JP6153498B2 - Toroidal continuously variable transmission - Google Patents

Description

  The present invention relates to an improvement in a toroidal continuously variable transmission that is used as a transmission for an automobile or as a transmission for adjusting the operating speed of various industrial machines such as a pump.

  The use of a toroidal type continuously variable transmission as an automobile transmission is partly implemented and well known. 3 to 4 show a basic configuration of a toroidal type continuously variable transmission having a conventional structure. This toroidal-type continuously variable transmission is called a double cavity type, and a pair of input side disks 1a and 1b corresponding to the outer disks described in the claims are each formed by a toroidal curved surface having an arc cross section. The input side inner surfaces 2 and 2 corresponding to the axial side surfaces of the outer disk described in the claims are concentrically synchronized with both ends of the input rotary shaft 3 in a state where the input side inner surfaces 2 and 2 face each other. Supports rotation.

  An output cylinder 5 having an output gear 4 fixed to the outer peripheral surface of the intermediate portion is supported around the intermediate portion of the input rotation shaft 3 so as to be able to rotate relative to the input rotation shaft 3. A pair of output side disks 6a and 6b are supported at both ends of the output cylinder 5 by spline engagement so as to be able to rotate in synchronization with the output cylinder 5. In this state, the output side disks 6a, 6b are respectively formed on the output side inner surfaces 7, 7 of the output side disks 6a, 6b, each of which is a toroidal curved surface having an arc cross section. 2 are opposed to each other.

  In addition, two power rollers 8 and 8 each having a spherical convex surface in the peripheral portion (cavity) between the input side and output side inner side surfaces 2 and 7 around the input rotation shaft 3 are provided. They are arranged one by one. Each of these power rollers 8, 8 is provided on the inner surface of the trunnion 9, 9 via a support shaft 10, 10 whose base half and tip half are eccentric, and a plurality of rolling bearings. 10 is supported so as to be able to rotate around the front half of the 10 and slightly swing displacement about the base half of each of the support shafts 10 and 10. Each trunnion 9, 9 has a tilt shaft 11 provided concentrically for each trunnion 9, 9 at both ends in the length direction (front and back direction in FIG. 3, up and down direction in FIG. 4). , 11 is possible.

  The operation of swinging (tilting) each trunnion 9, 9 is performed by displacing each trunnion 9, 9 in the axial direction of each tilt shaft 11, 11 by hydraulic actuators 12, 12. That is, at the time of shifting, the trunnions 9 and 9 are displaced in the axial direction of the tilt shafts 11 and 11 by supplying and discharging pressure oil to and from the actuators 12 and 12. As a result, the direction of the force acting in the tangential direction of the traction portion, which is a rolling contact portion between the peripheral surface of each of the power rollers 8 and 8 and each of the input side and output side inner surfaces 2 and 7 changes (side Therefore, the trunnions 9 and 9 are oscillated and displaced about the tilting shafts 11 and 11, respectively.

  During operation of the toroidal type continuously variable transmission as described above, one input side disk 1a is rotated by the drive shaft 13 via a loading cam type pressing device 14. As a result, the pair of input-side disks 1a and 1b supported at both ends of the input rotation shaft 3 rotate synchronously while being pressed in a direction approaching each other. This rotation is transmitted to the output side disks 6a and 6b via the power rollers 8 and 8, and is taken out from the output gear 4.

  When the ratio of the rotational speeds of the input rotary shaft 3 and the output gear 4 is changed, and when deceleration is first performed between the input rotary shaft 3 and the output gear 4, the trunnions 9 and 9 are shown in FIG. The power rollers 8 and 8 are swung to the positions shown in FIG. 2 and the peripheral surfaces of the input side inner side surfaces 2 and 2 and the outer peripheral sides of the output side inner side surfaces 7 and 7 respectively. Make contact. On the other hand, in the case of increasing the speed, the trunnions 9 and 9 are swung in the direction opposite to that shown in FIG. 3, and the peripheral surfaces of the power rollers 8 and 8 are moved to the input side inner surfaces 2 and 2. It is made to contact | abut to the outer periphery side part and the center side part of the said output side inner side surfaces 7 and 7, respectively. An intermediate speed ratio (transmission ratio) can be obtained between the input rotary shaft 3 and the output gear 4 by setting the swing angles of the trunnions 9 and 9 to an intermediate position.

