JP2018096383A - Continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce friction in pulley rotation, in a continuously variable transmission in which a movable sheave is axially moved by using an electric motor.SOLUTION: A continuously variable transmission includes primary and secondary pulleys, a belt, and a mechanical pulley moving mechanism 30 for adjusting a change gear ratio, the pulley moving mechanism 30 has a torque cam mechanism 40 having first and second cams 42, 44 in a manner that the first cam 42 is directly connected to a movable sheave 12 and the movable sheave is axially moved when rotation phase to the first cam, of the second cam 44 is changed, a variable speed motor 70 for changing the rotation phase or keeping the same constant, and a first planetary gear mechanism 50 in which one of three rotary elements is connected to the first cam through a power transmission mechanism 60, one of the remaining elements is connected to the second cam, and the remaining one is connected to the variable speed motor. In the power transmission mechanism, a speed transmission ratio is determined to rotate both cams in the same direction at an equal speed in fixing a gear change ratio to make the relative rotation phases of the first and second cams constant in stopping the rotation of the variable speed motor, and power supply is stopped in the variable speed motor in stopping the rotation.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a continuously variable transmission in which a movable sheave is moved in an axial direction by a mechanical actuator using a torque cam mechanism.

In a belt-type continuously variable transmission, a technique has been developed in which a movable sheave of a primary pulley or a secondary pulley is axially moved by an actuator to change the groove width of the pulley.
For example, Patent Document 1 discloses a slide cam that slides in the axial direction by a cam mechanism when the rotational phase is changed and moves the movable sheave in the axial direction, and a mechanical actuator such as a motor that changes the rotational phase of the slide cam. A continuously variable transmission is disclosed.

  When the movable sheave is moved in the axial direction by the actuator, the drive member that is driven by the actuator and moves the movable sheave in the axial direction like the above slide cam is basically non-rotated except when the rotational phase is changed. On the other hand, since the movable sheave rotates at high speed, a thrust bearing that allows relative rotation and transmits axial force is interposed between the drive member and the movable sheave.

Japanese Patent Laid-Open No. 2006-1013

  However, the thrust bearing between the drive member such as a slide cam and the movable sheave rotates according to the differential rotation between the two while constantly receiving the axial load due to the belt tension. For this reason, the thrust bearing causes friction of pulley rotation, and causes an increase in power transmission loss of the continuously variable transmission. In particular, when the transmission torque by the continuously variable transmission is large, the axial load due to belt tension also increases, and the friction of pulley rotation by the thrust bearing also increases, so the increase in power transmission loss becomes more significant.

  The present invention was devised in view of such problems, and in a continuously variable transmission that moves a movable sheave in an axial direction by using a mechanical actuator, it is possible to reduce friction of pulley rotation and reduce power transmission loss. It is an object of the present invention to provide a continuously variable transmission capable of suppressing the occurrence of the above.

  (1) In order to achieve the above object, a continuously variable transmission according to the present invention includes a primary pulley and a secondary pulley, a belt spanned between the pulleys, and a movable sheave of at least one of the pulleys. And a mechanical pulley moving mechanism that adjusts a gear ratio by moving the shaft in the axial direction. The mechanical pulley moving mechanism is coaxial with the movable sheave by sliding the cam surfaces of each other. The first cam member is directly connected to the movable sheave, and the relative rotation phase of the second cam member with respect to the first cam member is provided. A torque cam mechanism that changes the entire length of the movable sheave in the axial direction, an electric transmission motor that changes or keeps the relative rotation phase of the second cam member, a sun gear, a carrier, Three rotating elements of the ring gear, and any one of these rotating elements is connected to the first cam member via a power transmission mechanism, and any one of the remaining rotating elements is the second rotating element. A first planetary gear mechanism coupled to a cam member and the remaining rotating elements coupled to the actuator, wherein the power transmission mechanism is configured to stop the first and second rotations when the transmission motor is stopped. A speed transmission ratio is set so that the first and second cam members rotate at the same speed in the same direction when the transmission gear ratio is fixed so that the relative rotation phase of the cam member is constant, and the transmission motor stops the rotation. The power supply is sometimes stopped.

  (2) Stopping the supply of power to the speed change motor when the rotation is stopped is a predetermined value in which the rotation stop holding torque necessary to stop the speed change motor is set based on the cogging torque of the speed change motor. It is preferable to carry out when the driving situation is below the value.

  (3) It is preferable to determine the driving state based on a driving torque of a driving source input to the primary pulley and a gear ratio of the continuously variable transmission.

  (4) When a clutch is provided between the drive source and the primary pulley and the clutch is not completely engaged, power supply to the transmission motor is not stopped when the rotation is stopped. It is preferable to drive the electric motor so that a torque corresponding to the rotation stop holding torque is generated.

