JP3006840B2 - Transmission control device for continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention provides an anti-lock brake system (hereinafter
More specifically, the present invention relates to a shift control device for a continuously variable transmission that performs a shift control corresponding to an ABS operation.

[Prior art]

In general, when a vehicle is suddenly braked while traveling on a wet pavement or a frozen road, wheels may be locked, and braking and steering cannot be performed. Further, even when the wheels are not locked, if the slip ratio of the wheels increases, sufficient braking force or steering performance cannot be obtained. Therefore, in recent years, there has been a tendency to equip vehicles with an ABS that ensures a sufficient braking force and steering performance by controlling a slip ratio of a wheel during a brake operation within an appropriate region. On the other hand, as such a continuously variable transmission mounted on a vehicle, 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. As an example, a hydraulic control system that controls a belt winding radius of a primary pulley and a secondary pulley is provided, and a primary pressure according to a speed ratio is applied to the primary pulley to change a winding radius of a drive belt, and a secondary pulley is 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 that controls the primary pressure and the secondary pressure tends to be electronically controlled by a control unit. For this control unit, a vehicle speed, a throttle opening, and the like are input to adjust the traveling conditions of the vehicle. It has been considered that an appropriate target gear ratio is determined in accordance therewith, and a gear ratio control signal is output so that the gear ratio of the continuously variable transmission follows the target gear ratio. An electronic control of the shift control of the continuously variable transmission is disclosed in, for example, Japanese Patent Application Laid-Open No. Sho 63-303258. The electronic control is performed in response to wheel slip. There are prior arts described in JP-B-53-24687 and JP-B-57-2949.

[Problems to be solved by the invention]

By the way, in a vehicle that is subjected to ABS control at the time of a brake operation, the brake pressure is repeatedly increased and decreased to prevent wheel lock, so that the wheel rotation speed increases and decreases in a short cycle. This means that the vehicle speed signal, which is the shift condition of the continuously variable transmission, increases and decreases in a short cycle, and the continuously variable transmission unnecessarily repeats the downshift and the upshift, and becomes an unstable state. If such a state is left, not only is the delay in performing the return control to the normal speed ratio when the brake is released, but also the line pressure of the hydraulic control system is reduced and the secondary pressure is reduced, and the drive belt slips. The inconvenience of wear is expected. Therefore, the present invention prevents slippage of the drive belt beforehand by switching from normal speed ratio control to speed change control corresponding to the time of ABS operation when ABS control is performed by the brake operation of the vehicle, and when the brake is released. It is an object of the present invention to enable quick return control to a normal speed ratio.

[Means for Solving the Problems]

For this purpose, the invention provides an anti-lock brake
A transmission control device for a continuously variable transmission that continuously controls a speed ratio of a continuously variable transmission mounted on a vehicle equipped with a system according to a speed ratio control signal output from a control unit. The control unit has an anti-lock brake system operation detection unit that detects when the anti-lock brake system is operating, and receives an operation signal from the anti-lock brake system operation detection unit to input an anti-lock brake system operation signal. A control signal holding unit for holding the speed ratio control signal immediately before the operation of the brake system, and an output switching unit for receiving the speed ratio control signal and a hold signal from the control signal holding unit; The part is the above anti-lock brake
While the system is operating, it is characterized in that the gear ratio control signal held by the control signal holding unit is continuously output with priority.

[Action]

With such a means, the continuously variable transmission is steplessly controlled to the optimal speed ratio in accordance with the speed ratio control signal output from the control unit during normal running of the vehicle in which the ABS control is not performed. Here, when the ABS control is performed by the brake operation of the vehicle, the ABS operation detecting unit outputs a detection signal, and the control signal holding unit holds the speed ratio control signal immediately before the ABS operation. The hold signal is output by the output switching section prior to the gear ratio control signal, so that the normal gear ratio control is temporarily suspended, and the gear ratio is held at the gear ratio immediately before the ABS operation. For this reason, unnecessary shift operations are eliminated, and the line pressure and the secondary pressure of the hydraulic control system are maintained at predetermined values, thereby preventing the drive belt from slipping. When the brake operation is released, the gear ratio is immediately returned to the normal gear ratio from the gear ratio immediately before the ABS operation.

