JP2012107677A - Variable valve timing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact electromagnetic actuator to be used for an OCV (oil flow control valve) configured to supply pump oil pressure into a spool.SOLUTION: Pump oil pressure is supplied to first and third whole-circumferential grooves 31, 33 on both sides among three grooves on an outer periphery of a spool 16, and the pressure is discharged from a second whole-circumferential groove 32 in the center. A driving spool oil passage hole 21 for guiding to the third whole-circumferential groove 33 the pump oil pressure guided to the first whole-circumferential groove 31 is provided in the spool 16. Furthermore, a respiratory spool oil passage hole 22 communicating with spaces A, B adjacent to the spool 16, communicating with a drain port 12 via the second whole-circumferential groove 32, and also communicating with an internal space of a cup guide 19, is provided in the spool 16 to allow change in volume of the spaces A, B adjacent to the spool 16 and spaces B, E adjacent to a plunger 18. The internal pressure of the cup guide 19 is reduced to reduce the wall thickness thereof, and attractive magnetic force is improved to achieve a compact electromagnetic actuator 7.

Description

  According to the present invention, the valve opening / closing timing is changed by changing the advance amount of a camshaft (either an intake valve, an exhaust valve, or an intake / exhaust camshaft) driven by an engine (internal combustion engine) using hydraulic pressure. The present invention relates to a variable valve timing device (variable valve timing: hereinafter referred to as VVT).

VVT that varies the valve opening and closing timing using hydraulic pressure is a variable camshaft timing mechanism (variable camshaft timing: below) that varies the amount of camshaft advance by the hydraulic pressure difference between the advance chamber and retard chamber And VCT) and a hydraulic circuit for controlling the hydraulic pressure difference between the advance chamber and the retard chamber.
This hydraulic circuit is equipped with an electromagnetic spool valve (oil flow control valve: hereinafter referred to as OCV) that controls the supply and discharge of oil to the advance chamber and the supply and discharge of oil to the retard chamber. Is controlled by energization by an engine control device (engine control unit: hereinafter referred to as ECU), thereby controlling the hydraulic pressure in the advance chamber and the retard chamber and controlling the opening / closing timing of the valve (for example, Patent Document 1).

The OCV disclosed in Patent Document 1 will be described with reference to FIG. In addition, the following code | symbol attaches | subjects the same code | symbol to the same function thing as [the form for inventing] and [Example] which are mentioned later.
The OCV 4 is a combination of an axial direction of a spool valve 6 that performs oil path switching control and an electromagnetic actuator 7 that drives the spool valve 6. The spool valve 6 is provided with a driving spool internal oil passage hole 21 to which a pump hydraulic pressure pressurized through the pump port 11 is supplied inside the spool 16. The pump hydraulic pressure supplied to the inside of the hole 21 is provided so as to be supplied to the advance chamber or the retard chamber according to the axial position of the spool 16.

When the electromagnetic actuator 7 is operated, it is necessary to change the volumes of the spaces B and E at both ends of the plunger 18. However, as shown in FIG. 4, the electromagnetic actuator 7 is arranged in a state of being exposed to the outside of the engine component Z (cylinder head or the like). For this reason (to prevent oil leakage from the electromagnetic actuator 7 to the outside of the engine), the spaces B and E at both ends of the plunger 18 cannot be communicated with the outside (atmosphere).
Therefore, by arranging the cup guide 19 inside the electromagnetic actuator 7 to partition the inside of the electromagnetic actuator 7 and communicating the spaces B and E at both ends of the plunger 18 with the oil passage hole 21 in the driving spool described above, The volume of the spaces B and E at both ends of the plunger 18 can be changed.

However, in the prior art, the pump hydraulic pressure pressurized through the oil passage hole 21 in the driving spool is applied to the inside of the cup guide 19.
For this reason, the cup guide 19 needs to be a pressure vessel, and the thickness of the cup guide 19 needs to be increased in order to increase the strength. Here, the cup guide 19 slidably supports the plunger 18 on the inner peripheral surface, and is provided with a nonmagnetic material. For this reason, an increase in the thickness of the cup guide 19 causes a decrease in the magnetic attractive force of the plunger 18, and an attempt is made to increase the magnetic force generated by the coil 17 in order to compensate for the decrease in the magnetic attractive force. Will lead to an increase in size.
In other words, the OCV 4 in which the drive spool oil passage hole 21 is provided inside the spool 16 has a problem in that the electromagnetic actuator 7 is increased in size.

Japanese Patent No. 4111135

  The present invention has been made in view of the above problems, and an object of the present invention is to reduce the size of an electromagnetic actuator used in an OCV having an oil passage hole in a spool for driving to which pump hydraulic pressure is supplied inside the spool. There is.

