JP2017044109A - Variable valve mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable valve mechanism which is constructed to allow an output member of a variable valve timing mechanism to be fastened to one end of a cam shaft while easily and accurately holding a clearance of the cam shaft inserted through a shaft hole of a rotation transmitting member, without hindering the relative rotation of the rotation transmitting member and the cam shaft during the operation of an internal combustion engine.SOLUTION: A cam shaft 2 is inserted through a shaft hole 10 of a sprocket 1 at a clearance 6 therefrom. A variable valve timing mechanism 3 has an output member 30 at one end of the cam shaft 2, which is fastened coaxially to the cam shaft 2 with a center bolt 5. A holding material 7 is provided for filling up the clearance 6. The holding material 7 is formed of a material to be separated from the clearance 6 with the relative rotation of the sprocket and the cam shaft 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a variable valve mechanism, and more specifically, a valve mechanism that opens and closes an intake valve and an exhaust valve by power of an output shaft (crankshaft) of an internal combustion engine, and includes at least one of the intake valve and the exhaust valve. The present invention relates to a variable valve mechanism having a variable valve timing mechanism capable of adjusting an opening / closing timing.

  As a valve mechanism of an internal combustion engine, for example, as disclosed in Patent Document 1, there is one provided with a variable valve timing mechanism.

  Here, in a general variable valve mechanism, as shown in FIG. 2, any one of a rotation transmission member 1 that is driven to rotate by receiving the power of the output shaft of the internal combustion engine, and an intake valve or an exhaust valve of the internal combustion engine. A camshaft 2 provided with a cam for opening and closing one of them, and provided between the rotation transmission member 1 and the camshaft 2, outputs the rotational driving force input from the rotation transmission member 1 to the camshaft 2. In addition, a variable valve timing mechanism 3 that adjusts the rotation phase between the rotation transmission member 1 and the camshaft 2 is provided.

  The variable valve mechanism shown in FIG. 2 employs a sprocket 1 as a rotation transmission member. A timing chain is wound around the sprocket 1 and the sprocket provided on the output shaft of the internal combustion engine, and the sprocket 1 is driven to rotate by receiving power from the output shaft of the internal combustion engine. . The camshaft 2 is provided corresponding to an intake valve and an exhaust valve of the internal combustion engine. A shaft hole 10 is formed at the center of the sprocket 1, and the camshaft 2 is inserted into the shaft hole 10. Therefore, the rotation center axes of the sprocket 1 and the camshaft 2 are arranged coaxially. The inner diameter of the shaft hole 10 of the sprocket 1 is slightly larger than the outer diameter of the camshaft 2, and a clearance 6 is formed between the inner peripheral surface of the shaft hole 10 of the sprocket 1 and the outer peripheral surface of the camshaft 2. .

  Further, the variable valve timing mechanism 3 of the variable valve mechanism adjusts the rotational phase of the sprocket 1 and the rotational phase of the camshaft 2 within a predetermined range, and an output member (fixed to one end of the camshaft 2) (Hereinafter referred to as a cam gear) 30. The variable valve timing mechanism 3 shown in FIG. 2 is connected to the sprocket 31, the planetary gear 32 provided between the cam gear 30 and the gear sprocket 31, and connected to the planetary gear 32 and driven by a motor. And an eccentric shaft 33. The cam gear 30 is accommodated in a recess 11 formed in the sprocket. A clearance 8 is formed between the outer peripheral surface of the cam gear 30 and the inner peripheral surface of the recess 11 of the sprocket 1 so as not to interfere with each other.

  A female screw hole 20 is formed at one end of the camshaft 2 so as to open at the center of one end face of the camshaft 2 and extend in the axial direction of the camshaft 2. The cam gear 30 of the variable valve timing mechanism 3 has a center hole 35 formed at the center thereof. The fastening member shown in FIG. 2 is constituted by a center bolt 5. The shaft portion of the center bolt 5 is inserted into the center hole 35 of the cam gear 30, and the male screw portion 50 is screwed into the female screw hole 20 of the cam shaft 2, thereby rotating the cam gear 30 to one end of the cam shaft 2. Fastened so that the central axis is coaxial. That is, the rotation center axes of the sprocket 1, the camshaft 2, and the output member 30 of the variable valve timing mechanism 3 are coaxially located.