  (5) Immediately before starting when the brake is detected when the vehicle is stopped in the shift range, the power supply to the transmission motor is not stopped when the rotation is stopped, and the electric motor is rotated. It is preferable to drive so that a torque corresponding to the stop holding torque is generated.

  According to the present invention, when the relative rotation phases of the first and second cam members are made constant by the speed change motor, the total length of the torque cam mechanism is maintained at a constant value corresponding to the relative rotation phases of the first and second cam members. Then, power is transmitted between the primary pulley and the secondary pulley at a fixed gear ratio corresponding thereto. The first cam member is directly connected to the movable sheave, no friction is generated between the first cam member and the pulley, and the first and second cam members rotate at the same speed in the same direction. Since there is no relative rotation, friction due to rotation does not occur. For this reason, generation | occurrence | production of power transmission loss is suppressed.

When the relative rotation phase of the second cam member with respect to the first cam member is changed by the speed change motor, the total length of the torque cam mechanism is changed, and power is transmitted between the primary pulley and the secondary pulley at a gear ratio corresponding thereto. The At the time of changing the relative rotation phase, the first cam member and the second cam member rotate relative to each other. However, since the speed change is short and the speed of the relative rotation is low, friction due to the relative rotation occurs. It is suppressed to a few things.
Further, when the gear ratio is fixed so that the relative rotation phase of the first and second cam members is fixed by stopping the rotation of the transmission motor, the first and second cam members rotate at the same speed in the same direction. A speed transmission ratio is set, and when the rotation is stopped, the power supply to the speed change motor is stopped, thereby promoting energy saving.

It is a typical lineblock diagram of a continuously variable transmission concerning one embodiment of the present invention. It is a typical lineblock diagram of the pulley concerning one embodiment of the present invention. It is a typical block diagram which shows the mechanical pulley moving mechanism which concerns on one Embodiment of this invention with a pulley. It is a velocity diagram (collinear diagram) of the planetary gear mechanism of the mechanical pulley moving mechanism according to an embodiment of the present invention. It is a block diagram which shows the mechanical structure of the mechanical pulley moving mechanism which concerns on one Embodiment of this invention. It is a block diagram which shows the control structure of the transmission motor in the mechanical pulley movement mechanism which concerns on one Embodiment of this invention. It is a figure which illustrates the instruction | indication characteristic of the transmission motor of the mechanical pulley moving mechanism which concerns on one Embodiment of this invention. It is a flowchart explaining control of the gear ratio by the speed-change motor in the mechanical pulley moving mechanism which concerns on one Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. Note that the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiment. Each configuration of the following embodiments can be implemented with various modifications without departing from the spirit thereof, and can be selected or combined as appropriate.

[Continuously Variable Transmission According to Embodiment]
FIG. 1 is a block diagram schematically showing a continuously variable transmission according to an embodiment. As shown in FIG. 1, a drive source 2 including an internal combustion engine (engine) for driving a vehicle, an electric motor, and the like is included. A rotary shaft 10 coupled to the fixed sheave 8 of the primary pulley 6 of the continuously variable transmission 5 is connected via a forward / reverse switching mechanism 4 constituted by a planetary gear mechanism or the like. A movable sheave 12 having a sheave surface that forms a V-shaped groove of a pulley facing the sheave surface of the fixed sheave 8 is disposed on the rotary shaft 10 so as to be slidable in the axial direction and not relatively rotatable. Yes.

  A drive wheel (not shown) is connected to the drive shaft 18 coupled to the fixed sheave 16 of the secondary pulley 14 of the continuously variable transmission 5 via a differential mechanism or the like, and the drive shaft 18 is connected to the fixed sheave 16. A movable sheave 20 having a sheave surface that forms a V-shaped groove of a pulley opposite to the sheave surface of the pulley is disposed so as to be slidable in the axial direction and not relatively rotatable.

Further, between the sheaves 16 and 20 of the secondary pulley 14, a spring 22 and a cam mechanism 24 that apply a biasing force in the direction of narrowing the V-shaped groove are interposed.
A belt 26 is wound around the pulleys 6 and 14.
Further, the spring 22 and the cam mechanism 24 function as a thrust adjustment mechanism that adjusts the thrust of the secondary pulley 14 to adjust the clamping force of the belt 26.

  FIG. 1 shows a state where the gear ratio is on the low side and the state on the high side for the primary pulley 6, the secondary pulley 14, and the belt 26. A low-side state is shown in each outer half of the primary pulley 6 and the secondary pulley 14, and a high-side state is shown in each inner half. Regarding the belt 26, the low-side state is indicated by a solid line, and the high-side state is indicated by a broken line. However, the high state indicated by the broken line only indicates the positional relationship between the pulley and the belt in the radial direction, and the actual belt position does not appear in the inner half of the pulley.

