 are prevented by setting the surface roughness Ra of at least one of the end surface 32c and the contact surface 23j of the outer ring 32 within the above range. Thus, the life of the tappet 21 can be extended.

  The surface roughness Ra of the end surface 32c of the outer ring 32 and the contact surface 23j of the case 23 may be 0.05 to 0.3 μm. By doing so, seizure and wear of the end surface 32c of the outer ring 32 and the contact surface 23j of the case 23 can be prevented more reliably, and the life of the tappet 21 can be extended.

  Here, a plurality of minute concave recesses are provided on the end surface 32c of the outer ring 32, and the surface roughness parameter Ryni of the surface provided with the recesses may be set to 0.8 to 2.3 μm. By doing so, an oil film can be appropriately formed at the contact portion between the outer ring 32 and the case 23. Therefore, the life of the tappet 21 can be extended.

  Due to the rotational movement of the camshaft 12, the outer ring 32 and the rollers 33, which are constituent members of the roller bearing 31, are also rotated. When the camshaft 12 rotates at a high speed, the rotation of the rollers 33 also increases. Here, in the roller bearing 31 which is a constituent member of the tappet 21, the position of the roller 33 in the roller bearing 31 at the time of high speed rotation can be stabilized by the cage 34. Then, the skew of the roller 33 can be suppressed and the lateral running of the roller bearing 31 can be prevented. Accordingly, it is possible to reduce the risk of poor lubrication of the roller bearing 31 and wear of the roller bearing 31 during high-speed rotation.

  In addition, the high-pressure pump 11 includes the tappet 21 that can reduce the risk of poor lubrication of the roller bearing 31 and wear of the roller bearing 31 during high-speed rotation. High pressure can be achieved.

  Here, the retainer 34 is an outer diameter guide, and the retainer 34 and the outer ring 32 are provided on the outer diameter surface 34e of the retainer 34 because an oil groove 34f that is recessed inward from the surface is provided. And the radial position of the cage 34 can be stabilized. Further, the oil permeability of the inner diameter surface 34g of the cage 34 and the outer diameter surface 22a of the shaft 22 is improved, and the lubricity between the outer diameter surface 34e of the cage 34 and the inner diameter surface 32b of the outer ring 32 is improved and retained. Wear of the vessel 34 and the outer ring 32 can be suppressed. Therefore, the life of the cage 34, the rollers 33, the outer ring 32, and the shaft 22 can be extended. The oil groove may be provided so as to extend with an inclination in the axial direction, or may be provided so as to extend in a curved manner. A plurality of oil grooves may be provided.

  The cage 34 is an inner diameter guide, and an oil groove may be provided on the inner diameter surface 34 g of the cage 34. By carrying out like this, the holder | retainer 34 and the shaft 22 can be made to contact and the radial position of the holder | retainer 34 can be stabilized. Further, the oil permeability of the outer diameter surface 34e of the cage 34 and the inner diameter surface 32b of the outer ring 32 is improved, and the lubricity between the inner diameter surface 34g of the cage 34 and the outer diameter surface 22a of the shaft 22 is improved and retained. Wear of the vessel 34 and the shaft 22 can be suppressed. Therefore, the life of the cage 34, the rollers 33, the outer ring 32, and the shaft 22 can be extended.

  The cage 34 provided in the roller bearing 31 may be made of resin. By carrying out like this, the holder | retainer 34 itself can be made lightweight and the weight of the tappet 21 can be lightened generally. Therefore, the force required for the reciprocating linear motion, here, the force required for the vertical movement of the tappet 21 can be reduced. Further, when the cage 34 is made of resin, it can be manufactured by injection molding or the like, so that mass production is facilitated and it can be manufactured at low cost. Examples of the material of the cage 34 include nylon 66, nylon 46, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), and the like. If necessary, the resin may be filled with carbon fiber, glass fiber, carbon black, or the like.

  Here, the surface roughness Ra of the end surface 34i of the cage 34 is preferably 0.05 to 0.3 μm. When the tappet 21 is in operation, the end face 34i of the cage 34 contacts the case 23, and seizure or wear may occur during high-speed rotation. In this case, if the value of the surface roughness Ra of the end surface 23i of the cage 23 is made smoother than 0.05 μm, the processing cost is greatly increased. Further, if the value of the surface roughness Ra of the end face 34i of the cage 34 is larger than 0.3 μm, seizure and wear are likely to occur due to the roughness of the surface. Therefore, by setting the surface roughness Ra of the end surface 34i of the retainer 34 within the above range, seizure and wear of the end surface 34i of the retainer 34 can be prevented, and the life of the tappet 21 can be extended.

