JPH0541853B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) This invention relates to a friction transmission device used in a part that transmits power by changing speed from a driving shaft side to a driven shaft side, such as an automobile transmission. In particular, it relates to a friction transmission device that can be easily reversed forward and backward.

(Prior Art) Conventionally, gear mechanisms have been generally used in transmissions for large vehicles such as automobiles, especially trucks.

Furthermore, in recent years, some transmissions have been used that use torque converters in order to facilitate gear shifting operations.

However, in the case of transmissions using the gear mechanism or torque converter, transmission efficiency is poor and noise is generated, so recently transmissions using traditional friction transmission devices, which do not have the above problems, are being used again. Attention has been paid.

Regarding such friction transmission devices, there are, for example, the prior art of JP-A-62-147159, JP-A-62-31223, and JP-A-61-103054.

As shown in FIG. 10, the friction transmission device disclosed in JP-A No. 62-147159 has a
A friction plate 2' constituted by a rotating body whose ridgeline H is a quadratic curve on the side surface, and a driven shaft 3' fixed coaxially with the driving shaft 1', facing the friction plate 2'. Friction plates 2'' of the same shape are fixed, and a plurality of rollers 4' are installed between the friction plates 2' and 2''.
is rotatably arranged around its rotation center axis 4a'. By tilting the rotation center axis 4a' of this roller 4' in a plane including the longitudinal direction and normal direction of the driving shaft 1' or driven shaft 3', the roller 4' comes into contact with the friction plate 2'. radius to
The rotation ratio to be transmitted is changed by changing the radius difference between R' and the judgment r' where the roller 4' contacts the friction plate 2'', and the rotation ratio is changed from the driving shaft 1' side to the driven shaft 3' side. and is configured to transmit power.

Furthermore, the friction transmission device disclosed in Japanese Patent Application Laid-open No. 62-31223 is also configured to be able to change speed using basically the same mechanism as that in Japanese Patent Application Laid-open No. 62-147159.

As shown in FIG. 11, the friction transmission device disclosed in JP-A No. 61-103054 has two friction elements fixed to a driving shaft 1' on the back surface 4b' of a conical umbrella-shaped roller 4'. The plates 2A' and 2B' are selectively brought into contact with each other by a clutch 6', and the plate is attached to the conical surface 4c' of the roller 4' so as to be movable in the axial direction on the driven shaft 3' (coaxially with the driving shaft 1'). ring-shaped friction plate 2
By bringing the inner surfaces of C' into contact with each other and moving the friction plate 2C' along the conical surface 4c' of the roller ₄ ', the friction plate 2A', radii R ₁ ′, R ₂ ′ of 2B′ to the point where it contacts the roller 4′, and radius of the friction plate 2C′ to the point of contact with the roller 4′ with respect to the rotation center axis 0 ₃ ′ of the driven shaft 3′. r', and the radius R ₁ '', R ₂ '' of the friction plates 2A', 2B' to the position where they contact the roller 4' with respect to the rotation center axis 4a' of the roller 4', and the rotation center axis 4a' of the roller 4'. roller 4' of friction plate 2C' against
The rotation ratio transmitted from the driving shaft side to the driven shaft side is changed depending on the variable radius r'' up to the contact position.

(Problem to be solved by the invention) However, in the case of the former (Japanese Patent Application Laid-Open No. 62-417159, Japanese Patent Publication No. 62-31223), if the rotation on the driving shaft side is unidirectional, the rotation on the driven shaft side is also The disadvantage is that rotation can only be conducted in one direction.

Therefore, in this device, it is necessary to separately attach a forward/reverse mechanism to the transmission.

In the case of the latter (Japanese Patent Laid-Open No. 61-103054), although forward and reverse rotation can be transmitted, it is necessary to select either of the two friction plates 2A' and 2B' to change the speed depending on the speed range. Therefore, there is a problem that the device becomes complicated and that there is an instantaneous step when switching between the two friction plates 2A' and 2B'.

The present invention was made in view of the above-mentioned current situation.
It is an object of the present invention to provide a friction transmission device that does not have the above-mentioned disadvantages.