  In the case of the conventional toroidal-type continuously variable transmission as described above, the pair of output side disks 6a and 6b and the output gear 4 are separated, and both ends of the output cylinder 5 provided at the center of the output gear 4 are provided. These output side disks 6a and 6b are spline-engaged with each other. For this reason, it is inevitable that the number of parts increases and the axial dimensions of the installed portions of the output side disks 6a and 6b and the output gear 4 increase. On the other hand, for example, Patent Documents 2 and 3 disclose a structure in which a pair of output side disks can be integrated to eliminate the above-described disadvantages. FIG. 5 shows a toroidal type continuously variable transmission of the second example of the conventional structure described in Patent Document 2.

  In the case of the structure shown in the drawing, one output side disk 15 corresponding to the inner disk described in the claims has a shape such that a pair of output side disks are integrated with each other around the intermediate portion of the input rotary shaft 3. And a pair of radial needle bearings 16 and 16 are rotatably supported. An output gear 17 that is a helical gear is provided (fixed) on the outer peripheral surface of the output side disk 15.

In the case of the second example of the conventional structure having the above-described configuration, the number of parts can be reduced as compared with the case of the first example of the conventional structure, and the overall size of the apparatus can be reduced by shortening the axial dimension. I can plan.
However, in the case of the second example of the conventional structure, both the gears 17 are provided at the meshing portion between the output gear 17 provided on the outer peripheral surface of the output side disk 15 and another gear 18 meshing with the output gear 17. , 18, a thrust load Fa (axial load) and a radial load Fr are applied based on the meshing of the helical gears. Further, based on the thrust load Fa, a moment load M is applied to the output side disk 15 in a direction in which the output side disk 15 is inclined.

  Here, the output side disk 15 is supported around the input rotary shaft 3 by a pair of radial needle bearings 16, 16, and the internal gaps of these radial needle bearings 16, 16 and the constituent members. Since displacement in the radial direction is possible by the amount of elastic deformation, there is a possibility of slight tilting with respect to the input rotary shaft 3 based on the load. In this manner, when the output side disk 15 is inclined, the peripheral surfaces of the power rollers 8 and 8, the input side inner surfaces 2 and 2 of the pair of input side disks 1 a and 1 b, and the output side of the output side disk 15. The position (radial position) of the traction portion with the inner side surfaces 19, 19 becomes inconsistent for each of the power rollers 8, 8. Therefore, the magnitude of the power (torque) transmitted by these power rollers 8 and 8 may also be inconsistent for each of the power rollers 8 and 8. As a result, some of the power rollers 8 transmit a larger torque than the other power rollers 8 (the tangential force applied to the traction portion increases). Since the power roller 8 transmitting a large torque is operated with a larger traction coefficient (= tangential force / normal force) than the other power rollers 8, an operation traction coefficient representing an actual operation state is obtained. The difference between the tangential force / normal force according to the torque transmitted by each power roller 8 and the limit traction coefficient that represents the limit value of power transmission without generating gross slip (margin, safety margin) Decreases, and gloss slip is likely to occur.

  The situation where the driving traction coefficient exceeds the limit traction coefficient must be avoided to prevent the occurrence of gross slip in the traction section. For this purpose, for example, the pressing force generated by the loading cam type pressing device 14 is sufficiently large {restricted to the maximum value of the pressing force required when the toroidal continuously variable transmission is operated, It is conceivable that the pressing force (normal force) applied is increased. However, in this case, depending on the driving situation, the surface pressure of each traction section becomes excessive, and the transmission efficiency and durability of the toroidal continuously variable transmission are problematic. Therefore, as a pressing device, for example, as described in Patent Document 4, it is conceivable to use a hydraulic pressing device that can finely adjust the surface pressure (pressing force) of the traction portion. However, if the hydraulic pressure to be introduced is increased excessively in order to keep the traction coefficient of the traction section low, the transmission efficiency and durability are also lowered.

JP 2011-173130 A JP 2008-82360 A JP 11-63139 A JP 2003-130159 A

  In the present invention, in view of the above-described circumstances, even when the inner disk is inclined with respect to the rotation axis based on the load acting on the gear portion provided on the outer peripheral surface, the gross slip is generated in each traction portion. Invented to realize a structure of a toroidal type continuously variable transmission that can effectively prevent the

