JP2005180398A - Electromagnetic brake cooling structure of phase variable device in engine for automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic brake cooling structure of a phase variable device in an engine for automobile capable of effectively suppressing an increase in temperature of the surface of a friction material by leading an engine oil in a clearance on the rear side of a friction material holding plate in a clutch case to cool the rear side of the friction material. <P>SOLUTION: This phase variable device varies the phase of a camshaft 2 in association with the delay of rotation of a rotary drum44 relative to a sprocket body 12 caused by a braking force. An electromagnetic brake means 40 is so formed that the friction material holding plate 64 is fixed to the front opening part of the annular clutch case 60 of U-shape in cross section which stores an electromagnetic coil 62. A cutout 61a is formed at the inner peripheral wall front edge part of the clutch case 60 to activate the supply and discharge of oil to and from the sliding surface of the friction material 66 against the rotary drum 44. The cooling effect of the friction material 66 is improved with a cooling structure wherein the cutout 61a is deepened and the oil is circulated into the rear space S1 of the friction material holding plate 64 in the clutch case 60. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a phase variable device in an automobile engine that applies a braking force to a rotating drum by an electromagnetic brake means to change a rotational phase of a camshaft with respect to a sprocket to change a valve opening / closing timing. The present invention relates to a cooling structure in which engine oil is circulated and cooled by electromagnetic brake means for applying a braking force to a rotating drum of the apparatus.

  As this type of prior art, as shown in the following Patent Document 1 (see FIG. 11), a drive member (sprocket) 12 to which a driving force of a crankshaft of an engine is transmitted and a camshaft 2 constituting a valve mechanism are provided. The phase between the drive member 12 and the camshaft 2 is changed by moving the intermediate member 30 with the inner and outer helical splines interposed in the axial direction in the axial direction. That is, the braking force is applied to the rotating drum 44 rotatably supported on the camshaft 2 by the electromagnetic brake means 40 that is prevented from rotating in the circumferential direction, whereby the rotating drum 44 is delayed with respect to the drive member 12. As a result, the intermediate member 30 moves in the axial direction, the camshaft 2 rotates relative to the drive member 12, and the phase between the two members 12 changes. The device is disposed inside the engine room and is driven in an engine oil atmosphere.

  The electromagnetic brake means 40 includes a clutch case 60 having a U-shaped cross section that houses the electromagnetic coil 62, a holding plate 64 that closes the opening of the clutch case 60, and a friction material 66 that is bonded to the holding plate 64. It is prepared for. In the relative sliding surface between the friction material 66 of the clutch case 60 and the rotary drum 44, when the sliding surface temperature becomes high due to the sliding heat, an antioxidant or friction modifier dispersed in the engine oil, The surface of the friction material 66 that is generally composed of a porous material is clogged by the reaction product of additives such as a cleaning dispersant and the insoluble matter in the oil, and friction generated between the friction material 66 and the rotating drum 44. Torque can be reduced.

  For this reason, in order to suppress the high temperature of the relative sliding surface between the friction material 66 of the clutch case 60 and the rotary drum 44, the radial direction of the clutch case 60 is provided via the oil passage 70 and the side hole 73b in the camshaft 2. Engine oil is supplied to the oil reservoir 74 located inward, and the engine oil in the oil reservoir 74 is interposed between the friction material 66 and the rotary drum 44 through a notch 61 a provided at the front edge of the inner peripheral wall of the clutch case 60. The relative sliding surface is supplied to the relative sliding surface to cool the relative sliding surface.

Furthermore, by providing a notch 61b for leading the oil on the relative sliding surface side radially outward at the front edge of the outer peripheral wall of the clutch case 60, the oil supply / discharge speed of the oil on the relative sliding surface side is increased, The cooling effect of the relative sliding surface is increased. Reference numeral 80 denotes an oil outlet hole 80 provided near the inner peripheral wall of the clutch case in the rotary drum 44. When engine oil is led out from the oil outlet hole 80, heat on the rotary drum 44 side is transferred to the oil outlet hole 80. Since heat is radiated from the inner peripheral surface to the engine oil, the cooling of the rotating drum 44 (relative sliding surface) is effective.
JP 2002-371814 A

  The above-described conventional electromagnetic brake cooling structure can be satisfied for cooling the sliding surface of the friction material. However, to increase the cooling effect, the number of notches 61a for introducing oil and the number of notches 61b for extracting oil may be increased. However, as the number of notches 61a and 61b increases, the number of notches 61a and 61b increases. There is a problem in that the area of the front edge of the inner and outer peripheral walls of the clutch case 60 serving as a path of magnetic lines of force is reduced, and the braking force of the electromagnetic brake is reduced. In the electromagnetic brake cooling structure by providing the notches 61a and 61b, There is a limit. For this reason, in order to obtain a cooling structure that is effective in a higher temperature environment or the like, there is a demand for a novel measure that is superior by suppressing the increase in the temperature of the relative sliding surface of the friction material.

