JP4706375B2 - Method and apparatus for measuring limit value of stable region of steering mechanism - Google Patents

Description

  According to the present invention, a lateral force (lateral force) is applied to a wheel of a vehicle, and a stable region of a steering mechanism in which the wheel does not rotate in the lateral force acting direction in a stable posture even under the action of the lateral force. The present invention relates to a method and an apparatus for measuring a limit value in a stable region of a steering mechanism for determining a limit value.

  When the vehicle is traveling on the road surface, a moment is generated in the wheel, and the steering is rotated by the moment. After the steering wheel is rotated and the wheel is also rotated and balanced by the rotation posture of the wheel, the vehicle travels on the road surface in a curved line or in a lateral direction in this state.

  By the way, a plurality of mechanisms are used depending on the vehicle specifications. Generally, a rack and pinion type steering is used for passenger cars and RV cars, and a ball is used for trucks and construction / industrial heavy equipment. Screw type steering is applied. Each mechanism has a manual type and a power type, and what is capable of steering with as little force as possible is so-called power steering.

As a conventional method for evaluating the lateral flow of the vehicle described above, for example, as disclosed in Patent Document 1, the wheel is rotated in a state in which the wheel is placed on the roller and pressed against the roller. The lateral flow of the vehicle is evaluated by measuring the lateral force generated in the vehicle by measuring the amount of axial movement of the roller by rotating the roller in accordance with the rotation, thereby identifying the running characteristics of the vehicle. .
JP 2001-50834 A

  According to the lateral force measuring device and method disclosed in Patent Document 1, it is possible to measure the lateral force acting on the wheel relatively easily. However, such a device / method is stable in the steering mechanism when a lateral force acts on the wheel, that is, when the friction force in the steering mechanism exceeds a certain lateral force, the steering is stable even under the lateral force action. Therefore, the lateral force that causes the lateral flow of the wheels of the vehicle traveling on the actual road surface cannot be accurately identified. In an actual steering mechanism, there is play and frictional force in the mechanism, and with such elements, the steering wheel does not return when the steering is delicately turned. There will be a region that does not affect the drive.

  The present invention has been made in view of the above-described problems, and appropriately considers the frictional force of the steering mechanism, and on the premise of the presence of such frictional force, for example, a stable region where the steering is stable even when the steering wheel is released. It is an object to provide a method and an apparatus for measuring a limit value in a stable region of a steering mechanism that can accurately obtain a lateral force corresponding to a limit value of the vehicle (which is also a limit value at which a lateral flow of a vehicle starts). And

  In order to achieve the above object, the method of measuring the limit value of the stable region of the steering mechanism according to the present invention applies a lateral force synchronized with each of the two wheels of the vehicle whose angle is adjusted by the steering mechanism, A limit value of a stable region of the steering mechanism in which the steering wheel is stable even under the action of the lateral force and the wheels do not rotate in the acting direction of the lateral force is obtained.

  Here, the steering mechanism means a rack and pinion type mechanism, a ball screw type mechanism, and the like, and its constituent members differ depending on the type of the mechanism, and furthermore, the friction force (inherent to the mechanism) existing in the mechanism also increases. It will be different. For example, taking a rack and pinion type power steering mechanism as an example, such a mechanism is composed of a steering column, an enter shaft, a rack and pinion type power steering gear, and the sum of the frictional forces between the respective components is It becomes the frictional force inherent to the mechanism that performs. Further, the stable region of the steering mechanism means that the steering mechanism is stabilized without rotating the wheel even when a certain lateral force is applied, because the frictional force of the steering mechanism is superior to the lateral force acting on the wheel. It is an area that becomes a state.

  In the method of measuring the limit value of the stable region of the steering mechanism of the present invention, for example, by rotating both wheels synchronously in a posture in which the two front wheels of the vehicle are driven, the lateral direction equivalent to the two wheels is obtained. Apply force. Here, the lateral force is a so-called lateral force, and is a force acting in the left-right direction when the direction in which the vehicle goes straight is defined as the front-rear direction. The purpose of this synchronous rotation is to simulate that the same lateral force acts on both wheels simultaneously during normal vehicle rotation or on a cant road surface.

  When the lateral force acting synchronously with the two wheels is gradually increased, the frictional force in the steering mechanism becomes less than a certain lateral force value, and thus the two wheels rotate in the lateral force acting direction. This simulates the lateral flow of the vehicle due to the action of lateral force.

