COLUMNAR HYDRAULIC TAPPET

Abstract

A columnar-type hydraulic tappet, provided with a housing, a plunger moving axially with respect to the housing being mounted in an inner cavity of the housing, a high pressure cavity used for a hydraulic medium extending between a lower end surface of the plunger and a lower side of the housing, a first ring groove being arranged below a head portion of the plunger, a second ring groove being arranged at a central portion of the plunger, a plunger central wall being between the first ring groove and the second ring groove, the second ring groove being a concave wide ring groove, wherein at least one plunger oil inlet hole being arranged on the plunger concave wide ring groove or the plunger central wall, a bottom portion edge of the plunger oil inlet hole containing flanging facing towards an inner cavity of the plunger.

Claims

1. A columnar-type hydraulic tappet, provided with a housing, a plunger moving axially with respect to the housing being mounted in an inner cavity of the housing, a high pressure cavity used for a hydraulic medium extending between a lower end surface of the plunger and a lower side of the housing, the high pressure cavity being sealed by a unidirectional valve opened towards the high pressure cavity, an outer ring groove used for hydraulic medium circulation being arranged on the outer diameter of the housing, an inner ring groove used for hydraulic medium circulation being arranged at a radial inner side of the housing, one or a plurality of oil inlet holes being arranged between the inner ring groove and the outer ring groove, a first ring groove being arranged below a head portion of the plunger, a second ring groove being arranged at a central portion of the plunger, a plunger central wall being between the first ring groove and the second ring groove, the second ring groove being a concave wide ring groove, wherein at least one plunger oil inlet hole being arranged on the plunger concave wide ring groove or the plunger central wall, a bottom portion edge of the plunger oil inlet hole containing flanging facing towards an inner cavity of the plunger.

2. The columnar-type hydraulic tappet according to claim 1, wherein the flanging of the plunger oil inlet hole is a non-fractured window-opening structure, and a flanging that is naturally formed by the processing of plunger oil inlet hole is attached to the bottom of oil inlet hole of the inner cavity of the plunger.

3. The columnar-type hydraulic tappet according to claim 2, wherein the plunger oil inlet hole has a unilateral window opening, and the flanging is located on one side of the oil inlet hole of the plunger inner wall.

4. The columnar-type hydraulic tappet according to claim 2, wherein the plunger oil inlet hole has a bilateral window opening, and the flanging is located on both sides of the oil inlet hole of the plunger inner wall.

5. The columnar-type hydraulic tappet according to claim 1, wherein the plunger oil inlet hole is in a cone shape, and the plunger is provided with a surrounding flanging connected to the plunger body at the bottom of the plunger oil inlet hole.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 is a schematic view of a hydraulic tappet according to the specific embodiment 1 of the present invention.

[0024] FIG. 2 is a schematic view of a plunger according to the specific embodiment 1 of the present invention.

[0025] FIG. 3 is a schematic view of a plunger according to the specific embodiment 2 of the present invention.

[0026] FIG. 4 is a schematic view of a plunger according to the specific embodiment 3 of the present invention.

[0027] FIG. 5 is a schematic view of a plunger according to the specific embodiment 4 of the present invention.

[0028] Notes:

[0029] 1. Plunger

[0030] 2. Housing

[0031] 3. Unidirectional valve

[0032] 4. Reset spring

[0033] 5. Plunger concave wide ring groove

[0034] 6. Upper conical surface of plunger ring groove

[0035] 7. Plunger oil inlet hole

[0036] 8. Flanging of plunger oil inlet hole

[0037] 9. Oil hole of housing

[0038] 10. Inner ring groove of housing

[0039] 11. Oil chamber

[0040] 12. High pressure cavity

[0041] 13. Plunger head portion

[0042] 14. Outer ring groove of housing

[0043] 15. Plunger neck portion (first ring groove)

[0044] 16. Grinding wheel groove of housing

[0045] 17. Plunger upper wall

[0046] 18. First inner cylindrical wall of housing

[0047] 19. Second inner cylindrical wall of housing

[0048] 20. Limit snap spring

[0049] 21. Seal belt

DETAILED DESCRIPTION

[0050] The present invention is further described in combination with drawings.

