JPH11303962A - Toroidal-type continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the torque transmitting capacity and durability of a toroidal- type continuously variable transmission by restraining the spin of a cam roller. SOLUTION: The toroidal-type continuously variable transmission is provided with a power roller 8 to be pinched between coaxially arranged input and output discs 5, 6, a cam flange 2 arranged coaxially with the input disc 5 and connected to an input shaft 1, and a cam roller 3 to be pinched between the cam flange 2 and the back surface of the input disc 5 and having a conical rolling surface. The vertex A on an extension line of a conical rolling surface is arranged on the side opposite to the cam roller 3 across the rotational axis C of the cam flange 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a thrust force generating mechanism of a toroidal type continuously variable transmission used for a vehicle or the like.

[0002]

2. Description of the Related Art In a toroidal type continuously variable transmission, power is transmitted by sandwiching and pressing a power roller between input and output disks. As a structure for generating a thrust force for sandwiching the power roller, ASME PAPER 7
The one disclosed in 5-WA / Aut-16 is known.

[0003] This is a double cavity type in which two sets of input / output disks 95 and 96 are coaxially arranged on an output shaft 99, as shown in FIGS. Power rollers 98, 98 sandwiched between
To generate a thrust force so as to be pinched and pressed according to the input torque from the input shaft 91.

The output shaft 99 is meshed with a gear 91A provided on the input shaft 91, and is connected to a cam flange 92 having cam surfaces 92A at both end surfaces.
Input disks 95, 95 which are rotatable relative to the output shaft 99 and are displaceable in the axial direction are provided on both sides of 2.

A cam surface is formed on the rear surface of the input disk 95 in the same manner as a cam flange, and cam rollers 93, 93 formed of tapered rollers having a conical rolling surface are interposed between the cam surfaces. Be mounted.

When torque is transmitted from the input shaft 91 to the cam flange 92, the cam flange 92 first starts rotating, and as shown in FIG. 9, the rear surface of the input disk 95 and the cam surface 92A of the cam flange 92. The cam roller 93 interposed therebetween presses the input disk 95 in the axial direction in order to climb the inclination of the cam surface 92A, and starts the power roller 98,
A pressing thrust force is generated according to the input torque.

The cam roller 9 which generates the thrust force
As shown in FIG. 8, reference numerals 3 and 93 denote the vertices A of the cone where the extension line of the rolling surface and the rotation axis intersect (hereinafter referred to as the conical vertex A).
To the rotation axis Cx of the cam flange 92 (= the rotation axis of the output shaft 99) to reduce the spin loss of the cam roller 93.

[0008]

However, in the above-mentioned conventional toroidal-type continuously variable transmission, the cam surface 92A is inclined with respect to the rotation direction of the cam flange 92. The spin of the cam roller 93 does not become completely zero even if the rotation axes Cx of the 92 are matched.

That is, in FIG.
The rolling lengths l ₁ and l ₂ at the turning radii R ₁ and R ₂ , which are both ends of the effective length of the cam surface 92A, are equal to the lead (360 °) of the cam surface 92A.
Let L be the displacement when rotated)

[0010]

(Equation 1)

Is represented by

Accordingly, the radius r ₁ and r ₂ of the cam roller 93 corresponding to the radius R ₁ and R _2, the cam flange 9
The rolling speed ratio S of 2 is

[0013]

(Equation 2)

Here, R ₁ / R ₂ = r ₁ / r ₂ .

Therefore, the slip ratio of the radii r ₁ and r ₂ of the cam roller 93, that is, the spin amount s, is obtained by substituting R ₁ / R ₂ = r ₁ / r ₂ into the above equation (3).

[0016]

(Equation 3)

## EQU1 ##

Here, assuming that R ₁ is the minimum diameter position of the cam roller 93 and R ₂ is also the maximum diameter position, then R ₁ ≠ R ₂ (4), so that the speed ratio S is S ≠ 1. ... (5)

Therefore, the spin amount s is

[0020]

(Equation 4)

As a result, spin occurs in the cam roller 93, and a speed difference is generated in the contact surface between the cam roller 93 and the cam surface 92A, and this speed difference becomes a frictional force.

Here, the effect of this frictional force on the thrust force generated by the cam roller 93 will be considered.

