Abstract:
An operation input device has an improved position detection accuracy for detecting a position of an operation force by forming a wide portion on one end of an operation unit at a periphery thereof and by fixedly disposing, on a stay, a narrow portion on an opposite end of the operation unit, among which the wide portion protrudes in an in-parallel direction of an operation surface of the operation unit.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    The present application is based on and claims the benefit of priority of Japanese Patent Application No. 2014-075692, filed on Apr. 1, 2014, the disclosure of which is incorporated herein by reference. 
       TECHNICAL FIELD 
       [0002]    The present disclosure generally relates to an operation input device for an input of a controlling operation that controls, for example, a vehicular navigation apparatus, an air conditioning apparatus, or an audio-visual apparatus. 
       BACKGROUND INFORMATION 
       [0003]    A conventional operation input device is an applied force detector which has an operation unit disposed on a shaft, a strain body in a board shape to be elastically deformed according to an applied force that is applied to the operation unit, and at least four strain detection elements for detecting the deformation of the strain body, as disclosed in a patent document 1 (i.e., Japanese Patent Laid-Open No. 2010-181398), for example. Further, the four strain detection elements are disposed on one strain body, that is, on one disposition surface of the body, and the strain body and the shaft of the operation unit are connected by a connection body and have one body. 
         [0004]    The operation input device in the patent document 1 transmits the applied force on the operation unit to the disposition surface that bears the strain detection elements of the strain body via the connection body, and the applied force is detected based on the output signal from the strain detection elements. More practically, the applied force is detected as an x axis operation force along the x axis, a y axis operation force along the y axis, and/or a z axis operation force along the z axis, as well as a moment about the z axis, when the x/y axes are defined as in-parallel axes along an operation surface of the operation unit and the z axis is defined as a perpendicular axis perpendicular to the operation surface. 
         [0005]    However, the device in the patent document 1 is not capable of accurately detecting a position of the operation force when the operation force is a combination of multiple axial forces. That is, depending on the operation of the operation unit by the operator, the applied force may be a combination of an in-parallel force that is in parallel with the operation surface and a perpendicular force that is perpendicular to the operation surface. In such case, the position of the operation force is not accurately detected by the device in the patent document 1. 
       SUMMARY 
       [0006]    It is an object of the present disclosure to provide an operation input device that has an improved accuracy in detecting the position of the operation force. 
         [0007]    For a resolution of the above-described problem, the present disclosure provides the following technical solution. In an aspect of the present disclosure, an operation input device includes an operation unit having an operation surface, a strain body elastically deformed by a force applied to the operation unit, a connection body connecting the operation unit with the strain body, the connection body being at least partially deformed by the force applied to the operation unit, at least four strain gauges respectively gauging a deformation of the strain body, an operation force calculator calculating the force applied to the operation unit based on a gauged strain by each of the at least four strain gauges, and a stay attached to the operation unit. A wide portion of the operation unit is disposed along a periphery of the operation surface and protrudes in a direction that is generally in parallel with the operation surface and a narrow portion of the operation unit is fixedly disposed on the stay. The wide portion is positioned on a side of the operation unit adjacent to the operation surface, and the narrow portion is positioned away from the operation surface on an opposite side of the operation unit relative to the operation surface and the wide portion. 
         [0008]    In another aspect of the present disclosure, the operation unit has a sidewall that narrows from the wide portion toward the narrow portion. 
         [0009]    In yet another aspect of the present disclosure, the connection body is formed from a flat spring. 
         [0010]    In still another aspect of the present disclosure, the operation unit has a cylindrical shape. 
