Method and apparatus for inserting a valve into a valve guide

Upper and lower support members, supporting a valve, are lowered toward a valve guide with at least the lower support member vibrated by a vibrating device. When a lower-end chamfered surface of the valve has failed to be brought into contact with the opening edge of the guide through the lowering, not only the upper support member is caused to gradually move away from an umbrella section of the valve but also the position of supporting, by the lower support member, of a shaft section of the valve is displaced downward after the lower end of the shaft section of the valve contacts the upper end surface of the guide, so that vibrating movement of the lower end of the shaft section is reduced to allow the chamfered surface to contact the opening edge. Then, the valve is inserted into the guide by a pressing member.

TECHNICAL FIELD

The present invention relates generally to methods and apparatus for inserting a valve into a valve guide.

BACKGROUND ART

Generally, the engine cylinder heads include intake/exhaust valves for opening and closing a passage for an air-fuel mixture flowing into a combustion chamber and exhaust gas flowing out of the combustion chamber. Theses valves each include a shaft section and an umbrella section provided at an end of the shaft section. Valve guide provided in the cylinder head has a small valve inserting hole, and thus, there is provided an extremely small gap between the shaft section and the inner surface of the valve inserting hole when the shaft section is to be inserted into the valve guide. Thus, in assembly lines, the valve insertion operation using a valve insertion apparatus and the like tends to be very difficult, and so there has been a great need for a valve insertion method and apparatus which allow the valve to be readily inserted into the valve guide.

For example, Japanese Patent Application Laid-Open Publication No. SHO-62-15032 (JP 62-015032 A) discloses a method and apparatus for inserting a valve into a valve guide by sucking in the valve. Japanese Patent Application Laid-Open Publication No. HEI-09-087043 (JP 09-087043 A) discloses vibrating a valve, and Japanese Patent Application Laid-Open Publication No. SHO-60-123323 (JP 60-123323 A) discloses a technique for inserting a desired part by vibrating the desired part.

The following lines describe the valve insertion method and apparatus disclosed in JP 62-015032 A, with reference toFIG. 6hereof. The valve101is grasped by a not-shown valve grasping device so as to be moved to a position over the valve guide102. Then, a valve sucking device103is abutted against a stem seal104mounted at the lower end of the valve guide102, and then the valve101is sucked by the sucking device103so that the valve101is inserted into an opening (valve inserting hole) of the valve guide102. After that, the valve101is inserted compulsorily into the valve guide102by means of a not-shown valve pressing unit.

FIG. 7shows a valve burning method disclosed in JP 09-087043 A. Holes114and115are formed in upper and lower beam sections112and113, respectively, which together constitute a setting jig111. Engine valve116of the valve116is inserted into these holes114and115with an umbrella section116located upside. Then, during a high-temperature heating (or burning) process, the setting jig111is vibrated to swing a shaft section118of the engine valve116, so that the engine valve116is prevented from remaining in a constant posture during the burning to avoid unwanted bending of the engine valve116.

FIG. 8shows a method disclosed in Patent Literature 3, which is designed to insert an automatic transmission spool into a valve body. Magazine having a plurality of spools inserted in advance in a plurality of holes formed therein is properly positioned relative to the valve body132and placed on the valve body132. Then, the magazine131and valve body132are vibrated by a vibrator133so that the spools are caused, by the vibration, to move from the holes of the magazine131into respective inserting holes formed in the valve body132.

However, with the valve insertion method disclosed in JP 62-015032 A and shown inFIG. 6here, the stem seal104may be damaged when the valve sucking device103is abutted against the stem seal104provided at the lower end of the valve guide102, the valve guide102may wear and deform by the valve sucking device103directly abutting against the valve guide102if the stem seal104is damaged, and a portion of the valve sucking device103to be abutted against the stem seal104may wear by being abutted against the stem seal104a plurality of times. Further, big sucking sound generated by the valve sucking device103would degrade the working environment. Further, because the valve sucking device103requires a sucking power source, such as a vacuum pump, the apparatus would become complicated in construction.

