JPH0747634Y2 - Belt tension adjustment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] This invention adjusts the tension of a power transmission belt used in an engine, and more particularly, adjusts the tension of a timing belt for transmitting power of an engine crankshaft in an automobile. Regarding the device.

[Conventional technology]

For example, in an automobile engine, a tension adjusting device that prevents looseness of a toothed timing belt that is stretched between a crankshaft pulley and a camshaft pulley is as shown in FIGS. 5 and 6. A pulley arm 4 that is provided with a tension pulley 2 that engages with a belt 1 that transmits engine power, and is swingable around a fulcrum shaft 3, and an auto tensioner 5 that presses the pulley arm 4 against the tension side of the belt 1. The tip of the lid 6 of the auto tensioner 5 is in contact with the pulley arm 4.

In the structure of the tip of the rod 6 and the rod contact portion of the pulley arm 4 in the conventional tension adjusting device, as shown in FIG. 5, the tip of the rod 6 is formed into a spherical surface 7 and the contact surface 8 of the pulley arm 4 is formed. It is formed in a plane and absorbs the contact angle with the pulley arm 4 accompanying the swinging of the tension pulley 2 about the fulcrum shaft 3.

Since the rod 6 and the pulley arm 4 are in point contact with the spherical surface 7 on the plane, the contact surface 8 side of the pulley arm 4 is induction hardened to prevent abrasion.

Further, as shown in FIG. 6, the tip of the rod 6 is formed into a spherical surface 7, and the cylindrical quenching material 9 is press-fitted in the rod axial direction into the rod abutting portion of the pulley arm 4 formed using a light alloy. A structure in which the spherical surface 7 of the rod 6 is brought into contact with the end surface of the quenched material 9 has been proposed.

[Problems to be solved by the device]

By the way, in the former tension adjusting device shown in FIG. 5, since the quenching hardness of the pulley arm 4 is limited, the occurrence of wear is unavoidable, and these pulley arms 4 are high-frequency hardened due to induction hardening. It is necessary to use a special material, and even if such a material is used, it is difficult to maintain a hardness of H _RC 55 or higher stably, the strength is insufficient, and the weight becomes heavy. .

Further, the latter tension adjusting device shown in FIG.
Since the hardened material 9 comes into point contact, wear is inevitable and
A moment load acts on the tip of the rod 6, and the rod 6
There is also a risk of damage to the.

Further, also on the machined surface, a press-fitting hole for the quenching material 9 must be formed in a direction perpendicular to the fulcrum shaft 3, which causes a problem of high machining cost.

Therefore, the object of the present invention is to solve the above problems, so that the occurrence of wear in the contact portion between the rod and the pulley arm is extremely small, the smooth operation of the auto tensioner can be obtained, and the weight reduction and cost reduction can be achieved. It is an object of the present invention to provide a belt tension adjusting device.

[Means for Solving the Problems]

In order to solve the above problems, the present invention provides a pulley arm that is provided with a tension pulley that engages with a belt and is swingable around a fulcrum shaft, and an automatic rod arm that pushes the pulley arm in a belt tension direction. It is composed of a tensioner, the rod end of the auto tensioner is formed into a flat surface, and an insertion hole parallel to the fulcrum shaft is provided at a position corresponding to the rod end of the pulley arm made of light metal. A member is fixed, a notch is provided in a part of the portion where the insertion hole of the pulley arm is provided, and the flat surface of the rod end of the auto tensioner is brought into contact with the curved surface of the cylindrical receiving member exposed in the notch. It was adopted.

[Action]

In the auto tensioner that presses the pulley arm toward the tension side of the belt, the flat surface of the rod end contacts the curved surface of the receiving member attached to the pulley arm, and since the rod end is a flat surface, there is no moment load on the rod end. The occurrence of wear at the contact portion is small, and the pulley arm is made of light metal, which enables weight reduction.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4 of the accompanying drawings.

