JP2008063950A - Solenoid control valve and hydraulic drive unit using the solenoid control valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such a problem of a conventional solenoid control valve that an accuracy of opening/closing each port is decreased because a spool valve cannot be retained stably at an intermediate movement position. <P>SOLUTION: The solenoid control valve of the invention includes an solenoid drive section 37 capable of proportionally controlling driving force according to an energy amount, a spool valve 38 for selectively opening/closing a supply port 36a, first and second outlet ports 36b, 36c and a drain port 36d according to the movement position in the internal axial direction of a valve body 36 to thereby switch a flow channel, and first and second spring members 49, 50 for urging the spool valve in another direction. The spool valve is moved by a predetermined distance in one direction against the spring force of the first spring member when the solenoid drive section is energized and an engagement portion 46 makes contact with a second spring retainer 51 so that the spring force of the second spring member starts acting on the spool valve so as to retain the spool valve at the intermediate position until the energy amount increases to reach a predetermined value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electromagnetic control valve used for, for example, a variable valve lift mechanism of an internal combustion engine that variably controls a valve lift of an intake side or exhaust side engine valve of the internal combustion engine in accordance with an engine operating state.

  As this type of conventional electromagnetic control valve, for example, those described in Patent Documents 1 and 2 below are known.

  An electromagnetic control valve described in Patent Document 1 is provided in a cylinder head of an internal combustion engine, and controls a valve pause mechanism that switches between a valve pause state and a valve operation state, and includes a bottomed cylindrical valve body, A spool valve and a pilot valve are provided in the valve body so as to be movable in the axial direction, and a solenoid for driving the pilot valve.

  The pilot valve opens and closes the ball valve body by turning off and exciting the solenoid, and selectively opens and closes the input and output ports via the spool valve, thereby allowing the valve pause mechanism to provide a valve pause state hydraulic pressure. And switching control to supply and discharge the hydraulic pressure in the valve operating state.

  On the other hand, the electromagnetic control valve described in Patent Document 2 is applied to a valve timing control mechanism that controls the opening / closing timing of an engine valve of an internal combustion engine, and is provided inside the valve body so as to be movable in the axial direction. The spool valve is mainly composed of a spool valve and a solenoid that moves the spool valve in one direction via a plunger.

Then, the solenoid valve is turned off from the controller in accordance with the engine operating state, and the spool valve moves in the axial direction along with the excitation, so that the plurality of input / output ports and drain ports formed on the peripheral wall of the valve body are relatively Select to switch the hydraulic fluid flow path. Thus, the opening and closing timing of the engine valve is variably controlled by supplying and discharging hydraulic oil to and from the advance and retard oil chambers of the valve timing control mechanism.
Japanese Patent Laid-Open No. 2003-7279 JP-A-9-79195

  However, since the electromagnetic control valve described in Patent Document 1 opens and closes the pilot valve by a solenoid, the spool valve moves on and off in only one direction or two directions. It is not possible to hold the spool valve in an arbitrary movement position simply by making it. Therefore, only two controls, a valve resting state and a valve operating state, can be performed, and it cannot be controlled to an arbitrary state.

  On the other hand, the electromagnetic control valve described in Patent Document 2 can hold the spool valve at an arbitrary moving position by a solenoid, but the position of the spool valve may become unstable due to a disturbance to the solenoid or the like. . If the movement position of the spool valve becomes unstable, the hydraulic oil in the valve body leaks from the high pressure portion to the low pressure portion, and the desired hydraulic pressure cannot be supplied to the advance and retard oil chambers. Such a phenomenon becomes prominent particularly when the axial length of the spool valve is short or when the moving stroke amount in the axial direction is small.

  Further, when a proportional control type that controls the movement of the spool valve in accordance with the energization amount to the solenoid is used as each of the conventional electromagnetic control valves, the spool valve may be controlled to an arbitrary movement position. Although it becomes relatively easy, if a disturbance to the solenoid occurs, the energization amount also changes and the moving position of the spool valve cannot be accurately controlled.

  The present invention has been devised in view of the technical problems of the conventional electromagnetic control valves, and the invention according to claim 1 includes an electromagnetic drive unit capable of proportionally controlling the driving force in accordance with the energization amount. A spool valve that selectively opens and closes a plurality of opening holes in accordance with a movement position in the axial direction, and slides in one direction by the driving force of the electromagnetic driving unit; and the spool valve is driven in the driving direction by the electromagnetic driving unit. Biasing means for biasing from the opposite direction to change the moving position of the spool valve, and the biasing means steps the biasing force according to the moving position of the spool valve by the driving force of the electromagnetic drive unit. It is characterized by the fact that it can be changed dynamically.

  According to this invention, when the spool valve moves in one direction by a predetermined amount against the urging force of the urging means by the proportionally controlled driving force of the electromagnetic driving unit, the urging force of the urging means is stepped from this point. In the period up to a predetermined energization amount of the electromagnetic drive unit, that is, while a predetermined drive force is generated, even if it is affected by a disturbance or the like, the spool is resisted against the drive force. It becomes possible to hold the valve in a stopped state at an intermediate position.

