Collision detection device

Abstract

To satisfactorily detect whether a collision object in collision with a vehicle is a human.SOLUTION: In a collision detection apparatus 10, a pressure tube 52 is held in a groove part 34 of a tube holding part 32 which constitutes part of the front end part of an absorber 30, and a pressing cover 40 is attached to the front end part of the tube holding part 32. Further, a pressing part 44 of the pressing cover 40 is disposed inside an opening groove part 34B of the groove part 34 and disposed in front of the pressure tube 52. The outer periphery of the pressure tube 52 is provided with a first protrusion part 52A which protrudes forward and faces the pressing part 44 in a front-back direction. The first protrusion part 52A has a pair of upper and lower inclined surfaces 52A1. As viewed from a vehicle width direction, the inclined surfaces 52A1 are inclined in such directions as to come closer to each other as they go forward. Further, the outer periphery of the pressure tube 52 is provided with a second protrusion part 52B. The second protrusion part 52B is disposed above the first protrusion part 52A.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a collision detection device. [Background technology]

[0002] A vehicle has a collision detection sensor mounted on the rear side of the vehicle's bumper cover, which detects whether an object colliding with the vehicle is a person. For example, in a vehicle collision detection sensor mounting structure described in Patent Document 1 below, an impact absorbing member is mounted on the front side of the bumper beam. When viewed from the vehicle width direction, the impact absorbing member is generally formed in a generally concave shape that opens toward the rear. A groove is formed in the front portion of the impact absorbing member, and a pressure tube is held in the groove. In the event of a collision between the vehicle and a person, the impact absorbing member deforms so that the pressure tube is crushed in the vertical direction, thereby detecting a collision between the vehicle and the person. Meanwhile, in the event of a collision between the vehicle and a non-person colliding object, such as a small animal, the upper and lower portions of the impact absorbing member deform, suppressing deformation of the pressure tube. This allows for detection of a collision between the vehicle and a non-person colliding object. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-55711 Summary of the Invention [Problem to be solved by the invention]

[0004] When a vehicle collides with a person facing forward, the vehicle's bumper cover strikes the back of the person's legs. At this time, the person's legs bend from the knees. This reduces the impact load input from the person to the vehicle. This may result in the pressure tube not being crushed properly. In this case, the collision detection device may not be able to properly detect whether the object colliding with the vehicle is a person.

[0005] SUMMARY OF THE INVENTION In consideration of the above, an object of the present invention is to provide a collision detection device that can accurately detect whether an object that has collided with a vehicle is a person. [Means for solving the problem]

[0006] One or more embodiments of the present invention include a bumper beam extending in a vehicle width direction, an absorber disposed adjacent to the front side of the bumper beam and extending in the vehicle width direction, a collision detection sensor including a pressure tube extending in the vehicle width direction and held by the absorber, and outputting a signal according to a pressure change in the pressure tube, a tube holding part that forms a part of a front end of the absorber, that is open to the front side of the vehicle and has a groove that holds the pressure tube rotatably, and a shock absorber that is attached to the front end of the tube holding part and that has a front surface of the tube holding part facing the front of the vehicle. a cover including a main body covering the pressure tube from the side and a pushing portion extending from the main body toward the rear of the vehicle and positioned in front of the pressure tube; a first protrusion provided on the outer periphery of the pressure tube, protruding from the pressure tube toward the front of the vehicle, positioned opposite the pushing portion in the longitudinal direction of the vehicle, and having a pair of upper and lower inclined surfaces that slope in directions approaching each other as they approach the front of the vehicle as viewed in the vehicle width direction; and a second protrusion provided on the outer periphery of the pressure tube or on the inner periphery of the groove, and positioned higher on the vehicle than the first protrusion. [Effects of the Invention]

