JP7291583B2 - LASER WELDING METHOD AND JOINT STRUCTURE - Google Patents

Description

The present invention relates to a laser welding method and a joint structure.

Conventionally, there has been provided a laser welding method for welding a resin container and a resin lid covering an opening of the container by using a laser beam.

First, a cover member made of a laser-transmissive resin material is superimposed on the opening of a container made of a laser-absorbing resin material. By irradiating the joining surface of the container and the lid member with a laser beam while the overlapping portions are pressurized, they are melted and joined by welding.

When joining using such a laser welding method, there are cases where the resin material is not sufficiently melted and sufficient airtightness of the joint surface cannot be obtained.

Therefore, as described in Patent Literature 1 below, a technique has been provided in which airtightness can be ensured by sufficiently melting the entire joint surface according to the approach speed of both resin materials when they are melted. ing.

Japanese Patent Application Laid-Open No. 2009-119832 (Fig. 2)

However, in the laser welding method described in Patent Document 1, the melted resin material may flow out from between the container and the lid member, resulting in large burrs. The presence of this burr not only impairs the appearance quality of the container and the lid member, but may also cause problems in other devices due to the burr coming off.

The present invention provides a laser welding method and a joining structure capable of sufficiently joining the entire joining surface between a housing and a lid member, and preventing large burrs from being caused by a large amount of melted resin material flowing out to the outside. One purpose is to provide the body.

In the present invention, preferably, the laser beam is applied to a position within the thickness width of the joint portion from the cover member side and deviated to the inner peripheral side with respect to the center position of the thickness width of the joint portion. Characterized by

ADVANTAGE OF THE INVENTION According to one aspect of this invention, the whole joint surface can be fully joined, and it can suppress that the melted resin material flows out outside and protrudes greatly.

1 is a longitudinal sectional view showing a valve timing control device for an internal combustion engine according to a first embodiment of the invention; FIG. FIG. 2 is an exploded perspective view showing main constituent members in the embodiment; FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1; FIG. 4 is a perspective view showing a state before the lid member is joined to the cover member; FIG. 4 is a perspective view showing a state in which a lid member is joined to a cover member; FIG. 6 is a cross-sectional view taken along line BB of FIG. 5; FIG. 7 is an enlarged view of a C portion in FIG. 6; FIG. 5 is a cross-sectional view showing a state in which the color tone of the laser welded portion changes when the center position of the laser beam irradiation is shifted inward by a predetermined amount. It is a procedure flow of the laser welding method in this embodiment. FIG. 5 is a characteristic diagram showing the relationship between the amount of deviation of the center position of laser light irradiation and the bonding strength. FIG. 7 is an enlarged view of part C of FIG. 6 in the second embodiment;

An embodiment in which a laser welding method and a joint structure according to the present invention are applied to a valve timing control device for an internal combustion engine will be described below with reference to the drawings. The valve timing control system of this embodiment is applied to, for example, the intake side of a four-cylinder internal combustion engine.

1 is a longitudinal sectional view of a valve timing control device according to an embodiment of the present invention, FIG. 2 is an exploded perspective view showing main components of the valve timing control device, and FIG. 3 is a sectional view taken along the line AA of FIG. be.

As shown in FIGS. 1 and 2, a valve timing control device (hereinafter referred to as VTC) includes a timing sprocket 1 (hereinafter referred to as sprocket 1), which is a driving rotating body, and a bearing bracket 02 on a cylinder head 01. A camshaft 2 that is rotatably supported through a sprocket 1 and is rotated by a rotational force transmitted from a sprocket 1; a cover member 3 that is a housing fixed to a chain case 6 disposed in front of the sprocket 1; 1 and a camshaft 2, and a phase change mechanism 4 for changing the relative rotation phase of both 1 and 2 according to the engine operating state.

The sprocket 1 is rotationally driven through a timing chain by a crankshaft of an internal combustion engine.

The sprocket 1 is made of a ferrous metal and integrally formed into a ring. The inner peripheral surface of the sprocket 1 is a stepped diameter sprocket body 1a. A gear portion 1b that receives a rotational force from the crankshaft via an external timing chain, an internal tooth forming portion 5 that is integrally provided on the front end side of the sprocket body 1a and constitutes a part of the speed reduction mechanism 13 described later, consists of

The sprocket 1 is relatively rotatably supported by the driven member 9 by one large-diameter ball bearing 19 provided between the sprocket body 1a and the driven member 9, which will be described later.

The internal tooth forming portion 5 is integrally provided on the outer peripheral side of the front end portion of the sprocket main body 1a. The internal tooth forming portion 5 is formed in a cylindrical shape extending forward of the phase change mechanism 4, and has a plurality of corrugated internal teeth 5a formed on the inner periphery thereof.

A holding plate 8 is arranged and fixed to the rear end portion of the sprocket body 1a on the opposite side to the internal tooth forming portion 5 in the axial direction. The holding plate 8 is formed in an annular shape by a metal plate material such as an iron-based metal. As shown in FIG. 2, the holding plate 8 is integrally provided with a stopper convex portion 8b projecting radially inward, that is, toward the central axis, at a predetermined position on the inner peripheral edge of the inner peripheral portion 8a.

The stopper projection 8b is formed in a substantially trapezoidal shape, and the tip edge 8c is formed in an arc shape along the arc-shaped inner peripheral surface of the stopper groove 11b of the adapter 11, which will be described later. The tip edge 8c and the contact surface of the stopper groove 11b are in a non-contact state with a slight gap.

A plurality (eight in this embodiment) of bolt insertion holes 1c and 8d are formed through the outer peripheral portions of the sprocket body 1a (internal tooth forming portion 5) and the holding plate 8 at substantially equal intervals in the circumferential direction. ing.

A rear end portion of a motor housing 14 (to be described later) on the side of the camshaft 2 is arranged to face the front end side of the internal tooth forming portion 5 . A plurality of (six in this embodiment) female screw holes 14d are formed in the peripheral wall of the rear end portion of the motor housing 14 at positions corresponding to the respective bolt insertion holes 1c and 8d.

Therefore, the sprocket 1, the holding plate 8 and the motor housing 14 are fastened together from the rotation axis direction of the motor housing 14 by six bolts 7 inserted and screwed into the respective holes 1c, 8d and 14d.

