JPS63259261A - Belt type continuously variable transmission - Google Patents

Abstract

PURPOSE:To control a rotating speed ratio and a belt tension simultaneously by moving a movable rotator of an intermediate variable pulley so as to balance the belt reaction force of a transmission belt pressed in a variable pulley on the primary side with the belt reaction force of a transmission belt pressed in a variable pulley on the secondary side. CONSTITUTION:The belt reaction force of a transmission belt 28 acting on the movable rotator 54 of an intermediate variable pulley 26 is decided by a thrust given to a variable pulley 22 on the primary side by a hydraulic cylinder 46 on the primary side by a hydraulic cylinder 46 on the primary side and the rotating speed ratio of a continuously variable transmission mechanism 18 at that time. The belt reaction force of a transmission belt 36 acting on the movable rotator 56 of an intermediate variable pulley 30 is decided by a thrust given to a variable pulley 34 on the secondary side by a hydraulic cylinder 48 on the secondary side and the rotating speed ratio of a continuously variable transmission mechanism 20 at that time. A preset rotating speed ratio can be obtained by movement of a slide member 58 until a position where these both reaction forces are equalized to each other and stop thereof at this position.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a belt-type continuously variable transmission, and more particularly to an improvement in a belt-type continuously variable transmission in which a plurality of continuously variable transmission mechanisms are connected in series.

Conventional technology A transmission belt has a pair of variable pulleys provided on a primary rotation shaft and a secondary rotation shaft, respectively, and a transmission belt that is wound around the pair of variable pulleys to transmit power. Conventionally, a continuously variable transmission mechanism is known in which the rotational speed ratio between the primary rotation shaft and the secondary rotation shaft is changed steplessly by changing the belt hooking diameter of the variable pulley.

For example, JP-A-52-98861, JP-A-56-
One example is the continuously variable transmission mechanism described in Japanese Patent Application No. 86258-5 or Japanese Patent Application No. 61-37571 previously filed by the applicant of the present application.

By the way, in such a continuously variable transmission mechanism, if the variable range of the rotational speed ratio is to be increased, the diameter of the variable boob must be increased, resulting in an inconvenience that the transmission becomes large. For this reason, a belt-type continuously variable transmission is being considered in which a plurality of such continuously variable transmission mechanisms are connected in series to increase the variable range of the rotational speed ratio without increasing the diameter of the variable pulley. For example, JP-A-6
The transmission described in Publication No. 0-184758 is one example, and includes a primary variable pulley provided on the +al primary rotating shaft, and (b) a secondary variable pulley provided on the secondary rotating shaft. and (d) intermediate variable pulleys provided in pairs on each of two or more intermediate shafts, in which the movable rotating bodies are connected and interlocked with each other so that the diameter of the Cl belt is increased or decreased in opposition to each other. A plurality of power transmission belts are wound between variable pulleys such as the above to transmit power, and power transmission between the primary rotation shaft and the secondary rotation shaft is performed via the intermediate shaft. connected in series as,
A plurality of continuously variable transmission mechanisms are constituted by a pair of variable pulleys and a transmission belt wound around them, and by changing the speed change state of the plurality of continuously variable transmission mechanisms, the primary rotation shaft and The rotational speed ratio with the secondary rotating shaft is changed steplessly.

Problems to be Solved by the Invention However, such conventional belt-type continuously variable transmissions do not change the speed change state of the continuously variable transmission mechanism by driving a movable rotating body of an intermediate variable pulley provided on an intermediate shaft. Therefore, the rotational speed ratio and the belt tension of the power transmission belt cannot be controlled at the same time, resulting in problems such as power loss due to excessive belt tension.

Means for Solving the Problems The present invention has been made against the background of the above circumstances.
The purpose is to simultaneously control the rotational speed ratio and belt tension in a belt-type continuously variable transmission in which a plurality of continuously variable transmission mechanisms are connected in series.

In order to achieve this object, the present invention provides the above-mentioned (
a) a primary variable pulley; (b) a secondary variable pulley;
(C) An intermediate variable boob and (d) a transmission belt, which are connected in series so that power transmission between the primary rotation shaft and the secondary rotation shaft is performed via the intermediate shaft. , a plurality of continuously variable transmission mechanisms consisting of a pair of variable pulleys and a transmission belt wound around them are configured, and by changing the speed change state of the plurality of continuously variable transmission mechanisms, the primary rotation shaft A belt-type continuously variable transmission that steplessly changes the rotational speed ratio between the rotational speed of the primary side variable pulley and the secondary rotating shaft, (f) a secondary hydraulic cylinder that applies a thrust for compressing the transmission belt to the secondary variable boob; (gl) a primary hydraulic cylinder and a secondary hydraulic cylinder; control means for changing the speed change state of the continuously variable transmission mechanism by respectively controlling the magnitude of the thrust by the variable transmission mechanism, and the movable rotating body of the intermediate variable pulley is pinched by the primary variable pulley. The intermediate shaft can be freely moved in the axial direction of the intermediate shaft so that the belt reaction force of the transmission belt is balanced with the belt reaction force of the transmission belt compressed by the secondary variable pulley. It is characterized by the presence of

