JP2006207779A - Behavior restrain device of timing chain - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a behavior restrain device of a timing chain, restraining displacement behavior at a hanging part of the timing chain between cam sprockets, thereby effectively reducing chain hammering sound and new hammering sound due to tramping. <P>SOLUTION: This behavior restrain device of the timing chain includes: a timing chain side plate 41 having a sliding contact part 40 brought into sliding contact with a hanging part 24c of the timing chain 24 between the cam sprockets 22, 23; a counter-timing chain side plate 43 having a shaft 42 rotatably supporting one side end of the timing chain side plate; a spring 44 energizing the timing chain side plate to follow up the downward displacement behavior of the hanging part when the hanging part slacks; and a damping means 45 for damping the upward displacement behavior of the hanging part by oil in a space 46 between both plates when the hanging part is stretched. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a behavior suppressing device that suppresses the behavior of a timing chain spanned between cam sprockets.

Conventionally, a crank sprocket that is integrally connected to one end of a crankshaft that is driven and rotated in one direction, an intake valve cam sprocket that is integrally connected to one end of an intake valve camshaft, and an exhaust valve camshaft. An exhaust valve cam sprocket that is integrally connected to one end of the engine, and a timing chain that is wound around these sprockets and rotates the intake and exhaust valve cam sprockets by driving the crank sprocket. A tensioner device for adjusting the tension of the timing chain is provided on the slack side, upstream of the cam sprocket in the rotational direction of the timing chain, while the tension on the downstream side of the timing chain in the rotational direction of the other cam sprocket. Side of the chain that guides the timing chain from the outside. What pattern guide is provided are known (e.g., see Patent Document 1). In this case, the tensioner device will move forward with a plunger that moves forward and backward due to hydraulic pressure, etc., because the tension decreases sharply on the slack side of the timing chain during a sudden rotation fluctuation such as when starting rotation or acceleration / deceleration. Alternatively, the tension is adjusted by removing the slack of the timing chain by retreating.
JP 2001-182790 A

  By the way, with the recent increase in output of internal combustion engines, torque fluctuations from the camshafts for intake valves and exhaust valves tend to become prominent. In this case, a displacement behavior has occurred in which the timing chain swings due to torque fluctuation between the intake valve cam sprocket and the exhaust valve cam sprocket. Moreover, the timing chain between such cam sprockets tends to be loosened by the action of gravity, and the displacement behavior tends to become remarkable in combination with torque fluctuation. As a result, the timing chain flutters between cam sprockets, which causes chain hitting noise.

  From this point, we would like to provide a tensioner device between the cam sprocket for the intake valve and the cam sprocket for the exhaust valve. However, such a tension adjusting device can adjust the tension of the timing chain by a plunger that moves forward and backward by hydraulic pressure. Since the adjustment is made, the structure becomes complicated, the cost is increased, and it is very disadvantageous in terms of versatility.

  Therefore, a movable body is provided outside the timing chain between the cam sprockets so that the movable body can move in the direction of the displacement behavior of the timing chain with respect to the stationary body, and the timing chain between the cam sprockets is provided between the stationary body and the movable body. Displacement in the slack direction of the timing chain with a simple configuration at low cost by providing a biasing means such as a spring that urges the timing chain to follow the displacement behavior in the slack direction when the slack occurs A behavior suppressing device that suppresses the behavior is conceivable.

However, in the proposed behavior suppression device, when the tension chain between the cam sprockets suddenly tensions due to torque fluctuations from the intake valve and exhaust valve camshafts, the moving body resists the biasing force of the spring. As a result, the moving body comes into contact with the fixed body vigorously. For this reason, not only can chain hitting due to timing chain flapping between cam sprockets not be reduced, but also new hitting noise when the moving body comes into contact with the fixed body will be an effective countermeasure against hitting. I don't get it.

  The present invention has been made in view of such points, and the object of the present invention is to suppress the timing chain displacement behavior between cam sprockets and effectively reduce chain hitting noise and new hitting sound caused by flapping. It is an object of the present invention to provide a timing chain behavior suppressing device that can be used.

  In order to achieve the above object, the present invention presupposes a timing chain behavior suppressing device that suppresses the behavior of a timing chain spanned between a plurality of cam sprockets housed in a chain cover. When a slack occurs in the timing chain, the biasing means for urging the timing chain to follow the displacement behavior in the slack direction of the timing chain, and when the tension between the cam sprockets becomes tight, the timing chain And a damping means for damping the displacement behavior in the tension direction by the oil collected in the chain cover.

