JPS61112842A - Toothed belt type transmission device - Google Patents

Abstract

PURPOSE:To reduce impulse noise which arises upon engagement between the tooth section of a toothed belt and the tooth section of a pulley, by providing such an arrangement that a part of root of each tooth in the toothed belt is made in compressive contact with the tip of each tooth of the pulley with a suitable compressive margin. CONSTITUTION:There are provided a toothed belt 1 having teeth arranged at predetermined pitches in the longitudinal direction of the belt 1, and at least two pulleys 2 engaged with the toothed belt 1. The height HB of teeth of the belt 1 is set to be greater than the depth HP of groove in each pulley, a projection 13 is formed in the root 110 of each belt tooth 11 in at least one part thereof in the which-wise direction perpendicular to the longitudinal direction of the belt. This porjection 13 is arranged such that it is made in compressive contact with the tip of each tooth on each pulley with a suitable compressive margin upon engagement between the belt and the pulley.

Description

[Detailed description of the invention] (Technical field) The present invention relates to a transmission device using a toothed belt, and particularly to a transmission device using a toothed belt.

The present invention relates to a toothed belt transmission device capable of reducing noise during running over a long period of time and improving belt stiffness.

(Prior Art) Toothed belts generally generate less noise when running than transmission means such as chains or gears.

However, the noise generated during high-speed driving cannot be ignored. For example, a tooth bottom portion 301 of a belt 300 of a conventional toothed belt transmission as shown in FIG. 11 is directly connected to a tooth top portion 401 of a pulley 400 made of a hard material such as metal or resin. mesh. The belt tooth bottom portion 301 is made of a rubber layer in which a highly rigid core wire 303 such as a steel cord or a glass cord is embedded, and a canvas such as nylon that covers this layer.

The contact between the belt tooth bottom 301 and the pulley tooth top 401 is as follows.

Therefore, it becomes a collision between rigid bodies. Also, belt 30
0 runs in polygonal behavior. therefore.

Vibrations occur in the belt 300. As the device is driven at high speed, its vibrations become more intense, eventually leading to generation of unpleasant noise due to high frequencies caused by resonance. Also,
In this device, the canvas on the surface of the belt tooth base 304,
Alternatively, the belt tooth bottom portion 3 in contact with the pulley tooth top portion 401
The canvas on the surface of 01 is easily damaged and cracks gradually occur. This creates a problem in that the cracks develop in the belt rubber layer and cause the belt 300 to break. This cracking of the canvas of the dedendum portion 304 occurs because the transmitted load applied to the side surface of the belt tooth 302 repeatedly acts on the dedendum portion canvas as tensile stress. Cracks in the canvas of the belt tooth bottom portion 301 are due to surface pressure and bending fatigue when the belt tooth bottom portion 301 and the pulley tooth top portion 401 come into contact with each other in a collisional manner.

In order to reduce the above noise, as shown in Fig. 12,
The tooth height of the belt 500 is made larger than the groove depth of the pulley 600 to bring the belt tooth tip 50I' into contact with the pulley groove bottom 602. (Tokuko Sho 56-291
Publication No. 41). According to this device, the polygonal behavior of the belt 500 is slightly reduced, and since the belt tooth tips 501 buffer the energy at the time of impact between the belt 500 and the pulley 600, a certain degree of sound reduction effect can be obtained. However, the belt tooth bottom 502 and the pulley tooth top 601
Since there is still direct collision with the vehicle, the buffering effect is insufficient and the impact noise is not eliminated. If the belt tooth height is made larger than the pulley groove depth, the surface pressure on the belt tooth tip 501 will become extremely large, accelerating belt wear in that area, and the Bel) 500 will not be able to maintain sufficient durability. It disappears. Therefore, a satisfactory sound reduction effect cannot be obtained with this method.

Another noise reduction side stop is as shown in FIG.

A toothed belt transmission device has been proposed in which a protrusion 702 is provided on the tooth bottom 701 at an intermediate position between the teeth of the belt 700, and the protrusion 702 has a buffering effect on the pulley 800 (Japanese Patent Laid-Open No. 58 -137639). but.

In this device, the surface pressure at the belt tooth bottom 701 is concentrated on the protrusion 702, so that the protrusion 702 is severely worn.

Therefore, the sound reduction effect cannot be maintained for a long period of time. Moreover, the tension of the belt 700 decreases due to wear of the protrusion 702. An abnormal meshing occurs due to a change in the belt pitch line on the pulley 800.

The life of Belt Flow 0 itself will be shortened. In this device.

Furthermore, due to the shape of the belt, the polygonal behavior of the belt tends to be strengthened, and belt noise cannot be fundamentally solved.

