JP2007283804A - Steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering device capable of suppressing steering of wheels independent of steering operation due to the application of inertia force on a vehicle. <P>SOLUTION: The phase angle between the rotational face P1 of a fork yoke 22 at one end side of an intermediate shaft 14 and the rotational face P2 of a fork yoke 23 at the other end side is adjusted to minimize the steering angle of wheels due to the inertial force loaded on the vehicle. Consequently, even if a cab and a frame are displaced relatively at the time of acceleration/deceleration of the vehicle, the travelling deflection of the vehicle can be prevented or suppressed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a steering apparatus, and more particularly to a steering apparatus suitable for application to a so-called cab-over vehicle.

  Conventionally, vehicles such as trucks and recreational vehicles generally employ a frame structure that facilitates securing the strength of the vehicle body. In such a vehicle, a cab provided with a driver's seat is elastically supported by a cab mount disposed between the frame. As a result, transmission of vibrations from the wheels supported by the frame to the cab is alleviated, and good riding comfort is maintained.

  Even in a vehicle having such a frame structure, the same steering device as that of a vehicle having no frame, such as a monocoque structure that is often used in general passenger cars, is employed (see, for example, Patent Document 1). ).

For example, in a rack and pinion type steering device, one or more intermediate shafts are arranged between a main shaft supported by a steering column and an input shaft on which a pinion connected to the rack is formed. It is configured. The main shaft, intermediate shaft, and input shaft are connected to each other via connecting means such as a universal joint so that changes in the length and angle of each shaft are absorbed. For this reason, the steering operation via the steering wheel is smoothly transmitted by the rotation of each shaft around its own axis and the rotation between the shafts, and is converted into the reciprocating motion of the rack, thereby adjusting the turning angle of the wheels.
Japanese Patent Laying-Open No. 2005-212629

  However, as described above, in a vehicle having a frame structure, since the cab and the frame are elastically connected via the cab mount, they are likely to relatively move due to inertial force during acceleration or deceleration of the vehicle. As a result, even with connecting means such as a universal joint, the steering performance may be affected.

  That is, for example, when braking the vehicle, the frame tends to be displaced rearward by the wheels, but the cab tends to remain in front of the vehicle due to inertial force. As a result, the main shaft on the upper side of the steering device is displaced relatively forward, and the lower input shaft is displaced rearward. For this reason, for example, even if the steering wheel is not moved when the vehicle is traveling straight, the joint portion may be structurally rotated by the relative movement of each shaft. As a result, there is a possibility that the input shaft rotates unintentionally, the wheels are cut, and the traveling of the vehicle is deflected.

  Even in a vehicle having a monocoque structure or other body structure, there may be some play in the structure of the support portion of each shaft, or the body portion may be elastically deformed microscopically. Therefore, it is considered that the above phenomenon is likely to occur particularly in a vehicle having a frame structure, but it is also considered that it can occur to some extent even in a vehicle having another body structure.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a steering device capable of suppressing wheel breakage that is not caused by a steering operation even when an inertial force acts on the vehicle. .

  In order to solve the above-described problems, a steering device according to an aspect of the present invention meshes with a main shaft to which a steering wheel is connected and a first gear portion connected to the wheel, and the first gear portion is rotated by rotation around its own axis. It can be turned to the end of the main shaft opposite to the steering wheel via the input shaft provided with the second gear part to change the turning angle of the wheel by operating and the first joint part provided at one end And an intermediate shaft rotatably connected to an end of the input shaft opposite to the second gear portion via a second joint portion provided at the other end. In this steering device, the steering angle of the steering wheel is constant by adjusting the phase angle, which is the angle formed by the rotation surface of the first joint portion and the rotation surface of the second joint portion of the intermediate shaft. However, the degree to which the wheel turning angle is changed by the inertial force applied to the vehicle is adjusted.

