JP6414151B2 - Control device for belt type continuously variable transmission - Google Patents

Description

  The present invention relates to a control device for a belt-type continuously variable transmission, and more particularly to a reduction in NV level.

  A belt-type continuously variable transmission that includes a primary pulley, a secondary pulley, and a transmission belt wound around the primary pulley and the secondary pulley is well known. This is the continuously variable transmission described in Patent Document 1. In Patent Document 1, when there is a possibility of belt slippage of the continuously variable transmission, by temporarily increasing the hydraulic pressure supplied to the hydraulic actuator that adjusts the belt clamping pressure of the pulley of the continuously variable transmission, It is described that the belt clamping pressure is increased to suppress belt slip. Further, it is described that, when the supply hydraulic pressure is reduced to the normal hydraulic pressure after the supply hydraulic pressure is increased, the pressure reduction speed of the supply hydraulic pressure is decreased as the gear ratio of the continuously variable transmission increases.

JP-A-11-44359

  As described above, in the continuously variable transmission of Patent Document 1, when there is a possibility of belt slippage in the continuously variable transmission, the hydraulic pressure supplied to the hydraulic actuator is temporarily increased to clamp the belt. The belt slip was suppressed by increasing the pressure. The degree of pressure increase of the supply hydraulic pressure is obtained in advance by experiments and analysis, but is set to an excessive hydraulic pressure as much as a safety allowance is given in consideration of vehicle variations and the like. As a result, excessive hydraulic pressure is supplied to the hydraulic actuator in order to suppress the belt slip, and there is a concern that the fuel consumption is deteriorated accordingly.

  The present invention has been made against the background of the above circumstances, and its purpose is to suppress deterioration of fuel consumption while reducing vehicle vibration and noise caused by belt slip of a belt-type continuously variable transmission. It is to provide a control device that can be used.

The gist of the first invention is that a belt-type continuously variable transmission comprising (a) a primary pulley, a secondary pulley, and a transmission belt wound around the primary pulley and the secondary pulley, (B) a slip speed calculating unit that calculates a belt slip speed of the transmission belt, and (c) when the slip speed is within a predetermined range, the transmission is deviated from the predetermined range. A control unit that feedback-controls the belt clamping pressure of the belt , and (d) the predetermined range is set in advance between a lower limit value greater than zero and an upper limit value greater than the lower limit value. (E) when the slip speed is in the predetermined range, the control unit sets the slip speed to be equal to or higher than the upper limit value according to the traveling state of the vehicle or the slip speed. Said speed Characterized by the following limit values.

The gist of the second invention is the control device for the belt-type continuously variable transmission according to the first invention , wherein the control unit is configured such that the slip speed is within the predetermined range, When the difference between the speed and the upper limit value is smaller than the difference between the slip speed and the lower limit value, the slip speed is set to be equal to or higher than the upper limit value.

The gist of the third aspect of the invention is the control device for the belt-type continuously variable transmission according to the first aspect of the invention , wherein the control unit is a case where the slip speed is within the predetermined range, When it is estimated that the time required to reach the upper limit value from the slip speed is shorter than the time required to reach the lower limit value from the current slip speed, the slip speed is set to the upper limit value or more. It is characterized by that.

Further, it is an gist of the fourth invention, in the control device of any one of the belt-type continuously variable transmission of the first through third aspects of the present invention, the slipping velocity in the case of less than the lower limit, the secondary A learning control unit is provided for reducing the lower limit value when the rotational fluctuation of the pulley is larger than a predetermined value set in advance.

A fifth aspect of the present invention is the control device for a belt type continuously variable transmission according to any one of the first to fourth aspects, wherein a torque capacity is set between the secondary pulley and the drive wheel. A changeable clutch is provided, and the control unit slides the clutch when the sliding speed is in the predetermined range.

The sixth aspect of the present invention is the control device for the belt-type continuously variable transmission according to the first aspect , wherein the lower limit value is a value at which the rotational fluctuation of the secondary pulley is not more than a predetermined value set in advance. It is characterized by being set to.

The seventh aspect of the present invention is the control device for the belt type continuously variable transmission according to the first aspect , wherein the upper limit value is a value at which a frequency of vibration generated by belt slippage deviates from a frequency range of vehicle vibration. It is characterized by being set to.

According to the control device for the belt-type continuously variable transmission of the first invention, when the slip speed is within the predetermined range, the belt clamping pressure is feedback-controlled so that the slip speed is out of the predetermined range. Of the vibrations that occur when the belt-type continuously variable transmission is driven, the self-excited vibration that occurs between the belt and the pulley not only increases the belt clamping pressure and decreases the slip speed, but also reduces the belt clamping pressure. It has been found that even if the slip speed is increased, the vibration mode (frequency) of the self-excited vibration is changed to reduce the vehicle vibration and noise. Therefore, by appropriately reducing the belt clamping pressure according to the running state and increasing the slipping speed, the slipping speed deviates from the predetermined range, and the vehicle vibration and noise due to self-excited vibration are reduced and unnecessary. By preventing the belt clamping pressure from increasing, fuel consumption is prevented from deteriorating. In addition, when the slip speed is in a predetermined range, the slip speed is set to be higher than the upper limit value or lower than the lower limit value according to the traveling state of the vehicle. By detaching, vehicle vibration and noise are reduced. Further, depending on the running state of the vehicle, the belt clamping pressure is reduced by making the slip speed larger than the upper limit value. Therefore, the increase in the belt clamping pressure is prevented, and the deterioration of fuel consumption is suppressed.

Further, according to the control device for the belt-type continuously variable transmission of the second invention , when the difference between the slip speed and the upper limit value is smaller than the difference between the slip speed and the lower limit value, the slip speed is equal to or higher than the upper limit value. Therefore, the sliding speed moves closer to the upper limit value and the lower limit value, and the sliding speed can be quickly removed from the predetermined range.

Further, according to the control device for the belt-type continuously variable transmission of the third invention , the slip speed moves from the current slip speed to the shorter reach time required to reach the upper limit value and the lower limit value. Can be quickly removed from the predetermined range.

Further, according to the control device for the belt-type continuously variable transmission of the fourth invention , when the slippage speed is equal to or lower than the lower limit value, and the rotational fluctuation of the secondary pulley is larger than the predetermined value, the lower limit value within the predetermined range. Becomes smaller. The self-excited vibration has a deep relationship with the rotation fluctuation of the secondary pulley, and the self-excited vibration tends to increase as the rotation fluctuation of the secondary pulley increases. In addition, the characteristics of the self-excited vibration change due to individual differences and time-dependent changes for each vehicle. Therefore, when the rotational speed of the secondary pulley is larger than the predetermined value even though the sliding speed is equal to or lower than the lower limit value, the lower limit value is decreased and the sliding speed is controlled to be equal to or lower than the new lower limit value. As a result, it is possible to prevent vehicle vibration and noise from increasing due to individual differences and changes over time.

Further, according to the control device for the belt type continuously variable transmission of the fifth invention , when the slip speed is within a predetermined range, the slip speed is removed from the predetermined range and the clutch is slid. The amount of self-excited vibration transmitted to the drive wheels is reduced, and vehicle vibration and noise caused by the self-excited vibration can be further reduced.

Further, according to the control device for the belt-type continuously variable transmission of the sixth invention , the lower limit value is set to a value at which the rotational fluctuation of the secondary pulley is equal to or less than a predetermined value set in advance. By controlling to the lower limit value or less, self-excited vibration is reduced, and vehicle vibration and noise due to the self-excited vibration are reduced.

Further, according to the control device for the belt type continuously variable transmission of the seventh invention , since the upper limit value is set to a value where the frequency of the vibration generated by the belt slippage is out of the frequency range of the vehicle vibration, Is controlled to be equal to or higher than the upper limit value, the frequency of vibration generated by belt slippage deviates from the frequency range of vehicle vibration. Accordingly, the vehicle vibration does not increase due to the self-excited vibration due to the belt slip, so that the vehicle vibration and noise are reduced.

