JP2013019358A - Variable valve device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable valve device which can change opening/closing times of a plurality of valves.SOLUTION: The variable valve device 11 comprises the plurality of air intake valves 15, 16 per cylinder. The air intake valves 15, 16 are driven by first and second cams 25, 26 so as to be openable and closable. An actuator 13 for changing phases of the first and second cams 25, 26 has a housing 41 and a rotor 42. The rotor 42 can be turned to an advanced side and a retarded side within a prescribed phase variable range with respect to the housing 41. The actuator 13 is controlled by a control part 61 so that both the first and second cams 25, 26 are simultaneously changed in phase in a phase variable region at the advanced side with an initial position (intermediate position being a middle between the most retarded angle and the most advanced angle) in the phase variable range as a boundary. In a phase variable region at the retarded side in the phase variable range, it is controlled so that only one of the first and second cams 25, 26 is changed in phase, and the phase variable region at the retarded side is formed larger than the phase variable region at the advanced side.

Description

  The present invention relates to a variable valve operating apparatus for opening and closing an intake valve or the like of an engine.

  2. Description of the Related Art A variable valve gear that can change the opening / closing timing of an intake valve or an exhaust valve in accordance with the operating state of an engine is known. For example, as disclosed in Patent Documents 1 and 2, a variable valve gear configured to be able to change the rotation phase of a camshaft with respect to a sprocket that rotates in synchronization with a crankshaft is known. It is. In this type of variable valve operating apparatus, the opening / closing timing of the intake valve can be changed to the advance side or the retard side by changing the phase of the camshaft by an actuator. As actuators, hydraulic or electric actuators are known.

  In addition, in an engine having a plurality of intake valves for each cylinder (cylinder), there has also been proposed a variable valve apparatus capable of changing the phases of the intake valves for each cylinder. This type of variable valve operating apparatus is configured such that the phases of the plurality of intake valve cams can be changed independently of each other with respect to the camshaft. For this reason, a first actuator for changing the phase of one cam and a second actuator for changing the phase of the other cam are usually used.

JP 2000-179111 A JP 2001-50063 A

  As described above, in the variable valve operating apparatus having a plurality of intake valves per cylinder, a structure in which one intake valve cam and the other intake valve cam are independently driven by separate actuators. If this is the case, the valve operating apparatus will be increased in size, and a large drive energy may be required when the phases of the valves are changed simultaneously. In particular, when it is desired to make a difference in phase change between the advance side and the retard side, it is not always necessary to change the phase of all the cams. In such a case, the conventional variable valve operating apparatus has room for improvement in minimizing the movement of each cam.

  Accordingly, it is an object of the present invention to provide a variable valve operating apparatus capable of setting the opening / closing timing of each valve in a preferable state in accordance with the operating state of the engine in an engine having at least two intake valves per cylinder.

  A variable valve operating apparatus according to the present invention includes a driving side rotating body that rotates in synchronization with a crankshaft of an engine, a first driven side rotating body that includes a first cam for driving the first valve, A second driven rotary body including a second cam for driving the two valves, and the first and second driven rotary bodies are advanced or retarded with respect to the drive rotary body And an actuator section that changes within a predetermined phase variable range, and a control means. The control means drives the actuator unit so as to simultaneously change the phase of the first cam and the second cam in the phase variable region on one side with respect to the intermediate position in the phase variable range, In the phase variable region, the actuator unit is driven to change only one phase of the first cam and the second cam, and the size of the phase variable region on the one side and the phase variable region on the other side is increased. It makes things different from each other.

  An example of the first and second cams is for driving the first and second intake valves provided in one cylinder, and the control means is an advance side of the phase variable range. In the phase variable region, the phases of the first cam and the second cam are simultaneously changed. In the phase variable region on the retard side of the phase variable range, one of the first cam and the second cam is changed. The phase is changed. Further, the phase variable region on the retard angle side may be made larger than the phase variable region on the advance angle side.

  According to the present invention, in the variable valve operating apparatus having at least two cams for the intake valves for each cylinder, each actuator is moved to the advance side and the retard side by one actuator unit. It is possible to make a difference in the phase change depending on the case, and advance or retard operation can be performed according to the operating condition of the engine.

