Abnormality diagnosis device for vehicle power transmission device

Abstract

To provide an abnormality diagnosis device for vehicle power transmission device capable of suppressing wrong diagnosis that belt-cutting abnormality occurs on a belt-type continuously-variable transmission.SOLUTION: An abnormality diagnostic device 100 includes: (a) a primary rotation sensor 72 (first detection part) detecting an input-side rotation state of a belt-type continuously-variable transmission 50; (b) a secondary rotation sensor 74 (second detection part) detecting an output-side rotation state of the belt-type continuously-variable transmission 50; and (c) an electronic control device 90 (determination part) performing a temporary determination that a belt-cutting abnormality occurs when the input-side rotation state of the belt-type continuously-variable transmission 50 is detected and the output-side rotation state of the belt-type continuously-variable transmission 50 is not detected in a stop state where a shift range is an N-range, and performing determination that the belt-cutting abnormality occurs when the output-side rotation state of the belt-type continuously-variable transmission 50 is detected during travelling after performing the temporary determination.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an abnormality diagnosis device for a vehicle power transmission device that transmits power via a belt-type continuously variable transmission. [Background technology]

[0002] There is known a vehicle power transmission device in which a first power transmission path via a gear mechanism and a second power transmission path via a belt-type continuously variable transmission are provided in parallel as power transmission paths for transmitting power from a driving power source from an input shaft to an output shaft. For example, there is one described in Patent Document 1. Patent Document 1 discloses a device that calculates a gear ratio of the belt-type continuously variable transmission based on a detection value of a first rotation speed sensor that detects the rotation speed of the input side of the belt-type continuously variable transmission and a detection value of a second rotation speed sensor that detects the rotation speed of the output side of the belt-type continuously variable transmission, and diagnoses an abnormality such as a broken belt of the belt-type continuously variable transmission based on the calculated gear ratio. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2-57761 Summary of the Invention [Problem to be solved by the invention]

[0004] In the diagnosis of a broken belt abnormality described in Patent Document 1, even if the second rotational speed sensor fails and the rotational speed of the output side of the belt-type continuously variable transmission cannot be detected, a broken belt abnormality will be erroneously diagnosed.

[0005] The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide an abnormality diagnosis device for a vehicle power transmission device that can suppress erroneous diagnosis of a broken belt in a belt-type continuously variable transmission. [Means for solving the problem]

[0006] The gist of the present invention is to provide a power transmission device for a vehicle, the power transmission device including: (1) a first power transmission path via a gear mechanism and a second power transmission path via a belt-type continuously variable transmission, which are provided in parallel as power transmission paths for transmitting power of a drive power source from an input shaft to an output shaft; (2) a first clutch for connecting and disconnecting the power transmission of the first power transmission path is provided in the first power transmission path, and a second clutch for connecting and disconnecting the power transmission between the belt-type continuously variable transmission and the output shaft is provided in the second power transmission path; and (3) a device for diagnosing an abnormality such as a broken belt in the belt-type continuously variable transmission in a power transmission device for a vehicle, the power transmission device being configured to be switchable between gear running using the first power transmission path and belt running using the second power transmission path. The abnormality diagnosis device for a vehicle power transmission device includes: (a) a first detection unit that detects the rotational state of an input side of the belt-type continuously variable transmission; (b) a second detection unit that detects the rotational state of an output side of the belt-type continuously variable transmission; and (c) a judgment unit that makes a provisional judgment that an abnormality such as a belt break has occurred when the rotational state of the input side is detected by the first detection unit and the rotational state of the output side is not detected by the second detection unit in a stopped state with the shift range set to a non-driving range, and that makes a judgment that an abnormality such as a belt break has occurred when the rotational state of the output side is detected by the second detection unit during driving after the provisional judgment has been made. Effect of the Invention