The sprocket main body 1a and the internal tooth forming portion 5 are configured as a casing of a speed reduction mechanism 13, which will be described later.

The chain case 6 is arranged and fixed along the vertical direction in the direction of gravity so as to cover a chain (not shown) wound around the sprocket 1 on the front end side of the cylinder head 01 and the cylinder block of the internal combustion engine. The chain case 6 is integrally provided with a flange portion 6a on the outer peripheral edge of the front end portion. The chain case 6 has an annular groove 6b formed on the inner circumference of the front end. The annular groove 6b is formed such that the axial width extending from the front edge of the chain case 6 in the inner axial direction is larger than the thickness width of the flange portion 6a.

The camshaft 2 has two drive cams per cylinder for opening intake valves (not shown) on its outer periphery. The camshaft 2 is formed with a female thread 2b in the inner axial direction of one end 2a on the side of the sprocket 1 in the rotation axis direction. The camshaft 2 is connected to the driven member 9 by a cam bolt 10 via an adapter 11, which will be described later, in the rotation axis direction. A positioning pin (not shown) is axially press-fitted to the tip of one end 2a of the camshaft 2. As shown in FIG.

An oil passage hole 2d communicating with a discharge passage (main oil gallery) of an oil pump (not shown) is formed in one end portion 2a of the camshaft 2 in the axial direction thereof.

The driven member 9 is integrally formed of a metallic material such as a ferrous metal, and as shown in FIG. A cylindrical portion 9b projecting from the inner peripheral front end surface of the fixed end portion 9a in the axial direction of the rotation shaft of the driven member 9, and a shaft portion 10b of the cam bolt 10 is formed through the inside of the fixed end portion 9a and the cylindrical portion 9b. It has a bolt insertion hole 9c to be inserted.

The fixed end portion 9a has a fitting groove 9d formed around the bolt insertion hole 9c in the rear end surface on the side of the camshaft 2, into which the fixed portion 11a of the adapter 11 is fitted. A tip surface of one end portion 2a of the camshaft 2 is arranged to contact the bottom surface of the fitting groove 9d with an adapter 11 interposed therebetween.

A positioning groove (not shown) into which a positioning pin for the camshaft 2 is inserted together with the adapter 11 is formed in the rear end face of the fixed end portion 9a on the camshaft 2 side.

The cylindrical portion 9b is formed to extend in the direction of the electric motor 12, and a needle bearing 35 and a small-diameter ball bearing 36, which will be described later, are arranged in the axial direction on the outer peripheral surface of the cylindrical portion 9b.

The cam bolt 10 axially supports the inner ring of the small-diameter ball bearing 36 at the end face of the head portion 10a on the shaft portion 10b side. The cam bolt 10 has a male thread 10c that is screwed onto the female thread 2b of the camshaft 2 on the outer circumference of the tip of the shaft portion 10b.

As shown in FIGS. 1 and 2, the adapter 11 is integrally formed by press-molding a plate member made of iron-based metal, which is a metallic material, and has a substantially disk-like overall outer shape.

The adapter 11 has a bottomed cylindrical fixing portion 11a at the center, and a stopper recessed groove 11b into which the stopper projection 8b of the holding plate 8 is inserted is formed on the outer peripheral surface along the circumferential direction. ing.

The fixing portion 11a is press-formed to form a convex shape toward the driven member 9, and has a fitting concave portion 11c formed therein. In addition, the convex fixing portion 11 a has an annular peripheral wall 11 d whose outer peripheral surface is press-fitted into the inner peripheral surface of the fitting groove 9 d of the driven member 9 .

A bolt insertion hole 11e into which the shaft portion 10b of the cam bolt 10 is inserted is formed through the fixing portion 11a in the center of the bottom wall. A pin insertion hole into which a positioning pin (not shown) is inserted is formed through the side of the bolt insertion hole 11e of the bottom wall.

The stopper recessed groove 11b is formed on the outer peripheral surface of the adapter 11 at a position corresponding to the stopper protrusion 8b, and is formed in an arc shape having a predetermined length along the circumferential direction. One of the side edges of the stopper projection 8b abuts against one of the side edges of the stopper groove 11b facing each other in the circumferential direction. As a result, the relative rotational position of the camshaft 2 on the maximum advance side or the maximum retardation side with respect to the sprocket 1 is mechanically restricted.

As shown in FIGS. 1 to 3, the phase change mechanism 4 includes an electric motor 12 arranged on the front end side of the cylindrical portion 9b of the driven member 9, and a cam shaft 2 by reducing the rotational speed of the electric motor 12. and a deceleration mechanism 13 for transmission.

The electric motor 12 is a DC motor with brushes, and includes a motor housing 14 that rotates together with the sprocket 1 , a motor output shaft 15 that is rotatably provided inside the motor housing 14 , and It has four arc-shaped permanent magnets 16 fixed to the peripheral surface and a support plate 17 provided at the front end of the motor housing 14 .

The motor housing 14, as shown in FIGS. 1 and 2, has a housing body 14a, which is a yoke formed into a cylindrical shape with a bottom by press-molding a metallic material such as an iron-based metallic material. A disk-shaped partition wall 14b is provided on the rear end side of the housing body 14a. The partition wall 14b has a large-diameter shaft portion insertion hole 14c formed substantially in the center thereof, through which an eccentric shaft portion 25, which will be described later, is inserted. A cylindrical extending portion projecting in the rotation axis direction of the camshaft 2 is integrally provided at the hole edge of the shaft portion insertion hole 14c.

The motor output shaft 15 is formed in a stepped cylindrical shape and functions as an armature. and a small diameter portion 15b.

The large-diameter portion 15a has an iron core rotor 18 fixed to its outer periphery, and an eccentric shaft portion 25 that constitutes a part of the speed reduction mechanism 13 is integrally provided on the rear end side.

An annular member 20 made of a non-magnetic material is press-fitted and fixed to the outer circumference of the small diameter portion 15b. A commutator 21 is press-fitted and fixed to the outer peripheral surface of the annular member 20 from the axial direction.