  Therefore, the inventor has considered a new structure from the viewpoint of whether heat can be radiated from the back side of the friction material 66 as compared to the conventional structure in which heat is radiated only from the sliding surface side of the friction material 66. That is, the friction material 66 is joined and integrated with the friction material holding plate 64 and is fixed inside the opening of the clutch case 60. The clutch case 60 contains a resin-molded electromagnetic coil 62. An annular gap S <b> 1 is formed between the resin mold part 62 a and the friction material holding plate 64. The inventors pay attention to the gap S1 in the clutch case 60, and if the depth of the notch 61a for introducing oil is increased, the engine oil can be introduced into the gap S1, and the introduced engine oil retains the friction material. It was thought that the heat dissipation was improved by contacting the back surface of the plate 64. Further, since the inside of the clutch case 60 is sealed with a resin mold, even if the engine oil is introduced into the gap S1, the engine oil is unlikely to enter the electromagnetic coil 62. Further, even if the sealing of the oil by the resin mold is incomplete, there is a possibility that the engine oil enters the power supply cord 100 led out from the clutch case 60 and travels through the power supply cord 100 to ooze out to the outside. Even in such a case, by providing an oil sealing connector in the middle of the power supply cord 100, the engine oil can be reliably prevented from leaching to the outside, so that the engine oil is introduced into the gap S1 in the clutch case 60. But there is no problem.

  And as a result of making a prototype and repeating experiments to confirm the effect, it was confirmed that it was effective in cooling the relative sliding surface of the friction material, so the present invention was proposed. is there.

  The present invention has been made on the basis of the problems of the prior art described above and the knowledge of the inventor described above, and the object thereof is an annular gap on the back side of the friction material holding plate in which the friction material is joined and integrated. By introducing engine oil into the engine and increasing the amount of heat released from the friction material to the engine oil, the electromagnetic force of the phase variable device in an automobile engine that is effective in suppressing the high temperature of the relative sliding surface between the friction material and the rotating drum It is to provide a brake cooling structure.

In order to achieve the above object, in claim 1, a camshaft constituting a valve operating mechanism is coaxially arranged relative to an annular sprocket to which a driving force of a crankshaft is transmitted, and is arranged to be relatively rotatable. A rotating drum is rotatably supported on the shaft, and an electromagnetic brake means for applying a braking force to the rotating drum is provided at a position facing the rotating drum in the axial direction, and the sprocket generated in the rotating drum by the braking force In a phase varying device in an automobile engine in which the phase between the sprocket and the camshaft changes in conjunction with a rotational delay with respect to
The electromagnetic brake means includes a clutch case having a U-shaped cross section that opens toward the disk surface of the rotating drum and is prevented from rotating in the circumferential direction, an electromagnetic coil housed in the clutch case, and the clutch A friction material holding plate fixed to the inside of the opening of the case, and a flat friction material bonded to the friction material holding plate and whose surface slightly protrudes from the front edge of the inner and outer peripheral wall of the clutch case,
An oil sump that communicates with the oil passage of the camshaft and communicates with the inner peripheral side of the relative sliding portion between the clutch case and the rotating drum is provided on the radially inner side of the clutch case. An electromagnetic brake cooling structure for a phase variable device in an automobile engine provided with a notch for oil introduction that guides the engine oil in the oil reservoir to the relative sliding surface of the friction material and the rotating drum at the front edge of the inner peripheral wall Because
The notch for introducing the oil is formed deeper than the bottom surface of the friction material holding plate, and the engine oil in the oil reservoir is exposed to the bottom surface of the friction material holding plate in the clutch case through the notch. Configured to guide.

  In addition, due to the braking force applied by the electromagnetic brake means, a rotation delay with respect to the sprocket occurs in the rotating drum, and the intermediate member moves in the axial direction in conjunction with this rotation delay, and the camshaft rotates with respect to the sprocket ( As a configuration in which the phase between the sprocket and the camshaft changes, for example, as shown in the embodiment of the present invention, the sprocket (outer cylinder portion 10) and the camshaft (inner cylinder portion 20) are screwed into the rotary drum 44. ), An intermediate member 30 that engages with the inner and outer helical splines is interposed between the sprocket (outer cylinder portion 10) and the camshaft (inner cylinder portion 20) (see FIGS. 1 and 2).

  (Operation) The sprocket to which the driving force of the crankshaft of the engine is transmitted and the camshaft constituting the valve mechanism are configured to rotate together, and the sprocket and the camshaft rotate in synchronization. When a braking force is applied to the rotating drum by the electromagnetic brake means, a rotation delay with respect to the sprocket is generated in the rotating drum, and the phase of the camshaft with respect to the sprocket changes in conjunction with the rotation delay of the rotating drum.