[0007] According to the present invention, there is provided (a) a first detection unit that detects the rotation state of the input side of the belt-type continuously variable transmission, (b) a second detection unit that detects the rotation state of the output side of the belt-type continuously variable transmission, and (c) a determination unit that provisionally determines that an abnormality of belt breakage has occurred when the rotation state of the input side is detected by the first detection unit and the rotation state of the output side is not detected by the second detection unit in a stopped state with the shift range set to a non-driving range, and determines that an abnormality of belt breakage has occurred when the rotation state of the output side is detected by the second detection unit during driving after the provisional determination has been made. This prevents a false diagnosis of an abnormality of belt breakage from being made when it becomes impossible to detect the rotation speed of the output side of the belt-type continuously variable transmission. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a vehicle equipped with an abnormality diagnosis 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. [Diagram 2] 4 is an example of a time chart for determining that a belt breakage abnormality has occurred in the abnormality diagnosis device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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. EXAMPLES

[0010] 1 is a schematic configuration diagram of a vehicle 10 equipped with an abnormality diagnosis device 100 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. The vehicle 10 is equipped with an engine 12 which is a driving force source for traveling, a pair of driving wheels 14, a power transmission device 16 which transmits the power (driving force) output from the engine 12 to the pair of driving wheels 14, a hydraulic control circuit 60, and an electronic control device 90.

[0011] The engine 12 is a well-known internal combustion engine and corresponds to the "driving force source" in the present invention. The power transmission device 16 includes, in order from the engine 12 side, a torque converter 20, an input shaft 22, a speed change mechanism 24, an output shaft 30, a reduction gear device 34, a differential 38, and a pair of axles 40, which are well-known configurations. The power transmission device 16 corresponds to the "vehicle power transmission device" in the present invention. The speed change mechanism 24 is provided with a first power transmission path PT1 (hereinafter simply referred to as "first path PT1") and a second power transmission path PT2 (hereinafter simply referred to as "second path PT2") in parallel as power transmission paths that transmit power from the input shaft 22 to the output shaft 30, and one of them is configured to be selectively connectable. In this specification, unless otherwise specified, power is synonymous with torque or force.

[0012] The first path PT1 includes, in order from the input shaft 22 side, a forward / reverse switching device 26, a gear mechanism 28, and a clutch SOWC. The forward / reverse switching device 26 is mainly composed of, for example, a first clutch C1, a brake B1, and a double pinion type planetary gear device. The gear mechanism 28 has a stepped speed change function that configures one gear stage to change the rotation speed of the input shaft 22 and output it from the output shaft 30. The clutch SOWC can select a one-way lock state and a two-way lock state. In the one-way lock state, power can be transmitted from the input shaft 22 side to the output shaft 30 side during forward travel, but power transmission from the output shaft 30 side to the input shaft 22 side is blocked. In the two-way lock state, power can be transmitted between the input shaft 22 and the output shaft 30 during both forward travel and reverse travel. The second path PT2 includes, in order from the input shaft 22 side, a belt-type continuously variable transmission 50 (hereinafter simply referred to as "continuously variable transmission 50") and a second clutch C2. The continuously variable transmission 50 is a well-known belt-type continuously variable transmission including a primary pulley 52 on the input side, a secondary pulley 54 on the output side, and a transmission belt 56 wound between the primary pulley 52 and the secondary pulley 54. The second clutch C2 is an engagement device that connects and disconnects power transmission between the continuously variable transmission 50 and the output shaft 30 in the second path PT2.

[0013] In the vehicle 10, there are a gear driving mode in which gear driving is performed using the first path PT1, and a belt driving mode in which belt driving is performed using the second path PT2. The gear ratio γgear (=input shaft rotation speed Nin [rpm] / output shaft rotation speed Nout [rpm]) of the gear mechanism 28 is set to a value larger than the maximum gear ratio γcvt_max of the continuously variable transmission 50. The input shaft rotation speed Nin is the rotation speed of the input shaft 22, and the output shaft rotation speed Nout is the rotation speed of the output shaft 30. The gear driving is used when the vehicle 10 is in a relatively low vehicle speed range, and the belt driving is used when the vehicle 10 is in a relatively high vehicle speed range. In this way, the transmission mechanism 24 is configured to be able to switch between gear driving and belt driving.

