JP7577993B2 - Hood lifting device actuator - Google Patents

Description

The present invention relates to an actuator for a hood lifting device that pushes up the hood (bonnet hood) of an automobile when a collision with a pedestrian or the like is detected or predicted.

One actuator used in an automobile hood lifting device is equipped with a gas generator, a cylinder, and a piston rod. When the gas generator is activated, the piston rod protrudes from the cylinder, lifting the hood.

To prevent the protruding piston rod from retracting, a tapered surface is provided on the circumferential surface of the piston portion, and a ball is placed between the tapered surface and the inner circumferential surface of the cylinder. When the piston rod attempts to retract, the ball becomes caught between the tapered surface and the inner circumferential surface of the cylinder. Then, a component of force from the tapered surface of the piston rod attempting to retract presses the ball against the inner circumferential surface of the cylinder, causing the ball to bite into the inner circumferential surface of the cylinder. This prevents the piston rod from retracting.

This tapered surface is circular in cross section perpendicular to the axis of the piston rod. Multiple balls are arranged around this tapered surface, which has a circular cross section.

JP 2011-162136 A

The objective of the present invention is to provide an actuator for a hood lifting device that has a piston rod configured to regulate the depth to which balls or the like for preventing the piston rod from retracting penetrate into the inner surface of the cylinder.

The actuator for a hood lifting device of the present invention is an actuator for a hood lifting device that uses gas pressure to move a piston rod disposed in a cylinder to lift the hood of a vehicle, and is characterized in that an intermediary body for preventing the piston rod from retracting is disposed between a tapered surface provided on the base end side of the piston rod and the inner peripheral surface of the cylinder, and the piston rod is provided with a means for regulating the reaction force that the piston rod exerts on the hood after the hood is lifted.

In one aspect of the present invention, the intermediate body is a ball or a ring.

In one aspect of the present invention, the tapered surface is shaped to expand in the direction in which the piston rod protrudes, and the means for regulating the reaction force is a regulating surface that extends in a substantially radial direction from the tip of the tapered surface in the direction in which the piston rod protrudes.

In one aspect of the present invention, the regulating surface is a plane perpendicular to the piston rod axis.

In one aspect of the present invention, the regulating surface is at least partially an inclined surface that is inclined with respect to a direction perpendicular to the piston rod axis. This inclined surface may be an inclined surface that is in the direction of piston rod protrusion as it moves radially outward, or an inclined surface that is in the opposite direction to the direction of piston rod protrusion as it moves radially outward.

In one aspect of the present invention, the regulating surface is convex in the direction opposite to the piston rod protruding direction. In another aspect of the present invention, the regulating surface is concave in the piston rod protruding direction.

In one aspect of the present invention, a coating is applied to the tapered surface or the regulating surface of the piston rod.

In one aspect of the present invention, a cylinder deformation suppression member is attached to the outer circumferential surface of the cylinder.

In one aspect of the present invention, when the piston rod protrudes, the intermediate body passes through the inner region of the cylinder deformation suppression member via the cylinder.

In one aspect of the present invention, the upper surface side of the cylinder deformation suppression member prevents the intermediate body from retracting.

In one aspect of the present invention, the cylinder deformation suppression member is made of metal.

In one aspect of the present invention, the cylinder deformation suppression member is arranged to surround the outer circumferential surface of the cylinder.

In one aspect of the present invention, a plurality of the intermediate bodies are provided, and a plurality of the cylinder deformation suppression members are attached at intervals in the circumferential direction of the cylinder.

In one aspect of the present invention, the cylinder deformation suppression member is integrated with a bracket for mounting the hood lifting device actuator to the vehicle body.

In the actuator for a hood lifting device of the present invention, when the gas generator is activated, the piston rod protrudes and pushes up the hood. If the piston rod then attempts to retract due to the pressing force from the hood, the intervening body interposed between the piston rod and the inner circumferential surface of the cylinder prevents the piston rod from retracting, and a reaction force is applied to the hood attempting to descend. In the present invention, a restriction means for restricting this reaction force is provided on the piston rod, which simplifies the structure of the cylinder.

