JP2007303618A - Belt type continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a belt type continuously variable transmission capable of suppressing energy loss without increasing its cost. <P>SOLUTION: The belt type continuously variable transmission comprises a first actuator for reversibly converting rotating motion into axial motion and thrusting a first movable pulley to the side of a first fixed pulley, a second actuator for reversibly converting rotating motion into axial motion and thrusting a second movable pulley to the side of a second fixed pulley, a motor for supplying the rotating motion to the first actuator, and a synchronizing means for transmitting the rotating motion of the first actuator to the second actuator so that the first actuator and second actuator are synchronized with each other to produce mutually opposite axial motion. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention has a primary pulley, a secondary pulley, and a belt that is stretched between the two pulleys, and changes the groove width of each pulley so that rotation input to the primary pulley can be transmitted via the belt to the secondary pulley. The present invention relates to a belt-type continuously variable transmission that can change a gear ratio steplessly when it is transmitted to a pulley.

Conventionally, a system described in Patent Document 1 is known as a belt-type continuously variable transmission. In this method, a constant pressing force is applied to the secondary pulley by a spring to pinch the belt, while the primary pulley is applied with a pressing force while controlling the axial position by a motor. The ratio has changed.
Japanese Patent Laid-Open No. 7-19804.

However, the belt type continuously variable transmission according to the method described in Patent Document 1 has the following problems.
1) When changing the groove width of the primary pulley and the secondary pulley and performing shift control, if the pressure is pressed with an excessive force rather than the optimum belt clamping force according to the input torque, the load acting on the belt becomes excessive, and the belt Durability decreases.
2) It is necessary to control within a range that does not exceed the holding force that can be applied by the spring, and the input torque is limited, so that it is difficult to apply to other than small vehicles.
3) When the speed ratio is controlled by the motor, it is necessary for the motor itself to generate a torque exceeding the belt clamping force, and even if a reduction gear or the like is interposed, an increase in the size of the motor cannot be avoided.

On the other hand, as a system different from Patent Document 1, there is also known a system in which a cylinder chamber is provided in each pulley and shift control is performed by hydraulic control. However, this system also has the following problems.
4) Since the groove width is changed at the time of shifting, it is necessary to change the volume together with the hydraulic pressure of each cylinder chamber, and the oil pump load is very large.
5) Even when traveling at a constant gear ratio, it is necessary to pinch the belt with a high hydraulic pressure to enable torque transmission, so the oil pump load is always large and the energy loss is large.
6) Since the gear ratio is determined by the ratio of the pinching force between the primary pulley and the secondary pulley, to achieve a certain gear ratio, the pinching force must always be managed by feedback control or the like, and the groove width of the pulley Accordingly, it is necessary to provide a mechanical feedback mechanism for controlling the hydraulic pressure supplied to the cylinder chamber, an expensive hydraulic sensor, a linear solenoid, and the like, resulting in an increase in cost.
7) When performing hydraulic control, it is necessary to provide a control valve unit. However, the manufacturing accuracy required for the control valve unit is extremely high, and it is necessary to set multiple valves, resulting in an increase in size and cost. Invite.

  The present invention has been made paying attention to the above problems, and an object of the present invention is to provide a belt type continuously variable transmission capable of suppressing energy loss without causing an increase in cost.

  In order to achieve the above object, in the belt type continuously variable transmission of the present invention, the first fixed pulley provided integrally with the input shaft, and the first fixed pulley by sliding in the axial direction on the input shaft. A primary pulley having a first movable pulley that changes a groove width between the first pulley, a second fixed pulley provided integrally with the output shaft, and the second fixed pulley by sliding in the axial direction on the output shaft. A secondary pulley having a second movable pulley that changes a groove width between the pulley, a belt stretched between the primary pulley and the secondary pulley, and reversibly converting rotational motion into axial motion. A first actuator that presses the first movable pulley toward the first fixed pulley, and a second actuator that reversibly converts rotational motion into axial motion and presses the second movable pulley toward the second fixed pulley. And the above Synchronous transmission of the rotational motion of the first actuator to the second actuator so that the motor that supplies the rotational motion to the actuator and the first actuator and the second actuator are synchronized and have opposite axial motions. Means.

