CN116255219A - Valve timing control device - Google Patents

Abstract

The invention provides a valve timing control device capable of discharging lubricating oil for lubricating sliding parts in the device and early. The valve timing control device 100 includes a driving-side rotating body a, a driven-side rotating body, and a phase adjustment mechanism that sets a relative rotational phase of the driving-side rotating body a and the driven-side rotating body, and the phase adjustment mechanism includes an output gear 25 that is coaxially provided with a rotation axis X and is provided to the driven-side rotating body, an input gear 30 that is coupled to the driving-side rotating body a, and a cylindrical eccentric member 26 that rotates the input gear 30. The driving-side rotating body a has a front plate 12 on the opposite side of the cam shaft from the eccentric member 26 in the direction along the rotation axis X, and the front plate 12 has an opening 12b for discharging the lubricating oil supplied to the driven-side rotating body to the outside at least in a portion facing the input gear 30.

Description

Valve timing control device

Technical Field

The present invention relates to a valve timing control apparatus.

Background

Patent document 1 describes a valve timing control device for controlling the opening and closing timing of a valve in a cam portion of a camshaft by transmitting torque from a crankshaft in an internal combustion engine. The valve timing control device is provided with a drive-side rotating body, a driven-side rotating body, and a phase adjustment mechanism for setting the relative rotational phase of the drive-side rotating body and the driven-side rotating body. The phase adjustment mechanism includes an output gear coaxially provided on the driven-side rotating body with the rotation shaft center, an input gear that rotates around an eccentric shaft center in a parallel posture with the rotation shaft center and is coupled to the driving-side rotating body, a first bearing, a second bearing, a cylindrical eccentric member that supports the input gear from the inner peripheral side via the second bearing and rotates the input gear, and the like.

The valve timing control apparatus generally supplies lubricating oil to the inside of the driven-side rotating body when the engine is operating. In the valve timing control device described in patent document 1, the driving-side rotating body has a front plate on the opposite side of the eccentric member from the camshaft in the direction along the rotation axis. The front plate is circular when viewed in the direction of the rotation axis and has a circular opening in the center. The opening is provided for discharging the lubricating oil in the inner space of the eccentric member to the outside.

Patent literature

Patent document 1: japanese patent laid-open No. 2021-17833

Disclosure of Invention

In the valve timing control apparatus, there are a plurality of portions (hereinafter, also referred to as "sliding portions") that slide, for example, portions where the input gear and the output gear mesh with each other, inside the apparatus during operation, and lubricating oil is supplied to the sliding portions. In the valve timing control device described in patent document 1, the front plate has a circular opening in the center, and is formed so as to entirely cover the input gear and the output gear. Thus, when the engine is operated, it is difficult for the lubricant oil for lubricating the sliding portion inside the device to be discharged from the front plate to the outside. In particular, in a cold environment where the viscosity of the lubricating oil increases, the shearing resistance of the lubricating oil retained in the device increases. If the high-viscosity lubricating oil stagnates in the sliding portions inside the device, the responsiveness of the valve timing control device may be lowered. In addition, in the valve timing control device, there are cases where abrasion powder or foreign matter is mixed into the lubricating oil in the sliding portion inside the device. In this case, abrasion powder or foreign matter that has remained in the device together with the lubricating oil may increase abrasion of the sliding portion.

The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a valve timing control device capable of discharging lubricating oil for lubricating a sliding portion inside the device to the outside early.

In order to achieve the above object, a valve timing control apparatus according to the present invention is characterized in that: the engine is provided with a drive side rotating body which rotates in synchronization with a crankshaft of the engine around a rotation axis, a driven side rotating body which is concentric with the rotation axis and is disposed inside the drive side rotating body and rotates integrally with a camshaft for opening and closing a valve of the engine, and a phase adjustment mechanism which sets a relative rotation phase of the drive side rotating body and the driven side rotating body, the phase adjustment mechanism including an output gear which rotates coaxially with the rotation axis and is disposed on the driven side rotating body around an eccentric axis which is parallel to the rotation axis and is connected to the drive side rotating body, an input gear which is supported from an inner peripheral side by a support bearing and rotates the input gear, an input gear which is configured to revolve around the eccentric axis by rotation of the eccentric member, thereby changing a position of an engagement portion of the output gear and the input gear, and a cylindrical eccentric member which has an oil passage which is capable of supporting the driven side rotating body in a direction opposite to the rotation axis from the inner peripheral side to the camshaft, the driven side rotating body having an oil passage which is capable of being supplied to the inner peripheral side of the camshaft, the driven side rotating plate having a position opposite to the rotation axis, the front plate has an opening for discharging the lubricant supplied to the driven-side rotating body to the outside at least in a portion facing a part of the input gear.

The valve timing control device is configured such that a plurality of sliding portions exist in the device at and near the portion where the input gear meshes with the output gear, and lubricating oil supplied from the outside to the inside of the driven-side rotating body is supplied to the sliding portions. In this structure, the front plate is formed with an opening for discharging the lubricant oil supplied to the driven-side rotating body to the outside at least in a portion facing a part of the input gear. Thus, the valve timing control apparatus can early discharge the lubricating oil for lubricating the sliding portion in the vicinity of the input gear from the opening of the front plate to the outside. Further, in the valve timing control apparatus, since the opening of the front plate is provided close to the sliding portion, even if abrasion powder or foreign matter is mixed in the lubricating oil for lubricating the sliding portion, or abrasion powder or foreign matter is generated in the sliding portion due to sliding, the abrasion powder or foreign matter can be discharged to the outside together with the lubricating oil from the opening. As a result, abrasion in the device other than the sliding portion due to the mixing of abrasion powder and foreign matter into the lubricating oil can be suppressed. Further, since the lubricant oil for lubricating the sliding portion is easily discharged from the opening of the front plate to the outside, the lubricant oil does not remain around the sliding portion, and therefore, the responsiveness of the valve timing control apparatus can be improved even in a cold environment in which the viscosity of the lubricant oil is high.

A further feature of the valve timing control apparatus according to the present invention is that: the phase adjustment mechanism further includes an oldham coupling having an inner engagement arm protruding radially outward about the rotation axis and an engagement recess formed inside the inner engagement arm, the input gear having an engagement protrusion, the input gear being coupled to the driving-side rotating body by engagement of the engagement protrusion with the engagement recess of the oldham coupling, and the opening being formed so as to oppose an entire area of the engagement protrusion of the input gear that slides radially with respect to the engagement recess of the oldham coupling.