  According to the present invention, a lateral force is applied to the wheel to the left and right, and the limit value of the lateral force in which the vehicle flows laterally in the rotational direction of the wheel is obtained, whereby the frictional force in the steering mechanism inherent to the vehicle is obtained. It is possible to accurately determine the limit value of the stable region of the steering mechanism (the limit value of the lateral flow of the vehicle) that is taken into consideration, which can lead to the specification of the vehicle stability during actual vehicle travel. For example, the slope of the cant road surface is different between Japan and the United States, and the lateral direction of the vehicle is generated by comparing the direction of inclination of each cant road surface and the stable region caused by the friction force inside the target steering mechanism against the slope. When the lateral force to be applied is larger than this stable region, the frictional force inside the target steering mechanism can be adjusted appropriately. Furthermore, considering the friction between the wheel and the road surface, the limit value of the stable region can be obtained by comprehensively judging both the frictional force unique to the steering mechanism and the frictional force between the wheel and the road surface.

  In another embodiment of the method for measuring a stable region of a steering mechanism according to the present invention, two wheels of a vehicle are placed on each of two rotating devices that rotate synchronously, and the vehicle moves forward and backward by the rotation of the wheels. In order to prevent this, the vehicle is positioned and fixed, and the two rotating devices are rotated synchronously in the forward rotation direction and the reverse rotation direction in a posture in which the wheels are rotated. It is characterized by obtaining a limit value.

  For example, it is configured so that two appropriately configured rotating devices can be rotated synchronously, and, for example, two front wheels of the vehicle are placed on each rotating device. Further, the rear wheel is placed on a pedestal of the same level as the turning device, and the vehicle is placed so as to be in a flat posture on the turning device and the pedestal. Here, for example, the front wheels are rotated by driving the front wheels or rotating a rotating drum or the like mounted on the rotating device. The rotating device and the gantry should not be supported by another support member such as a jack so that the entire weight of the vehicle is loaded, but the entire weight of the vehicle should be loaded on the rotating device and the gantry. Thus, the placement state is made to simulate the placement state on the road surface. Since the vehicle moves forward and backward due to the rotation of the front wheels, in order to prevent such movement of the vehicle, the reaction force is applied to the rotating device or the member connected to the gantry or both, so that the vehicle is placed at the mounting place. Try to fix the positioning. For example, it is possible to apply a method in which a long bolt is attached to the rotating device, a bolt hole is formed in the lower surface of the vehicle body, and the long bolt is fitted into the bolt hole and tightened with a nut.

  The rotation device is gradually rotated in a certain direction in a posture in which the vehicle wheel (the front wheel in the above embodiment) is rotated. Note that, at the time of starting the rotation, the wheels are adjusted to the direction in which the vehicle goes straight. Here, the normal rotation direction and the reverse direction mean that the rotation direction is opposite. For example, in a plan view, the normal rotation direction is the clockwise direction, and the reverse direction is the counterclockwise direction.

  By gradually rotating the two rotating devices synchronously in the normal rotation direction, the wheel maintains its original posture without following the rotating device until a certain rotation angle. This is because the lateral force caused by the turning of the turning device is in the stable region caused by the frictional force in the steering mechanism described above. By further increasing the synchronous rotation angle, the lateral force generated on the wheel also increases, and when a certain rotation angle (lateral force) acts on the wheel, the wheel starts to rotate in the rotation direction. By measuring the rotation angle at the start of rotation of the wheel and the lateral force acting on the wheel at the rotation angle, the limit value of the lateral force that causes the experimental vehicle to generate a lateral flow can be obtained.

  After obtaining the lateral force limit value in the forward rotation direction, replace the rotating device and perform the same experiment in the reverse direction. Can be obtained with high accuracy.

  Further, the apparatus for measuring the limit value of the stable region of the steering mechanism according to the present invention applies a lateral force to the wheel of the vehicle, and the steering wheel is in a stable posture even under the action of the lateral force. An apparatus for measuring a limit value of a stable region of a steering mechanism for determining a limit value of a stable region of a steering mechanism that does not rotate in the direction of application of a lateral force, the device mounting two wheels In order to prevent the vehicle from moving forward and backward when the wheels rotate on the rotating device, a rotating device that can rotate while rotating, a pedestal on which two additional wheels constituting the vehicle are mounted, When the two rotating devices are rotated synchronously in the forward rotation direction and the reverse rotation direction in a posture in which the wheel is rotated and the steering mechanism is locked and fixed, the stable region of the steering mechanism in each rotation direction Wherein the measuring means for measuring the lateral force corresponding to the rotational angle of the limit value, to be at least composed.

