JPH023180Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an acceleration sensor applicable to a vehicle seat belt device.

[Background Art] A vehicle seat belt device is equipped with an acceleration sensor, and when the vehicle acceleration reaches a predetermined value, rolling elements roll on the installation platform and push up a pole, which engages with a ratchet foil, etc. Accordingly, the webbing is prevented from being pulled out.

This allows the occupant to freely pull out the webbing for normal use of the vehicle and change the driving position, and in the event of an emergency, the occupant is prevented from pulling out the webbing to ensure a secure restraint.

By the way, when a vehicle is traveling on a rough road, the vibrations of the vehicle cause the rolling elements to repeat minute vibrations, which causes the pole to be continuously pushed up, similar to when a large acceleration is applied. This condition may continue. As a result, the occupant restraint webbing is prevented from being pulled out, causing a feeling of discomfort for the occupant to wear the webbing.

[Purpose of the invention] Taking the above-mentioned facts into consideration, the object of the present invention is to obtain an acceleration sensor that suppresses minute vibrations of rolling elements when a vehicle runs on a rough road, etc., and enables an appropriate acceleration response.

[Structure of the invention] In the acceleration sensor according to the invention, an elastic protrusion is integrally erected from the installation base, and this elastic protrusion is inserted into a receiving recess formed at the bottom of the rolling element on the installation base. The deformation of this elastic protrusion generates a return force to the rolling element to damp vibrations when the rolling element vibrates, and an intermediate push-up part is provided on the upper part of the rolling element. At the same time, the center upper part is connected to the pole and lateral movement is restricted, so when the rolling elements roll, the other rotates around one side of the periphery and separates from the rolling element. Even when the rolling directions of the rollers are different, a uniform and sufficient push-up stroke can be obtained.

[Embodiment of the invention] FIG. 1 shows an acceleration sensor according to a first embodiment of the invention. An installation base 10 made of synthetic resin has a conical recess 12 formed on its upper surface. An elastic protrusion 14 integrally projects from the center of the conical recess 12, that is, from the deepest point of the cone. This elastic protrusion 14 has a rod shape with a vertical axis.

A rolling element 16 is placed on the installation stand 10. This rolling element 16 is provided with a spherical part 18 made of synthetic resin at its lower end, and the surface of this spherical part 18 is in contact with the conical recess 12 . Therefore, even if the spherical part 18 rolls, little noise is generated between it and the synthetic resin installation base 10. A receiving recess 20 coaxial with the elastic protrusion 14 is formed in the center of the spherical part 18, into which the elastic protrusion 14 is inserted. This receiving recess 20 has a conical shape in this embodiment, and is spaced apart from or lightly in contact with the elastic protrusion 14 when the rolling element 16 is in a vertical state. However, when the rolling element 16 rolls on the conical recess 12 as shown in FIG. 2, it contacts the elastic protrusion 14 and elastically deforms the elastic protrusion 14.

A cylindrical portion 22 is integrally erected at the upper center of the spherical portion 18, and a weight 24 is arranged around the cylindrical portion 22. That is, the weight 24 has a cylindrical shape, the cylindrical part 22 is inserted into the hollow part of the axis, and the top plate 26 is placed on the top of the weight 24. After passing through the top plate 26, the cylindrical part 22 is thermally deformed to fix the top plate 26 and the weight 24 to the spherical part 18. The weight 24 is made of metal, and the rolling element 1
6, the weight 24 controls the center of gravity of the rolling element 16.
By being arranged relatively above the rolling element 1
6 is in a state where it is easy to roll.

A standing wall 26A is formed around the top plate 26, and accommodates the periphery of the intermediate push-up member 28 onto the top plate 26. That is, the intermediate push-up member 28 is in the shape of an upside-down dish, and the vicinity of the outer periphery, which is the lower end, is placed on the top plate 26, and its movement in the left-right direction is restricted by the vertical wall 26A.

A stepped pin 3 is inserted from the upper center of the intermediate push-up member 28.
0 protrudes, and the small diameter portion 30A of the stepped pin 30 is inserted into the circular hole 3 formed in the intermediate portion of the pole 32.
It is inserted into 4. The base of this pole 32 is pivotally supported by a pin 36 to a bracket 38 by a pin 39, and the bracket 38 is integrally connected to the installation base 10. Therefore, although the central upper part of the intermediate push-up member 28 is rotatable together with the pawl 32 about the pin 39, movement in the left and right lateral directions is restricted.

The tip of this pawl 32 corresponds to a ratchet wheel (not shown), and has a structure in which rotation of the ratchet wheel can be stopped when the pawl 32 is pushed up by the rolling elements 16 and engages with the ratchet wheel. The ratchet wheel is directly or indirectly connected to the take-up shaft of the occupant restraint webbing, and when the ratchet wheel stops, the rotation of the webbing is stopped.

The operation of this embodiment configured in this way will be explained. FIG. 1 shows the vehicle in a normal state in which the axes of the rolling elements 16 are vertical. In this state, the pawl 32 is separated from the ratchet wheel (not shown), so the occupant restraint webbing can be pulled out, and the occupant can pull out the webbing and assume any driving position.

