JP2015101112A - Wheel support device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce load acting on a cabin C from front wheels 10 at small overlap collision.SOLUTION: A base end of a tie rod 40 and a tip end of a rack bar 51 are connected to each other by a ball joint 60. A stopper 41 which abuts on a socket open end 67 of the ball joint 60 is formed at the base end of the tie rod 40. When an oscillation angle θ of the tie rod reaches a release set oscillation angle θmax2 which is set at an angle becoming larger than a normal-time maximum oscillation angle θmax1, and smaller than a collision-time oscillation angle θcrash, the stopper 41 abuts on the socket open end 67, and a ball 62 is withdrawn from a socket 61. By this constitution, connection between the tie rod 40 and the rack bar 51 is released, and the front wheels 10 largely outwardly rotate, and are pushed out to both sides outside a vehicle.

Description

  The present invention relates to a wheel support device that supports a front wheel in a steerable manner.

  2. Description of the Related Art Conventionally, a technique for dispersing a collision load input from the front of a vehicle body to vehicle body members using the behavior of front wheels is known. For example, Patent Document 1 proposes a technique for dispersing a collision load from a front wheel to a vehicle body member by causing the front wheel to move backward while causing it to interfere with a vehicle body member by a collision load input from the front of the vehicle.

Japanese Patent Laid-Open No. 2004-9893

  In the case of a small overlap collision that collides with the barrier from the front at the width direction end of the vehicle, the load acting on the cabin from the front wheel can be reduced by turning the front wheel largely outward. However, depending on the type of steering, the front wheels cannot be rotated well in a small overlap collision. The reason will be described below. FIG. 6 is a diagram schematically illustrating the movement of the front wheels at the time of a small overlap collision. The front wheel FW is rotatably supported by a knuckle N attached to the suspension arm SA. The tip of the tie rod TR is connected to the knuckle N. The base end of the tie rod TR is connected to the rack bar RB, and swings by the axial movement of the rack bar RB to steer the front wheel FW.

  During a small overlap collision, the front wheel FW is pushed rearward by the barrier B. Thereby, the front wheel FW begins to turn outward. Although the load acting on the cabin can be reduced if the front wheel turns to the outside as it is, the tie rod TR is connected to the knuckle N on the front side of the vehicle with respect to the kingpin shaft of the front wheel FW as shown in FIG. In this type of vehicle, the front wheel FW is pushed rearward while being pulled by the tie rod TR. Therefore, the front wheel is recessed toward the cabin C without being largely turned outward. For this reason, the load acting on the cabin C cannot be reduced well.

  On the other hand, in a vehicle in which the tie rod TR is connected to the knuckle N on the rear side of the vehicle relative to the kingpin shaft of the front wheel FW, the swing direction of the tie rod TR due to the outer rotation of the front wheel FW and the front wheel FW Since the swinging direction of the tie rod TR due to the backward movement is reversed, the swinging amount of the tie rod TR is small as a result. Further, even if the tie rod TR pulls the front wheel FW, the force acts to rotate the front wheel FW. For this reason, the tie rod TR does not disturb the abduction of the front wheel FW.

  An object of the present invention is to cope with the above-described problem. In a wheel support device in which a tie rod is connected to a knuckle on the front side of a vehicle with respect to a kingpin shaft, a load acting on a cabin from a front wheel at the time of a small overlap collision. It is to reduce.

In order to achieve the above object, the present invention is characterized by a knuckle (20) that rotatably supports a front wheel (10) with respect to a vehicle body, and a tip connected to the knuckle on the vehicle front side of the kingpin shaft, A wheel support device including a tie rod (40) connected to a rack bar (51) provided at a base end of the steering device;
The tie rod and the rack bar include a socket (61) provided at a tip of the rack bar and a ball (62) provided at a base end of the tie rod and housed in the socket as constituent elements. Connected by a joint (60),
The tie rod is provided with a stopper (41) that limits a range in which the tie rod can swing with respect to the socket by contact with the socket in the vicinity of a portion where the ball is provided.
The maximum swing angle that the tie rod can swing that is limited by the stopper is larger than the swing angle (θmax1) of the tie rod that corresponds to the maximum steering angle of the front wheel that is limited by the steering device. A preset swing angle (θmax2) set in advance as a swing angle for releasing the front wheel from the steering device;
When a force to swing the tie rod larger than the set swing angle is exerted by a force input to the front wheel from the outside, the ball is removed from the socket by the contact between the stopper and the socket. It is configured to be detached or to break the tie rod.

