JP5136527B2 - Actuator - Google Patents

Description

  The present invention relates to an actuator used in an automobile safety device, and more particularly, to an actuator used for an operation such as lifting a hood panel when receiving a pedestrian as an object to be protected.

  Conventionally, as an actuator used in an automobile safety device, a piston disposed in a cylinder by a working gas generated from a gas generator provided in a cylindrical cylinder, together with a support rod connected to the piston There was a piston cylinder type to be moved (for example, see Patent Document 1).

JP 2002-173391 A

  In this conventional actuator, the piston is moved by using the pressing force of the working gas. When used in a safety device for automobiles, the support rod must be moved instantaneously. It is desired to move quickly. In particular, when this type of actuator is disposed below the rear end side of the hood panel of the vehicle and the rear end side of the hood panel is raised during operation, the hood panel made of sheet metal is pushed upward by the support rod. Therefore, it is necessary to efficiently press the piston by the pressing force of the working gas. However, in the conventional actuator, the distance between the gas generator and the bottom surface of the piston is large, and the working gas generated from the gas generator flows out radially between the gas generator and the bottom surface of the piston. Since there are those that go to the inner peripheral surface of the cylinder, there is room for improvement in that it is difficult to immediately apply the pressing force of the working gas to the bottom surface of the piston, and the piston is moved quickly.

  The present invention solves the above-described problems, and an object thereof is to provide an actuator capable of rapidly moving a piston forward during operation.

The actuator according to the present invention is used in an automobile safety device,
A piston cylinder type actuator that moves a piston arranged in a cylinder together with a support rod connected to the piston by a working gas generated from a gas generator provided in a cylindrical cylinder,
The gas generator is configured to include a housing filled with a gas generating agent that generates a working gas during combustion, and a squib that can ignite the gas generating agent.
In the housing, when the squib is activated, the ceiling wall arranged opposite to the bottom surface of the piston before the operation breaks the planned fracture portion arranged around it, and the part located near the center is opened. It is configured to have a plurality of doors that open as the tip side,
The bottom surface of the piston has a concave part that makes the surface concave in the vicinity of the center, and when the door part opens, the front part of the door part can be brought into contact with the concave part when it opens. Alternatively, the peripheral wall portion constituting the peripheral edge of the concave portion in the bottom surface portion is configured to be able to be overlapped on the outer side in the radial direction from the central axis of the piston with respect to the front end of each door portion. .

  In the actuator according to the present invention, when the squib of the gas generator is ignited at the time of operation, the planned break portion formed on the ceiling wall of the housing filled with the gas generating agent is broken, and the door portions are respectively The part located near the center is opened as the tip when opening, and the working gas generated by the combustion of the gas generating agent flows out into the cylinder, and the piston stored in the cylinder operates. It is pushed by the working gas and moves forward together with the support rod. In the actuator of the present invention, in the housing of the gas generator, the ceiling wall on which the planned fracture portion is disposed is disposed to face the bottom surface of the piston before operation, and the bottom surface of the piston is in the center. There is a concave part that dents the surface in the vicinity, and when the door part is opened, the front part of the door part can be brought into contact with the concave part so that the front part of the door part can come into contact. The peripheral wall part which comprises the recessed part periphery in a bottom face part with respect to the front-end | tip is comprised so that it can overlap on the outward side of a radial direction from the central axis of a piston. Therefore, if the door part is opened during operation, the door part opens with the tip entering the recess, so that the space between the gas generator and the bottom part of the piston is the open door part and the bottom part of the piston. The working gas generated by the combustion of the gas generating agent is covered in the direction perpendicular to the axis, in other words, the axial orthogonal direction side is covered over the substantially entire surface (substantially the entire circumference) by the recess provided in If it does so, it will flow so that it may flow toward the bottom face part side of a piston, suppressing flowing so that it may go to the inner peripheral surface side of a cylinder. At this time, if the front end of the open door portion is in contact with the bottom surface portion of the piston in the recess, the region surrounded by the open door portion and the bottom surface portion of the piston is filled with the working gas, Since the internal pressure in this region can be quickly increased, the pressing force of the working gas can be instantaneously applied to the bottom surface portion along the direction of movement of the piston. Further, if the bottom surface portion of the piston is configured to overlap the peripheral wall portion constituting the peripheral edge of the recess in the bottom surface portion on the outer side in the radial direction from the central axis of the piston with respect to the tip of each door portion, Even if a gap is formed between the opened door and the bottom surface of the piston, and the working gas flows outward in the radial direction from this clearance, the recess in the bottom surface of the piston Since the peripheral wall portion of the peripheral edge covers the outer side of the tip of the open door portion, the working gas is formed in the peripheral wall portion of the peripheral edge of the concave portion of the bottom surface portion of the piston in the region overlapping the open door portion. Thus, the pressing force of the filled working gas can be instantaneously applied to the bottom surface along the moving direction of the piston. As a result, the pressing force of the working gas can be instantaneously applied to the bottom surface of the piston, and the piston can be rapidly moved forward.

  Therefore, in the actuator of the present invention, the piston can be rapidly moved forward during operation.

  In particular, in the actuator of the present invention, when the door portion is opened, the distal end enters the recess, so that the opened door portion constitutes a guide tube having the distal end entered the recess. In this mode, the generated working gas can be surely flown out into the recess, and the pressing force of the working gas can be applied to the bottom surface of the piston without waste.

  Further, in the actuator of the present invention, if each door portion formed on the ceiling wall is configured to open radially with substantially the same outer shape when opened, the gas generator and the bottom surface of the piston are opened by the opened door portion. The axial orthogonal direction side of the space between the portions can be covered substantially uniformly over substantially the entire surface (entire circumference). Therefore, the pressing force of the working gas can be applied to the substantially circular area with the center of the bottom surface as a reference with respect to the bottom surface of the piston, and the piston moves forward more linearly at the beginning of the operation. This is preferable.