  The present invention relates to an apparatus for obtaining a lateral force limit value in consideration of a stable region of a steering mechanism. Two of four wheels constituting a vehicle are mounted and synchronously rotated. The rotating device, a pedestal on which the remaining two wheels are placed, and a measuring means for measuring lateral force are roughly configured. This pedestal is configured so that its top end level is substantially the same as the top end level of the rotating device, as in the above-described gantry, and the rotating device and the pedestal are connected to each other. Alternatively, it may be in a separated form. Further, in order to rotate the rotating device in a posture in which the wheel is rotated on the rotating device, for example, the rotating device is provided with a locking means for preventing the vehicle from moving on the rotating device and the pedestal. The form of the locking means is not particularly limited, but can be constituted by a long bolt and a nut as described above. Since the rotation device prevents the vehicle from moving, the rotation device is preferably connected to the laboratory floor or a separate heavy object.

  For example, the rotation device is rotated in the normal rotation direction and the reverse direction in a posture in which the front wheel of the vehicle is rotated, and the rotation angle at which the wheel starts to rotate in both rotation directions, and acts on the wheel at that time. By measuring the lateral force, the lateral force limit value at which the vehicle flows laterally can be obtained.

  Furthermore, in another embodiment of the device for measuring the limit value of the stable region of the steering mechanism according to the present invention, the turning device is mounted on the first support base and the first support base in a freely rotatable manner. It comprises at least a pivot shaft and a second support base pivotally supported by the pivot shaft. The second support base is wound with two large rollers and a space between the two large rollers. And a plurality of small rollers for maintaining the flatness of the belt when a wheel is placed on the belt.

  The present invention relates to an embodiment of a turning device among components of a device for measuring a limit value of a stable region of a steering mechanism. The first support base is a base that supports the rotating device on the floor surface, and a rotary shaft extending in a vertical direction is rotatably attached to the support base, and a second shaft is attached to an upper end portion of the rotary shaft. A support base is fixed. Here, the second support base is composed of, for example, a housing whose upper side is opened, and two large rollers (relatively larger rollers than the small rollers described later) are spaced apart from each other in the housing. It is pivotally supported so that it can rotate. A belt is wound between both large rollers, and a wheel is placed on the upper surface of the belt. As this belt, for example, a metal belt can be used. In addition, when a wheel is placed on a belt that is stretched between two large rollers, a plurality of small rollers rotate between the two large rollers so that the belt does not fall downward due to the weight of the vehicle. It is pivotally supported so as to support the belt between the large rollers from below. Both rotating shafts that rotate synchronously can be rotated by, for example, a servo motor. A rotary encoder can be attached to this servo motor, and both rotation speeds and rotation angles can be accurately synchronized via the interface circuit.

  The rotation device of the present embodiment has a very simple configuration, and the manufacturing cost thereof is relatively low. As a result, the manufacturing cost of an inexpensive stable region measuring device is led.

  As can be understood from the above description, according to the method and the apparatus for measuring the limit value of the stable region of the steering mechanism of the present invention, the stable region (acting on the wheel) caused by the frictional force inherent to the steering mechanism used. In consideration of the frictional force region greater than the lateral force, it is possible to accurately determine the limit value at which the vehicle discloses the lateral flow during actual vehicle travel. Such lateral flow is caused by the inclination of the cant road surface. For example, since the inclination direction is different in Japan and the United States, the road surface cant situation in the country used and the specifications of the steering mechanism applied to the vehicle By calculating the lateral flow limit value according to the above, a vehicle that is difficult to laterally flow on an arbitrary cant road surface can be manufactured by adjusting the frictional force inside the steering mechanism based on the result.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a situation in which a vehicle is mounted on the measuring device of the present invention and a stable region of the steering mechanism is measured, and FIG. 2 is a lateral force acting on the vehicle on a cant road surface. It is the figure which showed the friction force typically. FIG. 3 shows a graph showing the stable region of the steering mechanism, and FIG. 4 shows a diagram showing that the lateral force deviates from the stable region of the steering mechanism. Of course, the measuring device is not limited to the illustrated embodiment.

