Shell for tappet and tappet

Abstract

The present invention relates to a housing for a tappet and a tappet. A housing for a tappet is disclosed, comprising a first section on a drive side and a second section on a driven side in an axial direction of the housing, wherein an outer diameter of the first section of the housing is smaller than an outer diameter of the second section, the first section and the second section are integrally formed, and the housing further comprises a torsion-resistant component extending radially outward from a side wall of the housing, the torsion-resistant component being formed by punching and bending from the side wall.

Description

Technical Field

[0001] This invention relates to the field of fuel supply. More specifically, this invention relates to tappets for fuel supply systems and housings for tappets. Background Technology

[0002] In a fuel supply system for an internal combustion engine, a high-pressure fuel pump injects fuel into the cylinder. Tappets are positioned between the plunger of the high-pressure fuel pump and the cam of the camshaft, with one axial end of the tappet inserted into a through-hole in the cylinder head. When the internal combustion engine starts, the camshaft rotates, and the cam drives the tappet to reciprocate within the through-hole of the cylinder head, simultaneously causing the plunger to reciprocate.

[0003] Figures 1 to 3 This illustrates a tappet structure. For example... Figures 1 to 3 As shown, the tappet includes a housing 110, a pin 120, a roller 130, and a rolling element 140. The housing 110 is generally cylindrical. The housing 110 has two opposing flat portions in its upper half (drive side). Both ends of the pin 120 are inserted into holes in the flat portions, and the pin 120 is fixed to the flat portions. The pin 120 rotatably supports the roller 130 via the rolling element 140, thereby rotatably mounting the roller 130 on the housing 110. The circumferential surface of the roller 130 is used to contact a cam (not shown) of the camshaft. To ensure that the roller 130 always maintains line contact with the cam, the tappet also includes an anti-torsion unit 150. The anti-torsion unit 150 includes a protrusion 151 and an insertion portion 152. An opening is provided in the side wall of the housing 110, and the anti-torsion unit 150 is partially inserted into the opening through the insertion portion 152. The protrusion 151 has an arcuate outer surface. The tappet is used to install into the through-hole of the cylinder head. A sliding groove is provided on the inner wall of the through-hole of the cylinder head. The protrusion 151 of the anti-torsion unit 150 can be inserted into the sliding groove. When the tappet reciprocates in the through-hole of the cylinder head, the protrusion 151 also reciprocates in the sliding groove, thereby preventing the tappet from rotating about its axis.

[0004] The housing 110 is disposed in the through hole with a contact fit and a very small tolerance range (e.g., only 0.008 μm). Therefore, the manufacturing precision requirements for this anti-torsion unit are very stringent, resulting in very high manufacturing costs. The separately configured anti-torsion unit needs to be assembled onto the housing through additional processes, which further extends the manufacturing time and increases the cost of the tappet.

[0005] Therefore, a simpler type of tappet is needed. Summary of the Invention

[0006] One object of the present invention is to provide a housing and tappets with a simple structure. Another object of the present invention is to provide a housing and tappets with reduced manufacturing costs.

[0007] One aspect of the present invention provides a housing for a tappet, comprising a first section located on a driving side along the axial direction of the housing and a second section located on a driven side, wherein the outer diameter of the first section of the housing is smaller than the outer diameter of the second section, the first section and the second section are integrally formed, and the housing further comprises an anti-torsion member extending radially outward from a sidewall of the housing, the anti-torsion member being formed from the sidewall by stamping and bending.

[0008] According to an embodiment of the present invention, the anti-torsion member extends from the first segment.

[0009] According to an embodiment of the present invention, an anti-torsion member is formed in the joint region between the first segment and the second segment.

[0010] According to an embodiment of the present invention, the wall thickness of the first segment is less than the wall thickness of the second segment.

[0011] According to an embodiment of the present invention, the anti-torsion member is bent at a 90-degree angle to the sidewall.

