WO2018168302A1 - Variable valve device for internal combustion engine - Google Patents

Abstract

Provided is a variable valve device comprising: a hollow outer camshaft 5 having a first drive cam 7 on the outer periphery thereof; and an inner camshaft 6 disposed in a relatively rotatable manner within the outer camshaft and having a second drive cam 11 on the outer periphery thereof. The rear plate 15 of a housing 2 has a first fitting hole 20 into which a first shaft section 5a of the outer camshaft is inserted and fitted. A vane rotor 3 has a second fitting hole 21 in a rotor 17, the second fitting hole 21 allowing the first shaft section to be inserted and fitted therein. The outer camshaft holds the housing 2 and the vane rotor 3 so that the housing 2 and the vane rotor 3 are coaxial with each other. As a result the outer camshaft, for example, alone is capable of centering the housing and the vane rotor, so the coaxial relationship between the housing and the vane rotor is not affected.

Description

Variable valve operating device for internal combustion engine

The present invention relates to a variable valve operating apparatus for an internal combustion engine that variably controls the operation characteristics of the engine valve of the internal combustion engine.

As a conventional variable valve operating device, for example, one described in Patent Document 1 below is known.

This variable valve operating apparatus is provided with two intake valves per cylinder, an inner cam shaft in which an inner cam for driving one intake valve is integrally provided on the outer periphery, and relative rotation on the outer periphery of the inner cam shaft And an outer camshaft that is integrally provided with an outer cam that drives the other intake valve.

A hydraulic actuator including a valve timing control device is provided at each end of the inner cam shaft and the outer cam shaft.

This hydraulic actuator has a stator and a rotor that can rotate relative to the stator, and an outer cam shaft is inserted and fixed to the stator, while an inner cam shaft is inserted and fixed to the rotor. .

The hydraulic actuator controls the operating angle and opening / closing timing of each intake valve by relatively rotating the inner cam shaft and the outer cam shaft by the supplied hydraulic pressure.

Japanese translation of PCT publication No. 2010-502884

However, in the variable valve operating apparatus described in Patent Document 1, as described above, the stator and the rotor are inserted and fixed to the outer cam shaft and the inner cam shaft, respectively. For this reason, when an axial misalignment occurs between the inner cam shaft and the outer cam shaft, the coaxiality between the stator and the rotor may be affected. As a result, the rotational behavior of each camshaft becomes unstable, which may lead to instability of the operating characteristics of the intake valve.

An object of the present invention is to provide a variable valve apparatus that can suppress the influence on the coaxiality of the first rotating body and the second rotating body.

As a preferable aspect of the present invention, a first shaft portion extending from one of the outer cam shaft and the inner cam shaft has a first fitting hole into which the first shaft portion is inserted and fitted, and is fixed to the outer cam shaft. A rotating body, and a second rotating body that is disposed inside the first rotating body, has a second fitting hole into which the first shaft portion is inserted and fitted, and is fixed to the inner camshaft. It is characterized by having.

According to a preferred aspect of the present invention, the influence on the coaxiality of the first rotating body and the second rotating body can be suppressed.

It is a perspective view which decomposes | disassembles and shows the principal part of 1st Embodiment of the variable valve apparatus which concerns on this invention. FIG. 7 is a cross-sectional view taken along line AA of FIG. 6 showing the present embodiment. It is a right view of the variable valve apparatus of this embodiment. It is a perspective view which shows the state which removed the sensor target of the variable valve apparatus of this embodiment. It is action | operation explanatory drawing which shows the state which rotated the vane rotor in the same embodiment to the maximum relative to one direction. It is an effect explanatory view showing the state where the vane rotor in the embodiment was relatively rotated to the maximum in the other direction. FIG. 7 is a cross-sectional view taken along line BB of FIG. 6 showing a lock mechanism provided for the present embodiment. The first and second drive cams used in this embodiment are shown, A shows the state where both drive cams have the same rotation phase, and B shows the second drive cam changing the rotation phase with respect to the first drive cam. Shows the state. The lift characteristic diagram of the intake valve in the present embodiment is shown, A is a lift characteristic diagram in the case of relative rotation in the maximum one direction shown in FIG. 6, B is a lift characteristic diagram in the case of relative rotation in the maximum other direction shown in FIG. It is. FIG. 7 is a sectional view taken along line AA of FIG. 6 showing a second embodiment of the variable valve operating apparatus of the present invention. FIG. 7 is a sectional view taken along line AA of FIG. 6 showing a third embodiment of the variable valve operating apparatus of the present invention. FIG. 7 is a sectional view taken along line AA of FIG. 6 showing a fourth embodiment of the variable valve operating apparatus of the present invention.

Embodiments of a variable valve operating apparatus for an internal combustion engine according to the present invention will be described below with reference to the drawings. In this embodiment, a gasoline specification, for example, applied to the intake valve side of a four-cylinder internal combustion engine is shown.
[First Embodiment]
FIG. 1 is an exploded perspective view showing an essential part of a first embodiment of a variable valve operating apparatus according to the present invention, FIG. 2 is a cross-sectional view taken along line AA of FIG. 6, and FIG. FIG. 4 is a perspective view showing a state in which the sensor target of the variable valve operating device is removed, and FIGS. 5 and 6 are states in which the vane rotor in the embodiment is relatively rotated in one direction and the other direction to the maximum. FIG.

The internal combustion engine has two intake valves per cylinder, and at least one of the two intake valves is provided with a variable valve gear. That is, in this embodiment, the variable valve operating device variably controls the operating angle of the intake valve in accordance with the engine operating state. Here, the operating angle refers to the open period from when the intake valve is opened to when it is closed.

More specifically, as shown in FIGS. 1 and 2, the variable valve operating apparatus includes a camshaft 1 having an inner and outer double outer camshaft 5 and an inner camshaft 6, and rotation of the camshaft 1. A housing 2 that is a first rotating body provided at one end in the axial direction, a vane rotor 3 that is a second rotating body housed in the housing 2 so as to be relatively rotatable, and the housing 2 and the vane rotor 3 And a hydraulic circuit 4 that controls the relative rotational positions of the camshafts 1 and 3.

