U.S. patent application number 15/233491 was filed with the patent office on 2017-03-02 for vehicle pop-up hood device actuator and vehicle pop-up hood device.
This patent application is currently assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA. The applicant listed for this patent is TOYOTA JIDOSHA KABUSHIKI KAISHA. Invention is credited to Joji AOYAMA, Sotaro NARITA.
Application Number | 20170057457 15/233491 |
Document ID | / |
Family ID | 56799302 |
Filed Date | 2017-03-02 |
United States Patent
Application |
20170057457 |
Kind Code |
A1 |
NARITA; Sotaro ; et
al. |
March 2, 2017 |
VEHICLE POP-UP HOOD DEVICE ACTUATOR AND VEHICLE POP-UP HOOD
DEVICE
Abstract
A vehicle pop-up hood device actuator includes a main body
section; a cylinder that covers a portion on one axial direction
side of the main body section, that is moved toward the one axial
direction side of the main body section by generated gas to lift a
hood of a vehicle to a lifted position, and that is configured so
as to be capable of moving to a retention position; a sealing
member that is formed in a ring shape and that forms a seal between
the main body section and a general face; a retention member that
abuts on an inner peripheral face of the cylinder and retains the
cylinder at the retention position; and an enlarged diameter face
that is disposed at a radial direction outer side of the main body
section with respect to the sealing member at the lifted
position.
Inventors: |
NARITA; Sotaro; (Toyota-shi,
JP) ; AOYAMA; Joji; (Kiyosu-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TOYOTA JIDOSHA KABUSHIKI KAISHA |
Toyota-shi |
|
JP |
|
|
Assignee: |
TOYOTA JIDOSHA KABUSHIKI
KAISHA
Toyota-shi
JP
|
Family ID: |
56799302 |
Appl. No.: |
15/233491 |
Filed: |
August 10, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F42B 3/04 20130101; F15B
15/1438 20130101; B60R 21/38 20130101; B60R 21/26 20130101; B60R
21/264 20130101; C06D 5/00 20130101 |
International
Class: |
B60R 21/38 20060101
B60R021/38 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 26, 2015 |
JP |
2015-167109 |
Claims
1. A vehicle pop-up hood device actuator, comprising: a main body
section that is formed in a tube shape, and that internally
includes a gas generator; a cylinder that is formed in a bottomed
tube shape closed off at one axial direction side, that has an
inner peripheral face at the one axial direction side configuring a
general face, that covers a portion at the one axial direction side
of the main body section, that is moved toward the one axial
direction side of the main body section by gas generated by the gas
generator to lift a hood of a vehicle to a lifted position, and
that is configured so as to be capable of moving to a retention
position further toward another axial direction side of the main
body section than the lifted position; a sealing member that is
formed in a ring shape, that is provided at an outer peripheral
portion at one axial direction end portion of the main body
section, and that forms a seal between the main body section and
the general face; a retention member that is provided at the outer
peripheral portion of the main body section at a position further
toward the another axial direction side of the main body section
than the sealing member, that abuts on the inner peripheral face of
the cylinder, and that retains the cylinder by engaging with the
cylinder at the retention position; and an enlarged diameter face
that configures an inner peripheral face at the another axial
direction side of the cylinder, that has an internal diameter set
larger than both an internal diameter of the general face and an
external diameter of the sealing member, and that is disposed at a
radial direction outer side of the main body section with respect
to the sealing member at the lifted position.
2. The vehicle pop-up hood device actuator of claim 1, wherein a
boundary portion between the enlarged diameter face and the general
face at the inner peripheral face of the cylinder configures an
inclined face, and the inclined face is inclined toward the one
axial direction side on progression toward a radial direction inner
side of the cylinder as viewed in vertical cross-section.
3. The vehicle pop-up hood device actuator of claim 2, wherein the
inclined face engages with the retention member at the retention
position.
4. A vehicle pop-up hood device, comprising: the vehicle pop-up
hood device actuator of claim 1, provided at a lower side of a hood
of a vehicle; and a controller that is electrically connected to
the vehicle pop-up hood device actuator, and that actuates the
vehicle pop-up hood device actuator.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority under 35 USC 119 from
Japanese Patent Application No. 2015-167109 filed Aug. 26, 2015,
the disclosure of which is incorporated by reference herein.
BACKGROUND
[0002] Technical Field
[0003] Technology disclosed herein relates to a vehicle pop-up hood
device actuator that lifts a vehicle hood, and to a vehicle pop-up
hood device.
[0004] Related Art
[0005] Japanese Patent Application Laid-Open (JP-A) No. 2013-71544
describes what is known as a piston cylinder type actuator that
lifts a vehicle hood. Specifically, the actuator is configured
including a tube shaped cylinder, and a piston rod housed inside
the cylinder. A piston portion of the piston rod is provided with a
lock pin. When a gas generator provided in the cylinder is
actuated, the piston rod rises with respect to the cylinder by the
gas generated by the gas generator, thereby lifting the vehicle
hood. When this is performed, the lock pin anchors to an anchor
face of the cylinder, and the piston rod is retained by the lock
pin. The lifting of the hood is thereby retained, protecting a
pedestrian falling onto the hood. Note that an actuator that lifts
a vehicle hood is also described in JP-A No. 2014-133535.
[0006] If high pressure gas remains inside the cylinder after
actuation of the actuator, a reaction force from the hood acting on
the pedestrian falling onto the hood could increase, thereby
raising the pedestrian injury criteria. Forming gas escape holes in
the cylinder to release high pressure gas inside the cylinder, for
example, may be considered in order to reduce the reaction force on
the pedestrian from the hood.
[0007] However, when gas escape holes are formed in the cylinder,
there is a possibility of a lock pin catching on the peripheries of
openings of the gas escape holes when the piston rod rises with
respect to the cylinder during actuation of the actuator. There is
accordingly a need for high assembly precision of the actuator in
order to prevent the lock pin from catching on the peripheries of
the openings of the gas escape holes. In other words, it is
desirable for the actuator have a structure in which the effect of
assembly precision on actuation is suppressed.
[0008] An exemplary embodiment of the present invention provides a
vehicle pop-up hood device actuator and a vehicle pop-up hood
device capable of lowering pedestrian injury criteria, while
suppressing the effect of assembly precision on actuation.
SUMMARY
[0009] A vehicle pop-up hood device actuator according to a first
aspect of the present invention includes: a main body section that
is formed in a tube shape, and that internally includes a gas
generator; a cylinder that is formed in a bottomed tube shape
closed off at one axial direction side, that has an inner
peripheral face at the one axial direction side configuring a
general face, that covers a portion at the one axial direction side
of the main body section, that is moved toward the one axial
direction side of the main body section by gas generated by the gas
generator to lift a hood of a vehicle to a lifted position, and
that is configured so as to be capable of moving to a retention
position further toward another axial direction side of the main
body section than the lifted position; a sealing member that is
formed in a ring shape, that is provided at an outer peripheral
portion at one axial direction end portion of the main body
section, and that forms a seal between the main body section and
the general face; a retention member that is provided at the outer
peripheral portion of the main body section at a position further
toward the another axial direction side of the main body section
than the sealing member, that abuts on the inner peripheral face of
the cylinder, and that retains the cylinder by engaging with the
cylinder at the retention position; and an enlarged diameter face
that configures an inner peripheral face at the another axial
direction side of the cylinder, that has an internal diameter set
larger than both an internal diameter of the general face and an
external diameter of the sealing member, and that is disposed at a
radial direction outer side of the main body section with respect
to the sealing member at the lifted position.
[0010] In the vehicle pop-up hood device actuator (referred to
below as the "actuator") configured as described above, the
actuator is configured including the main body section and the
cylinder. The main body section is formed in a tube shape, and the
gas generator is provided inside the main body section. The
cylinder is formed in a bottomed tube shape closed off at the one
axial direction side, and the inner peripheral face at the one
axial direction side of the cylinder configures the general face.