【Example】

Hereinafter, an embodiment of the present invention will be specifically described with reference to the accompanying drawings. First, the outline of the drive system of a continuously variable transmission with a lock-up torque converter will be described with reference to FIG. 1. In the figure, reference numeral 1 denotes an engine, and a crankshaft 2 includes a torque converter device 3;
The transmission is sequentially transmitted to the forward / reverse switching device 4, the continuously variable transmission 5, and the differential device 6. In the torque converter device 3, a drive plate 10 connected to the crankshaft 2 is connected to a pump impeller 12 a of a torque converter 12 via a converter cover 11. The turbine runner 12b of the torque converter 12 is connected to the turbine shaft 13, and the stator 12c is guided by a one-way clutch 14. A lock-up clutch 15 integrated with the turbine runner 12b is installed so as to be able to engage or disengage with the drive plate 10, and engine power is transmitted via the torque converter 12 or the lock-up clutch 15. The forward / reverse switching device 4 has a double pinion type planetary gear 16, the sun gear 16 a of which is input from the turbine shaft 13 and output from the carrier 16 b to the primary shaft 20. A forward clutch 17 is provided between the sun gear 16a and the carrier 16b, and the planetary gear 16 is integrated by the engagement thereof to directly connect the turbine shaft 13 and the primary shaft 20. Further, a reverse brake 18 is provided between the ring gear 16c and the case, and outputs reverse power to the primary shaft 20 by the engagement. And forward clutch 17 and reverse brake 18
Release the planetary gear 16. The continuously variable transmission 5 includes a primary pulley 22 of a variable pulley distance having a primary cylinder 21 on a primary shaft 20 serving as an input shaft, and a similar secondary pulley 25 having a secondary cylinder 24 on a secondary shaft 23 serving as an output shaft. The drive belt 26 is provided between the primary pulley 22 and the secondary pulley 25. Here, the primary cylinder 21 is the secondary cylinder
The pressure receiving area is set to be larger than 24, and the ratio of the winding radius of the drive belt 26 to the primary pulley 22 and the secondary pulley 25 is changed by the primary pressure to perform stepless transmission. In the differential device 6, an output shaft 28 is connected to the secondary shaft 23 via a pair of reduction gears 27,
The drive gear 29 of the output shaft 28 meshes with the final gear 30. A differential gear 31 connected to the final gear 30 is connected to left and right wheels 33 via an axle 32. On the other hand, an oil pump 34 is provided adjacent to the torque converter 12 in order to obtain a hydraulic pressure source for controlling the continuously variable transmission 5. The oil pump 34 is connected to the converter cover 11 by a pump drive shaft 35, and is constantly driven by engine power to generate hydraulic pressure. Here, since the control oil pressure of the continuously variable transmission 5 has a wide range of height, the oil pump 34 is, for example, of a roller vane type and of a variable displacement type having a plurality of sets of suction and discharge ports. Next, the hydraulic control system of the continuously variable transmission 5 will be described. An oil passage 41 from the oil pump 34 communicating with the oil pan 40 communicates with a secondary control valve 50 to generate a predetermined secondary pressure Ps. The pressure Ps is always supplied to the secondary cylinder 24 through the oil passage 42. The secondary pressure Ps is guided to the primary control valve 55 via the oil passage 43, where a predetermined primary pressure Pp is generated to supply and discharge oil to and from the primary cylinder 21 via the oil passage 44. The secondary control valve 50 is of a proportional solenoid relief valve type, and a proportional solenoid 51 is supplied with a solenoid current Is from a control unit 70. Then, the electromagnetic force generated by the solenoid current Is is applied to the spool against the hydraulic reaction force and the spring force of the secondary pressure Ps, and the pressure is adjusted in a balanced manner. That is, the set pressure is made variable by the solenoid current Is, and the secondary pressure Ps is controlled in a one-to-one proportional relationship with the solenoid current Is. The primary control valve 55 is of a proportional electromagnetic relief valve type, and a solenoid current Ip is supplied from the control unit 70 to the proportional solenoid 56, similarly to the secondary control valve 50. The electromagnetic force generated by the solenoid current Ip is applied to the spool against the hydraulic reaction force and the spring force of the primary pressure Pp, and the set pressure is made variable by the solenoid current Ip. With primary pressure
