Abstract:
A measuring apparatus for a power roller unit for a toroidal type continuous variable speed transmission, the power roller unit having a trunnion with concentric pivot portions at opposite ends thereof, a pair of bearings disposed around the pivot portions, a displaceable shaft rotatably supporting a pivot support shaft disposed in a hole formed in the trunnion, and a power roller rotatably supported around the pivot support shaft, the measuring apparatus comprising at least one pedestal having an upper surface adapted to support the pivot portions of the trunnion, a hold-down actuator adapted to press the bearings against the upper surface of the at least one pedestal, and a power roller hold-down actuator adapted to press the power roller toward the trunnion, a drive actuator adapted to displace at least one of the power roller and the displaceable shaft, and a measuring device that measures the displacement of the at least one of the power roller and the displaceable shaft.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     A measuring apparatus for a power roller unit for a toroidal type continuous variable speed transmission according to this invention facilitates the work of assembling a toroidal type continuous variable speed transmission utilized, for example, as the speed change unit of a transmission for an automobile or a transmission for various industrial machines and also improves the assembling accuracy to thereby achieve an improvement in performance. 
     2. Related Background Art 
     It has been studied to use a toroidal type continuous variable speed transmission as shown in FIGS. 3 and 4 of the accompanying drawings as a transmission for an automobile. In this toroidal type continuous variable speed transmission, as disclosed, for example, in Japanese Utility Model Application Laid-Open No. 62-71465, an input side disc  2  is supported concentrically with an input shaft  1 , and an output side disc  4  is fixed to the end portion of an output shaft  3  disposed concentrically with the input shaft  1 . Trunnions  6   a,    6   b  pivotally movable about pivots  5   a,    5   b  lying at locations twisted relative to the input shaft  1  and the output shaft  3  are provided inside a casing containing the toroidal type continuous variable speed transmission therein. 
     That is, these trunnions  6   a,    6   b  have the pivots  5   a,    5   b  provided concentrically with each other on the outer sides of the opposite end portions thereof. Also, the base end portions of displaceable shafts  7   a,    7   b  are supported on the intermediate portions of the trunnions  6   a,    6   b  and the trunnions  6   a,    6   b  are pivotally moved about the pivots  5   a,    5   b,  whereby the angles of inclination of the displaceable shafts  7   a,    7   b  are made adjustable. Power rollers  8   a,    8   b  are rotatably supported around the displaceable shafts  7   a,    7   b  supported on the trunnions  6   a,    6   b . These power rollers  8   a,    8   b  are sandwiched between the mutually opposed inner sides  2   a,    4   a  of the input side and output side discs  2  and  4 . Each of these inner sides  2   a,    4   a  has its cross-section forming a concave surface obtained by being rotated along an arc centering around the pivots  5   a,    5   b . The power rollers  8   a,    8   b  formed into spherical convex surfaces and the inner sides  2   a,    4   a  are in contact with each other. Hereinafter, the surfaces of the power rollers  8   a  and  8   b  which are in contact with the inner sides  2   a  and  4   a,  respectively, are referred to as the “peripheral surfaces” of the power rollers  8   a  and  8   b.    
     A pressing apparatus  9  of the loading cam type is provided between the input shaft  1  and the input side disc  2 , and the input side disc  2  is capable of being elastically pressed toward the output side disc  4  by this pressing apparatus  9 . This pressing apparatus  9  is comprised of a cam plate  10  rotatable with the input shaft  1 , and a plurality of (e.g. four) rollers  12   a,    12   b,    12   c  and  12   d  (not shown) held for rolling by a holder  11 . A driving side cam surface  13  which is a concavo-convex surface extending in the circumferential direction is formed on that surface (the left side as viewed in FIGS. 3 and 4) of the cam plate  10  which abuts against the holder  11 , and a driven side cam surface  14  of a similar shape is also formed on the outer side (the right side as viewed in FIGS. 3 and 4) of the input side disc  2 . The plurality of rollers  12   a  to  12   d  are supported for rotation about radial axes with respect to the center of the input shaft  1 . 
