JP2001140922A - Chain coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chain coupling capable of dispensing with application of lubricant and a cover and being used continuously in a clean environment. SOLUTION: This chain coupling 10 consists of metallic sprockets 12, 14 fixed on a drive shaft A and a driven shaft B, respectively, and a chain 16 wound around these sprockets 12, 14. A roller 30 is rotatably attached to an outer side of a bush 26 of the chain 16. The roller 30 is formed by self- lubricating resin capable of being elastically deformed easily when compared with steel. The roller 30 is made of, for example, polytetrafluoroethylene. The roller 30 is formed to have a radius R2 slightly larger than a radius R1 of a tooth bottom face 18 of sprockets 12, 14. The roller 30 adheres closely on the tooth bottom face 18 and is elastically deformed when the chain 16 is applied to respective sprockets 12, 14 by forming R1<=R2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chain coupling in which a pair of sprockets arranged substantially coaxially is connected by a chain.

[0002]

2. Description of the Related Art In a chain coupling, a chain having a rotatable roller is wound around a bush between a pair of sprockets, and the roller is meshed with the tooth bottom surface of the sprocket to transmit torque between the pair of sprockets. It is a mechanical part. The sprockets are fixed to a drive shaft and a driven shaft which are substantially coaxially and axially separated, and two rows of chains are wound around the respective sprockets in phase. In general, an inner plate in which a bush is press-fitted at both ends and an outer plate in which a pin penetrating through the bush is press-fitted to the chain are alternately connected, and a roller is provided on the bush. When a chain is wound around a pair of sprockets so that the rollers mesh with the tooth bottom surfaces of the sprockets and the chain is connected endlessly, a chain coupling that transmits torque between the pair of sprockets is assembled.

[0003]

However, in the conventional chain coupling, both the sprocket and the chain are made of steel, and the radius of the roller is formed to be slightly smaller than the radius of the sprocket tooth bottom surface. Considering the behavior of rollers and sprockets in such a chain coupling, the center of curvature of the roller outer peripheral surface and the center of curvature of the sprocket tooth bottom surface change due to changes in transmission torque and changes in angular velocity and angular acceleration during start / stop. The roller is relatively displaced in the circumferential direction, and the roller rolls or slides on the tooth bottom surface. Therefore, a lubricant is required between the bush and the roller and between the roller and the tooth bottom surface in order to prevent wear of the sliding portion and generation of wear powder.

[0004] Therefore, a large amount of grease or the like is used between these members. Chain coupling is 100
Since it is often used at a rotation speed of about rpm to 1000 rpm, there is a problem that grease scatters around. In order to prevent this, it is necessary to provide a cover that covers the sprocket in the chain coupling,
Even if the cover is provided, it is difficult to completely prevent the grease from scattering because the fluid grease leaks from the cover during rotation. Further, when a cover for covering the sprocket is provided, the moment of inertia of the chain coupling itself becomes large, the torque cross becomes large, and there is a problem that the torque transmission efficiency decreases. Further, even if a cover is provided, the machine must be stopped at regular intervals, the cover must be removed, and maintenance and inspection and replacement of grease must be performed.

An object of the present invention is to provide a chain coupling that can be used continuously without the need for applying a lubricant or the like, does not require a cover, and can be used in a clean environment. is there.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a chain having rollers rotatable on a bush is wound between a pair of sprockets arranged substantially coaxially, and the sprocket is mounted on a tooth bottom surface of the sprocket. In a chain coupling in which rollers are engaged to transmit torque between a pair of sprockets, a tooth bottom surface of the sprocket is formed in an arc shape, and an outer peripheral surface of a roller of the chain is formed in a cylindrical shape. The problem is solved by a chain coupling in which the roller is molded from a lubricating resin and the radius of the roller is equal to or larger than the radius of the tooth bottom, and the cylindrical outer peripheral surface of the roller is brought into close contact with the tooth bottom. Settled.

When the chain is wound around the pair of sprockets in phase, if the radius of the roller is the same as the radius of the tooth bottom, the outer peripheral surface of the roller comes into close contact with the tooth bottom. Also,
When the radius of the roller is slightly larger than the radius of the tooth bottom, the outer peripheral surface of the roller deforms and comes into close contact with the tooth bottom. in this case,
It is preferable that the roller is deformed in the elastic range and the outer peripheral surface thereof is brought into close contact with the tooth bottom surface of the sprocket.

