JP6362946B2 - Chain transmission - Google Patents

Description

  The present invention relates to a chain transmission for driving a camshaft.

  In a chain drive device for driving a camshaft that spans a chain between a crank sprocket attached to the crankshaft and a cam sprocket attached to the camshaft, the chain travels on one side of the slack side chain in the chain. A swingable chain lever extending in the direction is provided, and an adjustment force of a chain tensioner is applied to the swing side end portion of the chain lever to tension the chain to prevent the chain from loosening or fluttering.

  In addition, a fixed chain guide is provided in the chain on the tension side of the chain, and the movement of the chain is guided by the chain guide to suppress fluttering.

  Here, in the chain transmission device described in Patent Document 1, a plurality of rolling bearings are provided on the chain lever, and the chain is rolled and guided by the rolling bearings. Such chain guidance by rolling has the characteristics that the movement resistance of the chain is small and the torque transmission loss is small.

International Publication No. 2010/090139

  By the way, like the chain transmission device described in Patent Document 1, there is a problem that the chain is greatly bent and the sound is deteriorated by making the guide of the chain rolling. When various tests were conducted to determine the cause, the chain was bent at each position where it contacted the rolling bearing, and the chain lever vibrated due to the collision of the chain against the outer periphery of the rolling bearing. It was found that the vibration was applied to the chain tensioner, causing the engine to vibrate.

  Furthermore, when the cause of the sound deterioration was analyzed with the chain lever and chain guide, it was found that the main factor was the chain lever.

  Some types of chain guide are based on sliding contact, and the type based on the sliding contact guide is extremely less in comparison with the case in which the chain collides with the rolling guide and the impact force is weak. Therefore, it can be said that sound is a problem unique to rolling guidance, but it is still a problem even with a sliding contact type.

  Here, in International Publication No. 2009/034950, an elastic pressing member is attached to the tip of the plunger of the chain tensioner, the chain lever is pressed by the pressing member, and the impact at the time of pressing is elastically deformed by the elastic member. However, nothing is described about the suppression of vibration propagation from the chain tensioner to the engine block.

  Japanese Patent Application Laid-Open No. 2002-70963 attaches a pad having a spring characteristic to a portion pressed by a plunger of a chain tensioner of a chain lever, and absorbs a change in the span length of the chain by the pad, thereby vibrating the chain. A chain tensioner device that suppresses vibration is described, but nothing is described about suppression of vibration propagation from the chain tensioner to the engine block.

  An object of the present invention is to reduce vibration by suppressing vibration propagation from a chain tensioner to an engine in a chain transmission for driving a camshaft.

  In order to solve the above problems, in the present invention, a swingable chain lever for guiding the movement of the chain is provided around the camshaft drive chain, and a chain tensioner is provided at the swing side end of the chain lever. In a chain transmission that applies the adjustment force of the chain and urges the chain lever toward the chain, the vibration is transmitted from the chain tensioner to the engine block between the opposed portion of the engine block to which the chain tensioner is attached and the chain tensioner. A configuration provided with suppression means for suppressing vibration propagation is employed.

  As described above, by providing the vibration propagation suppressing means between the opposed portions of the engine block and the chain tensioner, vibration propagation from the chain tensioner to the engine block can be suppressed, and noise generation can be suppressed.

Here, as the vibration propagation suppressing means, one having the following configurations I to IV can be adopted.
Configuration I: An anti-vibration member having elasticity is installed between the opposing surfaces of the chain tensioner and the engine block, and the vibration applied to the chain tensioner is absorbed and attenuated by the elastic deformation of the anti-vibration member, so that the vibration is propagated to the engine block. Suppressed configuration.
Configuration II: A structure in which a collar is incorporated into each of the plurality of attachment portions of the chain tensioner to the engine block, and the contact area is reduced as the mounting of each of the collars on the engine block to suppress vibration propagation to the engine block. thing.
Configuration III: Protrusions are provided at each of the attachment parts of the chain tensioner to the engine block, and each leg is attached to the engine block to reduce the contact area and propagate vibration to the engine block. The thing of the composition which suppresses.
Configuration IV: A plate-shaped vibration isolating member having elasticity is incorporated between the opposed surfaces of the chain tensioner and the engine block, and the chain tensioner has a height higher than the plate thickness of the vibration isolating member at each of a plurality of attachment portions to the engine block. Low-projection-shaped leg portions, each of which is inserted into an insertion hole formed in the vibration-proof member and seated on the engine block, and is loaded on the chain tensioner by elastic deformation of the vibration-proof member. A configuration that absorbs and attenuates vibration and suppresses vibration propagation to the engine block by reducing the contact area with the engine block.

