JPH094685A - Combined device of toothed belt and pulley - Google Patents

Abstract

PURPOSE: To provide a combined device of a toothed belt and a pulley so as to extend life of a belt by setting an initial tension of the belt small, reducing an axle load of a using machine such as a device, and maintaining free compressive deformation of a belt teeth part even of a compression ratio of the belt teeth part changes. CONSTITUTION: This combined device 1 of a toothed belt and a pulley is provided with pulleys 2 alternately having pulley groove parts 3 and pulley teeth parts 4 fitted to a driving shaft 5 and at least one driven shaft 6 respectively, and a toothed belt 7 engaged with the pulleys. In this device, the number of teeth of pulleys fitted on the driving shaft 5 and the driven shaft 6 are made different from each other, a compression ratio of the pulley grooves to the belt teeth of pulley side with more teeth is made smaller than the compression ratio of the pulley grooves to the belt teeth of pulley with less teeth, and volume of the pulley grooves of the pulley with more teeth is made roughly the same or more than the volume of the pulley grooves of the pulley with less teeth.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combination device of a toothed belt and a pulley, and more specifically, the compression ratio between a belt tooth portion and a pulley groove portion is changed according to the number of pulley teeth, and the number of teeth is further changed. Even if the volume of the pulley groove is changed, the axial load of the machine used is reduced, the load on the belt teeth is reduced, and even if the compression ratio of the belt teeth changes, the belt teeth can be freely compressed and deformed. The present invention relates to a combination device of a toothed belt and a pulley aiming at extension of belt life by maintaining the above.

[0002]

2. Description of the Related Art In the present combination device of a toothed belt and a pulley, various drive devices have been proposed in which the side surface of the belt tooth portion is arcuate and the side surface of the pulley groove portion is also arcuate.
Among them, Japanese Examined Patent Publication No. 5-70735 and Japanese Examined Patent Publication No. 57-5.
The drive systems disclosed in Japanese Patent No. 1589 and Japanese Patent Publication No. 56-29141 have become mainstream today.

In these driving devices, in order to prevent a tapping noise generated when the belt groove surface having a large surface hardness and the pulley tooth surface come into contact with each other, the height of the belt tooth portion is set to the pulley groove portion. The depth is made larger than the depth, and the relatively flexible belt tooth portion is brought into contact with the pulley groove portion for compression engagement, thereby reducing noise during driving. That is, the bumper effect is applied to the belt teeth so as to absorb the energy at the time of collision. Usually, when the height of the belt tooth portion is H and the depth of the pulley groove portion is D, the compression ratio between the belt tooth portion and the pulley groove portion is calculated by (HD) / H. 1 to 20% is, for example, Japanese Patent Publication No. 56-291
No. 41 publication.

[0004]

However, in the conventional device, even if the number of teeth of the pulley mounted on the drive shaft is different from the number of teeth of the pulley mounted on the driven shaft, compression of the belt tooth portion and the pulley groove portion is performed. The ratios were set the same. The surface pressure per unit area between the pulley with a large number of teeth and the belt is smaller than the surface pressure between a pulley with a small number of teeth and the belt, and the compression of the belt tooth part fitted to the pulley with a large number of teeth. The strain was smaller than that of the belt tooth portion fitted in the pulley having a small number of teeth.

For example, if the compression ratio between the belt tooth portion and the pulley groove portion is adjusted to the pulley side having a small number of teeth, the belt tooth portion cannot be sufficiently compressed on the pulley side having a large number of teeth.
The belt was always lifted from the pulley, and not only the normal meshing condition expected for the tooth profile was not obtained, but also the belt sometimes jumped during running and sometimes separated from the pulley. The belt tension was increased to prevent this, but the belt was heavily loaded. On the contrary, when the compression ratio of the belt tooth portion and the pulley groove portion is adjusted to the pulley side having a large number of teeth, the belt groove surface and the pulley tooth surface abut on the pulley side having a small number of teeth, and a tapping noise is generated. .

Further, in the conventional driving device, the belt requires more tension than necessary and the axial load is excessive.

