JP2001289292A - Auto tentioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure to prevent tooth flying of a timing belt and besides to facilitate a work to assemble an auto tentioner to a cylinder block. SOLUTION: When the tension of a timing belt is increased to a value higher than a given value, a pulley 7 continues suppression without moving aside from a timing belt through engagement between an arm piece 39 on the fixed side and an engaging part 35a on the oscillation side. During assembly, relative displacement between a plate 29 on the fixed side and a plate 32 on the oscillation side is prevented from by a lock pin 44 and displacement in a phase between the arm piece 39 on the fixed side and the engaging part 35 on the oscillation side is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The auto tensioner according to the present invention is used, for example, to apply an appropriate tension to a timing belt of an automobile engine.

[0002]

2. Description of the Related Art An appropriate tension is applied to a belt such as a timing belt for rotating and driving a camshaft of an OHC type or DOHC type engine in synchronization with a crankshaft by an automatic tensioner. 4 to 6
An example of an auto tensioner used for such a purpose is described in JP-A-8-61446. An auto-tensioner 2 that elastically presses an intermediate portion of the belt 1 and applies a predetermined tension to the belt 1,
By combining parts as shown in FIG.
It is configured as shown in FIG. FIG. 6 shows a disassembled state.
Here, for the sake of simplicity, the number of some members is drawn smaller than that in FIG. 5 showing an actual case. Further, the swinging member 5 shown in FIGS. 4 and 5 and the swinging member 5 shown in FIG. 6 have slightly different shapes at the front end portion (the left end portion in FIGS. 5 and 6). Are the same, and are substantially the same.

First, a fixing member 3 is fixed to a bolt 16 (FIG. 6).
Thereby, it is fixed to the front surface of a cylinder block (not shown) which is a fixed portion. The fixed member 3 is provided with a cylindrical fixed shaft 4, and a swing member 5 is provided around the fixed shaft 4.
Are rotatably supported via slide bearings 6a and 6b. The outer peripheral surface of the tip portion (left end portion in FIGS. 5 and 6) of the swing member 5 forms a cylindrical surface eccentric with respect to the fixed shaft 4. A pulley 7 is provided around the tip of the swing member 5.
Is rotatably supported via a rolling bearing 8 such as a deep groove ball bearing. Also, the base end of the swing member 5 (FIGS.
A bracket 9 is externally fitted and fixed to the outer peripheral surface (right end of 6). A locking portion 10 is provided on a part of the bracket 9 so as to protrude outward in the diameter direction. A tension spring 24 (FIG. 4) is provided between the locking portion 10 and another locking portion provided on the front surface of the cylinder block. The tension spring 24 imparts elasticity to the swing member 5 in a direction of pressing the pulley 7 toward the belt 1.

A cylindrical closed space 1 is provided between the outer peripheral surface of the intermediate portion of the fixing member 3 and the inner peripheral surface of the intermediate portion of the swinging member 5.
1 is provided. Both ends in the axial direction (left-right direction in FIG. 5) of the closed space 11 are closed by seal rings 12a and 12b, respectively. And in the inner part of this closed space 11,
A plurality of inner circular plates 13, 13 and outer circular plates 14, 14 are alternately arranged in the axial direction (the left-right direction in FIGS. 5 and 6). Of these two annular plates 13, 14, the inner annular plates 13, 13 have their inner peripheral edges fixed to the outer peripheral surface of the fixing member 3. That is, the fixing member 3
Between the flange portion 15 formed at the base end portion and the inner annular plate 13 located at one end side (the right end side in FIGS. 5 and 6), between the adjacent inner annular plates 13 and 13, and at the other end. Annular spacers 18 are interposed between the inner circular plate 13 located on the side (left end side in FIGS. 5 and 6) and the fixing plate 17 which is externally fixed to the fixing member 3. Then, the fixing plate 17
Is strongly pressed toward the flange portion 15.

