JP2005042828A - Control device of vehicle with infinite variable speed transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device, improved in fuel economy of a vehicle and durability of an infinitely variable speed transmission by properly reflecting the operating state of a clutch connected to the infinitely variable speed transmission to control the clamping pressure in the infinitely variable speed transmission. <P>SOLUTION: This control device of a vehicle including an infinitely variable speed transmission in which the clutch, the transmission torque capacity of which is varied with the engagement pressure, is serially connected to the infinitely variable speed transmission, the transmission torque capacity of which is varied with the clamping pressure for clamping a torque transmission member, and the clamping pressure is corrected according to the condition of the road surface where the vehicle runs. The control device includes: an operating condition determination means (step S101, S104, S202, S204) for determining the operating condition of the clutch; and a road surface corresponding correction pressure lead-out means (step S105, S201) for obtaining the correction pressure for correcting depending on the road surface condition on the basis of the operating condition determined by the operating condition determination means. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a control device for a vehicle including a continuously variable transmission whose torque capacity changes according to a clamping pressure.

  2. Description of the Related Art Conventionally known are power transmission devices such as a clutch, a brake, a belt type continuously variable transmission, and a traction type continuously variable transmission that transmits torque using the shearing force of traction oil. The transmission torque capacity needs to be a capacity capable of transmitting torque output from a power source such as an engine as necessary and sufficient. However, when the transmission torque capacity is increased, a large amount of power is consumed to generate a vertical load or a pressing force, and the fuel consumption is deteriorated, or the power transmission efficiency is lowered and the fuel consumption is deteriorated. There are inconveniences such as a decrease in durability. Therefore, the transmission torque capacity of a power transmission device such as a continuously variable transmission or the clamping pressure that determines the transmission torque capacity can transmit the input torque as necessary and mediates the transmission of torque such as a belt and a power roller. It is preferable that the member is as small as possible as long as the member does not slip.

  However, the driving state and road surface state of a vehicle equipped with a continuously variable transmission are not necessarily constant. For example, when the vehicle is traveling on a rough road, the driving wheel instantaneously applies grip force. In some cases, the vehicle slips and slips, and immediately after that, it comes in contact with the ground and recovers the grip force. In such a case, a large inertial force acts on the drive system from the power source such as the engine to the drive wheels. In addition, when the vehicle is running, a sudden acceleration operation in which the accelerator pedal is depressed suddenly and greatly, a sudden braking operation in which the brake pedal is depressed suddenly and greatly, and the like may be performed. Torque acts. Therefore, if the above-described transmission torque capacity or holding pressure in the continuously variable transmission is maintained constant, the torque acting on the continuously variable transmission becomes relatively excessive, and the rotating member in the continuously variable transmission Excessive slip may occur between the torque transmitting member.

  In order to avoid such a situation, it is necessary to set the transmission torque capacity or the clamping pressure in consideration of the torque acting from the drive wheel side in addition to the torque output from the power source. In that case, it is known to set the clamping pressure with a certain degree of safety factor so that the continuously variable transmission does not slip due to the influence of the road surface condition or the driving condition. That is, the clamping pressure in the continuously variable transmission is the theoretical pressure (basic clamping pressure) that is the lowest pressure that can transmit the input torque without causing the slip in the continuously variable transmission. The safety factor equivalent calculated by multiplying by the rate and the disturbance response equivalent set for the influence of road surface input and inertial force of the power source, etc., generated by changes in road surface condition and driving condition Or, a portion corresponding to a rough road) is added and set.

