ROLLER DEVICE, PIN FOR USE IN A ROLLER DEVICE AND METHOD FOR LOCKING A PIN

Abstract

 The invention relates to a roller device including a pin (10), a roller (12) supported by said pin (10) and tappet (14) configured to support said pin (10) in supporting bores (14d, 14e) provided in lateral flanges (14b, 14c) of said tappet (14), wherein at least one end face of said pin (10) is configured to be plastically deformed using a caulking tool 16 in order to lock said pin (10) within the pertinent bore (14d, 14e).
It is proposed that said at least one end face is of the pin (10) is provided with a recess (10c, 10d) configured to facilitate said plastic deformation.

Description

Field of the Invention

[0001] The invention relates to a roller device such as a cam follower or rocker arm bearing roller, for pin for use in a roller device and to a method for locking a pin.

Background of the Invention

[0002] The document EP 2607637 A1 discloses a mechanical system comprising a support element which includes two bores in lateral flanges of a tappet, a pin which is fitted in the two bores and comprises two opposite ends, each adapted to be caulked in one of the two bores, and a roller element which is positioned between the two bores along its rotation axis and is movable in rotation relative to the pin around the rotation axis.

[0003] The system of EP 2607637 A1 is characterized in that at least one bore comprises at least one radial recess which extends from the bore along a radial direction relative to the rotation axis and is adapted to receive a plastically deformed radial portion of the caulked end of the pin.

[0004] The caulking load required to plastically deform the ends of a pin is high, in particular in the case of through-hardened pins. The high caulking load results in wear of the caulking tool, increases the risk of producing cracks, requires heavy and expensive machines and should therefore be avoided.

[0005] In order to solve these problems, it has been proposed to use a sharp caulking tool producing a circular caulking mark close to the outer circumference of the axial end face of the pin such that only the radially outer part of the end face is plastically deformed. The caulking tool deforms the pin and presses the material radially outward to achieve an axial locking.

Summary of the Invention

[0006] The invention seeks to provide a roller device requiring a reasonable caulking force.

[0007] The invention relates to a roller device including a pin, a roller supported by said pin and a tappet configured to support said pin in supporting bores provided in lateral flanges of said tappet, wherein at least one end face of said pin is configured to be plastically deformed using a caulking tool in order to lock said pin within the pertinent bore.

[0008] It is proposed that said at least one end face is of the pin provided with a recess configured to facilitate said plastic deformation. In the context of the invention, the recess shall be construed as a recess other than a central bore as used e.g. for holding the pin in a process of induction hardening.

[0009] The new pin design according to the invention allows for a reduction of a caulking load, to optimize the caulking resistance, in particular in case of through hardened pin.

[0010] The roller device according to the invention may in particular be a cam follower unit, a roller for a rocker arm bearing a roller for use in a fuel injection pump of an internal combustion engine.

[0011] In the context of the invention, the locking of the pin preferably refers to an axial immobilization of the pin with respect to the tappet, but may further entail an immobilization in the rotation direction as well. Alternatively, the locking may refer to a relative axial immobilization of the pin in such a way that after caulking an axial clearance remains between the pin and the tappet, in the so-called and well know free-floating pin configuration.

[0012] Preferably, the recess has a limited depth. This means in particular that the recess is not formed as an axial through-hole. Further, it is proposed that the recess exists in the configuration of the pin prior to the plastic deformation.

[0013] In a preferred embodiment of the invention, the recess has a limited depth smaller than or equal to a width of the lateral flange accommodating said end face.

[0014] According to one embodiment of the invention, the recess has a cylindrical shape. The cylindrical recess can be easily manufactured and the caulking load can precisely be set by adjusting the width of the side wall surrounding the recess.

[0015] According to one embodiment of the invention, it is proposed that the recess has a spherical shape or a conical shape. This results in a decreasing width of the side wall side wall surrounding the recess with advantages for the caulking process including avoidance of cracks and robustness against tolerances.

[0016] The advantages of the invention are of particular relevance in cases where the pin is formed as a through-hardened pin because the prior art requires a particularly important caulking load in this case.

[0017] In alternative embodiments of the invention, the pin may be formed as an induction-hardened pin.

[0018] According to a further aspect of the invention, it is proposed that the recess is surrounded by a wall designed to be deformed radially outward with said caulking tool, wherein a width of said wall is equal or less than 25% of a diameter of said pin.

[0019] The pin according to the invention may or may not be provided with a central bore, wherein the recess may be arranged coaxial to said bore in the former case.