  A mechanical pulley moving mechanism 30 that moves the movable sheave 12 in the axial direction and adjusts the gear ratio is disposed on the back side (surface opposite to the sheave surface) 13 of the movable sheave 12 of the primary pulley 6. . In FIG. 1, the mechanical pulley moving mechanism 30 is described in a very simplified manner. However, the mechanical pulley moving mechanism 30 includes a torque cam mechanism 40, a planetary gear mechanism 50, a power transmission mechanism 60, and an electric motor as an actuator. And a motor 70.

[Mechanical Pulley Moving Mechanism According to Embodiment]
As shown in FIG. 2, the torque cam mechanism 40 includes a first cam (first cam member) 42 that is directly connected to the movable sheave 12 and rotates integrally therewith, and a first cam surface 42 a formed on the first cam 42. An opposing second cam surface 44a is formed at one end (left side in the figure) and the other end (right side in the figure) is connected to the back surface 13 of the movable sheave 12 via a thrust bearing 46 (second cam). Cam member) 44.

  The first cam 42 and the second cam 44 are arranged coaxially with the axis of the rotary shaft 10 on the outer peripheral side of the rotary shaft 10. The rotary shaft 10 is rotatably supported by a transmission casing (not shown) via bearings 32 and 34. The first cam 42 that rotates integrally with the movable sheave 12 is supported so as to be non-rotatable relative to the rotary shaft 10 and movable in the axial direction by the same configuration as the movable sheave 12 (spline mechanism with a ball or a roller interposed). Has been. The second cam 44 is supported so as to be relatively rotatable with respect to the rotary shaft 10 via a bearing or the like (not shown), and is held at a certain position with respect to the rotary shaft 10 in the axial direction so as not to move.

  That is, the first cam 42 is directly connected (fixedly connected) to the movable sheave 12, and the second cam 44 is supported so as not to move in the axial direction with respect to the rotary shaft 10, whereby the relative rotational phases of the two cams 42, 44 are obtained. With this displacement, the movable sheave 12 can be moved in the axial direction (change the gear ratio).

  The first cam surface 42 a and the second cam surface 44 a are formed on the end surfaces of the respective cylindrical cams 42, 44 facing each other, and the shape thereof is a spiral slope inclined with respect to the axis SC of the rotary shaft 10. Is formed. In each embodiment, the inclined surfaces (that is, the first and second cam surfaces 42a and 44a) are inclined so as to approach the back surface 13 of the movable sheave 12 along the rotational direction of the primary pulley 6 when the vehicle is traveling forward. ing.

  When the relative rotation phase between the second cam 44 and the first cam 42 is changed, the total length of the torque cam mechanism 40 is changed. Since the second cam 44 does not move in the axial direction, the first cam 42 moves in the axial direction together with the movable sheave 12. Therefore, when the relative rotation phase is changed by rotating the second cam 44 relative to the first cam 42, the movable sheave 12 moves in the axial direction, and the transmission ratio of the continuously variable transmission 5 is adjusted.

  In the following embodiments, the parallel gear mechanism 60 is illustrated as the power transmission mechanism, but the power transmission mechanism is not limited to the parallel gear mechanism, and for example, a planetary gear mechanism may be used.

  When a planetary gear mechanism is used as the power transmission mechanism, relative movement along the axial direction between the first cam 42 and the power transmission mechanism 60 is allowed and relative rotation is impossible (rotational power can be transmitted). It is preferable to interpose a slide allowance mechanism 80 (such as a spline mechanism with a ball or roller interposed). When the planetary gear mechanism 50 and the power transmission mechanism 60 are composed of helical gears, the slide allowance mechanism 80 cannot be moved in the axial direction between the gears. Necessary to allow relative movement between. However, if either one or both of the planetary gear mechanism 50 and the power transmission mechanism 60 are made of spur gears, relative movement between the spur gears becomes possible, so that the slide allowing mechanism 80 can be omitted. .

  The planetary gear mechanism 50 is disposed on the outer periphery of the second cam 44, and any one of the three rotating elements of the sun gear S, the carrier C, and the ring gear R (the first rotating element) is used as the power transmission mechanism 60. The other rotating element (second rotating element) is connected to the second cam 44, and the remaining rotating element (third rotating element) is electrically operated as an actuator. The motor 70 is connected.

  If the planetary gear mechanism 50 constrains the rotation of any one of the three rotating elements (sun gear S, carrier C, ring gear R), one of the remaining two rotating elements is the reaction element. Thus, the other rotating element rotates at a gear ratio (= output rotation speed / input rotation speed, also referred to as speed ratio) according to the gear ratio. The rotation restriction in this case is to set the rotation speed to a predetermined speed (including a constant speed and a rotation stop). The rotation is restricted by the electric motor 70. That is, by controlling and restricting the rotation of the third rotating element by the electric motor 70, the first rotating element and the second rotating element rotate at a gear ratio corresponding to the gear ratio. Therefore, the electric motor 70 is also referred to as a transmission motor.