FIG. 2 is a longitudinal cross-sectional view of the actuator according to the embodiment in a pre-operation state. FIG. 2 is an enlarged view of part II in FIG. 2 is a cross-sectional view of the actuator of FIG. 1 after actuation. FIG. 11 is a cross-sectional view of an actuator according to another embodiment. FIG. 11 is a cross-sectional view of an actuator according to another embodiment. FIG. 11 is a cross-sectional view of an actuator according to another embodiment. FIG. 11 is a cross-sectional view of an actuator according to another embodiment. FIG. 11 is a cross-sectional view of an actuator according to another embodiment. FIG. 11 is a cross-sectional view of an actuator according to another embodiment. FIG. 10 is a cross-sectional view of the actuator of FIG. 9 after actuation. FIG. FIG.

Below, an embodiment of the present invention will be described with reference to the drawings.

Figure 1 shows an actuator 1 for a hood lifting device according to an embodiment. This hood lifting device is designed to lift the rear of the hood when a vehicle collides with a pedestrian, thereby mitigating the impact on the pedestrian.

In the following explanation, the end of the piston rod in the protruding direction is referred to as the upper end or tip, and the end opposite to the protruding direction is referred to as the lower end or rear end.

This actuator 1 is a linear actuator having a cylinder 2 and a piston rod 3. A gas generator 4 is provided at the rear end of the cylinder 2. The gas generator 4 is connected to an ECU (electronic control unit) (not shown) and operates based on commands from the ECU to generate high-pressure gas. This high-pressure gas pushes up the piston rod 3, causing it to protrude from the cylinder 2.

A flange-shaped end member 5 with a hole in the center is fixed to the tip of the cylinder 2. The inner peripheral edge of the end member 5 protrudes toward the center beyond the inner peripheral edge of the cylinder 2.

The tip of the piston rod 3 protrudes upward through the central hole of the end member 5. A groove is provided around the inner circumferential surface of the end member 5, and a ring-shaped stopper ring 6 engages with this groove.

Although not shown in the figure, claw pieces protrude outward (radially) from the outer periphery of the stopper ring 6, and these claw pieces engage with grooves on the inner periphery of the end member 5. Multiple claw pieces are provided at intervals around the circumference of the stopper ring 6.

The stopper ring 6 prevents the piston rod 3 from protruding upward during normal operation (when the gas generator is not in operation). A cover cap 7 is attached to the tip of the piston rod 3.

As shown in FIG. 2, the rear end of the piston rod 3 is a piston portion 8. A groove 9 is provided around the outer circumferential surface of the piston portion 8. An O-ring 10 is disposed in the groove 9 and is in airtight and slidable contact with the inner circumferential surface of the cylinder 2.

The area above the piston portion 8 is the small diameter portion 11, and the area above the small diameter portion 11 is the large diameter portion 12. The diameter of the large diameter portion 12 is slightly smaller than the inner diameter of the cylinder 2.

The small diameter portion 11 has a generally inverted truncated cone shape. The side surface of the small diameter portion 11 has a tapered surface 13 in which the distance between the small diameter portion 11 and the inner surface of the cylinder 2 decreases the further upward. The distance between the lower end of the small diameter portion 11 and the inner surface of the cylinder 2 is slightly larger than the diameter of the ball 15. In addition, the distance between the upper end of the small diameter portion 11 and the inner surface of the cylinder 2 is smaller than the diameter of the ball 15.

The lower surface of the large diameter portion 12, i.e., the step surface at the boundary between the tapered surface 13 and the large diameter portion 12, is a restricting surface 14 consisting of a plane extending in the radial direction. In this embodiment, the restricting surface 14 consists of a plane extending perpendicular to the axis of the piston rod 3.

A ball 15 is disposed between the tapered surface 13 and the inner circumferential surface of the cylinder 2. Before the actuator 1 is activated, the ball 15 abuts against the step surface (the upper surface of the small diameter portion 11) on the small diameter portion 11 side of the piston rod 3. In this state, the ball 15 is in slidable contact with the inner circumferential surface of the cylinder 2, or there is a small gap between the two.

The ball 15 and the piston rod 3 are made of a material that is more rigid than the cylinder 2.

Next, the operation of this actuator 1 will be explained. When the detection system detects or predicts a collision between a vehicle and a pedestrian, the gas generator 4 operates based on a command from the ECU and generates high-pressure gas. The high-pressure gas is supplied into the cylinder 2, causing the piston rod 3 to move upward.

The piston rod 3 deforms the tab (not shown) of the stopper ring 6, protruding upward and pushing up the rear of the bonnet hood. The piston rod 3 moves upward until the large diameter portion 12 hits the end member 5.

