JP7707883B2 - Valve timing control device - Google Patents

Description

The present invention relates to a valve timing control device.

For example, as a valve timing control device that sets the opening and closing timing (valve timing) of the intake valve of an internal combustion engine, Patent Document 1 describes a configuration in which an internally toothed output gear is arranged around a rotation axis, an externally toothed input gear with fewer teeth than the output gear is arranged around an eccentric shaft that is eccentric to the rotation axis, an eccentric member is provided that meshes the external teeth of the input gear with the internal teeth of the output gear, and a motor is provided to drive and rotate the eccentric member.

In the valve timing control device of Patent Document 1, the gear configuration described above is called a hypotrochoid type gear reduction mechanism, and in this gear reduction mechanism, in order to keep the external teeth of the input gear meshed with the internal teeth of the output gear, a spring member is fitted into a recess on the outer peripheral surface of the eccentric member, and the biasing force of this spring member is applied to the inner peripheral side of the input gear.

JP 2021-17833 A

However, the spring plate (spring member) of the configuration described in Patent Document 1 may break over a long period of use, and there is concern that a part of the spring plate that breaks off may fall off the eccentric member and enter between the external teeth of the input gear and the internal teeth of the output gear, or may come into contact with a moving part within the device, disabling the operation of the valve timing control device.

For these reasons, there is a demand for a valve timing control device that will not become inoperable even if the spring body that engages the internal and external teeth of the reduction mechanism breaks.

The characteristic configuration of the valve opening/closing timing control device according to the present invention is a drive-side rotor that rotates synchronously with the crankshaft of an internal combustion engine around a rotation axis, a driven-side rotor that is arranged coaxially with the rotation axis and inside the drive-side rotor and rotates integrally with a camshaft for opening and closing the valves of the internal combustion engine, and a phase adjustment mechanism that adjusts the relative rotation phase of the drive-side rotor and the driven-side rotor, and the phase adjustment mechanism is composed of an internally toothed output gear that rotates integrally with the driven-side rotor around the same axis as the rotation axis, an externally toothed input gear that has fewer teeth than the output gear, is arranged inside the output gear, and rotates around an eccentric axis parallel to the rotation axis, and a relay that links the input gear to the rotation of the drive-side rotor. The eccentric member has a recessed portion that is recessed radially from an eccentric support surface centered on the eccentric shaft and opens toward the end of the eccentric member in a direction along the eccentric shaft. A spring member that applies a biasing force to mesh the external teeth of the input gear with the internal teeth of the output gear is fitted into the recessed portion. A fixing ring is provided on the outer periphery of the eccentric support surface so as to overlap the recessed portion when viewed radially. The fixing ring has a restricting portion that fits into the recessed portion to prevent the spring member from falling off.

According to this characteristic configuration, the spring member is fitted into the concave portion of the eccentric support surface of the eccentric member, so that the urging force of the spring member can be applied in a direction in which the teeth of the input gear mesh with the teeth of the output gear. Also, since the fixing ring has a restricting portion that fits into the concave portion, the spring member will not fall out of the concave portion even under normal use conditions, and even if the spring member breaks due to long-term use, the restricting portion prevents the broken pieces from falling out of the concave portion.
Therefore, a valve timing control device is configured that will not become inoperable even if the spring member for engaging the internal teeth portion and the external teeth portion of the reduction mechanism is broken.

In addition to the above configuration, the eccentric member may have an annular groove on the outer periphery of the eccentric support surface of the eccentric member, and the fixing ring may be fitted into the annular groove.

With this, an annular groove is formed on the outer periphery of the eccentric support surface of the eccentric member, and the fixing ring can be supported by fitting into this annular groove, eliminating the need to provide a separate support means for supporting the fixing ring.

In addition to the above configuration, the spring member may have a curved portion formed by bending a spring plate, a support portion extending one side of the spring plate of the curved portion to contact the bottom surface of the concave portion, a biasing portion extending the other side of the spring plate of the curved portion to apply a biasing force to the inner periphery of the input gear, and a bent portion bent into a position in which the tip side of the support portion is separated from the bottom surface of the concave portion, and the bent portion and the regulating portion may overlap when viewed in a direction along the eccentric axis.

With this, a bent portion is formed at the end of the support portion constituting the spring member, which is oriented away from the bottom surface of the concave portion toward the tip side, so that when viewed in the direction along the eccentric axis, the bent portion overlaps with the restricting portion, and the bent portion comes into contact with the restricting portion, thereby preventing the spring member from falling off the concave portion. Also, with this configuration, the tip of the end of the spring plate material that contacts the concave portion is separated from the bottom surface of the concave portion, which also reduces wear on the bottom surface caused by the tip coming into contact with the bottom surface.

In addition to the above configuration, the gap between the protruding end of the restricting portion of the fixing ring and the bottom surface of the recessed portion when viewed in a direction along the eccentric shaft may be smaller than the thickness of the spring plate material.

This eliminates the inconvenience that, even if the spring member breaks, the broken part of the spring member falls out of the gap between the protruding end of the restricting portion of the fixing ring and the bottom surface of the recessed portion.

In addition to the above configuration, the spring member has a curved portion formed by bending a spring plate, a support portion extending one side of the spring plate at the curved portion to contact the bottom surface of the concave portion, a biasing portion extending the other side of the spring plate at the curved portion to apply a biasing force to the inner circumferential side of the input gear, and a bent portion bent into a position in which the tip side of the support portion is separated from the bottom surface of the concave portion, and the two spring members are fitted into the concave portion so that the respective curved portions face the end faces of both ends in the circumferential direction of the concave portion, and when viewed in a direction along the eccentric axis, When the curved portion of one of the spring members fitted into the recessed portion is in a position that contacts one of the end faces in the circumferential direction of the recessed portion, and the restricting portion of the fixing ring is in a position closest to the other end face in the circumferential direction of the recessed portion, the restricting region length along the circumferential direction from the other end face in the circumferential direction of the recessed portion to the edge of the restricting portion of the fixing ring that is farther from the other end face may be set to be larger than the spring region length along the circumferential direction from the other end face in the circumferential direction of the recessed portion to the bent portion of the other spring member.

