JP2006300115A - Engagement force controller of start friction element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engagement force controller of a start friction element capable of avoiding shock and engine stall when a clutch is engaged even in a vehicle stopped in a stall state reducing impact torque when a clutch is engaged and reducing impact torque when the clutch is engaged in a vehicle having a belt type continuously variable transmission. <P>SOLUTION: This transmission controller 41 controlling the engagement force of the forward clutch according to the operating conditions reduces the engagement force of the forward clutch 20 when the heat generation amount of the forward clutch 20 reaches a predetermined value before the forward clutch 20 is fully engaged when the vehicle is started. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a start clutch that is fastened when a vehicle starts and transmits engine power to a drive wheel.

As this type of technology, there is disclosed a technique for controlling the clutch torque to be larger than the engine torque when a predetermined clutch slip control time elapses (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 8-111002

  When the driver stops the vehicle in a stalled state on a slope, if the clutch torque is controlled to be larger than the engine torque as in the prior art, a shock or engine stop at the time of clutch engagement will occur. There is a risk that it will occur. In particular, in a vehicle equipped with a belt type continuously variable transmission, there is a risk that the impact torque at the time of clutch engagement is input to the belt and durability is reduced.

  The present invention has been made paying attention to the above-mentioned problems. The object of the present invention is to avoid the occurrence of a shock or engine stop when the clutch is engaged even when the vehicle is stalled. In a vehicle-mounted vehicle, it is an object to provide a starting friction element fastening force control device capable of reducing impact torque at the time of clutch fastening.

  In order to achieve the above object, according to the present invention, a fastening force control means for controlling a fastening force of a starting friction element that performs transmission and interruption of power from a prime mover according to a driving state, and at the time of starting a vehicle And a fastening force correcting means for reducing and correcting the fastening force of the starting friction element when the heat generation amount of the starting friction element reaches a predetermined heating value before the starting friction element is completely fastened.

  Therefore, it is possible to avoid the occurrence of a shock or engine stop when the clutch is engaged, and it is possible to reduce the impact torque when the clutch is engaged in a vehicle equipped with a belt type continuously variable transmission.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out a starting friction element fastening force control apparatus according to the present invention will be described below with reference to the drawings.

  First, the configuration of the fastening force control device for the starting friction element of this embodiment will be described.

  FIG. 1 is an overall system diagram showing a configuration of a drive system and a control system of a vehicle equipped with a belt-type continuously variable transmission including an engine controller 40 and a transmission controller 41.

  A vehicle equipped with a belt-type continuously variable transmission includes an engine 1, a forward / reverse switching mechanism 6 having a starting clutch, a belt-type continuously variable transmission 19 that continuously shifts between input and output, and an output gear 12 that decelerates the output. And a drive gear 13 and left and right drive wheels 17 and 18 driven via a differential gear 14 and left and right drive shafts 15 and 16.

  The engine 1 is connected to a clutch input shaft 5 of a forward / reverse switching mechanism 6 via an engine output shaft 2 and a damper 3.

  The forward / reverse switching mechanism 6 includes a simple planetary gear 22 capable of switching the rotation direction and the gear ratio, a forward clutch 20 that is fastened and constitutes a starting friction element of the present invention, and a forward friction that is fastened backward and is also of the present invention. And a reverse brake 21 as an element.

  The simple planetary gear 22 includes a sun gear 22s that rotates concentrically with the clutch output shaft 7 integrated with a primary pulley shaft, a plurality of pinions 22p that mesh with the sun gear 22s, a ring gear 22r that meshes with the pinion 22p, and a pinion And a carrier 22c that rotatably supports the carrier 22c.

  The sun gear 22 s is connected to the driven side portion of the forward clutch 20 and the clutch output shaft 7. The carrier 22c is connected to the fixed side portion of the reverse brake 21. The ring gear 22r is connected to the drive side portion of the forward clutch 20 respectively.

  The forward clutch 20 is configured to be switchable between an engaged state where power can be transmitted between input and output and a released state where power cannot be transmitted.

