JPH06328940A - Door opening and closing device of automobile - Google Patents

Abstract

PURPOSE:To open and close a door in the state suitable for several conditions by giving assist force at the time of opening and closing the door. CONSTITUTION:Opening and closing operational physical force of a door 1 is detected through a rotating sensor 71. In accordance with the opening and closing operational physical force of the door 1, an assist force giving member is driven by a motor 6 and assist force to assist opening and closing of the door 1 is given. When the opening and closing operational physical force is large, the assist force is increased, and when the opening and closing operational physical force is small, the assist force is decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle door opening / closing device for assisting opening / closing of a door.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Utility Model Laid-Open No. 62-7518
As described in Japanese Unexamined Patent Publication (Kokai) No. 0, a door handle is installed at one end on the open side of the door, and a door lock device that interlocks with the door handle and engages with and disengages from a striker placed on the opening edge of the vehicle body is installed. It is arranged at the front end and the rear end, is attached to the vehicle body through a swing arm in the approximate center of the door, and the open-side upper end or lower end of the door cooperates with the swing arm to form a parallelogram. In a swing door opening / closing mechanism attached to a vehicle body via a joint link member, between the other end of the door on the side opposite to the opening side of the door and the vehicle body, the unlocking movement of the door lock device is performed. It is known that a door pushing mechanism that interlocks to push the door outward and returns after pushing is provided.

[0003]

However, in such a structure, since the door is automatically opened and closed, it is necessary to always apply a constant opening and closing force to the door, and it is necessary to change it according to the conditions. I couldn't.

It is an object of the present invention to provide a door opening / closing device for an automobile, which is capable of opening / closing the door in a state satisfying various conditions by applying an assisting force when opening / closing the door. Is.

[0005]

According to the present invention, there is provided a door opening / closing device for an automobile, in which an actuator is attached to the inside or the outside of the door, the operating state of an operating portion provided on the door is detected, and the actuator assists the opening and closing of the door. Is assumed.

According to the first aspect of the present invention, an operating force detecting means for detecting the opening / closing operating force of the door and an output of the operating force detecting means are provided to control the assist force by the actuator according to the opening / closing operating force of the door. And a control means.

According to a second aspect of the present invention, there is provided speed detecting means for detecting the opening / closing speed of the door, and control means for receiving the output of the speed detecting means and controlling the assisting force by the actuator according to the opening / closing speed of the door. The configuration is provided.

According to a third aspect of the invention, the door opening / closing detecting means for detecting the opening / closing position of the door, and the actuator in the direction in which the assist force increases when the door is in a predetermined position upon receiving the output of the door opening / closing detecting means. And a control means for controlling the assisting force by.

According to a fourth aspect of the present invention, an opening / closing operation detecting means for detecting whether the door is opened / closed from the door inner side or the door outer side, and an output from the door opening / closing operation detecting means are received from the door inner side. And a control means for controlling the driving force of the actuator so that the assist force changes depending on whether the opening / closing operation is performed or the opening / closing operation is performed from the door outer side.

According to a fifth aspect of the present invention, an inclination degree detecting means for detecting the inclination degree of the door, and a control means for receiving the output of the inclination degree detecting means and controlling the driving force of the actuator in accordance with the inclination degree of the automobile. Is provided.

According to a sixth aspect of the present invention, when the vehicle is in the drivable state, the drivable state detecting means for detecting whether the vehicle is in the drivable state or not, and the output of the drivable state detecting means are received. And a control means for prohibiting the operation of the actuator.

According to a seventh aspect of the present invention, an obstacle detecting means for detecting an obstacle in the opening / closing locus of the door, and an output when the obstacle detecting means outputs the obstacle and the actuator is present in the opening / closing locus of the door. And a control means for prohibiting the operation of.

According to an eighth aspect of the present invention, door position detecting means for detecting a fully open position and a fully closed position of the door, and an output from the door position detecting means, the actuator is controlled near the fully open position and the fully closed position of the door. However, a control means for reducing the door speed is provided.

[0014]

According to the invention of claim 1, the assisting force by the actuator for assisting the opening and closing of the door is controlled according to the opening and closing operation force of the door.

