JPH08310303A - Over-load preventing mechanism for remote control mirror - Google Patents

Abstract

PURPOSE: To strengthen a U-shaped spring to increase drag of an advancing and retracting rod against advance and retract by external force, and eliminate the need to increase the capacity of a drive motor and the strength of a transmission gear train. CONSTITUTION: A male screw rod 8a of an advancing and retracting rod 8 is inserted into the center hole 13b of a spring holder 13, and pinched in a U-shaped spring 5. The spring holder 13 is connected to a clutch driven plate 17 through a spring holder guide 21. A clutch drive plate 16 is mounted to the cylindrical boss 10a of a worm wheel 10, and pressed against the clutch driven plate 17 by a clutch spring 15. When transmission torque is abnormally increased, the clutch plates 16, 17 are slipped off before the U-shaped spring 5 gets over the screw threads of the male screw rod 8a, and thus to prevent over-load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a remote control mirror device for tilting a mirror holder which is tiltably supported by a drive motor so that tilting of the mirror holder is prevented by an external force or forced by an external force. The present invention relates to a mechanism for preventing the drive motor and its transmission system from being overloaded in the event of being damaged.

[0002]

2. Description of the Related Art FIG. 6 is a sectional view showing a conventional example of a remote control mirror. Reference numeral 1 denotes a housing of the drive unit, which is composed of a housing body 1a and a housing lid 1b. The drive unit housing 1
A drive motor (not shown) and a transmission system member including a reduction gear train are housed inside. Reference numeral 2 in the drawing denotes a driven gear at the final stage of the reduction gear train. The driven gear 2
An advancing / retreating rod 3 having a screw rod 3a is inserted into a center hole 2a of the ball, and one end of the advancing / retreating rod 3 has a joint ball 3b for a ball joint.
Are connected continuously. On the other hand, a mirror holder 4 to which a mirror (not shown) is fixed is supported so as to be tiltable with respect to the housing lid 1b, and the joint ball 3b of the advancing and retracting rod 3 is attached to the concave spherical seat 4a formed on the mirror holder. It is rotatably fitted. A U-shaped spring 5 (a cross section is shown in FIG. 6) mounted on the driven gear 2 sandwiches the male screw rod 3a of the advancing / retreating rod 3. 1c is a rubber waterproof cover. The driven gear 2
FIG. 7 shows a perspective view in which the U-shaped spring 5 and the advancing / retreating rod 3 are extracted and drawn. The driven gear 2 is provided with a spring insertion hole 2b orthogonal to the central hole 2a, and a U-shaped spring 5 is inserted and held in the spring insertion hole 2b. The male screw rod 3a of the advancing / retreating rod 3 is inserted into the central hole 2a in the direction of the arrow a while bending the legs of the U-shaped spring 5 so as to spread them, and the pushed U-shaped spring has an elastic restoring force. The male screw rod 3a is sandwiched by. (Refer to FIG. 6) When the driven gear 2 is rotated, the U-shaped spring 5 attached to it is also rotated. On the other hand, the advancing / retreating rod 3 is prevented from rotating around the axial center so as to be slidable in the axial direction (in the conventional example, the male screw rod 3 is provided).
It cannot rotate because the joint ball 3b is eccentric with respect to a). The U-shaped spring 5 acts as a nut because the screw troughs of the male screw rod 3a are sandwiched by both legs, and the advancing / retreating rod 3 is screw-fed in the vertical direction in the figure as the U-shaped spring 5 rotates. The mirror holder 4 is tilted.

In this conventional example, the reason why the center hole of the driven gear 2 is not a female screw hole, but the male screw rod 3a is elastically sandwiched by the U-shaped spring 5 which is an elastic member is as follows.
(B) When the mirror holder 4 reaches the tilt stroke end, or when the mirror holder 4 is prevented from tilting by an external obstacle, when the drive motor (not shown) rotates the driven gear 2, the U-shaped spring 5 Since both legs of the motor drive over the threads of the male threaded rod 3a and run idle, there is no risk of the drive motor being locked and burned by the overload current. In this way, the function as a clutch for cutting off the transmission of excessive rotational torque can be achieved, and (b) the mirror holder 4
When a collision occurs with an external obstacle and an excessive external force in the thrust direction acts on the advancing / retreating rod 3, the advancing / retreating rod 3 moves in the thrust direction while causing the U-shaped spring to pass over the thread, and absorbs the impact. This is because the buffer function is fulfilled in this way.

[0004]

The conventional techniques shown in FIGS. 6 and 7 have the following two problems.

(1) When an automobile equipped with a remote control mirror travels at a high speed, a large wind pressure is applied to the mirror holder 4, and the advancing / retreating rod 3 receives a thrust force due to the wind pressure. The U-shaped spring 5 needs to be a strong spring (having a large spring constant) that does not get over the screw thread of the male screw rod even if it receives a thrust force caused by wind pressure. However, when the mirror holder 4 is prevented from tilting due to an external cause, the U-shaped spring 5 also functions as a clutch that prevents the overload due to idling due to screw thread over. Therefore, if the U-shaped spring 5 is strengthened so as to withstand a high wind pressure, the drive motor may be overheated by an overload current unless the capacity of the drive motor is increased accordingly. If the strength of the transmission gear is not increased according to the strengthening of No. 5, the transmission gear may be damaged. However, if the capacity of the drive motor is increased and the strength of the transmission gear is increased, the remote control mirror device becomes large and heavy, which increases the manufacturing cost. (2) When the U-shaped spring 5 gets over the screw thread of the male threaded rod 3a when the tilt of the mirror holder 4 reaches the stroke end and is blocked by an external force, a snapping noise is generated. Product value is compromised. The present invention has been made in view of the above circumstances, and in the remote control mirror device, it is not necessary to increase the capacity of the drive motor or the strength of the transmission gear, and the mirror holder resists external force. An object of the present invention is to provide an overload preventing device which can increase the holding force and can prevent the generation of abnormal noise when the tilting of the mirror holder is externally blocked and the transmission is blocked.

[0006]

The basic principle of the present invention created to achieve the above object will be briefly described below with reference to FIG. 6 showing a conventional example. That is, the U-shaped spring 5 sandwiches the male screw rod 3a and serves both as a clutch function for cutting off excessive torque and as a buffering function against external force, but is closer to the drive motor than the U-shaped spring 5 in the transmission direction. Install another weak clutch on the side. The weak clutch is a clutch which is so-called slipping operation because the transmission is cut off by a small rotating torque. Although the type of the clutch is not limited, it is desirable to use a friction clutch in order to perform the sliding operation quietly. If two clutch means are provided in one transmission system as described above, the weaker clutch starts to slip when the rotational torque gradually increases, and the U-shaped spring 5, which is the stronger clutch means, crosses the thread. No noise is generated because it does not operate. As described above, even if two clutches, strong and weak, are provided for the transmission of the rotational force, when an excessive force in the thrust direction acts on the advancing / retreating rod 3, the U-shape is irrelevant regardless of the weak clutch. The spring 5 rides over the thread of the male screw rod 3a and fulfills a cushioning function. As a concrete configuration based on the above-mentioned principle, the overload prevention mechanism of the present invention comprises: a. A mirror holder that is tiltably supported; b. An advancing / retracting rod having a male screw rod whose one end is tiltably attached to the mirror holder; and c. An elastic member that elastically sandwiches the male screw rod of the advancing / retreating rod and acts as a nut, and that, when an excessive force is applied, it overcomes the threads of the male screw rod and acts as a clutch that cuts off the transmission of the excessive force. And d. In a remote control mirror device having a transmission system for transmitting a rotation output of a drive motor to the elastic member, a transmission is interrupted by a sliding operation when a rotational force of a predetermined torque or more is received in the middle of the transmission system. And a predetermined torque for causing the clutch means to perform a sliding operation is smaller than the minimum rotational torque required to cause the elastic member to pass over the screw thread. However, regarding the comparison between the predetermined torque for performing the sliding operation and the minimum necessary rotating torque, there is a reduction gear pair between the clutch means that performs the sliding operation with the predetermined torque and the elastic member, and When the torque increase is inversely proportional, the comparison is made according to the required output torque of the drive motor.

[0007]

According to the above means, in the middle of the transmission system for transmitting the rotational force of the drive motor to the elastic member, it is weaker than the clutch function of the elastic member (for example, U-shaped spring) (sliding operation with a small torque). Since the clutch means is provided, when the drive motor rotates while the mirror holder is prevented from tilting due to an external force, the weaker one of Since the clutch means slides and cuts off the transmission, no operating noise due to screw thread crossing is generated. In this way, overloading of the drive motor and the members of the transmission system can be prevented without producing abnormal noise. In addition, when the mirror holder collides with an obstacle or the advancing / retreating rod receives an excessive force in the thrust direction, the advancing / retreating rod moves in the thrust direction and cushions while bending the elastic member to move over the threads. Perform a function. In this case, the elastic member does not rotate unless the lead angle of the male and female rod of the advancing / retreating rod is equal to or larger than the friction angle, so that the cushioning function is achieved regardless of the strength of the clutch means. In this case, since the weak clutch means provided by applying the present invention does not participate in the cushioning operation, even if the spring constant of the elastic member is set to a large value to increase the drag force against the movement of the advancing and retracting rod in the thrust direction, the weak clutch The overload protection function of the means is not affected. When the spring constant of the elastic member (for example, a U-shaped spring) is set to be large, the elastic member has a large spring constant for advancing and retracting even if the mirror holder is tilted by the wind pressure due to the above-mentioned effects. It is supported by and resists tilting of the mirror holder. Further, when the drive motor rotates while the tilt of the mirror holder is blocked by an external force, the weaker clutch means slides, so overload is prevented regardless of the spring constant of the elastic member. No abnormal noise is generated due to the thread over the elastic member. In this way, since the overload prevention is performed by the weaker clutch means, it is necessary to increase the capacity of the drive motor and the transmission system member even if the spring constant of the elastic member is increased to increase the tilting drag of the mirror holder. There is no.

[0008]

FIG. 2 is a side view showing a drive unit of a remote control mirror device equipped with an embodiment of an overload prevention mechanism according to the present invention, which is partially cut and drawn. The drive unit housing 6 is constituted by the housing body 6a and the housing lid 6b, and the mirror holder 7 is provided with respect to the concave spherical seat 6c formed on the housing lid 6b.
The convex spherical surface 7a is rotatably fitted. In the drive housing 6, a drive motor having a worm gear (both of which are hidden in the drawing, which will be described later with reference to FIG. 3) is installed to rotate the worm wheel 10. The U-shaped spring 5 is the worm wheel 10 described above.
Rotate together with, and screw the advancing / retreating rod 8 in the vertical direction in the figure. One end of the advancing / retreating rod 8 is attached to the mirror holder 7 via a ball joint 9, and the mirror holder 7 is reciprocally tilted as the advancing / retreating rod 8 moves forward and backward. FIG. 3 shows a plan view in which a part of the mirror holder 7 is cut away.

In FIG. 3, the concave spherical seat 6c formed on the housing lid 6b appears at the broken portion of the mirror holder 7. The worm wheel 10 and the ball joint 9 are the components described above with reference to FIG. In FIG. 3, the advancing / retreating rod 8 is hidden by a ball joint 9. A reference numeral 11 indicates a drive motor, and a worm gear 12 fixed to a rotation shaft of the drive motor meshes with the worm wheel 10.

FIG. 4 shows an enlarged detail of a portion drawn as a cut surface in FIG. 2, and FIG. 1 shows an exploded perspective view of main components among the constituent members appearing in FIG. Next, the configuration will be described with reference to FIGS. 1 and 4 together. All the components described with reference numerals in FIG. 1, which is an exploded perspective view, are illustrated in FIG. 4, which is an assembled sectional view. However, the detailed structure shown by adding the alphabetical suffix to the drawing reference number is illustrated in more detail in FIG.
The advancing / retreating rod 8 is a member in which a concave spherical seat 8b is integrally formed at one end of the male screw rod 8a.
It is fitted with the joint ball 7b to form a ball joint 9. The male rod 8a of the advancing / retreating rod 8 is the central hole 1 of the spring holder 13.
It is inserted through 3b. The spring holder 13 is a tubular member having a thick flange-shaped portion 13a, and the flange-shaped portion 13a has a spring insertion hole 13 orthogonal to the central hole 13b.
c is provided, and the U-shaped spring 5 is inserted into the spring insertion hole 13c, and the U-shaped spring clamps the male screw rod 8a. As a result, when the rotational torque transmitted to the U-shaped spring 5 via the spring holder 13 becomes excessive, the U-shaped spring bends in such a manner that the U-shaped spring expands and rides over the screw thread of the male screw rod 8a to run idle. The transmission is cut off. This action is similar to that of a clutch that slips when the torque exceeds a predetermined value.

The tubular portion of the spring holder 13 is inserted into the center hole 21a of the tubular spring holder guide 21, and the engaging notch 13d of the spring holder 13 is formed in the spring holder guide 21.
Is engaged with an engaging projection formed on the inner peripheral surface of the center hole 21a to be locked for relative rotation. Reference numeral 14 denotes an annular leaf spring formed in a curved plate shape, which is compression-inserted between the flange-shaped portion of the spring holder 13 and the upper end surface of the spring holder guide 21 to eliminate play in the thrust direction.

The worm wheel 10 has a cylindrical boss 10a.
The tooth 10b of the worm wheel is integrally molded on the
An inward hook 10c is integrally connected to one end of the cylindrical boss 10a, and a longitudinal split 10d is provided so that the hook 10c can elastically bend. 10e is an inner flange formed at the other end of the cylindrical boss 10a. The spring holder guide 21 is inserted into the tubular boss 10a of the worm wheel from above in the figure, and the clutch spring 15, the clutch drive plate 16, and the clutch driven plate 17 are sequentially inserted from below in the figure. The clutch driven plate 17 is prevented from coming off by the hook 10c of the worm wheel 10. As a result, the clutch spring 15 is compressed and interposed between the inner flange 10e of the worm wheel 10 and the clutch drive plate 16 to press the clutch drive plate 16 toward the clutch driven plate 17 to form a friction clutch. . By appropriately setting the spring load of the clutch spring 15, the transmittable torque of the friction clutch is made relatively small, and the rotational torque smaller than the minimum rotational torque required to cause the U-shaped spring 5 to pass over the thread. The friction clutch is configured to slide. When this configuration is expressed schematically, the friction clutch is a clutch weaker than the clutch function of the U-shaped spring (a clutch having a small transmissible torque).

The engaging claws 16a formed around the clutch drive plate 16 are worm wheels 10.
It engages with the slit 10d provided on the cylindrical boss 10a and is locked for relative rotation. Further, the protrusion 17a protruding inward of the clutch driven plate 17 engages with the engagement notch 21b of the spring holder guide 21 and is locked for relative rotation. When the mirror holder 7 tilts, the joint ball 7b of the mirror holder draws an arc. Therefore, the forward and backward movements of the advancing / retreating rod 3 are accompanied by a slight rotational movement, not a pure parallel movement. In order to adapt to this rotational movement, the spring holder guide 21
A convex spherical surface 21c is formed at the lower end of the figure, and is rotatably guided by a concave spherical seat 6d formed on the bottom wall of the housing body 6b. Reference numeral 18 in the figure is a waterproof cover made of rubber.

(Refer to FIG. 4) The U-shaped spring 5 of this embodiment holds the male screw rod 8a of the advancing / retreating rod 8 by sandwiching it even when the mirror holder 7 receives a large wind pressure so as not to get over the screw thread. The spring constant is set large. However, when the mirror holder 7 collides with an external obstacle and receives an external force larger than the wind pressure, the advancing / retreating rod 8 receives a large force in the thrust direction and pushes the U-shaped spring 5 to spread the U-shaped spring 5 to allow the thrust to pass. It moves in the direction and acts as a buffer. In this way, when the advancing / retreating rod 8 is forcibly moved in the thrust direction, the U-shaped spring 5 receives a force mainly in the expanding direction, and receives little turning force around the male screw rod 8a. Therefore, the magnitude of the torque value that can be transmitted by the friction between the clutch drive plate 16 and the clutch driven plate 17 does not affect the above-mentioned buffer function. By the action similar to the above-mentioned cushioning function, when the force of the hand is directly applied to the mirror holder 4, the U-shaped spring 5 can be screwed over the thread and tilted arbitrarily.

When the worm wheel 10 is rotated by operating a drive motor (not shown), the clutch drive plate 16 is rotated together, and the clutch driven plate 17 is rotated by friction transmission, and the spring holder engaged with the clutch holder plate 17 is rotated. The guide 21 and the spring holder 13 rotate to rotate the U-shaped spring 5 together. As can be easily understood from FIG. 4, the ball joint 9 of the present embodiment has a structure that prevents the advancing / retreating rod 8 from rotating around the axis, and thus the U
By the rotation of the letter-shaped spring 5, the advancing / retreating rod 8 is moved forward and backward in the vertical direction in the figure by a screw feeding action, and the mirror holder 7 is tilted. A technique for automatically stopping the drive motor when the mirror holder 7 reaches the tilt stroke end is known, but there is a problem such as rotation due to inertia of the rotating member, which causes a difference in timing. When the tilting of the mirror holder 7 is blocked by the external force in this way, the transmission is interrupted by the thread over the U-shaped spring 5 in the prior art, but in the present embodiment, the spring of the U-shaped spring 5 is interrupted. Since the constant is large and a relatively weak clutch means is formed between the clutch drive plate 16 and the clutch driven plate 17, the weak clutch means slips before the U-shaped spring 5 crosses the thread. To do. Therefore, there is no possibility of producing abnormal noise due to the thread crossing of the U-shaped spring. Further, the spring constant of the U-shaped spring 5 is increased to improve the wind pressure resistance performance, but it is not necessary to strengthen the constituent members of the drive motor and the transmission system.

FIG. 5 shows an embodiment different from the above, and is an exploded perspective view corresponding to FIG. 1 in the embodiment. The embodiment of FIG. 5 has a configuration in which the spring holder 13 and the U-shaped spring 5 in the embodiment of FIG. 1 are deleted and a spring holder 20 is added. The spring holder 20 of this embodiment has a central hole 20.
The elastic pieces 20b, 20c having a thread-shaped projection of a female screw are integrally formed so as to face the inner peripheral surface of a, and the male screw rod 8a of the advancing and retracting rod 8 is elastically sandwiched. Even with this structure, when an excessive force is applied, the elastic pieces 20b and 20c having the female thread ridges are bent to overcome the thread of the male screw rod, and the above-described embodiment (FIG. 1).
~ The same actions and effects as in Fig. 4) can be obtained. The engagement notch 20d provided in the spring holder 20 is a component that engages with the spring holder guide 21 and locks relative rotation.

[0017]

According to the overload prevention mechanism of the remote control mirror according to the present invention, the slip torque when the elastic member functions as a clutch is provided in the middle of the transmission system for transmitting the rotational force of the drive motor to the elastic member. Since a clutch means that slides with a small torque is provided,
Even if the spring constant of the elastic member is set to a high value, the overload is prevented by the clutch means that slides with the small torque. The action of interrupting the transmission when the torque value becomes excessive is achieved by the slip of the clutch means without depending on the thread crossing operation of the elastic member.
Therefore, there is no possibility that abnormal noise will be generated due to the thread over the elastic member accompanying the operation of cutting off the transmission of the excessive torque. Further, even if the spring constant of the elastic member is set high to increase the supporting force of the mirror holder, it is not necessary to increase the capacity of the drive motor or strengthen the constituent members of the transmission system.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of main constituent members in one embodiment of the present invention.

FIG. 2 is a side view in which a portion of the drive unit in the above embodiment is cut and drawn.

FIG. 3 is a plan view in which a housing lid of the drive unit in the above embodiment is partially cut away and drawn.

FIG. 4 is a detailed view showing an enlarged part drawn by cutting in the side view shown in FIG. 2 above.

FIG. 5 is an exploded perspective view showing an embodiment different from the above and corresponding to FIG. 1 in the embodiment.

FIG. 6 is a cross-sectional side view showing a drive unit of a remote control mirror device according to a conventional example.

FIG. 7 is a perspective view in which a driven gear and a forward / backward rod mounted with a U-shaped spring in the conventional example are extracted and drawn.

[Explanation of symbols]

1 ... Drive unit housing, 1a ... Housing body,
1b ... Housing lid, 2 ... Driven gear, 2a ... Center hole, 2
b ... Spring insertion hole, 3 ... Advance / retract rod, 3a ... Male rod, 3b ...
Joint sphere, 4 ... Mirror holder, 4a ... Concave spherical seat, 5 ... U-shaped spring, 6 ... Drive housing, 6a ... Housing body,
6b ... housing lid, 6c, 6d ... concave spherical surface seat, 7 ... mirror holder, 7a ... convex spherical surface, 7b ... joint ball, 8 ... advancing and retracting rod,
8a ... male rod, 8b ... concave spherical seat, 9 ... ball joint, 10 ...
Worm wheel, 10a ... Cylindrical boss, 10b ... Worm wheel-shaped tooth, 10c ... Hook, 10d ... Split, 1
Reference numeral 0e ... Inner flange, 11 ... Drive motor, 12 ... Worm gear, 13 ... Spring holder, 13a ... Flange portion, 1
3b ... central hole, 13c ... spring insertion hole, 13d ... engagement notch, 14 ... annular leaf spring, 15 ... clutch spring, 1
6 ... Clutch drive plate, 17 ... Clutch driven plate, 17a ... Engagement protrusion, 18 ... Waterproof cover, 2
0 ... Spring holder, 20a ... Center hole, 20b, 20c ... Female threaded elastic piece, 20d ... Engagement notch, 21 ... Spring holder guide, 21a ... Center hole, 21b ... Engagement notch, 21c ... Convex spherical surface.

Claims (1)

[Claims] 1. A method comprising: a. A mirror holder that is tiltably supported; b. An advancing / retracting rod having a male screw rod whose one end is tiltably attached to the mirror holder; and c. An elastic member that elastically sandwiches the male screw rod of the advancing / retreating rod and acts as a nut, and that, when an excessive force is applied, it overcomes the threads of the male screw rod and acts as a clutch that cuts off the transmission of the excessive force. And d. In a remote control mirror device having a transmission system for transmitting a rotation output of a drive motor to the elastic member, a transmission is interrupted by a sliding operation when a rotational force of a predetermined torque or more is received in the middle of the transmission system. And a predetermined torque for causing the clutch means to perform a sliding operation is smaller than a minimum rotation torque required to cause the elastic member to ride over a screw thread. Remote control mirror overload prevention mechanism.