JP2869469B2 - Transmission control device for continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Industrial applications]

The present invention relates to a shift control device for a continuously variable transmission mounted on a vehicle having a traction control system (hereinafter, referred to as TCS) for controlling torque distribution between front and rear wheels according to a running state of the vehicle. The present invention relates to a shift control device for a continuously variable transmission that performs an accurate shift control corresponding to the above.

[Prior art]

A four-wheel drive vehicle with a traction control system (hereinafter referred to as TCS) that variably controls the torque distribution between the front and rear wheels in order to improve the straight running stability, acceleration, turning performance, steering stability, etc. according to the running condition of the vehicle Be prepared for
It has been proposed in recent years, and the present applicant has already made such a proposal (Japanese Patent Application Nos. 1-2222364 and 1-222366).
issue). The TCS is of an electronic and hydraulic control type including a TCS control unit that outputs a control signal to a hydraulic control system of a hydraulic clutch that performs torque transfer to front and rear wheels, and has an appropriate torque according to a traveling state of a vehicle. TCS to perform allocation control
Vehicle speed calculation means (pseudo vehicle speed calculation means) is provided in the control unit. Here, on a wet pavement or frozen road, the front wheel slips before the rear wheel, or if the front and rear wheels slip at the same time, it becomes impossible to steer, so it is necessary to always slip the rear wheel before the front wheel. is there. Therefore, in such a case, the torque distribution to the front wheels is increased within a range where a sufficient braking force can be secured by the torque control signal from the TCS control unit. On the other hand, as a continuously variable transmission mounted on a vehicle equipped with such a TCS, a belt-type continuously variable transmission that transmits power from a primary pulley on an input side to a secondary pulley on an output side via a drive belt is known. I have. As an example, a hydraulic control system that controls the belt wrap radius of the primary pulley and the secondary pulley is provided. There is known an apparatus in which a secondary pressure according to a transmission torque is applied to prevent a drive belt from slipping. Here, the control valve of the hydraulic control system for controlling the primary pressure and the secondary pressure tends to be electronically controlled by a control unit, and the control unit transmits a signal such as a vehicle speed (the rotational speed of a secondary pulley) and a throttle opening degree. The applicant of the present application has already proposed a method of inputting and determining an appropriate target gear ratio according to the traveling conditions of the vehicle, and outputting a gear shift control signal so that the gear ratio of the continuously variable transmission follows the target gear ratio. JP-A-64-52535). In addition, as an example of electronically controlling the shift control of the continuously variable transmission, there is another prior art described in JP-A-63-303258, and the electronic control is performed in response to wheel slip. As for what to do, JP-B-53-24687, JP-B-57
There is a prior art described in JP-A-2949.

[Problems to be solved by the invention]

By the way, in a vehicle in which the torque distribution to the front wheels is controlled by the TCS control unit to increase with the braking operation, the rear wheels slip before the front wheels, and at that time, the rotation speed of the rear wheels does not correspond to the vehicle speed . Also, when a large amount of torque is distributed to the rear wheel side during rapid acceleration, the rear wheel slips, and the rotation speed of the rear wheel similarly does not correspond to the vehicle speed. For this reason, the vehicle speed signal (the rotational speed signal of the secondary pulley), which is the speed change condition of the continuously variable transmission, does not correspond to the actual vehicle speed, and the continuously variable transmission rapidly becomes unstable. If such a state is left unchecked, the durability of the continuously variable transmission decreases, for example, vibration occurs in the continuously variable transmission, and a slip occurs in the drive belt due to a decrease in the secondary pressure. Therefore, the present invention prevents a meaningless change in gear ratio by switching from normal gear shift control to gear shift control corresponding to TCS operation when TCS control according to the running state of the vehicle is performed, thereby preventing stepless change in gear ratio. It is intended to reduce vibration and improve durability of the transmission.