  Thereafter, when the energization amount to the electromagnetic drive unit becomes a predetermined amount or more, the spool valve can be further moved in one direction to a desired position by overcoming the increased biasing force of the biasing means.

  The inventions described in claims 2 and 3 further embody the invention described in claim 1.

  According to a fourth aspect of the present invention, an electromagnetic control valve is applied to a variable valve lift mechanism as a hydraulic drive device that varies a valve lift of an internal combustion engine such as an intake valve, and a hydraulic pump that discharges hydraulic oil; A hydraulic drive device comprising: an electromagnetic control valve that switches a flow path of hydraulic oil pumped from the hydraulic pump to supply and discharge hydraulic pressure to the actuator; and a controller that controls the amount of current supplied to the electromagnetic control valve. The electromagnetic control valve is provided on one end side of the valve body, and is provided with an electromagnetic drive unit capable of proportionally controlling the driving force in accordance with the energization amount, and is provided in the valve body so as to be movable in the axial direction. A spool valve that selectively opens and closes a plurality of supply ports, output ports, and drain ports according to the position to switch the flow path, and the spool valve is slid in a direction opposite to the driving force of the electromagnetic drive unit. And biasing means for said biasing means is characterized in that it is stepwise changeable form the biasing force in accordance with the movement position of the spool valve by the driving force of the electromagnetic drive unit.

  Hereinafter, an embodiment in which an electromagnetic control valve according to the present invention is applied to a variable valve lift mechanism (hydraulic drive device) that variably controls a valve lift amount of an engine valve that is an intake valve or an exhaust valve of an internal combustion engine will be described in detail with reference to the drawings. Describe. In this embodiment, the present invention is applied to an internal combustion engine having two intake valves 1 and 1 per cylinder.

  That is, as shown in FIGS. 7 to 11, a camshaft 1 rotatably supported on a cylinder head is provided with a low speed cam 2 (valve stop cam) for each cylinder and a side portion of the low speed cam 2. 1 and a medium speed cam 5 disposed on the side of the high speed cam 4, respectively, and the low speed cam 3 and the middle are disposed below the cam shaft 2. Two first rocker arms 6 and second rocker arms 7 respectively corresponding to the speed cams 5 are provided. A high-speed cam follower 8 facing the high-speed cam 4 is swingably disposed at the center position between the rocker arms 6 and 7.

  Also, a first linkage switching mechanism 9 is provided between the first rocker arm 6 and the second rocker arm 7 for appropriately linking or releasing the linkages 6 and 7 as well as the second rocker arm 7 and the high speed. A second linkage switching mechanism 10 is provided between the cam follower 8 and the cam follower 8 for appropriately linking or releasing the linkages 6 and 8.

  The low-speed cam 3 is formed in a cam profile that creates a so-called valve stop state by slightly opening and closing one of the intake valves 1 corresponding to low rotation. The medium speed cam 5 is formed in a cam profile that satisfies the valve lift characteristics required from the low rotation to the medium rotation of the internal combustion engine, while the high speed cam 4 is required at a high rotation. The valve lift characteristic and the profile that increases the valve lift amount and the valve opening period compared with the medium speed cam 5 are formed.

  The first rocker arm 6 is formed in a substantially rectangular shape that is long in the front-rear direction when viewed from the plane, and a base end portion 6a is swingably supported by a rocker shaft 11 provided in parallel with the camshaft 2, and has a distal end. The portion 6b is in contact with the stem top portion 1a of the one intake valve 1, and a roller 12a in which the low speed cam 3 is slidably contacted with the notch portion 6c on the tip end portion 6b side is rotatably provided. Further, the first rocker arm 6 is formed with a notch hole for accommodating a first lever member 17 described later on one side of the second rocker arm 7 side.

  The second rocker arm 7 is disposed adjacent to one side surface of the first rocker arm 6, a base end portion 7a is swingably supported by the rocker shaft 11, and a distal end portion 7b is disposed on the other side. A roller 12b that is in contact with the stem top portion 1a of the intake valve 1 and is slidably contacted with the medium speed cam 5 is rotatably provided in a rectangular hole formed at a substantially central position on the front end portion 7b side. .

  The high-speed cam follower 8 is disposed in a rectangular space formed on one side of the second rocker arm 7, and a base end portion 8a is supported on a support shaft 13 supported at opposite ends of the space portion. As shown in FIGS. 9 and 10, the cam follower portion which is supported so as to be swingable and does not have a portion in contact with each intake valve 1, 1 and which is in sliding contact with the high-speed cam 4 on the upper surface. 8c is formed to project in an arc shape. The high-speed cam follower 8 is urged upward by a lost motion spring 14 mounted between the lower surface of the lower portion and the upper surface of the lower wall of the second rocker arm 7 and is integrally provided at the lower portion of the rear end portion. The maximum upward swing position is regulated when the regulated projection 15 abuts on the regulation recess 16 formed on the upper surface of the base end 7 a of the second rocker arm 7.

