JPH0141964Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a timing belt with rubber ribs. In other words, a regular toothed belt (timing belt)
By providing a plurality of cog-shaped ribs having side surfaces with a constant friction coefficient along the longitudinal direction of the upper surface, the transmission force of the rib surface in a multi-axis transmission mechanism is improved, and even with the upper surface of the belt, it can be used as a timing belt with multiple surfaces. This invention relates to a timing belt with rubber ribs intended for practical use.

(Prior Art) Conventionally, as this type of belt, there is a ribbed timing belt in which a plurality of triangular protruding ribs are provided on the upper surface of an ordinary toothed belt along the longitudinal direction of the belt.

(Problem to be solved by the invention) In this known belt, the toothed surface is wrapped around a regular toothed pulley for synchronous transmission, while the ribbed surface on the upper surface is fitted with a ribbed pulley and It also has the function of driving. However, in this known belt, the ribs on the upper surface of the belt are normal straight ribs without cogs, so the contact area with the ribbed pulleys is large, and considerable high horsepower transmission can be expected. Therefore, it is not possible to wrap the belt around the ribbed pulley at a very large contact angle, and if the contact angle is increased, there will be problems in terms of the flexibility of the belt.

The present invention was devised in order to solve the problem in view of the above-mentioned actual situation.The belt according to this invention has tensile ropes buried in parallel on the lower surface of a stretch rubber layer. In a ribbed timing belt in which a toothed portion is formed in the belt width direction and a plurality of cog-shaped ribs are provided along the longitudinal direction of the upper surface of the stretchable rubber layer, the coefficient of friction (μ) of the side surface of the rib is a:c. ×d (full area of rib including groove),
When setting b: Substantially total lateral area of the rib excluding the groove, c: Length of the oblique side of the rib, d: Belt circumference at a position of 1/2 of the length of the oblique side of the rib, 0.15≦0.35×a- It is characterized in that b/b≦μ≦0.9, and the flexibility of the upper surface of the belt is improved by providing a group of grooves with a predetermined pitch on the rib portion of the upper surface of the belt and a group of cogs with a constant pitch on the rib portion. In addition, the purpose is to ensure that the sides of the rib part have a sufficient contact surface with the pulley to maintain a particularly high coefficient of friction, thereby making it possible to transmit high horsepower through the rib part as well. This is what I did.

Next, specific embodiments of the ribbed timing belt according to the present invention will be described with reference to the drawings.

(Example) Fig. 1 is a perspective view of a part of the ribbed timing belt according to the present invention, and 1 in the figure is made of polyester, polyamide (specifically, trade name: nylon), aromatic polyamide (specifically, trade name: Kevlar). A low-elongation, high-strength fiber tensile rope made of fiber, rayon, glass fiber, etc., including NR (natural rubber), CR (chloroprene rubber), NBR (nitrile rubber), IIIR (butyl rubber), SBR (styrene-butadiene). They are buried in parallel at the pitch line positions in the stretchable rubber layer 2 made of a single material such as rubber or a blend thereof. Reference numeral 3 denotes a toothed portion made of rubber of the same material as the stretchable rubber layer 2, and is provided integrally with the stretchable rubber layer 2 in raised ridges at a constant pitch on the lower surface of the stretchable rubber layer 2. The surface of the toothed portion 3 is coated with one or more layers of rubber, the warp being a crimped polyamide fiber yarn (specifically, a product name: nylon yarn) and the weft being a normal non-stretchable yarn. It is covered with a stretchable canvas 4.

On the other hand, the upper surface of the stretchable rubber layer 2 is provided with a plurality of grooves 7 made of the same material as the stretchable rubber layer 2 and the toothed portions 3, each having a trapezoidal cross section and having a constant pitch in the longitudinal direction of the belt. Cog-shaped ribs 5 are integrally provided on the surface of the ribs 5, and the surface of the ribs 5 is a bias canvas made of cotton threads for both warp and warp, a wide-angle canvas, or a rubberized elastic canvas made of the same material as the covering canvas of the toothed part 3. 6 is coated with one to multiple layers, and the rib 5
Rubber parts are exposed on both sides.