     When during the use of the toroidal type continuous variable speed transmission constructed as described above, the cam plate  10  rotates with the rotation of the input shaft  1 , the driving side cam surface  13  presses the plurality of rollers  12   a,    12   b,    12   c  and  12   d  toward the driven side cam surface  14  formed on the outer side of the input side disc  2 . As the result, the input side disc  2  is pressed against the plurality of power rollers  8   a,    8   b  and at the same time, the input side disc  2  is rotated on the basis of the pressing between the driving side and driven side cam surfaces  13 ,  14  and the plurality of rollers  12   a,    12   b,    12   c  and  12   d . The rotation of this input side disc  2  is transmitted to the output side disc  4  through the plurality of power rollers  8   a,    8   b,  and the output shaft  3  fixed to this output side disc  4  is rotated. 
     When the rotational speed ratio (change gear ratio) between the input shaft  1  and the output shaft  3  is to be changed and first, deceleration is to be effected between the input shaft  1  and the output shaft  3 , the trunnions  6   a,    6   b  are pivotally moved in a predetermined direction about the pivots  5   a,    5   b . The displaceable shafts  7   a,    7   b  are then inclined so that as shown in FIG. 3, the peripheral surfaces of the power rollers  8   a,    8   b  may abut against the rather central portion of the inner side  2   a  of the input side disc  2  and the rather outer peripheral portion of the inner side  4   a  of the output side disc  4 , respectively. When conversely, acceleration is to be effected, the trunnions  6   a,    6   b  are pivotally moved in the opposite direction about the pivots  5   a,    5   b . The displaceable shafts  7   a,    7   b  are then inclined so that as shown in FIG. 4, the peripheral surfaces of the power rollers  8   a,    8   b  may abut against the rather outer peripheral portion of the inner side  2   a  of the input side disc  2  and the rather central portion of the inner side  4   a  of the output side disc  4 , respectively. If the angle of inclination of the displaceable shafts  7   a,    7   b  is made intermediate of the angles shown in FIGS. 3 and 4, an intermediate change gear ratio is obtained between the input shaft  1  and the output shaft  3 . 
     Also, FIGS. 5 and 6 of the accompanying drawings show an example of a more embodied toroidal type continuous variable speed transmission described in the microfilm of Japanese Utility Model Application No. 63-69293 (Japanese Utility Model Application Laid-Open No. 1-73552). An input side disc  2  and an output side disc  4  are rotatably supported around a tubular input shaft  15  through needle bearings  16 . Also, a cam plate  10  is spline-engaged with the outer peripheral surface of one end portion (the left end portion as viewed in FIG. 5) of the input shaft  15 , and the movement thereof away from the input side disc  2  is blocked by a flange portion  17 . This cam plate  10  and rollers  12   a,    12   b  together constitute a pressing apparatus  9  of the loading cam type for rotating the input side disc  2  while pressing it toward the output side disc  4  with the rotation of the input shaft  15 . An output gear  18  is coupled to the output side disc  4  by keys  19 ,  19 , and the output side disc  4  and the output gear  18  are rotated in synchronism with each other. 
     In FIG. 6, the opposite end portions of a pair of trunnions  6   a,    6   b  are supported on a pair of support plates  20   a,    20   b  for pivotal movement and displacement in an axial direction (the front-to-back direction of FIG. 5 or the left to right direction as viewed in FIG.  6 ). That is, radial needle bearings  22  which are first radial bearings are provided between the outer peripheral surfaces of pivots  5  secured to the opposite end portions of the trunnions  6   a,    6   b  and the inner peripheral surface of a circular hole  21  formed in each support plate  20 . The outer peripheral surfaces of outer rings  23  constituting these radial needle bearings  22  are fitted as spherical convex surfaces in the circular holes  21  for pivotal movement and axial displacement. 
     In this manner, the displaceable shafts  7   a,    7   b  are supported in circular holes  24   a,    24   b  formed in the intermediate portions of the trunnions  6   a,    6   b  supported for pivotal movement and axial displacement between the pair of support plates  20   a,    20   b . These displaceable shafts  7   a,    7   b  have support shaft portions  25   a,    25   b  and pivotally supporting shaft portions  26   a,    26   b  parallel to and eccentric from each other. The support shaft portions  25   a,    25   b  are rotatably supported inside the circular holes  24   a,    24   b  through radial needle bearings  27   a,    27   b  which are second radial bearings. Also, power rollers  8   a,    8   b  are rotatably supported around the pivotally supporting shaft portions  26   a,    26   b  through radial needle bearings  28   a,    28   b  which are third radial bearings. 
