CN210343565U - Plunger pump and high-pressure fuel pump - Google Patents

Abstract

The utility model provides a plunger pump and high-pressure fuel pump. The plunger pump includes: a pump body having an inner wall and defining a longitudinal axis; a plunger disposed in the pump body and extending along the longitudinal axis; and a tappet assembly disposed in the pump body and reciprocally movable along the longitudinal axis to drive the plunger. The tappet body assembly includes a tappet body having an outer circumferential surface facing the inner wall of the pump body. The pump body has a first rotation limiting feature and the tappet has a second rotation limiting feature, the first rotation limiting feature cooperating with the second rotation limiting feature to limit rotation of the tappet about the longitudinal axis relative to the pump body. According to the utility model discloses, can restrict the rotation of tappet body for the pump body around the longitudinal axis of the pump body for contactless between roller terminal surface and the tappet body or contact as few as possible, thereby wearing and tearing between the two can reduce. This ensures reliable operation of the plunger pump and extends the service life of the plunger pump.

Description

Plunger pump and high-pressure fuel pump

Technical Field

The utility model relates to a plunger pump to and including the high pressure fuel pump of this kind of plunger pump.

Background

In a fuel injection system for a vehicle engine, a high-pressure fuel pump supplies fuel to a common rail in a high-pressure state. The high-pressure fuel pump mainly includes a supply pump and one or more plunger-type high-pressure components (plunger pumps). Plunger pumps typically include a plunger disposed within a pump body and reciprocable by a cam on a camshaft through a tappet assembly. The tappet body assembly includes a tappet body and a roller rotatably supported by a pin in an inner cavity of the tappet body. The roller is free to rotate about an axis of rotation defined by the pin and projects out of the cavity to contact the contoured surface of the cam. The plunger spring is arranged between the plunger sleeve and the tappet body of the tappet body component. One end of the plunger spring is fixed against the plunger sleeve and the other end is against a spring seat formed on the tappet body to continuously apply a spring force that urges the spring seat, particularly the roller, toward the cam, thereby keeping the roller in close contact with the contoured surface of the cam.

When the plunger pump works, the tappet body assembly and the plunger piston do reciprocating motion under the action of the rotating motion of the cam shaft and the spring force of the plunger piston spring, so that the oil pumping task is finished. The plunger spring is usually in the form of a helical spring which, when compressed and extended, causes the tappet against which it abuts to rotate relative to the pump body about the longitudinal axis of the pump body. Because of the tolerance or clearance between the tappet body of the tappet body assembly and the roller, this relative rotation in turn causes the roller to slide along the pin, thereby causing one end surface of the roller to contact and push against a corresponding portion of the tappet body. Of course, such relative rotation is also possible to bring the two end faces of the roller into alternate contact with the respective end walls of the tappet body. The long-term frictional contact between the roller end face and the tappet body not only causes the abrasion of the roller end face and the tappet body and shortens the service life, but also generates additional heat and causes the performance degradation of the plunger pump.

Thus, there is a significant need for improvements to existing plunger pumps to limit rotation of the tappet relative to the pump body about the longitudinal axis of the pump body.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a plunger pump, the very cylinder receives the restriction for the rotation of the pump body round the longitudinal axis of the pump body in this kind of plunger pump to ensure plunger pump's reliable operation.

According to an aspect of the utility model, a plunger pump is provided, plunger pump includes: a pump body having an inner wall and defining a longitudinal axis; a plunger disposed in the pump body and extending along the longitudinal axis; and a tappet assembly disposed in the pump body and reciprocally movable along the longitudinal axis to drive the plunger, the tappet assembly including a tappet having an outer circumferential surface facing an inner wall of the pump body; wherein the pump body has a first rotation limiting feature and the tappet has a second rotation limiting feature, the first rotation limiting feature cooperating with the second rotation limiting feature to limit rotation of the tappet about the longitudinal axis relative to the pump body.

Preferably, one of the first and second rotation limiting features is a protrusion and the other of the first and second rotation limiting features is a flat surface extending parallel to the longitudinal axis.

Preferably, the protrusion engages the flat surface in a sliding or rolling friction manner as the tappet reciprocates along the longitudinal axis.

