Transmission, control method for transmission, and program

Abstract

The present application provides a kind of transmission that can further reduce the excess amount of main pressure, the control method and program of transmission.The transmission is equipped with: primary pulley, secondary pulley, belt, oil pressure control circuit that regulates the oil supplied from oil pump to main pressure, main pressure detection sensor that detects main pressure, transmission controller that controls oil pressure control circuit.And, transmission controller selects the higher one of the target value of primary pulley pressure and the target value of secondary pulley pressure as target pulley pressure, sets target pressure difference variably according to oil temperature, sets the target value of main pressure, i.e.target main pressure, as the total pressure of target pulley pressure and target pressure difference, controls oil pressure control circuit so that the detected main pressure is regulated to target main pressure.

Description

Technical Field

[0001] This invention relates to a transmission, a control method for the transmission, and a program for the transmission. Background Technology

[0002] Patent document 1 discloses a transmission that suppresses oil pressure deviation and reduces excess main pressure (line pressure) by setting a main pressure sensor.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2006-097811

[0006] The problem that the invention aims to solve

[0007] However, due to the low detection accuracy of the main pressure sensor, it cannot fully reduce the excess amount of main pressure. Summary of the Invention

[0008] The present invention was made in view of such a problem, and its object is to provide a transmission, a control method and program for the transmission that can further reduce the excess amount of main pressure.

[0009] According to one aspect of the present invention, a transmission is provided, comprising: a primary pulley; a secondary pulley; a transmission member wound around the primary pulley and the secondary pulley; an oil pump for supplying oil; an oil pressure control circuit for adjusting the pressure of the oil supplied by the oil pump to an initial pressure, i.e., a main pressure (line pressure), for supplying a primary pulley pressure to the primary pulley and a secondary pulley pressure to the secondary pulley; a main pressure detection unit for detecting the main pressure; and a controller for controlling the oil pressure control circuit, wherein the controller selects the higher of a target value of the primary pulley pressure and a target value of the secondary pulley pressure as a target pulley pressure, variably sets a target pressure difference based on oil temperature, sets the target value of the main pressure, i.e., the target main pressure, to the sum of the target pulley pressure and the target pressure difference, and controls the oil pressure control circuit to adjust the detected main pressure to the target main pressure.

[0010] According to another aspect of the present invention, a control method for a transmission is provided, the transmission comprising: a primary pulley; a secondary pulley; a transmission component wound around the primary pulley and the secondary pulley; an oil pump for supplying oil; and an oil pressure control circuit for adjusting the pressure of oil supplied by the oil pump to an initial pressure, i.e., a main pressure, for supplying a primary pulley pressure to the primary pulley and a secondary pulley pressure to the secondary pulley, wherein the control method for the transmission includes: a main pressure detection step for detecting the main pressure; selecting the higher of a target value of the primary pulley pressure and a target value of the secondary pulley pressure as a target pulley pressure, variably setting a target pressure difference based on oil temperature, setting the target value of the main pressure, i.e., the target main pressure, to the sum of the target pulley pressure and the target pressure difference, and controlling the oil pressure control circuit to adjust the detected main pressure to the target main pressure.

[0011] According to another aspect of the present invention, a program is provided that is a computer-executable program for controlling a transmission, the transmission comprising: a primary pulley; a secondary pulley; a transmission component wound around the primary pulley and the secondary pulley; an oil pump for supplying oil; and an oil pressure control circuit for adjusting the pressure of the oil supplied by the oil pump to an initial pressure, i.e., a main pressure, for supplying a primary pulley pressure to the primary pulley and a secondary pulley pressure to the secondary pulley, wherein the program causes the computer to perform the following steps: a main pressure detection step for detecting the main pressure; selecting the higher of a target value of the primary pulley pressure and a target value of the secondary pulley pressure as a target pulley pressure, variably setting a target pressure difference based on oil temperature, setting the target value of the main pressure, i.e., the target main pressure, to the sum of the target pulley pressure and the target pressure difference, and controlling the oil pressure control circuit to adjust the detected main pressure to the target main pressure.

[0012] Invention Effects

[0013] These methods can further reduce the excess amount of main pressure. Attached Figure Description

[0014] Figure 1 It is a schematic diagram of the vehicle's structure.

[0015] Figure 2 This is a schematic diagram of the hydraulic control circuit.

[0016] Figure 3 This is a block diagram showing the transmission controller and the main structures connected to it.

[0017] Figure 4 This is a flowchart illustrating the control processing of the hydraulic control circuit.

[0018] Figure 5 It is a chart used to set the target belt wheel pressure.

[0019] Figure 6 This is an explanatory diagram used to illustrate the target pressure difference.