     The pair of displaceable shafts  7   a,    7   b  are provided at locations opposite by 180° relative to the input shaft  15 . Also, the direction in which the pivotally supporting shaft portions  26   a,    26   b  of these displaceable shafts  7   a,    7   b  are eccentric relative to the support shaft portions  25   a,    25   b  is the same direction (the right to left direction as viewed in FIG. 6) with respect to the direction of rotation of the input side and output side discs  2  and  4 . Also, the direction of eccentricity is a direction substantially orthogonal to the direction of disposition of the input shaft  15 . Accordingly, the power rollers  8   a,    8   b  are supported for some displacement in the direction of disposition of the input shaft  15 . As a result, even when the power rollers  8   a,    8   b  tend to be displaced in the axial direction of the input shaft  15  (the left to right direction as viewed in FIG. 5 or the front to back direction of FIG. 6) due to the elastic deformation of the constituent members based on a great load applied to the constituent members in the transmitted state of the rotational force, this displacement can be absorbed without any unreasonable force being applied to each portion. 
     Also, between the outer sides of the power rollers  8   a,    8   b  and the inner sides of the intermediate portions of the trunnions  6   a,    6   b,  thrust ball bearings  29   a,    29   b  which are first thrust bearings and thrust needle bearings  30   a,    30   b  which are second thrust bearings are provided in series with one another with respect to the acting direction of a thrust load (a vertical direction as viewed in FIGS.  5  and  6 ), in the order from the outer sides of the power rollers  8   a,    8   b . The thrust ball bearings  29   a,    29   b  support a load in the thrust direction applied to the power rollers  8   a,    8   b  and yet permit the rotation of these power rollers  8   a,    8   b . Such thrust ball bearings  29   a,    29   b  are comprised of a plurality of balls  31 , circular ring-shaped retainers  32  retaining these balls  31  for rolling movement, and circular ring-shaped outer rings  33 . The inner ring raceway tracks of these thrust ball bearings  29   a,    29   b  are formed on the outer sides of the power rollers  8 , and the outer ring raceway tracks of these thrust ball bearings  29   a,    29   b  are formed on the inner sides of the outer rings  33 . 
     Also, the thrust needle bearings  30   a,    30   b  are comprised of races  34 , retainers  35  and needles  36 . The races  34  and the holders  35  are combined together for some displacement with respect to the rotational direction. Such thrust needle bearings  30   a,    30   b  sandwich the races  34 , between the inner sides of the trunnions  6   a,    6   b  and the outer sides of the outer rings  33   a,    33   b  with the races  34 , abutting against the inner sides of the trunnions  6   a,    6   b . Such thrust needle bearings  30   a,    30   b  support a thrust load applied from the power rollers  8   a,    8   b  to the outer rings  33   a,    33   b  and yet permit the pivotally supporting shaft portions  26   a,    26   b  and the outer rings  33   a,    33   b  to pivotally move about the support shaft portions  25   a,    25   b.    
     Further, driving rods  37   a,    37   b  are coupled to one end portion (the left end portion as viewed in FIG. 6) of the trunnions  6   a,    6   b,  and driving pistons  38   a,    38   b  are secured to the outer peripheral surfaces of the intermediate portions of these driving rods  37   a,    37   b . These driving pistons  38   a,    38   b  are oil-tightly fitted in driving cylinders  39   a  and  39   b,  respectively. 
     In the case of the toroidal type continuous variable speed transmission constructed as described above, the rotation of the input shaft  15  is transmitted to the input side disc  2  through the pressing apparatus  9 . The rotation of this input side disc  2  in turn is transmitted to the output side disc  4  through the pair of power rollers  8   a,    8   b  and further, the rotation of this output side disc  4  is taken out from an output gear  18 . When the rotational speed ratio between the input shaft  15  and the output gear  18  is to be changed, the pair of driving pistons  38   a,    38   b  are displaced in opposite directions. With the displacement of these driving pistons  38   a,    38   b,  the pair of trunnions  6   a,    6   b  are displaced in opposite directions, and for example, the lower power roller  8   b  in FIG. 6 is displaced to the right as viewed in FIG.  6  and the upper power roller  8   a  in FIG. 6 is displaced to the left as viewed in FIG.  6 . As the result, the direction of a tangential force acting on the contact portions between the peripheral surfaces of these power rollers  8   a,    8   b  and the inner sides  2   a  and  4   a  of the input side disc  2  and the output side disc  4 , respectively, is changed. With the change in the direction of this force, the trunnions  6   a,    6   b  pivotally move in opposite directions about the pivots  5   a,    5   b  pivotally supported on the support plates  20   a,    20   b.  As the result, as shown in FIGS. 3 and 4, the contact positions between the peripheral surfaces of the power rollers  8   a,    8   b  and the aforementioned inner sides  2   a,    4   a  change, and the rotational speed ratio between the input shaft  15  and the output gear  18  changes. 