Pp is controlled. The oil pump 34 is of a variable displacement type as described above, and a relatively high lubricating pressure is always generated in the oil passage 45 on the drain side of the secondary control valve 50. Therefore, the circuit is configured such that the lubricating pressure is supplied to the torque converter 12, the forward / reverse switching device 4, the lubricating portion of the drive belt 26 and the like. FIG. 2 shows a schematic configuration of the ABS. This is a type in which the brake pressure of the four front and rear wheels is electronically controlled by a microcomputer 60. In the middle of the brake hydraulic system from the master cylinder 61 to the wheel cylinder of each wheel 33, a hydraulic unit 63 and a proportioning valve are provided.
A wheel speed sensor 65 for detecting the number of rotations of each wheel 33 is provided on each wheel 33. The microcomputer 60 calculates the speed, acceleration / deceleration, estimated vehicle speed, and the like of each wheel 33 based on the detection signal of each wheel speed sensor 65. Then, comparing the estimated vehicle speed with the wheel speed, judging from the magnitude of acceleration and deceleration of the wheel, etc.
The three hydraulic modes of holding and depressurization are selected, and the selected predetermined ABS operation signal is output to the hydraulic unit 63. Hydraulic unit 63 has four wheels 33
The solenoid valve 66 is provided with a plurality of solenoid valves 66 for adjusting hydraulic pressure.
Control is performed so as to increase, hold, and reduce the brake pressure according to the S operation signal. The proportioning valve 64 is adapted to the left or right rear wheel 33 in accordance with the side of the left and right rear wheel 33 that is about to be locked.
At the same pressure. Here, the ABS operation signal A from the microcomputer 60
o is also configured to be output to the control unit 70 that performs electronic control of the continuously variable transmission 5. FIG. 3 shows an electronic control system of the proportional solenoids 51 and 56 in the hydraulic control system of the continuously variable transmission 5. This control system
As an input signal sensor of the control unit 70, a primary pulley rotation speed sensor 71, a secondary pulley rotation speed sensor 7
2, engine speed sensor 73, throttle opening sensor 74
And a pressure sensor 75 for detecting the secondary pressure Ps. Here, first, the control system of the proportional solenoid 51 for controlling the secondary pressure Ps will be described. The control unit 70 includes a throttle opening signal θ from the throttle opening sensor 74 and an engine speed signal Ne from the engine speed sensor 73.
Has an input engine torque calculation unit 76, and estimates the engine torque Te from the torque characteristic of θ-Ne. The engine 1 which is the input side of the torque converter 12
The rotation speed signal Ne and the rotation speed signal Np of the primary pulley 22, which is the output side, are input to the torque amplification ratio calculation unit 77, and the torque amplification ratio t according to the speed ratio n (Np / Ne) is determined. Further, the engine speed signal Ne and the primary pulley speed signal Np are input to a primary system inertia force calculation unit 78, and the inertia force gi is calculated from the mass and acceleration of the engine 1 and the primary pulley 22. And these engine torque Te, torque amplification rate t,
The signal of the inertia force gi is input to the input torque calculator 79, and the input torque Ti of the continuously variable transmission 5 is calculated as follows. Ti = Te · t-gi On the other hand, the actual speed ratio i (Np) is input by inputting the rotation speed signal Np of the primary pulley 22 and the rotation speed signal Ns of the secondary pulley 25.
/ Ns) for calculating the required secondary pressure Psu based on an input signal from the actual speed ratio calculating unit 85 for calculating the required secondary pressure Psu. Here, the secondary pressure Psu of the slip limit required for unit torque transmission is set for each actual speed ratio i as shown in FIG. 4 (a). From this map, the required secondary pressure Psu corresponding to the actual speed ratio i is determined. Psu is determined. Then, the input torque Ti, the signal of the required secondary pressure Psu, and the rotation speed signal Ns of the secondary pulley 25 are input to the target secondary pressure calculation unit 81, and the target secondary pressure Pss considering the centrifugal hydraulic pressure gs of the secondary cylinder 24 is taken into account. Is calculated as follows. Pss = Ti · Psu-gs + P M where P _M is the correction term expressed by P _M = f (i) as a function of the actual speed ratio i, and is called a margin. The target secondary pressure Pss is further adjusted by the solenoid current setting section 82.
To determine the solenoid current Is according to the target secondary pressure Pss. In this case, since the secondary control valve 50 has the characteristic of controlling the secondary pressure Ps in a proportional relation to the solenoid current Is as described above,
