JPH0435239Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention allows the mirror housing to be rotated relative to the mirror base between a normal position and a retracted position that provides the driver with optimal rearward visibility. Regarding retractable door mirrors.

[Conventional technology]

This type of retractable door mirror is equipped with an electric motor and a group of reduction gears inside the mirror housing in order to rotate the mirror housing around an axis fixed to the mirror base, but these are heavy and It has been proposed to use a surface wave motor as a drive source for rotating the mirror housing because the volume of the mirror housing that accommodates these becomes large and the degree of freedom in designing the door mirror is restricted. Such a retractable door mirror is disclosed in Japanese Patent Application No. 60-234596 filed by the applicant of the present application.

FIG. 8 shows a retractable door mirror using a surface wave motor as a driving source.

The mirror housing 12 includes a mirror 14 and is rotatably supported around a shaft portion 16 of a mirror base 10 to be attached to a vehicle body.
A bracket 18 is fixed within the mirror housing 12, and a bearing 24 that supports a portion of the shaft portion 16 is fixed to the upper part of the bracket 18. Shaft 1
A vibrator (stator) and a movable body (rotor) constituting a surface wave motor are coaxially disposed in 6, the vibrator is fixed to a mirror housing, and the movable body is prevented from rotating around the axis by a shaft portion 16. It is placed in a state where The vibrator is an elastic ring 32 and a piezoelectric element 3
4, and the movable body is composed of an elastic ring 32 and a rotor 36 having a rubber slider 38 in contact with it. The contact surface between the elastic ring 32 of the vibrator and the slider 38 of the moving body is pressed by a compression coil spring 42. The compression coil spring 42 is connected to the rotor 36 and the catch seat 44, which is prevented from moving upward on the shaft by the washer 48.
The slider 38 is disposed between the slider 38 and another seat 46 that contacts the surface of the elastic ring 32, and applies a frictional force to the contact surface between the slider 38 and the elastic ring 32.

When a high frequency voltage is applied to the piezoelectric element 34, a traveling wave is formed in the elastic ring 32 due to bending vibration, and the rotor 36 attempts to rotate in a direction opposite to the direction of the traveling wave. Since the rotor 36 is prevented from rotating around the axis, the reaction force causes the elastic ring 32 to rotate around the axis. That is, the mirror housing 12 is designed to be rotated. Such a surface wave motor is lightweight and compact, and has the characteristics of being able to obtain large torque at low speed rotation.
When rotating from the normal position to the storage position or from the storage position to the normal position, an appropriate frictional force is required at the contact surface between the elastic ring 32 and the slider 38.

[Problem that the invention attempts to solve]

However, in the above-mentioned conventional door mirror, when the mirror housing 12 is not rotating, the compression coil spring 42 is considerably compressed in order to cause the elastic ring 32 of the vibrator and the slider 38 of the moving body to act as a friction transmission clutch. A large elastic force is applied to the elastic ring 32 and the slider 38, and a friction force greater than the above-mentioned appropriate friction force is generated on the contact surface between the elastic ring 32 and the slider 38, making it difficult for the mirror housing to rotate smoothly. There are problems in that cases may occur.

An object of the present invention is to provide an improved retractable door mirror using a surface wave motor, which eliminates the problems of the conventional retractable door mirror.

[Means for solving problems]

The present invention includes a member made of a shape memory alloy, which is activated when energized to reduce the spring force acting on the surface wave motor of the spring member, and a member made of the shape memory alloy. The present invention is characterized in that it is configured to energize in synchronization with the surface wave motor and the surface wave motor.

[Effect]

In the present invention, when the mirror housing is in the normal position or the retracted position, a large pressing force is applied by the spring member to the contact surface between the vibrator of the surface wave motor and the moving body, so there is no large impact from the outside. When applied to the mirror housing, the contact surface acts as a sliding clutch, causing the mirror housing to rotate slowly against the frictional force of the contact surface.