In the valve timing control apparatus, the phase adjustment mechanism may have an oldham coupling. The oldham coupling of the phase adjustment mechanism is displaced in the radial direction around the rotation axis by the influence of the displacement of the input gear, and in this case, the engagement concave portion of the oldham coupling slides with respect to the engagement protrusion of the input gear, thereby generating abrasion powder. Therefore, in this structure, the opening of the front plate is formed so as to oppose the entire area in which the engagement projection of the input gear slides in the radial direction with respect to the engagement recess of the oldham coupling. Thus, the valve timing control device can discharge the lubricating oil for lubricating the sliding portion between the engagement concave portion of the oldham coupling and the engagement protrusion of the input gear to the outside from the opening of the front plate early. Further, even if abrasion powder or foreign matter is mixed in the lubricating oil for lubricating the sliding portion of the engagement concave portion of the oldham coupling and the engagement protrusion of the input gear, or the abrasion powder or foreign matter is generated in the sliding portion due to the sliding, the valve timing control apparatus can discharge the abrasion powder or foreign matter together with the lubricating oil from the opening of the front plate to the outside.

A further feature of the valve timing control apparatus according to the present invention is that: the opening is formed so as to oppose a region of the meshing portion of the input gear and the output gear that spans from a root of the external gear portion of the input gear to a root of the internal gear portion of the output gear.

In the valve timing control apparatus, there is a meshing portion of an input gear and an output gear as a sliding portion inside the apparatus. Therefore, the valve timing control apparatus is configured to also supply the lubricating oil supplied from the outside to the inside of the driven-side rotating body to the meshing portion of the input gear and the output gear. Therefore, in the present structure, the opening of the front plate is formed so as to oppose a region spanning from the root of the external tooth portion of the input gear to the root of the internal tooth portion of the output gear in the meshing portion of the input gear and the output gear. Thus, in the valve timing control apparatus, even if abrasion powder or foreign matter is generated due to sliding of the meshing portion of the input gear and the output gear, they can be discharged to the outside from the opening of the front plate together with the lubricating oil as early as possible. Further, even if abrasion powder or foreign matter is mixed in the lubricating oil that lubricates the meshing portions of the input gear and the output gear, the valve timing control apparatus can discharge the abrasion powder or foreign matter to the outside together with the lubricating oil from the opening of the front plate.

A further feature of the valve timing control apparatus according to the present invention is that: the opening is formed to face a region larger than an operation region in which the engagement recess of the oldham coupling and the engagement projection of the input gear move in a circumferential direction while sliding in a radial direction.

The oldham coupling of the phase adjustment mechanism is displaced in a radial direction around the rotation axis due to the displacement of the input gear. Therefore, it is conceivable that the valve timing control device has an operation region in which the engagement recess of the oldham coupling and the engagement projection of the input gear move in the circumferential direction while sliding in the radial direction. Here, the operation region includes a portion in which the engagement projection of the input gear slides in the radial direction with respect to the engagement recess of the oldham coupling. In addition, in the circumferential direction of the operation region, the input gear and the output gear disposed inside the engagement recess portion mesh to form a meshing portion. In this case, the operation area of the engagement recess of the oldham coupling and the engagement projection of the input gear includes at least the meshing portion of the input gear and the output gear.

Therefore, in this configuration, the opening of the front plate is formed so as to face a region larger than the operation region of the engagement recess of the oldham coupling and the engagement projection of the input gear. In this way, in the valve timing control device, the lubricating oil that lubricates the sliding portions that are close to the engagement concave portion of the oldham coupling and the engagement protrusion of the input gear can be discharged to the outside from the opening of the front plate early. Further, if the opening is larger than the operation area of the engagement concave portion of the oldham coupling and the engagement protrusion of the input gear, the opening of the front plate may be opposed not only to the sliding portion of the engagement concave portion of the oldham coupling and the engagement protrusion of the input gear but also to the meshing portion of the input gear and the output gear. Therefore, in the case of the present configuration, the valve timing control device can discharge both the lubricating oil that lubricates the radial sliding portion existing in the vicinity of the operation region of the engagement recess of the oldham coupling and the engagement projection of the input gear and the lubricating oil that lubricates the circumferential sliding portion from the opening of the front plate to the outside.

A further feature of the valve timing control apparatus according to the present invention is that: the openings are provided in plural at equal intervals in the circumferential direction of the front plate.

According to the above configuration, since the front plate has the plurality of openings, the valve timing control apparatus can efficiently discharge the lubricating oil that lubricates the sliding portion inside the apparatus to the outside from the plurality of openings of the front plate. Further, by arranging the plurality of openings at appropriate positions at equal intervals in the circumferential direction of the front plate, the area of each of the openings in the front plate can be reduced.

Drawings

Fig. 1 is a sectional view of a valve timing control apparatus.

FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1.

Fig. 3 is a cross-sectional view taken along line iii-iii of fig. 1.

FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 1.

Fig. 5 is a cross-sectional view taken along line v-v of fig. 1.

Fig. 6 is a main part front view of the portion K of fig. 5 enlarged.

Fig. 7 is an exploded perspective view of the valve timing control apparatus.

Fig. 8 is a front view of a main portion of a valve timing control apparatus according to another embodiment.

Fig. 9 is a front view of a main portion of a valve timing control apparatus of another embodiment.

Fig. 10 is a partial front view of a valve timing control apparatus of another embodiment.

Fig. 11 is a front view of a main portion of a valve timing control apparatus according to another embodiment.

Detailed Description

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

Basic structure

As shown in fig. 1, the valve timing control apparatus 100 according to the present embodiment includes a driving-side rotating body a that rotates in synchronization with a crankshaft 1 of an engine E that is an internal combustion engine, an intake camshaft 2 (an example of a valve), a driven-side rotating body B that opens or closes an intake valve 2B (an example of a valve), and a phase adjustment mechanism C that rotates integrally with the intake camshaft 2 about a rotation axis X, and that sets a relative rotation phase of the driving-side rotating body a and the driven-side rotating body B by a driving force of a phase control motor M.

The engine E is configured such that pistons 4 are accommodated in a plurality of cylinders 3 formed in a cylinder block, and the pistons 4 are coupled to a four-stroke type crankshaft 1 via connecting rods 5. The timing chain 6 (may be a timing belt or the like) is wound around the output sprocket 1S of the crankshaft 1 of the engine E and the drive sprocket 11S of the drive-side rotating body a.

