GB2283564A

GB2283564A - A vehicle headlight

Info

Publication number: GB2283564A
Application number: GB9422146A
Authority: GB
Inventors: Hirohisa Deguchi; Hitoshi Hirose
Original assignee: Koito Manufacturing Co Ltd
Current assignee: Koito Manufacturing Co Ltd
Priority date: 1993-11-04
Filing date: 1994-11-02
Publication date: 1995-05-10
Anticipated expiration: 2014-11-02
Also published as: DE4439529A1; GB2283564B; DE4439529C2; GB9422146D0; JPH07186816A; JP2787420B2

Abstract

A light-beam aiming device for headlamps which is for tilting a reflector 3 to tilt a light-beam includes a worm gear 61 rotated by a motor 59 and a worm wheel 9 in mesh with the worm. The worm wheel 9 has an axially extending hole of which the inner surface has a screw thread 12, and a radially extending flange 10. A shaft member 26 includes a holder shaft 27 and an adjusting shaft 31. The holder shaft 27 has a screw thread 28 which engages the worm wheel. The adjusting shaft is rotatably supported by the holder shaft and coupled with the reflector. A holder 21 is fitted on the shaft member and slidably contacts the worm wheel. A casing body 6 is provided for fixing the holder. The casing has contact means 18a slidably contacting the worm wheel, wherein the worm wheel 9 is rotatably held between the holder and the casing. The shaft member 26 is axially moved upon rotation of the worm wheel 9. <IMAGE>

Description

LIGHT-BEAM AIMING DEVICE FOR HEADLAMPS In light-beam aiming devices for headlamps, it is required that a shaft member is axially movable but not rotatable about its axis. Japanese Patent Application No.

Hei. 5-216868, for example, proposes one example of such a shaft member. In this technique, a case containing a worm wheel and a shaft member is divided into two cases. A supporting member having a protrusion on the inner surface thereof is fastened to the first case. A long narrow indentation is formed over the entire circumference of the worm wheel. The protrusion of the support member slidably engages the narrow indentation of the worm wheel. With this structure, the worm wheel is rotatable with respect to the case but is immovable in the axial direction.

The shaft member is provided with a sliding protrusion. The protrusion of the shaft member slidably engages with a guide groove longitudinally formed in the second case. With this structure, the shaft member is longitudinally movable but is not rotatable.

The proposed technique as described above which allows the worm wheel to be rotatable but prohibits the worm wheel from moving in the axial direction by bringing the protrusion of the support member into slidable contact with the indentation, is still disadvantageous in that poor working efficiency and unsatisfactory support are secured.

That is, to make the protrusion-indentation engagement, the worm wheel must be fitted to the support member. A large force is required to fit the worm wheel to the support member. This deteriorates the assembly working efficiency.

In fitting the worm wheel to the support member, the protrusion of the support member hinders the fitting work, as a matter of course. This limits the increase of the height of the protrusion, and hence the increase of the depth of the indentation. In the resultant engaging structure, there is a limit in enhancing the capability of preventing the worm wheel from moving in the axial direction.

To assemble the first and second cases, the first case and the second case must be coupled with each other while the slide protrusion of the shaft member supported by the worm wheel, which is also supported by the first case, is positioned to the guide groove of the second case. The assembling work progressing concurrently with the positioning of the portions concealed within the case is inevitably inefficient.

According to a first aspect of the present invention, there is provided a light-beam aiming device for a headlamp for tilting a tilted member so that a light-beam axis is tilted, the device comprising a casing body; a worm rotatably supported in the casing body; means for rotating the worm; a worm wheel rotatably supported in the casing body and engaging with the worm; a shaft member having a coupling for engagement with the tilted member, the shaft member comprising a screw thread formed on an outer surface thereof, and being screwed to the worm wheel; and a holder member fixedly supported within the casing body coaxially with the shaft member, the holder member comprising a contact section slidably contacting to the worm wheel and an engaging section engaging with the shaft member so that the shaft member is slidable in an axial direction relatively to the holder member.

The worm wheel is rotatably held between the casing body and the holder, so that the shaft member is supported by the case member in a manner that it is rotatable but axially immovable. The working for its holding is efficient, and a reliable immovability of the worm wheel in the axial direction is achieved.

According to a second aspect of the present invention, there is provided a method for assembling a light-beam aiming device, comprising steps of preparing a casing body, a shaft member, a worm wheel and a holder member; forming a subassembly by threadably engaging the worm wheel with the shaft member and thereafter engaging the holder member onto the shaft member and the worm wheel; and securing the subassembly to the casing body.

In the accompanying drawings: Fig. 1 is a vertical sectional view showing an outline of a headlamp levelling mechanism according to a first embodiment of the present invention; Fig. 2 is an enlarged vertical view showing a key portion of the levelling mechanism; Fig. 3 is a section taken on the line III-III in Fig.

2; Fig. 4 is a section taken on the line IV-IV in Fig. 2; Fig. 5 is an exploded sectional view showing a worm wheel, a shaft member, and a holder; Fig. 6 is a partially exploded sectional view showing the worm wheel, the shaft member, and the holder; Fig. 7 is a sectional view showing the assembly of the worm wheel, the shaft member, and the holder, and a part of a back case which supports a front case and an aiming rod of a device according to a first embodiment of the invention; Fig. 8 is a rear view showing the holder; Fig. 9 is a rear view showing a key portion of the front case; Fig. 10 is an enlarged view showing the aiming rod when viewed in the direction of an arrow X in Fig. 7; Fig. 11 is an enlarged view showing the aiming rod when viewed in the direction of an arrow XI in Fig. 7;; Fig. 12 is an enlarged view showing the back case when viewed in the direction of an arrow XII in Fig. 7; Fig. 13 is an enlarged cross sectional view showing a state that the aiming rod is turned in the invention.

Fig. 14 is a vertical sectional view schematically showing a head lamp levelling device according to a second embodiment of the present invention; Fig. 15 is an enlarged vertical sectional view showing a key portion of the head lamp levelling device; Fig. 16 is a section taken on the line XVI-XVI in Fig.