(Means for Solving the Problems) A friction transmission device according to the present invention includes two friction plates whose friction contact surfaces face each other on the driving shaft side and the driven shaft side, and transmits rotation between the two friction plates. In a friction transmission device in which a rotatable roller is interposed, the central axes of rotation of the two friction plates are arranged parallel to each other and offset, and the center of rotation of the roller is aligned with the central axis of rotation of one of the friction plates. The roller is arranged so as to be located above the roller, and the rotation center axis of the roller is configured to be tiltable within a plane in which the rotation center axes of the two friction plates exist, and the rotation center axis of the roller is configured to be tiltable within a plane in which the rotation center axes of the two friction plates exist. Either one of the surfaces is formed into a flat plate shape (in this specification, the concept includes a curved plate shape having a large radius of curvature), and
A curved surface having a semicircular cross section equal to the locus drawn by the outer edge of the roller when the roller tilts and a ring shape in plan view is formed on the other surface, and the outer peripheral edge of the roller has a curvature. It is characterized by a border that looks like this.

(Function) Therefore, the friction transmission device configured as described above functions as follows. In order to make it easier to understand the operation of the device according to the present invention, it will be explained using FIG. 3 or FIG. 4 showing the basic configuration of the present invention. The rotation center axis 4a of the roller 4 is connected to the friction plates 2A, 2.
By tilting the roller 4 around the tilting center point 0 ₂ in the plane where the rotation center axes 0 ₁ and 0 ₃ of B exist (the plane corresponding to the paper surface in the figure),
Contact point A between roller 4 and both friction plates 2A, 2B,
As a result of B moving in the radial direction on the friction plate, the contact point A of the roller 4 on one friction plate 2A
Distance from to the rotation center axis 0 ₁ of the friction plate 2A
An arbitrary speed ratio i can be obtained from the relationship between R ₁ and the distance r ₁ from the contact point B of the roller 4 on the other friction plate 2B to the rotation center axis 0 ₃ of the friction plate 2B. That is, the gear ratio i is expressed by the following formula.

i=n ₃ /n ₁ =0 ₁ A/0 ₃ B×0 ₂ B/0 ₂ A≒0 ₁ A/0 ₃ B…
...(1) (However, n ₁ and n ₃ are the rotational speeds of the driving shaft and driven shaft.) Now, the point where the rotation center axis 4a of the roller 4 and the center of the roller in the width direction intersect is O, and the curvature of the outer peripheral edge of the roller The center point of is O', the distance from O to B is R,
If the distance from O' to B is r, then "0 ₁ A" and "0 ₃ B" in the above equations are expressed by the following equations in the case of the configuration shown in FIG.

0 ₁ A=(R-r)sinα ……(2) 0 ₃ B=l+Rsinα ……(3) Therefore, from the above equations (2) and (3), equation (1) becomes the following equation (4). It is expressed as follows.

i≈(R−r)sinα/l+Rsinα (4) Furthermore, in the case of the configuration shown in FIG. 4, it is expressed by the following equation.

0 ₁ A=(2R−r)sinα ……(2)′ 0 ₃ B=l ……(3)′ Therefore, from the above equations (2)′ and (3)′, equation (1) becomes the following ( 4) It is expressed as follows.

i≒(2R−r)sinα/l ……(4)′ From equation (4) or (4)′ above, in which direction should the roller be tilted from the state with no tilting angle (the state where α = 0)? It can be seen that forward rotation or reverse rotation can be obtained arbitrarily, and that the larger the tilting angle, the greater the gear ratio.

That is, when the rotor 4 is tilted in the state (direction) indicated by the solid line in FIG. 3 or 4, the rotation direction of transmission from one friction plate 2A to the other friction plate 2B is in the same direction, As the angle α increases, the rotation ratio (speed ratio) increases, and as the tilting angle α decreases, the rotation ratio decreases.

On the other hand, when it is tilted in the opposite direction to the above-mentioned direction (see the two-dot chain line in Figure 4), one friction plate 2A rotates in the opposite direction to the other friction plate 2B, and the tilting angle α is changed. The larger the tilt angle α, the larger the rotation ratio, and the smaller the tilt angle α, the smaller the rotation ratio.

Therefore, as described above, by simply changing the tilting direction and tilting angle of the roller, it is possible to transmit in any direction and at any rotation ratio.

(Example) Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a skeleton diagram showing the configuration of the main parts of the friction transmission device according to this embodiment, FIG. 2 is a plan view showing the specific configuration of the friction transmission device in FIG. 1, and FIG. FIG. 2 is a skeleton diagram showing the most basic (simple) configuration of the device.