JP 2010-159738 A

  In the variable valve mechanism configured as described above, when the cam gear 30 is fastened to one end of the cam shaft 2 with the center bolt 5, the rotation of the cam gear 30 is caused by the reaction force that rotates the center bolt 5 about the axis. The center axis is deviated from the rotation center axis of the camshaft 2, and as a result, the rotation center axis of the sprocket 1 is deviated from the rotation center axis of the camshaft 2, and as shown in FIG. The inner peripheral surface interferes with the outer peripheral surface of the camshaft, and friction is generated when the camshaft 2 is rotated relative to the sprocket 1 by the variable valve timing mechanism 3, which may affect the adjustment of the rotational phase. There was a problem that there was.

  The present invention has been made in view of the above-described problems. The output member of the variable valve timing mechanism is provided with the clearance between the rotation transmission member and the camshaft inserted through the shaft hole easily and accurately. A variable motion that can be fastened to one end of the camshaft by a fastening member and that does not hinder the relative rotation of the rotation transmitting member and the camshaft when the internal combustion engine is operated. An object is to provide a valve mechanism.

  In order to achieve the above object, the present invention is provided with a rotation transmission member that is rotationally driven by receiving the power of the output shaft of the internal combustion engine, and a cam for opening and closing at least one of the intake valve and the exhaust valve of the internal combustion engine. And a variable valve timing mechanism that outputs a rotational driving force input from the rotation transmission member to the camshaft and adjusts a rotation phase between the rotation transmission member and the camshaft, The rotation transmitting member is inserted into a shaft hole formed in the center thereof with the camshaft having a clearance, and the variable valve timing mechanism is connected to one end of the camshaft by a fastening member coaxially with the camshaft. A variable valve mechanism having an output member to be fastened, having a holding material that fills the clearance, and the holding material is Characterized in that it is composed of a material disengaged from the clearance from the relative rotation between the cam shaft and the rotation transmitting member.

  According to the present invention, since the clearance formed between the inner peripheral surface of the shaft hole of the rotation transmitting member and the outer peripheral surface of the camshaft inserted through the shaft hole is filled with the holding material, the clearance is reduced. The output member of the variable valve timing mechanism is fastened and fixed to one end of the camshaft by a fastening member while being securely held, and therefore the rotation center axis of the rotation transmission member, the camshaft and the output member is arranged coaxially. Thus, the variable valve mechanism assembled in the above state can be obtained. When the internal combustion engine is operated, the rotation transmission member of the variable valve timing mechanism and the camshaft are relatively rotated to adjust the phase, so that the holding material is the inner peripheral surface of the shaft hole of the rotation transmission member And the camshaft from the outer peripheral surface of the camshaft and depart from the clearance, so that a variable valve mechanism that does not prevent the camshaft from rotating relative to the rotation transmission member of the variable valve timing mechanism can be obtained. it can.

It is sectional drawing shown roughly in order to demonstrate one Embodiment of the variable valve mechanism of this invention. It is sectional drawing shown roughly in order to demonstrate the structure of the conventional general variable valve mechanism.

  An embodiment of a variable valve mechanism according to the present invention will be described in detail with reference to FIG. In the following description, the same components or corresponding components are denoted by the same reference numerals.

  FIG. 1 shows a case where the rotation transmission member is a sprocket 1 and the output member of the variable valve timing mechanism 3 is a cam gear 3 as an embodiment.

  A timing chain is wound between the sprocket 1 and a sprocket provided on the output shaft of the internal combustion engine, and is driven to rotate by receiving the power of the output shaft of the internal combustion engine. A shaft hole 10 through which the camshaft is inserted is formed at the center of the sprocket 1. Further, the sprocket 1 is formed with a recess 11 for accommodating the cam gear 30.

  Each cylinder of the internal combustion engine is provided with an intake valve and an exhaust valve on the same side, and the camshaft 2 is provided on the intake valve side and the exhaust valve side. Only one of the intake side and the exhaust side of the camshaft 2 of the embodiment shown in FIG. 1 is shown. The variable valve mechanism according to the present invention can include a configuration in which sprockets 1 are provided on both the intake-side camshaft 2 and the exhaust-side camshaft 2 and a timing chain is wound around the intake-side camshaft 2. A sprocket 1 is provided on only one of the camshaft and the exhaust camshaft 2, a timing chain is wound around the sprocket 1, and both the camshafts 2 and 2 are gear-connected to provide the sprocket 1. The structure which receives the motive power of an internal combustion engine with the camshaft 2 of one side, and rotates both the camshafts 2 which were gear-connected can be included. The camshaft 2 may drive both the intake valve and the exhaust valve. Further, the rotation transmission member 1 in the present invention is not limited to a sprocket, and is provided on a pulley in which a timing belt is wound around a pulley provided on an output shaft of the internal combustion engine, or on an output shaft of the internal combustion engine. It is also possible to use a gear that is meshed with a gear that is engaged with a timing gear.

