JPH02256546A - Seat belt device for automobile - Google Patents

Abstract

PURPOSE:To eliminate the trouble that a driver on a front seat is pressed, by installing a means which releases the locking operation by a locking mechanism for suppressing the pulling out-of a belt in the case when an impact is generated, when a rear door is opened, onto a retractor which is installed in the rear door and takes up a shoulder belt. CONSTITUTION:The shoulder belt part 2b of a seat belt which a driver takes is introduced into a rear door, passing through a belt guide installed on the front edge upper part of the rear door, and taken up onto a retractor 10. The retractor 10 is equipped with a locking mechanism 21 which acts onto a rotary body 20 fixed at the edge part of a taking-up shaft 19 and suppresses the revolution in the pulling-out direction of the shoulder belt 2b when an impact load over a prescribed value is generated on the car body. In this case, a lock releasing solenoid 27 which releases the pulling-out suppressing state of the shoulder part 2b by the locking mechanism 21 when a rear door 9 is opened is installed. Then, the turn of a locking lever 25 around a supporting shaft 24 is suppressed by the excitation of the solenoid 27.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a seat belt device for an automobile, especially for a front seat occupant! The present invention relates to a seat belt device for an automobile in which a retractor is provided on the rear door side to wind up an end portion of a shoulder belt that has been guided rearward through a section.

(Prior Art) For example, a seatbelt device for a front seat in a four-door pillarless hard-slab automobile is a seatbelt device that is guided diagonally upward from the inside side of the front seat toward the outside of the vehicle. The shoulder belt that has passed over the shoulders of the occupant is guided backward by being inserted into a guide member provided on the upper side of the outside of the vehicle of the seat back constituting the front seat, and the shoulder belt is further provided at the top of the rear door. Some belts are configured so that after passing through a belt guide, the end portion thereof is provided below the belt guide on the rear door side or is wound around the tractor.

By the way, as mentioned above, the retractor that winds up the end of the shoulder belt that has been guided rearward through the shoulders of the front seat occupant is subject to acceleration/deceleration that exceeds a predetermined value on the vehicle body during sudden braking or a collision. A locking mechanism is installed inside the vehicle to protect the front seat occupant by preventing the shoulder belt from being pulled out when the front seat belt is pulled out. Therefore, in the case where the retractor is installed on the rear door side as described above, when the rear door is opened or closed vigorously, the locking mechanism built into the retractor becomes activated and prevents the shoulder belt from being pulled out. If the rear door is opened with the shoulder belt being prevented from being pulled out, the shoulder belt may be pulled rearward as the rear door opens. As a result, it is conceivable that the chest and shoulders of the front seat occupant will be compressed, and that the smooth opening operation of the rear door will be hindered.

To deal with this, for example, Japanese Patent Application Laid-Open No. 63-269755
As disclosed in the publication, a retractor is provided on the rear door side to wind up the end of the shoulder belt that is led rearward through the shoulders of the front seat occupant in the same manner as above. By configuring the locking sensitivity of the internal locking mechanism to be reduced when the rear door is opened and preventing unnecessary operation of the locking mechanism as much as possible, the above-mentioned problems when opening the rear door can be solved. It has become so.

(Problem to be Solved by the Invention) However, as described above, in addition to providing a retractor on the rear door side that winds up the end of the shoulder belt, the locking sensitivity of the locking mechanism built into the retractor is adjusted to prevent the rear door from opening when the rear door is opened. Even if the vehicle is configured to be lower than when closed, if an acceleration or deceleration of more than a predetermined value is applied to the vehicle body, for example, when driving on a bumpy road, during sudden braking during normal driving, or during a collision, Naturally, the locking mechanism becomes activated and prevents the shoulder belt from being pulled out, and when the rear door is opened with the shoulder belt being prevented from being pulled out. , the shoulder belt would be pulled backwards as the rear door opened, putting pressure on the chest and shoulders of the front seat occupants and potentially making it impossible to open the rear door smoothly. .

The present invention addresses the above-mentioned circumstances by winding up the end of the shoulder belt that passes through the shoulders of the front seat occupant and is led rearward, and at the same time winds up the end of the shoulder belt that passes through the shoulders of the front seat occupant and prevents the vehicle body from accelerating or decelerating beyond a predetermined value. In an automobile seat belt device in which a retractor is provided on the rear door side and has a locking mechanism that prevents the shoulder belt from being pulled out when the rear door is activated, the locking mechanism built into the retractor prevents the shoulder belt from being pulled out when the rear door is opened. An object of the present invention is to enable a rear door to be opened smoothly without putting pressure on the chest or shoulders of a front seat occupant by preventing the front seat occupant from being forced to do so.

