JP2013194555A - Variable valve gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable valve gear configured to reduce variation in working angle.SOLUTION: A variable valve gear includes: a drive shaft 10 which rotates in synchronization with a crankshaft included in an internal combustion engine; a control sleeve 18 which is rotatably provided around the drive shaft 10 and equipped with an eccentric hole 18a and a first gear 18b on an outer peripheral surface so as to change a position of a central axis 18c of the eccentric hole 18a; a camshaft 12 which is rotatably provided around the drive shaft 10 so as to perform non-uniform rotational motion in accordance with a position of the central axis 18c of the eccentric hole 18a; a control shaft 20 which includes a second gear 20a provided on an outer peripheral surface; and a toothed gear 22 which includes a third gear 22a provided on an outer peripheral surface and engaged with the first gear 18b and a fourth gear 22b provided on an inner peripheral surface, and configured to be mounted on the control shaft 20 when the second gear 20a is engaged with the fourth gear 22b.

Description

  The present invention relates to a variable valve gear.

  2. Description of the Related Art There is known a variable valve operating apparatus that variably controls a working angle of a cam that drives an intake valve or an exhaust valve mounted on an internal combustion engine. For example, Patent Document 1 discloses a technique for making the working angle of a cam variable by decentering the center of a disk provided on the drive shaft with respect to the drive shaft.

JP 2006-336659 A

  Many components are used in the variable valve operating apparatus. Tolerances occurring in individual parts may be integrated over the entire variable valve system, resulting in large variations in dimensions. As a result, even within, for example, one variable valve operating device, the operating angle varies from cylinder to cylinder. Due to the variation in the operating angle, fuel consumption and exhaust gas are deteriorated. In view of the above problems, the variable valve gear disclosed in the present specification aims to reduce the variation in the operating angle.

  The present invention includes a drive shaft that rotates in synchronization with a crankshaft provided in an internal combustion engine, a rotation shaft that is rotatably provided around the drive shaft, an eccentric hole, and a first gear portion that is provided on an outer peripheral surface, A control sleeve that changes the position of the central axis of the eccentric hole, a camshaft that is rotatably provided around the drive shaft and that rotates at a constant speed according to the position of the central axis of the eccentric hole, and an outer peripheral surface A control shaft including a second gear portion provided on the outer peripheral surface, a third gear portion provided on the outer peripheral surface and meshing with the first gear portion, and a fourth gear portion provided on the inner peripheral surface. And a gear mounted on the control shaft as a result of meshing of the part and the fourth gear part.

  The said structure WHEREIN: The tooth pitch in the said 4th gear part can be made into the structure smaller than the tooth pitch in the said 3rd gear part.

  According to the variable valve apparatus disclosed in the present specification, it is possible to reduce the variation in the operating angle.

FIG. 1A is a side view illustrating the variable valve operating apparatus according to the first embodiment. FIG. 1B is a front view illustrating the control sleeve. FIG. 2A is a front view illustrating a control axis. FIG. 2B is a front view illustrating a gear. FIG. 2C is a front view illustrating a state where a gear is mounted on the control shaft. FIG. 2 (d) is an enlarged view of FIG. 2 (c). FIG. 3A is a diagram in which the gear is removed from the control shaft. FIG. 3B is a front view illustrating gear position adjustment. FIG. 3C is an enlarged view of FIG.

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

  The first embodiment is an example in which the operating angle is adjusted using a gear 22 provided on the control shaft 20. FIG. 1A is a side view illustrating a variable valve apparatus 100 according to the first embodiment. FIG. 1B is a front view illustrating the control sleeve 18.

  As shown in FIG. 1A, the mechanisms A and B of the variable valve operating apparatus 100 include a camshaft 12, a rocker arm 14, a valve 16, a control sleeve 18, a gear 22, a cap 24, and an E ring 26, respectively. Mechanism A and mechanism B correspond to different cylinders of the internal combustion engine (not shown). The camshaft 12 has a cylindrical shape and is rotatably provided around the drive shaft 10. The cam shaft 12 includes, for example, two cam lobes 12a. When the cam lobe 12a contacts the roller 14a of the rocker arm 14 and presses the valve 16, the valve 16 is opened. The control sleeve 18 is rotatably provided around the drive shaft 10.

  A drive shaft 10 shown in FIG. 1A rotates in synchronization with a crankshaft (not shown) of the internal combustion engine. As shown in FIG. 1B, the control sleeve 18 includes an eccentric hole 18a, and includes a first gear portion 18b on the outer peripheral surface. The rotational force of the drive shaft 10 is applied to the camshaft 12 through, for example, a drive disk (not shown) provided on the inner peripheral surface of the eccentric hole 18a of the control sleeve 18 and a pin member (not shown) connected to the camshaft 12. introduce. When the rotational force is transmitted, the camshaft 12 rotates around the drive shaft 10. As the control sleeve 18 rotates, the position of the central axis 18c of the eccentric hole 18a changes. Depending on the position of the central axis 18c, the rotational speed of the camshaft 12 during one rotation changes. The operating angle is changed by the camshaft 12 performing non-uniform rotation. As will be described later, the position of the control sleeve 18 in the rotational direction of the drive shaft 10 is determined by rotating the control shaft 20.

  As shown in FIG. 1A, the control shaft 20 is arranged in parallel with the drive shaft 10, for example. The gear 22 is provided on the outer peripheral surface of the control shaft 20. The cap 24 and the E ring 26 are provided on the outer peripheral surface of the control shaft 20 and fix the gear 22 in the axial direction.

  FIG. 2A is a front view illustrating the control shaft 20. As shown in FIG. 2A, a second gear portion 20 a is provided on the outer peripheral surface of the control shaft 20. FIG. 2B is a front view illustrating the gear 22. As shown in FIG. 2B, a third gear portion 22a is provided on the outer peripheral surface of the gear 22, and a fourth gear portion 22b is provided on the inner peripheral surface.

  FIG. 2C is a front view illustrating a state where the gear 22 is attached to the control shaft 20. FIG. 2 (d) is an enlarged view of FIG. 2 (c). The gear 22 is attached to the control shaft 20 by meshing the fourth gear portion 22b and the second gear portion 20a. As the third gear portion 22 a meshes with the first gear portion 18 b of the control sleeve 18, the position of the control sleeve 18 in the rotational direction of the drive shaft 10 is determined. By rotating the control shaft 20, the fourth gear portion 22b rotates and the position of the control sleeve 18 is adjusted.

  In FIG.2 (c) and FIG.2 (d), the tooth | gear 22c of the 4th gear part 22b has meshed | engaged with the tooth | gear 20b and the tooth | gear 20c of the 2nd gear part 20a. The tooth 22d is located on the left side of the tooth 22c of the fourth gear portion 22b. As shown in FIG. 2D, the tooth pitch in the third gear portion 22a is L1, and the tooth pitch in the fourth gear portion 22b is L2. Next, the position adjustment of the gear 22 will be described.

  FIG. 3A is a side view of an example in which the gear 22 is removed from the control shaft 20. FIG. 3B is a front view illustrating gear position adjustment. FIG. 3C is an enlarged view of FIG.

  As shown in FIG. 3A, the gear 22 is removed from the control shaft 20. As shown in FIGS. 3 (b) and 3 (c), the gear 22 is attached to the control shaft 20 after being rotated to the right in the drawing. The teeth 22d mesh with the teeth 20d and teeth 20b of the second gear portion 20a. The tooth 22c is located on the right side of the tooth 20c. That is, the gear 22 is rotated by one tooth of the fourth gear portion 22b. The rotation angle of the gear 22 is assumed to be θ. As a result, the position of the gear 22 can be adjusted using the second gear portion 20a and the fourth gear portion 22b. Since the third gear portion 22a on the outer periphery of the gear 22 is rotated by adjusting the position of the gear 22, the control sleeve 18 including the first gear portion 18b meshing with the third gear portion 22a is also rotated. As a result, the position of the control sleeve 18 can be adjusted by adjusting the position of the gear 22. That is, the position of the central axis 18c can be adjusted. As a result, the working angle of the camshaft 12 changes. After adjusting the operating angle, the variable valve apparatus 100 is assembled to the vehicle.

  In the mechanisms A and B shown in FIG. 1A, the position of the gear 22 in the rotational direction of the control shaft 20 can be varied. For example, in the mechanism A, the gear 22 is rotated by one tooth of the fourth gear portion 22b, and in the mechanism B, the gear 22 is rotated by two teeth of the fourth gear portion 22b. Thereby, the position adjustment of the central shaft 18c can be performed for each cylinder. Therefore, even when tolerance variation occurs, the working angle can be adjusted for each cylinder.

  In addition, the operating angle can be easily adjusted by removing and rotating the gear 22 and reattaching it to the control shaft 20. For example, since the work is simpler than when the entire variable valve apparatus 100 is reassembled, the cost of the variable valve apparatus 100 can be reduced.

  By making the tooth pitch L2 in the fourth gear part 22b shown in FIG. 2B smaller than the tooth pitch L1 in the third gear part 22a, the angle θ can be reduced. That is, the position of the gear 22 can be adjusted more finely. Thereby, the position of the center shaft 18c can be finely adjusted, and the rotational speed of the camshaft can be finely adjusted. However, the pitch L1 may be the same as the pitch L2. The internal combustion engine to which the variable valve operating apparatus 100 is applied may be, for example, a 2-cylinder, 4-cylinder, or 8-cylinder. The number of cam lobes included in the camshaft 12 corresponds to the number of valves 16 to be driven.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

DESCRIPTION OF SYMBOLS 10 Drive shaft 12 Camshaft 18 Control sleeve 18a Eccentric hole 18b 1st gear part 20a 2nd gear part 22a 3rd gear part 22b 4th gear part 18c Central axis 20 Control shaft 22 Gear 24 Cap 24 E ring 100 Variable valve gear L1, L2 pitch

Claims (2)

A drive shaft that rotates in synchronization with a crankshaft included in the internal combustion engine;
A control sleeve that is rotatably provided around the drive shaft, includes an eccentric hole, and a first gear portion provided on an outer peripheral surface, and changes the position of the central axis of the eccentric hole;
A camshaft that is rotatably provided around the drive shaft, and that performs a non-uniform speed rotation according to the position of the central axis of the eccentric hole;
A control shaft including a second gear portion provided on the outer peripheral surface;
A third gear portion provided on the outer peripheral surface and meshing with the first gear portion; and a fourth gear portion provided on the inner peripheral surface, wherein the second gear portion and the fourth gear portion mesh with each other to control the control. And a gear mounted on the shaft. The variable valve operating apparatus according to claim 1, wherein a tooth pitch in the fourth gear portion is smaller than a tooth pitch in the third gear portion.

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