JP4371008B2 - Vehicle steering system - Google Patents

Description

  The present invention relates to a vehicle steering system, and more particularly to a steering system characterized by a mechanism for coping with a secondary collision of a driver to a steering operation member at the time of a vehicle collision.

A general vehicle steering system includes various mechanisms for coping with a driver's secondary collision with a steering operation member (for example, a steering wheel) that relies on a vehicle collision. Regarding the various mechanisms, there are techniques as described in the following patent documents. For example, Patent Literature 1 below describes a technique for pulling a steering column forward of a vehicle at an appropriate timing when a driver wears a seat belt at the time of a vehicle collision.
Japanese Patent No. 2596200 JP 2002-293251 A JP 2002-79944 A JP 2002-114156 A JP 2002-302047 A

  However, as described in Patent Document 1, it is not sufficient to alleviate the impact at the time of the secondary collision only by making the timing for pulling the steering column appropriate. Such a problem is an example of a problem of the conventional steering system, and there is room for improvement in the conventional steering system. That is, a steering system with higher practicality can be obtained by appropriately retracting the steering column. The present invention has been made in view of such circumstances, and an object of the present invention is to obtain a more practical steering system.

In order to solve the above problems, a steering system according to the present invention includes (A) a disengagement permission mechanism that allows disengagement of a steering column from a part of a vehicle body in a set disengagement direction to an impact applied to a steering operation member. A column support device that fixes and supports the steering column to a part of the vehicle body, and (B) a column pull-in device that pulls the steering column by changing the pull-in amount, which is the amount by which the steering column is pulled forward. A steering column for a vehicle, wherein the column pull-in device includes: (a) a cylinder, and a piston that is moved relative to the cylinder by the pressure of a high-pressure gas that is filled in the cylinder; And (b) change the pull-in amount of the steering column. To, characterized in that a closing mechanism for opening and closing the exhaust port provided in the cylinder for exhausting the high pressure gas in the middle movement of the piston to the outside.

  The steering system of the present invention can change the pull-in amount according to various factors that affect the impact at the time of the secondary collision, and can more effectively mitigate the driver's impact. Various aspects of the steering system of the present invention, and their operations and effects will be described in detail in the section of [Aspect of the Invention] below.

Aspects of the Invention

  In the following, some aspects of the invention that can be claimed in the present application (hereinafter sometimes referred to as “claimable invention”) will be exemplified and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is for the purpose of facilitating the understanding of the claimable invention, and is not intended to limit the combinations of the constituent elements constituting the claimable invention to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention.

In each of the following paragraphs, the combination of paragraphs (1), (7), (8), and (9) provides the technical features of claim 1 and claim 1 (2). What is added is Claim 2 and Claim 2 is added with the technical feature of (4). Claim 3 is Claim 3, and Claims 1 to 3 are any of (11) and (12). The addition of the technical features of the items corresponds to claim 4 respectively.

(1) a steering column that holds a steering operation member operably at one end;
A column support device that includes a disengagement allowance mechanism that allows disengagement of the steering column from a part of the vehicle body with respect to an impact applied to the steering operation member;
A vehicle steering system comprising: a column pulling device that pulls the steering column by changing a pulling amount that is a pulling amount of the steering column forward of the vehicle.

  The “steering operation member (hereinafter sometimes referred to simply as“ operation member ”)” in the aspect of this section is a typical steering wheel, but is not limited to a steering wheel. Various shapes are included. The “steering column” in this section is not limited in its shape and structure as long as it can hold the operating member in an operable manner and is supported by a part of the vehicle body. Specifically, a steering shaft (hereinafter sometimes simply referred to as “shaft”) having an operation member fixedly attached to one end thereof, and a steering tube (hereinafter simply referred to as “tube”) that rotatably holds the shaft. It is possible to adopt what is comprised including.

  It is desirable that the “column support device” referred to in this section supports the column on a part of the vehicle body so as not to hinder normal steering operation. In the case of the column including the shaft and the tube described above, specifically, the bracket provided on the column and the reinforcement of the instrument panel (hereinafter sometimes referred to as “instrument panel”) ( Hereinafter, it may be configured to include a support portion provided in the “instrument panel R / F”) and a member for connecting and fastening the bracket and the support portion.

  The “disengagement allowance mechanism” referred to in this section is one that allows the column to be detached from a part of the vehicle body, but is not limited to one that allows the entire column to be detached. For example, as will be described later, the column may be capable of extending and contracting, and may be configured to allow only a part of the column to be detached from a part of the vehicle body. In other words, in the description of this section, “disengagement of a column from a part of a vehicle body” is a concept including disengagement of a part of a column. Similarly, movement of a column in this specification refers to a part of a column. It is a concept that includes the movement of Further, the “separation allowance mechanism” is a mechanism that allows the column to be detached by an impact applied to the operation member. The “separation direction” is not particularly limited, and may be, for example, a structure that allows the column to be detached in the axial direction of the column, which is a general separation direction.

  The “separation allowance mechanism” may be a mechanism that allows the column to be detached from a part of the vehicle body when a certain load is applied to the column. In other words, when the load acting on the column due to the impact exceeds the set separation load, the mechanism can allow the column to be detached. Further, the separation allowing mechanism can be a mechanism that allows the column to be detached from a part of the vehicle body by releasing the column fixing or by making the separation load almost zero. The "detachment load" here is the load required for separation in the separation allowance mechanism, but in this section, the load of that magnitude when the column is detached due to a certain amount of load acting in the separation direction. It is a load defined by For example, the separation of the column may be hindered by the direction in which the impact is applied. In that case, the column may not be detached even if the component of the separation direction of the impact force exceeds the separation load. .

  The “column pull-in device” described in this section is a device that pulls the column forward so that the operation member moves away from the driver. Then, by pulling the column forward, for example, the column may be detached so that the separation load is not applied to the driver at the time of the secondary collision, and the impact of the secondary collision may be reduced. . Further, by pulling the column forward, for example, by reducing the relative speed between the driver and the operating member at the time of the secondary collision, that is, by reducing the speed of the secondary collision, the impact can be reduced. There are cases where it is possible. Further, the column pull-in device in this section can change the column pull-in amount. Therefore, the amount of pull-in can be changed according to various factors affecting the impact at the time of the secondary collision, for example, whether or not the seat belt is worn, the collision speed, the weight of the driver, etc. Can be relaxed. In that case, if the steering system is equipped with a device for reducing the impact of the driver, for example, a seat belt, an airbag, an impact energy absorbing device (described later), etc., the entire device is effective. The amount of entrainment can be changed to mitigate the impact.

  In the column pull-in, the pull-in operation by the column pull-in device is performed until the column moving distance reaches a set distance or for a set time. The column pull-in amount can be changed by changing the movement distance of the columns or the pull-in operation time. That is, the pull-in amount can be changed by, for example, an operation amount that is an amount by which the column pull-in device operates to move the column. Further, after the pulling-in operation by the column pull-in device is completed, the column is not necessarily stopped, and the column may continue to be moved by the inertial force or by the driver's inertial force. The direction in which the column is retracted is the front of the vehicle, and can be, for example, the front in the axial direction of the column or the front in the horizontal direction. Further, it is desirable that the direction in which the column is pulled in is the same direction as the above-described separation direction.

  (2) The column pulling device changes the pull-in amount of the steering column into a first pull-in amount and a second pull-in amount larger than the first pull-in amount. Steering system.