[Means for Solving the Problems]

For this purpose, the present invention is mounted on a vehicle equipped with a traction control system that controls the torque distribution of the front and rear wheels according to the running state of the vehicle, and is based on a primary pulley speed signal and a secondary pulley speed signal. In a transmission control device for a continuously variable transmission having a speed ratio calculating means for calculating a speed ratio, a drive signal for driving a traction control system is output based on a rotation speed of a front wheel and a rotation speed of a rear wheel of a vehicle. A traction control system drive signal output unit, a simulated vehicle speed calculation unit that calculates a simulated vehicle speed based on the rotation speeds of the front wheels and the rear wheels of the vehicle and outputs a simulated vehicle speed signal, and the traction control system. Traction control from the system drive signal output means and the pseudo vehicle speed calculation means, respectively. A secondary pulley pseudo-rotation speed calculating means that receives a system drive signal and a pseudo vehicle speed signal to calculate a pseudo rotation speed of a secondary pulley and outputs a secondary pulley pseudo rotation speed signal; and a secondary pulley for calculating the speed ratio. When a rotation speed signal is input and the secondary pulley rotation speed signal is output from the secondary pulley pseudo rotation speed calculation unit to the secondary pulley pseudo rotation speed signal, the secondary pulley pseudo rotation speed signal is input to the secondary pulley pseudo rotation speed signal. Output switching means for outputting the number signal to the speed ratio calculating means in place of the secondary pulley rotation speed signal.

[Action]

With such means, during normal running of the vehicle, the continuously variable transmission is controlled to the optimal speed ratio in accordance with the speed change control signal output from the control unit. Here, when a brake operation is performed or a slip occurs on a wheel, a TCS drive signal is output in accordance with the TCS control. Therefore, in the control unit, the secondary pulley pseudo-rotational speed calculation unit that receives the TCS drive signal and the pseudo vehicle speed signal outputs a secondary pulley pseudo-rotational speed signal in accordance with the pseudo vehicle speed signal. Then, this pseudo rotation speed signal is output from the output switching unit in preference to the rotation speed signal of the secondary pulley, so that the normal shift control is temporarily suspended, and the control unit performs the shift control according to the pseudo vehicle speed. Become. For this reason, meaningless fluctuations in the speed ratio are eliminated, and the continuously variable transmission has reduced vibration and improved durability.