A detected portion 22 of a rotation detecting mechanism for detecting the rotational position of the motor output shaft 15 is press-fitted and fixed to the inner peripheral surface of the small diameter portion 15b. The detected portion 22 is made of a synthetic resin material and has a lidded cylindrical shape. In addition, an oil seal 22b is provided on the outer periphery of the detected portion 22 to seal between the inner peripheral surface of the motor output shaft 15 and the detected portion 22 .

The core rotor 18 is made of a magnetic material having a plurality of magnetic poles, and is configured as a bobbin having a slot around which the coil wire of the coil 18a is wound.

The commutator 21 is formed in an annular shape from a conductive material, and is fixed to the outer circumference of the annular member 20 made of the non-magnetic material by, for example, press fitting. The commutator 21 is electrically connected to each segment divided into the same number of poles as the iron core rotor 18, and the terminal 18b of the coil wire drawn out from the coil 18a.

Each permanent magnet 16 is arranged in a cylindrical shape along the circumferential direction with minute gaps interposed therebetween. Each permanent magnet 16 has a plurality of magnetic poles in the circumferential direction, and the position of the housing body 14a in the rotation axis direction is offset from the fixed position of the iron core rotor 18 toward the cover member 3 .

The support plate 17 is formed in a disc shape as a whole, and has a shaft insertion hole 17a at a central position through which one end of the motor output shaft 15 is inserted. The support plate 17 has a resin portion 27 which is a disk-shaped insulating member (non-magnetic material) and a metal core 28 which is a disk-shaped reinforcing member embedded in the resin portion 27. ing.

The support plate 17 includes a plurality (four in this embodiment) of holders 23a to 23d fixed to the resin portion 27, and is housed and arranged inside each of the holders 23a to 23d so as to be slidable along the radial direction. , four commutation brushes 24a to 24d, which are switching brushes whose tip surfaces are in elastic contact with the outer peripheral surface of the commutator 21 from the radial direction by the spring force of coil springs (not shown), Inner and outer double annular power supply slip rings 26a and 26b embedded and fixed in an exposed state, and a pigtail harness (not shown) that electrically connects each brush 24a to 24d and each slip ring 26a and 26b , is equipped with

Each of the holders 23a to 23d is fixed to the resin portion 27 by thermally crushing each of the four projecting portions 27a and 27b projecting from the resin portion 27, respectively.

The cored bar 28 is formed in a disc shape from, for example, an iron-based metal having higher rigidity than the resin portion 27 . Further, the core metal 28 is formed with deformed groove holes (not shown) through the inner peripheral portion thereof for arranging and holding the four holders 23a to 23d inside, respectively. The support plate 17 as a whole is positioned and fixed by caulking the outer peripheral portion 28a of the core metal 28 exposed from the outer periphery of the resin portion 27 to a recessed stepped portion formed on the inner periphery of the front end portion of the motor housing 14 .

Each of the slip rings 26a and 26b has a plurality of protrusions (not shown) integrally formed on the inner and outer peripheral edges thereof. The protrusions are molded with resin to integrally fix the slip rings 26a and 26b to the resin portion 27. As shown in FIG.

4 is a perspective view showing a state before the cover member is joined to the cover member, FIG. 5 is a perspective view showing the state where the cover member is joined to the cover member, and FIG. 6 is a cross-sectional view taken along line BB in FIG. , and FIG. 7 is an enlarged view of the portion C in FIG.

As shown in FIGS. 1 and 2, the cover member 3 is disposed so as to cover the front end of the motor housing 14 and is entirely made of a synthetic resin material so that the overall shape is substantially disk-shaped. there is As the synthetic resin material, polyphenylene sulfide resin (PPS resin), which has an absorptive property for laser light of a predetermined wavelength, is used. This PPS resin is a crystalline resin and has low permeability, but is excellent in heat resistance and high temperature characteristics. It is also possible to embed a metal plate as a reinforcing material inside the synthetic resin material.

As also shown in FIGS. 4 to 6, the cover member 3 has a disk-shaped cover body 3a and an annular mounting flange 3b integrally formed on the outer peripheral edge of the cover body 3a on the opening side. are doing.

The cover main body 3a has an insertion hole 3c through which the tip of the detected portion 22 is inserted. Further, the cover main body 3a is integrally provided with an annular wall 3d, which is a joining portion that rises annularly, on the outer peripheral side of the rear surface side. As shown in FIG. 7, the annular wall 3d has a thickness width W of about 3 mm. Further, a flat joint surface 3e to be jointed with a lid member 30, which will be described later, is formed on the front end surface (upper end surface in the drawing) of the annular wall 3d. The cover member 3 has a storage chamber, which is an opening, formed inside the annular wall 3d.

As shown in FIG. 4, the cover main body 3a has a plurality of reinforcing ribs 3f arranged in a grid pattern in a storage chamber partitioned by an annular wall 3d. A detection circuit 52, an integrated circuit 53, a capacitor, and the like, which are electronic components having a receiving circuit and an excitation circuit of the rotation detection mechanism, are held in the central storage compartment partitioned by the reinforcing ribs 3f.

A lid member 30 for covering and protecting the detection circuit 52, the integrated circuit 53, and the like is joined and fixed to the joining surface 3e of the annular wall 3d by laser welding.

As shown in FIGS. 4 to 6, the lid member 30 is made of a synthetic resin material and formed into a thin, substantially rectangular plate. The lid member 30 is made of PPS resin as the synthetic resin material used for the cover member 3, and is molded of a resin material that is transparent to laser light of the same predetermined wavelength.

The cover member 30 is provided with a pressure adjusting portion 30a for adjusting the pressure inside the cover main body 3a at the central portion. As shown in FIGS. 6 and 7, the lid member 30 is integrally provided with an annular convex portion 30b for positioning on the outer peripheral side of the inner surface of the cover member 3 side. An annular rib 30c is integrally provided on the outer peripheral side of the outer surface of the lid member 30 inside the annular convex portion 30b. The lid member 30 is integrally provided with two convex portions 30g and 30h that cover two brush holders 29 and 29, which will be described later.

Further, the lid member 30 is integrally provided with a contact portion 30d that contacts the joint surface 3e of the cover main body 3a on the outer peripheral portion outside the annular convex portion 30b. As shown in FIG. 7, the contact portion 30d is formed in an annular shape with a thickness width W1 of about 1 mm. have. This contact surface 30e is formed in a flat annular shape following the joint surface 3e.