First, when the input torque is increased, as shown in FIG.
When the rotational force Ft is applied to the cam surface 92A with which the cam roller 93 is in contact, the normal force Fc of the slope and the frictional force f act on the cam surface 92A.
Since the normal force Fc and the frictional force f balance the rotational force Ft, if the inclination angle of the cam surface 92A is θ, the following relationship is established: Ft = Fc × sin θ + f × cos θ (7) Fc = (Ft−f × cos θ) / sin θ (8)

Assuming that the thrust force applied by the cam roller 93 to the input disk 95 is Fa, the thrust force Fa
Is the component of the normal force Fc in the axial direction of the cam flange 92, so that Fa = Fc × cos θ = (Ft−f × cos θ) / tan θ (9)

Therefore, when the input torque increases, the actually generated thrust force Fa becomes smaller than the set value of the thrust force Fa (= Ft / tan θ) as shown in FIG.
f × cos θ / tan θ, the power roller 98 cannot obtain a sufficient thrust force for transmitting the torque, causing the power roller 98 to slip and reducing the torque transmission capacity of the continuously variable transmission. There was a problem of doing.

On the other hand, when the input torque is reduced, as shown in FIG. 10, the direction of the frictional force f is opposite to the direction when the torque is increased.
Is given by: Fa = (Ft + f × cos θ) / tan θ (10)

Therefore, when the input torque is reduced, the thrust force Fa actually generated becomes f × cos θ / tan θ with respect to the set value of the thrust force Fa, as shown in FIG.
Therefore, there is a problem that the thrust force Fa for pressing the power roller 98 becomes excessive, and the durability of the power roller 98 and the input / output disks 95 and 96 is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to suppress the spin of a cam roller and secure the torque transmission capacity and durability of a toroidal type continuously variable transmission.

[0029]

According to a first aspect of the present invention, there is provided a power roller sandwiched between input / output disks arranged coaxially, and a cam arranged coaxially with the input disk and connected to an input shaft. A toroidal-type continuously variable transmission having a cam roller provided with a conical rolling surface, sandwiched between the cam and the rear surface of the input disk, wherein the cam roller is on an extension of the conical rolling surface. Are disposed on the opposite side of the cam roller with respect to the rotation axis of the cam.

In a second aspect based on the first aspect, the vertex of the cam roller is separated from the rotating shaft by a predetermined amount so that the spin of the cam roller is minimized.

According to a third aspect of the present invention, in the second aspect, the apex of the cam roller is further rotated in accordance with the radial displacement of the cam roller than a predetermined amount at which the spin of the cam roller is minimized. Move away from the axis.

[0032]

Accordingly, the first aspect of the present invention is to dispose the apex, which intersects on the extension of the conical rolling surface of the cam roller, on the opposite side of the cam roller with the rotation axis of the cam interposed therebetween. As compared to the case where the apex of the cam roller coincides with the rotation axis, the spin can be reduced, the frictional force due to the spin is reduced, and the actually generated thrust force substantially matches the set value. It is possible to suppress the deviation of the thrust force due to the fluctuation of the input torque as in the conventional example, to prevent the durability of the power roller and the input / output disk from being reduced due to the excessive thrust force, and to reduce the excessive thrust force. By preventing the power roller from slipping and preventing the power roller from slipping, the torque transmission capacity of the toroidal-type continuously variable transmission can be secured.

According to a second aspect of the present invention, a vertex that intersects on an extension of the conical rolling surface of the cam roller is disposed on the opposite side of the cam roller with respect to the rotation axis of the cam, and is separated from the rotation axis by a predetermined amount. The amount of spin =
0, the cam roller can roll without slipping in the contact surface between the cam and the rear surface of the input disk, and the frictional force due to spin occurs as in the conventional example. And the thrust force actually generated can be substantially matched with the set value, and the deviation of the thrust force due to the fluctuation of the input torque as in the conventional example can be almost eliminated, and the excessive thrust force can be obtained. This prevents the durability of the power roller and the input / output disk from deteriorating due to the force and prevents the power roller from slipping due to an excessive reduction in the thrust force, thereby ensuring the torque transmission capacity of the toroidal type continuously variable transmission.

According to the third aspect of the present invention, the cam roller is slightly displaced to the outer periphery in the radial direction by centrifugal force due to rotation or load from the cam. By setting the distance from the axis to the apex, when the cam roller 3 is displaced to the outer peripheral side due to centrifugal force or load, the position of the apex is set to a predetermined amount where the spin amount = 0 and the input torque fluctuates. Regardless, a predetermined thrust force can be generated, and the durability and torque transmission capacity of the toroidal-type continuously variable transmission can be reliably ensured.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 to 4 show a case where the present invention is applied to a toroidal type continuously variable transmission of a single cavity type.
As shown in FIG. 1, an input disk 5 and an output disk 6 provided with a toroidal groove on an opposing surface are disposed coaxially with an input shaft 1 supported by a casing 10 via a bearing 12 and the like. 1, a cam flange 2, a cam roller 3, an input disk 5, an output disk 6, and an output gear 9 are sequentially arranged from the right side, and a power roller 8 supported by a trunnion 7 is interposed between the input and output disks 5, 6. Be mounted.