  The variable valve timing mechanism 3 shown in FIG. 1 is constituted by a planetary gear mechanism controlled by an electric motor. The planetary gear mechanism is provided between the cam gear 30 as an output member fastened to one end of the camshaft 2 by the center bolt 5, the gear sprocket 31 coupled to the sprocket 1, and the cam gear 30 and the gear sprocket 31. A planetary gear 32 and an eccentric shaft 33 connected to the planetary gear 32 and driven by an electric motor are included. The outer diameter of the cam gear 30 is set slightly smaller than the inner diameter of the concave portion 11 of the sprocket 1, and a clearance 8 is formed between the outer peripheral surface of the cam gear 30 and the inner peripheral surface of the concave portion 11 of the sprocket 1. ing.

  The fastening member in the embodiment shown in FIG. The shaft portion of the center bolt 5 is inserted into the center hole 35 of the cam gear 30 and is in the shaft portion with respect to the female screw hole 20 formed at the center of one end surface of the cam shaft 2 so as to extend in the axial direction of the cam shaft 2. The formed male screw part 50 is screwed together. The camshaft 2 is inserted into the shaft hole 10 of the sprocket 1, and the center bolt 5 is inserted into the center hole 35 of the cam gear 30 and fastened to the female screw hole 20 of the camshaft 2, whereby the sprocket 1 and the camshaft 2 are variable. The central axis of rotation of the valve timing mechanism 3 and the cam gear 30 is coaxially arranged.

  The inner diameter of the shaft hole 10 of the sprocket 1 is set slightly larger than the outer diameter of the camshaft 2. Therefore, a clearance 6 is formed between the inner peripheral surface of the shaft hole 10 of the sprocket 1 and the outer peripheral surface of the camshaft 2. Further, the outer diameter of the shaft portion of the center bolt 5 is set slightly smaller than the inner diameter of the center hole 35 of the cam gear 30. for that reason. A clearance 9 is formed between the outer peripheral surface of the shaft portion of the center bolt 5 and the inner peripheral surface of the center hole 35 of the cam gear 30.

  When the variable valve mechanism of the present embodiment is assembled, the clearance 6 formed between the inner peripheral surface of the shaft hole 10 of the sprocket 1 and the outer peripheral surface of the camshaft 2 is filled with the holding material 7. It has been. The holding material 7 can be made of, for example, a synthetic resin that has fluidity when applied, and is solidified by elapse of time, drying or baking. The holding member 7 is made of a material that is peeled off from the clearance 6 by the relative rotation between the sprocket 1 and the camshaft 2.

  As long as the variable valve timing mechanism 3 has an output member corresponding to the cam gear 30, the variable valve timing mechanism 3 is not limited to the one controlled by the electric motor as described above. For example, the variable valve timing mechanism 3 is a vane rotor controlled by hydraulic pressure. It is possible to employ a variable valve timing mechanism having a known configuration, such as one having a helical spline or one having a helical spline.

  Further, the fastening member 5 extends in the axial direction of the camshaft 2 at the center of one end surface of the camshaft 2, protrudes so as to be inserted into the center hole 35 of the cam gear 30, and has a shaft portion on which a male screw portion is formed. And it can also be comprised by the nut screwed together by the external thread part of this axial part.

  When the internal combustion engine having the variable valve mechanism configured as described above is operated, the sprocket 1 and the camshaft 2 are relatively rotated by the variable valve timing mechanism 3 to adjust the rotation phase. As a result, the holding material 7 filling the clearance 6 between the inner peripheral surface of the shaft hole 10 of the sprocket 1 and the outer peripheral surface of the camshaft 2 is peeled, separated from the clearance 6 and discharged outside. Therefore, the holding material 7 does not hinder the relative rotation between the sprocket 1 and the camshaft 2.

  Next, a method for assembling the variable valve mechanism having the above-described configuration will be described. The method generally includes a rotation transmission member 1 that is driven to rotate by receiving the power of an output shaft of an internal combustion engine, and a camshaft provided with a cam for opening and closing one of an intake valve and an exhaust valve of the internal combustion engine. 2 and a variable valve timing mechanism 3 that outputs the rotational driving force input from the rotational transmission member 1 to the camshaft 2 and adjusts the rotational phase between the rotational transmission member 1 and the camshaft 2, and includes the rotational transmission member. 1, a camshaft 2 is inserted into a shaft hole 10 formed in the center thereof, and a variable valve timing mechanism 3 is output at one end of the camshaft 2 by a fastening member 5 coaxially with the camshaft 2. It is for assembling a variable valve mechanism having a member 30 and is made of a material that is separated from the clearance by the relative rotation of the rotation transmitting member 1 and the camshaft 2. The holding member 7 thus formed is attached to at least one of the inner peripheral surface of the shaft hole 10 of the rotation transmission member 1 and the outer peripheral surface of the cam shaft 2, and the cam shaft 2 is inserted into the shaft hole 10 of the rotation transmission member 1. At this time, the output member 30 of the variable valve timing mechanism 3 is fastened to one end of the camshaft 2 by the fastening member 5 in a state where the clearance 6 is filled with the holding material 7.

