JP4350861B2 - Valve timing control device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a valve timing control device for controlling the opening and closing timing of an intake valve and an exhaust valve of an internal combustion engine (hereinafter referred to as “engine”) according to operating conditions.
[0002]
[Prior art]
  Timing of opening and closing the intake and exhaust valves by rotating the assembly angle between a drive force transmission member such as a timing pulley that rotates synchronously with the crankshaft of the engine, a chain sprocket, and a camshaft having a drive cam on the outer periphery Conventionally, a valve timing control device for variably controlling the above has been devised, and this technique is disclosed in, for example, Japanese Patent Application Laid-Open No. 11-132013.
[0003]
  In the valve timing control device described in this publication, a vane member attached integrally to an end portion of a camshaft is accommodated in a housing member integral with a driving force transmission member, and an advance hydraulic pressure is contained in the housing member. Chambers and retarded hydraulic chambers are provided, and the vane member is rotated relative to the housing member by selectively sucking and discharging hydraulic pressure in each hydraulic chamber, thereby rotating the driving force transmitting member and the camshaft. The opening / closing timing of the intake valve and the exhaust valve is changed by changing the phase.
[0004]
  In such a so-called vane type valve timing control device, when the supply hydraulic pressure is low, such as when the engine speed is low, the pressure in the hydraulic chamber is defeated by the reaction force received from the intake valve or the exhaust valve, and the vane member It is known to be pushed and moved by reaction force. In order to cope with this, in the valve timing control device described in the above publication, a lock pin as a rotation restricting means for fixing the relative position between the vane member and the housing member is provided, and the vane member is provided by the lock pin. This prevents the push-back.
[0005]
[Problems to be solved by the invention]
  However, in the valve timing control device as described above that prevents the vane member from being pushed back by the lock pin, the peripheral area of the lock pin holding portion or the lock pin fitting portion of the vane member or the housing member is not necessary. This part is deformed with respect to the part, and the mass partly increases accordingly. In particular, in the case where the lock pin is provided on a part of the vane part of the vane member, the width of the part of the vane part has to be widened in order to allow the lock pin to be accommodated. Come. Therefore, there is a problem that the weight balance with respect to the rotation shaft is lost and smooth rotation is hindered. In particular, in such a valve timing control device, since the housing member and the vane member are always rotated at high speed by the crankshaft of the engine, the influence of weight imbalance is very large.
[0006]
  This problem not only hinders the smooth rotation of the valve timing control device, but also adversely affects the camshaft and bearings that support the valve timing control device, which may cause engine vibration and uneven wear of components. was there.
[0007]
  Currently, as a countermeasure for this problem, the weight increasing portion and the shaft pair on the outer peripheral surface of the housing member are used.NameHowever, this measure is not preferable from the viewpoint of reducing the size and weight of the engine because the outer shape of the housing member increases and the overall weight increases.
[0008]
  On the other hand, Japanese Patent Laid-Open No. 10-30411, which has already been issued, has a lightening portion on the partition wall of the housing member that separates the advance hydraulic chamber and the retard hydraulic chamber from the vane portion of the vane member. Thus, a technique of a valve timing control device that reduces the weight of the entire device and reduces the rotational moment is disclosed. Also, Japanese Patent Laid-Open Nos. 10-317920 and 11-101108 disclose the outer periphery of a housing member. It is also shown that a lightening portion is similarly provided in the partition wall corresponding portion of the surface to reduce the weight and the rotational moment.
[0009]
  These technologies are certainly effective in reducing the weight and reducing the rotational moment, but in fact, the housing members are already lightened to the limit and the wall thickness is considerably reduced. It is difficult to provide a punch. In other words, in any of the above-described techniques, if the thickness of the housing member is increased, the size of the partition wall is limited. If the size of the partition wall is increased, the rotation range of the vane member is increased. However, it is difficult to actually provide sufficient meat removal by becoming a neck.
[0010]
  By the way, as a measure for solving the problem of rotational imbalance associated with the addition of the lock pin, it is conceivable to use the technique described in the above-mentioned publication in which a thinned portion is provided in the housing member. In the case of removing and providing, the problem of the size of the partition wall becomes a bottleneck as described above, and it is difficult to realize it.
[0011]
  Therefore, the present invention has been made to solve such a problem, and without causing a design change to the vane member, the housing member, etc., the rotational imbalance associated with the provision of the rotation restricting means. An object of the present invention is to provide a valve timing control device for an internal combustion engine that can be eliminated.
