JPH0132380B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a continuously variable transmission using spheres. A conventional device of this type is shown in FIG. Figure 1 is a partial cross-sectional view showing a conventional device. In the figure, 1 is a steel ball (generally a sphere), 2
3 is the spindle shaft inserted into the center hole of steel ball 1;
4 is a needle bearing between the steel ball 1 and the spindle shaft 2, 4 is an iris plate, 4a is a cam groove provided in the iris plate 4 and through which the spindle shaft 2 passes, 4b is a worm wheel provided on the outer periphery of the iris plate 4, 5 is worm wheel 4b
worm gear provided in , 6 is a housing,
7 and 8 are brackets, respectively, and 6, 7, and 8 are collectively referred to as the housing structure, 7a and 8a are grooves provided in the brackets 7 and 8, respectively, and 9 is an input shaft (generally the first rotating shaft). 10 is an output shaft (generally a second rotating shaft). Axis 9, 10
The axes of the steel ball 1 coincide with each other, and when considering rectangular coordinates with this axis as the x-axis, the cross section shown in Fig. 1 is a cross section on a plane that includes the A plurality of balls are provided so that the center of each ball is located at a point at a distance r from the x-axis, that is, on the circumference of a radius r, and two adjacent steel balls 1 are arranged so that the distance between their centers is uniform. The direction of the grooves 7a and 8a is such that the projection on a plane perpendicular to the x-axis extends in the radial direction with the x-axis as the center, and the cam groove 4a has a direction in which the iris plate 4
The spindle shaft 2 is shaped so that when it rotates around the shaft, both ends of the spindle shaft 2 fit into grooves 7a and 8a and move. 11 is an outer ring, 12 is an input side drive cone, 13 is an output side drive cone, 14 is an input side pressure roller, 1
5 is the output side pressure roller, 16 is the bearing, 17
is lubricating oil, and 18 and 19 are oil seals, respectively. The outer ring 11 is in pressure contact with the outside of the steel ball 1, and the drive cones 12 and 13 are in pressure contact with the steel ball 1 to transmit rotation by friction, and the pressure rollers 14 and 1
5 exerts a force to press the drive cones 12 and 13 against the steel ball 1, and a bearing 16 is provided to support the output shaft 10 with the bracket 8, and a lubricating oil 17 is provided.
is contained in an oil reservoir formed within the housing structure. Next, the operation will be explained. When the worm gear 5 is rotated by a handle (not shown), the iris plate 4 rotates around the x-axis via the worm wheel 4b. At this time, the positional relationship between the grooves 7a, 8a and the cam groove 4a changes, and the spindle shaft 2
It will be tilted from a direction parallel to the axis. Fig. 2 is an explanatory diagram explaining the operation of the device shown in Fig. 1, where the same symbols as in Fig. 1 indicate the same parts, N ₁ is the input rotation speed, N ₂ is the output rotation speed, and R ₁ and R ₂ are Contact radius of drive cones 12 and 13, r ₁ ,
r ₂ are drive cones 12 and 13 of steel ball 1, respectively
If the radius of contact and θ is the inclination of the spindle shaft 2, then N ₂ = R ₁ / r ₁・r ₂ / R ₂・N ₁ and when R ₁ = R ₂ , N ₂ = r ₂ / r ₁ N ₁ Therefore, when r ₁ > r ₂ , the speed is decelerated, and when θ is in the opposite direction to the example shown in FIG. 2, r ₁ <r ₂ , and the speed is increased. In this case, each drive cone 12, 13 is rotated integrally with the shaft 9, 10 by pressure rollers 14, 15, respectively, and at the same time, the drive cone 12, 13 is rotated toward the center by an axial component force corresponding to the transmitted torque. As a result, a pressing force necessary for frictional transmission is generated between each drive cone 12, 13 and the steel ball 1. Further, the steel ball 1 receives an inward pressing force from the outer ring 11, so that the balance between the respective pressing forces is maintained. By the way, the pushing force required for friction transmission increases as the torque to be transmitted increases, so it is sufficient to apply a large pushing force only on the low-speed rotation side where the torque is large, but with the structure shown in Figure 1, the pushing force increases. In order to balance the pressure, a similarly large pressing force acts on the high-speed rotation side. Since applying an excessive pressing force on the high-speed rotation side will generate a large friction loss, the upper limit of the allowable pressing force is limited, and this becomes the upper limit of the pressing force on the low-speed rotation side. However, if the pressing force on the low-speed rotation side is low, slippage will occur when the rotational torque is large, and this slippage must be limited to a predetermined percentage or less. Therefore, the upper limit of the pressing force on the high-speed rotation side is This limits the side torque, which in turn limits the transmission horsepower capacity. Furthermore, as is clear from Figure 1, the structure in which a spindle shaft is provided on a sphere and the inclination angle of the spindle shaft is controlled requires a large number of parts and requires high-precision machining, which not only increases manufacturing costs but also increases the manufacturing cost as described above. The disadvantages were that the transmitted horsepower was limited and the durability was low. This invention was made to eliminate the above-mentioned drawbacks of the conventional apparatus, and embodiments of the invention will be described below with reference to the drawings. FIG. 3 is a partial sectional view showing an embodiment of the present invention, in which 6, 7, 8, 9, 10, 17, 18, and 19 indicate parts corresponding to the same reference numerals in FIG. 1, and 9a is an input A spline portion 21 provided on the shaft 9 is a steel ball (generally a sphere). The axial direction of the first and second rotating shafts 9 and 10 is the x-axis, and a plurality of steel balls 2
1 are arranged on a plane perpendicular to the x-axis, on the circumference at a distance r from the x-axis, with uniform distances between the centers, as in the case of FIG. Similarly to FIG. 1, the cross section in the figure shows a cross section along a plane including the x-axis. 22 is an outer ring fixed to the housing structure and having a conical surface 22a in pressure contact with the steel ball 21;
28 is an input side drive cone whose outer circumferential surface is concavely curved and makes point contact with the outer circumference of the steel ball 21;
29 is a fixed plate for positioning the input side drive cone 28; 30 is a thrust bearing between the fixed plate 29 and the input side drive cone 28; 31
are a plurality of pins provided on the fixing plate 29 and passing through the bracket 7; 32 is a gear nut; by rotating it left and right, the input side drive cone is connected via the pin 31, the fixing plate 29, and the thrust bearing 30; 28 in the x-axis direction.
