Vehicle body front structure

In a vehicle body front structure, an operating unit that extends upward to raise a front hood by a predetermined amount when a vehicle collides against an obstacle in front is arranged in a dashboard upper configured to introduce outside air into an interior. The operating unit is mounted in a vehicle body so as to be displaced downward by an external force acting from above after extending upward. An opening portion for drain is provided in a bottom portion of the dashboard upper. The opening portion is arranged at a position where the operating unit can be moved downward by the external force acting from above after extending upward.

TECHNICAL FIELD

The present invention relates to a vehicle body front structure that improves a dashboard upper.

BACKGROUND ART

Rainwater that has fallen onto a windshield flows from a cowl top to a dashboard upper. A vehicle body front structure with a drain unit provided on the dashboard upper is known in, for example, Japanese Patent Laid-Open No. 6-270843 (PTL 1).

In the vehicle body front structure disclosed in PTL 1, a cowl top lower panel (dashboard lower panel) is located behind the engine room, and apron upper panels (upper frames) are located on the sides of the engine room. The upper ends of the upper frames and the upper end of the dashboard lower panel are connected by a hood hinge bracket (dashboard upper). The dashboard upper is partially overlaid on the upper ends of the upper frames. A drain hole that opens outward from the upper frame is formed in each overlaid gportion.

Rainwater that has fallen onto the windshield flows to the dashboard upper via the upper portion of the dashboard lower panel and is drained from the drain holes to the outside of the upper frames. This prevents the water from flowing into the engine room and splashing electric components. However, since the drain holes are formed in the upper frames of the vehicle body frame as well, there is room for improvement from the viewpoint of ensuring vehicle body rigidity and increasing shock absorption performance at impact. For example, a measure such as increasing the plate thickness of the upper frames is necessary.

To relax the shock of the secondary impact of a walker who collides with a vehicle, an automotive safety device is recently known, which raises the rear end of the front hood of the vehicle and increases the amount of deformation of the front hood caused by the secondary impact of the walker. Such an automotive safety device includes an operating unit configured to raise and hold the front hood. The operating unit employs a direct operated actuator formed from a cylinder and a piston rod. A high-pressure gas is generated in the cylinder, thereby moving the piston rod upward and raising the front hood. The operating unit is long in the vertical direction. The lower end of the operating unit displaces downward after the secondary impact of the walker.

The dashboard upper is arranged under the rear end of the front hood. Since the operating unit is long in the vertical direction, and a through hole or concave portion configured to retract the operating unit downward after the secondary impact of the walker is needed, it is necessary to form a through hole or a concave portion largely recessed downward in the dashboard upper. That is, a gap needs to be provided between the dashboard upper and the lower end of the operating unit that displaces downward to prevent interference between them. For this reason, the layout of members such as the dashboard upper and the operating unit is limited.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

It is an object of the present invention to provide a vehicle body front structure capable of ensuring vehicle body rigidity and increasing shock absorption performance at impact without increasing the plate thickness and improving the degree of freedom of layout of members while ensuring a through hole or concave portion configured to retract the operating unit downward at a secondary impact.

Solution to Problem

According to a first aspect of the invention, there is provided a vehicle body front structure in which an operating unit that extends upward to raise a front hood by a predetermined amount when a vehicle collides against an obstacle in front is arranged in a dashboard upper configured to introduce outside air into an interior, and the operating unit is mounted in a vehicle body so as to be displaced downward by an external force acting from above after extending upward, wherein an opening portion for drain is provided in a bottom portion of the dashboard upper, and the opening portion is arranged at a position where the operating unit displaced downward can move.

As described in a second aspect of the invention, preferably, the opening portion is located to insert in advance at least part of the operating unit before extending upward.

As described in a third aspect of the invention, more preferably, the opening portion is formed into a hole shape long in a back-and-forth direction of the vehicle body, and a size of a gap between the operating unit and a rear edge of the opening portion is set to be larger than a size of a gap between the operating unit and a front edge of the opening portion.

As described in a fourth aspect of the invention, more preferably, only an upper portion of the operating unit is mounted on the vehicle body.

