JP2006046515A - Hydraulic controller of automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress vibration and noise from the oil pump of an automatic transmission at extremely low temperatures. <P>SOLUTION: An ECU performs a program comprising a step S100 for detecting a shift position, a step S120 for determining whether forward/backward movement clutches are disengaged or not when a shift lever is moved to "P" position or "N" position (YES in S110), and a step (S150) determining a line pressure set value at a value for low oil temperature and reducing a line pressure when the forward/backward movement clutches are disengaged (YES in S120) and an oil temperature T (C) is lower than an oil temperature threshold T (TH) set to an extremely low temperature. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to hydraulic control of an automatic transmission, and more particularly to a technique for adjusting a line pressure according to the oil temperature of hydraulic oil.

  An automatic transmission mounted on a vehicle is generally composed of a torque converter and a transmission mechanism. Examples of the transmission mechanism include a stepped transmission mechanism such as a planetary gear type and a continuously variable transmission mechanism such as a belt type. The torque converter is usually composed of three types of impellers, that is, a pump, a turbine, and a stator, and transmits engine power to an output shaft through an internal fluid to perform continuous torque conversion in accordance with deceleration.

  The planetary gear type speed change mechanism is composed of a sun gear, a pinion that meshes with the sun gear, a planet carrier that supports the pinion, a ring gear, and the like. Provided. The belt-type continuously variable transmission mechanism connects the primary pulley and the secondary pulley with a metal belt, and changes the width of these pulleys to change the speed steplessly.

  In any of these transmission mechanisms, the shift position selected by the driver (the “P” position for parking, the “R” position for reverse travel, the “N” position for cutting off power transmission, the “ Depending on the “D” position, “L” position, etc.), a friction engagement element, which is a specific clutch or brake, is provided for transmitting / not transmitting power by engagement / release. In order to control these friction engagement elements, a hydraulic control device including an oil pump, a pressure regulating valve, a pressure reducing valve, and the like is used. In this hydraulic control device, the hydraulic pressure of the friction engagement element is realized by duty control of the solenoid valve. Japanese Laid-Open Patent Publication No. 1-307552 (Patent Document 1) discloses a hydraulic control device for an automatic transmission that solves the problem that sufficient responsiveness cannot be ensured due to the fact that when the oil temperature is low, the viscosity becomes high and the response delay of the hydraulic oil occurs. Is disclosed.

  This hydraulic control device is a hydraulic control device for an automatic transmission that duty-controls the pilot pressure of the adjustment valve using the original pressure obtained by reducing the discharge pressure of the oil pump to a constant pressure by a pressure reducing valve. The pressure level of the original pressure obtained through the pressure reducing valve is provided according to the oil temperature so that the lower the oil temperature, the higher the pressure level can be selected.

According to this hydraulic control device, the discharge pressure of the oil pump is reduced to a constant pressure by a pressure reducing valve, and the hydraulic pressure adjusting valve is operated by so-called duty control that adjusts the opening / closing time ratio of the oil drainage hole using the constant pressure of the hydraulic pressure as the original pressure. The pilot pressure is controlled. The pressure level of the original pressure obtained by the pressure reducing valve is selectively switched according to the oil temperature. Therefore, by using a high level of the original pressure when the oil temperature is low and by using a normal level of the original pressure when the oil temperature is higher than a predetermined value, the difference in response due to the difference in viscosity is corrected. Therefore, accurate hydraulic characteristics can always be obtained.
JP-A-1-307552

  However, in the hydraulic control device disclosed in Patent Document 1, the oil pressure is low and the viscosity is high when the clutch is engaged by increasing the line pressure that is the original pressure at low oil temperature. This suppresses the response delay of the hydraulic pressure. For this reason, since the line pressure is increased, if the load of the oil pump increases, the viscosity of the hydraulic oil increases, and thus the hydraulic oil may not be discharged stably. In such a case, vibration or noise is generated.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an automatic transmission that can suppress vibration and noise of an oil pump generated when hydraulic oil of the automatic transmission is at a low temperature. It is to provide a hydraulic control device.

  A hydraulic control apparatus according to a first aspect of the present invention controls the hydraulic pressure of an automatic transmission connected to a power source. The hydraulic control device includes temperature detecting means for detecting the temperature of hydraulic oil of the automatic transmission, and detecting means for detecting that a friction engagement element to which hydraulic oil is not supplied when the vehicle is stopped is released. The hydraulic pressure output from the hydraulic device that adjusts the hydraulic pressure of the hydraulic fluid supplied from the oil pump of the automatic transmission when the hydraulic fluid temperature is lower than a predetermined temperature and the friction engagement element is released. Control means for controlling the hydraulic equipment so that the hydraulic pressure does not exceed a predetermined hydraulic pressure.

