JPH0911794A - Tilting mechanism of rearview mirror - Google Patents

Abstract

PURPOSE: To improve the responsiveness of the tilting, and to obtain a desired tilting angle instantly, by arranging in parallel at least two springs of the springs made of an form-memory alloy which are provided at the positions of the upper and the lower, and the left and the right, and furthermore, connecting them in series electrically. CONSTITUTION: Tension springs 10 to 13 made of a form-memory alloy which are used to tilt a mirror in the vertical and the lateral directions are provided parallel forming a set of two springs, at the positions in the up and down, and the left and right, and the two tension springs are connected in seried electrically. That is, the series connection of springs 10a and 10b, the series connection of springs 11a and 11b, the series connection of springs 12a and 12b, and the series connection of springs 13a and 13b, are connected in parallel respectively, each series connection is selected by converting a notch switch 32 as a converting means, and connected with a power source 33. Consequently, when a current is let flow to one of the series connections by operating the notch switch 32, the current is to flow to a pair of tension springs, and the form-memory alloy generates a transformation by the Joule heat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rearview mirror for visually recognizing the rear of a vehicle, and more particularly to a tilting mechanism for arbitrarily tilting the angle of a mirror surface.

[0002]

2. Description of the Related Art Generally, a vehicle rearview mirror such as a door mirror needs to tilt an angle of a mirror surface to a desired position when a driver changes. Therefore, conventionally, a shape memory alloy that can automatically tilt the mirror surface to the left and right and up and down is being adopted. Examples of a shape memory alloy used for adjusting the tilt of the rearview mirror include, for example, Japanese Patent Application Laid-Open No. 61-44044 (Prior Art 1) and Japanese Utility Model Laid-Open No. 60-69745 (Prior Art 2).
Are known. Of these, Conventional Example 1
5, the mirror surface 50 of the rearview mirror will be described later so as to be tilted on two axes 51 and 52 forming orthogonal coordinates with the support origin S as an axis. The first tension spring 5 is pivotally supported by the pivoting means
3, 54 are arranged symmetrically with respect to the origin S on the axis 51,
The second tension springs 55 and 56 are also arranged on the shaft 52 symmetrically with respect to the origin S.

Each of the tension springs 53 to 56 is made of a shape memory alloy which has a natural length when no load is applied at room temperature and transforms into a specific length when heated. In this case, the natural length is longer than the natural length. Is set to be long. That is, when a current is applied to any one of the tension springs 53 to 56, the tension spring is heated by the Joule heat generated by itself, and when the temperature reaches the critical temperature at which the shape memory alloy transforms, the tension spring contracts. However, the mirror surface 50 tilts in this direction. In addition, tension springs 53, 5 arranged on the shaft 51
4 is provided with a switch 57 for selectively passing current, and a tension spring 55, 56 arranged on the shaft 52 is provided with a switch 58 for selectively passing current.
By operating 7, 58, each tension spring 53-56
Can be supplied with current. The tension springs 53, 54, 55 and 56 are not energized when the tiltable electrodes of the switches 57 and 58 are in the neutral position.

The pivoting means for pivotally supporting the mirror surface 50 at the origin S is, as shown in FIG. 6, a support pivot 65 of a mirror base 61 provided on a body 60 and a sliding surface 63 of the support pivot 65. An engaging surface 64 of the pivot plate 62 which is loosely engaged with, a cap support 66 having a ball cap shape provided to press the engaging surface 64 against the sliding surface 63, a tightening screw 67, and a fixed spring 68. The sliding surface 63 and the sliding surface 63 are appropriately pressure-bonded by the fixed spring 68, and are fixed and held at an arbitrary tilted position of the pivot plate 62 to which the mirror surface 50 is attached by frictional resistance generated therebetween. ing. Next, the operation will be described. When no current is applied to each of the tension springs 53 to 56, the pivot plate 62 sandwiched between the support pivot 65 and the cap support 66 is fixed by friction resistance, and thus the mirror surface 50 is formed. Is fixed in this position.

Next, by operating the switch 58, for example, when an electric current is applied to the tension spring 55, the tension spring 55 is heated by Joule heat, and a force for transforming to an intrinsic length is exerted. Then, when sufficient power for transformation is supplied, a tension is generated to pull down the front end portion (where the spring 55 is attached) of the mirror surface 50, whereby the mirror surface 5
0 will tilt. After that, even if the switch 58 is turned off, the other three pieces are caused by the frictional force when the mating surface 64 of the pivot plate 62 is clamped by the cap support 66 and the sliding surface 63 of the support pivot 65 shown in FIG. Until one of the springs 53, 54, 56 of
The mirror surface 50 is configured to stop at this position. Further, the detailed description of the contents described in Conventional Example 2 (Micro Film No. 60-69745 No. Shokai 60-69745) is omitted, but as in the case of Conventional Example 1 described above, one in each of the vertical and horizontal directions of the mirror surface. The shape memory alloy tension springs are arranged and the tension springs are selectively energized to incline the mirror surface in a desired direction.

[0006]

However, in the tilting mechanism of the conventional rear-view mirror described above, the free mating surface 64 of the pivot plate 62 shown in FIG. 6 is formed between the cap support 66 and the sliding surface 63 of the support pivot 65. In order to overcome the frictional force and tilt the mirror 50, a large force is required for tilting. For this reason, a large-sized shape memory alloy spring is required, so that the heat capacity increases, it takes a long time to raise the temperature, and as a result, there is a drawback that responsiveness deteriorates.

Further, since the shape memory alloy has a small electric resistance value, it is necessary to set the power source voltage to be low or to use a voltage dividing resistor to reduce the voltage value applied to the shape memory alloy spring. However, there is a problem that the equipment becomes large. The present invention has been made to solve such a conventional problem, and its object is to:
It is an object of the present invention to provide a tilting mechanism for a rearview mirror, which has good responsiveness when tilting the mirror and does not require peripheral devices such as a voltage dividing resistor.

[0008]

In order to achieve the above object, the present invention has a mirror base and a mirror holder which is tiltably arranged with respect to the mirror base and to which a mirror surface for rearward viewing is attached. In a tilting mechanism of a rearview mirror capable of tilting the mirror holder in a desired direction by tilting the mirror holder with respect to a mirror base, at least two shape memory alloys are provided at upper and lower portions and left and right portions of the mirror holder. The springs are arranged in parallel and connected to the mirror base, and the springs of each part are electrically connected in series, and a switching means for switching connection / disconnection between the series connection of each part and a power source is provided. Is a feature.

[0009]

According to the present invention constructed as described above, at least two springs made of a shape memory alloy are arranged in parallel at each of the upper, lower, left and right positions for tilting the mirror surface. These are electrically connected in series. Therefore, since the force for tilting the mirror surface is at least doubled, the tilt responsiveness is improved and the desired tilt angle can be obtained instantly. The voltage applied to each spring is a voltage obtained by dividing the power supply voltage according to the law of voltage division. Therefore, it becomes possible to apply a desired voltage to each spring without using peripheral devices such as a voltage dividing resistor.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of the inside of a rearview mirror to which a tilting mechanism of the present invention is applied, and FIG. 2 is a sectional view thereof. As shown in FIGS. 1 and 2, the rearview mirror is a mirror base 1 fixed inside a mirror housing (not shown).
A plate pivot 2 which is tiltably attached to the mirror base 1, a cap support 3 which presses and fixes the plate pivot 2 on the mirror base 1, and a plate pivot 2 which is fixed to the plate pivot 2 and works in conjunction therewith. It has a mirror holder 4 that tilts, and a mirror 5 that is fitted and fixed to the mirror holder 4 and that reflects a rear visual field. In the mirror base 1, a cylindrical support pivot 6 is provided upright in the center of a rectangular flat plate 9, and a concave spherical sliding surface 7 is formed on the upper surface side of the support pivot 6. . A stem 8 having a screw hole 8a formed at the upper end is provided upright at the center of the stem 8. Further, mounting grooves 14 to 14 for connecting tension springs 10a, 10b to 13a and 13b made of a shape memory alloy, which will be described later, are formed in a rectangular shape along four side surfaces of the flat plate 9.

The plate pivot 2 includes a mirror holder 4
It is used to fix the robot, and has a bowl-shaped tilting pivot 1 at the center.
5 is formed, and an opening 16 is formed at the center of the tilt pivot 15. Also, plate pivot 2 of 4
Tension springs 10a, 10b-13a, 1 along one side
Mounting grooves 17 to 17 for connecting 3b are formed. The surface of the tilting pivot 15 on the convex portion side is a mating surface 18 that loosely mates with the sliding surface 7 of the support pivot 6.
The sliding surface 18 slides with respect to the sliding surface 7 so that the plate pivot 2 and thus the mirror 5 tilt. Further, the surface of the tilting pivot 15 on the concave portion side is also a mating surface 19 so as to slide on the convex spherical sliding surface 20 of the cap support 3. The plate pivot 2 is made of an insulating material.

The cap support 3 is, as described above,
It has a convex spherical sliding surface 20 and has an opening 21 at the center. And washer 23, spring 2
2, the screw 24 is inserted through the opening 21 of the cap support 3 and the opening 16 of the plate pivot 2, and the screw 24 is screwed into the screw hole 8a of the stem 8 to be fixed. On this occasion,
The spring 22 is supported by the washer 23 and is urged to press the cap support 3 toward the mirror base 1. Tension springs 10a, 10b-13a,
13b is made of a shape memory alloy, and its characteristic length is set shorter than the distance between the flat plate 9 of the mirror base 1 and the plate pivot 2. Also, this tension spring 1
0a, 10b to 13a, 13b are plate pivots 2
And the base mirror 1 are connected to each other and are concentrically arranged, and the tension springs 10a, 10a,
10b, tension springs 11a and 11b, tension springs 12a and 1
2b and tension springs 13a and 13b are arranged in parallel. Then, the tension springs arranged in parallel are short-circuited by the connection lines 25 to 25 at the connection portion with the plate pivot 2. That is, the four tension springs are arranged in parallel and electrically connected in series.

Further, of the tension springs arranged in parallel, the connection portion between one of the tension springs 10a, 11a, 12a, 13a and the mirror base 1 is an insulating portion 26, and the other tension spring 10b, 11b, 12b ,. 13b and mirror base 1
And are still connected. And mirror base 1
Is composed of a conductor, the tension springs 10b, 1
All of 1b, 12b and 13b are short-circuited on the mirror base 1 side. The tension springs 10a to 13a are connected to the wirings 27 to 30 on the side of the connection with the mirror base 1, and the mirror base 1 made of a conductor is connected to the wiring 31. The wirings 27 to 30 are connected to the power supply potential via the switching means, and the wiring 31 is connected to the ground potential. That is, a closed loop is formed in the order of the wiring 27, the tension spring 10a, the connecting wire 25, the tension spring 10b, the base mirror 1, and the wiring 31, and the same closed loop is formed on the other three sides.

This is schematically shown in FIG. 3, in which the tension springs 10a and 10b are connected in series and the tension spring 11 is connected.
The series connection of a and 11b, the series connection of the tension springs 12a and 12b, and the series connection of the tension springs 13a and 13b are respectively connected in parallel, and each series connection is selected by the switching of the notch switch 32 as the switching means, It is connected to the power supply 33. Therefore, when the notch switch 32 is operated to selectively pass a current through one of the series connections, a current flows through the pair of tension springs, and the Joule heat at this time transforms the shape memory alloy. Will be done. Next, the operation of the tilting mechanism of the rearview mirror thus configured will be described. 1 and 2
When no current is supplied to each of the tension springs 10a, 10b to 13a, 13b, the tension springs retain their natural lengths, so that the angle of the mirror 5 does not change at this point.

When the notch switch 32 shown in FIG. 3 is operated to switch the tension springs 10a and 10b so that a current flows in series connection, the tension springs 10a and 10b are connected.
In 10b, Joule heat is generated by the current, the temperature rises, and when it reaches the critical temperature, it transforms in the direction of the intrinsic length. In this case, as described above, the characteristic length is set to be shorter than the distance between the mirror base 1 and the plate pivot 2, so that the force of tilting the left side of the plate pivot 2 in FIG. To do. The force acting at this time is, of course, twice as large as that when one tension spring is used. Further, the voltage applied to each tension spring 10a and 10b is 1/2 of the voltage of the power supply 33 according to the law of voltage division. Therefore, it is not necessary to generate the predetermined voltage required for transforming the shape memory alloy by using the voltage divider resistor or the like, and the rated voltage for the vehicle can be used as it is and connected to the tension spring made of the shape memory alloy. .

In this way, in this embodiment, two tension springs made of a shape memory alloy used for tilting the mirror in the vertical and horizontal directions are arranged parallel to each other in the vertical and horizontal directions, respectively. The two tension springs are configured to be electrically connected in series. Therefore, the mirror 5
The tension applied when tilting is doubled as compared with the case where there is one tension spring, the responsiveness when tilting the mirror 5 is improved, and the mirror 5 instantly tilts to a desired angle.
In addition, the wire diameter of the tension spring can be reduced, and the cost can be reduced. Further, since the voltage applied to the tension spring is halved, it is possible to apply a desired voltage to the tension spring made of each shape memory alloy without using a voltage dividing resistor or the like, which simplifies the device. It is possible to reduce the manufacturing cost. In addition, in the above-described embodiment, an example in which two tension springs are arranged in parallel and electrically connected in series has been described, but the present invention is not limited to this, and three or more tension springs are connected. They may be arranged in parallel and electrically connected in series. Further, when arranging the two tension springs, the two tension springs may be integrally formed as shown in FIG.

[0017]

As described above, according to the present invention,
4 for tilting the mirror vertically and horizontally
Arrange a plurality of shape memory alloy tension springs in parallel,
In addition, these tension springs are electrically connected in series. Then, an electric current is applied to this series connection to cause transformation, and the mirror is tilted. Therefore, the force acting on the tilt becomes significantly larger than that when only one tension spring is used, and the tilt responsiveness is significantly improved. In addition, the voltage applied to each tension spring is equal to the power supply voltage divided by the number of tension springs, so the voltage applied to the shape memory alloy that operates at a voltage lower than the normal power supply voltage is divided into voltage divider resistors, etc. It is not necessary to create it by using, and the number of parts can be reduced.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a configuration of an embodiment of a tilting mechanism of a rearview mirror to which the present invention is applied.

FIG. 2 is a sectional view showing a configuration of an embodiment of a tilting mechanism of a rearview mirror to which the present invention is applied.

FIG. 3 is a wiring connection diagram of a tension spring.

FIG. 4 is an explanatory view showing an example in which two tension springs made of a shape memory alloy are integrally formed.

FIG. 5 is a schematic view showing a conventional rear-view mirror tilting mechanism.

FIG. 6 is a cross-sectional view showing a conventional rear-view mirror tilting mechanism.

[Explanation of symbols]

1 Mirror Base 2 Plate Pivot 3 Cap Support 4 Mirror Holder 5 Mirror (Mirror Surface) 6 Support Pivot 8 Stem 10a, 10b to 13a, 13b Shape Memory Alloy Tension Spring 14, 17 Mounting Groove 15 Tilt Pivot 22 Spring 23 Washer 24 Screw 25 Connection line 26 Insulation 27-31 Wiring 32 Notch switch 33 Power supply

Claims (2)

[Claims] 1. A mirror base, and a mirror holder that is tiltably disposed with respect to the mirror base and has a mirror surface for rearward viewing attached thereto. The mirror surface is tilted with respect to the mirror base. In a tilting mechanism of a rearview mirror capable of tilting in a desired direction, at least two shape memory alloy springs are arranged in parallel at respective parts of the upper and lower parts and the left and right parts of the mirror holder, and while being connected to the mirror base, A tilting mechanism for a rearview mirror, comprising switching means for electrically connecting springs for each part in series and for switching connection / disconnection between the series connection of each part and a power source. 2. The rearview mirror according to claim 1, wherein the two or more shape memory alloy springs provided in each of the portions are arranged on a concentric circle centered on a tilt center of the mirror holder. Tilting mechanism.