CN105805248B

CN105805248B - Mechanical tensioning device and movable rail thereof

Info

Publication number: CN105805248B
Application number: CN201410855845.9A
Authority: CN
Inventors: 刘琦盛; 蒂姆·亨切尔
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2014-12-31
Filing date: 2014-12-31
Publication date: 2020-02-21
Anticipated expiration: 2034-12-31
Also published as: CN105805248A

Abstract

The invention provides a mechanical tensioning device for a chain transmission system of an internal combustion engine and a movable rail. The base part is used for being placed against the chain so as to tension the chain, and a hook part for buckling the plate spring is arranged on the inner surface of the base part. An opening is formed in the outer surface of the base part corresponding to the hook part, and the opening is used for demolding when a mold is used for forming the accommodating space below the hook part. Therefore, the number of dies used in the forming process of the movable rail can be reduced, and the manufacturing cost of the movable rail is favorably reduced.

Description

Mechanical tensioning device and movable rail thereof

Technical Field

The present invention relates to mechanical tensioning devices, and more particularly to mechanical tensioning devices for chain drive systems of internal combustion engines. The invention also relates to a movable rail of the mechanical tensioning device.

Background

In order to ensure that a chain in a chain drive system for an internal combustion engine is in tension from time to time, a mechanical tensioning device is provided. Fig. 1 and 2 show a conventional mechanical tensioner of the prior art, in which a leaf spring 2' is used. The mechanical tensioning device comprises a movable rail 1 'and a plate spring 2'. The movable rail 1 'comprises a base part 5' and oppositely arranged side walls 3 'on both sides of the base part 5', said base part 5 'being placed against the chain for tensioning the chain, the inner sides of the side walls 3' being provided with hooks 31 ', which hooks 31' snap said leaf spring 2 'after mounting of the leaf spring 2', thereby preventing the leaf spring 2 'from disengaging from the underside of the hooks 31'.

Fig. 3 and 4 show the forming process of the movable rail 1 ' of the above-mentioned mechanical tensioner, since the hook portion 31 ' extends upward from the base portion and has a protrusion extending inward, at least three dies are required in the forming process to form the basic structure of the movable rail 1 '. Wherein the mold 8 'is used to form the outer contour of the movable rail 1', the mold 7 'is used to form the inner structure of the movable rail 1' and the outer structure of the hook portion 31 ', and the mold 9' is used to form the lower structure of the hook portion 31 'and can be smoothly separated from the inner portion of the movable rail 1'.

Since the running rail 1' requires a plurality of molds for molding, this clearly increases the complexity of the production and thus increases the costs.

Disclosure of Invention

It is therefore an object of the present invention to provide an improved mechanical tensioner and running rail for a chain drive system of an internal combustion engine, which is manufactured at a lower cost.

In order to solve the above problems, the present invention provides a movable rail for a mechanical tensioner of a chain drive system of an internal combustion engine, the movable rail including a base portion and side walls located at both sides of the base portion and disposed oppositely, the base portion being configured to be placed against a chain to tension the chain, a hook portion configured to engage a plate spring being provided on an inner surface of the base portion, an opening being provided on an outer surface of the base portion at a position corresponding to the hook portion, the opening being configured to release a mold when a receiving space below the hook portion is formed.

Compared with the prior art, the technical scheme of the invention has the following advantages: the outer surface of the base part is provided with an opening corresponding to the hook part, and the opening is used for demolding when a mold is used for forming the accommodating space below the hook part, so that the number of the molds used in the forming process of the movable rail can be reduced, and the manufacturing cost of the movable rail is favorably reduced.