One example thereof is described in Patent Document 1. In the invention described in Patent Document 1, a so-called rough road-corresponding pinching pressure is applied to a belt pinching pressure corresponding to torque input from the power source side. That is, it is configured to determine whether the vehicle is in a driving state or a driven state, and to set a safety factor corresponding to each of the driving state and the driven state. Patent Document 2 describes an example of a detection device that can perform control corresponding to slipping of a continuously variable transmission.
JP 2001-330126 A (paragraph numbers 0017 to 0019) JP-A-4-285361 (paragraph number 0041, FIG. 10)

  In the device described in Patent Document 1 described above, the reverse input from the drive wheel side due to a change in the road surface condition, such as when the vehicle travels on a rough road, is reflected in the safety factor considered when setting the belt clamping pressure. Thus, the belt clamping pressure is set. However, the belt clamping pressure of the continuously variable transmission is not limited to the road surface state and vehicle driving state described above, and is generally disposed between the continuously variable transmission and the power source and is provided in a torque converter. It may also be affected by operating conditions. For example, the torque transmission capacity of the torque converter differs between when the lockup clutch is fully engaged and when the lockup clutch is released, and the inertial force generated by the engine with respect to the continuously variable transmission is determined by the spring of the lockup damper. The way of working is different. Therefore, the torque acting on the continuously variable transmission according to the torque input from the drive wheel side (or the output side) according to the road surface condition varies depending on the operating state of the lockup clutch. As a result, even if the belt clamping pressure is set with a safety factor that anticipates the road surface condition, slippage may occur in the continuously variable transmission, or conversely, the clamping pressure may become excessive.

  Thus, even if the clamping pressure of the continuously variable transmission is affected by the change in the operating state of the lockup clutch of the torque converter, if the safety factor against the slip of the continuously variable transmission is set uniformly, Unnecessarily increasing the pinching pressure can cause power loss, reducing the fuel consumption of the vehicle, and conversely, the pinching force is insufficient and the belt can easily slip, reducing the durability of the continuously variable transmission. There is sex.

  However, in the inventions described in Patent Document 1 and Patent Document 2 described above, no consideration is given to the influence of the operating state of the lock-up clutch of the torque converter, and there is still room for improvement in this respect.

  The present invention has been made paying attention to the above technical problem, and controls the clamping pressure in the continuously variable transmission by appropriately reflecting the operating state of the clutch connected to the continuously variable transmission. An object of the present invention is to provide a control device for a vehicle including a continuously variable transmission that can improve the fuel consumption of the vehicle and the durability of the continuously variable transmission.

  In order to achieve the above object, the present invention is characterized in that an operation state of a clutch connected to a continuously variable transmission is determined and an appropriate clamping pressure reduction control is performed according to the operation state. It is what. That is, according to the first aspect of the present invention, a continuously variable transmission whose transmission torque capacity changes according to the clamping pressure for clamping the torque transmission member is connected in series with a clutch whose transmission torque capacity changes according to the engagement pressure. And an operation state determination means for determining an operation state of the clutch in a vehicle control device including a continuously variable transmission that corrects the clamping pressure according to a road surface state on which the vehicle is traveling, and the road surface And a road surface corresponding correction pressure deriving unit that obtains a correction pressure of the clamping pressure that is corrected according to the state based on the operation state determined by the operation state determination unit.

  According to a second aspect of the present invention, in the first aspect of the invention, the road surface corresponding correction pressure deriving means is configured to correct the correction corresponding to the operation state before the change when the operation state of the clutch is in a transitional transition state. The control apparatus is configured to select a larger one of the pressure and the correction pressure corresponding to the changed operating state to obtain the correction pressure.

  According to the first aspect of the present invention, when the clamping pressure reduction control of the continuously variable transmission is executed and the clamping pressure is corrected according to the road surface condition where the vehicle is traveling, the continuously variable transmission is serially connected. The operating state of the connected clutch can be determined, and the correction pressure of the clamping pressure can be obtained based on the operating state. Therefore, it is possible to execute the clamping pressure reduction control that appropriately reflects the operation state of the clutch, avoiding excessive clamping pressure, reducing power loss, and improving vehicle fuel efficiency. .

  According to the second aspect of the present invention, when it is determined that the operation state of the clutch, such as a lock-up clutch provided in the torque converter, is a transitional state of change, the pinching before the change of the operation state of the clutch is performed. The pressure correction pressure is compared with the correction pressure of the clamping pressure after the change of the clutch operating state, and the larger correction pressure, that is, the correction pressure that increases the margin for slipping is selected, and the clamping pressure is selected. Correction pressure can be set. Therefore, even when the operating state of the clutch is in a transitional transition state, it is possible to set an appropriate correction pressure for clamping pressure, preventing or suppressing excessive slippage in the continuously variable transmission and improving durability. Can be made.