The solenoid current Is with respect to the target secondary pressure Pss is obtained in proportion to the map shown in FIG.
Then, this solenoid current Is is supplied to the proportional solenoid 51 of the secondary control valve 50 via the drive unit 83, and thus the secondary current Ps is directly controlled to follow the target secondary pressure Pss by the solenoid current Is. It has become. Subsequently, the proportional solenoid 56 for controlling the primary pressure Pp
Is described. First, as a basic concept of this control, since the actual speed ratio i in the steady state is determined by the hydraulic pressure ratio between the secondary pressure Ps and the primary pressure Pp, the hydraulic pressure ratio Kp (Pp / Ps)
Is expressed as a function of the actual transmission ratio i, and Kp = f (i). On the other hand, in the relationship between the primary pulley 22 and the driving pulley 26, when the input torque Ti increases, for example, the shift shifts in the downshift direction, and it is understood that the input torque Ti affects the actual speed ratio i. Therefore, this input torque
For the relationship between Ti and the actual transmission ratio i, the torque ratio K _T between the current maximum torque (Ps / Psu) that can be transmitted at the secondary pressure Ps and the input torque Ti of the current transmission torque is represented by K _T = Ti / ( Ps / Psu). Then, now the torque transmission state, i.e. Sadamari the actual gear ratio i in relation to the hydraulic ratio Kp, thereby hydraulic ratio Kp, the actual gear ratio i and the torque ratio K _T Kp as a function of the = f (i, K _T ) holds. In this way, the hydraulic ratio Kp is obtained from the actual speed ratio i and the torque ratio _KT with similar characteristics irrespective of the secondary pressure Ps, as shown in FIG. 4 (c). Primary pressure PPD required by secondary pressure Ps
Is calculated. As a result, the current input torque Ti
On the other hand, the primary pressure PPD required to maintain the current actual gear ratio i can be obtained for the secondary pressure Ps. Next, the shift control during the transition may be performed by controlling the flow rate according to a desired shift speed. Therefore, the pulley position change speed de / dt is calculated based on the shift speed or the pulley position based on the deviation between the target speed ratio is and the actual speed ratio i according to each driving and running condition. Where pulley position change speed d
Since e / dt is the volume change of the primary cylinder 21, that is, the flow rate, the opening area, that is, the valve displacement, is obtained using the equation of the valve flow rate, and the pulley position change speed is accordingly determined.
Convert to pressure Pp required to achieve de / dt. Then, the target primary pressure Pps is determined by adding or subtracting the pressure Pp to or from the required primary pressure PPD determined by the above-described hydraulic ratio control according to the upshift and the downshift. Therefore, based on the basic concept of the control, the control unit 70 has a hydraulic ratio control system and a flow control system. First, the hydraulic ratio control system will be described. The primary pulley rotation speed signal Np from the primary pulley rotation speed sensor 71 is described.
And a secondary pulley rotation speed signal Ns from the secondary pulley rotation speed sensor 72 to calculate an actual transmission ratio i (Np / Ns). On the other hand, it has a torque ratio calculating section 86 which receives the input torque Ti, the required secondary pressure Psu and the signal of the secondary pressure Ps of the pressure sensor 75 and calculates a torque ratio _KT.
The signals of K _T and the actual speed ratio i are inputted to the hydraulic ratio setting section 87, and the hydraulic ratio Kp is determined by the relationship between the torque ratio K _T and the actual speed ratio i according to the map shown in FIG. The signals of the hydraulic pressure ratio Kp and the secondary pressure Ps are input to the required primary pressure calculation unit 88, and further, taking into consideration the centrifugal hydraulic pressure gp of the primary cylinder 21 portion based on the primary pulley rotation speed Np, the required primary pressure PPD is calculated as follows. calculate. PPD = Kp.Ps-gp Next, the flow rate control system will be described. The target primary pulley rotation speed search unit 89 for inputting the signal of the actual gear ratio i and the throttle opening signal θ is provided. The pulley rotation speed NPD is determined. The target primary pulley rotation speed NPD and the secondary pulley rotation speed Ns
Is input to the target gear ratio calculator 90, and the target gear ratio is