To solve the above problems, the present invention also provides a mechanical tensioner for a chain drive system of an internal combustion engine, the mechanical tensioner comprising an elongated leaf spring, a pivot rod fixed to the internal combustion engine, a moving rail defining a base portion and a side wall, and a pin positioned on the internal combustion engine, the base portion of the moving rail being placed against the chain for guiding the travel of the chain, and the moving rail being pivotably connected to the pivot rod so as to be rotatable about the pivot rod, the base portion of the moving rail being provided with a hook portion, one end of the leaf spring abutting on the pin, the other end of the leaf spring engaging with the hook portion, and the leaf spring being arranged to press against the moving rail to apply pressure to the moving rail, the outer surface of the base portion being provided with an opening corresponding to the hook portion for demolding of a mold when forming a housing space below the hook portion.

Compared with the prior art, the technical scheme of the invention has the following advantages: the outer surface of the base part is provided with an opening corresponding to the hook part, and the opening is used for demolding when a mold is used for forming the accommodating space below the hook part, so that the number of the molds used in the movable rail forming process can be reduced, and the manufacturing cost of the mechanical tensioning device is favorably reduced.

Drawings

The features of the present invention and its advantages will be apparent from the following detailed description of embodiments of the invention with reference to the accompanying drawings. In the figure:

fig. 1 is a schematic view of a prior art mechanical tensioner employing a leaf spring.

Fig. 2 is a partial schematic view of the mechanical tensioner shown in fig. 1.

Fig. 3 is a schematic view of the mechanical tensioner of fig. 1 with the movable rail formed by a die.

Fig. 4 is a partial schematic view of the mechanical tensioner of fig. 1 with the movable rail formed by a die.

Fig. 5 is a partial schematic view of the moving rail of the mechanical tensioner of the present invention.

Fig. 6 is a partial cross-sectional view of the moving rail of the mechanical tensioner of the present invention.

Fig. 7 is a schematic view of the molding of the movable rail of the mechanical tensioner of the present invention through a mold.

Fig. 8 is a partial schematic view of the die-forming of the movable rail of the mechanical tensioner of the present invention.

Fig. 9 is another partial schematic view of the die-forming of the movable rail of the mechanical tensioner of the present invention.

Fig. 10 is a schematic view of the mechanical tensioner of the present invention as assembled on a chain.

Detailed Description

As shown in fig. 10, the chain drive system of the internal combustion engine includes a chain 100 and a sprocket 200. The mechanical tensioner according to the present invention comprises a pivot rod 300 fixed to the internal combustion engine, a movable rail 1 and a pin 400 positioned on the internal combustion engine, the movable rail 1 being placed against the chain 100 for guiding the travel of the chain 100. The moving rail 1 has a boss with a through hole for the pivot rod 300 to pass through, so that the moving rail 1 is pivotally connected to the pivot rod 300 to be rotatable around the pivot rod 300. The mechanical tensioning device further comprises an elongated leaf spring 2, one end of which is in contact with the pin 400 and rests on the pin 400, a hook 31 (see fig. 5-6) being provided on the moving rail 1, the other end of the leaf spring 2 engaging the hook 31, thereby locking the leaf spring 2 on the moving rail 1, wherein the leaf spring 2 is pre-tensioned to suitably apply a pressure to the moving rail 1, thereby keeping the chain 100 sufficiently tensioned.

By adjusting the pretension of the leaf spring 2, a pressure is suitably applied to the moving rail 1. By means of the pressure of the pretensioned leaf spring 2, the running rail 1 can be rotated about a pivot lever 300 which is fixed in the internal combustion engine. In this way, the mechanical tensioning device of the present invention will ensure that the chain 100 is in tension as the chain travels, regardless of whether the chain is loose or tight.

As shown in fig. 5 and 6, the movable rail 1 includes a base 5 and side walls 3 disposed opposite to each other on both sides of the base 5. The outer surface of the base 5 is placed against the chain 100 in order to tension the chain 100. The hook 31 is located on the inner surface of the base 5, in the embodiment, the hook 31 is spaced apart from the side wall 3, and the side wall 3 is notched at the corresponding position of the hook 31, and a gap exists between the hook 31 and the notch. When the plate spring 2 is assembled, one end of the plate spring is pressed below the hook portion 31, and in this process, the hook portion 31 can move to the side of the notch, which can reduce the friction force with the hook portion 31 during the installation of the plate spring 2. Of course, in other embodiments, the hook 31 may be integrally formed directly with the side wall 3 without providing a notch.