Further, with the method disclosed in JP 09-087043 A, where the shaft section118of the engine valve116is caused to swing by vibration during the burning in order to prevent unwanted bending of the engine valve116, the insertion of the engine valve116into the valve guide tends to become difficult because there is provided no means for appropriately reducing the vibration of the shaft section118.

Furthermore, with the insertion method disclosed in JP 60-123323 A, where the magazine131and valve body132are vibrated to cause the spools to be inserted, by their own weight, into the respective inserting holes formed in the valve body132, any of the spools may sometimes fail to be inserted into the inserting hole in the corresponding valve body132due to a dimension error between the hole in the magazine131and the inserting hole in the valve body132.

DISCLOSURE OF THE INVENTION

In view of the foregoing, it is an object of the present invention to provide a method and apparatus for inserting a valve into a valve guide reliably and easily by use of a simple construction without causing unwanted wear, deformation and damage of component parts.

In order to accomplish the above-mentioned object, the present invention provides an improved method for inserting a valve, having a shaft section and an umbrella section provided at one end of the shaft section, into a valve inserting hole of a valve guide provided in a cylinder head of an engine, which method comprises the steps of: supporting a surface, adjacent to the shaft section, of the umbrella section by an upper support member and supporting the shaft section of the valve with a gap left therebetween by a lower support member disposed beneath the upper support member; lowering, by an elevator device, the upper and lower support members, supporting the valve, together toward the valve guide with at least the lower support member of the upper and lower support members vibrated by a vibrating device; when a lower end of the valve has been brought into contact with the opening edge of a valve inserting hole of the valve guide as a result of lowering, by the elevator device, of the upper and lower support members, pressing the valve into the valve inserting hole by a pressing member; and when the lower end of the valve has failed to be brought into contact with the opening edge of the valve inserting hole of the valve guide as the result of lowering, by the elevator device, of the upper and lower support members, further lowering the upper and lower support members after the lower end of the shaft section contacts an upper end surface of the valve guide, to thereby not only cause the upper support member to gradually move away from the umbrella section but also cause a position of supporting, by the lower support member, of the shaft section to be displaced downward so that vibrating movement of the lower end of the shaft section, caused by at least the lower support member being vibrated by the vibrating device, is reduced and thus the lower end of the valve comes to contact the opening edge of the valve inserting hole; and pressing the valve into the valve inserting hole by the pressing member.

As the vibrating device vibrates at least the lower support member of the upper and lower support members, the shaft section of the valve is caused, through the vibration by the vibrating device, to swing, rotate about its own axis and move on and along the respective inner surfaces of the upper and lower support members supporting the valve (such swing, rotation and movement along the inner surfaces will be collectively referred to as “valve movement”).

When the lower end of the valve has been brought into contact with the opening edge of the valve inserting hole of the valve guide as the result of the lowering, by the elevator device, of the upper and lower support members with at least the lower support member vibrated by the vibrating device, the valve is pressed into the valve inserting hole by the pressing member.

If the lower end of the valve has failed to be brought into contact with the opening edge of the valve inserting hole of the valve guide as the result of lowering, the upper and lower support members are further lowered after the lower end of the shaft section contacts the upper end surface of the valve guide. Consequently, not only the upper support member gradually moves away from the surface, adjacent the shaft section, of the umbrella section, but also the position of supporting, by the lower support member, of the shaft section (i.e., the position at which the shaft section is supported by the lower support member) is displaced downward so that vibrating movement of the lower end of the shaft section, caused by at least the lower support member being vibrated by the vibrating device, is reduced while vibrating movement of the umbrella section gradually gets greater, and thus, the lower end of the valve comes to contact the opening edge of the valve inserting hole. Then, the valve is pressed into the valve inserting hole by the pressing member.

Once the lower end of the valve comes to contact with the opening edge of the valve inserting hole, the lower end of the shaft section can be automatically centered relative to the valve inserting hole by virtue of the above-mentioned valve movement and thus can be inserted into the inlet of the valve inserting hole. In this condition, the pressing member compulsorily presses the valve into a predetermined position of the valve inserting hole. Namely, the present invention can readily effect centering of the valve relative to the valve inserting hole through the vibration of the valve and thereby insert the valve into the valve inserting hole with an increased ease and reliability as compared to the conventionally-known techniques.

