Controller for belt type stepless speed change device

Abstract

To provide a controller for belt type stepless speed change device that can store data related to the situation in which a belt slips separately from data related to the situation in which the belt is broken.SOLUTION: A stepless speed change device 50 is configured to have a belt 56 wound around a primary pulley 52 and a secondary pulley 54. An electronic controller 90 comprises: (a) an abnormality determination part 90d which determines whether the belt 56 is normal based upon an input shaft rotating speed Nin or speed change ratio γ of a stepless speed change device 50; (b) a temporary storage part 90e which temporarily stores predetermined data related to the current situation if it is determined that the belt 56 is abnormal; and (c) a storage part 90f which stores the temporarily stored predetermined data as data when the belt 56 slips if it is determined that the belt 56 is normal within a predetermined time T after it is determined that the belt 56 is abnormal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control device for a belt-type continuously variable transmission configured by wrapping a belt around a primary pulley and a secondary pulley. [Background technology]

[0002] There are known control devices for belt-type continuously variable transmissions configured with a belt wound around a primary pulley and a secondary pulley, such as that described in Patent Document 1. The control device described in Patent Document 1 proposes detecting belt slippage based on a sudden increase in the rotational speed of the primary pulley, and storing data relating to the situation at the time the belt slippage is detected. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-116045 Summary of the Invention [Problem to be solved by the invention]

[0004] Storing data on the situation when belt slippage occurs is extremely effective for fault analysis. However, the behavior of a sudden increase in the rotational speed of the primary pulley when belt slippage occurs also occurs when the belt breaks. Therefore, the stored data is a mixture of data on the situation when belt slippage occurs and data on the situation when belt breakage occurs, which creates a problem in analyzing faults related to belt slippage.

[0005] The present invention has been made against the background of the above circumstances, and its purpose is to provide a control device for a belt-type continuously variable transmission that can store data relating to the situation when belt slippage occurs separately from data relating to the situation when belt breakage occurs. [Means for solving the problem]

[0006] The gist of the present invention is a control device for a belt-type continuously variable transmission configured by a belt wound around a primary pulley and a secondary pulley, comprising: (a) a judgment unit that judges whether the belt is normal or abnormal based on the rotational speed of the primary pulley or the gear ratio of the belt-type continuously variable transmission; (b) a temporary memory unit that, if it is judged that the belt is abnormal, temporarily stores predetermined data relating to the situation at that time; and (c) a memory unit that, if it is judged that the belt is normal within a predetermined time after it is judged that the belt is abnormal, stores the temporarily stored predetermined data as data relating to the situation when slippage occurs in the belt. [Effects of the Invention]

[0007] The control device of the present invention includes: (a) a determination unit that determines whether the belt is normal or abnormal based on the rotational speed of the primary pulley or the gear ratio of the belt-type continuously variable transmission; (b) a temporary storage unit that temporarily stores predetermined data related to the situation at the time when the belt is determined to be abnormal; and (c) a storage unit that stores the temporarily stored predetermined data as data related to the situation when the belt slips when the belt is determined to be normal within a predetermined time after the belt is determined to be abnormal. The configuration of (c) allows the data related to the situation when the belt slips to be stored separately from the data related to the situation when the belt breaks. This reduces obstacles to analyzing belt slippage. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a vehicle equipped with an electronic control device according to an embodiment of the present invention, and is also a functional block diagram showing the main parts of control functions for various controls in the vehicle. [Figure 2] 2 is an example of a flowchart illustrating a control operation of the electronic control device shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. [Example]

[0010] FIG. 1 is a schematic diagram of a vehicle 10 equipped with an electronic control device 90 according to an embodiment of the present invention, and is also a functional block diagram showing the main parts of control functions for various controls in the vehicle 10.