On the other hand, a plurality of engaging projections 19, 19 (FIG. 6) are formed on the outer peripheral edges of the outer annular plates 14, 14, respectively. To
Engagement grooves 20 formed on the inner peripheral surface of the swing member 5
(FIG. 5) is displaceably engaged in the axial direction (left-right direction in FIGS. 5 and 6). The thickness dimension of each of the spacers 18 is slightly larger than the thickness dimension of each of the outer annular plates 14. Therefore, as described above, in a state where the inner and outer circular plates 13 and 14 are alternately arranged, a minute gap is formed between the side surfaces of the adjacent circular plates 13 and 14. As described above, the viscous liquid such as silicone oil is filled in the sealed space 11 in which the inner and outer circular plates 13 and 14 are alternately arranged. The filling of the viscous liquid is performed through the injection hole 22 formed in the swing member 5, and after the filling, the opening of the injection hole 22 is closed by pushing the steel ball 23.

[0006] The auto tensioner 2 configured as described above.
Can elastically press the pulley 7 toward the belt 1 by the elastic force of the tension spring 24. Further, by minimizing the static friction in the swinging direction, the tension of the belt 1 is always kept constant irrespective of the dimensional change of the belt 1 due to the temperature change. In addition, the plurality of inner circular plates 1
The side surfaces of the third and third plates 13 and the side surfaces of the outer circular plates 14 and 14 face each other via a minute gap, and a viscous liquid exists in the minute gap. Therefore, abrupt displacement between the two annular plates 13 and 14 is prevented by the shearing force applied to the viscous liquid existing in the minute gap. Therefore, even when the tension of the belt 1 changes over time due to the operation of the engine, the displacement of the pulley 7 can be suppressed by the shearing force applied to the viscous liquid. As a result, even when the tension of the belt 1 suddenly rises and then suddenly drops when the tension suddenly changes, the slack of the belt 1 can be kept constant.

However, in the case of the conventional auto-tensioner constructed and operated as described above, the displacement of the pulley 7 cannot be regulated as it is. On the other hand, when the tension of the belt 1 suddenly increases, it is necessary to suppress the belt 1 by restricting the excessive displacement of the pulley 7. The reason for this is that if the pulley 7 is retracted in response to a sudden rise in the tension of the belt 1 in part, the tension in the other parts of the belt 1 becomes too low. If the tension of the belt 1 is too low, so-called tooth skipping occurs when the belt 1 is a timing belt. In addition, in all types of belts, the fluttering that the belt vibrates greatly occurs, which leads to a reduction in the life of the belt 1 and an increase in noise of the belt driving unit.

This point will be described in detail with reference to FIG. A driving pulley 25 fixed to the end of the crankshaft 21 and rotating clockwise in FIG. 7 during operation of the engine as indicated by an arrow α, and a driven pulley 27 fixed to the ends of the camshafts 26 and 26, 27, the belt 1 is stretched. In the middle of the belt 1, a guide pulley 28 whose position is fixed and an auto tensioner 2 which is an object of the present invention are provided. And this auto tensioner 2
Is elastically pressed toward the belt 1 by the elastic force of the tension spring 24, and this belt 1
To the appropriate tension.

When the engine is stopped, the driving pulley 2
With the sudden stop of 5, the tension in the section A where the auto tensioner 2 is installed rises rapidly in a part of the belt 1, and the pulley 7 is pushed in the direction of arrow β. When the pulley 7 of the auto tensioner 2 is retracted from the position indicated by the solid line in FIG. 7 to the position indicated by the broken line in FIG. The tension in the C section located between the pair of driven pulleys 27, 27 may be excessively reduced, and the tooth jump may occur as described above. Conventionally, in order to prevent the timing belt from skipping due to such a cause, for example, Japanese Unexamined Patent Application Publication No.
As described in JP-A-61446, a stopper for limiting the swing amount of the swing member 5 supporting the pulley 7 has been provided.

However, in the case of the conventional structure described in JP-A-8-61446, one of the members for installing the auto tensioner, such as forming an arc-shaped engagement hole on the front surface of the cylinder block of the engine. It is necessary to apply special processing to the part. For this reason, not only does the cost increase, but it is necessary to design a dedicated auto-tensioner for each engine. In other words, the versatility of the auto-tensioner is poor, which causes an increase in cost.