  Next, the present invention will be described based on specific examples. First, an example of a drive system including a power source and a continuously variable transmission targeted in the present invention will be described. FIG. 5 schematically shows an example of a drive system including a belt type continuously variable transmission 1. The continuously variable transmission 1 is connected to a power source 5 via a forward / reverse switching mechanism 2 and a fluid transmission mechanism 4 with a lock-up clutch 3.

  The power source 5 is composed of an internal combustion engine, or an internal combustion engine and an electric motor, or an electric motor. In the following description, the power source 5 is referred to as the engine 5. The fluid transmission mechanism 4 has a configuration similar to that of, for example, a conventional torque converter, and includes a pump impeller rotated by the engine 5, a turbine runner disposed to face the pump impeller, and a stator disposed therebetween. The turbine runner is rotated by supplying a spiral flow of fluid generated by a pump impeller to the turbine runner, and torque is transmitted.

  In such torque transmission through the fluid, inevitable slip occurs between the pump impeller and the turbine runner, which causes a reduction in power transmission efficiency. Therefore, the input member such as the pump impeller and the turbine runner A lock-up clutch 3 that directly connects an output side member such as the above is provided. The lock-up clutch 3 is configured to be controlled by hydraulic pressure, and is controlled to a fully engaged state, a fully released state, and a slip state that is an intermediate state between them, and the slip rotation speed can be appropriately controlled. It has become. Further, a damper (lock) is provided between the lockup clutch 3 and the fluid transmission mechanism 4 in order to mitigate vibrations and shocks caused by fluctuations in transmitted torque when the lockup clutch 3 is completely engaged. Up-damper) 3 'is provided.

  The forward / reverse switching mechanism 2 is a mechanism that is employed when the rotational direction of the engine 5 is limited to one direction, and outputs the input torque as it is or reversely outputs it. It is configured. In the example shown in FIG. 5, a double pinion type planetary gear mechanism is employed as the forward / reverse switching mechanism 2. That is, a ring gear 7 is arranged concentrically with the sun gear 6, and a pinion gear 8 meshed with the sun gear 6 and the pinion gear 8 and another pinion gear 9 meshed with the ring gear 7 are arranged between the sun gear 6 and the ring gear 7. The pinion gears 8 and 9 are held by the carrier 10 so as to rotate and revolve freely. A forward clutch 11 that integrally connects two rotating elements (specifically, the sun gear 6 and the carrier 10) is provided, and the direction of the torque that is output by selectively fixing the ring gear 7 There is provided a reverse brake 12 that reverses.

  The continuously variable transmission 1 has the same configuration as a conventionally known belt-type continuously variable transmission, and each of a driving pulley 13 and a driven pulley 14 arranged in parallel to each other includes a fixed sheave, a hydraulic type The movable sheave is moved back and forth in the axial direction by the actuators 15 and 16. Therefore, the groove width of each pulley 13 and 14 is changed by moving the movable sheave in the axial direction, and accordingly, the winding radius of the belt 17 wound around each pulley 13 and 14 (the effective diameter of the pulleys 13 and 14). ) Changes continuously, and the gear ratio changes steplessly. The drive pulley 13 is connected to a carrier 10 that is an output element in the forward / reverse switching mechanism 2.

  The hydraulic actuator 16 in the driven pulley 14 is supplied with hydraulic pressure (line pressure or its correction pressure) according to the torque input to the continuously variable transmission 1 via a hydraulic pump and a hydraulic control device (not shown). Yes. Therefore, each sheave in the driven pulley 14 holds the belt 17 so that tension is applied to the belt 17, and a holding pressure (contact pressure) between the pulleys 13, 14 and the belt 17 is ensured. . On the other hand, the hydraulic actuator 15 in the drive pulley 13 is supplied with pressure oil corresponding to the speed ratio to be set, and is set to a groove width (effective diameter) corresponding to the target speed ratio. .

