JP4254180B2 - Transmission control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transmission control device including a clutch and a continuously variable transmission mechanism, and in particular, based on the transmission state of torque by the clutch, such as the engagement state of the clutch, the transmission torque capacity due to the clamping pressure of the continuously variable transmission mechanism, The present invention relates to a device to be controlled.
[0002]
[Prior art]
Conventionally known belt type continuously variable transmission mechanisms and traction type (toroidal type) continuously variable transmission mechanisms are configured to transmit torque using frictional force or shearing force of traction oil. Therefore, the transmission torque capacity increases or decreases according to the vertical load at the torque transmission site. In the belt-type continuously variable transmission mechanism, the vertical load is the belt clamping pressure of the pulley around which the belt is wound. In the traction-type continuously variable transmission mechanism, the vertical load is the load that holds the power roller between the input disk and the output disk. It is clamping pressure.
[0003]
Increasing the transmission torque capacity by increasing the clamping pressure can avoid slipping of the belt, power roller, etc. even if the torque acting on the continuously variable transmission mechanism increases or decreases. On the other hand, there is a disadvantage that the power consumed to increase the clamping pressure is increased, the fuel consumption is deteriorated, and the durability of the apparatus is lowered. In other words, the clamping pressure is preferably a pressure corresponding to the input torque. For this reason, in the invention described in, for example, Japanese Patent Application Laid-Open No. 60-191822 (Japanese Patent Publication No. 6-47350) (Patent Document 1). The operation state of the slip clutch is controlled based on the driving state of the vehicle, and the belt pressing force (belt clamping force) in the belt type continuously variable transmission mechanism is controlled according to the control signal of the slip clutch. ing.
[0004]
Japanese Patent No. 2653249 (Patent Document 2) discloses an apparatus configured to increase the line pressure to prevent belt slip when the torque converter is in the converter region.
[0005]
[Patent Document 1]
JP 60-191822 A (page 3)
[Patent Document 2]
Japanese Patent No. 2653249 (Claims)
[0006]
[Problems to be solved by the invention]
The operation state in the invention described in the above publication includes the throttle valve opening and the engine speed, and the slip amount of the clutch is controlled based on the detection signal. Therefore, in the conventional invention described in the above publication, the belt clamping pressure is controlled based on the output of the engine, in other words, the input to the continuously variable transmission mechanism.
[0007]
However, when the vehicle is running, the power transmission system from the engine to the drive wheels via the clutch and continuously variable transmission mechanism is connected so that the whole rotates integrally. The torque acting on the continuously variable transmission mechanism is not limited to the torque input from the engine side. Torque is also input to the continuously variable transmission mechanism from the drive wheel side where the rotational speed is changed according to the road surface condition. May be. Since the conventional device described in the above publication is not configured to perform control in consideration of the torque input from the output side, the pinching pressure is not necessarily suitable for the traveling state. Excess or deficiency may occur, and as a result, slipping may occur or power transmission efficiency may be reduced.
[0008]
The present invention has been made paying attention to the above technical problem, and provides a transmission control device capable of appropriately setting a transmission torque capacity of a continuously variable transmission mechanism in response to so-called road surface input. It is for the purpose.
[0009]
[Means for Solving the Problem and Action]
To achieve the above object, the invention of claim 1, together with the controllable clutch transmission state of the torque is connected to the output side of the power source, the continuously variable transmission mechanism on the output side of the clutch connected, in the control apparatus for a transmission which controls the transmission torque capacity of the continuously variable transmission mechanism according to the torque transmission state of the clutch, the transmission torque capacity is either the power source to the continuously variable transmission configuration It includes a positive input torque component determined based on the torque et type and the road surface input component based on the torque input from the output side, and means for detecting the actual slip amount of the clutches, among the transmission torque capacity the road surface input frequency, which is a control apparatus characterized by comprising an auxiliary Seite stage for smaller actual slip amount of the clutch is large.
[0010]
As described in claim 1 , the correcting means can be configured to set the transmission torque capacity for the road surface input to be smaller as the actual slip amount of the clutch is larger.
[0012]
Thus the inventions of claim 1, as a sum of the transmission torque capacity is a positive input torque component and the road surface input frequency of the continuously variable transmission mechanism is set by such clamping pressure, the road surface input content, the actual slip of the clutch Is corrected based on As an example, the transmission torque capacity for the road surface input is increased as the transmitted torque such as the actual slip amount is small. Therefore, the transmission torque capacity due to the clamping pressure of the continuously variable transmission mechanism is set to an amount corresponding to the road surface state or road surface input, and is optimized.
