JP2008075624A - Timing confirming mechanism for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition capable of maintaining a function as a member for confirming a relative positional relationship between a rotation phase of a crank sprocket and a rotation phase of a cam sprocket as a function of a mass damper even while covering a mass damper attached to one end of a crankshaft by cover, with respect to an internal combustion engine not using a belt drive system for auxiliary machine driving. <P>SOLUTION: The damper cover 7 covering the mass damper 6 is attached to an outer face of a chain cover 5. An opening 75 is formed in an upper end of the damper cover 7 to allow visual confirmation of a timing mark 61 formed on the mass damper 6 from the exterior. A drain outlet 76 is formed in a lower end of the drain cover 7 to provide easy discharge of rainwater or the like intruding into the damper cover 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a timing confirmation mechanism for confirming a rotational phase position of a camshaft with respect to a crankshaft in an internal combustion engine represented by an automobile engine, for example. In particular, the present invention relates to a measure for enhancing the practicality of a timing confirmation mechanism in an internal combustion engine that does not include a belt for driving accessories.

  In general, in a four-cycle engine (internal combustion engine) applied for automobiles or the like, a timing chain is stretched between a crank sprocket attached to the crankshaft and a cam sprocket attached to the camshaft. Thereby, the rotational force of the crankshaft accompanying the drive of the engine is transmitted to the camshaft via the timing chain, and the valve train of the engine is driven.

  In addition, the rotation phase of the crank sprocket (synonymous with the rotation phase of the crankshaft) and the rotation phase of the cam sprocket (cam) so that each valve of the valve train opens and closes at an appropriate timing during the intake stroke and exhaust stroke of the engine. It is necessary to have a predetermined relative positional relationship with the same meaning as the rotational phase of the shaft. For example, when the piston of a cylinder is at a position immediately before reaching exhaust top dead center (predetermined advance angle position), it is suitable for the rotation phase of the crank sprocket so that the opening operation of the intake valve of that cylinder is started It is necessary to obtain the rotational phase of the cam sprocket.

  In order to realize this, as disclosed in, for example, Patent Document 1 below, a timing mark is imprinted on the surface of each sprocket, and the timing is set in a state where the imprint of each sprocket is at a predetermined rotational phase position. I try to wind the chain. Specifically, for example, a timing mark corresponding to each sprocket is also formed on the timing chain, and the timing chain is aligned so that the timing mark position of each sprocket matches the timing mark position of the timing chain. The rotational phase of the crank sprocket and the rotational phase of the cam sprocket are obtained as having a predetermined relative positional relationship.

  By the way, when the engine is used for a long period of time, the relative positional relationship between the rotation phase of the crank sprocket and the rotation phase of the cam sprocket is caused by the elongation of the chain or the decrease of the biasing force of the tensioner. May end up. Hereinafter, this is referred to as “timing deviation”. If this timing shift occurs, the valve opening / closing timing of the valve operating system cannot be obtained properly, leading to a decrease in engine performance.

  For this reason, it is desirable to periodically inspect whether or not the above timing deviation has occurred, but in general, the timing chain and each sprocket are covered with a chain cover, and there is lubricating oil inside. is doing. Therefore, removing the chain cover every time it is inspected whether or not the above timing deviation has occurred, not only is the work complicated, but if the lubricating oil leaks during this operation, the inspection is completed. You will have to replenish the lubricating oil later.

  In order to solve this problem, conventionally, a crank pulley for driving auxiliary machinery disposed outside the chain cover has been used. This crank pulley has a belt spanned between auxiliary pulleys such as a water pump pulley, an air conditioner compressor pulley, and an alternator pulley, and transmits the rotational force of the crankshaft to each auxiliary pulley via the belt. It drives the auxiliary machinery.

  A timing mark is imprinted on the surface of the crank pulley. The timing mark of the crank pulley is formed at the same phase position as the timing mark stamped on the crank sprocket or at a position having a predetermined phase angle. On the other hand, a mark (reference mark) for performing alignment with the timing mark stamped on the crank pulley is stamped on the outer surface of the chain cover.

