Abstract:
A toroidal-type continuously variable transmission includes an input shaft, an input disk and an output disk, plural power rollers, a power roller bearing, an oil passage, and a mesh filter. The input and output disks are supported mutually concentrically with the input shaft and mutually independently rotatably. The plural power rollers are sandwiched between the input disk and the output disks. The power roller bearing rotatably supports the power rollers. The oil passage for leading lubricating oil to the power roller bearing. The mesh filter is provided in the oil passage. Accordingly, the toroidal-type continuously variable transmission can prevent an occurrence of biting-in of foreign substances at a power roller bearing, to thereby increase the life of the power roller bearing.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a toroidal-type continuously variable transmission to be used as, for example, an automotive transmission. 
   A related toroidal-type continuously variable transmission to be used as, for example, an automotive transmission is configured as illustrated in  FIGS. 11 and 12 . That is, an input disk  2  and an output disk  3  are rotatably supported on an input shaft  1 , which is connected to a drive source (not shown) such as an engine, through a needle roller bearing. A cam plate  4  is spline-engaged with the input shaft  1  on the back-surface side of the input disk  2 . A roller  5  is interposed between the cam plate  4  and the input disk  2 . A loading cam or hydraulic loading pressing mechanism  6  for pressing the input disk  2  against an output disk  3  is provided therebetween. 
   Trunnions  8   a  and  8   b  each swinging about a pivot shaft  7  are provided between the input disk  2  and the output disk  3 . A displacement shaft  9  is provided in each of the trunnions  8   a  and  8   b  through a radial needle roller bearing  8 . A power roller  10  is rotatably supported on each of the displacement shafts  9  through an associated needle roller bearing  9   a . Each of these power rollers  10  has a traction portion contacting the input disk  2  and the output disk  3  and is rolling-contacted therebetween in such a way as to tiltably rotate. 
   A power roller bearing  11  is provided between the power roller  10  and each of the trunnions  8   a  and  8   b . This power roller bearing  11  allows the power roller  10  to rotate, while supporting a thrust load applied to the power roller  10 . A plurality of balls  12  of such a power roller bearing  11  are held by an annular retainer  14  provided between an annular outer ring  13 , which is provided at the side of each of the trunnions  8   a  and  8   b , and the power roller  10  serving as a rotary portion. A radial bearing  16  is provided on a yoke  15  for tiltingly rotatably supporting each of the trunnions  8   a  and  8   b , which supports the pivot shaft  7 . 
   A valve body is placed under the input disk and the output disk. A mechanism for controlling a height position of the power roller is built into this valve body. This mechanism comprises an actuator, a hydraulic control valve for driving this actuator, and so on. 
   In the toroidal-type continuously variable transmission, power is transmitted between the power roller and each of the input disk and the output disk by interposing an oil film therebetween and using a shearing force of this oil film so as to secure traction. There are known techniques of thus providing a lubricating system in a toroidal-type continuously variable transmission, in which lubricating oil collected and stored in an oil pan is sucked up by an engine-driven oil pump having a line filter provided at the suction side thereof, and in which the lubricating oil is then supplied to the traction surfaces of an input disk and an output disk, and also a traction surface of a power roller through oil passages provided in drive rods of trunnions, (see, for example, the U.S. Pat. No. 6,238,318 and JP-A-2002-286110). 
   As described above, foreign substances, whose sizes are equal to or more than a predetermined size, can be eliminated by providing the line filter at the suction side of the oil pump. However, in a case where foreign substances unremoved by the line filter or burrs remain in the oil passage from the line filter to an oil passage outlet, or where dust enters there during fabrication of the transmission, foreign substances blow off to the power roller together with the lubricating oil. 
   The power roller bearing of the toroidal-type continuously variable transmission is used especially under a high bearing pressure at a high revolution rate. Thus, the related toroidal-type continuously variable transmission has a drawback in that such biting-in of foreign substances decreases the life of the power roller bearing. 
   SUMMARY OF THE INVENTION 
   The present invention is accomplished in view of the aforementioned circumstances. Accordingly, an object of the invention is to provide a toroidal-type continuously variable transmission enabled to prevent an occurrence of biting-in of foreign substances at a power roller bearing to thereby increase the life of the power roller bearing. 
   To achieve the foregoing object, according to an aspect of the invention, there is provided a toroidal-type continuously variable transmission that comprises an input shaft, an input disk and an output disk, which are supported mutually concentrically with the input shaft and mutually independently rotatably, plural power rollers sandwiched between the input disk and the output disk, a power roller bearing for rotatably supporting the power rollers, an oil passage for leading lubricating oil to the power roller bearing, and a mesh filter and a magnet member provided in the oil passage. 