[0013]
According to a second aspect of the present invention, there is provided a transmission in which a clutch capable of controlling a torque transmission state is connected to an output side of a power source, and a transmission torque capacity of the continuously variable transmission mechanism is set based on a predetermined safety factor. in the control device, means for detecting the actual slip amount of the clutch, the safety factor, before Symbol control it, characterized in that a correcting means for setting the smaller value the larger the real slip of the clutch Device.
As described in claim 2 , the correcting means can be configured such that the safety factor is reduced as the actual slip amount of the clutch increases.
[0014]
Therefore, in the invention of claim 2, the transmission torque capacity of the continuously variable transmission mechanism is set in consideration of a predetermined safety factor, and the safety factor is corrected based on the actual slip amount in the clutch. As an example, when the torque transmitted by the clutch is reduced, the safety factor is reduced. Therefore, even if an input from the output side of the continuously variable transmission mechanism occurs due to a change in the road surface state, slippage at the clutch is likely to occur, and the torque acting on the continuously variable transmission mechanism is limited. Therefore, slippage of the continuously variable transmission mechanism can be avoided, and at the same time, the transmission torque capacity due to the clamping pressure or the like is set as low as possible.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described based on specific examples. First, a description will be given of a vehicle transmission including a continuously variable transmission mechanism and a control system thereof as a subject of the present invention. FIG. 3 schematically shows a transmission including a belt type continuously variable transmission mechanism 1. The continuously variable transmission mechanism 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.
[0016]
The power source 5 is constituted by an internal combustion engine, or an internal combustion engine and an electric motor, or an electric motor, and is mainly a driving member that generates power for traveling. In the following description, the power source 5 is referred to as the engine 5.
[0017]
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 the pump impeller to the turbine runner, and torque is transmitted.
[0018]
In such torque transmission through the fluid, inevitable slip occurs between the pump impeller and the turbine runner, and this 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 corresponds to the clutch according to the present invention, and is configured to be controlled by hydraulic pressure. The lock-up clutch 3 is controlled to a fully engaged state, a fully released state, and a slip state that is an intermediate state between them. The slip rotation speed can be appropriately controlled.
[0019]
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. 3, 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.
[0020]
The continuously variable transmission mechanism 1 has the same configuration as a conventionally known belt-type continuously variable transmission, and includes a drive pulley 13 as an input member and a driven pulley 14 as an output member that are arranged in parallel to each other. The fixed sheave and the movable sheave that is moved back and forth in the axial direction by the hydraulic actuators 15 and 16 are configured. 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.
[0021]
The hydraulic actuator 16 in the driven pulley 14 is supplied with a hydraulic pressure (line pressure or its correction pressure) corresponding to the torque input to the continuously variable transmission mechanism 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. .
[0022]
The transmission torque capacity of the continuously variable transmission mechanism 1 is a capacity corresponding to the belt clamping pressure. A hydraulic pressure sensor 23 for detecting the hydraulic pressure for setting the clamping pressure, that is, the hydraulic pressure in the hydraulic actuator 16 is provided. 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. .
[0023]
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.
[0024]
Various sensors are provided to detect the operation state (running state) of a vehicle on which the continuously variable transmission mechanism 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 mechanism 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 and a wheel speed sensor 24 that detects the rotational speed of the drive wheel 20 and outputs a signal are provided. 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.
[0025]
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.
[0026]
Here, examples of data (signals) input to the transmission electronic control unit 25 are shown as follows: a signal of the input rotational speed Nin of the continuously variable transmission mechanism 1 and a signal of the output rotational speed No of the continuously variable transmission mechanism 1. Etc. are entered. Further, an engine electronic control unit (E / G-ECU) 26 for controlling the engine 5 receives an engine speed Ne signal, an engine (E / G) load (torque) signal, a throttle opening signal, an accelerator pedal. An accelerator opening signal, which is the amount of depression (not shown), is input.
[0027]
Furthermore, the above-mentioned vehicle is provided with an anti-lock brake system (ABS) for avoiding wheel lock. A slip determination signal of the drive wheels (tires) 20 is input from the electronic control unit (ABS-ECU) 27 constituting the antilock brake system to the transmission electronic control unit 25.
[0028]
According to the continuously variable transmission mechanism 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 this 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.
[0029]
In order not to impair such an improvement in fuel consumption, the power transmission efficiency in the continuously variable transmission mechanism 1 is controlled to a good state. Specifically, the torque capacity of the continuously variable transmission mechanism 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. Be controlled.