As described above, the hook 31 needs to be pressed on the upper side of the plate spring 2, and therefore the hook 31 has the inwardly extending projection 310. As described in the background art, in order to mold the protrusion 310 during the molding of the movable rail 1, a separate mold is required to be provided below the protrusion 310 so as to form a receiving space (not numbered) for engaging with the plate spring 2. In order to facilitate the molding of the movable rail 1, the opening 50 is provided on the outer surface of the base part 5 at a position corresponding to the hook part 31, and the opening 50 penetrates through the base part 5 and corresponds to the protrusion part 310 of the hook part 31 in a direction perpendicular to the base part 5. In this embodiment, the opening 50 has a rectangular shape in cross section.

As shown in fig. 7 to 9, the movable rail 1 of the present invention requires only two

molds

7 and 8 for molding. Wherein the first mold 7 is used to form the structure between the side walls 3 and may form the upper structure of the hook 31. The second mold 8 is used to form the outer structure of the base 5, and two cylindrical bodies b are provided on the second mold 8. During the molding of the movable rail 1, the cylindrical body b corresponds to the opening 50 on the base 5 and passes through the opening 50 to the lower side of the protrusion 310. In this way, the second mold 8 can form not only the external structure of the base 5 but also the housing space below the protruding portion 310. Importantly, the second mold 8 can also be smoothly released during the molding process of the movable rail 1, which obviously contributes to reducing the manufacturing cost of the movable rail 1. Of course, the above molding process is only a simple description made in conjunction with the present invention, and the core of the present invention is to reduce the third mold for forming the receiving space under the protrusion 310 in the prior molding method.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A running rail for a mechanical tensioner for a chain drive system of an internal combustion engine, said running rail comprising a base portion and oppositely disposed side walls on either side of the base portion, said base portion being adapted to be placed against a chain to tension the chain, a hook portion being provided on the inner surface of the base portion for engaging a leaf spring, characterized in that: an opening is formed in the outer surface of the base part corresponding to the hook part, and the opening is used for demolding when a mold is used for forming the accommodating space below the hook part.

2. A moving rail according to claim 1, characterized in that: the cross section of the opening is rectangular.

3. A moving rail according to claim 1, characterized in that: the hook part and the side wall are arranged at intervals, the side wall is cut at the corresponding position of the hook part, and a gap exists between the hook part and the cut.

4. A moving rail according to claim 1, characterized in that: the hook part and the side wall are integrally formed.

5. A mechanical tensioner for a chain drive system of an internal combustion engine, the mechanical tensioner comprising an elongated leaf spring, a pivot rod fixed to the internal combustion engine, a moving rail defining a base portion and a side wall, the base portion of the moving rail being placed against the chain for guiding the travel of the chain, and the moving rail being pivotably connected to the pivot rod so as to be rotatable about the pivot rod, the moving rail being provided with a hook portion on its base portion, the leaf spring resting with one end on the pin and the other end engaging the hook portion, and the leaf spring being arranged to press against the moving rail to apply a pressing force to the moving rail, characterized in that: an opening is formed in the outer surface of the base part corresponding to the hook part, and the opening is used for demolding when a mold is used for forming the accommodating space below the hook part.

6. The mechanical tensioner as in claim 5, wherein: the hook part extends inwards to form a protruding part, and the accommodating space is located between the protruding part and the base part.

7. The mechanical tensioner as in claim 5, wherein: the hook part and the side wall are arranged at intervals, the side wall is cut at the corresponding position of the hook part, and a gap exists between the hook part and the cut.