JPWO2010095257A1 - Engine phase variable device - Google Patents

Abstract

Transmission of torque between a clutch case and a rotating drum is performed using an oil film. A phase of an engine that changes the opening / closing timing of an intake valve or an exhaust valve by causing relative rotation between an outer cylinder part 10 and an inner cylinder part 20 by moving an intermediate member 30 in an axial direction. The apparatus includes an annular rotating drum 44 connected to the intermediate member 30 and an electromagnetic clutch 42 that controls a braking force against the rotating drum 44 according to the operating state of the engine. The electromagnetic clutch 42 is opposed to the rotating drum 44. And an electromagnetic coil 62 that generates a braking force against the rotating drum 44 when energized. A groove 66 is formed in the end surface 63a of the inner peripheral wall 63 and the end surface 64a of the outer peripheral wall 64 of the clutch case 60. 67, and the transmission of torque between the rotary drum 44 and the clutch case 60 is transmitted through the grooves 66, 67 and an oil film formed around the grooves 66, 67. And do it. [Selection] Figure 1

Description

The present invention relates to an engine phase variable device that applies a braking force to a rotating drum by an electromagnetic clutch to change the rotational phase of a camshaft with respect to a sprocket to change the opening / closing timing of a valve.

As this type of phase varying device, for example, a sprocket to which the driving force of an engine crankshaft is transmitted and a camshaft constituting a valve mechanism are configured to rotate integrally. However, if a braking force is applied to the rotating drum by the electromagnetic brake means, the rotating drum has a rotation delay with respect to the sprocket, and the camshaft phase relative to the sprocket is linked to the rotation delay of the rotating drum. Have been proposed (see Patent Document 1).

In this phase variable device, an oil passage provided in the camshaft, an oil reservoir provided radially inside the clutch case, and an inner peripheral wall of the clutch case are disposed in a relative sliding portion between the friction material of the clutch case and the rotary drum. Since the structure in which engine oil is introduced through an oil introduction notch provided at the edge is adopted, the relative sliding surfaces of the friction material and the rotating drum can be cooled.

JP 2002-371814 A (see pages 4 to 6, see FIGS. 1 to 4)

  A phase varying device described in Patent Document 1 is a clutch case in which an electromagnetic clutch constituting an electromagnetic brake means is prevented from rotating in a circumferential direction with a U-shaped cross section that opens toward a disk surface of a rotating drum. And an electromagnetic coil housed in the clutch case, a friction material holding plate fixed to the inside of the opening of the clutch case, and a surface adhered to the friction material holding plate from the front edge portion of the inner and outer peripheral walls of the clutch case It consists of a flat friction material that protrudes slightly, and since a fiber friction material is used as the friction material, it is possible to convert the suction force generated from the electromagnetic clutch into brake torque and transmit it to the rotating drum reliably. it can.

  However, if the fiber friction material is continuously used, it will be clogged, resulting in a significant μ drop. For this reason, when a fiber type friction material is used for the electromagnetic clutch, there is a limit to the frequency of use in an actual vehicle.

  Further, in order to suppress variations in the attractive force generated from the electromagnetic clutch, the surface of the fiber friction material and the gap (air gap) between the clutch case and the rotating drum must be processed with high accuracy. However, it is necessary to use special equipment to process the air gap with high accuracy and to measure the processing state of the air gap.

The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide an engine phase variable device capable of transmitting torque between a clutch case and a rotating drum using an oil film. There is to do.

  In order to achieve the above object, in the phase varying apparatus for an engine according to claim 1, an outer cylinder part to which rotation of the crankshaft of the engine is transmitted, an intake valve of the engine that is relatively rotatable to the outer cylinder part, or An intermediate cylinder connected to a camshaft for opening and closing the exhaust valve, and an intermediate member disposed between the outer cylinder and the inner cylinder and transmitting the rotational force of the outer cylinder to the inner cylinder The phase of the engine changes the opening / closing timing of the intake valve or the exhaust valve by causing relative rotation between the outer cylinder part and the inner cylinder part by moving the intermediate member in the axial direction. The variable device includes: an annular rotating drum disposed around the inner cylinder portion and connected to the intermediate member; and an electromagnetic clutch that controls a braking force against the rotating drum according to an operating state of the engine. Kula H includes an annular clutch case disposed opposite to the rotating drum, and an electromagnetic coil that generates a braking force against the rotating drum by moving the clutch case toward the rotating drum when energized. A groove for forming an engine oil passage is formed on at least one of the facing surface of the drum facing the clutch case or the facing surface of the clutch case with the rotating drum, and the rotating drum and the clutch The torque is transmitted to and from the case through the groove and an oil film formed around the groove.