1 is a cross-sectional view schematically showing a variable valve operating apparatus according to one embodiment of the present invention. Sectional drawing which cut | disconnected the actuator part of the variable valve apparatus shown by FIG. 1 in the direction orthogonal to the axis line of a shaft member. Sectional drawing which shows the actuator part at the time of the variable valve apparatus shown by FIG. 1 act | operating to an advance side. Sectional drawing which shows the actuator part at the time of the variable valve apparatus shown by FIG. The schematic diagram for demonstrating the action | operation of the actuator part of the variable valve apparatus shown by FIG. The schematic diagram for demonstrating the state which the actuator part of the variable valve apparatus shown by FIG. 1 switched to the 1st phase variable mode. The schematic diagram for demonstrating the state which the actuator part of the variable valve apparatus shown by FIG. 1 moved to the advance side. The schematic diagram for demonstrating the state which the actuator part of the variable valve apparatus shown by FIG. 1 switched to the 2nd phase variable mode. The schematic diagram for demonstrating the state which the actuator part of the variable valve apparatus shown by FIG. 1 moved to the retard side. The figure which shows the relationship between the lift amount and crank angle of the intake valve of the variable valve apparatus shown by FIG.

Hereinafter, a variable valve operating apparatus according to one embodiment of the present invention will be described with reference to FIGS.
FIG. 1 schematically shows a variable valve gear 11 provided in a cylinder head 10 of an engine. This variable valve operating apparatus 11 has an assembly cam shaft 12 and a hydraulic actuator 13 which will be described later. This engine has at least two intake valves 15 and 16 and an exhaust valve (not shown) for each cylinder. For example, the intake valves 15 and 16 are opened and closed by the variable valve device 11 shown in FIG.

  The assembly cam shaft 12 includes a double-structured shaft member 20 including an outer shaft 21 and an inner shaft 22, and first and second cams 25 and 26 assembled to the shaft member 20. The outer shaft 21 has a pipe shape, and an inner shaft 22 is rotatably provided in the outer shaft 21.

  The shaft member 20 has an axis X1 extending in the longitudinal direction. The inner shaft 22 can rotate (relatively rotate) about the axis X <b> 1 with respect to the outer shaft 21. The outer shaft 21 is rotatably supported by bearings 30, 31, 32 provided on the cylinder head 10. A flange portion 21 a is provided at one end portion (the actuator portion 13 side) of the outer shaft 21.

  The first cam 25 is fixed to the outer shaft 21, and the first cam 25 and the outer shaft 21 rotate integrally. A cam surface 25 a having a cam profile for opening and closing the first intake valve 15 is formed on the outer periphery of the first cam 25.

  The second cam 26 can rotate around the axis X <b> 1 with respect to the outer shaft 21. The second cam 26 is fixed to the inner shaft 22 by a connecting member 35 so that the second cam 26 and the inner shaft 22 rotate integrally. The connecting member 35 is fixed to the inner shaft 22 and protrudes from the opening 36 formed in the outer shaft 21 in the radial direction of the outer shaft 21. A cam surface 26 a having a cam profile for opening and closing the second intake valve 16 is formed on the outer periphery of the second cam 26. The second cam 26 has a cylindrical portion 26b extending in the direction of the axis X1, and a cam lobe 26c is formed at the end of the cylindrical portion 26b.

  FIG. 2 is a cross-sectional view schematically showing the actuator unit 13 cut in a direction perpendicular to the axis X1 of the shaft member 20. As shown in FIG. The actuator unit 13 includes a sprocket 40 that is rotationally driven by an engine crankshaft 39 (shown in FIG. 1), a housing 41 provided on the sprocket 40, a rotor 42 housed in the housing 41, and the like. Yes. The sprocket 40 rotates in synchronization with the crankshaft 39 by a power transmission member 45 (shown in FIG. 1) such as a chain or a timing belt.

  Inside the housing 41, a plurality of advance vane chambers 50 and a plurality of retard vane chambers 51 are formed by the rotor 42. The advance vane chamber 50 and the retard vane chamber 51 are connected to the hydraulic unit 60 via a retard oil passage 52 and an advance oil passage 53, respectively. The hydraulic unit 60 is controlled by a control unit 61 such as an electronic control unit (ECU), and can supply hydraulic pressure to the retard oil passage 52 and the advance oil passage 53 in accordance with the operating condition of the engine. Yes.