When two spring members are combined and fitted into a recessed portion, a curved portion of one of the two spring members contacts one end face of the recessed portion, and the restricting portion of the fixing ring is closest to the other end face of the recessed portion. In this assumption, the length of the restricting region along the circumferential direction from the other end face of the recessed portion to the edge of the restricting portion of the fixing ring farther from the other end face is set to be larger than the length of the spring region along the circumferential direction from the other end face of the recessed portion to the bent portion of the other spring member.
In other words, in this assumption, the restriction area length relative to the spring area length is determined so that the restriction part is positioned to fully overlap one of the spring members in the direction along the eccentric axis when the two spring members and the restriction part are moved to their movement limits in the opposite directions in the concave part. This prevents the spring members from falling off, and also makes it possible to prevent the broken parts from falling off when the spring members break.

FIG. 2 is a cross-sectional view of the valve timing control device. 2 is a cross-sectional view taken along line II-II of FIG. 1. 3 is a cross-sectional view taken along line III-III in FIG. 1. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 2 is an exploded perspective view of the valve timing control device. 13 is a cross-sectional view showing the positional relationship between a recessed portion, a pair of spring members, and a restriction ring. FIG. FIG. 4 is a perspective view showing two spring members that constitute the biasing mechanism. 6 is a cross-sectional view illustrating the plate thickness of a spring member and the protruding amount of a bent portion. FIG. 13A and 13B are diagrams illustrating the relationship between a recessed portion and a restricting portion of a fixing ring. 13A and 13B are diagrams illustrating the dimensional relationship between the two spring members and the restricting portion when they are moved to their respective ends in opposite directions in the recessed portion.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[Basic configuration]
As shown in FIG. 1, the valve opening/closing timing control device 100 according to this embodiment includes a driving rotor A that rotates synchronously with a crankshaft 1 of an engine E as an internal combustion engine, a driven rotor B that rotates integrally with an intake camshaft 2 that opens and closes an intake valve 2B (an example of a valve), and a phase adjustment mechanism C that sets the relative rotational phase between the driving rotor A and the driven rotor B using the driving force of a phase control motor M.

This valve timing control device 100 has a driving rotor A and a driven rotor B that are rotatable relative to each other within a set range around a rotation axis X.

Engine E is a four-stroke engine with pistons 4 housed in multiple cylinders 3 formed in a cylinder block, and the pistons 4 are connected to a crankshaft 1 by connecting rods 5. A timing chain 6 (or a timing belt) is wound around the output sprocket 1S of the crankshaft 1 of engine E and the drive sprocket 11S of the drive-side rotor A.

As a result, when the engine E is running, the entire valve timing control device 100 rotates around the rotation axis X. The phase adjustment mechanism C uses the driving force of the phase control motor M to set the relative rotation phase between the driving rotor A and the driven rotor B, and realizes control of the opening and closing timing (opening and closing timing) of the intake valve 2B by the cam portion 2A of the intake camshaft 2.

In other words, the operation in which the driven rotor B is displaced relatively in the same direction as the driving rotor A is called advance operation, and this advance operation increases the intake compression ratio. On the other hand, the operation in which the driven rotor B is displaced relatively in the opposite direction to the driving rotor A (operation in the opposite direction to advance operation) is called retard operation, and this retard operation reduces the intake compression ratio.

[Valve opening/closing timing control device]
1, the driving-side rotating body A is configured by fastening an outer case 11, which has a driving sprocket 11S formed on its outer periphery, to a front plate 12 with a plurality of fastening bolts 13. The outer case 11 is a cylindrical type with a bottom having an opening at its bottom.

As shown in Figures 1 to 5, the inner space of the outer case 11 contains an intermediate member 20 as the driven rotor B, and a phase adjustment mechanism C (see Figure 3, etc.) with a hypotrochoid type gear reduction mechanism. The phase adjustment mechanism C is equipped with an Oldham coupling Cx (see Figures 4 and 5) that reflects the phase change to the driving rotor A and the driven rotor B.

The intermediate member 20 constituting the driven rotor B is integrally formed with a support wall portion 21 that connects to the intake camshaft 2 in a position perpendicular to the rotation axis X, and a cylindrical wall portion 22 that is cylindrical and centered on the rotation axis X and protrudes in a direction away from the intake camshaft 2.

This intermediate member 20 is fitted into the outer case 11 so as to be relatively rotatable with the outer surface of the cylindrical wall portion 22 in contact with the inner surface of the outer case 11, and is fixed to the end of the intake camshaft 2 by a connecting bolt 23 inserted into a central through hole of the support wall portion 21. In this fixed state, the outer end of the cylindrical wall portion 22 (the side farther from the intake camshaft 2) is located inside the front plate 12.

As shown in Figures 1 and 5, a groove 22a is formed around the entire circumference of the outer periphery of the cylindrical wall 22. The groove 22a improves the oil retention between the outer surface of the cylindrical wall 22 and the inner surface of the outer case 11. This reduces the friction between the cylindrical wall 22 and the outer case 11, allowing the intermediate member 20 to rotate smoothly relative to the outer case 11.

As shown in FIG. 1, the phase control motor M is supported by a support frame 7 on the engine E so that its output shaft Ma is positioned coaxially with the rotation axis X. A pair of engagement pins 8 are formed on the output shaft Ma of the phase control motor M, and are oriented perpendicular to the rotation axis X (see also FIG. 4).