Is calculated from is = NPD / Ns. Thus, the target speed ratio is determined according to each driving and running condition based on the speed change pattern. Here, the oil amount V of the primary cylinder 21 is proportional to the actual pulley position e, and the flow rate Q obtained by differentiating the oil amount V with time corresponds to the pulley position change speed de / dt on a one-to-one basis. Therefore, since the flow rate Q is preferably calculated as it is from the pulley position change speed de / dt, the actual speed ratio i and the target speed ratio is determined by the actual pulley position conversion unit 91 and the target pulley position conversion unit 92. Convert to target pulley position es. The actual pulley position e and the target pulley position es are input to the pulley position change speed calculation unit 93, and the pulley position change speed de / dt is calculated as
It is calculated from the deviation between the actual pulley position e and the target pulley position es as described below. de / dt = K1 · (es−e) · K2 · des / dt (K1, K2: constant, des / dt: phase advance element) The pulley position change speed de / dt is calculated by the shift pressure calculation unit 94.
To obtain the pressure ΔPp required for shifting based on the flow rate based on the pulley position change speed de / dt. Thus, the required primary pressure PPD of the hydraulic pressure ratio control system and the shift pressure ΔPp of the flow rate control system are equal to the target primary pressure calculation unit 95.
To the target primary pressure Pps, Pps = PPD + ΔPp at the time of upshift, and Pps = P at the time of downshift.
It is calculated by PD-ΔPp. Then, the calculated target primary pressure Pps is further input to a solenoid current setting unit 96,
A solenoid current Ip corresponding to the target primary pressure Pps is determined. In this case, as described above, the primary control valve 55 has a primary pressure proportional to the solenoid current Ip.
Since this is a characteristic for controlling Pp, the solenoid current Ip with respect to the target primary pressure Pps is obtained from the map shown in FIG. And this solenoid current Ip
Is supplied as a gear ratio control signal to the proportional solenoid 56 of the primary control valve 55 via the drive unit 97, so that the gear ratio is controlled by feedforward. Here, the control unit 70 is provided with an ABS operation detecting section 100, a control signal holding section 101, and an output switching section 102 in order to perform appropriate shift control corresponding to the ABS operation. The ABS operation detecting section 100 receives an ABS operation signal Ao from the ABS microcomputer 60 and detects when the ABS is operating. The control signal hold unit 101 receives the detection signal As from the ABS operation detection unit 100 and the signal of the solenoid current Ip as a gear ratio control signal, and outputs the signal level of the solenoid current Ip when the detection signal As is input. As a hold signal Iph, and this is output until the input of the detection signal As stops. Further, the output switching unit 102 receives the solenoid current Ip signal and the hold signal Iph held by the control signal holding unit 101 so as to input the solenoid current setting unit 9.
6 and the drive unit 97, and the solenoid current Ip
The hold signal Iph is output in preference to the signal of. Next, the operation of the shift control device for a continuously variable transmission having the above configuration will be described. First, the oil pump 34 is driven from the converter cover 11 of the torque converter device 3 via the rear drive shaft 35 by the operation of the engine 1, and the pump oil pressure is guided to the secondary control valve 50. Here, a description will be given of a normal traveling of a vehicle in which the ABS control is not performed. When the vehicle stops, the target speed ratio is and the actual speed ratio i of the primary control system are set as the maximum speed ratio on the mechanism of the continuously variable transmission 5, for example. Set to a value greater than 2.5. Therefore, the actual gear ratio i, the torque ratio K _T , the hydraulic ratio Kp, the secondary pressure
A target primary pressure Pps corresponding to Ps is calculated, and a solenoid current Ip corresponding to the target primary pressure Pps is supplied to the proportional solenoid 56 of the primary control valve 55 via the output switching unit 102 and the driving unit 56. By operating the primary cylinder 21 on the oil drain side in this way, the primary pressure Pp becomes the lowest level. Therefore, all of the secondary pressure Ps by the secondary control valve 50 is supplied only to the secondary cylinder 24, and the continuously variable transmission 5 is in the low speed stage with the maximum speed ratio at which the drive belt 26 is shifted to the secondary pulley 25 most. At this time, the lock-up clutch 15 is released by a hydraulic control system (not shown), and the torque converter 12 is supplied with oil. Therefore, for example, when shifting to the drive range, the forward clutch 17 of the forward / reverse switching device 4 is engaged by refueling to be in the forward position. For this reason, the power of the engine 1 is input to the primary shaft 20 of the continuously variable transmission 5 via the torque converter 12 and the forward / reverse switching device 4, and the primary pulley 22