Preferably, the projection is in the form of a guide pin extending parallel to the planar surface.

Preferably, the projection is in the form of a guide roller extending parallel to the planar surface and capable of rolling on the planar surface.

Preferably, the protrusion protrudes from an inner wall of the pump body, and the flat surface is formed on the outer circumferential surface of the tappet body.

Preferably, one of the first and second rotation limiting features is a protrusion and the other of the first and second rotation limiting features is a groove extending along the longitudinal axis, the protrusion being received in the groove to enable the protrusion to move along the longitudinal axis.

Preferably, the protrusion engages the groove in a sliding or rolling friction manner as the tappet reciprocates along the longitudinal axis.

Preferably, the projection is a guide bolt, one end of which is received in the recess.

Preferably, the projection is part of a guide ball received in and protruding from a recess, the guide ball being able to roll in the groove.

Preferably, the protrusion protrudes from an inner wall of the pump body, and the groove is formed in the outer circumferential surface of the tappet body.

According to another aspect of the invention, a high-pressure fuel pump is provided, which comprises at least one high-pressure component for outputting high-pressure fuel, which high-pressure component is formed by the above-mentioned plunger pump.

According to the utility model discloses, through providing rotation restriction characteristic on the tappet body and the pump body respectively, the tappet body receives the restriction for the rotation of the pump body around the longitudinal axis of the pump body for contactless between roller terminal surface and the tappet body or contact as few as possible, thereby wearing and tearing between the two can reduce. This ensures reliable operation of the plunger pump and extends the service life of the plunger pump.

Drawings

The above-described and other aspects of the present invention will be more fully understood and appreciated in view of the accompanying drawings. It should be noted that the figures are merely schematic and are not drawn to scale. In the drawings:

FIG. 1A is a schematic cross-sectional view of a portion of a plunger pump according to one embodiment of the present application;

FIG. 1B is another schematic cross-sectional view of a portion of the plunger pump of FIG. 1A;

FIGS. 1C and 1D are schematic side and top views, respectively, of a rotation limiting feature of the plunger pump of FIG. 1A;

FIG. 2A is a cross-sectional schematic view of a portion of a plunger pump according to another embodiment of the present application;

fig. 2B and 2C are schematic side and top views, respectively, of the rotation limiting feature of the plunger pump of fig. 2A;

FIG. 3A is a cross-sectional schematic view of a portion of a plunger pump according to yet another embodiment of the present application;

FIG. 3B is a schematic top cross-sectional view of the rotation limiting feature of the plunger pump of FIG. 3A;

FIGS. 4A and 4B are schematic side and top views, respectively, of a portion of a plunger pump according to yet another embodiment of the present application; and

fig. 5A and 5B are a schematic side cross-sectional view and a top view, respectively, of a portion of a plunger pump according to yet another embodiment of the present application.

Detailed Description

The preferred embodiments of the present invention will be described in detail below with reference to examples. It will be understood by those skilled in the art that these exemplary embodiments are not meant to form any limitation of the present invention.

The present application relates to a plunger pump. Such a plunger pump can be used in a high-pressure fuel pump, in particular a high-pressure diesel pump, for a vehicle. The high-pressure fuel pump mainly includes a supply pump and one or more plunger-type high-pressure components (plunger pumps). The supply pump draws fuel from the fuel tank and pre-pressurizes the fuel, and then supplies the pre-pressurized fuel to the plunger pump. The plunger pump pressurizes fuel to a high pressure and supplies the high pressure fuel to the engine, such as via a rail of a common rail system.

Fig. 1A shows a part of a plunger pump 1 according to an embodiment of the present application. As shown in fig. 1A, the plunger pump 1 may include: a pump body 3, the pump body 3 having an inner wall (37) and defining a longitudinal axis 4; a plunger sleeve (not shown) mounted in the pump body 3; a plunger 5 reciprocable in the plunger sleeve along a longitudinal axis 4; a camshaft (not shown) on which a cam 7 is provided; a tappet body assembly including a tappet body 9 and a roller 15 rotatably supported by a pin 11 in an inner cavity 13 of the tappet body 9; and a plunger spring 17 arranged between the plunger sleeve and the tappet body 9 of the tappet body assembly.