[0007] According to one or more embodiments of the present invention, it is possible to effectively detect whether an object that has collided with a vehicle is a person. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic plan view showing a collision detection device according to an embodiment of the present invention; [Figure 2] 2 is a cross-sectional view (enlarged cross-sectional view taken along line 2-2 in FIG. 1) of the collision detection device shown in FIG. 1 as seen from the left side. [Figure 3] 3 is an enlarged cross-sectional view showing the periphery of a tube holding portion of the absorber shown in FIG. 2. FIG. [Figure 4] 4 is a cross-sectional view corresponding to FIG. 3, schematically illustrating the operation of the collision detection device in the event of a frontal collision between a vehicle and a person. [Figure 5] 4 is a cross-sectional view corresponding to FIG. 3, schematically illustrating the operation of the collision detection device when a vehicle collides head-on with a collision object other than a person. DETAILED DESCRIPTION OF THE INVENTION

[0009] The collision detection device 10 according to this embodiment will be described below with reference to the drawings. Note that the arrow FR shown as appropriate in the drawings indicates the front side of a vehicle (automobile) V to which the collision detection device 10 is applied, the arrow UP indicates the upper side of the vehicle, and the arrow LH indicates the left side of the vehicle (one side in the vehicle width direction). In the following description, when the up-down, front-rear, and left-right directions are used, they refer to the up-down direction of the vehicle, the front-rear direction of the vehicle, and the left-right direction of the vehicle unless otherwise specified.

[0010] As shown in Figures 1 and 2, the collision detection device 10 is disposed at the front end of the vehicle V and is configured as a device that detects a collision of a collision object with the vehicle V. The collision detection device 10 is configured to include a bumper beam 20 that constitutes a frame member of the vehicle V, an absorber 30 disposed in front of the bumper beam 20, and a push cover 40 that serves as a cover attached to the absorber 30. The collision detection device 10 also has a collision detection sensor 50. Each component of the collision detection device 10 will be described below.

[0011] (About Bumper Beam 20) The bumper beam 20 extends in the left-right direction (vehicle width direction) and is formed into a substantially rectangular closed cross-sectional shape when viewed in a cross section from the longitudinal direction of the bumper beam 20. The bumper beam 20 includes a front panel 22 that forms the front end of the bumper beam 20, and a rear panel 24 that forms the rear of the bumper beam 20.

[0012] The front panel 22 is made of a metal plate, has a thickness in the front-rear direction, and extends in the left-right direction. A recess 22A that is recessed one step toward the rear is formed in the middle of the front panel 22 in the up-down direction. The portion of the front panel 22 above the recess 22A is configured as an upper flange portion 22B, and the portion of the front panel 22 below the recess 22A is configured as a lower flange portion 22C.

[0013] The rear panel 24 is made of a metal plate similar to the front panel 22 and extends in the left-right direction. When viewed in the longitudinal direction, the rear panel 24 is formed in a generally hat shape that is open to the front. The upper end of the rear panel 24 is joined to the upper flange portion 22B of the front panel 22, and the lower end of the rear panel 24 is joined to the lower flange portion 22C of the front panel 22.

[0014] A pair of left and right front side frames 60 that form the framework of the vehicle V are provided on the rear side of the bumper beam 20, and the front side frames 60 extend in the front-to-rear direction. Both ends of the bumper beam 20 in the vehicle width direction are connected to the front ends of the front side frames 60 via crash boxes 62.

[0015] (About Absorber 30) The absorber 30 is made of a foamed resin material, such as urethane foam. The absorber 30 is formed in a generally elongated shape with its longitudinal direction extending in the left-right direction, and is disposed adjacent to the front side of the recessed portion 22A of the bumper beam 20. The absorber 30 is formed in a generally trapezoidal shape in a cross section viewed from the longitudinal direction. Specifically, the lower surface of the absorber 30 slopes downward toward the rear when viewed from the left-right direction. The rear surface of the absorber 30 is fixed to the front surface of the recessed portion 22A of the bumper beam 20. A bumper cover 64 is provided on the front side of the absorber 30. The bumper cover 64 forms the front end of the vehicle V and covers the absorber 30 from the front side.