         [0011]    According to the above disclosure, when the operation unit is operated in the in-parallel direction that is in parallel with the operation surface, the wide portion of the operation unit receives the operation force of such operation. In such structure, the narrow portion of the operation unit is fixedly disposed on the stay, a component of the operation force in a perpendicular direction, i.e., a direction from the operation surface toward the narrow portion. Further, a component of the operation force in an opposite direction, i.e., a direction opposite to the one described in the above is also invalidated/canceled (i.e., the component of the operation force in a direction from the narrow portion toward the operation surface). Therefore, the operation force is not a combination (i.e., mixture) of the in-parallel force and the perpendicular force. Thus, the position of the operation force applied to the operation unit in parallel with the operation surface is accurately detected, due to the above structure that cancels the perpendicular force (i.e., a perpendicular force component). 
         [0012]    The numerals in the parentheses represent relationships between the claimed parts of the operation input device in the summary description in the above and the various practical components in the embodiment in the following. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    Objects, features, and advantages of the present disclosure will become more apparent from the following detailed description made with reference to the accompanying drawings, in which: 
           [0014]      FIG. 1  is a block diagram of a navigation apparatus and an operation input device in a first embodiment of the present disclosure; 
           [0015]      FIG. 2A  is a sectional view and a plan view, which shows a connection body, a strain body, and a strain gauge, of the operation input device of the present disclosure; 
           [0016]      FIG. 2B  is a sectional view and a plan view, which shows a connection body, a strain body, and a strain gauge, of the operation input device of the present disclosure; 
           [0017]      FIG. 3A  is a model diagram of a load on a strain body when a z axis force is applied thereon; 
           [0018]      FIG. 3B  is a model diagram of a load on a strain body when a z axis force is applied thereon; 
           [0019]      FIG. 4A  is a model diagram of a load on the strain body when a y axis force is applied thereon; 
           [0020]      FIG. 4B  is a model diagram of a load on the strain body when a y axis force is applied thereon; 
           [0021]      FIG. 5A  is a table diagram of a change of resistance of each of strain bodies that are shown in  FIGS. 3A  and B; 
           [0022]      FIG. 5B  is a schematic diagram of a bridge circuit formed by the strain bodies; 
           [0023]      FIG. 6A  is an illustration of how position coordinates of a perpendicular force are calculated when a perpendicular force is applied to an outer face of an operation panel; 
           [0024]      FIG. 6B  is an illustration of how position coordinates of a perpendicular force are calculated when a perpendicular force is applied to an outer face of an operation panel; 
           [0025]      FIG. 7A  is an illustration of how to detect a force along an x, y, or z axis, and how to detect a moment about the z axis; 
           [0026]      FIG. 7B  is an illustration of how to detect a force along an x, y, or z axis, and how to detect a moment about the z axis; 
           [0027]      FIG. 7C  is an illustration of how to detect a force along an x, y, or z axis, and how to detect a moment about the z axis; 
           [0028]      FIG. 7D  is an illustration of how to detect a force along an x, y, or z axis, and how to detect a moment about the z axis; and 
           [0029]      FIG. 8  is a sectional view of a connection body in a second embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0030]    Embodiments of the present disclosure are described based on the drawings. In each of the embodiments, the same numerals may be borrowed from the preceding embodiment(s), and the description of the same parts may be not repeated. In each of the embodiments, the configuration may be fully described or partially described, in which case a non-described portion of the configuration may be borrowed from the preceding embodiment(s). The combination of the embodiments or parts of the embodiments should be permitted when not only it is explicitly described but also it is only implicitly described, unless otherwise indicated or unless any hindrance factor prevents the combination. 
       First Embodiment 
       [0031]    A configuration of an operation input device  100  in the first embodiment of the present disclosure is described with reference to  FIGS. 1 to 5 . 
         [0032]    As shown in  FIG. 1 , the operation input device  100  is a device which performs an operation input for operating an in-vehicle navigation device  10 , for example. The operation input device  100  may also be used for an input to various apparatuses, e.g., an air-conditioner and audio equipment, other than the above-mentioned navigation device  10 . 
