JP2008025428A - Engine with cam phase variable device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine with a VTC device capable of reducing a dimension in the camshaft direction. <P>SOLUTION: This engine E is formed by arranging the VTC device 6 for changing a phase of a camshaft to a phase of a crankshaft between the camshaft (an intake camshaft 1) supported by a cam holder 12 and a cam sprocket 11 transmitting torque of the crankshaft 9 to the camshaft. The VTC device has an inner rotor 23 fixed to a projecting part from the cam holder in the camshaft, and an outer rotor 21 rotatably receiving the inner rotor in a predetermined angle range and integrated with the cam sprocket. A projection part 25a is formed on a cam holder side surface of the outer rotor. A recessed part 42 corresponding to the projection part is formed in a position opposed to the projection part in an outer rotor side surface of the cam holder. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine provided with a cam phase varying device for changing a mutual relationship between rotation angles (phases) of a crankshaft and a camshaft.

By combining an outer rotor integrally connected to a cam sprocket that is interlocked with a crankshaft and a chain, and an inner rotor integrally connected to the camshaft so that a predetermined angle range can be relatively rotated, the crankshaft and cam A cam phase variable (Variable Timing Control: hereinafter abbreviated as VTC) device in which the phase relationship with the shaft is changed has already been put into practical use (see Patent Document 1). In this VTC device, an inner rotor is fixed to the shaft end of the camshaft, and an inner rotor connecting portion of the camshaft is rotatably supported in a bearing hole provided in one axial end wall of the outer rotor.
JP 2002-295290 A

  However, the camshaft is supported by a cam holder fixed to the cylinder head. In order to avoid interference between the axial end surfaces of the outer rotor of the VTC device that is a rotating body and the cam holder that is a fixed body, the camshaft is separated from the end surface of the cam holder. It is necessary to dispose the outer rotor separately.

  On the other hand, the bearing hole in the axial end wall of the outer rotor increases the axial dimension of the portion of the camshaft through which the inner rotor connecting portion is inserted in order to suppress the outflow of engine oil sealed between the outer rotor and the inner rotor. There is a need. Also, the cam holder cannot have a very small axial dimension for the purpose of forming a hole through which a bolt for fastening the cam holder to the cylinder head and an oil passage through which engine oil flows. And when it designed so that these conditions might be satisfy | filled, the protrusion amount of the VTC apparatus from the end surface of a cam holder had to become large, and, for this reason, the engine full length had to be increased.

  The present invention has been devised to solve such problems of the prior art, and a main object of the present invention is to provide an engine with a VTC device that can reduce the cam axial dimension.

In order to solve such problems, the present invention provides a crankshaft between a camshaft (intake camshaft 1) supported by a cam holder 12 and a cam sprocket 11 that transmits the rotational force of the crankshaft 9 to the camshaft. In order to change the phase of the camshaft with respect to the phase of the shaft, the inner rotor 23 fixed to the projecting portion of the camshaft from the cam holder, the inner rotor is rotatably received within a predetermined angular range, and is integrated with the cam sprocket. In the engine E provided with the VTC device 6 having the outer rotor 21, the convex portion 25a is formed on the cam holder side surface of the outer rotor, and the convex portion corresponds to the convex portion on the outer rotor side surface of the cam holder. The recess 42 is formed (claim 1).
In the engine with the VTC device having the above-described configuration, an annular recess 42 is provided around the camshaft insertion hole (bearing hole 14) on the outer rotor side surface of the cam holder, and at least a part of the outer rotor (projection 25a) is a recess. (Claim 2).
Further, in the engine with the VTC device having the above-described configuration, an annular convex portion 25a protruding toward the cam holder is provided on the bearing portion of the outer rotor, and the cam shaft insertion hole (bearing hole 14) is provided on the outer rotor side surface of the cam holder. An annular concave portion 42 corresponding to the convex portion is provided on the inner surface (claim 3).
In particular, it is preferable to provide at least one of an oil passage or a bolt hole on the radially outer side of the recess in the cam holder.

According to such a configuration of claims 1 to 3 of the present invention, the outer rotor can be brought closer to the cam holder side while securing the axial dimension of the camshaft insertion hole, so the cam axial dimension of the engine is reduced. Thus, it is possible to achieve a great effect in improving engine mountability on the vehicle body.
In particular, according to the configuration of the third aspect, it is only necessary to provide the concave portion of the cam holder in the minimum region while increasing the bearing rigidity of the outer rotor, so that a decrease in the rigidity of the cam holder can be suppressed.
According to the fourth aspect of the present invention, since the oil passage or the bolt hole can be provided without increasing the axial dimension of the cam holder, it can contribute to further reduction of the cam axial dimension of the engine.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows an in-line four-cylinder DOHC engine to which the present invention is applied. The cylinder head of the engine E is provided with two intake valves 2 driven by the intake camshaft 1 and two exhaust valves 4 driven by the exhaust camshaft 3 for each of the four cylinders. .