As described in a fifth aspect of the invention, more preferably, the opening portion is located near a hood hinge supporting the front hood.

Advantageous Effects of Invention

In the invention according to the first aspect, the operating unit is mounted in the vehicle body so as to be displaced downward by an external force acting from above after extending upward. Since the opening portion for drain is provided in the bottom portion of the dashboard upper, and the upper frame has no opening, the vehicle body rigidity and shock absorption performance at impact can be ensured without increasing the plate thickness or sectional area of the upper frame.

Since the opening portion is arranged at a position where the operating unit displaced downward can move, the operating unit after extending upward at a secondary impact directly passes through the opening portion. It is therefore possible to improve the degree of freedom of layout of members while imparting the function of ensuring a clearance to retract the operating unit downward to the dashboard upper.

In the invention according to the second aspect, the opening portion is located to insert in advance at least part of the operating unit before extending upward. Hence, the opening portion has a guide function of moving the operating unit downward.

In the invention according to the third aspect, the opening portion is formed into a hole shape long in a back-and-forth direction of the vehicle body, and a size of a gap between the operating unit and a rear edge of the opening portion is set to be larger than a size of a gap between the operating unit and a front edge of the opening portion. When the front hood displaces downward while moving to the back side of the vehicle in a collision of the front surface of the vehicle, the operating unit also moves to the back side of the vehicle along with the movement of the front hood to the back side of the vehicle. Since the gap between the operating unit and the rear edge of the opening portion is large, the operating unit does not interfere with the edge of the opening portion. For this reason, the operating unit can move downward in a desired mode after extending.

In the invention according to the fourth aspect, since only the upper portion of the operating unit is mounted on the vehicle body, the distance from the point of action to the support point is short. The deflection in the moving direction can be small, and the downward movement of the operating unit after extending is not impeded.

In the invention according to the fifth aspect, the opening portion is located near a hood hinge supporting the front hood. When arranged toward in the opening portion, the operating unit is also located near the hood hinge. Hence, the operating unit can push the mount portion of the hood hinge upward, and the rear end of the front hood can instantaneously be raised.

DESCRIPTION OF EMBODIMENTS

The best mode for carrying out the invention will now be described with reference to the accompanying drawings. Note that in this specification, “front (Fr)”, “rear (Rr)”, “left (L)”, “right (R)”, “up (Up)”, and “down (Down)” represent directions viewed from a driver.

Embodiment

A vehicle body front structure according to an embodiment of the present invention will be described first with reference to the accompanying drawings.

As shown inFIGS. 1 and 2, a vehicle10is an automobile. An engine room14storing an engine13is formed between left and right front fenders12(only the left front fender is shown) of a vehicle body11. An interior15is formed behind the engine room14.

The engine room14and the interior15are partitioned by a dashboard lower panel16and a dashboard upper17. The dashboard lower panel16is formed like an upright wall. The dashboard upper17is provided on the upper end of the dashboard lower panel16. The rear end of the dashboard upper17is connected to the lower end of a windshield18inclined to the lower front side. The dashboard upper17has a function of introducing outside air into the interior15and a function of receiving and draining rainwater and the like running down the windshield18.

The front part of the vehicle body11includes left and right upper frames21, left and right damper housings22(only the right damper housing is shown), horizontal plate-shaped damper bases22aformed on the upper ends of the left and right damper housings22, left and right wheel houses23(only the left wheel house is shown), and a front bulkhead24. The left and right upper frames21extend forward from left and right front pillars25(only the left front pillar is shown) and curve to the front side of the left and right wheel houses23. The left and right wheel houses23continue to the lower portions of the left and right damper housings22.

A front hood31that forms an automotive safety device30is arranged above the engine room14in front of the windshield18. When the vehicle10collides against an obstacle, the automotive safety device30raises the front hood31from a position indicated by an imaginary line to a position indicated by a solid line and holds the raised front hood31. The automotive safety device30will be described below in detail.