15; Fig. 17 is a section taken on the line XVII-XVII in Fig. 15; Fig. 18 is a plan view showing the head lamp levelling device; Fig. 19 is a rear view showing the head lamp levelling device when the back case is removed; Fig. 20 is a rear view showing the front case; Fig. 21 is a section taken on the line XXI-XXI in Fig.

20; Fig. 22 is a section taken on the line XXII-XXII in Fig. 20; Fig. 23 is a section taken on the line XXIII-XXIII in Fig. 20; Fig. 24 is a section taken on the line XXIV-XXIV in Fig. 20; Fig. 25 is a cross sectional view showing a worm wheel, a holder shaft, and a holder, separately; Fig. 26 is a cross sectional view showing the worm wheel, a shaft member, and the holder, separately; Fig. 27 is a cross sectional view showing an assemble of the worm wheel, the shaft member, and the holder, and the front case and a part of the back case supporting an aiming rod according to the second embodiment of the invention; Fig. 28 is a rear view showing the holder shaft; Fig. 29 is a rear view showing the holder; Fig. 30 is an enlarged view showing the aiming rod when viewed in the direction of an arrow XXX in Fig. 27; ; Fig. 31 is an enlarged view showing the aiming rod when viewed in the direction of an arrow XXXI in Fig. 27; Fig. 32 is an enlarged view showing the aiming rod when viewed in the direction of an arrow XXXII in Fig. 27; Fig. 33 is an enlarged, perspective view showing the aiming rod; and Fig. 34 is an enlarged, cross sectional view showing a key portion when the aiming rod is turned.

As shown in Fig. 1, a headlamp 1 includes a lamp body 2, a reflector 3 supported by the lamp body 2 so that it may be swung upwardly and downwardly, and a lens 4 covering the front opening of the lamp body 2.

In this embodiment, the reflector 3 serves as a tilting member for varying the aiming direction of light beams when it is tilted. Alternatively, a lamp unit in which a reflector and a light source are disposed in a space defined by the lamp body and the lens, may be the tilting member. In this case, the lamp unit is supported by a car body in a tiltable fashion.

As shown in Figs. 1-4, a headlamp levelling mechanism 5 firmly attached to a car body (not shown) is provided with a casing body 6 made of synthetic resin, which casing body consists of a front case 7 and a back case 8. These cases are coupled together into the casing body 6.

As best shown in Figs. 5-7, a worm wheel 9 is rotatably supported by the casing body 6. However, the worm wheel 9 is immovable axially back and forth with respect to the casing body 6. The worm wheel 9, made of synthetic resin, is substantially tubular in shape. A flange 10 outwardly extends from the rear end of the worm wheel 9 and gear teeth 11 are formed on the outer surface of the flange 10. The flange 10 is integrally formed with the worm wheel in this embodiment. However, the flange may be provided separately from the worm wheel if desired.

A screw thread 12 is formed in the inner surface of the flange 10. An annular recess 13 is formed in the rear end face of the flange 10. The front case 7 includes a front wall 14 and a side wall 15 extending rearwardly from the circumferential edge of the front wall 14. An insertion hole 16 is formed in the front wall 14. A tubular portion 17 extends forwardly from the outer opening of the insertion hole 16. A support tube 18 extends towards the inner side from the inner opening of the insertion hole 16.

A flange 19 radially projects from a middle on the inner surface of the tubular portion 17. A stopper 19a protrudes rearwardly from the inner circumferential edge of the flange 19. As best shown in Figs. 7 and 9, mounting protrusions 20 protrude from the inner surface of the front wall 14 and fastening pins 20a protrude from the rear end faces of the respective mounting protrusions 20.

A holder 21 is fastened to the front wall 14. It includes a tubular main portion 22 made of synthetic resin.

A mounting portion 23 extends outward from the fore end part of the main portion 22. Mounting holes 23a are formed in the mounting portion 23. As best illustrated in Figs.

5, 6 and 8, guide notch 24 extends from the fore end part of the main portion 22. A guide groove 25 is formed in a part of the inner surface of the main portion 22, opposite to the guide notch 24 as best shown in Fig. 6.

The structure in which the worm wheel 9, supported by the front wall 14, is rotatable but immovable in the axial direction, will be described hereinafter.

The portion of the worm wheel 9, located on the fore side of the flange 10, is fitted into the support tube 18 of the front case 7. The rear end 18a of the support tube 18 is brought into contact with the front end face of the flange 10.

The fastening pins 20a of the mounting protrusions 20 of the front case 7 are inserted into the mounting holes 23a of the mounting portion 23 in a state that the front end 22a of the main portion 22 of the holder 21 slidably comes in contact with the annular recess 13 formed in the rear side of the flange 10 of the worm wheel 9. The portions of the fastening pins 20a, which protrude toward the rear side of the mounting portion 23, are caulked, so that the holder 21 is fastened to the front case 7. The front case 7 supports the worm wheel 9 rotatably but immovably in the axial direction so that the flange 10 of the worm wheel is nipped by the rear end 18a of the support tube 18 and the front end 22a of the main portion 22 of the holder 21.

A shaft member 26 includes a holder shaft 27 and an adjusting shaft 31. The holder shaft 27 is made of synthetic resin, is tubular in shape and has a screw thread 28 on the outer surface of the rear end portion thereof.

A pushing piece 29 and a guide protrusion 30, which are integral with the holder shaft 27, radially protrude from the rear end of the holder shaft 27 in the opposite directions. The adjusting shaft 31 is a metal rod-like member with a flange 32 at a location close to the rear end thereof. A portion 33 of the adjusting shaft 31, which ranges from the location of the flange 32 to the rear end of the adjusting shaft 31, serves as a slide coupling portion and has an oval cross section.