Function and Effects of the Invention In such a belt type continuously variable transmission, the magnitude of the thrust applied to the primary variable pulley and the secondary variable boolean by the primary hydraulic cylinder and the secondary hydraulic cylinder is controlled. By being controlled by the respective means, the movable rotating body of the intermediate variable pulley is moved in the axial direction of the intermediate shaft so that the belt reaction force of the transmission belt pinched by the primary variable pulley and the secondary variable pulley is balanced. be moved. As a result, the belt hooking diameters of these variable pulleys are increased or decreased, and the speed change states of the plurality of continuously variable transmission mechanisms are changed, and the rotational speed ratio between the primary rotating wheel and the secondary rotating shaft is adjusted steplessly. Be changed.

Here, the belt type continuously variable transmission of the present invention is provided with a primary hydraulic cylinder that applies thrust to the primary variable pulley, and a secondary hydraulic cylinder that applies thrust to the secondary variable pulley. Since the thrust forces, etc., are respectively controlled by the control means, the rotational speed ratio and the belt tension can be controlled simultaneously. Therefore, while achieving a predetermined rotational speed ratio, it is possible to adjust the belt tension of the power transmission belt to a necessary and sufficient level without causing slippage or power loss. be.

Theoretically, the larger the number of continuously variable transmission mechanisms, the larger the variable range of the rotation speed ratio while keeping the diameter of the variable pulley small. When there is a strong demand for a small and compact structure such as a transmission, it is sufficient to simply connect two continuously variable transmission mechanisms in series using one intermediate shaft. In that case, it is further desirable that the primary rotation shaft and the secondary rotation shaft be arranged on the same axis.

In addition, in order to efficiently widen the variable range of the rotation speed ratio, multiple continuously variable transmission mechanisms each have the same speed change state, that is, any one of the continuously variable transmission mechanisms is set to the maximum speed increase that is determined by design. state or the lowest speed change state,
It is desirable that the other continuously variable transmission mechanisms be configured to be in the maximum speed increasing speed change state or the lowest speed changing state.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

In FIG. 1, reference numeral 10 denotes a belt-type continuously variable transmission for a vehicle, and the driving force of an engine 12 is transmitted to a primary rotating wheel 16 via a clutch 14. The continuously variable transmission 10 includes two continuously variable transmission mechanisms 18 and 20 in series. The transmission belt 28 is constructed of an intermediate variable pulley 26, which is attached to the primary variable pulley 22, and a transmission belt 28 that is wound around the primary variable pulley 22 and the intermediate variable pulley 26 to transmit power. In addition, the continuously variable transmission mechanism 20
An intermediate variable pulley 30 provided on the intermediate shaft 24, a secondary variable pulley 34 provided on the secondary rotating shaft 32,
The intermediate variable pulley 30 and the secondary variable boob IJ3
4 and a power transmission belt 36 that is wrapped around the power transmission belt 4 and transmits power. The primary rotating wheel 16 and the secondary rotating shaft 32 are arranged to be rotatable about the respective axes on the same axis, and the intermediate shaft 24 is arranged about an axis parallel to the rotating axes 16 and 32. It is arranged so that it can rotate. Note that the output from the secondary rotating shaft 32 is transmitted to the drive wheels of the vehicle via a power transmission mechanism (not shown).

The primary variable pulley 22 and the secondary variable pulley 34 are
Fixed rotating bodies 38 and 40 fixed to the primary rotating shaft 16 and the secondary rotating shaft 32, respectively, and the primary rotating shaft 1
6 and the secondary rotating shaft 32, respectively, so as to be non-rotatably but movable in the axial direction, and to form a groove with the fixed rotating bodies 38 and 40. A primary hydraulic cylinder 46 and a secondary hydraulic cylinder 48 apply thrust to the movable rotating bodies 42 and 44 to pinch the transmission belts 28 and 36 between the fixed rotating bodies 38 and 40, respectively. By changing the magnitude of the thrust and moving the movable rotating bodies 42 and 44 toward and away from the fixed rotating bodies 38 and 40, the belt-covering diameters of the transmission belts 28 and 36 are changed. Note that the pressure receiving area of the primary hydraulic cylinder 46 is the same as that of the secondary hydraulic cylinder 4.
It is larger than the pressure receiving area of 8.