The present invention solves such a problem by reducing the initial tension of the belt to reduce the axial load of the machine used, such as an apparatus, and even when the compression ratio of the belt teeth changes. It is an object of the present invention to provide a combined device of a toothed belt and a pulley aiming at extension of belt life by maintaining free compression deformation of a belt tooth portion.

[0008]

That is, a feature of the present invention is that a pulley having alternating pulley groove portions and pulley tooth portions is mounted on a drive shaft and at least one driven shaft, respectively, and these pulleys are mounted. In the combination device of the toothed belt and the pulley, in which the toothed belt is hung on the belt, the height of the belt toothed portion is made larger than the depth of the pulley grooved portion, and the belt toothed portion is compressed and engaged with the pulley grooved portion, The number of teeth of the pulleys mounted on the shaft and the driven shaft is made different, and the compression ratio of the pulley groove part on the pulley side with many teeth and the belt tooth part is set to the compression ratio between the pulley groove part on the pulley side with few teeth and the belt tooth part. A combination device of a toothed belt and a pulley in which the volume of the pulley groove portion on the pulley side which has a smaller number of teeth and which is smaller than that of the ratio is about the same as or larger than the volume of the pulley groove portion on the pulley side which has a small number of teeth. A. The present invention also includes a combination device including two shafts, one drive shaft and one driven shaft, and a combination device in which the pulley groove portion has an arc bottom surface formed from a radius of curvature having an origin on the center line. .

[0009]

In the device for combining a toothed belt and a pulley according to the present invention, the compression ratio between the pulley groove portion on the pulley side having a large number of teeth and the belt tooth portion is determined by the pulley groove portion and the belt tooth portion on the pulley side having a small number of teeth. The compression ratio is smaller than that of the belt, and the belt teeth are properly compressed on the pulley side with a large number of teeth and the pulley side with a small number of teeth. Can be reduced. This reduces the stress burden on the belt teeth and extends the belt life. Further, since the belt tooth portion is appropriately compressed by each pulley, there is no separation from the pulley due to jumping of the belt during traveling, and noise during traveling is also reduced. Further, by setting the volume of the pulley groove portion on the pulley side having a large number of teeth to be substantially the same as or larger than the volume of the pulley groove portion on the pulley side having a small number of teeth, even if the compression ratio of the belt tooth portion to the pulley changes. It can be compressed and deformed as little as possible. The belt teeth are easily deformed by compression, and heat is less likely to occur.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 is a side view of a drive device for a toothed belt according to the present invention, FIG. 2 is a sectional view taken along the line AA on the pulley side having a small number of teeth in FIG. 1, and FIG. 3 is a pulley side having a large number of teeth in FIG. FIG.

In the toothed belt drive device 1 according to the present invention, pulleys 2 and 2 having alternating pulley groove portions 3 and pulley tooth portions 4 are mounted on a drive shaft 5 and a driven shaft 6, respectively, and a toothed belt 7 is provided. Is mounted on the drive shaft 5 and the driven shaft 6 and is mounted on the pulleys 2 and 2 having different numbers of teeth. The number of teeth of the pulley 2 mounted on the drive shaft 5 is smaller than that of the pulley 2 mounted on the driven shaft 6. Of course, the layout may be reversed.

The toothed belt 7 used in the present invention includes a plurality of belt tooth portions 8 and belt groove portions 9 alternately arranged along the length direction, a back portion 11 in which a core wire 10 is embedded, and a belt tooth portion 8. The surface of the belt groove portion 9 is covered with tooth cloth. The belt tooth portion 8 has a cross-sectional shape shown in FIGS. According to this, the belt tooth portion 8 is a circular tooth which has an origin at a point distant from the center line of the belt tooth portion 8 and is formed by arcs having intersecting radii of curvature Rb.
Of course, the present invention is not limited to this, and may be a round tooth formed by a part of an arc having a tooth width W as a radius from a starting point provided on a pitch line to a belt tooth portion, or a trapezoidal tooth. May be

The raw material rubber used for the tooth portion 8 and the back portion 11 is hydrogenated nitrile rubber, chloroprene rubber, chlorosulfonated polyethylene (CSM), alkylated chlorosulfonated polyethylene (ACSM) and other heat-resistant aging materials. Rubber having improved properties, natural rubber, styrene-butadiene rubber, nitrile rubber, etc. are used.

The core wire 10 is made by twisting filaments of E glass or high-strength glass having a diameter of 5 to 9 μm and treated with RFL liquid or the like which is a protective agent or an adhesive composed of a rubber compound. . Further, as an organic fiber, a filament of 0.5 to 2.5 denier of a para-aramid fiber (trade name: Kevlar, Technora) having a small elongation with respect to stress and a large tensile strength is twisted, and an RFL solution, an epoxy solution A twisted cord treated with an adhesive of an isocyanate solution and a rubber compound is used. However, the present invention is not limited to these.

The canvas used as the tooth cloth is 6 nylon, 66 nylon, polyester, aramid fiber or the like, and may be used alone or in a mixture. The composition of the warp (belt width direction) and weft (belt length direction) of the tooth cloth is also the filament yarn or spun yarn of the fiber,
The woven structure may be a plain weave, a twill weave, or a satin weave.
In addition, it is preferable to use a part of urethane elastic yarn having elasticity as the weft.

The pulley 2 used here has a belt tooth portion 8
And a pulley groove portion 3 and a pulley tooth portion 4 that mesh with the belt groove portion 9
It has. The pulley groove portion 3a having a small number of teeth shown in FIG. 4 is a side surface 1 formed of an arc or a substantially straight line.
6 and a bottom surface 17 of an arc formed by a radius of curvature R ₂ having a starting point 15 on the center line l. The boundary between the side surface 16 and the bottom surface 17 is connected by an arc having a radius of curvature R ₄ . The size of the radius of curvature R _{2 having} the starting point 15 and the position of the starting point 15 are determined according to the depth of the pulley. Further, the pulley tooth top portion 18 is an arc formed by a radius of curvature R ₃ having a starting point 19.

On the other hand, the pulley groove portion 3 on the pulley side having a large number of teeth
A is set so that the depth D is larger than that of the pulley groove portion 3a on the pulley side having a small number of teeth. That is, FIG.
As shown in Fig. 3, the pulley groove portion 3A on the pulley side having a large number of teeth has the same center line l as the pulley groove portion 3a on the pulley side having a small number of teeth.
It has a bottom surface 17 formed of the same arc as a side surface 16 of an arc formed by a radius of curvature R ₁ having a starting point 15a on the top. The pulley tooth tip 18 has the same shape as the pulley shown in FIG.

As shown in FIG. 4, when comparing the shapes of the side surface 16 and the bottom surface 17 of the pulley groove portion 3A (dotted line) on the pulley side with a large number of teeth and the pulley groove portion 3a on the pulley side with a small number of teeth (solid line), In the pulley groove portion 3a on the pulley side where there is little
The volume of the pulley groove portion 3a on the pulley side having a small number of teeth and the pulley groove portion 3A on the pulley side having a large number of teeth does not substantially change. Or more. However, in order to avoid compression fatigue of the belt tooth portion 8, it is preferable that the pulley groove portion 3a on the pulley side having a small number of teeth has substantially the same volume as the pulley groove portion 3A on the pulley side having a large number of teeth. Even if the pulley groove portion 3a on the pulley side having a small number of teeth is made larger than the volume of the pulley groove portion 3A on the pulley side having a large number of teeth, the difference is as small as 0.1 to 10% of the volume of the pulley groove portion 3a. .

As a result, when the pulley groove portion 3a on the pulley side having a small number of teeth meshes with the belt tooth portion 8, the belt tooth portion 8
The tip of the tooth is easily compressed, and is deformed so as to occupy the space portion 21 of the boundary portion 20. Since the belt tooth portion 8 can be compressed and deformed as little as possible without being restricted even when the compression ratio with the pulley is changed, the belt tooth portion 8 is easily compressed and deformed and is less likely to generate heat. The combination of the pulley groove portion 3A on the pulley side having a large number of teeth and the pulley groove portion 3a on the pulley side having a small number of teeth does not need to be limited to the shape of the pulley groove portion described above. Almost the same as the volume of the pulley groove on the side with fewer teeth,
Or more.

As shown in FIGS. 2 and 3, the fitting state of the pulley groove portion 3 and the belt tooth portion 8 is as shown in FIGS.
Is larger than the depth D of the pulley groove portion 3, and the belt tooth portion 8 and the pulley groove portion 3 are in compression engagement. The compression ratio is calculated by (HD) / H.

Further, in the combination device of the present invention, the compression ratio between the pulley groove portion 3A on the side having a large number of teeth and the belt tooth portion 8 is
Another feature is that the compression ratio between the pulley groove portion 3a having a small number of teeth and the belt tooth portion 8 is made smaller. Specifically, the compression ratio between the pulley groove portion 3a on the pulley side having a small number of teeth on the drive shaft 5 and the belt tooth portion 8 is
Pulley groove portion 3A on the driven shaft 6 having a large number of teeth on the pulley side
Is larger than the compression ratio between the belt tooth portion 8 and the belt tooth portion 8.

The relationship between the compression ratio and the number of pulley teeth is calculated by the following calculation. First, as shown in FIG. 6, a drive shaft 5 and a driven shaft 6 are attached with pulleys 2 and 2 having the same number of teeth and pitches, and a device with a toothed belt 7 is produced. The number of teeth of the pulley attached to No. 6 was changed, and the compression ratio was calculated so that the axial load was almost constant.

In this case, the compression ratio is 10 when the pulleys 2 and 2 having 18 teeth are mounted on the drive shaft 5 and the driven shaft 6.
The optimum compression ratio in a pulley having a number of teeth different from 0 was calculated. For example, in a pulley having 18 teeth, as shown in FIG. 7, based on the number of pulley teeth, each tooth angle (α), and the number of meshing teeth, the pulley groove portion 3 meshed with the belt tooth portion 8 is Each component force X ₀ , X in the X-axis direction
₁ , X ₂ , X ₃ , X ₄ are set to X ₀ = 100, and the formula X _n
= 100 cos α. That is, the total component force in the X-axis direction at the number of pulley teeth of 18 is 4 × (X ₁ + X ₂ + X
_{3 + X 4) + (X} n × 2) a = 1151.8.

The total of the component forces in the X-axis direction for other numbers of pulley teeth is the total of the number of pulley teeth 18 (1151.
In order to approximate 8), first, the component force X ₀ in the X-axis direction was calculated, and then each X ₁ , X ₂ , X ₃ , X ₄ , X _n was calculated. Table 1 shows the results. In addition, FIG. 8 shows X ₀ of Table 1.
And the number of pulley teeth are plotted to show the relationship between the compression ratio and the number of pulley teeth.

[0025]

[Table 1]

As is apparent from the above, under the condition that the axial load remains substantially constant even if the number of pulley teeth changes, the compression ratio also decreases exponentially as the number of pulley teeth increases. I understand.

Therefore, even when the number of pulley teeth mounted on the drive shaft 5 and the driven shaft 6 is different as in the combination device of the present invention, the characteristic relationship between the compression ratio and the number of pulley teeth is satisfied. Therefore, the compression ratio needs to be set. For example, in the drive device (device 1) in which the number of pulley teeth 18 and the number of pulley teeth 36 are combined, if the compression ratio with the belt tooth portion 8 that engages with the number of pulley teeth 18 is set to 7%, based on the above characteristic relationship The compression ratio with the toothed belt engaging the number of pulley teeth 36 is set to 3.5%. That is, the depth D of the groove portion of the pulley having 36 pulley teeth must be made larger than that of 18 pulley teeth.