  According to the first invention, when the temperature of the hydraulic oil of the automatic transmission is low, the viscosity is high, and the hydraulic equipment that adjusts the hydraulic pressure of the hydraulic oil discharged from the oil pump to the line pressure is set to a high line pressure. If this happens, vibration and noise will occur in the oil pump. This becomes significant when the viscosity is high. For this reason, when the temperature of the hydraulic oil is low and the control means does not need to engage the friction engagement element that is engaged when the vehicle travels, the hydraulic pressure output from the hydraulic device exceeds the predetermined hydraulic pressure. Control the hydraulic equipment so that it does not occur. In this way, when it is not necessary to supply a high hydraulic pressure to the friction engagement element that is engaged during vehicle travel (forward, reverse), it is possible to suppress the occurrence of vibration and noise by the oil pump. As a result, it is possible to provide a hydraulic control device for an automatic transmission that can suppress the vibration and noise of the oil pump generated when the hydraulic oil of the automatic transmission is at a low temperature.

  In the hydraulic control apparatus according to the second invention, in addition to the configuration of the first invention, the detecting means detects that the friction engagement element is released when the shift position is in the neutral position or the parking position. Means for.

  According to the second aspect of the present invention, it is not necessary to increase the line pressure when the vehicle is in a neutral state or a parking state. Therefore, in such a case, the upper limit guard is set so that the line pressure does not increase, And noise can be suppressed.

  In the hydraulic control device according to the third aspect of the invention, in addition to the configuration of the first aspect of the invention, the detecting means releases the friction engagement element when the engagement command signal to the friction engagement element is not output. Means for detecting that the

  According to the third invention, when the friction engagement element to which hydraulic oil is not supplied when the vehicle is stopped is released, it is not necessary to increase the line pressure. In such a case, the upper limit guard is set so that the line pressure does not increase. Thus, vibration and noise of the oil pump can be suppressed.

  In the hydraulic control device according to the fourth aspect of the invention, in addition to the configuration of the first aspect of the invention, the detecting means outputs the engagement command signal to the friction engagement element when the shift position is the neutral position or the parking position. If not, it includes means for detecting that the frictional engagement element is released.

  According to the fourth aspect of the present invention, when the vehicle is in a neutral state or a parking state, and the friction engagement element to which hydraulic oil is not supplied when the vehicle is stopped is released, it is not necessary to increase the line pressure. In such a case, the upper limit guard can be set so that the line pressure does not increase, and the vibration and noise of the oil pump can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  A vehicle equipped with a control device according to the present embodiment will be described with reference to FIG. The output of the engine 200 of the drive device 100 mounted on the vehicle is input to the belt type continuously variable transmission 500 via the torque converter 300 and the forward / reverse switching device 400. The output of the belt type continuously variable transmission 500 is transmitted to the reduction gear 600 and the differential gear device 700 and distributed to the left and right drive wheels 800. The driving device 100 is controlled by an ECU (Electronic Control Unit) 900 described later. The control device according to the present embodiment is realized by a program executed by ECU 900, for example. The control device according to the present embodiment is not limited to such a belt-type continuously variable transmission, but can be applied to an automatic transmission having a stepped transmission mechanism. Further, the drive source of the vehicle is not limited to the engine, and may be an engine, a motor, and a motor.

  The torque converter 300 includes a pump impeller 302 connected to the crankshaft of the engine 200 and a turbine impeller 306 connected to the forward / reverse switching device 400 via the turbine shaft 304. A lockup clutch 308 is provided between the pump impeller 302 and the turbine impeller 306. The lockup clutch 308 is engaged or released when the hydraulic pressure supply to the engagement side oil chamber and the release side oil chamber is switched.

  When the lockup clutch 308 is completely engaged, the pump impeller 302 and the turbine impeller 306 are integrally rotated. The pump impeller 302 includes a mechanical oil pump 310 that generates a hydraulic pressure for controlling the shift of the belt type continuously variable transmission 500, generating a belt clamping pressure, and supplying lubricating oil to each part. Is provided.