It is a figure explaining the schematic structure of the vehicle to which the present invention was applied. It is a figure for demonstrating the switch of the running pattern using the engagement table of the engagement element for every running pattern of the power transmission device of FIG. It is a figure explaining the principal part of the control function and various control systems for various control in the vehicle of FIG. It is a determination map for determining whether the gear ratio of the continuously variable transmission is a maximum gear ratio or a gear ratio other than the maximum gear ratio. It is a slip speed determination map used for determining whether or not the slip speed is outside a predetermined range. FIG. 4 is a flowchart for explaining a main part of the control operation of the electronic control device of FIG. 3, specifically, a control operation for suppressing vehicle vibration and noise caused by self-excited vibration generated during CVT traveling. It is a flowchart explaining the control action of the electronic controller which is another Example of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios, shapes, and the like of the respective parts are not necessarily drawn accurately.

  FIG. 1 is a diagram illustrating a schematic configuration of a vehicle 10 to which the present invention is applied. In FIG. 1, a vehicle 10 includes an engine 12 that functions as a driving force source for traveling, drive wheels 14, and a power transmission device 16 provided between the engine 12 and the drive wheels 14. The power transmission device 16 is provided integrally with a turbine shaft that is a known torque converter 20 as a fluid transmission device coupled to the engine 12 and an output rotation member of the torque converter 20 in a housing 18 as a non-rotating member. Input belt 22, a known belt-type continuously variable transmission 24 (hereinafter, continuously variable transmission 24) as a continuously variable transmission mechanism connected to the input shaft 22, and a forward / reverse switching device connected to the input shaft 22. 26, a gear mechanism 28 as a transmission mechanism connected to the input shaft 22 through the forward / reverse switching device 26 and provided in parallel with the continuously variable transmission 24, a common output rotation of the continuously variable transmission 24 and the gear mechanism 28. The output shaft 30, the counter shaft 32, and the output shaft 30 and the counter shaft 32, each of which is a member, are provided so as not to rotate relative to each other. Differential gear 38 connected to a gear 36 relatively unrotatably provided motor shaft 32, and includes an axle 40 or the like of the pair coupled to a differential gear 38. In the power transmission device 16 configured as described above, the power of the engine 12 (the torque and the force are synonymous unless otherwise distinguished) is transmitted from the torque converter 20, the continuously variable transmission 24 (or the forward / reverse switching device 26 and the gear mechanism 28). ), The reduction gear device 34, the differential gear 38, the axle 40, and the like are sequentially transmitted to the pair of drive wheels 14.

  As described above, the power transmission device 16 transmits the power of the engine 12 to the engine 12 (here, the input shaft 22 which is an input rotating member to which the power of the engine 12 is transmitted) and the driving wheel 14 (here, the driving wheel 14 is transmitted). A continuously variable transmission 24 and a gear mechanism 28 are provided in parallel with the power transmission path between the output rotating member 30 and the output shaft 30 which is the output rotating member. Therefore, the power transmission device 16 transmits the power of the engine 12 from the input shaft 22 to the drive wheel 14 side (that is, the output shaft 30) via the continuously variable transmission 24, and the power of the engine 12. A second power transmission path for transmitting from the input shaft 22 to the drive wheel 14 side (that is, the output shaft 30) via the gear mechanism 28, and depending on the traveling state of the vehicle 10, the first power transmission path and the second power transmission path. The power transmission path is configured to be switched. Therefore, the power transmission device 16 serves as a clutch mechanism that selectively switches between the first power transmission path and the second power transmission path, and performs CVT traveling as a clutch mechanism that intermittently transmits power in the first power transmission path. And a forward clutch C1 and a reverse brake B1 as a clutch mechanism for intermittently transmitting power in the second power transmission path. The CVT travel clutch C2, the forward clutch C1, and the reverse brake B1 correspond to a connection / disconnection device, and are all known hydraulic friction engagement devices (friction clutches) that are frictionally engaged by a hydraulic actuator. It is. Further, the forward clutch C1 and the reverse brake B1 are each one of elements constituting the forward / reverse switching device 26, as will be described later.

  The forward / reverse switching device 26 is provided around the input shaft 22 and coaxially with the input shaft 22 and mainly includes a double pinion planetary gear device 26p, a forward clutch C1, and a reverse brake B1. Has been. The carrier 26c of the planetary gear unit 26p is integrally connected to the input shaft 22, the ring gear 26r of the planetary gear unit 26p is selectively connected to the housing 18 via the reverse brake B1, and the sun gear 26s of the planetary gear unit 26p is A small-diameter gear 42 is provided around the input shaft 22 so as to be rotatable relative to the input shaft 22 coaxially. Further, the carrier 26c and the sun gear 26s are selectively coupled via the forward clutch C1. In the forward / reverse switching device 26 configured as described above, when the forward clutch C1 is engaged and the reverse brake B1 is released, the input shaft 22 is directly connected to the small-diameter gear 42, and the second power transmission path. The forward power transmission path is established (achieved) at. When the reverse brake B1 is engaged and the forward clutch C1 is released, the small-diameter gear 42 is rotated in the reverse direction with respect to the input shaft 22, and reverse power transmission is performed in the second power transmission path. A route is established. When both the forward clutch C1 and the reverse brake B1 are released, the second power transmission path is set to a neutral state (power transmission cutoff state) in which power transmission is interrupted.

  The gear mechanism 28 includes a small-diameter gear 42 and a large-diameter gear 46 that is provided on the gear mechanism counter shaft 44 so as not to rotate relative to the small-diameter gear 42. Therefore, the gear mechanism 28 is a transmission mechanism in which one gear stage (gear ratio) is formed. An idler gear 48 is provided around the gear mechanism counter shaft 44 so as to be rotatable relative to the gear mechanism counter shaft 44 coaxially. Around the gear mechanism counter shaft 44, a meshing clutch D <b> 1 is provided between the gear mechanism counter shaft 44 and the idler gear 48 to selectively connect and disconnect between them. Therefore, the meshing clutch D1 functions as a clutch mechanism provided in the power transmission device 16 for intermittently transmitting power in the second power transmission path. Specifically, the meshing clutch D1 is fitted to the first gear 50 formed on the gear mechanism counter shaft 44, the second gear 52 formed on the idler gear 48, and the first gear 50 and the second gear 52. And a hub sleeve 54 formed with inner peripheral teeth that can be engaged (engageable and meshable). In the meshing clutch D <b> 1 configured as described above, the gear mechanism counter shaft 44 and the idler gear 48 are connected by the hub sleeve 54 being engaged with the first gear 50 and the second gear 52. The meshing clutch D1 further includes a known synchromesh mechanism S1 as a synchronization mechanism that synchronizes rotation when the first gear 50 and the second gear 52 are engaged. The idler gear 48 meshes with an output gear 56 having a larger diameter than the idler gear 48. The output gear 56 is provided around the same rotational axis as the output shaft 30 so as not to rotate relative to the output shaft 30. When one of the forward clutch C1 and the reverse brake B1 is engaged and the meshing clutch D1 is engaged, the power of the engine 12 is transferred from the input shaft 22 to the forward / reverse switching device 26, the gear mechanism 28, the idler gear 48, and A second power transmission path that is sequentially transmitted to the output shaft 30 via the output gear 56 is established (connected).

  The continuously variable transmission 24 is provided on a power transmission path between the input shaft 22 and the output shaft 30. The continuously variable transmission 24 includes a primary pulley 58 having a variable effective diameter provided on the input shaft 22, a secondary pulley 62 having a variable effective diameter provided on a rotary shaft 60 coaxial with the output shaft 30, and a pair thereof. And a transmission belt 64 wound between the variable pulleys 58 and 62, and a power transmission is performed through a frictional force between the pair of variable pulleys 58 and 62 and the transmission belt 64. This is a push type continuously variable transmission.

  The primary pulley 58 is provided with a fixed sheave 58a as an input-side fixed rotating body that is coaxially attached to the input shaft 22, and is relatively non-rotatable around the axis and movable in the axial direction with respect to the input shaft 22. A primary side hydraulic actuator 58c (hereinafter referred to as a hydraulic actuator 58c) that generates a movable sheave 58b as an input side movable rotating body and a thrust for moving the movable sheave 58b to change the V groove width therebetween. And has.