  As shown in FIGS. 9 and 10, the first linkage switching mechanism 9 includes a first lever member 17 that is swingably accommodated in a cutout hole of the first rocker arm 6, and one side of the second rocker arm 7. A projection 18 integrally projecting in the direction of the notch hole and engaging with the upper end 17a of the first lever member 17 as appropriate, and a lower end 17b of the first lever member 17 linked to the lower end 17b. One hydraulic drive unit 19 and a hydraulic circuit 20 that supplies and discharges hydraulic pressure to and from the first hydraulic drive unit 19 are provided.

  The first lever member 17 is bent in a substantially U shape, and is inserted into a pivot pin 21 having both ends fixed to opposite side walls of the notch hole of the first rocker arm 6 via a substantially central insertion hole 17c. And is swingably supported. Further, the upper surface of the upper end portion 17a can be engaged with the lower surface of the tip end of the projection portion 18 while rotating, and the inner end surface of the lower end portion 17b bent in a substantially arc shape is the first hydraulic drive unit. 19 abuts.

  Further, the first lever member 17 is biased in a direction in which the engagement with the protrusion 18 is released by a first biasing mechanism 22 provided in the upper wall of the first rocker arm 6. The first urging mechanism 22 is provided with a cylindrical sliding hole 22a formed in the upper wall of the first rocker arm 6, and is slidably provided inside the sliding hole 22a. A plunger 22b that is in contact with the upper inner surface of the first lever member 17 and elastically mounted in the sliding hole 22a, the plunger 22b pushes out the inner surface and biases the first lever member 17 in the disengagement direction. And a coil spring 22c.

  As shown in FIG. 11, the second linkage switching mechanism 10 is formed at the lower end of the second lever member 23 at the lower end of the tip 7b of the second rocker arm 7 and the lower end of the cam follower 8c of the high-speed cam follower 8. The second lever member 23 is linked to the concave step portion 24 with which the upper end portion 23a of the second lever member 23 abuts and engages appropriately and the lower end portion 23b of the second lever member 23, and hydraulic pressure is supplied and discharged from the same hydraulic circuit 20. 2 hydraulic drive unit 25.

  The second lever member 23 is swingably supported by a pivot pin 34 whose both ends are fixed to the lower wall of the second rocker arm 7 through a substantially central insertion hole 23c. Further, the upper surface of the upper end portion 23a can be engaged and disengaged while rotating to the lower surface of the stepped portion 24, and the inner end surface of the lower end portion 23b bent in a substantially arc shape is the second hydraulic drive unit 25. Abut.

  The second lever member 23 is urged in a direction in which the engagement with the stepped portion 24 is released by a second urging mechanism 26 provided in the lower wall of the second rocker arm 7. The second urging mechanism 26 is provided with a cylindrical sliding hole 26a formed in the lower wall of the second rocker arm 7, and is slidably provided inside the sliding hole 26a. A plunger 26b that is in contact with a pressing piece 23d that protrudes laterally from the upper side surface of the second lever member 23 and an inner surface of the pressing piece 23d that is elastically mounted in the sliding hole 26a and is pushed through the plunger 26b. A coil spring (not shown) that biases the second lever member 23 in the disengagement direction is configured.

  The first and second hydraulic drive units 19 and 25 include cylinders 19a and 25a formed at lower end portions of the base end portions 6a and 7a of the first and second rocker arms 6 and 7, respectively, and the cylinder 19a. , 25a is provided slidably and the front end surface is formed on the rear end side of each of the operating pistons 19b, 25b, and the operating pistons 19b, 25b abutting against the lower end portions 17b, 23b of the lever members, respectively. The hydraulic chambers 19c and 25c are provided.

  As shown in FIG. 7, the hydraulic circuit 20 is formed in the internal axial direction of the rocker shaft 11 and inside the base end portions 6a and 7a of the rocker arms 6 and 7, and is provided in the hydraulic chambers 19c and 25c. First and second hydraulic passages 27 and 28 that communicate with each other, an oil pump 31 that supplies hydraulic oil in the oil pan 35 to the hydraulic chambers 19c and 25c through the hydraulic passages 27 and 28, and the oil The electromagnetic control valve 33 is provided on the downstream side of the pump 31 and switches between the hydraulic passages 27 and 28 and the drain passage 29 by a control signal from the controller 32.

  As shown in FIGS. 1 to 3, the electromagnetic control valve 33 includes a bottomed cylindrical valve body 36 fixed to the outside of the cylinder head, and an electromagnetic drive unit 37 provided on one end side of the valve body 36. A spool valve 38 accommodated in the valve body 36 so as to be movable (slidable) in the axial direction, and moved in one direction by the driving force of the electromagnetic drive portion 37; and the spool valve 38 is electromagnetically driven. It is mainly comprised from the urging means urged | biased in steps from the opposite direction to the drive force of the part 37. FIG.