[0011]

DESCRIPTION OF THE PRIOR ART An auto-tensioner invented in view of such circumstances is disclosed in Japanese Patent Application No. 10-302060. 8 to 10 show an auto-tensioner 2a according to the present invention according to the present invention. The feature of the auto-tensioner 2a according to the invention is that a displacement limiting means is provided between the fixed member 3 and the swinging member 5 so that the swinging member 5 and the pulley 7 pivotally supported by the swinging member 5 can be moved. The point is that the amount of displacement is limited. The configuration and operation of the other parts are the same as those of the above-described conventional structure.

In order to provide the displacement limiting means, a fixed plate 29 is fixed to the base end (right end in FIG. 10) of the fixing member 3. The fixed side plate 29 is formed by pressing a metal plate having sufficient rigidity. The fixed side plate 29 is formed by fitting a cylindrical portion 30 formed at the center portion to the base end portion of the fixed member 3 by interference fitting. It is fixed to this fixing member 3. A tongue piece 31 is provided on the outer peripheral edge of the fixed side plate 29 so as to project outward in the diameter direction. The first half of the tongue piece 31 is bent at a substantially right angle toward the swinging side plate 32 described below to form a fixed side engaging portion 33.

A swinging plate 32 is fixed to the base end (the right end in FIG. 10) of the swinging member 5. This rocking side plate 32 is formed by pressing a metal plate having sufficient rigidity. The cylindrical portion 34 formed at the center portion is fitted to the base end portion of the rocking member 5 by interference fitting. Thus, the swing member 5 is fixed. A tongue-shaped swing-side engaging portion 35 is provided on the outer peripheral edge of the swing-side plate 32.
Are projected outward in the diameter direction. A hexagonal square hole 36 is formed in the tip end surface of the swing member 5.
The square hole 36 displaces the swinging member 5 in a swinging manner against the elasticity of the tension spring 24 (see FIG. 4) having one end locked to the locking portion 10 so that the belt 1 is wound around the pulley 7. At this time, it is used to lock the tip of a tool such as a hexagon wrench.

In the case of the auto-tensioner 2a according to the first aspect of the invention, the fixed side engaging portion 33 protruding from the outer peripheral edge of the fixed side plate 29 and the swing side plate 3
Displacement limiting means including a swing-side engaging portion 35 formed on the outer peripheral edge of the swing member 2 limits the displacement of the swing member 5 and the pulley 7 pivotally supported by the swing member 5. That is, with the tension of the belt 1 stretched over the pulley 7, the pulley 7
8A and 9B, the swing displacement amount of the swing member 5 about the fixed shaft 4 is limited regardless of the force applied in the direction of arrows FF in FIGS. That is, the force applied in the direction of the arrow FF increases, and the swinging member 5 moves counterclockwise in FIG. 8 and clockwise in FIG. 9 against the elasticity of the tension spring 24 (see FIGS. 4 and 7). In the case of the swing displacement, the fixed side engaging portion 33 and the swing side engaging portion 35 abut against each other, so that the pulley 7 is not further displaced from the belt 1 in the retreating direction. Therefore, if the positions of the fixed side engaging portion 33 and the swing side engaging portion 35 are regulated, the displacement of the pulley 7 is regulated to a desired value, and the belt 1 is moved in the section A in FIG. The pulley 7 can be prevented from retreating excessively from the belt 1 even when the tension of the belt 1 rises sharply. As a result, it is possible to prevent the tension in the section B facing the fixed guide pulley 28 in a part of the belt 1 and the section C (see FIG. 7) between the pair of driven pulleys 27 and 27 from being excessively reduced. Thus, problems such as the tooth skipping described above are prevented from occurring.

