Valve opening / closing time control device

Abstract

A valve opening / closing timing control device (100) includes an eccentric member (26) that engages an external gear portion (30A) of an input gear (30) with an internal gear portion (25A) of an output gear (25). A concave portion (70) on the eccentric member (26) allows a spring member (71) to be disposed in the concave portion (70). The spring member (71) applies a biasing force to engage the external gear portion (30A) with the internal gear portion (25A). The concave portion (70) includes a spring support surface (70a) that receives a biasing force from the spring member (71).When viewed in a direction along an eccentric axis (Y), a cover surface (70af) on the spring support surface (70a) has a smaller protrusion amount at a circumferential direction center position (F) of the spring support surface (70a) compared to an eccentric arc surface (Sy) whose center is the eccentric axis (Y).

Description

Technical area

[0001] This disclosure generally relates to a valve opening / closing timing control device. Discussion of the state of the art

[0002] A valve timing device described in JP2008-38886A (reference 1) as a valve opening / closing timing control device has a configuration in which a concave receiving portion (64) is formed on an eccentric outer peripheral surface (40) of a planetary carrier (32 in reference 1), a spring member (70) is fitted in the receiving portion (64), and an elastic force of the spring member (70) is applied to a planetary gear (33).

[0003] In the configuration of Reference 1, the spring member (70) applies the elastic force along an application line (L) toward an internal tooth portion (31) to an external tooth portion (39) of the planetary gear (33), and the application line (L) is inclined to an eccentric direction line (E).

[0004] As further described in Reference 1, the concave receiving portion includes a support surface (a surface on one side of a rotational center line (O)) that contacts the spring member. A center portion of the support surface has a shape that gradually protrudes outward, and a support surface of the spring member is formed in a shape that gradually curves along the protrusion shape. The concave receiving portion includes wall-shaped portions formed at both ends of a circumferential direction of the planetary carrier to restrict movement of the spring member in the circumferential direction.

[0005] The valve opening / closing timing device rotates at a high speed. It is desirable that the load fluctuation be small even when the position of the spring element in the concave receiving portion fluctuates due to a relationship between the spring load and vibration.

[0006] On the other hand, it is also provided that the spring member can be displaced because a positional fluctuation of the spring member cannot be sufficiently regulated even in a case where the receiving portion is configured in a similar manner to the receiving portion in Reference 1 to have the wall-shaped portions formed at the end portions of the circumferential direction of the planetary carrier.

[0007] It is assumed that a displacement of the spring member changes a relationship between the protrusion portion on the support surface of the receiving portion and a position of the spring member contacting the protrusion portion, and causes a load of the spring member to fluctuate, resulting in an increase in vibration.

[0008] Thus, there is a need for a valve opening / closing timing control device that suppresses fluctuation of a spring load even when a position of a spring element fluctuates within a concave portion. Summary

[0009] A valve opening / closing timing control device according to this disclosure includes: a drive-side rotor that rotates about a rotational axis in synchronization with a crankshaft of an internal combustion engine; a driven-side rotor that is arranged coaxially with the rotational axis on an inner side of the drive-side rotor and rotates integrally with a camshaft for opening and closing a valve of the internal combustion engine; and a phase adjustment mechanism that adjusts a relative rotational phase between the drive-side rotor and the driven-side rotor, the phase adjustment mechanism including: an internally toothed output gear that rotates integrally with the driven-side rotor about the rotational axis as a common axis; an externally toothed input gear that has a smaller number of teeth than the output gear, is arranged on an inner side of the output gear and rotates about an eccentric axis.which is oriented parallel to the rotation axis; a coupling element that couples the input gear to rotation of the drive-side rotor; an eccentric element that engages an external toothed portion of the input gear with an internal toothed portion of the output gear; and an electric actuator that drives the eccentric element to rotate about the rotation axis, wherein a concave portion is formed on the eccentric element and is concave from an outer surface of the eccentric element in a radial direction inward in such a manner as to allow a spring element to be arranged in the concave portion, wherein the spring element applies a biasing force for engaging the external toothed portion of the input gear with the internal toothed portion of the output gear, the concave portion having a spring support surface that receives a biasing force of the spring element,the spring support surface has a cover surface, and the cover surface, when viewed in a direction along the eccentric axis, has a smaller amount of projection at a circumferential center position of the spring support surface compared to an eccentric arc surface whose center is the eccentric axis.