The portion at the one axial direction side of the main body
section is covered by the cylinder.
[0011] The sealing member that is formed in a ring shape is
provided at the outer peripheral portion at the one axial direction
end portion of the main body section. The sealing member forms a
seal between the main body section and the general face of the
cylinder. Moreover, the retention member is provided at the outer
peripheral portion of the main body section at a position further
toward the another axial direction side of the main body section
than the sealing member, and the retention member abuts on the
inner peripheral face of the cylinder. Accordingly, when the
cylinder is moved in the axial direction of the main body section,
frictional force arises between the retention member and the
cylinder. When the gas generator is actuated, the cylinder is moved
toward the one axial direction side of the main body section by the
generated gas, and the hood of the vehicle is lifted to the lifted
position. When the cylinder is moved to the retention position
further toward the another axial direction side of the main body
section than the lifted position, the retention member engages with
the cylinder, whereby the cylinder is retained by the retention
member.
[0012] Note that the inner peripheral face on an opening end side
of the cylinder is configured by the enlarged diameter face. The
internal diameter of the enlarged diameter face is set larger than
both the internal diameter of the general face and the external
diameter of the sealing member. At the lifted position, the
enlarged diameter face is disposed at the radial direction outer
side of the main body section with respect to the sealing member.
Gas inside the cylinder accordingly flows out from between the
enlarged diameter face and the sealing member toward the opening
side of the cylinder. This thereby enables gas inside the cylinder
to escape without forming gas escape holes in the cylinder. The
effect of the assembly precision of the actuator on actuation of
the actuator can accordingly be suppressed in comparison to
configurations in which gas escape holes are formed in the
cylinder.
[0013] At the lifted position, the gas inside the cylinder escapes,
thereby enabling high pressure gas to be suppressed from remaining
inside the cylinder. This thereby enables a reaction force from the
hood on the pedestrian falling onto the hood to be reduced. The
cylinder is moved from the lifted position to the retention
position, against the frictional force between the retention member
and the cylinder, when a specific load toward the vehicle lower
side from the pedestrian falling onto the hood acts on the
cylinder. This thereby enables collision energy to the pedestrian
to be absorbed by the frictional force between the retention member
and the cylinder. The pedestrian injury criteria can accordingly be
lowered.
[0014] A vehicle pop-up hood device actuator according to a second
aspect of the present invention is the vehicle pop-up hood device
actuator according to the first aspect of the present invention,
wherein a boundary portion between the enlarged diameter face and
the general face at the inner peripheral face of the cylinder
configures an inclined face, and the inclined face is inclined
toward the one axial direction side on progression toward a radial
direction inner side of the cylinder as viewed in vertical
cross-section.
[0015] In the actuator configured as described above, the inclined
face configuring the boundary portion between the enlarged diameter
face and the general face is inclined toward the one axial
direction side on progression toward the radial direction inner
side of the cylinder as viewed in vertical cross-section. This
thereby enables the sealing member and the retention member to be
suppressed from catching on the inclined face in comparison to
cases in which, for example, an inclined face is formed along a
direction orthogonal to the axial direction of the cylinder as
viewed in vertical cross-section. This thereby enables damage to
the sealing member and the retention member to be suppressed,
thereby enabling the reliability of the actuator to be
improved.
[0016] A vehicle pop-up hood device actuator according to a third
aspect of the present invention is the vehicle pop-up hood device
actuator according to the second aspect of the present invention,
wherein the inclined face engages with the retention member at the
retention position.
[0017] The actuator configured as described above enables the
inclined face of the enlarged diameter portion to be utilized in
the engagement of the cylinder with the retention member so as to
retain the cylinder at the retention position.
[0018] A vehicle pop-up hood device according to a fourth aspect of
the present invention includes the vehicle pop-up hood device
actuator of any one of the first aspect to the third aspect of the
present invention, provided at a lower side of a hood of a vehicle,
and a controller that is electrically connected to the vehicle
pop-up hood device actuator, and that actuates the vehicle pop-up
hood device actuator.
[0019] The vehicle pop-up hood device configured as described above
enables good lifting of the hood to the lifted position by the
actuator, and also enables collision energy to a pedestrian to be
absorbed.
[0020] As described above, the vehicle pop-up hood device actuator
of the present disclosure is capable of lowering pedestrian injury
criteria, while suppressing the effect of assembly precision on
actuation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Exemplary embodiments of the present invention will be
described in detail based on the following figures, wherein:
[0022] FIG. 1A is a vertical cross-section illustrating the inside
of a front actuator according to an exemplary embodiment,
illustrating a non-actuated state of the front actuator;
[0023] FIG. 1B is a vertical cross-section illustrating the inside
of a front actuator according to the present exemplary embodiment,
illustrating a state of the front actuator after actuation;
[0024] FIG. 2 is a plan view illustrating an overall configuration
of a vehicle pop-up hood device applied with a front actuator
according to the present exemplary embodiment;
[0025] FIG. 3 is a side view illustrating an enlargement of a rear
pop-up hood device disposed on the right side of the vehicle
illustrated in FIG. 2, as viewed from a vehicle width direction
central side;
[0026] FIG. 4 is a side view illustrating an actuated state of a
pop-up mechanism section illustrated in FIG. 3, as viewed from the
vehicle width direction central side;
[0027] FIG. 5 is a front view schematically illustrating a front
pop-up hood device illustrated in FIG. 2, as viewed from a vehicle
front side;
[0028] FIG. 6 is a front view illustrating an enlargement of a hood
lock device illustrated in FIG. 5;
[0029] FIG. 7 is a side cross-section schematically illustrating a
state in which an engine room is closed off by a hood illustrated
in FIG. 2, as viewed from a vehicle left side;
[0030] FIG. 8A is a vertical cross-section illustrating an
enlargement of relevant portions of the front actuator illustrated
in FIG. 1A;
[0031] FIG. 8B is a vertical cross-section illustrating a state
immediately prior to releasing gas inside a cylinder after
actuation of the front actuator;
[0032] FIG. 9A is a vertical cross-section illustrating a state in
which a cylinder of the front actuator is disposed at a lifted
position and gas is escaping from inside the cylinder;
[0033] FIG. 9B is a vertical cross-section illustrating a state in
which the cylinder has retracted from the state in FIG. 9A with
respect to an actuator main body and is retained at a retention
position;
[0034] FIG. 10 is a perspective view illustrating a state in which
a pedestrian falling onto the hood of the vehicle illustrated in
FIG. 2 is lifted up together with the hood by a vehicle pop-up hood
device, as viewed from a vehicle oblique-left front side; and
[0035] FIG. 11 is an explanatory diagram to explain the front
actuator illustrated in FIG. 8B alongside a comparative
example.
DETAILED DESCRIPTION
[0036] Explanation follows regarding a vehicle pop-up hood device
30 (referred to below as the "PUH device 30") applied with a front
side actuator 110 serving as "a vehicle pop-up hood device
actuator" according to an exemplary embodiment, with reference to
the drawings. Note that in the drawings, the arrow FR indicates a
vehicle front direction, the arrow UP indicates a vehicle upward
direction, and the arrow RH indicates a vehicle right direction of
a vehicle (automobile) V applied with the PUH device 30, as
appropriate. In the following explanation, unless specifically
stated otherwise, reference simply to the front and rear, up and
down, and left and right directions indicates front and rear in a
vehicle front-rear direction, up and down in a vehicle up-down
direction, and left and right in a vehicle left-right direction
(vehicle width direction).