[0014] The shift lever 80 can select, for example, any one of the P range, R range, N range, and D range, which are shift ranges that indicate the power transmission state of the vehicle 10. In the non-driving ranges of the P range and N range, the power transmission device 16 is in a neutral state (= a state in which both the first path PT1 and the second path PT2 are disconnected). The R range is a reverse driving range that allows reverse driving. The D range is a forward driving range that allows forward driving.

[0015] Hereinafter, unless otherwise specified, the first clutch C1, the second clutch C2, the brake B1, and the clutch SOWC will be collectively referred to as the "state control engagement device." The operating states of the state control engagement devices are controlled to switch the shift range and the driving mode. When the first clutch C1, the second clutch C2, and the brake B1 are all in the released state and the clutch SOWC is in the one-way lock state, the power transmission device 16 is in the neutral state. When the first clutch C1 is in the engaged state, the brake B1 and the second clutch C2 are all in the released state and the clutch SOWC is in the one-way lock state, the first path PT1 is connected to the D range for gear driving. When the first clutch C1 and the brake B1 are all in the released state, the second clutch C2 is in the engaged state, and the clutch SOWC is in the one-way lock state, the second path PT2 is connected to the D range for belt driving. When the first clutch C1 and the second clutch C2 are both in a released state, the brake B1 is in an engaged state, and the clutch SOWC is in a bidirectional lock state, the first path PT1 is connected and the R range for gear travel is established.

[0016] The hydraulic control circuit 60 supplies a control hydraulic pressure to each hydraulic actuator that controls the effective diameter of the primary pulley 52 and the secondary pulley 54 of the continuously variable transmission 50. The hydraulic control circuit 60 supplies a control hydraulic pressure to each hydraulic actuator that controls each operating state of the state control engagement device.

[0017] The electronic control device 90 includes a so-called microcomputer equipped with, for example, a CPU, a RAM, a ROM, an input / output interface, and the like, and the CPU executes various controls of the vehicle 10 by performing signal processing according to a program previously stored in the ROM while utilizing the temporary storage function of the RAM. Various signals based on detection values ​​by various sensors and the like (for example, an engine rotation sensor 70, a primary rotation sensor 72, a secondary rotation sensor 74, an output shaft rotation sensor 76, an accelerator opening sensor 78, a shift position sensor 82, and the like) provided in the vehicle 10 (for example, an engine rotation speed Ne [rpm] which is the rotation speed of the engine 12, a primary rotation speed Npri [rpm] which is the same value as the input shaft rotation speed Nin and which is the rotation speed of the primary pulley 52, a secondary rotation speed Nsec [rpm] which is the rotation speed of the secondary pulley 54, an output shaft rotation speed Nout corresponding to the vehicle speed V [km / h], an accelerator opening θacc [%], a shift position signal POSsh which indicates the position of the shift lever 80, and the like) are input to the electronic control device 90. The electronic control device 90 outputs various command signals (e.g., an engine control signal Se for controlling the engine 12, a hydraulic control signal Scvt for controlling the shifting of the continuously variable transmission 50 and the belt clamping pressure, etc., a hydraulic control signal Scbs for controlling each operating state of the state control engagement devices, etc.) to each device (e.g., the engine 12, the hydraulic control circuit 60, etc.) provided in the vehicle 10.

[0018] From here, we will explain the abnormality diagnosis device 100 that diagnoses abnormalities such as belt breakage in the continuously variable transmission 50. The abnormality diagnosis device 100 includes a primary rotation sensor 72, a secondary rotation sensor 74, and an electronic control device 90. The primary rotation sensor 72, the secondary rotation sensor 74, and the electronic control device 90 correspond to the "first detection unit," the "second detection unit," and the "determination unit" of the present invention, respectively.