  The forward / reverse switching device 400 is composed of a double pinion type planetary gear device. Turbine shaft 304 of torque converter 300 is connected to sun gear 402. The input shaft 502 of the belt type continuously variable transmission 500 is connected to the carrier 404. Carrier 404 and sun gear 402 are connected via forward clutch 406. Ring gear 408 is fixed to the housing via reverse brake 410. The forward clutch 406 and the reverse brake 410 are frictionally engaged by a hydraulic cylinder.

  When the forward clutch 406 is engaged and the reverse brake 410 is released, the forward / reverse switching device 400 enters the forward connection state. In this state, the driving force in the forward direction is transmitted to the belt type continuously variable transmission 500. When the reverse brake 410 is engaged and the forward clutch 406 is released, the forward / reverse switching device 400 enters the reverse connection state. In this state, the input shaft 502 is rotated in the reverse direction with respect to the turbine shaft 304. As a result, the driving force in the reverse direction is transmitted to the belt type continuously variable transmission 500. When both forward clutch 406 and reverse brake 410 are released, forward / reverse switching device 400 enters a neutral state in which power transmission is interrupted.

  The belt type continuously variable transmission 500 includes a primary pulley 504 provided on the input shaft 502, a secondary pulley 508 provided on the output shaft 506, and a transmission belt 510 wound around these pulleys. Power is transmitted using frictional forces between the pulleys and the transmission belt 510.

  Each pulley is composed of a hydraulic cylinder so that the groove width is variable. By controlling the hydraulic pressure of the hydraulic cylinder of the primary pulley 504, the groove width of each pulley changes. As a result, the engagement diameter of the transmission belt 510 is changed, and the gear ratio GR (= primary pulley rotation speed NIN / secondary pulley rotation speed NOUT) is continuously changed.

  As shown in FIG. 2, the ECU 900 includes an engine speed sensor 902, a turbine speed sensor 904, a vehicle speed sensor 906, a throttle sensor 908, a coolant temperature sensor 910, an oil temperature sensor 912, an accelerator opening sensor 914, and a foot brake switch. 916, a position sensor 918, a primary pulley rotation speed sensor 922, and a secondary pulley rotation speed sensor 924 are connected.

  The engine speed sensor 902 detects the engine speed (engine speed) NE of the engine 200. The turbine rotation speed sensor 904 detects the rotation speed (turbine rotation speed) NT of the turbine shaft 304. The vehicle speed sensor 906 detects the vehicle speed V. The throttle opening sensor 908 detects the opening degree θ (TH) of the electronic throttle valve. Cooling water temperature sensor 910 detects cooling water temperature T (W) of engine 200. The oil temperature sensor 912 detects the oil temperature T (C) of the belt type continuously variable transmission 500 or the like. The accelerator opening sensor 914 detects the accelerator pedal opening A (CC). The foot brake switch 916 detects whether or not the foot brake is operated. The position sensor 918 detects the position P (SH) of the shift lever 920. Primary pulley rotation speed sensor 922 detects the rotation speed NIN of primary pulley 504. Secondary pulley rotation speed sensor 924 detects rotation speed NOUT of secondary pulley 508. A signal representing the detection result of each sensor is transmitted to ECU 900. The turbine rotational speed NT coincides with the primary pulley rotational speed NIN during forward traveling with the forward clutch 406 engaged. The vehicle speed V becomes a value corresponding to the secondary pulley rotation speed NOUT.

ECU 900 includes a CPU (Central Processing Unit), a memory, an input / output interface, and the like. The CPU performs signal processing according to a program stored in the memory. Thereby, output control of the engine 200, shift control of the belt-type continuously variable transmission 500, belt clamping pressure control, engagement / release control of the forward clutch 406, engagement / release control of the reverse brake 410, and the like are executed.

  Output control of the engine 200 is performed by an electronic throttle valve 1000, a fuel injection device 1100, an ignition device 1200, and the like. The hydraulic control circuit 1300 performs shift control of the belt-type continuously variable transmission 500, belt clamping pressure control, engagement / release control of the forward clutch 406, and engagement / release control of the reverse brake 410.

  With reference to FIG. 3, a part of the hydraulic control circuit related to the present embodiment in the hydraulic control circuit 1300 will be described. The hydraulic control circuit 1300 includes an oil pump 1310, a primary regulator valve 1320, a linear solenoid valve (SLS) 1330, a clutch control valve 1340, a clutch apply control valve 1350, a line pressure modulator valve 1360, and a manual valve 1370.