  In the present invention, the tip of the tie rod is connected to the knuckle on the vehicle front side of the kingpin shaft, and the base end of the tie rod is connected to the rack bar. The tie rod and the rack bar are connected by a ball joint. This ball joint includes a socket provided at the tip of the rack bar and a ball provided at the base end of the tie rod and housed in the socket. Accordingly, when the rack bar moves in the axial direction by the driver's handle operation, the front wheel is steered while the tie rod swings about the ball joint as a fulcrum by this axial movement. The connection between the tie rod and the knuckle does not mean a direct connection, and may be performed, for example, via a knuckle arm provided as a separate part. Moreover, it is good to interpose a ball joint etc. in a connection part.

  The tie rod is provided with a stopper in the vicinity of a portion where the ball is provided. This stopper limits the range in which the tie rod can swing with respect to the socket by contacting the socket provided at the tip of the rack bar. For example, the stopper is formed to protrude radially outward from the side surface of the tie rod. The maximum steering angle of the front wheels is limited by the steering device, but the maximum swing angle of the tie rod that can be swung limited by this stopper is greater than the swing angle of the tie rod corresponding to the maximum rudder angle limited by the steering device. The set swing angle is set in advance as the swing angle at which the front wheel is released (separated) from the steering device in the event of a vehicle collision. The swing angle of the tie rod represents the swing angle of the tie rod with respect to the socket.

  When the vehicle collides with a small overlap, the front wheels rotate while being pushed rearward by the collision load. Along with this, the swing angle of the tie rod increases. When the swing angle reaches the set swing angle, the stopper comes into contact with the socket. When a force for swinging the tie rod larger than the set swing angle is applied, the tie rod swings with the contact point between the stopper and the socket as a fulcrum. As a result, the ball is pulled out (detached) from the socket, or bending stress concentrates on the proximal end of the tie rod and the tie rod is broken. As a result, the connection between the tie rod and the rack bar is released, and the front wheels are released from the steering device and largely abducted. Therefore, according to this invention, the load which acts on a cabin from a front wheel can be reduced.

  In the above description, in order to help the understanding of the invention, the reference numerals used in the embodiments are attached to the configuration of the invention corresponding to the embodiment in parentheses, but each constituent element of the invention is the reference numeral. It is not limited to the embodiment defined by.

It is a partial sectional view showing the connection structure of a tie rod and a rack bar. It is explanatory drawing showing normal time maximum rocking angle thetamax1. It is explanatory drawing showing detachment setting rocking angle thetamax2. It is operation | movement explanatory drawing when a tie rod remove | deviates from a rack bar. It is the figure which represented typically the motion of the front wheel at the time of the small overlap collision which concerns on this embodiment. It is the figure which represented typically the motion of the front wheel at the time of the small overlap collision which concerns on a prior art example.

  Hereinafter, a wheel support device according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 5, the wheel support device includes a knuckle 20 that rotatably supports the front wheel 10, a suspension arm 30 that rotatably supports the knuckle 20 with respect to the vehicle body 100, and a front wheel 10 that is connected to the knuckle 20. And a tie rod 40 for steering. The knuckle 20 rotatably supports the axle hub by a ball bearing (not shown). The front wheel 10 is fixed to the axle hub. Thereby, the knuckle 20 supports the front wheel 10 rotatably.