  A general steering system includes an impact energy absorbing device (hereinafter sometimes referred to as an “EA device”) that absorbs the impact energy of the driver while moving the column forward of the vehicle during a secondary collision. There are many. In general, the EA device moves the column forward of the vehicle at the time of a secondary collision to alleviate the impact of the driver, and generates resistance to the movement of the column to absorb the inertia energy of the driver. Has been. The resistance force generated by the EA device acts as an impact energy absorption load (EA load) that is a force for absorbing the impact energy. When the inertia energy of the driver at the time of the secondary collision is large, for example, when the collision speed is large, when the seat belt is not worn, or when the driver is heavy, the large inertia energy is absorbed by the EA device. Therefore, it is desirable to secure a long absorption stroke of the EA device by reducing the pull-in amount. On the other hand, when the inertia energy of the driver at the time of the secondary collision is small, it is desirable to absorb the impact more gently by increasing the pull-in amount.

  (3) The vehicle steering system according to item (2), wherein the first pull-in amount is a minimum amount required to disengage the steering column from a part of a vehicle body.

  The first pull-in amount described in this section is the minimum amount necessary for detaching the column, that is, the detachment distance. If the column is retracted by the separation distance, the column is forcibly separated from the vehicle body, so that a separation load is not applied to the driver at the time of a secondary collision, and the impact can be effectively reduced. In addition, when the steering system is equipped with an EA device, if the pull-in amount is set as a separation distance, a long absorption stroke of the EA device after the column pull-in can be secured, so that the impact at the time of the secondary collision is reduced. Large inertia energy can be absorbed. On the other hand, the second pull-in amount is made larger than the separation distance, and the EA load becomes small in the section in which the column is pulled, so that inertia energy can be absorbed more slowly.

  In addition, although different from the aspect of this section, the first pull-in amount does not completely disengage the column, for example, the pull-in amount with which a part of the disengagement distance (for example, about half) is retracted. It can be set as the mode which was made. In that aspect, the driver's impact can be mitigated by retraction, and the remaining disengagement load can be applied to absorb the driver's inertial energy.

  (4) Item (2) or (3), wherein the column retracting device is configured to retract the steering column when the seat belt is not worn, and retract the second retracted amount when the seat belt is worn. The vehicle steering system according to item.

  For example, in the aspect in which the steering system includes the EA device, by reducing the amount of pull-in when the seat belt is not worn, the impact at the time of the secondary collision can be reduced and relatively large inertia energy can be absorbed. On the other hand, by increasing the pull-in amount when wearing the seat belt, the EA load is reduced in a longer section, and even if both the restraint force of the seat belt and the EA load of the EA device are combined, the force applied to the driver is moderate It can be made to be a large size.

  (5) The vehicle steering system according to (4), wherein the steering system includes a seat belt wearing detector that detects a state in which the driver is wearing the seat belt.

(6) The steering system includes a control device that controls the column pull-in device,
The control device determines whether or not a seat belt is worn based on a detection signal of the seat belt wearing detector, and switches between the first pull-in amount and the second pull-in amount according to whether or not the belt is worn. The vehicle steering system according to item (5).

  (7) The vehicle steering system according to any one of (1) to (6), wherein the column retracting device includes an actuator as a power source for retracting the steering column.

  The configuration of the “actuator” in this section is not particularly limited, and various configurations can be adopted depending on the configuration of the column pull-in device. Specifically, suitable ones from various configurations such as ones including an electric motor, ones including an electromagnetic solenoid, ones configured to operate by fluid pressure, etc. Can be selected and adopted. In the vehicle steering system described in this section, the pull-in amount can be changed by changing the operation amount of the actuator or changing the transmission amount of the driving force of the actuator. In this case, for example, the operation amount or the transmission amount can be changed by the control device. In the case of changing the operation amount of the actuator, for example, a pull-in amount changing mechanism which is a mechanism for changing the column pull-in amount by changing the operation amount of the actuator may be provided in the column pull-in device. The operation amount can be changed by controlling the pull-in amount changing mechanism by, for example, a control device.

  (8) The vehicle steering system according to (7), wherein the actuator includes a cylinder and a piston that is moved relative to the cylinder by the pressure of a high-pressure gas that fills the cylinder.

  The mode described in this section is a mode in which the structure of the actuator is limited. If a high-pressure gas is used, the pressure source can be made relatively small as compared with those using hydraulic pressure or the like. The actuator described in this section is a cylinder device type actuator. For example, the column can be retracted by mechanically interlocking the piston and the column that are moved in the cylinder by the high-pressure gas. . The high-pressure gas can be generated by, for example, containing a gunpowder as a solid medicine inside the cylinder and burning the gunpowder. In that case, the actuator can be further reduced. Further, the high-pressure gas can be supplied from the outside, for example. When the amount of pulling is changed by changing the amount of actuation of the actuator, for example, a plurality of explosives are accommodated so that they can be individually ignited, and the amount of pulling is changed by changing the amount of explosives to be burned. Can be made. In that case, for example, the ignition to the gunpowder can be controlled by the control device.

  (9) The cylinder includes an exhaust port for exhausting the high-pressure gas to the outside during the movement of the piston, and the column retractor opens and closes to open and close the exhaust port in order to change the retracting amount of the steering column The vehicle steering system according to item (8), further comprising a mechanism.

  If the column and the piston are linked, a fixed relationship is established between the column pull-in amount and the piston movement amount, and the column pull-in amount can be changed by changing the piston movement amount. it can. That is, the mode described in this section is a mode in which the pull-in amount is changed by changing the operation amount of the actuator. The column retracting device described in this section performs the column retracting operation by reducing the pressure inside the cylinder by exhausting high-pressure gas to the outside after performing the column retracting operation for a set distance or time. Can be terminated. The exhaust port can be provided, for example, at a position where the piston passes during the stroke in the cylinder. In that case, when the exhaust port is open, the high-pressure gas is exhausted when the piston passes through the exhaust port, and the column retraction operation is completed. By doing so, the column can be retracted by the set retracting amount without detecting the moving distance of the piston (or the retracting distance of the column). On the other hand, when the exhaust port is closed, the column is continuously drawn because the piston is pushed by the high-pressure gas. A plurality of exhaust ports can be provided by changing the distance from the end of the cylinder, and the moving distance of the piston can be changed by changing the exhaust port to be opened.

  For example, the exhaust port can be provided at a position where the piston passes at an initial stage where the piston strokes, that is, at a stage where the moving distance of the piston is small. In that case, when the piston moves by a set distance or the like, the exhaust port that has been closed in advance is opened, whereby the high-pressure gas is exhausted and the column retraction is completed. By doing so, the column pull-in amount can be changed relatively easily in a plurality of steps or in a stepless manner. In the aspect described in this section, the exhaust port and the opening / closing mechanism function as the pull-in amount changing mechanism.

  (10) The vehicle steering system according to item (9), wherein the opening / closing mechanism includes an electromagnetic power source.

  The electromagnetic power source can be, for example, one having a solenoid coil, a motor, or the like, and can be switched between opening and closing relatively easily by supplying electric power.

  (11) The vehicle steering system according to any one of (1) to (10), wherein the column pulling device starts pulling operation of the steering column at the time of a secondary collision.

  The time of the secondary collision can be, for example, a time when the driver collides with the operation member or a time when it can be considered that the driver has collided with the operation member. The point of time when the operation member can be regarded as having collided with the operation member is, for example, an impact load with a magnitude exceeding the set impact load, for example, an impact load with a magnitude exceeding the impact absorption load set on the airbag is applied to the operation member. It can be the time of joining. In the case of a secondary collision, the impact load applied to the operation member is increased in a short time when the driver collides with the operation member. For example, if the time point before the impact load becomes a relatively large load is set as the time point of the secondary collision, the column can be pulled in before the impact applied to the driver becomes large, and the driver's impact can be reduced. it can. If the column pull-in operation is started at the time of the secondary collision and the column pull-in speed is set to be slower than the moving speed of the driver, the inertia energy of the driver is absorbed while the column is pulled in. be able to. As described above, by starting the column pull-in operation at the time of the secondary collision, the column can be pulled forward at an appropriate timing, and the driver's impact can be more effectively mitigated. . The time of the secondary collision can be detected based on, for example, a load applied to the operation member by the secondary collision. That is, the time point when the load applied to the operation member exceeds the set load can be regarded as the time point of the secondary collision. If the set load is a relatively small load, the column can be retracted before a large impact is applied to the driver, and the driver's impact can be reduced.