[0019] The electronic control device 90 functionally comprises a vehicle stop determination unit 90a, a provisional determination unit 90b, a traveling state determination unit 90c, and a final determination unit 90d.

[0020] The vehicle stop determination unit 90a determines whether the vehicle is in a stopped state with the shift range set to N range. For example, when the vehicle speed V is equal to or lower than a predetermined vehicle speed determination value V_jdg, the vehicle is determined to be in a stopped state. The vehicle speed determination value V_jdg is a predetermined determination value, for example, a vehicle speed value slightly higher than zero in the vicinity of zero. At this time, the engine rotation speed Ne is an idle rotation speed, and the rotation of the engine 12 is transmitted to the input shaft 22 and the primary pulley 52 via the torque converter 20.

[0021] When it is determined that the vehicle is in a stopped state with the shift range set to the N range, the provisional determination unit 90b provisionally determines whether or not a belt breakage abnormality has occurred. When the primary rotation sensor 72 detects the rotation state of the primary pulley 52 and the secondary rotation sensor 74 does not detect the rotation state of the secondary pulley 54, the provisional determination unit 90b provisionally determines that a belt breakage abnormality has occurred. For example, when the primary rotation speed Npri is equal to or greater than a predetermined first speed determination value Npri_jdg and the secondary rotation speed Nsec is less than a predetermined second speed determination value Nsec_jdg, a provisional determination is made that a belt breakage abnormality has occurred. The provisional determination is made because there is a possibility that a belt breakage abnormality has not occurred and the secondary rotation sensor 74 has failed. The first speed determination value Npri_jdg and the second speed determination value Nsec_jdg are predetermined determination values ​​that are determined in advance to determine that the primary pulley 52 and the secondary pulley 54 are in a rotating state, respectively, and are, for example, rotation speed values ​​that are higher than zero and close to zero.

[0022] The running state determination unit 90c determines whether the vehicle 10 is in a running state. Even if an abnormality such as a broken belt occurs, the vehicle 10 can start by running in gear. After starting in gear running, when the vehicle speed V reaches a relatively high vehicle speed region where belt running is possible, the running mode is switched from the gear running mode to the belt running mode. Note that even if the running mode is switched to the belt running mode, if an abnormality such as a broken belt occurs, the vehicle 10 is in a running state by inertia.

[0023] When it is determined that the vehicle 10 is in a running state after it has been provisionally determined that the belt breakage abnormality has occurred, the main determination unit 90d determines whether or not the belt breakage abnormality has occurred. When the vehicle 10 is in a running state, the output shaft 30 rotates in response to the rotation of the pair of drive wheels 14. When the running mode of the vehicle 10 is a gear running mode, the second clutch C2 is in a released state, but the rotation of the output shaft 30 is transmitted to the secondary pulley 54 by the drag torque of the second clutch C2. When the running mode of the vehicle 10 is a belt running mode, the second clutch C2 is in an engaged state, so that the rotation of the output shaft 30 is transmitted to the secondary pulley 54 by the transmission torque of the second clutch C2. When the rotation state of the secondary pulley 54 is detected by the secondary rotation sensor 74, the main determination unit 90d determines that the belt breakage abnormality has occurred. For example, when the secondary rotation speed Nsec is equal to or greater than the second speed determination value Nsec_jdg, it is determined that the belt breakage abnormality has occurred. When the rotation state of the secondary pulley 54 is detected, the secondary rotation sensor 74 is functioning normally. Therefore, when the secondary rotation sensor 74 is in a normal state after the provisional determination, the main determination unit 90d determines that an abnormality such as a belt break has occurred. The determination by the main determination unit 90d is not a provisional determination, but a final determination.

[0024] Fig. 2 is an example of a time chart for determining whether or not a belt breakage has occurred in the abnormality diagnostic device 100. In Fig. 2, the horizontal axis represents time t [sec].