[0012]
[Means for Solving the Problems]
  In order to achieve the above object, an invention according to claim 1 includes a driving force transmission member driven by a crankshaft of an internal combustion engine and a driving cam for operating an engine valve on an outer periphery, and the driving force transmission. A camshaft that is assembled so as to be relatively rotatable with the member, and is driven and rotated by power from the driving force transmission member; a housing member that rotates integrally with the driving force transmission member; and is accommodated in the housing member, A vane member that rotates integrally with the camshaft, an advance hydraulic chamber and a retard hydraulic chamber that are provided in the housing member and rotate the vane member by hydraulic pressure, and the advance hydraulic chamber and the retard hydraulic pressure A hydraulic intake / exhaust means that communicates with the chambers and selectively absorbs / discharges hydraulic pressure to / from these hydraulic chambers, and is provided between the vane member and the housing member to Flip provided with a rotation restricting means for restricting the relative rotation between the vane member and the housing member,
  A light weight portion is provided in the driving force transmission member so that the mass distribution of the driving force transmission member is asymmetric about the rotation axis,When the relative rotation between the vane member and the housing member is restricted by the rotation restricting means, the disposition positions of the lightweight portion and the rotation restricting means are determined.The light-weight part is substantially matched with the driving force transmission part.MaterialConstituted by a thin portion provided on at least one side ofThe driving force transmitting member is formed of a member having a large specific gravity with respect to a member that increases in weight with the addition of the rotation restricting means of the housing member and the vane member.
[0013]
  In the case of the present invention, the partial weight increase around the rotation axis due to the provision of the rotation restricting means is offset by the partial weight decrease by the lightweight portion of the driving force transmission member. Therefore, the center of gravity of the apparatus can be brought closer to the rotation axis.
[0014]
  According to a second aspect of the present invention, the amount of decrease in the moment of inertia of the driving force transmission member due to the provision of the thin portion is substantially equal to the amount of increase in the moment of inertia due to the provision of the rotation restricting means. It is characterized by that.
[0015]
  In the case of the present invention, the increase in the inertia moment due to the provision of the rotation restricting means is offset by the decrease in the inertia moment of the driving force transmission member due to the provision of the lightweight portion. Therefore, the center of gravity of the apparatus is located on the rotation axis.
[0016]
  The invention according to claim 3 is characterized in that the thin portion is provided on a plane perpendicular to the rotation axis of the driving force transmission member and is formed thinner than a general portion of the plane. .
[0017]
  In the case of this invention, since the light-weight portion is not a structure that completely penetrates the wall of the driving force transmission member by reducing the light-weight portion, the rigidity of the driving force transmission member is less likely to occur.
[0018]
  The invention described in claim 4 is characterized in that a plurality of the thin portions are provided in substantially the same shape.
[0019]
  In the case of this invention, it becomes easier to form compared to forming one thin portion, and the rotation balance can be easily adjusted by changing the formation position and number of thin portions. .
[0020]
DETAILED DESCRIPTION OF THE INVENTION
  Next, embodiments of the present invention will be described with reference to the drawings.
[0021]
  1 to 5 show an embodiment of the present invention. In FIG. 2, reference numeral 1 denotes an engine camshaft. The camshaft 1 is rotatably supported by a cylinder head (not shown) via a bearing, and a drive cam (not shown) for opening and closing an intake valve as an engine valve is provided on the outer periphery of the trunk portion. Yes. The valve timing control device 2 according to the present invention is provided on one end side of the camshaft 1.
[0022]
  Valve timing control device22 and 3, a chain sprocket 4 as a driving force transmission member that is rotationally driven by a crankshaft (not shown) through a timing chain 3 and a front end portion of the chain sprocket 4 The housing member 5 that is integrally coupled, the camshaft 1 that is assembled so that the chain sprocket 4 and the housing member 5 can be rotated as necessary at one end, and a sleeve 6 at one end of the camshaft 1 A vane member 7 that is integrally assembled and rotatably accommodated in the housing member 5, a hydraulic intake / exhaust means 8 that rotates the vane member 7 forward and backward by hydraulic pressure according to the operating state of the engine, and the camshaft. Rotation restriction that restricts the return of the vane member 7 due to the positive rotational fluctuation torque acting on 1 according to the operating state Is provided with a stage 9, the.
[0023]
  The housing member 5 includes a substantially cylindrical housing body 10, and a front cover 12 and a rear cover 13 connected to the front and rear end faces of the housing body 10 by bolts 11. As shown in FIG. 3, four partition walls 14 each having a trapezoidal cross section are provided at 90 ° intervals. 2, reference numerals 15a and 15b denote positioning pins for positioning the three parts of the chain sprocket 4, the rear cover 13, and the housing body 10 and between the housing body 10 and the front cover 12, respectively.