While the piston rod 3 moves upward, the ball 15 abuts against the upper surface of the small diameter portion 11 and does not restrict the movement of the piston rod 3.

When a load is applied to the raised bonnet hood by a pedestrian or the like, causing the rear of the bonnet hood and the piston rod 3 to move downward, the ball 15 moves upward relative to the piston rod 3 and becomes wedged between the inner circumferential surface of the cylinder 2 and the tapered surface 13. Due to the downward load F applied to the piston rod 3, the ball 15 receives a radial component force from the tapered surface 13, and is pressed against the inner circumferential surface of the cylinder 2, wedging it into the inner circumferential surface of the cylinder 2.

The ball 15 begins to bite into the inner circumferential surface of the cylinder 2 before the ball 15 comes into contact with the regulating surface 14. The piston rod 3 moves downward while the ball 15 deforms the inner circumferential surface of the cylinder 2. The ball 15 that has bitten into the inner circumferential surface of the cylinder 2 moves upward relative to the piston rod 3 and comes into contact with the regulating surface 14 as shown in Figure 3, and then moves downward together with the piston rod 3.

After that, when the load F from above becomes smaller than the reaction force from the piston rod 3, the downward movement of the piston rod 3 stops.

In this embodiment, after the ball 15 abuts against the restricting surface 14, the ball 15 does not move any further upward relative to the piston rod 3, so the reaction force that the piston rod 3 exerts on the bonnet hood 3 does not increase any further. In other words, by providing the restricting surface 14, the reaction force that the piston rod 3 exerts on the bonnet hood 3 is restricted to a predetermined value or less.

In this embodiment, the regulating surface 14 is provided on the piston rod 3, and the configuration of the cylinder 2 is simple.

In the above embodiment, the regulating surface 14 is a plane extending perpendicular to the axis of the piston rod, but the present invention is not limited to this.

For example, as shown in FIG. 4, the control surface 14A may be a curved surface that is convexly curved downward, or as shown in FIG. 5, the control surface 14B may be a curved surface that is concavely curved. Note that the control surfaces 14A and 14B may have a V-shaped cross section instead of a curved surface.

As shown in FIG. 6, the regulating surface 14C may be a surface that slopes downward toward the outer periphery in the radial direction, and as shown in FIG. 7, the regulating surface 14D may be a surface that slopes upward toward the outer periphery in the radial direction. Note that while the entire regulating surface 14C, 14D in FIGS. 6 and 7 is an inclined surface, only a portion of the regulating surface may be an inclined surface.

In the present invention, an intermediate body other than a ball may be used. For example, as shown in FIG. 8, a ring 16 surrounding the small diameter portion 11 may be used as the intermediate body. The ring 16 may be a C-ring with a cut in the middle in the circumferential direction. A roller may also be used as the intermediate body.

The rest of the configuration of the actuator in Figures 4 to 8 is the same as that of the actuator in Figures 1 to 3, and the same reference numerals indicate the same parts.

The above embodiments are merely examples of the present invention, and the present invention may take other forms.

For example, in the present invention, at least a portion of the piston rod, such as the tapered surface or the restricting surface, may be coated with a coating to adjust the friction coefficient.

In the above embodiment, when the piston rod 3 moves downward after moving upward, the ball 15 may move downward together with the piston rod 3 while deforming the side wall of the cylinder 2. For this reason, as shown in Figures 9 and 10, a deformation suppression member 20 that suppresses deformation of the cylinder side wall may be attached to the outer circumferential surface of the cylinder 2.

Even if the ball 15 moves downward together with the piston rod 3 while deforming the side wall of the cylinder 2, the deformation of the cylinder side wall is suppressed at the position of the deformation suppression member 20, and the downward movement of the ball 15 and the piston rod 3 is stopped, as shown in FIG. 11. For example, the downward movement of the ball 15 and the piston rod 3 is stopped (prevented) on the upper surface side of the deformation suppression member 20.

In this way, by providing the deformation suppression member 20, the downward movement of the piston rod 3 can be stopped at a desired position. Furthermore, the mounting position of the deformation suppression member 20 can be changed according to the position where the downward movement of the piston rod 3 is stopped, and a cylinder with a constant wall thickness and outer diameter can be used for the cylinder 2. There is no need to increase the number of types of cylinders, which reduces costs.