[0037] As illustrated in FIG. 2, the PUH device 30 is configured
including rear pop-up hood devices 40 (referred to below as the
"rear PUH devices 40") that lift a rear end section of a hood 10
provided at a front section of the vehicle V, and a front pop-up
hood device 80 (referred to below as the "front PUH device 80")
that lifts a front end section of the hood 10. The PUH device 30
further includes an ECU 140, this being an example of a
"controller" according to technology disclosed herein, that
actuates the rear PUH devices 40 and the front PUH device 80. In
the event of a collision between the vehicle V and a pedestrian P,
the hood 10 is lifted (popped up) by the PUH device 30 (see FIG.
10). First, explanation is given regarding the hood 10, followed by
explanation regarding the rear PUH devices 40, the front PUH device
80, and the ECU 140.
[0038] Hood 10
[0039] The hood 10 is formed in a substantially rectangular shape
in plan view, and covers an engine room (power unit compartment) ER
provided at the front section of the vehicle V from an upper side.
As illustrated in FIG. 7, the hood 10 is configured including a
hood outer panel 12 and a hood inner panel 14. The hood outer panel
12 configures a portion on the vehicle outer side of the hood 10
(on the opposite side to the engine room ER), and configures a
design face of the vehicle V. The hood inner panel 14 configures a
portion on the engine room ER side of the hood 10. A terminal
portion of the hood inner panel 14 is joined to a terminal portion
of the hood outer panel 12 by hemming (see FIG. 3).
[0040] A hood striker 16 is provided at a vehicle width direction
intermediate portion of the front end section of the hood 10. The
hood striker 16 projects out from the hood 10 toward a lower side.
As viewed from the side, the hood striker 16 is formed
substantially in a U-shape opening toward the upper side, and an
open end portion of the hood striker 16 is joined to the hood 10. A
lower end portion of the hood striker 16 configures an anchor
portion 16A. The anchor portion 16A extends in the front-rear
direction. In a state in which the engine room ER is closed off by
the hood 10 (the position illustrated by solid lines in FIG. 7;
this position is referred to below as the "closed position"), the
hood striker 16 is anchored to a hood lock device 82 of the front
PUH device 80, described later. The front end section of the hood
10 is thereby fixed to the vehicle body.
[0041] As illustrated in FIG. 3, a protruding portion 14A is formed
at a rear end side (rear section side) of the hood inner panel 14.
The protruding portion 14A protrudes to the lower side of the hood
inner panel 14, and a bottom wall 14A1 of the protruding portion
14A is disposed substantially parallel to the hood outer panel 12
as viewed in side cross-section.
[0042] Rear PUH Device 40
[0043] As illustrated in FIG. 2, the rear PUH devices 40 are
respectively installed at both vehicle width direction end portions
of the rear end section of the hood 10. The pair of left and right
rear PUH devices 40 are configured with left-right symmetry to each
other. Accordingly, explanation follows regarding the rear PUH
device 40 disposed on the right side, and explanation regarding the
rear PUH device 40 disposed on the left side is omitted.
[0044] As illustrated in FIG. 3 and FIG. 4, the rear PUH device 40
is configured including a hood hinge 44 that supports the hood 10
so as to be capable of opening and closing, and a rear side
actuator 70 that actuates in the event of a collision with a
collision body such as the pedestrian P (see FIG. 10).
[0045] Hood Hinge 44
[0046] The hood hinge 44 is configured including a hinge base 46
that is fixed to the vehicle body, a first arm 48 that is coupled
to the hinge base 46 so as to be capable of swinging, and a second
arm 54 that is fixed to the hood 10.
[0047] The hinge base 46 is formed substantially in an inverted
L-shaped plate shape as viewed from the front of the vehicle, and
is formed substantially in a V-shape opening toward the oblique
upper front in side view as viewed from the vehicle width direction
inner side (see FIG. 4 for more detail). Specifically, the hinge
base 46 is configured including an attachment portion 46A with a
plate thickness direction in the up-down direction, and a support
portion 46B extending from a vehicle width direction inner side end
portion of the attachment portion 46A toward the upper side. The
attachment portion 46A is fixed to an upper face portion 20A of a
cowl top side 20, this being a vehicle body side configuration
member. Note that the cowl top sides 20 are provided on both sides
of a cowl that extends along the vehicle width direction between a
rear end side of the hood 10 and a lower end portion of a
windshield glass WG.
[0048] The first arm 48 is disposed at the vehicle width direction
inner side of the hinge base 46, and is formed substantially in an
inverted triangular plate shape as viewed from the side.
Specifically, as viewed from the side, the first arm 48 is formed
substantially in an inverted triangular plate shape having vertices
at a lower end portion 48A, a front end portion 48B disposed at a
front side and upper side of the lower end portion 48A, and a rear
end portion 48C disposed at a rear side and upper side of the lower
end portion 48A.
[0049] A first hinge pin 50 with an axial direction in the vehicle
width direction couples the rear end portion 48C of the first arm
48 to an upper end portion of the support portion 46B of the hinge
base 46, so as to be capable of swinging. The first arm 48 is
thereby configured so as to be capable of swinging relative to the
hinge base 46 about the first hinge pin 50 (in the arrow A
direction and the arrow B direction in FIG. 3). Moreover, the lower
end portion 48A of the first arm 48 is provided with a first
coupling shaft 52 that supports a lower end portion of the rear
side actuator 70, described later. The first coupling shaft 52 is
formed in a substantially circular column shape, and projects out
from the first arm 48 toward the vehicle width direction inner
side, with an axial direction in the vehicle width direction.
[0050] The second arm 54 is disposed at the vehicle width direction
inner side of the first arm 48, and extends substantially along the
front-rear direction. Specifically, the second arm 54 includes a
side wall portion 54A disposed substantially parallel to the first
arm 48. A second hinge pin 56 with an axial direction in the
vehicle width direction couples a front end portion of the side
wall portion 54A to the front end portion 48B of the first arm 48,
so as to be capable of swinging. The second arm 54 is thereby
configured so as to be capable of swinging relative to the first
arm 48 about the second hinge pin 56 (in the arrow C direction and
the arrow D direction in FIG. 3).
[0051] The second arm 54 includes a top wall portion 54B. The top
wall portion 54B is bent from an upper end portion of the side wall
portion 54A toward the vehicle width direction inner side, and
extends substantially in the front-rear direction along the bottom
wall 14A1 of the protruding portion 14A of the hood 10. The top
wall portion 54B is penetrated by an attachment hole, not
illustrated in the drawings, and a weld nut (not illustrated in the
drawings) is fixed to the bottom wall 14A1 of the protruding
portion 14A so as to correspond to the attachment hole. A hinge
bolt, not illustrated in the drawings, is inserted into the
attachment hole from the lower side and screwed together with the
weld nut, thereby fastening (fixing) the top wall portion 54B to
the hood 10.
[0052] The rear end section of the hood 10 is thereby coupled to
the vehicle body by the hood hinge 44. A shear pin 58 projecting
out toward the vehicle width direction outer side is provided at
the side wall portion 54A of the second arm 54, and the second arm
54 is joined to the first arm 48 by the shear pin 58. Accordingly,
in a non-actuated state of the rear side actuator 70, described
later, the hood 10 opens up and closes off the engine room ER by
the second arm 54 and the first arm 48 swinging about the first
hinge pin 50.
[0053] Moreover, a rear end portion of the side wall portion 54A of
the second arm 54 is integrally provided with a second coupling
shaft 60 for coupling a cylinder 76 of the rear side actuator 70,
described later. The second coupling shaft 60 is formed in a
substantially circular column shape, and projects out from the side
wall portion 54A toward the vehicle width direction inner side.
[0054] Rear Side Actuator 70
[0055] As illustrated in FIG. 3, the rear side actuator 70 is
disposed at the vehicle width direction inner side of the first arm
48, and extends so as to span between the rear end portion of the
side wall portion 54A and the lower end portion 48A of the first
arm 48. Specifically, the rear side actuator 70 is inclined toward
the rear side on progression toward the upper side as viewed from
the side. Moreover, the rear side actuator 70 includes an actuator
main body 72 and the cylinder 76.