Then, power of the maximum speed ratio is output to the secondary shaft 23 via the drive belt 26 and the secondary pulley 25, and this power is transmitted to the wheels 33 via the differential device 6 to be able to start. In the secondary pressure control system, the engine torque Te is always estimated, and the torque amplification factor t and the primary system inertia force gi are calculated. Therefore, when starting the accelerator step,
Input torque Ti according to engine torque Te and torque amplification factor t
And the required secondary pressure Psu also increases, so that the target secondary pressure Pss becomes a large value. And a low value solenoid current I according to the target secondary pressure Pss
By supplying s to the proportional solenoid 51 of the secondary control valve 50 via the drive unit 83, the secondary pressure Ps is controlled to be high by reducing the drain amount. After starting, the gearshift is controlled and the lock-up clutch is
15 is engaged, the torque amplification factor t becomes 1, the required secondary pressure Psu decreases in accordance with the actual gear ratio i, and when the engine torque Te is reduced with increasing vehicle speed, the target secondary pressure Psu is reduced.
Pss decreases rapidly. Therefore, the solenoid current Is
Increases rapidly, the set pressure of the secondary control valve 50 gradually decreases, and the secondary pressure Ps is controlled to decrease. Here, the characteristics of the secondary pressure Ps are summarized as shown in FIG. 5 (a), and the optimal control is performed so as to always secure the minimum pulley pressing force that does not cause belt slip with respect to the transmission torque. The secondary pressure Ps is guided to the primary control valve 55,
The primary pressure Pp is generated in the primary cylinder 21 by the pressure reducing action, and the speed is controlled by the primary pressure Pp.
This is described below. First, when the maximum speed ratio iL starts, the primary control valve 55 performs the maximum pressure reducing operation by the hydraulic ratio control system, and the primary pressure
Pp is kept at the lowest level. When the shift start condition of the target gear ratio is <2.5 is satisfied by the driving and running conditions, and the target gear ratio is set to be gradually smaller, the pulley position change speed de / dt is calculated by the flow control system. Accordingly, a shift pressure ΔPp is generated to increase the target primary pressure Pps. For this reason, the solenoid current Ip is gradually reduced, the set pressure of the primary control valve 55 is increased by the electromagnetic force of the proportional solenoid 56, and the primary pressure Pp is controlled to be sequentially increased. Then, the drive belt 26 moves to the primary pulley 22 and
Upshift to a higher gear with a smaller gear ratio. When the actual speed ratio i decreases due to the shift control, the hydraulic ratio Kp is increased by the hydraulic ratio setting unit 87 of the hydraulic ratio control system,
The ratio of the required primary pressure PPD to the secondary pressure Ps is increased. The target primary pressure Pps increases due to the increase in the required primary pressure PPD, and the level of the primary pressure Pp is maintained at an increased level. Thus, each time the actual gear ratio i decreases due to the upshift, the hydraulic gear ratio control system controls the actual gear ratio i. The primary pressure Pp is sequentially controlled to increase to a level that maintains i. Further, for example, when the input torque Ti increases, the torque ratio _KT becomes a large value in the torque ratio calculating section 86.
The value of Kp also increases. Therefore, the primary pressure Pp is corrected to increase, and is corrected so as to prevent the downshift tendency by increasing the input torque Ti. When the target speed ratio is reaches the minimum speed ratio iH (for example, 0.5) and the target primary pressure Pps is set to the highest level, the solenoid current Ip becomes the smallest and the set pressure of the primary control valve 55 becomes the maximum. As a result, the primary pressure Pp is controlled to the maximum. At this time, when the actual speed ratio i also reaches the minimum speed ratio iH following the target speed ratio is, thereafter, the target primary pressure Pps is set to the highest level by the hydraulic ratio Kp of the hydraulic ratio control system and the required primary pressure PPD. As a result, the primary pressure Pp is maintained at a high state to maintain the minimum speed ratio iH. On the other hand, when the value of the target speed ratio is increases due to depression of the accelerator, a decrease in the vehicle speed, or the like, the target primary pressure Pps becomes a low level due to the subtraction of the shift pressure ΔPp. For this reason,
On the contrary, the solenoid current Ip increases and the primary control valve 55
, The primary pressure Pp is controlled to a low level by the pressure reduction.