An annular collar portion 30f having a larger diameter than the outer peripheral surface of the annular wall 3d (the outer peripheral edge of the joint surface 3e) is provided integrally with the outer peripheral edge of the contact portion 30d. The flange portion 30f has a shape extending outward from the contact portion 30d. A protrusion amount Z is set to about 0.5 mm. The thickness width W1 of the flange portion 30f is about 1 mm, the same as that of the contact portion 30d.

In this embodiment, the cover member 3 and the lid member 30 are made of PPS resin. (PEEK), polycarbonate (PC), polyamide (PA), polyethylene (PE), etc. can also be used.

It should be noted that the laser light transmittance of the cover member 30 can be limited to only the region of the contact portion 30d.

A specific method of joining the joint surface 3e and the contact surface 30e with a laser beam will be described later.

As shown in FIGS. 1, 2, 4, and 5, the cover member 3 includes a power supply connector 31 protruding downward from the cover body 3a, and a signal connector 31 arranged on the side of the power supply connector 31. and a connector 32 are integrally provided.

The power supply connector 31 has a pair of elongated conductive terminal strips (not shown) partially disposed inside the cover body 3a. Each terminal piece is bent into a crank shape inside the cover main body 3a, and one end portion inside is connected to two power supply brushes 33, 33 via a pigtail harness (not shown). On the other hand, the other end of each terminal piece is exposed from the cover main body 3a through a connector portion and connected to a control unit (ECU) for controlling an engine (not shown). A pair of electromagnetic noise suppressing mechanisms (not shown) are provided in the middle of each of the pair of terminal strips. The pair of electromagnetic noise suppressing mechanisms includes an inductance coil connected in series in the middle of the pair of terminal strips, one terminal of which is connected to the terminal strip, and the other terminal of which is electrically connected to the ground of the engine. and a

As shown in FIG. 1, the signal connector 32 has a pair of elongated conductive terminal strips 32a partly disposed inside the cover body 3a. One end of each terminal strip 32a is electrically connected to the integrated circuit 53 via a harness, and the other end 32c is exposed in the connector and connected to the ECU.

The integrated circuit 53 receives an information signal from the detection circuit 52 that receives the signal output from the detected portion 22 .

The mounting flange 3b is formed in an annular shape, and is integrally provided with a plurality of (four in this embodiment) boss portions 3g at substantially equal intervals on the outer peripheral surface. A bolt insertion hole 3h made of a metal sleeve is formed through each boss portion 3g. The mounting flange 3b is fastened and fixed to the flange portion 6a of the chain case 6 by mounting bolts (not shown) inserted into the respective bolt insertion holes 3h.

A seal ring 50 made of rubber is arranged between the inner end surface of the mounting flange 3b on the side of the motor housing 14 and the front end surface of the flange portion 6a of the chain case 6 facing the inner end surface. It is

A large-diameter oil seal 51 is interposed between the inner peripheral surface of the annular groove 6 b of the chain case 6 and the outer peripheral surface of the motor housing 14 .

As shown in FIGS. 1 and 2, the cover body 3a has two brush holders 29, 29 fixed at positions corresponding to the respective slip rings 26a, 26b.

Each brush holder 29 is formed of a conductive material in a square tube shape, and slidably accommodates power supply brushes 33, 33 therein. Each brush holder 29, 29 is integrally fixed to the cover member 3 when the cover member 3 is molded with resin.

A pair of power supply brushes 33, 33 are axially slidably held in the receiving holes of the brush holders 29, the tip surfaces of which contact the respective slip rings 26a, 26b in the axial direction. Each power supply brush 33 is formed in a prism shape corresponding to the shape of each brush holder 29 and has a rectangular cross section, and is set to have a predetermined length in the axial direction.

Each power supply brush 33 is urged toward each slip ring 26a, 26b by the spring force of a pair of torsion coil springs 34, 34 provided on the back side of the cover body 3a.

One end of a pigtail harness (not shown) is inserted into a small hole 33a formed in one side surface of the rear end of each power supply brush 33, and fixed by soldering, for example.

The motor output shaft 15 and the eccentric shaft portion 25 are composed of a small-diameter ball bearing 36 provided on the outer peripheral surface of the shaft portion 10b on the head portion 10a side of the cam bolt 10, and a needle provided on the outer peripheral surface of the cylindrical portion 9b of the driven member 9. It is rotatably supported by bearings 35 .

Lubricating oil is prevented from leaking into the electric motor 12 from the inside of the speed reduction mechanism 13 between the outer peripheral surface of the motor output shaft 15 (eccentric shaft portion 25) and the inner peripheral surface of the extending portion of the motor housing 14. A small diameter oil seal 40 is provided to block.

The ECU described above detects the current engine operating state based on information signals from various sensors (not shown) such as a crank angle sensor, air flow meter, water temperature sensor, and accelerator opening sensor, and controls the engine. Further, the ECU controls the rotation of the motor output shaft 15 by energizing the coil 18a, and controls the relative rotation phase of the camshaft 2 with respect to the sprocket 1 via the speed reduction mechanism 13. FIG.

As shown in FIGS. 1 to 3, the reduction mechanism 13 includes an eccentric shaft portion 25 that performs eccentric rotational motion, a medium-diameter ball bearing 37 provided on the outer circumference of the eccentric shaft portion 25, and an outer circumference of the medium-diameter ball bearing 37. and a cylindrical cage that is a holding member that is integrally provided on the outer peripheral portion of the fixed end portion 9a and that holds the plurality of rollers 38 in the rolling direction while allowing radial movement. 39 and a driven member 9 integral with the retainer 39 .

The eccentric shaft portion 25 has a cam surface 25a formed on the outer peripheral surface thereof whose axis Y is slightly eccentric from the axis X of the motor output shaft 15 in the radial direction.

The medium-diameter ball bearing 37 is disposed in a state in which the entirety thereof substantially overlaps at a radial position of the needle bearing 35. Balls 37c are provided between the inner ring 37a and the outer ring 37b and between the two rings 37a and 37b via retainers. consists of

The inner ring 37a is press-fitted and fixed to the outer peripheral surface of the eccentric shaft portion 25, while the outer ring 37b is in a free state without being fixed in the axial direction. That is, the outer ring 37b has one end face in the direction of the rotation axis that does not contact any part, and the other end face in the axial direction of the outer ring 37b has a small first gap between it and the inner side surface of the base of the retainer 39 that faces it. is formed and is in a free state.