  The suspension arm 30 is a lower arm formed in a substantially V shape, and includes vehicle body side connection portions 31 and 32 at positions corresponding to both ends of the V shape, and a wheel side connection portion 33 at a position corresponding to the central vertex of the V shape. It has. The vehicle body side connection portions 31 and 32 are connected to the vehicle body 100 (suspension member) via bushes 31b and 32b, respectively. The vehicle body front connecting portion 31 is connected to the vehicle front side with respect to the vehicle body side connecting portion 32. Further, the wheel side connecting portion 33 is provided so as to project outward from the vehicle body 100 in the vehicle width direction, and is connected to the knuckle 20 at a position almost directly below the axle bubbling via the ball joint 21. Therefore, the front wheel 10 is supported by the suspension arm 30 so as to be swingable and turnable with respect to the vehicle body 100.

  The proximal end of the tie rod 40 is connected to the distal end of a rack bar 51 provided in the steering gear box 50 via a ball joint 60. Further, the tip of the tie rod 40 is connected via the knuckle 20 and the ball joint 22. Each of the ball joints 21 and 22 is provided such that the connecting shaft is directed substantially in the vertical direction.

  The vehicle provided with the wheel support device of the present embodiment is a rear wheel drive vehicle in which a steering gear box 50 is provided on the front side of the vehicle, and the connection position between the tie rod 40 and the knuckle 20 is determined between the suspension arm 30 and the knuckle 20. It is on the vehicle front side from the connection position. For this reason, the tie rod 40 is connected to the knuckle 20 on the vehicle front side with respect to the kingpin shaft (the steered shaft of the front wheels).

  The main body of the rack bar 51 is disposed in the steering gear box 50 and both left and right ends (both ends in the vehicle width direction) are exposed from the steering gear box 50. The steering gear box 50 includes a rack and pinion mechanism therein, and converts the rotational movement of the steering shaft rotated by the steering handle into the advancing and retreating operation of the rack bar 51 in the vehicle width direction by the rack and pinion mechanism.

  As shown in FIG. 1, a metal socket 61 that is a component of the ball joint 60 is fixed to the tip of the rack bar 51. The socket 61 includes a ball storage seat 63 that stores the ball 62, and a fastening bolt 64 that is integrally provided on the base end side of the ball storage seat 63. The socket 61 is fastened to the front end of the rack bar 51 by screwing a fastening bolt 64 with a screw hole 52 provided at the front end of the rack bar 51.

  The ball storage seat 63 stores a metal spherical ball 62 via a resin sheet 65. The ball 62 forms a component of the ball joint 60 that forms a pair with the socket 61, and is provided at the proximal end of the tie rod 40. As shown in FIG. 2, the ball 62 and the tie rod 40 are integrally formed in such an arrangement that the central axis L2 of the tie rod 40 passes through the center O of the ball. A circular opening 66 is formed at the front end side of the ball storage seat 63, and a connecting portion between the ball 62 and the tie rod 40 is exposed from the opening 66. In the socket 61, the socket central axis L1 that connects the center of the opening 66 and the center of the ball storage seat 63 (that is, the central axis that connects the center of the opening 66 and the center O of the ball 62) is the center of the rack bar 51. It is fixed to the tip of the rack bar 51 so as to be arranged coaxially with the shaft (referred to as a rack shaft). The socket 61 may be fixed to the tip of the rack bar 51 so that the socket center axis L1 forms a predetermined angle that is not coaxial with the rack axis.

  The socket 61 supports the tie rod 40 in a swingable manner in a state where the ball 62 is stored in the ball storage seat 63. The connecting portion between the tie rod 40 and the rack bar 51 is covered with a bellows-like boot 70.

  Since both ends of the tie rod 40 are connected to the rack bar 51 and the knuckle 20 as described above, when the rack bar 51 moves back and forth in the rack axis direction by a handle operation, the front wheel 10 is rotated while swinging accordingly. Rudder. Hereinafter, the swing angle of the tie rod 40 with respect to the socket 61, that is, the angle formed by the center axis L2 of the tie rod 40 and the socket center axis L1 is referred to as a tie rod swing angle θ.