[0020] Figure 7 It is a chart used to set the target differential pressure. Detailed Implementation

[0021] Hereinafter, embodiments of the present invention (hereinafter referred to as "this embodiment") will be described with reference to the accompanying drawings.

[0022] (Structure of the transmission)

[0023] First, refer to Figure 1 The transmission TM of this embodiment is described.

[0024] Figure 1 It is a schematic diagram of the vehicle's structure.

[0025] like Figure 1 As shown, the vehicle includes: an engine ENG, a hydraulic torque converter TC, a forward / reverse switching mechanism SWM, and a transmission mechanism VA. In the vehicle, the transmission TM, which serves as the working machinery, is a belt-type continuously variable transmission (CVT) with a hydraulic torque converter TC, a forward / reverse switching mechanism SWM, and a transmission mechanism VA.

[0026] The engine (ENG) constitutes the drive source of the vehicle. The power from the engine (ENG) is transmitted to the drive wheels (DW) via the torque converter (TC), the forward / reverse switching mechanism (SWM), and the transmission mechanism (VA). In other words, the torque converter (TC), the forward / reverse switching mechanism (SWM), and the transmission mechanism (VA) are located on the power transmission path connecting the engine (ENG) and the drive wheels (DW).

[0027] The torque converter TC transmits power via fluid. Within the torque converter TC, a lock-up clutch LU is used to improve power transmission efficiency.

[0028] The forward / reverse switching mechanism (SWM) is located on the power transmission path connecting the engine (ENG) and the transmission mechanism (VA). The SWM switches between forward and reverse gears by changing the direction of the input rotation. The SWM includes a forward clutch (FWD / C) that engages when forward gear is selected and a reverse brake (REV / B) that engages when reverse gear is selected. When the forward clutch (FWD / C) and the reverse brake (REV / B) are released, the transmission (TM) is in neutral, i.e., power is cut off.

[0029] The transmission mechanism VA constitutes a belt-type continuously variable transmission (CVT) having a primary pulley PRI, a secondary pulley SEC, and a belt BLT wound around the primary pulley PRI and the secondary pulley SEC as transmission components. Hydraulic control circuit 1 (described later) supplies hydraulic pressure (Ppri) to the primary pulley PRI and hydraulic pressure (Psec) to the secondary pulley SEC.

[0030] The transmission™ is configured to also include: a mechanical oil pump MP, an electric oil pump EP, and an electric motor M.

[0031] The mechanical oil pump MP supplies oil to the oil pressure control circuit 1. A check valve 25 is installed in the flow path connecting the mechanical oil pump MP and the oil pressure control circuit 1. The mechanical oil pump MP is driven by the engine ENG.

[0032] The electric oil pump EP, together with or separately from the mechanical oil pump MP, pumps oil into the hydraulic control circuit 1. A check valve 26 is provided in the flow path connecting the electric oil pump EP and the hydraulic control circuit 1. The electric oil pump EP is provided as an auxiliary component relative to the mechanical oil pump MP. The electric motor M drives the electric oil pump EP. The electric oil pump EP can also be understood as being configured with an electric motor M.

[0033] The transmission TM is configured to also include a hydraulic control circuit 1 and a transmission controller 2. The hydraulic control circuit 1 consists of multiple flow paths and multiple hydraulic control valves, which regulate the pressure of the oil supplied from the mechanical oil pump MP or the electric oil pump EP and supply it to various parts of the transmission TM.

[0034] The transmission controller 2 is a controller for controlling the transmission TM, based on various sensors (specifically, including: primary pulley pressure sensor 27, secondary pulley pressure sensor 28, main pressure sensor 29, and oil temperature sensor 30). (See reference...) Figure 2 and Figure 3 The signals output by the transmission controller 2 control the motor M of the drive hydraulic control circuit 1 and the electric oil pump EP. In this embodiment, the transmission controller 2 is composed of a CPU, which is a computer, but it is not limited to this; for example, it may be composed of multiple microcomputers. Further details regarding the transmission controller 2 will be described later.

[0035] Hydraulic control circuit 1 performs hydraulic control of the lock-up clutch LU, forward clutch FWD / C, reverse brake REV / B, primary pulley PRI, secondary pulley SEC, etc., based on instructions from transmission controller 2.

[0036] (Structure of the hydraulic control circuit)

[0037] Next, refer to Figure 2 The hydraulic control circuit 1 is described below.

[0038] Figure 2 This is a schematic diagram of the hydraulic control circuit 1.