[0012] According to an embodiment of the present invention, the radial outer surface of the second segment is a ground surface, such that the radial outer surface of the second segment has a higher precision than the radial outer surface of the first segment.

[0013] According to an embodiment of the invention, the outermost edge of the anti-torsion member is at least partially in the shape of an outwardly projecting arc.

[0014] According to an embodiment of the present invention, the two corners of the outermost edge of the anti-torsion component are respectively arc-shaped.

[0015] According to an embodiment of the present invention, the outermost edge is arc-shaped in the middle portion between the two corners, and the radius of curvature of the middle portion is greater than the radius of curvature of the corners.

[0016] Another aspect of the present invention provides a tappet comprising: a housing according to an embodiment of the present invention; a pin fixed in a hole in a first section of the housing; and a roller having a cylindrical shape and rotatably disposed in the first section of the housing by means of the pin.

[0017] According to an embodiment of the present invention, the tappet further includes a plurality of rolling elements disposed between the pin and the rollers. Attached Figure Description

[0018] Figure 1 This is a perspective view of a roller tappet.

[0019] Figure 2 yes Figure 1 The cross-sectional view of the roller tappet is shown.

[0020] Figure 3 yes Figure 1 An exploded view of the roller tappet shown.

[0021] Figure 4 This is a perspective view of a housing for a tappet according to an embodiment of the present invention.

[0022] Figure 5 This is a partial cross-sectional view of a housing for a tappet according to an embodiment of the present invention.

[0023] Figure 6 This is a partially enlarged view of a housing for a tappet according to an embodiment of the present invention. Detailed Implementation

[0024] Hereinafter, embodiments of the invention are described with reference to the accompanying drawings. The following detailed description and drawings are provided to exemplify the principles of the invention, which is not limited to the described preferred embodiments; the scope of the invention is defined by the claims. The invention is now described in detail with reference to exemplary embodiments, some of which are illustrated in the accompanying drawings. The following description is made with reference to the accompanying drawings, and unless otherwise indicated, the same reference numerals in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all aspects of the invention. Rather, these embodiments are merely examples of systems and methods related to various aspects of the invention as covered in the appended claims.

[0025] Figure 4 This is a perspective view of a housing for a tappet according to an embodiment of the present invention. Figure 5 This is a partial cross-sectional view of a housing for a tappet according to an embodiment of the present invention. Figure 6 This is a partially enlarged view of a housing for a tappet according to an embodiment of the present invention.

[0026] like Figures 4 to 6 As shown, the tappet according to an embodiment of the present invention includes a housing 10, a pin, and a roller (not shown). The tappet according to the present invention can be applied to a fuel supply system and disposed between a cam of a camshaft and a plunger of a high-pressure fuel pump. The tappet can be disposed in a through-hole in a fuel supply system, such as a cylinder head, to reciprocate and drive the connected plunger to reciprocate.

[0027] The housing 10 is generally hollow cylindrical. The tappet can slide up and down in a through-hole, for example, in a cylinder head, via the sidewall of the housing 10. The housing 10 includes a first segment 11 located axially on the driving side (upper side) and a second segment 12 located axially on the driven side (lower side). In this invention, the driving side refers to the side where the tappet contacts the cam, while the driven side refers to the side where the tappet connects to the plunger. Viewed axially along the housing 10, the outer diameter of the first segment 11 is smaller than the outer diameter of the second segment 12. Therefore, the housing 10 is generally stepped cylindrical. The first segment 11 and the second segment 12 are integrally formed. In an exemplary embodiment, the wall thickness of the first segment 11 is smaller than the wall thickness of the second segment 12. According to some embodiments of the invention, viewed axially along the housing 10, the inner wall surface of the first segment 11 is flush with the inner wall surface of the second segment, and the outer wall surface of the first segment is located inside the outer wall surface of the second segment.