  If the steering system described in this section includes an airbag device, for example, an impact load exceeding the load set on the operation member is applied in a state where the driver collides with the operation member via the airbag. Can be regarded as the time of the secondary collision. That is, in the aspect of this section, when the driver substantially collides with the operation member, specifically, for example, the operation member is set via the airbag even if it is not in direct contact. A mode is also included in which the pulling-in operation of the column is started when an impact load exceeding the load is applied. In this aspect, for example, since the pull-in operation is not started until the set impact load is applied to the operation member, the airbag device is supported with a sufficient support load, and the airbag can effectively mitigate the impact. it can. In the steering system described in this section, even if a vehicle collision occurs, if the secondary collision does not occur, the column is not retracted. That is, the steering system of this section can avoid unnecessary operation of the column pull-in device.

  For example, the aspect described in this section may include a secondary collision detection mechanism that detects that the load applied to the operation member exceeds the set load. The secondary collision detection mechanism may have, for example, a strain detector that detects distortion due to deformation of the operation member, column, or the like, or a displacement detector that detects displacement of the operation member. In addition, the steering system may include an operation member displacement allowance mechanism that allows the operation member to be displaced forward according to an axial load applied to the operation member during a secondary collision, for example. If the operation member displacement allowance mechanism allows the operation member to be displaced against a set load or elastic force, the secondary impact is suppressed while suppressing the driver's impact from increasing. A collision can be detected.

(12) The vehicle steering system according to any one of (1) to (10), wherein the steering system includes an operation member displacement detector that detects displacement of the steering operation member at the time of a secondary collision.
(13) The steering system includes a control device that controls the column pull-in device, and the control device starts the pull-in of the steering column based on a detection signal of the operation member displacement detector. The vehicle steering system according to item (12), which controls the column pull-in device.

  The above two terms will be described. At the time of a secondary collision, the operation member can be configured to be appropriately deformed or displaced by a relatively small impact load. In that case, by detecting the displacement of the operation member by the operation member displacement detector, Secondary collision can be detected. If there is a correlation between the load applied to the operating member and the displacement of the operating member, each of the modes described in the above two items can be used as a concrete example of the secondary collision detection mechanism described in the above (11). It can be an example of an aspect showing a configuration. The function and effect in this case are the same as in the above item (11). Further, if the steering system according to the above item (12) is provided with the airbag device, the displacement of the operation member due to the collision of the driver with the airbag is detected by the operation member displacement detector, A collision can be detected. The operation member displacement detector can detect, for example, that a specific portion of the operation member has been displaced by a set amount forward of the vehicle (for example, forward in the column axis direction, forward in the horizontal direction, etc.). .

  (14) The steering system includes an impact energy absorbing device that generates an impact energy absorbing load accompanying the movement of the steering column detached from a part of the vehicle body and absorbs the energy of the impact applied to the steering operation member. The vehicle steering system according to any one of (1) to (13).

  The aspect described in this section is a system configured to include the EA device, and the impact energy is also absorbed by the apparatus. Therefore, according to the aspect described in this section, more effective shock absorption is performed. A steering system capable of The “impact energy absorbing device” described in this section is not particularly limited in specific configuration. For example, a set part includes a deformable member whose deformation is forced by the other part of the column and a part of the vehicle body as the column moves in a state of being engaged with one of the column and a part of the vehicle body. In addition, the structure can generate an impact energy absorption load (hereinafter sometimes referred to as “EA load”) depending on the deformation resistance of the deformable member. For example, a so-called impact energy absorbing plate (hereinafter sometimes referred to as “EA plate”) is employed as the deformable member. Further, when the column can be expanded and contracted, it can be configured such that a frictional force is generated in the expansion and contraction portion, and the frictional force is an EA load.

  (15) The vehicle steering system according to any one of (1) to (14), wherein the steering system includes an airbag device that is provided on the steering operation member and deploys an airbag.

  According to the aspect described in this section, since the impact energy is also absorbed by the airbag device, a steering system capable of more effective impact absorption is realized. Further, since the rate of increase of the impact load is lowered by the airbag, it becomes easy to detect the secondary collision.

  Hereinafter, after describing the force applied to the driver at the time of a secondary collision in which the driver and the steering operation member collide, some embodiments of the present invention and modifications thereof will be described in detail with reference to the drawings. In addition to the following examples, the present invention is implemented in various modes including various modes modified and improved based on the knowledge of those skilled in the art, including the mode described in the above [Mode of Invention]. be able to.

<Shock during secondary collision>
FIG. 1 a schematically shows a force applied to the driver when the driver collides with the steering operation member in a stopped state. The operation member is supported by the steering column, and the column is detached from the vehicle body and moved forward by the impact at the time of the secondary collision, and the inertia energy of the driver is obtained by the impact energy absorbing device (EA device). Shall be absorbed. In addition, when the column is detached from the vehicle body, it is assumed that the column moves against the set separation load. Therefore, at the time of the secondary collision, the impact is alleviated by the airbag in the initial stage, but when the driver directly collides with the operating member after that, a large force (Fig. At peak A) may be added to the driver and impact relaxation may be insufficient. In such a case, it is predicted that the influence of the separation load can be reduced by reducing the separation load of the column. However, although there is a certain effect by reducing the separation load, as described below, it is not sufficient to alleviate the impact.

  FIG. 1b schematically shows the force applied to the driver when the separation load is almost zero (solid line in the figure). The state where the separation load is 0 is, for example, a case where the column movement is released after the collision, and it is assumed that the column can be separated with almost no resistance. However, although the separation load is 0, the peak B remains although it is smaller than the peak A. This is due to the inertia force of the operation member and the column, that is, the reaction force of the column or the like that is rapidly accelerated by the driver colliding with the operation member is applied to the driver. If such a peak is lowered so that the force applied to the driver changes gently (broken line in the figure), it is considered that the impact can be effectively mitigated. For this purpose, it is effective to pull the column forward of the vehicle at the time of the secondary collision. This is because by reducing the relative speed between the driver and the column or the like, the acceleration of the column or the like can be reduced and their reaction force can be reduced.

  As described above, by pulling the column before the force applied to the driver (impact load) becomes large (at the time of secondary collision), the influence of inertial force can be reduced, and the impact can be effectively reduced. Can be relaxed. Further, when there is a separation load, by pulling the column, it is possible to suppress the reaction force due to the separation load from being applied to the driver, and the impact can be effectively mitigated. In addition, after the column is detached, the movement resistance force by the EA device, that is, the impact energy absorption load (EA load) acts on the column, and the force resulting from the resistance force is operated as the EA load via the column and the operation member. Join.

  Next, how the force applied to the driver changes depending on whether or not the seat belt is worn will be described. In a general vehicle, even when a seat belt is not worn, the impact of the driver is absorbed by the airbag and the EA device. For example, the EA load generated by the EA device is sized so as to absorb the inertia energy of the driver who does not wear the seat belt at the time of the secondary collision. On the other hand, when a seat belt is worn, the restraint force of the seat belt is applied to the driver after the collision of the vehicle. The seat belt restrains the driver with a substantially constant tension, and is pulled out as the driver falls forward. When wearing a seat belt at the time of a secondary collision, the force from the operating member and the restraint force of the seat belt are combined and applied to the driver, and the force applied to the driver is excessive. There is a risk of becoming. Therefore, when the seat belt is worn, the amount of pull-in of the column is increased, and not only the detachment load and inertial force but also the EA load is reduced in the section where the column is retracted after detachment, thereby The combined force can be set to an appropriate magnitude, and the driver's impact can be effectively mitigated.