[0039] like Figure 2 As shown, the hydraulic control circuit 1 includes: a pressure regulating valve 11, a primary regulating valve 12, a secondary regulating valve 13, a clutch regulating valve 14, a torque converter regulating valve 15, a lock-up regulating valve 16, a first pilot valve 17, a main pressure (pipeline pressure) solenoid valve 18, a primary solenoid valve 19, a secondary solenoid valve 20, a clutch pressure solenoid valve 21, a second pilot valve 22, a lock-up solenoid valve 23, and a third pilot valve 24.

[0040] Pressure regulating valve 11 adjusts the discharge oil from at least one of the mechanical oil pump MP and the electric oil pump EP to the main pressure (pipeline pressure) PL. Furthermore, the main pressure PL is the initial pressure of the pulley pressure, described later. The dashed line indicating the main pressure PL does not represent the oil passage, but rather the oil pressure. Pressure regulating valve 11 regulates the pressure while discharging a portion of the oil discharged from the oil pump. The oil regulated to the main pressure PL is supplied to the primary regulating valve 12, the secondary regulating valve 13, and the first pilot valve 17.

[0041] Primary regulating valve 12 and secondary regulating valve 13 are pulley pressure control valves, which control the pulley pressure by adjusting the pressure of the oil to be regulated as the main pressure PL to the pulley pressure. The pulley pressure is the primary pulley pressure Ppri when the primary regulating valve 12 is used, and the pulley pressure is the secondary pulley pressure Psec when the secondary regulating valve 13 is used.

[0042] Oil discharged from pressure regulating valve 11 is supplied to clutch regulating valve 14. Clutch regulating valve 14 regulates the oil discharged from pressure regulating valve 11 to clutch pressure. The oil pressure regulated to clutch pressure is selectively supplied to either the forward clutch FWD / C or the reverse brake REV / B. Clutch regulating valve 14 regulates pressure while discharging a portion of the oil.

[0043] Oil discharged from clutch regulating valve 14 is supplied to torque converter regulating valve 15. Torque converter regulating valve 15 regulates the oil discharged from pressure regulating valve 11 to the torque converter pressure of hydraulic torque converter TC. While discharging a portion of the oil, torque converter regulating valve 15 regulates the pressure, and the discharged oil is supplied to the lubrication system of transmission TM. The oil pressure regulated to torque converter pressure is supplied to hydraulic torque converter TC and lock-up regulating valve 16.

[0044] The lock-up regulating valve 16 adjusts the oil, which is regulated to the torque converter pressure, to the lock-up pressure. The lock-up clutch LU is locked by the lock-up pressure difference, which is the pressure difference between the torque converter pressure and the lock-up pressure. The oil, regulated to the lock-up pressure, is supplied to the lock-up clutch LU.

[0045] Pressure regulating valve 11 regulates pressure based on the signal pressure generated by main pressure solenoid valve 18. The same applies to primary regulating valve 12 and primary solenoid valve 19, secondary regulating valve 13 and secondary solenoid valve 20, clutch regulating valve 14 and clutch pressure solenoid valve 21, and lock-up regulating valve 16 and lock-up solenoid valve 23.

[0046] A first pilot pressure P1 is introduced as an initial pressure into the main pressure solenoid valve 18, the primary solenoid valve 19, the secondary solenoid valve 20, and the clutch pressure solenoid valve 21, respectively. The first pilot pressure P1 is generated by the first pilot valve 17 with the main pressure PL as the initial pressure. The first pilot pressure P1 is also introduced into the second pilot valve 22.

[0047] The second pilot valve 22 uses the first pilot pressure P1 as the initial pressure to generate the second pilot pressure P2. The second pilot pressure P2 is set above the lower limit of the set range of the main pressure PL. The second pilot pressure P2 is preset considering the controllability of the lock-up clutch LU. The second pilot pressure P2 is introduced into the lock-up solenoid valve 23 and the third pilot valve 24.

[0048] The lock-up solenoid valve 23 uses the second pilot pressure P2 as the initial pressure to generate a lock-up signal pressure. The lock-up signal pressure is a signal pressure generated by the lock-up solenoid valve 23 to control the lock-up pressure of the lock-up clutch LU of the torque converter TC.

[0049] The third pilot valve 24 uses the second pilot pressure P2 as the initial pressure to generate the third pilot pressure P3. The third pilot pressure P3 is set to be lower than the lower limit of the main pressure PL. The third pilot pressure P3 is preset considering the damping properties of the primary control valve 12 and the secondary control valve 13. The third pilot pressure P3 is introduced into the primary control valve 12 and the secondary control valve 13 as a damping pressure.

[0050] The third pilot pressure P3, acting as the damping pressure, is introduced into the primary regulating valve 12 in a manner opposite to the primary signal pressure. The primary signal pressure is the signal pressure generated by the primary solenoid valve 19 to control the primary pulley pressure Ppri.

