JP5437607B2 - Chain and chain-type power transmission system - Google Patents

Description

  The present invention relates to a structure for reducing sliding friction between a chain and a chain guide.

  Some engines use a chain (timing chain) for power transmission from a crankshaft to a camshaft. Usually, a chain guide (guide member) is applied as a tensioner to the span of the timing chain in order to maintain an appropriate tension. Since the chain is in sliding contact with the chain guide, a friction loss is generated between the chain and the chain guide, which increases as the engine speed increases. That is, when the traveling speed of the chain increases due to an increase in the engine speed, the centrifugal force of the chain increases and the vertical drag applied from the chain to the chain guide increases, so that the friction between the chain and the chain guide increases. For these reasons, it is desired to reduce the sliding friction between the chain and the chain guide in order to improve the fuel consumption of the engine.

In order to reduce the frictional resistance, the height of the outer link plates of the link plates that are alternately connected to each other is made lower than the height of the inner link plate, so that the link plate contacting the guide member is used as the inner link plate only and the friction loss is reduced. Has been proposed (Patent Document 1).
JP 2007-107583 A

  However, in the configuration of Patent Document 1, it is necessary to change the shapes of the inner link plate and the outer link plate and to connect them alternately, which makes the manufacturing process complicated and increases the cost.

  An object of the present invention is to reduce the friction loss between a chain and a chain guide with a simple configuration.

  The chain transmission system of the present invention includes a chain formed by connecting link plates, and a guide member that slides in contact with the end surface of the link plate and guides the travel of the chain, and the end surface of the link plate along the link plate thickness direction. The contact area between the guide member and the sliding contact surface of the guide member is reduced.

  For example, the cross-sectional shape of the end face in the link plate thickness direction includes a curved portion, and the contact area is reduced. The curved portion includes those in which at least one edge portion of the end face is rounded. In addition, the curved portion may include those in which both edge portions of the end face are rounded. Alternatively, the curved portion may include a groove along the longitudinal direction of the end surface.

  Further, in order to reduce the contact area, a plurality of grooves along the running direction of the chain may be formed on the sliding contact surface at intervals narrower than the link plate thickness.

  The chain of the present invention is a chain used in a chain transmission system that includes a guide member that is in sliding contact with an end surface of a link plate of the chain and guides the travel of the chain, and is provided on the link plate along the link plate thickness direction. The contact area between the end surface and the sliding contact surface of the guide member is characterized in that the cross-sectional shape of the end surface in the link plate thickness direction is provided with a curved portion.

  The guide member of the present invention is a guide member that slides in contact with the end face of the link plate of the chain and guides the travel of the chain in the chain type transmission system, and the end face of the link plate along the link plate thickness direction and the guide member The contact area with the sliding surface is reduced by forming a plurality of grooves along the running direction of the chain at intervals smaller than the link plate thickness on the sliding surface.

  As described above, according to the present invention, the friction loss between the chain and the chain guide can be reduced with a simple configuration.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing a configuration of a chain type power transmission system according to a first embodiment of the present invention.

  In the present embodiment, the chain type power transmission system 10 is used as a timing drive system for an internal combustion engine that transmits power from a crankshaft 11 to a camshaft 12. The timing chain (chain) 13 is wound around a crankshaft sprocket (driving sprocket) 14 and a camshaft sprocket (driven sprocket) 15, and a chain span connecting the crankshaft sprocket 14 and the camshaft sprocket 15 is a chain guide (guide member). ) 16, 17

  One end of the chain guide 16 is pivotally attached to the engine block with the rotation shaft 16A as a center and is urged to rotate about the rotation shaft 16A by using a biasing member 18 using a spring, hydraulic pressure, or the like. That is, the chain guide 16 functions as a tensioner lever that presses the timing chain 13 and adjusts the tension of the timing chain 13. The chain guide 17 is fixed to, for example, an engine block.

  2 is a partially enlarged view of the timing chain 13, FIG. 2 (a) is a plan view, and FIG. 2 (b) is a side view.

  As is conventionally known, the timing chain 13 is configured by alternately connecting a pair of inner link plates 19 and a pair of outer link plates 20. In the present embodiment, plates having substantially the same shape are used for the inner link plate 19 and the outer link plate 20. Each of the link plates 19 and 20 has, for example, a shape in which both ends of a rectangular thin plate member are formed in a substantially semicircular shape, and holes 19A and 20A are provided at both ends, respectively.