         [0033]    As shown in  FIG. 2 , the operation input device  100  is provided with an operation unit  120 , a connection body  130 , a strain body  140 , a strain gauge  150 , a stay  160 , a signal processor  170  and the like. The connection body  130 , the strain body  140 , and the strain gauge  150  are disposed inside the operation unit  120 . 
         [0034]    The operation unit  120  includes an operation panel  121 , a dial  122 , and a shaft  123 . The operation panel  121  is a circular board shape member. The outer face of the operation panel  121  (i.e., an upper/top face; see  FIG. 2A ) is an operation surface  121   a.  The operation panel  121  is a so-called touch panel for receiving a finger operation (e.g., a touch, a drag, etc.) of an operator/user. 
         [0035]    The operation panel  121  is defined in a coordinate system which uses x, y, z axes for defining position coordinates of a space around the operation input device  100 . That is, a center point of the operation panel  121  is an origin of the coordinate system, with the x axis and y axis extending in parallel with the operation surface  121   a,  and the z axis extends perpendicular to the surface  121   a.  Those axes may also be associated with the vehicle orientation, such as the x axis extending in a right-left direction of the vehicle, with the y axis extending in a front-rear direction and the z axis in a height direction. The operation panel is used for receiving a z axis operation force (i.e., an input of a perpendicular force) at (x, y) position coordinates when the operator&#39;s fingertip touches, drags on or the operation panel  121 . 
         [0036]    The dial  122  is a flat cylindrical member, and is disposed to face an opposite side of the operation surface  121   a  of the operation panel  121 . The dial  122  (i.e., the operation unit  120 ) may be an operation “knob” that is grabbed or pinched with fingers by an operator, and may be pulled, tilted or twisted/rotated along and about each of those axes, for an operation input. One side of the dial  122  facing the operation panel  121  is a shutting surface  122   c  which shuts an opening of the cylinder shape of the dial  122 . At the center of the shutting surface  122   c,  a shaft hole  122   d  is bored. Further, an opposite side of the dial opposite to the shutting surface  122   c  is a narrow portion  122   b,  which is an opening. The edge of the opening of the narrow portion  122   b  is fixed onto the stay  160 . 
         [0037]    The dial  122  has a sidewall  122   e  that has a “negative” slope from one side to the other, i.e., from a shutting surface  122   c  side toward the narrow portion  122   b,  as shown in  FIG. 2A . That is, when the sidewall  122   e  comes close to the narrow portion  122   b,  the diameter of the sidewall  122   e  decreases, which forms an upside-down trapezoid shape cross section. In other words, the sidewall  122   e  of the dial  122  narrows from the wide portion  122   a  to the narrow portion  122   b.  Therefore, the corner of the dial  122  on a shutting surface  122   c  side has an acute angle. The corner may thus be designated as a wide portion  122   a  protruding in an “extending direction” along which the operation surface  121   a  extends. The extending direction may also be called as an in-parallel direction, which is in parallel with the operation surface  121   a.    
         [0038]    The shaft  123  is a rod member which has a substantially circular cross section. One end of the shaft  123  is connected to a center portion surface on a dial  122  side of the operation panel  121 . The shaft  123  is inserted into the shaft hole  122   d  of the dial  122 , and is connected to an inner surface of the shaft hole  122   d.  That is, the operation panel  121 , the dial  122 , and the shaft  123  are integrated to have one united body, to be serving as the operation unit  120 . An opposite end of the shaft  123  opposite to the operation panel  121  extends toward a center portion of an inside space of the dial  122 . 
         [0039]    The connection body  130  connects the operation unit  120  and the strain body  140  mentioned later, and it serves as a connecting member that is at least partially deformed by a force that is applied to the operation unit  120 . The connection body  130  is, as shown in  FIG. 2A , an upside-down U letter shape in its cross section, and is positioned in between the other end of the shaft  123  and the narrow portion  122   b  of the dial  122 . The “bottom” of the U letter shape of the connection body  130  is connected to the shaft  123 . Further, two tops (i.e., edges) of the U letter shape of the connection body  130  are respectively connected to the strain body  140 . 