(Operation) When the electromagnetic coil is energized, the clutch case moves toward the rotating drum and a braking force is generated from the electromagnetic coil to the rotating drum. At this time, since the oil film is formed in and around the groove formed on the surface of the rotating drum facing the clutch case or the surface of the clutch case facing the rotating drum, the torque between the clutch case and the rotating drum Can be transmitted using an oil film. For this reason, when torque is transmitted between the clutch case and the rotating drum, a high μ (friction coefficient) can be obtained without attaching a fiber friction material or the like between the clutch case and the rotating drum.

The engine phase varying device according to claim 2 is the engine phase varying device according to claim 1, wherein the annular clutch case is formed in a U-shaped cross section, and has an inner peripheral wall and an outer peripheral wall. The electromagnetic coil is housed in an enclosed annular groove, the groove is formed on a surface of the outer peripheral wall facing the rotating drum, and a gap is formed between the inner peripheral wall and the rotating drum, Transmission of torque between the rotating drum and the clutch case is performed through the groove formed in the outer peripheral wall and an oil film formed around the groove.

(Function) When torque is transmitted between the clutch case and the rotating drum using an oil film, a groove is formed between the inner peripheral wall and the rotating drum, and a groove formed on the outer peripheral wall and its surroundings are formed. It can carry out using the oil film formed in this. For this reason, the clearance gap (air gap) between an inner peripheral wall and a rotating drum can be adjusted easily.

  As is apparent from the above description, according to the engine phase varying device according to the first aspect, high μ can be obtained without attaching a fiber friction material or the like between the clutch case and the rotating drum.

  According to the engine phase varying apparatus according to the second aspect, the gap (air gap) between the inner peripheral wall and the rotating drum can be easily adjusted.

1 is a longitudinal sectional view of an engine phase varying device showing a first embodiment of the present invention. It is a perspective view which shows the internal structure of the phase variable apparatus of the engine which concerns on this invention. It is a front view of a clutch case. It is sectional drawing which follows the AA line of FIG. It is principal part sectional drawing of the clutch case and rotary drum in 1st Example of this invention. It is an expanded sectional view of the groove | channel formed in the clutch case. It is principal part sectional drawing of a clutch case and a rotating drum which shows 2nd Example of this invention. It is principal part sectional drawing of a clutch case and a rotating drum which shows 3rd Example of this invention. It is principal part sectional drawing of a clutch case and a rotating drum which shows 4th Example of this invention. It is a principal part front view of the clutch case which shows 4th Example of this invention. It is principal part sectional drawing of a clutch case and a rotating drum which shows 5th Example of this invention. It is principal part sectional drawing of a clutch case and a rotating drum which shows 6th Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Toroidal outer cylinder part 20 Toroidal inner cylinder part 30 Intermediate member 42 Electromagnetic clutch 44 Rotary drum 44a Disk surface 60 Clutch case 62 Electromagnetic coil 63 Inner peripheral wall 63a End surface 64 Outer peripheral wall 64a End surface 66, 67 Groove

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of an engine phase varying device according to a first embodiment of the present invention, FIG. 2 is a perspective view showing the internal structure of the device, FIG. 3 is a front view of a clutch case, FIG. FIG. 5 is a cross-sectional view taken along the line AA of FIG. 3, FIG. 5 is a cross-sectional view of main parts of the clutch case and the rotating drum in the first embodiment of the present invention, and FIG. FIG. 7 is a cross-sectional view of main parts of a clutch case and a rotating drum showing a second embodiment of the present invention, and FIG. 8 is a cross-sectional view of main parts of the clutch case and the rotating drum showing a third example of the present invention. FIG. 9 is a cross-sectional view of main parts of a clutch case and a rotating drum according to a fourth embodiment of the present invention, FIG. 10 is a front view of main parts of the clutch case according to the fourth embodiment of the present invention, and FIG. FIG. 12 is a sectional view of essential parts of a clutch case and a rotating drum showing a fifth embodiment of the present invention. It is a fragmentary cross-sectional view of a rotary drum and clutch case showing an embodiment.