Thus, when the engine E is operated, the valve timing control apparatus 100 rotates around the rotation axis X as a whole. Further, the phase adjustment mechanism C is operated by the driving force of the phase control motor M, so that the driven-side rotating body B can be displaced in the same direction as or in the opposite direction to the rotation direction with respect to the driving-side rotating body a. The relative rotational phase of the driving side rotor a and the driven side rotor B is set by the displacement by the phase adjustment mechanism C, so that the cam portion 2A of the intake camshaft 2 controls the opening and closing timing (opening and closing time) of the intake valve 2B.

The operation of relatively displacing the driven-side rotary body B in the same direction as the rotation direction of the driving-side rotary body a is referred to as an advance operation, and the intake compression ratio increases by the advance operation. The operation of relatively displacing the driven-side rotating body B in the direction opposite to the driving-side rotating body a (the operation in the direction opposite to the advance angle operation) is referred to as a retard angle operation, and the intake air compression ratio is reduced by this retard angle operation.

[ valve timing control apparatus ]

As shown in fig. 1, a casing 11 having a drive sprocket 11S formed on the outer periphery thereof is fastened to a front plate 12 by a plurality of fastening bolts 13 to construct a drive-side rotating body a. The housing 11 has a bottomed tubular structure having an opening at the bottom.

As shown in fig. 1 to 5, an intermediate member 20 (see fig. 2, etc.) as a driven-side rotating body B, and a phase adjustment mechanism C (see fig. 3, etc.) having an in-circle trochoid gear reduction mechanism are housed in the inner space of the housing 11. The phase adjustment mechanism C includes an oldham coupling Cx (see fig. 4, etc.) in which a phase change is reflected on the driving-side rotating body a and the driven-side rotating body B.

The intermediate member 20 constituting the driven-side rotating body B is integrally formed with a support wall portion 21 and a cylindrical wall portion 22, the support wall portion 21 being coupled to the intake camshaft 2 in a posture orthogonal to the rotation axis X, the cylindrical wall portion 22 being cylindrical centered on the rotation axis X and protruding from an outer peripheral edge of the support wall portion 21 in a direction away from the intake camshaft 2.

The intermediate member 20 is fitted in a relatively rotatable manner in a state where the outer surface of the cylindrical wall portion 22 is in contact with the inner surface of the housing 11, and is fixed to the end portion of the intake camshaft 2 by a coupling bolt 23 inserted into a through hole in the center of the support wall portion 21. In the thus fixed state, the end of the outer side (the side farther from the intake camshaft 2) of the cylindrical wall portion 22 is located further to the inner side than the front plate 12.

As shown in fig. 1 and 7, a groove 22a is formed on the outer peripheral side of the cylindrical wall 22 over the entire periphery. The groove portion 22a improves the retention of oil between the outer surface of the cylindrical wall portion 22 and the inner surface of the housing 11. Thereby, the friction force between the cylindrical wall 22 and the housing 11 is reduced, and the intermediate member 20 rotates smoothly with respect to the housing 11.

As shown in fig. 1, the phase control motor M is supported by the support frame 7 so that the output shaft Ma thereof is disposed on the same axis as the rotation axis X. A pair of engagement pins 8 (see also fig. 3 to 5) are formed on the output shaft Ma of the phase control motor M in a posture orthogonal to the rotation axis X.

[ phase adjustment mechanism ]

As shown in fig. 1 and 7, the phase adjustment mechanism C includes an intermediate member 20, an output gear 25 formed on an inner peripheral surface of a cylindrical wall portion 22 of the intermediate member 20, an eccentric member 26, an elastic member S, a first bearing 28, a second bearing 29 (an example of a "support bearing"), an input gear 30, a fixed ring 31, an annular packing 32, and an oldham coupling Cx. The first bearing 28 and the second bearing 29 are rolling bearings, but sliding bearings may be used. In the present embodiment, the second bearing 29 is a ball bearing having an inner ring 29a attached to the eccentric member 26 and an outer ring 29b attached to the input gear 30.

As shown in fig. 1, a support surface 22S centered on the rotation axis X is formed on the inner periphery of the cylindrical wall portion 22 of the intermediate member 20 along the inner side (a position adjacent to the support wall portion 21) in the direction of the rotation axis X (hereinafter, referred to as an axial direction), and an output gear 25 centered on the rotation axis X is integrally formed on the outer side (a side farther from the intake camshaft 2) of the support surface 22S.

As shown in fig. 1, 2 and 7, the eccentric member 26 has a cylindrical shape. The eccentric member 26 has a circumferential support surface 26S formed on an axially inner side (a side closer to the intake camshaft 2) of an outer circumferential surface centered on the rotation axis X. As shown in fig. 1, 3 and 7, the eccentric member 26 is formed with an eccentric bearing surface 26E on the outer side (the side farther from the intake camshaft 2) of the outer peripheral surface centered on an eccentric axis Y that is eccentric in a posture parallel to the rotation axis X. Since the direction along the eccentric axis Y is the same as the axial direction, the direction along the eccentric axis Y will hereinafter be simply referred to as the axial direction.

As shown in fig. 4, 5, and 7, a first concave portion 70 recessed inward in the radial direction of the eccentric member 26 is formed in the eccentric bearing surface 26E. In the bottom surface of the first concave portion 70, a pair of second concave portions 79,79 recessed toward the radial axis side of the eccentric member 26 are formed at both ends in the circumferential direction of the eccentric member 26. In the present embodiment, the first concave portion 70 is symmetrical in the circumferential direction (left-right symmetry in fig. 4 and 5).

Second recesses 79,79 are formed at respective ends in the circumferential direction of the eccentric member 26 in the first recess 70, respectively. The maximum depth of the bottom surfaces of the second recesses 79,79 in the radial direction of the eccentric member 26 is larger than the depth of the bottom surface near the circumferential center of the eccentric member 26 in the first recess 70. The surfaces of the second recesses 79,79 in the circumferential direction of the eccentric member 26 from the bottom surface to the end portion each have a shape along the curved shape of the spring member 71 described later.

The first recess 70 has an elastic member S embedded therein. The elastic member S includes a pair of spring members 71,71. In the present embodiment, the pair of spring members 71,71 each have the same shape and size. The elastic member S applies a force to the input gear 30 through the second bearing 29 so that a part of the external teeth portion 30A of the input gear 30 meshes with a part of the internal teeth portion 25A of the output gear 25. This prevents the expansion of the backlash between the input gear 30 and the output gear 25, thereby preventing abnormal sounds. In addition, the durability of the input gear 30 and the output gear 25 can be improved.