     The adjustment of the rotational speed ratio between the input shaft  15  and the output gear  18  to a desired value is effected by regulating the amounts of movement of the driving pistons  38   a,    38   b . The regulation of the amounts of movement of these driving pistons  38   a,    38   b  is effected by the engagement between precess cams, not shown, fixed to the end portions or the intermediate portions of the driving rods  37   a,    37   b  and the spools or the sleeves of spool values, not shown. Also, when as described above, the transmission of the rotational force is to be effected between the input shaft  15  and the output gear  18 , the power rollers  8   a,    8   b  are displaced axially of the input shaft  15  on the basis of the elastic deformation of each constituent member and the displaceable shafts  7   a,    7   b  pivotally supporting these power rollers  8   a,    8   b  slightly rotate about the support shaft portions  25   a,    25   b . As the result of this rotation, the outer sides of the outer rings  33   a,    33   b  of the thrust ball bearings  29   a,    29   b  and the inner sides of the trunnions  6   a,    6   b  are displaced relative to each other. Since the thrust needle bearings  30   a,    30   b  are present between these outer sides and inner sides, the force required for this relative displacement is small. Accordingly, the force for changing the angles of inclination of the displaceable shafts  7   a,    7   b  as described above may be small. 
     When assembling the toroidal type continuous variable speed transmission constructed and acting as described above, the constituent parts have heretofore been assembled in order inside a housing  40  (FIG. 6) containing the main body of this toroidal type continuous variable speed transmission therein. Accordingly, the deviation of the positional relations among the respective portions based on the integration of the dimensional errors of the constituent parts, and further whether the constituent parts function properly could be confirmed only after these constituent parts were all assembled in the housing  40 . In contrast with this, to secure the efficiency and durability of the toroidal type continuous variable speed transmission, the positional relations among the constituent parts must be maintained highly accurate. Therefore, when the deviation of the positional relations of the respective portions becomes great on the basis of the integration of the dimensional errors of the constituent parts, the disassembly and reassembly of the toroidal type continuous variable speed transmission assembled in the housing  40  must be done to make this deviation small by the combination with other parts. When the work of assembling the toroidal type continuous variable speed transmission is done in this manner, the work of manufacturing the toroidal type continuous variable speed transmission is cumbersome and a reduction in cost cannot be achieved. 
     In view of such circumstances, a power roller unit  41  for a toroidal type continuous variable speed transmission as shown in FIGS. 7 and 8 of the accompanying drawings is described in Japanese Patent Application Laid-Open No. 11-153203. This power roller unit  41  for a toroidal type continuous variable speed transmission has radial needle bearings  22   a,    22   b  which are first radial bearings provided around pivots  5   b,    5   b  secured concentrically with each other to the opposite end surfaces of a trunnion  6 . Also, the support shaft portion  25  of a displaceable shaft  7  comprising a support shaft portion  25  and a pivotally supporting shaft portion  26  parallel to and eccentric from each other is rotatably supported in a circular hole  24  formed in the intermediate portion of the trunnion  6  in a direction perpendicular to the axial direction of the pivots  5   a,    5   b,  through a radial needle bearing  27  which is a second radial bearing. 
     Also, a power roller  8  is rotatably supported around the pivotally supporting shaft portion  26  through a radial needle bearing  28  which is a third radial bearing. Also, between the outer side of the power roller  8  and the inner side of the intermediate portion of the trunnion  6 , a thrust ball bearing  29  and a thrust needle bearing  30  which are first and second thrust bearings, respectively, are provided in series with each other with respect to the acting direction of a thrust load. The trunnion  6 , the radial needle bearings  22 ,  27 ,  28 , the displaceable shaft  7 , the power roller  8 , the thrust ball bearing  29  and the thrust needle bearing  30  which are parts discrete from one another are pre-assembled into the positional relation after the completion of the assembly of the toroidal type continuous variable speed transmission before they are assembled to the toroidal type continuous variable speed transmission. 