The first half of the left portion of the adjusting shaft 31 with respect to the flange 32 is a screw threaded portion 34. An engaging groove 35, formed around the adjusting shaft 31, is located just rearward from the right end of the screw threaded portion 34. The length of the adjusting shaft 31 between the rear end of the engaging groove 35 and the front face of the engaging groove 35 is substantially equal to the length of the center hole of the holder shaft 27. The adjusting shaft 31 is supported by the holder shaft 27 in a manner that it is movable in the axial direction but immovable in the rotational direction.

To support the adjusting shaft 31 by the holder shaft 27, the adjusting shaft 31 is inserted into the center hole of the holder shaft 27 from the rear side of the holder shaft.

A spring washer 36 is fitted to the holder shaft 27 from its front end, and a fixing circlip 37 is set in the engaging groove 35.

The shaft member 26 is formed so that the adjusting shaft 31 is supported by the holder shaft 27. The screw thread 28 of the holder shaft 27 is screwed to the screw thread 12 of the worm wheel 9. The guide protrusion 30 of the holder shaft 27 is slidably coupled with the guide groove 25 of the holder 21. The pushing piece 29 of the holder shaft 27 is slidably coupled with the holder 21.

With this structure, the shaft member 26 is axially movable upon rotation of the worm wheel 9. The top end part of the pushing piece 29 passes through the guide notch 24 and protrudes outside the holder 21 as shown in Fig. 6. The fore end part of the holder shaft 27 passes through the insertion hole 16 of the front case 7 and the tubular portion 17 thereof. The screw threaded portion 34 of the adjusting shaft 31 is screwed into a nut 38 supported at the turning end of the reflector 3.

The worm wheel 9, the holder 21, and the shaft member 26, thus assembled, constitute a subassembly. The subassembly is assembled to the front case 7, as shown in Fig. 7. When using this assembling method, the final assembling work is extremely simplified. Also in the transportation and storage before the assembling, the assembling method contributes to the labour saving and space saving.

The back case 8 is provided with a rear wall 39 and a side wall 40 extending forward from the rear wall 39. An insertion hole 41 is formed in the rear wall 39 at a location corresponding to the insertion hole 16 of the front case 7. The rear wall 39 is integral with a tubular portion 42 protruding forward from the front opening of the insertion hole 41 and another tubular portion 43 protruding from the rear opening thereof. An annular groove 44 is formed in the inner edge of the rear end of the rear tubular portion 43. A protecting wall 45 protrudes from the rear face of the side wall 40 in a state that it surrounds the tubular portion 43 with a great space therebetween. The protecting wall 45 includes a number of circumferentially spaced cutouts 46.

An aiming rod 47 includes a main body 48 made of synthetic resin and a crown gear part 49, made of metal, and located at the rear end part of the main body 48. The crown gear part 49 is formed, by an outsert molding, to be integral with the main body 48. The portion of the main body 48 except the crown gear part 49 is a tubular portion 50. The tubular portion 50 has a coupling hole 51 at the front end. The coupling hole 51 has an oval cross section.

The slide coupling portion 33 of the adjusting shaft 31 is inserted into the tubular portion 50 and is movable slidably but not rotatably.

Two pairs of slits 52a and 52b are formed in the tubular portion 50 such that one pair of upper slits 52a diverge from respective upper corners of the coupling hole 51, while the other pair of lower slits 52b diverge from respective lower corners of the coupling hole 51. A resilient engaging piece 53 is formed between the upper paired slits 52a. Another resilient engaging piece 53 is formed between the paired lower slits 52b. Engaging claws 54 respectively protrude from the outer surfaces of the portions of the resilient engaging pieces 53, which are close to the front end. The front faces 54a of the engaging claws 54 are tapered faces. The rear faces 54b are stopper faces directed perpendicular to the axial direction of the tubular portion 50. The base part 50a of the tubular portion 50 is larger in diameter than the remaining part thereof.

A projecting part 55, hexagonal in cross section, constitutes the rear part of the main body 48 when viewed with respect to the crown gear part 49. A cross-shape groove 56 is formed in the rear face of the projecting part 55. The crown gear part 49, made of metal, is shaped like a shallow cup formed by bending a circular plate forward along the circumferential edge thereof, and the upstanding side wall of the cup is cut out equidistantly therealong, thereby forming gear teeth.

The tubular portion 50 of the aiming rod 47 thus structured is inserted into the insertion hole 41 of the back case 8, from the rear side. During the insertion process, the engaging claws 54 are pressed by the tubular portions 43 and 42 and the inner surface of the insertion hole 41. As a result, the resilient engaging pieces 53 of the aiming rod 47 are flexed inwards. The insertion of the tubular portion 50 progresses, and when the engaging claws 54 leave the front end of the tubular portion 42, the resilient engaging pieces 53 are returned to their original states. The rear faces 54b of the engaging claws 54 engage the front end edge of the tubular portion 42, so that the aiming rod 47 is prevented from slipping out off the back case 8. The aiming rod 47 is rotatably supported by the back case 8.In this state, the front face of the base part 50a of the tubular portion 50 is brought into contact with the rear end of the tubular portion 43 in the rear part of the back case 8.

An 0-ring 58 is externally fitted into the base 50a of the tubular portion 50 of the aiming rod 47. When the aiming rod 47 is supported by the back case 8, it is positioned in the annular groove 44, which is formed in the inner face of the rear end of the tubular portion 43. The O-ring 58 thus mounted serves a water proof function.

When the front case 7 is coupled with the back case 8 with the rear opened face of the front case 7 abutting against the front opened face of the back case 8, the slide coupling portion 33 of the adjusting shaft 31 supported by the front case 7 is inserted into the coupling hole 51 of the aiming rod 47 so that the slide coupling portion 33 is axially movable but not rotatable.

A motor 59 is fastened within the casing body 6; and a pinion gear 60 is firmly attached to a rotary shaft 59a of the motor 59. A worm 61 is rotatably disposed within the casing body 6 such that the shaft of the worm 61 is in parallel with the shaft of the motor 59. The worm gear 61 engages with the worm wheel 9. A spur gear 62 integral with the worm gear 61 meshes with the pinion gear 60. With this structure, when the motor 59 is operated, the worm wheel 9 is turned.