Further, the present invention can eliminate the need for compulsorily applying external pressure to the valve as done in the conventionally-known techniques using air suction of a valve, and the present invention allows the lower end of the valve to be centered relative to the valve inserting valve using the weight of the valve alone. As a result, the present invention can avoid unwanted wear, deformation, damage, etc. of the valve, valve guide, stem seal, etc. and thereby achieve appropriate valve assembly work.

According to another aspect of the present invention, there is provided an improved apparatus for inserting a valve, having a shaft section and an umbrella section provided at one end of the shaft section, into a valve guide, which comprises: a table for placing thereon a cylinder head having the valve guide; a valve grasping device including an upper support member for supporting a surface, adjacent to the shaft section, of the umbrella section and a lower support member disposed beneath the upper support member for supporting the shaft section with a gap left therebetween; an elevator device for moving the valve grasping device in an upward/downward direction; a vibrating device for vibrating at least the lower support member of the upper and lower support members; and a pressing member for compulsorily pressing the valve into the valve guide. Here, the valve grasping device is lowered, via the elevator device, toward the valve guide with at least the lower support member vibrated by the vibrating device. When the lower end of the valve has been brought into contact with the opening edge of a valve inserting hole of the valve guide as a result of lowering, by the elevator device, of the grasping device with at least the lower support member vibrated by the vibrating device, the valve is pressed into the valve inserting hole by the pressing member. When the lower end of the valve has failed to be brought into contact with the opening edge of the valve inserting hole of the valve guide as the result of lowering, by the elevator device, of the upper and lower support members, the valve grasping device is further lowered after the lower end of the shaft section contacts an upper end surface of the valve guide, to thereby not only cause the upper support member to gradually move away from the umbrella section but also cause a position of supporting, by the lower support member, of the shaft section to be displaced downward so that vibrating movement of the lower end of the shaft section, caused by at least the lower support member being vibrated by the vibrating device, is reduced to allow the lower end of the valve to come to contact the opening edge of the valve inserting hole.

As the vibrating device vibrates at least the lower support member of the upper and lower support members, the shaft section of the valve is caused, through the vibration by the vibrating device, to swing, rotate about its axis and move along the inner surfaces of the upper and lower support members supporting the valve (“valve movement”).

When the lower end of the valve has been brought into contact with the opening edge of the valve inserting hole of the valve guide as the result of the lowering, by the elevator device, of the upper and lower support members with at least the lower support member vibrated by the vibrating device, the valve is pressed into the valve inserting hole by the pressing member.

If the lower end of the valve has failed to be brought into contact with the opening edge of the valve inserting hole of the valve guide as the result of lowering, the upper and lower support members are further lowered after the lower end of the shaft section contacts the upper end surface of the valve guide. Consequently, not only the upper support member gradually moves away from the surface, adjacent the shaft section, of the umbrella section, but also the position of supporting, by the lower support member, of the shaft section is displaced downward so that vibrating movement of the lower end of the shaft section, caused by at least the lower support member being vibrated by the vibrating device, is reduced while vibrating movement of the umbrella section gradually gets greater, and thus, the lower end of the valve comes to contact the opening edge of the valve inserting hole. Then, the valve is pressed into the valve inserting hole by the pressing member.

Once the lower end of the valve comes to contact the opening edge of the valve inserting hole, the lower end of the shaft section is automatically centered relative to the valve inserting hole by virtue of the above-mentioned valve movement and thus can be inserted into the inlet of the valve inserting hole. In this condition, the pressing member compulsorily presses the valve a predetermined position of the valve inserting hole.

Thus, by only vibrating the valve via at least the lower support member vibrated by the vibrating device and lowering the upper and lower support members, the valve can be automatically centered relative to the valve inserting hole. As a consequence, the apparatus of the present invention can readily and reliably insert the valve into the valve inserting hole with a simple construction, including the conventional valve grasping device, elevator, vibrating device and pressing member similar to those heretofore employed in assembly apparatus, without a need for special devices designed for valve insertion.