  In adopting the vibration propagation inhibiting means of the above configuration I, it is preferable that the vibration isolating member is made of an elastic body excellent in heat resistance and vibration propagation inhibiting effect. Examples of such elastic bodies include nitrile rubber, hydrogenated nitrile rubber, silicon rubber, and acrylic rubber.

  In the chain transmission device according to the present invention, the chain lever may be provided with a shoe that slides and guides the chain. However, since the sliding resistance is large and the torque transmission loss is large, the chain is guided to roll the chain. It is preferable to employ one having a plurality of bearings.

  In the present invention, as described above, the vibration propagation suppression means is provided between the opposed portions of the engine block and the chain tensioner, thereby suppressing the vibration propagation from the chain tensioner to the engine block and suppressing the generation of noise. Can do.

Schematic showing an embodiment of a camshaft drive chain transmission according to the present invention Sectional view along the line II-II in FIG. Sectional drawing which shows the other example of a vibration propagation suppression means Sectional drawing which shows another example of vibration propagation suppression means Sectional drawing which shows another example of vibration propagation suppression means

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the camshaft drive chain transmission device has a chain 5 between a crank sprocket 2 attached to the shaft end of the crankshaft 1 and a cam sprocket 4 attached to the shaft end of the camshaft 3. The rotation of the crankshaft 1 is transmitted to the camshaft 3 to rotate the camshaft 3.

  Here, the chain 5 may be a roller chain or a silent chain.

  The crankshaft 1 rotates in the direction indicated by the arrow in FIG. The rotation of the crankshaft 1 causes the chain 5 to move in the direction indicated by the arrow in the figure, the portion moving upward is the slack side chain 5a, and the portion moving downward is the tension side chain 5b. A chain lever 10 for tension adjustment is provided on one side of the slack side chain 5a. Further, a chain guide 20 for movement guidance is provided on the other side of the tension side chain 5b.

  The chain lever 10 has a curved shape extending long in the moving direction of the chain 5, and one end portion located on the upper side thereof is supported by a fulcrum shaft 12 projecting from the engine block 11 shown in FIG. The lower end of the swing side is loaded with an adjustment force of the chain tensioner 13 and is biased toward the slack side chain 5a.

  The chain lever 10 may guide the surface of the chain 5 with a shoe, or, as shown in FIG. 1, by each of a plurality of rolling bearings 6 provided at intervals in the moving direction of the chain 5. It may be a rolling guide.

  The chain tensioner 13 has a plurality of attachment pieces 13 a, and the attachment pieces 13 a are attached to the engine block 11 by tightening bolts 14 that are screwed into the engine block 11.

  As shown in FIG. 2, the chain tensioner 13 is mounted so as to incorporate a plate-like vibration isolating member 15 between the chain tensioner 13 and the engine block 11. As the vibration isolating member 15, a member made of an elastic body excellent in heat resistance and vibration propagation suppressing effect is employed. Examples of such elastic bodies include nitrile rubber, hydrogenated nitrile rubber, silicon rubber, and acrylic rubber.

  The chain tensioner 13 is a hydraulically sealed type in which the swing side end of the chain lever 10 is pressed toward the chain 5 by the plunger 13b and the pushing force from the chain 5 is buffered by a hydraulic damper. Yes. Instead of such a hydraulically sealed chain tensioner, a spring-type chain tensioner that does not use hydraulic pressure may be employed.

  As shown in FIG. 1, the chain guide 20 has a curved shape extending in the moving direction of the chain 5, and both ends thereof are fixed to the engine block 11 by tightening bolts 21. As the chain guide 20, one that guides the surface of the chain 5 is employed, but as with the chain lever 10, the chain guide 20 may be one that performs rolling guidance using a plurality of rolling bearings.

  The chain transmission device for driving the cam shaft shown in the embodiment has the above-described structure, and when driving the chain 5 by rotating the crank sprocket 2 to rotate the cam shaft 3, When the chain 5 vibrates due to the collision of the chain 5 with the rolling bearing 6 or the like, the vibration is propagated from the chain lever 10 to the chain tensioner 13.