<First embodiment>
FIG. 2 shows the overall configuration of the steering system of this embodiment. The present steering system is configured with a steering column 10 as a main body, and the column 10 is a pair of column mounting brackets (hereinafter sometimes abbreviated as “mounting brackets”) provided on the instrument panel R / F 12. 14 is fixedly supported by a part of the vehicle body. In the supported state, the column 10 is arranged in an inclined posture so that the front side of the vehicle is positioned downward as shown in the drawing. The column 10 mainly includes a column main body 20, a breakaway bracket (hereinafter sometimes abbreviated as “B.A.BKT”) 22 provided at an intermediate portion in the axial direction of the column main body 20, and a front portion. The B. A. BKT 22 and the front bracket 24 are each attached to the mounting bracket 14 so that the column 10 is installed at two locations. It is supported.

  The column 10 is supported in a state in which a rear portion protrudes from the instrument panel 30 toward the rear of the vehicle, and a steering wheel 32 as a steering operation member is attached to the protruding rear end portion. Is configured to hold the steering wheel 32 in an operable manner. Incidentally, the steering wheel 32 is provided with an airbag device 34. A portion protruding from the instrument panel 30 of the column 10 is covered by a column cover 36, and a lower part is covered by an instrument panel lower cover 38. The front end portion of the column 10 is connected to a steering device existing outside the vehicle compartment via an intermediate shaft (not shown).

  3 is a side view of the column 10, FIG. 4 is a plan view, FIG. 5 is a side cross-sectional view, and FIG. 6 is a perspective view of a part B.A.BKT22. 3 to 5, the right end is the vehicle rear side (steering wheel 32 side), and the left side is the vehicle front side. As shown in FIG. 2, since the column 10 is attached to the vehicle in an inclined state, the right end in FIGS. 3 to 5 is actually located obliquely above the rear of the vehicle, and the left end is the front of the vehicle. Located diagonally below. In the present embodiment, to simplify the description, unless otherwise specified, the right side in these figures is “vehicle rear side” or simply “rear side”, and the left side is “vehicle front side” or simply “front side”. The direction toward the right side is referred to as “vehicle rear” or simply “rear”, and the direction toward the left side is referred to as “vehicle front” or “front”.

  The column body 20 includes a shaft portion and a tube portion that supports the shaft portion in a state where the shaft portion is inserted. The shaft portion includes a rear shaft 50 positioned on the vehicle rear side and a front shaft 52 positioned on the vehicle front side. The rear shaft 50 is formed in a pipe shape, the front shaft 52 is formed in a rod shape, and the rear portion of the front shaft 52 is inserted into the front portion of the rear shaft 50. Splines that mesh with each other are formed on the front inner peripheral surface of the rear shaft 50 and the rear outer peripheral surface of the front shaft 50, respectively. The rear shaft 50 and the front shaft 52 are capable of relative movement in the axial direction and are capable of relative rotation. Connection is impossible. Moreover, the tube part is comprised including the rear part tube 54 located in the vehicle rear side, and the front part tube 56 located in the vehicle front side. The rear tube 54 and the front tube 56 are both pipe-shaped, and the rear portion of the front tube 56 is inserted into the front portion of the rear tube 54. A pipe-like liner 58 is provided on the inner surface of the front portion of the rear tube 54, and the front tube 56 is inserted into the rear tube 54 without rattling through the liner 58. The inner peripheral surface of the liner 58 that comes into contact with the outer peripheral surface of the front tube 56 is subjected to anti-friction treatment, and the relative movement in the axial direction between the rear tube 54 and the front tube 56 is facilitated. Further, radial bearings 60 and 62 are respectively provided at the rear end portion of the rear tube 54 and the front end portion of the front tube 56, and the rear tube 54 and the front tube 56 are respectively connected via the radial bearings 60 and 62. Each of the rear shaft 50 and the front shaft 52 is rotatably supported at an intermediate portion thereof. With such a structure, the column main body 20 can be expanded and contracted.

  The column body 20 is attached to a part of the vehicle body in each of the rear tube 54 and the front tube 56. The front bracket 24 described above is fixedly provided at the front end of the front tube 56, and a shaft insertion hole 66 is provided in the front bracket 24. A bearing member 70 having a shaft hole 68 is fixed to each of the pair of mounting brackets 14 provided in the instrument panel R / F 12. The shaft insertion hole 66 of the front bracket 24 and these bearing members 70 are fixed. By inserting the support shaft 72 into the shaft hole 68, the column body 20 is supported so as to be swingable about the support shaft (see FIG. 2). On the other hand, the rear tube 54 is held by the B.A.BKT 22, and the B.A.BKT 22 is attached to the pair of mounting brackets 14, thereby being supported by a part of the vehicle body. More specifically, a held member 80 is fixedly provided on the rear tube 54, and the held member 80 forms a channel shape (a U-shape) that is a constituent part of the B.A.BKT 22. While being held by the holding member 82, the supported plate 84, which is another component of the B.A.BKT 22, is assembled to the pair of mounting brackets 14, so that the rear tube 54 is supported by a part of the vehicle body. The Since the mounting structure of the B.A.BKT 22 to the mounting bracket 14 will be described in detail later, the description here is reserved for the time being. Incidentally, in the attached state, the B.A.BKT 22 is released from the attached state when a load in the detaching direction exceeding the set detaching load is applied to the column 10, and the attached state is released. It is structured to be detached in the axial direction (separation direction).

  The column 10 includes a tilt mechanism 90 and a telescopic mechanism 92. Specifically, a structure that holds the column main body 20 by the B.A.BKT 22 constitutes the tilt mechanism 90 and the telescopic mechanism 92. . The holding member 82 of the B.A.BKT 22 and the held member 80 fixed to the column main body 20 have long holes 94 and 96 that intersect with each other. A shaft member 98 is inserted into the shaft. Thereby, the column main body 20 can be swung around the support shaft by the length of the long hole 94 provided in the holding member 82, and by the length of the long hole 96 provided in the held member 80, It can be stretched. FIGS. 3 and 4 show the lock lever 100 of the tilt mechanism 90 and the telescopic mechanism 92. When the lock lever 100 is pushed up (the position indicated by the solid line in FIG. 3), the held member 80 is held by the holding member 82. So that the swinging position and the expansion / contraction position of the column main body 20 are fixed. The adjustment of the position is performed by releasing the lock by depressing the lock lever 100 (the position of the two-dot chain line in FIG. 3). 2 to 5, the vehicle rear end of the column main body 20 is positioned at the uppermost position by the tilt mechanism 90, and the vehicle rear side portion of the column main body 20 is positioned at the most forward position by the telescopic mechanism 92. Is shown.

  As described above, when a load in the detachment direction exceeding the set detachment load acts on the column 10, the B.A.BKT 22 is detached from the mounting bracket 14 provided on the instrument panel R / F 12, thereby the column 10. The rear portion of the vehicle, more specifically, the rear portion of the column body 20 including the rear shaft 50 and the rear tube 54 and the B.A.BKT 22 (hereinafter sometimes referred to as “column moving portion”) are From a part, the column 10 is detached in the separation direction (the direction of the white arrow in FIG. 2) which is the axial direction of the column 10. The part from which the column 10 is detached moves in the movement direction (the direction of the thick arrow in FIGS. 2 to 5) which is substantially the same as the separation direction with the contraction of the column main body 20. The end point of the movement range of the column moving part is defined by the upper end of the front shaft 52 coming into contact with the inner surface portion where the inner diameter of the rear shaft 50 is small.

