JPS6216521Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to a tension device for applying appropriate tension to a timing belt that transmits rotation to a camshaft located far from the crankshaft in, for example, an OHC engine. It is.

(Prior Art) As shown in FIG. 4, a conventional general timing belt tension device has a structure in which an eccentric cam 1 is directly fixed to a support member 5 by a bolt 4 passing through the eccentric cam 1. Since it is usually covered by the belt cover 8, it has the following drawbacks.

(1) When adjusting the tension, it was necessary to remove the belt cover or the opening/closing lid provided on the belt cover, which was inconvenient.

(2) After loosening the bolt and applying the appropriate tension to the belt by the biasing force of the elastic member,
When tightening a bolt, the tightening torque may be transmitted to the eccentric cam, causing the cam to rotate in the tightening direction of the bolt, making it difficult to adjust the tension appropriately.

In addition, as other prior art of this invention,
A tensioning device described in Japanese Patent No. 58-163744 has been proposed, but even with this structure, it is necessary to remove the belt cover when adjusting the tension, and the arrangement of the elastic member that applies tension to the belt is difficult. Since it is different from a conventional tension device, it has the disadvantage that a conventional tension device cannot be used.

(Problem to be solved) This idea was made in view of the above points, and it is possible to adjust the tension of the tension device without removing the belt cover or the opening/closing lid provided thereon.
Further, when tightening the bolt, the tightening torque is not transmitted to the eccentric cam, so that the appropriate tension can be applied to the belt as set, and vibration of the belt cover is also prevented.

(Means for Solving the Problems) The configuration of this invention for solving the above problems is that the timing belt cover is provided with an opening that communicates with the bolt hole, and the non-rotating member has a bolt insertion hole in the opening. The belt cover is fitted with a non-rotating member, and the eccentric cam is fixed from outside the belt cover with a bolt via a non-rotating member.

(Function) After loosening the bolt from the outside of the belt cover to make the eccentric cam rotatable and optimizing the tension on the belt by the biasing force of the elastic member, tighten the bolt to fix the eccentric cam together with the belt cover. Adjust the tension on the tension device.

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

FIG. 1 is a front view showing an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line -- in FIG. In these figures, reference numeral 1 denotes an eccentric cam around which a tension pulley 2 is rotatably mounted, and a mounting hole 3 for a stud bolt 4a is bored eccentrically from the center of the eccentric cam 1.

Reference numeral 5 denotes a support member such as an engine housing that supports the eccentric cam 1, and a mounting seat 5a for the eccentric cam 1 is protruded from the support member 5.

Reference numeral 6 denotes an elastic member for rotationally biasing the eccentric cam 1 toward the timing belt A side, in which a torsion coil spring is used.
One end of the coil spring 6 is fixed to the eccentric cam 1 and the other end to the support member 5 so as to rotationally bias the eccentric cam 1 toward the belt A side when the coil spring 6 is attached to the belt.

Reference numeral 7 denotes a hexagonal collar as a non-rotating member having a bolt insertion hole 7a, and this collar 7 is loosely inserted into the stud 4a and arranged between the head 4a and the eccentric cam 1. A belt cover 8 is attached to the support member 5 by bolts 9 on the outside of the timing belt A and the eccentric cam 1. An opening 8a corresponding to the hexagonal collar 7 is provided, and the opening 8a is fitted into the hexagonal collar 7. Next, the manner of adjusting the tension in the above embodiment will be explained based on FIG. 2.

With the engine stopped, loosen the nut 4b from the outside of the belt cover 8 to make the eccentric cam 1 rotatable, and the coil spring 6 biases the eccentric cam 1 toward the belt A to rotate, thereby optimizing the tension on the belt A. Thereafter, by tightening the nut 4b, the eccentric cam 1 and the hexagonal collar 7 of the belt cover 8 are integrally fixed to the mounting seat 5a of the support member 5, thereby adjusting the tension of the tension device. In addition,
When tightening the nut 4b, since the non-rotating hexagonal collar 7 is interposed between the nut 4b and the eccentric cam 1, the tightening torque does not act on the eccentric cam 1, and therefore the eccentric cam 1 is suitable for the belt A. It will be fixed at a position that applies a certain amount of tension.

FIG. 3 is a cross-sectional view showing another embodiment of this invention, which differs from the previous embodiment in that the stud bolt,
In order to replace the nut combination with bolts and improve the ease of assembling the belt cover, a hollow knock pin 10 is inserted between the mounting hole 1a and the bolt 4 to make it possible to clean up the bolt afterwards. A washer 11 is interposed between the hexagonal collars 7 to make it difficult to transmit the tightening torque of the bolt. Since the other configurations are the same as those of the previous embodiment, the same reference numerals as in FIG. 2 are used in the drawings.

(Effects of the invention) As explained above, this invention has the above-mentioned configuration, and therefore has the following effects.

(1) The tension of the tension device can be adjusted without removing the belt cover or the opening/closing lid provided thereon.

(2) When tightening bolts, the tightening torque is not transmitted to the eccentric cam, allowing the tension to be adjusted to the appropriate setting.

(3) Since the belt cover is fixed to the support member together with the eccentric cam, vibration of the belt cover is prevented and noise is reduced.

(4) It is economical and convenient because the conventional tension device can be used as is.

[Brief explanation of the drawing]

Fig. 1 is a front view showing an embodiment of the present invention, Fig. 2 is a sectional view taken along the - line in Fig. 1, Fig. 3 is a sectional view showing another embodiment of the invention, and Fig. 4 is a conventional general FIG. 2 is a cross-sectional view showing the structure of a typical tension device. 1... Eccentric cam, 2... Tension pulley, 3
...Bolt mounting hole, 4...Bolt, 4a...
Studded bolt, 4b... Nut, 5... Support member, 5a... Mounting seat, 6... Coil spring (elastic member), 7... Hexagonal collar (non-rotating member), 8... Belt cover, 8a... Opening , 9... retaining bolt,
10...Hollow knot pin, 11...Washer,
A...Timing belt.

Claims (1)

[Claim for Utility Model Registration] A tension pulley rotatably mounted around an eccentric cam having a mounting bolt hole is brought into rolling contact with a timing belt, and an appropriate tension is applied to the belt by an elastic member within the eccentric cam. In the tensioning device, an opening is provided in the timing belt cover that communicates with the bolt hole, a non-rotating member having a bolt insertion hole is fitted into the opening, and a bolt is inserted from outside of the belt cover through the non-rotating member. A timing belt tension device characterized by fixing a cam.