Actuator

Abstract

To provide an actuator capable of easily adjusting pressing force of a piston rod when operated.SOLUTION: In an actuator, a piston part 41 of a piston rod 40 moves forwards a rod part 52 extending through a ceiling part of a cylinder to move a pressed part on which a tip part of the rod part abuts by using work gas G comprising combustion gas generated when a gas generator 38 disposed on a bottom part 36 of the cylinder 22 is operated. A restriction part 28 including a gas insertion hole 29 that has an opening diameter d1 smaller than an opening diameter d2 of a sliding inner peripheral surface 26a of the piston part and through which the work gas passes is provided between the piston part before operation and the gas generator in the cylinder. The piston part includes: a body part 42 sliding on an inner peripheral surface of the cylinder when operated; and a fitting insertion part 46 protruding from the body part and fitted and inserted to the gas insertion hole so as to be detachable from the gas insertion hole when the work gas of the gas generator is discharged.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an actuator that generates operating gas from combustion gas when activated, and relates to an actuator that is suitably used for automobile safety devices mounted on vehicles, such as a hood lift-up device that lifts the hood panel of a vehicle when catching a pedestrian. [Background technology]

[0002] Among conventional actuators of this type, there is one used in a hood lift-up device that lifts a hood panel, and it is configured as a piston cylinder type that uses combustion gas generated by igniting a gas generator when it is activated as the working gas (for example, see Patent Document 1). In this actuator, the piston rod is configured to include a piston portion that can slide within the cylinder, and a rod portion that extends from the piston portion and protrudes outside the cylinder, and moves the hood panel of the vehicle, which serves as a receiving material for receiving a pedestrian, upward to a pedestrian receiving position. In this actuator, when it is activated, the piston rod moves the piston portion forward within the cylinder to the forward movement completion position, while the tip of the rod portion abuts against the hood panel, and lifts the hood panel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-133535 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional actuators, if the hood panel's portion where the tip of the rod portion of the piston rod abuts is subjected to a large upward bouncing force from the hood panel, in other words, the pushing force of the piston rod moving forward, it can be damaged. This makes it necessary to make adjustments such as providing a reinforcing material at the portion where the tip of the rod portion abuts, which results in an increase in the weight of the hood panel and makes it difficult to deal with in a simple manner.

[0005] The present invention is devised to solve the above-mentioned problems, and has an object to provide an actuator that allows easy adjustment of the pressing force of a piston rod during operation. [Means for solving the problem]

[0006] The actuator according to the present invention is an actuator configured such that a piston portion of a piston rod in a cylinder moves toward a ceiling portion of the cylinder by working gas consisting of combustion gas generated upon activation of a gas generator arranged at the bottom of the cylinder, and a rod portion of the piston rod extending so as to penetrate the ceiling portion is moved forward to move a pressed portion against which a tip end of the rod portion abuts, the cylinder includes a throttle portion between the piston portion and the gas generator before activation, the throttle portion having a gas passage hole having an opening diameter smaller than an opening diameter of an inner circumferential surface of the piston portion that slides, through which the working gas passes, The piston portion is A main body portion that slides on the inner circumferential surface of the cylinder during operation; a fitting portion that protrudes from the main body portion toward a bottom side of the cylinder and is fitted and inserted into the gas insertion hole so as to be removable from the gas insertion hole of the throttle portion when the working gas is discharged from the gas generator; The present invention is characterized in that it is configured to include the following.

[0007] In the actuator according to the present invention, when the gas generator discharges the working gas during operation, the working gas presses the fitting-insertion portion in an attempt to pass through the gas insertion hole of the throttle portion, causing the fitting-insertion portion to leave the gas insertion hole, and the working gas that has passed through the gas insertion hole presses the piston portion including the fitting-insertion portion and the main body portion. At that time, the fitting-insertion portion pressed by the working gas at the beginning of operation is pressed by the pressure of the working gas according to the opening area of ​​the gas insertion hole into which it is fitted, and after the fitting-insertion portion leaves the gas insertion hole, the piston portion including the fitting-insertion portion and the main body portion is pressed by the pressure of the working gas according to the opening area on the inner circumferential surface side of the cylinder in which the main body portion slides, causing the piston rod to move forward. That is, the pressing force (pressing load) of the piston rod at the beginning of the operation is a value obtained by multiplying the opening area of ​​the gas insertion hole by the pressure of the working gas, and is smaller than the value obtained by multiplying the opening area of ​​the inner peripheral surface of the cylinder on which the entire piston part slides by the pressure of the working gas. Therefore, since the pressing load of the piston rod at the beginning of the operation is small, the pressing load when the piston rod abuts the tip of the rod part against the pressed part after the fitting part leaves the gas insertion hole can be suppressed to be smaller than when the pressure of the working gas acts on the opening area of ​​the inner peripheral surface of the cylinder on which the entire piston part slides from the beginning of the operation. Also, even if the length of the gas insertion hole is long, it is possible to maintain the state of the small pressing load at the beginning of the operation until the fitting part leaves the gas insertion hole significantly, compared to the case where the gas insertion hole is short, and the pressing load when the piston rod abuts the tip of the rod part against the pressed part thereafter can also be suppressed to be small.