A resistive sensor 63 comprises a moving rod 65, supported by a case 64, and which is movable forwardly and backwardly. Resistance of the resistive sensor 63 varies depending on a relative position of the moving rod 65 to the case 64. A spring means (not shown) constantly urges the moving rod 65 forward. The rear of the moving rod 65 of the resistive sensor 63 resiliently contacts the pushing piece 29 of the holder shaft 27 of the shaft member 26.

With this structure of the sensor, when the shaft member 26 moves forwards and backwards, the moving rod 65 of the resistive sensor 63 moves, and hence resistance of the resistive sensor 63 changes. Accordingly, it is possible to detect a current position of the shaft member 26 by detecting this resistance. An inclination angle of the reflector 3 may be detected using the detected position of the shaft member 26.

The initial aiming adjustment by the headlamp levelling mechanism 5 may be carried out by rotating the aiming rod 47. When the aiming rod 47 is turned, the adjusting shaft 31, the slide coupling portion 33 of which is slidably inserted into the coupling hole 51, is turned, and the screw threaded portion 34 thereof is screwed into and out of the nut 38 supported by the reflector 3. With the movement of the screw threaded portion 34, the distance between the part where the nut 38 of the reflector 3 is fixed and the lamp body 2 varies, so that the reflector 3 is tilted with respect to the lamp body 2. The aiming rod 47 is manually turned by a cross-shape screw driver, for example.

Reference numeral 66 designates cross-shape screw driver. An operator inserts the tip 66a of the screw driver 66 into the protecting wall 45 of the back case 8 through one of the cutouts 46 thereof. The tip 66a of the screw driver engages a gear tooth 57 of the crown gear part 49 of the aiming rod 47. In this state, the screw driver 66 is turned, so that the gear tooth 57 of the crown gear part 49 is advanced, and the aiming rod 47 is turned.

Since the protecting wall 45 includes the plural number of circumferentially spaced cutouts 46 through which an operation means, such as a screw driver, is inserted for the initial aiming adjustment, an operator can access the gear tooth for adjustment in a number of directions.

The projecting part 55 of the aiming rod 47 may be used for turning the aiming rod 47. By using a hexagonal wrench or by putting the tip of a cross-shape screw driver to the groove 56, the aiming rod 47 may be turned.

The levelling adjustment is carried out using the motor 59. When the motor shaft is turned, the worm wheel 9 is turned as mentioned above. With the turn of the worm wheel 9, the screw thread 28 is fed along the screw thread 12, so that the holder shaft 27 is moved forwards or backwards depending on the direction of the rotation of the worm wheel 9, and the adjusting shaft 31 is moved forwards or backwards. With the forwards or backwards movement of the adjusting shaft 31, the distance between the part where the nut 38 of the reflector 3 is fixed and the lamp body 2 varies, so that the reflector 3 is tilted with-respect to the lamp body 2.

Figs. 14-34 illustrate the illumination angle adjusting device according to a second embodiment of the invention. In the figure, like parts and components which are the same as those of the first embodiment are designated by the same reference numerals and a detailed description is omitted.

As shown in the figures, a head lamp levelling mechanism 67 is fastened to a car body, not shown. A case body 68 includes a front case 69 and a back case 70, both made of synthetic resin, are coupled to form the case body 68. The front case 69 is provided with a front wall 71 and a side wall 72 extending rearwards from the circumferential edge of the front wall 71. An insertion hole 73 is formed in the front wall 71. A tubular portion 74 projects out of the outside opening of the insertion hole 73. A support tube 75 protrudes from the inside of the insertion hole 73.

The rear end face of the support tube 75, is semispherical in cross section, and serves as a holder portion 75a.

A flange 76 extends inwards from the inner surface of the tubular portion 74. The flange 76 is located approximately in the middle of the tubular portion 74. A stopper 76a protrudes rearwards from the inner edge of the flange 76. Mounting protrusions 77 protrude from the inner surface of the front wall 71. Caulking pins 77a protrude rearwards from the back faces of the mounting protrusions 77. On the other hand, mounting protrusions 78 protrude from the inner surface of the front wall 71. Caulking pins 78a protrude rearwards from the back faces of the mounting protrusions 78.

Reference numeral 79 and 80 indicate worm gears protruding rearwards from horizontally separated locations on the inner surface of the front wall 71. These locations are substantially in the middle (as viewed in the vertical direction) on the inner surface of the front wall 71. The worm gears 79 and 80 are shaped like horizontally directed plates. Slits 81 and 82 of the worm gears 79 and 80 extend from the positions close to the bases (on the front wall 71 side) to the rear ends thereof, respectively. The slits 81 and 82 have substantially circular, large diameter portions 81a and 82a, located closer to the rear ends thereof, respectively. The rear portions of the slits 81 and 82 (as viewed with respect to the large diameter portions 81a and 82a) serve as introducing portions 81b and 82b, the distance between them being expanded gradually toward the rear.

Motor receiving portions 83 and 84 protrude rearward from horizontally separated locations on the lower part of the inner surface of the front wall 71. The motor receiving portions 83 and 84 are shaped like plates directed horizontally. Slits 85 and 86 of the motor receiving portions 83 and 84 extend from the positions closer to the bases (on the front wall 71 side) to the rear ends thereof, respectively. The slits 85 and 86 have substantially circular, large diameter portions 85a and 86a, located closer to the rear ends thereof, respectively.

The rear portions of the slits 85 and 86 (as viewed with respect to the large diameter portions 85a and 86a) serve as introducing portions 85b and 86b. The distance between them is gradually expanded toward the rear.

The rear end portion of the side wall 72 of the front case 69 is constructed with an inner wall 87 and an outer wall 88 located outside the inner wall 87. A fitting groove 89 is formed between the inner wall 87 and the outer wall 88. The width (as viewed longitudinally) of the outer wall 88 is substantially twice as long as that of the inner wall 87. Accordingly, the outer wall 88 extends to a point closer to the rear than the inner wall 87.