  The present steering system includes two impact energy absorbing devices that absorb the impact energy of the secondary collision in accordance with the movement of the column moving unit that is detached from the mounting bracket 14. Each of the two impact energy absorbing devices has a structure that generates a drag force in a direction that prevents the movement of the column moving portion, that is, an impact energy absorbing load (EA load), and the EA load. The impact energy is absorbed by allowing the column moving portion to move in the presence of. FIG. 6 shows a perspective view of the main part of the first EA device 110 which is one of the two impact energy absorbing devices. As a supplement to this figure, FIG. 7 is an enlarged view of a portion where the main part of the first EA device 110 in FIG. 6 is shown.

  The first EA device includes an impact energy absorbing plate (EA plate) 112 as a deforming member, and a pressing roller 114 as a deformation forcing member forcing deformation of the EA plate 112. The EA plate 112 functions as an impact energy absorbing member that generates an impact energy absorbing load, and is attached to a substantially central portion of the BAKT 22 in the vehicle width direction. The pressing roller 114 is made of a thick tubular resin and is rotatably supported by a roller shaft 118 supported by a pair of shaft support members 116 provided at the front end portion of the B.A.BKT 22. Yes.

  The EA plate 112 is made of a band-shaped metal material, and is formed by being bent in a generally U shape. The EA plate 112 is in a state where the outer peripheral surface of the pressing roller 114 is in contact with the inner side of the curved portion 120, and the upper plate portion 122 connected to the curved portion 120 is supported on the upper surface of the supported plate 84 constituting the B.A.BKT 22. In this state, the lower plate portion 124 that extends in the front-rear direction of the vehicle and is connected to the bending portion 120 is below the upper plate portion of the holding member 82 that constitutes B.A.BKT22. It extends in the front-rear direction of the vehicle in a substantially parallel state. The B.A.BKT 22 is provided with square holes 126, and a pair of holding pieces 128 formed by bending in a U-shape sandwich the EA plate 112 on both sides of the square holes 126. The holding piece 128 positions the EA plate 112 and ensures proper deformation of the EA plate 112.

  Further, the rear end portion of the upper plate portion 122 is bent upward at a substantially right angle and is an engaging portion 130 formed in a generally T shape. In a state where the column 10 is supported by a pair of mounting brackets 14 provided on the instrument panel R / F 12, the engaging portion 130 has a recess 134 of a locking bar 132 whose both ends are fixed to each of the mounting brackets 14. When the column moving part is disengaged, it is locked by the locking bar 132 (see FIG. 8). Note that two stoppers 136 are provided on the upper surface of the supported plate 84 to lock the rear end portion of the upper plate portion 122, and the movement of the EA plate to the vehicle rear side is prohibited by these stoppers 136. ing.

  When the detached column moving part moves forward in the column axis direction (in the direction of the thick arrow in FIG. 7) due to the secondary collision of the driver, the engaging part 130 is locked by the locking bar 132 on the EA plate 112. In this state, the bending portion 120 is pushed forward by the pressing roller 114. Accordingly, the bending portion 120 is deformed so that the position of the bending portion 120 on the EA plate 112 changes while maintaining the shape of the bending portion 120 substantially. The force required for the deformation, that is, the deformation resistance is set as the EA load, and the impact energy of the secondary collision is absorbed by the column moving portion moving in the presence of the EA load.

  The second EA device 150, which is another impact energy absorbing device, is provided in the telescopic portion of the tube portion. Specifically, on the outer peripheral surface of the front tube 56, three ridges 152 extending in the axial direction are formed in front of the front end portion of the rear tube 54. The three ridges 152 are formed at three equal positions in the circumferential direction, and each is formed at a height that slightly protrudes from the inner peripheral surface of the rear tube 54. Therefore, when the detached column moving portion moves, the column main body 20 contracts while the front end portion of the rear tube 54 crushes the three convex strips 152. The force required for the deformation of the three ridges 152 functions as an EA load, and the column moving portion moves in the presence of the EA load, and the impact energy is absorbed.

  Next, the attachment structure of the B.A.BKT 22 to the attachment bracket 14 that is reserved in the above description will be described with reference to FIGS. 8 shows a perspective view from the front side of the vehicle showing a state in which the column 10 is attached to the mounting bracket 14, FIG. 9 shows a cross section in that state, and FIG. 10 shows a perspective view in which the mounting structure is disassembled. Yes.

  The supported plate 84 of the B.A.BKT 22 is provided with slit holes 160, which are a composite of holes and slits, at both ends in the vehicle width direction. In the slit hole 160, each of the pair of mounting brackets 14 is provided with a mounting hole 164 in a lower collar portion 162 that constitutes a lower surface wall. The supported plate 84 and the lower flange portion 162 of the mounting bracket 14 each function as a member to be fastened, and these are the slit hole 160 (specifically, the hole portion 161 formed at the front end portion thereof) and the mounting hole 164. The B.A.BKT 22 is attached to the mounting bracket 14 by being fastened by a bolt 166 and a nut 168 as fastening means.

  A resin spacer 172 made of resin is interposed between the upper surface of the supported plate 84 and the lower surface of the lower flange portion 162 of the mounting bracket 14. The resin spacer 172 has protrusions 176 at each of the four corners on the upper surface side, and an annular boss 180 that extends downward from the periphery of the bolt insertion hole 178 on the lower surface side. Further, a collar 182 with a flange is fitted from the lower surface side of the supported plate 84, and the bolt 166 and the nut 168 are the lower flange portion 162, the resin spacer 172, the supported plate 84, the collar with the flange of the mounting bracket 14. 182 is sandwiched and fastened. The outer diameter of the boss 180 of the resin spacer 172 is slightly smaller than the inner diameter of the hole 161 of the slit hole 160 of the supported plate 84, and the inner diameter is slightly larger than the outer diameter of the flanged collar 182. Further, the front end portion of the flanged collar 182 is in contact with the lower surface of the lower collar portion 162, and the tightening margin is limited.

  In a state of being fastened by the bolt 166 and the nut 168, each protrusion 176 of the resin spacer 172 is crushed and elastically deformed, and the supported plate 84 and the lower flange portion 162 of the mounting bracket 14 are subjected to the elastic force. It is in a state of being fastened by the relying fastening force, and the relative movement between the supported plate 84 and the lower flange portion 162 of the mounting bracket 14 is limited by the frictional force generated by the fastening force. Incidentally, the slit portion 184 of the slit hole 160 provided in the supported plate 84 extends in the vehicle front-rear direction and opens to the vehicle rear side, and its width is made larger than the outer diameter of the collar 182 with the flange. The outer diameter of the boss 180 of the resin spacer 172 is smaller. Therefore, a load that exceeds the frictional force in the vehicle front direction and in a direction parallel to the upper surface of the supported plate 84 and the lower surface of the lower flange portion 162 of the mounting bracket 14 (the axial direction of the column) When acting on the supported plate 84, the movement of the supported plate 84 relative to the mounting bracket 14 is allowed. Although the boss 180 of the resin spacer 172 is broken during the movement, the force required for the break is assumed to be negligibly small.

  Due to such a structure, in the steering system of the present embodiment, the lower flange portion 162 of the mounting bracket 14, the supported plate 84, the resin spacer 172, the collar 182 with a flange, and the bolt 166, which are components constituting the mounting structure. A column support device 200 that includes the nut 168 and the like and that holds the column 10 to a part of the vehicle body is configured. In this embodiment, the mounting structure is provided at two locations, and the column support device 200 is configured by the mounting structures at the two locations. Further, the column support device 200 has a structure in which the detachment load is determined depending on the frictional force. The column support device 200 is set when a load exceeding the detachment load is applied. A mechanism that allows the separation of the column 10 (specifically, the column moving portion) in the column axis direction that is the separation direction, that is, a separation permission mechanism 202 is provided.