  The reverse brake 21 is configured to be switchable between a fastening state in which the carrier 22c is fixed to be non-rotatable and a release state in which the carrier 22c is rotatable.

  The belt type continuously variable transmission 19 changes the gear ratio between the input and output shafts of the belt type continuously variable transmission 19 continuously. A primary pulley 8 coupled to a primary pulley shaft integral with the clutch output shaft 7, a secondary pulley 10 coupled to a secondary pulley shaft 11, a CVT belt 9 spanned between the primary pulley 8 and the secondary pulley 10, It has.

  The primary pulley 8 and the secondary pulley 10 have fixed sheaves 8a and 10a and movable sheaves 8b and 10b that approach and leave the fixed sheaves 8a and 10a, respectively. A primary pulley oil chamber 34 is provided on the back surface of the movable sheave 8 b of the primary pulley 8, and a secondary pulley oil chamber 35 is provided on the back surface of the movable sheave 10 b of the secondary pulley 10.

  The pressure oil obtained by suction from the oil tank 30 by the oil pump 31 is supplied to the line pressure control unit 32. With this line pressure control unit 32, the pressure oil is adjusted to a predetermined line pressure and supplied to the hydraulic control unit 33 and the secondary pulley oil chamber 35. By controlling the hydraulic pressure supplied to the primary pulley oil chamber 34 by the hydraulic control unit 33, the movable sheave 8b is relatively moved so as to approach and separate from the fixed sheave 8a. With this configuration, the belt type continuously variable transmission 19 is configured to change the rotation radius of the CVT belt 9 to change speed.

  An output gear 12 is fixed to the end of the secondary pulley shaft 11 on the secondary pulley 10 side of the belt type continuously variable transmission 19, and meshed with a drive gear 13 having a larger diameter than the output gear 12.

  Two pinions of the differential gear 14 are fixed to the drive gear 13, and side gears are engaged with these pinions from the left and right, respectively. Drive gears 15 and 16 are connected to the side gears to drive the left and right drive wheels 17 and 18.

  Next, the control system of the vehicle equipped with the belt type continuously variable transmission according to the first embodiment will be described with reference to FIG.

  The control system includes an engine controller 40 that controls the engine 1, a transmission controller 41 as a fastening force control means that controls the hydraulic control unit 33 of the forward / reverse switching mechanism 6 and the belt-type continuously variable transmission 19, and these controllers. And sensors connected to each other.

  Connected to the engine controller 40 are a throttle opening sensor 42 for detecting the throttle opening TVO and an engine rotation speed sensor 43 for detecting the rotation speed of the engine output shaft 2 of the engine 1. The engine controller 40 controls the engine 1 based on the throttle opening information and the engine speed information.

  The transmission controller 41 is connected to a brake switch 44 that outputs a brake ON / OFF signal, a gradient sensor 45 that detects a road gradient, and a vehicle speed sensor 46 that detects a vehicle speed. From these, brake switch information, clutch output shaft rotational speed information, vehicle speed information information, and the like are input.

  In addition, engine control information is input to the transmission controller 41 via a CAN communication line 50 that connects the engine controller 40 and the transmission controller 41.

  The transmission controller 41 calculates the clutch torque according to the driving situation based on the engine control information and information from each sensor. The forward clutch solenoid 48 for controlling the hydraulic pressure supplied to the forward clutch 20 and the reverse brake solenoid 49 for controlling the hydraulic pressure supplied to the reverse brake 21 are controlled according to the calculated clutch pressure required for generating the clutch torque. By this control, the forward clutch 20 and the reverse brake 21 are switched to a completely engaged state in which the clutch torque is set to be equal to or higher than the engine torque, a slip state in which the clutch torque is set to be smaller than the engine torque, and a released state in which the clutch torque is zero. The transmission controller 41 corresponds to the fastening force control means of the present invention.

  The transmission controller 41 controls the hydraulic pressure supplied to the primary pulley oil chamber 34 by a solenoid valve provided in the hydraulic pressure control unit 33 based on engine control information and information from each sensor. By this control, the belt type continuously variable transmission 19 changes speed by changing the rotation radius of the CVT belt 9.