As shown in fig. 1 and 7, a pair of engagement grooves 26T are formed in the inner periphery of the eccentric member 26 in a parallel posture with the rotation axis X, and a pair of engagement pins 8 of the phase control motor M (see fig. 1) can be engaged with the pair of engagement grooves 26T, respectively. Further, a plurality of first oil grooves 26a (see fig. 1) are formed in a radial posture on the inner side (support wall portion 21 side) of the eccentric member 26, and a plurality of second oil grooves 26b are formed in a radial posture on the outer side (side farther from the intake camshaft 2). It should be noted that only one of the first oil groove 26a and the second oil groove 26b may be formed in the eccentric member 26. The number of these first oil grooves 26a and second oil grooves 26b may be arbitrarily set.

As shown in fig. 7, on the inner peripheral side of the opening end of the outer side (the side farther from the intake camshaft 2) of the eccentric member 26, tapered portions 26c (inclined portions) whose diameter decreases toward the inner side (the side nearer to the intake camshaft 2) are formed on both side portions of the engagement groove 26T. When the pair of engagement pins 8 of the phase control motor M are engaged with the engagement grooves 26T of the eccentric member 26, the engagement pins 8 are guided to the engagement grooves 26T by the tapered portions 26c, so that the engagement operation of the phase control motor M with the eccentric member 26 is easy.

As shown in fig. 1 and 2, the eccentric member 26 is rotatably supported about the rotation axis X with respect to the intermediate member 20 by fitting the first bearing 28 to the circumferential support surface 26S and fitting the first bearing 28 to the support surface 22S of the cylindrical wall portion 22. As shown in fig. 1 and 3, the input gear 30 is rotatably supported about the eccentric axis Y with respect to the eccentric support surface 26E of the eccentric member 26 via the second bearing 29.

In this phase adjustment mechanism C, the number of teeth of the external gear portion 30A of the input gear 30 is set to be 1 tooth less than the number of teeth of the internal gear portion 25A of the output gear 25. Further, a part of the external gear portion 30A of the input gear 30 meshes with a part of the internal gear portion 25A of the output gear 25.

As shown in fig. 1 and 7, the fixing ring 31 is supported on the outer periphery of the eccentric member 26 in a fitted state, thereby preventing the second bearing 29 from coming off.

[ phase adjustment mechanism: oldham coupling

As shown in fig. 1, 4, and 7, the oldham coupling Cx is constituted by a plate-shaped coupling member 40, and the coupling member 40 is integrally formed with a central annular portion 41, a pair of outer engagement arms 42 protruding radially outward from the annular portion 41 in a first direction (left-right direction in fig. 4), and an inner engagement arm 43 protruding radially outward from the annular portion 41 in a direction orthogonal to the first direction (up-down direction in fig. 4). Each of the pair of inner engaging arms 43 is formed with an engaging recess 43a connected to the opening of the annular portion 41.

In the case 11, a pair of guide groove portions 11a are formed at the opening edge portion where the front plate 12 is abutted, and the pair of guide groove portions 11a are formed in a through groove shape so as to extend radially upward around the rotation axis X across from the inner space to the outer space of the case 11. The guide groove 11a has a groove width set to be slightly wider than the width of the outer engagement arm 42, and a pair of discharge passages 11b are formed in each guide groove 11a so as to form a notch. The discharge flow path 11b may be formed so as to flow lubricating oil in the radial direction with respect to the front plate 12.

In the opening edge portion of the housing 11, one or more grooves (pockets) 11c are formed by forming notches in the inner peripheral side in the circumferential direction at positions other than the guide groove portion 11 a. Foreign matter that moves to the outer peripheral side by the centrifugal force generated by the rotation of the driving-side rotating body a is collected in the groove portion 11c. Fig. 7 shows a case where 4 groove portions 11c are formed.

Further, a pair of engaging projections 30T are integrally formed on an end surface of the input gear 30 facing the front plate 12. The engagement width of the engagement projection 30T is set to be slightly smaller than the engagement width of the engagement recess 43a of the inner engagement arm 43.

According to such a configuration, the oldham coupling Cx can be operated by engaging the pair of outer engaging arms 42 of the coupling member 40 with the pair of guide groove portions 11a of the housing 11, and engaging the pair of engaging projections 30T of the input gear 30 with the engaging recesses 43a of the pair of inner engaging arms 43 of the coupling member 40.

The coupling member 40 is displaceable with respect to the housing 11 in a first direction (left-right direction in fig. 4) in which the outer engagement arm 42 extends, and the input gear 30 is displaceable with respect to the coupling member 40 in a second direction (up-down direction in fig. 4) along a direction in which the engagement recess 43a of the inner engagement arm 43 is formed.

As shown in fig. 1 and 7, the spacer 32 makes the distance of the gap in which the second bearing 29 is movable in the axial direction equal to or smaller than a predetermined set value. By providing the spacer 32 between the oldham coupling Cx (coupling member 40) and the second bearing 29, the movement of the second bearing 29 in the axial direction is restricted to a distance equal to or less than a predetermined set value. Thereby, the engagement protrusion 30T of the input gear 30 can be prevented from contacting the front plate 12.

[ arrangement of the respective portions of the valve timing control apparatus ]

As shown in fig. 1, in the valve timing control apparatus 100 in the assembled state, the support wall portion 21 of the intermediate member 20 is coupled to the end portion of the intake camshaft 2 by the coupling bolt 23, and they are integrally rotated. The eccentric member 26 is supported by the first bearing 28 so as to be rotatable about the rotation axis X with respect to the intermediate member 20. As shown in fig. 1 and 3, the input gear 30 is supported by the second bearing 29 against the eccentric support surface 26E of the eccentric member 26, and a part of the external teeth portion 30A of the input gear 30 meshes with a part of the internal teeth portion 25A of the output gear 25.

As shown in fig. 4, the outer engagement arm 42 of the oldham coupling Cx is engaged with the pair of guide groove portions 11a of the housing 11, and the engagement projection 30T of the input gear 30 is engaged with the engagement recess 43a of the inner engagement arm 43 of the oldham coupling Cx. As shown in fig. 1, since the front plate 12 is disposed outside the coupling member 40 of the oldham coupling Cx, the coupling member 40 can move in a direction perpendicular to the rotation axis X while being in contact with the inner surface of the front plate 12. According to this arrangement, the oldham coupling Cx is disposed at a position outside (on the side farther from the intake camshaft 2) and inside (on the side closer to the intake camshaft 2) the front plate 12 of both the first bearing 28 and the second bearing 29.