  That is, when the motor rotates, the first movable pulley is moved in the axial direction by the first actuator. At this time, the rotational movement of the first actuator is transmitted to the second actuator by the synchronization means, and the second movable pulley moves in the axial direction opposite to the first movable pulley by the second actuator. The belt type continuously variable transmission determines the speed ratio based on the relationship between the groove widths of the primary pulley and the secondary pulley. At this time, since the circumferential length of the belt is constant, when the groove width of one pulley is reduced, it is necessary to increase the groove width of the other pulley. Therefore, by changing the groove width of the other pulley in synchronization with the change of the groove width of one pulley by the synchronization means, the groove width of the two pulleys can be controlled simultaneously by one motor.

  In addition, both the first actuator and the second actuator are reversibly converted (meaning that rotational motion can be converted into axial motion and that axial motion can be converted into rotational motion). A force acting in the axial direction (a reaction force opposite to the holding force) is also converted into a rotational motion. At this time, since the first actuator and the second actuator move in opposite axial directions, the rotary motion converted from the force acting on each actuator in the synchronizing means acts in the direction of canceling each other. Therefore, the motor only needs to take charge of the sliding resistance of the movable pulley at the time of shifting, and the gear ratio can be controlled with a small motor driving force.

  Hereinafter, the best mode for realizing the belt type continuously variable transmission of the present invention will be described based on an embodiment shown in the drawings.

  1 is a partial cross-sectional view and a schematic side view illustrating a configuration of a belt-type continuously variable transmission according to a first embodiment. The transmission housing HH is provided with a first partition H1 provided substantially perpendicular to the input shaft Input, and provided in an axially separated manner from the first partition H1 and provided substantially perpendicular to the output shaft Output. The second partition wall H2 has a cylindrical outer peripheral wall H3 that covers each rotating element from the outer periphery.

  The first partition wall H1 is formed with an input shaft support hole H10 in which a ball spline is formed on the inner periphery, and a primary counter shaft support hole H11 that rotatably supports a counter shaft 44 described later.

  The second partition wall H2 includes an output shaft support hole H20 having a ball spline formed on the inner periphery, and a secondary counter shaft support hole H21 that rotatably supports the counter shaft 44.

  Inside the outer peripheral wall H3 and on the engine side of the first partition wall H1, a motor support portion HM for fixing and supporting a gear ratio control motor 4 described later is provided.

  The input shaft Input transmits the driving force output from the engine (not shown) to the belt type continuously variable transmission via the torque converter, the forward / reverse switching mechanism or the like. The driving force of the output shaft Output obtained by appropriately shifting the driving force of the input shaft Input by the belt type continuously variable transmission is transmitted to the driving wheels via a differential or the like not shown.

[Configuration of belt type continuously variable transmission]
The primary pulley 1 changes the groove width between the first fixed pulley 1a provided integrally with the input shaft Input and the first fixed pulley 1a by sliding in the axial direction on the input shaft Input. And a movable pulley 1b. The secondary pulley 2 changes the groove width between the second fixed pulley 2a provided integrally with the output shaft Output and the second fixed pulley 2a by sliding in the axial direction on the output shaft Output. And a movable pulley 2b. A belt 3 is stretched between the primary pulley 1 and the secondary pulley 2, and the driving force of the input shaft Input is transmitted to the output shaft Output. The belt 3 of the first embodiment uses a compression frame feed type in which an endless band and a plurality of elements are combined. However, other types such as a chain belt, a rubber belt, and a composite belt may be used and are not particularly limited. .