[0015]

In the case of the auto-tensioner 2a according to the invention, which is constructed and operates as described above, the outer peripheral surface of the pulley 7 is pressed against the belt 1 to apply a predetermined tension to the belt 1. Therefore, it is necessary to make the phases of the fixed-side engaging portion 33 and the swing-side engaging portion 35 appropriate to obtain desired performance. If the distance between the fixed side engaging portion 33 and the swing side engaging portion 35 is too large in a state where a predetermined tension is applied to the belt 1, if the belt 1 When the tension suddenly rises, the pulley 7 cannot be prevented from retreating from the belt 1 excessively,
It is impossible to prevent the tension in the section B facing the fixed position guide pulley 28 in a part of the belt 1 and the section C between the pair of driven pulleys 27, 27 from excessively decreasing. Conversely, if the distance between the fixed side engaging portion 33 and the swing side engaging portion 35 is too short in a state where a predetermined tension is applied to the belt 1, the tension of the belt 1 increases in the section A. In this case, the pulley 7 cannot be sufficiently retracted, so that the tension of the belt 1 cannot be prevented from excessively increasing in the section A, and the life of the belt 1 is reduced.

On the other hand, the fixed member 3 provided with the fixed side engaging portion 33 and the swinging member 5 provided with the swinging side engaging portion 35 are provided before mounting to a fixed portion such as a cylinder block. In the state, relative rotation is relatively easy. Therefore, the phase of the fixed side engaging portion 33 and the phase of the swinging side engaging portion 35 may be different from each other. If the auto-tensioner 2a is mounted on the fixed portion in this state, the distance between the fixed-side engaging portion 33 and the swing-side engaging portion 35 may be inappropriate.

In view of such circumstances, the auto-tensioner of the present invention provides a fixing member 3 having the above-mentioned fixed side engaging portion 33.
The invention has been made to properly maintain the phase of the swing member 5 provided with the swing side engaging portion 35. Incidentally, as a structure for regulating the relative displacement between the fixed member and the swinging member before the engine is assembled to the cylinder block, for example, as described in JP-A-8-4859,
It is known that a stopper pin is bridged between the two members. However, the structure described in the above publication is intended to allow the belt to be easily passed over the pulley regardless of the elasticity of the spring for applying tension, It is not intended to make the phases of the fixed-side engaging portion and the swing-side engaging portion appropriate in a state where the tension is applied.

[0018]

The auto-tensioner according to the present invention comprises a fixing member fixed to a fixed portion such as a cylinder block of an engine, similarly to the conventional auto-tensioner shown in FIGS. A fixed shaft provided on the fixed member, a swing member rotatably supported around the fixed shaft, and a part of the swing member rotatably supported on a portion eccentric to the fixed shaft. A pulley, a rocking plate fixed to a portion of the outer circumferential surface of the rocking member that is axially displaced from the pulley, and both ends of the rocking plate and the fixed portion are locked. In this case, a spring is provided for imparting elasticity to the swing member in a direction of pressing the pulley toward the belt.

In particular, the automatic tensioner according to the present invention has a displacement limiting means and a phase setting means. Among these, the displacement limiting means includes a fixed-side engaging portion protruding from a part of the fixed-side plate fixed to the fixed member, and a part of the oscillating-side plate, along with the swing of the swinging member. And a swing-side engaging portion projecting from a position where the fixed-side engaging portion is engaged. Further, the pulley has a function of restricting swinging displacement of the pulley in the retreating direction from the belt. Further, the phase setting means has a function of setting the phase of the fixed side engaging portion and the swing side engaging portion to a predetermined state. Note that setting the phase to a predetermined state in this way means that the pulley is displaced from the initial state until the fixed side and swing side engagement portions are engaged with each other due to fluctuations in the tension of the belt. This also refers to setting the phase between these fixed-side and swing-side both engaging portions to such an extent that tooth jump does not occur on the belt. As the phase setting means, any means can be used as long as the phase between the fixed side engaging portion and the swing side engaging portion can be set to a predetermined state. A member such as a locking pin for temporarily suppressing the relative displacement with the joint portion may not be provided. For example, by providing a phase setting mark or the like such as a locking hole, it is possible to use the phase setting means.

