JP2004044659A - Sprocket and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sprocket capable of inhibiting generation of noise in engagement with roller chain, easy to manufacture, and capable of retaining silencing effectiveness over long period of time, and a method for manufacturing the same. <P>SOLUTION: This sprocket 1 has a plurality of teeth 5 engaging with roller chain 20 formed on an outer circumference part of a sprocket main body 2. A first elastic body 11 getting into contact with link plates 21a, 22a of the roller chain 20 when the sprocket 1 engages with the roller chain 20 is provided in both end surfaces of the sprocket main body 2, a second elastic body 12 getting contact with rollers of the roller chain 20 is provided at a root part of the sprocket main body 2, and the first elastic body 11 and the second elastic body 12 are formed as one body. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sprocket that transmits power by meshing with a roller chain and a method for manufacturing the same.
[0002]
[Prior art]
In a power transmission mechanism using a roller chain and a sprocket, when the roller chain meshes with the sprocket, noise occurs due to the rollers of the roller chain colliding with the tooth bottoms of the sprocket.
As a sprocket for suppressing the generation of such noise, the present inventors have developed a sprocket in which a groove is formed in a tooth bottom and an elastic body is stored in a protruding state in the groove, and this sprocket is disclosed in This is disclosed in JP-A-2001-27307. According to this sprocket, when the roller chain meshes, the collision energy of the roller is reduced by the elastic body at the tooth bottom, so that the noise generated by the roller colliding with the tooth bottom can be largely suppressed. The effect is obtained.
[0003]
[Problems to be solved by the invention]
However, in the sprocket, it is necessary to prevent the elastic body from coming off due to centrifugal force, for example, by forming a protrusion between the groove and the tooth bottom, and as a result, the shape of the sprocket body is complicated. As a result, there is a problem that processing of the sprocket body is difficult. In addition, it is necessary to attach an elastic body to each of the plurality of grooves, and there is a problem that the attaching work is troublesome.
[0004]
Further, as another conventional sprocket that suppresses the generation of the above noise, annular elastic bodies are attached to both end faces of the sprocket body, and when the roller chain meshes, the elastic body receives the link plate of the roller chain and receives the roller. There are known sprockets designed to mitigate collisions.
However, in the sprocket described above, although the collision of the rollers is moderated and the generation of noise is suppressed to some extent, the contact of the link plate is concentrated on a part of the elastic body, so the elastic body is heavily worn, and the sprocket is short-lived. There was a problem that the noise reduction effect was attenuated in between.
[0005]
The present invention has been made in view of such circumstances, and it is possible to suppress generation of noise when meshing with a roller chain, and it is easy to manufacture, and a sprocket that can maintain a noise reduction effect for a long time and a sprocket thereof. It is intended to provide a manufacturing method.
[0006]
[Means for Solving the Problems]
According to the first aspect of the present invention, in a sprocket in which a plurality of teeth meshing with a roller chain are formed on an outer peripheral portion of a sprocket body, a first elastic body with which a link plate of the roller chain abuts when the roller chain meshes. Are provided on both end surfaces of the sprocket main body, while a second elastic body with which the roller of the roller chain is in contact is provided at a tooth bottom of the sprocket main body, and the first and second elastic bodies are integrally formed. Things.
[0007]
According to the sprocket according to the first aspect of the present invention, the first elastic body provided on both end faces of the sprocket main body and the second elastic body provided on the tooth bottom of the sprocket main body are integrally formed to form the first sprocket. Since the elastic body and the second elastic body are connected to each other, it is not necessary to form a projection or the like on the sprocket body to prevent the second elastic body from coming off due to centrifugal force or the like. It will be easier.
Further, when the roller chain meshes, the link plate of the roller chain abuts on the first elastic body, and the roller of the roller chain abuts on the second elastic body. The collision can be reduced, and the noise generated when the roller collides with the tooth bottom can be greatly suppressed.
Further, since the contact of each part of the roller chain with the elastic body is dispersed, the wear of the elastic body can be prevented, and the silencing effect can be maintained for a long period of time.
[0008]
According to a second aspect of the present invention, in the first aspect of the present invention, the sprocket main body is provided with a through hole penetrating in an axial direction thereof, and the through hole is disposed on both end surfaces of the sprocket main body. A connecting portion is provided for connecting the first elastic members to each other, and the connecting portion is integrally formed with the first and second elastic members.
[0009]
According to the second aspect of the present invention, the first elastic members disposed on both end surfaces of the sprocket main body are connected to each other by the connecting portion provided in the through hole of the sprocket main body. (2) The elastic body and the sprocket main body can be firmly integrated, and the elastic body can be prevented from falling off.
[0010]
According to a third aspect of the present invention, there is provided the method of manufacturing a sprocket according to the first or second aspect, wherein the sprocket body is inserted into a mold before the first and second elastic members are formed, and the insert molding is performed. By performing the above, the first and second elastic bodies or the first and second elastic bodies and the connecting portion are integrated with the sprocket body.