(Means for Solving the Problems) In order to solve the above problems, the present invention is characterized by the following configuration.

That is, the invention according to the first claim of the present application (hereinafter referred to as the first invention) winds up the end of the shoulder belt that has been guided rearward through the shoulders of the front seat occupant, and also winds up the end of the shoulder belt that has been guided rearward through the shoulders of the front seat occupant. In an automobile seat belt device in which a rear door is provided with a retractor having a locking mechanism that prevents the shoulder belt from being pulled out when an acceleration/deceleration of a predetermined value or more is applied, the shoulder belt is pulled out by the locking mechanism when the rear door is opened. It is characterized by comprising a lock release means for releasing the blocked state.

Further, the invention according to the second claim of the present application (hereinafter referred to as the second invention) provides, in addition to the first invention, a control means for terminating the operation of the lock release means in a predetermined time. Features.

Furthermore, the invention according to the third claim of the present application (hereinafter referred to as the third invention) winds up the end of the shoulder belt that is led rearward through the shoulders of the front seat occupant, and also wraps the end of the shoulder belt that is guided rearward through the shoulder of the passenger in the front seat. In an automobile seat belt device in which a rear door is equipped with a lock mechanism that prevents the shoulder belt from being pulled out when an acceleration/deceleration of more than a predetermined value is applied, the lock sensitivity of the lock mechanism is determined when the rear door is opened or closed. The present invention is characterized in that it is provided with a sensitivity reducing means for reducing the speed of the vehicle, and a lock releasing means for releasing the state in which the shoulder belt is prevented from being pulled out by the locking mechanism when the rear door is opened.

(Function) According to the first invention, even if the locking mechanism provided on the retractor prevents the shoulder belt from being pulled out, when the rear door is opened, the unlocking means releases the shoulder belt.
The state in which the locking mechanism prevents the shoulder belt from being pulled out is released, and as a result, when the rear door is opened, the shoulder belt is pulled out by the retractor, and the shoulder belt is prevented from opening the rear door. As a result, being pulled backwards is reliably prevented. As a result, the rear door can be opened smoothly without putting pressure on the front seat occupant's chest or shoulders.

Furthermore, as in the first invention described in -E, when the rear door is opened, the lock release means releases the locking mechanism from blocking the shoulder belt from being pulled out, and when the rear door is opened, collision may occur. When an impact load of a predetermined value or more (in this case, an acceleration of a predetermined value or more) is applied to the vehicle body due to such reasons, a situation may occur in which the locking mechanism is unable to prevent the shoulder belt from being pulled out. However, in particular, according to the second invention, the control means causes the operation of the lock release means to end in a predetermined time, so that the control means controls the time required to fully open the rear door. By configuring the unlocking means to operate within the vehicle, the locking mechanism prevents the shoulder belt from being pulled out even when an impact load of a predetermined value or more is applied to the vehicle body with the rear door fully open as described above. This allows the front seat occupants to be reliably protected.

Furthermore, according to a third aspect of the present invention, a sensitivity reducing means is provided for reducing the locking sensitivity of the locking mechanism when the rear door is opened/closed, so that when the rear door is opened forcefully, the sensitivity of the rear door exceeds a predetermined value. This ensures that the locking mechanism is prevented from operating unnecessarily due to vibrations caused by vehicle body vibrations caused when acceleration is applied or when the rear door is closed with strong force. performance can be further improved.

(Example) Embodiments of the present invention will be described below based on the drawings.

First, the overall configuration of this embodiment will be explained with reference to FIG.
This embodiment relates to a seat belt device installed in the front seat of a four-door pillarless hardtop vehicle. ) has a lap belt part 2a that restrains the waist part and a shoulder belt part 2b that restrains the shoulder part. The lap belt portion 2a is
One end is fixed to the lower part of the outer side of the front seat 3 using an anchor member 4, and the seat belt 2 is guided from the end to the inner side of the front seat 3. The tongue plate 5 inserted through the front seat 3 is engaged with a buckle 6 provided on the side of the front seat 3 on the inside of the vehicle, thereby restraining the waist of the occupant. The shoulder belt portion 2b extends diagonally upward from the engagement portion between the tongue plate 5 and the buckle 6, and is provided on the seat side provided on the upper side of the seat back 3a on the outside of the vehicle that constitutes the front seat 3. By being inserted through the belt guide 7, the belt restrains the occupant's chest and shoulders on the outside of the vehicle. The shoulder belt portion 2b that has passed through the seat side belt guide 7 and is guided rearward has a front end portion rotatably supported by a hinge pillar portion 8 via a hinge member (not shown) at a rear door 9. The end portion thereof is provided inside the rear door 9 or wound around the tractor 10.