Further, the intermediate variable pulleys 26 and 30 are fixed rotating bodies 50 and 52 fixed to the intermediate shaft 24 in a state of facing each other, and fixed rotating bodies 50 and 52 provided between the fixed rotating bodies 50 and 52. 50 and 52, and movable rotating bodies 54 and 56 forming grooves between them. Movable rotating body 5
4 and 56 are provided at both ends of a slide member 58 that is disposed on the intermediate shaft 24 so as to be non-rotatable but movable in the axial direction, and are configured to be interlocked with a single weight.
As a result, the belt hooking diameters of the intermediate variable pulleys 26 and 30 are increased and decreased contrary to each other.

Here, the belt reaction force of the transmission belt 28 which is pinched by the primary variable pulley 22 is applied to the movable rotating body 54, while the movable rotating body 56 is pinched by the secondary variable pulley 34. Since the belt reaction force of the transmission belt 36 is applied, the slide member 58 is moved to a position where the belt reaction forces are balanced, but the movement stroke of the slide member 58 is the same as that of the primary variable pulley 22. Even when the belt hooking diameter of the secondary variable pulley 34 reaches a design maximum or minimum, the slide member 58 is set so as not to reach its end of movement. In other words, the primary variable pulley 22. Even when the belt hooking diameter of the secondary variable pulley 34 is the maximum or minimum, the transmission belts 28 and 36 are connected to the fixed rotating bodies 50 and 52 based on the belt reaction force of the other transmission belt 36 or 28, respectively. It is designed to be compressed by the

In addition, since the belt hooking diameters of the intermediate variable pulleys 26 and 30 are increased and decreased contradictoryly, the continuously variable transmission mechanism 18
Rotational speed ratio e+ (rotational speed NM of intermediate shaft 24 /
The rotation speed N+w of the primary rotation shaft 16) and the rotation speed ratio ex of the continuously variable transmission mechanism 20 (rotation speed N of the secondary rotation shaft 32. IJT/rotation speed N14 of the intermediate shaft 24) are both in the same shifting direction. However, when one of the continuously variable transmission mechanisms 18 or 20 reaches the designed maximum speed increase or minimum speed change state, the other continuously variable transmission mechanism 20 or 18 also changes to the maximum speed increase or maximum speed change state. It is configured to be in a deceleration speed change state. In other words, the primary variable pulley 2
When the belt hooking diameter of the secondary variable pulley 22 becomes the maximum, the belt hooking diameter of the secondary variable pulley 34 becomes the minimum, and when the belt hooking diameter of the primary variable pulley 22 becomes the minimum, the belt hooking diameter of the secondary variable pulley 34 becomes the minimum. The diameter is set to be maximum. As a result, the rotational speed ratio et of the continuously variable transmission 10 (the rotational speed N of the secondary rotating shaft 32.IJT
/Rotational speed of primary side rotating wheel 16 NIN" el '
The variable range of e1) is expressed as the product of the variable ranges of each of the continuously variable transmission mechanisms 18 and 20, and is the maximum variable range obtained when the continuously variable transmission mechanisms 18 and 20 are connected in series. becomes.

On the other hand, the hydraulic oil pumped up from the oil tank 62 by the pump 60 is regulated to line oil pressure by the pressure control valve 64, and is supplied to the secondary side hydraulic cylinder 48, and is also supplied to the primary side via the directional flow rate control valve 66. hydraulic cylinder 4
6. The pressure control valve 64 and the directional flow rate control valve 66 constitute a control means together with a control mechanism that controls their operation.
8.36 so that the necessary thrust is applied to the secondary variable pulley 34 to provide the necessary and sufficient belt tension without causing slippage or power loss.
Adjust the line oil pressure taking into consideration transmission torque, etc. Also,
The directional flow rate control valve 66 supplies line hydraulic pressure to the primary side hydraulic cylinder 46 during an increasing speed change to increase the rotational speed ratio eA, and supplies line oil pressure within the primary side hydraulic cylinder 46 during a deceleration change to reduce the rotation speed ratio eA. Hydraulic oil to oil tank 6
2, the thrust applied to the primary variable pulley 22 by the primary hydraulic cylinder 46 is controlled so that the optimum rotational speed ratio e can be obtained depending on the operating condition of the vehicle, and the flow rate of the hydraulic oil is controlled. Adjust the rotation speed ratio e? control the rate of change. Since the pressure receiving area of the primary hydraulic cylinder 46 is larger than the pressure receiving area of the secondary hydraulic cylinder 48, the continuously variable transmission 10 has a large rotational speed ratio eT by supplying the line hydraulic pressure to the primary hydraulic cylinder 46. The speed is changed to the speed increasing side.