Preferably, in the present invention, the shaft section has a chamfered surface formed in the lower end thereof, and the chamfered surface is brought into contact with the opening edge of the valve inserting hole as the upper and lower support members are lowered by the elevator device. With such a chamfered surface, the centering of the valve relative to the valve inserting hole can be facilitated even further, so that the valve can be inserted into the valve guide even more easily.

BEST MODE FOR CARRYING OUT THE INVENTION

Reference is now made toFIG. 1showing, in partially section, a valve insertion apparatus according to an embodiment of the present invention, where a cylinder head11of an engine is shown in section.

The valve insertion apparatus10includes: a slanted table15for appropriately positioning and placing thereon the cylinder head11to insert a plurality of valves13into corresponding valve guides12provided in the engine cylinder head11; a valve grasping device16for grasping the plurality of valves13; an arm17provided as an elevator on a robot (not shown) for moving the valve grasping device16in an upward/downward direction; a plurality of valve pressing devices18mounted over an upper portion of the valve grasping device16for compulsorily pressing the valves12; a vibrating device19mounted to the valve grasping device16; and stem seals21provided on lower end portions of individual ones of the valve guides12.

The cylinder head11has a surface11ato be abutted against a cylinder block and a surface11bto be covered with a head cover, and the cylinder head11is placed on the slanted table15with the surface11afacing upward and the surface11bfacing downward. Further, the cylinder head11is positioned relative to the table15by means of pins (not shown).

Each of the valve guides12is a component part fitted in the cylinder head11and has a valve inserting hole12aformed for insertion therein one of the valves13.

Each of the valves13has a shaft section13aand an umbrella section13bformed integrally with an end of the shaft section13a, and the valve13is supported by the valve grasping device16with the umbrella section13blocated upwardly of the shaft section13a.

The vibrating device19generates vibration of 273 Hz using air pressure, to thereby vibrate the valve grasping device16and hence the valves13. In the figure, each of the valves13is in a standby position immediately above the corresponding valve guide12with the axis of the valve13vertically aligned with the axis of the inserting hole12a.

FIG. 2is a front view showing principal sections of the valve insertion apparatus16. As shown, the valve insertion apparatus16includes an upper support member25, and a lower support member26disposed in contact with the lower surface of the upper support member25. The upper support member25supports the umbrella section13bof each of the valves13, while the lower support member26supports the shaft section13aof each of the valves13.

Air-pressure type cylinder devices28are mounted over the valve insertion apparatus16in corresponding relation to the valves13and located over the corresponding valves13. Each of the cylinder devices28has a rod31, and a pressing member32for pressing a surface13cof the umbrella section13bis provided at the distal end of the rod31.

Each of the valve pressing devices18includes the cylinder device28, a piston (not shown) axially movably provided in the cylinder device28, the rod31attached to the piston, and the pressing member32provided at the distal end of the rod31.

The valve grasping device16has a side plate33, to which are mounted the above-mentioned upper and lower support members25and26and vibrating device19.

FIGS. 3A-3Care views explanatory of details of the valves13and upper and lower support members25and26.

InFIG. 3A, the upper support member25includes a horizontal plate-shaped support body section25A and a vertical section25B extending vertically downward from the lower end of the support body section25A, and the lower support member26is disposed in contact with the lower surface of the vertical section25B. Namely, the lower support member26is disposed in spaced-apart relation to the lower surface of the support body section25A.

Each of the valves13is supported at an underside surface13dof the umbrella section13bfacing the shaft section13a, so that it is hung substantially vertically over the corresponding valve guide12.

Each of the valves13has an end surface13eof the shaft section13a, an annular groove13fformed immediately above the end surface13efor receiving an end portion of a valve spring, and a chamfered surface13gformed in the outer periphery of the end surface13e.

FIG. 3Bis a sectional view taken along the b-b line ofFIG. 3A. The upper support member25includes a first upper member35, and a second upper member36disposed in opposed relation to the first upper member35. The first upper member35has a flat inner surface35a, and the second upper member36has an inner surface36arecessed in a triangular or V sectional shape to form a V-shaped groove36b.