[Configuration of first actuator and second actuator]
The first actuator 6 includes a second cylindrical portion 6a that forms a ball screw mechanism between a first cylindrical portion 6b having an axial spline formed on the outer periphery and an input shaft support hole H10 formed in the transmission housing HH. And a pressing portion 6c formed on the end surface of the second cylindrical portion 6a, a spline of the first cylindrical portion 6b and an inner periphery of the first cylindrical portion 6b so as to be movable in the axial direction, and a rotational motion input to the first cylindrical portion 6b. 1 external gear 42. The ball screw mechanism of the first actuator 6 is configured to reversibly convert rotational motion into axial motion.

  A thrust bearing SB1 is provided between the first external gear 42 and the first partition wall H1. A thrust bearing SB2 is provided between the pressing portion 6c and the first movable pulley 1b.

  The second actuator 7 includes a second cylindrical portion 7a constituting a ball screw mechanism between a first cylindrical portion 7b having an axial spline formed on the outer periphery and an output shaft support hole H20 formed in the transmission housing HH. And a pressing portion 7c formed on the end surface of the second cylindrical portion 7a, a spline of the first cylindrical portion 7b and an inner periphery of the first cylindrical portion 7b so as to be movable in the axial direction, and a rotational motion input to the first cylindrical portion 7b 2 external gear 46. The ball screw mechanism of the second actuator 7 is configured to reversibly convert rotational motion into axial motion.

  A thrust bearing SB3 is provided between the second external gear 46 and the second partition wall H2. Further, a pressure source 5 described later is provided between the pressing portion 7c and the second movable pulley 2b, and a thrust bearing SB4 is provided between the pressure source 5 and the second movable pulley 2b. .

  The first external gear 42 is configured to mesh with the motor external gear 41 attached to the motor drive shaft of the gear ratio control motor 4 and the first counter gear 43 attached to the counter shaft 44. Has been. The second external gear 46 is configured to mesh with a second counter gear 45 attached to the counter shaft 44.

  When a rotational motion is input in the counterclockwise direction in the screw lead direction of the ball screw mechanism formed between the second cylindrical portion 6a and the input shaft support hole H10, for example, in the schematic diagram shown in FIG. Assuming that the first movable pulley 1b is pushed out toward the first fixed pulley 1a, the screw lead direction of the ball screw mechanism formed between the second cylindrical portion 7b and the output shaft support hole H20 is the second movable pulley 2b. Is configured to move away from the second fixed pulley 2a (corresponding to the synchronizing means described in the claims).

[Configuration of pressure source]
FIG. 2 is a schematic diagram showing the configuration of the pressure source 5. The pressure source 5 includes a diaphragm 51 that can expand and contract in the axial direction and an initial set load changing unit 8. FIG. 2A shows a state in which the diaphragm 51 is expanded, and FIG. 2B shows a state in which the diaphragm 51 is contracted. The diaphragm 51 is composed of only one diaphragm.

  In the diaphragm 51, a pressure corresponding to a clamping force capable of transmitting torque by the secondary pulley 2 is enclosed. The diaphragm 51 is connected to a hydraulic pressure supply pipe 88 that supplies pressure from the initial set load changing unit 8 into the diaphragm 51.

  The initial set load changing unit 8 includes a load changing motor 81 and a load changing cylindrical portion 84.

  An external gear 82 is attached to the drive shaft of the load changing motor 81. The external gear 82 meshes with a load changing gear 83 having external teeth and having a worm 83a formed on the inner periphery.

  An initial set load changing member 87 is provided inside the load changing gear 83. The initial set load changing member 87 includes a shaft portion 87a in which a worm wheel capable of stroke in the axial direction is formed by meshing with the worm 83a on the outer periphery, and a retaining plate 87b that holds a spring 85 described later. . The worm gear is an irreversible type, and can be stroked only by the driving force from the load changing motor 81 side, and the axial force acting on the initial set load changing member 87 rotates to the load changing gear 83 and the like. Will not be transmitted as.