  The driven pulley 14 is connected to a differential 19 through a gear pair 18, and torque is output from the differential 19 to driving wheels 20. Therefore, in the above drive mechanism, the lockup clutch 3 and the continuously variable transmission 1 are arranged in series between the engine 5 and the drive wheels 20.

  Various sensors are provided in order to detect the operation state (running state) of the vehicle on which the continuously variable transmission 1 and the engine 5 are mounted. That is, a turbine rotation speed sensor 21 that detects an input rotation speed (rotation speed of the turbine runner) to the continuously variable transmission 1 and outputs a signal, and an input rotation speed that detects the rotation speed of the drive pulley 13 and outputs a signal. A sensor 22, an output rotation speed sensor 23 that detects the rotation speed of the driven pulley 14 and outputs a signal, and a hydraulic pressure sensor 24 that detects the pressure of the hydraulic actuator 16 on the driven pulley 14 side for setting the belt clamping pressure are provided. ing. Although not specifically shown, an accelerator opening sensor that detects a depression amount of the accelerator pedal and outputs a signal, a throttle opening sensor that detects a throttle valve opening and outputs a signal, and a brake pedal are depressed. A brake sensor or the like that outputs a signal in case is provided.

  A transmission is used to control the engagement / release of the forward clutch 11 and the reverse brake 12, the control of the clamping force of the belt 17, the control of the transmission ratio, and the control of the lockup clutch 3. An electronic control device (CVT-ECU) 25 is provided. The electronic control unit 25 is configured mainly by a microcomputer as an example, performs calculations according to a predetermined program based on input data and data stored in advance, and various states such as forward, reverse, or neutral, Further, it is configured to execute control such as setting of a required clamping pressure, setting of a gear ratio, engagement / release of the lock-up clutch 3, and slip rotation speed.

  Here, an example of data (signal) input to the transmission electronic control unit 25 is as follows: a signal of the input rotation speed (input rotation speed) Nin of the continuously variable transmission 1 and an output of the continuously variable transmission 1. A signal of the rotational speed (output rotational speed) No is input from the corresponding sensor. An engine electronic control unit (E / G-ECU) 26 for controlling the engine 5 receives a signal of an engine speed Ne, an engine (E / G) load signal, a throttle opening signal, an accelerator pedal (not shown). )), The accelerator opening signal is input.

  According to the continuously variable transmission 1, the engine speed, which is the input speed, can be controlled steplessly (in other words, continuously), so that the fuel efficiency of a vehicle equipped with the engine speed can be improved. For example, the target driving force is obtained based on the required driving amount represented by the accelerator opening and the vehicle speed, and the target output necessary to obtain the target driving force is obtained based on the target driving force and the vehicle speed. The engine speed for obtaining the target output with the optimum fuel consumption is obtained based on a map prepared in advance, and the gear ratio is controlled so as to be the engine speed.

  In order not to impair such an improvement in fuel consumption, the power transmission efficiency in the continuously variable transmission 1 is controlled to a good state. Specifically, the torque capacity of the continuously variable transmission 1, that is, the belt clamping pressure, can transmit the target torque determined based on the engine torque, and the belt clamping pressure is as low as possible without causing the belt 17 to slip. It is controlled to become. For example, the belt clamping pressure controls the continuously variable transmission 1 in a so-called unsteady traveling state such as when acceleration / deceleration is performed relatively frequently or when traveling on a rough road with uneven or uneven road surfaces. It is set to a relatively high pressure such as the line pressure that is the total source pressure in the hydraulic system or its correction pressure.

  On the other hand, in steady running conditions such as running on a flat road at a certain speed or above, or in a quasi-steady running condition equivalent to this, the lowest pressure that can transmit input torque without slipping, that is, the limit clamping pressure In order to detect this, the belt clamping pressure is gradually reduced. The belt clamping pressure is set to a belt clamping pressure obtained by adding a predetermined safety factor or a pressure for setting a margin transmission torque for slipping to the detected limit clamping pressure.