[Phase adjustment mechanism]
1 and 5, the phase adjustment mechanism C includes the intermediate member 20, an output gear 25 formed on the inner circumferential surface of the cylindrical wall portion 22 of the intermediate member 20, an eccentric member 26, a biasing mechanism S, a first bearing 28, a second bearing 29, an input gear 30, a fixed ring 31, a ring-shaped spacer 32, and an Oldham coupling Cx. Note that, although rolling bearings are used for the first bearing 28 and the second bearing 29, plain bearings may also be used.

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

As shown in Figures 1, 2 and 5, the eccentric member 26 is cylindrical. The eccentric member 26 has a circumferential support surface 26S on the outer circumferential surface centered on the rotation axis X on the inside in the axial direction (the side closer to the intake camshaft 2). As shown in Figures 1, 3 and 5, the eccentric member 26 has an eccentric support surface 26E on the outer circumferential surface centered on the eccentric axis Y that is eccentric in a position parallel to the rotation axis X on the outside (the side farther from the intake camshaft 2). The direction along the eccentric axis Y is the same as the axial direction, so hereinafter, the direction along the eccentric axis Y will also be simply referred to as the axial direction.

As shown in Figures 5 and 6, the eccentric support surface 26E has a recessed portion 70 that is recessed radially inward of the eccentric member 26 and opens toward the end direction in the axial direction (outer end direction: toward the front plate 12). This recessed portion 70 has a bottom surface 70a and end surfaces 70b at both ends in the circumferential direction.

As shown in Figures 6 and 9, the bottom surface 70a is formed in a shape in which the central portion in the circumferential direction bulges outward in the radial direction compared to a circular arc surface centered on the eccentric axis Y. Also, as shown in Figures 6 and 8 to 10, the pair of end surfaces 70b are flat when viewed in the direction along the eccentric axis Y, and are formed symmetrically in the circumferential direction.

Two spring members 71 that constitute the biasing mechanism S, as described below, are fitted into the recessed portion 70. The relationship between the recessed portion 70, the bottom surface 70a, and the pair of end surfaces 70b will be described later together with the fixing ring 31, which will be described later.

As shown in Figures 1 and 5, a pair of engagement grooves 26T, which can engage with a pair of engagement pins 8 of the phase control motor M (see Figure 1), are formed on the inner circumference of the eccentric member 26 in a parallel orientation to the rotation axis X. Furthermore, a plurality of first lubricating oil grooves 26a (see Figure 1) are formed on the inside (support wall 21 side) of the eccentric member 26 in a radial orientation, and a plurality of second lubricating oil grooves 26b are formed on the outside (side farther from the intake camshaft 2) in a radial orientation. Note that only one of the first lubricating oil grooves 26a and the second lubricating oil grooves 26b may be formed on the eccentric member 26. The number of these first lubricating oil grooves 26a and second lubricating oil grooves 26b may be set arbitrarily.

As shown in FIG. 5, the inner periphery of the open end on the outer side (the side farther from the intake camshaft 2) of the eccentric member 26 has tapered portions 26c (inclined portions) on both sides of the engagement groove 26T, the diameter of which decreases toward the inner side (the side closer to the intake camshaft 2). When the pair of engagement pins 8 of the phase control motor M are engaged with the engagement groove 26T of the eccentric member 26, the engagement pins 8 are guided into the engagement groove 26T by the tapered portions 26c, making it easier to engage the phase control motor M with the eccentric member 26.

As shown in Figures 1 and 2, a first bearing 28 is fitted onto the circumferential support surface 26S, and this first bearing 28 is fitted into the support surface 22S of the cylindrical wall portion 22, so that the eccentric member 26 is supported so as to be rotatable about the rotation axis X relative to the intermediate member 20. Also, as shown in Figures 1 and 3, the input gear 30 is supported so as to be rotatable about the eccentric axis Y relative to the eccentric support surface 26E of the eccentric member 26 via a second bearing 29.

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

The biasing mechanism S applies a biasing force to the input gear 30 via the second bearing 29 so that a portion of the external teeth 30A of the input gear 30 meshes with a portion of the internal teeth 25A of the output gear 25. The inner race 29a of the second bearing 29 is fitted onto the eccentric support surface 26E of the eccentric member 26, and the outer race 29b of the second bearing 29 is fitted onto the inner circumference of the input gear 30, so that the biasing force of the biasing mechanism S is applied radially to the input gear 30.

This allows a portion of the external teeth 30A of the input gear 30 to mesh stably with the internal teeth 25A of the output gear 25, preventing the backlash from expanding and preventing abnormal noise.

The biasing mechanism S is constructed by combining two spring members 71 of the same shape and size, as shown in FIG. 7.

As shown in Figures 7 and 8, the spring member 71 is provided with a curved portion 72 formed by bending a spring plate material, a support portion 73 in which one side of the spring plate material of the curved portion 72 extends and contacts the bottom surface 70a of the concave portion 70, and a biasing portion 74 in which the other side of the spring plate material of the curved portion 72 extends and applies a biasing force to the inner periphery of the input gear 30, and a bent portion 75 in which the tip side of the support portion 73 is bent into a position away from the bottom surface 70a of the concave portion 70.

In other words, the curved portion 72 is formed into a shape in which the support portion 73 and the biasing portion 74 are arranged in a substantially parallel position by bending the spring plate material so that the curved portion 72 is U-shaped when viewed in the direction along the eccentric axis Y while being fitted into the concave portion 70.

In addition, in a plan view (diametric view perpendicular to the support portion 73 and the biasing portion 74), the width (axial dimension) of the support portion 73 is set to half (1/2) the width (axial dimension) of the curved portion 72, and is positioned at a position biased to one side in the width direction, and the width (axial dimension) of the support portion 73 is set to half (1/2) the width of the curved portion 72, and is positioned at a position biased to the other side in the width direction.