  The valve body 36 is formed with a valve hole 39 for accommodating the spool valve 38 inside one end closed, and a supply port 36a opened to the valve hole 39 from the radial direction at a substantially central position of the peripheral wall. It has been drilled. In addition, first and second output ports 36b and 36c that open to the valve hole 39 and communicate with the hydraulic passages 27 and 28, respectively, are formed from both sides of the supply port 36a from the radial direction. In addition, a drain port 36d communicating with the oil pan 35 through the drain passage 29 is formed along the radial direction at a side position of the second output port 36c. Further, in the peripheral wall of the valve body 36, there is a communication passage 36f having one end opened to a drain hole 36e formed in the radial direction in the vicinity of the first output port 36b and the other end opened to the drain port 36d. Is formed.

  The electromagnetic drive unit 37 is a so-called proportional control type, and is a cylindrical electromagnetic coil 40 disposed inside the casing 37 a and is fixed to the outer end of the casing 37 a and is turned off and excited by the electromagnetic coil 40. A substantially covered cylindrical fixed yoke 41, a movable plunger (movable yoke) 42 slidably accommodated in the fixed yoke 41, and fixed to one end of the movable plunger 42, the leading edge of the spool valve The driving shaft 43 is in contact with one end edge of the 36 axial direction. The electromagnetic coil 40 is energized or de-energized from the controller 32, and the energization amount at the time of energization is proportionally increased or decreased.

  The spool valve 38 has three valve bodies that selectively open and close the supply port 36a, the first and second output ports 36b and 36c, and the drain port 36d on the outer peripheral surface of the valve shaft 38a according to the movement position of the spool valve 38. The cylindrical first to third land portions 43 to 45 are integrally formed with a predetermined interval. The valve shaft 38a is integrally provided with a disc-shaped locking portion 46 with which the drive shaft 43 abuts at one end edge on the electromagnetic drive portion 37 side, and at the other end edge is a disc-shaped first. A spring retainer 47 is provided integrally. Further, a small-diameter columnar restricting portion 48 for restricting the maximum rightward movement position of the spool valve 38 in FIG. 1 is provided at the outer end of the first spring retainer 47.

  The biasing means is accommodated in the tip of the valve hole 39 and is elastically mounted between the bottom surface of the valve hole 39 and the first spring retainer 47 so that the spool valve 38 is always directed toward the electromagnetic drive unit 37 (left side in the figure). A first spring member 49 that is biased in the direction) and a first spring member 49 that is accommodated in the rear end portion of the valve hole 39 from the predetermined movement position in the right direction of the spool valve 38 via the second spring retainer 51. And a second spring member 50 that jointly applies a spring biasing force.

  The first and second spring members 49 and 50 are formed by coil springs and are biased in the same direction with respect to the spool valve 38, and the coil diameter of the second spring member 50 is more than the first. Largely formed. The second spring member 50 is elastically mounted between the second spring retainer 51 and the stepped wall 39a of the valve hole 39, and presses the second spring retainer 51 against the front end surface of the casing 37a.

  As shown in FIGS. 1, 4A, and B, the second spring retainer 51 is formed in a cup shape and includes a disc-shaped bottom wall 51a and a cylindrical wall 51b rising from the outer peripheral edge of the bottom wall 51a. An insertion hole 51c into which the tip of the valve shaft 38a of the spool valve 38 is slidably inserted is formed at a substantially central position of the bottom wall 51a, and the radial direction extends from the insertion hole 51c. A notch groove 51d is formed. When the second spring retainer 51 is attached to the valve shaft 38a, the cutout groove 51b is fitted from the outside in the radial direction of the valve shaft 38a so as to be easily fitted into the fitting insertion hole 51c.

  Further, as shown in FIGS. 1 and 4B, the second spring retainer 51 has an axial length L when the spool valve 38 is located in the maximum left direction. And the opposite surface of the locking portion 46 is set so that a gap C having a predetermined width is formed, and when the spool valve 38 moves rightward by a predetermined length, the locking portion The opposing surface of 46 abuts against the inner surface of the bottom wall 51a, and the spring force of the second spring member 50 acts when the spool valve 38 moves further to the right.

  The controller 32 inputs a rotation signal of the internal combustion engine, a cooling water temperature signal, a lubricating oil temperature signal, and a throttle valve opening signal, and controls the electromagnetic coil 40 of the electromagnetic control valve 33 based on these detected values. Output current.