As will be described later, the power roller 8 is driven by the input / output disks 5, 6 by the thrust force generated by the cam flange 2 and the cam roller 3 according to the input torque.
To transmit the torque.

The output gear 9 connected to the back surface of the output disk 6 is supported by a casing 10 via a bearing 13, and the output disk 6 and the output gear 9 are rotatable relative to the input shaft 1. Becomes

A bearing 12 that supports the input shaft 1 is provided adjacent to the bearing 13 to support a thrust force from the cam flange 2 and the cam roller 3. In FIG. 1, the input shaft 1 and the bearing 12 on the left side of the bearing 12
A disc spring 11 is interposed between the side and the side, and when no load is applied, the disc spring 11 urges the cam flange 2 to the left in the figure,
A preload is applied to the power roller 8 via the cam roller 3.

Here, the cam flange 2 is integrally connected to the input shaft 1 while the input disk 5 is supported so as to be rotatable relative to the input shaft 1 and displaceable in the axial direction. A concave cam surface 20 having a predetermined inclination is provided on the opposing surfaces of the cam flange 2 and the input disk 5,
A cam roller 3 housed in the holder 4 is interposed between the cam surfaces 20 and 50.

Here, as shown in FIGS. 2 and 3, the cam roller 3 is constituted by a tapered roller having a conical rolling surface, and the small-diameter end 3a is directed toward the axis C of the input shaft 1. Are accommodated in the frame 40 of the retainer 4 at 90-degree intervals with the large-diameter end 3b facing the outer periphery. Note that the rotation axis Y of the cam roller 3 coincides with the radial direction of the retainer 4 and the cam flange 2.

The cam flange 2 and the cam surfaces 20 and 50 of the input disk 5 which face each other approach the input shaft 1 along the conical cam roller 3 as shown in the sectional views of FIGS. As shown in FIG. 2, the recesses are formed as recesses which are inclined in the circumferential direction in accordance with the arrangement intervals of the plurality of cam rollers 3, and the cam flange 2 and the input disk 5 are formed in FIG. When rotated relatively, the cam roller 3 rolls on the inclined surface of the cam surface 20 fixed to the input shaft 1 side, so that the input disk 5 is displaced in the direction of the axis C of the input shaft 1 toward the output disk 6. Thus, a thrust force Fa for holding and pressing the power roller 8 is generated.

As shown in FIG. 1 or FIG. 4, the cam roller 3 which generates the thrust force Fa has a vertex A (hereinafter referred to as a cone) where an extension line of the rolling surface of the cam roller 3 and the rotation axis Y of the cam roller 3 intersect. , A cone vertex A) is disposed on the opposite side of the cam roller 3 with respect to the axis C of the input shaft 1 (= the rotation axis of the cam flange 2) and set at a position separated from the axis C by a predetermined amount a. .

The operation as described above will now be described.

Since the conical vertex A is arranged on the opposite side of the cam roller 3 with respect to the axis C, and the position of the conical vertex A is set to be a predetermined amount a in the radial direction from the axis C,
The spin amount s (slip ratio) of the cam roller 3 is as follows.

First, in the same manner as in FIG. 8 of the conventional example, as shown in FIG. 4, the turning radii around the input shaft 1 at both ends of the effective length of the cam roller 3 are defined as R ₁ and R _2. Assuming that the rotation radius at the minimum diameter position R ₁ is r ₁ , the rotation radius at the maximum diameter position R ₂ of the cam roller 3 is r ₂ , and the lead of the cam surface 20 is L, the equation (6) shown in the conventional example is used. ,

[0047]

(Equation 5)

Is as follows.

Here, assuming that the spin amount s = 0,

[0050]

(Equation 6)

Thus, there is a solution in which the spin amount s becomes zero.

Here, considering the polarity of the predetermined amount a, since the turning radius R ₁ <R ₂ ,

[0053]

(Equation 7)

In other words, the above equation (12) is

[0055]

(Equation 8)

Is as follows. Here, when the above equation (12) is divided into a denominator and a numerator, from R1 <R2, B-1> 0 (15)

[0057]

(Equation 9)

Therefore, a> 0.