  Furthermore, in the actuator according to the present invention, when each door portion formed on the ceiling wall is configured such that the portion on the base portion side that becomes the rotation center at the time of opening is positioned outward from the outer peripheral edge of the concave portion, In the state where each of the door portions has an opening angle of less than 90 °, the tip is brought into contact with the inner peripheral surface (side surface on the axis orthogonal direction side) of the recess. Therefore, in the actuator configured as described above, each door portion is prevented from opening at a large opening angle, and a gap generated between the door portions when opening can be minimized, so that the operating gas is generated between the door portions. It is preferable that the piston can be prevented from leaking as much as possible, and the piston can be efficiently moved forward at the beginning of operation.

  Furthermore, in the actuator configured as described above, if an O-ring made of a rubber-like elastic body is provided on the outer peripheral surface of the piston so as to be in sliding contact with the inner peripheral surface of the cylinder, an airtightness between the piston and the cylinder is provided. Therefore, it is preferable that the operating gas can be prevented from leaking between the piston and the cylinder before the piston is moved during operation, and the piston can be moved forward quickly. Furthermore, although this O-ring is arranged on the outer peripheral surface side of the piston and is arranged in the vicinity of the gas generator in a state before operation, in the actuator configured as described above, in the initial operation of the gas generator, Since the generated working gas can be prevented from moving toward the inner peripheral surface of the cylinder on the side perpendicular to the axis, it is possible to suppress the hot working gas from hitting the O-ring as much as possible in the initial stage of operation. It is possible to suppress the deterioration of the O-ring that reduces the airtightness between the piston and the cylinder.

1 is a perspective view of a vehicle on which a hood flip-up device using an actuator according to an embodiment of the present invention is mounted. It is a partial enlarged plan view of the vehicle carrying the hood flip-up device using the actuator of the embodiment. It is a schematic longitudinal cross-sectional view along the front-back direction which shows the hood flip-up apparatus and vehicle hinge part of embodiment, and respond | corresponds to the III-III site | part of FIG. It is a schematic sectional drawing which shows the time of the action | operation of the hood flip-up apparatus using the actuator of embodiment. It is a schematic longitudinal cross-sectional view of the actuator of embodiment, and shows the time before an operation | movement and the time of an operation completion. It is a partial expanded schematic longitudinal cross-sectional view which shows the site | part of the front-end | tip wall part of the cylinder in the actuator of embodiment. In the actuator of embodiment, it is a general | schematic partial enlarged longitudinal cross-sectional view explaining the action | operation of a locking mechanism in order. It is a partial expanded schematic longitudinal cross-sectional view which shows the gas generator and piston in the actuator of embodiment. It is a partial expanded sectional view which shows the ceiling wall vicinity of the housing used for the gas generator of the actuator of embodiment. It is a schematic perspective view which shows the ceiling wall vicinity of the housing used for the gas generator of the actuator of embodiment. In the actuator of an embodiment, it is a partial expanded sectional view showing the state where the squib of the gas generator operated. It is a partial expanded schematic longitudinal cross-sectional view which shows the gas generator and piston of the actuator which are other embodiment of this invention. FIG. 13 is a partial enlarged cross-sectional view showing a state where the squib of the gas generator is activated in the actuator of FIG. 12.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 3, an actuator A1 according to the embodiment is a hood flip-up device (hereinafter referred to as a safety device for automobiles) mounted on a vehicle V. Abbreviated as “bounce device”). The flip-up device U is disposed on the rear end 10c side of the hood panel 10, and is configured to flip up the rear end 10c of the hood panel 10 when the actuator A1 is operated. In the case of the embodiment, the front bumper 5 of the vehicle V is provided with a sensor 6 capable of detecting or predicting a collision with a pedestrian as shown in FIG. When an operating circuit (not shown) detects or predicts a collision between the vehicle V and a pedestrian based on a signal from the sensor 6, the gas generator 42 (see FIG. 8) of the actuator A1 is operated. It is configured.

  As shown in FIGS. 1 and 2, the hood panel 10 is disposed so as to cover the upper part of the engine room ER in the vehicle V, and is a hinge portion 11 disposed in the vicinity of the rear end 10 c on both edges in the left-right direction. Thus, the vehicle V is connected to the body 1 side of the vehicle V so that it can be opened and closed by a front opening. The hood panel 10 is made of sheet metal made of aluminum (aluminum alloy) or the like, and as shown in FIG. 3, an outer panel 10a on the upper surface side, an inner panel 10b that is positioned on the lower surface side and has higher strength than the outer panel 10a, It is composed of The food panel 10 is configured to be plastically deformable so that it can absorb the kinetic energy of the pedestrian when receiving the pedestrian. In the embodiment, when the vehicle V collides with the pedestrian, the actuator A1 is actuated to push up the rear end 10c of the hood panel 10 as shown in FIG. Since the deformation space DS can be formed between the engine room ER and the engine room ER, the amount of plastic deformation during plastic deformation can be increased. Furthermore, in the case of the embodiment, the shaft portion 65 of the support rod 64 that has moved the rear end 10c of the hood panel 10 upwardly is bent and plastically deformed with the downward movement of the hood panel 10 when receiving the pedestrian. (See the two-dot chain line in FIG. 4). Therefore, in the case of the embodiment, even if the kinetic energy of the pedestrian is large, a large amount of kinetic energy of the pedestrian is absorbed by the plastic deformation of the hood panel 10 itself and the bending plastic deformation of the shaft portion 65 of the support rod 64. Can do.

  The hinge portion 11 is disposed on the left edge 10d and the right edge 10e on the rear end 10c side of the hood panel 10 (see FIGS. 1 and 2), and is connected to the hood ridge rein hose 2 on the body 1 side, respectively. The hinge base 12 is fixed to the flange 2a, and the hinge arm 14 is fixed to the hood panel 10 (see FIGS. 2 and 3). As shown in FIG. 3, each hinge arm 14 is configured as a shape in which a sheet metal angle member is bent in a substantially semicircular arc shape so as to protrude downward, and a base end 14 a on the hinge base 12 side is supported. The shaft 13 is connected to the hinge base 12 so as to be rotatable. Moreover, each hinge arm 14 is set as the structure provided with the connection board part 15 extended along the lower surface of the food | hood panel 10 from the front-end | tip 14b in the front-end | tip 14b side which leaves | separates from the base part end 14a. The panel 10 is joined to the lower surface side of the rear end 10c by welding or the like. In addition, a notch recess 14c is formed in the vicinity of the tip 14b of the hinge arm 14 so that the lower edge is notched in a substantially circular shape. The area around the notch recess 14c is the area around the actuator A1. In operation, when the support rod 64 pushes up the rear end 10c of the hood panel 10, the plastic deformation portion 14d is plastically deformed, and the hood panel 10 is allowed to rise (see FIGS. 3 and 4).