  The load changing cylindrical portion 84 includes a cylindrical portion 84h, a first lid portion 84f that closes the spring housing portion 84b side of the cylindrical portion 84h, a second lid portion 84g that closes the cylinder chamber 84c side of the cylindrical portion 84h, It comprises a partition wall 84e that defines a spring housing portion 84b and a cylinder chamber 84c.

  The first lid portion 84f is formed with a through hole 84fa through which the initial set load changing member 87 slides. A retaining plate 87b, a spring 85 capable of generating a pressure corresponding to a clamping force, and a retaining plate 86a connected to the piston 86 are accommodated in the spring accommodating portion 84b.

  The partition wall 84e is formed with a through hole 84d through which the shaft portion 86b of the piston 86 slides. The cylinder chamber 84c accommodates a piston surface 86c that generates oil and oil via a shaft portion 86b connected to the retaining plate 86a.

[Operation of pressure source]
Here, the operation of the pressure source 5 will be described. A certain pressure acts on the diaphragm 51. At this time, when the diaphragm 51 is pressed with a force equal to or greater than this pressure, the diaphragm 51 contracts in the axial direction, so the volume decreases, and the contracted oil is recirculated into the cylinder chamber 84c. Then, the piston 86 of the cylinder chamber 84c starts a stroke on the right side in FIG. 2 against the force of the spring 85.

  Although the spring 85 contracts, a pressure fluctuation corresponding to the displacement is generated (the pressure increases in the contraction direction), but the diaphragm 51 can be allowed to contract while maintaining a predetermined pressure or more.

  Here, since the initial set load of the spring 85 is determined by the length of the spring in the initial state, it can be changed by controlling the initial position of the retaining plate 87b. Therefore, when it is desired to change the initial set load, the load changing motor 81 is rotationally driven and the load changing gear 83 is rotated, whereby the initial set load changing member 87 is stroked in the axial direction. Thereby, since the initial set load of the spring 85 can be changed, it is possible to set from which state the pressure acting on the diaphragm 51 allows the diaphragm 51 to contract. The influence of the change in the initial set load on the shift control of the belt type continuously variable transmission will be described later in the operation of the belt type continuously variable transmission.

[Operation of belt type continuously variable transmission]
The operation of the belt type continuously variable transmission will be described with reference to FIG.

(Gear ratio steady state)
First, when the gear ratio is in a steady state, the groove widths of the primary pulley 1 and the secondary pulley 2 are constant. Since pressure corresponding to a clamping force capable of transmitting torque is sealed in the pressure source 5, this pressure presses the second movable pulley 2b. This pressing force generates a force to narrow the groove width of the secondary pulley 2 and tries to spread the belt 3 to the outer diameter side.

  If the belt 3 is to be widened to the outer diameter side in the secondary pulley 2, when the groove width of the primary pulley 1 is determined, the belt 3 tries to enter the inner diameter side of the primary pulley 1 and the first movable pulley 1b is moved. In order to spread, a pinching force is generated between the pulleys 1 and 2 and the belt 3 based on the relationship between these actions and reactions.

  When driving force is input from the input shaft Input while the pulleys 1 and 2 press the belt 3, each element is compressed by the frictional force of the primary pulley 1 and the belt 3 and the frictional force of the secondary pulley 2 and the belt 3. As the force acts, the driving force is transmitted from the primary pulley 1 to the secondary pulley 2 due to the tension difference between the endless bands, and the output shaft Output is driven.

  At this time, due to the reaction from the first movable pulley 1b, the first actuator 6 exerts a force that is pushed back to the engine side in FIG. Then, since the ball screw mechanism is configured to reversibly convert the rotational motion into the axial motion, the rotational motion, that is, torque is generated in the first actuator 6 by the input of the axial motion to the pressing portion 6c. This torque acts on the first external gear 42 via the spline of the second cylindrical portion 6 a and is transmitted to the first counter gear 43.