As shown in the figure, the tension adjusting device includes a tension pulley 12 that engages with a belt 11, and a pulley arm 14 that is swingable around a fulcrum shaft 13 and the pulley arm 14 that connects the belt 11 to the belt 11.
It is composed of an auto tensioner 15 that presses in the direction of tension of the
A receiving member 17 with which the rod 16 of 15 abuts is attached.

The auto tensioner 15 has a structure in which a mechanism for urging the elastic force that constantly projects the rod 16 forward in the axial direction is housed in a case 18, and the tip of the rod 16 has a flat surface 19
Is formed in.

The receiving member 17 attached to the pulley arm 14 is formed in a cylindrical shape. Specifically, as shown in the figure, a cylindrical roller which is a rolling element of a bearing is used, and the flat surface 19 of the rod 16 contacts the cylindrical surface. Is fixed to the pulley arm 14.

The pulley arm 14 has an insertion hole 20 for the fulcrum shaft 13, an insertion hole 22 for the support shaft 21 of the tension pulley 12, and an insertion hole for the receiving member 17.
The receiving member 17 is press-fitted or adhesively fixed to the insertion hole 23.

A notch 24 is provided in a portion of the pulley arm 14 where the insertion hole 23 is provided, and as shown in FIG. 2, the tip end flat surface 19 of the rod 16 is perpendicular to the portion of the receiving member 17 exposed in the notch 24. Abuts on.

As described above, since the tip end of the rod 16 is the flat surface 19 and the receiving member 17 of the pulley arm 14 is the cylindrical surface, the contact between the two becomes a line contact, and the occurrence of wear is reduced.

The force acting from the belt 11 is applied to the fulcrum shaft 13 and the receiving member 17.
When the tension pulley 12 swings around the fulcrum shaft 13, the contact portion between the receiving member 17 and the flat surface 19 of the rod 16 moves, but the tip end surface of the rod 16 is flat. surface
Since the pulley arm 14 side is the cylindrical surface of the receiving member 17 at 19, the force acting on the rod 16 is always only in the axial direction of the rod 16, and no moment load is generated in the auto tensioner 15.

〔effect〕

As described above, according to this invention, the cylindrical receiving member is fixed to the insertion hole of the pulley arm made of light metal, and the flat end of the rod is flattened on the curved surface of the cylindrical receiving member exposed in the notch provided in the insertion hole. Since the surfaces are brought into contact with each other, the moment load does not act on the rod of the autotensioner, the operation is smooth due to only the axial load, and the pulley arm is made of light metal, and the cylindrical receiving member is fixed in the insertion hole. Just good,
The arm structure is simple, and it is possible to achieve both weight reduction and high strength.

Further, since the pulley arm is provided with the insertion hole and the notch and only the cylindrical receiving member is fixed in the insertion hole, the number of processing and the number of parts can be reduced, the assembling work can be facilitated, and the cost can be reduced. Become.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of a tension adjusting device according to the present invention, FIG. 2 is a perspective view of an essential part of the same, and FIG. 3 is a partially cutaway side view showing a contact portion between a rod and a receiving member. FIG. 4 is a sectional view taken along the arrow IV-IV in FIG. 1, and FIGS. 5 and 6 are front views showing a conventional tension adjusting device. 11 …… belt, 12 …… tension pulley, 13 …… fulcrum shaft, 14 …… pulley arm, 15 …… auto tensioner, 16
…… Rod, 17 …… Receiving member, 19 …… Flat surface.

Claims (1)

[Scope of utility model registration request] 1. A tension pulley that engages with a belt, comprises a pulley arm that can swing about a fulcrum shaft, and an auto tensioner that pushes the pulley arm in a belt tension direction with a rod. The rod tip is formed on a flat surface, an insertion hole parallel to the fulcrum shaft is provided at a position corresponding to the rod tip of the pulley arm using light metal, and a cylindrical receiving member is fixed in the insertion hole.
A belt tension adjusting device in which a notch is provided in a part of a portion where an insertion hole of a pulley arm is provided, and a flat surface of a rod tip of an auto tensioner is brought into contact with a curved surface of a cylindrical receiving member exposed in the notch.