     In the case of the power roller unit  41  for the toroidal type continuous variable speed transmission constructed as described above, the deviation of the positional relations among the respective portions based on the integration of the dimensional errors of the constituent parts, and further whether the constituent parts function properly can be confirmed before these constituent parts are assembled in the housing. Accordingly, without requiring the cumbersome work of disassembling and reassembling the entire toroidal type continuous variable speed transmission, the positional relations among the constituent parts can be maintained highly accurate to secure the efficiency and durability of the toroidal type continuous variable speed transmission. 
     SUMMARY OF THE INVENTION 
     As described above, Japanese Patent Application Laid-Open No. 11-153203 describes a power roller unit for a toroidal type continuous variable speed transmission which can efficiently effect the assembly of a toroidal type continuous variable speed transmission of high performance, but does not describe means capable of efficiently measuring whether the constituent parts of this power roller unit for the toroidal type continuous variable speed transmission function properly. 
     In view of such circumstances, the present invention has been made in order to realize a measuring apparatus which can efficiently measure whether the constituent parts of the above-described power roller unit for the toroidal type continuous variable speed transmission function properly. 
     Any of the measuring apparatuses of the present invention for a power roller unit for a toroidal type continuous variable speed transmission is for measuring the movement of the power roller unit for a toroidal type continuous variable speed transmission before the assembly thereof to the toroidal type continuous variable speed transmission. Also, the power roller unit for the toroidal type continuous variable speed transmission which is the object of measurement comprises a trunnion having concentric pivots secured to the opposite end surfaces thereof, a pair of first radial bearings provided around these two pivots, a circular hole formed in the intermediate portion of the trunnion in a direction perpendicular to the axial direction of the pivots, and a support shaft portion and a pivotally supporting shaft portion parallel to and eccentric from each other, and is provided with a displaceable shaft rotatably supporting the support shaft portion inside the circular hole through a second radial bearing, a power roller rotatably supported around the pivotally supporting shaft portion through a third radial bearing, and first and second thrust bearings provided between the outer side of this power roller and the inner side of the intermediate portion of the trunnion in series with each other with respect to the acting direction of a thrust load. The trunnion, the first, second and third radial bearings, the displaceable shaft, the power roller and the first and second thrust bearings which are parts discrete from one another are pre-assembled into the positional relation after the completion of the assembly of the toroidal type continuous variable speed transmission before they are assembled to the toroidal type continuous variable speed transmission. 
     Particularly, the measuring apparatus for a power roller unit for a toroidal type continuous variable speed transmission is provided with a pair of pedestals, hold-down means for a pivot, hold-down means for a power roller, pivotally driving means and pivotal displacement measuring means, the pedestals support the pivots provided at the opposite end portions of the trunnion on the upper surfaces thereof through the pair of first radial bearings with the power roller positioned above the trunnion. Also, the hold-down means for the pivot holds down the first radial bearings on the upper surfaces of the pedestals. Also, the hold-down means for the power roller holds down the power roller toward the trunnion. Also, the pivotally driving means presses the two diametrically opposite locations of the power roller with respect to the widthwise direction of the trunnion to thereby pivotally displace the power roller about the support shaft portion. Also, the pivotal displacement measuring means measures the amount of displacement of the power roller by the pivotally driving means. 
     Also, a measuring apparatus for a power roller unit for a toroidal type continuous variable speed transmission is provided with axially driving means and axial direction displacement measuring means, a pair of pedestals, hold-down means for a pivot and hold-down means for a power roller. The axially driving means presses the axially opposite end surfaces of the displaceable shaft to thereby displace this displaceable shaft axially thereof. Further, the axial direction displacement measuring means measures the amount of displacement of the displaceable shaft by the axially driving means with respect to the axial direction thereof. 
     According to the measuring apparatus of the present invention for a power roller unit for a toroidal type continuous variable speed transmission constructed as described above, the amount of displacement for judging whether the constituent parts of the power roller unit for the toroidal type continuous variable speed transmission function properly can be measured efficiently. 