[0020] A further aspect of the invention relates to a pin for use in a roller device as described above, wherein at least one end face is of the pin provided with a recess configured to facilitate said plastic deformation.

[0021] A further aspect of the invention relates to a roller device including a pin, a roller supported by said pin and tappet configured to support said pin in supporting bores provided in lateral flanges of said tappet, wherein said pin is obtained by plastically deforming a pin as described above using a caulking tool in order to lock said pin within the pertinent bore.

[0022] A further aspect of the invention relates to a method for locking a pin supporting a roller in a bore of a tappet. The method includes the steps of providing a pin with a recess configured to facilitate a plastic deformation; inserting the pin having the recess into the bore; and locking the pin within the bore by plastically deforming the material surrounding the recess radially outward using a caulking tool.

[0023] The above embodiments of the invention as well as the appended claims and figures show multiple characterizing features of the invention in specific combinations. The skilled person will easily be able to consider further combinations or sub-combinations of these features in order to adapt the invention as defined in the claims to his specific needs.

Brief Description of the Figures

[0024] 

Fig. 1

is a sectional view of a roller device according to the invention prior to caulking;

Fig. 2

is a sectional view of a roller device according to Fig. 1 after caulking;

Fig. 3

is the roller device according to Fig. 2 in its final configuration ready for use;

Fig. 4

is a sectional view of a pin of a roller device according to a second embodiment of the invention with a spherical recess; and

Fig. 5

is a sectional view of a pin of a roller device according to a third embodiment of the invention with a conical recess.

Detailed Description of the Embodiments

[0025] Fig. 1 is a sectional view of a roller device according to the invention. The roller device includes a through-hardened pin 10, a roller 12 supported by said pin 10 and a tappet 14. The tappet 14 has a cylindrical base portion 14a configured to receive a tappet rod (not illustrated) and to reciprocate within a guiding bore. The roller 12 is supported on the pin 10 in a rotatable manner. To this end, the pin 10 may be provided with a coating or the roller 12 may be supported by a needle bearing or a bushing. Two axially protruding flanges 14b, 14c are provided opposite to the side of the base portion 14a receiving the tappet rod. The flanges 14b, 14c are configured to support the pin 10 in supporting bores 14d, 14e.

[0026] In the configuration for the intended use in a combustion machine, both axial end faces of the pin 10 plastically deformed using a caulking tool 16 (Fig. 2) in order to lock the pin 10 within the pertinent bore 14d, 14e.

[0027] In order to facilitate the caulking, the end faces 10a, 10b of the pin 10 are provided with a recess 10c, 10d, respectively, in addition to a bore 10f formed as a through hole. The recess 10c, 10d has a limited depth d1 smaller than or equal to a width w1 of the lateral flange 14b, 14c accommodating the end of the pin 10.

[0028] The roller device according to the invention may in particular be a cam follower unit, a roller 12 for a rocker arm bearing or a roller 12 for use in a fuel injection pump of an internal combustion engine.

[0029] In the embodiment of Fig. 1, the recess 10c, 10d has a cylindrical shape. The wall 10g, 10h surrounding the recess 10c, 10d designed to be deformed radially outward with the caulking tool 16 has a width W equal or less than 25 % of a diameter of the pin 10.

[0030] Fig. 2 is a sectional view of a roller device according to Fig. 1 after caulking with conical caulking tools 16 still being inserted from both sides. The caulking tools 16 are pressed into the recess 10c, 10d in an axial direction with a caulking load F, respectively, such that the conical outer surface of the tool 16 abuts to the radially outer walls 10g, 10h of the recess 10c, 10d and deforms the walls 10g, 10h in a radially outward direction until the pin 10 is securely immobilized within the bores 14d, 14e of the flanges 14b, 14c. A part of the material of the pin 10 is squeezed over the axially outermost edges of the bores 14d, 14e to form a brim 10i such that the diameter in the end parts of the bores 14d, 14e exceeds the diameter of the bore 14d, 14e.

[0031] Though Fig. 2 illustrates an embodiment where caulking tools 16 are inserted from both sides, it goes without saying that alternative embodiments where the pin 10 is caulked only from one side are possible. In this case, the pin 10 may have an extended head portion on an end face opposite to the end face provided with the recess 10c, 10d.

[0032] The amount of deformation is illustrated in an exaggerated manner. The pin 10 need not protrude axially over the lateral side faces of the flanges 14b, 14c and the deformation may be such that the material of the pin 10 is only pressed against the inner circumferential surfaces of the bore.

[0033] Fig. 3 illustrates the roller device in its configuration ready for use with the caulking tools 16 removed. The negative shape of the conical caulking tools 16 is impressed in the walls 10g, 10h of the recesses 10c, 10d, the bottom surface of which remains essentially undeformed.