According to the second aspect of the present invention, the assist force by the actuator for assisting the opening and closing of the door is controlled according to the opening and closing speed of the door, and when the opening and closing speed of the door is high, the assisting force is higher than that when the opening and closing speed of the door is slow. Increase the torque.

According to the third aspect of the invention, when the door is at the predetermined position, the assist force by the actuator for assisting the opening and closing of the door is controlled in the direction in which the assist force increases, and the assist force at the predetermined position is increased. .

According to the fourth aspect of the present invention, the driving force of the actuator is controlled so that the assist force changes between the opening / closing operation from the door inner side and the opening / closing operation from the door outer side.

According to the invention of claim 5, the driving force of the actuator for assisting the opening and closing of the door is controlled according to the degree of inclination of the automobile. That is, the assist force is increased when the inclination is in the direction of increasing the operating force, and conversely, the assist force is cut when the inclination is in the direction of decreasing the operating force.

According to the sixth aspect of the present invention, when the vehicle is in a drivable state, the operation of the actuator for assisting the opening and closing of the door is prohibited and the assist force is cut.

Further, according to the invention of claim 7, when an obstacle is present in the opening / closing locus of the door, the operation of the actuator for assisting the opening / closing of the door is prohibited and the assist force is cut.

According to the eighth aspect of the invention, the actuator for assisting the opening and closing of the door is controlled near the fully open position and the fully closed position of the door, and the assist force is reduced.

[0022]

Embodiments of the present invention will now be described in detail with reference to the drawings.

In FIG. 1 and FIG. 2 showing the schematic structure, 1
Is the door of the car, the inner panel 1a and the outer panel 1
b, and is openably (rotatably) pivotally attached to the vehicle body 13 via door hinge means 2A, 2B which are vertically arranged and have a vertical rotation shaft 2a.

At a substantially intermediate position in the vertical direction of the door hinge means 2A, 2B and at a position offset from the hinge shaft 3 thereof, one end of the assist force applying member 4 is pivotally attached to the vehicle body 13. . Specifically, one end of the assisting force imparting member 4 is pivotally attached to a bracket 5 fixed to the vehicle body 13.

Reference numeral 6 denotes a motor which is an actuator, which is arranged inside the door 1 (between the inner panel 1a and the outer panel 1b) and serves as a drive source for giving an assisting force for assisting the opening and closing of the door 1. There is. Also, the motor 6
Is a free state when the current is cut off.

A window glass 7 is constructed so that it can be moved up and down by a window regulator 8.
9 is a door lock assembly, 10 is a door trim, 11
Is a floor panel, and 12 is a side sill.

Further, as shown in detail in FIGS. 3 to 5, the motor 6 has a gear 21 fixed to the motor shaft 6a, and the gear 21 is provided with the assist force applying member 4 via the motion converting means 22. Is linked to the other end of the.

Specifically, the reduction gear 23 meshes with the gear 21, the reduction gear 23 is fixed to one end of a worm gear shaft 24 extending in parallel with the assist force applying member 4, and the worm gear shaft 24 is connected to the motor. It is constituted so as to be rotated at a reduced speed by 6.

Reference numeral 25 is a slider, which is an assisting force applying member 4
A cylindrical portion 25c having a connecting portion 25a that is pin-connected to one end of the
And an engaging portion 25d extending from the tubular portion 25c to the side opposite to the connecting portion 25a.

Reference numeral 26 denotes a hollow motor case, which is connected to one end of the tubular portion 26b and a square tubular tubular portion 26b having an opening 26a through which the other end of the assisting force applying member 4 projects. And a connecting portion 26c extending downward.
6c is connected to the flange portion 6b of the motor 6. Then, in this combined state, the motor case 2
Inside of 6, the assist force imparting member 4 and the worm gear shaft 2 are provided.
4, the reduction gear 23, the slider 25, etc. are accommodated. Further, on the inner wall of the motor case 26,
A guide groove 26d with which the engaging portion 25d of the slider 25 is slidably engaged is formed.

Then, the assist force applying member 4, the worm gear shaft 24, the reduction gear 23, the slider 25, etc. constitute a motion converting means 22 for converting the rotational operation of the motor 6 into the assist force applying motion of the assist force applying member 4. ing.