[0051] Similarly, the third pilot pressure P3, which is introduced as the damping pressure, is introduced into the secondary regulating valve 13 in a manner opposite to the secondary signal pressure. The secondary signal pressure is the signal pressure generated by the secondary solenoid valve 20 to control the secondary pulley pressure Psec.

[0052] In addition, the hydraulic control circuit 1 is equipped with: a primary pulley pressure detection sensor 27, which serves as a primary pulley pressure detection unit for detecting the primary pulley pressure Ppri of the primary pulley PRI; a secondary pulley pressure detection sensor 28, which serves as a secondary pulley pressure detection unit for detecting the secondary pulley pressure Psec of the secondary pulley SEC; a main pressure detection sensor 29, which serves as a main pressure detection unit for detecting the main pressure PL; and an oil temperature detection sensor 30, which serves as an oil temperature detection unit for detecting the oil temperature T of the oil supplied from the mechanical oil pump MP or the electric oil pump EP.

[0053] (Structure of the transmission controller)

[0054] Next, refer to Figure 3 The transmission controller 2 will be described.

[0055] Figure 3 This is a block diagram showing the transmission controller 2 and the main structures connected to the transmission controller 2.

[0056] like Figure 3 As shown, the transmission controller 2 includes: an input interface 31, an output interface 32, a storage device 33, a motor control device 34, and a hydraulic control loop control device 35 (hereinafter referred to as the loop control device 35) that are electrically connected to each other.

[0057] The input interface 31 receives the output signals from the primary pulley pressure sensor 27 (which detects the primary pulley pressure Ppri supplied to the primary pulley PRI), the secondary pulley pressure sensor 28 (which detects the secondary pulley pressure Psec supplied to the secondary pulley SEC), the main pressure sensor 29 (which detects the main pressure PL), and the oil temperature sensor 30 (which detects the oil temperature T supplied from the mechanical oil pump MP or the electric oil pump EP).

[0058] The motor control command generated by the motor control device 34 and the loop control command generated by the loop control device 35 are output to the motor M and the hydraulic control loop 1 respectively via the output interface 32.

[0059] Storage device 33 is a memory used to temporarily store parameters contained in the output signals from various sensors (primary pulley pressure detection sensor 27, secondary pulley pressure detection sensor 28, main pressure detection sensor 29, and oil temperature detection sensor 30). In addition, storage device 33 stores pulley pressure setting charts and target differential pressure setting charts, which will be described later.

[0060] Furthermore, the storage device 33 stores the processing program and algorithm program executed in the motor control device 34 and the loop control device 35. In this embodiment, the storage device 33 is built into the transmission controller 2, but it is not limited thereto; for example, it may be set separately from the transmission controller 2.

[0061] The motor control device 34 generates motor control commands based on output signals from various sensors, etc., and outputs the generated motor control commands to the motor M via the output interface 32.

[0062] The loop control device 35 generates loop control commands based on output signals from various sensors, etc., and outputs the generated loop control commands to the hydraulic control loop 1 via the output interface 32.

[0063] Furthermore, the loop control device 35 includes: a target pulley pressure setting module 351 as a target pulley pressure setting unit; a target pulley pressure selection module 352 as a target pulley pressure selection unit; a target differential pressure setting module 353 as a target differential pressure setting unit; a target main pressure setting module 354 as a target main pressure setting unit; and a loop control command generation module 355 as a loop control command generation unit. Details regarding the target pulley pressure setting module 351, the target pulley pressure selection module 352, the target differential pressure setting module 353, the target main pressure setting module 354, and the loop control command generation module 355 will be described later in the control processing of the hydraulic control loop 1.

[0064] (Control processing of the hydraulic control circuit)

[0065] Next, refer to Figures 4 to 7 The control processing of hydraulic control circuit 1 (control processing of transmission™) is explained.

[0066] Figure 4 This is a flowchart representing the control processing of hydraulic control loop 1. Figure 5 It is a chart used to set the target belt wheel pressure. Figure 6 This is an explanatory diagram used to illustrate the target pressure difference ΔP. Figure 7 It is a graph used to set the target pressure difference ΔP, and it is a chart that shows the change of the target pressure difference ΔP caused by the oil temperature range.

[0067] like Figure 4 As shown, firstly, in step S1, various sensors detect various parameters. Specifically, the primary pulley pressure sensor 27, the secondary pulley pressure sensor 28, the main pressure sensor 29, and the oil temperature sensor 30 respectively detect the primary pulley pressure Ppri, the secondary pulley pressure Psec, the main pressure PL, and the oil temperature T.