  The relative sliding surface between the friction material of the clutch case and the rotating drum is provided at the front edge of the inner peripheral wall of the clutch case through an oil passage provided in the camshaft and an oil reservoir provided on the inner side in the radial direction of the clutch case. New engine oil is introduced from the oil introduction notch, and the engine oil that has taken heat away from the friction material and disk surface at the relative sliding surface between the friction material and the rotating drum is the front edge of the outer peripheral wall of the clutch case. And is led out from the gap between the rotating drums. Since the notch for oil introduction is provided at the front edge of the inner peripheral wall of the clutch case, the engine oil supply and discharge activities on the relative sliding surface between the friction material and the rotating drum become active, and the temperature of the relative sliding surface is increased. High temperature is suppressed. Furthermore, the engine oil in the oil reservoir is introduced into a gap on the opening side in the clutch case (an annular gap extending along the back surface of the friction material holding plate) via a notch for oil introduction, and the friction material After removing heat from the friction material holding plate by coming into contact with the holding plate, the oil material is dropped (derived) by its own weight from the notch for oil introduction and returns to the oil reservoir. That is, when the rotating drum rotates, an engine is formed by an oil reservoir, a notch for oil introduction, and a gap on the opening side in the clutch case (an annular gap extending along the back surface of the friction material holding plate). Since the oil circulation passage is formed and the back surface side of the friction material holding plate is cooled, the cooling effect of the relative sliding surface between the friction material and the rotating drum is increased accordingly.

  According to a second aspect of the present invention, in the electromagnetic brake cooling structure of the phase varying device in the automobile engine according to the first aspect, the engine between the friction material and the relative sliding surface of the rotary drum is provided at the front edge of the outer peripheral wall of the clutch case. An oil lead-out notch for leading out the oil is provided, and the oil lead-out notch is also formed deeper than the bottom surface of the friction material holding plate so that the engine oil in the clutch case has the notch. Via the clutch case.

  (Effect) The amount of oil derived from the engine oil between the friction material and the rotating drum relative to the sliding surface is increased by the amount of the oil lead-out notch. Engine oil supply and discharge activities become more active, and the temperature of the relative sliding surface is further prevented from increasing.

  The engine oil introduced into the annular gap on the back side of the friction material holding plate in the clutch case through the oil introduction notch is also led out from the oil lead-out notch, so the circle on the back side of the friction material holding plate The engine oil supply / discharge activity in the annular gap becomes active, the amount of heat released from the friction material holding plate to the engine oil is increased, and the temperature rise of the relative sliding surface is further suppressed.

  According to a third aspect of the present invention, in the electromagnetic brake cooling structure of the phase varying device in the automobile engine according to the second aspect, the notch for introducing oil and the notch for extracting oil are offset in the circumferential direction of the clutch case. Configured to do.

  (Operation) Since the notch for oil introduction and the notch for oil delivery do not face each other, the annular notch between the friction material and the rotating drum and the back side of the friction material holding plate from the oil introduction notch The engine oil introduced into the gaps takes a long time to be drawn out from the oil lead-out notch (the flow of engine oil in the annular gap on the back side of the friction material holding plate becomes slow). The amount of heat released to the engine oil in the relative sliding surface and the annular gap increases, and the cooling effect of the relative sliding surface between the friction material and the rotating drum increases.

  In claim 4, in the electromagnetic brake cooling structure of the phase varying device in the automobile engine according to any one of claims 1 to 3, on the radially inner side of the disk surface of the rotating drum facing the friction material, An oil lead-out hole for leading out a part of the engine oil introduced into the relative sliding portion between the friction material and the rotary drum is provided by the notch for introducing oil.

  (Operation) When engine oil introduced into the relative sliding portion between the friction material and the rotating drum by the oil introduction notch passes through an oil outlet hole provided so as to penetrate the rotating drum in the axial direction. Since the heat on the rotating drum side is taken away, the cooling effect on the relative sliding surface between the friction material and the rotating drum is increased accordingly.

  According to the first aspect, since heat is radiated to the engine oil on both the front and back sides of the friction material, the cooling effect of the relative sliding surface of the friction material by the circulating engine oil is improved, and the friction material when the electromagnetic brake is operated Good braking characteristics (braking performance) between the rotating drum and the rotating drum are maintained.

  According to the second aspect of the present invention, the engine oil is actively circulated in the relative sliding surface between the friction material and the rotating drum and the annular gap on the back side of the friction material holding plate, and the cooling of the relative sliding surface by the circulating engine oil is performed. The effect is improved, and good braking characteristics (braking performance) between the friction material and the rotating drum when the electromagnetic brake is operated are maintained.

  According to the third aspect, the flow of the engine oil in the relative sliding surface between the friction material and the rotating drum and the annular gap on the back side of the friction material holding plate becomes slow, and the cooling of the relative sliding surface by the circulating engine oil is performed. The effect is further improved, and good braking characteristics (braking performance) between the friction material and the rotating drum when the electromagnetic brake is operated are maintained.