[0056] The actuator main body 72 is formed in a substantially
circular tube shape open at an upper end side. A lower end portion
of the actuator main body 72 is swingably supported by the first
coupling shaft 52 of the first arm 48. The lower end portion of the
rear side actuator 70 is thereby configured capable of swinging
relative to the first arm 48.
[0057] A gas generator 74 is provided inside the actuator main body
72. The gas generator 74 is formed in a substantially circular
column shape, and is fitted inside the actuator main body 72. The
gas generator 74 includes a squib (ignition device), and the inside
of the gas generator 74 is filled with a gas generating agent. The
gas generator 74 is electrically connected to the ECU 140 (see FIG.
2), described later, and configuration is made such that the gas
generator 74 is actuated under the control of the ECU 140. When the
gas generator 74 is actuated, the squib generates heat and the gas
generating agent combusts, thereby supplying gas generated by the
gas generator 74 into the actuator main body 72.
[0058] The cylinder 76 is formed substantially in a bottomed,
circular tube shape. A portion on one axial direction side of the
actuator main body 72 is housed inside the cylinder 76, and the
cylinder 76 is configured so as to be capable of moving relative to
the actuator main body 72 in the axial direction of the actuator
main body 72. Note that an 0-ring or the like, not illustrated in
the drawings, forms a seal between the cylinder 76 and the actuator
main body 72.
[0059] A cylinder coupling portion 78 is integrally provided at an
upper end portion of the cylinder 76. The cylinder coupling portion
78 is formed in a substantially circular tube shape with an axial
direction in the vehicle width direction. The second coupling shaft
60 of the second arm 54 is inserted into the cylinder coupling
portion 78. An upper end portion of the cylinder 76 is thereby
coupled so as to be capable of swinging relative to the second arm
54.
[0060] When the gas generated by the gas generator 74 is supplied
into the cylinder 76, the cylinder 76 rises along the axial
direction of the actuator main body 72 by the pressure of the gas.
The rear end portion of the second arm 54 is thereby lifted toward
the upper side by the cylinder 76, thereby disposing the hood 10 at
a lifted position (the position illustrated by double-dotted
intermittent lines in FIG. 7). When this occurs, the second arm 54
swings about the second hinge pin 56 so as to swing toward the
upper side (toward the arrow C direction side in FIG. 3) relative
to the first arm 48. Linked to the swinging of the second arm 54,
the first arm 48 swings about the first hinge pin 50 so as to swing
toward the upper side (toward the arrow A direction side in FIG. 3)
relative to the hinge base 46.
[0061] The rear side actuator 70 includes a lock mechanism, not
illustrated in the drawings. When the cylinder 76 has lifted the
hood 10 to the lifted position due to actuation of the rear side
actuator 70, the cylinder 76 is restricted from retracting by the
lock mechanism.
[0062] Front PUH Device 80
[0063] As illustrated in FIG. 2 and FIG. 5, the front PUH device 80
is configured including the hood lock device 82 and a pair of left
and right front side actuators 110 that actuate in the event of a
collision with the pedestrian P.
[0064] Hood Lock Device 82
[0065] The hood lock device 82 is provided at a lower side of a
vehicle width direction intermediate portion of the front end
section of the hood 10. As illustrated in FIG. 5, the hood lock
device 82 is configured including a lock base 84, a hood lock body
90, and a fixing plate 96.
[0066] As illustrated in FIG. 6, the lock base 84 is formed
substantially in a rectangular plate shape with a plate thickness
direction in the front-rear direction. The lock base 84 is fastened
and fixed to an upper member of a radiator support, not illustrated
in the drawings. A vehicle width direction central portion of an
upper portion of the lock base 84 is formed with an escape recess
84A opening toward the upper side as viewed from the front, and the
anchor portion 16A of the hood striker 16 is disposed inside the
escape recess 84A. A first support pin 86 that swingably supports
the hood lock body 90, described later, is provided at a right side
portion of the upper portion of the lock base 84. The first support
pin 86 is formed in a substantially circular column shape, and
projects out from the lock base 84 toward the front side with an
axial direction in the front-rear direction. A guide hole 84B is
formed in a left side portion of the upper portion of the lock base
84. The guide hole 84B extends in the up-down direction, and curves
in a circular arc shape with its axial center at the center of the
first support pin 86.
[0067] The hood lock body 90 is disposed at the front side of the
lock base 84, and is formed in a substantially rectangular shape as
viewed from the front. A right side end portion of the hood lock
body 90 is swingably supported by the first support pin 86. The
hood lock body 90 is thereby capable of swinging in the up-down
direction (the arrow E and the arrow F directions in FIG. 6)
relative to the lock base 84 by swinging about the first support
pin 86.
[0068] A left side end portion of the hood lock body 90 is provided
with a guide pin 92. The guide pin 92 is formed in a circular
column shape, and projects out from the hood lock body 90 toward
the rear side with an axial direction in the front-rear direction.
The guide pin 92 is slidably inserted into the guide hole 84B of
the lock base 84.
[0069] An upper portion of the hood lock body 90 is formed with an
anchor recess 90A at a position at the front side of the escape
recess 84A of the lock base 84. The anchor recess 90A is formed in
a groove shape opening toward the upper side, and a width dimension
of the anchor recess 90A is set so as to become larger on
progression toward the upper side. In the closed position of the
hood 10, the anchor portion 16A of the hood striker 16 is disposed
at a lower end portion of the anchor recess 90A.
[0070] The hood lock body 90 is further provided with a latch 94.
The anchor portion 16A disposed in the lower end portion of the
anchor recess 90A is retained by the latch 94. A cable, not
illustrated in the drawings, is connected to the latch 94.
Operating the cable releases a retained state of the anchor portion
16A by the latch 94.
[0071] The fixing plate 96 is formed substantially in an open fan
shape as viewed from the front, and is disposed at a front side of
the hood lock body 90. A second support pin 98 with an axial
direction in the front-rear direction couples a base end portion of
the fixing plate 96 to the lock base 84 so as to be capable of
swinging.
[0072] A curved portion at an outer peripheral portion of the
fixing plate 96 configures a contact face 96A. The contact face 96A
is formed in a circular arc shape with an axial center at the
center of the second support pin 98. The contact face 96A abuts on
a circular column shaped fixing pin 100 provided at the hood lock
body 90, and in this state, prevents the hood lock body 90 from
swinging toward the upper side (the arrow E direction side in FIG.
6).
[0073] One end of a cable 102 is anchored to the fixing plate 96.
The other end of the cable 102 is anchored to a link mechanism 106
(see FIG. 5) that is engaged with the front side actuator 110,
described later. When the cable 102 is pulled toward the left side,
the fixing plate 96 is swung counterclockwise as viewed from the
front, and the state of contact of the contact face 96A of the
fixing plate 96 and the fixing pin 100 is released. The hood lock
body 90 accordingly assumes a state in which the hood lock body 90
is capable of swinging toward the upper side (the arrow E direction
side in FIG. 6), providing a configuration in which lifting of the
front end section of the hood 10 is possible.
[0074] The hood lock body 90 is formed with an escape portion, not
illustrated in the drawings, such that the fixing plate 96 and the
second support pin 98 do not impinge on the hood lock body 90 when
the hood lock body 90 swings. Moreover, the fixing plate 96 is
biased toward a clockwise direction as viewed from the front by a
spring 104.
[0075] Front Side Actuator 110
[0076] As illustrated in FIG. 5, the front side actuators 110 are
respectively provided on the right side and the left side of the
hood lock device 82. Each of the front side actuators 110 is formed
in a substantially circular column shape with an axial direction in
the up-down direction, and the lower end portion of each front side
actuator 110 is fixed to a radiator support (the vehicle body), not
illustrated in the drawings, through a plate shaped bracket 108.