The automotive safety device30includes the front hood31that is of a front opening type and closes the upper opening of the engine room14, left and right operating units40that push the left and right rear ends of the front hood31indicated by the imaginary line and raise the front hood31to the position indicated by the solid line, and a bumper senor32that is arranged near a bumper face19and detects a collision of the vehicle10against an obstacle. The automotive safety device30further includes a control unit33that transmits an operation signal to the left and right operating units40based on a collision detection signal from the bumper senor32, and left and right hood hinges50that pivotally support the left and right rear ends of the front hood31and hold the left and right rear ends of the front hood31at the raising position indicated by the solid line at impact.

Note that the operating unit40includes components common to the left and right, and the hood hinge50includes components common to the left and right. For the sake of convenience, the left operating unit40and the left hood hinge50will be described, and a description of the right operating unit40and the right hood hinge50will be omitted. Since the left and right structures in the vehicle width direction are the same, only the members on the left side will be explained.

The front hood31is configured to open its front part using the hood hinges50on the rear part as a fulcrum for the maintenance of the engine room14in a normal state. When the front hood31is closed, a striker31aprovided at the front end of the front hood31and a latch24aprovided on the upper portion of the front bulkhead24are locked to prevent the front hood31from rising. When the front hood31is opened, an open stay24bholds the open state.

The dashboard upper17and the operating unit40will be described next.

As shown inFIGS. 3 to 5, the dashboard upper17is provided on the upper end of the dashboard lower panel16, and formed long in the vehicle width direction. The dashboard upper17is formed into a concave section opening upward when viewed from a side of the vehicle, and includes a forward downslope portion17aformed to be downslope from the rear end, a bottom portion17bextending forward from the lower end of the forward downslope portion17a, and a forward upslope portion17cformed to be upslope from the front end of the bottom portion17b. Since the dashboard upper17is formed into a concave section, the rigidity in the vehicle width direction can be improved.

Opening portions17dfor drain are provided at two ends of the bottom portion17bin the vehicle width direction. A reinforcing annular portion17eextends downward from the edge of each opening portion17d. The reinforcing annular portion17efunctions as a rib and can improve the rigidity of the bottom portion17bwithout separately providing a rib. The forward downslope portion17aallows water from the windshield18to quickly flow to the bottom portion17b. In addition, the forward upslope portion17ccan prevent water on the bottom portion17bfrom flowing into the engine room14.

Each end of the dashboard upper17in the vehicle width direction includes a portion17fbent upward. The bent portion17fis welded to the left upper frame21(seeFIG. 2). Hence, the rigidity at the two ends of the dashboard upper17in the vehicle width direction can be improved. Since the opening portions17dare formed near the bent portions17f, a decrease in the rigidity caused by the openings can be compensated for. In addition, since the opening portion17dis located outside the left damper housing22, drainage from the opening portion17dnever enters the engine room14.

The opening portions17dfor drain are provided only in the bottom portion17bof the dashboard upper17, and the upper frames21have no opening. For this reason, the vehicle body rigidity and shock absorption performance at impact can be ensured without increasing the plate thickness or sectional area of the upper frames21.

The left operating unit40is mounted on the vehicle body11, and includes an inflator41located at the lower portion of the operating unit40and having a columnar appearance, a cylinder42having a cylindrical shape and extending upward from the inflator41, a rod43movably stored in the cylinder42, and a push portion44provided at the upper end of the rod43.

The left operating unit40is formed long in the vertical direction as a whole. A support member45is provided on an upper portion42aof the operating unit40, more specifically, on the upper portion42aof the cylinder42. One end of the support member45is mounted on the vehicle body11by fastening members61, and the other end of the support member45is mounted on the vehicle body11by a fastening member62. Note that a fixing portion42bconfigured to fix the cylinder42to the support member45is formed on the upper portion42a.

More specifically, a bracket47is mounted on the left damper base22aby a fastening member63. The fastening members61,62, and63are bolts. One end of the support member45is mounted on the left upper frame21(vehicle body11) by the bolts61, and the other end of the support member45is mounted on the bracket47by the bolt62. A harness46is also fastened to the support member45by a clip. That is, since the support member45serves as both the support of the operating unit40itself and the support of the harness46, the number of components for the support can be decreased.

