JPH0460245A - Continuously variable transmission - Google Patents

Abstract

PURPOSE:To automatically change speed steplessly without high-priced parts and electrical control by displacing a speed change ring in its axial direction using a cam having an inclined face at the end surface and a spring for displacing the cam according to the load of an output shaft. CONSTITUTION:During no-load of an output shaft 26, a bearing 40 is forced to press an inclined face 4a by a spring 45 to clamp a portion of a cam 39, which has the minimum axial thickness, to support the cam. In such a condition, the output shaft 26 can be rotated at high speed by suitably setting the positional relationship of a speed change ring 38 to a cone 32. When load is applied to the output shaft 26, the rotating force produced by the load is transmitted from the cone 32 to the speed change ring 38 to produce the rotating force in the cam 39. The rotating force is equal to the load torque in magnitude and opposite in direction. Whereupon, an inclined face 49 of the cam 39 displaces the bearing 40 against the spring 45, so that the cam 39 is rotated and displaced in the axial direction. Thus, the contacting position between the speed change ring 38 and the cone 32 is changed to attain a suitable speed change ratio.

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a continuously variable transmission, and in particular, it is attached to the outer periphery of a rotating body, and 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 rotation 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. 6, which automatically changes the gear ratio according to torque. Here, 1 is an input shaft, 2 is an output shaft, and both shafts l and 2 are arranged on the same axis, and an input side rotating disk 3 and an output side rotating disk 4 are attached to each shaft end. A cone retainer 5 is provided between the two rotary 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 3.4.

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 motor 11 connects a binion 10 that meshes with the rack 9.
It is said that it can be driven by 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 a differential movement.The motor 11 moves the speed change ring 7 so that the speed change ring 7 comes into contact with the cone 6 near the tip of the cone 6. For example, the amount of rolling of the cone 6 becomes smaller, the amount of differential motion becomes smaller, and the gear ratio becomes smaller.On the other hand, if you move the gear ring 7 so that it touches the hem of the cone 6, the rolling of the cone 6 becomes smaller. As the amount increases, the amount of differential motion also increases,
The gear ratio becomes larger.

In the automatic transmission mechanism shown in FIG. 6, the rotation speed of the output shaft 2 is detected by a sensor 12, and changes in the rotation speed due to increases and decreases in load are fed back to the motor 11 by a control device 13 to perform speed changes.

7 and 8 show other conventional automatic transmission mechanisms,
Here, a swing arm 15 whose one end is supported by the machine frame is provided, and the tip of this swing arm 15 is connected to the speed change ring 7. It can also be attached to the gear shift ring 7 or the retainer 16.
A compression spring 17 is provided between the machine frame and the machine frame.

According to such a configuration, the speed change ring 7 is guided by the rotation of the swing arm 15 and is movable in both the axial direction and the circumferential direction.

FIG. 7 shows a case where the load on the output shaft 2 is small.

When the retainer 16 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 the spring 17 is compressed and deformed by this rotational force 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 automatic transmission mechanism shown in FIG. 6 requires electricity for control, and also requires a motor 11, a rotation sensor 12, etc., making it expensive. There is a problem with this.

Furthermore, the conventional automatic transmission mechanism shown in FIGS. 7 and 8 has a problem in that it can only be used for rotation in one direction due to its structure.

Therefore, in order to solve the above-mentioned problems of the conventional device, the present applicant has already proposed the device shown in Japanese Patent Application No. 1-324364.