33 and 34 are bearings provided on the bracket 7 that supports the input shaft 9; 35 is an output side drive plate having a semicircular groove 35a and making point contact with the outer periphery of the steel ball 21; this output side drive plate 35 is connected to the output shaft 10; Fixed. FIG. 4 is an explanatory diagram illustrating an example of the operation of the device shown in FIG. 3. For each steel ball 21, the origin is the center of the steel ball, and the and expressed in rectangular coordinates, with the Y axis being the direction perpendicular to the plane containing the x-axis and the X-axis (the plane of the paper in Figure 4), and the Z-axis being the direction perpendicular to the plane containing the X-axis and Y-axis. do. Also, point A is the contact point between the input side drive cone 28 and the steel ball 21, point B is the contact point between the output side drive plate 35 and the steel ball 21, and point C is the contact point between the outer ring 22 and the steel ball 21. , each contact point A,
The pressing force at B and C is F _A , as shown in the figure, respectively.
Let F _B and F _C be. Next, coordinate transformation

Considering [Formula], rotate the X-Z plane by an angle β around the Y axis, that is, set the angle XOM = β, and then rotate the YOM plane around the ζ axis by an angle θ, so that point B is on the ξ axis. shall come to In this case, the coordinate transformation formula is as follows. By the way, regarding the coordinate axes shown in FIG. 4, as long as the position of the positioning fixing plate 29 on the x-axis is fixed, the positions of points A, B, and C are fixed, and the points A, B, and C are supported by these three points. Center point 0 of steel ball 21
It can be seen that it is fixed. Therefore, it is best if the pressing forces F _A , F _B , and F _C are vectorally balanced, and the pressing force on the low-speed rotation side and the pressing force on the high-speed rotation side must be equal, as in the case of Fig. 1. There is no restriction that there is no equilibrium. Therefore,
In the device shown in FIG. 3, the pressing force on both the low-speed rotation side and the high-speed rotation side is sufficient to correspond to the load torque, and the minimum pressing force required for frictional transmission is sufficient.
If F _A and F _B are arbitrarily determined, F _C that is in equilibrium with them will be generated. The spherical shape of the semilunar groove 35a is shown in FIGS. 5 to 7. FIG. 5 is a front view of the drive plate 35, FIG. 6 is a cross-sectional view taken by - in FIG.
FIG. 7 is a developed cross-sectional view on the circumference of FIG. 5. In these figures, the same reference numerals as in FIGS. 3 and 4 indicate the same parts, and 35b is indicated by a two-dot chain line.
