JP3159293B2 - Auto tensioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic tensioner for applying a predetermined tension by elastically abutting a tension pulley to an endless belt for transmitting power.

[0002]

2. Description of the Related Art Such an automatic tensioner is known, for example, from Japanese Patent Application Laid-Open No. Hei 6-280950.

In the above-mentioned conventional auto tensioner, a base end of an arm member having a tension pulley at a distal end is pivotally supported on a base member via a pivoting means so as to be swingable, and a spring disposed on the outer periphery of the pivoting means. By urging the arm member in the rotational direction, the tension pulley is pressed against the endless belt to apply a predetermined tension.

[0004]

However, in the above-mentioned conventional auto tensioner, the openings of the cylindrical peripheral walls provided on the base member and the arm member are opposed to each other via a predetermined gap. There is a problem that water and mud are unavoidable to enter and hinder the smooth operation of the pivot means and the spring.

When assembling, one end of the spring is previously assembled to the base member, and when the arm member is further assembled thereto, the other end of the spring is fitted inside the cylindrical peripheral wall of the arm member. In this case, it is difficult to perform the operation of locking the arm member, and it is necessary to perform the assembling operation while tilting and arming the arm member, resulting in poor workability.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an auto-tensioner which is less likely to malfunction due to water or mud and is easy to assemble.

[0007]

In order to achieve the above object, the present invention provides a base member, an arm member pivotally supported on the base member via a pivot member, and the pivot member. And a tension pulley that is axially supported by the arm member and pressed against the endless belt by the elastic force of the spring. An opening in a cylindrical fixed side peripheral wall provided in the base member ;
So that it is coaxially arranged with the same diameter as the fixed side wall
With the opening of the cylindrical movable wall provided in front Symbol arm member are opposed to each other, in the automatic tensioner which surrounds the outer periphery of the spring to cooperate the both peripheral wall, the opening of the movable side wall A raised portion having an enlarged diameter is formed on the periphery, and the raised portion covers the radially outer side of the opening of the fixed-side peripheral wall. Further, the inner peripheral surface of the movable-side peripheral wall extends in the axial direction to extend the raised portion. the groove-shaped engaging portion which opens into the inner stepped portion inner surface parts are formed, the locking portion of the groove, thereby locking the bent portion formed by bending an end portion of the spring radially outward, this The bent portion is locked to the groove-shaped locking portion.
When the ridge is bent, the inner step of the ridge serves as a guide for the bent portion.
Characterized in that that.

[0008]

Embodiments of the present invention will be described below.
A description will be given based on an embodiment of the present invention shown in the accompanying drawings.

1 to 8 show an embodiment of the present invention. FIG. 1 is an overall plan view of an auto tensioner, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG. 4, FIG. 4 is a plan view of the base member, FIG. 5 is a sectional view taken along line 5-5 of FIG. 4, FIG. 6 is a plan view of the arm member, FIG. 7 is a sectional view taken along line 7-7 of FIG. FIG. 8 is an operation explanatory view at the time of assembly.

As shown in FIGS. 1 to 5, an auto tensioner T for adjusting the tension of an endless belt B for transmitting a driving force of a crankshaft of an automobile to auxiliary devices such as a generator.
Is provided with a base member 1 fixed to the engine body E with two bolts 23,23. The base member 1 includes a substantially triangular mounting portion 2 that comes into contact with a mounting seat of the engine body E, a bottomed cylindrical fixed peripheral wall 3 that rises from the mounting portion 2,
An inner shaft 4 rising from the mounting portion 2 along the axis of the fixed side peripheral wall 3 is provided. Two bolt holes 2 ₁ , 2 through which the two bolts 23 are inserted are provided at both ends of the mounting portion 2.
₁ is formed. Also on the bottom surface within the periphery of the fixed side wall 3, the locking portion 3 ₁ which bent portion 5 ₁ formed by bending the lower end of the coiled torsion spring 5 to be described later radially outwardly to engage
Is recessed.

As is clear from FIGS. 6 and 7, the arm member 6 pivotally supported by the base member 1 is rotatably fitted to the outer periphery of the inner shaft 4 of the base member 1. An outer cylinder 7, a movable peripheral wall 8 having a bottomed cylindrical shape coaxially surrounding the outer periphery of the outer cylinder 7, an arm body 9 extending radially outward from the movable peripheral wall 8, and a radius of the arm body 9. A pulley shaft 10 protruding from the outer end in the direction and a peripheral wall 11 coaxially surrounding the outer periphery of the pulley shaft 10 are provided.