[0024]
  On the other hand, the vane member 7 projects from the camshaft 1 to the camshaft 1 together with a sleeve 6 together with a bolt (not shown) and a substantially cylindrical body portion 16 and radially protrudes from the outer peripheral surface of the body portion 16 at 90 ° intervals. The body portion 16 is disposed at the axial center position of the housing member 10, and each blade portion 17 is disposed between the adjacent partition walls 14, 14 of the housing member 5. . The space between one side surface of each vane portion 17 of the vane member 7 and the partition wall 14 facing it is an advance hydraulic chamber 18, and the other side surface of each blade portion 17 and the partition wall 14 facing it are arranged. The interval is a retarded hydraulic chamber 19. Therefore, in this apparatus, a total of four pairs of the advance hydraulic chamber 18 and the retard hydraulic chamber 19 are provided. A spring-biased seal member 20 is attached to each blade portion 17 and the distal end portion of the partition wall 14 to achieve liquid tightness between the adjacent hydraulic chambers 18 and 19.
[0025]
  Further, a circular concave portion 21 is provided on the front side of the body portion 16 of the vane member 7, and the end portion of the first radial hole 22 communicating with each advance hydraulic chamber 18 and each retard hydraulic pressure. The ends of the second radial holes 23 communicating with the chamber 19 are opened on the inner peripheral surface of the recess 21. Each end of the first radial hole 22 and the second radial hole 23 opens at a position offset in the axial direction in the recess 21.
[0026]
  A cylindrical shaft member 24 extending to a front cover (not shown) of the engine is fitted in the recess 21 of the vane member 7 so as to be relatively rotatable. The hydraulic oil is sucked into and discharged from the advance hydraulic chamber 18 and the retard hydraulic chamber 19 through the member 24.
[0027]
  As shown in FIG. 2, the hydraulic suction / discharge means 8 includes a first hydraulic passage 25 that sucks and discharges hydraulic pressure from the advance hydraulic chamber 18 and a second hydraulic passage 26 that sucks and discharges hydraulic pressure from the retard hydraulic chamber 19. Two hydraulic passages are provided, and a supply passage 27 and a drain passage 28 are connected to both of the hydraulic passages 25 and 26 via a passage switching electromagnetic switching valve 29, respectively. The supply passage 27 is provided with an oil pump 31 that pumps oil in the oil pan 30, and an end portion of the drain passage 28 communicates with the oil pan 30. The electromagnetic switching valve 29 is controlled by a controller 32, and various signals indicating the operating state of the engine are input to the controller 32.
[0028]
  3 and 4, a plurality of crank angle determination phase grooves 33 are formed along the axial direction on the outer peripheral surface of the housing member 5, and the phase grooves 33 are constant on the outer periphery of the housing member 5. The arrangement number is changed for each angular pitch, and the generated pulse changes for every constant crank angle. A non-illustrated pulse detection device such as a magnetic detection element is disposed at a position close to the housing member 5, and the crank angle can be detected by detecting the generated pulse with this detection device. . This detection signal is input to the controller 32.
[0029]
  The first hydraulic passage 25 has a first shaft hole 34 formed along the axial center direction of the shaft member 24 from the front cover 12 of the engine, and the shaft member 24 so as to intersect the first shaft hole 34. A first radial hole 35 formed in the vicinity of the tip of the first annular groove 36, a first annular groove 36 formed on the outer peripheral surface of the shaft member 24 so as to communicate with the first radial hole 35, and the first The annular groove 36 and the first radial hole 22 of the vane member 7 communicating with each advance hydraulic chamber 18. Similarly, the second hydraulic passage 26 includes a second shaft hole 37 formed along the axial direction of the shaft member 24, a second radial hole 38 intersecting the shaft hole 37, and a shaft member. A second annular groove 39 formed on the outer peripheral surface of the second communication hole 24 and communicated with the second radial hole 38, and a second diameter of the vane member 7 communicating with the second annular groove 39 and each retarded hydraulic chamber 19. And a direction hole 23. In this embodiment, the tip end portion of the second shaft hole 37 opens toward the recess 21 of the vane member 7. However, the tip end portion may be closed without being opened.
[0030]
  Accordingly, hydraulic oil is selectively passed through the first hydraulic passage 25 and the second hydraulic passage 26 formed from the shaft member 24 to the vane member 7 in the advance hydraulic chamber 18 and the retard hydraulic chamber 19 inside the housing member 5. It is sucked and discharged.