  Next, the operation will be described.

[Stall condition on uphill road]
For example, on an uphill road or the like, the driver may adjust the amount of depression of the accelerator without using a brake to stop the vehicle so that the vehicle is in a so-called stall state. In such a stall state, the forward clutch 20 is slipping and the clutch input shaft 5 rotates together with the engine 1, but the clutch output shaft 7 is input from the drive wheels 17 and 18 side. It is not rotating in proportion to the torque due to road load. When the stall state continues and the forward clutch 20 continues to slip, the forward clutch 20 is quickly worn out due to heat generation, and the durability deteriorates.

  For this reason, it is conceivable to increase the clutch torque of the forward clutch 20 to reduce the slip amount and suppress heat generation. However, when the clutch torque of the forward clutch 20 is increased, the engine torque transmitted to the drive wheels 17 and 18 also increases, so the vehicle starts against the driver's intention to stop the vehicle.

  Further, when the heat generation amount of the forward clutch 20 is large, it is necessary to quickly increase the clutch torque to stop the heat generation. However, when the load on the road surface is high, such as when the vehicle is stopped on an uphill road, if the clutch torque of the forward clutch 20 is quickly increased, a large load torque may be input to the engine 1 to cause an engine stop. There is. Further, in a vehicle equipped with a belt-type continuously variable transmission such as the present embodiment, the durability of the CVT belt 9 may deteriorate due to an input shock of engine torque by rapidly increasing the clutch torque of the forward clutch 20. .

[Clutch torque correction control]
Therefore, in this embodiment, when the heat generation amount of the forward clutch 20 becomes equal to or greater than a predetermined heat generation amount in the stall state, clutch torque correction control for correcting the clutch torque of the forward clutch 20 is performed. This clutch torque correction control corresponds to the fastening force correction means of the present invention.

  FIG. 2 is a diagram illustrating clutch torque control according to the throttle opening TVO, which is performed in the transmission controller 41. In the normal state, the forward clutch 20 of the present embodiment is subjected to clutch torque normal control for increasing the clutch torque as the throttle opening TVO increases as indicated by the one-dot chain line in FIG.

  For example, when the throttle opening TVO is TVOs and the heat generation amount of the forward clutch 20 exceeds a predetermined heat generation amount α, the throttle opening TVO is within the range where the throttle opening TVO is smaller than TVOs ′ as shown by the solid line in FIG. Regardless, clutch torque correction control for fixing the clutch torque to Tc is performed. The predetermined heat generation amount α is set sufficiently smaller than the durable heat generation amount of the forward clutch 20 and is variably set according to the ambient temperature such as the oil temperature. In the present embodiment, the throttle opening TVO changes according to the accelerator opening, and corresponds to the accelerator opening of the present invention. Of course, it may be controlled by the accelerator opening.

  The clutch torque Tc is a clutch torque at which the vehicle moves backward and becomes a predetermined vehicle speed Vc (<0), and the clutch torque Tc is set according to the magnitude of the gradient based on information from the gradient sensor 45. In a vehicle not equipped with the gradient sensor 45, the forward clutch 20 is controlled so as to supply a pre-jersey pressure, that is, an engagement pressure immediately before the forward clutch 20 enters the slip state, so that the vehicle is surely moved backward. To do. Therefore, if the throttle opening TVO is in the state of TVOs, the vehicle moves backward by the clutch torque correction control of the forward clutch 20, and the driver can be urged to perform a brake operation or accelerator depression by the backward movement of the vehicle.

  Further, the throttle opening TVOs ′ is set larger than the throttle opening TVOs at the start of clutch torque control by a predetermined opening as a hysteresis, and is set to the throttle opening TVO that allows the vehicle to sufficiently advance. Thus, even if the driver depresses the accelerator, the vehicle does not proceed if the throttle opening is smaller than the throttle opening TVOs ′ at the start of the clutch torque correction control. Therefore, even if the driver attempts to adjust to a new accelerator depression amount that can be brought into a stalled state, the stalled state cannot be made again. Further, when the driver depresses the accelerator, it is possible to prompt the driver to depress beyond the throttle opening TVOs ′ at which the vehicle can sufficiently move forward.