  In FIG. 1, the front wheels of the vehicle A are placed on the rotating devices 1 and 1 constituting the measuring device for determining the limit value of the stable region of the steering mechanism, and the rear wheels are placed on the base 6. It shows the state. The rotation device 1 includes a support base 3 for placing the rotation device 1 on a floor surface, a rotation shaft 4 extending in a vertical direction supported rotatably on the support base 3, and the rotation The housing 2 fixed to the upper end of the shaft 4, supports 21, 21,... Supporting the housing 2 other than the rotating shaft 4, two large rollers 51, 51 provided in the housing 2, The metal belt 53 wound between the large rollers 51, 51, and a plurality of small rollers 52, 52,... For ensuring the flatness of the metal belt 53 with respect to the weight of the vehicle A. Has been. Here, the supports 21, 21,... Are members for stably supporting the casing 2, and only support the lower surface of the casing 2 in the form of a rim. It will not be a hindrance. In order to prevent the vehicle from moving forward and backward due to the rotation of the front wheels, a long bolt 7 protruding from the support base 3 is fitted into a bolt hole at the lower part of the vehicle body (not shown), and tightened with a nut. The rotating devices 1 and 1 that rotate in a posture in which each front wheel is placed are connected to and controlled by an interface circuit (not shown) so that they can rotate synchronously. Further, the rotation shaft 4 is rotated by a servo motor (not shown), and the rotation angle is accurately read by a rotary encoder (not shown) attached to the servo motor, thereby ensuring the accuracy of synchronous rotation.

  In the illustrated embodiment, the front wheels of the vehicle A are rotationally driven, and the large rollers 51, 51, the small rollers 52, 52,... And the metal belt 53 are driven in accordance with the driving of the wheels. In addition, the structure which rotates the metal belt 53 by rotating and driving the large rollers 51 and 51, and drives a front wheel via the frictional force between a metal belt and a wheel may be sufficient. In any configuration, while the front wheels are rotated (simulating the running state of the vehicle), the two rotating devices 1 and 1 are gradually rotated in a certain direction while the vehicle generates a lateral flow. The rotation angle at which the wheel starts to rotate in the rotation direction of the rotation device 1 and the lateral force at that time are measured.

  The synchronous rotation direction of the rotation shafts 4 and 4 is first performed in the X1 direction of FIG. 1, and a lateral flow is generated in the vehicle A in the X1 direction while gradually increasing the rotation angle of the rotation shafts 4 and 4. The rotation angle and the limit lateral force at that time are measured by a measuring means (not shown), and then the rotation shafts 4 and 4 are gradually rotated in the X2 direction to similarly generate a lateral flow in the X2 direction. The angle and the critical lateral force at that time are measured.

  FIG. 2 shows a lateral force F1 acting on the steering mechanism 8, a frictional force F2 inside the steering mechanism, and a frictional force F3 between the wheel and the road surface on a cant road surface in Japan that is inclined to the left with respect to the traveling direction of the vehicle. FIG. In the present invention, among the frictional forces, the above-described device is used to stabilize the steering mechanism 8 caused mainly by the internal frictional force F2 unique to the steering mechanism 8 (the vehicle cant be operated even if a lateral force acts on the wheels). The range that does not flow laterally in the direction of the road surface slope) is to be obtained. Only when a lateral force exceeding a certain range of stability that can resist the lateral force is applied to the vehicle, it is necessary to prevent the lateral flow of the vehicle by opening the steering wheel. It should be noted that in the United States, where the cant road gradient is opposite to that in Japan, the lateral force that causes lateral flow is on the opposite side.

  FIG. 3 shows the lateral force that causes the lateral flow measured in FIG. 1 by calculating the point at which SAT becomes zero from the relationship graph between the self-aligning torque (SAT) and the steering angle (ST) on the cant road surface in Japan. The graph which determines a limit point is shown.