Since the first rotation element of the planetary gear mechanism 50 is connected to the first cam 42 via the power transmission mechanism 60, the rotational speed (N _{cam 1} ) of the first cam 42 is the first rotation speed of the planetary gear mechanism 50. The rotating element rotates at a rotational speed corresponding to the speed transmission ratio (N _{cam 1} / N ₁ ) of the power transmission mechanism 60 with respect to the rotational speed (N ₁ ) of the rotating element. The power transmission mechanism 60 is connected to the first cam 42 and the first cam 42 when the actuator 70 is at a predetermined rotation restraint of the third rotation element, that is, when the third rotation element is rotated or stopped at a predetermined speed (a constant speed). The speed transmission ratio is set so that the two cams 44 rotate at a constant speed.
Assuming that the rotational speed Nin of the input element, the number of teeth Zin, the rotational speed Nout of the output element, and the number of teeth Zout, the speed transmission ratio is defined by the reciprocal of the gear ratio (speed ratio) as shown in the following equation. .
Speed transmission ratio = Nout / Nin = Zin / Zout = 1 / Gear ratio (speed ratio)

  When the rotation restraint state of the third rotating element by the speed change motor 70 is changed, that is, the rotation speed of the third rotating element is changed (if the third rotating element is in the stopped state, it is rotated, or the third rotating element is rotated by a predetermined amount). If the speed is changed from the predetermined rotational speed), the first cam 42 is directly connected to the movable pulley 12, and therefore the rotational speed does not change. Therefore, the first cam 42 and the second cam 44 A differential rotation occurs between them, and the second cam 44 rotates relative to the first cam 42 to change the relative rotation phase between the first cam 42 and the second cam 44. Thereby, the movable sheave 12 moves in the axial direction, and the gear ratio of the continuously variable transmission 5 is adjusted.

Hereinafter, specific configurations of the planetary gear mechanism 50 and the power transmission mechanism 60 of the mechanical pulley moving mechanism 30 will be described.
In the present embodiment, the first planetary gear mechanism 50, the sun gear in S _1, the carrier C _1, the planetary gear in P _1, show respectively the ring gear in R _1, each of these rotary elements, The standard (for example, the number of gear teeth and the tooth width) required in the device configuration is assumed.

[Specific configuration of planetary gear mechanism and power transmission mechanism]
As shown in FIG. 3, the planetary gear mechanism 50 of the mechanical pulley moving mechanism 30 according to the present embodiment is separated from the rotation axis of the primary pulley 6 (movable sheave 12) and is on another rotation axis parallel to the rotation axis. Is arranged.
In the planetary gear mechanism 50, the sun gear S is connected to the rotation shaft of the transmission motor 70, the ring gear R is drivingly connected to the second cam 44, and the carrier C is drivingly connected to the power transmission mechanism 60. Here, although the transmission motor 70 is directly connected to the sun gear S, the transmission motor 70 is preferably connected to the sun gear S via a reduction gear (particularly a high reduction gear having a large reduction ratio).

  The carrier C corresponds to the first rotating element and is connected to the first cam 42 via the power transmission mechanism 60. The ring gear R corresponds to the second rotating element, and an external gear (also referred to as gear R) 51a formed outside the ring gear R and an external gear (also known as gear A) formed outside the second cam 44. 51b) meshes with 51b. The sun gear S corresponds to the third rotation element and is coupled to the rotation shaft of the transmission motor 70.

  Further, the power transmission mechanism 60 is constituted by a parallel gear mechanism. This parallel gear mechanism includes an external gear (also referred to as gear B) 62a coupled to the first cam 42, an external gear (also referred to as gear C) 62b coupled to the carrier C and meshed with the external gear 62a, It is composed of

The parallel gear mechanism 60, which is a power transmission mechanism, allows the first cam 42 and the second cam 44 to move in the same direction when the speed change motor 70 fixes the gear ratio so that the relative rotational phase of the first cam 42 and the second cam 44 is constant. The speed transmission ratio is set so as to rotate at a constant speed. That is, the rotation speed of the first cam 42 (N _{cam 1),} relative to the rotational speed of the carrier C, which is the first rotating element of the planetary gear mechanism 50 (Nc3), the transmission ratio of the power transmission mechanism 60 (N _{cam 1} / Nc3).