  According to the fourth aspect of the present invention, the cooling effect of the relative sliding surface by the circulating engine oil is further improved by the amount of heat radiation to the engine oil due to the provision of the oil outlet hole, and the electromagnetic brake is activated. Good braking characteristics (braking performance) between the friction material and the rotating drum are maintained.

  Next, embodiments of the present invention will be described based on examples.

  1 to 6 show a first embodiment of a phase varying device according to the present invention, and FIG. 1 is a longitudinal sectional view of the phase varying device in an automobile engine according to the first embodiment of the present invention. Is a perspective view showing the internal structure of the apparatus, FIG. 3 is a perspective view of an electromagnetic clutch constituting the main part of the electromagnetic brake means, FIG. 4 is a front view of the electromagnetic clutch, and FIGS. FIG. 6 is an enlarged cross-sectional view of a relative sliding portion between a material and a rotary drum, where (a) is a cross-sectional view at a notch position for introducing oil, (b) is a cross-sectional view at a caulking portion position, and FIG. 6 is a perspective view of the rotary drum. It is.

  In these figures, the phase variable device shown in this embodiment is used in a form integrated with the engine, and the camshaft rotates the crankshaft so that the intake / exhaust valve opens and closes in synchronization with the rotation of the crankshaft. This is a device that changes the opening and closing timing of the intake and exhaust valves of the engine according to the operating conditions such as engine load and rotation speed. This device is a sprocket that transmits the driving force of the crankshaft of the engine. A certain annular outer cylindrical portion 10, a driven annular inner cylindrical portion 20 which is disposed coaxially with the outer cylindrical portion 10 and is rotatable relative to the outer cylindrical portion 10 and which constitutes a part of the camshaft 2; The outer cylinder part 10 and the inner cylinder part 20 are respectively helically spline-engaged and interposed between the outer cylinder part 10 and the inner cylinder part 20 and moved in the axial direction to move the inner cylinder part 20 relative to the outer cylinder part 10. An intermediate member 30 to change the phase, provided on the cam shaft 2 non-disposed side of the inner cylinder portion 20 is configured to include an electromagnetic brake means 40 for moving the intermediate member 30 in the axial direction. Reference numeral 8 denotes an engine case (phase variable device cover), and the engine and the device are used in an engine oil atmosphere.

  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. Reference numeral 13a is a large-diameter concave part on the opening side of the concave part 13, and reference numeral 13b is a small-diameter concave part on the heel side of the concave part 13, between the outer peripheral edge of the flange 24 on the inner cylinder part 20 side to be described later. A stepped portion 13c that directly faces is provided. 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.

  Reference numerals 32 and 33 are male and female helical splines provided on the inner and outer peripheral surfaces of the intermediate member 30, reference numeral 23 is a male helical spline provided on the outer peripheral surface of the inner cylinder portion 20, and reference numeral 17 is an inner portion of the spline case 16. It is the female helical spline provided in the surrounding surface. The inner and outer splines 32 and 33 of the intermediate member 30 are reverse helical splines, and the phase of the inner cylinder portion 20 can be greatly changed with respect to the outer cylinder portion 10 by a slight movement of the intermediate member 30 in the axial direction. it can. Reference numeral 31 denotes a male thread portion 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 engine case 8 and the bearing 22, and the male screw portion 31 of the intermediate member 30 is screwed into the electromagnetic clutch. The rotating drum 44 to which the braking force of 42 is transmitted, and the torsion coil spring 46 interposed between the rotating drum 44 and the outer cylinder portion 10 in the axial direction are configured. Reference numeral 45 denotes a female square screw portion 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, and when no braking force acts on 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.

  Then, by controlling the 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, 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 cylinder part 20 rotates integrally with no phase difference. When the electromagnetic clutch 42 is turned on, the electromagnetic clutch 42 slides in the right direction in FIG. 1 and is attracted to the rotating drum 44, whereby a 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). The inner cylinder portion 20 (camshaft 2) rotates in the opposite direction with respect to the outer cylinder portion 10 (sprocket body 12), and the phase difference disappears.

  Further, a flange 24 is provided around the outer peripheral surface (sliding surface with the sprocket main body 12) of the inner cylindrical portion 20, while the flange 24 is engaged with the inner peripheral surface of the outer cylindrical portion 10 (sprocket main body 12). A mating flange engaging groove 13A is provided around, and friction torque adding members 51 and 55 are interposed between the side surface of the flange 24 and the side surface of the flange engaging groove 13A. The friction torque of the relative sliding portion is increased, and the hitting sound that the teeth of the helical spline engaging portions 23, 32, 33, and 17 between the intermediate member 30 and the outer cylindrical portion 10 and the inner cylindrical portion 20 collide with each other is generated. It is suppressed.

  Next, the structure of the electromagnetic clutch 42 constituting the electromagnetic brake means 40 and the cooling structure of the relative sliding surface between the friction material 66 provided on the surface of the electromagnetic clutch 42 and the rotary drum 44 will be described.

  As shown in FIGS. 3 to 5, the electromagnetic clutch 42 includes a clutch case 60 having a U-shaped cross section that opens toward the disk surface of the rotating drum 44 and is prevented from rotating in the circumferential direction. The accommodated electromagnetic coil 62, a metal (non-magnetic metal stainless steel) friction material holding plate 64 fixed inside the opening of the clutch case 60, and the friction material holding plate 64 are bonded to each other by bonding. The surface of the clutch case 60 includes a flat friction material 66 that slightly protrudes from the front edge portions of the inner and outer peripheral walls 60a and 60b. Reference numeral 68 designates pins protruding in a plurality of positions in the circumferential direction on the back side of the clutch case 60. The pins 68 engage with the holes 8a on the engine case 8 side so that the clutch case 60 can slide in the axial direction. It is restrained so that it cannot move in the circumferential direction.

That is, the electromagnetic coil 62 is fixed in the clutch case 60 by a resin mold, and the friction material holding plate 64 in which the friction material 66 is integrated is placed on the stepped portion 60c inside the opening of the clutch case 60. Three portions of the inner and outer circumferences of the holding plate 64 that are equally divided in the circumferential direction are fixed to the inner and outer peripheral walls 60a and 60b of the clutch case by caulking.
In addition, reference numeral 60d shown in FIGS. 3 and 4 indicates a caulking portion. Between the resin mold part 62a in the clutch case 60 and the friction material holding plate 64, an annular gap (space) S1 extending along the friction material holding plate 64 is provided. Since engine oil is actively introduced into the gap S1, the power supply cord 100 led out from the clutch case 60 and the clutch case is provided with oil sealing means. That is, the periphery of the electromagnetic coil 62 in the clutch case 60 is resin-molded, and there is no possibility that engine oil will enter the electromagnetic coil 62. Further, even if the sealing of the oil by the resin mold is incomplete, there is a possibility that the engine oil enters the power supply cord 100 led out from the clutch case 60 and travels through the power supply cord 100 to ooze out to the outside. Even in such a case, by providing a connector (not shown) for oil sealing in the middle of the power supply cord 100, leaching of the engine oil to the outside is reliably prevented.

  The radial width of the friction material 66 is formed to be slightly smaller than the radial width of the friction material holding plate 64 (the inner diameter of the friction material 66 is slightly larger than the inner diameter of the friction material holding plate 64). The outer diameter of 66 is formed to be slightly smaller than the outer diameter of the friction material holding plate 64), whereby a ring-shaped groove 63 a serving as an oil passage is formed between the inner and outer peripheral walls 60 a, 60 b of the clutch case and the friction material 66. , 63b. Note that the means for fixing the friction material holding plate 64 to the opening of the clutch case 60 is not limited to the above-described caulking, and may be any appropriate fixing means such as adhesion, fitting or the like.

  The friction material 66 is used to generate a frictional force (braking force) by approaching the disk surface of the rotating drum 44 when the electromagnetic clutch 42 is turned on. The thickness of the papermaking base impregnated with a thermosetting resin. The surface of the clutch case 60 protrudes from the front edge portions of the inner and outer peripheral walls 60a and 60b by 50 μm.

  Further, the engine oil is always supplied to the relative sliding surface between the friction material 66 of the electromagnetic clutch 42 and the rotary drum 44, and the increase of the sliding surface temperature of both 66 and 44 is suppressed.

  That is, on the radially inner side of the clutch case 60, as shown in FIG. 1, it communicates with the oil passage 70 in the camshaft 2 and on the inner peripheral side of the relative sliding portion between the clutch case 60 and the rotating drum 44. A communicating oil reservoir 74 is defined by the engine case 8, and engine oil is passed through the oil passage 70 in the camshaft 2 via the oil port of the journal bearing 73 of the camshaft 2 and the side hole 73 a of the camshaft 2. Pumped by a pump P. Reference numeral 73 b is a side hole provided in the camshaft 2 and communicating with the oil passage 70 and the oil reservoir 74. The front edge of the inner peripheral wall 60a of the clutch case is provided with an oil introduction notch 61a for introducing engine oil to the relative sliding surface between the friction material 66 and the rotary drum 44, while the outer periphery of the clutch case is The front edge of the wall 60b is provided with an oil lead-out notch 61b that leads the engine oil of the relative sliding surface between the friction material 66 and the rotary drum 44 outward.

  An oil passage 70 provided in the camshaft 2, an oil reservoir 74 between the engine case 8 and the rotating drum 44 (bearing 22), and a relative sliding surface between the friction material 66 and the rotating drum 44 of the clutch case 60 and Engine oil is introduced through a notch 61a provided at the front edge of the inner peripheral wall 60a of the clutch case to cool the relative sliding surfaces of the friction material 66 and the rotary drum 44, and between the friction material 66 and the rotary drum 44. The engine oil that has been used for cooling the relative sliding surface is positively discharged radially outwardly through an oil outlet notch 61b provided at the front edge of the outer peripheral wall 60b of the clutch case 60. Therefore, the supply / discharge speed of the engine oil to the relative sliding surface between the friction material 66 and the rotating drum 44 is high, and the circulation of oil in the relative sliding portion between the friction material 66 and the rotating drum 44 becomes active. The sliding heat generated on the relative sliding surface between the friction material 66 and the rotating drum 44 is radiated to the circulating engine oil, and the relative sliding surface between the friction material 66 and the rotating drum 44 is effectively cooled.

