JPH11280423A - Valve timing variable device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve assembly and maintenance properties. SOLUTION: A planet gear mechanism 10 is interposed between a cam pulley 2 and a can shaft 1, and the sun gear 11 of the mechanism 10 is provided on a slide member 44 movable along a shaft body 42 by driving an electric motor 30, to convert the axially directional movement of the slide member 44 into rotation via the gear 11, thereby transmitting the rotation to the mechanism 10. The rotation phase of the cam shaft 1 is changed by moving the slide member 74 by the motor 30 while transmitting the rotation of a crank shaft to the cam shaft 1 via the mechanism 10. The motor 30, the shaft body 42, and the slide member 44 are integrally fitted to a casing 35. The motor 30, etc., integral with the casing 35 are made detachable to an engine main body by making the casing 35 detachable to the engine main body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable valve timing device incorporated in a valve operating mechanism of an engine and used for controlling valve timing.

[0002]

2. Description of the Related Art As an example of this type of variable valve timing device, a device as disclosed in Japanese Patent Application Laid-Open No. 4-23212 has been known.

In this device, a planetary gear mechanism comprising a sun gear, a planetary gear supported by a planetary carrier and a ring gear is provided between a camshaft and a cam pulley, and a cam pulley is connected to the ring gear, and the planetary carrier is driven by a cam. A driving force introducing gear is provided at the rear end of the sleeve connected to the shaft and connected to the sun gear. On the other hand, a motor is installed on the engine body, and the motor shaft meshes with the driving force introducing gear. Worm is provided. When the sun gear is stopped, the camshaft rotates at a constant reduction ratio with respect to the cam pulley, and when the sun gear is driven via a worm or the like by driving the motor, the phase of the camshaft changes. It has become.

As an improvement of the above-described variable valve timing device, a motor is arranged coaxially with the planetary gear mechanism, and the stator side of the motor is connected and fixed to the engine, while the rotor side is connected via a speed reduction mechanism. A variable valve timing device connected to the sun gear has also been developed.

[0005]

The conventional variable valve timing apparatus as described above has a relatively complicated structure, and is therefore assembled, for example, into an engine, replaced with a motor, or a cam pulley or a cam sprocket. At the time of maintenance work such as replacement of belts or chains attached to a vehicle, many parts must be attached or removed one by one in a predetermined order, and assemblability and maintainability are not necessarily good. There were drawbacks.

[0006] Therefore, in the valve timing device, it is particularly required to improve the assemblability and the maintainability. In order to improve the assemblability and the maintainability, it is desirable to adopt a rational configuration over the details of the apparatus so that the assemblability and the like can be further improved.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a variable valve timing device capable of improving assembling and maintenance.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a shaft which is disposed coaxially with a camshaft and one end of which is supported by the camshaft; An intermediate member mounted on the shaft member, and a driving unit that is disposed coaxially with the shaft body, has two members that can rotate relative to each other, and moves the intermediate member at least in the axial direction along the shaft body with the relative rotation. The camshaft is rotated coaxially with the camshaft via a camshaft-side drive wheel that is arranged at the end side of the camshaft and is drivingly connected to the crankshaft. And at least one of the rotational phase or the axial displacement of the camshaft with respect to the drive wheels by displacing in at least one of the directions to change the valve timing. Is provided with a case member detachable from the engine body, and the shaft body, the intermediate member and the driving means are integrally mounted on the case member and detachable from the engine body via the case member. (Claim 1).

According to this device, the shaft, the intermediate member, and the driving means are integrally mounted on the case member, and these can be integrally attached to and detached from the engine body. The assembling property or the maintenance property is improved.

The shaft member and the intermediate member are disposed so as to penetrate a rotor which is an inner peripheral member of the two members rotatable relative to each other, and rotate the rotor at a position corresponding to the rotor and the intermediate member. It is preferable that a feed screw for converting the axial movement of the member be formed, and that one end of the rotor in the rotation axis direction be supported in a state centered with respect to the case member. With this configuration, the intermediate member can be moved in the axial direction with the rotation of the rotor.
In addition, it becomes possible to favorably center the axially movable intermediate member via the rotor. In this case, if the one end side of the rotor in the rotation axis direction is supported by the bearing member, in particular, the case member via a ball bearing (claims 3 and 4), the wear of the centered portion is reduced. can do.

Further, in the apparatus according to any one of the first to fourth aspects, a first intermediate gear is connected to an end of the camshaft, and the camshaft is connected to the driving wheel with the rotation of the first intermediate gear. The two members of the driving means are arranged so as to penetrate the shaft and the intermediate member through the rotor which is the inner peripheral member, and the corresponding portions of the rotor and the intermediate member , A feed screw for converting the rotation of the rotor into the axial movement of the intermediate member is formed, and a second intermediate gear that can be meshed with the first intermediate gear is formed on the intermediate member. A helical gear that converts the axial movement of the intermediate member into rotation may be used, and the lead angle of the helical gear may be set to be larger than the lead angle of the feed screw. According to this, the rotation phase of the camshaft is changed with the movement of the intermediate member. At this time, since the lead angle of the second intermediate gear is larger than the lead angle of the feed screw, the rotation of the rotor is transmitted at a reduced speed. This is advantageous for reducing the driving torque of the driving means and improving the accuracy of the phase control. When the driving of the driving means is stopped,
With respect to the reaction force from the camshaft side, the action of holding the rotor in the stopped state is obtained by the frictional force of the feed screw.