[0011]
According to the third aspect of the present invention, it is easy to integrate the first and second elastic bodies and the sprocket body, and it is easy to manufacture the sprocket.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
1 to 4 show an embodiment of a sprocket according to the present invention, and reference numeral 1 in the figure denotes a sprocket.
The sprocket 1 is configured by assembling an elastic body 10 that suppresses noise generation to a sprocket body 2 having a plurality of (15 in the illustrated example) teeth 5 meshing with a roller chain 20 formed on an outer peripheral portion.
[0013]
The sprocket body 2 is a disk-shaped member made of steel or the like, and has a shaft hole 3 at the center thereof, and a drive shaft or a driven shaft is inserted into the shaft hole 3 to be integrally rotated. It has become. As shown in FIG. 1, the sprocket body 2 is provided with a plurality of (six in the illustrated example) through holes 4 penetrating in the axial direction on the same circumference.
In the present embodiment, the teeth 5 of the sprocket body 2 are formed in a U-tooth shape, and a groove 6 having a substantially U-shaped cross section is formed in the tooth bottom in the axial direction of the sprocket body 2. The groove 6 is formed so as to open to the tooth bottom side and both end faces of the sprocket body 2. Further, as shown in FIG. 3, the groove 6 is formed so that the width in the circumferential direction in the groove is substantially constant, and the bottom and the edge are chamfered, respectively. For this reason, when the roller chain 20 meshes with the sprocket 1, the contact range between the roller 23 and the elastic body 10 is widened, and the amount of deformation at the contact portion is also large.
[0014]
As shown in FIGS. 1 and 2, the elastic body 10 has a substantially annular first elastic body 11 disposed on each of both end surfaces of the sprocket main body 2, and a plurality of elastic bodies 10 fitted into the through holes 4 of the sprocket main body 2. And the plurality of second elastic bodies 12 fitted in the respective grooves 6 of the sprocket body 2 are integrally formed, and are formed of a cushioning material such as urethane or nitrile rubber.
[0015]
As shown in FIGS. 1 and 3, the first elastic body 11 is formed in such a size that the link plates 21 a and 22 a of the roller chain 20 can contact the outer peripheral portion when the roller chain 20 meshes. Furthermore, the first elastic body 11 is formed to have a size that covers about half of the opening of each groove 6 and the entirety of each through hole 4 from the axial direction of the sprocket body 2, and the inner peripheral side thereof has a plurality of connecting portions. 13, and the outer peripheral side is connected by a plurality of second elastic bodies 12.
On the other hand, the second elastic body 12 is formed in a column shape having an outer surface that is shaped along the inner surface of the groove 6, and is housed in the groove 6 with one side exposed to the tooth bottom. A plurality of the second elastic bodies 12 are provided along the circumferential direction of the sprocket 1, and a portion of each sprocket 1 near the center in the radial direction is connected to both the first elastic bodies 11.
[0016]
Further, the first elastic body 11 is provided with a plate contact surface 11a with which the link plates 21a and 22a come into contact when the roller chain 20 meshes, while the second elastic body 12 is formed with the roller chain 20 meshing. Is provided with a roller contact surface 12a with which the roller 23 contacts, and the contact surfaces 11a and 12a are arranged in a state of being offset in the radial direction of the sprocket 1. That is, the elastic body 10 is configured to receive loads from both the link plates 21a and 22a of the roller chain 20 and the roller 23 when the roller chain 20 meshes.
[0017]
The roller chain 20 is composed of a number of inner links 21 and outer links 22, as shown in FIG. Each inner link 21 is formed by press-fitting and integrating two bushes between a pair of link plates 21a, and a roller 23 is rotatably provided on the outer periphery of the bush. The outer link 22 is formed by press-fitting and integrating two pins 22b between a similar pair of link plates 22a. In the roller chain 20, the inner links 21 and the outer links 22 are alternately arranged, and the pins 22b of the outer links 22 are inserted into the bushes of the adjacent inner links 21 and connected to each other, so that the endless links are endless. It is formed in a shape.
[0018]
When the roller chain 20 meshes with the sprocket 1, the link plates 21a and 22a abut on the first elastic body 11, so that the roller 23 abuts on the second elastic body 12 and the collision of the roller 23 is reduced. It has become so.
When the roller chain 20 meshes with the sprocket 1, the first elastic body 11 and the second elastic body 12 are compressed in the radial direction of the sprocket 1 as shown in FIG. Is a compressed portion.) Therefore, energy due to the load from the roller chain 20 is absorbed as deformation and heat of the elastic body 10, and as a result, a noise reduction effect is generated.
At this time, the load from the roller chain 20 causes deformation of the elastic body 10 in the rotation axis direction of the sprocket 1. In the sprocket 1 according to the present invention, the first elastic body 11 and the second elastic body By releasing the load received by the second elastic body 12 to the first elastic body 11 through the connection portion with the body 12, the second elastic body 12 supports the first elastic body 11 at the connection portion, The first elastic body 11 effectively absorbs the load in the radial direction of the sprocket 1 while preventing the so-called peeling direction (the rotation axis direction of the sprocket 1) from being deformed by the load applied to the first elastic body 11. .
