JP4461794B2 - Toroidal continuously variable transmission - Google Patents

Description

  The present invention relates to an improvement in a toroidal continuously variable transmission that can be used, for example, as a transmission unit for an automatic transmission of an automobile or as a transmission for various industrial machines.

  The use of toroidal continuously variable transmissions as automatic transmissions for automobiles has been studied and implemented in part. This toroidal continuously variable transmission has a configuration as described in Patent Document 1, for example. 1 and 2 schematically show the basic configuration of the toroidal-type continuously variable transmission. In the structure shown in FIGS. 1 and 2, the input side disk 2 is supported concentrically with the input shaft 1, and the output side disk 4 is fixed to the end of the output shaft 3 disposed concentrically with the input shaft 1. Yes. Further, inside the casing (not shown) in which the toroidal-type continuously variable transmission is housed, trunnions 6 and 6 swinging around the pivot shafts 5 and 5 that are twisted with respect to the input shaft 1 and the output shaft 3 are provided. Provided.

  Each trunnion 6, 6 has the pair of pivots 5, 5 concentric with each other for each trunnion 6, 6 on both ends in the length direction (front and back direction in FIGS. 1 and 2). It is provided one by one. The central axes of the pivots 5 and 5 do not intersect with the central axes of the disks 2 and 4 but are twisted at right angles or substantially perpendicular to the direction of the central axes of the disks 2 and 4. Exists in the position. Further, the base half of the support shafts 7 and 7 is supported at the center of the trunnions 6 and 6, and the trunnions 6 and 6 are swung around the pivots 5 and 5 so that the support shafts are supported. 7 and 7 can be adjusted freely. Power rollers 8 and 8 are rotatably supported around the front half portions of the support shafts 7 and 7 supported by the trunnions 6 and 6, respectively. These power rollers 8 and 8 are sandwiched between the side surfaces 2a and 4a of the input side and output side disks 2 and 4, respectively.

  The side surfaces 2a and 4a of the input side and output side disks 2 and 4 facing each other are cross-sectional circles obtained by rotating a cross section of an arc centered on the pivot 5 or a curve close to such an arc. It has an arcuate concave surface. And the peripheral surfaces 8a and 8a of each power roller 8 and 8 formed in the spherical convex surface are made to contact | abut to the said side surfaces 2a and 4a. Also, a loading cam device 9 is provided between the input shaft 1 and the input side disk 2, and the input side disk 2 is pressed against the output side disk 4 by the loading cam device 9, and can be rotationally driven. It is said.

  When the toroidal continuously variable transmission configured as described above is used, the loading cam device 9 presses the input side disk 2 against the plurality of power rollers 8 and 8 as the input shaft 1 rotates. Rotate. The rotation of the input side disk 2 is transmitted to the output side disk 4 via the plurality of power rollers 8, 8, and the output shaft 3 fixed to the output side disk 4 rotates.

  When the rotational speeds of the input shaft 1 and the output shaft 3 are changed and when the deceleration is first performed between the input shaft 1 and the output shaft 3, the trunnions 6 and 6 are swung around the pivot shafts 5 and 5. As shown in FIG. 1, the peripheral surfaces 8a and 8a of the power rollers 8 and 8 are respectively formed on a portion near the center of the side surface 2a of the input side disk 2 and a portion near the outer periphery of the side surface 4a of the output side disk 4 respectively. The support shafts 7 and 7 are inclined so as to contact each other. On the contrary, when the speed is increased, the trunnions 6 are swung, and the peripheral surfaces 8a and 8a of the power rollers 8 and 8 are side surfaces 2a of the input side disk 2 as shown in FIG. The support shafts 7 and 7 are inclined so as to abut the outer peripheral portion and the central portion of the side surface 4a of the output disk 4 respectively. If the inclination angles of the support shafts 7 and 7 are set in the middle between those shown in FIGS. 1 and 2, an intermediate gear ratio can be obtained between the input shaft 1 and the output shaft 3. The toroidal type continuously variable transmission shown in FIGS. 1 and 2 is a so-called single cavity type in which one input side disk 2 and one output side disk 4 are provided. On the other hand, a structure in which two input-side disks and two output-side disks are provided in parallel with each other in the power transmission direction is also described in many documents such as Patent Documents 2 to 6 and is conventionally known. Yes.