In the present invention, the roller is formed from a self-lubricating resin. By molding from resin, elastic deformation is easy, and even if the radius of the roller is slightly larger than the radius of the tooth bottom, the roller is in close contact with the tooth bottom. Also,
By molding the roller from self-lubricating resin, it is not necessary to lubricate the parts where sliding occurs, that is, between the bush and the roller, or between the roller and the tooth bottom,
The chain coupling can be used continuously without lubrication.

[0009] Roller materials for continuous use of the chain coupling include sulfides such as molybdenum disulfide, and the like.
A resin containing a solid lubricant such as an oxide, a nitride, or graphite is preferable, and polytetrafluoroethylene or polyacetal is particularly preferable. Since polytetrafluoroethylene or polyacetal is easily deformed elastically, it is easy to make close contact with the tooth bottom surface of the sprocket, and has self-lubricating properties. Therefore, there is an effect of reducing abrasion of the bush or the sprocket during sliding.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a chain coupling according to the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a chain coupling, FIG. 2 is a plan view of a chain used in the chain coupling, and FIG. 3 is a cross-sectional view showing a relationship between a tooth bottom surface of a sprocket and a chain roller. The chain coupling 10 includes, for example, a drive shaft A and a driven shaft B
This is a mechanical instrument used to connect on the same axis. Metal sprockets 12 and 14 are fixed to the drive shaft A and the driven shaft B, respectively. A chain 16 is wound around these sprockets 12 and 14. The chain 16 transmits torque between the drive shaft A and the driven shaft B.

Each of the sprockets 12 and 14 is a sprocket having an arcuate tooth bottom surface 18 such as an S-tooth shape, a U-tooth shape, and an ISO tooth shape according to JIS B 1801-1997. The chain 16 that can be used in the chain coupling of the present invention, as shown in detail in FIGS.
4 and a pair of outer plates 20 and 20, and a central outer plate 2
2, 22; a pin 24 attached to these outer plates; and inner plates 28, 28, 28, 28 in which bushings 26, 26 for inserting the pins 24 are inserted. A roller 30 is rotatably mounted outside each bush 26. Each part of the chain 16
Except for the roller 30, it may be made of steel.

The chain 16 is connected to each sprocket 1
The roller 30 meshes with the tooth bottom 18 of the sprockets 12 and 14 by being wound around the sprockets 2 and 14. The roller 30 in the present invention is formed from a self-lubricating resin that is easily elastically deformed compared to steel. The roller 30 is made of, for example, polytetrafluoroethylene. The roller 30 is formed with a radius R2 slightly larger than the radius R1 of the tooth bottom 18 of the sprockets 12 and 14.
Note that the radius R2 of the outer peripheral surface of the roller 30 may be substantially the same as the radius R1 of the tooth bottom 18.

After matching the phases of the sprockets 12 and 14 on the drive shaft A and the driven shaft B, the chain coupling 10 is designed so that the rollers 30 of the chain 16 mesh with the tooth bottoms 18 of the respective sprockets 12 and 14. It is assembled by winding and tensioning the chain 16 and finally attaching the pins 24, as shown in FIG. At this time, the outer diameter or radius of the roller 30 is determined to such an extent that the roller 30 is deformed in the elastic range. Thus, R1 ≦
By setting R2, when the chain 16 is attached to the respective sprockets 12, 14, the rollers 30
Is in a state of being elastically deformed in close contact with the tooth bottom surface 18. In the present invention, in the use of a chain coupling, attention is paid to the fact that there is almost no sliding between the bush and the roller, and the roller molded from a self-lubricating resin is elastically deformed and brought into close contact with the tooth bottom surface. If so, there is almost no sliding between the roller and the tooth bottom surface, and the roller does not roll with respect to the tooth bottom surface, so that lubrication between the bush and the roller is unnecessary. Further, by deforming the roller in the elastic region and bringing the roller into close contact with the tooth bottom surface, an effect of preventing vibration and noise is also exerted.

Next, a comparative test was conducted between the conventional product and the product of the present invention. The chain coupling used in the comparative test uses a chain coupling composed of 12 links in a two-row chain of JIS # 40 as a conventional product. A chain coupling made of fluoroethylene was used.
As shown in FIG. 4, an apparatus for generating electric power by receiving the rotational torque of the driving motor by the driven motor via the chain coupling 10 as shown in FIG. 4 was used. Both the conventional product and the product of the present invention were sufficiently degreased with an organic solvent, and the chain coupling was subjected to a test without lubrication. The number of rotations of the chain coupling is 1230 rpm and the transmission capacity is 9.9k
At W, a test was conducted for 350 hours. Before and after the test,
The state of the chain coupling between the conventional product and the product of the present invention was examined.