  The support shafts 13 are arranged so that their axial directions are along the left-right direction of the vehicle V. When the hood panel 10 is opened, as shown by a two-dot chain line from the solid line in FIG. 3, the front end 10 f of the hood panel 10 along with the distal end 14 b side of each hinge arm 14 with the left and right support shafts 13 as the rotation center. If the side (refer FIG. 1) is raised by front opening, the food panel 10 can be opened by front opening. By the way, when the rear end 10c of the hood panel 10 is raised, the front end 10f side of the hood panel 10 is separated from the body 1 side by a latch mechanism for locking a hood lock striker (not shown) for normal closing arranged at the front end 10f. It will not come off.

  As shown in FIGS. 2 and 3, a cowl 7 including a highly rigid cowl panel 7a on the body 1 side and a synthetic resin cowl louver 7b above the cowl panel 7a is disposed behind the hood panel 10. It is installed. The cowl louver 7b is disposed so that the rear end side is connected to the lower portion 3a side of the front windshield 3. Further, as shown in FIGS. 1 and 2, front pillars 4 and 4 are disposed on the left and right sides of the front windshield 3.

  As shown in FIGS. 3 and 4, the flip-up device U is disposed in the vicinity of the left and right hinge portions 11 in the hood panel 10, and is an actuator A <b> 1 disposed below the rear end 10 c of the hood panel 10. And a receiving seat 16 disposed on the hood panel 10 side above the actuator A1 corresponding to each actuator A1. In the case of the embodiment, the receiving seat 16 is configured from the lower surface of the connecting plate portion 15 provided on the front end 14b side of the hinge arm 14 disposed on the lower surface of the rear end 10c of the hood panel 10.

  2 and 3, the actuator A1 of the embodiment is held by a mounting bracket 18 having a substantially U-shaped cross section that is bolted to a mounting flange 2b connected to the hood ridge rein hose 2, It is arrange | positioned under each hinge part 11 used as the downward direction of the left edge 10d and the right edge 10e in the rear end 10c side of the food panel 10 (refer FIGS. 1-3). As shown in FIG. 5, each actuator A <b> 1 is a piston cylinder type that uses a working gas G generated when the gas generator 42 is actuated as a drive source. A gas generator 42 that is disposed in the cylinder 22 and generates a working gas G during operation; a piston 54 slidably housed in the cylinder 22; a support rod 64 coupled to the piston 54; And a lock mechanism R that regulates the backward movement (downward movement in the embodiment) of the support rod 64 that has moved (upward movement in the case of the embodiment). In the embodiment, as shown in FIG. 7, the lock mechanism R includes a locking ring 61, a storage groove 59 that is provided on the outer peripheral side of the piston 54 and stores the locking ring 61, and an inner peripheral surface of the cylinder 22. And a locking step portion 26 that is provided at 24a and that locks the part of the locking ring 61 by entering a part thereof.

  The cylinder 22 is disposed so that the axial direction thereof is substantially along the vertical direction. As shown in FIG. 5, the piston 22 is disposed between the top end wall portion 31 on the upper end side and the original end wall portion 38 on the lower end side. A cylindrical main body 23 for sliding 54 is disposed. The cylinder 22 is configured by connecting caps 30 and 37 to the upper and lower sides of a steel pipe member 29 constituting the main body 23, and the tip wall portion 31 is provided on the outer peripheral surface on the upper end side of the pipe member 29. The cap 30 is screwed and coupled to the male screw 29a, and the base end wall portion 38 is screwed to and coupled to the male screw 29b provided on the outer peripheral surface of the lower end side of the pipe member 29. 37.

  The main body 23 has a sliding hole 24 having a substantially circular opening in the cross-sectional shape in the direction perpendicular to the axis corresponding to the outer shape of the piston 54 extending vertically, and when the actuator A1 is operated, the piston 54 is Then, it slides on the inner peripheral surface 24a of the sliding hole 24 and moves upward (moves forward).

  In the cylinder 22, in the vicinity of the tip wall 31 in the main body 23, the diameter is larger than the inner peripheral surface (the inner peripheral surface 24 a of the sliding hole 24) of the main body 23 that slides the piston 54 as shown in FIG. 6. A recessed step 26 that is recessed is formed. The locking step portion 26 constitutes a locking mechanism R, and is disposed in the vicinity of a locking ring 61 (described later) after the piston 54 has moved upward (after forward movement), so that the locking ring 61 moves backward (lowers). This is a part that regulates movement), and is provided with a locking regulating surface 27 and an outer circumferential regulating surface 28. In the case of the embodiment, the latching restriction surface 27 is constituted by the upper end surface 29c of the pipe material 29, and is capable of regulating the downward movement (retreating movement) of the locking ring 61 constituting the lock mechanism R. It is comprised so that it may contact | abut to the site | part (backward side surface) of the ring 61 at the back movement side (refer B, C of FIG. 7). In the case of the embodiment, the outer peripheral restriction surface 28 is configured by an inner peripheral surface 33a of a storage recess 33 (to be described later) in the cap 30, and from the outer peripheral edge of the locking restriction surface 27 to the axial direction of the main body portion 23 (the piston 54). It is configured to extend along the forward movement direction) and to come into contact with the outer peripheral surface of the locking ring 61 whose diameter has been enlarged when the locking ring 61 is restricted from moving backward (see FIGS. 7B and 7C). ).