  During operation of the toroidal continuously variable transmission constructed and operated as described above, rolling contact portions (traction) between the side surfaces 2a, 4a of the disks 2, 4 and the peripheral surfaces 8a, 8a of the power rollers 8, 8 Part) is provided with an oil film of traction oil. This traction oil has the role of transmitting power in this traction part, and also has the role of lubricating moving parts such as rolling bearings, so it is made of hard metal such as burrs and wear powder that has separated from the constituent members. It is inevitable that foreign matter gets mixed in. The presence of such foreign matters causes the rolling fatigue life of the surfaces 2a, 4a and 8a constituting the traction portion to be reduced. For this reason, in order to ensure the rolling fatigue life of each of the surfaces 2a, 4a, 8a even when traction oil mixed with foreign matter is used, the two disks 2, 4 and the power rollers 8, 8 have been conventionally used. The amount of retained austenite on the surface is increased. In order to increase the amount of retained austenite, carburizing treatment and carbonitriding treatment, which are heat treatments conventionally performed in fields other than toroidal-type continuously variable transmissions, are performed on each of the members 2, 4, 8. It was also used for surface treatment. For example, Patent Documents 7 and 8 disclose that these members are subjected to such heat treatment.

  In any toroidal-type continuously variable transmission having any structure, an output gear that rotates with the output side disk is provided in order to extract the power transmitted from the input side disk to the output side disk via the power roller. In many cases, a structure is employed in which the output gear and the gear of the rotation transmission mechanism are engaged with each other. In this case, if the output gear and the output disk 4 are separated, the length in the axial direction of the combined structure of the output gear and the output disk 4 is increased. Improvement is desired when considering miniaturization and weight reduction. For this reason, in the case of the structures described in Patent Documents 2 to 6, an annular output side gear is attached to the outer peripheral edge of the output side disk by welding (Patent Document 3) or by external fitting and adhesion (Patent Document). 5) It is fixed or directly formed on the output side disk itself (Patent Documents 2, 4, and 6). Among these, as described in Patent Documents 3 and 5, in the case of a structure in which the separate output side disk and the output gear are coupled and fixed, the properties of each part including the hardness may be made appropriate. Although it is easy, the manufacturing process becomes complicated and the cost tends to increase. In addition, as a result of externally fitting a separate gear to the disc, the diameter of the portion that makes rolling contact with the peripheral surface of the power roller is secured on the side surface in the axial direction of the output side disc in order to ensure the transmission ratio of the toroidal type continuously variable transmission If an attempt is made, the overall outer diameter will increase, leading to an increase in the size and weight of the toroidal continuously variable transmission. If it is attempted to reduce the thickness in the radial direction of the gear to prevent an increase in size and weight, the manufacturing process becomes more complicated, such as an extra step being required to correct the heat treatment deformation. On the other hand, as described in Patent Documents 2, 4, and 6, in the case of the structure in which the output gear is directly formed on the output side disk itself, the manufacturing process is simplified while reducing the size and weight. This makes it easier to reduce costs.

  3 to 4 show the structure described in Patent Document 6 among the structures in which the output gear is directly formed on the output side disk itself. FIG. 3 shows a single-cavity toroidal continuously variable transmission in which an output gear 10 is directly formed on the outer peripheral edge of the output-side disk 4. FIG. 4 shows a toroidal type continuously variable transmission of a double cavity type, in which an output gear 10 is directly formed on the outer peripheral edge of the output side disk 4A. In the output side disk 4A, both side surfaces 4a and 4a are concave surfaces having a circular arc cross section for rolling contact with the peripheral surfaces 8a and 8a (see FIGS. 1 to 3) of the power rollers 8 and 8, respectively. Such an output-side disk 4A supports the relative rotation with respect to the input shaft 1A freely around the intermediate portion of the input shaft 1A. In addition, a pair of input side disks 2 and 2 at both ends of the input shaft 1A can be rotated in synchronization with the input shaft 1A, and side surfaces 2a and 2a having an arcuate cross section are formed on the output side disk 4A. The respective side surfaces 4a and 4a are supported in a state of being opposed to each other. The structure and operation of the toroidal-type continuously variable transmission as shown in FIGS. 3 and 4 are described in Patent Document 6 and are not related to the gist of the present invention.