  Further, as shown in FIGS. 3 and 4, a windmill type oil groove 67 extending from the inner periphery side to the outer periphery side is provided on the surface of the friction material 66, so that a notch 61a for oil introduction and an oil lead-out oil are provided. The notch 61b communicates with the ring-shaped gap 63a, the windmill-type oil groove 67, and the ring-shaped gap 63b. For this reason, the engine oil introduced radially inward of the relative sliding portion between the friction material 66 and the rotary drum 44 flows smoothly along the oil groove 67 on the surface of the friction material 66, so that a notch for oil derivation is obtained. Since it is derived from 61b, the entire surface of the friction material 66 is uniformly cooled, the amount of oil derived and introduced is increased, and the circulation of oil is increased accordingly, and the cooling effect is further improved.

  Further, as shown in FIGS. 5 and 6, oil guide holes 80 are provided at eight positions equally divided in the circumferential direction at a position facing the friction material 66 on the disk surface of the rotating drum 44 and near the inner peripheral wall 60 a of the clutch case. A part of the engine oil provided on the relative sliding surface between the friction material 66 and the rotating drum 44 is led to the front side of the rotating drum 44 so as to further enhance the cooling effect on the relative sliding surface. It has become.

  That is, when the engine oil is led out from the oil lead-out hole 80, the heat on the rotating drum 44 side is radiated from the inner peripheral surface of the oil lead-out hole 80 to the engine oil, which is effective for cooling the rotary drum 44. As a result, it acts to lower the surface temperature of the friction material 66.

Further, as shown in FIG. 5, the notch 61a for introducing oil and the notch 61b for extracting oil are formed deeper than the stepped portion 60c, which is the holding plate carrying surface, to hold the friction material in the clutch case 60. Engine oil is introduced into an annular gap (space) S1 on the back side of the plate 64. Reference numeral H inside and outside wall 60a of the clutch case 60, 60b before the edge to the stepped portion 60c depth, reference numeral _h 1, _{h 2} are notches 61a for introducing, step notch 61b for deriving The depth from the part 60c is shown. That is, the engine oil in the oil reservoir 74 is introduced into the annular gap (space) S1 from the notch 61a for introducing oil, and after partly depriving the heat by coming into contact with the friction material holding plate 64, a part of the oil It drops (derived) by its own weight from the notch 61a for introduction and returns to the oil reservoir 74. Further, part of the engine oil that has taken heat from the friction material holding plate 64 in the annular gap (space) S1 is led out radially outward from the oil lead-out notch 61b. As described above, the engine oil flows through the engine oil circulation passage formed by the notches 61a and 61b and the annular gap (space) S1, so that the friction material holding plate 60 is also cooled from the back side. As a result, it acts more effectively in reducing the surface temperature of the friction material 66.

  FIG. 9 shows the ratio of the surface temperature (vertical axis) of the friction material 66 with respect to the rotational speed (horizontal axis) of the engine of the cooling structure of this embodiment as a ratio to the conventional cooling structure (Patent Document 1) indicated by D. As shown, the temperature reduction rate of the friction material in the cooling structure of the present embodiment indicated by reference signs A1 to A4 is compared with the temperature reduction rate of the friction material in the conventional cooling structure (Patent Document 1) indicated by reference sign D of FIG. , You can see that it is excellent.

FIG. 10 shows the specifications of the notch 61a for introducing oil and the notch 61b for extracting oil in the embodiment of the present invention. In this figure, the notch 61a for introducing oil is indicated as “inside”, the notch 61b for extracting oil is indicated as “outside”, and the notches 61a and 61b of the conventional cooling structure (Patent Document 1) indicated by the symbol D are shown. The depths h ₁ and h ₂ are equal to the depth H from the front edge portion of the inner and outer peripheral walls of the clutch case 60 to the stepped portion 60c, whereas the cooling structure of the present embodiment indicated by reference numerals A1 to A4. Then, the depths h ₁ and h _{2 of the} notches 61a and 61b are H + 2 mm or H + 1.5 mm, and are formed to a depth exceeding the position of the stepped portion 60c. As the effect of reducing the friction material surface temperature, when the depths h ₁ and h ₂ of the notches 61a and 61b are set to H + 2 mm (reference A1), the temperature is about 2% at the maximum as compared with the conventional cooling structure. When the depths h ₁ and h ₂ of the notches 61a and 61b are set to D + 1.5 mm (reference numeral A1), there is a temperature reduction effect of 4 to 8%, and the depth of the notches 61a and 61b. When the depths h ₁ and h ₂ are H + 2 mm and H + 1.5 mm (reference A3) and the depths h ₁ and h _{2 of the} notches 61a and 61b are H + 1.5 mm and H + 2 mm (reference A4), respectively It can be seen that there is a 4-10% temperature reduction effect.