[0034] The sequence of Figs. 1 to 3 illustrates a method for locking a pin 10 supporting a roller 12 in a bore 14d, 14e of a tappet 14. The method includes the steps of providing a pin 10 with a recess 10c, 10d configured to facilitate a plastic deformation, inserting the pin 10 having the recess 10c, 10d into the bore; and locking the pin 10 within the bore 14d, 14e by plastically deforming the material surrounding the recess 10c, 10d radially outward using a caulking tool 16.

[0035] Fig. 4 is a sectional view of a pin 10 of a roller device according to a second embodiment of the invention with a spherical recess 10c, 10d; and Fig. 5 is a sectional view of a pin 10 of a roller device according to a third embodiment of the invention with a conical recess 10c, 10d. The caulking tools for use in combination with the pins 10 of Figs. 3 and 4 are not illustrated but may be adapted to the shape of the recess 10c, 10d.

[0036] In all illustrated embodiments, the locking of the pin with respect to the tappet results in a immobilization of the pin, axially and optionally in the rotation direction.
Alternatively, the locking may refer to a relative axial immobilization of the pin in such a way that after caulking an axial clearance remains between the pin and the tappet, in the so-called and well know free-floating pin configuration.

Claims

1. Roller device including a pin (10), a roller (12) supported by said pin (10) and a tappet (14) configured to support said pin (10) in supporting bores (14d, 14e) provided in lateral flanges (14b, 14c) of said tappet (14), wherein at least one end face of said pin (10) is configured to be plastically deformed using a caulking tool 16 in order to lock said pin (10) within the pertinent bore (14d, 14e),
characterized in that said at least one end face is of the pin (10) is provided with a recess (10c, 10d) configured to facilitate said plastic deformation.

2. Roller device according to claim 1,
characterized in that said recess (10c, 10d) has a limited depth (d1) and that the recess (10c, 10d) exists in the configuration of the pin (10) prior to the plastic deformation.

3. Roller device according to claim 1 or 2,
characterized in that said recess (10c, 10d) has a limited depth (d1) smaller than or equal to a width (w1) of the lateral flange (14b, 14c) accommodating said end face.

4. Roller device according to one of the preceding claims, characterized in that the recess (10c, 10d) has a cylindrical shape.

5. Roller device according to one claims 1-3, characterized in that the recess (10c, 10d) has a spherical shape.

6. Roller device according to one claims 1-3, characterized in that the recess (10c, 10d) has a conical shape.

7. Roller device according to one of the preceding claims, characterized in that the pin (10) is formed as a through-hardened pin (10).

8. Roller device according to one of claims 1-6, characterized in that the pin (10) is formed as an induction-hardened pin (10).

9. Roller device according to one of the preceding claims, characterized in that the recess (10c, 10d) is surrounded by a wall (10g, 10h) designed to be deformed radially outward with said caulking tool (16), wherein a width (W) of said wall (10g, 10h) is equal or less than 25% of a diameter (D) of said pin (10).

10. Roller device according to one of the preceding claims, characterized in that the pin (10) is provided with a central bore (10f), wherein the recess (10c, 10d) is arranged coaxial to said bore (10f).

11. Roller device according to any preceding claim, characterized in that the pin is immobilized axially in the tappet.

12. Roller device according to any preceding claim, characterized in that an axial clearance remains between the pin and the tappet, in the so-called and well know free-floating pin configuration.

13. Pin for use in a roller device according to one of claims 1 to 12, characterized in that at least one end face is of the pin (10) provided with a recess (10c, 10d) configured to facilitate said plastic deformation.

14. Roller device including a pin (10), a roller (12) supported by said pin (10) and a tappet (14) configured to support said pin (10) in supporting bores (14d, 14e) provided in lateral flanges (14b, 14c) of said tappet (14), wherein said pin (10) is obtained by plastically deforming a pin (10) according to claim 11 using a caulking tool (16) in order to lock said pin (10) within the pertinent bore (14d, 14e).

15. Method for blocking a pin (10) supporting a roller (12) in a bore (14d, 14e) of a tappet (14), characterized by including, in the sequence as follows, the steps of:

a. providing a pin (10) with a recess (10c, 10d) configured to facilitate a plastic deformation;

b. inserting the pin (10) having the recess (10c, 10d) into the bore (14d, 14e); and

c. locking the pin (10) within the bore (14d, 14e) by plastically deforming the material surrounding the recess (10c, 10d) radially outward using a caulking tool (16).

Drawing