As shown in FIGS. 3 and 4 described above, even in the case of the output side disks 4 and 4A in which the output gear 10 is directly formed on the outer peripheral edge, the surfaces that are in rolling contact with the peripheral surfaces 8a and 8a of the power rollers 8 and 8 In order to secure a rolling fatigue life, it is necessary to increase the amount of retained austenite on the surface and increase the hardness. On the other hand, it is not preferable that the surface of the output gear 10 is so hard that it is in contact with the rolling contact in order to ensure toughness. In response to such a requirement, Patent Document 4 describes the following method for producing an output side disk in which an output gear is directly formed on the outer peripheral edge.
(1) After the disk and gear are integrally formed, the gear face is processed after carburizing or carbonitriding, and then carburizing quenching or carbonitriding quenching is performed, and finally finishing is performed.
(2) In the above (1), the gear portion is subjected to a carburizing treatment, and then the first carburizing treatment or carbonitriding treatment is performed.
(3) After pre-processing, the gear part is subjected to semi-carburization treatment, carburization quenching treatment or carbonitriding quenching treatment treatment, and finally finishing.
(4) After pre-processing, the gear portion and the axial side surface in contact with the power roller are subjected to induction hardening under different conditions, and finally finish processing is performed.

  Among the manufacturing methods described in Patent Document 4, in the case of the manufacturing method (1), after the carburizing process or carbonitriding process, the gear surface is processed with the surface hardened. The processing becomes complicated and the processing cost increases. In the case of the production methods (2) and (3), since the gear portion is subjected to a carbon-proof treatment, the following problems arise instead of facilitating the processing of the gear portion. That is, it is difficult to make the application state of the anti-carburizing agent uniform, and it is difficult to obtain a stable effect. In addition, when the anti-carburizing agent passes and adheres to the axial side surface portion that is in rolling contact with the power roller, the hardness of the portion becomes insufficient, and the rolling fatigue life of this portion is reduced. Also, as in the manufacturing method of (4), when induction hardening is performed under different conditions for the gear part and the axial side surface that is in rolling contact with the power roller after pre-processing, it can be processed in a short time. Although there is an advantage, the amount of retained austenite on the side surface in the axial direction becomes insufficient, and the durability of the disk may not be sufficiently secured.

JP 2003-222216 A JP-A-8-159229 JP 11-63139 A Japanese Patent Laid-Open No. 11-141537 JP 2002-139118 A JP 2003-301908 A JP-A-9-79337 JP-A-10-103440

  In view of the circumstances as described above, the present invention realizes a toroidal continuously variable transmission equipped with a disk that can secure a sufficient rolling fatigue life and can be manufactured at low cost even when using traction oil mixed with foreign matter. Invented as much as possible.

  Each of the toroidal type continuously variable transmissions subject to the present invention is made of steel on the axial side surfaces of the first and second discs each made of steel, each of which is a concave surface having an arcuate cross section. It has a structure in which power is transmitted between both disks by bringing the partial spherical peripheral surfaces of a plurality of power rollers into rolling contact with each other via an oil film of traction oil. A power transmission gear is directly formed on the outer peripheral edge of at least one of the two disks.

  In particular, in the toroidal-type continuously variable transmission according to claim 1, the disk on which the gear is formed is tempered after carburizing treatment or carbonitriding treatment for surface hardening, and then the power rollers. It is made by induction-hardening the axial side surface portion that is in rolling contact with the peripheral surface and the gear portion.

  Further, in the toroidal type continuously variable transmission according to claim 2, the disk on which the gear is formed is allowed to cool after carburizing treatment or carbonitriding treatment for surface hardening, and then the power rollers. It is made by induction-hardening the axial side surface portion that is in rolling contact with the peripheral surface and the gear portion.

  Further, in the toroidal type continuously variable transmission according to claim 3, the disk on which the gear is formed is allowed to cool after carburizing treatment or carbonitriding treatment for surface hardening, and further subjected to tempering. From the above, it is made by subjecting the axial side surface portion that is in rolling contact with the peripheral surface of each power roller and the gear portion to induction hardening. Note that the above-mentioned cooling is different from the rapid cooling for quenching, and refers to a process (gradual cooling) that is left as it is in the furnace or in the atmosphere in order to gradually lower the temperature of the carburizing process or the carbonitriding process. .