[0011] The vehicle 10 includes an engine 12, a pair of drive wheels 14, and a power transmission device 16 provided in a power transmission path between the engine 12 and the pair of drive wheels 14, all of which are well-known configurations. The power transmission device 16 includes, in order from the engine 12 side, a torque converter 20, a forward / reverse switching device 24, an input shaft 28, a belt-type continuously variable transmission 50 (hereinafter simply referred to as "continuously variable transmission 50"), an output shaft 30, a reduction gear device 32, and a differential 34, all of which are well-known configurations, within a case 18 which is a non-rotating member. The vehicle 10 also includes a hydraulic control circuit 40 and an electronic control device 90.

[0012] The hydraulic control circuit 40 uses, for example, hydraulic oil discharged by the oil pump 38 as the source pressure and supplies control hydraulic pressure to each hydraulic actuator that controls the effective diameter of the primary pulley 52 and the secondary pulley 54.

[0013] The continuously variable transmission 50 is a well-known belt-type continuously variable transmission that includes a primary pulley 52 having a variable effective diameter that is an input side member connected to the input shaft 28, a secondary pulley 54 having a variable effective diameter that is an output side member connected to the output shaft 30, and a belt 56 that is wound between the primary pulley 52 and the secondary pulley 54.

[0014] In the continuously variable transmission 50, the hydraulic control circuit 40, which is controlled by an electronic control device 90 (described later), changes the V-groove width of the primary pulley 52 and the secondary pulley 54 to change the loop diameter (effective diameter) of the belt 56, changing the speed ratio γ (=input shaft rotation speed Nin [rpm] / output shaft rotation speed Nout [rpm]) of the continuously variable transmission 50, and also controls the frictional force between the primary pulley 52 and the belt 56 and the secondary pulley 54 so as to prevent slippage of the belt 56. The input shaft rotation speed Nin is the rotational speed of the input shaft 28 and is equal to the rotational speed of the primary pulley 52, and the output shaft rotation speed Nout is the rotational speed of the output shaft 30 and is equal to the rotational speed of the secondary pulley 54.

[0015] The electronic control unit 90 includes, for example, a so-called microcomputer, and performs signal processing in accordance with pre-stored programs to execute various controls of the vehicle 10. The electronic control unit 90 corresponds to the "control unit" of the present invention.

[0016] The electronic control device 90 receives various signals based on detection values ​​from various sensors provided on the vehicle 10 (e.g., accelerator opening sensor 70, vehicle speed sensor 72, engine rotation speed sensor 74, input shaft rotation speed sensor 76, output shaft rotation speed sensor 78, and shift position sensor 80) (e.g., accelerator opening θacc [%] representing the magnitude of the driver's acceleration operation, vehicle speed V [km / h], engine rotation speed Ne [rpm] which is the rotation speed of the engine 12, input shaft rotation speed Nin, output shaft rotation speed Nout, and a signal representing the operating position POS of the shift lever 62 provided on the shift operation device 60).

[0017] The electronic control device 90 outputs an engine control signal Se to the engine 12 for controlling the operation of the engine 12, and outputs hydraulic control signals Sp to the hydraulic control circuit 40. The hydraulic control circuit 40 includes pulley control signals for controlling the speed change of the continuously variable transmission 50 and belt clamping pressure, forward / reverse control signals for controlling the engagement and disengagement of the engagement devices in the forward / reverse switching device 24, and control signals for controlling the engagement and disengagement of the lock-up clutch of the torque converter 20. The hydraulic control circuit 40 performs speed change control of the continuously variable transmission 50, belt clamping pressure control, etc. based on the hydraulic control signals Sp.

[0018] The electronic control device 90 functionally comprises an engine control unit 90a, a transmission control unit 90b, an engagement device connection / disconnection control unit 90c, an abnormality determination unit 90d, a temporary storage unit 90e, and a storage unit 90f.