  A VTC device 6 for advancing or retarding the opening / closing timing of the intake valve 2 steplessly is provided at the shaft end of the intake camshaft 1.

  The intake camshaft 1 and the exhaust camshaft 3 are interlocked and connected via a chain / sprocket mechanism 10 to a crankshaft 9 to which four pistons 8 are connected via a connecting rod 7. Is rotated at a rotational speed of ½ of that.

  Next, the VTC device 6 provided at the shaft end of the intake camshaft 1 will be described with reference to FIGS. The VTC device 6 is for continuously changing the phase of the intake camshaft 1 with respect to the phase of the crankshaft 9 of the engine E by a predetermined angle, and transmits the driving force of the crankshaft 9 to the intake camshaft 3. For this purpose, it is provided between the cam sprocket 11 and the intake camshaft 9.

  The VTC device 6 is provided at a protruding portion from the cam holder 12 in the intake camshaft 1 supported by a cam holder 12 fixed to a cylinder head (not shown), and is integrated with a cam sprocket 11 around which a timing chain is wound. The outer rotor 21 is combined with the inner rotor 23 that is integrally connected to the intake camshaft 1 with bolts 22.

  The outer rotor 21 has a cup body 21a formed in a substantially bottomed cylindrical shape, a vane housing 21b received inside the cup body 21a, and a cam sprocket 11 integrally formed on the outer periphery thereof, and is formed on the opening end surface of the cup body 21a. The sprocket disks 21c are joined together, and these are integrally connected to each other with a plurality of bolts 24. Then, the shaft end of the intake camshaft 1 is inserted into a bearing hole 26 formed at the center of the bottom wall 25 of the cup body 21a, and the inner rotor 23 integrated with the intake camshaft 1 has a predetermined angle range in the vane housing 21b. It is received so as to be capable of rotational displacement.

  On the inner periphery of the vane housing 21b, a plurality (four in this embodiment) of fan-shaped recesses 27 concentric with the intake camshaft 1 are formed. A plurality of (four in the present embodiment) vanes 28 projecting radially from the outer periphery of the inner rotor 23 are received in each sector-shaped recess 27 so as to be able to rotate within a predetermined angular range. Thereby, the advance chamber 29 is provided between one circumferential end surface of each vane 28 and each sector-shaped recess 27, and the retard angle is provided between the other circumferential end surface of each vane 28 and the sector-shaped recess 27. Each chamber 30 is defined.

  A seal member 31 is provided on the outer peripheral surface of each vane 28 so as to be in sliding contact with the inner peripheral surface of the corresponding sector-shaped recess 27. Further, four seal members 32 that are in sliding contact with the outer peripheral surface of the inner rotor 23 are provided on the inner peripheral surface of the vane housing 21b.

  Oil passages (not shown) communicating with each advance chamber 29 and each retard chamber 30 are formed inside the intake camshaft 1, the inner rotor 23 and the cam holder 12. By selectively supplying the corner chambers 29 and the respective retard chambers 30 using a known spool valve or the like, the vane 28 is moved in the fan-shaped recess 27 to change the relative angle between the outer rotor 21 and the inner rotor 23. Thus, the phase of the intake camshaft 1 with respect to the phase of the crankshaft 9 is changed.

  Since this VTC device 6 is already well known and its operation procedure is irrelevant to the essence of the present invention, further explanation is omitted here (see Patent Document 1 if necessary).

  In the VTC device 6 configured as described above, it is desirable that the VTC device 6 can be disposed as close to the cam holder 12 as possible in order to suppress an increase in engine size. However, when the VTC device 6 is simply pushed inward in the axial direction, the bottom wall 25 of the cup body 21a interferes with the cam holder 12, so that at least one of the cam holder 12 and the bottom wall 25 of the cup body 21a is moved. If the thickness is reduced, the protruding amount of the VCT apparatus 6 can be reduced. However, the cam holder 12 is provided with holes 41 for inserting fastening bolts for fixing the cam holder 12 to the cylinder head or for oil passages through which engine oil flows, and portions corresponding to these holes 41. There is a limit to reducing the thickness. Further, the bearing hole 26 provided in the bottom wall 25 of the cup body 21a is in sliding contact with the connecting portion of the inner rotor 23 in the intake camshaft 1 and needs to support the chain tension applied to the cam sprocket 11. There is a limit to making the bottom wall 25 of the cup body 21a thin in order to suppress the surface pressure of the surface.