Further, a valve timing control device (not shown) is provided on the other end portion side in the rotation axis direction of the camshaft 1 (the outer camshaft 5 and the inner camshaft 6). The valve timing control device includes a sprocket that is rotationally driven via a timing chain by a crankshaft (not shown) of the engine, the camshaft 1 that is provided to be rotatable relative to the sprocket, and the sprocket and camshaft. 1 and a phase conversion mechanism that converts the relative rotational phase of the two and a hydraulic circuit that operates the phase conversion mechanism. A specific description of this valve timing control device is omitted.

The two intake valves per cylinder are designed so that each umbrella portion opens and closes the open ends on the cylinder side of the two intake ports (not shown). Further, each intake valve is urged in the closing direction by the spring force of the valve spring via a valve lifter disposed at the upper end of each intake valve.

The outer camshaft 5 is formed in a hollow shape inside and is rotatably supported by a cylinder head (not shown) via a cam bearing. The outer cam shaft 5 is integrally fixed to a predetermined position on the outer peripheral surface by press-fitting a first drive cam 7 that is an outer cam that opens the intake valve on one side of each cylinder via a valve lifter.

Further, the outer camshaft 5 integrally has a first shaft portion 5a facing the inside of the housing 2 at one end portion in the rotation axis direction.

The outer camshaft 5 has a flange portion 8 integrally fixed to one end portion on the first shaft portion 5a side. The flange portion 8 is formed in a disk shape from an iron-based metal that is a metal material, and is fixed to the outer peripheral surface of the outer camshaft 5 by shrink fitting through an insertion hole 8a penetratingly formed in the center. Further, in the outer peripheral portion of the flange portion 8, three bolt insertion holes 8 b into which a plurality of (three in the present embodiment) fastening bolts 9 as fixing means for the rear plate 15 described later are inserted are formed. Further, the flange portion 8 is formed to have an outer diameter substantially the same as that of the rear plate 15 and is thinner than the rear plate 15 in order to reduce the thickness.

In addition, a pin 8c for positioning in the circumferential direction with the rear plate 15 is provided on the outer peripheral portion of the flange portion 8 so as to protrude toward the rear plate 15 side.

The inner cam shaft 6 is basically formed in a solid shape, and is rotatably supported on the inner peripheral surface of the outer cam shaft 5. Further, the inner camshaft 6 integrally has a second shaft portion 6a facing the inside of the housing 2 at one end portion in the rotation axis direction. The second shaft portion 6 a slightly protrudes from one end opening of the first shaft portion 5 a of the outer cam shaft 5.

The inner camshaft 6 has an insertion hole into which the cam bolt 10 is inserted in the direction of the internal shaft on the second shaft portion 6a side. A female screw hole (not shown) into which a male screw 10c formed on the outer peripheral tip side of the shaft portion 10b of the cam bolt 10 is screwed is formed on the inner tip side of the insertion hole.

At a predetermined position in the axial direction of the inner camshaft 6, the second drive cam 11 is an inner cam that opens the intake valve on one side through the same valve lifter while sliding on the outer peripheral surface of the outer camshaft 5. Is fixed.

The second drive cam 11 is fixed to the inner camshaft 6 by a connecting shaft 12 inserted through a through hole formed in a diameter direction passing through the center of the rotation axis of the inner camshaft 6. The connecting shaft 12 is configured to fix the second drive cam 11 to the inner cam shaft 6 by press-fitting and fixing both ends 12 a and 12 b inside the second drive cam 11. Further, the connecting shaft 12 passes through a pair of insertion holes 12 c and 12 d formed so as to penetrate in the diameter direction of the outer camshaft 5. Both the insertion holes 12 c and 12 d are formed in a slit shape along the circumferential direction of the outer cam shaft 5, and the second drive cam 11 is connected to the first drive cam 7 through a predetermined angle range via the connecting shaft 12. It is designed to allow relative rotation.

The first drive cam 7 and the second drive cam 11 are arranged adjacent to each other with a slight gap between them. Further, the outer peripheral surfaces 7a and 11a are formed in the same egg-shaped cam profile so that one intake valve in one cylinder is opened and closed independently.

The housing 2 includes a cylindrical housing main body 13 that is open at both ends in the axial direction, a front plate 14 that closes the openings at the front and rear ends of the housing main body 13 in the axial direction, and a rear plate 15. Further, the front plate 14 and the rear plate 15 are integrally coupled to the housing body 13 from the axial direction by the axial force of a plurality (five in this embodiment) of bolts 16.

The housing body 13 is integrally formed of a metal material formed by, for example, a sintering method, and has five first to third shoes 13a to 13e on the inner peripheral surface as shown in FIGS. Projecting inward.

Each of the shoes 13a to 13e is formed in a substantially trapezoidal shape when viewed from the side, and is disposed at a position of approximately 180 ° in the circumferential direction of the housing body 13 and one at a position therebetween. The substantially U-shaped seal members 19 are fitted and fixed in seal grooves formed along the axial direction.

Further, five bolt insertion holes 13i through which the bolts 16 are inserted are formed through the radially outer peripheral sides of the shoes 13a to 13e.

The first shoe 13a has a flat first convex surface 13f formed on one side surface in the circumferential direction. On the other hand, the second shoe 13b has a second convex surface 13g that is also flat on one side surface that faces the one side surface of the first shoe 13a in the circumferential direction. As shown in FIGS. 5 and 6, the convex surfaces 13 f and 13 g are formed so that the respective side surfaces facing each other when the vane rotor 3 rotates counterclockwise (leftward in the figure) or clockwise (rightward in the figure). Abut. Thus, the vane rotor 3 is restricted to the maximum rotational position in the left-right direction in the drawing.

The front plate 14 is formed into a relatively thin disk by pressing a metal plate. In addition, a through hole 14a into which a shaft portion 10b of the cam bolt 10 and a target member 35 of a later-described rotation detection mechanism are inserted is formed in the center of the front plate 14. Further, five bolt insertion holes 14b through which the respective bolts 16 are inserted are formed in the circumferentially equidistant positions on the outer peripheral side.

The rear plate 15 is formed of a metal material formed by sintering as is the case with the housing body 13, and is formed in a thick disk shape also with the front plate 14. In addition, the rear plate 15 has a first fitting hole 20 which is a first insertion hole into which the first shaft portion 5a of the outer camshaft 5 is inserted at the center.