According to the fifth aspect of the present invention, a planetary carrier and a ring gear for supporting a sun gear as the second intermediate gear and a planetary gear as the first intermediate gear are provided between the driving wheel and the camshaft. A planetary gear mechanism is interposed, and the two members, the ring gear and the planetary carrier, are disposed inside and outside in a rotatable state. If a configuration is adopted in which the side member is fixed to the camshaft (claim 6),
The planetary gear mechanism, drive wheels, camshaft, etc. are arranged coaxially, resulting in a compact configuration.
Assembly becomes easy.

The intermediate member and the shaft are spline-coupled (claim 7), and lubricating oil is supplied to the shaft at least between the intermediate member and the supporting portion of the shaft. It is desirable to form an oil passage that enables this.

Further, the shaft body is allowed to rotate relative to the case member so that the initial setting of the rotation phase can be performed at the time of assembly, or the rotation phase can be adjusted after maintenance. It is preferable that the supporting member be changeably supported between a rotation preventing state and a rotation preventing state (claim 9).
In this case, a flange is formed at one end of the shaft body, a friction plate is interposed between the flange and the case member, and the flange, the friction plate and the case member are pressed against each other in the mounted state. The fixing member may be provided detachably with respect to the case member. According to this, the rotation of the shaft body with respect to the case member is prevented by the frictional force of the friction plate when the shaft fixing member is mounted, and the frictional force is reduced and the rotation is permitted when the shaft fixing member is removed. Therefore, the shaft body can be changed between the rotation allowable state and the rotation prevention state with a simple configuration.

In each of the above devices, the driving means comprises, for example, an electric motor having, as two members capable of relative rotation, a stator in which field coils are arranged and a rotor in which permanent magnets are arranged. (Claim 11).

In this case, the rotation phase is controlled by electrically controlling the electric motor.

When the electric motor is employed as described above, the rotor is rotatably supported at one end in the direction of the rotation axis by the case member, and the portion supported by the case member is made of a non-magnetic material ( Claim 12). This makes it possible to appropriately support the rotor and effectively prevent leakage of magnetic flux to the case member side.

Further, between the driving wheel and the camshaft,
A planetary gear mechanism including a planetary carrier that supports the sun gear and the planetary gear and a ring gear is interposed. The two members of the ring gear and the planetary carrier are disposed inside and outside in a relatively rotatable state. In the case where the drive wheel is integrally provided on the member on the outer peripheral side, the end of the rotor on the camshaft side in the rotation axis direction can rotate with respect to at least one of the ring gear and the planetary carrier of the planetary gear mechanism. And at least one of the ring gear and the portion supported by the planetary carrier is made of a non-magnetic material. According to such a configuration, since one end side of the rotor is supported by the planetary gear mechanism, compactness can be achieved, and leakage of magnetic flux to the planetary gear mechanism side is also effectively prevented.

[0019] In the apparatus described in any one of the eleventh to thirteenth aspects, the rotor is supported at both ends in the rotation axis direction via thrust bearings. In this way,
An axial force acting on the rotor, such as a reaction force from the camshaft, can be appropriately received while rotatably supporting the rotor. In this case, if at least the contact portion of the rotor with the thrust bearing is made of a non-magnetic material (claim 15), leakage of magnetic flux can be effectively prevented.

On the other hand, in the device according to the present invention, at least one of both ends in the rotation axis direction of the rotor can be supported via a ball bearing (claim 16). With this configuration, the displacement of the rotor in the radial direction due to the action of the magnet is regulated, so that the centering state of the rotor is appropriately maintained. Therefore, an increase in friction loss with the feed screw portion of the slide member is suppressed, and power consumption during rotation of the rotor can be reduced.
In addition, an axial force acting on the rotor, such as a reaction force from the camshaft, can be appropriately received. Also in this case, if at least the contact portion of the rotor with the ball bearing is made of a non-magnetic material.
7) Leakage of magnetic flux can be effectively prevented.

The case member is provided with positioning portions for the stator and the rotor, respectively.
8). According to this, an air gap between the stator and the rotor can be appropriately and easily secured, and assemblability is improved.

An opening is formed in the case member so as to enable the rotation of the rotor from the outside.
9). According to this, it is possible to rotate the rotor from outside the case, and the convenience in initial setting of the rotation phase and maintenance is improved.

When an electric motor is used,
It is preferable to provide a magnetic pole detection sensor for detecting the magnetic pole of the permanent magnet of the rotor between the stator coils.
0). With this configuration, the cam angle can be detected based on the detection of the magnetic pole of the permanent magnet accompanying the rotation. In this case, unlike a position detecting device such as an encoder, the relative position between the rotor and the stator can be detected even during a plurality of rotations, and thus is particularly useful when the rotor rotates a plurality of times. ).

When each of the above-described variable valve timing devices is applied to a twin cam type engine, the feed screw twist direction is the same between the intake valve side and the exhaust valve side.
The torsional directions of the sun gear, the planetary gear and the ring gear are set in opposite directions. Further, the intermediate member on the intake side comes into contact with the front side of the engine at the most retarded angle, while the intermediate member on the exhaust side is the most advanced. Initially, an initial setting is made so as to contact the front side of the engine (claim 22).

According to such a configuration, the state in which the intermediate members on the intake side and the exhaust side come into contact with the front side of the engine is set as an initial setting state, and in this state, the overlap between the intake and exhaust can be minimized. By setting the above-mentioned initial setting state at the time of starting the engine, combustion stability can be ensured. Further, it is possible to suppress the wear of the intermediate member and the contact portion as compared with the case where the intermediate member is brought into contact with the contact (camshaft or the like) on the rear side of the engine.