In the parallel gear mechanism 60, if the number of teeth of the external gear 62a coupled to the first cam 42 is Z _B and the number of teeth of the external gear 62b coupled to the carrier C is Z _C , the parallel transmission mechanism is a parallel transmission mechanism. the transmission ratio by the gear mechanism 60, the rotational speed of the external gear 62a (the rotational speed of the first cam 42) _{N B} and the rotational speed ratio of _{N C} (rotational speed of the carrier C) of the external gear 62b _{(N B} / N _C ) and is determined by the number of teeth Z _B and Z _C of the gears 62a and 62b.
Speed transmission ratio = N _B / N _C = Z _C / Z _B

  Here, assuming that the transmission gear ratio is fixed when the transmission motor 70 is stopped, the alignment chart of the planetary gear mechanism 50 is as shown by a solid line L in FIG. In FIG. 4, α is the gear ratio of the planetary gear mechanism 50. As shown in FIG. 4, the ratio between the rotational speed of the ring gear R and the rotational speed of the carrier C is 1 + α.

Further, the rotational speed of the carrier C N _A and the rotational speed of the ring gear R rotation speed ratio between the N _R [external gear (gear R) 51a rotational speed of] [external gear (gear A) 51b rotational speed of] (N _A / N _ROUT ) is determined by the number of teeth Z _A and Z _R of each gear 62a and 62b, and is as follows.
N _A / N _R = Z _R / Z _A

Here, in consideration of the rotational speed ratio _(N A / N _R), the first cam 42, when the fixed gear ratio of the relative rotational phase of the second cam 44 is constant, the first cam 42, second cam 44 To set to rotate at the same speed in the same direction, the speed transmission ratio of the parallel gear mechanism 60 (ratio of the number of teeth Z _B and Z _C of each gear 62a and 62b) is set so as to satisfy the relationship of the following equation: do it.
N _B / N _C = Z _C / Z _B = (1 + α) · (N _A / N _R ) = (1 + α) · (Z _R / Z _A )
In the alignment chart of FIG. 4, Z _R / Z _A = 1 is set for easy understanding.

  By setting the speed transmission ratio of the parallel gear mechanism 60 in this way, the rotation of the speed change motor 70 is stopped and the sun gear S of the planetary gear mechanism 50 is fixed, so that the second cam 44 and the first cam 42 A constant rotation phase is maintained without relative rotation. That is, the overall length of the torque cam mechanism 40 is not changed, and the speed ratio of the continuously variable transmission 5 is kept constant.

  On the other hand, when the transmission motor 70 is operated so that the sun gear S rotates in the same direction (forward direction) as the carrier C and the ring gear R (see the arrow of the transmission a), the alignment chart of the planetary gear mechanism 50 is as follows. As indicated by a broken line La in FIG. 4, the ring gear R (that is, the second cam 44) of the planetary gear mechanism 50 is at a lower speed than before the operation of the speed change motor 70, and the second cam 44 is the first cam 42. And the relative rotation phase is changed. Thereby, the total length of the torque cam mechanism 40 is changed, and the gear ratio is changed.

  Conversely, when the transmission motor 70 is operated so that the sun gear S rotates in the opposite direction (negative direction) to the carrier C or the ring gear R (see the arrow of the transmission b), the alignment chart of the planetary gear mechanism 50 is shown in FIG. The ring gear R (that is, the second cam 44) of the planetary gear mechanism 50 becomes faster than before the operation of the speed change motor 70, and the second cam 44 is relative to the first cam 42. Rotate to change the relative rotational phase. Thereby, the total length of the torque cam mechanism 40 is changed, and the gear ratio is changed.

  Therefore, when changing the gear ratio (that is, when changing gears), the transmission motor 70 is rotated in a predetermined direction, and when fixing the gear ratio, the rotational speed of the transmission motor 70 is set to zero. Stop rotation.

  Here, the relationship between the elements for adjusting the speed ratio by the speed change motor 70 is shown in FIG. 5. When the speed change motor 70 rotates, this rotation is transmitted to the planetary gear mechanism 50. If there is a high speed reducer between the planetary gear mechanism 50 and the planetary gear mechanism 50, the rotation of the transmission motor 70 is transmitted to the high speed reducer, and is transmitted from the high speed reducer to the planetary gear mechanism 50.

  The planetary gear mechanism 50 transmits rotation to the first cam 42 at a rotation speed ratio corresponding to the planetary gear ratio α. Further, the output torque of the transmission motor 70 is changed in accordance with the rotation speed ratio and input to the first cam 42. Accordingly, a thrust (clamping force for clamping the belt) is applied to the primary pulley 6 according to the input torque through the cam mechanism 40, and the length of the cam mechanism 40 is adjusted by adjusting the input torque and adjusting the thrust. The transmission ratio of the continuously variable transmission 5 is changed. At this time, the output torque of the transmission motor 70 is feedback-controlled based on the actual transmission ratio of the continuously variable transmission 5.

  Focusing on the control at this time, as shown in FIG. 6, the transmission motor 70 includes an ATCU (automatic transmission control unit) 100 that controls the continuously variable transmission 5 and a motor CU (motor control unit) that controls the transmission motor 70. ) 110 to control the operation.