  As shown in FIGS. 5 and 6, the cap 30 disposed on the upper end side of the main body portion 23 in the cylinder 22 includes a front end wall portion 31 that closes the upper end of the cylinder 22, and a lower end side (the pipe material 29 side) of the front end wall portion 31. ) And a substantially cylindrical peripheral wall portion 35 extending downward. On the inner peripheral surface of the peripheral wall portion 35, a female screw 35a that is screwed into a male screw 29a provided on the pipe member 29 is formed. The distal end wall portion 31 has a substantially cylindrical shape, and includes an insertion hole 32 penetrating along the vertical direction so that the shaft portion 65 of the support rod 64 can be inserted in the center, and is moved upward ( A storage recess 33 for storing the piston 54 after the forward movement) is provided. The insertion hole 32 is configured so that the inner diameter dimension D1 is slightly larger than the outer diameter dimension D2 of the shaft portion 65 of the support rod 64, and a gap is provided between the insertion hole 32 and the shaft portion 65 (see FIG. 6). . The gap between the shaft portion 65 in the insertion hole 32 allows air between the piston 54 and the cylinder 22 to be released to the outside during operation, and allows the piston 54 to smoothly move forward (upward movement). After the upward movement (forward movement) of the piston 54, the working gas G filled in the cylinder 22 is discharged to the outside. Note that a recess 32 a is formed on the upper end side of the insertion hole 32, the periphery of which is cut out in a tapered shape. The concave portion 32a is disposed on the outer peripheral side of the upper end of the shaft portion 65 of the support rod 64, and accommodates an O-ring 67 for ensuring airtightness before operation in a vehicle-mounted state.

  After the ascending movement (forward movement), the storage recess 33 locks the locking ring 61 with the locking restricting surface 27 so that the piston 54 in a state where the downward movement (retreating movement) is restricted can be stored inside. In this configuration, a portion near the lower end of the inner peripheral surface 33a constitutes an outer peripheral regulating surface 28 that comes into contact with the outer peripheral surface of the enlarged locking ring 61. The housing recess 33 is set to a dimension that allows the inner diameter dimension to be larger than the inner diameter dimension of the sliding hole 24 and to contact the outer peripheral surface of the expanded locking ring 61. Further, a C ring 34 for restricting the vertical movement of the support rod 64 (piston 54) before operation is disposed on the upper surface 33b side in the housing recess 33 so as to contact the upper surface 33b (see FIG. (See FIG. 6). The C-ring 34 is locked in a concave groove 65a formed in the shaft portion 65 of the support rod 64 to prevent the support rod 64 (piston 54) before operation from moving in the vertical direction, and to generate gas. When the piston 42 is strongly pushed up by the working gas G during the operation of the device 42, the locked state with the concave groove 65a is released and the upward movement of the piston 54 is allowed.

  As shown in FIGS. 5 and 8, the cap 37 disposed on the lower end side of the main body portion 23 in the cylinder 22 is a substantially disc-shaped base end wall portion disposed so as to close the lower end side of the main body portion 23. 38 and a substantially cylindrical peripheral wall 39 extending upward from the outer peripheral edge of the base end wall 38. An insertion hole 38a through which a terminal 43c of a squib 43 (to be described later) of the gas generator 42 can be inserted is formed in the base end wall 38, and a peripheral portion of the insertion hole 38a and a lower side of the peripheral wall 39 are provided. The gas generator 42 is attached to the base end wall 38 and is disposed in the cylinder 22 using the portion. The peripheral wall 39 is provided with a female screw 39a screwed to a male screw 29b provided on the pipe member 29 on the inner peripheral surface on the upper end side, and the cap 37 is in a state where the gas generator 42 is attached to the base end wall 38. Thus, the female screw 39 a is screwed into the male screw 29 b and is attached to the main body 23.

  As shown in FIG. 8, the gas generator 42 includes a housing 47 filled with a gas generating agent 46 that generates a working gas during combustion, and a squib 43 that can ignite the gas generating agent 46. I have. In the case of the embodiment, the gas generator 42 arranges the housing 47 and the squib 43 in series along the axial direction of the cylinder 22 while a later-described ceiling wall 49 of the housing 47 faces the piston 54. And disposed in the cylinder 22.

  The squib 43 has a substantially cylindrical ignition part 43a disposed on the upper side (piston 54 side) so as to face the gas generating agent 46, and is disposed on the lower side of the ignition part 43a and has a larger diameter than the ignition part 43a. Flange portion 43b, and a terminal 43c that is disposed below the flange portion 43b and has a smaller diameter than the flange portion 43b. The terminal 43 c is configured to be dimensioned so as to be inserted into an insertion hole 38 a formed in the base end wall 38 of the cap 37 and exposed from the base end wall 38. As shown in FIG. 8, the terminal 43c of the squib 43 is connected to a lead wire 44 extending from a control device (not shown) of the vehicle. The squib 43 is configured to receive an operation signal from the control device (not shown) and operate to generate a flame from the ignition unit 43a to burn the gas generating agent 46 filled in the housing 47. .

  The gas generating agent 46 is formed by molding a predetermined chemical capable of generating the working gas G at the time of combustion into a predetermined shape. In the case of the embodiment, the gas generating agent 46 has a substantially spherical shape. And the squib 43 are filled in the gap.

  The housing 47 has a substantially cylindrical peripheral wall 48 configured to extend from the squib 43, and a substantially disk-shaped ceiling wall configured to close the distal end side (the upper end side and the piston 54 side) of the peripheral wall 48. 49. The housing 47 is formed so that the center thereof coincides with the central axis C <b> 1 (see FIG. 5) of the cylinder 22. And in the case of embodiment, the surrounding wall 48 is comprised from the large diameter part 48a by the side of a base part, and the small diameter part 48b by the side of the front end made smaller diameter than the large diameter part 48a (refer FIG. 8). In the case of the embodiment, the housing 47 is made of a metal such as an aluminum alloy, and the base portion side (lower end side) of the large diameter portion 48 a in the peripheral wall 48 is connected to the flange portion 43 b of the squib 43. It is integrated with the squib 43.