[0008] Therefore, in the actuator according to the present invention, the pressing force of the piston rod during operation can be easily adjusted by simply adjusting the opening area and length of the gas insertion hole into which the insertion fit portion is inserted.

[0009] In the actuator according to the present invention, the gas insertion hole of the throttle portion has a cylindrical inner circumferential surface along an axial direction of the gas insertion hole, The fitting portion may be configured to include a sliding portion that is slidable on an inner circumferential surface of the gas insertion hole.

[0010] In such a configuration, when the actuator is initially activated, the sliding portion of the insertion portion slides a certain distance along the inner surface of the gas insertion hole, and the low pressing force (pressing load) of the piston rod at the beginning of activation can be maintained for a long period of time corresponding to the sliding distance, and the pressing force when the piston rod subsequently abuts the tip portion of the rod portion against the pressed portion can also be kept small.

[0011] In addition, in the actuator of the present invention, the insertion portion may be configured to include an outer peripheral edge portion that abuts against the entire circumference of the edge of the ceiling side of the cylinder at the gas insertion hole, and an insertion portion whose outer diameter dimension gradually narrows from the outer peripheral edge portion and is inserted into the gas insertion hole.

[0012] In this configuration, when the fitting-insertion portion is released from the gas insertion hole at the beginning of operation of the actuator, the outer peripheral edge portion of the fitting-insertion portion can quickly separate from the periphery of the gas insertion hole, and the working gas that has passed through the gas insertion hole can flow to the bottom side of the main body of the piston portion of the piston rod. In other words, the state of a low pressing load on the piston rod due to the pressure of the working gas acting on the fitting-insertion portion at the beginning of operation of the actuator lasts for a short period of time, and the suppression of the pressing force when the tip end of the rod portion of the piston rod is brought into contact with the pressed portion can be adjusted to be smaller.

[0013] Furthermore, the actuator according to the present invention may be used in a hood lifting device in which the tip portion of the rod portion abuts against a rear side portion of a vehicle hood panel as a pressed portion, thereby lifting up the hood panel. [Brief description of the drawings]

[0014] [Figure 1] 1 is an explanatory diagram showing a state before operation of a hood lift-up device in which an actuator according to an embodiment of the present invention is used; [Diagram 2] 1 is an explanatory diagram showing a state in which a hood lift-up device using an actuator according to an embodiment is in operation; FIG. [Diagram 3] 5A to 5C are schematic cross-sectional views of the actuator of the embodiment before and after actuation. [Figure 4] FIG. 4 is a schematic enlarged cross-sectional view illustrating an initial stage of operation of the actuator of the embodiment. [Diagram 5] FIG. 11 is a schematic enlarged cross-sectional view illustrating an early stage of operation of a modified example of the actuator of the embodiment. [Figure 6] FIG. 11 is a schematic enlarged cross-sectional view illustrating an initial stage of operation of another modified example of the actuator of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] An embodiment of the present invention will now be described with reference to the drawings. As shown in FIGS. 1 to 3, an actuator 20 of the embodiment is used in a hood lift-up device U as an automobile safety device, and is disposed near the front side of a hinge mechanism 9 below a rear end 7c of a hood panel 7 of a vehicle V.

[0016] In this embodiment, a sensor capable of detecting or predicting a collision with a pedestrian is provided on the front bumper (not shown) of the vehicle V, and when a control circuit (not shown) which receives a signal from the sensor detects a collision between the vehicle V and a pedestrian based on the signal from the sensor, it ignites a gunpowder (not shown) in a gas generator 38 (described later) of the actuator 20, and uses the combustion gas as operating gas G to extend the actuator 20 and activate the pop-up device U.

