JP2010180892A - Controller of vehicular belt type continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent variation of speed change ratio during stop of a vehicle from influencing shock during the next start. <P>SOLUTION: The controller of a vehicular belt type continuously variable transmission includes a primary pulley 11, a secondary pulley 12, a V-belt 13 wound around the primary pulley 11 and the secondary pulley 12, a starting clutch 3b for transmitting rotation of an engine 1 to the primary pulley 11 in a fastened state, and a CVT control unit 20 and a hydraulic control unit 30 for controlling primary pressure Ppri and secondary pressure Psec. When the vehicle is stopped and the starting clutch 3b is in a released state, the hydraulic balance of the primary pressure Ppri and the secondary pressure Psec is set to a hydraulic balance achieving a target pulley ratio at start of the vehicle while maintaining pulley ratio during stop of the vehicle, and when starting the vehicle, fastening of the starting clutch 3b is performed while maintaining the hydraulic balance. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device for a belt type continuously variable transmission for a vehicle.

In vehicles equipped with belt-type continuously variable transmissions, when the vehicle decelerates before it stops, the gear ratio (pulley ratio) may be returned to the lowest position to prepare for the next start after stopping. Has been done.
In recent years, for the purpose of suppressing the clutch engagement shock at the next start after a stop, there is a pulley ratio that is a target pulley ratio that is returned to the high speed side from the lowest position during deceleration (for example, Patent Document 1). ).

JP 7-310795 A

However, in the belt-type continuously variable transmission according to the conventional example disclosed in Patent Document 1, for example, when the deceleration of the vehicle is very large, the vehicle stops before reaching the target pulley ratio. The pulley ratio may be fixed at a pulley ratio different from the target pulley ratio.
The pulley ratio when this vehicle is stopped varies greatly due to the deceleration of the vehicle, and it is difficult to always keep the same level of clutch engagement shock and driving force at the next start after stopping. Sometimes felt uncomfortable.

  Accordingly, an object of the present invention is to prevent variations in pulley ratio at the time of stopping from affecting a shock or the like at the next start after stopping.

  The present invention is wound around an input-side primary pulley whose groove width changes according to oil pressure, an output-side secondary pulley whose groove width changes according to oil pressure, and a primary pulley and a secondary pulley. It is installed between the engine and the primary pulley, which changes the pulley ratio by changing to the pulley contact radius according to the groove width during rotation, and transmits the rotation from the engine to the primary pulley when it is in the engaged state In the control device for a belt-type continuously variable transmission for a vehicle, the hydraulic control means includes a target at the time of start of the vehicle, and a hydraulic control means for controlling the hydraulic pressure acting on the primary pulley and the secondary pulley. The pulley ratio is determined, and when the vehicle is stopped and the frictional engagement element is in the released state, the pulley ratio when the vehicle is stopped is maintained. The hydraulic pressure acting on the primary pulley and the hydraulic pressure acting on the secondary pulley are used as a hydraulic balance that achieves the target pulley ratio, and when the vehicle starts, the friction fastening element is fastened while maintaining the hydraulic pressure balance. .

According to the present invention, the hydraulic pressure acting on the primary pulley and the hydraulic pressure acting on the secondary pulley are realized at the target pulley ratio before the frictional engagement element is fastened and the rotational driving force of the engine is input to the primary pulley. By maintaining the hydraulic balance, when the pulley ratio is mechanically changed by the torsional torque and rotation input to the primary pulley when the engagement of the frictional engagement element at the start of the vehicle is started, the vehicle stops It quickly converges from the pulley ratio to the target pulley ratio.
Therefore, even if there is a variation in the pulley ratio (transmission ratio) when the vehicle is stopped, the pulley ratio at the next start after the stop can be set to a constant value. It is possible to stabilize the driving force and prevent the driver from feeling uncomfortable. That is, the variation in the pulley ratio at the time of stopping does not affect the shock at the next start after stopping.
Further, since the pulley ratio is mechanically changed regardless of the degree of progress of the fastening of the frictional engagement element, a sensor (turbine rotational speed sensor) for measuring the degree of progress of the fastening of the frictional engagement element The number of parts can be reduced.

It is a schematic block diagram of the belt type continuously variable transmission for vehicles concerning embodiment. It is a block diagram explaining the detailed structure of a CVT control unit and a hydraulic control unit. It is a flowchart explaining the hydraulic control concerning this invention. It is a time chart explaining hydraulic control concerning the present invention.