   According to another aspect of the invention, there is provided a toroidal-type continuously variable transmission that comprises an input shaft, an input disk and an output disk, which are supported mutually concentrically with the input shaft and mutually independently rotatably, plural power rollers sandwiched between the input disk and the output disk, a power roller bearing for rotatably supporting the power rollers, an oil passage for leading lubricating oil to the power roller bearing, and a mesh filter and a magnet member provided in the oil passage. 
   Preferably, the toroidal-type continuously variable transmission according to the invention includes a seal member provided on the outer peripheral surface of the power roller bearing. 
   Preferably, the toroidal-type continuously variable transmission according to the invention includes a mesh member and a magnet member is provided in the oil passage. 
   Preferably, the toroidal-type continuously variable transmission according to the invention includes a seal member provided on the outer peripheral surface of the power roller bearing, and a mesh member and a magnet member provided in the oil passage. 
   According to the invention, foreign substances passing through the line filter and dust, burrs, iron powder and so on, which remain at the midway of the oil passage, can be removed by providing a mesh filter and/or a magnet member, which are used for trapping foreign substances, in a part between the line filter and the oil passage for supplying lubricating oil to the power roller bearing. Consequently, the invention can prevent foreign substances from blowing off to the power roller together with lubricating oil. 
   BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1  shows a first embodiment of the invention and is a longitudinally sectional side view illustrating a trunnion of the first embodiment; 
     FIG. 2A  is an enlarged longitudinally sectional side view illustrating a valve body of the first embodiment, and  FIGS. 2B and 2C  are longitudinally sectional side views each illustrating a modification of the first embodiment; 
   In  FIG. 3 ,  FIG. 3A  shows a second embodiment of the invention and is a longitudinally sectional side view illustrating a drive rod of the second embodiment and  FIGS. 3B and 3C  are longitudinally sectional side views each illustrating a modification of the second embodiment. 
     FIG. 4A  shows a third embodiment of the invention and is a longitudinally sectional side view illustrating a trunnion of the third embodiment, and  FIGS. 4B and 4C  are longitudinally sectional side views each illustrating a modification of the third embodiment; 
     FIG. 5A  shows a fourth embodiment of the invention and is a longitudinally sectional side view illustrating a displacement shaft of the fourth embodiment, and  FIGS. 5B and 5C  are longitudinally sectional side views each illustrating a modification of the fourth embodiment; 
     FIG. 6  shows a fifth embodiment of the invention and is a longitudinally sectional side view illustrating a trunnion and a power roller of the fifth embodiment; 
     FIG. 7A  shows a sixth embodiment of the invention and is a longitudinally sectional side view partly illustrating a power roller of the sixth embodiment, and  FIG. 7B  is a longitudinally sectional side view illustrating a modification of the sixth embodiment. 
     FIG. 8  shows a seventh embodiment of the invention and is a longitudinally sectional side view illustrating a trunnion of the seventh embodiment; 
     FIG. 9  shows an eighth embodiment of the invention and is a longitudinally sectional side view illustrating a peripheral part of a power roller of the eighth embodiment; 
     FIG. 10  shows a ninth embodiment of the invention and is a longitudinally sectional side view illustrating a trunnion of the ninth embodiment; 
     FIG. 11  is a longitudinally sectional side view illustrating a related toroidal-type continuously variable transmission; 
     FIG. 12  is a sectional view taken along line X-X of  FIG. 11 ; 
     FIG. 13  is a side view illustrating an input side disk unit for use in a related toroidal-type continuously variable transmission; 
     FIG. 14  is a sectional view taken along line G-G of  FIG. 13 ; 
     FIG. 15  is a sectional view taken along line H-H of  FIG. 13 ; 
     FIG. 16  is a side view illustrating an input side disk unit for use in a toroidal-type continuously variable transmission; 
     FIG. 17  is a sectional view taken along line A-A of  FIG. 16 ; 
     FIG. 18  is a sectional view taken along line B-B of  FIG. 16 ; 
     FIG. 19  is a side view illustrating another input side disk unit for use in a toroidal-type continuously variable transmission; 
     FIG. 20  is a sectional view taken along line C-C of  FIG. 19 ; 
     FIG. 21  is a sectional view taken along line D-D of  FIG. 19 ; 
     FIG. 22  is an enlarged sectional view illustrating a female thread portion of a pressing jig shown in  FIG. 20 ; 
     FIG. 23  is a side view illustrating another input side disk unit for use in a toroidal-type continuously variable transmission; 
     FIG. 24  is a sectional view taken along line E-E of  FIG. 23 ; 
     FIG. 25  is a sectional view taken along line F-F of  FIG. 23 ; and 
     FIG. 26  is an enlarged sectional view illustrating a female thread portion of a pressing jig shown in  FIG. 24 . 