  The ceiling wall 49 is configured as a substantially circular shape that closes the distal end side (upper end side) of the small diameter portion 48b in the peripheral wall 48, and the outer diameter dimension is set to the outer diameter dimension D3 of the small diameter portion 48b (see FIG. 9). It is set as the structure matched. The ceiling wall 49 is disposed to face a bottom surface portion 55 to be described later of the piston 54 before the operation, and when the squib 43 is operated, the rupture planned portion 51 disposed around is ruptured and positioned near the center. It is set as the structure which has the some door part 50 opened as the front-end | tip 50a side at the time of opening. In the case of the embodiment, the planned break portion 51 has a plurality of locations (six in the case of the embodiment) as linearly extending from the center C2 of the ceiling wall 49 (coincident with the center axis C1 of the cylinder 22, see FIG. 10). ) And the door portion 50 is configured to open radially. In the case of the embodiment, the planned fracture portion 51 is configured such that a cut having a depth of about ½ of the wall thickness is continuously provided in the ceiling wall 49 from the inner surface side (see FIG. 9). The door part 50 is comprised from the site | part between this fracture | rupture planned part 51, and in the case of embodiment, it is set as the structure which is made into six sheets made into substantially the same substantially triangular plate shape, and opens radially. . Each door portion 50 is opened radially so that the front end 50a located near the center before opening is separated from each other with the vicinity of the boundary portion with the peripheral wall 48 (on the side of the original portion 50b) as the rotation center when opening. (See the two-dot chain line in FIGS. 9 and 10). Specifically, each door 50 is opened so that the tip 50a side near the center faces the piston 54 side. In the case of the embodiment, each door portion 50 is opened so that the front end 50 a enters a later-described recess 56 formed in the bottom surface portion 55 of the piston 54. Specifically, each door portion 50 operates with a length L1 in the direction perpendicular to the axis before opening (approximately equal to 1/2 of the outer diameter D3 of the small diameter portion 48b in the peripheral wall 48, see FIG. 9). It is configured to be larger than the separation distance W1 between the surface of the ceiling wall 49 of the front gas generator 42 and the surface of the bottom surface 55 of the piston 54 (see FIGS. 8 and 9).

  The piston 54 has a substantially cylindrical shape having an outer diameter that is slidable with respect to the inner peripheral surface 24a of the sliding hole 24 in the main body 23 of the cylinder 22, and is a lower surface on the gas generator 42 side. A concave portion 56 is provided in the vicinity of the center of the bottom surface portion 55 on the side so as to dent the surface upward toward the support rod 64 side. The piston 54 is disposed in the cylinder 22 so that the bottom surface portion 55 is positioned in the vicinity of the ceiling wall 49 of the gas generator 42 in a state before operation. As described above, the separation distance W1 between the bottom surface portion 55 of the piston 54 and the ceiling wall 49 of the gas generator 42 is set to be smaller than the length L1 of each door portion 50 of the gas generator 42. Specifically, the separation distance W1 is set to about 1/3 of the length dimension L1. The separation distance W1 between the bottom surface portion 55 of the piston 54 and the ceiling wall 49 of the gas generator 42 is not preferable even if it is too small, and the working gas G filled inside at the start of the inflow of the working gas G in the initial stage of operation. Therefore, it is desirable to set so that the piston 54 can smoothly start moving forward.

  The recess 56 formed in the bottom surface portion 55 matches the center C3 with the center axis C1 of the cylinder 22 (matches the center axis of the piston 54), that is, the center C2 of the ceiling wall 49 in the housing 47 of the gas generator 42. The opening width dimension W2 (see FIG. 8) is configured to be smaller than the outer diameter dimension of the ceiling wall 49 (substantially coincident with the outer diameter dimension D3 of the peripheral wall 48). Specifically, the opening width dimension W2 of the recess 56 is set to about ½ of the outer diameter dimension of the ceiling wall 49 (the outer diameter dimension D3 of the peripheral wall 48). In other words, each door portion 50 formed on the ceiling wall 49 is located outside the inner peripheral surface 57a of the peripheral wall portion 57 that constitutes the outer peripheral edge of the concave portion 56, with the portion on the side of the original portion 50b serving as the rotation center when opened. It is comprised so that it may be located in the direction. And in embodiment, since the door part 50 opens so that the front-end | tip 50a may approach in the recessed part 56, the surrounding wall part 57 which comprises the periphery of the recessed part 56 in the bottom face part 55 is the opening of each door part 50 opened. It overlaps with the front end 50a on the radially outward side from the central axis of the piston 54 (coincident with the central axis C1 of the cylinder 22). Furthermore, in the embodiment, the inner peripheral surface 57a of the peripheral wall portion 57 comes into contact with the tip 50a of each opened door portion 50, and also serves as a stopper that restricts the opening of the door portion 50. In the case of the embodiment, the concave portion 56 formed in the bottom surface portion 55 is fitted with a hexagon wrench used to fasten the head portion 66 to the upper end side of a shaft portion 65 described later in the support rod 64 extending from the piston 54. In order to fit, a hexagonal wrench can be fitted into the hexagonal column. The depth of the concave portion 56 in the bottom surface portion 55 (the volume of the concave portion 56) is a depth at which the piston 54 can be smoothly started to move forward by the working gas G filled inside when the working gas G starts to flow in the initial stage of operation. (Volume) is set.

  In the actuator A1 of the embodiment, the length dimension L1 of each door portion 50 is set to approximately three times the separation distance W1 between the bottom surface portion 55 of the piston 54 and the ceiling wall 49 of the gas generator 42. At the time of opening, the front end 50a is caused to enter a recess 56 formed in the bottom surface portion 55, and the recess 56 has an opening width dimension W2 that is an outer diameter dimension of the ceiling wall 49 (an outer diameter dimension of the peripheral wall 48). It is set to about 1/2 of D3). In other words, the opening width dimension W <b> 2 of the recess 56 is configured to substantially match the length dimension L <b> 1 of each door part 50. When each door portion 50 is opened, the front end 50a that has entered the recess 56 is brought into contact with the inner peripheral surface 57a (the side surface of the recess 56) of the peripheral wall portion 57 that forms the periphery of the recess 56. Thus, the opening that directs the tip 50a outward in the radial direction is stopped, and in the case of the embodiment, the inclination angle θ with respect to the horizontal direction (the direction perpendicular to the central axis C1 of the cylinder 22) ( 11) is about 45 °, and the opening is instantaneously stopped.