  For example, when the hydraulic pressure generated by the hydraulic unit 60 is supplied from the retarded oil passage 52 to the retarded vane chamber 51, the rotor 42 rotates relative to the housing 41 toward the retarded side. Further, when the hydraulic pressure is supplied from the advance oil passage 53 to the advance vane chamber 50, the rotor 42 rotates to the advance side with respect to the housing 41.

  The housing 41 is fixed to the sprocket 40. For this reason, the housing 41 rotates integrally with the sprocket 40. The rotor 42 is fixed to the inner shaft 22 with bolts 55. For this reason, the rotor 42 rotates integrally with the inner shaft 22. When the rotor 42 is rotated toward the retard side or the advance side with respect to the housing 41, the phase of the outer shaft 21 and the inner shaft 22 (relative position about the axis X1) changes, and as a result, the phases of the cams 25 and 26 are changed. Will change.

  When the rotor 42 is in an intermediate position between the most retarded angle and the most advanced angle, that is, at the initial position, such as when the engine is started or when the engine is rotating at a low speed, for example, By fitting in the pin fitting hole 57 on the sprocket 40 side, the sprocket 40 and the rotor 42 are fixed to each other via the lock pin 56.

  The sprocket 40, the housing 41, and the like constitute a drive side rotating body 70 that is driven by a crankshaft 39. The sprocket 40, which is a component of the drive-side rotator 70, rotates in synchronization with the crankshaft 39 via the power transmission member 45. Therefore, the phase of the drive side rotator 70 corresponds to the phase of the crankshaft 39.

  On the other hand, the outer driven shaft 21, the first cam 25, and the like constitute a first driven-side rotating body 71. Since the first cam 25 is fixed to the outer shaft 21, the first cam 25 and the outer shaft 21 rotate integrally around the axis X1. The flange portion 21 a provided at the end portion of the outer shaft 21 can be rotated relative to the sprocket 40 around the axis X <b> 1.

  The inner shaft 22, the second cam 26, the connecting member 35, the rotor 42, and the like constitute a second driven-side rotating body 72. That is, the inner shaft 22, the second cam 26, and the rotor 42, which are components of the second driven-side rotator 72, rotate together around the axis X1.

  The first driven-side rotator 71 and the second driven-side rotator 72 are driven by the hydraulic pressure supplied from the hydraulic unit 60 so that the phase around the axis line X1 (advance or retard) with respect to the drive-side rotator 70 is increased. ) Can be changed. That is, the hydraulic unit 60 and the control unit 61 constitute an example of a control unit for changing the phases of the first driven side rotating body 71 and the second driven side rotating body 72 with respect to the driving side rotating body 70. ing.

  The variable valve apparatus 11 includes a switching mechanism 80 for switching between the first phase variable mode and the second phase variable mode. Here, the first phase variable mode is a mode in which the phase of the first driven-side rotating body 71 and the second driven-side rotating body 72 changes simultaneously with respect to the driving-side rotating body 70. The second variable phase mode is a mode in which the phase of only the second driven rotating body 72 changes with respect to the driving side rotating body 70.

  The switching mechanism 80 has a switching member 81. An example of the switching member 81 is a cylindrical pin that is movable in the direction of the axis X1 of the shaft member 20. The switching member 81 includes a first hole 82 formed in the sprocket 40, a second hole 83 formed in the flange portion 21 a of the outer shaft 21, and a first hole formed in the cam lobe 26 c of the second cam 26. 3 so as to be movable in the direction parallel to the axis X1 so as to move in the direction of the axis X1 according to the hydraulic pressure supplied from the hydraulic unit 60 to the retard oil passage 52 or the advance oil passage 53. It has become.

  FIG. 3 shows a state where the switching member 81 has moved to the first position (first phase variable mode). When the switching member 81 is in the first position (first phase variable mode), the switching member 81 is fitted into the hole 83 of the outer shaft 21 and the hole 84 of the second cam 26 and the hole 82 of the sprocket 40. Get out of. As a result, the outer shaft 21 and the second cam 26 are coupled to each other, and the outer shaft 21 and the second cam 26 are separated from the sprocket 40. For this reason, the first cam 25 and the second cam 26 fixed to the outer shaft 21 can be rotated around the axis X1 integrally with each other.

  FIG. 4 shows a state where the switching member 81 has moved to the second position (second phase variable mode). When the switching member 81 is in the second position (second phase variable mode), the switching member 81 is fitted into the hole 82 of the sprocket 40 and the hole 83 of the outer shaft 21 and the hole 84 of the second cam 26. Get out of. As a result, the sprocket 40 and the outer shaft 21 are coupled to each other, and the second cam 26 is separated from the outer shaft 21, so that the second cam 26 can be rotated about the axis X1.