The first fitting hole 20 has an inner diameter slightly larger than the outer diameter of the first shaft portion 5a of the outer camshaft 5, and the first shaft portion 5a is inserted tightly and accurately. That is, the outer peripheral surface of the first shaft portion 5a and the inner peripheral surface of the first fitting hole 20 are closely fitted so as to be close to press-fitting without a gap.

Also, at the circumferentially equidistant positions on the outer peripheral side of the rear plate 15, five female screw holes 15 b into which the male screws 16 b at the tip of the shaft portion 16 a of each bolt 16 are screwed are formed.

Furthermore, at a predetermined position on the outer peripheral portion of the rear plate 15, there is provided a fixing hole 15c into which a lock hole constituting portion 31 that forms a lock hole 31a that is a lock recess of the lock mechanism 28 described later is press-fitted. As will be described later, the lock hole 31a is adapted to engage with a lock pin 30 that is a lock member of the lock mechanism 28 at the maximum counterclockwise position of the vane rotor 3.

Further, three female screw holes 15e into which three fastening bolts 9 are screwed are formed on the outer surface of the outer peripheral portion of the rear plate 15 on the flange portion 8 side.

A positioning pin 15d that engages with a positioning groove 13h formed on the outer peripheral surface of the first shoe 13a of the housing main body 13 to position the housing main body 13 is provided at a predetermined position on the outer peripheral portion of the rear plate 15. Protrusively provided. Further, the rear plate 15 is formed with a positioning hole (not shown) in which the positioning pin 8c of the flange portion 8 is engaged and positioned on the outer surface opposite to the pin 15d.

The vane rotor 3 is integrally formed of a metal material formed by sintering. As shown in FIGS. 1 and 5, the rotor 17 on the center side and a plurality of protrusions projecting radially from the outer periphery of the rotor 17 are provided. The first to fifth vanes 18a to 18e (five in this embodiment) are configured.

The rotor 17 is formed in a substantially cylindrical shape as a whole, and is formed in a stepped diameter shape having a large and small outer diameter, and a passage forming hole 17a into which the shaft portion 10b of the cam bolt 10 is inserted is formed in the center. Yes. In addition, the rotor 17 has a circular insertion groove 17b into which the target member 35 is inserted at the center position of the outer surface of the cam bolt 10 on the head 10a side.

The passage constituting hole 17 a is formed with a larger inner diameter than the outer diameter of the shaft portion 10 b of the cam bolt 10 and constitutes a part of the hydraulic circuit 4.

Further, the rotor 17 has a concave second fitting hole 21 as a second insertion hole formed in the center of the inner surface on the rear plate 15 side in the rotation axis direction.

The second fitting hole 21 is formed in a columnar shape so that the first shaft portion 5a of the outer camshaft 5 and the second shaft portion 6a of the inner camshaft 6 can be respectively inserted from the rotation axis direction.

The second fitting hole 21 is formed so that the inner diameter is slightly larger than the outer diameter of the first shaft portion 5a, and the outer peripheral surface of the first shaft portion 5a is fitted into the inner peripheral surface in a tight state from the rotation axis direction. It has become. Therefore, the first shaft portion 5 a is suppressed from generating radial play in the second fitting hole 21. The inner diameter of the second fitting hole 21 is set slightly smaller than the inner diameter of the first fitting hole 20.

In the outer cam shaft 5, the first shaft portion 5a is fitted in the second fitting hole 21, but the outer cam shaft 5 and the vane rotor 3 are rotatable relative to each other. That is, the outer peripheral surface of the first shaft portion 5a and the inner peripheral surface of the second fitting hole 21 can slide with a minute gap.

Also, the second fitting hole 21 is formed in the bottom surface 21a so that one end in the axial direction of the passage constituting hole 17a is opened, and is in communication with the passage constituting hole 17a. The end face of the inner camshaft 6 abuts against the bottom surface 21a of the second fitting hole 21 from the axial direction via a thin annular spacer 22 after assembly.

Further, the rotor 17 is coupled to the other end portion of the inner camshaft 6 from the direction of the rotation axis through the target member 35 of the rotation detection mechanism by the axial force of the cam bolt 10. Further, the spacer 22 is fixed in a clamped state by the axial force of the cam bolt 10 between the distal end surface of the second shaft portion 6 a of the inner cam shaft 6 and the bottom surface 21 a of the second fitting hole 21 of the rotor 17.

The rotational position detection mechanism includes a detector that detects a rotational position from a plurality of protruding targets, and a target member 35 that is disposed in proximity to the detector. As shown in FIGS. 1 to 3, the target member 35 is integrally formed of a ferrous metal material, and has a cylindrical base portion 35a and a plurality of (provided integrally from the outer periphery of the base portion 35a via flanges 35b). In the present embodiment, the target projections 35c are three).

In the base portion 35a, an insertion hole 35d of the cam bolt 10 is formed so as to penetrate in the inner axial direction, and the front end portion is pressed against the fitting groove 17b of the rotor 17 by the axial force of the cam bolt 10 through the through hole 14a. Each target protrusion 35c is formed in an elongated rectangular shape, and is arranged so that the tip end surface is close to the detection portion of the detector in the radial direction.

Then, the detector that detects the position of each target protrusion 35 c as the vane rotor 3 (inner cam shaft 6) rotates detects the rotational position of the inner cam shaft 6 via the vane rotor 3. This rotational position information is output to the control unit 41 described later.

As described above, the rotor 17 has the first shaft portion 5a of the outer camshaft 5 fitted in the second fitting hole 21, but is not coupled to the outer camshaft 5 and can be freely relative to each other. Rotation is secured.

The first to fifth vanes 18a to 18e provided integrally on the outer peripheral surface of the rotor 17 are disposed between the shoes 13a to 13e of the housing body 13. As a result, the first hydraulic fluid chamber 23 and the second hydraulic fluid chamber 24, which are five working chambers, are formed between the first to fifth vanes 18a to 18e and the first to fifth shoes 13a to 13e, respectively. ing.

One of the first vanes 18a is formed so that the circumferential width and thickness are larger than those of the other second vanes 18b to 18e. However, the other second to fifth vanes 18b to 18e are set to have substantially the same width and thickness in the circumferential direction.

In addition, as shown in FIGS. 2, 5, and 6, the rotor 17 has an oil chamber 21 b formed on the bottom surface 21 a side of the second fitting hole 21. Five first oil holes 25 that are communicating oil passages are formed penetrating along the radial direction. Furthermore, five second oil holes 26, which are oil passages that communicate the passage-constituting holes 17 a in the rotor 17 and the respective second hydraulic oil chambers 24, are formed along the radial direction.

Sealing members 27 that slide in contact with the inner peripheral surface of the housing body 13 and seal the first and second hydraulic oil chambers 23 and 24 are fitted in the fitting grooves formed at the tip portions of the vanes 18a to 18e, respectively. It is fixed.

Further, as described above, when the vane rotor 3 rotates relative to the clockwise direction or the counterclockwise direction, the first vane 18a comes into contact with the first convex surface 13f or the second convex surface 13g. That is, in the drawing of the first vane 18a, one side surface in the clockwise direction (the second hydraulic oil chamber 24 side) abuts on the second convex surface 13g, and the counterclockwise side (the first hydraulic oil chamber 23 in the first vane 18a). The other side surface is in contact with the first convex surface 13f, and the maximum relative rotation of each is regulated.

FIG. 7 is a cross-sectional view taken along the line BB in FIG. 6 and clearly shows the lock mechanism 28.

2 and 7, the lock mechanism 28 is slidably accommodated in the sliding hole 29 formed in one vane 18a of the vane rotor 3, and is slidably accommodated in the sliding hole 29. The lock pin 30 is provided so as to be capable of moving forward and backward, the lock hole component 31 is fixed to the fixing hole 15c formed in the rear plate 15, and the lock pin 30 is formed in the lock hole component 31. A lock hole 31a for locking the vane rotor 3 by engaging the front end of the shaft, and an engagement / disengagement mechanism for engaging or disengaging the front end of the lock pin 30 with the lock hole 31a according to the engine operating state. It is configured.

The sliding hole 29 is formed in a substantially uniform diameter with a relatively large inner diameter, and is formed to penetrate in the axial direction.

The rear end portion of the lock pin 30 is formed to have a substantially uniform outer diameter corresponding to the sliding hole 29, and the front end portion 30a is formed to have a stepped small diameter slightly smaller than the inner diameter of the lock hole 31a. Further, the lock pin 30 is formed with two step-shaped first and second pressure receiving surfaces 30b and 30c between the rear end portion and the front end portion 30a. Further, two annular first and second pressure receiving chambers 34a and 34b are formed between the oil groove formed in the tip hole edge of the sliding hole 29 and the first and second pressure receiving surfaces 30b and 30c. Yes.

The lock holes 31a are formed in a bottomed cylindrical shape and are formed at predetermined intervals in the circumferential direction of the inner peripheral surface of the rear plate 15, and when the vane rotor 3 rotates relative to the maximum left direction shown in FIG. The lock pin 30 is formed at a position where the lock pin 30 is engaged from the axial direction.

The engagement / disengagement mechanism of the lock mechanism 28 supplies hydraulic pressure to the coil spring 32 that urges the lock pin 30 in the advancing direction (direction of the lock hole 31a), the first and second pressure receiving chambers 34a and 34b, and the lock hole 31a. The lock pin 30 is made up of two first and second release oil passages 33a and 33b for releasing the lock by retracting the lock pin 30 from the lock hole 31a.

As shown in FIG. 5, the first release oil passage 33 a is formed inside the rotor 17, and is branched from one first oil hole 25, so that one first hydraulic oil chamber 23 and the first release oil passage 23 are formed. One pressure receiving chamber 34a is communicated. As shown in FIG. 6, the other second release oil passage 33b is formed on the inner side of the first vane 18a, and communicates one second hydraulic oil chamber 24 and the second pressure receiving chamber 34b. .

Note that the sliding hole 29 communicates with the outside through a rectangular breathing groove 29 a formed on the outer surface of the rotor 17 on the first vane 18 a side and the through hole 14 a of the front plate 14. Thereby, the stable slidability of the lock pin 30 is ensured at all times.

The hydraulic circuit 4 selectively supplies or discharges hydraulic pressure to each first hydraulic fluid chamber 23 and each second hydraulic fluid chamber 24. Specifically, as shown in FIG. 2, a first oil passage 36 communicating with each first hydraulic oil chamber 23, a second oil passage 37 communicating with each second hydraulic oil chamber 24, and each oil passage An oil pump 39 that selectively supplies hydraulic pressure to the fluid passages 36 and 37 via the electromagnetic switching valve 38; and a drain passage 40 that selectively communicates with the oil passages 36 and 37 via the electromagnetic switching valve 38. Yes.

The first oil passage 36 is mainly formed between the inner peripheral surface of the outer cam shaft 5 and the outer peripheral surface of the inner cam shaft 6. One end of the first oil passage 36 is connected to the supply / discharge port of the electromagnetic switching valve 38, and the other end communicates with each first hydraulic oil chamber 23 via the oil chamber 21 b and each first oil hole 25. ing.

The second oil passage 37 is mainly formed between the outer peripheral surface of the cam bolt 10 and the inner peripheral surface of the inner camshaft 6. The second oil passage 37 has one end connected to the supply / discharge port of the electromagnetic switching valve 38 and the other end connected to each second hydraulic oil chamber 24 via the passage constituting hole 17a and each second oil hole 26. Communicating with

The electromagnetic switching valve 38 is a four-port two-position valve, and is an unillustrated spool provided inside by a change in the amount of control current (pulse current) applied from the control unit (ECU) 41 to an unillustrated electromagnetic coil. The valve moves in the axial direction. Thus, the discharge passage 39a of the oil pump 39 and the drain passage 40 are selectively switched and controlled for the oil passages 36 and 37, respectively. That is, when energized from the control unit 41, the discharge passage 39a and the first oil passage 36 are communicated, and at the same time, the drain passage 40 and the second oil passage 37 are communicated. On the other hand, when the energization is interrupted, the discharge passage 39a and the second oil passage 37 are communicated, and at the same time, the drain passage 40 and the first oil passage 36 are communicated.