The front side actuators 110 are disposed at a slight separation to
the lower side of both vehicle width direction end portions of the
front end section of the hood 10. Explanation follows regarding
configuration of the front side actuators 110.
[0077] FIG. 1A is a vertical cross-section illustrating a state of
the front side actuator 110 prior to actuation. FIG. 1B is a
vertical cross-section illustrating a state of the front side
actuators 110 after actuation. As illustrated in FIG. 1A and FIG.
1B, the front side actuator 110 is configured including a cylinder
112, an actuator main body 120, this being an example of a "main
body section" according to technology disclosed herein, and a
retention mechanism 130.
[0078] The cylinder 112 is formed substantially in a bottomed,
circular tube shape opening toward a lower side. An inner
peripheral face at an upper end side (one axial direction side) of
the cylinder 112 configures a general inner peripheral face 112A,
this being an example of a "general face" according to technology
disclosed herein. An inner peripheral face at an opening end side
(other axial direction side) of the cylinder 112 configures an
enlarged diameter portion 114 configuring the retention mechanism
130. As viewed in vertical cross-section, the enlarged diameter
portion 114 is formed with a stepped shape, so as to enlarge an
internal diameter of the cylinder 112, and is formed running around
the entire circumferential direction of the cylinder 112.
Specifically, the enlarged diameter portion 114 is configured
including an enlarged diameter inner peripheral face 114A, this
being an example of an "enlarged diameter face" according to
technology disclosed herein, that is disposed along the axial
direction of the cylinder 112 as viewed in vertical cross-section,
and an inclined face 114B configuring a boundary portion between
the enlarged diameter inner peripheral face 114A and the general
inner peripheral face 112A. The internal diameter of the enlarged
diameter inner peripheral face 114A is set larger than an internal
diameter of the general inner peripheral face 112A, and is set
larger than an external diameter of an 0-ring 126, described later.
The inclined face 114B is inclined toward the one axial direction
side of the cylinder 112 on progression toward a radial direction
inner side of the cylinder 112 as viewed in vertical
cross-section.
[0079] A head portion 116 is provided at an opening end portion
(lower end portion) of the cylinder 112. The head portion 116 is
formed in a substantially circular tube shape, and is fitted
(fixed) inside the enlarged diameter portion 114. An inner
peripheral portion of the head portion 116 is formed with plural
communication grooves 116A that penetrate the head portion 116 in
the up-down direction and that are open at a radial direction inner
side of the head portion 116. The communication grooves 116A impose
a space G between the actuator main body 120, which is described
below, and the cylinder 112, the space G being in communication
with the exterior of the cylinder 112. Note that the plural
communication grooves 116A are disposed at a specific spacing
around the circumferential direction of the head portion 116.
[0080] The actuator main body 120 is formed in a substantially
circular tube shape, and is disposed coaxially to the cylinder 112.
An external diameter dimension of the actuator main body 120 is set
smaller than an internal diameter dimension of the general inner
peripheral face 112A of the cylinder 112. With the exception of a
lower end portion, the actuator main body 120 is housed inside the
cylinder 112 so as to be capable of moving relative to the cylinder
112. The lower end portion of the actuator main body 120 is fixed
to the radiator support by the bracket 108, described above. In
other words, the cylinder 112 covers a portion on one axial
direction side of the actuator main body 120 so as to enable
relative movement in the up-down direction. The space G is
configured by a space between an inner peripheral portion of the
cylinder 112 and an outer peripheral portion of the actuator main
body 120.
[0081] The substantially circular column shaped gas generator 122
is fitted into an up-down direction intermediate portion of the
actuator main body 120. The gas generator 122 is configured
similarly to the gas generator 74 of the rear side actuator 70
described above. Namely, the gas generator 122 includes a squib
(ignition device), and the inside of the gas generator 122 is
filled with a gas generating agent. Wire harnesses 122A are
connected to a lower end of the gas generator 122, and the gas
generator 122 is electrically connected to the ECU 140 (see FIG.
2), described later, through the wire harnesses 122A. The gas
generator 122 is accordingly actuated under the control of the ECU
140. When the gas generator 122 is actuated, gas generated by the
gas generator 122 is supplied into the actuator main body 120. Note
that the wire harnesses 122A extending out from a lower end of the
gas generator 122 are laid out inside the actuator main body 120,
and lead out from the lower end portion of the actuator main body
120 toward the outer side. The inside of the actuator main body 120
is filled with a resin material, thereby integrating the wire
harnesses 122A and the actuator main body 120 together.
[0082] A first enlarged diameter portion 124 is formed projecting
out toward the radial direction outer side at an upper end portion
of the actuator main body 120. An external diameter dimension of
the first enlarged diameter portion 124 is set slightly smaller
than the internal diameter dimension of the general inner
peripheral face 112A of the cylinder 112. An outer peripheral
portion of the first enlarged diameter portion 124 is formed with a
sealing groove portion 124A. The sealing groove portion 124A opens
toward the radial direction outer side of the actuator main body
120, and is formed running around the entire peripheral direction
of the first enlarged diameter portion 124. The O-ring 126, this
being an example of a "sealing member" according to technology
disclosed herein, configured by a rubber material or the like, is
provided inside the sealing groove portion 124A. The O-ring 126
forms a seal between the actuator main body 120 and the cylinder
112 (the general inner peripheral face 112A). Namely, the O-ring
126 blocks off the inside of the cylinder 112 from the space G
[0083] A second enlarged diameter portion 128 is formed at an outer
peripheral portion of the actuator main body 120, at a position
further toward a lower end side of the actuator main body 120 than
the first enlarged diameter portion 124. An external diameter
dimension of the second enlarged diameter portion 128 is set
substantially the same as the external diameter dimension of the
first enlarged diameter portion 124. A housing groove 128A
configuring the retention mechanism 130 is formed at an outer
peripheral portion of the second enlarged diameter portion 128. The
housing groove 128A opens toward the radial direction outer side of
the actuator main body 120, and is formed running around the entire
peripheral direction of the actuator main body 120. Specifically,
as viewed in vertical cross-section, the housing groove 128A is
configured including a bottom face 128A1 disposed running in the
axial direction (up-down direction) of the actuator main body 120,
an upper face 128A2 extending from an upper end of the bottom face
128A1 toward the radial direction outer side of the actuator main
body 120, and a lower inclined face 128A3 inclined from a lower end
of the bottom face 128A1 toward the lower end side of the actuator
main body 120 on progression toward the radial direction outer side
of the actuator main body 120.
[0084] A C-ring 132, configuring the retention mechanism 130 and
being an example of a "retention member" according to technology
disclosed herein is disposed (housed) inside the housing groove
128A. The C-ring 132 is configured from a metal wire member with a
circular cross-section profile, and is formed in a partially open
annular shape (a ring shape, specifically, a substantially
C-shape). The C-ring 132 has spring properties, and is configured
so as to be capable of elastic deformation in its radial direction.
The C-ring 132 is housed inner side the housing groove 128A in a
state elastically deformed toward the radial direction inner side
(having a reduced diameter) from a natural state (a state in which
the C-ring 132 is not elastically deformed), and contacting the
general inner peripheral face 112A of the cylinder 112 (see FIG.
1A).
[0085] When the gas generator 122 actuates, gas generated by the
gas generator 122 is supplied into the actuator main body 120, and
the cylinder 112 moves toward the upper side (rises) relative to
the actuator main body 120 by the pressure of the gas inside the
actuator main body 120. Configuration is thereby made such that an
upper end portion of the cylinder 112 accordingly contacts the hood
10, and the front end section of the hood 10 is lifted to the
lifted position (the position illustrated by double-dotted
intermittent lines in FIG. 5 and FIG. 7). When the cylinder 112
moves toward the upper side relative to the actuator main body 120,
the inner peripheral face (the general inner peripheral face 112A
and the enlarged diameter inner peripheral face 114A) of the
cylinder 112 is configured to slide against an outer peripheral
portion of the C-ring 132, such that frictional force is generated
between the C-ring 132 and the cylinder 112. As illustrated in FIG.