indicates the contour lines of the semilunar groove 35a. Regarding the coordinate axes shown in Fig. 4, the steel ball 1
Since rotation around the ξ-axis is free, it rotates around the ξ-axis. On the other hand, when viewed from the coordinate axis with one point on the x-axis as the origin, the input side drive cone 28 is rotating around the x-axis, so point A also rotates, and the steel ball 21 moves ξ according to this rotation. In addition to rotation around the axis, the planetary motion is accompanied by revolution, and this motion is transmitted from point B to the output side drive plate 35. The input rotation speed is N _IN , the output rotation speed is N _OUT , the distance from the x-axis to point A is R ₁ , the distance from the x-axis to point C is R ₃ , the distance from the ξ-axis to point A is r ₁ , If the distance from the ξ axis to point C is r ₃ , then N _IN = (1 + r ₁ /R ₁ · R ₃ /r ₃ )N _OUT (2). When changing the gear ratio, by rotating the gear nut 32 to the right or left and changing the axial position of the input drive cone 28, the positions of points A, B, and C on the X-Y-Z coordinates in Figure 4 can be changed. By changing the equation (2),
Change the values of R ₁ , R ₃ , r ₁ , and r ₃ . A change in the position of point B with respect to the X-Y-Z coordinates results in a change in the ξ axis, which in turn results in a change in the values of r ₁ and r ₃ , resulting in N _OUT /
Affects the N _IN gear ratio. To further explain the motion of the steel ball 21 with reference to FIG. 4, points A, B,
C, O are fixed in terms of ξηζ coordinates, but x
Viewed from the coordinates with one point on the axis as the origin, the drive cone 28 rotates the O point around the x-axis via the A point, and the rotation of the O point rotates the drive plate 35 around the x-axis via the B point. Rotate it. The number of rotations around the x-axis at point B is the same as the number of rotations around the x-axis at point O. When point O rotates around the x-axis, steel ball 2
Since the outer ring 22 that is in contact with the outer ring 1 at the point C is fixed, the steel ball 21 is rotated about B-O through the point C. Drive plate 3
5's rotation speed N _OUT (equal to the rotation speed at point O), the rotation speed at point A is N _OUT (r ₁・R ₃ )/
R ₁・r ₃ , and the rotation speed N _IN around the x-axis at point A is
Since it is the sum of N _OUT and the number of rotations of the steel ball 21 at point A, equation (2) holds true. The semicircular groove 35a of the output side drive plate 35 is shown in FIGS. 5 to 7.
As shown in the figure, the shape is such that it can come into contact with the surface of the steel ball 21 at one point in the expected range of change of the center position O of the steel ball 21 with respect to the coordinate axis with the origin at a point on the x-axis, and at the contact point B, the steel ball The steel ball 21 is pressed against the drive plate 35 with a large pressing force to prevent it from slipping, and the steel ball 21 rotates around the point B and rotates on its axis, applying torque to the drive plate 35 and rotating the output shaft 10. As described above, in this invention, the three
By configuring the input shaft drive cone, outer ring, and semicircular groove of the output side drive plate so that the center of rotation of the steel ball is automatically determined by the equilibrium of point forces, the number of parts is small, the structure is simple, and the cost is low. It is possible to provide a continuously variable transmission device that can be manufactured, is small, and has a long life. Note that even if the input and output shafts are reversed, the operation is the same except that the gear ratio is reversed. It can be operated in either the left or right direction of rotation.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view showing a conventional device, FIG. 2 is an explanatory diagram explaining the operation of the device shown in FIG. 1, FIG. 3 is a partial cross-sectional view showing an embodiment of the present invention, and FIG. 5 is a front view of the output side drive plate, FIG. 6 is a sectional view thereof, and FIG. 7 is a circumferentially developed sectional view thereof. 6... Housing, 7, 8... Bracket, 9
...Input shaft, 10...Output shaft, 17...Lubricating oil,
18, 19...Oil seal, 21...Steel ball, 2
2...Outer ring, 28...Input side drive cone, 35...Output side drive plate, 35a
...Semilunar groove. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A first rotation axis, which has its centers at points equidistant from the x-axis in a plane perpendicular to the x-axis, when the axial direction of the first rotation axis is the x-axis, and has a center-to-center distance. A plurality of spheres having the same shape as each other uniformly arranged, and a first rotating shaft that accommodates the plurality of spheres and is rotatable about the x-axis and fixed in position in the x-axis direction. a housing structure that is fixed to this housing structure and has one side whose cut surface by a plane including the x-axis is a tangent to the sphere, and a change in the distance of the center position O of the sphere from the x-axis; an outer ring configured to change the contact position C between the one side and the sphere; and an outer ring configured to be slidable in the x-axis direction with respect to the first rotation axis and configured to rotate around the x-axis as described above. It has an axis fixedly connected to the first rotation axis, and a cut surface by a plane including the x-axis maintains one-point contact with the outer periphery of the sphere, and the contact point A is at the x-axis with the center of the sphere. A drive cone that has a concave curved shape determined by the relative position in the axial direction,
A cross section taken by a plane including the x-axis maintains one point contact on the outer periphery of the sphere at a point opposite to the contact point with the outer ring and drive cone, and the contact point B is the x-axis at the center position O of the sphere. The drive plate has a semicircular groove with a concave curve that changes depending on the distance from Adjusting the relative position in the x-axis direction between a second rotating shaft that is freely movable and fixed at a position opposite to the first rotating shaft in the x-axis direction, and the first rotating shaft and the drive cone. means for adjusting the distance of the center position O of the sphere from the x-axis, and the rotation angle at which the drive cone rotates the sphere around the x-axis via the contact point A is adjusted to the center position of the sphere. The rotation angle of the drive plate around the x-axis through the contact point B due to the rotation of O around the x-axis, and the rotation angle of OB generated by the rotation of the above-mentioned position O because the contact point C is fixed. A continuously variable transmission characterized in that the relationship between the rotation speed of the drive cone and the rotation speed of the drive plate is determined by dividing the rotation angle at point A of the rotation of a sphere.