JP2935960B2 - Combination device of toothed belt and pulley - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for combining a toothed belt and a pulley, and more particularly, to changing the compression ratio between a belt tooth portion and a pulley groove portion according to the number of pulley teeth. By improving the contact condition with the tooth tip,
The present invention relates to a combination device of a toothed belt and a pulley, which aims to reduce the axial load of a machine to be used and to reduce the load applied to the belt teeth to extend the life of the belt.

[0002]

2. Description of the Related Art In today's combination apparatus of a toothed belt and a pulley, various driving devices have been proposed in which the side surfaces of the belt teeth are formed in an arc shape and the side surfaces of the pulley grooves are formed in an arc shape.
Above all, Japanese Patent Publication No. 5-70735, Japanese Patent Publication No. 57-5
The drive system disclosed in Japanese Patent Publication No. 1589 and Japanese Patent Publication No. 56-29141 is the mainstream today.

[0003] In these drive devices, the height of the belt teeth is generally adjusted by the height of the pulley grooves in order to prevent the tapping noise generated when the surface of the belt grooves having a large surface hardness contacts the surface of the pulley teeth. Being larger than the depth, the relatively soft belt teeth contact the pulley grooves to compress and engage, thereby reducing noise during driving. That is, a bumper effect is provided so that the belt teeth absorb energy at the time of collision. Normally, 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 (H−D) / H × 100 (%), that is,
It is calculated by belt tooth part compression allowance / H × 100 (%) ,
When this value is set to 1 to 20%, for example,
No. 29141.

[0004]

However, in the conventional apparatus, 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, the compression of the belt tooth portion and the pulley groove portion is performed. The ratio was set the same. The surface pressure per unit area between the pulley and the belt having a large number of teeth is smaller than the surface pressure between the pulley and the belt having a small number of teeth, and the compression of the belt teeth fitted to the pulley having a large number of teeth is performed. The distortion was smaller than that of the belt teeth fitted on the pulley having a small number of teeth.

For example, when the compression ratio between the belt tooth portion and the pulley groove is adjusted to the pulley side having a small number of teeth, the belt tooth portion is not sufficiently compressed on the pulley side having a large number of teeth.
The belt always floats from the pulley, and not only does not have a normal meshing state expected from the tooth form, but also jumps during running and may be separated from the pulley. To prevent this, the belt tension was increased, but a heavy load was placed on the belt. Conversely, when the compression ratio between the belt tooth portion and the pulley groove portion was adjusted to the pulley side with a large number of teeth, the belt groove surface and the pulley tooth surface contacted on the pulley side with a small number of teeth, and a tapping sound was generated. .

[0006] Further, in the conventional driving device, an excessive tension is required for the belt, and the axial load is excessive.

The present invention has been made to solve such a problem, and changes the compression ratio between the belt teeth and the pulley groove in accordance with the number of pulley teeth. By improving the contact state, the initial tension of the belt is further reduced to reduce the axial load of the machine used, such as the device, and to reduce the load on the belt teeth and extend the life of the belt. A combination device with a pulley is provided.

[0008]

That is, a feature of the present invention is that a pulley having pulley grooves and pulley teeth alternately is mounted on a drive shaft and at least one driven shaft, respectively. A toothed belt and a toothed belt, the height of which is greater than the depth of the pulley groove, and the belt tooth is compression-engaged with the pulley groove. The number of teeth of the pulleys mounted on the shaft and the driven shaft is made different, and the compression ratio between the pulley groove and the belt teeth on the pulley with more teeth is smaller than the compression ratio on the pulley with fewer teeth. In the combination device of belt and pulley. The present invention also includes a combination device including two shafts of one drive shaft and one driven shaft, and a combination device that compresses and engages a raised portion provided on the bottom surface of a pulley groove with a belt tooth portion.