[0019] The engine control unit 90a controls the engine 12 to output a required driving force Frdem [N], which is, for example, a driving force required of the vehicle 10. The transmission control unit 90b controls the continuously variable transmission 50 so that the gear ratio γ becomes a target gear ratio γ_tgt. The target gear ratio γ_tgt is a target value of the gear ratio γ. For example, the required driving force Frdem is calculated by applying the actual accelerator opening θacc and vehicle speed V to a relationship between the accelerator opening θacc, vehicle speed V, and the required driving force Frdem, which has been determined in advance experimentally or by design and stored. For example, the target gear ratio γ_tgt is calculated by applying the actual accelerator opening θacc and vehicle speed V to a relationship between the accelerator opening θacc, vehicle speed V, and the target gear ratio γ_tgt, which has been determined in advance experimentally or by design and stored. The engagement device engagement / disengagement control unit 90c controls engagement / disengagement of the engagement devices in the forward / reverse switching device 24 in accordance with the operation position POS of the shift lever 62.

[0020] The abnormality determination unit 90d determines whether the gear ratio γ is stable. For example, if the ratio α (=γ / γ_tgt) of the gear ratio γ to the target gear ratio γ_tgt is within a predetermined ratio range α_jdg including 1 and the change amount per unit time of the gear ratio γ is Δγ[s -1] is equal to or less than a predetermined change amount Δγ_jdg (>0), the gear ratio γ is determined to be in a stable state. The predetermined ratio range α_jdg is a predetermined range that is determined experimentally or by design in advance, in which the gear ratio control of the continuously variable transmission 50 is performed normally. The predetermined change amount Δγ_jdg is a predetermined amount that is determined experimentally or by design in advance, in order to determine whether slippage or breakage has occurred in the belt 56. The abnormality determination unit 90d determines whether the input shaft rotation speed Nin or the gear ratio γ has suddenly changed, that is, whether the gear ratio control of the continuously variable transmission 50 has changed from a state in which it was performing normally to an abnormal state. For example, the change amount ΔNin[s -1 If the change Δγ exceeds a predetermined change amount ΔNin_jdg (>0), it is determined that the input shaft rotation speed Nin has changed suddenly. The predetermined change amount ΔNin_jdg is a predetermined amount determined experimentally or by design in order to determine whether slippage or breakage has occurred in the belt 56. For example, if the change amount Δγ exceeds the predetermined change amount Δγ_jdg, it is determined that the gear ratio γ has changed suddenly. If slippage or breakage occurs in the belt 56, the torque transmitted between the primary pulley 52 and the secondary pulley 54 suddenly decreases. This causes a sudden decrease in load, for example, from the perspective of the engine 12 connected to the input shaft 28 of the primary pulley 52, causing a sudden increase in the input shaft rotation speed Nin and a corresponding sudden increase in the gear ratio γ. In this way, the abnormality determination unit 90d determines whether the belt 56 is normal or abnormal based on the input shaft rotation speed Nin or the gear ratio γ. The input shaft rotation speed Nin corresponds to the "rotation speed of the primary pulley" in the present invention, and the abnormality determination section 90d corresponds to the "determination section" in the present invention.

[0021] When the abnormality determination unit 90d determines that the input shaft rotation speed Nin or the gear ratio γ has changed from a stable state to a state where it has suddenly changed, i.e., that the belt 56 is abnormal, the temporary storage unit 90e temporarily stores relevant data at that time. The "relevant data" corresponds to the "predetermined data related to the situation" in this invention. The relevant data is predetermined data, including, for example, the vehicle speed V and engine torque, at the time when the input shaft rotation speed Nin or the gear ratio γ suddenly changed, which is necessary for analyzing a malfunction due to slippage of the belt 56.

[0022] When the temporary storage unit 90e temporarily stores the related data, the abnormality determination unit 90d determines whether the input shaft rotation speed Nin or the gear ratio γ has recovered to a stable state within a predetermined time T [s] starting from the time when it is determined that the input shaft rotation speed Nin or the gear ratio γ has suddenly changed. Note that the predetermined time T is a predetermined time determined experimentally or by design as the period until the input shaft rotation speed Nin or the gear ratio γ has recovered to a stable state even if temporary slippage occurs in the belt 56.