The outer peripheral surface of each roller 38 is in rolling contact with the outer peripheral surface of the outer ring 37b. An annular second gap is formed on the outer peripheral side of the outer ring 37b. This second gap allows the entire medium-diameter ball bearing 37 to move radially with the eccentric rotation of the eccentric shaft portion 25, that is, to move eccentrically.

Each roller 38 is made of, for example, a ferrous metal, and moves radially with the eccentric movement of the medium-diameter ball bearing 37 . Further, the total number of each roller 38 is one less than the total number of teeth of the internal teeth 5 a of the internal tooth forming portion 5 .

Each of the rollers 38 is guided in the circumferential direction by holding pieces 39c and 39d provided on both sides of a roller holding hole 39b of the retainer 39, which will be described later, and oscillates in the radial direction.

As shown in FIGS. 1 and 2, the retainer 39 is bent forward from the front end of the outer peripheral portion of the fixed end portion 9a to have a substantially L-shaped cross section, and is integrally connected to the fixed end portion 9a. It has a cylindrical portion 39a that is integrally formed on the outer circumference of the base and protrudes in the same direction as the cylindrical portion 9b.

The cylindrical portion 39a extends toward the partition wall 14b of the motor housing 14 through an annular recessed accommodation space formed between the female screw hole 14d and the extending portion. In addition, a plurality of substantially rectangular roller holding holes 39b (for example, 50 in this embodiment) for holding a plurality of rollers 38 in a freely rolling manner are provided at substantially equal intervals in the circumferential direction of the tubular portion 39a. are formed at equally spaced positions in the direction.

Each of the roller holding holes 39b is formed as an elongated rectangular long hole along the rotation axis direction of the cylindrical portion 39a at predetermined intervals in the circumferential direction of the cylindrical portion 39a.

Lubricating oil is supplied to the interior of the reduction mechanism 13 by a lubricating oil supply means. As shown in FIG. 1, this lubricating oil supply means is formed in an oil passage hole 2d formed in the internal axial direction of the camshaft 2 from the inside of the cylinder head 01 and in the fixed portion 11a of the adapter 11, and the oil passage An oil supply hole 43 communicating with the hole 2d is formed through the interior of the driven member 9 in the axial direction. and an oil discharge hole (not shown) also formed through the driven member 9 .
[Method of Laser Welding Cover Member and Lid Member]
Hereinafter, a laser welding method for joining the joint surface 3e of the cover member 3 and the contact surface 30e of the lid member 30 will be described.

The laser welding machine is a general one, and one with a laser beam output of 60 W to 100 W, for example, is used.

FIG. 9 shows a procedure flow of laser welding. As described in step S1, a plurality of electronic components such as a detection circuit 52, an integrated circuit 53, and a capacitor are mounted and arranged at predetermined positions within the cover body 3a of the cover member 3. do.

In step S2, the cover member 3 with the electronic components mounted thereon is installed and fixed at a predetermined position of the laser welding equipment.

In step S3, the cover member 30 is placed on the joint surface 3e of the annular wall 3d of the cover member 3 while being radially positioned via the annular convex portion 30b. In this state, the abutment portion 30d (abutment surface 30e) of the cover member 30 is pressed by a pressing jig (not shown) toward the annular wall 3d (joint surface 3e) of the cover member 3 with a load within a range of, for example, 500 to 700N. press. It should be noted that the pressing jig is made of a material that is transparent to the laser beam at the location where it is pressed. Moreover, the load mainly acts on the joint surface 3e.

After that, in step S4, the lid member 30 is irradiated with a laser beam R from above by a laser welding machine (not shown) while being held down by a holding jig.

As shown in FIG. 7, the laser beam R of the laser welding machine has a conical shape with a tapered tip, and the center position S of the irradiation is an annular projection from the center position S1 of the thickness width W of the joint surface 3e. It is positioned closer to the portion 30b, that is, deviated to the inner side of the annular wall 3d within a range of less than 0.8 mm. In this embodiment, it is offset inwardly of the annular wall 3d by 0.6 mm, for example.

The irradiation of the laser beam R is performed, for example, by a circular method in which the laser beam R condensed in a spot shape is transmitted through the contact portion 30d and sequentially scanned along the circumferential direction of the bonding surface 3e over the entire circumference of the bonding surface 3e. do. As a result, the entire periphery of the joint surface 3e is irradiated. In this embodiment, the irradiation of the laser light R is performed under the same output condition of, for example, 60 W in the circumferential direction of the joint surface 3e, and is performed at the same speed in the circumferential direction.

When the laser beam R is irradiated, the joint surface 3e and the annular wall 3d in the vicinity thereof are melted by absorption of the laser beam to form a molten resin portion 41. As shown in FIG. The molten resin portion 41 is formed along the entire circumference of the joint surface 3e between the annular wall 3d and the contact portion 30d. Then, as shown in FIG. 7, part of it flows out into the cover main body 3a from the inside of the joint surface 3e, that is, between the both 3e and 30d, and protrudes to form a burr 41a (first resin outflow portion). As a result, the molten resin portion 41 adheres to and adheres to the inner peripheral surface of the annular wall 3d and the lower surface of the lid member 30 in the drawing.

After the laser beam irradiation work is completed, in step S5, an airtightness test is performed between the joint surface 3e and the contact surface 30e. A pressure of, for example, 49 kPa is applied to the inside of the cover member 3 at room temperature, and it is checked whether the amount of air released is equal to or smaller than 1 cc/min.

As described above, the deviation amount α of the irradiation center position S of the laser beam is set within a range of less than 0.8 mm from the center position S1 of the thickness width W of the joint surface 3e to the inner side of the annular wall 3d. This is obtained from the results of an experiment conducted by the inventor of the present application shown in FIG.

That is, in FIG. 10, the vertical axis represents the bonding strength (a.u.) between the bonding surface 3e and the contact surface 30e, and the horizontal axis represents the amount of inner deflection (mm) of the laser beam irradiation position. An experiment was carried out on the relationship between the amount and the bonding strength.