As a result, as shown in FIG. 7, a support side notch 73a is formed at the boundary between the curved portion 72 and the support portion 73, and a biasing side notch 74a is formed at the boundary between the curved portion 72 and the biasing portion 74, and the biasing side notch 74a is formed at the boundary between the curved portion 72 and the biasing portion 74, and the biasing side notch 74a is formed at the boundary between the curved portion 72 and the biasing portion 74, and the biasing side notch 73a is formed at the boundary between the curved portion 72 and the biasing portion 74, and the biasing side notch 74 ...

The two spring members 71 are configured as a biasing mechanism S in which they are arranged in opposite orientations so that their respective curved portions 72 are located at the circumferential ends of the concave portion 70 when viewed from the direction shown in Figures 6 and 8, and are fitted into one concave portion 70. By fitting in this manner, the two spring members 71 have their respective curved portions 72 spaced apart, and the two biasing portions 74 are arranged in parallel along the axial direction. This forms a compact biasing mechanism S.

7 and 8, the spring member 71 is curved in the region extending from the curved portion 72 to the support portion 73 so as to follow the bottom surface 70a of the concave portion 70, and forms a base end abutment position Q at a position of the curved portion 72 facing the bottom surface 70a, and forms a tip end abutment position R at the boundary between the support portion 73 and the bent portion 75. Furthermore, the biasing portion 74 has a biasing apex 74b that protrudes outward in the radial direction of the eccentric member 26 so as to apply a concentrated biasing force to the inner surface of the inner race 29a of the second bearing 29 in the direction in which the external teeth 30A of the input gear 30 meshes most deeply with the internal teeth 25A of the output gear 25.

The curved portion 72 is the main portion that generates the biasing force of the spring member 71 by elastically deforming. By combining two spring members 71 and fitting them into the recessed portion 70, as shown in Figures 6 and 7, when viewed in the direction along the eccentric axis Y, the biasing apexes 74b of the biasing portions 74 of the two spring members 71 are positioned so as to overlap. In this way, even though the structure is such that two spring members 71 are fitted into one recessed portion 70, it is also possible to maintain the balance of the biasing forces acting on the input gear 30.

This allows the biasing force to be applied from the biasing apex 74b of the two biasing parts 74 to the inner race 29a of the second bearing 29 with the base end abutment position Q at the boundary between the support part 73 and the curved part 72 of the two spring members 71 abutting against the bottom surface 70a of the concave part 70 as a fulcrum. In addition, when the biasing force is applied in this manner, the tip end abutment position R, which is the boundary between the curved part 75 and the support part 73, is maintained in a state of abutting against the bottom surface 70a of the concave part 70.

Here, for example, assuming a process in which the second bearing 29 is fitted onto the eccentric support surface 26E of the eccentric member 26 and two spring members 71 are inserted between the inner circumference of the inner race 29a of this second bearing 29 and the recessed portion 70, the spring members 71 can be inserted by abutting an insertion tool or the like against the bent portion 75 and the curved portion 72.

That is, for example, in the process of inserting the spring member 71 by applying pressure only to one point of the curved portion 72 (for example, near the base end abutment position Q), the pressure acts only on the end of the spring member 71, so the posture of the spring member 71 may deviate from the correct posture, and a part of the spring member 71 may come into strong contact with the end face 70b of the recessed portion 70, making insertion difficult. In contrast, by using a tool or the like to apply pressure to the spring member 71 at two points (for example, near the base end abutment position Q and near the tip end abutment position R) that are spaced apart in the circumferential direction of the recessed portion 70, the pressure acting on the spring member 71 is not biased, and it becomes possible to insert the spring member 71 along the axial direction while maintaining the correct posture relative to the recessed portion 70.

In addition, the spring member 71 may move in the circumferential direction of the eccentric member 26 while fitted into the recessed portion 70. The bent portion 75 is in a position where the tip side is separated from the bottom surface 70a of the recessed portion 70, and the corner (edge) of the tip of the bent portion 75 is separated from the bottom surface 70a. Therefore, even if the spring member 71 moves inside the recessed portion 70, the inconvenience of the bottom surface 70a of the recessed portion 70 being worn can be suppressed.

[Fixed ring/spring parts]
1 and 5, the fixing ring 31 is fitted into annular groove 26d formed in an outer periphery of eccentric support surface 26E of eccentric member 26, and is disposed at a position overlapping with recessed portion 70 as viewed in the radial direction. The valve timing control device 100 includes a spacer 32 at a position contacting the fixing ring 31, thereby preventing the second bearing 29 from coming off.

As shown in Figures 4 and 5, the fixing ring 31 is a C-shaped annular member that fits into the annular groove 26d of the eccentric member 26 and is supported by the eccentric member 26. The fixing ring 31 also has a restricting portion 31R that fits into the recessed portion 70 on the inner diameter side of the fixing ring 31, and a gap-containing joint 31g is disposed on the opposite side of the restricting portion 31R when viewed in the axial direction. The tip of this restricting portion 31R is arc-shaped, and is gently connected (through an arc) to the fixing ring 31 on both sides in the circumferential direction.

For example, a fixing ring 31 without the restricting portion 31R has a small radial width around the entire circumference of the fixing ring 31, making it difficult to visually confirm whether or not it is attached. In contrast, a fixing ring 31 with the restricting portion 31R has a large radial width (amount of radial protrusion) of the restricting portion 31R, making it easy to visually confirm whether or not it is attached.

In addition, in the valve timing control device 100, the restricting portion 31R is fitted into the recessed portion 70, so the fixing ring 31 does not rotate along the annular groove 26d, and the gap at the joint 31g does not cause the spring member 71 to lose its position when the joint 31g reaches the recessed portion 70. Furthermore, by using the fixing ring 31 equipped with the restricting portion 31R, the spring member 71 does not fall off the recessed portion 70 even under normal use conditions.