  On the other hand, the second actuator 6 is subjected to a force pushed back in a direction away from the engine side in FIG. Then, since the ball screw mechanism is configured to reversibly convert the rotational motion into the axial motion, the rotational motion, that is, torque is generated in the second actuator 7 by the input of the axial motion to the pressing portion 7c. This torque acts on the second external gear 46 via the spline of the second cylindrical portion 7 a and is transmitted to the second counter gear 45.

  FIG. 1B is a schematic diagram showing the rotational relationship between the motor external gear 41, the first external gear 42, the first counter gear 43 and the second counter gear 45, and the second external gear 46. is there.

  When a rotational motion is input in the counterclockwise direction in the screw lead direction of the ball screw mechanism formed between the second cylindrical portion 6a and the input shaft support hole H10, for example, in the schematic diagram shown in FIG. Assuming that the first movable pulley 1b is pushed out toward the first fixed pulley 1a, the screw lead direction of the ball screw mechanism formed between the second cylindrical portion 7b and the output shaft support hole H20 is the second movable pulley 2b. Is configured to move away from the second fixed pulley 2a.

  Therefore, the torque acting on the first external gear 42 cancels out with the torque acting on the second external gear 46 via the first counter gear 43 and the second counter gear 45, so that the gear ratio is maintained. The steady state of the gear ratio can be maintained without the need for energy.

(Shift state)
Next, in a state where the gear ratio is changed from a certain gear ratio, a rotational motion is input from the gear ratio control motor 4 to the first external gear 42. Then, the first external gear 42 rotates and rotates the first actuator 6. The first actuator 6 strokes in the axial direction by this rotational movement. At this time, since the first counter gear 43 also rotates in synchronization, the second counter gear 45 also rotates, and the second actuator 7 also rotates through the second external gear 46. Due to this rotational movement, the second actuator 7 strokes in the axial direction opposite to the direction in which the first actuator 6 strokes.

  That is, since the circumferential length of the belt 3 is constant, when the groove width of one pulley is reduced, it is necessary to increase the groove width of the other pulley. Therefore, by transmitting the rotation of the first external gear 42 to the second external gear 46 via the first counter gear 43 and the second counter gear 45, the other is synchronized with the change of the groove width of one pulley. The groove width of the pulley can also be changed. In other words, the groove widths of the two pulleys 1 and 2 can be simultaneously controlled by one gear ratio control motor 4.

  As described above, both the first actuator 6 and the second actuator 7 are reversibly converted (meaning that the rotational motion can be converted into the axial motion and the axial motion can be converted into the rotational motion). Therefore, the force acting in the axial direction of each of the movable pulleys 1b and 2b (reaction force that opposes the holding force) is also converted into rotational motion.

  At this time, since the first actuator 6 and the second actuator 7 have opposite axial movements, the rotational movements converted from the forces acting on the actuators 6 and 7 act in directions that cancel each other. . Therefore, the gear ratio control motor 4 only needs to be in charge of the sliding resistance of the first movable pulley 1b and the second movable pulley 2b at the time of shifting, thereby controlling the gear ratio with a small motor driving force. it can.

  In addition, a motor rotation speed detection sensor or the like that detects the rotation speed of the gear ratio control motor 4 is provided, and the gear ratio control motor 4 is controlled based on the sensor detection value, whereby the pulley groove width based on the motor rotation speed is controlled. That is, it becomes possible to detect the gear ratio, and there is no need to provide a mechanical feedback mechanism or the like that is applied to a hydraulically controlled belt-type continuously variable transmission, thereby reducing costs.