Embodiments of a belt-type continuously variable transmission according to the present invention will be described below.
The belt-type continuously variable transmission 10 includes a primary pulley 11, a secondary pulley 12, a V belt 13, a CVT control unit 20, and a hydraulic control unit 30.

  The primary pulley 11 is disposed coaxially with the engine 1, and a torque converter 2 and a forward / reverse switching mechanism 3 are provided between the engine 1 and the primary pulley 11 in order from the engine 1 side.

  The torque converter 2 includes a pump impeller 2a coupled to the output shaft of the engine 1, a turbine runner 2b coupled to the input shaft of the forward / reverse switching mechanism 3, a stator 2c, and a lockup clutch 2d.

The forward / reverse switching mechanism 3 includes a double pinion planetary gear set 3 a as a main component, and its sun gear is coupled to the turbine runner 2 b of the torque converter 2 and the carrier is coupled to the primary pulley 11.
The forward / reverse switching mechanism 3 further includes a starting clutch 3b that directly connects the sun gear of the double pinion planetary gear set 3a and the carrier, and a reverse brake 3c that fixes the ring gear. When the start clutch 3b is engaged, the input rotation via the torque converter 2 from the engine 1 is transmitted to the primary pulley 11 as it is, and when the reverse brake 3c is engaged, the input rotation via the torque converter 2 from the engine 1 is reversed. Is transmitted to the primary pulley 11.

The primary pulley 11 is an input shaft side pulley that inputs the rotation of the engine 1 to the belt type continuously variable transmission 10. The primary pulley 11 forms a V-shaped pulley groove that is disposed opposite to the fixed conical plate 11b that rotates integrally with the input shaft 11d, and acts on the primary pulley cylinder chamber 11c. And a movable conical plate 11a that can be displaced in the axial direction by hydraulic pressure (primary pressure Ppri).
The primary pulley 11 receives the rotational driving force of the engine 1 via the forward / reverse switching mechanism 3 and the torque converter 2.
The rotation speed of the primary pulley 11 is detected by a primary pulley rotation speed sensor 26.

  The secondary pulley 12 forms a V-shaped pulley groove so as to be opposed to the fixed conical plate 12b that rotates integrally with the output shaft 12d and the fixed conical plate 12b, and acts on the secondary pulley cylinder chamber 12c. And a movable conical plate 12a that can be displaced in the axial direction by hydraulic pressure (secondary pressure Psec).

The secondary pulley 12 is connected to the differential 4 via an idler gear 14 and an idler shaft, and outputs the rotation transmitted by the V belt 13 to the differential 4.
The rotational speed of the secondary pulley 12 is detected by the secondary pulley rotational speed sensor 27.

  The V belt 13 is wound around the primary pulley 11 and the secondary pulley 12, and transmits the rotation of the primary pulley 11 to the secondary pulley 12.

The CVT control unit 20 determines the target pulley ratio, the contact friction force of the V-belt 13, etc., and sends a command to the hydraulic control unit 30 to control the belt type continuously variable transmission 10. Here, the pulley ratio is a value obtained by dividing the effective radius of the secondary pulley 12 by the effective radius of the primary pulley 11, and is synonymous with the transmission ratio.
Further, the CVT control unit 20 transmits a command to the hydraulic control unit 30 to engage and disengage the friction engagement elements (starting clutch 3b, reverse braking 3c) of the forward / reverse switching mechanism 3 and the lock-up clutch 2d of the torque converter 2. Control release etc.

  The hydraulic control unit 30 is based on a command from the CVT control unit 20, and hydraulic pressure (primary pressure Ppri) acting on the primary pulley cylinder chamber 11 c of the primary pulley 11 and hydraulic pressure acting on the secondary pulley cylinder chamber 12 c of the secondary pulley 12. (Secondary pressure Psec) is controlled.

In the belt-type continuously variable transmission 10, the rotation input to the primary pulley 11 is transmitted to the secondary pulley 12 via the V-belt 13, and is movable when the primary pulley 11 and the secondary pulley 12 are rotating. The conical plate 11a and the movable conical plate 12a reciprocate in the rotation axis direction according to the primary pressure and the secondary pressure.
When the movable conical plate 11a and the movable conical plate 12a move, the pulley groove width changes, and the V belt 13 moves in the radial direction on the primary pulley 11 and the secondary pulley 12. Therefore, the primary pulley 11 and the secondary pulley of the V belt 13 are moved. The contact radius with respect to the pulley 12 changes continuously, and the pulley ratio and the contact friction force of the V-belt 13 are controlled to values determined according to the primary pressure and the secondary pressure.

