JP-7855232-B2 - Variable valve timing mechanism for internal combustion engines

JP7855232B2JP 7855232 B2JP7855232 B2JP 7855232B2JP-7855232-B2

Inventors

鈴木幹人
杉浦憲

Assignees

株式会社オティックス

Dates

Publication Date: 20260508
Application Date: 20221209

Claims (2)

A variable valve timing mechanism for an internal combustion engine, comprising: an input arm (3) that is pressed and oscillated by a cam (1); an output arm (4) that oscillates and presses a valve; a switching pin (5) displaceably provided on the output arm (4); and a drive device (6) that displaces the switching pin (5) to a connecting position on the oscillation trajectory of the input arm (3) so that the input arm (3) and the output arm (4) are connected and oscillate together, The variable valve timing mechanism for an internal combustion engine is characterized in that the drive unit (6) includes an electromagnetic solenoid (30) located outside the output arm (4), a movable element (31) driven by the electromagnetic solenoid (30) to move toward the pivot center of the output arm (4), and a connecting member (32) that connects the tip of the movable element (31) and the rear end of the switching pin (5) to prevent them from coming apart.
A variable valve timing mechanism for an internal combustion engine, comprising: an input arm (3) that is pressed and oscillated by a cam (1); an output arm (4) that oscillates and presses a valve; a switching pin (5) displaceably provided on the output arm (4); and a drive device (6) that displaces the switching pin (5) to a connecting position on the oscillation trajectory of the input arm (3) so that the input arm (3) and the output arm (4) are connected and oscillate together, The variable valve timing mechanism for an internal combustion engine is characterized in that the drive unit (6) includes an electromagnetic solenoid (30) located outside the output arm (4) and a movable element (31) that is driven by the electromagnetic solenoid (30) to move and press against the rear end of the switching pin (5), and the rear end of the switching pin (5) is made into an arc pad (36) having an arc surface centered on the pivot point of the output arm (4), so that the contact between the movable element (31) and the rear end of the switching pin (5) does not come off when the output arm (4) swings.

Description

This invention relates to a variable valve timing mechanism for an internal combustion engine. One type of variable valve timing mechanism for internal combustion engines, as described in Patent Documents 1 and 2, includes an input arm that is pressed and oscillated by a cam, an output arm that oscillates and presses the valve, a switching pin displaceably mounted on the output arm, a drive device that displaces the switching pin to a connected position that falls within the oscillation trajectory of the input arm, a return spring that displaces the switching pin to an unconnected position that does not fall within the oscillation trajectory of the input arm, and a lost motion spring that brakes the free oscillation of the input arm when the switching pin is in the unlocked position. A hydraulic drive system is commonly used to drive the switching pin. For example, the hydraulic drive system described in Patent Document 1 has an oil passage formed in the cylinder head, and a hydraulic lash adjuster is mounted in communication with this oil passage. The output arm is pivotably supported by the hydraulic lash adjuster, and the switching pin is displaced by oil supplied from the hydraulic lash adjuster to the hydraulic chamber within the output arm. Such hydraulic drive systems have the problem of difficulty in improving switching responsiveness. The electromechanical actuator drive device described in Patent Document 2 is configured such that the rear end of the switching pin protrudes from the output arm, the electromechanical actuator is mounted on the outside of the output arm, and the rear end of the switching pin is pressed and displaced by a cap provided at the tip of the plunger of the electromechanical actuator. This electromechanical actuator drive device is considered to easily improve switching responsiveness. The cap has a concave surface centered on the pivot axis, preventing the rear end of the switching pin from coming off the concave surface during the oscillation of the output arm. However, the rear end of the switching pin and the concave surface of the cap slide against each other during the oscillation. Furthermore, the electromagnetic solenoid moves not only the plunger but also the cap, resulting in a slower movement speed. Japanese Patent Publication No. 2016-61287European Patent Application Publication No. 2050933 Figure 1 shows the variable valve timing mechanism of Embodiment 1, where (a) is a perspective view from above and (b) is a perspective view from above after being cut vertically.Figure 2 is a perspective view of the mechanism from below.Figure 3 shows the operation of the mechanism during coupling, with (a) being a cross-sectional view at the base circle position and (b) being a cross-sectional view at the nose position.Figure 4 shows the operation of the mechanism when it is not coupled, with (a) being a cross-sectional view when it is in the base circle and (b) being a cross-sectional view when it is in the nose.Figure 5 shows the variable valve timing mechanism of Embodiment 2, where (a) is a perspective view from above and (b) is a perspective view from below.Figure 6 shows the operation of the mechanism during coupling, with (a) being a cross-sectional view at the base circle position and (b) being a cross-sectional view at the nose position.Figure 7 shows the operation of the mechanism when it is not coupled, with (a) being a cross-sectional view when it is in the base circle and (b) being a cross-sectional view when it is in the nose. 1. Input Arm The cam contact portion of the input arm may be a slipper or a roller. 2. Output Arm The pivot point of the output arm is preferably located at the rear end of the output arm for ease of mounting the input arm, but it may also be located in the center of the output arm. 3. Connecting Members The connecting members may be links or springs.