     First, according to the measuring apparatus of the invention, the amount of pivotal displacement for judging Whether a displacement shaft rotatably supporting a power roller around the pivotally supporting shaft portion thereof through a third radial bearing is properly pivotally displaced about a support shaft portion supported relative to a trunnion by a second radial bearing provided inside a circular hole can be measured efficiently. 
     Also, according to the measuring apparatus of the invention, the amount of axial displacement for judging whether the displaceable shaft supporting the power roller for rotation and pivotal displacement relative to the trunnion is assembled to the trunnion and the power roller with a desired axial gap can be measured efficiently. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partly omitted side view of an apparatus according to Embodiment 1 as it is seen from its end surface side. 
     FIG. 2 shows a cross-section cut by line  2 — 2  in FIG.  1 . 
     FIG. 3 is a side view showing the basic construction of a toroidal type continuous variable speed transmission of the conventional type in the state during maximum deceleration. 
     FIG. 4 is a side view showing the basic construction of the toroidal type continuous variable speed transmission of the conventional type in the state during maximum acceleration. 
     FIG. 5 is a cross-sectional view in the specific structure of an example of the toroidal type continuous variable speed transmission of the conventional type. 
     FIG. 6 shows a cross-section cut by line  6 — 6  in FIG.  5 . 
     FIG. 7 is a cross-sectional view of an example of the toroidal type continuous variable speed transmission of the conventional type. 
     FIG. 8 is a cross-sectional view of the toroidal type continuous variable speed transmission shown in FIG. 7 as it is seen from the right side of FIG.  7 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 and 2 show a first embodiment of the present invention. The shown embodiment shows a measuring apparatus incorporating therein both of an apparatus for measuring the amount of pivotal displacement of a power roller  8  and an apparatus for measuring the amount of axial displacement of a displaceable shaft  7 . When constructing an actual measuring apparatus, it is advantageous for achieving the efficiency of measuring work to make the above-mentioned amount of pivotal displacement and the above-mentioned amount of axial displacement measurable by a measuring apparatus, as in the shown embodiment. A constituent portion for measuring the amount of pivotal displacement appears in FIG. 1, and a constituent portion for measuring the amount of axial displacement appears in FIG.  2 . 
     First, reference is had chiefly to FIG. 1 to describe the constituent portion for measuring the amount of pivotal displacement of the power roller  8 . This constituent portion for measuring the amount of pivotal displacement of the power roller  8  is provided with a pair of pedestals  42  such as V blocks (see FIGS.  1  and  2 ). The pedestals  42  support on the upper surface thereof a pair of pivots  5  provided concentrically with each other at the opposite end portions of a trunnion  6  constituting the power roller unit  41  for the toroidal type continuous variable speed transmission as shown in FIGS. 7 and 8, through radial needle bearings  22 , with the power roller  8  positioned above the trunnion  6 . 
     Above such pedestals  42 , radial needle bearing hold-down actuators  43  (see FIG. 2) which are hold-down means for pivots are longitudinally (vertically) disposed by the cylinder portions  44  of these actuators  43  being supported on a fixed portion (not shown) such as a frame. These two radial needle bearing hold-down actuators  43  are extended and outer rings  23  constituting the radial needle bearings  22  are held down on the pedestals  42  by hold-down pads  46  provided on the tip end portions (the lower end portions) of output rods  45 , whereby the pivots  5  can be supported in a predetermined positional relation on the upper surfaces of the pedestals  42 . 
     Also, in such a manner as to sandwich the trunnion  6  supported so as to be hung over the pedestals  42  from the width wisely opposite sides, a pair of right and left pivotally movable actuators  47   a,    47   b  constituting pivotally driving means are laterally (horizontally) disposed by the cylinder portions  48   a,    48   b  of these pivotally movable actuators  47   a,    47   b  being supported on the fixed portion (not shown) such as the frame. The pivotally movable actuators  47   a,    47   b  are extended and the two diametrically opposite locations of the outer peripheral edge of the power roller  8  can be pressed diametrically inwardly of this power roller  8  by pressing pads  50   a,    50   b  provided on the tip end portions of output rods  49   a,    49   b.    