In FIGS. 1 and 2 showing the first embodiment, 1
is a driving shaft, 2A is a friction plate attached to the driving shaft 1 side, 2B is a friction plate attached to the driven shaft 3 side so that its friction contact surface faces the friction plate 2A, 4 is the friction plate 2A, This is a roller interposed between 2B. The friction plates 2A, 2B and the roller 4 are made of carburized and hardened steel in this embodiment. and,
The rotation center axis of the friction plate 2A, that is, the rotation center axis ₀₁ of the driving shaft 1, and the rotation center axis of the other friction plate 2B, that is, the rotation center axis ₀₃ of the driven shaft 3, are separated by a distance l (see Fig. 1). are arranged on parallel axes offset by .

Further, the roller 4 has a tilting center point 0 ₂ (the point where the rotation center axis 4a intersects the center in the width direction in this embodiment) with a rotation center axis 0 ₁ of one friction plate 2A.
The rotation center axis 4a of the roller 4 is configured to be freely tiltable within a plane in which the rotation center axes 0 ₁ and 0 ₃ of the friction plates 2A and 2B exist. Specifically, as shown in FIG.
The above tilting center point ₀₂ of the roller 4 is connected to the shaft 4 via b.
c is pivotally supported by the support frame 10, and the rotation center shaft 4a is externally driven by a known tilting drive means (not shown) such as a cam.
It is configured so that it can be tilted. In this case, as shown in FIGS. 1 and 2, there may be a plurality of rollers 4 (in the case of FIGS. 1 and 2, two or four rollers).
If two or more are installed, they must be configured so that they can tilt by the same angle in synchronization.

As for the opposing surfaces (contact surfaces) of the friction plates 2A and 2B, one of the friction plates 2A has a flat surface 2a, and the other friction plate 2B has a ring-shaped curved surface 2b. This curved surface 2b has a cross-sectional shape as shown in FIG _.
It is formed in a semicircle with the center point.

On the other hand, the outer peripheral edge 4d of the roller 4 is hemmed with a curvature whose diameter is the width of the roller.
By the way, in FIGS. 1 and 2, 5 is an output shaft on the motor side, 6 is a clutch mechanism for connecting and connecting the output shaft 5 and intermediate shaft 7, and 7 is a mechanism that rotates on the driving shaft 1 via a pair of gears 8. It is an intermediate shaft for transmitting force. Further, reference numeral 9 denotes a pressing mechanism configured to be able to move the friction plate 2B in the axial direction of its rotational center axis ₀₃ and to press it with a desired axial force (force in the axial direction). In this case, a pressing piston 15 presses the friction plate 2B toward the roller 4 with a constant axial force.
(See FIG. 3) and a return spring 11 that urges against the pressure of the hydraulic piston 15.

In the case of the pressing mechanism with the above configuration, if fine control or adjustment of the pressing force is possible, or if the structure is to be simplified, a friction plate (not shown) may be pressed instead of the pressing mechanism with the above configuration. The roller is supported on an inclined surface (cam surface), and a torsion spring is inserted between the member having this inclined surface and the fixed side to bias the roller (with preload applied), thereby suppressing torque fluctuations. It may be configured to mechanically apply a thrust in the axial direction according to the magnitude of the generated torque in correspondence with the axial positional relationship due to the elastic force of the torsion spring and the inclination of the slope.

Further, the support frame 10 of the roller 4 has a bearing 12 rotatably supported at the tip of the driven shaft 3, which is the rotation center axis ₀₃ .

When power is transmitted through friction, it works as follows.

That is, the rotation center axis 4a of the roller 4 is connected to the friction plate 2.
In the state perpendicular to the rotation center axes 0 ₁ and 0 ₃ of the friction plates A and 2B, the roller 4 contacts the friction plate 2A at the rotation center axis 0 ₁ of the friction plate 2A.
The roller 4 does not rotate, and rotation from the driving shaft 1 side is not transmitted to the roller 4.