And the belt type continuously variable transmission configured as above
At O, the movable rotating body 54 of the intermediate variable pulley 26
The belt reaction force of the transmission belt 28 acting on the transmission belt 28 is determined by the thrust applied to the primary variable pulley 22 by the primary hydraulic cylinder 46 and the rotational speed ratio e1 of the continuously variable transmission mechanism 18 at that time.
On the other hand, the belt reaction force of the transmission belt 36 acting on the movable rotating body 56 of the intermediate variable pulley 30 is determined by:
The secondary side variable pulley 34 is controlled by the secondary side hydraulic cylinder 48.
The thrust force applied to and the rotational speed ratio e of the continuously variable transmission mechanism 20 at that time. By moving the slide member 58 to a position where these reaction forces are equal and stopping it, a predetermined rotational speed ratio ea is obtained. Therefore, depending on the driving condition of the vehicle, both sleeve pressure cylinders 46
．． By controlling each of the 48 oil pressures, the optimum rotational speed ratio eT for that operating state is achieved.

Furthermore, when the hydraulic pressure of the primary hydraulic cylinder 46 is lowered by the directional flow rate control valve 66, the primary variable pulley 22
The thrust force of the transmission belt 28 decreases, and the belt reaction force of the transmission belt 28 decreases, and the slide member 58 is moved to the left in FIG. Therefore, the rotational speed ratio el+82 of the continuously variable transmission mechanism 18 and 20 are both decreased, and the rotational speed ratio e7 of the continuously variable transmission 10, which is represented by the product thereof, is also decreased. FIG. 2 is a diagram showing the lowest speed reduction state where the rotational speed ratio e7 is the smallest, and at this time, the continuously variable transmission mechanism 18
．． 20 are both in the lowest speed change state.

On the other hand, when the hydraulic pressure of the primary side hydraulic cylinder 46 is increased by the directional flow rate control valve 66, the primary side variable pulley 22
As the thrust force increases, the belt reaction force of the transmission belt 28 increases, and the slide member 58 is moved to the right in FIG. Therefore, the rotational speed ratios eInet of the continuously variable transmission mechanisms 18 and 20 are both increased, and the rotational speed ratio eT of the continuously variable transmission 10, which is represented by their product, also increases. FIG. 3 is a diagram showing the maximum speed increase state where the rotational speed ratio eT is the largest, and at this time, the continuously variable transmission mechanism 18
．． 20 are both in the maximum speed increasing state.

Here, since the belt type continuously variable transmission 10 of this embodiment is equipped with two continuously variable transmission mechanisms 18 and 20 in series, one Compared to a belt-type continuously variable transmission consisting of a step change mechanism, the rotation speed ratio e? is maintained while keeping the variable pulley diameter small. The variable range of is greatly expanded.

The belt-type continuously variable transmission 10 is also provided with a pair of hydraulic cylinders 46 and 48, and the hydraulic pressure supplied to these cylinders is controlled by a pressure control valve 64 and a directional flow rate control valve 66, respectively. Because of this, Reikai 60-1
Compared to the continuously variable transmission which changes the rotational speed ratio by driving a movable rotating body of an intermediate variable pulley as described in Japanese Patent No. 84758, the rotational speed ratio e? Not only can the belt tension of the transmission belt 28.36 be changed steplessly, but also the belt tension of the transmission belt 28.36 can be controlled to a necessary and sufficient magnitude, and while preventing the transmission belt 28.36 from slipping, it can also prevent excessive belt tension. Power loss due to tension is reduced.

Further, in this embodiment, the primary rotation shaft 16 and the secondary rotation shaft 32 are arranged on the same axis, and one intermediate shaft 24
Since the belt-type continuously variable transmission 10 is small and compact, it is extremely convenient to be mounted on a vehicle.

Furthermore, since the two continuously variable transmission mechanisms 18 and 20 are configured to be in the same speed change state, the rotational speed ratio e
There is an advantage that the variable range of 7 is efficiently expanded.

Next, another embodiment of the present invention will be described. In the following embodiments, parts common to those in the above embodiments are designated by the same reference numerals, and explanations thereof will be omitted.