FIG. 5 shows the results of the comparative test. In the conventional product, wear progressed between the bush and the roller, and between the roller and the tooth bottom surface of the sprocket, and red-brown abrasion powder was generated. The roller was found to lose 70 μg in weight due to wear. A sliding mark parallel to the sliding direction (circumferential direction) of the bush due to sliding with the roller was observed. The average depth of the sliding marks was 7 μm and the maximum was 12 μm. When the test was continued as it was, it was recognized that the generation of abrasion powder, the decrease in mass, and the sliding trace further progressed. On the other hand, in the present invention product, generation of wear powder was not recognized. For this reason, there was almost no decrease in mass. The bush had almost no sliding traces with the roller, and no distinction between surface roughness and sliding traces was recognized. Further, when the sliding surface of the bush was analyzed with an electron beam microanalyzer for the product of the present invention, it was confirmed that fluorine in polytetrafluoroethylene was uniformly distributed on the bush surface. As a result, it is recognized that the fluorine uniformly adhered to the sliding-side mating surface, and a fluorine-adhered layer was formed on the sliding-side bushing surface, thereby reducing wear.

The radius of the roller of the present invention in the above comparative test is slightly smaller than the radius of the sprocket tooth root, but the roller radius R1 is slightly larger than the radius of the sprocket tooth root. By deforming the roller in close contact with the bottom surface of the sprocket in the elastic range, it is expected that the sliding of the roller and the bush, and the rolling and sliding of the bottom surface of the roller are almost eliminated. Therefore, even a little abrasion occurs, by bringing the roller into close contact with the tooth bottom,
It is possible to further reduce it, and by doing so, it is expected that the period of continuous use will be prolonged.

[0017]

According to the present invention, as described in detail above, since the roller is formed from a self-lubricating resin, a lubricant such as grease, which was required in the past, is not required, and the grease is replaced at regular intervals. In addition, maintenance and inspection for advancing wear become unnecessary, and the chain coupling can be used continuously. And since no lubricant is needed,
Suitable for use in a clean environment. Further, since a lubricant is not required, it can be used without separately providing a component such as a cover. Therefore, in addition to being able to reduce the number of parts, the moment of inertia is reduced, and the torque transmission efficiency can be improved. In addition, since the outermost roller of the chain is made of resin, the moment of inertia is smaller than that of steel rollers, and the use of such a lightweight material also improves torque transmission efficiency. Can be.

In the present invention, since the resin roller is deformed in the elastic range and is brought into close contact with the tooth bottom surface of the sprocket, a change in transmission torque and a change in angular velocity and angular acceleration at the time of starting / stopping can be achieved. Rolling and sliding hardly occur between the roller and the tooth bottom surface. Such behavior can reduce vibration and wear, absorb misalignment between shafts and sprockets, and reduce noise. It has a remarkable effect.

[Brief description of the drawings]

FIG. 1 is a perspective view of a chain coupling according to the present invention.

FIG. 2 is a plan view of a chain used for a chain coupling.

FIG. 3 is a sectional view showing a relationship between a tooth bottom surface of a sprocket and a roller of a chain.

FIG. 4 is a block diagram of a comparative test apparatus.

FIG. 5 is a graph of a comparison test result.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Chain coupling 12, 14 Sprocket 16 Chain 18 Bottom surface 20, 22 Outer plate 24 Pin 26 Bush 28 Inner plate 30 Roller

Claims (1)

[Claims] 1. A chain provided with a roller rotatable on a bush is wound between a pair of sprockets disposed substantially coaxially, and the roller is meshed with a tooth bottom surface of the sprocket to form a pair of sprockets. In a chain coupling for transmitting torque between sprockets, the tooth bottom surface of the sprocket is formed in an arc shape, the outer peripheral surface of a roller of the chain is formed in a cylindrical shape, and the roller is formed from a self-lubricating resin. A chain coupling, wherein a radius of a roller is formed to be equal to or larger than a radius of the tooth bottom surface, and a cylindrical outer peripheral surface of the roller is brought into close contact with the tooth bottom surface.