1B, at the lifted position, an upper end of the head portion 116 of
the cylinder 112 abuts on a lower end of the second enlarged
diameter portion 128, and an upper end of the enlarged diameter
portion 114 of the cylinder 112 is configured so as to be disposed
at the radial direction outer side of the actuator main body 120
with respect to the O-ring 126. Moreover, as described above, the
internal diameter of the enlarged diameter portion 114 (the
enlarged diameter inner peripheral face 114A) is set larger than
the external diameter of the O-ring 126. Accordingly, configuration
is made such that at the lifted position, a gap is formed between
the O-ring 126 and the enlarged diameter portion 114, and the
inside of the cylinder 112 and the space G are placed in
communication with each other through the enlarged diameter portion
114. Configuration is thereby made such that the gas supplied into
the cylinder 112 (actuator main body 120) is discharged (escapes)
to the exterior of the cylinder 112 through the enlarged diameter
portion 114. Note that the space G is partitioned into an upper
portion and a lower portion by the C-ring 132. However, since the
C-ring 132 is formed in a partially open annular shape, the upper
portion and the lower portion of the space G are in communication
with each other through the portion where the C-ring 132 is
partially open. In order to improve the flow of gas from the upper
portion to the lower portion of the space a communication groove
(not illustrated in the drawings) may be formed penetrating the
second enlarged diameter portion 128 in the up-down direction and
opening toward the radial direction outer side of the actuator main
body 120.
[0086] As illustrated in FIG. 5, the link mechanism 106 is engaged
with the cylinder 112 of the front side actuator 110 disposed on
the left side of the hood lock device 82, and the other end of the
cable 102 described above is anchored to the link mechanism 106.
When the cylinder 112 rises during actuation of the front side
actuator 110, the link mechanism 106 is actuated and the cable 102
is pulled toward the left side. Accordingly, configuration is made
such that during actuation of the front side actuator 110, the
state of contact of the contact face 96A of the fixing plate 96
with the fixing pin 100 is released, enabling lifting of the front
end section of the hood 10.
[0087] In the present exemplary embodiment, the lifting force
(actuation force) of the front side actuators 110 is set such that
the hood 10 can be lifted together with a pedestrian P falling onto
the hood 10. Moreover, when the gas inside the cylinder 112 escapes
following actuation of the front side actuator 110 and a specific
collision load toward the lower side is input to the cylinder 112
through the hood 10, the cylinder 112 moves toward the lower side
relative to the actuator main body 120, against the frictional
force between the C-ring 132 and the cylinder 112. As illustrated
in FIG. 9B, when the cylinder 112 moves toward the lower side
relative to the actuator main body 120, the C-ring 132 is gripped
in the up-down direction between the inclined face 114B of the
enlarged diameter portion 114 and the lower inclined face 128A3 of
the housing groove 128A, such that the cylinder 112 engages with
the C-ring 132. The cylinder 112 is thereby restricted from
retracting, and the hood 10 is retained at the lifted position by
the retention mechanism 130. This position is referred to below as
the retention position.
[0088] Explanation follows regarding the specific collision load.
The collision load is set based on pedestrian head protection
performance testing as stipulated by the Japan New Car Assessment
Program (JNCAP). Namely, the collision load is defined as the load
acting on (input to) the cylinder 112 when a head impactor, this
being a collision body simulating the head of an adult or child,
collides with the hood 10 from a testing machine. In a collision
between the vehicle and a pedestrian, a pedestrian with a
comparatively small physical build, such as a child, will tend to
fall predominantly onto the front end section of the hood 10.
Accordingly, in the present exemplary embodiment, the load that
acts on (is input to) the cylinder 112 when a head impactor
modelled on a child with a small physical build collides with the
front end section of the hood 10 is set as the collision load.
[0089] ECU 140
[0090] As illustrated in FIG. 2, a collision detection sensor 142
and a collision prediction sensor 144 are electrically connected to
the ECU 140. The ECU 140 determines whether or not to actuate the
rear side actuators 70 and the front side actuators 110 based on
signals output from the collision detection sensor 142 and the
collision prediction sensor 144. First, explanation is given
regarding the collision detection sensor 142 and the collision
prediction sensor 144, followed by explanation regarding the ECU
140.
[0091] The collision detection sensor 142 is installed at a front
face of bumper reinforcement (not illustrated in the drawings) of a
front bumper 22 disposed at a front end section of the vehicle V.
The collision detection sensor 142 is configured including a
substantially elongated pressure tube 142A with a length direction
in the vehicle width direction, and pressure sensors 142B provided
at both length direction ends of the pressure tube 142A.
Configuration is made such that when a collision body such as the
pedestrian P collides with the front bumper 22, the pressure inside
the pressure tube 142A changes, and signals corresponding to the
pressure change inside the pressure tube 142A are output from the
pressure sensors 142B to the ECU 140. Note that the collision
detection sensor 142 may also have a configuration employing
pressure chambers or optical fibers.
[0092] The collision prediction sensor 144 is configured by a
stereo camera. The stereo camera is provided in the vicinity of the
vehicle width direction center of an upper portion of the
windshield glass WG The stereo camera photographs the front side of
the vehicle V, and detects a collision body that could collide with
the vehicle V. The stereo camera measures the distance to the
detected collision body, the relative speed between the vehicle V
and the collision body, and the like, and outputs the measurement
data to the to the ECU 140. Note that the collision prediction
sensor 144 may also be configured by a millimeter wave radar or the
like.
[0093] The ECU 140 then computes a collision load based on the
output signals of the pressure sensors 142B described above, and
also computes a collision speed based on the output signals of the
collision prediction sensor 144. Moreover, the ECU 140 finds an
effective mass for the collision body from the computed collision
load and collision speed, determines whether or not the effective
mass exceeds a threshold value, and determines whether the
collision body that could collide with the vehicle V is the
pedestrian P or something other than the pedestrian P (for example,
a roadside obstacle such as a roadside marker or a guide post).
Configuration is made such that the PUH device 30 is actuated by
the ECU 140 when the ECU 140 has determined that the collision body
that could collide with the vehicle V is the pedestrian P.
[0094] The front side actuators 110 are set so as to actuate before
the rear side actuators 70 during actuation of the PUH device 30.
Specifically, configuration is made such that when the pedestrian P
has collided with the front bumper 22, the front side actuator 110
is actuated by the ECU 140 either at the same time as the body of
the pedestrian P falls onto the hood 10 and contacts the front end
section of the hood 10, or after the body of the pedestrian P has
contacted the front end section of the hood 10. In other words, an
actuation timing of the front side actuator 110 is set to after a
first specific duration has elapsed from the time of the collision
between the pedestrian P and the front bumper 22.
[0095] In the present exemplary embodiment, the first specific
duration is set by measuring the time taken for a dummy falling
onto the hood 10 to contact the front end section of the hood 10 by
carrying out crash tests using a dummy. Specifically, the first
specific duration (15 msec in the present exemplary embodiment) is
set by measuring the time taken for a dummy to contact the front
end section of the hood 10 when the vehicle V travelling at a speed
of 40 km/h collides with a dummy modeled on a child (6 year old
child). Note that crash testing has revealed that the time taken
for the dummy falling onto the hood 10 to contact the front end
section of the hood 10 is substantially the same when employing a
dummy modeled on an adult (for example, a dummy covering 50% of
American adult males (AM50)) as when employing a dummy modeled on a
child (6 year old child). Accordingly, the first specific duration
is set so as to be able to correspond to anyone from a child to an
adult.
[0096] The ECU 140 is set to actuate the rear side actuators 70
after a second specific duration has elapsed following the start of
actuation of the front side actuators 110. Specifically, the second
specific duration (the actuation timing of the rear side actuators
70) is set such that the head of the pedestrian P strikes the hood
10 after actuation of the rear side actuators 70 has completed.