A door opening/closing detection switch 11 is provided at a predetermined position on the vehicle body facing the rear end of the rear door 9 to detect whether the rear door 9 is open or closed. When the rear door 9 is opened, the rear door opening/closing detection switch 11 11 is in the ON state, for example, the instrument panel (not shown)
The open state of the rear door 9 is displayed by lighting up an indicator installed in the rear door 9, and when the rear door 9 is closed, the rear door opening/closing detection switch 11 is configured to be in the OFF state.

Now, to explain in detail the structure of the door side belt guide 12 which is provided above the front end of the rear door 9 and through which the shoulder belt part 2b is inserted, as shown in FIG. A mounting bracket 15 is fixed to the upper part of the inner panel 13 forming the rear door 9 via a plurality of mounting bolts 14...14, and an insertion hole 16a for the shoulder belt portion 2b is formed in the mounting bracket 15. The guide member 16 is fixedly provided. Then, the insertion hole 16
a has a substantially arc shape, so that even if the insertion direction of the shoulder belt portion 2b changes due to opening and closing of the rear door 9, the belt portion 2b can always be guided smoothly, and the insertion hole The end portion of the shoulder belt portion 2b that has passed through the shoulder belt portion 16a is wound around the retractor 10.

In addition, in this embodiment, the mounting bracket 15
The guide member 16 is covered by a door trim 17 disposed on the interior side of the inner panel 13, so that the guide member 16 has an insertion hole 16a.
Correspondingly, a cover member 18 having an arc-shaped insertion hole 18a through which the shoulder belt portion 2b is inserted is also integrally assembled to the door trim 17.

In this embodiment, the retractor 10, which is provided below the rear door 9 and winds up the end of the shoulder belt portion 2b that has passed through the door-side belt guide 12, is configured as follows.

That is, as shown enlarged in FIG. 3, this retractor 1
0 is a winding shaft 1 around which the end of the shoulder belt part 2b is wound, and which is biased by a spring or the like in the direction of winding up the shoulder belt part 2b (in the direction of arrow a).
9, a rotating body 20 fixed to the end of the shaft 19 and rotating integrally, and an impact load (acceleration/deceleration) of a predetermined value or more on the vehicle body.
The lock mechanism 21 acts on the rotating body 20 to prevent the shoulder belt portion 2b of the winding shaft 19 from rotating in the pull-out direction (in the direction indicated by the arrow).

The locking device 1121 can be moved in any direction when an impact load is applied by engaging the protrusion 22a provided at the center of the lower surface with the engagement hole 23a formed at the center of the frame member 23. A weight member 22 is tiltably supported and has a concave upper surface 22b, and is pivotally supported by the frame member 23 so as to be swingable about a support shaft 24,
and a protrusion 2 received by the concave surface 22b at a predetermined position on the lower surface.
When the weight member 22 is tilted when an impact load is applied, the protrusion 25a of the lock lever 25, which is received by the concave surface 22b on the upper surface thereof, is lifted up. As a result, the lock lever 25 swings about the support shaft 24, so that its tip 25b engages the plurality of pawls 20a formed around the outer periphery of the rotating body 20.
20a, the rotating body 20 or the winding shaft 19 is prevented from rotating in the direction in which the shoulder belt portion 2b is pulled out.

Further, the retractor 10 includes a lock sensitivity reducing solenoid 26 that reduces the lock sensitivity of the lock mechanism 21 when the rear door 9 is opened and closed, and a state in which the lock mechanism 21 prevents the shoulder belt portion 2b from being pulled out when the rear door 9 is opened. Lock release solenoid 27 to release the
are provided for each.

The main body 26a of the lock sensitivity reducing solenoid 26 is attached to a predetermined position of the retractor 10, and the lock sensitivity reducing solenoid 26 is attached to a predetermined position of the retractor 10.
The tip 26c of the plunger 26b at 6 is supported near the side of the support shaft 24 of the lock lever 25, and the lock sensitivity reducing solenoid 26 detects whether the rear door 9 is in the open state by the rear door opening/closing detection switch 11. When detected, the lock lever 25 is energized and activated to hold the lock lever 25 so that it does not rotate about the support shaft 24.