  When the vehicle is traveling, the torque output from the engine 5, the torque input from the drive wheels 20, the gear ratio, and the like vary variously based on the gradient of the traveling path, unevenness, acceleration / deceleration operation, and the like. And according to such a change, the operation state of the lockup clutch 3 provided in the fluid transmission mechanism 4 connecting the engine 5 and the continuously variable transmission 1 is also in the fully engaged state, the fully released state, Or it changes with the torque fuse control state. At this time, the rotational speed on the input side of the continuously variable transmission 1 changes with a change in the operating state of the lockup clutch 3, resulting in the generation of inertia torque by the engine 5, or the continuously variable transmission 1. There are cases where the influence of the inertia torque acting on the motor changes.

  For example, when the lock-up clutch 3 is in a fully released state, the connection state between the engine 5 and the continuously variable transmission 1 is not completely integrated, and the rotational speed on the drive wheel 20 side is caused by a change in the road surface state. Even if the change occurs, the fluid transmission mechanism 4 slips, so that the change is not easily transmitted to the engine 5, so that the inertia torque by the engine 5 is less likely to act on the rotation change on the output side.

  On the other hand, when the lock-up clutch 3 is in the fully engaged state, the engine 5 and the continuously variable transmission 1 rotate almost integrally. Therefore, when the rotational speed on the drive wheel 20 side changes, the engine correspondingly changes. 5, but the inertial mass of the engine 5 is large, so that a large inertia torque by the engine 5 acts on the continuously variable transmission 1. This inertia torque becomes a reaction force against the input torque of the continuously variable transmission 1, and slipping may occur in the continuously variable transmission 1.

  If the belt clamping pressure of the continuously variable transmission 1 is set in response to disturbances such as inertia torque generated in accordance with such changes in the operation state of the lockup clutch 3, the continuously variable transmission 1 due to these disturbances is set. In order to prevent excessive slippage, the situation in which the belt clamping pressure is unnecessarily increased can be avoided. Therefore, the control device according to the present invention is configured to control the belt clamping pressure in accordance with (or based on) the operating state of the lockup clutch 3 provided in the fluid transmission mechanism 4. A specific example of the control will be described below.

  FIG. 1 is a flowchart showing an example. In FIG. 1, first, the operating state of the lockup clutch 3 is detected (step S101). The operation state of the lock-up clutch 3 determined in the control example according to the present invention includes the “lock-up ON” state in which the lock-up clutch 3 is completely engaged and the lock-up clutch 3 is completely released. There are a “lock-up OFF” state and a “torque fuse control” state in which the lock-up clutch 3 functions as a torque fuse.

  The lock-up clutch 3 provided in the fluid transmission mechanism 4 is generally released in a so-called converter region in which the fluid transmission mechanism 4 acts as a torque converter that amplifies torque, such as during low-speed running or sudden acceleration. The fluid transmission mechanism 4 acts as a fluid clutch in an engaged state, such as during high-speed stable running, and is engaged in a so-called coupling region that does not require torque amplification, and directly outputs the output from the engine 5 continuously. It transmits to the transmission 1 and plays a role of preventing power loss in the fluid transmission mechanism 4.

  The lockup clutch 3 is configured to perform torque fuse control that functions as a so-called torque fuse for the continuously variable transmission 1. The torque fuse control is control for limiting the torque acting on the continuously variable transmission 1 by the lock-up clutch 3. When the torque acting on the drive system increases, for example, the torque fuse control precedes the continuously variable transmission 1. In this control, the transmission torque capacity, that is, the engagement pressure of the lockup clutch 3 is set so that the lockup clutch 3 slips. In other words, this is control for setting the margin of the transmission torque capacity until slippage occurs to be smaller in the lockup clutch 3 than in the continuously variable transmission 1.