  The end portions of the pair of inner link plates 19 are arranged inside the end portions of the outer link plates 20 so as to overlap with the holes 20A of the pair of outer link plates 20 to which the holes 19A are connected. , 20A, pins 21 are respectively inserted. As described above, the inner link plate 19 and the outer link plate 20 are alternately connected by the pins 21 so as to be rotatable. Further, the timing chain 13 of the present embodiment is, for example, a roller chain, and a roller 22 is mounted around each pin 21. A bush is usually inserted between the pin 21 and the roller 22, but is omitted in the figure.

  FIG. 3 is a cross-sectional view showing the relationship between the timing chain 13 that contacts the chain guide 16 (or 17) and the chain guide 16 (17). As shown in FIG. 3, the timing chain 13 is in sliding contact with the sliding contact surface 24 of the chain guide 16 (17) at the end surface 23 along the chain longitudinal direction of the link plate 19 (or 20), and the chain guide 16 ( 17).

  FIG. 4 is an enlarged view of the cross-sectional shape of the link plate 19 (20) on the left side of FIG. Since the end surface along the longitudinal direction of the conventional link plate is a flat surface, the link plate contacts the sliding contact surface of the chain guide over the thickness t along the link plate thickness direction. . On the other hand, in this embodiment, a radius (R) is provided at one edge portion of the end surface 23 of the link plate 19 (20). In the example of FIG. 3, rounds are provided on the outer edge portions of the end face 23 of the link plate 19 (20) arranged on both sides.

  Contact is provided along the plate thickness direction between the link plates 19 and 20 and the chain guide 16 (17) by providing a radius at one edge portion of the end face 23 along the longitudinal direction of the link plates 19 and 20. The area can be smaller than when contacting over the entire plate thickness.

  In addition, when providing a round only in the edge part of one side like this embodiment, it is also possible to form a link plate by a die cutting process and to provide a round in advance in this die cutting process. Further, after the link plate is formed by punching, the edge portion may be subjected to mechanical processing such as polishing to form a radius.

  As described above, according to the first embodiment, by providing a radius (curved portion) at the edge portion of the other surface along the chain longitudinal direction of the link plate, the end surface of the link plate along the link plate thickness direction The contact area between the sliding surface of the chain guide is reduced. Thereby, the film formation of the lubricating liquid between the link plate end surface and the sliding contact surface of the chain guide can be promoted, the frictional resistance can be reduced, and the friction loss can be reduced. Further, by reducing the contact area, the surface pressure increases, and the link plate can be smoothed at an early stage by contact with the sliding contact surface, and the friction coefficient can be reduced.

  Next, FIG. 5 shows a modification of the first embodiment. In this modification, R (R) is provided at both edge portions of the end surfaces 23 of the link plates 19 and 20. Thus, even if the round (R) is provided at both edge portions of the other surface 23, the same effect as in the first embodiment can be obtained.

  In addition, although it was set as the structure which provides a round at an outer edge part in 1st Embodiment, the structure which provides a round at an inner edge part may be sufficient. Further, it is possible to use only one link plate as an edge portion where a round is provided, or one link plate is provided with a round on the outside and the other is provided on the inside, or a combination of these and the configuration of the modified example. It is also possible.

  Next, a second embodiment of the present invention will be described with reference to FIG. The second embodiment is the same as the first embodiment with respect to the other configurations, except that the shape of the end face 23 of the link plate in the first embodiment is different. Therefore, only the configuration different from the first embodiment will be described with reference to FIG.

  FIG. 6 is a cross-sectional view of the link plate corresponding to FIGS. 4 and 5 in the first embodiment and its modification. The end face 26 along the longitudinal direction of the chain of the link plate (including the inner side and the outer side) 25 of the second embodiment has at least one groove (curved portion) along the longitudinal direction instead of providing a rounded edge. 27), and three grooves 27 are formed on the end face 26 in the example of FIG.

  As described above, also in the second embodiment, the contact area along the thickness direction of the link plate can be made smaller than in the case where the end face is a plane, as in the first embodiment, and the same effect as in the first embodiment. Can be obtained.

  Next, a third embodiment of the present invention will be described with reference to FIG. In the first and second embodiments, the curved plate is provided on the end surface of the link plate to reduce the contact area along the link plate thickness direction between the link plate and the chain guide. In the embodiment, the contact area is reduced by processing the sliding contact surface of the chain guide.