  Due to this specific matter, when the timing chain is displaced to the slack side due to the action of gravity and torque fluctuation between the intake valve cam sprocket and the exhaust valve cam sprocket, the timing chain is driven by the biasing force of the biasing means. The slack in the timing chain is removed following the displacement behavior in the slack direction. On the other hand, when the timing chain is displaced to the tension side due to torque fluctuation between the cam sprockets, even if the timing chain is displaced in the tension direction against the urging force of the urging means, The displacement behavior is effectively suppressed without generating a new hitting sound due to the damping effect by the oil of the damping means collected in the chain cover. This makes it possible to effectively reduce chain hitting noise and new hitting noise caused by timing chain flapping between cam sprockets with a simple and inexpensive configuration that uses the damping effect of oil in the chain cover. It becomes.

  In particular, the following configurations are listed as specifying the configuration of the behavior suppressing device.

  In other words, a timing chain side plate that is in sliding contact with the timing chain, and an anti-timing having a shaft that is fixedly provided on the side opposite to the timing chain of the timing chain side plate and rotatably supports one end of the timing chain side plate. A chain side plate is provided, and the mutually opposing surfaces of the timing chain side plate and the counter timing chain side plate are brought into contact with each other in the direction of displacement behavior of the timing chain.

  Due to this specific matter, when the timing chain is displaced to the slack side due to the action of gravity and torque fluctuation between the cam sprockets, the timing chain side plate is moved in the slack direction of the timing chain by the biasing force of the biasing means. The displacement moves following the displacement behavior, and the slack of the timing chain is removed. On the other hand, when the timing chain is displaced to the tension side due to torque fluctuation between the cam sprockets, even if the timing chain side plate moves in the timing chain tension direction against the urging force of the urging means, The displacement movement to the tension side causes the two plates to come into contact with each other in the direction of the displacement behavior of the timing chain by the oil film stored between the opposing surfaces of the two plates, and a new sound is generated. The effect is suppressed without generating. As a result, with a simple and inexpensive configuration that uses the damping effect of the oil film stored between the opposing surfaces of the two plates, chain hitting noise due to timing chain flapping between each cam sprocket and new It is possible to effectively reduce the hitting sound.

  In particular, the following configuration is listed as a means for specifying the accommodating portion of the biasing means.

  That is, the timing chain side plate and the anti-timing chain side plate are curved with substantially the same curvature that protrudes toward the timing chain, and the surfaces facing each other between the timing chain side plate and the anti-timing chain side plate While forming the space part which stores oil at the time of mutual contact, the biasing means is accommodated in the said space part.

  By this specific matter, the timing chain side plate and the anti-timing chain side plate that are curved with substantially the same curvature that protrudes toward the timing chain side allow oil to be smoothly stored in the hollow portion between the plates, and the plates face each other. It is possible to further exert a damping effect by the oil film between the surfaces to be performed. Moreover, since the urging means is accommodated in the hollow portion for storing the oil, it is not necessary to prepare a separate storage place for accommodating the urging means, and the urging means can be smoothly accommodated by effectively utilizing the hollow portion. It becomes possible.

  In particular, the following configuration is listed as a further effect of damping by oil.

  That is, the timing chain side plate and the counter-timing chain side plate are provided with recesses that substantially overlap each other when the surfaces facing each other contact each other.

  By this specific matter, when the timing chain side plate is displaced following the displacement behavior in the slack direction of the timing chain, the oil that has entered the counter timing chain side plate is smoothly stored in the recess of the timing chain side plate, When the timing chain is displaced in the tensioning direction from this state, the timing chain side plate moves in the tensioning direction of the timing chain while discharging the oil in the recess of the timing chain side plate by applying pressure to the oil in the recess of the timing chain side plate. Due to the displacement and the discharge of oil from the recess of the timing chain side plate, the damping effect by the oil when the timing chain is displaced in the tension direction can be further exhibited.

  In short, by providing damping means that dampens the displacement behavior of the timing chain between the cam sprockets in the tension direction with the oil in the chain cover, the biasing force of the urging means To eliminate slack in the timing chain and effectively suppress the displacement behavior of the timing chain to the tension side without causing new hitting sound due to the damping effect of the oil in the chain cover. With a simple and inexpensive configuration that utilizes the damping effect of oil, it is possible to effectively reduce chain hitting noise and new hitting sound due to timing chain flapping between cam sprockets.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 shows a DOHC type in-line internal combustion engine to which a tension adjusting device according to an embodiment of the present invention is applied. Reference numeral 1 denotes a cylinder block of the in-line internal combustion engine. While being fixed, the oil pan 12 is attached to the lower part.