[0012] movable wall 8 is intended to be arranged coaxially with a same diameter as the fixed side wall 3, the peripheral edge of the opening ₈₁ of the lower end ridge ₈₂ of an enlarged diameter formed Is done. As is clear from FIG. 2, the raised portion 8 of the movable side peripheral wall 8 is formed.
₂ is arranged so as to cover the radially outer opening 3 ₂ of the upper end of the fixed wall 3, thus over the upper end of the lower end and the fixed side wall 3 of the movable wall 8 in a side view shown in FIG. 2 I'm wrapping. Also a groove-shaped engaging portion 8 ₃ extending in the axial direction is formed by bulging radially outwardly the inner circumferential surface of the movable side wall 8, radially upper end of the spring 5 to the engaging portion 8 ₃ bent portions 4 ₂ formed by bending outwardly is engaged (see FIG. 3).

When the outer cylinder 7 of the arm member 6 is pivotally supported on the inner shaft 4 of the base member 1, a cylindrical member formed between the outer peripheral surface of the inner shaft 4 and the inner peripheral surface of the outer cylinder 7 is formed. Resin inner braking body 1
2 is fitted, and an outer brake 13 made of a synthetic resin and formed in a substantially cylindrical shape is fitted on the outer peripheral surface of the outer cylinder 7.
The inner shaft 4, the outer cylinder 7, the inner brake 12, and the outer brake 1
3 constitutes a pivoting means 14 for pivotally supporting the arm member 6 on the base member 1.

[0014] spring 5 is accommodated in the outer friction member 13 spring accommodating space 15 defined between the inner periphery of the fixed side and the movable side wall 3,8 and the outer periphery of the bent portion 5 ₁ of the lower end together but to engage the locking portion 3 ₁ of the fixed wall 3,
Its bent portion 5 ₂ of the upper end is engaged with the locking portion 8 ₃ of the movable side wall 8. At this time, the lower end of the spring 5 is
By pressing the third flange portion 13 ₁ formed at the lower end on the bottom surface of the spring housing space 15, the rotation of the outer friction member 13 relative to the base member 1 is restricted.

A metal washer 16 and a resin washer 17 are superimposed on the upper end of the inner shaft 4 projecting upward from the arm member 6 and fixed by caulking 18. In this state, a predetermined compression load and a predetermined torsional load are applied to the spring 5.

A tension pulley 20 is rotatably supported on the pulley shaft 10 of the arm member 8 via a ball bearing 19, and is fixed with a bolt 22 via a dustproof washer 21 to prevent dust from adhering to the ball bearing 19. Is done. The peripheral wall 11 surrounding the outer periphery of the pulley shaft 10 is loosely fitted in a radially intermediate concave portion of the tension pulley 20 in order to prevent dust from adhering to the ball bearing 19.

Next, the operation of the embodiment of the present invention having the above configuration will be described.

The arm member 6 of the auto tensioner T can swing in the range of a to c in FIG. 1 and is in the position a by the elastic force of the spring 5 in a free state where it does not come into contact with the endless belt B. In the use state in which the tension of B acts, it swings to the vicinity of the position b against the resilience of the spring 5, and when the tension further increases, it can swing to the position c which is the limit position. When the tension of the endless belt B fluctuates during operation of the engine, the arm member 6 swings following the fluctuation. At this time, the inner brake body 12 and the outer brake body 13 and the movable side peripheral wall 8 move.
The dance of the arm member 6 is regulated by the frictional force acting between the arm member 6 and the arm member 6.

[0019] Now, if the water or mud is applied to the auto tensioner T with the running of the vehicle, the water or mud between the opening ₈₁ of the opening 3 ₂ and the movable side wall 8 of the fixed side wall 3 a gap From the spring storage space 15 and the spring 5
And the pivoting means 14 inside thereof may cause malfunction such as sticking.

However, in the present embodiment, the movable side peripheral wall 8
Radius since it is arranged such outward to cover, water in the direction of arrow A toward the engine body E auto tensioner T is attached in FIG. 2 ridges 8 ₂ of the opening 3 _second fixed side wall 3 of the even and mud hanging, the water or mud is blocked by the raised portion ₈₂ can not enter the spring housing space 15, thus malfunction of the spring 5 and pivot means 14 can be prevented.

Assembling of the arm member 6 to the base member 1 is performed in the following procedure. That is, the base member 1
The outer periphery of the inner shaft 4 with mounting the inner friction member 12 and the outer friction member 13 of the locking portion 3 ₁ of the fixed wall 3 a bent portion 5 ₁ of the lower its further wearing the spring 5 on the outer In advance. Push the arm member 6 to the base member 1 side in a state where the outer cylinder 7 is fitted between the two damping bodies 12, 13 of the arm member 6 from this state, finally bent portion 5 ₂ of the upper spring 5 it is sufficient engaged with the locking portion 8 ₃ of the movable side wall 8. At this time, the locking portion 8 ₃ movable wall 8
Due to the opening of the inner surface of the raised portion _82, the locking part 8
₃ it is not necessary to provide the twisting and tilting the arm member 6 to engage the upper side of the bent portion 5 ₂ of the spring 5 may simply rotates the arm member 6. That it is, as is clear from FIG. 8, since the inner stepped portion of the raised portion ₈₂ of the movable side wall 8 is above the bent portion 5 ₂ of the guide of the spring 5, the movable side only rotating the arm member 6 thereby the locking portion 8 ₃ of the peripheral wall 8 engaging the bent portion 5 ₂ of the spring 5.