[0026]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing an example of a variable valve timing apparatus according to the present invention. In this figure, 1
Is a camshaft 1 rotatably supported by an engine body (not shown), which opens and closes a valve with rotation. A cam pulley (drive wheel) 2 composed of a timing pulley (toothed pulley) is located around an end of the camshaft 1, and the cam pulley 2 is connected to a crank pulley mounted on a crankshaft (not shown) via a timing belt 3. Connected.

At the end of the camshaft 1, a planetary gear mechanism 10 and an electric motor 30 as driving means are provided, which are arranged coaxially with the camshaft 1 and the cam pulley 2.

The planetary gear mechanism 10 includes a sun gear 11
And a planetary carrier 12 (hereinafter abbreviated as carrier 12) for supporting a plurality of planetary gears 13 and a ring gear 14. The sun gear 11, the carrier 12 and the ring gear 14 are coaxially rotatably arranged. Have been. The cam pulley 2 is connected to the ring gear 14 and the camshaft 1 is connected to the carrier 12.

The electric motor 30 has a rotor 33 and a stator 31 rotatable relative to each other inside and outside.
Are connected and fixed to the engine body via the casing 35 and the bracket 4. Further, the rotor 33 of the electric motor 30 and the sun gear 11 of the planetary gear mechanism 10 are connected via a reduction mechanism. The speed reduction mechanism has a slide member (intermediate member) 44 that can move in the axial direction, and the sun gear 11 is connected to the slide member 44. As will be described in detail later, the rotation of the rotor 33 is converted into the axial movement of the slide member 44, and the sun gear 11 and the like are helical gears, whereby the axial movement of the slide member 44 is converted into rotation. And transmitted to the planetary gear mechanism 10.

Hereinafter, a specific configuration of the variable valve timing device will be described in detail.

The carrier 12 of the planetary gear mechanism 10 is
As shown in FIG. 2, the small-diameter portion 16
a and a through hole 16 in the front-rear direction having a large diameter portion 16b
The camshaft 1 is attached to the camshaft 1 in a state where the end of the camshaft is fitted into the large diameter portion 16b.
A bolt 18 is inserted from the front side through a bolt hole 17 formed around the small diameter portion 16a, and screwed into a screw hole 19 of the camshaft 1 so that the carrier is fixed to the camshaft 1. 12 are connected and fixed. Thus, the carrier 12 is centered on the camshaft 1 by connecting the camshaft 1 with the camshaft 1 fitted thereto.

The bolt hole 17 is formed as shown in FIG.
The carrier 12 and the camshaft 1 are interposed between the planetary gears 13 around the small-diameter portion 16a and thus utilize the space between the planetary gears 13.
And a compact fastening structure in which fastening positions are concentrated near the through hole 20 is achieved.

The cam pulley 2 is disposed on the outer peripheral side of the carrier 12, and is provided with two front and rear bearings 20.
It is rotatably supported on the outer peripheral side of the carrier 12 via a and 20b. A ring gear 14 is integrally fastened and fixed to the front end of the cam pulley 2.
Are engaged with the planetary gear 13.

The cam pulley 2 and the ring gear 14 are connected to the ring gear 14 at the front end of the cam pulley 2 as shown in FIG.
Are fitted into each other and are fastened to each other via a flange 21 provided continuously around the ring gear 14. Specifically, a bolt 23 is inserted from the front side into a bolt hole 22 formed in the flange 21, and is screwed into a screw hole 24 formed in the cam pulley 2 so that the ring gear 14 and the cam pulley 2 are integrated. It is fastened and fixed.
By fixing the ring gear 14 in the state of being fitted into the cam pulley 2, the ring gear 14 is centered with respect to the carrier 12 via the cam pulley 2 and the bearings 20a and 20b, and the ring gear 14 and the planetary gear 13 are appropriately fitted. It can be meshed.

The inner peripheral surface of the cam pulley 2 and the outer peripheral surface of the carrier 12 are formed with flanges 26 and 27, respectively.
End 14a and the bolt 1 on the front side of the carrier 12.
8 prevents the bearings 20a, 20b from being displaced in the front-rear direction. Specifically, the collar 2 is provided at the rear end of the carrier 12.
The cam pulley 2 has a flange 27 protruding substantially at the center of the cam pulley 2 in the front-rear direction, and a rear bearing 20b is interposed between the flanges 26, 27 so that the bearing 20b in the front-rear direction is provided. Movement is prevented. The front bearing 2 is located between the end portion 14a of the ring gear 14 and the washer 28 and the flange portion 27.
The interposition of Oa prevents the movement of the bearing 20a in the front-rear direction.

The front end 14b of the ring gear 14
Has a seal member 57 fitted on the inner peripheral side thereof,
The rear end of the rotor of the electric motor 30, which will be described later, is fitted inside the seal member 57.

On the other hand, the electric motor 30 comprises a stator 31 on which a stator coil 32 for a magnetic field is wound, and a rotor 33 on which a permanent magnet 34 is disposed. These constitute two members that can be relatively rotated.

The stator 31 is formed in a ring shape, and is fastened and fixed to a casing (case member) 35 connected to the engine body via the bracket 4 by bolts or the like. The casing 31 includes a stator 31.
Is formed, and the stator 31 is fixed to the casing 35 in a state where the stator 31 is positioned.