(Objective of the Invention) An object of the present invention is to provide a toothed belt transmission device that can reduce the impact noise generated when the flat surface of the bottom of the belt tooth and the top of the tooth of the pulley mesh, and can maintain the sound reduction effect for a long period of time. It is about providing. Another object of the present invention is to provide a toothed belt transmission device which prevents cracking of the belt reinforcing member and has excellent durability by alleviating stress concentration at the belt tooth bottom plane part and the belt tooth root part. It is in.

(Structure of the Invention) The device of the present invention is a toothed belt transmission device comprising a toothed belt having teeth at a partial pitch in the longitudinal direction of the belt and at least two pulleys meshing with the toothed belt. When the belt meshes with the pulley, at least a portion of at least one of the root portions of each of the belt teeth is configured to come into compressive contact with the tooth tip portion of the pulley with an appropriate compression margin, thereby achieving the above-mentioned purpose. is achieved.

The device of the present invention is characterized in that the collision between the belt and the pulley when they engage is effectively damped by the compressive contact between the root of the belt and the tip of the pulley. Therefore, the impactful contact between the belt tooth bottom plane part and the pulley tooth top part is alleviated, resulting in a significant sound reduction effect. This buffering action relieves the stress concentration caused by the pulleys on the belt dedendum and root plane, and significantly improves the belt durability.

(Example) The present invention will be described below with reference to examples.

As shown in FIGS. 1 to 3, the transmission device of the present invention includes a toothed belt 1 having teeth at some pitches in the longitudinal direction of the belt.
and at least two pulleys 2 that mesh with the toothed belt 1. The height H8 of the belt teeth 11 is set larger than the depth H2 of the pulley groove 22. A protrusion 13 is provided in a portion of the root portion 110 of each belt tooth 11 in the tooth width direction perpendicular to the belt longitudinal direction.

When the belt 1 engages with the pulley 2, the pulley tooth tip 21
0 with an appropriate compression margin. The shape is particularly limited to 1 if it is a shape that can maintain a sufficient degree of freedom of compressive deformation in contact with the pulley tooth tip 210.
It is not limited.

The compression margin of the protrusion 13 is appropriately set depending on the shape, size, material, speed of power transmission, belt tension, etc. of the belt 1 and pulley 2 used. The maximum compression amount is 1% to 10% of the belt tooth height H,+.

Preferably it is set within the range of 2% to 8%, more preferably 4% to 5%. If it exceeds 10%, the elastic deformation of the protrusion 13 will not be able to absorb the impact of the pulley tooth tips 210, leading to concentration of compressive stress or abnormal meshing between the belt 1 and the pulley 2. If it is less than 1%, the protrusion 13 cannot perform its original function.

Note that the belt dedendum 110 is, as shown in FIG.
Points between AB. Point A is a boundary point between the belt tooth root part 110 and the belt tooth bottom plane part 12, and is the point where the belt starts to incline along the belt tooth 11 toward the belt tooth side part 112 from the belt tooth root plane part 12. Point B is the boundary point between the belt tooth root portion 110 and the belt tooth side portion 112, and the contact point between the belt tooth 11 and the contact M 113 of the belt tooth 11 is the boundary point between the belt tooth root portion 110 and the belt tooth side portion 112.
from an appropriate position on the belt tooth side portion 112 in the direction of the belt tooth l.
When moving on l, this is the point at which the angle α between this tangent line 113 and the belt tooth center line 114 begins to increase. Also, what is the pulley tooth tip portion 210?

As shown in FIG. 10, it refers to the area between A' and B'. Point A' is the boundary point between the pulley tooth tip 210 and the pulley tooth top 211, and is the point of contact between the common tangent line 23 between adjacent pulley teeth 21 and the pulley tooth 21. Point B is at the pulley tooth tip 2
10 and the pulley tooth side part 212, and the pulley @
21 and the tangent vA213 of the pulley tooth 21 moves from an appropriate position on the pulley tooth side 212 on the pulley tooth 21 toward the pulley tooth top 211, the angle formed by this tangent 213 and the pulley groove center line 221 This is the point at which α' starts to increase.

1. The belt 1 is made of a rubber material that is highly flexible and elastic, and has excellent abrasion resistance. It is embedded in the belt 1 due to its excellent flexibility and elasticity.