As shown in FIG. 8, if the thickness of the spring member 71 is the plate thickness T, and the height of the bending of the bent portion 75 of the spring member 71 based on the tip abutment position R is the bending amount H, the relationship is set so that the bending amount H is greater than the plate thickness T (H>T). Note that, as shown in FIG. 8, the bending amount H is the distance between the tip abutment position R and the highest position of the bent portion 75 in the direction along the imaginary line that connects the eccentric axis Y and the tip abutment position R with a straight line along the radial direction when viewed in the direction along the eccentric axis Y.

In this way, by making the amount of bending H greater than the plate thickness T, for example, when the spring member 71 moves in a direction (axial direction) in which it contacts the fixing ring 31, the bent portion 75 also contacts the area along the protruding direction of the restricting portion 31R.

The restricting portion 31R can contact the side surfaces of the curved portion 72, the support portion 73, and the biasing portion 74 of the spring member 71 over a wide surface. Therefore, the side surfaces of the curved portion 72, the support portion 73, and the biasing portion 74 of the spring member 71 contact the restricting portion 31R, and the bent portion 75 contacts, thereby preventing the spring member 71 from changing to an inappropriate posture and enabling the direction of action of the biasing force of the biasing mechanism S to be stabilized.

As shown in FIG. 9, the distance between the protruding end of the restricting portion 31R of the fixing ring 31 and the bottom surface 70a of the recessed portion 70 is defined as a gap G. The dimensional relationship of this gap G is set so that it is smaller than the plate thickness T of the spring member 71 (G<T).

In the figure, the inner peripheral edge of the protruding end of the regulating portion 31R is arc-shaped centered on the eccentric axis Y, and the bottom surface 70a of the recessed portion 70 is a shape that is not centered on the eccentric axis Y by smoothly protruding part of the arc shape outward, so a gap G is shown at the narrowest point between them, but the distance between the inner peripheral edge of the regulating portion 31R and the bottom surface 70a of the recessed portion 70 may be uniform, and the entire inner peripheral edge of the regulating portion 31R may have an equal gap G. The shape of the bottom surface 70a may be non-circular, such as an ellipse, but it may also be formed in an arc shape centered at a position away from the eccentric axis Y.

By making the gap G smaller than the plate thickness T in this way, even if the spring member 71 breaks, the broken object cannot pass through the gap G. For example, the broken object may fall off in the direction toward the front plate 12 and come into contact with the internal teeth 25A of the output gear 25 or the external teeth 30A of the input gear 30. This prevents the valve timing control device 100 from becoming inoperable.

As shown in FIG. 10, when viewed in the direction along the eccentric axis Y, the length (arc length) along the circumferential direction of the eccentric support surface 26E of the eccentric member 26 from the end face 70b of the recessed portion 70 to the circumferentially farthest edge of the two edges of the regulating portion 31R is defined as the regulating region length D. Hereinafter, the length (arc length) along the circumferential direction of the recessed portion 70 will be referred to as the "circumferential length."

As shown in FIG. 10, when two spring members 71 are combined and fitted into the recessed portion 70, for example, the two spring members 71 are moved integrally to one side of the recessed portion 70 (the right side in the figure) to bring the outer surface of the curved portion 72 of one spring member 71 into contact with the end face 70b, and the restricting portion 31R of the fixing ring 31 fitted into the annular groove 26d is moved to the other side (the left side in the figure) to bring the restricting portion 31R closest to the end face 70b.

In other words, in a situation where the two spring members 71 and the restricting portion 31R have moved to their limit of movement in opposite directions in the concave portion 70, the circumferential length of the gap between the curved portion 72 of the other spring member 71 and the other end face 70b is the separation distance U. Also, in this situation, the circumferential length from the curved portion 72 of the other spring member 71 to the tip of the bent portion 75 is the spring region length F. Furthermore, the dimensional relationship is set so that the restriction region length D in the circumferential direction is greater than the sum of the separation distance U and the spring region length F (D>U+F).

This dimensional relationship always holds when the restriction area length D, which is the circumferential length from the other end face 70b to the edge of the restricting portion 31R of the fixing ring 31 that is farther from the other end face 70b, is set larger than the spring area length F, which is the circumferential length from the curved portion 72 of the other spring member 71 (left side in Figure 10) in the circumferential direction of the concave portion 70 to the tip of the bent portion 75 of the other spring member 71 (D > F).

The spring region length F from the curved portion 72 of the spring member 71 to the tip of the bent portion 75 is the circumferential length along the circumferential direction of the concave portion 70 that connects the outer end position 72t of the curved portion 72 and the tip of the bent portion 75 in the extension direction. The separation distance U is the circumferential length of the concave portion 70 that connects the outer end position 72t of the curved portion 72 of the spring member 71 and the position where the arc that passes through this outer end position 72t and is centered on the eccentric axis Y intersects with the end face 70b.

As a result, by setting the relationship between the separation distance U between the curved portion 72 and the end face 70b of the concave portion 70, the spring area length F from the curved portion 72 to the tip of the bent portion 75, and the restriction area length D of the restriction portion 31R as described above, the sides of the curved portion 72, the support portion 73, and the biasing portion 74 are reliably brought into contact with the restriction portion 31R regardless of the position of the spring member 71 inside the concave portion 70, not only stabilizing the posture of the spring member 71 but also preventing any broken objects from falling out of the concave portion 70 toward the front plate 12 even if the spring member 71 breaks.

[Phase adjustment mechanism: Oldham coupling]
1, 4 and 5, the Oldham coupling Cx is composed of a plate-shaped coupling member 40 which is integrally formed with a central annular portion 41, a pair of external engagement arms 42 which protrude radially outward from the annular portion 41 along a first direction (left-right direction in FIG. 4), and an internal engagement arm 43 which protrudes radially outward from the annular portion 41 along a direction perpendicular to the first direction (up-down direction in FIG. 4). Each of the pair of internal engagement arms 43 is formed with an engagement recess 43a which is continuous with an opening of the annular portion 41.

