JP2009138800A - Chain - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chain capable of restraining a meshing sound, by reducing impact in meshing, while maintaining required rigidity. <P>SOLUTION: A timing chain 30 has a pair of outer ring plates 41 and a pair of inner ring plates 42, and these plates are alternately connected in the traveling direction. A pair of bushings 44 are arranged on the respective inner ring plates 42 by fixing both end parts. A pair of pins 43 are arranged on the respective outer ring plates 41 by fixing both end parts. These pins 43 are respectively inserted into a pin hole 44a of the bushings 44. The respective bushings 44 have a thinner shape in its thickness than a part positioned outside these pins 43 in a part positioned between the pair of pins 43. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a chain formed by alternately connecting an inner plate and an outer plate.

  For example, as described in Patent Document 1, as a commonly used chain structure, the chain has a pair of outer link plates into which pins are press-fitted and a pair of inner link plates into which bushes are press-fitted. It is known that the inner link plate and the outer link plate are alternately connected by inserting pins of the outer link plate into the bush of the plate.

Such a chain is widely used as a timing chain for opening and closing an intake valve and an exhaust valve of an internal combustion engine, for example. In other words, the timing chain is engaged with the crank sprocket provided on the crankshaft and the cam sprocket provided on the camshaft, and the timing chain travels as the cranksprocket rotates. Is transmitted to the camshaft, and the intake valve and the exhaust valve are driven to open and close.
Japanese Utility Model Publication No. 7-22158

  By the way, in such a chain, when the chain meshes with the sprocket during high-speed rotation of the sprocket, an impact force based on the inertia of the chain acts on the sprocket from the chain. Noise may occur. In particular, in the case where the quietness is required like an in-vehicle internal combustion engine, it is desirable to reduce the noise generated by such chain driving as much as possible. Here, for example, in order to suppress such noise, it is conceivable to reduce the weight of the chain member. However, if the entire chain is simply reduced in weight, it may not be possible to secure the required rigidity for each member of the chain, which may reduce the useful life of the chain or limit the drive force that can be transmitted. Inconvenience such as being caused will occur.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a chain capable of reducing meshing noise by reducing impact during meshing while maintaining necessary rigidity. .

In the following, means for achieving the above object and its effects are described.
The invention according to claim 1 includes a pair of inner plates, and a pair of inner plates having pin holes that are fixed to both ends of the pair of inner plates and penetrate from one side of the pair of inner plates to the other. A pair of bushes provided at each end of the plate, a pair of outer plates provided outside the inner plate so that the ends of the pair of inner plates overlap with each other, and inserted into the pin holes of the bush The pair of bushes provided on the pair of inner plates in a chain comprising a pair of pins fixed at both ends to the pair of outer plates and the inner plate and the outer plate being alternately connected to each other Is a portion where the portion located between the pair of pins in the longitudinal direction of the inner plate is located outside the pins. Also as its gist that the thickness thereof becomes a thinner shape than.

  When the chain travels, each pin that passes through the pin hole of the bush is pulled toward the opposite side in the longitudinal direction of the inner plate by each outer plate to which both ends thereof are fixed. Therefore, the load acting on the portion located between the pair of pins in the longitudinal direction of the inner plate is smaller than the load acting on the portion located outside each pin. In this respect, according to the above configuration, the thickness on the side where the load acting on the bush is large is kept as it is, and only the thickness on the side where the load is small is thinned, thereby maintaining the rigidity required for the load acting on the bush. However, it is possible to reduce the weight of the bush, in other words, to reduce the weight of the entire chain. Therefore, the meshing noise can be suppressed by reducing the impact at the time of meshing while maintaining the rigidity of the chain.

  According to a second aspect of the present invention, in the chain according to the first aspect, the pair of bushes has a circular cross section, and the pin holes are closer to each other than the centers of the bushes in the longitudinal direction of the pair of inner plates. The gist is to be formed at a position eccentric to the side to be.

  According to the above configuration, in the bush having a circular cross section, the center position of the pin hole is decentered to the side where the load acting on the bush from the pin is small in the longitudinal direction of the inner plate, thereby adding to the bush in the running direction of the chain. While maintaining the wall thickness on the large load side, the wall thickness on the small load side can be reduced, so that the weight of the entire chain can be reduced while maintaining rigidity according to the load applied to the bush. Become.