  When the operation state of the lockup clutch 3 is detected in step S101, subsequently, the input shaft rotational speed Nin of the continuously variable transmission 1 and the output shaft rotational speed Nout of the continuously variable transmission 1 are measured. A speed ratio γ of the continuously variable transmission 1 is calculated from Nin and Nout (step S102). Subsequently, it is determined whether or not the clamping pressure reduction control for reducing the clamping pressure is being performed in order to detect the limit clamping pressure (step S103). If negative determination is made in step S103 because the clamping pressure reduction control is not being executed, the process proceeds to step S108, and this routine is once terminated.

  On the other hand, if the stepless transmission 1 is under the clamping pressure reduction control and the determination in step S103 is affirmative, the process proceeds to step S104, and the operating state of the lockup clutch 3 is changed transiently. It is determined whether or not it is in a state. If the operation state of the lock-up clutch 3 is not a transitional state of change, and a negative determination is made in step S104, the process proceeds to step S105, and the operation state of the lock-up clutch 3 and the above-described step S102 are calculated. Based on the transmission gear ratio γ of the continuously variable transmission 1, the corrected hydraulic pressure corresponding to the rough road is calculated. Then, the reduced clamping pressure to be reduced, which is corrected based on the corrected hydraulic pressure corresponding to the rough road calculated in step S105, is calculated (step S106), and then this routine is temporarily ended.

  The corrected hydraulic pressure and the reduced clamping pressure corresponding to the rough road calculated in the above steps S105 and S106 are obtained by the following calculation formulas, respectively.

Corrected hydraulic pressure for rough road = (For rough road SF-1) x Theoretical clamping pressure Decrease clamping pressure = Theoretical clamping pressure + Corrected hydraulic pressure for rough road
− (Centrifugal oil pressure + return spring equivalent oil pressure)
Theoretical clamping pressure = positive input torque · cos α / (2 · µ · Rin · Ap)
Here, α is a depression angle of the belt 17 at the driving pulley 13 and the driven pulley 14, Rin is a winding diameter (winding radius) of the belt 17 in the driving pulley 13, and Ap is a piston area of the hydraulic actuator 16. Moreover, the rough road corresponding part SF which is the safety factor with respect to the slip of the continuously variable transmission 1 is, for example, a schematic diagram (map) showing setting of the rough road corresponding part SF by the gear ratio γ, an example of which is shown in FIG. FIG. 4 shows an example thereof, which can be determined by superimposing a schematic diagram (map) showing the setting of the rough road correspondence SF in the lockup state.

  On the other hand, when the operation state of the lock-up clutch 3 is a transitional transition state, if the determination in step S104 is affirmative, the process proceeds to step S107, and an example thereof is shown in the flowchart of FIG. “Predetermined control 1” is executed. The control example will be described with reference to FIG. 2. First, in step S201, the corrected hydraulic pressure corresponding to each bad road according to the speed ratio γ of the continuously variable transmission 1 is calculated. That is, according to the gear ratio γ when the operation state of the lockup clutch 3 is “lockup ON” and “lockup OFF” from the maps shown in FIG. 3 and FIG. Each rough road corresponding SF is set, and the corrected hydraulic pressure corresponding to the rough road is calculated.

  Next, it is determined whether or not the operation state of the lock-up clutch 3 is a transient state from “lock-up OFF” to “lock-up ON” or “lock-up ON” to “lock-up OFF” ( Step S202). The operation state of the lock-up clutch 3 is not a transition state from “lock-up OFF” to “lock-up ON”, and is not a transition state from “lock-up ON” to “lock-up OFF”. When a negative determination is made in S202, the process proceeds to step S204, and the operation state of the lockup clutch 3 is changed from “torque fuse control” to “lockup ON”, or from “lockup ON” to “torque fuse control”. It is determined whether or not this is a transient state.

  Since the operating state of the lockup clutch 3 is a transient state from “torque fuse control” to “lockup ON” or from “lockup ON” to “torque fuse control”, the determination is positive in step S204. If YES in step S205, the flow proceeds to step S205, and the corrected hydraulic pressure corresponding to the rough road when the operation state of the lockup clutch 3 is “lockup ON” calculated in step S201 is selected. Then, the process returns to step S106 in the flowchart shown in FIG.

