JPH11148538A - Assembly device of toothed belt with pulley - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the service life of a belt by setting the pulley tooth number of a drive shaft to be different from that of a driven shaft, setting the compression ratio of a pulley groove part of larger tooth number to a belt tooth part to be smaller than that of the pulley groove part of smaller tooth number, setting the volume of the pulley groove part of smaller tooth number to be larger than that of larger tooth number. SOLUTION: The tooth number of a pulley 2 of a drive shaft 5 is smaller than that of the pulley 2 of a driven shaft 6. The compression ratio of the belt tooth part 8 to the pulley groove part 3 is (H-D)/Hx 100%, where H is the height of a belt tooth part 8, and D is the depth of a pulley groove part 3, the compression ratio on the pulley side of larger tooth number is smaller than that on the pulley side of smaller tooth number, and the belt tooth part 8 is appropriately compressed on the pulley side. The volume of the pulley groove part 3 on the pulley side of smaller tooth number is larger than that of the pulley groove part 3 of larger tooth number. The belt groove part 8 is easy compressive deformation, and difficult to generate heat. The service life of a belt can be increased by reducing the stress burden on the belt tooth part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus 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 in accordance with the number of pulley teeth. To reduce the load on the belt teeth, and to extend the life of the belt by maintaining the free compression deformation of the belt teeth by changing the pulley groove volume even if the number of pulley teeth changes. The present invention relates to a device for combining a toothed belt and a pulley.

[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 to prevent the tapping noise generated when the surface of the belt groove 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, the belt tooth. Partial compression allowance / H × 100 (%). This value is set to 1 to 20%, for example,
No. 9141.

[0004]

However, in the conventional apparatus, even if the number of pulley teeth mounted on the drive shaft is different from the number of pulley teeth mounted on the driven shaft, the compression ratio between the belt tooth portion and the pulley groove portion is reduced. The settings were 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 a 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. The initial tension of the belt is set small to reduce the axial load of a machine used such as a device, and even if the compression ratio of the belt teeth changes. An object of the present invention is to provide a combination device of a toothed belt and a pulley aiming at extending the life of a belt by maintaining free compression deformation of a belt tooth portion.

[0008]

That is, according to the first aspect of the present invention, a pulley having grooves and 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. By making the number of teeth of the pulleys mounted on the shaft and the driven shaft different, the compression ratio between the pulley groove portion on the pulley side having a large number of teeth and the belt tooth portion is made smaller than the compression ratio on the pulley side having a small number of teeth, In addition, the pulley groove capacity of the pulley having a small number of teeth is larger than the pulley groove capacity of the pulley having a large number of teeth.

That is, in the above-described apparatus for combining a toothed belt and a pulley, the compression ratio between the pulley groove portion on the pulley side having a large number of teeth and the belt tooth portion is smaller than the compression ratio on the pulley side having a small number of teeth. Since the belt teeth are appropriately compressed on the pulley side having a large number of teeth and the pulley side having a small number of teeth, it is possible to suppress an increase in belt tension and reduce the axial load of a machine used such as a device. This reduces the stress on the belt teeth and extends the life of the belt. In addition, since the belt teeth are appropriately compressed by the respective pulleys, the belt does not separate from the pulleys due to jumping of the belt during traveling, and noise during traveling is reduced. Furthermore,
Since the pulley groove volume on the pulley side with a large number of teeth is made larger than the pulley groove volume on the pulley side with a small number of teeth, the belt teeth on the pulley side with a small number of teeth can be compressed and deformed without restriction. . That is, even if the compression ratio between the belt teeth and the pulley changes, each belt teeth is compressed and deformed without restriction, and is less likely to generate heat.

[0010] The invention according to claim 2 of the present application resides in a combination device of a toothed belt and a pulley comprising two shafts, one driving shaft and one driven shaft.

According to a third aspect of the present invention, there is provided a combination device of a pulley and a toothed belt in which a pulley groove has a bottom surface of an arc formed by a radius of curvature having a starting point on a center line.

[0012]

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.

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 comprises 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 portion 8 has a cross-sectional shape shown in FIGS. According to this, the belt tooth portion 8 has a starting point at a point away from the center line of the belt tooth portion 8, and is a round tooth formed by an arc having an intersecting radius of curvature Rb.
Of course, in the present invention, the present invention is not limited to this, and it may be a round tooth composed of a part of an arc having a tooth width W as a radius from the starting point provided on the pitch line to the belt tooth part, It may be.

The raw rubber used for the tooth portion 8 and the back portion 11 is a heat-aging material 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 an RFL solution or the like which is a protective agent or an adhesive made 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 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
It has. The pulley groove 3a having a small number of teeth shown in FIG.
6, which is an arc of the bottom surface 17 for being formed from a radius of curvature R ₂ having a starting point 15 on the center line l. The boundary between the side surface 16 and bottom surface 17 are connected by an arc consisting of the radius of curvature R _4. Position of the radius of curvature R ₂ of the size and origin 15 with the origin 15 is determined according to the depth of the pulley. The pulley tip 18 is formed by an arc formed by a radius of curvature R ₃ having a starting point 19.

On the other hand, the pulley groove 3 on the pulley side having a large number of teeth
A is set so that the depth D is larger than the pulley groove 3a on the pulley side having a small number of teeth. That is, FIG.
As shown in the figure, 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 consists bottom surface 17 of the same arc as the arc of the side surface 16 formed from a radius of curvature R ₁ that has a starting point 15a to the top. Note that the pulley tip 18 has the same shape as the pulley shown in FIG.

