JPH0415560Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a seatbelt retractor for retracting webbing in a seatbelt installed in a vehicle to restrain an occupant in an emergency.
In particular, the present invention relates to improvements in seatbelt retractors that use a motor to retract webbing.

[Prior art and its problems]

Winding up the webbing in a seatbelt retractor has traditionally been done using a mainspring spring, but if the webbing is retracted using a mainspring spring, the occupant can use the spring force of the mainspring to retract the webbing to the required length. If the webbing is pulled out and put on, the tension of the webbing is strong, giving the wearer a feeling of pressure. Furthermore, if an attempt was made to reduce the spring force of the mainspring spring to eliminate the feeling of pressure on the wearer, there was a risk that the webbing would not be safely wound up and stored when stored. For this reason, in recent years seatbelt retractors have been developed in which the webbing is retracted by a motor so that the optimal tension of the webbing is always obtained so as not to give a feeling of pressure when worn. As described above, as a seat belt retractor in which the webbing is retracted by a motor, the one described in Japanese Utility Model Application Publication No. 179256/1983 is known. A guide roller is provided on the side of the planetary gear mechanism with a webbing wound around it and moved by the tension of the webbing, and one end of a lever-shaped tie plate is connected to the rotating shaft of this guide roller. An electrical connection piece protruding from the other end contacts different contacts as the guide roller moves, thereby controlling the motor.

However, when the movable guide roller is provided on the side of the planetary gear mechanism, the structure becomes complicated and there is a problem that it is impossible to reduce the size and weight of the planetary gear mechanism.

Furthermore, as shown in Japanese Utility Model Application Publication No. 60-90050, it has been known that the main winding mechanism for the webbing is a mainspring spring, and the torque of the mainspring spring is changed by controlling a motor. However, this also has the problem of a complicated structure, which makes it impossible to reduce the size and weight, and also increases costs.

[Purpose of invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a seat belt retractor that overcomes the problems of the conventional seat belt retractor described above and that has a simple structure and can always provide optimum tension.

[Summary of the idea]

The present invention includes an arm member fixed to a winding shaft for winding webbing, a planetary gear rotatably supported by the arm member, and a planetary gear disposed coaxially with the winding shaft and meshing with the planetary gear. an internal gear which is provided with a sun gear, a lock means for preventing rotation of the sun gear, a motor for rotationally driving the sun gear, and a switch body, and which is arranged coaxially with the winding shaft and meshes with the planetary gear; a spring member that applies a rotational force in the winding direction of the webbing to the internal gear; a buckle switch that is turned ON when the tongue is inserted into the buckle body when the webbing is attached; a first control contact group for detecting the torque applied to the internal gear from the spring member by contacting the switch body of the internal gear according to the rotation of the internal gear; and a first control contact group for detecting the torque applied to the internal gear from the spring member; a second control contact group that detects a larger torque than the first control contact group; and driving the motor when the detected torque of each control contact group is smaller than a predetermined torque;
The present invention is characterized by comprising a control circuit which operates a locking means for stopping the motor and preventing rotation of the sun gear when the torque is equal to a predetermined torque, and releases the locking means when the torque exceeds a predetermined torque.

[Example of idea]

The present invention will be explained below with reference to embodiments shown in the drawings.

1 and 2 show the mechanical configuration of a seat belt retractor according to the present invention, in which a housing 1 rotatably supports a take-up shaft 2 disposed within the housing 1. One end of the webbing 3 is attached to the take-up shaft 2, and the webbing 3 is wound up as the take-up shaft 2 rotates. A boss 5 of a disc 4 as an example of an arm member is fitted onto one end 2A of the winding shaft 2 facing outside the housing 1, and the winding shaft 2 and the disc 4 are coaxially arranged. are designed to be able to perform rotational movements as a unit. A pin 6 is provided protruding from the outside of one side of the disk 4, and a planetary gear 7 is rotatably fitted into this pin 6.

The winding shaft 2 is attached to one end 2A of the winding shaft 2.
A sun gear 8 coaxial with the winding shaft 2 is loosely fitted so that it can rotate independently of the winding shaft 2, and a small diameter first gear 9A of this sun gear 8 meshes with the planetary gear 7. Further, the sun gear 8 is formed with a large-diameter second gear 9B and a tooth portion 9C. moreover,
A motor 10 is disposed within the housing 1, and a gear 12 is attached to a rotating shaft 11 of the motor 10.
is fitted. Furthermore, an idler gear 15 is rotatably loosely fitted to the shaft portion 14 of the support body 13 stretched outside the housing 1, and the idler gear 15 is connected to the second gear 9B of the sun gear 8 and They mesh with the gears 12, respectively, and transmit the rotation of the rotating shaft 11 of the motor 10 to the sun gear 8. Note that the motor 10 is a general low-cost small motor that is not equipped with a brake device.

A lever 16 as an example of a locking device for the motor 10 is swingably supported at its intermediate portion by a pin 17 on the housing 1, and one end of the lever 16 has teeth of the sun gear 8. 9C
A tooth portion 18 that meshes with the sun gear 8 to restrain rotation of the sun gear 8.
is formed. Further, a solenoid 19 supported by the housing 1 is connected to the other end of the lever 16.
When the solenoid 9 is energized, the solenoid 19 causes the lever 16 to swing clockwise in FIG. Seshime, motor 1
0 is in a free rotation state. Note that when the solenoid 19 is not energized, the coil spring 19A that biases the lever 16 counterclockwise causes the tooth portion 18 to mesh with the tooth portion 9C to restrain the rotation of the sun gear 8, thereby substantially stopping the motor 10. It's starting to lock into place.

An internal gear 20 coaxially arranged with the disc 4 is loosely fitted onto the outer periphery of the boss 5 of the disc 4 so as to be able to rotate independently of the disc 4. The disc 4, the planetary gear 7, the sun gear 8, and the internal gear 20 mesh with the gear 7, and thus constitute a planetary gear mechanism. Further, a coil spring 21 is interposed between the internal gear 20 and the support body 13 to apply a rotational force to the internal gear 20 in the winding direction of the webbing 3. on the other hand,
A protrusion 22 is provided on the outer peripheral surface of the internal gear 20, and the protrusion 22 is provided on the housing 1.
A pair of stoppers 23A and 23B are protruded from each other and are arranged at an angle of about 120 degrees between them, and when the internal gear 20 rotates in both directions, the protrusion 22 comes into contact with both stoppers 23A and 23B. It is now being stopped by moreover,
A switch body 24 is provided in a protruding manner on the protrusion 22 .

A base 25 is protruded from the outer corner of the housing 1, and the base 25 has the protrusion 2.
Arc-shaped contact support 26 facing the movable range of 2
is supported. As an example, six control contacts 27A, 27B, 27C, 27D,
27E, 27F (hereinafter collectively referred to as 27) are attached, and each control contact 27 is located at a position corresponding to the set approximate torque of the tension of the webbing 3, for example, when the approximate torque of the tension of the webbing 3 is controlled. Contact 27A is 4.5Kg・mm, 27B is 6.0
Kg・mm, 27C is 7.0Kg・mm, 27D is 9.0Kg・
mm, 27E is provided at a position where it operates when the pressure is 11.0Kg・mm, and 27F is provided at a position where it operates when the pressure is 12.0Kg・mm.

Among the control contacts 27 described above, contacts 27A to 2
7C constitutes a first control contact group that operates when the tongue is inserted into the buckle body (not shown) when the webbing is bonded, that is, when the buckle switch 28 (Fig. 3) is turned on. In addition, the contacts 27D to 27F are
When the webbing is not attached to the buckle,
That is, they constitute a second control contact group that operates when the buckle switch 28 is turned off.

FIG. 3 shows a control mechanism for controlling the motor 10 and the solenoid 19 of the lock device, which has a control circuit 29 into which signals from each control contact 27 and buckle switch 28 are input. At least one of the motor 10 and the solenoid 19 is energized by a control signal from the control circuit 29. When a signal from the control contact 27A or 27D is input to the control circuit 29, the solenoid 19 is driven to unlock the sun gear 8, and the motor 10 is driven to rotate the winding shaft 2. and wind up webbing 3. In addition, the control contact 2
When the signal from 7B or 27E is input to the control circuit 29, the drive of the motor 10 is stopped, the solenoid 19 is deenergized, and the coil spring 1
The sun gear 8 is locked by the action of 9A. Further, when a signal from the control contact 27C or 27F is input to the control circuit 29, the solenoid 19 is driven and the sun gear 8 is unlocked, so that the sun gear 8 and the motor 10 are in a free rotation state. Furthermore, the buckle switch 28
changes from OFF to ON, the control contact 2 mentioned above
Similarly to 7C and 27F, the solenoid 19 is driven to unlock the sun gear 8, and the sun gear 8 and motor 10 are in a free rotating state. Conversely, when the buckle switch 28 is turned from ON to OFF, the aforementioned control Similar to the contacts 27A and 27D, the solenoid 19 is driven to unlock the sun gear 8, and the motor 10 is driven to rotate the winding shaft 2 to wind up the webbing 3.