[0025] First, at time t1, the shift range is in the N range, the vehicle is stopped, the primary rotation speed Npri is equal to or greater than the first speed determination value Npri_jdg, and the secondary rotation speed Nsec is less than the second speed determination value Nsec_jdg, so that a provisional determination is made that an abnormality of belt breakage has occurred. In the period from time t2 (>t1) to time t3 (>t2), a control is executed to switch the shift range from the N range to the D range for gear driving. After time t4 (>t3), the engine rotation speed Ne increases due to accelerator operation, the vehicle speed V increases, and the primary rotation speed Npri increases. At this time, the rotation of the pair of drive wheels 14 is transmitted to the secondary pulley 54 via the output shaft 30 and the second clutch C2 (drag torque in the case of the gear driving mode, transmission torque in the case of the belt driving mode). At time t5 (>t4), when the secondary rotation speed Nsec becomes equal to or greater than the second speed determination value Nsec_jdg, a determination is made that an abnormality of belt breakage has occurred.

[0026] According to this embodiment, there are provided (a) a primary rotation sensor 72, (b) a secondary rotation sensor 74, and (c) an electronic control device 90 that provisionally determines that a belt break has occurred when the primary rotation sensor 72 detects the rotation state of the primary pulley 52 and the secondary rotation sensor 74 does not detect the rotation state of the secondary pulley 54 in a stopped state with the shift range set to N range, and determines that a belt break has occurred when the secondary rotation sensor 74 detects the rotation state of the secondary pulley 54 during driving after the provisional determination has been made. This prevents a misdiagnosis that a belt break has occurred when the secondary rotation sensor 74 is malfunctioning.

[0027] It should be noted that the above is an embodiment of the present invention, 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.

[0028] The primary rotation sensor 72 and the secondary rotation sensor 74 do not have to be capable of detecting the rotation speed as in the above-mentioned embodiment, but may be capable of detecting at least whether the primary pulley 52 and the secondary pulley 54 are in a rotating state or not. Furthermore, the vehicle 10 does not have to be configured to include the torque converter 20 as in the above-mentioned embodiment. For example, the present invention is also applicable to a vehicle in which the input shaft 22 is directly connected to the engine 12 and a starting clutch is provided to connect and disconnect the power transmission between the output shaft 30 and the pair of drive wheels 14. [Explanation of symbols]

[0029] 12: engine (driving force source), 16: power transmission device (vehicle power transmission device), 20: torque converter, 22: input shaft, 28: gear mechanism, 30: output shaft, 50: belt-type continuously variable transmission, 72: primary rotation sensor (first detection unit), 74: secondary rotation sensor (second detection unit), 90: electronic control device (determination unit), 100: abnormality diagnosis device, C1: first clutch, C2: second clutch, PT1: first power transmission path, PT2: second power transmission path

Claims

1. a first power transmission path via a gear mechanism and a second power transmission path via a belt-type continuously variable transmission are provided in parallel as power transmission paths for transmitting power of a driving power source from an input shaft to an output shaft; a first clutch that connects and disconnects the power transmission of the first power transmission path is provided in the first power transmission path, and a second clutch that connects and disconnects the power transmission between the belt-type continuously variable transmission and the output shaft is provided in the second power transmission path, An abnormality diagnosis device for a vehicle power transmission device, the abnormality diagnosis device diagnosing a belt breakage abnormality in a belt-type continuously variable transmission in the vehicle power transmission device configured to be switchable between gear running using the first power transmission path and belt running using the second power transmission path, A first detection unit that detects a rotation state of an input side of the belt-type continuously variable transmission; A second detection unit that detects a rotation state of an output side of the belt-type continuously variable transmission; a determination unit that provisionally determines that an abnormality such as a broken belt has occurred when the first detection unit detects the rotation state of the input side and the second detection unit does not detect the rotation state of the output side in a stopped state with the shift range set to a non-driving range, and that determines that an abnormality such as a broken belt has occurred when the second detection unit detects the rotation state of the output side during driving after the provisional determination has been made.

2. A power transmission device for a vehicle, comprising:

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