【Example】

Hereinafter, an embodiment of the present invention will be specifically described with reference to the accompanying drawings. First, a schematic configuration of a drive system of a vehicle equipped with a continuously variable transmission will be described with reference to FIG. This vehicle is a four-wheel drive vehicle with a center differential configured to be capable of unequal torque distribution to front and rear wheels by a traction control system, and is configured to transmit power from an engine 1 to a continuously variable transmission 3 via a clutch 2. The transmission output shaft 4 is a center differential device 5
Through the front drive shaft 6 and the rear drive shaft 7. And front drive shaft 6
Is connected to left and right front wheels 10 via a front differential device 8 and an axle 9, and the rear drive shaft 7 is connected to left and right rear wheels 14 via a propeller shaft 11, a rear differential device 12 and an axle 13. The center differential device 5 is of a compound planetary gear type and has a first sun gear 15 connected to the transmission output shaft 4 and a second sun gear 16 connected to the rear drive shaft 7. The first sun gear 15 has
First pinion gear 17 of pinion group 17 coaxially connected
a and the second sun gear 16 has a second pinion gear 17b
Are engaged. A carrier 18 that supports the pinion group 17 is connected to a reduction drive gear 19 rotatably supported on the transmission output shaft 4, and the reduction drive gear 19 meshes with a reduction driven gear 20 of the front drive shaft 6. ing. And such a center differential device 5
Inputs the power from the transmission output shaft 4 from the second sun gear 15 to the first pinion gear 17a.
Distributed to the front drive shaft 6 via the reduction drive gear 19 and the reduction driven gear 20, and to the rear drive shaft 7 via the second pinion gear 17b and the second sun gear 16 in the local area, respectively. The distribution is made. The rotation of the pinion group 17 in a planetary manner absorbs the difference in rotation speed between the front and rear wheels 10 and 14 when the vehicle turns. Here, the center differential device 5 is provided with a hydraulic clutch 21 for limiting the differential. The hydraulic clutch 21 includes, for example, a drum 21a on the carrier 18 and a hub 21b.
Is coupled to the rear drive shaft 7, and performs torque movement by bypassing from the rear wheel 14 to the front wheel 10 in accordance with the differential limiting torque Tc by hydraulic control, thereby distributing the torque distribution of the front and rear wheels to the rear wheel biasing. To a differential lock state which is directly connected. The hydraulic control system of the hydraulic clutch 21 includes an oil pump 30 driven by the engine 1, a regulator valve 31, a clutch control valve 32, a pilot valve 33, a duty solenoid valve 34, and the like. A pressure oil passage 35 communicates with the hydraulic clutch 21 from the clutch control valve 32 via an oil passage 36. The line pressure oil passage 35 communicates with a duty solenoid valve 34 through an oil passage 38 having a pilot valve 33 and an orifice 37, and the duty pressure of the duty solenoid valve 34 is applied to the control side of the clutch control valve 32 via oil 39. To work. Then, the duty solenoid valve 34 is operated by a control signal from a TCS control unit 70 described later, and the clutch control valve 32 is operated according to the duty pressure, so that the differential limiting torque Tc is varied together with the clutch pressure of the hydraulic clutch 21. Traction control system (TCS). Next, the configuration of the continuously variable transmission 3 and its hydraulic control system will be described with reference to FIG. The continuously variable transmission 3 is a belt-type continuously variable transmission whose pulley ratio is variably controlled. A transmission input shaft 40 connected to the clutch 2 is connected to a primary shaft 42 via a forward / reverse switching device 41. A primary pulley 43 provided on the primary shaft 42 and a secondary pulley provided on the secondary shaft 44
A drive belt 46 is wound between the drive belt 45 and the drive belt 45. A primary hydraulic cylinder 47 is provided on the movable side of the primary pulley 43, and a secondary hydraulic cylinder 48 is provided on the movable side of the secondary pulley 45. Here, the pressure receiving area of the primary hydraulic cylinder 47 is set to be larger than that of the secondary hydraulic cylinder 48, and the winding radius of the drive belt 46 is changed by the primary pressure Pp to change the pulley ratio steplessly. The secondary shaft 44 is connected to the transmission output shaft 4 via a set of reduction gears 49. The hydraulic control system of the continuously variable transmission 3 shares the oil pump 30, and the line pressure oil passage 50 on the discharge side of the oil pump 30 includes a secondary hydraulic cylinder 48 and a line pressure control valve 51.