Slits 90 are formed at the four corners of the outer wall 88. The slits 90 longitudinally extend and reach the rear end. The outer wall 88 further includes rectangular engagement holes 91. A worm wheel 92 is rotatably supported by the case body 68 and immovable in the longitudinal direction. The worm wheel 92 is made of synthetic resin and substantially tubular in shape. A flange 93 extends from the rear end of the worm wheel 92.

The flange 93 with gear teeth 94 formed in the outer surface thereof forms a worm wheel.

A screw thread 95 is formed on the inner surface of the worm wheel 92. A ring-like groove 96 is formed on the rear end face of the flange 93. A holder 97 is fastened to the front case 69. A mounting part 99, integral with holder 97, extends outwards from the fore end portion of a tubular main portion 98 made of synthetic resin. Mounting holes 99a are formed in the mounting part 99. The rear opening edges 99b of the mounting holes 99a are tapered outward to have enlarged diameters.

A guide cut 100 ranges from the fore end part of the main portion 98 to the rear end thereof. A guide concavity 101, longitudinally extending, is formed in the portion of the inner surface of the main portion 98, where it confronts with the guide cut 100. The fore end of the main portion 98, half-sphere in cross section, serves as a holder portion 98a.

The worm wheel 92 is rotatably but axially immovably supported by the front case 69 in the following way. The fore end part of the worm wheel 92 (as viewed with respect to the flange 93 is inserted into the support tube 75 of the front case 69. The holder portion 75a of the support tube 75 abuts on the fore end of the flange 93. To fasten the holder 97 to the front case 69, the caulking pins 77a of the mounting protrusions 77 of the front case 69 are inserted into the mounting holes 99a of the mounting part 99, in a state that the holder portion 98a of the main portion 98 slidably engages the ring-like groove 96 formed in the rear surface of the flange 93. The portions of the caulking pins 77a, which protrude to the rear side of the mounting part 99, are caulked.The worm wheel 92 is rotatably but axially immovably supported by the front case 69 in a state that the flange 93 of the worm wheel 92 is nipped by the holder portion 75a of the support tube 75 of the front case 69 and the holder portion 98a of the main portion 98.

The holder portion 75a and the holder portion 98a nipping the flange 93 of the worm wheel 92 are shaped semispherically in cross section. This half-sphere shape of those portions ensures a smooth rotation of the worm wheel 92 with small frictional resistance. The rear opening edges 99b of the mounting holes 99a of the holder 97 are tapered outward to have enlarged diameters. Molten parts of the caulking pins 77a fill in those tapered portions, thereby eliminating a play of the holder 97 after it is assembled.

A shaft member 102 comprises a tubular holder shaft and an adjusting shaft rotatably supported in the holder shaft. A holder shaft 103 is made of synthetic resin. The outer surface of the rear part of the holder shaft 103 is threaded to form a screw thread part 104. The rear end of which is outwardly expanded to form a pressure part 105.

A guide protrusion 106 protrudes outwardly from the holder shaft, diametrically opposed to the location where the pressure part 105 is formed. A plurality of axially extending cuts 108 are formed in the inner surface of the holder shaft 103.

An adjusting shaft 109 is a rod made of metal, and a rear end portion of the adjusting shaft 109 is radially expanded to form a flange 110. A rear part of the adjusting shaft, behind the flange 110, is shaped with an oval cross section. This oval rear part serves as a slide coupling part.

The first half 112 of a fore part of the adjusting shaft, in front of the flange 110, forms a screw threaded shaft. An engaging groove 113 is circumferentially formed at the rear end of the shaft 112. The length of the portion between the rear end of the engaging groove 113 and the front face of the flange 110 is substantially equal to the length of the central hole 107 in the holder shaft 103.

Upon assembly the adjusting shaft 109 is inserted into the central hole 107 of the holder shaft 103 from its rear.

A spring washer 114 is fitted to the portion of the adjusting shaft protruding from the fore end of the holder shaft 103. A fixing circlip washer 115 is fitted to the washer 114. In this way, the adjusting shaft 109 is rotatably but axially immovably supported by the holder shaft 103.

The axially extending cuts 108 are formed in the inner surface of the central hole 107 of the holder shaft 103.

With provision of the axially extending cuts, a contact area of the holder shaft and the adjusting shaft 109 is reduced, thereby reducing the rotation load on the adjusting shaft 109 at the time of the aiming adjustment.

In this way, the adjusting shaft 109 is supported by the holder shaft 103, thereby forming the shaft member 102.

The screw threaded part 104 of the holder shaft 103 of the shaft member 102 is screwed into the screw thread part 95 of the worm wheel 92. The guide protrusion 106 of the holder shaft 103 is slidably coupled with the guide concavity 101 of the holder 97. The pressure part 105 of the holder shaft 103 is slidably coupled with the guide cut 100 of the holder 97. In this way, the shaft member 102 is not rotated with the rotation of the worm wheel 92 but is axially movable. Further, the fore end part of the pressure part 105 protrudes out of the holder 97 through the guide cut 100.

The fore end part of the holder shaft 103 is inserted into the insertion hole 73 of the front case 69 and the tubular portion 74. The screw part 112 of the adjusting shaft 109 is screwed into a nut 38 supported by the turning end of the reflector 3.

The back case 70 includes a rear wall 116 and a side surface wall 117 extending forward from the peripheral edge of the rear wall 116. An insertion hole 118 is formed in the rear wall 116, in alignment with the insertion hole 73 of the front case 69. The rear wall 116 includes a tubular portion 119 extending forwards from the fore end opening of the insertion hole 118 and a tubular portion 120 protruding rearwards from the rear end opening of the insertion hole 118. An annular notch 121 is formed in the inner edge of the rear end of the rear tubular portion 120. A protecting wall 122 extends from the rear surface of the rear wall 116 so as to surround the tubular portion 120. The protecting wall 122 includes a plurality of circumferentially spaced cutouts 123.