[0010] According to this feature configuration, the spring member fitted in the concave portion applies the biasing force from the spring support surface of the concave portion toward an inner circumferential direction of the input gear, thereby maintaining the external gear portion of the input gear in a state of meshing with the internal gear portion of the output gear. The concave portion has the spring support surface that receives the biasing force of the spring member. When viewed in the direction along the eccentric axis, the top surface of the spring support surface is formed as an arc-shaped surface whose radius of curvature is larger than that of the eccentric arc surface whose center is the eccentric axis, in such a way that the spring support surface has the smaller protrusion amount at the circumferential direction center position of the spring support surface.As a result, even when the spring element is displaced in the circumferential direction within the concave portion, a phenomenon of fluctuation in the preload force is suppressed. The valve opening / closing timing control device thus configured suppresses fluctuation in spring load even when a position of a spring element fluctuates within a concave portion. Brief description of the drawings

[0011] The foregoing and additional features and characteristics of this disclosure will become further apparent from the following detailed description considered with reference to the accompanying drawings, in which: Fig. 1 is a sectional view of a valve opening / closing timing control device; Fig. 2 is a cross-sectional view taken along the line II-II in Fig. 1 is taken; Fig. 3 is a cross-sectional view taken along the line III-III in Fig. 1 is taken; Fig. 3 is a cross-sectional view taken along the line IV-IV in Fig. 1 is taken; Fig. 5 is an exploded perspective view of the valve opening / closing timing control device; Fig. 6 is an enlarged view illustrating a positional relationship of a concave portion, spring members, an output gear, and an input gear; Fig. Figure 7 is a perspective view of a pair of spring elements; Fig. Fig. 8 is a cross-sectional view illustrating a shape of a spring support surface; and Fig. 9 is a perspective view of an eccentric element and illustrating a position of a rough surface. Detailed description

[0012] The following describes an embodiment of a valve opening / closing timing control device according to this disclosure with reference to the drawings. However, without being limited to the following embodiment, various modifications may be made within a range that does not deviate from the gist of this disclosure.

[0013] The following describes an embodiment of this disclosure with reference to the drawings. [Basic configuration]

[0014] As in Fig. 1, a valve opening / closing timing control device 100 according to this embodiment includes a drive-side rotor A that rotates in synchronism with a crankshaft 1 of an engine E as an internal combustion engine, a driven-side rotor B that rotates integrally with an intake camshaft 2, opens and closes intake valves 2B (an example of a valve), and a phase adjusting mechanism C that adjusts a relative rotational phase between the drive-side rotor A and the driven-side rotor B by a driving force of a phase control motor M.

[0015] The valve opening / closing timing control device 100 includes the drive-side rotor A and the driven-side rotor B, which are freely rotatable relative to each other about a rotation axis X within a setting range.

[0016] The engine E is configured as a four-stroke engine in which pistons 4 are housed in a plurality of cylinders 3 formed in a cylinder block, and these pistons 4 are coupled to the crankshaft 1 through connecting rods 5. A timing chain 6 (or a timing belt or the like) is wound around an output pinion 1S of the crankshaft 1 of the engine E and a drive pinion 11S of the drive-side rotor A.

[0017] Thereby, the entire valve opening / closing timing control device 100 rotates around the rotation axis X at the time of operation of the engine E. The phase adjustment mechanism C adjusts a relative rotation phase between the drive-side rotor A and the driven-side rotor B by a driving force of the phase control motor M, and thereby implements control of timings for opening and closing the intake valves 2B by cam portions 2A of the intake camshaft 2. [Valve opening / closing timing control device]

[0018] As in Fig. As shown in Figure 1, the drive-side rotor A includes an outer casing 11 having an outer periphery on which the drive pinion 11S is formed, and a front plate 12 fixed to the outer casing 11 by a plurality of fixing screws 13. The outer casing 11 is a cylindrical casing having a bottom at which an opening is formed.

[0019] As in Fig. 1 to Fig. 5, an intermediate member 20 as the output-side rotor B and the phase adjustment mechanism C (see Fig. 3 and the like) having a deceleration gear mechanism is accommodated in an interior of the outer casing 11. The phase adjustment mechanism C has an Oldham coupling Cx (see Fig. 4 and Fig. 5) which implements a phase change between the drive-side rotor A and the output-side rotor B.

[0020] The intermediate member 20 includes a support wall portion 21 and a cylinder wall portion 22 formed integrally with each other. The support wall portion 21 is coupled to the intake camshaft 2 while being oriented perpendicular to the rotation axis X. The cylinder wall portion 22 has a cylindrical shape whose center coincides with the rotation axis X and protrudes in a direction in which it is separated from the intake camshaft 2.

[0021] The intermediate member 20 is fitted in the outer housing 11 in such a manner as to be freely rotatable relative to the outer housing 11, while an outer surface of the cylinder wall portion 22 contacts an inner surface of the outer housing 11. The intermediate member 20 is fixed to the end portion of the intake camshaft 2 by a coupling bolt 23 inserted into a central through hole of the support wall portion 21.

[0022] As in Fig. 1 and Fig. 5, a groove 22a for retaining a lubricating oil is formed on an outer periphery of the cylinder wall portion 22 entirely around the cylinder wall portion 22.

[0023] As in Fig. 1, the phase control motor M is supported by the prime mover E via a support frame 7 in such a manner that an output shaft Ma of the phase control motor M is arranged 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 while being oriented perpendicular to the rotation axis X (see also Fig. 4). [Phase adjustment mechanism]

[0024] As in Fig. 1 and Fig. As shown in Fig. 5, the phase adjustment mechanism C includes the intermediate member 20, an output gear 25 formed on an inner peripheral surface of the cylinder 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 fixing ring 31, an annular spacer 32, and the Oldham coupling Cx. Although rolling bearings are used as the first bearing 28 and the second bearing 29, sliding bearings may also be used as the first bearing 28 and the second bearing 29.