And directly through the line pressure control valve 51 to the speed change control valve 52. The shift speed control valve 52 is a two-position switching valve for switching between oil supply and oil discharge, and is provided with a line pressure oil passage.
It communicates with the primary hydraulic cylinder 47 via 53. The line pressure oil passage 50 communicates with a regulator valve 55 through an orifice 54. An oil passage 56 of the regulator pressure PR regulated by the regulator valve 55 is connected to a line pressure control solenoid valve through an orifice 57. A solenoid valve for shifting speed control which communicates with 58 and through an orifice 59
Communicate with 60. Further, the regulator pressure PR of the oil passage 58 acts on the shift speed control valve 52 via the orifice 61, and switches the shift speed control valve 52 to the oil discharge side. The line pressure control solenoid valve 58 and the shift speed control solenoid valve 60 are turned on and exhausted by a duty signal from the control unit 90, turned off to output the regulator pressure PR, and correspond to the duty signal. A pulse-like control pressure is generated. The pulse control pressure from the line pressure control solenoid valve 58 is averaged by the accumulator 62 and acts on the line pressure control valve 51. On the other hand, the pulse-like control pressure from the shift speed control solenoid valve 60 acts on the shift speed control valve 52 as it is, and switches it to the refueling side. The line pressure control valve 51 controls the line pressure PL based on the speed ratio i of the continuously variable transmission 3 and the engine torque T by the averaged control pressure from the solenoid valve 58 for line pressure control. The shift speed control valve 52 is connected to the line pressure oil passages 50 and 53 by the relationship between the regulator pressure PR and the pulse control pressure from the shift speed control solenoid valve 60, and the line pressure oil passage 53 The operation is switched to two positions, i.e., a drain position and a drain position. By switching between the two positions in accordance with the duty ratio, the flow rate Q of oil supply or drainage to the primary hydraulic cylinder 47 is controlled. As a result, the speed ratio i of the continuously variable transmission 3 is changed, and the speed ratio change speed di is changed. / dt is also changed. Here, a flow rate sensor 65 is provided in the line pressure oil passage 53 so as to monitor the flow rate Q of supply / discharge oil to / from the primary hydraulic cylinder 47 and feed it back to the control unit 90. In FIG. 2, reference numeral 63 denotes a drain oil passage, and 64 denotes an oil pan. FIG. 3 shows the configuration of the TCS control unit 70. This T
The CS control unit 70 basically performs feedback control of torque distribution based on the slip ratio of a rear wheel that always slips first due to rear wheel bias. Therefore, first, the basic control will be described.
The relationship between the lateral force F and the lateral force F is as shown in FIG. That is, the lateral force F is maximum in the non-slip state (S = O), and gradually decreases as the slip ratio S increases. In addition, the driving force Ts increases from the non-slip state (S = O) to the slip rate Sa (10 to 20%) as the slip rate S increases, and thereafter decreases.
Therefore, if the slip ratio S is controlled in the range of S ≦ Sa, the lateral force F can be kept high and the stability of the rear wheel 14 can be secured. The slip ratio S is expressed as follows using the ground vehicle speed V, the tire radius r, and the rear wheel angular speed ωR. S = (r · ωR−V) / r · ωR Here, the rear wheel slip ratio S with unequal torque distribution of about 3: 7
Is controlled within a substantially linear region where S <Sa, the slip ratio S of the front wheels 10 is always small and can be made approximately equal to the vehicle speed. That is, front wheel angular velocity ωF, tire radius r
Then, V = r · ωF. Therefore, the above-mentioned slip ratio S can be expressed as follows. S = (r · ωR−r · ωF) / r · ωR = (ωR−ωF) / ωR Furthermore, since the center differential function at the time of turning is not impaired, an apparent slip caused by the difference between the front and rear wheel rotational speeds of full steering. The predetermined slip ratio Sb including the ratio (for example, 3
%) Is set as a dead zone.
Becomes Sb <S <Sa. Therefore, if the slip ratio S is calculated in the control range D and the differential limiting torque Tc is controlled in an increasing function with respect to the slip ratio S, the torque moves from the rear wheel bias to the front wheel 10 side, and the rear wheel 14 Can always be kept high. Therefore, the TCS control unit 70 includes the front wheel speed sensor 71