The cylinder head 11 is provided with an intake camshaft 13 and an exhaust camshaft 14. A crankshaft 15 is disposed below the cylinder block 1. The camshafts 13 and 14 are rotationally driven by the crankshaft 15. This camshaft drive mechanism will be described in detail below.

  The camshaft drive mechanism includes a crank sprocket 21 that is integrally connected to one end of the crankshaft 15 and an intake cam sprocket 22 that is integrally connected to one end of the intake camshaft 13 of the cylinder head 11. And an exhaust cam sprocket 23 rotatably connected to one end of the exhaust cam shaft 14 of the cylinder head 11, and the crank sprocket 21 and the cam sprockets 22, 23. And a timing chain 24 for rotating the cam sprockets 22 and 23 in a driven manner. Although not shown, such a camshaft drive mechanism is covered from the outside by a cover attached to the front surfaces of the cylinder block 1 and the cylinder head 11.

  Here, for example, when the crank sprocket 21 is rotated in the direction indicated by the arrow A in FIG. 1 (clockwise), the timing chain 24 is also rotationally driven in the direction indicated by the arrow B (clockwise). Accordingly, when the rotation start position of the timing chain 24 is the crank sprocket 21, the stretched portion 24a between the crank sprocket 21 and the intake cam sprocket 22 is on the upstream side in the rotation direction, and the exhaust cam sprocket 23, the crank sprocket 21, The tension portion 24b between the two is downstream in the rotational direction. In the timing chain 24, the stretched portion 24a on the upstream side in the rotational direction is the slack side where the slack is most generated, and the stretched portion 24b on the downstream side in the rotational direction is the stretched side where the most tension is generated.

  Further, the timing chain 24 is provided with a chain tensioner device 31 that adjusts the tension in the tension portion 24 a on the upstream side in the rotation direction of the timing chain 24, and the tension portion 24 b on the downstream side in the rotation direction of the timing chain 24. , A chain guide 32 for guiding the timing chain 24 (stretching portion 24b) is provided.

  The chain tensioner device 31 includes a movable guide 31a and a hydraulic actuator 31c. The end of the movable guide 31a on the crank sprocket 21 side (the lower end in FIG. 1) is rotatably supported by the cylinder block 1, and thereby the end on the intake cam sprocket 22 side that becomes a free end. The portion (the upper end portion in FIG. 1) is guided by being pressed from the outside against the stretched portion 24a of the timing chain 24. The hydraulic actuator 31c is provided outside the end of the movable guide 31a on the intake cam sprocket 22 side (to the left of the end in FIG. 1). The hydraulic actuator 31c includes a plunger 31b that protrudes and retracts by hydraulic pressure, and adjusts the tension by pressing the end of the movable guide 31a on the intake cam sprocket 22 side against the stretched portion 24a of the timing chain 24 by the plunger 31b. It is made like that. In this case, the chain tensioner device 31 adjusts the tension by removing the slack of the timing chain 24 in the tension portion 24a on the upstream side in the rotation direction where the slack is most generated when the rotation start position of the timing chain 24 is set to the crank sprocket 21. It is configured as follows.

As a characteristic part of the present invention, as shown in FIGS. 2 to 4, the timing chain 24 includes a stretched portion at a stretched portion 24 c of the timing chain 24 spanned between the cam sprockets 22 and 23. A behavior suppressing device 4 that suppresses the behavior of 24c is provided. The behavior suppressing device 4 includes a synthetic resin sliding contact portion 40 that is in sliding contact with the stretched portion 24c of the timing chain 24 from the outside (above). ) And a timing chain side plate 41 disposed on the outer side (the upper side in FIGS. 1 to 3) of the timing chain side plate 41 on the opposite side to the timing chain side. (The left end in FIG. 3) is a timing when the anti-timing chain side plate 43 having the shaft 42 that rotatably supports the slanting portion 24c of the timing chain 24 between the cam sprockets 22 and 23 is loosened. The chain side plate 41 is made to follow the displacement behavior in the slack direction (downward in FIGS. 1 to 3) of the stretched portion 24c. When tension is applied to the tension portion 24c of the timing chain 24 between the cam sprockets 22 and 23 and the spring 44 as the biasing means for biasing in this way (FIG. 1 to FIG. 3 is provided with a damping means 45 for damping the upward displacement behavior with oil collected in the chain cover. The behavior suppressing device 4 includes a bracket 49 that extends downward from the rear end of the counter-timing chain side plate 43 (the rear side end in FIG. 1 to FIG. 3) and then extends rearward. The anti-timing chain side plate 43 is fixed so as not to move.

