JPH03186664A - Continuously variable transmission - Google Patents

Abstract

PURPOSE:To make an automatic variable transmission possible and a speed change similarly possible, even when an input shaft is rotated in both normal and reverse directions, by displacing a speed change ring in a direction of the axial center by means of a cam, having a tilt surface on the end face, and by means of a spring for displacing the cam in accordance with a load of an output shaft. CONSTITUTION:When a load is applied to an output shaft 26, turning force in proportion to load torque is transmitted from a cone 32 to a speed change ring 38 so as to try to rotate a cam 39 in the circumferential direction with the ring 38. Then the cam 39 is rotated in the peripheral direction, so that a tilt surface 49 pushes aside a ball 41 against tension of a spring 45, and displaced in a direction of the axial center so as to separate from a fixed retainer 43 while compressing the spring 45. Consequently, a contact position of the ring 38 with the cone 32 is displaced to its skirt, and in a position where pressing force of the tilt surface 49 to the ball 41, based on the load torque, is balanced with force of the spring 45 increased by the displacement of the cam, speed change ratio in accordance with a load is obtained by stabilizing a mechanism. Also, because the tilt surface 49 is provided with tilt parts 50, 51 in mutually reverse directions, a similar automatic speed change can be performed even when an input shaft 21 is rotated in any of both normal and reverse directions.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to a continuously variable transmission, and in particular to a continuously variable transmission that is attached to the outer periphery of a rotating body and that is in contact with both an input disk on the input shaft side and an output disk on the output shaft side. a plurality of cones that transmit rotation between these input and output shafts; a speed change ring whose inner periphery contacts each cone and causes differential movement of these cones and the rotating body; means for changing the rotational speed of the output shaft by moving it in the axial direction and changing the contact position between the speed change ring and the cone to adjust the amount of the differential movement; Concerning a continuously variable transmission.

Conventional Technology This type of continuously variable transmission is widely used as a means for smooth startup and speed control when transmitting power from electric motors and engines in equipment, machine tools, industrial machinery, etc. .

Conventionally, there is a continuously variable transmission as shown in FIG. 4, which automatically changes the gear ratio according to torque. Here, 1 is the input axis, 2 is the output axis,
Both shafts 1 and 2 are arranged on the same axis, and an input rotating disk 3 and an output rotating disk 4 are attached to the ends of each shaft.

A cone retainer 5 is provided between both rotating disks 3 and 4 so as to be rotatable about the same axis as these. A plurality of cones 6 are rotatably provided around the cone retainer 5, and the cones 6 perform frictional transmission with the outer peripheral edges of both rotating disks 3 and 4.

A speed change ring 7 is provided around the retainer 5 and around which the cone 6 is attached. That is, each cone 6 is arranged so that its ridge line is parallel to the rotation axis of the retainer 5,
The speed change ring 7 is configured such that its inner peripheral portion engages in frictional transmission with the conical portion of each cone 6 . The speed change ring 7 is fixed to the fork 8 and is configured not to move in the circumferential direction, but is movable together with the fork 8 in the axial direction. A rack 9 is attached to the fork 8, and a pinion 10 that meshes with the rack 9 is connected to the motor 1.
It is said that it can be driven at 1. A rotation sensor 12 detects the rotation speed of the output shaft 2. 13 is a control device.

According to such a configuration, since the speed change ring 7 is in contact with the cone 6, this cone 6 is rotated by the input side rotating disk 3 and rolls along the inner peripheral edge of the speed change ring 6, and this rolling Based on the movement, the retainer 5 and the cone 6 integrally perform differential movement. If the speed change ring 7 is moved by the motor 11 so that the speed change ring 7 comes into contact with the cone 6 near the tip of the cone 6, the amount of rolling of the cone 6 is reduced, and the amount of differential motion is also reduced. The gear ratio becomes smaller. On the other hand, if the speed change ring 7 is moved so as to come into contact with the resting part of the cone 6, the amount of rolling of the cone 6 will increase, and the amount of differential movement will also increase.
The gear ratio becomes larger.