For this reason, when the crank pulley timing mark and the chain cover reference mark are aligned, the crank sprocket is always in a certain rotational phase position, and if the operating position of each valve in this state is confirmed, etc. It can be confirmed whether or not a deviation occurs in the above timing. In other words, since the relative positional relationship between the rotational phase of the crank sprocket and the rotational phase of the cam sprocket can be confirmed via the crank pulley, the above timing deviation can be confirmed without removing the chain cover. Good.
JP 2004-285975 A

  By the way, the inventor of the present invention has considered the driving of the auxiliary machines without using the rotational force of the crankshaft. For example, in a so-called hybrid vehicle that is equipped with an engine and an electric motor for traveling and travels with one or both of these driving forces, the water pump or the air-conditioning compressor is electrically operated, or the motor generator is By providing it, an alternator can be made unnecessary, so that a belt drive system for driving auxiliary machinery (a system constituted by the crank pulley, the belt, etc.) becomes unnecessary.

  Further, the crank pulley has a function of damping the crankshaft in addition to the function of transmitting the rotational force of the crankshaft to the auxiliary machinery. In other words, it functions as a weight attached to the tip of the crankshaft, thereby suppressing vibration during crankshaft rotation.

  For this reason, if the belt drive system for driving the accessories is not required, the crank pulley may be provided with a crankshaft damping function. In other words, the crank pulley only needs to have a function as a weight member that is rotated and integrated with the crankshaft (a function as a so-called mass damper). That is, it becomes a member which does not need to wind a belt.

  In such a configuration, only the member that has been used as a crank pulley so far (hereinafter referred to as a mass damper) is rotated with the crankshaft on the outside of the chain cover. In such a situation, the engine does not look good, and another member may come into contact with the rotating mass damper to adversely affect the rotation of the crankshaft. Therefore, the inventors of the present invention have considered that a damper cover for covering the mass damper is attached to the chain cover.

  However, this mass damper, as described above, functions as a member (a member for confirming the relative positional relationship between the rotational phase of the crank sprocket and the rotational phase of the cam sprocket) for inspecting the timing deviation of the valve operating system. It is also necessary to secure it. Therefore, the timing mark is also engraved on the surface of the mass damper as in the case of the crank pulley. However, if the entire damper is covered by the damper cover, the timing mark is confirmed from the outside. It becomes impossible.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a mass damper attached to one end of a crankshaft for an internal combustion engine that has eliminated a belt drive system for driving accessories. An object of the present invention is to provide a configuration capable of maintaining the function as a member for confirming the relative positional relationship between the rotational phase of the crank sprocket and the rotational phase of the cam sprocket as a function of the mass damper while being covered with a cover.

-Solving principle-
The solution principle of the present invention devised to achieve the above object is that the cover member is configured to cover the mass damper with a cover member in accordance with the elimination of the belt drive system for driving auxiliary machinery. By partially providing an opening in the structure, the timing mark provided on the mass damper can be confirmed from the outside.

-Solution-
Specifically, the present invention relates to a relative positional relationship between a rotational phase of a driving side rotating body (for example, a crank sprocket) attached to a crankshaft and a rotational phase of a driven side rotating body (for example, a cam sprocket) attached to a camshaft. In order to confirm whether or not there is a deviation, the crankshaft is integrally attached to the crankshaft at a position outside the first cover member (for example, a chain cover) that covers the drive side rotating body, and a timing mark is formed on the surface. A timing confirmation mechanism provided with a weight member (the mass damper) is assumed. A second cover member disposed to cover the weight member is attached to the first cover member with respect to the timing confirmation mechanism. The second cover member is formed with an opening that allows the timing mark to face when the weight member is at a predetermined rotational position so that the timing mark can be seen from the outside.

  Due to this specific matter, when the second cover member is provided in consideration of the appearance of the weight member existing outside the first cover member, an opening is formed in the second cover member. By forming, when the weight member is at a predetermined rotational position, the timing mark can be visually observed from this opening, and it becomes possible to confirm the deviation of the rotational phase between the driving side rotating body and the driven side rotating body. . That is, by making it possible to confirm the relative positional relationship between the rotational phase of the crankshaft and the rotational phase of the camshaft (or the rotational phase of the crank sprocket and the rotational phase of the cam sprocket) via the weight member, the appearance of the internal combustion engine is improved. It is possible to check the timing shift without removing the first cover member while securing the above.