From the front wheel angular velocity signal ωF and the rear wheel angular velocity signal ωR from the rear wheel rotational speed sensor 72 are input to the rear wheel slip rate calculating means 73, and the slip rate S is calculated by the above-described equation S = (ωR−ωF) / ωR. I do. The signal of the slip ratio S is supplied to the differential limiting torque setting means 74.
And the differential limiting torque Tc is determined. Here, the differential limiting torque Tc is set by an increasing function in the control range of Sb <S <Sa over the slip ratio S as shown in FIG. 4 (b). The dynamic limiting torque setting means 74 sets the differential limiting torque Tc. The differential limiting torque Tc is basically input to the control amount setting means 75, where it is converted into a duty ratio D according to the differential limiting torque Tc. Then, the duty ratio signal D is output to the duty solenoid valve 34 as a TCS drive signal T via the drive means 78. Further, the TCS control unit 70 controls the front wheel angular velocity signal ω
F and a rear wheel angular velocity signal ωR from the rear wheel speed sensor 72
And a throttle opening sensor 78, a steering angle sensor 79, a brake switch 8
0, signal input from idle switch 81. The pseudo vehicle speed calculating means 77 calculates the pseudo vehicle speed Vs by averaging the front wheel angular speed signal ωF and the rear wheel angular speed signal ωR, and the pseudo vehicle speed signal Vs and the detection signals from the sensors and switches 78 to 81 are: It is input to the fixed condition determining means 82. This fixed condition determining means 82 is
a, steady high-speed running determining means 82b, low-speed large turning determining means 82
c, has a brake operation determining means 82d and a deceleration determining means 82e, and according to the input throttle opening signal θ, steering angle signal ψ, brake signal, idle signal, vehicle speed signal V, etc., Determine if there is. The determination signal from the fixed condition determining means 82 is input to the correcting means 83 provided on the output side of the differential limiting torque setting means 74, and corrected and held to an optimal torque distribution for each traveling condition. It is supposed to. Here, the TCS control unit 70 receives the TCS drive signal T from the drive means 76 and the pseudo vehicle speed signal Vs from the pseudo vehicle speed calculation means 77.
Are output to the control unit 90 of the continuously variable transmission 3. FIG. 5 shows the configuration of the control unit 90 of the continuously variable transmission 3. The flow rate sensor 65, the primary pulley rotation speed sensor 91 for detecting the rotation speed of the primary pulley 43, the secondary pulley rotation speed sensor 92 for detecting the rotation speed of the secondary pulley 45, the throttle opening sensor 78, the rotation of the engine 1 Each detection signal from the engine speed sensor 94 for detecting the number is input, and the speed change control and the line pressure control of the continuously variable transmission 3 are performed. First, the shift speed control system will be described. A primary pulley rotation speed sensor 91 and a secondary pulley rotation speed sensor are described.
An actual speed ratio calculating section 95 is provided which receives the primary pulley speed signal Np and the secondary pulley speed signal Ns from 92 and calculates the actual speed ratio i. Then, the actual speed ratio signal i and the throttle opening signal θ from the throttle opening sensor 78 are input to the target primary pulley rotation speed search unit 96,
Therefore, the target primary pulley rotation speed Npd corresponding to the accelerator depression amount is retrieved from a predetermined shift pattern prepared in advance. The target primary pulley rotation speed signal Npd and the secondary pulley rotation speed signal Ns are input to a target gear ratio calculator 97, where a target gear ratio is is calculated. Also provided is a target speed ratio change speed calculating unit 100 that inputs the target speed ratio signal is and a signal from a coefficient setting unit 99 for setting the coefficients of k1 and k2 to calculate a target speed ratio change speed dis / dt. . The output signal dis / dt, the target gear ratio signal is, and the actual gear ratio signal i from the target gear ratio change speed calculator 100 are input to the gear speed calculator 98, respectively. This shift speed calculator
In step 98, the speed ratio change speed di / dt is obtained by the following equation in order to bring the actual speed ratio i closer to the target speed ratio is. di / dt = k1 (is−i) + k2 · dis / dt The obtained signal of di / dt and the actual speed ratio signal i are input to the target flow rate calculating means 101, where the primary hydraulic cylinder 47 of the primary pulley 43 is provided. Required flow rate Qs corresponding to the gear ratio change speed di / dt