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Hereinafter, embodiments of the invention are described with reference to the accompanying drawings. 
     FIGS. 1 and 2A  to  2 C show a first embodiment of the invention.  FIG. 1  is a longitudinally sectional side view illustrating a trunnion of the first embodiment.  FIGS. 2A to 2C  are enlarged longitudinally sectional side views each illustrating a valve body. Incidentally, the same constituent parts as those of the related toroidal-type continuously variable transmission are designated by the same reference characters. Thus, the description thereof is omitted herein. 
   As shown in  FIG. 1 , paired pivot shafts  22 , which are disposed concentrically with each other, are provided in both end portions of a trunnion  21 . An outer ring  23  is placed around these pivot shafts  22  concentrically therewith. Radial needle roller bearings  25  are configured by rollably providing a plurality of needle rollers  24  between the inner circumferential surface of the outer ring  23  and the outer circumferential surface of each of the pivot shafts  22 . Each of the pivot shafts  22  of the trunnion  21  is rotatably supported through the radial needle roller bearing  25  by a yoke  26  serving as a trunnion support member. 
   A fixing hole  27  extending in an axial direction is provided in the bottom portion of the pivot shaft  22 . The top portion of a drive rod  28  is inserted into this fixing hole  27 . The drive rod  28  is integrally connected to the pivot shaft  22  through a pin  29  penetrating therethrough in a direction perpendicular to the axial direction. 
   An oil passage  30  is provided in the shaft center of the drive rod  28  in such a way as to axially pass therethrough. The top portion of this oil passage  30  communicates with an oil passage  31  provided in the trunnion  21 , so that the lubricating oil is supplied to a radial needle roller bearing  8  and a power roller bearing  11 . The bottom portion of this oil passage  30  communicates with an oil passage  34  in a valve body  33  through a through hole  32  radially penetrating through the drive rod  28 . 
   A hydraulic piston  35  is provided at the bottom portion of the drive rod  28 . The valve body  33  is divided into an upper valve body  33   a  and a lower valve body  33   b . A drive cylinder  36  for accommodating the hydraulic piston  35  is provided along a dividing plane therebetween. An upper part of the drive cylinder  36  communicates with the inner space of a guide barrel  37  provided in the upper valve body  33   a . The space between the inner circumferential surface of this guide barrel  37  and a boss portion  38  of the hydraulic piston  35  is sealed with a sealant  39 . A lower part of the drive cylinder  36  communicates with the inner space of a guide barrel  40  provided in the lower valve body  33   b . The space between the inner circumferential surface of this guide barrel  40  and a boss portion  38  of the hydraulic piston  35  is sealed with a sealant  41 . 
   The oil passage  34  provided in the valve body  33  communicates with an engine-driven oil pump  43 , which has a line filter  42  provided at the suction side thereof, through piping  44 . The lubricating oil is then pressure-fed to the passages  34 ,  30 , and  31 , which serve as lubricating systems, by the oil pump  43  in this order. Thus, the lubricating oil is supplied to the radial needle roller bearing  8  and the power roller bearing  11  of the power roller  12 . Also, the lubricating oil is supplied to the traction surfaces of the input disk  2 , the output disk  3 , and the power roller  10 . 
   An oil passage outlet  31   a  of the oil passage  31  provided in the trunnion  21  is opened in an inner surface  21   a  of the trunnion  21 . A cavity portion  45  is provided in the displacement shaft  9 , which faces this oil passage outlet  31   a , eccentrically with the shaft center thereof in such a way as to axially extend. An oil supply port  46  opened in the outer circumferential surface of the displacement shaft  9  is provided in this cavity portion  45 . The lubricating oil supplied to the cavity portion  45  from the oil passage outlet  31   a  is supplied to the power roller bearing  11  and the needle roller bearing  9   a  from the oil supply port  46 . 
   As shown in  FIG. 2A , a mesh filter  47  for trapping foreign substances having passed through the line filter and also trapping dust, burrs, iron powder and so on, which remain at the midway of the oil passage  34 , is provided at a place close to the discharge side of the oil passage  34  of the lower valve body  33   b , that is, to the guide barrel  37 . In consideration of the life of the power roller bearing  11 , the fluidity of the lubricating oil, and the clogging of the mesh filter  47 , preferably, the mesh size of the mesh filter  47  is 50 μm to 200 μm. 
     FIG. 2B  shows a first modification of the first embodiment. One or plural magnet members  48  are provided along the bottom of the inner space of the oil passage  34  formed in the lower valve body  33   b . This magnet member  48  can adsorb burrs and ferrous foreign substances and also can reduce foreign materials in the lubricating oil. 