The toroidal type continuously variable transmission of the present invention is a double cavity type, and includes a rotating shaft, a pair of outer disks, a single inner disk, a plurality of power rollers, a loading device (pressing device), and a loading pressure. Control means.
Among these, the rotating shaft is rotatably supported in the casing, for example.
The pair of outer disks can rotate in synchronization with the rotating shaft at both ends of the rotating shaft in a state where the axial side surfaces of the pair of outer disks are toroidal curved surfaces each having a circular arc cross section. It is supported.
The inner disk has a toroidal curved surface having an arc cross section on both sides in the axial direction, and a gear portion that is a helical gear concentric with the rotating shaft is provided on the outer peripheral surface directly or via another member. Around the middle part of the rotating shaft, it is supported so as to be able to rotate relative to the rotating shaft.
Each of the power rollers has a spherical convex surface, and the pair of outer disks are in contact with the axial side surfaces of the pair of outer disks and the axial side surfaces of the inner disks, respectively. Is supported rotatably on a portion between the axial side surface of the inner disk and the axial side surface of the inner disk.
The loading device is a hydraulic loading device that presses the axial side surface of the pair of outer disks and the axial side surface of the inner disk closer to each other, and shafts of the pair of outer disk and inner disk The surface pressure of the traction part which is a rolling contact part between the direction side surface and the peripheral surface of each power roller is ensured.
The loading pressure control means adjusts the loading pressure corresponding to the magnitude of the pressing force generated by the loading device according to the operating state.

In particular, the toroidal-type continuously variable transmission according to the present invention includes transmission torque calculation means and traction coefficient increase amount calculation means.
Of these, the transmission torque calculating means calculates the magnitude of the transmission torque of the inner disk (torque transmitted from the power roller or torque transmitted to the power roller).
Further, the traction coefficient increase amount calculating means is configured so that, based on the calculated transmission torque, the inner disk is inclined with respect to the rotation shaft {by a load (thrust load) applied to the gear portion along with torque transmission}. The amount of increase in the traction coefficient relative to the traction coefficient of each of the traction sections when the inclination is assumed to be 0 (zero). (The traction coefficient is the highest among the traction coefficients for a plurality of power rollers. Find the increase in things).
The loading pressure control means increases the loading pressure of the loading device based on the calculated value of the traction coefficient increase amount calculating means.

According to the toroidal type continuously variable transmission of the present invention configured as described above, even when the inner disk is inclined with respect to the rotating shaft based on the load acting on the gear portion, gross slip is generated in each traction portion. Things can be effectively prevented.
That is, in the case of the toroidal type continuously variable transmission of the present invention, there is a correlation with the inclination angle (inclination amount) of the inner disk, which has not been considered in the past, and fluctuates based on the load acting on the gear portion. Since the pressing force generated by the hydraulic loading device is controlled in consideration of the transmission torque of the inner disk, it is possible to effectively prevent the occurrence of gross slip in each of the traction sections without excessively increasing this force.
Therefore, it is possible to prevent damage to the axial side surfaces of the inner disk and the pair of outer disks and the peripheral surfaces of the power rollers, and to secure the transmission efficiency of the toroidal continuously variable transmission.

The schematic diagram of the toroidal type continuously variable transmission which shows an example of embodiment of this invention. Similarly block diagram. Sectional drawing which shows the 1st example of a conventional structure. Similarly AA sectional drawing of FIG. Sectional drawing which similarly shows the 2nd example.

[Example of Embodiment]
An example of the embodiment of the present invention will be described with reference to FIGS. The feature of this example is that the input side inner surfaces 2 and 2 of the pair of input disks 1a and 1b and the output side inner surfaces 19 and 19 of the integrated output disk 15 and the power rollers 8 and 8 ( In order to adjust the hydraulic pressure introduced into the hydraulic chamber of the hydraulic pressing device (loading device) 14a in order to properly control the surface pressure of the traction portion which is a rolling contact portion with the peripheral surface of FIGS. As an element representing the operating state to be used, the magnitude of the torque transmitted to the output side disk 15 that has not been considered in the past is adopted. Since the structure of the toroidal continuously variable transmission that appears in the drawing is basically the same as the conventional structure shown in FIG. 5 except that the pressing device is mechanical or hydraulic, Regarding the equivalent part, the overlapping description will be omitted or simplified, and the characteristic part of this example will be mainly described below.

  In the case of this example, the loading pressure setting means 20 and the loading pressure control valve 21 are combined to form the loading pressure control means 22. Of these, the loading pressure setting means 20 includes, as elements (operating parameters) representing the operating state of the toroidal continuously variable transmission, the gear ratio, the input rotational speed, the input torque, the temperature (oil temperature) of the traction oil, A signal representing a set traction coefficient, which is preset based on the performance of the traction oil such as the type of traction oil and the oil temperature, is input. The loading pressure setting means 20 is introduced into the hydraulic chamber of the pressing device 14a according to the loading pressure corresponding to the operating state, that is, the force to be generated by the pressing device 14a, based on the signals representing these elements. The power pressure is set (calculated), and a signal (target signal) representing the oil pressure is output. The loading pressure control valve 21 introduces a predetermined hydraulic pressure (represented by the target signal) into the hydraulic chamber of the pressing device 14a based on the target signal. Then, the pressing device 14a generates a pressing force corresponding to each of the operation parameters, and ensures a surface pressure of each of the traction portions.

