JPH04178184A - Switching circuit in driving arrangement - Google Patents

Abstract

PURPOSE:To diminish circuit parts to surely prevent burning of a motor by conducting switching through the use of PTC elements, of which value of resistance rapidly increases as a temperature rises. CONSTITUTION:When a mirror assembly 7 reaches a storage position being a predetermined stopping position, a stopper operates, i.e., a ball 12 on the moving side strikes on the stepped part 61 of a circular groove 6 on the fixed side and the mirror assembly 7 is physically and forcibly stopped in the storage position being the predetermined stopping position. At that time, an overload is applied to a motor 13 and an overcurrent flows through an electric circuit. When the internal temperature of a second PTC element 39 rises by this overcurrent and reaches a certain temperature region, the internal resistance of the second PTC element 39 increases rapidly and the second PTC element 39 conducts a switching operation. As a result, the rotation of the motor 13 stops and the mirror assembly 7 stops completely in the storage position.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a switch circuit in a drive device, and in particular, electrically, the number of circuit components can be reduced, and burnout of the motor can be reliably prevented. Mechanically, the present invention relates to a switch circuit in a drive device that allows the motor and drive force transmission mechanism to be made smaller and smaller in capacity, and that can stop a moving body at a predetermined stop position without rattling.

[Prior Art] A drive device generally includes a power source, a motor connected to the power source via a switch, and a moving body that is linked to the motor via a drive force transmission mechanism and is moved by the drive of the motor. . By operating the switch to energize the motor, the motor is driven, and the driving force of the motor is transmitted to the movable body via the driving force transmission mechanism, so that the movable body moves. Then, at a predetermined stop position, the switch is operated to cut off the power to the motor, thereby stopping the drive of the motor and stopping the movable body at the predetermined stop position.

The drive device described above is used in various devices. For example, it is widely used in electric retractable door mirrors, power windows, power antennas, retractable lamps, and power seats in automobiles, as well as slide devices, rotation devices, opening/closing devices, etc. in other fields.

Many of such drive devices are equipped with a switch circuit that stops the movable body at a predetermined stop position and cuts off power to the motor.

[Problems to be Solved by the Invention] However, the switch circuit in the above-mentioned conventional drive device has many circuit parts electrically, and there is a risk of burning out the motor, and mechanically it has a large number of circuit parts, and mechanically it has a problem with the motor and drive power transmission. There are problems in that the mechanism is large in size and capacity, and it is difficult to stop the moving body at a predetermined stopping position without rattling.

The purpose of the present invention is to electrically require fewer circuit components;
Furthermore, it is possible to reliably prevent motor burnout, mechanically the motor and drive force transmission mechanism can be made smaller and smaller in capacity, and the movable body can be stopped at a predetermined stop position without rattling. An object of the present invention is to provide a switch circuit in a drive device that can perform the following steps.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention aims to reduce temperature by overcurrent generated when a moving object is physically stopped by a stopper or the like and an overload is applied to the motor. When the temperature rises and reaches a certain temperature range, a PTC element whose resistance increases rapidly and switches, and a diode are connected in series as one set, and these two sets are connected in antiparallel. The present invention is characterized in that the switch and the motor are connected in series.

[Operations] The present invention uses PT whose resistance value increases rapidly as the temperature rises.
By performing switching with a C element, the number of circuit components can be reduced compared to one in which switching is performed using a current detection element or the like. Moreover, since the switching is instantaneous, burnout of the motor can be reliably prevented.

In addition, with the above configuration, since the moving object is physically and forcibly stopped by a stopper or the like before the motor drive is stopped, there is no backlash in the drive force transmission mechanism, and as a result, the moving object is free from backlash. It can be stopped at a predetermined stop position without any problems. Moreover, with the above configuration, if the moving object is physically and forcibly stopped at a position other than the predetermined stopping position, the moving object will stop at that position. There is no need for a clutch mechanism or the like to prevent the motor from burning out when the moving body is physically and forcibly stopped at a position other than the predetermined stop position. As a result, it is sufficient for the driving force of the motor to be slightly larger than the movement resistance of the moving body, and therefore the motor and the driving force transmission mechanism can be made smaller and smaller in capacity.

