Stay housable type motor driven mirror

Abstract: A stay housable type motor driven mirror to be attached, for example, to a car body has a drive gear (33) rotatably driven by a drive apparatus (31), a clutch gear (37a) adapted to fit idlingly onto the support shaft (36) and engage with the drive gear (33), a clutch holder (37b) fitted onto the support shaft beneath the clutch gear in order to rotate the support shaft (36) by its rotation, a clutch mechanism (37c) having a concave face and a convex face, each so formed on lower face of the clutch gear (37a) and an upper face of the clutch holder (37b) as to engage with each other, and a spring (41) pressing the clutch gear to make the concave face and the convex face of the clutch mechanism (37c) engaged with each other. Consequently, it is possible to install the clutch mechanism at a side of follower of a large diameter gear and to increase a design allowance of clutch holding torque. In addition, a height (H) of a bracket case (4) is made shorter. Increasing an interior space of the bracket case (4) increases design allowance of size and arrangement of the constitutional parts of the mirror simplifying the attachment.

Description: The present invention relates of a stay housable type motor driven mirror comprising a stay, a mirror body supported at a top end of said stay, a support shaft rotatably held in a bracket case, said stay having a foundation which is attached to the support shaft, a drive apparatus for driving said support shaft, a transmission mechanism including a first gear attached to this drive apparatus and a second gear engaged with said first gear for driving said support shaft; a clutch mechanism, comprising a concave face and a convex face, said clutch mechanism being operated by a spring; and an engagement means including a spring-operated ball urged against the base portion of said bracket case. Such a motor driven mirror is known from EP-A1-0 314 135. According to EP-A1-0 314 135 there is provided a first spring for operating the clutch mechanism while a plurality of second springs are necessary for urging on said balls which results in a bulky structure. If the stay is rather long and the bracket case attached to a vehicle body shakes a little, the top end of the stay and the mirror will shake largely because a small degree of shake of the bracket case attached to the vibrating vehicle body is magnified many times at the top end of the long stay, resulting in considerable shake of the mirror device. In particular, ordinarily a radial-directed load is effected to the foundation of the stay when the drive motor transfer its power to the mirror device, and additionally windage or Wind-breaking resistance attacks the mirror body at the top end of the stay, thereby play is apt to generate between the bracket case and the stay. In addition, if the drive motor directly drives or rotates the stay this will result in a disadvangageously large drive mechanism. According to JP-U1-3-22041 of the applicant a stay of the stay housable type motor driven mirror can be supported a stable condition without any generation of play and additionally a drive mechanism of the mirror can minituarize which will be described in connection with figures 6 to 9 showing said known device. In Fig. 6 a mirror body 2 supporting a mirror glass is attached to a top end of the stay 1 curved about in a shape of crank. A foundation of the stay 1 is assembled into a bracket case 4 attached to a vehicle body 3. The stay 1 is driven by a drive mechanism 5 installed in the bracket case 4. The drive mechanism 5 is adapted to transfer power of a drive motor 6 to the support shaft 11 supporting the stay 1 through speed reduction mechanism 7, clutch mechanism 8, drive gear 9, and follower gear 10 so as to rotate the shaft 11. As shown in FIG 10, the support shaft 11 has a reducing lower end 12a and an enlarged upper end or flanged portion 12. The lower end 12a is engaged with the follower gear 10 with a play along a predetermined direction. Rotational force of the follower gear 10 can be transferred to the support shaft 11 after the rotation passes such play zone. There is a first engagement means 15 between facing faces of the upper flanged portion 12 and an upper lid 14 of the bracket case 13. There is a second engagement means 17 between the follower gear 10 and a lower lid 16 of the bracket case 13. The first engagement means 15 consists of a groove 18 formed on a rear side of the flanged portion 12 of the support shaft 11 and a convex portion 18 formed on the upper lid 14 of the bracket case 13. These groove 18 and the convex portion 18 are engaged with each other. The second engagement means 17 consists of a slanted concave portion 20 of the follower gear 10, an hole 22 formed on the lower lid 16 of the bracket case 13, and a ball 21 placed in