Is calculated. On the other hand, a flow deviation calculating means 102 for inputting the target flow signal Qs and a signal of the actual flow Q to the primary hydraulic cylinder 47 detected by the flow sensor 65 is provided, and a deviation ΔQ between the target flow Qs and the actual flow Q is provided. Is calculated. Then, the duty ratio determining unit 103 receiving the deviation signal ΔQ outputs the actual flow rate Q
Is determined so as to approach the target flow rate Qs. The duty ratio signal D determined by the duty ratio determination unit 103 is supplied to the speed ratio control solenoid valve 60 via a driving unit 104, and the opening of the speed change speed control valve 52 is controlled by a hydraulic pressure corresponding to the duty ratio D. The area Si is changed, and the required flow rate Qi corresponding to the speed ratio change speed di / dt is supplied to the primary hydraulic cylinder 47. Next, the line pressure control system includes an engine torque search unit 105 that receives the throttle opening signal θ and the engine speed signal Ne from the engine speed sensor 94 and obtains the engine torque T by searching a map or the like. Then, the target line pressure setting unit 106, which inputs the engine torque signal T and the actual speed ratio signal i, sets a target line pressure PLd of the line pressure oil passage 50, that is, to the secondary hydraulic cylinder 48. On the other hand, a maximum line pressure PLmax, that is, a maximum line pressure inspection unit 107 which receives the engine speed signal Ne and the actual speed ratio signal i and predicts the maximum line pressure PLmax, that is, the original pressure, is provided. Based on PLd, the reduced pressure value calculation unit 108 calculates the reduced pressure value PLR by the following equation. PLR = PLmax−PLd Then, the duty ratio search unit 109 obtains a duty ratio with respect to the calculated reduced pressure value PLR by searching, and the driving unit 110
, And the line pressure control solenoid valve 58 is duty-driven. In this way, the line pressure PL of the line pressure oil passage 50, that is, the secondary pressure Ps is controlled so as to become the target line pressure PLd corresponding to the engine torque T and the actual speed ratio i. Here, the control unit 90 is provided with a secondary pulley pseudo rotation speed calculation unit 111 and an output switching unit 112 in order to perform appropriate shift control corresponding to the TCS operation depending on the running state. The secondary pulley pseudo rotation speed calculation unit 111 receives the pseudo vehicle speed signal Vs and the TCS drive signal T from the TCS control unit 70, and calculates the pseudo rotation speed Nss of the secondary pulley 45. Here, assuming that the gear ratio from the secondary pulley 45 to, for example, the rear wheel 14 is G, there is a relationship of Vs = f (Nss · G), and the relationship of Nss = f (Vs / G) holds from this. Therefore, the secondary pulley pseudo rotation speed calculation unit 111 calculates the pseudo rotation speed Nss as a function of the pseudo vehicle speed Vs and the gear ratio G. The output switching unit 112 receives the pseudo rotation speed signal Nss from the secondary pulley pseudo rotation speed calculation unit 111 and the actual secondary pulley rotation speed signal Ns, and gives priority to the pseudo rotation speed signal Nss over the secondary pulley rotation speed signal Ns. It is provided in the middle of a signal path from the secondary pulley rotation speed sensor 92 to the actual speed ratio calculating section 95 and the target speed ratio calculating section 97. Next, the operation of the shift control device for a continuously variable transmission having the above configuration will be described. First, a description will be given of a normal running state of a vehicle in which TCS control is not performed due to a change in a running state.
In the control unit 90, the target speed ratio is and the actual speed ratio i are set to values larger than, for example, 2.5 as the maximum speed ratio on the mechanism of the continuously variable transmission 3. Therefore, the duty ratio determination unit 103 determines a predetermined duty ratio D based on the setting conditions,
The signal is supplied to the gear ratio control solenoid valve 60 via the drive unit 104. Therefore, the opening area Si of the transmission speed control valve 52 changes according to the hydraulic pressure according to the duty ratio D, and the minimum required flow rate Qi corresponding to the transmission ratio change speed di / dt is supplied to the primary hydraulic cylinder 47. Thus, the primary pressure Pp becomes the lowest level, and the continuously variable transmission 3 drives the drive belt 46.