[0017] As shown in FIG. 1, the hood panel 7 covers the upper part of the engine room ER of the vehicle V, and is connected to the vehicle body 1 of the vehicle V by a hinge mechanism 9 arranged near the rear end 7c on both left and right edges of the vehicle V so that the hood panel can be opened and closed in a front-opening manner. The hood panel 7 is made of sheet metal made of aluminum alloy or the like, and is composed of an outer panel 7a on the upper surface side and an inner panel 7b located on the lower surface side and having improved strength than the outer panel 7a. The hood panel 7 is configured to be plastically deformable so as to absorb the kinetic energy of a pedestrian when the hood panel 7 receives the pedestrian. In the embodiment, when the vehicle V collides with the pedestrian, the actuator 20 is actuated, and as shown in FIG. 2, a deformation space D can be formed between the rear end 7c of the raised hood panel 7 and the engine room ER, so that the amount of plastic deformation during bending plastic deformation can be increased, and the hood panel 7 can absorb a large amount of the pedestrian's kinetic energy.

[0018] The hinge mechanism 9 is configured to include a hinge base 10 fixed to a mounting flange 2a on the body 1 side below the rear end 7c of the hood panel 7, and a hinge arm 12 pivotally supported by the hinge base 10 using a support shaft 11 and connected to the underside of the rear end 7c of the hood panel 7. The mounting flange 2a is connected to the hood ridge reinforcement 2 on the body 1 side. The hinge mechanism 9 is configured to open around the support shaft 11 on the base end 12a side of the hinge arm 12 as the rotation center when the hood panel 7 is opened during normal use (see the two-dot chain line in FIG. 1).

[0019] The hinge arm 12 has a mounting portion 12d on the tip side extending forward from the base end 12a, which is fixed to the inner panel 7b. The mounting portion 12d is provided with a contact portion 12e that receives a tip portion 53 (described later) on its underside when the actuator 20 is actuated. Furthermore, the hinge arm 12 has a notch 12f provided near the mounting portion 12d to facilitate plastic deformation, and when the rising tip portion 53 of the actuator 20 actuates and contacts the contact portion 12e, the plastic deformation portion 12g near the notch 12f is plastically deformed, and the rear end 7c of the hood panel 7 is raised together with the contact portion 12e and the mounting portion 12d so as to provide a deformation space D.

[0020] 1 to 4, the actuator 20 is of a piston cylinder type and includes a cylinder 22 having a gas generator 38 provided at its bottom 36, and a piston rod 40. The actuator 20 is held by a mounting bracket 18 fixed to the body 1 side of the vehicle V, and is disposed below the rear end 7c of the hood panel 7, more specifically, below the abutment portion 12e.

[0021] The gas generator 38 uses a squib or a micro gas generator that ignites a predetermined explosive (not shown) when activated, and generates a combustion gas used as the working gas G by burning the explosive itself or by burning a gas generating agent ignited by the explosive, and a connector 38b for connecting a lead wire (not shown) for inputting an ignition electric signal from a predetermined control circuit is provided on the base side exposed from the bottom 36 away from the tip 38a that discharges the working gas G. When an ignition electric signal is input from a control circuit (not shown), the gas generator 38 ignites and burns the built-in explosive, and further burns the gas generating agent as appropriate, generating a combustion gas, which is discharged from the tip 38a as the working gas G and supplied to the piston portion 41 side.

[0022] The cylinder 22 is configured such that a gas generator 38 is disposed on the bottom 36 side, a ceiling 23 on the tip (upper end) side away from the bottom 36 is provided with an insertion hole 24 through which a rod portion 52 of a piston rod 40 described later is inserted, and a peripheral wall portion 26 having an inner peripheral surface 26a through which a piston portion 41 of the piston rod 40 slides is provided between the bottom 36 and the ceiling 23. The cylinder 22 is formed by pressing a metal pipe such as a steel pipe, and a block material 25 made of a steel material or the like having an insertion hole 24 formed on the ceiling 23 side is fixed by crimping, and the gas generator 38 is disposed on the bottom 36 side and the edge 36a is crimped to fix the gas generator 38.