[Means of claim 1]
A breathing port (drain port) that communicates with the space in the oil pan (substantially atmospheric pressure space in the engine) through the oil passage or the like inside the spool in the OCV of claim 1 separately from the oil passage hole in the driving spool. And an oil passage hole in a spool for communication between the cup guide and the inside of the cup guide.
In this way, the inside of the cup guide is kept at a low pressure by communicating the inside of the cup guide with the oil passage hole in the breathing spool and the space in the oil pan (substantially atmospheric pressure space) through the breathing port. Can do.
By keeping the inside of the cup guide at a low pressure, the pressure resistance of the cup guide can be reduced, and the cup guide can be thinly provided.
Since the cup guide is made of a non-magnetic material, the magnetic attractive force of the plunger can be increased by providing the cup guide thinly. As a result, the magnetic force generated by the coil can be reduced, and the electromagnetic actuator can be miniaturized.
That is, even with an OCV in which an oil passage hole in the spool for driving is provided inside the spool, the electromagnetic actuator can be downsized.

[Means of claim 2]
The drain port of claim 2 also serves as a breathing port, and the oil passage hole in the breathing spool is always in communication with the drain port.

[Means of claim 3]
The drive spool oil passage hole and the breathing spool oil passage hole of the third aspect are both formed to extend in the axial direction from one end side of the spool. Then, one end side of the oil passage hole in the driving spool is closed by the mech lid, and the oil passage hole in the driving spool and the oil passage hole in the breathing spool are separated.
In this way, two holes (driving spool oil passage hole and breathing spool oil passage hole) are opened from one end of the spool, and the end of one hole (the end of the driving spool oil passage hole). Part) is closed with a mechlet lid, and an independent oil passage hole in the driving spool and an oil passage hole in the breathing spool can be provided inside the spool.

[Means of claim 4]
In the outer periphery of the spool according to the fourth aspect, first, second, and third circumferential grooves independent in the axial direction are provided.
In the retarded state (the state in which the camshaft is driven to the retarded side), the pump port and the retarded port communicate with each other through the first circumferential groove and advance with the drain port through the second circumferential groove. The corner port communicates.
Further, in the holding state (the state in which the advance amount of the camshaft is held), the retard port is closed by the outer peripheral wall surface of the spool between the first and second circumferential grooves, and the second whole circumference is closed. The advance port is closed by the outer peripheral wall surface of the spool between the groove and the third circumferential groove.
Further, in the advanced angle state (the state in which the camshaft is advanced to the advanced angle side), the pump port and the advanced port communicate with each other through the third circumferential groove, and the drain port and the slow port communicate with the drain port through the second circumferential groove. The corner port communicates.

[Means of claim 5]
In the VVT according to the fifth aspect, of the first, second, and third circumferential grooves, the first and third circumferential grooves provided on both sides in the axial direction are always in communication with the oil passage hole in the driving spool. Of the first, second, and third circumferential grooves, the second circumferential groove provided at the center in the axial direction does not always communicate with the oil passage hole in the driving spool but always communicates with the drain port. .

[Means of claim 6]
The oil passage hole in the spool for breathing according to claim 6 is a space formed at both ends of the spool, a space in the shaft that communicates the inside of the shaft that transmits the driving force of the plunger to the spool in the axial direction, and the inside of the plunger in the axial direction. It always communicates with the space in the plunger that communicates with.

It is sectional drawing which follows the axial direction of OCV (Example). It is operation | movement explanatory drawing of OCV (Example). It is the schematic of VVT. It is sectional drawing which follows the axial direction of OCV (conventional example).

[Description of Embodiments] [Mode for carrying out the invention] will be described with reference to the drawings.
The VVT includes a VCT 3 that changes the amount of advance of the camshaft by the hydraulic pressure difference between the advance chamber 1 and the retard chamber 2, and a hydraulic circuit 5 that has an OCV 4 that controls the hydraulic pressure of the advance chamber 1 and the retard chamber 2. Is provided.
The OCV 4 includes a spool valve 6 that switches an oil passage and an electromagnetic actuator 7 that drives the spool valve 6.

  The spool valve 6 includes a pump port 11 to which pump hydraulic pressure pressurized by the oil pump X is supplied, a drain port 12 that communicates with the internal space of the engine oil pan Y, an advance port 13 that communicates with the advance chamber 1, and a retard angle. A sleeve 15 having a retarding port 14 communicating with the chamber 2 and a spool 16 that is slidably supported in the axial direction inside the sleeve 15 and adjusts the communication state of each port.

  The electromagnetic actuator 7 is coupled to the end of the spool valve 6 (specifically, the end of the sleeve 15), and is driven by a coil 17 that generates a magnetic force when energized, and a magnetic force generated by the coil 17. The plunger 18 is integrally displaced with the spool 16 and has a cup guide 19 that partitions the inside of the electromagnetic actuator 7 and supports the plunger 18 slidably.