         [0040]    The strain body  140  which is connected to the connection body  130  is a board shape member of an I letter shape, and is elastically distorted and strained by a force that is applied to the operation unit  120 . The strain body  140  is provided in two pieces, i.e., is formed as a first strain body  140   a,  and a second strain body  140   b.  The two strain bodies  140   a  and  140   b  have the same configuration, extending in parallel with each other along a perpendicular direction that is perpendicular to a virtual plane that includes the U letter shape of the connection body  130 . Both strain bodies  140   a  and  140   b  have a central stationary portion  141 , side ends  142  and  143 , and a gauge holder  144 . 
         [0041]    The central stationary portion  141  is positioned at a center of the I letter shape in the longitudinal direction, and the side ends  142 ,  143  are narrow portions on both ends of the I letter shape. Further, the central stationary portion  141  on each of the strain bodies  140   a,    140   b  is fixed to the tops of the U letter shape. Further, the side ends  142 ,  143  are respectively fixed onto the stay  160 . 
         [0042]    The gauge holder  144  is formed at a position between the central stationary portion  141  and each of the side ends  142  and  143 , and serves as a region where the strain gauge  150  which is mentioned later is positioned. In each of the first and second strain bodies  140   a  and  140   b,  two gauge holders  144  are provided, resulting in four holders  144  in total. As shown in  FIG. 2B , two regions corresponding to two gauge holders  144  of the first strain body  140   a  are hereafter designated as a first region  1401  and a fourth region  1404 . Similarly, two regions corresponding to two gauge holders  144  of the second strain body  140   b  are hereafter designated as a second region  1402  and a third region  1403 . 
         [0043]    The strain gauge  150  is a detector for detecting a distortion or a strain of the strain body  140  which is caused by the distortion of the connection body  130  due to the operation force applied to the operation unit  120 . Four strain gauges  150  are provided respectively in a corresponding manner for each of the four gauge holders  144  on the strain bodies  140   a  and  140   b.  The four strain gauges  150  are designated as a first strain gauge  151 , a second strain gauge  152 , a third strain gauge  153 , and a fourth strain gauge  154 . 
         [0044]    The first strain gauge  151  is positioned in the first region  1401  of the first strain body  140   a.  The second strain gauge  152  is positioned in the second region  1402  of the second strain body  140   b.  The third strain gauge  153  is positioned in the third region  1403  of the second strain body  140   b.  The fourth strain gauge  154  is positioned in the fourth region  1404  of the first strain body  140   a.    
         [0045]    Each of the strain gauges  151  to  154  has four strain gauge elements, respectively, as shown in  FIG. 2B . That is, the first strain gauge  151  has strain gauge elements  151   a,    151   b,    151   c,  and  151   d.  Similarly, the second strain gauge  152  has strain gauge elements  152   a,    152   b,    152   c,  and  152   d.  Similarly, the third strain gauge  153  has strain gauge elements  153   a,    153   b,    153   c,  and  153   d.  Similarly, the fourth strain gauge  154  has strain gauge elements  154   a,    154   b,    154   c,  and  154   d.    
         [0046]    In the present embodiment, as each of the strain gauge elements  151   a - 151   d  and  152   a - 152   d  and  153   a - 153   d  and  154   a - 154   d  of the strain gauges  151  to  154 , the distortion detecting element (i.e., a strain gage) is used, in which the electric resistance value changes according to the distortion of the strain body  140  (i.e., the first and second strain bodies  140   a  and  140   b ), for example. 
         [0047]    In each of the strain gauges  151  to  154 , a bridge circuit as shown in  FIG. 5B  is formed by the four strain gauge elements, i.e., by the elements  151   a - 151   d,    152   a - 152   d,    153   a - 153   d,  and  154   a - 154   d.  The voltage (Vout) of the midpoint of each bridge circuit is output to the signal processor  170 , respectively, which is mentioned later. 