  Here, the “rotation surface of the first joint portion” means a surface along a locus along which the intermediate shaft rotates with respect to the main shaft. Further, the “rotating surface of the second joint portion” means a surface along a trajectory in which the intermediate shaft rotates with respect to the input shaft. Both are virtual surfaces and are expressed to facilitate understanding of the invention.

  The “intermediate shaft” does not have to be one, and a plurality of “intermediate shafts” may be connected. In this case, the phase angle between the first joint portion of the intermediate shaft connected to the main shaft and the second joint portion of the intermediate shaft connected to the input shaft is adjusted.

  According to this aspect, the phase angle, which is the angle formed by the rotation surface of the first joint portion and the rotation surface of the second joint portion, is adjusted, and thereby the wheel breaks due to the inertial force applied to the vehicle. The degree to which the angle changes is adjusted. The inventors have discovered for the first time that the adjustment of the phase angle is effective for adjusting the turning angle of the wheel.

That is, in the past, such a phase angle is generally based on the physical positional relationship including the structure and operation of the joint portion between each joint portion and the joint portion on the opposite side of the main shaft and the joint portion on the input shaft side. It was set. However, it has not been known that when an inertial force is applied to the vehicle with the steering angle of the steering wheel being constant, the phase angle affects the wheel turning angle. The inventors have discovered the effectiveness of adjusting the phase angle by analyzing the mechanism of the connecting portion of each joint portion.
The phase angle is preferably set so as to substantially minimize the wheel turning angle due to inertial force. Note that “substantially” means that the turning angle of the wheel includes a minimum value or an error range in the vicinity thereof.

  In this way, even if the main shaft and the input shaft are relatively displaced due to the inertial force during acceleration / deceleration of the vehicle or the like, the turning angle of the wheel is substantially minimized. Therefore, it is possible to prevent or suppress the vehicle from being deflected due to the wheel being cut off regardless of the steering operation.

  Such a steering device exhibits the effect particularly remarkably when applied to a vehicle having a frame structure in which the cab is elastically supported by a cab mount disposed between the cab and the frame. This is because the relative displacement between the main shaft and the input shaft due to the inertial force acting on the vehicle is large.

  Such a steering device has a configuration in which the first gear portion is a rack that reciprocates in the vehicle width direction, and the second gear portion is a pinion, as will be described later in an embodiment. Is preferred.

  According to the steering device of the present invention, it is possible to suppress wheel breakage that is not caused by a steering operation due to inertial force acting on the vehicle.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is an explanatory diagram illustrating a configuration example of a vehicle to which a steering device according to an embodiment is applied. In addition, although the recreation vehicle which has a frame structure is illustrated in the figure, application of the steering apparatus of this invention is not restricted to this kind of vehicle.

  The vehicle 1 has a frame structure, and a cab 2 provided with a driver's seat is elastically supported by a plurality of cab mounts 4 disposed between the vehicle 1 and the cab 2. Further, the front and rear of the frame 3 are supported by a suspension device including a spring 5 that reduces an impact received from the road surface. Wheels 6 provided on the left and right sides of the vehicle body are rotatably supported by the front and rear suspension devices. A steering device 7 is provided in the vehicle 1 so as to straddle the cab 2 and the frame 3. The detailed configuration of the steering device 7 will be described later.

  Although not explicitly shown in the figure, the frame 3 has a structure including a pair of left and right side members extending in the front-rear direction of the vehicle body and a plurality of cross members that bridge both side members in the vehicle width direction. The cab mount 4 is an elastic member provided with a rubber insulator and has both a support function and a vibration isolation function.

  Due to such a configuration, when the vehicle 1 receives an inertial force in the front-rear direction during acceleration / deceleration or the like, the cab 2 and the frame 3 are likely to be relatively displaced back and forth. For example, when the vehicle is decelerated such as when the vehicle is braked, the frame 3 is attached to the wheel 6 and tends to be displaced rearward as indicated by an arrow A in the figure, but the cab 2 is driven by the inertia force as indicated by an arrow B in the figure. Try to stay ahead. As a result, the steering device 7 is relatively easily displaced back and forth due to the operation of the cab 2 and the frame 3 at the upper and lower portions, respectively.