Next, the operation of the above-described embodiment will be explained with reference to the flowchart of FIG.

In the initial state shown in Fig. 4, the webbing 3 is attached to the take-up shaft 2.
In this state, the tongue is detached from the buckle body, so the buckle switch 28 is turned off, and the switch body 24 attached to the protrusion 22 of the internal gear 20 is not controlled. Opposite contact 27E for
As shown in ST ₁ , this control contact 27E is ON
is being used. The motor 10 is therefore stopped and the sun gear 8 is locked by the teeth 18 of the lever 16 (step ST ₂ ).

Step ST ₃ from the state of step ST ₂ described above.
When the webbing 3 is pulled out as shown in
The disc 4 integral with the disc 4 rotates clockwise in FIG. and rotate clockwise in FIG. As a result, the torque due to the tension of the webbing 3 increases, and the control contact 27E
OFF, and instead, control contact 27F turns ON as shown in step _ST4 . Then, the solenoid 19 is driven, and the teeth 18 of the lever 16 are separated from the teeth 9C of the sun gear 8, resulting in a free winding state as shown in step _ST5 , and the internal gear 20 is moved away from the coil spring 21. The spring force causes the sun gear 8 to rotate counterclockwise in FIG. 1, and the control contact 27E is turned ON again as shown in step ST ₆ , and the sun gear 8 is restrained by the lever 16 and becomes the winding lock again (step ST ₇₎ . ). In this way, when the webbing 3 is pulled out, the control contacts 27E and 2
7F will alternately repeat ON and OFF.

When the tongue is attached to the buckle body in the state of step ST ₇ described above, the buckle switch 28
turns from OFF to ON as shown in step ST ₈ , and as a result, the solenoid 19 is driven and the lever 16 is separated from the sun gear 8, resulting in step ST _9.
As shown in the figure, the winding becomes free. Therefore, the internal gear 20 rotates counterclockwise in FIG. 1 due to the spring force of the coil spring 21, and the switch body 24 first contacts the control contact 27D, but
This control contact 27D is connected to the buckle switch 28.
Since it is a switch that operates only when it is OFF, it does not operate in this state, and then the switch body 2
4 is the control contact 2 as shown in step _ST10 .
Contact 7C. However, this control contact 27
The function of C is when the buckle switch 28 changes from OFF to ON.
Since it _is the same as the function when switching to
7B turns ON. Then, the solenoid 19 is deenergized and the teeth 18 of the lever 16 mesh with the teeth 9C of the sun gear 8, resulting in a winding lock state as shown at step _ST12 . This is a state in which the webbing 3 is wound around the passenger's body, but as described above, the control contact 27B
The tension of the webbing 3 when is set to ON is that the torque of the coil spring 21 in that state is 6.0.
Since it is small (kg/mm), the webbing 3 will not put unnecessary pressure on the occupant's body.

Next, when the webbing 3 is pulled out from the state of step ST ₁₂ described above (step ST ₁₃ ), since this state is a winding lock state in which the rotation of the sun gear 8 is restrained, the webbing 3 is pulled out as the winding shaft 2 rotates. The internal gear 20 then rotates clockwise in FIG. 1 against the coil spring 21, and the control contact 27C is turned on as shown at step _ST14 . This control contact 27C has the same function as the control contact 27F, and as a result, as shown in step _ST15 , the winding is free, and the internal gear 20
is rotated counterclockwise in FIG. 1 by the spring force of the coil spring 21, and the control contact 27B is turned on again as shown at step _ST16 , and the winding lock state is again established (step _ST17 ).