[0031]
  The rotation restricting means 9 mechanically locks the relative rotation of the housing member 5 and the vane member 7 when the vane member 7 is controlled to rotate to the retard side when the engine is started. A lock pin 40 accommodated and supported by the vane member 7 so as to be movable forward and backward along the radial direction; a spring member 41 that urges the lock pin 40 in the protruding direction (outside in the radial direction); and an inner periphery of the housing member 5 And a fitting hole 42 into which the tip of the lock pin 40 is fitted at a position where the vane member 7 is displaced to the maximum in the retarding direction with respect to the housing member 5.
[0032]
  The lock pin 40 is accommodated in one of the four blade portions 17 of the vane member 7. More specifically, as shown in FIG. 3, one vane portion 17 of the vane member 7 bulges in a step shape toward the advance hydraulic chamber 18 side, and the outer surface of the bulged portion 43 extends along the radial direction. A cylinder hole 44 is formed, and the lock pin 40 is slidably accommodated in the cylinder hole 44 via a collar 45. The collar 45 is made of a material harder than the vane member 7 and is press-fitted and fixed so as to be biased toward the opening side of the cylinder hole 44. Note that the housing member 5 faces the bulging portion 43 of the vane member 7 with a set minute gap d when the vane member 7 is displaced to the maximum in the retarding direction (advancing hydraulic chamber 18 direction). A stepped portion 46 corresponding to the bulging portion 43 is provided.
[0033]
  The lock pin 40 is generally formed in a bottomed cylindrical shape, and a stopper flange 47 capable of contacting the end surface of the collar 45 extends on the outer periphery of the base end portion accommodated in the cylinder hole 44. It is installed. The stopper flange 47 abuts against the end face of the collar 45 to restrict the displacement of the lock pin 40 in the protruding direction, thereby preventing the pin 40 from being detached from the vane member 7 and the vane member 7 to advance. The tip of the lock pin 40 is prevented from coming into contact with the inner peripheral surface of the housing member 5 when rotated to the corner side.
[0034]
  The lock pin 40 is formed hollow with the tip portion remaining, and the spring member 41 that urges the pin 40 in the protruding direction is disposed in the hollow portion 48. And the front-end | tip part of the lock pin 40 which protrudes from the cylinder hole 44 is formed in the shape of a truncated cone, and the hollow 49 for receiving the hydraulic pressure mentioned later is formed in the front-end | tip surface. The lock pin 40 is also reduced in weight by the hollow portion 48 and the recess 49. As shown in FIG. 2, a vent hole 50 is formed in the body portion 16 of the vane member 7 so that the bottom of the cylinder hole 44 communicates with the outside of the apparatus, so that the bottom of the cylinder hole 44 is maintained at atmospheric pressure. It has become.
[0035]
  On the other hand, the fitting hole 42 into which the tip of the lock pin 40 is fitted is not formed directly in the housing member 5 (housing main body 10), but is formed in a separate plug 51 made of a hard material. The plug 51 is fitted and fixed to the stepped portion 46 of the housing member 5 along the radial direction. The fitting hole 42 of the plug 51 is formed in a cup shape with a front opening so that the tip of the lock pin 40 can be fitted, and the fitting hole 42 has a gap between the step portion 46 and the bulging portion 43. A hydraulic pressure introducing groove 52 that communicates d and the bottom of the fitting hole 42 is formed. Therefore, the bottom portion of the fitting hole 42 is always connected to the advance hydraulic chamber 18 through the hydraulic pressure introducing groove 52 and the gap d.
[0036]
  Further, the stepped portion 46 of the housing member 5 rises in the axial direction from the inner peripheral surface of the general portion where the vane portion 17 of the vane member 7 is displaced, and the rising wall is arranged with the fitting hole 42. The taper surface 53 is gentle toward the installation position. Therefore, even when the vane member 7 is displaced from the advance side (retarding hydraulic chamber 19 side) toward the retarding side (advancing hydraulic chamber 18 side), the lock pin 40 is guided by the tapered surface 53. Then, it is smoothly compressed in the backward direction, gets over the hole edge of the fitting hole 42 and is finally fitted into the fitting hole 42.
[0037]
  Here, since the valve timing control device is provided with the rotation restricting means 9 between the vane member 7 and the housing member 5 as described above, the bulging portion 43 of the vane member 7 and the step portion 46 of the housing member 5 are provided. As a result, the mass is partially increased, and as a result, the mass distribution around the rotation axis O of the vane member 7 and the housing member 5 is not uniform and greatly deviates toward the installation side of the rotation restricting means 9.倚is doing.