  FIG. 11 shows a column retracting device 300 that is a device for retracting the column 10 (specifically, the column moving portion) to the front of the vehicle and the periphery thereof. As described above, the column moving unit is supported so as to be detached from the vehicle body by the column support device 200, and by applying a force in the separating direction by the column retracting device 300, the column moving unit is forcibly detached and the front of the vehicle Can be drawn into. FIG. 12 shows a cross-sectional view of the column pull-in device 300. The column drawing device 300 includes a cylinder device 302 as an actuator and an opening / closing mechanism 304 that opens and closes an exhaust port of the cylinder device 302. In the present embodiment, the cylinder device 302 is disposed substantially parallel to the axis of the column 10 above the column main body 20.

  The cylinder device 302 includes a cylinder 316 functioning as a housing, a piston 318 inserted into the cylinder 316, a piston rod 320 having one end fixed to the piston 318 and the other end protruding from the cylinder 316 toward the vehicle rear side. It is comprised including. An end member 322 provided with a shaft hole is fixed to an end of the cylinder 316 on the vehicle front side, and the cylinder 316 is a support shaft that supports the front bracket 24 on the bearing member 70 at the end member 322. 72 is pivotally supported. In addition, a pair of brackets 324 are attached to the end of the B.A.BKT 22 on the vehicle front side at a position between which the two shaft support members 116 are sandwiched. An axis 326 is passed. A rod head 328 having a shaft hole is fixed to an end of the piston rod 320 on the vehicle rear side, and the piston rod 320 is pivotally supported by a rod support shaft 326 in the rod head 328. The piston 318 is positioned with a relatively narrow space between the end of the cylinder 316 on the vehicle rear side, and the space is filled with the explosive 330 that is a solid medicine. 3 to 6 and the like, the column drawing device 300, the pair of brackets 324, and the like are not shown so that the drawings are not complicated.

  The cylinder device 302 is provided with a first exhaust port 350 and a second exhaust port 352 for exhausting high-pressure gas. Further, a cylindrical shutter ring 360 is fitted on the outer periphery of the cylinder device 302 so as to be slidable in the axial direction while maintaining a set clearance so as to close the first exhaust port 350. The shutter ring 360 is connected to a drive shaft 364 of a solenoid 362 that is an electromagnetic power source fixed to the outer periphery of the cylinder device 302, and is slid in the axial direction by the solenoid 362. The solenoid 362 has a coil and a permanent magnet inside, and the drive shaft 364 extends when electric power is supplied in a predetermined direction, and the drive shaft 364 is retracted when electric power is supplied in the opposite direction. Has been. 11 and 12 show a state in which the first exhaust port 350 is closed while the drive shaft 364 is retracted. When the drive shaft 364 extends, the shutter ring 360 is moved to the vehicle rear side (right side in the drawing) in the axial direction, the first exhaust port 350 is opened, and the inside of the cylinder 316 is in communication with the outside. .

  The cylinder device 302 operates by igniting the explosive 330 with a spark electrode (not shown). The gunpowder 330 generates high-pressure gas by ignition, and the piston 318 moves toward the front side of the vehicle by the pressure. The movement of the piston 318 causes the B.A.BKT 22 to be pulled toward the front side of the vehicle with a force exceeding the separation load by the separation allowing mechanism 202, and the column moving portion is forced from the mounting bracket 14 toward the front of the vehicle. You can leave.

  If the first exhaust port 350 is opened when the cylinder device 302 is operated, the high-pressure gas is exhausted from the first exhaust port 350 when the piston 318 passes through the first exhaust port 350. As a result, the pressure inside the cylinder 316 decreases, so that the propulsive force does not act on the piston 318. That is, when the piston 318 passes through the opened first exhaust port 350, the pull-in operation by the column pull-in device 300 ends. On the other hand, as shown in FIGS. 11 and 12, when the first exhaust port 350 is closed, the high-pressure gas is not exhausted even if the piston 318 passes through the first exhaust port 350, and the piston 318 continues to move. Be made. When the piston 318 passes through the second exhaust port 352, the high-pressure gas is exhausted from the second exhaust port 352, and the pressure inside the cylinder 316 decreases, so that the propulsive force does not work on the piston 318. That is, when the piston 318 passes through the second exhaust port 352, the retracting operation by the column retracting device 300 ends.

  The first exhaust port 350 has a piston 318 moving distance when the column 10 (more specifically, the column moving portion) becomes equal to the separation distance that is necessary for the separation of the column 10 from a part of the vehicle body. It is provided at a position passing through the first exhaust port 350. Therefore, when the moving distance of the piston 318 becomes equal to the separation distance, the high-pressure gas is exhausted from the first exhaust port 350 and the drawing operation is completed. That is, the column pull-in amount when the first exhaust port 350 is opened is the pull-in amount (a kind of “first pull-in amount”) to be moved by the minimum distance (for example, about 10 mm) necessary for detachment of the column. It becomes. In this embodiment, the separation distance of the column moving part is substantially equal to the length dimension of the resin spacer 172 in the column axis direction. On the other hand, the second exhaust port 352 passes through the second exhaust port 352 when the moving distance of the piston 318 becomes equal to the combined distance of the separation distance and the half of the absorption stroke of the EA device. It is provided in the position to do. Therefore, when the first exhaust port 350 is closed, the column moving unit moves the distance (for example, about 60 mm) that is the combined distance of the separation distance and the half of the absorption stroke (for example, about “60th”). (It is a kind of “two pull-in amount”).

  In the present embodiment, the pull-in amount changing mechanism that changes the pull-in amount by the column pull-in device 300 includes the first exhaust port 350 and the opening / closing mechanism 304. Furthermore, an opening / closing mechanism similar to the opening / closing mechanism 304 can be provided to open / close the second exhaust port 352, and in that case, the amount of pull-in can be changed in three stages. In this case, the pull-in amount changing mechanism includes the first exhaust port 350, the opening / closing mechanism 304, the second exhaust port 352, and the opening / closing mechanism.

  In the steering system of this embodiment, the column pull-in device 300 is operated by a steering electronic control unit (ECU) 400 that is a control device (see FIG. 2). The ECU 400 is a computer-based device that controls the column pull-in device 300 by executing a column pull-in control program. The ECU 400 is connected to each of the spark electrode of the cylinder device 302 and the solenoid 362 of the opening / closing mechanism 304 of the column pull-in device 300, and is operated by receiving power from a drive circuit provided in the ECU 400. ing. Further, the vehicle is provided with various sensors, and the ECU 400 changes the column pull-in amount based on signals from those sensors, and pulls the column moving unit at an appropriate timing. More specifically, the sensor includes a vehicle collision sensor (CS) 402 as a vehicle collision detector that detects a vehicle collision, and a seat belt wearing detector that detects a state in which the driver is wearing the seat belt. Are provided, such as a seat belt sensor (SS) 404 and a displacement sensor 406 as an operation member displacement detector for detecting displacement of the steering wheel 32 (see FIG. 2).