[0028] A pin can be fixed in the first section 11 of the housing 10. The housing 10 has holes 13 in the first section 11. In an exemplary embodiment, the housing 10 has two opposing flat portions 14 at the first section 11, and holes 13 are respectively provided on the flat portions 14. The pin can be inserted into the holes 13 through both ends and fixed to the housing 10, for example, by riveting. The flat portions 14 are recessed inward from the outer peripheral surface of the housing 10.

[0029] The roller has a cylindrical shape and is rotatably fitted onto the pin. Thus, the roller is rotatably disposed in the first section 11 of the housing 10. The roller is used to contact the cam of the camshaft. According to an embodiment of the invention, the tappet may further include a plurality of rolling elements, such as needle rollers, disposed between the inner surface of the roller and the outer surface of the pin. Therefore, the pin supports the roller in a rotatable manner by means of the rolling elements, thereby rotatably disposing the roller on the housing 10.

[0030] To ensure that the roller and cam maintain line contact at all times, the housing 10 also includes an anti-torsion member 15. The anti-torsion member 15 extends radially outward from the side wall of the housing 10. Specifically, the anti-torsion member 15 is a component integrally cantilevered from the side wall of the housing 10. The anti-torsion member 15 is formed from the side wall of the housing 10 by stamping and bending.

[0031] In an exemplary embodiment, the outermost edge of the anti-torsion member 15 is at least partially an outwardly projecting arc shape. According to certain embodiments of the invention, such as... Figure 4 and Figure 6As shown, the two corners of the outermost edge of the anti-torsion member 15 are respectively arc-shaped. In this case, the middle portion of the outermost edge of the anti-torsion member 15 between the two corners can be arc-shaped or straight. When the middle portion of the outermost edge between the two corners is arc-shaped, the radius of curvature of the middle portion can be different from the radius of curvature of the corners. For example, the radius of curvature of the middle portion can be greater than the radius of curvature of the corners. When the tappet is installed in a through hole, for example, in a cylinder head, the anti-torsion member is embedded in a sliding groove provided on the inner wall of the through hole in the cylinder head. The outermost edge of the anti-torsion member 15 is used to engage at least partially with the inner surface of the sliding groove. The sliding groove typically has an arc-shaped inner surface. When the outermost edge of the anti-torsion member 15 is at least partially arc-shaped (e.g., the corners are arc-shaped), the tappet including the anti-torsion member 15 according to an embodiment of the present invention can be directly installed on, for example, an existing cylinder head without modifying the structure of the cylinder head, etc. Therefore, the housing and tappet according to an embodiment of the present invention can have wider applicability.

[0032] In an exemplary embodiment, the anti-torsion member 15 is formed in the mating region between the first segment 11 and the second segment 12, i.e., the anti-torsion member 15 includes a portion from the first segment 11 and a portion from the second segment 12. The housing 10 is typically disposed in the through hole with a contact fit and is capable of sliding up and down. According to an embodiment of the invention, since the outer diameter of the first segment 11 is smaller than the outer diameter of the second segment 12, the housing 10 slides up and down in the through hole via the radial outer surface of the second segment 12, while the radial outer surface of the first segment 11 does not contact the inner surface of the through hole. Simultaneously, the anti-torsion member 15 is embedded in a sliding groove disposed on the inner surface of the through hole and slides up and down in the sliding groove as the housing 10 slides up and down in the through hole. The formation of the anti-torsion member 15 in the mating region between the first segment 11 and the second segment 12 can improve the fitting accuracy of the tappet and reduce friction and wear.

[0033] According to certain embodiments of the present invention, the radial outer surface of the second segment 12 is a ground surface, while the radial outer surface of the first segment 11 is an unground surface. Therefore, the radial outer surface of the second segment 12 can have a higher precision than the radial outer surface of the first segment 11. In the existing housing manufacturing process, the radial outer surface of the housing needs to be ground as a whole to meet dimensional and fitting accuracy requirements. According to embodiments of the present invention, since the housing 10 slides up and down in the through hole via the radial outer surface of the second segment 12 while the radial outer surface of the first segment 11 does not contact the inner surface of the through hole, the radial outer surface of the first segment 11 does not need to be ground. This reduces the machining accuracy requirements of the housing, while also reducing the manufacturing difficulty and cost of the housing.