Inside the spool 16, an oil passage hole 21 in the spool for driving the pump hydraulic pressure supplied from the pump port 11 to at least one of the advance port 13 or the retard port 14, and a drain port 12 (respiratory port) One example) and an oil passage hole 22 in the spool for communicating with the internal space of the cup guide 19 are provided.
1 and 2 show an example in which the breathing port leading to the oil passage hole 22 in the breathing spool is provided in common with the drain port 12, but the breathing port is provided separately from the drain port 12. May be.

Thus, since the inside of the cup guide 19 communicates with the internal space (substantially atmospheric pressure space) of the oil pan Y via the oil passage hole 22 in the spool for respiration and the drain port 12 (breathing port), the cup guide The pressure resistance of 19 can be reduced, and the cup guide 19 made of a non-magnetic material can be thinly provided.
By providing the cup guide 19 made of a non-magnetic material thinly, the magnetic attractive force of the plunger 18 can be increased, and the electromagnetic actuator 7 can be downsized.

Hereinafter, a specific example (example) to which the present invention is applied will be described with reference to the drawings. The following examples are specific examples, and it goes without saying that the present invention is not limited to the examples. In the following embodiments, the same reference numerals as those in the above-mentioned [Mode for Carrying Out the Invention] denote the same functional objects.
In the following description, the left side of FIG. 1 is referred to as “front”, and the right side of FIG. 1 is referred to as “rear”, but this is before and after the description of the embodiment, and is related to the actual mounting direction. There is no limitation.

(Specific Configuration of Example 1)
The VVT is mounted on a vehicle running engine and is attached to a camshaft (either an intake valve, an exhaust valve, or an intake / exhaust combined camshaft) to continuously adjust the amount of advance of the camshaft. It is composed of a VCT 3 that can continuously vary the valve opening and closing timing by varying it, a hydraulic circuit 5 that uses an OCV 4 that hydraulically controls the operation of the VCT 3, and an ECU 23 that electrically controls the OCV 4.

  The VCT 3 includes a shoe housing 24 that is driven to rotate in synchronization with the crankshaft of the engine, and a vane rotor 25 that is provided so as to be rotatable relative to the shoe housing 24 and rotates integrally with the camshaft. The vane rotor 25 is driven to rotate relative to the shoe housing 24 by a hydraulic actuator configured in the shoe housing 24 to change the camshaft to the advance side or the retard side.

The shoe housing 24 is coupled to a sprocket that is rotationally driven by a crankshaft of an engine via a timing belt, a timing chain, or the like by a bolt or the like, and rotates integrally with the sprocket. Inside the shoe housing 24, as shown in FIG. 3, a plurality of substantially fan-shaped recesses 24a (three in this embodiment) are formed. In addition, the shoe housing 24 rotates clockwise in FIG. 3, and this rotation direction is an advance angle direction.
On the other hand, the vane rotor 25 is positioned at the end of the camshaft by a positioning pin or the like and fixed to the end of the camshaft by a bolt or the like, and rotates integrally with the camshaft.

The vane rotor 25 includes a vane 25 a that divides the recess 24 a of the shoe housing 24 into an advance chamber 1 and a retard chamber 2, and the vane rotor 25 is provided to be rotatable within a predetermined angle with respect to the shoe housing 24. It has been.
The advance chamber 1 is a hydraulic chamber for driving the vane 25a to the advance side by hydraulic pressure, and is formed in the recess 24a on the counter-rotation direction side of the vane 25a. Reference numeral 2 denotes a hydraulic chamber for driving the vane 25a to the retard side by hydraulic pressure. The liquid tightness of the advance chamber 1 and the retard chamber 2 is maintained by the seal member 26 and the like.

  The hydraulic circuit 5 supplies and discharges oil in the advance chamber 1 and the retard chamber 2, generates a hydraulic pressure difference between the advance chamber 1 and the retard chamber 2, and rotates the vane rotor 25 relative to the shoe housing 24. For this purpose, a pump hydraulic pressure pumped from an oil pump X driven by a crankshaft or the like is metered into one of the advance chamber 1 or the retard chamber 2, and the advance chamber 1 or the retard chamber 2 is supplied. An OCV 4 capable of metering and discharging the hydraulic pressure is provided.

  The OCV 4 is an electromagnetic spool valve in which an electromagnetic actuator 7 is coupled to the rear end of the spool valve 6. As shown in FIG. 1, the OCV mounting hole 27 in which the spool valve 6 is formed in an engine part Z (cylinder head or the like). The electromagnetic actuator 7 is fixedly arranged outside the engine component Z while being inserted and arranged inside (a hole whose inner peripheral surface has a cylindrical shape).

  The spool valve 6 is an oil passage switching valve that is inserted into the OCV mounting hole 27 and is disposed in the sleeve 15 that is inserted into the OCV mounting hole 27 in the engine component Z. A spool 16 (valve element) having a substantially rod shape and a return spring 28 for urging the spool 16 rearward are provided.

