Rear view mirror assembly for motor vehicle

Abstract: A rear view mirror assembly for a motor vehicle, includes a mirror holder (1) for supporting a mirror body, an operating threaded shaft (4) provided to be capable of moving backward and forward along an approximately axis thereof in a mirror case, and a nut member (7) connected with a driving device in the case. The holder (1) is supported to be capable of inclining around a lateral and/or a vertical incline center axes with respect to the case. The head (4b) of the shaft (4) is fitted in the fitting portion (1a) of the holder (1) to be capable of inclining to the fitting portion (1a). The screwed portion of the shaft (4) is screwed in the member (7). The member (7) has an annular projecting portion (7e) for sliding on a circumfer­ ential surface of the shaft (4). The specified portion of the shaft (4), which is positioned at the opposite side to the holder (1) and away from the screwed portion, is pene­ trated through a through hole (7f) formed by the projecting portion (7e) to be capable of moving backward and forward along the approximately axis of the shaft (4) and inclining therearound. By driving of the device, the member (7) is rotated so as to backward and forward move the shaft (4) along the approximately axis thereof to the case and then to incline the holder (1) to the case.

Description: BACKGROUND OF THE INVENTION The present invention relates to a rear view mirror assembly as defined in the preamble of claim 1 and as disclosed for example in the document EP-A-0 170 296. The present invention relates to a rear view mirror assembly particularly suitable for a motor vehicle, and more particularly, an assembly of so-called outer or external reflecting mirror such as a fender mirror, door mirror, etc. for a motor vehicle in which a mirror holder of the mirror is inclined by backward and forward movement of an operating threaded shaft for angle adjustment of the mirror holder. Conventionally, there have been proposed this kind of rear view mirror assemblies for motor vehicle which have various constructions, respectively. For example, the mirror assembly is constructed as follows. A mirror holder supporting a mirror body is supported to be capable of inclining to a mirror case around a lateral and/or a vertical incline center axes with respect to the mirror case. The head of the top end of an operating threaded shaft provided so as to move backward and forward along the axial direction thereof in the case is fitted in the fitting portion of the holder to be capable of being inclined, and the middle portion of the shaft is screwed in a nut member operably connected with a driving device in the case. Then, the nut member is rotated by driving the driving device and then the shaft is moved backward and forward along the approximately axial direction thereof to the case, with the result that the holder is inclined to the case. According to the construction, however, since the head of the shaft is supported by the holder, and the middle portion of the shaft is supported by the nut member, whereby the shaft is inclined to the holder around the middle portion thereof, where the shaft is screwed in the nut member, the incline center of the shaft is positioned in the vicinity of the holder. Therefore, the incline angle of the shaft intends to increase and then the shaft moves backward and forward along the axis of the shaft while rolling around the axis thereof. As a result, it is difficult to smoothly incline the mirror body. SUMMARY OF THE INVENTION The object of the present invention is, therefore, to remedy the above-described problems and to provide a rear view mirror assembly for a motor vehicle in which a mirror body is smoothly inclined for angle adjustment of the body. In accomplishing these objects, a rear view mirror assembly according to the present invention is characterized by the features specified in the characterising portion of claim 1. According to the present invention, since the specified portion, positioned at the opposite side to the holder and away from the screwed portion where the shaft is screwed in or engaged with the nut member, of the shaft is supported by the annular projecting portion, and the shaft is inclined around the portion supported by the projecting portion and serving as a fulcrum, the incline angle of the shaft can be decreased as a whole and the inclining movement of the holder can be smoothly performed, as compared with the conventional mirror assembly in which an operating threaded shaft is supported by a portion where the shaft is screwed in a nut member. That is, in the conventional mirror assembly, the shaft is supported by a mirror holder and the portion where the shaft is screwed in the nut member, the incline center of the shaft is the portion where the shaft is screwed in the nut member, when the shaft is inclined to the holder, and the portion is located near the head of the shaft, that is, the holder. Therefore, it causes the incline angle of the shaft to intend to increase as a whole, and it is difficult to smoothly perform the inclining movement of the holder. On the other hand, in the present invention, the shaft is supported by the projecting portion, of the nut member, positioned on the opposite side to the holder, and the incline center of the shaft is the support portion where is supported by the projecting portion, that is, is positioned on the opposite side to the holder and away from the screwed portion where the shaft is screwed in the nut member, when the shaft is inclined to the holder. Therefore, the incline angle of the shaft can be decreased as a whole. BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and features of the present invention will become apparent from the following description taken in conjunction with preferred embodiments thereof with reference to the accompanying drawings, throughout which like parts are designated by like reference numerals, and in which: Figs. 1-3 show the one embodiment of the present invention, Fig. 1 is a partially enlarged cross sectional view of the rear view mirror assembly according to the embodiment; Fig. 2 is an enlarged view showing a hole inner surface configuration of a second through hole shown in Fig. 1; and Fig. 3 is a perspective view of an operating thread shaft. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Fig. 1 shows a rear view mirror assembly particularly suitable for a motor vehicle, according to the one embodiment of the present invention. In Fig. 1, a mirror holder 1 supporting a mirror body (not shown) is supported by a mirror case (not shown) to be capable of inclining around a lateral incline center axis and/or a vertical incline center axis with respect to the case respectively. A head 4b of an operating threaded shaft 4 for pushing or pulling the mirror holder 1 is fitted in a fitting portion 1a of the rear face of the holder 1 to be capable of inclining along the axial direction thereof. A screwed portion near the head 4b of the shaft 4 is screwed in or engaged with a nut member 7 operably connected with a driving device in the case. Therefore, the shaft 4 moves backward and forward along the approximately axial direction thereof by driving of the driving device through the nut member 7, so that the holder 1 is inclined to the case so as to adjust the incline angle of the mirror body. The fitting portion 1a of the rear face of the holder 1 is formed as a recess with a spherical inner surface, and the holder 1 is capable of inclining around the lateral and/or vertical incline center axes through the rotary center O thereof. As shown in Fig. 3, the shaft 4 has a small-outside diameter neck portion 4c and the ball-shaped head 4b which are integrally and axially formed at the top end of the leg portion 4a thereof in series. The head 4b is supported to be fitted therein so as to be capable of rotating by the fitting portion 1a of the holder 1. The leg portion 4a thereof has an external thread portion on the circumferential surface thereof. In the case supporting the holder 1 to be capable of inclining it, a lower casing 5 and an upper casing 8 fitting to the lower casing 5 and serving as a supporting member are provided. In both the casings 5 and 8, members such as the driving device for driving the shaft 4 are accommodated. On the lower casing 5, a through hole 5a with larger inside diameter than the outside diameter of the leg portion 4a of the shaft 4 is formed, so that the leg portion 4a of the shaft 4 is penetrated through the hole 5a to be capable of moving approximately axially and relatively inclining. The driving device is provided with a driving motor (not shown) and the nut member 7 operably connected with the driving motor and fitted on the outer surface of the shaft 4. The nut member 7 has a projecting wall 7a circumferentially formed projecting from the upper casing 8, and the wall 7a thereof is rotatably fitted inside a supporting wall 8c of the upper casing 8 to be positioned. The upper surface of the nut member 7 is relatively rotatably fitted in a recess 5b positioned on the upper casing side of the lower casing 5. Then, the nut member 7 is rotated guiding between the casings 5 and 8. A spring arm 7d is fitted on the middle inner surface of an axial first through hole 7c of the middle of the nut member 7, so that the arm 7d is capable of rotating together with the nut member 7. The arm 7d is engaged with the external thread portion on the outer circumferential surface of the leg portion 4a of the shaft 4 to prevent the shaft 4 from freely moving in the axial direction of the shaft 4 to the nut member 7. Therefore, when the nut member 7 rotates normally and reversibly between the casings 5 and 8, since the nut member 7 can not move in the axial direction of the shaft 4 to the case, the shaft 4 engaged with the arm 7d moves backward and forward in the approximately axial direction thereof. The first through hole 7c has such a larger inside diameter than the outside diameter of the shaft 4 that the shaft 4 is capable of inclining thereto, and such figuration that the arm 7d fitted in the nut member 7 can be biased in the first through hole 7c. On the other hand, an annular projecting portion 7e sliding on the outer circumferential surface of the shaft 4 is formed on the opposite side, to the mirror holder, of the first through hole 7c of the nut member 7. By the projecting portion 7e, a second through hole 7f is formed. Therefore, the leg portion 4a of the shaft 4 is penetrated through the second through hole 7f to be capable of inclining and approximately axially moving. Then, the second through hole 7f has the approximately same inside diameter as the outside diameter of the leg portion 4a of the shaft 4, and such an approximately arc cross-sectional inner surface 7′e, serving as an inner surface of the projecting portion 7e, that the shaft 4 is capable of inclining to the second through hole 7f as shown in Fig. 2. In Fig. 1, reference numeral 2 denotes a rubber simplified water-proof sealing member for preventing water from inserting in the casings 5 and 8 through the shaft 4. According to the construction of the embodiment, the mirror assembly in which the holder 1 is assembled into the case is operated as follows. When the driving motor is driven, the nut member 7 is rotated so as to backward and forward move the leg portion 4a of the shaft 4 in the approximately axial direction thereof. At that time, when the holder 1 is pushed by the shaft 4, the head 4b of the shaft 4 pushes the fitting portion 1a of the holder 1 so as to incline the holder 1 to the case around the lateral incline center axis and/or the vertical incline center axis. When the holder 1 is pulled by the shaft 4, the head 4b of the shaft 4 pulls the fitting portion 1a of the holder 1 toward the casings 5 and 8 so as to incline the holder 1 to the case around the lateral incline center axis and/or the vertical incline center axis. Since the shaft 4 is assembled into the case to be capable of inclining and approximately axially moving, the head 4b of the shaft 4 is inclined to the holder 1 as well as the casings 5 and 8 in the fitting portion 1a thereof in inclining the holder 1. The inclining movement of the shaft 4 is regulated by the second through hole 7f formed by the annular projecting portion 7e of the nut member 7. That is, the shaft 4 is inclined around the support portion supported by the projecting portion 7e and serving as a fulcrum in the second through hole 7f. A support portion, positioned on the opposite side to the holder 1, of the shaft 4 is hardly displaced in the direction perpendicularly intersecting to the axial direction of the shaft 4 on the basis of the incline of the shaft 4. Here, the end, positioned on the opposite side to the holder 1, of the shaft 4 has a sufficient axial length not to fall from the second through hole 7f. Some of the incline of the shaft 4 in the first through hole 7c of the nut member 7 can be absorbed by bias movement of the arm 7d. According to the embodiment, the support portion of the shaft 4 which is positioned away from the screwed portion screwed in the nut member 7 of the shaft 4 and on the opposite side to the holder 1, is supported by the annular projecting portion 7e formed the second through hole 7f of the nut member 7, and the shaft 4 is inclined around the support portion of the shaft 4, which is supported by the portion 7e and served as a fulcrum. Therefore, the incline angle of the shaft 4 can be decreased as a whole, resulting in smooth inclining movement of the mirror body, as compared with the conventional mirror assembly in which an operating threaded shaft is supported by a portion screwed in a nut member. That is, in the conventional mirror assembly, the shaft is supported by the nut member and a mirror holder, and when the shaft is inclined to the holder, the incline center of the shaft is the support portion supported by the nut member. Therefore, the incline angle of the shaft intends to be increased as a whole, resulting in prevention from smoothly performing the inclining movement of the mirror body. As compared with this assembly, in the embodiment, the shaft 4 is supported by the nut member 7, the holder 1, and the upper casing 8, and when the shaft 4 is inclined to the holder 1, the incline center thereof is the support portion supported by the projecting portion 7e of the nut member 7, that is, the support portion where is positioned away from the screwed portion screwed in the nut member 7 and on the opposite side to the holder 1. Therefore, the incline angle thereof can be decreased as a whole. Furthermore, in the embodiment, it is possible that the support portion of the shaft 4 where is positioned on the opposite side to the holder 1, is supported by the upper casing 8, and the incline center of the shaft 4 is dislocated to the support portion supported by the upper casing 8 so as to decrease the incline angle of the shaft 4. In such a mirror assembly, however, it is required for the shaft 4 to sufficiently elongate the shaft length to the upper casing 8 for supporting the shaft 4, resulting in elongation of the shaft 4. On the other hand, since in the embodiment, the shaft 4 is supported by the projecting portion 7e of the nut member 7, it can prevent from causing such a disadvantage.

Claims: A rear view mirror assembly comprising: a mirror holder (1) supporting a mirror body and supported by a mirror case, the mirror holder (1) being inclinable around one of a lateral and a vertical incline center axes with respect to the case; an operating threaded shaft (4) provided movable backward and forward along an approximate axis thereof in the case, a head (4b) of said shaft (4) being fitted in a fitting portion (1a) of said holder (1) to be inclinable relative to the fitting portion (1a); and a nut member (7) operably connected with a driving device in the case, and wherein by driving the device, said member (7) is rotated to move the shaft (4) backward and forward along the approximate axis thereof to the case and then to incline said holder (1) relative to the case and wherein said member (7) has a spring arm (7d) engaged with a screwed intermediate portion of said shaft (4) so that said shaft (4) is screwed in said member (7), characterized in that said member (7) having an annular projecting portion (7e) for sliding on and guiding a cylindrical surface of said shaft (4) which is formed at the end of the opposite side to said holder (1), said annular projecting portion (7e) contacting a relatively small portion of the shaft (4) so that being a fulcrum for the shaft, said member (7) being penetrated from the shaft through a through hole (7f) formed by the projecting portion (7e) thereof to be movable backward and forward along the approximate axis of said shaft (4) and inclinable therearound. The rear view mirror assembly (for a motor vehicle) as claimed in claim 1, wherein the inner surface (7e') of the through hole (7f) has an arc cross-sectional configuration to facilitate inclining of the shaft (4). The rear view mirror assembly as claimed in claim 1, wherein the head (4b) of said shaft (4) is formed as a ball portion, and the fitting portion (1a) of said holder (1) has a spherical inner surface for supporting the ball-shaped head of said shaft (4) to he inclinable relative to the fitting portion thereof.

Inventors: OGASAWARA MORIHIKO C O KABUSHI, OGASAWARA, MORIHIKO C/O KABUSHIKI KAISHA
Applicants: TOKAI RIKA CO LTD, KABUSHIKI KAISHA TOKAI RIKA DENKI SEISAKUSHO
Application year: 1989
Main classification: B60R1
IPC codes: B60R1