Further, in the case of the auto-tensioner according to the present invention, the phase setting means includes a swing-side locking hole formed in a part of the swing-side plate and a part of the fixed-side plate. It has a fixed side locking hole formed at a portion aligned with the swing side locking hole, and a locking pin which can be inserted through the rocking side, fixed side and both locking holes without play. Then, the phase of the fixed side engaging portion and the phase of the swinging side engaging portion are set to a predetermined state in a state where the locking pin is inserted through the swinging side, the fixed side, and both the locking holes.

Further, in the case of the auto tensioner according to the third aspect, the locking pin is made of an elastic metal wire, and a folded portion is provided at an intermediate portion of the wire and a swinging side is fixed to one end of the wire. And the other end portion, and the one end portion is inserted into the swinging side, the fixed side, and both the locking holes, and the swinging side plate or the fixed side is inserted. A retaining engagement portion is provided for engaging the outer peripheral edge of the plate to prevent the one end from falling out of the swinging side, the fixed side, and both the locking holes.

Further, in the case of the auto-tensioner according to the fourth aspect, the phase setting means is provided radially outward of the pulley with respect to the outer peripheral surface of the pulley. Furthermore,
In the case of the auto-tensioner according to the fifth aspect, at least one of the fixed-side engaging portion and the swing-side engaging portion is provided with a part of the phase setting means.

[0023]

When the auto tensioner of the present invention configured as described above swings the swing member about the fixed shaft by the elastic force of the spring, and presses the pulley against the belt to apply an appropriate tension to the belt. Is the same as that of the conventional auto tensioner described above.

In particular, in the case of the auto-tensioner of the present invention, similarly to the auto-tensioner according to the prior invention shown in FIGS. The displacement of the supported pulley can be limited. Therefore, the displacement amount of the pulley is restricted to a desired value, so that the pulley can be prevented from retreating excessively even when the tension of the belt suddenly rises.

Further, according to the auto tensioner of the present invention, the fixed member provided with the fixed side engaging part constituting the displacement limiting means and the swing side engaging part are provided by the phase setting means. The phase with the swing member provided with can be made appropriate.
Therefore, if the auto tensioner is assembled to a fixed portion such as a cylinder block in a state where the phase of the fixed member and the swinging member is regulated by the phase setting means so that a predetermined tension can be applied to the belt. Thus, an appropriate tension can be applied to the belt, and the phases of the fixed-side engaging portion and the swing-side engaging portion can be made appropriate.

Further, according to the auto tensioner of the present invention, the fixing member provided with the fixed side engaging portion forming the displacement limiting means by the locking pin forming the phase setting means, and the swinging side. The phase with the rocking member provided with the engaging portion can be made appropriate and maintained as it is. Therefore, while the displacement of the fixed member and the swinging member is limited by the locking pin, the auto tensioner is assembled to a fixed portion such as a cylinder block or the like so that a predetermined tension can be applied to the belt. , The locking pin swinging side,
If the belt is pulled out from both the fixing holes on the fixed side, an appropriate tension is applied to the belt, and the phase between the fixed side engaging portion and the swing side engaging portion can be made appropriate.

According to the auto-tensioner according to the third aspect, it is possible to prevent the locking pin from accidentally dropping off during the assembling operation of the auto-tensioner, and to efficiently perform the assembling operation. Further, according to the automatic tensioner according to the fourth aspect, since the phase setting operation can be performed without disturbing the pulley, the phase setting operation can be easily performed. Further, according to the auto-tensioner according to the fifth aspect, a part of the component for providing the phase setting means is omitted, and the size and weight can be reduced.

[0028]

1 and 2 show a first embodiment of the present invention. A feature of the present invention is a structure having a function of preventing the pulley 7 from retreating excessively when the tension of the belt suddenly rises, without complicating the assembling work to a fixed portion such as a cylinder block. The structure is to ensure that the above functions can be exhibited. The basic structure of the auto-tensioner is the same as the conventional structure shown in FIGS. 4 to 6 described above, and the structure for exerting the function of preventing the pulley 7 from retreating excessively as described above is the same as that shown in FIG. This is the same as the structure according to the prior invention shown in FIGS. Therefore, the same reference numerals are given to the same portions as those of the conventional structure and the structure according to the present invention, and the duplicated description is omitted. Hereinafter, the characteristic portions of the present invention, The following description focuses on the differences from the structure according to the preceding invention.