As shown in FIG. 4, the stator 31 is provided with Hall elements 55a to 55c, which are magnetic pole detection sensors, between three adjacent stator coils 32 of the stator 31. , These Hall elements 5
The magnetic poles of the permanent magnet 34 can be detected by 5a to 55c. That is, the rotation angle of the rotor 33 can be detected by detecting the magnetic pole of the permanent magnet 34 with the three continuous Hall elements 55a to 55c.

The rotor 33 is arranged on the inner peripheral side of the stator 31. And the front and rear sides of the rotor 33 are
The rotor 33 is rotatably supported on the inner peripheral side of the stator 31 by being connected to the casing 35 and the carrier 12 via thrust bearings 37a and 37b, respectively.

As shown in FIG. 2, the rotor 33 is provided integrally with holding portions 33a and 33b for bearings 37a and 37b, and the holding portions 33a and 33b are provided with bearings 37a and 33b.
A contact 38 is formed with respect to the outer peripheral side of a and 37b. On the other hand, the carrier 12 and the casing 35 are provided with washers 36 as holding portions for bearings 37a and 37b.
And a ring member 39 are attached.
In addition, bearings 37a, 37b are formed on the ring member 39 at the inner peripheral sides of the bearings 37a, 37b, respectively.
That is, each of the bearings 37a and 37b is
By centering the rotor 33 through the bearings 37a and 37b, the rotor 33 is held in a state fitted between the rotor 33a and 36a and 39a.

Although not shown, the ring member 39 is precisely attached to the casing 35 with a knock pin or the like, and the washer 36 is pressed against the support shaft of the planetary gear 13 so as to be attached to the carrier 12. It is attached precisely. By assembling the stator 31 and the rotor 33 with the stator 35 positioned with respect to the casing 35, the stator 31 and the permanent magnet 34
Gap (air gap) is appropriately secured. In order to prevent leakage of magnetic flux, the holding portions 33a and 33b of the rotor 33, the washer 36, the ring member 39, and the like are made of a non-magnetic material such as aluminum.

A shaft 42 extending in the front-rear direction coaxially with the camshaft 1 is inserted into the rotor 33. The shaft 42 has a front end supported by the casing 35 and a rear end supported by the camshaft 1 through the carrier 12 through the through hole 16.
The structure for supporting the shaft body 42 will be specifically described.
As shown in FIG.
A through hole 51 having a front and rear portion and a small diameter portion 51b is formed, and the shaft body 42 is inserted into the through hole 51.
A flange 43 is formed at a front portion of the shaft body 42. The collar 43 is interposed in the large diameter portion 51 a of the through hole 51, and friction plates 52 are provided before and after the collar 43. Have been. Then, the lid (shaft fixing member) 53 is fixed to the front end of the casing 35, so that the flange 4
3 is a cover 53 and a casing 35 via a friction plate 52.
Thus, the front end of the shaft body 42 is supported with respect to the casing 35 while being prevented from rotating.
On the other hand, the rear end of the shaft 42 protrudes into a recess 1 a formed in the front end of the camshaft 1, and the bush 5
4 and supported rotatably with respect to the camshaft 1.

The front end of the shaft 42 projects outside through an opening 53a of the lid 53 as shown in FIG. That is, although not shown in detail, a passage 42 a for supplying lubricating oil between the shaft 42 and the slide member 44 or between the shaft 42 and the bush 54 is provided inside the shaft 42. It is formed so that lubricating oil can be introduced into the passage 42a via the oil introduction section.

A cylindrical slide member 44 is provided on the outer peripheral side of the shaft body 42. Then, the shaft body 42
Corresponding axial splines 45 or serrations are formed on the outer circumference of the
The engagement of the splines 45 and the like makes it possible to move in the axial direction, that is, in the front-rear direction while the rotation of the slide member 44 is prevented.

A helical spline-shaped feed screw 46 is formed on the outer periphery of a front portion of the slide member 44, and a screw 47 meshing with the feed screw 46 is formed on the inner peripheral surface of the rotor 33. On the other hand, the rear part of the slide member 44 is located at the center of the planetary gear mechanism 10, and the sun gear 11 is integrally provided on the outer periphery of the rear part of the slide member 44. The sun gear 11, each planetary gear 13 meshing with the sun gear 11, and the ring gear 14 meshing with each planetary gear 13 are helical gears.

As shown in FIG. 5, the inclination α (lead angle) of the helical groove of the feed screw 46 with respect to the axis perpendicular to the axis of the slide member 44 is such that the helical groove of the helical gear constituting the sun gear 11 Is set to be smaller than the same slope β. Thereby, the rotor 33
Is reduced and transmitted to the planetary gear mechanism 10, and the stopped state of the rotor 33 is held against the thrust force acting on the slide member 44 from the camshaft side when the driving of the electric motor 30 is stopped. I am getting it.

Although not shown, the electric motor 30 is controlled by a controller that controls the engine as a whole, so that an optimal valve timing according to the operating state can be obtained in advance. The rotation phase of the camshaft 1 is set as described above, and the energization to the stator coil 32 of the electric motor 30 is controlled such that the rotation phase is changed according to the change in the operating state. During this control, the Hall elements 55a to 55
The rotation angle of the rotor 33 is obtained based on the detection of the magnetic pole by c, whereby the rotation phase is adjusted while the current cam angle is detected.