The deformation suppression member 20 is made of a metal, and for example, SS400 can be used. The thickness of the deformation suppression member 20 is not particularly limited, and may be approximately the same as the thickness of the cylinder, or may be greater than or less than the thickness of the cylinder. The method of attaching the deformation suppression member 20 to the outer peripheral surface of the cylinder is not particularly limited, and may be, for example, attached by brazing, adhesive, welding, etc.

Figure 10 shows a configuration in which the deformation suppression members 20 surround the outer peripheral surface of the cylinder, but they may be partially provided to match the position of the balls 15. For example, the same number of deformation suppression members 20 as the number of balls 15 may be provided at intervals around the circumference of the cylinder 2. When the balls 15 move upward together with the piston rod 3, they pass through the area inside the deformation suppression members 20 (on the piston rod axis side) via the cylinder 2.

The deformation suppression member 20 shown in FIG. 10 has a cylindrical configuration with curved side walls, but as shown in FIG. 12, the deformation suppression member 20A may have side walls made of multiple flat surfaces.

As shown in FIG. 13, the deformation suppression member 20B may be integrated with a bracket 30 for mounting the hood lifting device actuator 1 to a vehicle body member.

REFERENCE SIGNS LIST 1 actuator 2 cylinder 3 piston rod 4 gas generator 8 piston portion 11 small diameter portion 12 large diameter portion 13 tapered surface 14, 14A to 14D restriction surface 15 ball 16 ring 20, 20A, 20B deformation suppressing member

Claims (7)

An actuator for a hood lifting device that lifts a hood of a vehicle by moving a piston rod disposed in a cylinder by gas pressure,
an intermediary body for preventing the piston rod from moving backward is disposed between a tapered surface provided on the base end side of the piston rod and an inner peripheral surface of the cylinder;
The tapered surface has a shape that expands in diameter toward a protruding direction of the piston rod,
a flat surface is provided extending perpendicularly to an axis of the piston rod from a tip end side of the tapered surface in a protruding direction of the piston rod,
the intermediate body abuts against the flat surface when the piston rod retracts after the hood is lifted. An actuator for a hood lifting device that lifts a hood of a vehicle by moving a piston rod disposed in a cylinder by gas pressure,
an intermediary body for preventing the piston rod from moving backward is disposed between a tapered surface provided on the base end side of the piston rod and an inner peripheral surface of the cylinder;
The tapered surface has a shape that expands in diameter toward a protruding direction of the piston rod,
An inclined surface is provided extending radially from a tip end side of the tapered surface in a protruding direction of the piston rod,
The actuator for a hood lifting device, wherein the inclined surface becomes in a direction opposite to a protruding direction of the piston rod toward an outer periphery in a radial direction. An actuator for a hood lifting device that lifts a hood of a vehicle by moving a piston rod disposed in a cylinder by gas pressure,
an intermediary body for preventing the piston rod from moving backward is disposed between a tapered surface provided on the base end side of the piston rod and an inner peripheral surface of the cylinder;
The tapered surface has a shape that expands in diameter toward a protruding direction of the piston rod,
An inclined surface is provided extending radially from a tip end side of the tapered surface in a protruding direction of the piston rod,
The actuator for a hood lifting device, wherein the inclined surface is curved convexly in a direction opposite to a direction in which the piston rod projects. The actuator for a hood lifting device of claim 1, wherein a coating is applied to the tapered surface or the flat surface of the piston rod. The actuator for a hood lifting device according to claim 2 or 3, wherein a coating is applied to the tapered surface or the inclined surface of the piston rod. An actuator for a hood lifting device that lifts a hood of a vehicle by moving a piston rod disposed in a cylinder by gas pressure,
an intermediary body for preventing the piston rod from moving backward is disposed between a tapered surface provided on the base end side of the piston rod and an inner peripheral surface of the cylinder;
The tapered surface has a shape that expands in diameter toward a protruding direction of the piston rod,
a plane perpendicular to the piston rod axis line or an inclined surface inclined with respect to a direction perpendicular to the piston rod axis line is provided, the plane extending radially from a tip end side of the tapered surface in the piston rod protruding direction,
A cylinder deformation suppression member is attached to an outer peripheral surface of the cylinder,
When the piston rod protrudes, the intermediate body passes through an inner region of the cylinder deformation suppression member via the cylinder ,
A plurality of the intermediate bodies are provided,
a cylinder deformation suppression member provided in a plurality of positions at intervals in a circumferential direction of the cylinder ; The actuator for a hood lifting device according to any one of claims 1 to 6 , wherein the intermediate body is a ball or a ring.

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