Shift to and downshift. Also in the case of this downshift, the hydraulic ratio control system controls the hydraulic ratio according to the increase of the actual gear ratio i.
Kp, target primary pressure Pps by required primary pressure PPD
Is decreased, and the primary pressure Pp is sequentially controlled to decrease to a level necessary to maintain the actual speed ratio i. In this way, the primary pressure Pp is made variable by the hydraulic ratio control system and the flow rate control system over the entire shift range of the maximum speed ratio iL and the minimum speed ratio iH as shown in FIG. The shift is controlled by shifting. Next, a description will be given of shift control in the case where ABS control is performed by a brake operation of the vehicle. The microcomputer 60 of the ABS control system calculates the speed, acceleration / deceleration, estimated vehicle speed, and the like of each wheel 33 based on the detection signal of each wheel speed sensor 65. Therefore, when the brake is suddenly applied, the wheels 33 are decelerated, so that the ABS control is started based on the judgment of the microcomputer 60. That is, the microcomputer 60 outputs an ABS operation signal to the hydraulic unit 63 so that the slip ratio of the wheel 33 falls within an appropriate range. And based on this ABS operation signal, each solenoid valve in the hydraulic unit 63
66 appropriately controls the brake pressure of each wheel 33 to three hydraulic modes of increasing, maintaining, and reducing the pressure, and thus the vehicle secures sufficient braking force and steering performance. Here, when the microcomputer 60 outputs the ABS operation signal Ao, the control unit performs electronic control of the continuously variable transmission 5.
In 70, the ABS operation detection unit 100 that has received the ABS operation signal Ao outputs the detection signal As. Therefore, the control signal hold unit 101
Holds the gear ratio control signal when the detection signal As is input, that is, the signal level of the solenoid current Ip, and this hold signal Iph is given priority over the signal of the solenoid current Ip by the output switching unit 102 to the drive unit 97. Is output to Therefore, when the ABS control is performed, the above-described normal speed ratio control is temporarily suspended, and the actual speed ratio i is maintained so as to follow the target speed ratio is immediately before the ABS operation. Therefore, unnecessary shifting operation is not performed, and the primary pressure Pp and the secondary pressure Ps of the hydraulic control system are maintained at the predetermined values, so that the slip of the drive belt 26 is prevented. When the output of the ABS operation signal from the microcomputer 60 stops due to the release of the brake operation, the ABS operation detection unit 10
0 stops the output of the detection signal As, and the control signal holding unit 101 stops the output of the hold signal Iph accordingly.
The output switching unit 102 outputs a signal of the solenoid current Ip as a speed ratio signal to the drive unit 97, and thus returns to the normal speed ratio control. Therefore, at the time of releasing the brake operation, it is possible to quickly perform the return control from the actual gear ratio i immediately before the ABS operation to the normal target gear ratio is. Although one embodiment of the present invention has been described above, the configuration of the present invention is not limited to this embodiment. For example,
The control unit 70 may be provided with a hold signal blocking unit that blocks the input of the hold signal Iph to the output switching unit 102 except when the throttle is fully closed based on the throttle opening signal θ of the throttle opening sensor 74. In this way, the normal speed change control can be quickly returned by the accelerator operation. Further, a rotation sensor for detecting the rotation speed of the secondary pulley 25 of the continuously variable transmission 5 is provided, and when the rotation speed of the secondary pulley 25 is equal to or less than a predetermined value based on a detection signal of the rotation sensor, the output switching unit 102 is The control unit 70 may be provided with a hold signal blocking unit for blocking the input of the hold signal Iph. In this case, when the rotation output of the secondary pulley 25 becomes equal to or less than the predetermined value, it is immediately determined that the ABS operation has been released, and the normal speed change control can be promptly returned. Further, in the case of a vehicle not equipped with ABS, a wheel speed sensor and a wheel deceleration detecting unit for detecting when the wheel speed is decelerated based on the detection signal are provided in the control unit 70, and the output of the wheel deceleration detecting unit is provided. By inputting a signal to the ABS operation detecting unit 100, the gear ratio may be maintained at the time immediately before the brake operation in the event of sudden braking.

