DE-102018114793-B4 - Valve opening/closing time control device

DE102018114793B4DE 102018114793 B4DE102018114793 B4DE 102018114793B4DE-102018114793-B4

Abstract

Valve opening/closing time control device (1) with: a drive-side rotating component (A) which is rotatably arranged about a rotational axis (X) and rotates synchronously with a crankshaft (2) of an internal combustion engine (E); a driven-side rotary component (B) which is rotatably arranged about the axis of rotation (X) and is integrally connected with a camshaft (3) for opening and closing a valve (3B) of the internal combustion engine (E) in a state in which the driven-side rotary component (B) is rotatable relative to the drive-side rotary component (A); a phase adjustment mechanism (C) that specifies a relative rotational phase between the drive-side rotary component (A) and the driven-side rotary component (B) by means of a drive force of an electric actuator (M), wherein the phase adjustment mechanism (C) comprises a ring gear (21), an inner gear (22) and a drive shaft (24), the ring gear (21) being arranged coaxially with the axis of rotation (X) and having an internal toothed section (21A), the inner gear (22) being arranged coaxially with an eccentric axis (Y) arranged parallel to the axis of rotation (X) and having an external toothed section (22A) which engages with a portion of the internal toothed section (21A) of the ring gear (21), the drive shaft (24) being fitted into the inner gear (22) and being coaxial with the axis of rotation (X), the phase adjustment mechanism (C) being designed as a differential reduction gear mechanism in which the inner gear (22) rotates about the axis of rotation (X) while in a state in which the drive shaft (24) is driven by a driving force of the electric actuator (M) to rotate about the axis of rotation (X) is driven to rotate around the eccentric axis (Y); a preloading component (25) provided on an outer circumference of the drive shaft (24), wherein the preloading component (25) exerts a preload force to engage the external toothed section (22A) of the inner gear (22) with the internal toothed section (21A) of the ring gear (21); and a limiting section (R) which is provided on the drive shaft (24) to limit a displacement of the inner wheel (22) in a direction in which the inner wheel (22) is separated from the ring gear (21) against the preload force of the preloading component (25), in which the drive shaft (24) has an eccentric surface (24BS) defined with respect to the eccentric axis (Y) and in which a recessed section (24D) is provided, wherein a spring (25) serving as the preload element is fitted into the recessed section (24D), the boundary section (R) is formed by at least one of opposite outer edge sections of the recess section (24D) in a circumferential direction of the eccentric surface (24BS), wherein at least one of the opposite outer edge sections projects outwards in a radial direction.

Inventors

Eiji Miyachi

Assignees

AISIN CORPORATION

Dates

Publication Date: 20260513
Application Date: 20180620
Priority Date: 20170623

Claims (3)

Valve opening/closing timing control device (1) comprising: a drive-side rotary component (A) rotatably arranged about an axis of rotation (X) and rotating synchronously with a crankshaft (2) of an internal combustion engine (E); a driven-side rotary component (B) rotatably arranged about the axis of rotation (X) and rotating integrally with a camshaft (3) for opening and closing a valve (3B) of the internal combustion engine (E) in a state in which the driven-side rotary component (B) is rotatable relative to the drive-side rotary component (A); a phase adjustment mechanism (C) which specifies a relative rotational phase between the drive-side rotary component (A) and the driven-side rotary component (B) by a drive force of an electric actuator (M), where the phase adjustment mechanism (C) comprises a ring gear (21), an inner gear (22) and a drive shaft (24), the ring gear (21) is arranged coaxially with the axis of rotation (X) and has an internal toothed section (21A), the inner gear (22) is arranged coaxially with an eccentric axis (Y) which is arranged parallel to the axis of rotation (X) and has an external toothed section (22A) which engages with a portion of the internal toothed section (21A) of the ring gear (21), the drive shaft (24) is fitted into the inner gear (22) and is coaxial with the axis of rotation (X), the phase adjustment mechanism (C) is designed as a differential reduction gear mechanism is, in which the inner gear (22) rotates about the axis of rotation (X), while in a state in which the drive shaft (24) is driven to rotate about the axis of rotation (X) by a driving force of the electric actuator (M), it rotates about the eccentric axis (Y); a preloading element (25) provided on an outer circumference of the drive shaft (24), wherein the preloading element (25) exerts a preload force to engage the external toothed section (22A) of the inner gear (22) with the internal toothed section (21A) of the ring gear (21); and a limiting section (R) provided on the drive shaft (24) to limit a displacement of the inner gear (22) in a direction in which the inner gear (22) is separated from the ring gear (21) against the preload force of the preloading element (25), wherein the drive shaft (24) has an eccentric surface (24BS) defined with respect to the eccentric axis (Y) and wherein a recessed section (24D) is provided, a spring (25) serving as the preloading element being fitted into the recessed section (24D), the limiting section (R) being formed by at least one of opposing outer edge sections of the recessed section (24D) in a circumferential direction of the eccentric surface (24BS), the at least one of the opposing outer edge sections projecting outwards in a radial direction.
Valve opening/closing time control device (1) according to Claim 1 , in which the inner wheel (22) is supported on the eccentric surface (24BS) via a bearing (27) with an inner circumferential surface (S) on which the preload force is applied by the preloading component (25), wherein the limiting section (R) is designed such that it comes into contact with the inner circumferential surface (S) of the bearing (27) to limit a displacement of the inner wheel (22).
Valve opening/closing time control device (1) according to one of the Claims 1 until 2 , in which the limiting section (R) is formed by a limiting component (45) which is mounted on the outer circumference of the drive shaft (24).