[0023] If the abnormality determination unit 90d determines that the input shaft rotation speed Nin or the gear ratio γ has recovered to a stable state within the predetermined time T, i.e., that the belt 56 is normal within the predetermined time T, the memory unit 90f stores the temporarily stored associated data as data relating to a situation in which slippage has occurred in the belt 56. If the abnormality determination unit 90d determines that the input shaft rotation speed Nin or the gear ratio γ has not recovered to a stable state within the predetermined time T, the memory unit 90f stores the temporarily stored associated data as data relating to a situation in which breakage has occurred in the belt 56.

[0024] Fig. 2 is an example of a flowchart illustrating the control operation of the electronic control device 90 shown in Fig. 1. The flowchart of Fig. 2 is repeatedly executed, for example, while the power transmission device 16 is running in a normal state.

[0025] First, in step S10 (hereinafter, "step" will be omitted), it is determined whether the gear ratio γ of the continuously variable transmission 50 is stable. If the determination in S10 is YES, then in S20 it is determined whether the input shaft rotation speed Nin or the gear ratio γ has suddenly changed. If the determination in S10 is NO, that is, if the gear ratio γ of the continuously variable transmission 50 was not stable from the beginning, the relevant data is not stored and the process returns. If the determination in S20 is YES, then in S30 the relevant data at that time is temporarily stored. If the determination in S20 is NO, the process returns. After S30 is executed, it is determined in S40 whether the input shaft rotation speed Nin or the gear ratio γ has returned to a stable state. If the determination in S40 is YES, then in S50 the relevant data temporarily stored in S30 is stored as data relating to a situation in which slippage has occurred in the belt 56. After S50 is executed, the process returns. If the determination in S40 is NO, then in S60 it is determined whether or not a predetermined time T has elapsed. If the determination in S60 is NO, then S40 is executed again. If the determination in S60 is YES, then in S70 the related data temporarily stored in S30 is stored as data relating to the situation in which the belt 56 broke. After execution of S70, the process ends.

[0026] According to this embodiment, the system includes: (a) an abnormality determination unit 90d that determines whether the belt 56 is normal or abnormal based on the input shaft rotation speed Nin or the speed ratio γ of the continuously variable transmission 50; (b) a temporary storage unit 90e that temporarily stores associated data when it is determined that the belt 56 is abnormal; and (c) a storage unit 90f that stores the temporarily stored associated data as data when slippage occurs in the belt 56 when it is determined that the belt 56 is normal within a predetermined time T after it was determined that the belt 56 is abnormal. The configuration of (c) above allows associated data when slippage occurs in the belt 56 to be stored separately from associated data when a break occurs in the belt 56. This reduces obstacles to analyzing a malfunction due to slippage of the belt 56.

[0027] The above-described embodiments of the present invention are merely examples, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit of the present invention. [Explanation of symbols]

[0028] 50: Belt-type continuously variable transmission, 52: Primary pulley, 54: Secondary pulley, 56: Belt, 90: Electronic control device (control device), 90d: Abnormality determination unit (determination unit), 90e: Temporary storage unit, 90f: Storage unit, Nin: Input shaft rotation speed (rotation speed of primary pulley), T: Predetermined time, γ: Speed ​​ratio

Claims

[Claim 1] A control device for a belt-type continuously variable transmission configured by wrapping a belt around a primary pulley and a secondary pulley, a determination unit that determines whether the belt is normal or abnormal based on the rotation speed of the primary pulley or the speed ratio of the belt-type continuously variable transmission; a temporary storage unit that temporarily stores predetermined data relating to the situation at the time when it is determined that the belt is abnormal; and a storage unit that stores the temporarily stored predetermined data as data relating to a situation in which slippage occurs in the belt when the belt is determined to be normal within a predetermined time after the belt is determined to be abnormal. A control device for a belt-type continuously variable transmission.

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