  1 and 2, the phase varying device for an engine in this embodiment is used in an engine oil atmosphere in a form assembled and integrated with an automobile engine, for example, and an intake / exhaust valve is synchronized with rotation of a crankshaft. The rotation of the crankshaft is transmitted to the camshaft so as to open and close, and the opening / closing timing of the intake / exhaust valve of the engine is changed according to the operating state such as the engine load and rotation speed.

Specifically, the phase varying device of the engine includes an annular outer cylinder portion 10 that is a sprocket to which the driving force of the crankshaft of the engine is transmitted, and an outer cylinder portion 10 that is disposed coaxially with the outer cylinder portion 10. Relative rotation is possible, and the driven annular inner cylinder part 20 constituting a part of the camshaft 2, the outer cylinder part 10 and the inner cylinder part 20 are respectively helically spline-engaged with the outer cylinder part 10 and the inner cylinder. An intermediate member 30 that is interposed between the portions 20 and moves in the axial direction to change the phase of the inner tube portion 20 with respect to the outer tube portion 10, and is provided on the camshaft 2 non-installation side of the inner tube portion 20. And an electromagnetic brake means 40 for moving the member 30 in the axial direction. The electromagnetic brake means 40 is attached to a cover (engine case) 8.

  The outer cylinder portion 10 includes a sprocket body 12 having a ring-shaped recess 13 provided on the inner periphery thereof, and an inner flange that is in close contact with the side surface of the sprocket body 12 and cooperates with the recess 13 to define a flange engagement groove 13A. The plate 14 and the inner flange plate 14 are fastened together and fixed to the sprocket body 12, and a spline case 16 having a spline engaging portion with the intermediate member 30 formed on the inner periphery is constituted.

Between the large-diameter concave portion 13a on the opening side of the concave portion 13 and the small-diameter concave portion 13b on the heel side of the concave portion 13, a step portion 13c is provided to face the outer peripheral edge of the flange 24 on the inner cylinder portion 20 side described later. Yes.

The rotation of the crankshaft of the engine is transmitted through the chain C to the outer cylinder portion 10 (sprocket body 12) which is a sprocket. Reference numeral 11 denotes a fastening screw for fixing and integrating the sprocket body 12, the inner flange plate 14, and the spline case 16, and the sprocket (outer cylinder portion 10) is constituted by the sprocket body 12, the inner flange plate 14, and the spline case 16. The flange engaging groove 13A can be easily formed, and the spline engaging portion 17 in the outer cylinder portion 10 (spline case 16) can be easily formed.

  Further, male and female helical splines 32 and 33 are provided on the inner and outer peripheral surfaces of the intermediate member 30, and a male helical spline 23 is provided on the outer peripheral surface of the inner cylinder portion 20. A female helical spline 17 is provided on the inner peripheral surface of the spline case 16. Since the inner and outer splines 32 and 33 of the intermediate member 30 are formed as reverse helical splines, the phase of the inner cylinder portion 20 is changed with respect to the outer cylinder portion 10 by a slight movement of the intermediate member 30 in the axial direction. It can be changed greatly. A male screw part 31 is formed on the outer peripheral surface of the intermediate member 30.

  The electromagnetic brake means 40 is rotatably supported on the inner cylinder portion 20 by the electromagnetic clutch 42 supported by the cover (engine case) 8 and the bearing 22, and the male screw portion 31 of the intermediate member 30 is screwed together. The rotating drum 44 to which the braking force of the electromagnetic clutch 42 is transmitted, and the torsion coil spring 46 interposed in the axial direction between the rotating drum 44 and the outer cylinder portion 10 are configured.

The electromagnetic clutch 42 is mounted on the outer peripheral side of the boss portion 8 a of the cover 8. A female square screw portion 45 is provided on the inner peripheral surface of the rotary drum 44, and the rotary drum 44 and the intermediate member 30 can be relatively rotated along the square screw portions 45 and 31 in the circumferential direction. That is, the intermediate member 30 can move in the axial direction while rotating along the square screw portions 45 and 31.

Further, the rotating drum 44 and the outer cylinder portion 10 are connected by a wound torsion coil spring 46. When no braking force is applied to the rotating drum 44, the outer cylinder portion 10, the inner cylinder portion 20, and the intermediate member. 30 and the rotating drum 44 rotate together. Further, since the torsion coil spring 46 interposed between the rotating drum 44 and the outer cylinder portion 10 (spline case 16) is interposed in the axial direction, the entire phase variable device extends in the axial direction, but the radial direction. It is compact.