  The displacement sensor 406 includes a lever 408 that is rotatably held. When the lever 408 is rotated, an internal switch is closed to cause conduction, and a detection signal is output to the ECU 400. The displacement sensor 406 is provided on the column cover 36 so as to face the lower portion of the front end surface of the boss portion 420 of the steering wheel 32. In the event of a secondary collision, the lower part of the steering wheel 32 is pushed forward by the driver and the steering wheel 32 and the rear shaft 50 are deformed. Therefore, the lower part of the front end face of the boss part 420 and the column cover The distance from 36 is reduced, and the displacement of the steering wheel 32 is detected. The displacement sensor 406 is also arranged so that the lever 408 is separated from the boss portion 420 by a set distance, and when the steering wheel 32 is displaced by a set amount, the lever 408 is pushed to rotate, and the steering wheel 32 The displacement is detected. The column cover 36 is attached to the rear tube 54 of the column 10, and the relative position between the displacement sensor 406 and the boss portion 420 even if the position of the steering wheel 32 is changed by the tilt mechanism 90, the telescopic mechanism 92, or the like. The relationship is kept unchanged.

  Whether or not the seat belt is worn is acquired by the ECU 400 based on a detection signal of the seat belt sensor (SS) 304. When the seat belt is worn, the shutter ring 360 is positioned at a position covering the first exhaust port 350, and the first exhaust port 350 is closed. On the other hand, when the seat belt is not worn, the shutter ring 360 is retracted and the first exhaust port 350 is opened. When the displacement sensor 406 detects that the displacement amount of the steering wheel 32 has reached the set displacement amount after the vehicle has collided forward and the vehicle collision sensor (CS) 302 detects the vehicle collision, It is detected that a secondary collision has occurred, the cylinder device 302 is operated, the column 10 (specifically, the column moving part) is pulled in, and the impact applied to the driver is alleviated.

  In this embodiment, the amount of displacement of the steering wheel 32 is correlated with the force applied to the steering wheel 32, that is, the magnitude of the load, and when the load applied to the steering wheel 32 exceeds a certain magnitude, the amount of displacement at that time Exceeds the set displacement. The steering system of the present embodiment includes an airbag device 34. When a driver collides with the airbag and a load exceeding the load set via the airbag is applied to the steering wheel 32, the displacement of the steering wheel 32 is applied. A secondary collision is detected when the amount exceeds the set displacement amount. That is, the time point at which the displacement amount of the steering wheel 32 exceeds the set displacement amount is regarded as the time point of the secondary collision. In this embodiment, the steering wheel 32 and the rear shaft 50 are configured to be appropriately deformed at the time of the secondary collision, and the operation member displacement allowance mechanism is configured including the steering wheel 32 and the rear shaft 50. Yes. In this embodiment, a secondary collision detection mechanism that includes the steering wheel 32, the rear shaft 50, and the displacement sensor 406 and detects a secondary collision based on the displacement of the steering wheel 32 is configured. In the case of a secondary collision, the load applied to the steering wheel 32 increases in a short time, but in this embodiment, the displacement amount of the steering wheel 32 when the load is relatively small is set as the set displacement amount. Therefore, the column moving part can be pulled forward together with the steering wheel 32 before a relatively large impact is applied to the driver.

  When the seat belt is not worn, the first exhaust port 350 is opened, and the pull-in amount of the column 10 is made equal to the pull-in amount (a kind of first pull-in amount). After the airbag collision, the column 10 is retracted to reduce the relative speed between the driver and the steering wheel 32 (that is, the collision speed), and the impact when the driver directly collides with the steering wheel 32 is reduced. The Further, since the pull-in operation by the column pull-in device 300 is terminated after the column moving part is detached, the inertia energy of the driver is absorbed by a sufficient EA load.

  On the other hand, when the seat belt is worn, the first exhaust port 350 is closed, and the pull-in amount of the column 10 is equal to the sum of the separation distance and the half of the absorption stroke of the EA device (the second pull-in amount). Be a kind). After the airbag collision, the column moving part is pulled in, the collision speed between the driver and the steering wheel 32 is reduced, and the impact is alleviated, similar to when the seat belt is not worn. However, since the first exhaust port 350 is closed, the pull-in operation by the column pull-in device 300 continues even after the column moving unit is detached. The column 10 after detachment is adapted to move against the EA load by the EA devices 110 and 150, but the EA load is reduced by the pulling by the column pulling device 300. In addition to the restraining force of the seat belt, a reaction force from the steering wheel 32 due to the EA load is applied to the driver wearing the seat belt, but the EA load decreases while the retracting operation is performed as described above. Therefore, the force applied to the driver is not excessive, and the inertia energy can be absorbed gently. When the driver's moving speed is slow, for example, when the seat belt is worn and the collision speed is low, the pulling speed of the column 10 may be faster than the driver's moving speed. Since the inertial energy of the driver can be sufficiently absorbed by the seat belt, the inertial energy of the driver can be absorbed more gradually as the EA load is smaller. That is, in that case, the impact is more effectively mitigated by reducing the EA load to 0 by pulling in the column 10.

  As described above, the amount of force applied to the driver from the device (seat belt, EA device, etc.) that reduces the impact by changing the pull-in amount of the column 10 depending on whether the seat belt is worn or not is moderate as a whole. Therefore, the driver's impact can be mitigated more effectively.

<Second embodiment>
In the above embodiment, the secondary collision is detected by the displacement sensor 406 provided on the column cover 36, but the displacement sensor 406 can be provided at a place different from the above. Since the steering system of the present embodiment has substantially the same configuration as that of the system of the first embodiment, the description will focus on different configurations, and the description of the same configurations will be omitted. In the description of this embodiment, components having the same functions as those of the system of the first embodiment are indicated by corresponding reference numerals, and the description thereof is omitted or simplified. To do.

  FIG. 13 is an enlarged side cross-sectional view of a rear portion of the steering column 500 (hereinafter sometimes abbreviated as “column”). In this embodiment, the rear shaft 510 is held by the rear tube 512 so as to be movable forward. That is, the front side of the bearing 60 of the rear shaft 510 is made larger in diameter than the inner diameter of the bearing 60, and the backward movement is prohibited. On the other hand, the portion of the rear shaft 510 on the rear side of the bearing 60 can be fitted with the bearing 60 relatively gently, so that the forward movement is allowed. A retaining ring 520 is attached to the rear shaft 510 at a portion spaced apart from the bearing 60 in the axial direction. Between the retaining ring 520 and the bearing 60, a compression coil spring 522 (hereinafter, may be abbreviated as “spring”) as an elastic member is provided. The spring 522 is sandwiched between the bearing 60 and the retaining ring 520 while being compressed by a set amount, and urges the rear shaft 510 rearward. The urging force is such that the rear shaft 510 hardly moves in the axial direction even when the steering wheel 32 is operated during traveling or the like.

  A displacement sensor 530 is fixed to the outer peripheral surface of the rear tube 512. The displacement sensor 530 has the same configuration as the displacement sensor 406 of the above-described embodiment, and includes an arm 532 that is rotatably held. When the arm 532 is rotated, an internal switch is closed and conduction is generated. The detection signal is output to the ECU 400. Further, the displacement sensor 530 is connected to the ECU 400. The rear tube 512 is provided with a through hole 536, and the arm 532 of the displacement sensor 530 extends through the through hole 536 to the inside of the rear tube 512. A collar 540 is fitted and fixed to the outer periphery of the rear shaft 510.

  When the rear shaft 510 is pushed forward against the urging force of the spring 522 during the secondary collision, the collar 540 rotates the arm 532 and the switch in the displacement sensor 530 is turned on. Then, the occurrence of the secondary collision is detected by the ECU 400, the column retracting device 300 is operated, and the column 500 (specifically, the column moving unit) is retracted forward of the vehicle. In other words, in this embodiment, the time when the load applied to the rear shaft 510 exceeds the set load is regarded as the time of the secondary collision. In the steering system of the present embodiment, the secondary collision can be achieved by changing the elastic coefficient of the spring 522, preload (the elastic force generated by the spring 522 in a state of being sandwiched between the bearing 60 and the retaining ring 520 in a normal state), and the like. The load applied to the rear shaft 510 when this is detected can be changed.