Note that the second specific duration is also set by carrying out
crash testing using various dummy types. Moreover, the first
specific duration and the second specific duration are set
corresponding to the vehicle type.
[0097] Next, explanation follows regarding operation and
advantageous effects of the present exemplary embodiment.
[0098] In the non-actuated state of the PUH device 30, the hood 10
is disposed at the closed position, and the engine room ER is
closed off by the hood 10 (see the hood 10 illustrated by solid
lines in FIG. 7). From this state, in the event of a frontal
collision between a collision body such as the pedestrian P and the
vehicle V, the collision detection sensor 142 detects that there
has been a frontal collision with the collision body, and a signal
is output from the collision detection sensor 142 to the ECU 140.
When this is performed, using the collision detection sensor 142
and the collision prediction sensor 144, the ECU 140 determines
whether the collision body that has collided with the vehicle V is
the pedestrian P or something other than the pedestrian P. The PUH
device 30 is actuated by the ECU 140 when the ECU 140 determines
the collision body that has collided with the vehicle V to be the
pedestrian P.
[0099] During actuation of the PUH device 30, first, the gas
generator 122 of each front side actuator 110 is actuated under the
control of the ECU 140. Specifically, the gas generator 122 is
actuated 15 msec after the start of the collision between the
pedestrian P and the vehicle V, and gas is supplied into the
actuator main body 120. When gas is supplied into the actuator main
body 120, the cylinder 112 is pushed by the pressure of the gas
inside the actuator main body 120, and the cylinder 112 moves
(rises) toward the upper side relative to the actuator main body
120. When this occurs, the cable 102 of the front PUH device 80 is
pulled toward the left side, linked to the movement of the cylinder
112. The fixing plate 96 accordingly swings, enabling the hood lock
body 90 to swing toward the upper side. Namely, lifting of the
front end section of the hood 10 is enabled. When the cylinder 112
moves toward the upper side, the upper end portion of the cylinder
112 contacts the hood 10 and lifts the front end section of the
hood 10 toward the upper side. The front end section of the hood 10
is thereby lifted to the lifted position (see the double-dotted
intermittent lines in FIG. 5).
[0100] After the second specific duration has elapsed following the
start of actuation of the front side actuators 110, the gas
generator 74 of each rear side actuator 70 is actuated under the
control of the ECU 140, thereby supplying gas inside the actuator
main body 72. The cylinder 76 thereby moves (rises) in the axial
direction toward the upper side with respect to the actuator main
body 72 by the pressure of the gas inside the actuator main body
72. When the cylinder 76 rises, the cylinder 76 lifts the rear end
portion of the second arm 54 toward the upper side, lifting the
rear end section of the hood 10 to the lifted position. In this
manner, the front end section and the rear end section of the hood
10 are lifted to the lifted position, and a spacing between the
inside of the engine room ER and the hood 10 is secured.
[0101] Next, explanation follows regarding the actuation state of
the front side actuator 110 and the state of the pedestrian P in
chronological order when the pedestrian P collides with the front
bumper 22. The state illustrated in FIG. 8A is a state prior to
actuation of the front side actuator 110. When the pedestrian P
collides with the front bumper 22, predominantly the legs of the
pedestrian P strike the front bumper 22, such that the pedestrian P
falls onto the hood 10 from the front end side of the hood 10. The
front side actuator 110 is actuated by the ECU 140 either at the
same time as the body of the pedestrian P falling onto the hood 10
contacts the front end section of the hood 10, or after the body of
the pedestrian P has contacted the front end section of the hood
10.
[0102] As illustrated in FIG. 8B, when the front side actuator 110
actuates, the cylinder 112 instantaneously moves (rises) toward the
upper side relative to the actuator main body 120 by the gas
generated by the gas generator 122. The front side actuator 110
accordingly lifts the front end section of the hood 10 together
with the lumbar and upper body of the pedestrian P falling onto the
hood 10. Namely, the pedestrian P falls onto the hood 10 while the
lumbar and upper body of the pedestrian P are lifted. A load f (see
FIG. 10) toward the upper side accordingly acts on the body of the
pedestrian P falling onto the hood 10, thereby enabling a head
velocity v (see FIG. 10) of the pedestrian P falling onto the hood
10 toward the lower side to be reduced. Note that when the cylinder
112 rises with respect to the actuator main body 120, the enlarged
diameter portion 114 of the cylinder 112 is disposed at the radial
direction outer side of the actuator main body 120 with respect to
the C-ring 132, and the C-ring 132 elastically deforms toward the
radial direction outer side and contacts the enlarged diameter
inner peripheral face 114A of the enlarged diameter portion
114.
[0103] Note that as illustrated in FIG. 9A, when the cylinder 112
(hood 10) has risen further from the state illustrated in FIG. 8B
and has been lifted to the lifted position, an upper end portion of
the enlarged diameter portion 114 of the cylinder 112 is disposed
at the radial direction outer side of the actuator main body 120
with respect to the O-ring 126 of the actuator main body 120. The
internal diameter dimension of the enlarged diameter portion 114
(enlarged diameter inner peripheral face 114A) is set larger than
the external diameter dimension of the O-ring 126. Accordingly, the
inside of the cylinder 112 and the space G between the cylinder 112
and the actuator main body 120 are placed in communication with
each other through the enlarged diameter portion 114. The gas
inside the cylinder 112 is thereby discharged to the exterior of
the cylinder 112 through the enlarged diameter portion 114, the
space and the communication grooves 116A of the head portion 116
(see the arrows H in FIG. 9A). Namely, gas inside the cylinder 112
can be discharged to the exterior without forming gas escape holes
in the cylinder 112. Accordingly, the effect of the assembly
precision of the front side actuator 110 on actuation of the front
side actuator 110 can be suppressed.
[0104] Namely, supposing gas escape holes were to be formed in the
cylinder 112, it is possible that due to assembly variation in the
front side actuator 110, the peripheries of openings of the gas
escape holes could catch on the C-ring 132 when the cylinder 112
moves. There would accordingly be a need for high assembly
precision of the front side actuator 110 in order to prevent the
peripheries of the openings of gas escape holes from catching on
the C-ring 132. In other words, in such cases, there is a
possibility that actuation of the front side actuator 110 could be
affected by the assembly precision of the front side actuator 110.
In contrast, as described above, the present exemplary embodiment
enables the gas inside the cylinder 112 to be discharged to the
exterior without forming gas escape holes in the cylinder 112.
Actuation of the front side actuator 110 is therefore not affected
by the peripheries of the openings of gas escape holes, enabling
movement of the cylinder 112. This thereby enables the effect of
the assembly precision of the front side actuator 110 on actuation
to be suppressed in comparison to configurations in which gas
escape holes are formed in the cylinder 112.
[0105] In this state, the gas inside the cylinder 112 is discharged
to the exterior, thereby achieving a state in which high pressure
gas is suppressed from remaining in the cylinder 112. Accordingly,
in this state, a reaction force from the hood 10 on the head of the
pedestrian P when the head of the pedestrian P falling onto the
hood 10 strikes the hood 10 can be reduced. The cylinder 112 moves
toward the lower side relative to the actuator main body 120
against the frictional force between the C-ring 132 and the
cylinder 112 when a specific collision load toward the lower side
acts on the cylinder 112 due to the head of the pedestrian P
striking the hood 10. Namely, the cylinder 112 moves toward the
lower side relative to the actuator main body 120 while the
enlarged diameter inner peripheral face 114A of the enlarged
diameter portion 114 slides against the outer peripheral portion of
the C-ring 132. This thereby enables collision energy to the head
of the pedestrian P to be absorbed by the frictional force. In
particular, collision energy to the head of a pedestrian P with a
small build can be absorbed since there is a tendency for the head
of the pedestrian P falling onto the hood 10 to strike
predominantly the front end section of the hood 10 in a collision
between a pedestrian P with a small build and the vehicle V. This
thereby enables the injury criteria of the pedestrian P to be
lowered, while suppressing the effect of assembly precision of the
front side actuator 110 on actuation of the front side actuator
110.