According to this experimental result, when the irradiation center position S of the laser beam is the same as the center position S1 of the thickness width W of the joint surface 3e (0 mm), the joint strength is 1a. u. becomes. When the irradiation center position S was deviated inward from the center position S1 of the thickness width W by 0.2 mm, the bonding strength increased slightly from 1.0. Furthermore, when the inward bias is 0.4 mm and 0.6 mm, the bond strength is further stepped up to about 1.15a. u. ~1.18a. u. was found to rise to

Further, when the deviation amount α of the irradiation center position S is increased to 0.8 mm, the bonding strength becomes slightly smaller than the case of 0.6 mm, but is almost the same as the case of 0.4 mm, 1.18a. u. become.

Further, when the deviation amount α of the irradiation center position S is increased to 1 mm, the bonding strength becomes even smaller than when the deviation amount α is 0 mm, and 1a. u. It turned out to be:

From the results of this experiment, it is preferable to set the deflection amount α of the irradiation center position S in the range of 0 to 0.8 mm because sufficient bonding strength can be obtained. Therefore, the deviation amount α is set to 0.8 mm or less. However, considering the magnitude of the bonding strength, it is more preferable that the deviation amount α is 0.6 mm or less.

As for the airtightness, as a result of the experiment as described above, sufficient airtightness was obtained when the deviation amount α was within the range of 0 to 0.8 mm in proportion to the bonding strength.

FIG. 8 is a cross-sectional view showing a state in which the color tone of the laser-welded portion changes when the irradiation center position S of the laser beam is shifted inward by 0 to 0.8 mm.

That is, as described above, when the deviation amount α of the irradiation center position S of the laser beam is set, for example, within the range of 0.2 to 0.8 mm, the resin material is melted and recrystallized by the laser beam irradiation. In some cases, as shown in FIG. 8, the arc-shaped recrystallized portion 42 (shaded portion) can be visualized by changing the color tone.

This change in color tone is only on the side of the lid member 30 on the side of the laser light transmissive resin, and cannot be confirmed on the cover member 3 because it is black.

When the resin material is melted and recrystallized by laser light irradiation, the color tone change phenomenon can be visualized as a change in color tone because the degree of crystallinity differs from that before laser light irradiation. Before the laser irradiation, the recrystallized portion 42 basically becomes a color close to translucent yellow in contrast to white (natural color).

Therefore, it is considered that the recrystallized portion 42 has a lower degree of crystallinity (a change in transparency).
[Activation of VTC]
The operation of the VTC according to this embodiment will be briefly described below.

First, the sprocket 1 rotates as the crankshaft of the engine is driven to rotate, and the rotational force of the sprocket 1 rotates the motor housing 14 , that is, the electric motor 12 synchronously via the internal tooth forming portion 5 . On the other hand, the rotational force of the internal tooth forming portion 5 is transmitted from each roller 38 to the camshaft 2 via the retainer 39 and the driven member 9 . As a result, the cams of the camshaft 2 open and close the intake valves.

During a predetermined engine operation after the engine is started, the ECU supplies power to the coil 18a of the electric motor 12 through the power supply brushes 33, 33, the slip rings 26a, 26b, the rectifying brushes 24a to 24d, and the commutator 21. be. As a result, the motor output shaft 15 is rotationally driven, and the reduced rotational force is transmitted to the camshaft 2 via the speed reduction mechanism 13 .

That is, when the eccentric shaft portion 25 rotates eccentrically with the rotation of the motor output shaft 15, the rollers 38 are guided in the radial direction by the roller holding holes 39b of the retainer 39 each time the motor output shaft 15 rotates. It moves over one internal tooth 5a of the component 5 and rolls to another adjacent internal tooth 5a. Each roller 38 rolls in the circumferential direction while repeating this in sequence. Rotational force is transmitted to the driven member 9 while the rotation of the motor output shaft 15 is decelerated by the rolling contact of the rollers 38 . The speed reduction ratio at this time can be arbitrarily set by the number of rollers 38 or the like.

As a result, the camshaft 2 rotates forward and backward relative to the sprocket 1 to change the relative rotation phase, thereby controlling the opening/closing timing of the intake valve to advance or retard.

Further, in this embodiment, the joint surface 3e of the cover member 3 and the contact portion 30d of the lid member 30 can be firmly joined by laser welding, and deterioration of appearance quality can be suppressed.

That is, in the prior art described in the above-mentioned publication, it is possible to adjust the irradiation power of the laser light in order to prevent the burr from protruding outside, but the irradiation power of the laser light is reduced. As a result, there is a risk that a gap that affects airtightness will be generated in the joint.

When this laser welding is applied to, for example, a part of an internal combustion engine, there is a risk of a technical problem that the bonding state deteriorates if vibration is applied for a long time in the bonded state as described above.

In the case of partially melting and joining, the joint strength is increased by flowing the molten resin material to the outer peripheral side edge or the inner peripheral side edge of the joint, and vibration is applied for a long time. It is possible to maintain the strength even However, if a large amount of molten resin material flows out to the outer peripheral side edge of the joint, the same technical problem as in the prior art occurs, namely that the quality of the appearance is impaired.

Therefore, in the present embodiment, in particular, the irradiation center position S of the laser beam is set to a position shifted inward from the center position S1 in the thickness width direction of the joint surface 3e. Therefore, the molten resin portion 41 melted by the irradiation of the laser beam only partly flows out to the inside of the annular wall 3d (the burr 41a first resin flow-out portion), so that the flow-out to the outside can be suppressed. . Therefore, deterioration of the appearance quality of the cover member 3 and the lid member 30 can be suppressed, and the joint strength between the two members 3 and 30 is improved by the burr 41a formed by the outflow to the inside.

In addition, since the laser beam is irradiated over the entire circumference between the joint surface 3e and the contact surface 30e, the cover member 3 and the lid member 30 can be strongly welded together over the entire circumference.

As described above, in the present embodiment, a portion of the molten resin portion 41 is prevented from protruding significantly outside the cover member 3 and the lid member 30, so deterioration in appearance quality can be prevented. Moreover, since the joint strength between the joint surface 3e including the burr 41a and the contact surface 30e is equal to or greater than that, sufficient durability against vibrations of the internal combustion engine can be obtained.