[0030]
However, the torque output from the engine 5 when the vehicle is traveling, the torque input from the drive wheels 20 (road surface input), the gear ratio, and the like are varied based on the gradient and unevenness of the traveling road surface, acceleration / deceleration operations, and the like. To change. If the clamping pressure is set in response to such a change, a situation in which the clamping pressure is unnecessarily increased is avoided. Therefore, the control device according to the present invention sets the transmission torque capacity of the continuously variable transmission mechanism 1 in accordance with the torque transmission state of the clutch (that is, the lockup clutch 3) connected in series to the continuously variable transmission mechanism 1. The corresponding clamping pressure is controlled as follows.
[0031]
FIG. 1 shows an example of such control. First, as a torque transmission state of the lock-up clutch 3, it is determined whether or not the fluid transmission mechanism 4 is in a torque converter state (T / C state) (step). S1). Here, the torque converter state is a state where the lock-up clutch 3 is completely released and no torque is transmitted by the lock-up clutch 3. Therefore, it does not matter whether the fluid transmission mechanism 4 is in the converter range or the coupling range.
[0032]
If the determination in step S1 is affirmative, the clamping pressure in the torque converter state, that is, the clamping pressure in a state where the lockup clutch 3 is completely released is set (step S2).
[0033]
The hydraulic pressure Pd for setting the belt clamping pressure in the continuously variable transmission mechanism 1 is obtained by the formula (1) or formula (2).
Pd = Pth · SF−Pcf−Psp + Per (1)
Pd = Pth−Pcf−Psp + Per + Prd (2)
Pth = Positive input torque ・ cos α / (2 ・ μ ・ Rin ・ Piston area)
[0034]
Here, Pth is a theoretical oil pressure, SF is a predetermined safety factor, Pcf is a centrifugal oil pressure, Psp is a return spring equivalent pressure, Per is an error corresponding oil pressure, Prd is a road surface input corresponding oil pressure, and α is each pulley 13,14. The depression angle Rin of the belt 17 is the diameter of the belt 17 (winding radius) of the drive pulley 13.
[0035]
In a state where the lock-up clutch 3 is completely released, the connection state between the engine 5 and the continuously variable transmission mechanism 1 is a so-called weak state. Since the mechanism 4 slips, the engine 5 hardly changes in rotation. Therefore, the inertia torque by the engine 5 hardly acts on the output-side rotation change. Therefore, in step S2, the safety factor SF in the above equation (1) is reduced to relatively reduce the clamping pressure. Alternatively, as shown by the formula (2), the latter road surface input corresponding hydraulic pressure Prd is reduced among the positive input torque corresponding to the torque input from the engine 5 side and the road surface input input from the output side. The clamping pressure is set relatively low.
[0036]
Here, FIG. 2 shows an example of the relationship between the amount corresponding to the road surface input in the clamping pressure and the engagement state (torque transmission state) of the lock-up clutch 3. The pinching pressure corresponding to the road surface input shown here is determined in advance by experiments or the like, and is set to a larger value as it is closer to the complete engagement state (lock-up state: L / U state).
[0037]
On the other hand, if a negative determination is made in step S1, it is determined whether or not the lockup clutch 3 is in a slip state (step S3). Here, the slip state is a state other than a completely released state where no torque is transmitted and a completely engaged state where there is no relative rotational speed between the input side member and the output side member. Therefore, in the lockup clutch 3 configured to perform the slip control by setting the target slip rotational speed, the slip control state and the transient state when the change control between the states is performed. Is included in the slip state. On the other hand, in the lock-up clutch 3 that does not perform the slip control, for example, the slip control is prohibited due to the occurrence of judder or the like, the fully engaged state and the fully released state A transient state between the two corresponds to a slip state.
[0038]
If the determination in step S3 is affirmative because the lock-up clutch 3 is in the slip state, the actual slip amount in the lock-up clutch 3 is calculated (step S4). The actual slip amount can be obtained as a difference between the engine speed (input speed) and the turbine speed (output speed) detected by the turbine speed sensor 21.
[0039]
Next, the clamping pressure depending on the actual slip amount is set (step S5). That is, as shown in FIG. 2, as the slip amount is larger, the road surface input portion of the clamping pressure is set to be smaller. Therefore, the value applied to the positive input torque is smaller, so that the belt clamping pressure as a whole is reduced. Set to a small value. When the clamping pressure is controlled based on the above formula (1), the belt clamping pressure is set to a predetermined pressure by setting the safety factor SF to a small value.
[0040]
On the other hand, if a negative determination is made in step S3, the clamping pressure when the lock-up clutch 3 is in the fully engaged state (low-up state: L / U state) is set (step S6). That is, if a negative determination is made in step S3, the lock-up clutch 3 is not fully released and is not slipping, so that it is completely engaged. Pressure is set.