[0038]
  In the valve timing control device 2, the chain sprocket 4 coupled to the rear end face of the housing member 5 is used to cancel out the non-uniformity in the mass distribution of the vane member 7 and the housing member 5.Through hole54 so that the chain sprocket 4 is partially provided with a lighter portion.
[0039]
  In this embodiment,Through holeAs shown in FIG. 1, three substantially rectangular shapes 54 are provided along the circumferential direction of the chain sprocket 4, and the arrangement is biased to the upper right side in FIG. As shown in FIG. 5, the through-hole 54 penetrates the chain sprocket 4 having a uniform thickness in the axial direction (a plane perpendicular to the rotation axis O).To penetrate), The position of the center of gravity of the chain sprocket 4 is biased obliquely downward to the left in FIG. That is, the chain sprocket 4 isThrough holeThe diagonally upper right side of the chain sprocket 4 is lighter by the amount 54 is provided.
[0040]
  SaidThrough hole54, when the chain sprocket 4 is coupled to the housing member 5 as shown in FIG. 4, the mass distribution around the rotation axis O of the vane member 7 and the housing member 5 due to the provision of the rotation restricting means 9 is reduced. It is provided to cancel out the uniformity. Specifically, threeThrough holeThe chain sprocket 4 is attached to the housing member 5 so that the central one of 54, 54, 54 is positioned substantially corresponding to the position where the rotation restricting means 9 is disposed, and the bulging portion 43 is provided on the vane member 7. The increase in mass due to the fact that the step 46 is provided in the housing member 5Through holeIt is offset by 54 mass loss.
[0041]
  In this embodiment, from the rotation axis OThrough holeThe distance to 54 is also set accurately, and the increase in the moment of inertia due to the provision of the bulging portion 43 and the stepped portion 46 in the vane member 7 and the housing member 5 is given to the chain sprocket 4.Through holeBy providing 54, the amount of inertia is almost completely offset by the decrease in the moment of inertia.
[0042]
  To explain further, from the rotation axis OThrough holeThe influence of the distance to 54 increases as the distance is increased, that is, the closer the through hole 54 is to the outer peripheral side of the chain sprocket 4. Therefore,Through holeDecrease in mass due to 54, maThrough holeMa × la where the distance to the center of 54 is la²The center of gravity of the valve timing control device 2 and the rotation axis O can be obtained by matching the amount of inertia moment reduction and the amount of inertia moment increase due to the bulging portion 43 of the vane member 7 and the step portion 46 of the housing member 5. Can be almost matched.
[0043]
  In this embodiment, the housing member 5 and the vane member 7 are formed of an aluminum alloy, and the chain sprocket 4 is formed of an iron-based material having a specific gravity higher than that of the aluminum alloy. Therefore, the chain sprocket 4 having a large specific gravity was formed.Through holeThe effect that 54 has on the entire device becomes very large,Through holeIt is possible to minimize the reduction in the strength of the chain sprocket 4 by minimizing the opening area 54 and the number of installations.
[0044]
  Further, as described above, in the case of this embodiment, the phase grooves 33 are formed on the outer peripheral surface of the housing member 5 (housing main body 10). The portion corresponding to the arrangement position is set to be the maximum. That is, in this embodiment, as shown in FIGS. 3 and 4, the number of arrangement of the phase grooves 33 on the outer peripheral surface of the housing member 5 is changed to 1, 2, 4, 2 at intervals of about 90 °. The portion where the number of arrangement is four is set so as to be almost at the position where the rotation restricting means 9 is disposed. Accordingly, the portion of the housing member 5 corresponding to the rotation restricting means is partially reduced in weight by the phase groove 33.
[0045]
  It continues and demonstrates the effect | action of this embodiment.
[0046]
  In this structure, when the hydraulic oil is not sufficiently supplied from the oil pump 31 at the time of starting the engine, or when high-pressure hydraulic oil is supplied to the retarded hydraulic chamber 19 by operating the electromagnetic switching valve 29, the vane member 7 is disposed in the housing. The lock pin 40 of the rotation restricting means 9 receives the urging force and centrifugal force of the spring member 41 at this time, and the tip end of the lock pin 40 is fitted in the fitting hole 42 with respect to the member 5. The vane member 7 and the housing member 5 are mechanically connected. For this reason, the rotational driving force input from the crankshaft (not shown) to the chain sprocket 4 via the timing chain 3 is connected to the camshaft via the housing member 5 and the vane member 7 which are mechanically coupled in the most retarded state. 1 and opens and closes the intake valve at a retarded angle via a drive cam (not shown). At this time, the side surface of the bulging portion 43 of the vane member 7 is maintained in a slightly separated state without coming into contact with the side surface of the partition wall 14 facing it.