According to the above-described variable valve timing device, the driving of the electric motor 30 is stopped except when the phase is changed, and the sun gear 11 of the planetary gear mechanism 10 is fixed, so that the cam pulley 2 is connected to the cam pulley 2. Camshaft 1 connected to the connected ring gear 14 and carrier 12
Rotate at a speed ratio determined by the ratio of the number of teeth of the ring gear 14 and the number of teeth of the planetary gear 13. Then, by setting the pulley ratio between the crank pulley and the cam pulley 2 in consideration of the speed ratio in advance, the camshaft 1 rotates at a predetermined speed ratio with respect to the crankshaft.

When the phase is changed, the electric motor 30 is driven to rotate the rotor 33, and the rotation is converted by the feed screws 46 and 47, so that the slide member 44 and the sun gear 11 integrated therewith are formed. It moves in the axial direction, and the movement in the axial direction is converted into the rotational direction by the helical gear constituting the sun gear 11 and the like, and the rotational force is applied from the sun gear 11 to the planetary gear 13. As a result, the speed ratio between the ring gear 14 and the carrier 12 changes as compared with the case where the sun gear 11 is fixed, whereby the rotation phase of the camshaft 1 changes and valve timing is changed.

Incidentally, the above-described variable valve timing device is composed of two units as a whole. Specifically, a first unit composed of the cam pulley 2, the carrier 12, and the ring gear 14 and connected and fixed to the camshaft 1, the casing 35, the electric motor 30 attached thereto, and the shaft 42 And a second unit constituted by a slide member 44 and the like and fastened and fixed to the engine body via the bracket 4. Therefore, at the time of assembling to the engine main body, for example, each unit is sub-assembled, and these units are assembled to the engine main body.

The assembly of the first unit is performed, for example, by
First, for the carrier 12 before the planetary gear is attached,
After mounting the bearing 20b, the cam pulley 2, the bearing 20a, and the washer 36 in this order, the ring gear 14 is fitted into the cam pulley 2 and fastened and fixed.
The planetary gear 13, the washer 36, and the bearing 37b are mounted in this order to assemble. As a result, the cam pulley 2 and the ring gear 14 are rotatably supported outside the outer periphery of the carrier 12, and at the center thereof,
As a whole, a first unit in a ring shape having a receiving portion of the sun gear 11 including the through hole 16 is completed.

On the other hand, assembling the second unit first
After the ring member 39, the bearing 37a, and the electric motor 30 are mounted on the casing 35 in this order,
1, the shaft 42 is inserted into the casing 35, and the friction plate 52 and the lid 53 are attached. At this time, the lid 53 is temporarily fixed. Finally, the feed screw 46 of the slide member 44 is engaged with the screw 47 of the rotor 33 while the slide member 44 is inserted through the shaft 42. Thereby, the second unit is completed.

On the other hand, when assembling the variable valve timing device to the engine body, first, the first unit is mounted on the camshaft 1. The installation of the first unit
The first unit is mounted on the end of the camshaft 1 while fitting the tip of the camshaft 1 into the through hole 16 of the carrier 12, and then the carrier 12 is fastened and fixed to the camshaft 1 by bolts 18. .

When the mounting of the first unit is completed, the second unit is mounted on the camshaft 1 and the second unit. Specifically, the shaft 4
2 is inserted into the through hole 16 of the carrier 12 (right end in FIG. 1).
, The second unit is combined with the first unit while the sun gear 11 of the slide member 44 is meshed with the planetary gear 13. At this time, a seal member 57 is previously attached to the front end of the ring gear 14, and the rotor 33 is fitted to the bearing 37b and the seal member 57 at the time of merging. After the second unit is combined with the first unit, the casing 35 is fastened and fixed to the bracket 4.

After each unit is attached to the engine body, the rotor 33, the cam pulley 2 and the shaft 42 are appropriately rotated to initialize the rotation phase. At this time, the lid 53 is removed from the casing 35 and the friction plate 52
By releasing the clamped state of the collar 43 by the shaft member 42 and the slide member 44, the casing 35
, So that the rotation phase can be initialized. In the present embodiment, a plurality of elongate service holes 56 are formed in the casing 35 around the through hole 51 in the circumferential direction. When the rotor 33 is rotated, the shaft 33 is formed through the service hole 56. The rotor 33 can be rotated using a jig or the like.

After the initial setting of the rotation phase is completed, the lid 53 is fastened and fixed to the casing 35. As a result, the rotation of the shaft body 42 and the slide member 44 with respect to the casing 35 is stopped, the initial setting is completed, and the assembly of the valve timing device with respect to the engine body is completed.

According to the variable valve timing device configured as described above, since the planetary gear mechanism 10 is used as described above, space saving of the device can be effectively achieved.

Further, the whole is constituted by a first unit including the cam pulley 2, the carrier 12, the ring gear 14, and the like, and a second unit including the electric motor 30, the shaft 42, the slide member 44, and the like. At the time of assembling to the engine, the units can be easily assembled to the engine body by assembling the units while being combined, so that the assembling property is extremely good. Therefore, according to this device, it is possible to satisfactorily achieve compactness of the device and improvement of assembling property.

Another feature is that since the device can be removed in units of each unit, maintenance is easy. For example, when attaching / detaching the timing belt 3, even if the electric motor 30 is large and obstructs attachment / detachment of the belt, it is easy to remove the belt from the cam pulley 2 simply by removing the second unit. Can be detached. Therefore, there is a feature that the maintainability is extremely good as compared with a conventional apparatus of this type, which requires replacing the belt while removing a large number of parts in a predetermined order.