  FIGS. 5 to 9 are schematic views for explaining the operation of the first and second driven-side rotating bodies 71 and 72. FIG. Since these drawings are schematic diagrams for the sake of convenience in explaining the operation of the actuator unit 13, the shape and layout are different from those of the actuator unit 13 shown in FIGS.

  FIG. 5 is a schematic diagram corresponding to FIG. 1 and shows an initial mode of the actuator unit 13, that is, an initial position which is an intermediate position between the most retarded angle and the most advanced angle. In the initial mode, the switching member 81 is fitted in the hole 82 of the sprocket 40 and the hole 83 of the outer shaft 21. An example of the initial mode is when the engine is started or when the engine is rotating slowly (during idling), and since the hydraulic pressure has not increased, the lock pin 56 is fitted in the pin fitting hole 57 of the sprocket 40. Therefore, in the initial mode, the first driven side rotating body 71 and the second driven side rotating body 72 are locked with respect to the driving side rotating body 70, and the first cam 25 and the second cam 26 are The initial position (initial) remains unchanged without any phase change.

  FIGS. 6 and 7 are schematic views corresponding to FIG. 3, respectively, and show the first phase variable mode of the actuator unit 13. In the first phase variable mode, as shown in FIG. 6, the switching member 81 comes out of the hole 82 of the sprocket 40 by the hydraulic pressure supplied from the advance oil passage 53, and the switching member 81 is connected to the hole 83 of the outer shaft 21. 2 is fitted into the hole 84 of the cam 26. Thereby, the first driven side rotating body 71 and the second driven side rotating body 72 are coupled to each other, and the first driven side rotating body 71 and the second driven side with respect to the driving side rotating body 70 are combined. The rotating body 72 is separated. Therefore, the first cam 25 and the second cam 26 can be rotated together.

  In this first phase variable mode, when hydraulic pressure is supplied to the advance oil passage 53 as shown in FIG. 7, the first driven-side rotator 71 and the second driven-side rotator 72 simultaneously The first cam 25 and the second cam 26 move to the advance side by rotating to the advance side in the phase variable region T1 with respect to the drive side rotating body 70.

  FIGS. 8 and 9 are schematic diagrams corresponding to FIG. 4, respectively, and show the second phase variable mode of the actuator unit 13. In the second phase variable mode, as shown in FIG. 8, the switching member 81 comes out of the hole 84 of the rotor 42 by the hydraulic pressure supplied from the retarded oil passage 52, and the switching member 81 is fitted into the hole 82 of the sprocket 40. To do. As a result, the driving-side rotator 70 and the first driven-side rotator 71 are coupled to each other, and the second driven-side rotator 72 is separated from the first driven-side rotator 71. Become. Therefore, only the second driven-side rotator 72 can be rotated with respect to the drive-side rotator 70.

  In this second variable phase mode, as shown in FIG. 9, when hydraulic pressure is supplied to the retarded oil passage 52, the first driven rotor 71 is moved to the initial position (between the most retarded angle and the most advanced angle). Only the second driven-side rotating body 72 rotates to the retard side in the phase variable region T2 with respect to the driving-side rotating body 70, while remaining at the intermediate position). Only moves to the retard side.

  FIG. 10 shows the relationship between the lift amount (opening / closing timing) of the first and second valves 15 and 16 of the variable valve operating apparatus 11 of the embodiment and the crank angle. As described above, the first cam 25 and the second cam 26 are moved in the phase variable region T1 on the advance side with respect to the drive side rotating body 70 including the sprocket 40 and the housing 41. On the retard side, only the second cam 26 moves in the retarded phase variable region T2. Therefore, the total phase variable range S is a total amount of the phase advance region T1 on the advance side and the phase variable region T2 on the retard side. The advance-angle-side phase variable region T1 and the retard-angle-side phase variable region T2 are set adjacent to each other with the initial position as a boundary.

  The retarded phase variable region T2 is larger than the advanced phase variable region T1. As an example, the phase variable region T1 (crank angle 80) is set so that the phase variable region T1 on the advance side corresponds to a crank angle of 35 °, whereas the phase variable region T2 on the retard side corresponds to 45 ° of the crank angle. The distribution ratio of the variable range is set between the advance side and the retard side with the initial position as a boundary.