As shown in fig. 1 to 3, a pair of engagement pins 8 formed on the output shaft Ma of the phase control motor M are engaged with the engagement grooves 26T of the eccentric member 26.

[ mode of operation of phase adjustment mechanism ]

Although not shown in the drawings, the phase control motor M is controlled by a control device configured as an ECU. The engine E includes sensors capable of detecting rotational speeds (revolutions per unit time) of the crankshaft 1 and the intake camshaft 2 and rotational phases of the respective sensors, and is configured to input detection signals of the sensors to a control device.

The control device drives the phase control motor M at a speed equal to the rotational speed of the intake camshaft 2 when the engine E is running, thereby maintaining the relative rotational phase. In contrast, the phase control motor M is rotated at a lower rotational speed than the intake camshaft 2 to perform the advance operation, whereas the rotational speed is increased to perform the retard operation. As described above, the intake air compression ratio increases due to the advanced angle operation, and decreases due to the retarded angle operation.

When the phase control motor M rotates at the same speed as the housing 11 (the same speed as the intake camshaft 2), the position of the meshing portion of the external teeth portion 30A of the input gear 30 with respect to the internal teeth portion 25A of the output gear 25 does not change, and therefore the relative rotational phase of the driven-side rotating body B with respect to the driving-side rotating body a is maintained.

In contrast, by driving the output shaft Ma of the phase control motor M to rotate at a speed higher or lower than the rotational speed of the housing 11, the eccentric axis Y revolves around the rotation axis X in the phase adjustment mechanism C. Due to this revolution, the position of the meshing portion of the external tooth portion 30A of the input gear 30 with respect to the internal tooth portion 25A of the output gear 25 follows the inner Zhou Bianwei of the output gear 25, and a rotational force acts between the input gear 30 and the output gear 25. That is, a rotational force about the rotation axis X acts on the output gear 25, and a rotational force about the eccentric axis Y acts on the input gear 30 to rotate the same.

As described above, since the engagement protrusion 30T of the input gear 30 is engaged with the engagement recess 43a of the inner engagement arm 43 of the coupling member 40, the input gear 30 does not rotate relative to the housing 11, and the rotational force acts on the output gear 25. By the action of the rotational force, the intermediate member 20 rotates together with the output gear 25 about the rotation axis X with respect to the housing 11. As a result, the relative rotational phases of the driving-side rotating body a and the driven-side rotating body B are set, thereby realizing the setting based on the opening/closing timing of the intake camshaft 2.

When the eccentric axis Y of the input gear 30 revolves around the rotation axis X, the coupling member 40 of the oldham coupling Cx is displaced with respect to the housing 11 in the direction in which the outer engagement arm 42 extends (first direction), and the input gear 30 is displaced in the direction in which the inner engagement arm 43 extends (second direction).

As described above, since the number of teeth of the external gear portion 30A of the input gear 30 is set to be 1 tooth less than the number of teeth of the internal gear portion 25A of the output gear 25, when the eccentric axial center Y of the input gear 30 revolves around the rotation axial center X for only 1 revolution, the output gear 25 rotates for only 1 tooth, and a large reduction is achieved.

[ lubrication of phase adjustment mechanism ]

As shown in fig. 1, a lubrication oil passage 15 is formed in the intake camshaft 2 to supply lubricating oil from an external oil pump P via an oil passage forming member 9. A supply oil passage 21a that guides the oil flowing through the lubrication oil passage 15 to the inside of the eccentric member 26 is formed in a portion of the support wall portion 21 of the intermediate member 20 that abuts on the intake camshaft 2. That is, the support wall portion 21 has a supply oil passage 21a that can supply lubricating oil from the outside to the inside of the driven-side rotating body B.

As described above, the eccentric member 26 is formed with the plurality of first oil grooves 26a and the plurality of second oil grooves 26b (see fig. 1 and 7).

According to the above configuration, the lubricating oil supplied from the oil pump P is supplied from the lubricating oil passage 15 of the intake camshaft 2 to the inner space of the eccentric member 26 via the supply oil passage 21a of the support wall portion 21 of the intermediate member 20. The lubricating oil thus supplied is supplied from the first lubricating oil groove 26a of the eccentric member 26 to the first bearing 28 by centrifugal force, so that the first bearing 28 operates (slides) smoothly. The lubricating oil supplied to the first bearing 28 is then supplied to the adjacent second bearing 29, and is supplied between the internal tooth portion 25A of the output gear 25 and the external tooth portion 30A of the input gear 30, which are disposed on the outer peripheral side of the second bearing 29 and urged by the elastic member S, so that these portions (particularly the meshing portions) work (slide) smoothly.

At the same time, a part of the lubricating oil in the internal space of the eccentric member 26 is supplied from the second lubricating oil groove 26b to the coupling member 40 by centrifugal force, and is supplied to the second bearing 29 and between the internal tooth portion 25A of the output gear 25 and the external tooth portion 30A of the input gear 30.

Further, as shown in fig. 1, the lubricating oil from the second lubricating oil groove 26b is supplied between the front plate 12 and the coupling member 40, and is supplied to the gap between the outer engagement arm 42 of the coupling member 40 and the guide groove portion 11a of the housing 11. This allows the coupling member 40 to operate smoothly.

As described above, the pair of discharge flow paths 11b are formed in the guide groove portion 11a (see fig. 4 and 7). Therefore, the lubricating oil supplied to the coupling member 40 is discharged to the outside from the gap between the outer engagement arm 42 of the coupling member 40 and the guide groove portion 11a of the housing 11. Further, since the discharge flow path 11b is formed in the guide groove portion 11a, the internal lubricating oil can be discharged from the discharge flow path 11b by centrifugal force when the engine E is started.

As shown in fig. 1, 5, and 7, the front plate 12 has a circular first opening 12a centered on the rotation axis X. By setting the opening diameter of the first opening 12a to be larger than the inner diameter of the eccentric member 26, a tomographic difference G is formed between the opening edge of the first opening 12a of the front plate 12 and the inner periphery of the eccentric member 26.

By this difference G, when the engine E is stopped, the lubricant in the internal space of the eccentric member 26 can be discharged from the first opening 12a of the front plate 12, and the amount of lubricant remaining in the interior can be reduced.