Further, as shown in FIGS. 6 to 11, the door 1
On the inner handle 36 and the outer handle 37, which are opening / closing operation parts of the above, operation switches 39 and 41 for controlling the operation and stop of the motor 6 are provided.

That is, as shown in FIGS. 6 and 7, an inner handle 36 is rotatably pivotally mounted on a mounting portion 35 of the inner panel 1a, and the inner handle 36 is linked to the door lock assembly 9 by an operation. The members 43 are connected. Further, an operation switch 39 (pusher switch) is attached via a mounting bracket 38. When the inner handle 36 is rotated, the operation switch 3
Since 9 is pressed, the operation switch 39 is closed and the motor 6 is rotationally driven in a predetermined direction to generate an assist force for opening and closing the door.

On the other hand, as shown in FIG. 6, FIG. 8 and FIG. 93, the outer handle 37 includes two front and rear hinge portions 37.
A and 37B are rotatably pivotally attached to the outer panel 1b, and the mounting bracket 40 and the mounting portion 37a of the outer handle 37 near one hinge portion 37A.
An operation switch 41 (pull switch) is provided between and. Then, when the outer handle 37 is rotated, the operation switch 41 is pulled to rotationally drive the motor 6 in a predetermined direction to generate an assisting force for opening and closing the door 1. Also, the other hinge 37
In the vicinity of B, the protruding portion 37b of the outer handle 37
Are linked to the door lock assembly 9 via the operating member 42.

In addition to the switches 39 and 41, as shown in FIGS. 10 and 11, the armrest section 5 is provided.
The upper and lower door trims 10 and 1 are also provided with lower and upper operation switch means 52 and 53 for generating an assisting force for assisting the opening and closing of the door. Specifically, for example, in the case of the lower operation switch means 52 of the armrest portion 51, as shown in FIGS. 10 and 11, the door trim 1
At 0, a board portion 54 having an opening 54a in the center is attached and fixed. Through a spring 56, a washer 57, and a nut 58, a movable plate portion 55 having a projecting portion 55a having a tip screw portion slidably inserted into the opening 54a is movable in the base plate portion 54 via a spring 56, a washer 57, and a nut 58. Installed. Further, the guide shaft members 55b, ... Of the movable plate portion 55 provided corresponding to the guide hole portions 54b, ... Arranged at the four corners of the substrate portion 54 are slidably fitted. There is. Then, between the plate parts 54 and 55,
Further, operation switches 59, 59, 59, 59 for driving and controlling the motor 6 are provided in the vicinity of the respective guide shaft members 55b, ....
Is provided. The upper operation switch means 53 has the same structure as the lower operation switch means 52.

Further, reference numeral 61 is a control unit, which is a door hinge means 2A above the door 1 as shown in FIG.
A torque sensor 71 for detecting the opening / closing operation force of the door 1 and the tilting state of the vehicle, and a rotation sensor 72 for detecting the opening / closing speed and the opening / closing direction of the door 1 arranged on the door hinge means 2B below the door 1. And a position sensor 73 that is provided on the lower hinge portion of the door 1 to detect the opening / closing angle of the door 1 and to detect the fully open position and the fully closed position of the door 1; Whether or not the vehicle is in a drivable state, which is linked to the inner handle switch 74 for detecting the operation, the outer handle switch 75 for detecting the operation from the outside of the vehicle and linked to the door outer handle 37, and the speedometer (not shown). The vehicle speed sensor 76 for detecting the
The power unit 7 receives a signal from the clearance sonar 78 that detects whether or not there is an obstacle in the opening / closing locus of the power unit 7.
The motor 6 is driven via 9 to control the assist force application member 4. 80 is a battery.

As shown in FIG. 13, the power unit 79 is driven and controlled by the power relay 81, the current is cut off by the fail-safe relay 82, the drive is detected by the current sensor 83, and the assist in the opening / closing operation is performed. Force control,
The control unit 61 receives signals from the control unit 61 to perform assist force cut under certain conditions, assist force cut at abnormal times, change of rotation direction of the motor 6 during opening and closing operations, automatic stop upon detection of obstacles, etc. Bridge circuit B1
The motor drive current is controlled by the drive circuit 84 via B4 to B4. Reference numeral 85 is a main fuse, and 86 and 86 are fuses. Bridge circuit B1
The basic control of B4 to B4 is as shown in Table 1.