The spool valve moves forward and backward in accordance with the amount of current supplied from the control unit 41, so that the opening area of the supply / discharge port communicating with each of the oil passages 36 and 37 is continuously variable.

In the control unit 41, an internal computer inputs information signals from various sensors such as a crank angle sensor, an air flow meter, a water temperature sensor, a throttle valve opening sensor, etc. (not shown) to detect the current engine operating state. Yes. A control current (pulse current) is output to the electromagnetic coil of the electromagnetic switching valve 38 based on the engine operating state and the rotational position information of the inner camshaft 6 detected by the rotational position detection mechanism.
[Operation of this embodiment]
FIG. 8 shows the first and second drive cams 7 and 11 used in this embodiment, A shows the state where both drive cams 7 and 11 are in the same rotational phase, and B shows the first drive cam 7. A state in which the second drive cam 11 changes the rotation phase is shown.

FIG. 9 shows a lift characteristic diagram of the intake valve in the present embodiment, A is a lift characteristic diagram in the case of relative rotation in the maximum one direction shown in FIG. 6, and B is a case of relative rotation in the maximum other direction shown in FIG. It is a lift characteristic figure.

For example, when the engine is started, the tip 30a of the lock pin 30 is engaged with the lock hole 31a in advance by the spring force of the coil spring 32 of the lock mechanism 28. For this reason, the vane rotor 3 is locked in a relative rotational position on the advance side, which is optimal for starting, for example, relative to the housing 2.

Thus, the two drive cams 7 and 11 are in the same rotational phase via the outer cam shaft 5 and the inner cam shaft 6 as shown in FIG. Therefore, the opening / closing timing characteristic of one intake valve is maintained at the initial retarded phase as shown in FIG. 9A.

Therefore, when the engine is started by turning on the ignition switch from this state, a good startability can be obtained by smooth cranking.

Thereafter, when the engine operating state shifts to a predetermined operating range, a control current is output from the control unit 41 to the electromagnetic switching valve 38, and first, the discharge passage 39a and the first oil passage 36 are communicated. Therefore, the hydraulic oil discharged from the oil pump 39 is supplied from the first oil passage 36 to the first hydraulic oil chambers 23 through the oil chambers 21 b and the first oil holes 25. Thereby, the hydraulic pressure in each hydraulic oil chamber 23 increases.

At the same time, the second oil passage 37 and the drain passage 40 are connected. For this reason, the hydraulic pressure in each second hydraulic oil chamber 24 is discharged to the oil pan 42, and the inside becomes a low pressure.

When the hydraulic pressure in each first hydraulic oil chamber 23 rises, the first hydraulic oil chamber 23 is supplied to the first pressure receiving chamber 34a through the first release oil passage 33a. As a result, the lock pin 30 moves backward against the spring force of the coil spring 32 by the high hydraulic pressure acting on the first pressure receiving surface 30b. Therefore, the distal end portion 30a of the lock pin 30 comes out of the lock hole 31a and the lock of the vane rotor 3 with respect to the housing 2 is released. Therefore, the vane rotor 3 is allowed to rotate freely.

The vane rotor 3 rotates relative to the housing 2 in the clockwise direction from the position shown in FIG. 6 as the pressure of each first hydraulic oil chamber 23 increases. Due to this relative rotation, the other side surface of the first vane 18a comes into contact with the second convex surface 13g and the maximum clockwise rotation position is regulated (see FIG. 5). Accordingly, the inner cam shaft 6 rotates relative to the outer cam shaft 5 in the clockwise direction.

Therefore, as shown in FIG. 8B, the first drive cam 7 on the outer camshaft 5 side is held at the rotational position on the retard side. However, the second drive cam 11 on the inner camshaft 6 side rotates relative to the rotation position further on the retard side (clockwise) with respect to the rotation direction indicated by the arrow, and the second drive cam 11 performs the first drive. The cam 7 is opened to the retard side (open angle state).

Therefore, one intake valve has a characteristic that its opening / closing timing characteristic is further retarded as shown in FIG. 9B. As a result, the two drive cams 7 and 11 push the valve lifter for a longer time than the time when the valve lifter is pushed in the initial phase. That is, the time during which one intake valve is open (operating angle) becomes longer, and the amount of intake air into the combustion chamber increases continuously. Thereby, for example, it becomes possible to improve the output torque at the time of high engine rotation or sudden acceleration.

Further, when the engine operating state further changes, the spool valve further moves in accordance with a large energization amount from the control unit 41 to the electromagnetic switching valve 38. For this reason, the first oil passage 36 and the drain passage 40 are communicated, and the second oil passage 37 and the discharge passage 39a are communicated. As a result, each first hydraulic oil chamber 23 has a low pressure, while each second hydraulic oil chamber 24 has a high pressure.

Therefore, the vane rotor 3 rotates relative to the housing 2 counterclockwise from the rotational position of FIG. Similarly, the inner camshaft 6 is controlled to rotate relative to the outer camshaft 6 counterclockwise so that the operating angle of one intake valve is reduced. As a result, the amount of intake air is reduced, and for example, fuel efficiency can be improved in the low engine speed range.

The relative rotational displacement between the first drive cam 7 and the second drive cam 11, that is, the expansion / contraction displacement of the second drive cam 11 will be continuously performed by the control unit 41 and the electromagnetic switching valve 38. It has become.

In the present embodiment, when the components are assembled, as shown in FIG. 1, the inner camshaft 6 is rotated by the cam bolt 10 with the second shaft portion 6 a fitted in the second fitting hole 21. 17 is fastened and fixed from the direction of the rotation axis.

On the other hand, the outer camshaft 5 is fastened and fixed to the rear plate 15 (housing 2) by each fastening bolt 9 via the flange portion 8. In the outer camshaft 5, the first shaft portion 5 a is fitted into the first fitting hole 20 of the rear plate 15 and the second fitting hole 21 of the rotor 17 from the rotation axis direction.

That is, the outer camshaft 5 is tightly fitted to the rear plate 15 of the housing 2 via the first fitting hole 20 and is relatively rotatable to the second fitting hole 21 of the rotor 17 of the vane rotor 3. It fits tightly in the state.

In other words, in this embodiment, both the housing 2 and the vane rotor 3 are coaxial by a single outer camshaft 5.