  Further, the hydraulic control unit 30 controls the hydraulic pressure (Pc) supplied to the forward / reverse switching mechanism 3 based on a command from the CVT control unit 20 to engage the frictional engagement elements (start clutch 3b, reverse brake 3c).・ Release.

  FIG. 2 is a conceptual diagram of the CVT control unit 20 and the hydraulic control unit 30 of the belt type continuously variable transmission according to the embodiment.

  As shown in FIG. 2, the CVT control unit 20 includes an engine control unit 21, an inhibitor switch 22, an accelerator operation amount sensor 23, an oil temperature sensor 24, a brake switch 25, a primary pulley rotation speed sensor 26, and a secondary pulley rotation speed sensor. 27, signals from the step motor position sensor 28 and the hydraulic sensors 29a and 29b are input.

  The engine control unit 21 outputs input torque information (torque information) input from the engine 1 to the belt type continuously variable transmission 10 to the CVT control unit 20.

The inhibitor switch 22 outputs a range signal indicating whether the selection range of a select lever (not shown) is, for example, a P (parking) range, an R (reverse) range, an N (neutral) range, or a D (travel) range. Output to the control unit 20.
Here, when the selection range of the select lever is located in the D range or the R range, the belt type continuously variable transmission 10 is in a traveling state.

  The accelerator operation amount sensor 23 outputs a signal (accelerator opening) indicating an operation amount of an accelerator pedal (not shown) to the CVT control unit 20.

  The oil temperature sensor 24 outputs a signal (Temp) indicating the temperature of the lubricating oil to the CVT control unit 20.

  The brake switch 25 outputs to the CVT control unit 20 a signal (ON / OFF signal) indicating whether an unillustrated brake is in an on state or an off state.

The primary pulley rotation speed sensor 26 outputs a signal (Npri) indicating the rotation speed of the primary pulley 11 to the CVT control unit 20.
The secondary pulley rotation speed sensor 27 outputs a signal (Nsec) indicating the rotation speed of the secondary pulley 12 to the CVT control unit 20.
The CVT control unit 20 calculates an actual pulley ratio (speed ratio) based on a signal (Npri) indicating the rotation speed of the primary pulley 11 and a signal (Nsec) indicating the rotation speed of the secondary pulley 12. At the same time, the speed (vehicle speed) of the vehicle is specified by a signal (Nsec) indicating the rotational speed of the secondary pulley 12.

  The step motor position sensor 28 outputs a signal (position signal) indicating the position of the step motor 40 for displacing a shift control valve 32 (see FIG. 2) described later to the CVT control unit 20.

The hydraulic pressure sensor 29 a outputs a signal indicating the hydraulic pressure (primary pressure Ppri) acting on the primary pulley cylinder chamber 11 c to the CVT control unit 20.
The hydraulic pressure sensor 29 b outputs a signal indicating the hydraulic pressure (secondary pressure Psec) acting on the secondary pulley cylinder chamber 12 c to the CVT control unit 20.

  The transmission control unit 20a of the CVT control unit 20 determines the target pulley ratio (transmission ratio) according to the vehicle speed, the accelerator opening, the range signal, and the primary pulley rotational speed Npri, and drives the step motor 40 to drive the actual pulley ratio. Is controlled toward the target pulley ratio.

  The pulley ratio of the primary pulley 11 and the secondary pulley 12 is controlled by a step motor 40 driven in accordance with a shift command signal from the CVT control unit 20 (shift control unit 20a), and the servo link 50 that responds to the step motor 40 is controlled. The spool 32a of the speed change control valve 32 is driven according to the displacement, the line pressure PL supplied to the speed change control valve 32 is adjusted, the primary pressure is supplied to the primary pulley 11, the groove width is variably controlled, and the predetermined pulley Set to a ratio.

The pulley pressure control unit 20b of the CVT control unit 20 determines the target value of the line pressure from the torque information, the pulley ratio (speed ratio) based on the rotation speed Npri of the primary pulley and the rotation speed Nsec of the secondary pulley, the oil temperature Temp, and the like. The line pressure is controlled by driving the solenoid 35 of the pressure regulating valve 31.
Further, the pulley pressure control unit 20b determines a target value of the secondary pressure, drives the solenoid 36 of the pressure reducing valve 33 according to the detection value of the hydraulic pressure sensor 29b and the target value, and performs feedback control (closed loop control). To control the secondary pressure.