  Next, the steering apparatus according to the present embodiment will be described in detail. FIG. 2 is an explanatory diagram illustrating a schematic configuration of the steering device.

  The steering device 7 is configured as a so-called rack and pinion type hydraulic power steering. This steering device 7 includes a main shaft 11 to which a steering wheel 10 as a steering member is connected, and an input shaft 13 connected to a power steering gear box (hereinafter referred to as “PS gear box”) 12 supported by the frame 3. , And an intermediate shaft 14 for connecting them.

  The main shaft 11 is connected to the steering wheel 10 at one end side, and is supported in a steering column 15 fixed to the cab 2 so as to be rotatable around its own axis. The other end of the main shaft 11 is connected to one end of the intermediate shaft 14 via a universal joint 16 so as to be rotatable. A U-shaped bifurcated yoke 17 constituting the universal joint 16 is formed at the other end of the main shaft 11.

  One end of the input shaft 13 is formed with a pinion 19 that meshes with the rack 18 in the PS gear box 12, and the other end is rotatable with respect to the other end of the intermediate shaft 14 via the universal joint 20. It is connected. A U-shaped bifurcated yoke 21 constituting the universal joint 20 is formed at the other end of the input shaft 13. In the present embodiment, the rack 18 constitutes the first gear part, and the pinion 19 constitutes the second gear part. When the input shaft 13 is rotated about its own axis by steering the steering wheel 10, the rotational movement of the pinion 19 is converted into the reciprocating movement of the rack 18 in the vehicle width direction, whereby the turning angle of the left and right wheels 6 changes.

  In the steering device 7, hydraulic assistance is performed via a predetermined hydraulic circuit depending on the magnitude of the force applied to the steering wheel 10. A general configuration of the hydraulic power steering is adopted. Therefore, the description is omitted.

  The intermediate shaft 14 is formed with a U-shaped bifurcated yoke 22 constituting a hook joint type universal joint 16 at one end thereof. The bifurcated yoke 22 is connected to the bifurcated yoke 17 of the main shaft 11 through a cross shaft in a state shifted about 90 degrees about its own axis so that the two yokes do not interfere with each other when the yokes are rotated. It has become. On the other hand, a U-shaped bifurcated yoke 23 constituting a hook joint type universal joint 20 is formed at the other end of the intermediate shaft 14. The bifurcated yoke 23 is connected to the bifurcated yoke 21 of the input shaft 13 through a cross shaft in a state shifted about 90 degrees about its own axis so that the two yokes 23 do not interfere with each other when the two yokes rotate. It has become. In the present embodiment, the forked yoke 22 constitutes a first joint part, and the forked yoke 23 constitutes a second joint part.

  That is, the main shaft 11, the intermediate shaft 14 and the input shaft 13 are connected to each other via the universal joints 16 and 20 so as to be rotatable with respect to each other, and changes in the length and angle of each shaft are absorbed. ing. For this reason, the steering operation via the steering wheel 10 is smoothly transmitted by the rotation of each shaft around its own axis and the rotation between the shafts, and is converted into the reciprocating motion of the rack 18. Adjusted.

  FIG. 3 is an explanatory view schematically showing an intermediate shaft. FIG. 4 is an explanatory diagram showing the phase angle formed by the joint portions at both ends of the intermediate shaft. This figure conceptually shows a state in which the intermediate shaft is viewed from its axial direction, that is, from the C direction in FIG.

  As shown in FIG. 3, the intermediate shaft 14 is formed such that a bifurcated yoke 22 provided at one end thereof and a bifurcated yoke 23 provided at the other end thereof are shifted in phase around the axis L thereof. ing. Here, a rotation surface P1 along a trajectory in which the intermediate shaft 14 rotates with respect to the main shaft 11, and a rotation surface along a trajectory in which the intermediate shaft 14 rotates with respect to the input shaft 13. A description will be given by virtually considering P2. In addition, this rotation surface P1 is a surface perpendicular | vertical to the arrangement | positioning surface P3 in which a pair of arm 31 which comprises the U-shaped bifurcated yoke 22 is arrange | positioned. Similarly, the rotation surface P2 is a surface perpendicular to the arrangement surface P4 on which the pair of arms 32 constituting the U-shaped bifurcated yoke 23 is disposed.