In particular, the present invention has one set in which a PTC element and a diode are connected in series, and these two sets are connected in series between a switch and a motor in an antiparallel state. When a moving object is moved in a certain direction and then moved in the opposite direction, even if one PTC element has a high resistance value as the temperature rises, the other PTC element has a low resistance value at room temperature. Since it is in the value state, the motor can be driven to instantly move the above-mentioned moving body in the opposite direction. In this way, the other PTC element can buy time until the internal temperature of one PTC element decreases and switching operation becomes possible again.

[Embodiment] Hereinafter, an embodiment of a switch circuit in a drive device of the present invention will be described with reference to the accompanying drawings.

This example is an example of application to an electric retractable door mirror of a car.

In the figure, 1 is a mirror base fixed to the vehicle body.

Reference numeral 2 denotes a shaft holder in which a hollow shaft 3 is integrally installed, and this shaft holder 2 is attached to the mirror base 1.
Fixed to. A chamfered portion 4 for stopping rotation is provided on the shaft 3.
, and an engagement groove 5 is provided in the upper end of the shaft 3 in the circumferential direction. A pair of arcuate grooves 6 are provided on the fixing surface of the upper surface of the shaft holder 2 along the arcuate locus of a ball 12 incorporated in the mirror assembly 7 when the mirror assembly 7 (to be described later) is rotated.

As shown in FIG. 6, this arcuate groove 6 has stepped portions 60 and 61 of height H cut at right angles at both ends thereof. The positions of the step portions 60 and 61 at both ends are determined by the use position of the mirror assembly 7 (as shown by the solid line in FIG. 2), which will be described later.
This corresponds to a state in which the mirror assembly 7 protrudes laterally from the vehicle body) and a retracted position (a state in which the mirror assembly 7 is tilted rearward along the vehicle body, as shown by the dashed line in FIG. 2).

Note that the bottom surface of the above-mentioned arcuate groove 6 only needs to be smooth;
For example, it may have a gently upwardly convex shape as shown by the two-dot chain line.

Reference numeral 7 denotes a mirror assembly as a moving body, and this mirror assembly 7 includes a unit bracket 8 rotatably supported on the shaft 3, a mirror housing 9 fixed to the unit bracket 8, and a Yohihower unit 10.
A mirror 11 is attached to the power unit 10 so as to be tiltable vertically and horizontally, and is disposed in the front opening of the mirror housing 9.

A hemispherical recess is provided in the rotating surface of the lower surface of the unit bracket 8 at a location opposite to the arcuate groove 6 of the shaft holder 2, and the ball 12 is fitted into the recess so as to be removable.

When the ball 12 is in contact with the step 60 on the use position side, as shown by the solid line in FIG. 6, the mirror assembly 7 is located at the use position. Further, when the ball 12 is in contact with the stepped portion 61 on the storage position side, as shown by the dashed line in FIG. 6, the mirror assembly 7 is located in the storage position. Furthermore, as shown by the two-dot chain line in FIG. Alternatively, due to buffer rotation, the vehicle is tilted forward along the vehicle body, as shown by the two-dot chain line in FIG.

The stepped portions 60 and 61 at both ends of the arcuate groove 6 and the ball 12 constitute a stopper that physically and forcibly stops the mirror assembly 7 as a moving body at a predetermined stop position. Further, the height H of the stepped portions 60 and 61 of the arcuate groove 6 and the ball 12 are determined by the motor 1 which will be described later.
The stopper should be such that it cannot be run over with the torque of 3, but can be run on with manual or buffer rotation.

Reference numerals 22 and 23 denote protrusions protruding from the fixing surface on the upper surface of the shaft holder 2 and semicircular grooves provided on the rotating surface of the lower surface of the unit bracket 8, so that the protrusion 22 can slide into the groove 23. They are mated.

13 is a motor built into the mirror assembly 7;
This motor 13 is installed on a plate 14 fixed to the unit bracket 8.

This motor 13 is electrically connected to a battery 31 via a switch circuit of the present invention which will be described later.

15 is a clutch mechanism attached to the shaft 3, and this clutch mechanism 15 rotates the mirror assembly 7 manually or when something hits the mirror assembly 7 and rotates the mirror assembly 7 to cushion the impact. When moving the mirror assembly 7, motor 13, and deceleration mechanism 24 (described later) on the movable side, and the mirror base 1 on the fixed side.
, the shaft holder 2 and the shaft 3. The clutch mechanism 15 includes a bush nut 16 fitted onto the shaft 3 in order from above, a compression spring 17, a clutch gear 19, and a clutch holder 2.
0 and washers 18 and 21.

The clutch gear 19 is rotatable with respect to the shaft 3, and has a locking groove on its lower surface. The clutch holder 20 is fixed to the shaft 3 and has a locking claw on its upper surface. The bush nut 16 engages with the engagement groove 5 of the shaft 3 and compresses the compression spring 17. Due to the elastic force of the compression spring 17, the locking pawl on the top surface of the clutch holder 20 locks in the locking groove on the bottom surface of the clutch gear 19, and the clutch gear 19 and the clutch holder 20 are brought into a connected state. be. In addition, the elastic force of the compression spring 17 biases the shaft holder 2 upward via the shaft 3 (on the contrary, the unit bracket 8 is biased downward via the clutch mechanism 15), and as a result, the unit bracket 8 side ball 12
is pressed against the bottom surface of the arcuate groove 6 of the shaft holder 2.

Reference numeral 24 denotes a deceleration mechanism as a driving force transmission mechanism disposed between the clutch mechanism 15 and the motor 13. This deceleration mechanism 24 includes a first worm 25 attached to the output shaft of the motor 13; a first worm wheel 26 meshed with the second worm wheel 26, and a second worm 27 with one end of the rotating shaft mounted in the central through hole of the first worm wheel 26 with a D-cut surface so as to be movable in the axial direction but not rotatable; A second worm wheel 28 meshed with the second worm wheel 27, a gear 29 on the motor side coaxially fixed to the second worm wheel 28, and a gear 29 on the motor side.
An idle gear 30 is interposed between the clutch gear 9 and the clutch gear 19. That is, this idle gear 30 is engaged with the gear 29 on the motor side and the clutch gear 19.

The speed reduction mechanism 24 includes the unit bracket 8 and the plate 14 fixed to the unit bracket 8.
and is supported by a support 32 attached to the plate 14 with screws 33.

Further, the shaft 3. Motor 13. Keratchi mechanism 15
The deceleration mechanism 24 and the like are connected to a gear case portion 44 provided on the unit bracket 8 and the gear case portion 44.
It is covered by a lid 45 fitted and attached to the upper opening of the.

The operation of the electrically retractable door mirror configured as described above will be described below.

First, the motor 13 is driven. Then, that motor 1
The rotational force (driving force) of No. 3 is transmitted to the idle gear 30 via the two-stage worm gear and the gear 29 on the motor side. Here, since the clutch gear 19 and the clutch holder 20 are in an engaged state, the clutch gear 19 is in a fixed state. As a result, the idle gear 30 revolves around the clutch gear 19 while rotating. As the idle gear 30 revolves, the mirror assembly 7 moves by an angle θ with respect to the shaft 3 of the mirror base 1, and the mirror assembly 7 rotates from the use position to the storage position or from the storage position to the use position. Displace. At this time, the balls 12 on the side of the mirror assembly 7 and the unit bracket 8 are transferred along the arcuate grooves 6 on the side of the mirror base 1 and the shaft holder 2 in the direction of the arrow or in the convex direction. And the ball 1 mentioned above
2 hits the stepped portion 60 or 61 of the arcuate groove 6, a switch circuit of the present invention, which will be described later, is activated, the drive of the motor 13 is stopped, and the mirror assembly 7 is moved to a predetermined stop position, that is, the use position. Or stop in the retracted position.

In addition, if an obstacle or the like hits the mirror assembly 7 with a force greater than the elastic force of the compression spring 17 while the mirror assembly 7 is in the use position, or if the mirror assembly 7 is manually moved when taking it into or out of the garage. When rotated with a force greater than the elastic force of the compression spring 17, the clutch gear 19 of the clutch mechanism 15 and the clutch holder 20
is disconnected, the clutch gear 19 rotates relative to the shaft 3, and the mirror assembly 7 accordingly rotates from the use position to the storage position, or from the storage position to the use position, and further from the use position to the front. Tilt the angle φ to .

FIG. 1 is an electrical circuit diagram showing an embodiment of a switch circuit in a drive device according to the present invention.

In the figure, 31 is a battery as a power source, and this battery 31 is a normal DC 12 installed in a car.
It is a V battery.

37 is a switch located on the driver's seat; this switch 37
is a switch for changing the polarity, and in this example, a 3-position changeover switch with two movable contacts is used. This switch 37 includes a first movable contact 371 and a second movable contact 372 that are interlocked, a first common contact COMI and a second common contact COMC0M2, and a first + contact A1 and 2nd + contact A2
and a first electrode connected to one pole of the battery 31, respectively.
- contact B1 and second - contact B2, and first intermediate contact C1
and a second intermediate contact C2.

This switch 37 is configured such that the movable contactor 37
1 and 372 are in contact with the middle contacts C1 and C2.

13 is the motor, and this motor 13 is connected to the switch 3.
Connect in series to 7. That is, one terminal of the motor 13 is connected to the first common contact COMI of the switch 37, and the other terminal of the motor 13 is connected to the second common contact C0M2 of the switch 37.

Reference numerals 38 and 39 indicate a first PTC element and a second PTC element that utilize resistance-temperature characteristics, and these PTC elements 38 and 39 are, for example, polymer-based PTC elements (stock products) that exhibit switching characteristics in which the resistance value changes rapidly in a certain temperature range. Use Polyswitch (product name: Polyswitch) from the company Raycum. This P.T.
The C elements 38 and 39 are arranged so that the mirror assembly 7 as a movable body
2) is an overcurrent that occurs when the motor 13 is physically and forcibly stopped and an overload is applied to the motor 13.
When the internal temperature rises and reaches a certain temperature range, the internal resistance value increases rapidly and a switching operation is performed.

41 and 42 are a first diode and a second diode for rectification. The first diode 41 and the second diode 42 are connected to the first PTC element 38 and the second PT
The C elements 39 are respectively connected in series, and these elements are connected in series between the motor 13 and the switch 37 in an antiparallel state. That is, the first diode 41
the cathode of the motor 13 to the other terminal of the motor 13;
The anode of the diode 41 is connected to one terminal of the first PTC element 38, and the other terminal of the first PTC element 38 is connected to the second common contact C0M2 of the switch 37, respectively. Further, one terminal of the second PTC element 39 is connected to the other terminal of the motor 13, and the second PTC element 39 is connected to the other terminal of the motor 13.
9 is connected to the anode of the second diode 42, and the cathode of the second diode 42 is connected to the switch 3.
7, respectively, to the second common contact C0M2.

Next, the operation of the above-mentioned electric circuit will be explained.

First, operate the switch 37 and its movable contact 371
and 372 are brought into contact with ten contacts A1 and one contact B2, respectively. Then, the current from the battery 31 flows in the direction of the solid line arrow from the motor 13 to the second PTC element 39 to the second diode 42, and the motor 13 rotates (forward rotation), and the rotational force of the motor 13 causes the electric current to flow as described above. The mirror assembly 7 is rotated, for example, from a use position to a storage position. Then, when the mirror assembly 7 reaches a predetermined stop position, that is, the retracted position, the stopper is actuated.
At this time, the mirror assembly 7 is physically forced to stop at a predetermined stop position, ie, a storage position. At this time, an overload is applied to the motor 13, and an overcurrent flows in the electric circuit. This overcurrent causes the second PTC element 3
9 rises and reaches a certain temperature range, the second
The internal resistance of the PTC element 39 increases rapidly, and this second PT
C element 39 performs a switching operation.

As a result, the rotation (drive) of the motor 13 stops, and the mirror assembly 7 completely stops at the retracted position. Therefore, the operation of the switch 37 is stopped, and the movable contacts 371 and 372 are automatically returned to the intermediate contacts C1 and C2.

Next, operate the switch 37 so that the movable contact 371
and 372 are brought into contact with one contact B1 and ten contacts A2, respectively. Then, the current from the battery 31 flows in the direction of the dashed line arrow from the first PTC element 38 to the first diode 41 to the motor 13, the motor 13 rotates (reversely), and the rotational force of the motor 13 causes the above-mentioned operation. Then, the mirror assembly 7 is rotated, for example, from the storage position to the use position.

Then, when the mirror assembly 7 reaches a predetermined stop position, that is, the use position, the stopper is actuated, that is, the ball 12 on the movable side moves against the stepped portion of the arcuate groove 6 on the fixed side.
0, the mirror assembly 7 is physically and forcibly stopped at the use position, which is a predetermined stop position.

At this time, an overload is applied to the motor 13, and an overcurrent flows through the electric circuit. This overcurrent causes the internal temperature of the first PTC element 38 to rise, and when it reaches a certain temperature range, the internal resistance of the first PTC element 38 increases rapidly, and this first PTC element 38
The TC element 38 performs a switching operation. As a result, the rotation (drive) of the motor 13 is stopped and the mirror assembly 7 is stopped.
comes to a complete stop in the operating position. Therefore, the operation of the switch 37 is stopped, and the movable contacts 371 and 372 are automatically returned to the intermediate contacts C1 and C2.

As described above, the switch circuit of the present invention in this embodiment has a first PTC whose resistance value increases rapidly as the temperature rises.
Since the element 38 and the second PTC element 39 perform the switching operation, the number of circuit components can be reduced compared to the case where the switching is performed using a current detection element or the like. Moreover, since the above-mentioned switching operation is instantaneously performed, burnout of the motor 13 can be reliably prevented.

Moreover, the switch circuit of the present invention in the above-mentioned embodiments is as follows:
The mirror assembly 7 as a moving body is connected to stoppers 12 and 6.
After physically and forcibly stopping motor 13 at 0.61
Therefore, there is no backlash in the gear group of the speed reduction mechanism 24 as a driving force transmission mechanism. As a result, the mirror assembly 7 can be consistently stopped at a predetermined stop position, that is, the use position or the storage position. Moreover, if the rotating mirror assembly 7 is physically and forcibly stopped at a position other than the predetermined stop position, the mirror assembly 7
is stopped at that position by the above-mentioned switch circuit of the present invention, so that the motor 13 is prevented from being burnt out if the rotating mirror assembly 7 is physically and forcibly stopped at a position other than the predetermined stop position. This eliminates the need for a clutch mechanism. As a result, it is sufficient that the driving force of the motor 13 is slightly greater than the rotational resistance of the mirror assembly 7, that is, the resistance of the ball 12 moving along the arcuate groove 6. Therefore, the motor 13 and the speed reduction mechanism 24 can be made smaller and have a smaller capacity.

Further, since the clutch torque of the buffering clutch mechanism 15 can be increased independently from the torque of the motor 13, the mirror assembly 7 can be held without play.
As a result, there is no possibility that the image reflected on the mirror 11 will be blurred.

In particular, the switch circuit of the present invention has one set in which the PTC elements 38 and 39 and the diodes 41 and 42 are connected in series, and these two sets are connected in antiparallel to the switch 37 and the motor 13. Since the PTC elements 38 or 39 are connected in series between them, when the mirror assembly 7 is rotated in one direction and then rotated in the opposite direction, one of the PTC elements 38 or 39 will not heat up as the temperature rises. Even if it is in the state of resistance value, the other PTC element 39
Since the mirror assembly 38 is in a low resistance state at room temperature, the motor 13 can be driven to instantly rotate the mirror assembly 7 in the opposite direction. In this way, one PTC element 3 is controlled by the other PTC element 39 or 38.
It is possible to buy time until the internal temperature of 8 or 39 decreases and switching operation becomes possible again.

In the above embodiment, the steps 60 and 61 of the arcuate groove 6 and the ball 12 are used as the stopper, but other techniques may be used.

Further, in the above-mentioned embodiment, an electric retractable door mirror for an automobile was described, but the present invention can also be used as a switch circuit for other drive devices.

[Effects of the Invention] As is clear from the above, since the switch circuit in the drive device of the present invention performs switching using a PTC element whose resistance value rapidly increases as the temperature rises, switching is performed using a current detection element or the like. It requires fewer circuit components compared to other methods. Moreover, since the switching is instantaneous, burnout of the motor can be reliably prevented.

In addition, since the motor is stopped after the moving object is physically and forcibly stopped using a stopper or the like, there is no backlash in the drive force transmission mechanism, and as a result, the moving object can be held at a predetermined stopping position without rattling. can be stopped. Furthermore, if a moving object is physically and forcibly stopped at a position other than the predetermined stopping position, the moving object is configured to stop at that position. There is no need for a clutch mechanism or the like to prevent the motor from burning out when the moving body is physically and forcibly stopped at a position other than the predetermined stop position. As a result, it is sufficient for the driving force of the motor to be slightly larger than the movement resistance of the moving body, and therefore the motor and the driving force transmission mechanism can be made smaller and smaller in capacity.

In particular, the switch circuit of the present invention has one set in which a PTC element and a diode are connected in series, and these two sets are connected in series between the switch and the motor in an antiparallel state. However, when a moving object is moved in a certain direction and then moved in the opposite direction,
Even if one PTC element has a high resistance value as the temperature rises, the other PTC element has a low resistance value at room temperature, so the motor is driven to instantly move the above-mentioned moving object in the opposite direction. It can be moved. In this way, the other P
By using the TC element, it is possible to buy time until the internal temperature of one PTC element decreases and switching operation becomes possible again.

[Brief explanation of the drawing]

The accompanying drawings show an embodiment of the switch circuit in the drive device of the present invention, FIG. 1 is an electric circuit diagram of the switch circuit of the present invention, and FIGS. 2 to 6 are diagrams of an automobile equipped with the switch circuit of the present invention. An electric retractable door mirror is shown, FIG. 2 is a partially cutaway plan view, FIG. 3 is a sectional view showing the motor, drive force transmission mechanism, and moving body assembled, and FIG. 4 is an exploded perspective view. 5 is a view in the direction of the V arrow in FIG. 4, and FIG. 6 is a developed view along the Vl-VT line in FIG. 1... Mirror base, 2... Shaft holder, 3...
...Shaft, 6...Circular groove, 7...Mirror assembly (moving body), 8...Unit bracket, 12
...Ball (stopper), 13...Motor, 15...
・Clutch mechanism, 24... Reduction mechanism (driving force transmission mechanism), 31... Battery (power supply), 37... Switch, 38 and 39... PTC element, 41 and 42
...Diode, 60 and 61...Step part (stopper).

Claims (1)

[Claims] 1. A drive device comprising a power source, a motor connected to the power source via a switch, and a movable body linked to the motor via a drive force transmission mechanism and moved by the drive of the motor, wherein the movable body is This is an overcurrent that occurs when the motor is overloaded by being physically stopped by a stopper, etc., and when the temperature rises and reaches a certain temperature range, the resistance value increases rapidly and the PTC element performs a switching operation. ,
A switch circuit for a drive device, characterized in that one set includes diodes connected in series, and these two sets are connected in series between the switch and the motor in an antiparallel state.