In this way, in the valve timing control apparatus 100, the lubricating oil supplied to the inside of the driven-side rotating body B can be discharged from the guide groove portion 11a of the housing 11 and the first opening 12a of the front plate 12. However, in the device, for example, the lubricant supplied to the sliding portion such as the meshing portion of the input gear 30 and the output gear 25 is difficult to be discharged to the outside from the guide groove portion 11a of the housing 11 and the first opening 12a of the front plate 12. In particular, in a cold environment where the viscosity of the lubricating oil increases, the shearing resistance of the lubricating oil retained in the device increases. In addition, in the valve timing control apparatus 100, abrasion powder or foreign matter may be mixed in the lubricating oil at the sliding portion. In this case, abrasion powder or foreign matter that has accumulated in the device together with the lubricating oil may accelerate abrasion of the gear portion or the like. Accordingly, it is desirable that the lubricant oil supplied to the sliding portion inside the device can be discharged to the outside early without stagnation.

Therefore, in the present embodiment, as shown in fig. 5 to 7, a second opening 12b (an example of an "opening" in the present application) is formed in the front plate 12, which is continuous with the first opening 12a and extends radially outward. In the present embodiment, two (a pair of) second openings 12b are formed so as to face the pair of inner engagement arms 43 of the coupling member 40, respectively.

The second opening 12b is formed at a portion at least opposite to a part of the input gear 30, and is provided for discharging the lubricating oil supplied to the sliding portion to the outside. Here, at least a portion facing a part of the input gear 30 is a portion exposed along a part of the circumferential direction of the external tooth portion 30A formed on the outer edge of the input gear 30. The sliding portion is a portion of a member disposed inside the driven-side rotating body B, and is a portion where sliding occurs when the valve timing control apparatus 100 is operated. For example, the engagement recess 43a of the oldham coupling Cx and the engagement projection 30T of the input gear 30 described later slide in the radial direction, and the engagement portion between the input gear 30 and the output gear 25 are equivalent. The oldham coupling Cx included in the phase adjustment mechanism C is displaced in the radial direction around the rotation axis X by the influence of the displacement of the input gear 30, and in this case, the engagement concave portion 43a of the inner engagement arm 43 slides with respect to the engagement protrusion 30T of the input gear 30, thereby generating abrasion powder. Therefore, in the present embodiment, the second opening 12b of the front plate 12 is formed so as to face the entire region R1 of the region R1 in which the engagement protrusion 30T of the input gear 30 slides in the radial direction with respect to the engagement recess 43a of the oldham coupling Cx. The region R1 is, for example, a region between the 1 st position 43a1 on the radially outer side and the 2 nd position 43a2 on the radially inner side of the engagement concave portion 43a shown in fig. 6.

The second opening 12b of the front plate 12 is formed so as to face the meshing portion of the input gear 30 and the output gear 25, which is a sliding portion, on the inner side of the engagement recess 43a of the oldham coupling Cx. Specifically, as shown in fig. 6, the second opening 12b is formed so as to oppose a region R2 that spans from the tooth root 30Aa of the external gear portion 30A of the input gear 30 to the tooth root 25Aa of the internal gear portion 25A of the output gear 25.

In this way, since the front plate 12 has the second opening 12B for discharging the lubricant oil supplied to the driven-side rotating body B to the outside at the portion facing the part of the input gear 30, the valve timing control apparatus 100 can early discharge the lubricant oil for lubricating the sliding portion in the vicinity of the input gear 30 from the second opening 12B to the outside. Further, in the valve timing control apparatus 100, since the second opening 12b of the front plate 12 is provided near the sliding portion, even if abrasion powder or foreign matter is mixed in the lubricating oil that lubricates the sliding portion, or abrasion powder or foreign matter is generated in the sliding portion due to sliding, these abrasion powder or foreign matter can be discharged to the outside together with the lubricating oil from the second opening 12 b. As a result, abrasion in the device other than the sliding portion due to the mixing of abrasion powder and foreign matter into the lubricating oil can be suppressed. Further, since the lubricant oil that lubricates the sliding portion is easily discharged to the outside from the second opening 12b of the front plate 12, the lubricant oil does not remain around the sliding portion, and therefore, the responsiveness of the valve timing control apparatus 100 can be improved even in a cold environment in which the viscosity of the lubricant oil is high.

Further, the second opening 12b of the front plate 12 is formed so as to oppose the entire region of the region R1 in which the engagement recess 43a of the oldham coupling Cx and the engagement projection 30T of the input gear 30 slide in the radial direction. As a result, in the valve timing control apparatus 100, the lubricating oil that lubricates the sliding portions between the engagement concave portion 43a of the oldham coupling Cx and the engagement projection 30T of the input gear 30 can be discharged to the outside from the second opening 12b of the front plate 12 early.

The second opening 12b of the front plate 12 is formed so as to face a region R2, and the region R2 is a region extending from the tooth root 30Aa of the external tooth portion 30A of the input gear 30 to the tooth root 25Aa of the internal tooth portion 25A of the output gear 25 in the meshing portion of the input gear 30 and the output gear 25 inside the engagement recess 43a of the oldham coupling Cx. Thus, in the valve timing control apparatus 100, even if abrasion powder or foreign matter is generated due to sliding in the meshing portion of the input gear 30 and the output gear 25, they can be discharged to the outside from the second opening 12b of the front plate 12 together with the lubricating oil early.

In the present embodiment, as shown in fig. 5, the second openings 12b of the front plate 12 are formed in a pair so as to be opposed to the pair of inner engagement arms 43 of the coupling member 40, respectively. The external tooth portion 30A and the internal tooth portion 25A disposed inside the pair of engagement concave portions 43a,43a and facing the pair of second openings 12b,12b of the front plate 12 are formed in a state in which one side (for example, the upper side in fig. 5) is engaged and the other side (for example, the lower side in fig. 5) is separated. At this time, the gap between the external tooth portion 30A and the internal tooth portion 25A on the other side (lower side) of the separation is formed to be negative pressure compared to the outside, and the gap between the external tooth portion 30A and the internal tooth portion 25A on the one side (upper side) of the engagement is formed to be positive pressure compared to the outside. That is, by providing the pair of second openings 12B,12B corresponding to the pair of engaging concave portions 43a, it is possible to suck the lubricating oil from the gap between the external tooth portion 30A and the internal tooth portion 25A on the other side (lower side) that are separated, and to discharge the lubricating oil to the outside from the gap between the external tooth portion 30A and the internal tooth portion 25A on the one side that are engaged (upper side), so that the internal space of the driven-side rotating body B can function as a kind of pump. Accordingly, the lubricating oil supplied to the meshing portion between the input gear 30 and the output gear 25 can be rapidly discharged to the outside inside the engagement recess 43a of the oldham coupling Cx. The second openings 12b may be formed not in a pair but only on one side (upper side) of the external teeth portion 30A engaged with the internal teeth portion 25A, which generates positive pressure and can discharge the lubricating oil to the outside.

