JP2557691Y2 - Switch circuit in drive unit - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a switch circuit in a drive device, and in particular, a switch in a drive device that requires less circuit components and can reduce a durable load of a PTC element. It is related to the circuit.

2. Description of the Related Art A driving device generally includes a power supply, a motor connected to the power supply via a switch, and a moving body which is linked to the motor via a driving force transmission mechanism and moves by driving the motor. . When the switch is operated to energize the motor, the motor is driven, and the driving force of the motor is transmitted to the moving body via the driving force transmitting mechanism, and the moving body moves. Then, at a predetermined stop position, by operating the switch to cut off the power supply to the motor, the driving of the motor is stopped, and the moving body stops at the predetermined stop position.

The driving device described above is used in various devices. For example, electric retractable door mirrors in automobiles, power windows, power antennas, retractable lamps, power seats, and sliding devices in other fields,
Widely used for rotating devices, opening and closing devices, etc.

Many of such driving devices are provided with a switch circuit that stops the moving body at a predetermined stop position and cuts off the power supply to the motor.

As the switch circuit in the above-described drive device, there is, for example, a switch circuit described in Japanese Patent Application Laid-Open No. 1-158803 and Japanese Patent Application No. 60-5365 (Japanese Utility Model Application Laid-Open No. 61-122134).

In the former switch circuit, when the extension or contraction of the rod antenna (10) is locked, the motor current sharply rises, and accordingly, the voltage across the PTC (24) rises and reaches a predetermined threshold. Instantaneous logic circuit (AND gate (2
0) and a flip-flop (21) and an AND gate (22) operate the motor stopping means (transistor (23)) to stop the motor (M).

In the latter switch circuit, a rotational position detecting circuit of the mirror housing (12) is configured by a contact holder (21), a brush (22) for energization, a disk (23), a conduction pattern, and the like. When the switch (4) is turned on, the relay (3) is excited, the relay contacts (3a-3b) are turned on, the motor (5) rotates forward or reverse, and the mirror housing (12) is moved to the retracted position. Or, it rotates to the set position. When the mirror housing (12) rotates to a position just before the storage position or the set position, the control unit (2) (mirror housing rotation position detection circuit) is operated, and the relay (3) is activated.
Is demagnetized, the relay contacts (3a-3b) are turned off,
The motor (5) stops and the mirror housing (12) is retracted or set.

[Problem to be solved by the invention] However, the above-mentioned conventional switch circuit is a PTC
Since a logic circuit that operates the transistor (23) by increasing the voltage between both ends of (24) is required, there are problems such as a large number of circuit components.

In addition, the latter switch circuit is a mirror housing (1
2) Control unit (2) (mirror housing rotation position detection circuit) and relay (3) and relay contact (3a-3b) for stopping the storage position or set position
And an overcurrent protection circuit (7) for preventing the motor (5) from burning when an external current is applied to the mirror housing (12) during rotation of the mirror housing (12) and an overcurrent occurs. Since they are required separately, there are problems such as a large number of circuit components. In addition, in the latter switch circuit, the relay contacts (3a-3b) of the relay (3) are not turned off even if the overcurrent protection circuit (7) is activated when an overcurrent occurs, so that the overcurrent protection circuit ( 7), a current always flows, and there is a problem in durability of the overcurrent protection circuit (7).

The purpose of this invention is to reduce the number of circuit components
It is an object of the present invention to provide a switch circuit in a driving device that can reduce a durable load of an element.

[Means for Solving the Problems] The present invention relates to an overcurrent generated when a moving body is physically stopped by a stopper or some other cause and an overload is applied to a motor. A PTC element that performs a switching operation by rapidly increasing its resistance value in a certain temperature range, and is a PTC element connected in series between a switch and the motor.
A C element, a relay coil of a relay circuit that is demagnetized by a switching operation of the PTC element, a relay coil of a relay circuit connected in series with the PTC element, and connected in parallel with the motor, The motor and the PT
A relay contact of a relay circuit that cuts off current to the C element, the relay contact being connected in parallel with the relay coil, and being connected in series to the motor and the PTC element; and A starting capacitor for activating the relay coil and exciting the relay coil, the starting capacitor being connected in series with the relay coil and the PTC element, and being connected in parallel with the relay contact and the motor; and A self-holding resistor for holding an excitation state of a coil, a relay connected in series with the relay contact and the relay coil and the PTC element, and connected in parallel with the motor and the starting capacitor. And a self-holding resistor.