With further reference to fig. 1B, the tappet 9 is substantially cylindrical in shape, with its longitudinal axis substantially coinciding with the longitudinal axis 4 of the pump body 3. The tappet 9 also has an outer peripheral surface 10 facing the inner wall 37 of the pump body 3. The tappet body 9 defines therein an inner cavity 13 in the lower part and a spring seat 19 in the upper part. In a transverse direction of the tappet body 9 perpendicular to the longitudinal axis 4, the inner cavity 13 is delimited by two end walls 23, 25 facing each other, in which two end walls 23, 25 pin holes aligned with each other along the transverse direction are formed. The roller 15 is mounted in the inner cavity 13 of the tappet body 9 by means of the pin 11, and the two end faces 27, 29 of the roller 15 are respectively facing the two end walls 23, 25 of the tappet body 9 with a clearance (fitting tolerance) such that the roller 15 can rotate in the inner cavity 13. The pin 11 passes through the roller 15 and defines a rotation axis 12 about which the roller 15 freely rotates, and the pin 11 is inserted and fixed in the pin hole at both ends. The axis of rotation 12 is parallel to the transverse direction. Due to the presence of said gap, the roller 15 can also slide on the pin 11 along the axis of rotation 12.

Referring again to fig. 1A, the roller 15 protrudes from the cavity 13 and is contactable with the contoured surface 21 of the cam 7 and is driven by the cam 7. The plunger 5 extends along a longitudinal axis 4, one end of which is inserted into the plunger sleeve and the other end of which is pushed against the tappet body 9, for example against a boss in the spring seat 19. The plunger spring 17 is typically in the form of a helical spring, one end of which is fixed against the plunger sleeve and the other end of which abuts a spring seat 19, and the plunger spring 17 holds the plunger 5 against the tappet 9 by means of a clamping disc 31 located in the spring seat 19 and clamped at the end of the plunger 5. The plunger spring 17 continues to exert a spring force that urges the spring seat 19, and in particular the roller 15, towards the cam 7, thereby maintaining the roller 15 in close contact with the contoured surface 21 of the cam 7.

During the operation of the plunger pump 1, the tappet assembly and the plunger 5 reciprocate along the longitudinal axis 4 under the rotation of the camshaft and the spring force of the plunger spring 17, thereby completing the oil pumping task. The plunger spring 17, when it compresses and extends, brings the tappet 9 against which it abuts into rotation about the longitudinal axis 4 with respect to the pump body 3. At this point, due to the presence of said gap, roller 15 slides on pin 11 in said transverse direction, bringing one of the two end faces 27, 29 of roller 15 into contact with the respective end wall 23, 25 of tappet 9. Of course, it is also possible for this relative rotation to bring the two end faces 27, 29 of the roller 15 into alternate contact with the respective end walls 23, 25 of the tappet.

The long-term frictional contact between the end faces 27, 29 of the rollers 15 and the tappet body 9 not only causes wear of both, shortening the service life, but also generates additional heat, causing deterioration of the performance of the plunger pump 1. In order to solve this problem, the present application proposes to provide a first and a second rotation limiting feature on the pump body 3 and on the tappet 9, respectively, to limit as much as possible the rotation of the tappet 9 about the longitudinal axis 4 with respect to the pump body 3.

