JP2006064140A - Idler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an idler which can stably guide a timing chain, and also can reduce the noise generated in guiding the timing chain. <P>SOLUTION: The idler 51 comprises an idler shaft 52 which elongates along an axis 101 elongating in the required direction and is fixed to a cylinder block 45, an idler sprocket wheel 54, which guides the primary timing chain wound thereon by turning about the axis 101, a spring 71 which is provided so as to come into contact with the idler sprocket wheel 54 in order to restrict the movement of the idler sprocket wheel 54 in the required direction by energizing the idler sprocket wheel 54 in the required direction, and a lubricating oil supply passage 56 for supplying lubricating oil to the position where the idler sprocket wheel 54 is in contact with the spring 71. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates generally to an idler that regulates the trajectory of an engine timing chain, and more particularly to an idler used in a V-type multi-cylinder engine.

  Japanese Utility Model Laid-Open No. 7-35707 discloses a valve for an internal combustion engine for preventing the occurrence of a hitting sound between the teeth of meshing gears and miniaturizing the device while ensuring sufficient spring force. A timing control device is disclosed (Patent Document 1). The valve timing control device disclosed in Patent Document 1 includes a sleeve, a sprocket disposed on the outer periphery of the sleeve via a cylindrical gear, and a disc spring that biases the sprocket in the axial direction of the sleeve. The sleeve and the cylindrical gear and the cylindrical gear of the sprocket are rotatably connected by meshing the helical teeth.

The sleeve is fixed to a camshaft that rotates by the driving force transmitted from the crankshaft of the engine and rotates to open and close the valve. When changing the valve timing, the cylindrical gear is moved in the axial direction of the sleeve by hydraulic pressure, and the sprocket and the sleeve are relatively rotated. When the valve timing is not controlled, the sleeve and the sprocket are rotating together with the camshaft at the same rotational speed.
Japanese Utility Model Publication No. 7-35707

  Some engines employ a chain drive system to transmit drive force between the crankshaft and camshaft. In such an engine, a timing chain is stretched between these shafts, but depending on the structure of the engine, an idler (playwheel) for guiding the timing chain may be provided to regulate the timing chain track.

  However, the spring force of the valve spring acts on the camshaft while changing its magnitude, and the tension applied to the timing chain is constantly changing. As a result, the timing chain rotates at a high speed while undulating between the crankshaft and the camshaft. When trying to guide such a timing chain using an idler, a large fluctuating load is applied from the timing chain to the idler. For this reason, the problem that a loud noise generate | occur | produces with an idler arises.

  Accordingly, an object of the present invention is to solve the above-described problems, and to provide an idler that can stably guide a timing chain and reduce noise generated during guidance.

  The idler according to the present invention is an idler that regulates the trajectory of the timing chain of the engine. The idler extends along an axis extending in a predetermined direction (hereinafter also referred to as a thrust direction), and a shaft member fixed to the engine body and a timing chain are hung, and the idler rotates around the above-described axis. A sprocket that guides the timing chain, a spring member that is provided in contact with the sprocket and that urges the sprocket in the predetermined direction to restrict movement of the sprocket in the predetermined direction, and the sprocket and the spring A lubricating oil supply mechanism that supplies lubricating oil is provided at a position in contact with the member.

  The engine timing chain refers to a chain that transmits the driving force output from the engine to the camshaft. The engine body refers to a part that constitutes the engine, such as a cylinder block and a cylinder head, and does not rotate or reciprocate during operation of the engine.

  According to the idler configured as described above, by providing the spring member, an elastic force can be applied to the rotating sprocket so that the gap in the thrust direction is always substantially zero. Thereby, it is possible to prevent the sprocket from vibrating in the thrust direction due to the fluctuating load received from the timing chain. Further, the lubricating oil is supplied between the spring member and the rotating sprocket by the lubricating oil supply mechanism. For this reason, although the sprocket rotates while contacting the spring member, the sprocket can be smoothly rotated. For these reasons, according to the present invention, it is possible to stably guide the timing chain and reduce the noise generated by the idler.

  Preferably, the spring member is provided with a detent mechanism for the shaft member. According to the idler configured as described above, the spring member can be prevented from being pulled with respect to the sprocket and rotating with respect to the shaft member when the sprocket is rotated. Thereby, it becomes unnecessary to supply lubricating oil between both, and the burden with respect to lubrication can be reduced.

  The engine is a V-type multi-cylinder engine. The idler is located between the banks of the engine. Idler regulates the orbit of the timing chain spanned between the camshafts of both banks. In the idler configured in this way, the timing chain receives variable loads from both camshafts arranged in both banks, so noise generated by the idler becomes a particularly serious problem. For this reason, when the present invention is applied to a V-type multi-cylinder engine, the above-described effects can be obtained more effectively.