[0047]
  When the vane member 7 is pivotally displaced to the most retarded angle side as described above, the lock pin 40 is fitted into the fitting hole 42 as described above to mechanically connect the housing member 5 and the vane member 7. Because of the coupling, the vane member 7 does not rotate relative to the housing member 5 even when positive or negative fluctuation torque is input from the intake valve to the camshaft 1. There is no problem that the blade portion 17 collides with the partition wall 14 to generate a hitting sound or the like.
[0048]
  In this state, when the controller 32 controls the electromagnetic switching valve 29, the advance hydraulic chamber 18 communicates with the supply passage 27 and the retard hydraulic chamber 19 communicates with the drain passage 28. High-pressure hydraulic oil is introduced, and at this time, the high-pressure operation is also performed through the gap d between the bulging portion 43 and the stepped portion 46 and the hydraulic pressure introduction groove 52 on the tip side of the lock pin 40 (bottom portion of the fitting hole 42). Oil is introduced. As a result, the lock pin 40 receives the pressure of the hydraulic oil and receives a pressing force in the backward direction. This pressing force resists the centrifugal force acting on the lock pin 40 and the urging force of the spring member 41. Can be pushed into the cylinder hole 44 of the vane member 7. As a result, the tip of the lock pin 40 is completely detached from the fitting hole 42 on the housing member 5 side, and the mechanical rotation restriction of the housing member 5 and the vane member 7 by the lock pin 40 is released.
[0049]
  On the other hand, each vane portion 17 of the vane member 7 receives a differential pressure between the advance hydraulic chamber 18 and the retard hydraulic chamber 19, and the vane member 7 as a whole is advanced with respect to the housing member 5 (the retard hydraulic chamber 19 direction). To stop at the most advanced position. As a result, the chain sprocket 4 and the camshaft 1 are relatively rotated, and the rotational phase of the camshaft 1 with respect to the chain sprocket 4 is controlled to the advance side.
[0050]
  Thus, while the rotational phase of the camshaft 1 with respect to the chain sprocket 4 is controlled to the advance side, the high pressure of the oil pump 31 continues to act on the advance hydraulic chamber 18. 44 is maintained in the state of being retracted.
[0051]
  Subsequently, when the retard hydraulic chamber 19 communicates with the supply passage 27 and the advance hydraulic chamber 18 communicates with the drain passage 28 by the control of the electromagnetic switching valve 29 by the controller 32 from this state, the retard hydraulic chamber 19 enters the retard hydraulic chamber 19. High-pressure hydraulic oil is introduced and hydraulic oil in the advance hydraulic chamber 18 is discharged into the oil pan 30.
[0052]
  As a result, the differential pressure between the retard hydraulic chamber 19 and the advance hydraulic chamber 18 acts on each vane portion 17 of the vane member 7, and the entire vane member 7 receives this differential pressure to retard the housing member 5. It rotates in the direction (advanced hydraulic chamber 18 direction). At this time, since the advance hydraulic chamber 18 facing the tip of the lock pin 40 is at atmospheric pressure, the lock pin 40 protrudes due to the centrifugal force and the urging force of the spring member 41. Since the protruding height of the vane member 7 is regulated by the contact between the stopper flange 47 and the collar 45, the vane member 7 does not move the tip of the pin 40 relative to the housing member 5 until the lock pin 40 reaches the position of the tapered surface 53. Rotate while maintaining contact.
[0053]
  Then, when the rotation of the vane member 7 with respect to the housing member 5 progresses and the tip of the lock pin 40 comes into contact with the taper surface 53, the lock pin 40 is gradually guided by the taper surface 53 and rides on the stepped portion 46 to be fitted. It gets over the hole edge of the mating hole 42 and is fitted into the hole 42. As a result, the vane member 7 is mechanically connected again to the housing member 5 at the most retarded position, and the rotational phase of the camshaft 1 relative to the chain sprocket 4 is controlled to the retarded side.
[0054]
  Further, the valve timing control in the state of the most retarded angle and the most advanced angle has been described above. However, when the vane member 7 is at an arbitrary position between the most retarded angle position and the most advanced angle position, the electromagnetic switching valve is used. If both the first hydraulic passage 25 and the second hydraulic passage 26 are closed, the intake valve can be opened and closed at an arbitrary valve timing according to the rotational position of the vane member 7. At this time, since the advance hydraulic chamber 18 is maintained in a sealed state, hydraulic pressure acts on the tip of the lock pin 40, and the engagement between the vane member 7 and the housing member 5 by the lock pin 40 is released. Has been.