In the drive device (device 2) in which the number of pulley teeth is 18 and the number of pulley teeth is 80, the number of pulley teeth is 18
When the compression ratio with the toothed belt engaging with the toothed belt is set to 7%, the compression ratio with the toothed belt engaging with the pulley tooth number 80 is set to 1.58%, and the depth of the groove portion of the pulley is set to D. Grows. The belt initial tension between these two devices 1 and 2 does not change, and the axial load is also substantially constant.

However, the number of pulley teeth is 18 and the number of pulley teeth is 36.
In the drive device in which the above combination, the initial belt tension and the axial load when both the compression ratios are set to 7% are larger than those of the device 1. Further, in the drive device in which the number of pulley teeth is 18 and the number of pulley teeth is 80, the belt initial tension and the axial load are further increased when the compression ratios are both set to 7%. When the compression ratio is set constant, the axial load increases linearly as the number of pulley teeth increases.

[0030]

As described above, in the combined device of the toothed belt and the pulley of the present invention, the compression ratio between the belt tooth portion and the pulley groove portion is appropriately adjusted on the pulley side having a large number of teeth and the pulley side having a small number of teeth. Since it is changed, 1) the increase of belt tension can be suppressed to reduce the axial load, 2) the stress load on the belt teeth can be reduced and the belt life can be extended, and 3) the belt teeth of each pulley can be changed. Since it is properly compressed, there is no separation from the pulley due to jumping of the belt at the time of running, and noise at the time of running can be reduced, and 4) The belt teeth are restricted as much as possible even if the compression ratio with the pulley changes. It has an effect that it can be deformed by compression without receiving it, is less likely to be fatigued by compression, and is less likely to generate heat.

[Brief description of drawings]

FIG. 1 is a side view of a combination device of a toothed belt and a pulley according to the present invention.

FIG. 2 is a sectional view taken along the line AA on the pulley side having a small number of teeth in FIG.

FIG. 3 is a sectional view taken along the line BB on the pulley side having a large number of teeth in FIG.

FIG. 4 is an enlarged view of a pulley groove portion on the pulley side having a small number of teeth.

FIG. 5 is an enlarged view of a pulley groove portion on the pulley side having a large number of teeth.

FIG. 6 is a side view of a drive device in which pulleys having the same number of teeth and the same pitch are mounted on the drive shaft and the driven shaft.

FIG. 7 is a schematic diagram showing a component force in the X-axis direction on each groove portion of a pulley having 18 teeth that meshes with a toothed belt.

FIG. 8 shows the relationship between the compression ratio between the pulley groove portion and the belt tooth portion and the number of pulley teeth under the condition where the axial load is substantially constant.

[Explanation of reference numerals] 1 combination device 2 pulley 3 pulley groove portion 3a pulley side pulley groove portion with a small number of teeth 3A pulley side pulley groove portion with a large number of teeth 4 pulley tooth portion 5 drive shaft 6 driven shaft 7 toothed belt 8 belt tooth Part 9 Belt groove part 15 Starting point 16 Side surface 17 Bottom surface

Claims (3)

[Claims] 1. A pulley having alternating pulley groove portions and pulley tooth portions is mounted on a drive shaft and at least one driven shaft, and a toothed belt is hung on these pulleys so that the height of the belt tooth portion is increased. In a combination device of a toothed belt and a pulley in which the belt tooth portion is compressed and engaged with the pulley groove portion by making the depth larger than the depth of the pulley groove portion, the number of teeth of the pulleys mounted on the drive shaft and the driven shaft is different, The compression ratio between the pulley groove part on the pulley side with a large number of teeth and the belt tooth part is made smaller than the compression ratio between the pulley groove part on the pulley side with a small number of teeth and the belt tooth part. A combined device of a toothed belt and a pulley, wherein the volume of the pulley groove portion is substantially equal to or larger than the volume of the pulley groove portion on the pulley side having a small number of teeth. 2. A combination device of a toothed belt and a pulley according to claim 1, comprising two shafts, one drive shaft and one driven shaft. 3. The combination device of a toothed belt and a pulley according to claim 1, wherein the pulley groove portion has a bottom surface of an arc formed by a radius of curvature having an origin on a center line.