  As shown in FIGS. 7 and 8, a fitting groove 58 for fitting the O-ring 62 is formed on the outer peripheral surface 54 a of the piston 54 on the bottom surface 55 side, and above the fitting groove 58 away from the bottom surface 55. In addition, a storage groove 59 capable of storing the locking ring 61 is formed. The storage groove 59 constitutes the lock mechanism R, and allows the piston 54 to move upward (forward movement) with the locking ring 61 stored, and after the piston 54 moves upward (forward movement). In FIG. 3, the engagement step portion 26 is configured to be able to maintain the engagement state with the engagement restriction surface 27 of the engagement ring 61 whose diameter is increased so as to contact the outer periphery restriction surface 28 (see FIG. 7). In other words, the storage groove 59 is configured to prevent the locking ring 61 whose diameter has been enlarged from returning after the upward movement (forward movement) of the piston 54.

  The locking ring 61 constituting the locking mechanism R is formed by bending a wire rod made of spring steel having a circular cross section into an annular shape (substantially C-shaped). In this state, the piston 54 is stored in a storage groove 59 provided in the piston 54, and is restored and expanded so as to come into contact with the outer peripheral regulating surface 28 of the locking step portion 26 after the piston 54 moves upward (forward movement). It is set as the structure by which it is diameter.

  The O-ring 62 is made of a rubber-like elastic body, and is configured so that the outer peripheral surface is in sliding contact with the inner peripheral surface 24 a of the sliding hole 24 in the cylinder 22 while being accommodated in the fitting groove 58. Has been. The O-ring 62 improves the airtightness between the piston 54 and the main body 23 of the cylinder 22, and the operating gas G leaks between the piston 54 and the main body 23 when the gas generator 42 is operated. In the case of the embodiment, it is made of silicon rubber having good heat resistance.

  The support rod 64 includes a round bar-shaped shaft portion 65 disposed along the axial direction (vertical direction) of the cylinder 22 and a head portion 66 disposed on the upper end side of the shaft portion 65. In the embodiment, the shaft portion 65 is configured integrally with the piston 54 so as to extend from the piston 54. In the case of the embodiment, the head portion 66 is constituted by a cap nut that is separated from the shaft portion 65 and fastened to the upper end side of the shaft portion 65. A concave groove 65a capable of locking the C-ring 34 disposed in the storage concave portion 33 formed in the cap 30 is formed in the vicinity of the upper end of the shaft portion 65 (see FIG. 5). In addition, an O-ring 67 is fitted to a boundary portion between the shaft portion 65 and the head portion 66 in the support rod 64. The O-ring 67 is housed in a recess 32a formed on the upper end side of the insertion hole 32 provided in the distal end wall portion 31 of the cap 30 before operation (see FIG. 5). The O-ring 67 is made of a rubber-like elastic body, and is disposed in order to ensure airtightness in the cylinder 22 before operation in a vehicle-mounted state. Specifically, in the case of the embodiment, the O-ring 67 is formed from a general-purpose rubber material such as chloroprene rubber.

  In the flip-up device U of the embodiment, when the operation circuit (not shown) detects or predicts a collision between the vehicle V and the pedestrian by a signal from the sensor 6, the gas generator 42 in the actuator A1 is operated. As shown in FIG. 5, the generated working gas G pushes up the piston 54 in the main body 23 of the cylinder 22, causing the head 66 of the support rod 64 to abut the lower surface of the receiving seat 16, The rear end 10c of the hood panel 10 is raised so as to widen the gap with the lower cowl 7. Then, as shown in FIG. 4, the rear end 10c of the moved hood panel 10 is supported by the head 66 of the support rod 64, and the pedestrian moving obliquely rearward and downward from above is supported. If it is received, the kinetic energy F of the pedestrian is received, and the rear end 10c of the hood panel 10 moves downward while being plastically deformed, and the head 66 is placed on the receiving seat 16 as the hood panel 10 moves downward. The shaft portion 65 of the supporting rod 64 in contact with the support rod 64 is bent and plastically deformed so that the head 66 on the upper end side is directed rearward while absorbing the kinetic energy F of the pedestrian (FIG. 4). (See the two-dot chain line).

  In the actuator A1 of the embodiment, when the squib 43 of the gas generator 42 is ignited at the time of operation, the planned fracture portion 51 formed on the ceiling wall 49 of the housing 47 filled with the gas generating agent 46 is broken. Then, the door part 50 opens radially, and the working gas G generated by burning the gas generating agent 46 flows out into the cylinder 22. Then, the piston 54 accommodated in the cylinder 22 is pushed by the working gas G and moves forward (upward movement) together with the support rod 64. Further, in the actuator A1 of the embodiment, in the housing 47 of the gas generator 42, the ceiling wall 49 on which the planned fracture portion 51 is disposed is disposed to face the bottom surface portion 55 of the piston 54 before operation, The bottom surface portion 55 of the piston 54 has a concave portion 56 that is recessed in the vicinity of the center, and the peripheral edge of the concave portion 56 is formed while the front end 50a when the door portion 50 is opened enters the concave portion 56. The inner wall surface 57 a of the peripheral wall portion 57 is configured to be able to come into contact with the inner wall surface 57 a. Therefore, if the door part 50 is opened during operation, the door part 50 is opened with the tip 50a entering the recess 56, so that the space S between the gas generator 42 and the bottom surface part 55 of the piston 54 is opened. A mode in which the axially orthogonal direction side is covered over substantially the entire surface (substantially the entire circumference) by the door portion 50 and the recess portion 56 (the peripheral wall portion 57 constituting the periphery of the recess portion 56) provided in the bottom surface portion 55 of the piston 54. (See FIG. 11), the working gas G generated by the combustion of the gas generating agent 46 is in the direction perpendicular to the axis, in other words, the inner peripheral surface of the cylinder 22 (the inner peripheral surface 24a of the sliding hole 24). ), The flow is suppressed toward the bottom side 55 of the piston 54 and the flow is directed toward the bottom surface 55 of the piston 54.