Then, when the rotation center shaft 4a is tilted about the tilt center axis point ₀₂ of the roller 4, for example, in the state shown in FIG. 1 or FIG. 2, the friction plate 2A
and the distance R from the contact point A of the roller 4 to the rotation center axis ₀₁ of the friction plate 2A (see FIG. 3), and
Rotation is transmitted from the driving shaft 1 to the driven shaft 3 by the distance r (see FIG. ₃ ) from the point of contact B between the roller 4 and the rotation center axis 0 3 of the friction plate 2B. In this case, the rotation direction of the driven shaft 3 is the same as that of the driving shaft 1, and the rotation ratio i is i=R/r. As shown in FIG. 5, as the tilting angle of the roller 4 is gradually increased, the rotation ratio i becomes gradually larger.

Furthermore, if the roller 4 is tilted in the opposite direction to the above case, the driven shaft 3 rotates in the opposite direction to the driving shaft 1. Also in this case, if the tilting angle is gradually increased, the rotation ratio i will gradually increase. Therefore, in this friction transmission device, if l = R and O'B = 0, then
The rotation ratio i can be changed within the range of +1/3 to -1/1. Further, the values of "+" and "-" can be reversed by combining the pair of gears.

By the way, in this first embodiment, when the rotational center axis 4a of the roller 4 is tilted, the tilting center point ₀₂ is at the intersection O of the rotational center axis 4a and its widthwise center as described above, and this tilting By tilting around the center point ₀₂ , the length of the driving shaft or driven shaft of the roller 4 in the axial direction changes. The relative position of the friction plate 2B changes. However, in this embodiment, the driven shaft 3 having the friction plate 2B is moved by the same length (distance) as the change in the axial direction according to the change by the above-described pressing mechanism. Since this change can be accommodated and the axial direction is kept constant even with the movement in the axial direction, frictional transmission can be performed without any problems.

Furthermore, in this embodiment, the outer peripheral edge of the roller 4 is edged with a curvature of a diameter equal to the width of the roller 4, and the cross-sectional shape of the curved surface 2b of the friction plate 2B is centered around the center O of the roller. Since the curved surface 2b has a larger curvature than the curvature of the roller 4, the roller 4 and the friction plate 2B are in line contact (the first
(point contact in the side view of FIG. 2), and the rotation ratio can be smoothly changed according to the tilting movement of the roller.

The basic structure (idea) of this first embodiment is shown in the friction transmission device shown in FIG.
However, in practice, from the viewpoint of conduction capacity, it is preferable to use a configuration in which a plurality of rollers are interposed, such as the device shown in FIGS. 1 and 2 described above.

Further, as another embodiment (referred to as a second embodiment) of the present invention, the same effect can be obtained even if the structure is configured as shown in FIG. 4.

That is, unlike the embodiments described above, in this embodiment, a ring-shaped frame curved surface 2b is formed on the contact surface of the friction plate 2A, and the contact surface of the friction plate 2B is formed with a flat surface 2.
It is formed in a.

Then, the center point O' of the semicircle forming the outer peripheral edge of the roller at the center in the width direction of the roller is located at the friction plate 2A.
is located on the rotation center axis 0 ₁ of , and this center point
The structure is such that O' coincides with the tilting center point 0 ₂ of the roller 4. Also in the case of this embodiment, the curved surface 2b of the friction plate 2A is formed into a semicircle with the tilting center point 0 ₂ as the center point.

Therefore, in the case of this embodiment, even if the roller 4 is tilted, the distance between the friction plates 2A and 2B does not change. Rotation center axis 0 ₃ (driven axis)
There is no need for a pressing mechanism that can guide the movement along the roller 4, and a pressing mechanism such as a hydraulic piston 15 that presses the friction plate 2B toward the roller 4 with a constant pressing force is sufficient.
Note that the reference numbers in FIG. 4 indicate the same ones as in FIGS. 1 and 2.

By the way, the roller 4 in the above two embodiments
For example, when there are two rollers 4 in the embodiment shown in FIG. 2, the tilting mechanism tilts the rollers from the state shown in FIG.
As shown in FIG. 6, which is a view in the direction of FIG. 6, or FIG. 7, which is a view in the direction of FIG.
b, and this shaft 4c is supported by the support frame 10 via a bearing. A link 103 having a bifurcated tip is fixed to one end of the shaft 4c, and as shown in FIG. The bent slit portions 103a (see FIGS. 7 and 9b) are overlapped with each other with different heights, and the roller 4 is tilted into the opening hole 104 formed by these two opposing slit portions 103a. A pin 105 is inserted. As shown in FIG. 6, the base end of this pin 105 is inserted into a guide groove 106a (see FIG. 9c) of a guide groove member 106 arranged parallel to the rotation center axis ₀₃ of the friction plate 2B. The tip of the pin 105 swings (rotates) around the support pin 108 on the support frame 10.
Elongated hole 109 of freely arranged operating lever 109
a (see Figure 9e).