The belt type continuously variable transmission 68 shown in FIG.
The intermediate variable pulleys 70 and 72 differ only in the configuration of the intermediate variable pulleys 70 and 72, and the fixed rotary bodies 76 and 78 fixedly attached to both ends of the intermediate shaft 74 cannot rotate relative to the axis of the intermediate shaft 74. Movable rotating bodies 82 and 8 are fixed to both ends of a shaft 80 that is inserted through the shaft 80 so as to be movable in the axial direction, and form grooves between them and the fixed rotating bodies 76 and 78.
It is composed of 4. Such a belt type continuously variable transmission 6
8, the movable rotating bodies 82 and 84 are moved integrally, so that the belt type continuously variable transmission 10
Exactly the same effect can be obtained.

Although the embodiments of the present invention have been described above in detail based on the drawings, the present invention can also be implemented in other embodiments.

For example, the belt-type continuously variable transmission 10°68 of the above embodiments has two continuously variable transmission mechanisms 18 and 20 connected in series, but three or more continuously variable transmission mechanisms are connected in series. It is also possible. In addition, the specifications of the continuously variable transmission mechanism 18.20, namely the belt included angle and the center distance 1 rotation speed ratio '3
The variable range etc. of ++e12 do not necessarily have to be the same.

Further, in the above embodiment, the belt type continuously variable transmission 10 for a vehicle
．． 68, the present invention can be similarly applied to other belt-type continuously variable transmissions used in machine tools and the like.

Further, in the above embodiment, the hydraulic pressure of the hydraulic cylinders 46 and 48 is controlled by the pressure control valve 64 and the directional flow rate control valve 66.
It is also possible to employ a hydraulic circuit, a hydraulic control method, etc. using a four-way flow control valve as described in Japanese Patent Application No. 58, Japanese Patent Application No. 61-37571, and the like.

Further, in the above embodiment, the pressure receiving area of the primary side hydraulic cylinder 46 is made larger than the pressure receiving area of the secondary side hydraulic cylinder 48, but depending on the hydraulic circuit, a hydraulic cylinder having an equivalent pressure receiving area may be used.

Although other examples are not given, the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit thereof.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a belt type continuously variable transmission which is an embodiment of the present invention. FIG. 2 is a diagram showing the maximum deceleration speed change state of the belt type continuously variable transmission shown in FIG. FIG. 3 is a diagram showing the maximum speed increasing speed change state of the belt type continuously variable transmission shown in FIG. FIG. 4 is a block diagram illustrating another embodiment of the present invention. 10.68: Belt type continuously variable transmission 16 2 Primary side rotating shaft 18.20: Continuously variable transmission mechanism 22 2 Primary side variable pulley 24.14: Intermediate shaft 26.3
0, 70, 72: Intermediate variable pulley 28. 36: Transmission belt 32: Secondary rotation shaft 46 2 Primary hydraulic cylinder 48: Secondary hydraulic cylinder

Claims (3)

[Claims] (1) A primary variable pulley provided on the primary rotating shaft,
A secondary variable pulley provided on the secondary rotating shaft and a movable rotary body are connected and interlocked with each other so that the belt hanging diameter is increased or decreased in opposition to each other, one pair each on one or more intermediate shafts. power transmission between the primary rotating shaft and the secondary rotating shaft, comprising an intermediate variable pulley provided and a plurality of transmission belts that are wound between the variable pulleys to transmit power; A plurality of continuously variable transmission mechanisms are constituted by a pair of variable pulleys connected in series so that the A belt-type continuously variable transmission that steplessly changes the rotational speed ratio of the primary rotating shaft and the secondary rotating shaft by changing the speed change state of a step-change transmission mechanism, wherein the primary variable pulley is a primary side hydraulic cylinder that applies a thrust to pinch the transmission belt to the secondary variable pulley; a secondary hydraulic cylinder that applies a thrust to the secondary variable pulley to squeeze the transmission belt; a control means for changing the speed change state of the continuously variable transmission mechanism by respectively controlling the magnitude of the thrust by the hydraulic cylinder cylinder and the secondary side hydraulic cylinder, and the movable rotary body of the intermediate variable pulley is configured to so that the belt reaction force of the transmission belt pinched by the primary variable pulley and the belt reaction force of the transmission belt pinched by the secondary variable pulley are balanced;
A belt-type continuously variable transmission characterized in that the intermediate shaft can be freely moved in the axial direction. (2) The primary rotation shaft and the secondary rotation shaft are arranged on the same axis, and two intermediate shafts are provided between the two intermediate shafts arranged parallel to the axis. Claim 1, which is connected by two continuously variable transmission mechanisms.
The belt-type continuously variable transmission described in . (3) The belt-type continuously variable transmission according to claim 1 or 2, wherein each of the plurality of continuously variable transmission mechanisms is configured to change to the same speed change state.