The sleeve 15 has a substantially cylindrical shape, and an outer peripheral surface thereof is inserted into the OCV mounting hole 27 through a fine clearance. Further, the inner peripheral surface of the sleeve 15 supports the spool 16 so as to be slidable in the axial direction. Further, a plurality of input / output ports are formed in the radial direction of the sleeve 15.
Specifically, in the radial direction of the sleeve 15, a pump port 11 that communicates with the oil discharge port of the oil pump X, a drain port 12 that returns oil into the oil pan Y, an advance port 13 that communicates with the advance chamber 1, a slow port. A retarding port 14 communicating with the corner chamber 2 is formed.

More specifically, the OCV mounting hole 27 is provided so that pump hydraulic pressure is supplied from the engine oil pump X via a pump oil passage Z1 (reference numeral, see FIG. 3).
The front end of the sleeve 15 is provided with a small diameter so that the pump hydraulic pressure supplied to the inside of the OCV mounting hole 27 is guided to the pump port 11.

On the other hand, the engine component Z into which the spool valve 6 is inserted includes an advance oil passage Z2 that leads to the advance chamber 1 of the VCT 3, a retard oil passage Z3 that leads to the retard chamber 2 of the VCT 3, and the interior of the engine oil pan Y. A drain oil passage Z4 leading to the space is formed.
Then, by inserting the spool valve 6 into the OCV mounting hole 27 and fastening the electromagnetic actuator 7 to the engine component Z, the retard port 14 communicates with the retard chamber 2 via the retard oil passage Z3, The advance port 13 communicates with the advance chamber 1 through the advance oil passage Z2, and the drain port 12 communicates with the internal space of the oil pan Y through the drain oil passage Z4.

The spool 16 has a substantially cylindrical shape, and its outer peripheral surface is inserted and arranged with a fine clearance with respect to the inner peripheral surface of the sleeve 15. An angle state (a state in which the camshaft is driven to the retard side), a holding state (a state in which the advance amount of the camshaft is held), and an advance state (a state in which the camshaft is driven to the advance side) are achieved.
As means for achieving each state, first, second, and third circumferential grooves 31, 32, 33 that are independent from the front toward the rear are provided on the outer periphery of the spool 16. The first, second, and third circumferential grooves 31, 32, and 33 are grooves formed over the entire circumference, and are formed on the outer circumferential surface of the spool 16 so as to be separated in the axial direction.

The first circumferential groove 31 is always in communication with the pump port 11 and is provided so as to communicate with the retard port 14 when the spool 16 moves rearward.
The second circumferential groove 32 is always in communication with the drain port 12, communicates with the retard port 14 when the spool 16 moves forward, and with the advance port 13 when the spool 16 moves rearward. It is provided to communicate.
The third circumferential groove 33 is always in communication with the pump port 11 via a drive spool oil passage hole 21 formed in the spool 16, and an advance port when the spool 16 moves forward. 13 is provided so as to communicate with 13.

The outer circumferential wall surface of the spool 16 between the first circumferential groove 31 and the second circumferential groove 32 has a retarded chamber closing portion 34 (land portion) capable of closing the retarding port 14 according to the axial position of the spool 16. ).
The outer circumferential wall surface of the spool 16 between the second circumferential groove 32 and the third circumferential groove 33 has an advance chamber closing portion 35 (land portion) that can close the advance port 13 according to the axial position of the spool 16. ).

In the spool 16, there are provided independent drive spool oil passage holes 21 and breathing spool oil passage holes 22 extending in the axial direction.
The drive spool oil passage hole 21 and the breathing spool oil passage hole 22 are both bottomed drill holes (drill holes not penetrating in the axial direction) formed from the front end to the vicinity of the rear end of the spool 16. The spool 16 extends from the front end in the axial direction.
Then, the front end of the drive spool oil passage hole 21 is closed by the meckle lid 36, so that the drive spool oil passage hole 21 and the breathing spool oil passage hole 22 are separated in the spool 16. ing.
As described above, the mecha lid 36 closes the oil passage hole 21 in the driving spool, so that the pump hydraulic pressure is not applied to the spring chamber 37 at the front end of the spool 16. As a result, a problem that the pump hydraulic pressure is applied to the front end surface of the spool 16 (a problem that the pump hydraulic pressure urges the spool 16 rearward) can be avoided.

The oil passage hole 21 in the driving spool is an oil passage for guiding the pump hydraulic pressure supplied from the pump port 11 to the advance chamber 1 through the inside of the spool 16. The spool 16 has an internal / external communication hole 41 for communicating the first circumferential groove 31 and the driving spool internal oil passage hole 21, and an internal / external communication hole for communicating the third full circumferential groove 33 and the driving spool internal oil passage hole 21. 42 is provided.
Thereby, the pump hydraulic pressure supplied via the pump port 11 is always supplied to the first circumferential groove 31 and is always supplied to the third circumferential groove 33 via the oil passage hole 21 in the driving spool. The pump hydraulic pressure can be supplied to the advance port 13 according to the slide position of the spool 16.