  On road surfaces in Japan that are tilted to the left with respect to the direction of travel of the vehicle, the lateral force limit point (point A) in the right direction must be smaller than that in the left direction (point B). Note that the lateral force (point C) in the graph corresponding to the ST angle coordinate with zero SAT shown in the figure is the residual lateral force. The range (L) from the point A to the point B measured in the experiment is a stable region mainly caused by the frictional force inside the target steering mechanism, and when the acting lateral force enters this graph range. No lateral flow occurs in the vehicle.

  FIG. 4 shows a graph (X-ray) showing the stable region of an arbitrary steering mechanism when the lateral force caused by the cant road surface deviates from the stable region (point P). In such a case, it is possible to easily cope with this by adjusting the frictional force inside the steering mechanism so that the point P is within the stable region of the steering mechanism. For example, the adjustment of the rack and pinion gear. By adjusting the frictional force inside the steering mechanism, the stable region is widened (Y line in the figure), and a steering mechanism can be configured in which no lateral flow of the vehicle occurs on the target cant road surface.

  In addition to the frictional force inside the steering mechanism, the frictional force between the wheel and the road surface can be cited as an element that does not cause a lateral flow against the lateral force. Therefore, an asphalt layer is formed on the surface of the metal belt 53 which is a constituent member of the rotating device 1 shown in FIG. 1, and an experiment is performed in consideration of friction between the asphalt layer and a target wheel (tire). This makes it possible to determine the relationship between the frictional force inside the steering mechanism, the total frictional force consisting of the frictional force between the wheels and the road surface, and the limit lateral force that causes the lateral flow, in addition to adjusting the steering mechanism. By changing the wheel specifications, it is possible to enlarge and adjust the vehicle stable region without causing a lateral flow.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

The schematic diagram which showed the condition which mounts a vehicle in the measuring apparatus of this invention and measures the stable area | region of the steering mechanism of a steering mechanism. The figure which showed typically the lateral force and frictional force which act on a vehicle on a cant road surface. A graph showing a stable region of the steering mechanism. The figure which showed that lateral force has deviated from the stable area | region of a steering mechanism.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Turning apparatus, 2 ... Housing | casing, 3 ... Support stand, 4 ... Turning axis, 51 ... Large roller, 52 ... Small roller, 53 ... Belt, 6 ... Base, 7 ... Long bolt, 8 ... Steering mechanism , A ... Vehicle

Claims (4)

Two wheels of a vehicle whose angle is adjusted by a steering mechanism are rotated, a lateral force synchronized with each of the wheels is applied , and the steering is in a stable posture even under the action of the lateral force. A method for measuring a limit value of a stable region of a steering mechanism, wherein a limit value of a stable region of a steering mechanism that does not rotate in the direction of application of a lateral force is obtained.   An attitude in which the two wheels of the vehicle are mounted on each of the two rotating devices that rotate synchronously, and the vehicle is positioned and fixed to prevent the vehicle from moving forward and backward due to the rotation of the wheels, and the wheels are rotated. The stability of the steering mechanism according to claim 1, wherein the two rotation devices are rotated synchronously in the normal rotation direction and the reverse rotation direction, respectively, and the limit value of the stable region of the steering mechanism in each rotation direction is obtained. A method of measuring the limits of a region. The limit value of the stable region of the steering mechanism in which a lateral force is applied to the wheel of the vehicle, the steering is in a stable posture even when the lateral force is applied, and the wheel does not rotate in the direction of the lateral force. A device for measuring a limit value of a stable region of a steering mechanism for obtaining
The apparatus includes a rotating device that can rotate synchronously while placing two wheels, a pedestal on which two additional wheels constituting the vehicle are placed, and a vehicle when the wheels rotate on the rotating device. To prevent the vehicle from moving forward and backward, and when the two rotating devices are rotated synchronously in the normal rotation direction and the reverse direction, respectively, in the posture of rotating the wheel, And a measuring means for measuring a lateral force corresponding to a rotation angle that is a limit value of a stable region of the steering mechanism in the rotation direction of the steering mechanism, and a limit value of the stable region of the steering mechanism, characterized in that Measuring device.   The rotating device includes at least a first support base, a rotary shaft rotatably mounted on the first support base, and a second support base pivotally supported on the rotary shaft. The second support base has two large rollers, a belt wound between the two large rollers, and maintains the flatness of the belt when a wheel is placed on the belt. The apparatus for measuring the limit value of the stable region of the steering mechanism according to claim 3, comprising: a plurality of small rollers.

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