The hydraulic control unit 30 includes a pressure regulating valve 31, a shift control valve 32, and a pressure reducing valve 33.
The pressure regulating valve 31 has a solenoid 35, and the pressure of oil pumped from the hydraulic pump 34 driven by the engine is determined according to the operation state according to a command (for example, a duty signal) from the CVT control unit 20. The pressure is adjusted to a predetermined line pressure PL.
The line pressure PL regulated by the pressure regulating valve 31 is supplied to the transmission control valve 32 and the pressure reducing valve 33, respectively.

The shift control valve 32 is a control valve that controls the hydraulic pressure (primary pressure) supplied to the primary pulley cylinder chamber 11c.
The shift control valve 32 is connected to a servo link 50 constituting a mechanical feedback mechanism, is driven by a step motor 40 connected to one end of the servo link 50, and is connected to the other end of the servo link 50. The groove width, that is, the actual pulley ratio feedback is received from the movable conical plate 11a.
The speed change control valve 32 absorbs and discharges hydraulic pressure to and from the primary pulley cylinder chamber 11c by the displacement of the spool 32a and adjusts the primary pressure so that the target pulley ratio commanded at the drive position of the step motor 40 is achieved. When the shift is completed, the spool 32a is held in the closed position in response to the displacement from the servo link 50.

The pressure reducing valve 33 is a control valve that controls the hydraulic pressure (secondary pressure) supplied to the secondary pulley cylinder chamber 12c.
The pressure reducing valve 33 has a solenoid 36 and adjusts the secondary pressure in accordance with a command (for example, a duty signal) from the CVT control unit 20.

  In the CVT control unit 20 of the belt type continuously variable transmission according to the embodiment, the select lever is put in the running range (D range, R range), and the belt type continuously variable transmission 10 remains in the running state. When the vehicle stops, N idle control (neutral control) is executed. When the vehicle restarts during execution of the N idle control, N idle drop control is performed.

  The N idle control is a control that is performed when the vehicle stops while the select lever is in the travel range (D range, R range).

For example, when the vehicle is stopped while the select lever is in the travel range (D range), the torque converter 2 (see FIG. 1) is in a stall state where the rotational speed (turbine rotational speed) Nt of the turbine runner 2b is zero. As a result, the load on the engine 1 increases and the fuel consumption increases.
Therefore, the CVT control unit 20 executes N idle control that lowers the hydraulic pressure (clutch hydraulic pressure) Pc supplied to the start clutch 3b of the forward / reverse switching mechanism 3 to place the start clutch 3b in the N idle state.

Here, the N idle state is a state in which the clutch plate gap of the start clutch 3b is almost zero and the clutch capacity, which is the upper limit torque that the start clutch 3b can transmit, is almost zero.
When N idle control is performed to bring the starting clutch 3b into the N idle state, the turbine runner 2b rotates without rotating the primary pulley 11, and the torque converter 2 is released from the stalled state. The load is reduced and the fuel consumption can be reduced.
The starting clutch is a frictional engagement element that exists on the power transmission system path at the time of starting. In the embodiment, the starting clutch (D range) is the starting clutch 3b, and the reverse traveling (R range) is the reverse brake 3c. .
Details of the N idle control are described in Japanese Patent Laid-Open No. 2008-75709.

N idle omission control is control performed when N idle control is complete | finished.
The CVT control unit 20 changes the pulley ratio (transmission ratio) to the lowest side in preparation for the next start after stopping when the vehicle decelerates before stopping, and the target pulley ratio on the lowest side when the vehicle stops. It is controlled to become.
However, when the vehicle deceleration is large, the vehicle stops before reaching the target pulley ratio, and the pulley ratio is fixed at a pulley ratio different from the target pulley ratio. The pulley ratio at varies with the deceleration and does not always have the same value.

Therefore, when the vehicle restarts under the situation where N idle control is being performed, if the N idle control is terminated and returned to normal control as it is, the pulley ratio at the time when the vehicle stops always has the same value. Therefore, each time the vehicle restarts, a shock of a different magnitude is generated, which gives the driver a sense of incongruity.
Therefore, even when the pulley ratio at the time when the vehicle stops does not always have the same value, the N idle dropout control is performed in order to suppress the variation in the magnitude of the fastening shock at the time of restart.

