JP2011144780A - Variable valve system of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable valve system of internal combustion engine capable of switching, at individually different timing a plurality of cams at low cost attributable to a common displacement means, with respect to the variable valve control system of internal combustion engine. <P>SOLUTION: A cam shaft 12 is provided with a plurality of cams including first cams 14, 18, 22, 26 and second cams 16, 20, 24, 28 which are arranged adjacently to each other and are different in profile. There are provided transmission members 30, 34 which contact selectively with any one of the first and second cams and thereby transmits, to a valve 36, the operational force output from the first cams or the second cams. A displacement means 42 is included which displaces relatively the cam shaft and the transmission member in the axial direction of the cam shaft. There are differences in width between a plurality of the first cams and a plurality of the second cams. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a variable valve operating apparatus for an internal combustion engine.

  Conventionally, for example, in Patent Document 1, a cam carrier provided with a cam having a first cam portion and a second cam portion having different profiles is provided for each cylinder, and each cam carrier is attached to a cam shaft that is rotationally driven. A valve operating mechanism for an internal combustion engine that switches a cam by moving in an axial direction is disclosed. More specifically, in this conventional valve mechanism, each cam carrier is provided with a displacement means such as an electric actuator, and the cam carrier is individually displaced by operating the displacement means at an individual timing. Thereby, the lift amount of the valve can be changed by switching a plurality of cams at individual timings.

JP 2006-520869 A JP-A-3-23608 JP 2002-138808 A

  However, the conventional valve mechanism requires a displacement means such as an electric actuator for each cam carrier in order to switch a plurality of cams at individual timings. If a displacement means is required for each cam carrier, an EDU for driving an electric actuator or the like is also required in order to secure the number of actuators, the number of connectors and the number of microcomputer ports corresponding thereto, and the restriction of the heat generation amount. Therefore, there is a problem that the cost of the system increases.

  The present invention has been made to solve the above-described problems, and provides a variable valve operating apparatus for an internal combustion engine capable of switching a plurality of cams at individual timings at a low cost by a common displacement means. With the goal.

In order to achieve the above object, a first invention is a variable valve operating apparatus for an internal combustion engine,
A rotationally driven camshaft;
A plurality of cams provided on the camshaft, each having a first cam portion and a second cam portion having different profiles arranged adjacent to each other;
A transmission member that selectively contacts one of the first cam portion and the second cam portion, and transmits the acting force from the first cam portion or the second cam portion to the valve;
Displacement means for relatively displacing the camshaft and the transmission member in the axial direction of the camshaft;
The width of the second cam portion with respect to the width of the first cam portion is different in the plurality of cams.

The second invention is the first invention, wherein
The width of the first cam portion is set to be wider for cams with a slower switching order.

The third invention is the second invention, wherein
The switching order is the same order as the explosion order.

According to a fourth invention, in any one of the first to third inventions,
One of the first cam part and the second cam part is a resting cam part comprising an arcuate base circle part coaxial with the camshaft.

According to a fifth invention, in any one of the first to fourth inventions,
The displacement means is
Displace the camshaft to a displacement end position where the cam portion that contacts the transmission member of the plurality of cams switches from the first cam portion to the second cam portion,
A spiral groove formed on an outer peripheral surface of a rotating body that rotates together with the camshaft, and guides the camshaft in its axial direction;
A switching pin that can be inserted into and removed from the spiral groove;
An actuator for inserting the switching pin into the spiral groove,
The spiral groove is
While the camshaft is rotated longer than one rotation, the camshaft is guided from the position where the switching pin is inserted into the spiral groove to the displacement end position.

  According to the first invention, the camshaft and the transmission member are relatively displaced in the axial direction of the camshaft by the displacement means. The camshaft is provided with a plurality of cams having a first cam portion and a second cam portion having different adjacent profiles. Either the first cam portion or the second cam portion selectively contacts the transmission member. Therefore, by relatively displacing the camshaft and the transmission member in the axial direction of the camshaft as described above, the cam portions contacting the transmission member can be simultaneously slid by the same distance in the plurality of cams. According to the first aspect, the width of the second cam portion relative to the width of the first cam portion is different in the plurality of cams. Therefore, a plurality of cams can be switched at different timings. Thus, according to the present invention, the plurality of cams can be sequentially switched by the common displacement means, and the cost of the system can be suppressed.

  According to the second aspect of the invention, the width of the first cam portion is set wider as the cam whose switching order is slower. For this reason, according to this invention, a cam can be switched sequentially according to switching order.

  According to the third invention, the switching order is the same as the explosion order. For this reason, according to this invention, a cam can be switched sequentially according to an explosion order.

  According to the fourth aspect of the invention, either the first cam portion or the second cam portion is a pause cam portion that is formed of an arc-shaped base circle portion that is coaxial with the camshaft. For this reason, according to the present invention, each cylinder can be stopped by stopping the valve.

  According to the fifth aspect, the spiral groove guides the camshaft from the position where the switching pin is inserted into the spiral groove to the displacement end position while the camshaft is rotated longer than one rotation. Therefore, compared with the spiral groove that guides the camshaft to the displacement end position during one rotation of the camshaft, the inclination of the spiral groove in the circumferential direction can be made gentle. For this reason, according to this invention, durability of a helical groove | channel can be improved.