  In addition, as a specific configuration of the second cover member, a drain discharge opening is formed at a lower end portion thereof. According to this, even if water (for example, rainwater) enters the inside of the second cover member by forming the timing mark confirmation opening, it can be easily discharged from the drain discharge opening. Moreover, since it can discharge | emit even when a foreign material (pebbles etc.) enters, it does not obstruct rotation of a weight member.

  In addition, as a configuration for enabling the drain discharge opening to be abolished, a configuration in which a sealing member for sealing the opening for enabling the timing mark of the weight member to be visually attached is detachably attached to the second cover member. It is done.

  This blocking member is removed from the second cover member only when the rotational phase deviation between the driving side rotating body and the driven side rotating body is confirmed, and otherwise the opening is blocked. For this reason, the possibility that foreign matters such as rainwater and pebbles enter the inside of the second cover member is reduced, and a configuration that does not necessarily require a drain discharge opening can be realized.

  Further, as a more specific configuration of the timing confirmation mechanism, the driving side rotating body is a crank sprocket attached to one end portion of the crankshaft, while the driven side rotating body is a cam sprocket attached to one end portion of the camshaft. It is. And it is set as the structure which spanned the timing chain over these sprockets.

  According to the present invention, in contrast to the configuration in which the weight member is covered with the cover member (second cover member) in accordance with the elimination of the belt drive system for driving auxiliary machinery, the cover member is partially opened. By providing it, the timing mark provided on the weight member can be confirmed from the outside. For this reason, the relative positional relationship between the rotational phase of the crankshaft and the rotational phase of the camshaft can be confirmed via the weight member, so that the timing deviation can be confirmed without removing the first cover member. However, the appearance of the internal combustion engine can be improved, and the practicality of the timing confirmation mechanism in the internal combustion engine that does not include a belt for driving accessories can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, the case where the present invention is applied to an engine (internal combustion engine) that is mounted on a hybrid vehicle that is mounted with an engine and an electric motor for traveling and that travels with one or both of these driving forces will be described. To do.

(First embodiment)
-Camshaft drive mechanism-
FIG. 1 is an exploded perspective view of a camshaft drive mechanism portion (mechanism portion for transmitting the rotational force of the crankshaft 1 to the camshafts 2 and 3) in the DOHC type in-line engine according to the present embodiment. The cylinder head, head cover, etc. are omitted.

  As shown in FIG. 1, an intake side camshaft 2 and an exhaust side camshaft 3 are arranged in parallel to each other in the valve train disposed in the upper part of the engine.

  On the other hand, a crankshaft 1 serving as an engine output shaft is disposed extending in the horizontal direction below the cylinder block of the engine. Pistons (both not shown) are connected to the crankshaft 1 at a plurality of locations (four locations in the case of a 4-cylinder engine) via connecting rods. That is, the explosive force of the air-fuel mixture in the combustion stroke of the engine is transmitted to the crankshaft 1 through the piston and the connecting rod, and the rotational force of the crankshaft 1 is taken out as the driving force of the engine.

  A crank sprocket (drive-side rotator) 11 is integrally attached to one end of the crankshaft 1 (one end opposite to the side where a transmission (not shown) is provided). An intake side cam sprocket (driven rotor) 21 is provided at one end of the intake side camshaft 2 above the position where the crank sprocket 11 is disposed, and an exhaust side cam sprocket is provided at one end of the exhaust side camshaft 3. The (driven-side rotator) 31 is attached integrally with each other.

  The timing chain 4 is wound around the sprockets 11, 21, 31, and the rotational force of the crankshaft 1 accompanying the driving of the engine is transmitted to the cam sprockets 21, 31 via the timing chain 4. The camshafts 2 and 3 are rotated at a rotational speed that is ½ of the rotational speed of the crankshaft 1. As a result, the intake valves and the exhaust valves (not shown) are opened and closed at a predetermined opening / closing timing (valve timing) by the action of the cam lobes 22 and 32 formed on the camshafts 2 and 3.

  An NE rotor (timing rotor) 12 for detecting the engine speed is integrally attached to one end of the crankshaft 1 outside the position where the crank sprocket 11 is disposed.