[0041]
That is, if the lockup clutch 3 is completely engaged, the engine 5 and the drive wheel 20 are connected in a so-called strong state, and these rotate substantially integrally. Therefore, if the rotational speed of the drive wheel 20 changes due to a change in the road surface state, the rotational speed of the engine 5 tends to change correspondingly. Therefore, a large inertia torque due to a large moment of inertia of the engine 5. Will occur.
[0042]
Therefore, in this state, it is expected that the torque acting on the continuously variable transmission mechanism 1 increases with the road surface input. Therefore, by increasing the road surface input portion of the clamping pressure, the belt clamping pressure is increased as a whole. To do. Specifically, the clamping pressure is set by adding the road surface input correspondence in the L / U state shown in FIG. 2 to the positive input torque, and as a result, the belt clamping pressure becomes relatively high. Alternatively, the safety factor SF described above is set to a relatively large value, and the belt clamping pressure becomes relatively high.
[0043]
As described above, the closer the torque transmission state of the lock-up clutch 3 is to a so-called strong transmission state (rigid transmission state) without slipping, the more strongly the engine 5 and the drive wheels 20 are connected, and the change in the road surface. The torque acting on the continuously variable transmission mechanism 1 increases with the input to the drive wheels 20 caused by the above. In the control device according to the present invention that performs the control shown in FIG. 1 above, the belt clamping pressure is set in accordance with the torque resulting from such road surface input, so the belt clamping pressure includes the road surface state. As a result, the belt slip can be effectively avoided, and at the same time, the belt clamping pressure becomes excessive and the fuel consumption can be avoided. Further, it is possible to prevent the durability of the continuously variable transmission mechanism 1 from being lowered.
[0044]
Here, the relationship between the above specific example and the present invention will be briefly described. The functional means of steps S2, S5 and S6 shown in FIG. 1 correspond to the correcting means of the present invention.
[0045]
The present invention is not limited to the above specific example, and the continuously variable transmission mechanism may be a traction type continuously variable transmission mechanism in addition to the belt type, and in series with the continuously variable transmission mechanism. The clutch to be connected may be a so-called start clutch that can be completely engaged through a slip state at the start, in addition to the above-described lock-up clutch. In short, any clutch that can change the torque transmission state may be used. . In the above specific example, the slip amount is obtained from the actual measurement value. Instead, the slip amount may be estimated from a predetermined parameter, or a slip control command value may be used.
[0046]
【The invention's effect】
As described above, according to the first and second aspects of the present invention, the transmission torque capacity due to the clamping pressure of the continuously variable transmission mechanism is set to an appropriate value according to the road surface condition or road surface input. Therefore, it is possible to effectively prevent or suppress slippage in a continuously variable transmission mechanism where the pinching pressure is insufficient and a decrease in power transmission efficiency due to excessive pinching pressure, and consequently the fuel consumption of a vehicle equipped with the transmission And the durability of the transmission can be improved.
[Brief description of the drawings]
FIG. 1 is a flowchart illustrating an example of control by a control device of the present invention.
FIG. 2 is a diagram schematically showing an example of a clamping pressure corresponding to a torque transmission state of a clutch and a road surface input.
FIG. 3 is a diagram schematically showing a drive system and a control system of a vehicle equipped with a power transmission device according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Continuously variable transmission mechanism, 5 ... Engine (power source), 13 ... Drive pulley, 14 ... Driven pulley, 15, 16 ... Actuator, 17 ... Belt, 20 ... Drive wheel, 25 ... Electronic control unit for transmission (CVT) -ECU).

Claims (2)

With controllable clutch transmission state of the torque is connected to the output side of the power source, continuously variable transmission mechanism is connected to the output side of the clutch, the continuously variable in accordance with the torque transmission state of the clutch In a transmission control device that controls transmission torque capacity of a transmission mechanism,
The transmission torque capacity includes a road surface input component based on the torque input from the output side of the continuously variable transmission positive input torque component determined based on the torque which the input power source or al the structure, and
It means for detecting the actual slip amount of the clutches,
The road surface input frequency of the transmission torque capacity, an auxiliary Seite stage for smaller actual slip amount of the clutch is large
Control device for a transmission, characterized in that it comprises a. In a transmission control device in which a clutch capable of controlling the torque transmission state is connected to the output side of the power source, and the transmission torque capacity of the continuously variable transmission mechanism is set based on a predetermined safety factor.
Means for detecting the actual slip amount of the clutch;
The safety factor, the previous SL actual slip amount is large nearly as Ru set Teisu to a smaller value correcting means of the clutch
Control device for varying the speed you characterized in that it comprises.

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