JPH04241810A - Motor-driven reclining seat - Google Patents

Abstract

PURPOSE:To prevent the overheat of a driving motor of a motor-driven reclining seat. CONSTITUTION:The reclining seat is provided with a current detecting circuit 14 for monitoring a driving current of a motor 17, a current control means 11 and a holding means 12. When the back rest part reaches the limit of a movable range, an overcurrent flowing to the motor 17 is detected, and the current control means 11 cuts off the driving current. The holding means 12 holds a control state of the current control means 11 until a switch input to the opposite direction is executed, therefore, even if the switch to said direction is depressed, electric conduction is not executed to the motor 17 and an overload is prevented.

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 that prevents overloading of a drive motor.

0002

2. Description of the Related Art Among reclining seats in which the inclination angle of the backrest of the seat can be adjusted, there is an electric type in which the adjustment operation is performed by a motor. These electric reclining seats are configured so that the seatback can be tilted to a desired angle by rotating the motor of the electric reclining mechanism in the forward or reverse direction by operating a switch by the seated person.

0003

A 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 approximately vertical. In an electric reclining seat, when the backrest part is raised or reclined by operating a switch and it touches the stopper at the limit of its movable range, if the switch is continued to be pressed, the drive motor locks. The current is turned on and a large current flows. As a result, the motor may overheat, resulting in shortened lifespan, breakage of the coil, or other malfunctions, and the increased temperature may pose safety problems.

[0004]Therefore, in order to provide an electric reclining seat that prevents the motor from being overloaded, eliminates the risk of failure of the motor, and improves durability and safety, there are technical issues to be solved. The present invention aims to solve this problem.

[0005]

[Means for Solving the Problems] This invention is proposed to achieve the above object, and the reclining seat has a built-in motor, and the inclination angle of the backrest can be adjusted within a certain range by the motor. The electric reclining seat includes a current detection circuit that detects the drive current of the motor, and a current control means that controls the motor drive circuit based on the detected value of the current detection circuit, and limits the drive current when an overcurrent is detected. In addition, it is an object of the present invention to provide an electric reclining seat characterized in that a holding means is provided for maintaining the restriction until a reversal command is input to the motor.

[0006]

[Operation] When one of the two switches provided for the reclining operation, one for standing up and one for folding down, 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 its movable range and comes into contact with the stopper, preventing rotation. As a result, the drive motor is forcibly stopped from rotating, and a large current flows through the coil of the motor. The current control means detects that the motor is in a locked state via the current detection circuit, and limits or cuts off the drive current of the motor.

In the current control means, the holding means holds the current limit to the motor until a reversal command is input from the other switch, so even if the same switch is continued to be pressed, the motor will not be energized and will remain in the locked state. The motor will not be overloaded.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an electric reclining seat 1 with a built-in electric massage mechanism, and a backrest portion 2 is configured to be able to rise and fall freely 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 whose one end is pivotally attached to the lower surface of the seating portion 3 as shown in the figure. The other end of the stopper member 4 is pivotally connected to a lever 5 fixed to the backrest 2, and as the backrest 2 is tilted, the stopper member 4 is moved.
expands and contracts. At the limit of the movable range of the stopper member 4, the backrest portion 2 is prevented from tilting and stops, and its stopping positions are the upright state and the horizontal state shown in the figure.

The backrest portion 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 portion 6. The operation panel 7 is provided with a power switch, a selection switch for various massage programs, etc., as well as a backrest up switch 8 and a down switch 9.

FIG. 2 is a circuit block diagram of the drive mechanism.
10 is a CPU, 11 is a current control means, and 12 is a holding means. The up switch 8 and down switch 9 are CP
Connected to U10. When the signal is input from the lift switch 8, the current control means 11 turns on the motor drive circuit 13 to drive the motor 17, and the backrest part 2
stand up. The motor 17 continues to rotate while the lift switch 8 is pressed, and when the backrest 2 reaches a desired angle, the lift switch 8 is turned off and the backrest 2 stops at that angle.

On the other hand, when the lowering switch 9 is turned on, the current control means 11 of the CPU 10 is activated by the relay drive circuit 15.
energizes to drive the relay circuit 16, and after switching the polarity of the motor 17, the motor drive circuit 13 is activated. Therefore, the motor 17 rotates in the reverse direction, and the backrest portion 2 is tilted toward the sleeping direction. If you keep pressing switches 8 and 9 for a certain period of time in either direction of standing up or folding down, the backrest part 2
reaches the limit of its movable range and is prevented from rotating by the aforementioned stopper member 4. At this time, the motor 17 is forcibly stopped from rotating, and an overcurrent flows through the motor 17. The CPU 10 detects an overcurrent via a current detection circuit 14 using a current transformer, and stops the operation of the motor drive circuit 13 to cut off the power supply to the motor 17.