The auto-tensioner 2b according to the present invention includes a displacement limiting means 37 and a phase setting means 38. Among these, the displacement limiting means 37 is also incorporated in the above-described auto-tensioner 2a (FIGS. 8 to 10) according to the above-mentioned invention, so that the pulley 7 is retracted from the belt 1 (see FIGS. 4 and 7). It has a function to limit swing displacement. However,
In the case of the auto-tensioner 2b of this example, a fixed-side arm piece 39 is formed on a part of the outer peripheral edge of the fixed-side plate 29 externally fixed to the fixed member 3 so as to protrude outward in the radial direction. The side arm 39 has a role as a fixed side engaging portion described in the claims. On the other hand, an extended portion 40 is formed on a part of the outer peripheral edge of the swing-side plate 32 externally fixed to the swing member 5 so as to protrude radially outward, and the circle of the extended portion 40 is formed. One edge in the circumferential direction (the lower left edge in FIG. 2) is bent at a right angle to the side of the fixed plate 29 to form a swing-side engaging portion 35a. When the auto tensioner 2b is used, one surface (the lower left surface in FIG. 2) of the swing-side engaging portion 35a and one edge (the right edge in FIG. 2) of the fixed arm 39 are usually separated from each other. However, when the tension of the belt 1 suddenly rises, the one surface and one side edge abut (engage).
Then, the pulley 7 is prevented from being excessively displaced in the direction of retreating from the belt 1.

The swinging side plate 32 is externally fixed to a portion of the outer circumferential surface of the swinging member 5 which is separated from the pulley 7 in the axial direction (to the right in FIG. 1). Therefore, even when the prevention of the interference between the swing-side plate 32 and the pulley 7 is considered, it is not necessary to increase the diameter of the pulley 7 more than necessary, and the size of the auto tensioner can be reduced. In the case of the present example, the thickness of the rocking side plate 32 in the axial direction of the fixed member 3 and the rocking member 5 is made smaller than the thickness of the fixed side plate 29 in the axial direction. One end in the circumferential direction of the extending portion 40 formed on a part of the outer peripheral edge of the side plate 32 is bent at a right angle to the fixed side plate 29 to form the swing-side engaging portion 35a.
Therefore, the bending process of the swing side engaging portion 35a can be easily performed, but it is not necessary to perform the bending process on the fixed side plate 29 having a large thickness. Therefore, the processing for forming the displacement limiting means is easy, and the cost can be reduced.

In order to constitute the phase setting means 38,
In the illustrated example, a swing-side arm piece 41 is formed at a part of the swing-side plate 32 that is circumferentially deviated from the extending portion 40 at a part of the outer peripheral edge thereof so as to protrude radially outward. ing. A swing-side locking hole 42 is formed at the tip of the swing-side arm 41.
Into the fixed-side locking piece 43 at the distal end of the fixed-side arm piece 39.
Are formed respectively. The rocking side, the fixed side, and the locking holes 42 and 43 are aligned with each other with the rocking displacement of the rocking member 5 about the fixed shaft 4.

The distal end of the locking pin 44 is inserted into the swinging side, the fixed side, and the locking holes 42 and 43 without looseness. The locking pin 44 is formed by bending an elastic metal wire such as spring steel, and has a folded portion 45 at an intermediate portion, and the swinging side, fixed side, both locking holes 42 at one end. An insertion portion 46 that can be freely inserted into 43 is provided, and a retaining engagement portion 47 is also provided at the other end. The insertion portion 46 has a slightly smaller diameter than the other portions, and can be freely inserted into the swinging side, the fixed side, and the locking holes 42 and 43 without play. In addition, the above-described retaining engagement portion 47
Is formed by bending the other end of the wire into an "H" shape in which the side facing the insertion portion 46 is concave, and inserting the insertion portion 46 through the swing side, the fixed side, and the locking holes 42, 43. In this state, it engages with the outer peripheral edge of the swing-side plate 32, and the insertion portion 46 moves the swing-side, fixed-side, and both locking holes 42, 4.
It has the role of preventing the slipping out of 3. The portion of the wire constituting the locking pin 44 that is bent into an "H" shape may be engaged with the outer peripheral edge of the fixed side plate 29.