  That is, the ATCU 100 feedback-controls the transmission motor 70 so that the actual transmission ratio Rr of the continuously variable transmission 5 becomes the target transmission ratio Rt. The target speed ratio Rt is set according to the driving state of the vehicle (vehicle speed, accelerator opening (or drive source load), etc.), and the actual speed ratio Rr is the rotation of the primary pulley 6 detected by a sensor (not shown). It is calculated from the speed (actual primary pulley rotational speed) Npri and the rotational speed of the secondary pulley 14 (actual secondary pulley rotational speed) Nsec (Rr = Npri / Nsec).

  Then, the speed change motor 70 is feedback controlled so that the difference (= Rt−Rr) between the target speed ratio Rt and the actual speed ratio Rr is within an allowable range. Here, the difference (= Rt−Rr) corresponds to the deviation amount (rotational speed deviation amount) Ngap of the actual primary pulley rotational speed Npri with respect to the target primary pulley rotational speed Nprit corresponding to the target speed ratio Rt. Rt−Rr) will be described as the rotational speed deviation amount Ngap.

Note that the allowable range is defined by the intersection value a determined from the detection accuracy of the actual primary pulley rotation speed Npri and the actual secondary pulley rotation speed Nsec. As shown in FIG. In the state 1), the rotational speed of the speed change motor 70 is controlled so that the rotational speed deviation amount Ngap decreases. If the rotational speed deviation amount Ngap is in the state of the following equation (2), the speed of the speed change motor 70 is rotated. Hold the number.
| Ngap |> a (1)
| Ngap | ≦ a (2)

  The ATCU 100 outputs a rotational speed command (rotational speed command) corresponding to the rotational speed deviation amount Ngap to the motor CU110 as described above. In the motor CU110, the speed change motor 70 rotates the rotational speed corresponding to the rotational speed command (target rotational speed). ), The rotational speed of the transmission motor 70 is controlled (rotational speed control). Note that the rotation speed command of the transmission motor 70 includes the target rotation speed zero, and as shown in FIG. 7, when the rotation speed deviation amount Ngap holds the rotation speed of the transmission motor 70 in the state of equation (2). , Command the target speed zero.

  In order to realize this rotational speed control, the transmission motor 70 needs to generate a torque corresponding to a load applied to the transmission motor 70. In motor CU110, in order to control transmission motor 70 to the rotational speed corresponding to the rotational speed command from ATCU 100, the motor necessary for setting the rotational speed of transmission motor 70 to the target rotational speed (including zero rotational speed) Nmot Torque (motor required torque) Tmot is calculated, and the transmission motor 70 is controlled based on the motor required torque Tmot.

In this device, when the rotational speed deviation amount Ngap is in the state of the expression (2), the rotational speed (rotational speed) of the speed change motor 70 is held at zero, that is, in the rotation stopped state.
In particular, when the rotational speed of the speed change motor 70 is set to zero, the cogging torque when the speed change motor 70 is stopped is used to stop the power supply to the speed change motor 70 and stop the drive of the speed change motor 70. The motor 70 is held in the rotation stopped state.
That is, the transmission motor 70 is an electric motor, and the cogging torque Tcog is generated by the action of the iron core and the permanent magnet even when no current flows. This cogging torque Tcog is used as a torque for holding the electric motor 70 in the rotation stop state.

  The electric motor 70 is connected to the torque cam mechanism 40. In order to keep the electric motor 70 in the rotation stopped state, it is necessary to keep the entire length of the torque cam mechanism 40 constant. It is necessary to apply a thrust (necessary clamping force) F sufficient to clamp the belt to the movable sheave 12 to the torque cam mechanism 40, and the necessary clamping force F is applied by the electric motor 70. Therefore, in order to hold the electric motor 70 in the rotation stopped state, it is necessary to cause the electric motor 70 to generate the necessary motor torque Tmot corresponding to the necessary clamping force F.

Here, the necessary motor torque Tmot can be calculated by the following equation (A).
Tmot = F * R * tan (θ + tan ⁻¹ μ) * α * ir (A)
F: Required clamping force
R: Cam radius
θ: Cam angle
μ: Cam dynamic friction coefficient
α: Planetary gear ratio (= ratio of sun gear teeth / ring gear teeth)
ir: Child reduction ratio of high speed reducer The required clamping force (= primary pulley required thrust) F can be calculated by the following equation (B).
F = Teng * ip * b (B)
However, Teng: Engine torque (if the travel motor is a drive source, the torque of the travel motor is input from the engine CU or the travel motor CU (not shown))
ip: pulley ratio
b: Coefficient for determining the balance thrust value with the secondary pulley necessary for maintaining the pulley ratio ip

  If the cogging torque Tcog is equal to or greater than the motor required torque Tmot (Tcog ≧ Tmot), the motor required torque Tmot is not generated in the speed change motor 70, that is, the power supply to the speed change motor 70 is stopped and the drive is stopped. Even in this case, the transmission motor 70 can be held in the rotation stopped state.