  FIG. 3 is a flowchart showing the flow of clutch torque correction control in the present embodiment.

  In step S1, it is determined whether or not a clutch torque correction control flag is ON. While this clutch torque correction control flag is ON, the clutch torque correction control indicated by the solid line is performed instead of the clutch torque normal control indicated by the one-dot chain line in FIG. When the clutch torque correction flag is ON, the process proceeds to step S2, and when the clutch torque correction flag is OFF, the process proceeds to step S6.

  Hereinafter, a flow for determining whether a condition for turning off the clutch torque correction control flag is satisfied when the clutch torque correction control flag is ON will be described.

  In step S2, it is determined whether or not the brake is ON. If the brake is ON, the process proceeds to step S5 to end the clutch torque correction control.

  In step S3, it is determined whether or not the throttle opening TVO is equal to or greater than TVOs ′. If the throttle opening TVO is equal to or greater than TVOs', the process proceeds to step S4. If the throttle opening TVO is smaller than TVOs', the process proceeds to step S10 with the clutch torque correction control flag ON.

  In step S4, it is determined whether or not the vehicle speed Vsp is greater than a predetermined value Vo. The predetermined value Vo is set to a value at which it can be determined that the driver is going to advance the vehicle, and is determined by experiment or calculation.

  In step S5, the clutch torque correction control flag is turned OFF because the conditions for ending the clutch torque correction control are satisfied by the determination in step S2 to step S4.

  Hereinafter, a flow for determining whether a condition for turning off the clutch torque correction control flag is satisfied when the clutch torque correction control flag is ON will be described.

  In step S6, it is determined whether or not the brake is OFF. If the brake is OFF, the process proceeds to step S7. If the brake is ON, the driver determines that the vehicle is about to be stopped by the brake, and the process proceeds to step S10 while the clutch torque correction control flag remains OFF.

  In step S7, it is determined whether or not the vehicle speed Vsp is 0 (zero). If the vehicle speed is zero, the vehicle is stalled, and the process proceeds to step S8. If the vehicle speed is generated, the process proceeds to step S10.

  In step S8, the amount of heat generated by the forward clutch 20 is measured. The amount of heat generated by the forward clutch 20 is calculated by calculation from the differential rotational speed calculated from a clutch input shaft rotational speed sensor and a clutch output shaft rotational speed sensor (not shown) and the clutch pressure of the forward clutch.

  In step S9, it is determined whether or not the heat generation amount Q of the forward clutch 20 is greater than a predetermined heat generation amount α. If the heat generation amount Q of the forward clutch 20 is larger than the predetermined heat generation amount α, the process proceeds to step S10. If the heat generation amount Q of the forward clutch 20 is equal to or less than the predetermined heat generation amount α, the heat generation amount Q of the forward clutch 20 is still sufficient even in the stalled state. The process proceeds to step S11 with OFF.

  In step S10, the clutch torque correction control flag is set to ON because the conditions for starting the clutch torque correction control are satisfied by the determinations in steps S6 to S8.

  Hereinafter, the engagement force control of the forward clutch 20 according to the clutch torque correction control flag will be described.

  In step S11, it is determined whether or not a clutch torque correction control flag is ON. When the clutch torque correction control flag is ON, the process proceeds to step S12 to perform clutch torque correction control. When the clutch torque correction control flag is OFF, the routine proceeds to step S13 and clutch torque normal control is performed.

  In step S12, the throttle opening TVO is read, and clutch torque correction control is performed according to the throttle opening TVO as shown by the solid line in FIG.

  In step S13, the throttle opening degree TVO is read, and the clutch torque normal control is performed according to the throttle opening degree TVO as shown by the one-dot chain line in FIG.