[0038]

[Table 1] Specifically, the assist force by the motor 6 that assists the opening and closing of the door 1 is controlled according to the opening and closing operation force of the door 1 detected by the torque sensor 71.

The door 1 detected by the rotation sensor 72 in order to prevent the operability from being deteriorated when the opening / closing operation is performed faster than the opening / closing speed of the door 1 by applying the assisting force.
The assist force of the motor 6 that assists the opening and closing of the door 1 is controlled according to the opening and closing operation speed of the. That is, the door 1
When the opening / closing speed is fast, the assisting power is increased as compared to when the opening / closing speed is slow. Then, when the opening / closing speed is higher, for example, when the hand is released, the acceleration is detected based on the opening / closing speed detected by the rotation sensor 72, and if it is determined that the rotation of the motor 6 cannot follow, the current to the motor 6 is increased. Is cut, the motor 6 is set in a free state, and damping control is performed near the fully closed or fully open position.

When it is detected by the signal from the position sensor 73 that the door 1 is at the predetermined position, the assist force by the motor 6 for assisting the opening and closing of the door 1 is controlled in the direction in which the assist force increases. .

When the opening / closing operation is performed from the door inner side (vehicle interior side) and the opening / closing operation is performed from the door outer side (vehicle outside),
Since a person who opens and closes the door 1 receives a different force, the driving force of the motor 6 is controlled so that the assist force changes according to the way the force is applied. Specifically, the inner handle switch 74 and the outer handle switch 75 detect whether the opening / closing operation is performed from the door inner side or the door outer side, and in the case of the opening operation from the door outer side, the initial operation is performed. Since it is easy to apply force and it is difficult to apply force at the end, the assist power is made small at the beginning and made large at the end. On the other hand, in the case of the opening operation from the door inner side, it is difficult to apply the force in the initial stage and the force is easily applied in the final stage, so the assist force is increased in the initial stage and decreased in the final stage. Also, in the case of the closing operation from the door outer side, it is difficult to apply the force when the closing operation is performed from a large opening, so the assist force is large, and the force is easily applied when the closing operation is performed from the small opening. To reduce. In the case of the closing operation from the door inner side, the force is easily applied when the closing operation is performed from a large opening, so the assist force is small, and the force is difficult to enter when the closing operation is performed from a small opening, so the assist force is increased. To do.

The torque sensor 71 detects the inclination state of the automobile, and the driving force of the motor 6 for assisting the opening and closing of the door 1 is controlled according to the inclination degree of the automobile. That is, the eccentric torque of the torque sensor 71 is detected, the inclination is judged based on the torque value and the torque direction, and when the inclination is in the direction of increasing the operating force, the assist force is increased while the inclination is in the direction of decreasing the operating force. If you cut the assist power.
However, during the opening operation from the door inner side, if the hand (or a part of the body) is released from the operation switch, the power unit 79 is short-circuited and the automatic stop is applied.

When the vehicle speed sensor 76 detects that the vehicle is in a drivable state, the operation of the motor 6 that assists the opening and closing of the door 1 is prohibited.

When the clearance sonar 78 detects that there is an obstacle in the opening / closing locus of the door, the operation of the motor 6 for assisting the opening / closing of the door 1 is prohibited.

By the position sensor 73, the door 1
When the fully open position and the fully closed position are detected, the motor 6 that assists the opening and closing of the door is controlled in the vicinity of these positions, and the assist force is reduced. Accordingly, a person who is opening and closing the door 1 can recognize that the door 1 is in the fully closed position or the fully open position.

When it is detected by the torque sensor 71 and the rotation sensor 72 that the reversing operation from the opening operation to the closing operation is a quick reversing operation, such as when getting on and off quickly, the reversing operation is performed without performing the normal control. The assist force on the warp side (closing direction) from the stop position is increased.

The priority order of control described above is as follows.
Table 2 below shows an example of a specific control map of the assist force in the order of inclination, rotation speed, torque, and obstacle.

[0048]

[Table 2] Next, the content of control will be specifically described with reference to FIG.

When starting, it is first determined whether or not an ignition key (not shown) is ON (step S).
1). If the ignition key is not ON, the vehicle is stopped and there is no possibility of opening or closing the door 1, so the motor 6 is freed (step S2).