(Operation of pressure source in shifting state)
Here, the operation of the pressure source 5 in the shift state will be described. FIG. 3 is a diagram illustrating the relationship between the groove width of the primary pulley 1 and the groove width of the secondary pulley 2. The belt-type continuously variable transmission changes the gear ratio by controlling the groove width of the primary pulley 1 and the secondary pulley 2. At this time, since the circumferential length of the belt 3 is constant, the change rate of the groove width of the primary pulley 1 and the change rate of the groove width of the secondary pulley 2 have a slightly non-linear relationship from a geometrical relationship. Therefore, when shifting, the second actuator 7 strokes due to the same amount of rotational movement as the first actuator 6 rotationally moves, and the geometrical relationship is not satisfied.

  Therefore, the stroke in the axial direction is absorbed by the diaphragm 51 provided in the pressure source 5. Thereby, it is possible to shift with a certain steady pressure applied.

(Change of initial set load)
Next, the change of the initial set load will be described. In the belt-type continuously variable transmission, the necessary belt clamping force differs depending on the running state, that is, the input torque state, from the viewpoint of extreme belt slip prevention. This is because slippage between the pulleys 1 and 2 and the belt 3 may damage the pulley surface and cause abnormal noise, or may decrease the durability of the belt 3 itself.

  At this time, if the belt is held by a constant belt clamping force, the pressure source 5 must have a clamping force corresponding to the maximum input torque in order to cope with any running state. However, excessive frictional force accompanying the pinching force between the pulleys 1 and 2 and the belt 3 may cause a decrease in durability of the belt 3 and a decrease in torque transmission efficiency.

  Therefore, the initial set load was changed according to the running state. For example, in a traveling state where the input torque is small, the force generated by the spring 85 can be reduced by setting a lower initial set load (that is, the state where the initial set load changing member 87 is located on the right side in FIG. 2). can do. Therefore, the holding force when the second movable pulley 2b starts the stroke can be reduced.

  On the other hand, in a traveling state where the input torque is large, the force generated by the spring 85 is increased by setting a higher initial set load (that is, the state where the initial set load changing member 87 is located on the left side in FIG. 2). can do. Therefore, the holding force when the second movable pulley 2b starts the stroke can be increased.

  Thus, by controlling the belt clamping force optimally according to the running state, it is possible to minimize unnecessary belt friction and improve the durability and torque transmission efficiency of the belt. .

  As described above, in the belt type continuously variable transmission according to the first embodiment, the following effects can be obtained.

  (1) In the belt type continuously variable transmission of the first embodiment, the first fixed pulley 1a provided integrally with the input shaft Input, and the first fixed pulley 1a by sliding in the axial direction on the input shaft Input A primary pulley 1 having a first movable pulley 1b for changing the groove width between the first shaft, a second fixed pulley 2a provided integrally with the output shaft Output, and sliding on the output shaft Output in the axial direction. A secondary pulley 2 having a second movable pulley 2b for changing the groove width between the second fixed pulley 2a, a belt 3 stretched between the primary pulley 1 and the secondary pulley 2, and a rotational motion. Is reversibly converted to axial motion, the first actuator 6 pressing the first movable pulley 1b toward the first fixed pulley 1a, and the rotational motion is reversibly converted to axial motion, and the second movable pulley 2b is second fixed. Second actuator to press toward pulley 2a The first actuator 6 so that the motor 7, the gear ratio control motor 4 for supplying rotational motion to the first actuator 6, and the first actuator 6 and the second actuator 7 are synchronously moved in the opposite axial direction. Counter gears 43, 45 and the like (synchronizing means) for transmitting the rotational motion of 6 to the second actuator 7.

  That is, when the gear ratio control motor 4 rotates, the first movable pulley 1 b is moved in the axial direction by the first actuator 6. At this time, the rotational movement of the first actuator 6 is transmitted to the second actuator 7 by the synchronizing means, and the second actuator 7 moves the second movable pulley 2b in the axial direction opposite to the first movable pulley 1b. The belt type continuously variable transmission determines the speed ratio based on the relationship between the groove widths of the primary pulley 1 and the secondary pulley 2. At this time, since the circumferential length of the belt 3 is constant, when the groove width of one pulley is narrowed, it is necessary to widen the groove width of the other pulley. Therefore, by changing the groove width of the other pulley in synchronization with the change of the groove width of one pulley by the synchronizing means, the groove width of the two pulleys can be controlled simultaneously by one gear ratio control motor 4. it can.