Is the lowest speed stage having the maximum gear ratio that has shifted to the secondary pulley 45 most. On the other hand, in the line pressure control system, the engine torque T is estimated based on the throttle opening signal θ and the engine speed signal Ne. In order to control the target line pressure PLd in accordance with the engine torque T and the actual gear ratio i. The predetermined duty ratio is supplied to the line pressure control solenoid valve 58 via the drive unit 110. Therefore, the secondary pressure of the secondary pulley 45
Ps becomes the target line pressure PLd corresponding to the engine torque T and the actual gear ratio i, and the continuously variable transmission 3 is in a state where power can be transmitted. Therefore, when the vehicle starts, the power of the engine 1 is input to the primary shaft 42 of the continuously variable transmission 3 via the clutch 2, the transmission input shaft 40, and the forward / reverse switching device 41, and from the primary pulley 43 to the drive belt 46, Power having the maximum speed ratio is taken out to the secondary shaft 44 via the secondary pulley 45. When this power is input from the transmission output shaft 4 to the center differential device 5 via the reduction gear 49, the vehicle starts with a predetermined reference torque distribution of rear wheel bias. Thereafter, the control unit 90 performs the speed change control based on the target speed ratio is and the engine torque T from low speed to high speed according to the driving conditions of the vehicle, and the vehicle runs with sufficient engine performance. Next, shift control in the case where TCS control is performed based on a change in the running state of the vehicle will be described. When the brake operation is performed, in the TCS control unit 70, the brake operation determination means 82d of the fixed condition determination means 82 outputs the determination signal based on the brake signal detected by the brake switch 80. Then, the correcting means 83 corrects the differential limiting torque Tc to a predetermined value, and the corrected differential limiting torque Tc
Is output to the duty solenoid valve 34 as a TCS drive signal T via the drive means 76, so that the brake is effective and the skid is unlikely to occur. Is done. At this time, the pseudo vehicle speed signal Vs from the pseudo vehicle speed calculating means 77 is output to the control unit 90. Therefore, on the control unit 90 side, the pseudo vehicle speed signal Vs and TC
The secondary pulley pseudo rotation speed calculation unit 111 that has received the S drive signal T and outputs the pseudo rotation speed signal Nss of the secondary pulley 45.
Is output to the output switching unit 112.
The pseudo speed signal Nss is given priority over the secondary pulley speed signal Ns, and the actual speed ratio calculation unit 95 and the target speed ratio calculation unit 97
Output to For this reason, when the TCS control according to the brake operation and the wheel slip is performed, the above-described shift control of the normal continuously variable transmission 3 is temporarily suspended, and the actual speed ratio i and the target speed ratio is set to the pseudo rotational speed. The control is performed based on the signal Nss, and the shift control of the control unit 90 is in accordance with the pseudo vehicle speed Vs. Therefore, there is no meaningless change in the speed ratio caused by the fact that the rotation speed Ns of the secondary pulley 45 greatly changes with the operation of the TCS, and a speed ratio corresponding to the vehicle speed is obtained. And the vibration of the continuously variable transmission 3 is reduced, and the durability is improved. When the output of the pseudo vehicle speed signal Vs and the output of the TCS drive signal T from the TCS control unit 70 is stopped, the secondary pulley pseudo rotation speed calculation unit 111 stops outputting the pseudo rotation speed signal Nss. The rotation number signal Ns is output, and thus the control unit 90 returns to the normal shift control. Therefore, even at the time of releasing the brake operation, it is possible to quickly control the return from the speed ratio corresponding to the vehicle speed to the normal speed ratio. In the above-described embodiment, the pseudo vehicle speed calculating means 77 for inputting signals from the front wheel speed sensor 71 and the rear wheel speed sensor 72 to calculate the pseudo vehicle speed Vs is provided in the TCS control unit 70. The pseudo vehicle speed calculating means may be provided in the control unit 90 of the continuously variable transmission. The pseudo vehicle speed calculating means may calculate a pseudo vehicle speed by inputting a signal from an acceleration sensor of the vehicle or the like.