For example, the impact of the pulley 2 on the core wire 15 made of glass fiber or Kevlar cord is alleviated. Examples of this rubber material include chloroprene rubber, styrene-butadiene rubber, and nitrile-butadiene rubber. The surface of the belt tooth side of the belt 1 is partially coated with nylon fibers, aromatic polyamide fibers, etc.
Reinforcement member 1 made of stretchable canvas, low stretchability or non-stretchability canvas made of polyester fiber, etc., and having excellent abrasion resistance
6 is appropriately coated. This reinforcing member 16 can be appropriately embedded not only in the tooth-side surface of the bell 1-1 but also in the rubber layer. There are no particular restrictions on the shape, pitch, etc. of the belt teeth 11, and they are appropriately set depending on the load applied thereto. When the belt tooth height Hll is set larger than the pulley groove depth Hp, when the belt teeth 11 come into compressive contact with the pulley groove bottom 220, the belt tooth top 111 has a shape that has a sufficient degree of compression deformation freedom. Preferably used.

The pulley 2 may have a shape such that its tooth side portion 212 and tooth top portion 211 are in close contact with the belt tooth side portion 112 and tooth bottom portion 12, respectively, to transmit load (the pulley teeth 21 and the pulley groove 22 are in close contact with the belt tooth side portion 112 and the tooth bottom portion 12, respectively). 14 and the belt teeth 11 do not necessarily have to be similar in shape.

The pulley 2 is usually made of plastic, light alloy, or steel. In this example, a ZB toothed pulley (JASOE
106-81) was used.

The meshing between the toothed Hertoe and the pulley 2 is shown in Figure 3 (a).
1 to 30(d). first.

As the pulley 2 is driven, the protrusion 131 of one belt tooth base 110 comes into compressive contact with the pulley tooth tip 210, and the protrusion 13
1 is elastically deformed on both sides (first stage buffering action; Fig. 3(a)). Next, the belt tooth tip 111 comes into compressive contact with the pulley groove bottom 220, and similarly undergoes elastic deformation on both sides (second stage buffering action; FIG. 3(b)).

Further, at the same time that the belt tooth side portion 112 contacts the pulley tooth side portion 212, the protrusion 1 of the other belt tooth root portion 110
32 comes into compressive contact with the pulley tooth tip 210 and is elastically deformed (third stage buffering action; FIG. 3(C)). Next.

The belt tooth bottom plane portion 12 contacts the pulley tooth top portion 211 (FIG. 3(d)). In this way, the belt tooth bottom plane portion 12
Since the contact between the belt tooth crest 211 and the pulley tooth crest 211 is carried out through the three stages of buffering described above, the impact contact between the belt tooth bottom plane part 12 and the pulley tooth crest 211 is significantly alleviated. As a result, a significant sound reduction effect is brought about. At the same time, belt polygonal behavior can also be relaxed. In addition, the belt tooth height protrusion 1
This impact contact is also alleviated by the elastic deformation of the rubber layer between the belt core wire 15 and the belt core wire 15, so that the above sound reduction effect and the effect of moderating the belt polygonal behavior are further enhanced.

Both root portions 110 of the belt tooth 11 and the belt tooth tip portion 11
1 are in contact with pulley 2 in a compressed state, respectively,
Substantial load transmission of the boot I72 is performed by the meshing between the belt tooth side portion 112 and the pulley tooth side portion 212 and the frictional force between the belt tooth bottom portion 12 and the pulley tooth top portion 211. In addition, substantial stress in the pulley radial direction due to belt tension is supported between the belt tooth bottom portion 12 and the pulley tooth top portion 211. Therefore, both root parts 1 of the belt teeth 11
10 and the belt tooth tips 111 are not subject to stress concentration. Moreover.

Each of these parts has a space that absorbs the elastic deformation of the rubber due to compression, so that excessive wear does not occur at the protrusion and the top.

Therefore, it is possible to maintain the above sound reduction effect for a long period of time.

Furthermore, according to the device of the present invention, since the belt dedendum portion 110 tends to be compressed, tensile stress during load transmission is not concentrated in this portion. Furthermore, since the canvas coated on the surface of the belt dedendum 110 has a degree of freedom in the tensile direction, it can absorb the influence of the transmitted load applied to the belt tooth side 112, and prevent the occurrence of canvas cracking at the belt dedendum 110. The time can be extended. Also in the belt tooth bottom portion 12, the shock surface pressure of the pulley tooth top portion 211 is avoided by the buffering effect of the root portion protrusion 13, and at the same time, this protrusion 13
This shows the effect of increasing the bending radius when bending.

Therefore, bending fatigue at the belt tooth bottom portion 12 is alleviated, and it becomes possible to extend the time until canvas cracking occurs at this portion. As a result, the durability of the belt is significantly improved.

Other embodiments of the device of the present invention will be described below.

Among the buffering effects of the protrusions 13 provided on the dedendum portion 110 of each belt tooth 11, the buffering effect of the protrusions I3, which occurs immediately before the belt tooth bottom plane portion 12 contacts the pulley tooth top portion 211, is particularly reduced. It greatly contributes to the sound effect °. Therefore, as shown in FIG. 4, the protrusion 13 can be provided only on the side of each belt dedendum 110 that will later come into contact with the pulley tooth tip 210. The other root portion 110 may have a conventional shape. Moreover, the cross-sectional shape of the protrusion 13 is as follows.