Then, the operation lever 109 is moved to the support pin 10.
8, the pin 105 is moved linearly in the X direction along the guide groove of the guide groove member 106, changing from the state shown in FIG. 7 to the state shown in FIG. In addition, the roller 4 can be tilted at an arbitrary angle (for example, a tilting angle α). Furthermore, if the pin 105 is linearly moved in the Y direction in FIG. 7 using the operating lever 109 and tilted in the opposite direction to that shown in FIG. 8, rotation can be transmitted in the opposite direction to that shown in FIG. can. To help understand the tilting mechanism, FIGS. 9a to 9f show perspective views of the support housing 4b, the link 103, the guide groove member 106, the pin 105, the operation lever 109, and the support pin 108 of the operation lever 109. shows.

Further, in the above two embodiments, the contact surface of one of the friction plates is formed as a flat surface, but even if it is formed as a curved surface with a large radius of curvature, the effects of the present invention can be obtained. Therefore, when understanding the present invention, it should be understood that the phrase "planar" of the friction plate includes cases where the friction plate has a large radius of curvature.

(Effect of the invention) Since the present invention is configured as described above,
A plurality of rollers can be interposed between two friction plates having opposing contact surfaces, and therefore a large amount of force (rotational force) can be transmitted, and even with a simple configuration, it is possible to On the other hand, the driven shaft can be rotated in forward and reverse directions.

In addition, by simply tilting the rollers, the speed can be changed steplessly and smoothly from the maximum rotation ratio for forward rotation to the maximum rotation ratio for reverse rotation, and the speed change range is also within the range required for normal automobiles. can be sufficiently covered.

Furthermore, due to frictional conduction, it has extremely high mechanical efficiency and is quiet.

Therefore, when the friction transmission device according to the present invention is installed in an automobile, it can be used at low cost as a transmission device that is quiet, has a simple structure, is highly reliable, and is easy to operate.

Furthermore, since a plurality of rollers can be structurally interposed between two friction plates and the number can be appropriately changed depending on the transmission capacity, it can be easily applied as a transmission device for various vehicles.

[Brief explanation of the drawing]

FIG. 1 is a skeleton diagram showing the configuration of essential parts of a friction transmission device according to a first embodiment of the present invention, FIG. 2 is a plan view showing a specific configuration of the friction transmission device of FIG. 1, and FIG. The most basic (simple) device in Figure 1
FIG. 4 is a skeleton diagram showing the most basic configuration of an embodiment (second embodiment) different from that in FIG. FIG. 6 is a diagram showing the relationship between the tilting angle and the rotation ratio, and FIG. 6 shows the roller tilting mechanism of FIG. 2 with the roller tilted.
Figures 7 and 8 are views taken from the - arrow in Figure 6, Figures 9 a to f are perspective views of the main components of the tilting mechanism, and Figures 10 and 11 are conventional friction transmission FIG. 2 is a partial plan view showing the configuration of main parts of the device. 1... Driving shaft, 2A, 2B... Friction plate, 2a...
...Plane, 2b...Ring-shaped groove, 3...Driver shaft,
4...Roller, _01,03 ...Rotation center axis of friction plate, ₀₂ ...Roller _tilting center point, l...Offset amount.

Claims (1)

[Claims] 1. Two friction plates are arranged so that their friction contact surfaces face each other on the driving shaft side and the driven shaft side, and a rotatable roller that transmits rotation is interposed between the two friction plates. In the friction transmission device, the rotation center axes of the two friction plates are arranged offset in the form of parallel axes, and the roller is arranged so that the tilting center point of the roller is located on the rotation center axis of one of the friction plates. In addition, the rotation center axis of the roller is configured to be tiltable within a plane in which the rotation center axes of the two friction plates exist, and one of the opposing surfaces of the two friction plates has a flat plate shape. and a curved surface having a semicircular cross-sectional view equal to the locus drawn when the outer edge of the roller tilts and a ring-like planar view is formed on the other surface; A friction transmission device characterized in that an outer peripheral edge of the friction transmission device is edged to have a curvature.