As shown in fig. 7, a convex portion 12c protruding inward is formed on the inner side (side closer to the intake camshaft 2) surface of the front plate 12. The convex portion 12c lightly abuts against the intermediate member 20 so as to be slidably contacted therewith. The intermediate member 20 is brought into contact with the projection 12c to restrict movement thereof toward the front plate 12 side. Thus, the oldham coupling Cx (coupling member 40) can be operated smoothly (smoothly) while maintaining a predetermined distance between the front plate 12 and the intermediate member 20.

The eccentric member 26 is supported by the first bearing 28 on the inner circumferential support surface 22S of the intermediate member 20, and the input gear 30 is supported by the second bearing 29 on the eccentric support surface 26E of the eccentric member 26. Therefore, even if the biasing force of the elastic member S acts in the direction of changing the posture of the eccentric member 26, the entire circumference of the outer surface of the circumferential support surface 26S of the eccentric member 26 is held so as to be enclosed in the inner circumference of the intermediate member 20 by the first bearing 28, so that the positional relationship between the eccentric member 26 and the intermediate member 20 can be maintained.

In this configuration, since the biasing force of the elastic member S acts only between the eccentric member 26 and the intermediate member 20 and does not act on the external member, it is possible to maintain the posture of the eccentric member 26 with higher accuracy without taking into consideration, for example, the deformation and displacement of the external member with respect to the biasing force of the elastic member S.

Further, by forming the first oil groove 26a and the second oil groove 26b for flowing the lubricating oil at the end portion of the eccentric member 26, the oldham coupling Cx is smoothly operated, the first bearing 28 and the second bearing 29 are smoothly operated, the internal tooth portion 25A of the output gear 25 and the external tooth portion 30A of the input gear 30 are smoothly engaged, and the load acting on the phase control motor M is reduced. By forming the first oil groove 26a and the second oil groove 26b in this way, the lubricating oil is supplied to the portion where the lubricating oil is required, so that the lubricating oil is not wasted and the amount of lubricating oil can be reduced.

In particular, by supplying the lubricating oil between the coupling member 40 and the front plate 12 that constitute the oldham coupling Cx, the operation of the coupling member 40 is smoothly performed, and the load acting on the phase control motor M can be further reduced.

Second embodiment

In the second embodiment, as shown in fig. 8, the second opening 12b of the front plate 12 is formed as a separate opening spaced from the first opening 12 a. Specifically, in the front plate 12, the second opening 12b is not connected to the first opening 12a, and an intermediate region 12d exists between the first opening 12a and the second opening 12 b. The second opening 12b has a pair of opening portions 12b1,12b1 provided extending in the radial direction and an opening portion 12b2 provided extending in the circumferential direction. The pair of opening portions 12b1,12b1 are provided in the front plate 12 so as to extend in the radial direction of the engagement concave portion 43a, and are formed so as to oppose the entire region R1 where the inner engagement arm 43 of the oldham coupling Cx slides with the engagement projection 30T of the input gear 30. The opening portion 12b2 connects radially outer sides of the pair of opening portions 12b1, and is formed so as to oppose a region spanning from the root 30Aa of the external tooth portion 30A of the input gear 30 to the root 25Aa of the internal tooth portion 25A of the output gear 25 in the meshing portion of the input gear 30 and the output gear 25. Thus, the second opening 12b is formed in a U-shape as a whole, and the area of the second opening 12b is smaller than that of the first embodiment, but the same operational effects as those of the first embodiment can be exhibited.

Third embodiment

In the third embodiment, as shown in fig. 9, in the front plate 12, the second opening 12b is formed so as to face the entire region R1 where the engagement concave portion 43a of the inner engagement arm 43 of the oldham coupling Cx slides with the engagement protrusion 30T of the input gear 30. Specifically, the second opening 12b is constituted by a pair of opening portions 12b1,12b1 connected to the first opening 12a and provided to extend in the radial direction (the extending direction of the region R1). Therefore, in the third embodiment, the area of the second opening 12b of the front plate 12 for discharging abrasion powder and foreign matter to the outside is smaller than in the above-described embodiment, but the same operational effects as in the above-described embodiment can be exhibited. Specifically, the lubricating oil supplied to the region where the engagement concave portion 43a of the oldham coupling Cx and the engagement projection 30T of the input gear 30 slide can be mainly discharged.

Fourth embodiment

In the fourth embodiment, as shown in fig. 10, in the front plate 12, the second opening 12b is formed as a region facing the circumferential outside of the engagement concave portion 43a of the inner engagement arm 43 as the oldham coupling Cx, and the external tooth portion 30A is opposed to the meshing portion of the internal tooth portion 25A. Specifically, a plurality of rectangular second openings 12b (in the present embodiment, one on each side of the inner engagement arm 43) are formed in the circumferential direction with respect to the rotation axis X along the circumferential direction of the inner engagement arm 43. The second opening 12b is constituted by an opening portion 12b2 opposed to a region R2, which is a region spanning from the tooth root 30Aa of the external tooth portion 30A of the input gear 30 to the tooth root 25Aa of the internal tooth portion 25A of the output gear 25 in the meshing portion of the input gear 30 and the output gear 25. Therefore, in the fourth embodiment, the second opening 12b of the front plate 12 can mainly discharge the lubricating oil supplied to the region where the input gear 30 and the output gear 25 mesh, which is the outer region of the inner engagement arm 43 of the oldham coupling Cx.

Fifth embodiment

In the valve timing control apparatus 100, the oldham coupling Cx of the phase adjustment mechanism C is displaced in the radial direction around the rotation axis X by the influence of the displacement of the input gear 30. Therefore, the engagement concave portion 43a of the oldham coupling Cx and the engagement protrusion 30T of the input gear 30 have an operation region (regions R3 and R4 in fig. 11) that slides in the radial direction and moves in the circumferential direction. Here, the region R3 is a region in which the engagement concave portion 43a and the engagement protrusion 30T move in the circumferential direction as the oldham coupling Cx is displaced in the direction in which the outer engagement arm 42 extends (first direction). Further, the region R4 is a region in which the engaging protrusion 30T moves in the radial direction with respect to the engaging concave portion 43 a. Therefore, the radial region R4 is the same as the region R1 in which the engagement protrusion 30T of the input gear 30 slides in the radial direction with respect to the engagement recess 43a of the oldham coupling Cx. The region R3 is a portion where the input gear 30 and the output gear 25 mesh with each other inside the engagement recess 43 a.