As shown in FIG. 5(a), it is also possible to form a planar shape that can maintain an appropriate compression margin with the pulley tooth tip 210. As shown in FIG. 5 (bl), a plurality of protrusions 13 may be provided.Furthermore, protrusions 13 of different shapes may be provided at each belt dedendum.

In the apparatus of the present invention, as shown in FIG.

It is also possible for the height H8 of the belt teeth 11 to be smaller than or equal to the depth H7 of the pulley groove 22.

In this case, compared to the above embodiment, the belt tooth tip 11
Since there is no buffering effect at 1, the sound reduction effect will be less, but
Due to the presence of the protrusion 13, a remarkable sound reduction effect is exhibited even compared to the conventional device.

In addition, in the device of the present invention, not only the protrusion 13 is provided on the belt dedendum 110, but also an appropriate compression clearance is provided on at least one of the pulley dedendums 213, as shown in FIG. A protrusion 24 can be provided that can be brought into compressive contact with each other. In this case, the damping effect when the belt 1 and pulley U2 engage is performed in at least four stages, so that the sound reduction effect can be further enhanced. Figure 8 (al
and FIG. 8 (bl) shows an example in which the shape of the pulley tooth tip 210 is made concave or planar, respectively, in order to appropriately adjust the deformation area (compression allowance) that occurs in the belt dedendum protrusion 13. .

In addition to the above embodiments, protrusions are provided on the tips of the belt teeth, the bottom of the pulley teeth on the sides of the belt teeth, or the sides of the pulley teeth, and by combining these, the number of times the buffering action is increased and the sound reduction effect is further enhanced. It is also possible to increase it.

(Effect of the invention) The toothed belt transmission device of the present invention is thus constructed.

The shock-absorbing effect of the protrusion provided at the root of the belt can alleviate the impactful contact between the flat surface of the bottom of the belt tooth and the top of the tooth of the pulley. As a result, the impact noise generated when the belt and pulley engage can be significantly reduced. Moreover, the sound reduction effect can be maintained for a long period of time. Furthermore, this buffering action relieves stress concentration at the belt tooth bottom plane portion and belt tooth root portion, and prevents cracking of the belt canvas. As a result, the durability of the belt can be significantly improved.

4. Figures 1 and 2 are front views of essential parts showing one embodiment of the toothed belt and pulley of the device of the present invention, and Figure 3 (
a) to FIG. 3(d) are front cross-sectional views of main parts, FIG. 4, and FIG. 5 (al) and FIG. ),
6, 7, 8 (a) and 8 (bl is a front sectional view of the main part showing another embodiment of the device of the present invention, respectively;
FIG. 9 is a front view of a main part illustrating the dedendum of a toothed belt in an embodiment of the apparatus of the present invention, FIG. 10 is a front view of a main part illustrating a tooth tip of a pulley, FIG. 12 and FIG. 13 are a front view and a front sectional view of a main part of a conventional toothed belt transmission, respectively.

1, 300.500.700...Toothed belt, 2
．． 400.600°800...Pulley, 11.30
2...belt teeth, 12.・・・Belt tooth bottom plane part,
13.131.132...Protrusion, 110.304.
...Belt tooth base, 210...Pulley tooth tip.

9i Figure 4 First 6 figures First 7 figures

Claims (1)

[Claims] 1. A toothed belt transmission device comprising a toothed belt having teeth at a constant pitch in the longitudinal direction of the belt, and at least two pulleys meshing with the toothed belt, wherein the belt is connected to the pulleys. A toothed belt transmission device configured such that at least a portion of at least one of the dedendum portions of each belt tooth comes into compressive contact with the tooth tip portion of the pulley with an appropriate compression margin when meshing. 2. A patent claim in which, when the belt and the pulley mesh in a stationary state, the maximum compression distance between the belt tooth base and the pulley tooth tip is within 1% to 10% of the belt tooth height. The toothed belt transmission device according to item 1. 3. The toothed belt transmission device according to claim 1, wherein compressive contact with the tooth tips of the pulley is made by at least one protrusion provided on the tooth base of the belt. 4. The toothed belt transmission device according to claim 3, wherein the protrusion is provided in at least a part of the tooth root portion of the belt in a tooth width direction perpendicular to the belt longitudinal direction. 5. When the protrusion comes into compressive contact with the pulley tooth tip,
The toothed belt transmission device according to claim 3, which has a shape that can be elastically deformed while maintaining a sufficient degree of freedom.