The above configuration is an example of the variable valve timing apparatus according to the present invention, and the specific configuration can be changed as appropriate without departing from the gist of the present invention.

For example, in the above-described embodiment, the Hall elements 55a to 55c are provided on the stator 31 of the electric motor 30, and the rotation angle of the rotor 33 is obtained based on the detection of these magnetic poles to detect the cam angle. But of course,
The cam angle may be detected by using a conventional cam angle sensor that detects a detection plate mounted on the camshaft by a sensor. In addition, as a method of obtaining the cam angle by obtaining the rotation angle of the rotor 33, it is conceivable to attach an encoder to the electric motor 30, but in this case, when the rotor 33 rotates plural times, The rotation angle cannot be determined. Therefore, the configuration of the above-described embodiment is particularly useful for controlling the rotation phase when the rotor 33 makes multiple rotations.

In the first unit of the above embodiment, the cam pulley 2 is rotatably supported on the outer peripheral side of the carrier 12 and the ring gear 14 is attached to the front end of the cam pulley 2. A configuration in which 14 and the carrier 12 are replaced inside and outside may be adopted. FIG. 6 schematically shows one example, and this example will be described below. Note that FIG.
1 are assigned the same reference numerals as in FIG.
Only the differences from this device will be described.

In the apparatus shown in this figure, a through hole 60 for receiving a camshaft is formed integrally with the ring gear 14,
The front end of the camshaft 1 is fitted to the rear side of the through hole 60, and the ring gear 14 is fastened and fixed to the camshaft 1 in this state. In the ring gear 14, a cam pulley 2 is provided on the outer peripheral side of the through hole 60, and the cam pulley 2 is rotatably supported by the ring gear 14 via bearings 20a and 20b. A carrier 12 is connected and fixed to the front end of the cam pulley 2, and a planetary gear 13 supported by the carrier 12 meshes with the ring gear 14 and the sun gear 11. According to the configuration as shown in this figure, the sun gear 1 of the planetary gear mechanism 10 except when the phase is changed.
When the cam gear 1 is fixed, the cam pulley 2 and the planetary gears 13 and the ring gear 14 of the carrier 12 connected thereto rotate, whereby the camshaft 1 rotates at a predetermined speed ratio with respect to the crankshaft.

When the phase is changed, the electric motor 30
Is driven to rotate the rotor 33, the slide member 44 and the sun gear 11 integrated therewith move in the axial direction, and a rotational force is applied from the sun gear 11 to the planetary gear 13. As a result, the ring gear 14 and the carrier 12 are compared with the case where the sun gear 11 is fixed.
, And the rotational phase of the camshaft 1 changes, thereby changing the valve timing.

Since the apparatus shown in FIG. 6 has no functional difference from the apparatus shown in FIG. 1, there is no great difference in adopting any of the apparatuses. However, it can be said that the apparatus shown in FIG. 1 is slightly more advantageous in terms of space. That is, in the apparatus of FIG. 6, since the bearings 20a and 20b and the carrier 12 are disposed on the outer peripheral side of the ring gear 14, if the gear configurations of the sun gear 11, the planetary gear 13 and the ring gear 14 are the same, the outer peripheral side of the ring gear 14 The apparatus of FIG. 1 in which only the cam pulley 2 is provided is more compact in the radial direction. Therefore, the apparatus of FIG. 1 is more useful in consideration of space efficiency.

In the case of a twin cam (DOHC) engine in which the intake valve and the exhaust valve are operated by different camshafts, a variable valve timing device may be provided for each of the intake and exhaust camshafts. In this case, for example, the variable valve timing devices on the intake side and the exhaust side may be configured as follows.

That is, for the device on the intake side, FIG.
In the configuration shown in FIG. 5, the initial setting is performed so that the front end side of the slide member 44 contacts the stopper 35a of the casing 35 at the most retarded angle (see FIG. 5). On the other hand, the exhaust-side device is based on the configuration of FIG. 1 and has a sun gear 1 having a helical structure opposite to that of the intake side as shown in FIG.
1 'and the planetary gear 13', and the front end side of the slide member 44 'is
Initial setting is performed so as to hit the stopper 35a. By configuring the devices on the intake side and the exhaust side in this way, in the initial setting state, the overlap between intake and exhaust can be minimized, and combustion stability can be ensured when the engine is started. In addition, since the slide members 44, 44 'on the intake side and the exhaust side can be brought into contact with the stopper 35a provided fixedly, there is an advantage that the wear of the slide members 44, 44' can be effectively prevented. That is, in the initial setting state, the slide members 44, 44 'may be brought into contact with a camshaft or the like (a contact on the rear side of the engine). In this case,
Since the camshaft 1 rotates, the slide members 44, 4
4 'and the friction of the camshaft 1 are feared. However, according to the above configuration, such wear can be avoided.

In the above-described variable valve timing device, the electric motor 30 is used as the drive source. However, the configuration using the electric motor 30 as the drive source is not limited to the above-described initial setting (FIG. 5). , FIG. 7).

That is, the overlap of intake and exhaust is generally minimized when the engine is started or idling. Therefore, in each of the above-described variable valve timing devices, the initial setting state can be maintained at the time of starting or idling. Required. However, in the variable valve timing device on the exhaust side which is set to the most advanced angle in the initial setting state, the slide member 44 'tends to shift in the retard direction due to the reaction force from the valve side when the engine is driven, and it is necessary to prevent this. In this regard, according to the variable valve timing device using the electric motor 30 as a drive source, the displacement of the slide member 44 'can be reliably prevented by driving the motor 30 even immediately after the engine is started. In other words, a hydraulic motor may be used as the drive source. In this case, however, it takes time until the hydraulic pressure is sufficiently increased after the start, and the displacement of the slide member 44 'may not be sufficiently prevented. Therefore, a configuration using the electric motor 30 as a driving source is useful in an apparatus for performing the initial setting as described above.