     FIG. 2C  shows a second modification of the first embodiment. A mesh filter  47  for trapping foreign substances having passed through the line filter  42  and also trapping dust, burrs, iron powder and so on, which remain at the midway of the oil passage  34 , is provided at a place close to the discharge side of the oil passage  34  of the lower valve body  33   b , that is, to the guide barrel  37 . Also, a magnet member  48  is provided along the bottom of the inner space of the oil passage  34 . 
   When lubricating oil is pressure-fed through piping  44  by the engine-driven oil pump  43  having the line filter  42 , the lubricating oil is led to the oil passages  34 ,  30 , and  31  of the lower valve body  33   b  in this order. At that time, foreign substances, such as dust, burrs, iron powder and so on, which remain at the midway of the oil passage  34 ,  30  and  31 , are trapped by the mesh filter  47  or the magnet member  48 . Thus, the foreign substances are not supplied to the radial needle roller bearing  8  and traction surfaces of the power roller bearing  11  of the power roller  12 , the input disk  2 , the output disk  3 , and the power roller  10 , together with the lubricating oil. Consequently, an occurrence of the biting of foreign substances into the power roller bearing  11  and so on can be prevented. Thus, the life of the power roller bearing  11  and so on can be lengthened. 
     FIG. 3A  shows a second embodiment of the invention, in which a mesh filter  47  similar to that of the first embodiment is installed at an inlet  30   a  of the oil passage  30  provided in such a way as to extend in the axial direction of the drive rod  28 . 
     FIG. 3B  shows a first modification of the second embodiment. In the oil passage  30  in such a way as to extend in the axial direction of the drive rod  28 , one or plural magnet members  48  similar to those of the first embodiment are provided. 
     FIG. 3C  shows a second modification of the second embodiment. At the inlet  30   a  of the oil passage  30  provided in such a way as to extend in the axial direction of the drive rod  28 , a mesh filter  47  similar to that of the first embodiment is provided. Also, in the oil passage  30  in such a way as to extend in the axial direction of the drive rod  28 , one or more magnet members  48  similar to those of the first embodiment are provided. 
     FIG. 4A  shows a third embodiment of the invention, in which a mesh filter  47  similar to that of the first embodiment is installed at an outlet  30   a  of the oil passage  31  provided in the trunnion  21 . 
     FIG. 4B  shows a first modification of the third embodiment of the invention, in which one or more magnet members  48  similar to those of the first embodiment is installed at an outlet  30   a  of the oil passage  31  provided in the trunnion  21 . 
     FIG. 4C  shows a second modification of the third embodiment of the invention. At an outlet  31   a  of the oil passage  31  provided in the trunnion  21 , a mesh filter  47  similar to that of the first embodiment is provided. Also, in the oil passage  31  provided in the trunnion  21 , one or more magnet members  48  similar to those of the first embodiment are provided. 
     FIG. 5A  shows a fourth embodiment of the invention, in which a mesh filter  47  similar to that of the first embodiment is provided at an entrance  45   a  of a cavity portion  45  of the displacement shaft  9 . 
     FIG. 5B  shows a first modification of the fourth embodiment. In the cavity portion  45  of the displacement shaft  9 , one or more magnet members  48  similar to those of the first embodiment are provided. 
     FIG. 5C  shows a second modification of the fourth embodiment. In the entrance  45   a  of the cavity portion  45  of the displacement shaft  9 , one or more magnet members  48  similar to those of the first embodiment are provided. Also, in the cavity portion  45  of the displacement shaft  9 , one or more magnet members  48  similar to those of the first embodiment are provided. 
     FIG. 6  shows a fifth embodiment. A mesh filter  47  similar to that of the first embodiment is provided between the inner surface  21   a  of the trunnion  21  and the back surface of the power roller  10  in such a manner as to face the oil passage outlet  31   a  of the oil passage  31  provided in the trunnion  21 . 
     FIG. 7A  shows a sixth embodiment of the invention. A seal member  49  is provided on an outer periphery of the power roller bearing  11 . This seal member  49  is annular and has an end portion fixed to the power roller  10 , and also has the other end portion lapped around the outer periphery of the outer ring  13 . This seal member  49  can prevent foreign substances, which are gathered up into the lubricating oil, from falling and getting mixed into the lubricating oil when the power roller bearing  11  stops rotating. During rotation of the power roller bearing  11 , foreign materials do not enter the power roller bearing  11 , because the lubricating oil is scattered from the inside of the power roller bearing  11  to the outside by a centrifugal force. However, even when the rotation of the power roller bearing  11  is stopped, lubricating oil is supplied thereto. At that time, foreign materials may enter the power roller bearing  11  from the outside. However, as described above, foreign materials can be prevented by covering the outer periphery of the power roller bearing  11  with seal member  49  from entering there. 
