JP2984768B2 - Electric reclining seat - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric reclining seat, and more particularly to an electric reclining seat for preventing an overload on a driving motor.

[0002]

2. Description of the Related Art There is an electric reclining seat in which a tilting angle of a backrest of a seat can be adjusted by an electric motor. These electric reclining seats are configured so that the backrest can be tilted to a desired angle by rotating the motor of the electric reclining mechanism forward or backward by a switch operation of a seated person.

[0003]

The reclining seat is provided with a mechanical stopper in order to restrict the movable range of the backrest to a certain angle, for example, from horizontal to substantially vertical. In the electric reclining seat, when the backrest is raised or turned down by the switch operation and abuts on the stopper at the limit of the movable range, if the switch is further kept pressed, the drive motor is locked. It is energized as it is and a large current flows. As a result, the motor overheats to cause a failure such as a shortened life or a broken coil, or a safety problem due to a rise in temperature.

Therefore, there is a technical problem to be solved in order to prevent an overload of a motor, to eliminate the possibility of failure of the motor, and to provide an electric reclining seat with improved durability and safety. The present invention aims to solve the problem.

[0005]

SUMMARY OF THE INVENTION The present invention has been proposed to achieve the above-mentioned object. A motor is built in a reclining seat, and the inclination angle of a backrest can be adjusted within a certain range by the motor. And an electric reclining seat including a current detection circuit for detecting a drive current of the motor , and current control means for controlling the motor drive circuit based on a detection value of the current detection circuit.
When the overcurrent is detected by the current detection circuit, the motor
Limiting the drive current, there is provided St. an electric reclining seat provided with retention means for the limited subset are maintained until inversion command to the motor is input.

[0006]

When one of the two switches provided for the reclining operation, one for standing up and one for turning over, is turned on, the drive motor is energized and the backrest rotates in the direction indicated by the switch. When the switch is turned off, the drive motor stops, and the backrest stops rotating. When the switch is kept on, the backrest tilts to the limit of the movable range and abuts against the stopper, thereby preventing rotation. As a result, the drive motor is forcibly prevented from rotating, and a large current flows through the coil of the motor. The current control means detects that the motor has been locked through the current detection circuit, and limits or interrupts the drive current of the motor.

The current control means holds the current limit to the motor by the holding means until the reversal command is input from the other switch. Therefore, even if the same switch is further pressed, the motor is not energized, and the locked state is maintained. There is no overload on the motor.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 shows an electric reclining seat 1 having a built-in electric massage mechanism, and a backrest portion 2 is configured to be able to stand up and down between an upright position shown by a solid line and a horizontal position shown by a chain line. This movable range is defined, for example, by a stopper member 4 such as a cylinder having one end pivotally connected to the lower surface of the seat 3 as shown in FIG. The other end of the stopper member 4 is pivotally connected to a lever 5 fixed to the backrest 2, and the stopper member 4 is tilted with the backrest 2.
Expands and contracts. At the limit of the movable range of the stopper member 4, the backrest 2 is stopped by being prevented from tilting, and the stop position is in the upright state and the horizontal state shown in FIG.

The backrest 2 is driven by a drive mechanism (not shown) including a motor and a worm gear, and the drive mechanism is operated by an operation plate 7 provided on the upper surface of the armrest 6. The operation plate 7 is provided with an up switch 8 and a down switch 9 for the backrest, in addition to a power switch and a selection switch for various massage programs.

FIG. 2 is a circuit block diagram of the driving mechanism.
Reference numeral 10 denotes a CPU, 11 denotes a current control unit, and 12 denotes a holding unit. The up switch 8 and the down switch 9 are CP
It is connected to U10. When a signal is input from the up switch 8, the current control means 11 turns on the motor drive circuit 13 to drive the motor 17, and the backrest 2
Erect. The motor 17 continues to rotate while the elevation switch 8 is being pressed, and when the elevation switch 8 is turned off when the backrest 2 reaches a desired angle, the backrest 2 stops at that angle.

On the other hand, when the down switch 9 is turned on, the current control means 11 of the CPU 10
5 to drive the relay circuit 16, switch the polarity of the motor 17, and then operate the motor drive circuit 13. Therefore, the motor 17 rotates in the reverse direction, and the backrest 2 is turned in the sleeping direction. When the switches 8 and 9 are continuously pressed for a certain period of time in either the upright or inverted directions, the backrest 2 reaches the limit of the movable range, and the stopper member 4 described above.
Is prevented from rotating. At this time, the rotation of the motor 17 is forcibly prevented, and an overcurrent flows through the motor 17. The CPU 10 detects an overcurrent through the current detection circuit 14 using the current transformer, stops the operation of the motor drive circuit 13 and cuts off the power supply to the motor 17.