1 is a diagram schematically showing an overall configuration of a variable valve operating apparatus for an internal combustion engine according to a first embodiment of the present invention. FIG. 2 is a view of a two-valve drive rocker arm 30 of a cylinder # 1 as viewed from the axial direction of a camshaft 12. It is a figure which shows schematically the whole structure of the variable valve apparatus of the internal combustion engine of Embodiment 2 of this invention. It is a figure which shows the relationship between a valve lift timing and the sliding amount to the axial direction of the cam by the helical groove | channel 56 for a pause. It is a figure which shows the displacement process of the camshaft 12 until the switching of a cam is completed in all the cylinders. In Embodiment 3 of this invention, it is a figure which shows the 1st example which switches the cam of 4 cylinders by camshaft 2 rotation. In Embodiment 3 of this invention, it is a figure which shows the 2nd example which switches the cam of 4 cylinders by camshaft 2 rotation. In Embodiment 3 of this invention, it is a figure which shows the example which switches the cam of 4 cylinders by camshaft 3 rotation.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted.

Embodiment 1 FIG.
[Overall configuration of variable valve system]
The system configuration will be described with reference to FIGS. FIG. 1 is a diagram schematically showing an overall configuration of a variable valve operating apparatus for an internal combustion engine according to a first embodiment of the present invention. Here, the internal combustion engine 1 has four cylinders (# 1 to # 4) and is an in-line four-cylinder engine in which an explosion stroke is performed in the order of # 1 → # 3 → # 4 → # 2. To do. In addition, each cylinder of the internal combustion engine 1 is provided with two intake valves and two exhaust valves. The configuration shown in FIG. 1 functions as a mechanism for driving two intake valves or two exhaust valves disposed in each cylinder.

  The variable valve operating apparatus 10 of this embodiment includes a camshaft 12 that is common to the cylinders # 1 to # 4. The camshaft 12 is supported by a cam carrier (or a cylinder head or the like) that is a stationary member of the internal combustion engine 1 so as to be rotatable in the circumferential direction and displaceable in the axial direction. The camshaft 12 is connected to a crankshaft (not shown) by a timing chain or a timing belt, and is configured to rotate at a half speed of the crankshaft. The camshaft 12 is provided with a main cam and a sub cam adjacent to each cylinder as a pair of cams. Specifically, the camshaft 12 has a main cam 14 and a sub cam 16 for cylinder # 1, a main cam 18 and a sub cam 20 for cylinder # 2, and a main cam 18 for cylinder # 3. The cam 22 and the sub cam 24 are formed integrally with the camshaft 12 as a pair of cams, with the main cam 26 and the sub cam 28 being adjacent to the cylinder # 4.

  FIG. 2 is a view of the two-valve drive rocker arm 30 of the cylinder # 1 as viewed from the axial direction of the camshaft 12. As shown in FIG. 2, the main cam 14 has an arcuate base circle portion 14a coaxial with the camshaft 12, and a nose portion 14b formed so as to bulge a part of the base circle toward the radially outer side. It is a normal cam equipped with. Further, in the present embodiment, the sub cam 16 is configured as a pause cam having only a circular arc base circle coaxial with the cam shaft 12. The main cams 18, 22, and 26 are also normal cams having a base circle portion and a nose portion, like the main cam 14. The sub cams 20, 24, and 28 are also rest cams having only a base circle portion, similar to the sub cam 16.

  As shown in FIG. 2, the variable valve gear 10 includes a rocker shaft 32 arranged in parallel with the camshaft 12. A two-valve drive rocker arm 30 for each cylinder is rotatably attached to the rocker shaft 32. A roller 34 is rotatably attached to a central portion of the two-valve drive rocker arm 30 at a position where it can contact the main cam 14. Further, the base end portions of the two valves 36 (specifically, the base end portions of the valve stems) are in contact with the opposite end of the rocker shaft 32 in the two-valve drive rocker arm 30.

  The rocker shaft 32 is assumed to be supported by a cam carrier (or a cylinder head or the like) that is a stationary member of the internal combustion engine 1 via a lash adjuster 38. Therefore, the two-valve drive rocker arm 30 is biased toward the main cam 14 by receiving a pushing force from the lash adjuster 38. Further, the two-valve drive rocker arm 30 is pressed against the main cam by the urging force of the valve spring 40 when the main cam 14 lifts the valve 36. The two-valve drive rocker arm 30 configured as described above swings about the rocker shaft 32 as a fulcrum by the cooperation of the acting force of the main cam 14 and the urging force of the lash adjuster 38 and the valve spring 40. The valve 36 is opened and closed by swinging the two-valve drive rocker arm 30.

  The cylinders # 2 to # 4 also have the same configuration as in FIG. 2 except that the main cam 14 is replaced with the main cams 18, 22, and 26, and the sub cam 16 is replaced with the sub cams 20, 24, and 28, respectively. (Fig. 1). Since it is the same structure, the description is abbreviate | omitted.