EXAMPLE 1

[0051] Referring to FIG. 1, a columnar-type hydraulic tappet used for an engine valve mechanism, provided with a tank-shaped housing (2), a plunger (1) moving axially with respect to the housing being mounted in an inner cavity of the housing (2), a high pressure cavity (12) being between a lower end surface of the plunger (1) and the housing (2), the high pressure cavity (12) being sealed by a unidirectional valve (3) at the lower end of the plunger (1), and a reset spring(4) that connects the plunger (1) and the housing (2) being in the high pressure cavity (12). An outer ring groove of housing (14) used for hydraulic medium circulation being arranged on the outer diameter of the housing (2), an inner ring groove of housing (10) used for hydraulic medium circulation being arranged at a radial inner side of the housing, one or a plurality of oil holes (9) being arranged between the inner ring groove of housing (10) and the outer ring groove of housing (14), a first inner cylindrical wall of housing (18) being arranged at the upper inner wall of the inner ring groove of housing (10) and a second inner cylindrical wall of housing (19) being arranged at the lower inner wall of the inner ring groove of housing (10), a grinding wheel groove (16) used for blindhole processing being arranged at the lower end of the second inner cylindrical wall of housing (19). A concave wide ring groove (5) used for hydraulic medium circulation is arranged at the outer diameter of the plunger (1), the plunger wall above the concave wide ring groove (5) is a plunger upper wall (17), and the surface that connects the plunger concave wide ring groove (5) and the plunger upper wall (17) is an upper conical surface of plunger ring groove (6). One or a plurality of plunger oil inlet hole (7) distributed circumferentially are arranged on the plunger concave wide ring groove (5) or plunger upper wall (17), and there is a flanging (8) naturally formed by hole processing at the circumference of the plunger oil inlet hole (7). The plunger concave wide ring groove (5) is connected with the plunger oil inlet hole (7). The hydraulic medium enters to the plunger oil chamber (11) from the outer ring groove of housing (14). A limit snap spring (20) is arranged between the plunger concave wide ring groove (5) and the inner ring groove of housing (10). A concave neck portion (15) is arranged at the lower end of the head portion (13) of the plunger (1), i.e. a first ring groove. The role of the neck portion (15) is to facilitate the installation of the card, through the reliable connection between the card and the roller rocker arm, it can prevent falling off.

[0052] Referring to FIG. 2, the plunger (1) is an integral structure, with the features of simple structure, excellent processing technology and convenience for assembly.

[0053] The plunger oil inlet hole (7a) is processed by a punch forming process in which the metal material flows into the cavity of the plunger to form a flanging of plunger oil inlet hole (8a). The process is simple, without generating wastes.

[0054] The plunger oil inlet hole (7a) is a bilateral “window-opening” structure, and the directions of window-opening are not limited to the vertical direction, which may include horizontal window-opening or double-sided window opening of other directions. The wall of window-opening hole may be a curved surface, not limited to a plane.

[0055] The plunger oil inlet hole (7a) is located on the plunger concave channel groove (5) or on the plunger upper wall (17), which should ensure that the width of the seal belt (14) formed by the upper boundary of the plunger oil inlet hole (7) and the first inner cylindrical wall of housing (18) is greater than 0.5 mm and the lower boundary of the plunger oil inlet hole (7a) is lower than the upper boundary of the upper conical surface of plunger ring groove (6).

EXAMPLE 2

[0056] Referring to FIG. 3, the difference from Example 1 is that, the plunger oil inlet hole (7b) is a unilateral window opening structure and the window-opening faces upwards.

EXAMPLE 3

[0057] Referring to FIG. 4, the difference from Example 1 is that, the plunger oil inlet hole (7c) is a unilateral window opening and the window-opening faces downwards.

EXAMPLE 4

[0058] Referring to FIG. 5, the difference from Example 1 is that, the plunger oil inlet hole (7d) is a unilateral window opening and the window-opening faces towards left or right direction.

EXAMPLE 5

[0059] Referring to FIG. 5, the difference from Example 1 is that, the plunger oil inlet hole (7e) is a conical structure, and the flanging of plunger oil inlet hole (8e) is naturally formed around the entire circumference of the plunger oil inlet hole (7e).

[0060] The above-described embodiments preferably adopt a bilateral window opening structure, which has the advantages of symmetrical force and long life of the molds compared with the unilateral window opening; in addition, its window-opening flow area is larger provided that the cross-sectional area of the mold is the same. Compared with a cone-shaped window-opening, it has a larger window-opening flow area provided that the cross-sectional area of the mold is the same.