FIG. 3 is a timing chart when the up switch 8 is pressed. The motor 17 starts 150 ms after the switch is operated, and when the up switch 8 is turned off, the motor 17 stops immediately. FIG. 4 shows a timing chart in the case where the lifting switch 8 is kept pressed until the backrest 2 stands upright and is prevented from rotating by the stopper member 4. At time A, the backrest 2 reaches the limit of the movable range, and the motor 17 in the energized state is prevented from rotating, and an overcurrent flows. Current control means 1
1 stops the driving of the motor 17 when this state continues for 150 ms, and the holding means 12 of the CPU 10 maintains this state. It is not driven and is not damaged by overcurrent.

FIG. 5 is a timing chart when the down switch 9 is turned on. At the same time as the down switch 9 is turned on, the relay drive circuit 15 is operated to switch the power supply connection polarity of the motor 17 to change the polarity.
After 50 ms, the motor drive circuit 13 is turned on and the motor 17 is turned on.
And the backrest 2 is turned over. The backrest 2
If the lowering switch 9 is turned off when the angle reaches a desired angle, the motor 17 is first stopped, and after one second, the power supply to the relay drive circuit 15 is stopped, and the relay circuit 16 returns to the normal rotation connection.

FIG. 6 shows a case in which the lowering switch 9 is kept depressed. At the time point B, the backrest 2 reaches a horizontal state, the rotation of the stopper member 4 is prevented, and an overcurrent flows through the motor 17. Then, after 150 ms, the motor drive circuit 13
Is turned off, and after one second, the relay drive circuit 15 is turned off. The holding means 12 holds the drive current cutoff state to the motor 17 shown in FIGS. 4 and 6 until a switch input is made in the opposite direction, and the minimum holding time is set to 1 second or more. That is, if the drive current of the motor 17 is stopped by lowering the backrest 2 to the locked state, the motor 17 is not energized at the same time even if the raising switch 8 is immediately turned on, and after a predetermined holding time has elapsed, Reverse. Therefore, it is possible to prevent the starting current from flowing to the motor 17 in which the overcurrent has flown in the locked state without an interval, thereby preventing the motor 17 from being overloaded. Even if the up switch 8 and the down switch 9 are alternately turned on / off alternately, the motor 17 does not continuously reverse, but reverses at a predetermined interval, so that an excessive starting current does not flow.

Thus, the overload on the motor 17 is reduced as much as possible to prevent overheating. The present invention can be variously modified without departing from the spirit of the present invention, and it goes without saying that the present invention extends to the modified ones.

[0016]

According to the present invention, as described in detail in the above-described embodiment, the erecting and turning-up devices provided for the reclining operation are provided.
When one of the two switches is turned on, the drive motor
The backrest rotates in the direction indicated by the switch.
You. When the switch is turned off, the drive motor stops and the back
The part stops rotating. Hold the switch on
And the backrest tilts to the limit of the movable range and stops.
And the rotation is prevented. This allows the drive motor
Is forcibly stopped from rotating and the motor coil has large current
Flows. The current control means is connected to the motor via the current detection circuit.
Detects that the motor is locked, and drives the motor.
Limit or cut off current. Thus, the current detection circuit
Motor drive current due to the overcurrent when the overcurrent is detected by the path
When the current control means is limited,
A reverse command is input from the other switch to limit the current to the motor.
Press and hold the same switch again to hold until pressed
The motor is not energized even if
There is no load. Therefore, according to the present invention, it is possible to prevent a reduction in life due to heat generation of the motor and a failure due to disconnection beforehand, to improve the durability, and to eliminate the danger due to heat generation and secure safety. Further, the present invention does not increase the number of parts as compared with mechanical position detecting means such as a limit switch, and has advantages in reliability and cost.

[Brief description of the drawings]

FIG. 1 is a side view of an electric reclining seat.

FIG. 2 is a circuit block diagram of a driving mechanism.

FIG. 3 is a timing chart when an up switch is operated.

FIG. 4 is a timing chart when the up switch is kept pressed.

FIG. 5 is a timing chart when a down switch is operated.

FIG. 6 is a timing chart when the down switch is kept pressed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric reclining seat 2 Backrest part 4 Stopper member 8 Up switch 9 Down switch 10 CPU 11 Current control means 12 Holding means 14 Current detection circuit 17 Motor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-8033 (JP, A) JP-A-60-100913 (JP, A) JP-A-61-181409 (JP, A) JP-A-1- 101923 (JP, A) Japanese Utility Model Showa 61-101493 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) A47C 1/024

Claims (1)

(57) [Claims] A motor is built in a reclining seat, a tilt angle of a backrest can be adjusted within a certain range by the motor , and a current detecting circuit for detecting a driving current of the motor; Electric motor with current control means for controlling the motor drive circuit based on the detected value
In the lining sheet, when an overcurrent is detected by the current detection circuit, the motor drive current due to the overcurrent is limited.
When an electric reclining seat, wherein said that the limit provided retaining means that will be Wei <br/> lifting to the reversing command to the motor is input.