  In this embodiment, prior to assembling the variable valve mechanism, the holding material 7 having fluidity is applied to the inner peripheral surface of the shaft hole 10 of the sprocket 1 that is a rotation transmitting member and solidified. In order to solidify the holding material 7, there is no particular limitation on the chemical reaction caused by the passage of time, heating or baking, addition of a solidifying agent, or the like depending on the material of the holding material 7. it can. Further, the target to which the holding material 7 is applied may be the outer peripheral surface of the camshaft 2, or may be applied to both the inner peripheral surface of the shaft hole 10 of the rotation transmitting member 1 and the outer peripheral surface of the camshaft 2. .

  After the holding material 7 is solidified, the camshaft 2 is inserted into the shaft hole 10 of the sprocket 1. At this time, the holding material 7 applied and solidified on the inner peripheral surface of the shaft hole 10 of the sprocket 1 fills the clearance 6 between the outer peripheral surface of the camshaft 2. In this state, the shaft portion of the center bolt 5 is inserted into the center hole 35 of the output member 30, the output member 30 is inserted into the recess 11 of the sprocket 1, and the female screw hole 20 formed on one end surface of the camshaft 2 is inserted. The male screw part 50 of the center bolt 5 is screwed and fastened. Then, a gear sprocket 31, a planetary gear 32, an eccentric shaft 33, and the like, which are other components of the variable valve timing mechanism 3, are assembled to the sprocket 1 and the output member 30.

The gap between the inner peripheral surface of the shaft hole 10 of the sprocket 1 and the outer peripheral surface of the camshaft 2 is filled with a holding material 7 so that the clearance 6 between the sprocket 1 and the camshaft 2 is accurately held by the center bolt 5 to output members 30 can be fastened to one end of the camshaft 2. Therefore, the rotation center axis of the cam gear 30 does not shift from the rotation center axis of the camshaft 2 due to the reaction force that rotates the center bolt 5 around the axis. Therefore, the rotation center axis of the sprocket 1 is not the rotation center axis of the camshaft 2. Since the center of rotation of the sprocket 1, the camshaft 2 and the output member 30 is accurately and easily aligned, components other than the output member 30 of the variable valve timing mechanism 3 are assembled. be able to. As a result, the inner peripheral surface of the shaft hole 10 of the sprocket 1 does not interfere with the outer peripheral surface of the camshaft 2,
The variable valve timing mechanism 3 can prevent friction when the camshaft 2 rotates relative to the sprocket 1, and the variable valve timing mechanism 3 can adjust the rotation phase of the camshaft 2 relative to the sprocket 1. Can eliminate the possibility of affecting

  The variable valve mechanism is assembled by inserting the camshaft 2 through the shaft hole 10 of the rotation transmitting member 1 and then solidifying the holding material 7 before applying and solidifying the holding material 7. The holding member 7 is inserted between the shaft hole 10 of the rotation transmission member 1 and the outer peripheral surface of the cam shaft 2 after the camshaft 2 is inserted into the shaft hole 10 of the rotation transmission member 1. It can also be included that the holding material 7 is then solidified.

  1: sprocket (rotation transmission member), 2: camshaft, 3: variable valve timing mechanism, 10: shaft hole, 30: output member, 5: center bolt (fastening member), 6: inner peripheral surface of shaft hole of sprocket Between the outer periphery of the camshaft and the camshaft 7

Claims (1)

A rotation transmission member that is driven to rotate by receiving the power of the output shaft of the internal combustion engine;
A camshaft provided with a cam for opening and closing at least one of an intake valve and an exhaust valve of the internal combustion engine;
A variable valve timing mechanism that outputs a rotational driving force input from the rotation transmission member to the camshaft and adjusts a rotation phase between the rotation transmission member and the camshaft;
The rotation transmitting member is inserted in a state where the camshaft has a clearance in a shaft hole formed at the center thereof,
The variable valve timing mechanism is a variable valve mechanism having an output member that is fastened to one end of the camshaft by a fastening member coaxially with the camshaft.
And a holding member that fills the clearance. The holding member is made of a material that is separated from the clearance by relative rotation between the rotation transmission member and the camshaft. Valve mechanism.

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