  In FIG. 10, the dimension of the clearance between the rolling surface 33a of the roller 33 accommodated in the pocket 34c and the side wall surface 34h of the column portion 34d is exaggerated and greatly illustrated from the viewpoint of easy understanding. .

  In addition, the roller and shaft which comprise the above-mentioned tappet are manufactured by forging, cutting, etc., steel members, for example, SUJ2 and SCM420 (all are JIS standards).

  In the above-described embodiment, the cage includes a pair of annular portions and a plurality of column portions, but is not limited thereto, and is divided into a plurality of members instead of an integrated type, A spacer-type cage disposed between the rollers may be used.

  In the above embodiment, the column portion has a shape extending straight in the axial direction. However, the present invention is not limited to this, and the column portion may be bent in the radial direction. It may be shaped like an M-type cage. Furthermore, it is good also as providing the roller stop part which prevents the fall-off | omission of the roller of the radial direction on the side wall surface of a pillar part.

  In the above-described embodiment, the roller bearing is configured to include a cage that holds a plurality of rollers. However, the configuration is not limited thereto, that is, a configuration in which the roller bearing does not include a cage, that is, a full-roller type. The same applies to roller bearings.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  The tappet according to the present invention is included in a high-pressure pump that supplies fuel to an engine of an automobile or the like, and is effectively used as an automobile part.

It is sectional drawing which shows a part of high-pressure pump containing the tappet which concerns on one Embodiment of this invention. It is sectional drawing of the tappet contained in the high pressure pump shown in FIG. It is sectional drawing of the tappet contained in the high pressure pump shown in FIG. FIG. 4 is a perspective view of the tappet shown in FIGS. 2 and 3. It is the figure which looked at the tappet shown in FIG. 4 from the direction of arrow V in FIG. It is the figure which looked at the tappet shown in FIG. 4 from the direction of arrow VI in FIG. It is the figure which looked at the tappet shown in FIG. 4 from the direction of arrow VII in FIG. It is the figure which looked at the tappet shown in FIG. 4 from the direction of arrow VIII in FIG. It is an enlarged view of the part shown by IX of the tappet shown in FIG. It is the figure which looked at a part of roller bearing contained in the tappet shown in FIG. 2 from the direction of the arrow X in FIG. FIG. 10 is a partial cross-sectional view of a roller bearing included in the tappet illustrated in FIG. 2, and is a view cut along a XI-XI cross section in FIG. 9. It is sectional drawing which shows the tappet as a conventional roller pushrod.

Explanation of symbols

  11 High pressure pump, 12 Cam shaft, 12a Cam, 12b, 22a, 23h, 32a, 34e Outer diameter surface, 13 Plunger, 13a, 14a End, 14 Spring, 15 Housing, 16 Open hole, 16a, 23b, 32b, 34 g Inner surface, 16 b Groove, 17 Spring seat, 21 Tappet, 22 Shaft, 23 Case, 23 a Circumferential wall, 23 c Intermediate bottom, 23 d, 23 e Support hole, 23 f, 23 g Space, 23 i Through hole, 23 j Contact surface, 24 Positioning pin , 25 Oil hole, 31 Roller bearing, 31a Roller pitch circle, 32 Outer ring, 32c, 34i End face, 33 Roller, 33a Rolling surface, 34 Cage, 34a, 34b Annular part, 34c Pocket, 34d Pillar part, 34f Oil groove 34h Side wall surface.

Claims (5)

A pump tappet that transmits the rotational motion of a camshaft provided with a cam to a pump plunger as a reciprocating linear motion, and performs a reciprocating linear motion together with the pump plunger,
A shaft, a roller bearing disposed on the outer diameter side of the shaft and rotatably supported on the shaft, and a case for housing the shaft and the roller bearing;
The roller bearing includes an outer ring that contacts the cam, and a plurality of rollers disposed between the outer ring and the shaft,
The case includes a contact surface that contacts an end surface of the outer ring,
A tappet for a pump, wherein the surface roughness Ra of at least one of the end surface of the outer ring and the contact surface is 0.05 to 0.3 μm. The tappet for pumps according to claim 1 whose surface roughness Ra of the end face of said outer ring and said contact surface is 0.05-0.3 micrometer. The end surface of the outer ring is provided with a plurality of minute concave recesses,
The tappet for pumps according to claim 1 or 2 whose surface roughness parameter Ryni (average value of maximum height for every reference length) of a surface provided with a hollow is 0.8-2.3 micrometers. The said roller bearing is a tappet for pumps in any one of Claims 1-3 provided with the holder | retainer which hold | maintains a roller. The tappet for pumps of Claim 4 whose surface roughness Ra of the end surface of the said holder | retainer is 0.05-0.3 micrometer.

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