  By controlling ON / OFF of the electromagnetic clutch 42 and the energization amount to the electromagnetic clutch 42, the intermediate member 30 moves in the axial direction while rotating along the square screw portions 45, 31, thereby the outer cylinder. The phase of the part 10 and the inner cylinder part 20 changes, and the timing of opening and closing of the valve by the cam 2a of the camshaft 2 is adjusted.

That is, before the electromagnetic clutch 42 is turned on (when no power is supplied), the electromagnetic clutch 42 is in the position indicated by the phantom line in FIG. 1, and a gap S is formed between the rotating drum 44 and the electromagnetic clutch 42. The outer cylinder part 10 and the inner cylinder part 20 rotate together without any phase difference. When the electromagnetic clutch 42 is turned on (energized), the electromagnetic clutch 42 slides in the right direction in FIG. 1 to attract the rotating drum 44, whereby the braking force transmitted from the electromagnetic clutch 42 acts on the rotating drum 44. .

Then, a rotation delay with respect to the outer cylinder portion 10 occurs in the rotating drum 44 to which the braking force acts, that is, the intermediate member 30 moves forward (moves in the right direction in FIG. 1) by the square screw portions 31 and 45, By the helical splines 32 and 33, the inner cylinder part 20 (camshaft 2) rotates with respect to the outer cylinder part 10 (sprocket body 12), and its phase changes. The rotating drum 44 is held at a position where the transmitted braking force and the spring force of the torsion coil spring 46 are balanced (position where the inner cylinder portion 20 has a predetermined phase difference with respect to the outer cylinder portion 10).

  On the other hand, when the electromagnetic clutch 42 is turned OFF, the braking force is not transmitted to the rotating drum 44, so that the intermediate member 30 on which only the spring force of the coil spring 46 acts is moved backward by the square screw portions 31 and 45 (left direction in FIG. 1). And the inner cylinder portion 20 (camshaft 2) rotates in the forward direction or the reverse direction with respect to the outer cylinder portion 10 (sprocket body 12) during this time, and the phase difference disappears. .

  A flange 24 is provided around the outer peripheral surface of the inner cylinder portion 20 (journal surface with the sprocket main body 12), while the flange 24 is engaged with the inner peripheral surface of the outer cylinder portion 10 (sprocket main body 12). A flange engaging groove 13A is provided around the friction engaging member 51 and 55 between the side surface of the flange 24 and the side surface of the flange engaging groove 13A. Thereby, the friction torque of the relative sliding part between the outer cylinder part 10 and the inner cylinder part 20 is increased, and the helical spline engaging parts 23, 32 between the intermediate member 30, the outer cylinder part 10 and the inner cylinder part 20, 33 and 17 and the generation of the hitting sound that the tooth portions of the square screw portions 31 and 45 collide with each other are suppressed.

As shown in FIGS. 3 to 5, the electromagnetic clutch 42 is formed in a cross-sectionally U-shaped annular shape and opened toward the disk surface 44 a of the rotating drum 44, and is accommodated in the clutch case 60. The electromagnetic coil 62 is configured. The electromagnetic coil 62 is fixed by a resin mold in an annular groove 65 between the inner peripheral wall 63 and the outer peripheral wall 64 of the clutch case 60.

A plurality of pins 68 project from the back side of the clutch case 60 along the circumferential direction thereof. Each pin 68 is engaged with the hole 8b on the cover 8 side. That is, the clutch case 60 is fixed to the cover 8 while being prevented from rotating in the circumferential direction, and is slidable in the axial direction of the camshaft 2 but is restrained so as not to move in the circumferential direction.

  At this time, in the clutch case 60, the end surface 63a of the inner peripheral wall 63 and the end surface 64a of the outer peripheral wall 64 are formed as opposing surfaces opposite to the disk surface 44a of the rotating drum 44, respectively. For example, an oil film having a thickness of 1 μm or less is formed between the outer peripheral wall 64 and the end surface 64a of the outer peripheral wall 64 and the disk surface 44a.

  That is, a plurality of, for example, 90 grooves 66 and 67 as oil passages are formed on the end surface 63a of the inner peripheral wall 63 and the end surface 64a of the outer peripheral wall 64, respectively. The grooves 66 and 67 are arranged at equal intervals every 4 ° in the circumferential direction of the end surface 63 a of the inner peripheral wall 63 and the end surface 64 a of the outer peripheral wall 64, and are formed along the radial direction of the clutch case 60.

As shown in FIG. 6, each of the grooves 66 and 67 has a substantially semicircular cross section and is formed with a width of 0.5 mm and a depth of 0.15 mm. Engine oil is constantly supplied.

Specifically, as shown in FIG. 1, oil that communicates with the oil passage 70 in the camshaft 2 and communicates with the space between the clutch case 60 and the rotating drum 44, on the radially inner side of the clutch case 60. A reservoir 74 is defined by the cover 8. Engine oil is pumped to the oil passage 70 in the camshaft 2 by the pump P through the oil port of the journal bearing 73 of the camshaft 2 and the side hole 73a of the camshaft 2.

The engine oil fed to the oil passage 70 is introduced into the oil reservoir 74 through the side hole 73b. When the electromagnetic clutch 42 is not energized, the engine oil in the oil reservoir 74 is discharged through a gap between the disk surface 44a of the rotating drum 44 and the clutch case 60, and is rotated through the oil outlet hole 80. 44 is led to the front side.

On the other hand, when the electromagnetic clutch 42 is energized, the disk surface 44 a of the rotary drum 44 and the clutch case 60 are close to each other, so that the engine oil in the oil reservoir 74 is formed on the end surface 63 a of the inner peripheral wall 63 of the clutch case 60. The oil is discharged through the groove 66 and the groove 67 formed in the end face 64 a of the outer peripheral wall 64, and led out to the front side of the rotating drum 44 through the oil lead-out hole 80.

For this reason, when the electromagnetic clutch 42 is de-energized and energized, the disk surface 44a of the rotating drum 44 and the end surfaces 63a and 64a of the clutch case 60 are effectively cooled by the engine oil.

Further, when engine oil is supplied from the oil reservoir 74 to the grooves 66 and 67, the groove 66 formed on the end surface 63 a of the inner peripheral wall 63 of the clutch case 60 and the disk surface 44 a of the rotary drum 44 and the outer peripheral wall. Between the groove 67 formed on the end face 64a of 64 and the disk surface 44a of the rotary drum 44, an oil film is formed over the grooves 66 and 67 and the periphery thereof.

  Thereby, the transmission of torque between the rotating drum 44 and the clutch case 60 can be executed through the grooves 66 and 67 and the oil film formed around the grooves 66 and 67.

According to the present embodiment, torque transmission between the rotary drum 44 and the clutch case 60 is performed through the grooves 66 and 67 and the oil film formed around the grooves 66 and 67. A high μ (friction coefficient) can be obtained without attaching a fiber friction material between the drums 44.

Further, according to the present embodiment, the following effects can be obtained.
(1) Since no friction material is mounted in the annular groove 65 of the clutch case 60, it is possible to prevent a decrease in μ due to clogging of the friction material.
(2) By eliminating the need for a friction material, the number of parts can be reduced and costs can be reduced.
(3) Even if the rotating drum 44 is made of an alloy and the clutch case 60 is made of soft iron, it is possible to suppress the wear of the clutch case 60 by setting the difference in surface hardness between each other to a certain value. it can.

  Next, a second embodiment of the present invention will be described with reference to FIG. In the present embodiment, a gap S as an air gap (AG) is formed between the end surface 63a of the inner peripheral wall 63 of the clutch case 60 and the disk surface 44a of the rotary drum 44, and the other configuration is the first embodiment. Similar to the example.

  According to the present embodiment, the transmission of torque between the rotary drum 44 and the clutch case 60 is performed via the grooves 67 and the oil film formed around the grooves 67. Therefore, the clutch case 60 and the rotary drum 44 are transmitted. High μ (friction coefficient) can be obtained without interposing a fiber friction material therebetween.

Further, according to the present embodiment, the same effects as those of the first embodiment can be obtained, and the air gap caused by the initial familiarity between the rotating drum 44 and the clutch case 60, that is, the so-called initial familiarity between metals, is reduced, and suction is performed. By increasing the force, it is possible to supplement the initial μ decrease (torque decrease).

Furthermore, according to the present embodiment, the rigidity of the clutch case 60 can be sufficiently increased, so that the adjustment and measurement of the air gap can be performed in a stable state.

Next, a third embodiment of the present invention will be described with reference to FIG. In the present embodiment, the end face 64a of the outer peripheral wall 64 of the clutch case 60 is formed in a tapered shape, and a groove 67 (not shown) is formed in the tapered end face 64a. Other configurations are the same as in the second embodiment. It is the same.

According to the present embodiment, torque transmission between the rotary drum 44 and the clutch case 60 is performed via the grooves 67 and the oil film formed around the grooves 67. There is an effect.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. In this embodiment, a groove 69 that is inclined with respect to an imaginary line perpendicular to the axis of the inner cylinder portion 20 is formed on the end face 64a of the outer peripheral wall 64 of the clutch case 60 as an oil flow. The same as in the second embodiment.

According to the present embodiment, torque transmission between the rotary drum 44 and the clutch case 60 is executed via the grooves 69 and the oil film formed around the grooves 69, so that the same as in the second embodiment. There is an effect.

Next, a fifth embodiment of the present invention will be described with reference to FIG. In this embodiment, the opening side end of the outer peripheral wall 64 of the clutch case 60 is divided into two steps to form a step 76, and a groove 67 (not shown) is formed as an oil flow in the end surface 76a of the step 76. The other configuration is the same as that of the second embodiment.

According to the present embodiment, torque transmission between the rotary drum 44 and the clutch case 60 is performed via the grooves 67 and the oil film formed around the grooves 67. There is an effect.

Further, according to the present embodiment, the opening side end portion of the outer peripheral wall 64 of the clutch case 60 is divided into two steps to form the step portion 76, and the groove 67 is formed in the end surface 76a of the step portion 76. The degree of freedom of the width (diameter length) of 76 can be increased, and the suction force can be easily controlled.

A sixth embodiment of the present invention will be described with reference to FIG. In the present embodiment, an annular tapered portion 77 is formed at the opening end of the outer peripheral wall 64 of the clutch case 60, and an annular tapered portion 78 facing the tapered portion 77 on the disk surface 44 a of the rotating drum 44. The groove 67 (not shown) is formed as an oil flow on the surface of the tapered portion 77, and the other configuration is the same as that of the second embodiment.

According to the present embodiment, torque transmission between the rotary drum 44 and the clutch case 60 is performed via the grooves 67 and the oil film formed around the grooves 67. There is an effect.

Further, according to the present embodiment, torque is transmitted between the rotary drum 44 and the clutch case 60 via the oil film formed between the taper portion 77 and the taper portion 78, so that the shaft of the electromagnetic clutch 42 is The torque can be supplemented by increasing the suction force in the direction.

In each embodiment, the clutch case 60 is formed with the grooves 66, 67, 69. However, even if a plurality of grooves are formed on the disk surface 44a of the rotary drum 44, the rotary drum 44 / clutch case is formed. The transmission of torque between 60 can be executed through each groove of the disk surface 44a and an oil film formed around the groove.

Claims (2)

An outer cylinder part to which rotation of the crankshaft of the engine is transmitted, an inner cylinder part connected to a camshaft that is rotatable relative to the outer cylinder part and opens and closes an intake valve or an exhaust valve of the engine; and the outer cylinder part; An intermediate member disposed between the inner tube portion and transmitting the rotational force of the outer tube portion to the inner tube portion, and moving the intermediate member in the axial direction; In the engine phase varying device for causing relative rotation between the inner cylinder portions to change the opening / closing timing of the intake valve or the exhaust valve,
An annular rotating drum arranged around the inner cylinder portion and connected to the intermediate member, and an electromagnetic clutch for controlling a braking force against the rotating drum according to an operating state of the engine,
The electromagnetic clutch is
An annular clutch case disposed opposite to the rotating drum, and an electromagnetic coil that generates a braking force against the rotating drum by moving the clutch case toward the rotating drum when energized,
A groove for forming an engine oil passage is formed on at least one of the facing surface of the rotating drum facing the clutch case or the facing surface of the clutch case facing the rotating drum, and the rotating drum An engine phase varying device, wherein torque is transmitted to and from the clutch case via the groove and an oil film formed around the groove. The phase varying apparatus for an engine according to claim 1,
The annular clutch case has a U-shaped cross section, and the electromagnetic coil is housed in an annular groove surrounded by an inner peripheral wall and an outer peripheral wall, and the outer peripheral wall faces the rotating drum. The groove is formed, a gap is formed between the inner peripheral wall and the rotary drum, and the transmission of torque between the rotary drum and the clutch case is transmitted to the groove formed on the outer peripheral wall and An engine phase varying device characterized by being executed through an oil film formed around the periphery.

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