     FIG. 7B  shows a modification of the sixth embodiment. A seal member  49  is provided on the outer periphery of the power roller bearing  11 . This seal member  49  is similar to that of the sixth embodiment, and has an end portion fixed to the power roller  10  and also has the other end portion provided close to an end surface of the outer ring  13 . 
   Incidentally, although the seal member  49  has been described in the description of the sixth embodiment, a modification thereof having a combination of this seal member  49  with the mesh filter  47  and the magnet member  48 , which are used in each of the first to fifth embodiments, is more effective. 
     FIG. 8  shows a seventh embodiment of the invention. A mesh filter  47  similar to that provided in each of the first to sixth embodiments is provided at the midway of the oil passage  30  of a shaft provided at the bottom of the trunnion  21 , that is, the drive rod  28 . Thus, burrs or the like produced at the boring of a hole in the drive rod  28  provided at the bottom of the trunnion  21  are not carried to the power roller bearing  11 . Consequently, the lengthening of the life of the power roller bearing  11  can be achieved. 
     FIG. 9  shows an eighth embodiment of the invention. A mesh filter  47  similar to that of each of the first to seventh embodiments is provided between an inner ring  10   a  and the outer ring  13  of the power roller  10  in such a way as to surround the displacement shaft  9 . Thus, foreign substances can be prevented from entering between a ball  12  of the power roller-bearing  11  and a rolling surface thereof. Consequently, the lengthening of the life of the power roller bearing  11  can be achieved. 
     FIG. 10  shows a ninth embodiment of the invention. The outer ring  13  of the power roller  10  and the displacement shaft  9  are integrally formed. A mesh filter  47  similar to that of the first to eighth embodiments is provided in the cavity portion  45  of the displacement shaft  9 . Usually, when the outer ring  13  is inserted into the displacement shaft  9 , lubricating oil may flow from the gap therebetween. However, in the case that the outer ring  13  and the displacement shaft  9  of the ninth embodiment are integrally formed, lubricating oil flows only from the cavity portion  45 . Because the mesh filter  47  is provided in this cavity portion  45 , contaminants can be surely eliminated. Also, in this embodiment, a seal member  51  is provided on the outer peripheral portion of a thrust bearing  50  that is disposed between the trunnion  21  and the outer ring  13  of the power roller  10 . Therefore, the lubricating oil can be prevented from flowing from the thrust bearing  50  in a case where the cavity portion  45  is clogged with contaminants, and where the lubricating oil becomes difficult to flow. 
   Incidentally, the invention is not limited to the aforementioned embodiments themselves. In an implementation phase, the invention may be embodied by modifying constituent elements thereof without departing from the gist thereof. Also, various modifications of the invention may be made by appropriate combinations of constituent elements disclosed in the foregoing description of the embodiments. For example, some constituent elements may be removed from all the constituent elements described in the foregoing description of the embodiments. Also, constituent elements of different embodiments may be appropriately combined. 
   Meanwhile, when a toroidal-type continuously variable transmission is assembled, each of constituent parts is assembled to the inside of a casing for accommodating the body of this toroidal-type continuously variable transmission. At that time, in a case where an input side disk unit  150  for use in this toroidal-type continuously variable transmission, which comprises an input shaft  1 , a loading cam  7  to be disposed on this input shaft  1 , a loading roller  43 , a retainer  45 , balls  39  of a ball bearing  41 , a dish spring  8 , balls  17  of a ball spline  6 A and a front input-side disk  2 A and so on is assembled into the casing for accommodating the body of this toroidal-type continuously variable transmission, it is necessary to collectively assemble a unit, which is obtained by preliminarily and temporarily assembling the input side disk unit  500  therefor to the input shaft  1 , into the casing. Otherwise, the constituent parts would be separated from one another and could not be efficiently assembled into the casing. 
   Thus, as illustrated in  FIGS. 13 to 15 , the components of the input side disk unit  150  are temporarily assembled by using a pressing jig  151 , which is placed at the side of an outer surface  107   b  of the loading cam  107 , and a plate-like positioning jig  156 , which is fixed to the pressing jig  151 . 
   As shown in  FIGS. 13 and 14 , the pressing jig  151  comprises a disk-like plate portion  152  having a circular hole  152   a  provided in the central portion thereof, and also comprises a leg portion  153  formed by folding the entire outer peripheral part of this plate portion  152  toward the outer surface of the loading cam  107 . Then, in a state in which the positioning of the loading cam  107 , an input side disk  102 A, and a loading roller  143  is performed in such a way as to minimize a pressing force generated thereamong, two bolts  155 ,  155  are passed through the through holes  152   b ,  152   b  of the plate portion  152 , the through holes  107   c ,  107   c  of the loading cam  107 , and the through holes  145   a ,  145   a  of a retainer  145 . The input side disk  102 A is connected to the pressing jig  151  by screwing end portions of the bolts  155 ,  155  into female threads  102   c ,  102   c  formed in the outer surface of the input side disk  102 A. Thus, the input shaft  101 , the loading cam  107 , the retainer  145 , and the input side disk  102 A are held in an unseparated manner. 