  In step S14, a clutch pressure corresponding to the clutch torque determined in step S11 or step S12 is calculated.

  In step S15, the forward clutch solenoid 48 is controlled in accordance with the clutch pressure calculated in step S14, and pressure oil is supplied to the forward clutch 20.

  FIG. 4 is a diagram illustrating clutch pressure control during clutch torque correction control. At time T1, when the clutch pressure Ps for generating the clutch torque Ts is reduced to the clutch pressure Pc for generating the clutch torque Tc, it may be gradually decreased as shown in FIG. It may be good or may be lowered stepwise as shown in FIG. When the clutch pressure is gradually reduced, the vehicle can slowly start to reverse. On the other hand, when the clutch pressure is lowered stepwise, the vehicle can be moved backward with good response, so that the driver can be surely recognized that the vehicle has moved backward and the brake operation or the depression of the accelerator can be urged.

  On the other hand, at time T2, when the clutch torque Tc is increased to the clutch torque corresponding to the throttle opening TVO, the clutch torque is gradually increased to avoid sudden engagement. As a result, a shock due to an engine stop or a sudden input of engine torque is avoided.

  FIG. 5 is a time chart of control of the forward clutch 20 performed in the transmission controller 41.

  When the stall state is detected at time t0, the heat generation amount Q of the forward clutch 20 is measured. Since the heat generation amount Q at this time is equal to or less than the predetermined heat generation amount α, the clutch torque correction control flag is OFF.

  When the heat generation amount Q of the forward clutch 20 becomes larger than the predetermined heat generation amount α at time t1, clutch torque correction control is started. When the clutch torque correction control is started, the clutch pressure is gradually decreased to Pc in order to control the clutch torque Tc. At time t2, the vehicle moves backward and the vehicle speed becomes Vc.

  At time t3, when the driver depresses the accelerator and the throttle opening TVO becomes equal to or greater than TVOs ′, the clutch pressure is gradually increased to control the clutch torque according to the throttle opening TVO as shown in FIG.

  At time t4, when the driver returns the accelerator and the throttle opening TVO becomes TVOs' or less again before reaching the predetermined vehicle speed Vo of the condition for turning off the clutch torque correction control, the clutch torque Tc is controlled to control the clutch torque Tc. The pressure is gradually reduced to Pc. At time t5, the vehicle moves backward and the vehicle speed becomes Vc.

  At time t3, when the driver depresses the accelerator and the throttle opening TVO becomes equal to or greater than TVOs ′, the clutch pressure is gradually increased to control the clutch torque according to the throttle opening TVO as shown in FIG.

  At time t7, when the predetermined vehicle speed Vo, which is a condition for turning off the clutch torque correction control, is reached, the clutch torque correction control flag is turned off, and the clutch torque normal control shown by the one-dot chain line in FIG. 2 is performed.

  When the amount of heat generated by the forward clutch 20 increases in the stalled state due to the above control, the brake operation and the depression of the accelerator are encouraged to prevent the stalled state. Can be suppressed.

  Next, the effect of the present embodiment will be described.

  (1) When the heat generation amount Q of the forward clutch 20 reaches the predetermined heat generation amount α, the clutch torque of the forward clutch 20 is reduced and corrected. Therefore, for example, in a stalled state on an uphill road, the vehicle moves backward by reducing the clutch torque of the forward clutch 20, and the driver can be prompted to stop the vehicle by a brake operation or start the vehicle by depressing the accelerator. Therefore, since the heat generation of the forward clutch 20 can be suppressed, the durability of the forward clutch 20 can be improved.

  (2) The clutch torque correction control is terminated when the throttle opening TVO after the start of the clutch torque correction control becomes equal to or larger than the throttle opening TVOs ′ set larger than the throttle opening TVOs at the start of the clutch torque control. I did it. Therefore, when the driver depresses the accelerator so as to be equal to or greater than the throttle opening TVOs ′, it is possible to ensure forward traveling of the vehicle. On the other hand, even if the driver depresses the accelerator, the vehicle does not proceed if the throttle opening is smaller than the throttle opening TVOs ′ at the start of the clutch torque correction control. Therefore, even if the driver attempts to adjust to a new accelerator depression amount that can be brought into a stalled state, the stalled state cannot be made again.