In the transmission shown in Fig. 4, the rotation speed of the output shaft 2 is detected by the sensor 1.
2, and the change in rotational speed due to an increase/decrease in load is fed back to the motor 11 by a control device I3 to perform a speed change.

5 and 6 show other conventional continuously variable transmissions. Here, a swing arm I5 with one end supported by the machine frame is provided,
The tip of this swing arm 15 is connected to the speed change ring 7. Further, a compression spring 17 is provided attached to the speed change ring 7 or between the retainer 16 and the machine frame.

According to such a configuration, the speed change ring 7 is guided by the rotation of the swing arm I5 and is movable in both the axial direction and the circumferential direction.

FIG. 5 shows a case where the load on the output shaft 2 is small.

When the retainer 1G is pushed by the compression spring 17, the swing arm 15 turns, and the speed change ring 7 is positioned at the tip of the cone 6, so that the output shaft 2 rotates at high speed. When the load on the output shaft 2 increases in this state, the accompanying rotational force is transmitted from the cone 6 to the speed change ring 7, and this rotational force compresses and deforms the spring I7 as shown in FIG. Then,
Based on this, the speed change ring 7 moves in the circumferential direction, and the arm 15 pivots accordingly, so the speed change ring 7 moves in the axial direction so that the amount of differential movement increases. As a result, the output shaft 2 is decelerated according to the load, but the speed change ring 7 contacts the cone 6 at a position where the shaft load and the spring force are balanced.

Problems to be Solved by the Invention However, the conventional continuously variable transmission shown in FIG.
There is a problem that it becomes expensive because it requires 2 etc.

Further, the conventional continuously variable transmission shown in FIGS. 5 and 6 has a problem in that it can only be used for rotation in one direction due to its structure.

The present invention solves these problems and eliminates the need for special electrically controlled devices such as motors and sensors to move the speed change ring in the axial direction.Moreover, it can rotate in both forward and reverse directions. The purpose is to provide a continuously variable transmission that can be used.

Means for Solving the Problems In order to achieve the above object, the present invention provides the following: A speed change ring is attached to a cylindrical cam, and this speed change ring is moved in the circumferential direction of the cam along with the differential movement of the cone and the rotating body. The cam is configured to be displaceable, and the end face of the cam is formed with an inclined surface that gradually changes the thickness in the axial direction, and both end faces of the cam are connected to bearings that are in contact with the both end faces and sandwich the cam therebetween. A spring is provided to press the bearing against both end surfaces of the cam, and this spring allows circumferential displacement of the speed change ring in accordance with the magnitude of the load on the output shaft. , the speed change ring is configured to be displaced in the axial direction by the inclined surface.

In this configuration, when no load is applied to the output shaft, the bearing presses against the inclined surface due to the force of the spring, and the bearing supports the cam by sandwiching it at the part where the cam's axial thickness is minimum. do. By appropriately setting the positional relationship between the speed change ring and the cone, it is possible to rotate the output shaft at high speed in this state.

When a load is applied to the output shaft, the accompanying rotational force is transmitted from the cone to the speed change ring, generating rotational force on the cam, and this rotational force is proportional to the load torque. Then, the cam rotates as the inclined surface pushes the bearing away against the force of the spring, and due to the reaction force of this inclined surface pushing the bearing,
The cam is displaced in its axial direction. This changes the contact position between the speed change ring and the cone, and the mechanism stabilizes at a position where the bearing pressing force on the inclined surface based on the load torque and the spring force are balanced, resulting in an appropriate speed change ratio.

At this time, it becomes possible to apply only a force in the axial direction of the cam to the spring, thereby preventing the spring from collapsing in the lateral direction.

An inclined surface is formed corresponding to both the normal rotation direction and the reverse rotation direction of the cam, and the inclined surface is V-shaped or U-shaped when viewed from the side of the cam.
If it is shaped like a letter, it is possible to change gears not only in forward rotation but also in reverse rotation.