Hereinafter, the N idle loss control will be described in detail.
FIG. 3 shows a case where a select lever (not shown) is put in the travel range (D range), the belt-type continuously variable transmission 10 remains in the travel state, the vehicle stops, and N idle control is executed. FIG. 4 is a time chart for explaining N idle loss control, and FIG. 4 is a time chart for explaining N idle loss control.

  If it is determined in step 101 that the N idle control is being executed, in step 102, the CVT control unit 20 terminates the N idle control and returns to normal control (N idle control return condition). Confirm whether or not is established.

Since the N idle control is performed when the vehicle is stopped while the select lever is in the traveling range (D range), the CVT control unit 20 is, for example, the brake that was in the on state is turned off. At this point, it is determined that the N idle control return condition is satisfied.
Whether or not the brake has been turned off is specified based on an ON / OFF signal input from the brake switch 25.

If it is determined in step 102 that the N idle control return condition is satisfied, the CVT control unit 20 starts N idle loss control.
As a result, N idle release control of the hydraulic pressure supplied to the frictional engagement element (starting clutch 3b) of the forward / reverse switching mechanism 3 and the hydraulic pressure supplied to the primary pulley 11 and the secondary pulley 12 is performed in parallel.

  In the N idle release control of the hydraulic pressure supplied to the forward / reverse switching mechanism 3, the CVT control unit 20 outputs a command to the hydraulic control unit 30, and as shown in FIG. After holding the command pressure (clutch command pressure) of the operating hydraulic pressure supplied to (see FIG. 1) at the precharge pressure Pa from time t1 to time t3 when it is determined that the N idle control return condition is satisfied, The pressure is lowered to a pressure Pb lower than the precharge pressure Pa. Then, the clutch command pressure is increased from the pressure Pb with a predetermined gradient, and a piston (not shown) that engages / releases the start clutch 3b is stroked in a direction to engage the start clutch 3b.

  On the other hand, in the N idle release control of the hydraulic pressure supplied to the primary pulley 11 and the secondary pulley 12, in step 103, the CVT control unit 20 sets the accelerator opening based on the signal input from the accelerator operation amount sensor 23. Identify.

In step 104, the CVT control unit 20 sets a target pulley ratio based on the specified accelerator opening.
Here, the target pulley ratio is set to a value on the high side (a value on the side where the speed ratio becomes smaller) than the lowest value where the pulley ratio (speed ratio) becomes the maximum. This is to suppress a shock at the next start after stopping.

In the embodiment, the target pulley ratio is corrected according to the accelerator opening, and the value of the target pulley ratio shifts to a higher value as the accelerator opening increases.
Incidentally, in the case of FIG. 4, the accelerator opening at time t1 at which the N idle loss control is started is zero, and thus the set value of the target pulley ratio is a preset initial value.

In step 105, the CVT control unit 20 compares the pulley ratio when the vehicle stops (the pulley ratio when stopped) with the target pulley ratio.
The pulley ratio when the vehicle stops is calculated by dividing the secondary pulley rotational speed Nsec immediately before stopping by the primary pulley rotational speed Npri immediately before stopping.

When the stationary pulley ratio is larger than the target pulley ratio (stopped pulley ratio> target pulley ratio), the target pulley ratio is on the high side (the pulley ratio becomes smaller) when viewed from the stationary pulley ratio. Therefore, in Step 106, the CVT control unit 20 determines that the primary pressure and the secondary pressure become pressures that achieve the target pulley ratio in order to achieve the target pulley ratio at the time of restart. 33 are driven.
That is, the hydraulic pressure balance between the primary pressure of the primary pulley 11 and the secondary pressure of the secondary pulley 12 is instructed to the high side.

  For example, in the case of FIG. 4, at time t <b> 2, the operation position of the step motor 40 is moved to a position higher than the current position to increase only the primary pressure. The hydraulic balance is set to give the pulley ratio.

Here, during execution of the N idle control, the start clutch 3b of the forward / reverse switching mechanism 3 is in the N idle state, and only the turbine runner 2b is rotating without rotating the primary pulley 11. In the belt-type continuously variable transmission 10, the primary pulley 11 and the secondary pulley 12 rotate, whereby the groove width of the primary pulley 11 and the groove width of the secondary pulley 12 are determined by the primary pressure and the secondary pressure, respectively. To change the pulley ratio.
For this reason, at the initial stage of N idle removal control in which no rotation is input to the primary pulley 11, the starting clutch 3 b of the forward / reverse switching mechanism 3 is not engaged, and no rotational torque is input to the primary pulley 11. Therefore, when the primary pressure is increased and the primary pressure and the secondary pressure are changed to a hydraulic balance that gives the target pulley ratio (time t2), the actual pulley ratio remains the pulley ratio when the vehicle stops. Does not change.