A pair of guide grooves 11a are formed in the outer case 11 at the opening edge where the front plate 12 abuts, extending from the inner space of the outer case 11 to the outer space, in the radial direction around the rotation axis X. The groove width of the guide grooves 11a is set slightly wider than the width of the external engagement arm 42, and a pair of discharge flow paths 11b are cut out and formed in each guide groove 11a. The discharge flow paths 11b may be formed to allow lubricating oil to flow radially relative to the front plate 12.

At the opening edge of the outer case 11, one or more pockets 11c are cut out on the inner periphery along the circumferential direction in a portion other than the guide groove 11a. Foreign matter that moves to the outer periphery due to the centrifugal force caused by the rotation of the drive-side rotor A is collected in the pockets 11c.
FIG. 5 shows a case where four pockets 11c are formed.

A pair of engagement protrusions 30T are integrally formed on the end surface of the input gear 30 that faces the front plate 12. The engagement width of these engagement protrusions 30T is set slightly narrower than the engagement width of the engagement recess 43a of the internal engagement arm 43.

With this configuration, the Oldham coupling Cx can be made to function by engaging a pair of external engagement arms 42 of the coupling member 40 with a pair of guide groove portions 11a of the outer case 11, and engaging a pair of engagement projections 30T of the input gear 30 with the engagement recesses 43a of a pair of internal engagement arms 43 of the coupling member 40.

The coupling member 40 can be displaced in a first direction (left-right direction in FIG. 4) in which the external engagement arm 42 extends relative to the outer case 11, and the input gear 30 can be displaced in a second direction (up-down direction in FIG. 4) along the direction in which the engagement recess 43a of the internal engagement arm 43 is formed relative to the coupling member 40.

[Lubrication of Phase Adjustment Mechanism]
1, the intake camshaft 2 is formed with a lubricating oil passage 15 to which lubricating oil is supplied from an external oil pump P via an oil passage forming member 9. The support wall portion 21 of the intermediate member 20 has an opening 21a formed in a part of the surface that contacts the intake camshaft 2, for guiding oil into the inside of the eccentric member 26.

As described above, the eccentric member 26 is formed with a plurality of first lubricating oil grooves 26a and a plurality of second lubricating oil grooves 26b (see Figs. 1 and 5). In addition, the surface of the front plate 12 facing the coupling member 40 is formed with a lubrication recess 12a that forms a small radial gap between the surface of the coupling member 40. Note that, although this lubrication recess 12a is formed on the inner periphery of the front plate 12, it may be formed in an area that reaches the outer periphery of the front plate 12, or the lubrication recess 12a may be omitted and lubricating oil may be supplied to the gap between the front plate 12 and the coupling member 40.

As described above, a pair of discharge flow paths 11b are formed in the guide groove portion 11a (see Figures 4 and 5). Furthermore, by making the opening diameter of the opening 12b of the front plate 12 sufficiently larger than the inner diameter of the eccentric member 26, a difference in opening diameter is set between the opening edge of the front plate 12 and the inner circumference of the eccentric member 26.

With this 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 internal space of the eccentric member 26 through the opening 21a of the support wall portion 21 of the intermediate member 20. The lubricating oil supplied in this manner is supplied by centrifugal force from the first lubricating oil groove 26a of the eccentric member 26 to the first bearing 28, allowing the first bearing 28 to operate smoothly.

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

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 by the lubrication recess 12a, and is also supplied to the gap between the external engagement arm 42 of the coupling member 40 and the guide groove portion 11a of the outer case 11. This allows the coupling member 40 to operate smoothly. The lubricating oil supplied to the coupling member 40 is then discharged to the outside from the gap between the external engagement arm 42 of the coupling member 40 and the guide groove portion 11a of the outer case 11.

In particular, as shown in FIG. 1, by making the inner diameter of the eccentric member 26 smaller than the inner diameter of the opening edge of the front plate 12, a step is formed between them, so that when the engine E stops, the lubricating oil in the internal space of the eccentric member 26 can be discharged from the opening 12b of the front plate 12, reducing the amount of lubricating oil remaining inside. If a large amount of lubricating oil remains inside the valve timing control device 100, the operation of the phase adjustment mechanism C will be suppressed due to the viscosity of the lubricating oil after starting the engine E in a cold environment, but this inconvenience can be eliminated by discharging the lubricating oil when the engine E is stopped.

Furthermore, because the exhaust passage 11b is formed in the guide groove portion 11a, when starting the engine E that has been stopped in a cold environment, the lubricating oil inside can be quickly discharged through the exhaust passage 11b by centrifugal force, so that the highly viscous lubricating oil can be discharged in a short time, eliminating the effects of the viscosity of the lubricating oil and enabling the phase adjustment mechanism C to operate quickly.

As shown in FIG. 5, the front plate 12 has a convex portion 12c that protrudes inward on its inner surface (the side closer to the intake camshaft 2). The convex portion 12c is in light contact with the intermediate member 20 to the extent that it can slide against the intermediate member 20. The intermediate member 20 is restricted from moving toward the front plate 12 by abutting against the convex portion 12c. This allows the Oldham coupling Cx (coupling member 40) to operate smoothly with a predetermined gap maintained between the front plate 12 and the intermediate member 20.

[Operational form 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 control device is provided with sensors for detecting the rotation speeds (number of rotations per unit time) of the crankshaft 1 and the intake camshaft 2 of the engine E and their respective rotation phases, and the detection signals of these sensors are input to the control device.