[0009]

In the apparatus 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 compared with the compression ratio on the pulley side having a small number of teeth.
As the number of pulley teeth increases, the pressure
Reduce the reduction ratio and change the shaft load even if the number of pulley teeth changes.
Can be avoided. That is, it is possible to reduce the axial load of the machine used, such as the device, by suppressing the increase in the belt tension. This reduces the stress on the belt teeth and extends the life of the belt. Ma
In addition, 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 reduced. Further, the raised portion provided on the groove bottom surface of the pulley groove portion is compression-engaged with the belt tooth portion, so that the tooth portion of the belt is easily deformed, and the same compression ratio can be obtained with a small load. Can be reduced.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 is a side view of the toothed belt driving device according to the present invention, FIG. 2 is a sectional view taken along the line AA of FIG. 1 on the pulley side having a small number of teeth, and FIG. FIG. 4 and FIG.
FIG. 5 shows another meshing state of the toothed belt and the pulley on the pulley side having a small number of teeth, and FIGS. 5 and 7 show another modified example corresponding to FIG. ,
Fig. 7 shows a meshing state between the toothed belt and the pulley on the pulley side having a large number of teeth.

In the toothed belt driving device 1 according to the present invention, pulleys 2, 2 having pulley grooves 3 and pulley teeth 4 alternately are mounted on a drive shaft 5 and a driven shaft 6, respectively. Are mounted on pulleys 2 and 2 having different numbers of teeth mounted on the drive shaft 5 and the driven shaft 6. The number of teeth of the pulley 2 mounted on the drive shaft 5 is smaller than the number of teeth 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 has a plurality of belt teeth 8 and belt grooves 9 alternately arranged along the length direction, a back 11 having a core wire 10 embedded therein, and a belt tooth 8. The surface of the belt groove 9 is covered with a tooth cloth. The belt tooth 8 has a trapezoidal cross section as shown in FIGS. 2 to 5, or an intersecting radius of curvature having two starting points in the belt tooth 8 as shown in FIGS. A tooth formed from the side wall and the flat tooth tip from the arc of the circle may be used. Needless to say, the toothed belt may be a toothed belt usually called STPD, and may be a round tooth formed by a part of an arc having a radius equal to the tooth width W of the belt tooth portion 8 from a starting point provided on the pitch line. The present invention is not limited thereto, and may be a round tooth formed of an arc of one radius of curvature having a starting point inside the belt tooth portion 8 on the center line of the belt tooth portion 8 called HTD.

The raw rubber used for the tooth portion 8 and the back portion 11 is heat aging such as hydrogenated nitrile rubber, chloroprene rubber, chlorosulfonated polyethylene (CSM), and alkylated chlorosulfonated polyethylene (ACSM). Rubber with improved properties, natural rubber, styrene-butadiene rubber, nitrile rubber and the like are used.

The core wire 10 is obtained by twisting filaments of 5 to 9 μm of E glass or high-strength glass and treating them with a rubber compound protective agent or an RFL liquid as an adhesive. . 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 combination. The configuration of the warp (belt width direction) or the weft (belt length direction) of the tooth cloth is also a filament or spun yarn of the fiber,
The woven structure may be any of a plain woven fabric, a twill woven fabric, and a satin woven fabric.
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 8
Pulley groove 3 and pulley tooth 4 that mesh with belt groove 9
The pulley groove 3 has a trapezoidal groove as shown in FIGS. 2 and 3, or a groove formed from a circular arc-shaped side wall and a flat groove bottom as shown in FIGS. It consists of a groove with the groove bottom as one arc,
There is no particular limitation.

Further, as shown in FIGS. 4 to 7, the groove bottom of the pulley groove 3 may be partially raised in an arc shape, and the raised portion 13 may be engaged with the belt tooth 8 in compression. Since the belt tip 12 is easily deformed and can obtain the same compression ratio with a small load, the axial load can be reduced. The outer shape of the raised portion 13 need not be limited to an arc, but may be a curve.

As shown in FIGS. 2 to 7, the fitting state between the pulley groove portion 3 and the belt tooth portion 8 is such that the height H of the belt tooth portion 8 is larger than the depth D of the pulley groove portion 3, The belt teeth 8 and the pulley groove 3 are in compression engagement. The compression ratio is (H−D) / H × 100 (%), that is, the belt tooth portion compression
It is calculated by the following formula: H / 100 × (%) . The pulley groove 3
Is a dimension from the tip of the raised portion 13 to the outer peripheral surface when the raised portion 13 is provided on the bottom surface of the groove.

Thus, in the combination device of the present invention, the compression ratio between the pulley groove portion 3 on the pulley side having a large number of teeth and the belt tooth portion 8 is determined by comparing the compression ratio between the pulley groove portion 3 on the pulley side with a small number of teeth and the belt tooth portion 8. One of the features is that the compression ratio is smaller than the compression ratio. Specifically, the compression ratio between the pulley groove portion 3 on the pulley side with a small number of teeth and the belt tooth portion 8 of the drive shaft 5 is smaller than the pulley groove portion 3 on the driven shaft 6 with a large number of teeth and the belt tooth portion 8. Is larger than the compression ratio.

The relationship between the compression ratio and the number of pulley teeth is calculated by the following calculation. First, as shown in FIG. 8, pulleys 2 and 2 having the same number of teeth and pitch are mounted on the drive shaft 5 and the driven shaft 6, and a device is mounted on which a toothed belt 7 is hung. The compression ratio was determined by changing the number of teeth of the pulley attached to No. 6 such that the axial load was substantially constant.

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

The sum of the component forces in the X-axis direction at other numbers of pulley teeth is the sum of 18 pulley teeth (1151.
To approximate the 8), first calculates the component force X ₀ in the X-axis direction
And, each of _X 1 using the subsequent equation _X n _{= X} 0 _COSnα,
X ₂ , X ₃ , X ₄ , and _Xn were calculated. Table 1 shows the results. Further, in FIG. 10 plots the X ₀ and pulley number of teeth of Table 1 shows the relationship between the compression ratio and the pulley teeth. That is, the component force X _0, since the belt tooth portion undergoes compressive deformation, the belt tooth portion compression allowance in proportion to the component force X ₀ changes. Here, the definition of compression ratio (the belt tooth portion compression allowance / H × 100), since the compression ratio and the belt tooth portion compression allowance is proportional, resulting component force X ₀ and the compression ratio are proportional.

[0023]

[Table 1]

From this result , it is understood that the compression ratio decreases exponentially as the number of pulley teeth increases under the condition that the axial load becomes substantially constant even if the number of pulley teeth changes.

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. It is necessary to set the compression ratio so that For example, in the driving 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 characteristic relationship, The compression ratio with the toothed belt engaged with the number 36 of pulley teeth is set to 3.5%. That is, the depth D of the groove portion of the pulley having 36 pulley teeth must be larger than that having 18 pulley teeth.

Further, in the driving device (device 2) in which the number of pulley teeth 18 and the number of pulley teeth 80 are combined, the number of pulley teeth 18
When the compression ratio with the toothed belt engaged with the pulley teeth is set to 7%, the compression ratio with the toothed belt engaged with the number of pulley teeth 80 is set to 1.58%, and the depth of the groove portion of the pulley is set to D. Becomes larger. The initial belt tension of the two devices 1 and 2 does not change, and the axial load becomes substantially constant.

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

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to specific embodiments. Examples 1 and 2, Comparative Example 1

A pulley having 60 teeth (60S8M0)
150B) and a pulley with 18 teeth (18S8M0)
150B), and the tooth form is STPD, the height of the belt teeth is 3 mm, the number of teeth is 89, and the belt width is 10 m.
m, a toothed belt having a tooth pitch of 8 mm was wound around, the moving shaft was moved to fix the distance between the shafts at 191.2 mm, and the axial load was measured with a tension meter.