  At this time, if the vibration of the chain tensioner 13 is propagated to the engine block 11, a large noise is generated. However, in the embodiment, since the vibration isolating member 15 having elasticity is incorporated between the opposed portions of the chain tensioner 13 and the engine block 11, the vibration isolating member 15 is elastic when vibration is propagated to the chain tensioner 13. It is deformed and the vibration is absorbed and damped. The generation of noise is suppressed by the attenuation of the vibration.

  In FIG. 2, the vibration preventing member 15 is incorporated between the opposed portions of the engine block 11 and the chain tensioner 13 to suppress the vibration propagation. However, the vibration propagation inhibiting means is not limited to the incorporation of the vibration preventing member 15. . 3 to 5 show other examples of vibration propagation suppressing means.

  In the example shown in FIG. 3, a collar 16 is incorporated between each of the plurality of mounting pieces 13a of the chain tensioner 13 and the opposed portion of the engine block 11, and the engine block 11 is mounted as an attachment for seating the collar 16 on the engine block 11. The contact area of the chain tensioner 13 with respect to 11 is reduced, and vibration propagation to the engine block 11 is suppressed.

  In the example shown in FIG. 4, each of the plurality of attachment pieces 13 a of the chain tensioner 13 is provided with a protruding leg portion 13 c, and the contact area is reduced by attaching each of the leg portions 13 c to the engine block 11. The vibration propagation to the engine block 11 is suppressed.

  In the example shown in FIG. 5, a plate-shaped vibration isolating member 15 having elasticity is incorporated between opposed surfaces of the chain tensioner 13 and the engine block 11, and the vibration isolating member 15 is attached to each of the plurality of attachment pieces 13 a in the chain tensioner 13. A projection-like leg portion 13c having a height lower than the plate thickness is provided, and each leg portion 13c is inserted into an insertion hole 15a formed in the vibration isolating member 15 so as to be seated on the engine block 11, and vibration isolation The vibration applied to the chain tensioner is absorbed and damped by the elastic deformation of the member 15, and the vibration propagation to the engine block 13 is suppressed by reducing the contact area with the engine block 11. In any of FIGS. 3 to 5, the generation of noise can be suppressed.

5 Chain 6 Rolling bearing (bearing)
10 Chain lever 11 Engine block 13 Chain tensioner 13c Leg part 15 Anti-vibration member 15a Insertion hole 16 Collar

Claims (4)

A swingable chain lever (10) for guiding the movement of the chain (5) is provided around the camshaft drive chain (5), and a chain tensioner ( 13) In the chain transmission in which the adjusting force of 13) is applied and the chain lever (10) is urged toward the chain (5),
The chain tensioner (13) an engine block attached (11) between opposing portions of the chain tensioner (13), to suppress the vibration propagation suppressing unit vibration propagation from the chain tensioner (13) to the engine block (11) Provided ,
The vibration propagation restraining means is provided with a protruding leg (13c) at each of a plurality of attachment portions of the chain tensioner (13) to the engine block (11), and the leg (13c) is attached to the engine block (11 ) chain transmission device comprising a benzalkonium such a configuration in which a mounting for seating on. A swingable chain lever (10) for guiding the movement of the chain (5) is provided around the camshaft drive chain (5), and a chain tensioner ( 13) In the chain transmission in which the adjusting force of 13) is applied and the chain lever (10) is urged toward the chain (5),
The chain tensioner (13) an engine block attached (11) between opposing portions of the chain tensioner (13), to suppress the vibration propagation suppressing unit vibration propagation from the chain tensioner (13) to the engine block (11) Provided ,
The vibration propagation restraining means incorporates a plate-shaped vibration isolating member (15) having elasticity between opposed surfaces of the chain tensioner (13) and the engine block (11), and the engine is installed in the chain tensioner (13). Protruding leg portions (13c) having a height lower than the plate thickness of the vibration isolating member are provided at each of the plurality of attachment portions with respect to the block (11), and each of the leg portions (13c) is attached to the vibration isolating member (15). ) was inserted into the formed insertion hole (15a) in the mounting to be seated on the engine block (11) a chain transmission device comprising a kite. The chain transmission according to claim 1, wherein the leg is a collar (16). The chain transmission device according to any one of claims 1 to 3 , wherein the chain lever (10) includes a plurality of bearings (6) for rolling and guiding the chain (5).

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