[Operation] According to the present invention, when the moving body is stopped by the above structure, an overload is applied to the motor and an overcurrent is generated. The overcurrent causes the PTC element to perform a switching operation. The relay contact operates to cut off the power supply to the motor and the PTC element.

As described above, in the present invention, the switching operation of the PTC element operates the relay contact of the relay circuit to cut off the power supply to the motor, so that the logic circuit is activated by an increase in the voltage across the PTC (24). , Transistor (2
As compared with the former switch circuit in which the motor (M) is stopped by operating 3), the number of circuit components is reduced.

In addition, in the present invention, the moving body is stopped by the operation of the PTC element and the relay contact of the relay circuit when the moving body is in a predetermined position and in an abnormal state (when an external force is applied). A single circuit (PTC element, relay circuit) is used to stop the motor and to prevent motor burnout due to overcurrent caused by external force applied to the moving body while moving. Therefore, the control unit (2) (mirror housing rotation position detecting circuit) for stopping the mirror housing (12) at the retracted position or the set position, the relay (3) and the relay contacts (3a-3b), and the mirror housing ( An overcurrent protection circuit (7) for preventing burnout of the motor (5) when an external current is applied to the mirror housing (12) during rotation of the mirror (12) and an overcurrent occurs, must be provided separately. Compared with the required latter switch circuit, the number of circuit components is reduced.

Furthermore, when an overcurrent occurs, the energization of the PTC element is completely cut off by the operation of the PTC element and the relay contact of the relay circuit, and the current does not completely flow through the PTC element. The endurance load of the PTC element can be reduced as compared with the latter latter switch circuit in which an overcurrent flows in the protection circuit (7).

In addition, since the operation and self-holding of the relay circuit need only be performed by the starting capacitor and the relay self-holding resistor, a simple circuit configuration is sufficient and the cost is low. [Embodiment] An embodiment of the switch circuit in the drive device according to the present invention will be described below with reference to the accompanying drawings.

This example is an example applied to an electric retractable door mirror of an automobile.

In the figure, reference numeral 1 denotes a mirror base fixed to a vehicle body.

Reference numeral 2 denotes a shaft holder in which a hollow shaft 3 is integrally implanted. The shaft holder 2 is fixed to the mirror base 1. The shaft 3 is provided with a chamfer 4 for stopping rotation, and an engaging groove 5 is provided at an upper end of the shaft 3 in a circumferential direction. A pair of arc-shaped grooves 6 are provided on the fixed surface on the upper surface of the shaft holder 2 along the arc trajectory of the ball 12 incorporated in the mirror assembly 7 when the mirror assembly 7 described later is rotated.

As shown in FIG. 6, the arc-shaped groove 6 has step portions 60 and 61 having a height H cut at right angles at both ends thereof. The positions of the step portions 60 and 61 at both ends are determined based on a use position of the mirror assembly 7 described later (a state in which the mirror assembly 7 protrudes laterally from the vehicle body as shown by a solid line in FIG. 2) and a storage position ( (A state in which the mirror assembly 7 is tilted rearward along the vehicle body, as shown by a one-dot chain line in FIG. 2).

Note that the bottom surface of the above-described arc-shaped groove 6 only needs to be smooth, and for example, may have a gently upward convex shape as shown by a two-dot chain line.

Reference numeral 7 denotes a mirror assembly as a moving body. The mirror assembly 7 includes a unit bracket 8 rotatably supported by the shaft 3, a mirror housing 9 and a power unit 10 fixed to the unit bracket 8.
Attached to this power unit 10 so that it can tilt up, down, left and right,
And a mirror 11 disposed at a front opening of the mirror housing 9.

A hemispherical concave portion is provided at a position facing the arc-shaped groove 6 of the shaft holder 2 in the rotation surface of the lower surface of the unit bracket 8, and the ball 12 is rollably fitted into the concave portion.

When the ball 12 hits the step 60 on the use position side as shown by a solid line in FIG. 6, the mirror assembly 7 is at the use position. Also, this ball 12 is the sixth
As shown by the one-dot chain line in the figure, the mirror assembly 7 is located at the storage position when it hits the step 61 on the storage position side. Further, as shown by a two-dot chain line in FIG. 6, when the ball 12 rides up from the arc-shaped groove 6 in the direction of arrow A and is positioned on the fixed surface of the shaft holder 2, the mirror assembly 7 is manually operated. Alternatively, it is in a state of being tilted forward along the vehicle body as indicated by a two-dot chain line in FIG.

Steps 60 and 61 at both ends of the arc-shaped groove 6 and the ball 12
Constitutes a stopper for physically and forcibly stopping the mirror assembly 7 as a moving body at a predetermined stop position. The step portions 60 and 61 of the arc-shaped groove 6 are also provided.
The height H and the ball 12 are stoppers that cannot be run by the torque of the motor 13 described later, but can be run by manual or shock-absorbing rotation.

Reference numerals 22 and 23 denote protrusions projecting from the fixed surface on the upper surface of the shaft holder 2 and semicircular grooves provided on the rotation surface on the lower surface of the unit bracket 8, respectively.
23 is slidably fitted.

Reference numeral 13 denotes a motor built in the mirror assembly 7,
The motor 13 is mounted on a plate 14 fixed to the unit bracket 8. The motor 13 is electrically connected to the battery 31 via a switch circuit according to the present invention described later.

Reference numeral 15 denotes a clutch mechanism mounted on the shaft 3. The clutch mechanism 15 manually rotates the mirror assembly 7, or rotates the mirror assembly 7 to buffer the mirror assembly 7 when something hits the mirror assembly 7. For example, the edge between the moving-side mirror assembly 7, the motor 13, and a speed reduction mechanism 24 described later, and the fixed-side mirror base 1, the shaft holder 2, and the shaft 3 are cut off. The clutch mechanism 15 includes a push nut 16 fitted to the shaft 3 in order from the top, a compression spring 17,
Clutch gear 19, clutch holder 20, and washer 18
And 21.

The clutch gear 19 is rotatable with respect to the shaft 3, and has a locking groove on the lower surface. The clutch holder 20 is fixed to the shaft 3 and has a locking claw on the upper surface. The push nut 16 is mounted on the shaft 3
And the compression spring 17 is compressed. Due to the elastic force of the compression spring 17, the locking claw on the upper surface of the clutch holder 20 is locked in the locking groove on the lower surface of the clutch gear 19, and the clutch gear 19 and the clutch holder 20 are connected. is there. In addition, the elastic force of the compression spring 17 urges the shaft holder 2 upward through the shaft 3 (inversely, the unit bracket 8 downward through the clutch mechanism 15). The ball 12 is pressed against the bottom of the arc-shaped groove 6 of the shaft holder 2.

Reference numeral 24 denotes a reduction mechanism as a driving force transmission mechanism disposed between the clutch mechanism 15 and the motor 13. The reduction mechanism 24 includes a first worm 25 attached to an output shaft of the motor 13, and a first worm 25. First worm wheel meshed with
26, a second worm 27 in which one end of a rotating shaft is axially movably and non-rotatably mounted in a central through hole of the first worm wheel 26 by a D-cut surface, and the second worm
27 and a second worm wheel 28 meshed with
Motor side gear 29 fixed coaxially to worm wheel 28
The idle gear 30 is interposed between the gear 29 on the motor side and the clutch gear 19. That is, the idle gear 30 meshes 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 a support 32 attached to the plate 14 with a screw 33.

The shaft 3, the motor 13, the latch mechanism 15, the reduction mechanism 24, and the like are provided with a gear case 44 provided on the unit bracket 8 and a lid 45 fitted and attached to an upper opening of the gear case 44. And more covered.

Hereinafter, the operation of the electric retractable door mirror configured as described above will be described.

First, the motor 13 is driven. Then, the motor 13
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 a spliced state, the clutch gear 19 is in a fixed state. As a result, the idle gear 30 revolves while rotating around the clutch gear 19. As the idle gear 30 revolves, the mirror assembly 7 rotates by an angle θ with respect to the shaft 3 of the mirror base 1, and the mirror assembly 7 moves from the use position to the storage position or from the storage position to the use position. Rotationally displaces. At this time, the ball 12 on the mirror assembly 7 or the unit bracket 8 rolls along the arc-shaped groove 6 on the mirror base 1 or the shaft holder 2 in the direction of arrow B or C. And the above-mentioned ball 12 is a step of the arc-shaped groove 6.
When it hits 60 or 61, the switch circuit of the present invention described later is operated, the driving of the motor 13 is stopped, and the mirror assembly 7 is stopped at a predetermined stop position, that is, a use position or a storage position.

Also, when an obstacle or the like hits the mirror assembly 7 with a force greater than the elastic force of the compression spring 17 in a state where the mirror assembly 7 is in the use position, or when the mirror assembly 7 is moved in and out of the garage, the mirror assembly 7 is manually moved. When the clutch spring 19 is rotated with a force larger than the elastic force of the compression spring 17, the clutch gear 19 of the clutch mechanism 15 and the clutch holder 20 are disconnected, and the clutch gear 19 rotates with respect to the shaft 3, and the mirror assembly 7 is accordingly rotated. Rotates from the use position to the storage position, or from the storage position to the use position,
In addition, the angle φ is tilted forward from the use position.

FIG. 1 is an electric circuit diagram showing one embodiment of a switch circuit in the driving device according to the present invention.

In the figure, reference numeral 31 denotes a battery as a power supply, and this battery 31 is a normal DC 12 V battery mounted on an automobile.

Reference numeral 37 denotes a switch arranged in the driver's seat. This switch 37 is a switch for switching the polarity. In this example, a three-position changeover switch linked to two movable contacts is used. This switch
37 is a first movable contact 371 and a second movable contact 372 which are linked to each other, and a first common contact COM1 and a second common contact COMCOM2
And the first + connected to the + pole of the battery 31 respectively.
A contact A1 and a second + contact A2, and a first contact B1 and a second contact B2 connected to the negative pole of the battery 31, respectively.
And a first middle contact C1 and a second middle contact C2.
In this switch 37, the movable contacts 371 and 372 normally contact the middle contacts C1 and C2.

Reference numeral 13 denotes the motor, and the motor 13 is connected to the switch 37 in series. That is, one terminal of the motor 13 is connected to the first common contact COM1 of the switch 37, and the other terminal of the motor 13 is connected to the second common contact COM2 of the switch 37.

38 is a PTC element using the resistance temperature characteristic.
38 uses a polymer-based PTC element (trade name PolySwitch, manufactured by Raychem Corporation) that exhibits switching characteristics in which the resistance value changes abruptly in a certain temperature range. This PTC element 3
8 is connected in series between the motor 13 and the switch 37. That is, one terminal of the PTC element 38 is connected to the motor 1
The other terminal of the PTC element 38 is connected to the other terminal of 3 and the second common contact COM2 of the switch 37, respectively. This PTC
The element 38 is an over-current generated when the mirror assembly 7 as a moving body is physically and forcibly stopped by stoppers (steps 60, 61 and the ball 12) or the like and the motor 13 is overloaded. The current causes the internal temperature to rise, and in a certain temperature range, the internal resistance value sharply increases to perform a switching operation. The PTC element 38 is bipolar.

40 is a relay circuit, this relay circuit 40 is a relay 400
, A normally open relay coil 401, a common contact COM, an A contact, and a B contact. The common contact COM of the relay 400 is connected to the first common contact COM1 of the switch 37,
400 B contacts are connected to one terminal of the motor 13, respectively. One terminal of the relay coil 401 is connected between the common contact COM of the relay 400 and the first common contact COM1 of the switch 37 via the capacitor 46, and the other terminal of the relay coil 401 is connected to the PTC element 38. And the motor 13 respectively.

Reference numeral 48 denotes a resistor. One terminal of the resistor 48 is connected between the relay coil 401 and the capacitor 46, and the other terminal of the resistor 48 is connected between the B contact of the relay 400 and the motor 13. .

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

First, the switch 37 is operated to bring the movable contacts 371 and 372 into contact with the positive contact A1 and the negative contact B2, respectively. Then, a current flows momentarily from the capacitor 46 to the relay coil 401, and the relay coil 401 is excited, and accordingly, the relay 400 switches from the A contact to the B contact. As a result, the current from the battery 31 flows in the direction of the solid arrow from the relay 400 to the motor 13 to the PTC element 38, so that the motor 13 rotates (forward rotation). On the other hand, a part of the current in the direction indicated by the solid arrow flows from the resistor 48 to the relay coil 401, so that the contact state of the relay 400 with the contact B is maintained. By the rotational force of the motor 13, the mirror assembly 7 is rotated from the use position to the storage position, for example, as described above. And
When the mirror assembly 7 reaches the storage position, which is a predetermined stop position, the stopper operates, that is, the moving-side ball 12 hits the step 61 of the fixed-side arc-shaped groove 6, and the mirror assembly 7 is moved to the predetermined position. It is physically and forcibly stopped at the storage position, which is the stop position. At this time,
An overload is applied to the motor 13 and an overcurrent flows in the electric circuit. Due to this overcurrent, the internal temperature of the PTC element 38 rises, and when the temperature reaches a certain temperature range, the internal resistance of the PTC element 38 sharply increases, and the PTC element 38 performs a switching operation. Then, the power supply to the relay coil 401 is cut off, the relay 400 self-returns, switches from the B contact to the A contact, and the power supply to the motor 13 is cut off. As a result, the rotation (drive) of the motor 13 stops, and the mirror assembly 7 stops completely at the storage position. Therefore, the operation of the switch 37 is stopped, and the movable contacts 371 and 372 are automatically returned to the middle contacts C1 and C2.

Next, the switch 37 is operated to bring the movable contacts 371 and 372 into contact with the negative contact B1 and the positive contact A2, respectively. Then, a current flows momentarily from the PTC element 38 to the capacitor 46 via the relay coil 401, and the relay coil 401 is excited, whereby the relay 400 switches from the A contact to the B contact. As a result, the current from the battery 31 flows from the PTC element 38 to the motor 13 to the relay 400 in the direction indicated by the one-dot chain line, so that the motor 13 rotates (reversely rotates). On the other hand, part of the current in the direction of the dashed-dotted arrow flows from the relay coil 401 to the resistor 48, so that the contact state of the relay 400 with the B contact is self-held. By the rotational force of the motor 13, as described above, the mirror assembly 7 is rotated, for example, from the storage position to the use position. Then, when the mirror assembly 7 reaches the use position, which is a predetermined stop position, the stopper operates, that is, the moving-side ball 12 hits the step 60 of the fixed-side arc-shaped groove 6, and the mirror assembly 7 It is physically and forcibly stopped at a use position which is a predetermined stop position. At this time, an overload is applied to the motor 13, and an overcurrent flows in the electric circuit. Due to this overcurrent,
When the internal temperature of the PTC element 38 rises and reaches a certain temperature range,
The internal resistance of the PTC element 38 rapidly increases, and this PTC element 38
Performs a switching operation. Then, the relay coil
The power supply to 401 is cut off, the relay 400 self-returns, switches from the B contact to the A contact, and the power supply to the motor 13 is cut off. As a result, the rotation (drive) of the motor 13 stops, and the mirror assembly 7 stops completely at the use position. Therefore, the operation of the switch 37 is stopped, and the movable contacts 371 and 372 are automatically returned to the middle contacts C1 and C2.

As described above, the switch circuit according to the present invention in this embodiment is a PTC element 3 whose resistance value rapidly increases with temperature.
Since the switching operation is performed at 8, the number of circuit components can be reduced as compared with the case where switching is performed by a current detection element or the like. In addition, since the switching operation described above is performed instantaneously, burning of the motor 13 can be reliably prevented.

In addition, the switch circuit of the present invention in the above-described embodiment includes a mirror assembly 7 as a moving body,
Since the drive of the motor 13 is stopped after being physically and forcibly stopped at 0,61, there is no backlash in the gear group of the reduction mechanism 24 as the drive force transmission mechanism. As a result, the predetermined stop position without the mirror assembly 7
That is, it can be stopped at the use position or the storage position. Moreover, if the rotating mirror assembly 7 is physically and forcibly stopped for any reason at a position other than the predetermined stop position, the mirror assembly 7 is moved to that position by the above-described switch circuit of the present invention. The motor 13 is stopped when 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 or the like for preventing burnout of the vehicle. As a result, it is sufficient if 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 rolling in the arc-shaped groove 6. Therefore,
The motor 13 and the speed reduction mechanism 24 can be reduced in size and capacity. Further, the clutch torque of the buffering clutch mechanism 15 can be increased separately from the torque of the motor 13, so that the mirror assembly 7 can be held without play, and as a result, the image reflected on the mirror 11 is blurred. There is no danger.

Moreover, since the PTC element 38 is connected to the relay circuit 40 that cuts off the power supply to the PTC element 38 in conjunction with the switching operation of the PTC element 38, the relay circuit 40 is switched when the PTC element 38 performs the switching operation. Turn off the PTC element 38
Since the power supply to the PTC element 38 can be cut off, the durability load of the PTC element 38 can be reduced.

In the above embodiment, the steps 60 and 61 of the arc-shaped groove 6 and the ball 12 are used as the stoppers, but other techniques may be used.

Further, in the above-described embodiment, the electric retractable door mirror for a vehicle has been described. However, it can be used as a switch circuit of another driving device.

Further, instead of the switch 37 in the above embodiment,
An operation holding type switch may be used.

[Effects of the Invention] As is apparent from the above description, the switch circuit in the drive device of the present invention operates the relay contact of the relay circuit by the switching operation of the PTC element to cut off the power supply to the motor. As compared with the switch circuit of the above, the number of circuit components can be reduced, and the durability load of the PTC element can be reduced.

[Brief description of the drawings]

1 shows an embodiment of a switch circuit in a driving device according to the present invention in the accompanying drawings, FIG. 1 is an electric circuit diagram of the switch circuit of the present invention, and FIGS. 2 to 6 show an automobile equipped with the switch circuit of the present invention. 2 is a partially cutaway plan view, FIG. 3 is a cross-sectional view of an assembled state of a motor, a driving force transmission mechanism and a moving body, FIG. 4 is an exploded perspective view of the same, and FIG. 5 is a view taken in the direction of the arrow V in FIG. 4, and FIG. 6 is a development view taken along the line VI-VI in FIG. 1 ... Mirror base, 2 ... Shaft holder, 3 ...
Shaft, 6: arc-shaped groove, 7: mirror assembly (moving body), 8: unit bracket, 12: ball (stopper), 13: motor, 15: clutch mechanism, 24
…… Deceleration mechanism (driving force transmission mechanism), 31 …… Battery (power supply), 37… Switch, 38… PTC element, 60 and 6
1 ... Step (stopper).

Claims (1)

(57) [Scope of request for utility model registration] A power supply, a motor connected to the power supply via a switch, a moving body linked to the motor via a driving force transmitting mechanism, and moving by driving the motor, and moving the moving body to a predetermined position. In a driving device having a stopper for stopping, the temperature rises due to an overcurrent generated when the moving body is physically stopped due to the stopper or any cause and the motor is overloaded. PTC that performs switching operation by rapidly increasing the resistance value in a certain temperature range
An element, a PTC element connected in series between the switch and the motor, and a relay coil of a relay circuit that is demagnetized by a switching operation of the PTC element, which is connected in series to the PTC element; And a relay coil of a relay circuit connected in parallel with the motor; and the motor and the PTC by demagnetizing the relay coil.
A relay contact of a relay circuit that cuts off current to the element, the relay contact being connected in parallel with the relay coil, and a relay contact of a relay circuit connected in series with the motor and the PTC element; A starting capacitor for starting and exciting the relay coil, the starting capacitor being connected in series with the relay coil and the PTC element, and being connected in parallel with the relay contact and the motor; and A relay self-holding resistor for maintaining the excitation state of the relay, connected in series with the relay contact, the relay coil, and the PTC element, and connected in parallel with the motor and the starting capacitor. A switch circuit in a driving device, comprising: a holding resistor;