[0068] Then, the primary pulley pressure sensor 27, secondary pulley pressure sensor 28, main pressure sensor 29, and oil temperature sensor 30 output the detected primary pulley pressure Ppri, secondary pulley pressure Psec, main pressure PL, and oil temperature T to the input interface 31 of the transmission controller 2. Then, the input interface 31 outputs the oil temperature T to the target differential pressure setting module 353, and outputs the primary pulley pressure Ppri, secondary pulley pressure Psec, and main pressure PL to the loop control command generation module 355, proceeding to step S2.

[0069] Next, in step S2, the target pulley pressure setting module 351 of the loop control device 35 sets the target primary pulley pressure tPpri as the target value of the primary pulley pressure Ppri and the target secondary pulley pressure tPsec as the target value of the secondary pulley pressure Psec based on the gear ratio of the transmission TM.

[0070] Specifically, in step S2, the target pulley pressure setting module 351 sets the pulley pressure based on the gear ratio of the transmission TM and the pulley pressure setting chart stored in the storage device 33 (see reference). Figure 5 The target primary pulley pressure tPpri and the target secondary pulley pressure tPsec are set. Then, the target pulley pressure setting module 351 outputs the set target primary pulley pressure tPpri and target secondary pulley pressure tPsec to the target pulley pressure selection module 352 and the loop control command generation module 355, and proceeds to step S3.

[0071] Next, in step S3, the target pulley pressure selection module 352 selects the higher of the target primary pulley pressure tPpri and the target secondary pulley pressure tPsec output from the target pulley pressure setting module 351 as the target pulley pressure tPP. Then, the target pulley pressure selection module 352 outputs the selected target pulley pressure tPP to the target main pressure setting module 354 and proceeds to step S4.

[0072] Next, in step S4, the target differential pressure setting module 353 variably sets the target differential pressure ΔP based on the oil temperature T output from the input interface 31. Therefore, the target differential pressure ΔP used for setting the target main pressure tPL (described later) is variably set according to the oil temperature T, thus further reducing the excess of the target main pressure tPL caused by the target differential pressure ΔP compared to the case where the target differential pressure ΔP is a fixed value. Then, the target differential pressure setting module 353 outputs the set target differential pressure ΔP to the target main pressure setting module 354, proceeding to step S5.

[0073] Here, as Figure 6As shown, the target pressure difference ΔP is the target pressure difference between the target pulley pressure tPP and the target main pressure tPL. It is composed of the detection deviation of the pulley pressure detection sensor (specifically, the primary pulley pressure detection sensor 27 or the secondary pulley pressure detection sensor 28), the necessary target pressure difference to suppress oil vibration, and the detection deviation of the main pressure detection sensor 29. In particular, the detection deviation of the main pressure detection sensor 29 has a significant impact on the setting of the target main pressure tPL.

[0074] The inventors discovered that the detection deviation (i.e., detection accuracy) of the main pressure detection sensor 29 varies depending on the oil temperature T.

[0075] Therefore, in step S4, the target differential pressure setting module 353 sets the target differential pressure setting chart (see reference) based on the oil temperature T and the target differential pressure setting chart stored in the storage device 33. Figure 7 The target differential pressure ΔP is set to vary depending on the oil temperature range. Therefore, the target differential pressure ΔP used to set the target main pressure tPL can be variably set according to the oil temperature range. Thus, compared to the case where the target differential pressure ΔP is a fixed value, the excess amount of target main pressure tPL caused by the target differential pressure ΔP can be further reduced.

[0076] Specifically, in step S4, the target differential pressure setting module 353 sets the target differential pressure ΔP to be larger than that in a second oil temperature region where the detection deviation of the main pressure detection sensor 29 is smaller than that in the first oil temperature region, in a first oil temperature region where the detection deviation of the main pressure detection sensor 29 is large relative to the oil temperature T. Therefore, the target differential pressure ΔP can be appropriately set according to the changes in the detection deviation of the main pressure detection sensor 29 caused by different oil temperature regions, thus further reducing the excess of the target main pressure tPL caused by the target differential pressure ΔP.

[0077] More specifically, in step S4, the target differential pressure setting module 353 sets the target differential pressure in the low oil temperature region LT (referencing the first oil temperature region). Figure 7 ) and high oil temperature zone HT (refer to Figure 7 The target pressure difference ΔP is set to be the intermediate oil temperature region CT (refer to) between the low oil temperature region LT and the high oil temperature region HT, which is smaller than the detection deviation of the main pressure detection sensor 29. Figure 7 )big.

[0078] Therefore, by setting a larger target pressure difference ΔP in the low oil temperature region LT and high oil temperature region HT where the detection deviation of the main pressure sensor 29 is large, and setting a smaller target pressure difference ΔP in the intermediate oil temperature region CT where the detection deviation of the main pressure sensor 29 is small, the target pressure difference ΔP can be appropriately set according to the changes in the detection deviation of the main pressure sensor 29 caused by different oil temperature regions. This further reduces the excess of the target main pressure tPL caused by the target pressure difference ΔP.

[0079] Furthermore, such as Figure 7 As shown, in step S4, the target differential pressure setting module 353 sets the target differential pressure ΔP to constant in the oil temperature region (e.g., the intermediate oil temperature region CT) where the detection deviation of the main pressure detection sensor 29 is constant.

[0080] On the other hand, such as Figure 7 As shown, in step S4, the target differential pressure setting module 353 sets the target differential pressure ΔP differently depending on the oil temperature T in the oil temperature region where the detection deviation of the main pressure detection sensor 29 changes (e.g., an adjacent low oil temperature region LT1 adjacent to the intermediate oil temperature region CT of the low oil temperature region LT, or an adjacent high oil temperature region HT1 adjacent to the intermediate oil temperature region CT of the high oil temperature region HT). Furthermore, from the viewpoint of further improving the accuracy of the target differential pressure ΔP, it is preferable that the target differential pressure setting module 353 sets the target differential pressure ΔP to a larger value as the detection deviation of the main pressure detection sensor 29 increases.

[0081] like Figure 7 As shown, the same trend is observed for the change in the target pressure difference ΔP set according to the oil temperature region, whether under high pressure (target main pressure tPL) above 2.0 MPa or low pressure (target main pressure tPL) below 1.5 MPa. That is, the target pressure difference ΔP is relatively large in the low oil temperature region LT and the high oil temperature region HT, and relatively small in the intermediate oil temperature region CT, located between the low oil temperature region LT and the high oil temperature region HT. Therefore, the target pressure difference ΔP can be effectively reduced in the intermediate oil temperature region CT, where fuel economy is better.

[0082] Next, in step S5, the target main pressure setting module 354 sets the target main pressure tPL as the target value of the main pressure PL based on the target pulley pressure tPP output from the target pulley pressure selection module 352 and the target pressure difference ΔP output from the target pressure difference setting module 353.

[0083] Specifically, in step S5, the target main pressure setting module 354 sets the target main pressure tPL to the sum of the target pulley pressure tPP and the target pressure difference ΔP. Then, the target main pressure setting module 354 outputs the set target main pressure tPL to the loop control command generation module 355, proceeding to step S6.

[0084] Next, in step S6, the transmission controller 2 controls the oil pressure control circuit 1 to adjust the detected primary pulley pressure Ppri, secondary pulley pressure Psec and main pressure PL to the target primary pulley pressure tPpri, target secondary pulley pressure tPsec and target main pressure tPL, respectively.

[0085] Specifically, in step S6, the loop control command generation module 355 generates a loop control command for controlling the hydraulic control loop 1 based on the primary pulley pressure Ppri, secondary pulley pressure Psec and main pressure PL output from the input interface 31, the target primary pulley pressure tPpri and target secondary pulley pressure tPsec output from the target pulley pressure setting module 351, and the target main pressure tPL output from the target main pressure setting module 354.

[0086] More specifically, in step S6, the loop control command generation module 355 generates loop control commands to adjust the primary pulley pressure Ppri, secondary pulley pressure Psec, and main pressure PL to target primary pulley pressure tPpri, target secondary pulley pressure tPsec, and target main pressure tPL, respectively. Then, the loop control command generation module 355 outputs the generated loop control commands to the hydraulic control loop 1 via the output interface 32.

[0087] Then, the hydraulic control loop 1 controls the primary pulley pressure Ppri, secondary pulley pressure Psec and main pressure PL based on the loop control command output from the loop control command generation module 355, so that the primary pulley pressure Ppri, secondary pulley pressure Psec and main pressure PL are adjusted to the target primary pulley pressure tPpri, target secondary pulley pressure tPsec and target main pressure tPL respectively, and returns to step S1.

[0088] (Effects)

[0089] Next, the main effects of this embodiment will be explained.