That is, as shown in FIG. 9, the end surface of the cam 18 has a V-shaped inclined surface 18A with inclined parts 18a and 18b which are inclined in opposite directions so that the thickness in the axial direction gradually changes.
A speed change ring 7 is attached to the inner peripheral surface of this cam 18, and this speed change ring 7 is displaced in the circumferential direction together with the cam 8 due to differential movement of a cone and a rotating body (none of which are shown). Both end faces of the cam 18 are supported by poles 19A and 19B of a bearing 19 that is in contact with both end faces and the cam 18 is sandwiched between them, and the poles 19A and 19B of the bearing 19 are supported by the cam 18.
A spring 20 is provided to press both end faces of the spring 20.
Accordingly, the shift ring 7 is allowed to be displaced in the circumferential direction according to the magnitude of the load on the output shaft, and the shift ring is configured to be displaced in the axial direction by the inclined surface due to this circumferential displacement. As a result, an appropriate gear ratio based on the load torque can be obtained without using an external control device, and the V-shaped inclined surface 18A of the cam 18 allows for not only forward rotation but also reverse rotation. becomes.

However, in the above case, since the inclined surface 18A of the cam 18 is V-shaped, the startup is smooth when moving from the minimum gear ratio position shown by the solid line in Fig. 1O to the maximum gear ratio position shown by the chain line. However, since special machining is required to form the inclined surface 18A, the machining process is time-consuming and costly.

Therefore, the present invention solves these problems and makes it possible to obtain an appropriate gear ratio without the need for a special electrically controlled device such as a motor or sensor to move the gear ring in the axial direction. and can be used for rotation in both forward and reverse directions.
In particular, it is an object of the present invention to provide an inexpensive continuously variable transmission that can provide a smooth response to the start of a shift operation.

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. A single inclined surface is formed on one end surface of the cam to gradually change the thickness in the axial direction of the cam, and both end surfaces of the cam are configured to be movable.
The cam is supported by bearings that are in contact with both end faces and sandwich the cam between them, and a spring is provided that presses the bearing against both end faces of the cam. This displacement in the circumferential direction causes the inclined surface to displace the speed change ring in its axial direction.

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 equal in magnitude and opposite in direction to the load torque.

Then, the cam rotates as the inclined surface pushes the bearing away from the spring, and the cam is displaced in the direction of its axis by the reaction force of the inclined surface pushing the bearing. 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.

Furthermore, since the inclined surface of the cam can accommodate both forward and reverse rotations of the input shaft, the same automatic gear change can be performed in both directions, and moreover, the gear ratio can be shifted from the minimum gear ratio position to the maximum gear ratio position. Since the change in angle of the inclined surface is small, the shift can be started smoothly.

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 shaft 25 is attached to the bevel gear 24 in a direction perpendicular to the input shaft 21. Inside the case 23 is an output shaft 26 arranged so that its axis coincides with the second shaft 25.
It is supported so as to be rotatable independently of the . The end of the output shaft 26 protrudes outward from the case 23.

The end portion 27 of the second mountain shaft 25 is formed into a brim 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 input disk 28 is supported by a meshing clutch 29 that does not perform disconnection. , the end 27 of the second human mountain axis 25
is connected to. A cone retainer 31 is arranged concentrically on the outer periphery of the output shaft 26 following the input disk 28 and is configured to be rotatable.
A plurality of cones 32 are rotatably provided. This cone 32 has an outer peripheral flange 33 formed on the input disk 28.
Frictional transmission occurs between the

An output disc 34 is provided concentrically on the outer periphery of the output shaft 26, and the output disc 34 is integrated into the cone retainer 31.
performs frictional transmission between its outer periphery and the cone 32,
The output disk 34 is connected to a sleeve 36 via a pole 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 31 and around which the cone 32 is attached.
2, and is fixed to a cylindrical cam 39 shown in FIG. 2 and can rotate together with the cylindrical cam 39. 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 pawls 41 and 42 that sandwich both end surfaces in the axial direction of the cam 39, a fixed retainer 43 that removably accommodates one pawl 41, and a movable retainer 43 that removably accommodates the other pawl 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 bearing 47 formed in the case 23 in a direction parallel to the axis of the cam 39 .

48 is an adjustment screw.

By pushing the fixed retainer 43 and changing its position, the pressing force generated by the spring 45 and the like can be adjusted.