  By doing so, it is possible to make the retarded phase variable region T2 as large as possible within the limited phase variable range S, and the second intake valve 16 driven by the second cam 26 is closed. The time delay can be greatly increased. In this case, for example, it is possible to reduce pump loss and improve fuel efficiency. In this example, the retarded phase variable region T2 is larger than the advanced phase variable region T1, so that more hydraulic pressure is required during retarded driving than during advanced drive. Since the part 13 only needs to move the second driven-side rotating body 72 (second cam 26), it is possible to suppress a decrease in hydraulic pressure and ensure responsiveness.

  For example, when emphasizing engine performance, the first cam 25 and the second cam 26 are simultaneously moved to the advance angle side in the first phase variable mode to cope with engine output. be able to. On the other hand, when emphasizing fuel efficiency, the control unit 61 can perform control such that only the second cam 26 is phase-shifted to the retard side in the second phase variable mode.

  As indicated by a two-dot chain line Z in FIG. 10, the cam profiles of the cams 25 and 26 may be different from each other so that the valve closing timings of the first cam 25 and the second cam 26 are shifted. By doing this, the EGR backflow into the intake pipe is made uniform when taking in internal exhaust gas recirculation (EGR), and the gas made uniform in the cylinder is pushed out from one intake valve when the valve is closed. A swirl can be generated by exhaust in the cylinder, and mixing can be improved and combustion can be improved.

  As another embodiment, the phase of the cam profiles of the first and second cams 25 and 26 may be shifted from the initial position. The direction of shifting is either the advance side or the retard side. Also in this case, the first cam 25 and the second cam 26 are simultaneously moved by the same phase amount within the phase advance region T1 on the advance side as in the above embodiment. Only the second cam 26 moves within the retarded phase variable region T2. The retarded phase variable region T2 is larger than the advanced phase variable region T1. According to this embodiment, by shifting the phases of the respective cams for opening and closing the first and second intake valves from the beginning, for example, when taking in the internal EGR by re-inhaling the exhaust, one of the intake valves makes the cylinder It is possible to generate a swirl by intake air, improve combustion, and reduce pump loss by internal EGR.

  In carrying out the present invention, a variable valve operating device such as a driving-side rotating body, a first driven-side rotating body, a second driven-side rotating body, as well as a specific shape and configuration of an actuator unit, a cam, etc. Needless to say, the present invention can be implemented by variously changing the specific form such as the shape and arrangement of the constituent elements, or the distribution ratio between the phase variable region on the advance side and the phase variable region on the retard side.

  DESCRIPTION OF SYMBOLS 11 ... Variable valve apparatus, 13 ... Actuator part, 20 ... Shaft member, 21 ... Outer shaft, 22 ... Inner shaft, 25 ... 1st cam, 26 ... 2nd cam, 40 ... Sprocket, 42 ... Rotor, 56 DESCRIPTION OF SYMBOLS ... Lock pin, 61 ... Control part, 70 ... Drive side rotary body, 71 ... 1st driven side rotary body, 72 ... 2nd driven side rotary body, 80 ... Switching mechanism, 81 ... Switching member.

Claims (3)

A driving side rotating body that rotates in synchronization with the crankshaft of the engine;
A first driven rotary body including a first cam for driving the first valve;
A second driven rotary body including a second cam for driving the second valve;
An actuator unit that changes the first and second driven rotating bodies to the advance side or the retard side within a predetermined phase variable range with respect to the driving side rotating body;
The actuator unit is driven to simultaneously change the phase of the first cam and the second cam in the phase variable region on one side with respect to the intermediate position in the phase variable range, and the phase variable region on the other side The actuator unit is driven so as to change only one phase of the first cam and the second cam, and the phase variable region on the one side and the phase variable region on the other side are made different from each other. A variable valve operating apparatus comprising a control means.   The first and second cams are for driving first and second intake valves provided in one cylinder, and the control means has a phase on the advance side in the phase variable range. In the variable region, the phases of the first cam and the second cam are changed simultaneously, and in the phase variable region on the retard side of the phase variable range, the phase of one of the first cam and the second cam is changed. The variable valve operating device according to claim 1, wherein the variable valve operating device is changed.   The variable valve operating apparatus according to claim 2, wherein the phase variable region on the retard side is larger than the phase variable region on the advance side.

Images