A surrounding wall 124 protrudes from a portion in the vicinity of the center of the lower portion of the rear surface of the rear wall 116. When viewed from the rear side thereof, the corners thereof are curved to provide a triangle shape.

Guide walls 125 and 126, which extend downward from the edges of the right and left openings of the two cuts 123 located in the right and left lower portions of the protecting wall 122, protrude from the rear surface of the rear wall 116. The outer guide walls 125 are longer than the inner guide walls 126. The top ends 125a of the outer guide walls 125 are bent somewhat outward to reach the side edge of the rear wall 116. The inner guide walls 126 terminate before these reach the position of the surrounding wall 124. The surfaces 126a of the fore end portions thereof, which face the outer guide walls 125, are inclined gradually apart from the outer guide walls 125 toward their top ends. A guide path is formed between the guide walls 125 and 126.With provision of these paths, the top tip of an operating tool, such as a screw driver, may easily be inserted through the paths to the protecting wall 122. Since the top ends 125a of the inner guide walls 126 are slanted as described above, the tip top of the operating tool is received at this slanted top ends when it is inserted. Therefore, the insertion of the operating tool is easy. Further, the side surface of the surrounding wall 124 also extends in the same direction as that of the outer guide walls 125 and 126. Then, the surrounding wall 124 also guides the operating tool when it is inserted into the inside defined by the protecting wall 122.

Engaging pawls 127 stand upright on the outer surface of the side surface wall 117 at locations thereof corresponding to the engaging holes 91 of the front case 69. An aiming rod 128 includes a body portion 129 made of synthetic resin and a crown gear 130 made of metal. The crown gear 130 is formed at a location close to the rear end of the body portion 129 by an out-insert molding method. The crown gear is integral with the body portion 129. A gear assembly as described is applied to this aiming rod 128.

To couple integrally the main body with the gear means, any other suitable method than the out-insert molding method may be used. For example, caulking pins may protrude from the main body, holes correspondingly formed in the gear means, these pins of the main body inserted into the holes of the gear means, and the inserted portions of the pins are thermally caulked.

The portion of the body portion 129, located further fore than the crown gear 130, serves as a tubular portion 131. The tubular portion 131 is cylindrical in shape. A coupling hole 132 formed in the tubular portion 131 opens at the fore end thereof. The coupling hole 132 is oval in cross section. The slide coupling part of the adjusting shaft 109 is inserted into the coupling hole, whereby the inserted adjusting shaft is slidable but nonrotational relatively to the coupling hole.

In the tubular portion 131, slits 133 are formed at two locations facing each other in. the major axial direction in the oval cross section of the coupling hole 132. The slits 133 reach the fore end of the tubular portion. Engaging pawls 134 and 134 protrude outward from the fore end of the tubular portion 131 at the locations thereof facing each other in the minor axial direction of the oval cross section of the coupling hole 132. The front faces 134a of the engaging pawls 134 are tapered, while the rear ends 134b thereof are perpendicular to the axial direction of the tubular portion 131, thereby forming stopper faces.

The portion of the body portion 129, located further rear than the crown gear 130, is a head portion 135, hexagonal in cross section. An engaging slit 136 is formed in the rear face of the head portion 135. The engaging slit 136 extends in the direction orthogonal to the major axial direction of the oval cross section of the coupling hole 132.

The crown gear 130 made of metal is circular in shape.

The circumferential edge of the crown gear 130 is bent forward. Gear teeth 137 are formed in the forward bent portion. The tubular portion 131 of the aiming rod 128 is inserted into the insertion hole 118 of the back case 70 from its rear side. When inserted, the engaging pawls 134 and 134 of the tubular portion 131 of the aiming rod 128 are compressed to be deflected inwardly by the inner surfaces of the tubular portions 120 and 119 of the back case 70 and the insertion hole 118. After passing therethrough, the compressed engaging pawls 134 and 134 are restored to their original state. The stopper faces 134b of the engaging pawls 134 abut on the fore end of the tubular portion 119, thereby preventing the aiming rod 128 from slipping off the back case 70.The front face of a contact part 13la protruding from the rear end of the tubular portion 131 comes in contact with the rear end of the rear tubular portion 120 of the back case 70. With this arrangement, the aiming rod 128 is rotatably supported by the back case 70.

An 0 ring 138 is fitted to the base part of the tubular portion 131 of the aiming rod 128, and positioned in the ring-like cut 121 formed in the inner face of the rear end of the tubular portion 120 of the back case 70.

With this structure, water-proof is ensured.

When the front case 69 is coupled with the back case 70 in a state that the rear opening face of the front case 69 is put face to fact with the front opening face of the back case 70, the slide coupling part 111 of the adjusting shaft 109 supported by the front case 69 is coupled with the coupling hole 132 of the aiming rod 128, axially slidable but nonrotationally. Thus, the slide coupling part 111 is inserted into the coupling hole 132. As a result, the tubular portion 131 of the aiming rod 128 is prevented from being deflected to be reduced in its diameter. When the front case 69 is coupled with the back case 70 for assembling, the aiming rod 128 will never slip off the back case 70. Further, it is noted that in the aiming rod 128, the coupling hole 132 and the engaging slit 136 are oriented in a fixed relationship, as described above. With this orientation relationship, it is easy to align the slide coupling part 111 of the adjusting shaft 109 with the coupling hole 132 of the aiming rod 128 when the former is inserted into the latter.

Additionally, it is noted that in the second embodiment, unlike the first embodiment, only two slits 133 are formed in the tubular portion of the aiming rod 128.

With this feature, the rigidity of the tubular portion 131 is increased for firmly gripping the slide coupling part 111 of the adjusting shaft 109.

Reference numeral 139 designates a motor fastened to the inside of the case body 68; numeral 140 a pinion gear fastened to a rotary shaft 139a of the motor 139. A case 141 of the motor 139, oval in cross section, has two flat faces 141a and 141b oppositely located. Portions 142a and 142b protrude from both sides of the case 141 conform in shape to the large diameter portions 85a and 86a of the slits 85 and 86 of the motor receiving portions 83 and 84 formed in the front case 69. Numerals 143a and 143b designate terminal pieces projecting from one side of the flat face 141b of the case 141 of the motor 139.