The above points are the same as those of a conventionally known toroidal type continuously variable transmission including a hydraulic pressing device 14a. Note that the hydraulic pressure set by the loading pressure setting means 20 based on the operation parameters is that the output disk 15 is not inclined with respect to the input rotating shaft 3 (the rotation of the disks 1a, 1b, 15). This is a standard value that is optimal in a state where the central axes coincide with each other. A load (mainly a force acting on a meshing portion between the output gear 17 that is a helical gear and another gear 18 (see FIG. 5) that meshes with the output gear 17 formed on the outer peripheral surface of the output side disk 15. Based on the moment load M), the optimum value of the hydraulic pressure in a state where the output side disk 15 is inclined with respect to the input rotating shaft 3 is higher than the standard value for the reason described above.
The characteristic part of the present example described below is added to the standard value based on the magnitude of torque transmitted to the output side disk 15 having a correlation with the inclination angle (tilt amount) of the output side disk 15. The power addition value is obtained, and the sum of the standard value and the addition value is introduced into the hydraulic chamber of the pressing device 14a.

  In order to obtain the added value, the toroidal-type continuously variable transmission of this example includes a transmission torque calculation means 23 and a traction coefficient increase amount calculation means 24. Based on the calculated value of the transmission torque calculating means 23, the traction coefficient increase amount calculating means 24 calculates a signal representing the driving traction coefficient increase amount based on the inclination of the output side disk 15. Further, a signal representing the increase amount of the driving traction coefficient is input to the loading pressure setting means 20.

The transmission torque calculation means 23 obtains the magnitude of torque (torque transmitted between the input side disks 1a, 1b and the output side disk 15) transmitted to the output side disk 15, for example, The transmission torque is calculated using the relational expression (calculation formula).
Transmission torque = Transmission input torque x Toroidal continuously variable transmission gear ratio (reduction ratio)

The traction coefficient increase amount calculation means 24 determines that the output side disk 15 is inclined with respect to the input rotating shaft 3 based on the torque transmitted to the output side disk 15 obtained by the transmission torque calculation means 23. Increased amount of driving traction coefficient (tangential force / normal force according to torque transmitted by each power roller 8) of each traction section (out of driving traction coefficients related to the plurality of power rollers 8, 8) , The amount of increase with respect to the one having the highest traction coefficient with respect to the driving traction coefficient when the inclination is set to 0) is obtained by a previously installed calculation formula or map.
This calculation formula or map is obtained by experiment or computer simulation. When it is obtained by experiment, for example, it is performed as follows.

  In other words, an experimental model that transmits torque via a plurality of power rollers (a number corresponding to the actual machine) between a pair of input disks and an integrated output disk is created, and a toroidal-type continuously variable transmission In a state where the speed ratio of the machine is constant and the inclination angle of the output side disk is constant, the pressing force generated by the pressing device is gradually changed to generate a gross slip. Specifically, from a state in which a sufficiently large pressing force is applied to prevent the occurrence of gross slip, this pressing force is gradually reduced, and the pressing force (normal force) at the moment the gross slip occurs and the moment The limit traction coefficient is obtained from the ratio with the transmission torque (tangential force). By conducting such an experiment a plurality of times while changing the tilt angle of the output side disk, the relationship between the tilt angle of the output side disk and the increase amount of the driving traction coefficient is obtained. On the other hand, the relationship (relational expression) between the tilt angle of the output side disk and the transmission torque of the output side disk is the inside of a bearing (for example, a radial needle bearing) for rotatably supporting the output side disk with respect to the rotating shaft. It is obtained in advance by using design-required values such as the gap and the amount of elastic deformation of each constituent member. Therefore, the relationship between the transmission torque and the increase amount of the driving traction coefficient can be obtained from these. This relationship is obtained for each of the different gear ratios, and a calculation formula (empirical formula) or map representing the relationship between the transmission torque and the increase amount of the driving traction coefficient is obtained for each gear ratio. Then, software including the obtained empirical formula or map is installed in the traction coefficient increase amount calculation means 24 in advance.