  In this embodiment, the operating member displacement allowance mechanism is configured including the retaining ring 520, the bearing 60, and the spring 522. The operation member displacement allowance mechanism allows the rear shaft 510 to be displaced forward in the axial direction in accordance with an axial load applied to the steering wheel 32. Further, a secondary collision detection mechanism is configured including the displacement sensor 530 and the collar 540. About operation | movement except the above-mentioned, an effect | action and effect, it is the same as that of the said Example.

<Third embodiment>
In the above embodiment, the column pull-in device 300 is provided between the B.A.BKT 22 and the front bracket 24. However, a column pull-in device having a different aspect may be provided behind the B.A.BKT 22. FIG. 14 shows a mounting state of the steering column to the mounting bracket in the steering system of the third embodiment. FIG. 14 is a side view of the steering column as seen from the left side of the vehicle, and the cylinder device is a sectional view. Since the steering system of the present embodiment has substantially the same configuration as that of the system of the first embodiment, the description will focus on different configurations, and the description of the same configurations will be omitted. In the description of this embodiment, components having the same functions as those of the system of the first embodiment are indicated by corresponding reference numerals, and the description thereof is omitted or simplified. To do.

  In this embodiment, the column pull-in device 600 is fixed and supported on the lower surface of the support bar 604 passed to the pair of mounting brackets 14. The column pull-in device 600 includes a cylinder device 608 and an opening / closing mechanism 610 as in the first embodiment. The cylinder device 608 includes a cylinder 616 functioning as a housing, a piston 618 inserted into the cylinder 616, and a piston rod having one end fixed to the piston 618 and the other end protruding from the cylinder 616 to the front side of the vehicle. 620 and a plunger head 622 fixedly attached to the other end of the piston rod 620. The piston 618 is positioned with a relatively narrow space between the end portion on the vehicle rear side inside the cylinder 616, and the space is filled with explosive 624 which is a solid medicine. The front end of the plunger head 622, which is the end on the front side of the vehicle, is brought into contact with the end of the holding member 82 and the supported plate 84 of the B.A. ing.

  Similar to the cylinder device 302 of the first embodiment, the cylinder device 608 is provided with a first exhaust port 350 and a second exhaust port 352 for exhausting high-pressure gas. Since the opening / closing mechanism 610 is the same as the opening / closing mechanism 304 of the first embodiment, the same reference numerals are given and description thereof is omitted. The description of the first exhaust port 350 and the second exhaust port 352 is the same as that of the opening / closing mechanism 304 of the first embodiment. Note that each of the cylinder device 608 and the opening / closing mechanism 610 is connected to the ECU 400 as in the first embodiment.

  The cylinder device 608 operates by igniting the explosive 624 with a spark electrode (not shown). The gunpowder 624 generates high-pressure gas by ignition, and the piston 618 moves toward the front side of the vehicle by the pressure. Due to the movement of the piston 618, the plunger head 622 pushes the B.A.BKT 22 with a force exceeding the detachment load by the detachment allowance mechanism 202, and the B.A.BKT 22, that is, the column moving part is moved toward the front of the vehicle. Forced to leave.

  In the present embodiment, as in the first embodiment, the first exhaust port 350 is opened and closed based on whether or not the seat belt is worn, the amount of pull-in of the column 10 (specifically, the column moving portion) is changed, and the driver's Mitigates shock more effectively. Except for the configuration of the column pull-in device 600, for example, the configuration, operation, action, and effect are the same as those in the first embodiment, and thus description thereof is omitted. The column pull-in device 600 is also applicable to the second embodiment.

<Modification>
In each of the above embodiments, only one first exhaust port 350 is provided. However, for example, a plurality of exhaust ports may be provided at equiangular intervals along the circumference. By doing so, the exhaust amount per unit time (exhaust speed) can be increased, and the area of the exhaust port can be reduced.

  In each of the above-described embodiments, the pull-in amount is divided into two stages, but can be made into three or more stages. Further, the pull-in amount can be determined based not only on whether or not the seat belt is worn, but also based on the collision speed, the weight of the driver, and the like.

It is a figure which shows the force added to a driver | operator at the time of a secondary collision. It is a figure which shows the force added to a driver | operator at the time of a secondary collision when a detachment load is almost zero. It is a figure which shows the whole structure of the steering system of 1st Example. It is a side view of the steering column which comprises the steering system of 1st Example. FIG. 4 is a plan view of the steering column shown in FIG. 3. FIG. 4 is a side sectional view of the steering column shown in FIG. 3. FIG. 4 is a perspective view showing a breakaway bracket portion of the steering column shown in FIG. 3. It is a figure which expands and shows the principal part of the 1st EA apparatus in FIG. It is a perspective view which shows the state by which the steering column was attached to the attachment bracket from the vehicle front side. It is sectional drawing which shows the state in which the steering column was attached to the attachment bracket. It is a perspective view which shows the state which decomposed | disassembled the attachment structure of the steering column. It is a figure which shows the attachment state to the attachment bracket of a column drawing-in apparatus. It is side surface partial sectional drawing of the said column drawing-in apparatus. It is a figure which shows the cross section of the rear part of the steering column of 2nd Example. It is a partial cross section figure which shows the attachment state to the attachment bracket of the column drawing-in apparatus of 3rd Example.

Explanation of symbols

10: Steering column 12: Instrument panel reinforcement 14: Column mounting bracket (part of the vehicle body) 20: Column body 22: Breakaway bracket 32: Steering wheel (steering operation member) 34: Airbag device 84: Supported plate (covered) Fastening member) 90: tilt mechanism 92: telescopic mechanism 110: first EA device (impact energy absorbing device) 112: impact energy absorbing plate (deformable member) 150: second EA device (impact energy absorbing device) 172: resin spacer 200: column Support device 202: Release allowing mechanism 300: Column retracting device 302: Cylinder device (actuator) 304: Opening / closing mechanism 350: First exhaust port 360: Shutter ring 362: Solenoid (electromagnetic power source) 400: Steering power The control unit (control device) 404: seat belt sensor [S. S] (Seat belt wearing detector) 406: Displacement sensor (operation member displacement detector) 500: Steering column 520: Retaining ring 522: Compression coil spring 530: Displacement sensor (operation member displacement detector) 600: Column retracting device 608 : Cylinder device (actuator) 610: Opening / closing mechanism

Claims (4)

A steering column for operably holding a steering operation member at one end;
A column support device that includes a disengagement allowance mechanism that allows disengagement of the steering column from a part of the vehicle body with respect to an impact applied to the steering operation member;
A vehicle steering system including a column pull-in device that pulls in the steering column by changing a pull-in amount that is a pull-in amount of the steering column forward of the vehicle;
The column pull-in device is
An actuator serving as a power source for retracting the steering column, comprising a cylinder and a piston that is moved relative to the cylinder by the pressure of the high-pressure gas filled in the cylinder;
An opening / closing mechanism provided in the cylinder for opening and closing an exhaust port for exhausting the high-pressure gas to the outside during the movement of the piston in order to change the pull-in amount of the steering column;
Steering system for a vehicle, characterized in that it comprises a.   2. The vehicle steering system according to claim 1, wherein the column pull-in device changes a pull-in amount of the steering column into a first pull-in amount and a second pull-in amount larger than the first pull-in amount.   The vehicle steering system according to claim 2, wherein the column retracting device is configured to retract the steering column when the seat belt is not worn, and retract the second retracted amount when the seat belt is worn. The steering system detects the displacement of the steering operation member at the time of a secondary collision, and the steering column starts to be retracted based on a detection signal of the operation member displacement detector. The vehicle steering system according to claim 1 , further comprising a control device that controls the column pull-in device.

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