On the other hand, the breathing spool internal oil passage hole 22 includes a drain port 12 (a port also serving as a breathing port) that communicates with the internal space of the oil pan Y through the drain oil passage Z4 and the spaces A and B before and after the spool 16. It is an oil passage that always communicates.
Specifically, the front end of the breathing spool oil passage hole 22 communicates with a spring chamber 37 in which the return spring 28 is disposed. A part of the rear end of the spool 16 is provided with a small diameter.
The spool 16 is provided with an internal / external communication hole 43 that allows the small diameter portion and the breathing spool internal oil passage hole 22 to communicate with each other. Further, the spool 16 is provided with an internal / external communication hole 44 that allows the second entire circumferential groove 32 and the breathing spool internal oil passage hole 22 to communicate with each other.

  Accordingly, in addition to the configuration in which the second entire circumferential groove 32 is always in communication with the drain port 12, the spaces A and B before and after the spool 16 are always in communication with the drain port 12 through the oil passage hole 22 in the spool for breathing. Configuration has been achieved.

That is, the spool valve 6 of this embodiment is as described in claim 5,
Of the first, second, and third circumferential grooves 31, 32, 33, the first and third circumferential grooves 31, 33 provided on both sides in the axial direction are always connected to the oil passage hole 21 in the driving spool. Communication,
Of the first, second and third circumferential grooves 31, 32, 33, the second circumferential groove 32 provided in the center in the axial direction does not always communicate with the oil passage hole 21 in the driving spool. The drain port 12 is always in communication.

  The return spring 28 is a compression coil spring that urges the spool 16 rearward. The sleeve 15 includes a closing wall that closes the front end, and a spring chamber 37 is formed between the closing wall and the front end of the spool 16. The return spring 28 is disposed in the spring chamber 37 and is assembled in a state of being compressed in the axial direction between the blocking wall of the sleeve 15 and the spool 16.

The electromagnetic actuator 7 includes a coil 17, a plunger 18, a cup guide 19, a magnetic suction stator 51, a magnetic delivery stator 52, a yoke 53, a stay 54 and a connector 55.
The coil 17 is a magnetic force generating means for generating a magnetic force for magnetically attracting the plunger 18 when energized, and is obtained by winding a large number of conductive wires (such as enameled wires) coated with insulation around a resin bobbin. .

  The plunger 18 is a cylindrical body formed of a magnetic metal (for example, iron: a ferromagnetic material constituting a magnetic circuit) that drives the spool 16 forward by overcoming the urging force of the return spring 28 by the magnetic force generated by the coil 17. And supported on the inner peripheral surface of the cup guide 19 so as to be slidable in the axial direction.

The magnetic attraction stator 51 magnetically attracts the plunger 18 forward, and a disk part 51 a disposed between the sleeve 15 and the coil 17 and the magnetic flux of the disk part 51 a to the vicinity of the plunger 18. A magnetic metal (for example, iron: a ferromagnetic material constituting a magnetic circuit) composed of a cylindrical portion 51b that leads, and a magnetic attraction gap (main gap) is formed between the plunger 18 and the cylindrical portion 51b in the axial direction. It is formed.
The cylindrical part 51b is provided so that it can cross | intersect an axial direction, when the plunger 18 moves ahead. A taper is formed at the end of the cylindrical portion 51b, and the taper is provided so that the magnetic attractive force does not change with respect to the stroke amount of the plunger 18.

  The magnetic delivery stator 52 delivers the magnetism in the radial direction to the periphery of the plunger 18 via the cup guide 19, covers the outer periphery of the plunger 18 via the cup guide 19, and is inserted into the inner circumference of the coil bobbin. And a magnetic metal (for example, iron: a strong magnetic force that constitutes a magnetic circuit) formed of a cylindrical portion 52a and a flange portion 52b that is formed from the cylindrical portion 52a toward the outer diameter direction and is magnetically coupled to the yoke 53 at the outer peripheral edge. Magnetic material), and a magnetic flux delivery gap (side gap) is formed between the cylindrical portion 52a and the plunger 18 in the radial direction.

  The yoke 53 is a cylindrical magnetic metal (eg, iron: a ferromagnetic material constituting a magnetic circuit) that covers the periphery of the coil 17, and the sleeve 15 and the sleeve 15 are caulked with a claw formed at the front end. Combined.

The cup guide 19 is a means for partitioning and separating a portion where the oil is guided inside the electromagnetic actuator 7 so that the oil inside the electromagnetic actuator 7 does not leak to the outside, and is a non-magnetic material having a cylindrical cup shape ( For example, stainless steel).
A flange portion extending in the radial direction is provided at the front end of the cup guide 19, and this flange portion is provided with the sleeve 15 (specifically, an O-ring 56 disposed at the rear end of the sleeve 15), the magnetic suction stator 51, and the like. The inner and outer seals of the cup guide 19 are formed.
The O-ring 57 disposed on the outer periphery of the rear portion of the sleeve 15 is for preventing oil from leaking from the OCV mounting hole 27.