  Therefore, according to this embodiment, the energization from the controller 32 to the electromagnetic control valve 33 is cut off in a predetermined low rotation range from the time of extremely low rotation during idle operation after engine startup. Accordingly, as shown in FIG. 1, the spool valve 38 is configured such that the first land portion 43 and the third land portion 45 block communication between the supply port 36a and the output ports 36b and 36c, and the drain ports 38b and 36c and the drain port. The port 36d is connected. For this reason, the hydraulic oil pumped from the oil pump 31 is blocked from being supplied from the first and second hydraulic passages 27 and 28 to the first and second hydraulic chambers 19c and 25c, and in the second hydraulic chamber 25c. Is returned from the second hydraulic passage 28 to the oil pan 35 through the drain port 36d.

  For this reason, each actuating piston 19b, 25b does not press the lower end portions 17b, 23b of each lever member 17, 23. Accordingly, the first and second rocker arms 6 and 7 swing according to the cam profiles of the low-speed and medium-speed cams 3 and 5, and the high-speed cam follower 8 swings according to the lift of the high-speed cam 4. However, the lever members 17 and 23 are disengaged from the upper end portions 17a and 23a and the corresponding protrusions 18 and step portions 24 by the spring force of the coil springs of the biasing mechanisms 22 and 26, respectively. Since the high-speed cam follower 8 exhibits the lost motion function, the lift transmission of the high-speed cam 4 to the second rocker arm 7 is not performed.

  Therefore, the rocker arms 6 and 7 swing according to the cam profiles of the low-speed cam 3 and the medium-speed cam 5 via the rocker shaft 11, and one intake valve 1 is a minute amount of the first rocker arm 6. The other intake valve 1 opens and closes according to a predetermined valve lift characteristic of the second rocker arm 7 while opening and closing with an extremely low valve lift characteristic by a simple swing stroke. That is, one intake valve 1 is in an inactive state. Therefore, the fuel consumption can be improved in such a driving region. In addition, since one intake valve 1 is operated by a very low valve lift by the first rocker arm 6, it is possible to prevent the occurrence of sticking with the valve seat due to sludge in exhaust gas.

  When the engine shifts from the low rotation range to the middle rotation range, which is a steady operation range, an ON signal is output from the controller 32 to the electromagnetic control valve 33, and the spool valve 38, as shown in FIG. The locking portion 46 abuts against the inner surface of the bottom wall 51 a of the second spring retainer 51 by moving to the right against the spring force of the member 49. In this intermediate movement position, the first land portion 43 continues to block communication between the supply port 36a and the second output port 36c, and the second land portion 44 also continues to communicate between the second output port 36c and the drain port 36d. The third land portion 45 allows the supply port 36a and the first output port 36b to communicate with each other, and simultaneously blocks the communication between the first output port 36b and the drain hole 36b.

  As a result, the hydraulic pressure of the oil pump 31 is supplied from the first hydraulic passage 27 to the first hydraulic chamber 19c to press the first hydraulic piston 19b. For this reason, as shown in FIG. 10, the first lever member 17 rotates against the spring force of the coil spring 22c, and the upper end portion 17a engages and abuts the lower surface of the projection portion 18. The first rocker arm 6 and the second rocker arm 7 are connected together. Therefore, the first rocker arm 6 swings following the swing stroke of the second rocker arm 7 as the roller 12a rises from the low speed cam 3. Therefore, both intake valves 1 and 1 are opened and closed with a middle valve lift characteristic according to the cam profile of the medium speed cam 5. As a result, both sufficient output torque and fuel consumption requirements can be satisfied.

  On the other hand, when the engine shifts to the high speed range, the amount of control current supplied from the controller 32 is increased, the driving force of the electromagnetic drive unit 37 is increased, and the spool valve 38 is moved as shown in FIG. In order to press the second spring retainer 51 to the right via the locking portion 46, the second spring retainer 51 is now moved further to the right against the combined spring force of the first and second spring members 49, 50.

  Thus, the third land portion 45 maintains communication between the supply port 36a and the first output port 36b, while the first land portion 43 allows communication between the supply port 36a and the second output port 36c, and the third land portion. 45 cuts off communication between the second output port 36c and the drain port 36d.

  Therefore, the hydraulic pressure pumped from the oil pump 31 is supplied to the second hydraulic passage 28 in addition to the first hydraulic passage 27, and the hydraulic pressure is supplied to both the hydraulic chambers 19c and 25c, so that the second hydraulic passage 19 is supplied. As the pressure in the hydraulic chamber 25c increases, the second working piston 25b also advances. Accordingly, the second operating piston 25b rotates the second lever member 23 counterclockwise in FIG. 11 against the spring force of the coil spring of the second urging mechanism 26. As a result, the upper end portion 23a of the second lever member 23 is engaged with the step portion 24, and the second rocker arm 7 and the high-speed cam follower 8 are integrally connected.