  On the other hand, the operation state of the lock-up clutch 3 is not a transient state from “torque fuse control” to “lock-up ON”, and is not a transient state from “lock-up ON” to “torque fuse control”. If the determination in step S204 is negative, the process proceeds to step S206, and the corrected hydraulic pressure corresponding to the rough road when the operation state of the lockup clutch 3 is “lockup OFF” calculated in step S201 is selected. The Thereafter, the routine of the predetermined control 1 shown in FIG. 2 is once ended, and the process returns to step S106 in the flowchart shown in FIG.

  On the other hand, the operation state of the lock-up clutch 3 is a transient state from “lock-up OFF” to “lock-up ON” or “lock-up ON” to “lock-up OFF”. If the determination in step S202 is affirmative, the process proceeds to step S203, and the rough road correspondence is calculated when the operation state of the lockup clutch 3 calculated in step S201 is “lockup OFF” and “lockup ON”. The corrected hydraulic pressure corresponding to the rough road is selected, whichever is larger.

  As illustrated in the schematic diagram (map) showing the setting of the rough road corresponding SF in the lock-up state in FIG. 4, the operation state of the lock-up clutch 3 is “lock-up ON” and “lock-on”. This is because the rough road corresponding SFs in the case of “up OFF” are different in magnitude depending on the magnitude of the secondary shaft torque of the continuously variable transmission 1. Specifically, in a region where the secondary shaft torque is small, so-called converter region, the rough road corresponding SF in the “lock-up ON” state is set larger than the rough road corresponding SF in the “lock-up OFF” state. On the other hand, in a region where the secondary shaft torque is large, so-called coupling region, the rough road corresponding SF in the “lock-up OFF” state is better than the rough road corresponding SF in the “lock-up ON” state. This is because they are set large and their sizes are reversed.

  Therefore, by controlling as in step S203, the operation state of the lockup clutch 3 transitions from “lockup OFF” to “lockup ON” or from “lockup ON” to “lockup OFF”. Even in the state, the corrected hydraulic pressure corresponding to the rough road required for setting the reduced clamping pressure is the corrected hydraulic pressure corresponding to the rough road when “lock-up OFF” and the rough road when “lock-up ON”. Of the corresponding corrected hydraulic pressures, the larger one is always selected regardless of the magnitude of the secondary shaft torque at that time. In other words, the corrected hydraulic pressure corresponding to the rough road is always set by selecting the corrected hydraulic pressure corresponding to the rough road on the safe side where the safety factor is always large, that is, the margin for slipping in the continuously variable transmission 1 is large. Therefore, excessive belt slippage in the continuously variable transmission 1 can be prevented or suppressed.

  When the corrected hydraulic pressure corresponding to the rough road is selected in step S203, the routine of the predetermined control 1 shown in FIG. 2 is once ended, and the process returns to step S106 in the flowchart shown in FIG.

  As described above, according to the control device according to the present invention configured to execute the control shown in FIGS. 1 and 2, the clamping pressure of the continuously variable transmission 1 depends on the road surface state in which the vehicle is traveling. When the clamping pressure is corrected and the clamping pressure reduction control is executed, the operating state of the lockup clutch 3 is determined, and an appropriate rough road corresponding SF is determined according to (or based on) the determined operating state. The corrected hydraulic pressure corresponding to the rough road is set. As a result, even if the operating state of the lock-up clutch 3 changes, it is possible to execute the clamping pressure reduction control that appropriately reflects the operating state, thereby reducing the clamping pressure as much as possible and causing excessive clamping pressure. This can improve the fuel efficiency of the vehicle. Even when the operation state of the lock-up clutch 3 is in a transitional transition state, the corrected hydraulic pressure corresponding to the rough road always increases the margin for slipping in the continuously variable transmission 1, corresponding to the rough road on the safe side. Therefore, excessive belt slip in the continuously variable transmission 1 can be prevented or suppressed, and durability of the continuously variable transmission can be improved.