The above embodiment is an example in which the device of the present invention is applied to an engine of a type in which the valve timing is changed by rotating a cam shaft relative to a pulley. For example, the present invention is also applicable to an engine of a type in which a valve timing is changed by moving a camshaft in the axial direction. FIG. 9 shows a main part of such an engine.

That is, in this engine, a drive cam 72 is provided on a camshaft 71, and a swing cam 73 is interposed between the drive cam 72 and the valve 70. The driving cam 72 has a predetermined length in the axial direction, and a tapered cam surface 74 is formed on an outer peripheral surface thereof. On the other hand, the swing cam 73 is pivotally supported by a swing cam shaft 75, and has a tapered cam surface 74 of the drive cam 72 on the upper surface side.
A cam follower portion 76 is formed so as to slidably contact the upper surface of the valve 70 on the lower surface side. The swing cam 73 swings with the rotation of the drive cam 72 to open and close the valve 70, and the drive cam 7 moves by the axial movement of the cam shaft 71.
The sliding position between the second tapered cam surface 74 and the cam follower portion 76 of the swing cam 73 changes in the axial direction, whereby the lift amount and the valve opening timing of the valve 2 change.

In the case of such an engine, for example,
As in the case of the slide member 44 in FIG. 1, a member (intermediate member) that is moved in the axial direction by the driving means is provided, and a configuration in which the camshaft is interlocked with the movement of the member is often adopted. Therefore, in the case of such a configuration, it is possible to improve assemblability by attaching the intermediate member, the driving means, and the like to the casing or the like so as to be detachable from the engine body.

In the above embodiment, the rotor 3
Although the thrust bearing 37a is provided on the front side of 3, the ball bearing 62 may be provided as shown in FIG. According to such a configuration, since the radial displacement of the rotor 33 is regulated by the ball bearing 62, the rotor 33 is attracted in the radial direction by the magnetic force of the permanent magnet 34, and the centering state of the rotor 33 is hindered. Can be effectively prevented. Further, the ball bearing 62 can regulate thrust in the axial direction, and can appropriately receive an axial force acting on the rotor 33 such as a reaction force from the camshaft 1 side. Further, the inner ring 63 of the ball bearing 62
And the outer ring 64 are in contact with the casing 35 and the rotor 33, respectively.
Centered at 5. Therefore, the centering accuracy is improved, and the wear of the support portion can be reduced. Also, screws 46,
It is possible to suppress an increase in friction loss between the rotors 47, and as a result, it is possible to reduce power consumption during rotation of the rotor and the like.

[0076]

As described above, according to the present invention, there is provided a shaft body coaxially arranged with a camshaft and having one end supported by the camshaft, and an intermediate body movably mounted on the shaft body. A member and a driving unit that is disposed coaxially with the shaft body and has two members that are relatively rotatable and that moves the intermediate member along the shaft body with the relative rotation thereof, and is connected to the crankshaft. While rotating the camshaft via the drive wheels, the camshaft is rotated or axially displaced with the movement of the intermediate member, so that the rotation phase of the camshaft with respect to the drive wheels is changed, and A removable case member is provided, the shaft body, the intermediate member, and the driving means are integrally mounted on the case member, and integrated with the engine body via the case member. Since it is detachably configured, assembly of conventional when compared to this kind of device the variable valve timing device for an engine, or the maintenance it is remarkably improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a variable valve timing device according to the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part of the variable valve timing device;

FIG. 3 is a schematic front view showing a fastening structure of the planetary carrier.

FIG. 4 is a schematic front view showing an electric motor.

FIG. 5 is an explanatory view showing a structure of a feed screw and a sun gear of a slide member.

FIG. 6 is a sectional view showing another example of the variable valve timing device of the present invention.

FIG. 7 is an explanatory view showing the structures of a feed screw and a sun gear of a slide member when the variable valve timing device of the present invention is applied as a variable valve timing device on the exhaust side of a twin cam (DOHC) engine.

FIG. 8 is an explanatory diagram showing an example of intake and exhaust timing when the variable valve timing device of the present invention is applied to a twin cam (DOHC) engine.

FIG. 9 is a schematic perspective view showing an example of an engine configuration to which the present invention is applied.

FIG. 10 is a view corresponding to FIG. 2, showing another example of the variable valve timing device of the present invention.

[Description of Signs] 1 Camshaft 2 Cam pulley 3 Timing belt 4 Bracket 10 Planetary gear mechanism 11 Sun gear 12 Carrier 13 Planetary gear 14 Ring gear 30 Electric motor 31 Stator 33 Rotor 35 Casing 42 Shaft 44 Shaft 44 Slide member 46, 47 Feed screw

Claims (22)