[0023] The cylinder 22 is formed with a tapered throttle portion 28 that is narrowed so as to narrow the inner diameter in the vicinity of directly above the gas generator 38 between the main body portion 42 of the piston portion 41 and the gas generator 38 before actuation. The throttle portion 28 is formed with a gas insertion hole 29 having an opening diameter d1 smaller than the opening diameter d2 of the inner circumferential surface 26a of the peripheral wall portion 26. The inner circumferential surface 26a of the peripheral wall portion 26 and the inner circumferential surface 29a of the gas insertion hole 29 are configured as circular openings.

[0024] The piston rod 40 is made of a steel material or the like and is configured to include a piston portion 41 disposed in the cylinder 22, and a rod portion 52 extending from the piston portion 41 and protruding through an insertion hole 24 in a ceiling portion 23 of the cylinder 22. A tip portion 53 of the rod portion 52 is formed by screwing a block material 54 made of steel or the like to a tip portion 52a side of the rod portion 52.

[0025] The piston portion 41 is configured to include a cylindrical main body portion 42 that slides on the inner surface 26a of the peripheral wall portion 26 of the cylinder 22 during operation, and an insertion portion 46 that protrudes from the main body portion 42 toward the bottom portion 36 of the cylinder 22 and is fitted into the gas insertion hole 29 of the throttling portion 28 so as to be removable from the gas insertion hole 29 when the operating gas G of the gas generator 38 is discharged.

[0026] In this embodiment, the gas passage hole 29 of the constriction portion 28 is configured with a cylindrical inner surface 29a that extends along the axial direction XD of the gas passage hole 29, and the fitting portion 46 is configured with a cylindrical sliding portion 47 that is capable of sliding on the inner surface 29a of the gas passage hole 29.

[0027] The piston portion 41 has grooves 43, 48 formed on outer circumferential surfaces 42a, 46a of the main body portion 42 and the sliding portion 47 of the insertion portion 46 to improve gas sealing properties, and seal members 44, 49 made of rubber or the like are disposed therein.

[0028] In the actuator 20 of this embodiment, by connecting a lead wire from a control circuit (not shown) to the connector 38b of the gas generator 38 and attaching and fixing the cylinder 22 to a portion of the vehicle V below the rear end 7c of the hood panel 7 using the mounting bracket 18, the pop-up device U can be mounted on the vehicle V to which the hinge mechanism 9 has already been attached.

[0029] After the flip-up device U is mounted on the vehicle V, when the actuator 20 is activated, the gas generator 38 generates the working gas G, and the pushing force of the working gas G causes the rod portion 52 of the piston rod 40 of the actuator 20 to protrude from the cylinder 22 as shown in Figures 1 and 2, and the tip portion 53 at the upper end of the rod portion 52 abuts against the abutment portion 12e, pushing up the abutment portion 12e together with the rear end 7c of the hood panel 7. As a result, the rear end 7c side of the hood panel 7 is pushed up, ensuring a wide deformation space D, and the increased amount of plastic deformation allows the pedestrian to be received with the impact mitigated.

[0030] In the actuator 20 of the embodiment, when the gas generator 38 discharges the working gas G during operation, as shown in Figures 4A and 4B, the working gas G attempts to pass through the gas insertion hole 29 of the throttling portion 28, pressing against the fitting portion 46 and causing the fitting portion 46 to separate from the gas insertion hole 29. Then, the working gas G having passed through the gas insertion hole 29 presses against the piston portion 41 including the fitting portion 46 and the main body portion 42. At that time, the insertion portion 46, which is pressed by the working gas G at the beginning of operation, is pressed by the pressure of the working gas G according to the opening area S1 of the gas insertion hole 29 into which it is inserted, and after the insertion portion 46 leaves the gas insertion hole 29, the piston portion 41 consisting of the insertion portion 46 and the main body portion 42 is pressed by the pressure of the working gas G according to the opening area S2 on the inner surface 26a side of the cylinder 22 against which the main body portion 42 slides, and the piston rod 40 moves forward.