[0016] As shown in FIG. 3 , the front end of the absorber 30 is provided with a tube holding portion 32 for holding a pressure tube 52 (described later) and for assembling a push cover 40. The tube holding portion 32 protrudes forward from the upper end of the absorber 30. A groove 34, which is open to the front, is formed in the vertically middle portion of the tube holding portion 32 and extends over the entire longitudinal direction of the absorber 30. In a side cross-sectional view from the left, the groove 34 is formed in a generally inverted C shape that is open to the front. Specifically, the groove 34 includes a holding groove 34A that forms the rear portion of the groove 34 and holds the pressure tube 52, and an opening groove 34B that forms the opening of the groove 34. The holding groove 34A is generally elliptical in a side cross-sectional view. The opening groove 34B penetrates in the front-rear direction and communicates with the holding groove 34A. The vertical dimension of the holding groove 34A is set larger than the width (vertical dimension) of the opening groove 34B, and the opening groove 34B extends forward from approximately the vertical center of the holding groove 34A.

[0017] (About the push cover 40) The pushing cover 40 is made of a resin material and is attached to the tube holding portion 32 of the absorber 30. The pushing cover 40 is configured to include a cover main body 42 as a main body portion, and a pushing portion 44.

[0018] The cover body 42 is formed in a generally elongated plate shape extending in the left-right direction and is generally U-shaped and open to the rear in a side cross-sectional view. Specifically, the cover body 42 includes a front wall 42A having a plate thickness direction in the front-to-rear direction, an upper wall 42B extending rearward from the upper end of the front wall 42A, and a lower wall 42C extending rearward from the lower end of the front wall 42A. The cover body 42 is fitted into the tube holding portion 32 from the front side so that the upper wall 42B and the lower wall 42C sandwich the tube holding portion 32 from both vertical sides, thereby assembling the cover body 42 to the tube holding portion 32. When the cover body 42 is assembled to the tube holding portion 32, the front wall 42A is disposed adjacent to the front side of the tube holding portion 32.

[0019] The pressing portion 44 is formed in a generally elongated rib shape with its thickness in the vertical direction and extending in the left-right direction, and extends rearward from the vertical middle portion of the cover main body 42. The thickness dimension of the pressing portion 44 is set smaller than the groove width dimension of the opening groove portion 34B of the absorber 30, and the pressing portion 44 is disposed within the opening groove portion 34B. The rear surface of the pressing portion 44 is configured as a pressing surface 44A, which is curved in an arc shape that convex toward the rear in a side cross-sectional view.

[0020] (Regarding the collision detection sensor 50) The collision detection sensor 50 is composed of a pressure tube 52 held by the absorber 30 and a pressure sensor 54 (broadly speaking, an element that can be understood as a pressure detector) that outputs a signal in response to pressure changes in the pressure tube 52.

[0021] The pressure tube 52 is formed in an elongated shape with its longitudinal direction in the left-right direction and is configured as a hollow structure with a substantially circular cross section. The pressure tube 52 is fitted into the holding groove portion 34A of the groove portion 34 and is rotatably held by the tube holding portion 32 of the absorber 30. The diameter of the pressure tube 52 is set larger than the groove width dimension of the open groove portion 34B.

[0022] A first protrusion 52A is formed on the outer periphery of the front end of the pressure tube 52. The first protrusion 52A is formed in a rib shape extending in the vehicle width direction, and is formed over the entire longitudinal direction of the pressure tube 52. The first protrusion 52A is formed in a substantially triangular shape in a side cross-sectional view. Specifically, the first protrusion 52A has a pair of upper and lower inclined surfaces 52A1, which are inclined in directions approaching each other (inward in the up-down direction) as they extend forward in a side cross-sectional view. The intersection of the pair of inclined surfaces 52A1 forms the front end of the first protrusion 52A, and the first protrusion 52A is disposed within the rear end of the open groove 34B. Specifically, the front end of the first protrusion 52A is positioned adjacent to the rear side of the vertical center of the pressing surface 44A of the pressing portion 44, and the first protrusion 52A and the pressing portion 44 are positioned opposite each other in the front-to-back direction (hereinafter, the position of the pressure tube 52 in this state is referred to as the initial position).

[0023] Furthermore, as will be described in detail later, in the event of a frontal collision between the vehicle and a person, the first protrusion 52A is pressed by the pressing surface 44A of the pressing portion 44, and the pressure tube 52 is arranged to be rotated counterclockwise from the initial position when viewed from the left (the position shown in FIG. 4). On the other hand, in the event of a frontal collision between the vehicle and a colliding object other than a person, the first protrusion 52A is pressed by the pressing surface 44A of the pressing portion 44, and the pressure tube 52 is arranged to be rotated clockwise from the initial position when viewed from the left (the position shown in FIG. 5).