  Further, in the toroidal-type continuously variable transmission according to claim 4, the disk on which the gear is formed includes the gear portion after carburizing or carbonitriding for surface hardening. A portion that does not require hardness compared to the axial side surface that is in rolling contact with the peripheral surface is partially tempered, and then the axial side surface and the gear portion are subjected to induction hardening.

  Further, in the toroidal type continuously variable transmission according to claim 5, the disk on which the gear is formed is allowed to cool after carburizing treatment or carbonitriding treatment for surface hardening, and then the gear portion is removed. In addition, partial tempering was performed on a portion that does not require hardness compared to the axial side surface that is in rolling contact with the peripheral surface of each power roller, and then the axial side surface and the gear portion were subjected to induction hardening. Is.

  Further, in the toroidal type continuously variable transmission according to claim 6, the disk on which the gear is formed includes the gear portion after carburizing treatment or carbonitriding treatment for surface hardening. A portion that does not require hardness compared to the axial side surface that is in rolling contact with the peripheral surface is subjected to partial tempering, and then the gear portion is subjected to induction hardening.

As described above, in the case of the toroidal continuously variable transmission and the manufacturing method thereof according to the present invention, a sufficient rolling fatigue life can be secured even when traction oil mixed with foreign matter is used, and power is transmitted to the outer periphery. A toroidal-type continuously variable transmission incorporating a disc equipped with a gear can be realized at low cost.
First, since the hardened layer is formed on the surface of the disk by performing carburizing or carbonitriding on the disk, the amount of retained austenite on the surface of the disk is increased, and the above-mentioned in the presence of minute foreign matter is performed. The rolling fatigue life of the member can be secured.

Further, since the processing of the gear portion at the outer peripheral edge of the disk can be performed in a state where the hardness of the outer peripheral edge is low, the processing of the gear portion is easy, and the disk is accompanied with the processing of the gear portion. As a result, the cost of the toroidal-type continuously variable transmission incorporating this disk can be prevented from increasing. Moreover, the toughness of the gear portion can be ensured, and damage such as chipping or cracking can be prevented from occurring in the gear portion.
That is, in any case, the basic shape of the gear portion is processed before the carburizing process or the carbonitriding process for surface hardening, so that this processing operation can be easily performed. Preferably, the finishing of the gear portion is performed after the carburizing or carbonitriding process in order to remove the distortion associated with the carburizing or carbonitriding process, but even in this case, the finishing process is performed in an extremely hard state. There is no need to apply. For this reason, processing work is easy and it is difficult to increase the cost.

  The amount of retained austenite on one side of the disk in the axial direction, which is in rolling contact with the outer peripheral surface of the power roller, is determined from the surface that ensures the durability of this one side of the axial direction when traction oil is used. It is preferable to restrict to 20 to 45% by volume. When the amount of retained austenite in this portion is smaller than this, it is difficult to ensure the durability of the portion when the amount of foreign matter in the traction oil is large. On the other hand, if the amount of retained austenite in this portion is too large, problems such as difficulty in ensuring dimensional accuracy may occur. In the case of the invention described in any claim, induction hardening is performed after carburizing treatment or carbonitriding treatment for surface hardening. Therefore, when carrying out the invention described in any claim, preferably, the carburizing treatment or carbonitriding so that the retained austenite amount in the above range can be secured in the state after the induction hardening. Select the surface carbon concentration and surface nitrogen concentration during processing.

  Also, the carbon and / or nitrogen diffused on the surface of the disk based on this carburizing or carbonitriding process is at least deep enough to obtain a sufficient hardened layer depth by induction hardening performed later. Heat treatment conditions (treatment temperature, treatment time, heat treatment atmosphere such as carbon potential value and ammonia flow rate) are selected so as to diffuse. In addition, the carbonitriding treatment tends to reduce the particle size of the carbide produced on the surface portion compared to the carburizing treatment, and the smaller the particle size of the carbide, the larger the cause of cracking and chipping. Advantageous eutectic carbide is difficult to precipitate. Therefore, it is preferable to perform the carbonitriding process rather than the carburizing process. In addition, the induction hardening performed after the carburizing treatment or the carbonitriding treatment is much shorter (for example, about 10 seconds) as compared with the continuous quenching, and it is not possible to secure the time for the carbide to dissolve in the matrix. For this reason, the amount of retained austenite tends to decrease with induction hardening, and in some cases, the amount of retained austenite in the above range may not be ensured after induction hardening. For this reason, it is preferable to perform a carbonitriding treatment capable of reducing the precipitated carbide relatively, since the amount of retained austenite after induction hardening tends to increase.