In assembling, the protruding portion 142a of the case 141 of the motor 139 is put on the introducing portion 85b of the motor receiving portion 83 and the protruding portion 142a is put on the introducing portion 86b of the motor receiving portion 84. Thereafter, the motor 139 is pushed toward the front wall 71. Then, the protruding portions 142a and 142b push the slanted edges of the introducing portions 85b and 86b to open the slits 85 and 86. In turn, the protruding portions 142a and 142b are received by the large diameter portions 85a and 86a of the motor receiving portions 83 and 84, respectively. In this way, the motor 139 is supported by the front case 69. And the flat face 141a of the case 141 of the motor 139 abuts against the inner surface of the front wall 71.

A worm 144 has a shaft which is rotationally supported in parallel with the axial direction of the motor 139, and in mesh with the worm wheel 92. A spur gear 145 integral with the worm 144 is in mesh with the pinion gear 140.

Accordingly, when the motor 139 is driven, the worm wheel 92 is turned.

A coupling part 146 couples the worm 144 with the spur gear 145. A location of the coupling part 146 closer to the spur gear 145 serves as a circumferentially elongate, indented supported part 147. A thin supported shaft 148 projects from the end of the worm 144, not coupled with the spur gear 145. The supported part 147 is brought into contact with the introducing portion 81b of the worm 79 of the front case 69. The supported shaft 148 is brought into contact with the introducing portion 82b of the worm 80.

Thereafter, the worm 144 is pushed towards the front wall 71 to open the slits 81 and 82 of the worms 79 and 80. The supported part 147 and the supported shaft 148 are received by the large diameter portions 81a and 82a of the worms 79 and 80, respectively. As a result, it is rotationally supported by the front case 69. Incidentally, provision of the supported part 147 on the inner side of the spur gear 145 realizes an effective use of the space thereof.

A printed circuit board 149 includes circuitry formed thereon and mounting holes 150. Reference numeral 151 designates a connector 151 formed in front of the printed circuit board 149. Receiving holes 152a and 152b are formed in the fore end portions of the connector 151.

Terminal pieces 153 project rearwards from the rear side of the printed circuit board 149.

The caulking pins 78a of the mounting protrusions 78 formed on the front case 69 are inserted into the mounting holes 150 of the printed circuit board 149 from its front side, respectively. The portions of the caulking pins 78a projecting from the printed circuit board 149 to its rear side, after inserted, are caulked, whereby the printed circuit board 149 is supported by the front case 69. At this time, the terminal pieces 143a and 143b of the motor 139 are respectively inserted into the receiving holes 152a and 152b of the connector 151, so that the motor 139 is connected to the circuit of the printed circuit board 149.

The holder 97 and the printed circuit board 149 are caulked by the caulking pins 77a and 78a arranged in the same direction on the printed circuit board 149.

Therefore, those may be assembled automatically by an assembling machine.

In a resistor type sensor 154, a sliding member 156 is longitudinally movably supported by a case 155. A relative position of the sliding member 156 to the case 155 determines a resistance of the sensor. A spring means (not shown), provided in connection with the sliding member 156, urges the sliding member 156 forward. The end of the sliding member 156 of the resistor type sensor 154 resiliently contacts the back side of the pressure part 105 of the holder shaft 103 of the shaft member 102.

With the movement of the shaft member 102 in the longitudinal direction, the sliding member 156 of the resistor type sensor 154 moves to change a resistance of the sensor. The detected resistance may indicate a position of the shaft member 102. Further, the detected position may indicate a tilt angle of the reflector 3.

The front edge of the side surface wall 117 of the back case 70 is fit into the fitting groove 89. Before the fitting, an 0 ring 157 is fitted into the fitting groove 89. As the fore end of the side surface wall 117 is progressively fit into the fitting groove 89, the engaging pawls 127 on the outer surface of the side surface wall 117 comes into engagement with the rectangular engagement holes 91 of the outer wall 88 of the front case 69. As a result, the front case 69 is coupled with the back case 70, thereby forming the case body 68. The slide coupling part 111 of the adjusting shaft 109 is coupled with the coupling hole 132 of the aiming rod 128 .The terminal pieces 153 of the printed circuit board 149 are inserted into insertion holes 158 formed in an area of the rear wall 116 of the back case 70, which is surrounded by the surrounding wall 124, and projected to within the surrounding wall 124. In this way, a connector 159 is formed.

A plurality of slits 90 are formed in the outer wall 88 of the front case 69. Therefore, to separate the front case 69 from the back case 70, the rectangular engagement holes 91 may easily be disengaged from the engaging pawls 127 of the back case 70 by fingering outward the portion of the outer wall 88 between the slits 90 to deflect it.

If two slits are formed on both sides of each of the rectangular engagement holes 91 their disengagement is easy, but the front case 69 is easy to be broken at the slits. For this reason, the slits 90 are formed only at the corners. Thus, the initial aiming adjustment of the head lamp levelling mechanism 67 is carried out by turning the aiming rod 128.

When the aiming rod 128 is turned, the adjusting shaft 109 of which the slide coupling part 111 at the rear end thereof is slidably coupled with the coupling hole 132.

The screw shaft 112 is screwed into or out of the nut 38 depending on the turning direction. With this movement of the screw shaft, a distance between the lamp body 2 and the portion of the reflector 3 where the nut 38 is supported, is varied to tilt the reflector 3 with respect to the lamp body 2. The aiming rod 128 is turned by a screw driver, for example.

The tip 66a of a screw driver 66 with a cross is inserted to within the protecting wall 122 through one of the cutouts 123 of the protecting wall 122 of the back case 70. Then, the tip top 66a thereof reaches the gear teeth 137 of the crown gear 130 of the aiming rod 128. In this state, when the screw driver 66 is turned, its top 66a moves the gear teeth 137 of the crown gear 130 to turn the aiming rod 128.

A plurality of cutouts 123 which allow the operating tool, such as a plus driver, to pass therethrough, are circumferentially formed in the protecting wall 122.

Therefore, the access for the aiming adjustment is allowed in a plural number of directions. If the guide path defined by the outer guide walls 125 and 126 is used for the access, a smooth insertion of the operating tool is possible. The head portion 135 of the aiming rod 128 may also be used to turn the aiming rod 128. The aiming rod 128 may be turned by means of a hexagonal wrench or putting the tip top of a minus driver into the engaging slit 136, for example. The levelling adjustment is carried out through the turn of the motor 139.

When the motor 139 rotates, the worm wheel 92 turns as described above. When the worm wheel 92 turns, the screw thread part 104 is fed forward by the thread part 95, the holder shaft 103 is longitudinally moved depending on the turning direction of the worm wheel 92, and the adjusting shaft 109 supported by the holder shaft 103 is longitudinally moved. Through the longitudinal movement of the adjusting shaft 109, the distance between the lamp body 2 and the portion of the reflector 3 where the nut 38 is supported, is varied to tilt the reflector 3 with respect to the lamp body 2.

To achieve the above object, there is provided a light-beam aiming direction adjusting device for headlamps which is for tilting a tilted member so that a light-beam axis of which varies when it is tilted, comprising: a worm rotated by a motor; a worm wheel to be in mesh with the worm, the worm wheel having an axially extending hole of which the inner surface has a thread groove formed thereon, and having a flange radially extending from the outer surface thereof; a shaft member having a screw thread formed on the outer surface thereof and slide engaging means, the screw thread thereof being screwed to the worm wheel, and the shaft member being coupled with the tilted member; a holder having a contact means and engaging means, the contact means being put on the shaft member and slidably contacting the worm wheel, and the engaging means slidably engaging the slide engaging means in the axial direction; and a casing for fixing the holder, the casing having contact means slidably contacting the worm wheel, wherein the worm wheel is rotatably held between the holder and the casing, and the shaft member is axially moved with rotation of the worm wheel.

In the light-beam aiming direction adjusting device for head lamps the worm wheel is rotatably held between the casing and the holder fixed to the case member, so that the shaft member is supported by the case member in a manner that it is rotatable but axially immovable. The working for its holding is efficient, and a reliable immovability of the worm wheel in the axial direction is secured.

Claims

1. A light-beam aiming device for a headlamp for tilting a tilted member so that a light-beam axis is tilted, the device comprising a casing body; a worm rotatably supported in the casing body; means for rotating the worm; a worm wheel rotatably supported in the casing body and engaging with the worm; a shaft member having a coupling for engagement with the tilted member, the shaft member comprising a screw thread formed on an outer surface thereof, and being screwed to the worm wheel; and a holder member fixedly supported within the casing body coaxially with the shaft member, the holder member comprising a contact section slidably contacting to the worm wheel and an engaging section engaging with the shaft member so that the shaft member is slidable in an axial direction relatively to the holder member.

2. A device according to claim 1, wherein the worm wheel comprises an axially extending hole having a screw thread formed on an inner surface thereof, the screw thread engaging with the screw thread of the shaft member; and a flange radially extending from an outer surface thereof, the flange comprising a first surface slidably contacting the section of the holder and a second surface opposed to the first surface and slidably contacting the casing body.

3. A device according to claim 2, wherein the flange is integrally formed with the worm wheel.

4. A device according to any one of the preceding claims, wherein the worm wheel is made of synthetic resin and is substantially tubular in shape.

5. A device according to any one of the preceding claims, wherein the casing body is formed of a synthetic resin and comprises a front case and a back case coupled together.

6. A device according to claim 5, wherein the front case comprises a front wall; a side wall extending rearwardly from a circumferential edge of the front wall; an insertion hole formed in the front wall; a tubular portion extending forwardly from an outer opening of the insertion hole; and a support tube extending inwardly from an inner opening of the insertion hole.

7. A device according to any one of the preceding claims, wherein the holder member is formed of a synthetic resin.

8. A device according to any one of the preceding claims, wherein the worm wheel comprises a recessed part formed at a rear surface thereof and the holder member comprises a projecting part formed at a front surface thereof, and the projecting part of the holder member slidably engages with the recessed part of the worm wheel.

9. A device according to any one of the preceding claims, wherein the casing body comprises a mounting projecting member inside thereof and the holder member comprises a mounting hole receiving the mounting projecting member.

10. A device according to claim 9, wherein the mounting projecting member comprises a fastening pin.

11. A device according to any one of the preceding claims, wherein the shaft member comprises a holder shaft formed of a synthetic resin and an adjusting shaft formed of metal rotatably supported on the holder shaft.

12. A device according to claim 11, wherein the holder shaft comprises a screw thread which is screwed to the worm wheel, a guided protrusion which is slidably coupled with the holder member; and a pushing piece which is slidably coupled with the holder.

13. A device according to any one of claims 9 or 13, wherein the mounting projection is integrally formed with the casing body.

14. A device according to any one of the preceding claims, wherein the light-beam aiming direction adjusting device is coupled, in use, to a reflector of a headlamp.

15. A device according to any one of the preceding claims, wherein the light-beam aiming direction adjusting device is coupled to a headlamp body.

16. A method for assembling a light-beam aiming device, comprising steps of preparing a casing body, a shaft member, a worm wheel and a holder member; forming a subassembly by threadably engaging the worm wheel with the shaft member and thereafter engaging the holder member onto the shaft member and the worm wheel; and securing the subassembly to the casing body.

17. A method according to claim 16, wherein the casing comprises a front case and a back case, and the subassembly is secured to the front case, and then the back case is coupled to the front case.

18. A light beam aiming device for a headlamp substantially as described with reference to the accompanying drawings.

19. A method for assembling a light-beam aiming device substantially as described with reference to the accompanying drawings.