[0024] Furthermore, a second protrusion 52B is formed on the outer periphery of the upper end of the pressure tube 52. The second protrusion 52B is formed in a rib shape extending in the vehicle width direction, and is formed over the entire longitudinal direction of the pressure tube 52. Similar to the first protrusion 52A, the second protrusion 52B is formed in a substantially triangular shape in a side cross section. That is, the second protrusion 52B has a pair of front and rear inclined surfaces 52B1, and the pair of inclined surfaces 52B1 are inclined in directions approaching each other (inward in the front-rear direction) as they extend upward in a side cross section.

[0025] The aforementioned holding groove 34A is formed in a substantially elliptical shape so that the pressure tube 52 can move between the first position and the second position. Specifically, the holding groove 34A is formed in an elliptical shape with its long side in a direction that slopes slightly upward toward the rear (the directions of arrows A and B in FIG. 3 , hereinafter referred to as the slope direction) and its short side in a direction perpendicular to the slope direction (the directions of arrows C and D in FIG. 3 , hereinafter referred to as the orthogonal direction). The pressure tube 52 is disposed within the holding groove 34A such that the inner circumferential surface of the holding groove 34A on one orthogonal direction side (the side along arrow C in FIG. 3 ) contacts the outer circumferential surface of the pressure tube 52, and a gap G is formed between the holding groove 34A and the pressure tube 52. The first protrusion 52A and the second protrusion 52B are disposed in the gap G, and the apex of the second protrusion 52B contacts the inner circumferential surface of the holding groove 34A. In addition, the gap G is formed at least on both the upper and lower sides of the first protrusion portion 52A of the pressure tube 52, preventing the first protrusion portion 52A from interfering with the inner periphery of the retaining groove portion 34A when the pressure tube 52 rotates from its initial position to the first position or the second position.

[0026] The pressure sensors 54 are provided at both longitudinal ends of the pressure tube 52 and are fixed to the vehicle body at positions not shown. The pressure sensors 54 are electrically connected to the ECU 56 (which is broadly understood as a collision determination unit). When the pressure tube 52 deforms, a signal corresponding to the pressure change inside the pressure tube 52 is output from the pressure sensor 54 to the ECU 56.

[0027] Furthermore, the ECU 56 calculates a pressure change value in the pressure tube 52 based on the output signal of the pressure sensor 54, and determines whether the pressure change value exceeds a threshold value to determine whether the object that collided with the bumper cover 64 was a person or an object other than a person, such as a small animal. In more detail, if the pressure change value in the pressure tube 52 is equal to or greater than the threshold value, the ECU 56 determines that the object that collided with the bumper cover 64 is a person, and if the pressure change value in the pressure tube 52 is smaller than the threshold value, the ECU 56 determines that the object that collided with the bumper cover 64 is other than a person.

[0028] (Action and effect) Next, the operation of the collision detection device 10 in the event of a frontal collision between a person and the vehicle V, and in the event of a frontal collision between a collision object other than a person and the vehicle V, will be described, along with the function and effect of this embodiment.

[0029] In a frontal collision of vehicle V with a person, the person's legs strike the bumper cover 64, causing the person to fall onto the hood of vehicle V. Therefore, as shown in FIG. 4 , a rearward, downward collision load F1 is primarily input to the bumper cover 64 and the push cover 40 attached to the front end (tube holding portion 32) of the absorber 30. When the collision load F1 is input to the push cover 40, the push cover 40 assumes a rearward, downward tilt and is displaced rearward. Therefore, the push portion 44 of the push cover 40 tilts rearward within the open groove 34B of the absorber 30. At this time, the push surface 44A of the push portion 44 abuts against the upper inclined surface 52A1 of the first protrusion 52A of the pressure tube 52, pressing the upper inclined surface 52A1 downward. This causes the pressure tube 52 to rotate from the initial position to the first position.