Further, a pair of first elastic bodies 11 arranged on both surfaces of the sprocket main body 2 are connected by connecting portions 13 at a plurality of positions near a radial center of the sprocket 1 and along a circumferential direction of the sprocket 1. Since this structure has an effect of effectively dispersing the radial load of the sprocket 1 received by the first elastic body 11, an excellent noise reduction effect is produced against the load received by the elastic body 10 as a whole.
[0019]
When manufacturing the sprocket 1 having the above configuration, first, the sprocket body 2 is manufactured through processing steps such as cutting and surface treatment. Next, the elastic body 10 is molded by a molding method such as injection molding or casting using the produced sprocket body 2 as an insert part. That is, the sprocket body 2 is set at a predetermined position in the mold for molding the elastic body 10, and in this state, the molding material of the elastic body 10 such as urethane is filled in the cavity of the mold and the molding material is cured. Then, insert molding is performed. Thereby, the sprocket main body 2 is integrated with the elastic body 10 having the first elastic body 11, the second elastic body 12, and the connecting portion 13 and the sprocket 1 is manufactured.
[0020]
As described above, according to the sprocket 1, the first elastic members 11 provided on both end surfaces of the sprocket body 2 and the second elastic members 12 provided on the tooth bottoms of the sprocket body 2 are integrally formed. Since the first elastic body 11 and each of the second elastic bodies 12 are connected to each other, it is not necessary to form a projection or the like on the sprocket body 2 for preventing the second elastic body 12 from coming off due to centrifugal force or the like. Therefore, processing of the sprocket main body 2 becomes easy.
Further, since the contact of each part of the roller chain 20 with the elastic body 10 is dispersed, the wear of the elastic body 10 can be prevented, and the noise reduction effect can be maintained for a long period of time.
Further, the inner peripheral side of the first elastic body 11 is connected by the plurality of connecting portions 13 and the outer peripheral side of the first elastic body 11 is connected by the plurality of second elastic bodies 12. The sprocket main body 2 and the sprocket main body 2 can be firmly integrated, and the elastic body 10 can be prevented from falling off.
[0021]
Further, when the roller chain 20 is engaged, the link plates 21a and 22a of the roller chain 20 abut on the first elastic body 11 and the rollers 23 of the roller chain 20 abut on the second elastic body 12, so that the first elastic The cooperation of the body 11 and the second elastic body 12 can reduce the collision of the roller 23, and can significantly suppress the noise generated when the roller 23 collides with the tooth bottom.
As a result of comparison with a conventional sprocket in which only annular elastic bodies are attached to both end surfaces of the sprocket body, as shown in FIG. It was confirmed that a better noise suppression effect than a sprocket could be obtained.
[0022]
【The invention's effect】
As described above, according to the sprocket according to the present invention, there is no need to form a projection or the like on the sprocket body to prevent the second elastic body from coming off due to centrifugal force or the like. .
Further, since the collision of the rollers is reduced by the cooperation of the first and second elastic bodies, it is possible to significantly suppress the noise generated when the rollers collide with the tooth bottom.
In addition, since the contact of each part of the roller chain with the elastic body is dispersed, it is possible to prevent the elastic body from being worn, and to maintain the silencing effect for a long period of time.
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment of a sprocket according to the present invention.
FIG. 2 is a sectional view taken along the line AA of FIG. 1;
FIG. 3 is an enlarged view showing a periphery of a groove portion of the sprocket of FIG. 1;
4A and 4B are graphs comparing the noise reduction effect of a sprocket according to the present invention and a conventional sprocket, wherein FIG. 4A shows a case where the number of teeth is 15 and FIG. 4B shows a case where the number of teeth is 18; .
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sprocket 2 Sprocket main body 4 Through hole 5 Teeth 6 Groove 11 First elastic body 12 Second elastic body 13 Connecting part 20 Roller chains 21a, 22a Link plate 23 Roller

Claims (3)

In a sprocket in which a plurality of teeth meshing with a roller chain are formed on an outer peripheral portion of a sprocket body,
A first elastic body with which the link plate of the roller chain abuts when the roller chain meshes is provided on both end surfaces of the sprocket body, and a second elastic body with which the roller of the roller chain abuts is provided at the bottom of the sprocket body. A sprocket, wherein the first and second elastic bodies are integrally formed. The sprocket main body is provided with a through-hole penetrating in the axial direction thereof, and the through-hole is provided with a connecting portion for connecting the first elastic bodies disposed on both end surfaces of the sprocket main body to each other, The sprocket according to claim 1, wherein the connecting portion is formed integrally with the first and second elastic bodies. It is a manufacturing method of the sprocket according to claim 1 or 2,
By inserting the sprocket body into a mold and performing insert molding before molding the first and second elastic bodies, the first and second elastic bodies or the first and second elastic bodies and the A method of manufacturing a sprocket, wherein a connecting portion and the sprocket body are integrated.

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