If the ignition key is ON, it is then determined whether the vehicle speed V = 0 (step S3).
). If the vehicle speed is not V = 0, there is no possibility of opening and closing the door, so the motor 6 is made free (step S2).

If the vehicle speed V = 0, it is judged whether or not the operation is the inner side (step S4), and if it is the inner side operation, the inner operation map (portion relating to the inner operation in Table 2) is selected (step S4). On the other hand, if it is not the inner side operation, it is the outer side operation, and therefore the outer operation map (the part relating to the outer operation in Table 2) is selected (step S6).

Then, it is judged whether or not the vehicle is in the inclined state (step S7), and if it is the inclined state, the inclination map (Table 2
(Part related to operation when tilting) is selected (step S
8) On the other hand, if it is not in the tilted state, the normal map (the part other than the part related to the tilting operation in Table 2) is selected (step S9), and the signal from the position sensor 73 causes the door 1
It is determined whether or not the opening operation is started (step S10).

If the opening operation of the door is started, the rotation sensor 7
Whether the opening / closing speed of the door 1 is detected based on the signal from step 2 (step S11), and then the acceleration is calculated so that the rotation of the motor 6 can follow the change in the opening / closing speed of the door 1 by the operator. It is determined whether or not (step S12).

If it can follow, the door opening / closing operation force is detected by the signal from the torque sensor 71 (step S13), while if it cannot follow, the motor 6 is freed (step S2).

Then, it is judged whether or not the rotation of the motor 6 can follow the change in the opening / closing operation force of the door 1 (step S
14) If the tracking is not possible, the motor 6 is made free of rotation (step S2).

If it is possible to follow, it is judged whether or not there is an obstacle (step S15), and if there is an obstacle, the motor 6 is stopped to avoid collision (step S19).
If there is no obstacle, the position sensor 73 determines whether or not it is near the fully open position (step S16). If it is not near the fully open position, the process returns to step S15, and if it is near the fully open position, the motor 6 is controlled. (Step S17), the opening / closing speed of the door 1 is reduced to determine whether or not the door 1 is fully opened (step S18).

If it is fully opened, the motor 6 is stopped (step S19), while if it is not fully opened, the process returns to step S17.

The control in the case of the closing operation of the door 1 is performed in the same manner as in the case of the opening operation of the door 1, but the obstacle is not confirmed.

[0059]

As described above, according to the invention of claim 1, the assist force by the actuator for assisting the opening / closing of the door is controlled according to the opening / closing operation force of the door. It can be carried out.

According to the second aspect of the present invention, the assist force by the actuator for assisting the opening / closing of the door is controlled according to the opening / closing speed of the door. Therefore, the opening / closing of the door can be performed without feeling uncomfortable. .

According to the invention of claim 3, the assist force by the actuator for assisting the opening and closing of the door is controlled so that the assist force increases when the door reaches a predetermined position. Can assist.

According to the fourth aspect of the present invention, the driving force of the actuator is controlled so that the assist force varies depending on whether the door inner side is opened or closed and the door outer side is opened or closed. Therefore, the door outer side and the door inner side are controlled. It is possible to change the assist force according to the request.

According to the fifth aspect of the present invention, the driving force of the actuator for assisting the opening and closing of the door is controlled according to the degree of inclination of the vehicle. Therefore, the door can be opened and closed without difficulty even on a slope. it can.

According to the sixth aspect of the present invention, when the vehicle is in the traveling state, the operation of the actuator for assisting the opening and closing of the door is prohibited. Therefore, the door can be easily opened and closed in the traveling state of the vehicle. I will not be told.

According to the seventh aspect of the invention, when an obstacle is present in the opening / closing locus of the door, the operation of the actuator for assisting the opening / closing of the door is prohibited. There is no risk of adversely affecting the.

According to the eighth aspect of the invention, the actuator for assisting the opening and closing of the door is controlled near the fully open position and the fully closed position of the door to slow down the door speed. There is no danger of excessive force acting on the door near the closed position.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a vehicle door device.

FIG. 2 is a vertical sectional view of a door device of an automobile.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is an exploded perspective view showing motion converting means.

FIG. 5 is a sectional view of the same.

FIG. 6 is an explanatory diagram of arrangement of operation switches.