Thus, workability when assembling the arm member 6 to the base member 1 can be improved. Moreover, conventionally had processed the locking portion on the inner surface of the movable side wall with a drill or the like, the arm member 6 according to this embodiment in the case of manufacturing by die casting or the like, the locking portion 8 ₃ integrally It is possible to form, and the number of processing steps can be reduced.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various design changes can be made.

For example, in the embodiment, an auto tensioner used for an endless belt B for driving an auxiliary device of an automobile has been exemplified. However, the present invention can be applied to an endless belt B for any other use.

[0025]

As described above, according to the present invention, a raised portion having an enlarged diameter is formed at the periphery of the opening of the movable side peripheral wall provided on the arm member, and the raised portion has an opening of the fixed side peripheral wall. A groove-shaped locking portion extending in the axial direction and opening on the inner surface of the inner step portion of the raised portion, is formed on the inner peripheral surface of the movable side peripheral wall; Since the bent portion formed by bending the end of the spring radially outward is locked to the locking portion, the gap formed in the facing portion between the opening in the movable side peripheral wall and the opening in the fixed side peripheral wall is formed. Makes it difficult for water and mud to enter. As a result, water and mud hardly adhere to the pivot means and the spring surrounded by the two peripheral walls, and the malfunction of the pivot means and the spring is effectively prevented. Also, when assembling, when assembling the arm member to the base member to which one end of the spring has been previously assembled, the other end of the spring is guided by a raised portion formed on the movable side peripheral wall of the arm member, and the other end of the spring is connected to the movable side peripheral wall. It can be smoothly engaged with the engaging portion formed on the inner peripheral surface. That results in the guide inner stepped portion of the ridges of the movable wall is against the bent portion of the spring the other end, simply rotates without or apply prying by tilting the arm member, the the raised portion
The bent portion at the other end of the spring can be smoothly locked to the groove-shaped locking portion opened on the inner surface of the inner step portion .

[Brief description of the drawings]

FIG. 1 is an overall plan view of an auto tensioner.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 1;

FIG. 4 is a plan view of a base member.

FIG. 5 is a sectional view taken along line 5-5 of FIG. 4;

FIG. 6 is a plan view of an arm member.

FIG. 7 is a sectional view taken along line 7-7 of FIG. 6;

FIG. 8 is an explanatory view of an operation at the time of assembly.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Base member 3 Fixed peripheral wall 3 ₂ Opening 5 Spring 6 Arm member 8 Movable peripheral wall 8 ₁ Opening 8 ₂ Raised part 8 ₃ Locking part 14 Pivot means 20 Tension pulley B Endless belt

Claims (1)

(57) [Claims] A base member (1) and a base member (1)
An arm member (6) pivotally supported via pivot means (14), and a base member (1) and an arm disposed on the outer periphery of the pivot means (14) and having opposite ends at both ends. A spring (5) locked to the member (6), and a tension pulley (20) supported by the arm member (6) and pressed against the endless belt (B) by the elastic force of the spring (5). it includes bets, opening of the base member (1) in a cylindrical fixed-side peripheral wall provided (3) and (3 _2), the
It is arranged coaxially with the same diameter as the fixed peripheral wall (3).
An opening portion of the cylindrical movable wall provided in so that prior Symbol arm member (6) (8) (8 ₁₎ and face each other, wherein both the peripheral wall (3,8) of said cooperating spring (5) in the auto tensioner which surrounds the outer periphery of the the periphery of the opening of the movable wall (8) (8 ₁₎ formed ridges enlarged diameter _(82), the raised portion (8 ₂ ) Covers the outside of the fixed side peripheral wall (3) in the radial direction of the opening (3 ₂ ), and the inner peripheral surface of the movable side peripheral wall (8) extends in the axial direction to form the raised portion (8 ₂ ). groove-shaped engaging portion which opens into the inner stepped portion <br/> surface to form a (8 _3), the groove-like engaging portion (8 _3), the ends of the spring (5) radius bent portions formed by bending in a direction outwardly (5 ₂₎ and a locked, this bent portion (5 ₂₎ of the groove-like engaging portion (8 ₃₎
Inner stepped portion of the raised portion when engaged ₍₈₂₎ is該折
Auto tensioner, characterized in that the guide tracks (5 _2).