Abstract:
A toroidal-type continuously variable transmission has a casing, a rotation shaft, a pair of outer side disks having side surface, supported on the rotation shaft, and rotating in synchronism with the rotation shaft, an inner side disk having two side surfaces, rotatably supported on around a middle portion of the rotation shaft, and rotating relative to the rotation shaft, pluralities of supporting members disposed between the both side surfaces of the inner side disk and the side surfaces of the outer side disks, respectively, and swinging on a pivot shaft disposed so as to be twisted to the rotation shaft, and pluralities of power rollers rotatably supported on the respective supporting members, wherein an outer peripheral face of the inner side disk is provided with a detected portion for detecting rotation of the inner side disk.

Description:
[0001]     The present invention claims foreign priority to Japanese patent application no. P. 2004-050958, filed on Feb. 26, 2004, the contents of which is incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     A toroidal-type continuously variable transmission according to the present invention is utilized as an automatic transmission apparatus for an automobile, or a transmission apparatus for controlling an operating speed of various industrial machines of a pump and the like.  
         [0004]     2. Description of the Related Art  
         [0005]     There is known and partially embodied a toroidal-type continuously variable transmission as a kind of a transmission apparatus constituting a kind of a transmission for an automobile. Further, there has been known various conventional continuously variable transmission apparatus each combined with a toroidal-type continuously variable transmission and a planetary gear type transmission. Further, in the various conventional variable transmission apparatus, there is also known a structure that an output side disk is provided with output-side side surfaces, of which a section is in a circular arc shape, at both side surfaces relative to an axial direction, and an input shaft is provided concentrically with a hollow rotating shaft as described in Japanese Patent Unexamined Publications Nos. JP-A-6-174033, JP-A-2002-48205 and JP-A-11-141637, U.S. Pat. No. 6,251,039, U.S. Pat. No. 6,585,619, U.S. Pat. No. 5,607,372 and U.S. Pat. No. 6,099,431 and U.S. Patent Unexamined Publication U.S. 2003/0224895A1.  
         [0006]      FIGS. 7 through 8  show a continuously variable transmission apparatus described in U.S. 2003/0224895A1. First, a continuously variable transmission apparatus of the related art will be explained. In  FIGS. 7 through 8 , positions of sections of one cavity and another cavity differ from each other by 90 degrees relative to a circumferential direction. The continuously variable transmission apparatus comprises a toroidal-type continuously variable transmission  1 , first through third respective planetary gear type transmissions  2  through  4 , an input shaft  5 , a transmitting shaft  6  and an output shaft  7  supported concentrically and rotatably relative to each other. The first and second planetary transmissions  2 ,  3  are provided in a state of being hung between the input shaft  5  and transmitting shaft  6 . The third planetary gear type transmission  4  is provided in a state of being hung between the transmitting shaft  6  and the output shaft  7 , respectively.  
         [0007]     The toroidal-type continuously variable transmission  1  includes a pair of input side disks  8   a ,  8   b , an output side disk  9  of an integrated type and a plurality of power rollers,  10 ,  10 . The two input side disks  8   a ,  8   b  are supported on of the input shaft  5  two portions, which are separated each other relative to an axial direction of the input shaft  5 , so as to be concentric and rotate in synchronize each other, in a state that side face thereof relative to the axial direction, of which sections are in an arc shape, are opposed to each other. The output side disk  9  is supported at a surrounding of a middle portion of the input shaft  5 , and between the two input side disks  8   a ,  8   b  so that the two input side disks  8   a ,  8   b  is concentric with the two input side disks  8   a ,  8   b  and rotate relative to the two input side disks  8   a ,  8   b , in a state in which both side faces relative to the axial direction, of which a section is in an arc shape, are opposed to the one side faces.  
         [0008]     Pluralities of the respective power rollers  10 ,  10  are pinched between the side faces in the axial direction of the output side disk  9  and the one side face in the axial direction of the input side disks  8   a ,  8   b  to be able to transmit power from the two input side disks  8   a ,  8   b  to the output side disk  9 . The respective power rollers  10 ,  10  are rotatably supported respectively on inner side faces of trunnions  12 ,  12  constituting supporting members. Pivot shafts provided at both end portions of the respective trunnions  12 ,  12  are supported by supporting plates  13   a ,  13   b  swingably and displaciably in the axial directions. Further, the two supporting plates  13   a ,  13   b  are supported by supporting posts  14   a ,  14   b  fixed to inside of a casing  15 .  