   As shown in  FIG. 15 , a cross-sectionally U-shaped projection portion  156   a  protruding toward an end surface at the side of a flange portion  101   a  of the input shaft  101  is formed at a central portion of the positioning jig  156 . Through holes  156   b ,  156   b , through which two bolts  157 ,  157  are respectively passed, are formed in both end portions of the positioning jig  156 . Also, end portions of the bolts  157 ,  157  are screwed into female threads  152   c ,  152   c  formed in the plate portion  152  of the pressing jig  151 . Consequently, the positioning jig  156  is fixed to the outer surface of the plate portion  152  of the pressing jig  151 . During this state, the projection portion  156   a  of the positioning jig  156  is pressed against an end surface at the side of the flange portion  101   a  of the input shaft  101  trough the circular hole  152   a  of the plate portion  152  of the pressing jig  151 . Consequently, the positioning in the axial direction of the input shaft  101  is achieved. 
   Meanwhile, the input side disk unit  150  is assembled into the casing  150  in a state in which the jigs  151  and  156  are assembled thereto. Thereafter, the jigs  151  and  156  are detached in the casing. At that time, foreign materials, such as abrasion powder and cut powder, are generated when the bolts  155 ,  155 ,  157 ,  157  are detached, because a load is applied from the dish spring  108  on the bolts  155 ,  155 ,  157 ,  157 , so that the female threads  102   c ,  102   c ,  152   c ,  152   c  are grounded. When such foreign materials fall in the casing, biting of the foreign materials into the space between the rolling surfaces, such as that between the input side disk and the power roller and that between an output side disk and the power roller, is caused. Thus, there is a fear of reduction in the life of the toroidal-type continuously variable transmission. 
   Thus, as illustrated in  FIGS. 16 to 18 , the input side disk unit  160  for use in the toroidal-type continuously variable transmission has a pressing jig  161  and a positioning jig  156  fixed to this pressing jig  161  so as to prevent this reduction in the life of the toroidal-type continuously variable transmission. 
   As shown in  FIGS. 16 and 17 , the pressing jig  161  comprises a disk-like plate portion  162  having a circular hole  162   a  formed in the central portion thereof, and also comprises a pair of leg portions  163 ,  163  formed in such a manner as to extend from the outer peripheral edge part of this plate portion  162  toward the outer surface  107   b  of the loading cam  107 . 
   As shown in  FIG. 17 , end parts of the leg portions  163 ,  163  are press-contacted with the outer surface  107   b  of the loading cam  107 . Also, as shown in  FIG. 17 , the leg portions  163 ,  163  are formed in such a manner as to be spaced in a circumferential direction of the plate portion  162  and as to face each other. Consequently, as shown in  FIG. 18 , a space S is formed between the leg portions  163 ,  163 . 
   Two through holes  166 ,  166 , through which bolts  165  and  165  are passed, are formed in the vicinity of the leg portions  163 ,  163 , respectively. Slip-off preventing portions  165   a ,  165   a  projecting outwardly are respectively formed at middle portions of the outer circumferential surfaces of bolts  165 ,  165  thereby to prevent the bolts  165 ,  165  from slipping off from the through holes  166 ,  166  of the plate portion  162 . Each of flat washers  194 ,  194  is interposed between the plate portion  162  and an associated one of head portions of the bolts  165 ,  165  so as to prevent the plate portion  162  from being damaged by the friction between the plate portion  162  and each of the head portions of the bolts  165 ,  165  when the bolts  165 ,  165  are fastened. 
   Also, female threads  167 ,  167 , into which the end portions of the bolts  157 ,  157  for fixing the positioning jig  156  to the plate portion  162  are screwed, are respectively formed at places, each of which is spaced 90 degrees in the circumferential direction from an associated one of the through holes  166 ,  166 , in the plate portion  162 . 
   The bolts  165 ,  165  of the pressing jig  161  are passed through the through holes  107   c ,  107   c  of the loading cam  107  and through the through holes  145   a ,  145   a  of the retainer  145  in a state in which the groove portion of a drive-side cam surface  107   a  of the loading cam  107  and the groove portion of a drive-side cam surface  114  of the input side disk  102 A are opposed to each other and in which the loading roller  143  is placed between these groove portions. Also, the end portions of the bolts  165  and  165  are screwed into the female threads  102   c ,  102   c  of the input side disk  102 A, respectively. Thus, the input side disk  102 A is connected to the pressing jig  161 . Consequently, the input shaft  101 , the loading cam  107 , the retainer  145 , and the input side disk  102 A are held in an unseparated manner. 