the concave portion 20 and the hole 22. The sectional shape of the slanted concave portion 20 is similar to a saucer and the ball 21 can ride or climb along the slanted side wall of the saucer. When the drive motor 6 of the drive mechanism 5 drives the drive gear 9 and rotation of the drive gear 9 is transferred to the follower gear 10, first the support shaft 11 moves upward until the follower gear 10 contacts with the reducing lower end portion 12a of the support shaft 11 so as to release an engagement condition of the ball 21 of the second engagement means 17 and the concave portion 20 of the follower gear 10, simultaneously release another engagement condition of the convex portion 19 of the first engagement means 15 and the groove 19. It is noted that the first engagement means 15 is a combination of the groove 18 and the convex portion 19, and second engagement means 17 is a combination of the slanted concave portion 20, the ball 21 and hole 22. Always urging and resilient force of a coil spring 23 makes them combined in order to prevent the support shaft 11, or the stay 1 from rotating. Consequently, when driving of the drive mechanism 5 rotates the follower gear 10, the ball 21 climbs the slanted side wall of the slanted convex portion 20 and engagement condition of the second engagement means 17 is released against resilient force of the spring 23. Simultaneously, the support shaft 11 is pushed up and engagement condition of the first engagement means 15 is released or disengaged, the follower gear 10 rotates the support shaft 11 after rotation of the gear 10 passes the play zone, and the stay 1 rotates moving the mirror body 2. The clutch mechanism 8 placed at a drive side of the stay housable type motor driven mirror has a pair of convex portion 26 and concave portion 25, respectively formed on an upper face of the drive gear 9 and a lower face of the pressing plate 24. During a driving period of the motor driven mirror, the convex portion 26 and concave portion 25 are engaged with each other, so force of the drive motor 6 and the speed reduction gear mechanism 7 is transferred from the pressing plate 24 to the drive gear 9, rotating the follower gear 10 as described above. When the mirror body 2 is given some force from the outside, the stay 1 has large load or stress, and rotation force is transferred reversely from the follower gear 10 to the drive gear 9, an engagement of the clutch mechanism 8 is disengaged resisting a force of the spring 27, no load is applied to the speed reduction gear mechanism 7, and the drive motor 6 is prevented from injuring itself such as burning and the like. As described above, in the conventional stay housable type driven mirror the engagement means 15 and 17 adapted to be effective by spring force support the support shaft 11 without play. However, when the mirror body 2 of the conventional stay housable type motor driven mirror takes outside force and the support shaft 11 is compulsorily made to rotate, a load of the outside force is transferred to the drive gear 9 since the clutch mechanism 8 having a shock absorbing function is installed on the drive gear 9. Consequently, a design allowance of clutch holding torque is made small and a suitable shock absorbing effect is not attained. Since the clutch engaging spring 27 is installed at the driving side of the motor driven mirror, the height of the drive mechanism including the clutch mechanism disadvantageously increases resulting in a large size of whole construction of the device. According to the present invention there is provided a stay housable type motor driven mirror of the type as described at the beginning wherein said clutch mechanism comprises a clutch gear placed at the side of said support shaft so as to idlingly rotate and engage with the drive gear and a clutch holder fitted on the support shaft and on the clutch gear so as to rotate the support shaft by its rotation, said clutch mechanism being formed on a lower face of the clutch gear and an upper face of the clutch holder which should engage with each other, said spring pressing the clutch gear making said concave face engage with convex face of the clutch holder and said ball being arranged on the lower face of the clutch holder opposite to said base portion. Moreover, there is provided a similar stay housable type motor driven mirror wherein said clutch mechanism comprises a clutch gear placed at the side of said support shaft so as to idlingly rotate and engage with the drive gear and a clutch holder fitted on the support shaft so as to rotate the support shaft by its rotation, said clutch gear being fitted on a base portion of said clutch holder; said clutch mechanism being formed on a lower face of the clutch gear and an upper face of the clutch holder which should engage with each other, said first spring pressing the clutch gear making said concave face engage with convex face of the clutch holder while a second spring is provided for pressing said clutch holder, and said ball being arranged on the lower face of the clutch holder opposite to said base portion. The present invention provides a stay housable type motor driven mirror having a sufficient design flexibility given to a holding torque of the clutch due to an installation of the clutch mechanism formed at a side of the follower portion. Moreover, the bracket case can be miniatuarised which , compared to known mirrors of this type increases the design flexibility for fixing a motor driven mirror on a vehicle. When the mirror body is given an outside force and the stay is compulsorily rotated, the clutch mechanism disengages against a spring force. Thus the support shaft and the clutch holder slip on the clutch gear preventing the gears of the drive mechanism from being broken. According to a preferred embodiment of the invention the drive portion of the drive apparatus is transversely arranged decreasing a height of the bracket case, thus further increasing the design flexibility of mirror attachment to the car body, and the design allowance of sizes and arrangement layout of the constitutional parts or members. Brief Description of the Drawings FIG 1 is a longitudinal section of the interior construction of the stay housable or storageable type motor driven mirror according to a first embodiment of the present invention. FIG 2 is a section taken along line A-A of FIG 1. FIG 3 is a sectional view of a second embodiment according to the invention. FIG 4 is a sectional view of a third embodiment according to the invention. FIG 5 is a plan view of the interior construction of the stay housable type motor driven mirror of the third embodiment of the present invention. FIG 6 is a side view of a known stay housable type motor driven mirror. FIG 7 is a longitudinal section showing an interior construction of the known stay housable type motor driven mirror. FIG 8 is an exploded perspective view of the conventional stay housable type motor driven mirror shown in FIG 8. FIG 9(1) shows a section of cuntion of the support shaft and the follower gear before their rotation and FIG 9 (2) is a section after they rotate. Preferred Embodiment The stay housable type motor driven mirror of the present invention will be explained with reference to FIG 1, FIG 2. A mirror body supporting a mirror glass is attached to a top end of the stay 1. The foundation of the stay 1 is assembled in the bracket case 4 installed on the car body 3 and driven by a drive mechanism 5 placed within the bracket case 4. The drive mechanism 5 of the stay housable type motor driven mirror according to the present invention has a drive motor 31, a speed reduction mechanism 32, and a drive gear 33 mounted on an output shaft 32a of the speed reduction mechanism 32. At a lower end portion of the support shaft 36 supporting the stay 1 and rotatably held in the bracket case 4, a follower gear 37 is fitted. The follower gear 37 consists of a clutch gear 37a idle-rotatably fitted to the support shaft 36 and engaged with the drive gear 33, and a clutch holder 37b engaged with the clutch gear 37a through a clutch mechanism 37c. As shown in FIG 2 the clutch holder 37b is fitted to the dia-reduced portion 38 at a lower end of the support shaft 36 with a play movement along a predetermined direction. It is noted that the clutch mechanism 37c has a V-shaped protrusion 39b and a V-shaped groove 39a, respectively formed on the lower face of the clutch gear 37a and on the upper face of the clutch holder 37b. The clutch mechanism 37c functions when these V-shaped protrusion 39b and V-shaped groove 39a are engaged with each other. The clutch mechanism 37c is always urged to engage by means of a coil spring 41 placed between the clutch gear 37a and a spring holder 40 attached to an inner face of the bracket case 4. An engagement means 43 placed on the lower face of the clutch holder 37b consists of a slanted concave portion 43a formed in a base member 4b secured in a lid member 4a placed at a lower interior of the bracket case 4, a ball 42, and a concave portion 43b as shown in FIG 2. The coil spring 41 urges the engagement means 43 and also the clutch mechanism 37c. When the drive gear 33 is rotatably driven by the drive motor 31 and the speed reducing mechanism 32, the follower gear 37 comprising the clutch mechanism 37c, clutch gear 37a, and clutch holder 37b rotates as a unit, a rotation of the follower gear 37 is transferred to the support shaft 36 to revolve the stay 1 and to move the mirror body 2. When the mirror body 2 is given outside force and the support shaft 36 is forcibly rotated, the clutch mechanism 37c is disengaged against a force of the coil spring 41 and the clutch holder 37b idlingly rotates on the clutch gear 37a preventing the outside force from being transferred to the drive mechanism. As apparent from the description above, the stay housable type motor driven mirror according to the present invention comprises the drive gear 33 rotatably driven by the drive mechanism 5, a clutch gear 37a rotatably fitted to the support shaft 36 and engaged with the drive gear 33, a clutch holder 37b fitted to the support shaft 36 beneath the clutch gear 37a so as to rotate the support shaft 36 when it rotates, a clutch mechanism 37c comprising the convex face and concave face, respectively formed on the lower face of the clutch gear 37a and on the upper face of the clutch holder 37b so as to engage with to each other, and a spring 41 for pressing the clutch gear 37a so as to make the convex and the concave faces of the clutch mechanism 37c engaged, wherein the clutch mechanism 37c for giving shock absorbing function when the mirror body 2 is given an outside force is provided at a side of the follower, thereby it is possible to give a design allowance to the clutch holding torque surely making the shock absorbing function effective. In addition, no spring for the clutch at a side of driving is necessary resulting in a possibility of decrease of the height of the drive portion (H size in FIG 1), of miniaruarization the whole size of the motor driven mirror, and of decrease of the number of parts of the motor driven mirror of the present invention. FIG 3 depicts a second embodiment of the stay housable type motor driven mirror. Respective corresponding parts or members of the second embodiment shown in FIG 3 have the same reference numerals as that of FIG 1. According to the second embodiment of the present invention, a drive mechanism or apparatus 5 has a drive motor 31, a speed reducing gear mechanism 32, a drive gear 33 provided on an output shaft 32a of the speed reducing gear mechanism 32. A follower gear 37 is fitted to a lower end portion of the support shaft 36 rotatably held in the bracket case 4 so as to hold a stay 1. The follower gear 37 comprises a clutch holder 37b fitted to a lower end portion of the support shaft 36 so as to rotate the support shaft 36, and a clutch gear 37a engaged with the drive gear 33 and with the flanged portion 37d of the clutch holder 37b through a clutch mechanism 37c. The clutch holder 37b is fitted to the dia-reduced portion 38 formed on the lower end of the support shaft 36 with a play along a predetermined rotational direction in a manner as known from the conventional stay housable type motor driven mirror. The clutch mechanism 37c has a pair of V-shaped grooves 39a and V-shaped protrusions 39b, respectively formed on an upper face of the flanged portion 37d of the clutch holder 37b and on a lower face of the clutch gear 37a. When these V-shaped groove 39a and V-shaped protrusion 39b are engaged with each other, a clutching function of the clutch mechanism 37c is done. The clutch mechanism 37c is always urged toward a direction of its engagement by means of a first coil spring 41a interposed between the upper face of the clutch gear 37a and a spring pressor 40 attached to an inner face of the bracket case 4. An engagement means 43 is provided on the lower face of the clutch holder 37b. The construction of the engagement means 43 is the same as that of the engagement means shown in FIG 2 and it has a combination of the slanted concave portion 43a, ball 42, and concave portion 43b. The engagement means 43 is always urged along its engagement direction by a second coil spring 41b inserted between an upper face of a boss portion 37e of the clutch holder 37b and the spring pressor 40. In short, the stay housable type motor driven mirror of the present invention has a set of coil springs 41a and 41b, so that no influence of the spring effective to the engagement means 43 is applied to the clutch mechanism 37c. An operation of the stay housable type motor driven mirror will be explained. When the drive gear 33 is rotatably driven by a drive mechanism comprising the drive motor 31 and the speed reduction mechanism 32, the clutch mechanism 37c of the clutch holder 37b and clutch gear 37a is kept engaged with each other and rotates as a unit of the follower gear 37, a rotation is transferred to the support shaft 36 rotating the stay 1 and moving the mirror body fixed to the stay 1. In the second embodiment the clutch holder 37b is fitted to the lower end portion of the support shaft 36 so as to rotate the support shaft 36 through its rotation, the clutch gear 37a is fitted to the boss portion 37e of the clutch holder 37b in a manner of idling rotation and engaged with the drive gear 33. The first spring 41a urges on the clutch gear 37a so as to make the concave and the convex faces of the clutch mechanism 37c engaged, and the second spring 41b acts on the clutch holder 37b. Consequently, urging force of the springs is divided in order to decrease a spring load given to the clutch mechanism 37c giving a shock absorbing effect to the stay 1 when outside force is given to the mirror body, wear of the clutching members decreases, and life-time and durability of the motor driven mirror improves. Since the clutch mechanism 37c is placed at a side of said follower gear 37 and two springs are installed in the motor driven mirror of the present invention, it is possible to give a design allowance to a clutch holding torque and make the shock absorbing effect sure or reliable. Also, clutching spring to be installed at a side of driving is made unnecessary, and length of the springs to be employed to the motor driven mirror can be shortened by employing to springs, resulting in short height (H size in FIG 3) of the drive portion and minituarization of the whole construction of the mirror. The third embodiment of the stay housable type motor driven mirror of the present invention will be described with reference to FIG 4 and FIG 5. The drive portion 50 of the drive apparatus 5 of the third embodiment has an output shaft 54 for outputting a power of the drive motor 52 through the speed reduction gear mechanism 53, and a drive bevel gear 55 fitted onto the output shaft 54. A follower gear mechanism 37 of a follower portion 56 of the drive apparatus 5 consists of a clutch holder 37b fitted onto a diameter reduced portion 38 placed on the lower portion of a support shaft 36 supporting a stay 1, and a clutch gear 37a fitted onto the clutch holder 37b and engaged with the clutch holder 37b through a clutch mechanism 37c. A lowest portion of the support shaft 36 is journalled in a journal hole 4c of a base member 4b in a lid body 4a placed under the bracket case 4. An engagement means 43 is placed between the base member 4b and the clutch holder 37b. The clutch mechanism 37c in the third embodiment is identical with the one described in conjunction with Fig. 2. Between or at mid position of the follower portion 56 and the drive portion 50 of the drive apparatus 5, there is a mid bevel gear mechanism 63. The mid bevel gear mechanism 63 comprises a bevel gear portion 64a engaged with a drive bevel gear 55 of the drive portion 50, a mid bevel gear 65 provided with a spur gear portion 64b engaged with the clutch gear 37a of the follower portion 56, and a mid shaft 66 on which the mid bevel gear 65 is loosely fitted. Both of upper end and lower end of the mid shaft 66 are journalled to the bracket case 4 and the lid body 4a. The mid shaft 66 has a bearing portion 67 formed therein to journal or support a front end portion 54a of the output shaft 54 of the drive portion 50. The front end portion 54a of the output shaft 54 is inserted into the bearing portion 67 through a bushing 68. An E ring 69 supporting the mid bevel gear 65 is attached to the mid shaft 66. Operation of the third embodiment of the stay housable type motor driven mirror of the present invention will be explained. When the drive motor 52 of the drive portion 50 of the drive apparatus 5 is driven, an output of the motor 52 is transferred to the output shaft 54 through the speed reduction gear mechanism 53, so the drive bevel gear 55 is rotatably driven. Further, the output is transferred to the mid bevel gear 65 of the mid shaft 66 and the clutch gear 62 of the follower portion 56 is rotatably driven through the spur gear portion 64b of the mid bevel gear 65. As a result, the clutch mechanism 37c rotates the support shaft 36 and stay 1 through the engaged clutch holder 60 and the mirror body moves. Then, the ball 42 of the engagement means 43 is disengaged from the slanted groove portion 43a. In case that an outside-force is given to the mirror body so as to forcibly rotate the stay 1 and the support shaft 36, the clutch mechanism 37c is disengaged and the clutch holder 37b slips on the clutch gear 37a preventing the outside force from being transferred to the drive portion 50. In the third embodiment the drive portion 50 of the drive apparatus 5 is arranged transversely. As a result the height h of the bracket case 4 decreases and thus the design freedom or flexibility in attachement of the motor driven mirror to the car body is enhanced. Further, an interior space of the bracket case 4 increases giving design allowance to the size and arrangement and the like of the constitutional parts of the mirror and simplifying a method and construction of the attachment above. Although the stay housable type motor driven mirror of the present invention has been explained with reference to its preferred forms, it is to be understood to the person pertaining to the field that other forms might be adopted and all variations come within the meaning of the claims.

Claims: A stay housable type motor drive mirror comprising: a stay (1), a mirror body (2) supported at a top end of said stay, a support shaft (36) rotatably held in a bracket case (4), said stay (1) having a foundation which is attached to the support shaft (36), a drive apparatus (5) for driving said support shaft (36), a transmission mechanism including a first gear (33) attached to this drive apparatus (5) and a second gear (37a) engaged with said first gear (33) for driving said support shaft (36); a clutch mechanism (37c), comprising a concave face and a convex face, said clutch mechanism being operated by a spring (41); and an engagement means (43) including a spring-operated ball (42) urged against the base portion (46) of said bracket case (4), characterised in that said clutch mechanism comprises a clutch gear (37a) placed at the side of said support shaft (36) so as to idlingly rotate and engage with the drive gear (33) and a clutch holder (37b) fitted on the support shaft (36) and on the clutch gear (37a) so as to rotate the support shaft by its rotation, said clutch mechanism (37c) being formed on a lower face of the clutch gear and an upper face of the clutch holder which should engage with each other, said spring (41) pressing the clutch gear (37a) making said concave face engage with convex face of the clutch holder and said ball (42) being arranged on the lower face of the clutch holder opposite to said base portion (4b). Stay housable type motor driven mirror according to claim 1, characterised in that there is provided one spring (41) bearing on said clutch gear (37a) for operating said clutch mechanism (37c) and for urging said engagement means (43). A stay housable type motor driven mirror comprising: a stay (1), a mirror body (2) supported at a top end of said stay, a support shaft (36) rotatably held in a bracket case (4), said stay (1) having a foundation which is attached to the support shaft (36), a drive apparatus (5) for driving said support shaft (36), a transmission mechanism including a first gear (33) attached to this drive apparatus (5) and a second gear (37a) engaged with said first gear (33) for driving said support shaft (36); a clutch mechanism (37c), comprising a concave face and a convex face, said clutch mechanism being operated by a first spring (41a); and an engagement means (43) including a spring-operated ball (42) urged against the base portion (4b) of said bracket case (4), characterised in that said clutch mechanism comprises a clutch gear (37a) placed at the side of said support shaft (36) so as to idlingly rotate and engage with the drive gear (33) and a clutch holder (37b) fitted on the support shaft (36) so as to rotate the support shaft by its rotation, said clutch gear (37a) being fitted on a base portion of said clutch holder (37b); said clutch mechanism (37c) being formed on a lower face of the clutch gear and an upper face of the clutch holder which should engage with each other, said first spring (41a) pressing the clutch gear (37a) making said concave face engage with convex face of the clutch holder while a second spring (41b) is provided for pressing said clutch holder (37b), and said ball (42) being arranged on the lower face of the clutch holder opposite to said base portion (4b). The stay housable type motor driven mirror according to one of claims 1 to 3, characterised in that a drive portion (50) of the drive apparatus (5) is arranged transversely, a drive bevel gear (55) is fitted onto an output shaft (54) of the drive portion (50), and a mid bevel gear mechanism (63) simultaneously engaging with the drive bevel gear (55) and the clutch gear (37a) of a follower portion (56) is placed in a mid space of the drive portion of the drive apparatus (5) and the follower portion (56). The stay housable type motor driven mirror according to claim 4, characterised in that a mid shaft (66) on which a mid bevel gear (65) is loosely fitted is placed in the bracket case (4), and said mid shaft (66) has a bearing portion supporting said output shaft (54) of the drive portion (50).

Inventors: ENOMOTO MASAO, YAMAMOTO MASAMI, YAMAUCHI YOSHINORI, ENOMOTO, MASAO, YAMAMOTO, MASAMI, YAMAUCHI, YOSHINORI
Applicants: ICHIKO INDUSTRIES LTD, ICHIKOH INDUSTRIES LIMITED
Application year: 1991
Main classification: B60R1
IPC codes: B60R1