  The oil pump 1310 is operated by the rotation of the engine to generate a predetermined oil pressure (oil pump discharge pressure), and the oil pressure is a signal from the ECU 900 that is calculated based on the pulley ratio and the throttle opening (ie, input torque). The primary regulator valve 1320 is controlled based on the SLS (control) pressure from the linear solenoid valve (SLS) 1330 controlled by the pressure, so that the line pressure PL is regulated. Further, the secondary pressure is regulated by the secondary regulator valve. Further, the signal oil pressure (SLS pressure) from the output port of the linear solenoid valve (SLS) 1330 is supplied to the control oil chamber of the secondary sheave control valve via the oil passage, and the line pressure is adjusted to the secondary sheave pressure PSS. Is then supplied to the secondary hydraulic actuator.

  Manual valve 1370 is mechanically switched according to the operation of shift lever 920. Thereby, the forward clutch 406 and the reverse brake 410 are engaged or released.

  The shift lever 920 is operated to the “P” position for parking, the “R” position for reverse travel, the “N” position for interrupting power transmission, the “D” position and “L” position for forward travel.

  In the “P” position and the “N” position, the hydraulic pressure in the forward clutch 406 and the reverse brake 410 is drained from the manual valve 1370. Thereby, the forward clutch 406 and the reverse brake 410 are released.

  In the “R” position, hydraulic pressure is supplied from the manual valve 1370 to the reverse brake 410. Thereby, the reverse brake 410 is engaged. On the other hand, the hydraulic pressure in the forward clutch 406 is drained from the manual valve 1370, thereby releasing the forward clutch 406.

  In the “D” position and the “L” position, the hydraulic pressure is supplied from the manual valve 1370 to the forward clutch 406. As a result, the forward clutch 406 is engaged. On the other hand, the hydraulic pressure in the reverse brake 410 is drained from the manual valve 120. Thereby, the reverse brake 410 is released.

  When hydraulic pressure is supplied to forward clutch 406 and reverse brake 410, clutch control valve 1340, clutch apply control valve 1350, and line pressure modulator valve 1360 are operated to generate a desired clutch pressure.

  Thus, the line pressure PL, which is the oil pressure on the discharge side of the oil pump 1310, is regulated to the line pressure PL by controlling the primary regulator valve 1320 based on the SLS (control) pressure output from the ECU 900. . At this time, in order to engage the forward clutch 406 and the reverse brake 410 with high responsiveness, the line pressure PL is preferably set to a desired high hydraulic pressure. If the line pressure PL, which is the oil pressure on the discharge side of the oil pump 1310, is set to be high, due to the hardware characteristics of the oil pump 1310, if hydraulic oil (oil) is discharged at a certain oil pressure or higher, Vibration and noise are generated. This is more remarkable when the oil temperature is low and the oil viscosity is high. The ECU 900 as the control device according to the present embodiment is characterized in that such vibration and noise are not generated from the oil pump 1310 when the forward clutch 406 and the reverse brake 410 need not be engaged. Execute control.

  With reference to FIG. 4, a control structure of a program executed by ECU 900 which is the control apparatus according to the present embodiment will be described.

  In step (hereinafter step is abbreviated as S) 100, ECU 900 detects the shift position. At this time, the shift position is detected based on the position P (SH) input from the position sensor 918 input to the ECU 900. In S110, ECU 900 determines whether the position is the “P” position or the “N” position. If the shift position is the “P” position or the “N” position (YES in S110), the process proceeds to S120. If not (NO in S110), the process proceeds to S160.

  In S120, ECU 900 determines whether or not the forward / reverse clutch is in a released state. This is because the forward / reverse clutch release determination flag is on because the engagement command signals to the forward clutch 406 and the reverse brake 410 are off, and the forward / reverse clutch is determined to be in the released state. If the forward / reverse clutch is in the released state (YES in S120), the process proceeds to S130. If not (NO in S120), the process proceeds to S160.

  In S130, the engine ECU detects the oil temperature T (C). At this time, ECU 900 detects oil temperature T (C) based on a signal representing oil temperature T (C) input from CVT oil temperature sensor 912.

  In S140, ECU 900 determines whether or not detected oil temperature T (C) is lower than a predetermined oil temperature threshold value T (TH). The oil temperature threshold value T (TH) is set to an extremely low temperature, for example. If oil temperature T (C) is lower than a predetermined oil temperature threshold value T (TH) (YES in S140), the process proceeds to S150. If not (NO in S140), the process proceeds to S160.