Therefore, highly accurate coaxiality between the housing 2 and the vane rotor 3 can be obtained. For this reason, even if backlash occurs between both axial centers of the outer cam shaft 5 and the inner cam shaft 6, the influence on the coaxiality of the housing 2 and the vane rotor 3 can be sufficiently suppressed.

Since the outer camshaft 5 is coupled to the rear plate 15 (housing 2) via the flange portion 8, the outer camshaft 5 can be integrated with the housing 2. Thereby, the influence on the coaxiality between the housing 2 and the vane rotor 3 is further reduced.

Further, in this embodiment, since the coaxiality of the housing 2 and the vane rotor 3 can be ensured with a simple structure using the outer camshaft 5, the manufacturing operation is facilitated and the cost can be reduced.

Furthermore, since the oil chamber 21b is configured as an oil path in the second fitting hole 21, it is not necessary to form an oil path separately. Therefore, also in this respect, the manufacturing operation is facilitated, and the cost can be reduced. Further, by using the second fitting hole 21 as a part of the oil passage, the apparatus can be reduced in size.

Further, a change in the relative rotational position of the second drive cam 11 with respect to the first drive cam 7, that is, a change in the expansion and contraction of the second drive cam 11 shown in FIGS. 8A and 8B is continuously performed. ing.

For this reason, the change of the open period of one intake valve shown to FIG. 9A and B is also controlled continuously. Since the operating angle (opening period) of one intake valve can be freely changed in accordance with changes in the engine operating state, engine performance such as fuel efficiency and output can be improved.
[Second Embodiment]
FIG. 10 shows the second embodiment, and the basic configuration is the same as that of the first embodiment, except that the tip portion 5b of the first shaft portion 5a of the outer camshaft 5 is formed in a stepped small diameter shape. ing. On the other hand, the rotor 17 is formed so that the inner diameter of the second fitting hole 21 is small in accordance with the outer diameter of the tip portion 5b of the first shaft portion 5a.

Other configurations such as the housing 2, the vane rotor 3, the rear plate 15, the inner camshaft 6 being inserted into the second fitting hole 21 and coupled to the rotor 17 by the cam bolt 10 are the same as in the first embodiment. It is.

And at the time of assembling each component, the outer camshaft 5 is inserted into the first fitting hole 20 of the rear plate 15 from the rotation axis direction on the base side of the first shaft portion 5a. As a result, the outer peripheral surface of the base portion of the first shaft portion 5 a is closely fitted to the inner peripheral surface of the first fitting hole 20. Further, the front end portion 5b of the first shaft portion 5a is fitted into the second fitting hole 21 from the rotation axis direction, and the outer peripheral surface of the front end portion 65b is tightly fitted to the inner peripheral surface of the second fitting hole 21. is doing.

Therefore, the coaxiality between the housing 2 and the vane rotor 3 can be ensured only by the outer cam shaft 5. For this reason, even if backlash occurs between both axial centers of the outer cam shaft 5 and the inner cam shaft 6, the influence on the coaxiality of the housing 2 and the vane rotor 3 can be sufficiently suppressed.

Moreover, in this embodiment, the internal diameter of the 2nd fitting hole 21 of the vane rotor 3 can also be formed small with the diameter reduction of the front-end | tip part 5b of the outer cam shaft 5. FIG. Accordingly, since the outer diameter of the rotor 17 of the vane rotor 3 can be reduced, the size of the entire apparatus in the radial direction can be reduced, and as a result, the apparatus can be made compact. Other than that, the same operational effects as the first embodiment can be obtained.
[Third Embodiment]
FIG. 11 shows the third embodiment, and the basic configuration is the same as that of the first embodiment, except that the inner surface of the first fitting hole 20 of the rear plate 15 is a part of the inner surface of the vane rotor 3 side. An annular third fitting hole 43 is formed. On the other hand, the rotor 17 is integrally provided with an annular cylindrical portion 44 fitted into the third fitting hole 43 from the axial direction on the outer peripheral surface of the end portion on the rear plate 15 side in the rotation axis direction.

The cylindrical portion 44 and the third fitting hole 43 are tightly fitted in a relatively rotatable state.

Further, the first shaft portion 5a of the outer camshaft 5 is closely fitted in the second fitting hole 21 from the rotation axis direction as in the first embodiment. However, the first shaft portion 5a is fitted in the second fitting hole 21 in a relatively rotatable state.

Note that the first fitting hole 20 of the rear plate 15 and the first shaft portion 5a of the outer camshaft 5 inserted into the first fitting hole 20 do not necessarily need to be tightly fitted. It may be fitted with a small gap.

Therefore, according to this embodiment, the first shaft portion 5a of the outer camshaft 5 is tightly fitted into the second fitting hole 21 of the rotor 17 from the direction of the rotation axis when assembled to each component. At the same time, the cylindrical portion 44 is tightly fitted into the third fitting hole 43 from the direction of the rotation axis.

For this reason, the outer camshaft 5 and the vane rotor 3 are arranged coaxially, and the vane rotor 3 and the rear plate 15 are also arranged coaxially.

Therefore, the coaxiality of the housing 2 and the vane rotor 3 can be obtained via the vane rotor 3 and the outer camshaft 5.

For this reason, even if backlash occurs between the shaft centers of the outer cam shaft 5 and the inner cam shaft 6, the influence on the coaxiality of the housing 2 and the vane rotor 3 can be sufficiently suppressed.

Other than that, the same effects as the first embodiment can be obtained.
[Fourth Embodiment]
FIG. 12 shows a fourth embodiment, in which the inner camshaft 6 ensures the coaxiality of the housing 2 and the vane rotor 3.

That is, the outer camshaft 5 is formed such that the axial length of the first shaft portion 5a is shorter than that of the other embodiments, and the second shaft portion 6a of the inner camshaft 6 is the first shaft portion 5a. It is greatly exposed from the front end opening toward the front plate 14.

The second shaft portion 6a is formed to have an outer diameter slightly larger than that of the other embodiments, the base portion 6b is inserted and fitted into the first fitting hole 20 of the rear plate 15, and the distal end portion 6c. Is fitted in the second fitting hole 21.

The outer diameter of the second shaft portion 6a from the base portion 6b to the tip portion 6c is set to be substantially uniform.