  As described above, according to the present invention, it is possible to provide an idler that can stably guide the timing chain and reduce the noise generated during the guidance.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing an engine using an idler according to an embodiment of the present invention. FIG. 2 is a perspective view showing a valve system of the engine in FIG. Referring to FIGS. 1 and 2, engine 10 is a V-type multi-cylinder engine including a left bank 11 and a right bank 12 arranged in a V shape.

  Each of the left bank 11 and the right bank 12 is provided with, for example, four cylinders, and each cylinder is loaded with a piston that reciprocates in the cylinder. The piston is connected to a crankshaft that is an output shaft of the engine 10 by a connecting rod. A crankshaft sprocket 29 is attached to the end of the crankshaft. The crankshaft sprocket 29 is attached to a side surface of a cylinder block that constitutes the engine 10.

  The left bank 11 is provided with an intake camshaft 37 and an exhaust camshaft 36. In the right bank 12, an intake camshaft 38 and an exhaust camshaft 39 are disposed. In these camshafts, a plurality of cams having appropriate contour curves are formed side by side in the axial direction of the camshaft. As the cam shaft rotates, the cam opens and closes intake and exhaust valves provided in each cylinder.

  A sprocket 30 is provided at the end of the exhaust camshaft 36. At the end of the exhaust camshaft 36, there is further provided a variable valve timing mechanism 16 that rotates the exhaust camshaft 36 relative to the sprocket 30 by hydraulic pressure to change the cam timing of the exhaust camshaft 36.

  Similarly, a small-diameter sprocket 32, a large-diameter sprocket 31, and a variable valve timing mechanism 17 are provided side by side in the axial direction of the intake camshaft 37 at the end of the intake camshaft 37. A small-diameter sprocket 34, a large-diameter sprocket 33, and a variable valve timing mechanism 18 are provided at the end of the intake camshaft 38 side by side in the axial direction of the intake camshaft 38. A sprocket 35 and a variable valve timing mechanism 19 are provided at the end of the exhaust camshaft 39 side by side in the axial direction of the exhaust camshaft 39.

  The sprocket 30, the small-diameter sprocket 32, the large-diameter sprocket 31, the small-diameter sprocket 34, the large-diameter sprocket 33, and the sprocket 35 are located on the side surface of the camshaft housing and provided on each camshaft. The camshaft housing is a component fastened to the cylinder head constituting the engine 10 from the top surface side.

  A primary timing chain 24 is wound around the crankshaft sprocket 29, the large diameter sprocket 31 and the large diameter sprocket 33. The primary timing chain 24 is spanned so that these three sprockets are located inside the track of the primary timing chain 24. The primary timing chain 24 is guided between the crankshaft sprocket 29 and the large-diameter sprocket 31 by a long chain damper 26. The primary timing chain 24 is guided between the crankshaft sprocket 29 and the large-diameter sprocket 33 by a long chain slipper 25 having a chain tensioner mechanism.

  An idler 51 is provided between the large-diameter sprocket 31 and the large-diameter sprocket 33 so as to be positioned inside a triangle connecting the large-diameter sprocket 31, the large-diameter sprocket 33, and the crankshaft sprocket 29. The idler 51 includes an idler sprocket 54 that is rotatably provided. A primary timing chain 24 extending between the large-diameter sprocket 31 and the large-diameter sprocket 33 is hung on the idler sprocket 54. The primary timing chain 24 is hung on the idler sprocket 54 so that the idler 51 is located outside the track of the primary timing chain 24.

  The idler 51 adjusts the path of the primary timing chain 24 along a path along the V shape of the engine 10 so that the amount of winding of the primary timing chain 24 around the large-diameter sprocket 31 and the large-diameter sprocket 33 increases. Has been adjusted. The primary timing chain 24 is guided between the large-diameter sprocket 31 and the large-diameter sprocket 33 and the idler sprocket 54 by a chain damper 27 that is shorter than the chain damper 26 and the chain slipper 25.

  A secondary timing chain 21 is stretched between the small-diameter sprocket 32 and the sprocket 30. A secondary timing chain 22 is stretched between the small-diameter sprocket 34 and the sprocket 35. With the configuration described above, the driving force output from the crankshaft is first transmitted to the intake camshaft 37 and the intake camshaft 38 via the primary timing chain 24, and further via the secondary timing chains 21 and 22. , To the exhaust camshafts 36 and 39.

  3 is a cross-sectional view of the engine along the line III-III in FIG. Referring to FIG. 3, in addition to idler sprocket 54, idler 51 further includes idler shaft 52 having an outer peripheral surface 52a with shaft 101 as the central axis, and spring 71 fitted on outer peripheral surface 52a. .