The left operating unit40ignites a gas generator in the inflator41to generate a gas and moves the rod43upward by the gas, thereby causing the push portion44at the distal end of the rod43to raise the rear end of the front hood31.

The opening portion17dis arranged at a position where the left operating unit40displaced downward can move. More specifically, the opening portion17dis located to insert in advance at least part of the left operating unit40before extending upward. For this reason, the left operating unit40after extending upward at a secondary impact directly passes through the opening portion17d. Since the opening portion17dfor drain is used as a clearance to retract the left operating unit40downward, the shape of the dashboard upper17need not particularly be changed. As a result, it is possible to improve the degree of freedom of layout of members while ensuring the portion to allow the downward movement of the left operating unit40.

Note that in this embodiment, part of the left operating unit40is inserted in the opening portion17din advance. However, the present invention is not limited to this. The left operating unit40may be located above the opening portion17dif the left operating unit40displaced downward can move.

The opening portion17dis formed into a hole shape long in the back-and-forth direction of the vehicle body. The size of the gap between the operating unit40and a rear edge P1of the opening portion17dis L1, and the size of the gap between the operating unit40and a front edge P2of the opening portion17dis L2. L1is set to be larger than L2.

When the front hood31displaces downward while moving to the back side of the vehicle in a collision of the front surface of the vehicle, the operating unit40also moves to the back side of the vehicle along with the movement of the front hood31to the back side of the vehicle. Since the gap between the operating unit40and the rear edge P1of the opening portion17dis large, the operating unit40does not interfere with the edge P1of the opening portion17d. For this reason, the operating unit40can move downward in a desired mode after extending.

The hood hinge50will be described next.

As shown inFIGS. 6 and 7, the left hood hinge50has the lower side mounted on the rear part of the left upper frame21of the vehicle body11by fastening members (not shown) and the upper side mounted on the front hood31by fastening members64. Note that in this embodiment, the fastening members64are bolts. However, the present invention is not limited to this, and the hood hinge may be mounted by rivets or the like. The left hood hinge50will be described below in detail.

The lower side of the left hood hinge50includes a lower mount seat51to be mounted on the left upper frame21, and a lower bracket52rising from the lower mount seat51. The upper side of the left hood hinge50includes an upper mount seat59to be mounted on the lower surface of the rear part of the front hood31, and an upper bracket58extending downward from the upper mount seat59.

In the left hood hinge50, the lower end of a first link54is swingably mounted on the lower bracket52via a first pin53, the lower end of a second link56is swingably mounted on the upper end of the first link54via a second pin55, and the upper bracket58is swingably mounted on the upper end of the second link56via a third pin57.

In a normal state, when the front part of the front hood31is opened, the upper bracket58swings about the third pin57serving as a fulcrum. In the normal opening/closing of the front hood31, the first link54and the second link56are locked by pawls54aand do not swing.

The left hood hinge50is located at the rear end in the front hood31and, on a side view of the vehicle, located on the upper back side of the vehicle with respect to the upper portion42aof the cylinder42. The push portion44of the left operating unit40is located near the left hood hinge50. The opening portion17dis located near the left hood hinge50supporting the front hood31.

When arranged toward the opening portion17d, the left operating unit40is also located near the left hood hinge50. Hence, the push portion44of the left operating unit40can push the mount portion (upper mount seat)59of the left hood hinge50upward, and the rear end of the front hood31can instantaneously be raised. The front part of the upper mount seat59is formed wide, and the wide portion can receive the push portion44. The lower surface of the front hood31is reinforced by the wide portion of the upper mount seat59. For this reason, even when abruptly pushed by the push portion44, the rear part of the front hood31can be raised by a predetermined amount without making a dent in the front hood31.

The functions of the operating unit40and the hood hinge50described above will be explained.

As shown inFIGS. 6 to 8, in a collision of the vehicle, the left operating unit40operates, and the rod43moves upward. The push portion44of the rod43abuts against the upper mount seat59and further moves upward to raise the rear end of the front hood31.