[0025] As in Fig. 1, an inner circumference of the cylinder wall portion 22 of the intermediate member 20 has a support surface 22S and the output gear 25. The support surface 22S is formed on an inner side (at a position adjacent to the support wall portion 21) in a direction (hereinafter referred to as the axial direction) along the rotation axis X. The support surface 22S has a center that coincides with the rotation axis X. The output gear 25 is integrally formed with the support surface 22S on an outer side (on a side remote from the intake camshaft 2) of the support surface 22S. The output gear 25 has a center that coincides with the rotation axis X.

[0026] As in Fig. 1, Fig. 2 and Fig. 5, the eccentric member 26 is cylindrical. The eccentric member 26 has a circumferential support surface 26S formed on an inner side (a side closer to the intake camshaft 2) in the axial direction, and which is an outer circumferential surface whose center coincides with the rotation axis X. As shown in Fig. 1, Fig. 3 and Fig. 5, the eccentric member 26 has an eccentric support surface 26E formed on an outer side (a side remote from the intake camshaft 2) while being oriented parallel to the rotation axis X, and which is an outer peripheral surface whose center coincides with an eccentric axis Y. A direction along the eccentric axis Y is equal to the axial direction, and thus, the direction along the eccentric axis Y is hereinafter also simply referred to as the axial direction.

[0027] As in Fig. 5 and Fig. As shown in Fig. 6, a concave portion 70 is formed in the eccentric support surface 26E in such a manner as to be concave inward in a radial direction of the eccentric member 26 and open in an end direction (an outer end direction: a direction toward the front plate 12) in the axial direction. The concave portion 70 has a spring support surface 70a and has end wall surfaces 70b at both ends of the concave portion 70 in a circumferential direction.

[0028] As in Fig. 6 and Fig. 8, the spring support surface 70a is formed in a shape in which a central portion of the spring support surface 70a in the circumferential direction is offset inward in the radial direction from a circular arc surface whose center coincides with the eccentric axis Y (the details of this configuration are described below). As shown in Fig. 6, Fig. 8 and Fig. 9, a pair of the end wall surfaces 70b are flat when viewed in the direction along the eccentric axis Y and are formed symmetrically to each other in the circumferential direction.

[0029] A pair of spring members 71 constituting the biasing mechanism S as described below are fitted in the concave portion 70.

[0030] As in Fig. 1 and Fig. 5, a pair of engagement grooves 26T are formed in an inner circumference of the eccentric member 26 while being oriented parallel to the rotation axis X. A pair of engagement pins 8 of the phase control motor M (see Fig. 1) can engage with a pair of corresponding engagement grooves 26T.

[0031] As in Fig. 1, Fig. 2, Fig. 3 and Fig. 6, the first bearing 28 is fitted on the circumferential support surface 26S and the first bearing 28 is fitted in the support surface 22S of the cylinder wall portion 22. Thus, the eccentric member 26 is supported by the intermediate member 20 relative to the intermediate member 20 so as to be freely rotatable about the rotation axis X. As shown in Fig. 1 and Fig. 3, the input gear 30 is supported via the second bearing 29 by the eccentric support surface 26E relative to the eccentric support surface 26E of the eccentric member 26 to be freely rotatable about the eccentric axis Y.

[0032] In the phase adjustment mechanism C, the number of teeth of an external tooth portion 30A of the input gear 30 is one smaller than the number of teeth of the internal tooth portion 25A of the output gear 25, and a part of the external tooth portion 30A of the input gear 30 is engaged with a part of the internal tooth portion 25A of the output gear 25.

[0033] The preload mechanism S, which includes a pair of spring members 71, applies a preload force to the input gear 30 via the second bearing 29 in such a manner as to engage a part of the external gear portion 30A of the input gear 30 with a part of the internal gear portion 25A of the output gear 25. An inner race 29a of the second bearing 29 is fitted on the eccentric support surface 26E of the eccentric member 26, and an outer race 29b of the second bearing 29 is fitted in an inner periphery of the input gear 30, so that the preload force of the preload mechanism S is applied to the input gear 30 in the radial direction.

[0034] The preload mechanism S is configured by combining a pair of spring elements 71 having the same shape and size as shown in Fig. 7 is shown.

[0035] As in Fig. 6 and Fig. As shown in Fig. 7, the spring elements 71 each have a curved portion 72, a support portion 73, and a biasing portion 74, which are formed integrally with each other. The curved portion 72 is formed by a curved spring plate material. The support portion 73 extends from one side of the spring plate material of the curved portion 72 and faces the spring support surface 70a of the concave portion 70. The biasing portion 74 extends from an opposite side of the spring plate material of the curved portion 72 and applies the biasing force to an inner peripheral side of the input gear 30. The spring elements 71 each have a bent portion 75, which is a distal end side of the support portion 73 and which is bent in an orientation in which it is separated from the spring support surface 70a of the concave portion 70.