  The camshaft drive mechanism portion configured in this way is covered with a chain cover (first cover member) 5. The chain cover 5 is a plate made of an aluminum alloy, and a flange portion 51 formed on the outer peripheral edge thereof is bolted to the cylinder block and the cylinder head, so that the space between the cylinder block and the cylinder head is reduced. The chain arrangement space is formed. The constituent material of the chain cover 5 is not limited to aluminum alloy.

  In FIG. 1, 41 is a chain tensioner device that adjusts the tension of the timing chain 4, 42 is a chain vibration damper that guides the stretched portion of the timing chain 4, and 23 is a VVT unit.

  As shown in FIG. 2 (a longitudinal sectional view of the crank sprocket 11 and its peripheral portion), one end of the crankshaft 1 protrudes outward from the chain cover 5, and the crankshaft 1 A mass damper 6 made of a metal disk is attached to the tip portion, which is a protruding portion, by rotating means such as a bolt. Hereinafter, the mass damper 6 will be described.

-Mass damper 6
The engine according to this embodiment is an engine mounted on a hybrid vehicle as described above. For this reason, the water pump and the compressor for the air conditioner are electrically driven, and the alternator is not required because the motor generator is provided. Therefore, a belt drive system for driving auxiliary machines, which is necessary in a general automobile having only an internal combustion engine as a drive source, is not required.

  For this reason, in this hybrid vehicle, the function of transmitting the rotational force of the crankshaft 1 to the accessories is unnecessary among the functions of the conventional crank pulley (the pulley on which the belt for driving the accessories) is wound. . That is, although it becomes a member which does not need to wind a belt, the damping function with respect to the crankshaft 1 is required. That is, it functions as a weight attached to the tip of the crankshaft 1 so as to suppress vibration during crankshaft rotation. For this reason, this member is the mass damper 6 as a weight member which is integrally rotated with the crankshaft 1.

  As described above, in the engine according to the present embodiment, the mass damper 6 is disposed as a member that has been used as a crank pulley so far outside the chain cover 5, and the mass damper 6 rotates together with the crankshaft 1. It has become.

  Further, the function of the mass damper 6 is a member for inspecting the timing deviation of the valve system (a member for confirming the relative positional relationship between the rotational phase of the crank sprocket 11 and the rotational phase of the cam sprockets 21 and 31). ) Function must be secured. Therefore, a timing mark 61 is engraved on a part of the outer edge portion on the surface of the mass damper 6. The timing mark 61 of the mass damper 6 is formed at the same phase position as the timing mark (not shown) imprinted on the crank sprocket 11 or at a position having a predetermined phase angle. On the other hand, as shown in FIG. 3 (a view of the periphery of the position where the mass damper 6 is disposed as viewed from the direction along the axis of the crankshaft 1), a timing mark 61 stamped on the mass damper 6 is formed on the outer surface of the chain cover 5. A mark (reference mark) 53 for performing alignment with is engraved. Specifically, the mark member 52 protrudes from the outer surface of the chain cover 5 above the position where the mass damper 6 is disposed, and three reference marks 53 are formed on the front end surface (side end surface) of the mark member 52. ing.

  Therefore, when the timing mark 61 and the reference mark 53 of the mass damper 6 are aligned as shown in FIG. 3, the crank sprocket 11 is always in a certain rotational phase position, and the operating position of each valve in this state. It is possible to confirm whether or not a deviation occurs in the above timing. That is, the relative positional relationship between the rotational phase of the crank sprocket 11 and the rotational phase of the cam sprockets 21, 31 can be confirmed via the mass damper 6, so that the timing shift can be achieved without removing the chain cover 5. The configuration can be confirmed.

−Damper cover−
As one of the characteristics of this embodiment, a damper cover (second cover member) 7 for covering the mass damper 6 is attached to the chain cover 5. Hereinafter, the damper cover 7 will be described.