[0030] When the pressure tube 52 is in the first position, the second protrusion 52B of the pressure tube 52 is displaced forward from its initial position, but remains positioned adjacent to and below the upper portion of the tube holding portion 32. Furthermore, as the push cover 40 assumes a rearward tilted posture, the cover body 42 of the push cover 40 primarily presses the upper portion of the tube holding portion 32 diagonally downward and rearward. This causes the upper portion of the tube holding portion 32 to be displaced diagonally upward and rearward, pressing the second protrusion 52B of the pressure tube 52 diagonally downward and rearward. As a result, the pressure tube 52 is deformed as if crushed. This causes a change in pressure within the pressure tube 52, and the pressure sensor 54 outputs a signal corresponding to the pressure change in the pressure tube 52 to the ECU 56. As a result, the ECU 56 detects that the colliding object is a person.

[0031] On the other hand, in a frontal collision between the vehicle V and a non-human object such as a small animal, the impacting object strikes the lower part of the bumper cover 64. Therefore, as shown in FIG. 5 , a collision load F2 acting mainly in the upward and rearward direction is input to the bumper cover 64 and the push cover 40 attached to the front end (tube holding portion 32) of the absorber 30. When the collision load F2 is input to the push cover 40, the push cover 40 assumes a forward tilted position, tilting diagonally downward and forward, and is displaced rearward. Therefore, the push portion 44 of the push cover 40 tilts forward within the opening groove 34B of the absorber 30. At this time, the push surface 44A of the push portion 44 abuts against the lower inclined surface 52A1 of the first protrusion 52A of the pressure tube 52, pressing the lower inclined surface 52A1 upward. This causes the pressure tube 52 to rotate from the initial position to the second position.

[0032] When the pressure tube 52 is in the second position, the second protrusion 52B of the pressure tube 52 is displaced rearward from the initial position, maintaining a state in which the second protrusion 52B is positioned adjacent to the lower side of the upper part of the tube holding portion 32. Furthermore, as the push cover 40 assumes a forward tilted position, the cover body 42 of the push cover 40 presses the lower part of the tube holding portion 32 diagonally upward and rearward. This causes the lower part of the tube holding portion 32 to be displaced diagonally upward and rearward. At this time, the second protrusion 52B of the pressure tube 52 is positioned on the opposite side of the holding groove 34A from the lower part of the tube holding portion 32, thereby preventing the lower part of the tube holding portion 32 from pressing the second protrusion 52B. Furthermore, because a gap G is formed between the pressure tube 52 and the lower part of the tube holding portion 32, even if the lower part of the tube holding portion 32 is displaced diagonally upward and rearward, the lower part of the tube holding portion 32 is prevented from pressing the pressure tube 52. This reduces the change in pressure inside the pressure tube 52 when the vehicle collides with an object other than a human, allowing the ECU 56 to detect that the object colliding with the bumper cover 64 is a small animal or the like other than a human.

[0033] As described above, in the collision detection device 10 of this embodiment, the pressure tube 52 is held in the groove 34 of the tube holding portion 32 that constitutes a part of the front end of the absorber 30, and the push cover 40 is assembled to the front end of the tube holding portion 32. The push portion 44 of the push cover 40 is disposed in the opening groove 34B of the groove 34 and is disposed in front of the pressure tube 52. The outer periphery of the pressure tube 52 is provided with a first protrusion 52A that protrudes forward and faces the push portion 44 in the front-to-rear direction. The outer periphery of the first protrusion 52A is formed with a pair of upper and lower inclined surfaces 52A1, and the inclined surfaces 52A1 are inclined in directions approaching each other as they move forward when viewed in the vehicle width direction. The outer periphery of the pressure tube 52 is provided with a second protrusion 52B that is disposed above the first protrusion 52A. For this reason, as described above, in the event of a frontal collision between the vehicle V and a person, the pushing portion 44 presses the upper inclined surface 52A1 of the first protrusion 52A, thereby rotating the pressure tube 52 from the initial position to the first position. Furthermore, because the second protrusion 52B is disposed higher than the first protrusion 52A, the second protrusion 52B is pressed by the upper portion of the tube holding portion 32 (the upper portion with respect to the groove 34), to which the collision load F1 is mainly input, thereby enabling the pressure tube 52 to be deformed favorably. On the other hand, in the event of a frontal collision between the vehicle V and a colliding object other than a person, the pushing portion 44 presses the lower inclined surface 52A1 of the first protrusion 52A, thereby rotating the pressure tube 52 from the initial position to the second position. Furthermore, at this time, the second protrusion 52B is disposed on the opposite side of the groove 34 from the lower portion of the tube holding portion 32 (the lower portion with respect to the groove 34), thereby enabling the pressure tube 52 to be prevented from being pressed against the second protrusion 52B by the lower portion of the tube holding portion 32. As a result, it is possible to reduce the amount of deformation of the pressure tube 52. Therefore, the collision detection device 10 of this embodiment can effectively detect whether the object that has collided with the vehicle V is a person or not.