         [0048]    The stay  160  is a base, or a pedestal, for holding the narrow portion  122   b  of the operation unit  120  and each of the strain bodies  140   a,    140   b,  which may be formed by a board shape member. The upper face of the stay  160  on which the strain bodies  140   a/b  are disposed has two grooves  161  that extend along the I letter shape of those bodies  140   a/b.  Further, each of the I letter shape grooves  161  is bridged, or covered, by the I letter shape strain body  140   a  or  140   b.  That is, the side ends  142 ,  143  of the strain body  140   a,  for example, are respectively fixed on the upper face of close-to-end portions of the stay  160 , which are respectively close to both ends of the I letter shape grooves  161 . In other words, the strain bodies  140   a/b  do not contact/touch the stay  160  except for the side ends  142 ,  143 . 
         [0049]    The signal processor  170  is an operative force calculation circuit disposed on the stay  160 . The signal processor  170  calculates the magnitude of the operation force applied to the operation panel  121  and the position of the operation force (i.e., the operation position) based on the output voltage from each of the strain gauges  151  to  154 . The signal processor  170  further calculates the direction (i.e., x, y, z axis directions) and magnitude of the operation force which is applied to the dial  122 , and also calculates the direction and magnitude of a moment of such operation force along a circumference direction about the z-axis. Then, based on the calculation result, the display operation of the navigation device  10  is controlled. For example, a selection of menu icons, and an OK operation for determining the selection, as well as a screen switching between a position display of the own vehicle and a destination guidance on the map, map scrolling are enabled according to the calculation of the position and direction of the operation force. 
         [0050]    Next, the operation of the operation input device  100  constituted as mentioned above is described in detail. 
         [0051]    As shown in FIGS.  3 A/B and FIGS.  4 A/B, operation forces (fz, fy, etc.) are transmitted to the strain body  140  ( 140   a,    140   b ) via the connection body  130  when the operation panel  121  or the dial  122  is operated by an operator. Then, according to the applied force, the strain body  140  is either pulled/expanded or pressed/compressed, and an expansive or compressive deformation is caused therein. As shown in  FIG. 5A , the resistance value of the distortion detecting element increases when the element-having region is pulled or expanded (i.e.,  151   a,    151   b  of FIGS.  3 A/B), or decreases when the element-having region is compressed (i.e.,  151   c,    151   d  of FIGS.  3 A/B,  151   a - 151   d  of FIGS.  4 A/B) Thus, an output voltage value of the bridge circuit changes when the resistance value of each of the strain gauge elements  151   a  to  151   d  changes. 
         [0052]    According to the position, the direction and the magnitude of the operation force applied to the operation panel  121  or the dial  122 , the output voltage values from the strain gauges  151  to  154  differ, respectively. Therefore, the signal processor  170  can recognize the operation force that is applied to the operation panel  121  or the dial  122 , i.e., the position, the direction and the magnitude of the applied operation force, based on the output voltage value in each of the strain gauges  151  to  154 . 
         [0053]    Hereafter, with reference to FIGS.  6 A/B, and  7 A/B/C/D, a method of recognizing the different operation forces from different operations is described. 
         [0054]    1. When the operation force is applied to the operation panel  121  along the z axis 
         [0055]    As shown in FIGS.  6 A/B, when an operation force Fz along the z axis is applied to the operation panel  110  by a touch operation (i.e., a tap) of the operator at position coordinates of x 1 , y 1 , the force along the z axis transmitted to each of the strain gauges  151  to  154  is sensed as fz 1 , fz 2 , fz 3 , and fz 4 , respectively, and the force Fz is thus represented by an equation 1. 