The gist of the invention described in claim 3 is that, in the chain described in claim 2, a roller is rotatably fitted around the pair of bushes.
According to the above configuration, even in the case of a roller chain in which a roller is externally fitted to the bush, similarly, it is possible to reduce the weight of the entire chain while maintaining rigidity according to a load acting on the bush. .

  According to the first to third aspects of the present invention, in order to transmit the rotational force of the crank sprocket provided on the crankshaft of the in-vehicle internal combustion engine to the cam sprocket provided on the camshaft. This can be embodied as a timing chain.

  In general, in an in-vehicle internal combustion engine, the crankshaft rotates at a relatively high speed, so that the occurrence of noise due to the inertia of the chain as described above becomes significant. In addition, quietness is strongly desired for in-vehicle internal combustion engines. In this regard, as in the invention described in claim 4, by applying the invention described in claims 1 to 3 to the timing chain of such an internal combustion engine, it is possible to suppress the generation of noise accompanying the traveling of the chain. It is possible to contribute to improving the quietness of the onboard internal combustion engine.

Hereinafter, an embodiment in which a chain according to the present invention is embodied as a timing chain of an in-vehicle internal combustion engine will be described with reference to FIGS.
FIG. 1 shows a mounted state of the timing chain 30 with respect to the in-vehicle internal combustion engine. As shown in FIG. 1, the crankshaft 10 of the internal combustion engine is provided with a crank sprocket 11 at the end thereof (lower part of FIG. 1). An intake cam sprocket 22 (upper left portion in FIG. 1) is provided at the end of the intake cam shaft 21, and an exhaust cam sprocket 24 (upper right portion in FIG. 1) is provided at the end of the exhaust cam shaft 23. Yes. A timing chain 30 is engaged with the crank sprocket 11, the intake cam sprocket 22, and the exhaust cam sprocket 24 while being engaged with each other. The rotational force of the crank sprocket 11 is transmitted to the intake cam sprocket 22 and the exhaust cam sprocket 24 by the timing chain 30, and the intake cam shaft 21 and the exhaust cam shaft 23 rotate together with the intake cam sprocket 22 and the exhaust cam sprocket 24. As a result, the intake valve and the exhaust valve (both not shown) are opened and closed.

  FIG. 2 is a partial cross-sectional view of the timing chain 30. As shown in FIG. 2, the pair of outer link plates 41 arranged to face each other are formed with a pair of press-fit holes 41a at predetermined intervals in the longitudinal direction, and the press-fit holes 41a A pair of pins 43 is press-fitted and both ends thereof are fixed. On the other hand, in the pair of inner link plates 42, press-fit holes 42a are formed at predetermined intervals in the longitudinal direction, and a pair of bushes 44 are press-fitted into the press-fit holes 42a, and both end portions thereof are fixed. Yes. Pin holes 44a are formed in the bush 44, and pins 43 are inserted into the pin holes 44a. As a result, the pair of outer link plates 41 and the pair of inner link plates 42 are rotatable about the pin 43 and alternately alternate along the traveling direction of the timing chain 30 such that their respective end portions overlap. It is connected.

  Here, as the timing chain 30 travels, the outer link plate 41 and each pin 43 fixed to the outer link plate 41 are pulled in the traveling direction (the direction indicated by the arrow F in the figure). At this time, the bush 44 into which the pin 43 is inserted is subjected to a relatively large load from the pin 43 on the portion located on the arrow F side. In contrast, the load acting on the portion of the bush 44 located on the opposite side of the arrow F, in other words, the portion located between the pins 43 in the longitudinal direction of the inner link plate 42 is relatively small. Therefore, in the present embodiment, the bush 44 has a shape corresponding to such a load by reducing the thickness of the portion where the load is smaller than the thickness of the portion where the load acting on the bush 44 is large. I have to.