  FIG. 7 is a front view of the electromagnetic clutch constituting the main part of the electromagnetic brake means of the electromagnetic brake cooling structure according to the second embodiment of the present invention.

  In the above-described embodiment, the oil introduction notch 61a and the oil lead-out notch 61b provided at the front edge portion of the inner and outer peripheral walls of the clutch case 60 are positions corresponding to the circumferential direction (positions facing the radial direction). However, in this second embodiment, the notch 61a for introducing oil and the notch 61b for extracting oil are provided at positions shifted by 60 degrees in the circumferential direction. Others are the same as in the first embodiment described above, and a duplicate description thereof is omitted.

In the cooling structure of the second embodiment, as shown in FIG. 10, the depths h ₁ and h ₂ of the notches 61a and 61b are H + 1.2 mm, H, and H + 2 mm, H + 1.2 mm. When the reduction rate of the surface temperature of the friction material 66 was obtained, the results shown in FIG. As can be seen from FIG. 9, in the cooling structure of the second embodiment, the temperature is reduced by about 8 to about 15% as compared with the temperature reduction rate in the conventional cooling structure (Patent Document 1) indicated by symbol D in FIG. It turns out that there is an effect.

  This is because the notch 16a for introducing oil and the notch 16b for extracting oil are offset by 60 degrees in the circumferential direction so as not to face each other. The length of each engine oil flow passage in the annular gap S1 on the back side of the material holding plate 64 is increased, and the oil introduction notch 61a extends between the relative sliding surfaces of the friction material 66 and the rotary drum 44, and The engine oil introduced into the annular gap S1 on the back side of the friction material holding plate 64 takes a long time to be led out from the notch 61b for oil lead-out. And the amount of heat released to the engine oil (from the relative sliding surface and the friction material holding plate 60) flowing through the annular gap S1 increases, Cooling effect of Kosuzai surface is presumed to rise.

  FIG. 8 is a front view of the electromagnetic clutch constituting the main part of the electromagnetic brake means of the electromagnetic brake cooling structure according to the third embodiment of the present invention.

  In the first and second embodiments described above, a notch 61a for oil introduction is provided at the front edge of the inner peripheral wall of the clutch case 60, and a notch 61b for oil extraction is provided at the front edge of the outer peripheral wall of the clutch case 60. In this third embodiment, the notch 61a for oil introduction is provided at the front edge of the inner peripheral wall of the clutch case 60, but the front edge of the outer peripheral wall of the clutch case 60 is provided. Is not provided with an oil lead-out notch 61b. Others are the same as in the first embodiment described above, and a duplicate description thereof is omitted.

  In the cooling structure of this embodiment, as shown in FIG. 10, when the depth h of the notch 61a is set to H + 1.2 mm and H + 2 mm, the reduction rate of the surface temperature of the friction material 66 is obtained. , B2. As can be seen from FIG. 9, it can be seen that there is a temperature reduction effect of about 4 to about 10% as compared with the temperature reduction rate in the conventional cooling structure (Patent Document 1) indicated by symbol D in the figure.

  This is because the oil guide notch 61b is not provided at the front edge of the outer peripheral wall of the clutch case 60, so that the engine oil introduced between the relative sliding surfaces of the friction material 66 and the rotary drum 44 is On the other hand, the engine oil introduced into the annular gap S1 on the back side of the friction material holding plate 64 is not provided with the notch 61b for oil extraction. After contacting the holding plate 64 and taking heat away, it drops (derived) by its own weight from the notch 61a for oil introduction and returns to the oil reservoir 74, but the friction material holding plate is reduced by the amount of oil flow in the gap S1. It is surmised that the cooling effect on the back surface side of 64 is somewhat inferior to that of the second embodiment, and the temperature reduction rate is as indicated by reference numerals B1 and B2.

  In the above-described embodiment, the structure in which the oil outlet hole 80 for releasing the heat on the rotary drum 44 side is provided in the disk portion of the rotary drum 44 is shown, but the oil outlet hole 80 is not necessarily required.

  Further, in the above-described embodiment, the porous material in which the papermaking base material is impregnated with the thermosetting resin is shown as the friction material 66 provided on the front surface of the clutch case 60 that applies the brake to the rotating drum 44. Or you may make it comprise with the porous molded object which impregnated the thermosetting resin to the nonwoven fabric which consists of an aramid fiber, and the porous molded object which impregnated the thermosetting resin to the nonwoven fabric which consists of carbon fiber and an aramid fiber.