[0090] (1) The transmission TM of this embodiment includes: a primary pulley PRI; a secondary pulley SEC; a belt BLT (transmission component) wound around the primary pulley PRI and the secondary pulley SEC; a mechanical oil pump MP or an electric oil pump EP (oil pump) for supplying oil; and an oil pressure control circuit 1 for regulating the oil supplied by the mechanical oil pump MP or the electric oil pump EP (oil pump) to an initial pressure, i.e., a main pressure PL, which is the primary pulley pressure Ppri supplied to the primary pulley PRI and the secondary pulley pressure Psec supplied to the secondary pulley SEC; and a main pressure detection circuit for detecting the main pressure PL. Sensor 29 (main pressure detection unit); transmission controller 2 (controller) of control oil pressure control circuit 1, the transmission controller 2 (controller) selects the higher of the target value of primary pulley pressure Ppri and the target value of secondary pulley pressure Psec as the target pulley pressure tPP, and sets the target pressure difference ΔP variably according to oil temperature T, and sets the target value of main pressure PL, i.e. target main pressure tPL, to the sum of target pulley pressure tPP and target pressure difference ΔP, and controls oil pressure control circuit 1 so that the detected main pressure PL is adjusted to the target main pressure tPL.

[0091] (4) The control method of the transmission TM in this embodiment, wherein the transmission TM includes: a primary pulley PRI; a secondary pulley SEC; a belt BLT (transmission component) wound around the primary pulley PRI and the secondary pulley SEC; a mechanical oil pump MP or an electric oil pump EP (oil pump) for supplying oil; and an oil pressure that adjusts the oil supplied by the mechanical oil pump MP or the electric oil pump EP to an initial pressure, i.e., a main pressure PL, for supplying the primary pulley pressure Ppri to the primary pulley PRI and the secondary pulley pressure Psec to the secondary pulley SEC. Control loop 1, the control method of the transmission TM includes: a main pressure detection step, detecting the main pressure PL; a setting step, selecting the higher of the target value of the primary pulley pressure Ppri and the target value of the secondary pulley pressure Psec as the target pulley pressure tPP, and variably setting the target pressure difference ΔP according to the oil temperature T, setting the target value of the main pressure PL, i.e. the target main pressure tPL, as the sum of the target pulley pressure tPP and the target pressure difference ΔP; and a control step, controlling the oil pressure control loop 1 so that the detected main pressure PL is adjusted to the target main pressure tPL.

[0092] (5) The program of the embodiment is an executable program controlled by the CPU (computer) of the transmission TM, wherein the transmission TM includes: a primary pulley PRI; a secondary pulley SEC; a belt BLT (transmission component) wound around the primary pulley PRI and the secondary pulley SEC; a mechanical oil pump MP or an electric oil pump EP (oil pump) for supplying oil; and an initial pressure, i.e., a main pressure P, for adjusting the pressure of the oil supplied by the mechanical oil pump MP or the electric oil pump EP (oil pump) to a primary pulley pressure Ppri supplied to the primary pulley PRI and a secondary pulley pressure Psec supplied to the secondary pulley SEC. The hydraulic control circuit (1) of L, wherein the program causes the CPU (computer) to execute the following steps: main pressure detection step, detecting the main pressure PL; setting step, selecting the higher of the target value of the primary pulley pressure Ppri and the target value of the secondary pulley pressure Psec as the target pulley pressure tPP, and variably setting the target pressure difference ΔP according to the oil temperature T, setting the target value of the main pressure PL, i.e. the target main pressure tPL, to the sum of the target pulley pressure tPP and the target pressure difference ΔP; control step, controlling the hydraulic control circuit 1 so that the detected main pressure PL is adjusted to the target main pressure tPL.

[0093] Based on these structures, the target pressure difference ΔP used to set the target main pressure tPL can be variably set according to the oil temperature T. Therefore, compared to the case where the target pressure difference ΔP is a fixed value, the excess of the target main pressure tPL caused by the target pressure difference ΔP can be further reduced. As a result, the drive torque of the mechanical oil pump MP or the electric oil pump EP can be reduced.

[0094] (2) In the transmission TM of this embodiment, the transmission controller 2 (controller) sets the target pressure difference ΔP to be larger than that of the second oil temperature region where the detection deviation of the main pressure detection sensor 29 (main pressure detection unit) relative to the oil temperature T is large in the first oil temperature region.

[0095] According to this structure, since the target pressure difference ΔP can be appropriately set according to the change in the detection deviation of the main pressure detection sensor 29 caused by different oil temperature zones, the excess amount of the target main pressure tPL caused by the target pressure difference ΔP can be further reduced.

[0096] (3) In the transmission TM of this embodiment, the transmission controller 2 (controller) sets the target pressure difference ΔP in the low oil temperature region LT and the high oil temperature region HT, which are the first oil temperature region, to be larger than the detection deviation and the intermediate oil temperature region CT, which is the second oil temperature region, and is located between the low oil temperature region LT and the high oil temperature region HT.