         [0009]     Both end portions in the axial direction of the output side disk  9  are rotatably supported by a pair of thrust angular ball bearings  11 ,  11 . Accordingly, the pair of supporting posts  14   a ,  14   b  provided concentrically with each other are connected by holding rings  16 , of which a shape is a circular ring, at an opposite side in radial direction of the input shaft  5 . The input shaft  5  is inserted through inner sides of the holding rings  16 . Further, the respective thrust angular ball bearings  11 ,  11  are provided between the respective holding rings  16 ,  16 , which are provided in the respective cavities, and the both end faces in the axial direction of the output side disk  9 .  
         [0010]     The output side disk  9  is engaged with a base end portion (left end portions in  FIGS. 7 through 8 ) of a hollow rotating shaft  17  by a spline. In addition, a rotational force of the output side disk  9  is made to be able to be outputted by inserting the hollow rotating shaft  17  through an inner side of the input side disk  8   b  on a side remote from an engine (right sides of  FIGS. 7 through 8 ). Further, a first sun gear  18  for constituting the first planetary gear type transmission  2  is fixedly provided at a front end portion (right end portions of  FIGS. 7 through 8 ) of the hollow rotating shaft  17  projected from an outer side face of the input side disk  8   b.    
         [0011]     Meanwhile, a first carrier  19  is provided to be hung between the input portion of a front end portion (right end portions of  FIGS. 7 through 8 ) of the input shaft  5 , which is projected from the hollow rotating shaft  17 , and the input side disk  8   b  so as to rotate the input side disk  8   b  and the input shaft  5  synchronizingly with each other. Planetary gears  20  through  22  for constituting the first and the second planetary gear type transmissions  2 ,  3  each constituting a double pinion type are rotatably supported at positions of both side faces in an axial direction of the first carrier  19  having equal intervals in a circumferential direction (generally, positions of three to four portions). A first ring gear  23  is rotatably supported by a surrounding of one half portion (right half portions of  FIGS. 7 through 8 ) of the first carrier  19 .  
         [0012]     In the respective planetary gears  20  through  22 , the planetary gear  20  provided on an inner side in a radial direction of the first carrier  19 , which is proximate to the toroidal-type continuously variable transmission  1  (proximate to left sides of  FIGS. 7 through 8 ), meshes with the first sun gear  18 . Further, the planetary gear  21  provided on an inner side in the radial direction of the first carrier  19  at a side remote from the toroidal-type continuously variable transmission  1  (right sides of  FIGS. 7 through 8 ) meshes with a second sun gear  24  fixedly provided at a base end portion (left end portion of  FIG. 7 ) of transmitting shaft  6 . The remaining planetary gear  22  provided on an outer side in the radial direction of the first carrier  19  is made to be larger in an axial direction than the planetary gears  20 ,  21  provided on the inner side in an axial direction and meshes with the two gears  20 ,  21 . Further, the remaining planetary gear  22  and the first ring gear  23  are brought in mesh with each other.  
         [0013]     Meanwhile, a second carrier  25  for constituting the third planetary gear type transmission  4  is fixedly coupled to a base end portion (left end portion of  FIG. 7 ) of the output shaft  7 . Further, the second carrier  25  and the first ring gear  23  are coupled via a low speed clutch  26 . Further, a third sun gear  27  is fixedly provided to a portion proximate to a front side (proximate to right ends of  FIGS. 7 through 8 ) of the transmitting shaft  6 . Further, a second ring gear  28  is arranged at a surrounding of the third sun gear  27 . A high speed clutch  29  is provided between the second ring gear  28  and a fixed portion of the casing  15  or the like. A plurality of sets of planetary gears  30 ,  31  arranged between the second ring gear  28  and the third sun gear  27  are rotatably supported by the second carrier  25 . The respective planetary gears  30 ,  31  are brought in mesh with each other, the planetary gear  30  provided on an inner side in a radial direction of the second carrier  25  is brought in mesh with the third sun gear  27 , and the planetary gear  31  similarly provided on an outer side thereof is brought in mesh with the second ring gear  28 , respectively.  
         [0014]     In the case of the continuously variable transmission apparatus constituted as described above, power transmitted to the integral type output side disk  9  from the input shaft  5  via the input side disks  8   a ,  8   b  and the respective power rollers  10 ,  10  is outputted by way of the hollow rotating shaft  17 . Further, in a low speed mode of connecting the low speed clutch  26  and disconnecting the high speed clutch  29 , by changing transmission ratio of the toroidal-type continuously variable transmission  1 , a rotational speed of the output shaft  7  is made to be able to be converted regularly and reversely by interposing a stationary state while making a rotational speed of the input shaft  5  constant. That is, under the state, a differential component disposed between the first carrier  19  rotated in a regular direction along with the input shaft  5  and the first sun gear  18  rotated in a reverse direction along with the hollow rotating shaft  17  is transmitted from the first ring gear  23  to the output shaft  7  via the low speed clutch  26  and the second carrier  25 . Under the state, the output shaft  7  can be stopped by setting the transmission ratio of the toroidal-type continuously variable transmission  1  to a predetermined value, further the output shaft  7  can be rotated in a direction of moving back a vehicle by changing the transmission ratio of the toroidal-type continuously variable transmission  1  from the predetermined value to a speed increasing side. In contrast, the output shaft  7  can be rotated in a direction of moving forward the vehicle by changing the transmission ratio of the toroidal-type continuously variable transmission  1  from the predetermined value to a speed reducing side.  
         [0015]     Further, in a high speed mode of disconnecting the low speed clutch  26  and connecting the high speed clutch  29 , the output shaft  7  is rotated in the direction of moving forward the vehicle. That is, under the state, rotation of the planetary gear  20  of the first planetary gear type transmission  2  rotated in accordance with a differential component, which is disposed between the first carrier  19  rotated in a regular direction along with the input shaft  5  and the first sun gear  18  rotated in a reverse direction along with the hollow rotating shaft  17 , is transmitted to the planetary gear  21  of the second planetary gear type transmission  3  via the other planetary gear  22 , and the rotation of the planetary gear  20  rotate the transmitting shaft  6  via the second sun gear  24 . Further, the second carrier  25  and the output shaft  7  coupled with the second carrier  25  are rotated in a forward moving direction by meshing among the third sun gear  27  provided at the front end of the transmitting shaft  6 , the second ring gear  28  and the planetary gears  30 ,  31  constituting the third planetary gear type transmission  4  along with the sun gear  27 . Under the state, the more changed the transmission ratio of the toroidal-type continuously variable transmission  1  to the speed increasing side, the faster the rotational speed of the output shaft  7  can be made.  
         [0016]     When the toroidal-type continuously variable transmission is embodied including a case of constituting the continuously variable transmission apparatus by combining with the planetary transmission, it is necessary to monitor rotational speeds of respective portions for feeding back the rotational speeds to a controller for controlling the transmission ratio in order to monitor whether a desired transmission ratio is obtained. Particularly, in the case of the toroidal-type continuously variable transmission constituting the above-described continuously variable transmission apparatus, in connecting and disconnecting the two high speed and the low speed clutches  26 ,  29  for switching the low speed mode and the high speed mode, or in stopping the output shaft  7  while making the rotational speed of the input shaft  5  constant in the low speed mode, it is necessary to strictly restrict the transmission ratio of the toroidal-type continuously variable transmission  1 . Meanwhile, since a number of parts are present at an inner portion of the toroidal-type continuously variable transmission, a space for installing a part for detecting the rotational speed is limited. Therefore, it is preferable to be able to constitute a structure for detecting the rotational speeds of the respective portions of the toroidal-type continuously variable transmission as compact as possible.  
         [0017]     In view of such a situation, U.S. Pat. No. 6,099,431 describes a structure that recessed and projected portions for detecting the rotational speed are formed integrally with the input side shaft disk and on the outer peripheral portion of the input side disk. However, in U.S. Pat. No. 6,099,431, although a structure for detecting the rotational speed of the input side disk is described, there is not described a structure for detecting the rotational speed of the integral type output side disk, in which the both side faces in the axial direction are constituted by curved faces having a section in a circular arc shape for being respectively brought into rolling contact with peripheral faces of the power rollers. At a portion of installing such an integrated type output side disk, an extra space is small particularly at a surrounding thereof. Therefore, compact formation is requested for a structure for detecting the rotational speed of the output side disk more than that of the structure for detecting the rotational speed of the input side disk. In JP-A-11-141637, although there is described a structure formed with an output gear for outputting power at an outer peripheral edge portion of the integral type output side disk, it is not described to integrate a structure for detecting the rotational speed at the portion.  
       SUMMARY OF THE INVENTION  
       [0018]     In view of the above-described situation, an object of the present invention is to provide a compact structure for detecting a rotational speed of an integral type output side disk in which both side faces in an axial direction are constituted by curved faces having a section in a circular arc shape for respectively being brought into rolling contact with a peripheral face of the a power roller.  
         [0019]     According to a first aspect of the present invention, there is provided a toroidal-type continuously variable transmission, comprising: 
        a casing;     a rotation shaft rotatably supported in the casing;     a pair of outer side disks having side face of which section is in arc shape of the rotation shaft, respectively, supported on the rotation shaft at two positions which are separated from each other in the axial direction so that the side faces thereof oppose to each other, and rotating in synchronism with the rotation shaft;     an inner side disk having two side faces of which sections are in arc shape, rotatably supported on a substantially middle portion of the rotation shaft so that the both side faces thereof oppose to the side faces of the outer side disks, respectively, and rotating in the rotation shaft;     pluralities of supporting members disposed between the both side faces of the inner side disk and the side faces of the outer side disks, respectively, and swinging on a pivot shaft disposed to be twisted to the rotation shaft; and     pluralities of power rollers rotatably supported on the respective supporting members, and having spherical projected face of which peripheral surface rollably contacts with the both side faces of the inner side disk and the side faces of the outer side disks,     wherein an outer peripheral face of the inner side disk is provided with a detected portion for detecting rotation of the inner side disk.        
 
         [0027]     According to a second aspect of the present invention as set forth in the first aspect of the present invention, it is preferable that pluralities of recess portions are provided at a middle portion in the axial direction of the outer peripheral face intermittently in a circumferential direction as the detected portions.  
         [0028]     According to a third aspect of the present invention as set forth in the second aspect of the present invention, it is preferable that a portion of the outer peripheral face of the inner side disk deviated from the plurality of recess portions is a single cylindrical face, and the single cylindrical face is a reference face for working the both side faces of the inner side disk.  
         [0029]     According to a fourth aspect of the present invention as set forth in the first aspect of the present invention, it is preferable that pluralities of recess grooves are provided intermittently in a circumferential direction so as to be inclined to a center axis of the inner side disk as the detected portions.  
         [0030]     According to a fifth aspect of the present invention as set forth in the fourth aspect of the present invention, it is preferable that both end portions of pairs of projected portions, which are defined between the respective recess grooves provided at the outer peripheral face, overlap each other in the axial direction of the inner side disk, 
        top portions of the projected portions form a single cylindrical face when the inner side disk is viewed from the axial direction, and     the single cylindrical face is a reference face for working the both side faces the inner side disk.        
 
         [0033]     According to a sixth aspect of the present invention as set forth in the first aspect of the present invention, it is preferable that recess grooves are formed on an entire periphery of a middle portion in the axial direction of the outer peripheral face of the inner side disk, and 
        encoder elements are held in the recess groove, and the recess grooves and the encoder elements form the detected portion.        
 
         [0035]     According to a seventh aspect of the present invention as set forth in the sixth aspect of the present invention, it is preferable that portions of both end portions in the axial direction of the outer peripheral face of the inner side disk deviated from the recess groove are single cylindrical faces, and 
        the single cylindrical face is reference face for working the both side faces of the inner side disk.        
 
         [0037]     According to an eighth aspect of the present invention as set forth in the first aspect of the present invention, it is preferable that the toroidal-type continuously variable transmission further comprising: 
        a planetary gear type transmission having at least a carrier and a sun gear; and     a hollow rotation shaft,     wherein the rotation shaft functions as an input shaft,     the pair of outer side disks function as the input side disks,     the inner side disk functions as the output side disk,     the carrier couples the input shaft with one of the input side disks,     the sun gear is coupled with an end of the hollow rotation shaft, and     the hollow rotation shaft is disposed at surrounding of the input shaft so as to be concentric with the input shaft and coupled with the output side disk.        
 
         [0046]     According to a ninth aspect of the present invention as set forth in the second aspect of the present invention, it is preferable that the toroidal-type continuously variable transmission further comprising: 
        a planetary gear type transmission having at least a carrier and a sun gear; and     a hollow rotation shaft,     wherein the rotation shaft functions as an input shaft,     the pair of outer side disks function as the input side disks,     the inner side disk functions as the output side disk,     the carrier couples the input shaft with one of the input side disks,     the sun gear is coupled with an end of the hollow rotation shaft, and     the hollow rotation shaft is disposed at surrounding of the input shaft so as to be concentric with the input shaft and coupled with the output side disk.        
 
         [0055]     According to a tenth aspect of the present invention as set forth in the fourth aspect of the present invention, it is preferable that the toroidal-type continuously variable transmission further comprising: 
        a planetary gear type transmission having at least a carrier and a sun gear; and     a hollow rotation shaft,     wherein the rotation shaft functions as an input shaft,     the pair of outer side disks function as the input side disks,     the inner side disk functions as the output side disk, the carrier couples the input shaft with one of the input side disks,     the sun gear is coupled with an end of the hollow rotation shaft, and     the hollow rotation shaft is disposed at surrounding of the input shaft so as to be concentric with the input shaft and coupled with the output side disk.        
 
         [0063]     According to an eleventh aspect of the present invention as set forth in the sixth aspect of the present invention, it is preferable that the toroidal-type continuously variable transmission further comprising: 
        a planetary gear type transmission having at least a carrier and a sun gear; and     a hollow rotation shaft,     wherein the rotation shaft functions as an input shaft,     the pair of outer side disks function as the input side disks,     the inner side disk functions as the output side disk,     the carrier couples the input shaft with one of the input side disks,     the sun gear is coupled with an end of the hollow rotation shaft, and     the hollow rotation shaft is disposed at surrounding of the input shaft so as to be concentric with the input shaft and coupled with the output side disk.        
 
         [0072]     According to a twelfth aspect of the present invention as set forth in the first aspect of the present invention, it is preferable that at least a recessed portion is formed on the outer peripheral face of the inner disk as the detected portion.  
         [0073]     According to a thirteenth aspect of the present invention as set forth in the first aspect of the present invention, it is preferable that the recessed portions is formed on the substantially middle portion in the axial direction of the outer peripheral face of the inner side disk in a circumferential direction.  
         [0074]     According to a fourteenth aspect of the present invention as set forth in the first aspect of the present invention, it is preferable that pluralities of the recessed portions are formed on the outer peripheral face of the inner side disk so as to be inclined to the axial direction.  
         [0075]     According to a fifteenth aspect of the present invention as set forth in the first aspect of the present invention, it is preferable that the toroidal-type continuously variable transmission further comprising: 
        a detected element disposed in the recessed portion.        
 
         [0077]     In the case of the toroidal-type continuously variable transmission of the present invention constituted as described above, there can be realized a compact structure constituting integrated type output side disk having the both curved side faces in the axial direction, of which a section is in a circular arc shape, so that the both side faces rolling contacts with the peripheral face of the power roller for detecting a rotational speed of the output side disk. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0078]      FIG. 1  is a sectional view of an essential portion showing a first embodiment of the present invention;  
         [0079]      FIG. 2  is a sectional view showing a state of working a recess portion at the outer peripheral face of the output side disk;  
         [0080]      FIG. 3  is a sectional view of an essential portion showing a second embodiment of the present invention;  
         [0081]      FIG. 4  is a development view showing a state of an outer peripheral face of an output side disk from an outer diameter side;  
         [0082]      FIG. 5  is a sectional view of an essential portion showing a third embodiment of the present invention;  
         [0083]      FIG. 6  illustrates sectional views showing two examples of encoder elements;  
         [0084]      FIG. 7  is a sectional view showing an example of a continuously variable transmission apparatus integrated with a toroidal-type continuously variable transmission known in a related art; and  
         [0085]      FIG. 8  is a view enlarging a portion A of  FIG. 7 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0086]     In embodying the present invention, preferably, a plurality of recess portions are provided at a middle portion in the axial direction of an outer peripheral face of the inner side disk intermittently in a circumferential direction. Further, a portion of the outer peripheral face deviated from the respective recess portions is made to constitute a single cylindrical face constituting a reference face for working the both side faces in the axial direction of the inner side disk.  
         [0087]     Alternatively, the outer peripheral face of the inner side disk is provided with a plurality of recess grooves, respectively, which are inclined to a center axis of the inner side disk intermittently in the circumferential direction. Further, both end portions of pairs of projected portions for the respective recess grooves present by interposing the respective recess grooves are made to overlap each other in the axial direction of the inner side disk. Further, top portions of the respective projected portions constitute a single cylindrical face as a reference face for working the both side faces of the inner side disk when the inner side disk is viewed from the axial direction.  
         [0088]     Alternatively, recess grooves are formed over an entire periphery of a middle portion in the axial direction of an outer peripheral face of the inner side disk. Further, an encoder element having a detected portion is held in the recess groove. Further, portions of the both end portions in the axial direction of the outer peripheral face of the inner side disk deviated from the recess grooves are made to constitute a single cylindrical face constituting a reference face for working the both side faces in the axial direction of the inner side disk.  
         [0089]     When constituted in this way, the both side faces in the axial direction can be finished by ensuring the reference face in working the both side faces in the axial direction of the inner side disk while ensuring sufficient shape accuracy and dimensional accuracy without preparing an exclusive jig having a complicated shape.  
         [0090]     Further, in embodying the present invention, preferably, the rotating shaft is made to constitute an input shaft, the pair of outer side disks are respectively made to constitute input side disks, and the input shaft and one of the input side disks are coupled via a carrier constituting the planetary gear type transmission. Further, the inner side disk is made to constitute an output side disk, and a sun gear constituting the planetary gear type transmission is provided at other end portion of a hollow rotating shaft arranged concentrically with the input shaft at a surrounding of the input shaft and coupled with one end portion of the output side disk.  
         [0091]     In such a structure, whereas a space of installing a part for detecting the rotational speed of the output side disk is limited, there is increased a necessity of measuring a rotational speed of the output side disk in order to strictly control the transmission ratio of the toroidal-type continuously variable transmission. Therefore, a significance of embodying the present invention by the above-described structure is enhanced.  
       First Embodiment  
       [0092]      FIGS. 1 through 2  show first embodiment of the present invention. A characteristic of the embodiment resides in that pluralities of recess portions  32 ,  32  are provided at a center portion in an axial direction of an outer peripheral face  34  of an output side disk  9   a  intermittently and at equal intervals in a circumferential direction in order to detect a rotational speed of the output side disk  9   a  constituting an inner disk. A structure of a toroidal-type continuously variable transmission integrated with the output side disk  9   a  and a structure of a continuously variable transmission apparatus integrated with the toroidal-type continuously variable transmission are similar to the structures of the related art illustrated in  FIGS. 7 through 8  and therefore, an illustration as well as a detailed explanation thereof will be omitted or simplified and an explanation will be given of a characteristic portion of the present invention as follows.  
         [0093]     Both end portions in the axial direction of the output side disk  9   a  are rotatably supported by the holding rings  16 ,  16  by the pair of thrust angular ball bearings  11 ,  11 . A rotational force is made to be able to be outputted by the hollow rotating shaft  17  engaged with the inner peripheral face by a spline. A plurality (60 portions in the illustrated example) of recess portions  32 ,  32  are provided at the center portion in the axial direction of the outer peripheral face  34  of the output side disk  9   a  intermittently in the circumferential direction with having equal intervals. Each of the respective recess portions  32 ,  32  is a bottomed circular hole formed by drills  33 ,  33 . Further, an outer diameter d of each of the drills  33 ,  33  is sufficiently smaller than a width w of the outer peripheral face  34  of the output side disk  9   a  (d&lt;&lt;w). Therefore, a large portion of the outer peripheral face  34  of the output side disk  9   a  constitutes a single cylindrical face. Particularly, both end portions in the axial direction thereof constitutes a cylindrical face continuous over an entire periphery thereof.  
         [0094]     In a state of integrating the above-described output side disk  9   a  to the toroidal type continuously variable transmission, a detecting face of a rotation detecting sensor (not illustrated) of a magnetic type, an electrostatic capacitance type, or an eddy current type fixedly supported in the casing is made to be opposed to the center portion in the axial direction of the outer peripheral face of the output side disk  9   a . Since the output side disk  9   a  is made of bearing steel or the like, which is a metal having magnetism and conductivity properties, various characteristics such as the magnetic property, an electrostatic capacitance property or the like of the center portion in the axial direction of the outer peripheral face  34  of the output side disk  9   a  are changed in turn in the circumferential direction at equal intervals. Therefore, by selecting the rotation detecting sensor having a pertinent structure, the rotational speed of the output side disk  9   a  can accurately be provided.  
         [0095]     since both side faces  35 ,  35  in the axial direction of the output side disk  9   a  are faces of transmitting power by being brought into rolling contact with peripheral faces of the power rollers  10 ,  10  (refer to  FIGS. 7 through 8 ), it is necessary not only to accurately restrict shape accuracy and dimensional accuracy but also to reduce surface roughness, in other word, it is necessary to obtain smooth faces. Therefore, in order to provide the output side disk  9   a  having excellent quality, it is important to select reference faces for finishing the both side faces  35 ,  35  in the axial direction. According to the embodiment of the present invention, a large portion of the outer peripheral face  34  of the output side disk  9   a  constitutes a single cylindrical face, particularly, the both end portions in the axial direction constitute the cylindrical faces continuous over the entire peripheries. Therefore, when the outer peripheral face  34  is properly worked before finishing the both side faces  35 ,  35  and the two side faces  35 ,  35  are finished by constituting a reference face by the outer peripheral face, shape accuracy, dimensional accuracy and surface roughness of the two side faces  35 ,  35  can be made to be proper.  
         [0096]     A method of working the respective recess portions  32 ,  32  is not particularly limited. For example, in the case of forming the 60 portions of the respective recess portions  32 ,  32 , the respective recess portions  32 ,  32  can be formed by a drilling press having a single piece of a drill and having a dividing angle of 6 degrees. Or, the 60 portions of the recess portions  32 ,  32  can also be formed in one motion by a working apparatus radially arranged with 60 pieces of drills. However, when working is carried out by the single piece drill, a working time period is prolonged. Alternatively, in the case of the working apparatus having 60 pieces of drills, the structure is complicated and the working apparatus becomes expensive.  
         [0097]     In view of the above situation, in the case of the embodiment, the 60 portions of the recess portions  32 ,  32  are formed by a working apparatus radially arranged with 20 pieces of the drills  33 ,  33  at equal intervals (by a pitch of 18 degrees) and realizing a dividing angle of 6 degrees. According to the working apparatus, the 60 pieces of the recess portions  32 ,  32  can be formed by carrying out working by 3 times while rotating the output side disk  9   a  by 6 degrees. Therefore, it can be prevented that cost of the working apparatus is uselessly increased, or a working time period of the respective recess portions  32 ,  32  are uselessly prolonged.  
         [0098]     Further, the respective recess portions  32 ,  32  can also be produced simultaneously (by plastic working) when a gross shape of the output side disk  9   a  is provided by applying plastic working of single motion working or the like to a material.  
       Second Embodiment  
       [0099]      FIGS. 3 through 4  show second embodiment of the present invention. In the case of the embodiment, an outer peripheral face of an output side disk  9   b  constituting the inner side disk is provided with a plurality of recess grooves  36 ,  36  respectively inclined to the center axis of the output side disk  9   b  intermittently in the circumferential direction. In a state of integrating the above-described output side disk  9   b  to the toroidal-type continuously variable transmission, when the detecting face of the rotation detecting sensor (not illustrated) is made to be opposed to some portion of the outer peripheral face of the output side disk  9   b  (different from first embodiment, the portion is not limited to the center portion in the axial direction), the rotational speed of the output side disk  9   a  can accurately be provided.  