         [0000]        Fz=fz 1+ fz 2+ fz 3+ fz 4   (Equation 1)
 
         [0056]    A moment Fx·x 1  about the y axis by the operation force Fx is represented by an equation 2 when a distance along the x axis from the origin to the strain gauges  151  and  154  and a distance along the x axis from the origin to the strain gauges  152  and  153  are designated as w, respectively. 
         [0000]        Fx·x 1=( fz 1+ fz 4) ·w− ( fz 2+ fz 3) ·w    (Equation 2)
 
         [0057]    A moment Fx·y 1  about the x axis by the operation force Fx is represented by an equation 3 when a moment about the x axis according to the difference between the force fz 1  and the force fz 4  is designated as mz 1 , and a moment about the x axis according to the difference between the force fz 2  and the force fz 3  is designated as mz 2 . 
         [0000]        Fx·y 1= mz 1+ mz 2   (Equation 3)
 
         [0058]    Therefore, based on the equation 1 and the equation 2, an equation 4 is composed. 
         [0000]        x 1={( fz 1+ fz 4)−( fz 2+ fz 3) }·w/ ( fz 1+ fz 2+ fz 3+ fz 4)   (Equation 4)
 
         [0059]    Further, based on the equation 1 and the equation 3, an equation 5 is composed. 
         [0000]        y 1=( mz 1+ mz 2)/( fz 1+ fz 2+ fz 3+ fz 4)   (Equation 5)
 
         [0060]    That is, the position (x, y coordinate positions) of the applied operation force can be grasped based on the forces fz 1  to fz 4  obtained from each of the strain gauges  151  to  154  and the moments mz 1 , mz 2 . 
         [0061]    2. When the operation force is applied to the operation unit  120  along each of x, y, z axes and about the z axis 
         [0062]    (1) The Operation Force Along the x Axis 
         [0063]    As shown in  FIG. 7A , when the operation force Fx along the x axis is applied to the operation unit  120 , a force Fx 1  acts on the central part (i.e., on the central stationary portion  141 ) of the first strain body  140   a  in the minus direction of the z axis. Thereby, the forces fz 1  and fz 4  act on the first strain gauge  151  and the fourth strain gauge  154  in the minus direction of the z axis, respectively. 
         [0064]    Further, a force Fx 2  acts on the central part (i.e., the central stationary portion  141 ) of the second strain body  140   b  in the plus direction of the z axis. Thereby, the forces fz 2  and fz 3  act on the second strain gauge  152  and the third strain gauge  153  in the plus direction of the z axis, respectively. 
         [0065]    (2) The Operation Force Along the y Axis 
         [0066]    As shown in  FIG. 7B , when the operation force Fy along the y axis is applied to the operation unit  120 , a force Fy 1  acts on the central part (i.e., the central stationary portion  141 ) of the first strain body  140   a  in the minus direction of the y axis. Then, due to a moment that is caused by the force Fy 1 , the force fz 1  acts on the first strain gauge  151  in the plus direction of the z axis, and the force fz 4  acts on the fourth strain gauge  154  in the minus direction of the z axis. 
         [0067]    Further, the force Fy 2  acts on the central part (i.e., the central stationary portion  141 ) of the second strain body  140   b  in the minus direction of the y axis. Then, due to a moment that is caused by the force Fy 2 , the force fz 2  acts on the second strain gauge  152  in the plus direction of the z axis, and the force fz 3  acts on the third strain gauge  153  in the minus direction of the z axis. 
         [0068]    (3) The Operation Force Along the z Axis (i.e., a Pull-Up or a Press-Down of the Operation Unit  120 ) 
         [0069]    As shown in  FIG. 7C , when the operation force Fz along the z axis (i.e., in a pull-up direction or in a press-down direction: an example of  FIG. 7C  is a pull-up case) is applied to the operation unit  120 , a force Fz 1  acts on the central part (i.e., the central stationary portion  141 ) of the first strain body  140   a  in the plus direction of the z axis. Thereby, the forces fz 1  and fz 4  act on the first strain gauge  151  and the fourth strain gauge  154  in the plus direction of the z axis, respectively. 