  The idler shaft 52 is fastened to the side surface 45c of the cylinder block 45 constituting the engine 10 in FIG. The idler shaft 52 protrudes from the side surface 45c and extends along the shaft 101. The idler shaft 52 has a flange portion 58 that extends from the outer peripheral surface 52a in the radial direction at the extended tip. A hexagonal hole 53 is formed on the end surface of the idler shaft 52. The hexagonal hole 53 is used as a hole into which a hexagonal wrench is inserted when the idler shaft 52 is fastened to the cylinder block 45.

  The idler sprocket 54 is fitted around the outer peripheral surface 52 a so as to be aligned with the spring 71 in the direction of the axis 101. The spring 71 is positioned between the idler sprocket 54 and the flange portion 58, and the idler sprocket 54 is positioned between the spring 71 and the cylinder block 45. The spring 71 is provided in contact with the idler sprocket 54.

  The idler sprocket 54 has an inner peripheral surface 54d that faces the outer peripheral surface 52a. On the inner peripheral surface 54d, an idler shaft 52 and a ring-shaped bearing member 55 made of a material that is difficult to seize are fixed. With such a configuration, the idler sprocket 54 is rotatably provided via the bearing member 55. That is, the idler sprocket 54 rotates relative to the stationary idler shaft 52 with the shaft 101 as the central axis.

  The idler shaft 52 is formed with a lubricating oil supply passage 56 that extends from the position facing the side surface 45c of the cylinder block 45 toward the outer peripheral surface 52a and further extends in a belt shape in the circumferential direction of the outer peripheral surface 52a. The cylinder block 45 is formed with a lubricating oil supply path 46 that communicates from the main gallery in the cylinder block 45 to the lubricating oil supply path 56. Lubricating oil flowing through the main gallery passes through the lubricating oil supply passages 46 and 56 in order, and is supplied to the contact surface between the bearing member 55 and the idler shaft 52, and then further contacts with the spring 71 and the idler sprocket 54, and It is supplied to the contact surface between the side surface 45 c of the cylinder block 45 and the idler sprocket 54.

  FIG. 4 is a perspective view showing the spring in FIG. Referring to FIGS. 3 and 4, the alternate long and short dash line in FIG. 4 represents axis 101 in FIG. 3. The spring 71 includes a base portion 72 that extends in a ring shape, and an elastic portion 73 and a rotation stop portion 74 that are formed to extend from both ends of the base portion 72 in the direction of the shaft 101 in the radial direction. The elastic portions 73 are formed at four locations at approximately 90 ° intervals in the circumferential direction of the base portion 72. The rotation stoppers 74 are located between the adjacent elastic portions 73 and are formed at two locations in the circumferential direction of the base portion 72 at approximately 180 ° intervals.

  The elastic portion 73 is formed such that a tip extending from one end of the base portion 72 is separated from the idler sprocket 54 as the distance from the base portion 72 increases. The spring 71 is provided so that the elastic portion 73 bends in the direction of the shaft 101 between the idler sprocket 54 and the flange portion 58 in a state of being fitted on the outer peripheral surface 52a. As a result, an elastic force that urges the idler sprocket 54 in the direction of the shaft 101 is generated. The idler sprocket 54 receives the elastic force of the spring 71 and rotates around the idler shaft 52 while being restricted from moving in the direction of the shaft 101. The force for urging the idler sprocket 54 is such that the gap between the idler sprocket 54 and the end face 45c of the cylinder block 45 can be maintained at substantially zero when the idler sprocket 54 rotates. It is set so small that it does not hinder the rotation of 54.

  FIG. 5 is an end view showing the idler shaft as viewed from the arrow V in FIG. With reference to FIGS. 3 to 5, the rotation stopper 74 is formed such that a tip extending from one end of the base 72 is further bent in the direction of the axis 101. On the other hand, in the idler shaft 52, groove portions 61 are formed at two positions approximately 180 ° apart from the periphery of the flange portion 58. In the state where the spring 71 is fitted on the outer peripheral surface 52 a, the tip of the anti-rotation portion 74 is fitted into the groove portion 61.

  With such a configuration, the spring 71 can be prevented from rotating with respect to the idler shaft 52 when the idler sprocket 54 rotates. Thereby, it is not necessary to extend the lubricating oil supply path 56 toward the flange portion 58 and supply the lubricating oil to the contact surface between the spring 71 and the idler shaft 52. Further, by reducing the sliding position between the spring 71 and other members, the deterioration of the spring 71 can be prevented and the reliability thereof can be improved.