When engine E is running, the control device maintains the relative rotational phase by driving phase control motor M at a speed equal to the rotational speed of intake camshaft 2. In response to this, advance operation is performed by reducing the rotational speed of phase control motor M below the rotational speed of intake camshaft 2, and conversely, retard operation is performed by increasing the rotational speed. As described above, advance operation increases the intake compression ratio, and retard operation decreases the intake compression ratio.

When the phase control motor M rotates at the same speed as the outer case 11 (the same speed as the intake camshaft 2), the meshing position of the external teeth 30A of the input gear 30 with the internal teeth 25A of the output gear 25 does not change, so the relative rotation phase of the driven rotor B with respect to the drive rotor A is maintained.

By driving and rotating the output shaft Ma of the phase control motor M at a speed faster or slower than the rotational speed of the outer case 11, the eccentric shaft Y in the phase adjustment mechanism C revolves around the rotation shaft X. This revolution displaces the meshing position of the external teeth 30A of the input gear 30 with the internal teeth 25A of the output gear 25 along the inner circumference of the output gear 25, and a rotational force acts between the input gear 30 and the output gear 25. In other words, a rotational force about the rotation shaft X acts on the output gear 25, and a rotational force that tries to rotate the input gear 30 about the eccentric shaft Y acts on the input gear 30.

As described above, the input gear 30 does not rotate relative to the outer case 11 because its engagement projection 30T engages with the engagement recess 43a of the internal engagement arm 43 of the coupling member 40, and a rotational force acts on the output gear 25. This rotational force causes the intermediate member 20 together with the output gear 25 to rotate about the rotation axis X relative to the outer case 11. As a result, the relative rotational phase between the driving side rotor A and the driven side rotor B is set, and the opening and closing timing is set by the intake camshaft 2.

In addition, when the eccentric axis Y of the input gear 30 revolves around the rotation axis X, the input gear 30 is displaced, and the coupling member 40 of the Oldham coupling Cx is displaced in the direction in which the external engagement arm 42 extends relative to the outer case 11 (first direction), and the input gear 30 is displaced in the direction in which the internal engagement arm 43 extends (second direction).

As mentioned above, the number of teeth on the external teeth 30A of the input gear 30 is set to one less than the number of teeth on the internal teeth 25A of the output gear 25. Therefore, when the eccentric axis Y of the input gear 30 revolves once around the rotation axis X, the output gear 25 rotates by one tooth, achieving a large reduction in speed.

[Actions and Effects of the Embodiments]
In the valve timing control device 100, the eccentric member 26 is supported on the support surface 22S on the inner circumference of the intermediate member 20 by a first bearing 28, and the input gear 30 is supported on the eccentric support surface 26E of the eccentric member 26 via a second bearing 29. In addition, a biasing mechanism S consisting of a combination of two spring members 71 is fitted into a recessed portion 70 formed in the eccentric support surface 26E of the eccentric member 26, and a biasing force is applied from the two spring members 71 to the inner circumference of the inner race 29a of the second bearing 29.

This makes it possible to maintain the state in which the biasing force of the biasing mechanism S keeps a portion of the external teeth portion 30A of the input gear 30 meshed with a portion of the internal teeth portion 25A of the output gear 25.

The eccentric member 26 supports a fixed ring 31 in the annular groove 26d of the eccentric support surface 26E, and the restricting portion 31R formed on the fixed ring 31 is fitted into the recessed portion 70. The spring member 71 is formed integrally with a curved portion 72, a support portion 73, and a biasing portion 74 by bending a spring plate material, and the end of the support portion 73 is bent in such a manner that the bent portion 75 is separated from the bottom surface 70a of the recessed portion 70.

This allows the spring member 71 to be easily inserted by applying pressure to the bent portion 75 and the curved portion 72 with an insertion tool. Because the tip side of the bent portion 75 is positioned away from the bottom surface 70a of the recessed portion 70, the inconvenience of the bottom surface 70a of the recessed portion 70 being worn down due to contact with the end of the spring member 71 can be suppressed.

In addition, since the fixing ring 31 is formed with a restricting portion 31R, it is easy to visually check whether the fixing ring 31 is attached or not. Since the restricting portion 31R is fitted into the recessed portion 70, the fixing ring 31 cannot rotate, and the inconvenience of the posture of the spring member 71 being disturbed by the gap of the joint 31g can be prevented. Since the restricting portion 31R of the fixing ring 31 contacts the side surfaces of the curved portion 72, the support portion 73, and the biasing portion 74 of the spring member 71 with a wide surface, the posture of the spring member 71 is properly maintained. In particular, since the bending amount H of the bent portion 75 formed in the spring member 71 is greater than the plate thickness T of the spring member 71, the spring member 71 can maintain its posture more properly by the contact of the restricting portion 31R.

As shown in FIG. 9, the distance between the protruding end of the restricting portion 31R of the fixing ring 31 and the bottom surface 70a of the recessed portion 70 is a gap G. Since this gap G is smaller than the plate thickness T, even if the spring member 71 breaks, the broken object cannot pass through the gap G.

As shown in FIG. 10, when the two spring members 71 and the restricting portion 31R in the concave portion 70 have moved to their limit of movement in opposite directions, the distance between the curved portion 72 of the other spring member 71 and the other end face 70b in the circumferential direction of the concave portion 70 is the separation distance U, and the spring region length from the curved portion 72 of the other spring member 71 to the tip of the bent portion 75 is F. Furthermore, the dimensional relationship is set so that the restricting region length D in the circumferential direction of the fixing ring 31 is greater than the sum of the separation distance U and the spring region length F (D>U+F).

As a result, regardless of the position of the spring member 71 inside the recessed portion 70, the sides of the curved portion 72, the support portion 73, and the biasing portion 74 are reliably brought into contact with the restricting portion 31R, not only stabilizing the position of the spring member 71 but also preventing the restriction portion 31R from causing broken objects to fall off, eliminating the inconvenience of the valve timing control device 100 becoming inoperable. In particular, even when the restriction region length D is set to be greater than the spring region length F (D>F), the restriction portion 31R similarly prevents the spring member 71 from falling off, making it possible to suppress the falling off of the determined object.

