JPH0318065B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a belt auto-tensioner suitable for maintaining appropriate belt tension and preventing and damping belt tension fluctuations and resonance in a belt drive mechanism. It is related to.

(Prior Art) Conventionally, an autotensioner has been used as a tension applying means in a belt transmission device in which a transmission belt is wound between a driving pulley and a driven pulley. Generally used autotensioners use hydraulic pressure, pneumatic pressure, rubber, steel springs, resin springs, etc. to apply tension to the belt by means such as compression, tension, bending and twisting.

To give a specific example of this method, a tensioner shaft is inserted into a cylindrical case, has an idler pulley at its tip, a ball bearing or bushing is inserted into the inner surface, and also serves as a spring stopper. The arm is attached, and a torsion spring is inserted into the outer circumferential surface of the tensioner shaft between the cylindrical case and the tension arm, and the tension arm rotates around the shaft due to the torsional force of the spring, thereby tightening the belt. This is the configuration to give.

In the auto-tensioner with the above configuration, the idler pulley is pressed against the side surface of the belt, and the tension arm swings in response to changes in belt tension to apply appropriate tension. A damper member has been added to the above-mentioned structure for the purpose of quickly converging the swinging motion of the belt and reducing the burden on the belt itself and driven objects.

Conventional damper members include those that generate resistance by operating a piston or impeller in liquid, and those that utilize a clutch-like friction plate (US Pat. No. 4,661,087).

(Problems to be Solved by the Invention) Although the conventional autotensioner having a damper member has the advantage that the tension arm stops swinging quickly due to the resistance of the damper, it has the disadvantage that its external size inevitably increases. It was hot.

For this reason, it has been difficult to employ conventional autotensioners as autotensioners for automobile applications, where there is a large restriction on the mounting space for the autotensioner.

SUMMARY OF THE INVENTION The present invention focuses on these drawbacks of conventional autotensioners, and aims to provide an autotensioner that has a damper effect and is small in external size.

(Means for Solving the Problem) The gist of the present invention for achieving the above object is that a tension arm, to which an idler pulley is rotatably fixed at one end, is a mounting member for attaching an autotensioner to another member. In an auto tensioner, a torsion spring is rotatably fixed to a tensioner shaft provided with a mounting member or a torsion spring is interposed between the tensioner shaft and the tension arm, and the torsion spring has wires coated with resin and adjacent to each other. The auto tensioner is characterized in that the coated wires are in contact with each other.

The autotensioner of the invention is used by pressing an idler pulley against a belt with a torsion spring wound or unwound in the same manner as the conventional one. When the tension of the belt changes and the tension arm swings, the adjacent strands of the torsion spring move in the circumferential and axial directions, but in the present invention, the spring strands are coated with resin. , and since adjacent resins are in contact with each other, they rub against each other, causing friction and deformation.

Energy is absorbed by this frictional force and the deformation of the resin, and the swinging motion of the tension arm is attenuated and converged.

Furthermore, similar effects can be expected when the wires of the spring are not covered with resin but are entirely or partially buried in resin. When the spring is entirely or partially embedded in resin, the damping effect is mainly achieved by deformation of the resin.

(Example) Specific examples of the present invention will be further described below.

FIG. 1 shows an example of an autotensioner according to the present invention. In the figure, a denotes the autotensioner, _S1 denotes a tensioner shaft having a small diameter portion and an intermediate large diameter portion continuous to this, and 1 denotes another member 2. It is a mounting member fixed to the other member 2, and has a cylindrical case shape with a flange part, and the flange part is bolted to another member 2.
The tensioner shaft S ₁ is fixed by being tightened by V ₁ and V ₂ , and a tension arm 5 having a ball bearing or bushing 4 inserted into the other end of the tensioner shaft S 1 is attached to the other end of the tensioner shaft S _{1 .} At the tip of the tension arm 5, an idler pulley 6 is inserted into the tip shaft _S2 of the tension arm via a ball bearing 7 and fixed as a nut. ing.

A coil spring 8 is inserted between the bottom surface of the tension arm 5 and the bottom surface of the cylindrical mounting member 1, and one end of the spring 8 is connected to a groove in a bowl-shaped stopper 9 provided integrally with the tension arm 5. 10, while the other end is inserted and locked into a locking hole 11 provided in the mounting member 1, and the tension arm 5 is rotated in the circumferential direction by the torsional force of the torsion coil spring 8. , belt tension is applied.

The structure of this torsion spring is the most characteristic part of the present invention, and will be described in detail below. FIG. 2 is a front view of the twisting spring 8 used in this embodiment. The torsion spring 8 has its strands 2
The cross section of wire 20 is square as shown in FIG. 3, and the wire 20 is covered with a resin layer 21 which is also square.

Here, it is preferable to use a highly elastic material such as rubber or urethane as the resin that covers the wire 20.

The coil spring 8 is shown in FIG. 1 described above with the resins 21 of the adjacent strands in contact with each other, or in other words, the spring is compressed in the longitudinal direction so that there is no gap. placed in position.

4 and 5 are front views of other embodiments of the spring, in which both ends are embedded in the resin 30 in FIG. 4 and one end is embedded in the resin 30 in FIG. It is of course possible to embed the spring in resin, as shown in Figure 4, even if the entire spring is buried, rather than just a portion as shown in Figure 5, but normally springs are In order to bias the arm in one direction, set it in a twisted state at an angle of about 15 to 45 degrees in advance, and adjust the total twist angle including the operation during installation.
The angle will be approximately 60 to 90 degrees, so care must be taken because if the entire body is buried, the resin will not be able to deform to follow the deformation of the spring and may break. Further, the spring can be used even if it has a spiral shape like a mosquito coil.

(Effects of the Invention) The autotensioner of the present invention replaces conventional damper members such as fluids by coating the wires of torsion springs with resin so that adjacent comrades are in contact with each other, or by encasing part or all of the spring in resin. By embedding the tension arm in the tension arm, strain energy is absorbed by the friction between the resins and the deformation of the resin itself, which has the effect of attenuating and converging the swinging of the tension arm. Therefore, there is no need to add a separate damper as in the conventional case, and the entire structure can be made compact.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of an autotensioner according to the present invention, FIG. 2 is a front view of a torsion spring used in an embodiment of the present invention, and FIG. FIG. 4 and FIG. 5 are front views of other embodiments of the torsion spring. a... Auto tensioner, S ₁ ... Tensioner shaft, 1... Mounting part, 2... Other parts, 5... Tension arm, 6... Idler pulley, 8...
Coil spring, 9... Stopper, 11...
Locking hole, 20... elemental wire, 21... resin, 30...
resin.

Claims (1)

[Claims] 1. A tension arm having an idler pulley rotatably fixed to one end thereof is rotatably fixed to a tensioner shaft provided on a mounting member for attaching the autotensioner to another member. An autotensioner comprising a torsion spring interposed between a tension arm and a tension arm, wherein the torsion spring has a wire coated with a resin, and the coated wires of adjacent wires are in contact with each other. Jonah. 2 A tension arm with an idler pulley rotatably fixed to one end is rotatably fixed to a tensioner shaft provided on a mounting member for attaching the autotensioner to another member, and the tensioner arm is rotatably fixed to a tensioner shaft provided on a mounting member for attaching the autotensioner to another member, and is mounted between the mounting member or the tensioner shaft and the tension arm. An autotensioner including a torsion spring, wherein at least a portion of the torsion spring is embedded in a resin layer.