[0036] In other words, the spring plate material is bent in such a manner as to have a U-shape when viewed in the direction along the eccentric axis Y in a state where the curved portion 72 is fitted in the concave portion 70. Thereby, the curved portion 72 is formed in a shape in which the support portion 73 and the protrusion portion 74 are arranged in orientations that make the support portion 73 and the biasing portion 74 substantially parallel to each other.

[0037] Thus, as in Fig. 7, a support-side recess portion 73a oriented along a width direction is formed at a boundary portion between the curved portion 72 and the support portion 73, and a bias-side recess 74a oriented along the width direction is formed at a boundary portion between the curved portion 72 and the bias portion 74.

[0038] In the directional view, which is Fig. 6 and Fig. 7, the two spring elements 71 are configured as the biasing mechanism S, in which the two spring elements 71 are arranged in mutually opposite orientations in such a manner that the corresponding curved portions 72 are located at circumferential direction ends of the concave portion 70. Thus, the two spring elements 71 are fitted in the one concave portion 70. The two spring elements 71 are fitted in this manner, and thereby the corresponding curved portions 72 are separated from each other, and the two biasing portions 74 are arranged side by side along the axial direction.

[0039] In the spring member 71, a surface extending from the curved portion 72 to the support portion 73 is curved along the spring support surface 70a of the concave portion 70, forms a base end side contact portion Q at a position included in the curved portion 72 and facing the spring support portion 70a, and forms a distal end side contact portion R at a boundary between the support portion 73 and the bent portion 75.

[0040] Furthermore, the preload section 74, as shown in Fig. 6, a preload cover portion 74b protruding outward in the radial direction of the eccentric member 26 in such a manner as to apply a preload force to an inner surface of the inner race 29a of the second bearing 29 concentrated in a direction in which the external gear portion 30A of the input gear 30 engages the internal gear portion 25A of the output gear 25 most deeply.

[0041] The curved portion 72 is a main part that generates the biasing force of the spring element 71 by being elastically deformed. The two spring elements 71 are combined to be fitted in the concave portion 70, and thereby the biasing cover portions 74b of the corresponding biasing portions 74 of the two spring elements 71 are formed as shown in Fig. 6 and Fig. 7, are arranged at positions where the biasing cover portions 74b overlap with each other when viewed in the direction along the eccentric axis Y. Thus, even with a structure in which the two spring members 71 are fitted in the one concave portion 70, a balance of the biasing force applied to the input gear 30 can be maintained.

[0042] Thereby, the preload force can be applied to the inner race 29a of the second bearing 29 from the preload cover portions 74b of the two preload portions 74 in a state where the base-end contact portion Q at the boundary between the support portion 73 and the bend portion 72 of each of the two spring members 71 contacts the spring support surface 70a of the concave portion 70 as a pivot point. When the preload force is applied in this way, the distal-end contact portion R as the boundary between the bend portion 75 and the support portion 73 is maintained in a state of contacting the spring support surface 70a of the concave portion 70. [Fixing ring and spring element]

[0043] As in Fig. 1, Fig. 5 and Fig. As shown in Fig. 9, the fixing ring 31 is fitted into an annular groove 26d formed in a circular ring shape on the outer periphery of the eccentric support surface 26E of the eccentric member 26. The valve opening / closing timing control device 100 has the spacer 32 at a position where it contacts the fixing ring 31, thereby preventing the second bearing 29 from coming off. [Phase adjustment mechanism: Oldham coupling]

[0044] As in Fig. 1, Fig. 4 and Fig. 5, the Oldham coupling Cx is formed by a plate-shaped coupling element 40 in which a central circular ring portion 41, a pair of outer engagement arms 42, and inner engagement arms 43 are formed integrally with each other. A pair of outer engagement arms 42 project from the circular ring portion 41 in the radial direction outwardly along a first direction (the left-right direction in Fig. 4). The inner engagement arms 43 project from the circular ring portion 41 in the radial direction outwardly along one direction (the up-down direction in Fig. 4) that is perpendicular to the first direction. A pair of internal engagement arms 43 each has a concave engagement portion 43a formed to be continuous with an opening of the annular portion 41.

[0045] A pair of guide grooves 11a are formed in through-groove shapes at an opening edge portion included in the outer casing 11 and contacted by the front plate 12. The guide grooves 11a extend from an inner space of the outer casing 11 to an outer space and extend in the radial direction with respect to the center as the rotation axis X. The guide grooves 11a each have a groove width set slightly wider than a width of the external engagement arm 42, and a pair of discharge flow paths 11b are formed by cutting each of the guide grooves 11a. The discharge flow paths 11b may be formed in the front plate 12 in such a manner as to allow lubricating oil to flow in the radial direction.