When the webbing 3 is further wound up from the state of step ST ₁₇ (step ST ₁₈ ), the tension of the webbing 3 decreases, so the gear gear 20 is moved counterclockwise in FIG. 1 by the spring force of the coil spring 21. As shown in step ST ₁₉ , the control contact 27A turns ON, and the lever 1
At the same time, the restraint of the sun gear 8 by the sun gear 6 is released, and the motor 10 is driven to wind the webbing 3 around the winding shaft 2 (step ST ₂₀ ). Then, when the tension of the webbing 3 increases due to the winding of the webbing 3 by the motor 10, and the torque increases,
The internal gear 20 rotates clockwise in FIG. 1 against the spring force of the coil spring 21, and when the optimum tension is reached for the occupant's body, the control contact 27B is turned ON as shown in step ST ₂₁ , and the control contact 27B is turned on again. The winding is locked (step ST ₂₂ ).

When the tongue is disengaged from the buckle body, the buckle switch 28 is switched from ON to OFF as shown in step ST ₂₃ , and this signal is input to the control circuit 29, thereby causing the lever 16 to restrain the sun gear 8. At the same time as the release, the motor 10 is driven and the webbing 3 is wound up as shown in step _ST24 . As a result, the tension of the webbing 3 gradually increases, and the internal gear 20 rotates clockwise in FIG. contact 27
After passing through C, it contacts the control contact 27D.
However, since the function of this control contact 27D is the same as the function when switching the buckle switch 28 from ON to OFF, it passes through without any change, and then the step
As shown at ST ₂₅ , the control contact 27E is turned on, and the webbing 3 is put into the retracted state and returns to the initial state.

In order to use the webbing 3 again, it is sufficient to repeat the operations from steps _ST1 to _ST25 described above.

According to the embodiment described above, the tension of the webbing 3 is pulled out so that it is smaller when being worn than when being wound up, so that the occupant is not excessively restrained when being worn, and the webbing 3 is wound up by a motor. 1
It can be stably performed by setting the value to 0. Furthermore, since the structure is simpler than conventional ones, it can be downsized and manufactured at low cost.

In addition, in the above-mentioned embodiment, the number of control contacts in each control contact group was three, but this number may be two, or may be four or more by incorporating various functions. .

[Effect of idea]

As explained above, according to the seat belt retractor according to the present invention, the webbing can be retracted reliably by the motor, and the webbing tension when the webbing is attached can be pulled out and the tension when retracted can be lowered. It can be made smaller to improve the feeling of wearing. Moreover, no matter how the occupant moves, the optimal tension can be maintained at all times without giving any uncomfortable pressure. Furthermore, the simple structure allows the device to be made smaller and can be manufactured at low cost.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway schematic side view showing an embodiment of a seat belt retractor according to the present invention;
Fig. 2 is a sectional view taken along the - line in Fig. 1, Fig. 3 is a block diagram showing the control function of the seat belt retractor shown in Figs.
4 is a flowchart showing the operation of the seat belt retractor of FIGS. DESCRIPTION OF SYMBOLS 1... Housing, 2... Winding shaft, 3... Webbing, 4... Disc, 7... Planet gear, 8... Sun gear, 10... Motor, 16... Lever, 19
... Solenoid, 20 ... Internal gear, 21 ... Coil spring, 24 ... Switch body, 26 ... Contact support, 27 ... Control contact, 28 ... Buckle switch, 29 ... Control circuit.

Claims (1)

[Scope of utility model registration request] an arm member fixed to a take-up shaft for winding webbing; a planetary gear rotatably supported by the arm member; a sun gear disposed coaxially with the take-up shaft and meshing with the planet gear; A locking means for preventing rotation of the sun gear, a motor for rotationally driving the sun gear, an internal gear having a switch body and disposed coaxially with the winding shaft and meshing with the planetary gear; a spring member that applies a rotational force in the webbing winding direction to the gear; a buckle switch that is turned ON when the tongue is inserted into the buckle body when the webbing is attached; a first control contact group for detecting the torque applied to the internal gear from the spring member in contact with the switch body of the internal gear in response to rotation; and the first control contact group for detecting the torque applied to the internal gear from the spring member; a second control contact group that detects a torque larger than the control contact group; and when the detected torque of each of the control contact groups is smaller than a predetermined torque, the motor is driven, and when the torque is equal to the predetermined torque, the motor is stopped and the 1. A seat belt retractor comprising a control circuit for activating a locking means for preventing rotation of a sun gear and releasing said locking means when a predetermined torque is exceeded.