  The damper cover 7 has a flat cover portion 71 formed larger than the shape (circular shape) in a side view of the mass damper 6, and a wall extending from the outer edge of the cover portion 71 toward the surface of the chain cover 5. 72 and a flange portion 73 that extends slightly outward from the tip of the wall portion 72. The flange portion 73 is integrally formed with mounting flanges 74, 74 extending on both sides in the horizontal direction. A bolt hole 74a (see FIG. 1) is formed in the mounting flange 74, while a similar bolt hole 54 is formed in the chain cover 5 corresponding to the bolt hole 74a. For this reason, by screwing the bolt B from the outside in a state where the bolt hole 74 a of the mounting flange 74 of the damper cover 7 and the bolt hole 54 of the chain cover 5 are aligned, the damper cover 7 covers the mass damper 6. The chain cover 5 is attached. That is, the mass damper 6 is covered with the damper cover 7.

  As a feature of the present embodiment, the damper cover 7 is formed with an opening 75 for making the timing mark 61 of the mass damper 6 visible from the outside. The opening 75 is formed by partially notching the cover portion 71, the wall portion 72, and the flange portion 73 at the upper end position of the damper cover 7. More specifically, as shown in FIG. 3, the shape of the opening 75 is set to a substantially trapezoidal shape in which the opening width decreases downward.

  Therefore, when the timing mark 61 is at the upper end position as shown in FIG. 3 as the rotational position of the mass damper 6, the timing mark 61 can be visually observed from the outside due to the presence of the opening 75. In addition, since most of the mass damper 6 is covered by the damper cover 7, the appearance of the engine is ensured well.

  Furthermore, a drain discharge opening 76 formed of a rectangular opening is formed at the lower end portion of the wall portion 72 in the damper cover 7 of the present embodiment. By forming such a drain discharge opening 76, even if water (for example, rainwater) enters the inside of the damper cover 7, it can be easily discharged from the drain discharge opening 76. Moreover, since it can discharge | emit even when a foreign material (pebbles etc.) enters, it will not interfere with rotation of the mass damper 6. FIG.

-Timing check operation-
Next, an operation for confirming whether or not there is a deviation in the relative positional relationship between the rotational phase of the crank sprocket 11 and the rotational phase of the cam sprockets 21 and 31 will be described.

  In this operation, first, the rotation position of the mass damper 6 is set to a position where the timing mark 61 becomes the upper end position as shown in FIG. 3, and the timing mark 61 and the three reference marks formed on the mark member 52 are set. The reference mark 53 at the center of 53 is aligned. As described above, the timing mark 61 of the mass damper 6 is formed at the same phase position as the timing mark imprinted on the crank sprocket 11 or at a position having a predetermined phase angle. In this state, the crank sprocket 11 Will always be at a certain rotational phase position.

  Then, by confirming the operation position of each valve in this state, it is confirmed whether or not a deviation occurs in the timing. When it is confirmed that the timing is shifted by this operation, the chain tensioner device 41 is adjusted and the tension of the timing chain 4 is changed. Will be implemented.

  As described above, in the present embodiment, the configuration in which the relative positional relationship between the rotational phase of the crankshaft 1 and the rotational phase of the camshafts 2 and 3 can be confirmed without removing the chain cover 5 and the mass damper 6 are covered. It is possible to achieve a good appearance of the engine by hiding it, and to improve the practicality of the timing confirmation mechanism in an engine that does not have a belt drive system for driving accessories (so-called beltless engine). it can.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the present embodiment, the configuration of the damper cover 7 is different from that of the first embodiment described above, and other configurations are the same as those of the first embodiment. Accordingly, only differences from the first embodiment will be described here.

  FIG. 4 is a longitudinal sectional view of the crank sprocket 11 and its peripheral part in the present embodiment (a figure corresponding to FIG. 2 above), and FIG. 5 shows the position around the position where the mass damper 6 is disposed from the direction along the axis of the crankshaft 1. FIG. 4 is a view (corresponding to FIG. 3).

  As shown in these drawings, the timing mark confirmation opening 75 ′ in the damper cover 7 of the present embodiment is formed by a circular opening formed in the cover portion 71 of the damper cover 7. The opening 75 ′ is normally sealed with a bolt (blocking member) 77 (see FIG. 4), and the timing check operation (the rotation phase of the crank sprocket 11 and the rotation phase of the cam sprockets 21, 31) When performing an operation for confirming whether or not the relative positional relationship is deviated), the bolt 77 is removed and the opening 75 ′ is opened (see FIG. 5). As a configuration for mounting the bolt 77, a nut 78 is attached to a position corresponding to the opening 75 ′ on the inner surface of the damper cover 7 by means of welding or the like. The bolt 77 is attached to the nut 78 with the damper cover. The opening 75 ′ is sealed by screwing in from the outside of 7.