[Characteristic configuration of this embodiment]
Next, a first characteristic configuration in the present embodiment will be described. The first characteristic configuration in the present embodiment is that the cam widths of the main cams 14, 18, 22, and 26 provided on the camshaft 12 common to the cylinders # 1 to # 4 are designed at unequal intervals, and the actuator 42 Thus, the camshaft 12 is moved in the axial direction to sequentially switch the cams of the cylinders # 1 to # 4.

  As described above, the cylinders # 1 to # 4 undergo an explosion stroke in the order of # 1, # 3, # 4, and # 2. In this explosion sequence, the rotation angle of the camshaft 12 is delayed by 90 °. Specifically, the cylinder # 1 is provided with a nose portion facing downward in the drawing of FIG. Cylinder # 2 is provided with a nose portion vertically upward of the paper surface of FIG. Cylinder # 3 is provided with a nose portion vertically downward from the paper surface of FIG. Cylinder # 4 is provided with a nose portion facing upward in the drawing of FIG. The camshaft 12 rotates clockwise as viewed from the direction A in FIG.

  The cam widths of the main cam and the sub cam are different in each cylinder. The cam width of the main cam is configured to increase at equal intervals (10 mm intervals) in the order of the main cam 14 of cylinder # 1, the main cam 22 of cylinder # 3, the main cam 26 of cylinder # 4, and the main cam 18 of cylinder # 2. ing. Further, the cam width of the sub cam is smaller at equal intervals (10 mm intervals) in the order of the sub cam 16 of the cylinder # 1, the sub cam 24 of the cylinder # 3, the sub cam 28 of the cylinder # 4, and the sub cam 20 of the cylinder # 2. It is configured. Further, in each cylinder, the total cam width of the main cam and the sub cam, that is, the cam width of a pair of cams is the same. Therefore, in other words, the cam width of the sub cam with respect to the cam width of the main cam is different in the plurality of pairs of cams.

  As shown in FIG. 1, the variable valve operating apparatus 10 includes an actuator 42 that moves the camshaft 12 in the axial direction of the rotating shaft of the camshaft 12 (the axial direction of the camshaft 12). As the actuator 42, for example, an electric motor that directly drives the camshaft 12 or a hydraulic actuator that drives the camshaft 12 by hydraulic pressure is used. The actuator 42 is driven according to a drive signal from an ECU (Electronic Control Unit) 50. The ECU 50 is an electronic control unit for controlling the operating state of the internal combustion engine 1 based on output values of various sensors. As one of the controls, the ECU 50 determines a normal operation by the main cam (normal cam) or a valve stop operation by the sub cam (rest cam) based on the output values of various sensors. The actuator 42 is controlled at a timing based on the output signal. The crank position sensor is a sensor that detects the rotational speed of the crankshaft of the internal combustion engine 1.

  As shown in FIG. 1, the rollers 34 of the cylinders # 1 to # 4 are in a position where they are in sliding contact with the main cam in each cylinder, as shown in FIG. When the ECU 50 determines the above-described valve stop operation by the sub cam, the ECU 50 outputs a drive signal to the actuator 42 at the timing when the base circle of the # 1 main cam 14 is in sliding contact with the roller 34 based on the output signal of the crank position sensor. To do. The actuator 42 displaces the camshaft 12 in the direction A in FIG. 1 according to the drive signal. Due to the displacement of the camshaft 12, the main cam and the sub cam of the cylinders # 1 to # 4 are simultaneously displaced by the same distance.

  The actuator 42 is in sliding contact with the roller 34 of the cylinder # 1 when the base circle of the main cam 14 of the cylinder # 1 is in sliding contact with the roller 34, that is, when the valve 36 of the cylinder # 1 is closed. The camshaft 12 is displaced so that the cam is slid from the main cam 14 to the sub cam 16 for switching.

  Subsequently, even in cylinders # 3, # 4, and # 2 in which the rotation angle of the camshaft 12 is delayed by 90 °, the actuator 42 is in a state where the base circular portion of the main cam is in sliding contact with the roller 34, that is, each cylinder. When the valve 36 is closed, the camshaft 12 is displaced so that the cam slidingly contacting the roller 34 of each cylinder is switched from the main cam to the sub cam.

  As a result, the roller 34 of each cylinder slides on the cam from a position where it contacts the main cam in all cylinders to a position where it contacts the sub cam in all cylinders. The sliding distance is the same for each cylinder. Since the auxiliary cam is a rest cam with only the base circle, the state where the acting force of the auxiliary cam is transmitted to the valve 36 means a state where the valve 36 does not open and close (valve stopped state).

  According to the above configuration, the camshaft 12 is displaced by one actuator 42 in response to a valve stop request. Therefore, the number of actuators and the increase in EDU that controls the actuators can be suppressed, and the cost can be reduced. Further, according to the above-described configuration, the cams of all the cylinders are simultaneously slid by the same distance by the displacement of the camshaft 12, and the cam width of the main cam is reduced in order, that is, cylinders # 1 → # 3 → # 4 → # 2. Switch from the primary cam to the secondary cam in order. Therefore, the cams can be switched sequentially according to the explosion order. Furthermore, according to the above-described configuration, the cam is slid at the base circle portion in accordance with the rotation angle of the camshaft 12. Therefore, the valve can be stopped by switching the cam with a small thrust and a good response during the valve closing period of each cylinder.

  While it is very difficult to finish the cam in a three-dimensional shape, it is easy to finish the two-dimensional shape as a two-dimensional cam of a normal cam and a rest cam as described above. In addition, the three-dimensional cam requires a large thrust to slide the cam shaft 12 during the lift, whereas the two-dimensional cam has a flat axial direction and is easy to slide. Further, since the sliding surface of the two-dimensional cam is flat and not three-dimensional, a general general-purpose rocker arm can be used.

  By the way, in the system of the first embodiment described above, the auxiliary cams 16, 20, 24, and 28 are pause cams having only a base circle portion, but these auxiliary cams are cams having a lift amount other than 0 different from the main cam. It may be. This point is the same in the following embodiments.

  Further, in the system of the first embodiment described above, all four cylinders are deactivated, but at least two cylinders having different cam switching timings may be deactivated. This also applies to the following embodiments.

  Further, in the system of the first embodiment described above, the camshaft 12 is rotated in conjunction with the crankshaft by being connected to the timing chain or the timing belt, but the camshaft 12 is interlocked with the crankshaft. The means is not limited to this. For example, first, the camshaft 12 is hollow, and a shaft core member is inserted as the shaft core. The shaft core member supports the camshaft 12 so as to rotate in conjunction with the circumferential direction, and supports the camshaft 12 so as to be displaceable in the axial direction. The shaft core member may be connected to a timing chain or timing belt and rotated in conjunction with the crankshaft. This also applies to the following embodiments.

  Further, in the system of the first embodiment described above, the camshaft 12 is displaced in the axial direction to slide the cam that is in sliding contact with the roller 34 of each cylinder, but the object to be displaced is limited to this. is not. For example, the two-valve drive rocker arm 30 is fixed to the rocker shaft 32 in the axial direction, and the rocker shaft 32 is displaced in the axial direction so that the roller 34 of each cylinder slides with respect to the cam provided on the camshaft 12. It is good as well. This point is the same in the following embodiments.

  In the first embodiment described above, the camshaft 12 is the “camshaft” in the first invention, and the main cams 14, 18, 22, 26 are the “first cam portion” in the first invention. The auxiliary cams 16, 20, 24, 28 are the “second cam portion” in the first invention, the valve 36 is the “valve” in the first invention, and the rocker arm 30 and the roller 34 are the first invention. The actuator 42 corresponds to the “displacement means” in the first aspect of the invention.

Embodiment 2. FIG.
[System Configuration of Embodiment 2]
Next, a second embodiment of the present invention will be described with reference to FIGS. In the configuration shown in FIG. 3, the system of this embodiment can be realized by configuring the spiral grooves and the cam widths of the main cam and the sub cam as shown in FIGS.

[Characteristic configuration of this embodiment]
In Embodiment 1 mentioned above, a cam can be switched suitably by sliding a cam with a base circle part according to the rotation angle of the cam shaft 12. FIG. However, the rotational speed of the camshaft 12 differs depending on the operating state, and the operation timing and thrust required for the motor and the like differ. Therefore, it is not always easy to control the operation timing and thrust for sliding the cam. Therefore, it is more desirable if the cam can be reliably slid at the base circle without depending on the rotational speed of the camshaft 12 or the like.

  Therefore, in the present embodiment, a spiral groove that rotates together with the camshaft 12 as shown in FIG. 3 is used, and the camshaft 12 is displaced at a timing that is physically determined in the spiral groove so that a cam is formed at the base circle. It was decided to slide it securely.

  FIG. 3 is a diagram schematically showing an overall configuration of the variable valve operating apparatus for an internal combustion engine according to the second embodiment of the present invention. 3 that are the same as those in FIG. 1 are assigned the same reference numerals and descriptions thereof are omitted. Large-diameter portions 52 and 54 having outer diameters larger than those of the camshaft 12 are formed on the outer peripheral surfaces of both end portions of the camshaft 12 shown in FIG. A suspension spiral groove 56 extending in the circumferential direction is formed on the peripheral surface of the large diameter portion 52. A return spiral groove 58 extending in the circumferential direction is formed on the peripheral surface of the large diameter portion 54. The return spiral groove 58 is formed in a direction opposite to that of the resting spiral groove 56.

  The variable valve operating apparatus 10 includes a resting actuator 62 for inserting the switching pin 60 into the resting spiral groove 56. The variable valve operating apparatus 10 also includes a return actuator 66 for inserting the switching pin 64 into the return spiral groove 58. More specifically, the actuators 62 and 66 are solenoids that are duty-controlled based on commands from the ECU 50. The switching pins 60 and 64 are pushed out toward the spiral grooves 56 and 58 when the solenoid is ON, and are pulled out of the spiral grooves 56 and 58 when the solenoid is OFF. The width of the spiral grooves 56 and 58 is slightly larger than the outer shape of the switching pins 60 and 64.

  FIG. 4 is a diagram showing the relationship between the valve lift timing and the amount of sliding of the cam in the axial direction by the suspension spiral groove 56. FIG. 5 is a diagram showing a displacement process of the camshaft 12 until the cam switching is completed in all cylinders. As shown in FIG. 4, the valve lift timing of each cylinder is 90 degrees out of phase with the rotation angle of the camshaft 12, and the valves 36 of each cylinder # 1 → # 3 → # 4 with an overlap. → It is opened and closed in the order of # 2. The suspension spiral groove 56 rotates the camshaft 12 once to displace the camshaft 12 in the A direction by 40 mm. Therefore, the inclination of the resting spiral groove 56 with respect to the circumferential direction of the camshaft 12 is represented by 0.111 mm / ° obtained by dividing the displacement distance 40 mm of the camshaft 12 by the rotation angle 360 ° for one rotation of the camshaft. This is an inclination in which the camshaft 12 is displaced by 0.111 mm when the camshaft 12 rotates by 1 °.

  The rotation angle of the camshaft 12 at the time of maximum lift of the valve of the cylinder # 1 in FIG. 4 is 0 °. When a valve stop request is detected at a rotation angle of 0 ° of the camshaft 12, the ECU 50 turns on the pause actuator 62 (FIG. 5A). When the resting actuator 62 is turned on, the switching pin 60 is pushed out and inserted into the starting end of the resting spiral groove 56 (FIG. 5A). Thereafter, the switching pin 60 is fitted into the resting spiral groove 56 while the camshaft 12 rotates about 45 ° (FIG. 4).

  When the switching pin 60 is engaged, the resting spiral groove 56 receives the rotational force of the camshaft 12 and slides the camshaft 12 in the A direction (FIG. 6A). In the cylinder # 1, after the valve 36 is closed, the main cam 14 is slid by 10 mm in the axial direction of the camshaft 12 while the camshaft 12 rotates about 135 ° (FIG. 4). By sliding 10 mm, the cam slidingly contacting the roller 34 of cylinder # 1 is switched from the main cam 14 to the sub cam 16. The cam width of the main cam 14 is designed such that it slides 10 mm from the displacement start position where the roller 34 and the main cam 14 are in sliding contact during normal operation and switches to the sub cam 16.

  As shown in FIG. 5B, in a state where the camshaft 12 rotates about 135 °, the cylinder # 1 is deactivated. Also in the cylinders # 2 to # 4, the respective rollers 34 are slid by 10 mm on the main cams 18, 22, and 26.

  Further, when the camshaft 12 rotates about 135 °, the valve 36 of the cylinder # 3 is closed. Thereafter, while the camshaft 12 rotates to about 225 °, the main cam 22 of the cylinder # 3 is further slid by 10 mm in the axial direction of the camshaft 12 (FIG. 4). That is, it slides 20 mm from the displacement start position. By sliding 20 mm, the cam with which the roller 34 of the cylinder # 3 is in sliding contact is switched from the main cam 22 to the sub cam 24. The cam width of the main cam 22 is designed so that the cam that slides 20 mm from the displacement start position and is in sliding contact with the roller 34 of the cylinder # 3 is switched to the sub cam 24.

  As shown in FIG. 5C, the cylinders # 1 and # 3 are deactivated while the camshaft 12 is rotated by about 225 °. In the cylinders # 2 and # 4, the rollers 34 are slid 20 mm on the main cams 18 and 26, respectively.

  When the camshaft 12 rotates about 225 °, the valve 36 of the cylinder # 4 is closed. Thereafter, while the camshaft 12 rotates to about 315 °, the main cam 26 of the cylinder # 4 is further slid by 10 mm in the axial direction of the camshaft 12 (FIG. 4). That is, it slides 30 mm from the displacement start position. By sliding by 30 mm, the cam with which the roller 34 of the cylinder # 4 is in sliding contact is switched from the main cam 26 to the sub cam 28. The cam width of the main cam 26 is designed so that the cam that is slid 30 mm from the displacement start position and is in sliding contact with the roller 34 of the cylinder # 4 is switched to the sub cam 28.

  As shown in FIG. 5D, the cylinders # 1, # 3, and # 4 are deactivated while the camshaft 12 is rotated about 315 °. Also in the cylinder # 2, the roller 34 is slid by 30 mm on the main cam 18.

  Further, when the camshaft 12 rotates about 315 °, the valve 36 of the cylinder # 2 is closed. Thereafter, while the camshaft 12 rotates to about 405 °, the main cam 18 of the cylinder # 2 is further slid by 10 mm in the axial direction of the camshaft 12. That is, it slides 40 mm from the displacement start position. By sliding 40 mm, the cam with which the roller 34 of the cylinder # 2 is in sliding contact is switched from the main cam 18 to the sub cam 20. The cam width of the main cam 18 is designed so that the cam that slides 40 mm from the displacement start position and is in sliding contact with the roller 34 of the cylinder # 4 is switched to the sub cam 20.

  As shown in FIG. 5E, in a state where the camshaft 12 is rotated by about 405 °, all the cylinders # 1 to # 4 are deactivated. The cylinder # 1 is in a state where the roller 34 is slid by 40 mm on the auxiliary cam 16, and the cylinders # 3 and # 4 are also slid by 30 mm and 20 mm on the auxiliary cams 24 and 28, respectively.