When the insertion portion of the locking pin 44 is inserted through the swinging side, the fixed side, and the locking holes 42 and 43 as described above, the fixed member 3 and the fixed side plate 29 are connected to the swinging side. The relative displacement between the member 5 and the swing side plate 32 is prevented. Then, the phases of the fixed-side arm piece 39 and the swing-side engaging portion 35a provided on both of the plates 29 and 32 are regulated to a predetermined state.

In the case of the auto tensioner 2b of the present invention constructed as described above, the displacement restricting means 37 composed of the fixed arm piece 39 and the oscillating side engaging portion 35a is used for the above-mentioned FIGS. Auto-tensioner 2 according to the prior invention shown in FIG.
Similarly to a, the displacement of the swing member 5 and the pulley 7 pivotally supported by the swing member 5 can be limited. Therefore, by controlling the displacement of the pulley 7 to a desired value, even when the tension of the belt 1 rises sharply, the pulley 7 is prevented from retreating excessively, and problems such as tooth skipping of the timing belt may occur. It can be prevented from occurring.

Further, according to the auto-tensioner 2b of this embodiment, the displacement limiting means 37 is provided by the phase setting means 38 comprising the swinging side, the fixed side, the locking holes 42, 43 and the locking pin 44. The phase of the fixed member 3 provided with the fixed-side arm piece 39 and the swing member 5 provided with the swing-side engaging portion 35a can be appropriately maintained. In other words, before assembling to a fixed portion such as a cylinder block, the fixed member 3 and the swing member 5 are inadvertently rotated relative to each other, and the fixed arm 39 and the swing engagement portion 35a are Phase will not deviate from the expected one.

The work of assembling the auto tensioner 2b to the fixed portion is performed by inserting the locking pin 44 into the swinging side, the fixed side, and the locking holes 42 and 43, and by the phase setting means 38 The operation is performed while the displacement between the fixed member 3 and the swing member 5 is limited. Then, the auto tensioner 2b is assembled to the fixed portion so that a predetermined tension can be applied to the belt 1. In this operation, before the bolt 16 (see FIG. 6) inserted into the fixed shaft 4 provided on the fixed member 3 is tightened, the fixed member 3 is swung about the bolt 16 so that the pulley 7 This is performed by tightening the bolts 16 with the outer peripheral surface pressed against the belt 1. In this way, after the fixing member 3 is supported and fixed to the fixed portion in a state where a desired tension can be applied to the belt 1 by the pulley 7, the locking pin 44 constituting the phase setting means 38 is moved. , The swinging side,
Pull out the fixing side from both locking holes 42 and 43. By performing these series of operations, the phase between the fixed-side arm piece 39 and the swing-side engaging portion 35a can be properly adjusted in an initial state in which an appropriate tension is applied to the belt 1.

The fixed-side arm 39 and the swing-side engaging portion 35a
As shown in FIG. 3 showing a second embodiment of the present invention, cushioning members 48, 48 are provided on at least one of the surfaces facing each other. If the cushioning members 48, 48 or the cushioning members 48 and the fixed-side arm piece 39 or the swing-side engaging portion 35a are brought into contact with each other when the cushioning member 35a approaches, hard metal is used. By preventing contact between certain steels, it is possible to prevent the generation of harsh striking sounds. The cushioning members 48, 48 may be of any type as long as they can reduce the hitting sound at the time of abutting. For example, a material having a large internal loss, such as rubber, synthetic resin, or lead, may be adhered by bonding or coating. It is feasible.

[0038]

Since the present invention is constructed and operates as described above, it is possible to realize an automatic tensioner at a low cost which can prevent the occurrence of inconvenience such as tooth skipping of the timing belt. In particular, when assembling to a fixed part such as an engine cylinder block, it is possible to achieve both appropriate tension application to the belt and prevention of the above-mentioned problems without performing any troublesome adjustment work. The price can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first example of an embodiment of the present invention.