Therefore, the rocker arms 6 and 7 swing according to the profile of the high-speed cam 4, that is, the rollers 12 a 12 b of the rocker arms 6 and 7 are lifted from the low-speed cam 3 and the medium-speed cam 5 and come into contact with each other. It is avoided and swings following the swing of the high-speed cam follower 8. For this reason, both the intake valves 1 and 1 open and close according to the high valve lift characteristic according to the profile of the high speed cam 4. As a result, the intake charge efficiency is increased and the output torque can be improved.As described above, according to the present embodiment, the engine performance can be sufficiently exhibited by switching the valve lift characteristics according to the engine operating state. Needless to say, the first lever member 17 is accommodated in the cutout hole 11 of the first rocker arm 6 having the smallest lift amount, and the protrusion 18 that contacts and engages with the first lever member 17 is provided in the cutout portion 11. Since it is provided on the side of the second rocker arm 7 on the hole 11 side, the degree of freedom in layout of the first lever member 17 and the protrusion 18 is improved, and the protrusion of the rocker arm is eliminated, so that the entire apparatus can be made compact. I can plan.

  As described above, when the spool valve 38 is initially moved, the electromagnetic control valve 33 moves by a predetermined amount in one direction against the spring force of the first spring member 49 by the proportionally controlled electromagnetic drive unit 37. And since the spring force of the 2nd spring member 50 is added when the latching | locking part 46 contact | abuts to the 2nd spring retainer 51, the whole urging | biasing force increases in steps from this time.

  That is, as shown in FIGS. 5A, 5B, and 6, the spool valve 38 moves according to a proportional energization amount to the electromagnetic drive unit 37, but in the initial energization (I1 region), the first force is generated by this thrust. It moves against only the spring force of the spring member 49. Then, since the urging force of the second spring member 50 acts when the locking portion 46 comes into contact with the second spring retainer 51, as shown in FIG. Although it rises proportionally, the spool valve 38 is held at the intermediate position (M) without moving until a predetermined energization amount (I2) to the electromagnetic drive unit 37 is reached. In other words, at this intermediate position, the spool valve 38 can be held at the intermediate position in a stopped state against the driving force of the electromagnetic drive unit 37 even if it is affected by a disturbance or the like.

  Accordingly, the intermediate movement position of the spool valve 38 can be controlled stably and with high accuracy. As a result, the control accuracy of the valve lift amount of the intake valves 1 and 1 can be improved.

  Thereafter, when the energization amount to the electromagnetic drive unit 37 becomes equal to or greater than a predetermined value (I3), the increased urging force of the first and second spring members 49 and 50 is overcome and the spool valve 38 is further moved to a desired position in one direction. Can be moved to.

  After the spool valve 38 has moved to the maximum rightward position, the spool valve 38 is moved to its leftward position by appropriately reducing the amount of current supplied to the electromagnetic drive unit 37 in response to a change in the engine operating state. Accordingly, the combined force of the urging forces of the first and second spring members 49 and 50 or the single spring force of the first spring member 49 acts selectively.

  In addition, it is not necessary to provide two electromagnetic control valves 33, and the three cams 3, 4, and 5 can be operated and controlled individually, so that the cost can be greatly reduced.

  FIG. 12 shows a second embodiment, in which the first spring member 49 is arranged in parallel in a double state on the inner peripheral side of the second spring member 50 on the electromagnetic drive unit 37 side instead of the front end side of the spool valve 38. It is what.

  That is, a large-diameter disk-shaped first spring retainer 52 is integrally provided on the rear end side of the valve shaft 38 a of the spool valve 38, that is, between the second spring retainer 51 and the second land portion 44. A first spring member 49 is elastically mounted between the one end surface of the first spring retainer 52 and the step portion of the valve hole 39.

  Therefore, when the spool valve 38 moves by a predetermined amount in the right direction in the figure while compressing and deforming the first spring member 49 as the electromagnetic drive unit 37 is energized, the locking portion 46 comes into contact with the second spring retainer 51. From here, the spring force of the second spring member 50 acts on the spool valve 38.

  Therefore, the same operational effects as those of the first embodiment can be obtained. In particular, in this embodiment, the first and second spring members 49 and 50 are arranged in parallel in the inner and outer doubles, so that electromagnetic control is performed. The axial length of the entire valve 33 can be shortened. As a result, the apparatus can be reduced in size and weight.

  FIG. 13 shows a third embodiment, in which the urging means is further increased by one based on the structure of the first embodiment, and is made into three stages.

  That is, a third spring retainer 53 having a large diameter is arranged in parallel on the outer peripheral side of the second spring retainer 51, and a third portion is provided between the outer peripheral portion of the third spring retainer 53 and the step wall 39 a of the valve hole 39. The spring member 54 is elastically mounted. The third spring retainer 53 is formed in a large-diameter cup shape substantially similar to the second spring retainer 51, and a hole through which the valve shaft 38a of the spool valve 38 is loosely inserted is formed in the center. Further, on the inner peripheral surface of the peripheral wall of the third spool retainer 53, as shown in FIG. 13B, a guide that an annular protrusion 51a on one end outer peripheral surface of the second spring retainer 51 is slidably held in the axial direction. The groove 55 is formed short along the axial direction.