Along with the upward movement of the rear end of the front hood31, the first link54and the second link56of the left hood hinge50, which are locked by the pawls54a, are unlocked. The first link54swings about the first pin53serving as a fulcrum, the second link56swings about the second pin55serving as a fulcrum, the upper bracket58swings about the third pin57serving as a fulcrum, and the left hood hinge50extends. The support member45is not deformed by a load received when the operating unit40pushes the rear end of the front hood31upward. Hence, the cylinder42of the operating unit40is held at the initial position.

If an impact force is applied to the front hood31by an obstacle in the collision of the vehicle, the support member45deforms or ruptures and thus enables the operating unit40to move. Since only the upper portion of the left operating unit40is mounted on the vehicle body11, the distance from the point of action where the front hood31contacts up to the support point of the support member45is short. The deflection in the moving direction can be small, and the downward movement of the operating unit after extending is not impeded.

The function of the above-described vehicle body front structure will be described next.

As shown inFIG. 9(a), water flowing from the windshield18(seeFIG. 1) flows on the forward downslope portion17a, as indicated by an arrow (1), and drained from the opening portion17d, as indicated by an arrow (2).

In the collision of vehicle, the inflator41operates, and the push portion44moves upward, as indicated by an arrow (3), and abuts against the front hood31. The push portion44further moves upward, and the front hood31is raised, as indicated by an arrow (4).

As shown inFIG. 9(b), when a secondary impact occurs as the obstacle is thrown on the front hood31, the front hood31receives a downward load and moves, as indicated by an arrow (5). The rod43maintains the raised state, and the entire operating unit40starts moving downward, as indicated by an arrow (6).

As shown inFIG. 9(c), the opening portion17dis arranged at a position where the left operating unit40displaced downward can move. For this reason, the operating unit40after extending upward at the secondary impact directly passes through the opening portion17d. It is therefore possible to improve the degree of freedom of layout of members while imparting the function of ensuring a clearance to retract the operating unit downward to the dashboard upper.

If the opening portion17dis not used to ensure the clearance to retract the operating unit40downward, a measure of, for example, further recessing the bottom portion17bof the dashboard upper17downward is necessary, and the shape of the dashboard upper17becomes complex. In addition, an operating unit having a complex shape needs to be formed by shortening the length of the operating unit40in the vertical direction. In this respect, the operating unit40according to the present invention has a simple shape formed long in the vertical direction as a whole. However, since the opening portion17dis used as the clearance to retract the operating unit downward, the left operating unit40with the simple linear shape can be employed.

In addition, the opening portion17dis located to insert in advance at least part of the operating unit40before extending upward. The opening portion17dcan thus have a guide function of moving the operating unit40downward. Hence, the front hood31can be moved smoothly at the secondary impact, and the impact force can be relaxed.

The function of the vehicle body front structure in a case in which the front hood31moves to the back side of the vehicle will be described next.

As shown inFIG. 10(a), the front hood31moves to the back side of the vehicle as well, as indicated by an arrow (9), depending on the collision direction of the obstacle to the front surface of the vehicle10. For this reason, the push portion44moves to the lower back side, as indicated by an arrow (10).

As shown inFIG. 10(b), when the push portion44further moves to the back side of the vehicle, as indicated by an arrow (11), the bracket47deforms or ruptures, and the entire operating unit40moves to the back side of the vehicle, as indicated by an arrow (12). The size of the gap between the operating unit40and the rear edge P1of the opening portion17dis set to be larger than the size of the gap between the operating unit40and the front edge P2of the opening portion17d. Hence, even if the front hood31displaces downward while moving to the back side of the vehicle, the operating unit40does not interfere with the edge of the opening portion17d. For this reason, the operating unit40can move downward in a desired mode after extending. The front hood31can be moved smoothly at the secondary impact, and the impact force can be relaxed.

Note that the vehicle body front structure according to the present invention is not limited to the above-described embodiment, and changes and modifications can appropriately be made. For example, the operating unit40need not have the shape long in the vertical direction, and may have a block shape short in the vertical direction or a shape with a bent lower portion.

INDUSTRIAL APPLICABILITY

The vehicle body front structure of a vehicle according to the present invention is suitable for application of an automotive safety device by a so-called popup hood including a front hood to be raised by an operating unit.

REFERENCE SIGNS LIST