     The pivotally driving means constituted by the pair of pivotally movable actuators  47   a,    47   b  as described above changes the pressure of working fluid fed into these pivotally movable actuators  47   a,    47   b,  and changes the force with which the pivotally movable actuators  47   a,    47   b  press the power roller  8 , thereby pivotally displacing this power roller  8  about the support shaft portion  25  constituting the displaceable shaft  7  (see FIG.  2 ). That is, if the pressure of the working fluid supplied to the right pivotally movable actuator  47   a  as viewed in FIG. 1 is made high and the pressure of the working fluid supplied to the left pivotally movable actuator  47   b  is made low, the power roller  8  is pivotally displaced to the left as viewed in FIG.  1 . If conversely, the pressure of the working fluid supplied to the left pivotally movable actuator  47   b  as viewed in FIG. 1 is made high and the pressure of the working fluid supplied to the right pivotally movable actuator  47   a  is made low, the power roller  8  is pivotally displaced to the right as viewed in FIG.  1 . It is also possible to displace the power roller  8  to a position in which it interferes with the trunnion  6  when this power roller  8  is pivotally displaced as described above, but it is also possible not to cause the power roller  8  and the trunnion  6  to interfere with each other, by adjusting the strokes of the two pivotally movable actuators  47   a,    47   b.    
     The amount of pivotal displacement of the power roller  8  about the support shaft portion  25  by the pivotally driving means as described above is measured by a length measuring machine  51  such as a linear scale constituting pivotal displacement measuring means. This length measuring machine  51  has the tip end of its gauge head  52  rammed against a backing plate  53  fixed to a pressing pad  50  with its main body portion supported on a fixed portion such as the frame, not shown. Accordingly, the length measuring machine  51  detects the amount of pivotal displacement of the power roller  8  as the amount of displacement of the pressing pad  50 . 
     Next, reference is had chiefly to FIG. 2 to describe a constituent portion for measuring the amount of axial displacement of the displaceable shaft  7 . The amount of axial displacement of this displaceable shaft  7  is important for judging whether this displaceable shaft  7  can be smoothly pivotally displaced about the support shaft portion  25  thereof relative to the trunnion  6 , whether the power roller  8  can smoothly rotate about the pivotally supporting shaft portion  26  of the displaceable shaft  7 , and whether there is any excessive backlash in the mounted portion of this displaceable shaft  7 . That is, the trunnion  6 , the displaceable shaft  7  and the power roller  8 , as shown in FIG. 2, are unseparably coupled together by washers  55  being supported on the end portions of the support shaft portion  25  and pivotally supporting shaft portion  26  constituting the displaceable shaft  7  by snap rings  54 . Accordingly, if the spacing between these washers  55  and the partner surfaces is too short, the pivotal displacement o f the displaceable shaft  7  and the rotation of the power roller  8  will not smoothly take place. If conversely, the spacing between the washers  55  and the partner surfaces is too long, excessive backlash will occur to the mounted portion of the displaceable shaft  7 . Also, a gap present in the fitted portion between a flange portion  68  provided on the intermediate portion of the displaceable shaft  7  and the outer ring  33  may cause a similar problem to arise. That is, slight gaps of a regulated size with respect to the axial direction of the displaceable shaft  7  are present between the washer  55  fitted on the end portion of the support shaft portion  25  and the outer side of the trunnion  6 , between the washer  55  fitted on the end portion of the pivot shaft portion  26  and the inner end surface of the power roller  8 , and in the fitted portion between the flange portion  68  provided on the intermediate portion of the displaceable shaft  7  and the outer ring  33 . On the basis of the presence of the gaps in these respective portions, the displaceable shaft  7  incorporated in the power roller unit for the toroidal type continuous variable speed transmission is axially displaced. So, by measuring the amount of axial displacement, whether the gaps present between the washers  55  and the partner surfaces, and in the fitted portion between the flange  68  and the outer ring  33  are proper is judged. 