  At this time, in the actuator A1 of the embodiment, the distal end 50a of the opened door portion 50 is in contact with the inner peripheral surface 57a of the peripheral wall portion 57 constituting the peripheral edge in the concave portion 56. A region (space S) surrounded by the door portion 50 and the bottom surface portion 55 (recessed portion 56) of the piston 54 is filled with the working gas G, and the internal pressure in the space S can be quickly increased. The pressing force of the gas G can be instantaneously applied to the bottom surface portion 55 (the upper surface (ceiling surface) 56a in the recess 56) along the moving direction of the piston 54. As a result, the pressing force of the working gas G can be instantaneously applied to the bottom surface portion 55 of the piston 54, and the piston 54 can be rapidly moved forward.

  Therefore, in the actuator A1 of the embodiment, the piston 54 can be rapidly moved forward during operation.

  In the actuator A1 of the embodiment, if the contact state of the distal end 50a of the opened door portion 50 with the inner peripheral surface 57a of the peripheral wall portion 57 is released as the piston 54 moves forward, the door portion 50 is The tip 50a is greatly opened so as to face the direction perpendicular to the axis.

  In particular, in the actuator A1 of the embodiment, since the concave portion 56 is provided in the vicinity of the center of the bottom surface portion 55 of the piston 54 so as to make the surface concave, the bottom surface that receives the pressing force of the working gas G is provided. A wide pressure receiving area of the portion 55 can be secured. Specifically, in the actuator A1 of the embodiment, at the beginning of operation, the pressing force of the working gas G hardly acts on the peripheral portion of the concave portion 56 in the bottom surface portion 55, and the upper surface (ceiling surface) of the concave portion 56. ) 56 a and only a part of the inner peripheral surface 57 a of the peripheral wall portion 57, but the piston 54 moves forward (moves upward), and the inner peripheral surface of the peripheral wall portion 57 in the concave portion 56 of the door portion 50. When the contact state with 57a is released, the entire space surrounded by the piston 54 and the main body portion 23 of the cylinder 22 is filled with the working gas G, and the pressing force of the working gas G is reduced to the bottom surface. It acts on the peripheral portion of the concave portion 56 in the portion 55 and the entire side surface (inner peripheral surface 57a of the peripheral wall portion 57) and upper surface (ceiling surface) 56a of the concave portion 56. Therefore, compared with the case where a recessed part is not provided, the pressure receiving area of a bottom face part can be ensured widely, and piston 54 can be moved forward (upward movement) rapidly.

  Moreover, in actuator A1 of embodiment, since it is the structure which makes the front-end | tip 50a approach into the recessed part 56 at the time of opening the door part 50, the opened door part 50 entered the front-end | tip 50a side in the recessed part 56. It becomes an aspect which comprises a guide cylinder. Therefore, the generated working gas G can be surely flown out into the recess 56, and the pressing force of the working gas G can be applied to the bottom surface 55 of the piston 54 (the upper surface 56b of the recess 56) without waste. Can act.

  Furthermore, in actuator A1 of embodiment, the door part 50 formed in the ceiling wall 49 arrange | positions the linear fracture | rupture planned part 51 extended substantially radially from the center C2 of the ceiling wall 49 at the periphery, and is the time of opening. Since the outer shape is substantially the same triangular plate shape and is configured to open radially, the open door portion 50 causes the space S between the gas generator 42 and the bottom surface portion 55 of the piston 54 to be orthogonal to the axis. The side can be covered substantially uniformly over substantially the entire surface (entire circumference). Therefore, the pressing force of the working gas G can be applied to the substantially circular area with the center of the bottom surface portion 55 as a reference with respect to the bottom surface portion 55 of the piston 54. It becomes possible to move the piston 54 forward (upward movement). Of course, if such a point is not considered, the shape of the door portion and the shape of the planned fracture portion are not limited to this as long as each door portion is configured to open a portion near the center as the tip side. For example, it is good also as a structure which provides a substantially H-shaped fracture | rupture scheduled part in a ceiling wall, and opens the area | region enclosed by a fracture | rupture scheduled part as a door part.

  Furthermore, in the actuator A1 of the embodiment, each door portion 50 formed on the ceiling wall 49 has a portion on the side of the original portion 50b serving as a rotation center at the time of opening the outer peripheral edge of the concave portion 56 (the inner periphery of the peripheral wall portion 57). It is configured to be positioned outward from the surface 57a), and is configured to allow the tip 50a to enter the recess 56 when opened. Therefore, in the actuator A1 of the embodiment, each door portion 50 at the time of opening has an opening angle of less than 90 °, and the tip 50a is connected to the inner peripheral surface 57a (shaft of the peripheral wall portion 57 constituting the outer peripheral edge of the recess 56. The side surface on the orthogonal direction side). As a result, in the actuator A1 of the embodiment, each door portion 50 is suppressed from opening at a large opening angle, and a gap generated between the door portions 50 at the time of opening can be reduced as much as possible. It is possible to suppress the leakage of the working gas G from the gap as much as possible, and to efficiently move the piston 54 forward (upward movement) at the beginning of the operation. Of course, if such a point is not taken into consideration, the opening width dimension of the recess is substantially the same as the outer diameter dimension of the ceiling wall or the outer diameter of the ceiling wall, even in the configuration in which the recess is disposed on the bottom surface. You may comprise so that it may become larger than a dimension.