The first fitting hole 20 has an inner diameter smaller than that of the other embodiments, and is tightly inserted and fitted so that the base portion 6b of the second shaft portion 6a is relatively rotatable.

The second fitting hole 21 is formed so that its inner diameter is smaller than that of the other embodiments, and the tip portion 6c of the second shaft portion 6a is closely fitted in a state close to press-fitting.

In addition, an escape groove 15 a is formed in an annular shape that absorbs the tip of the first shaft portion 5 a of the outer camshaft 5 at the hole edge of the outer opening of the first fitting hole 20 of the rear plate 15.

Therefore, in this embodiment, when assembling each component, the base 6b side of the second shaft portion 6a of the inner camshaft 6 is inserted and fitted into the first fitting hole 20, and the tip portion 6c side is the second fitting. It is fitted in the joint hole 21. For this reason, the coaxiality of the housing 2 and the vane rotor 3 can be ensured only by the inner cam shaft 6.

For this reason, even if backlash occurs between the shaft centers of the outer cam shaft 5 and the inner cam shaft 6, the influence on the coaxiality of the housing 2 and the vane rotor 3 can be sufficiently suppressed.

In this embodiment, the inner diameter of each of the first fitting hole 20 and the second fitting hole 21 can be reduced according to the outer diameter of the second shaft portion 6a of the inner camshaft 6. For this reason, the outer diameters of the housing 2 and the vane rotor 3 can be reduced.

As a result, it becomes possible to reduce the outer diameter of the entire apparatus, and the degree of freedom of layout and mountability in the engine room are improved.

The present invention is not limited to the configuration of each embodiment. In each of the above embodiments, two drive cams 7 and 11 are used for one intake valve, but two exhaust valves per cylinder are used. In addition, the first driving cam 7 and the second driving cam 11 can be separately opened and closed and controlled to an open angle state.

Furthermore, in the present invention, the second rotating body is not limited to the vane rotor, and it is also possible to use, for example, a plurality of gear gears instead of the vane rotor.

Furthermore, it is also possible to perform unlocking of the locking mechanism by an electric means other than hydraulic such as an electric motor.

Further, in each embodiment, the hydraulic actuator has been described as the variable valve operating device. However, the hydraulic actuator can be used for a valve timing control device (VTC) as in the prior art, and also for other driving devices. is there.

Furthermore, the configuration of the rotational position detection mechanism is not limited to that of each embodiment, and for example, the structure of the target member 35 can be further changed.

As the variable valve operating apparatus based on the embodiment described above, for example, the following modes can be considered.

In one aspect thereof, an internal combustion engine comprising an inner hollow outer camshaft having an outer cam on the outer periphery, and an inner camshaft disposed in the outer camshaft so as to be relatively rotatable and having an inner cam on the outer periphery. In the variable valve gear of
A first rotating body having a first fitting hole into which a first shaft portion extending from one of the outer cam shaft and the inner cam shaft is fitted, and fixed to the outer cam shaft;
A second rotating body that is disposed inside the first rotating body, has a second fitting hole into which the first shaft portion is fitted, and is fixed to the inner camshaft.

According to this, both the first rotating body and the second rotating body can be coaxial with each other on the inner cam shaft or the outer cam shaft.

More preferably, the first shaft portion extends from one end portion of the outer cam shaft in the rotation axis direction, and the space between the outer peripheral surface of the first shaft and the inner peripheral surface of the second fitting hole is: Relative rotation is possible.

Therefore, the outer camshaft can be coaxial with the inner camshaft.

More preferably, the second rotating body is fixed to a second shaft portion that extends from one end portion of the inner cam shaft in the rotation axis direction and is inserted into the second fitting hole, and the first shaft portion and the second shaft portion. A radial gap centered on the rotation axis of the second shaft portion between the fitting hole and the rotation shaft of the second shaft portion between the second shaft portion and the second fitting hole is centered. It is formed smaller than the radial gap.

More preferably, an end portion of a first oil passage communicating with the first working chamber or the second working chamber divided into a plurality of working chambers provided in the first rotating body is opened in the second fitting hole. Is formed.

Therefore, since the second fitting hole can be used as an oil passage, the apparatus can be made compact.

More preferably, a second oil passage communicating with the first working chamber or the second working chamber is formed between the outer cam shaft and the inner cam shaft.

More preferably, the first oil passage or the second oil passage is formed on the inner periphery of the inner camshaft.

More preferably, a flange portion fixed to the first rotating body is fixed to the outer camshaft.

Therefore, since the outer camshaft is fixed to the first rotating body using the flange portion, the coaxiality is less affected.

More preferably, the outer cam shaft has the first shaft portion at the end in the rotation axis direction, and the outer diameter of the first shaft portion is formed to be smaller in step than the outer diameter of the outer cam shaft main body. And
The first shaft portion having a small diameter was fitted in the second fitting hole of the vane rotor from the axial direction.

Therefore, since the inner diameter of the second fitting hole can be reduced, it is possible to increase the space for forming the working chamber.

More preferably, in the first rotating body, a third fitting hole having a small step is formed on the inner periphery of the first fitting hole, while the second rotating body is formed of the second fitting hole. A cylindrical portion that is fitted into the third fitting hole from the axial direction is provided at the axial end portion on the side.

More preferably, at the end of the inner cam shaft on the second fitting hole side in the rotation axis direction, the first fitting hole of the first rotating body and the second fitting hole of the second rotating body, respectively. A second shaft portion to be inserted and fitted is provided.

In another preferred embodiment, the variable valve for an internal combustion engine changes the operating characteristics of the engine valve by relatively rotating an inner hollow outer camshaft and an inner camshaft inserted and arranged in the outer camshaft. A device having a working chamber therein, centered by one of the outer camshaft or the inner camshaft, and fixed to the outer camshaft; and disposed inside the housing; A vane rotor that has a vane that divides the working chamber into a plurality of parts, is centered by any one of the outer camshaft and the inner camshaft, and is centered by the camshaft that centers the housing, and is fixed to the inner camshaft; It has.

Therefore, since either the outer cam shaft or the inner cam shaft is coaxial with both the first rotating body and the second rotating body, the influence of backlash between the two cam shafts is suppressed.