  Further, both the first actuator 6 and the second actuator 7 are reversibly converted (meaning that the rotational motion can be converted into an axial motion and that the axial motion can be converted into a rotational motion). The force acting in the axial direction of the pulleys 1b and 2b (reaction force opposite to the holding force) is also converted into rotational motion. At this time, since the first actuator 6 and the second actuator 7 have opposite axial movements, the rotational movement converted from the force acting on each actuator in the synchronizing means acts in the direction of canceling each other. Become. Therefore, the gear ratio control motor 4 only needs to take charge of the sliding resistance of the movable pulleys 1b and 2b at the time of shifting, and thereby the gear ratio can be controlled with a small motor driving force.

  (2) A pressure source 5 is provided which is interposed between the second actuator 7 and the second movable pulley 2b and can be displaced in the axial direction while applying a belt clamping force necessary for torque transmission.

  Therefore, it is not necessary to generate a belt clamping force by an oil pump or a motor driving force, and energy loss can be suppressed. Further, since the pressure source 5 can be displaced in the axial direction, it is assumed that the change rate of the groove width of the primary pulley 1 and the change rate of the groove width of the secondary pulley 2 have a slightly non-linear relationship from the geometrical relationship. In addition, the diaphragm 51 provided in the pressure source 5 can absorb the stroke in the axial direction, and the speed can be changed with a certain steady pressure applied.

  In the first embodiment, the pressure source 5 is interposed between the second actuator 7 and the second movable pulley 2b. However, the pressure source 5 is interposed only between the first actuator 6 and the first movable pulley 1b. Alternatively, it may be provided both between the first actuator 6 and the first movable pulley 1b and between the second actuator 7 and the second movable pulley 2b. However, since the holding force of the pressure source 5 is transmitted to the other pulley via the belt 3 by providing it on one of the pulleys, it goes without saying that only one of them is sufficient.

  (3) An initial set load changing portion 8 (pressure adjusting means) for adjusting the pressure of the pressure source 5 is provided. Therefore, by controlling the belt holding force optimally according to the running state, unnecessary belt friction can be minimized, and the durability and torque transmission efficiency of the belt can be improved. In the first embodiment, the pressure of the pressure source 5 is supplied by hydraulic pressure, but the pressure may be applied by a gas type or the like.

  (4) The initial set load changing unit 8 includes a piston 86, a cylinder chamber 84c, a spring 85 that is an elastic body that presses the piston 86, and an initial set load changing member 87 that can change the initial set load of the spring 85. It was decided to have Therefore, the initial set load can be easily changed only by controlling the contraction amount of the spring 85. In the first embodiment, the spring 85 is used as the elastic body. However, another elastic body such as rubber or resin may be used.

  (5) The initial set load changing unit 8 is configured to convert the load changing motor 81, the initial set load changing member 87 that moves the initial position of the spring 85 in the stroke direction of the piston 86, and the rotational movement of the load changing motor 81. And an irreversible gear mechanism that converts the changing member 87 in the moving direction. Therefore, in a steady state after the initial set load is changed by the load changing motor 81, the force acting in the piston stroke direction is not converted into rotational motion by the irreversible gear mechanism. Therefore, energy for maintaining a steady state is not required, and energy loss can be suppressed.

  (6) The first and second actuators 6 and 7 are disposed between the first cylindrical portions 6b and 7b having axial splines formed on the outer periphery and the first and second partition walls H1 and H2 of the transmission housing HH. Second cylindrical portions 6a and 7a constituting a ball screw mechanism, pressing portions 6c and 7c formed on end surfaces of the second cylindrical portions 6a and 7a, and first and first that are fitted with splines and rotational motion is input. The first and second counter gears 43, which mesh with the first and second external gears 42, 46 of the first and second actuators 6, 7, respectively. 45. Therefore, each actuator and the synchronization means can be achieved with a simple configuration.