  As shown in FIG. 4, an angle formed by the rotation surfaces P1 and P2 is a phase angle θ. Here, when viewed from the direction C in FIG. 3, the phase in which the rotation surface P1 is shifted clockwise around the axis L with respect to the rotation surface P2 is considered positive, and the phase shifted in the counterclockwise direction is considered as negative. . In the present embodiment, the phase angle θ is adjusted so that the wheels 6 can be prevented from being cut off due to the influence of inertial force such as during acceleration / deceleration of the vehicle 1.

  FIG. 5 is an explanatory diagram illustrating an analysis example of the relationship between the phase angle of the joint portion and the turning angle of the wheel. In the figure, the horizontal axis represents the phase angle θ, and the vertical axis represents the wheel turning angle α. As described above, the phase angle θ is based on the phase of the bifurcated yoke 23 on the input shaft 13 side of the intermediate shaft 14. The phase shifted from the state in which the bifurcated yoke 22 on the main shaft 11 side overlaps the bifurcated yoke 23 is positive, and the phase shifted counterclockwise is negative. The solid line in the figure represents the analysis result when the vehicle 1 is set to the right-hand drive vehicle, and the alternate long and short dash line in the figure represents the analysis result when the vehicle 1 is set to the left-hand drive vehicle.

  That is, the inventors statically applied a phase angle θ to both bifurcated yokes of the intermediate shaft 14 in a state where the steering wheel 10 of a certain vehicle 1 is kept in a straight traveling state, thereby braking the vehicle 1. The cutting angle α of the wheel 6 was analyzed using the phase angle θ as a parameter.

  According to the figure, in a right-hand drive vehicle, when the phase angle θ is 13 degrees clockwise and 77 degrees counterclockwise, the turning angle α of the wheel 6 is minimized, and in the left-hand drive vehicle, the phase angle θ It can be seen that the turning angle α of the wheel 6 is minimized when is 10 degrees clockwise and 73 degrees counterclockwise. Thereby, it was confirmed that the phase angle θ affects the turning angle of the wheel 6. It was also found that the turning angle of the wheel 6 can be suppressed by setting the phase angle θ to a predetermined angle.

  Therefore, in the present embodiment, even when the phase angle θ is selected so that the turning angle of the wheel 6 is minimized and the inertial force during braking acts, the traveling of the vehicle 1 is not deflected unexpectedly. To do. However, when the setting of the phase angle θ also affects other functions of the steering device 7, an appropriate phase angle θ is set so that the turning angle of the wheel 6 is as small as possible based on the analysis result shown in the figure. Like that.

  Although the analysis result at the time of braking of the vehicle 1 is shown in the figure, it is assumed that the optimum value of the phase angle θ changes depending on the magnitude of the acceleration / deceleration of the vehicle 1 or the like. In that case, the phase angle θ may be selected so that the cutting angle of the wheel 6 is minimized in such a situation in consideration of the situation where the cutting of the wheel 6 of the vehicle 1 is to be most suppressed. .

  As described above, in the present embodiment, the angle formed by the rotation surface P1 of the bifurcated yoke 22 on one end side of the intermediate shaft 14 and the rotation surface P2 of the bifurcated yoke 23 on the other end side. A certain phase angle θ is adjusted so that the turning angle of the wheel 6 due to the inertial force applied to the vehicle is minimized. As a result, even when the cab 2 and the frame 3 are relatively displaced during acceleration / deceleration of the vehicle, it is possible to prevent or suppress the vehicle from being deflected.

  The present invention is not limited to the above-described embodiments, and various modifications such as design changes can be added to the embodiments based on the knowledge of those skilled in the art. The described embodiments can also be included in the scope of the present invention.