  A stopper 41 protruding in a ring shape toward the radially outer side is integrally formed at the base end of the tie rod 40. When the tie rod 40 swings with the center O of the ball 62 (the center of the ball storage seat 63) as a fulcrum, the stopper 41 has an end 67 (on the opening portion 66 of the socket 61 on the extension line in the swing direction of the stopper 41). Hereinafter, it is positioned so that the socket open end 67) is arranged.

  The rudder angle range (maximum rudder angle) of the front wheels 10 that can be steered by the driver is set by the forward / backward stroke range of the rack bar 51. For example, the left and right maximum advance / retreat positions (stroke ends) of the rack bar 51 are set by a rack end member (not shown) provided in the steering gear box 50, thereby determining the steering angle range of the front wheels 10. In a normal use state, the front wheels 10 are steered in this steering angle range. The tie rod swing angle θ when the front wheel 10 is at the maximum outward steering angle is referred to as a normal maximum swing angle θmax1.

  As shown in FIG. 2, the stopper 41 is in a state where the tie rod swing angle θ is the maximum swing angle θmax1 in the normal state, that is, in a state where the front wheel 10 is steered outward to the maximum steering angle by the steering handle. As shown in FIG. 3, the protruding length in the radial direction so as to contact the socket open end 67 at a position where the tie rod swing angle θ becomes the separation set swing angle θmax2 as shown in FIG. Is set.

  The inventors of the present application performed various small overlap collision tests, and measured the maximum swing angle of the tie rod 40 (referred to as a swing angle θcrash during a collision) at the time of the small overlap collision. The collision swing angle θcrash is larger than the normal maximum swing angle θmax1. As described above, if the movement of the front wheel 10 is constrained by the tie rod 40 at the time of the small overlap collision, the front wheel 10 cannot be largely rotated. Therefore, in the present embodiment, at the time of a small overlap collision, the restraint of the front wheel 10 by the tie rod 40 is released while the front wheel 10 is moving rearward of the vehicle. For this purpose, it is necessary to release the restraint of the front wheel 10 before the swing angle of the tie rod 40 reaches the swing angle θcrash at the time of collision. The collision swing angle θcrash may be a value smaller than the minimum value of the collision swing angle θcrash obtained in a plurality of tests.

  In this embodiment, the stopper 41 is brought into contact with the socket open end 67 by swinging the tie rod 40, whereby the ball 62 is pulled out from the ball storage seat 63 or bending stress is concentrated on the base of the tie rod 40. The tie rod 40 is broken. Thereby, the tie rod 40 is separated from the rack bar 51, and the restraint of the front wheel 10 by the tie rod 40 is released. In order to do so, the detachment set swing angle θmax2, that is, the tie rod swing angle when the stopper 41 abuts against the socket open end 67 is larger than the normal maximum swing angle θmax1, and the swing at the time of collision is It is set to an angle smaller than the moving angle θcrash (θmax1 <θmax2 <θcrash). Accordingly, the stopper 41 does not interfere with the steering operation in a normal time when no vehicle collision occurs, and the stopper 41 can be reliably brought into contact with the socket opening end 67 in the small overlap collision.

  At the time of a small overlap collision, the front wheel 10 is pushed rearward by the barrier B and turned outward. For example, the suspension member 100 that supports the suspension arm 30 may be deformed, or the vehicle body side connection portion 31 or the vehicle body side connection portion 32 of the suspension arm 30 may be removed to change the direction of the suspension arm 30 to the rear. Is directed outward. At this stage, since the front wheel 10 is connected to the rack bar 51 via the tie rod 40, the front wheel 10 moves rearward while being pulled by the tie rod 40. As a result, the tie rod swing angle θ increases.