  The timing chain side plate 41 and the anti-timing chain side plate 43 are arranged so that the surfaces facing each other in the vertical direction are the displacement behavior directions of the stretched portion 24c of the timing chain 24 between the cam sprockets 22 and 23 (in FIG. 1 to FIG. Direction). Further, the timing chain side plate 41 and the counter-timing chain side plate 43 are curved with substantially the same curvature that protrudes downward (on the stretched portion 24c side of the timing chain 24). Then, in the substantially central part of the timing chain side plate 41 and the anti-timing chain side plate 43, concave portions 41a and 43a having substantially trapezoidal cross sections that substantially overlap each other when the surfaces facing each other vertically contact each other downward. It is recessed. The recess 41a of the timing chain side plate 41 and the recess 43a of the counter timing chain side plate 43 are formed in a bowl shape having different diameters, and the timing chain side plate 41 and the counter timing chain side plate 43 are opposed to each other vertically. When the surfaces to be contacted with each other, the recess 41a of the timing chain side plate 41 having a large diameter covers the recess 43a of the counter timing chain side plate 43 having a small diameter from below. In addition, a space 46 is provided between the recess 41 a of the timing chain side plate 41 and the recess 43 a of the counter timing chain side plate 43 to store oil when the surfaces facing each other contact each other. The space portion 46 is formed so as to be recessed above the substantially central portion of the recess 43 a of the counter-timing chain side plate 43, and the spring 44 is formed in the inside of the space portion 46 and the recess 41 a of the timing chain side plate 41. It is accommodated in a state of being compacted between the bottom surface of the two. In addition, oil collected inside the upper surface side of the recess 43a of the anti-timing chain side plate 43 is placed on the timing chain side at the annular boundary located between the recess 43a and the space 46 of the anti-timing chain side plate 43. An oil communication hole 43b is provided penetrating in the vertical direction inside the recess 41a of the plate 41, that is, into the space 46. In the space 46, the oil through the oil communication hole 43b and the timing chain side plate 41 are collected from the inside of the upper surface side of the recess 43a of the counter timing chain side plate 43 collected by being sprayed by an oil jet (not shown). The other end side (the right end side in FIGS. 1 to 3) is opened to the counter-timing chain side plate 43 when the tension portion 24 c of the timing chain 24 is displaced following the displacement behavior in the slack direction. The oil that jumps in is stored. In this case, the damping means 45 is configured so that the timing chain side plate 41 and the anti-timing chain side plate 43 that are flush with each other in the direction of the displacement behavior of the stretched portion 24c of the timing chain 24 between the cam sprockets 22 and 23 are perpendicular to each other. Are formed by recesses 41a, 43a of the plates 41, 43, a space 46 for storing oil, and an oil communication hole 43b for guiding the oil into the space 46.

Therefore, in the above embodiment, the stretched portion 24c of the timing chain 24 is loosened between the intake valve cam sprocket 22 and the exhaust valve cam sprocket 23 due to the action of gravity and torque fluctuations from the camshafts 13 and 14. When performing the displacement behavior to the side (downward), the timing chain side plate 41 is displaced by following the displacement behavior in the slack direction (downward) of the tension portion 24c of the timing chain 24 by the biasing force of the spring 44, The slack in the stretched portion 24c of the timing chain 24 is removed.

  On the other hand, when the tension portion 24c of the timing chain 24 is displaced between the cam sprockets 22 and 23 to the tension side (upward) due to the torque fluctuation from the cam shafts 13 and 14, it resists the biasing force of the spring 44. Even if the timing chain 24 is displaced in the tension direction (upward), the displacement behavior of the tensioning portion 24c of the timing chain 24 to the tension side is caused between the opposing surfaces of the plates 41 and 43. With the oil coating stored, both the plates 41 and 43 are brought into contact with each other in the direction of the displacement behavior (vertical direction) of the stretched portion 24c of the timing chain 24, and a new sound is generated by the contact between the plates 41 and 43. It is suppressed to an effect without generating. Moreover, when the timing chain side plate 41 is displaced following the displacement behavior in the slack direction of the stretched portion 43 c of the timing chain 43, the oil that has entered the counter-timing chain side plate 43 is recessed in the timing chain side plate 41. When the stretched portion 24c of the timing chain 24 is displaced in the tension direction (upward) from this state, the oil in the recess 41a of the timing chain side plate 41 is moved by the recess 43a of the counter timing chain side plate 43. The timing chain side plate 41 is displaced and moved in the tension direction of the stretched portion 24c of the timing chain 24 while the pressure is exerted on the gas, and the generation of new hitting sound due to the contact of both the plates 41 and 43 becomes more effective. It is suppressed.