[0097] According to this structure, by setting a larger target pressure difference ΔP in the low oil temperature region LT and the high oil temperature region HT where the detection deviation of the main pressure sensor 29 is large, and setting a smaller target pressure difference ΔP in the intermediate oil temperature region CT where the detection deviation of the main pressure sensor 29 is small, the target pressure difference ΔP can be appropriately set according to the changes in the detection deviation of the main pressure sensor 29 caused by different oil temperature regions. This can further reduce the excess of the target main pressure tPL caused by the target pressure difference ΔP.

[0098] The embodiments of the present invention have been described above. However, the above embodiments are merely examples of the application of the present invention and are not intended to limit the technical scope of the present invention to the specific structures of the above embodiments.

[0099] Symbol Explanation

[0100] 1: Hydraulic control circuit

[0101] 2: Transmission controller (controller)

[0102] 29: Main pressure detection sensor (main pressure detection unit)

[0103] 30: Oil temperature detection sensor

[0104] 35: Loop control device

[0105] EP: Electric oil pump (oil pump)

[0106] MP: Mechanical oil pump (oil pump)

[0107] TM: Transmission (Belt-type Continuously Variable Transmission)

[0108] PRI: Primary pulley

[0109] SEC: Secondary pulley

[0110] BLT: Belt (transfer component)

Claims

1. A transmission, comprising: Primary pulley; Secondary pulley; A transmission component, which is wound around the primary pulley and the secondary pulley; An oil pump supplies oil. The hydraulic control circuit regulates the pressure of the oil supplied by the oil pump to the main pressure, which is the initial pressure of the primary pulley pressure supplied to the primary pulley and the secondary pulley pressure supplied to the secondary pulley. The main pressure detection unit detects the main pressure. The controller controls the hydraulic control circuit. The controller selects the higher of the target values ​​of the primary pulley pressure and the secondary pulley pressure as the target pulley pressure, and variably sets the target pressure difference according to the oil temperature. This target pressure difference includes the detection deviation of the main pressure detection unit, which varies according to the oil temperature. The target value of the main pressure, i.e., the target main pressure, is set as the sum of the target pulley pressure and the target pressure difference. The controller then controls the oil pressure control loop to adjust the detected main pressure to the target main pressure.

2. The transmission as claimed in claim 1, wherein, The controller sets the target differential pressure to be larger than that in the second oil temperature region where the detection deviation is smaller than that in the first oil temperature region, when the detection deviation is large in the first oil temperature region.

3. The transmission as claimed in claim 2, wherein, In the first oil temperature region, namely the low oil temperature region and the high oil temperature region, the controller sets the target pressure difference to be larger than the detection deviation and located in the middle oil temperature region, which is the second oil temperature region, between the low oil temperature region and the high oil temperature region.

4. A control method for a transmission, the transmission comprising: a primary pulley, a secondary pulley, a transmission component wound around the primary pulley and the secondary pulley, an oil pump for supplying oil, and an oil pressure control circuit for adjusting the pressure of the oil supplied by the oil pump to an initial pressure, i.e., a main pressure, for supplying a primary pulley pressure to the primary pulley and a secondary pulley pressure to the secondary pulley, wherein... The control method for the transmission includes: The main pressure detection step involves detecting the main pressure. The control steps involve selecting the higher of the target values ​​for the primary pulley pressure and the secondary pulley pressure as the target pulley pressure, variably setting the target pressure difference based on the oil temperature (this target pressure difference includes the detection deviation of the main pressure detection unit, which varies with the oil temperature), setting the target value of the main pressure (i.e., the target main pressure) as the sum of the target pulley pressure and the target pressure difference, and controlling the oil pressure control loop to adjust the detected main pressure to the target main pressure.

5. A storage medium storing a program, which is a computer-executable program for controlling a transmission, the transmission comprising: a primary pulley, a secondary pulley, a transmission component wound around the primary pulley and the secondary pulley, an oil pump for supplying oil, and an oil pressure control circuit for adjusting the pressure of the oil supplied by the oil pump to an initial pressure, i.e., a main pressure, for supplying a primary pulley pressure to the primary pulley and a secondary pulley pressure to the secondary pulley, wherein... The program causes the computer to perform the following steps: The main pressure detection step involves detecting the main pressure. The control steps involve selecting the higher of the target values ​​for the primary pulley pressure and the secondary pulley pressure as the target pulley pressure, variably setting the target pressure difference based on the oil temperature (the target pressure difference includes the detection deviation of the main pressure detection unit, which varies with the oil temperature), setting the target value of the main pressure (i.e., the target main pressure) as the sum of the target pulley pressure and the target pressure difference, and controlling the oil pressure control loop to adjust the detected main pressure to the target main pressure.

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