  When the tie rod swing angle θ reaches the detachment set swing angle θmax2, the stopper 41 comes into contact with the socket open end 67 as shown in FIG. When a load directed from the barrier B to the front wheel 10 is applied to the rear of the vehicle, a force for swinging the tie rod 40 continues to act. As a result, the tie rod 40 swings with the contact point P between the stopper 41 and the socket open end 67 as a fulcrum as shown in FIG. Therefore, the ball 62 is pulled out from the ball storage seat 63. Alternatively, bending stress concentrates on the base of the tie rod 40 and the tie rod 40 breaks.

  Accordingly, the connection between the rack bar 51 and the tie rod 40 is released, and as a result, the front wheel 10 is not restrained by the tie rod 40, that is, is released from the steering device. Thus, as shown in FIG. 5, the front wheel 10 is largely abducted by the load toward the rear of the vehicle. Thereby, the front wheel 10 is prevented from entering the cabin C, and the load acting on the cabin C from the front wheel 10 can be reduced. Further, since the parts around the front wheel 10 are also damaged at the time of the small overlap collision, the front wheel 10 separated from the tie rod 40 is easily pushed outward in the width direction of the vehicle. This also reduces the load acting on the cabin C.

  As described above, according to the wheel support device of the present embodiment, the tie rod swing angle θ is set to an angle larger than the normal maximum swing angle θmax1 and smaller than the collision swing angle θcrash. A stopper 41 is provided at the proximal end of the tie rod 40 when it comes into contact with the socket open end 67 when it reaches the detachment set swing angle θmax2. Thereby, when the vehicle collides with a small overlap, the connection between the rack bar 51 and the tie rod 40 can be released, and the front wheel 10 can be released from the steering device. Accordingly, the load acting on the cabin C from the front wheel 10 can be reduced. Further, since the separation setting swing angle θmax2 is set to be larger than the normal maximum swing angle θmax1, there is no adverse effect on the steering operation of the front wheels 10 at the normal time. Moreover, it can implement by the simple structure that the stopper 41 is provided in the base end of the tie rod 40. FIG.

  As mentioned above, although embodiment which concerns on the wheel support apparatus of this embodiment was described, this invention is not limited to the said embodiment, A various change is possible unless it deviates from the objective of this invention.

  For example, in this embodiment, the socket open end 67 is used as it is as a portion (stopper receiver) that comes into contact with the stopper 41, but the stopper receiver is formed on the socket 61 separately from the socket open end 67. May be. Further, the stopper 41 of the present embodiment is formed in a ring plate shape, but may be any shape as long as it can contact the socket 61, and is not necessarily formed on the entire circumference of the tie rod 40.

  DESCRIPTION OF SYMBOLS 10 ... Front wheel, 20 ... Knuckle, 30 ... Suspension arm, 40 ... Tie rod, 41 ... Stopper, 50 ... Steering gear box, 51 ... Rack bar, 60 ... Ball joint, 61 ... Socket, 62 ... Ball, 63 ... Ball storage seat 67: Socket open end, B: Barrier, C: Cabin, θ: Tie rod rocking angle, θcrash: Rocking angle during collision, θmax1: Maximum rocking angle during normal operation, θmax2: Rocking angle set for separation.

Claims (1)

A knuckle that rotatably supports the front wheel with respect to the vehicle body;
A tie rod having a distal end connected to the knuckle on the vehicle front side of the kingpin shaft and a proximal end connected to a rack bar provided in the steering device;
In a wheel support device comprising:
The tie rod and the rack bar are connected by a ball joint provided as a component with a socket provided at a tip of the rack bar and a ball provided at a base end of the tie rod and housed in the socket;
The tie rod is provided with a stopper in a vicinity of a portion where the ball is provided to limit a range in which the tie rod can swing with respect to the socket by contact with the socket;
The maximum swing angle of the tie rod that can be swung limited by the stopper is larger than the swing angle of the tie rod that corresponds to the maximum steering angle of the front wheel that is limited by the steering device. A preset swing angle set as a swing angle to be released from the steering device,
When a force to swing the tie rod larger than the set swing angle is exerted by a force input to the front wheel from the outside, the ball is removed from the socket by the contact between the stopper and the socket. A wheel support device configured to be detached or to break the tie rod.

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