[0055]
  As described above, the valve timing control device 2 is rotated at a high speed by the crankshaft of the engine. In most cases, the valve timing is controlled during the high-speed rotation, so that the center of gravity of the device 2 is eccentric with respect to the rotation axis O. It is not preferable. However, the valve timing control device 2 of this embodiment has a plurality of planes on a plane perpendicular to the rotation axis O of the chain sprocket 4.Through hole54 is arranged in a part of the circumferential direction so that the mass distribution of the sprocket 4 is asymmetric about the rotation axis, and the arrangement angle of the through-hole 54 and the arrangement angle of the rotation restricting means 9 are substantially matched, And,Through holeThe amount of decrease in the moment of inertia of the sprocket 4 due to 54 is set to coincide with the amount of increase in the moment of inertia due to the provision of the bulging portion 43 and the stepped portion 46 in the vane member 7 and the housing member 5. The center of gravity of 2 is almost located on the rotation axis O, and rotation imbalance hardly occurs.
[0056]
  Therefore, in this device 2, the rotation balance can be properly maintained without any modification to the vane member 7 and the housing member 5. However, in this embodiment, the phase groove 33 is set so that the portion where the number of the phase grooves 33 on the outer periphery of the housing member 7 is maximized is almost at the position where the rotation restricting means 9 is disposed. Also contributes to the adjustment of the rotation balance. If the arrangement of the phase grooves 33 is devised as in this embodiment, the partial thickness reduction (processing amount) with respect to the chain sprocket 4 can be reduced, and the rigidity reduction of the sprocket 4 can be further reduced. .
[0057]
  The embodiment of the present invention is not limited to the above-described embodiment, and instead of forming the through hole 54 as a means for providing a lightweight portion in the driving force transmission member such as the chain sprocket 4 as shown in FIG. Alternatively, the thin portions 55 may be provided on both the front and back surfaces of the sprocket 4 or the like, or on one side surface. When the light-weight portion is configured by providing the thin-walled portion 55 in this manner, the rigidity reduction of the drive transmission member such as the chasprocket 4 is reduced and the deformation is small as compared with the case where the through-hole 54 is provided. There is an advantage that it can be structured. However, in the case where the light-weight portion is configured by the through hole 54 as in the above-described embodiment, there is an advantage that the manufacturing cost can be reduced because the processing is easy.
[0058]
  In the embodiment described above, a plurality of substantially rectangular through holes 54 are formed in the chain sprocket 4 so as to be biased to a part in the circumferential direction, but the through holes 154 are formed on the chain sprocket 4 as shown in FIG. Only one may be formed. In this case, there is an advantage that the number of the through holes 154 can be reduced, so that the manufacture becomes easy.
[0059]
  In addition, the figure8As shown, the through hole 254 formed in the chain sprocket 4 may be formed in a circular shape instead of a substantially rectangular shape. This is also true for the embodiment described above,Through hole254 (54) is formed when a plurality of the same shape is formed instead of one.Through holeBy changing the number and arrangement of 254 (54), an advantageous effect that it is possible to easily cope with delicate balance adjustment and design change is obtained. In particular, as shown in FIG. 8, when a plurality of through holes 254 are formed in a circular shape, when the through holes 56 for bolt connection are drilled in the chain sprocket 4, the through holes 254 are simultaneously formed in a drilling machine or the like. There is an advantage that it can be formed easily. Therefore, the device of the present application can be obtained by simply drilling the existing chain sprocket 4.
[0060]
  In addition, the chain sprocket 4Through-hole 54 andAlthough the example which comprises a lightweight part by providing the thin part 55 was demonstrated, you may make it comprise a lightweight part by providing partially the material with small specific gravity in the chain sprocket 4. FIG. Then, in addition to providing a light weight part in the driving force transmission member such as the chain sprocket 4 or the like, it is of course possible to balance the rotation of the apparatus by changing the layout inside the housing member 5. is there.
[0061]
【The invention's effect】
  As described above, in the first aspect of the present invention, the partial weight increase around the rotation shaft due to the provision of the rotation restricting means is caused by the partial weight decrease by the light weight portion of the driving force transmission member. Since the center of gravity of the device can be brought closer to the rotating shaft without offsetting and making any design changes to the vane member or housing member, the weight balance with respect to the rotating shaft without causing problems such as an increase in the size of the device or an increase in weight. It is possible to improve the stability of the operation of the apparatus, and to prevent generation of vibration noise and early wear of components such as bearings. Furthermore, in the present invention, the housing member that has already been reduced in weight to near the limit does not need to be subjected to a blanking process, so the required strength of the housing member can be maintained.The
[0062]
  In addition, since the driving force transmission member is formed of a member having a large specific gravity with respect to a member that increases in weight with the addition of the rotation restricting means of the housing member and the vane member, the driving force transmission member is slightly different from the driving force transmission member. Rotational balance can be adjusted with certainty.