  Therefore, when the spool valve 38 moves a predetermined amount in the right direction in the figure by the driving force of the electromagnetic driving portion 37 against the spring force of the first spring member 49, the locking portion 46 contacts the second spring retainer 51. From this point, the spring force of the second spring member 50 starts to act, and the spool valve 38 is once held in this intermediate movement position. Thereafter, when the energization amount to the electromagnetic drive unit 37 is proportionally increased to a predetermined value or more, the spool valve 38 further resists the spring force of the first and second spring members 49 and 50 and further increases to the right by a predetermined amount. When it moves, the annular protrusion 55 abuts against the end edge of the guide groove 55, and the spring force of the third spring member 54 starts to act from here through the third spring retainer 53. For this reason, the spool valve 38 is held at the second intermediate position applied by the spring force of the third spring member 54.

  When the energization amount to the electromagnetic drive unit 37 further increases thereafter, the spool valve 38 moves to the right against the spring force of all the spring members 49, 50, 54, and the land portions 43 to 45 are moved. The ports 36a to 36e are opened / closed.

  As described above, in this embodiment, the spool valve 38 can be stably held at the two intermediate movement positions in the axial direction. Therefore, the ports 36a to 36e can be opened and closed stably and accurately. Is possible.

  FIG. 14 shows a fourth embodiment, in which the positions of the urging means in the first embodiment are reversed.

That is, a disc-shaped first spring retainer 47 is integrally provided at the end of the valve shaft 38 a on the electromagnetic drive portion 37 side, and the spool valve 38 is provided between the first spring retainer 47 and the step wall 39 a of the valve hole 39. A first spring member 49 that urges the lever to the left is mounted. On the other hand, an annular second spring retainer 51 is slidably provided in the axial direction on the inner periphery of the distal end side of the valve hole 39, and a second spring retainer 51 is interposed between the second spring retainer 51 and the bottom surface of the valve hole 39. The spring member 50 is elastically mounted. In addition, an insertion hole 51a through which the restricting portion 48 of the valve shaft 38a of the spool valve 38 can be inserted is formed at the center position of the second spring retainer 51. Further, a flange portion 55 detachably connected to the second spring retainer 51 is integrally provided at the distal end side of the valve shaft 38a, that is, at the base end portion of the regulating portion 48. Therefore, according to this embodiment. For example, when the spool valve 38 moves a predetermined amount in the right direction against the spring force of the first spring member 49 along with the energization of the electromagnetic drive unit 37, the flange portion 55 comes into contact with the second spring retainer 51. From here, the spring force of the second spring member 50 starts to act. Therefore, the spool valve 38 can be stably held at this intermediate position from this point to the predetermined energization amount.

  Therefore, the fourth embodiment can provide the same operation and effect as the first embodiment.

  The present invention is not limited to the configuration of each of the above embodiments, and the variable valve lift mechanism is a two-stage type of large and small lifts, which are respectively provided on the intake valve side and the exhaust valve side, and the electromagnetic control according to the present invention. It is also possible to switch and control both variable valve lift mechanisms using a valve. That is, for example, when both the electromagnetic drive units are not energized, the valve lift is controlled to a small lift on both the intake and exhaust sides without supplying the hydraulic pressure by the electromagnetic control valve. Next, by energizing the electromagnetic drive unit, the spool valve is moved to the right to operate only the variable valve lift mechanism on the intake side from the supply port via the first output port, thereby controlling the intake valve to a large lift. On the other hand, since the supply of hydraulic pressure to the second output port is stopped, the variable valve lift mechanism on the exhaust side does not operate and the exhaust valve maintains a small lift.

  Further, the energization amount to the electromagnetic drive unit 37 is increased and the spool valve is further moved to the right. This time, the second output port is also communicated with the supply port, and the valve lift variable mechanism on the exhaust side is also operated. This makes it possible to perform large lift control on both the intake valve and the exhaust valve.

  As described above, the electromagnetic control valve of the present invention can simultaneously control the variable valve lift mechanisms of both the intake and exhaust valves. Therefore, when the electromagnetic control valves are separately provided on the intake side and the exhaust side, respectively. In comparison, manufacturing costs and assembly costs can be greatly reduced.

  Further, it can be applied not only to the variable valve lift mechanism but also to a variable valve timing mechanism, and also to other devices.

The technical ideas other than the invention described in the claims, as grasped from the embodiment, will be described below.
(A) The actuator is a hydraulic valve drive mechanism according to claim 4, wherein the actuator is a variable valve lift mechanism that variably controls the lift amount of the engine valve of the internal combustion engine in accordance with the engine state.
(B) The hydraulic valve drive mechanism according to (a), wherein the variable valve lift mechanism controls the lift amount of the engine valve in at least two stages.
(C) The variable valve lift mechanism switches and controls the lift amount of the engine valve in at least three stages.