In an emergency situation such as a vehicle collision, the rolling elements 16 detect vehicle acceleration (acting in the horizontal direction in FIG. 1) and roll on the conical recess 12. Stepped pin 30
is connected to the pole 32, so that the small diameter portion 3
As shown in FIG. 2, the intermediate push-up member 28, whose lateral movement is restricted at the 0A portion, comes into contact with the top plate 26 of the rolling element 16 at one point on its periphery and receives a push-up force. This pushing up force pushes the pole 32 to the pin 3
6 and the tip of the pole 32 rises.
Therefore, the tip of the pawl 32 engages with a ratchet wheel (not shown) to stop the rotation. As a result, the occupant restraining webbing is prevented from being pulled out, and the occupant is placed in a restrained state.

The intermediate push-up member 28 has a uniform push-up stroke because the stepped pin 30 has a uniform push-up stroke even when the rolling element 16 rolls in either direction, that is, even when horizontal acceleration is applied in any direction. The pawl 32 can engage with the ratchet foil under the following conditions. Moreover, the intermediate push-up member 28
Since the other side rotates around one side in contact with 6, the push-up stroke can be increased compared to the case where it moves vertically, and even if the rolling angle of the rolling element 16 is limited by the elastic protrusion 14, this covers it and is sufficient. A push-up stroke can be obtained.

Furthermore, even though the vehicle is not in an emergency situation, when driving on a rough road with many bumps, minute vibrations may cause the rolling elements 16 to
added to. As a result, the rolling elements 16 are subjected to minute accelerations in the vertical and horizontal directions. When this acceleration reaches a predetermined frequency, the rolling elements 16 may move laterally on the conical recess 12 or perform circular motion around the vertical axis.
This may result in behavior similar to when a large acceleration is applied.

During such vibration, the rolling elements 16 elastically deform the elastic protrusions 14, similar to the state shown in FIG. Therefore, the elastic protrusion 14 has the power to return the energy generated by its elastic deformation to the direction in which the axis of the rolling element 16 is perpendicular. As a result, the vibration damping of the rolling element 16 becomes faster, and the rolling element 16 quickly returns to its normal state. Therefore, even when the vehicle travels on a rough road, the occupant can maintain a comfortable driving posture.

Next, FIG. 3 shows an acceleration sensor according to a second embodiment of the present invention.

In this embodiment, a columnar section 40 made of synthetic resin is formed in place of the spherical section 18 of the previous embodiment. The columnar part 40 has a tapered lower end and a lower end surface that is a horizontal plane perpendicular to the axis.
It is inserted into a flat recess 42 formed at 0. An elastic protrusion 14 similar to that of the previous embodiment projects from this flat recess 42 and is inserted into a receiving recess 20 formed on the bottom surface of the columnar part 40.

Therefore, in this embodiment as well, the rolling elements 16 roll on the installation base 10 when the horizontal acceleration reaches a predetermined value, but when rolling, they roll around the columnar part 40 as a fulcrum, so that the rolling start acceleration is Clear boundary values can be set.

Next, FIG. 4 shows an acceleration sensor according to a third embodiment of the present invention. In this embodiment, the upper shape of the rolling element 16 is different from that in the first embodiment.

That is, the outer circumferential portion of the spherical portion 18 is further extended to the outer circumference to form a plate portion 44, and this plate portion 44 serves as a surrounding mounting surface for the intermediate push-up member 28 and is erected from the outer circumferential portion of the plate portion 44. The vertical wall 44A restrains the intermediate push-up member 28 from moving in the lateral direction.

Therefore, in this embodiment, the same effects as in each of the above-mentioned embodiments can be obtained, but in particular, in this embodiment, the leverage for pushing up the pawl 32 when the rolling element 16 rolls can be increased, A large push-up stroke can be obtained.

[Effects of the invention] As explained above, in the acceleration sensor according to the invention, the elastic protrusion erected from the installation base is inserted into the receiving recess formed at the bottom of the rolling element to damp vibration when the rolling element vibrates. Appropriate acceleration response is possible, and an intermediate push-up member is provided above the rolling element, the periphery of which is placed on the rolling element, and the upper center of which is connected to the pole and whose lateral movement is restrained. Even when horizontal acceleration is applied, a uniform and sufficient push-up stroke can be obtained.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing an acceleration sensor according to a first embodiment of the present invention, FIG. 2 is an operation diagram of FIG. 1, and FIG. 3 is a longitudinal sectional view showing a second embodiment of the present invention. 4
The figure is a longitudinal sectional view showing a third embodiment of the present invention. 10... Installation stand, 12... Conical recess, 14...
...Elastic protrusion, 16...Rolling element, 20...Receiving recess, 28...Intermediate push-up member, 30...Stepped pin,
32...pole, 34...round hole.

Claims (1)

[Scope of utility model registration request] Place the rolling element on the installation stand, and insert the elastic protrusion integrally erected from the installation stand into the receiving recess formed at the bottom of the rolling element to damp vibration when the rolling element vibrates. The periphery is placed on the rolling element, and the upper center is the connection part with the pole, which restricts lateral movement.When the rolling element rolls, one side of the periphery contacts the rolling element, and the other rotates around this one. An acceleration sensor characterized in that an intermediate push-up member is provided that moves away from the rolling element.