[Claims] 1. A shaft body coaxially arranged with a camshaft, one end of which is supported by the camshaft, an intermediate member movably mounted on the shaft body, and coaxially arranged with the shaft body. A driving means for moving the intermediate member at least in the axial direction along the shaft body in accordance with the relative rotation of the two members. The camshaft is driven via a camshaft-side drive wheel that is drivingly connected to a crankshaft, and the camshaft is displaced in at least one of a rotational direction and an axial direction with the movement of the intermediate member. The valve timing is changed by performing at least one of the rotation phase and the axial displacement of the camshaft with respect to the valve shaft, and is detachable from the engine body. That the shaft, the intermediate member, and the driving means are integrally mounted on the case member and configured to be integrally detachable from the engine body via the case member. Characteristic variable valve timing device. 2. The shaft member and the intermediate member are arranged so as to penetrate a rotor, which is an inner peripheral member, of the two relatively rotatable members, and the rotor is disposed at a position corresponding to the rotor and the intermediate member. A feed screw for converting rotation to axial movement of the intermediate member is formed, and one end of the rotor in the rotation axis direction is supported in a state of being centered with respect to the case member. 2. The variable valve timing device according to claim 1. 3. The variable valve timing device according to claim 2, wherein one end of the rotor in the rotation axis direction is supported by the case member via a bearing member. 4. The variable valve timing device according to claim 3, wherein said bearing member is a ball bearing. 5. A first intermediate gear is connected to an end of the camshaft, and the camshaft is configured to rotate relative to the drive wheels with rotation of the first intermediate gear. Of the two members, the shaft member and the intermediate member are arranged so as to penetrate the rotor which is the member on the inner peripheral side, and the rotation of the rotor is moved in the axial direction of the intermediate member at a position corresponding to the rotor and the intermediate member. A feed screw for conversion is formed, and a second intermediate gear that can mesh with the first intermediate gear is formed on the intermediate member, and the second intermediate gear converts the axial movement of the intermediate member into rotation. 5. The variable valve timing device according to claim 1, wherein the helical gear is a helical gear, and a lead angle of the helical gear is set to be larger than a lead angle of the feed screw. . 6. A planetary gear mechanism comprising a planetary carrier and a ring gear for supporting a sun gear as the second intermediate gear and a planetary gear as the first intermediate gear is interposed between the drive wheel and the camshaft. The two members of the ring gear and the planetary carrier are disposed inside and outside in a rotatable state, and the drive wheel is integrally provided on an outer member of the two members, while an inner member is provided. 6. The variable valve timing device according to claim 5, wherein the valve is fixed to the camshaft. 7. The variable valve timing device according to claim 1, wherein the intermediate member and the shaft body are spline-coupled. 8. An oil passage which is capable of supplying lubricating oil to at least one of the shaft member and the intermediate member and between the shaft member and a support portion of the shaft member. The variable valve timing device according to claim 1. 9. The system according to claim 1, wherein the shaft body is supported so as to be changeable between a rotation allowable state in which rotation of the case member is allowed and a rotation inhibition state in which rotation is prevented. 9. The variable valve timing device according to any one of claims 1 to 8. 10. A flange is formed at one end of the shaft, a friction plate is interposed between the flange and the case member, and is detachable from the case member. 10. The variable valve timing device according to claim 9, further comprising a shaft fixing member for pressing the collar, the friction plate and the case member against each other. 11. The driving means comprises an electric motor having, as two relatively rotatable members, a stator in which field coils are arranged and a rotor in which permanent magnets are arranged,
The variable valve timing device according to any one of claims 1 to 10, wherein a stator side is fixedly connected to the case member. 12. The rotor according to claim 11, wherein one end of the rotor in the rotation axis direction is rotatably supported by the case member, and a portion supported by the case member is formed of a non-magnetic material. The variable valve timing device as described in the above. 13. A planetary gear mechanism comprising a planetary carrier and a ring gear for supporting the sun gear and the planetary gear is interposed between the drive wheel and the camshaft, and the two members of the ring gear and the planetary carrier rotate relative to each other. As well as being installed inside and outside as possible,
The drive wheel is integrally provided on an outer peripheral member of the two members, and the end of the rotor on the camshaft side in the rotation axis direction is at least one of a ring gear and a planetary carrier of a planetary gear mechanism. The ring gear and a portion supported by the planetary carrier are formed of a non-magnetic material.
Or the variable valve timing device according to 12. 14. The variable valve timing device according to claim 11, wherein the rotor is supported at both ends in the rotation axis direction via thrust bearings. 15. The variable valve timing device according to claim 14, wherein the rotor has at least a portion in contact with the thrust bearing made of a non-magnetic material. 16. The variable valve timing according to claim 11, wherein at least one end of both ends in the rotation axis direction of the rotor is supported via a ball bearing. apparatus. 17. The variable valve timing device according to claim 16, wherein at least a portion of the rotor contacting the ball bearing is formed of a non-magnetic material. 18. The variable valve timing device according to claim 11, wherein the case member is provided with positioning portions for the stator and the rotor, respectively. 19. The variable valve timing device according to claim 11, wherein an opening is formed in the case member to enable rotation of the rotor from outside. 20. The magnetic sensor according to claim 1, wherein the stator is provided with a magnetic pole detection sensor for detecting a magnetic pole of a permanent magnet of a rotor between adjacent stator coils.
20. The variable valve timing device according to any one of 1 to 19. 21. The variable valve timing device according to claim 20, wherein the rotor rotates a plurality of times with respect to the stator. 22. An apparatus applied to a twin-cam type engine, wherein a twisting direction of the feed screw is the same between the intake valve side and the exhaust valve side, and each of the sun gear, the planetary gear and the ring gear has The torsional direction is set to the opposite direction, and the initial setting is made so that the intake side contacts the front side of the engine at the most retarded angle, while the exhaust side contacts the front side of the engine at the most advanced angle. The variable valve timing device according to claim 2.