         [0070]    Further, the force Fx 2  acts on the central part (i.e., the central stationary portion  141 ) of the second strain body  140   b  in the plus direction of the z axis. Thereby, the forces fz 2  and fz 3  act on the second strain gauge  152  and the third strain gauge  153  in the plus direction of the z axis, respectively. 
         [0071]    (4) The Operation Force About the y Axis 
         [0072]    As shown in  FIG. 7D , when the operation force Mz about the z axis is applied to the operation unit  120 , a force Mz 1  acts on the central part (i.e., the central stationary portion  141 ) of the first strain body  140   a  in the plus direction of the y axis. Then, due to a moment that is caused by the force Mz 1 , the force fz 1  acts on the first strain gauge  151  in the minus direction of the z axis, and the force fz 4  acts on the fourth strain gauge  154  in the plus direction of the z axis. 
         [0073]    Further, a force Mz 2  acts on the central part (i.e., the central stationary portion  141 ) of the second strain body  140   b  in the minus direction of the y axis. Then, due to a moment that is caused by the force Mz 2 , the force fz 2  acts on the second strain gauge  152  in the plus direction of the z axis, and the force fz 3  acts on the third strain gauge  153  in the minus direction of the z axis. 
         [0074]    Based on the above descriptions ( 1 ) to ( 4 ), the combination of force directions (i.e., plus or minus direction) regarding the forces fz 1  to fz 4  that are generated in each of the strain gauges  151  to  154  is different for each of the operation forces Fx, Fy, Fz, and Mz. Therefore, based on such different combinations of the force directions, the operation of the operation unit  120  is detected and recognized, in terms of which one of the three axes the operation force is oriented, and in terms of whether the operation force about the z axis is caused. 
         [0075]    3. When the operation force is applied to the operation unit  120  in the in-parallel direction that is in parallel with the operation surface  121   a    
         [0076]    When the operation unit  120  (i.e., the dial  122 ) is operated along the operation surface  121   a,  i.e., along the x axis or along the y axis, or along a direction that is arbitrarily composed from x and y axes components, the operation force is mainly received by the wide portion  122   a  of the operation unit  120  (i.e., since the wide portion  122   a  generally defines an outline of the operation unit  120  at the position close to the operation panel  121 ). 
         [0077]    When the operation force is received as the in-parallel operation force by the wide portion  122   a,  such an operation force is sensed as a force in/along the x-y plane which includes no perpendicular force component, because the narrow portion  122   b  of the operation unit  120  is fixed on the stay  160 . That is, the fixation of the narrow portion  122   b  on the stay  160  cancels a force component along a perpendicular direction, which may be a direction from the operation surface  121   a  toward the narrow portion  122   b,  or a direction from the narrow portion  122   b  toward the operation surface  121   a.  Such a force component may also be designated as a force in the plus direction of the z axis, or a force in the minus direction of the z axis. 
         [0078]    That is, in other words, a generally in-parallel operation force is isolated to be a purely in-parallel operation force, due to the structure of the operation unit  120  described above, which eliminates the z axis operation force components, either in the positive direction or in the negative directions. Therefore, the combination of the in-parallel force and the perpendicular force, or the corruption of the in-parallel force by the perpendicular force, is prevented. Therefore, an accurate operation position of the operation force is detected. 
       Second Embodiment 
       [0079]    An operation input device  100 A of the second embodiment is shown in  FIG. 8 . In the present embodiment, the shape of the connection body  130  is changed from the one in the above-described first embodiment, to make a connection body  130 A. 
         [0080]    The connection body  130 A is formed with a single flat spring that is bent two or more times. The flat spring may be formed, for example, by a press work. A part of the connection body  130 A is formed as a thin board shape. The number of the bending of the body  130 A as well as the x/y axis dimension of the flat spring and the height of the after-bending flat spring along the z axis are respectively predetermined together with other conditions. 