1 is a schematic diagram illustrating a configuration of a belt-type continuously variable transmission according to a first embodiment. 2 is a schematic diagram illustrating a configuration of a pressure source according to Embodiment 1. FIG. It is a figure showing the relationship between the stroke amount of the primary pulley of a belt type continuously variable transmission, and the stroke amount of a secondary pulley.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Primary pulley 1a 1st fixed pulley 1b 1st movable pulley 2 Secondary pulley 2a 2nd fixed pulley 2b 2nd movable pulley 3 Belt 4 Gear ratio control motor 5 Pressure source 6 1st actuator 6a, 7a 1st cylindrical part 6b, 7b Second cylindrical portion 6c, 7c Pressing portion 7 Second actuator 8 Initial set load changing portion 41 Motor external gear 42 First external gear 43 First counter gear 44 Counter shaft 45 Second counter gear 46 Second external teeth Gear 51 Diaphragm 81 Load changing motor 83 Load changing gear 83a Worm 84 Load changing cylindrical portion 84b Spring housing portion 84c Cylinder chamber 85 Spring 86 Piston 86a Retaining plate 86b Shaft portion 86c Piston surface 87 Initial set load changing member 87a Shaft portion 87b Retaining plate 88 hydraulic Supply pipe
Input Input axis
Output Output axis

Claims (6)

A primary pulley comprising: a first fixed pulley provided integrally with the input shaft; and a first movable pulley that changes a groove width between the first fixed pulley and the first fixed pulley by sliding in the axial direction on the input shaft. When,
A secondary pulley comprising: a second fixed pulley provided integrally with the output shaft; and a second movable pulley that changes a groove width between the second fixed pulley and the second fixed pulley by sliding in the axial direction on the output shaft. When,
A belt stretched between the primary pulley and the secondary pulley;
A first actuator that reversibly converts rotational motion into axial motion and presses the first movable pulley toward the first fixed pulley;
A second actuator that reversibly converts rotational motion into axial motion and presses the second movable pulley toward the second fixed pulley;
A motor for supplying rotational motion to the first actuator;
Synchronization means for transmitting the rotational motion of the first actuator to the second actuator so that the first actuator and the second actuator are synchronized in opposite axial motion;
A belt type continuously variable transmission. The belt-type continuously variable transmission according to claim 1,
It is interposed between the first actuator and the first movable pulley and / or between the second actuator and the second movable pulley, and in the axial direction while applying a belt clamping force necessary for torque transmission. A belt type continuously variable transmission comprising a displaceable pressure source. The belt type continuously variable transmission according to claim 2,
A belt type continuously variable transmission comprising pressure adjusting means for adjusting the pressure of the pressure source. In the belt type continuously variable transmission according to claim 3,
The pressure adjusting means includes a piston, a cylinder chamber, an elastic body that presses the piston, and an initial set load changing member that can change an initial set load of the elastic body. Step transmission. The belt type continuously variable transmission according to claim 4,
The initial set load change unit includes a load change motor, an initial set load change member that moves an initial position of the elastic body in the piston stroke direction, and a rotational movement of the load change motor that moves the initial set load change member. A belt type continuously variable transmission comprising: an irreversible gear mechanism for converting the direction. The belt type continuously variable transmission according to any one of claims 1 to 5,
The first and second actuators include a first cylindrical portion having an axial spline formed on the outer periphery, a second cylindrical portion constituting a ball screw mechanism between the transmission housing, and an end surface of the second cylindrical portion. Each having a pressing portion formed on the external gear, and an external gear that is fitted to the spline and receives rotational motion,
The belt-type continuously variable transmission, wherein the synchronization means is a counter gear that meshes with each of the external gears of the first and second actuators.

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