In the pulley having 18 teeth, the depth D of the pulley groove is set to 2.85 mm and the compression ratio is set to 5%. On the other hand, in the pulley having 60 teeth, the depth of the pulley groove is set to D. 2.91 mm (compression ratio 3%), 2.96 m
m (compression ratio: 1.5%), and the axial load in this case was measured. The results are shown in Table 2 and FIG. From the results of the compression ratio and the number of pulley teeth in Table 1, the number of teeth is 1
If the compression ratio of the pulley in No. 8 is set to 5%, the compression ratio of the pulley having 60 teeth has an optimum value of 1.5%.

[0031]

[Table 2]

From these results, by changing the depth D of the pulley groove portion according to the number of pulley teeth, the axial load is reduced, and as a result, an increase in belt tension can be suppressed, and the life of the belt is expected to be prolonged.

[0033]

As described above, in the apparatus for combining a toothed belt and a pulley according to 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. 1) The increase in belt tension can be suppressed to reduce the axial load. 2) The stress on the belt teeth can be reduced to extend the life of the belt. Is properly compressed, the belt does not separate from the pulley due to jumping during running, and noise during running can be reduced. 4) The raised portion provided on the bottom of the pulley groove is formed by the belt teeth and the compression member. Therefore, the belt tip is easily deformed, and the same compression ratio can be obtained with a small load, so that the axial load can be further reduced.

[Brief description of the 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 of FIG. 1 on a pulley side having a small number of teeth.

FIG. 3 is a BB diagram of the pulley side having a larger number of teeth in FIG.
It is sectional drawing.

FIG. 4 is a sectional view of another embodiment corresponding to FIG. 2, showing a meshing state between the pulley-side toothed belt and the pulley having a small number of teeth.

FIG. 5 is a sectional view of another embodiment corresponding to FIG. 3, in which the toothed belt on the pulley side having a large number of teeth is engaged with the pulley.

FIG. 6 is a sectional view of still another embodiment corresponding to FIG. 2, showing a meshing state between the pulley-side toothed belt having a small number of teeth and the pulley.

FIG. 7 is a sectional view of still another embodiment corresponding to FIG. 3, showing a meshing state between the pulley-side toothed belt having a large number of teeth and the pulley.

FIG. 8 is a side view of a drive device in which pulleys having the same number of teeth and pitch are mounted on a drive shaft and a driven shaft.

FIG. 9 is a schematic diagram showing a component force in the X-axis direction for each groove of a pulley having 18 teeth meshed with the toothed belt.

FIG. 10 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 that the axial load becomes substantially constant.

FIG. 11 shows the relationship between the shaft load and the compression ratio when the distance between the shafts is constant and the depth D of the pulley groove of one pulley is changed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Combination apparatus 2 Pulley 3 Pulley groove part 4 Pulley tooth part 5 Drive shaft 6 Follower shaft 7 Toothed belt 8 Belt tooth part 9 Belt groove part 12 Belt tip part 13 Ridge part

Claims (3)

(57) [Claims] 1. A pulley having pulley grooves and pulley teeth alternately mounted on a drive shaft and at least one driven shaft, a toothed belt is suspended over these pulleys, and the height of the belt teeth is increased. Is larger than the depth of the pulley groove portion, and in a combination device of a pulley and a toothed belt in which the belt tooth portion is compression-engaged with the pulley groove portion, the number of teeth of the pulley mounted on the drive shaft and the driven shaft is different. A combination device of a toothed belt and a pulley, wherein a compression ratio between a pulley groove portion on a pulley side having a large number of teeth and a belt tooth portion is smaller than a compression ratio on a pulley side having a small number of teeth. 2. The combination device according to claim 1, comprising two shafts, one driving shaft and one driven shaft. 3. The combination device according to claim 1, wherein the raised portion provided on the groove bottom surface of the pulley groove portion is compression-engaged with the belt tooth portion.