[Another embodiment]
The present invention may be configured as follows other than the above-described embodiment (common numbers and symbols as in the embodiment are used to designate components having the same functions as in the embodiment).

(a) It is possible to use a single spring member 71 as the biasing mechanism S. It is also possible to use three or more spring members 71 arranged in parallel.

Even in the configuration of this alternative embodiment (a), the dimensional relationship in which the gap G between the bottom surface 70a of the recessed portion 70 and the protruding end of the restricting portion 31R of the fixing ring 31 is made smaller than the plate thickness T of the spring member 71 remains effective.

(b) When the biasing mechanism S is configured using two spring members 71 in the same configuration as in the embodiment, it is also possible to configure the two spring members 71 so that the outer surfaces of the curved portions 72 of each of the two spring members 71 are fitted into the recessed portion 70 in a state where they are in contact with the end surface 70b of the recessed portion 70.

Even in the configuration of this alternative embodiment (b), the dimensional relationship in which the gap G between the bottom surface 70a of the recessed portion 70 and the protruding end of the restricting portion 31R of the fixing ring 31 is made smaller than the plate thickness T of the spring member 71 is effective. It is also effective to form a bent portion 75 in the spring member 71.

(c) By making the length D of the restricting region of the restricting portion 31R of the fixing ring 31 approximately equal to the width of the recessed portion 70, the restricting portion 31R closes the portion of the recessed portion 70 that opens toward the front plate 12, and in the event that the spring member 71 breaks, it becomes possible to effectively prevent the broken object from falling off.

The present invention can be used in valve timing control devices.

1. Crankshaft 2. Intake camshaft (camshaft)
Reference Signs List 25 Output gear 26 Eccentric member 26E Eccentric support surface 26d Annular groove 30 Input gear 31 Fixing ring 31R Restricting portion 40 Joint member 70 Concave portion 70a End surface 70b Bottom surface 71 Spring member 72 Curved portion 73 Support portion 74 Pressing portion 75 Restricting portion 100 Valve opening/closing timing control device A Drive side rotor B Driven side rotor C Phase adjustment mechanism E Internal combustion engine
Gap M Phase control motor (electric actuator)
T Plate thickness U Separation distance X Rotation axis Y Eccentric axis

Claims (5)

a drive-side rotor that rotates synchronously with a crankshaft of an internal combustion engine about a rotation axis;
a driven-side rotor that is disposed inside the driving-side rotor and is coaxial with the rotation axis and rotates integrally with a camshaft for opening and closing a valve of the internal combustion engine;
a phase adjustment mechanism that adjusts the relative rotation phase between the driving side rotor and the driven side rotor,
the phase adjustment mechanism comprises: an internally toothed output gear that is coaxial with the rotation axis and rotates integrally with the driven-side rotor; an externally toothed input gear that has a smaller number of teeth than the output gear, is disposed inside the output gear, and rotates about an eccentric axis parallel to the rotation axis; a coupling member that links the input gear to rotation of the drive-side rotor; an eccentric member that meshes the external teeth of the input gear with the internal teeth of the output gear; and an electric actuator that drives and rotates the eccentric member about the rotation axis,
the eccentric member has a concave portion that is recessed in a radial direction with respect to an eccentric support surface centered on the eccentric shaft and opens toward an end of the eccentric member in a direction along the eccentric shaft,
a spring member that applies a biasing force to mesh the external teeth portion of the input gear with the internal teeth portion of the output gear is fitted into the recessed portion,
a fixing ring is provided on an outer periphery of the eccentric support surface so as to overlap the concave portion when viewed in a radial direction;
The fixing ring has a restricting portion that fits into the recessed portion to prevent the spring member from falling off. the eccentric member has an annular groove on an outer periphery of the eccentric support surface of the eccentric member,
2. The valve timing control device according to claim 1, wherein the fixing ring is fitted in the annular groove. the spring member has a curved portion formed by curving a spring plate, a support portion extending one side of the spring plate at the curved portion and bringing it into contact with a bottom surface of the concave portion, a biasing portion extending the other side of the spring plate at the curved portion and applying a biasing force to an inner peripheral side of the input gear, and a bent portion bent into a position where a tip side of the support portion is separated from the bottom surface of the concave portion,
3. The valve timing control device according to claim 1, wherein the bent portion and the restricting portion overlap each other when viewed in a direction along the eccentric shaft core. The valve timing control device according to claim 3, wherein the gap between the protruding end of the restricting portion of the fixing ring and the bottom surface of the recessed portion is smaller than the thickness of the spring plate material when viewed in a direction along the eccentric axis. the spring member has a curved portion formed by curving a spring plate, a support portion extending one side of the spring plate at the curved portion and bringing it into contact with a bottom surface of the concave portion, a biasing portion extending the other side of the spring plate at the curved portion and applying a biasing force to an inner peripheral side of the input gear, and a bent portion bent into a position where a tip side of the support portion is separated from the bottom surface of the concave portion,
the two spring members are fitted into the recessed portion such that the curved portions face end faces of both ends of the recessed portion in a circumferential direction,
When viewed in a direction along the eccentric axis, when the curved portion of one of the spring members fitted into the concave portion is in a position where it contacts one of the end faces in the circumferential direction of the concave portion, and the restricting portion of the fixing ring is in a position closest to the other end face in the circumferential direction of the concave portion,
5. A valve timing control device according to claim 1, wherein a restriction area length along the circumferential direction from the other end face of the concave portion to an edge of the restricting portion of the fixing ring that is farther from the other end face is set larger than a spring area length along the circumferential direction from the other end face of the concave portion to the bent portion of the other spring member.