  The shape of the bush 44 will be described in more detail with reference to FIG. 3 is a cross-sectional view taken along the line AA in FIG. As shown in FIG. 3, the bush 44 and the pin 43 both have a circular cross section. Here, a pin hole 44 a is formed in the bush 44 at a position that is eccentric by a predetermined distance (= δ) inward from the center of the cross section in the longitudinal direction of the inner link plate 42. Thereby, in the longitudinal direction of the inner link plate 42, the thickness of the bush 44 in the portion located between the pair of pins 43 is set to be thinner than the thickness of the portion located on the opposite side. As a result, the thickness of the portion of the bush 44 where the load acting from the pin 43 is small is set thinner than the thickness of the portion where the load is large. The magnitude of the eccentricity δ described above is set to a value with which the portion where the thickness of the bush 44 is thin has enough rigidity to withstand the load acting on it.

  4A is an enlarged cross-sectional view of the bush 44 and the pin 43 inserted through the pin hole 44a in this embodiment, and FIG. 4B is an enlarged cross-sectional view of a conventional general bush and pin. As shown in FIG. 4 (b), the conventionally adopted bush has a circular cross section and a pin hole through which a pin is inserted at the center of the cross section. Therefore, the wall thickness around the pin hole of the bush is set to be equal over the entire circumference, and the portion of the bush located between the pair of pins, that is, the portion of the bush where the load acting from the pin is small. The thickness L2 is equal to the thickness L1 of the portion located outside each pin, that is, the portion where the load acting from the pin is large. Here, the thickness L1 of the portion of the bush where the load acting from the pin is large is set to a value that can withstand the load, so the thickness L2 of the portion located between the pair of pins is the load acting on this. Although it is small, it is set too thick with respect to the load.

  On the other hand, in the bush 44 according to the present embodiment shown in FIG. 4A, the thickness L1 of the portion positioned outside each pin 43 in the longitudinal direction of the inner link plate 42 is the same as described above. While it is set equal to the wall thickness L1 of the conventional bush shown in FIG. (B), the wall thickness L2 of the portion located between the pins 43 is set thinner than the wall thickness L2 of the conventional bush. Therefore, the bush 44 according to the present embodiment can be set to a smaller outer diameter while ensuring the necessary rigidity as compared with the conventional one, and the weight can be reduced.

According to the embodiment described above, the following effects can be obtained.
(1) The pair of bushes 44 provided on the pair of inner link plates 42 has a thickness L2 between the pair of pins 43 in the longitudinal direction of the inner link plate 42, that is, the side where the acting load is small. It has a shape that is thinner than the wall thickness L1 on the outside, that is, the side where the acting load is large. For this reason, the wall thickness L1 on the side where the load acting on the bush 44 is large can be kept as it is, and only the wall thickness L2 on the side where the load is small can be reduced, and the necessary rigidity against the load acting on the bush 44 can be maintained. However, it is possible to reduce the weight of the bush 44, in other words, to reduce the weight of the entire timing chain 30. Therefore, the meshing noise can be suppressed by reducing the impact at the time of meshing while maintaining the rigidity of the timing chain 30.

  (2) The pair of bushes 44 has a circular cross section, and the pin holes 44a are formed at positions eccentric to the side closer to each other than the center of each bush 44 in the longitudinal direction of the pair of inner link plates 42. . For this reason, in the bush 44 having a circular cross section, the center position of the pin hole 44a is decentered to the side where the load acting on the bush 44 from the pin 43 is small in the longitudinal direction of the inner link plate 42. In the direction, the thickness L1 on the side where the load applied to the bush 44 is large can be maintained, the thickness L2 on the side where the load is small can be reduced, and the rigidity corresponding to the load applied to the bush 44 can be maintained and the timing chain 30 can be maintained. The overall weight can be reduced.