  The secondary pulley 62 includes a fixed sheave 62a serving as an output-side fixed rotating body, and a movable sheave 62b serving as an output-side movable rotating body provided so as not to rotate around the axis and move in the axial direction with respect to the fixed sheave 62a. And a secondary hydraulic actuator 62c (hereinafter referred to as a hydraulic actuator 62c) that generates a thrust force for moving the movable sheave 62b in order to change the V groove width therebetween.

  In the continuously variable transmission 24, the V groove width of the pair of variable pulleys 58 and 62 is changed to change the engagement diameter (effective diameter) of the transmission belt 64, whereby the transmission ratio (gear ratio) γ (= input shaft). The rotational speed Nin / output shaft rotational speed Nout) is continuously changed. For example, when the V groove width of the primary pulley 58 is reduced, the gear ratio γ is reduced (that is, the continuously variable transmission 24 is upshifted). Further, when the V groove width of the primary pulley 58 is increased, the gear ratio γ is increased (that is, the continuously variable transmission 24 is downshifted). The output shaft 30 is disposed around the rotation shaft 60 so as to be rotatable relative to the rotation shaft 60 coaxially. The CVT travel clutch C2 is provided closer to the drive wheel 14 than the continuously variable transmission 24 (that is, provided between the secondary pulley 62 and the drive wheel 14 (output shaft 30)), and the secondary pulley 62. And the output shaft 30 (drive wheel 14) are selectively connected and disconnected. When the CVT travel clutch C2 is engaged, a first power transmission path is established (connected) in which the power of the engine 12 is transmitted from the input shaft 22 to the output shaft 30 via the continuously variable transmission 24. It is done.

  The operation of the power transmission device 16 will be described below. FIG. 2 is a diagram for explaining the switching of the travel pattern using the engagement table of the engagement elements for each travel pattern of the power transmission device 16. In FIG. 2, C1 corresponds to the operating state of the forward clutch C1, C2 corresponds to the operating state of the CVT traveling clutch C2, B1 corresponds to the operating state of the reverse brake B1, and D1 is the meshing clutch D1. "○" indicates engagement (connection), and "x" indicates release (cutoff).

  First, gear traveling, which is a traveling pattern in which the power of the engine 12 is transmitted to the output shaft 30 via the gear mechanism 28 (that is, a traveling pattern in which power is transmitted through the second power transmission path) will be described. In this gear travel, as shown in FIG. 2, for example, the forward clutch C1 and the meshing clutch D1 are engaged, while the CVT travel clutch C2 and the reverse brake B1 are released.

  Specifically, when the forward clutch C1 is engaged, the planetary gear device 26p constituting the forward / reverse switching device 26 is integrally rotated, so that the small-diameter gear 42 is rotated at the same rotational speed as the input shaft 22. . Further, since the small-diameter gear 42 is meshed with the large-diameter gear 46 provided on the gear mechanism counter shaft 44, the gear mechanism counter shaft 44 is similarly rotated. Further, since the meshing clutch D1 is engaged, the gear mechanism counter shaft 44 and the idler gear 48 are connected. Since the idler gear 48 is meshed with the output gear 56, the output shaft 30 provided integrally with the output gear 56 is rotated. Thus, when the forward clutch C1 and the meshing clutch D1 are engaged, the power of the engine 12 is output to the output shaft through the torque converter 20, the forward / reverse switching device 26, the gear mechanism 28, the idler gear 48, and the like in order. 30. In this gear travel, for example, when the reverse brake B1 and the meshing clutch D1 are engaged, the reverse travel is enabled when the CVT travel clutch C2 and the forward clutch C1 are released.

  Next, CVT traveling, which is a traveling pattern in which the power of the engine 12 is transmitted to the output shaft 30 via the continuously variable transmission 24 (that is, a traveling pattern in which power is transmitted through the first power transmission path) will be described. In this CVT travel, as shown in CVT travel (high vehicle speed) in FIG. 2, for example, the CVT travel clutch C2 is engaged, while the forward clutch C1, the reverse brake B1, and the meshing clutch D1 are released. The

  Specifically, when the CVT travel clutch C2 is engaged, the secondary pulley 62 and the output shaft 30 are connected, so that the secondary pulley 62 and the output shaft 30 are integrally rotated. As described above, when the CVT traveling clutch C2 is engaged, the power of the engine 12 is transmitted to the output shaft 30 via the torque converter 20, the continuously variable transmission 24, and the like sequentially. The release of the meshing clutch D1 during the CVT traveling (high vehicle speed) eliminates dragging of the gear mechanism 28 during CVT traveling, for example, and prevents the gear mechanism 28 and the like from rotating at a high vehicle speed. It is to do.

  The gear traveling is selected in a low vehicle speed region including, for example, when the vehicle is stopped. The gear ratio γ1 (that is, the gear ratio EL formed by the gear mechanism 28) in the second power transmission path is the maximum gear ratio formed by the continuously variable transmission 24 (that is, the lowest gear that is the lowest gear speed side gear ratio). Ratio) is set to a value larger than γmax (that is, the gear ratio on the low side). For example, the gear ratio γ1 corresponds to the first speed gear ratio γ1 that is the gear ratio of the first speed gear stage in the power transmission device 16, and the lowest gear ratio γmax of the continuously variable transmission 24 is the second gear ratio γmax in the power transmission device 16. This corresponds to the second speed gear ratio γ2 that is the gear ratio of the speed gear stage. Therefore, for example, gear traveling and CVT traveling are switched according to a shift line for switching between the first speed gear stage and the second speed gear stage in a known shift map of a stepped transmission. For example, in CVT traveling, a known method is used to perform a shift (for example, a CVT shift or a continuously variable shift) in which the gear ratio γ is changed based on the travel state such as the accelerator opening θacc and the vehicle speed V. . Here, when switching from gear travel to CVT travel (high vehicle speed), or from CVT travel (high vehicle speed) to gear travel, as shown in FIG. 2, the CVT travel (medium vehicle speed) is switched via a transition. It is done.

  For example, when switching from gear traveling to CVT traveling (high vehicle speed), the CVT traveling clutch C2 and the meshing clutch D1 are engaged from the state in which the forward clutch C1 and the meshing clutch D1 corresponding to the gear traveling are engaged. The vehicle is transitively switched to the CVT traveling (medium vehicle speed) that has been performed. That is, a shift (for example, clutch-to-clutch shift (hereinafter referred to as CtoC shift)) is performed in which the forward clutch C1 is released and the CVT travel clutch C2 is engaged. At this time, the power transmission path is changed from the second power transmission path to the first power transmission path, and the power transmission device 16 is substantially upshifted. Then, after the power transmission path is switched, the meshing clutch D1 is released to prevent unnecessary dragging and high rotation of the gear mechanism 28 and the like (see driven input cutoff in FIG. 2). In this way, the meshing clutch D1 functions as a driven input cutoff clutch that blocks input from the drive wheel 14 side.

  Further, for example, when switching from CVT travel (high vehicle speed) to gear travel, the meshing clutch D1 is further engaged in preparation for switching from gear CVT travel clutch C2 to gear travel. The vehicle is transiently switched to CVT running (medium vehicle speed) (see the downshift preparation in FIG. 2). In this CVT traveling (medium vehicle speed), the rotation is transmitted to the sun gear 26s of the planetary gear unit 26p via the gear mechanism 28. When a shift (for example, CtoC shift) is executed to release the CVT travel clutch C2 and engage the forward clutch C1 from this CVT travel (medium vehicle speed) state, the operation is switched to gear travel. . At this time, the power transmission path is changed from the first power transmission path to the second power transmission path, and the power transmission device 16 is substantially downshifted.

  FIG. 3 is a diagram for explaining the main functions of the control function and control system for various controls in the vehicle 10. In FIG. 3, the vehicle 10 is provided with an electronic control device 80 including a control device for the vehicle 10 that switches the traveling pattern of the power transmission device 16, for example. Therefore, FIG. 3 is a diagram showing an input / output system of the electronic control device 80, and is a functional block diagram for explaining a main part of a control function by the electronic control device 80. The electronic control unit 80 includes, for example, a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like, and the CPU uses a temporary storage function of the RAM according to a program stored in the ROM in advance. Various controls of the vehicle 10 are executed by performing signal processing. For example, the electronic control unit 80 executes output control of the engine 12, shift control of the continuously variable transmission 24, belt clamping pressure control, switching control for switching the traveling pattern to CVT traveling or gear traveling, and the like. It is configured separately for engine control, shift control, etc. as required.

  The electronic control device 80 includes various sensors (for example, an engine rotation speed sensor 82, an input shaft rotation speed sensor 84, an output shaft rotation speed sensor 86, an accelerator opening sensor 88, a throttle valve opening sensor 90, a foot brake). Various actual values (for example, an engine rotation speed Ne, an input shaft rotation speed Nin that is a rotation speed of the primary pulley 58 corresponding to the turbine rotation speed Nt, The output shaft rotation speed Nout, which is the rotation speed of the secondary pulley 62 corresponding to the vehicle speed V, the accelerator pedal operation amount θacc, the throttle valve opening θth, which is the driver's requested acceleration amount, and the foot that is the service brake Brake on Bon which is a signal indicating a state in which the brake is operated, longitudinal acceleration G of the vehicle 10, Primary pressure Pin is supplied to the hydraulic actuator 58c of Raimaripuri 58, such as secondary pressure Pout supplied to the hydraulic actuator 62c of the secondary pulley 62) is supplied.

  From the electronic control unit 80, an engine output control command signal Se for output control of the engine 12, a hydraulic control command signal Scvt for hydraulic control related to a shift of the continuously variable transmission 24, and a switching of a traveling pattern of the power transmission device 16 are performed. The hydraulic control command signal Sswt and the like for controlling the forward / reverse switching device 26, the CVT travel clutch C2, and the meshing clutch D1 are output. Specifically, as an engine output control command signal Se, a throttle signal for driving the throttle actuator to control the opening and closing of the electronic throttle valve, an injection signal for controlling the amount of fuel injected from the fuel injection device, An ignition timing signal or the like for controlling the ignition timing of the engine 12 by the ignition device is output. Further, as a hydraulic control command signal Sccvt, a command signal for driving a solenoid valve for adjusting the primary pressure Pin supplied to the hydraulic actuator 58c of the primary pulley 58, and a secondary pressure Pout supplied to the hydraulic actuator 62c of the secondary pulley 62. A command signal for driving a solenoid valve for adjusting the pressure is output to the hydraulic control circuit 96. Further, as a hydraulic control command signal Sswt, each solenoid valve that controls each hydraulic pressure supplied to the forward clutch C1, the reverse brake B1, the CVT travel clutch C2, the actuator that operates the hub sleeve 54, and the like is driven. A command signal or the like is output to the hydraulic control circuit 96.

  The electronic control unit 80 includes an engine output control unit 100 (engine output control unit), a shift control unit 102 (shift control unit), a slip rate calculation unit 104 (slip rate calculation unit), and a slip speed calculation unit 106 (slip speed calculation unit). ), A sliding speed determination unit 108 (sliding speed determination unit), a learning control unit 110 (learning control unit), and a rotation variation determination unit 112 (rotation variation determination unit). Note that the shift control unit 102 corresponds to the control unit of the present invention.

   The engine output control unit 100 outputs an engine output control command signal Se to, for example, a throttle actuator, a fuel injection device, and an ignition device for output control of the engine 12, for example. The engine output control unit 100 calculates a required drive output Pdem as a drive request amount by the driver based on the actual accelerator opening θacc and the vehicle speed V based on a predetermined relationship (not shown) (drive force map), for example, The target engine torque Tetgt for obtaining the required drive output Pdem is set, the electronic throttle valve is controlled to open / close by the throttle actuator so that the target engine torque Tetgt can be obtained, and the fuel injection amount is controlled by the fuel injection device. Or the ignition timing is controlled by an ignition device.

  The shift control unit 102 is a hydraulic control that controls the gear ratio γ of the continuously variable transmission 24 so that the target gear ratio γtgt calculated based on the accelerator opening θacc, the vehicle speed V, the brake signal Bon, and the like is obtained during CVT travel. Command signal Sccv is output to hydraulic control circuit 96. Specifically, the shift control unit 102 adjusts the belt clamping pressure of the continuously variable transmission 24 to an optimum value, while the operating point of the engine 12 is on a predetermined optimum line (for example, the engine optimum fuel consumption line). A predetermined relationship (for example, a CVT shift map) for achieving the target gear ratio γtgt of the step transmission 24 is stored, and is supplied to the actuator 58c based on the accelerator opening θacc and the vehicle speed V from the relationship. A primary command pressure Pintgt as a command value of the primary pressure Pin and a secondary command pressure Pouttgt as a command value of the secondary pressure Pout supplied to the hydraulic actuator 62c are determined, and the primary command pressure Pintgt and the secondary command pressure Pouttgt are hydraulically controlled. Output to circuit 96 to execute CVT shift.

  Further, the speed change control unit 102 transmits the power of the engine 12 to the output shaft 30 via the gear mechanism 28, and transmits the power of the engine 12 to the output shaft 30 via the continuously variable transmission 24. Switching control for switching between CVT running is executed. Specifically, the shift control unit 102 determines whether or not to switch a traveling pattern during traveling of the vehicle. For example, the shift control unit 102 switches the upshift line and downshift for switching between the first speed gear ratio γ1 corresponding to the gear ratio EL in gear traveling and the second speed gear ratio γ2 corresponding to the lowest gear ratio γmax in CVT traveling. Using the shift line, a shift (gear ratio switching) is determined based on the vehicle speed V and the accelerator opening θacc, and based on the determination result, it is determined whether or not to switch the traveling pattern during vehicle traveling. The upshift line and the downshift line are predetermined shift lines and have a predetermined hysteresis.

  When the shift control unit 102 determines the switching of the running pattern, the shift control unit 102 executes the switching of the running pattern. For example, the shift control unit 102 switches from gear running to CVT running (high vehicle speed) when it determines an upshift during gear running. When switching from gear travel to CVT travel (high vehicle speed), the shift control unit 102 first releases the forward clutch C1 and performs an upshift by CtoC shift that engages the CVT travel clutch C2. This state corresponds to the transiently switched CVT traveling (medium vehicle speed) in FIG. 2, and the power transmission path in the power transmission device 16 is a second power transmission path through which power is transmitted via the gear mechanism 28. To the first power transmission path through which power is transmitted via the continuously variable transmission 24. Next, the shift control unit 102 outputs a command to operate the hub sleeve 54 of the synchro mechanism S1 so as to release the engaged clutch D1 and switches to CVT running (high vehicle speed). The hub sleeve 54 is driven by a hydraulic actuator (not shown), and the pressing force to the hub sleeve 54 is adjusted by the hydraulic pressure supplied to the hydraulic actuator.

  Further, when the shift control unit 102 determines a downshift during CVT travel (high vehicle speed), the shift control unit 102 switches from CVT travel (high vehicle speed) to gear travel. When switching from CVT travel (high vehicle speed) to gear travel, the shift control unit 102 first outputs a command to operate the hub sleeve 54 of the synchro mechanism S1 to engage the disengaged meshing clutch D1. Switch to CVT running (medium vehicle speed). Next, the shift control unit 102 performs a downshift by a CtoC shift that releases the CVT travel clutch C2 and engages the forward clutch C1. This state corresponds to the gear running in FIG. 2, and the power transmission path in the power transmission device 16 is from the first power transmission path through which the power is transmitted via the continuously variable transmission 24 via the gear mechanism 28. It is switched to the second power transmission path through which power is transmitted. As described above, when the transmission control unit 102 switches from the power transmission via the continuously variable transmission 24 to the power transmission via the gear mechanism 28 while the vehicle 10 is traveling, the gear clutch D1 is set to the engagement side. After the operation, the CVT travel clutch C2 is released.

  By the way, during CVT traveling, self-excited vibration is generated due to slippage (belt slip) between each of the pulleys 58 and 62 of the continuously variable transmission 24 and the transmission belt 64, and furthermore, due to this self-excited vibration. Vehicle vibrations and noises that occur are a problem. In order to suppress this, conventionally, the self-excited vibration has been reduced by increasing the belt clamping pressure and reducing the belt slip. However, the amount of increase in the belt clamping pressure needs to be set to an excessive value from the optimum value for each vehicle in consideration of variations among vehicles, safety allowance, and the like. Accordingly, since the belt clamping pressure is constantly increased, the hydraulic pressure supplied to the hydraulic actuators 58c and 62c is also increased, and the fuel consumption is deteriorated. In addition, it is necessary to use a highly durable transmission belt, which may increase the manufacturing cost.

  In order to eliminate the above-described problems, in this embodiment, the belt clamping pressure of the continuously variable transmission 24 is controlled as described below, thereby reducing fuel consumption while suppressing vehicle vibration and noise caused by self-excited vibration. Suppress.

  The vehicle state determination unit 103 determines whether or not the vehicle is in a traveling state in which self-excited vibration becomes a problem. The self-excited vibration is not always a problem during CVT traveling, and becomes significant when the vehicle is in a predetermined traveling state. Therefore, the vehicle state determination unit 103 stores in advance a traveling state in which self-excited vibration becomes significant. When the vehicle enters the traveling state, the vehicle state determination unit 103 determines to execute control for suppressing vehicle vibration and noise, which will be described later. The traveling state in which the self-excited vibration becomes remarkable is obtained experimentally in advance, and is defined from, for example, the gear ratio γ of the continuously variable transmission 24, the input torque Tin, various rotational speeds (such as the input shaft rotational speed Nin). Has been. For example, when the vehicle state determination unit 103 detects that the gear ratio γ of the continuously variable transmission 24 is within a predetermined range in which self-excited vibration becomes significant, the vehicle state determination unit 103 determines to execute control for suppressing vehicle vibration and noise. . In this way, a running state in which self-excited vibration becomes significant is obtained in advance by experiment (or analysis), and control for suppressing vehicle vibration and noise, which will be described later, is executed only when the running state is reached. Thus, the control load applied to the electronic control unit 80 is reduced. The input torque Tin input to the continuously variable transmission 24 is calculated by the product of the engine torque Te and the torque ratio of the torque converter 14.

  When the vehicle state determination unit 103 determines to execute control for suppressing vehicle vibration and noise, the slip ratio calculation unit 104 is executed. The slip ratio calculation unit 104 calculates a slip ratio η between the pulleys 58 and 62 and the transmission belt 64 during CVT traveling.

  The slip ratio calculation unit 104 first determines whether or not the gear ratio γ of the continuously variable transmission 24 is the maximum gear ratio γmax. Whether or not the gear ratio γ is the maximum gear ratio γmax is determined using a determination map of the gear ratio γ shown in FIG. In the determination map shown in FIG. 4, the horizontal axis indicates the secondary pressure Pout of the secondary pulley 62, and the vertical axis indicates the primary pressure Pin of the primary pulley 58. The curve shown in FIG. 4 shows a boundary line between a region having the maximum gear ratio γmax and a region having a gear ratio γ other than the maximum gear ratio γmax. The right side of the boundary line indicates the maximum gear ratio. A region where γmax is shown is shown, and the left side of the boundary line shows a region where the gear ratio γ is other than the maximum gear ratio γmax. 4, the maximum gear ratio γmax is obtained in the region where the secondary pressure Pout is high, and the gear ratio γ other than the maximum gear ratio γmax is obtained in the region where the primary pressure Pin is high. Note that the determination map of FIG. 4 is obtained and stored in advance by experiment or analysis. The slip ratio calculation unit 104 determines in which region the current gear ratio γ is based on the actual primary pressure Pin and secondary pressure Pout using the determination map of FIG. 4. For example, when the slip ratio calculation unit 104 is in the region of the maximum gear ratio γmax, the gear ratio γ is determined to be the maximum gear ratio γmax, and when it is in the region of the gear ratio γ other than the maximum gear ratio γmax. The gear ratio γ is determined to be a gear ratio γ other than the maximum gear ratio γmax.

Further, when the gear ratio γ is determined to be the maximum gear ratio γmax, the slip ratio calculation unit 104 calculates the slip ratio η based on the following equation (1). The theoretical γmax is the maximum gear ratio γ that is uniquely determined based on the structure of the continuously variable transmission 24. Equation (1) shows that when the gear ratio is at the maximum gear ratio γmax, the slip ratio η is calculated from the actual input shaft rotational speed Nin and the output shaft rotational speed Nout, and the input shaft rotational speed (Nout × theoretical γmax). Is obtained by dividing the difference (Nin−Nout × theoretical γmax) by the input shaft rotational speed Nin.
η = (Nin−Nout × theoretical γmax) / Nin (1)

  In addition, when it is determined that the gear ratio γ is other than the maximum gear ratio γmax, the slip ratio calculation unit 104 presumably calculates the slip ratio η using a relational expression or a relation map obtained in advance by experiments or analysis. The relational expression or the relation map includes, for example, an input torque Tin input to the continuously variable transmission 24, a primary pressure Pin corresponding to the belt clamping pressure on the primary pulley 58 side, and a secondary corresponding to the belt clamping pressure on the secondary pulley 62 side. The pressure Pout and the gear ratio γ are configured as parameters. The input torque Tin, the primary pressure Pin, the secondary pressure Pout, and the gear ratio γ are all parameters correlated with the slip ratio η, and the slip ratio η can be estimated based on these parameters. The slip ratio calculation unit 104 predictively calculates the slip ratio η by applying the actual input torque Tin, the primary pressure Pin, the secondary pressure Pout, and the gear ratio γ to the relational expression or the relation map.

The slip speed calculation unit 106 calculates the slip speed ΔN based on the slip ratio η calculated by the slip ratio calculation 104 and the input shaft rotation speed Nin that is the rotation speed of the primary pulley 58. The sliding speed ΔN is calculated based on the following formula (2). From equation (2), it is shown that the slip speed ΔN is calculated by the product of the slip ratio η and the input shaft rotational speed Nin.
ΔN = η × Nin (2)

  The slip speed determination unit 108 determines whether or not the slip speed ΔN calculated by the slip speed calculation unit 106 is outside a predetermined range set in advance. FIG. 5 is a determination map of the sliding speed ΔN obtained in advance by experiment or analysis, which is used to determine whether or not the sliding speed ΔN is outside the predetermined range. In FIG. 5, the horizontal axis indicates the engine rotation speed Ne, and the vertical axis indicates the slip speed ΔN. “◯” shown in FIG. 5 indicates the slip speed ΔN at which the magnitude of the self-excited vibration generated between the pulleys 58 and 62 and the transmission belt 64 becomes a predetermined value or less. Whether or not the magnitude of the self-excited vibration is equal to or smaller than a predetermined value is determined when the rotational fluctuation ΔNout of the output shaft rotational speed Nout, which is the rotational speed of the secondary pulley 62, is equal to or smaller than a predetermined value β. It is determined that the magnitude of the excitation vibration is equal to or less than a predetermined value, and the predetermined value β is set to a value that does not cause the driver to feel uncomfortable due to vehicle vibration and noise generated by the self-excited vibration.

  In FIG. 5, “×” indicates that the self-excited vibration between the pulleys 58 and 62 and the transmission belt 64 is larger than a predetermined value (that is, the rotational fluctuation ΔNout of the output shaft rotational speed Nout exceeds the predetermined value β). ) The sliding speed ΔN is shown. Further, “□” shown in FIG. 5 indicates a slip speed ΔN at which the self-excited vibration does not cause a problem although the self-excited vibration is larger than a predetermined value. Here, the fact that self-excited vibration is not a problem means that the driver is not affected by vehicle vibration and noise generated due to the self-excited vibration, although the self-excited vibration is larger than a predetermined value. ing.

  Vehicle vibration is vibration generated in the steering, seat, floor, etc., and is detected by, for example, an acceleration sensor attached to the steering, seat, floor, etc., for example. Then, when the vibration detected by each sensor has not reached the specified value that affects the driver, it is determined that the vehicle vibration has no problem. In addition, the noise is detected by, for example, a microphone provided in the vehicle, and if the specified value that affects the driver is not reached, it is determined that there is no problem with the noise. Therefore, the slip speed ΔN indicated by “□” indicates that the vehicle vibration and noise do not exceed the specified value, although the self-excited vibration is larger than the predetermined value. Note that the slipping speed ΔN indicated by “x” indicates that the self-excited vibration is larger than a predetermined value, and at least one of the vehicle vibration and noise exceeds a specified value. A slip speed ΔN indicated by “◯” indicates that the self-excited vibration is smaller than a predetermined value, and the vehicle vibration and noise do not exceed the specified value.

  As shown in FIG. 5, the value of the boundary between the slipping speed ΔN at which the self-excited vibration indicated by “×” is equal to or higher than the predetermined value and the slipping speed ΔN at which the self-excited vibration indicated by “◯” is equal to or lower than the predetermined value It was confirmed that even if the engine speed Ne changes, it takes a substantially constant value. This boundary value is set as a predetermined value A (lower limit value). In other words, the predetermined value A is set to a value in which the self-excited vibration is smaller than the predetermined value (the rotational speed Nout of the secondary pulley 62 is equal to or less than the predetermined value β), and the vehicle vibration and noise do not exceed the specified values. Yes.

  On the other hand, although the self-excited vibration is equal to or greater than a predetermined value, the slip speed ΔN indicated by “□” that does not affect the vehicle vibration and noise varies with the engine speed Ne. Specifically, the slip speed ΔN indicated by “□” increases as the engine speed Ne decreases. Although the self-excited vibration indicated by “□” exceeds a predetermined value, the boundary value between the slipping speed ΔN at which vehicle vibration and noise are not a problem and the slipping speed indicated by “×” is a straight line according to the engine rotational speed Ne. It is set as a predetermined value B (upper limit value) that changes automatically. Note that the predetermined value A and the predetermined value B coincide with each other when the engine rotational speed Ne increases to a predetermined speed. A region between the predetermined value A larger than zero and the predetermined value B larger than the predetermined value A is set as a predetermined range of the slip speed ΔN.

  Here, even if the self-excited vibration becomes larger than the predetermined value in the region where the slip speed ΔN is equal to or higher than the predetermined value B, the self-excited vibration does not become a problem because the frequency of the self-excited vibration changes. . In the region where the slip speed ΔN is equal to or greater than the predetermined value B, the frequency of the self-excited vibration changes, so that the frequency falls outside the vehicle vibration and noise frequency ranges. As a result, since resonance does not occur due to self-excited vibration, vehicle vibration and noise are hardly affected by the self-excited vibration. Therefore, not only the slipping speed ΔN is set to the predetermined value A or lower, but also the vehicle vibration and noise are suppressed by setting the sliding speed ΔN to the predetermined value B or higher. Therefore, the predetermined value B is set to a value in which the frequency of self-excited vibration (vibration generated by belt slip) deviates from the frequency range of vehicle vibration.

  The slip speed determination unit 108 determines whether the current slip speed ΔN is equal to or less than the predetermined value A or equal to or greater than the predetermined value B using the determination map of the slip speed ΔN in FIG. When the slip speed ΔN is in the region of the predetermined value A or less or the predetermined value B or more, it is determined that the slip speed ΔN is outside the predetermined range. On the other hand, when the sliding speed ΔN is larger than the predetermined value A and smaller than the predetermined value B, it is determined that the sliding speed ΔN is within a predetermined range.

  When the slip speed determination unit 108 determines that the slip speed ΔN is within a predetermined range, the shift control unit 102 determines the belt clamping pressure of the transmission belt 64 (that is, the slip speed ΔN is out of the predetermined range). The primary pressure Pin and the secondary pressure Pout) are feedback controlled. That is, the belt clamping pressure is feedback-controlled so that the slip speed ΔN is equal to or less than the predetermined value A or the slip speed ΔN is equal to or greater than the predetermined value B.

  The shift control unit 102 calculates, for example, a difference L1 (= ΔN−A) between the current slip speed ΔN and the predetermined value A and a difference L2 (= B−ΔN) between the slip speed ΔN and the predetermined value B. The sliding speed ΔN is changed to the side where the difference is small. Specifically, when the difference L1 is smaller than the difference L2, the shift control unit 102 feedback-controls the belt clamping pressure so that the slip speed ΔN is equal to or less than the predetermined value A, and the difference L2 is smaller than the difference L1. If it is smaller, the belt clamping pressure is feedback-controlled so that the slip speed ΔN is equal to or higher than the predetermined value B.

  When setting the target value ΔN * of the slip speed ΔN, the shift control unit 102 performs feedback control of the belt clamping pressure so that the slip speed ΔN follows the target value ΔN *. Note that the target value ΔN * of the slipping speed ΔN is a value that takes into account the margin in advance with respect to the predetermined value (predetermined value A or predetermined value B) on the smaller difference side, taking into account vehicle variations and the like. Is set. The shift control unit 102 adds a preset gain (such as a proportional gain K) to a deviation (= ΔN * −ΔN) between the target value ΔN * and the current slip speed ΔN, Specifically, the primary command pressure Pintgt of the primary pressure Pin of the primary pulley 58 and the secondary command pressure Pouttgt of the secondary pressure Pout of the secondary pulley 62 are calculated. Then, the shift control unit 102 outputs the calculated primary command pressure Pintgt and secondary command pressure Pouttgrt to the hydraulic control circuit 96.

  For example, when the shift control unit 102 calculates the secondary command pressure Pouttgt that decreases (or increases) the slip speed ΔN as the control amount of the feedback control, the gear ratio γ of the continuously variable transmission 24 is changed with respect to the change in the secondary pressure Pout. The primary command pressure Pintgt to be maintained is calculated based on a predetermined relationship (in this case, the secondary pressure Pout is substantially feedback-controlled). By the above control, the slipping speed ΔN is out of the predetermined range, so that vehicle vibration and noise are suppressed. In particular, when the slip speed Δ is set to be equal to or higher than the predetermined value B, the belt clamping pressure applied to the transmission belt 64 is reduced, so that an increase in unnecessary belt clamping pressure is suppressed. Therefore, since the supply hydraulic pressure supplied to the hydraulic actuators 58c and 62c is lowered, deterioration of fuel consumption is also suppressed.

  In the above control, when the slip speed ΔN is within a predetermined range in which vehicle vibration and noise are problems, the slip speed ΔN and the predetermined value A and the predetermined value B are shifted to the side where the differences L1 and L2 are smaller. ΔN was moved. However, as long as the slipping speed ΔN is excluded from the predetermined range, the sliding speed ΔN is not limited to the smaller side of the differences L1 and L2. For example, it may be one that moves to the side where the arrival time required to deviate the sliding speed ΔN from a predetermined range is short. Specifically, an arrival time T1 required for the current slip speed ΔN to reach the predetermined value A and an arrival time T2 required for the slip speed ΔN to reach the predetermined value B are respectively determined by experiment or analysis. The slip speed ΔN is moved to the shorter side of the arrival times T1 and T2. For example, when the arrival time T1 until the predetermined value A is reached from the current slip speed ΔN is shorter than the arrival time T2 until the predetermined value B is reached, the slip speed ΔN is controlled to be equal to or less than the predetermined value A. . When the arrival time T2 is shorter than the arrival time T1, the slip speed ΔN is controlled to be equal to or greater than the predetermined value B. The arrival times T1 and T2 are experimentally obtained under various conditions using the input torque Tin, the gear ratio γ, the oil temperature and the like as parameters.

  By the way, although the predetermined value A and the predetermined value B are set as initial values obtained in advance, the optimum values vary depending on individual differences of vehicles and aging. On the other hand, the learning control unit 110 determines the vehicle vibration and the noise based on the rotational fluctuation ΔNout of the secondary sheave 62 that is closely related to the self-excited vibration so that the vehicle vibration and noise are suppressed regardless of the individual difference and the secular change of the vehicle. The learning control of the value A is executed.

  The rotation fluctuation determination unit 112 is a case where the slip speed determination unit 108 determines that the slip speed ΔN is out of the predetermined range, and particularly when the slip speed ΔN is equal to or less than the predetermined value A, the secondary pulley Based on the rotational speed of 62, that is, the output shaft rotational speed Nout, the rotational fluctuation ΔNout of the output shaft rotational speed Nout is calculated, and it is determined whether or not the calculated rotational fluctuation ΔNout is equal to or less than a preset predetermined value β. . The rotation fluctuation ΔNout is a change amount of the output shaft rotation speed Nout per unit time, and is calculated by differentiating the output shaft rotation speed Nout detected at any time with time.

  The learning control unit 110 decreases the predetermined value A when the rotation variation determination unit 112 determines that the rotation variation ΔNout of the secondary pulley 62 is greater than the predetermined value β. For example, when it is determined that the rotational fluctuation ΔNout is larger than the predetermined value β when the slip speed ΔN is equal to or less than the predetermined value A, the learning control unit 110 learns the current slip speed ΔN as a new predetermined value A. As a result, the predetermined value A is updated to a value smaller than the predetermined value A before learning. When the predetermined value A is updated by the learning control unit 110, the shift control unit 102 performs feedback control of the belt clamping pressure so that the slip speed ΔN becomes smaller than the updated predetermined value A. Therefore, self-excited vibration is suppressed regardless of individual differences and aging of vehicles.

  FIG. 6 is a flowchart for explaining a main part of the control operation of the electronic control unit 80, specifically, a control operation for suppressing vehicle vibration and noise caused by self-excited vibration generated during CVT traveling. This flowchart is repeatedly executed during CVT traveling.

  First, in step S1 (hereinafter, step is omitted) corresponding to the function of the vehicle state determination unit 103, the traveling state of the vehicle is set by the gear ratio γ, the input torque Tin, various rotational speeds, and the like. It is determined whether or not the vehicle is in a traveling state in which is prominent. If it is determined that the running state is not such that the self-excited vibration is significant, S1 is denied and the present routine is terminated. When it is determined that the traveling state is prominent in self-excited vibration, S1 is affirmed and the process proceeds to S2.

  In step S2 corresponding to the function of the slip ratio calculation unit 104, it is determined whether or not the gear ratio γ of the continuously variable transmission 24 is the maximum gear ratio γmax based on the primary pressure Pin and the secondary pressure Pout. When it is determined that the gear ratio γ is not the maximum gear ratio γmax, S2 is denied and the process proceeds to S3. In S3 corresponding to the function of the slip ratio calculation unit 104, the slip ratio η is estimated based on a relational expression or relation map composed of the input torque Tin, belt clamping pressure (primary pressure Pin, secondary pressure Pout), and gear ratio γ. Is calculated automatically. On the other hand, when it is determined in S2 that the gear ratio γ is the maximum gear ratio γmax, S2 is affirmed and the process proceeds to S4. In S4 corresponding to the function of the slip calculation unit 104, the slip ratio η is calculated based on the above-described equation (1).

  In S5 corresponding to the function of the slip speed calculation unit 106, the slip speed ΔN is calculated by multiplying the slip rate η calculated in S2 or S3 by the input shaft rotational speed Nin. In S6 corresponding to the function of the slip speed determination unit 108, it is determined whether or not the calculated slip speed ΔN is equal to or less than a predetermined value A or a predetermined value B. If the slip speed ΔN is larger than the predetermined value A and smaller than the predetermined value B, S6 is denied and the process proceeds to S9. In S9 corresponding to the speed change control unit 102, the target value ΔN * of the slip speed ΔN is set, and the belt clamping pressure (primary pressure Pin, secondary pressure Pout) is set so that the slip speed ΔN follows the target value ΔN *. Feedback control is executed. Therefore, the control of S2 to S6 and S9 is repeatedly executed until the slip speed ΔN becomes equal to or less than the predetermined value A or equal to or higher than the predetermined value B.

  In S6, when it is determined that the slip speed ΔN is equal to or less than the predetermined value A or equal to or greater than the predetermined value B, S6 is affirmed and the process proceeds to S7. In S7 corresponding to the function of the rotation fluctuation determination unit 112, the rotation fluctuation ΔNout of the secondary pulley 62 is calculated. Next, in S8 corresponding to the rotation fluctuation determination unit 112, it is determined whether or not the rotation fluctuation ΔNout calculated in S7 is equal to or less than a predetermined value β. When the rotational fluctuation ΔNout is larger than the predetermined value β, S8 is denied and the process proceeds to S10. In S10 corresponding to the function of the learning control unit 110, when the slip speed ΔN is equal to or less than the predetermined value A, the current slip speed ΔN is updated (set) as a new predetermined value A. That is, the predetermined value A is changed to a lower side. Then, returning to S6, it is determined again whether or not the slip speed ΔN is equal to or lower than the predetermined value A or higher than the predetermined value B. Returning to S8, when the rotational fluctuation ΔNout is equal to or smaller than the predetermined value β, this routine is terminated.

  As described above, according to this embodiment, when the slip speed ΔN is within a predetermined range, the belt clamping pressure is feedback-controlled so that the slip speed ΔN is out of the predetermined range. Of the vibrations that occur during the driving of the continuously variable transmission 24, the self-excited vibrations that occur between the transmission belt 46 and the pulleys 58 and 62 not only increase the belt clamping pressure and reduce the slip speed ΔN, It has been found that even if the belt clamping pressure is decreased and the slip speed ΔN is increased, the vibration mode (frequency) of self-excited vibration is changed to reduce vehicle vibration and noise. Therefore, by appropriately reducing the belt clamping pressure according to the running state and increasing the slipping speed ΔN, the slipping speed ΔN is out of a predetermined range, and vehicle vibration and noise due to self-excited vibration are reduced. By preventing an unnecessary increase in the belt clamping pressure, deterioration of fuel consumption is suppressed.

  Further, according to the present embodiment, when the slip speed ΔN is in a predetermined range, the slip speed ΔN is made larger than the predetermined value B or smaller than the predetermined value A depending on the traveling state of the vehicle. Therefore, the slip speed ΔN is out of the predetermined range. Accordingly, vehicle vibration and noise are reduced. Further, depending on the running state of the vehicle, the belt clamping pressure is reduced by making the slip speed ΔN larger than the predetermined value B, so that an increase in the belt clamping pressure is prevented and deterioration of fuel consumption is suppressed.

  Further, according to the present embodiment, when the difference L2 between the sliding speed ΔN and the predetermined value B is smaller than the difference L1 between the sliding speed ΔN and the predetermined value A, the sliding speed ΔN is set to be equal to or higher than the predetermined value B. Therefore, the sliding speed ΔN moves to the closer side between the predetermined value A and the predetermined value B, and the sliding speed ΔN can be quickly removed from the predetermined range.

  Further, according to the present embodiment, the slip speed ΔN can also be obtained by moving the slip speed ΔN to the shorter side of the arrival times T1 and T2 required to reach the predetermined value A and the predetermined value B from the current slip speed ΔN. Can be quickly removed from the predetermined range.

  Further, according to the present embodiment, when the sliding speed ΔN is equal to or less than the predetermined value A, the predetermined value A becomes smaller when the rotational fluctuation ΔNout of the secondary pulley 62 is larger than the predetermined value β. The self-excited vibration has a deep relationship with the rotational fluctuation ΔNout of the secondary pulley 62, and the self-excited vibration tends to increase as the rotational fluctuation ΔNout of the secondary pulley 58 increases. In addition, the characteristics of the self-excited vibration change due to individual differences and time-dependent changes for each vehicle. Therefore, when the rotational fluctuation ΔNout of the secondary pulley 62 is larger than the predetermined value β even though the sliding speed ΔN is equal to or less than the predetermined value A, the predetermined value A is decreased and the sliding speed ΔN is set to a new predetermined value A. By controlling to be as follows, vehicle vibration and noise are prevented from increasing due to individual differences and time-dependent changes for each vehicle.

  Further, according to the present embodiment, the predetermined value A is set to a value at which the rotation fluctuation ΔNout of the secondary pulley 62 is equal to or less than a predetermined value β, so that the slip speed ΔN is equal to or less than the predetermined value A. By being controlled, the self-excited vibration is reduced, and the vehicle vibration and noise caused by the self-excited vibration are reduced.

  Further, according to the present embodiment, the predetermined value B is set such that the frequency of self-excited vibration generated by belt slippage is set to a value that deviates from the frequency range of vehicle vibration. By being controlled, the frequency of the self-excited vibration generated by the belt slip is out of the frequency range of the vehicle vibration. Accordingly, the vehicle vibration does not increase due to the self-excited vibration due to the belt slip, so that the vehicle vibration and noise are reduced.

  Next, another embodiment of the present invention will be described. In the following description, parts common to the above-described embodiments are denoted by the same reference numerals and description thereof is omitted.

  In the above-described embodiment, when the slipping speed ΔN is larger than the predetermined value A and smaller than the predetermined value B, the belt clamping pressure is set so that the slipping speed ΔN is not more than the predetermined value A or not less than the predetermined value B. In other words, feedback control is performed on the primary pressure Pin and the secondary pressure Pout. However, while the slip speed ΔN is within the predetermined range, the self-excited vibration is transmitted to the drive wheels 14, and vehicle vibration and noise are generated. Therefore, in this embodiment, the torque capacity provided between the continuously variable transmission 24 and the drive wheels 14 is changed in conjunction with the feedback control of the belt clamping pressure while the slip speed ΔN is in a predetermined range. By sliding the possible CVT travel clutch C2, the amount of vibration (self-excited vibration) transmitted to the drive wheels 14 is reduced. The shift control unit 102 ′ (see FIG. 3) of the present embodiment sets the CVT travel clutch C2 in advance until the slip speed ΔN reaches the target value ΔN * in conjunction with the feedback control of the belt clamping pressure. Slide only the target slip amount SLIP *. The target slip amount SLIP * is obtained in advance by experiment or analysis, and the vibration transmitted to the drive wheels 14 is reduced, so that the driver feels uncomfortable due to vehicle vibration and noise generated due to self-excited vibration. Is set to a value that does not feel The CVT clutch C2 corresponds to the clutch of the present invention.

  The shift control unit 102 ′ calculates the slip amount SLIP of the CVT travel clutch C2 as needed, and the CVT travel clutch C2 based on the deviation (SLIP * −SLIP) between the calculated slip amount SLIP and the target slip amount SLIP *. Execute feedback control. By executing the above control, slip occurs in the CVT travel clutch C2, and vibration transmitted to the drive wheels 14 is reduced. Further, the shift control unit 102 'fully engages the CVT clutch C2 when the slip speed ΔN reaches the target value ΔN *.

  FIG. 7 is a flowchart for explaining the control operation of the electronic control unit 80 'according to another embodiment of the present invention. When the flowchart of FIG. 7 is compared with the flowchart of FIG. 6 described above, only step S20 is added after step S9, and other controls are not changed. Hereinafter, step 20 will be mainly described.

  In FIG. 7, when S6 is negative, the target value ΔN * of the slipping speed ΔN is set in S9, and the belt clamping pressure (primary pressure Pin, secondary pressure is set so that the slipping speed ΔN follows the target value ΔN *. Feedback control of the pressure Pout) is executed. Next, in S20 corresponding to the function of the shift control unit 102 ', the self-excited vibration transmitted to the drive wheels 14 is reduced by sliding the CVT travel clutch C2. Therefore, vehicle vibration and noise generated during the feedback control of the belt clamping pressure are reduced.

  Also according to the present embodiment, the same effect as the above-described embodiment can be obtained. Further, when the slip speed ΔN is within a predetermined range, the slip speed ΔN is removed from the predetermined range, and the CVT travel clutch C2 is slid to cause self-excited vibration transmitted to the drive wheels 14 to be generated. The amount of transmission is reduced, and vehicle vibration and noise caused by self-excited vibration can be further reduced.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

  For example, in the above-described embodiment, the power transmission device 16 includes the continuously variable transmission 24 and the gear mechanism 28 in parallel, but the present invention is not necessarily limited thereto. For example, the gear mechanism 28 is not necessarily essential, and may be a conventional continuously variable transmission including the continuously variable transmission 24 between the engine 12 and the output shaft 30.

  In the above-described embodiment, whether or not the gear ratio γ of the continuously variable transmission 24 is the maximum gear ratio γmax is determined based on the primary pressure Pin and the secondary pressure Pout detected by the hydraulic pressure sensors 98 and 99. The gear ratio γ of the continuously variable transmission 24 may be determined based on the primary command pressure Pintgt of the primary pressure Pin and the secondary command pressure Pouttgt of the secondary pressure Pout. When the determination is made based on the command pressure in this way, the hydraulic pressure sensors 98 and 99 can be omitted.

  In the above-described embodiment, the learning control unit 110 decreases the predetermined value A, which is the lower limit value of the predetermined range of the sliding speed ΔN. However, the predetermined value A may be further increased. . For example, when the sliding speed ΔN is within a predetermined range, the rotational fluctuation ΔNout of the secondary pulley 62 is calculated, and when the calculated rotational fluctuation ΔNout is less than or equal to the predetermined value β, the predetermined value A is increased. It does not matter. Thus, the learning control unit 110 adjusts the predetermined value A to both the increase side and the decrease side.

  In the above-described embodiment, control for suppressing vehicle vibration and noise is executed based on the vehicle state determination unit 103 when the gear ratio γ, the input torque Tin, various rotational speeds, and the like are within a predetermined range. It was judged. However, it is not necessarily limited to these parameters. For example, if the vehicle is a 4WD vehicle, it may be a parameter related to self-excited vibration, such as being switched to 4WD traveling or if the torque ratio to the auxiliary drive wheel exceeds a predetermined value. It can be applied as appropriate. Further, the vehicle state determination unit 103 may be omitted, and control for suppressing vehicle vibration and noise may be executed at all times during CVT traveling.

  The above description is only an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

14: Drive wheel 24: Belt type continuously variable transmission 58: Primary pulley 62: Secondary pulley 64: Transmission belt 80, 80 ': Electronic control device (control device)
102, 102 ': Shift control unit (control unit)
104: Slip rate calculation unit 106: Slip speed calculation unit 110: Learning control unit A: Predetermined value (lower limit value)
B: Predetermined value (upper limit)
C2: CVT travel clutch (clutch)
η: slip rate ΔN: slip speed

Claims (7)

In a control device for a belt-type continuously variable transmission comprising a primary pulley, a secondary pulley, and a transmission belt wound around the primary pulley and the secondary pulley,
A slip speed calculating section for calculating a belt slip speed of the transmission belt;
A control unit that feedback-controls the belt clamping pressure of the transmission belt so as to deviate from the predetermined range when the slip speed is in the predetermined range ;
The predetermined range is a region between a preset lower limit value greater than zero and an upper limit value greater than the lower limit value,
When the slip speed is in the predetermined range, the control unit sets the slip speed to be equal to or higher than the upper limit value, or sets the slip speed to be equal to or lower than the lower limit value, depending on the traveling state of the vehicle. A control device for a belt-type continuously variable transmission. In the case where the sliding speed is within the predetermined range, and the difference between the sliding speed and the upper limit value is smaller than the difference between the sliding speed and the lower limit value, The control device for a belt-type continuously variable transmission according to claim 1 , wherein the slip speed is equal to or higher than the upper limit value. The control unit is a case where the slip speed is within the predetermined range, and an arrival time until the upper limit value is reached from the current slip speed until the lower limit value is reached from the current slip speed. reached when the short to be estimated than the time, the control apparatus for a belt-type continuously variable transmission according to claim 1, characterized in that the slip velocity than the upper limit value. A learning control unit configured to reduce the lower limit value of the predetermined range when the slippage speed is equal to or lower than the lower limit value of the predetermined range and the rotational fluctuation of the secondary pulley is larger than a predetermined value set in advance; The control device for a belt-type continuously variable transmission according to any one of claims 1 to 3 , further comprising: A clutch capable of changing the torque capacity is provided between the secondary pulley and the drive wheel,
The control device for a belt-type continuously variable transmission according to any one of claims 1 to 4 , wherein the controller slides the clutch when the slip speed is in the predetermined range. 2. The control device for a belt-type continuously variable transmission according to claim 1 , wherein the lower limit value is set to a value at which a rotation fluctuation of the secondary pulley is not more than a predetermined value set in advance. 2. The control device for a belt type continuously variable transmission according to claim 1 , wherein the upper limit value is set such that a frequency of vibration generated by belt slippage is out of a frequency range of vehicle vibration.

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