  Further, after completion of the carburizing treatment or carbonitriding treatment, it is preferable to perform tempering as in the invention described in claim 1. The reason for this is to prevent the occurrence of damage due to delayed fracture or the like in the gear portion formed in the outer peripheral edge portion. In other words, depending on the cooling conditions after carburizing or carbonitriding, as in the above gear part, less hardness is required, and if the hardness becomes higher than necessary, even the part where delayed fracture is a concern, In order to make rolling contact with the peripheral surface of the roller, it may be hardened to the same extent as the axial side surface that requires particularly high hardness. In particular, if the entire gear portion is hardened more than necessary, tooth breakage may occur when an impact load is applied. In the case of the invention described in claim 1, in order to prevent such breakage, tempering is performed after carburizing or carbonitriding, and the hardness of the entire disk including the gear portion and the axial side surface is reduced. Let me. As a result of the tempering, the hardness of the entire disk is lowered, so that the required hardness is ensured by induction hardening. Conditioning and induction hardening conditions are determined in consideration of the required hardness. In this case, since the required hardness differs between the gear portion and the axial side surface, the induction hardening conditions are different from each other.

  Further, to prevent the gear portion from being damaged due to delayed fracture or the like, the cooling after the carburizing treatment or carbonitriding treatment can be allowed to cool as in the invention described in claim 2. realizable. This cooling is performed, for example, by leaving the disk in a heating furnace after carburizing or carbonitriding and gradually lowering the temperature in the heating furnace. In this way, if the cooling rate after carburizing or carbonitriding is reduced (if it is slowed down), the disk will not be hardened, and high hardness parts will not be hardened more than necessary. . In this case, if the hardness of the disk surface can be properly controlled by appropriately controlling the cooling rate, induction hardening may be performed immediately after cooling without performing tempering. However, when cooling after heat treatment such as carburizing treatment or carbonitriding treatment, variation depending on the location may appear regardless of whether the cooling location is inside or outside the furnace. In this case, as in the invention described in claim 3, the hardness can be surely adjusted by applying tempering after cooling.

Further, in order to prevent the gear portion from being damaged due to delayed fracture or the like, hardness is required after carburizing treatment or carbonitriding treatment as in the invention described in claim 4 instead of tempering. It can also be achieved by partial tempering the parts that are not. For partial tempering performed in this case, a method using high frequency induction heating, a method using flame, a method using laser heating, or the like can be employed. Regardless of which method is employed, in this way, it is possible to shorten the time required to reduce the hardness of the portion that does not require the above-mentioned hardness. In this case, as in the invention described in claim 5, if the part that does not require the above hardness is subjected to partial tempering after being allowed to cool after carburizing or carbonitriding, the hardness can be adjusted more reliably. Yes. In any case, after partial tempering, induction hardening is performed on the axial side surface and the gear portion, and the hardness of each portion is set to a necessary value.
The conditions of induction hardening performed to cure these axial side surfaces and gear portions are regulated from the surface that makes the surface hardness and effective hardened layer depth of these portions appropriate. In addition, tempering is performed after induction hardening.

  Further, to prevent the gear portion from being damaged due to delayed fracture or the like, as in the invention described in claim 6, quenching is performed after carburizing treatment or carbonitriding treatment. It can also be realized by performing partial tempering on a portion that does not require hardness as compared with the axial side surface in rolling contact with the peripheral surface of the power roller. The gear portion of this portion is subjected to induction hardening after tempering to ensure the required hardness. In carrying out the invention described in claim 6, it is necessary to impart the required surface hardness and hardness distribution to the axial side surface portion in the carburizing or carbonitriding process. It becomes. Then, partial tempering is performed only on the parts that do not require hardness such as the gear part to reduce the hardness, and only the gear part is induction hardened to give the gear part the necessary hardness. Even in this way, a long-life disk can be obtained at low cost.