The fixed conical plate 11b reaches a position that balances with the hydraulic balance at the time (time t6) when the clutch capacity of the starting clutch 3b increases and rotational torque starts to be input to the primary pulley 11 due to the progress of the N idle release control. The fixed conical plate 12b is displaced to change the pulley groove width. As a result, the actual pulley ratio is shifted to a position that matches the hydraulic balance, and is changed to the target pulley ratio.
Therefore, at the time (time t8) when the start clutch 3b is completely engaged and the rotation of the engine 1 is input to the primary pulley 11, the target pulley ratio is achieved, and the target pulley ratio is always set regardless of the pulley ratio when the vehicle is stopped. The vehicle is restarted at the pulley ratio.

On the other hand, if the pulley ratio at the time of stopping is not larger than the target pulley ratio at Step 105 (stop pulley ratio ≦ target pulley ratio), the target pulley ratio is set to the low side (the pulley ratio is large when viewed from the stop pulley ratio). Therefore, in step 107, the CVT control unit 20 performs the step so that the primary pressure and the secondary pressure become pressures that realize the target pulley ratio in order to realize the target pulley ratio at the time of re-starting. The motor 40 and the pressure reducing valve 33 are driven.
That is, the low pressure is instructed to the hydraulic pressure balance between the primary pressure of the primary pulley 11 and the secondary pressure of the secondary pulley 12.

Also by doing so, when the clutch capacity of the starting clutch 3b is increased and the primary pulley 11 starts to rotate, the fixed conical plate 11b and the fixed conical plate 12b are displaced to the position balanced with the hydraulic balance, and the groove The width is changed, and the pulley ratio is changed to the target pulley ratio.
Therefore, when the engagement of the starting clutch 3b is completed and the rotation of the engine 1 is input to the primary pulley 11, the target pulley ratio is achieved, and the vehicle always has the same pulley ratio regardless of the pulley ratio when the vehicle is stopped. Re-started.

  Then, when it is determined in step 108 that the engagement of the starting clutch 3b has been completed, the CVT control unit 20 ends the N idle loss control.

Until it is determined that the engagement of the starting clutch 3b has been completed, the processing (step 103 to step 107) from the acquisition of the accelerator opening to the setting of the target pulley ratio and the instruction of the hydraulic pressure balance is repeatedly executed. .
Therefore, when the accelerator opening changes until time t8 when the engagement of the starting clutch is completed, the target pulley ratio is changed according to the amount of change in the accelerator opening.

For example, in the case of FIG. 4, as indicated by the solid line in the figure, the accelerator opening is increased at time t4 before the start of fastening, so the target pulley ratio value is high (the pulley ratio is small). Changed to Then, in order to realize the changed target pulley ratio, the operation position of the step motor 40 is moved to a position higher than the current position at time t5.
As a result, only the primary pressure increases in accordance with the accelerator opening, and the hydraulic pressure balance between the primary pressure and the secondary pressure is changed to a hydraulic pressure balance that realizes the changed target pulley ratio.
Therefore, when the clutch capacity of the starting clutch 3b increases and rotation torque starts to be input to the primary pulley 11 (time t6), the actual pulley ratio is changed to the target pulley ratio after the change as shown by the solid line in the figure. Changed to

As described above, the value of the target pulley ratio is changed to the higher side as the accelerator opening increases.
Therefore, as the accelerator opening at time t5 becomes larger as indicated by the dotted line in FIG. 4, the operation position of the step motor 40 is moved to the higher side and the primary pressure is shifted to the higher side. The actual pulley ratio after the time point when the rotational torque starts to be input (time t6) also shifts to the high side where the pulley ratio becomes smaller.

  Further, in the embodiment, the target pulley ratio is set slightly higher than the lowest value at which the pulley ratio (transmission ratio) becomes maximum (pulley ratio slightly smaller than the maximum pulley ratio). 4, the run-out widths h1 and h2 of the vehicle front-rear G are slightly higher (indicated by the solid line in the figure) than when the target pulley ratio is the lowest value (indicated by the dotted line in the figure). ) Is smaller. Therefore, the engagement shock when the start clutch 3b is engaged (before and after time t7) is further suppressed.