[0034] In an exemplary embodiment, the anti-torsional member 15 extends from the first segment 11. For example... Figures 4 to 6 As shown, the root of the anti-torsion member 15 is located in the first segment 11. During the manufacturing process of the housing according to an embodiment of the present invention, to meet the precision requirements of the housing, the anti-torsion member 15 is first formed in the housing 10 by stamping and bending, and then the radial outer surface of the second segment 12 is ground. By extending the anti-torsion member 15 from the first segment 11, the grinding tool can avoid the anti-torsion member 15 during grinding and grind the second segment 12, thus not affecting the grinding process.

[0035] In an exemplary embodiment, the anti-torsion member 15 is bent at a 90-degree angle to the sidewall of the housing 10. This ensures that the anti-torsion member 15 and the second segment 12 do not overlap when viewed from the side, thereby preventing the anti-torsion member 15 from adversely affecting the grinding and sliding operations of the second segment 12. Simultaneously, the 90-degree angle between the anti-torsion member 15 and the sidewall of the housing 10 improves the fit accuracy of the tappet and reduces friction and wear.

[0036] According to certain embodiments of the present invention, the wall thickness of the first segment 11 is less than the wall thickness of the second segment 12, and the anti-torsion member 15 is formed in the joint region between the first segment 11 and the second segment 12 and extends from the first segment 11. Thus, the anti-torsion member 15 includes a first portion at its end and a second portion at its root, and the thickness of the first portion is greater than the thickness of the second portion. Therefore, since the anti-torsion member 15 has a greater thickness at its end, it can contact the sliding groove with a larger contact area, thereby improving the wear resistance of the anti-torsion member 15.

[0037] Although the invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the constructions and methods of the above embodiments. Rather, the invention is intended to cover various modifications and equivalent configurations. Furthermore, while various elements and method steps of the disclosed invention have been shown in various exemplary combinations and constructions, other combinations including more or fewer elements or methods also fall within the scope of the invention.

Claims

1. A housing for a tappet, comprising a first section located on a driving side along the axial direction of the housing and a second section located on a driven side, wherein, The outer diameter of the first segment of the housing is smaller than the outer diameter of the second segment. The inner wall surface of the first segment is flush with the inner wall surface of the second segment. The first segment and the second segment are integrally formed. The housing also includes an anti-torsion member extending radially outward from the side wall of the housing. The anti-torsion member is formed from the side wall by stamping and bending. The wall thickness of the first segment is smaller than the wall thickness of the second segment. The anti-torsion member is formed in the joint area between the first segment and the second segment and extends from the first segment. The anti-torsion member includes a portion from the first segment and a portion from the second segment.

2. The housing according to claim 1, wherein, The anti-torsion component is bent at a 90-degree angle to the sidewall.

3. The housing according to claim 1 or 2, wherein, The radial outer surface of the second segment is a ground surface, which gives the radial outer surface of the second segment a higher precision than the radial outer surface of the first segment.

4. The housing according to claim 1 or 2, wherein, The outermost edge of the anti-torsion component is at least partially in the shape of an outwardly protruding arc.

5. The housing according to claim 4, wherein, The two corners of the outermost edge of the anti-torsion component are respectively rounded.

6. The housing according to claim 5, wherein, The outermost edge is arc-shaped in the middle portion between the two corners, and the radius of curvature of the middle portion is greater than the radius of curvature of the corners.

7. A tappet, comprising: The housing according to any one of claims 1 to 6; A pin is fixed in a hole in the first section of the housing; and A roller, having a cylindrical shape, is rotatably disposed in the first section of the housing via the pin.

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