The umbrella section13bof each of the valves13is supported by an upper edge35cof the inner surface35aof the first upper member35and upper edges36cand36dof the V-shaped groove36bof the second upper member36. Reference numerals41,42and43indicate points of the upper edges35c,36cand36dwhich the underside surface13dof the umbrella section13bcontacts; in this way, the umbrella section13bof each of the valves13is supported at the three points41,42and43. Further,36eand36findicate slanted inner surfaces of the V-shaped groove36b. Gap C1is provided between each of the slanted inner surfaces36eand36fand the shaft section13a, and between the inner surface35aof the first upper member35and the shaft section13a.

FIG. 3Cis a sectional view taken along the c-c line ofFIG. 3A. The lower support member26includes a first lower member45, and a second lower member46disposed in opposed relation to the first lower member45. The first lower member45has an inner surface45arecessed in a triangular or V sectional shape to form a V-shaped groove45b, while the second lower member46has an inner surface46arecessed in a triangular or V sectional shape to form a V-shaped groove46b.

Gap C2is provided between each of slanted inner surfaces45eand45fof the V-shaped groove45aof the first lower member45and the shaft section13a, and between each of slanted inner surfaces46eand46fof the V-shaped groove46aof the second lower member46and the shaft section13a.

The following paragraphs describe behavior of the valve insertion apparatus10constructed in the above-described manner.

InFIG. 3A, only the lower support member26or both of the upper and lower support members25and26are vibrated by the vibrating device19(seeFIG. 2) with the valves13positioned over the corresponding valve inserting holes12aof the valve guide12, so that the each of the valves13swings to both sides of a vertical line48. More specifically, the valve13is caused, through the vibration by the vibrating device19to swing, rotate about its own axis and move on and along the respective inner surfaces of the upper and lower support members25and26supporting the valve13.

Then, the valve grasping device16is lowered by the arm17of the robot (seeFIG. 1). If, at that time, the chamfered surface13gof each of the valves13has been brought into contact with an upper-end opening edge12cof the valve inserting hole12aof the corresponding valve guide12, then an end portion13jof the shaft section13acan be automatically led into the valve inserting hole12a. Therefore, the first and second upper members35and36of the valve grasping device16are moved away from each other and likewise the first and second lower members45and46are moved away from each other, by means of not-shown drive devices, to release the grasping of each of the valves13. Then, each of the valve pressing devices18shown inFIGS. 1 and 2is activated to cause the corresponding valve13to be inserted into a predetermined position of the corresponding valve inserting hole12aby means of the pressing member32. Whether or not the valve13has been inserted into the predetermined position is detected via a not-shown sensor.

In case the chamfered surface13gof the valve13has failed to be brought into contact with the upper-end opening edge12cof the valve inserting hole12aof the corresponding valve guide12, the following steps are performed.

FIGS. 4A-4Care views explanatory of the behavior of the valve insertion apparatus10. More specifically,FIG. 4Ashows a state if the valve13has failed to be brought into contact with the upper-end opening edge12cof the valve inserting hole12aof the corresponding valve guide12. Namely, inFIG. 4A, the end surface13eof the valve13has been brought into contact with an upper end surface12b, not the opening edge12c, of the corresponding valve guide12. In the figure, the valve48is shown as swinging to both sides of the vertical line48by at least one of the upper and lower support members25and26being vibrated by the vibrating device19(seeFIG. 2).

In this state, the valve13vibrates about a point near the underside surface13dof the umbrella section13bsupported by the upper support member25; more specifically, portions at and around the end surface13eof the shaft section13aswing more than portions at and around the umbrella section13b. In this condition, the valve grasping device16is further lowered as indicated by a white arrow.