[0034] Furthermore, the second protrusion 52B is formed integrally with the pressure tube 52. This allows the holding groove 34A of the absorber 30 to be formed in an elliptical shape, thereby improving the formability of the absorber 30.

[0035] Furthermore, the pushing surface 44A of the pushing portion 44 is curved in an arc shape that protrudes rearward when viewed from the vehicle width direction. Therefore, the pushing surface 44A can press the upper or lower inclined surface 52A1 of the first protrusion 52A, thereby rotating the pressure tube 52 from the initial position to the first position or the second position.

[0036] In this embodiment, the second protrusion 52B is provided on the pressure tube 52, but a protrusion corresponding to the second protrusion 52B may be formed on the inner circumferential surface of the upper part of the retaining groove 34A of the absorber 30 and positioned above the first protrusion 52A. In this case, the protrusion formed on the absorber 30 is positioned adjacent to and in contact with the upper side of the pressure tube 52. In this case, even if the pressure tube 52 is rotated to the first position or the second position, the position of the protrusion corresponding to the second protrusion 52B does not change, so the second protrusion 52B can be easily set to an appropriate position.

[0037] Furthermore, in the present embodiment, the second protrusion 52B is formed in a substantially triangular shape in a side cross-sectional view, but the cross-sectional shape of the second protrusion 52B can be set as desired. For example, the cross-sectional shape of the second protrusion 52B may be formed in a semicircular shape so as to protrude radially outward from the pressure tube 52. In this case, it is possible to reduce the sliding resistance of the second protrusion 52B against the holding groove 34A when the pressure tube 52 rotates within the holding groove 34A. [Explanation of symbols]

[0038] 10 Collision detection device 20 Bumper beam 30 Absorber 32 Tube holding part 34 Groove 40 Push Cover (Cover) 42 Cover body (main body) 44 Pushing part 50 Collision detection sensor 52 Pressure Tube 52A 1st protrusion 52A1 Inclined Surface 52B Second protrusion

Claims

1. a bumper beam extending in the vehicle width direction; an absorber disposed adjacent to the front side of the bumper beam and extending in the vehicle width direction; a collision detection sensor including a pressure tube extending in the vehicle width direction and held by the absorber, the collision detection sensor outputting a signal corresponding to a pressure change in the pressure tube; a tube holding portion that forms a part of a front end portion of the absorber, the tube holding portion being open toward the front side of the vehicle and having a groove that rotatably holds the pressure tube; a cover including: a main body portion that is attached to a front end portion of the tube holding portion and covers a front surface of the tube holding portion from the front side of the vehicle; and a pressing portion that extends from the main body portion toward the rear side of the vehicle and is positioned in front of the pressure tube; a first protrusion provided on an outer periphery of the pressure tube, protruding from the pressure tube toward the front of the vehicle, and disposed opposite the pushing portion in the vehicle longitudinal direction, the first protrusion having a pair of upper and lower inclined surfaces that are inclined in directions approaching each other as they approach the front of the vehicle as viewed in the vehicle width direction; a second protrusion provided on an outer circumferential portion of the pressure tube or an inner circumferential portion of the groove, the second protrusion being positioned higher on the vehicle than the first protrusion; A collision detection device comprising:

2. 2. The collision detection device according to claim 1, wherein the second protrusion protrudes upward from an outer periphery at the upper end of the pressure tube.

3. 3. The collision detection device according to claim 1, wherein the rear end surface of the pushing portion is curved in an arc shape that is convex toward the rear of the vehicle when viewed in the vehicle width direction.

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