Description

TECHNICAL AREA This disclosure relates generally to a valve opening/valve closing time control device. BACKGROUND A known valve opening/closing time control device, which specifies a relative rotational phase between a drive-side rotary component and a driven-side rotary component by a drive force of an electric actuator, is, for example, in the JP 2008- 38 886 A described in the following, which is referred to as Document 1. More precisely, Document 1 discloses a differential reduction gear mechanism with a ring gear (an inner gear section) arranged coaxially with an axis of rotation, an inner gear (a planet gear or a second gear component) arranged coaxially with an eccentric axis parallel to the axis of rotation, and a drive shaft (a planet carrier) fitted internally to the inner gear such that an external toothed section of the inner gear engages with a portion of an internal toothed section of the ring gear. The valve opening/closing timing control device disclosed in document 1 further comprises a preload element (a spring element) located in an external area of the drive shaft at a position that does not coincide with or overlap a position where the external toothed section of the inner gear engages with the internal toothed section of the ring gear (i.e., does not coincide with or overlap an eccentric direction). The preload element applies a preload force to engage the external toothed section of the inner gear with the internal toothed section of the ring gear. Furthermore, in the valve opening/closing time control device disclosed in document 1, a recessed section (a receiving section) is provided on the outer circumference of the drive shaft, so that a leaf spring, which forms the spring component, is fitted into the recessed section to exert the preload force. According to the valve opening/closing timing control device disclosed in Document 1, the inner gear (the planet gear or the second gear component) is supported by at least three sections, which include a section where an inner circumferential surface of a central bore of the inner gear and a line of application of the elastic force intersect, a section where the inner circumferential surface of the central bore of the inner gear and an outer circumferential surface of the drive shaft (of the planet carrier) come into contact with each other, and a section where the inner gear and the ring gear (the internal toothing section) are in mesh with each other. With the aforementioned design, even when a cam oscillation torque is transmitted to the valve opening/closing timing control device, the clearance of the inner gear is limited, thus preventing the generation of abnormal noise. That is to say, according to the valve opening/closing timing control device disclosed in Document 1, the inner gear is supported at the three sections to stabilize its position, while the gap at a toothed section between the inner gear and the ring gear is also reduced, thus limiting the generation of abnormal noise and phase variation. At this point, in an assumed design where the inner gear is arranged to rotate about the eccentric axis, and the toothed section of the inner gear and the toothed section of the ring gear are engaged in a state where a preload force is applied in the direction in which the toothed sections of the inner and outer gears engage with each other, the aforementioned engagement state is maintained by the large preload force. Consequently, the generation of abnormal noise is limited, and phase variation is also limited. Nevertheless, the high preload force causes the tooth surfaces of the inner gear and the tooth surfaces of the ring gear to come into strong contact with each other, generating frictional resistance that can increase the rotational load. Consequently, the response speed of the valve opening/closing timing control device can be reduced. Therefore, there is a need for a valve opening/closing time control device that limits the generation of abnormal noise at a gear section without increasing the preload force of a preload component and that limits phase variation. JP 2009- 215 954 A discloses a valve timing control device in which a contour of an eccentric outer circumferential surface part is elliptically formed, with a secondary axis direction in a base diameter direction. SUMMARY A valve opening/closing time control device according to the invention has the features of claim 1. Further developments of the invention are specified in the dependent claims. Accordingly, in a design where the preloading component is used with a low preload force (small spring constant), the displacement of the outer tooth section of the inner gear relative to the inner tooth section of the ring gear is limited by the limiting section when the outer tooth section is displaced away from the inner tooth section due to the application of a cam oscillation torque. This prevents the inner gear from moving beyond the limiting section's setpoint. Abnor