[0031] That is, the pressing force (pressing load) F1 of the piston rod 40 at the beginning of operation is the value (F1=S1×P) obtained by multiplying the opening area S1 of the gas insertion hole 29 by the pressure P of the working gas G, and is smaller than the value (F2=S2×P) obtained by multiplying the opening area S2 of the inner circumferential surface 26a of the cylinder 22 on which the entire piston portion 41 slides by the pressure of the working gas G. In other words, S2>S1, The initial pressure load F1 = S1 × P is: F2 = S2 × P is smaller than the value (F1 <F2)。

[0032] Therefore, since the pressing load F1 of the piston rod 40 at the beginning of the operation is small, the pressing load FX (see FIG. 2) when the piston rod 40 brings the tip 53 of the rod portion 52 into contact with the contact portion 12e as the pressed portion after the fitting portion 46 leaves the gas insertion hole 29 can be suppressed to be smaller than the case where the pressure P of the working gas G acts on the opening area S2 of the inner circumferential surface 26a of the cylinder 22 on which the entire piston portion 41 slides from the beginning of the operation. Even if the length dimension L (see FIG. 4) of the gas insertion hole 29 is increased, the state of the small pressing load F1 at the beginning of the operation can be maintained for a long time until the fitting portion 46 leaves the gas insertion hole 29, compared to the case where the gas insertion hole 29 is made short, and the pressing load FX when the piston rod 40 brings the tip 53 of the rod portion 52 into contact with the contact portion 12e as the pressed portion can also be suppressed to be small.

[0033] Therefore, in the actuator 20 of the embodiment, the pressing force FX of the piston rod 40 during operation can be easily adjusted simply by adjusting the opening area S1 and length dimension L of the gas insertion hole 29 into which the insertion portion 46 is inserted.

[0034] In the actuator 20 of the embodiment, the gas passage hole 29 of the restricting portion 28 has a cylindrical inner surface 29a that extends along the axial direction XD of the gas passage hole 29, and the fitting portion 46 is configured to have a sliding portion 47 that is slidable on the inner surface 29a of the gas passage hole 29.

[0035] Therefore, in the embodiment, when the actuator 20 is initially operated, the sliding portion 47 of the insertion portion 46 slides on the inner surface 29a of the gas insertion hole 29 a certain distance, and the pressing force (pressing load) F1 of the piston rod 40 at the beginning of operation can be maintained for a long time for that sliding distance SL (see Figure 4), and the pressing force FX when the piston rod 40 subsequently abuts the tip portion 53 of the rod portion 52 against the abutment portion 12e as the pressed portion can also be kept small.

[0036] In addition, the insert portion may be a mushroom-shaped puppet valve-type insert portion 66 as in the actuator 20A shown in FIG. 5, in addition to the cylindrical shape.

[0037] In this actuator 20A, the insertion portion 66 of the piston rod 40A is conically shaped and includes an outer peripheral edge portion 67 that abuts against the entire circumference of the periphery 31 on the ceiling side of the cylinder 22A at the gas insertion hole 29A provided in the throttle portion 28A, and an insertion portion 68 whose outer diameter dimension gradually narrows from the outer peripheral edge portion 67 and is inserted into the gas insertion hole 29A.

[0038] In the actuator 20A having such a configuration, when the fitting-insertion portion 66 is released from the gas through hole 29A at the beginning of operation, the outer peripheral edge portion 67 of the fitting-insertion portion 66 can quickly leave the periphery 31 of the gas through hole 29A, and the working gas G that has passed through the gas through hole 29A can flow to the bottom surface 42b side of the main body portion 42 of the piston portion 41 in the piston rod 40A. That is, the state of the low pressing load F1 (opening area S1 of the gas through hole 29A × pressure P of the working gas G) of the piston rod 40A due to the pressure P of the working gas G acting on the fitting-insertion portion 66 at the beginning of operation of the actuator 20A becomes short, and the suppression of the pressing force FX when the tip portion 53 of the rod portion 52 in the piston rod 40A is brought into contact with the contact portion 12e as the pressed portion can be adjusted to be smaller (see FIG. 2).

[0039] Although the configuration of this actuator 20A is different from that of actuator 20 in the vicinity of the insertion portion 66 and the gas insertion hole 29A, other portions such as the ceiling portion 23 side of the cylinder 22A and the main body portion 42 of the piston portion 41 of the piston rod 40A have the same configuration as actuator 20.

[0040] Moreover, the fitting portion may be a spherical fitting portion 66B, as in the actuator 20B shown in FIG.

[0041] In this actuator 20B, the fitting portion 66B of the piston rod 40B is spherical and includes an outer peripheral edge portion 67B that abuts against the entire circumference of the peripheral edge 31B on the ceiling side of the cylinder 22B at the gas insertion hole 29B provided in the throttle portion 28B, and an insertion portion 68B that is inserted into the gas insertion hole 29B with an outer diameter gradually narrowed from the outer peripheral edge portion 67B. A chamfered abutment seat 33 against which the outer peripheral edge portion 67B abuts is formed at the portion of the peripheral edge 31B that abuts against the outer peripheral edge portion 67B.

[0042] In the actuator 20B having such a configuration, when the fitting-insertion portion 66B is released from the gas insertion hole 29B at the beginning of operation, the outer peripheral edge portion 67B of the fitting-insertion portion 66B can quickly separate from the periphery 31B of the gas insertion hole 29B, and the working gas G that has passed through the gas insertion hole 29B can flow to the bottom surface 42b side of the main body portion 42 of the piston portion 41 in the piston rod 40B. That is, the state of the low pressing load F1 (opening area S1 of the gas insertion hole 29B × pressure P of the working gas G) of the piston rod 40B due to the pressure P of the working gas G acting on the fitting-insertion portion 66B at the beginning of operation of the actuator 20B becomes short, and the suppression of the pressing force FX when the tip portion 53 of the rod portion 52 in the piston rod 40B is brought into contact with the contact portion 12e as the pressed portion can be adjusted to be smaller (see FIG. 2).

[0043] Incidentally, although the configuration of the insertion portion 66B and the gas insertion hole 29B in the vicinity of this actuator 20B is different from that of the actuator 20, the ceiling portion 23 side of the other cylinders 22B and the main body portion 42 of the piston portion 41 of the piston rod 40B, etc., are configured in the same manner as the actuator 20.

[0044] In addition, the actuators 20, 20A, and 20B in the embodiments are shown as being used in a lift-up device U that lifts up the hood panel 7, but the actuators can be used in various automobile safety devices without being limited to the embodiments as long as the gas generator is activated to move the piston rod forward at a predetermined time. [Explanation of symbols]

[0045] 7...hood panel, 20, 20A, 20B...actuator, 22, 22A, 22B...cylinder, 23...ceiling portion, 26...peripheral wall portion, 26a...(sliding portion) inner peripheral surface, 28, 28A, 28B...throttling portion, 29, 29A, 29B...gas insertion hole, 29a...inner peripheral surface, 31, 31B...(ceiling side) periphery, 36...bottom portion, 38...gas generator, 40, 40A, 40B...piston rod, 41...piston portion, 42...main body portion, 46...insertion portion, 47...sliding portion, 52...rod portion, 53...tip portion, 66, 66B...insertion portion, 67, 67B...outer peripheral edge portion, 68, 68B...insertion portion, d0...(cylinder) opening diameter, d1...(gas hole) opening diameter, G...(operating gas), U...(automobile safety device) hood lift-up device.

Claims

1. An actuator configured such that a piston portion of a piston rod in the cylinder moves toward a ceiling portion of the cylinder by working gas consisting of combustion gas generated upon activation of a gas generator disposed at a bottom of the cylinder, thereby moving a rod portion of the piston rod extending so as to penetrate the ceiling portion forward and moving a pressed portion against which a tip end of the rod portion abuts, the cylinder includes a throttle portion between the piston portion and the gas generator before activation, the throttle portion having a gas passage hole having an opening diameter smaller than an opening diameter of an inner circumferential surface of the piston portion that slides, through which the working gas passes, The piston portion is A main body portion that slides on the inner circumferential surface of the cylinder during operation; a fitting portion that protrudes from the main body portion toward a bottom side of the cylinder and is fitted and inserted into the gas insertion hole so as to be removable from the gas insertion hole of the throttle portion when the working gas is discharged from the gas generator; The present invention is configured with The narrowing portion is a fitting portion into which the fitting portion of the piston portion before actuation fits; a tapered portion disposed on the gas generator side with respect to the fitting portion, the tapered portion having an opening diameter gradually narrowing from the bottom side toward the ceiling side; having The actuator, wherein the gas generator is disposed in contact with the tapered portion.

2. the gas insertion hole of the throttle portion has a cylindrical inner circumferential surface along an axial direction of the gas insertion hole, 2. The actuator according to claim 1, wherein the fitting portion is provided with a sliding portion that is slidable against an inner circumferential surface of the gas insertion hole.

3. 3. The actuator according to claim 1 or 2, characterized in that the tip of the rod portion is used in a hood lifting device configured to abut against a rear side portion of a hood panel of a vehicle as a pressed portion, thereby lifting up the hood panel.

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