[0046] The outer casing 11 has pockets 11c, each formed by cutting along the circumferential direction on an inner peripheral side, at a part included in the opening edge portion other than the guide groove portions 11a. The pockets 11c each collect foreign matter moving toward an outer peripheral side by receiving a centrifugal force generated by the rotation of the drive-side rotor A.

[0047] The input gear 30 has a pair of engagement projections 30T formed integrally with the input gear 30 on an end surface facing the front plate 12. The engagement projections 30T each have an engagement width set slightly narrower than an engagement width of the concave engagement portion 43a of the internal engagement arm 43.

[0048] Thus, a pair of external engagement arms 42 of the coupling member 40 are made to engage with a pair of the guide groove portions 11a of the outer casing 11, and a pair of engagement projections 30T of the input gear 30 are made to engage with the concave engagement portions 43a of the pair of internal engagement arms 43 of the coupling member 40, thereby enabling the Oldham clutch Cx to function.

[0049] The coupling element 40 can be moved in the first direction (the left-right direction in Fig. 4) in which the external engagement arms 42 extend, relative to the outer housing 11. The input gear 30 can be displaced in the second direction (the up-down direction in Fig. 4) along a formation direction of the concave engagement portions 43a of the internal engagement arms 43 relative to the coupling element 40. [Lubrication of the phase adjustment mechanism]

[0050] As in Fig. 1, a lubricating oil path 15 is formed in the intake camshaft 2. Lubricating oil is supplied to the lubricating oil path 15 from an external oil pump P via an oil path forming member 9. The support wall portion 21 of the intermediate member 20 has an opening 21a formed on a part of the surface contacting the intake camshaft 2, which guides the oil to an inside of the eccentric member 26.

[0051] Lubricating oil is supplied to the eccentric member 26 from the opening 21a. A concave lubricating portion 12a is formed along the radial direction on the surface included in the front plate 12 and facing the coupling member 40. The concave lubricating portion 12a serves as a gap from the surface of the coupling member 40. Lubricating oil is also supplied to the concave lubricating portion 12a. The concave lubricating portion 12a is formed on an inner peripheral side of the front plate 12. However, the concave lubricating portion 12a may be formed in a surface reaching an outer periphery of the front plate 12. Alternatively, a configuration without the concave lubricating portion 12a may be adopted in such a manner that the lubricating oil is supplied to a gap between the front plate 12 and the coupling member 40.

[0052] As described above, a pair of discharge flow paths 11b are formed in the guide groove portion 11a (see Fig. 4 and Fig. 5). Further, an opening diameter of the opening 12b of the front plate 12 is made sufficiently larger than an inner diameter of the eccentric member 26, and thereby a difference in opening diameter between an opening edge of the front plate 12 and the inner circumference of the eccentric member 26 is set.

[0053] With this configuration, the lubricating oil supplied from the oil pump P is supplied from the lubricating oil path 15 of the intake camshaft 2 via the opening 21a of the support wall portion 21 of the intermediate member 20 to the interior of the eccentric member 26. The lubricating oil thus supplied is supplied by centrifugal force from the eccentric member 26 to the first bearing 28, thus causing the first bearing 28 to operate smoothly.

[0054] At the same time, the lubricating oil is supplied into the interior of the eccentric member 26 by the centrifugal force to the coupling member 40 and is also supplied to the second bearing 29 and is supplied between the internal gear portion 25A of the output gear 25 and the external gear portion 30A of the input gear 30.

[0055] As in Fig. 1, the lubricating oil is supplied from the second bearing 29 between the front plate 12 and the coupling member 40 through the concave lubricating portion 12a and is also supplied to gaps between the external engagement arms 42 of the coupling member 40 and the guide groove portions 11a of the outer housing 11 (see also Fig. 5). The lubricating oil supplied to the coupling member 40 is discharged to an outside from the gaps between the external engagement arms 42 of the coupling member 40 and the guide groove portions 11a of the outer housing 11.

[0056] As in Fig. As shown in Fig. 5, the front plate 12 has convex portions 12c formed on a surface on an inner side (a side closer to the intake camshaft 2) and protruding toward the inner side. The convex portions 12c are made to lightly contact the intermediate member 20 to the extent that they can slide on the intermediate member 20. By contacting the convex portions 12c, the intermediate member 20 is prevented from moving toward the front plate 12. This allows the Oldham coupling Cx (coupling member 40) to be operated smoothly (continuously) in a state where a predetermined gap is maintained between the front plate 12 and the intermediate member 20. [Operating mode of the phase adjustment mechanism]

[0057] The phase-control motor M is controlled by a control device configured as an ECU, which is not shown in the drawings. The control device includes sensors that detect rotational speeds (the number of rotations per unit time) of the crankshaft 1 and the intake camshaft 2 in the engine E and the corresponding rotational phases of the crankshaft 1 and the intake camshaft 2. Detection signals from these sensors are input to the control device.