  As described above, according to the configuration of the present embodiment shown in FIGS. 3 to 5, the rotational force of the camshaft 12 is increased by inserting the switching pin 60 into the suspension spiral groove 56 in the suspension actuator 62. By utilizing this, the cam of each cylinder can be slid. In addition, the cam width of the main cam of each cylinder is designed to be wide in the order of valve stop, and the distance from the displacement start position to the switching to the sub cam is increased, so that one pause actuator 62 and the pause spiral groove 56 The cams of the cylinders can be switched in the order of the explosion stroke so that the cylinders can be brought into a resting state. Therefore, the number of actuators and the increase in EDU that controls the actuators can be suppressed, and the cost can be reduced. In addition, according to this configuration, the camshaft 12 is reliably displaced by a displacement amount corresponding to the rotation angle of the camshaft 12 defined in the suspension spiral groove 56. Therefore, regardless of the rotational speed of the camshaft 12, it is possible to reliably switch to the sub cam in the base circle section of the main cam. Further, since the main cam and the sub cam of each cylinder can be slid using the rotational force of the camshaft 12, the actuator can be downsized and the thrust can be reduced.

  As shown in FIG. 5 (E), when the ECU 50 detects a normal operation request after entering the resting state, the ECU 50 turns on the return actuator 66. The return actuator 66 is driven, and the switching pin 64 is engaged with the return spiral groove 58. The return spiral groove 58 is formed opposite to the resting spiral groove 56 (FIG. 5). Therefore, the return spiral groove 58 displaces the camshaft 12 in the left direction of FIG. 5 from the state of FIG. 5E to the state of FIG. 5A with the switching pin 64 inserted. As a result, the cam slidingly contacting the roller 34 of each cylinder in the order of cylinders # 2-> # 4-> # 3-> # 1 is switched from the secondary cam to the main cam, and normal operation is restored.

  In the second embodiment described above, the camshaft 12 is the “camshaft” in the first invention, and the main cams 14, 18, 22, 26 are the “first cam portion” in the first invention. The auxiliary cams 16, 20, 24, 28 are the “second cam portion” in the first invention, the valve 36 is the “valve” in the first invention, and the rocker arm 30 and the roller 34 are the first invention. The helical grooves 56 and 58, the switching pins 60 and 64, and the actuators 62 and 66 correspond to the “displacement means” in the first invention, respectively.

Embodiment 3 FIG.
[System Configuration of Embodiment 3]
Next, a third embodiment of the present invention will be described with reference to FIGS. The system of the present embodiment can be realized by configuring the spiral grooves and the cam widths of the main cam and the sub cam as shown in FIGS. 6 to 8 in the configuration shown in FIG.

  In the second embodiment described above, the switching pin 60 is engaged with the helical spiral groove 56 in response to the valve stop request. The camshaft 12 is displaced using the rotational force of the camshaft 12, and the cylinders # 1 to # 4 can be deactivated while the camshaft 12 rotates once. However, since a large load is applied to the resting spiral groove 56, it is desired to improve its durability. Therefore, in the present embodiment, the inclination of the spiral groove is designed to be gentle with respect to the circumferential direction in accordance with the cam switching period and switching order.

  FIG. 6 is a diagram showing a first example in which the four-cylinder cam is switched by two rotations of the camshaft in the third embodiment of the present invention. In the configuration of the first example, the cam widths of the main cam 18 of the cylinder # 2 and the main cam 26 of the cylinder # 4 in FIG. 3 are replaced, and the sub cam 20 of the cylinder # 2 and the sub cam 28 of the cylinder # 4 The cam width has been replaced. The suspension spiral grooves 56 and 58 are configured to sequentially switch the four-cylinder cam by rotating the camshaft 12 twice. Assuming that the camshaft 12 is sequentially switched to a 4-cylinder cam with two rotations of the camshaft 12, the average inclination of the spiral groove is 0 divided by the displacement distance 40 mm of the camshaft 12 divided by the rotation angle 720 ° for two camshaft rotations. 0.056 mm / °. This is an inclination in which the camshaft 12 is displaced by 0.056 mm when the camshaft 12 rotates by 1 °.

  6 is configured to switch the cam that is in sliding contact with the roller 34 of each cylinder from the main cam to the sub cam in the switching order of # 1 → # 3 → # 2 → # 4. . Similarly to the one shown in FIG. 4, the sliding distance for each cylinder is 10 mm, and the auxiliary cam is switched to the base circle of the main cam of each cylinder.