  However, if the footbrake is detected to be off when the vehicle is stopped in the shift range D or R range (that is, the state immediately before starting), the engine torque Teng increases thereafter, and the required clamping force It is assumed that the motor required torque Tmot becomes equal to or greater than the cogging torque Tcog as F increases and the motor required torque Tmot increases. In this case, even if the cogging torque Tcog is equal to or greater than the motor required torque Tmot, the motor required torque Tmot for maintaining the speed change motor 70 in the rotation stopped state is generated in the speed change motor 70 and then the motor required torque Tmot. Is prepared when the cogging torque becomes Tcog or more.

  When there is a torque converter with a lock-up clutch between the power source (in this case, the engine) 2 and the continuously variable transmission 5, the fact that the lock-up clutch is engaged in the lock-up state, that is, the power Since the calculation condition for the cogging torque is that the power source 2 and the continuously variable transmission 5 are in a directly connected state, if the power source 2 and the continuously variable transmission 5 are not in a directly connected state, the motor needs the cogging torque Tcog. Even if the torque is greater than or equal to the torque Tmot, the transmission motor 70 is caused to generate the necessary motor torque Tmot for maintaining the transmission motor 70 in the rotation stopped state.

Here, the control of the transmission ratio by the transmission motor will be described with reference to the flowchart of FIG. Note that the flowchart of FIG. 8 is repeatedly performed at a predetermined control cycle.
As shown in FIG. 8, first, the ATCU 100 sets a target speed ratio Rt of the continuously variable transmission 5 according to the driving state of the vehicle (step S10). Next, it is determined whether or not the target speed ratio Rt is the same as the previous time, that is, whether or not the target speed ratio Rt is held constant (step S20).

  If the target speed ratio Rt is not the same as that of the previous time, that is, if the target speed ratio Rt is changed, the motor CU110 needs the target rotational speed Nmot of the speed change motor 70 and the motor so that the target speed ratio Rt can be achieved. The torque Tmot is calculated as described above (step S30). Then, the target rotational speed Nmot and the required motor torque Tmot are commanded to the transmission motor 70 (step S40).

  On the other hand, if the target gear ratio Rt is the same as the previous time, it is determined whether or not the direct coupling clutch condition, that is, whether the power source 2 and the continuously variable transmission 5 are directly coupled (step S50). If the direct clutch condition is not satisfied, the routine proceeds to step S30, where the motor CU110 calculates the target rotational speed Nmot and the motor required torque Tmot of the transmission motor 70, and the routine proceeds to step S40, where the transmission motor 70 receives the target rotational speed Nmot. The motor required torque Tmot is commanded.

  If the target gear ratio Rt is the same as the previous time and the direct clutch condition is satisfied, the target rotational speed Nmot of the transmission motor 70 is zero, and the required motor torque Tmot is calculated so that the rotational speed of the transmission motor 70 is zero. (Step S60). Then, the motor required torque Tmot and the motor cogging torque Tcog are compared to determine whether the cogging torque Tcog is equal to or greater than the motor required torque Tmot (Tcog ≧ Tmot) (step S70).

  Here, if the cogging torque Tcog is equal to or greater than the motor required torque Tmot, whether or not the vehicle is in a state just before starting, that is, whether or not the foot brake is detected when the vehicle is stopped in the shift range of the D range or the R range. It is determined whether or not (step S80). Here, if the state is just before starting, the process proceeds to step S30, where the motor CU110 calculates the target rotational speed and the required motor torque Tmot of the transmission motor 70, and proceeds to step S40, where the transmission motor 70 receives the target rotational speed and the motor. Command the required torque Tmot.

  On the other hand, if the cogging torque Tcog is not less than the motor required torque Tmot and is not in a state immediately before starting, the power supply to the speed change motor 70 is stopped without causing the speed change motor 70 to generate the motor required torque Tmot. Even if the driving is stopped, the transmission motor 70 can be held in the rotation stopped state. Therefore, the power supply to the transmission motor 70 is stopped and the drive is stopped (step S90).

  In the mechanical pulley moving mechanism 30 according to this embodiment, the first cam 42 is directly connected to the movable sheave 12 as described above, and friction due to rotation does not occur between the first cam 42 and the pulley 6. In addition, when the transmission gear ratio is fixed, the first cam 42 and the second cam 44 rotate at the same speed in the same direction and do not rotate relative to each other, so that friction due to rotation does not occur between these two members. For this reason, generation | occurrence | production of power transmission loss is suppressed.