Embodiment In FIG. 1, 21 is an input shaft, and this input shaft 21
has a bevel gear 22 at its tip and is rotatably supported in a case 23. A bevel gear 24 that meshes with the bevel gear 22 is rotatably supported in the case 23, and a second human blade shaft 25 is attached to the bevel gear 24 in a direction perpendicular to the input shaft 21. In the case 23, an output shaft 26 whose axis is aligned with the second human blade shaft 25 is supported so as to be rotatable independently of the second human blade shaft 25.

The end of the output shaft 26 protrudes outward from the case 23.

The end portion 27 of the second blade shaft 25 is formed into a collar shape.

Further, an input disk 28 having a cylindrical portion 30 is rotatably supported around the output shaft 26 in the case 23, and this manual disk 28 is connected to the second It is connected to the end 27 of the human blade shaft 25. A cone retainer 31 is arranged concentrically on the outer periphery of the output shaft 26 following the human-powered disc 28 and is rotatably configured, and a plurality of cones 32 are rotatably provided on the outer periphery of the cone retainer 31. There is. This cone 32 performs frictional transmission with an outer peripheral flange 33 formed on the input disk 28.

An output disk 34 is provided concentrically on the outer periphery of the output shaft 26 following the cone retainer 3I.
performs frictional transmission between its outer peripheral edge and the cone 32.

The output disk 34 is connected to a sleeve 36 via a ball 35, and this sleeve 36 is fixed to the output shaft 26. Therefore, these output disk 34, sleeve 36, and output shaft 26 can rotate together. A spring 37 presses the output disk 34 against the cone 32 for frictional transmission.

A speed change ring 38 is provided around the retainer 5 and around which the cone 32 is attached.
It is fixed to a cylindrical cam 39 and can rotate with the cam 39 by friction. The cam 39 has both end surfaces in the axial direction supported by a plurality of bearings 40 in the circumferential direction.

Each bearing 40 includes a pair of balls 41 and 42 that sandwich both end surfaces in the axial direction of the cam 39, a fixed retainer 43 that removably accommodates one ball 41, and a movable retainer 43 that removably accommodates the other ball 42. It has a retainer 44. The movable retainer 44 is pressed against the cam 39 by a spring 45 having a compression coil structure, and the spring 45 is arranged in a direction parallel to the axis of the cam 39. Further, a guide rod 46 disposed inside the spring 45 is attached to the movable retainer 44, and this guide rod 46
It is slidably fitted into a guide hole 47 formed in the case 23 in a direction parallel to the axis of the cam 39. 4
Reference numeral 8 denotes an adjustment screw which can adjust the pressing force generated by the spring 45 by pushing the fixed retainer 43 and changing its position.

An inclined surface 49 is formed on the end surface of the cam 39 that contacts the balls 41 of the fixed retainer 43 . This slope 4
9 is formed to gradually change the thickness of the cam 39 in the axial direction, and a pair of inclined parts 50 and 51 that are inclined in opposite directions are formed to gradually change the thickness of the cam 39 in the axial direction. They are formed in a V-shape so that they are continuous with each other at the portion where the thickness is the minimum.

In such a configuration, when rotation is applied to the input shaft 21, this rotation is transmitted to the second human blade shaft 25 and the input disk 28 via the bevel gears 22.24.

Then, the gear change is performed in the same manner as in the case of FIGS. 4 to 6,
The rotation resulting from this gear change appears on the output shaft 26.

Now, both balls 41 and 42 in the bearing 40 are
Since the force of the spring 45 presses the cam 39 so as to sandwich it, when no load is applied to the output shaft 26, the ball 41 presses the inclined surface 49, causing the cam 39 to move in the axial direction as shown in FIG. This cam 3 is the part with the smallest thickness.
The cam 39 is rotated so as to support the cam 39. At this time, by arranging each member so that the speed change ring 38 is in contact with the vicinity of the tip of the cone 32, the output shaft 26 rotates at a high speed with a small speed change ratio.