The stay 54 is a means for coupling the OCV 4 to the engine component Z, and is fixed between the step portion formed at the front end of the yoke 53 and the magnetic attraction stator 51. The stay 54 may be coupled to the electromagnetic actuator 7 by other techniques such as welding to the yoke 53.
Then, as described above, the spool valve 6 is inserted into the valve OCV mounting hole 27 and the stay 54 of the electromagnetic actuator 7 is fastened to the engine part Z, whereby the OCV 4 is assembled to the engine.

  The connector 55 is a coupling means formed by a part of a secondary molding resin 58 for resin-molding the coil 17 and the like, and connector terminals 55a respectively connected to the conductive wire end portions of the coil 17 are disposed therein. ing. The connector terminal 55a is resin-molded in the secondary molding resin 58 with the rear end exposed in the connector 55 and the front end inserted into the coil bobbin.

The OCV 4 is provided between the spool 16 and the plunger 18 with a shaft 61 that transmits the driving force of the plunger 18 to the spool 16 and transmits the urging force of the return spring 28 applied to the spool 16 to the plunger 18. .
The shaft 61 shown in this embodiment is a hollow part obtained by processing a non-magnetic metal plate (such as a stainless steel plate) into a cup shape, and a shaft inner space C is formed therein.

  A space B around the shaft 61 is a space B at the rear end of the spool 16 and a space B at the front end of the plunger 18, and is always in communication with the drain port 12 through the oil passage hole 22 in the spool for breathing. Therefore, the space B around the shaft 61 (the space B between the spool 16 and the plunger 18) is provided so that the volume can be varied.

On the other hand, the shaft inner space C communicates with the plunger inner space D formed at the axial center of the plunger 18 through the cup opening at the rear end of the shaft 61.
The shaft inner space C communicates with a space B around the shaft 61 (a space B between the spool 16 and the plunger 18) via a plurality of inner and outer communication holes 62 communicating between the inside and the outside of the shaft 61.
With this configuration, the space E at the rear end of the plunger 18 includes the plunger inner space D, the shaft inner space C, the space B around the shaft 61 (the space B between the spool 16 and the plunger 18), and the breathing spool oil passage. The space E at the rear end of the plunger 18 is provided so as to be capable of changing the volume, and is always in communication with the drain port 12 through the hole 22.

That is, the oil passage hole 22 in the spool for this embodiment is always in communication with the spaces A and B before and after the spool 16, the shaft space C and the plunger space D as described in claim 6. It is.
The space B around the shaft 61 (the space B between the spool 16 and the plunger 18) is divided into front and rear portions by a magnetic attraction assisting part 63 described later, but the front and rear portions of the space B are formed before and after the shaft 61. The plurality of inner and outer communication holes 62 communicate with each other through the shaft inner space C, and also communicate with each other through a through hole formed at the center of a magnetic attraction auxiliary component 63 described later. That is, the front and back of the space B are connected, and the oil can be easily moved.

In the OCV 4 of this embodiment, a magnetic attraction auxiliary component 63 for increasing the magnetic attraction force of the plunger 18 is disposed between the spool 16 and the plunger 18.
The magnetic attraction assisting part 63 is obtained by processing, for example, a magnetic metal plate (for example, iron: a ferromagnetic material constituting a magnetic circuit) into a cup shape, and a step and a cup formed at the rear end of the sleeve 15. It is sandwiched and fixed between the guide 19.
An axial through hole for inserting the shaft 61 is formed at the center of the magnetic attraction auxiliary component 63, and oil can move in the axial direction between the magnetic attraction auxiliary component 63 and the shaft 61. Clear clearance (gap) is formed.

The ECU 23 obtains the camshaft advance amount (advance angle phase) according to the operating state of the engine, and controls the energization of the coil 17 so as to obtain the obtained advance angle amount to obtain the camshaft advance amount in the VCT 3. A program for variable control is provided.
The ECU 23 controls the amount of current supplied to the coil 17 by duty ratio control. By controlling the amount of current supplied to the coil 17, the axial position of the spool 16 is linearly slid to control the engine operating state. The hydraulic pressure corresponding to the pressure is generated in the advance chamber 1 and the retard chamber 2 to variably control the advance amount of the camshaft.

(Specific operation of the embodiment)
Next, the operation of the embodiment will be described with reference to the drawings. In FIG. 2, a solid line arrow α indicates a pump hydraulic pressure supply path (communication path leading to the pump port 11), and a one-dot chain line arrow β indicates a drain hydraulic pressure drainage path (communication path leading to the drain port 12). The broken line arrow γ indicates a respiratory path (communication path leading to the drain port 12).