In fig. 1A, 1C and 1D, a first rotation limiting feature in the form of a protrusion 35 protruding from an inner wall 37 of the pump body 3 and a second rotation limiting feature in the form of a flat surface 33 formed on the outer circumferential surface 10 of the tappet 9 and extending parallel to the longitudinal axis 4 of the plunger pump 1 according to one embodiment of the present application are shown. The flat surfaces 33 may be formed by means known in the art (e.g., milling, casting, etc.) and preferably extend parallel to the axis of rotation 12 of the roller 15. The projection 35 can cooperate with this flat surface 33 to limit the rotation of the tappet 9 about the longitudinal axis 4 with respect to the pump body 3. With particular reference to fig. 1C and 1D, the projection 35 may be in the form of a guide pin that is generally cylindrical and has two end faces and a side face extending between the two end faces. The guide pins extend parallel to the flat surface 33 and preferably perpendicular to the longitudinal axis 4. Said guide pins may be fixed to the inner wall 37 of the pump body 3 by means known in the art (for example welding, etc.) and protrude from the inner wall 37 of the pump body 3 when it is mounted in position. During operation of the plunger pump 1, the edge 38 of the side of said guide pin remote from the inner wall 37 is able to cooperate with the flat surface 33, allowing the reciprocating movement of the tappet 9 inside the pump body 3 along the longitudinal axis 4, while limiting the rotation of the tappet 9 about the longitudinal axis 4 with respect to the pump body 3.

It should be understood that a projection may also be provided on the tappet 9, and the inner wall 37 of the pump body 3 may be correspondingly formed with a flat surface, provided that said projection can cooperate with said flat surface to define the rotation of the tappet 9 about the longitudinal axis 4 with respect to the pump body 3. It should also be understood that the particular form of the projection is not limited to a guide pin, but may comprise any protruding feature able to cooperate with said flat surface to limit the rotation of the tappet 9 about the longitudinal axis 4 with respect to the pump body 3. It will also be appreciated that the flat surface may also extend at an angle to the axis of rotation 12 of the roller 15. It should also be understood that the flat surface may be more than one flat surface and that the projection may also be more than one projection cooperating with said more than one flat surface to define the rotation of the tappet 9 about the longitudinal axis 4 with respect to the pump body 3.

Fig. 2A shows a part of a plunger pump 1' according to another embodiment of the present application. Similar to plunger pump 1, the second rotation limiting feature of plunger pump 1' is in the form of a flat surface 33 formed on outer circumferential surface 10 of tappet 9 and extending parallel to longitudinal axis 4. In order to reduce the friction between the flat surface and the protrusion, the present application proposes that the plunger pump 1 'employ a guide roller as the protrusion 35' instead of the above-described guide pin. With further reference to fig. 2B and 2C, the guide roller is connected to the pump body 3 by a guide roller pin 41 and protrudes from the inner wall 37 of the pump body 3 and is rotatable about an axis of rotation 39 parallel to the flat surface 33. Said guide roller can cooperate with said flat surface 33 in a similar way to said guide pin to limit the rotation of the tappet 9 about the longitudinal axis 4 with respect to the pump body 3, while said guide roller can roll on the flat surface 33 in the direction of the longitudinal axis 4 to reduce the friction between the flat surface 33 and the projection 35'. The use of guide rollers converts the friction between the flat surface 33 and the protrusion 35' from sliding friction to rolling friction, which reduces the increased system friction loss due to the introduction of the rotation limiting feature, improves the transmission efficiency, and extends the component life, compared to the use of guide pins. It is understood that said guide rollers can be connected to the pump body 3 in any manner known in the art. It should also be understood that more than one guide roller may be provided. It should also be understood that guide rollers may also be provided on the tappet 9 and the inner wall 37 of the pump body 3 may be correspondingly formed with a flat surface, said guide rollers cooperating with said flat surface to limit the rotation of the tappet 9 about the longitudinal axis 4 with respect to the pump body 3 and to provide rolling friction between the flat surface 33 and the projection 35'.

Fig. 3A shows a part of a plunger pump 1 "according to yet another embodiment of the present application. The plunger pump 1 "differs from the plunger pump 1 in that: the second rotation limiting feature is in the form of a groove 43 formed in the outer circumferential surface 10 of the tappet body 9 and extending parallel to the longitudinal axis 4. The groove 43 may be formed by means known in the art (e.g., milling, casting, etc.). The projection 35 "can be received in the groove 43 to cooperate with the groove 43 to limit the rotation of the tappet 9 about the longitudinal axis 4 with respect to the pump body 3. In fig. 3A, the projection 35 "is in the form of a guide bolt which can be fixed to the pump body 3 in a manner known in the art, for example said guide bolt can be screwed into the pump body 3 via a threaded hole provided in the pump body 3 and projects from the inner wall 37 of the pump body 3. As best shown in fig. 3B, the end 45 of said guide bolt protrudes from the pump body 3 and is received in the groove 43 of the tappet 9, so that the end 45 can move along the longitudinal axis 4 with respect to the groove 43. During operation of the plunger pump 1, the end 45 of said guide bolt cooperates with the groove 43, allowing the tappet 9 to reciprocate along the longitudinal axis 4 inside the pump body 3, while limiting the rotation of the tappet 9 about the longitudinal axis 4 with respect to the pump body 3.