  Incidentally, if the accelerator opening does not change until time t8 when the start clutch is engaged, the target pulley ratio set at time t2 is not changed. Therefore, as shown by the one-dot chain line in FIG. The motor position and primary pressure are held at the position and value changed at time t2.

  Here, the starting clutch 3b and the reverse brake 3c in the embodiment correspond to the frictional engagement elements in the invention, and the CVT control unit 20 and the hydraulic control unit 30 in the embodiment constitute the hydraulic control means in the invention.

As described above, in the embodiment, as shown in FIG. 1, the input-side primary pulley 11 whose groove width changes according to the oil pressure, the output-side secondary pulley 12 whose groove width changes according to the oil pressure, and the primary Between the engine 1 and the primary pulley 11, which is wound around the pulley 11 and the secondary pulley 12, changes to a pulley contact radius according to the groove width by the rotation of the primary pulley 11, and changes the pulley ratio. Hydraulic control means for controlling the hydraulic pressure acting on the starting clutch 3b of the reverse switching mechanism 3 and the primary pulley 11 and the secondary pulley 12 that are provided and transmit the rotation from the engine 1 to the primary pulley 11 when in the engaged state. (CVT control unit 20 and hydraulic control unit 30) In the control apparatus for the speed machine, the hydraulic control means determines the target pulley ratio at the start of the vehicle, as shown in FIG. 4, and when the vehicle is stopped and the start clutch 3b is in the released state, While maintaining the pulley ratio at the time of stopping, the primary pressure acting on the primary pulley cylinder chamber 11c and the secondary pressure acting on the secondary pulley cylinder chamber 12c are set as a hydraulic balance that realizes the target pulley ratio, and when the vehicle starts, The start clutch 3b is fastened while maintaining the balance.
Thereby, before the starting clutch 3b is fastened and the rotational driving force of the engine 1 is input to the primary pulley 11, the primary pressure and the secondary pressure are set to a hydraulic pressure balance that realizes the target pulley ratio, so that the vehicle The pulley ratio is mechanically changed by the torsional torque and rotation input to the primary pulley 11 when the start clutch 3b is engaged when starting, and the target pulley is determined from the pulley ratio at the time when the vehicle stops. Converge quickly to the ratio.
Therefore, even if there is a variation in the pulley ratio (transmission ratio) when the vehicle is stopped, the pulley ratio at the next start after the stop can be made a constant value. The combined shock and the rotational driving force input from the engine 1 can be stabilized, and the driver can be prevented from feeling uncomfortable.
Further, since the pulley ratio is mechanically changed regardless of the degree of progress of engagement of the start clutch 3b, a sensor (turbine speed sensor) for measuring the degree of progress of engagement of the start clutch 3b. The number of parts can be reduced.
Further, the present invention can also be applied to an automatic transmission that is not equipped with a turbine rotational speed sensor.

Further, when the vehicle is stopped while the select lever is put in the travel range (D range, R range) and the belt type continuously variable transmission 10 is in the travel state, the N idle control is performed. The configuration is such that the value of the target pulley ratio is set to a value on the higher side (the side on which the pulley ratio becomes smaller) than the lowest row where the pulley ratio becomes the maximum.
When the vehicle is stopped while the belt type continuously variable transmission 10 is in the running state, N idle control is performed. When the N idle control is finished, the start clutch 3b is quickly engaged. The fastening hydraulic pressure is increased in order to ensure the startability of the vehicle. Therefore, there is a tendency that the engagement shock when the start clutch 3b is engaged is increased. When the target pulley ratio is set to a high value, the pulley ratio (transmission ratio) at the time when the start clutch 3b is engaged is reduced, so that the torque transmitted to the drive shaft is reduced accordingly, and the start clutch 3b is engaged. The shock that accompanies can be suppressed.
Further, since the engagement shock can be reduced, the engagement of the start clutch 3b can be further accelerated, so that the start performance is improved by releasing the torque down.

Moreover, the primary pulley and the secondary pressure are set to the target pulley ratio just before the start of the engagement of the starting clutch 3b at the time of restart of the vehicle, such as when the brake pedal is released and the brake is turned off. The configuration is a hydraulic balance.
Thereby, since it can shorten the time for which the primary pulley 11, the secondary pulley 12, and the V belt 13 are loaded, the durability can be improved.