Further, the lock release solenoid 27 has its main body 2
7a is attached to a predetermined position of the retractor 10, and the tip 27C of the plunger 27b in the lock release solenoid 27 is further attached to the tip 26c of the plunger 26b in the lock sensitivity reducing solenoid 26 supported by the lock lever 25. The lock release solenoid 27 is energized and activated when the rear door opening/closing detection switch 11 detects the open state of the rear door 9, and the lock release solenoid 27 is energized and activated to control the rotation "tIE20". By disengaging the tip 25b of the lock lever 25, which constitutes the locking mechanism 21, which is engaged with the claw 20a formed on the outer periphery, from the claw 20a,
The state in which the locking mechanism 21 prevents the shoulder belt portion 2b from being pulled out is released.

Here, the operating states of the lock sensitivity reduction solenoid 26 and the lock release solenoid 27 will be explained in more detail based on the time chart shown in FIG. 4. As shown in the figure, the rear door open/close detection switch 11 causes When the open state of the rear door 9 is detected, that is, when the detection switch 11 is turned on, the lock sensitivity reduction solenoid 26 and the lock release solenoid 27 are respectively energized and activated. become. The lock sensitivity reduction solenoid 26 operates in a predetermined manner after the rear door open/close detection switch 11 detects that the rear door 9 is opened and after the detection switch 11 detects that the rear door 9 is closed. The operating time is set so that it will be in the operating state until the time elapses. The unlocking solenoid 27 is activated when the door switch 11 detects that the rear door 9 is open, and the unlocking solenoid 27 is activated when the door switch 11 detects that the rear door 9 is opened. The operation is configured to end when a predetermined time has elapsed after the condition is detected, that is, when the time required to fully open the rear door 9 has elapsed.

The lock sensitivity reduction solenoid 26 and the lock release solenoid 27 are activated when the rear door 9 is opened, regardless of the ignition switch's ON-OFF state, that is, whether the engine is stopped or started. There is. Further, the lock sensitivity reducing solenoid 26 is configured so that when the rear door 9 is rMr:R, the tip 25b of the lock lever 25 is connected to the pawl 20a on the rotating body 20.
The lock lever 25 is restrained from swinging so that the lock lever 25 does not engage with the claw 2 on the rotating body 20.
The tip 25b of the lock lever 25 is engaged with 0a.
Therefore, the lock sensitivity reducing solenoid 26 does not have enough operating force to detach from the claw 20a.
The operating force is set smaller than the operating force of the lock release solenoid 27.

Next, the operation of this embodiment will be explained.

When a passenger is seated on the front seat 3, as shown in FIG. When the seat belts 2 are fitted together, the lap belt portion 2a of the seat belt 2 is placed over the occupant's waist, and the shoulder belt portion 2b is placed over the occupant's chest or shoulder on the outside of the vehicle.

Here, during normal running, as shown in FIG.
Since it is not engaged with the pawl 20a formed on the outer periphery of the rotating body 20 fixed to the winding shaft 19 of b, the rotating body 2
The take-up shaft 19 can rotate in the direction in which the shoulder belt portion 2b is pulled out, so that the occupant of the front seat 3 can move his or her body relatively freely.

When an impact load of a predetermined value or more is applied to the vehicle body due to sudden braking or a collision, the lock lever 25 is swung upward by the weight member 22 and the lock lever 25 is swung about the support shaft 24. When the winding shaft 19 is moved, its tip 25b engages with a claw 20a formed on the outer periphery of the rotating body 20, thereby preventing rotation of the rotating body 20 and the winding shaft 19 in the above direction. As a result, the occupant is seated in the front seat 3 by the shoulder belt portion 2b.
This means that the occupant is protected from the impact.

By the way, as described above, when attempting to open the rear door 9 in a state where the locking mechanism 21 prevents the shoulder belt portion 2b from being pulled out, the open state of the rear door 9 is detected by the rear door opening/closing detection switch 11. When the lock lever 25 is detected, the lock release solenoid 27 is activated, and the lock release solenoid 27 is activated.
The tip 25b of the claw 20 on the outer periphery of the rotating body 20
a, the locking mechanism 21 releases the state in which the shoulder belt portion 2b is prevented from being pulled out, and as a result, when the rear door 9 is opened, the shoulder belt portion 2b is released from the retractor 10. As a result, the shoulder belt portion 2b is reliably prevented from being pulled rearward when the rear door 9 is opened. As a result, the rear door 9 can be opened smoothly without putting pressure on the chest or shoulders of the front seat occupant.