  Further, preferably, when the present invention is carried out, as in the invention described in claim 7, if carbon steel containing 0.5 to 1.2% by weight of C is used as the steel material constituting the disk, The cost of the disk can be further reduced. In the case of the invention described in claims 1 to 5, induction hardening is performed after the carburizing process or the carbonitriding process. In this case, in order to obtain an appropriate hardness distribution after induction quenching, the carbon corresponding to the hardened layer depth required on the side surface in the axial direction of the completed disk at the time when the carburizing process or carbonitriding process is completed. It is necessary to set the concentration distribution and the nitrogen concentration distribution. If the amount of carbon contained in the steel material is 0.5% by weight or more, it is required on the side surface in the axial direction of the completed disc even without carburizing or carbonitriding, or only by induction hardening. An effective hardened layer depth can be obtained. Accordingly, if a steel material having a C content of 0.5% by weight or more is used, the carburizing treatment and the carbonitriding treatment are the minimum amount of retained austenite required for the axial side surface and the depth thereof. What is necessary is just to carry out on the conditions which can obtain carbon concentration and / or nitrogen concentration. As a result, the time required for carburizing or carbonitriding can be greatly reduced.

However, if the C content exceeds 1.2% by weight, the grain size of the carbide in the material becomes large, and it becomes difficult to obtain sufficient hardness and the amount of retained austenite by induction hardening. Therefore, the C content is 1.2% by weight or less.
Even when the carbon steel containing 0.5 to 1.2% by weight of C as the steel material constituting the disk is applied to the invention described in claim 6, the time required for carburizing or carbonitriding Can be greatly shortened.

FIG. 5 shows Embodiment 1 of the present invention corresponding to claims 1 to 3. In the case of the present embodiment, in the following first to fourth steps, the side surfaces 4a and 4a in the axial direction are concave surfaces having an arcuate cross section that makes the peripheral surface of the power roller roll and contact, and the output gear 10 is provided on the outer peripheral edge. The formed output side disk 4A is obtained.
First Step A first intermediate material 11 having a shape as shown in FIG. 5A is obtained by subjecting a carbon steel material to cutting or forging. In this state, gear cutting of the output gear 10 formed on the outer peripheral edge portion is performed.

Second Step Carburizing or carbonitriding is performed on the first intermediate material 11 to obtain a second intermediate material 13 having a hardened layer 12 formed on the entire surface, as shown in FIG. Preferably, in such a state that the second step is completed, a gradient of carbon concentration and / or nitrogen concentration is obtained to such an extent that a predetermined effective hardened layer depth can be obtained after induction hardening performed later. Also preferably, a surface carbon concentration and / or a nitrogen concentration is obtained such that the amount of retained austenite after induction hardening is 20 to 45% by volume in the state at the completion of the second step. In addition, if the carbon concentration in the said raw material is 0.5 weight% or more, the time which a carburizing process or a carbonitriding process requires can be shortened.

Third Step When the invention described in claim 1 is carried out, in this third step, a third intermediate is carried out by tempering in order to reduce the hardness of the portion where delayed fracture is a concern. Get material (not shown). This tempering is also necessary to ensure the toughness of the output gear 10. That is, if the output gear 10 is quenched and hardened over the entire surface, tooth breakage may occur when an impact load is applied, so the hardness of the output gear 10 portion is also reduced. To ensure toughness. The temperature of the above tempering is determined in consideration of such points. It should be noted that the tempering is preferably performed at 450 ° C. or higher in consideration of the fact that temper brittleness may appear depending on the tempering temperature for tempering. However, if the tempering temperature is too high, the spheroidization of the carbide proceeds and the induction hardenability may be lowered. Therefore, the tempering temperature is preferably suppressed to 700 ° C. or lower.
In carrying out the invention described in claim 2, in the third step, the cooling after the carburizing process or the carbonitriding process is performed by cooling (slow cooling). If the cooling rate after the carburizing or carbonitriding process is reduced, the third intermediate material is not hardened by hardening. In order to secure the toughness without quenching and hardening, that is, to ensure the toughness without quenching and hardening, the third intermediate material after carburizing or carbonitriding is left in the furnace to ensure sufficient cooling time. Is preferred.
Furthermore, when the invention described in claim 3 is carried out, the hardness of the third intermediate material is more reliably adjusted by further tempering after cooling in this third step.