FIG. 2 is a rear view showing a state where a locking pin is omitted.

FIG. 3 is a rear view showing a second example of the embodiment of the present invention.

FIG. 4 is a front view showing an example of a conventional structure.

FIG. 5 is a sectional view of the same.

FIG. 6 is an exploded perspective view of the same.

FIG. 7 is a schematic front view showing an installation portion of the auto tensioner.

FIG. 8 is a front view showing an example of the embodiment of the present invention.

FIG. 9 is a rear view of the same.

FIG. 10 is a sectional view taken along line AA of FIG. 8; DESCRIPTION OF SYMBOLS 1 Belt 2, 2a, 2b Auto tensioner 3 Fixing member 4 Fixed shaft 5 Oscillating member 6a, 6b Sliding bearing 7 Pulley 8 Rolling bearing 9 Bracket 10 Locking part 11 Sealed space 12a, 12b Seal ring 13 Inner circular plate 14 Outside Ring plate 15 Flange 16 Bolt 17 Fixing plate 18 Spacer 19 Engagement projection 20 Engagement groove 21 Crankshaft 22 Injection hole 23 Steel ball 24 Tension spring 25 Drive pulley 26 Camshaft 27 Follower pulley 28 Guide pulley 29 Fixed side plate Reference Signs List 30 cylindrical part 31 tongue piece 32 rocking side plate 33 fixed side engaging part 34 cylindrical part 35, 35a rocking side engaging part 36 square hole 37 displacement limiting means 38 phase setting means 39 fixed side arm piece 40 extension part 41 Swing-side arm piece 42 Swing-side lock hole 43 Fixed-side lock hole 44 Lock pin 45 Folded part 4 Retaining engagement portion 48 buffer member omission insertion portion 47

Claims (5)

[Claims] A fixed member fixed to a fixed portion, a fixed shaft provided on the fixed member, a swing member supported swingably around the fixed shaft; A pulley rotatably supported at a part eccentric to the fixed shaft, a swing-side plate fixed to the outer peripheral surface of the swing member, and the swing-side plate and the fixed portion An auto-tensioner having a spring that applies elastic force in a direction of pressing the pulley toward the belt by locking the both ends thereof, and includes a displacement limiting unit and a phase setting unit. Of these, the displacement limiting means includes a fixed-side engaging portion provided on a part of the fixed-side plate fixed to the fixed member, and a part of the oscillating-side plate, along with the swing of the swinging member. A swing-side engaging portion provided at a position to be engaged with the fixed-side engaging portion; Wherein the pulley has a function of restricting swinging displacement in a direction in which the pulley is retracted from the belt, and the phase setting means is provided between the fixed side engaging portion and the swinging side engaging portion. An auto-tensioner having a function of setting a phase to a predetermined state. 2. The oscillating side locking hole formed in a part of the oscillating side plate and a part of the fixed side plate which is aligned with the oscillating side locking hole. A fixed side locking hole is formed, and a locking pin which can be inserted through the swinging side, the fixed side, and both locking holes without looseness is provided. With the hole inserted,
The auto-tensioner according to claim 1, wherein a phase between the fixed-side engaging portion and the swing-side engaging portion is set to a predetermined state. 3. The locking pin is made of an elastic metal wire, and a folded portion is provided at an intermediate portion of the wire.
Similarly, one end has a swinging side, a fixed side, and an insertion portion that can be inserted into both locking holes, and the other end also has this one end inserted into the swinging side, the fixed side, and both locking holes. A stopper engaging portion for engaging the outer peripheral edge of the rocking side plate or the fixed side plate to prevent the one end from falling out of the rocking side, the fixed side, and both locking holes. The auto-tensioner according to claim 2, provided. 4. The phase setting means is provided radially outward of the pulley from an outer peripheral surface of the pulley.
The auto tensioner according to claim 1. 5. The phase setting means according to claim 1, wherein at least one of the fixed side engaging portion and the swing side engaging portion has a part of the phase setting means. Auto tensioner.