Furthermore, since the cover member 3 and the lid member 30 are made of PPS resin material, sufficient heat resistance can be ensured, and the present embodiment can be applied to a valve timing control device for an internal combustion engine that generates high heat. .

Furthermore, since the PPS resin material has a low material cost, it is possible to reduce the manufacturing cost.
[Second embodiment]
FIG. 11 shows the second embodiment, and the basic configuration is the same as in the first embodiment, such as deviating the irradiation center position S of the laser beam inward from the center position S1 of the thickness width W of the joint surface 3e by a predetermined amount. be.

The difference is that the molten resin portion 41 melted by the laser beam flows out to the inside of the annular wall 3d to form an inner burr 41a (first resin outflow portion), and in addition, there is a slight amount of burr on the outside of the annular wall 3d. outside burr 41b (second resin outflow portion) is formed.

The amount of protrusion, that is, the amount of protrusion of the outer burr 41b is inside the flange 30f of the lid member 30, and is covered with the flange 30f. In addition, the outer burr 41b is also formed along the entire circumference between the joint surface 3e and the contact surface 30e of the contact portion 30d as the laser beam is irradiated over the entire circumference between the joint surface 3e and the contact surface 30e of the contact portion 30d. formed over the

Therefore, according to the second embodiment, the inner burrs 41a and the outer burrs 41b form the joint surface 3e and its surroundings and the contact surface 30e and its surroundings. is joined more firmly.

Moreover, the presence of the outer burrs 41b makes it possible to visually confirm from the outside that the joint surface 3e and the contact surface 30e are entirely joined together. In other words, it is possible to visually recognize that the bonding surface 3e and the contact surface 30e are bonded over the entire circumference.

Further, since the outer burr 41b does not protrude from the outer peripheral edge of the flange portion 30f and is positioned inside the flange portion 30f, deterioration of appearance quality can be suppressed.

Since other configurations are the same as those of the first embodiment, the same effects as those of the above-described first embodiment can be obtained.

The present invention is not limited to the configurations of the above-described embodiments, and for example, a timing pulley other than a timing sprocket may be used as the drive rotor.

Also, the laser welding method and the joint structure of the present invention can be applied to devices and equipment other than the valve timing control device of the internal combustion engine as in the present embodiment. In this case, it is possible to use a resin material other than the PPS resin for the housing and the cover member for devices that do not require heat resistance.

As the laser welding method and the joint structure based on the embodiments described above, for example, the following modes are conceivable.

In one embodiment, a cover member made of a resin material that is transparent to laser light is joined by laser welding to an opening of a housing that is made of a resin material that is absorptive to laser light. A laser welding method for
The opening of the housing is integrally formed with a joint portion having a thickness width that surrounds the opening, while the outer circumference of the lid member is integrally formed with a contact portion that abuts against the joint portion. and a load is applied while the joint portion and the contact portion are in contact with each other. a laser beam is irradiated to a position deviated toward the inner peripheral side of the opening with respect to the central position of the joint in the thickness width direction, and the space between the joint and the contact portion is melted by the irradiation of the laser beam. The joint portion and the contact portion are rotated so that the melted resin material flows out to at least the inner peripheral side edge portion of the joint portion on the side of the opening portion.

According to this aspect of the invention, the joint portion of the housing and the abutting portion of the lid member can be firmly joined, and the melted resin material is prevented from flowing out and protruding outside the joint portion of the housing. becomes possible.

More preferably, the lid member integrally has a flange protruding outward from the joint portion on the outer periphery of the contact portion,
The joint portion and the contact portion are melted, and the laser beam is circulated so that the melted resin material flows on at least a part of the housing-side surface of the flange portion.

More preferably, the laser light is circulated between the joint portion and the contact portion under at least the same output conditions.

According to this aspect of the invention, it is possible to reliably join the joint portion and the contact portion over the entire circumference.

More preferably, the laser light circulates at the same speed between the joint portion and the contact portion.

According to this aspect of the invention, it is possible to reliably join the joint portion and the contact portion over the entire circumference.

More preferably, the laser beam is directed to a position within the range of the thickness width of the joint and deviated from the central position in the thickness width direction of the joint to the inner peripheral side of the opening by 0.8 mm or less. It is designed to be irradiated.

In an experiment conducted by the inventor of the present invention, it was found that by irradiating a position deviated within the specified numerical range, a strong joint can be formed between the joint portion and the contact portion, and the melted resin housing Outflow to the outside from the opening of the can be suppressed.

In another preferred embodiment, the bonded structure is a member that is molded from a resin material that absorbs laser light and has an opening, wherein the opening has a thickness width that circulates around it. a housing integrally having a joint portion;
It is molded from a resin material that is transparent to laser light, integrally has a contact portion that contacts the joint portion, and is fixed to the housing by joining the joint portion to the contact portion. a lid member;
A laser beam is emitted to a position within the thickness width range of the joint portion at the contact portion between the joint portion and the contact portion and deviated toward the inner peripheral side with respect to the central position in the thickness width direction of the joint portion. A laser irradiation site formed by irradiation of
A first resin outflow portion that flows out from the laser irradiation portion is provided in at least a part of inner circumferences of the joint portion and the contact portion.

According to this aspect of the invention, the joint surface of the joint portion of the housing and the contact portion of the lid member can be firmly joined, and the molten resin material flows out and protrudes outside the joint portion of the housing. can be suppressed.

More preferably, the lid member includes at least a flange protruding outside the joint on the outer periphery of the contact portion, and a surface of the flange on the housing side from the joint and the contact portion. A second resin outflow part that flows out from the laser irradiation part is provided in a part,
The second resin outflow portion has a maximum outflow width to the outer peripheral side from the joint portion that is smaller than the maximum outflow width to the inner peripheral side from the joint portion in the first resin outflow portion, positioned.

According to this aspect of the invention, it is possible to confirm that the entire surface of the joint is joined, and the second resin outflow portion is located inside the flange without protruding from the outer peripheral edge of the flange. Therefore, it is possible to suppress deterioration of subsequent assembly workability and appearance quality.