  The idler 51 in the embodiment of the present invention is an idler that regulates the trajectory of the primary timing chain 24 as the timing chain of the engine 10. The idler 51 extends along a shaft 101 extending in a predetermined direction, and an idler shaft 52 as a shaft member fixed to a cylinder block 45 as an engine body and a primary timing chain 24 are hung on the shaft 101. The idler sprocket 54 as a sprocket that guides the primary timing chain 24 by rotating around the center, and the idler sprocket 54 is provided in contact with the idler sprocket 54, and by biasing the idler sprocket 54 in a predetermined direction, the predetermined direction Are provided with a spring 71 as a spring member for restricting the movement of the idler sprocket 54 and a lubricating oil supply path 56 as a lubricating oil supply mechanism for supplying the lubricating oil at a position where the idler sprocket 54 and the spring 71 are in contact with each other.

  In the present embodiment, the case where the idler shaft 52 is fixed to the cylinder block 45 has been described, but the present invention is not limited to this. The idler shaft 52 may be fixed to a cylinder head constituting the engine 10, or may be fixed to a cover member or a block member fastened to the cylinder block 45 or the cylinder head.

  According to the idler 51 in the embodiment of the present invention configured as described above, by providing the spring 71, the idler sprocket 54 can be prevented from vibrating in the direction of the shaft 101 during rotation. Accordingly, the idler sprocket 54 does not rotate while repeatedly colliding with the side surface 45c of the cylinder block 45 and the flange portion 58 of the idler shaft 52, and noise generated in the idler 51 can be reduced. Further, the contact surface between the spring 71 and the idler sprocket 54 is forcibly lubricated from the lubricating oil supply passage 56 as needed. Thereby, the sliding resistance between the spring 71 and the idler sprocket 54 and between the side surface 45c of the cylinder block 45 and the idler sprocket 54 can be reduced, and the idler sprocket 54 can be rotated smoothly.

  The idler 51 in the present embodiment is disposed between intake camshafts 37 and intake camshafts 38 provided in both banks of the V-type multi-cylinder engine, and a primary timing chain 24 hung between these camshafts. Regulating the orbit. However, the spring force of the valve spring acts on the cams formed on these camshafts, and the spring force changes with the rotation of the camshaft. For this reason, the intake camshaft 37 and the intake camshaft 38 rotate while receiving torque fluctuations in the rotation direction. In addition, the intake camshaft 37 and the intake camshaft 38 are connected to the exhaust camshafts 36 and 39 that rotate while receiving torque fluctuations similarly via the secondary timing chains 21 and 22.

  As a result, the primary timing chain 24 spanned between the intake camshaft 37 and the intake camshaft 38 transmits a driving force between the two while being greatly bent or stretched. Further, in the V-type multi-cylinder engine, it is difficult to provide a long guide such as the chain damper 26 or the chain slipper 25 between the idler sprocket 54, the large-diameter sprocket 31, and the large-diameter sprocket 33 due to its structure. It has become. This is also one of the causes that the primary timing chain 24 undulates greatly.

  When the idler 51 guides the primary timing chain 24 in such a state, an excessive fluctuating load is applied to the idler sprocket 54. However, in this embodiment, since the movement of the idler sprocket 54 in the direction of the shaft 101 is restricted, noise generated in the idler 51 can be effectively suppressed. For the reasons described above, the present invention is more effectively used for timing chain guidance performed between both banks of a V-type multi-cylinder engine.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a perspective view showing an engine using an idler according to an embodiment of the present invention. It is a perspective view which shows the valve system of the engine in FIG. It is sectional drawing of the engine along the III-III line in FIG. It is a perspective view which shows the spring in FIG. FIG. 4 is an end view showing an idler shaft as viewed from an arrow V in FIG. 3.

Explanation of symbols

  10 Engine, 24 Primary timing chain, 36, 39 Exhaust cam shaft, 37, 38 Intake cam shaft, 45 Cylinder block, 51 idler, 52 idler shaft, 54 Idler sprocket, 56 Lubricating oil supply path, 71 Spring, 74 Non-rotating part , 101 axis.

Claims (3)

An idler that regulates the trajectory of the engine timing chain,
A shaft member extending along an axis extending in a predetermined direction and fixed to the engine body;
A sprocket on which the timing chain is hung and guides the timing chain by rotating about the axis;
A spring member that is provided in contact with the sprocket and regulates movement of the sprocket in the predetermined direction by biasing the sprocket in the predetermined direction;
An idler comprising a lubricating oil supply mechanism that supplies lubricating oil at a position where the sprocket and the spring member are in contact with each other.   The idler according to claim 1, wherein the spring member is provided with a detent mechanism for the shaft member. The engine is a V-type multi-cylinder engine,
The idler according to claim 1 or 2, wherein the idler is provided between both banks of the engine and regulates a track of the timing chain spanned between camshafts of the banks.

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