  Further, when changing the speed ratio, the rotational speed of the electric motor 70 is changed to rotate the second cam 44 relative to the first cam 42 (and hence the pulley 6), so that the first cam 42 and the second cam 44 are changed. The relative rotation phase with is changed. At this time, the thrust of the belt 26 received by the second cam 44 toward the other end side (right side in the figure) via the first cam 42 is applied to the thrust bearing 46, and friction due to relative rotation occurs. Since the speed change is a short time and the speed of the relative rotation is low, friction due to the relative rotation is generated but suppressed to a small amount.

  Further, in this apparatus, when the transmission ratio is maintained, the rotation speed of the electric motor 70 is maintained at zero. At this time, power is supplied to the transmission motor 70 using the cogging torque when the transmission motor 70 is stopped. Since the speed change motor 70 is held in the rotation stopped state while stopping the drive of the speed change motor 70 and stopping the rotation, an energy saving effect is obtained.

  However, in the state immediately before the start when the foot brake is detected when the vehicle is stopped in the shift range D range or R range, the required motor torque Tmot is shifted even if the cogging torque Tcog is greater than the required motor torque Tmot. Since it is generated by the motor 70, when the required motor torque Tmot becomes equal to or greater than the cogging torque Tcog at the time of subsequent start, it can be dealt with promptly.

[Others]
In each of the above embodiments, the primary pulley 6 is equipped with a mechanical pulley moving mechanism, but the secondary pulley 14 may be equipped with a mechanical pulley moving mechanism. Further, a mechanical pulley moving mechanism can be provided on both the primary pulley 6 and the secondary pulley 14.

2 Drive source 5 Continuously variable transmission 6 Primary pulley 8 Primary sheave 6 fixed sheave 10 Primary pulley 6 rotating shaft 12 Primary pulley 6 movable sheave 14 Secondary pulley 16 Secondary pulley 14 fixed sheave 18 Secondary pulley 14 drive shaft 20 Movable sheave of secondary pulley 14 22 Spring constituting thrust adjusting mechanism 24 Cam mechanism constituting thrust adjusting mechanism 26 Belt (endless belt-like member)
DESCRIPTION OF SYMBOLS 30 Mechanical pulley moving mechanism 40 Torque cam mechanism 50 1st planetary gear mechanism 60 Power transmission mechanism 70 Electric motor (transmission motor) as an actuator
80 Slide allowance mechanism 100 ATCU (automatic transmission control unit)
110 Motor CU (Motor Control Unit)
S Sun gear C Carrier R Ring gear

Claims (5)

A primary pulley and a secondary pulley, a belt spanned between the two pulleys, and a mechanical pulley moving mechanism that adjusts a gear ratio by moving a movable sheave of at least one of the pulleys in the axial direction. In a continuously variable transmission,
The mechanical pulley moving mechanism is
The first cam member is directly connected to the movable sheave, the first cam member being directly connected to the movable sheave, the first and second cam members being arranged in series on the same axis as the movable sheave. A torque cam mechanism that changes a total length when the relative rotation phase of the cam member with respect to the first cam member is changed, and moves the movable sheave in an axial direction;
An electric speed change motor for changing or maintaining the relative rotation phase of the second cam member;
It has three rotating elements, a sun gear, a carrier, and a ring gear, and any one of these rotating elements is connected to the first cam member via a power transmission mechanism, and any one of the remaining rotating elements is A first planetary gear mechanism coupled to the second cam member and the remaining rotating elements coupled to the actuator;
In the power transmission mechanism, the first and second cam members are in the same direction when the speed ratio is fixed so that the relative rotation phase of the first and second cam members is constant when the transmission motor stops rotating. Speed transmission ratio is set to rotate at a constant speed,
The continuously variable transmission is characterized in that power supply to the transmission motor is stopped when the rotation is stopped. When the rotation is stopped, the power supply to the speed change motor is stopped because the rotation stop holding torque necessary for stopping the speed change motor is less than a predetermined value set based on the cogging torque of the speed change motor. The continuously variable transmission according to claim 1, wherein the continuously variable transmission is performed in a driving state. 3. The continuously variable transmission according to claim 2, wherein the operating condition is determined based on a driving torque of a driving source input to the primary pulley and a gear ratio of the continuously variable transmission. A clutch is provided between the drive source and the primary pulley;
When the clutch is not completely engaged, power supply to the speed change motor is not stopped when the rotation is stopped, and the electric motor is driven so that a torque corresponding to the rotation stop holding torque is generated. 4. The continuously variable transmission according to claim 2, wherein the continuously variable transmission. In the state immediately before starting when the brake is detected when the vehicle is stopped in the shift range, the power supply to the transmission motor is not stopped at the time of the rotation stop, and the electric motor is turned to the rotation stop holding torque. The continuously variable transmission according to any one of claims 2 to 4, wherein the continuously variable transmission is driven so as to generate a torque according to the frequency.

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