It is a longitudinal cross-sectional view of the phase variable apparatus in the engine for motor vehicles which is the 1st Example of this invention. It is a perspective view which shows the internal structure of the apparatus. It is a perspective view of the electromagnetic clutch which comprises the principal part of an electromagnetic brake means. It is a front view of the electromagnetic clutch. It is an expanded sectional view of the relative sliding part between a friction material and a rotating drum, (a) is sectional drawing in the notch position for oil introduction, (b) is sectional drawing in the crimping part position. It is a perspective view of a rotating drum. It is a front view of the rotating drum which is the principal part of the phase variable apparatus in the engine for motor vehicles which is the 2nd Example of this invention. It is a front view of the rotating drum which is the principal part of the phase variable apparatus in the engine for motor vehicles which is the 3rd Example of this invention. It is a figure which shows the reduction rate of the friction material surface temperature with respect to the rotation speed of an engine. FIG. 10 is a diagram showing a structure of an oil introduction notch and an oil lead-out notch provided on the front edge of the inner peripheral wall of the clutch case used for obtaining the temperature reduction rate characteristics shown in FIG. 9 in comparison with the conventional structure. It is a longitudinal cross-sectional view of the phase variable apparatus in the conventional automobile engine.

Explanation of symbols

2 Camshaft 2a Cam 8 Engine Case 8a Engine Case Side Hole Constructing Clutch Case Non-Rotating Means 10 Annular Outer Tube Portion as Sprocket 12 Sprocket Main Body 13 Recess 14 Inner Flange Plate 16 Spline Case 17, 32 Female Helical Spline 17, 33, 23, 32 Helical spline engaging portion 20 Annular inner tube portion 23, 33 male helical spline 30 constituting a part of the camshaft 30 Intermediate member 31, 45 Square screw portion 40 Electromagnetic brake means 42 Electromagnetic clutch 44 Rotation Drum 46 Torsion coil spring 60 Clutch case 60a Clutch case inner peripheral wall 60b Clutch case outer peripheral wall 60c Stepped portion 60d Caulking portion 61a Notch for introducing oil 61b Notch for extracting oil 62 Electromagnetic coil 62a Resin Mold part 64 Friction material holding plate S1 Annular gap (space) along the friction material holding plate in the clutch case
66 Flat friction material 67, 67a, 67b Oil groove on friction material surface 68 Clutch case side pin constituting clutch case detent means 70 Oil passage provided in camshaft 74 Radial inner side of clutch case Oil reservoir 80 Oil outlet hole provided in the disk part of the rotating drum 100 Cord for feeding power to the electromagnetic coil

Claims (4)

A camshaft constituting a valve operating mechanism is coaxially arranged relative to an annular sprocket to which the driving force of the crankshaft is transmitted, and is rotatably supported on the camshaft. An electromagnetic brake means for applying a braking force to the rotating drum is provided at a position directly facing the axial direction with respect to the sprocket and the camshaft in association with a rotation delay with respect to the sprocket generated in the rotating drum by the braking force. In the phase variable device in the automobile engine where the phase of
The electromagnetic brake means includes a clutch case having a U-shaped cross section that opens toward the disk surface of the rotating drum and is prevented from rotating in the circumferential direction, an electromagnetic coil housed in the clutch case, and the clutch A friction material holding plate fixed to the inside of the opening of the case, and a flat friction material which is joined and integrated with the friction material holding plate and whose surface slightly protrudes from the front edge of the inner and outer peripheral wall of the clutch case. Prepared,
An oil sump that communicates with the oil passage of the camshaft and communicates with the inner peripheral side of the relative sliding portion between the clutch case and the rotating drum is provided on the radially inner side of the clutch case. An electromagnetic brake for a phase varying device in an automobile engine provided with a notch for introducing oil that guides engine oil in the oil reservoir to a relative sliding surface between the friction material and the rotating drum at the front edge of the inner peripheral wall A cooling structure,
The oil introduction notch is formed deeper than the bottom surface of the friction material holding plate, and the engine oil in the oil reservoir faces the bottom surface of the friction material holding plate in the clutch case via the notch. An electromagnetic brake cooling structure for a phase varying device in an automobile engine.   The front edge of the outer peripheral wall of the clutch case is provided with an oil lead-out notch for leading out engine oil between the friction material and the relative sliding surface of the rotary drum to the outside. 2. The vehicle according to claim 1, wherein the engine oil is formed deeper than a bottom surface of the friction material holding plate, and engine oil in the clutch case is led out of the clutch case through the notch. Electromagnetic brake cooling structure of phase variable device in engine.   3. The electromagnetic wave of the phase varying device in an automobile engine according to claim 2, wherein the notch for introducing oil and the notch for extracting oil are provided so as to be offset in a circumferential direction of the clutch case. Brake cooling structure.   A part of the engine oil introduced into the relative sliding portion between the friction material and the rotary drum is led out by the oil introduction notch in the radially inner side of the disk surface of the rotary drum facing the friction material. An electromagnetic brake cooling structure for a phase varying device in an automobile engine according to any one of claims 1 to 3, wherein an oil outlet hole is provided.

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