When the ECU 23 retards the camshaft according to the driving state of the vehicle (when the retarded state is achieved), the ECU 23 decreases the amount of current supplied to the coil 17. Then, the magnetic force generated by the coil 17 is reduced, and the spool 16 moves rearward together with the plunger 18 as shown in FIG.
As a result, the pump port 11 and the retard port 14 communicate with each other via the first circumferential groove 31 to increase the hydraulic pressure in the retard chamber 2, and the drain port 12 and the advance port via the second circumferential groove 32. 13 communicates and the hydraulic pressure in the advance chamber 1 decreases.
As a result, the hydraulic pressure in the retard chamber 2 increases, and conversely, the hydraulic pressure in the advance chamber 1 decreases, and the vane rotor 25 is displaced relative to the shoe housing 24 toward the retard side, and the camshaft advance angle is increased. The amount is displaced to the retard side.
In this retarded state, the spaces A and B before and after the spool 16 and the spaces B and E before and after the plunger 18 are always in communication with the drain port 12 via the oil passage hole 22 in the spool for respiration. It is possible to slide the spool 16 and the plunger 18 in the axial direction.

When the ECU 23 holds the amount of advance of the camshaft according to the driving state of the vehicle (when the holding state is achieved), the ECU 23 controls the amount of current supplied to the coil 17 as shown in FIG. As described above, the outer peripheral wall surface (retarding chamber closing portion 34) of the spool 16 between the first entire circumferential groove 31 and the second entire circumferential groove 32 closes the retardation port 14, and the second entire circumferential groove 32 and the third circumferential groove 32. The spool 16 is slid to a position where the outer peripheral wall surface (advance angle chamber closing portion 35) of the spool 16 between the entire circumferential grooves 33 closes the advance port 13.
In this way, the advance port 13 and the retard port 14 are closed, whereby the hydraulic pressure in the advance chamber 1 and the hydraulic pressure in the retard chamber 2 are kept constant, and the advance amount of the camshaft is maintained.
Even in this holding state, the spaces A and B before and after the spool 16 and the spaces B and E before and after the plunger 18 are always in communication with the drain port 12 through the oil passage hole 22 in the spool for respiration. This is possible, and the sliding displacement of the spool 16 and the plunger 18 in the axial direction is possible.

When the ECU 23 advances the camshaft according to the driving state of the vehicle (when the advancement state is achieved), the ECU 23 increases the amount of current supplied to the coil 17. Then, the magnetic force generated by the coil 17 increases, and the spool 16 moves forward together with the plunger 18 as shown in FIG.
As a result, the pump port 11 and the advance port 13 communicate with each other through the third circumferential groove 33 to increase the hydraulic pressure in the advance chamber 1, and the drain port 12 and the retard port through the second circumferential groove 32. 14 communicates and the hydraulic pressure in the retard chamber 2 decreases.
As a result, the hydraulic pressure in the advance chamber 1 increases, and conversely, the hydraulic pressure in the retard chamber 2 decreases, and the vane rotor 25 is displaced relative to the shoe housing 24 toward the advance side. The amount is displaced to the advance side.
Even in this advanced state, the spaces A and B before and after the spool 16 and the spaces B and E before and after the plunger 18 are always in communication with the drain port 12 via the oil passage hole 22 in the spool for respiration. It is possible to slide the spool 16 and the plunger 18 in the axial direction.

(Effect of Example)
The OCV 4 in this embodiment is provided with a breathing spool oil passage hole 22 in the spool 16 in addition to the drive spool oil passage hole 21 to which pump hydraulic pressure is supplied. The breathing spool internal oil passage hole 22 is an oil passage that communicates the drain port 12 communicating with the internal space (substantially atmospheric pressure space) of the oil pan Y and the inside of the cup guide 19. The inside can be kept at a low pressure.
Thus, since the inside of the cup guide 19 can be kept at a low pressure, the pressure resistance of the cup guide 19 can be reduced, and the cup guide 19 can be made thin.
Since the cup guide 19 is made of a non-magnetic material, the magnetic attractive force of the plunger 18 can be increased by providing the cup guide 19 thinly. As a result, the magnetic force generated by the coil 17 can be reduced, the electromagnetic actuator 7 can be reduced in size, and the vehicle mountability of the OCV 4 can be improved.

The configuration of the electromagnetic actuator 7 shown in the above embodiment is a specific example, and the electromagnetic actuator 7 having another configuration may be used as appropriate.
Specifically, in another form, the magnetic delivery stator 52 and the yoke 53 may be provided integrally. The magnetic attraction stator 51 may be disposed inside the cup guide 19. An oil passage communicating in the axial direction may be provided outside the shaft 61 using a solid shaft 61 instead of the hollow shaft 61. A breathing groove may be formed not on the inside of the plunger 18 but on the outer periphery of the plunger 18.

The configuration of the VCT 3 shown in the above embodiment is a specific example, and a VCT 3 having another configuration may be used as appropriate.
Specifically, in another form, the number of the recesses 24a and the vanes 25a may be changed. Contrary to the above embodiment, the vane rotor 25 may be rotated synchronously with the crankshaft, and the shoe housing 24 may be rotated integrally with the camshaft.