FIG. 3 is a timing chart when the lift switch 8 is pressed, and the motor 17 starts 150 ms after the switch is operated, and when the lift switch 8 is turned off, the motor 17 stops instantly. FIG. 4 shows a timing chart when the lift switch 8 is continued to be pressed until the backrest portion 2 stands up to the upright position and is prevented from rotating by the stopper member 4. At the time point A, the backrest portion 2 reaches the limit of its movable range, and the motor 17 in the energized state
is prevented from rotating and an overcurrent flows. The current control means 11 controls the motor 17 when this state continues for 150ms.
Since the holding means 12 of the CPU 10 maintains this state, the motor 17 in the locked state will not be driven even if the lift switch 8 is kept pressed or pressed again.
No damage caused by overcurrent.

FIG. 5 is a timing chart when the lowering switch 9 is turned on. At the same time as the lowering switch 9 is turned on, the relay drive circuit 15 operates to switch the power supply connection polarity of the motor 17.
After 50ms, the motor drive circuit 13 is turned on and the motor 1 is turned on.
7, and fold down the backrest part 2. When the lowering switch 9 is turned off when the backrest portion 2 reaches a desired angle, the motor 17 is first stopped, and after 1 sec, the relay drive circuit 15 is stopped energized, and the relay circuit 16 is connected to normal rotation. Return.

FIG. 6 shows the case where the lowering switch 9 is kept pressed, and at time B, the backrest 2 reaches a horizontal state and is prevented from rotating by the stopper member 4, causing an overcurrent to flow to the motor 17. Then, after 150ms, motor drive circuit 1
3 is turned off, and after 1 sec, the relay drive circuit 15 is turned off. The holding means 12 maintains the cutoff state of the drive current to the motor 17 shown in FIGS. 4 and 6 until a switch input in the opposite direction is made, but the minimum holding time is 1 sec.
Set the above settings. That is, when the backrest portion 2 is lowered to the locked state and the drive current of the motor 17 is stopped,
Even if the lift switch 8 is turned on immediately, the motor 17 is not energized at the same time, and the motor 17 is reversed after a predetermined holding time has elapsed. Therefore, it is possible to prevent starting current from being applied to the motor 17, which is in the locked state and an overcurrent flows therethrough, without any interval, thereby causing an overload. Also, even if the ascending switch 8 and descending switch 9 are repeatedly turned on and off alternately, the motor 17
does not reverse continuously, but reverses at predetermined intervals, so an excessive starting current will not flow.

In this way, overload on the motor 17 is reduced as much as possible to prevent overheating. Note that this invention can be modified in various ways without departing from the spirit of the invention, and it goes without saying that this invention extends to such modifications.

[0016]

Effects of the Invention As described in detail in the above-mentioned embodiment, this invention detects the limit of the movable range of the backrest using the motor drive current and instantly shuts off the drive current. It is possible to prevent failures caused by
Not only can durability be improved, but the dangers caused by heat generation can be eliminated and safety can be ensured. Furthermore, compared to mechanical position detection means such as limit switches, the invention does not require an increase in the number of parts, and has advantages in terms of reliability and cost.

[Brief explanation of the drawing]

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

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

FIG. 3 is a timing chart when operating the lift switch.

FIG. 4 is a timing chart when the rise switch is held down.

FIG. 5 is a timing chart when operating the lowering switch.

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

[Explanation of symbols]

1 Electric reclining seat 2 Backrest part 4 Stopper member 8 Rise switch 9 Lower switch 10 CPU 11 Current control means 12 Holding means 14 Current detection circuit 17 Motor

Claims (1)

[Claims] 1. In an electric reclining seat in which a motor is built into the reclining seat and the inclination angle of a backrest portion can be adjusted within a certain range by the motor, a current detection circuit for detecting a driving current of the motor; Current control means for controlling a motor drive circuit based on a detection value of the current detection circuit, and holding means for limiting the drive current when an overcurrent is detected and maintaining the limitation until a reversal command is input to the motor. An electric reclining seat characterized by the provision of.