Fourth Step In this fourth step, induction hardening is applied to the axially opposite side surface portions of the third intermediate material and the output gear 10 portion of the outer peripheral edge, and appropriate hardness is imparted to these portions, As shown in FIG. 5C, an output side disk 4A which is a finished product is obtained. The induction hardening is performed on at least the axial side surfaces 4a and 4a and the output gear 10 portion. These axially opposite side surfaces 4a and 4a and the output gear 10 portion have different required hardened layer depths, so that the induction heating conditions for induction hardening are also different from each other. Quenching may be performed with oil or water. Moreover, induction hardening can also be performed on portions other than the axial side surfaces 4a and 4a and the output gear 10 as required. In any part, after induction hardening, tempering is performed, and then necessary finishing is performed to obtain the output side disk 4A.

FIG. 6 shows a second embodiment of the present invention corresponding to claims 4 and 5. Also in the case of the present embodiment, in the following first to fourth steps, both axial side surfaces 4a and 4a are concave surfaces having an arcuate cross section that causes the peripheral surface of the power roller to be in rolling contact with the output gear 10 on the outer peripheral edge. The output side disk 4A is formed.
First and Second Steps Since these steps shown in FIGS. 6A and 6B are performed in the same procedure as that of the first embodiment described above, overlapping description is omitted.
Third Step In this third step, partial tempering is performed on the output gear 10 as shown by the oblique grid in FIG. This partial tempering is performed, for example, by a high frequency induction heating method, a flame method, a laser heating method, or the like. The partial tempering of the gear portion of the output gear 10 portion is preferably performed at least over the entire circumference of the teeth. Moreover, the heating temperature at the time of partial tempering is determined according to the conditions described in the third step of Example 1 described above. Also in addition to the above output gear 10 portion, the axial side surfaces 4a, a portion other than 4a, if necessary, can also be subjected to the return portion baked.
Fourth Step Since the fourth step shown in FIG. 6D is also performed in the same procedure as that of the first embodiment, a duplicate description is omitted.

FIG. 7 shows a third embodiment of the present invention corresponding to the sixth aspect. Also in the case of the present embodiment, in the following first to fourth steps, both axial side surfaces 4a and 4a are concave surfaces having an arcuate cross section that causes the peripheral surface of the power roller to be in rolling contact with the output gear 10 on the outer peripheral edge. The output side disk 4A is formed.
First Step Since this first step shown in FIG. 7A is performed in the same procedure as that of the first embodiment described above, a duplicate description is omitted.
Second Step In the second step shown in FIG. 7B, carburizing or carbonitriding is performed, followed by quenching. The surface hardness and the effective hardened layer depth of the axially opposite side surfaces 4a and 4a of the second intermediate material 13 obtained by the second step are set to values suitable for the finished product. The values of the surface hardness and effective hardened layer depth that are suitable for this finished product take into account machining allowances such as finishing performed after the carburizing or carbonitriding process (parts that appear in a state where machining allowances are removed) Hardness, depth in a state excluding machining allowance).
Third Step Since the third step shown in FIG. 7C is performed in the same procedure as the third step of the second embodiment described above, a duplicate description is omitted.
Fourth Step In the fourth step shown in FIG. 7D, only the output gear 10 formed on the outer peripheral edge is subjected to induction hardening and then tempered as shown by the oblique grid. . Further, post-processing such as finishing is performed to obtain an output side disk 4A having a predetermined shape and size.
Note that the present invention is not limited to the half toroidal type as shown in the figure as long as it is a toroidal type continuously variable transmission, and can also be applied to a full toroidal type.

The side view which shows the basic composition of the toroidal type continuously variable transmission used as the object of this invention in the state at the time of maximum deceleration. The side view similarly shown in the state at the time of maximum acceleration. Sectional drawing which shows the 1st example of the toroidal type continuously variable transmission in which the output gear was directly formed in the outer periphery of the output side disk. Sectional drawing which shows the 2nd example. Sectional drawing of the output side disk which shows Example 1 in order of a manufacturing process. Sectional drawing of the output side disk which shows Example 2 in order of a manufacturing process. Sectional drawing of the output side disk which shows Example 3 in order of a manufacturing process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1A input shaft 2 Input side disk 2a Side surface 3 Output shaft 4, 4A Output side disk 4a Side surface 5 Pivot 6 Trunnion 7 Support shaft 8 Power roller 8a Peripheral surface 9 Loading cam device 10 Output gear 11 First intermediate material 12 Hardened layer 13 Second intermediate material