  (3) Generally, in an in-vehicle internal combustion engine, the crankshaft rotates at a relatively high speed, so that the occurrence of noise due to the inertia of the chain as described above becomes significant. In addition, quietness is strongly desired for in-vehicle internal combustion engines. In this regard, according to the present embodiment, the rotational force of the crank sprocket 11 provided on the crankshaft 10 of the in-vehicle internal combustion engine is used for the exhaust cam provided on the intake cam sprocket 22 and the exhaust camshaft 23 provided on the intake camshaft 21. By applying the present invention as the timing chain 30 for transmitting to the cam sprocket 24, it is possible to suppress the generation of noise accompanying the traveling of the timing chain 30, and to contribute to the improvement of the quietness of the in-vehicle internal combustion engine. It becomes like this.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
In the above embodiment, a bush having a circular cross section is illustrated, but the bush may have other cross sectional shapes. For example, as shown by the broken line in FIG. 5, the thickness of the portion located between the pair of pins 43 in the longitudinal direction of the inner link plate 42 withstands the load acting on that portion, based on the circular cross section. It is also possible to employ a bush 45 having a cross-sectional shape that has been cut to a minimum possible size. Incidentally, in this case, the external teeth of the sprocket that meshes with the bush 45 need to have a shape corresponding to the cross-sectional shape of the bush 45. As shown in FIG. 6, even if the bush 46 has a rectangular cross section, the thickness of the bush 46 in the portion located between the pair of pins 43 in the longitudinal direction of the inner link plate 42 is on the opposite side. If the thickness is set to be thinner than the thickness of the portion located outside each pin 43, the thickness corresponds to the acting load, and therefore the same effect as in the above embodiment can be obtained.

  In addition, the present invention can also be applied to a timing chain having a roller. Hereinafter, this case will be described with reference to FIGS. 7 and 8 focusing on differences from the above embodiment. 7 shows a partial cross-sectional view of the timing chain 30, and FIG. 8 shows an enlarged cross-sectional view along the line BB in FIG. As shown in FIGS. 7 and 8, a roller 47 is fitted on the bush 44 of the timing chain 30. The roller 47 has a circular cross section as shown in FIG. 8, and the center thereof coincides with the center of the bush 44. Accordingly, the roller 47 has a uniform thickness over the entire circumference in the circumferential direction. On the other hand, the bush 44 has a pin hole 44a formed at a position eccentric from the center thereof, as in the embodiment described above. According to such a configuration, the outer diameter of the bush 44 can be further reduced even when the thickness of the roller 47 is set to a minimum to reduce the weight. Therefore, the weight of the entire timing chain 30 can be reduced, and the generation of noise can be suppressed.

  -Although the example which applied this invention to the timing chain of the vehicle-mounted internal combustion engine was shown in the said embodiment, this invention is not restricted to this, It can also apply to the chain used for another use.

The front view which shows the mounting state of the timing chain with respect to a vehicle-mounted internal combustion engine. The fragmentary sectional view which shows the partial cross section structure of a chain. AA sectional drawing of FIG. (A), (b) The expanded sectional view which shows the expanded sectional structure of a chain. Sectional drawing which shows the example of a change about a chain. Sectional drawing which shows the example of a change about a chain. Sectional drawing which shows the example of a change about a chain. BB sectional drawing of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Crankshaft, 11 ... Crank sprocket, 21 ... Intake camshaft, 22 ... Intake cam sprocket, 23 ... Exhaust camshaft, 24 ... Exhaust cam sprocket, 30 ... Timing chain, 41 ... Outer link plate, 42 ... Inner link plate 41a, 42a ... press-fitting hole, 43 ... pin, 44, 45, 46 ... bush, 44a ... pin hole, 47 ... roller.

Claims (4)

A pair of inner plates, and a pair of ends that are fixed to the pair of inner plates and that have pin holes penetrating from one side of the pair of inner plates to the other, are provided at each end of the pair of inner plates. A pair of outer plates, a pair of outer plates provided on the outer side of the inner plate so that the ends overlap, and a pair of outer plates inserted into the pin holes of the bush. A chain comprising a pair of pins to which the portion is fixed, wherein the inner plate and the outer plate are alternately connected,
The pair of bushes provided on the pair of inner plates has a shape in which the portion located between the pair of pins in the longitudinal direction of the inner plate is thinner than the portion located outside the pins. A chain characterized by The chain according to claim 1,
The chain is characterized in that the pair of bushes has a circular cross section, and the pin holes are formed at positions eccentric to the side closer to each other than the center of each bush in the longitudinal direction of the pair of inner plates. The chain according to claim 2,
A roller is rotatably fitted around the pair of bushes. In the chain according to any one of claims 1 to 3,
The chain is a timing chain for transmitting a rotational force of a crank sprocket provided on a crankshaft of an in-vehicle internal combustion engine to a cam sprocket provided on a camshaft.

Images