  FIG. 7 is a view corresponding to FIGS. 4 to 6, and is a cross-sectional view of the link plate and the chain guide along a plane perpendicular to the chain traveling direction. In the third embodiment, the link plate 28 has a flat end surface 29 along the longitudinal direction. On the other hand, the sliding contact surface 31 of the chain guide 30 is provided with a plurality of grooves 32 along the chain traveling direction. The grooves 32 are cut at an interval narrower than the thickness t of the link plate 28. That is, the end surface 29 always faces at least one groove 32, and the contact area between the end surface 29 and the sliding contact surface 31 is reduced compared to when the end surface 29 and the sliding contact surface 31 are flat.

  As described above, also in the third embodiment of the present invention, the same effects as those in the first and second embodiments can be obtained.

  In this embodiment, as shown in FIG. 1, since the chain guide is in sliding contact with only the outer end surface of the chain, the processing on the end surface of the chain in the first embodiment, the modified example, and the second embodiment is performed on the outer side. However, when the chain guide is also slidably contacted with the inner end surface, the same processing is performed on the inner end surface.

  In this embodiment, the end face of the link plate is parallel and linear along the longitudinal direction of the chain. However, a thin plate member with a central portion that is conventionally known acts on the link plate. Also good. In the present embodiment, the roller chain has been described as an example, but the chain may be of other types.

It is a mimetic diagram showing composition of a chain type power transmission system which is a 1st embodiment of the present invention. It is the elements on larger scale of a timing chain, and a side view. It is a cross-sectional view which shows the relationship between the timing chain which contacts a chain guide, and a chain guide. It is a figure which shows the cross-sectional shape of the link plate of the left side of FIG. It is a figure which shows the cross-sectional shape of the link plate of the modification of 1st Embodiment. It is a figure which shows the cross-sectional shape of the link plate and chain guide in the chain type power transmission system of 2nd Embodiment of this invention. It is a figure which shows the cross-sectional shape of the link plate and chain guide in the chain type power transmission system of 3rd Embodiment of this invention.

Explanation of symbols

10 Timing drive system (chain power transmission system)
13 Timing chain 14 Crankshaft sprocket 15 Camshaft sprocket 16, 17 Chain guide (guide member)
19 Inner link plate 20 Outer link plate 23 End surface 24, 31 Sliding surface 27 Groove 32 Groove

Claims (8)

  A chain formed by connecting link plates; and a guide member that slides in contact with an end surface of the link plate and guides the travel of the chain; and the link plate thickness of the end surface of the link plate along the link plate thickness direction. A chain-type transmission system characterized in that the cross-sectional shape in the direction is a curved shape, so that the contact with the sliding contact surface of the guide member is a line contact, and the contact area is reduced.   The chain-type transmission system according to claim 1, wherein the curved shape includes a curved shape at least one edge portion of the end face.   The chain-type transmission system according to claim 2, wherein the round shape is provided only at an outer edge portion of the link plate.   The chain type transmission system according to claim 2, wherein the curved shape includes a shape in which both edge portions of the end face are rounded.   The chain-type transmission system according to claim 2, wherein the curved shape includes a groove along a longitudinal direction of the end face. A chain formed by connecting link plates; and a guide member that slides in contact with an end surface of the link plate and guides the travel of the chain; and the end surface of the link plate or the guide member along the thickness direction of the link plate A plurality of grooves along the running direction of the chain are formed on the sliding contact surface at intervals narrower than the link plate thickness, and the contact between the link plate and the sliding contact surface is defined as line contact. Chain transmission system characterized by reduced area.   A chain used in a chain transmission system including a guide member that guides the travel of the chain in sliding contact with an end surface of a link plate of the chain, the end surface of the link plate along the link plate thickness direction and the guide A chain in which a contact area with a sliding surface of a member is reduced by making a cross-sectional shape of the end surface in a link plate thickness direction a curved shape and making the contact a line contact.   In a chain transmission system, a guide member that is in sliding contact with an end surface of a link plate of a chain and guides the travel of the chain, the end surface of the link plate along the thickness direction of the link plate and a sliding contact surface of the guide member The contact area between the contact plate and the sliding contact surface is reduced by forming a plurality of grooves along the running direction of the chain at intervals smaller than the link plate thickness, and making the contact a line contact. A guide member for a chain-type transmission system.

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