     In order to measure the amount of axial displacement for such a purpose, a power roller hold-down actuator  56  which is hold-down means for the power roller is longitudinally (vertically) disposed by supporting the cylinder portion  57  of this power roller hold-down actuator  56  on a fixed portion such as the frame, not shown. The power roller hold-down actuator  56  is extended and the power roller  8  is held down toward the trunnion  6  by a hold-down pad  59  provided on the tip end portion (the lower end portion) of an output rod  58 , whereby the power roller  8  can be prevented from floating up during the work of measuring the amount of axial displacement. The hold-down pad  59  also continues to hold down the power roller  8  when this power roller  8  is pivotally displaced by the aforedescribed pivotally driving means. Accordingly, the hold-down pad  59  is made of a material having a low coefficient of friction such as polyamide resin like MC nylon so that the inner end surface (the upper end surface as viewed in FIGS. 1 and 2) of the power roller  8  may not be damaged with the work of measuring the amount of pivotal displacement. 
     A pair of lower and upper shaft driving actuators  61   a,    61   b  constituting axially driving means with the displaceable shaft  7  sandwiched between the axially opposite sides are longitudinally (vertically) disposed by supporting the cylinder portions  62 ,  62  of these shaft driving actuators  61   a,    61   b  on a fixed portion such as the frame, not shown. The shaft driving actuators  61   a,    61   b  are extended and the axially opposite end surfaces of the displaceable shaft  7  can be pressed toward the axially central side of this displaceable shaft  7  by pressing pads  64 ,  64  provided on the tip end portions of output rods  63 ,  63 . 
     The axially driving means constituted by the pair of shaft driving actuators  61   a,    61   b  as described above changes the pressure of working fluid fed into these two shaft driving actuators  61   a,    61   b,  and changes the force with which these two shaft driving actuators  61   a,    61   b  press the displaceable shaft  7 , thereby axially displacing this displaceable shaft  7 . That is, if the pressure of the working fluid supplied to the lower shaft driving actuator  61   a  as viewed in FIG. 2 is made high and the pressure of the working fluid supplied to the upper shaft driving actuator  61   b  is made low, the displaceable shaft  7  is displaced upwardly as viewed in FIG.  2 . If conversely, the pressure of the working fluid supplied to the upper shaft driving actuator  61   b  as viewed in FIG. 2 is made high and the pressure of the working fluid supplied to the lower shaft driving actuator  61   a  is made low, the displaceable shaft  7  is displaced downwardly as viewed in FIG.  2 . 
     The amount of axial displacement of the displaceable shaft  7  by the axially driving means as described above is measured by a length measuring machine  65  such as a linear scale constituting axial displacement measuring means. This length measuring machine  65  has the tip end of its gauge head  66  rammed against a backing plate  67  fixed to a pressing pad  64  with its main body portion supported on a fixed portion such as the frame, not shown. Accordingly, the length measuring machine  65  detects the amount of axial displacement of the displaceable shaft  7  as the amount of displacement of the pressing pad  64 . 
     According to the measuring apparatus of the present invention for a power roller unit for a toroidal type continuous variable speed transmission constructed as described above, whether the constituent parts of the power roller unit for the toroidal type continuous variable speed transmission function properly can be efficiently measured. First, the amount of pivotal displacement for judging whether the power roller  8  rotatably supported around the pivot shaft portion  26  of the displaceable shaft  7  is properly pivotally displaced, in other words, whether the displaceable shaft  7  rotatably supporting this power roller  8  through the radial needle bearing  28  is properly pivotally displaced about the support shaft portion  25  supported relative to the trunnion  6  by the radial needle bearing  27  provided inside the circular hole  24  in the trunnion  6  can be efficiently measured by the constituent portion for measuring the amount of pivotal displacement of the power roller  8  which is shown chiefly in FIG.  1 . 
     Also, the amount of axial displacement for judging whether the displaceable shaft  7  is assembled to the trunnion  6  and the power roller  8  with a desired axial gap can be efficiently measured by the constituent portion for measuring the amount of axial displacement of the displaceable shaft  7  which is shown chiefly in FIG.  2 . These series of measuring operations can be automatically performed and therefore, the stabilization of the performance and an improvement in the reliability of the toroidal type continuous variable speed transmission can be achieved by carrying out the total inspection of the power roller unit  41  for the toroidal type continuous variable speed transmission. 
     The measuring apparatus of the present invention for the power roller unit for the toroidal type continuous variable speed transmission is constructed and acts as described above and therefore, a reduction in the costs of the toroidal type continuous variable speed transmission can be achieved by making the assembling work and inspecting work for the toroidal type continuous variable speed transmission efficient.