  The idle spiral groove 56 shown in FIG. 6 is a position where the cam which slides on the roller 34 of the cylinder # 1 is displaced during the valve closing period of the cylinder # 1 and the valve opening period of the cylinders # 3 and # 4. Then, the main cam 14 is switched to the sub cam 16. Further, during the valve closing period of the cylinder # 3 and during the valve opening period of the cylinders # 4 and # 2, the cam that slides 20 mm from the displacement start position and slides on the roller 34 of the cylinder # 3 from the main cam 22. Switch to the secondary cam 24. Further, the cam that is in sliding contact with the roller 34 of the cylinder # 2 is switched from the main cam 18 to the sub cam 20 during the valve closing period of the cylinder # 2 and during the valve opening period of the cylinders # 1 and # 3. After switching in cylinder # 2, it waits for cylinder # 4 to close. Therefore, the resting spiral groove 56 has a non-sliding section that only rotates in the circumferential direction without displacing the camshaft 12 in the axial direction. Thereafter, during the valve closing period of cylinder # 4 and during the valve opening period of cylinders # 2 and # 1, the cam that slides on roller 34 of cylinder # 4 is switched from main cam 26 to sub cam 28.

  According to the configuration shown in FIG. 6, the cam that is in sliding contact with the roller 34 of each cylinder is set in the main cam while the inclination of the helical groove 56 for pause is gently set with respect to the circumferential direction as compared with the configuration shown in FIG. 4. Can be sequentially slid from the base circle to the base circle of the secondary cam. Therefore, the effect similar to Embodiment 1 and 2 can be acquired, improving durability of a spiral groove. In addition, since the inertial force is increased in the configuration in which the cam width of the camshaft 12 is widened, the configuration of the present embodiment works particularly favorably.

  Note that when the resting spiral groove 56 shown in FIG. 6 is used, the return spiral groove 58 also has a gentle inclination of the spiral-like groove as in the resting spiral groove 56, and the groove faces in the reverse direction. To form.

  FIG. 7 is a diagram illustrating a second example in which the four-cylinder cam is switched by two rotations of the camshaft in the third embodiment of the present invention. In this configuration, the cam widths of the main cam 14 of the cylinder # 1 and the main cam 18 of the cylinder # 2 in FIG. 3 are replaced, and the cam widths of the sub cam 20 of the cylinder # 2 and the sub cam 28 of the cylinder # 4 are replaced. ing. Further, the spiral grooves 56 and 58 are configured to sequentially switch the 4-cylinder cam by rotating the camshaft 12 twice.

  7 is configured to switch the cam that is slidably in contact with the roller 34 of each cylinder from the main cam to the sub cam in the switching order of # 2, # 3, # 4, and # 1. . Further, similarly to the one shown in FIG. 4, the slide distance required for the cam switching for each cylinder is 10 mm, and the sub-cam is switched at the base circle portion of the main cam of each cylinder.

  The idle spiral groove 56 shown in FIG. 7 is a position where the cam that slides on the roller 34 of the cylinder # 2 is displaced during the valve closing period of the cylinder # 2 and the valve opening period of the cylinders # 3 and # 4. Then, the main cam 18 is switched to the sub cam 20. Further, during the valve closing period of the cylinder # 3 and during the valve opening period of the cylinders # 4 and # 2, the cam that slides 20 mm from the displacement start position and slides on the roller 34 of the cylinder # 3 from the main cam 22. Switch to the secondary cam 24. Further, the cam that is in sliding contact with the roller 34 of the cylinder # 4 is switched from the main cam 26 to the sub cam 28 during the valve closing period of the cylinder # 4 and during the valve opening period of the cylinders # 1 and # 3. Subsequently, the cam that is in sliding contact with the roller 34 of the cylinder # 1 is switched from the main cam 14 to the sub cam 16 during the valve closing period of the cylinder # 1 and during the valve opening period of the cylinders # 3 and # 4.

  According to the configuration shown in FIG. 7, the cam that is in sliding contact with the roller 34 of each cylinder is set to the main cam while the inclination of the spiral groove 56 for pause is set gently relative to the circumferential direction as compared with the configuration shown in FIG. 4. The base cam can be sequentially slid to the secondary cam. Therefore, the same effect as in FIG. 6 can be obtained. Further, according to the configuration shown in FIG. 7, since the non-sliding section in FIG. 6 is not provided in the suspension spiral groove 56, the period until all the cylinders are switched can be made earlier than the configuration shown in FIG. 6.

  In the case where the resting spiral groove 56 shown in FIG. 7 is used, the return spiral groove 58 also has a gentle inclination of the spiral-like groove, like the resting spiral groove 56, and the groove is in the reverse direction. To form.

  FIG. 8 is a diagram illustrating an example of switching a 4-cylinder cam by three rotations of the camshaft in the third embodiment of the present invention. In this configuration, the cam widths of the main cam 18 and the sub cam 20 of the cylinder # 2 in FIG. 3 are changed to the cam widths of the main cam 22 and the sub cam 24 of the cylinder # 3. Further, the cam widths of the main cam 22 and the sub cam 24 of the cylinder # 3 are changed to the cam widths of the main cam 26 and the sub cam 28 of the cylinder # 4. Further, the cam widths of the main cam 26 and the sub cam 28 of the cylinder # 4 are changed to the cam widths of the main cam 18 and the sub cam 20 of the cylinder # 2 in FIG. Further, the spiral grooves 56 and 58 are configured to sequentially switch the four-cylinder cam by rotating the camshaft 12 three times. Assuming that the camshaft 12 is switched three times and the cams of the four cylinders are sequentially switched, the inclination of the spiral groove is 0.037 mm obtained by dividing the displacement distance 40 mm of the camshaft 12 by the rotation angle 1080 ° corresponding to the rotation of the camshaft 12. It is expressed as / °. This is an inclination that the camshaft 12 is displaced by 0.037 mm when the camshaft 12 rotates by 1 °.

  The configuration of the suspension spiral groove 56 shown in FIG. 8 is to switch the cam that is in sliding contact with the roller 34 of each cylinder from the main cam to the sub cam in the switching order of # 1 → # 2 → # 4 → # 3. . Similarly to FIG. 4, the slide distance required for cam switching for each cylinder is 10 mm, and switching to the sub cam is performed at the base circle portion of the main cam of each cylinder.

  The idle spiral groove 56 shown in FIG. 8 displaces the cam that is in sliding contact with the roller 34 of the cylinder # 1 during the valve closing period of the cylinder # 1 and the valve opening period of the other three cylinders (about 270 °). The main cam 14 is switched to the sub cam 16 by sliding 10 mm from the start position. Further, during the valve closing period of the cylinder # 2 and the valve opening period of the other three cylinders, the cam that slides 20 mm from the displacement start position and is in sliding contact with the roller 34 of the cylinder # 2 is transferred from the main cam 18 to the sub cam 20. Switch to. Further, during the valve closing period of the cylinder # 4 and the valve opening period of the other three cylinders, the cam that slides on the roller 34 of the cylinder # 4 is switched from the main cam 26 to the sub cam 28. Subsequently, the cam that slides on the roller 34 of the cylinder # 3 is switched from the main cam 22 to the sub cam 24 during the valve closing period of the cylinder # 3 and the valve opening period of the other three cylinders.

  According to the configuration shown in FIG. 8, the entire cam base circle section of about 270 ° can be used for each cylinder, and the cam can be gently slid and switched. Therefore, the durability of the spiral groove can be further improved as compared with the configurations of FIGS.

  When the resting spiral groove 56 shown in FIG. 8 is used, the return spiral groove 58 also has a gentle inclination of the spiral-like groove as in the resting spiral groove 56, and the groove is in the reverse direction. To form.

  In the third embodiment described above, the camshaft 12 is the “camshaft” in the first invention, and the main cams 14, 18, 22, 26 are the “first cam portion” in the first invention. The auxiliary cams 16, 20, 24, 28 are the “second cam portion” in the first invention, the valve 36 is the “valve” in the first invention, and the rocker arm 30 and the roller 34 are the first invention. In the “transmission member”, the spiral grooves 56 and 58 are the “helical groove” in the fifth invention, the switching pins 60 and 64 are the “switching pin” in the fifth invention, and the actuators 62 and 66 are This corresponds to the “actuator” in the fifth aspect of the invention.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 10 Variable valve apparatus 12 Camshaft 14 Main cam 14a of cylinder # 1 Base circular part 14b Nose part 16 Secondary cam 18 of cylinder # 1 Main cam 20 of cylinder # 2 Secondary cam 22 of cylinder # 2 Cylinder # 3 Main cam 24 cylinder # 3 secondary cam 26 cylinder # 4 main cam 28 cylinder # 4 secondary cam 30 two-valve drive rocker arm 32 rocker shaft 34 roller 36 valve 42 actuator 50 ECU
56 Resting spiral groove 58 Returning spiral groove 60, 64 Switching pin 62 Resting actuator 66 Restoring actuator

Claims (5)

A rotationally driven camshaft;
A plurality of cams provided on the camshaft, each having a first cam portion and a second cam portion having different profiles arranged adjacent to each other;
A transmission member that selectively contacts one of the first cam portion and the second cam portion, and transmits the acting force from the first cam portion or the second cam portion to the valve;
Displacement means for relatively displacing the camshaft and the transmission member in the axial direction of the camshaft;
The width of the second cam portion with respect to the width of the first cam portion is different in the plurality of cams;
A variable valve operating apparatus for an internal combustion engine characterized by the above.   2. The variable valve operating apparatus for an internal combustion engine according to claim 1, wherein a width of the first cam portion is set wider as a cam having a slower switching order.   3. The variable valve operating apparatus for an internal combustion engine according to claim 2, wherein the switching order is the same order as the explosion order.   4. The camshaft cam according to claim 1, wherein one of the first cam portion and the second cam portion is a rest cam portion including an arcuate base circle portion coaxial with the camshaft. A variable valve operating device for an internal combustion engine. The displacement means is
Displace the camshaft to a displacement end position where the cam portion that contacts the transmission member of the plurality of cams switches from the first cam portion to the second cam portion,
A spiral groove formed on an outer peripheral surface of a rotating body that rotates together with the camshaft, and guides the camshaft in its axial direction;
A switching pin that can be inserted into and removed from the spiral groove;
An actuator for inserting the switching pin into the spiral groove,
The spiral groove is
Guiding the camshaft from the position where the switching pin is inserted into the spiral groove to the displacement end position while the camshaft is rotated longer than one rotation;
The variable valve operating apparatus for an internal combustion engine according to any one of claims 1 to 4.

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