It should be understood that the particular form of projection 41 is not limited to a guide bolt, but may comprise any protruding feature capable of cooperating with groove 43 of tappet 9 to limit the rotation of tappet 9 about longitudinal axis 4 with respect to pump body 3. It is also understood that the groove 43 may be more than one groove and the projection 41 may be more than one projection cooperating with said more than one groove to define the rotation of the tappet 9 about the longitudinal axis 4 with respect to the pump body 3.

Fig. 4A and 4B show a part of a plunger pump 1 "' according to yet another embodiment of the present application. The plunger pump 1 "' differs from the plunger pump 1 in that: the first rotation limiting feature is in the form of a groove 49 formed in the inner wall 37 of the pump body 3 and extending parallel to the longitudinal axis 4, and the second rotation limiting feature is in the form of a protrusion 47 protruding from the outer circumferential surface 10 of the tappet 9. The groove 49 may be formed by means known in the art (e.g., milling, casting, etc.). Projection 47 may be fixed to lifter 9 by means known in the art (e.g., welding, etc.), or it may be formed integrally with lifter 9. The protrusion 47 may be received in the groove 49 to limit rotation of the tappet 9 about the longitudinal axis 4. As shown in fig. 4A and 4B, the projection 47 protrudes from the outer circumferential surface 10 of the tappet body 9 and is received in the groove 49 such that the projection 47 is movable relative to the groove 49 along the longitudinal axis 4. During operation of the plunger pump 1, the groove 49 can cooperate with the projection 47 to allow the tappet 9 to reciprocate along the longitudinal axis 4 in the pump body 3, while limiting the rotation of the tappet 9 about the longitudinal axis 4 with respect to the pump body 3. It should be understood that the projection 47 may comprise any protruding feature capable of cooperating with the groove 49 of the tappet 9 to limit the rotation of the tappet 9 about the longitudinal axis 4 with respect to the pump body 3. It should also be understood that the recess 49 may be more than one recess and the projection 47 may be more than one projection cooperating with the more than one recess to define the rotation of the tappet 9 about the longitudinal axis 4 with respect to the pump body 3.

Fig. 5A and 5B show a portion of a plunger pump 1 "" according to yet another embodiment of the present application. Similar to the plunger pump 1 "'shown in fig. 4A and 4B, the first rotation limiting feature of the plunger pump 1"' is in the form of a groove 55 formed in the inner wall 37 of the pump body 3 and extending parallel to the longitudinal axis 4. In order to reduce friction between the second rotation limiting feature and the first rotation limiting feature, the present application proposes that the plunger pump 1 "" employs, as the second rotation limiting feature, a recess 51 and a guide ball 53 received in the recess 51, instead of the above-described protrusion 47. As shown in fig. 5A and 5B, a dimple 51 is formed in the outer circumferential surface 10 of the tappet body 9 opposite to the groove 55, and is sized to receive the guide ball 53. The guide ball 53 is received in the recess 51 and a portion thereof protrudes from the outer peripheral surface 10 and is received in the groove 55 so that the guide ball 53 can roll in the groove 55. During operation of the plunger pump 1, the guide balls 53 cooperate with the grooves 55 to allow the tappet 9 to reciprocate within the pump body 3 along the longitudinal axis 4, while limiting the rotation of the tappet 9 about the longitudinal axis 4 relative to the pump body 3. Using the dimple 51 and the guide ball 53 received in the dimple 51 as the second rotation limiting feature, as compared to using the protrusion 47 fixed to the tappet body 9, causes the friction between the second rotation limiting feature and the first rotation limiting feature to be converted from sliding friction to rolling friction, which reduces the system friction loss increased by the introduction of the rotation limiting feature, improves the transmission efficiency, and prolongs the component life.