FIG. 4Bshows the valve grasping device16having been lowered from the position shown inFIG. 4A. In this state, the upper support member25is located away from the underside surface13dof the umbrella section13b, and thus, the shaft section13aof the valve13is supported by the upper and lower support members25and26with some gap left between the shaft section13aand the support members25and26while vibrating through vibration of the lower support member26, so that the valve13rests, by its own weight, on the upper end surface12bof the valve guide12. In that state, the valve13vibrates about a point between the upper and lower support members25and26in such a manner that portions at and around the end surface13eof the shaft section13aswing less than in the state ofFIG. 4A; this is because, in the state ofFIG. 4B, the shaft section13ais supported by the lower support member26at a position lower than inFIG. 4A; namely, the position of supporting, by the lower support member26, of the valve13has been displaced downwardly.

FIG. 4Cshows the valve grasping device16having been further lowered from the position shown inFIG. 14B. In this state, the center of the vibration of the valve13is located at a point between the upper and lower support members25and26lower than that inFIG. 4B, so that portions at and around the end surface13eof the shaft section13aswing less than in the state ofFIG. 4B.

FIGS. 5A and 5Bare views further explanatory of the behavior of the valve insertion apparatus10.

As the valve grasping device16is further lowered, the swinging movement of portions at and around the end surface13eof the shaft section13abecome smaller so that the chamfered surface13gof the valve13is brought into contact with the upper-end opening edge12cof the valve inserting hole12aof the corresponding valve guide12, as shown inFIG. 5A.

Then, as the chamfered surface13gmoves on and along the upper-end opening edge12c, the valve13is automatically centered by the axis51of the valve13gradually approaching or agreeing with the axis52(coinciding with the vertical line48ofFIG. 4C). In this way, the end portion13jof the shaft section13acan be automatically led into the valve inserting hole12a, as shown inFIG. 5B.

Thereafter, once the valve grasping device16is lowered to a predetermined position, the vibration, by the vibrating device19(seeFIG. 2), of the valve grasping device16is terminated. Then, the first and second upper members35and36of the valve grasping device16are further moved away from each other and likewise the first and second lower members45and46are further moved away from each other, by means of the not-shown drive devices, so that the valve13is released from the grasping by the grasping device16. Then, the valve pressing device18is activated so that the valve13is inserted into a predetermined position within the valve inserting hole12avia the pressing member32.

As having been described above with primary reference toFIGS. 2,4and5, the valve insertion method of the present invention is constructed to insert the valve13, having the shaft section13aand the umbrella section13bprovided at one end of the shaft section13a, into the valve guide12provided in the engine cylinder head11. More specifically, according to the inventive valve insertion method, the upper support member25supports the underside surface13dof the umbrella section13bfor transfer of the valve13, and the lower support member26disposed beneath the upper support member25supports the shaft section13awith the gap C2therebetween. Then, the upper and lower support members25and26, supporting the valve13, are together lowered toward the valve guide12with at least one of the support members25and26and hence the valve13vibrated by the vibrating device19. If the lower end, more specifically the chamfered surface13g, of the valve13has been brought into contact with the opening edge12cof the valve inserting hole12aof the valve guide12as a result of the lowering of the upper and lower support members25and26, the valve13is pressed via the pressing member32into the valve inserting hole12a. If, on the other hand, the lower-end chamfered surface13g, of the valve13has failed to be brought into contact with the opening edge12cof the valve inserting hole12aof the valve guide12as a result of the lowering of the upper and lower support members25and26, the upper and lower support members25and26are further lowered after the lower end of the shaft section13acontacts the upper end surface of the valve guide, so that the upper support member25is gradually moved away from the umbrella section13band the position the shaft section13ais supported (i.e., the position of supporting, of the shaft section13a) by the lower support member26is displaced downward. As a consequence, the swinging or vibrating movement of the lower end of the shaft section13ais reduced, and thus, the lower end or chamfered surface13gof the valve13comes to contact the opening edge12cof the valve inserting hole12a. Then, the valve13is pressed via the pressing member32into the valve inserting hole12a. Namely, vibrating via the vibrating device19the valve13on the upper end surface of the valve guide12can automatically center the valve13relative to the valve inserting hole12a. As a result, the inventive method can insert the valve13into the valve inserting hole12awith an increased ease and reliability as compared to the conventional counterparts.