Therefore, in the fifth embodiment, as shown in fig. 11, the second opening 12b of the front plate 12 is formed so as to face a region larger than the operation region (region R3 and region R4) of the engagement recess 43a of the oldham coupling Cx and the engagement projection 30T of the input gear 30. As a result, in the valve timing control apparatus 100, the lubricating oil that lubricates the sliding portion between the engagement concave portion 43a near the oldham coupling Cx and the engagement projection 30T of the input gear 30 can be discharged to the outside from the second opening 12b of the front plate 12 early.

If the second opening 12b of the front plate 12 is larger than the operation region (region R3 and region R4), the second opening 12b of the front plate 12 may be opposed to the engagement portion of the engagement recess 43a of the oldham coupling Cx and the engagement projection 30T of the input gear 30, or the engagement portion of the input gear 30 and the output gear 25. Therefore, the valve timing control apparatus 100 can early discharge both the lubricating oil for lubricating the sliding portions in the radial direction and the lubricating oil for lubricating the sliding portions in the circumferential direction to the outside from the second opening 12b of the front plate 12 in the vicinity of the operation region of the engagement recess 43a of the oldham coupling Cx and the engagement projection 30T of the input gear 30.

Other embodiments

(1) The number of the second openings 12b formed in the front plate 12 may be 1 or more. By providing the plurality of second openings 12b in the front plate 12, the lubricant can be more efficiently discharged from the second openings 12b to the outside. Further, by dispersing the plurality of second openings 12b in the front plate 12 at appropriate positions, the area of each of the second openings 12b in the front plate 12 can also be reduced. In this case, the plurality of second openings 12b may be arranged at equal intervals in the circumferential direction. The plurality of second openings 12b may be arranged at a position of the oldham coupling Cx where rotation balance is achieved, for example, in the vicinity of the outer engagement arm 42 and the inner engagement arm 43 of the oldham coupling Cx having a mass larger than that of the annular portion 41. The second opening 12b may be provided in both a position facing the inner engagement arm 43 of the oldham coupling Cx and a position facing a region of the outer teeth portion 30A meshing with the inner teeth portion 25A, which is an outer region of the inner engagement arm 43, in the front plate 12.

(2) In the second embodiment, an example in which the second opening 12b spaced from the first opening 12a is formed in a U-shape in the front plate 12 is shown, but the second opening 12b may be formed in a rectangular shape.

(3) In the third embodiment, an example in which the opening portion 12b1 of the second opening 12b is configured to be connected to the first opening 12a in the front plate 12 is shown, but the opening portion 12b1 may be formed to be spaced from the first opening 12 a.

[ Industrial applicability ]

The present invention can be used in a valve timing control apparatus.

Symbol description

1: crankshaft

2: air inlet cam shaft (cam shaft)

2B: air inlet valve (valve)

11: outer casing

12: front plate

12a: a first opening

12b: second opening (opening)

12b1,12b2,12b3: an opening portion

20: intermediate part

21: support wall portion

21a: oil supply path

25: output gear

25A: internal tooth part

25Aa: tooth root

26: eccentric part

28: first bearing

29: second bearing (support bearing)

30: input gear

30A: external tooth part

30Aa: tooth root

40: coupling part

41: annular part

42: external clamping arm

43: internal clamping arm

43a: engagement concave portion

43a1: position 1

43a2: position 2

100: valve timing control device

A: driving side rotator

B: driven side rotator

C: phase adjusting mechanism

Cx: oldham coupling

E: engine (internal combustion engine)

R1, R2: region(s)

R3, R4: action region

S: elastic component

X: rotation axis

Y: eccentric axis.

Claims (5)

1. A valve timing control device is provided with:

a driving-side rotating body that rotates in synchronization with a crankshaft of an internal combustion engine around a rotation axis;

a driven-side rotating body that is coaxial with the rotation shaft center, is disposed inside the driving-side rotating body, and rotates integrally with a camshaft for opening and closing a valve of the internal combustion engine; the method comprises the steps of,

a phase adjustment mechanism that sets a relative rotational phase of the driving-side rotating body and the driven-side rotating body,

the phase adjustment mechanism includes:

an output gear which is coaxially provided with the rotation shaft center and is provided to the driven-side rotation body;

an input gear that rotates around an eccentric axis that is parallel to the rotation axis and is coupled to the driving-side rotating body; the method comprises the steps of,

a cylindrical eccentric member that supports the input gear from an inner peripheral side via a support bearing and rotates the input gear,

The phase adjustment mechanism is configured to revolve the eccentric shaft center by rotation of the eccentric member, thereby changing a position of a meshing portion of the output gear and the input gear,

the driven side rotating body has a support wall portion connected to an end portion of the camshaft in a posture orthogonal to the rotation axis,

the support wall portion has a supply oil passage capable of supplying lubricating oil from the outside to the inside of the driven side rotating body,

the driving side rotating body has a front plate on the opposite side of the cam shaft with respect to the eccentric member in the direction along the rotation axis,

the front plate has an opening for discharging the lubricant oil supplied to the driven-side rotating body to the outside at least in a portion facing a part of the input gear.

2. The valve timing control apparatus according to claim 1, wherein,

the phase adjustment mechanism further has an Oldham coupling,

the oldham coupling has an inner engagement arm protruding radially outward about the rotation axis and an engagement recess formed inside the inner engagement arm,

the input gear has an engagement protrusion, and is coupled to the driving-side rotating body by engagement of the engagement protrusion with the engagement recess of the oldham coupling,

The opening is formed so as to oppose the entire area of the engagement protrusion of the input gear that slides in the radial direction with respect to the engagement recess of the oldham coupling.

3. The valve timing control apparatus according to claim 1 or 2, wherein,

the opening is formed opposite to a region in the meshing portions of the input gear and the output gear that spans from the root of the external tooth portion of the input gear to the root of the internal tooth portion of the output gear.

4. The valve timing control apparatus according to claim 2, wherein,

the opening is formed to be opposed to a larger area than an operation area in which the engagement recess of the oldham coupling and the engagement projection of the input gear move in the circumferential direction while sliding in the radial direction.

5. The valve timing control apparatus according to any one of claims 1 to 4, wherein,

the openings are provided in plurality at equal intervals in the circumferential direction of the front plate.

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