  In S150, ECU 900 determines the line pressure set value for the low oil temperature. At this time, the ECU 900 sets the control duty for the linear solenoid valve 1330 (SLS) of the hydraulic control circuit 1300 to be high so that the line pressure becomes low. In S160, ECU 900 determines the line pressure set value for normal use. At this time, the ECU 900 sets the control duty for the linear solenoid valve 1330 (SLS) of the hydraulic circuit 1300 to be low so that the line pressure becomes high.

  An operation of the automatic transmission of the vehicle equipped with the control device according to the present embodiment based on the above-described structure and flowchart will be described.

  If the vehicle is stopped and the shift position is the “P” position or the “N” position (YES in S110), whether or not the forward / reverse clutch (forward clutch 406 and reverse brake 410) is in the released state is determined. Determination is made (S120). If the forward / reverse clutch is disengaged (YES in S120), oil temperature T (C) is detected (S130), and oil temperature threshold T (TH) at which oil temperature T (C) is set to a very low temperature is detected. ) (YES in S140), the line pressure set value is determined for the low oil temperature (S150). When the line pressure set value is determined for the low oil temperature, ECU 900 increases the control duty output to linear solenoid valve 1330 (SLS), and linear solenoid valve 1330 (SLS) is primary so that the line pressure decreases. The regulator valve 1320 is controlled.

  By doing so, the line pressure adjusted by the primary regulator valve 1320 for adjusting the oil pressure of the oil discharged from the oil pump 1310 is set to be low, and the pressure when discharged from the oil pump 1310 is not increased. Therefore, due to the pulsation of the oil pump 1310, vibration and noise are not generated even when the viscosity of the oil is high. At this time, since the forward / reverse clutch is in a disengaged state, a high line pressure is not required to engage the forward / reverse clutch, so that there is no problem in the hydraulic circuit.

  As described above, according to the control device according to the present embodiment, when the position of the automatic transmission is the “P” position or the “N” position and the oil temperature is extremely low, the pressure is regulated by the primary regulator valve. The linear solenoid valve is controlled so that the line pressure is lowered. If it does in this way, it can control that oil pump's vibration and noise generate | occur | produce due to the viscosity of oil being high at low temperature.

  Note that the shift position is detected in S110 shown in FIG. 4 and it is determined whether the shift position is the “P” position or the “N” position. However, the present invention is not limited to this. You may make it detect that a contact and an N contact are in an ON state.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a skeleton figure of the vehicle carrying the control device concerning an embodiment of the invention. It is a control block diagram which shows the control apparatus which concerns on embodiment of this invention. It is a figure which shows the hydraulic control circuit controlled by the control apparatus which concerns on this Embodiment. It is a flowchart which shows the control structure of the program which ECU of the control apparatus which concerns on embodiment of this invention performs.

Explanation of symbols

  200 engine, 400 forward / reverse switching device, 402 sun gear, 404 carrier, 406 forward clutch, 408 ring gear, 410 reverse brake, 500 belt type continuously variable transmission, 504 primary pulley, 508 secondary pulley, 510 transmission belt, 900 ECU, 904 Turbine speed sensor, 920 shift lever, 922 primary pulley speed sensor, 924 secondary pulley speed sensor, 1000 electronic throttle valve, 1100 fuel injection device, 1200 ignition device, 1300 hydraulic control circuit, 1310 oil pump, 1320 primary regulator valve , 1330 Linear solenoid valve (SLS), 1340 Clutch control valve, 1350 Clutch apply control bar Breakfast, 1360 line pressure modulator valve, 1370 manual valve.

Claims (4)

A hydraulic control device for an automatic transmission connected to a power source,
Temperature detecting means for detecting the temperature of hydraulic oil of the automatic transmission;
Detecting means for detecting that a friction engagement element to which hydraulic oil is not supplied when the vehicle is stopped is released;
When the temperature of the hydraulic oil is lower than a predetermined temperature and the friction engagement element is released, the hydraulic oil is output from a hydraulic device that adjusts the hydraulic pressure of the hydraulic oil supplied from the oil pump of the automatic transmission. And a control means for controlling the hydraulic device such that the hydraulic pressure does not exceed a predetermined hydraulic pressure.   The hydraulic control device according to claim 1, wherein the detection means includes means for detecting that the friction engagement element is released when a shift position is a neutral position or a parking position.   2. The hydraulic control according to claim 1, wherein the detection means includes means for detecting that the friction engagement element is released when an engagement command signal to the friction engagement element is not output. 3. apparatus.   The detecting means detects that the friction engagement element is released when the shift position is a neutral position or a parking position and an engagement command signal to the friction engagement element is not output. The hydraulic control device according to claim 1, comprising means.

Images