  Furthermore, in the actuator A1 of the embodiment, the outer peripheral surface 54a of the piston 54 is slidably brought into contact with the inner peripheral surface of the cylinder 22 (the inner peripheral surface 24a of the sliding hole 24 in the main body portion 23). Since the O-ring 62 is disposed, the airtightness between the piston 54 and the cylinder 22 can be improved, and the piston 54 and the cylinder 22 are moved before the piston 54 is moved during operation. Therefore, the operating gas G can be prevented from leaking out, and the piston 54 can be rapidly moved forward. Further, the O-ring 62 is arranged on the outer peripheral surface 54a side of the piston 54 and is arranged in the vicinity of the gas generator 42 in a state before operation, but in the actuator A1 of the embodiment, the gas generator Since the operating gas G generated in the initial stage of the operation 42 can be prevented from moving toward the inner peripheral surface side (the inner peripheral surface 24a of the sliding hole 24) of the cylinder 22 on the side perpendicular to the axis, this operation is performed. Initially, it is possible to suppress the hot working gas G from hitting the O-ring 62 as much as possible, and it is possible to suppress the deterioration of the O-ring 62 that reduces the airtightness between the piston 54 and the cylinder 22. .

  Further, in the embodiment, when the door portion 50 formed on the housing 47 of the gas generator 42 is opened, the inner peripheral surface 57a of the peripheral wall portion 57 constituting the peripheral edge of the concave portion 56 formed on the bottom surface portion 55 of the piston 54. However, the actuator A2 may be configured as shown in FIG. In the actuator A2 of FIG. 12, the opening width W3 of the recess 56A formed in the bottom surface portion 55A of the piston 54A is larger than the outer diameter D4 of the ceiling wall 49A in the gas generator 42A, and the bottom surface portion 55A of the piston 54A. And the separation distance W4 between the gas generator 42A and the ceiling wall 49A is also set large. Specifically, when the door portion 50A is opened, the tip 50a can enter the recess 56A, but the tip 50a that has entered the recess 56A constitutes the periphery of the recess 56A. It is set as the structure which is not made to contact | abut with the internal peripheral surface 57a of 57 A of surrounding wall parts.

  Even when such an actuator A2 is used, if the door portion 50A is opened during the operation of the gas generator 42A, the space between the gas generator 42A and the bottom surface portion 55A of the piston 54A is opened. And the bottom surface portion 55A of the piston 54A, the axial orthogonal direction side is covered over substantially the entire surface (substantially the entire circumference) (see FIG. 13). In this actuator A2, as shown in FIG. 13, the inner peripheral surface 57a of the peripheral wall portion 57A constituting the peripheral edge of the concave portion 56A formed in the bottom surface portion 55A of the piston 54A is temporarily opened. It is the structure which has overlapped with the front end 50a of 50A on the outward side of the radial direction from the central axis of piston 54A. Therefore, at the time of overlapping immediately after operation, the operating gas G flows from the gap between the opened door portion 50A and the upper surface 56a (ceiling surface) of the concave portion 56A so as to go outward in the radial direction. In addition, since the peripheral wall portion 57A constituting the periphery of the recessed portion 56A covers the outer side of the tip 50a of the opened door portion 50A, the operation is performed in the region overlapping the opened door portion 50A in the recessed portion 56A. The working gas G is filled, and the pressing force of the filled working gas G can be instantaneously applied to the bottom surface 55A along the moving direction of the piston 54A. As a result, even with the actuator A2 having such a configuration, the pressing force of the working gas G can be instantaneously applied to the bottom surface portion 55A of the piston 54A, and the piston 54A can be rapidly moved forward. it can. Also in the actuator A2 having such a configuration, if the overlapping state of the distal end 50a of the opened door portion 50A with the inner peripheral surface 57a of the peripheral wall portion 57A is released as the piston 54A moves forward, the door portion 50A will open widely so that the front-end | tip 50a may face the axis orthogonal direction side.

  Furthermore, in the actuators A1 and A2 of the embodiment, the case where the forward movement is increased and the backward movement is decreased is shown. However, the operation direction is not limited to this, for example, in the horizontal operation direction. The actuator of the present invention may be used. The automobile safety device in which the actuator of the present invention is used may be other than the flip-up device U that raises the hood panel 10. For example, the present invention may be applied to an actuator of a knee protection device as an automobile safety device that receives a knee of a driver or a passenger seated on a passenger seat with a knee panel.

10 ... Food panel,
22 ... Cylinder,
42, 42A ... gas generator,
47, 47A ... housing,
49, 49A ... ceiling wall,
50, 50A ... door part,
50a ... tip,
51 ... planned fracture part,
54, 54A ... piston,
55, 55A ... bottom surface,
56, 56A ... recess,
57, 57A ... peripheral wall,
57a ... inner peripheral surface,
64 ... support rod,
G: Working gas,
U ... Hood jumping device,
A1, A2 ... Actuators.

Claims (4)

Used in automotive safety equipment,
A piston cylinder type actuator that moves a piston arranged in the cylinder together with a support rod connected to the piston by a working gas generated from a gas generator provided in a cylindrical cylinder,
The gas generator includes a housing filled with a gas generating agent that generates the working gas during combustion, and a squib that can ignite the gas generating agent.
In the housing, the ceiling wall that is disposed to face the bottom surface of the piston before operation, when the squib is operated, breaks a planned break portion that is disposed around, and a portion located near the center, It is configured to have a plurality of doors that open as the tip side when opening,
The bottom surface portion of the piston has a concave portion that dents the surface near the center, and when the door portion is opened, the front end of the door portion enters the concave portion, The front end can be contacted, or the peripheral wall portion constituting the peripheral edge of the recess in the bottom surface portion can be overlapped with the front end of each door portion on the outer side in the radial direction from the central axis of the piston, An actuator characterized by being configured.   2. The actuator according to claim 1, wherein the door portions formed on the ceiling wall are configured to open radially with substantially the same outer shape when opened.   Each door part formed in the ceiling wall is configured to position a part on the base part side that becomes a rotation center when opening from the outer peripheral edge of the recess. The actuator according to 1 or 2.   The O-ring which consists of a rubber-like elastic body is arrange | positioned at the outer peripheral surface of the said piston, and is slidably contacted with the said cylinder internal peripheral surface, The one of Claim 1 thru | or 3 characterized by the above-mentioned. Actuator.

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