An end cam is used as the cam 39,
An inclined surface 49 is formed on the end surface of the cam 39 that is in contact with the pole 41 of the fixed retainer 43. As shown in FIG. 3, this inclined surface 49 is a single inclined surface that gradually changes the thickness of the cam 39 in the axial direction.

In such a configuration, when rotation is applied to the input shaft 21, this rotation is transmitted to the second human 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. 6 to 8, and the rotation resulting from this gear change appears on the output shaft 26.

Now, both poles 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 pawl 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 surface 49 is in contact with the pawl 41 of the fixed retainer 43, the cam 39 rotates in the circumferential direction so that the inclined surface 49 pushes away the pawl 42 against the force of the spring 45, and eventually pushes the spring 45 away. While being compressed, it is displaced in the direction away from the fixed retainer 43 in the axial direction thereof. This displacement corresponds to the guide rod 4 of the movable retainer 44.
6 is fitted into the guide bearing 47, this is done smoothly.

As a result, the contact position between the speed change ring 38 and the cone 32 is displaced to the hem of the cone 32.

Then, based on the load torque, the slope 49 is adjusted to the pole 41.
The force pressing the spring 4 increases due to the displacement of the cam 39.
The mechanism becomes stable at the position where the force 5 is balanced, and the gear ratio becomes appropriate 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 pawl 41, and since the cam 39 and the pawl 41 only make point contact, the influence of the shape of the cam 39 in the thickness direction is prevented. Slope 4
By increasing the inclination angle 9, it is possible to improve the speed change 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.

Further, at the single inclined surface 49 of the cam 39, the cam 39
From the part 49c with the minimum thickness in the axial direction to the opposite sides of the part 49c, there are sloped parts 49a and 49b in opposite directions. It is possible to change gears.

Furthermore, the single inclined surface 49 of the cam 39 has a gentle inclination angle from the part 49c where the axial thickness of the cam 39 is minimum to the inclinations (149a, 49b) on both sides thereof. The start-up when starting the speed change operation from the position of the minimum speed change ratio shown in the figure can be performed without difficulty.

Furthermore, since the single inclined surface 49 of the cam 39 can be formed by a plane cutting method, it is easy to process and can be manufactured at low cost.

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.

In particular, by forming a single inclined surface on the end face of the cam, it is possible to smooth the start of the speed change operation, and also to facilitate manufacturing and reduce costs.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a continuously variable transmission according to an embodiment of the present invention, and FIG.
The figure is a half-cut sectional view showing the cam in Figure 1, Figure 3 is a perspective view of the main parts in Figure 1, Figures 4 and 5 are explanatory diagrams of the operation of the main parts in the same continuously variable transmission, respectively. 6 is a schematic diagram of a conventional automatic transmission mechanism, FIGS. 7 and 8 are schematic diagrams of other conventional automatic transmission mechanisms, and FIGS. 9 and 10 are cams each having a V-shaped inclined surface. FIG. 2 is a perspective view of the main parts of a continuously variable transmission using the same, and an explanatory diagram of its operation. 21...Input shaft, 25...Second human power shaft, 26...
Output shaft, 32... Cone, 32... Shift 1 non-stop,
39...Cam, 40...Bearing, 45...i
fne, 49...single slope.

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 retardation; The speed change ring is attached to the cam so that it can be displaced in the circumferential direction of the cam along with the differential movement of the cone and the rotating body, and the axial thickness of the cam is gradually increased on the end surface of the cam. forming a single inclined surface that changes the shape of the cam, supporting both end surfaces of the cam with bearings that are in contact with these end surfaces and sandwiching the cam therebetween, and providing springs that press the bearings against both end surfaces of the cam. The spring allows circumferential displacement of the speed change ring in accordance with the magnitude of the load on the output shaft, and this circumferential displacement causes the slope to displace the speed change ring in its axial direction. A continuously variable transmission characterized by: