Control device for vehicle power transmission device

Abstract

To provide a control device for a vehicle power transmission device capable of suppressing gear rattling noise while suppressing fuel consumption worsening.SOLUTION: A power transmission device 16 includes a first power transmission route PT1 transmitting power via a belt-type non-stage transmission 50 and a second power transmission route PT2 transmitting power via a gear mechanism 26 as a speed reduction gear mechanism provided in parallel between an input axis 20 and an output axis 30. In the second power transmission route PT2, a first clutch C1 as a friction-type clutch and an engagement-type clutch D1 are provided sequentially from the side of the input axis 20. The electronic control device 90 executes drag torque increase control for increasing a drag torque Tt of the first clutch C1 when a vehicle drive state is in a gear rattling noise occurrence region where the gear rattling noise occurs in the engagement-type clutch D1 in a vehicle travelling time where power is transmitted using the first power transmission route PT1 and the engagement-type clutch D1 is in an engagement state.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a control device for a vehicle power transmission device that includes, in parallel between an input shaft and an output shaft, a first power transmission path that transmits power via a belt-type continuously variable transmission and a second power transmission path that transmits power via a reduction gear mechanism.

Background Art

[0002] There is known a vehicle power transmission device that includes, in parallel between an input shaft and an output shaft, a first power transmission path that transmits power via a belt-type continuously variable transmission and a second power transmission path that transmits power via a reduction gear mechanism. For example, the one described in Patent Document 1 is such a device. In the vehicle power transmission device described in Patent Document 1, a friction clutch and a meshing clutch are provided in the second power transmission path in order from the input shaft side.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the vehicle power transmission device described in Patent Document 1, when power is transmitted using the first power transmission path and the meshing clutch is in the meshed state during vehicle travel, if rotational fluctuations of the output shaft are input to the meshing clutch, a rattling sound (= tooth rattling sound) is generated. As a method of suppressing the rattling sound, it is conceivable to increase the belt clamping pressure to suppress the impact energy of the rattling. However, as the belt clamping pressure is increased, losses including the loss of the oil pump and the transmission loss in the belt-type continuously variable transmission increase, leading to deterioration of fuel efficiency.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a control device for a vehicle power transmission device that can suppress rattling noise while suppressing deterioration in fuel consumption.

Means for Solving the Problems

[0006] The gist of the present invention is to provide, in parallel between an input shaft and an output shaft, a first power transmission path that transmits power via a belt-type continuously variable transmission and a second power transmission path that transmits power via a reduction gear mechanism, and in the second power transmission path, a friction clutch and an engagement clutch are provided in order from the input shaft side. A control device for a vehicle power transmission device, wherein when power is transmitted using the first power transmission path and the engagement clutch is in an engaged state during vehicle running, if the vehicle operation state is in a predetermined operation region where rattling noise is generated by the engagement clutch, at least the sliding torque increase control for increasing the sliding torque of the friction clutch and the pinch pressure increase control for increasing the belt pinch pressure of the belt-type continuously variable transmission are executed.

Effects of the Invention

[0007] According to the present invention, when power is transmitted using the first power transmission path and the engagement clutch is in an engaged state during vehicle running, if the vehicle operation state is in a predetermined operation region where rattling noise is generated by the engagement clutch, at least the sliding torque increase control for increasing the sliding torque of the friction clutch and the pinch pressure increase control for increasing the belt pinch pressure of the belt-type continuously variable transmission are executed. The sliding torque increase control suppresses deterioration in fuel consumption more than the pinch pressure increase control. Therefore, compared with the case where only the pinch pressure increase control is executed, at least the sliding torque increase control is executed to suppress rattling noise while suppressing deterioration in fuel consumption.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiment for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiments, the drawings are appropriately simplified or deformed, and the dimensional ratios, shapes, etc. of each part are not necessarily accurately drawn.

Embodiment

[0010] FIG. 1 is a schematic configuration 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. The vehicle 10 includes an engine 12 as a driving power source for running, a pair of drive wheels 14, a power transmission device 16 that transmits the power (driving force) output from the engine 12 to the pair of drive wheels 14, a hydraulic control circuit 60, and an electronic control device 90.

[0011] The engine 12 is a well-known internal combustion engine. The power transmission device 16 includes, in order from the engine 12 side, a torque converter 18, an input shaft 20, a transmission mechanism 22, an output shaft 30, a reduction gear device 34, a differential 38, and a pair of axles 40, which are of well-known configurations. The power transmission device 16 corresponds to the "vehicle power transmission device" in the present invention. In the transmission mechanism 22, a first power transmission path PT1 (hereinafter referred to as the "first path PT1") and a second power transmission path PT2 (hereinafter referred to as the "second path PT2") are provided in parallel as power transmission paths for transmitting power from the input shaft 20 to the output shaft 30, and either one of them is configured to be selectively connectable. In this specification, when not particularly distinguished, power is synonymous with torque and force.

[0012] The first path PT1 includes, in order from the engine 12 side, a belt-type continuously variable transmission 50 (hereinafter simply referred to as the "continuously variable transmission 50") and a second clutch C2. The first path PT1 transmits power via the continuously variable transmission 50. 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 therebetween. The transmission belt 56 is a well-known compression-type transmission belt, for example, an endless loop. The second clutch C2 is, for example, a hydraulic friction engagement device that disconnects and connects the power transmission between the continuously variable transmission 50 and the output shaft 30 in the first path PT1.

[0013] The second path PT2 includes, in order from the engine 12 side, a forward / reverse switching device 24, a gear mechanism 26, and an engaging clutch D1. The second path PT2 transmits power via the gear mechanism 26. The gear ratio γgear (= input shaft rotational speed Nin [rpm] / output shaft rotational speed Nout [rpm]) of the gear mechanism 26 is greater than 1. The input shaft rotational speed Nin is the rotational speed of the input shaft 20, and the output shaft rotational speed Nout is the rotational speed of the output shaft 30. The gear mechanism 26 corresponds to the "speed reduction gear mechanism" in the present invention. The engaging clutch D1 has a well-known configuration including a synchromesh mechanism S1 as a synchronization mechanism for synchronizing its rotation when switching from a non-engaged state to an engaged state, for example. When the engaging clutch D1 is in the engaged state, there is play (= backlash) in the rotational direction between the engaging teeth. When the engaging teeth repeatedly undergo tooth surface separation and tooth surface collision in the rotational direction, a rattling sound is generated. The first clutch C1 and the brake B1 are, for example, hydraulic friction engagement devices.

[0014] Hereinafter, when the first clutch C1, the second clutch C2, the brake B1, and the engaging clutch D1 are not particularly distinguished, they are referred to as "engagement device CBD". For example, each operating state of the engagement device CBD is controlled by the hydraulic pressure supplied from a hydraulic actuator. The operating states include an engaged state (= including the engaged state), a slip state, and a released state (= including the non-engaged state). For example, when the hydraulic pressure supplied from the hydraulic actuator increases, it is set to the engaged state, and when the hydraulic pressure supplied from the hydraulic actuator decreases, it is set to the released state. The first clutch C1 corresponds to the "friction clutch" in the present invention.

[0015] In the vehicle 10, as driving modes, there are a belt driving mode in which belt driving is performed using the first path PT1 and a gear driving mode in which gear driving is performed using the second path PT2. The gear ratio γgear of the gear mechanism 26 is set to a value larger than the maximum gear ratio γcvt_max which is the maximum value of the gear ratio γcvt (= Nin / Nout) of the continuously variable transmission 50. The gear ratio γ of the transmission mechanism 22 becomes the gear ratio γgear in gear driving and becomes the gear ratio γcvt in belt driving. Gear driving is used when the vehicle 10 is in a relatively low vehicle speed range, and belt driving is used when the vehicle 10 is in a relatively high vehicle speed range. Thus, the transmission mechanism 22 is configured to be able to switch between gear driving and belt driving.

[0016] FIG. 2 is a diagram for explaining the switching of the driving modes in the forward driving of the power transmission device 16 shown in FIG. 1. In FIG. 2, “○” represents an engaged state, “△” represents a slipping state, and “×” represents a released state. During the gear driving mode, the belt driving mode (medium vehicle speed), the belt driving mode (high vehicle speed), and the switching of the driving modes between the gear driving mode and the belt driving mode (medium vehicle speed), the operating state of the engagement device CBD is controlled as shown in FIG. 2 respectively.

[0017] Returning to FIG. 1. The hydraulic control circuit 60 supplies control hydraulic pressure to each hydraulic actuator that controls the effective diameters of the primary pulley 52 and the secondary pulley 54 and each hydraulic actuator that controls the operating state of the engagement device CBD, taking the hydraulic oil discharged by an oil pump (not shown) as the source pressure.

[0018] The electronic control unit 90 is configured to include, for example, a so-called microcomputer, and executes various controls of the vehicle 10. Various signals (for example, the engine rotational speed Ne [rpm] which is the rotational speed of the engine 12, the primary rotational speed Npri (= Nin) [rpm] which is the rotational speed of the primary pulley 52, the secondary rotational speed Nsec [rpm] which is the rotational speed of the secondary pulley 54, the output shaft rotational speed Nout corresponding to the vehicle speed V [km / h], the accelerator opening θacc [%], the gear rotational speed Ng [rpm] which is the rotational speed of the gear 28 which is the rotational member on the output shaft 30 side of the first clutch C1, etc.) based on the detection values by various sensors etc. provided in the vehicle 10 (for example, the engine rotational speed sensor 70, the primary rotational speed sensor 72, the secondary rotational speed sensor 74, the output shaft rotational speed sensor 76, the accelerator opening sensor 78, the gear rotational speed sensor 80, etc.) are respectively input. From the electronic control unit 90, various command signals (for example, the engine control signal Se for controlling the engine 12, the hydraulic control signal Scvt for controlling the shift of the continuously variable transmission 50 and the belt clamping pressure Cp [Pa], etc., the hydraulic control signal Scbd for controlling each operating state of the engagement device CBD, etc.) are respectively output to each device (for example, the engine 12, the hydraulic control circuit 60, etc.) provided in the vehicle 10.

[0019] The electronic control unit 90 functionally includes a traveling state determination unit 90a, a abnormal noise generation region determination unit 90b, a draw torque increase control unit 90c, a rotational fluctuation determination unit 90d, and a clamping pressure increase control unit 90e. The electronic control unit 90 corresponds to the "control device" in the present invention.

[0020] The running state determination unit 90a determines whether the vehicle state is such that the belt is running and the meshing clutch D1 is in the meshed state. During vehicle running when the belt is running and the meshing clutch D1 is in the meshed state, the abnormal noise generation region determination unit 90b determines whether the vehicle operation state is within the rattling noise generation region. The rattling noise generation region is a predetermined region of the vehicle operation state in which the rattling noise generated by the meshing clutch D1 exceeds the allowable range. For example, based on a vehicle operation state map in which the relationship between the engine torque Te [Nm] which is the output torque of the engine 12, the engine rotational speed Ne, and the transmission ratio γcvt of the continuously variable transmission 50 and the region where the rattling noise exceeds the allowable range is experimentally or design - determined in advance, it is determined whether it is within the rattling noise generation region. For example, when the engine rotational speed Ne and the engine torque Te are low, their fluctuations (= pulsations) are more likely to be larger compared to when they are high. Also, when the transmission ratio γcvt is high, the deflection of the transmission belt 56 is more likely to be larger compared to when it is low. Therefore, when the engine rotational speed Ne and the engine torque Te are low and the transmission ratio γcvt is high, the rotational fluctuation of the secondary pulley 54 of the continuously variable transmission 50, that is, the rotational fluctuation of the output shaft 30, is more likely to be large. When the rotational fluctuation of the output shaft 30 is large, this rotational fluctuation is input to the meshing teeth on the output shaft 30 side in the meshing clutch D1, so the rattling noise is more likely to exceed the allowable range. Note that within the rattling noise generation region, due to the rattling of the meshing clutch D1, the fluctuation amount ΔNg which is the amount of change in the gear rotational speed Ng per unit time exceeds the first fluctuation amount determination value ΔNg_jdg1. The rattling noise generation region corresponds to the "predetermined operation region" in the present invention.

[0021] When the vehicle is running with the belt and the meshing clutch D1 in the meshed state, and it is determined that the vehicle operating state is within the rattling sound generation region, the drag torque increasing control unit 90c executes the drag torque increasing control. The drag torque increasing control is a control for increasing the drag torque Tt [Nm] of the first clutch C1 by changing the first clutch C1 from the released state to the slip state. The rattling sound is suppressed by increasing the drag torque Tt and suppressing the sensitivity of the side receiving the impact in the meshing clutch D1. If the drag torque Tt is increased too much during the execution of the drag torque increasing control, the heat generation amount of the first clutch C1 cannot withstand the heat load, or the adverse effect on the belt running becomes too large. Therefore, the drag torque increasing control executed to suppress the rattling sound has a limited application range compared to the clamping pressure increasing control described later.

[0022] The rotational fluctuation determination unit 90d determines whether the fluctuation amount ΔNg is less than or equal to the second fluctuation amount determination value ΔNg_jdg2. The second fluctuation amount determination value ΔNg_jdg2 is a predetermined determination value of the fluctuation amount ΔNg that is experimentally or designedly determined in advance so that the rattling sound is within the allowable range during the execution of the drag torque increasing control. If the fluctuation amount ΔNg exceeds the second fluctuation amount determination value ΔNg_jdg2 during the execution of the drag torque increasing control, the rattling sound is outside the allowable range. When the fluctuation amount ΔNg exceeds the second fluctuation amount determination value ΔNg_jdg2 during the execution of the drag torque increasing control, the drag torque increasing control unit 90c terminates the drag torque increasing control, and the clamping pressure increasing control unit 90e executes the clamping pressure increasing control. The clamping pressure increasing control is a control for increasing the belt clamping pressure Cp. By increasing the belt clamping pressure Cp, the fluctuation of the side colliding in the meshing clutch D1 is suppressed, and the rattling sound is suppressed.

[0023] FIG. 3 is an example of a flowchart for explaining the control operation of the electronic control device 90 shown in FIG. 1. The flowchart of FIG. 3 is repeatedly executed. First, in step (hereinafter, steps are omitted) S10, it is determined whether or not the belt is running and the meshing clutch D1 is in the meshed state. If the determination in S10 is YES, in S20, it is determined whether or not the vehicle driving state is within the rattling sound generation region. If the determination in S20 is YES, in S30, the drag torque increase control is executed, and in S40, it is determined whether or not the variation amount ΔNg is less than or equal to the second variation amount determination value ΔNg_jdg2. If the determination in S40 is YES, S20 is executed again. If the determination in S40 is NO, in S50, the drag torque increase control is terminated and the clamping pressure increase control is executed, and in S60, it is determined whether or not the vehicle driving state is within the rattling sound generation region. If the determination in S60 is YES, S60 is executed again. If the determination in S60 is NO, in S70, the clamping pressure increase control is terminated. If the determination in S10 is NO, if the determination in S20 is NO, and after the execution of S70, all result in a return.