  As a result, the damping effect due to the oil film stored between the opposing surfaces of the plates 41 and 43 and the timing chain while discharging the oil in the recess 41a of the timing chain side plate 41 by applying pressure to the oil. The tension portion of the timing chain 24 between the cam sprockets 22 and 23 has a simple and inexpensive configuration utilizing the damping effect of displacing and moving the side plate 41 in the tension direction of the tension portion 24c of the timing chain 24. Chain hitting sound due to flapping of 24c and new hitting sound due to contact between both plates 41 and 43 can be effectively suppressed.

  Moreover, the timing chain side plate 41 and the anti-timing chain side plate 43, which are curved downward (on the stretched portion 24c side of the timing chain 24) and have substantially the same curvature, are in the hollow portion 46 between the plates 41 and 43. The oil is stored smoothly, and the damping effect by the oil coating between the opposing surfaces of the plates 41 and 43 and the oil in the recess 41a of the timing chain side plate 41 is applied to the oil while being discharged. The damping effect of displacing and moving the timing chain side plate 41 in the tension direction of the stretched portion 24c of the timing chain 24 can be further exhibited. Further, since the spring 44 is accommodated in the hollow portion 46 for storing oil, it is not necessary to prepare a separate accommodation place for accommodating the spring 44, and the spring 44 is smoothly accommodated by effectively utilizing the hollow portion 46. be able to.

  In addition, this invention is not limited to the said embodiment, The other various modifications are included. For example, in the above embodiment, the behavior suppressing device 4 that suppresses the behavior of the stretched portion 24c of the timing chain 24 between the intake sprocket 22 and the exhaust sprocket 23 of the serial internal combustion engine has been described. A behavior suppressing device may be provided in the stretched portion of the timing chain between the intake and exhaust sprockets of each bank of the V-type internal combustion engine, and the behavior in the stretched portion may be suppressed. In addition, a behavior suppressing device is provided in the stretched portion of the timing chain between the intake sprocket and the exhaust sprocket in each bank of the DOHC type V-type internal combustion engine so as to suppress the behavior in this stretched portion. It may be.

1 is a front view of a DOHC type in-line internal combustion engine using a timing chain behavior suppressing device according to an embodiment of the present invention. FIG. 5 is a cross-sectional view of the vicinity of the behavior suppressing device taken along line XX of FIG. 4 in a state where the vertically opposed surfaces of the timing chain side plate and the anti-timing chain side plate are flush with each other. FIG. 5 is a cross-sectional view of the vicinity of the behavior suppressing device cut along line XX in FIG. 4 in a state in which the timing chain side plate is displaced following the displacement behavior of the timing chain tension portion toward the slack side. It is the top view which looked at the behavior suppression apparatus from the upper part.

Explanation of symbols

13 Intake camshaft 14 Exhaust camshaft 22 Intake sprocket 23 Exhaust sprocket 24 Timing chain 24c Stretching portion 4 of timing chain between cam sprockets Behavior suppression device 41 Timing chain side plate 41a Recess 42 Shaft 43 Anti-timing chain Side plate 43a Recess 44 Spring (biasing means)
45 Damping means 46 Space

Claims (4)

In the timing chain behavior suppressing device that suppresses the behavior of the timing chain spanned between the plurality of cam sprockets housed in the chain cover,
A biasing means for biasing the timing chain between the cam sprockets so as to follow the displacement behavior of the timing chain in the slack direction when slack occurs;
A timing chain characterized by comprising damping means for damping the timing chain displacement behavior with oil collected in the chain cover when tension occurs in the timing chain between the cam sprockets. Behavior suppression device. In the timing chain behavior suppressing device according to claim 1,
A timing chain side plate that is in sliding contact with the timing chain;
An anti-timing chain side plate fixed to the anti-timing chain side of the timing chain side plate and having an axis that rotatably supports one side end of the timing chain side plate;
The timing chain behavior suppressing device, wherein the timing chain side plate and the anti-timing chain side plate are configured such that surfaces facing each other are in contact with each other in the direction of displacement behavior of the timing chain. In the timing chain behavior suppressing device according to claim 2,
The timing chain side plate and the anti-timing chain side plate are curved with substantially the same curvature that is convex to the timing chain side,
Between the timing chain side plate and the counter-timing chain side plate, a space for storing oil is formed when the surfaces facing each other are in contact with each other.
An apparatus for suppressing the behavior of a timing chain, characterized in that biasing means is accommodated in the space portion. In the timing chain behavior suppressing device according to claim 2 or 3,
A timing chain behavior suppressing device, wherein the timing chain side plate and the counter-timing chain side plate are provided with recesses that substantially overlap each other when the mutually facing surfaces contact each other.

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