In addition, when rotating the mirror housing from the normal position to the retracted position or from the retracted position to the normal position by remote control, the surface wave motor and the member made of the shape memory alloy are energized to rotate the member made of the shape memory alloy. is activated, the spring force of the spring member acting on the surface wave motor is reduced, and a smaller pressing force of the spring member is applied to the contact surface between the vibrator and the moving body, which increases the rotation of the surface wave motor. The influence of the applied spring pressing force can be minimized.

〔Example〕

Hereinafter, embodiments of the retractable door mirror of the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1, reference numeral 10 indicates a base to be fixed to the vehicle body, and a mirror housing 12 including a mirror 14 is rotatably supported by a shaft 16 fixed to the base 10. In the mirror housing 12, a bracket 18 is secured to the bottom of the housing by a screw. An opening through which the shaft 16 is inserted is formed at the bottom of the housing, and a through hole is formed at the top of the bracket 18 to which a bearing 24 that receives a portion of the shaft 16 is fixed. They are arranged in a straight line. Further, a substrate 28 having a central hole approximately the same size as the opening is fixed to the bottom of the mirror housing with a screw, with the shaft 16 inserted therethrough. Reference numeral 32 designates an elastic ring made of, for example, a copper plate. As shown enlarged in FIG. 2, a piezoelectric element 34 is integrated into one surface of the elastic ring 32 to form a surface wave vibrator 40. The vibrator 40 is arranged coaxially with the shaft 16 and fixed to the substrate 28. On the other hand, code 36
Shown is a moving body or rotor, on one surface of which is glued a plastic rubber ring or slider 38 that contacts an elastic ring 32. The rotor 36 can slide in the axial direction with respect to the shaft 16 while its rotation is prevented, and the vibrator 4 is moved by a compression coil spring 42.
It is being pushed towards 0. Codes 44 and 46
is a spring receiver for the spring 42, and the spring receiver 4
4 is prevented from moving upward on the shaft by a washer 48 fixed to the shaft 16, and the spring receiver 46 is connected to the rotor 3.
It is in contact with the surface of 6.

A coil 43 is made of a type of shape memory alloy that contracts when the temperature rises, and is coaxially arranged inside the coil spring 42 . Both ends of the coil 43 are fixed to spring receivers 44 and 46, and the spring receiver 46 receives the contraction force of the coil 43 in the direction of the spring receiver 44 as the temperature rises (energization is applied).
The coil spring 42 is configured to always press the spring receiver 46 against the rotor 36 with a force greater than the contraction force of the coil 43, and by energizing the coil 43, the pressing force exerted by the coil spring 42 on the spring receiver 46 is reduced. do. coil 4
3 is omitted from illustration, but the piezoelectric element 34
It is configured to perform the excitation in synchronization with the excitation of.

As shown in FIG. 3, electrodes 50 and 52 are provided on the surface of the piezoelectric element 34 described above.
A sine wave voltage from the inverter 54 to the electrode 50
V ₀ sinωt is applied, and a cosine voltage V ₀ cosωt with a phase shift of 90 degrees is applied to the electrode 52.
As a result, bimorph-type bending vibration is generated in the piezoelectric element 34 and the elastic ring 32, which becomes a traveling wave and circulates on the ring. The vibrator 40 is fixed to the mirror housing 12, and the rotor 36 is prevented from rotating around the shaft 16, so the reaction force of the rotor 36 causes the mirror housing 12 to move.
will be rotated. Symbol E is the ground electrode for electrodes 50 and 52. By reversing the high frequency voltages applied to the electrodes 50 and 52 using the polarity switch 56, the electrodes 50 and 52 can be rotated in the opposite direction.

A plate 62 having three conductor patterns 60 (60a to 60c) for detecting the rotational position of the mirror housing 12 is fixed to the bearing 24, as shown in FIG. A bridge member 66 having three contacts 64 (64a-64c) contacting each conductor pattern 60 is attached to a cover member 68 secured to the shaft 16 by a speed nut 70. A circuit diagram for detecting the rotational position of the mirror housing 12 is shown in FIG. When the mirror housing is in the normal position, two of the three contacts 64, namely 64a and 64b, contact the corresponding conductor patterns 60a and 60b, respectively;
Contact point 64c is not in contact with conductor pattern 60c. When the switch 72 is turned on in this state, a closed circuit is formed by the power source 74, the switch 72, the relay 76, the conductive pattern 60, the bridge member 66, and the diode 78, and the coil of the relay 76 is excited. The movable contact of this relay 76 is provided as a changeover switch for turning on and off the inverter 54 in FIG. 3, and the inverter 54 is turned on at the same time as the coil of the relay 76 is energized. Further, since the switch 72 and the switch 56 (FIG. 3) are arranged to operate in conjunction with each other, a high frequency voltage of V ₀ sinωt and V ₀ cosωt are applied to the electrode 50 and the electrode 52, respectively. This activates the surface wave motor and rotates the mirror housing from the normal position toward the retracted position (in the direction of arrow B in FIG. 1). When the mirror housing 12 is in the storage position, the contacts 64b of the bridge member 66 are out of contact with the conductor pattern 60b, and the contacts 64c are in contact with the conductor pattern 60c. In this state, since a reverse voltage is applied to the diode 80, no current flows through the coil of the relay 76, the movable contact of the relay 76 returns to the OFF position, and the excitation voltage to the piezoelectric element 34 becomes 0, and the mirror housing 12 stops rotating.

Mirror housing 12 from storage position to normal position
To rotate the switch 72 back (in the direction of arrow A in FIG. 1), turn the switch 72 from the position shown, and the
The 0c bridge member 66, the conductor pattern 60a, the relay 76, and the switch 72 form one closed circuit, and the coil of the relay 76 is energized, which causes the movable contact of the relay 76 to be in the ON position. Since the switch 56 is switched in conjunction with the switch 72, a high frequency voltage of V ₀ cosωt is applied to the electrode 50 of the voltage element 34, and a high frequency voltage of V ₀ sinωt is applied to the electrode 52, and the mirror housing is rotated in the opposite direction. Stops at normal position.

As described above, since the current is applied to the voltage element 34 and current flows through the shape memory alloy coil 43 to raise the temperature of the coil 43, when the mirror housing 12 is rotated, , the coil 43 contracts and the spring receiver 46
(The pressing car coil 4 of the coil spring 42
3 contraction force) will act. As a result, the pressing force applied to the contact surface between the elastic ring 32 of the vibrator and the rubber ring 38 of the rotor 36 is reduced, and the mirror housing 12 can be rotated smoothly.

Furthermore, when the surface wave motor is not operating, the coil 43 returns to its original state, so a large pressing force is applied by the coil spring 42 to the contact surface between the elastic ring 32 and the rubber ring 38.
Acts as a friction transmission clutch.

FIG. 5 shows a second embodiment of the retractable door mirror of the present invention. In the drawings, parts having the same reference numerals as those in the first embodiment indicate the same or similar parts.

In this embodiment, the coil spring 42
The spring receiver 46 is not in direct contact with the rotor 36. That is, a ball bearing 180 is interposed between the spring receiver 46 and the rotor 36,
The inner ring of the ball bearing 180 is in contact with the rotor 36. The inner ring of the ball bearing 180 is allowed to move only in the axial direction and is prevented from rotating around the axis. A substrate 28 and a ball bearing 180 fixed to the bottom of the mirror housing 12
Another coil 182 is interposed between the outer ring and the outer ring. Coil 182 is formed from shape memory alloy wire and does not exert a force on the outer ring of ball bearing 180 in its normal position as shown. Therefore, a large frictional force is applied to the contact surface between the elastic ring 32 and the rubber ring 38 due to the downward pressing force of the compression coil spring 42 . The shape memory alloy that makes up the coil 182 is of a type that expands when the temperature rises, and the coil 182 expands when energized.
The outer ring of the ball bearing 180 is adapted to receive the expansion force upwardly of the shaft. In this embodiment, the stretching force of the coil 182 is smaller than the elastic force of the coil spring 42, so the pressing force exerted by the coil spring 42 on the contact surface is reduced by the stretching force of the coil 182.

It can be seen that the coil 182 is energized in synchronization with the excitation of the piezoelectric element 34, and when the surface wave motor is activated, the pressing force of the coil spring 42 is reduced and transmitted to the contact surface of the surface wave motor. When the piezoelectric element 34 is not excited, i.e. when the mirror housing 1
2 is in the normal position or storage position,
The coil 182 has returned to its original position, and the elastic force of the compression coil spring 42 is applied to the ball bearing 1.
It is transmitted to the rotor 36 via the inner ring 80. At this time, if a large impact is applied to the mirror housing 12 from the outside, the substrate 28 fixed to the mirror housing 12 and the vibrator 40 will be damaged by the shaft 16.
rotate around. At this time, since a large frictional force exists between the rubber ring 38 of the rotor 36 and the elastic body 32 due to the large pressing force of the coil spring 42, the rotation speed of the mirror housing 12 is suppressed. Also ball bearing 180
The outer ring rotates together with the substrate 28, with a coil 182 sandwiched between the outer ring and the substrate 28.

When the stretching force of the shape memory alloy coil 182 described above is greater than the pressing force of the coil spring 42, the seat 46 moves upward in the axial direction when the coil 182 is excited, and the elastic force of the coil spring 42 is applied to the surface wave motor. Since the pressure is not transmitted to the above-mentioned contact surface, it is necessary to construct a structure that pressurizes the contact surface.

FIG. 6 shows a third embodiment of the present invention, in which parts with the same reference numerals as in the first embodiment correspond to the same or similar parts.

The coil spring 4 is indicated by the reference numeral 144.
2 is arranged so as to be movable in the axial direction of the shaft 16. Spring receiver 1
44 is formed into a cylindrical shape having an opening in the center through which the shaft 16 is inserted, and a solenoid 146 is fixed to the inner peripheral surface surrounding the shaft 16. A fixed seat 150 is attached to the shaft 16 between the inner surface of the upper part of the bracket 18 and the spring receiver 144, and a dish-shaped flat spring 148 is attached to the lower end of the fixed seat 150. The tip of the flat spring 148 is the spring receiver 1
44 is pressed downward, and the coil spring 4
2 is held in a compressed state as shown. The fixed seat 150 has a magnetic part such as a stay in the path of the magnetic field lines formed by the solenoid 146, and in this embodiment, the flange part 15
0a corresponds. When the solenoid 146 is energized, it is drawn toward the flange portion 150a, and the spring receiver 144 moves upward against the elastic force of the flat spring 148. The excitation of the solenoid 146 is performed in synchronization with the excitation of the vibrator or piezoelectric element 34, whereby the spring receiver 144 is raised by a certain distance and the pressing force of the coil spring 42 is reduced. This reduces the pressing force applied to the contact surface of the surface wave motor when rotating the mirror housing 12, thereby reducing the influence on the torque generated by the surface wave motor.

FIG. 7 shows a fourth embodiment of the mirror device of the present invention. In the drawings, parts with the same reference numerals as in the third embodiment correspond to the same or similar parts.

In this embodiment, the spring receiver 144 is secured to the shaft 16 by a washer 160. The elastic force of the compression coil spring 42 is set smaller than that in the first, second and third embodiments to provide the minimum pressing force required by the surface wave motor.

Reference numeral 170 denotes a thrust ball bearing, which supports the shaft 1 while being prevented from rotating with respect to the shaft 16.
It is disposed so as to be movable in the axial direction of 6. The flat spring 148 is fixed to the lower end of the thrust ball bearing, and the tip of the flat spring 148 is in contact with the spring receiver 144. When the mirror housing 12 is in its normal position, the elastic force of the flat spring 148 forces the thrust ball bearing 170 against the inner surface of the upper part of the bracket 18, as shown. In other words, the ball portion 170a is pressed while being positioned within the groove on the bracket side. If the mirror housing 12 receives a strong external impact in this position, the bracket 18 will rotate while pressing the thrust ball bearing 170 downward. The maximum travel distance of the sliced ball bearing 170 is the bracket 18.
At that time, since the flat spring 148 is pressing the thrust ball bearing 170 upward, the rolling friction force between the ball portion 170a and the inner surface of the bracket causes the mirror housing 12 to be Rotation speed is suppressed.

Further, when rotating the mirror housing 12 from the normal position to the retracted position by remote control, as in the third embodiment, when the solenoid 146 is excited in synchronization with the excitation of the piezoelectric element 34, the sliced ball bearing 170 is activated by a flat spring. It is attracted to the solenoid 146 against the elastic force of the solenoid 148 and separated from the bracket 18. This allows the surface wave motor to be driven smoothly. The same applies when returning the mirror housing 12 from the storage position to the normal position.

In the embodiment described above, the vibrator 40 is fixed to the mirror housing 12, and the rotor 3 is fixed to the mirror housing 12.
The rotor 36 is fixed to the mirror housing 12, and the vibrator 40 is arranged relative to the shaft 16. The same is true even if In this case, it goes without saying that the elastic body 32 and the slider 38, which is a rubber ring, are arranged so as to be in face-to-face contact with each other.

[Effect of idea]

As explained above, according to the retractable door mirror of the present invention, when the mirror housing is stopped at the normal position or the retracted position, the vibrator of the surface wave motor, which is the drive source, and the spring member are used at the contact surface between the rotor and the surface wave motor. Since there is a large frictional force, it acts as a friction transmission clutch, and when the mirror housing is rotated, the member made of shape memory alloy operates in synchronization with the excitation of the vibrator, and as a result, the pressing force from the spring member is reduced. As a result, the frictional force generated at the contact surface between the vibrator and the rotor is reduced and no longer acts as a friction transmission slatch. Therefore, when the mirror housing rotates, it acts only as a driving source without being affected by the spring member, so that the mirror housing rotates smoothly.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing an embodiment of the retractable door mirror of the present invention, with main parts shown in cross section. Figure 2 is an enlarged sectional view of the vibrator and rotor that make up the surface wave motor, Figure 3 is a driving circuit diagram of the surface wave motor, Figure 4 is a position detection circuit diagram of the mirror housing, and Figures 5 to 7. These are partially cutaway front views showing second, third and fourth embodiments of the present invention, with main parts shown in cross section.
FIG. 8 is a partially cutaway front view showing a conventional retractable door mirror. 10...Base, 12...Mirror housing,
16... Shaft portion, 18... Bracket, 24... Bearing, 32... Elastic ring, 34... Piezoelectric element,
36...Rotor, 38...Rubber ring, 40...
... Vibrator, 42 ... Compression coil spring, 43
... Shape memory alloy coil, 44, 46 ... Spring receiver, 50, 52 ... Electrode, 54 ... Inverter,
56...Switch, 60...Conductor pattern, 62
... Plate, 64 ... Contact, 68 ... Cover member, 72 ... Switch, 76 ... Relay, 78 ...
...Diode, 146...Solenoid, 148...
...Flat spring, 170,180...Ball bearing, 182...Shape memory alloy coil.

Claims (1)

[Scope of utility model registration request] A mirror base, a shaft fixed to the mirror base, a mirror housing rotatably attached to the shaft, a surface wave motor disposed concentrically with respect to the shaft within the mirror housing, and the mirror housing. a spring member disposed inside the surface wave motor and pressing the vibrator of the surface wave motor and the movable body against each other;
In the retractable door mirror in which the mirror housing rotates when the surface wave motor is energized, a member is formed of a shape memory alloy and operates when energized to reduce the spring force of the spring member acting on the surface wave motor. is placed inside the mirror housing,
A retractable door mirror characterized in that the member made of the shape memory alloy and the surface wave motor are energized in synchronization.