         [0081]    The connection body  130 A provides, other than a holding function that fixedly holds the operation unit  120 , and the strain body  140 , an operation force transmitting function that transmits, to the strain body  140 , the operation force applied to the operation unit  120 . 
         [0082]    In particular, the moment about the z axis may be transmitted in an amplified manner to the strain body  140  when a part of the connection body  130 A is made thinner. That is, the amount of deformation of the strain body  140  for the same twisting moment may be increased in such manner. 
         [0083]    By providing the connection body  130 A as the flat spring, the connection body  130 A serves as a connection body as well as serving as an elastic body. By having an elastic body, the operation unit  120  may be more easily moved/displaced by the operation force, thereby making it easier for the operation unit  120  to detect the operation force from the operator. 
         [0084]    Further, by folding/bending the flat spring in many times, i.e., by the adjustment of the number of foldings and the dimensions of the folded portions, the displacement (i.e., move) of the operation unit  120  by the x axis force and the displacement of the same unit  120  by the y axis force may be substantially equated. That is, a natural and nonbiased operation feeling of the operation unit  120  may be realized in such manner. 
       Other Embodiments 
       [0085]    Although the present disclosure has been fully described in connection with preferred embodiment thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications become apparent to those skilled in the art. 
         [0086]    For example, the negative slope of the operation unit  120 , i.e., the sidewall  122   e  of the dial  122  is negatively inclined to form the wide portion  122   a,  in the above embodiment may be changed to a different form. That is, the dial  122  may be made as a straight cylinder, having a constant diameter cross section, and only a narrow portion of the dial  122  close to the operation panel  121  may be made to protrude along the operation panel  121  as a wide portion. In other words, the sidewall  122   e  of the dial  122  narrows from the wide portion  122   a  to the narrow portion  122   b.    
         [0087]    Although the strain body  140  may be formed as two separate parts  140   a  and  140   b  respectively having the I letter shape in the above, the strain body  140  may be made in one body, i.e., as a press work of one board for having an O letter shape. Further, the four strain gauges  151  to  154  may be formed in one body, i.e., as one strain body on one board. Alternatively, the four gauges  151  to  154  may be separately disposed on respectively different four strain bodies. 
         [0088]    Further, the operation surface  121   a  of the operation panel  121  may have grooves, concaves, convexes, and the like. The grooves on the surface  121   a  along the x axis may be made to stabilize a slide operation by the finger, for example. Further, the concave/convex at the center of the surface  121   a  may allow the operator to sense the whereabout/position of the finger in a tactile manner on the panel  121 , without looking at the operating finger. That allows, in other words, an easy operation of the operation input device  100  for various controls based on the tactile feedback of a reference position from the finger/hand. 
         [0089]    Further, in the above embodiments, each of the strain gauges  151  to  154  of the strain gauge  150  is made from four strain gauge elements  151   a - 151   d,    152   a - 152   d,    153   a - 153   d,  and  154   a - 154   d,  respectively. However, each of the strain gauges  151  to  154  may be made from only one distortion detecting element. That is, four strain gauges  150  may suffice at the least. 
         [0090]    Further, the x/y/z axes respectively defined as the lateral/longitudinal/height directions of the vehicle may be differently defined, depending on the situations. That is, according to the installation position of the operation input devices  100  and  100 A, the x/y/z axes may be associated with the lateral/height/longitudinal directions relative to the vehicle, for example. 
         [0091]    Further, the shape of the operation unit  120  (i.e., of the operation panel  121 ) is not restricted to the cylindrical shape. That is, the shape of the operation unit  120  and/or the operation panel  121  may be a polygonal shape or the like. 
         [0092]    Such changes, modifications, and summarized schemes are to be understood as being within the scope of the present disclosure as defined by appended claims.