【The invention's effect】

As described above, according to the present invention, during normal traveling of a vehicle in which ABS control is not performed, the continuously variable transmission is steplessly controlled to the optimum gear ratio in accordance with the gear ratio control signal output from the control unit. . Here, when the ABS control is performed by the brake operation of the vehicle, the ABS operation detecting unit outputs a detection signal, and the control signal holding unit holds the speed ratio control signal immediately before the ABS operation. The hold signal is output by the output switching section prior to the gear ratio control signal, so that the normal gear ratio control is temporarily suspended, and the gear ratio is held at the gear ratio immediately before the ABS operation. For this reason, unnecessary shift operations are eliminated, and the line pressure and the secondary pressure of the hydraulic control system are maintained at predetermined values, so that belt slippage can be prevented. Further, when the brake operation is released, it is possible to quickly return to the normal speed ratio from the speed ratio immediately before the ABS operation.

[Brief description of the drawings]

FIG. 1 is a schematic overall configuration diagram of a shift control device of a continuously variable transmission according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram of an ABS, and FIG. 3 is an electronic control in a shift control device of a continuously variable transmission. FIG. 4 (a) is a relationship map diagram of the actual speed ratio i and the secondary pressure Psu, and FIG. 4 (b) is a solenoid current Is and a target secondary pressure Ps.
FIG. 4 (c) is a relationship map between the torque ratio _KT and the hydraulic ratio Kp, FIG. 5 (a) is a characteristic diagram of the secondary pressure, and FIG. FIG. 5B is a diagram showing a shift pattern of the primary pressure. DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Crankshaft, 3 ... Torque converter device, 4 ... Forward / reverse switching device, 5 ... Continuously variable transmission, 6 ... Differential device, 20 ... Primary shaft, 21 ... Primary Cylinder, 22: Primary pulley, 23: Secondary shaft, 24: Secondary cylinder, 25: Secondary pulley, 26: Drive belt, 33: Wheel, 34: Oil pump, 50: Secondary control valve, 51: Proportional solenoid, 55: Primary control valve, 56: Proportional solenoid, 60: Microcomputer, 61: Master cylinder, 63: Hydraulic unit, 64: Proportioning valve, 65: Wheel speed Sensor, 66 Solenoid valve, 70 Control unit, 71 Primary pulley rotational speed sensor, 72 Secondary pulley rotational speed sensor, 7 3 ... Engine speed sensor 74 ... Throttle opening sensor 75 ... Pressure sensor 96 ... Solenoid current setting unit 97 ... Drive unit 100 ... ABS operation detection unit 101 ... Control signal hold , 102 Output switching unit.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60K 41/00-41/28 B60T 7/12-7/22 B60T 8/32-8/96 F16H 59 / 00-63/48 F16H 9/00

Claims (3)

(57) [Claims] 1. A continuously variable transmission that continuously controls a speed ratio of a continuously variable transmission mounted on a vehicle having an antilock brake system according to a speed ratio control signal output from a control unit. In the shift control device, the control unit of the shift control device includes an anti-lock brake system operation detecting unit that detects when the anti-lock brake system is operating, and an anti-lock brake system operation detecting unit. A control signal holding unit for holding the gear ratio control signal immediately before the operation of the antilock brake system when an operation signal is input from the control unit; and an output for receiving the gear ratio control signal and the hold signal from the control signal holding unit. And a switching unit, wherein the output switching unit is configured to operate the antilock brake system while the antilock brake system is operating. A transmission control device for a continuously variable transmission, wherein a transmission ratio control signal held by a control signal holding unit is continuously output with priority. 2. The control unit according to claim 1, further comprising a hold signal blocking section for blocking the input of a hold signal to said output switching section when the throttle is not fully closed based on a detection signal of a throttle opening sensor. The shift control device for a continuously variable transmission according to claim 1, wherein: 3. The continuously variable transmission is a belt-type continuously variable transmission that transmits power from a primary pulley to a secondary pulley, and includes a rotation sensor that detects a rotation speed of the secondary pulley. 2. The stepless control device according to claim 1, wherein a hold signal blocking unit for blocking the input of the hold signal to the output switching unit when the rotation speed of the secondary pulley is equal to or less than a predetermined value is provided in the control unit. Transmission control device for transmission.