  Further, the loading pressure control means 22 increases the loading pressure of the pressing device 14 a based on the calculated value of the traction coefficient increase amount calculating means 24. In other words, an added value corresponding to the increase amount of the driving traction coefficient is added to the standard value.

According to the toroidal type continuously variable transmission of the present example configured as described above, the input rotation is based on the load acting on the output gear 17 which is a helical gear formed on the outer peripheral surface of the output side disk 15. Even when inclined with respect to the shaft 3, the pressing device 14a does not excessively increase the force with which the discs 1a, 1b, and 15 are pressed, so that it is difficult for gloss slip to occur in the traction portions.
That is, in the case of the toroidal-type continuously variable transmission of this example, transmission torque having a correlation with the inclination angle of the output-side disk 15 that has fluctuated based on the load acting on the output gear 17 has not been considered in the past. In consideration of the above, the force for pressing each of the disks 1a, 1b, 15 is controlled. Therefore, even when the output side disk 15 is tilted, it is possible to prevent the occurrence of gloss slip at each of the traction portions without excessively applying the pressing force. In other words, even if the difference between the limit traction coefficient of each traction section and the preset traction coefficient set in advance is not excessively increased, the loading pressure calculated based on the set traction coefficient is determined according to the transmission torque. Since the correction is made, the limit traction coefficient can always exceed the driving traction coefficient. The fact that the limit traction coefficient exceeds the driving traction coefficient contributes to the prevention of gross slip. This will lead to ensuring the transmission efficiency of
For this reason, the input side inner surfaces 2 and 2 of the pair of input side disks 1a and 1b, the output side inner surfaces 19 and 19 of the output side disk 15, and the peripheral surfaces of the power rollers 8 and 8 are damaged. And the transmission efficiency of the toroidal continuously variable transmission can be ensured.

  The present invention is not limited to a structure in which torque is transmitted from the pair of outer disks to the inner disk via the power roller as in the example of the embodiment described above, but a pair of the inner disk via the power roller. It can also be applied to a structure that transmits torque to the outer disk. In this case, the inner disk becomes the input side disk, and the pair of outer disks become the output side disks. Further, the present invention can be implemented in combination with a planetary gear type transmission as well as a toroidal type continuously variable transmission alone.

DESCRIPTION OF SYMBOLS 1a, 1b Input side disk 2 Input side inner surface 3 Input rotation shaft 4 Output gear 5 Output cylinder 6a, 6b Output side disk 7 Output side inner surface 8 Power roller 9 Trunnion 10 Support shaft 11 Tilt shaft 12 Actuator 13 Drive shaft 14 , 14a Pressing device 15 Output side disk 16 Radial needle bearing 17, 17 Output gear 18 Another gear 19 Output side inner surface 20 Loading pressure setting means 21 Loading pressure control valve 22 Loading pressure control means 23 Transmission torque calculation means 24 Traction coefficient increase Quantity calculation means

Claims (1)

A rotation shaft, a pair of outer disks, a single inner disk, a plurality of power rollers, a loading device, and a loading pressure control means;
The pair of outer disks can rotate in synchronization with the rotating shaft at both ends of the rotating shaft in a state where the axial side surfaces of the pair of outer disks are toroidal curved surfaces each having a circular arc cross section. Supported,
The inner disk has a toroidal curved surface with an arc cross section on both sides in the axial direction, and a gear portion that is a helical gear concentric with the rotating shaft on the outer peripheral surface, and around the intermediate portion of the rotating shaft, It is supported so that it can rotate relative to this rotation axis.
Each of the power rollers has a spherical convex surface in a rolling contact state with the axial side surface of the pair of outer disks and the axial side surface of the inner disk. It is rotatably supported at the part between the axial side and the axial side of the inner disk,
The loading device is a hydraulic loading device that presses the axial side surface of the pair of outer discs and the axial side surface of the inner disc toward each other so that the pair of outer and inner discs Securing the surface pressure of the traction portion which is a rolling contact portion between the axial side surface and the peripheral surface of each power roller;
In the toroidal continuously variable transmission, the loading pressure control means adjusts the loading pressure corresponding to the magnitude of the pressing force generated by the loading device according to the operating state.
A transmission torque calculating means for calculating a transmission torque of the inner disk;
A traction coefficient increase amount calculating means for obtaining an increase amount of the traction coefficient of each traction section, which is caused by the inner disk being inclined with respect to the rotation axis based on the calculated transmission torque; Prepared,
The toroidal-type continuously variable transmission characterized in that the loading pressure control means increases the loading pressure of the loading device based on the calculated value of the traction coefficient increase amount calculating means.

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