JPH028128Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a timing belt pulley having an even number of teeth on its outer periphery that mesh with the timing belt. The present invention can be used, for example, in a pulley on the crankshaft side of a timing belt transmission mechanism that transmits the rotation of the engine crankshaft to a camshaft.

(Prior art and its problems) The timing belt transmission mechanism was developed in 1983-119310.
As an example is shown in the publication, timing marks are written on each of the driving pulley and the driven pulley, and timing marks on the belt side corresponding to these timing marks are also written on the timing belt, and timing marks on the pulley side are written on the timing belt. By meshing the timing belt with the pair of pulleys in a state where the timing mark on the belt side and the timing mark on the belt side coincide with each other, timing belt transmission is performed with accurate timing.

By the way, the crankshaft side pulley which is the drive side pulley described in the above publication is basically formed in a symmetrical shape as shown in Fig. 3, and it is easy to confuse the front and back sides when assembling it to the crankshaft. There is a problem. Conventional products have timing marks only on the front surface, so it is essential to check the front and back sides during assembly, which is the key to improving the efficiency of assembly work.

(Purpose of the invention) In view of the above, an object of the present invention is to provide a timing belt pulley that does not require checking the front and back sides during assembly, thereby improving the efficiency of assembly work.

(Structure of the invention) The present invention focuses on the fact that the crankshaft side pulley generally has an even number of teeth, and in this timing belt pulley, the center line is made to coincide with a predetermined tooth ridge or bottom of the teeth. A key groove or similar positioning engagement part is formed, and timing marks are provided on each of the front and back surfaces, and these timing marks have a symmetrical positional relationship with respect to a center line passing through the key groove or similar positioning engagement part. It is characterized in that it indicates the position of the tooth ridge or tooth bottom in the area.

(Embodiment) In the embodiment shown in FIGS. 1 to 3, the engine 1
The present invention is applied to a pulley A on the crankshaft side of a timing belt transmission mechanism that transmits the rotation of the crankshaft 2 to the camshaft 3.

A timing belt 5 meshes with the pulley A and a pulley 4 assembled to the camshaft 3, reducing the rotation of the crankshaft 2 to 1/2 and transmitting the rotation to the camshaft 3. Timing marks 6 and 7 are marked on the pulleys A and 4, respectively, and timing marks 8 and 9 are also marked on the timing belt 5. 10 is a tensioner.

Timing belt pulley A to which the present invention is applied
As shown in FIGS. 2 and 3, the belt is symmetrically formed on the front and back, and has an even number of teeth 11 on the outer periphery that mesh with the timing belt 5. Then, a key groove 13 is formed so that a predetermined tooth ridge 12 of the tooth 11 coincides with the center line M, and timing marks 6, 6 are provided on the front surface 14a and the back surface 14b, respectively. are located near the teeth 15a, 15b which are symmetrical with respect to the centerline M of the keyway 13. Incidentally, the angle θ between these gear teeth 15a, 15b and the center line M can be arbitrarily selected. In FIG. 1, 16 is a key.

It is preferable that the timing belt pulley A is manufactured by integrally molding a sintered alloy, thereby simultaneously forming a pair of concave timing marks 6, 6.
And the keyway 13 can be formed at an accurate position.

Thus, according to the above configuration, when the timing belt pulley A is assembled to the crankshaft 2, the position of the timing mark 6 can be made the same even when the timing belt pulley A is assembled with the front and back sides reversed.

The present invention can be configured in various ways other than those shown in the above embodiments. For example, as in the embodiment shown in FIG. 4, the key groove 13 is formed so that the predetermined tooth bottom 17 of the tooth 11 and the center line M coincide with each other, and timing marks are provided on each of the front surface 14a and the back surface 14b. 6 and 6 are tooth bottoms 18a and 18b which are in a symmetrical positional relationship with respect to the center line M of the keyway 13
(This may be the gear teeth 15a, 15b.) In addition, when the keyway 13 is formed so that the predetermined gear tooth 12 and the center line M coincide with each other, the front surface 14a and the back surface 14
The timing marks 6, 6 provided on each of the teeth b may be located near the tooth bottoms 18a, 18b which are symmetrical with respect to the center line M of the keyway 13. Furthermore, in place of the keyway 13, a fourth
As shown by the imaginary line in the figure, the positioning engagement portion 13a
It is also possible to apply the present invention to a timing belt pulley A having the following.

It goes without saying that the present invention can be applied to a pulley on the camshaft side of a timing belt transmission mechanism of an engine, if necessary, and can also be applied to pulleys for other timing belts.

(Effects of the invention) The present invention has the above-mentioned configuration, and when assembling a timing belt pulley to a shaft, it can be assembled without checking the front and back sides of the pulley, and the timing belt can be placed in the correct position regardless of whether it is front or back. Since marks can be placed, the efficiency of the assembly work can be improved.

[Brief explanation of the drawing]

Fig. 1 is a front view showing an embodiment of the present invention, Fig. 2 is a front view of the main part thereof, Fig. 3 is a central vertical sectional view of the main part, and Fig. 4 is a front view of another embodiment of the invention. FIG. 3 is a front view of main parts. 5...Timing belt, 6...Timing mark, 11...Teeth, 12...Predetermined tooth ridge, 13...
...Keyway, 13a...Positioning engagement part, 14a...
...Front surface, 14b...Back surface, 15a, 15b...Tooth ridge, 17...Predetermined tooth bottom, 18a, 18b...Tooth bottom, M...Center line.

Claims (1)

[Scope of utility model registration request] In a timing belt pulley having an even number of teeth on the outer periphery that mesh with the timing belt, a keyway or similar positioning engagement part is formed so that the center line coincides with a predetermined tooth ridge or bottom of the teeth. In addition, timing marks are provided on each of the front and back surfaces, and these timing marks indicate the position of the tooth ridge or tooth bottom that is symmetrical with respect to the center line passing through the keyway or similar positioning engagement part. A timing belt pulley characterized by: