JP2623536B2 - Power window drive - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a power window drive device that opens and closes a door glass by driving a DC motor.

(Prior art) Conventionally, in a power window device that opens and closes a door glass by forward and reverse rotation of a DC motor, the door glass is opened and closed by forward and reverse rotation of a DC motor through an opening and closing mechanism known as a window regulator. This window regulator incorporates a balancing spring to equalize the driving torque when opening and closing the door glass (see the complete book of Automotive Engineering, Chapter 1).
Volume 13 "Passenger car body" published on April 1980, see Sankaido page 134).

That is, when the door glass is lowered (opened), the driving torque can be reduced by receiving the weight of the door glass. On the other hand, when the door glass is raised (closed), the driving torque is reduced by the weight of the door glass. Only the driving torque increases,
In order to equalize the driving torque at the time of raising and lowering, the driving torque is mechanically increased by winding the balancing spring when the door glass is lowered, while the winding spring is wound by unwinding the winding spring when the door glass is raised. The output torque is generated to mechanically increase the driving torque, and the function of the balancing spring suppresses fluctuations in the driving torque and speed at the time of ascending and descending due to forward and reverse rotation of the motor.

(Problems to be Solved by the Invention) However, in the power window device in which such a conventional balancing spring is used to equalize the driving torque and the speed at the time of ascending and descending, the driving mechanism has a balancing spring. And the winding and unwinding mechanism must be provided, which complicates and enlarges the configuration of the device.The absorption torque obtained by winding the balancing spring and the torque generated by unwinding the spring are the same as when the spring starts winding. Since it differs at the end of winding, there is a problem that the driving torque and speed at the time of ascending and descending cannot always be equalized.

(Means for Solving the Problems) The present invention has been made in view of such a conventional problem. Even if the load torque at the time of ascending and that at the time of descent are different, the DC motor can be used without using a balancing spring. An object of the present invention is to provide a power window driving device capable of equalizing a door opening / closing speed only by forward / reverse rotation.

In order to achieve this object, according to the present invention, in a power window drive device for opening and closing a door glass by a DC motor, a first brush that slides a commutator on the DC motor and a first brush that faces the first brush. A second brush having a flexible portion bent inward in the middle of the brush supporting member at a portion to be rotated, and when rotating in a direction to raise the door glass, the second brush is rotated in a rotational direction of the commutator. Receives the force of the sliding resistance, the flexible portion is pulled out by the force of the sliding contact resistance, and the second brush moves to a position shifted from the initial position by a predetermined angle.

(Operation) According to such a configuration of the present invention, when the door glass is lowered, the brush is in a proper current distribution position with respect to the commutator, so that a specified torque is generated. On the other hand, when the door glass rises, the brush receives the force due to the sliding resistance in the rotating direction of the commutator, and the flexible portion bent inward is pulled out by the force F due to the sliding resistance, and the sliding position of the second brush is brought into contact. Moves from the proper current distribution position to a position shifted by a predetermined angle θ, the drive torque increases by an increase in the armature current due to a decrease in the armature internal resistance by the movement of the brush position. In this way, the DC motor itself can change the drive torque when the door glass is lowered and when the door glass is raised by moving the brush position when the DC motor rotates in the forward and reverse directions.

(Example) Hereinafter, an example of the present invention will be described. FIG. 1 is an explanatory view showing a brush sliding contact structure with respect to a commutator 10 of an 8-pole DC motor according to an embodiment of the present invention.

In the embodiment shown in FIG. 1, the second brush 6 which is disposed so as to face the first brush 5 with the center line 11 therebetween,
When the door glass rises, the commutator 10 is automatically moved to a position shifted by a predetermined angle θ from a proper current distribution position facing the center line 11 due to sliding resistance caused by rotation of the commutator 10.

That is, the brush support member 15 supporting the second brush 6
Has a flexible portion 16 which is bent inward on the way, and when the commutator 10 rotates when the door glass descends as indicated by an arrow in FIG. 1, the second brush 6 is driven by the rotation of the commutator 10. Even if a force due to the sliding resistance is received, as shown in the figure, it is maintained at a proper current distribution position facing the first brush 5 on the center line 11. However, when the commutator 10 is rotated in the reverse direction indicated by an arrow as shown in FIG. 2 to raise the door glass, the brush 6 receives the force F due to the sliding resistance in the rotation direction of the commutator 10, and the brush supporting member The 15 flexible portions 16 are pulled out by the force F due to the sliding resistance, and the sliding position of the second brush 6 is shifted to the center line 11.
From the appropriate current distribution position, the armature current increases due to the decrease in the armature internal resistance due to the movement of the second brush 6, thereby increasing the driving torque when the glass is raised. Can be done.

In switching the rotation direction of the commutator, a battery serving as a DC power supply and a changeover switch for switching between raising and lowering the power window are used. The changeover switches are interlocking changeover switches, and are respectively a lower changeover position and a higher changeover position. The (+) side of the battery is connected to the down switching position of the changeover switch, and the (-) side of the battery is connected to the up switching position. The (−) side of the battery is connected to the lower switching position of the changeover switch, and the (+) side of the battery is connected to the upper switching position. That is, the changeover switch has a function as a reversing switch unit that switches and outputs the polarity of the power supply of the battery. The DC motor is connected to the output side of the changeover switch.

As described above, when the changeover switch is switched to the raised position, power is supplied by the second brush 6 at a position shifted by a predetermined angle θ from the first brush 5 and the appropriate current distribution position. Only the armature internal resistance decreases, and the armature current Ia increases accordingly.

Taking a shunt DC motor as an example, there is a relationship of T = KφIa (where K is a proportional constant and φ is a magnetic field flux) between the armature current Ia and the generated torque T. As the current Ia increases, the driving torque T increases.

Therefore, even if a balancing spring is not incorporated in the door glass opening / closing drive mechanism in the power window, when the door glass is lowered, the DC motor originally has an appropriate current distribution by the first brush 5 and the second brush 6. When the door glass is raised, the armature is fed by the second brush 6 and the first brush 5 at a position where the second brush 6 is shifted by a predetermined angle θ when the door glass is raised. By reducing the internal resistance and increasing the armature current, the drive torque of the DC motor can be increased when the door glass rises as compared to when the door glass falls. For this reason, when the DC motor itself rises and descends, the driving torque is different, so that when the door glass rises receiving the weight of the door glass as a positive load, and when the door glass descends receiving the weight of the door glass as a negative load, The DC motor generates a different drive torque according to each drive load, and the opening / closing drive of the door glass can be kept substantially uniform without a balancing spring.

Further, according to the above embodiment, as shown in FIG.
The brush 6 itself moves to a position shifted by a predetermined angle θ by the rotation of the commutator 10 when the door glass is raised, so that the output of the changeover switch is directly connected to the first brush 5 and the second brush 6 only. In addition, a sufficient driving torque can be increased when the door glass is raised, as compared with when the door glass is lowered. As a conventional method, there is known a configuration in which a third brush is separately disposed at a position where the second brush 6 is shifted by a predetermined angle θ, but in this configuration, the rotation direction of the DC motor is changed. In the case of switching, a switching circuit using diodes D1, D2 and the like is required, but in the above embodiment, this is not necessary.

(Effects of the Invention) As described above, according to the present invention, in a power window device that opens and closes a door glass by a DC motor, the DC motor is provided with a first brush and a brush supporting member that are in sliding contact with a commutator. A second brush having a flexible portion bent inward in the middle thereof, and when rotating in a direction to raise the door glass, the flexible portion is pulled out by a force due to sliding resistance and the second brush is Is moved to a position shifted by a predetermined angle from the initial position, so that the drive torque when the door glass is raised can be increased by the DC motor itself with respect to the drive torque when the door glass is lowered. Since there is no need to provide a balancing spring for absorbing different torques when the glass is raised and lowered, the mechanism structure can be greatly simplified, The motor itself can change the driving torque according to the ascending rotation and descending rotation, so there is no need for a special external circuit to vary the driving torque of the DC motor,
Furthermore, the necessary brush displacement can be obtained with a simple configuration, and a power window driving device that is inexpensive can be realized.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a brush structure for a commutator of a DC motor used in an embodiment of the present invention, and FIG. 2 is an explanatory view showing a brush moving state at the time of upward rotation in the brush structure of FIG. . 5: first brush 6: second brush 10: commutator 11: center line 15: brush support member 16: flexible part

Claims (1)

(57) [Claims] 1. A power window driving device for driving a door glass to open and close by a DC motor, wherein a first brush slidingly contacts a commutator with the DC motor and a brush support member is provided at a portion opposed to the first brush. A second brush having a flexible portion bent inwardly is provided, and when rotating in a direction to raise the door glass, the second brush receives a force due to sliding resistance in a rotating direction of the commutator. The power window driving device, wherein the flexible portion is pulled out by the force of the sliding resistance and the second brush moves to a position shifted from the initial position by a predetermined angle.