It should be understood that the positions of the grooves and the guide balls and dimples may be interchanged. That is, a groove may be formed in outer circumferential surface 10 of tappet body 9 and extend parallel to longitudinal axis 4, and a dimple may be correspondingly formed in inner wall 37 of pump body 3. The guide balls are received in the pockets and a portion thereof protrudes from the inner wall 37 of the pump body 3 and is received in the groove, thereby allowing the tappet 9 to reciprocate within the pump body 3 along the longitudinal axis 4 and restricting rotation of the tappet 9 about the longitudinal axis 4 relative to the pump body 3. It should also be understood that the recess may be more than one recess and that the dimples and the guiding balls may be more than one set of dimples and guiding balls which cooperate with the more than one recess to define the rotation of the tappet 9 about the longitudinal axis 4 relative to the pump body 3.

The present invention has been described in detail with reference to the specific embodiments. It is clear that the embodiments described above and shown in the drawings are to be understood as illustrative and not as restrictive. It will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit of the invention, and these changes and modifications do not depart from the scope of the invention.

Claims (10)

1. A plunger pump comprising:

a pump body (3), the pump body (3) having an inner wall (37) and defining a longitudinal axis (4);

a plunger (5) arranged in the pump body (3) and extending along the longitudinal axis (4); and

a tappet assembly arranged in the pump body (3) and reciprocally movable along the longitudinal axis (4) to drive the plunger (5), the tappet assembly comprising a tappet (9), the tappet (9) having an outer peripheral surface (10) facing an inner wall (37) of the pump body (3);

characterized in that the pump body (3) has a first rotation limiting feature and the tappet (9) has a second rotation limiting feature, the first rotation limiting feature cooperating with the second rotation limiting feature to limit the rotation of the tappet (9) about the longitudinal axis (4) with respect to the pump body (3).

2. Plunger pump according to claim 1, characterized in that one of the first and second rotation limiting features is a protrusion (35, 35'), the other of the first and second rotation limiting features being a flat surface (33) extending parallel to the longitudinal axis (4).

3. Plunger pump according to claim 2, characterized in that the protrusions (35, 35') engage the flat surface (33) in a sliding friction or rolling friction manner when the tappet body (9) reciprocates along the longitudinal axis (4).

4. The plunger pump of claim 3, wherein:

the projection (35) is in the form of a guide pin extending parallel to the flat surface (33); or

The projection (35') is in the form of a guide roller which extends parallel to the flat surface (33) and can roll on the flat surface (33).

5. Plunger pump according to claim 2, characterised in that the projection (35, 35') protrudes from the inner wall (37) of the pump body (3) and the flat surface (33) is formed on the outer peripheral surface (10) of the tappet (9).

6. The plunger pump of claim 1, wherein one of the first and second rotation limiting features is a protrusion (35 ", 47), the other of the first and second rotation limiting features is a groove (43, 49, 55) extending along the longitudinal axis (4), the protrusion (35", 47) being received in the groove (43, 49, 55) to enable the protrusion (35 ", 47) to move relative to the groove (43, 49, 55) along the longitudinal axis (4).

7. Plunger pump according to claim 6, characterized in that the protrusions (35 ", 47) cooperate with the grooves (43, 49, 55) in a sliding friction or rolling friction manner when the tappet body (9) reciprocates along the longitudinal axis (4).

8. The plunger pump of claim 7, wherein:

the projection (35 ") is a guide bolt, one end (45) of the guide bolt (35") being received in the groove (43); or

The protrusion is part of a guide ball (53) received in a recess (51) and protruding from the recess (51), the guide ball (53) being able to roll in the groove (55).

9. Plunger pump according to claim 6, characterised in that the projection (35 ") projects from the inner wall 37 of the pump body (3) and the groove (43) is formed in the outer circumferential surface (10) of the tappet (9).

10. A high-pressure fuel pump comprising at least one high-pressure assembly for outputting high-pressure fuel, characterized in that the high-pressure assembly is constituted by a plunger pump according to any one of claims 1 to 9.

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