It is a longitudinal section showing an electromagnetic control valve concerning a 1st embodiment of the present invention. It is a longitudinal cross-sectional view of the electromagnetic control valve explaining the effect | action of this Embodiment. It is a longitudinal cross-sectional view of the electromagnetic control valve explaining the effect | action of this Embodiment. A is a perspective view showing a spool valve, a second spring retainer and the like provided in the present embodiment, and B is a perspective view of the second spring retainer. A is a characteristic diagram showing the relationship between the amount of current applied to the electromagnetic drive and the amount of movement of the spool valve in this embodiment, and B is the relationship between the amount of current applied to the electromagnetic drive and the thrust of the electromagnetic drive. FIG. It is a characteristic view which shows the relationship between the spring deformation amount accompanying the electricity supply to the electromagnetic drive part of the 1st, 2nd spring member in this Embodiment, and a spring urging | biasing force. It is a principal part front view of the valve lift variable mechanism of the internal combustion engine to which the electromagnetic control valve concerning this invention was applied. FIG. 8 is a view taken in the direction of arrow X in FIG. 7. It is the sectional view on the AA line of FIG. 7 which shows the effect | action of a valve lift variable mechanism. It is the sectional view on the AA line of the same FIG. 7 which shows the effect | action of the valve lift variable mechanism. FIG. 7 is a cross-sectional view taken along the line 7B-B in FIG. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the electromagnetic control valve of this invention. A is a longitudinal sectional view showing a third embodiment of the electromagnetic control valve of the present invention, and B is an enlarged view of a main part of the present embodiment. It is a longitudinal cross-sectional view which shows 4th Embodiment of the electromagnetic control valve of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Intake valve 2 ... Cam shaft 3 ... Low speed cam 4 ... High speed cam 5 ... Medium speed cam 6 ... 1st rocker arm 7 ... 2nd rocker arm 9 ... 1st linkage switching mechanism 10 ... 2nd linkage switching mechanism 20 ... Hydraulic circuit 27, 28 ... Hydraulic passage 31 ... Oil pump 33 ... Electromagnetic control valve 36 ... Valve body 36a ... Supply port 36b / 36c ... First and second output ports 37 ... Electromagnetic drive unit 38 ... Spool valve 38a ... Valve shaft 43 ˜45... 1st to 3rd land portion 46... Locking portion 47 and 51... First and second spring retainers 49 and 50.

Claims (4)

An electromagnetic drive unit capable of proportionally controlling the driving force in accordance with the energization amount;
A spool valve that selectively opens and closes a plurality of opening holes in accordance with a movement position in the axial direction, and moves in one direction by a driving force of the electromagnetic drive unit;
Urging means for urging the spool valve from a direction opposite to the driving direction by the electromagnetic driving unit to change the movement position of the spool valve;
The electromagnetic control valve according to claim 1, wherein the urging means is formed such that the urging force can be changed stepwise in accordance with a moving position of the spool valve by the driving force of the electromagnetic driving unit. The biasing means is constituted by a plurality of spring members, and the spring force of each spring member acts in a stepwise manner according to a predetermined movement position of the spool valve that has slid according to the energization amount of the electromagnetic drive unit. The electromagnetic control valve according to claim 1, wherein the electromagnetic control valve is formed as described above. Providing a first spring member of the biasing means for constantly biasing the spool valve in the other direction;
A locking portion is fixed to one end portion of the spool valve on the electromagnetic drive portion side,
And, at the one end portion, a spring retainer that is detachable from the locking portion in the axial direction is provided movably,
The second spring member of the urging means is elastically contacted to the end surface of the spring retainer opposite to the locking portion;
When the spool valve moves by a predetermined amount in one direction against the urging force of the first spring member by the driving force of the electromagnetic driving portion, the locking portion abuts against a spring retainer and the second spring The electromagnetic control valve according to claim 1, wherein the biasing force of the member acts in a stepwise manner. A hydraulic pump that discharges hydraulic oil, an electromagnetic control valve that switches a flow path of hydraulic oil pumped from the hydraulic pump to supply and discharge hydraulic pressure to the actuator, and a controller that controls the amount of current supplied to the electromagnetic control valve; A hydraulic drive device comprising:
The electromagnetic control valve is
An electromagnetic drive unit provided on one end side of the valve body and capable of proportionally controlling the drive force in accordance with the energization amount;
A spool valve which is provided in the valve body so as to be movable in the axial direction, and selectively opens and closes a plurality of supply ports, output ports and drain ports according to the movement position, and switches the flow path;
An urging means for urging the spool valve in a direction opposite to the driving force of the electromagnetic driving unit;
The hydraulic drive device according to claim 1, wherein the biasing means is formed such that the biasing force can be changed stepwise in accordance with a moving position of the spool valve by the driving force of the electromagnetic driving unit.

Images