  For example, in the above embodiment, the angle formed by the rotation surface of the bifurcated yoke 22 on one end side of the intermediate shaft 14 and the rotation surface of the bifurcated yoke 23 on the other end side is set as the phase angle θ. Indicated. In the modification, an angle formed by the arrangement surface P3 on which the pair of arms 31 of the bifurcated yoke 22 is arranged and the arrangement surface P4 on which the pair of arms 32 of the bifurcated yoke 23 is arranged is set as a phase angle. You may set the optimal value which can suppress a cutting angle. Although the embodiment and the modified example are the same as a result, it is considered that it is more convenient to use the rotation surface as a reference when the shape of the yoke is not a bifurcated yoke.

  In the above embodiment, an example in which one intermediate shaft 14 is interposed between the main shaft 11 and the input shaft 13 has been described. However, a plurality of intermediate shafts are interposed. It may be. In that case, the phase angle between the first joint portion of the intermediate shaft connected to the main shaft 11 and the second joint portion of the intermediate shaft connected to the input shaft 13 is adjusted.

  Further, in the above embodiment, an example in which each connecting portion of the main shaft 11 and the input shaft 13 and the intermediate shaft 14 is configured by a hook joint type universal joint is shown. However, a constant velocity joint type universal joint is used. There may be. In addition, other joint structures may be employed as long as the objects to be connected can rotate with respect to each other.

  Furthermore, although the rack and pinion type steering device has been described in the above embodiment, other types such as a ball and nut type may be used as long as they have the joint structure described above.

  Further, in the above-described embodiment, an example in which the steering device 7 is configured by hydraulic power steering has been described, but it may be configured by electric power steering.

  Further, in the above-described embodiment, an example in which the present invention is applied to a vehicle having a frame structure in which the effect is noticeable is shown. However, application to a vehicle having a monocoque structure or other body structures is not hindered.

It is explanatory drawing showing the structural example of the vehicle to which the steering device which concerns on embodiment was applied. It is explanatory drawing showing schematic structure of a steering device. It is explanatory drawing which represented the intermediate shaft typically. It is explanatory drawing showing the phase angle which the joint part of the both ends of an intermediate shaft forms. It is explanatory drawing showing the example of analysis of the relationship between the phase angle of a joint part, and the turning angle of a wheel.

Explanation of symbols

  2 cabs, 3 frames, 4 cab mounts, 6 wheels, 7 steering devices, 10 steering wheels, 11 main shafts, 12 PS gear boxes, 13 input shafts, 14 intermediate shafts, 15 steering columns, 16, 20 universal joints, 17, 21, 22, 23 Forked yoke, 18 racks, 19 pinions, 31, 32 arms P1, P2 rotating surface, P3, P4 arrangement surface

Claims (4)

A main shaft to which a steering member is connected;
An input shaft provided with a second gear portion that meshes with a first gear portion connected to a wheel and operates the first gear portion by rotation around its own axis to change the turning angle of the wheel;
A first joint portion provided at one end is pivotally connected to an end portion of the main shaft opposite to the steering member, and a second joint portion provided at the other end. An intermediate shaft rotatably connected to an end of the input shaft opposite to the second gear portion;
With
The steering angle of the steering member is kept constant by adjusting a phase angle that is an angle formed by the rotation surface of the first joint portion and the rotation surface of the second joint portion of the intermediate shaft. A steering apparatus characterized by adjusting the degree to which the turning angle of the wheel changes due to an inertial force applied to the vehicle.   The steering apparatus according to claim 1, wherein the phase angle is set so as to substantially minimize a turning angle of the wheel due to the inertial force.   The steering apparatus according to claim 1 or 2, wherein the cab is applied to a vehicle having a frame structure elastically supported by a cab mount disposed between the cab and the frame.   The steering apparatus according to any one of claims 1 to 3, wherein the first gear portion is a rack that reciprocates in a vehicle width direction, and the second gear portion is a pinion.

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