【The invention's effect】

As described above, according to the present invention, during normal running of the vehicle, the continuously variable transmission is controlled to the optimal speed ratio in accordance with the speed change control signal output from the control unit. Here, when a brake operation is performed or a slip occurs on a wheel, a TCS control signal is output in conjunction with the TCS control. Therefore, in the control unit, the secondary pulley pseudo-rotational speed calculation unit that receives the TCS drive signal and the pseudo vehicle speed signal outputs a secondary pulley pseudo-rotational speed signal in accordance with the pseudo vehicle speed signal. Then, this pseudo rotation speed signal is output from the output switching unit in preference to the rotation speed signal of the secondary pulley, so that the normal shift control is temporarily suspended, and the control unit performs the shift control according to the pseudo vehicle speed. Become. For this reason, there is no meaningless change in the speed ratio, and the vibration of the continuously variable transmission can be reduced and the durability can be improved. Then, since the pseudo vehicle speed at the time of traction control is calculated based on the rotation speeds of the front wheels and the rear wheels of the vehicle, the shift control at the time of traction control can be appropriately performed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a drive system of a vehicle on which a continuously variable transmission according to an embodiment of the present invention is mounted, together with a hydraulic control system of a hydraulic clutch. FIG. FIG. 3 is a block diagram around the TCS control unit, FIG. 4 (a) is a characteristic diagram of driving force and lateral force with respect to a slip ratio, and FIG. 4 (b) is a schematic diagram of a hydraulic control system of the shift control device. FIG. 5 is a block diagram around a control unit of the transmission control device. 1 ... engine, 2 ... clutch, 3 ... continuously variable transmission, 5 ... center differential device, 6 ... front drive shaft, 7 ... rear drive shaft, 10 ... front wheel, 14 ... rear wheel, 21… Hydraulic clutch, 32… Clutch control valve, 34… Dute solenoid valve, 41… Forward / reverse switching device, 42 …… Primary shaft, 43 …… Primary pulley, 44 …… Secondary shaft, 45 …… Secondary pulley, 46… Drive belt, 47… Primary hydraulic cylinder, 48… Secondary hydraulic cylinder, 51… Line pressure control valve, 52… Shift speed control valve, 55… Regulator valve, 58… Line pressure Solenoid valve for control, 60: Solenoid valve for speed change control, 65: Flow rate sensor, 70: TCS control unit, 71: Front wheel speed sensor, 72: Rear wheel speed sensor, 73: Rear wheel Slip rate Output means 74 differential limiting torque setting means 77 pseudo vehicle speed calculating means 90 control unit 95 actual gear ratio calculating section 97 target gear ratio calculating section 103 duty ratio Determining unit 104 driving unit 109 duty ratio searching unit 110 driving unit 111 secondary pulley pseudo rotation speed calculating unit 112 output switching unit

Continued on the front page (51) Int.Cl. ⁶ Identification code FI F16H 59:50

Claims (1)

(57) [Claims] 1. A vehicle equipped with a traction control system for controlling a torque distribution between front and rear wheels according to a running state of a vehicle, wherein a gear ratio is determined based on a primary pulley speed signal and a secondary pulley speed signal. A transmission control device for a continuously variable transmission having a transmission ratio calculating means for calculating a traction control system for outputting a drive signal for driving a traction control system based on a rotation speed of a front wheel and a rotation speed of a rear wheel of the vehicle. Control system drive signal output means, pseudo vehicle speed calculation means for calculating a pseudo vehicle speed based on the rotational speeds of the front wheels and the rear wheels of the vehicle and outputting a pseudo vehicle speed signal, and the traction control system drive signal A traction control system from the output means and the pseudo vehicle speed calculating means. A secondary pulley pseudo-rotation speed calculating means that receives the drive signal and the pseudo vehicle speed signal to calculate a pseudo rotation speed of the secondary pulley and outputs a secondary pulley pseudo rotation speed signal, and a secondary pulley rotation speed for calculating the speed change ratio. A signal is input to output the secondary pulley rotation speed signal to the speed ratio calculating means, and when the secondary pulley pseudo rotation speed signal is input from the secondary pulley pseudo rotation speed calculation means, the secondary pulley pseudo rotation speed signal is output. And an output switching means for outputting to the gear ratio calculating means in place of the secondary pulley rotation speed signal.