JPS6123707Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a belt tensioner that applies a constant tension to a power transmission belt.

In recent years, toothed belts have been increasingly used instead of chains to drive camshafts that are synchronized with the crankshaft, as the main stage for reducing the weight of automobiles. In this case, since this belt is used at high temperatures and with a lot of vibration, there is a risk that it will stretch or skip stitches during use, and if left as is, it will disrupt the timing and also cause noise. Become. For this reason, a belt tensioner is used to constantly apply a constant tension to the belt, making it taut.

Conventional belt tensioners are shown in Figures 1 and 2.
As shown in the figure, a rotating part 5 in which a pulley 4 is fitted to an outer ring 3 of a bearing consisting of an inner ring 1, a plurality of rolling elements 2, and an outer ring 3, and an adjustment bracket 6 for adjusting the mounting position of the rotating part 5. The end of the inner ring 1 is press-fitted into a press-fit hole 7 of a bracket 6, and a bolt hole 10 and a spring 13, which serve as a fulcrum for position adjustment, are connected to ears 8 and 9 formed in the bracket 6, respectively. A stop hole 11 is formed, and the bolt hole 10 is formed in the inner ring 1.
An arcuate long hole 12 having a center of curvature at is bored.

Then, the fixing bolts 14 are inserted into the arc-shaped elongated holes 12 of the inner ring 1, the mounting bolts 15 are inserted into the bolt holes 10 of the bracket 6, and each is tightened to a stationary member, for example, an engine block 16, so that the rotating parts 5 and The bracket 6 is fixed to an engine block 16, and a spring 13, which has one end locked to the engine block 16, is locked in a locking hole 11 of the bracket 6. When the fixing bolt 14 and the mounting bolt 15 are loosened, the rotating part 5 and the bracket 6 tilt around the bolt hole 10 due to the tensile force of the spring 13, and the rotating part 5 comes into pressure contact with the tightened belt 17. Apply a certain tension, and in this state, first tighten the fixing bolt 14, then tighten the mounting bolt 15, and then tighten the rotating part 5.
The tension of the tightened belt 17 can be adjusted by fixing it at the adjustment position.

In this way, the conventional belt tensioner easily adjusts the tension of the tightened belt and maintains the synchronization of power transmission, but since the position adjustment bracket 6 is attached to the rotating part 5, Due to its large external size, it is difficult to install it in a space-constrained area such as an engine room of an automobile, and it is not preferable in terms of weight reduction.

This invention was proposed in order to improve and eliminate the above-mentioned problems of the conventional belt tensioner, and by using a spring to serve both as a position adjustment bracket and as an elastic force to the rotating part, the belt tensioner can be tightened. The tensioner is made smaller and lighter, and the spring is placed outside to improve ease of assembly.

Examples of this invention will be described below with reference to the drawings.

As shown in FIGS. 3 and 4, the belt tensioner is composed of a rotating section 20 and a spring 22 that applies a certain elastic force to the rotating section 20 and applies appropriate tension to the tightened belt 21.

The rotating part 20 is composed of an inner member, for example, an inner ring 23, a plurality of rolling elements 24, and an outer member, for example, an outer ring 25. The outer circumferential surface of the outer ring 25 has a groove to ensure contact with the twisted belt 21. A pulley 26 wider than the outer ring 25 is fitted. The inner ring 23
is formed into a cylindrical body, and a position adjustment hole, for example, a long hole 28, for adjusting the position of the rotating part 20 is formed in the center part of the bottom wall part 27, and a hole 28 is formed in the circumferential surface on the opening side. An annular groove 29 is formed. long hole 2
A bolt 30 is inserted into this elongated hole 28 and tightened to a stationary member such as an engine block 31, thereby fixing the rotating part 20.

The spring 22 is configured such that both ends 33 and 34 expand in opposite directions using the wound fixed part 32 as a fulcrum, and one end 33 is extended,
The contact portion 35 is curved into an arc having a diameter smaller than the diameter of the inner ring 23 of the rotating portion 20 . This spring 22 is fixed by fitting a fixing part 32 into a knock pin 36 protruding from the engine block 31, and having the other end 34 engaged with a stopper 37 which also protrudes from the engine block 31, and the contact part 33 at one end 33. 35 is brought into contact with an annular groove 29 formed in the inner ring 23 to hold the inner ring 23, and the elastic force of the spring 22 applies a rotational moment about the knock pin 36 to the rotating part 20 to position it. Adjust and apply a predetermined tension to the tightened belt 21.

When bringing the contact portion 35 of the spring 22 into contact with the annular groove 29 of the inner ring 23, make sure that the arc-shaped elongated hole 28 formed in the inner ring 23 coincides with the circular arc centered on the knock pin 36 or the fixed portion 32 of the spring 22. Have them place and hold it. In order to facilitate the assembly of the circular ring 23 and the spring 22, as shown in FIG. The end portion 39 is bent toward the center of the arc, and when the contact portion 35 is brought into contact with the annular groove 29, the end portion 39
Fitting into the fitting hole 38 facilitates assembly.