As shown in FIG. 4, the shapes of the side surfaces 16 and the bottom surface 17 of the pulley groove portion 3A (dotted line) on the pulley side having a large number of teeth and the pulley groove portion 3a (solid line) on the pulley side having a small number of teeth are compared. In the pulley groove portion 3a on the pulley side where the number is small, the volume is reduced at the bottom surface 17, but the volume is reduced by the side surface 16.
The pulley groove portion 3a on the pulley side having a small number of teeth is larger than the pulley groove portion 3A on the pulley side having a large number of teeth. (Capacity of the pulley groove 3a on the pulley side with a small number of teeth) − (volume of the pulley groove 3A on the pulley side with a large number of teeth) = 0.1 to 10% of the volume of the pulley groove 3A.

Thus, when the pulley groove 3a on the pulley side having a small number of teeth meshes with the belt teeth 8, the belt teeth 8
Is easily compressed and deformed so as to occupy the space 21 of the boundary portion 20. Even if the compression ratio with the pulley changes, the belt teeth 8 can be compressed and deformed as little as possible, so that the belt teeth 8 are easily deformed by compression and hardly generate heat. The combination of the pulley groove portion 3A 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 does not need to be limited to the shape of the pulley groove portion. What is necessary is just to make it more than the volume of the pulley groove part of a side with many numbers.

As shown in FIGS. 2 and 3, the pulley groove 3 and the belt teeth 8 are fitted to each other.
Is greater than the depth D of the pulley groove 3, and the belt teeth 8 and the pulley groove 3 are in compression engagement. The compression ratio is calculated as belt tooth portion compression allowance / H × 100 (%).

Further, in the combination device of the present invention, the compression ratio between the pulley groove 3A on the side having a large number of teeth and the belt tooth 8 is determined by:
Another feature is that the compression ratio is smaller than the compression ratio between the pulley groove 3a and the belt tooth 8 on the side having a small number of teeth. Specifically, the compression ratio between the pulley groove 3a on the pulley side of the drive shaft 5 having a small number of teeth and the belt teeth 8 is:
Pulley groove section 3A on the pulley side with a large number of teeth in driven shaft 6
And the compression ratio of the belt tooth portion 8 to 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. 6, 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, the compression ratio when the pulleys 2 and 2 having 18 teeth are mounted on the drive shaft 5 and the driven shaft 6 is 10
It was set to 0, and the optimal compression ratio for pulleys having a different number of teeth was calculated. For example, in the case of 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, each pulley groove 3 meshing with the belt tooth 8 is formed. Each component X ₀ , X in the X-axis direction
₁ , X ₂ , X ₃ , and X ₄ were determined from the equation X _n = 100 cosnα with X ₀ = 100. That is, the sum 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 total component force in the X-axis direction at the other number of pulley teeth is also the sum of 18 pulley teeth (1151.
To approximate to 8), first, the component force X ₀ in the X-axis direction is calculated by a proportional calculation (100 × 18 / the number of pulley teeth to be used), and then each X ₁ is calculated using the formula X _n = X ₀ cosnα. ,
X ₂ , X ₃ , X ₄ and X _n were calculated. Table 1 shows the results. FIG. 8 is a plot of X ₀ in Table 1 and the number of pulley teeth, and shows the relationship between the compression ratio and the number of 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 the compression ratio (the belt tooth portion compression allowance /
(H × 100), the belt tooth portion compression allowance and the compression ratio are in a proportional relationship, and as a result, the component force X ₀ is proportional to the compression ratio.

[0027]

[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 if 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.

[0032]

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 on the pulley side having a large number of teeth and the pulley side having a small number of teeth are determined. Since it is changed appropriately, 1) the increase in belt tension can be suppressed to reduce the axial load, and 2) the stress load on the belt teeth can be reduced to extend the life of the belt.
3) The belt teeth are appropriately compressed by each pulley, so that the belt does not separate from the pulley due to jumping during running, and noise during running can be reduced. 4) The belt tooth has a compression ratio with the pulley. Even if the value changes, it can be compressed and deformed without restriction as much as possible, has the effect of being less likely to compress fatigue, and less likely to generate heat.

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

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

FIG. 5 is an enlarged view of a pulley groove 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 a drive shaft and a driven shaft.

FIG. 7 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. 8 shows the relationship between the compression ratio between the pulley groove portion and the belt tooth portion and the number of teeth of the pulley under a condition where the axial load becomes substantially constant.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Combination apparatus 2 Pulley 3 Pulley groove part 3a Pulley groove part on the pulley side with a small number of teeth 3A Pulley groove part on the pulley side with a large number of teeth 4 Pulley tooth part 5 Drive shaft 6 Follower shaft 7 Toothed belt 8 Belt tooth part 9 Belt groove part 15 Origin 16 Side 17 Bottom

Claims (3)

[Claims] 1. A pulley having grooves and teeth alternately mounted on a drive shaft and at least one driven shaft, and a toothed belt is hung over these pulleys, and the height of the belt teeth is adjusted by the pulley. In a combination device of a toothed belt and a pulley, which is larger than the depth of the groove portion and the belt tooth portion is compression-engaged with the pulley groove portion, the number of teeth of the pulleys mounted on the drive shaft and the driven shaft is made different. The compression ratio between the pulley groove portion on the pulley side with many teeth and the belt tooth portion is made smaller than the compression ratio on the pulley side with few teeth, and the pulley groove volume on the pulley side with few teeth has a large number of teeth. A combination device of a toothed belt and a pulley, characterized in that the volume of the pulley is larger than the volume of the pulley groove on the side. 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 pulley groove has a bottom surface of an arc formed by a radius of curvature having a starting point on the center line.