1 Leading angle chamber 2 Slowing angle chamber 3 VCT (variable camshaft timing mechanism)
4 OCV
6 Spool valve 7 Electromagnetic actuator 11 Pump port 12 Drain port (breathing port)
13 Lead angle port 14 Delay port 15 Sleeve 16 Spool 17 Coil 18 Plunger 19 Cup guide 21 Oil passage hole 22 in the spool for driving 22 Oil passage hole 31 in the spool for breathing 31 First circumferential groove 32 Second circumferential groove 33 Third Full-circumferential groove 34 retarded angle chamber blocking portion (the outer peripheral wall surface of the spool between the first and second peripheral grooves)
35 Advance angle chamber closing part (outer peripheral wall surface of spool between second circumferential groove and third circumferential groove)
36 Mechla lid A Space formed at the front end of the spool B Space formed at the rear end of the spool C Shaft inner space D Plunger inner space X Oil pump Y Oil pan Z Engine parts

Claims (6)

A variable camshaft timing mechanism (3) for varying the amount of advancement of the camshaft by the hydraulic pressure difference between the advance chamber (1) and the retard chamber (2);
A pump port (11) to which pressurized hydraulic pressure is supplied, a drain port (12) communicating with the internal space of the oil pan (Y), an advance port (13) communicating with the advance chamber (1), and the retard angle A spool (15) having a retarding port (14) communicating with the chamber (2) and supported in a slidable manner in the axial direction inside the sleeve (15) to adjust the communication state of each port ( 16) a spool valve (6) comprising:
A coil (17) that generates a magnetic force when energized, a plunger (18) that is driven by the magnetic force generated by the coil (17) and is displaced integrally with the spool (16), and the plunger (18) is slid on the inner peripheral surface. An electromagnetic actuator (7) having a cup guide (19) made of a non-magnetic material that movably supports and partitions the inner and outer spaces, and is coupled to the end of the spool valve (6);
In a variable valve timing device comprising:
In the spool (16),
Separately from the drive spool oil passage hole (21) for guiding the pump hydraulic pressure supplied from the pump port (11) to at least one of the advance port (13) or the retard port (14),
A variable valve characterized in that a breathing spool oil passage hole (22) is provided to connect the breathing port (12) communicating with the internal space of the oil pan (Y) and the internal space of the cup guide (19). Timing device. The variable valve timing device according to claim 1,
The drain port (12) serves also as the breathing port, and the oil passage hole (22) in the spool for breathing and the drain port (12) are always in communication with each other. The variable valve timing device according to claim 1 or 2,
The drive spool internal oil passage hole (21) and the breathing spool internal oil passage hole (22) provided in the spool (16) both extend in the axial direction from one end side of the spool (16). Formed,
One end side of the oil passage hole (21) in the driving spool is closed by a cover lid (36), and the oil passage hole (21) in the driving spool and the oil passage hole (22) in the breathing spool A variable valve timing device characterized in that is separated. In the variable valve timing device according to any one of claims 1 to 3,
The outer periphery of the spool (16) is provided with first, second and third circumferential grooves (31, 32, 33) independent in the axial direction,
In the retarded state in which the camshaft is retarded by the spool valve (6), the pump port (11) and the retard port (14) communicate with each other via the first circumferential groove (31). The drain port (12) and the advance port (13) communicate with each other through the second circumferential groove (32),
In the holding state in which the advance amount of the camshaft is held by the spool valve (6), the spool (16) is interposed between the first circumferential groove (31) and the second circumferential groove (32). The retard port (14) is closed by an outer peripheral wall surface, and the advance angle is increased by the outer peripheral wall surface of the spool (16) between the second entire circumferential groove (32) and the third entire circumferential groove (33). Close the port (13),
In the advance state in which the camshaft is advanced by the spool valve (6), the pump port (11) and the advance port (13) communicate with each other via the third circumferential groove (33). The variable valve timing device, wherein the drain port (12) and the retard port (14) communicate with each other through the second circumferential groove (32). The variable valve timing device according to claim 4,
Of the first, second, and third circumferential grooves (31, 32, 33), the first and third circumferential grooves (31, 33) provided on both sides in the axial direction are formed in the drive spool. Always communicate with the oil passage hole (21),
Of the first, second and third circumferential grooves (31, 32, 33), the second circumferential groove (32) provided at the center in the axial direction is always in communication with the drain port (12). A variable valve timing device characterized by that. In the variable valve timing device according to any one of claims 1 to 5,
The breathing spool internal oil passage hole (22) is a space (A, B) formed at both ends of the spool (16), and a shaft for transmitting the driving force of the plunger (18) to the spool (16). 61) A variable valve timing device that is always in communication with a shaft inner space (C) that communicates in the axial direction with the interior of 61) and a plunger inner space (D) that communicates with the interior of the plunger (18) in the axial direction. .

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