That is, the predetermined amount a from the axis C to the conical vertex A is always a positive value, and the spin amount s = 0, and the conical vertex A of the cam roller 3 is connected to the rotational axis of the cam flange 2. C, the spin amount s of the cam roller 3 becomes 0, and the cam roller 3 has a small-diameter end 3 a and a large-diameter end 3 within the contact surface with the cam surfaces 20 and 50.
The rolling can be performed without generating the speed difference b, and the frictional force due to the spin does not occur as in the conventional example, and the thrust force Fa actually generated is set as shown in FIG. Values can be substantially matched with each other, so that the deviation of the thrust force Fa due to the fluctuation of the input torque as in the prior art can be almost eliminated, and the power roller 8 and the input / output disk due to the excessive thrust force Fa can be eliminated. 5,
6, the power roller 8 is prevented from slipping by preventing the thrust force Fa from excessively lowering, and the torque transmission capacity of the toroidal-type continuously variable transmission can be secured.

FIG. 6 shows a second embodiment, in which the position of the conical vertex A in the first embodiment is more than the position of the predetermined amount a from the rotation axis C of the cam disk 2 where the spin amount s = 0.
The opposite side is obtained by adding a predetermined amount b, and the other configuration is the same as that of the first embodiment.

A force Fb is applied to the cam roller 3 toward the outer periphery in the radial direction by the load Fc from the inclined cam surface 20 and the centrifugal force Fr.

The force Fb is expressed as follows: Fb = 2Fd + Fr (17) where Fd is the radial component of the load Fc.

Then, the cam roller 3 is slightly displaced to the outer peripheral side by the force Fb directed to the outer periphery so as to push the holder 4 apart.

Therefore, the centrifugal force Fr and the radial component force Fd
, The displacement b of the cam roller 3 is determined in advance by an experiment or the like, and the position of the conical vertex A from the axis C to the conical vertex A ′ is set to the opposite side of the axis C by the displacement b. By setting the distance to a + b, when the cam roller 3 moves to the outer peripheral side due to the centrifugal force Fr and the load Fc, the position of the conical vertex A is set to the position of the predetermined amount a where the spin amount s = 0, The predetermined thrust force Fa can be generated irrespective of the change in the input torque, and the durability and torque transmission capacity of the toroidal-type continuously variable transmission can be reliably ensured.

[Brief description of the drawings]

FIG. 1 is a half sectional view of a toroidal type continuously variable transmission showing one embodiment of the present invention.

FIG. 2 is a side view of a cam flange and an input disk.

FIG. 3 is a front view of the retainer.

FIG. 4 is a sectional view of a main part of a cam flange and a cam roller.

FIG. 5 is a graph showing an operation, showing a relationship between an input torque and a thrust force.

FIG. 6 is a sectional view of a main part of a cam flange and a cam roller according to the second embodiment.

FIG. 7 is a sectional view of a toroidal type continuously variable transmission, showing a conventional example.

FIG. 8 is a sectional view of a main part of a cam flange and a cam roller.

FIG. 9 is a conceptual diagram showing the movement of a cam flange and a cam roller, when the torque is increased.

FIG. 10 is a conceptual diagram showing the movement of a cam flange and a cam roller, when torque is reduced.

FIG. 11 is a graph showing the operation of the conventional example, showing the relationship between input torque and thrust force.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input shaft 2 Cam flange 3 Cam roller 4 Cage 5 Input disk 6 Output disk 8 Power roller 20, 50 Cam surface

Claims (3)

[Claims] A power roller sandwiched between input / output disks coaxially arranged; a cam coaxially arranged with the input disk and connected to an input shaft; and a cam and a back surface of the input disk. In a toroidal-type continuously variable transmission including a cam roller having a conical rolling surface sandwiched between the cam rollers, the cam roller has a vertex on an extension of the conical rolling surface,
A toroidal-type continuously variable transmission, which is disposed on a side opposite to a cam roller with respect to a rotation axis of the cam. 2. The toroidal-type continuously variable transmission according to claim 1, wherein an apex of the cam roller is separated from the rotating shaft by a predetermined amount so that a spin of the cam roller is minimized. 3. The cam roller according to claim 2, wherein the apex of the cam roller further moves away from the rotation axis in accordance with a radial displacement of the cam roller than a predetermined amount at which the spin of the cam roller is minimized. The toroidal-type continuously variable transmission as described in the above.