FIG. 7 is an explanatory diagram of an operation switch of an inner handle portion.

FIG. 8 is an explanatory diagram of an operation switch of an outer handle portion.

FIG. 9 is an explanatory diagram of an outer handle portion.

FIG. 10 is a cross-sectional view showing another operation switch section.

FIG. 11 is an exploded perspective view of an operation switch section.

FIG. 12 is an explanatory diagram of arrangement positions of various switches that form a control system.

FIG. 13 is a block diagram showing a control system.

FIG. 14 is a flowchart showing an example of a control system.

[Explanation of symbols]

1 Door 4 Assist force applying member 6 Motor (actuator) 36 Inner handle 37 Outer handle 61 Control unit 71 Torque sensor (operating force detecting means, inclination degree detecting means) 72 Rotation sensor (speed detecting means) 73 Position sensor (door opening / closing) Detection means, door position detection means) 74 Inner handle switch (opening / closing operation detection means) 75 Outer handle switch (opening / closing operation detection means) 76 Vehicle speed sensor (runnable state detection means) 78 Clearance sonar (obstacle detection means)

Claims (8)

[Claims] 1. A door opening / closing device for an automobile, in which an actuator is attached to the inside or outside of the door, the operating state of an operating portion provided on the door is detected, and the actuator assists opening / closing of the door. A door opening / closing for an automobile, comprising: an operating force detecting means for detecting a force; and a control means for receiving an output of the operating force detecting means and controlling an assisting force by the actuator according to an opening / closing operating force of the door. apparatus. 2. A door opening / closing device for an automobile, wherein an actuator is attached to the inside or outside of the door, the operating state of an operating portion provided on the door is detected, and the actuator assists opening / closing of the door. A door opening / closing device for an automobile, comprising: speed detecting means for detecting the speed of the vehicle; and control means for receiving an output of the speed detecting means and controlling the assist force of the actuator according to the opening / closing speed of the door. 3. A door opening / closing device for an automobile, wherein an actuator is attached to the inside or the outside of the door, the operating state of an operating portion provided on the door is detected, and the actuator assists opening / closing of the door. A door opening / closing detecting means for detecting the opening / closing state, and a control means for receiving the output of the door opening / closing detecting means and controlling the assisting force by the actuator in a direction in which the assisting force increases when the door reaches a predetermined position. Door opening and closing device for automobiles. 4. A door opening / closing device for an automobile, wherein an actuator is attached to the inside or outside of the door, the operating state of an operating portion provided on the door is detected, and the actuator assists opening / closing of the door, the door inner side of the door. Opening / closing operation detecting means for detecting whether the opening / closing operation is from the door outer side or the opening / closing operation from the door outer side, and an output from the door opening / closing operation detecting means, depending on whether the opening / closing operation is performed from the door inner side or the opening / closing operation from the door outer side. A door opening / closing device for an automobile, comprising: a control unit that controls a driving force of an actuator so that an assist force changes. 5. A door opening and closing device for an automobile, wherein an actuator is attached to the inside or the outside of the door, the operating state of an operating portion provided on the door is detected, and the actuator assists the opening and closing of the door. A door opening / closing device for a vehicle, comprising: a tilt degree detecting means for detecting the vehicle speed; and a control means for receiving an output of the tilt degree detecting means and controlling a driving force of an actuator according to a tilt degree of the vehicle. 6. A door opening and closing device for a vehicle, wherein an actuator is attached to the inside or the outside of the door, the operating state of an operating portion provided on the door is detected, and the actuator assists the opening and closing of the door. And a control means for receiving the output of the travelable state detection means and for inhibiting the operation of the actuator when the vehicle is in the travelable state. The car door opening and closing device. 7. An obstacle detecting means for detecting an obstacle in the opening / closing locus of the door, wherein the control means receives the output of the obstacle detecting means, and when there is an obstacle in the opening / closing locus of the door. 7. The vehicle door opening / closing device according to claim 1, wherein the operation of the actuator is prohibited. 8. A door position detecting means for detecting a fully open position and a fully closed position of the door, wherein the control means receives an output of the door position detecting means and operates an actuator near the fully open position and the fully closed position of the door. The vehicle door opening / closing device according to claim 1, wherein the door speed is controlled to reduce the door speed.