Further, the valve insertion method of the present invention can eliminate the need for compulsorily applying external pressure to the valve as done in the conventional techniques using air suction of a valve, and the valve insertion method of the present invention allows the lower end of the valve13to be centered relative to the valve inserting valve12ausing only the weight of the valve13. As a result, the valve insertion method of the present invention can avoid unwanted wear, deformation, damage, etc. of the valve13, valve guide12, stem seal21, etc. and thereby achieve appropriate valve assembling work.

Further, with the valve insertion method of the present invention, where the chamfered surface13gis formed at the lower end of the shaft section13aand is brought into contact with the opening edge12cof the valve inserting edge12c, the cooperative action between the chamfered surface13gand the opening edge12callows the lower end of the shaft section13ato be readily centered relative to valve inserting hole12a, so that the valve13can be inserted into the valve guide12of the valve with an increased ease and reliability.

Further, the valve insertion apparatus10of the present invention is constructed to insert the valve13into the valve guide12includes: the table15for placing thereon the cylinder head having the valve guide12; the upper support member25for supporting the underside surface13dof the umbrella section13bfor transfer of the valve13; the valve grasping device16including the lower support member26disposed beneath the upper support member25for supporting the shaft section13awith the gap C2therebetween; the robot arm17functioning as an elevator device for moving the valve grasping device16in the upward/downward direction, the vibrating device19for vibrating at least one of the upper and lower support members25and26; and the pressing member32for compulsorily pressing the valve13into the valve guide12. In the valve insertion apparatus, the valve grasping device26is lowered, via the arm17, toward the valve guide12with at least the lower support member26of the upper and lower support members25and26vibrated by the vibrating device19. If the lower end of the valve13has been brought into contact with the opening edge12cof the valve inserting hole12aof the valve guide12as a result of the lowering of the valve grasping device26, the valve13is pressed via the pressing member32into the valve inserting hole12a.

In case the lower end of the valve13has failed to be brought into contact with the opening edge of the valve inserting hole of the valve guide12, the valve grasping device16is further lowered after the lower end of the shaft section contacts an upper end surface of the valve guide12, to thereby not only cause the upper support member25to gradually move away from the umbrella section13bbut also cause the position of supporting, by the lower support member, of the shaft section to be displaced downward so that the vibrating movement of the lower end of the shaft section, caused by at least the lower support member26being vibrated by the vibrating device19, is reduced to allow the lower end of the valve to come to contact the opening edge of the valve inserting hole12a.

Thus, by only vibrating the valve13by the vibrating device19via at least the lower support member26and lowering the upper and lower support members25and26, the valve13can be automatically centered relative to the valve inserting hole12a. As a consequence, the valve insertion apparatus10of the present invention can readily and reliably insert the valve13into the valve inserting hole12awith a simple construction, including the conventional-type valve grasping device16, arm17functioning as the elevator, vibrating device19and pressing member32similar to those employed in the conventional assembly apparatus.

Whereas the preferred embodiment has been described above in relation to the case where the lower support member26is disposed in contact with the lower surface of the upper support member25as shown inFIG. 2, the lower support member26may be disposed beneath the upper support member25.

Further, in the aforementioned embodiment, the second upper member36has the V-shaped groove36b, and the umbrella section13bof the valve13is supported at three points by the first upper member35and second upper member36. However, the present invention is not so limited; for example, a pair of the first upper members35may be disposed in opposed relation to each other, and the valve13may be disposed between these first upper members35so that the umbrella section13bis supported at two points by the first upper members35.

If the lower end of the valve13has been brought into contact with the opening edge12cof the valve inserting hole12aof the valve guide12as a result of the lowering of the valve grasping device26, the valve13is pressed via the pressing member32into the valve inserting hole12a, as described above in relation toFIG. 3A. Alternatively, in this case, the upper and lower support members25and26may be further together lowered toward a predetermined position near the valve guide12as when the lower end of the valve13has failed to be brought into contact with the opening edge12cof the valve inserting hole12a, after which the valve13may be pressed via the pressing member32into the valve inserting hole12a.

INDUSTRIAL APPLICABILITY

The valve insertion apparatus and method of present invention are particularly useful for assembly of engine intake and exhaust valves.