[0106] As illustrated in FIG. 9B, when the cylinder 112 reaches the
retention position as a result of the cylinder 112 moving toward
the lower side relative to the actuator main body 120, the inclined
face 114B of the enlarged diameter portion 114 engages with the
C-ring 132, restricting movement of the cylinder 112 toward the
lower side. The cylinder 112 (hood 10) is thereby retained at the
retention position. This thereby enables the cylinder 112 (hood 10)
to be retained at the retention position by utilizing the inclined
face 114B of the enlarged diameter portion 114.
[0107] Due the configuration by which the C-ring 132 engages with
the inclined face 114B of the enlarged diameter portion 114 to
retain the cylinder 112 (hood 10) at the retention position, the
axial direction length of the cylinder 112 can be made shorter than
in cases in which, for example, gas escape holes are formed in the
cylinder 112. Explanation follows regarding this point, with
reference to FIG. 11. FIG. 11 comparatively illustrates relevant
portions of a front side actuator of a comparative example, and
relevant portions of the front side actuator 110 of the present
exemplary embodiment. The front side actuator of the comparative
example is illustrated in vertical cross-section on the left side
of the single-dotted intermittent lines in FIG. 11, and the front
side actuator 110 of the present exemplary embodiment is
illustrated in vertical cross-section on the right side of the
single-dotted intermittent lines in FIG. 11. In the front side
actuator of the comparative example illustrated in FIG. 11, members
configured similarly to those of the present exemplary embodiment
are allocated the same reference numerals. Moreover, FIG. 11
illustrates a state immediately prior to gas escaping from inside
the cylinder 112.
[0108] As illustrated in FIG. 11, in the front side actuator of the
comparative example, a gas escape hole 150 is formed in the
cylinder 112. The position of the gas escape hole 150 is set at the
upper side of the inclined face 114B that engages with the C-ring
132 at the retention position. In other words, the inclined face
114B is disposed further to the lower side than the gas escape hole
150. Accordingly, the inclined face 114B and the C-ring 132 are
disposed further to the lower side than in the present exemplary
embodiment. Namely, in the present exemplary embodiment, the
inclined face 114B configuring the upper end portion of the
enlarged diameter portion 114 through which gas escapes from inside
the cylinder 112 functions as a face that engages with the C-ring
132, and so the inclined face 114B and the C-ring 132 can be
disposed further toward the upper side than in the comparative
example by an amount commensurate with a diameter dimension of the
gas escape hole 150. Accordingly, the axial direction length of the
cylinder 112 of the present exemplary embodiment can be made
shorter than the axial direction length of the cylinder 112 of the
comparative example (see arrow L in FIG. 11). The present exemplary
embodiment thereby enables a contribution to be made to reducing
the size of the front side actuator 110, and also enables a
reduction in weight of the front side actuator 110.
[0109] The inclined face 114B of the enlarged diameter portion 114
is inclined toward the one axial direction side of the cylinder 112
on progression toward the radial direction inner side of the
cylinder 112. Accordingly, the O-ring 126 and the C-ring 132 can be
suppressed from catching on the inclined face 114B when the
actuator main body 120 is inserted into the cylinder 112 compared
to cases in which, for example, the inclined face 114B side
disposed running in a direction orthogonal to the axis of the
cylinder 112. Damage to the O-ring 126 and the C-ring 132 is
accordingly further suppressed, enabling the reliability of the
front side actuator 110 to be improved.
[0110] In the present exemplary embodiment, the C-ring 132 is
formed with a partially open C-shaped ring profile, and has spring
properties. In a reduced-diameter state of the C-ring 132, the
C-ring 132 abuts on the general inner peripheral face 112A of the
cylinder 112, and is housed inside the housing groove 128A of the
actuator main body 120. This thereby enables the C-ring 132 that
retains the cylinder 112 at the retention position to be suppressed
from being exposed to the exterior of the cylinder 112.
[0111] The PUH device 30 includes the rear side actuators 70 in
addition to the front side actuators 110. The rear end section of
the hood 10 is thereby lifted by the rear side actuators 70. This
thereby enables the head of a pedestrian P of comparatively large
build falling onto the hood 10 to strike the hood 10 earlier than,
for example, in cases in which the rear end section of the hood 10
is not lifted. The collision energy to the head of the pedestrian P
can be reduced as a result.
[0112] In the present exemplary embodiment, the rear side actuators
70 are actuated by the ECU 140 after actuation of the front side
actuators 110. This thereby enables the front end section of the
hood 10 to be lifted by the front side actuators 110 at an early
stage.
[0113] Explanation follows regarding this point. When the rear side
actuators 70 actuate, the rear end section of the hood 10 is
lifted, such that a rotation moment acts on the hood 10 about the
center of gravity of the hood 10 as viewed from the side,
displacing the front end section of the hood 10 toward the lower
side. Accordingly, if the rear side actuators 70 and the front side
actuators 110 were to be actuated at the same time as each other,
the rotation moment acting on the hood 10 would affect lifting of
the hood 10 by the front side actuators 110. As a result, there
would be a possibility of lifting of the front end section of the
hood 10 being delayed.
[0114] In contrast, in the present exemplary embodiment, the rear
side actuators 70 are actuated by the ECU 140 after actuation of
the front side actuators 110. Accordingly, since the rear side
actuators 70 are not actuated at the start of actuation of the
front side actuators 110, the rotation moment described above does
not act on the hood 10 during initial actuation of the hood 10 by
the front side actuators 110. The front end section of the hood 10
can accordingly be lifted by the front side actuators 110 without
being affected by rotation moment arising in the hood 10 until the
rear side actuators 70 are actuated. This thereby enables the front
end section of the hood 10 to be lifted at an early stage.
[0115] Note that in the present exemplary embodiment, configuration
is made such that retraction of the cylinder 76 with respect to the
actuator main body 72 is restricted by the lock mechanism, not
illustrated in the drawings, of the rear side actuator 70.
Alternatively, the enlarged diameter portion 114 and the retention
mechanism 130 may also be provided at the rear side actuators 70,
similarly to in the front side actuators 110. Namely, configuration
may be made such that gas inside the cylinder 76 escapes following
actuation of the rear side actuators 70, and the rear end section
of the hood 10 is displaced toward the lower side when a specific
collision load acts on the rear end section of the hood 10.
[0116] In the present exemplary embodiment, configuration is made
such that the front side actuators 110 are actuated by the ECU 140
either at the same time as the body of the pedestrian P falling
onto the hood 10 contacts the front end section of the hood 10, or
after the body of the pedestrian P contacts the front end section
of the hood 10. However, the actuation timing of the front side
actuators 110 may be set as desired according to the vehicle
type.
[0117] In the present exemplary embodiment, configuration is made
such that the vehicle width direction central portion of the front
end section of the hood 10 is locked by the hood lock device 82 of
the front PUH device 80. Alternatively, configuration may be made
in which both vehicle width direction end portions of the front end
section of the hood 10 are locked by the front PUH device 80.
[0118] In the present exemplary embodiment, configuration is made
in which both vehicle width direction end portions of the front end
section of the hood 10 are lifted by the pair of left and right
front side actuators 110 of the front PUH device 80. Alternatively,
configuration may be made in which one out of the pair of front
side actuators 110 is omitted, and a vehicle width direction
central portion of the front end section of the hood 10 is lifted
by the remaining front side actuator 110.
[0119] All cited documents, patent applications, and technical
standards mentioned in the present specification are incorporated
by reference in the present specification to the same extent as if
the individual cited document, patent application, or technical
standard was specifically and individually indicated to be
incorporated by reference.
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