Further, as described above, when the lock release solenoid 27 is configured to release the state in which the lock mechanism 21 prevents the shoulder belt portion 2b from being pulled out when the rear door 9 is opened, when the rear door 9 is opened, When an impact load of a predetermined value or more (in this case, an acceleration of a predetermined value or more) is applied to the vehicle body due to a collision or the like, the locking mechanism 21 is unable to prevent the shoulder belt portion 2b from being pulled out. However, according to this embodiment, the lock release solenoid 27 completes its operation within the time required to fully open the rear door 9. After the locking mechanism 21 is fully opened, the locking mechanism 21 becomes operable again. Therefore, even when an impact load of a predetermined value or more is applied to the vehicle body with the rear door 9 fully opened as described above, the locking mechanism 21 is activated again. This makes it possible to prevent the shoulder belt portion 2b from being pulled out, thereby reliably protecting the front seat occupant.

Furthermore, in this embodiment, the operation is performed from when the open state of the rear door 9 is detected by the rear door opening/closing detection switch 11 to when a predetermined period of time has elapsed after the detection switch 11 detects that the rear door 9 is closed. When the lock sensitivity reduction solenoid 26 that reduces the lock sensitivity of the lock mechanism 21 is activated between This ensures that the locking mechanism 21 is prevented from operating unnecessarily due to vibrations of the vehicle body caused when the rear door 9 is closed with strong force, thereby further improving the reliability of the retractor 10. can be improved.

In this embodiment, as shown in FIG. 3, the plunger 27b in the lock release solenoid 27 is
Since the tip 27c of the plunger 27c is supported further outward than the tip 26c of the first plunger 26b in the lock sensitivity reduction solenoid 26, the distance between the tip 27c of the plunger 27b and the support shaft 24 is set longer. When the lock lever 25 is rotated about the support shaft 24 by the lock release solenoid 27, the rotational moment acting on the lock lever 25 becomes large, and as a result, the operating force of the lock release solenoid 27 is increased. can be set small, and the lock release solenoid 27 can be made smaller.

Furthermore, in this embodiment, the operating force of the lock release solenoid 27 is set to be greater than that of the lock sensitivity reduction solenoid 26, but this is due to the fact that the operating force of the lock release solenoid 27 is greater than that of the lock sensitivity reduction solenoid 26. This can be easily achieved by appropriately selecting the number of windings, current capacity, etc. of each of the solenoids 26 and 27.

5.6 shows another embodiment, and the one shown in FIG. 5 includes a lock sensitivity reducing solenoid 26' and a lock release solenoid 27' having the same structure as the first embodiment. A bar member 28'29' is fixed to the tip of each plunger 26b', 27b', and by operating the sensitivity reduction solenoid 26', the bar member 28', 29' is fixed as shown by the chain line. The member 28' is moved upward to lock the lever member 28'.
The support shaft 2 of the lock lever 25' is brought into contact with the rear end of the lock lever 25'.
4', and when the tip 25b' of the lock lever 25' is resting on the pawl 20a' of the rotating body 20', the lock release solenoid 27 ', as shown by the chain line, moves the bar member 29' upward and pushes up the rear end of the lock lever 25', thereby rotating the tip 25b' of the lock lever 25'. body 20'
It is designed to be detached from the claw 20a' at.

According to this, effects similar to those of the first embodiment described above can be exhibited.

Furthermore, in the one shown in FIG. 6, one end is pivotally supported by a fulcrum 30'' in parallel with a lock lever 25'' supported swingably about a support shaft 24'', and a lever member is attached to the other end. 3
A rocking lever 32'' to which 1 to 1 is fixed is provided,
The tips of the plungers 26b'' and 27b'' of the lock sensitivity reducing solenoid 26'' and the lock release solenoid 27'', which have the same structure as in the first embodiment, are connected to the side of the fulcrum 30'' of the swing lever 32''. The sensitivity reducing solenoid 26″
, the lever member 31'' fixed to the other end of the swing lever 32'' is brought into contact with the rear end of the lock lever 25'', and the support shaft 24'' of the lock lever 25'' is rotated. In addition to regulating the rocking around the center, the lock lever 2
When the distal end 25b of the 5'' is stopped by a pawl on a rotating body (not shown), the lever member 31'' is moved upward by activating the lock release solenoid 27''. By moving the lock lever 25'' up and pushing up the rear end of the lock lever 25'', the tip 25b'' of the lock lever 25'' is released from the pawl on the rotating body. According to this, the same effects as in the above-mentioned Embodiment 1.2 can be achieved.