The belt tensioner having the above configuration is installed by attaching the contact portion 3 of the spring 22 to the annular groove 29 of the inner ring 23.
5 are brought into contact with each other to integrate the rotating part 20 and the spring 22. Then, the fixing part 32 of the spring 22 is fitted into the knock pin 36, and the bolt 30 is inserted into the arc-shaped elongated hole 28 of the inner ring 23 to connect the rotating part 20 and the spring 22. 2
0 and spring 22 to the engine block 31. At this time, do not fully tighten the bolts 30, but leave them loosened. The other end 34 of the spring 22 is engaged with the stopper pin 37, and the elastic force of the spring 22 causes the rotary part 20 to rotate around the knock pin 36, and the pulley 26 is brought into pressure contact with the tightened belt 21 to apply a predetermined tension. In this state, the bolts 30 are fully tightened to firmly fix the rotating part 20 to the engine block 31 to complete the installation.

In this way, in the belt tensioner, the end portion 33 of the spring 20 holds the inner ring 23 of the rotating portion 20 while providing elasticity, and when adjusting the position, the knock pin 3 to which the fixing portion 32 of the spring 22 is attached is attached.
The position is adjusted by rotationally moving the rotating part 20 around 6, and the belt tensioner can be fixed by tightening the bolt 30 inserted into the elongated hole 28. There is no need for a bracket to provide this, making it small and lightweight.

In the above embodiment, one end 3 of the spring 22
3 to hold the inner ring 23 of the rotating part 20, but it is not necessary to hold the inner ring 23 of the rotating part 20. It is also possible to simply make one end 33 of the spring 22 contact the inner ring 23. In short, the rotating part 20 is held by the knock pin 36
It may be arranged so as to be rotatable around the center so that a rotational moment along that direction can be applied.

Further, the present invention is not limited to the above-mentioned embodiment, and the elongated hole 28, which is a position adjustment hole formed in the inner text material 23, is not limited to the center part of the bottom wall part 27.
It may also be formed at a position eccentric from the center. Furthermore, although the inner member 23 forms an inner ring by forming a raceway surface for the rolling elements 24 on its circumferential surface, a separate inner ring having a raceway surface may be attached thereto. Moreover, it goes without saying that the present invention can be modified not only in the above-described embodiments but also as desired within the scope of the gist of the present invention.

As explained above, this invention includes a cylindrical inner member that has a bottom wall at one end and can be fixed to a stationary member with a bolt inserted through a position adjustment hole formed in the bottom wall; In a belt tensioner that is rotatably attached to an inner member via a rolling element and constitutes a rotating part with an outer member that rotates in contact with the belt, a dowel pin is mounted on a stationary member outside the rotating part. A coil spring, which is bifurcated so that both ends expand in opposite directions, and has a winding part in the middle, is inserted into the knock pin, and one end of the coil spring is inserted into the inside of the rotating part. one end of the inner member is hooked to the outer peripheral surface of the inner member, and the other end is hooked to a stopper on a stationary member outside the rotating section, and the position adjustment hole of the inner member is shaped like an arc centered on the dowel pin. Since the hole is made of a long hole, the rotating part can be rotatably supported by the coil spring in the direction of belt tension application using the knock pin as a fulcrum, and it can have the same arm function as a conventional bracket. By loosening the fixing bolt of the member, the entire rotating part can be automatically rotated in the belt tensioning direction, allowing the original belt tensioning action to take place.In particular, it is possible to rotate the coil spring. Since it is placed outside and has one end hooked to the outer periphery of the inner member and the other end hooked to the stopper on the stationary member of the rotating member, both hooking portions are clearly visible from the outside. This makes it easy to assemble and lock the spring, significantly improving the ease of attaching the belt tensioner, and increasing the distance from the fulcrum to the point of action, so the product of the elasticity and the arm size allows the belt to tighten easily. Since tension can be applied, the elasticity can be set relatively small, and there is no restriction on the wire diameter, number of turns, etc. of the spring, and there is an advantage that there is a large degree of freedom in design.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional belt tensioner.
Figure 2 is a front view of the belt tensioner, Figure 3 is a front view of the belt tensioner.
The figure is a half-sectional view of the belt tensioner according to the present invention, and FIG. 4 is a front view of the belt tensioner.
FIG. 5 is a front view of main parts showing another embodiment. 20...Rotating part, 21...Kotukudo belt, 2
2... Spring, 23... Inner ring, 27... Arc-shaped long hole, 29... Annular groove, 20... Bolt, 35
...Contact part, 36...Knock pin.

Claims (1)

[Scope of utility model registration request] A cylindrical inner member has a bottom wall at one end and can be fixed to a stationary member with a bolt inserted through a position adjustment hole formed in the bottom wall, and a rolling element is connected to the inner member. In a belt tensioner that is rotatably mounted and constitutes a rotating part with an outer member that rotates in contact with the belt, a dowel pin is provided on a stationary member outside the rotary part, and both ends of the dowel pin are arranged in opposite directions. A coil spring has a bifurcated shape so as to spread out, and has a winding part in the middle, and the coil spring is inserted through the winding part, and one end of the coil spring is hooked to the outer circumferential surface of the inner member of the rotating part; The other end is hooked to a stopper on a stationary member outside the rotating part, and the position adjustment hole of the inner member is an arc-shaped elongated hole centered on the knock pin. Belt tensioner.