[0024] FIG. 4 is an example of a time chart when the flowchart of FIG. 3 is executed. In FIG. 4, the horizontal axis represents time t [ms]. The solid lines indicating the belt clamping pressure Cp, the loss L [W] including the loss of the oil pump and the transmission loss in the continuously variable transmission 50, the hydraulic pressure Pc1, and the hydraulic pressure Pc2 in FIG. 4 are for this embodiment, and the dashed lines are for a comparative example in which only the clamping pressure increase control is executed. The description of the comparative example is omitted. The hydraulic pressure Pc1 is the output pressure of the hydraulic actuator that controls the operating state of the first clutch C1, and the hydraulic pressure Pc2 is the output pressure of the hydraulic actuator that controls the operating state of the second clutch C2.

[0025] First, at time t1, the switching from gear driving to belt driving is started. At time t2, the switching to belt driving is completed. At time t3, the vehicle driving state enters the rattling sound generation region, and the draw torque increase control is started. At time t4, the variation amount ΔNg exceeds the second variation amount determination value ΔNg_jdg2, the draw torque increase control is terminated, and the nip pressure increase control is started. At time t5, the vehicle driving state exits the rattling sound generation region, and the nip pressure increase control is terminated.

[0026] According to this embodiment, when the vehicle is running with the meshing clutch D1 in the meshed state during belt driving, if the vehicle driving state is within the rattling sound generation region, first, the draw torque increase control is executed. If the variation amount ΔNg exceeds the second variation amount determination value ΔNg_jdg2 during the execution of the draw torque increase control, the draw torque increase control is terminated and the nip pressure increase control is executed. The draw torque increase control suppresses deterioration of fuel consumption more than the nip pressure increase control. Therefore, compared with the case where only the nip pressure increase control is executed, the draw torque increase control is executed to suppress the rattling sound while suppressing deterioration of fuel consumption.

[0027] Note that the above is an embodiment of the present invention, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art without departing from the spirit thereof.

[0028] In the foregoing embodiment, the nip pressure increasing control is executed after the draw torque increasing control. However, if the vehicle operating state is outside the rattling sound generation region only by executing the draw torque increasing control, the nip pressure increasing control may not be executed. In the foregoing embodiment, during the execution of the nip pressure increasing control, the draw torque increasing control is not executed. However, the present invention is not limited to this. For example, the draw torque increasing control may be simultaneously executed during the execution of the nip pressure increasing control. Compared with the case where only the nip pressure increasing control is executed, when the nip pressure increasing control and the draw torque increasing control are simultaneously executed, an increase in the belt nip pressure Cp can be suppressed, so that the rattling sound is suppressed while the deterioration of fuel consumption is suppressed. Thus, in the present invention, when the vehicle is traveling with the meshing clutch D1 in the engaged state during belt running, if the vehicle operating state is within the rattling sound generation region, at least the draw torque increasing control of the draw torque increasing control and the nip pressure increasing control may be executed.

Explanation of Signs

[0029] 16: Power transmission device (vehicle power transmission device), 20: Input shaft, 26: Gear mechanism (speed reduction gear mechanism), 30: Output shaft, 50: Belt-type continuously variable transmission, 90: Electronic control device (control device), C1: First clutch (friction clutch), Cp: Belt nip pressure, D1: Meshing clutch, PT1: First power transmission path, PT2: Second power transmission path, Tt: Draw torque

Claims

[Claim 1] A control device for a power transmission device for a vehicle, the control device comprising a first power transmission path that transmits power via a belt-type continuously variable transmission and a second power transmission path that transmits power via a reduction gear mechanism, which are arranged in parallel between an input shaft and an output shaft, and a friction clutch and a dog clutch are provided in the second power transmission path in this order from the input shaft side, When the vehicle is traveling with power transmitted through the first power transmission path and the mesh clutch in an engaged state, if the vehicle operating state is in a predetermined operating range in which rattling noise occurs in the mesh clutch, at least one of a drag torque increase control for increasing the drag torque of the friction clutch and a clamping pressure increase control for increasing the belt clamping pressure of the belt-type continuously variable transmission is executed. A control device for a vehicle power transmission device comprising:

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