  (3) The clutch torque correction control is terminated when the brake is depressed and the brake switch is turned on. Therefore, since normal clutch torque control is performed after the brake is released, vehicle start response can be ensured.

  (4) The clutch torque correction control is terminated when the vehicle speed exceeds the predetermined vehicle speed Vo. Therefore, good clutch torque control can be performed even when the throttle opening is lowered after the vehicle starts.

  (5) When reducing the clutch torque Tc during the clutch correction control, the clutch pressure is gradually reduced. Thus, the vehicle can slowly start to reverse.

  (6) When the clutch torque Tc is decreased during the clutch correction control, the clutch pressure is decreased stepwise. Therefore, since the vehicle can be moved backward with good response, the driver can be surely recognized to move backward, and the brake operation or the depression of the accelerator can be urged.

  (7) When the clutch torque Tc is increased to the clutch torque corresponding to the throttle opening TVO, the clutch torque is gradually increased to avoid sudden engagement. Therefore, it is possible to avoid a shock caused by an engine stop or a rapid input of engine torque.

  Although the forward clutch 20 has been described above, the reverse brake 21 may be similarly controlled during reverse.

  In Example 1, the fastening force control device for the starting friction element of the present invention is not only a vehicle equipped with a belt type continuously variable transmission, but also a vehicle equipped with a stepped transmission, a vehicle equipped with a toroidal continuously variable transmission, and a vehicle equipped with an automatic MT. In other words, it can be applied to various vehicles having a friction element that is fastened at the time of starting and transmits input torque from a drive source, such as a hybrid vehicle and an electric vehicle.

1 is an overall system diagram showing a drive system and a control system of a vehicle equipped with a belt type continuously variable transmission to which a fastening frictional force control device for a starting friction element is applied. It is a figure which shows the control value of the clutch torque according to a throttle opening. It is a flowchart which shows the flow of clutch torque correction control. It is a figure which shows control of the clutch pressure during clutch torque correction control. It is a time chart of clutch torque correction control.

Explanation of symbols

20 Forward clutch 21 Reverse brake 41 Transmission controller 44 Brake switch 45 Gradient sensor 46 Vehicle speed sensor

Claims (7)

A fastening force control means for controlling the fastening force of the starting friction element that performs transmission and interruption of power from the prime mover according to the operating state,
A fastening force correcting means for reducing and correcting the fastening force of the starting friction element when the heat generation amount of the starting friction element reaches a predetermined heating amount before the starting friction element is completely fastened when starting the vehicle;
A fastening friction force control device for a starting friction element. The fastening force control device for a starting friction element according to claim 1,
The fastening force correction means ends the reduction correction when the accelerator opening after the start of the reduction correction is greater than a predetermined opening by an amount greater than the accelerator opening at the start of the reduction correction. Fastening force control device for starting friction element. The fastening force control device for a starting friction element according to claim 1 or 2,
The fastening force control device for a starting friction element, wherein the fastening force correction means ends the reduction correction when a brake is depressed. The fastening force control device for a starting friction element according to any one of claims 1 to 3,
The fastening force control device for a starting friction element, wherein the fastening force correction means ends the reduction correction when the vehicle speed becomes equal to or higher than a predetermined speed. The fastening force control device for a starting friction element according to any one of claims 1 to 4,
The fastening force control device for a starting friction element, wherein the fastening force correction means gradually decreases the fastening force of the starting friction element. The starting friction element fastening force control device according to any one of claims 1 to 5,
The fastening force control device for a starting friction element, wherein the fastening force correcting means reduces the fastening force of the starting friction element in a step-like manner. The starting friction element fastening force control device according to any one of claims 1 to 6,
The fastening force control device for a starting friction element, wherein the fastening force correction means gradually increases the fastening force when the reduction correction is finished.

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