[0058] When the engine E is operated, the control device maintains the relative rotational phase by driving the phase control motor M at a speed equal to a rotational speed of the intake camshaft 2. In contrast, an advance angle operation is performed by decreasing a rotational speed of the phase control motor M to be lower than a rotational speed of the intake camshaft 2, and conversely, a retard angle operation is performed by increasing the rotational speed.

[0059] When the phase control motor M rotates at the same speed (the same speed as that of the intake camshaft 2) as that of the outer casing 11, an engagement position of the external gear portion 30A of the input gear 30 with the internal gear portion 25A of the output gear 25 does not vary, and thus a relative rotation phase of the driven-side rotor B to the driving-side rotor A is maintained.

[0060] In contrast, driving the output shaft Ma of the phase control motor M to rotate at a speed higher or lower than a rotational speed of the outer casing 11 causes the eccentric axis Y in the phase adjustment mechanism C to revolve around the rotational axis X. This revolution causes an engagement position of the external gear portion 30A of the input gear 30 with the internal gear portion 25A of the output gear 25 to be displaced along the inner circumference of the output gear 25, and a rotational force is applied between the input gear 30 and the output gear 25. In other words, the rotational force about the rotational axis X is applied to the output gear 25, and the rotational force to rotate the input gear 30 about the eccentric axis Y is applied to the input gear 30.

[0061] As described above, the engaging protrusions 30T engage with the concave engaging portions 43a of the internal engagement arms 43 of the coupling member 40, and thus the input gear 30 does not rotate relative to the outer housing 11, and the rotational force is applied to the output gear 25. This rotational force causes the intermediate member 20 to rotate together with the output gear 25 relative to the outer housing 11 about the rotational axis X. As a result, the relative rotational phase between the drive-side rotor A and the driven-side rotor B is adjusted, and the adjustment of opening and closing timings by the intake camshaft 2 is implemented.

[0062] When the eccentric axis Y of the input gear 30 rotates around the rotation axis X, along with the displacement of the input gear 30, the coupling element 40 of the Oldham clutch Cx is displaced relative to the outer casing 11 in the direction (first direction) in which the outer engagement arms 42 extend, and the input gear 30 is displaced in the direction (second direction) in which the inner engagement arms 43 extend.

[0063] As described above, the number of teeth of the external toothed portion 30A of the input gear 30 is set to be one smaller than the number of teeth of the internal toothed portion 25A of the output gear 25. Thus, when the eccentric axis Y of the input gear 30 revolves once around the rotational axis X, the output gear 25 rotates by an amount of one tooth, thereby achieving a large reduction in speed. [Concave section]

[0064] As in Fig. 6 and Fig. 8, the concave portion 70 has a shape that is concave inward in the radial direction when viewed in the direction along the eccentric axis Y from the eccentric support surface 26E (an example of an eccentric outer surface). When viewed in the direction along the eccentric axis Y, the end portions of the spring support surface 70a in the circumferential direction of the eccentric member 26 and the end wall surfaces 70b at both ends are formed in such a manner as to be smoothly connected to each other by curved surfaces 70c.

[0065] When the two spring members 71 are fitted in the concave portion 70, the corresponding base end contact portions Q respectively contact the end wall surface 70b and the spring support surface 70a, and the corresponding distal end contact portions R respectively contact the spring support surface 70a.

[0066] The spring support surface 70a of the concave portion 70 is formed as a bulge surface St whose radius of curvature is larger compared to an eccentric arc surface Sy having an eccentric side radius Ry whose center is the eccentric axis Y, in such a way that the spring support surface 70a is at a circumferential direction center position F (in Fig. 8 (shown as the center line) has a smaller protrusion amount. A surface included in the camber surface St and close to the center position F is referred to as a cover surface 70af.

[0067] The curvature surface St is formed as an arc having a central radius Rx whose center is the rotation axis X. The curvature surface St is not limited to an arc surface and can, for example, be part of a curvature line of an ellipse or part of a curvature line of a quadratic function.

[0068] In this configuration, a positional relationship between the center position F on the eccentric arc surface Sy in the circumferential direction of the concave portion 70 and the center position F on the cover surface 70af in the circumferential direction of the concave portion 70 is a positional relationship in which these center positions F are separated from each other by a gap G in the radial direction.

[0069] The eccentric member 26 has a cylindrical shape having a cylindrical interior whose center is the eccentric axis Y. The eccentric member 26 has a center thickness Tc, which is a radial direction thickness from the inner surface of the eccentric member 26 to the spring support surface 70a at the center position F. The center thickness Tc is set to be smaller than an end portion thickness Te, which is a thickness from the inner surface of the eccentric member 26 to each of both circumferential direction end portions of the spring support surface 70a.

[0070] A rough surface RF is formed on the cover surface 70af of the spring support surface 70a by forming a plurality of groove-shaped portions 70d oriented along the eccentric axis Y. A plurality of the groove-shaped portions 70d are formed by a laser beam. The thus formed rough surface RF functions in such a way as to suppress a phenomenon in which the spring element 71 moves relative to the spring support surface 70a in the circumferential direction (see also Fig. 9).

[0071] In this configuration, the two spring members 71 fitted in the concave portion 70 apply a biasing force from the spring support surface 70a of the concave portion 70 toward the inner periphery of the input gear 30, thus maintaining the external gear portion 30A of the input gear 30 in a state of meshing with the internal gear portion 25A of the output gear 25.

[0072] With such a configuration, the top surface 70af of the spring support surface 70a has a smaller protrusion amount when viewed in the direction along the eccentric axis Y compared to the eccentric arc surface Sy at the circumferential direction center position F on the spring support surface 70a. For this reason, even when the spring member 71 is displaced within the concave portion 70 in a direction away from the center position F, the amount of change in the biasing force is smaller, and thus no vibration is caused when the valve opening / closing timing control device 100 rotates at a high speed.

[0073] The spring member 71 in this embodiment has the distal end contact portion R that contacts a part of the spring support surface 70a and is close to the circumferential direction center position F. Accordingly, when the spring member 71 is displaced within the concave portion 70 in the direction away from the center position F, the distal end contact portion R moves in a state of contacting the cover surface 70af. Thus, even if such movement occurs, the biasing force applied by the spring member 71 is suppressed from fluctuating.

[0074] In this configuration, the rough surface RF is formed on the spring support surface 70a. Thus, when the spring member 71 moves in the circumferential direction of the spring support surface 70a as described above, the frictional force is applied to the distal end contact portion R, thereby enabling the movement of the spring member 71 to be suppressed. [Alternative embodiments]

[0075] This disclosure may be configured differently from the above-described embodiment as follows (the constituent elements having the same functions as those in the embodiment are denoted by the same reference numerals and symbols in the embodiment). (a) As partially described in the embodiment, the bulging surface St is not limited to an arc surface and may have a shape following a part of a curvature defining an ellipse, or a part of a curvature expressing a quadratic function, or a curvature having a shape of a plurality of functions connected to each other in such a manner as to protrude gradually. (b) The number of spring elements 71 used may be one. (c) The rough surface RF can be formed, for example, by knurling. The spring support surface 70a can be formed in the rough surface RF using a device that performs surface processing.

[0076] The configuration disclosed in each of the above-described embodiments (including the alternative embodiments to which the following applies) may be applied in combination with the configuration disclosed in another of the embodiments as long as there is no contradiction, and the embodiments disclosed in this specification are exemplary, and the embodiments of this disclosure are not limited to those and can be appropriately modified within the scope that does not deviate from the purpose of this disclosure.

[0077] In the embodiment described above, the following configurations are assumed.

[0078] (1) The valve opening / closing timing control device 100 includes: the drive-side rotor A that rotates about a rotation axis X in synchronization with the crankshaft 1 of the internal combustion engine (engine E); the driven-side rotor B that is arranged coaxially with the rotation axis X on an inner side of the drive-side rotor A and rotates integrally with the camshaft (intake camshaft 2) to open and close the valve of the internal combustion engine (engine E); and the phase adjusting mechanism C that adjusts a relative rotation phase between the drive-side rotor A and the driven-side rotor B.The phase adjustment mechanism C includes: an internally toothed output gear 25 that rotates integrally with the driven-side rotor B about the rotation axis X as a common axis; an externally toothed input gear 30 that has a smaller number of teeth than the output gear 25, is arranged on an inner side of the output gear 25, and rotates about the eccentric axis Y oriented parallel to the rotation axis X; the coupling member 40 that couples the input gear 30 to rotation of the drive-side rotor A; the eccentric member 26 that engages the external tooth portion 30A of the input gear 30 with the internal tooth portion 25A of the output gear 25; and the electric actuator (the phase control motor M) that drives the eccentric member 26 to rotate about the rotation axis X.The concave portion 70 is formed on the eccentric member 26 and is concave inwardly from the outer surface of the eccentric member 26 in the radial direction in such a manner as to allow the spring member 71 to be disposed in the concave portion 70. The spring member 71 applies the biasing force for engaging the external gear portion 30A of the input gear 30 with the internal gear portion 25A of the output gear 25. The concave portion 70 has the spring support surface 70a that receives the biasing force of the spring member 71. The spring support surface 70a has the cover surface 70af. When viewed in the direction along the eccentric axis Y, the cover surface 70af has a smaller protrusion amount at the circumferential direction center position F of the spring support surface 70a compared to the eccentric arc surface Sy whose center is the eccentric axis Y.

[0079] According to this configuration, the spring member 71 fitted in the concave portion 70 applies the biasing force from the spring support surface 70a of the concave portion 70 toward the inner circumference of the input gear 30, thereby maintaining the external gear portion 30A of the input gear 30 in a state of meshing with the internal gear portion 25A of the output gear 25. The cover surface 70af is formed on the spring support surface 70a of the concave portion 70. When viewed in the direction along the eccentric axis Y, the cover surface 70af has a smaller protrusion amount at the circumferential center position F of the spring support surface 70a compared to the eccentric arc surface Sy, the center of which is the eccentric axis Y.This can suppress a phenomenon in which the biasing force applied by the spring member 71 greatly fluctuates in the direction of engagement of the external gear portion 30A of the input gear 30 with the internal gear portion 25A of the output gear 25, even when the spring member 71 is displaced in the circumferential direction within the concave portion 70. This can suppress a vibration occurrence phenomenon even when the valve opening / closing timing control device 100 rotates at a high speed.

[0080] (2) In the valve opening / closing timing control device 100 of (1), it is preferable that the eccentric member 26 has the cylindrical shape having the cylindrical inner space whose center is the eccentric axis Y, the eccentric member 26 has the central thickness Tc, and the central thickness Tc is a radial direction thickness from the inner surface of the eccentric member 26 to the top surface 70af of the spring support surface 70a and is set to be smaller than the end portion thickness Te, which is a thickness from the inner surface of the eccentric member 26 to each of both circumferential direction end portions of the spring support surface 70a.

[0081] According to this configuration, the concave portion 70 is formed in such a manner as to be concave at the eccentric member 26, and even when a load is applied to the circumferential direction end portion of the spring support surface 70a, high strength on a circumferential direction end side of the concave portion 70 can prevent the end portion of the spring support surface 70a from being damaged.

[0082] (3) In the valve opening / closing timing control device 100 of (1) or (2), it is preferable that the two spring members 71 are arranged to be offset from each other in the circumferential direction of the concave portion 70.

[0083] According to this configuration, using the two spring members 71 enables the external gear portion 30A of the input gear 30 to be maintained in a state of meshing with the internal gear portion 25A of the output gear 25 even if one of the spring members 71 is damaged.

[0084] (4) In the valve opening / closing timing control device 100 of any one of (1) to (3), it is preferable that the top surface 70af of the concave portion 70 is formed in the rough surface RF.

[0085] According to this configuration, the rough surface RF suppresses movement of the spring member 71 even when an external force for displacing the spring member 71 within the concave portion 70 in the circumferential direction is applied to the spring member 71. [Industrial applicability]

[0086] This disclosure can be applied to a valve opening / closing timing control device. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2008-38886A

[0002]

Claims

[1] Valve opening / closing time control device (100) comprising: a drive-side rotor (A) which rotates synchronously with a crankshaft (1) of an internal combustion engine about an axis of rotation (X); an output-side rotor (B) arranged coaxially to the rotational axis (X) on an inner side of the drive-side rotor (A) and rotating integrally with a camshaft (2) for opening and closing a valve (2B) of the internal combustion engine (E); and a phase adjustment mechanism (C) that adjusts a relative rotational phase between the drive-side rotor (A) and the driven-side rotor (B), wherein the phase adjustment mechanism (C) comprises: an internally toothed output gear (25) that rotates integrally with the driven-side rotor (B) about the rotation axis (X) as a common axis; an externally toothed input gear (30) that has a smaller number of teeth than the output gear (25), is arranged on an inner side of the output gear (25) and rotates about an eccentric axis (Y) oriented parallel to the rotation axis (X); a coupling element (40) that couples the input gear (30) to rotation of the drive-side rotor (A); an eccentric element (26) that engages an external tooth portion (30A) of the input gear (30) with an internal tooth portion (25A) of the output gear (25); and an electric actuator (M) which drives the eccentric element (26) to rotate about the axis of rotation (X), a concave portion (70) is formed on the eccentric member (26) and is concave inwardly from an outer surface of the eccentric member (26) in a radial direction in such a way as to allow a spring member (71) to be arranged in the concave portion (70), and the spring member (71) applies a biasing force for engaging the external toothed portion (30A) of the input gear (30) with the internal toothed portion (25A) of the output gear (25), and the concave portion (70) has a spring support surface (70a) that receives a biasing force of the spring element (71), the spring support surface (70a) has a cover surface (70af), and the cover surface (70af) has a smaller protrusion amount compared to an eccentric arc surface (Sy) whose center is the eccentric axis (Y) when viewed in a direction along the eccentric axis (Y) at a circumferential direction center position (F) of the spring support surface (70a). [2] Valve opening / closing timing control device (100) according to claim 1, wherein the eccentric element (26) has a cylindrical shape having a cylindrical interior whose center is the eccentric axis (Y), and the eccentric member (26) has a central thickness (Tc), and the central thickness (Tc) is a radial direction thickness from an inner surface of the eccentric member (26) to the cover surface (70af) of the spring support surface (70a) and is set to be smaller than an end portion thickness (Te), which is a thickness from the inner surface of the eccentric member (26) to each of both circumferential direction end portions of the spring support surface (70a). [3] The valve opening / closing timing control device (100) according to claim 1 or 2, wherein a pair of said spring members (71) are arranged to be offset from each other in a circumferential direction of said concave portion (70). [4] The valve opening / closing timing control device (100) according to any one of claims 1 or 2, wherein the cover surface (70af) of the concave portion (70) is formed into a rough surface (RF).

Images