(Effects of the Invention) As described above, according to the first invention of the present application, even if the shoulder belt is prevented from being pulled out by the locking mechanism provided on the retractor, the lock releasing means is activated when the rear door is opened. , the state in which the locking mechanism prevents the shoulder belt from being pulled out is released, and as a result, when the rear door is opened, the shoulder belt can be pulled out by the retractor, and the shoulder belt prevents the opening operation of the rear door. This will reliably prevent the vehicle from being pulled backwards. As a result, the rear door can be opened smoothly without putting pressure on the front seat occupant's chest or shoulders.

Further, according to the second aspect of the invention, the control means causes the operation of the lock release means to be completed within a predetermined time, so that the control means can release the lock within the time required to fully open the rear door. By configuring the means to operate, after the rear door is fully opened, the locking mechanism becomes operable again, thereby preventing an impact load exceeding a predetermined value from being applied to the vehicle body when the rear door is fully opened. Even if the shoulder belt is activated, the locking mechanism can prevent the shoulder belt from being pulled out, and the front seat occupant can be reliably protected.

Furthermore, according to the third invention, a sensitivity reducing means is provided for reducing the locking sensitivity of the locking mechanism when the rear door is opened and closed (from the time the rear door is opened until a predetermined time has elapsed after the time the rear door is closed). As a result, the locking mechanism may operate unnecessarily due to vibrations of the vehicle body caused when the rear door is forcefully opened and an acceleration of more than a predetermined value is applied to the rear door, or when the rear door is closed with strong force. This will reliably prevent this, and as a result, the reliability of the retractor can be further improved.

[Brief explanation of drawings]

The drawings show an embodiment of the automobile seat belt device according to the present invention. FIG. 1 is a schematic perspective view showing the overall configuration of the automobile seat belt device according to the present embodiment, and FIG. FIG. 3 is a schematic configuration diagram showing the configuration of the beam tractor; FIG. 4 is a time chart showing the operating states of the lock sensitivity reduction solenoid and the lock release solenoid. , 5.6 are schematic configuration diagrams showing other embodiments of a mechanism for reducing the locking sensitivity of the locking mechanism and releasing the locked state by the locking mechanism, respectively. DESCRIPTION OF SYMBOLS 1... Seat belt device, 2b... Shoulder belt (shoulder belt part), 9... Rear door, 10...
Retractor, 21...lock mechanism, 26°26',
26''...Sensitivity reducing means (lock sensitivity reducing solenoid), 27.27', 27''...Lock release means (
lock release solenoid). Figure 5

Claims (3)

[Claims] (1) A locking mechanism that winds up the end of the shoulder belt guided rearward through the shoulders of the front seat occupant and prevents the shoulder belt from being pulled out when acceleration/deceleration of a predetermined value or more is applied to the vehicle body. A seat belt device for an automobile in which a retractor having a retractor is provided on a rear door, characterized in that the seat belt device is provided with a lock release means for releasing the state in which the shoulder belt is prevented from being pulled out by the lock mechanism when the rear door is opened. Automobile seat belt device. (2) A locking mechanism that winds up the end of the shoulder belt guided rearward through the shoulders of the front seat occupant and prevents the shoulder belt from being pulled out when acceleration/deceleration of a predetermined value or more is applied to the vehicle body. A seatbelt device for an automobile in which a retractor having a retractor is provided on a rear door includes a lock release means for releasing a state in which the shoulder belt is prevented from being pulled out by the lock mechanism when the rear door is opened, and a predetermined operation of the lock release means. A seat belt device for an automobile, characterized in that it has a control means for ending it in time. (3) A locking mechanism that winds up the end of the shoulder belt guided rearward through the shoulders of the front seat occupant and prevents the shoulder belt from being pulled out when acceleration/deceleration of a predetermined value or more is applied to the vehicle body. A seatbelt device for an automobile, in which a retractor is provided on a rear door, the sensitivity reducing means reducing the locking sensitivity of the locking mechanism when the rear door is opened and closed, and a shoulder belt provided by the locking mechanism when the rear door is opened. A seat belt device for an automobile, comprising: a lock release means for releasing a state in which the seat belt is prevented from being pulled out.