More preferably, the first resin outflow portion is provided along the entire circumference of the inner circumference side of the joint portion.

As a result, the entire inner periphery of the joint portion and the contact portion is reliably joined.

More preferably, the second resin outflow portion is provided along the entire periphery of the flange portion on the housing side.

According to this aspect of the invention, the second resin outflow portion can be visually observed from the outside, so that it can be recognized that the joint portion and the contact portion are joined over the entire circumference.

More preferably, electronic components are arranged in the housing.

More preferably, the housing and lid member are attached to a valve timing control device provided on a camshaft of an internal combustion engine.

According to this, it is possible to secure a joint strength that can withstand the vibration of the internal combustion engine.

More preferably, the resin material of each of the housing and lid member is polyphenylene sulfide resin (PPS resin).

By using the PPS resin material for the housing and the cover member, heat resistance can be ensured, so that it can be applied to, for example, a valve timing control device for an internal combustion engine, which is subject to high heat, and is advantageous in terms of cost.

DESCRIPTION OF SYMBOLS 1... Timing sprocket (drive rotary body) 1a... Sprocket main body 2... Camshaft 3... Cover member (housing) 3a... Cover main body 3d... Annular wall (joint part) 3e... Joint surface 4... Phase change mechanism 5... Internal tooth forming part 5a... Internal tooth (meshing part) 9... Driven member (driven rotating body) 12... Electric motor 13... Reduction mechanism 14... Motor housing 14a... Housing body, 15 Motor output shaft 17 Support plate 21 Commutator 23a to 23d Holder 24a to 24d Commutation brush 26a Inner slip ring 26b Outer slip ring 30 Lid member 30d Contact Contact portion 30e Contact surface 30f Collar 41 Molten resin portion 41a Inner burr 41b Outer burr R Laser beam S Center position of laser beam irradiation S1 Annular wall thickness Center position of thickness, Z...Protrusion amount of flange

Claims (11)

It is a laser welding method in which a cover member made of a laser-transmissive resin material is joined to an opening of a housing made of a laser-absorbing resin material by laser welding. hand,
The opening of the housing is integrally formed with a joint having a thickness and width that goes around the opening,
On the other hand, a contact portion that contacts the joint portion is integrally formed on the outer periphery of the lid member,
applying a load while the joint portion and the contact portion are in contact with each other;
In the state where this load is applied, from the side of the lid member, it is within the range of the thickness width of the joint portion and is biased toward the inner peripheral side of the opening with respect to the central position in the thickness width direction of the joint portion. irradiate the position with a laser beam,
The joint portion is melted by the irradiation of the laser beam, and the melted resin material flows out to at least the inner peripheral side edge portion of the joint portion on the side of the opening portion. and rotate the contact portion,
The laser beam is irradiated from a flat upper surface of the contact portion in a thickness direction in a direction perpendicular to the upper surface, and is within the thickness width of the joint portion. A laser welding method, wherein the laser beam is irradiated to a position deviated by 0.8 mm or less toward the inner peripheral side of the opening from the center position of the direction . The lid member integrally has a flange projecting outward from the joint portion on the outer periphery of the contact portion,
2. The laser beam is circulated so that the joint portion and the contact portion are melted and the melted resin material flows on at least a part of the housing-side surface of the flange portion. The laser welding method described in . 2. The laser welding method according to claim 1, wherein the laser beam is circulated between the joining portion and the contact portion under at least the same output conditions. 2. The laser welding method according to claim 1, wherein the laser beam circulates at the same speed between the joining portion and the contact portion. A housing that is molded from a resin material that absorbs laser light and has an opening, wherein the opening is integrally provided with a joint portion having a thickness and width that circulates around the opening;
It is molded from a resin material that is transparent to laser light, integrally has a contact portion that contacts the joint portion, and is fixed to the housing by joining the joint portion to the contact portion. a lid member;
A laser beam is emitted to a position within the thickness width range of the joint portion at the contact portion between the joint portion and the contact portion and deviated toward the inner peripheral side with respect to the central position in the thickness width direction of the joint portion. A laser irradiation site formed by irradiation of
a first resin outflow portion that flows out from the laser irradiation portion at least part of the inner periphery of the joint portion and the contact portion;
with
The laser irradiation portion is irradiated with the laser beam from a flat upper surface of the contact portion in a thickness direction from a direction perpendicular to the upper surface, and is within the thickness width of the joint portion, A bonded structure characterized by being formed by irradiating a position deviated by 0.8 mm or less toward the inner peripheral side of the opening from the central position in the thickness width direction of the bonded portion. A housing that is molded from a resin material that absorbs laser light and has an opening, wherein the opening is integrally provided with a joint portion having a thickness and width that circulates around the opening;
It is molded from a resin material that is transparent to laser light, integrally has a contact portion that contacts the joint portion, and is fixed to the housing by joining the joint portion to the contact portion. a lid member;
A laser beam is emitted to a position within the thickness width range of the joint portion at the contact portion between the joint portion and the contact portion and deviated toward the inner peripheral side with respect to the central position in the thickness width direction of the joint portion. A laser irradiation site formed by irradiation of
a first resin outflow portion that flows out from the laser irradiation portion at least part of the inner periphery of the joint portion and the contact portion;
with
The lid member includes a flange protruding outward from the joint on the outer periphery of the contact portion, and at least a part of the housing-side surface of the flange from the joint and the contact portion, a second resin outflow portion flowing out from the laser irradiation portion;
with
The second resin outflow portion has a maximum outflow width to the outer peripheral side from the joint portion that is smaller than the maximum outflow width to the inner peripheral side from the joint portion in the first resin outflow portion, A junction structure, characterized in that : 7. The joint structure according to claim 6 , wherein the first resin outflow portion is provided along the entire circumference of the inner circumference of the joint portion . 8. The joint structure according to claim 7 , wherein the second resin outflow portion is provided along the entire periphery of the flange portion on the housing side . 7. The joint structure according to claim 6 , wherein an electronic component is arranged in said housing . 10. The joint structure according to claim 9, wherein the housing and lid member are attached to a valve timing control device provided on a camshaft of an internal combustion engine. 7. The joint structure according to claim 6 , wherein the resin material of each of the housing and the lid member is polyphenylene sulfide resin (PPS resin) .

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