That is, both the lower surface toothed portion 3 and the upper rib 5 of the belt are of the low edge type. Unlike ordinary linear ribs, the ribs 5 of the belt of the present invention are cog-shaped ribs with grooves 7 at a constant pitch in the longitudinal direction of the rib, so when it is wound around a ribbed pulley, the flexibility is low. This is very good, but on the other hand, the contact area of the rib groove is reduced by 7, and the transmission force is reduced by that amount. The present invention aims to maintain a high coefficient of friction on the side surfaces of the ribs 5 and compensate for the decrease in the transmission force by limiting the length and width of the side surfaces of the ribs 5, more specifically, the area of the side surfaces, to a certain range. It is something.

The friction coefficient (μ) of the side surface of the substantial portion of the rib 5 will be explained below. The friction coefficient of the side surface of the rib 5 is (μ), the length of the oblique side of the side surface of the rib 5 is C as shown in Fig. 2, and 1/2 of the length c of the oblique side of the side surface of the rib 5 as shown in Fig. 3.
If the circumferential length of the belt is d, then the groove 7 of the rib
The total lateral area a of the rib including (hatched area) is c×
d, and if the substantially entire lateral area b of the rib excluding the groove 7 (hatched area), that is, the cog-shaped rib 5, then (μ) is 0.15≦0.35×a-b/b≦μ≦0.9. Must be included in the range. Here left side 0.35
xa-b/b needs to have a minimum value of 0.15; if the friction coefficient is less than 0.15, the friction coefficient of the side surface of the rib is too low and the transmission force will also decrease, so a and b are selected so that the friction coefficient is greater than this minimum value. Although the coefficient of friction (μ) of the rubber itself is normally higher than 0.15, in the belt of the present invention, the rib side area is reduced substantially by the groove portion 7 of the cog.

However, by optimizing the values of a and b, more specifically, when the value of a-b/b is usually in the range of 0.45-1.2, the coefficient of friction (μ) can be maintained in the range of 0.15-0.30. Also, the coefficient of friction (μ) of rubber is
The limit is 0.90, and anything over 0.90 is actually impossible to manufacture, and if the coefficient is too large, the belt will not be able to exhibit its full potential.

(Effects) As described above, the belt of the present invention is a ribbed timing belt in which a plurality of cog-shaped ribs are provided along the longitudinal direction of the upper surface of a conventional timing belt and have side surfaces with a high friction coefficient that ensure the above-mentioned numerical limitation. hand,
The toothed belt on the lower surface of the belt meshes with the toothed pulley to perform synchronous transmission, and the rib surface on the upper surface of the belt compensates for the decrease in the side area of the rib portion that occurs in the groove portion provided in the rib portion. By setting the ratio of the area of the real part to the defective part within a certain range, it is possible to achieve sufficiently efficient power transmission. Since the belt can be constructed from a homogeneous rubber material, it is possible to perform high-horsepower back drive using a ribbed pulley without impairing the flexibility of the belt. Further, this idea was developed by adding a large number of cogs on the ribbed surface. Instead of the ribbed pulley, synchronous transmission can be performed on the upper surface of the belt using a toothed pulley, i.e., synchronous transmission on both upper and lower surfaces as with a double timing belt, if necessary. In addition to the fact that it has good flexibility and flexibility, it is extremely suitable as a belt for automobiles and other general industrial belts, and it is possible to expand the range of its use.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view of a ribbed timing belt according to the present invention, FIG. 2 is an enlarged cross-sectional view of FIG. 1, and FIG. 3 is an enlarged side view of FIG. 1. In the figure, 1 is a tensile rope, 2 is a stretch rubber layer, and 3 is a tensile rope.
5 represents a toothed portion, 5 represents a cog-shaped rib, and 7 represents a groove portion.

Claims (1)

[Scope of Claim for Utility Model Registration] On the lower surface of the stretchable rubber layer in which tensile ropes are embedded in parallel, toothed sections are formed in the belt width direction at a constant pitch, and on the other hand, a plurality of teeth are formed along the longitudinal direction of the upper surface of the stretchable rubber layer. For a ribbed timing belt with a cog-shaped rib, the coefficient of friction (μ) on the side surface of the rib is
A timing belt with rubber ribs, characterized in that the timing belt is in the range of 0.15≦0.35×a-b/b≦μ≦0.90. However, a: c x d (total lateral area of the rib including the groove) b: Substantially the entire lateral area of the rib excluding the groove c: Length of the oblique side of the rib d: Belt circumference at the position of 1/2 of the length of the oblique side of the rib Long.