  In addition, since the opening 75 ′ is normally blocked by the bolt 77 as described above, there is a low possibility that foreign matter such as rainwater and pebbles enter the inside of the damper cover 7. The drain discharge opening 76 is not formed. Other configurations are the same as those of the first embodiment described above.

  Also in this embodiment, it is possible to confirm the relative positional relationship between the rotational phase of the crankshaft 1 and the rotational phase of the camshafts 2 and 3 without removing the chain cover 5 (only by removing the bolt 77). . In addition, the mass appearance of the engine can be ensured by covering the mass damper 6 with the damper cover 7. For this reason, it is possible to improve the practicality of the timing confirmation mechanism in an engine that does not include a belt drive system for driving accessories.

  In the present embodiment, the drain discharge opening 76 is not formed in the damper cover 7. However, the present invention is not limited to this, and the drain discharge opening 76 may be formed.

(Other embodiments)
Each embodiment described above has described the case where the present invention is applied to a hybrid vehicle. The present invention is not limited to this, and can be applied to any vehicle that does not require a belt drive system for driving auxiliary machinery without being limited to a hybrid vehicle. The engine to which the present invention is applicable is not limited to a DOHC type in-line engine, but may be an engine having an OHC type valve mechanism, a V type engine, or the like.

  Further, the timing mark 61 is not limited to the stamped one but may be a protrusion drawn on the surface of the mass damper 6 or a protrusion formed on the surface of the mass damper 6.

It is a disassembled perspective view of the camshaft drive mechanism part of the engine which concerns on 1st Embodiment. It is a longitudinal cross-sectional view of the crank sprocket and its peripheral part in 1st Embodiment. It is the figure which looked at the arrangement position vicinity of the mass damper in 1st Embodiment from the direction in alignment with the axis line of a crankshaft. It is a longitudinal cross-sectional view of the crank sprocket and its peripheral part in 2nd Embodiment. It is the figure which looked at the arrangement position of the mass damper in 2nd Embodiment from the direction in alignment with the axis line of a crankshaft.

Explanation of symbols

1 Crankshaft 11 Crank sprocket (Rotating body on the drive side)
2 Intake side camshaft 3 Exhaust side camshafts 21, 31 Cam sprocket (driven rotor)
5 Chain cover (first cover member)
6 Mass damper (weight member)
61 Timing mark 7 Damper cover (second cover member)
75, 75a Opening 76 Drain discharge opening 77 Bolt (blocking member)

Claims (4)

In order to check whether or not there is a deviation in the relative positional relationship between the rotational phase of the driving side rotating body attached to the crankshaft and the rotational phase of the driven side rotating body attached to the camshaft, the driving side rotating body A timing confirmation mechanism comprising a weight member that is integrally attached to the crankshaft at a position outside the first cover member that covers the weight and has a timing mark formed on the surface thereof,
A second cover member disposed so as to cover the weight member is attached to the first cover member. When the weight member is in a predetermined rotational position, the second cover member is attached to the first cover member. A timing confirmation mechanism for an internal combustion engine, characterized in that an opening is formed to allow the timing mark to face and to be viewed from the outside of the timing mark. In the timing confirmation mechanism according to claim 1,
A timing confirmation mechanism for an internal combustion engine, wherein a drain discharge opening is formed in a lower end portion of the second cover member. In the timing confirmation mechanism according to claim 1 or 2,
A timing confirmation mechanism for an internal combustion engine, wherein a sealing member for sealing an opening for allowing a timing mark of a weight member to be visually recognized is detachably attached to the second cover member. In the internal combustion engine timing confirmation mechanism according to claim 1, 2, or 3,
The driving side rotating body is a crank sprocket attached to one end portion of the crankshaft, while the driven side rotating body is a cam sprocket attached to one end portion of the camshaft, and a timing chain is stretched over these sprockets. A timing confirmation mechanism for an internal combustion engine, characterized in that it is configured.

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