[0063]
  The invention according to claim 2 can cancel the increase in the inertia moment due to the provision of the rotation restricting means by the decrease in the inertia moment of the driving force transmission member due to the provision of the lightweight portion. The rotation imbalance due to the provision of the rotation restricting means can be almost completely eliminated.
[0064]
  In the invention according to claim 3, the thin portion is provided on a plane perpendicular to the rotation axis of the driving force transmission member, and is configured by the thin portion formed thinner than the general portion of the plane. The rotational imbalance of the apparatus can be eliminated without causing a decrease in rigidity of the force transmission member.
[0065]
  In the invention according to claim 4, since a plurality of thin portions are provided in substantially the same shape, processing is facilitated and manufacturing at low cost is possible, and by changing the formation position and number of thin portions. It is easy to adjust the rotation balance and change the design.
[Brief description of the drawings]
FIG. 1 is a front view of a chain sprocket corresponding to an arrow A in FIG. 2 showing an embodiment of the present invention.
2 is a cross-sectional view taken along the line CC of FIG. 3 showing the embodiment.
3 is a cross-sectional view taken along line BB in FIG. 2 showing the embodiment. FIG.
FIG. 4 is a perspective view of a main part showing the embodiment.
5 is a cross-sectional view taken along the line DD of FIG. 1 showing the embodiment. FIG.
[Fig. 6]Sectional drawing corresponding to the cross section along the DD line of FIG. 1 which shows other embodiment of this invention.
[Fig. 7]The front view corresponding to the A arrow of FIG. 2 of the chain sprocket which shows other embodiment of this invention.
[Fig. 8]The front view corresponding to A arrow of FIG. 2 of the chain sprocket which shows another embodiment of this invention.
[Explanation of symbols]
1 ... Camshaft
2… Valve timing control device
4. Chain sprocket (drive force transmission member)
5 ... Housing member
7 ... Vane material
8 ... Hydraulic suction / discharge means
9 ... Rotation restricting means
18 ... Advance hydraulic chamber
19 ... retarded hydraulic chamber
54 ... PenetrationHole(Lightweight part)
55 ... Thin part (lightweight part)

Claims (4)

A driving force transmission member driven by a crankshaft of the internal combustion engine;
A camshaft having a drive cam for operating an engine valve on an outer periphery, assembled so as to be relatively rotatable with the drive force transmission member, and driven to rotate by power from the drive force transmission member;
A housing member that rotates integrally with the driving force transmission member;
A vane member housed in the housing member and rotated integrally with the camshaft;
An advance hydraulic chamber and a retard hydraulic chamber that are provided in the housing member and rotate the vane member by hydraulic pressure;
A hydraulic intake / exhaust means that communicates with the advance hydraulic chamber and the retard hydraulic chamber and selectively absorbs / discharges hydraulic pressure to / from these hydraulic chambers;
A rotation restricting means provided between the vane member and the housing member and restricting relative rotation of the vane member and the housing member in accordance with an operating state of the internal combustion engine;
A light weight portion is provided in the driving force transmission member so that the mass distribution of the driving force transmission member is asymmetric about the rotation axis,
When the relative rotation of the vane member and the housing member is restricted by the rotation restricting means, the light-weight portion and the rotation restricting means are substantially aligned with each other, and the light-weight portion is driven. constituted by the thin portion provided on at least one side surface of the force transmitting member,
The valve timing of an internal combustion engine, wherein the driving force transmitting member is formed of a member having a large specific gravity with respect to a member that increases in weight with the addition of the rotation restricting means of the housing member and the vane member. Control device.   The reduced amount of the moment of inertia of the driving force transmission member due to the provision of the thin portion is substantially equal to the amount of increase of the moment of inertia due to the provision of the rotation restricting means. A valve timing control device for an internal combustion engine according to claim 1.   3. The internal combustion engine according to claim 1, wherein the thin portion is provided on a plane perpendicular to a rotation axis of the driving force transmission member and is formed thinner than a general portion of the plane. Engine valve timing control device.   The valve timing control device for an internal combustion engine according to any one of claims 1 to 3, wherein a plurality of the thin portions are provided in substantially the same shape.

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