  Here, the relationship between each of the above specific examples and the present invention will be briefly described. Each of the functional means of steps S101, S104, S202, and S204 described above corresponds to the operation state determination means in the invention of claim 1. The functional means in steps S105 and S201 correspond to the road surface corresponding correction pressure deriving means in the first aspect of the invention. Further, the functional means of step S203 corresponds to the functional means added to the road surface corresponding correction pressure deriving means of claim 1 in the invention of claim 2.

  Note that the present invention is not limited to the above specific example, and can be applied to a control device for a traction type continuously variable transmission in addition to a belt type continuously variable transmission. In addition, the clutch in the present invention may be a clutch that is arranged in series with the continuously variable transmission and has a variable torque capacity including engagement and disengagement. Therefore, in addition to the lock-up clutch, the clutch is completely slipped when starting. The clutch may be a so-called start clutch that can be engaged with the clutch. In short, any clutch that can change the transmission state of torque may be used. Further, these clutches may be provided with a damper, and the operation state determination means in the present invention may determine the characteristics of the damper and the transmission torque capacity.

  Further, in the above specific example, when the operation state of the lockup clutch 3 is in a transitional transition state, the corrected hydraulic pressure corresponding to the rough road required for setting the reduced pinching pressure is set to “lockup OFF” in FIG. ”And“ Lock-up ON ”, and the value obtained by selecting the larger one corresponding to the rough road corresponding SF at the time of“ Lock-up ON ”was used. It is good also as a value calculated | required using the map which selected those larger ones from the diagram which shows SF corresponding to rough roads at the time.

  Further, in the above specific example, the rough road corresponding SF, and the corrected hydraulic pressure corresponding to the rough road corresponding to each operation state of the lockup clutch 3 or a transient state thereof, as shown in FIG. 3 and FIG. Although the value obtained using a map or the like is used, it may be obtained using, for example, a three-dimensional map shown in FIG. 3 and FIG. 4 together, or the vehicle running state, vehicle The value may be calculated and obtained based on the road surface state where the vehicle is traveling, the operation state of the lockup clutch 3, and the like. Furthermore, in the above specific example, the corrected hydraulic pressure corresponding to the rough road is a value calculated from parameters such as the rough road corresponding SF obtained using the map. The corrected oil pressure may be a value obtained from a map or the like, in addition to being obtained by calculation.

It is a flowchart for demonstrating an example of control by the control apparatus of this invention. It is a flowchart for demonstrating an example of control by the control apparatus of this invention. It is the schematic which shows the relationship between gear ratio (gamma) and rough road corresponding | compatible part SF for demonstrating an example of the control by the control apparatus of this invention. It is the schematic which shows the relationship between the operation state of a clutch and rough road corresponding | compatible part SF for demonstrating an example of control by the control apparatus of this invention. It is a figure which shows typically an example of the drive system containing the continuously variable transmission made into object by this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Continuously variable transmission, 3 ... Lock-up clutch, 5 ... Engine (power source), 13 ... Drive pulley, 14 ... Drive pulley, 15, 16 ... Hydraulic actuator, 17 ... Belt, 20 ... Drive wheel, 25 ... Shift Electronic control unit for machine (CVT-ECU).

Claims (2)

A continuously variable transmission having a transmission torque capacity that changes in accordance with the clamping pressure that clamps the torque transmission member is connected in series to a clutch that changes in transmission torque capacity in accordance with the engagement pressure. In a vehicle control device provided with a continuously variable transmission that corrects according to the road surface state where the vehicle is traveling,
An operation state determination means for determining an operation state of the clutch;
A continuously variable transmission comprising: a road surface corresponding correction pressure deriving unit that obtains a correction pressure of the clamping pressure corrected according to the road surface state based on the operation state determined by the operation state determination unit. Control device for a vehicle equipped with a machine.   The road surface corresponding correction pressure deriving means includes the correction pressure corresponding to the operation state before the change and the correction pressure corresponding to the operation state after the change when the operation state of the clutch is in a transitional transition state. 2. The control apparatus for a vehicle including a continuously variable transmission according to claim 1, wherein the correction pressure is obtained by selecting a larger one.

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