JPH0430449Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a belt tensioner that applies tension to a belt suspended between a driving wheel and a driven wheel.

(Prior art and its problems) Conventionally, such a belt tensioner has
For example, there is one disclosed in Japanese Utility Model Application Publication No. 61-61357. This technique uses a tension coil spring as a spring that biases an idle roller (tension pulley) on one side of a belt wound between a driving wheel and a driven wheel.

However, in such a conventional belt tensioner, one end of the tension coil spring is hooked to the bracket on the side of the idle roller, and the other end is hooked to the shaft of a pin or bolt with a head embedded in the cylinder block. The head of the pin or bolt is used to prevent the other end of the tension coil spring from coming off, and to prevent the coil part of the tension coil spring from interfering with other members during vibration. Since it is necessary to cover the periphery of the coil part with rubber, there is a problem that the number of parts involved in supporting the tension coil spring is large, which increases the number of assembly steps, resulting in an increase in cost.

(Purpose of the invention) The present invention has been made by paying attention to such conventional problems, and allows torsion coil springs to be assembled easily and reliably, and reduces the number of parts involved in assembling the torsion coil springs. The purpose of the present invention is to provide a belt tensioner that requires fewer assembly steps and reduces costs.

(Means for solving the problem) The gist of the present invention to achieve this purpose is as follows:
A support shaft that is movable on a cylinder block and rotatably supports a tension pulley, and a support shaft that urges the tension pulley to come into contact with a belt suspended between a driving wheel and a driven wheel. A belt tensioner is provided with a tension spring, the biased support shaft is fixed to a cylinder block at a predetermined position, and the tension force is applied to the belt via a tension pulley, wherein the tension spring is a torsion coil spring. At the same time, a boss portion is provided protrudingly on the cylinder block, one end of the torsion coil spring is hooked to the boss portion, the coil portion is fitted onto the outer periphery of the boss portion, and the other end is integrally connected to the support shaft. The belt tensioner is characterized in that the other end is hooked to the bracket so as to press the belt from above.

(Function) In the belt tensioner, one end of the torsion coil spring is hooked to the boss portion of the cylinder block, and the coil portion is fitted to the outer periphery of the boss portion, thereby positioning the torsion coil spring in the left-right direction. By hooking the other end to the bracket so that the other end is pressed down from above by a bracket integrated with the support shaft, the other end is prevented from slipping upward.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

1 to 4 show an embodiment of the present invention, and FIG. 1 is a perspective view showing a timing belt transmission system of an automobile engine to which a belt tensioner according to the present invention is applied.

As shown in FIG. 1, a timing belt transmission system 1 includes a drive wheel 2 fixed to a crankshaft (not shown).
and a driven wheel 3 fixed to a valve drive camshaft (not shown), a timing belt 4, and a belt tensioner 5 that applies tension to the timing belt 4.
and an idle pulley 6.

As shown in FIGS. 2 to 4, the belt tensioner 5 includes a tension pulley 7, a support shaft 9 that rotatably supports the tension pulley 7 via a bearing 8, and a support shaft 9 that rotatably supports the tension pulley 7. The main components are a torsion coil spring 10 that biases the support shaft 9 in the direction of contacting the timing belt 4, and a boss portion 12 of a cylinder block 11 to which the torsion coil spring 10 is mounted.

As shown in FIGS. 2 and 4, the support shaft 9 is a cylindrical body whose lower end side is open, and the upper end wall thereof has a shaft extending in a direction substantially perpendicular to the contact surface between the tension pulley 7 and the timing belt 4. A long hole 9a is bored therein.
The lower end of the support shaft 9 is a seat surface 11b with a screw hole 11a formed in the cylinder block 11 (see Fig. 3).
The support shaft 9 is fixed on the seat surface 11b by passing the bolt 13 through the elongated hole 9a, screwing the threaded portion 13a into the screw hole 11a, and tightening the bolt 13 onto the seat surface 11b. Also, brackets 14, 1 are provided on both sides of the support shaft 9.
5 is fixed to the cylinder block 11, and the locking hole 14a of the bracket 14 is a protrusion 11c protruding from the cylinder block 11.
is fitted. As a result, when the bolt 13 is loosened, the support shaft 9 moves the bearing surface 11 by the amount of play between the elongated hole 9a and the shaft of the bolt 13 using the protrusion 11c as a fulcrum.
It is possible to swing on b.

As shown in FIGS. 2 to 4, the boss portion 1
2 is molded integrally with the cylinder block 11. Groove 1 formed in the center of boss portion 12
One end 1 of the torsion coil spring 10 is attached to the bottom 12b of 2a.
0a is hooked, and the coil portion 10b of the torsion coil spring 10 is fitted to the outer periphery 12c of the boss portion 12. The other end 10c of the torsion coil spring 10
consists of a horizontal portion 10d extending laterally from the upper end of the coil portion 10b, and a vertical portion 10e rising upward from the horizontal portion 10d. The vertical portion 10e is connected to the slot-shaped retaining hole 15a of the bracket 15.
is passed from below through the bracket 15.
The lower surface of the torsion coil spring 10 presses the horizontal portion 10d of the torsion coil spring 10 from above so that the torsion coil spring 10 does not come off upward.

In addition, as shown in FIGS. 1 and 4, the entire timing belt transmission system 1 consists of a cylinder block 1.
1 is covered by a cover 16 that is removably attached to 1.

The operation of the timing belt transmission system 1 having the above configuration will be explained below.

First, a procedure for assembling the timing belt transmission system 1, particularly the belt tensioner 5, will be explained.

The timing belt 4 is suspended around the driving wheel 2, the driven wheel 3, and the idle pulley 6, and the lower end of the support shaft 9, on which the tension pulley 7 and bearing 8 are mounted, is seated on the seat surface 11b of the cylinder block 11, and the bracket is placed. 14 into the protrusion 11c of the cylinder block 11, and pass the bolt 13 through the elongated hole 9a of the support shaft 9 to tighten the threaded portion 1.
3a is screwed into the screw hole 11a, and the bolt 13 is loosened so that the support shaft 9 can swing on the seat surface 11b using the projection 11c as a fulcrum. On the other hand, one end 10a of the torsion coil spring 10 is attached to the boss portion 1.
2, the coil portion 10b is fitted to the outer periphery of the boss portion 12, and the vertical portion 10e of the other end 10c is passed through the locking hole 15a of the bracket 15 from below. The assembly of the coil spring 10 is completed. At this time, the torsion coil spring 10 is positioned in the left-right direction because the coil portion 10b is fitted to the outer periphery of the boss portion 12, and the lower surface of the bracket 15 presses the horizontal portion 10d of the other end 10c from above. , the torsion coil spring 10 is prevented from coming off in the upward direction.

In this way, the torsion coil spring 10 is attached to the boss portion 1.
2 and the bracket 15, the support shaft 9 swings toward the timing belt 4 due to the biasing force of the torsion coil spring 10, and the tension pulley 7 presses the timing belt 4. Rotate the support shaft 9 at a position that applies appropriate tension to the timing belt 4.
is fixed on the seat surface 11b of the cylinder block 11 by tightening the bolt 13. In this way, the assembly of the timing belt transmission system 1 is completed.

The rotation of the drive wheel 2, which rotates in conjunction with the crankshaft, is transmitted to the driven wheel 3 via the timing belt 4, and the valve drive camshaft rotates.

In the above embodiment, the other end 10c of the torsion coil spring 10 extends from the upper end of the coil portion 10b, and this other end 10c is hooked to the bracket 15. If there is not a sufficient gap between the torsion coil spring 10 and the surface as shown in FIG.
b, and connect the other end to the bracket 1.
It can also be configured so that it passes through the hooking hole 15a of No. 5 from below and is hooked thereon.

Alternatively, the boss portion 12 may be shaped without the groove 12a, and a hook portion for hooking one end of the torsion coil spring 10 may be provided at the lower end of the outer periphery of the boss portion 12.

(Effects of the invention) As detailed above, according to the belt tensioner according to the invention, the cylinder block has a boss portion protruding from the cylinder block, one end of a torsion coil spring is hooked to the boss portion, and the coil portion is attached to the boss portion. The other end of the torsion coil spring is latched onto the bracket so that the other end of the torsion coil spring is held from above by a bracket that is fitted onto the outer periphery of the boss portion and is integral with the support shaft that rotatably supports the tension pulley. By hooking one end of the torsion coil spring to the boss part of the cylinder block and fitting the coil part to the outer periphery of the boss part, the torsion coil spring is positioned in the left-right direction, and the other end is integrated with the support shaft. By hooking the other end to the bracket so that the bracket presses it from above, the other end is prevented from coming off upward, so the torsion coil spring can be assembled easily and reliably. The number of parts and assembly man-hours involved in assembly can be reduced, and as a result, costs can be reduced.

[Brief explanation of the drawing]

1 to 4 show one embodiment of the present invention, in which FIG. 1 is a perspective view showing a timing belt transmission system of an automobile engine to which the belt tensioner according to the present invention is applied, and FIG. 2 3 is a plan view showing the main part of the cylinder block, and FIG. 4 is a sectional view taken along the line - in FIG. 2. 2... Drive wheel, 3... Driven wheel, 4... Tension belt (belt), 5... Belt tensioner,
7... Tension pulley, 9... Support shaft, 10...
Torsion coil spring, 10a...one end, 10b...coil part, 10c...other end, 11...cylinder block, 12...boss part, 12c...outer circumference, 15...
...Bracket.

Claims (1)

[Scope of utility model registration request] A support shaft that is movable on a cylinder block and rotatably supports a tension pulley, and a support shaft that urges the tension pulley to come into contact with a belt suspended between a driving wheel and a driven wheel. A belt tensioner is provided with a tension spring, the biased support shaft is fixed to a cylinder block at a predetermined position, and the tension force is applied to the belt via a tension pulley, wherein the tension spring is a torsion coil spring. At the same time, a boss portion is provided protrudingly on the cylinder block, one end of the torsion coil spring is hooked to the boss portion, the coil portion is fitted onto the outer periphery of the boss portion, and the other end is integrally connected to the support shaft. A belt tensioner characterized in that the other end is hooked to a bracket so as to press the belt from above.