         [0100]     Further, in the case of the embodiment, an inclination angle θ of the respective recess grooves  36 ,  36  is increased to some degree, both end portions of pairs of projected portions  37 ,  37  present by interposing the respective recess grooves  36 ,  36 , represented by a dotted pattern area in  FIG. 4  at the respective recess grooves  36 ,  36  are made to overlap each other by an amount of Δ 37  of  FIG. 4  in the axial direction of the output side disk  9   b . Therefore, when the output side disk  9   b  is viewed from the axial direction (side directions of  FIGS. 3 through 4 ), top portions of the respective projected portions  37 ,  37  constitute a single cylindrical face. That is, when the output side disk  9   a  is viewed from side directions of  FIGS. 3 through 4 , the outer peripheral shape becomes a regular circle which is not recessed over the entire periphery. Therefore, by using the top portions of the respective recess portions  37 ,  37  as a reference face for working the both side faces  35 ,  35  of the output side disk  9   a , when the both side faces  35 ,  35  are finished, shape accuracy, dimensional accuracy and surface roughness of the both side faces  35 ,  35  can be made to be proper.  
         [0101]     Further, although shapes of the respective recess grooves  36 ,  36  and the respective projected portions  37 ,  37  may be an involute shape, the shapes may be a shape of a simple rectangular groove or a circular arc groove shape since power is not transmitted particularly. However, since large force is exerted to the output side disk  9   b  in operating the toroidal-type continuously variable transmission, it is preferable that a portion having a small radius of curvature is not present at bottom portions of the respective recess grooves  36 ,  36  such that stress is not concentrated to the bottom portions of the respective recess grooves  36 ,  36 . Therefore, it is preferable to constitute the respective recess grooves  36 ,  36  by a section in a circular arc shape.  
       Third Embodiment  
       [0102]      FIGS. 5 through 6  show third embodiment of the present invention. In the case of the embodiment, a recess groove  38  is formed over an entire periphery at a center portion in an axial direction of an outer peripheral face of an output side disk  9   c  constituting the inner side disk. Further, an encoder element  39  in ring shape having a detected portion is held in the recess groove  38 . The encoder elements  39  having various structures can be used so far as the characteristics are changed alternately and at equal intervals in the circumferential direction in order to be able to detect the rotational speed by being combined with a rotation detecting sensor, not illustrated. For example, when combined with a rotation detecting sensor of a magnetism detecting type, an encoder element  39   a  formed with a magnetic metal material in a wavy shape as shown in  FIG. 6A , or an encoder element  39   b  formed with a number of through holes as shown in  FIG. 6B  can be used. Or, although not illustrated, an encoder element made by a permanent magnet arranged with S poles and N poles alternately and at equal intervals at an outer peripheral face thereof can also be used. In cases of adopting any structures, in a state before being held in the recess groove  38 , a portion of the encoder element  39  in the circumferential direction is made to be discontinuous and a diameter of the encoder element  39  is made to be able to be widened. The discontinuous portion is bonded by welding or adhering after having been held in the recess groove  38 .  
         [0103]     Also in the case of the embodiment, in a state of integrating the output side disk  9   c  holding the above-described encoder element  39  to the toroidal-type continuously variable transmission, when a detecting face of a rotation detecting sensor (not illustrated) is made to be opposed to the outer peripheral face of encoder element  39 , the rotational speed of the output side disk  9   c  can accurately be provided. Further, in the case of the embodiment, when both side portions of the recess groove  38  are used as reference faces for working the both side faces  35 ,  35  of the output side disk  9   c  and the both side faces  35 ,  35  are finished, shape accuracy, dimensional accuracy and surface roughness of the both side faces  35 ,  35  can be made to be proper.  
         [0104]     While there has been described in connection with the preferred embodiments of the present invention, it will be obvious to those skilled in the art that various changes and modification may be made therein without departing from the present 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 present invention.