Furthermore, the target pulley ratio is corrected according to the accelerator opening that changes according to the amount of depression of the accelerator pedal, and the larger the accelerator opening, the higher the target pulley ratio value (the smaller the pulley ratio value becomes). To the side to be corrected).
When the accelerator pedal is depressed to increase the accelerator opening, the rotational driving force input from the engine 1 increases according to the accelerator opening, and the engagement speed of the start clutch 3b increases, so that the engagement shock increases.
By correcting the value of the target pulley ratio to the high side according to the magnitude of the accelerator opening and making the amount of upshift variable, the accelerator opening is large and the torsion torque input to the primary pulley 11 is large. Even at times, the fastening shock can be prevented from increasing.

In the embodiment, the case where the selection range of the select lever is the D range which is the forward range has been described as an example, but the present invention can also be applied to the case where the selection range is the R range which is the backward range. It is.
In this case, when the vehicle starts, the reverse brake 3c is engaged while the primary pressure and the secondary pressure are maintained in a hydraulic balance that achieves the target pulley ratio. Also by doing in this way, the same operation effect as the case of an embodiment is produced.

  Further, in the embodiment, as a specific example of instructing the hydraulic pressure balance between the primary pressure and the secondary pressure to the high side (see FIG. 3), the case where only the primary pressure is increased is illustrated (see FIG. 4). The pulley ratio may be shifted to the high side by reducing only the pressure or by changing both the primary pressure and the secondary pressure.

  Further, in the embodiment, when the brake that was in the on state is turned off, it is determined that the N idle control return condition is satisfied. However, the accelerator pedal is depressed and the accelerator opening is set to the threshold value. N idle control by determining whether or not the vehicle starts from the output signal of the equipment involved in starting the vehicle, such as when the parking brake (not shown) is turned off, It may be determined whether the return condition is satisfied.

DESCRIPTION OF SYMBOLS 1 Engine 2 Torque converter 3 Forward / reverse switching mechanism 3b Start clutch 3c Reverse brake 4 Differential 10 Belt type continuously variable transmission 11 Primary pulley 12 Secondary pulley 13 V belt (belt)
14 idler gear 20 CVT control unit 20a transmission control unit 20b pulley pressure control unit 21 engine control unit 22 inhibitor switch 23 accelerator operation amount sensor 24 oil temperature sensor 25 brake switch 26 primary pulley rotation speed sensor 27 secondary pulley rotation speed sensor 28 step motor position Sensors 29a, 29b Hydraulic sensor 30 Hydraulic control unit 31 Pressure regulating valve 32 Shift control valve 33 Pressure reducing valve 34 Hydraulic pump 35 Solenoid 36 Solenoid 40 Step motor 50 Servo link

Claims (4)

A primary pulley on the input side whose groove width changes according to the hydraulic pressure;
A secondary pulley on the output side whose groove width changes according to the hydraulic pressure;
A belt that is wound around the primary pulley and the secondary pulley, and changes to a pulley contact radius according to the groove width when the primary pulley rotates, thereby changing a pulley ratio;
A frictional engagement element that is provided between the engine and the primary pulley, and that transmits rotation from the engine to the primary pulley when in an engaged state;
In a control device for a vehicle belt-type continuously variable transmission, comprising: a hydraulic control means for controlling a hydraulic pressure acting on the primary pulley and the secondary pulley;
The hydraulic control means determines a target pulley ratio at the time of start of the vehicle, and maintains the pulley ratio at the time of stopping while the vehicle is stopped and the friction engagement element is in a released state. The hydraulic pressure acting on the pulley and the hydraulic pressure acting on the secondary pulley are set as a hydraulic balance that achieves the target pulley ratio, and when the vehicle starts, the friction engagement element is fastened while maintaining the hydraulic pressure balance. A control device for a belt type continuously variable transmission for vehicles.   The hydraulic control means sets the target pulley ratio to a higher pulley ratio than the lowest when the vehicle belt type continuously variable transmission is in a running state and the vehicle is stopped. The control device for a belt type continuously variable transmission for a vehicle according to claim 1.   The hydraulic pressure control means is configured to provide a hydraulic pressure balance that realizes the target pulley ratio between a hydraulic pressure acting on the primary pulley and a hydraulic pressure acting on the secondary pulley immediately before the start of fastening of the frictional engagement element at the start of the vehicle. The control device for a belt type continuously variable transmission for a vehicle according to claim 2.   4. The vehicle according to claim 3, wherein the hydraulic control unit corrects the target pulley ratio according to an accelerator opening, and corrects the target pulley ratio to a higher side as the accelerator opening is larger. Control device for belt type continuously variable transmission.

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