When a load is applied to the output shaft 26, a rotational force proportional to the load torque is transmitted from the cone 32 to the speed change ring 38, which attempts to rotate the cam 39 in the circumferential direction together with the speed change ring 38. Then, since the inclined surfaces 49 are in contact with the balls 41 of the fixed retainer 43, the cam 39 rotates in the circumferential direction so that the four inclined surfaces push the balls 41 away against the force of the spring 45, and eventually the spring 45 is pushed away. While being compressed, it is displaced in the axial direction so as to separate from the fixed retainer 43. This displacement is caused by the guide rod 46 of the movable retainer 44
Since this is fitted into the guide hole 47, this can be done smoothly.

As a result, the contact position between the speed change ring 38 and the cone 32 is displaced to the stationary portion of the cone 32. The mechanism is stabilized at a position where the force of the inclined surface 49 pressing the ball 41 based on the load torque and the force of the spring 45, which increases due to the displacement of the cam 39, are balanced, and an appropriate gear ratio is achieved depending on the load. The state at this time is shown in FIG.

If this is the case, the cam 3 will be applied to the spring 45.
Since the force is only in the axial direction of the spring 45, the spring 45 is prevented from collapsing in the lateral direction. Further, the cam 39 is supported by the ball 35, and since the cam 39 and the ball 35 only make point contact, the influence of the shape of the cam 39 in the thickness direction is prevented. Slope 49
By increasing the inclination angle, it is possible to improve the shift followability to load fluctuations. Furthermore, by using the spring 45 having a compression coil structure, stable shifting characteristics can be obtained even under large loads.

The inclined surface 49 has inclined parts 50° 51 which are inclined in mutually opposite directions.
Therefore, the same automatic speed change can be performed when the input shaft 21 is rotated in both forward and reverse directions.

Effects of the Invention As described above, according to the present invention, the speed change ring is displaced in the axial direction using a cam having an inclined surface on the end face and a spring that displaces the cam according to the load on the output shaft. Therefore, not only can automatic stepless speed change be performed without the need for expensive parts or electrical control, but also the same speed change can be performed even when the input shaft rotates in both forward and reverse directions. can.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a continuously variable transmission according to an embodiment of the present invention, and FIG.
The figure is an exploded view of the cam in Figure 1, Figure 3 is an expanded view showing the state of the cam in Figure 2 when it rotates, Figure 4 is a schematic configuration diagram of a conventional continuously variable transmission, Figure 5 and FIG. 6 is a schematic diagram of another conventional continuously variable transmission. 21...Input shaft, 25...Second human power shaft, 26...
Output shaft, 32... Cone, 38... Speed change ring, 3
9...Cam, 40...Bearing, 45...Spring, 49...Slanted surface.

Claims (1)

[Claims] 1. A plurality of disks are attached to the outer periphery of the rotating body and are in contact with both the input disk on the input shaft side and the output disk on the output shaft side, thereby transmitting rotation between these input and output shafts. a cone; a transmission ring whose inner periphery contacts each cone to cause differential movement of these cones and the rotating body; and a transmission ring that moves the transmission ring in its axial direction, a means for changing the rotational speed of the output shaft by changing the contact position and adjusting the amount of the differential movement; The speed change ring is configured to be displaceable in the circumferential direction of the cam along with the differential movement of the cone and the rotating body, and the thickness of the axial direction of the end surface of the cam is gradually changed. A slope is formed, both end faces of the cam are supported by bearings that are in contact with both end faces and the cam is sandwiched therebetween, and a spring is provided that presses the bearing against both end faces of the cam, and the spring causes the output to be increased. The speed change ring is configured to allow circumferential displacement of the speed change ring according to the magnitude of the load on the shaft, and to cause the speed change ring to be displaced in the axial direction by the inclined surface due to this circumferential displacement. Continuously variable transmission.