   When the positioning jig  156  is fixed to the plate portion  162 , the end portions of the bolts  157 ,  157  are screwed into the female threads  167 ,  167  of the plate portion  162  during a state in which the dish spring (a preload generating member)  108  is compressed by pushing the input shaft  101 . Thus, the bolts  157 ,  157  are screwed to the female threads  167 ,  167  without being subjected to a load provided by the dish spring  108 . 
   In the input side disk unit  160 , which is constructed in this manner, for use in a toroidal-type continuously variable transmission, the leg portions  163 ,  163  of the pressing jig  161  are formed at predetermined intervals in the circumferential direction of the plate portion  162 . Thus, even when foreign substances, such as abrasion powder and cut powder produced when the bolts  165 ,  165  are screwed into or unscrewed from the female threads  102   c ,  102   c  of the input side disk  102 A or when the bolts  157 ,  157  are respectively unscrewed from the female threads  167 ,  167  of the plate portion  162 , are accumulated between the loading cam  107  and the pressing jig  161 , the foreign substances can be washed out of the spaces S between the leg portions  163 ,  163 . Thus, an occurrence of the biting of the foreign materials into the space between the rolling surfaces, such as that between the input side disk  102 A and the power roller  111 A or that between the output side disk  103 A and the power roller  111 A, can be prevented. Consequently, the life of the toroidal-type continuously variable transmission can be prevented from being reduced. 
     FIGS. 19 to 22  are views illustrating another input side disk unit for use in a troidal continuously variable transmission, which is subjected to countermeasures. 
   As shown in  FIGS. 19 to 21 , an input side disk unit  170  for use in a troidal continuously variable transmission has a pressing jig  171  and a plate-like positioning jig  156  fixed to this pressing jig  171 . 
   As shown in  FIGS. 19 and 20 , the pressing jig  171  comprises a disk-like plate portion  172  having a circular hole  172   a  provided in the central portion thereof, and also comprises a leg portion  173  formed by folding the entire outer peripheral part of this plate portion  172  toward the outer surface of the loading cam  107 . 
   As shown in  FIG. 20 , two through holes  176 ,  176 , through which bolts  175 ,  175  penetrate, are formed in the plate portion  172  in such a way as to be opposed to each other. Slip-off preventing portions  175   a ,  175   a  projecting outwardly are respectively formed at middle portions of the outer circumferential surfaces of the bolts  175 ,  175  thereby to prevent the bolts  175 ,  175  from slipping off from the through holes  176 ,  176  of the plate portion  172 . Each of flat washers  195 ,  195  is interposed between the plate portion  172  and an associated one of head portions of the bolts  175 ,  175  so as to prevent the plate portion  172  from being damaged by the friction between the plate portion  172  and each of the head portions of the bolts  175 ,  175  when the bolts  175 ,  175  are fastened. 
   End parts of the leg portions  173 ,  173  are press-contacted with the outer surface  107   b  of the loading cam  107 . 
   As shown in  FIGS. 21 and 22 , through holes  177 ,  177 , through which bolts  157 ,  157  for fixing the positioning jig  156  to the outer surface of the plate portion  172  are passed, are respectively formed at places, each of which is spaced 90 degrees in the circumferential direction from an associated one of the through holes  176 ,  176 , in the plate portion  172 . Also, bottomed cylindrical accommodating portions  178 ,  178  for accommodating front edge portions of bolts  157 ,  157  are fixed to parts, at each of which the through hole  177  is formed, in the inner surface of the plate portion  172  by welding or the like. Female threads  178   a ,  178   a , into which the end portions of the bolts  157 ,  157  are screwed, are respectively formed in the inner circumferential surfaces of the accommodating portions  178 ,  178 . Each of female thread portions  179 ,  179  comprises an associated one of the through holes  177 ,  177  and an associated one of the accommodating portions  178 ,  178 . 
   As shown in  FIGS. 19 and 21 , a through hole  156   c , which communicates a shaft hole (the inside)  101   b  of the input shaft  101  with the outside and is larger in diameter than the shaft hole  101   b , is formed in a central part of the projection portion  156   a  of the positioning jig  156 . 
   In the input side disk unit  170  for use in a toroidal-type continuously variable transmission, which is constructed in such a manner, female thread portions  179 ,  179  respectively having bottomed cylindrical accommodating portions  178 ,  178 , each of which accommodates an associated one of the end portions of the bolts  157 ,  157 , are formed in the plate portion  172  of the pressing jig  171 . Thus, foreign materials, which are generated when the bolts  157 ,  157  are fastened to or detached from the female thread portions  179 ,  179 , remain in the accommodating portions  178 ,  178  of the female thread portions  179 ,  179 . Consequently, foreign materials can be prevented from falling in the casing. Therefore, an occurrence of the biting of the foreign materials into the space between the rolling surfaces, such as that between the input side disk  102 A and the power roller  111 A or that between the output side disk  103 A and the power roller  111 A, can be prevented. Consequently, the life of the toroidal-type continuously variable transmission can be prevented from being reduced. 
   Because the through hole  156   c  communicating the shaft hole  101   b  of the input shaft  101  with the outside is formed in the positioning jig  156 , the shaft hole  101   b  of the input shaft  101  can be washed through the through hole  156   c  of the positioning jig  156  during a state wherein the pressing jig  171 , to which the pressing jig  156  is fixed, is attached to the input side disk  102 A. Consequently, foreign materials can be prevented from being accumulated in the shaft hole  101   b  of the input shaft  101 . 
     FIGS. 23 to 26  are views illustrating still another input side disk unit for use in a troidal continuously variable transmission, which is subjected to countermeasures. Incidentally, in  FIGS. 23 to 26 , the same constituent elements as those shown in  FIGS. 16 to 18  are designated by the same reference characters. Thus, the description thereof is simplified. 
   As shown in  FIGS. 23 to 24 , an input side disk unit  180  for use in a troidal continuously variable transmission has a pressing jig  181  and a plate-like positioning jig  156  fixed to this pressing jig  181 . 
   As shown in  FIGS. 23 and 24 , the pressing jig  181  comprises a disk-like plate portion  182  having a circular hole  182   a  formed in the central portion thereof, and also comprises a pair of leg portions  183 ,  183  formed in such a manner as to extend from the outer peripheral edge part of this plate portion  182  toward the outer surface  107   b  of the loading cam  107 . 
   As shown in  FIG. 23 , end parts of the leg portions  183 ,  183  are press-contacted with the outer surface  107   b  of the loading cam  107 . Also, as shown in  FIG. 24 , the leg portions  183 ,  183  are formed in such a manner as to be spaced in a circumferential direction of the plate portion  182  and as to face each other. Consequently, as shown in  FIG. 24 , a space S is formed between the leg portions  183 ,  183 . 
   Two through holes  186 ,  186 , through which bolts  185  and  185  are passed, are formed in the vicinity of the leg portions  183 ,  183  of plate portions  182 , respectively. Slip-off preventing portions  185   a ,  185   a  projecting outwardly are respectively formed at middle portions of the outer circumferential surfaces of the bolts  185 ,  185  thereby to prevent the bolts  185 ,  185  from slipping off from the through holes  186 ,  186  of the plate portion  182 . Each of flat washers  196 ,  196  is interposed between the plate portion  182  and an associated one of head portions of the bolts  185 ,  185  so as to prevent the plate portion  182  from being damaged by the friction between the plate portion  182  and each of the head portions of the bolts  185 ,  185  when the bolts  185 ,  185  are fastened. 
   Also, as shown in  FIGS. 25 and 26 , female threads  187 ,  187 , into which the end portions of the bolts  190 ,  190  for fixing the positioning jig  156  to the plate portion  182  are screwed, are respectively formed at places, each of which is spaced 90 degrees in the circumferential direction from an associated one of the through holes  186 ,  186 , in the plate portion  182 . Bottomed cylindrical accommodating portions  188 ,  188  for accommodating front edge portions of the bolts  190 ,  190  are fixed to parts, at each of which the through hole  187  is formed, in the inner surface of the plate portion  182  by welding or the like. Each of female thread portions  189 ,  189  comprises an associated one of the through holes  187 ,  187  and an associated one of the accommodating portions  188 ,  188 . 
   As shown in  FIG. 26 , nearly annular retaining rings (slip-off preventing portions)  190   a ,  190   a  for preventing the bolts  190 ,  190  from pulling out from the respective accommodating portions  188 ,  188  are provided on the outer peripheral surfaces of end portions of the bolts  190 ,  190 . 
   In the input side disk unit  180  for use in a toroidal-type continuously variable transmission, which is constructed in such a manner, the retaining rings  190   a ,  190   a  are provided on the outer peripheral surfaces of the end portions of the bolts  190 ,  190 , respectively. Thus, even when the bolts  190 ,  190  are unscrewed, the retaining rings  190   a ,  190   a  abut against the inner surface of the plate portion  182 . Thus, the end portions of the bolts  190  can be prevented from slipping off the accommodating portion  189 . Consequently, foreign materials accumulated in the accommodating portions  188 ,  188  can be prevented from going out of the accommodating portions  188 ,  188  and from falling into the casing. 
   While there has been described in connection with the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is aimed, therefore, to cover in the appended claim all such changes and modifications as fall within the true spirit and scope of the invention.