Claims (7)

  Each of the first and second discs, each made of steel, has an axial side surface, which is a concave surface having an arcuate cross section. This structure has a structure in which power is transmitted between the two disks by rolling contact with each other through an oil film, and a power transmission gear is directly formed on the outer peripheral edge of at least one of these disks. In a toroidal-type continuously variable transmission, the disk on which the gear is formed is tempered after carburizing or carbonitriding for surface hardening, and then rolls on the gear portion and the peripheral surface of each power roller. A toroidal-type continuously variable transmission, characterized in that it is manufactured by subjecting the contacting axial direction side portion to induction hardening.   Each of the first and second discs, each made of steel, has an axial side surface, which is a concave surface having an arcuate cross section. This structure has a structure in which power is transmitted between the two disks by rolling contact with each other through an oil film, and a power transmission gear is directly formed on the outer peripheral edge of at least one of these disks. In the toroidal-type continuously variable transmission, the disk on which the gear is formed is allowed to cool after carburizing treatment or carbonitriding treatment for surface hardening, and then rolls around the gear portion and the peripheral surface of each power roller. A toroidal-type continuously variable transmission, characterized in that it is manufactured by subjecting the contacting axial direction side portion to induction hardening.   Each of the first and second discs, each made of steel, has an axial side surface, which is a concave surface having an arcuate cross section. This structure has a structure in which power is transmitted between the two disks by rolling contact with each other through an oil film, and a power transmission gear is directly formed on the outer peripheral edge of at least one of these disks. In the toroidal-type continuously variable transmission, the disk on which the gear is formed is allowed to cool after carburizing or carbonitriding for surface hardening, and after further conditioning, the gear portion and each power A toroidal continuously variable transmission, characterized by being induction-hardened at the axial side surface portion that is in rolling contact with the circumferential surface of the roller. Each of the first and second discs, each made of steel, has an axial side surface, which is a concave surface having an arcuate cross section. This structure has a structure in which power is transmitted between the two disks by rolling contact with each other through an oil film, and a power transmission gear is directly formed on the outer peripheral edge of at least one of these disks. In the toroidal-type continuously variable transmission, the disk on which the gear is formed is axially in rolling contact with the peripheral surface of each power roller including the gear portion after carburizing or carbonitriding for surface hardening. A toroid that is obtained by subjecting a portion that does not require hardness compared to the side surface to partial tempering and then subjecting the side surface in the axial direction and the gear portion to induction hardening. Continuously variable transmission. Each of the first and second discs, each made of steel, has an axial side surface, which is a concave surface having an arcuate cross section. This structure has a structure in which power is transmitted between the two disks by rolling contact with each other through an oil film, and a power transmission gear is directly formed on the outer peripheral edge of at least one of these disks. In the toroidal type continuously variable transmission, the disk on which the gears are formed is cooled after carburizing or carbonitriding for surface hardening, and then the peripheral surfaces of the power rollers including the gears. In addition to performing partial tempering on the parts that do not require hardness compared to the axial side surface that is in rolling contact with the axial side surface, the axial side surface and the gear part are subjected to induction hardening. Toroidal-type continuously variable transmission to be butterflies. Each of the first and second discs, each made of steel, has an axial side surface, which is a concave surface having an arcuate cross section. This structure has a structure in which power is transmitted between the two disks by rolling contact with each other through an oil film, and a power transmission gear is directly formed on the outer peripheral edge of at least one of these disks. In the toroidal-type continuously variable transmission, the disk on which the gear is formed is hardened after carburizing or carbonitriding for surface hardening, and then the peripheral surface of each power roller including the gear portion. A toroid that is obtained by subjecting the gear part to induction hardening after partial tempering is performed on a portion that does not require hardness compared to the axial side surface that is in rolling contact with Type continuously variable transmission.   The toroidal-type continuously variable transmission according to any one of claims 1 to 6, wherein the steel material forming the disk on which the gear is formed is carbon steel containing 0.5 to 1.2% by weight of C.

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