More preferably, the housing has a first insertion hole into which the outer cam shaft is inserted, and the vane rotor has a second insertion hole into which the outer cam shaft is inserted. The first clearance in the rotational axis radial direction of the outer cam shaft between the inner peripheral surface and the outer peripheral surface of the outer cam shaft is between the inner peripheral surface of the second insertion hole and the outer peripheral surface of the inner cam shaft. It is formed smaller than the second clearance in the radial direction.

More preferably, the vane rotor has a communication hole formed therein for communicating the second insertion hole and the working chamber.

More preferably, the second insertion hole has an oil passage communicating with the communication hole therein.

More preferably, the inner camshaft is tightly inserted into the first insertion hole of the housing and is closely inserted into the second insertion hole of the vane rotor to obtain a coaxial relationship between the housing and the vane rotor. It is like that.

Claims (15)

In a variable valve operating apparatus for an internal combustion engine, comprising: a hollow outer camshaft having an outer cam on the outer periphery; and an inner camshaft disposed in the outer camshaft so as to be relatively rotatable and having an inner cam on the outer periphery.
A first rotating body having a first fitting hole into which a first shaft portion extending from one of the outer cam shaft and the inner cam shaft is fitted, and fixed to the outer cam shaft;
A second rotating body disposed within the first rotating body, having a second fitting hole into which the first shaft portion is fitted, and fixed to the inner camshaft;
A variable valve operating apparatus for an internal combustion engine, comprising: A variable valve operating apparatus for an internal combustion engine according to claim 1,
The first shaft portion extends from one end portion of the outer cam shaft in the rotation axis direction,
A variable valve operating apparatus for an internal combustion engine, characterized in that relative rotation is possible between an outer peripheral surface of the first shaft and an inner peripheral surface of the second fitting hole. A variable valve operating apparatus for an internal combustion engine according to claim 2,
The second rotating body is fixed to a second shaft portion extending from one end portion of the inner cam shaft in the rotation axis direction and inserted through the second fitting hole,
The radial gap between the first shaft portion and the second fitting hole, with the rotation axis of the second shaft portion as the center, is the first gap between the second shaft portion and the second fitting hole. 2. A variable valve operating apparatus for an internal combustion engine, wherein the variable valve operating apparatus is formed to be smaller than a radial gap centered on a rotation axis of two shaft portions. A variable valve operating apparatus for an internal combustion engine according to claim 2,
In the second fitting hole, an end portion of a first oil passage communicating with the first working chamber or the second working chamber divided into a plurality of working chambers in the first rotating body is formed. A variable valve operating apparatus for an internal combustion engine. A variable valve operating apparatus for an internal combustion engine according to claim 4,
A variable valve operating apparatus for an internal combustion engine, wherein a second oil passage communicating with the first working chamber or the second working chamber is formed between the outer cam shaft and the inner cam shaft. A variable valve operating apparatus for an internal combustion engine according to claim 5,
The variable valve operating apparatus for an internal combustion engine, wherein the first oil passage or the second oil passage is formed on an inner periphery of the inner camshaft. A variable valve operating apparatus for an internal combustion engine according to claim 4,
A variable valve operating apparatus for an internal combustion engine, wherein a flange portion fixed to the first rotating body is fixed to the outer camshaft. A variable valve operating apparatus for an internal combustion engine according to claim 1,
The outer cam shaft has the first shaft portion at the end in the rotation axis direction, and the outer diameter of the first shaft portion is formed to be smaller in step than the outer diameter of the outer cam shaft main body,
The variable valve operating apparatus for an internal combustion engine, wherein the first shaft portion having a small diameter is fitted in the second fitting hole of the vane rotor from the axial direction. A variable valve operating apparatus for an internal combustion engine according to claim 1,
While the first rotating body has a third fitting hole having a small stepped diameter formed on the inner periphery of the first fitting hole,
The second rotating body may be provided with a cylindrical portion that is fitted in the third fitting hole from the axial direction at an axial end portion on the second fitting hole side. Variable valve device. A variable valve operating apparatus for an internal combustion engine according to claim 1,
The inner camshaft is inserted and fitted into the first fitting hole of the first rotating body and the second fitting hole of the second rotating body at the end of the inner camshaft in the direction of the second fitting hole. A variable valve operating apparatus for an internal combustion engine, characterized in that a second shaft portion is provided. A variable valve operating apparatus for an internal combustion engine that changes an operating characteristic of an engine valve by relatively rotating an inner hollow outer camshaft and an inner camshaft disposed inside the outer camshaft,
A cylindrical housing having an operating chamber inside, centered by one of the outer cam shaft or the inner cam shaft, and fixed to the outer cam shaft;
The inner cam has a vane that is disposed inside the housing and divides the working chamber into a plurality of parts, and is centered by one of the outer camshaft and the inner camshaft that centers the housing. A vane rotor fixed to the shaft;
A variable valve operating apparatus for an internal combustion engine comprising: A variable valve operating apparatus for an internal combustion engine according to claim 11,
The housing has a first insertion hole into which the outer camshaft is inserted,
The vane rotor has a second insertion hole into which the outer camshaft is inserted,
The first clearance in the rotational axis radial direction of the outer cam shaft between the inner peripheral surface of the second insertion hole and the outer peripheral surface of the outer cam shaft is the inner peripheral surface of the second insertion hole and the inner cam shaft. A variable valve operating apparatus for an internal combustion engine, wherein the variable valve operating apparatus is smaller than a radial second clearance between the outer peripheral surface of the internal combustion engine. The variable valve operating apparatus for an internal combustion engine according to claim 12,
The variable valve operating apparatus for an internal combustion engine, wherein the vane rotor has a communication hole formed therein for communicating the second insertion hole and the working chamber. A variable valve operating apparatus for an internal combustion engine according to claim 13,
The variable valve operating apparatus for an internal combustion engine, wherein the second insertion hole has an oil passage communicating with the communication hole. The variable valve operating apparatus for an internal combustion engine according to claim 12,
The inner camshaft is inserted tightly into the first insertion hole of the housing and closely inserted into the second insertion hole of the vane rotor to obtain the coaxial of the housing and the vane rotor. A variable valve operating device for an internal combustion engine.

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