JPS5915780Y2 - toothed belt - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a toothed belt, and more particularly to a toothed belt that uses glass fiber as a tensile member, has low belt elongation, and has bending fatigue resistance.

Unlike flat belts and belts, toothed belts can provide reliable transmission without slipping, and compared to reliable transmission using gears or chains, they do not require lubrication, so the demand for them has increased rapidly in recent years. is increasing.

In particular, the advancement of this technology is remarkable in the transmission drive of overdrive camshafts (OHC) in automobiles.

However, in the case of such an OHC drive, since the toothed belt is used under high load and on multiple axes, the belt is subjected to bending fatigue and is stretched.

If a toothed belt used under such severe conditions is stretched by more than about 0.1%, it will not mesh well with the pulleys and will tend to cause a jumping phenomenon.

The behavior tendency of this toothed belt is influenced by the properties of the tensile material, namely elongation and flexural fatigue.

By the way, glass fiber rope is used as one of the tensile materials in Imada's toothed belt, which has high strength, elongation, and small temperature change.

For example, in the case of belts in automotive OHC drives, the fiberglass rope construction is typically ECG-150-3/
13. The number of first twists is 2.1 times/25mm, the number of first twists is 4.0 times/25mm, and the first and second twists are in opposite directions.

However, when running under conditions of high load and multiple axes of small-diameter pulleys as in the OHC drive described above, such glass fiber ropes are stretched, causing a decrease in belt tension.

There are various possible causes for this, but it has been found that one of them is related to the rope structure to some extent.

In this sense, the present invention focuses on the drawbacks of the above-mentioned rope structure, and uses a glass fiber rope having a rope structure with low rope elongation and bending fatigue as a tensile member to create a toothed belt with low elongation and low bending fatigue. The purpose is to provide the following.

That is, the present invention collects glass fiber strands, pre-twists them in the same direction as the final twist with a pre-twist coefficient of 0.4 or less, and collects them and ply-twists them with a pre-twist coefficient of 1.6 to 2.5. The purpose is to use the rope as a tensile member of a toothed belt.

Hereinafter, the toothed belt of the present invention will be explained in detail.

FIG. 1 partially shows a part of the toothed belt according to the present invention, and in the figure, 1 is a toothed belt, and 2 is a reinforcing cloth made of polyamide fiber or the like that covers the surface of the teeth of the belt. , 3 is a toothed part and an extension part made of a rubber elastic body, 4
is a tensile material made of glass fiber rope, which is a feature of the present invention.

FIG. 2 is a sectional view showing an example of the glass fiber rope 4 in FIG. 1, ECG-150-3/13, with a diameter of 9
μ alkali-free glass filament with a thickness of 15,000
Gather 3 strands 5 gathered in yards/pounds and pre-twist them in the direction of arrow A with a pre-twist coefficient of 0.4 or less to form a rope 6. Collect 13 of these strands 6 and twist in the same direction as the pre-twist. This is a rope obtained by ply-twisting A with a ply-twist coefficient of 1.6 to 2°5.

At this time, if the first twist is applied in the opposite direction, the first twist will be unraveled and the desired result will not be obtained.

Note that the twist coefficient is calculated as T-F=-IUT/28.7.

(D: total denier of the rope, T: number of twists per centimeter) In the above case, the number of ropes in each child rope 6 is 5 in addition to the 3 ropes mentioned above.
Although books are not inconceivable, considering the thickness of the strands and in terms of performance, three is the most advantageous and desirable number.

In addition, the number of bundled ropes 6 or the total number of strands in the rope configuration is determined by the thickness of the tensile rope, and the required number is selected depending on each case. Examples of the body include the above 13 strands or 39 strands.

However, it goes without saying that this is not necessarily fixed.

Next, examples and performance of a toothed belt using a rope having the above structure will be shown below.

Examples Each toothed belt was manufactured by embedding a nylon canvas as a cover and a glass fiber rope having the rope structure shown in Table 1 as a tensile member in rubber.

The obtained belt has a tooth pitch of 9.525 mm and a number of teeth of 140.
The belt width was 24.5 mm.

Next, this belt was attached to the running test machine shown in Fig. 3 (drive pulley A has 21 teeth, pulley B has 38 teeth, pulley C has 42 teeth, pulley D has 42 teeth, and F and E are tension pulleys). Temperature: 80°C1 Drive pulley A rotation speed: 450
A running test was conducted under the conditions of 25 kg of belt initial tension, and the change in belt tension after 100 hours, the belt elongation after 1000 hours of running, and the remaining strength after 1000 hours of running were measured.

The results were as shown in Table 2.

In addition, the relationship between the strength and twist coefficient of the belts with each rope configuration shown in Example 1 and Comparative Example 1 before running, and the two-axis vertical running test machine (the number of teeth of the drive and driven pulleys are both 18) The elongation of the belt after running for 20 hours was investigated under the conditions of an environmental temperature of 180° C., a drive pulley rotation speed of 360 rpm, and a shaft load of 100 kg, and the results shown in FIG. 4 were obtained.

E: Alkali-free glass C: Long fiber G: Filament diameter 9 μm50: Strand size 15,000 yards/lbs 3/13: 3 is the number of strands to be twisted for first twisting 13 is 3 strands for first twisting Table 2 After 100 hours 1000 hour run Tension change during 1000 hour run Bell after run Remaining after run (kg) To elongation (%) Strength Example 1 3 0.024 1400 Comparative Example 1 14 0.050 975 From the results shown in Table 2 and Figure 4 above, the toothed belt with the rope structure of the present invention has less elongation during running than conventional belts, and has a greater residual strength after running, so it is affected by bending fatigue. Even when used under severe conditions, the belt tension does not decrease, maintaining good performance for a long period of time, and it is confirmed that the belt is extremely useful.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of a toothed belt according to the present invention;
Figure 2 is a cross-sectional view of the tensile glass fiber rope of the same belt.
FIG. 3 is a layout of a running test machine for toothed belts, and FIG. 4 is a chart showing the relationship between rope twist coefficient, belt running elongation, and belt strength. 1...Toothed belt, 2...Reinforcement cloth, 3
. . . Tooth section and extension portion, 4 . . . Tensile body, 5 . . . Strand, 6 . . .

Claims (1)

[Scope of utility model registration request] For the tensile body of the toothed belt, three strands of glass fiber are collected and twisted in the same direction as the final twist with a first twist coefficient of 0.4 or less, and the required number of strands are collected to have a final twist coefficient of 1.6 to 1.6. 2
．． A toothed belt characterized by using a glass fiber rope made by ply-twisting the fiber rope.