  Therefore, in the present invention, the bottom wall 25 of the cup body 21a is made thinner on the outer peripheral side than the inner peripheral side to form the axial convex portion 25a projecting toward the cam holder 12 around the bearing hole 26, and at the same time, 12, an annular recess 42 is formed around the bearing hole 14 that supports the journal portion 13 of the intake camshaft 1 on the surface facing the bottom wall 25 of the cup body 21 a. And the part of the inner peripheral side of the bottom wall 25 of the cup body 21a, ie, the axial direction convex part 25a shall be immersed in this annular recessed part 42. As shown in FIG. In this way, the axial dimension of the bearing hole 26 that supports the connection portion of the intake camshaft 1 with the inner rotor 23 is secured, and the VTC device 6 is pushed inwardly to the maximum on the axis of the intake camshaft 1. Thereby, suppression of the protrusion amount from the engine main body of the VTC apparatus 6 is aimed at.

  Further, the hole 41 for inserting the oil passage and the bolt is provided outside the annular recess 42 in the cam holder 12 in the radial direction, thereby suppressing an increase in the axial dimension of the cam holder 12.

  An oil passage 43 is formed in the intake camshaft 1 so that a part of the engine oil flows through the bearing hole 26 and the journal portion 13 of the bottom wall 25 of the cup body 21a and is lubricated. When the flow rate from the oil passage 43 is large, the amount of oil for operating the VTC device 6 decreases, and there is a concern that the operation responsiveness of the VTC device 6 may decrease. Therefore, in order to prevent such inconvenience, it is preferable to provide a bearing 44 with a seal in the intake camshaft bearing hole 14 in the cam holder 12 as shown in FIG.

1 is a schematic transparent perspective view of an engine to which the present invention is applied. It is a horizontal sectional view in alignment with the II-II line in FIG. 3 of the attaching part of this invention apparatus. It is a vertical sectional view of the device of the present invention. It is a horizontal sectional view which shows another form of the attaching part of this invention apparatus.

Explanation of symbols

E engine 1 intake camshaft 6 VTC device 9 crankshaft 11 cam sprocket 12 cam holder 21 outer rotor 23 inner rotor 25a convex portion 42 annular concave portion

Claims (4)

A cam phase varying device for changing the phase of the camshaft relative to the phase of the crankshaft is provided between a camshaft supported by the cam holder and a cam sprocket that transmits the rotational force of the crankshaft to the camshaft. Engine,
The cam phase varying device includes an inner rotor fixed to a protruding portion of the camshaft from the cam holder, and an outer rotor that rotatably receives the inner rotor within a predetermined angular range and is integrated with the cam sprocket. And
While forming a convex portion on the surface of the outer rotor on the cam holder side,
An engine with a cam phase varying device, wherein a concave portion corresponding to the convex portion is formed at a position facing the convex portion on the outer rotor side surface of the cam holder. A cam phase varying device for changing the phase of the camshaft relative to the phase of the crankshaft is provided between a camshaft supported by the cam holder and a cam sprocket that transmits the rotational force of the crankshaft to the camshaft. Engine,
The cam phase varying device includes an inner rotor fixed to a protrusion of the camshaft from the cam holder, and an outer rotor that rotatably receives the inner rotor within a predetermined angle range and that is integral with the cam sprocket. And
An annular recess is provided around the camshaft insertion hole on the outer rotor side surface of the cam holder,
An engine with a cam phase varying device, wherein at least a part of the outer rotor is immersed in the recess. A cam phase varying device for changing the phase of the camshaft relative to the phase of the crankshaft is provided between a camshaft supported by the cam holder and a cam sprocket that transmits the rotational force of the crankshaft to the camshaft. Engine,
The cam phase varying device includes an inner rotor fixed to a protrusion of the camshaft from the cam holder, and an outer rotor that rotatably receives the inner rotor within a predetermined angle range and that is integral with the cam sprocket. And
While providing an annular convex portion protruding toward the cam holder on the bearing portion of the outer rotor,
An engine with a cam phase varying device, wherein an annular recess corresponding to the protrusion is provided around a cam shaft insertion hole on a surface of the cam holder on the outer rotor side.   The engine with a cam phase varying device according to any one of claims 1 to 3, wherein at least one of an oil passage and a bolt hole is provided on a radially outer side of the concave portion in the cam holder.

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